FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Alton, GD Welton, RF Williams, C Cui, B Murray, SN AF Alton, GD Welton, RF Williams, C Cui, B Murray, SN TI Prototype negative-ion sources for radioactive ion-beam generation SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID FACILITY; HALOGENS AB Radioactive ion beams (RIBs) of F-17 and F-18 are of interest for investigation of astrophysical phenomena such as the ''hot'' CNO cycle and the rp stellar nuclear synthesis processes. In order to generate useful beam intensities of atomic F-, the species must be efficiently and expediently released from the target material, thermally dissociated from fluoride release products during transport to the ionization chamber of the ion source, and efficiently ionized in the source upon arrival. We have conceived and evaluated two prototype negative-ion sources for potential use for RIB generation: (1) a direct extraction source and (2) a kinetic-ejection source. Both sources utilize Cs vapor to enhance F- formation. The mechanical design features, operational parameters, ionization efficiencies for forming atomic F-, and delay times for transport of F and fluoride compounds for the respective sources are presented. The efficiency eta for formation and extraction of F- for the direct extraction negative-ion source is found to be eta similar to 1.0% while the characteristic delay time tau for transport of F and fluorides through the source is, typically, eta similar to 120 s; the analogous efficiencies and delay times for the kinetic ejection negative-ion source are,respectively: eta=similar to 3.2% and tau=similar to 70 s. (C) 1998 American Institute of Physics. [S0034-6748(98)05406-9]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Engn, Oak Ridge, TN 37831 USA. China Inst Atom Energy, Beijing, Peoples R China. RP Alton, GD (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 38 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2313 EP 2319 DI 10.1063/1.1148937 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100016 ER PT J AU Stenner, RD Merdink, JL Fisher, JW Bull, RJ AF Stenner, RD Merdink, JL Fisher, JW Bull, RJ TI Physiologically-based pharmacokinetic model for trichloroethylene considering enterohepatic recirculation of major metabolites SO RISK ANALYSIS LA English DT Article DE trichloroethylene; PBPK models; toxicokinetics; enterohepatic recirculation ID SPECIES-DIFFERENCES; TRICHLOROACETATE; DICHLOROACETATE; LIVER AB Trichloroacetic acid (TCA) is a major metabolite of trichloroethylene (TRI) thought to contribute to its hepatocarcinogenic effects in mice. Recent studies have shown that peak blood concentrations of TCA in rats do not occur until approximately 12 hours following an oral dose of TRI. However, blood concentrations of TRI reach a maximum within an hour and are nondetectable after 2 hours.((1)) The results of a study which examined the enterohepatic recirculation (EHC) of the principle TRI metabolites((2)), was used to develop a physiologically-based pharmacokinetic model for TRI, which includes enterohepatic recirculation of its metabolites. The model quantitatively predicts the uptake, distribution and elimination of TRI, trichloroethanol, trichloroethanol-glucuronide, and TCA and includes production of metabolites through the enterohepatic recirculation pathway. Physiologic parameters used in the model were obtained from the literature.((3, 4)) Parameters for TRI metabolism were taken from Fisher et al.((5)) Other kinetic parameters were found in the literature or estimated from experimental data.((2)) The model was calibrated to data from experiments of an earlier study where TRI was orally administered.((2)) Verification of the model was conducted using data on the enterohepatic recirculation of TCEOH and TCA,((2)) chloral hydrate data (infusion doses) from Merdink,((6)) and TRI data from Templin((1)) and Larson and Bull.((7)). C1 Pacific NW Lab, Richland, WA 99352 USA. Washington State Univ, Pharmacol Toxicol Program, Pullman, WA 99164 USA. Armstrong Lab, Wright Patterson AFB, OH 45433 USA. RP Stenner, RD (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 16 TC 12 Z9 12 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD JUN PY 1998 VL 18 IS 3 BP 261 EP 269 DI 10.1111/j.1539-6924.1998.tb01293.x PG 9 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA ZZ433 UT WOS:000074728900007 PM 9664722 ER PT J AU Hyman, JM Li, J AF Hyman, JM Li, J TI Modeling the effectiveness of isolation strategies in preventing STD epidemics SO SIAM JOURNAL ON APPLIED MATHEMATICS LA English DT Article DE sexually transmitted disease models; selective mixing; partner formations; behavior changes; reproductive numbers; endemic equilibrium; local stability; global stability ID SEXUAL-BEHAVIOR; SAN-FRANCISCO; HOMOSEXUAL MEN; RISK BEHAVIOR; AIDS; HIV; POPULATION; VACCINES; SPREAD AB We formulate and analyze a two-group, selective-mixing, susceptible-infective-susceptible (SIS), sexually transmitted disease (STD) model where the infection-dependent desirability and acceptability in partnership formations are zero at high infection levels. We analyze two strategies to limit the spread of the epidemic by avoiding forming partnerships with people in a highly infected group. In one approach, the people in the highly infected group protect themselves by forming partnerships with only people outside their own group. We show that the transmission dynamics for this approach are similar to the situation where people continue to have both intragroup and intergroup partnerships. In the second approach, when one group becomes highly infected, the people in the other group adopt an isolation strategy and stop forming any partnerships with people in this highly infected group. We show that the second approach can limit the epidemic to the highly infected group. The other group will be infection-free, but as long as the epidemic in the total population exceeds the epidemic threshold, the epidemic will continue to persist. If the group reproductive number of the infection-free group is greater than one, and the infection should ever invade the infection-free group, then it will lead to an epidemic similar to the one that would have occurred if they had not isolated themselves from the other group. In this simple two-group model, although these isolation strategies may reduce the extent of an STD epidemic, they are ineffective in preventing an epidemic. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, Los Alamos, NM 87545 USA. Univ Alabama, Dept Math Sci, Huntsville, AL 35899 USA. RP Hyman, JM (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, MS-B284, Los Alamos, NM 87545 USA. NR 25 TC 20 Z9 23 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1399 J9 SIAM J APPL MATH JI SIAM J. Appl. Math. PD JUN PY 1998 VL 58 IS 3 BP 912 EP 925 DI 10.1137/S003613999630561X PG 14 WC Mathematics, Applied SC Mathematics GA ZF956 UT WOS:000072950100003 ER PT J AU Barenblatt, GI Chorin, AJ AF Barenblatt, GI Chorin, AJ TI New perspectives in turbulence: Scaling laws, asymptotics, and intermittency SO SIAM REVIEW LA English DT Article DE turbulence; intermittency; scaling; wall-bounded turbulence; local structure; statistical theory ID VORTEX FILAMENT; SHEAR FLOWS; STATISTICS AB Intermittency, a basic property of fully developed turbulent ow, decreases with growing viscosity; therefore classical relationships obtained in the limit of vanishing viscosity must be corrected when the Reynolds number is finite but large. These corrections are the main subject of the present paper. They lead to a new scaling law for wall-bounded turbulence, which is of key importance in engineering, and to a reinterpretation of the Kolmogorov-Obukhov scaling for the local structure of turbulence, which has been of paramount interest in both theory and applications. The background of these results is reviewed, in similarity methods, in the statistical theory of vortex motion, and in intermediate asymptotics, and relevant experimental data are summarized. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Barenblatt, GI (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. EM chorin@math.berkeley.edu NR 53 TC 36 Z9 37 U1 0 U2 4 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD JUN PY 1998 VL 40 IS 2 BP 265 EP 291 DI 10.1137/S0036144597320047 PG 27 WC Mathematics, Applied SC Mathematics GA ZN816 UT WOS:000073685500004 ER PT J AU Ahuja, R Auluck, S Eriksson, O Wills, JM Johansson, B AF Ahuja, R Auluck, S Eriksson, O Wills, JM Johansson, B TI Calculated optical properties of a solar energy material: CuGaS2 SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article DE electronic structure; optical properties; chalcopyrite structure ID CHALCOPYRITE SEMICONDUCTORS; BRILLOUIN-ZONE; SPECIAL POINTS; HIGH-PRESSURE; SPECTRA; DENSITY; SYSTEMS; ZNGEP2; BAND; ABSORPTION AB The full-potential linear muffin-tin orbital method is used to study the electronic structure of the solar energy material CuGaS2. From this the optical reflectivity is calculated and compared with experiment, both for the case when the polarization vector of the light, E is parallel to the c-axis and when E is perpendicular to the c -axis. An encouraging agreement with experiment is obtained. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Uppsala Univ, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. Univ Roorkee, Dept Phys, Roorkee 247667, Uttar Pradesh, India. RP Ahuja, R (reprint author), Uppsala Univ, Dept Phys, Condensed Matter Theory Grp, Box 530, S-75121 Uppsala, Sweden. EM rajeev.ahuja@fysik.uu.se RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 51 TC 14 Z9 14 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 EI 1879-3398 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD JUN PY 1998 VL 53 IS 3-4 BP 357 EP 366 DI 10.1016/S0927-0248(98)00034-8 PG 10 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA ZY467 UT WOS:000074624200016 ER PT J AU McCluskey, MD Haller, EE Walukiewicz, W Becla, P AF McCluskey, MD Haller, EE Walukiewicz, W Becla, P TI Anti-crossing behavior of local vibrational modes in AlSb SO SOLID STATE COMMUNICATIONS LA English DT Article DE semiconductors; impurities in semiconductors; phonons ID HYDROGEN COMPLEXES; CELL AB Using infrared spectroscopy we have observed a resonant interaction between local vibrational modes (LVM's) and unidentified modes in AlSb. This interaction leads to a splitting of the Se-H stretch mode into three peaks at 1606.3, 1608.6 and 1615.7 cm(-1) at liquid-helium temperatures. As the temperature or pressure is increased, the peaks show anti-crossing behavior. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP McCluskey, MD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 11 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD JUN PY 1998 VL 106 IS 9 BP 587 EP 590 DI 10.1016/S0038-1098(98)00095-7 PG 4 WC Physics, Condensed Matter SC Physics GA ZL935 UT WOS:000073488300007 ER PT J AU Lee, JW MacKenzie, KD Johnson, D Shul, RJ Pearton, SJ Abernathy, CR Ren, F AF Lee, JW MacKenzie, KD Johnson, D Shul, RJ Pearton, SJ Abernathy, CR Ren, F TI Device degradation during low temperature ECR-CVD. Part I: GaAs MESFET's SO SOLID-STATE ELECTRONICS LA English DT Article ID PLASMA-INDUCED DAMAGE; SEMICONDUCTORS; PASSIVATION; FABRICATION; ALGAAS; HEMTS; GATE AB The effects of plasma chemistry (SiH4/NH3, SiH4/N-2 Or SiH4/N2O) and deposition conditions (temperature, source power, pressure, SiH4 percentage and additional Ar flow) during electron cyclotron resonance chemical vapor deposition of SiNx or SiO2 onto GaAs MESFETs are reported. Device degradation, as measured by the effect on transconductance, threshold voltage, breakdown voltage and gate ideality factor, is due to two mechanisms-passivation of Si dopants in the channel by atomic hydrogen, and near-surface doping or stoichiometry changes induced by ion bombardment or preferential loss of As. Conditions which minimize hydrogen ion and neutral densities produce the least degradation in MESFET performance. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Plasma Therm Inc, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Lee, JW (reprint author), Plasma Therm Inc, St Petersburg, FL 33716 USA. RI Schaff, William/B-5839-2009 NR 31 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUN PY 1998 VL 42 IS 6 BP 1015 EP 1020 DI 10.1016/S0038-1101(98)00116-6 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZX673 UT WOS:000074542500021 ER PT J AU Lee, JW MacKenzie, KD Johnson, D Shul, RJ Pearton, SJ Abernathy, CR Ren, F AF Lee, JW MacKenzie, KD Johnson, D Shul, RJ Pearton, SJ Abernathy, CR Ren, F TI Device degradation during low temperature ECR-CVD. Part II: GaAs/AlGaAs HBTs SO SOLID-STATE ELECTRONICS LA English DT Article ID HETEROJUNCTION BIPOLAR-TRANSISTORS; MOLECULAR-BEAM EPITAXY; DAMAGE INTRODUCTION; MOMBE; GROWTH; CARBON; GAAS; HYDROGEN AB GaAs/AlGaAs heterojunction bipolar transistors were coated with thin (< 200 Angstrom) SiNx or SiO2 layers using electron cyclotron resonance chemical vapor deposition.The process variables were deposition temperature (25-120 degrees C), source power (150-700 W), SiH4 percentage (20-50%), process pressure (15-40 mTorr) and additional Ar flow rate (0-20 sccm). HBT de parameters were least degraded at high SiH4 percentages in all the plasma chemistries investigated (SiH4/NH3, SiH4/N-2, SiH4/N2O), at moderate source powers (200-500 W), at pressures around 15 mTorr, and at zero Ar flow rates. Deposition temperature had a significant effect only for the SiH4/NH3 chemistry, where hydrogen passivation was more efficient at temperatures above 100 degrees C. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Plasma Therm Inc, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Lee, JW (reprint author), Plasma Therm Inc, St Petersburg, FL 33716 USA. RI Schaff, William/B-5839-2009 NR 34 TC 11 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUN PY 1998 VL 42 IS 6 BP 1021 EP 1025 DI 10.1016/S0038-1101(98)00117-8 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZX673 UT WOS:000074542500022 ER PT J AU Lee, JW MacKenzie, K Johnson, D Shul, RJ Pearton, SJ Ren, F AF Lee, JW MacKenzie, K Johnson, D Shul, RJ Pearton, SJ Ren, F TI Low temperature ECR-CVD of SiNx for III-V device passivation SO SOLID-STATE ELECTRONICS LA English DT Article ID GAAS/ALGAAS MICRODISK LASERS; FIELD-EFFECT TRANSISTORS; Y-GATE; POWER; FABRICATION; EFFICIENCY; PLASMA; INGAAS AB Electron Cyclotron Resonance SiH4/N-2 and SiH4/NH3 discharges have been employed for deposition of SiNx over a range of temperatures (25-120 degrees C), source powers (200-700 W), pressures (15-40 mTorr), SiH4 percentages (20-50%) and additional Ar flow rates (0-30 seem). Deposition rates were in the range 100-700 Angstrom min(-1), with refractive indices df 1.7-2.3. The SiH4/N-2 chemistry allowed a wider process window for tailoring the stress in the SiNx films, with chuck temperature, ECR source power, chamber pressure, SiH4 composition and Ar addition all producing a transition from compressive to tensile stress, or vice-versa. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Plasma Therm Inc, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Lee, JW (reprint author), Plasma Therm Inc, St Petersburg, FL 33716 USA. NR 22 TC 9 Z9 12 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUN PY 1998 VL 42 IS 6 BP 1031 EP 1034 DI 10.1016/S0038-1101(98)00118-X PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZX673 UT WOS:000074542500024 ER PT J AU Oikawa, K Kamiyama, T Izumi, F Chakoumakos, BC Ikuta, H Wakihara, M Li, JQ Matsui, Y AF Oikawa, K Kamiyama, T Izumi, F Chakoumakos, BC Ikuta, H Wakihara, M Li, JQ Matsui, Y TI Structural phase transition of the spinel-type oxide LiMn2O4 SO SOLID STATE IONICS LA English DT Article DE lithium manganese oxide; structural phase transition; neutron powder diffraction ID BATTERIES; MAGNETITE; CATHODE; FE3O4 AB The crystal structure of the low-temperature (LT) form of spinel-type LiMn2O4, has been studied by neutron and X-ray powder diffraction as well as electron diffraction. Reflections of the LT phase in its neutron and X-ray diffraction patterns were indexed on the basis of not a tetragonal unit cell but roughly an orthorhombic one (space group Fddd) with lattice parameters a = 8.2797(2), b = 8.2444(3) and c = 8.1981(2) Angstrom. However, the presence of extra reflections which cannot be indexed with this unit cell shows that the actual lattice parameters ale different from the above ones. Superlattice reflections, which were missing in powder diffraction patterns, with tripled periodicity were observed in election diffraction patterns of the LT phase. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan. Univ Tsukuba, Natl Inst Res Inorgan Mat, Tsukuba, Ibaraki 305, Japan. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Tokyo Inst Technol, Dept Chem Engn, Meguro Ku, Tokyo 152, Japan. RP Oikawa, K (reprint author), Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan. EM oikawa@mat.ims.tsukuba.ac.jp RI Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 17 TC 79 Z9 79 U1 2 U2 42 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD JUN PY 1998 VL 109 IS 1-2 BP 35 EP 41 DI 10.1016/S0167-2738(98)00073-3 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZQ962 UT WOS:000073920800004 ER PT J AU Brosha, EL Chung, BW Brown, DR Raistrick, ID Garzon, FH AF Brosha, EL Chung, BW Brown, DR Raistrick, ID Garzon, FH TI Amperometric oxygen sensors based on dense Tb-Y-Zr-O electrodes SO SOLID STATE IONICS LA English DT Article DE oxygen sensors; diffusion barriers; limiting current sensors ID TETRAGONAL ZIRCONIA POLYCRYSTALS; SOLID ELECTROLYTES; CONDUCTIVITY; ION AB The fabrication and operation of a new type of amperometric linear response oxygen sensor is demonstrated that utilizes a 16 mu m thick, dense Tb-YSZ film of composition Y0.2Tb0.24Zr0.56O2-y as a solid state chemical oxygen diffusion barrier. The device exhibits a near linear response between 750 and 850 degrees C between 0.2 and 4.5% O-2 in nitrogen. The effective linear range of operation at 800 degrees C is extended to above 8.0% O-2 With the application of albite (Na-Al-Si-O) glass to limit leakage at the edges (gas-substrate-diffusion barrier interface) of the device. Thin film high temperature cyclic voltammetry performed on Tb-YSZ films of similar stoichiometry indicate thermodynamic stability to below 10(-30) atm pO(2) at 750 degrees C. The initial performance of this device taken together with the inherent chemical stability of the diffusion barrier-suggests that devices of this type may be suitable for use as control sensors for lean-burn internal combustion engines. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Electr & Electrochem Mat & Devices Grp, Los Alamos, NM 87545 USA. RP Brosha, EL (reprint author), Univ Calif Los Alamos Natl Lab, Electr & Electrochem Mat & Devices Grp, Los Alamos, NM 87545 USA. EM brosha@lanl.gov RI Chung, Brandon/G-2929-2012 NR 17 TC 5 Z9 5 U1 3 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD JUN PY 1998 VL 109 IS 1-2 BP 73 EP 80 DI 10.1016/S0167-2738(98)00102-7 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZQ962 UT WOS:000073920800008 ER PT J AU Lee, SH Park, YS Joo, SK AF Lee, SH Park, YS Joo, SK TI Characterization of Ni-W oxide thin film electrodes SO SOLID STATE IONICS LA English DT Article DE anodic coloration; charge transfer density; co-sputtering; lithium intercalation; optical response; thin film ID NICKEL-OXIDE; LITHIUM AB Ni-W oxide thin films were fabricated by cc-sputtering of nickel and tungsten in oxygen ambient. It has been found that the tungsten amount is very closely related to the lithium intercalation kinetics. This new material has been found to show anodic coloration with lithium ions. Compared with NiOx, thin films, Ni-W oxide thin films showed considerable improvements in charge transfer density and optical response. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Seoul Natl Univ, Dept Mat Sci & Engn, Kwanak Ku, Seoul 151742, South Korea. RP Lee, SH (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Lee, Sehee/A-5989-2011 NR 10 TC 17 Z9 17 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD JUN PY 1998 VL 109 IS 3-4 BP 303 EP 310 DI 10.1016/S0167-2738(98)00093-9 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZT752 UT WOS:000074121600015 ER PT J AU Navratil, JD AF Navratil, JD TI The challenges of inorganic chemistry in the 21st century SO SOUTH AFRICAN JOURNAL OF CHEMISTRY-SUID-AFRIKAANSE TYDSKRIF VIR CHEMIE LA English DT Editorial Material AB The problems being addressed by inorganic chemistry in the 1990s will continue to be challenges well into the 21st century. For example, coordination chemistry will continue to provide compounds with unusual properties and uses, and will become an increasingly important component in bioinorganic chemistry. Nuclear technology will continue to challenge the inorganic chemist in issues related to the treatment of nuclear wastes and the cleanup of environmental contamination. Organometallic chemistry will continue as one of the most active areas of catalysis research, especially in the chemical, energy, pharmaceuticals and pollution control industries. Solid-state chemistry will advance with the growing requirements for better batteries, electronic components, photovoltaic devices, etc., and the synthetic procedures being conducted at high pressures and temperatures will assist the needs of geochemists. Synthetic inorganic chemistry will tend to be more directed to meeting specific goals, such as new compounds as reagents in organic synthesis, compounds with superconducting properties and inorganic polymers with unusual mechanical and thermal properties. New methods to meet the needs of the production of inorganic chemicals will involve environmental friendly synthesis. Thus inorganic chemistry will continue in importance to meet the needs for chemical, energy and materials production. C1 Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. RP Navratil, JD (reprint author), Idaho Natl Engn Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU BUREAU SCIENTIFIC PUBL PI PRETORIA PA P O BOX 2600, PRETORIA 0001, SOUTH AFRICA SN 0379-4350 J9 S AFR J CHEM-S-AFR T JI South Afr. J. Chem.-Suid-Afr. Tydskr. Chem. PD JUN PY 1998 VL 51 IS 2 BP 64 EP 65 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 111FH UT WOS:000075426300001 ER PT J AU Faulques, E Perry, DL Lott, S Zubkowski, JD Valente, EJ AF Faulques, E Perry, DL Lott, S Zubkowski, JD Valente, EJ TI Study of coordination and ligand structure in cobalt-EDTA complexes with vibrational microspectroscopy SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE cobalt; ethylenediaminetetraacetic acid; EDTA; micro-infrared spectroscopy; micro-Raman spectroscopy ID SELECTIVE COMPLEXOMETRIC DETERMINATION; REAGENT; CO AB Micro-Raman scattering experiments and micro-infrared absorption studies have been conducted on the cobalt-EDTA complexes [Co(H2O)H(2)EDTA]. 2H(2)O (I) and [Co(H2O)(6)](2+)[Co(H2O) HEDTA](2)(2-). 2H(2)O (II) (where HEDTA is the mono-protonated EDTA(4-) ligand anion, or HEDTA(3-), and EDTAH(2) is the di-protonated anion, or H(2)EDTA(2-), of the neutrally charged parent EDTA acid) that previously have been documented with respect to their structural chemistry. The two complexes have been found to exhibit vibrational spectra that allow one to differentiate them from one another. The vibrational data for the two compounds are discussed in relation to their structures, particularly with respect to subtle bonding differences of both the EDTA ligands and the coordinated and un-coordinated water molecules. Several vibrational assignments are proposed for both the EDTA and water molecules in the complexes for the variably protonated EDTA molecule. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Nantes, Inst Mat Nantes, Lab Phys Cristalline, CNRS,Unite Mixte Rech 110, F-44322 Nantes 03, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Jackson State Univ, Dept Chem, Jackson, MS 39217 USA. Mississippi Coll, Dept Chem, Clinton, MS 39058 USA. RP Faulques, E (reprint author), Univ Nantes, Inst Mat Nantes, Lab Phys Cristalline, CNRS,Unite Mixte Rech 110, BP 32229, F-44322 Nantes 03, France. NR 16 TC 14 Z9 14 U1 1 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD JUN PY 1998 VL 54 IS 6 BP 869 EP 878 DI 10.1016/S1386-1425(98)00012-2 PG 10 WC Spectroscopy SC Spectroscopy GA ZT747 UT WOS:000074121100009 ER PT J AU Vasanthamohan, N Singh, JP Lubke, KA AF Vasanthamohan, N Singh, JP Lubke, KA TI Strain tolerance of Ag-sheathed BSCCO (2223) superconductors with various geometrical configurations SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID CRITICAL-CURRENT DENSITY; TAPES; BI2SR2CACU2OX; DEFORMATION AB Strain tolerance (retained critical current as a function of applied strain) of Ag-sheathed monofilament and wire-in-tube (WIT) Bi-1.8 Pb0.4Sr2Ca2Cu3Ox tapes sintered for various time periods was evaluated. Strain tolerance of the WIT tapes sintered for 100 h was significantly lower than that of the monofilament tapes. This is attributed to a sharp increase in volume fraction of the superconducting core in WIT tapes (compared with that in monofilament tapes) subjected to a strain value greater than the fracture strain of BSCCO (approximate to 0.2%). This limitation was overcome by fabricating tube-within-tube tapes containing an additional BSCCO layer that runs along the neutral plane. Strain tolerance of these was superior to those of both the monofilament and the WIT configurations. This improvement is related to crack pinning effects induced by the inner Ag tube and by increased volume fraction of undamaged superconducting core. Experimental evidence indicates that the effective strain experienced by the current-carrying regions of the cross-section will determine the strain tolerance of the tape. At strains below 1% where there is a significant decrease in the volume fraction of superconducting core within subcritical strain, only a relatively low decrease in critical current density was observed, indicating possible current shunting in all of the tape configurations investigated. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Vasanthamohan, N (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD JUN PY 1998 VL 11 IS 6 BP 584 EP 589 DI 10.1088/0953-2048/11/6/007 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA ZU422 UT WOS:000074195500007 ER PT J AU Roos, KR Tringides, MC AF Roos, KR Tringides, MC TI Prefactor and step edge barrier determination for interlayer diffusion in homoepitaxial systems: Ag/Ag(111) SO SURFACE REVIEW AND LETTERS LA English DT Article ID BY-LAYER GROWTH; AG(111); AG; DIFFRACTION AB Interlayer diffusion is controlled by the probability that an atom will hop from a higher to a lower level. This probability depends on the additional step edge barrier Delta E-s which an atom experiences at a step because of the lower coordination as it moves over the;barrier, and possibly on the different prefactors v(s), v(t) for an atom at the step versus one at a terrace position. It is important to develop experimental methods that separate out the two contributions. We have reanalyzed the STM-based method,(1) which measures the fraction of islands with second layer occupation at different deposition temperatures, to show how the two contributions can be identified. In addition, we have developed a diffraction-based method that measures the step density of nucleated islands as they compete for atom capture with the steps at the perimeter of the terraces. RHEED experiments on Ag/Ag(lll) result in Delta E-s = 0.15 +/- 0.03 eV and v(s)/v(t) = 2.3 x 10(2+/-0.2), in good agreement with the results, Delta E-s = 0.13 +/- 0.03 eV and v(s)/v(t) = 10(3+/-0.3), deduced from the data of Ref. 1. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Bradley Univ, Dept Phys, Peoria, IL 61625 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Tringides, MC (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 13 TC 12 Z9 12 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD JUN-AUG PY 1998 VL 5 IS 3-4 BP 833 EP 840 DI 10.1142/S0218625X98001201 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 112HT UT WOS:000075488600020 ER PT J AU Maksym, PA Korte, U McCoy, JM Gotsis, HJ AF Maksym, PA Korte, U McCoy, JM Gotsis, HJ TI Calculation of RHEED intensities for imperfect surfaces SO SURFACE REVIEW AND LETTERS LA English DT Review ID ENERGY ELECTRON-DIFFRACTION; STEP-DENSITY; MICROSCOPY; TRANSITION; GROWTH AB RHEED calculation techniques for imperfect surfaces are reviewed and some applications of the calculational methods are described. Systems of interest typically consist of a perfectly ordered substrate which is periodic in three dimensions together with a surface which has imperfections in the form of disorder or steps. Calculational techniques for this type of system include: supercell methods in which the disorder is modeled by considering a large periodic system; perturbation theory in the distorted wave Born approximation where the scattering by the imperfections is taken to be a perturbation but the scattering by the periodic part of the system is treated exactly; the multislice method as used in transmission electron diffraction theory; and a promising new approach based on Green's functions. The validity of perturbation theory is investigated in detail and it is shown to give good agreement with supercell calculations in the case where the potential of the imperfections is weak or where their correlation length is small. This makes perturbation theory very suitable for treating disordered over, layers, but stepped surfaces with a large correlation length require the other methods. These methods are more expensive computationally and some possible ways of reducing the CPU time are considered. Finally, illustrative results are presented to show how the various calculational techniques can be applied to real systems. Particular cases include RHEED intensity oscillations and reflection electron microscope images. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Univ Osnabruck, Fachbereich Phys, D-49069 Osnabruck, Germany. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland. RP Maksym, PA (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. NR 24 TC 4 Z9 4 U1 2 U2 5 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD JUN-AUG PY 1998 VL 5 IS 3-4 BP 873 EP 880 DI 10.1142/S0218625X98001249 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 112HT UT WOS:000075488600024 ER PT J AU Stauber, AJ Bull, RJ Thrall, BD AF Stauber, AJ Bull, RJ Thrall, BD TI Dichloroacetate and trichloroacetate promote clonal expansion of anchorage-independent hepatocytes in vivo and in vitro SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article DE dichloroacetate (DCA); trichloroacetate (TCA); anchorage-independence; c-Jun; c-Fos; hepatocarcinogenesis; tumor promoter ID MALE B6C3F1 MOUSE; PRENEOPLASTIC FOCI; RAT HEPATOCYTES; RISK ASSESSMENT; STRAND BREAKS; LIVER INVIVO; ACID; INDUCTION; MICE; DNA AB Dichloroacetate (DCA) and trichloroacetate (TCA) are hepatocarcinogenic by-products of water chlorination and metabolites of several industrial solvents. To determine whether DCA and TCA promote the clonal expansion of anchorage-independent liver cells in vitro, a modification of the soft agar assay (over agar assay) was utilized to quantitate growth and analyze phenotype of anchorage-independent hepatocellular colonies. Hepatocytes from naive male B6C3F1 mice were isolated and cultured with 0-2.0 mM DCA or TCA over agar for 10 days, at which time colonies of eight cells or more were scored. Both DCA and TCA promoted the formation of anchorage-independent colonies in a dose-dependent manner. Immunocytochemical analysis using a c-Jun antibody demonstrated that colonies promoted by DCA were primarily c-Jun(+), whereas TCA-promoted colonies were primarily c-Jun(-). This corresponds to the differences in c-Jun immunoreactivity reported in tumors induced by DCA and TCA, Neither DCA nor TCA induced c-Jun expression in hepatocyte monolayers, indicating that these haloacetates selectively affect subpopulations of anchorage-independent hepatocytes. The latency of colony formation was decreased by the concentration of DCA, although the same number of colonies appeared after 25 days in culture at all DCA concentrations used. The plating density of hepatocytes also affected colony formation. At lower cell densities, promotion of colony formation by DCA was significantly reduced. Pretreatment of male B6C3F1 mice with 0.5 g/liter DCA in drinking water resulted in a fourfold increase in in vitro colony formation above hepatocytes isolated from naive mice, suggesting that DCA is promoting the clonal expansion of anchorage-independent hepatocytes in vivo. Results from this study indicate that DCA and TCA promote the survival and growth of initiated cells, Furthermore, results from over agar assays reflect observations made in vivo, indicating this assay provides a valid means to investigate the mechanism by which chemicals promote clonal expansion of initiated hepatocytes, (C) 1998 Academic Press. C1 Pacific NW Lab, Mol Biosci Dept, Richland, WA 99352 USA. Washington State Univ, Pharmacol Toxicol Grad Program, Pullman, WA 99164 USA. RP Stauber, AJ (reprint author), Pacific NW Lab, Mol Biosci Dept, MS-IN,P7-56,POB 999, Richland, WA 99352 USA. NR 39 TC 15 Z9 17 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD JUN PY 1998 VL 150 IS 2 BP 287 EP 294 DI 10.1006/taap.1998.8417 PG 8 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA ZY315 UT WOS:000074607800008 PM 9653059 ER PT J AU Hearst, JE Kauffman, L McClain, WM AF Hearst, JE Kauffman, L McClain, WM TI A simple mechanism for the avoidance of entanglement during chromosome replication SO TRENDS IN GENETICS LA English DT Article ID POLYMERASE-III HOLOENZYME; DNA-REPLICATION; TOPOISOMERASE; CLAMP AB The interphase nucleus of the human eukaryotic cell, before DNA replication, contains 46 linear DNA molecules, each of the order of centimeters in length, in spherical nucleus with a diameter of 3-10 mu m. Hour noes the cell avoid topological entanglements between the 92 linear DNA molecules following replication? A model of chromosome replication is introduced, based on the assumption of the existence of a Physical linkage between diverging growing forks during eukaryotic chromosome replication, This basic model is shown to be sufficient for the avoidance of DNA duplex entanglements during DNA replication. The model also suggests structural characteristics of chromosomes Rt various points in the cell cycle and provides a possible partial mechanism for chromosome condensation at the end of replication. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Struct Biol, Berkeley, CA 94720 USA. Univ Illinois, Dept Math, Chicago, IL 60680 USA. Wayne State Univ, Dept Chem, Detroit, MI 48202 USA. RP Hearst, JE (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM jehearst@lbl.gov; kauffman@uic.edu; wmm@chem.wayne.edu FU NIGMS NIH HHS [R01 GM 41911]; PHS HHS [A122636] NR 17 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0168-9525 J9 TRENDS GENET JI Trends Genet. PD JUN PY 1998 VL 14 IS 6 BP 244 EP 247 DI 10.1016/S0168-9525(98)01481-4 PG 4 WC Genetics & Heredity SC Genetics & Heredity GA ZT577 UT WOS:000074101800008 PM 9635408 ER PT J AU Larson, DJ Miller, MK Ulfig, RM Matyi, RJ Camus, PP Kelly, TF AF Larson, DJ Miller, MK Ulfig, RM Matyi, RJ Camus, PP Kelly, TF TI Field ion specimen preparation from near-surface regions SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT 44th International Field Emission Symposium CY JUL 07-11, 1997 CL NATL RES INST MET, TSUKUBA, JAPAN HO NATL RES INST MET DE atom probe field ion microscopy; specimen preparation; ion sputtering ID SCANNING ATOM-PROBE AB The feasibility of fabricating field ion specimens from planar surfaces by the technique of ion beam mask etching has been demonstrated. The production of an electric field at the tip apex sufficient to produce field evaporation has been accomplished by a combination of the minimization of the surface area, the increase in the tip height above the planar surface, and the minimization of the tip radius and shank angle. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Microscopy & Microanal Grp, Oak Ridge, TN 37831 USA. Univ Wisconsin, Dept Mat Sci & Engn, Madison, WI 53706 USA. Univ Wisconsin, Ctr Appl Superconduct, Madison, WI 53706 USA. RP Larson, DJ (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, Microscopy & Microanal Grp, POB 2008, Oak Ridge, TN 37831 USA. NR 17 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JUN PY 1998 VL 73 IS 1-4 BP 273 EP 278 DI 10.1016/S0304-3991(97)00167-8 PG 6 WC Microscopy SC Microscopy GA ZU834 UT WOS:000074240300041 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI Resonant tunneling in high-T-c superconductors SO USPEKHI FIZICHESKIKH NAUK LA Russian DT Review ID HIGH-TEMPERATURE SUPERCONDUCTORS; DIMENSIONAL COULOMB GAS; VALENCE-BOND STATE; OPTICAL CONDUCTIVITY; AXIS CONDUCTIVITY; SINGLE-CRYSTALS; PSEUDOGAP; TRANSPORT; BI2SR2CACU2O8; YBA2CU3OX AB A review is presented of the author's work on resonance tunneling as an electron transport mechanism along the c-axis in high-temperature layered cuprates. Problem formulation is given, qualitative aspects of the mechanism are described, and physical properties calculated. Comparisons are made with experimental data for the temperature dependence of normal conductivity, the frequency dependence of optical conductivity, and stationary supercurrent along the c-axis. For the latter property, resonance tunneling coherence of different centres is shown to be of crucial importance. Weakened interplane coupling and vortex fluctuations are invoked to explain the sharp drop in T-c and the rise in the 2 Delta(0)/T-c ratio with decreasing oxygen content. Simple example models are given to demonstrate major aspects of resonance tunneling. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Abrikosov, AA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 46 TC 16 Z9 16 U1 1 U2 2 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0042-1294 J9 USP FIZ NAUK+ JI Uspekhi Fiz. Nauk PD JUN PY 1998 VL 168 IS 6 BP 683 EP 695 PG 13 WC Physics, Multidisciplinary SC Physics GA 109WH UT WOS:000075347000009 ER PT J AU Zimmerman, DA de Marsily, G Gotway, CA Marietta, MG Axness, CL Beauheim, RL Bras, RL Carrera, J Dagan, G Davies, PB Gallegos, DP Galli, A Gomez-Hernandez, J Grindrod, P Gutjahr, AL Kitanidis, PK Lavenue, AM McLaughlin, D Neuman, SP RamaRao, BS Ravenne, C Rubin, Y AF Zimmerman, DA de Marsily, G Gotway, CA Marietta, MG Axness, CL Beauheim, RL Bras, RL Carrera, J Dagan, G Davies, PB Gallegos, DP Galli, A Gomez-Hernandez, J Grindrod, P Gutjahr, AL Kitanidis, PK Lavenue, AM McLaughlin, D Neuman, SP RamaRao, BS Ravenne, C Rubin, Y TI A comparison of seven geostatistically based inverse approaches to estimate transmissivities for modeling advective transport by groundwater flow SO WATER RESOURCES RESEARCH LA English DT Article ID HETEROGENEOUS POROUS-MEDIA; STEADY-STATE CONDITIONS; PARAMETER-IDENTIFICATION; PRIOR INFORMATION; STOCHASTIC IDENTIFICATION; HYDRAULIC CONDUCTIVITY; ASSESSING RELIABILITY; AQUIFER PARAMETERS; NUMERICAL-MODELS; UNCERTAINTY AB This paper describes the first major attempt to compare seven different inverse approaches for identifying aquifer transmissivity. The ultimate objective was to determine which of several geostatistical inverse techniques is better suited for making probabilistic forecasts of the potential transport of solutes in an aquifer where spatial variability and uncertainty in hydrogeologic properties are significant. Seven geostatistical methods (fast Fourier transform (FF), fractal simulation (FS), linearized cokriging (LC), linearized semianalytical (LS), maximum likelihood (ML), pilot point (PP), and sequential self-calibration (SS)) were compared on four synthetic data sets. Each data set had specific features meeting (or not) classical assumptions about stationarity, amenability to a geostatistical description, etc. The comparison of the outcome of the methods is based on the prediction of travel times and travel paths taken by conservative solutes migrating in the aquifer for a distance of 5 km. Four of the methods, LS, ML, PP, and SS, were identified as being approximately equivalent for the specific problems considered. The magnitude of the variance of the transmissivity fields, which went as high as 10 times the generally accepted range for linearized approaches, was not a problem for the linearized methods when applied to stationary fields; that is, their inverse solutions and travel time predictions were as accurate as those of the nonlinear methods. Nonstationarity of the "true" transmissivity field, or the presence of "anomalies" such as high-permeability fracture zones was, however, more of a problem for the linearized methods. The importance of the proper selection of the semivariogram of the log(10) (T) field (or the ability of the method to optimize this variogram iteratively) was found to have a significant impact on the accuracy and precision of the travel time predictions. Use of additional transient information from pumping tests did not result in major changes in the outcome. While the methods differ in their underlying theory, and the codes developed to implement the theories were limited to varying degrees, the most important factor for achieving a successful solution was the time and experience devoted by the user of the method. C1 GRAM Inc, Albuquerque, NM 87112 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. MIT, Dept Civil Engn, Water Resources & Environm Engn Div, Cambridge, MA 02139 USA. Univ Politecn Cataluna, ETSI Caminos, E-08034 Barcelona, Spain. Tel Aviv Univ, Dept Fluid Mech & Heat Transfer, IL-69978 Tel Aviv, Israel. Univ Paris 06, Lab Geol Appl, F-75230 Paris 05, France. Ecole Mines, Ctr Geostat, F-77035 Fontainebleau, France. Univ Politecn Valencia, Dept Ingn Hidraul & Medio Ambiente, E-46071 Valencia, Spain. Ctr Dis Control & Prevent, Natl Ctr Environm Hlth, Atlanta, GA 30333 USA. Quantisci Ltd, Henley On Thames RG9 1AT, Oxon, England. New Mexico Inst Min & Technol, Dept Math, Socorro, NM 87801 USA. Stanford Univ, Dept Civil Engn, Terman Engn Ctr, Stanford, CA 94305 USA. Duke Engn & Serv Inc, Austin, TX 78758 USA. MIT, Cambridge, MA 02139 USA. Univ Arizona, Dept Hydrol & Water Resources, Coll Engn & Mines, Tucson, AZ 85721 USA. Inst Francais Petr, F-92506 Rueil Malmaison, France. Univ Calif Berkeley, Dept Civil Engn, Berkeley, CA 94720 USA. GRAM Inc, Albuquerque, NM 87112 USA. RP Zimmerman, DA (reprint author), GRAM Inc, 8500 Menaul Blvd NE,B-335, Albuquerque, NM 87112 USA. EM tonyz@graminc.com; gdm@ccr.jussieu.fr; cdg7@cdc.gov; mgmarie@sandia.gov; daxness@etseccpb.upc.es; rlbeauh@sandia.gov; rlbras@storm.mit.edu; carrera@etseccpb.upc.es; dagan@eng.tau.ac.il; dpgalle@sandia.gov; jaime@dihma.upv.es; peterg@quantisci.co.uk; agutjahr@nmt.edu; pkk@cive.stanford.edu; amlavenu@duke-energy.com; dennism@mit.edu; neuman@hwr.arizona.edu; bsramara@duke-energy.com; rubin@arimor.ce.berkeley.edu RI Carrera, Jesus/E-7251-2011; Gomez-Hernandez, J. Jaime/J-6315-2013 OI Gomez-Hernandez, J. Jaime/0000-0002-0720-2196 NR 76 TC 189 Z9 190 U1 4 U2 34 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1998 VL 34 IS 6 BP 1373 EP 1413 DI 10.1029/98WR00003 PG 41 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA ZQ933 UT WOS:000073917600002 ER PT J AU Zhang, DX Wallstrom, TC Winter, CL AF Zhang, DX Wallstrom, TC Winter, CL TI Stochastic analysis of steady-state unsaturated flow in heterogeneous media: Comparison of the Brooks-Corey and Gardner-Russo models SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL HYDRAULIC-PROPERTIES; ANISOTROPIC POROUS FORMATIONS; VARIABLY SATURATED SOILS; SOLUTE TRANSPORT; VELOCITY COVARIANCE; PARAMETER-ESTIMATION; FIELD-SCALE; MACRODISPERSION; DISPERSION AB Existing stochastic models of unsaturated flow and transport are usually developed using the simple Gardner-Russo constitutive relationship though it is generally accepted that the more complex van Genuchten and Brooks-Corey relationships may perform better in describing experimental data. In this paper, we develop first-order stochastic models for gravity-dominated flow in second-order stationary media with both the Brooks-Corey and the Gardner-Russo constitutive relationships. These models also account for the spatial variability in effective water content, while the spatial variability is generally neglected in most existing stochastic models. Analytical solutions are obtained for the case of one-dimensional gravity-dominated flow. On the basis of the solutions, we illustrate the differences between results from these two constitutive models through some one-dimensional examples. It is found that the impacts of the constitutive models on the statistical moments of suction head, effective water content, unsaturated hydraulic conductivity, and velocity depend on the saturation ranges. For example, the mean head and the mean effective water content for the Brooks-Corey model differ in a great manner with their counterparts for the Gardner-Russo model near the dry and wet limits while the differences are small at the intermediate range of saturation. This finding is confirmed with some two-dimensional examples. It:is also found that the Brook-Corey model has certain advantages over the Gardner-Russo model in analyzing unsaturated flow in heterogeneous media. For example, the stochastic model developed based on the Brooks-Corey function requires the coefficient of variation of head and soil parameter "alpha(BC)" to be small (much less than 1), whereas that based on the Gardner-Russo function assumes the one-point cross covariance of head and alpha(GR) to be small (much less than 1). Illustrative examples reveal that the latter condition may be violated because the one-point covariance is found to increase rapidly to beyond unity as the soil becomes dry, whereas the former may be readily satisfied. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp, Los Alamos, NM 87545 USA. RP Zhang, DX (reprint author), Univ Calif Los Alamos Natl Lab, Geoanal Grp, EES-5,MS-F665, Los Alamos, NM 87545 USA. RI Zhang, Dongxiao/D-5289-2009; Winter, C. Larrabee/D-3918-2013 OI Zhang, Dongxiao/0000-0001-6930-5994; NR 34 TC 33 Z9 35 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1998 VL 34 IS 6 BP 1437 EP 1449 DI 10.1029/98WR00317 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA ZQ933 UT WOS:000073917600005 ER PT J AU Babu, SS Goodwin, GM Rohde, RJ Sielen, B AF Babu, SS Goodwin, GM Rohde, RJ Sielen, B TI Effect of boron on the microstructure of low-carbon steel resistance seam welds SO WELDING JOURNAL LA English DT Article DE resistance seam welds; low-carbon steel; decomposition kinetics; austenite; ferrite; boron; time-temperature-transformation diagrams AB Small levels of boron (20-40 wt ppm) in steel were found to have a large influence on the microstructure and hardness of resistance seam welds. The decomposition kinetics of austenite to ferrite were retarded and resulted in the formation of bainitic and martensitic microstructures in the weld metal. The welds with low and high boron concentrations showed large differences in hardness. This microstructure development is in agreement with theoretical calculations of time-temperature-transformation diagrams. This work stresses the importance of considering boron levels in steels on the weld properties. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Waukesha Elect Syst, Waukesha, WI USA. RP Babu, SS (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Babu, Sudarsanam/D-1694-2010 OI Babu, Sudarsanam/0000-0002-3531-2579 NR 10 TC 4 Z9 4 U1 1 U2 3 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 USA SN 0043-2296 J9 WELD J JI Weld. J. PD JUN PY 1998 VL 77 IS 6 BP 249S EP 253S PG 5 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA ZT397 UT WOS:000074081400027 ER PT J AU McCarron, JK McLeod, KW Conner, WH AF McCarron, JK McLeod, KW Conner, WH TI Flood and salinity stress of wetland woody species, buttonbush (Cephalanthus occidentalis) and swamp Tupelo (Nyssa sylvatica var. biflora) SO WETLANDS LA English DT Article DE buttonbush; swamp tupelo; photosynthesis; salinity; water relations; storm surge ID SEA-LEVEL RISE; NORTH-CAROLINA; GROWTH; ADAPTATIONS; SEEDLINGS; SURVIVAL AB Buttonbush (Cephalanthus occidentalis) and swamp tupelo (Nyssa sylvatica var, blflora) seedlings were exposed to flooding and salinity conditions simulating the chronic exposure of sea-level rise and the acute exposure of hurricane storm surge. Chronically exposed seedlings were either watered or hooded with 0, 2, or 10 ppt salinity. Those in the acute experiment were watered or flooded with freshwater until exposed to a 21-ppt salinity surge for 48 hours. Freshwater flooding reduced photosynthesis (A), water pressure potential (Psi), height, and stem and root biomass for swamp tupelo while biomass of buttonbush roots decreased and stem increased. Chronic watering with 2 ppt salinity reduced height, basal diameter, and stem and root biomass for swamp tupelo but did not significantly affect buttonbush. Both species were negatively affected by watering with 10 ppt salinity, with total mortality of swamp tupelo. Flooding with 2 ppt salinity also caused a 100% mortality for swamp tupelo. All buttonbush seedlings survived with reduced A, Psi, and stem and root biomass. Plants chronically flooded with 10 ppt salinity were more affected, with drastically decreased A, stomatal conductance (g(s)), and Psi within the first day of treatment and all dying within three weeks. Watering with 21 ppt salinity reduced A and g(s) of both species during the second day of the surge, but buttonbush recovered within the next 20 days. Flooding with 21-ppt saline water also greatly impacted buttonbush, which did not recover as when watered with 21 ppt salinity. Swamp tupelo was already stressed due to flooding and showed no further reduction in A or g( s) due to the 21-ppt salinity flood surge. Buttonbush seedlings were more tolerant of salinity and flooding conditions than swamp tupelo seedlings, although it is unlikely that either species could survive long-term exposure to 10-ppt salinity flooding. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP McCarron, JK (reprint author), Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. NR 33 TC 13 Z9 15 U1 1 U2 7 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0277-5212 J9 WETLANDS JI Wetlands PD JUN PY 1998 VL 18 IS 2 BP 165 EP 175 PG 11 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA ZV104 UT WOS:000074269500001 ER PT J AU Leary, AW Mazaika, R Bechard, MJ AF Leary, AW Mazaika, R Bechard, MJ TI Factors affecting the size of Ferruginous Hawk home ranges SO WILSON BULLETIN LA English DT Article AB We used radio-telemetry to track movements of seven adult male Ferruginous Hawks (Buteo regalis) in southcentral Washington. Home range size was estimated for each male using minimum convex polygon, harmonic mean, adaptive kernel, and fixed kernel-based methods. Minimum convex polygon and harmonic mean home ranges were significantly larger than those previously reported for Ferruginous Hawks. Home ranges varied substantially among males (mean = 90.3 km(2), range = 17.7-136.4 km(2)). There was no relationship between home range size and brood size; however, there was a significant relationship (r(2) = 0.964, P = 0.018) between home range size and the distance from the nest site to the nearest irrigated agricultural field where some males hunted. Kernel-based estimates showed two distinct core areas for most males, one around the nest and a second in the agricultural fields where they hunted. C1 Boise State Univ, Dept Biol, Raptor Res Ctr, Boise, ID 83725 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Leary, AW (reprint author), Missouri Natl Guard, NGMO EMN, 2302 Militia Dr, Jefferson City, MO 65101 USA. NR 36 TC 17 Z9 17 U1 1 U2 13 PU WILSON ORNITHOLOGICAL SOC PI ANN ARBOR PA MUSEUM OF ZOOLOGY UNIV MICHIGAN, ANN ARBOR, MI 48109 USA SN 0043-5643 J9 WILSON BULL JI Wilson Bull. PD JUN PY 1998 VL 110 IS 2 BP 198 EP 205 PG 8 WC Ornithology SC Zoology GA ZY281 UT WOS:000074604400005 ER PT J AU Bartels, MJ McNett, DA Timchalk, C Mendrala, AL Christenson, WR Sangha, GK Brzak, KA Shabrang, SN AF Bartels, MJ McNett, DA Timchalk, C Mendrala, AL Christenson, WR Sangha, GK Brzak, KA Shabrang, SN TI Comparative metabolism of ortho-phenylphenol in mouse, rat and man SO XENOBIOTICA LA English DT Article ID URINARY-BLADDER; F344 RATS; SODIUM AB 1. Ortho-phenylphenol (OPP) was well absorbed in the male B6C3F1 mouse, with 84 and 98% of the administered radioactivity recovered in the 0-48-h urine of animals administered a single oral dose of 15 or 800 mg/kg respectively. High absorption and rapid elimination were also seen in the female and male F344 rat with 86 and 89 % respectively of a single oral dose (27-28 mg/kg) found in the urine in 24 h. OPP was also rapidly eliminated from human volunteers following dermal exposure for 8 h (0.006 mg/kg), with 99 % of the absorbed dose in the urine in 48 h. 2. Sulphation of OPP was found to be the major metabolic pathway at low doses in all three species, accounting for 57, 82 and 69 % of the urinary radioactivity in the male mouse (15mg/kg, p.o.), male rat (28 mg/kg, p.o.) and male human volunteers (0 006 mg/kg, dermal). OPP-glucuronide was also present in all species, representing 29, 7 and 4 % of the total urinary metabolites in the low dose groups of mouse, rat and human volunteers respectively. 3. Conjugates of 2-phenylhydroquinone (PHQ) in these single-dose studies accounted for 12, 5 and 15% of the dose in mouse, rat and human, respectively. Little or no free OPP was found in any species. No free PHQ or PBQ was found in the mouse, rat or human (LOD = 0.1-0.6 %). 4. A novel metabolite, the sulphate conjugate of 2,4'-dihydroxybiphenyl, was identified in rat and man, comprising 3 and 13 % of the low dose respectively. 5. Dose-dependent shifts in metabolism were seen in the mouse for conjugation of parent OPP, indicating saturation of the sulphation pathway. Dose-dependent increases in total PHQ were also observed in mouse. 6. This study was initiated to elucidate a mechanistic basis for the difference in carcinogenic potential for OPP between rat and mouse. However, the minor differences seen in the metabolism of OPP in these two species do not appear to account for the differences in urinary bladder toxicity and tumour response between mouse and rat. C1 Dow Chem Co USA, Hlth & Environm Res Lab, Midland, MI 48674 USA. Pacific NW Lab, Richland, WA USA. Bayer Corp, Div Agr, Toxicol Lab, Stilwell, KS 66085 USA. RP Bartels, MJ (reprint author), Dow Chem Co USA, Hlth & Environm Res Lab, 1803 Bldg, Midland, MI 48674 USA. NR 19 TC 14 Z9 14 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0049-8254 J9 XENOBIOTICA JI Xenobiotica PD JUN PY 1998 VL 28 IS 6 BP 579 EP 594 PG 16 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA ZY298 UT WOS:000074606100005 PM 9667081 ER PT J AU Asmussen, B Strzelczyk, M Press, W Larese, JZ AF Asmussen, B Strzelczyk, M Press, W Larese, JZ TI Low coverage structure of tetramethyltin adsorbed on graphite SO SURFACE SCIENCE LA English DT Article DE diffraction; neutron scattering; phase diagram; physical adsorption; polycrystalline surfaces; structure; tetramethyltin [TMSn,Sn(CH3)(4)]; X-ray scattering ID PHASE-DIAGRAM; TRANSITIONS; DIFFRACTION; PLANES AB Submonolayers of protonated and deuterated tetramethyltin on exfoliated graphite have been investigated with both X-ray and neutron diffraction. At coverages theta < 0.8 ML, Sn(CH3)(4) on graphite forms a unit cell containing seven molecules in the tripod-down configuration. Slight differences between the lattice parameters of the protonated and the deuterated adsorbate were found [a= 6.75 Angstrom, b = 44.2 Angstrom, gamma =113.5 degrees for Sn(CH3)(4) and a = 6.74 Angstrom, b = 44.5 Angstrom, gamma =114.0 degrees in the case of Sn(CD3)(4)]. The adsorbate structure is incommensurate with the graphite substrate and has light domain walls. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Kiel, Inst Expt Phys, D-24098 Kiel, Germany. Brookhaven Natl Lab, Dept Chem, Long Isl, NY USA. RP Strzelczyk, M (reprint author), Univ Kiel, Inst Expt Phys, Leibnizstr 19, D-24098 Kiel, Germany. NR 18 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 31 PY 1998 VL 406 IS 1-3 BP 138 EP 148 DI 10.1016/S0039-6028(98)00106-X PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX832 UT WOS:000074559900021 ER PT J AU Zhang, CM Bartelt, MC Wen, JM Jenks, CJ Evans, JW Thiel, PA AF Zhang, CM Bartelt, MC Wen, JM Jenks, CJ Evans, JW Thiel, PA TI Submonolayer island formation and the onset of multilayer growth during Ag/Ag(100) homoepitaxy SO SURFACE SCIENCE LA English DT Article DE epitaxy; kinetic roughening; nucleation and growth; scanning tunneling microscopy; silver; surface diffusion ID ENERGY-ELECTRON-DIFFRACTION; BY-LAYER GROWTH; MOLECULAR-BEAM EPITAXY; CLUSTER DIFFUSION; SELF-DIFFUSION; THIN-FILMS; AG; NUCLEATION; AG(100); MORPHOLOGY AB Results from a scanning tunneling microscopy study are presented for the initial stags of Ag/Ag(100) homoepitaxy, and behavior is analyzed via Monte Carlo simulations of an appropriate lattice-gas model. Submonolayer nucleation and growth of two-dimensional islands is examined for substrate temperatures, T, between 295 and 370 K. The variation with Bur of the mean island density, N-av, reveals that island formation is effectively irreversible at 295 K, and leads to an estimate of 0.38 eV for the terrace diffusion barrier (using an attempt frequency of 10(13)/s). The variation of N-av with T reveals a transition to reversible island formation at around 320 K. This transition temperature (and the T-dependence of N-av) are used to extract an effective value of 0.3 eV for the bond energy of an adsorbed dimer, assuming nearest-neighbor pairwise-additive interactions between adsorbed atoms. We indicate how the actual dimer bond energy could differ, e.g. in the presence of biased diffusion of separated adatom pairs which enhances their recombination. and thus increases effective dimer stability. The onset of multilayer growth, and specifically the formation of second-layer islands, is examined at 295 K to assess the degree of interlayer transport. Comparison with simulations yields an estimate of 30 meV for the effective value of an additional step-edge barrier (using an attempt frequency of 10(13)/s). Using this result, subsequent multilayer kinetic roughening is predicted, consistent with experimental observations. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Dept Math, IPRT, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Thiel, PA (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 88 TC 48 Z9 49 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 31 PY 1998 VL 406 IS 1-3 BP 178 EP 193 DI 10.1016/S0039-6028(98)00109-5 PG 16 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX832 UT WOS:000074559900024 ER PT J AU Jellinek, J Srinivas, S Fantucci, P AF Jellinek, J Srinivas, S Fantucci, P TI Ab initio Monte Carlo: application to Li(8) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; MOLECULAR-DYNAMICS; ELECTRON CORRELATION; METAL-CLUSTERS; ENERGY; SIMULATIONS; BEHAVIOR; WALKING AB An ab initio-based Monte Carlo scheme is developed and implemented to investigate structural and thermal properties of lithium clusters. The scheme combines a hybrid Hartree-Fock/density functional electronic structure treatment with a Monte Carlo sampling of the nuclear configuration space. Structural forms (isomers) of the Li(8 )cluster are obtained and its thermal properties are analyzed. The analysis is carried out in terms of probability distributions of the cluster potential (configurational) energy, average potential energy and configurational heat capacity, all considered as a function of the cluster temperature. An estimate of the temperature characterizing the onset of isomer 'coexistence' in L(8) is given. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Ctr CNR, Dipartimento Chim Inorgan Metallorgan & Analit, I-20133 Milan, Italy. RP Jellinek, J (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 35 TC 20 Z9 20 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 29 PY 1998 VL 288 IS 5-6 BP 705 EP 713 DI 10.1016/S0009-2614(98)00378-9 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZV253 UT WOS:000074285700016 ER PT J AU Poluektov, OG Doubinski, AA AF Poluektov, OG Doubinski, AA TI Two-dimensional high-field electron spin echo spectroscopy of nitroxide spin probes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULAR MOTIONS; 95 GHZ; EPR AB Relaxation of a highly asymmetric nitroxide spin probe in the frozen toluene solution was studied below 'rigid limit' temperatures by means of two-dimensional high-field electron spin echo spectroscopy. It was shown that observed relaxation cannot be explained by reorientation motion of the nitroxide. A model is proposed in which an asymmetric relaxation is due to the modulation of the g-values caused by the fluctuations of the environment of the nitroxide. This model qualitatively agrees with the relaxation observed. The estimation of the correlation times of such modulation is done. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NN Semenov Chem Phys Inst, Moscow 117977, Russia. RP Poluektov, OG (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 29 PY 1998 VL 288 IS 5-6 BP 841 EP 846 DI 10.1016/S0009-2614(98)00374-1 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZV253 UT WOS:000074285700037 ER PT J AU Zeng, LM Franzen, HF AF Zeng, LM Franzen, HF TI The crystal structure of HfZrP SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE hafnium; phosphorus; zirconium; crystal structure AB The crystal structure of HfZrP has been determined using single crystal X-ray diffraction data. This compound crystallizes in the orthorhombic space group Cmmm (No.65), with a=19.004(3), b=29.372(4), c=3.565(1) Angstrom and the Zr2P structure type. The Hf and Zr atoms are disordered on one site with total occupancy of 1.0. X-ray powder patterns indicate that (HfxZr1-x)(2) P alloys consist of single phase (Zr2P-type),two phases and single phase (Hf2P-type) corresponding to 0 less than or equal to x less than or equal to 0.5, 0.5Nd2M17-type (metastable) phase transition and the formation of the Nd2M14B phase, shifting them to higher temperatures. The transformation behavior of the alloys as a function of Cr content ultimately controls the phase constitution, phase chemistry and the grain size, which in turn control the room-temperature hysteretic magnetic properties. (C) 1998 Elsevier Science S.A. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. Magnequench Int Inc, MQI, Anderson, IN 46013 USA. RP Lewis, LH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. NR 30 TC 15 Z9 19 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 29 PY 1998 VL 270 IS 1-2 BP 265 EP 274 DI 10.1016/S0925-8388(98)00529-5 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA ZY389 UT WOS:000074616400047 ER PT J AU Gerberding, SJ Byers, CH AF Gerberding, SJ Byers, CH TI Preparative ion-exchange chromatography of proteins from dairy whey SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE preparative chromatography; proteins; whey AB A preparative-scale ion-exchange chromatographic process is described for the separation of the four major proteins and lactose from sweet dairy whey. Experiments using a commercial anion-exchange resin were carried out to determine the optimum conditions for initially separating the proteins alpha-lactalbumin, beta-lactoglobulin, bovine serum albumin, immunoglobulin G and lactose from a sweet dairy whey mixture. The separation was accomplished with simultaneous step elution changes in salt concentration and pH. It was found that the anion-exchange step was most effective in separating beta-lactoglobulin from the feed mixture. Following the anion-exchange separation, its breakthrough curve was processed using a commercial cation-exchangre resin to further recover the valuable immunoglobulin G. The whey output from an east Tennessee cheese manufacturer was used as a feedstream for the preparative scale experiments and as a reference in scaling to an economically optimized production level operation. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Gerberding, SJ (reprint author), 1912 Kevin Ave, Elgin, IL 60123 USA. NR 12 TC 45 Z9 46 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 29 PY 1998 VL 808 IS 1-2 BP 141 EP 151 DI 10.1016/S0021-9673(98)00103-4 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZT892 UT WOS:000074138500015 PM 9652116 ER PT J AU Dupas-Bruzek, C Sharp, TG Rubie, DC Durham, WB AF Dupas-Bruzek, C Sharp, TG Rubie, DC Durham, WB TI Mechanisms of transformation and deformation in Mg1.8Fe0.2SiO4 olivine and wadsleyite under non-hydrostatic stress SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article DE olivine; wadsleyite; ringwoodite; transition zone; phase transformations; deformation mechanism ID BETA-PHASE-TRANSFORMATION; SUBDUCTION ZONE CONDITIONS; DEEP-FOCUS EARTHQUAKES; MANTLE TRANSITION ZONE; HIGH-TEMPERATURE CREEP; X-RAY-MICROANALYSIS; SPINEL TRANSFORMATION; SINGLE-CRYSTALS; DISLOCATION-STRUCTURES; ELECTRON-MICROSCOPY AB We have studied the effect of non-hydrostatic stress on the mechanisms of the olivine-wadsleyite-ringwoodite (alpha-beta-gamma) phase transformations and deformation mechanisms of olivine and wadsleyite at high pressure. Experiments were performed at 900 degrees C in the beta-stability field (15 GPa) for 0.5 h and in the beta + gamma stability field (16 GPa) for 11 h using a multianvil apparatus with San Carlos olivine as the starting material, A sample assembly designed to produce non-hydrostatic stress was used. The deformed samples have been characterised using optical and transmission electron microscopy, Remnant olivine contains high densities of mostly c dislocations and deformation occurs by dislocation glide involving the slip systems (010)[001] and (100)[001]. In wadsleyite, dislocations are in a climb, configuration, which suggests that self diffusion of Si and/or O is much faster in wadsleyite than in olivine at similar to 900 degrees C. Wadsleyite also contains (010)(beta) stacking faults which are interpreted to be growth defects that anneal out with time. During the olivine-wadsleyite transformation, non-hydrostatic stress results in anisotropic reaction textures. Wadsleyite nucleates preferentially on olivine grain boundaries that are oriented at a high angle to the direction of principal compressive stress and/or the growth of wadsleyite occurs preferentially in this direction. Wadsleyite transforms to ringwoodite by two competing mechanisms: (i) coherent intracrystalline nucleation on a dislocations, probably where they intersect (010)(beta) stacking faults, and (ii) partially-coherent nucleation at wadsleyite grain boundaries. Non-hydrostatic stress enhances transformation rates by increasing the density of dislocations which act as nucleation sites for ringwoodite. Although the samples were partially reacted under non-hydrostatic stress, there is no evidence for transformational faulting. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Rubie, DC (reprint author), Univ Bayreuth, Bayer Geoinst, POB 101251, D-95440 Bayreuth, Germany. NR 69 TC 35 Z9 37 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD MAY 29 PY 1998 VL 108 IS 1 BP 33 EP 48 DI 10.1016/S0031-9201(98)00086-7 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZW837 UT WOS:000074453300003 ER PT J AU Nortershauser, W Trautmann, N Wendt, K Bushaw, BA AF Nortershauser, W Trautmann, N Wendt, K Bushaw, BA TI Isotope shifts and hyperfine structure in the 4s(2) S-1(0)-> 4s4p P-1(1)-> 4s4d D-1(2) transitions of stable calcium isotopes and calcium-41 SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article DE calcium; resonance ionization mass spectrometry; isotope shifts; hyperfine structure; high resolution laser spectroscopy ID IONIZATION SPECTROSCOPY; NATURALLY ABUNDANT; ENERGY-LEVELS; CA ISOTOPES; LASER; CA-41 AB Isotope shifts and hyperfine structure in the 4s(2) S-1(0) --> 4s4p P-1(1) and 4s(2) S-1(0) --> 4s3d D-1(2) transitions of calcium have been measured with high-precision laser spectroscopy. Calcium atoms in an atomic beam were excited with single-frequency cw dye and titanium sapphire lasers and then photoionized with the 363.8 nm or 514.5 nm line of an argon ion laser. The resulting ions were analyzed and detected with a quadrupole mass spectrometer. Isotope shifts for all stable calcium isotopes and the radionuclide Ca-41 have been measured in both transitions. The corresponding field shift and specific mass shift coefficients as well as hyperfine structure constants for the isotopes Ca-41,Ca-43 have been derived. The results are compared with previous work and values for Ca-41,Ca-43,Ca-46 in the 4s4d D-1(2) State are reported for the first time. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Univ Mainz, Inst Kernchem, D-55099 Mainz, Germany. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Nortershauser, W (reprint author), Univ Mainz, Inst Phys, D-55099 Mainz, Germany. RI Wendt, Klaus/D-7306-2011; Nortershauser, Wilfried/A-6671-2013 OI Wendt, Klaus/0000-0002-9033-9336; Nortershauser, Wilfried/0000-0001-7432-3687 NR 39 TC 41 Z9 41 U1 2 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD MAY 29 PY 1998 VL 53 IS 5 BP 709 EP 721 DI 10.1016/S0584-8547(98)00108-6 PG 13 WC Spectroscopy SC Spectroscopy GA ZX445 UT WOS:000074516600005 ER PT J AU Mao, XL Borisov, OV Russo, RE AF Mao, XL Borisov, OV Russo, RE TI Enhancements in laser ablation inductively coupled plasma-atomic emission spectrometry based on laser properties and ambient environment SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article DE laser ablation; ablated material; Cu; inductively coupled plasma-atomic emission spectrometry (ICP-AES) ID MASS-SPECTROMETRY; SOLID MATERIALS; WAVELENGTH DEPENDENCE; CONTROLLED-ATMOSPHERE; BASIC INVESTIGATIONS; MICROANALYSIS; SAMPLES; PLUMES; VAPORIZATION; FLUORESCENCE AB Analytical performance of laser ablation inductively coupled plasma-atomic emission spectrometry (ICP-AES) depends critically on the interaction between the laser light and the sample. The analyte emission line intensity in ICP-AES depends on the quantity of mass ablated. The effect of laser parameters (wavelength, pulse duration, and power density) was investigated for increasing the quantity of ablated mass. For fixed laser beam energy, the ablated mass can change 2 to 3 orders of magnitude by changing the laser beam spot size on the sample. The ablated mass quantity also depends on laser pulse duration and wavelength; and on ambient gas in the sample chamber. The shorter the pulse duration and wavelength, the higher the quantity of ablated mass. By using He in the chamber, the amount of mass increases by a factor of 2 for 30 ns excimer laser ablation and by an order of magnitude for ps-laser ablation. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 39 TC 34 Z9 36 U1 2 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD MAY 29 PY 1998 VL 53 IS 5 BP 731 EP 739 DI 10.1016/S0584-8547(98)00106-2 PG 9 WC Spectroscopy SC Spectroscopy GA ZX445 UT WOS:000074516600007 ER PT J AU Milanovich, N Ratsep, M Reinot, T Hayes, JM Small, GJ AF Milanovich, N Ratsep, M Reinot, T Hayes, JM Small, GJ TI Stark hole burning of aluminum phthalocyanine tetrasulfonate in normal and cancer cells SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID GLASSY FILMS; WATER AB The results of Stark hole burning of aluminum phthalocyanine tetrasulfonate (APT) in MCF-10F (normal) and MCF-7 (cancer) cells are reported. Hole broadening was observed far zero-phonon holes (ZPH) for both cell lines when laser polarization was parallel and perpendicular to an applied electric (Stark) field. Changes in dipole moment suggest that dye molecules are located near the cell membrane and, in normal cells, experience some degree of ordering not found in the cancer cells. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Hayes, JM (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. NR 18 TC 10 Z9 10 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 28 PY 1998 VL 102 IS 22 BP 4265 EP 4268 DI 10.1021/jp981219r PG 4 WC Chemistry, Physical SC Chemistry GA ZT268 UT WOS:000074067600004 ER PT J AU Tannian, BE Popple, RA Dunning, FB Yoshida, S Reinhold, CO Burgdorfer, J AF Tannian, BE Popple, RA Dunning, FB Yoshida, S Reinhold, CO Burgdorfer, J TI Ionization of Rydberg atoms by half-cycle pulses: effect of pulse shape and rise time SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID COUPLED-STATE CALCULATIONS; FIELD-IONIZATION; SCHRODINGER-EQUATION; SCATTERING AB The ionization of potassium np Rydberg atoms with n similar to 388 by pulsed unidirectional electric fields, termed half-cycle pulses (HCPs), with various well characterized shapes (rectangular, triangular and sawtooth) and durations T-p comparable to the classical electron orbital period T-n is investigated. The experimental results are compared with classical trajectory Monte Carlo (CTMC) simulations and the classically scaled results of quantum calculations undertaken at n = 5. The data show chat in the intermediate regime, T-p greater than or similar to T-n, the threshold field for ionization becomes sensitive to the shape and rise time of the HCP, increasing with increasing rise time. For each pulse shape, the agreement between the experimental measurements and both the CTMC and quantum calculations is very good. C1 Rice Univ, Dept Phys, Houston, TX 77251 USA. Rice Univ, Rice Quantum Inst, Houston, TX 77251 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Tannian, BE (reprint author), Rice Univ, Dept Phys, POB 1892, Houston, TX 77251 USA. OI Reinhold, Carlos/0000-0003-0100-4962 NR 21 TC 3 Z9 3 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 1998 VL 31 IS 10 BP L455 EP L460 DI 10.1088/0953-4075/31/10/003 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU423 UT WOS:000074195600003 ER PT J AU Borovsky, JE AF Borovsky, JE TI Aurorae - Still in the dark SO NATURE LA English DT Editorial Material ID FIELD; MAGNETOSPHERE; IONOSPHERE; CURRENTS; ARCS C1 Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. RP Borovsky, JE (reprint author), Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, POB 1663, Los Alamos, NM 87545 USA. NR 13 TC 5 Z9 5 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 28 PY 1998 VL 393 IS 6683 BP 312 EP 313 DI 10.1038/30616 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ593 UT WOS:000073883600028 ER PT J AU Jenkins, DG Hibbert, IM Parry, CM Wadsworth, R Fossan, DB Lane, GJ Sears, JM Smith, JF Clark, RM Krucken, R Lee, IY Macchiavelli, AO Janzen, VP Cameron, J Frauendorf, S AF Jenkins, DG Hibbert, IM Parry, CM Wadsworth, R Fossan, DB Lane, GJ Sears, JM Smith, JF Clark, RM Krucken, R Lee, IY Macchiavelli, AO Janzen, VP Cameron, J Frauendorf, S TI Magnetic rotation in Sn-106 and Sn-108 SO PHYSICS LETTERS B LA English DT Article ID SHEARS BANDS; TERMINATION AB The nuclei Sn-106 and Sn-108 have been populated using the Fe-54(Ni-58,alpha 2p) and Fe-54(Ni-58,4p) reactions, respectively, at a beam energy of 243 MeV and the gamma rays have been detected using the Gammasphere array. Two "rotation-like" structures consisting of magnetic dipole transitions have been observed in each of the nuclei. The bands can be interpreted, using the Tilted Axis Cranking model, as examples of magnetic rotation. The calculations show excellent agreement with the data for Sn-108. However, for the lighter isotope, Sn-106, the model is unable to reproduce the experimental B(M1)/B(E2) ratios. Reasons for this discrepancy are discussed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. AECL Res, Chalk River Labs, Chalk River, ON K0J 1J0, Canada. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Rossendorf Inc, Forschungszentrum Rossendorf EV, D-01314 Dresden, Germany. RP Jenkins, DG (reprint author), Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. RI Lane, Gregory/A-7570-2011; Kruecken, Reiner/A-1640-2013 OI Lane, Gregory/0000-0003-2244-182X; Kruecken, Reiner/0000-0002-2755-8042 NR 18 TC 43 Z9 44 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 28 PY 1998 VL 428 IS 1-2 BP 23 EP 30 DI 10.1016/S0370-2693(98)00384-0 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZY402 UT WOS:000074617700005 ER PT J AU Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Boutigny, D Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chen, M Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Drago, E Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, F Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gau, SS Gentile, S Gerald, J Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hirschfelder, J van Hoek, WC Hofer, H Hoorani, H Hou, SR Hu, G Innocente, V Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Leggett, C Le Goff, JM Leiste, R Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohman, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Migani, D Mihul, A van Mil, AJW Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Moulik, T Mount, R Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palit, S Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Rind, O Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Sauvage, G Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Schneegans, M Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Soulimov, V Smith, B Spillantini, P Steuer, M Stickland, DP Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Vlachos, S Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP AF Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Boutigny, D Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chen, M Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Drago, E Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, F Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gau, SS Gentile, S Gerald, J Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hirschfelder, J van Hoek, WC Hofer, H Hoorani, H Hou, SR Hu, G Innocente, V Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Leggett, C Le Goff, JM Leiste, R Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohman, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Migani, D Mihul, A van Mil, AJW Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Moulik, T Mount, R Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palit, S Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Rind, O Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Sauvage, G Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Schneegans, M Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Soulimov, V Smith, B Spillantini, P Steuer, M Stickland, DP Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Vlachos, S Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP CA L3 Collaboration TI Angular multiplicity fluctuations in hadronic Z decays and comparison to QCD models and analytical calculations SO PHYSICS LETTERS B LA English DT Article ID RADIATIVE 2-JET EVENTS; HIGH-ENERGY COLLISIONS; BUNCHING-PARAMETER; E+E ANNIHILATION; 3-JET EVENTS; JETS; INTERMITTENCY; DETECTOR; CONSTRUCTION; SIMULATION AB Local multiplicity fluctuations in angular phase space intervals are studied using factorial moments measured in hadronic events at root s similar or equal to 91.2 GeV, which were collected by the L3 detector at LEP. Parton shower Monte Carlo programs agree well with the data. On the other hand, first-order QCD calculations in the Double Leading Log Approximation and the Modified Leading Log Approximation are found to deviate significantly from the data, (C) 1998 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. NIKHEF H, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. CNRS, IN2P3, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. INFN, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest, Hungary. MIT, Cambridge, MA 02139 USA. Univ Florence, I-50125 Florence, Italy. INFN, Sez Firenze, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. World Lab, FBLJA Project, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Chinese Univ Sci & Technol, USTC, Hefei 230029, Anhui, Peoples R China. SEFT, Res Inst High Energy Phys, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Univ Lecce, I-73100 Lecce, Italy. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Claude Bernard, Inst Phys Nucl Lyon, IN2P3, CNRS, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Inst Theoret & Expt Phys, Moscow 117259, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Roma La Sapienza, I-00185 Rome, Italy. INFN, Sez Roma, I-00185 Rome, Italy. Inst Phys Nucl, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. INFN, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, University, AL 35486 USA. NIKHEF H, NL-3584 CB Utrecht, Netherlands. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. Natl Tsing Hua Univ, Dept Phys, Hsinchu, Taiwan. RP Acciarri, M (reprint author), Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy. RI Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Roth, Stefan/J-2757-2016; Kamyshkov, Yuri/J-7999-2016; Di Lodovico, Francesca/L-9109-2016; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014 OI Castellini, Guido/0000-0002-0177-0643; Read, Kenneth/0000-0002-3358-7667; Diemoz, Marcella/0000-0002-3810-8530; Doria, Alessandra/0000-0002-5381-2649; Sciacca, Crisostomo/0000-0002-8412-4072; Faccini, Riccardo/0000-0003-2613-5141; Bertucci, Bruna/0000-0001-7584-293X; Filthaut, Frank/0000-0003-3338-2247; Goldstein, Joel/0000-0003-1591-6014; Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Roth, Stefan/0000-0003-3616-2223; Kamyshkov, Yuri/0000-0002-3789-7152; Di Lodovico, Francesca/0000-0003-3952-2175; Longo, Egidio/0000-0001-6238-6787; Ambrosi, Giovanni/0000-0001-6977-9559; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731 NR 56 TC 15 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 28 PY 1998 VL 428 IS 1-2 BP 186 EP 196 DI 10.1016/S0370-2693(98)00386-4 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZY402 UT WOS:000074617700027 ER PT J AU Yukhimuk, V Roussel-Dupre, RA Symbalisty, EMD Taranenko, Y AF Yukhimuk, V Roussel-Dupre, RA Symbalisty, EMD Taranenko, Y TI Optical characteristics of red sprites produced by runaway air breakdown SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ELECTROSTATIC THUNDERCLOUD FIELDS; ELECTROMAGNETIC PULSES; LOWER IONOSPHERE; EXCITATION; IONIZATION; DISCHARGES; N2; MESOSPHERE; ATMOSPHERE; ELECTRONS AB The results of numerical calculations of intensity and spectra of optical emissions from red sprites produced by runaway air breakdown in the atmosphere are presented. It is shown that the optical emissions from red sprites consist of two components: (1) short-term (t approximate to 0.3-2 ms) emissions produced as a result of dissipation of an energetic electron beam in air; 2) long-term (t approximate to 2-10 ms) emissions produced by a population of low-energy electrons in an electric field. The long-term optical emissions are calculated for all low-energy electrons, including the secondary low-energy electrons produced by the relativistic electron beam, ambient background electrons, and electrons produced as a result of regular breakdown. The theoretical results are compared with observational data. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Yukhimuk, V (reprint author), Los Alamos Natl Lab, EES-8,MS D401, Los Alamos, NM 87545 USA. EM slava@lan1.gov; rroussel-dupre@lan1.gov; esymbalisty@lan1.gov; yuri@lan1.gov NR 40 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1998 VL 103 IS D10 BP 11473 EP 11482 DI 10.1029/98JD00348 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP485 UT WOS:000073758200025 ER PT J AU Borovsky, JE AF Borovsky, JE TI Lightning energetics: Estimates of energy dissipation in channels, channel radii, and channel-heating risetimes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COMMON PHYSICAL PROCESSES; RETURN STROKE MODEL; ELECTRIC-FIELD; STEPPED LEADERS; BASE CURRENT; PEAK CURRENT; THUNDERSTORMS; THUNDERCLOUD; SPEED; PROPAGATION AB In this report, several lightning-channel parameters are calculated with the aid of an electrodynamic model of lightning. The electrodynamic model describes dart leaders and return strokes as electromagnetic waves that are guided along conducting lightning channels. According to the model, electrostatic energy is delivered to the channel by a leader, where it is stored around the outside of the channel; subsequently, the return stroke dissipates this locally stored energy. In this report this lightning-energy-flow scenario is developed further. Then the energy dissipated per unit; length in lightning channels is calculated, where this quantity is now related to the linear charge density on the channel, not to the cloud-to-ground electrostatic potential difference. Energy conservation is then used to calculate the radii of lightning channels: their initial radii at the onset of return strokes and their final radii after the channels have pressure expanded. Finally, the risetimes for channel heating during return strokes are calculated by defining an energy-storage radius around the channel and by estimating the radial velocity of energy flow toward the channel during a return stroke. In three appendices, values for the linear charge densities on lightning channels are calculated, estimates of the total length of branch channels are obtained, and values for the cloud-to-ground electrostatic potential difference are estimated. C1 Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. RP Borovsky, JE (reprint author), Los Alamos Natl Lab, Space & Atmospher Sci Grp, Mail Stop D466, Los Alamos, NM 87545 USA. EM jborovsky@lan1.gov NR 96 TC 20 Z9 21 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1998 VL 103 IS D10 BP 11537 EP 11553 DI 10.1029/97JD03230 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP485 UT WOS:000073758200029 ER PT J AU Van Nguyen, T Vanderborgh, N AF Van Nguyen, T Vanderborgh, N TI The rate of isothermal hydration of polyperfluorosulfonic acid membranes SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE diffusion; water sorption and diffusion; dynamic thermogravimetric analysis; fuel cells ID WATER-UPTAKE; TRANSPORT; ION AB Water transport rates through polyperfluorosulfonic acid membranes at relatively low water content (close to the fuel cell failure mode) were investigated using dynamic thermogravimetry. A model was developed to describe water transport within the membrane during the dynamic thermogravimetry experiment. Using the model, the experimental data, and a non-linear regression technique, values for the effective diffusion coefficient of water in the Dow Chemical's experimental membrane samples of the same equivalent weight but of two different thickness, 10.16 and 17.78 mu m, were obtained for temperatures of 60 degrees C, 80 degrees C, and 90 degrees C. Results show that the effective diffusion coefficient of water in the membrane increases with water content and temperature. Values for the partition coefficient of water in these membranes at these temperatures are determined and found to be in close agreement with published values. Finally, rehydration of polyperfluorosulfonic acid membranes is found to be controlled by both the gas/solid interface and the diffusion of water into the inner structure of the membrane. (C) 1998 Elsevier Science B.V. C1 Univ Kansas, Dept Chem & Petr Engn, Lawrence, KS 66045 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Van Nguyen, T (reprint author), Univ Kansas, Dept Chem & Petr Engn, 4006 Learned Hall, Lawrence, KS 66045 USA. NR 18 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD MAY 27 PY 1998 VL 143 IS 1-2 BP 235 EP 248 DI 10.1016/S0376-7388(98)00030-1 PG 14 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA ZQ764 UT WOS:000073900700020 ER PT J AU Gosztola, D Niemczyk, MP Wasielewski, MR AF Gosztola, D Niemczyk, MP Wasielewski, MR TI Picosecond molecular switch based on bidirectional inhibition of photoinduced electron transfer using photogenerated electric fields SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SYNTHETIC MULTIPORPHYRIN ARRAYS; OPTICAL CONTROL; ACCEPTOR; DESIGN; SHIFT C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Wasielewski, MR (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 15 TC 113 Z9 118 U1 0 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 27 PY 1998 VL 120 IS 20 BP 5118 EP 5119 DI 10.1021/ja980358j PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZQ630 UT WOS:000073887300027 ER PT J AU Ontko, AC Angelici, RJ AF Ontko, AC Angelici, RJ TI Studies of the adsorption of bi- and tridentate isocyanides on gold powder SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; COORDINATION CHEMISTRY; LIGANDS; COMPLEXES; SURFACES; THIOLS; COADSORPTION; CRYSTAL AB Diffuse reflectance Fourier transform spectroscopic (DRIFTS) studies of diisocyanides [C=N-(CH2)(x)N=C, where x = 2, 4, 6, 8, and 12; m- and p-xylyl(NC)(2), xylyl = -CH2-C6H4-CH2-] and triisocyanides [1,1,1-tris(isocyanomethyl)ethane (Tripod(NC)(3)) and tris[2-isocyanoethyl]amine (Tren(NC)(3))] adsorbed on gold (Au) powder show that all of their -NC groups are coordinated to the surface. The nu(NC) values (cm(-1)) for the adsorbed ligands are similar to 2220 cm(-1), which indicates that each of the -NC groups is bound through the carbon to a single Au atom. The saturation coverages (n(1s)) for the diisocyanides decrease as the linking -(CH2)(x)-group lengthens from x = 2 to x = 12. At saturation coverage, the number of moles of -N=C groups coordinated for C-12(NC)(2) is similar to that for the monoisocyanide n-C18H37NC, whereas twice as many -NC groups are adsorbed for C-2(NC)(2) than n-C18H37NC. Qualitative kinetic measurements show that all of the monoisocyanide n-C18H37NC adsorbed on Au powder is displaced by C-4(NC)(2) within 90 min. However, only 39% of the diisocyanide m-xylyl((NC)-C-13)(2) is displaced by C-4(NC)(2), even after 120 h, demonstrating that only 34-39% of the diisocyanide m-xylyl((NC)-C-13)(2) is exchangeable and the remaining 61-66% of the diisocyanide is kinetically inert to exchange. The existence of two adsorption regimes, low coverage (less than 61-66%) and high coverage (greater than 61-66%), on the Au powder is supported by a variety of evidence. Reaction quotients (Q(ab)), which probably include both kinetic and thermodynamic factors, for the adsorption of diisocyanides on Au increase significantly as the -(CH2)(x)-link between the -NC groups becomes shorter. The C-2(NC)(2) ligand has the highest Q(ab) value. These studies also show that the relative binding affinities of the isocyanides increase as the number of -NC groups in the ligand increases (RNC < R(NC)(2) < R(NC)(3)). C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Angelici, RJ (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 27 TC 36 Z9 36 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 26 PY 1998 VL 14 IS 11 BP 3071 EP 3078 DI 10.1021/la980207u PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZQ642 UT WOS:000073888500022 ER PT J AU Nymeyer, H Garcia, AE Onuchic, JN AF Nymeyer, H Garcia, AE Onuchic, JN TI Folding funnels and frustration in off-lattice minimalist protein landscapes SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT Colloquium on Computational Biomolecular Science CY SEP 11-13, 1997 CL IRVINE, CALIFORNIA SP Natl Acad Sci ID MOLECULAR-DYNAMICS SIMULATIONS; COMPUTER-SIMULATION; ENERGY LANDSCAPES; BUNDLE PROTEIN; MODEL; KINETICS; HETEROPOLYMERS; PATHWAYS; MECHANISM; SEQUENCES AB A full quantitative understanding of the protein folding problem is now becoming possible with the help of the energy landscape theory and the protein folding funnel concept. Good folding sequences have a landscape that resembles a rough funnel where the energy bias towards the native state is larger than its ruggedness. Such a landscape leads not only to fast folding and stable native conformations but, more importantly, to sequences that are robust to variations in the protein environment and to sequence mutations. In this paper, an off-lattice model of sequences that fold into a beta-barrel native structure is used to describe a framework that can quantitatively distinguish good and bad folders. The two sequences analyzed have the same native structure, but one of them is minimally frustrated whereas the other one exhibits a high degree of frustration. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. RP Onuchic, JN (reprint author), Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. EM jonuchic@ucsd.edu FU NIGMS NIH HHS [T32 GM008326]; PHS HHS [T32 GN08326] NR 85 TC 269 Z9 272 U1 1 U2 22 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 26 PY 1998 VL 95 IS 11 BP 5921 EP 5928 DI 10.1073/pnas.95.11.5921 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ352 UT WOS:000073852600014 PM 9600893 ER PT J AU Rompel, A Cinco, RM Latimer, MJ McDermott, AE Guiles, RD Quintanilha, A Krauss, RM Sauer, K Yachandra, VK Klein, MP AF Rompel, A Cinco, RM Latimer, MJ McDermott, AE Guiles, RD Quintanilha, A Krauss, RM Sauer, K Yachandra, VK Klein, MP TI Sulfur K-edge x-ray absorption spectroscopy: A spectroscopic tool to examine the redox state of S-containing metabolites in vivo SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; TUNICATE ASCIDIA-CERATODES; GLASSY-CARBON ELECTRODE; ELECTROCHEMICAL DETECTION; GLUTATHIONE DISULFIDE; OXIDIZED GLUTATHIONE; REDUCED GLUTATHIONE; BIOLOGICAL SAMPLES; BLOOD-CELLS; CAPILLARY ELECTROPHORESIS AB The sulfur K-edge x-ray absorption spectra for the amino acids cysteine and methionine and their corresponding oxidized forms cystine and methionine sulfoxide are presented. Distinct differences in the shape of the edge and the inflection point energy for cysteine and cystine are observed. For methionine sulfoxide the inflection point energy is 2.8 eV higher compared with methionine. Glutathione, the most abundant thiol in animal cells, also has been investigated. The x-ray absorption near-edge structure spectrum of reduced glutathione resembles that of cysteine, whereas the spectrum of oxidized glutathione resembles that of cystine. The characteristic differences between the thiol and disulfide spectra enable one to determine the redox status (thiol to disulfide ratio) in intact biological systems, such as unbroken cells, where glutathione and cyst(e)ine are the two major sulfur-containing components. The sulfur K-edge spectra for whole human blood, plasma, and erythrocytes are shown. The erythrocyte sulfur K-edge spectrum is similar to that of fully reduced glutathione. Simulation of the plasma spectrum indicated 32% thiol and 68% disulfide sulfur. The whole blood spectrum can be simulated by a combination of 46% disulfide and 54% thiol sulfur. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Klein, MP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. EM VKYachandra@LBL.gov; MPKlein@LBL.Gov RI Quintanilha, Alexandre/L-5371-2013; OI Quintanilha, Alexandre/0000-0001-8544-0061; McDermott, Ann/0000-0002-9249-1649 NR 76 TC 74 Z9 75 U1 0 U2 12 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 26 PY 1998 VL 95 IS 11 BP 6122 EP 6127 DI 10.1073/pnas.95.11.6122 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ352 UT WOS:000073852600049 PM 9600928 ER PT J AU Sago, H Carlson, EJ Smith, DJ Kilbridge, J Rubin, EM Mobley, WC Epstein, CJ Huang, TT AF Sago, H Carlson, EJ Smith, DJ Kilbridge, J Rubin, EM Mobley, WC Epstein, CJ Huang, TT TI Ts1Cje, a partial trisomy 16 mouse model for Down syndrome, exhibits learning and behavioral abnormalities SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID AGE-RELATED NEURODEGENERATION; ALZHEIMERS-DISEASE; PROTEIN; GENE; LETHALITY; RATS AB A mouse model for Down syndrome, Ts1Cje, has been developed. This model has made possible a step in the genetic dissection of the learning, behavioral, and neurological abnormalities associated with segmental trisomy for the region of mouse chromosome 16 homologous with the so-called "Down syndrome region" of human chromosome segment 21q22. Tests of learning in the Morris water maze and assessment of spontaneous locomotor activity reveal distinct learning and behavioral abnormalities, some of which are indicative of hippocampal dysfunction. The triplicated region in Ts1Cje, from Sod1 to Mx1, is smaller than that in Ts65Dn, another segmental trisomy 16 mouse, and the learning deficits in Ts1Cje are less severe than those in Ts65Dn. In addition, degeneration of basal forebrain cholinergic neurons, which was observed in Ts65Dn, was absent in Ts1Cje. C1 Univ Calif San Francisco, Dept Pediat, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Neurol, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Human Genome, Berkeley, CA 94720 USA. RP Huang, TT (reprint author), Univ Calif San Francisco, Dept Pediat, Box 0546, San Francisco, CA 94143 USA. EM tthuang@itsa.ucsf.edu FU NHLBI NIH HHS [HL18574]; NIA NIH HHS [AG08938]; NICHD NIH HHS [HD31498] NR 32 TC 232 Z9 234 U1 0 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 26 PY 1998 VL 95 IS 11 BP 6256 EP 6261 DI 10.1073/pnas.95.11.6256 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ352 UT WOS:000073852600073 PM 9600952 ER PT J AU Xin, Y Pennycook, SJ Browning, ND Nellist, PD Sivananthan, S Omnes, F Beaumont, B Faurie, JP Gibart, P AF Xin, Y Pennycook, SJ Browning, ND Nellist, PD Sivananthan, S Omnes, F Beaumont, B Faurie, JP Gibart, P TI Direct observation of the core structures of threading dislocations in GaN SO APPLIED PHYSICS LETTERS LA English DT Article ID LIGHT-EMITTING-DIODES AB Here we present the first direct observation of the atomic structure of threading:: dislocation cores in hexagonal GaN. Using atomic-resolution Z-contrast imaging, dislocations with edge character are found to exhibit an eight-fold ring core. The central column in the core of a pure edge dislocation work, it is proposed that edge dislocations has the same configuration as one row of dimers on the {10-10} surface. Following recent theoretical work. It is proposed that edge dislocations do not have deep defect states in the band gap, and do not contribute to cathodoluminescence dislocation contrast. On the other hand, both mixed and pure screw dislocations are found to have a Cull core, and full screw dislocation cores were calculated to have states in the gap. (C) 1998 American Institute of Physics. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Cambridge, Cavendish Lab, Cambridge CB3 OHE, England. CNRS, CRHEA, F-06560 Valbonne, France. RP Xin, Y (reprint author), Univ Illinois, Dept Phys, Chicago, IL 60607 USA. OI Browning, Nigel/0000-0003-0491-251X NR 15 TC 144 Z9 147 U1 2 U2 40 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 25 PY 1998 VL 72 IS 21 BP 2680 EP 2682 DI 10.1063/1.121097 PG 3 WC Physics, Applied SC Physics GA 108NZ UT WOS:000075273500018 ER PT J AU Caturla, MJ Johnson, MD de la Rubia, TD AF Caturla, MJ Johnson, MD de la Rubia, TD TI The fraction of substitutional boron in silicon during ion implantation and thermal annealing SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSIENT ENHANCED DIFFUSION; B-DIFFUSION; SI; DEFECTS AB We present results from a kinetic Monte Carlo simulation of boron transient enhanced diffusion (TED) in silicon. Our approach avoids the use of phenomenological fits to experimental data by using a complete and self-consistent set of values for defect and dopant energetics derived mostly from ab initio calculations. The results predict that. during annealing of 40 keV B-implanted Si at 800 degrees C, there exists a time window during which all the implanted boron atoms are substitutional. Al earlier or later times, the interactions between free silicon self-interstitials and boron atoms drive the growth of boron clusters and result in an inactive boron fraction. The results show that the majority of boron TED takes place during the growth period of interstitial clusters and not during their dissolution. (C) 1998 American Institute of Physics. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Caturla, MJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Caturla, Maria /D-6241-2012 OI Caturla, Maria /0000-0002-4809-6553 NR 20 TC 67 Z9 67 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 25 PY 1998 VL 72 IS 21 BP 2736 EP 2738 DI 10.1063/1.121075 PG 3 WC Physics, Applied SC Physics GA 108NZ UT WOS:000075273500037 ER PT J AU Kershaw, DS Prasad, MK Shaw, MJ Milovich, JL AF Kershaw, DS Prasad, MK Shaw, MJ Milovich, JL TI 3D unstructured mesh ALE hydrodynamics with the upwind discontinuous finite element method SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID HYPERBOLIC CONSERVATION-LAWS; RAYLEIGH-TAYLOR INSTABILITY; DIFFERENCE-SCHEMES; SIMULATION; SYSTEMS AB We describe a numerical scheme to solve 3D Arbitrary Lagrangian-Eulerian (ALE) hydrodynamics on an unstructured mesh using discontinuous finite element space and an explicit Runge-Kutta time discretization. This scheme combines the accuracy of a higher-order Godunov scheme with the unstructured mesh capabilities of finite elements that can be explicitly evolved in time. The spatial discretization uses trilinear isoparametric elements (tetrahedrons, pyramids, prisms and hexahedrons) in which the primitive variables (mass density, velocity and pressure) are piecewise trilinear. Upwinding is achieved by using Roe's characteristic decomposition of the inter-element boundary flux depending on the sign of characteristic wave speeds. The characteristics are evaluated at the Roe average, of variables on both sides of the inter-element boundary, for a general equation of state. An explicit second order Runge-Kutta time stepping is used for the time discretization. To capture shocks, we have generalized van Leer's 1D nonlinear minmod slope limiter to 3D using a quadratic progamming scheme. For very strong shocks we find it necessary to supplement this with a Godunov stabilization where the trilinear representation of the variables is reduced to its constant average value. The resulting numerical scheme has been tested on a variety of problems relevant to ICF (inertial confinement fusion) target design and appears to be robust. It accurately captures shocks and contact discontinuities without unstable oscillations and has second-order accuracy in smooth regions. Object-oriented programming with the C++ programming language was used to implement our numerical scheme. The object-oriented design allows us to remove the complexities of an unstructured mesh from the basic physics modules and thereby enables efficient code development. (C) 1998 Elsevier Science S.A. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Prasad, MK (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 25 TC 29 Z9 29 U1 2 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD MAY 25 PY 1998 VL 158 IS 1-2 BP 81 EP 116 DI 10.1016/S0045-7825(97)00228-4 PG 36 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA ZV275 UT WOS:000074288300005 ER PT J AU Yoo, CS Soderlind, P Cynn, H AF Yoo, CS Soderlind, P Cynn, H TI The phase diagram of cobalt at high pressure and temperature: the stability of gamma(fcc)-cobalt and new epsilon '(dhcp)-cobalt SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID CRYSTAL-STRUCTURE; TRANSITION-METALS; EARTH-CORE; X-RAY; IRON AB A metastable dhcp phase of cobalt, epsilon'-Co, has been discovered below 60 GPa by using in situ x-ray diffraction and a laser-heated diamond-anvil cell. The volume at 34 GPa is 59.01 cm(3) mol(-1) with c/a = 3.190. First-principles theory shows that epsilon'(dhcp)-Co and epsilon(hcp)-Co are close in energy below 60 GPa, and that temperature and magnetic effects can make dhcp-Co more stable than hcp-Co. The gamma(fcc)-phase is found to be stable and quenchable over a wide range of pressure and temperature. New constraints for the phase diagram of Co are presented. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Yoo, CS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 20 TC 35 Z9 35 U1 4 U2 14 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 25 PY 1998 VL 10 IS 20 BP L311 EP L318 DI 10.1088/0953-8984/10/20/001 PG 8 WC Physics, Condensed Matter SC Physics GA ZT430 UT WOS:000074084900001 ER PT J AU Woychik, RP Klebig, ML Justice, MJ Magnuson, TR Avrer, ED AF Woychik, RP Klebig, ML Justice, MJ Magnuson, TR Avrer, ED TI Functional genomics in the post-genome era SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE functional genomics; gene expression; DNA chips; microhomologous recombination; ENU mutagenesis ID EMBRYONIC STEM-CELLS; POLYCYSTIC KIDNEY-DISEASE; SACCHAROMYCES-CEREVISIAE; TRANSGENIC MICE; HIGH-EFFICIENCY; MOUSE GENOME; GENE; MUTAGENESIS; STRATEGY; MUTATIONS AB As the biomedical research community enters the post-genome era, studying gene expression patterns and phenotypes in model organisms will be an important part of analyzing the role of genes in human health and disease. New technologies involving DNA chips will improve the ability to evaluate the differential expression of a large number of genes simultaneously. Also, new approaches for generating mutations in mice will significantly decrease the cost and increase the rate of generating mutant lines that model human disease. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Genet, Cleveland, OH 44106 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Woychik, RP (reprint author), Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, 11100 Euclid Ave, Cleveland, OH 44106 USA. NR 47 TC 32 Z9 49 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD MAY 25 PY 1998 VL 400 IS 1-2 SI SI BP 3 EP 14 DI 10.1016/S0027-5107(98)00023-2 PG 12 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 113JW UT WOS:000075548700002 PM 9685569 ER PT J AU Mohrenweiser, HW Jones, IM AF Mohrenweiser, HW Jones, IM TI Variation in DNA repair is a factor in cancer susceptibility: a paradigm for the promises and perils of individual and population risk estimation? SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE DNA repair; genetic variation; cancer susceptibility; risk estimation ID BREAST-CANCER; LUNG-CANCER; MUTANT FREQUENCY; MOLECULAR EPIDEMIOLOGY; GENETIC PREDISPOSITION; GENOMIC INSTABILITY; MUTAGEN SENSITIVITY; HUMAN-LYMPHOCYTES; POLYMERASE-BETA; EXCISION-REPAIR AB The repair of DNA damage protects the genome of the cell from the insults of cancer causing agents. This was originally demonstrated in individuals with the rare genetic disease, xeroderma pigmentosum, the prototype of cancer genes, and subsequently in the relationship of mismatch repair to colon cancer. Recent studies suggest that individuals with less dramatic reductions in the capacity to repair DNA damage are observed at polymorphic frequency and these individuals have an increased susceptibility to several types of cancer. Screening of individuals for DNA sequence variation in the exons of 9 DNA repair genes has resulted in identification of 15 different polymorphic amino acid substitution variants. Although the studies to relate these variants to reduced DNA repair capacity and cancer status have not been completed, the available information is sufficient to suggest that DNA repair genes should be incorporated into molecular epidemiology and cancer susceptibility studies. The availability of molecular epidemiology data presents exciting opportunities for refinement of risk estimation models and identification of individuals at increased risk of disease, with resultant opportunities for effective surveillance and early intervention and treatment. The opportunities to acquire susceptibility data are associated with possible perils for establishment of regulations for permissible exposures to carcinogenic agents and also stigmatization of 'at risk' individuals that may result in decreased access to employment opportunities and health care. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Mohrenweiser, HW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,7000 E Ave, Livermore, CA 94550 USA. EM mohrenweiserl@llnl.gov NR 72 TC 171 Z9 185 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD MAY 25 PY 1998 VL 400 IS 1-2 SI SI BP 15 EP 24 DI 10.1016/S0027-5107(98)00059-1 PG 10 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 113JW UT WOS:000075548700003 PM 9685572 ER PT J AU Russell, LB Hunsicker, PR Johnson, DK Shelby, MD AF Russell, LB Hunsicker, PR Johnson, DK Shelby, MD TI Unlike other chemicals, etoposide (a topoisomerase-II inhibitor) produces peak mutagenicity in primary spermatocytes of the mouse SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE topoisomerase-II; germ-cell-stage sensitivity; recombination; etoposide; specific-locus test; dominant mutation; germline mutagenesis; meiotic prophase; spermatocyte; deletion mutant ID MAMMALIAN-CELLS; RECOMBINATION; LOCUS; MICRONUCLEI; INDUCTION; EXPOSURE; MEIOSIS; MICE AB The cancer chemotherapy agent, and topoisomerase-LI inhibitor, etoposide (VP-16) produced both recessive mutations at specific loci and dominants at other loci with peak frequencies in primary spermatocytes, a cell type in which the topo-II gene has been shown to be activated. Etoposide thus differs from all other chemicals whose germ-cell-stage specificity has been analyzed. No effects of etoposide exposure of spermatogonial stem cells (similar to 15,000 offspring scored) were detectable by either mutagenicity or productivity endpoints. The significant mutagenic response that followed exposure of poststem-cell stages (similar to 25,000 offspring scored) showed a clear peak, with three of four specific-locus mutants, and three of four dominant mutants conceived during weeks 4 or 5 (days 22-35) post-injection, a period that also encompassed the dominant-lethal peak. For this period, the induced specific-locus rate (with 95% confidence limits) at a weighted-average exposure of 75.1 mg etop/kg was 59.5 (14.6, 170.9) x 10(-6)/locus. At least 3 of the 4 specific-locus mutations were deletions, paralleling findings with etoposide or analogs in other test systems where a recombinational origin of the deletions has been suggested. Because, unlike other chemicals that induce deletions in male germ cells, etoposide is effective in stages normally associated with recombinational events, it will be of interest to determine whether this chemical can affect meiotic recombination. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. NIEHS, Res Triangle Pk, NC 27709 USA. RP Russell, LB (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 2008, Oak Ridge, TN 37831 USA. FU NIEHS NIH HHS [1-Y01-ES-50318-00] NR 22 TC 27 Z9 28 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD MAY 25 PY 1998 VL 400 IS 1-2 SI SI BP 279 EP 286 DI 10.1016/S0027-5107(98)00036-0 PG 8 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 113JW UT WOS:000075548700026 PM 9685680 ER PT J AU Tucker, JD Sorensen, KJ Chu, CS Nelson, DO Ramsey, MJ Urlando, C Heddle, JA AF Tucker, JD Sorensen, KJ Chu, CS Nelson, DO Ramsey, MJ Urlando, C Heddle, JA TI The accumulation of chromosome aberrations and Dlb-1 mutations in mice with highly fractionated exposure to gamma radiation SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE low-dose fractionated exposure; gamma radiation; mouse; chromosome translocation; Dlb-1 gene mutation ID LOW-DOSE RADIATION; ADAPTIVE RESPONSE; IN-VIVO; IONIZING-RADIATION; PERIPHERAL-BLOOD; SOMATIC MUTATION; STEM-CELLS; MOUSE; INDUCTION; PERSISTENCE AB The dichotomy between the doses at which experimental measurements of genetic effects can be made and the doses to which people are exposed is often different by two or more orders of magnitude. This presents a significant problem when determining the effects of low doses of radiation or chemicals. The solution has usually involved extrapolating the data by curve-fitting or by applying theoretical considerations. Both approaches are unsatisfactory due to uncertainties of the assumptions used in each process. The alternative solution has been to increase the sample size enormously at the lower doses. This is impractical beyond a certain point due to the variation in the spontaneous frequency and the need to quadruple the sample size for a doubling of precision. The development of new methods for measuring stable genetic effects, however, permits a simple and effective approach to this problem: if the genetic events being detected have no effect on survival, i.e., are selectively neutral, then the effects of multiple independent treatments will be additive, if the independent treatments are identical, then the effect of each is easily calculated by dividing the total effect by the number of treatments. Here we report a limited test of this approach using mice. Chromosome aberrations induced in lymphocytes and Dlb-1 mutations induced in the small intestine were measured after daily doses of 0.64, 1.85 or 5.5 cGy Cs-137 gamma rays administered for 21, 42 or 63 days. The dose response curve for chromosome translocations obtained in this way, combined with the data from single larger acute doses, shows no evidence for a threshold over a 500-fold dose range. Dlb-1 mutations were increased at each dose and time but the results do not permit reliable extrapolations. The results suggest that translocations might be useful for quantifying the effect of doses below 0.05 cGy and that the effect of dose rate and dose fractionation at much lower doses than reported here could be investigated. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. York Univ, Dept Biol, N York, ON M3J 1P3, Canada. RP Tucker, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. NR 43 TC 30 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD MAY 25 PY 1998 VL 400 IS 1-2 SI SI BP 321 EP 335 DI 10.1016/S0027-5107(98)00048-7 PG 15 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 113JW UT WOS:000075548700030 PM 9685691 ER PT J AU Colvin, ME Hatch, FT Felton, JS AF Colvin, ME Hatch, FT Felton, JS TI Chemical and biological factors affecting mutagen potency SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE aromatic amine mutagen; food mutagen; review; quantitative structure-activity relationship; computational chemistry ID ARYL-O-PIVALOYLHYDROXYLAMINES; TRIPLET ARYLNITRENIUM ION; HUMAN HEPATIC MICROSOMES; UV-DAMAGED DNA; AROMATIC-AMINES; QUANTITATIVE STRUCTURE; NITRENIUM IONS; HETEROCYCLIC AMINES; ADDUCT FORMATION; CYTOCHROME-P-450 MONOOXYGENASES AB This review surveys the chemical and biological factors that are correlated with the mutagenic activity of the aromatic and heterocyclic amines, Particular attention is given to the predicted quantum chemical properties of the parent amines and their metabolites. A number of chemical properties have been found to correlate well with measured mutagenic potency, including log P, the energies of the frontier orbitals of the parent amines, and the thermodynamic stability of the nitrenium ion, possibly the ultimate DNA-binding species. These correlations are intriguing clues to the mutagenic activity of the aromatic amines; however, many factors still await final explanation, including the exact mechanisms of the metabolic enzymes, the identity(s) of the ultimate DNA-binding species, the reaction mechanism in the DNA-adduction, the role of sequence context in the covalent and non-covalent binding of the adducts, and the role of DNA repair. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Colvin, ME (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mailstop L-452, Livermore, CA 94550 USA. FU NCI NIH HHS [CA55861] NR 71 TC 32 Z9 32 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD MAY 25 PY 1998 VL 400 IS 1-2 SI SI BP 479 EP 492 DI 10.1016/S0027-5107(98)00073-6 PG 14 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 113JW UT WOS:000075548700043 PM 9685706 ER PT J AU Reid, RS Ward, WC Swift, GW AF Reid, RS Ward, WC Swift, GW TI Cyclic thermodynamics with open flow SO PHYSICAL REVIEW LETTERS LA English DT Article ID THERMOACOUSTIC ENGINES AB Some general features of a new class of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process are discussed and experimentally demonstrated in the context of a thermoacoustic refrigerator. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Reid, RS (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, POB 1663, Los Alamos, NM 87545 USA. NR 10 TC 21 Z9 21 U1 2 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4617 EP 4620 DI 10.1103/PhysRevLett.80.4617 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600002 ER PT J AU Bar-Shalom, S Eilam, G Soni, A AF Bar-Shalom, S Eilam, G Soni, A TI R-parity violation and CP-violating and CP-conserving spin asymmetries in l(+)l(-)->(nu)over-tilde ->tau(+)tau(-): Probing S neutrino mixing at l(+)l(-) colliders SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERSYMMETRY AB We consider the sneutrino resonance reaction l(+)l(-) --> (nu)over-tilde --> tau(+)tau(-) in the minimal supersymmetric standard model (MSSM) without R parity. We introduce CP-violating and CP-conserving tau-spin asymmetries which are generated at tree level if there is (nu)over-tilde-((nu)over-tilde)over-bar mixing and are forbidden in the standard model. At the CERN e(+)e(-) collider LEP2, these asymmetries may reach similar to 75% around resonance for sneutrino mass splitting of delta m similar to gamma((nu)over-barmu) and similar to 10% for splitting as low as delta m similar to 0.1 gamma((nu))over-bar-mu. They may be easily detectable if the beam energy is within similar to 10 GeV around the (nu)over-tilde(mu), mass and may therefore serve as powerful probes of sneutrino mixing. Future colliders are also discussed. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 19 TC 24 Z9 24 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4629 EP 4632 DI 10.1103/PhysRevLett.80.4629 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600005 ER PT J AU Diaz-Cruz, JL He, HJ Tait, T Yuan, CP AF Diaz-Cruz, JL He, HJ Tait, T Yuan, CP TI Higgs bosons with large bottom quark Yukawa coupling at the Fermilab Tevatron and CERN large hadron collider SO PHYSICAL REVIEW LETTERS LA English DT Article ID SYMMETRY-BREAKING; MODEL AB We study the discovery reach of the Fermilab Tevatron and the CERN large hadron collider (LHC) for detecting a Higgs boson (h), predicted in composite models of the electroweak symmetry breaking or in supersymmetric theories, with an enhanced b-quark Yukawa coupling via p (p) over bar/pp --> b (b) over bar h(--> b (b) over bar) + X. Our analysis shows that studying this process at the Tevatron Run II or the LHC can provide strong constraints on these models. C1 BUAP, Inst Fis, Puebla 72570, Mexico. Michigan State Univ, E Lansing, MI 48824 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Diaz-Cruz, JL (reprint author), BUAP, Inst Fis, Puebla 72570, Mexico. NR 26 TC 62 Z9 62 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4641 EP 4644 DI 10.1103/PhysRevLett.80.4641 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600008 ER PT J AU Wang, HY AF Wang, HY TI Short wave instability on vortex filaments SO PHYSICAL REVIEW LETTERS LA English DT Article ID EQUATIONS; EVOLUTION; FLOWS AB The short wave instability on corotating vortex filaments is investigated. It is shown that the short wave instability always occurs on corotating vortex filaments of fixed core structure. Moreover, when the interfilament distance is smaller than or comparable to the core size, vortex filaments produce short wave unstable modes which lead to wild stretching and folding; when vortex filaments are far apart from each other, unstable modes are bounded by a fraction of the core size and the vortex stretching remains bounded. These findings may be used to explain the smooth behavior of superfluid vortices. They also explain the stretching seen in numerical calculations. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. RP Wang, HY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,Mail Stop 50A-2152, Berkeley, CA 94720 USA. EM hwang@MATH.LBL.GOV NR 19 TC 5 Z9 5 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4665 EP 4668 DI 10.1103/PhysRevLett.80.4665 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600014 ER PT J AU Bai, M Ahrens, L Alessi, J Brown, K Bunce, G Cameron, P Chu, CM Glenn, JW Huang, H Kponou, AE Krueger, K Lamble, W Luccio, A Makdisi, YI Lee, SY Okamura, M Ratner, L Reece, K Roser, T Spinka, H Syphers, MJ Tsoupas, N Underwood, DG van Asselt, W Williams, N Yokosawa, A AF Bai, M Ahrens, L Alessi, J Brown, K Bunce, G Cameron, P Chu, CM Glenn, JW Huang, H Kponou, AE Krueger, K Lamble, W Luccio, A Makdisi, YI Lee, SY Okamura, M Ratner, L Reece, K Roser, T Spinka, H Syphers, MJ Tsoupas, N Underwood, DG van Asselt, W Williams, N Yokosawa, A TI Overcoming intrinsic spin resonances with an rf dipole SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARTIAL SIBERIAN SNAKE; BEAM; ACCELERATION; POLARIZATION AB A coherent spin resonance excited by an rf dipole was used to overcome depolarization due to intrinsic spin resonances at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory. We found that our data are consistent with a full spin flip of a polarized proton beam, without emittance growth, at G gamma = 12 + nu(z) and 36 - nu(z), by adiabatically exciting a vertical coherent betatron oscillation using a single rf dipole magnet. The interference pattern observed between the intrinsic spin resonance and the coherent spin resonance agrees well with multiparticle spin simulations based on a simple two-resonance model. The interference pattern can be used for beam diagnostics. C1 Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RIKEN, Inst Phys & Chem Res, Wako, Saitama 351, Japan. RP Bai, M (reprint author), Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. NR 14 TC 45 Z9 45 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4673 EP 4676 DI 10.1103/PhysRevLett.80.4673 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600016 ER PT J AU Floro, JA Lucadamo, GA Chason, E Freund, LB Sinclair, M Twesten, RD Hwang, RQ AF Floro, JA Lucadamo, GA Chason, E Freund, LB Sinclair, M Twesten, RD Hwang, RQ TI SiGe island shape transitions induced by elastic repulsion SO PHYSICAL REVIEW LETTERS LA English DT Article ID THIN-FILMS; GROWTH; GE; SI(001) AB The detailed morphological evolution during the transition between hut clusters and dome clusters is examined for Si0.8Ge0.2/Si(001) heteroepitaxy. Simultaneous real-time light scattering and stress measurements directly demonstrate the correlation between island impingement and the shape transformation. We show that elastic interactions between islands can significantly reduce the equilibrium transition volume and may also modify the activation barrier for the transition. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA. Brown Univ, Div Engn, Providence, RI 02912 USA. Univ Illinois, Ctr Microanal Mat, Urbana, IL 61801 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Floro, JA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 154 Z9 154 U1 0 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4717 EP 4720 DI 10.1103/PhysRevLett.80.4717 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600027 ER PT J AU Wang, LW Bellaiche, L Wei, SH Zunger, A AF Wang, LW Bellaiche, L Wei, SH Zunger, A TI "Majority representation" of alloy electronic states SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEMICONDUCTOR SOLID-SOLUTIONS; GAP; PHOTOLUMINESCENCE; SI1-XGEX AB Despite the lack of translational symmetry in random substitutional alloys, their description in terms of single Bloch states has been used in most phenomenological models and spectroscopic practices. We present a new way of analyzing the alloy electronic structures based on a "majority representation" phenomenon of the reciprocal space spectrum P(k) of the wave function. This analysis provides a quantitative answer to the questions: When can an alloy state be classified according to the crystal Bloch state symmetry, and under what circumstances are the conventional theoretical alloy models applicable. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wang, LW (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 23 TC 67 Z9 68 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4725 EP 4728 DI 10.1103/PhysRevLett.80.4725 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600029 ER PT J AU Muller, DA Shashkov, DA Benedek, R Yang, LH Silcox, J Seidman, DN AF Muller, DA Shashkov, DA Benedek, R Yang, LH Silcox, J Seidman, DN TI Atomic scale observations of metal-induced gap states at {222}MgO/Cu interfaces SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE; CERAMIC INTERFACES; RESOLUTION; MICROSCOPY; ADHESION; ENERGY; STEM AB {222} MgO/Cu interfaces produced by internal oxidation are studied by electron energy loss spectroscopy (EELS) using an atomic sized electron beam. We determine interfacial chemistry of this interface with subnanometer spatial resolution and use EELS to measure directly the electronic states pertaining to the buried interface. O, K, and Cu L-2,L-3 edges show the formation of metal-induced states within the band gap of MgO, at the interface (which we find to be O terminated). Both experiment and ab initio calculations find the metal-induced gap states to be strongly localized at the interface, resulting in a very small interface core-level shift. C1 Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Univ Calif Lawrence Livermore Natl Lab, Condensed Matter Phys Div, Livermore, CA 94551 USA. RP Muller, DA (reprint author), Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA. RI Seidman, David/B-6697-2009; Muller, David/A-7745-2010 OI Muller, David/0000-0003-4129-0473 NR 31 TC 94 Z9 94 U1 1 U2 23 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4741 EP 4744 DI 10.1103/PhysRevLett.80.4741 PG 4 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600033 ER PT J AU Marsili, M Maslov, S Zhang, YC AF Marsili, M Maslov, S Zhang, YC TI Comment on "Role of intermittency in urban development: A model of large-scale city formation" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Univ Fribourg Perolles, Inst Phys Theor, CH-1700 Fribourg, Switzerland. SISSA, Int Sch Adv Studies, I-34014 Trieste, Italy. INFM Unit, I-34014 Trieste, Italy. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Marsili, M (reprint author), Univ Fribourg Perolles, Inst Phys Theor, CH-1700 Fribourg, Switzerland. RI Maslov, Sergei/C-2397-2009 OI Maslov, Sergei/0000-0002-3701-492X NR 5 TC 7 Z9 7 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 25 PY 1998 VL 80 IS 21 BP 4830 EP 4830 DI 10.1103/PhysRevLett.80.4830 PG 1 WC Physics, Multidisciplinary SC Physics GA ZP849 UT WOS:000073794600056 ER PT J AU Tang, M Kubin, LP Canova, GR AF Tang, M Kubin, LP Canova, GR TI Dislocation mobility and the mechanical response of BCC single crystals: A mesoscopic approach SO ACTA MATERIALIA LA English DT Article ID PLASTIC-DEFORMATION; TRANSITION-METALS; LOW-TEMPERATURES; TANTALUM; NIOBIUM; ALLOYS; SLIP AB A mesoscopic simulation of dislocations and plasticity in b.c.c. crystals at low temperatures is developed and applied to the case of Ta. The thermally activated nucleation of double kinks is taken as controlling the mobility of screw dislocations. The resulting temperature and strain rate dependence of the yield stress are investigated and a detailed thermal activation analysis is performed on the output of the simulations. It is shown that within the simplifications made to the input parameters and slip geometry, one is able to simulate realistic dislocation structures and mechanical response. By checking the conformity between the input and output, it is shown that the essential dislocation property (activation energy for screw dislocation motion) can effectively be deduced from the mechanical rests. The mesoscopic simulation provides a potential tool to link atomistic studies at the microscopic scale to the macroscopic modeling of mechanical properties of b.c.c. metals at low temperatures. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Off Natl Etud & Rech Aerosp, CNRS, LEM, F-92322 Chatillon, France. ENSPG, GPM2, F-58402 St Martin Dheres, France. RP Tang, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-407, Livermore, CA 94550 USA. NR 53 TC 143 Z9 144 U1 3 U2 38 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 22 PY 1998 VL 46 IS 9 BP 3221 EP 3235 DI 10.1016/S1359-6454(98)00006-8 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZT576 UT WOS:000074101700025 ER PT J AU Hsueh, CH Becher, PF AF Hsueh, CH Becher, PF TI Interfacial smear debonding problems in fiber-reinforced ceramic composites SO ACTA MATERIALIA LA English DT Article ID PULL-OUT STRESSES; DISSIMILAR ELASTIC-MATERIALS; MATRIX COMPOSITES; CRACK DEFLECTION; STRENGTH; CRITERIA AB Toughening of fiber-reinforced ceramic composites by fiber pullout relies on mode II debonding at the fiber/matrix interface. This mode II debonding has been analyzed using the strength-based and the energy-based criteria, in which the interfacial shear strength and the interface debond energy are respectively adopted to characterize the debonding behavior. Using the concept of Griffith theory, an effective circumferential defect at the interface is defined to account for the stress intensity due to the presence of the fiber in the matrix and the fiber-pullout geometry. This effective circumferential defect is then used to derive the relation between the interfacial shear strength and the interface debond energy. Also, the condition of interfacial debonding vs fiber fracture for a bridging fiber behind the crack tip is established using the energy-based criterion. (C) 1998 Acta Metallurgica Inc. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 29 TC 14 Z9 15 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 22 PY 1998 VL 46 IS 9 BP 3237 EP 3245 DI 10.1016/S1359-6454(98)00008-1 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZT576 UT WOS:000074101700026 ER PT J AU Eng, J Raghavachari, K Struck, LM Chabal, YJ Bent, BE Banaszak-Holl, MM McFeely, FR Michaels, AM Flynn, GW Christman, SB Chaban, EE Williams, GP Radermacher, K Mantl, S AF Eng, J Raghavachari, K Struck, LM Chabal, YJ Bent, BE Banaszak-Holl, MM McFeely, FR Michaels, AM Flynn, GW Christman, SB Chaban, EE Williams, GP Radermacher, K Mantl, S TI An infrared study of H8Si8O12 cluster adsorption on Si(100) surfaces SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SIO2/SI INTERFACE; METAL LAYER; PHOTOEMISSION; SPECTROSCOPY; PRINCIPLES; SI(001) AB Motivated by a controversy about the proper interpretation of x-ray photoelectron spectra of Si/SiO2 interfaces derived from the adsorption of H8Si8O12 spherosiloxane clusters on Si(100) surfaces, we have studied the adsorption geometry of the H8Si8O12 clusters on deuterium-passivated and clean Si(100) surfaces by using external reflection infrared spectroscopy. Access to frequencies below 1450 cm(-1) was made possible through the use of specially prepared Si(100) samples which have a buried metallic CoSi2 layer that acts as an internal mirror. A comparison of the infrared spectrum of the clusters on a deuterium-passivated Si(100) surface at 130 K with an infrared spectrum of the clusters in a carbon tetrachloride solution reveals that the clusters are only weakly physisorbed on the D/Si(100) surface and also provides evidence for the purity of the cluster source. We also present infrared spectra of clusters directly chemisorbed on a clean Si(100) surface and show evidence that the clusters are adsorbed on the Si(100) via attachment by one vertex. A complete assignment of the observed vibrational features, for both physisorbed and chemisorbed clusters, has been made based upon comparisons with the results obtained in ab initio calculations using gradient-corrected density functional methods. (C) 1998 American Institute of Physics. [S0021-9606(98)02820-7]. C1 Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Columbia Univ, Dept Chem, New York, NY 10027 USA. Columbia Univ, Columbia Radiat Lab, New York, NY 10027 USA. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. IBM Corp, TJ Watson Res Labs, Yorktown Hts, NY 10598 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Forschungszentrum Julich, Inst Schicht & Ionentech, W-5170 Julich, Germany. RP Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. RI Chabal, Yves/A-5998-2011; Mantl, Siegfried/L-1317-2013 OI Chabal, Yves/0000-0002-6435-0347; Mantl, Siegfried/0000-0002-4266-0619 NR 21 TC 24 Z9 24 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1998 VL 108 IS 20 BP 8680 EP 8688 DI 10.1063/1.476411 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FQ UT WOS:000075255700043 ER PT J AU Szostek, B Aldstadt, JH AF Szostek, B Aldstadt, JH TI Determination of organoarsenicals in the environment by solid-phase microextraction gas chromatography mass spectrometry SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE soil; warfare agents; organoarsenic compounds; chlorovinylarsonous acid; arsenic ID MONOMETHYLARSONIC ACID; DERIVATIZATION; SAMPLES; SPECIATION; WATER AB The development of a method for the analysis of organoarsenic compounds that combines dithiol derivatization with solid-phase microextraction (SPME) sample preparation and gas chromatography-mass spectrometry (GC-MS) is described. Optimization focused on a SPME-GC-MS procedure for determination of 2-chlorovinylarsonous acid (CVAA), the primary decomposition product of the chemical warfare agent known as Lewisite. Two other organoarsenic compounds of environmental interest, dimethylarsinic acid and phenylarsonic acid, were also studied. A series of dithiol compounds was examined for derivatization of the arsenicals, and the best results were obtained either with 1,3-propanedithiol or 1,2-ethanedithiol. The derivatization procedure, fiber type, and extraction time were optimized. For CVAA, calibration curves were linear over three orders of magnitude and limits-of-detection were <6.10(-9) M in solution, the latter a more than 400x improvement compared to conventional solvent extraction GC-MS methods. A precision of <10% R.S.D. was typical for the SPME-GC-MS procedure. The method was applied to a series of water samples and soil/sediment extracts, as well as to aged soil samples that had been contaminated with Lewisite. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Aldstadt, JH (reprint author), Argonne Natl Lab, Div Environm Res, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 29 TC 73 Z9 80 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 22 PY 1998 VL 807 IS 2 BP 253 EP 263 DI 10.1016/S0021-9673(98)00080-6 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZT051 UT WOS:000074042800008 PM 9646499 ER PT J AU Bilyk, VA Shablov, VL Krstic, PS Schultz, DR AF Bilyk, VA Shablov, VL Krstic, PS Schultz, DR TI Coulomb effects in the interaction of a charged particle with a two-fragment quantum system SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article AB A direct method to derive the expression for the polarization potential between a charged particle and a two-fragment quantum system is developed. This method is based on the asymptotic properties of the two-body Coulomb Green function. The explicit form of the polarization potential constant is obtained for low-energy deuteron-nucleus scattering and for ion-hydrogen scattering. The properties of the polarization potential at high collision energies are applied to obtain an expression for the ion-atom scattering total cross section. C1 Obninsk Inst Nucl Power Engn, Obninsk, Russia. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA. RP Bilyk, VA (reprint author), Obninsk Inst Nucl Power Engn, Obninsk, Russia. NR 18 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD MAY 22 PY 1998 VL 31 IS 20 BP 4743 EP 4754 DI 10.1088/0305-4470/31/20/011 PG 12 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA ZT435 UT WOS:000074085400011 ER PT J AU Taylor, RE Kirner, DL Southon, JR Chatters, JC AF Taylor, RE Kirner, DL Southon, JR Chatters, JC TI Radiocarbon dates of Kennewick Man SO SCIENCE LA English DT Letter ID MARINE C1 Univ Calif Riverside, Inst Geophys & Planetary Phys, Dept Anthropol, Radiocarbon Lab, Riverside, CA 92521 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. Appl Paleosci, Richland, WA 99352 USA. RP Taylor, RE (reprint author), Univ Calif Riverside, Inst Geophys & Planetary Phys, Dept Anthropol, Radiocarbon Lab, Riverside, CA 92521 USA. NR 8 TC 15 Z9 15 U1 0 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 22 PY 1998 VL 280 IS 5367 BP 1171 EP + PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ351 UT WOS:000073852500002 PM 9634389 ER PT J AU Hill, SE Feller, D Glendening, ED AF Hill, SE Feller, D Glendening, ED TI Theoretical study of cation/ether complexes: Alkali metal cations with 1,2-dimethoxyethane and 12-crown-4 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID BOND-DISSOCIATION ENERGIES; AMMONIUM ION COMPLEXES; GAS-PHASE; CROWN-ETHERS; AB-INITIO; BASIS-SETS; EQUILIBRIUM STRUCTURES; MOLECULAR CALCULATIONS; WATER INTERACTIONS; FORCE-FIELD AB Hartree-Fock and second-order perturbation theory methods were used to determine structures and binding enthalpies of complexes formed from a single alkali metal cation (Li+ through Cs+) and one or two 1,2-dimethoxyethane ligands or 12-crown-4. These calculations employed multiple basis sets in order to determine the sensitivity of the results to the completeness in the one-particle basis. The results are compared with recently reported collision-induced dissociation experimental findings. In general, good agreement was found between the experimental and theoretical bond dissociation enthalpies, although for the heavier cations discrepancies of as much as 14 kcal/mol or more were uncovered. Possible reasons for these anomalies are discussed. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Feller, D (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, 906 Battelle Blvd,MS K1-96, Richland, WA 99352 USA. NR 54 TC 84 Z9 84 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 21 PY 1998 VL 102 IS 21 BP 3813 EP 3819 DI 10.1021/jp980522p PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZR649 UT WOS:000073999900023 ER PT J AU Skinner, DE Germann, TC Miller, WH AF Skinner, DE Germann, TC Miller, WH TI Quantum mechanical rate constants for O+OH reversible arrow H+O-2 for total angular momentum J > 0 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-STATE THEORY; UNIMOLECULAR DISSOCIATION HO2->H+O-2; DISCRETE VARIABLE REPRESENTATIONS; BOUND-STATES; REACTIVE SCATTERING; COMBUSTION REACTION; HO2; MOLECULES; PROBABILITIES; APPROXIMATION AB Thermal rate constants have been calculated for the titled reaction for total angular momentum J > 0 using the quantum flux correlation function methodology of Thompson and Miller [Thompson, W. H.; Miller, W. H. J. Chem. Phys. 1995, 102, 7409]. This generalizes earlier work by two of us [Germann,T. C.; Miller, W. H. J. Phys. Chem. A 1997, 101, 6358] for J = 0. A helicity conserving approximation (HCA) is used for the present J > 0 calculations, and it and other approximations for treating J > 0 are discussed and compared. The results show that for this reaction the much simpler J-shifting approximation (JSA) is reasonably accurate (to 10-20% in the rate constants), provided the appropriate choice is made for the reference geometry in this approach. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Miller, WH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 58 TC 32 Z9 32 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 21 PY 1998 VL 102 IS 21 BP 3828 EP 3834 DI 10.1021/jp980872b PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZR649 UT WOS:000073999900025 ER PT J AU Nishikawa, M Holroyd, R Itoh, K AF Nishikawa, M Holroyd, R Itoh, K TI Electron attachment to NO in supercritical ethane SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PARTIAL MOLAR VOLUMES; NONPOLAR-SOLVENTS; PRESSURE; FLUIDS; CO2; 2,2-DIMETHYLBUTANE; EQUILIBRIUM; TEMPERATURE; MOBILITY; METHANE AB Electron attachment to NO was studied in supercritical ethane at 33, 37, and 47 degrees C as a function of pressure (35-110 bar). The rate constant for electron attachment increases with increasing pressure at all temperatures studied. The most dramatic increases are observed near the critical pressure. The activation volume for this reaction is negative and quite large in magnitude, especially in this region. The activation volume depends on the isothermal compressibility. The results are compared to volume changes predicted by a compressible continuum model. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Kanagawa Inst Technol, Fac Engn, Atsugi, Kanagawa 24302, Japan. Univ Tokyo, Dept Pure & Appl Sci, Tokyo 153, Japan. RP Holroyd, R (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 24 TC 11 Z9 11 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 21 PY 1998 VL 102 IS 21 BP 4189 EP 4192 DI 10.1021/jp980285q PG 4 WC Chemistry, Physical SC Chemistry GA ZR647 UT WOS:000073999700024 ER PT J AU Van Patten, PG Shreve, AP Lindsey, JS Donohoe, RJ AF Van Patten, PG Shreve, AP Lindsey, JS Donohoe, RJ TI Energy-transfer modeling for the rational design of multiporphyrin light-harvesting arrays SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID COVALENTLY-LINKED PORPHYRIN; TETRAPHENYLPORPHYRIN MOLECULES; ELECTRONIC COMMUNICATION; OPTICAL-PROPERTIES; PHOTOSYNTHESIS; COMPLEXES; ZINC; FLUORESCENCE; ANTENNA; LUMINESCENCE AB Excited-state energy migration among a collection of pigments forms the basis for natural light-harvesting processes and synthetic molecular photonic devices. The rational design of efficient energy-transfer devices requires the ability to analyze the expected performance characteristics of target molecular architectures comprised of various pigments. Toward that goal, we present a general tool for modeling the kinetics of energy migration in weakly coupled multipigment arrays. A matrix-formulated eigenvalue/eigenvector approach has been implemented, using empirical data from a small set of prototypical molecules, to predict the quantum efficiency (QE) of energy migration in a variety of arrays as a function of rate, competitive processes, and architecture. Trends in the results point to useful design strategies including the following: (1) The QE for energy transfer to a terminal acceptor upon random excitation within a linear array of isoenergetic pigments decreases rapidly as the length of the array is increased. (2) Increasing the rate of transfer and/or the lifetime of the competitive deactivation processes significantly improves QE. (3) Qualitatively similar results are obtained in simulations of linear molecular photonic wires in which excitation and trapping occur at opposite ends of the array. (4) Branched and cyclic array architectures exhibit higher QEs than linear architectures with equal numbers of pigments. (5) Dramatic improvements in QE are achieved when energy transfer is directed by a progressive downward cascade in excited-state energy. (6) The most effective light-harvesting architectures are those where isolated pools of donors each have independent paths directly to the terminal acceptor. Collectively, these results provide valuable insight into the types of molecular designs that are expected to exhibit high efficiency in overall energy transfer. C1 Los Alamos Natl Lab, Biochem & Biotechnol Grp, Los Alamos, NM 87545 USA. N Carolina State Univ, Dept Chem, Raleigh, NC 27695 USA. RP Los Alamos Natl Lab, Biochem & Biotechnol Grp, CST-4,MS J586, Los Alamos, NM 87545 USA. RI Lindsey, Jonathan/J-7761-2012 NR 77 TC 125 Z9 125 U1 1 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 21 PY 1998 VL 102 IS 21 BP 4209 EP 4216 DI 10.1021/jp972304m PG 8 WC Chemistry, Physical SC Chemistry GA ZR647 UT WOS:000073999700027 ER PT J AU Starrfield, S Truran, JW Wiescher, MC Sparks, WM AF Starrfield, S Truran, JW Wiescher, MC Sparks, WM TI Evolutionary sequences for Nova V1974 Cygni using new nuclear reaction rates and opacities SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Review DE convection; nuclear reactions, nucleosynthesis, abundances; stars, activity; stars, individual, Nova V1974 Cygni; novae, cataclysmic variables; white dwarfs ID ULTRAVIOLET SPECTRAL EVOLUTION; THERMONUCLEAR REACTION-RATES; POSSESSING ANGULAR-MOMENTUM; HEAVY ELEMENT ABUNDANCES; WHITE-DWARF MASS; CLASSICAL NOVAE; PROTON CAPTURE; HERCULIS 1991; RP-PROCESS; AL-26 PRODUCTION AB The outburst of Nova V1974 Cyg 1992 is arguably the best observed of this century, with realistic estimates now available for the amount of mass ejected, the composition of the ejecta and the total energy budget. These data strongly support the conclusion that this was indeed a 'neon' nova that occurred on an oxygen, neon, magnesium white dwarf. In addition, X-ray studies of its outburst imply that the mass of the white dwarf is about 1.25 M.. We, therefore, report on the results of new calculations of thermonuclear runaways on 1.25-M. oxygen, neon, magnesium white dwarfs, using our one-dimensional, fully implicit, hydrodynamic stellar evolution code that includes a large nuclear reaction network. We have updated the nuclear reaction network, with the inclusion of new and improved experimental and theoretical determinations of the nuclear reaction rates. We have also incorporated the OPAL carbon rich tables and have investigated the effects of changes in convective efficiency on the evolution. Our results show that the changes in the reaction rates and opacities that we have introduced produce important changes with respect to our previous studies. For example, relevant to nucleosynthesis considerations, a smaller amount of Al-26 is produced, while the abundances of P-31 and S-32 increase by factors of more than two. This change is attributed to the increased proton-capture reaction rates for some of the intermediate mass nuclei near 26Al and beyond, such that nuclear fusion to higher mass nuclei is enhanced. The characteristics of our models are then compared to observations of the outburst of V1974 Cyg 1992 and we find that the predicted amount of mass ejected is at least a factor of 10 less than observed. The low values for the amount of ejected mass are a consequence of the fact that the OPAL opacities are larger than those we previously used, which results in less mass being accreted on to the white dwarf. This is a general problem with respect to the comparison of observations and theory for ONeMg novae and we suggest a possible resolution of this discrepancy. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Los Alamos Natl Lab, XNH, Los Alamos, NM 87544 USA. RP Arizona State Univ, Dept Phys & Astron, POB 871504, Tempe, AZ 85287 USA. EM sumner.starrfield@asu.edu; truran@nova.uchicago.edu; Michael.C.Wiescher1@nd.edu; wms@lanl.gov NR 125 TC 154 Z9 154 U1 0 U2 5 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 1998 VL 296 IS 3 BP 502 EP 522 DI 10.1046/j.1365-8711.1998.01312.x PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZR687 UT WOS:000074003700006 ER PT J AU Skinner, CJ Becker, RH White, RL Exter, KM Barlow, MJ Davis, RJ AF Skinner, CJ Becker, RH White, RL Exter, KM Barlow, MJ Davis, RJ TI A large radio nebula around P Cygni SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE circumstellar matter; stars, individual, P Cyg; stars, mass-loss; stars, variables, other; radio continuum, stars ID EARLY-TYPE STARS; MASS-LOSS; STELLAR WIND; B1 IA+; RADIATION; SPECTROSCOPY; EMISSION; SPECTRUM; CARINAE AB We present a large set of radio observations of the luminous blue variable P Cygni. These include two 6-cm images obtained with MERLIN which spatially resolve the 6-cm photosphere, monitoring observations obtained at Jodrell Bank every few days over a period of two months, and VLA observations obtained every month for seven years, This combination of data shows that the circumstellar environment of P Cyg is highly inhomogeneous, that there is a radio nebula extending to almost an arcminute from the star at 2 and 6 cm, and that the radio emission is variable on a time-scale no longer than one month, and probably as short as a few days. This short-time-scale variability is difficult to explain, We present a model for the radio emission with which we demonstrate that the star has probably been losing mass at a significant rate for at least a few thousand years, and that it has undergone at least two major outbursts of increased mass loss during the past two millenia. C1 UCL, Dept Phys & Astron, London WC1E 6BT, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Lawrence Livermore Natl Lab, Expt Astrophys Lab, Livermore, CA 94551 USA. Univ Calif Davis, Dept Phys, Livermore, CA 95616 USA. Univ St Andrews, Dept Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Nuffield Radio Astron Observ Labs, Macclesfield SK5 9DL, Cheshire, England. RP UCL, Dept Phys & Astron, Gower St, London WC1E 6BT, England. RI White, Richard/A-8143-2012; Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 40 TC 28 Z9 28 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 1998 VL 296 IS 3 BP 669 EP 688 DI 10.1046/j.1365-8711.1998.01388.x PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZR687 UT WOS:000074003700021 ER PT J AU Eskildsen, MR Harada, K Gammel, PL Abrahamsen, AB Andersen, NH Ernst, G Ramirez, AP Bishop, DJ Mortensen, K Naugle, DG Rathnayaka, KDD Canfield, PC AF Eskildsen, MR Harada, K Gammel, PL Abrahamsen, AB Andersen, NH Ernst, G Ramirez, AP Bishop, DJ Mortensen, K Naugle, DG Rathnayaka, KDD Canfield, PC TI Intertwined symmetry of the magnetic modulation and the flux-line lattice in the superconducting state of TmNi2B2C SO NATURE LA English DT Article ID SINGLE-CRYSTAL; ERNI2B2C AB Materials that can in principle exhibit both superconductivity and ferromagnetism are caught in a dilemma: both states represent long-range order, but are in general mutually exclusive. When the material favours a ground state with a large magnetic moment, as is the case for Er4Rh4B (ref. 1), superconductivity is destroyed. For superconductivity to persist, the magnetic structure would need to adopt an antiferromagnetic modulation of short enough wavelength to ensure a small net moment on the length scale of the superconducting coherence length. The intermetallic-borocarbide superconductors(2-4) RNi2B2C (where R is a rare-earth element) have shed new light on this balance between magnetism and superconductivity. The response of these materials in the superconducting state to a magnetic field is dominated by the formation of a flux-line lattice-a regular array of quantized magnetic vortices whose symmetry and degree of order are easily modified and thus can be expected to interact with an underlying magnetic modulation. In TmNi2B2C, superconductivity and antiferromagnetic modulated ordering coexist below 1.5 K (refs 5-7). Here we present the results of a small-angle neutron-scattering study of this compound which show that the structure of the magnetic modulation and the symmetry of the flux-line lattice are intimately coupled, resulting in a complex phase diagram. C1 Riso Natl Lab, DK-4000 Roskilde, Denmark. Hitachi Ltd, Adv Res Lab, Hatoyama, Saitama 35003, Japan. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Eskildsen, MR (reprint author), Riso Natl Lab, POB 49, DK-4000 Roskilde, Denmark. RI Mortensen, Kell/A-5066-2009; Eskildsen, Morten/E-7779-2011; Andersen, Niels/A-3872-2012; Canfield, Paul/H-2698-2014 OI Mortensen, Kell/0000-0002-8998-9390; NR 19 TC 63 Z9 63 U1 0 U2 12 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 21 PY 1998 VL 393 IS 6682 BP 242 EP 245 DI 10.1038/30447 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZP513 UT WOS:000073761000045 ER PT J AU Boucham, A Boutigny, D De Bonis, I Jeremie, A Karyotakis, Y Lafaye, R Goodenough, C Hearty, C Heise, J Kelsey, M McKenna, J Dorfan, D Fernandez, J Sadrozinski, H Schumm, B Spencer, N Harton, J Malchow, R Smy, M Warner, D Broomer, B Erdos, E Ford, WT Gritsan, A Johnson, DR Krieg, H Roy, J Park, H Rankin, P Smith, JG Gaddi, A Morganti, M Raffaelli, F Borsato, E Caracciolo, R Dal Corso, F Fanin, C Morandin, M Posocco, M Santi, S Stroili, R Torassa, E Voci, C Bronzini, F Buccheri, A Ferroni, F Lamanna, E Mazzoni, MA Morganti, S Piredda, G Santacesaria, R Dow, S Karcher, A Levi, M von der Lippe, H Momayezi, M Bard, R Dallapiccola, C Fong, D Jawahery, H Miller, W Cowan, RF Yamamoto, RK Britton, DI Fernholz, R Houde, M MacFarlane, DB Patel, PM Trischuk, J Beaulieu, M Martin, JP Taras, P Woch, A Zacek, V Lu, C McDonald, KT Smith, AJS Sands, WR Bajic, A Boyarski, A Boyce, R Coupal, D Coward, D Harris, J Hodgson, J McDougald, M Morii, M Nelson, D Palrang, M Sciolla, G Schaffner, S Snyder, A Wagner, S Henderson, R Khan, N Pitman, D Roney, JM AF Boucham, A Boutigny, D De Bonis, I Jeremie, A Karyotakis, Y Lafaye, R Goodenough, C Hearty, C Heise, J Kelsey, M McKenna, J Dorfan, D Fernandez, J Sadrozinski, H Schumm, B Spencer, N Harton, J Malchow, R Smy, M Warner, D Broomer, B Erdos, E Ford, WT Gritsan, A Johnson, DR Krieg, H Roy, J Park, H Rankin, P Smith, JG Gaddi, A Morganti, M Raffaelli, F Borsato, E Caracciolo, R Dal Corso, F Fanin, C Morandin, M Posocco, M Santi, S Stroili, R Torassa, E Voci, C Bronzini, F Buccheri, A Ferroni, F Lamanna, E Mazzoni, MA Morganti, S Piredda, G Santacesaria, R Dow, S Karcher, A Levi, M von der Lippe, H Momayezi, M Bard, R Dallapiccola, C Fong, D Jawahery, H Miller, W Cowan, RF Yamamoto, RK Britton, DI Fernholz, R Houde, M MacFarlane, DB Patel, PM Trischuk, J Beaulieu, M Martin, JP Taras, P Woch, A Zacek, V Lu, C McDonald, KT Smith, AJS Sands, WR Bajic, A Boyarski, A Boyce, R Coupal, D Coward, D Harris, J Hodgson, J McDougald, M Morii, M Nelson, D Palrang, M Sciolla, G Schaffner, S Snyder, A Wagner, S Henderson, R Khan, N Pitman, D Roney, JM TI The BaBar drift chamber project SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The BaBar Drift Chamber is now under construction. We review its design, the progress in the construction of the components, the plan for assembly and stringing and we present test results obtained with a prototype exposed at SLAC to cosmic rays. We also report on projected dE/dx performance from beam tests done with a chamber with a different cell design. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, I-00185 Rome, Italy. Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Univ Calif Santa Cruz, Inst Particle Phys, Santa Cruz, CA 95064 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Pisa, INFN, I-56010 Pisa, Italy. Scuola Normale Super Pisa, I-56010 Pisa, Italy. Ist Nazl Fis Nucl, I-35131 Padua, Italy. Univ Padova, I-35131 Padua, Italy. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. McGill Univ, Montreal, PQ H3A 2T8, Canada. Univ Montreal, Grp Phys Particules, Lab Rene JA Levesque, Montreal, PQ H3C 3J7, Canada. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. RP Ferroni, F (reprint author), Ist Nazl Fis Nucl, Piazzale A Moro 2, I-00185 Rome, Italy. RI Torassa, Ezio/I-1788-2012; Schaffner, Stephen/D-1189-2011; Lamanna, Ernesto/C-7658-2012; Morandin, Mauro/A-3308-2016; OI Lamanna, Ernesto/0000-0002-7844-8230; Morandin, Mauro/0000-0003-4708-4240; CARACCIOLO, Roberto/0000-0003-0728-1303; Torassa, Ezio/0000-0003-2321-0599 NR 4 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 46 EP 52 DI 10.1016/S0168-9002(97)01232-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100013 ER PT J AU Bagnasco, S Dughera, G Giraudo, G Govi, G Marchetto, F Menichetti, E Pastrone, N Rumerio, P Trapani, PP AF Bagnasco, S Dughera, G Giraudo, G Govi, G Marchetto, F Menichetti, E Pastrone, N Rumerio, P Trapani, PP TI A straw chambers' tracker for the high rate experiment 835 at the Fermilab accumulator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB Two layers of proportional drift tubes (aluminum mylar straws) are staggered in two cylindrical light chambers to measure charged particles' azimuthal angle. To stand the high rates (similar to 10 kHz/cm(2)) and minimize the pile-up of the high luminosity experiment 835 at FNAL, a fast ASIC Amplifier-Shaper-Discriminator (ASD-8B) was chosen. The front-end electronics, designed exclusively with SMD components, was mounted on the downstream end plug of each chamber to avoid oscillations and noise. Design, construction and operational performances of these detectors are presented. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Torino, Dipartimento Fis Sperimentale, I-10100 Torino, Italy. Ist Nazl Fis Nucl, I-10100 Torino, Italy. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Pastrone, N (reprint author), Ist Nazl Fis Nucl, Via P Giuria 1, I-10100 Torino, Italy. NR 3 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 75 EP 78 DI 10.1016/S0168-9002(97)01239-4 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100020 ER PT J AU Haber, C AF Haber, C TI The ATLAS Semiconductor Tracker SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa ID SILICON MICROSTRIP DETECTORS AB The technical design of the silicon tracking system for ATLAS is described. It contains 61 m(2) of strip detectors, must function after integrated doses in excess of 10(14) protons/cm(2), and maintain mechanical tolerances characteristic of silicon detector resolutions over scales in excess of 1 m. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Haber, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 161 EP 166 DI 10.1016/S0168-9002(97)01256-4 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100039 ER PT J AU Kapustinsky, JS Boissevain, J Bosze, E Clark, D Jaffe, D Kim, SY Marek, L Simon-Gillo, J Sullivan, J van Hecke, H Xu, G AF Kapustinsky, JS Boissevain, J Bosze, E Clark, D Jaffe, D Kim, SY Marek, L Simon-Gillo, J Sullivan, J van Hecke, H Xu, G TI A double-metal silicon pad design for the PHENIX multiplicity/vertex detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The two endcaps of the PHENIX multiplicity/vertex detector are comprised of 24 wedge-shaped silicon pad detectors. The performance of a double-metal pad detector designed for these endcaps is described. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Calif Riverside, Riverside, CA 92521 USA. RP Kapustinsky, JS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Mail Stop 846, Los Alamos, NM 87545 USA. NR 2 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 173 EP 175 DI 10.1016/S0168-9002(97)01257-6 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100041 ER PT J AU Biggeri, U Borchi, E Bruzzi, M Li, Z Verbitskaya, E AF Biggeri, U Borchi, E Bruzzi, M Li, Z Verbitskaya, E TI Study of electrical properties of high- and medium-resistivity silicon detectors irradiated with very high neutron fluence SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB Electrical properties of high (4-6 k Omega cm) and medium (1-1.5 k Omega cm) resistivity p(+)/n/n(+) silicon detectors irradiated with very high fluence neutrons, up to 4x10(15) neutrons/cm(2), have been studied. Some new results are presented and discussed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Florence, Dipartimento Energet, Firenze, Italy. Ist Nazl Fis Nucl, I-50125 Firenze, Italy. RAS, AF Ioffe Physicotech Inst, St Petersburg, Russia. RP Li, Z (reprint author), Brookhaven Natl Lab, Bldg 535 B,POB 5000, Upton, NY 11973 USA. RI Verbitskaya, Elena/D-1521-2014; Bruzzi, Mara/K-1326-2015 OI Bruzzi, Mara/0000-0001-7344-8365 NR 9 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 176 EP 179 DI 10.1016/S0168-9002(97)01258-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100042 ER PT J AU Li, Z Anderson, D Barnett, B Beuttenmuller, R Chen, W Chien, CY Eremin, V Frautschi, M Grim, G Hu, G Kwan, S Lander, D Mani, S Pandey, SU Wang, Q Willard, S Xie, X AF Li, Z Anderson, D Barnett, B Beuttenmuller, R Chen, W Chien, CY Eremin, V Frautschi, M Grim, G Hu, G Kwan, S Lander, D Mani, S Pandey, SU Wang, Q Willard, S Xie, X TI Simulation and design of various configurations of silicon detectors for high irradiation tolerance up to 6 x 10(14) n/cm(2) in LHC application SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB Various new configurations (n(+)/p/p(+), n(+)/n/p(+) and p(+)/n/n(+)) of silicon detector designs have been simulated using processing and device simulation tools, before and after irradiation to various fluences. The aim of material selection and detector design is to ensure adequate charge collection after being irradiated up to 10(15) n/cm(2) (or 6 x 10(14) pi/cm(2)) in LHC environment, which corresponds to a net increase (with long-term anneal) of space charge of 7 x 10(13) cm(-3). Starting materials selected for simulations include high resistivity p-type silicon, medium and low resistivity n-type silicon. Design of multi-guard-rings structure fur high-voltage operation is also considered. First, irradiation data of low resistivity silicon detector is presented. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Johns Hopkins Univ, Baltimore, MD USA. Univ Calif Davis, Davis, CA USA. Wayne State Univ, Detroit, MI USA. NW Nucl Res Inst, Xian, Peoples R China. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Li, Z (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 5 TC 22 Z9 22 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 180 EP 183 DI 10.1016/S0168-9002(98)00084-9 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100043 ER PT J AU Ratzmann, P Flaugher, B Howell, J Hrycyk, M AF Ratzmann, P Flaugher, B Howell, J Hrycyk, M TI Selected mechanical engineering topics of the SVX II detector at CDF SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The CDF collaboration is designing a second-generation silicon detector, SVX II, for Run II of the Fermilab Tevatron Collider. Portions of the SVX II have been constructed for the purpose of mechanical testing and design verification. The cooling performance of the ladders has been measured and compared to values expected from earlier design work, and there is an update on the expected effect of radiation damage. The bulkhead, a precision machined support structure made of beryllium, is discussed from both a design and fabrication perspective. Adhesives for ladder construction and bulkhead gluing are discussed. The focus of this presentation is on in-hand materials and measurements which have been completed in support of the mechanical design. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Ratzmann, P (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 216 EP 217 DI 10.1016/S0168-9002(97)01264-3 PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100050 ER PT J AU Albiol, F Ballester, F Barbier, G Bernabeu, J Bonino, R Ciocio, A Clark, AG Couyoumtzelis, C Dane, J Demierre, P DeWitt, J Dorfan, DE Dubbs, T Emes, J Fasching, D Fuster, J Garcia, C Gilchriese, MGD Godlewski, J Gonzalez, S Grewal, A Grillo, AA Haber, C Hackett, C Haesler, P Hill, JC Holland, S Iwasaki, H Iwata, Y Jared, R Kashigin, S Kipnis, I Koetz, U Kondo, T Kowalewski, R Kroeger, W Lankford, A Bahilo, JL Moorhead, G Morgan, D Munday, DJ Murray, W Nickerson, R Ohsugi, T O'Shea, V Perrin, E Pier, S Phillips, PW Pulliam, T Richardson, J Rowe, WA Saavedra, A Sadrozinski, HFW Salt, J Sanchez, J Schmid, B Seiden, A Sellin, PJ Shapiro, M Siegrist, J Spencer, E Spieler, H Stapnes, S Takashima, R Tamura, N Taylor, G Terada, S Unno, Y Vuaridel, B Walsh, SM Wastie, R Weber, M Webster, A Wichmann, R Wilder, M AF Albiol, F Ballester, F Barbier, G Bernabeu, J Bonino, R Ciocio, A Clark, AG Couyoumtzelis, C Dane, J Demierre, P DeWitt, J Dorfan, DE Dubbs, T Emes, J Fasching, D Fuster, J Garcia, C Gilchriese, MGD Godlewski, J Gonzalez, S Grewal, A Grillo, AA Haber, C Hackett, C Haesler, P Hill, JC Holland, S Iwasaki, H Iwata, Y Jared, R Kashigin, S Kipnis, I Koetz, U Kondo, T Kowalewski, R Kroeger, W Lankford, A Bahilo, JL Moorhead, G Morgan, D Munday, DJ Murray, W Nickerson, R Ohsugi, T O'Shea, V Perrin, E Pier, S Phillips, PW Pulliam, T Richardson, J Rowe, WA Saavedra, A Sadrozinski, HFW Salt, J Sanchez, J Schmid, B Seiden, A Sellin, PJ Shapiro, M Siegrist, J Spencer, E Spieler, H Stapnes, S Takashima, R Tamura, N Taylor, G Terada, S Unno, Y Vuaridel, B Walsh, SM Wastie, R Weber, M Webster, A Wichmann, R Wilder, M TI Beam test of the ATLAS silicon detector modules SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa ID MICROSTRIP DETECTORS; BINARY READOUT; ELECTRONICS AB Results are reported from a beam test of prototype silicon microstrip detectors and front-end electronics developed for use in the LHC detector ATLAS. The detector assemblies ("modules") were 12 cm long and were read out with binary electronics. Both irradiated and unirradiated modules were measured in a 1.56 T magnetic field for efficiency, noise occupancy, and position resolution as a function of bias voltage, binary hit threshold, and detector rotation angle with respect to the beam direction. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Santa Cruz, SCIPP, Santa Cruz, CA 95064 USA. Univ Valencia, CSIC, IFIC, Valencia, Spain. Univ Geneva, Geneva, Switzerland. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Irvine, Irvine, CA USA. Univ Calif Santa Cruz, SCIPP, Santa Cruz, CA 95064 USA. Univ Wisconsin, Madison, WI USA. INP, Krakow, Poland. Univ Oxford, Oxford, England. Univ Melbourne, Melbourne, Vic, Australia. Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. Hiroshima Univ, Hiroshima, Japan. CERN, Geneva, Switzerland. Rutherford Appleton Lab, Chilton, England. Univ Glasgow, Glasgow, Lanark, Scotland. Univ Liverpool, Liverpool L69 3BX, Merseyside, England. Univ Sydney, Sydney, NSW 2006, Australia. Univ Oslo, Oslo, Norway. Kyoto Univ, Kyoto 612, Japan. Okayama Univ, Okayama 700, Japan. Univ Sheffield, Sheffield, S Yorkshire, England. RP Sadrozinski, HFW (reprint author), Univ Calif Santa Cruz, SCIPP, Santa Cruz, CA 95064 USA. RI Moorhead, Gareth/B-6634-2009; Holland, Stephen/H-7890-2013; O'Shea, Val/G-1279-2010; Bernabeu, Jose/H-6708-2015; Lozano-Bahilo, Julio/F-4881-2016; OI Moorhead, Gareth/0000-0002-9299-9549; O'Shea, Val/0000-0001-7183-1205; Bernabeu, Jose/0000-0002-0296-9988; Lozano-Bahilo, Julio/0000-0003-0613-140X; Colomer, Kiko Albiol/0000-0002-3824-2246 NR 6 TC 4 Z9 4 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 236 EP 239 DI 10.1016/S0168-9002(97)01269-2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100055 ER PT J AU Sinev, NB Brau, JE Abe, K Arodzero, AA Baltay, C Breidenbach, M Burrows, PN Chou, AS Crawford, G Damerell, CJS Dervan, PJ Dong, DN Emmett, W English, RL Etzion, E Frey, R Foss, M Haller, G Hasuko, K Hertzbach, SS Hoeflich, J Huber, J Huffer, ME Jackson, DJ Jaros, JA Kelsey, J Lee, I Lia, V Lintern, AL Liu, MX Manly, SL Masuda, H McKemey, AK Moore, TB Nichols, A Nagamine, T Oishi, N Osborne, LS Russell, JJ Ross, D Serbo, VV Sinnott, J Skarpaas, K Smy, MB Snyder, JA Strauss, MG Dong, S Suekane, F Taylor, FE Trandafir, AI Usher, T Verdier, R Watts, SJ Weiss, ER Yashima, J Yuta, H Zapalac, G AF Sinev, NB Brau, JE Abe, K Arodzero, AA Baltay, C Breidenbach, M Burrows, PN Chou, AS Crawford, G Damerell, CJS Dervan, PJ Dong, DN Emmett, W English, RL Etzion, E Frey, R Foss, M Haller, G Hasuko, K Hertzbach, SS Hoeflich, J Huber, J Huffer, ME Jackson, DJ Jaros, JA Kelsey, J Lee, I Lia, V Lintern, AL Liu, MX Manly, SL Masuda, H McKemey, AK Moore, TB Nichols, A Nagamine, T Oishi, N Osborne, LS Russell, JJ Ross, D Serbo, VV Sinnott, J Skarpaas, K Smy, MB Snyder, JA Strauss, MG Dong, S Suekane, F Taylor, FE Trandafir, AI Usher, T Verdier, R Watts, SJ Weiss, ER Yashima, J Yuta, H Zapalac, G TI Initial impact parameter resolution of the new SLD vertex detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa DE particle detector; pixel detector; vertex detector AB During 1996 the SLD collaboration completed the construction of, and began the operation of, a new vertex detector (VXD3). This detector, based on 96 CCD's each of 13 cm(2) area, is an upgrade of the original vertex detector of SLD (VXD2), and is made possible by advances in the technology of CCD detectors. New front-end electronics and a new data acquisition system were developed for this upgrade. Its improved characteristics will enhance many SLD measurements, and open the possibility to observe B-s(o)-mixing. More than 50 000 Z events obtained with the new vertex detector have been analyzed. Results on the new detector performance (including resolution evaluation) from this first data are presented. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Oregon, Eugene, OR 97403 USA. Tohoku Univ, Sendai, Miyagi 98077, Japan. Yale Univ, New Haven, CT 06511 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. MIT, Cambridge, MA 02139 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Brunel Univ, Uxbridge U8 3PM, Middx, England. Univ Wisconsin, Madison, WI 53706 USA. Nagoya Univ, Nagoya, Aichi 464, Japan. Colorado State Univ, Ft Collins, CO 80523 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Washington, Seattle, WA 98195 USA. RP Sinev, NB (reprint author), Univ Oregon, Eugene, OR 97403 USA. RI Frey, Raymond/E-2830-2016; OI Frey, Raymond/0000-0003-0341-2636; Liu, Ming/0000-0002-5992-1221 NR 4 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 243 EP 246 DI 10.1016/S0168-9002(97)01271-0 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100057 ER PT J AU Atac, M Bedeschi, F Berchiesi, G Cocca, E Di Girolamo, B Incagli, M Leone, S Lucchesi, D Parashar, N Pieroni, D Wallace, NB AF Atac, M Bedeschi, F Berchiesi, G Cocca, E Di Girolamo, B Incagli, M Leone, S Lucchesi, D Parashar, N Pieroni, D Wallace, NB TI Research for a fiber detector for CDF run II SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB In the course of research and development of a fiber detector for CDF Run II we have made measurements of the light yield increase due to fiber mirroring, and both the noise and rate capability of visible light photon detectors (VLPCs). We found the reflection coefficient, R = 0.65 +/- 0.01 could be obtained using aluminum sputtering, We also found that both the noise level and the rate capability of the VLPCs were acceptable for use in CDF for collider Run II. (C) 1998 Elsevier Science B,V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Ist Nazl Fis Nucl, Sez Pisa, I-56100 Pisa, Italy. RP Atac, M (reprint author), Fermi Natl Accelerator Lab, POB 500, MS 222, Batavia, IL 60510 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 261 EP 263 DI 10.1016/S0168-9002(97)01276-X PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100062 ER PT J AU Weilhammer, P Adam, W Bauer, C Berdermann, E Bogani, F Borchi, E Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van der Eijk, R van Eijk, B Fallou, A Fish, D Fried, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Kass, R Knopfle, KT Krammer, M Manfredi, PF Meier, D LeNormand Pan, LS Pernegger, H Pernicka, M Plano, R Re, V Riester, JL Roe, S Roff Rudge, A Schieber, M Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Tapper, RJ Tesarek, R Thomson, GB Trawick, M Trischuk, W Turchetta, R AF Weilhammer, P Adam, W Bauer, C Berdermann, E Bogani, F Borchi, E Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van der Eijk, R van Eijk, B Fallou, A Fish, D Fried, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Kass, R Knopfle, KT Krammer, M Manfredi, PF Meier, D LeNormand Pan, LS Pernegger, H Pernicka, M Plano, R Re, V Riester, JL Roe, S Roff Rudge, A Schieber, M Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Tapper, RJ Tesarek, R Thomson, GB Trawick, M Trischuk, W Turchetta, R TI Recent results on CVD diamond radiation sensors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking devices, both strip detectors and pixel detectors, will be discussed. Results from beam tests using a diamond strip detector which was read out with fast, 25 ns shaping time, radiation-hard pipeline electronics will be presented. (C) 1998 Elsevier Science B.V. All rights reserved. C1 CERN, Div PPE, CH-1211 Geneva, Switzerland. Austrian Acad Sci, Inst Hochenergiephys, A-1050 Vienna, Austria. MPI Kernphys, D-69029 Heidelberg, Germany. GSI, Darmstadt, Germany. LENS, Florence, Italy. Univ Florence, Florence, Italy. Ctr Rech Nucl, LEPSI, F-67037 Strasbourg, France. Rutgers State Univ, Piscataway, NJ 08855 USA. CPPM, F-13288 Marseille, France. LEPES, Grenoble, France. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Ohio State Univ, Columbus, OH 43210 USA. Univ Bristol, Bristol BS8 1TL, Avon, England. Univ Calif Los Alamos Natl Lab, Div Res, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Pavia, Dipartimento Elettron, I-27100 Pavia, Italy. Sandia Natl Labs, Livermore, CA 94550 USA. Univ Toronto, Toronto, ON M5S 1A7, Canada. RP Weilhammer, P (reprint author), CERN, Div PPE, CH-1211 Geneva, Switzerland. RI Krammer, Manfred/A-6508-2010; Grigoriev, Eugene/K-6650-2013; Bruzzi, Mara/K-1326-2015; Gheeraert, Etienne/E-8071-2015; OI Krammer, Manfred/0000-0003-2257-7751; Grigoriev, Eugene/0000-0001-7235-9715; Bruzzi, Mara/0000-0001-7344-8365; Gheeraert, Etienne/0000-0002-9952-5805; Re, Valerio/0000-0003-0697-3420; Sciortino, Silvio/0000-0003-0570-7489 NR 6 TC 20 Z9 22 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 264 EP 270 DI 10.1016/S0168-9002(97)01277-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100063 ER PT J AU Baumbaugh, A AF Baumbaugh, A TI Production testing issues for ASICs for high energy physics SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB Many high-energy physics experiments require a large number of channels in a small volume. The use of custom or Application Specific Integrated Circuits (ASICs) in the front ends is very popular and in many cases an absolute necessity. The tools to design ASICs are readily available and wafers can be processed at moderate costs. However, very few, if any, vendors will provide tested die or chips at a reasonable cost in the low quantities (few thousand to few tens of thousands) that most experiments require. This talk will discuss the cost of testing vs. not testing of ASICs as well as ASIC testing strategies and solutions for relatively small quantities of ASICs. Specifics of the solution used by the KTeV experiment at Fermilab and the low-cost test system developed for this need will be discussed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Div Res, Batavia, IL 60510 USA. RP Baumbaugh, A (reprint author), Fermi Natl Accelerator Lab, Div Res, POB 500, Batavia, IL 60510 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 275 EP 277 DI 10.1016/S0168-9002(97)01279-5 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100065 ER PT J AU De Geronimo, G Musumarra, A Tudisco, S AF De Geronimo, G Musumarra, A Tudisco, S TI Front-end electronics for a large-area silicon detector telescope SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB A large-area monolithic silicon detector telescope for particle identification has recently been realized. Due to the high capacitance (40 nF) of the Delta E stage, commercially available charge preamplifiers cannot be used. We report on the design and characterization of a charge preamplifier suitably developed for the Delta E stage. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Politecn Milan, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Lab Nazl Sud, I-95129 Catania, Italy. CEA, DSM, DAPNIA, SPhN, Saclay, France. Univ Catania, I-95124 Catania, Italy. RP De Geronimo, G (reprint author), Brookhaven Natl Lab, Instrumentat Div, Bldg 535B, Upton, NY 11973 USA. OI Tudisco, Salvatore/0000-0002-9390-9912 NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 307 EP 309 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100073 ER PT J AU Dorfan, D Schumm, B Spencer, E Coupal, D Nelson, D AF Dorfan, D Schumm, B Spencer, E Coupal, D Nelson, D TI A bipolar front-end integrated circuit for the BaBar helium drift chamber SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB A Bipolar chip consisting of 4 channels, each with a digital, and an analog output has been developed for use with the BaBar drift chamber. The full design is described and results from the prototype are presented. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Dorfan, D (reprint author), Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 310 EP 314 DI 10.1016/S0168-9002(97)01288-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100074 ER PT J AU O'Connor, P Gramegna, G Rehak, P Corsi, F Marzocca, C AF O'Connor, P Gramegna, G Rehak, P Corsi, F Marzocca, C TI Ultra low noise CMOS preamplifier-shaper for X-ray spectroscopy SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa DE CMOS preamplifier-shaper; X-ray spectroscopy; adaptive pole-zero suppression; adaptive bias circuit; best reported noise performance in CMOS ID DRIFT DETECTORS; SILICON AB We report here an Ultra Low Noise CMOS charge-sensitive amplifier (CSA) and a CSA-Shaper for X-ray spectroscopy, suitable for a small anode capacitance, low leakage current solid state detector. The continuously sensitive CSA and CSA-Shaper use a MOS transistor MF to discharge the integration capacitance; a novel self-bias circuit biases MF in the G Ohm region (subthreshold region) while tracking process, temperature and supply voltage variations. A T-Network in the DC-feedback improves the CSA gain linearity (within 0.1% up to 1.8 fC input charge). The CSA-Shaper features a novel Adaptive Pole-Zero cancellation scheme: the Zero in the Shaper adapts itself statically and dynamically to cancel the CSA Pole. The noise performance of the CSA has been measured: with no detector connected and MF pinched, the room-temperature equivalent noise charge (ENC) is 9e rms at 12 mu s shaping time. When connected to a cooled detector (T = - 75 degrees C), with MF in pinch off, an ENC of 13e rms is achieved (FHWM = 111 eV) at 2.4 mu s shaping time. This is the best reported energy resolution ever obtained with a CMOS preamplifier. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Politecn Bari, Dipartimento Elettrotecn & Elettron, I-70100 Bari, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Gramegna, G (reprint author), Politecn Bari, Dipartimento Elettrotecn & Elettron, Via E Orabona 4, I-70100 Bari, Italy. EM giuse@deeetr02.poliba.it OI CORSI, Francesco/0000-0003-2425-2272; Marzocca, Cristoforo/0000-0002-2804-2275 NR 17 TC 23 Z9 23 U1 3 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 315 EP 321 DI 10.1016/S0168-9002(97)01289-8 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100075 ER PT J AU Re, V DeWitt, J Dow, S Frey, A Johnson, RP Kroeger, W Kipnis, I Leona, A Luo, L Mandelli, E Manfredi, PF Nyman, M Pedrali-Noy, M Poplevin, P Perazzo, A Roe, N Spencer, N AF Re, V DeWitt, J Dow, S Frey, A Johnson, RP Kroeger, W Kipnis, I Leona, A Luo, L Mandelli, E Manfredi, PF Nyman, M Pedrali-Noy, M Poplevin, P Perazzo, A Roe, N Spencer, N TI The rad-hard readout system of the BaBar silicon vertex tracker SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa DE electronics; readout; vertex; noise AB This paper discusses the behaviour of a prototype rad-hard version of the chip developed for the readout of the BaBar silicon vertex tracker. A previous version of the chip, implemented in the 0.8 mu m HP rad-soft version has been thoroughly tested in the recent times. It featured outstanding noise characteristics and showed that the specifications assumed as target for the tracker readout were met to a very good extent. The next step was the realization of a chip prototype in the rad-hard process that will be employed in the actual chip production. Such a prototype is structurally and functionally identical to its rad-soft predecessor. However, the process parameters being different, and not fully mastered at the time of design, some deviations in the behaviour were to be expected. The reasons for such deviations have been identified and some of them were removed by acting on the points that were left accessible on the chip. Other required small circuit modifications that will not affect the production schedule. The tests done so far on the rad-hard chip have shown that the noise behaviour is very close to that of the rad-soft version, that is fully adequate for the vertex detector readout. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Pavia, Dipartimento Elettron, I-27100 Pavia, Italy. Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. RP Univ Pavia, Dipartimento Elettron, Via Ferrata 1, I-27100 Pavia, Italy. EM valerio@mirage.unipv.it OI Re, Valerio/0000-0003-0697-3420 NR 5 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 354 EP 359 DI 10.1016/S0168-9002(97)01298-9 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100084 ER PT J AU Zimmerman, T Huffman, T Srage, J Stroehmer, R Yarema, R Garcia-Sciveras, M Luo, L Milgrome, O AF Zimmerman, T Huffman, T Srage, J Stroehmer, R Yarema, R Garcia-Sciveras, M Luo, L Milgrome, O TI SVX3: A deadtimeless readout chip for silicon strip detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB A new silicon strip readout chip called the SVX3 has been designed for the 720 000 channel CDF silicon upgrade at Fermilab. SVX3 incorporates an integrator, analog delay pipeline, ADC, and data sparsification for each of 128 identical channels. Many of the operating parameters are programmable via a serial bit stream, which allows the chip to be used under a variety of conditions. Distinct features of SVX3 include use of a backside substrate contact for optimal ground referencing, and the capability of simultaneous signal acquisition and digital readout, allowing deadtimeless operation in the Fermilab Tevatron. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Yarema, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM yarema@fnal.gov NR 5 TC 27 Z9 27 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 369 EP 374 DI 10.1016/S0168-9002(97)01301-6 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100087 ER PT J AU Castoldi, A Gatti, E Guazzoni, C Longoni, A Rehak, P Struder, L AF Castoldi, A Gatti, E Guazzoni, C Longoni, A Rehak, P Struder, L TI A new high resolution X-ray imaging detector with fast read-out SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa DE X-ray imaging; X-ray detectors; fast read-out AB A new silicon detector design suitable for X-ray imaging is presented. The new detector features energy and position resolution comparable with a fully depleted pn-charge coupled device and read-out times of few tens of microseconds. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Politecn Milan, Dipartimento Elettron & Informaz, I-20133 Milan, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. MPI Halbleiterlab, D-81245 Munchen, Germany. RP Castoldi, A (reprint author), Univ Milan, Dipartimento Fis, Via Celoria 16, I-20133 Milan, Italy. RI Guazzoni, Chiara/A-5070-2008 OI Guazzoni, Chiara/0000-0001-6399-8670 NR 3 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 379 EP 381 DI 10.1016/S0168-9002(98)00090-4 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100089 ER PT J AU Engelfried, J Kilmer, J Ramberg, E Stutte, L Kozhevnikov, A Kubarovsky, V Molchanov, V Filimonov, I Nemitkin, A Rud, V AF Engelfried, J Kilmer, J Ramberg, E Stutte, L Kozhevnikov, A Kubarovsky, V Molchanov, V Filimonov, I Nemitkin, A Rud, V TI The E781 (SELEX) RICH detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa ID CHERENKOV AB First results from a new RICH detector, operating in an experiment currently taking data - Fermilab E781 (SELEX), are presented. The detector utilizes a matrix of 2848 phototubes for the photocathode. In a 650 GeV/c pi(-) beam the number of photons detected is 14 per ring, giving a figure of merit N-0 of 106 cm(-1). The ring radius resolution obtained is 1.2%. Results showing the particle identification ability of the detector are discussed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Inst High Energy Phys, Serpukhov, Russia. Moscow State Univ, Moscow, Russia. RP Stutte, L (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 8 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 439 EP 442 DI 10.1016/S0168-9002(98)00121-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100104 ER PT J AU Hoffman, EJ Tornai, MP Levin, CS MacDonald, LR Holdsworth, CH AF Hoffman, EJ Tornai, MP Levin, CS MacDonald, LR Holdsworth, CH TI A dual detector beta-ray imaging probe with gamma-ray background suppression for use in intra-operative detection of radiolabeled tumors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The basic concepts for a dual detector beta(+) imaging probe incorporating a method of gamma-ray background suppression were evaluated. The test devices consisted of a 1.2 cm(2) beta(+) imaging CaF2(Eu) scintillator disk optically coupled to a 1.7 mm thick, area-matched transparent diffuser disk, which in turn was coupled to sets of 2 x 2 or 4 x 4 mm(2) by 10 mm long EGO, GSO or LSO scintillators, which acted as both gamma-detectors as well as light guides for the CaF2(Eu) scintillation light, which in turn are attached to a fiber optic bundle coupled to a multichannel photomultiplier. Pulse shape discrimination allowed identification of the detector of interaction and coincidence between the two detectors allowed selection of beta(+)-only events. This type imaging detector system was shown to be capable of producing high-resolution images of beta(+) distributions while suppressing the events due to the 511 keV annihilation radiation background. GSO was found to be the detector of choice for this application. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Angeles, Sch Med, Div Nucl Med & Biophys, DoE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Hoffman, EJ (reprint author), Univ Calif Los Angeles, Sch Med, Div Nucl Med & Biophys, DoE Lab Struct Biol & Mol Med, B2-086CHS,10833 Le Conte Ave, Los Angeles, CA 90095 USA. NR 9 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 511 EP 516 DI 10.1016/S0168-9002(97)01305-3 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100122 ER PT J AU Majewski, S Farzanpay, F Goode, A Kross, B Steinbach, D Weisenberger, A Williams, M Wojcik, R AF Majewski, S Farzanpay, F Goode, A Kross, B Steinbach, D Weisenberger, A Williams, M Wojcik, R TI Development of an application specific scintimammography detector based on a crystal scintillator array and a PSPMT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB We report the results of studies conducted with small field of view scintimammography camera based on a position-sensitive photomultiplier tube (5 " Hamamatsu R3292) and several pixelized crystal scintillator arrays made of YAP, CsI(Na) and NaI(Tl) scintillators. Laboratory tests and pre-clinical phantom studies were conducted to compare and optimize the performances of the prototypes with special emphasis on spatial resolution (similar to 2-3 mm) and sufficient energy resolution for scatter rejection. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Thomas Jefferson Natl Accelerator Facil, Detector Grp, Newport News, VA 23606 USA. Univ Virginia, Charlottesville, VA 22903 USA. RP Majewski, S (reprint author), Thomas Jefferson Natl Accelerator Facil, Detector Grp, Newport News, VA 23606 USA. NR 3 TC 29 Z9 30 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 520 EP 523 DI 10.1016/S0168-9002(97)01307-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100124 ER PT J AU Anulli, F Asmone, A Ferroli, RB van Bibber, K Bionta, RM Buzzo, A Calcaterra, A Carlino, GP Cavallo, N Contri, R Crosetti, G de Sangro, R Fabozzi, F Falciai, D Franchi, TV Johnson, JR Lista, L Lo Vetere, M Macri, M Mele, S Monge, R Palano, A Pallavicini, M Paolucci, P Parascandolo, P Patrignani, C Peruzzi, I Pia, MG Piccolo, D Piccolo, M Robutti, E Santroni, A Sciacca, C Wenaus, TJ Wright, DM Yu, Z Zallo, A AF Anulli, F Asmone, A Ferroli, RB van Bibber, K Bionta, RM Buzzo, A Calcaterra, A Carlino, GP Cavallo, N Contri, R Crosetti, G de Sangro, R Fabozzi, F Falciai, D Franchi, TV Johnson, JR Lista, L Lo Vetere, M Macri, M Mele, S Monge, R Palano, A Pallavicini, M Paolucci, P Parascandolo, P Patrignani, C Peruzzi, I Pia, MG Piccolo, D Piccolo, M Robutti, E Santroni, A Sciacca, C Wenaus, TJ Wright, DM Yu, Z Zallo, A TI The muon and neutral hadron detector for BaBar SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The muon and neutral hadron detector of the BaBar experiment for the PEP-II Asymmetric B-factory at SLAG uses Resistive Plate Counters (RPCs) as active detectors. A large fraction of the total system, which consists of approximately 800 chambers for an overall surface of 2000 m(2), has already been built and tested in cosmic rays. Preliminary results of the operating characteristics with a new non-flammable and environmentally safe gas mixture are reported. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, I-70126 Bari, Italy. Univ Bari, I-70121 Bari, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, RM, Italy. Univ Genoa, Genova, Italy. Ist Nazl Fis Nucl, I-16146 Genova, Italy. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Univ Naples, I-80138 Naples, Italy. Ist Nazl Fis Nucl, I-80125 Napoli, Italy. Univ Perugia, Dipartimento Fis, I-06100 Perugia, Italy. Univ Wisconsin, Madison, WI 53706 USA. RP Anulli, F (reprint author), Ist Nazl Fis Nucl, Lab Nazl Frascati, POB 13, I-00044 Frascati, RM, Italy. EM fabio.anulli@lnf.infn.it RI Lista, Luca/C-5719-2008; Pia, Maria Grazia/C-7034-2012; de Sangro, Riccardo/J-2901-2012; Cavallo, Nicola/F-8913-2012; Monge, Maria Roberta/G-9127-2012; Lo Vetere, Maurizio/J-5049-2012; Pallavicini, Marco/G-5500-2012; Calcaterra, Alessandro/P-5260-2015; Patrignani, Claudia/C-5223-2009; OI Pia, Maria Grazia/0000-0002-3579-9639; de Sangro, Riccardo/0000-0002-3808-5455; Monge, Maria Roberta/0000-0003-1633-3195; Lo Vetere, Maurizio/0000-0002-6520-4480; Pallavicini, Marco/0000-0001-7309-3023; Calcaterra, Alessandro/0000-0003-2670-4826; Patrignani, Claudia/0000-0002-5882-1747; Sciacca, Crisostomo/0000-0002-8412-4072 NR 4 TC 7 Z9 7 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 542 EP 546 DI 10.1016/S0168-9002(97)01312-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100129 ER PT J AU Boca, G Gourlay, S Chung, YS Lee, KB Malvezzi, S Sal, A Arena, V Bonomi, G Gianini, G Merlo, M Ratti, S Riccardi, C Viola, L Vitulo, P AF Boca, G Gourlay, S Chung, YS Lee, KB Malvezzi, S Sal, A Arena, V Bonomi, G Gianini, G Merlo, M Ratti, S Riccardi, C Viola, L Vitulo, P TI A hadronic tile calorimeter report SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The design and first performances of a new hadronic calorimeter for the experiment Focus (E831) at Fermilab are presented. It is a sampling calorimeter, with 28 iron (passive) and scintillator (active) planes. The active planes are composed of tiles read out by Wavelength Shifter fibers spliced to clear fibers. This is the first the calorimeter actually used (1997) in a running experiment. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Pavia, Dipartimento Fis Nucl & Teor, I-27100 Pavia, Italy. Ist Nazl Fis Nucl, I-27100 Pavia, Italy. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Korea Univ, Seoul 136701, South Korea. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Ist Nazl Fis Nucl, I-20133 Milan, Italy. Univ Pavia, Dipartimento Fis Nucl & Teor, I-27100 Pavia, Italy. Ist Nazl Fis Nucl, I-27100 Pavia, Italy. RP Boca, G (reprint author), Univ Pavia, Dipartimento Fis Nucl & Teor, Via Bassi 6, I-27100 Pavia, Italy. RI Gianini, Gabriele/M-5195-2014 OI Gianini, Gabriele/0000-0001-5186-0199 NR 2 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 561 EP 563 DI 10.1016/S0168-9002(97)01318-1 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100133 ER PT J AU Akchurin, N Ayan, S Bencze, GL Chikin, K Cohn, H Doulas, S Dumanoglu, I Eskut, E Fenyvesi, A Ferrando, A Fouz, MC Gavrilov, V Gershtein, Y Hajdu, C Iosifidis, J Josa, MI Khan, A Kim, SB Kolosov, V Kuleshov, S Langland, J Litvinsev, D Merlo, JP Molnar, J Nikitin, A Onel, Y Onengut, G Osborne, D Ozdes-Kosa, N Penzo, A Pesen, E Podrasky, V Rosowsky, A Salicio, JM Stolin, V Sulak, L Sullivan, J Ulyanov, A Umashev, A Uzunian, S Vesztergombi, G Winn, D Winsor, R Zalan, P Zeyrek, M AF Akchurin, N Ayan, S Bencze, GL Chikin, K Cohn, H Doulas, S Dumanoglu, I Eskut, E Fenyvesi, A Ferrando, A Fouz, MC Gavrilov, V Gershtein, Y Hajdu, C Iosifidis, J Josa, MI Khan, A Kim, SB Kolosov, V Kuleshov, S Langland, J Litvinsev, D Merlo, JP Molnar, J Nikitin, A Onel, Y Onengut, G Osborne, D Ozdes-Kosa, N Penzo, A Pesen, E Podrasky, V Rosowsky, A Salicio, JM Stolin, V Sulak, L Sullivan, J Ulyanov, A Umashev, A Uzunian, S Vesztergombi, G Winn, D Winsor, R Zalan, P Zeyrek, M TI Test beam results of CMS quartz fibre calorimeter prototype and simulation of response to high energy hadron jets SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB CMS very forward calorimeter is based on a quartz fibre technology. The calorimeter prototype composed of two longitudinal segments was tested at CERN in 1996, We present the test beam data analysis of this prototype. It was shown that the mean values of responses for pions and electrons of the same energy could be equalised using the appropriate ratio of calibration constants for longitudinal segments. The beam test data were used to simulate the calorimeter response to hadron jets. (C) 1998 Elsevier Science B.V. All rights reserved. C1 ITEP, Moscow, Russia. Univ Iowa, Iowa City, IA 52242 USA. Middle E Tech Univ, TR-06531 Ankara, Turkey. KFKI RMKI, Budapest, Hungary. NPI Moscow State Univ, Moscow, Russia. Oak Ridge Natl Lab, Oak Ridge, TN USA. Boston Univ, Boston, MA 02215 USA. Cucurova Univ, Adana, Turkey. ATOMKI, Debrecen, Hungary. CIEMAT, E-28040 Madrid, Spain. Fairfield Univ, Fairfield, CT 06430 USA. Univ Trieste, I-34127 Trieste, Italy. Ist Nazl Fis Nucl, Trieste, Italy. RP Kolosov, V (reprint author), ITEP, Moscow, Russia. RI Kuleshov, Sergey/D-9940-2013; Kim, Soo-Bong/B-7061-2014; Josa, Isabel/K-5184-2014; Pesen, Erhan/B-1753-2017; OI Kuleshov, Sergey/0000-0002-3065-326X; Uliyanov, Alexey/0000-0001-6935-8949; Gershtein, Yuri/0000-0002-4871-5449 NR 7 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 593 EP 597 DI 10.1016/S0168-9002(97)01328-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100141 ER PT J AU Stahl, A AF Stahl, A TI The BaBar electromagnetic calorimeter SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The progress on the design and construction of the BABAR electromagnetic calorimeter including its mechanical structure, the readout system, the mechanical and optical properties of the crystals, and the schedule for the final assembly and testing is summarized. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Stahl, A (reprint author), Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. RI Stahl, Achim/E-8846-2011 OI Stahl, Achim/0000-0002-8369-7506 NR 0 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 615 EP 617 DI 10.1016/S0168-9002(97)01335-1 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100148 ER PT J AU White, SN AF White, SN TI Forward measurements in RHIC and LHC heavy ion collisions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB Two mechanisms for forward, correlated neutron emission in heavy ion collisions motivate the construction of compact hadron calorimeters to be placed downstream of interaction regions at RHIC and LHC. Plans are now underway to build such detectors. Here we discuss recent progress in understanding their role and performance requirements. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP White, SN (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. EM swhite@bnlarm.bnl.gov NR 5 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 618 EP 620 DI 10.1016/S0168-9002(97)01336-3 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100149 ER PT J AU Whitmore, J AF Whitmore, J TI The performance of a high speed pipelined photomultiplier readout system in the Fermilab KTeV experiment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 7th Pisa Meeting on Advanced Detectors CY MAY 25-31, 1997 CL LA BIODOLA, ITALY SP Ist Nazl Fis Nucl, Soc Italiana Fis, European Phys Soc, Univ Pisa AB The KTeV fixed target experiment at Fermilab is using an innovative scheme for reading out its 3100 channel CsI electromagnetic calorimeter. This pipelined readout system digitizes photomultiplier tube (PMT) signals over a 16-bit dynamic range with 8-bits of resolution at 53 MHz. The crucial element of the system is a custom Bi-CMOS integrated circuit which, in conjunction with an 8-bit Flash ADC, integrates and digitizes the PMT signal charge over each 18.9 ns clock cycle (53 MHz) in a deadtimeless fashion. The digitizer circuit is local to the PMT base, and has an in-situ charge integration noise figure of 3 fC/sample. In this article, the readout system will be described and its performance including noise, cross-talk, linearity, stability, and reliability will be discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Whitmore, J (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 2 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1998 VL 409 IS 1-3 BP 687 EP 690 DI 10.1016/S0168-9002(97)01352-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 103TZ UT WOS:000074975100166 ER PT J AU Farhi, E Graham, N Haagensen, P Jaffe, RL AF Farhi, E Graham, N Haagensen, P Jaffe, RL TI Finite quantum fluctuations about static field configurations SO PHYSICS LETTERS B LA English DT Article ID EXTENDED-HADRON MODELS; NONPERTURBATIVE METHODS; CHIRAL-SOLITON; VACUUM ENERGY; BAGS; SYMMETRY AB We develop an unambiguous and practical method to calculate one-loop quantum corrections to the energies of classical time-independent field configurations in renormalizable field theories. We show that the standard perturbative renormalization procedure suffices here as well. We apply our method to a simplified model where a charged scalar couples to a neutral "Higgs" field, and compare our results to the derivative expansion. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Brookhaven Natl Lab, RIKEN, BNL, Res Ctr, Upton, NY 11973 USA. RP Farhi, E (reprint author), MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. NR 24 TC 43 Z9 43 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 21 PY 1998 VL 427 IS 3-4 BP 334 EP 342 DI 10.1016/S0370-2693(98)00354-2 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZX699 UT WOS:000074545100018 ER PT J AU Burakovsky, L Goldman, T AF Burakovsky, L Goldman, T TI New mass and mass-mixing angle relations for pseudoscalar mesons SO PHYSICS LETTERS B LA English DT Article DE Schwinger's formula; Gell-Mann-Okubo; chiral Lagrangian; pseudoscalar mesons ID QUANTUM CHROMODYNAMICS; CHIRAL DYNAMICS; MODEL; ETA'; QUARK AB We study the origins of the inaccuracies of Schwinger's nonet mass, and the Sakurai mass-mixing angle, formulae for the pseudoscalar meson nonet, and suggest new versions of them, modified by the inclusion of the pseudoscalar decay constants. We use these new formulae to determine the pseudoscalar decay constants and mixing angle. The results obtained, f(8)/f(pi) = 1.185 +/- 0.040, f(q)/f(pi) = 1.095 +/- 0.020, f(eta)/f(pi) = 1.085 +/- 0.025, f(eta)/f(pi) = 1.195 +/- 0.035, theta = (- 21.4 +/- 1.0)degrees, are in excellent agreement with experiment. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Burakovsky, L (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B285, Los Alamos, NM 87545 USA. EM BURAKOV@T5.LANL.GOV; GOLDMAN@T5.LANL.GOV NR 36 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 21 PY 1998 VL 427 IS 3-4 BP 361 EP 370 DI 10.1016/S0370-2693(98)00365-7 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZX699 UT WOS:000074545100023 ER PT J AU Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alverson, G Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A BIlei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Boucham, A Bourilkov, D Bourquin, M Boutigny, D Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chen, M Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Commichau, V Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dorne, I Dova, MT Gerald, J Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A van Hoek, WC Hofer, H Hong, SJ Hoorani, H Hou, SR Hu, G Innocente, V Janssen, H Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kim, YG Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A de Guevara, PL Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Leggett, C Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Mihul, A van Mil, AJW Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Morganti, S Moulik, T Mount, R Muller, S Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Pinto, JC Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Rind, O Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Sassowsky, M Sauvage, G Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Schmitz, P Schneegans, M Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Sopczak, A Soulimov, V Smith, B Spillantini, P Steuer, M Stickland, DP Stone, H Stoyanov, B Straessner, A Strauch, K Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonutti, M Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Van de Walle, RT Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wittgenstein, F Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP Zhou, B Zhou, Y Zhu, GY Zhu, RY Zichichi, A Ziegler, F Drago, E Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garica-Abia, P Gau, SS Gentile, S AF Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alverson, G Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A BIlei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Boucham, A Bourilkov, D Bourquin, M Boutigny, D Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chen, M Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Commichau, V Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dorne, I Dova, MT Gerald, J Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A van Hoek, WC Hofer, H Hong, SJ Hoorani, H Hou, SR Hu, G Innocente, V Janssen, H Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kim, YG Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A de Guevara, PL Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Leggett, C Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Mihul, A van Mil, AJW Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Morganti, S Moulik, T Mount, R Muller, S Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Pinto, JC Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Rind, O Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Sassowsky, M Sauvage, G Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Schmitz, P Schneegans, M Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Sopczak, A Soulimov, V Smith, B Spillantini, P Steuer, M Stickland, DP Stone, H Stoyanov, B Straessner, A Strauch, K Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonutti, M Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Van de Walle, RT Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wittgenstein, F Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP Zhou, B Zhou, Y Zhu, GY Zhu, RY Zichichi, A Ziegler, F Drago, E Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garica-Abia, P Gau, SS Gentile, S CA L3 Collaboration TI K-s(0) and Lambda production in quark and gluon jets at LEP (vol 407, pg 407, 1997) SO PHYSICS LETTERS B LA English DT Correction C1 Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. CNRS, IN2P3, LAPP, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. IHEP, Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. Harvard Univ, Cambridge, MA 02139 USA. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. World Lab, FBLJA Project, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Univ Sci & Technol China, USTC, Hefei 230029, Anhui, Peoples R China. SEFT, Res Inst High Energy Phys, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. ITEP, Inst Theoret & Expt Phys, Moscow, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, San Diego, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago De Compostela, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, Tuscaloosa, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, PSI, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. High Energy Phys Grp, Taipei, Taiwan. RP Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. RI Fiandrini, Emanuele/C-4549-2008; Rancoita, Pier Giorgio/J-9896-2015; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; D'Alessandro, Raffaello/F-5897-2015; Duran, Ignacio/H-7254-2015; Sanchez, Eusebio/H-5228-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Roth, Stefan/J-2757-2016; Kamyshkov, Yuri/J-7999-2016; Di Lodovico, Francesca/L-9109-2016 OI Rancoita, Pier Giorgio/0000-0002-1990-4283; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; D'Alessandro, Raffaello/0000-0001-7997-0306; Sanchez, Eusebio/0000-0002-9646-8198; Palomares, Carmen/0000-0003-4374-9065; Roth, Stefan/0000-0003-3616-2223; Kamyshkov, Yuri/0000-0002-3789-7152; Di Lodovico, Francesca/0000-0003-3952-2175 NR 1 TC 0 Z9 0 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 21 PY 1998 VL 427 IS 3-4 BP 409 EP 412 DI 10.1016/S0370-2693(98)00396-7 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZX699 UT WOS:000074545100030 ER PT J AU Gehr, RJ Alford, WJ Smith, AV AF Gehr, RJ Alford, WJ Smith, AV TI Simple method of detecting ferroelectric domains with non-phase-matched second-harmonic generation SO APPLIED OPTICS LA English DT Article ID 2ND-HARMONIC GENERATION; GROWN KTIOPO4; MAKER FRINGES; CRYSTALS AB We demonstrate a new method of detecting the presence of ferroelectric domains based on non-phase-matched second-harmonic generation. If a domain boundary is tilted relative to the input and output faces of the crystal, the far-field second-harmonic light consists of multiple beams, in contrast to the single beam generated in a single-domain crystal. The angular separation of the beams provides a measure of the tilt of the domain wall if the refractive-index difference n(2 omega) - n(omega) is known. (C) 1998 Optical Society of America. C1 Sandia Natl Labs, Dept Lasers Opt & Remote Sensing, Albuquerque, NM 87185 USA. RP Gehr, RJ (reprint author), Sandia Natl Labs, Dept Lasers Opt & Remote Sensing, POB 5800, Albuquerque, NM 87185 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1998 VL 37 IS 15 BP 3311 EP 3317 DI 10.1364/AO.37.003311 PG 7 WC Optics SC Optics GA ZM902 UT WOS:000073587800034 PM 18273289 ER PT J AU Jun, BI AF Jun, BI TI Interaction of a pulsar wind with the expanding supernova remnant SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; instabilities; ISM, individual (Crab Nebula); pulsars, general; shock waves; supernova remnants ID CRAB-NEBULA; MAGNETIC-FIELDS; ORIGIN AB Recent Hubble Space Telescope observations of the Crab Nebula show filamentary structures that appear to originate from the Rayleigh-Taylor (R-T) instability operating on the supernova ejects accelerated by the pulsar-driven wind. In order to understand the origin and formation of the filaments in the Crab Nebula, we study the interaction of a pulsar wind with the uniformly expanding supernova remnant by means of numerical simulation. We derive the self-similar solution of this model for a general power-law density profile of supernova ejecta. By performing two-dimensional numerical simulations, we nd three independent instabilities in the interaction region between the pulsar wind and the expanding supernova remnant. The first weak instability occurs in the very beginning and is caused by the impulsive acceleration of supernova ejecta by the pulsar wind. The second instability occurs in the postshock flow (shock wave driven by pulsar bubble) during the intermediate stage. This second instability develops briefly while the gradients of density and pressure are of opposite signs (satisfying the criterion of the R-T instability). The third and most important instability develops as the shock driven by the pulsar bubble becomes accelerated (r proportional to t(6/5)). This is the strongest instability and produces pronounced filamentary structures that resemble the observed filaments in the Crab Nebula. Our numerical simulations can reproduce important observational features of the Crab Nebula. The high-density heads in the R-T fingertips are produced because of the compressibility of the gas. The density of these heads is found to be about 10 times higher than other regions in the fingers. The mass contained in the R-T fingers is found to be 60%-75% of the total shocked mass, and the kinetic energy within the R-T fingers is 55%-72% of the total kinetic energy of the shocked flow. The R-T fingers are found to accelerate with a slower rate than the shock front, which is consistent with the observations. By comparing our simulations and the observations, we infer that the some finger-like filaments (region F or G in Hester's observations) started to develop about 657 yr ago. C1 Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. RP Jun, BI (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-630, Livermore, CA 94551 USA. NR 20 TC 50 Z9 50 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 282 EP 293 DI 10.1086/305627 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100025 ER PT J AU Deupree, RG AF Deupree, RG TI Stellar evolution with arbitrary rotation laws. III. Convective core overshoot and angular momentum distribution SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; hydrodynamics; stars, evolution; stars, interiors; stars, rotation ID TURBULENT-DIFFUSION; STARS; MODELS; DIAGRAM; OPACITY; FLOW AB Intermingled two-dimensional hydrodynamic and two-dimensional stellar evolution calculations are presented for two 8.75 M. models, one nonrotating and one rotating with a zero-age main sequence surface equatorial rotational velocity of 200 km s(-1). The first calculation of the rotating model was made assuming no convective core overshooting and enforcing solid-body rotation in the convective core. Hydrodynamic simulations at various stages of core hydrogen burning indicate that neither of these assumptions is true. Overshooting to a distance equivalent to about 0.35 pressure scale heights is found, and there is some evidence that the distance in terms of the pressure scale height increases slightly in later stages of core hydrogen burning. This is not a claim that the pressure scale height is a relevant parameter for determining overshooting distances. The dynamic calculations also show that the rotation rate in the convective core is approximately constant on cylinders and that the rate may be expressed as a power law in the distance from the rotation axis, as long as there is a cutoff at small distances. Two more evolutionary sequences, one rotating and one not, were calculated utilizing these results. The largest effects are produced from the overshooting and are esssentially those found by previous researchers. However, the angular momentum distribution in the interior at the end of core hydrogen burning is significantly different for this second case than for the one assuming solid-body rotation in the convective core. The primary differences are that the horizontal variation in the rotation rate is much larger and that the rotation rate near the center is much higher in the second case. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Deupree, RG (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,DX-7,MS-P947, Los Alamos, NM 87545 USA. NR 34 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 340 EP 347 DI 10.1086/305605 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100031 ER PT J AU Alcock, C Allsman, RA Alves, D Ansari, R Aubourg, E Axelrod, TS Bareyre, P Beaulieu, JP Becker, AC Bennett, DP Brehin, S Cavalier, F Char, S Cook, KH Ferlet, R Fernandez, J Freeman, KC Griest, K Grison, P Gros, M Gry, C Guibert, J Lachieze-Rey, M Laurent, B Lehner, MJ Lesquoy, E Magneville, C Marshall, SL Maurice, E Milsztajn, A Minniti, D Moniez, M Moreau, O Moscoso, L Palanque-Delabrouille, N Peterson, BA Pratt, MR Prevot, L Queinnec, F Quinn, PJ Renault, C Rich, J Spiro, M Stubbs, CW Sutherland, W Tomaney, A Vandehei, T Vidal-Madjar, A Vigroux, L Zylberajch, S AF Alcock, C Allsman, RA Alves, D Ansari, R Aubourg, E Axelrod, TS Bareyre, P Beaulieu, JP Becker, AC Bennett, DP Brehin, S Cavalier, F Char, S Cook, KH Ferlet, R Fernandez, J Freeman, KC Griest, K Grison, P Gros, M Gry, C Guibert, J Lachieze-Rey, M Laurent, B Lehner, MJ Lesquoy, E Magneville, C Marshall, SL Maurice, E Milsztajn, A Minniti, D Moniez, M Moreau, O Moscoso, L Palanque-Delabrouille, N Peterson, BA Pratt, MR Prevot, L Queinnec, F Quinn, PJ Renault, C Rich, J Spiro, M Stubbs, CW Sutherland, W Tomaney, A Vandehei, T Vidal-Madjar, A Vigroux, L Zylberajch, S TI EROS and MACHO combined limits on planetary-mass dark matter in the galactic halo SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; gravitational lensing; stars, low-mass, brown dwarfs ID OBJECTS AB The EROS and MACHO collaborations have each published upper limits on the amount of planetary-mass dark matter in the Galactic halo obtained from gravitational microlensing searches. In this Letter, the two limits are combined to give a much stronger constraint on the abundance of low-mass MACHOs. Specifically, objects with masses 10(-7) M. less than or similar to m less than or similar to 10(-3) M. make up less than 25% of the halo dark matter for most models considered, and less than 10% of a standard spherical halo is made of MACHOs in the 3.5 x 10(-7) M. < m < 4.5 x 10(-5) M. mass range. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, Supercomp Facil, Canberra, ACT 0200, Australia. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Paris Sud, CNRS, IN2P3, Lab Accelerateur Lineaire, F-91405 Orsay, France. Ctr Etud Saclay, DAPNIA, DSM, CEA, F-91191 Gif Sur Yvette, France. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Coll France, Phys Corpusculaire Lab, CNRS, IN2P3,LA 41,Lab Associe, F-75231 Paris 05, France. CNRS, INSU, Inst Astrophys Paris, F-75014 Paris, France. Kapleyn Astron Inst, NL-9700 AV Groningen, Netherlands. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ La Serena, Fac Ciencias, Dept Fis, La Serena, Chile. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Lab Astron Spatiale Marseille, F-13120 Marseille, France. Observ Paris, INSU, Ctr Anal Images, F-75014 Paris, France. Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. Observ Marseille, F-13248 Marseille 04, France. MIT, Ctr Space Res, Cambridge, MA 02139 USA. European So Observ, D-85748 Garching, Germany. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. RP Alcock, C (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Quinn, Peter/B-3638-2013; Stubbs, Christopher/C-2829-2012; OI Stubbs, Christopher/0000-0003-0347-1724; Lehner, Matthew/0000-0003-4077-0985 NR 10 TC 102 Z9 103 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP L9 EP L12 DI 10.1086/311355 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ839 UT WOS:000073908200003 ER PT J AU Newberg, HJ Yanny, B AF Newberg, HJ Yanny, B TI An absence of gaps in the main-sequence population of field stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : stellar content; Hertzsprung-Russell diagram; stars : fundamental parameters ID A-STARS; CLASSIFICATION; PHOTOMETRY; DIAGRAM AB Using high-precision parallaxes from the Hipparcos catalog, we construct H-R diagrams for two samples of bright stars. The first is a magnitude-limited sample that is over 90% complete and uses uniform photometry from the Catalog of WBVR Magnitudes of Northern Sky Bright Stars (delta > -14 degrees). This sample shows a smooth distribution of stars along the main sequence, with no detectable gaps. The second contains all of the stars closer than 100 pc in the Hipparcos catalog with delta < -12 degrees. Uniform spectroscopy from the Michigan Spectral Survey shows that some stars that appear on the main sequence in the H-R diagram, particularly those in the 0.2 < B - V < 0.3 region that has been labeled the Bohm-Vitense gap, are classified as giants by the MK system of spectral classification. Other gaps that have been identified in the main sequence are also affected by such classification criteria. This analysis casts doubt on the existence of the Bohm-Vitense gap, which is thought to result from the sudden onset of,convection in stars. The standard identification of main-sequence stars with luminosity class V and giants with luminosity class III must be reconsidered for some spectral types. The true nature of the stars that lie on the main sequence in the H-R diagram but do not have luminosity class V designations remains to be investigated. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Yanny, B (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 28 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP L57 EP L60 DI 10.1086/311336 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ839 UT WOS:000073908200014 ER PT J AU Buchko, GW Rozek, A Hoyt, DW Cushley, RJ Kennedy, MA AF Buchko, GW Rozek, A Hoyt, DW Cushley, RJ Kennedy, MA TI The use of sodium dodecyl sulfate to model the apolipoprotein environment. Evidence for peptide-SDS complexes using pulsed-field-gradient NMR spectroscopy SO BIOCHIMICA ET BIOPHYSICA ACTA-LIPIDS AND LIPID METABOLISM LA English DT Article DE apolipoprotein; micelle; NMR spectroscopy; diffusion coefficient ID PLASMA LIPOPROTEINS; MEMBRANE-PROTEINS; MICELLES; CONFORMATION; ASSOCIATION; H-1-NMR AB Pulsed-field-gradient NMR spectroscopy was used to measure translational diffusion coefficients (D-s) for a peptide corresponding to a proposed lipid-binding domain of human apolipoprotein C-I, residues 7-24 (apoC-I(7-24)). Diffusion coefficients for apoC-I(7-24) were determined directly by following the decay of the resonance intensity of selected peptide protons at various concentrations of sodium dodecyl sulfate (SDS), a detergent increasingly being used to model the apolipoprotein environment. Previously, diffusion coefficients of peptides in the presence of SDS have been determined indirectly by monitoring the SDS diffusion coefficient. The direct measurement of the diffusion coefficient of the peptide enables one to distinguish whether SDS simply coats the peptide's surface to produce a uniformly charged 'rod' or if the peptide associates with a micelle. Using the direct method, at SDS concentrations above 5 mM (which is below the SDS critical micelle concentration (8.1 mM)), apoC-I(7-24) exhibited diffusion coefficients consistent with the formation of a large-molecular-weight complex. Based on the ratio of the diffusion coefficients for free-and SDS-associated peptide, the molecular weight of the peptide-SDS complex was much larger than a factor of 1.4, the increase in molecular weight of the free peptide predicted if apoC-I(7-24) was uniformly surface coated with SDS. (C) 1998 Elsevier Science B.V. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Simon Fraser Univ, Inst Mol Biol & Biochem, Burnaby, BC V5A 1S6, Canada. RP Kennedy, MA (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. EM ma_kennedy@pnl.gov RI Hoyt, David/H-6295-2013; Buchko, Garry/G-6173-2015 OI Buchko, Garry/0000-0002-3639-1061 NR 41 TC 24 Z9 24 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0005-2760 J9 BBA-LIPID LIPID MET JI Biochim. Biophys. Acta-Lipids Lipid Metab. PD MAY 20 PY 1998 VL 1392 IS 1 BP 101 EP 108 DI 10.1016/S0005-2760(98)00028-9 PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ZT025 UT WOS:000074040100009 PM 9593844 ER PT J AU Curtis, RA Montaser, A Prausnitz, JM Blanch, HW AF Curtis, RA Montaser, A Prausnitz, JM Blanch, HW TI Protein-protein and protein-salt interactions in aqueous protein solutions containing concentrated electrolytes (vol 57, pg 11, 1997) SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Correction C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Curtis, RA (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 1 TC 7 Z9 7 U1 2 U2 9 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD MAY 20 PY 1998 VL 58 IS 4 BP 451 EP 451 DI 10.1002/(SICI)1097-0290(19980520)58:4<451::AID-BIT13>3.0.CO;2-E PG 1 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA ZC889 UT WOS:000072629200013 ER PT J AU Knoll, DA AF Knoll, DA TI An improved convection scheme applied to recombining divertor plasma flows SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE high-order convective differencing; Newton-Krylov methods; tokamak divertor plasma ID KRYLOV METHODS; EQUATIONS; ALGORITHM; TRANSPORT; SIMULATION; SYSTEMS AB A high-order finite volume convection scheme, in conjunction with a monotonicity preserving flux-limiter is applied to a combined tokamak edge plasma/Navier-Stokes neutral transport model. This is a highly nonlinear system of convection-diffusion-reaction equations which describe the partially ionized boundary layer plasma of a tokamak fusion reactor. The solutions of interest contain a sharp ionization front. The improved convective discretization is applied within the context of the existing matrix-free Newton-Krylov solution algorithm. More accurate convective differencing is shown to make a significant difference on a problem of current interest. It is demonstrated that a matrix-free Newton-Krylov implementation, where the preconditioner is derived using first-order upwind convective differencing, provides savings in both memory requirements and CPU time. (C) 1998 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Knoll, DA (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, POB 1663, Los Alamos, NM 87545 USA. NR 21 TC 11 Z9 12 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 20 PY 1998 VL 142 IS 2 BP 473 EP 488 DI 10.1006/jcph.1998.5947 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZR640 UT WOS:000073999000008 ER PT J AU Caramana, EJ Shashkov, MJ AF Caramana, EJ Shashkov, MJ TI Elimination of artificial grid distortion and hourglass-type motions by means of Lagrangian subzonal masses and pressures SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article AB The bane of Lagrangian hydrodynamics calculations is the premature breakdown of grid topology that results in severe degradation of accuracy and run termination often long before the assumption of a Lagrangian zonal mass has ceased to be valid. At short spatial grid scales this is usually referred to by the terms "hourglass" mode or "keystone" motion associated, in particular, with underconstrained grids such as quadrilaterals and hexahedrons in two and three dimensions, respectively. At longer spatial lengths relative to the grid spacing there is what is referred to ubiquitously as "spurious vorticity," or the long-thin zone problem. In both cases the result is anomalous grid distortion and tangling that has nothing to do with the actual solution, as would be the case for turbulent flow. In this work we show how such motions can be eliminated by the proper use of subzonal Lagrangian masses, and associated densities and pressures. These subzonal pressures give rise to forces that resist these spurious motions. The pressure is no longer a constant in a zone; it now accurately reflects the density gradients that can occur within a zone due to its differential distortion. Subzonal Lagrangian masses can be choosen in more than one manner to obtain subzonal density and pressure variation. However, these masses arise in a natural way from the intersection of the Lagrangian contours, through which no mass flows, that are associated with both the Lagrangian zonal and nodal masses in a staggered spatial grid hydrodynamics formulation. This is an extension of the usual Lagrangian assumption that is often applied to only the zonal mass. We show that with a proper discretization of the subzonal forces resulting from subzonal pressures, hourglass motion and spurious vorticity can be eliminated for a very large range of problems. (C) 1998 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Theoret,Appl Theoret & Computat Phys Div, Math Modelling & Anal Grp MSB284, Hydrodynam Methods Grp MSD413, Los Alamos, NM 87545 USA. RP Caramana, EJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret,Appl Theoret & Computat Phys Div, Math Modelling & Anal Grp MSB284, Hydrodynam Methods Grp MSD413, Los Alamos, NM 87545 USA. NR 22 TC 91 Z9 108 U1 0 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 20 PY 1998 VL 142 IS 2 BP 521 EP 561 DI 10.1006/jcph.1998.5952 PG 41 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZR640 UT WOS:000073999000011 ER PT J AU Mukerjee, S McBreen, J AF Mukerjee, S McBreen, J TI Effect of particle size on the electrocatalysis by carbon-supported Pt electrocatalysts: an in situ XAS investigation SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE carbon-supported Pt; electrocatalysis; particle size; X-ray absorption spectroscopy; methanol oxidation ID X-RAY-ABSORPTION; OXYGEN REDUCTION; PLATINUM PARTICLES; ELECTRONIC-STRUCTURE; METAL-CATALYSTS; OXIDATION; METHANOL; ACID; CLUSTERS; ALLOYS AB In situ X-ray absorption studies were done in 1M HClO4 with and without 0.3 M MeOH, on several well-defined carbon-supported Pt electrocatalysts with particle sizes in the range of 25 to 90 Angstrom. Data were obtained at several potentials in the range of 0.0 to 1.14V vs. RHE. The results show that as the particle size is reduced below 50 Angstrom, the strength of adsorption of H, OH and C-1, moieties such as CO is increased. The strong adsorption of OH explains the reduced specific activity for oxygen reduction on small particles. The reduced activity for methanol oxidation on the small particles is due to a combination of the increased strength of adsorption of both CO and OH. The strong adsorption of H at negative potentials on small Pt particles is sufficient to induce reconstruction and morphological changes in the Pt particles. Both XANES and EXAFS data on a 53 Angstrom particle at 0.84V indicate that formation of PtOH is the rate determining step in the oxidation of methanol. All these affects are due to an increase in the number of Pt sites with low coordination on the small particles. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP McBreen, J (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. EM MCBREEN@BNLARM.BNL.GOV NR 36 TC 281 Z9 284 U1 14 U2 71 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD MAY 20 PY 1998 VL 448 IS 2 BP 163 EP 171 DI 10.1016/S0022-0728(97)00018-1 PG 9 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 112CB UT WOS:000075475600003 ER PT J AU Markovic, NM Grgur, BN Lucas, CA Ross, PN AF Markovic, NM Grgur, BN Lucas, CA Ross, PN TI Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE lead; underpotential deposition; Pt(111); bromine anions; RRDE; surface X-ray scattering ID ACID-SOLUTIONS; EX-SITU; IN-SITU; COPPER; PLATINUM(111); CU; ADSORPTION; ELECTRODES; ANIONS; LEED AB The underpotential deposition (upd) of Pb onto Pt(lll) in solution containing Br- was examined by classical RRDP(111)E electrochemical methods in combination with in situ surface X-ray scattering measurements. The results show that Pb upd onto Pt(lll) in the presence of bromide is a competitive process with the total amount of Pb deposited at underpotential being only ca. 0.51 +/- 5% ML, less than the amount needed to form a close-packed monolayer, 0.63 ML (1 ML equals 1 Pb atom per Pt surface atom). Deposition of Pb adatoms is accompanied by desorption of about one-half of the bromide adsorbed on the Pt surface at higher potentials, leaving co-adsorbed bromide both in and on-top-of the adlayer. In the potential region where the ratio of co-adsorbed species is close to one (E approximate to OV) there is the slow formation (over a period of ca. 2h) of an ordered surface alloy, which has a p(2 x 2) unit cell. No other ordered structures of Pb are observed in the underpotential region. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Markovic, NM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. OI Grgur, Branimir/0000-0003-4684-9053 NR 21 TC 8 Z9 8 U1 0 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD MAY 20 PY 1998 VL 448 IS 2 BP 183 EP 188 DI 10.1016/S0022-0728(97)00012-0 PG 6 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 112CB UT WOS:000075475600005 ER PT J AU Wang, JX Adzic, RR AF Wang, JX Adzic, RR TI Surface reconstruction at metal vertical bar solid polymer electrolyte interfaces: Au(111)vertical bar Nafion (R) interface SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE surface reconstruction; Nafion (R); Au(111); solid polymer electrolyte interface; ion permselectivity; grazing incident angle X-ray diffraction ID X-RAY-SCATTERING; CRYSTALLOGRAPHIC ORIENTATION; AU(111) SURFACE; NAFION(R); ELECTROCHEMISTRY; INSITU; CATION; FILMS; BLUE AB The structure of the Au(lll) surface in contact with a recast Nafion(R) film has been studied as a function of potential by using grazing incident angle X-ray diffraction. The high penetration depth of X-ray makes it possible to probe the electrode surface covered by a 1 to 3 mu m thick Nafion(R) film. The Nafion(R)-coated Au(lll) electrode surface is not reconstructed at open circuit potential. However, the (23 x root 3) reconstruction can be generated at sufficiently negative potentials. In comparison with the Au(lll) electrode in NaClO4 solution, the lifting of reconstruction is shifted positively by about 0.2 V. This fact supports the view of the primary effect of surface charge on the Au(lll) reconstruction lifting. Adding chloride to the solution shifts the phase transition potential negatively after several hours, indicating a moderate ion permselectivity of the Nafion(R) film in NaCl solution. These results demonstrate that the Nafion(R) coating is stable over a large potential range and is suitable for studying surface properties and the effects of ion distribution on surface electrochemical processes at single crystal surfaces. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Chem Sci, Upton, NY 11973 USA. RP Adzic, RR (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Chem Sci, Upton, NY 11973 USA. EM adzic@solids.phy.bnl.gov RI Wang, Jia/B-6346-2011 NR 31 TC 14 Z9 14 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD MAY 20 PY 1998 VL 448 IS 2 BP 205 EP 210 DI 10.1016/S0022-0728(97)00033-8 PG 6 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 112CB UT WOS:000075475600007 ER PT J AU Berkowitz, CM Fast, JD Springston, SR Larsen, RJ Spicer, CW Doskey, PV Hubbe, JM Plastridge, R AF Berkowitz, CM Fast, JD Springston, SR Larsen, RJ Spicer, CW Doskey, PV Hubbe, JM Plastridge, R TI Formation mechanisms and chemical characteristics of elevated photochemical layers over the northeast United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INCREMENTAL HYDROCARBON REACTIVITY; NONMETHANE HYDROCARBONS; OZONE AB The chemical composition of layers of trace gas mixtures within the lower troposphere and their relationship to surface trace gas concentrations are investigated using airborne chemistry and meteorological measurements made over eastern Connecticut and central Massachusetts. Layers of photochemically aged material were identified by maxima above the surface stable layer in the profiles of O-3, NOy, CO, aerosols, peroxyacetyl nitrate (PAN), and the ratio of highly to lesser reactive hydrocarbons (e.g., benzene and toluene). Observations suggest that strong diurnal variations in surface-ozone mixing ratios are associated with elevated layers of ozone and other trace gases. The elevated layers were also associated with strong gradients of NOx both vertically, across the mixed layer, and horizontally, between urban and rural regions, providing evidence for the dominant role of localized anthropogenic NO, emissions over North America on ozone production in urban regions. On days when elevated layers were detected, isoprene's late-morning propene-equivalent mixing ratio (a measure of nonmethane hydrocarbon reactivity with OH) was an order of magnitude greater than that of the next most reactive species up to an altitude of 650 m mean sea level. Four-dimensional data assimilation was used within a mesoscale model to study the formation mechanism and history of these layers, with a key result being that no unique "age" or source region could generally be attributed to these layers as a consequence of turbulent mixing and transport leading to their formation. C1 Pacific NW Lab, Richland, WA 99352 USA. US DOE, Environm Measurements Lab, New York, NY 10014 USA. Battelle Mem Inst, Columbus, OH 43201 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Berkowitz, CM (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. EM cm_berkowitz@pnl.gov; jd_fast@pnl.gov; srspringston@bnl.gov; larsenr@eml.doe.gov; spicerc@battelle.org; pvdoskey@anl.gov; jm_hubbe@pnl.gov; plastridger@battelle.org NR 31 TC 23 Z9 23 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1998 VL 103 IS D9 BP 10631 EP 10647 DI 10.1029/97JD03751 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZN676 UT WOS:000073670500007 ER PT J AU Franzen, S Roach, MP Chen, YP Dyer, RB Woodruff, WH Dawson, JH AF Franzen, S Roach, MP Chen, YP Dyer, RB Woodruff, WH Dawson, JH TI The unusual reactivities of Amphirite ornata dehaloperoxidase and Notomastus lobatus chloroperoxidase do not arise from a histidine imidazolate proximal heme iron ligand SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CYTOCHROME-C PEROXIDASE; POLYCHAETE AMPHITRITE ORNATA; RESONANCE RAMAN; HORSERADISH-PEROXIDASE; LINKED IONIZATION; MYOGLOBIN; SPECTROSCOPY; ASSIGNMENT; HEMOGLOBIN; RESOLUTION AB Notomastus lobatus chloroperoxidase (NCPO) and Amphitrite ornata dehaloperoxidase (DHP) catalyze the halogenation of phenols and dehalogenation of halophenols, respectively. Both enzymes require peroxide for activity and have recently been shown to contain histidine (His) as their proximal heme iron ligand, DHP is the only heme enzyme known to catalyze peroxide-dependent defluorination reactions, and NCPO is the first His-Ligated heme-containing peroxidase capable of chlorinating halogen accepters using chloride as the halogen donor. To probe the roles of the proximal His ligands in the mechanism of action of these two novel peroxidases, they have been examined by resonance Raman and infrared spectroscopy to determine the vibrational properties of their deoxyferrous and ferrous-CO derivatives. Previous studies of His-Ligated heme proteins have revealed characteristic distinctions between dioxygen-binding globins and peroxidases. In the latter, the spectral properties are indicative of strong hydrogen bonding of the His imidazole N-1 hydrogen, giving histidinate character to the His, whereas the globins are thought to contain a predominately neutral His. The partially anionic peroxidase proximal His is thought to facilitate O-O bond cleavage of bound peroxide en route to the key oxo-ferryl compound I peroxidase intermediate. Surprisingly, the vibrational data reported herein for DHP and NCPO are similar to those previously reported for neutral His/imidazole-ligated globins and heme complexes. The vibrational data indicate that these enzymes do not activate bound peroxide through a mechanism dependent on a push effect imparted by a partially ionized proximal histidine as proposed for typical heme peroxidases. C1 Univ Calif Los Alamos Natl Lab, Biosci & Biotechnol Grp, Los Alamos, NM 87545 USA. Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. Univ S Carolina, Sch Med, Columbia, SC 29208 USA. RP Woodruff, WH (reprint author), Univ Calif Los Alamos Natl Lab, Biosci & Biotechnol Grp, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 54 Z9 54 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 20 PY 1998 VL 120 IS 19 BP 4658 EP 4661 DI 10.1021/ja973212d PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA ZP974 UT WOS:000073807700014 ER PT J AU Christe, KO Wilson, WW Drake, GW Dixon, DA Boatz, JA Gnann, RZ AF Christe, KO Wilson, WW Drake, GW Dixon, DA Boatz, JA Gnann, RZ TI Pentagonal planar AX(5) species: Synthesis and characterization of the iodine(III) pentafluoride dianion, IF52- SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID EFFECTIVE CORE POTENTIALS; COMPACT EFFECTIVE POTENTIALS; DENSITY FUNCTIONAL THEORY; ALKALI-METAL FLUORIDES; EXPONENT BASIS-SETS; MOLECULAR CALCULATIONS; 1ST EXAMPLE; EFFICIENT; ANION; ATOMS AB The new IF52- dianion, which is only the second known example of a pentagonal planar AX(5) species, was prepared as its N(CH3)(4)(+) salt from N(CH3)(4)LF4 and N(CH3)(4)F in CH3CN solution. Its structure was established by infrared and Raman spectroscopy, ab initio calculations, and a comparison to isoelectronic XeF5-. Furthermore, vibrational spectroscopy and X-ray powder diffraction data show that the previously reported composition "Cs3IF6" is actually a mixture of Cs2IF5 and CsF. Ab inito calculations also show that the most probable geometries for the free LF63- ion are vibrationally unstable and undergo spontaneous F- ion loss with formation of either pentagonal planar IF52- or square planar IF4-. The synthesis and some properties of the new N(CH3)(4)IF4 salt and a revised normal coordinate analysis of XeF5- are also presented. C1 USAF, Res Lab, Hughes STX, Propuls DIrectorate, Edwards AFB, CA 93524 USA. Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Pacific NW Lab, Richland, WA 99352 USA. RP USAF, Res Lab, Hughes STX, Propuls DIrectorate, Edwards AFB, CA 93524 USA. RI Christe, Karl/O-4885-2014 OI Christe, Karl/0000-0003-0661-5519 NR 53 TC 25 Z9 25 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 20 PY 1998 VL 120 IS 19 BP 4711 EP 4716 DI 10.1021/ja980057+ PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA ZP974 UT WOS:000073807700020 ER PT J AU Song, XD Nolan, J Swanson, BI AF Song, XD Nolan, J Swanson, BI TI Optical signal transduction triggered by protein-ligand binding: Detection of toxins using multivalent binding SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CHOLERA-TOXIN; PROJECTED STRUCTURE; MEMBRANE-RECEPTORS; B-SUBUNIT; GANGLIOSIDE; COMPLEXES; AFFINITY; KINETICS; SURFACE; GM1 C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Song, XD (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 28 TC 51 Z9 52 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 20 PY 1998 VL 120 IS 19 BP 4873 EP 4874 DI 10.1021/ja980246s PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZP974 UT WOS:000073807700043 ER PT J AU Kim, JT Kang, WN Lim, HR Kim, DH Park, YK Park, JC Kim, CH Hahn, TS Choi, SS Hettinger, JD Gray, KE AF Kim, JT Kang, WN Lim, HR Kim, DH Park, YK Park, JC Kim, CH Hahn, TS Choi, SS Hettinger, JD Gray, KE TI Pinning effect on critical dynamics in YBa2Cu3O7-delta films with inherent random disorder and with columnar defects SO PHYSICA C LA English DT Article DE YBCO films; conductivity; crystal ID CRITICAL-BEHAVIOR; SINGLE-CRYSTALS; HEAT; LINE AB The in-plane longitudinal resistivities of YBa2Cu3O7-delta (YBCO) films before and after Sn ion irradiation of a matching field 1 T have been measured as a function of magnetic field H (less than or equal to 6 T) and temperature T. The extracted fluctuation part of the conductivity sigma(xx)* (T, H) of the unirradiated sample with inherent random disorder exhibits 3D-XY scaling behavior that reveals dynamic critical exponent z = 1.86 +/- 0.1 and nu approximate to 0.669. The inherent random disorder increases the dynamic critical exponent z to 1.86 +/- 0.1 from the value of 1.5 that is for detwinned YBCO single crystal. After the irradiation, the fluctuation conductivity enhanced by the strong pinning of vortex shows deviation from the scaling behavior for the unirradiated one, suggesting that the critical dynamics is strongly perturbed by the strong pinning due to columnar defects. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Korea Res Inst Stand & Sci, Superconduct Grp, Taejon 305600, South Korea. Korea Inst Sci & Technol, Superconduct Res Grp, Seoul 130650, South Korea. Yeungnam Univ, Dept Phys, Kyongsan 712749, South Korea. Argonne Natl Lab, Argonne, IL 60439 USA. RP Kim, JT (reprint author), Korea Res Inst Stand & Sci, Superconduct Grp, POB 102, Taejon 305600, South Korea. NR 17 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 20 PY 1998 VL 301 IS 1-2 BP 99 EP 103 DI 10.1016/S0921-4534(98)00160-9 PG 5 WC Physics, Applied SC Physics GA ZU995 UT WOS:000074257500012 ER PT J AU Thompson, TM Mark, BL Gray, CW Terwilliger, TC Sreerama, N Woody, RW Gray, DM AF Thompson, TM Mark, BL Gray, CW Terwilliger, TC Sreerama, N Woody, RW Gray, DM TI Circular dichroism and electron microscopy of a core Y61F mutant of the f1 gene 5 single-stranded DNA-binding protein and theoretical analysis of CD spectra of four Tyr -> Phe substitutions SO BIOCHEMISTRY LA English DT Article ID NUCLEIC-ACID COMPLEXES; V-PROTEIN; FILAMENTOUS BACTERIOPHAGE; DEOXYRIBONUCLEIC-ACID; FD GENE-5-PROTEIN; POLYNUCLEOTIDES; H-1-NMR; HELIX; IKE; M13 AB A core Y61F mutant of the gene 5 single-stranded DNA-binding protein (g5p) of fl bacterial virus aggregated when expressed from a plasmid, but, after refolding in vitro, it behaved much like wildtype and may be a stability or folding mutant. Circular dichroism (CD) titrations showed the same cooperative polynucleotide binding modes for Y61F and wild-type g5p, There are n = 4 and n congruent to 2.5 modes for binding to poly[d(A)] at low ionic strengths, but n = 4, n = 3, and n congruent to 2-2.5 modes for binding to fd single-stranded viral DNA (fd ssDNA), where n is the number of nucleotides occluded by each bound g5p monomer in a given mode, Y61F g5p has slightly reduced affinity in the n = 4 mode. Electron microscopy showed that Y61F g5p forms left-handed nucleoprotein superhelices indistinguishable from wild-type. Progression from binding to fd ssDNA in the n = 4 to n = 3 to n congruent to 2-2.5 mode is accompanied by an increase in the number of helical turns, an increase from (7.7 +/- 0.3) to (9.5 +/- 0.3) to (similar to 10-13) g5p dimers per turn, and a decrease in the number of DNA nucleotides per rum. From CD spectra for four of five possible Y --> F g5p mutants, we infer that the fifth tyrosine, Tyr 56, contributes strongly to the CD, Retention of a strong 229 nm CD band in all mutants indicates that all retain elements of the native structure. Spectra of Y26F, Y34F, and Y61F g5p imply limited mobility of the replacement Phe. Comparison of measured with calculated CD spectra also suggests limited mobility for Tyr 26 and Tyr 34 in g5p in solution, and provides new information that the g5p structure in solution may be dominated by Tyr 41 rotamers differing from that stabilized in the crystal. C1 Univ Texas, Dept Mol & Cell Biol, Richardson, TX 75083 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Colorado State Univ, Dept Biochem & Mol Biol, Ft Collins, CO 80523 USA. RP Gray, CW (reprint author), Univ Texas, Dept Mol & Cell Biol, Mail Stn FO31,Box 830688, Richardson, TX 75083 USA. EM cwgray@utdallas.edu; rww@lamar.ColoState.edu RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 FU NIGMS NIH HHS [GM38714, GM22994, GM34293] NR 65 TC 24 Z9 24 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 19 PY 1998 VL 37 IS 20 BP 7463 EP 7477 DI 10.1021/bi972545k PG 15 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZP586 UT WOS:000073768300047 PM 9585560 ER PT J AU Srinivasan, C Posewitz, MC George, GN Winge, DR AF Srinivasan, C Posewitz, MC George, GN Winge, DR TI Characterization of the copper chaperone Cox17 of Saccharomyces cerevisiae SO BIOCHEMISTRY LA English DT Article ID CYTOCHROME-C-OXIDASE; ABSORPTION FINE-STRUCTURE; CRYSTAL-STRUCTURE; IDENTIFICATION; SPECTROSCOPY; OXIDATION; CHEMISTRY; COMPLEXES; MEMBRANE; OXYGEN AB Assembly of functional cytochrome oxidase in yeast requires Cox17, which has been postulated to deliver copper ions to the mitochondrion for insertion into the enzyme. This role for Cox17 is supported by the observation that it binds copper as a binuclear cuprous-thiolate cluster. X-ray absorption spectroscopy, together with UV-visible absorption and emission spectroscopy, indicates the presence of bound cuprous ions, trigonally coordinated by thiolate ligands. Analysis of the EXAFS shows three Cu-S bonds at 2.26 Angstrom, plus a short Cu-Cu distance of 2.7 Angstrom, indicating a binuclear cluster in Cox17. The cuprous-thiolate cluster in Cox17 is substantially more labile than structurally related clusters in metallothioneins. C1 Univ Utah, Hlth Sci Ctr, Salt Lake City, UT 84132 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Winge, DR (reprint author), Univ Utah, Hlth Sci Ctr, Salt Lake City, UT 84132 USA. RI Winge, Dennis/G-3611-2010; George, Graham/E-3290-2013 FU NCI NIH HHS [5P30-CA 42014]; NIEHS NIH HHS [ES 03817] NR 41 TC 94 Z9 96 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 19 PY 1998 VL 37 IS 20 BP 7572 EP 7577 DI 10.1021/bi980418y PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZP586 UT WOS:000073768300059 PM 9585572 ER PT J AU Budzien, JL McCoy, JD Weinkauf, DH LaViolette, RA Peterson, ES AF Budzien, JL McCoy, JD Weinkauf, DH LaViolette, RA Peterson, ES TI Solubility of gases in amorphous polyethylene SO MACROMOLECULES LA English DT Article ID ORGANIC VAPORS; N-ALKANES; MEMBRANES; SORPTION AB The hypothetical polyethylene melt at room temperature is of interest for the purposes of developing the atomic level modeling of gas solubilities in rubbery polymers. In the present study, the gas solubilities in completely amorphous polyethylene are predicted by extrapolating alkane behavior to the long chain limit in a Flory-Huggins context. The results are seen to agree well with a recent simulation study. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP McCoy, JD (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. RI McCoy, John/B-3846-2010; Budzien, Joanne/E-8315-2011; Peterson, Eric/B-9127-2017 OI McCoy, John/0000-0001-5404-1404; Peterson, Eric/0000-0002-2292-4939 NR 29 TC 18 Z9 19 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 19 PY 1998 VL 31 IS 10 BP 3368 EP 3371 DI 10.1021/ma971786x PG 4 WC Polymer Science SC Polymer Science GA ZP498 UT WOS:000073759500029 ER PT J AU Klooster, WT Lu, RS Anwander, R Evans, WJ Koetzle, TF Bau, R AF Klooster, WT Lu, RS Anwander, R Evans, WJ Koetzle, TF Bau, R TI Neutron diffraction study of [Nd(AlMe4)(3)]center dot 0.5Al(2)Me(6) at 100 K: The first detailed look at a bridging methyl group with a trigonal-bipyramidal carbon atom SO ANGEWANDTE CHEMIE-INTERNATIONAL EDITION LA English DT Article DE aluminum; bridging ligands; coordination modes; lanthanides; pentacoordinate carbon ID HIGHLY REACTIVE ORGANOLANTHANIDES; TRANSITION-METAL BONDS; X-RAY; COMPLEXES; CHEMISTRY; HYDROCARBYL; LITHIUM C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. Tech Univ Munich, Inst Anorgan Chem, D-85747 Garching, Germany. RP Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. EM anwander@arthur.anorg.chemie.tu-muenchen.de; wevans@uci.edu; koetzle@chm.chm.bnl.gov; bau@chem1.usc.edu NR 30 TC 41 Z9 41 U1 1 U2 5 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA POSTFACH 101161, 69451 WEINHEIM, GERMANY SN 1433-7851 EI 1521-3773 J9 ANGEW CHEM INT EDIT JI Angew. Chem.-Int. Edit. PD MAY 18 PY 1998 VL 37 IS 9 BP 1268 EP 1270 DI 10.1002/(SICI)1521-3773(19980518)37:9<1268::AID-ANIE1268>3.3.CO;2-P PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA ZW586 UT WOS:000074426500023 ER PT J AU Im, J Krauss, AR Dhote, AM Gruen, DM Auciello, O Ramesh, R Chang, RPH AF Im, J Krauss, AR Dhote, AM Gruen, DM Auciello, O Ramesh, R Chang, RPH TI Studies of metallic species and oxygen incorporation during sputter-deposition of SrBi2Ta2O9 films, using mass spectroscopy of recoiled ions SO APPLIED PHYSICS LETTERS LA English DT Article ID PT/TI AB We have recently developed a mass spectroscopy of recoiled ions technique which is suitable for monolayer-specific surface analysis of thin films during growth. We present initial results using this technique to study the effect of different bottom electrode layers on metallic species and oxygen incorporation in the early stages of SrBi2Ta2O3 (SBT) film growth via ion beam-sputter deposition. The work discussed here has been focused on studying the incorporation of Sr, Bi, and Ta during growth of SET on Pt/Ti/SiO2/Si, Pt/MgO, Ti, and Si substrates. We found that the incorporation of Bi in sputter-deposited SET films depends critically on the bottom electrode surface composition and the growth temperature. (C) 1998 American Institute of Physics. [S0003-6951(98)00920-6]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Northwestern Univ, Dept Mat Sci, Evanston, IL 60208 USA. RP Im, J (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Chang, R.P.H/B-7505-2009 NR 7 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 18 PY 1998 VL 72 IS 20 BP 2529 EP 2531 DI 10.1063/1.121409 PG 3 WC Physics, Applied SC Physics GA ZN118 UT WOS:000073611700011 ER PT J AU Christen, HM Specht, ED Norton, DP Chisholm, MF Boatner, LA AF Christen, HM Specht, ED Norton, DP Chisholm, MF Boatner, LA TI Long-range ferroelectric interactions in KTaO3/KNbO3 superlattice structures SO APPLIED PHYSICS LETTERS LA English DT Article ID DIELECTRIC-PROPERTIES; FILMS; GROWTH; TEMPERATURE; TRANSITION AB Symmetric superlattice structures consisting of alternating atomic-scale layers of KTaO3 and KNbO3 with variable periodicity were grown on KTaO3 substrates by pulsed laser deposition. The in-plane structure of KNbO3 closely matches that of the KTaO3 substrate, resulting in KTaO3/KNbO3 heterostructures that are uniformly strained in-plane without misfit dislocations. This strain imposes an in-plane KNbO3 lattice spacing identical to that of the KTaO3 substrate for the temperature range 30 degrees Cdegrees, produced in the forward direction at the Sp (p) over bar S with root s= 630 GeV, using the UA8 small angle Roman Pot spectrometers. These measurements cover the range in Feynman-x(F) and transverse momentum, 0.6 < x(F) < 1.0 and 0.4 < p(t) < 0.7 GeV, respectively. Within a systematic uncertainty of +/-20% on the absolute cross section measurements, the results are indistinguishable from those made by some of us in two earlier experiments at the CERN Intersecting Storage Rings, with energies, root s = 53 and 62 GeV. In the x(F)-range, 0.6-0.9, the absolute cross sections are lower by a factor of 2 to 3 than the predictions of the Lund model as embodied in the PYTHIA 5.6 and JETSET 7.3 Monte Carlo programs, indicating inadequacies in knowledge of the baryon fragmentation function, For the largest x(F)-range, 0.9-1.0, the measurements agree with the Monte Carlo predictions. We have measured the average <(Lambda)over bar>degrees polarization for our events and find (6+/-12%), consistent with previous measurements at the ISR in the present region of x(F)-p(t). (C) 1998 Elsevier Science B.V. C1 Univ Calif Los Angeles, Los Angeles, CA 90024 USA. CENS, F-91191 Gif Sur Yvette, France. RP Brandt, A (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 16 TC 1 Z9 1 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 18 PY 1998 VL 519 IS 1-2 BP 3 EP 18 DI 10.1016/S0550-3213(98)00168-0 PG 16 WC Physics, Particles & Fields SC Physics GA ZV025 UT WOS:000074260800001 ER PT J AU Dorey, N Hollowood, TJ Khoze, VV Mattis, MP AF Dorey, N Hollowood, TJ Khoze, VV Mattis, MP TI Supersymmetry and the multi-instanton measure - II. From N=4 to N=0 SO NUCLEAR PHYSICS B LA English DT Article ID EFFECTIVE GAUGE-THEORIES; CALCULUS; BREAKING AB Extending recent N = 1 and N = 2 results, we propose an explicit formula for the integration measure on the moduli space of charge-n ADHM multi-instantons in N = 4 supersymmetric SU(2) gauge theory. As a consistency check, we derive a renormalization group relation between the N = 4, N = 2, and N = 1 measures. We then use this relation to construct the purely bosonic ("N = 0") measure as well, in the classical approximation in which the one-loop small-fluctuations determinants is not included. (C) 1998 Elsevier Science B.V. C1 Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. Univ Durham, Ctr Particle Theory, Dept Phys, Durham DH1 3LE, England. Univ Calif Los Alamos Natl Lab, Div Theoret T8, Los Alamos, NM 87545 USA. RP Dorey, N (reprint author), Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. OI Khoze, Valentin V/0000-0003-3006-4147 NR 32 TC 22 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 18 PY 1998 VL 519 IS 1-2 BP 470 EP 482 DI 10.1016/S0550-3213(98)00010-8 PG 13 WC Physics, Particles & Fields SC Physics GA ZV025 UT WOS:000074260800021 ER PT J AU Habib, S Shizume, K Zurek, WH AF Habib, S Shizume, K Zurek, WH TI Decoherence, chaos, and the correspondence principle SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM BROWNIAN-MOTION; WAVE PACKET; CLASSICAL CORRESPONDENCE; LYAPUNOV EXPONENTS; LINEAR-SYSTEMS; PHASE-SPACE; KICKED TOP; ENVIRONMENT; DYNAMICS; STATES AB We present evidence that decoherence can produce a smooth quantum-to-classical transition in nonlinear dynamical systems. High-resolution tracking of quantum and classical evolutions reveals differences in expectation values of corresponding observables. Solutions of master equations demonstrate that decoherence destroys quantum interference in Wigner distributions and washes out fine structure in classical distributions, bringing the two closer together. Correspondence between quantum and classical expectation values is also reestablished. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Lib & Informat Sci, Tsukuba, Ibaraki 305, Japan. RP Habib, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-8,MS B285, Los Alamos, NM 87545 USA. EM habib@lanl.gov; shizume@ulis.ac.jp; whz@lanl.gov NR 47 TC 172 Z9 174 U1 2 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4361 EP 4365 DI 10.1103/PhysRevLett.80.4361 PG 5 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900001 ER PT J AU Tonnison, J Sandorfi, AM Hoblit, S Nathan, AM AF Tonnison, J Sandorfi, AM Hoblit, S Nathan, AM TI First extraction of a spin polarizability of the proton SO PHYSICAL REVIEW LETTERS LA English DT Article ID DELTA-RESONANCE REGION; COMPTON-SCATTERING; MAGNETIC POLARIZABILITIES; PHOTONS AB A proton spin polarizability characterizing backward Compton scattering has been extracted from a dispersion analysis of data between 33 and 309 MeV. This backward spin polarizability, delta(pi) = [27.1 +/- 2.2(stat + syst)(-2.4)(+2.8)(model)] x 10(-4) fm(4), differs significantly from theoretical estimates and suggests a new contribution from the nonperturbative spin structure of the proton. This delta(pi) value removes an apparent inconsistency in the difference of charge polarizabilities extracted from data above pi threshold. Our global result, <(alpha)over bar> - <(beta)over bar> = [10.11 +/- 1.74(stat + syst)(-0.86)(+1.22)(model)] x 10(-4) fm(3), agrees with the previous world average of data below 155 MeV. Our value for <(alpha)over bar> + <(beta)over bar> = [13.23 +/- 0.86(stat + syst)(-0.49)(+0.20)(model)] x 10(-4) fm(3) is consistent with a recent reevaluation of the Baldin sum rule. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Tonnison, J (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 25 TC 60 Z9 61 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4382 EP 4385 DI 10.1103/PhysRevLett.80.4382 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900006 ER PT J AU van Kolck, U Rentmeester, MCM Friar, JL Goldman, T de Swart, JJ AF van Kolck, U Rentmeester, MCM Friar, JL Goldman, T de Swart, JJ TI Electromagnetic corrections to the one-pion-exchange potential SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHARGE-INDEPENDENCE; CHIRAL LAGRANGIANS; COUPLING-CONSTANT; SCATTERING DATA; NUCLEAR-FORCES; BREAKING; QUARKS; MODEL; ANN AB Leading-order electromagnetic loop corrections to the one-pion-exchange potential are computed within the framework of chiral perturbation theory. These corrections generate an effective nucleon-nucleon potential, V-pi gamma, which supplements the sum of one-pion-exchange potential and the nucleon-nucleon Coulomb potential. This potential is charge dependent and its construction is demonstrated to be gauge invariant. The potential V-pi gamma has been included in the Nijmegen partial-wave analysis of np data. A particular renormalization scheme is chosen that lends to a negligible change in the pi(+/-)NN coupling constant and in the np S-1(0) scattering length and effective range. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Flinders Univ S Australia, Dept Phys, Bedford Pk, SA 5042, Australia. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. Univ Nijmegen, Inst Theoret Phys, Nijmegen, Netherlands. RP van Kolck, U (reprint author), Univ Washington, Dept Phys, Seattle, WA 98195 USA. NR 50 TC 67 Z9 67 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4386 EP 4389 DI 10.1103/PhysRevLett.80.4386 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900007 ER PT J AU Liu, Y Wang, XJ Cline, DB Babzien, M Fang, JM Gallardo, J Kusche, K Pogorelsky, I Skaritka, J van Steenbergen, A AF Liu, Y Wang, XJ Cline, DB Babzien, M Fang, JM Gallardo, J Kusche, K Pogorelsky, I Skaritka, J van Steenbergen, A TI Experimental observation of femtosecond electron beam microbunching by inverse free-electron-laser acceleration SO PHYSICAL REVIEW LETTERS LA English DT Article ID GENERATION; RADIATION; GAIN; BNL AB An electron beam microbunched on the optical wavelength scale of approximate to 2.5 mu m by an inverse free electron laser accelerator was observed. The optimum bunching was achieved for a 1% energy modulation of a 32 MeV electron beam with 0.5 GW CO2 laser power. The microbunching process was investigated by measuring the coherent transition radiation produced by the energy modulated electron beam. A quadratic dependence of the transition radiation signal on the electron beam charge was observed. The observed shortest wavelength of coherent transition radiation is less than 2.5 mu m. The debunching process of the microbunched electron beam was experimentally investigated. C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Liu, Y (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90095 USA. OI Gallardo, Juan C/0000-0002-5191-3067 NR 13 TC 65 Z9 66 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4418 EP 4421 DI 10.1103/PhysRevLett.80.4418 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900015 ER PT J AU Marinak, MM Glendinning, SG Wallace, RJ Remington, BA Budil, KS Haan, SW Tipton, RE Kilkenny, JD AF Marinak, MM Glendinning, SG Wallace, RJ Remington, BA Budil, KS Haan, SW Tipton, RE Kilkenny, JD TI Nonlinear Rayleigh-Taylor evolution of a three-dimensional multimode perturbation SO PHYSICAL REVIEW LETTERS LA English DT Article ID 3-DIMENSIONAL SIMULATIONS; SINGLE-MODE; HYDRODYNAMIC INSTABILITIES; 3 DIMENSIONS; LARGE GROWTH; K-SHELL; NOVA; FUSION; IMPLOSIONS; HOT AB The ablation front Rayleigh-Taylor evolution of a well-characterized 3D multimode surface perturbation was measured on a foil accelerated with an x-ray drive as it progressed into the weakly nonlinear regime. The perturbation pattern was locally random and consisted of modes within the first ten harmonics of a 300 mu m square. The pattern evolved into bubbles separated by narrow, interconnecting spike sheets, unambiguously indicating entry into the nonlinear regime. Nonlinear effects occurred when mode amplitudes were relatively small: eta(n) much less than lambda(n)/10. Experimental results are in quantitative agreement with results of our numerical simulations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Marinak, MM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 38 TC 59 Z9 68 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4426 EP 4429 DI 10.1103/PhysRevLett.80.4426 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900017 ER PT J AU Carreras, BA van Milligen, B Pedrosa, MA Balbin, R Hidalgo, C Newman, DE Sanchez, E Frances, M Garcia-Cortes, I Bleuel, J Endler, M Davies, S Matthews, GF AF Carreras, BA van Milligen, B Pedrosa, MA Balbin, R Hidalgo, C Newman, DE Sanchez, E Frances, M Garcia-Cortes, I Bleuel, J Endler, M Davies, S Matthews, GF TI Long-range time correlations in plasma edge turbulence SO PHYSICAL REVIEW LETTERS LA English DT Article ID SELF-ORGANIZED CRITICALITY; DYNAMICS; CONFINEMENT; AVALANCHES; TRANSPORT; SANDPILES AB Analysis of the edge plasma fluctuation in several confinement devices reveals the self-similar character of the fluctuations through the presence of long-range time correlations. These results show that the tail of the autocorrelation function decays as a power law for time lags longer than the decorrelation time and as long as times on the order of the particle diffusion time. The algebraic decay of the long-range time correlations is consistent with plasma transport characterized by self-organized criticality. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Asociac Euratom Ciemat, Madrid 28040, Spain. Max Planck Inst Plasma Phys, EURATOM Assoc, D-85740 Garching, Germany. Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. RP Carreras, BA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Sanchez, Edilberto/D-4620-2009; van Milligen, Boudewijn/H-5121-2015; Garcia-Cortes, Isabel/H-3341-2015; Balbin, Rosa/F-8210-2010 OI Sanchez, Edilberto/0000-0003-1062-7870; van Milligen, Boudewijn/0000-0001-5344-6274; Garcia-Cortes, Isabel/0000-0002-5223-391X; Balbin, Rosa/0000-0001-5231-1300 NR 19 TC 135 Z9 136 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4438 EP 4441 DI 10.1103/PhysRevLett.80.4438 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900020 ER PT J AU Harrison, N Goodrich, RG Vuillemin, JJ Fisk, Z Rickel, DG AF Harrison, N Goodrich, RG Vuillemin, JJ Fisk, Z Rickel, DG TI Quantum interference in LaB6 SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC-BREAKDOWN; FERMI-SURFACE; DEHAAS; KAPPA-(BEDT-TTF)(2)CU(NCS)(2); OSCILLATIONS; PHASE AB Quantum interference effects in the induced currents in metallic LaB6 are investigated in pulsed magnetic fields extending to 60 T and to temperatures of up to 70 K. One of the quantum interference frequencies, corresponding to an area in k space equal to the Brillouin zone, has an effective mass precisely equal to zero. The attenuation of this and other frequencies at high temperatures requires the scattering effects of phonons to be considered within the Boltzmann transport equation. C1 Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. RP Harrison, N (reprint author), Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, MS-E536, Los Alamos, NM 87545 USA. NR 23 TC 17 Z9 17 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4498 EP 4501 DI 10.1103/PhysRevLett.80.4498 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900035 ER PT J AU Petrenko, OA Ritter, C Yethiraj, M Paul, DM AF Petrenko, OA Ritter, C Yethiraj, M Paul, DM TI Investigation of the low-temperature spin-liquid behavior of the frustrated magnet gadolinium gallium garnet SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANTIFERROMAGNET; ORDER; HEAT AB We report the results of powder neutron scattering measurements on the magnetic correlations in the frustrated antiferromagnet Gd3Ga5O12. A clear view of the short-range magnetic order has been obtained for a temperature range 0.14-5 EC. At T similar to 0.14 K there is a partial transition to a phase with a much longer correlation length. We argue that the low-temperature phase is not an ordinary spin glass, as was suggested by bulk properties measurements, but rather a mixture of a spin-liquid state with a set of rigid magnetic pieces nucleated around impurity centers. The experimental data are compared with the results of Monte Carlo simulations performed for several models. C1 Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. Inst Laue Langevin, F-38402 Grenoble, France. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Petrenko, OA (reprint author), Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RI Petrenko, Oleg/E-2717-2013 OI Petrenko, Oleg/0000-0003-1529-303X NR 17 TC 62 Z9 62 U1 2 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4570 EP 4573 DI 10.1103/PhysRevLett.80.4570 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900053 ER PT J AU Chasman, RR AF Chasman, RR TI Comment on "Spins, parity, excitation energies, and octupole structure of an excited superdeformed band in Hg-194 and implications for identical bands" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Chasman, RR (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4610 EP 4610 DI 10.1103/PhysRevLett.80.4610 PG 1 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900063 ER PT J AU Hackman, G Khoo, TL Carpenter, MP Lauritsen, T Lopez-Martens, A Calderin, IJ Janssens, RVF Ackermann, D Ahmad, I Agarwala, S Blumenthal, DJ Fischer, SM Nisius, D Reiter, P Young, J Amro, H Moore, EF Hannachi, F Korichi, A Lee, IY Macchiavelli, AO Dossing, T Nakatsukasa, T AF Hackman, G Khoo, TL Carpenter, MP Lauritsen, T Lopez-Martens, A Calderin, IJ Janssens, RVF Ackermann, D Ahmad, I Agarwala, S Blumenthal, DJ Fischer, SM Nisius, D Reiter, P Young, J Amro, H Moore, EF Hannachi, F Korichi, A Lee, IY Macchiavelli, AO Dossing, T Nakatsukasa, T TI Comment on "Spins, parity, excitation energies, and octupole structure of an excited superdeformed band in Hg-194 and implications for identical bands" - Hackman et al. reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Argonne Natl Lab, Argonne, IL 60439 USA. CNRS, IN2P3, Ctr Spectrometrie Nucl & Spectrometrie Masse, F-91405 Orsay, France. N Carolina State Univ, Raleigh, NC 27695 USA. TUNL, Durham, NC 27708 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Niels Bohr Inst, DK-2100 Copenhagen O, Denmark. UMIST, Manchester M60 1QD, Lancs, England. RP Hackman, G (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Carpenter, Michael/E-4287-2015; Nakatsukasa, Takashi/O-9995-2014 OI Carpenter, Michael/0000-0002-3237-5734; NR 8 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4611 EP 4611 DI 10.1103/PhysRevLett.80.4611 PG 1 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900064 ER PT J AU Goods, SH Neuschwanger, CL Henderson, CC Skala, DM AF Goods, SH Neuschwanger, CL Henderson, CC Skala, DM TI Mechanical properties of CRETE, a polyurethane foam SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE foam; mechanical properties; modulus; collapse stress; energy absorption AB The room-temperature mechanical properties of a closed-cell, polyurethane encapsulant foam were measured as a function of foam density. Over the range of densities examined, the modulus could be described by a power-law relationship with respect to density. This power-law relationship was the same for both tension and compression testing. The basis for this power-law relationship is explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model put forth by Gibson and Ashby. The elastic collapse stress, a property relevant to compression testing, also is found to exhibit a power-law relationship with respect to density. The density dependence of this property is also found in the work of Gibson and Ashby and is explained in terms of the Euler buckling of the struts that comprise the cellular structure. Energy absorption during deformation is also reported for both tension and compression testing. (C) 1998 John Wiley & Sons, Inc. C1 Sandia Natl Labs, Mat Reliabil Dept, Livermore, CA 94551 USA. Sandia Natl Labs, Polymer & Electrochem Technol Dept, Livermore, CA 94551 USA. RP Goods, SH (reprint author), Sandia Natl Labs, Mat Reliabil Dept, 8712,POB 969, Livermore, CA 94551 USA. NR 15 TC 33 Z9 36 U1 4 U2 14 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD MAY 16 PY 1998 VL 68 IS 7 BP 1045 EP 1055 DI 10.1002/(SICI)1097-4628(19980516)68:7<1045::AID-APP2>3.0.CO;2-F PG 11 WC Polymer Science SC Polymer Science GA ZH689 UT WOS:000073137800002 ER PT J AU Proudnikov, D Timofeev, E Mirzabekov, A AF Proudnikov, D Timofeev, E Mirzabekov, A TI Immobilization of DNA in polyacrylamide gel for the manufacture of DNA and DNA-oligonucleotide microchips SO ANALYTICAL BIOCHEMISTRY LA English DT Article DE DNA; gel immobilization; DNA microchips ID GENE-EXPRESSION PATTERNS; CDNA; HYBRIDIZATION; DEPURINATION; MICROARRAY AB Activated DNA was immobilized in aldehyde-containing polyacrylamide gel for use in manufacturing the MAGIChip (microarrays of gel-immobilized compounds on a chip). First, abasic sites were generated in DNA by partial acidic depurination. Amino groups were then introduced into the abasic sites by reaction with ethylenediamine and reduction of the aldimine bonds formed. It was found that DNA could be fragmented at the site of amino group incorporation or preserved mostly unfragmented. In similar reactions, both amino-DNA and amino-oligonucleotides were attached through their amines to polyacrylamide gel derivatized with aldehyde groups. Single-and double-stranded DNA of 40 to 972 nucleotides or base pairs were immobilized on the gel pads to manufacture a DNA microchip. The microchip was hybridized with fluorescently labeled DNA-specific oligonucleotide probes. This procedure for immobilization of amino compounds was used to manufacture MAGIChips containing both DNA and oligonucleotides. (C) 1998 Academic Press. C1 Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. VA Engelhardt Mol Biol Inst, Joint Human Genome Program, Moscow 117984, Russia. RP Mirzabekov, A (reprint author), Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 26 TC 150 Z9 166 U1 2 U2 14 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD MAY 15 PY 1998 VL 259 IS 1 BP 34 EP 41 DI 10.1006/abio.1998.2620 PG 8 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZR521 UT WOS:000073985900005 PM 9606140 ER PT J AU Jensen, PK Harrata, AK Lee, CS AF Jensen, PK Harrata, AK Lee, CS TI Monitoring protein refolding induced by disulfide formation using capillary isoelectric focusing electrospray ionization mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID PANCREATIC RIBONUCLEASE-A; CONFORMATIONAL-CHANGES; REDUCED RIBONUCLEASE; REGENERATION; KINETICS; ELECTROPHORESIS AB Rapid growth in the biotechnology industry has led to a dramatic increase in attention to the protein folding problem. Understanding protein-folding pathways is essential to the production of biopharmaceuticals since commercial production of recombinant proteins often requires a protein-refolding process for recovery of high yields. Protein folding coupled to the formation of disulfide bonds presents one of the simplest approaches to studying folding intermediates. On-line capillary isoelectric focusing-electrospray ionization mass spectrometry (CIEF-ESIMS) is demonstrated for kinetic studies of disulfide bond-induced protein refolding. Refolding intermediates of bovine pancreatic ribonuclease A, a model system for this study, are blocked at different stages by alkylating free thiols with iodoacetate. The alkylation reaction results in the introduction of charge (-1) and mass (59) differences for each alkylation site, providing the means for predictable separation and direct identification of refolding intermediates using CIEF-ESIMS. Besides the observation of refolding intermediates containing different numbers of disulfide bonds and even mixed disulfides, the two-dimensional resolving power of CIEF-ESIMS allows the determination of conformational heterogeneity among groups of refolding intermediates. C1 Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Iowa State Univ, US DOE, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP Lee, CS (reprint author), Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NR 25 TC 23 Z9 24 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 1998 VL 70 IS 10 BP 2044 EP 2049 DI 10.1021/ac9712963 PG 6 WC Chemistry, Analytical SC Chemistry GA ZN641 UT WOS:000073666700005 PM 9608843 ER PT J AU Hoyt, AE Ricco, AJ Bartholomew, JW Osbourn, GC AF Hoyt, AE Ricco, AJ Bartholomew, JW Osbourn, GC TI SAW sensors for the room-temperature measurement of CO2 and relative humidity SO ANALYTICAL CHEMISTRY LA English DT Article ID ACOUSTIC-WAVE DEVICES; GAS-PERMEABILITY; CARBON-DIOXIDE; POLYIMIDES; PERMSELECTIVITY; CONDUCTIVITY AB A pair of polymer-coated 97-MHz SAW delay lines allows simultaneous determination of the concentrations of CO2 and H2O in the gas phase at room temperature, The SAW response of a 370-nm-thick, CO2-permeable polyimide prepared from hexafluoroisopropylidene diphthtalic anhydride and 2,4,5,6-tetramethylphenylenediamine is rapid and reversible for CO2 concentrations from 0.03 to 97% of 1 atm in a pure nitrogen carrier gas stream, but with significant interference from humidity. A 40-nm-thick layer of the hydrophilic material poly(N-vinylpyrrolidone) (PNVP) responds primarily to humidity; 10-60% relative humidity has been examined for a wide range or accompanying CO2 concentrations, Using visually empirical region-of-influence pattern recognition, the optimum two-sensor pair was selected from several possibilities. The effects of noise and gradual film sensitivity degradation ("aging") upon the accuracy of determining CO2 and H2O concentrations were examined: we find that the polyimide-and Pi-coated SAW device pair allows robust quantitation of H2O over the entire concentration range examined, but robust quantitation of CO2 is possible only at low humidity. C1 Sandia Natl Labs, Dept Vis Sci, Albuquerque, NM 87185 USA. Sandia Natl Labs, Microsensor R&D Dept, Albuquerque, NM 87185 USA. RP Ricco, AJ (reprint author), Sandia Natl Labs, Dept Vis Sci, POB 5800, Albuquerque, NM 87185 USA. EM ajricco@sandia.gov; gcosbou@sandia.gov RI Ricco, Antonio/A-5273-2010 NR 24 TC 44 Z9 48 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 1998 VL 70 IS 10 BP 2137 EP 2145 DI 10.1021/ac971095z PG 9 WC Chemistry, Analytical SC Chemistry GA ZN641 UT WOS:000073666700019 ER PT J AU Chen, QM Bartholomew, JC Campisi, J Acosta, M Reagan, JD Ames, BN AF Chen, QM Bartholomew, JC Campisi, J Acosta, M Reagan, JD Ames, BN TI Molecular analysis of H2O2-induced senescent-like growth arrest in normal human fibroblasts: p53 and Rb control G(1) arrest but not cell replication SO BIOCHEMICAL JOURNAL LA English DT Article ID CYCLIN-DEPENDENT KINASES; OXIDATIVE DNA-DAMAGE; HUMAN PAPILLOMAVIRUS E6; P53-INDEPENDENT PATHWAY; RETINOBLASTOMA PROTEIN; INHIBITOR P21; E7; EXPRESSION; INDUCTION; CHECKPOINTS AB Human diploid fibroblasts lose the capacity to proliferate and enter a state termed replicative senescence after a finite number of cell divisions in culture. When treated with sub-lethal concentrations of H2O2, pre-senescent human fibroblasts enter longterm growth arrest resembling replicative senescence. To understand the molecular basis for the H2O2-induced growth arrest, we determined the cell cycle distribution, levels of p53 tumour suppressor and p21 cyclin-dependent kinase inhibitor proteins, and the status of Rb phosphorylation in H2O2-treated cells. A 2-h pulse of H2O2 arrested the growth of IMR-90 fetal lung fibroblasts for at least 15 days. The arrested cells showed a G(1) DNA content. The level of p53 protein increased 2- to 3-fold within 1.5 h after H2O2 exposure but returned to the control level by 48 h. The induction of p53 protein was dose dependent, beginning at 50-75 mu M and reaching a maximum at 100-250 mu M. The induction of p53 did not appear to correlate with the level of DNA damage as measured by the formation of 8-oxo-2'-deoxyguanosine in DNA. The level of p21 protein increased about 18 h after H2O2 exposure and remained elevated for at least 21 days. During this period, Rb remained underphosphorylated. The induction of p53 by H2O2 was abolished by the iron chelator deferoxamine and the protein synthesis inhibitor cycloheximide. The human papillomavirus protein E6, when introduced into the cells, abolished the induction of p53, reduced the induction of p21 to a minimal level and allowed Rb phosphorylation and entry of the cells into S-phase. The human papillomavirus protein E7 reduced the overall level of Rb and also abolished H2O2-induced G(1) arrest. Inactivating G(1) arrest by E6, E7 or both did not restore the replicative ability of H2O3-treated cells. Thus H2O3-treated cells show a transient elevation of p53, high level of p21, lack of Rb phosphorylation, G(1) arrest and inability to replicate when G(1) arrest is inactivated. C1 Univ Calif Berkeley, Div Biochem & Mol Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Melvin Calvin Lab, Div Struct Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Chen, QM (reprint author), Univ Arizona, Coll Med, Dept Pharmacol, Tucson, AZ 85724 USA. FU NCI NIH HHS [CA39910]; NIA NIH HHS [AG09909]; NIEHS NIH HHS [ES01896] NR 44 TC 294 Z9 307 U1 0 U2 8 PU PORTLAND PRESS PI LONDON PA 59 PORTLAND PLACE, LONDON, ENGLAND W1N 3AJ SN 0264-6021 J9 BIOCHEM J JI Biochem. J. PD MAY 15 PY 1998 VL 332 BP 43 EP 50 PN 1 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZQ576 UT WOS:000073881900006 PM 9576849 ER PT J AU Foster, AL Brown, GE Parks, GA AF Foster, AL Brown, GE Parks, GA TI X-ray absorption fine-structure spectroscopy study of photocatalyzed, heterogeneous As(III) oxidation on kaolin and anatase SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ARSENATE; ADSORPTION; MONTMORILLONITE; SELENIUM; SOILS; ARSENIC(III); MECHANISMS; SPECIATION; INTERFACE; ARSENITE AB We have used X-ray absorption fine-structure spectroscopy (XAFS) to investigate As(III) adsorption on bulk Georgia kaolin (KGa-1b), Wyoming smectite (SWy-2), anatase (TiO2), gibbsite [Al(OH)(3)], and amorphous silica (am-SiO2) with the goal of identifying the oxidants responsible for As(III) oxidation in KGa-1b. After 30 h of reaction, greater than or equal to 30% of the added As(III) was oxidized to As(V) in KGa-1b and anatase experiments, whereas only approximate to 10% of the added As(III) was oxidized in experiments using bulk SWy-2 and gibbsite. As(III) oxidation was negligible in experiments using am-SiO2. The proportion of As(III) oxidized by KGa-1b increased with increasing equilibration time, decreased significantly with increasing pH (up to pH 8), and decreased slightly with increasing ionic strength. Although Mn has been proposed as the potential oxidant of As(III) in KGa-1b, it can account for only approximate to 2% of the As(V) produced under the conditions of our experiments because of its low concentration in this material (3 ppm). Proof that a Ti-containing phase rather than a Mn-containing phase is the primary oxidant of As(III) in KGa-1b is provided by experimental results showing that As(III) oxidation in slurries of KGa-1b and anatase is strongly dependent on both light and the concentration of oxygen, whereas the extent of As(III) oxidation by Mn(IV) is independent of oxygen concentration. The reaction of As(III) with natural or synthetic Ti-containing phases could provide new remediation strategies for arsenic. The high Ti content of the standard reference kaolins KGa-1 and KGa-1b is a result of the unique genesis of this clay deposit and may not be representative of soil kaolins in general. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Foster, AL (reprint author), Stanford Univ, Dept Geol & Environm Sci, Bldg 320,Rm 118, Stanford, CA 94305 USA. EM andrea@pangea.stanford.edu NR 38 TC 54 Z9 56 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 15 PY 1998 VL 32 IS 10 BP 1444 EP 1452 DI 10.1021/es970846b PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZN466 UT WOS:000073648700013 ER PT J AU Whitmore, SA Crawford, J Apostolou, S Eyre, H Baker, E Lower, KM Settasatian, C Goldup, S Seshadri, R Gibson, RA Mathew, CG Cleton-Jansen, AM Savoia, A Pronk, JC Auerbach, AD Doggett, NA Sutherland, GR Callen, DF AF Whitmore, SA Crawford, J Apostolou, S Eyre, H Baker, E Lower, KM Settasatian, C Goldup, S Seshadri, R Gibson, RA Mathew, CG Cleton-Jansen, AM Savoia, A Pronk, JC Auerbach, AD Doggett, NA Sutherland, GR Callen, DF TI Construction of a high-resolution physical and transcription map of chromosome 16q124.3: A region of frequent loss of heterozygosity in sporadic breast cancer SO GENOMICS LA English DT Article ID CARCINOMA IN-SITU; GENE; 16Q; DELETION; 16Q24.3; PISSLRE; CLONING; GROWTH AB A breast cancer tumor suppressor gene has been localized to chromosome 16q24.3 by loss of heterozygosity (LOH) studies of breast tumor DNA, To identify candidate genes for this suppressor function, we have constructed a detailed physical map extending approximately 940 kb from the telomere of the long arm of chromosome 16 that encompasses the minimum LOH interval. This contig consists of a minimum overlapping set of 35 cosmids and a single PAC clone that were aligned by restriction enzyme site mapping. Cosmids were initially identified by screening filters with markers localized to the region by physical mapping using mouse/human somatic cell hybrids, and subsequently cosmid ends were used to complete the contig, A total of seven known genes, including PRSM1, PISSLRE, and the recently cloned Fanconi anemia A (FAA) gene, and potential transcripts from exon-trapping experiments have been located to this contig. A minimum of 14 new transcripts have been identified based on homology of trapped exons with database sequences. This contig and expressed sequence map will form the basis for the identification of the breast cancer tumor suppressor gene in this region. (C) 1998 Academic Press. C1 Womens & Childrens Hosp, Dept Cytogenet & Mol Genet, Ctr Med Genet, N Adelaide, SA 5006, Australia. Fox Chase Canc Ctr, Dept Med Oncol, Philadelphia, PA 19111 USA. Univ S Australia, Dept Haematol & Oncol, Flinders Med Ctr, Bedford Pk, SA, Australia. UMDS, Div Med & Mol Genet, Guys Hosp, London, England. Leiden Univ Hosp, Dept Pathol, NL-2300 RC Leiden, Netherlands. Osped CSS, IRCCS, Serv Genet Med, I-71013 San Giovanni Rotondo, Italy. Free Univ Amsterdam, Dept Human Genet, NL-1081 HV Amsterdam, Netherlands. Rockefeller Univ, Lab Human Genet & Hematol, New York, NY 10021 USA. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM 87544 USA. RP Whitmore, SA (reprint author), Womens & Childrens Hosp, Dept Cytogenet & Mol Genet, Ctr Med Genet, 72 King William Rd, N Adelaide, SA 5006, Australia. EM swhitmor@pulse.mad.adelaide.edu.au RI Sutherland, Grant/D-2606-2012; Callen, David/G-1975-2012; Crawford, Joanna /F-9135-2013; Mathew, Christopher/G-3434-2015; Savoia, Anna/B-6463-2014 OI Crawford, Joanna /0000-0003-0786-6889; Mathew, Christopher/0000-0003-4178-1838; Savoia, Anna/0000-0002-2407-2696 FU NHLBI NIH HHS [HL32987] NR 33 TC 44 Z9 44 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD MAY 15 PY 1998 VL 50 IS 1 BP 1 EP 8 DI 10.1006/geno.1998.5316 PG 8 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA ZU032 UT WOS:000074154400001 PM 9628816 ER PT J AU Christensen, U Olson, P Glatzmaier, GA AF Christensen, U Olson, P Glatzmaier, GA TI A dynamo model interpretation of geomagnetic field structures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTHS INNER-CORE; ROTATION; GEODYNAMO AB We present numerical dynamo models which qualitatively reproduce some structural characteristics of the present-day geomagnetic field. Time-dependent convection in an electrically conducting, rotating spherical shell at Ekman numbers 1-3 x 10(-4) generates dipole-dominated magnetic fields, which exhibit distinct bundles of strong radial flux at high latitudes, low flux over the poles, and paired spots of reversed flux near the equator, suggestive of the geomagnetic field pattern at the core-mantle boundary. In our model these structures result from high magnetic Reynolds number, helical convection in columns parallel to the spin axis and rising plumes near the poles. C1 Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. Univ Calif Los Alamos Natl Lab, Inst Geophys & Planetary Phys, Los Alamos, NM 87545 USA. Univ Gottingen, Inst Geophys, D-37075 Gottingen, Germany. RP Christensen, U (reprint author), Univ Gottingen, Inst Geophys, Landstr 180, D-37075 Gottingen, Germany. EM urc@willi.uni-geophys.gwdg.de; olson@gibbs.eps.jhu.edu; gag@lanl.gov NR 16 TC 75 Z9 75 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1998 VL 25 IS 10 BP 1565 EP 1568 DI 10.1029/98GL00911 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZN248 UT WOS:000073626900007 ER PT J AU Guyer, RA McCall, KR Van Den Abeele, K AF Guyer, RA McCall, KR Van Den Abeele, K TI Slow elastic dynamics in a resonant bar of rock SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Recent resonant bar experiments on Berea sandstone show that nonlinear excitation of the sample excites a slow dynamics with a time scale many orders of magnitude longer than the excitation period, 2 pi/omega. That is, a nonlinear resonant frequency decays to the linear resonant frequency long after the high amplitude drive has been turned off. We postulate a phenomenological theory of slow nonlinear dynamics in the context of a resonant bar experiment. The normalized elastic modulus of the resonant bar is allowed to be nonlinear and time dependent. The nonlinear terms are derived from a model of elasticity in rocks that includes anharmonic and hysteretic contributions. We use this theory to explain the experimental results. We find an explanation for the slow relaxation of the experimental resonant frequency using an anharmonic contribution to the modulus that responds instantaneously to a disturbance, and a contribution derived from elastic hysteresis that displays slow dynamics. We suggest an acoustic NMR-type experiment to explore slow nonlinear dynamics. C1 Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. RP Guyer, RA (reprint author), Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. NR 12 TC 44 Z9 45 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1998 VL 25 IS 10 BP 1585 EP 1588 DI 10.1029/98GL51231 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZN248 UT WOS:000073626900012 ER PT J AU Bigoli, F Deplano, P Mercuri, ML Pellinghelli, MA Pintus, G Trogu, EF Zonnedda, G Wang, HH Williams, JM AF Bigoli, F Deplano, P Mercuri, ML Pellinghelli, MA Pintus, G Trogu, EF Zonnedda, G Wang, HH Williams, JM TI Novel oxidation and reduction products of the neutral nickel-dithiolene [Ni(Pr(2)(i)timdt)(2)] (Pr(2)(i)timdt is the monoanion of 1,3-diisopropylimidazolidine-2,4,5-trithione) SO INORGANICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT XXXIII International Conference on Coordination Chemistry CY AUG 30-SEP 04, 1998 CL FLORENCE, ITALY DE crystal structures; nickel complexes; dithiolene complexes ID CORRELATED CHEMICAL-SYSTEMS; NEAR-IR ABSORPTION; MOLECULAR-STRUCTURE; THERMODYNAMIC PARAMETERS; CRYSTAL-STRUCTURE; SOLID-STATE; COMPLEXES; ET4TODIT; 4,5,6,7-TETRATHIOCINO<1,2-B-3,4-B'>DIIMIDAZOLYL-1,3,8,10-TETRAETHYL-2,9- DITHION.; SPECTRA AB [Ni(Pr(2)(i)timdt)(2)] (1) (Pr(2)(i)timdt is the monoreduced form of 1,3-diisopropylimidazolidine-2,4,5-trithione), which belongs to a new class of nickel-dithiolenes showing remarkably high absorption in the near-IR (lambda approximate to 1000 nm), is reduced by use of 1,4-phenylenediamine to the monoanion [Ni(Pr(2)(i)timdt)(2)](-1). This is isolated in the solid state as Bu4N[Ni(Pr(2)(i)timdt)(2)] (2), and exhibits in CH3CN solution the near-IR absorption at lambda = 1384 nm. By reaction of 1 with IBr (1:4 molar ratio between reagents in CHCl3-CH3CN mixtures), a solid, whose analytical and spectral results suggest it to be an adduct of 4,5,9,10-tetrathiocino[1,2-b:5,6-b']diimidazolyl-1,3,6,8-tetraisopropane-2,7-dithione with I-2 and IBr (3), is isolated. The same reaction performed with a large excess of IBr (1:60 molar ratio) gives on standing (three weeks) orange-red crystals (4) formed by the dication 4,5,9,10-tetrathiocino[1,2-b:5,6-b']diimidazolium-1,3,6,8-tetraisopropane-2,7-diiodo containing IBr2- counterions. Spectroscopic and X-ray diffraction studies of 2 (monoclinic, space group P2(1)/c, a = 18.396(5), b = 13.553(6), c = 17.582(5) Angstrom, beta = 96.59(2)degrees, Z = 4) and 4 (monoclinic, space group P2(1)/c, a = 9.304(7), b = 8.202(7), c = 23.289(5) Angstrom, beta = 100.93(2)degrees, Z = 2), are given. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Univ Cagliari, Dipartimento Chim & Tecnol Inorgan & Met Organ, I-09124 Cagliari, Italy. CNR, Ctr Studio Strutturist Diffrattometr, CNR, Dipartimento Chim Gen & Inorgan Chim Analit Chim, I-43100 Parma, Italy. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. RP Deplano, P (reprint author), Univ Cagliari, Dipartimento Chim & Tecnol Inorgan & Met Organ, Via Osped 72, I-09124 Cagliari, Italy. NR 31 TC 33 Z9 34 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD MAY 15 PY 1998 VL 273 IS 1-2 BP 175 EP 183 DI 10.1016/S0020-1693(97)06007-6 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA ZP204 UT WOS:000073728200024 ER PT J AU Falkenstein, Z AF Falkenstein, Z TI Frequency dependence of photoresist ashing with dielectric barrier discharges in oxygen SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID WAFER TEMPERATURE; PLASMAS; POLYMERS; DAMAGE; MECHANISMS; MODEL; OXIDE AB This article presents results of the frequency dependence on surface etching of a Novolak-type polymer (Shipley, SPR2) on Si wafers using dielectric barrier discharges in oxygen near atmospheric pressures and room temperature. The etching depth of the photoresist is measured by mechanical profilometry as a function of the applied sinusoidal frequency (1-40 kHz) at different oxygen pressures (250-750 mbar) and gap distances (1-20 mm), along with the energy density that is supplied to the sample surface and into the gas volume, respectively. This approach enables one to generate figures of merit for the etching rates, allowing comparison with conventional plasma surface treatments, as etching rate per power density coupled onto the sample surface (nm min(-1) W-1 cm(2)), or coupled into the gas volume (nm min(-1) W-1 cm(3)). For all gap spacings and gas pressures both power-density specific etch rates increase with increased applied frequencies, and show an optimal gap distance and gas pressure. The surface of the etched photoresist is characterized by scanning electron microscopy,showing decreasing material damage with increasing frequency. The results obtained in this work suggest dielectric barrier discharges at high frequencies (>10's kHz) as an efficient, alternative plasma source for general surface processing, as they can provide nonthermal gas discharges near atmospheric pressures and thereby eliminate the need for costly vacuum systems without major damage of the plasma-treated surface. (C) 1998 American Institute of Physics. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Falkenstein, Z (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM falkenstein@lanl.gov NR 35 TC 17 Z9 19 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5095 EP 5101 DI 10.1063/1.367402 PG 7 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600013 ER PT J AU Hebner, GA Fleddermann, CB AF Hebner, GA Fleddermann, CB TI Relative atomic chlorine density in inductively coupled plasmas containing chlorine and boron trichloride SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRON-CYCLOTRON-RESONANCE; CL AB Two photon allowed laser induced fluorescence has been used to measure the relative atomic chlorine density in inductively driven radio frequency discharges containing mixtures of chlorine, boron trichloride, argon and nitrogen. In contrast with previous measurements in pure chlorine discharges, the atomic chlorine density increased with rf power in pure BCl3 discharges. In mixtures of Cl-2 and BCl3, the Cl density was constant with rf power and increased with pressure, similar to pure Cl-2 discharges. In addition, the Cl density varied linearly with Cl-2/BCl3 ratio, and was a factor of three higher in pure Cl-2 than in pure BCl3. The addition of argon or nitrogen to BCl3/Cl-2 mixtures had no effect on the relative Cl density. Finally, measurements of the Cl density as a function of spatial location showed that the Cl density was uniform in the discharge region. Several gas phase chemical mechanisms in Cl-2/BCl3 plasmas are hypothesized based on the atomic chlorine measurements presented in this work with previous measurements of other gas phase plasma species in this reactor geometry. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Elect & Comp Engn, Albuquerque, NM 87131 USA. RP Hebner, GA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM gahebne@sandia.gov NR 26 TC 17 Z9 17 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5102 EP 5107 DI 10.1063/1.367327 PG 6 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600014 ER PT J AU Gardner, JA Edwards, A Rao, MV Papanicolaou, N Kelner, G Holland, OW Capano, MA Ghezzo, M Kretchmer, J AF Gardner, JA Edwards, A Rao, MV Papanicolaou, N Kelner, G Holland, OW Capano, MA Ghezzo, M Kretchmer, J TI Material and n-p junction properties of N-, P-, and N/P-implanted SiC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TEMPERATURE AB Elevated temperature (ET) multiple energy N, P, and N/P implantations were performed into p-type 6H-SiC epitaxial layers. For comparison, room temperature (RT) N and P implantations were also performed. In the N/P coimplanted material a sheet resistance of 2.1X10(2) Ohm/square was measured, which is lower compared to the values measured in N or P implanted material of the same net donor dose. The RT P implantation resulted in heavy lattice damage and consequently low P electrical activation, even after 1600 degrees C annealing. After annealing the Rutherford backscattering yield either coincided or came close to the virgin level for ET implantations and RT N implantation, whereas for RT P implantation the yield was high, indicating the presence of high residual damage. Vertical n-p junction diodes were made by selective area ET N, P, and N/P implantations and RT N and P implantations using a 2.5 mu m thick SiO2 layer as an implant mask. The diodes were characterized by capacitance-voltage and variable temperature current-voltage measurements. (C) 1998 American Institute of Physics. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. USN, Res Lab, Washington, DC 20375 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. AFRL, MLPO, Wright Patterson AFB, OH 45433 USA. GE, Corp Res & Dev, Schenectady, NY 12301 USA. RP Gardner, JA (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. NR 14 TC 41 Z9 41 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5118 EP 5124 DI 10.1063/1.367329 PG 7 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600016 ER PT J AU Grigull, S Jacob, W Henke, D Spaeth, C Summchen, L Sigle, W AF Grigull, S Jacob, W Henke, D Spaeth, C Summchen, L Sigle, W TI Transport and structural modification during nitrogen implantation of hard amorphous carbon films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ION-BEAM DEPOSITION; CUBIC BORON-NITRIDE; A-C-H; THIN-FILMS; COMPRESSIVE STRESS; GLASSY-CARBON; GRAPHITE; SPECTROSCOPY; SILICON; LAYERS AB Hard amorphous carbon (ta-C) films were implanted with 20 keV N+ ions with different fluences up to 6 X 10(17)/cm(2) at different substrate temperatures. The nitrogen content of the films was monitored in situ using elastic recoil detection analysis, A characteristic temperature dependence is observed for the maximum achievable [N]/[C] composition ratio, with a drop of the saturation level from the room-temperature value of 0.35 to 0.17-0.12 above 150 degrees C. It is shown that the higher nitrogen retention at room temperature is correlated with the formation of N-2-containing gas bubbles which are not present in samples implanted with high fluences at elevated temperatures. From residual-gas analyses it is found that nitrogen is reemitted from the films mainly as N-2 when saturation occurs. Double-implantation experiments with spatially separated N-14 and N-15 implanted regions, respectively, indicate that the N-N molecule recombination observed at large implantation fluences occurs inside the films and not at the surface. Significant changes of the microstructure of the films are found with increasing implantation fluences. Inside the implanted near-surface region of several 10 nm thickness the density of the material decreases from,3.0 to about 1.7 g/cm(-3). Graphitic clusters are identified in samples implanted up to saturation at 400 degrees C, using cross-section transmission electron microscopy. A basic approach to modeling the nitrogen saturation and release at large fluences is presented. Both nitrogen release and structural modification processes are interpreted as a tendency towards thermodynamic equilibrium which may constitute a strong driving force against the synthesis of nitrogen-rich hard C:N materials, compared to other nitride phases. (C) 1998 American Institute of Physics. C1 Forschungszentrum Rossendorf EV, Inst Ionenstrahlphys & Materialforsch, D-01314 Dresden, Germany. EURATOM, Max Planck Inst Plasmaphys, D-85748 Garching, Germany. Tech Univ Chemnitz, Inst Phys, D-09107 Chemnitz, Germany. Tech Univ Dresden, Inst Analyt Chem, D-01062 Dresden, Germany. Max Planck Inst Met Res, D-70569 Stuttgart, Germany. RP Los Alamos Natl Lab, Mat Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. EM grigull@lanl.gov OI Jacob, Wolfgang/0000-0003-3504-142X NR 71 TC 22 Z9 22 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5185 EP 5194 DI 10.1063/1.367338 PG 10 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600025 ER PT J AU McDonald, J Clem, JR Oates, DE AF McDonald, J Clem, JR Oates, DE TI Critical-state model for intermodulation distortion in a superconducting microwave resonator SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; YBA2CU3O7-X; IMPEDANCE; LOSSES; FIELD; NBN AB A model is presented for the treatment of intermodulation distortion in a superconducting transmission line caused by vortex penetration and hysteresis. An analytical framework is developed, and numerical results are presented for center conductors of both circular and rectangular thin-film cross section. (C) 1998 American Institute of Physics. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. MIT, Lincoln Lab, Lexington, MA 02173 USA. RP McDonald, J (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 19 TC 12 Z9 12 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5307 EP 5312 DI 10.1063/1.367356 PG 6 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600043 ER PT J AU Cheong, HM Mascarenhas, A Ahrenkiel, SP Jones, KM Geisz, JF Olson, JM AF Cheong, HM Mascarenhas, A Ahrenkiel, SP Jones, KM Geisz, JF Olson, JM TI Effect of microstructure on excitonic luminescence of spontaneously ordered Ga0.52In0.48P alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SUBSTRATE AB We compare the results of low-temperature (4.2 K) microphotoluminescence (PL) measurements on cleaved edges of spontaneously ordered GaInP2 alloy samples with the results of cross-section transmission electron microscopy (TEM). The TEM dark-field images show that the size of ordered domains grows as the deposition progresses. The excitonic luminescence peak in the micro-FL spectra of GaInP2 is stronger near the surface of the thin film than near the substrate. From these results, we conclude that there is a direct correlation between the domain size or alternatively, the density of domain boundaries, and the relative strength of the excitonic peak. (C) 1998 American Institute of Physics. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Cheong, HM (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Cheong, Hyeonsik/D-7424-2012 OI Cheong, Hyeonsik/0000-0002-2347-4044 NR 7 TC 18 Z9 18 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5418 EP 5420 DI 10.1063/1.367371 PG 3 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600060 ER PT J AU Joshi, RP Wood, RF AF Joshi, RP Wood, RF TI Simulations of charge transport across a grain boundary in n-silicon bicrystals SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID EFFECTIVE BARRIER HEIGHTS; MIXED-PHASE CONTACTS; MOLECULAR-DYNAMICS; CARRIER TRANSPORT; SCHOTTKY CONTACTS; SEMICONDUCTORS; COPPER; FLUCTUATIONS; SPECTROSCOPY; SEGREGATION AB Electron transport in Si low-angle bicrystals is analyzed by a novel Monte Carlo-molecular dynamics simulation scheme. The effect of discrete charges at the grain boundaries are studied and compared to results from one-dimensional treatments. The average grain boundary charge density strongly influences transport, and a field-dependent threshold effect is predicted. Details of the internal charge arrangement are shown to be relatively important at low fields and/or high grain boundary charge densities. (C) 1998 American Institute of Physics. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. RP Joshi, RP (reprint author), Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. NR 27 TC 2 Z9 2 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5543 EP 5545 DI 10.1063/1.367385 PG 3 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600080 ER PT J AU Shield, JE Branagan, DJ Li, CP McCallum, RW AF Shield, JE Branagan, DJ Li, CP McCallum, RW TI The effect of grain size on magnetic properties in Sm2Fe17Nx SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTERMETALLIC COMPOUNDS AB The microstructures of melt spun Sm11Fe89 and (Sm11Fe89)(94)Ti3C3 have been investigated under different solidification conditions. The magnetic properties of the nitrided materials have been related to the observed microstructures. Melt spinning of the Sm11Fe89 alloys resulted in grain sizes at or above the single domain limit. The addition of Ti and C resulted in an order of magnitude refinement in the microstructural scale. The magnetic properties of the samples with grain sizes below the single domain limit decreased with decreasing grain size due to increased intergranular exchange coupling. (C) 1998 American Institute of Physics. C1 Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Ames Lab, Ames, IA 50011 USA. RP Shield, JE (reprint author), Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA. NR 9 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5564 EP 5566 DI 10.1063/1.367391 PG 3 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600087 ER PT J AU Devine, RAB Warren, WL Karna, S AF Devine, RAB Warren, WL Karna, S TI Comment on "A model of hole trapping in SiO2 films on silicon" [J. Appl. Phys. 81, 6822 (1997)] SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SI/SIO2/SI STRUCTURES; TEMPERATURE; OXYGEN AB Recent measurements of oxygen-vacancy creation in Si/SiO2/Si structures during high temperature annealing which suggest an activation energy of 1.5 eV for the process have been interpreted in terms of a simple thermodynamic model. We demonstrate that this model is inconsistent with thermochemical calculations which indicate that the energy for this process is 4.5 eV [K. P. Huber and G. Hertz, Molecular Structure and Molecular Structure IV, Constants of Diatomic Molecules (Van Nostrand Reinhold, New York, 1979), p. 490]. Another process involving thermally induced oxygen out-diffusion at the SiO2/Si interface has an effective activation energy for oxygen-vacancy creation similar to 2.0 eV, this is more consistent with the experimental data. (C) 1998 American Institute of Physics. C1 France Telecom, Ctr Natl Etud Telecommun, F-38243 Meylan, France. Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87185 USA. USAF, Phillips Lab, Albuquerque, NM 87117 USA. RP Devine, RAB (reprint author), France Telecom, Ctr Natl Etud Telecommun, BP 98, F-38243 Meylan, France. NR 13 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5591 EP 5592 DI 10.1063/1.367498 PG 2 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600096 ER PT J AU Keightley, JA Sanders, D Todaro, TR Pastuszyn, A Fee, JA AF Keightley, JA Sanders, D Todaro, TR Pastuszyn, A Fee, JA TI Cloning and expression in Escherichia coli of the cytochrome c(552) gene from Thermus thermophilus HB8 - Evidence for genetic linkage to an ATP-binding cassette protein and initial characterization of the cycA gene products SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID C-TYPE CYTOCHROMES; RHODOBACTER-SPHAEROIDES CYTOCHROME-C2; AMINO-ACID SEQUENCE; NUCLEOTIDE-SEQUENCE; PARACOCCUS-DENITRIFICANS; HYDROGENOBACTER-THERMOPHILUS; BRADYRHIZOBIUM-JAPONICUM; RESPIRATORY PROTEINS; MOLECULAR-CLONING; EUGLENA-GRACILIS AB We report sequence of Thermus thermophilus HB8 DNA containing the gene (cycA) for cytochrome c(552) and a gene (cycB) encoding a protein homologous with one subunit of an ATP-binding cassette transporter. The cycA gene encodes a 17-residue N-terminal signal peptide with following amino acid sequence identical to that reported by (Titani, K., Ericsson, L. H., Hon-nami, K., and Miyazawa, T. (1985) Biochem. Biophys, Res. Commun. 128, 781-787), A modified cycA was placed under control of the T7 promoter and expressed in Escherichia coli, Protein identical to that predicted from the gene sequence was found in two heme C-containing fractions. Fraction rC(552), characterized by an alpha-band at 552 nm, contains similar to 60-70% of a protein highly similar to native cytochrome c(552) and similar to 30-40% of a protein that contains a modified heme, Cytochrome rC(552) is monomeric and is an excellent substrate for cytochrome ba(3). Cytochrome rC(557) is characterized by an alpha-band at 557 nm, contains similar to 90% heme C and similar to 10% of non-C heme, exists primarily as a homodimer, and is essentially inactive as a substrate for cytochrome ba(3), We suggest that rC(557) is a "conformational isomer" of rC(552) having non-native, axial ligands to the heme iron and an "incorrect" protein fold that is stabilized by homodimer formation. C1 Univ Calif San Diego, Dept Biol, La Jolla, CA 92093 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Biochem & Mol Biol, Albuquerque, NM 87131 USA. Univ Calif San Diego, Prot Chem Lab, La Jolla, CA 92093 USA. RP Fee, JA (reprint author), Univ Calif San Diego, Dept Biol, 9500 Gilman Dr, La Jolla, CA 92093 USA. EM jfee@ucsd.edu FU NCRR NIH HHS [RR07273]; NIGMS NIH HHS [GM35342] NR 83 TC 32 Z9 32 U1 1 U2 3 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAY 15 PY 1998 VL 273 IS 20 BP 12006 EP 12016 DI 10.1074/jbc.273.20.12006 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZN277 UT WOS:000073629800006 PM 9575141 ER PT J AU Stec, DF Maxwell, RS Cho, H AF Stec, DF Maxwell, RS Cho, H TI Protonated sites on sulfate-promoted zirconium oxide catalysts: A Fourier transform IR, thermal analysis, and solid state H-1 NMR study SO JOURNAL OF CATALYSIS LA English DT Article ID NORMAL-BUTANE ISOMERIZATION; BROAD-LINE H-1-NMR; ACID SITES; SUPERACID CATALYST; MAGNETIC-RESONANCE; SILICA SURFACE; METAL-OXIDES; TEMPERATURE; WATER; ADSORPTION AB A series of sulfate-promoted ZrO2 solid acid catalysts samples were prepared, each sample differing only in the pH of the sulfuric acid soaking step of the synthesis procedure. Fourier-transform infrared (FTIR) spectra and thermal weight-loss measurements (as measured by thermal gravimetric analysis (TGA)) indicate that the pH of the sulfuric acid soaking solution influences the number of surface proton sites. The activity of sulfate-promoted ZrO2 in catalyzing the isomerization of n-butane to iso-butane at 220 degrees C and the surface area of the calcined catalyst are also found to depend on the soaking solution pH, with maximum surface areas and activities observed between pH 6 and pH 9. Proton nuclear magnetic resonance (NMR) chemical shifts measured using combined rotation and multiple pulse spectroscopy indicate that the sulfating step produces proton species that are more acidic than proton sites on the nonsulfated support. The proton NMR spectra of these samples consist of at least two overlapped, but distinct, resonances that can be separated on the basis of a large disparity in spin-lattice (T-1) relaxation times. By comparing the experimental spectra with a series of simulated spectra, the long T-1 component has been assigned to a discrete three-or four-proton site that includes one water molecule, and the short T-1 component to an ill-defined cluster of protons. Variable-temperature NMR lineshape data also suggest that the protons are in rapid motion on the sulfate-promoted zirconium oxide surface. (C) 1998 Academic Press. C1 Pacific Nw Natl lab, Environm Mol Sci Lab MS K898, Richland, WA 99352 USA. RP Stec, DF (reprint author), Stanford Univ, Dept Chem Engn, Stanford, CA 94305 USA. NR 58 TC 4 Z9 4 U1 2 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1998 VL 176 IS 1 BP 14 EP 24 DI 10.1006/jcat.1998.2000 PG 11 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA ZR656 UT WOS:000074000600002 ER PT J AU Yoon, CH Yang, MX Somorjai, GA AF Yoon, CH Yang, MX Somorjai, GA TI Reactions of 1-butene and cis-2-butene on platinum surfaces: Structure sensitivity of cis-2-butene isomerization SO JOURNAL OF CATALYSIS LA English DT Article ID HYDROGENATION; PT(111) AB The hydrogenation and isomerization of 1-butene and cis-2-butene molecules are studied on platinum foil and single crystal (111), (100), and the stepped (755) surfaces at 300-350 K. In the presence of hydrogen, 1-butene and cis-2-butene are hydrogenated to butane. In addition, 1-butene is isomerized to cis-and trans-2-butenes, while cis-2-butene is converted to trans-2-butene. With a hydrogen pressure between 7 and 500 Torr, and a butene pressure of 3.5-70 Torr, both butene hydrogenation and isomerization rates exhibit a near-first-order dependence on the hydrogen pressure and a zero-order dependence on the hydrocarbon pressures. For both 1-butene and cis-2-butene molecules, the hydrogenation rates are insensitive to surface structures. The isomerization rate, however, is doubled for cis-2-butene molecules on the stepped platinum surface (Pt(755)). (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. NR 22 TC 27 Z9 27 U1 0 U2 8 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1998 VL 176 IS 1 BP 35 EP 41 DI 10.1006/jcat.1998.1990 PG 7 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA ZR656 UT WOS:000074000600004 ER PT J AU Su, SC Carstens, JN Bell, AT AF Su, SC Carstens, JN Bell, AT TI A study of the dynamics of Pd oxidation and PdO reduction by H-2 and CH4 SO JOURNAL OF CATALYSIS LA English DT Article ID PALLADIUM OXIDE; PD(111) SURFACE; OXYGEN; METHANE; CATALYSTS; PD(100); SPECTROSCOPY; COMBUSTION; DESORPTION; ADSORPTION AB Palladium is one of the most active catalysts for the catalytic combustion of methane. Since Pd is oxidized during methane combustion to PdO and PdO is required for high activity, it is of interest to understand the dynamics of Pd oxidation and the structure of the oxide formed as well as the dynamics of PdO reduction by H-2 and CH4. In the present study isothermal and temperature-programmed oxidation and reduction were used to probe the dynamics of the oxidation and reduction of zirconia-supported Pd. During uptake in oxygen, a monolayer of oxide is generated immediately, and upon further oxidation, the oxide forms a shell around a core of metal with thicknesses that increase with the oxidation temperature. The initial oxide is amorphous and subsequently transforms to crystalline PdO. The dynamics of Pd oxidation suggest that oxidation follows the Cabrera-Mott theory. Reduction of PdO by H-2 occurs in a shellwise manner, consistent with a shrinking core mechanism, while reduction in CH4 occurs via an autocatalytic, nucleation mechanism. In the latter case, small particles of Pd must first be formed on which CH4 can dissociate. The fragments (H and CHx (x = 3-1)) diffuse to the metal-oxide boundary where reduction of the oxide occurs. Consistent with this picture, the kinetics of PdO reduction are first order in Pd initially, but then they become zero Order in Pd. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem Engn, Berkeley, CA 94720 USA. RP Su, SC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 38 TC 159 Z9 162 U1 2 U2 42 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1998 VL 176 IS 1 BP 125 EP 135 DI 10.1006/jcat.1998.2028 PG 11 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA ZR656 UT WOS:000074000600014 ER PT J AU Carstens, JN Su, SC Bell, AT AF Carstens, JN Su, SC Bell, AT TI Factors affecting the catalytic activity of Pd/ZrO2 for the combustion of methane SO JOURNAL OF CATALYSIS LA English DT Article ID SUPPORTED PALLADIUM CATALYSTS; OXIDATION; KINETICS AB The catalytic combustion of CH4 has been investigated over Pd/ZrO2 with the aim of identifying how the state of oxidation of the Pd affects the catalytic activity, particularly at low temperatures. It is found that fully reduced Pd is inactive and that the activity increases at 533 K until a plateau in activity is achieved when 6-7 ML of PdO have formed over the surface of the Pd crystallites. The maximum activity is identical to that for fully oxidized Pd. Examination of the PdO formed under reaction conditions and during oxidation in O-2 at 533 K reveals some differences. Temperature-programmed reduction in CH4 and Raman spectroscopy demonstrate that the oxide formed under reaction conditions is largely crystalline PdO, whereas the oxide formed in O-2 is a mixture of amorphous and crystalline PdO. The crystalline form of PdO is found to reduce more readily than the amorphous form. It is observed that the low-temperature CH4 combustion activity of PdO can be enhanced by producing a small amount of metallic Pd on the surface of PdO. The metallic Pd is more effective than PdO for the dissociative adsorption of CH4. It is hypothesized that the products of CH4 adsorption on Pd, H-s and CHx,s (x = 3-1.), rapidly diffuse to the Pd/PdO interface and then reduce the PdO to Pd. The effects of metallic Pd cannot be sustained, though, under steady-state conditions, because the metallic Pd is oxidized back to PdO. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Carstens, JN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 13 TC 157 Z9 162 U1 1 U2 49 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1998 VL 176 IS 1 BP 136 EP 142 DI 10.1006/jcat.1998.2029 PG 7 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA ZR656 UT WOS:000074000600015 ER PT J AU Chen, YJ Stimson, S Fenn, PT Ng, CY Li, WK Ma, NL AF Chen, YJ Stimson, S Fenn, PT Ng, CY Li, WK Ma, NL TI A study of the dissociation of CH3CH2SH+ by collisional activation: Evidence of nonstatistical behavior SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOIONIZATION MASS-SPECTROMETRY; TOTAL CROSS-SECTIONS; CHARGE-TRANSFER; CH3S; IONIZATION; CH2SH AB The absolute total cross sections for CH3CH2+, C2H4+, C2H3+, CH3+, CH2SH+(CH3S+), CH2S+(HCSH+), CHS+(CSH+), and H2S+ produced by the collision-induced dissociation (CID) reaction of CH3CH2SH++Ar have been measured in the center-of-mass collision energy (E-c.m.) range of 1-42 eV. Using the charge transfer probing technique, we found that the mass 47 product ions have overwhelmingly the CH2SH+ structure. The onsets for CH3CH2+, C2H4+, C2H3+, CH2SH+, H2S+, and CH3+ are consistent with their corresponding thermochemical thresholds. The formation of the higher energy channels CH3CH2+ + SH and CH3+CH2SH+, which involve the C-S and C-C bond scissions, are found to dominate in the entire E-c.m. range. The lower energy channel corresponding to the formation of CH3CHSH++H is not found. The strong preference observed for the formation of the higher energy channels is in accord with the conclusion obtained in the recent CID study of CH3SH+, providing evidence that the CID of CH3CH2SH+ is also nonstatistical. The high yields of CH3CH2++SH and CH2SH++CH3 are attributed to the more efficient translational to vibrational energy transfer for the low frequencies C-S and C-C stretching modes than for the high frequencies C-H and S-H stretching modes, along with the weak couplings between these low and high frequencies vibrational modes of CH3CH2SH+. The relative abundances of product ions formed by the single-photon ionization of CH3CH2SH were also measured for comparison with the CID results. The CH3CHSH++H channel is observed in the photoionization of CH3CH2SH. Similar to the finding in the photoionization of CH3SH, the relative abundances of fragment ions formed in the photoionization of CH3CH2SH are in qualitative accord with statistical predictions. To rationalize the dissociation mechanisms of CH3CH2SH+, we have also performed ab initio calculations to locate the possible transition structures for the observed dissociation channels. (C) 1998 American Institute of Physics. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Chinese Univ Hong Kong, Dept Chem, Shatin, Peoples R China. Hong Kong Polytech Univ, Dept Appl Biol & Chem Technol, Hung Ham, Peoples R China. RP Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. EM CYNG@AMESLAB.GOV RI Chen, Yu-Ju/E-9481-2015 NR 31 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1998 VL 108 IS 19 BP 8020 EP 8028 DI 10.1063/1.476241 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZM675 UT WOS:000073564600012 ER PT J AU Zumbusch, A Schnockel, H AF Zumbusch, A Schnockel, H TI Raman and IR spectroscopy of (GeO)(n), with n=1,2,3,4, isolated in solid argon SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INFRARED SPECTRA; MATRIX ISOLATION; GE2O2; GEO AB Raman and IR spectroscopy of GeOn, with n=1,2,3,4, isolated in solid Ar were used for the elucidation of the corresponding molecular structures. The experiments were complemented by extensive ab initio calculations at different theoretical levels, in the case of Ge2O2 additionally by normal-coordinate analysis. The assignment of a planar, cyclic D-2h symmetric structure to Ge2O2, made formerly on the basis of IR spectroscopic investigations, was confirmed. It was possible to determine all vibrational frequencies of the molecule. The IR and Raman spectra of Ge3O3 allow for the unambiguous assignment of a highly symmetric D-3h ring structure for this molecule, as it has been proposed by other authors. In contrast we find that the previously assumed ring structure for Ge4O4 is incompatible with the measured IR and Raman spectra, as well as with the results of ab initio calculations. Instead a heterocubanelike structure, that is found for the heavier homologus molecules of Sn and Pb, is adopted in this case. (C) 1998 American Institute of Physics. C1 Univ Karlsruhe TH, Inst Anorgan Chem, D-76128 Karlsruhe, Germany. RP Zumbusch, A (reprint author), Pacific NW Lab, MS K8-88,POB 999, Richland, WA 99352 USA. NR 25 TC 32 Z9 34 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1998 VL 108 IS 19 BP 8092 EP 8100 DI 10.1063/1.476248 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZM675 UT WOS:000073564600020 ER PT J AU Wang, JG Zhang, LC Chen, GL Ye, HQ AF Wang, JG Zhang, LC Chen, GL Ye, HQ TI Stress-induced phase transformations in a hot-deformed two-phase (alpha(2)+gamma) TiAl alloy SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID TRANSMISSION ELECTRON-MICROSCOPY; GAMMA-TITANIUM ALUMINIDES; INTERFACIAL BOUNDARIES; INTERMETALLIC ALLOYS; TI-45AL-10NB ALLOY; BASE ALLOYS; DEFORMATION AB Stress-induced gamma --> alpha(2), alpha(2) --> gamma and gamma --> 9R phase transformations in a hot-deformed Ti-45 at % Al-10 at% Nb alloy have been investigated using high-resolution transmission electron microscopy. The gamma --> alpha(2) phase transformation is an interface-related process. The interfacial superdislocations emitted from the misoriented semicoherent alpha(2)-gamma interface react with each other or with the moving dislocations in the gamma phase, resulting in the formation of the at phase. The nucleation of the alpha(2) --> gamma phase transformation takes place either at the alpha(2)-gamma interfaces or at the stacking faults on the basal plane of alpha(2) phase, and the growth of gamma plate is accomplished by the moving of a/6[1 0 (1) over bar 0] Shockley partials on alternate basal plane (0 0 0 1 )(alpha 2). The 9R structure was usually found to form at incoherent twin or pseudotwin boundaries. During deformation the interfacial Shockley partial dislocations of these incoherent twin and pseudotwin boundaries may glide on (1 1 1), planes into the matrix, resulting in the formation of 9R structure. The interfaces (including alpha(2)-gamma and gamma-gamma interfaces) as well as the crystallographic orientation relationship between the as-received or stress-induced alpha(2), gamma and 9R phase have been analysed. The mechanisms for the stress-induced gamma --> alpha(2), alpha(2) --> gamma and gamma --> 9R phase transformations were also discussed. (C) 1998 Chapman & Hall. C1 Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China. Acad Sinica, Inst Met Res, Atom Imaging Solids Lab, Shenyang 110015, Peoples R China. RP Wang, JG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-370, Livermore, CA 94551 USA. NR 27 TC 3 Z9 4 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAY 15 PY 1998 VL 33 IS 10 BP 2563 EP 2571 DI 10.1023/A:1004397001175 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 149DT UT WOS:000077590400009 ER PT J AU Gibson, JK AF Gibson, JK TI Gas-phase reactions of Tc+, Re+, Mo+ and Cu+ with alkenes SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE technetium; rhenium; molybdenum; copper; gas phase reactions; mass spectrometry; alkenes; olefins ID ORGANOMETALLIC CHEMISTRY; LASER-ABLATION; MOLECULAR-STRUCTURE; CLUSTER IONS; OXIDE; TECHNETIUM; HYDROCARBONS; ACTIVATION; COMPLEXES; ENERGIES AB Organometallic complex ions, denoted as M+-L, where M = Tc, Re, Mo or Cu and L = CcHh, were produced by reacting laser-ablated M+ with alkenes (R = ethene, C2H4; propene, C3H6; cis-2-butene, C4H8; cyclohexene, C6H10 and 1,5-cyclooctadiene, C8H12). The compositions and abundances of the M+-L were determined by time-of-flight mass spectrometry. A primary goal was to elucidate gas-phase organotechnetium chemistry and differentiate the behaviors of Re+ and Mo+ from that of Tc+. The ion pairs, Tc+ + Re+ and Tc+ + Mo+, were coablated to provide direct comparisons of reactivities; these M+ were ablated from solid MOx in a copper matrix, which generated Cu+, whose reactivity was also evaluated. For Tc+, Re+ and Mo+, H-2-loss from the alkene was the primary reaction channel, and the M+-L yields and extent of multiple H-2-loss (i.e. the reactivity) generally paralleled the size of R. Primary products were: M+-C2H2 [R = C2H4]; M+-C3H4 [R = C3H6]; M+-C4H6 and M+-C4H4 [R = C4H8]; M+-C6H6 and M+-{C6H6}(2) [R = C6H10] and M+-C8H8 and M+-C8H6 [R = C8H12]. For cycloalkenes, C-C bond cleavage also occurred, e.g. M+ + C8H12 --> M+ -C6H6 + C2H6. The reactivity of Re+ was moderately greater than that of Tc+; thus for R = C6H10, the yield of Tc+-C6H6 and Re+-C6H6 were comparable but Tc+-C6H4 was minor relative to Re+-C6H4. Less coherent distinctions were observed between Tc+ and Mo+, although Tc+ was apparently slightly more reactive. Where ablated Mo+ were adequately abundant to measure Mof-L products, a greater reactivity, compared with naked Mf, was indicated; for R = C6H10 the product yields were: Tc+-C6H6/Tc+ approximate to 5% and TcO+-C6H6/TcO+ approximate to 40%. The especially facile reaction, Tc-2(+) + C4H8 -->Tc-2(+)-C4Hh + [(8 - h)/2]H-2 (h = 6 or 4), indicated greater reactivity for Tc-2(+) compared with Tc+ 'Closed-shell' (d(10)s(0)) Cu+ was relatively inert, generally producing primarily the adduct, Cu+-R (condensation was insignificant for other M+). However, Cu+ distinctively produced abundant Cu+-C4H6 (butadiene) from C6H10 and C8H12. The observed gas-phase organometallic chemistries of Cu+ and Mo+ are consistent with previous results by other techniques and with other organic substrates, and the reactivities of Tc+ and Re+ are in accord with general predictions. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Gibson, JK (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM jkg@ornl.gov NR 37 TC 7 Z9 7 U1 2 U2 13 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD MAY 15 PY 1998 VL 558 IS 1-2 BP 51 EP 60 DI 10.1016/S0022-328X(98)00400-8 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA ZU973 UT WOS:000074255300006 ER PT J AU Quintana-Orti, G Quintana-Orti, ES AF Quintana-Orti, G Quintana-Orti, ES TI Parallel codes for computing the numerical rank SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT 6th Conference of the International-Linear-Algebra-Society CY AUG 14-17, 1996 CL TU CHEMNITZ, CHEMNITZ, GERMANY SP Int Linear Algebra Soc HO TU CHEMNITZ ID MATRICES AB In this paper we present an experimental comparison of several numerical tools for computing the numerical rank of dense matrices. The study includes the well-known SVD, the URV decomposition, and several rank-revealing QR factorizations: the QR factorization with column pivoting, and two QR factorizations with restricted column pivoting. Two different parallel programming methodologies are analyzed in our paper. First, we present block-partitioned algorithms for the URV decomposition and rank-revealing QR factorizations which provide efficient implementations on shared memory environments. Furthermore, we also present parallel distributed algorithms, based on the message-passing paradigm, for computing rank-revealing QR factorizations on multicomputers. (C) 1998 Elsevier Science Inc. All rights reserved. C1 Univ Jaime I, Dept Informat, E-12071 Castellon, Spain. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Quintana-Orti, G (reprint author), Univ Jaime I, Dept Informat, Campus Penyeta Roja, E-12071 Castellon, Spain. EM gquintana@inj.uji.es; quintana@inf.uji.es NR 26 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD MAY 15 PY 1998 VL 276 BP 451 EP 470 PG 20 WC Mathematics, Applied; Mathematics SC Mathematics GA ZV225 UT WOS:000074282900026 ER PT J AU Taljat, B Radhakrishnan, B Zacharia, T AF Taljat, B Radhakrishnan, B Zacharia, T TI Numerical analysis of GTA welding process with emphasis on post-solidification phase transformation effects on residual stresses SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE finite element method; gas tungsten arc; residual stress state; neutron diffraction ID HEAT AB The objective of this work was to analyze the residual stress state in spot welds made in an MY-100 steel disk by an autogenous gas tungsten are (GTA) welding process. An uncoupled thermal-mechanical finite element (FE) model was developed that took into account the effects of liquid-to-solid and solid-stale phase transformations. Effects of variations in mechanical properties due to solid-state phase transformations on residual stresses in the weld were studied. Extensive experimental testing was carried out to determine the mechanical properties of MY-100 steel. The residual stresses in the disk with the spot weld were measured by a neutron diffraction (ND) technique. The FE results are in good agreement with the ND measurements. The results show that the volumetric changes associated with the austenite to martensite phase transformation in HY-100 steel significantly affect residual stresses in the weld fusion zone and the heat affected zone. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Taljat, B (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. OI Zacharia, Thomas/0000-0001-6463-5425 NR 17 TC 106 Z9 109 U1 6 U2 25 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 1998 VL 246 IS 1-2 BP 45 EP 54 DI 10.1016/S0921-5093(97)00729-6 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ZQ684 UT WOS:000073892700005 ER PT J AU Schneibel, JH Sabol, SM Joslin, DL AF Schneibel, JH Sabol, SM Joslin, DL TI On the high-temperature reactions between advanced ceramics and a cobalt-base alloy SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE ceramic/metallic interface; cobalt-base alloy; high-temperature reactions ID SILICON-NITRIDE; METALS AB The incorporation of advanced ceramics or ceramic composites into land-based turbines may potentially increase their efficiency due to increased gas inlet temperatures and/or reduced cooling requirements. In some proposed designs, incorporation of ceramics would require intimate contact of the ceramic and a metallic structure at elevated temperatures. Since many advanced ceramics contain Si. and since turbines are usually constructed out of Ni or Go-base alloys, the formation of Co or Ni silicides is expected at the ceramic/metallic interfaces. The goals of the present work are (a) an assessment of the microstructures and reaction products formed at ceramic/metallic interfaces during annealing at elevated temperatures and (b) a description of the kinetics of the reaction zone formation. Reaction couples consisting of the Go-base alloy ECY 768 and various advanced ceramics were prepared by hot-pressing in vacuum and subsequent annealing in vacuum or air at temperatures ranging from 1173 to 1323 K and for times ranging between 10 and 1000 h. Two types of silicon nitride (NT154 and AS800) and four whisker-reinforced alumina ceramics containing different weight fractions of SiC whiskers (ARtuff CC5500, S7, SX and CC7000) were investigated. The reaction zones consisted primarily of (Cr, Co) carbosilicides. The maximum reaction zone thicknesses after 1000 h at 1323 K were in most cases below 50 mu m. Whereas the reaction zones were well defined in the case of the silicon nitrides, the Al2O3/SiCW materials developed multiple silicide layers within the reaction zone. With increasing SiC whisker content, the reaction zones increased in thickness for a given heat treatment. A non-linear fitting procedure was employed to describe the reaction zone thicknesses in terms of apparent activation energies and pre-exponential factors. Whereas this procedure worked well for the silicon nitrides annealed in a vacuum, substantial scatter occurred for air anneals. The ARtuff materials always showed substantial scatter which is attributed to their layered reaction microstructure. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Westinghouse Power Generat, Orlando, FL 32826 USA. RP Schneibel, JH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 1998 VL 246 IS 1-2 BP 124 EP 132 DI 10.1016/S0921-5093(97)00741-7 PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ZQ684 UT WOS:000073892700014 ER PT J AU Lane, SM Biner, SB Buck, O AF Lane, SM Biner, SB Buck, O TI Room temperature fracture and high temperature creep characteristics of 20 vol.% Nb particulate reinforced alumina SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE ceramic composites; fracture toughness; crack bridging; creep ID BRITTLE-MATRIX COMPOSITES; DUCTILE REINFORCEMENTS; TOUGHNESS; CERAMICS; AL2O3; DEFORMATION; PHASE AB Composites consisting of an alumina matrix with 0.05 wt.% MgO and 20 vol.% Nb with an average particle size of 30 and 100 mu m, respectively, were produced by dry mixing and sintering to near their theoretical densities. Fracture toughness tests were carried out in three point bending on chevron notched samples. The results indicate that the R-curve of the composites exhibited a more than 300% increase in crack growth resistance compared with the crack growth resistance of the alumina produced by the identical procedure. The crack growth resistance curve of the composites increased with increasing Nb particle size. The metallographic investigations indicated that the failure of the Nb particles in the crack path ranged from full interface separation, without any significant deformation of Nb particles, to cleavage failure, without any evidence of interface separation. Although the creep rates of the composites were about an order of magnitude higher than those seen for the unreinforced matrix material with a grain size 9-14 mu m, they were similar to those seen for the unreinforced alumina having smaller grain sizes. In the creep regime, while grain boundary facet cracks, resulting from grain boundary cavitation, was widespread in the unreinforced alumina, localization of creep damage only to regions of the Nb particles was seen in the composites. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Biner, SB (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. EM sbbiner@iastate.edu NR 28 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 1998 VL 246 IS 1-2 BP 244 EP 251 DI 10.1016/S0921-5093(97)00703-X PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ZQ684 UT WOS:000073892700026 ER PT J AU Taranenko, NI Allman, SL Golovlev, VV Taranenko, NV Isola, NR Chen, CH AF Taranenko, NI Allman, SL Golovlev, VV Taranenko, NV Isola, NR Chen, CH TI Sequencing DNA using mass spectrometry for ladder detection SO NUCLEIC ACIDS RESEARCH LA English DT Article ID LASER-DESORPTION IONIZATION; MATRIX; EXTRACTION; OLIGONUCLEOTIDES; ACID AB Sequencing of DNA fragments of 130 and 200 bp using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for DNA ladder detection was demonstrated. With further improvement in mass resolution and detection sensitivity, mass spectrometry shows great promise for routine DNA sequencing in the future. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Yale Univ, Med Ctr, New Haven, CT USA. RP Chen, CH (reprint author), Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. EM chenc@ornl.gov RI Allman, Steve/A-9121-2011 OI Allman, Steve/0000-0001-6538-7048 NR 28 TC 46 Z9 47 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD MAY 15 PY 1998 VL 26 IS 10 BP 2488 EP 2490 DI 10.1093/nar/26.10.2488 PG 3 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZP804 UT WOS:000073790100033 PM 9580704 ER PT J AU Luce, BP AF Luce, BP TI Power enhancement with super-Gaussian sliding-frequency guiding filters SO OPTICS LETTERS LA English DT Article ID SOLITON TRANSMISSION CONTROL; BUTTERWORTH FILTERS AB I show with numerical simulations that higher-order sliding filters, especially super-Gaussian filters, can produce dramatic power enhancement of optical solitons, similar to that of dispersion-managed solitons. This approach should allow smaller timing jitter without sacrificing the signal-to-noise ratio. (C) 1998 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Luce, BP (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. NR 11 TC 4 Z9 4 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 1998 VL 23 IS 10 BP 765 EP 767 DI 10.1364/OL.23.000765 PG 3 WC Optics SC Optics GA ZM913 UT WOS:000073588900010 PM 18087335 ER PT J AU Hatano, N AF Hatano, N TI Localization in non-Hermitian quantum mechanics and flux-line pinning in superconductors SO PHYSICA A LA English DT Article; Proceedings Paper CT 1st Asia-Pacific and the 4th Taipei International Workshop/Symposium on Statistical Physics - New Directions in Statistical Physics (StatPhys-Taipei-1997) CY AUG 03-11, 1997 CL TAIPEI, TAIWAN DE localization; non-Hermitian; flux-line pinning; type-II superconductor ID LLOYD MODEL; SYSTEMS; DEFECTS; DENSITY; LENGTH AB A recent development in studies of random non-Hermitian quantum systems is reviewed. Delocalization was found to occur under a sufficiently large constant imaginary vector potential even in one and two dimensions. The phenomenon has a physical realization as flux-line depinning in type-II superconductors. Relations between the delocalization transition and the complex energy spectrum of the non-Hermitian systems are described. Analytical and numerical results obtained for a non-Hermitian Anderson model are shown. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hatano, N (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM hatano@viking.lanl.gov RI Hatano, Naomichi/K-8176-2012 OI Hatano, Naomichi/0000-0003-0277-1856 NR 44 TC 19 Z9 19 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 15 PY 1998 VL 254 IS 1-2 BP 317 EP 331 DI 10.1016/S0378-4371(98)00010-7 PG 15 WC Physics, Multidisciplinary SC Physics GA ZW585 UT WOS:000074426400031 ER PT J AU Jaffe, JE Lin, ZJ Hess, AC AF Jaffe, JE Lin, ZJ Hess, AC TI Gaussian-basis LDA and GGA calculations for alkali-metal equations of state SO PHYSICAL REVIEW B LA English DT Article ID GENERALIZED GRADIENT APPROXIMATION; DENSITY; ENERGY; FORMALISM; EXCHANGE; ELEMENTS; LITHIUM; SOLIDS AB Recently there has been renewed interest in implementations of density-functional theory for solids using various types of localized basis sets, including atom-centered Gaussian-type functions. While such methods are clearly well adapted to most insulating and semiconducting systems, one might expect them to give a less-than-optimal description of metals relative to plane-wave-type methods. Nevertheless, several successful applications of local-basis methods to metals have recently been reported. Here, we report an application of our Gaussian linear combination of atomic orbitals (LCAO) code to some extremely free-electron-like metals, namely, the alkali metals Li, Na, and K. In agreement with other calculations (both local and plane wave) we find that the local-density approximation (LDA) lattice constants are relatively poor (similar to-3% from experiment for the alkali metals versus +/-1% for many other solids) and that the LDA bulk moduli are similar to 30% too high. We find that the Perdew-Burke-Enzerhof (PBE) version of the generalized-gradient approximation (GGA) corrects most of this error, in agreement with earlier calculations using similar GGA functionals. The Becke-Lee-Yang-Parr GGA functional gives similar results for the alkali-metal equations of state but is found to overcorrect the errors of the LDA for the cohesive energies, for which the PBE functional is in better agreement with experiment. Our results indicate that the Gaussian-LCAO method should be able to give accurate results for nearly any crystalline solid, since it succeeds even where it would be expected to have the most difficulty. [S0163-1829(98)07919-3]. C1 Pacific NW Lab, Dept Mat Sci, Richland, WA 99352 USA. RP Pacific NW Lab, Dept Mat Sci, Richland, WA 99352 USA. RI Lin, Zijing/D-4050-2009 NR 26 TC 39 Z9 39 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 11834 EP 11837 DI 10.1103/PhysRevB.57.11834 PG 4 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500003 ER PT J AU Guerrero, M Gubernatis, JE Zhang, SW AF Guerrero, M Gubernatis, JE Zhang, SW TI Quantum Monte Carlo study of hole binding and pairing correlations in the three-band Hubbard model SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; TWO-DIMENSIONAL CUO2; PARAMETERS AB We simulated the three-band Hubbard model using the constrained-path Monte Carlo (CPMC) method in search for a possible superconducting ground state. The CPMC is a ground-state method that is free of the exponential scaling of computing time with system size. We calculated the binding energy of a pair of holes for systems up to 6x4 unit cells. We also studied the pairing correlation functions versus distance for both the d-wave and extended s-wave channels in systems up to 6x6. We found that holes bind for a wide range of parameters and that the binding increased as the system size is increased. However, the pairing correlation functions decay quickly with distance. For the extended s channel, we found that as the Coulomb interaction U-d on the Cu sites is increased, the long-range part of the correlation functions is suppressed and fluctuates around zero. For the d(x)2(-y)2 channel, we found that the correlations decay rapidly with distance towards a small positive value. However, this value becomes smaller as the interaction U-d Or the system size is increased. [S0163-1829(98)10919-0]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. RP Guerrero, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 25 TC 33 Z9 33 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 11980 EP 11988 DI 10.1103/PhysRevB.57.11980 PG 9 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500037 ER PT J AU Gole, JL Dixon, DA AF Gole, JL Dixon, DA TI Potential role of silanones in the photoluminescence-excitation, visible-photoluminescence-emission, and infrared spectra of porous silicon SO PHYSICAL REVIEW B LA English DT Article ID ROOM-TEMPERATURE PHOTOLUMINESCENCE; OPTICAL-PROPERTIES; VIBRATIONAL FREQUENCIES; LUMINESCENCE MECHANISM; MOLECULAR-STRUCTURE; PERTURBATION-THEORY; ANODIC-OXIDATION; SI NANOCRYSTALS; EXCITED-STATES; DEFECT CENTER AB Ab initio molecular electronic structure calculations on select silanones, silylenes, and tricoordinated silicon compounds SiXYZ with a dangling electron are presented. The calculations are used to evaluate the nature of the electronic spectra, which are to be associated with surface-bound Si/O/H compounds. In concert, they are used to suggest an explanation for the nature of the photoluminescence-excitation spectrum (PLE) and the subsequent visible luminescence (PL) from porous silicon (PS) based on the optical properties of the silanone-based oxyhydrides. In order to make this selection, we treat a set of compounds that includes the silanones Si(O)H-2, Si(O)H(OH), Si(O)(OH)(2), Si(O)H(OSiH3), Si(O)H(SiH3), Si(O)(OH)(SiH3), Si(O)(SiH3)(2), and Si(O)(SiH3)(OSiH3), the silylenes HSiOH, HOSiOH, and HOSiOSiH3, and the tricoordinated silicon compounds SiH3, Si(OH)H-2, Si(OH)(2)H, and Si(OH)(3). The silanone-based oxyhydride structures containing either an OH or OSiH3 group all display adiabatic ground-state singlet-excited-state triplet exciton separations in the range close to 400 nm. This adiabatic energy is consistent with the vertical transition energies associated with the PS excitation spectrum (PLE) as a large change in the Si=O bond distance (similar to 0.17 Angstrom) accompanies the transition from the silanone ground electronic singlet state to the low-lying triplet exciton (or its closely lying singlet coupled configuration). The maximum in the PLE spectrum, obtained through optical pumping from the lowest vibrational levels of the ground electronic state to considerably higher levels of the triplet exciton electronic state, should therefore be shifted to considerably shorter wavelength consistent with an absorption spectrum peaking at 350 nm as observed by several researchers. A shift to larger internuclear distance in the excited-state tripler exciton will also produce a considerable redshift in the PL emission spectrum relative to the absorption-excitation wavelengths, again consistent with experimental observation. The calculated IR spectra for the silanone-based oxyhydrides are also consistent with the observed Fourier transform IR spectra of porous silicon. In clear contrast, neither the silylenes nor the tricoordinated silicon compounds with dangling electrons can account for the excitation or emission features that are associated with PS as their lowest-lying transitions result in minimal changes in bonding and/or occur at much higher energy (shorter wavelength). The results obtained in this study also suggest that surface passivation or the saturation of valency is incommensurate with the formation of the fluorophors that will produce the emission from PS. [S0163-1829(98)08619-6]. C1 Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. NR 85 TC 61 Z9 62 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12002 EP 12016 DI 10.1103/PhysRevB.57.12002 PG 15 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500040 ER PT J AU Watson, RE Weinert, M Alatalo, M AF Watson, RE Weinert, M Alatalo, M TI Ternary transition-metal aluminide alloy formation: The BiF3 structure SO PHYSICAL REVIEW B LA English DT Article AB Almost 50 ternary transition-metal aluminides have been reported in the ordered BiF3 structure, representing roughly half of the observed ordered ternaries. To investigate the possible occurrence of other aluminides in this structure, the heats of formation of 38 ordered M2NAl ternaries, most not reported to occur, have been calculated. While all but one is stable relative to the elemental metals, the test for ternary stability requires comparison of the ternary heat with competing two and three phase mixtures of binary phases. Of the BiF3 ternaries hitherto unreported, nine are estimated to occur while eighteen are found to be unstable. The pattern of occurrence obtained from experiments and calculations taken together suggests that on the order of another 20 compounds beyond those predicted here could exist. Thus, this important ordered phase is more pervasive than previously suggested by experiment. [S0163-1829(98)01720-2]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Watson, RE (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 15 TC 21 Z9 21 U1 2 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12134 EP 12139 DI 10.1103/PhysRevB.57.12134 PG 6 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500055 ER PT J AU Williamson, AJ Hood, RQ Needs, RJ Rajagopal, G AF Williamson, AJ Hood, RQ Needs, RJ Rajagopal, G TI Diffusion quantum Monte Carlo calculations of the excited states of silicon SO PHYSICAL REVIEW B LA English DT Article ID WAVE-FUNCTIONS; ELECTRONIC-STRUCTURE; SOLIDS; SEMICONDUCTORS; POTENTIALS; MOLECULES; DIAMOND; ENERGY; ATOMS AB The band structure of silicon is calculated at the Gamma, X, and L wave vectors using diffusion quantum Monte Carlo (DMC) methods. Excited states are formed by promoting an electron from the valence band into the conduction band. We obtain good agreement with experiment for states around the gap region, and demonstrate that the method works equally well for direct and indirect excitations, and that one can calculate many excited states at each wave vector. This work establishes the fixed-node DMC approach as an accurate method for calculating the energies of low-lying excitations in solids. [S0163-1829(98)11819-2]. C1 Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England. RP Williamson, AJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Cavendish, TCM/C-9489-2009; Needs, Richard/C-2931-2013 NR 25 TC 60 Z9 60 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12140 EP 12144 DI 10.1103/PhysRevB.57.12140 PG 5 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500056 ER PT J AU Navarro-Contreras, H de Anda-Salazar, F Hsu, L Haller, EE AF Navarro-Contreras, H de Anda-Salazar, F Hsu, L Haller, EE TI DX-center transformation of Te donors in GaSb under hydrostatic pressure SO PHYSICAL REVIEW B LA English DT Article ID FREE-CARRIER ABSORPTION; INFRARED-ABSORPTION; BAND LINEUPS; SEMICONDUCTORS; GAAS; PHONONS; SPECTROSCOPY; SCATTERING; ALXGA1-XAS; OFFSETS AB We have observed the transformation of Te shallow donors in GaSb into DX centers at hydrostatic pressures of 27.8+/-2.6 kbar. The position of the Te DX energy level at zero pressure is calculated to lie 300+/-70 meV above the conduction band at atmospheric pressure, consistent with the theory that in the III-V compounds the DX centers line up in energy with respect to the vacuum level within experimental error. This binding energy at zero pressure of the Te DX compares well with the value of 210 meV calculated from the cation-cation bonded DX-center model recently proposed by Park and Chadi. At pressures where the Te shallow donor into DX-center transformation has taken place we observe evidence of the existence of a bound phonon associated with the Te DX center. From its observed pressure dependence the LO optical phonon Gruneisen parameter is calculated to be gamma(LO)=0.93+/-0.09. [S0163-1829(98)11419-4]. C1 Univ Autonoma San Luis Potosi, Inst Invest Comun Opt, San Luis Potosi 78000, Mexico. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Navarro-Contreras, H (reprint author), Univ Autonoma San Luis Potosi, Inst Invest Comun Opt, Alvaro Obregon 64, San Luis Potosi 78000, Mexico. RI NAVARRO-CONTRERAS, HUGO/D-4074-2012 NR 37 TC 4 Z9 4 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12169 EP 12173 DI 10.1103/PhysRevB.57.12169 PG 5 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500061 ER PT J AU Shkrob, IA Crowell, RA AF Shkrob, IA Crowell, RA TI Ultrafast charge recombination in undoped amorphous hydrogenated silicon SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; PICOSECOND PHOTOINDUCED ABSORPTION; LIGHT-INDUCED DEFECTS; THIN-FILMS; PHOTOMODULATION-SPECTROSCOPY; BIMOLECULAR RECOMBINATION; FEMTOSECOND SPECTROSCOPY; GEMINATE RECOMBINATION; FREE-CARRIER; GE-H AB Nonradiative bimolecular recombination of photocarriers in room-temperature a-Si:H films was studied as a function of the photocarrier density and excitation energy, using ultrafast laser spectroscopy over the range of 150 fs to 4 ns. It is demonstrated that for excitation with photons whose energy exceeds the optical gap of a-Si:H, 1.7 eV, the time-evolution of transient absorbance (detected at 1.5-1.6 eV) depends only on the initial density N-ex of the photocarriers (>10(18) cm(-3)). For N(ex)similar to 5 x 10(18) to 2 X 10(20) cm(-3), the bimolecular decay of the photocarriers is bimodal: In the first few picoseconds the decay kinetics are controlled by recombination and trapping of free carriers, whereas at later delay times the kinetics are controlled by intraband migration of the trapped charges and their recombination with thermally emitted free carriers. An analysis of the decay kinetics in the framework of the multiple-trapping model (which included mesoscopic nonuniformity of the photocarrier generation) gave the rate constants of 2.3x10(-8) and 6x10(-9) cm(-3)/s for the fast and slow components of the recombination kinetics, respectively. This bimodality accounts fora considerable spread of bimolecular rate constants found in the literature. Our results seem to be incompatible with the previously suggested models of Auger process in undoped a-Si:H. This work emphasizes the need for further theoretical understanding of the recombination mechanisms involved. We argue that in the low-density regime, the direct bimolecular recombination of the excess charges can be a "rare event" that causes the Staebler-Wronsky effect. [S0163-1829(98)06219-5]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Shkrob, IA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 73 TC 23 Z9 23 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12207 EP 12218 DI 10.1103/PhysRevB.57.12207 PG 12 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500065 ER PT J AU Zhang, Y Mascarenhas, A AF Zhang, Y Mascarenhas, A TI Electronic and optical properties of laterally composition-modulated AlxIn1-xAs, GaxIn1-xP, and GaxIn1-xAs alloys SO PHYSICAL REVIEW B LA English DT Article ID LAYER ORDERING PROCESS; QUANTUM-WIRE HETEROSTRUCTURES; SHORT-PERIOD SUPERLATTICES; STRAIN; WELLS; TRANSITIONS AB Results of a systematic study of the band structure and optical properties of laterally-composition-modulated semiconductor alloys AlxIn1-xAs, GaxIn1-xP, and GaxIn1-xAs are reported. [110] composition modulation occurs spontaneously during growth of (001) short-period superlattices or bulk epilayers of these alloys. The effect of this long-range lateral modulation is modeled using k . p theory and the envelope-function approximation, while the vertical short-period superlattice is emulated by a uniaxial perturbation. We have studied the dependence of the electronic and optical properties of such structures on the modulation amplitude, profile, and negative feedback due to the coherency strain field. We find that (i) among the three-alloy systems, for a given modulation amplitude, the largest band-gap reduction can be achieved in AlxIn1-xAs, and the smallest in GaxIn1-xAs, (ii) a step-function modulation gives a larger band-gap reduction than a sinusoidal modulation; (iii) when the coherency strain is tetragonal in the modulated direction, a strong in-plane optical anisotropy is expected and when it is tetragonal in the growth direction, a weak in-plane optical anisotropy is anticipated; (iv) the vertical short-period superlattice enhances the band-gap reduction, but reduces the in-plane optical anisotropy; and (v) the lateral composition modulation is inherently associated with a diminishing of the vertical short-period superlattice. The possibility and conditions of type-II band alignment in these modulated structures are discussed. [S0163-1829(98)05519-2]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Zhang, Y (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 36 TC 33 Z9 33 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12245 EP 12254 DI 10.1103/PhysRevB.57.12245 PG 10 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500070 ER PT J AU Leung, K Pokrant, S Whaley, KB AF Leung, K Pokrant, S Whaley, KB TI Exciton fine structure in CdSe nanoclusters SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM DOTS; EXCHANGE INTERACTION; ELECTRONIC-STRUCTURE; MATRIX-ELEMENTS; STOKES SHIFT; SEMICONDUCTORS; NANOCRYSTALS; ABSORPTION; SURFACE; BAND AB The fine structure in the CdSe nanocrystal absorption spectrum is computed by-incorporating two-particle electron-hole interactions and spin-orbit coupling into a tight-binding model, with an expansion iq electron-hole single-particle states. The exchange interaction and spin-orbit coupling give rise to dark, low-lying states that are predominantly triplet in character, as well as to a manifold of exciton states that are sensitive to the nanocrystal shape. Near the band gap, the exciton degeneracies are in qualitative agreement with the effective mass approximation (EMA). However instead of the infinite lifetimes for dark states characteristic of the EMA, we obtain finite radiative lifetimes for the dark states. In particular, for the lowest, predominantly triplet, states we obtain radiative lifetimes of microseconds, in qualitative agreement with the experimental measured lifetimes. The resonant Stokes shifts obtained from the splitting between the lowest dark and bright states are also in good agreement with experimental values for larger crystallites. Higher-lying states exhibit significantly more complex behavior than predicted by EMA, due to extensive mixing of electron-hole pair states. [S0163-1829(98)06619-3]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Leung, K (reprint author), Sandia Natl Labs, MS 1421, Albuquerque, NM 87185 USA. RI Pokrant, Simone/O-6124-2016 OI Pokrant, Simone/0000-0003-3566-4950 NR 54 TC 98 Z9 98 U1 2 U2 24 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12291 EP 12301 DI 10.1103/PhysRevB.57.12291 PG 11 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500076 ER PT J AU Schreiber, F Eberhardt, A Leung, TYB Schwartz, P Wetterer, SM Lavrich, DJ Berman, L Fenter, P Eisenberger, P Scoles, G AF Schreiber, F Eberhardt, A Leung, TYB Schwartz, P Wetterer, SM Lavrich, DJ Berman, L Fenter, P Eisenberger, P Scoles, G TI Adsorption mechanisms, structures, and growth regimes of an archetypal self-assembling system: Decanethiol on Au(111) SO PHYSICAL REVIEW B LA English DT Article ID N-ALKYL THIOLS; GOLD; SPECTROSCOPY; MONOLAYERS; KINETICS; SURFACE; ALKANETHIOLS; PHASE AB We present a study using several techniques of the growth of decanethiol monolayers deposited on single-crystal gold surfaces. Through independent measurements of coverage, energetics, and structure as a function of the growth rate and temperature, we provide a quantitative, in-depth description of the molecular precesses by which these aliphatic molecules "self-assemble" into highly ordered structures in the absence of a solvent. We find that the multiple-energy scales present in these systems produce distinct adsorption mechanisms, structures, and growth regimes, indicating a complexity that is likely to be a general characteristic of this broad class of self-assembling systems. C1 Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. RP Schreiber, F (reprint author), Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. RI Schreiber, Frank/J-3311-2014; OI Schreiber, Frank/0000-0003-3659-6718; Fenter, Paul/0000-0002-6672-9748 NR 27 TC 143 Z9 143 U1 4 U2 35 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12476 EP 12481 DI 10.1103/PhysRevB.57.12476 PG 6 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500099 ER PT J AU Bardotti, L Stoldt, CR Jenks, CJ Bartelt, MC Evans, JW Thiel, PA AF Bardotti, L Stoldt, CR Jenks, CJ Bartelt, MC Evans, JW Thiel, PA TI High-resolution LEED profile analysis and diffusion barrier estimation for submonolayer homoepitaxy of Ag/Ag(100) SO PHYSICAL REVIEW B LA English DT Article ID ENERGY-ELECTRON-DIFFRACTION; EPITAXIAL-GROWTH; 1ST STAGES; NUCLEATION; AG; SURFACES; CU(100); AG(100); COALESCENCE; ISLANDS AB We present a high-resolution low-energy electron diffraction study of two-dimensional island distributions formed by depositing 0.3 ML of Ag on Ag(100). The substrate temperature ranged between 170 and 295 K. From the ring structure or "splitting" of the diffraction profiles, we determine the behavior of the spatial correlation length characterizing the island distribution. The precise relationship between this correlation length and the mean island separation is also determined via an analysis of kinematic diffraction from island distributions in a realistic model of nucleation and growth. Resulting estimates of this separation are consistent with those based on results from a previous scanning tunneling microscopy study at 295 K. From the Arrhenius behavior of the correlation length, we estimate a terrace diffusion barrier for Ag on AE(100) of 0.40 +/- 0.04 eV, with a vibrational prefactor of about 3 X 10(13) s(-1). C1 Iowa State Univ, IPRT, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, IPRT, Dept Math, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Bardotti, L (reprint author), Univ Lyon 1, Dept Phys Mat, F-69622 Villeurbanne, France. NR 35 TC 37 Z9 37 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12544 EP 12549 DI 10.1103/PhysRevB.57.12544 PG 6 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500108 ER PT J AU Kiely, JD Houston, JE AF Kiely, JD Houston, JE TI Nanomechanical properties of Au (111), (001), and (110) surfaces SO PHYSICAL REVIEW B LA English DT Article ID NANOMETER-SCALE MECHANICS; INDENTATION EXPERIMENTS; FORCE MICROSCOPY; MONOLAYER FILMS; GOLD-FILMS AB Using the interfacial force microscope in an indentation mode, we have quantitatively investigated the mechanical properties for the (111), (001), and (110) surfaces of Au single crystals. Nanoscale indentations of wide, atomically flat terraces provide a measure of the nanomechanical properties of Au in the absence of bulk and surface defects. The elastic indentation modulus for the (111) surface was found to be 36% greater than for the (001) and 3% greater than for the (110) surfaces. These results are compared to earlier theoretical predictions of the effect of anisotropy on indentation based on continuum mechanics and atomistic simulations. Additionally, we have quantified the yield point of the three crystal orientations by measuring the stress at which initial plastic deformation occurs. By resolving the applied stresses on {111} slip planes, we have estimated maximum shear stresses at the yield point. For each orientation, plastic deformation occurred when the maximum resolved shear stress reached approximately 1.8 GPa on all {111} planes that appeared to contribute to deformation. Based on this estimate, we propose that the critical resolved shear stress for plastic indentation of Au is 1.8 GPa and that the yield criterion is that this stress be attained on all {111} slip planes noncoplanar with the surface. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Kiely, JD (reprint author), Sandia Natl Labs, Surface & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 34 TC 208 Z9 209 U1 8 U2 46 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12588 EP 12594 DI 10.1103/PhysRevB.57.12588 PG 7 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500114 ER PT J AU Dunphy, JC Rose, M Behler, S Ogletree, DF Salmeron, M Sautet, P AF Dunphy, JC Rose, M Behler, S Ogletree, DF Salmeron, M Sautet, P TI Acetylene structure and dynamics on Pd(111) SO PHYSICAL REVIEW B LA English DT Article ID TRANSFORM MASS-SPECTROMETRY; VIBRATIONAL SPECTROSCOPY; MOLECULAR-DYNAMICS; BENZENE FORMATION; SURFACES; KINETICS AB Acetylene molecules adsorbed onto a Pd(111) crystal surface were imaged by scanning tunneling microscopy (STM) below 70 K. Single C2H2 molecules appeared as a combination of a protrusion and a depression 3.5 Angstrom apart. This peculiar shape is due to the molecular pi orbital, which is oriented at a shallow angle out of the surface. Six orientations of the molecule with respect to the substrate were observed, indicating two different threefold hollow binding sites each with three possible rotational states. At 44 K, thermally activated rotation of the molecules between the three equivalent states on the same threefold hollow site occurs on the time scale of seconds. Diffusion of molecules between adjacent threefold sites began at similar to 70 K. The findings agree with the structure of the adsorption site determined by total-energy calculations and with the STM image calculated using the electron scattering quantum chemistry method. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Ecole Normale Super Lyon, Chim Theor Lab, F-69364 Lyon, France. Inst Rech Catalyse, CNRS, F-69626 Villeurbanne, France. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Candescent Technol, 6580 Via Oro, San Jose, CA 95119 USA. EM salmeron@stm.lbl.gov RI Sautet, Philippe/G-3710-2014 OI Sautet, Philippe/0000-0002-8444-3348 NR 15 TC 50 Z9 50 U1 0 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 20 BP 12705 EP 12708 PG 4 WC Physics, Condensed Matter SC Physics GA ZR644 UT WOS:000073999400016 ER PT J AU Jimenez, I Sutherland, DGJ van Buuren, T Carlisle, JA Terminello, LJ Himpsel, FJ AF Jimenez, I Sutherland, DGJ van Buuren, T Carlisle, JA Terminello, LJ Himpsel, FJ TI Photoemission and x-ray-absorption study of boron carbide and its surface thermal stability SO PHYSICAL REVIEW B LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; INNER-SHELL EXCITATION; AMORPHOUS-CARBON FILMS; FINE-STRUCTURE; THIN-FILMS; BORANES; CARBORANES; ATOMS; ION; DIFFRACTION AB We present a photoemission and x-ray-absorption study on boron carbide which identifies the spectroscopic features of this material, discussing them in connection with current structural models. A study on the surface thermal stability is also performed, revealing that despite the high melting point of boron carbide (similar to 2600 K), significant surface modifications occur in the material at about 1800 K. At this temperature the surface becomes covered with a graphite layer formed from bulk segregation of carbon, leaving boron-rich boron carbide buried beneath the graphitic surface. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Jimenez, I (reprint author), Inst Ciencia Mat Madrid, E-28049 Canto Blanco, Spain. EM ijimenez@icmm.csic.es RI Jimenez, Ignacio/F-7422-2010 OI Jimenez, Ignacio/0000-0001-5605-3185 NR 45 TC 89 Z9 89 U1 1 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 20 BP 13167 EP 13174 DI 10.1103/PhysRevB.57.13167 PG 8 WC Physics, Condensed Matter SC Physics GA ZR644 UT WOS:000073999400068 ER PT J AU Lucas, CA Markovic, NM Ross, PN AF Lucas, CA Markovic, NM Ross, PN TI Underpotential deposition of Cu on Pt(001): Interface structure and the influence of adsorbed bromide SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-SCATTERING; SCANNING-TUNNELING-MICROSCOPY; BY-LAYER GROWTH; SINGLE-CRYSTAL SURFACES; ELECTROLYTE INTERFACE; PT(111)-SOLUTION INTERFACE; RECONSTRUCTED PT(100); ATOMIC-STRUCTURE; DISK ELECTRODE; COPPER AB Using in situ x-ray diffraction, we studied the underpotential deposition (UPD) of copper onto a Pt(001) electrode both in pure perchloric acid and in the presence of bromide anions. In pure perchloric acid, the Cu is deposited in pseudomorphic p(1x1) islands. In the presence of bromide anions, the strong Pt-Br interaction significantly broadens the potential range of Cu UPD. We propose that Pr remains in the interface region throughout the UPD process, at first in a disordered Cu-Br phase and then, at more negative potential, forming a c(2x2) closed-packed monolayer on top of the completed p(1X1) Cu monolayer. The structures are compared to those found during Cu UPD onto Pt(111), and explained in terms of the metal-halide interactions and the Pt surface atomic geometry. C1 Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Lucas, CA (reprint author), Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. OI Lucas, Christopher/0000-0001-5743-3868 NR 63 TC 11 Z9 11 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 20 BP 13184 EP 13191 DI 10.1103/PhysRevB.57.13184 PG 8 WC Physics, Condensed Matter SC Physics GA ZR644 UT WOS:000073999400070 ER PT J AU Choi, HJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Bader, SD AF Choi, HJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Bader, SD TI Magnetic anisotropy of epitaxial Fe films grown on curved W(001) with a graded step density SO PHYSICAL REVIEW B LA English DT Article ID ULTRATHIN FILMS; IRON FILMS; SURFACES; W(100) AB Ultrathin Fe films were grown epitaxially onto a stepped W(001) substrate, polished with a curvature to provide a continuously variable step density, with the steps parallel to the [100] crystalline axis. The steps induce an in-plane uniaxial magnetic anisotropy with easy axis perpendicular to the step edges. We found that this step-induced magnetic anisotropy does not enhance the Curie temperature of the Fe film. The strength of the anisotropy varies quadratically with step density, but does not decay with 1/d dependence expected for a surface-type anisotropy. We suggest that strain at the step edges might underlie the result. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Choi, HJ (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Bader, Samuel/A-2995-2013; Qiu, Zi Qiang/O-4421-2016 OI Qiu, Zi Qiang/0000-0003-0680-0714 NR 25 TC 9 Z9 9 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 20 BP R12713 EP R12716 DI 10.1103/PhysRevB.57.R12713 PG 4 WC Physics, Condensed Matter SC Physics GA ZR644 UT WOS:000073999400018 ER PT J AU Kiers, K Tytgat, MHG AF Kiers, K Tytgat, MHG TI Neutrino ground state in a dense star SO PHYSICAL REVIEW D LA English DT Article ID EXTENDED-HADRON MODELS; LONG-RANGE FORCES; NONPERTURBATIVE METHODS; FIELD-THEORY; OSCILLATIONS; MATTER; SPECTROSCOPY; DERIVATION AB Tt has recently been argued that long range forces due to the exchange of massless neutrinos give rise to a very large self-energy in a dense, finite-ranged, weakly charged medium. Such an effect, if real, would destabilize a neutron star. To address this issue we have studied the related problem of a massless neutrino field in the presence of an external, static electroweak potential of finite range, To be precise, we have computed to one loop the exact vacuum energy for the case of a spherical square well potential bf depth alpha and radius R. For small wells, the vacuum energy is reliably determined by a perturbative expansion in the external potential. For large wells, however, the perturbative expansion breaks down. A manifestation of this breakdown is that the vacuum carries a non-zero neutrino charge. The energy and neutrino charge of the ground state are, to a good approximation for large wells, those of a neutrino condensate with chemical potential mu = alpha. Our results demonstrate explicitly that long-range forces due to the exchange of massless neutrinos do not threaten the stability of neutron stars. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Libre Bruxelles, Serv Phys Theor, B-1050 Brussels, Belgium. RP Kiers, K (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 33 TC 24 Z9 26 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1998 VL 57 IS 10 BP 5970 EP 5981 DI 10.1103/PhysRevD.57.5970 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZP577 UT WOS:000073767400007 ER PT J AU Kallosh, R Kumar, J Rajaraman, A AF Kallosh, R Kumar, J Rajaraman, A TI Special conformal symmetry of world volume actions SO PHYSICAL REVIEW D LA English DT Article AB Kappa-symmetric worldvolume actions of the D3-, M5-, and M2-branes can he coupled consistently to their near horizon bosonic geometry background. We study the gauge-fixed action in the approximation in which only the transverse radial direction of the brane is allowed to fluctuate. The generalized special conformal symmetry of these self-interacting actions is established. This opens up the possibility to find out if the full superconformal symmetry of the free actions of these branes survives in the presence of coupling defined by the size of the anti-de Sitter throat. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Kallosh, R (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94305 USA. NR 9 TC 27 Z9 28 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1998 VL 57 IS 10 BP 6452 EP 6454 DI 10.1103/PhysRevD.57.6452 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZP577 UT WOS:000073767400054 ER PT J AU Bartos, I Van Hove, MA Chung, WF He, Z Altman, MS AF Bartos, I Van Hove, MA Chung, WF He, Z Altman, MS TI Ag(111) electron band structure and channeling by VLEED SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 17th European Conference on Surface Science CY SEP 16-19, 1997 CL ENSCHEDE, NETHERLANDS DE electron band structure; electron channeling; silver; very low electron energy diffraction (VLEED) AB Very-low energy electron diffraction (VLEED) provides useful evidence about the electron band structure of crystal surfaces above the vacuum level. The intensity of the normally incident beam has been measured in detail for Ag(111) in the range 5-35 eV by a low-energy electron microscope. A sharp resonance, as found for Cu(111) [I. Bartos, M.A. Van Hove, M.S. Altman, Surf. Sci. 352-354 (1996) 660] below the Bragg peak, is connected with the local energy band gap. Good agreement of the I-V curves with theoretical calculations is obtained (in particular the small width of the resonance) when electron channeling along the surface is taken into account. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Acad Sci Czech Republ, Inst Phys, Prague, Czech Republic. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Hong Kong Univ Sci & Technol, Dept Phys, Kowloon, Hong Kong. RP Bartos, I (reprint author), Acad Sci Czech Republ, Inst Phys, Prague, Czech Republic. RI Van Hove, Michel/A-9862-2008; Bartos, Igor/G-5780-2014 OI Van Hove, Michel/0000-0002-8898-6921; NR 10 TC 11 Z9 11 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 15 PY 1998 VL 402 IS 1-3 BP 697 EP 700 DI 10.1016/S0039-6028(97)00957-6 PG 4 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZY342 UT WOS:000074610800143 ER PT J AU Choquette, KD Hadley, GR Hou, HQ Geib, KM Hammons, BE AF Choquette, KD Hadley, GR Hou, HQ Geib, KM Hammons, BE TI Leaky mode vertical cavity lasers using cavity resonance modification SO ELECTRONICS LETTERS LA English DT Article ID SURFACE-EMITTING LASERS; OPERATION; ARRAYS AB Singlemode operation of selectively oxidised monolithic vertical cavity laser diodes is demonstrated using optical antiguiding induced by cavity resonance modifications. A higher refractive index surrounding the laser cavity is accomplished by increasing the optical cavity length in this region to form leaky-mode lasers. The monolithic antiguiding lasers are fabricated using an etch and regrowth process of the top semiconductor distributed Bragg reflector mirror. The leaky-mode vertical cavity lasers exhibit single transverse mode operation up to injection currents greater than 13 times the threshold current. C1 Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, POB 5800-MS0603, Albuquerque, NM 87185 USA. EM kdchoqu@sandia.gov NR 13 TC 29 Z9 29 U1 0 U2 1 PU INST ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 EI 1350-911X J9 ELECTRON LETT JI Electron. Lett. PD MAY 14 PY 1998 VL 34 IS 10 BP 991 EP 993 DI 10.1049/el:19980744 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA ZR317 UT WOS:000073962000041 ER PT J AU Martin, RL Hay, PJ Pratt, LR AF Martin, RL Hay, PJ Pratt, LR TI Hydrolysis of ferric ion in water and conformational equilibrium SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DENSITY-FUNCTIONAL THEORY; FREE-ENERGY; STATISTICAL-MECHANICS; BINDING-ENERGIES; DIELECTRIC MODEL; HYDRATION; DYNAMICS; IRON(III); ABINITIO; EXCHANGE AB Reported here are results of theoretical calculations on Fe(H2O)(6)(3+), Fe(H2O)(5)(OH)(2+), three isomers of Fe(H2O)(4)(OH)(2)(+), and Fe(H2O)(3)(OH)(2)(+), which investigate the molecular mechanisms of hydrolysis of ferric ion in water. The combination of density functional electronic structure techniques and a dielectric continuum model for electrostatic solvation applied to the Fe(H2O)(6)(3+) complex yields an estimate of -1020 kcal/mol (experimental values -1037 to -1019 kcal/mol) for the absolute free energy of the aqueous ferric ion. The predicted free energy change for the first hydrolysis reaction is surprisingly close to the experimental value (2 kcal/mol predicted compared to 3 kcal/mol experimental). For the second hydrolysis reaction, we found an unexpected low-energy isomer of Fe(H2O)(4)(OH)(2)(+) with five ligands in the inner sphere and one water outside. The hexacoordinate cis and trans isomers are, respectively, slightly lower and higher in energy. Calculations on the pentacoordinate species Fe(H2O)(3)(OH)(2)(+) suggest that extrusion of the outer-sphere water is nearly thermoneutral. The reaction free energy for the second hydrolysis is predicted in the range 16-18 kcal/mol, higher than the experimental value of 5 kcal/mol. Because the theoretical predictions are higher than experimental values, and novel structures were encountered among products of the second hydrolysis, we argue that conformational entropy is an important omission in this theoretical treatment of net reaction free energies. A fuller cataloging of low-energy hydrolysis products and direct calculations of partition functions of the isolated complexes should help in modeling equilibrium speciation in groundwaters. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Martin, RL (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Pratt, Lawrence/H-7955-2012 OI Pratt, Lawrence/0000-0003-2351-7451 NR 56 TC 221 Z9 221 U1 3 U2 55 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 14 PY 1998 VL 102 IS 20 BP 3565 EP 3573 DI 10.1021/jp980229p PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZP701 UT WOS:000073779800014 ER PT J AU Rieutord, F Salmeron, M AF Rieutord, F Salmeron, M TI Wetting properties at the submicrometer scale: A scanning polarization force microscopy study SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID DROPLETS; LIQUIDS; SIZE AB Submicrometer size droplets of sulfuric acid on mica have been imaged using scanning polarization force microscopy (SPFM). Our study shows that, contrary to the macroscopic case, the drop profile depends on the size of the drops, with a decrease of the contact angle with decreasing size droplets in the present case. This dependence can be explained by taking into account long-range forces between the substrate and the fluid, which prove to have important effects for submicrometer size drops. Profile measurements at the submicron scale allow direct estimation of the interaction potential between a fluid and a substrate. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. CEA, SI3M, Dept Rech Fondamentale Mat Condensee, F-38054 Grenoble 9, France. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM salmeron@stm.lbl.gov NR 21 TC 37 Z9 40 U1 2 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 14 PY 1998 VL 102 IS 20 BP 3941 EP 3944 DI 10.1021/jp980149l PG 4 WC Chemistry, Physical SC Chemistry GA ZP698 UT WOS:000073779500015 ER PT J AU Wu, HM Ratsep, M Jankowiak, R Cogdell, RJ Small, GJ AF Wu, HM Ratsep, M Jankowiak, R Cogdell, RJ Small, GJ TI Hole-burning and absorption studies of the LH1 antenna complex of purple bacteria: Effects of pressure and temperature SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PIGMENT-PROTEIN COMPLEXES; B820 SUBUNIT FORM; RHODOBACTER-SPHAEROIDES; ENERGY-TRANSFER; RHODOPSEUDOMONAS-ACIDOPHILA; BACTERIOCHLOROPHYLL-PROTEIN; ELECTRONIC EXCITATION; PROTOPORPHYRIN-IX; OPTICAL-SPECTRA; DYNAMICS AB Spectral hole-burning and absorption spectroscopies were combined with pressure and temperature in studies of the light harvesting 1 (LH1 or B875) antenna complex of wild-type (WT) chromatophores and an LH1-only mutant of Rhodobacter sphaeroides. Zero-phonon hole (ZPH) action spectra lead to values of 120 (WT) and 140 cm(-1) (mutant) for the separation (Delta E) between the lowest energy exciton level of A symmetry, B896, and the adjacent, strongly absorbing E-1 level of the C-16 ring of 32 bacteriochlorophyll a molecules. The E-1 level is responsible for most of the B875 band's absorption intensity. Values for the inhomogeneous broadening of the relatively weak B896 absorption band are given. High-pressure hole-burning data for the B896 band yielded a very large linear pressure shifting of -0.67 cm(-1)/MPa, about 10% higher than the shift rate for the B875 absorption band. These shifts are about a factor of 7 times higher than those of weakly coupled chlorophyll molecules in protein complexes and isolated chromophores in polymers and glasses. A theoretical model is presented which leads to the conclusion that electron-exchange coupling between nearest neighbor BChl a molecules of the B875 ring is largely responsible for the large pressure shifts. (Such coupling produces charge-transfer (CT) states which mix with the neutral (1) pi pi* states of the BChl a molecules.) It follows that a firm understanding of the excitonic structure of the B875 ring is unachievable by consideration of only electrostatic interactions. These conclusions also apply to the B850 BChl a ring of the LH2 complex. The data from the pressure studies can be used as benchmarks for electronic structure calculations which take into account both electrostatic and CT interactions. Thermal broadening and shifting data for the B875 band establish that the LH1 complex undergoes a nondenaturing structural change at similar to 150 K in a glycerol/water glass, as has been reported for the LH2 complex. The structural change occurs for chromatophores and isolated complexes. The ability to detect the subtle structural change via the B875 and B850 bands is a consequence of strong coupling between BChl a molecules of the B875 and B850 rings. The results of the high-pressure experiments indicate that CT is an important contributor to the coupling and that the structural change may not be detectable by X-ray diffraction at typical similar to 2 Angstrom resolution. Theoretical models from Wu et al. (J. Phys. Chem. B 1997, 101, 7641) provide a satisfactory explanation for the thermal shifting and broadening of the B875 band. The broadening is dynamic, the result of interexciton level downward relaxation triggered by a low-frequency, intermolecular promoting model(s) which modulate nearest neighbor couplings: The nearest neighbor BChl a-BChl a couplings for the low-temperature structure of the B875 ring are estimated to be 30% stronger than those of the high-temperature structure. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Glasgow, Inst Biomed & Life Sci, Div Biochem & Mol Biol, Glasgow G12 8QQ, Lanark, Scotland. RP Small, GJ (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. NR 68 TC 50 Z9 50 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 14 PY 1998 VL 102 IS 20 BP 4023 EP 4034 DI 10.1021/jp980420z PG 12 WC Chemistry, Physical SC Chemistry GA ZP698 UT WOS:000073779500027 ER PT J AU Ratsep, M Wu, HM Hayes, JM Blankenship, RE Cogdell, RJ Small, GJ AF Ratsep, M Wu, HM Hayes, JM Blankenship, RE Cogdell, RJ Small, GJ TI Stark hole-burning studies of three photosynthetic complexes SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID LIGHT-HARVESTING COMPLEXES; DIPOLE-MOMENT DIFFERENCES; REACTION CENTERS; PROSTHECOCHLORIS-AESTUARII; ANTENNA COMPLEX; OPTICAL-SPECTRA; ENERGY-TRANSFER; BACTERIOCHLOROPHYLL-PROTEIN; RHODOBACTER-SPHAEROIDES; EFFECT SPECTROSCOPY AB Stark hole-burning spectroscopy at 1.8 K was used to determine the dipole moment changes f Delta mu (f, the local field correction factor) for the B800 absorption band of the light harvesting 2 (LH2) complex of Rhodobacter sphaeroides, Rhodopseudomonas acidophila (strain 10050), and Rhodospirillum molischianum. Hole-burning values of f Delta mu for the lowest energy exciton level (B870) associated with LH2's B850 band have recently been reported (Ratsep et al. Spectrochim. Acta, in press). Values for the lowest energy exciton level (B896) associated with the B875 band of the LH1 complex of Rb. sphaeroides (wild-type chromatophores and an LH1-only mutant) and the 825 nm band of the bacteriochlorophyll a (FMO) antenna complex of Chlorobium tepidum are also reported. For each band, f Delta mu was determined for burn laser polarization parallel and perpendicular to the Stark field E-S and several burn frequencies. The dependencies on laser polarization and burn frequency are typically quite weak. Importantly, f Delta mu values for the above bands are small, falling in the range similar to 0.5-1.2 D, with the lowest and highest values associated with the 825 nm band of the FMO complex and B800 band of the LH2 complex, respectively. For the B896 band of the LH1 complex, f Delta mu approximate to 0.8 D. Such small values are consistent with the very weak linear electron-phonon coupling of antenna protein complexes as determined by hole-burning spectroscopy. Overall, the values for f Delta mu from classical Stark modulation (CSM) studies (Gottfried et al. Biochim. Biophys. Acta 1991, 1059, 63; Beekman et al. J. Phys. Chem. B 1997, 101, 7293) are larger, in the cases of B850 and B875, by a factor of 3-4. (In CSM spectroscopy, one analyzes the response of the entire absorption band to the external field.) Discussion of the discrepancies between the two Stark techniques is given. It appears that difficulties inherent to the analysis procedure of CSM spectroscopy can lead to unreliable values for dipole moment and polarizability changes associated with absorption bands of photosynthetic complexes, especially when several excitonic levels contribute to the band, e.g., B850 and B875. An explanation for the small. hole-burning values of f Delta mu for the B870 and B896 levels associated with C-n cyclic arrays of strongly coupled BChl a dimers is given based on structural, symmetry, and energy disorder considerations. A key point is that, in the absence of energy disorder, the component of Delta mu(j) (j labeling the exciton level) perpendicular to the C-n axis is zero. Energy disorder, which destroys the C-n symmetry and leads to localization effects results in nonzero values which may depend on j when the protein-induced contribution to Delta mu(j) is taken into account. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Arizona State Univ, Ctr Study Early Events Photosynth, Dept Chem & Biochem, Tempe, AZ 85287 USA. Univ Glasgow, Inst Biomed & Life Sci, Div Biochem & Mol Biol, Glasgow G12 8QQ, Lanark, Scotland. RP Small, GJ (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. NR 63 TC 45 Z9 45 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 14 PY 1998 VL 102 IS 20 BP 4035 EP 4044 DI 10.1021/jp980421r PG 10 WC Chemistry, Physical SC Chemistry GA ZP698 UT WOS:000073779500028 ER PT J AU Khan, AA Bhattacharya, T Collins, S Davies, CTH Gupta, R Morningstar, C Shigemitsu, J Sloan, J AF Khan, AA Bhattacharya, T Collins, S Davies, CTH Gupta, R Morningstar, C Shigemitsu, J Sloan, J TI B meson decay constants from NRQCD SO PHYSICS LETTERS B LA English DT Article ID PERTURBATION-THEORY; QCD AB We present quenched results for B meson decay constants using NRQCD b quarks and O(a) tadpole improved clover light quarks. For the first time, one-loop matching factors between lattice and continuum currents are incorporated through O(alpha/M) taking operator mixing fully into account. This includes an important O(alpha a) discretization correction to the heavy-light axial vector current. We find f(B) = 147(11)((+8)(-12))(9)(6) MeV and f(Bs)/f(B) = 1.20(4)((+4)(-0)). (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Kentucky, Dept Phys, Lexington, KY 40506 USA. RP Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. RI Bhattacharya, Tanmoy/J-8956-2013; OI Bhattacharya, Tanmoy/0000-0002-1060-652X; Collins, Sara/0000-0003-0979-7602; Morningstar, Colin/0000-0002-0607-9923 NR 30 TC 45 Z9 45 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 14 PY 1998 VL 427 IS 1-2 BP 132 EP 140 DI 10.1016/S0370-2693(98)00323-2 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 100DB UT WOS:000074798300022 ER PT J AU Dunietz, I AF Dunietz, I TI Clean CKM information from B-d(t)-> D-(*)-/+pi(+/-) SO PHYSICS LETTERS B LA English DT Article ID CP-VIOLATION; ISOSPIN ANALYSIS; B-MESONS; DECAYS; ASYMMETRY AB It has been known for many years that the B-d(tl) --> D-(*-/+) {pi(+/-),rho(+/-),a(1)(+/-)} modes may involve observable CP violating effects. This note describes how to determine cleanly the Cabibbo-Kobayashi-Maskawa (CKM) phase phi = -2 beta - gamma = - pi + alpha - beta, even in the presence of possible final state interactions. A discrete ambiguity remains. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Dunietz, I (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 28 TC 81 Z9 82 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 14 PY 1998 VL 427 IS 1-2 BP 179 EP 182 DI 10.1016/S0370-2693(98)00304-9 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 100DB UT WOS:000074798300028 ER PT J AU Frabetti, PL Cheung, HWK Cumalat, JP Dallapiccola, C Ginkel, JF Johns, SE Nehring, MS Vaandering, EW Butler, JN Cihangir, S Gaines, I Garbincius, PH Garren, L Gourlay, SA Harding, DJ Kasper, P Kreymer, A Lebrun, P Shukla, S Vittone, M Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Culbertson, R Gardner, RW Gottschalk, E Greene, R Park, K Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L Di Corato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Meroni, E Milazzo, L Moroni, L Pedrini, D Perasso, L Prelz, F Sala, A Sala, S Torretta, D Buchholz, D Claes, D Gobbi, B O'Reilly, B Bishop, JM Cason, NM Kennedy, CJ Kim, GN Lin, TF Puseljic, DL Ruchti, RC Shephard, WD Swiatek, JA Wu, ZY Arena, V Boca, G Bonomi, G Castoldi, C Gianini, G Merlo, M Ratti, SP Riccardi, C Viola, L Vitulo, P Lopez, A Mendez, L Mirles, A Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Link, JM Paolone, VS Tager, PM Wilson, JR Cao, J Hosack, M Sheldon, PD Davenport, F Cho, K Danyo, K Handler, T Cheon, BG Chung, YS Kang, JS Kim, KY Lee, KB Myung, SS AF Frabetti, PL Cheung, HWK Cumalat, JP Dallapiccola, C Ginkel, JF Johns, SE Nehring, MS Vaandering, EW Butler, JN Cihangir, S Gaines, I Garbincius, PH Garren, L Gourlay, SA Harding, DJ Kasper, P Kreymer, A Lebrun, P Shukla, S Vittone, M Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Culbertson, R Gardner, RW Gottschalk, E Greene, R Park, K Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L Di Corato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Meroni, E Milazzo, L Moroni, L Pedrini, D Perasso, L Prelz, F Sala, A Sala, S Torretta, D Buchholz, D Claes, D Gobbi, B O'Reilly, B Bishop, JM Cason, NM Kennedy, CJ Kim, GN Lin, TF Puseljic, DL Ruchti, RC Shephard, WD Swiatek, JA Wu, ZY Arena, V Boca, G Bonomi, G Castoldi, C Gianini, G Merlo, M Ratti, SP Riccardi, C Viola, L Vitulo, P Lopez, A Mendez, L Mirles, A Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Link, JM Paolone, VS Tager, PM Wilson, JR Cao, J Hosack, M Sheldon, PD Davenport, F Cho, K Danyo, K Handler, T Cheon, BG Chung, YS Kang, JS Kim, KY Lee, KB Myung, SS CA E687 Collaboration TI A new measurement of the lifetime of the Xi(+)(c) SO PHYSICS LETTERS B LA English DT Article ID XI-C+; BARYON; MASS; DECAYS AB New measurements of the lifetime and mass of the Xi(c)(+) are presented. The Xi(c)(+) has been reconstructed through the two decay channels Xi(-)pi(+)pi(+) Md Sigma(+)K(-)pi(+).. The data were accumulated by;the Fermilab high energy photoproduction experiment E687. The lifetime is measured to be 0.34(-0.05)(+0.07) (stat.) +/- 0.02(syst.) ps while the mass is measured to be 2465.8 +/- 1.9(stat.)+/- 2.5(syst.) MeV/c(2). (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Bologna, Dipartmento Fis, I-40126 Bologna, Italy. INFN, I-40126 Bologna, Italy. Univ Colorado, Boulder, CO 80309 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Illinois, Urbana, IL 61801 USA. Univ Illinois, Urbana, IL 61801 USA. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. INFN, I-20133 Milan, Italy. Northwestern Univ, Evanston, IL 60208 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Univ Pavia, Dipartimento Fis Nucl & Teor, I-27100 Pavia, Italy. INFN, I-27100 Pavia, Italy. Univ Puerto Rico, Mayaguez, PR USA. Univ Calif Davis, Davis, CA 95616 USA. Univ S Carolina, Columbia, SC 29208 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ N Carolina, Asheville, NC 28804 USA. Univ Tennessee, Knoxville, TN 37996 USA. Korea Univ, Seoul 136701, South Korea. RP Frabetti, PL (reprint author), Univ Bologna, Dipartmento Fis, I-40126 Bologna, Italy. RI Bonomi, Germano/G-4236-2010; Link, Jonathan/L-2560-2013 OI Bonomi, Germano/0000-0003-1618-9648; Link, Jonathan/0000-0002-1514-0650 NR 12 TC 9 Z9 9 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 14 PY 1998 VL 427 IS 1-2 BP 211 EP 216 DI 10.1016/S0370-2693(98)00362-1 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 100DB UT WOS:000074798300033 ER PT J AU Allison, WWM Alner, GJ Ayres, DS Barr, G Barrett, WL Bode, C Border, PM Brooks, CB Cobb, JH Cotton, R Courant, H Demuth, DM Fields, TH Gallagher, HR Garcia-Garcia, C Goodman, MC Gran, R Joffe-Minor, T Kafka, T Kasahara, SMS Leeson, W Litchfield, PJ Longley, NP Mann, WA Marshak, ML Milburn, RH Miller, WH Mualem, L Napier, A Oliver, WP Pearce, GF Peterson, EA Petyt, DA Price, LE Ruddick, K Schneps, J Schub, MH Seidlein, R Stassinakis, A Tom, H Thron, JL Vassiliev, V Villaume, G Wakeley, S Wall, D West, N Wielgosz, UM AF Allison, WWM Alner, GJ Ayres, DS Barr, G Barrett, WL Bode, C Border, PM Brooks, CB Cobb, JH Cotton, R Courant, H Demuth, DM Fields, TH Gallagher, HR Garcia-Garcia, C Goodman, MC Gran, R Joffe-Minor, T Kafka, T Kasahara, SMS Leeson, W Litchfield, PJ Longley, NP Mann, WA Marshak, ML Milburn, RH Miller, WH Mualem, L Napier, A Oliver, WP Pearce, GF Peterson, EA Petyt, DA Price, LE Ruddick, K Schneps, J Schub, MH Seidlein, R Stassinakis, A Tom, H Thron, JL Vassiliev, V Villaume, G Wakeley, S Wall, D West, N Wielgosz, UM TI Search for the proton decay mode p ->nu K+ in Soudan 2 SO PHYSICS LETTERS B LA English DT Article ID NUCLEON-DECAY; DETECTOR; NEUTRINO; FLUX AB We have searched for the proton decay mode p --> nu K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu(+)nu or pi(+)pi(0). We found one candidate event consistent with background, yielding a limit, tau/B(p --> nu K+)> 4.3 x 10(31) years at 90% CL with no background subtraction. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Minnesota, Minneapolis, MN 55455 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Tufts Univ, Medford, MA 02155 USA. Western Washington Univ, Bellingham, WA 98225 USA. RP Allison, WWM (reprint author), Univ Oxford, Dept Phys, Oxford OX1 3RH, England. NR 23 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 14 PY 1998 VL 427 IS 1-2 BP 217 EP 224 DI 10.1016/S0370-2693(98)00380-3 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 100DB UT WOS:000074798300034 ER PT J AU Murphy, VJ Rabinovich, D Hascall, T Klooster, WT Koetzle, TF Parkin, G AF Murphy, VJ Rabinovich, D Hascall, T Klooster, WT Koetzle, TF Parkin, G TI False minima in x-ray structure solutions associated with a "partial polar ambiguity": Single crystal x-ray and neutron diffraction studies on the eight-coordinate tungsten hydride complexes, W(PMe3)(4)H2X2 (X=F, Cl, Br, I) and W(PMe3)(4)H2F(FHF) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Review ID ABSOLUTE-STRUCTURE REFINEMENT; SPACE-GROUP CHANGES; MOLECULAR-STRUCTURE; OXIDATIVE ADDITION; SOLID-STATE; TRIMETHYLPHOSPHINE COMPLEXES; MOLYBDENUM(II) COMPLEXES; CRYSTALLOGRAPHIC DATA; METAL-COMPLEXES; HYDROGEN-BOND AB The molecular structures of the eight-coordinate tungsten hydride complexes W(PMe3)(4)H2X2 (X = F, Cl, Br, I) and W(PMe3)(4)H2F(FHF) have been determined by single-crystal X-ray diffraction; W(PMe3)(4)H2Cl2 and W(PMe3)(4)H2F(FHF) have also been analyzed by single-crystal neutron diffraction, thereby accurately locating the positions of the hydride ligands. The structures of all of these complexes are similar and are based on a trigonal dodecahedron, with a distorted tetrahedral array of PMe3 ligands in which two of the PMe3 ligands are displaced over the halide substituents. However, the initial structures derived for both W(PMe3)(4)H2Cl2 and W(PMe3)(4)H2F(FHF) did nos exhibit the aforementioned geometry, but were based on an arrangement in which the two transoid-PMe3 ligands are displaced toward the two cis-PMe3 groups, rather than tilted toward the chloride ligands. Interestingly, the unexpected structures for W(PMe3)(4)H2Cl2 and W(PMe3)(4)H2F(FHF) were discovered to be the result of an artifact due to the presence of a heavy atom in a polar space group, which allowed the X-ray structure solutions to refine into most deceptive false minima. Specifically, for the structures corresponding to the false minima, the transoid-PMe3 ligands were incorrectly located in positions that are related to their true locations by reflection perpendicular to the polar axis. In effect, the incorrect molecular structures are a composite of the two possible true polar configurations which are related by a reflection perpendicular to the polar axis, i.e. a "partial polar ambiguity". Of most importance, the solutions corresponding to the false minima are characterized by low R values and well-behaved displacement parameters, so that it is not apparent that the derived structures are incorrect. Thus, for space groups with a polar axis, it is necessary to establish that all of the atoms in the asymmetric unit belong to a single true polar configuration. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Columbia Univ, Dept Chem, New York, NY 10027 USA. RP Koetzle, TF (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 171 TC 48 Z9 48 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 13 PY 1998 VL 120 IS 18 BP 4372 EP 4387 DI 10.1021/ja974086g PG 16 WC Chemistry, Multidisciplinary SC Chemistry GA ZN435 UT WOS:000073645600015 ER PT J AU Tokuhisa, H Zhao, MQ Baker, LA Phan, VT Dermody, DL Garcia, ME Peez, RF Crooks, RM Mayer, TM AF Tokuhisa, H Zhao, MQ Baker, LA Phan, VT Dermody, DL Garcia, ME Peez, RF Crooks, RM Mayer, TM TI Preparation and characterization of dendrimer monolayers and dendrimer-alkanethiol mixed monolayers adsorbed to gold SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SURFACE-CONFINED MONOLAYERS; PHASE PROBE MOLECULES; SELF-ASSEMBLED MONOLAYERS; ORGANIC-SURFACES; ELECTRODES; FILMS; SPECTROSCOPY; ADSORPTION; ARCHITECTURE; WETTABILITY AB Single-component monolayers of dendrimers and two-component monolayers consisting of dendrimers and n-alkanethiols immobilized on Au substrates are described. Single-component monolayers are prepared by exposing an Au substrate to ethanolic solutions of amine-or hydroxy-terminated polyamidoamine (PAMAM) dendrimers. The resulting monolayers are highly stable and nearly close-packed for dendrimer generations ranging from 4 to 8 (G4-G8). Electrochemical ac-impedance measurements indicate that the dendrimer surface is very porous toward the electroactive redox couple Fe(CN)(6)(3-/4-). Ferrocene-terminated dendrimer monolayers have also been investigated. Exposure of higher-generation dendrimer monolayers to ethanolic solutions of hexadecanethiol (C16SH) results in a dramatic compression of the dendrimers, and causes them to reorient on the surface from an oblate to prolate configuration. The dendrimers originally present on the surface do not desorb as a consequence of this configurational change. Comparison of the extent of adsorption of C16SH in different media (vapor-phase N-2, hexane, and ethanol) shows that solvation of the dendrimers is the primary driving force for the structural change. Finally, the reactivity and stability of the dendrimer monolayers is investigated by on-surface functionalization of the dendrimer monolayer with 4-(trifluoromethyl)benzoyl chloride. The physical and chemical properties of the single- and two-component monolayers are evaluated by using reflection infrared spectroscopy, ellipsometry, contact-angle measurements, ac-impedance spectroscopy, cyclic voltammetry, and surface acoustic wave (SAW)-based analyte-dosing experiments. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Crooks, RM (reprint author), Texas A&M Univ, Dept Chem, POB 300012, College Stn, TX 77842 USA. RI Baker, Lane/B-6452-2008 NR 67 TC 215 Z9 219 U1 5 U2 48 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 13 PY 1998 VL 120 IS 18 BP 4492 EP 4501 DI 10.1021/ja9742904 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA ZN435 UT WOS:000073645600029 ER PT J AU George, GN Garrett, RM Graf, T Prince, RC Rajagopalan, KV AF George, GN Garrett, RM Graf, T Prince, RC Rajagopalan, KV TI Interaction of arsenate with the molybdenum site of sulfite oxidase SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-PARAMAGNETIC-RESONANCE; RAY-ABSORPTION-SPECTROSCOPY; XANTHINE-OXIDASE; FINE-STRUCTURE; CHICKEN LIVER; CYSTEINE-207; PHOSPHATE; KINETICS; MO(V) C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Duke Univ, Dept Biochem, Durham, NC 27710 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP George, GN (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, POB 4349,MS 69, Stanford, CA 94309 USA. RI George, Graham/E-3290-2013 NR 31 TC 32 Z9 32 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 13 PY 1998 VL 120 IS 18 BP 4522 EP 4523 DI 10.1021/ja973473n PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZN435 UT WOS:000073645600035 ER PT J AU Nienhaus, GU Chu, K Jesse, K AF Nienhaus, GU Chu, K Jesse, K TI Structural heterogeneity and ligand binding in carbonmonoxy myoglobin crystals at cryogenic temperatures SO BIOCHEMISTRY LA English DT Article ID HEME-PROTEINS; MOLECULAR-DYNAMICS; THERMAL RELAXATION; FECO UNIT; MONOXIDE; DISTAL; PHOTODISSOCIATION; PHOTOLYSIS; MODELS; LIGHT AB We have characterized the ligand-rebinding behavior of single crystal native sperm whale carbonmonoxy myoglobin (swMbCO) (space group P2(1)) and a synthetic mutant swMbCO (space group P6) at cryogenic temperatures by using temperature-derivative spectroscopy (TDS) with monitoring of the CO stretch bands in the mid-infrared. Crystals were studied at pH 5.1 and 7.0 for native swMbCO and at pH 7.0 for the mutant; both short-flash and extended illumination protocols were performed. The TDS analysis yields the enthalpy barrier distributions for recombination in the individual taxonomic (A) substates, A(0), A(1), and A(3). A single gaussian barrier distribution gave a good first-order description but was insufficient to precisely fit the data within each substate. An additional minority species was necessary to model the enhanced rebinding below 30 K, which likely appears because of quantum tunneling. The peak positions and widths of the enthalpy distributions are similar for the P2(1) and P6 crystal forms, indicating that crystal-packing forces have only very minor effects on the structure at the active site. Moreover, the widths of the (dominant) distributions are qualitatively similar to those observed with glycerol-water solutions, which shows that the degree of structural heterogeneity is similar for solution and crystalline samples. For the A(3) substate, a significantly lower peak enthalpy was obtained (by similar to 4 kJ/mol) than for solutions, while the peak shifts in the A(0) and A(1) substates were small. In samples cooled under illumination, discrete populations with higher rebinding barriers were observed. Concomitant changes in the stretch absorption of the photodissociated CO (B states) only occur between 100 and 130 K. They likely arise from movements of the ligand in the heme pocket between discrete sites. C1 Univ Ulm, Dept Biophys, D-89069 Ulm, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nienhaus, GU (reprint author), Univ Ulm, Dept Biophys, D-89069 Ulm, Germany. RI Nienhaus, Gerd Ulrich/G-8698-2012 OI Nienhaus, Gerd Ulrich/0000-0002-5027-3192 FU NIGMS NIH HHS [GM 18051] NR 30 TC 26 Z9 26 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 12 PY 1998 VL 37 IS 19 BP 6819 EP 6823 DI 10.1021/bi972843h PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZP874 UT WOS:000073797300023 PM 9578567 ER PT J AU Samuel, J Brinker, CJ Frink, LJD van Swol, F AF Samuel, J Brinker, CJ Frink, LJD van Swol, F TI Direct measurement of solvation forces in complex microporous media: A new characterization tool SO LANGMUIR LA English DT Article ID DENSITY-FUNCTIONAL THEORY; FLUID-WALL INTERFACE; COMPUTER-SIMULATION; DRYING TRANSITIONS; MEMBRANES; SURFACES AB We present a new beam bending (BB) technique for measuring solvation forces in complex microporous materials. The solvation forces are compressive and monotonically increasing with relative pressure. This is in stark contrast to Laplace-Kelvin theory (LKT) which predicts only tensile stresses. Applying a nonlocal density functional theory (DFT), the observed monotonic, compressive stresses are shown to arise from molecular sized pores with modest pore size polydispersity where the half-width of the distribution is 0.2-0.7 nm. Finally, the combined BB/DFT analysis provides a novel and much needed method for characterizing the morphology of microporous thin film materials to 0.1 nm resolution. C1 Satec Ecochem, IL-91450 Jerusalem, Israel. Sandia Natl Labs, Direct Fabricat Dept, Albuquerque, NM 87185 USA. Univ New Mexico, NSF, Ctr Microengn Mat, Albuquerque, NM 87131 USA. Sandia Natl Labs, Computat Mat Sci Dept 9225, Albuquerque, NM 87185 USA. Sandia Natl Labs, Theoret & Computat Mat Modeling Dept 1841, Albuquerque, NM 87185 USA. RP Frink, LJD (reprint author), Satec Ecochem, POB 45022, IL-91450 Jerusalem, Israel. NR 20 TC 15 Z9 15 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 12 PY 1998 VL 14 IS 10 BP 2602 EP 2605 DI 10.1021/la980073k PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZN287 UT WOS:000073630800005 ER PT J AU Nooney, MG Campbell, A Murrell, TS Lin, XF Hossner, LR Chusuei, CC Goodman, DW AF Nooney, MG Campbell, A Murrell, TS Lin, XF Hossner, LR Chusuei, CC Goodman, DW TI Nucleation and growth of phosphate on metal oxide thin films SO LANGMUIR LA English DT Article ID ANION-ADSORPTION; ULTRAHIGH-VACUUM; IRON-OXIDES; GOETHITE; SPECTROSCOPY; MORPHOLOGY; CHARGE; SYSTEM; SOILS AB The kinetics of phosphate uptake by hematite, titania, and alumina were examined by exposing freshly prepared thin films to phosphate solutions at incremental times and subsequently analyzing the surfaces by Auger electron spectroscopy (AES), temperature programmed desorption (TPD), and atomic force microscopy (AFM). Thin film hematite exposed to a sodium phosphate solution demonstrated initially rapid phosphate chemisorption during the first 10 min of solution exposure, followed by island growth. For titania and alumina exposed to a calcium phosphate solution, the initially rapid reaction was completed after 1 and 3 h, respectively. Subsequent rapid three-dimensional growth occurred after 3-4 h for titania and 25-30 h for alumina. The trend in the rate of formation of phosphate film on titania and alumina was comparable to those of in-situ studies using the same solutions. AFM data on the 10-20-mu m scale did not show distinct changes between clean and phosphate-covered alumina and iron oxide surfaces; however, structures 200-500 nm in diameter could be observed on these surfaces after exposure to phosphate solution. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. Pacific NW Lab, Richland, WA 99352 USA. Texas A&M Univ, Dept Soil & Crop Sci, College Stn, TX 77843 USA. RP Goodman, DW (reprint author), Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. NR 29 TC 35 Z9 35 U1 2 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 12 PY 1998 VL 14 IS 10 BP 2750 EP 2755 DI 10.1021/la9702695 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZN287 UT WOS:000073630800025 ER PT J AU Gidalevitz, D Mindyuk, OY Heiney, PA Ocko, BM Kurnaz, ML Schwartz, DK AF Gidalevitz, D Mindyuk, OY Heiney, PA Ocko, BM Kurnaz, ML Schwartz, DK TI Thermal melting in Langmuir films of discotic liquid-crystalline compounds SO LANGMUIR LA English DT Article ID AIR-WATER-INTERFACE; MONOLAYERS; SURFACE; MOLECULES; GROWTH AB We have studied the thermal melting of two disk-shaped molecules at the air-water interface. Brewster angle microscopy images of both compounds indicated first order phase transitions from a low-temperature solid phase to a high-temperature fluid phase. The high-temperature phase could be either isotropic or nematic. Grazing-incidence diffraction measurements provided corroborating evidence of reversible melting, in the form of Bragg peaks that vanished at high temperature and reappeared upon cooling. Furthermore, we observed that the diffraction peaks obtained upon recooling were substantially sharper than those obtained initially, and the domain sizes seen in Brewster angle microscopy were substantially larger, indicating an enhancement of crystalline domain size by thermal annealing. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Tulane Univ, Dept Chem, New Orleans, LA 70118 USA. RP Heiney, PA (reprint author), Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. RI Kurnaz, Levent/B-8925-2008; Gidalevitz, David/D-6717-2012; Schwartz, Daniel/H-5153-2012 NR 33 TC 17 Z9 17 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 12 PY 1998 VL 14 IS 10 BP 2910 EP 2915 DI 10.1021/la971287p PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZN287 UT WOS:000073630800048 ER PT J AU Ryan, TJ Semlitsch, RD AF Ryan, TJ Semlitsch, RD TI Intraspecific heterochrony and life history evolution: Decoupling somatic and sexual development in a facultatively paedomorphic salamander SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID AMBYSTOMA-TALPOIDEUM; TIGER SALAMANDER; PEDOMORPHOSIS; COMPLEX; SIZE; ONTOGENY; DENSITY; ARRIVAL; TIME AB Morphological features such as size and shape are the most common focus in studies of heterochronic change. Frequently, these easily observed and measured features are treated as a major target of selection, potentially ignoring traits more closely related to fitness. We question the primacy of morphological data in studies of heterochrony, and instead suggest that principal sources of fitness, such as life history characteristics, are not only the chief targets of selection, but changes in them may necessitate changes in other (subordinate) elements of the organism. We use an experimental approach to investigate the timing of metamorphosis and maturation in a facultatively paedomorphic salamander, Ambystoma talpoideum. We determine that individuals possessing the well-known paedomorphic phenotype are peramorphic with regard to maturation, through the process of predisplacement (an earlier onset of maturation). Combining the well studied ecology of dimorphic A. talpoideum populations with theories of heterochronic mechanisms and life history evolution, we conclude that age at maturation is the principal target of selection and that morphological changes are secondary effects. Increased attention to the intimate connection between life history evolution and heterochrony is the most promising route to a better understanding of both. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Missouri, Div Biol Sci, Columbia, MO 65211 USA. RP Ryan, TJ (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. OI Semlitsch, Raymond/0000-0002-7999-5762 NR 47 TC 57 Z9 59 U1 1 U2 11 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 12 PY 1998 VL 95 IS 10 BP 5643 EP 5648 DI 10.1073/pnas.95.10.5643 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZM977 UT WOS:000073595500043 PM 9576937 ER PT J AU Li, H Hohl, A Gavrielides, A Hou, H Choquette, KD AF Li, H Hohl, A Gavrielides, A Hou, H Choquette, KD TI Stable polarization self-modulation in vertical-cavity surface-emitting lasers SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR-LASERS; DYNAMICS AB The characteristics of polarization self-modulation in a vertical-cavity surface-emitting laser (VCSEL) were studied for frequencies up to approximate to 9 GHz both experimentally and theoretically. Polarization self-modulation was obtained by rotating the linearly polarized output of the VCSEL by 90 degrees and reinjecting it into the laser. Experimentally we simultaneously recorded time traces, optical and radio-frequency spectra. We found for increasing modulation frequencies that the output characteristics changed from square-wave to sinusoidal and the VCSEL system assumed new polarization eigenstates that are different from the free-running VCSEL eigenstates. We modeled polarization self-modulation as an interband process and found a good qualitative agreement between our experimental and numerical results. (C) 1998 American Institute of Physics. [S0003-6951(98)01019-5]. C1 USAF, Res Lab DELO, Nonlinear Opt Grp, Kirtland AFB, NM 87117 USA. Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, Albuquerque, NM 87185 USA. Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87131 USA. RP USAF, Res Lab DELO, Nonlinear Opt Grp, Phillips Res Site,3550 Aberdeen Ave, Kirtland AFB, NM 87117 USA. EM huali@chtm.unm.edu NR 9 TC 73 Z9 73 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 11 PY 1998 VL 72 IS 19 BP 2355 EP 2357 DI 10.1063/1.121398 PG 3 WC Physics, Applied SC Physics GA ZM442 UT WOS:000073540600001 ER PT J AU Demos, SG Yan, M Staggs, M De Yoreo, JJ Radousky, HB AF Demos, SG Yan, M Staggs, M De Yoreo, JJ Radousky, HB TI Raman scattering investigation of KH2PO4 subsequent to high fluence laser irradiation SO APPLIED PHYSICS LETTERS LA English DT Article ID POTASSIUM DIHYDROGEN PHOSPHATE; DAMAGE; SURFACE AB The spectral characteristics of the internal (PO4 tetrahedron) modes of fast-grown KH2PO4 crystals under sub-damage threshold, 10 ns, 355 nm laser irradiation have been investigated. Pump-and-probe Raman spectroscopy indicates transient changes of the intensity of the 915 cm(-1), -PO4 internal mode. This change is attributed to a transient increase of the absorption due to generation by the 355 nm pump pulse of electronic defects in the bulk of the crystal. (C) 1998 American Institute of Physics. [S0003-6951(98)01819-1]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94580 USA. RP Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94580 USA. EM Demos1@llnl.gov NR 15 TC 38 Z9 43 U1 1 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 11 PY 1998 VL 72 IS 19 BP 2367 EP 2369 DI 10.1063/1.121389 PG 3 WC Physics, Applied SC Physics GA ZM442 UT WOS:000073540600005 ER PT J AU Temelkuran, B Ozbay, E Kavanaugh, JP Tuttle, G Ho, KM AF Temelkuran, B Ozbay, E Kavanaugh, JP Tuttle, G Ho, KM TI Resonant cavity enhanced detectors embedded in photonic crystals SO APPLIED PHYSICS LETTERS LA English DT Article ID GAP AB We report a resonant cavity enhanced (RCE) detector built around a three-dimensional photonic band gap crystal, The RCE detector was built by placing a monopole antenna within the localized modes of planar and boxlike defect structures. The enhanced electric field around these defect structures were then measured by a microwave detector and a network analyzer. We measured a power enhancement factor of 3450 for planar cavity structures. A Fabry-Perot cavity model was used to understand and predict resonant cavity enhancement in this structure. The tuning bandwidth of the RCE detector extends from 10.5 to 12.8 GHz. which corresponds to the full photonic band gap by the crystal. These RCE detectors have increased sensitivity and efficiency when compared to conventional detectors, and can be used for various applications. (C) 1998 American Institute of Physics. [S0003-6951(98)02219-0]. C1 Bilkent Univ, Dept Phys, TR-06533 Bilkent, Turkey. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Microelect Res Ctr, Ames, IA 50011 USA. RP Bilkent Univ, Dept Phys, TR-06533 Bilkent, Turkey. EM burak@fen.bilkent.edu.tr RI Ozbay, Ekmel/B-9495-2008 NR 16 TC 49 Z9 50 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 11 PY 1998 VL 72 IS 19 BP 2376 EP 2378 DI 10.1063/1.121361 PG 3 WC Physics, Applied SC Physics GA ZM442 UT WOS:000073540600008 ER PT J AU Colombi, SP Szapudi, I Szalay, AS AF Colombi, SP Szapudi, I Szalay, AS TI Effects of sampling on statistics of large-scale structure SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods, numerical; methods, statistical; galaxies, clusters, general; large-scale structure of Universe ID HIGHER-ORDER STATISTICS; GALAXY REDSHIFT SURVEY; DARK MATTER UNIVERSE; LUMINOSITY FUNCTION; IRAS GALAXIES; COSMOLOGICAL SIMULATIONS; CLUSTER CORRELATIONS; COUNT PROBABILITIES; POWER-SPECTRUM; CFA AB The effects of sampling are investigated on measurements of counts-in-cells in three-dimensional magnitude-limited galaxy surveys, with emphasis on moments of the underlying smooth galaxy density field convolved with a spherical window. A new estimator is proposed for measuring the kth-order moment [rho(k)]: the weighted factorial moment (F) over tilde(k)[omega] Since these statistics are corrected for the effects of the varying selection function, they can extract the moments in one pass without the need to construct a series of volume-limited samples. The cosmic error on the measurement of (F) over tilde(k)[omega] is computed via the formalism of Szapudi & Colombi, which is generalized to include the effects of the selection function. The integral equation for finding the minimum variance weight is solved numerically, and an accurate and intuitive analytical approximation is derived, omega(optimal)(r) proportional to 1/Delta(r), where Delta(r) is the cosmic error as a function of the distance from the observer. The resulting estimator is more accurate than the traditional method of counts-in-cells in volume-limited samples, which discards useful information. As a practical example, it is demonstrated that, unless unforeseen systematics prevent it, the proposed method will extract moments of the galaxy distribution in the future Sloan Digital Sky Survey (hereafter SDSS) with accuracy of order a few per cent for k = 2, 3 and better than 10 per cent for k = 4 in the scale range of 1 less than or equal to l less than or equal to 50 h(-1) Mpc. In the particular case of the SDSS, a homogeneous (spatial) weight omega = 1 is reasonably close to optimal. Optimal sampling strategies for designing magnitude-limited redshift surveys are investigated as well. The arguments of Kaiser are extended to higher order moments, and it is found that the optimal strategy depends greatly on the statistics and scales considered. A sampling rate f similar to 1/3 - 1/10 is appropriate to measure low-order moments with k less than or equal to 4 in the scale range 1 less than or similar to l less than or similar to 50 h(-1) Mpc. However, the optimal sampling rate increases with the order considered, k, and with 1/l. Therefore counts-in-cells statistics in general, such as the shape of the distribution function, high-order moments, cluster selection, etc., require full sampling, especially at small, highly non-linear scales l similar to 1 h(-1) Mpc. Another design issue is the optimal geometry of a catalogue, when it covers only a small fraction of the sky. Similarly to Kaiser, we find that a survey composed of several compact subsamples of angular size Omega(F) spread over the sky on a glass-like structure would do better, with regards to the cosmic error, than the compact or the traditional slice-like configurations, at least at small scales. The required dynamic range of the measurements determines the characteristic size of the subsamples, It is, however, difficult to estimate, since an accurate and cumbersome calculation of edge effects would be required at scales comparable to the size of a subsample. C1 CITA, Toronto, ON M5S 1A7, Canada. CNRS, Inst Astrophys Paris, F-75014 Paris, France. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Colombi, SP (reprint author), CITA, 60 St George St, Toronto, ON M5S 1A7, Canada. NR 82 TC 36 Z9 36 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 11 PY 1998 VL 296 IS 2 BP 253 EP 274 DI 10.1046/j.1365-8711.1998.01291.x PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZP996 UT WOS:000073810600004 ER PT J AU Lebedev, VA Bickley, M Schaffner, S van Zeijts, J Krafft, GA Watson, WA AF Lebedev, VA Bickley, M Schaffner, S van Zeijts, J Krafft, GA Watson, WA TI Correction of dispersion and the betatron functions in the CEBAF accelerator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB During commissioning of the CEBAF accelerator, correcting dispersion, momentum compaction and betatron beam envelopes was essential for robust operation. To speed up the diagnostic process we developed a method which allows one to track and correct the machine optics on-line. The method is based on measuring the propagation of 30 Hz modulated batatron oscillations. Compared to the usual methods of dispersion or difference orbit measurement, synchronous detection of the beam displacement, as measured by beam position monitors, offers significantly improved speed and accuracy. The beam optics of the accelerator was altered to decrease lattice sensitivity at critical points and to simplify control of the betatron function match. The calculation of the Courant-Snyder invariant from signals of each pair of beam position monitors was used for a correction of the betatron functions. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Lebedev, VA (reprint author), Thomas Jefferson Natl Accelerator Facil, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 373 EP 379 DI 10.1016/S0168-9002(98)00198-3 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500003 ER PT J AU Akchurin, N Ayan, S Bencze, GL Chikin, K Cohn, H Doulas, S Dumanoglu, I Eskut, E Fenyvesi, A Ferrando, A Fouz, MC Ganel, O Gavrilov, V Gershtein, Y Hajdu, C Iosifidis, J Josa, MI Kayis, A Khan, A Kim, SB Kolosov, V Kuleshov, S Kuzucu-Polatoz, A Langland, J Litvintsev, D Merlo, JP Molnar, J Nikitin, A Onel, Y Onengut, G Osborne, D Ozdes-Koca, N Ozturk, H Penzo, A Pesen, E Podrasky, V Rosowsky, A Salicio, JM Sanzeni, C Sever, R Silvestri, H Stolin, V Sulak, L Sullivan, J Ulyanov, A Uzunian, S Vesztergombi, G Wigmans, R Winn, D Winsor, R Yumashev, A Zalan, P Zeyrek, M AF Akchurin, N Ayan, S Bencze, GL Chikin, K Cohn, H Doulas, S Dumanoglu, I Eskut, E Fenyvesi, A Ferrando, A Fouz, MC Ganel, O Gavrilov, V Gershtein, Y Hajdu, C Iosifidis, J Josa, MI Kayis, A Khan, A Kim, SB Kolosov, V Kuleshov, S Kuzucu-Polatoz, A Langland, J Litvintsev, D Merlo, JP Molnar, J Nikitin, A Onel, Y Onengut, G Osborne, D Ozdes-Koca, N Ozturk, H Penzo, A Pesen, E Podrasky, V Rosowsky, A Salicio, JM Sanzeni, C Sever, R Silvestri, H Stolin, V Sulak, L Sullivan, J Ulyanov, A Uzunian, S Vesztergombi, G Wigmans, R Winn, D Winsor, R Yumashev, A Zalan, P Zeyrek, M TI On the differences between high-energy proton and pion showers and their signals in a non-compensating calorimeter SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We present the results of experimental studies of hadron showers in a copper:quartz-fiber calorimeter, based on the detection of Cherenkov light. These studies show that there are very significant differences between the signals from protons and pions at the same energies. In the energy range between 200 and 375 GeV, where these studies were performed, the calorimeter's response to protons was typically 10% smaller than the response to pions. On the other hand, the energy resolution was about 25% better for protons. In addition, the protons had a Gaussian line shape, whereas the pion response curve was asymmetric. These differences can be understood from the requirements of baryon number conservation in the shower development. They are expected to be present in any non-compensating calorimeter, to a degree determined by the e/h value. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Texas Tech Univ, Dept Phys, Lubbock, TX 79409 USA. Univ Iowa, Iowa City, IA USA. Middle E Tech Univ, TR-06531 Ankara, Turkey. KFKI, RMKI, Budapest, Hungary. Moscow State Univ, NPI, Moscow, Russia. Oak Ridge Natl Lab, Oak Ridge, TN USA. Boston Univ, Boston, MA 02215 USA. Cukurova Univ, Adana, Turkey. ATOMKI, Debrecen, Hungary. CIEMAT, E-28040 Madrid, Spain. ITEP, Moscow, Russia. Fairfield Univ, Fairfield, CT 06430 USA. Univ Trieste, Trieste, Italy. Ist Nazl Fis Nucl, Sez Trieste, Trieste, Italy. RP Wigmans, R (reprint author), Texas Tech Univ, Dept Phys, Box 41051, Lubbock, TX 79409 USA. RI Kuleshov, Sergey/D-9940-2013; Kim, Soo-Bong/B-7061-2014; Josa, Isabel/K-5184-2014; Pesen, Erhan/B-1753-2017; OI Kuleshov, Sergey/0000-0002-3065-326X; Uliyanov, Alexey/0000-0001-6935-8949 NR 8 TC 29 Z9 29 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 380 EP 396 DI 10.1016/S0168-9002(98)00021-7 PG 17 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500004 ER PT J AU Lacasse, R Barrette, J Dai, Y Filimonov, K Gilbert, S Mark, SK Pruneau, C Rosati, M Qi, YJ Starinsky, N Wang, G Sedykh, S Woody, CL AF Lacasse, R Barrette, J Dai, Y Filimonov, K Gilbert, S Mark, SK Pruneau, C Rosati, M Qi, YJ Starinsky, N Wang, G Sedykh, S Woody, CL TI A time-of-flight hodoscope for the E877 spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID COLLISIONS; COUNTERS AB The design and performance of the main time-of-flight hodoscope used in the E877 spectrometer at the BNL-AGS are presented. The hodoscope covers an area of 0.70 x 2.00 m(2). It is made of 150 scintillator counters viewed by phototubes at each end. The detectors are mounted in an are and arranged to eliminate gaps between the counters. An average time resolution of 85 ps has been measured over the entire hodoscope. (C) 1998 Elsevier Science B.V. All rights reserved. C1 McGill Univ, Dept Phys, Montreal, PQ, Canada. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Iowa State Univ, Ames, IA 50011 USA. Wayne State Univ, Detroit, MI 48202 USA. RP Barrette, J (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ, Canada. NR 10 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 408 EP 424 DI 10.1016/S0168-9002(98)00170-3 PG 17 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500006 ER PT J AU Kohnle, A Smither, R Graber, T von Ballmoos, P Laporte, P Olive, JF AF Kohnle, A Smither, R Graber, T von Ballmoos, P Laporte, P Olive, JF TI Realization of a tunable crystal lens as an instrument to focus gamma rays SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ANNIHILATION-RADIATION TELESCOPE; DIFFRACTION AB The Argonne/Toulouse collaboration is developing a crystal lens diffraction telescope for use as an astrophysical detector in the energy range of 200 keV to 1.3 MeV. The lens consists of eight rings of diffraction crystals that all focus a narrow band of energies on a common HPGe detector. The inclination angle of these crystals controls the energy band being focused and will need to be adjusted over a range of 0.5-1.5 degrees with arcsecond precision to cover this energy band. At Argonne National Laboratory, a new lens frame was constructed, and the inner ring was equipped with 16 Ge crystals of 1 cm(3) size. The orientation of each crystal was adjusted using a piezo-based picomotor in combination with a noncontact eddy-current sensor. The sensors have 0.1-0.2 arcsecond resolution; the motors have a step size of 0.05-0.2 arcseconds. By changing the crystal inclination and the distance of the detector from the lens, we were able to focus the 662 keV radiation from a Cs-137 source at 24.75 m, as well as line energies at 276, 303, 356, and 383 keV from a Ba-133 source at 24.45 m. The sensor and system stability were demonstrated by alternately focusing different line energies. We were able to simulate scans in energy of a spaceborne instrument, as well as the enlargening of the energy response by a slight detuning of the lens crystals. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Ctr Etud Spatiale Rayonnements, F-31029 Toulouse, France. Argonne Natl Lab, Argonne, IL 60439 USA. RP Ctr Etud Spatiale Rayonnements, 9 Av Colonel Roche, F-31029 Toulouse, France. EM kohnle@cesr.cnes.fr OI Kohnle, Antje/0000-0003-2638-4826 NR 5 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 553 EP 561 DI 10.1016/S0168-9002(98)00148-X PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500021 ER PT J AU Reeder, PL Bowyer, TW AF Reeder, PL Bowyer, TW TI Delayed coincidence technique for Xe-133g detection SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Delayed coincidence techniques show promise of significant improvements for a Xe counting system which will be a key element in monitoring the Comprehensive Test Ban Treaty. We have previously developed a beta-gamma counting system for Xe-131m, Xe-133m, Xe-133g, and Xe-135g as part of an automated system for analyzing Xe in air. Depending on background levels, higher sensitivity for Xe-133g can be achieved by use of the delayed coincidence between beta particles that feed the 81 keV state in Cs-133 and the conversion electrons produced in the deexcitation of the 81 keV state (t(1/2) = 6.36 ns). In the delay rime region, only the 31 keV X-ray associated with Xe-133g decay is observed. This technique detects Xe-133g With extremely low background and distinguishes Xe-133g from Xe-131m and Xe-133m. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Reeder, PL (reprint author), Pacific NW Lab, MS P8-08,POB 999, Richland, WA 99352 USA. NR 6 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 573 EP 581 DI 10.1016/S0168-9002(98)00213-7 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500023 ER PT J AU Reeder, PL Bowyer, TW AF Reeder, PL Bowyer, TW TI Xe isotope detection and discrimination using beta spectroscopy with coincident gamma spectroscopy SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Beta spectroscopic techniques show promise of significant improvements for a beta-gamma coincidence counter that is part of a system for analyzing Xe automatically separated from air. The previously developed counting system for Xe-131m, Xe-133m, Xe-133g, and Xe-135g can be enhanced to give additional discrimination between these Xe isotopes by using the plastic scintillation sample cell as a beta spectrometer to resolve the conversion electron peaks. The automated system will be a key factor in monitoring the Comprehensive Test Ban Treaty. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Reeder, PL (reprint author), Pacific NW Lab, MS P8-08,POB 999, Richland, WA 99352 USA. NR 4 TC 25 Z9 25 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 582 EP 590 DI 10.1016/S0168-9002(98)00212-5 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500024 ER PT J AU Coester, F Dannbom, K Riska, DO AF Coester, F Dannbom, K Riska, DO TI Covariant quark model for the baryons SO NUCLEAR PHYSICS A LA English DT Article ID SCATTERING AB A family of simply solvable covariant quark models for the baryons is presented. With optimal parameter choices the models reproduce the empirical spectra of the baryons in all flavor sectors to an accuracy of a few percent. Complete spectra are obtained for all states of the strange, charm and beauty hyperons with L less than or equal to 2, The magnetic moments and axial coupling constants of the ground state baryons correspond to those of conventional quark models. We construct current-density operators that are consistent with empirical nucleon form factors at low and medium momenta. (C) 1998 Elsevier Science B.V. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Helsinki, Dept Phys, Helsinki 00014, Finland. RP Coester, F (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 22 TC 23 Z9 23 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD MAY 11 PY 1998 VL 634 IS 3 BP 335 EP 367 DI 10.1016/S0375-9474(98)00142-0 PG 33 WC Physics, Nuclear SC Physics GA ZX171 UT WOS:000074486500005 ER PT J AU Laska, JE Kaszynski, P Jacobs, SJ AF Laska, JE Kaszynski, P Jacobs, SJ TI Synthesis, strain, conformational analysis, and molecular and crystal structures of 1,1,4,4-tetraphenyl-1,4-disilacyclohexane and 1,1,4,4-tetraphenyl-1,4-disilacyclohexa-2,5-diene SO ORGANOMETALLICS LA English DT Article ID HETERO-PI-SYSTEMS; CATALYZED REACTIONS; 1,4-DISILACYCLOHEXA-2,5-DIENES AB Hydrogenation of 1,1,4,4-tetraphenyl-1,4-disilacyclohexa-2,5-diene (2) to 1,1,4,4-tetraphenyl-1,4-disilacyclohexane (1) provides an efficient new route to 1,4-disilacyclohexanes with isolated overall yields 10 times higher than previously available syntheses. Molecular and crystal structures of 1 and 2 determined by single-crystal X-ray diffraction show that the saturated compound 1 adopts the ideal chairlike conformation, while the unsaturated analogue 2 has a planar 1,4-disilacyclohexa-2,5-diene ring. Ab initio geometry optimizations and vibrational frequency calculations at the 3-21G*/SCF level of theory confirm that the orientations of the phenyl rings observed in 1 represents the global minimum on the potential-energy surface. Calculations of the transition state for the phenyl ring rotations in 1 reveal a barrier height of Delta G double dagger = 4.09 kcal/mol. Energy profiles of chairlike and boatlike distortions of 1,4-disilacyclohexa-2,5-diene (12) were calculated and compared with the observed deviation from planarity in other derivatives of 12. Calculation of ring strain energies revealed that diene 12 and its saturated analogue 1,4-disilacyclohexane (4) are almost strain free (1.2 and 0.7 kcal/mol, respectively), resembling their carbon analogues. C1 Vanderbilt Univ, Dept Chem, Organ Mat Res Grp, Nashville, TN 37235 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kaszynski, P (reprint author), Vanderbilt Univ, Dept Chem, Organ Mat Res Grp, Box 1583, Nashville, TN 37235 USA. NR 43 TC 3 Z9 3 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD MAY 11 PY 1998 VL 17 IS 10 BP 2018 EP 2026 DI 10.1021/om9707883 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA ZP802 UT WOS:000073789900021 ER PT J AU Horowitz, GT Ooguri, H AF Horowitz, GT Ooguri, H TI Spectrum of large N gauge theory from supergravity SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM FIELD-THEORY; SPACE AB Recently, Maldacena proposed that the large N limit of the N = 4 supersymmetric gauge theory in four dimensions with U(N) gauge group is dual to the type IIB superstring theory on AdS(5) x S-5. We use this proposal to study the spectrum of the large N gauge theory on IR x S-3 in a low energy regime. We find that the spectrum is discrete and evenly spaced, and the number of states at each energy level is smaller than the one predicted by the naive extrapolation of the Bekenstein-Hawking formula to the low energy regime. We also show that the gauge theory describes a region of spacetime behind the horizon as well as the region in front. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RP Horowitz, GT (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RI Ooguri, Hirosi/A-4407-2011; OI Ooguri, Hirosi/0000-0001-6021-3778 NR 22 TC 47 Z9 47 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4116 EP 4118 DI 10.1103/PhysRevLett.80.4116 PG 3 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200002 ER PT J AU Adams, J Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Graham, G Graham, J Hagan, KA Halkiadakis, E Hanagaki, K Hazumi, M Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Johnson, PT Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, E Ray, RE Ronzhin, A Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Suzuki, I Stone, RL Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Tripathi, A Tschirhart, R Wah, YW White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED AF Adams, J Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Graham, G Graham, J Hagan, KA Halkiadakis, E Hanagaki, K Hazumi, M Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Johnson, PT Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, E Ray, RE Ronzhin, A Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Suzuki, I Stone, RL Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Tripathi, A Tschirhart, R Wah, YW White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED CA KTeV Collaboration TI Measurement of the branching fraction of the decay K-L ->pi(+)pi(-)e(+)e(-) SO PHYSICAL REVIEW LETTERS LA English DT Article ID CP-VIOLATION; GAMMA AB We report the first branching fraction measurement of the decay K-L --> pi(+)pi(-) e(+)e(-). With a sample of 46 candidates, and an expected background level of 9.4 events, the branching fraction is determined to be B(K-L --> pi(+)pi(-) e(+)e(-)) = [3.2 +/- 0.6(stat) +/- 0.4(syst)] x 10(-7). This measurement was carried out as part of the Fermilab KTeV (E799-II) experiment and is in good agreement with the expectations from the mechanisms of direct emission and inner bremsstrahlung. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Colorado, Boulder, CO 80309 USA. Elmhurst Coll, Elmhurst, IL 60126 USA. Osaka Univ, Toyonaka, Osaka 560, Japan. Rice Univ, Houston, TX 77005 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Virginia, Inst Nucl & Particle Phys, Charlottesville, VA 22901 USA. Univ Wisconsin, Madison, WI 53706 USA. RP O'Dell, V (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. RI Albuquerque, Ivone/H-4645-2012 OI Albuquerque, Ivone/0000-0001-7328-0136 NR 12 TC 26 Z9 26 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4123 EP 4126 DI 10.1103/PhysRevLett.80.4123 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200004 ER PT J AU Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Ford, WT Park, H Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, SL Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, DC Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Patton, S Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F AF Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Ford, WT Park, H Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, SL Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, DC Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Patton, S Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F TI Investigation of semileptonic B meson decays to p-wave charm mesons SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-QUARK SYMMETRY; CB-VERTICAL-BAR; RESONANCES; MODEL AB We have studied semileptonic B meson decays with a p-wave charm meson in the final state using 3.29 x 10(6) B (B) over bar events collected with the CLEO II detector at the Cornell Electron-Positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction B(B- --> D(1)(0)l(-) <(nu)over bar>(l))B(D-1(0)-->D(*+)pi(-) )= (0.373 +/- 0.085 +/- 0.052 +/- 0.024)% and an upper limit for B(B- --> D(2)(*0)l(-)<(nu)over bar>)(l))B(D2O --> D*+ pi(-)) < 0.16% (90% C.L.). Furthermore, we present the first measurement of the q(2) spectrum for B- --> D(1)(0)l(-)<(nu)over bar>(l). C1 Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Champaign, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. BINP, RU-630090 Novosibirsk, Russia. Yonsei Univ, Seoul 120749, South Korea. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Texas, Austin, TX 78712 USA. RP Anastassov, A (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Briere, Roy/N-7819-2014; OI Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674 NR 24 TC 33 Z9 33 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4127 EP 4131 DI 10.1103/PhysRevLett.80.4127 PG 5 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200005 ER PT J AU Appelshauser, H Bachler, J Bailey, SJ Barnby, LS Bartke, J Barton, RA Bialkowska, H Blyth, CO Bock, R Bormann, C Brady, FP Brockmann, R Buncic, N Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Huang, I Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Squier, GTA Stock, R Strobele, H Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Yates, TA Zimanyi, J Zybert, R AF Appelshauser, H Bachler, J Bailey, SJ Barnby, LS Bartke, J Barton, RA Bialkowska, H Blyth, CO Bock, R Bormann, C Brady, FP Brockmann, R Buncic, N Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Huang, I Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Squier, GTA Stock, R Strobele, H Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Yates, TA Zimanyi, J Zybert, R CA NA49 Collaboration TI Directed and elliptic flow in 158GeV/nucleon Pb+Pb collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID RELATIVISTIC NUCLEAR COLLISIONS; COLLECTIVE FLOW; ENERGY; MATTER AB The directed and elliptic flow of protons and charged pions has been observed from the semicentral collisions of a 158 GeV/nucleon Ph beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons but both exhibit negative flow at low p(t). The elliptic flow of both is fairly independent of rapidity but rises with p(t). C1 Univ Athens, Dept Phys, GR-10679 Athens, Greece. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Birmingham, Birmingham, W Midlands, England. KFKI Res Inst Particle & Nucl Phys, Budapest, Hungary. CERN, Geneva, Switzerland. Inst Nucl Phys, Krakow, Poland. Gesell Schwerionenforsch GSI, Darmstadt, Germany. Univ Calif Davis, Davis, CA 95616 USA. Joint Nucl Res Inst, Dubna, Russia. Univ Frankfurt, Fachbereich Phys, D-6000 Frankfurt, Germany. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Univ Washington, Nucl Phys Lab, Seattle, WA 98195 USA. Yale Univ, New Haven, CT 06520 USA. Rudjer Boskovic Inst, Zagreb, Croatia. Moscow Phys Engn Inst, Moscow, Russia. RP Appelshauser, H (reprint author), Univ Heidelberg, Inst Phys, Philosophenweg 12, D-6900 Heidelberg, Germany. RI Barnby, Lee/G-2135-2010; Voloshin, Sergei/I-4122-2013; Levai, Peter/A-1544-2014 OI Barnby, Lee/0000-0001-7357-9904; NR 19 TC 165 Z9 168 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4136 EP 4140 DI 10.1103/PhysRevLett.80.4136 PG 5 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200007 ER PT J AU Holm, DD Marsden, JE Ratiu, TS AF Holm, DD Marsden, JE Ratiu, TS TI Euler-Poincare models of ideal fluids with nonlinear dispersion SO PHYSICAL REVIEW LETTERS LA English DT Article ID INTEGRABLE HAMILTONIAN SYSTEM; PEAKED SOLITONS; MEAN-FLOW; STABILITY; EQUATION; PEAKONS; LATTICE; PDES AB We propose a new class of models for the mean motion of ideal incompressible fluids in three dimensions, including stratification and rotation. In these models, the amplitude of the rapid fluctuations introduces a length scale, alpha, below which wave activity is filtered by both linear and nonlinear dispersion. This filtering enhances the stability and regularity of the new fluid models without compromising either their large scale behavior, or their conservation laws. These models also describe geodesic motion on the volume-preserving diffeomorphism group for a metric containing the H-1 norm of the fluid velocity. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. CALTECH, 107-81, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. RP Holm, DD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B284, Los Alamos, NM 87545 USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 24 TC 146 Z9 147 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4173 EP 4176 DI 10.1103/PhysRevLett.80.4173 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200016 ER PT J AU Hummer, G Garde, S AF Hummer, G Garde, S TI Cavity expulsion and weak dewetting of hydrophobic solutes in water SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-DYNAMICS; FREE-ENERGY; HYDRATION; ENTROPY; SURFACE; FORCES; MODEL; FORMULATION; SIMULATION; LIQUIDS AB Perturbation theory is used to study the solvation of nonpolar molecules in water, supported by extensive computer simulations. Two contributions to the solvent-mediated solute-water interactions an identified: a cavity potential of mean force that transforms by a simple translation when the solute size changes, and a solute-size-independent cavity-expulsion potential. The latter results in weak dewetting of the solute-water interface that can explain the approximate area dependence of solvation free energies with apparent surface tensions similar to macroscopic values. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hummer, G (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS K710, Los Alamos, NM 87545 USA. RI Garde, Shekhar/C-3060-2008; Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 24 TC 112 Z9 112 U1 3 U2 28 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4193 EP 4196 DI 10.1103/PhysRevLett.80.4193 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200021 ER PT J AU Kim, C White, PJ Shen, ZX Tohyama, T Shibata, Y Maekawa, S Wells, BO Kim, YJ Birgeneau, RJ Kastner, MA AF Kim, C White, PJ Shen, ZX Tohyama, T Shibata, Y Maekawa, S Wells, BO Kim, YJ Birgeneau, RJ Kastner, MA TI Systematics of the photoemission spectral function of cuprates: Insulators and hole- and electron-doped superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID COPPER-OXIDE SR2CUO2CL2; T-J MODEL; FERMI-SURFACE; GAP AB Angle-resolved photoemission studies on Sr2CuO2Cl2 at a temperature below its Neel temperature reveal detailed momentum dependent line shape changes as a function of wave vector. While a sharp quasiparticlelike peak is observed near (pi/2, pi/2), broad peaks are observed near (pi, 0). Additional second and third neighbor hopping terms must be added to the t-J Hamiltonian to account for both the dispersion and the line shape. It is found that this Hamiltonian can be used to explain the measured momentum dependent spectral function for hole-doped materials, both underdoped and overdoped, as well as electron-doped materials. C1 Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Tohoku Univ, Inst Mat Res, Sendai, Miyagi 98077, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Kim, C (reprint author), Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. RI Kim, Young-June /G-7196-2011 OI Kim, Young-June /0000-0002-1172-8895 NR 26 TC 221 Z9 222 U1 1 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4245 EP 4248 DI 10.1103/PhysRevLett.80.4245 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200034 ER PT J AU Kralik, B Delaney, P Louie, SG AF Kralik, B Delaney, P Louie, SG TI Correlation effects in the Compton profile of silicon SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM MONTE-CARLO; SYNCHROTRON-RADIATION; MOMENTUM DENSITY; FERMI-SURFACE; ELECTRON-GAS; X-RAYS; SCATTERING; DIAMOND; SI; SOLIDS AB Ab initio nonlocal pseudopotential variational quantum Monte Carlo techniques are used to compute the correlation effects on the valence momentum density and Compton profile of silicon. Our results for this case are in excellent agreement with the Lam-Platzman correction computed within the local density approximation. Within the approximations used, we rule out valence electron correlations as the dominant source of discrepancies between calculated and measured Compton profiles of silicon. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 36 TC 26 Z9 26 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4253 EP 4256 DI 10.1103/PhysRevLett.80.4253 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200036 ER PT J AU Hoekstra, AFT Griessen, R Testa, AM el Fattahi, J Brinkmann, M Westerholt, K Kwok, WK Crabtree, GW AF Hoekstra, AFT Griessen, R Testa, AM el Fattahi, J Brinkmann, M Westerholt, K Kwok, WK Crabtree, GW TI General features of quantum creep in high-T-c superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID UPPER CRITICAL-FIELD; COLLECTIVE CREEP; VORTEX DYNAMICS; THIN-FILMS; TEMPERATURE; ANISOTROPY; SUPERLATTICES; YBA2CU3O7; CRYSTALS; RELAXATION AB Measurements of the relaxation rate Q(T) of superconducting currents have been performed on a carefully selected set of dirty and clean high-T-c;. superconductors for temperatures T down to 100 mK and magnetic fields up to 7 T. The extrapolated relaxation rates Q(0) for the dirty compounds indicate that the viscosity experienced by a tunneling vortex segment is grossly underestimated by the standard Bardeen-Stephen theory. For the clean compounds a universal value Q(0) congruent to 0.022 is found at 1 T, implying that the number of superconducting charge carriers involved in the tunneling of a vortex segment is congruent to 14. C1 Vrije Univ Amsterdam, Inst COMPAS, Amsterdam, Netherlands. Vrije Univ Amsterdam, Fac Phys & Astron, Amsterdam, Netherlands. CNR, ICMAT, Area Ric Roma, Roma, Italy. Ruhr Univ Bochum, Inst Expt Phys Festkorperphys, D-4630 Bochum, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Hoekstra, AFT (reprint author), Vrije Univ Amsterdam, Inst COMPAS, Amsterdam, Netherlands. RI testa, alberto maria/I-8899-2012; OI testa, alberto maria/0000-0002-1898-2730 NR 31 TC 28 Z9 28 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4293 EP 4296 DI 10.1103/PhysRevLett.80.4293 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200046 ER PT J AU Specht, ED Christen, HM Norton, DP Boatner, LA AF Specht, ED Christen, HM Norton, DP Boatner, LA TI X-ray diffraction measurement of the effect of layer thickness on the ferroelectric transition in epitaxial KTaO3/KNbO3 multilayers SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSITION; FILMS; SUPERLATTICES; SURFACE; GROWTH AB KTaO3/KNbO3 strained-layer superlattices of variable periodicity were grown by pulsed laser deposition on KTaO3 substrates. The KNbO3 layers were found to be strained in plane to match the substrate lattice parameter. Therefore, the applied strain is independent of the layer thickness. High-temperature x-ray diffraction was used to measure the ferroelectric-paraelectric phase transition temperature T-c. For superlattice periodicity Lambda less than or equal to 5.1 nm, T-c = 475 K, independent of Lambda. For Lambda > 5.1 nm, T-c increases to 825 K at Lambda = 33.8 nm. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Specht, ED (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. EM esy@ornl.gov RI Christen, Hans/H-6551-2013; Specht, Eliot/A-5654-2009; Boatner, Lynn/I-6428-2013 OI Christen, Hans/0000-0001-8187-7469; Specht, Eliot/0000-0002-3191-2163; Boatner, Lynn/0000-0002-0235-7594 NR 15 TC 139 Z9 140 U1 6 U2 40 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4317 EP 4320 DI 10.1103/PhysRevLett.80.4317 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200052 ER PT J AU Schenkel, T Barnes, AV Hamza, AV Schneider, DH Banks, JC Doyle, BL AF Schenkel, T Barnes, AV Hamza, AV Schneider, DH Banks, JC Doyle, BL TI Synergy of electronic excitations and elastic collision spikes in sputtering of heavy metal oxides SO PHYSICAL REVIEW LETTERS LA English DT Article ID SLOW MULTICHARGED IONS; MULTIPLY CHARGED IONS; LITHIUM-FLUORIDE; SOLIDS AB The emission of secondary ions and neutrals from uranium oxide has been measured for impact of highly charged, heavy ions. Total ablation rates and secondary ion yields increase strongly with projectile charge. The dependencies on projectile charge (16 < q < 70), impact energy (10 keV < E-kin < 1 MeV), and projectile mass of secondary ion yields demonstrate the presence of an interaction regime where electronic excitation by charge neutralization and elastic collision spikes combine synergistically. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Schenkel, T (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 27 TC 60 Z9 69 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 11 PY 1998 VL 80 IS 19 BP 4325 EP 4328 DI 10.1103/PhysRevLett.80.4325 PG 4 WC Physics, Multidisciplinary SC Physics GA ZM538 UT WOS:000073550200054 ER PT J AU Semaniak, J Larson, A Le Padellec, A Stromholm, C Larsson, M Rosen, S Peverall, R Danared, H Djuric, N Dunn, GH Datz, S AF Semaniak, J Larson, A Le Padellec, A Stromholm, C Larsson, M Rosen, S Peverall, R Danared, H Djuric, N Dunn, GH Datz, S TI Dissociative recombination and excitation of CH5+: Absolute cross sections and branching fractions SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, clouds; ISM, molecules; methods, laboratory; molecular processes ID HIGH-RESOLUTION MEASUREMENT; POLYATOMIC IONS; DIELECTRONIC RECOMBINATION; IONOSPHERE; ELECTRONS; MOLECULES; PRODUCTS; H-3(+); H-3+; BEAM AB The heavy-ion storage ring CRYRING was used to measure the absolute dissociative recombination and dissociative excitation cross sections for collision energies below 50 eV. Deduced thermal rates coefficients are consistent with previous beams data but are lower by a factor of 3 than the rates measured by means of the flowing afterglow Langmuir probe technique. A resonant structure in dissociative recombination cross section was found at 9 eV. We have determined the branching fractions in DR of CH5+ below 0.2 eV. The branching is dominated by three-body CH3 + H + H and CH2 + H-2 + H dissociation channels, which occur with branching ratios of approximate to 0.7 and approximate to 0.2, respectively; thus methane is a minor species among dissociation products. Both the measured absolute cross sections and branching in dissociative recombination of CH5+ can have important implications for the models of dense interstellar clouds and abundance of CH2, CH3 and CH4 in these media. C1 Royal Inst Technol, Dept Phys 1, S-10044 Stockholm, Sweden. Univ Stockholm, Dept Phys, S-11385 Stockholm, Sweden. FOM, Inst Atom & Mol Phys, NL-1098 SJ Amsterdam, Netherlands. Stockholm Univ, Manne Siegbahn Lab, S-10405 Stockholm, Sweden. Univ Colorado, JILA, Boulder, CO 80309 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Semaniak, J (reprint author), Royal Inst Technol, Dept Phys 1, S-10044 Stockholm, Sweden. OI Peverall, Robert/0000-0003-2326-2495 NR 45 TC 76 Z9 76 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1998 VL 498 IS 2 BP 886 EP 895 DI 10.1086/305581 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZN664 UT WOS:000073669300034 ER PT J AU Washington-Allen, RA Ramsey, RD Norton, BE West, NE AF Washington-Allen, RA Ramsey, RD Norton, BE West, NE TI Change detection of the effect of severe drought on subsistence agropastoral communities on the Bolivian Altiplano SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID REFLECTANCE; ECOSYSTEMS; SENSOR; MSS AB The purpose of this study was to identify the ecological effects of drought on the vegetation resources of subsistence agropastoral communities on the Bolivian Altiplano. The objectives of the study were to (1) characterize vegetation cover response during a typical year, and (2) identify vegetation cover type's response to drought using an image differencing change detection technique. A geographical information system (GIS), which included multi-temporal (from 1972-1987) Landsat satellite imagery, was used as the assessment tool. Vegetation index difference images showed that (1) all vegetation types were impacted by drought, but the wet meadow vegetation cover type had the least response, and (2) approximately 90 per cent of vegetation cover had not changed between 1972 and 1987. Crop and animal production in agropastoral systems are dependant on the availability of vegetation resources. The wet meadow vegetation type was the most resistant to drought, which suggests that during drought periods it is a key resource upon which the livestock of the community would depend. Little change in vegetation cover over the 15-year span of the study, and the rapid recovery of this parameter following the drought of 1983-84, suggest that agricultural practices (especially livestock grazing) are not contributing to resource degradation when measured only in terms of change in vegetation cover. C1 Oak Ridge Natl Lab, Div Environm Sci, Ecol Sci Sect, Oak Ridge, TN 37831 USA. Utah State Univ, Coll Nat Resources, Dept Geog & Earth Resources, Logan, UT 84322 USA. Utah State Univ, Coll Nat Resources, Dept Rangeland Resources, Logan, UT 84322 USA. RP Washington-Allen, RA (reprint author), Oak Ridge Natl Lab, Div Environm Sci, Ecol Sci Sect, POB 2008,Bldg 1507,MS 6407, Oak Ridge, TN 37831 USA. RI Ramsey, R. Douglas/D-3504-2009 NR 39 TC 18 Z9 18 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 10 PY 1998 VL 19 IS 7 BP 1319 EP 1333 DI 10.1080/014311698215469 PG 15 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA ZM780 UT WOS:000073575100005 ER PT J AU Kierfeld, J AF Kierfeld, J TI Topological order in the phase diagram for high-temperature superconductors with point defects SO PHYSICA C LA English DT Article DE superconductors; topological order; phase diagram ID BA-CU-O; VORTEX-GLASS SUPERCONDUCTIVITY; YBA2CU3O7 SINGLE-CRYSTALS; II SUPERCONDUCTORS; LAYERED SUPERCONDUCTOR; THERMAL FLUCTUATIONS; SQUID PICOVOLTOMETRY; ELASTIC THEORY; FLUX LATTICES; RANDOM-FIELD AB Applying a Lindemann like criterion obtained previously by Kierfeld et al. [J. Kierfeld, T. Nattermann, T. Hwa, Phys. Rev. B 55 (1997) 626], we estimate the magnetic field and temperature for a high-T-c superconductor, at which a topologicalIy ordered vortex glass phase becomes unstable with respect to a disorder-induced formation of dislocations. The employed criterion is shown to be equivalent to a conventional phenomenological Lindemann criterion including the values for the numerical factors, i.e., for the Lindemann number. The positional correlation length of the topologically ordered vortex glass is calculated. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Cologne, Inst Theoret Phys, D-50937 Koln, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Kierfeld, J (reprint author), Univ Cologne, Inst Theoret Phys, D-50937 Koln, Germany. RI Kierfeld, Jan/A-2659-2009 OI Kierfeld, Jan/0000-0003-4291-0638 NR 35 TC 51 Z9 51 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 10 PY 1998 VL 300 IS 3-4 BP 171 EP 183 DI 10.1016/S0921-4534(98)00138-5 PG 13 WC Physics, Applied SC Physics GA ZW303 UT WOS:000074396500002 ER PT J AU Rubenstein, R Gray, PC Wehlburg, CM Wagner, JS Tisone, GC AF Rubenstein, R Gray, PC Wehlburg, CM Wagner, JS Tisone, GC TI Detection and discrimination of PrP(Sc) by multi-spectral ultraviolet fluorescence SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article ID MOLECULAR-BASIS; SCRAPIE; STRAIN; HAMSTERS AB Prion diseases are progressive degenerative disorders of the central nervous system. The transmissibility and fatal nature of these diseases necessitate their rapid and accurate diagnosis. The hallmark of these diseases is the accumulation of PrP(Sc), a protease-resistant form of a host-coded glycoprotein. We have been evaluating the use of multi-spectral ultraviolet fluorescent spectroscopy as a means of detecting and distinguishing between different forms of PrP(Sc). Spectroscopic measurements of fluorescence from untreated and proteinase K (PK)-treated PrP(Sc), purified from 263K scrapie strain-infected hamster brains and ME7 scrapie strain-infected mouse brains, were performed. Spectra of untreated and PK-treated PrP(Sc) samples for 263K and ME7 appeared qualitatively different. The identification and discrimination of PrP(Sc) were possible based on these spectral signatures, calculations of their fluorescence cross sections, and determination of the orthogonal differences. This technique has the potential not only for the sensitive, specific, and direct detection of PrP(Sc), beat also for the ability to distinguish between different forms of the prion protein. (C) 1998 Academic Press. C1 New York State Inst Basic Res Dev Disabil, Staten Isl, NY 10312 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. TW Res Associates, Albuquerque, NM 87108 USA. RP Rubenstein, R (reprint author), New York State Inst Basic Res Dev Disabil, 1050 Forest Hill Rd, Staten Isl, NY 10312 USA. NR 23 TC 34 Z9 38 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD MAY 8 PY 1998 VL 246 IS 1 BP 100 EP 106 DI 10.1006/bbrc.1998.8542 PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ZP868 UT WOS:000073796700019 PM 9600075 ER PT J AU Colvin, ME Janssen, CL Seidl, ET Nielsen, IMB Melius, CF AF Colvin, ME Janssen, CL Seidl, ET Nielsen, IMB Melius, CF TI Energies, resonance and UHF instabilities in polycyclic aromatic hydrocarbons and linear polyenes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BOND LENGTH ALTERNATION; MEDIUM-SIZED HYDROCARBONS; HARTREE-FOCK METHOD; CYCLIC POLYENES; ABINITIO HEATS AB We have performed ab initio restricted Hartree-Fock (RHF) and restricted second-order Moller-Plesset perturbation theory (RMP2) calculations of the relative energies of all C20H12, C18H12 and C14H10 polycyclic aromatic hydrocarbons (PAHs). Since all of these PAH wavefunctions exhibit large unrestricted Hartree-Fock (UHF) instabilities, the C14H10 PAHs were also studied using higher levels of electron correlation. Additionally, the role of UHF instabilities was investigated for the the linear conjugated polyenes from C2H4 to C20H22. Our results suggest that the RHF and RMP2 methods yield energies in relatively good agreement with highly electron-correlated methods, but the UHF instabilities indicate a fundamental shortcoming of the single determinant wavefunction description of these systems. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Limit Point Syst Inc, Fremont, CA 94538 USA. Sandia Natl Labs, Sci Computing Dept, Livermore, CA 94551 USA. Aarhus Univ, Dept Chem, DK-8000 Aarhus C, Denmark. RP Colvin, ME (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mailstop L-452, Livermore, CA 94550 USA. EM colvin2@llnl.gov NR 20 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 8 PY 1998 VL 287 IS 5-6 BP 537 EP 541 DI 10.1016/S0009-2614(98)00228-0 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZP121 UT WOS:000073718500009 ER PT J AU Xie, B Laouar, A Huberman, E AF Xie, B Laouar, A Huberman, E TI Fibronectin-mediated cell adhesion is required for induction of 92-kDa type IV collagenase/gelatinase (MMP-9) gene expression during macrophage differentiation - The signaling role of protein kinase C-beta SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID COLONY-STIMULATING FACTOR; ESTER-INDUCED DIFFERENTIATION; PROMYELOCYTIC LEUKEMIA-CELLS; HUMAN MONONUCLEAR PHAGOCYTES; HUMAN ALVEOLAR MACROPHAGES; MATRIX METALLOPROTEINASE-9; MONOCYTIC DIFFERENTIATION; TERMINAL DIFFERENTIATION; NEUTRAL PROTEINASES; POTENT INHIBITORS AB Induction of the 92-kDa gelatinase (MMP-9) gene expression is associated with macrophage differentiation. In this study, we explored the regulatory mechanisms underlying this differentiation-associated MMP-9 gene expression in human HL-60 myeloid leukemia cells and human peripheral blood monocytes. Phorbol 12-myristate 13-acetate (PMA) markedly induced MMP-9 gene expression in HL-60 cells; the induction closely paralleled the timing and extent of PMA-induced cell adhesion and spreading, a hallmark of macrophage differentiation. Similarly, treatment with PMA or macrophage-colony stimulating factor stimulated adherence and spreading of blood monocytes with a concurrent 7- or 5-fold increase in MMP-9 production, respectively. In protein kinase C (PRC)-beta-deficient HL-60 variant cells (HL-525), PMA failed to induce cell adhesion and MMP-9 gene expression. Transfecting HL-525 cells with a PKC-beta expression plasmid restored PKC-beta levels and PMA inducibility of cell adhesion and spreading as well as MMP-9 gene expression. Induction of cell adhesion and MMP-9 gene expression in HL-60 cells and blood monocytes was strongly inhibited by neutralizing monoclonal antibodies to fibronectin (FN) and its receptor alpha(5) beta(1) integrin. HL-525 cells, which constitutively display high levels of surface alpha(5) beta(1) integrin, adhered and spread on immobilized FN with concomitant induction of MMP-9 gene expression. Cytochalasins B and D were each a potent inhibitor of MMP-9 production. Our results suggest that alpha(5) beta(1) integrin-mediated interaction of immature hematopoietic cells with FN plays a critical role in modulating matrix-degrading activities during macrophage differentiation. C1 Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. RP Huberman, E (reprint author), Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 58 TC 95 Z9 103 U1 2 U2 9 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAY 8 PY 1998 VL 273 IS 19 BP 11576 EP 11582 DI 10.1074/jbc.273.19.11576 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZM408 UT WOS:000073536700028 PM 9565574 ER PT J AU Xie, B Laouar, A Huberman, E AF Xie, B Laouar, A Huberman, E TI Autocrine regulation of macrophage differentiation and 92-kDa gelatinase production by tumor necrosis factor-alpha via alpha(5)beta(1) integrin in HL-60 cells SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID PROMYELOCYTIC LEUKEMIA-CELLS; COLONY-STIMULATING FACTOR; HUMAN MONONUCLEAR PHAGOCYTES; COLLAGENASE GENE-EXPRESSION; IV COLLAGENASE; MATRIX METALLOPROTEINASE-9; TNF-ALPHA; MECHANISM; PROLIFERATION; LEUKOCYTES AB Tumor necrosis factor-alpha (TNF-alpha) gene is one of the early response genes induced by phorbol la-myristate 13-acetate (PMA) in human HL-60 myeloid leukemia cells. In the present study, we examined the role of the TNF-alpha autocrine loop in PMA-induced macrophage differentiation and gene expression of 92- and 72-kDa gelatinases (MMP-9 and MMP-2). In HL-60 cells, PMA inhibited cell proliferation and induced cell adhesion and spreading, expression of surface maturation marker OKM1 and phagocytic activity, as well as the expression of both gelatinases, which all characterize the macrophage phenotype. In contrast, TNF-alpha alone was only effective in inhibiting cell proliferation. Blocking the endogenous TNF-alpha activity with neutralizing anti-TNF-alpha antibodies abolished all these PMA-induced events with the exception of MMP-2 gene expression. Since fibronectin (FN)-mediated cell adhesion and spreading are prerequisite for both macrophage differentiation and MMP-9 gene expression in HL-60 cells, we hypothesized that TNF-alpha might be involved in modulating the expression of either the FN or its integrin receptor genes. Whereas PMA substantially enhanced the steady state mRNA and protein levels of both FN and alpha(5) beta(1) integrins, TNF-alpha alone had little effect on the expression of these genes. However, anti-TNF-alpha antibodies blocked PMA-induced augmentation of both alpha(5) and beta(1) integrin gene expression without affecting the expression of the FN gene. Our results suggest that TNF-alpha may regulate macrophage differentiation and critical matrix-degrading activities of myeloid progenitor cells in an autocrine manner by augmenting surface levels of the alpha(5) beta(1) integrin, thus promoting interactions with the extracellular matrix, a key event for maturation and migration of these cells during inflammation. C1 Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. RP Huberman, E (reprint author), Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 34 TC 54 Z9 54 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAY 8 PY 1998 VL 273 IS 19 BP 11583 EP 11588 DI 10.1074/jbc.273.19.11583 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZM408 UT WOS:000073536700029 PM 9565575 ER PT J AU Xu, CS Taylor, TR Burton, GR Neumark, DM AF Xu, CS Taylor, TR Burton, GR Neumark, DM TI Photoelectron spectroscopy of SinH- (n = 2-4) anions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NEGATIVE-ION PHOTODETACHMENT; SURFACE; SPECTRA; STATES; CHEMISORPTION; DEPOSITION; DISILYNE; SI(100); SYSTEMS; SI2H2 AB Vibrationally resolved photoelectron spectra of SinH- (n=2-4) have been measured at a photodetachment wavelength of 355 nm (3.493 eV). The electron affinities of Si2H, Si3H, and Si4H are 2.31 +/- 0.01, 2.53 +/- 0.01, and 2.68 +/- 0.01 eV, respectively. Vibrational frequencies for the neutral ground states and a low-lying state of Si2H are also determined. Assignment of the electronic states and vibrational frequencies is facilitated by comparison with ab initio calculations. The calculations show that the H atom in Si4H and Si4H- is bonded to a single Si atom, in contrast to the bridged structures found for the smaller clusters. These calculations, along with photoelectron energy and angular distributions, yield a definitive assignment of the ground and nearly degenerate first excited states of Si2H. (C) 1998 American Institute of Physics. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Xu, CS (reprint author), Lam Res Corp, 47131 Bayside Pkwy, Fremont, CA 94538 USA. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 28 TC 38 Z9 40 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1998 VL 108 IS 18 BP 7645 EP 7652 DI 10.1063/1.476200 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZL319 UT WOS:000073420800018 ER PT J AU Tammaro, M Evans, JW AF Tammaro, M Evans, JW TI Reactive removal of unstable mixed NO+CO adlayers: Chemical diffusion and reaction front propagation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPATIOTEMPORAL SELF-ORGANIZATION; CONCENTRATED LATTICE GASES; SURFACE-REACTION; PT(100); SYNCHRONIZATION; OSCILLATIONS; NUCLEATION; PARTICLES; SUBSTRATE; BEHAVIOR AB A lattice-gas model is developed to describe the reactive removal of a preadsorbed, mixed NO+CO adlayer covering a Pt(100) surface, via reduction of NO with CO, and behavior of the model is analyzed. Since NO dissociation requires an adjacent empty site, the NO+CO covered surface constitutes an unstable steady state. The creation of vacancies leads NO dissociation, the reaction of CO with the O formed by dissociation, the subsequent creation of more vacancies, and thus the autocatalytic removal of the adlayer. The high mobility of most adspecies leads to an initial "disperse stage" of adlayer removal, characterized by an exponential increase in the number of highly dispersed vacancies. Thereafter follows a transition to a "reaction front propagation" stage of adlayer removal, where a chemical wave develops that propagates into the NO+CO covered region of the surface with roughly constant velocity, and leaves in its wake a surface populated only by excess reactant. We provide a suitable rate equation formulation for the initial disperse stage, but focus on a reaction-diffusion equation analysis of reaction front propagation, examining, in detail, behavior for long times where the front is nearly planar. We emphasize that it is necessary to incorporate the coverage-dependent and tensorial nature of chemical diffusion in the mixed adlayer. Both these features reflect the interference on the surface diffusion of each adspecies by coadsorbed species. Thus, a key component of this work is the development of an appropriate treatment of chemical diffusion in mixed layers of several adspecies. (C) 1998 American Institute of Physics. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. RP Evans, JW (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. EM evans@ameslab.gov NR 35 TC 32 Z9 32 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1998 VL 108 IS 18 BP 7795 EP 7806 DI 10.1063/1.476215 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZL319 UT WOS:000073420800034 ER PT J AU Graham, AP Hofmann, F Toennies, JP Williams, GP Hirschmugl, CJ Ellis, J AF Graham, AP Hofmann, F Toennies, JP Williams, GP Hirschmugl, CJ Ellis, J TI A high resolution helium atom scattering and far infrared study of the dynamics and the lateral potential energy surface of CO molecules chemisorbed on Cu(001) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID REFLECTION-ABSORPTION-SPECTROSCOPY; CU(100); DIFFUSION; VIBRATIONS; MODE; TEMPERATURES; RELAXATION; CO/CU(100); NI(100); PHONONS AB Inelastic helium scattering (HAS) and infrared reflection adsorption spectroscopy (IRAS) have been used to measure the isotope shifts of the frequencies of both the parallel and perpendicular frustrated translation modes, as well as the frustrated rotation mode of CO molecules at on top sites on Cu(001). The measured isotope shifts for four different isotopomers indicates a significant rotational contribution to the parallel frustrated translation (T-mode), where the vibrational amplitude of the oxygen atom is significantly larger than for the carbon atom. Conversely, for the frustrated rotation the vibrational amplitude of the carbon atom was observed to be larger than for the oxygen atom. At surface temperatures above T-s=100 K a careful analysis of the peak shape of the HAS quasielastic peak shows a small broadening, which is attributed to a rapid diffusion of the CO molecules. The measured dynamic diffusion barrier of 31 +/- 10 meV is compatible with the shape of the potential at the on-top site and makes it possible to extend the potential energy surface to the region between the on-top sites. (C) 1998 American Institute of Physics. C1 Max Planck Inst Stromungsforsch, D-37073 Gottingen, Germany. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ E Anglia, Sch Phys, Norwich NR4 7TJ, Norfolk, England. RP Graham, AP (reprint author), Max Planck Inst Stromungsforsch, Bunsenstr 10, D-37073 Gottingen, Germany. NR 48 TC 59 Z9 59 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1998 VL 108 IS 18 BP 7825 EP 7834 DI 10.1063/1.476219 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZL319 UT WOS:000073420800038 ER PT J AU Martin, JE Anderson, RA Tigges, CP AF Martin, JE Anderson, RA Tigges, CP TI Simulation of the athermal coarsening of composites structured by a biaxial field SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article AB We report the results of a computer simulation of the evolution of structure in a two component fluid consisting of a liquid phase and a dispersed colloidal phase subjected to a biaxial field. A biaxial field, such as a rotating field, can induce the organization of polarizable particles into two-dimensional sheets, in contrast with the essentially one-dimensional columns formed in a uniaxial field. Our primary objective is to explore the kinetics of coarsening, the emergence of structure, and the anisotropy in materials properties. Using an efficient, linear-N simulation method we report studies of systems of N=10 000 particles over the concentration range of phi = 10-50 vol %. We present a variety of methods of characterizing the structures that emerge, including the two dimensional pair correlation, velocity correlations, microcrystallinity, optical attenuation, dipolar interaction energy, conductivity, and permittivity. The anisotropies that we compute are generally inverted relative to those found in materials structured by a uniaxial field. (C) 1998 American Institute of Physics. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Martin, JE (reprint author), Sandia Natl Labs, Albuquerque, NM 87185 USA. NR 8 TC 59 Z9 62 U1 2 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1998 VL 108 IS 18 BP 7887 EP 7900 DI 10.1063/1.476226 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZL319 UT WOS:000073420800046 ER PT J AU Fung, EN Pang, HM Yeung, ES AF Fung, EN Pang, HM Yeung, ES TI Fast DNA separations using poly(ethylene oxide) in non-denaturing medium with temperature programming SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE gel preparation; DNA; poly(ethylene oxide) ID CAPILLARY GEL-ELECTROPHORESIS; INDUCED FLUORESCENCE DETECTION; CROSS-LINKED POLYACRYLAMIDE; HIGH-SPEED; HIGH-RESOLUTION; LOW-COST; FRAGMENTS; ENERGY; ARRAY; DYES AB We demonstrated fast DNA separations in low viscosity entangled solutions with a temperature gradient in a nondenaturing separation medium. The separations were carried out in a solution of commercially available poly(ethylene oxide) (PEO) [1xTris(hydroxymethyl)aminomethane berate buffer, without urea] with a temperature gradient of 2 degrees C/min. The performance was compared with that of a solution of PEO with urea at ambient temperature. We found that the former condition gives sufficient resolution for accurate base calling and that in general, it gave better separation for fragments larger than 450 base pairs (bp). Most importantly, the separation speed approaches 30 bp/min. In addition, we describe a simple yet reliable gel preparation protocol for such separations. (C) 1998 Elsevier Science B.V. C1 US DOE, Ames Lab, Ames, IA 50011 USA. RP Yeung, ES (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. FU NHGRI NIH HHS [HG-01385] NR 21 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 8 PY 1998 VL 806 IS 1 BP 157 EP 164 DI 10.1016/S0021-9673(97)00812-1 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZR010 UT WOS:000073926500014 PM 9639886 ER PT J AU Ambrose, DL Fritz, JS AF Ambrose, DL Fritz, JS TI High-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve SO JOURNAL OF CHROMATOGRAPHY B LA English DT Article DE molecular sieves; silicalite ID COLUMN; SILICA AB Silicalite is a molecular sieve that contains an intricate system of channels approximately 6 Angstrom in diameter. These channels an hydrophobic and have been shown to retain relatively small hydrophobic and hydrophilic molecules from aqueous and biological samples. Silicalite is shown to be a restricted-access medium that permits the injection of biological fluids directly onto a HPLC column packed with Silicalite, eliminating the need for sample preparation. The sample macromolecules elute with high recovery mostly at the extraparticulate void. Simultaneously, Silicalite allows various drugs and metabolites to enter the channels and be retained. Recoveries >90% were generally obtained for a wide variety of drugs and their metabolites from human serum and urine. (C) 1998 Elsevier Science B.V. C1 Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Fritz, JS (reprint author), Iowa State Univ Sci & Technol, Dept Chem, 332 Wilhelm Hall, Ames, IA 50011 USA. NR 20 TC 12 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B PD MAY 8 PY 1998 VL 709 IS 1 BP 89 EP 96 DI 10.1016/S0378-4347(98)00015-2 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZR379 UT WOS:000073968800010 PM 9653929 ER PT J AU Chen, Y David, SA Zacharia, T Cremers, CJ AF Chen, Y David, SA Zacharia, T Cremers, CJ TI Marangoni convection with two free surfaces SO NUMERICAL HEAT TRANSFER PART A-APPLICATIONS LA English DT Article ID WELD POOL OSCILLATION; RECTANGULAR CAVITY; FLOW AB A numerical model is presented for a two-dimensional surface-tension-driven flow with two free surfaces, as is the case for a stationary full-penetration weld. Focus is on the flow patterns with the presence of two free surfaces and how they differ from those with one free surface. A standard splining scheme is used to numerically solve the governing equations with primitive variables u, v, p, T and the locations of the free surfaces. Results for several combinations of Reynolds number, capillary number, Bond number, and external pressure are presented If is found that with low Reynolds number, thermocapillary flows with two free surfaces have stronger secondary vortex than those with one free surface. For two-free-surface flaws with high Reynolds number, thermocapillary forces at the bottom free surface are strong enough to generate a secondary vortex that is comparable to the primary vortex generated by the thermocapillary forces at the top free surface. Furthermore, two-free-surface flows are more flexible than one-free-surface flows; therefore, under the same conditions, the former oscillate with a higher frequency than the later. This is consistent with prior experimental observation and analytical investigation. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Kentucky, Dept Mech Engn, Lexington, KY 40506 USA. RP Zacharia, T (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6140, Oak Ridge, TN 37831 USA. OI Zacharia, Thomas/0000-0001-6463-5425 NR 14 TC 11 Z9 11 U1 0 U2 1 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 1040-7782 J9 NUMER HEAT TR A-APPL JI Numer. Heat Tranf. A-Appl. PD MAY 8 PY 1998 VL 33 IS 6 BP 599 EP 620 DI 10.1080/10407789808913957 PG 22 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA ZM711 UT WOS:000073568200003 ER PT J AU Agosto, M Allan, J Benson, C Berger, EA Blumenthal, R Burton, D Clements, J Coffin, J Connor, R Cullen, B Desrosiers, R Dimitrov, D Doms, R Emerman, M Feinberg, M Fultz, P Gerard, C Gonsalves, G Haase, A Haigwood, N Hirsch, V Ho, D Hoxie, JA Hu, SL Hunter, E Johnson, P Kawata, PA Korber, B Kuiken, C Learn, GH Leitner, T Lewis, G Link, D Luban, J Luzuriaga, K Malim, M Marx, P McCune, JM Montefiori, D Moore, J Morrow, C Mosier, D Muesing, M Nixon, D Nunberg, J Overbaugh, J Parren, P Planelles, V Pope, M Posnett, DN Siliciano, R Steinman, R Stevenson, M Swanstrom, R Walker, BD Wolinsky, S Zingale, D AF Agosto, M Allan, J Benson, C Berger, EA Blumenthal, R Burton, D Clements, J Coffin, J Connor, R Cullen, B Desrosiers, R Dimitrov, D Doms, R Emerman, M Feinberg, M Fultz, P Gerard, C Gonsalves, G Haase, A Haigwood, N Hirsch, V Ho, D Hoxie, JA Hu, SL Hunter, E Johnson, P Kawata, PA Korber, B Kuiken, C Learn, GH Leitner, T Lewis, G Link, D Luban, J Luzuriaga, K Malim, M Marx, P McCune, JM Montefiori, D Moore, J Morrow, C Mosier, D Muesing, M Nixon, D Nunberg, J Overbaugh, J Parren, P Planelles, V Pope, M Posnett, DN Siliciano, R Steinman, R Stevenson, M Swanstrom, R Walker, BD Wolinsky, S Zingale, D TI AIDS vaccine development SO SCIENCE LA English DT Letter C1 Natl Minor AIDS Council, Washington, DC USA. SW Fdn Med Res, San Antonio, TX USA. Univ Colorado, Denver, CO 80202 USA. NIAID, NIH, Bethesda, MD 20892 USA. NCI, Bethesda, MD 20892 USA. Scripps Res Inst, La Jolla, CA USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Tufts Univ, Boston, MA 02111 USA. Aaron Diamond AIDS Res Ctr, New York, NY USA. Duke Univ, Durham, NC USA. Harvard Univ, Southborough, MA USA. Univ Penn, Philadelphia, PA 19104 USA. Fred Hutchinson Canc Res Ctr, Seattle, WA 98104 USA. Emory Univ, Atlanta, GA 30322 USA. Univ Alabama, Birmingham, AL USA. Treatment Act Grp, New York, NY USA. Univ Minnesota, Minneapolis, MN 55455 USA. Univ Washington, Seattle, WA 98195 USA. Ohio State Univ, Columbus, OH 43210 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Maryland, Baltimore, MD 21201 USA. Gay Mens Hlth Crisis Inc, New York, NY USA. Columbia Univ, New York, NY 10027 USA. Univ Massachusetts, Worcester, MA 01605 USA. Univ Calif San Francisco, Gladstone Inst Virol & Immunol, San Francisco, CA 94143 USA. Rockefeller Univ, New York, NY 10021 USA. Cornell Univ, Coll Med, New York, NY USA. Univ N Carolina, Chapel Hill, NC 27515 USA. Harvard Univ, Massachusetts Gen Hosp, Sch Med, Boston, MA USA. Northwestern Univ, Sch Med, Chicago, IL USA. AIDS Act Council, Washington, DC USA. RP Agosto, M (reprint author), Natl Minor AIDS Council, Washington, DC USA. RI Wolinsky, Steven/B-2893-2012; Steinman, Ralph/F-7729-2012 NR 1 TC 2 Z9 2 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 8 PY 1998 VL 280 IS 5365 BP 803 EP + PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZM380 UT WOS:000073532900002 PM 9599148 ER PT J AU Pesiri, DR Morita, DK Glaze, W Tumas, W AF Pesiri, DR Morita, DK Glaze, W Tumas, W TI Selective epoxidation in dense phase carbon dioxide SO CHEMICAL COMMUNICATIONS LA English DT Article ID CATALYZED EPOXIDATIONS; ALLYLIC ALCOHOLS; OXIDATION AB Selective epoxidations with transition metal catalysts (V, Ti, Mo) and (BuOOH)-O-t proceed with high conversions and high selectivity in dense phase carbon dioxide. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ N Carolina, Dept Environm Sci & Engn, Chapel Hill, NC 27599 USA. Univ N Carolina, Carolina Environm Program, Chapel Hill, NC 27599 USA. RP Tumas, W (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 33 Z9 33 U1 0 U2 2 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD MAY 7 PY 1998 IS 9 BP 1015 EP 1016 DI 10.1039/a801655k PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZM375 UT WOS:000073532200033 ER PT J AU Franchetti, P Cappellacci, L Perlini, P Jayaram, HN Butler, A Schneider, BP Collart, FR Huberman, E Grifantini, M AF Franchetti, P Cappellacci, L Perlini, P Jayaram, HN Butler, A Schneider, BP Collart, FR Huberman, E Grifantini, M TI Isosteric analogues of nicotinamide adenine dinucleotide derived from furanfurin, thiophenfurin, and selenophenfurin as mammalian inosine monophosphate dehydrogenase (type I and II) inhibitors SO JOURNAL OF MEDICINAL CHEMISTRY LA English DT Article ID 2-BETA-D-RIBOFURANOSYLTHIAZOLE-4-CARBOXAMIDE NSC 286193; HUMAN NORMAL LYMPHOCYTES; HUMAN IMP DEHYDROGENASE; TIAZOFURIN; 2-BETA-D-RIBOFURANOSYLSELENAZOLE-4-CARBOXAMIDE; CONVERSION; EXPRESSION; MECHANISM; THIAZOLE; BINDING AB Dinucleotides TFAD (6), FFAD (7), and SFAD (8), isosteric NAD analogues derived, respectively, from C-nucleosides 5-beta-D-ribofuranosylthiophene-3-carboxamide (thiophenfurin, 1), 5-beta-D-ribofuranosylfuran-3-carboxamide (furanfurin, 2), and 5-beta-D-ribofuranosylselenophene-3-carboxamide (selenophenfurin, 5), were synthesized as human inosine monophosphate dehydrogenase (IMPDH) type I and II inhibitors. The synthesis was carried out by imidazole-catalyzed coupling of the 5'-monophosphate of 1, 2, and 5 with AMP. These dinucleotides, which are also analogues of thiazole-4-carboxamide adenine dinucleotide (TAD) and selenazole-4-carboxamide adenine dinucleotide (SAD), the active metabolites of the oncolytic C-nucleosides 2-beta-D-ribofuranosylthiazole-4-carboxamide (tiazofurin) and 2-beta-D-ribofuranosylselenazole-4-carboxamide (selenazofurin), were evaluated for their inhibitory potency against recombinant human IMPDH type I and II. The order of inhibitory potency found was SAD > SFAD = TFAD = TAD much greater than FFAD for both enzyme isoforms. No significant difference was found in inhibition of IMPDH type I and II. C1 Univ Camerino, Dipartimento Sci Chim, I-62032 Camerino, Italy. Indiana Univ, Sch Med, Expt Oncol Lab, Indianapolis, IN 46202 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Franchetti, P (reprint author), Univ Camerino, Dipartimento Sci Chim, Via S Agostino 1, I-62032 Camerino, Italy. OI Collart, Frank/0000-0001-6942-4483 NR 27 TC 41 Z9 41 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-2623 J9 J MED CHEM JI J. Med. Chem. PD MAY 7 PY 1998 VL 41 IS 10 BP 1702 EP 1707 DI 10.1021/jm970772e PG 6 WC Chemistry, Medicinal SC Pharmacology & Pharmacy GA ZM276 UT WOS:000073522300017 PM 9572896 ER PT J AU Winter, PR Rowland, B Hess, WP Radziszewski, JG Nimlos, MR Ellison, GB AF Winter, PR Rowland, B Hess, WP Radziszewski, JG Nimlos, MR Ellison, GB TI UV photodissociation of matrix-isolated propionyl chloride SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PHOTOIONIZATION MASS-SPECTROMETRY; PHASE CONTINUITY PRINCIPLE; ACETYL-CHLORIDE; DISSOCIATION DYNAMICS; SELECTION-RULES; CARBONYL GROUPS; ALPHA-BOND; HEAT; CATION; THERMOCHEMISTRY AB We have investigated the photodecomposition of propionyl chloride, CH3CH2COCl, in an argon matrix at 10 K using FTIR absorption spectroscopy. The decomposition products formed following irradiation at 266, 254, or 248 nm are methyl ketene, CH3CH=CO, and HCl; no other photoproducts are observed. We have carried out FTIR polarization studies to determine the relative orientation of the photoproducts and found that the HCl molecule is situated perpendicular to the carbonyl group in the methyl ketene. The orientation in the photoproducts and kinetic studies of the acid chloride dissociation point to a direct elimination mechanism for propionyl chloride decomposition. This is consistent with the direct mechanism proposed for acetyl chloride, CH3COCl, photodissociation in both an argon matrix and the solid crystalline form. We have calculated detailed thermodynamics for CH3COCl and CH3CH2COCl decomposition and found them consistent with the proposed elimination mechanism. We also assign the fundamental vibrational frequencies for the methyl ketene-HCl complex on the basis of ab initio calculations and polarization studies. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA. NR 58 TC 26 Z9 26 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 7 PY 1998 VL 102 IS 19 BP 3238 EP 3248 DI 10.1021/jp980286i PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZP699 UT WOS:000073779600004 ER PT J AU Hummer, G Pratt, LR Garcia, AE Garde, S Berne, BJ Rick, SW AF Hummer, G Pratt, LR Garcia, AE Garde, S Berne, BJ Rick, SW TI Reply to comment on "Electrostatic potentials and free energies of solvation of polar and charged molecules" SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID WATER; HYDRATION; MODEL C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Columbia Univ, Dept Chem, New York, NY 10027 USA. Columbia Univ, Ctr Biomol Simulat, New York, NY 10027 USA. NCI, Frederick Canc Res & Dev Ctr, Frederick, MD 21702 USA. RP Hummer, G (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS K710, Los Alamos, NM 87545 USA. RI Garde, Shekhar/C-3060-2008; Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 14 TC 41 Z9 42 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 7 PY 1998 VL 102 IS 19 BP 3841 EP 3843 DI 10.1021/jp980145g PG 3 WC Chemistry, Physical SC Chemistry GA ZP697 UT WOS:000073779400027 ER PT J AU Bowmaker, GA Leger, JM Le Rille, A Melendres, CA Tadjeddine, A AF Bowmaker, GA Leger, JM Le Rille, A Melendres, CA Tadjeddine, A TI Investigation of the vibrational properties of OCN- on a silver electrode by in situ synchrotron far infrared spectroscopy and visible-infrared sum frequency generation spectroscopy SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID IN-SITU; THIOCYANATE; ADSORBATES; RADIATION; INTERFACE AB The vibrational properties of cyanate ions, OCN-, adsorbed on a polycrystalline silver electrode in neutral aqueous solution have been studied by in situ VIS-IR sum frequency generation (SFC) and by synchrotron far-IR spectroscopy. The SFG spectra show two bands, one in the region 2100-2130 cm(-1) in the potential range from -0.6 to 0 V vs. SCE, and another in the region 2200-2240 cm(-1) in the potential range from 0 to 4 V. These bands are assigned to the antisymmetric stretching mode of OCN- ions bound to the Ag surface. The lower wavenumber band is assigned to cyanate N-bound to a bridging surface site, whereas the higher wavenumber band is assigned to cyanate in a terminal N-bonding mode. These assignments are consistent with the results of earlier IR absorption studies. The far-IR spectrum shows a broad band at about 360 cm(-1) at electrode potentials above 0 V. This is assigned to the v(AgN) mode of terminally bound cyanate, in accordance with the assignment for the VIS-IR SFG band observed at these potentials. The far-IR spectrum also shows a sharper band at 90 cm(-1) that might arise from a bending (or restricted rotation) of cyanate on the silver surface. C1 Univ Auckland, Dept Chem, Auckland, New Zealand. Univ Poitiers, CNRS, UMR6503, F-86022 Poitiers, France. Univ Paris Sud, LURE, CNRS, F-91405 Orsay, France. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Bowmaker, GA (reprint author), Univ Auckland, Dept Chem, Private Bag 92019, Auckland, New Zealand. RI LEGER, Jean-Michel/D-1125-2013 OI LEGER, Jean-Michel/0000-0002-9879-5029 NR 21 TC 11 Z9 11 U1 1 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD MAY 7 PY 1998 VL 94 IS 9 BP 1309 EP 1313 DI 10.1039/a708381e PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZM824 UT WOS:000073580000022 ER PT J AU Wein, LM D'Amato, RM Perelson, AS AF Wein, LM D'Amato, RM Perelson, AS TI Mathematical analysis of antiretroviral therapy aimed at HIV-1 eradication or maintenance of low viral loads SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; REVERSE-TRANSCRIPTASE; IN-VIVO; POPULATION-DYNAMICS; ZIDOVUDINE THERAPY; DRUG-RESISTANCE; T-LYMPHOCYTES; INFECTION; TYPE-1; REPLICATION AB Motivated by the ability of combinations of antiretroviral agents to sustain viral suppression in HIV-1-infected individuals, we analyse the transient and steady-state behavior of a mathematical model of HIV-1 dynamics in vivo in order to predict whether these drug regimens can eradicate HIV-1 or maintain viral loads at low levels. The model incorporates two cell types (CD4(+) T cells and a long-lived pool of cells), two strains of virus (drug-sensitive wild type and drug-resistant mutant) and two types of antiretroviral agents (reverse transcriptase and protease inhibitors). The transient behavior of the cells and virus and the eventual eradication of the virus are determined primarily by the strength of the combination therapy against the mutant strain and the maximum achievable increase in the uninfected CD4(+) T cell concentration. We also predict, if the parameters of the model remain constant during therapy, that less intensive maintenance regimens will be unable to maintain low viral loads for extensive periods of time. However, if the reduction in viral load produced by therapy reduces the state of activation of the immune system, the number of cells susceptible for HIV-1 infection may decrease even though total CD4(+) T cells increase. Our model predicts that if this occurs strong inductive therapy that reduces viral load followed by weaker maintenance regimes may succeed. C1 MIT, Sloan Sch Management, Cambridge, MA 02139 USA. MIT, Ctr Operat Res, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Wein, LM (reprint author), MIT, Sloan Sch Management, Cambridge, MA 02139 USA. FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI40387] NR 73 TC 89 Z9 90 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD MAY 7 PY 1998 VL 192 IS 1 BP 81 EP 98 DI 10.1006/jtbi.1997.0622 PG 18 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA ZQ604 UT WOS:000073884700009 PM 9628841 ER PT J AU McEuen, PL AF McEuen, PL TI Nanotechnology - Carbon-based electronics SO NATURE LA English DT Editorial Material ID NANOTUBES C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP McEuen, PL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 366 LeConte Hall, Berkeley, CA 94720 USA. NR 11 TC 159 Z9 162 U1 0 U2 27 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 7 PY 1998 VL 393 IS 6680 BP 15 EP + DI 10.1038/29874 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZM028 UT WOS:000073497500021 ER PT J AU Mok, SC Chan, WY Wong, KK Cheung, KK Lau, CC Ng, SW Baldini, A Colitti, CV Rock, CO Berkowitz, RS AF Mok, SC Chan, WY Wong, KK Cheung, KK Lau, CC Ng, SW Baldini, A Colitti, CV Rock, CO Berkowitz, RS TI DOC-2, a candidate tumor suppressor gene in human epithelial ovarian cancer SO ONCOGENE LA English DT Article DE ovary; cancer; DOC-2; Dab; tumor suppressor ID PROLINE-RICH PEPTIDES; SH3 DOMAINS; P53 GENE; BINDING; RAS; PHOSPHOTYROSINE; CARCINOMA; RNA; IDENTIFICATION; ACTIVATION AB Using RNA fingerprinting (RAP) strategy and Northern blot analysis, we identified a differentially expressed sequence DOC-2 which is detectable in all normal human ovarian surface epithelial (HOSE) cell cultures but not in ovarian cancer cell lines and tissues. Subsequent cloning of DOC-2 from a cDNA library generated from the HOSE cells was carried out using the 3' and 5' RACE approach. A 3268 base pair full length cDNA of DOC-2 was isolated and sequenced. The predicted protein has a length of 770 amino acids. Homology search of all NCBI sequences indicated that the amino acid sequence of DOC-2 shares 93% homology with the mouse p96/mDab2 phosphoprotein and has a phosphotyrosine interacting domain (PID) and multiple SH3 binding motifs. Chromosomal localization by FISH showed that the DOC-2 gene is located on 5p13. Western blot analysis showed that the 105 kDa DOC-2 protein was down-regulated in all the carcinoma cell lines. In-situ immunohistochemistry performed on normal ovaries, and benign, borderline and invasive ovarian tumor tissues showed down regulation of DOC-2 protein particularly in serous ovarian tumor tissues. When DOC-2 was transfected into the ovarian carcinoma cell line SKOV3, the stable transfectants showed significantly reduced growth rate and ability to form tumors in nude mice. These data suggest that down-regulation of DOC-2 may play an important role in ovarian carcinogenesis. C1 Harvard Univ, Brigham & Womens Hosp, Sch Med,Dept Obstet Gynecol & Reprod Biol, Div Gynecol Oncol,Lab Gynecol Oncol, Boston, MA 02115 USA. Chinese Univ Hong Kong, Dept Anat, Shatin, Peoples R China. Pacific NW Lab, Richland, WA 99352 USA. Baylor Coll Med, Dept Pediat, Houston, TX 77030 USA. Baylor Coll Med, Dept Mol & Human Genet, Houston, TX 77030 USA. St Jude Childrens Res Hosp, Dept Biochem, Memphis, TN 38101 USA. RP Mok, SC (reprint author), Harvard Univ, Brigham & Womens Hosp, Sch Med,Dept Obstet Gynecol & Reprod Biol, Div Gynecol Oncol,Lab Gynecol Oncol, Boston, MA 02115 USA. RI genes, anthony/F-2541-2012; OI Wong, Kwong-Kwok/0000-0002-0375-6669 FU NCI NIH HHS [R01CA63381, R01CA69291, R01CA69453] NR 31 TC 121 Z9 127 U1 0 U2 4 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD MAY 7 PY 1998 VL 16 IS 18 BP 2381 EP 2387 DI 10.1038/sj.onc.1201769 PG 7 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA ZL389 UT WOS:000073428000010 PM 9620555 ER PT J AU Frabetti, PL Cheung, HWK Cumalat, JP Dallapiccola, C Ginkel, JF Johns, WE Nehring, MS Vaandering, EW Butler, JN Cihangir, S Gaines, I Garbincius, PH Garren, L Gourlay, SA Harding, DJ Kasper, P Kreymer, A Lebrun, P Shukla, S Vittone, M Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Culbertson, R Gardner, RW Gottschalk, E Greene, R Park, K Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L Di Corato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Meroni, E Milazzo, L Moroni, L Pedrini, D Perasso, L Prelz, F Sala, A Sala, S Torretta, D Buchholz, D Claes, D Gobbi, B O'Reilly, B Bishop, JM Cason, NM Kennedy, CJ Kim, GN Lin, TF Puseljic, DL Ruchti, RC Shephard, WD Swiatek, JA Wu, ZY Arena, V Boca, G Bonomi, G Castoldi, C Gianini, G Merlo, M Ratti, SP Riccardi, C Viola, L Vitulo, P Lopez, A Mendez, L Mirles, A Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Link, JM Paolone, VS Yager, PM Wilson, JR Gao, J Hosack, M Sheldon, PD Davenport, F Cho, K Danyo, K Handler, T Cheon, BG Chung, YS Kang, JS Kim, KY Lee, KB Myung, SS AF Frabetti, PL Cheung, HWK Cumalat, JP Dallapiccola, C Ginkel, JF Johns, WE Nehring, MS Vaandering, EW Butler, JN Cihangir, S Gaines, I Garbincius, PH Garren, L Gourlay, SA Harding, DJ Kasper, P Kreymer, A Lebrun, P Shukla, S Vittone, M Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Culbertson, R Gardner, RW Gottschalk, E Greene, R Park, K Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L Di Corato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Meroni, E Milazzo, L Moroni, L Pedrini, D Perasso, L Prelz, F Sala, A Sala, S Torretta, D Buchholz, D Claes, D Gobbi, B O'Reilly, B Bishop, JM Cason, NM Kennedy, CJ Kim, GN Lin, TF Puseljic, DL Ruchti, RC Shephard, WD Swiatek, JA Wu, ZY Arena, V Boca, G Bonomi, G Castoldi, C Gianini, G Merlo, M Ratti, SP Riccardi, C Viola, L Vitulo, P Lopez, A Mendez, L Mirles, A Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Link, JM Paolone, VS Yager, PM Wilson, JR Gao, J Hosack, M Sheldon, PD Davenport, F Cho, K Danyo, K Handler, T Cheon, BG Chung, YS Kang, JS Kim, KY Lee, KB Myung, SS CA E687 Collaboration TI Observation of a narrow state decaying into Xi(c) (0)pi(+) SO PHYSICS LETTERS B LA English DT Article ID BARYONS; CHARM; STRANGENESS AB We report the observation of the Xi(c)(*+) state decaying into Xi(c)(0)pi(+) with Xi(c)(0 )-->( )Lambda (K) over bar(0)pi(+)pi(-) or Lambda K(-)pi(+)pi(+)pi(-). We have observed 47 +/- 11 candidate events for the Xi(c)(*+) state and measured its mass to be 177.1 +/- 0.5 +/- 1.1 MeV/c(2) above the Xi(c)(0) mass. We have also measured the Xi(c)(0) mass to be 2470.0 +/- 2.8 +/- 2.6 MeV/c(2). (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Bologna, Dipartmento Fis, I-40126 Bologna, Italy. INFN, I-40126 Bologna, Italy. Univ Colorado, Boulder, CO 80309 USA. Fermilab, Batavia, IL 60510 USA. INFN, Nazl Frascati Lab, I-00044 Frascati, Italy. Univ Illinois, Urbana, IL 61801 USA. Univ Milan, Dipartmento Fis, I-20133 Milan, Italy. INFN, I-20133 Milan, Italy. Northwestern Univ, Evanston, IL 60208 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Univ Pavia, Dip Fis Nucl & Teor, I-27100 Pavia, Italy. INFN, I-27100 Pavia, Italy. Univ Puerto Rico, Mayaguez, PR USA. Univ Calif Davis, Davis, CA 95616 USA. Univ S Carolina, Columbia, SC 29208 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ N Carolina, Asheville, NC 28804 USA. Univ Tennessee, Knoxville, TN 37996 USA. Korea Univ, Seoul 136701, South Korea. RP Frabetti, PL (reprint author), Univ Bologna, Dipartmento Fis, I-40126 Bologna, Italy. RI Bonomi, Germano/G-4236-2010; Link, Jonathan/L-2560-2013 OI Bonomi, Germano/0000-0003-1618-9648; Link, Jonathan/0000-0002-1514-0650 NR 17 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 7 PY 1998 VL 426 IS 3-4 BP 403 EP 410 DI 10.1016/S0370-2693(98)00348-7 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZV357 UT WOS:000074296500024 ER PT J AU Xiao, ZG Lavery, MJ Ayhan, M Scrofani, SDB Wilce, MCJ Guss, JM Tregloan, PA George, GN Wedd, AG AF Xiao, ZG Lavery, MJ Ayhan, M Scrofani, SDB Wilce, MCJ Guss, JM Tregloan, PA George, GN Wedd, AG TI The rubredoxin from Clostridium pasteurianum: Mutation of the iron cysteinyl ligands to serine. Crystal and molecular structures of oxidized and dithionite-treated forms of the Cys42Ser mutant SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Review ID X-RAY-ABSORPTION; NUCLEAR-MAGNETIC-RESONANCE; SQUARE-WAVE VOLTAMMETRY; ARCHAEON PYROCOCCUS-FURIOSUS; MULTIPLE QUANTUM NMR; ESCHERICHIA-COLI; SULFUR PROTEIN; 4FE-4S CLUSTER; DESULFOVIBRIO-GIGAS; ELECTRON-TRANSFER AB Isolation is reported of the four mutant proteins of the electron-transfer protein rubredoxin from Clostridium pasteurianum in which each of the four cysteine ligands is changed in turn to serine. They fall into two pairs whose properties depend on whether an interior (C6, C39) or a surface (C9, C42) cysteine ligand is substituted. A crystal structure of the oxidized C42S protein (1.65 Angstrom; R, 18.5%) confirms the presence of an Fe-III(Sv-Cys)(3)(O-gamma-Ser) center (Fe-O, 1.82(8) Angstrom). Significant structural change is restricted to the region around the mutation. EXAFS experiments confirm (FeS3O)-S-III (O = O-gamma-Ser or OHx) centers in each oxidized protein at pH 8. The reduction potentials of the Fe-III/II couple are decreased by about 100 and 200 mV, respectively, in the interior and surface ligand mutants. The potentials are pH-dependent with respective pK(a)(red) values of about 9 and 7. EXAFS data indicate an increase of 0.2-0.3 Angstrom in the Fe-II-O distances in passing through these characteristic pK(a)(red) values. H-1 NMR experiments on Cd-II forms, reveal the presence of Cd-II-(S-Cys)(3)(O(H)-Ser) centers in the surface ligand mutants C9S and C42S by the detection of Cd-113-O-CH2beta coupling and S-OHgamma resonances. The assumption of the presence of Fe-II(S-Cys)(3)(O-Ser) centers in each mutant protein at pH values above the characteristic pK(a)(red) allows a simple interpretation Of the electrochemical behavior. Protonation of the Fe-O-gamma-Ser link upon reduction is proposed, followed by hydrolysis at lower pH values: Fe-III-O-gamma-Ser + H+ + e(-) --> Fe-II-O-gamma(H)-Ser; Fe-II-O-gamma(H)-Ser + H2O --> Fe-II-OH2 + HOgamma-Ser. The differences in reduction potentials, their pH-dependence, and the onset of irreversible electrochemistry can be attributed to differences in the Fe-O bonds of the interior and surface ligands. These differences appear to result from variation in the conformational flexibility of the protein chelate loops which carry the ligands. An attempt to generate crystals of the reduced Fe-II-C42S protein by treatment of Fe-III-C42S crystals with dithionite at pH 4 led to loss of iron. A crystal structure (1.6 Angstrom; R, 16.8%) reveals that cysteine residues 6 and 9 have trapped the oxidation product SO2, a result confirmed by reactions in solution: Cys-SH + SO2 --> Cys-S-II-(SO2-)-O-IV + H+. C1 Univ Sydney, Dept Biochem, Sydney, NSW 2006, Australia. Univ Melbourne, Sch Chem, Parkville, Vic 3052, Australia. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Wedd, AG (reprint author), Univ Sydney, Dept Biochem, Sydney, NSW 2006, Australia. EM M.Guss@biochem.usyd.edu.au; T.Wedd@chemistry.unimelb.edu.au RI Guss, Jules/B-1283-2009; Maher, Megan/B-2239-2012; George, Graham/E-3290-2013 OI Guss, Mitchell/0000-0003-4259-6079; Xiao, Zhiguang/0000-0001-6908-8897; NR 113 TC 55 Z9 56 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 6 PY 1998 VL 120 IS 17 BP 4135 EP 4150 DI 10.1021/ja973162c PG 16 WC Chemistry, Multidisciplinary SC Chemistry GA ZM476 UT WOS:000073544000012 ER PT J AU Gupta, JA Singh, MA Salomons, GJ Foran, WA Capel, MS AF Gupta, JA Singh, MA Salomons, GJ Foran, WA Capel, MS TI Small-angle X-ray scattering study of the microphase separation transition in asymmetric diblock copolymers: A model "B" kinetic phenomenon SO MACROMOLECULES LA English DT Article ID ORDER-DISORDER TRANSITION; BLOCK POLYMER-SOLUTIONS; SPINODAL DECOMPOSITION; POLYISOPRENE; POLYSTYRENE; NUCLEATION; BEHAVIOR; DYNAMICS; SYSTEMS AB We report the results of a time-resolved small-angle X-ray scattering (SAXS) study of the kinetics of the microphase separation transition in asymmetric styrene-butadiene diblock copolymers in semidilute solution. Following a quench to below the transition temperature, the scattered intensity at early stages is found to increase exponentially with time according to a time-dependent Ginzburg-Landau (TDGL) model, model "B" in the Hohenberg-Halperin notation. Over a range of scattering vectors near the SAXS peak, the exponential rate constants are modeled using the TDGL theory. The form of the wavevector dependence of the measured rate constants is used to test the fundamental predictions of the TDGL model. No lower and upper critical wavevectors are identified, although valid results for the static parameters are provided within the context of the model. C1 Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Singh, MA (reprint author), Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. NR 32 TC 7 Z9 7 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 5 PY 1998 VL 31 IS 9 BP 3109 EP 3115 DI 10.1021/ma971479r PG 7 WC Polymer Science SC Polymer Science GA ZM216 UT WOS:000073516300054 ER PT J AU Lillo, TM Van Siclen, CD Wright, RN AF Lillo, TM Van Siclen, CD Wright, RN TI Solute redistribution by a migrating grain boundary SO SCRIPTA MATERIALIA LA English DT Article ID DIFFUSION; MECHANISM C1 Lockheed Martin Idaho Technol, Idaho Falls, ID 83415 USA. RP Lillo, TM (reprint author), Lockheed Martin Idaho Technol, POB 1625, Idaho Falls, ID 83415 USA. OI Lillo, Thomas/0000-0002-7572-7883 NR 16 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAY 5 PY 1998 VL 38 IS 11 BP 1659 EP 1667 DI 10.1016/S1359-6462(98)00094-3 PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ZQ064 UT WOS:000073817800008 ER PT J AU Mercer, TW DiNardo, NJ Rothman, JB Siegal, MP Friedmann, TA Martinez-Miranda, LJ AF Mercer, TW DiNardo, NJ Rothman, JB Siegal, MP Friedmann, TA Martinez-Miranda, LJ TI Electron emission induced modifications in amorphous tetrahedral diamondlike carbon SO APPLIED PHYSICS LETTERS LA English DT Article ID FILMS AB The cold-cathode electron emission properties of amorphous tetrahedral diamondlike carbon are promising for flat-panel display and vacuum microelectronics technologies. The onset of electron emission is, typically, preceded by "conditioning" where the material is stressed by an applied electric field. To simulate conditioning and assess its effect, we combined the spatially localized field and current of a scanning tunneling microscope tip with high-spatial-resolution characterization. Scanning force microscopy shows that conditioning alters surface morphology and electronic structure. Spatially resolved electron-energy-loss spectroscopy indicates that the predominant bonding configuration changes from predominantly fourfold to threefold coordination. (C) 1998 American Institute of Physics. C1 Drexel Univ, Dept Phys & Atmospher Sci, Philadelphia, PA 19104 USA. Drexel Univ, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Mercer, TW (reprint author), MEMC Elect Mat Inc, St Peters, MO 63376 USA. EM mpsiega@sandia.gov NR 18 TC 49 Z9 49 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 4 PY 1998 VL 72 IS 18 BP 2244 EP 2246 DI 10.1063/1.121332 PG 3 WC Physics, Applied SC Physics GA ZK775 UT WOS:000073362300016 ER PT J AU Holmes, W Gildemeister, JM Richards, PL Kotsubo, V AF Holmes, W Gildemeister, JM Richards, PL Kotsubo, V TI Measurements of thermal transport in low stress silicon nitride films SO APPLIED PHYSICS LETTERS LA English DT Article ID BOLOMETERS AB We have measured the thermal conductance, G, of approximate to 1 mu m thick low stress silicon nitride membranes over the temperature range, 0.064 K, G is independent of surface condition indicating that the thermal transport is determined by bulk scattering. For T<4 K, scattering from membrane surfaces becomes significant. Membranes which have submicron sized Ag particles glued to the surface or are micromachined into narrow strips have a G that is reduced by a factor as large as 5 compared with that-of clean, solid membranes with the same ratio of cross section to length. (C) 1998 American Institute of Physics. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Conductus Inc, Sunnyvale, CA 94440 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Lockheed Martin Marietta, San Jose, CA 95134 USA. RP Holmes, W (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 21 TC 79 Z9 79 U1 2 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 4 PY 1998 VL 72 IS 18 BP 2250 EP 2252 DI 10.1063/1.121269 PG 3 WC Physics, Applied SC Physics GA ZK775 UT WOS:000073362300018 ER PT J AU Shan, W Ager, JW Walukiewicz, W Haller, EE Little, BD Song, JJ Schurman, M Feng, ZC Stall, RA Goldenberg, B AF Shan, W Ager, JW Walukiewicz, W Haller, EE Little, BD Song, JJ Schurman, M Feng, ZC Stall, RA Goldenberg, B TI Near-band-edge photoluminescence emission in AlxGa1-xN under high pressure SO APPLIED PHYSICS LETTERS LA English DT Article ID STRUCTURE LASER-DIODES; GALLIUM NITRIDE; NATIVE DEFECTS; GAN; OPERATION AB We present results of pressure-dependent photoluminescence (PL) studies of single-crystal AlxGa1-xN epitaxial films grown on sapphire substrates by metalorganic chemical vapor deposition. PL measurements were performed under hydrostatic pressure using the diamond-anvil-cell technique. PL spectra taken from the AlxGa1-xN epitaxial films are dominated by strong near-band-edge luminescence emissions. The emission lines were found to shift linearly towards higher energy with increasing pressure. By examining the pressure dependence of the spectral features, the pressure coefficients for the PL emissions associated with the direct Gamma band gap of AlxGa1-xN were determined. Our results yield a pressure coefficient of 4.0x10(-3) eV/kbar for Al0.05Ga0.95N and 3.6x10(-3) eV/kbar for Al0.35Ga0.65N. (C) 1998 American Institute of Physics. C1 Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Oklahoma State Univ, Ctr Laser & Photon Res, Stillwater, OK 74078 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. EMCORE Corp, Somerset, NJ 08873 USA. Honeywell Technol Ctr, Plymouth, MN 55420 USA. RP Shan, W (reprint author), Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. OI Ager, Joel/0000-0001-9334-9751 NR 17 TC 12 Z9 13 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 4 PY 1998 VL 72 IS 18 BP 2274 EP 2276 DI 10.1063/1.121277 PG 3 WC Physics, Applied SC Physics GA ZK775 UT WOS:000073362300026 ER PT J AU Lin, KC Holland, OW Feldman, LC Weitering, HH AF Lin, KC Holland, OW Feldman, LC Weitering, HH TI Surface characterization of silicon on insulator material SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE; SI(001); DEFECT AB The surface of ultrathin silicon on insulator (SOI) material has been characterized with surface science analysis techniques including atomic-resolution scanning tunneling microscopy. It is shown that the (100) SOI surface can be fabricated with a comparable degree of structural perfection as the (100) surface of bulk Si. Fermi level pinning by "type C" dimer defects results in a fully depleted and thus effectively insulating Si film. (C) 1998 American Institute of Physics. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. RP Weitering, HH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. EM hanno@utkux.utk.edu NR 12 TC 15 Z9 16 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 4 PY 1998 VL 72 IS 18 BP 2313 EP 2315 DI 10.1063/1.121346 PG 3 WC Physics, Applied SC Physics GA ZK775 UT WOS:000073362300039 ER PT J AU Song, XZ Jentzen, W Jaquinod, L Khoury, RG Medforth, CJ Jia, SL Ma, JG Smith, KM Shelnutt, JA AF Song, XZ Jentzen, W Jaquinod, L Khoury, RG Medforth, CJ Jia, SL Ma, JG Smith, KM Shelnutt, JA TI Substituent-induced perturbation symmetries and distortions of meso-tert-butylporphyrins SO INORGANIC CHEMISTRY LA English DT Article ID RESONANCE RAMAN-SPECTROSCOPY; PORPHYRIN FORCE-FIELD; LIGHT-ABSORPTION PROPERTIES; MOLECULAR MECHANICS; NICKEL OCTAETHYLPORPHYRIN; CRYSTAL-STRUCTURE; CYTOCHROMES-C; PHOTOSYNTHETIC CHROMOPHORES; NONPLANAR DISTORTION; ISOTOPE SHIFTS AB The out-of-plane and in-plane distortions of a series of nickel(II) meso-substituted porphyrins with 0, 1, 2, or 4 tert-butyl groups [nickel(II) porphine (NiP), nickel(II) mono-tert-butylporphyrin (NiMtBuP), nickel(TI) di-tert-butylporphyrin (NiDtBuP), and nickel(II) tetra-tert-butylporphyrin (NiTtBuP)] are investigated using molecular mechanics (MM) calculations, X-ray crystallography, UV-visible absorption spectroscopy, and resonance Raman spectroscopy. MM calculations are used to predict the stable conformations for this series of porphyrins. The out-of-plane distortions are then analyzed in terms of displacements along the normal coordinates of the porphyrin macrocycle using a new normal-coordinate structural decomposition method. As expected, the distortions are found to occur primarily along the lowest-frequency normal coordinate of each symmetry type and the distortions could be adequately simulated using only the lowest-frequency normal coordinates as a basis (the minimal basis). However, the distortions could be simulated significantly more accurately by extending the minimal basis by including the second-lowest-frequency normal coordinate of all symmetries. Using the extended basis is most important for the in-plane distortions. Detailed analysis of the types of distortion revealed that both the out-of-plane and the in-plane distortions depend on the perturbation symmetry of the peripheral substituents. The symmetry primarily depends on the pattern of substitution (number and positions of substituents) and the orientations of substituents. Often the perturbation symmetry can be predicted for a given porphyrin simply from the possible orientations of the substituents. Then, the main type(s) of symmetric deformation occurring for each possible molecular symmetry can be readily predicted from a D-4h correlation table. The stable conformers predicted by MM for the series of tert-butyl-substituted porphyrins confirm this simple but informative approach. Experimental verification of the calculated contributions of the symmetric deformations is provided by normal-coordinate structural decomposition of the available X-ray crystal structures of NiP, NiMtBuP, and NiDtBuP. The solid-state results are also supported by the resonance Raman and UV-visible absorption spectroscopic characterization of the porphyrins in solutions. The X-ray crystal structure of NiMtBuP is reported here for the first time. C1 Sandia Natl Labs, Mat Theory & Computat Dept, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Univ Essen Gesamthsch, Nukl Med Klin & Poliklin, D-45147 Essen, Germany. Univ Calif Davis, Dept Chem, Livermore, CA 95616 USA. RP Shelnutt, JA (reprint author), Sandia Natl Labs, Mat Theory & Computat Dept, POB 5800, Albuquerque, NM 87185 USA. RI Shelnutt, John/A-9987-2009; Smith, Kevin/G-1453-2011; Medforth, Craig/D-8210-2013; REQUIMTE, FMN/M-5611-2013; REQUIMTE, UCIBIO/N-9846-2013 OI Shelnutt, John/0000-0001-7368-582X; Smith, Kevin/0000-0002-6736-4779; Medforth, Craig/0000-0003-3046-4909; NR 56 TC 49 Z9 51 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 4 PY 1998 VL 37 IS 9 BP 2117 EP 2128 DI 10.1021/ic9711978 PG 12 WC Chemistry, Inorganic & Nuclear SC Chemistry GA ZM120 UT WOS:000073506700007 ER PT J AU Fishman, RS Shi, ZP AF Fishman, RS Shi, ZP TI Magnetic phase diagram of Fe/Cr multilayers and wedges SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID DENSITY-WAVE ANTIFERROMAGNETISM; ULTRATHIN CR FILMS; CHROMIUM-ALLOYS; SUPERLATTICES; FE(100) AB Based on a simple model with antiferromagnetic interactions at the Cr-Fe interfaces, we construct the magnetic phase diagram for the Cr spacer within Fe/Cr multilayers and wedges. The spin-density wave is found to undergo transitions between incommensurate (I) phases with a decreasing number of nodes n as the temperature increases for a fixed number N of Cr monolayers. In the limit N --> infinity, the incommensurate to commensurate (C) transition temperature from n = 1 to n = 0 nodes is independent of the Cr-Fe coupling strength but sensitively depends on the strain and doping. These results agree with recent neutron-scattering studies that the SDW inside Fe/Cr multilayers may be either C or I depending on the temperature and Cr thickness. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Read Rite Corp, R&D Div, Milpitas, CA 95035 USA. RP Fishman, RS (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Fishman, Randy/C-8639-2013 NR 20 TC 8 Z9 8 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 4 PY 1998 VL 10 IS 17 BP L277 EP L282 DI 10.1088/0953-8984/10/17/002 PG 6 WC Physics, Condensed Matter SC Physics GA ZM799 UT WOS:000073577000002 ER PT J AU Rutz, K Bender, M Reinhard, PG Maruhn, JA Greiner, W AF Rutz, K Bender, M Reinhard, PG Maruhn, JA Greiner, W TI Odd nuclei and single-particle spectra in the relativistic mean-field model SO NUCLEAR PHYSICS A LA English DT Article DE relativistic mean-field model; rmf; nuclear spin; single-particle levels; nuclear structure; odd nuclei; magic nuclei; excitation energies; time-reversal invariance; separation energies; shell gap; self-consistent; spin-orbit splitting; oxygen; calcium; nickel; tin; lead; uranium; core polarization; blocking approximation; delta force pairing; nuclear parity; correlations; effective interaction ID EVEN-EVEN NUCLIDES; MAGNETIC-MOMENTS; SHELL-MODEL; DYNAMICS; STATE; FORCES AB The relation between the single-nucleon spectra of doubly magic nuclei and the excitation energies of the neighboring odd nuclei is investigated within the framework of a relativistic mean-field model. Different levels of approximation (spherical, deformed with time-reversal invariance, without symmetry constraints) are computed and compared. Symmetry breaking, although small, has a substantial effect on separation energies and shell gaps. But energy differences completely within occupied or within unoccupied states are rather robust and can be safely estimated from the mere single-nucleon spectra of the even-even reference nucleus. (C) 1998 Elsevier Science B.V. C1 Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany. Gesell Schwerionenforsch GmbH, D-64291 Darmstadt, Germany. Univ Erlangen Nurnberg, Inst Theoret Phys, D-91058 Erlangen, Germany. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RP Rutz, K (reprint author), Univ Frankfurt, Inst Theoret Phys, Robert Mayer Str 10, D-60325 Frankfurt, Germany. RI Bender, Michael/B-9004-2009 NR 27 TC 81 Z9 81 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD MAY 4 PY 1998 VL 634 IS 1-2 BP 67 EP 88 DI 10.1016/S0375-9474(98)00153-5 PG 22 WC Physics, Nuclear SC Physics GA ZT785 UT WOS:000074125700005 ER PT J AU de Boer, J Hori, K Ooguri, H Oz, Y AF de Boer, J Hori, K Ooguri, H Oz, Y TI Kahler potential and higher derivative terms from M-theory fivebrane SO NUCLEAR PHYSICS B LA English DT Article DE M-theory fivebrane; supersymmetric gauge theories; Kahler potential; higher derivative terms AB The construction of four-dimensional supersymmetric gauge theories via the fivebrane of M-theory wrapped around a Riemann surface has been successfully applied to the computation of holomorphic quantities of field theory. In this paper we compute non-holomorphic quantities in the eleven-dimensional supergravity limit of M-theory. While the Kahler potential on the Coulomb of N = 2 theories is correctly reproduced, higher derivative terms in the N = 2 effective action differ from what is expected for the four-dimensional gauge theory. For the Kahler potential of N = 1 theories at an abelian Coulomb phase, the result again differs from what is expected for the four-dimensional gauge theory. Using a gravitational back-reaction method for the fivebrane we compute the metric on the Higgs branch of N = 2 gauge theories. Here we find an agreement with the results expected for the gauge theories. A similar computation of the metric on N = 1 Higgs branches yields information on the complex structure associated with the flavor rotation in one case and the classical metric in another. We discuss what four-dimensional field theory quantities can be computed via the fivebrane in the supergravity limit of M-theory. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, 366 LeConte Hall, Berkeley, CA 94720 USA. RI Ooguri, Hirosi/A-4407-2011 NR 64 TC 30 Z9 30 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 4 PY 1998 VL 518 IS 1-2 BP 173 EP 211 DI 10.1016/S0550-3213(98)00152-7 PG 39 WC Physics, Particles & Fields SC Physics GA ZP503 UT WOS:000073760000007 ER PT J AU Bartelt, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Ford, WT Gritsan, A Park, H Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Boisvert, V Cassel, DG Cho, HA Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Patton, S Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Azfar, F Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X AF Bartelt, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Ford, WT Gritsan, A Park, H Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Boisvert, V Cassel, DG Cho, HA Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Patton, S Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Azfar, F Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X TI Observation of the radiative decay D*+-> D+gamma SO PHYSICAL REVIEW LETTERS LA English DT Article ID E+E ANNIHILATIONS; MESON PRODUCTION; HEAVY QUARK; QCD; FRACTIONS; HADRONS AB We have observed a signal for the decay D*(+) --> D(+)gamma at a significance of 4 standard deviations. From the measured branching ratio B(D*(+) --> D(+)gamma)/B(D*(+) --> D(+)pi(0)) = 0.055 +/- 0.014 +/- 0.010 we find B(D*(+) --> D(+)gamma) = 0.017 +/- 0.004 +/- 0.003, where the first uncertainty is statistical and the second is systematic. We also report the highest precision determination of the remaining D*(+) branching fractions. C1 Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Ithaca Coll, Ithaca, NY 14850 USA. McGill Univ, Montreal, PQ H3A 2T8, Canada. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Texas, Austin, TX 78712 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. BINP, RU-630090 Novosibirsk, Russia. Yonsei Univ, Seoul 120749, South Korea. RP Bartelt, J (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA. RI Briere, Roy/N-7819-2014; OI Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674 NR 25 TC 15 Z9 15 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 3919 EP 3923 DI 10.1103/PhysRevLett.80.3919 PG 5 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800008 ER PT J AU de Bever, LJ Blok, HP Hicks, RS de Jager, CW Kalantar-Nayestanaki, N Kelly, JJ Lapikas, L Miskimen, RA Van Neck, D Peterson, GA van der Steenhoven, G de Vries, H AF de Bever, LJ Blok, HP Hicks, RS de Jager, CW Kalantar-Nayestanaki, N Kelly, JJ Lapikas, L Miskimen, RA Van Neck, D Peterson, GA van der Steenhoven, G de Vries, H TI Radial dependence of the nucleon effective mass in B-10 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-PARTICLE PROPERTIES; ELECTRON-SCATTERING; SHELL-MODEL; OCCUPATION PROBABILITIES; E'P REACTIONS; PB-208; E,E'P; DISTORTION; PROTONS AB The dynamic properties of the atomic nucleus depend strongly on correlations between the nucleons. We present a combined analysis of inelastic electron-scattering data and electron-induced proton knockout measurements in an effort to obtain phenomenological information on nucleon-nucleon correlations. Our results indicate that the ratio of radial wave functions extracted from precise B-10(e, e') and B-10(e, e'p) measurements evolve from an interior depression for small E-m, characteristic of short-range correlations, to a surface-peaked enhancement for larger E-m, characteristic of long-range correlations. This observation can be interpreted in terms of the nucleon effective mass. C1 NIKHEF H, Natl Inst Kernfys & Hoge Energiefys, NL-1009 DB Amsterdam, Netherlands. Univ Basel, Dept Phys & Astron, CH-4056 Basel, Switzerland. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Groningen, Kernfys Versneller Inst, NL-9747 AA Groningen, Netherlands. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Ghent, Dept Subatom & Radiat Phys, B-9000 Ghent, Belgium. RP de Bever, LJ (reprint author), NIKHEF H, Natl Inst Kernfys & Hoge Energiefys, POB 41882, NL-1009 DB Amsterdam, Netherlands. RI Kalantar-Nayestanaki, Nasser/A-3582-2016 OI Kalantar-Nayestanaki, Nasser/0000-0002-1033-7200 NR 30 TC 2 Z9 2 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 3924 EP 3927 DI 10.1103/PhysRevLett.80.3924 PG 4 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800009 ER PT J AU McCluskey, MD Johnson, NM Van de Walle, CG Bour, DP Kneissl, M Walukiewicz, W AF McCluskey, MD Johnson, NM Van de Walle, CG Bour, DP Kneissl, M Walukiewicz, W TI Metastability of oxygen donors in AlGaN SO PHYSICAL REVIEW LETTERS LA English DT Article ID PERSISTENT PHOTOCONDUCTIVITY; DX CENTERS; GAN; PHOTOLUMINESCENCE; SEMICONDUCTORS; ALXGA1-XAS; PRESSURE; ALLOYS; GAAS AB Experimental and theoretical evidence is presented for the metastability of oxygen donors in AlxGa1-xN. As the aluminum content increases, Hall effect measurements reveal an increase in the electron activation energy, consistent with the emergence of a deep DX level from the conduction band. Persistent photoconductivity is observed in Al0.39Ga0.61N:O at temperatures below 150 K after exposure to light, with an optical threshold energy of 1.3 eV. A configuration coordinate diagram is obtained from first-principles calculations and yields values for the capture barrier, emission barrier, and optical threshold which are in good agreement with the experimental results. C1 Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. Lawrence Berkeley Natl Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP McCluskey, MD (reprint author), Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. RI Van de Walle, Chris/A-6623-2012; Kneissl, Michael/B-9682-2012 OI Van de Walle, Chris/0000-0002-4212-5990; NR 26 TC 122 Z9 122 U1 5 U2 30 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4008 EP 4011 DI 10.1103/PhysRevLett.80.4008 PG 4 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800030 ER PT J AU Fernandez-Baca, JA Dai, P Hwang, HY Kloc, C Cheong, SW AF Fernandez-Baca, JA Dai, P Hwang, HY Kloc, C Cheong, SW TI Evolution of the low-frequency spin dynamics in ferromagnetic manganites SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; DOUBLE-EXCHANGE; LA1-XSRXMNO3; LA1-XCAXMNO3; RESISTIVITY AB Neutron scattering was used to study the ferromagnetic manganites Nd0.7Sr0.3MnO3 (T-C = 197.9 K) and PT0.63Sr0.37MnO3 (T-C = 300.9 K). The spin dynamical behavior of these two systems is similar at low temperatures but drastically different at temperatures around T-C. While the formation of spin clusters of size (similar to 20 Angstrom) dominates the spin dynamics of the 197.9 K sample close to T-C, the paramagnetic to ferromagnetic transition for the 300.9 K sample is mon conventional. These results, combined with seemingly inconsistent earlier reports, reveal clear systematics in the spin dynamics of the manganites. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. RP Fernandez-Baca, JA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Dai, Pengcheng /C-9171-2012; Hwang, Harold/I-6943-2012; Fernandez-Baca, Jaime/C-3984-2014; Kloc, Christian/A-2255-2011 OI Dai, Pengcheng /0000-0002-6088-3170; Fernandez-Baca, Jaime/0000-0001-9080-5096; NR 23 TC 141 Z9 142 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4012 EP 4015 DI 10.1103/PhysRevLett.80.4012 PG 4 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800031 ER PT J AU Mahan, GD Woods, LM AF Mahan, GD Woods, LM TI Multilayer thermionic refrigeration SO PHYSICAL REVIEW LETTERS LA English DT Article ID RESISTANCE AB A new method of refrigeration is proposed. Efficient cooling is obtained by thermionic emission of electrons over Schottky barriers between metals and semiconductors. Since the barriers have to be thin, each barrier can have only a small temperature difference (similar to 1 K). Macroscopic cooling is obtained with a multilayer device. The same device is also an efficient generator of electrical power. A complete analytic theory is provided. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Mahan, GD (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 22 TC 209 Z9 215 U1 6 U2 35 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4016 EP 4019 DI 10.1103/PhysRevLett.80.4016 PG 4 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800032 ER PT J AU Klimov, VI McBranch, DW AF Klimov, VI McBranch, DW TI Femtosecond 1P-to-1S electron relaxation in strongly confined semiconductor nanocrystals SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM DOTS; NONLINEAR TRANSMISSION; ENERGY-RELAXATION; LUMINESCENCE; MECHANISM; CLUSTERS; SPECTRUM AB High sensitivity femtosecond transient absorption is applied to directly measure the population-depopulation dynamics of the lowest (1S) and the first excited (1P) electron states in CdSe nanocrystals (NC's) of different radii with 1S-1P energy separation up to 16 longitudinal optical phonon energies. Instead of the drastic reduction of the energy relaxation rate expected due to a phonon bottleneck, we observe a fast subpicosecond 1P-to-1S relaxation, with the rate enhanced in NC's of smaller radius. This indicates the opening of new confinement-enhanced relaxation channels which likely involve Auger-type electron-hole energy transfer. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Klimov, VI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-6,MS-J585, Los Alamos, NM 87545 USA. NR 28 TC 304 Z9 305 U1 4 U2 55 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4028 EP 4031 DI 10.1103/PhysRevLett.80.4028 PG 4 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800035 ER PT J AU Hoover, WG Evans, DJ Posch, HA Holian, BL Morriss, GP AF Hoover, WG Evans, DJ Posch, HA Holian, BL Morriss, GP TI Comment on "Toward a statistical thermodynamics of steady states" SO PHYSICAL REVIEW LETTERS LA English DT Article ID NON-HAMILTONIAN SYSTEMS; IRREVERSIBILITY; ENTROPY C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Davis, Livermore, CA 94550 USA. Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia. Univ Vienna, A-1090 Vienna, Austria. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New S Wales, Sydney, NSW 2052, Australia. RP Hoover, WG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Evans, Denis/C-1653-2009 NR 11 TC 20 Z9 20 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4103 EP 4103 DI 10.1103/PhysRevLett.80.4103 PG 1 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800054 ER PT J AU Brooks, MSS Eriksson, O Wills, JM Johansson, B AF Brooks, MSS Eriksson, O Wills, JM Johansson, B TI Comment on "Density functional theory of crystal field quasiparticle excitations and the ab initio calculation of spin Hamiltonian parameters" - Brooks et al. reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Commiss European Communities, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, Germany. Univ Uppsala, Inst Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Brooks, MSS (reprint author), Commiss European Communities, Joint Res Ctr, Inst Transuranium Elements, Postfach 2340, D-76125 Karlsruhe, Germany. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 1 TC 0 Z9 0 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 4 PY 1998 VL 80 IS 18 BP 4108 EP 4108 DI 10.1103/PhysRevLett.80.4108 PG 1 WC Physics, Multidisciplinary SC Physics GA ZK808 UT WOS:000073365800058 ER PT J AU Fleming, JG Roherty-Osmun, E Smith, PM Custer, JS Kim, YD Kacsich, T Nicolet, MA Galewski, CJ AF Fleming, JG Roherty-Osmun, E Smith, PM Custer, JS Kim, YD Kacsich, T Nicolet, MA Galewski, CJ TI Growth and properties of W-Si-N diffusion barriers deposited by chemical vapor deposition SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Materials-Research-Society Meeting, Symposium K - Multilevel Metal Process Integration CY APR 01-02, 1997 CL SAN FRANCISCO, CALIFORNIA SP Mat Res Soc DE diffusion barrier; WSiN; refractory nitrides; CVD ID NITRIDE THIN-FILMS; TUNGSTEN NITRIDE; AMORPHOUS (MO; METALLIZATIONS; TA AB Films of W-Si-N were deposited by chemical vapor deposition, characterized, and compared to W-Si-N films deposited by physical vapor deposition, or sputtering. A range of different W-Si-N compositions were produced. The deposition temperature was low, 350 degrees C, and the precursors used are accepted by the semiconductor industry. Deposition rates are adequate for a diffusion barrier application. Resistivities range from 350 to 20,000 mu Omega cm, depending on composition. Step coverage of films with compositions expected to be of interest for diffusion barrier applications is 70-100% for aspect ratios of similar to 4 at similar to 0.25 mu, depending on composition. Films 1000 Angstrom thick with a composition W47Si9N44 were a effective barrier against Cu up to 700 degrees C. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. CALTECH, Pasadena, CA 91125 USA. RP Fleming, JG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 11 TC 29 Z9 32 U1 2 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 4 PY 1998 VL 320 IS 1 BP 10 EP 14 DI 10.1016/S0040-6090(97)01058-4 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA ZX451 UT WOS:000074517300002 ER PT J AU Ricco, AJ Crooks, RM AF Ricco, AJ Crooks, RM TI Chemical sensors SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Editorial Material C1 Sandia Natl Labs, Livermore, CA 94550 USA. Texas A&M Univ, College Stn, TX 77843 USA. RP Ricco, AJ (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. RI Ricco, Antonio/A-5273-2010 NR 1 TC 12 Z9 13 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 200 EP 200 DI 10.1021/ar980479o PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300002 ER PT J AU Crooks, RM Ricco, AJ AF Crooks, RM Ricco, AJ TI New organic materials suitable for use in chemical sensor arrays SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID SURFACE-CONFINED MONOLAYERS; PHASE PROBE MOLECULES; SELF-ASSEMBLED MONOLAYERS; ACOUSTIC-WAVE DEVICES; GOLD SURFACES; ALKANETHIOL MONOLAYERS; THIN-FILMS; SPECTROSCOPY; ADSORPTION; TIME C1 Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. Sandia Natl Labs, Microsensor R&D Dept, Albuquerque, NM 87185 USA. RP Crooks, RM (reprint author), Texas A&M Univ, Dept Chem, POB 300012, College Stn, TX 77842 USA. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 39 TC 218 Z9 222 U1 0 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 219 EP 227 DI 10.1021/ar970246h PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300005 ER PT J AU Okada, S Peng, S Spevak, W Charych, D AF Okada, S Peng, S Spevak, W Charych, D TI Color and chromism of polydiacetylene vesicles SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID THERMOCHROMIC PHASE-TRANSITION; LANGMUIR-BLODGETT-FILMS; DIACETYLENE SEGMENTED COPOLYMERS; STATE C-13 NMR; POLYMERIZED LIPOSOMES; OPTICAL-PROPERTIES; CONJUGATED POLYMERS; ORIENTED SYSTEMS; INFLUENZA-VIRUS; RESONANCE RAMAN C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Okada, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Ctr Adv Mat, Berkeley, CA 94720 USA. NR 69 TC 411 Z9 415 U1 13 U2 109 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 229 EP 239 DI 10.1021/ar970063v PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300006 ER PT J AU Ricco, AJ Crooks, RM Osbourn, GC AF Ricco, AJ Crooks, RM Osbourn, GC TI Surface acoustic wave chemical sensor arrays: New chemically sensitive interfaces combined with novel cluster analysis to detect volatile organic compounds and mixtures SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID ASSEMBLED COMPOSITE MONOLAYER; DEVICES; FILM; ELECTROPHORESIS; CONDUCTIVITY; DESIGN C1 Sandia Natl Labs, Microsensor R&D Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Dept Vis Sci, Albuquerque, NM 87185 USA. Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. RP Ricco, AJ (reprint author), Sandia Natl Labs, Microsensor R&D Dept, POB 5800, Albuquerque, NM 87185 USA. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 25 TC 111 Z9 111 U1 3 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 289 EP 296 DI 10.1021/ar9600749 PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300012 ER PT J AU Osbourn, GC Bartholomew, JW Ricco, AJ Frye, GC AF Osbourn, GC Bartholomew, JW Ricco, AJ Frye, GC TI Visual-empirical region-of-influence pattern recognition applied to chemical microsensor array selection and chemical analysis SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Osbourn, GC (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 8 TC 36 Z9 36 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 297 EP 305 DI 10.1021/ar970070j PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300013 ER PT J AU Agarwal, DA Moser, LE Melliar-Smith, PM Budhia, RK AF Agarwal, DA Moser, LE Melliar-Smith, PM Budhia, RK TI The Totem multiple-ring ordering and topology maintenance protocol SO ACM TRANSACTIONS ON COMPUTER SYSTEMS LA English DT Article DE lamport timestamp; network; partitioning; reliable delivery; topology maintenance; total ordering; virtual synchrony ID TOLERANT GROUP COMMUNICATION; SYSTEM; MULTICAST AB The Totem multiple-ring protocol provides reliable totally ordered delivery of messages across multiple local-area networks interconnected by gateways. This consistent message order is maintained in the presence of network partitioning and remerging, and of processor failure and recovery. The protocol provides accurate topology change information as part of the global total order of messages. It addresses the issue of scalability and achieves a latency that increases logarithmically with system size by exploiting process group locality and selective forwarding of messages through the gateways. Pseudocode for the protocol and an evaluation of its performance are given. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. Tandem Comp Inc, Cupertino, CA 95014 USA. RP Agarwal, DA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS 50B-2239, Berkeley, CA 94720 USA. EM daagarwal@lbl.gov; moser@ece.ucsb.edu; pmms@ece.ucsb.edu; budhia_ravi@ntos.tandem.com NR 24 TC 27 Z9 29 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0734-2071 J9 ACM T COMPUT SYST JI ACM Trans. Comput. Syst. PD MAY PY 1998 VL 16 IS 2 BP 93 EP 132 DI 10.1145/279227.279228 PG 40 WC Computer Science, Theory & Methods SC Computer Science GA 104AJ UT WOS:000074989800001 ER PT J AU Lebensohn, RA Wenk, HR Tome, CN AF Lebensohn, RA Wenk, HR Tome, CN TI Modelling deformation and recrystallization textures in calcite SO ACTA MATERIALIA LA English DT Article ID PLASTIC-DEFORMATION; ZIRCONIUM ALLOYS; STRAIN-PATH; POLYCRYSTALS; SHEAR; SIMULATION; LIMESTONE; FLOW AB A self-consistent polycrystal plasticity theory is applied to model the deformation and recrystallization behavior of rhombohedral calcite. In this mineral deformation occurs by slip and twinning and in experimentally deformed aggregates a strong crystallographic texture develops. Whereas the Taylor theory has failed to model axial compression, the self-consistent theory automatically introduces heterogeneous deformation by curling and simulates the correct texture. A deformation-based recrystallization model, that balances growth and nucleation, predicts a so far enigmatic high temperature texture. Aspects of mechanical twinning are also discussed. Many of the conclusions are directly applicable to other low-symmetry materials, especially hexagonal metals. (C) 1998 Acta Metallurgica Inc. C1 Univ Nacl Rosario, CONICET, Inst Fis Rosario, RA-2000 Rosario, Argentina. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Univ Nacl Rosario, CONICET, Inst Fis Rosario, 27 Febrero 210 Bis, RA-2000 Rosario, Argentina. RI Lebensohn, Ricardo/A-2494-2008; Tome, Carlos/D-5058-2013 OI Lebensohn, Ricardo/0000-0002-3152-9105; NR 33 TC 44 Z9 45 U1 2 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD MAY 1 PY 1998 VL 46 IS 8 BP 2683 EP 2693 DI 10.1016/S1359-6454(97)00477-1 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZP054 UT WOS:000073711900011 ER PT J AU Nieh, TG Hsiung, LM Wadsworth, J Kaibyshev, R AF Nieh, TG Hsiung, LM Wadsworth, J Kaibyshev, R TI High strain rate superplasticity in a continuously recrystallized Al-6%Mg-0.3%Sc alloy SO ACTA MATERIALIA LA English DT Article ID SC ALLOYS; MG ALLOY; AL; ALUMINUM; DUCTILITY; FLOW AB The superplastic properties of a cold-rolled Al-6Mg-0.3Sc alloy were studied at temperatures between 450 and 560 degrees C and strain rates between 10(-4) and 10(0) s(-1). The alloy was observed to exhibit super plasticity over wide temperature (475-520 degrees C) and strain rate ranges (similar to 10(-3)-10(-1) s(-1)). It was found that the addition of Sc to AI-Mg alloys resulted in a uniform distribution of fine coherent Al3Sc precipitates which effectively pinned subgrain and grain boundaries during static and dynamic recrystallization. In this paper, the microstructural evolution during superplastic deformation was systematically examined using both optical and transmission electron microscopy. Based upon this microstructural examination, a mechanism is proposed to explain the observed high strain rate superplasticity in the alloy. A model is also proposed that describes grain boundary sliding accommodated by dislocations gliding across grains containing coherent precipitates. (C) 1998 Acta Metallurgica Inc. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Inst Met Superplastic Problems, Ufa 450000, Bashkortostan, Russia. RP Nieh, TG (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-369,POB 808, Livermore, CA 94551 USA. RI LAI, JING/F-6526-2010; Nieh, Tai-Gang/G-5912-2011; Kaibyshev, Rustam/G-8804-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746; NR 28 TC 148 Z9 163 U1 5 U2 32 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 1 PY 1998 VL 46 IS 8 BP 2789 EP 2800 DI 10.1016/S1359-6454(97)00452-7 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZP054 UT WOS:000073711900020 ER PT J AU Dane, CB Hackel, LA Daly, J Harrison, J AF Dane, CB Hackel, LA Daly, J Harrison, J TI Shot peening with lasers SO ADVANCED MATERIALS & PROCESSES LA English DT Article C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Met Improvement Corp, Paramus, NJ 07652 USA. RP Dane, CB (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 5508, Livermore, CA 94550 USA. NR 0 TC 8 Z9 9 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD MAY PY 1998 VL 153 IS 5 BP 37 EP 38 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA ZL739 UT WOS:000073465600006 ER PT J AU Finnan, JM Jones, MB Burke, JI AF Finnan, JM Jones, MB Burke, JI TI A time-concentration study on the effects of ozone on spring wheat (Triticum aestivum L.). 3: Effects on leaf area and flag leaf senescence SO AGRICULTURE ECOSYSTEMS & ENVIRONMENT LA English DT Article DE ozone; spring wheat; senescence; chlorosis; soluble protein; leaf area ID OPEN-TOP CHAMBERS; WINTER-WHEAT; CV DRABANT; YIELD; PHOTOSYNTHESIS; LEAVES; GROWTH; EXPOSURE; IMPACT AB Spring sown wheat (Triticum aestivum L. cv. 'Promessa') was exposed to different concentrations of ozone in open-top chambers over a three year period at a site in the south-east of Ireland. Filtered and non-filtered treatments were used in addition to fumigated treatments in which additional ozone was added to the non-filtered air. Ozone was added either as short term high concentration exposures or as long term low concentration exposures. In 1991, exposure to the A+50 (Ambient+50 ppb ozone) treatment resulted in a substantial reduction in the green leaf area index and enhanced both the onset and the rate of leaf yellowing. The A+50 treatment in 1993 also resulted in a reduction in green leaf area in addition to accelerating chlorophyll and soluble protein loss in flag leaves. This treatment caused a more gradual loss of chlorophyll and green leaf area in comparison to the same treatment in 1991 which received a greater amount of potentially damaging ozone. In contrast the A+25 treatment in 1992 delayed leaf yellowing and enhanced green leaf retention in comparison to the filtered control treatment. This treatment received the same total cumulative ozone exposure as the A+50 treatment in 1991 but was supplied as a lower concentration over a longer time interval. High concentrations applied over short time intervals proved more phytotoxic than identical exposures in which lower concentrations were applied over longer time intervals. Changes in leaf senescence and in leaf area index induced by ozone were closely paralleled by changes in the grain yield. The results suggest that changes in grain yield are the result of ozone induced alterations in leaf senescence which lead to changes in the leaf area available for photosynthate production. (C) 1998 Elsevier Science B.V. All rights reserved. C1 TEAGASC, Oak Pk Res Ctr, Carlow, Ireland. Univ Dublin Trinity Coll, Dept Bot, Dublin 2, Ireland. RP Finnan, JM (reprint author), TEAGASC, Oak Pk Res Ctr, Carlow, Ireland. RI Finnan, John/D-1326-2016 NR 34 TC 20 Z9 21 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8809 J9 AGR ECOSYST ENVIRON JI Agric. Ecosyst. Environ. PD MAY PY 1998 VL 69 IS 1 BP 27 EP 35 DI 10.1016/S0167-8809(98)00088-7 PG 9 WC Agriculture, Multidisciplinary; Ecology; Environmental Sciences SC Agriculture; Environmental Sciences & Ecology GA ZQ779 UT WOS:000073902200004 ER PT J AU Wu, JZ Prausnitz, JM Firoozabadi, A AF Wu, JZ Prausnitz, JM Firoozabadi, A TI Molecular-thermodynamic framework for asphaltene-oil equilibria SO AICHE JOURNAL LA English DT Article ID HEAVY CRUDE OILS; CHEMICAL-STRUCTURE; PETROLEUM FLUIDS; VACUUM RESIDUE; PRECIPITATION; AGGREGATION; SOLVENTS; TEMPERATURE; DISSOLUTION; AMPHIPHILES AB Asphaltene precipitation is a perennial problem in producing and refining crude oils. To avoid precipitation, it is useful to know the solubility of asphaltenes in petroleum liquids as a function of temperature, pressure and liquid-phase composition. fit the novel molecular-thermodynamic framework presented here, both asphaltenes and resins are represented by pseudo-pure components while all other components in the solution are represented by a continuous medium that affects interactions among asphaltene and resin particles. The effect of the medium on asphaltene-asphaltene, resin-asphaltene, resin-resin pair interactions is taken into account through its density and dispersion-force properties. To obtain expressions for the chemical potential of asphaltene and Sor the osmotic pressure of an asphaltene-containing solution, the SAFT model is used in the framework of McMillan-Mayer theory, which considers hard-sphere repulsive association and dispersion-force interactions. By assuming that asphaltene precipitation is a liquid-liquid equilibrium process, a variety of experimental observations can bra explained including effects of temperature, pressure, and composition on the phase behavior of asphaltene-containing fluids. For practical quantitative applications, the model outlined here requires molecular parameters that must be estimated from a few Experimental data. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Reservoir Engn Res Inst, Palo Alto, CA 94304 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Firoozabadi, Abbas/C-5319-2011; Wu, Jianzhong/I-5164-2013; OI Wu, Jianzhong/0000-0002-4582-5941 NR 47 TC 107 Z9 109 U1 1 U2 15 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD MAY PY 1998 VL 44 IS 5 BP 1188 EP 1199 DI 10.1002/aic.690440516 PG 12 WC Engineering, Chemical SC Engineering GA ZM435 UT WOS:000073539900015 ER PT J AU Brandt, MT Levine, SP Smith, DG Ettinger, HJ AF Brandt, MT Levine, SP Smith, DG Ettinger, HJ TI Activity based cost management - Part I: Applied to occupational and environmental health organizations SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE activity-based cost management; activity-based costing; activity-based management; management; case study; environmental and occupational health AB The fundamental purpose of an environmental, safety, and health (ES&H) department or program-to assure worker health and safety and prevent environmental degradation-can be preserved by managers who can use contemporary business management tools to solve complex business and budgetary problems. Traditional cost accounting methods do not provide ES&H managers with the cost data and business process information required to make informed and timely decisions. Activity-based cost management (ABCM) is a business tool that can be used to quantify the cost of ES&H work activities and the cost of developing and delivering ES&H products and services. Additionally, the cost data and business process information that result from applying ABCM can be used to understand why these costs exist. The concepts, principles, and nomenclature associated with the two components of ABCM-activity-based costing (ABC) and activity-based management (ABM)-are discussed in this article, as is the utility of ABCM as a tool for managing ES&H departments and programs. C1 Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Los Alamos, NM 87545 USA. Univ Michigan, Sch Publ Hlth, WHO, Ctr Collaborat, Ann Arbor, MI 48109 USA. Erb Environm Management Inst, Ann Arbor, MI 48109 USA. Univ Michigan, Sch Publ Hlth, Dept Hlth Management & Policy, Ann Arbor, MI 48109 USA. RP Brandt, MT (reprint author), Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, POB 1663, Los Alamos, NM 87545 USA. NR 21 TC 2 Z9 3 U1 0 U2 1 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD MAY PY 1998 VL 59 IS 5 BP 328 EP 334 PG 7 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA ZR222 UT WOS:000073952500005 ER PT J AU Brandt, MT Levine, SP Smith, DG Ettinger, HJ Gallimore, BF AF Brandt, MT Levine, SP Smith, DG Ettinger, HJ Gallimore, BF TI Activity based cost management - Part II: Applied to a respiratory protection program SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE activity-based cost management; activity-based costing; activity-based management; cost modeling; environmental and occupational health AB To demonstrate the relevance of activity-based cost management (ABCM) for the occupational and environmental health community, the investigators used data generated by an ABCM model of a respiratory protection program (RPP) to develop options for solving a business problem. The RPP manager in this hypothetical but realistic business scenario is faced with a 25% budget cut and a 10% increase in demand for RPP services. The manager's dilemma is to maintain the integrity of the RPP while absorbing a significant budget cut. Various cost savings options are developed, and the assumptions under which these options operate are presented. It is emphasized that the RPP manager's primary responsibility is to assure worker health and safety by first understanding the technical issues, merits, and implications of any cost-cutting option that may be considered. It is argued that only then should the manager consider the financial merits of the possible solutions to this business problem. In this way worker health and safety, and environmental protection goals, can continue to be achieved in an economic climate of cost cutting and downsizing. C1 Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Los Alamos, NM 87545 USA. Erb Environm Management Inst, Ann Arbor, MI 48109 USA. Univ Michigan, Sch Publ Hlth, WHO, Ctr Collaborat, Ann Arbor, MI 48109 USA. Univ Michigan, Sch Publ Hlth, Dept Hlth Policy & Management, Ann Arbor, MI 48109 USA. RP Brandt, MT (reprint author), Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, POB 1663, Los Alamos, NM 87545 USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD MAY PY 1998 VL 59 IS 5 BP 335 EP 345 DI 10.1202/0002-8894(1998)059<0335:ACMPIA>2.0.CO;2 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA ZR222 UT WOS:000073952500006 PM 9622907 ER PT J AU Dreon, DM Fernstrom, HA Campos, H Blanche, P Williams, PT Krauss, RM AF Dreon, DM Fernstrom, HA Campos, H Blanche, P Williams, PT Krauss, RM TI Change in dietary saturated fat intake is correlated with change in mass of large low-density-lipoprotein particles in men SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Article DE diet; saturated fat; low-density lipoprotein subfractions; high-density lipoprotein; lipoprotein lipase; hepatic lipase; high-fat diet; low-fat diet; men ID CORONARY-ARTERY DISEASE; PLASMA TRIGLYCERIDE CONCENTRATION; HEPATIC LIPASE DEFICIENCY; APOLIPOPROTEIN-A-I; POSTHEPARIN PLASMA; SUBCLASS PATTERNS; HEART-DISEASE; SERUM-LIPIDS; FAMILIAL HYPERCHOLESTEROLEMIA; SELECTIVE MEASUREMENT AB We tested whether nutrient intakes estimated from 4-d diet records were associated with plasma lipoprotein subclasses in 103 men who were randomly assigned to a low-fat (24% fat) and a high-fat (46% fat) diet for 6 wk each in a crossover design. Postheparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities were also determined in a subset of 43 men. Changes in intake (ie, high fat minus low fat) of total saturated fatty acids, as well as myristic (14:0) and palmitic (16:0) acids, were positively correlated (P < 0.01) with increases in mass of large LDL particles [measured by analytic ultracentrifugation as mass of lipoproteins of flotation rate (S-f degrees) 7-12] and with LDL peak particle diameter and flotation rate, but not with changes in LDL-cholesterol concentration. Changes in total saturated fatty acids as well as myristic and palmitic acids were also inversely associated with changes in HL activity (P < 0.05). With the high-fat diet only, variation in dietary total saturated fatty acid intake was inversely correlated (P < 0.01) with concentrations of small, dense LDL of S-f degrees 0-5. This correlation was significant specifically for myristic acid (P < 0.001). Stearic acid (18:0), monounsaturates, and polyunsaturates showed no significant associations with lipoprotein concentrations. These data indicate that a high saturated fat intake (especially 14:0 and 16:0) is associated with increased concentrations of larger, cholesterol-enriched LDL and this occurs in association with decreased HL activity. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Dept Mol & Nucl Med, Donner Lab, Berkeley, CA 94720 USA. Childrens Hosp, Oakland Res Inst, Oakland, CA 94609 USA. RP Krauss, RM (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Dept Mol & Nucl Med, Donner Lab, Room 465,1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL-18574] NR 81 TC 80 Z9 85 U1 3 U2 8 PU AMER SOC CLINICAL NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, SUBSCRIPTIONS, RM L-3300, BETHESDA, MD 20814-3998 USA SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD MAY PY 1998 VL 67 IS 5 BP 828 EP 836 PG 9 WC Nutrition & Dietetics SC Nutrition & Dietetics GA ZK981 UT WOS:000073387000005 PM 9583838 ER PT J AU Eisele, GR Watkins, JP Matthews, KO AF Eisele, GR Watkins, JP Matthews, KO TI Workplace violence at government sites SO AMERICAN JOURNAL OF INDUSTRIAL MEDICINE LA English DT Article DE workplace violence; stalking; downsizing; stress; weapons; government employees; occupational medicine; trend ID HEALTH-CARE; STAFF; ASSAULTS; EMERGENCY; HOMICIDE; PATIENT; WORK AB A government agency and its contractors employing nearly 96,000 workers throughout the country was surveyed for documented incidents of violence in the workplace. Thirty-five occupational medicine and related professionals (36% of those surveyed) from 27 locations returned the questionnaire. Of the responders, 20 individuals reported 74 incidents of workplace violence, with nearly 30% of these occurrences involving weapons, including II with guns. In a companion survey of human resource departments from 28 locations, there were 16 responders (57% of those surveyed) with 13 of them documenting 96 additional incidents. No duplicate reporting of the same event occurred between the two surveys. Approximately 70% of the agency workers were employed in locations covered by the 51 responders. Although the data are limited, the number of incidents and level of violence appear to be increasing over time. Of the 108 incidents for which time of occurrence was known, 32 were defined as "very serious," which included physical assault, threat or assault with a weapon, murder suicide, or stalking. Verbal threats, verbal assaults, and vandalism were defined as "serious" incidents. A Cochran-Armitage trend test for an increasing proportion over time of "very serious" vs. "serious" events was statistically significant with a P-value of 0.026. (C) 1998 Wiley-Liss, Inc. C1 Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. US DOE, Off Occupat Med & Med Surveillance, Washington, DC USA. RP Eisele, GR (reprint author), Oak Ridge Inst Sci & Educ, POB 117, Oak Ridge, TN 37831 USA. NR 44 TC 10 Z9 10 U1 0 U2 3 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0271-3586 J9 AM J IND MED JI Am. J. Ind. Med. PD MAY PY 1998 VL 33 IS 5 BP 485 EP 492 DI 10.1002/(SICI)1097-0274(199805)33:5<485::AID-AJIM8>3.0.CO;2-R PG 8 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA ZE310 UT WOS:000072779800008 PM 9557172 ER PT J AU Foster, AL Brown, GE Tingle, TN Parks, GA AF Foster, AL Brown, GE Tingle, TN Parks, GA TI Quantitative arsenic speciation in mine tailings using X-ray absorption spectroscopy SO AMERICAN MINERALOGIST LA English DT Article ID FINE-STRUCTURE SPECTROSCOPY; MULTIPLE-SCATTERING; ADSORPTION; EXAFS; SCORODITE; COMPLEXES; SORPTION; SOILS; FERRIHYDRITE; FEASO4.2H2O AB X-ray absorption fine structure spectroscopy (XAFS) was used to determine arsenic (As) oxidation state, local coordination (to a radius of approximate to 7 Angstrom around As), and the relative proportion of different As species in model compounds and three California mine wastes: fully oxidized tailings (Ruth Mine), partially oxidized tailings (Argonaut Mine), and roasted sulfide ore (Spenceville Mine). Mineralogy was characterized by Rietveld refinement of X-ray powder diffraction patterns. The spatial distribution of As in the mine wastes (at several micrometers spatial resolution) was determined by electron microprobe analyses. X-ray absorption near edge structure (XANES) analysis indicates that As5+ is the dominant oxidation state in the mine samples, but mixed oxidation states (nominally As-0 and As5+) were observed in the Argonaut Mine waste. Non-linear, least-squares fits of mine waste EXAFS (Extended XAFS) spectra indicate variable As speciation in each of the three mine wastes: As5+, the Ruth Mine sample is sorbed on ferric oxyhydroxides and aluminosilicates (probably clay) in roughly equal portions. Tailings from the Argonaut Mine contain approximate to 20% As bound in arsenopyrite (FeAsS) and arsenical pyrite (FeS(2-x)Asx) and approximate to 80% As5+ in a precipitate such as scorodite (FeAsO4.2H(2)O); however, no precipitate was detected by X-ray diffraction or microprobe analysis, suggesting that the phase is poorly crystalline or has low abundance (total As in sample = 262 ppm). Roasted sulfide ore of the Spenceville Mine contains As5+ substituted for sulfate in jarosite [KFe3(SO4)(2)(OH)(6)] or incorporated in the structure of an unidentified Ca- or K-bearing phase, and As5+ sorbed to the surfaces of hematite or ferric oxyhydroxide grains. Determination of solid-phase As speciation in mine wastes by XAFS spectroscopy is a valuable first step in the evaluation of its bioavailability, because the mobility and toxicity of As compounds vary with oxidation state. As bound in precipitates, as in the Argonaut mine sample, is considered to be less available for uptake by organisms than when sorbed on mineral surfaces or coprecipitated with poorly crystalline phases, as found for the Ruth and Spenceville mine wastes. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Stanford Univ, Ctr Mat Res, Stanford, CA 94305 USA. RP Foster, AL (reprint author), Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. EM andrea@pangea.stanford.edu NR 64 TC 279 Z9 290 U1 8 U2 63 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 1998 VL 83 IS 5-6 BP 553 EP 568 PG 16 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA ZK140 UT WOS:000073289400016 ER PT J AU Gualtieri, A Artioli, G Passaglia, E Bigi, S Viani, A Hanson, JC AF Gualtieri, A Artioli, G Passaglia, E Bigi, S Viani, A Hanson, JC TI Crystal structure crystal chemistry relationships in the zeolites erionite and offretite SO AMERICAN MINERALOGIST LA English DT Article ID FRAMEWORK SILICATES; CHABAZITE; FAULTS AB This study clarifies the crystal structure variations and relationships in the zeolites erionite and offretite. The crystal structure analyses used Rietveld analysis of X-ray powder diffraction data, obtained both by synchrotron radiation and conventional X-ray sources, and on diffraction patterns obtained by transmission electron microscopy. The framework Al atoms in erionite are preferentially located in the single six-membered ring of tetrahedra (T2 site), whereas the Si-Al distribution is essentially disordered on the tetrahedral framework sites in offretite. In both zeolites, the center of the cancrinite cage is always occupied by K cations in similar amounts in both minerals. The erionite cage in erionite is occupied by Ca and Na atoms distributed on four distinct cation sites. Mg ions can be present up to 0.8 atoms per cell and are located between the Ca1 and Ca3 sites and very close to the Ca2 site on the symmetry axis. In offretite, the Mg site is located on the trigonal axis of the gmelinite cage and the Mg atoms are bonded to a variable number (five or six) of H2O molecules, depending on the site population. The structural data and TEM analysis clearly show that the crystal chemistry of the extraframework cations, Mg in particular, is a major factor controlling whether erionite or offretite crystallizes, the Si-Al distribution in the framework, and the possible stacking intergrowths of the two minerals. C1 Univ Modena, Dipartimento Sci Terra, I-41100 Modena, Italy. Univ Milan, Dipartimento Sci Terra, I-20133 Milan, Italy. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Gualtieri, A (reprint author), Univ Modena, Dipartimento Sci Terra, Via S Eufemia 19, I-41100 Modena, Italy. RI Hanson, jonathan/E-3517-2010; Viani, Alberto/H-2153-2014; Artioli, Gilberto/F-2149-2015; Gualtieri, Alessandro/L-9680-2015 OI Artioli, Gilberto/0000-0002-8693-7392; Gualtieri, Alessandro/0000-0002-4414-9603 NR 39 TC 31 Z9 32 U1 0 U2 1 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 1998 VL 83 IS 5-6 BP 590 EP 606 PG 17 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA ZK140 UT WOS:000073289400019 ER PT J AU Majidi, V Miller-Ihli, NJ AF Majidi, V Miller-Ihli, NJ TI Two simple interface designs for capillary electrophoresis inductively coupled plasma mass spectrometry SO ANALYST LA English DT Article; Proceedings Paper CT 3rd International Symposium on Speciation of Trace Elements in Biological, Environmental and Toxicological Sciences CY SEP 15-19, 1997 CL PORT DOUGLAS, AUSTRALIA SP Univ New S Wales, Natl Inst Occupat Hlth, McMaster Univ, Inst Environ & Hlth, MAFF, CSL, Food Sci Lab DE speciation; capillary electrophoresis; elemental analysis; elemental mass spectrometry; instrumentation ID MICROWAVE-INDUCED PLASMA; SPECIATION; SELENITE AB The design and implementation of two different interfaces for capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) are described. These interfaces will allow for on-line analysis of CE effluents with ICP-MS detection. One interface is based on a concentric tube nebulizer and the other on a standard cross-flow nebulizer, These systems were investigated in parallel and their performances, under various experimental conditions, were compared. Each interface possesses a unique set of advantages and shortcomings. Recognizing that typical sample flow rates for ICP-MS are of the order of mi min(-1) and that the flow rates for CE are a few nl min(-1), some difficulties in flow compatibility are encountered. Aspects discussed include interface considerations, flow compatibility and the influence of flow rates on the overall sensitivity. Several guidelines are provided for workers interested in implementing a CE-ICP-MS instrument for elemental speciation. The Cd detection limits in rabbit metallothionein were 2.36 and 0.21 mu g ml(-1) for the concentric and cross-flow nebulizers, respectively. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST9,MS K484, Los Alamos, NM 87545 USA. USDA ARS, Beltsville Agr Res Ctr, Beltsville Human Nutr Res Ctr, Food Composit Lab, Beltsville, MD 20705 USA. RP Majidi, V (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST9,MS K484, Los Alamos, NM 87545 USA. NR 20 TC 88 Z9 89 U1 1 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0003-2654 J9 ANALYST JI Analyst PD MAY PY 1998 VL 123 IS 5 BP 803 EP 808 DI 10.1039/a707770j PG 6 WC Chemistry, Analytical SC Chemistry GA ZN568 UT WOS:000073658900008 ER PT J AU Majidi, V Miller-Ihli, NJ AF Majidi, V Miller-Ihli, NJ TI Potential sources of error in capillary electrophoresis inductively coupled plasma mass spectrometry for chemical speciation SO ANALYST LA English DT Article; Proceedings Paper CT 3rd International Symposium on Speciation of Trace Elements in Biological, Environmental and Toxicological Sciences CY SEP 15-19, 1997 CL PORT DOUGLAS, AUSTRALIA SP Univ New S Wales, Natl Inst Occupat Hlth, McMaster Univ, Inst Environ & Hlth, MAFF, CSL, Food Sci Lab DE speciation; capillary electrophoresis; elemental mass spectrometry; cyanocobalamin; rabbit metallothionein; coenzyme-B-12 AB The distribution concentration of chemical species in a sample is dictated by the physical and chemical properties of the matrix. As such, when a sample is pre-treated, in any way, there is a potential for redistribution of homologous species. The extent of this analyte redistribution is determined by both thermodynamic properties of species (e.g., changes in concentrations of species according to their equilibrium expressions) and kinetic properties (e.g., the rate of the reactions compared with the duration of sample preparation and analysis). The redistributions of analyte species as a function of several experimental parameters (e.g., time, solution pH, injection methods and calibration methods) are illustrated in this paper, Whereas rabbit metallothionein protein showed a stability of more than a few days under certain storage conditions, coenzyme-B-12 was rapidly degraded in less than 2 h, pH studies showed that the migration of free Cd2+ ions in rabbit metallothionein was not significantly affected unless the pH of the solution exceeds the solubility limit of the metal hydroxide, However, pH-sensitive compounds such as vitamin B-12 showed significant changes in the migration time and analyte composition. The injection studies suggested that electrokinetic injection may produce biased results, in favor of species that have higher electrophoretic mobility. Hydrodynamic injection will produce a result that is more representative of the initial sample composition. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST9, Los Alamos, NM 87545 USA. USDA ARS, Beltsville Agr Res Ctr, Beltsville Human Nutr Res Ctr, Food Composit Lab, Beltsville, MD 20705 USA. RP Majidi, V (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST9, MS K484, Los Alamos, NM 87545 USA. NR 19 TC 38 Z9 38 U1 0 U2 3 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0003-2654 J9 ANALYST JI Analyst PD MAY PY 1998 VL 123 IS 5 BP 809 EP 813 DI 10.1039/a708256h PG 5 WC Chemistry, Analytical SC Chemistry GA ZN568 UT WOS:000073658900009 ER PT J AU Liu, CL Hofstadler, SA Bresson, JA Udseth, HR Tsukuda, T Smith, RD Snyder, AP AF Liu, CL Hofstadler, SA Bresson, JA Udseth, HR Tsukuda, T Smith, RD Snyder, AP TI On line dual microdialysis with ESI-MS for direct analysis of complex biological samples and microorganism lysates SO ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION-MASS-SPECTROMETRY; ASSISTED LASER DESORPTION/IONIZATION; LIQUID-CHROMATOGRAPHY; POLYACRYLAMIDE GELS; ELECTROSPRAY; PROTEINS; IDENTIFICATION; MATRIX; CELLS AB A novel dual-microdialysis approach has been developed for fast and efficient fractionation and cleanup for ESI-MS and ESI MS/MS analyses of biological samples. A modified dynamic microdialyzer utilizing two mirror-image serpentine channels, which sandwich a regenerated cellulose membrane of selected molecular weight cutoff, serves as the first stage for the removal of high-molecular-weight components and cellular residue. The second stage employs a hollow microdialysis capillary to remove low-molecular-weight species (e.g., salts) which can degrade or preclude analysis ESI-MS, A protein mixture consisting of 30 mu M bovine serum albumin (BSA), 4.0 mu M cytochrome c, 2.3 mu M ubiquitin, and 9.4 mu M bradykinin in 0.5 M NaCl was used to evaluate the performance of this system. Essentially complete removal of both BSA and NaCl was achieved, resulting in high-quality mass spectra containing only the lower molecular weight proteins. After passing through the on-line dual-microdialysis system, a crude bacteria cell lysate yielded clean ESI-mass spectra in similar to 20 min. MS/MS of selected ions demonstrated abundant fragment ions and provided a second-dimension "fingerprint" of the complex cellular fraction. Preliminary application of this technique for direct characterization of microorganism lysates is presented. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. USA, Edgewood Res, Ctr Dev & Engn, Aberdeen, Peoples R China. RP Smith, RD (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 24 TC 67 Z9 68 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1998 VL 70 IS 9 BP 1797 EP 1801 DI 10.1021/ac971193k PG 5 WC Chemistry, Analytical SC Chemistry GA ZL246 UT WOS:000073413400028 PM 9599580 ER PT J AU Ding, WL Fritz, JS AF Ding, WL Fritz, JS TI Separation of neutral compounds and basic drugs by capillary electrophoresis in acidic solution using laurylpoly(oxyethylene) sulfate as an additive SO ANALYTICAL CHEMISTRY LA English DT Article ID MICELLAR ELECTROKINETIC CHROMATOGRAPHY; ZONE ELECTROPHORESIS; ELECTROOSMOTIC FLOW; ORGANIC-MOLECULES; ENANTIOMERS; CYCLODEXTRINS; PEPTIDES; BUFFERS AB Working at pH 2.4 with uncoated silica capillaries has the advantage that electroosmotic now is virtually eliminated. Excellent separations of protonated organic bases were obtained when ethanesulfonic acid was added to the running electrolyte to coat the capillary surface by a dynamic equilibrium. The effect of adding a new surfactant, sulfonated Brij-30, to the acidic electrolyte was also investigated. Use of this surfactant in acidic organic-aqueous solutions changes the elution order of many organic cations and also permits the separation of neutral organic compounds. Excellent resolution of a mixture of 19 PAHs and similar compounds was obtained in 40% organic solvent in only 20 min. The largest organic compounds form the most stable association complexes with the sulfonated Brij-30 and, thus, have the shortest migration times. It is shown that the type and concentration of surfactant, as well as the composition of the aqueous-organic solution, are conditions that can be varied over a broad range to obtain superior separations of both neutral and cationic organic compounds. The type of organic solvent is yet another condition that can be manipulated advantageously. For example, the use of equal volumes of acetonitrile and 2-propanol in water-organic solutions can give better resolution of neutral organic analytes than either solvent used alone. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Fritz, JS (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. NR 31 TC 26 Z9 26 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1998 VL 70 IS 9 BP 1859 EP 1865 DI 10.1021/ac970883l PG 7 WC Chemistry, Analytical SC Chemistry GA ZL246 UT WOS:000073413400037 PM 21651277 ER PT J AU Ibrahim, MS Lofts, RS Jahrling, PB Henchal, EA Weedn, VW Northrup, MA Belgrader, P AF Ibrahim, MS Lofts, RS Jahrling, PB Henchal, EA Weedn, VW Northrup, MA Belgrader, P TI Real-time microchip PCR for detecting single-base differences in viral and human DNA SO ANALYTICAL CHEMISTRY LA English DT Article ID SMALLPOX; GENOME AB This report describes real-time 5' nuclease PCR assays to rapidly distinguish single-base polymorphism using a battery-powered miniature analytical thermal cycling instrument (MATCI). Orthopoxviruses and the human complement component C6 gene sewed as targets to demonstrate the feasibility of using the MATCI for diagnosis of infectious diseases and genetic disorders. In the Orthopoxvirus assay, consensus Orthopoxvirus PCR primers were designed to amplify 266-281 base-pair (bp) segments of the hemagglutinin (HA) gene in camelpox, cowpox, monkeypox, and vaccinia viruses. A vaccinia virus-specific fluorogenic (TaqMan) probe was designed to detect a single-base (A/G) substitution within the HA gene. In the C6 gene assay, a 73-bp segment of the C6 gene was PCR-amplified from human genomic DNA, and TaqMan probes were used to detect a single-base (A/C) polymorphism in the second position of codon 98. The MATCI correctly identified the nucleotide differences in both viral DNA and human genomic DNA, In addition, using a rapid DNA preparation method, it was possible to achieve sample, preparation of human genomic DNA, DNA amplification, and real-time detection in less than 1 h. C1 USA, Med Res Inst Infect Dis, Ft Detrick, MD 21702 USA. Armed Forces Radiobiol Res Inst, Bethesda, MD 20889 USA. Armed Forces Inst Pathol, Rockville, MD 20850 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Ibrahim, MS (reprint author), USA, MRIID, 1425 Porter St, Ft Detrick, MD 21701 USA. EM sibrahim@detrick.army.mil NR 17 TC 126 Z9 131 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1998 VL 70 IS 9 BP 2013 EP 2017 DI 10.1021/ac971091u PG 5 WC Chemistry, Analytical SC Chemistry GA ZL246 UT WOS:000073413400059 PM 9599592 ER PT J AU Zelicoff, AP AF Zelicoff, AP TI More on the most terrible of the ministers of death SO ANNALS OF INTERNAL MEDICINE LA English DT Letter C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Zelicoff, AP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU AMER COLL PHYSICIANS PI PHILADELPHIA PA INDEPENDENCE MALL WEST 6TH AND RACE ST, PHILADELPHIA, PA 19106-1572 USA SN 0003-4819 J9 ANN INTERN MED JI Ann. Intern. Med. PD MAY 1 PY 1998 VL 128 IS 9 BP 784 EP 785 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA ZK790 UT WOS:000073363800032 PM 9556486 ER PT J AU Kaufman, EN Harkins, JB Borole, AP AF Kaufman, EN Harkins, JB Borole, AP TI Comparison of batch-stirred and electro-spray reactors for biodesulfurization of dibenzothiophene in crude oil and hydrocarbon feedstocks SO APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY LA English DT Article DE oil desulfurization; Rhodococcus; electrostatic spraying; dibenzothiophene; biodesulfurization ID DESULFOVIBRIO-DESULFURICANS M6; EMULSION-PHASE CONTACTOR; MICROBIAL DESULFURIZATION; ORGANOSULFUR COMPOUNDS; SOLVENT-EXTRACTION; NONAQUEOUS MEDIA; SULFUR; SEPARATIONS; OXIDATION; BACTERIA AB Biological removal of organic sulfur from petroleum feedstocks offers an attractive alternative to conventional thermochemical treatment, because of the mild operating conditions afforded by the biocatalyst. in order for biodesulfurization to realize commercial success, reactors must be designed that allow for sufficient liquid-liquid and gas-liquid mass transfer, while simultaneously reducing operating costs. Electro-spray bioreactors were investigated for use as desulfurization reactors because of their reported operational cost savings relative to mechanically agitated reactors. Unlike batch-stirred reactors, which mix the biocatalyst-containing aqueous phase with the organic feedstock by imparting momentum to the entire bulk solution, electro-spray reactors have the potential for tremendous cost savings, creating an emulsion <5 mu m in diameter, at a cost of only 3 W/L. Power law relationships indicate that mechanically stirred reactors would require 100-1000-fold more energy to create such a fine emulsion, but these relationships generally do not account for the effect of endogenously produced surfactant in the system. Here, the rates dibenzothiophene (DBT) oxidation to 2-hydroxybiphenyl (2-HBP) in hexadecane, by Rhodococcus sp IGTS8 are compared in the two reactor systems. Desulfurization rates ranged from 1.0 to 5.0 mg 2-HBP/(dry g cells.h), independent of the reactor employed. The batch-stirred reactor was capable of forming a very fine emulsion in the presence of the biocatalyst IGTS8, similar to that formed in the emulsion phase contactor (EPC(TM)), presumably because the biocatalyst produces its own Surfactant. Although EPC did not prove to be advantageous for the IGTS8 desulfurization system, it may prove advantageous for systems that do not produce surface-active bioagents, in addition to being mass-transport limited. C1 Oak Ridge Natl Lab, Div Chem Technol, Bioproc Res & Dev Ctr, Oak Ridge, TN 37831 USA. RP Kaufman, EN (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Bioproc Res & Dev Ctr, Oak Ridge, TN 37831 USA. RI Borole, AP/F-3933-2011; Unciano, Noel/B-6810-2009; OI Borole, Abhijeet/0000-0001-8423-811X NR 43 TC 21 Z9 28 U1 1 U2 3 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USA SN 0273-2289 J9 APPL BIOCHEM BIOTECH JI Appl. Biochem. Biotechnol. PD MAY-JUN PY 1998 VL 73 IS 2-3 BP 127 EP 144 DI 10.1007/BF02785650 PG 18 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 124PG UT WOS:000076190400004 ER PT J AU Ma, R Zhao, X Yasumura, S Moore, RI Rarback, HM Dilmanian, FA Lomonte, AF Vodopia, KA Weber, DA Pierson, RN AF Ma, R Zhao, X Yasumura, S Moore, RI Rarback, HM Dilmanian, FA Lomonte, AF Vodopia, KA Weber, DA Pierson, RN TI Body-size corrections for in vivo neutron activation analysis SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Symposium on In Vivo Body Composition Studies CY SEP 18-20, 1996 CL MALMO, SWEDEN AB Differences in body size and shape can cause large variances in the results of in vivo neutron activation analysis. Preliminary body-size correction data were obtained for the delayed-gamma neutron activation facility (DGNA) at Brookhaven National Laboratory (BNL), based on phantom standards of different sizes, used in combination with computer simulations on the effect of different body sizes. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11794 USA. Univ Chicago, CARS, Chicago, IL 60637 USA. Univ Calif Davis, Dept Radiol, Sacramento, CA 95817 USA. St Lukes Roosevelt Hosp, Body Composit Unit, New York, NY 10025 USA. RP Ma, R (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11794 USA. FU NIDDK NIH HHS [P01-DK42618] NR 6 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY-JUN PY 1998 VL 49 IS 5-6 BP 531 EP 532 DI 10.1016/S0969-8043(97)00069-9 PG 2 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZE053 UT WOS:000072752700031 PM 9569535 ER PT J AU Ma, R Yasumura, S Moore, RI Zhao, X Rarback, HM Lomonte, AF Vodopia, KA AF Ma, R Yasumura, S Moore, RI Zhao, X Rarback, HM Lomonte, AF Vodopia, KA TI Total body chlorine: Calibration of the in vivo neutron activation measurement SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Symposium on In Vivo Body Composition Studies CY SEP 18-20, 1996 CL MALMO, SWEDEN AB Total body chlorine (TBCl), used to estimate the extracellular space, is measured by delayed-gamma neutron activation (DGNA) using the reaction Cl-37(n,gamma)Cl-38, at Brookhaven National Laboratory. During the calibration process, we noticed that different values were obtained when different amounts of Cl were placed in the phantom. This non-linear relationship is due tp the thermal neutron Aux suppression by the thermal neutron capture reaction Cl-35(n,gamma)Cl-36. Monte Carlo simulations confirm the results of phantom measurements showing an inverse relationship between the Cl content in the phantom and the gamma-ray yield per gram Cl. Thus, it is important to calibrate the DGNA system for TBCl using phantom standards containing an amount of Cl close to that expected in the individual undergoing measurement. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11794 USA. Univ Chicago, CARS, Chicago, IL 60637 USA. RP Ma, R (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11794 USA. FU NIDDK NIH HHS [P01-DK42618] NR 5 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY-JUN PY 1998 VL 49 IS 5-6 BP 533 EP 535 DI 10.1016/S0969-8043(97)00184-X PG 3 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZE053 UT WOS:000072752700032 PM 9569536 ER PT J AU Wang, ZM Deurenberg, P Ma, RM Kotler, D Heymsfield, SB AF Wang, ZM Deurenberg, P Ma, RM Kotler, D Heymsfield, SB TI Total body oxygen: Assessment from body weight and total body water SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Symposium on In Vivo Body Composition Studies CY SEP 18-20, 1996 CL MALMO, SWEDEN ID NEUTRON-ACTIVATION ANALYSIS C1 Columbia Univ, St Lukes Roosevelt Hosp, New York, NY 10027 USA. Agr Univ Wageningen, Dept Human Nutr, Wageningen, Netherlands. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Wang, ZM (reprint author), Columbia Univ, St Lukes Roosevelt Hosp, New York, NY 10027 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY-JUN PY 1998 VL 49 IS 5-6 BP 603 EP 605 DI 10.1016/S0969-8043(97)00080-8 PG 3 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZE053 UT WOS:000072752700052 PM 9569554 ER PT J AU Fountos, G Kounadi, E Tzaphlidou, M Yasumura, S Glaros, D AF Fountos, G Kounadi, E Tzaphlidou, M Yasumura, S Glaros, D TI The effects of inflammation-mediated osteoporosis (IMO) on the skeletal Ca/P ratio and on the structure of rabbit bone and skin collagen SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Symposium on In Vivo Body Composition Studies CY SEP 18-20, 1996 CL MALMO, SWEDEN AB The relationships between the skeletal Ca/P ratio (used as an index of bone quality) and structural changes in the bone and skin was studied in inflammatory mediated osteoporosis (IMO). The bone Ca/P ratio in IMO rabbits was significantly lower than in controls. Also, severe alterations were detected at the ultrastructural level in bone and skin collagen fibrils from IMO rabbits. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Ioannina, Sch Med, Dept Phys Med, Ioannina 45110, Greece. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Fountos, G (reprint author), Univ Ioannina, Sch Med, Dept Phys Med, Ioannina 45110, Greece. NR 5 TC 26 Z9 26 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY-JUN PY 1998 VL 49 IS 5-6 BP 657 EP 659 DI 10.1016/S0969-8043(97)00086-9 PG 3 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZE053 UT WOS:000072752700070 PM 9569570 ER PT J AU Yasumura, S Stamatelatos, IE Boozer, CN Moore, R Ma, R AF Yasumura, S Stamatelatos, IE Boozer, CN Moore, R Ma, R TI In vivo body composition studies in rats: Assessment of total body protein SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Symposium on In Vivo Body Composition Studies CY SEP 18-20, 1996 CL MALMO, SWEDEN ID NEUTRON-ACTIVATION AB The precision and accuracy of a prompt-gamma neutron activation facility developed to assess total body protein in rats is estimated. The coefficient of Variation of nitrogen measurement, as estimated by repeated measurements on 15 rats, was 5.5% for an equivalent dose of 60 mSv (Q = 20). Good agreement was observed in comparing the results of in vivo neutron activation analysis and chemical carcass analysis performed by the Kjeldahl method. The application of the technique in comparing the effect of a low-fat and a high-fat diet on body protein in rats is demonstrated. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Natl Ctr Sci Res Demokritos, Inst Nucl Technol & Radiat Protect, GR-15310 Athens, Greece. Columbia Univ, St Lukes Roosevelt Hosp, New York, NY 10025 USA. RP Yasumura, S (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. NR 6 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY-JUN PY 1998 VL 49 IS 5-6 BP 731 EP 732 DI 10.1016/S0969-8043(97)00209-1 PG 2 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZE053 UT WOS:000072752700094 PM 9569593 ER PT J AU Demas, JN Wu, M Goodwin, PM Affleck, RL Keller, RA AF Demas, JN Wu, M Goodwin, PM Affleck, RL Keller, RA TI Fluorescence detection in hydrodynamically focused sample streams: Reduction of diffusional defocusing by association of analyte with high-molecular-weight species SO APPLIED SPECTROSCOPY LA English DT Article DE luminescence analysis; hydrodynamic focusing; polymer; fluorescence; flow cytometry ID LASER-INDUCED FLUORESCENCE; SINGLE-MOLECULE; DNA; FLOW; CAPILLARY; ELECTROPHORESIS; PROBABILITY; MICROSCOPY; LIQUIDS AB Fluorescence methods have been developed for ultra-low-level detection down to the single molecule level, In ultra-low-level analysis, one successful approach to background reduction is to use hydrodynamically focused sample streams coupled with focused laser excitation to reduce detection volumes. However, low-molecular-weight analytes such as fluorescent dyes or fluorescently tagged nucleotides can diffuse radially out of the sample stream before detection, which can cause a significant reduction in the detection efficiency, Diffusional spreading can cause sample stream mixing in multiplexed analyses, Also, axial diffusion can cause misordering of analyte molecules in DNA sequencing at high analysis rates. A new method is presented for reducing diffusion effects by incorporating a high-molecular-weight species that has a strong binding affinity for the analyte (anchor) into the sheath fluid. As the analyte starts to diffuse out of the sample stream, it associates with the anchor and effectively assumes the anchor's molecular weight, This association reduces the analyte's mobility to that of the anchor. Consequently, both radial and axial diffusion are reduced. Further, in favorable cases, this adduct can have significantly increased luminescence yields and photostability compared to the free analyte, Examples of several dye polymer combinations involving electrostatic and other binding modes are given that show the very beneficial effects of this approach. Extension to other systems is described. C1 Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Demas, JN (reprint author), Univ Virginia, Dept Chem, Mccormick Rd, Charlottesville, VA 22901 USA. NR 49 TC 12 Z9 13 U1 0 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD MAY PY 1998 VL 52 IS 5 BP 755 EP 762 DI 10.1366/0003702981944184 PG 8 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA ZT028 UT WOS:000074040400020 ER PT J AU Fischer, DA Mitchell, GE Yeh, AT Gland, JL AF Fischer, DA Mitchell, GE Yeh, AT Gland, JL TI Functional group orientation in surface and bulk polystyrene studied by ultra soft X-ray absorption spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article DE polystyrene; X-ray absorption fine structure ID FILM SURFACES; EXCITATION-SPECTRA; DEPENDENCE; POLYIMIDE; POLYMERS AB The composition and orientation of functional groups at the surface and within the bulk of thin polystyrene films were studied by ultra soft X-ray absorption spectroscopy above the carbon K edge. The polystyrene films, which were produced by spin casting from solvents, were of varying thicknesses (1.5 to 100 nm) and molecular weights (3.8 kDa to 1000 kDa). Electron-yield and fluorescence-yield ultra soft X-ray absorption spectroscopy were used to probe simultaneously the surface (less than or equal to 3.6 nm) and the bulk (similar to 300 nm) of the polystyrene films. For the films studied, the pendant phenyl groups were found to be preferentially oriented toward the surface normal, independent of casting solvent, molecular weight, and film thickness. Additionally, the preferential orientation of the phenyl rings was slightly enhanced in the bulk versus the surface. The preferred orientation of the phenyl groups implies an orientation of the polymer backbone that is preferentially parallel to the surface of the films. The results indicate that the intramolecular forces may be more important than the intermolecular forces in determining polymer conformations at the surface and in bulk polystyrene. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Dow Chem Co, Analyt Sci Div, Midland, MI 48667 USA. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RP Fischer, DA (reprint author), Brookhaven Natl Lab, NIST PRT, Bldg 510E, Upton, NY 11973 USA. NR 21 TC 31 Z9 31 U1 4 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 133 IS 1-2 BP 58 EP 64 DI 10.1016/S0169-4332(98)00007-5 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZX205 UT WOS:000074489900008 ER PT J AU Knutsen, K Orlando, TM AF Knutsen, K Orlando, TM TI Low-energy (5-100 eV) electron-and ultraviolet (6.4 eV) photon-stimulated desorption of neutral fragments from NaNO(3) single crystals SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE photon-stimulated desorption; electron-stimulated desorption; NaNO(3); sodium nitrate ID SODIUM-NITRATE; EXCITATION; TRANSITION AB The low-energy (5-100 eV) electron-stimulated desorption (ESD) of neutrals from NaNO(3) single crystals is compared with 193 nm (6.4 eV) photon-stimulated desorption (PSD). The major ESD and PSD products, NO((2) Pi), and O((3)P), were detected via laser resonance enhanced multiphoton ionization. The less abundant NO(2) and O(2) products were detected only via quadrupole mass spectrometry. The ESD yields of NO((2) Pi) and O((3)P) show a linear dependence upon incident electron-beam current, indicating single-electron desorption events. The PSD yields of these fragments show a I-photon dependence on laser fluence, with no observable threshold down to 1 mu J/cm(2). For both ESD and PSD, the velocity distributions of NO((2) Pi) and O((3)P) have non-thermal components, consistent with near-surface dissociation events. We propose a mechanism for NO((2) Pi) and O((3)P) desorption which involves exciton production, localization and decay at the vacuum-surface interface. The NO(2) and O(2) velocity distributions are equilibrated to the 423 K surface temperature and the formation of these products may involve reactive scattering of O-atoms. since the neutral product yields and energy distributions are very similar for ESD and PSD, the final states involved in desorption must be similar. (C) 1998 Pacific Northwest National Laboratory. Published by Elsevier Science B.V. C1 Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Orlando, TM (reprint author), Pacific NW Lab, WR Wiley Environm Mol Sci Lab, POB 999,MS K8-88, Richland, WA 99352 USA. EM tm_orlando@pnl.gov NR 23 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 1 EP 6 DI 10.1016/S0169-4332(97)00604-1 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100002 ER PT J AU Russo, RE Geohegan, DB Haglund, RF Murakami, K AF Russo, RE Geohegan, DB Haglund, RF Murakami, K TI Laser ablation - Preface SO APPLIED SURFACE SCIENCE LA English DT Editorial Material C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Vanderbilt Univ, Nashville, TN USA. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Geohegan, David/D-3599-2013 OI Geohegan, David/0000-0003-0273-3139 NR 0 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP VII EP X PG 4 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100001 ER PT J AU Beck, KM Hess, WP AF Beck, KM Hess, WP TI Quantum-state resolved products via vacuum ultraviolet photostimulated desorption from geologic calcite SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE quantum-state resolved products; photostimulated desorption; geologic calcite ID ENHANCED MULTIPHOTON-IONIZATION; POSITIVE-ION EMISSION; STIMULATED DESORPTION; ALKALI-HALIDES; CO; EXCITATION; SURFACES; ATOM; MGO; DISTRIBUTIONS AB We report the results of a photostimulated desorption (PSD) study of neutral CO products from room temperature geologic calcite utilizing fluences < 300 mu J/cm(2) of 157-nm excimer laser radiation. At this wavelength, we are coincident with an intense absorption peak (absorption coefficient = 4.39 x 10(5) cm(-1)) such that most excitation occurs near or at the crystal surface. Detailed product state distributions are obtained using (2 + 1) resonance enhanced multiphoton ionization. The CO translational energy can be characterized by a temperature, T = 105 +/- 10 K, significantly lower than that of the substrate. The CO rotational and vibration state distributions appears thermalized to the surface. This maybe contrasted with our previous study of CO PSD from room temperature calcite done using 193-nm and 213-nm excitation. Bulk UV absorption decreases by two orders of magnitude at these wavelengths and excitation occurs throughout numerous bulk crystal layers. in those studies, CO translational energy could be characterized by a temperature of T = 110 K with product internal energy distributions which showed both thermal and non-thermal components. This seemed to indicate a rapid, scattered release from the surface. Broadly similar PSD results over a range of excitation wavelengths and crystal absorptivities confirms a final surface state decay mechanism in the production of product CO. Subtle variations may reflect state differences in desorption for excitations occurring near Or within the band gap and those occurring more deeply within the 'charge-transfer' band. (C) 1998 Elsevier Science B.V. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Beck, KM (reprint author), Pacific NW Lab, Environm Mol Sci Lab, K8-88, Richland, WA 99352 USA. EM km_beck@pnl.gov; wp_hess@pnl.gov NR 27 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 21 EP 25 DI 10.1016/S0169-4332(97)00606-5 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100004 ER PT J AU Taylor, DP Simpson, WC Knutsen, K Henderson, MA Orlando, TM AF Taylor, DP Simpson, WC Knutsen, K Henderson, MA Orlando, TM TI Photon stimulated desorption of cations from yttria-stabilized cubic ZrO(2)(100) SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; photon stimulated desorption; cubic zirconia ID SURFACES; EMISSION AB The positive ion yield resulting from the interaction of a pulsed 266-nm laser with yttria-stabilized cubic zirconia crystals is investigated. Although the photon energy (4.66 eV) is well below the nominal band-gap energy for ZrO(2) (5.0-5.5 eV), photon stimulated ion desorption (PSD) of Y(+), Zr(+), YO(+) and ZrO(+) begins at similar to 2.5 MW/cm(2). We interpret this as the onset of laser ablation. Cation mass spectra collected using higher laser fluences resemble those obtained via secondary-ion mass spectrometry (SIMS). The similarity between the laser ablation and SIMS data demonstrates the importance of surface electronic structure effects in photon induced degradation of this material. (C) 1998 Pacific Northwest National Laboratory. Published by Elsevier Science B.V. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Orlando, TM (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999,M-S K8-88, Richland, WA 99352 USA. EM tm_orlando@pnl.gov NR 13 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 101 EP 104 DI 10.1016/S0169-4332(97)00617-X PG 4 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100017 ER PT J AU Lippert, T Dickinson, JT Langford, SC Furutani, H Fukumura, H Masuhara, H Kunz, T Wokaun, A AF Lippert, T Dickinson, JT Langford, SC Furutani, H Fukumura, H Masuhara, H Kunz, T Wokaun, A TI Photopolymers designed for laser ablation - photochemical ablation mechanism SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE photopolymer; laser ablation; mechanism; excimer laser; triazenopolymer ID TRIAZENO-POLYMER; IRRADIATION; POLYIMIDE; DYNAMICS; FILM AB We have designed photopolymers based on a photolabile chromophore with absorption properties tailored for a specific irradiation wavelength. The introduction of the two photolabile groups (-N=N-N drop) into one repetition unit of the main polymer chain results in a well-defined decomposition pathway. The exothermic decomposition mechanism yields high energetic, gaseous products; which are not contaminating the polymer surface. The products of laser ablation were studied with time-of-flight mass spectroscopy (TOF-MS). All products are totally compatible with a photochemical decomposition mechanism and their high energies can be explained by a laser induced microexplosion. Time resolved techniques, such as transmission, reflectivity or surface interferometry, revealed a 'dynamic' behavior. Ns-interferometry showed that etching of the polymer nearly starts and ends with the laser pulse. During the initial stages of the irradiation, darkening of the surface was detected, which corresponds to a decrease of reflectivity and an increase of transmission. This is due to a decrease of the refractive index and absorption coefficient, caused by the photodecompostion of the polymer starting with the irradiation pulse. (C) 1998 Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Osaka Univ, Dept Appl Phys, Suita, Osaka 565, Japan. Paul Scherrer Inst, Dept Gen Energy Res, CH-5232 Villigen, Switzerland. RP Lippert, T (reprint author), Univ Calif Los Alamos Natl Lab, MS J 585, Los Alamos, NM 87545 USA. EM lippert@lanl.gov RI MASUHARA, Hiroshi/G-3148-2011; Fukumura, Hiroshi/G-4535-2011; Lippert, Thomas/N-2423-2016 NR 20 TC 16 Z9 16 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 117 EP 121 DI 10.1016/S0169-4332(97)00620-X PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100020 ER PT J AU Wood, RF Leboeuf, JN Chen, KR Geohegan, DB Puretzky, AA AF Wood, RF Leboeuf, JN Chen, KR Geohegan, DB Puretzky, AA TI Dynamics of plume propagation, splitting, and nanoparticle formation during pulsed-laser ablation SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE plume splitting; nanoparticle formation; pulsed-laser ablation ID MONTE-CARLO SIMULATIONS; DEPOSITION; GASES AB A new approach has been developed for modelling the expansion of laser-generated plumes into low pressure gases, where, initially, the mean free path may be long enough for interpenetration of the plume and background. Although relatively simple in structure, it gives excellent fits to new experimental data for Si in He and Ar, and provides for the first time a detailed, coherent explanation of the observed splitting of the plume into a fast and a slow component. The model is based on a combination of multiple elastic scattering and hydrodynamic formulations. The plume is broken into orders corresponding to the number of collisions made with the background. The first order reaches the detector without any scattering, the second order undergoes one scattering event, and so forth. While particles can only be transferred between the various orders by collisions, the densities in the individual orders propagate to give the overall plume expansion. The propagation is determined by the usual equations for the conservation of mass and momentum. Representative results from the calculations are presented, and the probable role of the background gas in nanoparticle formation is discussed. Published by Elsevier Science B.V. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Wood, RF (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 21 TC 69 Z9 69 U1 3 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 151 EP 158 DI 10.1016/S0169-4332(97)00625-9 PG 8 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100025 ER PT J AU Jeong, SH Greif, R Russo, RE AF Jeong, SH Greif, R Russo, RE TI Numerical modeling of pulsed laser evaporation of aluminum targets SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE pulsed laser evaporation; laser ablation; Knudsen layer ID GAS-DYNAMICS; VAPORIZATION; POLYMERS; SURFACE; METAL AB A one dimensional thermal model was used to investigate the pulsed laser evaporation of aluminum targets. The gasdynamic flow of the vapor was predicted by solving one dimensional compressible flow equations for an inviscid fluid. The variation of the threshold laser fluence for target evaporation with respect to target surface reflectivity was investigated. The threshold laser fluence predicted by a thermal evaporation model was larger than the values obtained experimentally. The effects of the ambient pressure and the laser fluence on the local Mach number of the vapor at the edge of the Knudsen layer were studied. The structure of the gasdynamic flow including the shock wave and the contact surface was shown in the density profiles. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM rerusso@lbl.gov NR 24 TC 33 Z9 33 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 177 EP 183 DI 10.1016/S0169-4332(97)00629-6 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100029 ER PT J AU Rubenchik, AM Feit, MD Perry, MD Larsen, JT AF Rubenchik, AM Feit, MD Perry, MD Larsen, JT TI Numerical simulation of ultra-short laser pulse energy deposition and bulk transport for material processing SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE hydrodynamics; laser; energy ID DIELECTRICS; NANOSECOND AB We have extended the physics of the one-dimensional radiation hydrodynamics simulation code HYADES to include processes important for studying laser-matter interaction with dielectrics and metals in the eV and sub-eV electron temperature range. Ultra-short laser pulses (USLP) are advantageous in many material processing situations where most of the absorbed laser energy appears in mass motion, and little appears as thermal energy. Major additions to the code include (1) the transport, reflection and absorption of laser light, (2) thermal energy transport and improved shockwave physics, and (3) improved models for the equation of state (EOS), strength of materials, and fracture. Examples from material processing and plasma generation were chosen for simulation. Our numerical simulations include the effects of radiation transport, hydrodynamic expansion and shockwave phenomena. (C) 1998 Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Cascade Appl Sci, Boulder, CO 80306 USA. RP Rubenchik, AM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,MS L-449, Livermore, CA 94550 USA. RI Feit, Michael/A-4480-2009 NR 6 TC 32 Z9 33 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 193 EP 198 DI 10.1016/S0169-4332(97)00631-4 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100031 ER PT J AU Mao, SS Mao, XL Greif, R Russo, RE AF Mao, SS Mao, XL Greif, R Russo, RE TI Simulation of infrared picosecond laser-induced electron emission from semiconductors SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE infrared picosecond laser-induced electron emission; semiconductors; silicon ID PULSES; THRESHOLD; DAMAGE AB In this study, we present a self-consistent model for picosecond laser induced electron emission from silicon. Surface electron emission due to a pulsed laser excitation originates from thermionic and photoelectric effects, both of which depend on the surface electron temperature and incident laser pulse intensity. By numerically solving a set of coupled transport equations, time dependent surface electron temperature as well as lattice temperature was determined. The electron emission rates and electron yields due to photoelectric and thermionic effects have been studied for varying pulse width and pulse intensity. For picosecond pulses at 1064 nm, the dominant emission mechanism was found to be photoelectric emission for pulse fluences below the melting threshold. In addition, a comparison between electron emission due to the picosecond infrared pulse and a picosecond 532 nm pulse was also presented. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Engn Mech, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 16 TC 36 Z9 36 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 206 EP 211 DI 10.1016/S0169-4332(97)00633-8 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100033 ER PT J AU Hess, WP Park, HK Yavas, O Haglund, RF AF Hess, WP Park, HK Yavas, O Haglund, RF TI IR-MALDI of low molecular weight compounds using a free electron laser SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE IR-MALDI; free electron laser; ethylenediaminetetraacetic acid (EDTA); nitrilotriacetic acid (NTA) AB Initial experiments on infrared matrix-assisted laser desorption/ionization mass spectrometry (IR-MALDI) using a free electron laser in the analysis of low-molecular-weight compounds are reported. Mass spectra from samples of ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) and a phosphate salt were obtained. Low molecular weight (LMW) compounds are of similar mass as the molecular weight of the matrix compound and interference between matrix and analyte ions can degrade MALDI sensitivity. Under optimal conditions, however, we find little interference and that often the analyte signal exceeds the matrix signal, a result also observed in UV-MALDI of these compounds, In the IR-MALDI of EDTA near 3.0 mu m the FEL results are similar to those obtained using a fixed frequency 2.94 mu m Er:YAG laser of 200 ns pulse duration. However. the tunable FEL laser can selectively excite particular vibrational modes of the matrix (e.g., an OH or CO stretch) or of residual water contained within the crystalline MALDI sample. This capability was used to explore possible vaporization and ionization mechanisms of IR-MALDI for EDTA. (C) 1998 Pacific Northwest National Laboratory. Published by Elsevier Science B.V. C1 Pacific NW Lab, Richland, WA 99352 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Vanderbilt Univ, WM Keck Fdn Free Electron Laser Ctr, Nashville, TN 37235 USA. RP Hess, WP (reprint author), Pacific NW Lab, POB 999,K8-88,3020 Q St, Richland, WA 99352 USA. EM wp_hess@pnl.gov; haglunrf@ctrvax.vanderbilt.edu NR 12 TC 23 Z9 23 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 235 EP 241 DI 10.1016/S0169-4332(97)00637-5 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100037 ER PT J AU Puretzky, AA Geohegan, DB AF Puretzky, AA Geohegan, DB TI LIF imaging and gas-phase diagnostics of laser desorbed MALDI-matrix plumes SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser-induced fluorescence; laser; plasma diagnostic technique ID IONIZATION MASS-SPECTROMETRY; DESORPTION; IONS; DISTRIBUTIONS; SPECTROSCOPY; ABLATION AB The first gated laser-induced fluorescence (LIF) imaging and absorption spectroscopy have been performed on laser desorbed plumes from organic crystals which are commonly used as MALDI (matrix assisted laser desorption ionization) matrices. These plasma diagnostic techniques, as well as ion probe measurements, were employed to investigate the desorbed products, densities, fractional ionization, and velocity distributions of the plume of ejecta which is typically encountered as the main desorption product in the mass spectrometry analysis of large biomolecules. Pulsed-ultraviolet (193 nm and 248 nm) desorption from 3-hydroxypicolinic acid (3-HPA) crystals was studied. Gas-phase absorption spectra of 3-HPA measured here revealed very different absorption cross-sections at these two wavelengths, and this was exploited to investigate the effects of plume absorption of the desorbing laser pulse. In both cases, LIF imaging revealed two plume components: a fast (maximum similar to 0.1 cm/mu s) low-intensity component which appear to be 3-HPA fragments, and a slower component of 3-HPA expanding at 0.05 cm/mu s. In the case of ArF-laser irradiation, optical absorption spectroscopy indicated a breaking of the intramolecular hydrogen bond in the gas-phase matrix material. (C) 1998 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Puretzky, AA (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 17 TC 16 Z9 16 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 248 EP 254 DI 10.1016/S0169-4332(97)00639-9 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100039 ER PT J AU Alexander, ML Smith, MR Hartman, JS Mendoza, A Koppenaal, DW AF Alexander, ML Smith, MR Hartman, JS Mendoza, A Koppenaal, DW TI Laser ablation inductively coupled plasma mass spectrometry SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser; wavelength; plasma ID ELEMENTAL ANALYSIS; SOLIDS AB Laser ablation inductively coupled plasma mass spectrometry (LA-ICP/MS) has been successfully deployed by researchers at the Pacific Northwest Laboratory for the analysis of Hanford nuclear waste. This effort required research to determine the relative importance of the numerous parameters involved in LA-ICP/MS. These factors include laser parameters and sample matrix variables. The precision in relative concentrations was determined as a function of laser wavelength. Ablation at 355 or 266 nm gave precision of 5-10%, while the value for 532 nm was 25% and for 1064 nm was 40%. Analysis of the data for relative fractionation between elements showed large differences in the IR for volatile vs. refractory elements. The UV ablation gave results that were much less dependent on matrix effects and showed minimal or no fractionation. Measurements of the particle distribution produced by laser ablation prior to transfer to the ICP/MS were made as a function of laser wavelength and pulse energy. These results show that the laser wavelength and pulse energies that provide the best precision and accuracy for analysis of glass or tank waste simulant materials produce particle size distributions with the majority of ablated material present as particles from 0.1-1.0 mu m in diameter. This size range is important for quantitative transport to the ICP/MS and for complete digestion of the particles in the plasma. The particle counts were used to normalize the mass spectra of glasses having widely different opacities and laser ablation efficiencies resulting in quantitative analysis of these samples. (C) 1998 Pacific Northwest National Laboratory. Published by Elsevier Science B.V. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Alexander, ML (reprint author), K8-93,3335 Q Ave, Richland, WA 99352 USA. EM ml_alexander@pnl.gov NR 17 TC 42 Z9 42 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 255 EP 261 DI 10.1016/S0169-4332(97)00640-5 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100040 ER PT J AU Mao, XL Ciocan, AC Borisov, OV Russo, RE AF Mao, XL Ciocan, AC Borisov, OV Russo, RE TI Laser ablation processes investigated using inductively coupled plasma atomic emission spectroscopy (ICP-AES) SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation mechanisms; spectral emission intensity; atomic line ratio; excitation temperature; multicomponent sample ID MASS-SPECTROMETRY; SOLID MATERIALS; SAMPLES; GLASS AB The symbiotic relationship between laser ablation mechanisms and analytical performance using inductively coupled plasma-atomic emission spectroscopy are addressed in this work. For both cases, it is important to ensure that the ICP conditions (temperature and electron number density) are not effected by the ablated mass. By ensuring that the ICP conditions are constant, changes in spectral emission intensity will be directly related to changes in laser ablation behavior. Mg ionic line to atomic line ratios and excitation temperature were measured to monitor the ICP conditions during laser-ablation sample introduction. The quantity of ablated mass depends on the laser pulse duration and wavelength. The quantity of mass removed per unit energy is larger when ablating with shorter laser wavelengths and pulses. Preferential ablation of constituents from a multicomponent sample was found to depend on the laser beam properties (wavelength and pulse duration). For nanosecond-pulsed lasers, thermal vaporization dominates the ablation process. For picosecond-pulsed lasers, a non-thermal mechanism appears to dominate the ablation process. This work will describe the mass ablation behavior during nanosecond and picosecond laser sampling into the ICP. The behavior of the ICP under mass loading conditions is first established, followed by studies of the ablation behavior at various power densities. A thermal vaporization model is used to explain nanosecond ablation, and a possible non-thermal mechanism is proposed to explain preferential ablation of Zn and Cu from brass samples during picosecond ablation. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM rerusso@lbl.gov NR 19 TC 33 Z9 34 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 262 EP 268 DI 10.1016/S0169-4332(97)00787-3 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100041 ER PT J AU Chan, WT Leung, APK Mao, XL Russo, RE AF Chan, WT Leung, APK Mao, XL Russo, RE TI Effects of gas environment on picosecond laser ablation SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; inductively coupled plasma (ICP); atomic emission spectroscopy (AES) ID INDUCTIVELY-COUPLED PLASMA; EMISSION; VAPORIZATION; SPECTROSCOPY; ATMOSPHERE AB The effect of gas medium on picosecond laser ablation at atmospheric pressure was studied for enhancing the quantity of mass removed. Five noble gases (He, Ne, Ar, Kr, Xe) were used in the ablation chamber and were found to influence the laser ablation efficiency significantly. The quantity of mass was measured using inductively coupled plasma (ICP) atomic emission spectroscopy (AES). Spectral emission intensity in the ICP is directly related to the quantity of mass ablated. The performance of laser ablation in different gases correlates with the ionization potential of the gas. There is an enhancement of emission intensity for laser sampling in He relative to Ar. Plasma shielding is discussed as a possible mechanism for the enhancement. (C) 1998 Elsevier Science B.V. C1 Univ Hong Kong, Dept Chem, Hong Kong, Peoples R China. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chan, WT (reprint author), Univ Hong Kong, Dept Chem, Pokfulam Rd, Hong Kong, Peoples R China. EM wtchan@hkusua.hku.hk; x_mao@lbl.gov; rerusso@lbl.gov NR 15 TC 12 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 269 EP 273 DI 10.1016/S0169-4332(97)00641-7 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100042 ER PT J AU Cheung, NH Ng, CW Ho, WF Yeung, ES AF Cheung, NH Ng, CW Ho, WF Yeung, ES TI Ultra-micro analysis of liquids and suspensions based on laser-induced plasma emissions SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE spectrochemical analysis of liquids and suspensions; pulsed-laser ablation; laser-induced plasma; single cell analysis ID VAPORIZATION; BREAKDOWN AB Spectrochemical analysis of liquids and suspensions using laser-induced plasma emissions was investigated. Nd:YAG pulsed-laser (532-nm) ablation of aqueous samples produced plasmas that were hot (few eV) and extensively ionized, with electron density in the 10(18) cm(-3) range. Analyte line signals were initially masked by intense plasma continuum emissions, and would only emerge briefly above the background when the plume temperature dropped below 1 eV during the course of its very rapid cooling. In contrast. 193-nm laser ablation at similar fluence generated plasmas of much lower (< 1 eV temperature but comparable electron density. The plasma continuum emissions were relatively weak and the signal-to-background ratio was a thousand times better. This 'cold' plasma was ideal for sampling trace amounts of biologically important elements such as sodium and potassium. By ablating hydrodynamically focused jets in a sheath-flow, and with acoustic normalization for improved precision, the single-shot detection limits of sodium and potassium were 8 and 50 fg, respectively. Using the sheath-flow arrangement, the amounts of sodium and potassium inside single human red blood cells were simultaneously determined for the first time. The intracellular contents for a given blood donor were found to vary significantly, with only very weak correlation between the amounts of sodium and potassium in individual cells. (C) 1998 Elsevier Science B.V. C1 Hong Kong Baptist Univ, Dept Phys, Hong Kong, Peoples R China. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Cheung, NH (reprint author), Hong Kong Baptist Univ, Dept Phys, Waterloo Rd, Hong Kong, Peoples R China. EM nhcheung@hkbu.edu.hk NR 8 TC 8 Z9 8 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 274 EP 277 DI 10.1016/S0169-4332(97)00642-9 PG 4 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100043 ER PT J AU Figg, DJ Cross, JB Brink, C AF Figg, DJ Cross, JB Brink, C TI More investigations into elemental fractionation resulting from laser ablation inductively coupled plasma mass spectrometry on glass samples SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; LA-ICP-MS; elemental fractionation; particle analysis ID RESPONSES AB Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) experiments have been performed to determine if any portion of the observed elemental fractionation from 532 nm ablation of glass samples occurs in the ICP. A tubing insert has been made to remove the larger sized particles from the transfer tubing before they reach the ICP-MS and particles counter. The advantages of the tubing insert is that the ablation parameters can be held constant while the particles size distribution is changed. The data suggest that indeed the ICP may contribute to elemental fractionation. It also suggest that the composition of the particles may vary with size. Evidence for a change in the ablation process at 10(9) W/cm(2) is also noted. The particle size distribution shifts, the slope of the analytes' MS response changes, and less elemental fractionation is observed beyond this irradiance threshold. (C) 1998 Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Figg, DJ (reprint author), Univ Calif Los Alamos Natl Lab, MS E518, Los Alamos, NM 87545 USA. EM figg@lanl.gov NR 11 TC 41 Z9 45 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 287 EP 291 DI 10.1016/S0169-4332(97)00644-2 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100045 ER PT J AU Borisov, OV Mao, XL Ciocan, AC Russo, RE AF Borisov, OV Mao, XL Ciocan, AC Russo, RE TI Time-resolved parametric studies of laser ablation using inductively coupled plasma atomic emission spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE ablated mass; laser fluences; zinc-to-copper ratio; laser parameters; spectral emission lines; initial signal spike ID MASS SPECTROMETRY; FRACTIONATION AB The quantity of ablated mass and its composition strongly depend on the number of laser pulses and laser fluence at the sample target surface. For chemical analysis, thin-film deposition,cutting, and other laser-ablation applications, the quantity of mass removed vs. number of laser pulses is important. In addition, the composition of the vapor can be critical, for example, in providing accurate chemical analysis or well-defined thin film structures. In this work, mass ablation rate and ablated mass composition were studied by monitoring the time dependence of emission intensity using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP) during repetitive laser ablation at a single location on the sample target. Spectral emission intensity in the ICP is directly related to the quantity of mass ablated by the laser. The ratio of spectral emission lines in the ICP gives an indication of the relative composition of ablated constituents. In this work, a brass sample was ablated using several lasers with various properties. Emission intensities of Cu and Zn ionic lines, after the occurrence of an initial signal spike, increase with increasing number of laser pulses at high fluence, whereas at low fluence no significant changes were observed in the mass ablation rate. The zinc-to-copper ratio was used to monitor fractionation processes during repetitive laser ablation. The ratio increased with increasing ablation time at low fluence. In contrast, the ratio was almost constant, and close to the accurate level at high laser fluences. The effect of various laser parameters on the mass ablation rate and mass composition are discussed in this paper. Published by Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 12 TC 10 Z9 10 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 315 EP 320 DI 10.1016/S0169-4332(97)00649-1 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100050 ER PT J AU Bililign, S Feigerle, CS Miller, JC AF Bililign, S Feigerle, CS Miller, JC TI Inverse laser ablation, formation and chemistry of nanoparticles from gaseous precursors SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE clusters; metal clusters; Nanoparticles; nanochemistry ID MULTIPHOTON IONIZATION; CLUSTER IONS; VANDERWAALS HETEROCLUSTERS; CARBON-DISULFIDE; DYNAMICS AB Unlike traditional laser ablation experiments where solids are volatilized by the focused laser beam, we give the term inverse laser ablation' to the process of particle formation following the interaction of the laser with a gaseous precursor. Experiments are described where the transition from a normally gas phase species to a normally condensed phase particle takes place within a single gas-phase cluster in a collisionless environment. In addition, by adding reactant molecules to the initial cluster, it is possible to observe and characterize chemical reactions occurring within this novel 'test tube'. In this technique, a heterocluster composed of iron pentacarbonyl molecules and potential reactant species is formed by coexpansion in a supersonic jet. Photoionization of the precursor molecules by a picosecond, 266 nm laser pulse efficiently strips away the ligands, leaving metal ions and metal cluster ions land neutrals) in close proximity to reactant molecules, Subsequent reactions take place which are followed by monitoring the products by time-of-flight mass spectrometry. The reaction with carbon disulfide is described in detail. (C) 1998 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Chem & Biol Phys Sect, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. N Carolina Agr & Technol State Univ, Dept Phys, Greensboro, NC 27411 USA. RP Miller, JC (reprint author), Oak Ridge Natl Lab, Chem & Biol Phys Sect, POB 20008, Oak Ridge, TN 37831 USA. EM bililign@ncat.edu; cfeigerle@utk.edu; millerjc@ornl.gov NR 23 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 344 EP 349 DI 10.1016/S0169-4332(97)00653-3 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100054 ER PT J AU Lowndes, DH Rouleau, CM Thundat, T Duscher, G Kenik, EA Pennycook, SJ AF Lowndes, DH Rouleau, CM Thundat, T Duscher, G Kenik, EA Pennycook, SJ TI Silicon and zinc telluride nanoparticles synthesized by pulsed laser ablation: size distributions and nanoscale structure SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE pulsed laser ablation; pulsed laser deposition; Si; ZnTe; nanoparticle; nanocrystal; size distribution; atomic force microscopy; scanning electron microscopy; transmission electron microscopy; Z-contrast ID THIN-FILM; INERT-GAS; GROWTH; DEPOSITION; PARTICLES; PRESSURE AB Size distributions of Si and ZnTe nanoparticles produced by low energy density ArF (193 nm) pulsed laser ablation into ambient gases were measured as a function of the gas pressure and target-substrate separation, D(ts), using atomic force microscopy (AFM) and high resolution scanning electron microscopy (HRSEM). For low energy density (E(d) = 1.04 J/cm(2)) ablation of Si into He at pressures of 0.5, 1.5, 4 and 10 Torr, large nanoparticles were most numerous at D(ts) = 10 mm, with smaller nanoparticles found at 20 mm and 40 mm. For each D(ts) value a maximum of the mean nanoparticle diameter occurred for a He pressure near 6 Torr, in contrast to other recent measurements in which the size of Si nanoparticles increased monotonically with the He pressure. High resolution Z-contrast transmission electron microscopy (HRZTEM) and electron energy loss spectroscopy (EELS) revealed that ZnTe nanoparticles formed by ablation into nitrogen at E(d) = 0.74 J/cm(2) consisted of a crystalline ZnTe core surrounded by an amorphous ZnO shell. Growth defects and surface steps were clearly visible in the ZnTe crystalline core. The dependencies of the mean diameter of ZnTe nanocrystals on nitrogen pressure and D(ts) were qualitatively similar to those found for Si in He. (C) 1998 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Lowndes, DH (reprint author), Oak Ridge Natl Lab, Div Solid State, Bldg 3150,POB 2008, Oak Ridge, TN 37831 USA. EM vdh@ornl.gov RI Duscher, Gerd/G-1730-2014; Rouleau, Christopher/Q-2737-2015 OI Duscher, Gerd/0000-0002-2039-548X; Rouleau, Christopher/0000-0002-5488-3537 NR 16 TC 56 Z9 60 U1 3 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 355 EP 361 DI 10.1016/S0169-4332(97)00655-7 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100056 ER PT J AU Rouleau, CM Lowndes, DH AF Rouleau, CM Lowndes, DH TI Growth of p-type ZnTe and n-type CdSe films on GaAs(001) by pulsed laser ablation SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE pulsed laser ablation; ArF (193 nm); doping ZnTe; cubic CdSe; indium-doped CdSe; nitrogen-doped ZnTe; stoichiometry; interface diffusion; ammonia ID MOLECULAR-BEAM EPITAXY; THIN-FILMS; DEPOSITION; SEMICONDUCTORS; NITROGEN; GAAS AB Thin films of p-type ZnTe and n-type CdSe were deposited on (001) and 2 degrees-miscut GaAs wafers by ArF (193 nm) pulsed laser ablation of stoichiometric ZnTe and CdSe targets through several ambient gas compositions and total pressures. Films were grown both with the substrate facing the plume (phi = 0 degrees) and with the substrate rotated by an angle, phi > 0 degrees. Substrates were affixed to the heater using conventional indium bonding and an indium-free method, Hall effect measurements were performed to determine the influence of target-to-substrate separation (D(TS)), substrate temperature, gas composition and total pressure, substrate orientation (phi), bonding method, and substrate miscut on the carrier concentration and mobility. NH(3) was found to be largely ineffective for p-type doping of ZnTe under the conditions explored and especially when compared to the wide range of resistivities achievable by employing nitrogen. In one instance, however, a Free-hole concentration of 2 x 10(18) cm(-3) (mu approximate to 3 cm(2)/V.s) was achieved by depositing at a large distance (D(TS) = 17.5 cm) and low temperature (200 degrees C) in 20 mTorr of NH(3). The Hall effect data for CdSe were found to cluster into two distinct regimes, one with mobilities less than or equal to 0.3 cm(2)/V.s and carrier concentrations greater than or equal to 3 x 10(20) cm(-3), the other with mobilities greater than or equal to 30 cm(2)/V.s and carrier concentrations less than or equal to 4 x 10(18) cm(-3). Examination of X-ray diffraction data coupled with reflection high-energy electron diffraction (RHEED) measurements, observations of the films' surfaces, and secondary ion mass spectroscopy (SIMS) profiling, indicated that no single-growth parameter was responsible for the observed bimodal behavior. (C) 1998 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Rouleau, CM (reprint author), Oak Ridge Natl Lab, Div Solid State, Bldg 3150,POB 2008, Oak Ridge, TN 37831 USA. EM xuc@ornl.gov RI Schaff, William/B-5839-2009; Rouleau, Christopher/Q-2737-2015 OI Rouleau, Christopher/0000-0002-5488-3537 NR 18 TC 34 Z9 34 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 418 EP 424 DI 10.1016/S0169-4332(97)00666-1 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100067 ER PT J AU Sudhir, GS Fujii, H Wong, WS Kisielowski, C Newman, N Dieker, C Liliental-Weber, Z Rubin, MD Weber, ER AF Sudhir, GS Fujii, H Wong, WS Kisielowski, C Newman, N Dieker, C Liliental-Weber, Z Rubin, MD Weber, ER TI Pulsed laser deposition of aluminum nitride and gallium nitride thin SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; GaN; AlN; buffer layer; structure; morphology ID BUFFER LAYER; EPITAXIAL-GROWTH; GAN; SAPPHIRE; FILMS AB Thin films of AlN and GaN were grown by pulsed laser deposition on c-plane sapphire substrates. It is demonstrated that the surface morphology and the structure of layers can actively be controlled by adjusting the nitrogen partial pressure during the growth. The observed trends in the structural quality of the thin films can be attributed to the changes in the surface diffusion of ad-atoms. The surface diffusion of ad-atoms can be influenced by the collisions between the nitrogen gas molecules and the activated atoms, which can reduce the kinetic energy of activated atoms and increase the rate of formation of immobile surface dimers. Through these nitrogen pressure-related effects, thin films with microstructure ranging from crystalline to amorphous can be produced. Our results on the growth of GaN and AlN thin films indicate that this pressure-assisted growth procedure is generally applicable to design the surface morphology of III-nitride thin films. A minimal surface root means square roughness of 0.7 nm for amorphous AlN is obtained, which compares well with the substrate roughness of 0.5 nm. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Northwestern Univ, Dept Elect & Comp Engn, Evanston, IL USA. RP Sudhir, GS (reprint author), Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, 438 Evans Hall, Berkeley, CA 94720 USA. EM gss@socrates.berkeley.edu RI Newman, Nathan/E-1466-2011; Liliental-Weber, Zuzanna/H-8006-2012 OI Newman, Nathan/0000-0003-2819-9616; NR 13 TC 25 Z9 26 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 471 EP 476 DI 10.1016/S0169-4332(97)00675-2 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100076 ER PT J AU Karnakis, DM Lippert, T Ichinose, N Kawanishi, S Fukumura, H AF Karnakis, DM Lippert, T Ichinose, N Kawanishi, S Fukumura, H TI Laser induced molecular transfer using ablation of a triazeno-polymer SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE fluorescence; triazene; pyrene; laser implantation; laser ablation transfer AB We report on the laser induced transfer of molecular dopants between thin polymer films. Pulsed UV laser radiation (355 nm) of moderate intensity, is directed through a transparent polymer film and absorbed by a photolabile triazeno-polymer (TP) doped with pyrene at low concentration. The explosive photodecomposition of TP results in the transfer of intact pyrene molecules to a tightly contacted neat polymer film of either poly(ethyl methacrylate) (PEMA) or poly(butyl methacrylate) (PBMA). Fluorometry of the receiving polymer surface indicated that the pyrene emission intensity grows as the laser pulse number increases but reduces with rising laser fluence. Surface examination suggests that most of the transferred dopant is implanted beneath the receiving polymer surface and the efficiency of this process is enhanced with lowering of its glass transition temperature T(g). A mechanism is discussed to explain the current experimental results. (C) 1998 Elsevier Science B.V. C1 Japan Atom Energy Res Inst, Adv Sci Res Ctr, Neyagawa, Osaka 572, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Osaka Univ, Dept Appl Phys, Suita, Osaka 565, Japan. RP Karnakis, DM (reprint author), Japan Atom Energy Res Inst, Adv Sci Res Ctr, 25-1 Mii Minami, Neyagawa, Osaka 572, Japan. EM karnakis@apr.jaeri.go.jp RI Fukumura, Hiroshi/G-4535-2011; Lippert, Thomas/N-2423-2016 NR 11 TC 29 Z9 29 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 781 EP 786 DI 10.1016/S0169-4332(97)00742-3 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100130 ER PT J AU Webb, RL Langford, SC Dickinson, JT Lippert, TK AF Webb, RL Langford, SC Dickinson, JT Lippert, TK TI Sensitization of PMMA to laser ablation at 308 nm SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE PMMA; laser ablation; photo-resist ID DOPANT-INDUCED ABLATION; POLY(METHYL METHACRYLATE); EXCIMER-LASER; ROTATIONAL RELAXATION; POLYMERS; POLYMETHYLMETHACRYLATE; PHOTOABLATION; CHLOROBENZENE; IRRADIATION; TEMPERATURE AB Pure polymethylmethacrylate (PMMA) is highly resistant to ablation at 308 nm. The value of PMMA in lithography and semiconductor packaging and the availability of reliable 308 nm optics has motivated the development of dopants to facilitate PMMA ablation at 308 nm. We investigate the laser ablation of solvent cast PMMA films with and without pyrene, a typical dopant. The presence of residual solvent is shown to strongly promote laser ablation at low fluences in the case of chlorobenzene (CB), but not in the case of N-methyl 2-pyrrolidinone (NMP). At low laser fluences, many laser pulses may be required before significant neutral particle emissions are observed - an incubation effect. Scanning electron microscope observations indicate that the onset of emission coincides with the rupture of a thin surface layer, presumably depleted of solvent during film manufacture. The depleted layer would be relatively impervious to volatile fragments produced in the bulk. When this layer ruptures, volatile fragments escape and can be detected. Thus, the ablation behavior depends not only on the choice of dopant, but on the choice of solvent and the details of film manufacture. (C) 1998 Elsevier Science B.V. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Dickinson, JT (reprint author), Washington State Univ, Dept Phys, Pullman, WA 99164 USA. EM jtd@wsu.edu.us RI Lippert, Thomas/N-2423-2016 NR 29 TC 15 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 815 EP 820 DI 10.1016/S0169-4332(97)00748-4 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100136 ER PT J AU Kim, BM Feit, MD Rubenchik, AM Mammini, BM Da Silva, LB AF Kim, BM Feit, MD Rubenchik, AM Mammini, BM Da Silva, LB TI Optical feedback signal for ultrashort laser-pulse ablation of tissue SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE ultrashort pulse laser; tissue ablation; plasma luminescence; tissue fluorescence; optical feedback system ID CORNEAL TISSUE; SHOCK-WAVES; AUTOFLUORESCENCE; SPECTROSCOPY; DYNAMICS; SYSTEM; PLAQUE; WATER AB An optical feedback system for controlled precise tissue ablation is discussed. Our setup includes an ultrashort pulse laser (USPL), and a diagnostic system utilizing analysis of either tissue fluorescence or plasma emission luminescence. Current research is focused on discriminating hard and soft tissues such as bone and spinal cord during spinal surgery using either technique. Our experimental observations exhibit considerable spectroscopic contrast between hard and soft tissue, and both techniques offer promise for a practical diagnostic system. (C) 1998 Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kim, BM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,Mail Stop L-399, Livermore, CA 94550 USA. EM kim12@llnl.gov RI Feit, Michael/A-4480-2009 NR 19 TC 37 Z9 37 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 857 EP 862 DI 10.1016/S0169-4332(97)00756-3 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100144 ER PT J AU Feit, MD Rubenchik, AM Kim, BM da Silva, LB Perry, MD AF Feit, MD Rubenchik, AM Kim, BM da Silva, LB Perry, MD TI Physical characterization of ultrashort laser pulse drilling of biological tissue SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE ultrashort laser pulse ablation; biological tissue; physical characterization ID DIELECTRICS; NANOSECOND; ABLATION AB Ultrashort laser pulse ablation removes material with low-energy fluence required and minimal collateral damage. The ultimate usefulness of this technology for biomedical application depends, in part, on characterization of the physical conditions attained, and determination of the zone of shockwave and heat-affected material in particular tissues. Detailed numerical modeling of the relevant physics (deposition, plasma formation, shockwave generation and propagation, thermal conduction) are providing this information. A wide range of time scales is involved, ranging from picosecond for energy deposition and peak pressure and temperature, to nanosecond for development of shockwave, to microsecond for macroscopic thermophysical response. (C) 1998 Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Feit, MD (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,Mail Stop L-439, Livermore, CA 94550 USA. EM feit1@llnl.gov; rubenchik1@llnl.gov; kim12@llnl.gov; dasilva1@llnl.gov; perry10@llnl.gov RI Feit, Michael/A-4480-2009 NR 16 TC 37 Z9 37 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 869 EP 874 DI 10.1016/S0169-4332(97)00758-7 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100146 ER PT J AU Bushaw, BA Alexander, ML AF Bushaw, BA Alexander, ML TI Investigation of laser ablation plume dynamics by high-resolution time-resolved atomic absorption spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; absorption; dynamics; strontium AB The dynamics of neutral and singly ionized strontium, produced as minor components in the laser ablation of amorphous calcium carbonate (chalk), have been investigated by space- and time-resolved atomic absorption spectroscopy. Absorption of a probe beam from a single-frequency cw dye laser was used to monitor the subject species at 420.7 nm (ion) and 460.7 nm (neutral). Results including time-resolved absorption profiles, energy distributions and the effect of a cover gas are presented and discussed. (C) 1998 Elsevier Science B.V. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Bushaw, BA (reprint author), Pacific NW Lab, POB 999,MS K3-58, Richland, WA 99352 USA. EM ba_bushaw@pnl.gov NR 11 TC 10 Z9 10 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 935 EP 940 DI 10.1016/S0169-4332(97)00769-1 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100157 ER PT J AU Jeong, SH Greif, R Russo, RE AF Jeong, SH Greif, R Russo, RE TI Propagation of the shock wave generated from excimer laser heating of aluminum targets in comparison with ideal blast wave theory SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE laser ablation; blast wave; probe beam deflection ID ABLATION; SURFACE AB Propagation of the shock wave generated during pulsed laser heating of aluminum targets was measured utilizing a probe beam deflection technique. The transit time of the laser-generated shock wave was compared with that predicted from the Sedov-Taylor solution for an ideal spherical blast wave. It was found that the most important parameters for the laser-generated shock wave to be consistent with the theoretically predicted propagation are the ambient pressure and the laser beam spot size. The prediction for laser energy conversion into the laser-induced vapor flow using the Sedov-Taylor solution overestimated the energy coupling efficiency, indicating a difference between a laser-induced gas-dynamic flow and an ideal blast wave. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Engn Mech, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM rerusso@lbl.gov NR 13 TC 48 Z9 50 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 1029 EP 1034 DI 10.1016/S0169-4332(97)00785-X PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100174 ER PT J AU Burger, J Gibbons, JW AF Burger, J Gibbons, JW TI Trace elements in egg contents and egg shells of slider turtles (Trachemys scripta) from the savannah river site SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID CHELYDRA-SERPENTINA SERPENTINA; LAKE-ONTARIO; HEAVY-METALS; CANADA; CONTAMINANTS; MERCURY; POPULATION AB In this paper we examine the levels of trace elements in the egg contents and egg shells of slider turtles (Trachemys scripta) from the Savannah River Site, near Aiken, South Carolina. Trace elements have seldom been examined in the tissues or eggs of reptiles, although some turtles and large snakes occupy a high trophic level. Lead, mercury, cadmium, selenium, chromium, and manganese levels were examined in one egg and its egg shell collected from each of 16 females that laid in late May and June 1995. We were interested in determining background levels, whether certain metals were sequestered in the egg shells, and whether levels were higher in contents or shells. Concentrations were higher in egg contents than in shells for lead, mercury, and selenium, while chromium was higher in the shell. There were no differences for cadmium and manganese. Compared to eggs from other reptiles, levels in slider turtles were generally similar for cadmium and selenium, lower for chromium and lead, and higher for manganese. C1 Rutgers State Univ, Nelson Biol Lab, Grad Program Ecol & Evolut, Piscataway, NJ 08854 USA. Environm & Occupat Hlth Sci Inst, Piscataway, NJ 08855 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Burger, J (reprint author), Rutgers State Univ, Nelson Biol Lab, Grad Program Ecol & Evolut, Piscataway, NJ 08854 USA. FU NIEHS NIH HHS [ESO 5022] NR 35 TC 31 Z9 31 U1 1 U2 12 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD MAY PY 1998 VL 34 IS 4 BP 382 EP 386 PG 5 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZE977 UT WOS:000072850500011 PM 9543509 ER PT J AU Gariboldi, JC Jagoe, CH Bryan, AL AF Gariboldi, JC Jagoe, CH Bryan, AL TI Dietary exposure to mercury in nestling wood storks (Mycteria americana) in Georgia SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID METHYLMERCURY; EVERGLADES; HERONS; FISH AB The United States breeding population of the wood stork (Mycteria americana) was listed as endangered in 1984; the U.S. Fish and Wildlife Service has listed the determination of potential contaminant hazards as a task important to the recovery of the species. Storks nest in colonies and adult storks forage over wide areas and return with prey items to feed to nestlings. The most recently consumed prey items are usually regurgitated by nestlings when they are handled. In 1995, over 200 food items from four wood stork colonies were collected while banding nestlings between 20 and 40 days old, and total mercury determined in individual food items. Two colonies were located on the Atlantic coast and two in inland areas. Overall dietary mercury concentration for each colony was calculated based on the biomass of each type of food item within the diet. Freshwater prey items had higher mercury concentrations than saltwater items most frequently chosen by storks. Daily Hg doses were estimated for a range of nestling sizes and daily food consumption rates. Risk factors were calculated based on two lowest observable adverse effect concentrations (LOAECs) from previous avian mercury ingestion studies. Based on one LOAEC, all four colonies in this study were at risk of sublethal effects due to mercury in the diet of nestling wood storks. More extensive studies of sublethal effects in avian species from mercury contamination are necessary for more accurate risk assessment. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Gariboldi, JC (reprint author), Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. NR 29 TC 22 Z9 22 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD MAY PY 1998 VL 34 IS 4 BP 398 EP 405 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZE977 UT WOS:000072850500013 ER PT J AU Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, A Bennett, DP Cook, KH Freeman, KC Griest, K Lawson, WA Lehner, MJ Marshall, SL Minniti, D Peterson, BA Pollard, KR Pratt, MR Quinn, PJ Rodgers, AW Sutherland, W Tomaney, A Welch, DL AF Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, A Bennett, DP Cook, KH Freeman, KC Griest, K Lawson, WA Lehner, MJ Marshall, SL Minniti, D Peterson, BA Pollard, KR Pratt, MR Quinn, PJ Rodgers, AW Sutherland, W Tomaney, A Welch, DL TI The MACHO project LMC variable star inventory. VII. The discovery of RV Tauri stars and new type II Cepheids in the large magellanic cloud SO ASTRONOMICAL JOURNAL LA English DT Article DE Magellanic Clouds; stars, Population II; stars, variables, other ID PULSATING VARIABLES; LUMINOSITY; METALLICITY; OVERTONE; VIRGINIS; PERIODS; MODELS AB We report the discovery of RV Tauri stars in the Large Magellanic Cloud (LMC). In light-and color-curve behavior, the RV Tauri stars appear to be a direct extension of the type II Cepheids to longer periods. A single period-luminosity-color relationship is seen to describe both the type II Cepheids and the RV Tauri stars in the LMC. We derive the relation V-0 = 17.89(+/- 0.20)-2.95(+/- 0.12) log P + 5.49(+/-0.35)[(V-R)(0)], which is valid for type II Cepheids and RV Tauri stars in the period range 0.9 < log P < 1.75. Assuming a distance modulus to the LMC of 18.5, the relation in terms of the absolute luminosities becomes M-V = -0.61(+/-0.20)-2.95(+/-0.12) log P + 5.49(+/-0.35)[(V-R)(0)]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, Supercomp Facil, Canberra, ACT 0200, Australia. Univ Calif Davis, Dept Phys, Livermore, CA 95616 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Univ Washington, Dept Phys & Astron, Seattle, WA 98195 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ New S Wales, Australian Def Force Acad, Dept Phys, Canberra, ACT 2600, Australia. S African Astron Observ, ZA-7935 Observatory, South Africa. Univ Canterbury, Dept Phys & Astron, Christchurch 1, New Zealand. European So Observ, D-85748 Garching, Germany. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RP Alcock, C (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Quinn, Peter/B-3638-2013; Stubbs, Christopher/C-2829-2012; OI Stubbs, Christopher/0000-0003-0347-1724; Lehner, Matthew/0000-0003-4077-0985 NR 40 TC 72 Z9 72 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1998 VL 115 IS 5 BP 1921 EP 1933 DI 10.1086/300317 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100016 ER PT J AU Ramsdell, JV Fosmire, CJ AF Ramsdell, JV Fosmire, CJ TI Estimating concentrations in plumes released in the vicinity of buildings: Model development SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE atmospheric dispersion; dispersion parameters; building wakes; atmospheric turbulence; experimental data ID GROUND-LEVEL RELEASES; DIFFUSION; DISPERSION; SCHEMES; WAKES AB A model is developed for near-field diffusion of effluents released on and near buildings. The model consists of low-and high-speed diffusion increments to the dispersion parameters in a Gaussian plume model. Building wake turbulence and diffusion data are used to evaluate model parameters. These data indicate that the low wind speed diffusion increment is both appropriate and necessary. They also indicate that the high-speed increment is appropriate, but that it is unnecessary. A companion paper compares model concentration predictions with measured concentrations, with concentrations predicted by standard wake models, and with concentrations predicted by alternative, non-Gaussian models designed to estimate bounding concentrations in building wakes. The model is shown to be conservative and predict concentrations in the vicinity of buildings better than other models. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Ramsdell, JV (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. EM j.ramsdell@pnl.gov NR 28 TC 4 Z9 5 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAY PY 1998 VL 32 IS 10 BP 1663 EP 1677 DI 10.1016/S1352-2310(97)00450-0 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZP051 UT WOS:000073711600003 ER PT J AU Ramsdell, JV Fosmire, CJ AF Ramsdell, JV Fosmire, CJ TI Estimating concentrations in plumes released in the vicinity of buildings: Model evaluation SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE atmospheric dispersion; dispersion parameters; building wakes; atmospheric turbulence; experimental data ID GROUND-LEVEL RELEASES; DISPERSION; DIFFUSION; WAKES AB A model was developed in a companion paper for estimating the concentrations of effluents released on and near buildings. This paper compares model concentration predictions with measured concentrations, with concentrations predicted by standard wake models and with concentrations predicted by alternative, non-Gaussian models designed to estimate bounding concentrations in building wakes. The model is shown to be conservative and to predict concentrations in the vicinity of buildings better than other models. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Ramsdell, JV (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. EM j.ramsdell@pnl.gov NR 23 TC 3 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAY PY 1998 VL 32 IS 10 BP 1679 EP 1689 DI 10.1016/S1352-2310(97)00451-2 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZP051 UT WOS:000073711600004 ER PT J AU Schmeichel, KL Beckerle, MC AF Schmeichel, KL Beckerle, MC TI LIM domains of cysteine-rich protein 1 (CRP1) are essential for its zyxin-binding function SO BIOCHEMICAL JOURNAL LA English DT Article ID MOLECULAR CHARACTERIZATION; ZINC; HOMEODOMAIN; ASSOCIATION; MOTIF; RBTN2; DIFFERENTIATION; TRANSCRIPTION; CYTOSKELETON; REQUIREMENT AB Previous studies have demonstrated that the adhesion-plaque protein, zyxin, interacts specifically with a 23 kDa protein, called the cysteine-rich protein 1 (CRP1), which has been implicated in myogenesis. Primary sequence analyses have revealed that both zyxin and CRP1 exhibit multiple copies of a structural motif called the LIM domain. LIM domains, which are defined by the consensus CX2CX16-23HX2CX2CX2CX16-23CX2-3(C,H,D), are found in a variety of proteins that are involved in cell growth and differentiation. Recent studies have established that LIM domains are zinc-binding structures that mediate specific protein-protein interactions. For example, in the case of the zyxin-CRP1 interaction, one of zyxin's three LIM domains is necessary and sufficient for binding to CRP1. Because the CRP1 molecule is comprised primarily of two LIM domains, we were interested in the possibility that the binding site for zyxin on CRP1 might also be contained within a single LIM domain. Consistent with the hypothesis that the LIM domains of CRP1 are critical for the protein's zyxin-binding function, zinc-depleted CRP1 displays a reduced zyxin-binding activity. However, domain mapping analyses have revealed that neither of the two individual LIM domains of CRP1 can support a wild-type interaction with zyxin. Collectively, our results suggest that the binding site for zyxin on CRP1 is not contained within a single contiguous sequence of amino acids, Instead, the interaction appears to rely on the co-ordinate action of a number of residues that are displayed in both of CRP1's LIM domains. C1 Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Beckerle, MC (reprint author), Univ Utah, Dept Biol, 204 So Biol, Salt Lake City, UT 84112 USA. EM beckerle@bioscience.utah.edu FU NCI NIH HHS [CA-09602]; NIGMS NIH HHS [GM-50877] NR 44 TC 24 Z9 27 U1 0 U2 1 PU PORTLAND PRESS PI LONDON PA 59 PORTLAND PLACE, LONDON, ENGLAND W1N 3AJ SN 0264-6021 J9 BIOCHEM J JI Biochem. J. PD MAY 1 PY 1998 VL 331 BP 885 EP 892 PN 3 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZN108 UT WOS:000073610700027 PM 9560318 ER PT J AU Getz, EB Cooke, R Selvin, PR AF Getz, EB Cooke, R Selvin, PR TI Luminescence resonance energy transfer measurements in myosin SO BIOPHYSICAL JOURNAL LA English DT Article ID DICTYOSTELIUM-DISCOIDEUM MYOSIN; X-RAY-SCATTERING; SKELETAL-MUSCLE; MOTOR DOMAIN; ORIENTATION FACTOR; HEAVY-MEROMYOSIN; ATPASE ACTIVITY; LIGHT-CHAINS; ADP RELEASE; NECK REGION AB Myosin is thought to generate force by a rotation between the relative orientations of two domains. Direct measurements of distances between the domains could potentially confirm and quantify these conformational changes, but efforts have been hampered by the large distances involved. Here we show that luminescence resonance energy transfer (LRET), which uses a luminescent lanthanide as the energy-transfer donor, is capable of measuring these long distances. Specifically, we measure distances between the catalytic domain (Cys(707)) and regulatory light chain domain (Cys(108)) of the myosin head. An energy transfer efficiency of 21.2 +/- 1.9% is measured in the myosin complex without nucleotide or actin, corresponding to a distance of 73 Angstrom, consistent with the crystal structure of Rayment et al. Upon binding to actin, the energy transfer efficiency decreases by 4.5 +/- 1.0%, indicating a conformational change in myosin that involves a relative rotation and/or translation of Cys(707) relative to the light chain domain. Addition of ADP also alters the energy transfer efficiency, likely through a rotation of the probe attached to Cys(707). These results demonstrate that LRET is capable of making accurate measurements on the relatively large actomyosin complex, and is capable of detecting conformational changes between the catalytic and light chain domains of myosin. C1 Univ Illinois, Loomis Lab Phys, Dept Phys, Urbana, IL 61801 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Cardiovasc Res Inst, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Biochem & Biophys, San Francisco, CA 94143 USA. RP Univ Illinois, Loomis Lab Phys, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. EM selvin@uiuc.edu NR 54 TC 30 Z9 30 U1 0 U2 4 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 EI 1542-0086 J9 BIOPHYS J JI Biophys. J. PD MAY PY 1998 VL 74 IS 5 BP 2451 EP 2458 PG 8 WC Biophysics SC Biophysics GA ZL406 UT WOS:000073429700032 ER PT J AU Laible, PD Chynwat, V Thurnauer, MC Schiffer, M Hanson, DK Frank, HA AF Laible, PD Chynwat, V Thurnauer, MC Schiffer, M Hanson, DK Frank, HA TI Protein modifications affecting triplet energy transfer in bacterial photosynthetic reaction centers SO BIOPHYSICAL JOURNAL LA English DT Article ID RHODOBACTER-SPHAEROIDES R-26; PRIMARY ELECTRON-DONOR; MODIFIED BACTERIOCHLOROPHYLL PIGMENTS; RHODOPSEUDOMONAS-VIRIDIS; SPIN RESONANCE; STATE; RESOLUTION; CAPSULATUS; SPHEROIDENE; CAROTENOIDS AB The efficiency of triplet energy transfer from the special pair (P) to the carotenoid (C) in photosynthetic reaction centers (RCs) from a large family of mutant strains has been investigated. The mutants carry substitutions at positions L181 and/or M208 near chlorophyll-based cofactors on the inactive and active sides of the complex, respectively. Light-modulated electron paramagnetic resonance at 10 K, where triplet energy transfer is thermally prohibited, reveals that the mutations do not perturb the electronic distribution of P. At temperatures greater than or equal to 70 K, we observe reduced signals from the carotenoid in most of the RCs with L181 substitutions. In particular, triplet transfer efficiency is reduced in all RCs in which a lysine at L181 donates a sixth ligand to the monomeric bacteriochlorophyll B-B. Replacement of the native Tyr at M208 on the active side of the complex with several polar residues increased transfer efficiency. The difference in the efficiencies of transfer in the RCs demonstrates the ability of the protein environment to influence the electronic overlap of the chromophores and thus the thermal barrier for triplet energy transfer. C1 Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. RP Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. EM laible@anl.gov FU NIGMS NIH HHS [5 RO1 GM36598, GM30353] NR 58 TC 16 Z9 16 U1 0 U2 5 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 EI 1542-0086 J9 BIOPHYS J JI Biophys. J. PD MAY PY 1998 VL 74 IS 5 BP 2623 EP 2637 PG 15 WC Biophysics SC Biophysics GA ZL406 UT WOS:000073429700047 PM 9591686 ER PT J AU Milanovich, N Reinot, T Hayes, JM Small, GJ AF Milanovich, N Reinot, T Hayes, JM Small, GJ TI Aluminum phthalocyanine tetrasulfonate in MCF-10F, human breast epithelial cells: A hole burning study SO BIOPHYSICAL JOURNAL LA English DT Article ID HYPERQUENCHED GLASSY FILMS; PRIMARY CHARGE SEPARATION; CULTURED MAMMALIAN-CELLS; POLYVINYL-ALCOHOL FILMS; CRESYL VIOLET; PHOTODYNAMIC SENSITIZERS; PHOTOCHEMICAL HOLES; RELAXATION DYNAMICS; DISPERSIVE KINETICS; AMORPHOUS SOLIDS AB Laser-induced holes are burned in the absorption spectrum of aluminum phthalocyanine tetrasulfonate (APT) in MCF-10F, human breast epithelial cells. The hole burning mechanism is shown to be nonphotochemical. The fluorescence excitation spectra and hole spectra are compared with those of APT in hyperquenched glassy films of water, ethanol, and methanol. The results show that the APT is in an acidic, aqueous environment with a hydrogen-bonded network similar to that of glassy water, but showing the influence of other cellular components. Pressure shifts of holes allow the local compressibility about the APT to be determined. C1 Iowa State Univ Sci & Technol, Ames Lab, USDOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Hayes, JM (reprint author), Iowa State Univ Sci & Technol, Ames Lab, USDOE, Ames, IA 50011 USA. EM jmhayes@iastate.edu NR 50 TC 6 Z9 6 U1 0 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAY PY 1998 VL 74 IS 5 BP 2680 EP 2688 PG 9 WC Biophysics SC Biophysics GA ZL406 UT WOS:000073429700053 PM 9591692 ER PT J AU Lee, JY Xun, LY AF Lee, JY Xun, LY TI Novel biological process for L-DOPA production from L-tyrosine by p-hydroxyphenylacetate 3-hydroxylase SO BIOTECHNOLOGY LETTERS LA English DT Article ID ESCHERICHIA-COLI AB A novel biological method was developed for the production of L-3,4-dihydroxyphenylalanine (L-DOPA) from L-tyrosine by p-hydroxyphenylacetate 3-hydroxylase of Escherichia coli strain W (ATCC 11105). About 48 mM (or 1% w/v) L-DOPA was obtained by a fed batch operation in 50 h when a recombinant strain constitutively producing the enzyme was used. C1 Pacific NW Lab, Environm Microbiol Grp, Richland, WA 99352 USA. RP Xun, LY (reprint author), Washington State Univ, Dept Microbiol, Pullman, WA 99164 USA. NR 8 TC 14 Z9 14 U1 1 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0141-5492 J9 BIOTECHNOL LETT JI Biotechnol. Lett. PD MAY PY 1998 VL 20 IS 5 BP 479 EP 482 DI 10.1023/A:1005440229420 PG 4 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 102HF UT WOS:000074917800009 ER PT J AU Panofsky, WKH AF Panofsky, WKH TI A viable option SO BULLETIN OF THE ATOMIC SCIENTISTS LA English DT Letter C1 Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. RP Panofsky, WKH (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EDUC FOUNDATION NUCLEAR SCI PI CHICAGO PA 6042 SOUTH KIMBARK, CHICAGO, IL 60637 USA SN 0096-3402 J9 B ATOM SCI JI Bull. Atom. Scient. PD MAY-JUN PY 1998 VL 54 IS 3 BP 3 EP 4 PG 2 WC International Relations; Social Issues SC International Relations; Social Issues GA ZJ733 UT WOS:000073247500003 ER PT J AU Sailor, WC AF Sailor, WC TI Don't reprocess SO BULLETIN OF THE ATOMIC SCIENTISTS LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Sailor, WC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EDUC FOUNDATION NUCLEAR SCI PI CHICAGO PA 6042 SOUTH KIMBARK, CHICAGO, IL 60637 USA SN 0096-3402 J9 B ATOM SCI JI Bull. Atom. Scient. PD MAY-JUN PY 1998 VL 54 IS 3 BP 4 EP 4 PG 1 WC International Relations; Social Issues SC International Relations; Social Issues GA ZJ733 UT WOS:000073247500004 ER PT J AU Hiraguri, S Godfrey, T Nakamura, H Graff, J Collins, C Shayesteh, L Doggett, N Johnson, K Wheelock, M Herman, J Baylin, S Pinkel, D Gray, J AF Hiraguri, S Godfrey, T Nakamura, H Graff, J Collins, C Shayesteh, L Doggett, N Johnson, K Wheelock, M Herman, J Baylin, S Pinkel, D Gray, J TI Mechanisms of inactivation of E-cadherin in breast cancer cell lines SO CANCER RESEARCH LA English DT Article ID FLUORESCENCE INSITU HYBRIDIZATION; MOLECULE E-CADHERIN; PROSTATE-CANCER; GENETIC ALTERATIONS; CARCINOMA-CELLS; EXPRESSION; ADHESION; MUTATIONS; METASTASES; ACID AB Loss of E-cadherin (CDH1) function is thought to contribute to progression in breast cancer and other solid tumors by increasing proliferation, invasion, and/or metastasis. In some cases, the restoration of CDH1 function may be an important therapeutic option. This possibility will depend on the mechanism by which CDH1 is inactivated. Here we present analyses of CDH1 expression, genetic mutation, and promoter methylation in CDH1 in 10 commonly used breast cancer cell lines. Five cell Lines (BT-474, MCF-7, MDA-MB-361, MDA-MB-468, and T-47D) expressed CDH1 and were genetically normal. Five others (SK-BR-3, 600 MPE, MDA-MB-134 IV, CAMA1, and MDA-MB-435) did not express CDH1, Fluorescence in situ hybridization analyses of each of these cell lines showed evidence for the physical deletion of one allele of CDH1, and three cell lines were found to carry homozygous deletions. SK-BR-3 was deleted from exon 12 through the promoter; exon 6 was deleted in MDA-MB-134 TV cells, and 600 MPE cells carried a 21-bp deletion in the splicing acceptor site for exon 9. CAMA1 seemed to have been inactivated through promoter methylation No explanation was found for the inactivation of CDH1 in MDA-MB-435. C1 Univ Calif San Francisco, Ctr Canc, Canc Genet Program, San Francisco, CA 94143 USA. Johns Hopkins Univ, Ctr Oncol, Baltimore, MD 21205 USA. Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Toledo, Toledo, OH 43606 USA. RP Gray, J (reprint author), Univ Calif San Francisco, Ctr Canc, Canc Genet Program, San Francisco, CA 94143 USA. RI Godfrey, Tony/A-5572-2013 OI Godfrey, Tony/0000-0002-3283-6983 FU NCI NIH HHS [CA58207] NR 39 TC 109 Z9 115 U1 1 U2 4 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD MAY 1 PY 1998 VL 58 IS 9 BP 1972 EP 1977 PG 6 WC Oncology SC Oncology GA ZK631 UT WOS:000073344700033 PM 9581841 ER PT J AU Mauthe, RJ Snyderwine, EG Ghoshal, A Freeman, SPHT Turteltaub, KW AF Mauthe, RJ Snyderwine, EG Ghoshal, A Freeman, SPHT Turteltaub, KW TI Distribution and metabolism of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in female rats and their pups at dietary doses SO CARCINOGENESIS LA English DT Article ID ACCELERATOR MASS-SPECTROMETRY; FOOD-DERIVED CARCINOGEN; HETEROCYCLIC AMINES; COOKED BEEF; MUTAGEN PHIP; BREAST-MILK; CHLOROPHYLLIN; EXPOSURE; INHIBITION; PRODUCTS AB 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a mammary carcinogen in female rats and is present in a wide variety of cooked meats. We address here the excretion of PhIP and its metabolites into the breast-milk of lactating rats and the ability of chlorophyllin, a food product derivative with chemopreventive properties, to affect these levels at low PhIP doses. Lactating female F344 rats with suckling pups were orally administered 50, 500 and 1000 ng [C-14]PhIP/kg body weight. The excretion of the [C-14]PhIP into milk and its distribution among the mammary tissue, liver and blood of the dam, as well as among stomach contents and liver of their suckling pups was measured using accelerator mass spectrometry (AMS), PhIP, PhIP-4'-sulfate, 4'-hydroxy-PhIP, and N-2-hydroxy-PhIP-N-3-glucuronide were found in the milk at all doses. The chlorophyllin (500 mu g/kg) co-administration with PhIP (500 ng/kg) caused increased levels of [C-14]PhIP in the milk (32%) and stomach contents (35%) of the pups relative to the animals not receiving chlorophyllin at these low PhIP doses. In contrast, lower [C-14]PhIP levels in the chlorophyllin treated animals were observed in the blood (47%) and mammary tissue (68%) of the dam, as well as the pup's liver tissue (37%) compared to the animals receiving only PhIP, Chlorophyllin co-administration resulted in an increased amount of N-2-hydroxy-PhIP-N-3-glucuronide (42%), increased PhIP (79%) and decreased levels of PhIP-4'-sulphate (77%) relative to the animals not receiving chlorophyllin. These results suggest that PhIP and PhIP metabolites are present in the breast-milk of lactating rats at human dietary PhIP exposures and that PhIP is absorbed by the newborn. Furthermore, these results suggest that other dietary components can affect the dosimetry of PhIP in breast-feeding offspring. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. NCI, Expt Carcinogenesis Lab, Bethesda, MD 20892 USA. RP Turteltaub, KW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Livermore, CA 94551 USA. RI Freeman, Stewart/C-3290-2012 OI Freeman, Stewart/0000-0001-6148-3171 FU NCI NIH HHS [CA55861] NR 47 TC 23 Z9 23 U1 0 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 1998 VL 19 IS 5 BP 919 EP 924 DI 10.1093/carcin/19.5.919 PG 6 WC Oncology SC Oncology GA ZP686 UT WOS:000073778300029 PM 9635883 ER PT J AU Carney, JP Maser, RS Olivares, H Davis, EM Le Beau, M Yates, JR Hays, L Morgan, WF Petrini, JHJ AF Carney, JP Maser, RS Olivares, H Davis, EM Le Beau, M Yates, JR Hays, L Morgan, WF Petrini, JHJ TI The hMre11/hRad50 protein complex and Nijmegen breakage syndrome: Linkage of double-strand break repair to the cellular DNA damage response SO CELL LA English DT Article ID ATAXIA-TELANGIECTASIA; SACCHAROMYCES-CEREVISIAE; ESCHERICHIA-COLI; BLOOMS SYNDROME; MEIOTIC RECOMBINATION; GENETIC-RECOMBINATION; HUMAN MRE11; IDENTIFICATION; RAD50; FIBROBLASTS AB Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder characterized by increased cancer incidence, cell cycle checkpoint defects, and ionizing radiation sensitivity. We have isolated the gene encoding p95, a member of the hMre11/hRad50 double-strand break repair complex. The p95 gene mapped to 8q21.3, the region that contains the NBS locus, and p95 was absent from NBS cells established from NBS patients, p95 deficiency in these cells completely abrogates the formation of hMre11/hRad50 ionizing radiation-induced foci. Comparison of the p95 cDNA to the NBS1 cDNA indicated that the p95 gene and NBS1 are identical. The implication of hMre11/hRad50/p95 protein complex in NBS reveals a direct molecular link between DSB repair and cell cycle checkpoint functions. C1 Univ Wisconsin, Sch Med, Genet Lab, Madison, WI 53706 USA. Univ Calif San Francisco, Dept Radiat Oncol, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Washington, Dept Mol Biotechnol, Seattle, WA 98195 USA. Univ Chicago, Dept Med, Hematol Oncol Sect, Chicago, IL 60637 USA. RP Petrini, JHJ (reprint author), Univ Wisconsin, Sch Med, Genet Lab, Madison, WI 53706 USA. RI Maser, Richard/B-2970-2012 FU NCRR NIH HHS [5P41RR11823-02]; NIGMS NIH HHS [GM 52095, GM56888] NR 67 TC 840 Z9 856 U1 2 U2 27 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 0092-8674 J9 CELL JI Cell PD MAY 1 PY 1998 VL 93 IS 3 BP 477 EP 486 DI 10.1016/S0092-8674(00)81175-7 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA ZL787 UT WOS:000073471500022 PM 9590181 ER PT J AU Kohara, S Goldbach, A Koura, N Saboungi, ML Curtiss, LA AF Kohara, S Goldbach, A Koura, N Saboungi, ML Curtiss, LA TI Vibrational frequencies of small selenium molecules SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ABSORPTION-SPECTRA; CLUSTERS; RAMAN; TRIMERS; SE-3; MORDENITE; ZEOLITES; SULFUR; DIMERS AB The geometries and vibrational frequencies of Se(n) clusters (n = 2-8) are calculated using abinitio molecular orbital theory at various levels of approximation. The computed vibrational frequencies are in satisfactory agreement with the available experimental data on matrix isolated clusters and have small systematic deviations with IR and Raman spectra of crystalline Sr(6) (D(3d)) and Se(8) (D(4d)). The calculations provide predictions for future experimental studies. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Kohara, S (reprint author), Tokyo Univ Sci, Dept Ind Chem, Tokyo 162, Japan. RI Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 35 TC 45 Z9 45 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 1 PY 1998 VL 287 IS 3-4 BP 282 EP 288 DI 10.1016/S0009-2614(98)00184-5 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZL106 UT WOS:000073399400011 ER PT J AU Patel, DJ Mao, B Gu, ZT Hingerty, BE Gorin, A Basu, AK Broyde, S AF Patel, DJ Mao, B Gu, ZT Hingerty, BE Gorin, A Basu, AK Broyde, S TI Nuclear magnetic resonance solution structures of covalent aromatic amine-DNA adducts and their mutagenic relevance SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Review ID 2 INTERCHANGEABLE CONFORMATIONS; ATTACHED AMINOFLUORENE RING; C-8-MODIFIED SYN GUANINE; ESCHERICHIA-COLI; FRAMESHIFT MUTAGENESIS; CARCINOGEN N-2-ACETYLAMINOFLUORENE; ENERGY MINIMIZATION; RAS PROTOONCOGENE; COMPUTATIONAL CHARACTERIZATION; 2-AMINOFLUORENE-MODIFIED DNA C1 Mem Sloan Kettering Canc Ctr, Cellular Biochem & Biophys Program, New York, NY 10021 USA. Oak Ridge Natl Lab, Life Sci Res Div, Oak Ridge, TN 37831 USA. Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. NYU, Dept Biol, New York, NY 10003 USA. RP Patel, DJ (reprint author), Mem Sloan Kettering Canc Ctr, Cellular Biochem & Biophys Program, 1275 York Ave, New York, NY 10021 USA. EM pateld@mskcc.org; broyde@nyu.edu RI Gorin, Andrey/B-1545-2014 FU NCI NIH HHS [CA-28038, CA-49982, CA-75449]; NIEHS NIH HHS [R01 ES009127] NR 80 TC 99 Z9 100 U1 3 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0893-228X J9 CHEM RES TOXICOL JI Chem. Res. Toxicol. PD MAY PY 1998 VL 11 IS 5 BP 391 EP 407 DI 10.1021/tx9702143 PG 17 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA ZP385 UT WOS:000073747000001 PM 9585469 ER PT J AU Chen, CB Landgraf, R Walts, AD Chan, LS Schlonk, PM Terwilliger, TC Sigman, DS AF Chen, CB Landgraf, R Walts, AD Chan, LS Schlonk, PM Terwilliger, TC Sigman, DS TI Scission of DNA at a preselected sequence using a single-strand-specific chemical nuclease SO CHEMISTRY & BIOLOGY LA English DT Article DE chemical nuclease; clonable fragments; gene V protein-1-10-phenanthroline; 1,10-phenanthroline-copper; sequence-dictated DNA scission ID GENE-V-PROTEIN; 1,10-PHENANTHROLINE COPPER-ION; EXON AMPLIFICATION; BINDING PROTEINS; RNA; SITE; BACTERIOPHAGE-F1; CLEAVAGE; H-1-NMR; COMPLEX AB Background: We were interested in developing a protocol for cleaving large DNAs specifically. Previous attempts to develop such methods have failed to work because of high levels of nonspecific background scission. Results: R-loop formation was chosen for sequence-specific targeting, a method of hybridization whereby an RNA displaces a DNA strand of identical sequence in 70% formamide using Watson-Crick base-pairing, leading to a three-stranded structure. R-loops are stabilized in aqueous solution by modifying the bases with chemical reagents. The R-loop was cleaved using a novel nuclease prepared from the Thr48-->Cys mutant of the single-strand-specific M-13 gene V protein (GVP), which was alkylated with 5-(iodoacetamido-beta-alanyl)1,10-phenanthroline. The cleavage products of the pGEM plasmid were cloned into the pCR 2.1-TOPO vector. Adenovirus 2 DNA (35.8 kb; tenfold larger than the pGEM plasmid) was also cleaved quantitatively at a preselected sequence. Conclusions: A new method for cleaving duplex DNA at any preselected sequence was developed. The cleavage method relies on the chemical conversion of M-13 GVP into a nuclease, reflecting GVP's specificity for single-stranded DNA. The GVP chimera is the first example of a semisynthetic secondary structure specific nuclease, The chemical nuclease activity of 1,10-phenanthroline-copper is uniquely suited to this technique because it oxidizes the deoxyribose moiety without generating diffusible intermediates, providing clonable DNA fragments, The protocol could be useful in generating large DNA fragments for mapping the contiguity of probes or defining the exon-intron structure of transcription units. C1 Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Chicago, Dept Biochem, Chicago, IL 60637 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Sigman, DS (reprint author), Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 FU NHGRI NIH HHS [HG-00255]; NIGMS NIH HHS [GM-21199] NR 53 TC 9 Z9 9 U1 0 U2 1 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LB, ENGLAND SN 1074-5521 J9 CHEM BIOL JI Chem. Biol. PD MAY PY 1998 VL 5 IS 5 BP 283 EP 292 DI 10.1016/S1074-5521(98)90621-4 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZT622 UT WOS:000074106300007 PM 9578634 ER PT J AU Brenner, J Marshall, CL Ellis, L Tomczyk, N Heising, J Kanatzidis, M AF Brenner, J Marshall, CL Ellis, L Tomczyk, N Heising, J Kanatzidis, M TI Microstructural characterization of highly HDS-active Co6S8-pillared molybdenum sulfides SO CHEMISTRY OF MATERIALS LA English DT Article ID TRANSITION-METAL SULFIDES; MO HYDRODESULFURIZATION CATALYSTS; MOSSBAUER EMISSION-SPECTROSCOPY; S TYPE STRUCTURES; HYDROTREATING CATALYSTS; CO; CARBON; COBALT; PHASE; INTERCALATION AB In this work, we have used transmission electron microscopy (TEM) to study Co6S8(PPh3)(x)-pillared MoS2 and have directly observed that the Co clusters can either intercalate into the bulk or can bind to defect sites at the edges of MoS2. A distribution of discrete 0.87 nm scattering-centers has been assigned to remnants of the Co6S8(PPh3)(6) clusters. On the basis of X-ray diffraction (XRD) studies, a lattice expansion of 1.48 nm was expected if the triphenylphosphine ligands remained intact. The distribution of Co scattering centers, however, was consistent with that expected for a Co6S8 care (0.8 nm). The expansion of the {00l}-MoS2 planes was almost always localized about a single Co cluster, and the degree of lattice expansion (0.78 nm) was also consistent with the dimensions of the Co6S8 cores, confirming that the ligands had been nearly completely removed. The organic ligands were removed either during the vacuum pumpdown in the TEM specimen chamber or almost immediately upon electron-beam exposure. Additional electron-beam exposures of up to I h caused no further structural changes. The inorganic framework remained intact throughout the duration of the experiment. The Co6S8-pillared MoS2 materials possessed dibenzothiophene (DBT) hydrodesulfurization (HDS) activities that were slightly better than that of a commercial sulfided Co-Mo/Al2O3 catalyst under low-severity HDS conditions. However, the selectivity to biphenyl was somewhat poorer than that of commercial Go-Mo and Ni-Mo catalysts under all conditions examined. The HDS and TEM results suggest that the role of Co in sulfided Go-Mo catalysts is to prop apart MoS2 layers, creating a higher percentage of "rim" sites (in the Daage-Chianelli terminology) and enhancing hydrogenation capability. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Fundamental Mat Res, E Lansing, MI 48824 USA. RP Marshall, CL (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Marshall, Christopher/D-1493-2015 OI Marshall, Christopher/0000-0002-1285-7648 NR 62 TC 32 Z9 32 U1 0 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1998 VL 10 IS 5 BP 1244 EP 1257 DI 10.1021/cm970592t PG 14 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZP381 UT WOS:000073746600009 ER PT J AU Cormier, RA Gregg, BA AF Cormier, RA Gregg, BA TI Synthesis and characterization of liquid crystalline perylene diimides SO CHEMISTRY OF MATERIALS LA English DT Article ID THIN-FILMS; DERIVATIVES; PORPHYRIN; PHTHALOCYANINE; MECHANISM; ETHERS; PHASE; CELLS; DYES AB Several polyoxyethylene-substituted perylene-3,4,9,10-tetracarboxyldiimides have been synthesized and characterized. Relative to other known perylene diimide derivatives, all of the present compounds have much lower melting-points and much greater solubility in common solvents. Most of these compounds possess liquid crystalline properties over a wide range of temperatures, some of them even at room temperature and below. Some of the photophysical and self-organizing characteristics of these compounds are demonstrated, particularly with regard to the spontaneous formation of a highly crystalline black phase. Generalized correlations about the physical properties and the chemical structures of these new liquid crystalline compounds are discussed. Their unusual physical and photophysical properties have important implications for their use in a variety of electroactive and photovoltaic applications. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Metropolitan State Coll, Dept Chem, Denver, CO 80204 USA. RP Gregg, BA (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 47 TC 136 Z9 138 U1 0 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1998 VL 10 IS 5 BP 1309 EP 1319 DI 10.1021/cm970695b PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZP381 UT WOS:000073746600017 ER PT J AU Carrado, KA Xu, LQ AF Carrado, KA Xu, LQ TI In situ synthesis of polymer-clay nanocomposites from silicate gels SO CHEMISTRY OF MATERIALS LA English DT Article ID NYLON 6-CLAY HYBRID; LAYERED SILICATES; HYDROTHERMAL CRYSTALLIZATION; INTERCALATION; MONTMORILLONITE; POLY(VINYLPYRROLIDONE); COMPOSITE; COMPLEXES; BEHAVIOR; MICA AB Polymer-containing silicate gels were hydrothermally crystallized to form layered magnesium silicate hectorite clays containing polymers that are incorporated in situ. Gels consist of silica sol, magnesium hydroxide sol, lithium fluoride, and the polymer of choice. Dilute solutions of gel in water are refluxed for various lengths of time and then isolated via centrifugation, washed, and air-dried. Polymer loadings up to 86% were attained by adding more polymer to the solutions after a-day reaction times, reacting for another 24 h, and continuing this process prior to isolation. Polyaniline(PANI)- and polyacrylonitrile (PACN)clay samples contain up to 57% and 76% polymer, respectively, after just one sequential addition at high polymer loading. Series of PANI-, PACN-, poly(vinylpyrrolidone) (PVP)-, and hydroxypropylmethylcellulose (HPMC)-clays also were prepared by several sequential additions of lower polymer loading to the silicate gel during crystallization. Final polymer loadings were determined by thermal analysis. Basal spacings between clay interlayers were measured by X-ray powder diffraction for all samples. Increases in polymer loadings and basal spacings were observed for all the neutral polymers studied, until or unless delamination occured. Delamination was evident for PACN- and PANI-clay nanocomposites. The highest loadings were observed for the PACN-clays, up to 86%. For the cationic polymer polydimethyldiallylammonium chloride, however, the loading could not be increased beyond about 20%. This is due to electrostatic interactions that balance the negatively charged sites on the silicate lattice with those on the cationic polymer chain. Beyond charge compensation, there is no driving force for further incorporation. Charge compensation in the case of the neutral polymers is attained by interlayer lithium(I) cations. C1 Argonne Natl Lab, Chem Div 200, Argonne, IL 60439 USA. RP Carrado, KA (reprint author), Argonne Natl Lab, Chem Div 200, 9700 S Cass Ave, Argonne, IL 60439 USA. EM kcarrado@anl.gov NR 34 TC 152 Z9 158 U1 4 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1998 VL 10 IS 5 BP 1440 EP 1445 DI 10.1021/cm970814n PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZP381 UT WOS:000073746600034 ER PT J AU Cahill, CL Ko, YH Hanson, JC Tan, KM Parise, JB AF Cahill, CL Ko, YH Hanson, JC Tan, KM Parise, JB TI Structure of microporous QUI-MnGS-1 and in situ studies of its formation using time-resolved synchrotron x-ray powder diffraction SO CHEMISTRY OF MATERIALS LA English DT Article ID NANOPOROUS TIN(IV) SULFIDES; HYDROTHERMAL SYNTHESIS; OPEN-FRAMEWORKS; PLATE DATA AB The structure of QUI-MnGS-1 has been determined from single-crystal X-ray diffraction on a similar to 0.03 x 0.03 x 0.02 mm sample using synchrotron radiation. This material [(C7H13N)Mn0.25Ge1.75S4 . H2O] crystallizes in space group I (4) over bar 2d with unit cell a = 11.581(1) and c = 18.741(3) A. The extended framework of this structure consists of corner-linked [Ge4S10](4-) clusters, the centers of which occupy nodes of a distorted diamond lattice. The B-rings defined by this lattice form channels that contain the water and organic components of this compound. In situ synchrotron X-ray diffraction studies of its synthesis indicate that an Mn-free precursor phase forms prior to transformation to QUI-MnGS-1. In situ calcination experiments demonstrate that this material is thermally stable to approximately 360 degrees C. C1 SUNY Stony Brook, Dept Chem, New York, NY 11794 USA. SUNY Stony Brook, Dept Geosci, New York, NY 11794 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Cahill, CL (reprint author), SUNY Stony Brook, Dept Chem, New York, NY 11794 USA. RI Hanson, jonathan/E-3517-2010 NR 46 TC 31 Z9 32 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1998 VL 10 IS 5 BP 1453 EP 1458 DI 10.1021/cm980026d PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZP381 UT WOS:000073746600036 ER PT J AU Najm, HN Paul, PH Mueller, CJ Wyckoff, PS AF Najm, HN Paul, PH Mueller, CJ Wyckoff, PS TI On the adequacy of certain experimental observables as measurements of flame burning rate SO COMBUSTION AND FLAME LA English DT Article ID LASER-INDUCED FLUORESCENCE; TURBULENT PREMIXED FLAMES; NUMERICAL SIMULATIONS; VORTEX; COMBUSTION; HCO; LIFETIMES; EQUATION; STRETCH; STATE AB This work presents detailed chemical kinetic computations and experimental measurements of a premixed stoichiometric N-2-diluted methane-air flame in two-dimensional unsteady vortical Bow, which are used to investigate the utility of several experimental observables as measurements of local burning and heat release rates. The computed mole fraction of HCO is found to have excellent correlation with flame heat release rate over the whale range of unsteady curvature and strain-rate investigated, for the flame under consideration. HCO planar laser induced fluorescence (PLIF) imaging is discussed and demonstrated in a V-flame experiment. On the other hand, we find the utility of peak dilatation rate as an indicator of heat release rate to he dependent on the unsteady strain-rate and flame curvature environment, and the associated modification in diffusional thermal fluxes within the flame. The integrated dilatation rate is found to be more robust under unsteady strain-rate, but still questionable in regions of high flame curvature. We also study the utility of a particular formulation for CO2* chemiluminescence, OH, and CH PLIF imaging, as well as OH*, C-2*, and CH* chemiluminescence, as measurements of flame burning and heat release rates. We generally find these measures to be inferior to HCO. Experimental results suggest that CH, OH*, C-2*, and CH* are not adequate indicators of local extinction; rather they provide signals of subtle shifts of hydrocarbon consumption among different chemical pathways. Moreover, numerical results suggest that both OH mole fraction and an existing CO2* chemiluminescence model do not correlate with burning or heat release rate variations in regions of high unsteady flame curvature. The present numerical investigation uses a single flame/vortex condition and a specific 46-step C-(1) chemical mechanism. The conclusions reached herein may be generalized with further studies using more detailed mechanisms over ranges of stoichiometry, dilution, and flow time and spatial scales. (C) 1998 by The Combustion Institute. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Najm, HN (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 57 TC 272 Z9 277 U1 3 U2 42 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1998 VL 113 IS 3 BP 312 EP 332 DI 10.1016/S0010-2180(97)00209-5 PG 25 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA ZF805 UT WOS:000072935000003 ER PT J AU Margolis, SB AF Margolis, SB TI Hydrodynamic instability in an extended Landau/Levich model of liquid-propellant combustion at normal and reduced gravity SO COMBUSTION AND FLAME LA English DT Article ID CELLULAR FLAMES; BIFURCATION; PROPAGATION; STABILITY AB The classical Landau/Levich models of liquid-propellant combustion, despite their relative simplicity, serve as seminal examples that correctly describe the onset of hydrodynamic instability in reactive systems. Recently, these two separate models have been combined and extended to account for a dynamic dependence, absent in the original formulations, of the local burning rate on the local pressure and temperature fields. The resulting model admits an extremely rich variety of both hydrodynamic and reactive/diffusive instabilities that can be analyzed either numerically or analytically in various limiting parameter regimes. In the present work, a formal asymptotic analysis, based on the realistic smallness of the gas-to-liquid density ratio, is developed to investigate the combined effects of gravity and other parameters on the hydrodynamic instability of the propagating liquid/gas interface. In particular, an analytical expression is derived for the neutral stability boundary A(p)(k), where A(p) is the pressure sensitivity of the burning rate and k is the wavenumber of the disturbance. The results demonstrate explicitly the stabilizing effect of gravity on long-wave disturbances, the stabilizing effect of viscosity (both liquid and gas) and surface tension on short-wave perturbations, and the instability associated with intermediate wavenumbers for critical negative values of A(p). In the limiting case of weak gravity, it is shown that hydrodynamic instability in liquid-propellant combustion is a long-wave instability phenomenon, whereas at normal gravity, this instability is first manifested through O(1) wavenumber disturbances. It is also demonstrated that, in general, surface tension and the viscosity of both the liquid and gas phases each produce comparable stabilizing effects in the large-wavenumber regime, thereby providing important modifications to previous analyses in which one or more of these effects were neglected. (C) 1998 by The Combustion Institute. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Margolis, SB (reprint author), Sandia Natl Labs, Combust Res Facil, MS 9052, Livermore, CA 94551 USA. NR 16 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1998 VL 113 IS 3 BP 406 EP 423 DI 10.1016/S0010-2180(97)00221-6 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA ZF805 UT WOS:000072935000010 ER PT J AU Dodelson, S AF Dodelson, S TI The Big Bang SO COMMENTARY LA English DT Letter C1 NASA, Fermilab Astrophys Ctr, Batavia, IL USA. RP Dodelson, S (reprint author), NASA, Fermilab Astrophys Ctr, Batavia, IL USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER JEWISH COMMITTEE PI NEW YORK PA 165 E 56TH ST, NEW YORK, NY 10022 USA SN 0010-2601 J9 COMMENTARY JI Commentary PD MAY PY 1998 VL 105 IS 5 BP 5 EP 6 PG 2 WC Political Science; Social Issues SC Government & Law; Social Issues GA ZJ592 UT WOS:000073232200001 ER PT J AU Nagle, RD Burke, VJ Congdon, JD AF Nagle, RD Burke, VJ Congdon, JD TI Egg components and hatchling lipid reserves: Parental investment in kinosternid turtles from the southeastern United States SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY LA English DT Article DE egg; hatchlings; iatroscan; Kinosternon; lipids; parental investment; reptiles; Sternotherus; TLC-FID; turtles ID FATTY-ACID COMPOSITION; EVOLUTIONARY SIGNIFICANCE; REPRODUCTIVE-CYCLE; STERNOTHERUS-MINOR; UTA-STANSBURIANA; YOLK; SIZE; LIZARD; ENERGY; SELECTION AB We measured egg components and pre-ovulatory parental investment in kinosternid turtles (Kinosternon baurii, Kinosternon subrubrum, Sternotherus minor, and Sternotherus odoratus) from the southeastern USA. Allocation patterns were determined by comparing lipid content of eggs and hatchlings, to determine whether females of species with hatchlings that exhibit a delayed nest-emergence strategy: (1) allocate higher proportions of energy storage lipids to eggs, (2) produce hatchlings with higher levels of storage lipids, and (3) have higher levels of pre-ovulatory parental investment in comparison to species whose hatchlings exhibit immediate emergence. Whereas total non-polar lipid (NPL) proportions by dry mass of eggs varied significantly among species, NPL proportions of hatchlings were not significantly different. Pre-ovulatory parental investment in care (proportion of hatchling NPL to egg NPL) was 40, 50, and 55% for K. subrubrum, S. minor, and S. odoratus, respectively. Lipid class composition of eggs and hatchlings was studied to distinguish lipids allocated for energy storage from those allocated to other functions. For both eggs and hatchlings, individual lipid classes (triacylglycerol, triacylglycerol fatty acid, cholesterol, cholesterol ester, and phospholipid) as proportions of total lipid, were similar among species. The major lipid class component of eggs and hatchlings of all species was triacylglycerol (> 83%), an energy storage lipid. Substantial changes in lipid classes during embryogenesis were similar among species and included: (1) depletion of triacylglycerol, (2) increase in cholesterol esters, and (3) changes in phospholipid composition. Incubation time varied significantly among species, and appeared to be responsible for differential energy utilization during embryogenesis. Our results are inconsistent with the previously observed pattern that hatchlings exhibiting a delayed nest-emergence strategy are allocated higher proportions of energy storage lipids than those that exhibit immediate emergence. However, because the species that overwinters in the nest (K. subrubrum) hatches approximately 40 days later than the species that typically does not (S. odoratus), hatchling K, subrubrum may contain higher non-polar lipid proportions than hatchling S. odoratus during similar winter time periods. Kinosternid hatchlings contain enough stored lipids to support basal maintenance costs for substantial time periods. We suggest that such reserves may be critical to hatchling survival during a period of negative energy balance, regardless of nest emergence strategy. (C) 1998 Elsevier Science Inc. All rights reserved. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Nagle, RD (reprint author), Juniata Coll, Brumbaugh Sci Ctr, Huntingdon, PA 16652 USA. NR 47 TC 29 Z9 30 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0305-0491 J9 COMP BIOCHEM PHYS B JI Comp. Biochem. Physiol. B-Biochem. Mol. Biol. PD MAY PY 1998 VL 120 IS 1 BP 145 EP 152 DI 10.1016/S0305-0491(98)10003-2 PG 8 WC Biochemistry & Molecular Biology; Zoology SC Biochemistry & Molecular Biology; Zoology GA 116UA UT WOS:000075742200013 PM 9787783 ER PT J AU Wolbers, S AF Wolbers, S TI Strategic directions of computing at Fermilab SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY AB Fermilab computing has changed a great deal over the years, driven by the demands of the Fermilab experimental community to record and analyze larger and larger datasets, by the desire to take advantage of advances in computing hardware and software, and by the advances coming from the R&D efforts of the Fermilab Computing Division. The strategic directions of Fermilab Computing continue to be driven by the needs of the experimental program. The current fixed-target run will produce over 100 TBytes of raw data and systems must be in place to allow the timely analysis of the data. The collider run II, beginning in 1999, is projected to produce of order 1 PByte of data per year. There will be a major change in methodology and software language as the experiments move away from FORTRAN and into object-oriented languages. Increased use of automation and the reduction of operator-assisted tape mounts will be required to meet the needs of the large experiments and large data sets. Work will continue on higher-rate data acquisition systems for future experiments and projects. R&D projects will be pursued as necessary to provide software, tools, or systems which cannot be purchased or acquired elsewhere. A closer working relation with other high energy laboratories will be pursued to reduce duplication of effort and to allow effective collaboration on many aspects of HEP computing. (C) 1998 Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Wolbers, S (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 18 EP 21 DI 10.1016/S0010-4655(97)00147-1 PG 4 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300006 ER PT J AU Lammel, S AF Lammel, S TI Computing models of CDF and DO in Run II SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY ID DETECTOR AB The next collider run of the Fermilab Tevatron, Run II, is scheduled for autumn of 1999. Both experiments, the Collider Detector at Fermilab (CDF) and the Dempty set experiment are being modified to cope with the higher luminosity and shorter bunchspacing of the Tevatron. New detector components, higher event complexity, and an increased data volume require changes from the data acquisition systems up to the analysis systems. In this paper we present a summary of the computing models of the two experiments for Run II. (C) 1998 Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Lammel, S (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 32 EP 37 DI 10.1016/S0010-4655(97)00150-1 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300009 ER PT J AU Desmond, E Haggerty, J Kehayias, HJ Kozlowski, T Purschke, ML Witzig, C AF Desmond, E Haggerty, J Kehayias, HJ Kozlowski, T Purschke, ML Witzig, C TI PHENIX on-line distributed computing system architecture SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE C++; distributed control systems; CORBA; CASE AB PHENIX is one of the two large experiments at the Relativistic Heavy Ion Collider (RHIC) currently under construction at Brookhaven National Laboratory, The detector consists of 11 subdetectors, that are further subdivided into 29 units ("granules") that can be operated independently, which includes simultaneous data taking with independent data streams and independent triggers. The detector has 250 000 channels and is read out by front-end modules, where the data is buffered in a pipeline while awaiting the level1 trigger decision. Zero suppression and calibration is done after the level1 accept in custom built data collection modules (DCMs) with DSPs before the data is sent to an event builder (design throughput of 2 Gb/sec) and higher level triggers. The On-line Computing Systems Group (ONCS) has two responsibilities. Firstly, it is responsible for receiving the data from the event builder, routing it through a network of workstations to consumer processes and archiving it at a data rate of 20 MB/sec. Secondly, it is also responsible for the overall configuration, control and operation of the detector and data acquisition chain, which comprises the software integration for several thousand custom built hardware modules. The software must furthermore support the independent operation of the above mentioned granules, which includes the coordination of processes that run in 60-100 VME processors and workstations. ONCS has adapted the Shlaer-Mellor Object Oriented Methodology for the design of the top layer software. CORBA is used as communication layer between the distributed objects, which are implemented as asynchronous finite state machines. We will give an overview of the PHENIX online system with the main focus on the system architecture, software components and integration tasks of the On-line Computing group ONCS and report on the status of the current prototypes. (C) 1998 Elsevier Science B.V. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. RP Desmond, E (reprint author), Brookhaven Natl Lab, Dept Phys, Bldg 510C,POB 5000, Upton, NY 11973 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 107 EP 112 DI 10.1016/S0010-4655(97)00162-8 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300021 ER PT J AU Malon, DM May, EN AF Malon, DM May, EN TI An ODMG-compatible testbed architecture for scalable management and analysis of physics data SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE object-oriented databases; object persistence; multilevel storage management; ODMG AB This paper describes a testbed architecture for the investigation and development of scalable approaches to the management and analysis of massive amounts of high energy physics data. The architecture has two components: an interface layer that is compliant with a substantial subset of the ODMG-93 Version 1.2 specification, and a lightweight object persistence manager that provides flexible storage and retrieval services on a variety of single- and multi-level storage architectures, and on a range of parallel and distributed computing platforms. Published by Elsevier Science B.V. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Malon, DM (reprint author), Argonne Natl Lab, 9700 S Cass Ave,Bldg 900, Argonne, IL 60439 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 120 EP 124 DI 10.1016/S0010-4655(97)00164-1 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300023 ER PT J AU Agarwal, DA Sachs, SR Johnston, WE AF Agarwal, DA Sachs, SR Johnston, WE TI The reality of collaboratories SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE collaboratory; remote access; spectro-microscopy; telepresence; electronic notebooks; experiments on-line AB Advances in data acquisition and dissemination technologies, together with several other computer science technologies, provide an opportunity to define new environments for remote access to scientific instruments and collaboration between researchers at remote sites. These environments, called "collaboratories" (V.G. Cerf, National Collaboratories: Applying Information Technologies for Scientific Research (National Academy Press, D.C. Washington, 1993)), are intended to provide complete location-independent collaborative access to instruments, data acquisition and analysis resources, as well as to collaborating researchers. Over the past two years we have built a prototype collaboratory at the Spectro-Microscopy Facility of the Advanced Light Source (ALS) Beamline 7.0 at Lawrence Berkeley National Laboratory. The scientists who use the Beamline are based at different cities around the world. Before the introduction of the collaboratory, experiments at the Beamline required that multiple researchers travel to Berkeley, CA. With the collaboratory, scientists can now discuss experiments with other scientists around the world and at the Beamline, "walk" around the Beamline using remotely controlled cameras, access data as it is taken, monitor instrument parameters, and do limited control of the experiment from their offices. This paper presents the design of the prototype Spectro-Microscopy Collaboratory, and the lessons learned in providing remote access to the facility. It also presents the software architecture and components that are being developed to provide a toolkit for bringing future experimental equipment on-line. (C) 1998 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Agarwal, DA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 13 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 134 EP 141 DI 10.1016/S0010-4655(97)00167-7 PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300026 ER PT J AU Cottrell, RLA Logg, CA Martin, DE AF Cottrell, RLA Logg, CA Martin, DE TI What is the Internet doing? Performance and reliability monitoring for the HEP community SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE Wide Area Networking; Internet; monitoring; end-to-end; performance; ICMP; IP; ping AB Collaborative HEP research is dependent on good Internet connectivity. Although most local- and wide-area networks are carefully watched, there is little monitoring of connections that cross many networks. 'Work is in progress at several sites to monitor Internet end-to-end performance between hundreds of HEP sites worldwide, At each collection site, ICMP ping packets are automatically sent periodically to sites of interest. The data is recorded and made available to analysis nodes, which collect the data from multiple collection sites and provide analysis and graphing. Future work includes improving the efficiency and accuracy of ping data collection. (C) 1998 Elsevier Science B.V. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Fermi Natl Accelerator Lab, HEP Network Resource Ctr, Batavia, IL 60510 USA. RP Cottrell, RLA (reprint author), Stanford Linear Accelerator Ctr, 2575 Sand Hill Rd, Stanford, CA 94309 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 142 EP 148 DI 10.1016/S0010-4655(97)00168-9 PG 7 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300027 ER PT J AU Roediger, GA Lidinsky, WP AF Roediger, GA Lidinsky, WP TI The multi-session bridge SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE video; conference; MBone; multimedia; collaboration AB The Multicast BackbONE (MBone) is heavily used to carry Internet video conferences. The low cost and ease-of-use have made the MBone and its associated tools such as sdr, vat, vie, and wb very popular. But HEP video conferences often require many-to-many sparse network topologies, an arrangement that cannot easily take advantage of MBone efficiencies. Moreover, many HEP sites do not support multicast and thus researchers at those sites are cut off from important meetings. In addition, the topology of the MBone can cause poor performance or lack of access for some sites. To solve these problems, HEPNRC has developed the Multi-Session Bridge (msb) and its companion tool vtc, The msb allows an arbitrary number of multicast and unicast sessions to be connected in one or more seamless video conferences. Multiple msb's can also be connected to form a conference virtual network. The msb also extends MBone sessions to non-MBone sites through unicast streams. The msb is being extended to provide secure communications. (C) 1998 Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, HEP Network Resource Ctr, Batavia, IL 60510 USA. RP Roediger, GA (reprint author), Fermi Natl Accelerator Lab, HEP Network Resource Ctr, POB 500, Batavia, IL 60510 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 149 EP 154 DI 10.1016/S0010-4655(97)00169-0 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300028 ER PT J AU Coperchio, MC Donszelmann, M de Groot, N Gunnarsson, P Litmaath, M McNally, D Smirnov, N AF Coperchio, MC Donszelmann, M de Groot, N Gunnarsson, P Litmaath, M McNally, D Smirnov, N TI WIRED - World-Wide Web interactive remote event display SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE HEP event displays; WWW; Java; CORBA AB WIRED (World-Wide Web Interactive Remote Event Display) is a framework, written in the Java(TM) language, for building High Energy Physics event displays. An event display based on the WIRED framework enables users of a HEP collaboration to visualise and analyse events remotely using ordinary WWW browsers, on any type of machine. In addition, event displays using WIRED may provide the general public with access to the research of high energy physics. The recent introduction of the object-oriented Java(TM) language enables the transfer of machine independent code across the Intemet, to be safely executed by a Java enhanced WWW browser. We have employed this technology to create a remote event display in WWW. The combined Java-WWW technology hence assures a world wide availability of such an event display, an always up-to-date program and a platform independent implementation, which is easy to use and to install. (C) 1998 Elsevier Science B.V. C1 Univ Bologna, Dipartmento Fis, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. CERN, CH-1211 Geneva, Switzerland. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Stockholm, Fysikum, S-11385 Stockholm, Sweden. Protvino High Energy Phys Inst, Protvino 142284, Russia. RP Coperchio, MC (reprint author), Univ Bologna, Dipartmento Fis, Via Irnerio 46, I-40126 Bologna, Italy. RI de Groot, Nicolo/A-2675-2009 NR 16 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 155 EP 159 DI 10.1016/S0010-4655(97)00170-7 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300029 ER PT J AU Kozlowski, T Desmond, E Haggerty, J Kehayias, HJ Purschke, M Witzig, C AF Kozlowski, T Desmond, E Haggerty, J Kehayias, HJ Purschke, M Witzig, C TI Analysis, design, and implementation of PHENIX on-line computing systems software using Shlaer-Mellor object-oriented analysis and recursive design SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE OOA; OOD; object-oriented; Shlaer-Mellor; C++; PHENOL AB An early prototype of the core software for on-line computing systems for the PHENIX detector at RHIC has been developed using the Shlaer-Mellor OOA/RD method, including the automatic generation of C++ source code using a commercial translation engine and "architecture". (C) 1998 Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Grp P25, Los Alamos, NM 87545 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kozlowski, T (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, Grp P25, MS-H846, Los Alamos, NM 87545 USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 164 EP 169 DI 10.1016/S0010-4655(97)00172-0 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300031 ER PT J AU White, V AF White, V TI MISCOMP - an information system tool-kit SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE databases; object server; C++; Java AB MISCOMP, a business data information system, has been built with an object oriented design using a client-server framework. It uses both relational and object databases for persistent data storage. It has pioneered the use of an electronic data management and workflow system and has implemented part of the system in C++. (C) 1998 Published by Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP White, V (reprint author), Fermi Natl Accelerator Lab, POB 500,Kirk & Wilson Rd,MS368, Batavia, IL 60510 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 177 EP 180 DI 10.1016/S0010-4655(97)00174-4 PG 4 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300033 ER PT J AU Cudzewicz, R Giacchetti, L Leininger, M Levshina, T Pasetes, R Schweitzer, M Wolbers, S AF Cudzewicz, R Giacchetti, L Leininger, M Levshina, T Pasetes, R Schweitzer, M Wolbers, S TI Next generation farms at Fermilab SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computing in High Energy Physics (CHEP 97) CY APR 07-11, 1997 CL BERLIN, GERMANY DE computing farms; large systems; parallel processing AB The current generation of UNIX farms at Fermilab are rapidly approaching the end of their useful life. The workstations were purchased during the years 1991-1992 and represented the most cost-effective computing available at that time. Acquisition of new workstations has been made to upgrade the UNIX farms for the purpose of providing large amounts of computing for reconstruction of data collected at the 1996-1997 fixed-target run, as well as to provide simulation computing for CMS, the Auger project, accelerator calculations and other projects that require massive amounts of CPU. (C) 1998 Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Cudzewicz, R (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1998 VL 110 IS 1-3 BP 211 EP 215 DI 10.1016/S0010-4655(97)00179-3 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZX588 UT WOS:000074533300038 ER PT J AU Casper, TA Howard, B Hunt, R Meyer, WH Moller, JM McHarg, B Henline, P Keith, K Greene, K Davis, S Barnes, D Gibney, T Roney, P Greenwood, D AF Casper, TA Howard, B Hunt, R Meyer, WH Moller, JM McHarg, B Henline, P Keith, K Greene, K Davis, S Barnes, D Gibney, T Roney, P Greenwood, D TI Remote experimental environment: Building a collaboratory for fusion research SO COMPUTERS IN PHYSICS LA English DT Article C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Gen Atom Co, San Diego, CA 92121 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Casper, TA (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0894-1866 J9 COMPUT PHYS JI Comput. Phys. PD MAY-JUN PY 1998 VL 12 IS 3 BP 220 EP + DI 10.1063/1.168665 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Computer Science; Physics GA ZU254 UT WOS:000074178200006 ER PT J AU Furnish, G AF Furnish, G TI Container-free numerical algorithms in C++ SO COMPUTERS IN PHYSICS LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Furnish, G (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. NR 10 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0894-1866 J9 COMPUT PHYS JI Comput. Phys. PD MAY-JUN PY 1998 VL 12 IS 3 BP 258 EP + DI 10.1063/1.168674 PG 7 WC Computer Science, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Computer Science; Physics GA ZU254 UT WOS:000074178200012 ER PT J AU Wilets, L Cohen, JS AF Wilets, L Cohen, JS TI Fermion molecular dynamics in atomic, molecular, and optical physics SO CONTEMPORARY PHYSICS LA English DT Review ID ANTIPROTONIC HELIUM-ATOMS; MANY-BODY MODEL; METASTABLE STATES; DOUBLE-IONIZATION; COLLISIONS; SIMULATIONS; HEISENBERG AB Classical dynamics, often called 'molecular dynamics' when applied to atoms and molecules, is much easier than solving the many-body Schrodinger equation for a number of reasons. In particular, correlation and rearrangement are simple in classical dynamics. Fermion molecular dynamics (FMD) is a quasi-classical method for treating quantum-mechanical systems using classical equations of motion with momentum-dependent model potentials added to rite usual Hamiltonian. These model potentials constrain the motion to satisfy the Heisenberg uncertainty and the Pauli exclusion principles. We discuss the foundations of the FMD model and its applications to atomic and molecular structure, ion-atom collisions, stopping powers, formation of antiprotonic atoms, and multiple ionization of atoms in strong laser fields. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Wilets, L (reprint author), Univ Washington, Dept Phys, Box 351560, Seattle, WA 98195 USA. NR 32 TC 25 Z9 25 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0010-7514 J9 CONTEMP PHYS JI Contemp. Phys. PD MAY-JUN PY 1998 VL 39 IS 3 BP 163 EP 175 DI 10.1080/001075198181991 PG 13 WC Physics, Multidisciplinary SC Physics GA ZX957 UT WOS:000074572400001 ER PT J AU Heddle, DP AF Heddle, DP TI The hot views graphics library SO DR DOBBS JOURNAL LA English DT Article C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MILLER FREEMAN, INC PI SAN FRANCISCO PA 600 HARRISON ST,, SAN FRANCISCO, CA 94107 USA SN 1044-789X J9 DR DOBBS J JI Dr. Dobbs J. PD MAY PY 1998 VL 23 IS 5 BP 92 EP + PG 5 WC Computer Science, Software Engineering SC Computer Science GA ZE660 UT WOS:000072816900028 ER PT J AU Dixon, PM Olsen, AR Kahn, BM AF Dixon, PM Olsen, AR Kahn, BM TI Measuring trends in ecological resources SO ECOLOGICAL APPLICATIONS LA English DT Editorial Material DE change; environmental sampling; monitoring; regional extrapolation; survey design C1 US EPA, Natl Hlth & Environm Effects Lab, Res Triangle Pk, NC 27711 USA. ESA, Sustainable Biosphere Initiat, F-75738 Paris 15, France. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Dixon, PM (reprint author), Ecol Soc Amer, Reprint Dept, 2010 Massachusetts Ave NW,Suite 400, Washington, DC 20036 USA. NR 0 TC 18 Z9 20 U1 1 U2 5 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD MAY PY 1998 VL 8 IS 2 BP 225 EP 227 DI 10.1890/1051-0761(1998)008[0225:MTIER]2.0.CO;2 PG 3 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA ZL573 UT WOS:000073447900001 ER PT J AU Philippi, TE Dixon, PM Taylor, BE AF Philippi, TE Dixon, PM Taylor, BE TI Detecting trends in species composition SO ECOLOGICAL APPLICATIONS LA English DT Article; Proceedings Paper CT Workshop on Ecological Resource Monitoring - Change and Trend Detection CY MAY 01-03, 1996 CL LAUREL, MD SP Sustainable Biosphere Initiat, Ecol Soc Amer, Ecol Soc Amer, Stat Ecol Sect, Amer Stat Assoc, Stat & Environ Sect DE community change; dissimilarity; multidimensional scaling; ordination; randomization tests; species composition; temporal differences; trends ID COMMUNITY STRUCTURE; SIMILARITY INDEXES; DIVERSITY; POPULATIONS; ORDINATION; SUCCESSION; INTEGRITY; GRADIENT; DYNAMICS; IMPACTS AB Species composition reflects a combination of environmental and historical events at a site; hence, changes in species composition can provide a sensitive measure of ecologically relevant changes in the environment. Here, we consider the analysis of species composition when multiple sites are followed through time. Analyses of temporal trends in species composition either summarize species composition into a few metrics (indices or axis scores) or analyze the similarity among sites. We develop and illustrate the similarity approach. Each pair of samples represents a pair of replicates, a pair from the same site at different times, a pair from different sites at the same time, or an unrelated pair. Differences among times can be estimated by comparing average temporal dissimilarity to average replicate dissimilarity. Temporal trends can be described by one of three statistics that measure progressive change, the correlation of temporal dissimilarity with the length of time between samples. These methods are illustrated using data on changes in a South Carolina zooplankton assemblage following disturbance, and changes in bird species composition on Skokholm Island, Wales. It is difficult to define and interpret temporal trends. Some definitions of interesting trends, like increasing divergence from another set of sample plots, place additional requirements on the sampling design. Including replicate samples or clustering sample plots and including "control" plots for comparison with sentinel sites would contribute to an understanding of changes in species composition. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 48 TC 57 Z9 59 U1 2 U2 25 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1051-0761 EI 1939-5582 J9 ECOL APPL JI Ecol. Appl. PD MAY PY 1998 VL 8 IS 2 BP 300 EP 308 PG 9 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA ZL573 UT WOS:000073447900009 ER PT J AU Buchanan, AC Britt, PF Thomas, KB AF Buchanan, AC Britt, PF Thomas, KB TI Radical chemistry under diffusional constraints: Impact of spacer molecules on the thermolysis of surface-immobilized bibenzyl SO ENERGY & FUELS LA English DT Article ID HYDROGEN DONOR MEDIA; COAL-LIQUEFACTION; MODEL COMPOUNDS; SOLID-STATE; CHAIN DECOMPOSITION; RATE CONSTANTS; BOND-CLEAVAGE; BETA-SCISSION; TETRALIN; PYROLYSIS AB Silica nanoparticle surfaces have been chemically modified to contain a molecular probe, 1,2-diphenylethane (bibenzyl), as well as a second spacer molecule of variable structure. Thermolysis kinetics and products at 400 degrees C have been determined for bibenzyl, and the impact of diffusional constraints and spacer molecular structure on the multipathway radical chemistry has been analyzed relative to fluid phases. Unimolecular homolysis rate constants, k = (7-9) x 10(-6) s(-1), are found to be independent of spacer molecular structure (naphthalene, diphenylmethane, tetralin) and similar to values measured in fluid phases, indicating the lack of a cage effect on the silica surface. However, the total rate of bibenzyl thermolysis and the resulting product selectivities are profoundly affected by both surface immobilization and the structure of the spacer molecule. Naphthalene spacers behave as "molecular walls" serving as physical barriers to bimolecular hydrogen transfer steps on the surface and augmenting the effects of diffusional constraints. In contrast, diphenylmethane spacers are found to serve as hydrogen transfer, radical relay catalysts that translocate radical sites across the surface and diminish the impact of diffusional constraints. Tetralin spacers undergo significant reaction with free-radical intermediates, selectively producing the isomeric methylindan via a chain pathway that is promoted by the restrictions on diffusion. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Buchanan, AC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 61 TC 12 Z9 12 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAY-JUN PY 1998 VL 12 IS 3 BP 649 EP 659 DI 10.1021/ef9800056 PG 11 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA ZN298 UT WOS:000073631900031 ER PT J AU Britt, PF Mungall, WS Buchanan, AC AF Britt, PF Mungall, WS Buchanan, AC TI Pyrolysis of a polymeric model of aromatic carboxylic acids in low-rank coal SO ENERGY & FUELS LA English DT Article ID CROSS-LINKING; DECARBOXYLATION; LIQUEFACTION C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Hope Coll, Dept Chem, Holland, MI 49423 USA. RP Britt, PF (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 12 TC 12 Z9 12 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAY-JUN PY 1998 VL 12 IS 3 BP 660 EP 661 DI 10.1021/ef970218f PG 2 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA ZN298 UT WOS:000073631900032 ER PT J AU Wiser, R Pickle, S Goldman, C AF Wiser, R Pickle, S Goldman, C TI Renewable energy policy and electricity restructuring: a California case study SO ENERGY POLICY LA English DT Article DE renewable energy; restructuring; energy policy ID TECHNOLOGIES; MARKET; FUTURE AB Many countries are in the process of deregulating and restructuring their electric power industries. Although the introduction of retail competition may have negative impacts on the development of renewable energy, a number of countries are establishing new programs to support these clean energy technologies. In the United States, debate has centered on three primary renewables support mechanisms: (1) the renewables portfolio standard; (2) programs funded by an electricity distribution surcharge; and (3) voluntary renewable energy purchases by electricity customers via green power marketing. California provides a good case study of the design of renewables support programs within industry restructuring because policymakers considered all three of these options during the state's restructuring proceedings. Moreover, many of the same policy options, design issues, and political conflicts that have arisen in California are likely to recur in other states and countries. Some of the most important lessons from the California experience include: (1) renewable energy and environmental advocates must clearly articulate the need and rationale for continued support of renewables; (2) cost containment and competitive neutrality concerns must be addressed head on; (3) combinations of policies are likely to be far more effective than any single renewables policy; and (4) the effectiveness of renewable energy policies developed during the restructuring process will be strongly linked to their duration and stability. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wiser, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS 90-4000, Berkeley, CA 94720 USA. NR 25 TC 21 Z9 21 U1 1 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD MAY PY 1998 VL 26 IS 6 BP 465 EP 475 DI 10.1016/S0301-4215(98)00002-0 PG 11 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA ZY033 UT WOS:000074579900003 ER PT J AU Bunde, RL Rosentreter, JJ Liszewski, MJ AF Bunde, RL Rosentreter, JJ Liszewski, MJ TI Rate of strontium sorption and the effects of variable aqueous concentrations of sodium and potassium on strontium distribution coefficients of a surficial sediment at the Idaho National Engineering Laboratory, Idaho SO ENVIRONMENTAL GEOLOGY LA English DT Article DE strontium; sodium; potassium; distribution coefficient; K(d)s; competing cations; Idaho National Engineering Laboratory ID SR-90 AB The rate of strontium sorption and the effects of variable aqueous concentrations of sodium and potassium on strontium sorption were measured as part of an investigation to determine strontium chemical transport properties of a surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. Batch experimental techniques were used to determine the rate of strontium sorption and strontium distribution coefficients (K(d)s) between aqueous and solid phases. Rate experiments indicate that strontium in solution reached an apparent equilibrium with the sediment in 26 h. KdS were derived using the linear isotherm model at initial sodium concentrations from 100 to 5,000 mg/l and initial potassium concentrations from 2 to 150 mg/l. KdS ranged from 56 +/- 2 to 62 +/- 3 ml/g at initial aqueous concentrations of sodium and potassium equal to or less than 300 and 150 mg/l, respectively. KdS ranged from 4.7 +/- 0.2 to 19 +/- 1 ml/g with initial aqueous concentrations of sodium between 1,000 and 5,000 mg/l. These data indicate that sodium concentrations greater than 300 mg/l in wastewater increase the availability of strontium for transport beneath waste disposal ponds at the INEL by decreasing strontium sorption on the surficial sediment. Wastewater concentrations of sodium and potassium less than 300 and 150 mg/l, respectively, have little effect on the availability of strontium for transport. C1 US Geol Survey, Idaho Falls, ID 83403 USA. Idaho State Univ, Dept Chem, Pocatello, ID 83209 USA. RP Liszewski, MJ (reprint author), US Geol Survey, POB 2230, Idaho Falls, ID 83403 USA. NR 18 TC 8 Z9 8 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0943-0105 J9 ENVIRON GEOL JI Environ. Geol. PD MAY PY 1998 VL 34 IS 2-3 BP 135 EP 142 PG 8 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA ZQ055 UT WOS:000073816900008 ER PT J AU Lyons, WB Wayne, DM Warwick, JJ Doyle, GA AF Lyons, WB Wayne, DM Warwick, JJ Doyle, GA TI The Hg geochemistry of a geothermal stream, Steamboat Creek, Nevada: natural vs. anthropogenic influences SO ENVIRONMENTAL GEOLOGY LA English DT Article DE mercury; gold mining; Steamboat Creek, Nevada ID MERCURY CONTAMINATION; CARSON RIVER; TRACE-METALS; WATER; LAKE; CALIFORNIA; POLLUTION; SYSTEMS; USA AB A series of water samples from Steamboat Creek, Nevada, was analyzed for total mercury concentrations. Concentrations from these waters were 40 to 60 times higher than the pristine mountain streams entering the creek. The major source of the mercury entering Steamboat Creek is probably from gold/silver processing that took place in the 1960s. C1 Univ Alabama, Dept Geol, Tuscaloosa, AL 35487 USA. Los Alamos Natl Lab, Div Chem & Laser Sci, Los Alamos, NM 87545 USA. Univ Nevada, Hydrol Sci Program, Reno, NV 89512 USA. Shepherd Miller Inc, Ft Collins, CO 80525 USA. RP Lyons, WB (reprint author), Univ Alabama, Dept Geol, Tuscaloosa, AL 35487 USA. NR 31 TC 17 Z9 18 U1 0 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0943-0105 J9 ENVIRON GEOL JI Environ. Geol. PD MAY PY 1998 VL 34 IS 2-3 BP 143 EP 150 PG 8 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA ZQ055 UT WOS:000073816900009 ER PT J AU Crockett, AB AF Crockett, AB TI Background levels of metals in soils, McMurdo Station, Antarctica SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article ID BENTHIC MARINE POLLUTION; CONTAMINATION AB McMurdo Station is the largest research station in Antarctica, with a population that ranges each year from 250 to 1200 people. Because of its size and 40-year history of use, a number of locations around the station have become contaminated with wastes. Soils and sediments in these areas have been shown to contain elevated levels of petroleum-related products, PCBs, other organics, and metals. While some remedial investigations have been conducted, background levels of metals in soils have not been determined. This paper reports on background levels of metals in a natural basalt-derived soil ('gray soil') and scoria (soft porous rock used as fill, 'red soil') near McMurdo Station using two fundamentally different analytical procedures, concentrated acid extraction/analysis and total metals. These data facilitate determining the extent and levels of metal contamination near McMurdo Station and provide reference levels of metals for comparison with existing and future remediation data. There were statistically significant differences between metals concentrations in both gray and red soils, and no correlations between the level of extracted versus total metal. Generally, only a small fraction of a metal was extractable. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Crockett, AB (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 19 TC 21 Z9 22 U1 0 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-6369 J9 ENVIRON MONIT ASSESS JI Environ. Monit. Assess. PD MAY PY 1998 VL 50 IS 3 BP 289 EP 296 DI 10.1023/A:1005837100718 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZL096 UT WOS:000073398400007 PM 26205417 ER PT J AU Happell, JD Wallace, DWR AF Happell, JD Wallace, DWR TI Removal of atmospheric CCl4 under bulk aerobic conditions in groundwater and soils SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CARBON-TETRACHLORIDE; ORGANIC-COMPOUNDS; SHALLOW GROUNDWATER; ANAEROBIC CONDITION; CHEMICAL EVOLUTION; NORTHERN FLORIDA; COASTAL-PLAIN; SINKHOLE LAKE; WATER MASSES; CHLOROFLUOROCARBONS AB Measured concentrations of relatively nonreactive, anthropogenic halocarbon tracers (CFC-11, CFC-12, CFC-113) were used to infer the time since recharge, or age, of groundwater collected from the Upper Glacial and Magothy Aquifers underlying Brookhaven National Laboratory on Long island, NY. On the basis of the reconstructed historical atmospheric concentrations of CCl4, the initial CCl4 concentration for the precipitation that recharged the aquifer was estimated as a function of age. Correlation of measured and estimated initial CCl4 concentrations within the aquifer, over inferred ages of 0-50 yr, suggested that CCl4 was being removed in situ with a half-life of 14 +/- 4 yr. Groundwater samples collected at the water table had CCl4 concentrations that were less than or equal to 50% of equilibrium with contemporary atmospheric concentrations, suggesting that removal was also significant in the unsaturated zone. Soil gas profiles confirmed that atmospheric CCl4 was being removed from the unsaturated zone, with only similar to 25% of the initial CCl4 being present in the gas phase at a depth of 30 cm, and with no evidence for removal of CFC-11, CFC-12, or CFC-113. A time-series of soil gas profiles collected before and after a major rainfall event indicated that most removal occurred in the top 15 cm of soil. The flux of CCl4 into the soil was estimated to be similar to 8600 +/- 5100 pmol m(-2) d(-1), and removal of CCl4 in soils therefore has the potential to significantly affect the global atmospheric lifetime of this compound. The observed degradation in bulk aerobic environments raises questions concerning the conventional wisdom that CCl4 is degraded significantly only within reducing environments. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Oceanog & Atmospher Sci, Upton, NY 11973 USA. RP Happell, JD (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Tritium Lab, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. EM jhappell@rsmas.maimi.edu NR 50 TC 12 Z9 12 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 1998 VL 32 IS 9 BP 1244 EP 1252 DI 10.1021/es970653o PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZL156 UT WOS:000073404400030 ER PT J AU Les, CM Stover, SM Taylor, KT Keyak, JH Willits, NH AF Les, CM Stover, SM Taylor, KT Keyak, JH Willits, NH TI Ex vivo simulation of in vivo strain distributions in the equine metacarpus SO EQUINE VETERINARY JOURNAL LA English DT Article DE horse; metacarpus; bone; mechanical testing ID 3RD METACARPAL; BONE STRAIN; BREAKING STRENGTH; LONG BONES; HORSE; INVIVO; STRESS; AGE; LOCOMOTION; FORCES AB The objective of this study was to examine several simple ex vivo loading conditions for the equine metacarpus, and to evaluate their ability to reproduce the mid-diaphyseal bone surface strain distributions previously reported in vivo at the walk and trot. Distributed axial compressive loads, and 9 different axial compressive point loads at -7.5 kN and -15 kN were applied to metacarpal-distal carpal bone preparations from 6 Thoroughbred horses, aged 1-5 years. The resulting dorsal, medial, palmar, and lateral mid-diaphyseal bone surface axial and shear strains were compared with previously reported in vivo surface strain distributions using a root mean square error (RMSE) protocol. The effects of loading condition and load magnitude on RMSE were assessed with a mixed-model analysis of variance. There were significant differences between loading conditions, and, in most cases, between load magnitudes, in the fit of the ex vivo to the in vivo strain distributions. In vivo mid-diaphyseal bone surface strain distributions at the walk can be well approximated ex vivo by a distributed axial compressive load, or by a point load positioned 0.5 cm mediad to the sagittal midline, at -7.5 kN loads. In vivo mid-diaphyseal bone surface strain distributions at the trot can be wed approximated by the -15 kN loads applied to the same locations. These simplified loading conditions can be used in designing biologically relevant loading protocols for ex vivo mechanical testing studies, as wed as in developing boundary conditions for finite element analysis. As such, these loading conditions may be considered as tools to be used as a means of replicating in vivo loading conditions during the intial design and testing stages in the development of fracture fixation devices, as web as in the theoretical mechanical analysis of the metacarpal structure. C1 Univ Calif Lawrence Livermore Natl Lab, Sch Vet Med, JD Wheat Vet Orthoped Res Lab, Dept Anat Physiol & Cell Biol, Davis, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Div Stat, Davis, CA 95616 USA. Univ Calif Irvine, Dept Orthopaed Surg, Biomech Res Lab, Irvine, CA 92868 USA. RP Les, CM (reprint author), NASA, Ames Res Ctr, Mail Stop 239-11, Moffett Field, CA 94035 USA. FU NIAMS NIH HHS [AR08180] NR 31 TC 6 Z9 7 U1 1 U2 3 PU EQUINE VETERINARY JOURNAL LTD PI NEWMARKET PA GRASEBY HOUSE, ENXING ROAD, NEWMARKET CB8 0AU, SUFFOLK, ENGLAND SN 0425-1644 J9 EQUINE VET J JI Equine Vet. J. PD MAY PY 1998 VL 30 IS 3 BP 260 EP 266 PG 7 WC Veterinary Sciences SC Veterinary Sciences GA ZL369 UT WOS:000073426000015 PM 9622329 ER PT J AU Biino, GG Groning, P AF Biino, GG Groning, P TI X-Ray Photoelectron Spectroscopy (XPS) used as a structural and chemical surface probe on aluminosilicate minerals SO EUROPEAN JOURNAL OF MINERALOGY LA English DT Article DE XPS; aluminosilicate minerals; spectroscopy; surface analysis and structure; charge correction ID NONBRIDGING OXYGEN-ATOMS; CHARGE-CORRECTION METHOD; ALKALI FELDSPARS; WESTERN ALPS; AUGER; DISSOLUTION; ELECTRON; STM AB In surface science investigations, it is often required to determine the elemental composition and the chemical bonding states of the outermost atom layers (called surface) of a solid. X-ray Photoelectron Spectroscopy (XPS) detects photoelectrons generated in the outermost atom layers, this providing a valuable tool for studying the chemical composition and chemical environment of elements at the surface of solids. The aim of this study is to provide a systematic investigation of the surface of some aluminosilicate minerals by XPS. To accomplish this task, we investigated the XPS spectra of single crystals of andalusite, kyanite, pyrope and K-feldspar and pressed powder pellets of andalusite and pyrope. XPS yields accurate and reproducible chemical information on the near surface of these minerals. Although, the chemical composition is close to stoichiometry but the composition of the cleaved kyanite surface is richer in Si. This experimental observation is consistent with the established cleavage model. The aluminosilicate mineral surfaces are made up of adsorbed C-enriched material. The shift in kinetic energy of photoelectrons makes it possible to derive qualitative information on atomic structure, but surface charging leads to difficulties in interpreting chemical states. Therefore, charging corrections in minerals are discussed to some extent. The Ols peak can be used as indicator of the chemical environment of oxygen in silicates. We were able to split the Ols peak into its main components: Al-O-Si, Si-O-Si, non-bridged oxygen and contamination layers (adventitious material). The Cls peak gives valuable information on surface-atmosphere interactions and provide evidences for microinclusions of graphite. The presence of a thick C-rich cover poses some problems for the interpretation of Scanning Force Microscopy (SFM) images collected in air or in liquid. For a quantitative interpretation of XPS spectra a larger database is necessary coupled with information collected with other surface sensitive equipment. C1 Univ Fribourg, Inst Mineral & Petrog, Perolles, CH-1700 Fribourg, Switzerland. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Fribourg, Dept Phys, CH-1700 Fribourg, Switzerland. RP Biino, GG (reprint author), Univ Fribourg, Inst Mineral & Petrog, Perolles, CH-1700 Fribourg, Switzerland. NR 46 TC 13 Z9 13 U1 3 U2 19 PU E SCHWEIZERBART'SCHE VERLAGS PI STUTTGART PA NAEGELE U OBERMILLER JOHANNESSTRASSE 3A, D 70176 STUTTGART, GERMANY SN 0935-1221 J9 EUR J MINERAL JI Eur. J. Mineral. PD MAY-JUN PY 1998 VL 10 IS 3 BP 423 EP 437 PG 15 WC Mineralogy SC Mineralogy GA ZV220 UT WOS:000074282400003 ER PT J AU Alber, T Appelshauser, H Bachler, J Bartke, J Bialkowska, H Bloomer, MA Bock, R Braithwaite, WJ Brinkmann, D Brockmann, R Buncic, P Chan, P Cramer, JG Cramer, PB Derado, I Eberlein, B Eckardt, V Eschke, J Favuzzi, C Ferenc, D Fleischmann, B Foka, P Freund, P Fuchs, M Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hoffmann, M Jacobs, P Kabana, S Kadija, K Keidel, R Kowalski, M Kuhmichel, A Lave, F Lee, JY Ljubicic, A Margetis, S Mitchell, JT Morse, R Nappi, E Odyniec, G Paic, G Panagiotou, AD Petridis, A Piper, A Posa, F Poskanzer, AM Puhlhofer, F Rauch, W Renfordt, R Retyk, W Rohrich, D Roland, G Rothard, H Runge, K Sandoval, A Schmitz, N Schmoetten, E Sendelbach, R Seyboth, P Seyerlein, J Skrzypczak, E Spinelli, P Stock, R Strobele, H Teitelbaum, L Tonse, S Trainor, TA Vasileiadis, G Vassiliou, M Vesztergombi, G Vranic, D Wenig, S Wosiek, B Zhu, X AF Alber, T Appelshauser, H Bachler, J Bartke, J Bialkowska, H Bloomer, MA Bock, R Braithwaite, WJ Brinkmann, D Brockmann, R Buncic, P Chan, P Cramer, JG Cramer, PB Derado, I Eberlein, B Eckardt, V Eschke, J Favuzzi, C Ferenc, D Fleischmann, B Foka, P Freund, P Fuchs, M Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hoffmann, M Jacobs, P Kabana, S Kadija, K Keidel, R Kowalski, M Kuhmichel, A Lave, F Lee, JY Ljubicic, A Margetis, S Mitchell, JT Morse, R Nappi, E Odyniec, G Paic, G Panagiotou, AD Petridis, A Piper, A Posa, F Poskanzer, AM Puhlhofer, F Rauch, W Renfordt, R Retyk, W Rohrich, D Roland, G Rothard, H Runge, K Sandoval, A Schmitz, N Schmoetten, E Sendelbach, R Seyboth, P Seyerlein, J Skrzypczak, E Spinelli, P Stock, R Strobele, H Teitelbaum, L Tonse, S Trainor, TA Vasileiadis, G Vassiliou, M Vesztergombi, G Vranic, D Wenig, S Wosiek, B Zhu, X CA NA35 Collaboration TI Charged particle production in proton-, deuteron-, oxygen- and sulphur-nucleus collisions at 200 GeV per nucleon SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID INTERSECTING STORAGE-RINGS; HEAVY-ION COLLISIONS; HADRON-PRODUCTION; STREAMER CHAMBER; MULTIPARTICLE PRODUCTION; TRANSVERSE-MOMENTUM; S+S COLLISIONS; SULFUR-NUCLEUS; CERN-SPS; DISTRIBUTIONS AB The transverse momentum and rapidity distributions of net protons and negatively charged hadrons have been measured for minimum bias proton-nucleus and deuteron-gold interactions, as well as central oxygen-gold and sulphur-nucleus collisions at 200 GeV per nucleon. The rapidity density of net protons at midrapidity in central nucleus-nucleus collisions increases both with target mass for sulphur projectiles and with the projectile mass for a gold target. The shape of the rapidity distributions of net protons forward of midrapidity for d+Au and central S+Au collisions is similar. The average rapidity loss is larger than 2 units of rapidity for reactions with the gold target. The transverse momentum spectra of net protons for all reactions can be described by a thermal distribution with 'temperatures' between 145+/-11 MeV (p+S interactions) and 244+/-43 MeV (central S+Au collisions). The multiplicity of negatively charged hadrons increases with the mass of the colliding system. The shape of the transverse momentum spectra of negatively charged hadrons changes from minimum bias p+p and p+S interactions to p+Au and central nucleus-nucleus collisions. The mean transverse momentum is almost constant in the vicinity of midrapidity and shows little variation with the target and projectile masses. The average number of produced negatively charged hadrons per participant baryon increases slightly from p+p, p+A to central S+S, Ag collisions. C1 Univ Washington, Seattle, WA 98195 USA. Univ Athens, Dept Phys, Athens, Greece. Univ Bari, Dipartmento Fis, Bari, Italy. Ist Nazl Fis Nucl, I-70126 Bari, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Inst Nucl Phys, Krakow, Poland. Gesell Schwerionenforsch GmbH, Darmstadt, Germany. Univ Frankfurt, Fachbereich Phys, Frankfurt, Germany. Univ Freiburg, Fak Phys, Freiburg, Germany. Univ Marburg, Fachbereich Phys, Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Rudjer Boskovic Inst, Zagreb, Croatia. RP Alber, T (reprint author), Univ Washington, Seattle, WA 98195 USA. OI SPINELLI, Paolo/0000-0001-6688-8864 NR 51 TC 81 Z9 81 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 1998 VL 2 IS 4 BP 643 EP 659 DI 10.1007/s100520050167 PG 17 WC Physics, Particles & Fields SC Physics GA ZW748 UT WOS:000074443800005 ER PT J AU Appelshauser, H Bachler, J Bailey, SJ Barnby, LS Bartke, J Barton, RA Bialkowska, H Billmeier, A Blyth, CO Bock, R Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Ferenc, D Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Huang, I Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Squier, GTA Stock, R Strobele, H Struck, C Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Vesztergombi, G Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Yates, TA Xu, N Zimanyi, J Zhu, XZ Zybert, R AF Appelshauser, H Bachler, J Bailey, SJ Barnby, LS Bartke, J Barton, RA Bialkowska, H Billmeier, A Blyth, CO Bock, R Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Ferenc, D Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Huang, I Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Squier, GTA Stock, R Strobele, H Struck, C Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Vesztergombi, G Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Yates, TA Xu, N Zimanyi, J Zhu, XZ Zybert, R TI Hadronic expansion dynamics in central Pb+Pb collisions at 158 GeV per nucleon SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID HEAVY-ION COLLISIONS; MULTISTRING MODEL VENUS; SOURCE PARAMETERS; ENERGY-FLOW; EQUILIBRATION AB Two-particle correlation functions of negative hadrons over wide phase space, and transverse mass spectra of negative hadrons and deuterons near mid-rapidity have been measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment at the CERN SPS. A novel Coulomb correction procedure for the negative two-particle correlations is employed making use of the measured oppositely charged particle correlation. Within an expanding source scenario these results are used to extract the dynamic characteristics of the hadronic source, resolving the ambiguities between the temperature and transverse expansion velocity of the source; that are unavoidable when single and two particle spectra are analysed separately. The source shape, the total duration of the source expansion, the duration of particle emission, the freeze-out temperature and the longitudinal and transverse expansion velocities are deduced. C1 Univ Heidelberg, Inst Phys, Heidelberg, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Birmingham, Birmingham, W Midlands, England. KFKI, Res Inst Particle & Nucl Phys, Budapest, Hungary. CERN, Geneva, Switzerland. Inst Nucl Phys, Krakow, Poland. Gesell Schwerionenforsch GmbH, Darmstadt, Germany. Univ Calif Davis, Davis, CA 95616 USA. Joint Inst Nucl Res, Dubna, Russia. Univ Frankfurt, Fachbereich Phys, Frankfurt, Germany. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Marburg, Fachbereich Phys, Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Univ Washington, Phys Nucl Lab, Seattle, WA 98195 USA. Yale Univ, New Haven, CT 06520 USA. Rudjer Boskovic Inst, Zagreb, Croatia. Univ Athens, Dept Phys, Athens, Greece. RP Appelshauser, H (reprint author), Univ Heidelberg, Inst Phys, Heidelberg, Germany. RI Barnby, Lee/G-2135-2010; Levai, Peter/A-1544-2014 OI Barnby, Lee/0000-0001-7357-9904; NR 46 TC 167 Z9 168 U1 1 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 1998 VL 2 IS 4 BP 661 EP 670 DI 10.1007/s100520050168 PG 10 WC Physics, Particles & Fields SC Physics GA ZW748 UT WOS:000074443800006 ER PT J AU Magowan, C Liang, J Yeung, J Takakuwa, Y Coppel, RL Mohandas, N AF Magowan, C Liang, J Yeung, J Takakuwa, Y Coppel, RL Mohandas, N TI Plasmodium falciparum: Influence of malarial and host erythrocyte skeletal protein interactions on phosphorylation in infected erythrocytes SO EXPERIMENTAL PARASITOLOGY LA English DT Article DE Plasmodium falciparum; malaria; protein phosphorylation; casein kinase; PMA, 4-beta-phorbol 12-myristate; PBS(+), phosphate-buffered saline containing 50 mu g ml(-1) leupeptin,50 mu g ml(-1) chymostatin (both obtained from Sigma, St. Louis, MO), and 1 mM Pefabloc (Boehringer Mannheim, Indianapolis, IN) ID HISTIDINE-RICH PROTEIN; SPECTRIN-ACTIN-BINDING; RED-BLOOD-CELLS; MEMBRANE; PARASITE; SURFACE; GENE; CYTOADHERENCE; ANTIGEN; KNOBS AB Phosphorylation of components of the erythrocyte membrane skeleton has major effects on the physical properties of the membrane. Infection of red cells by the protozoan parasite Plasmodium falciparum leads to a marked increase in the level of phosphorylation of red cell protein 4.1 and the insertion into the red cell skeleton of parasite-encoded phosphoproteins, including the mature-parasite-infected erythrocyte surface antigen (MESA). Because of the tight association of MESA with protein 4.1, we set out to determine the importance of this interaction and that of other parasite-encoded skeletal-associated proteins to phosphorylation of the infected red cell membrane. Our results show that neither MESA nor protein 4.1 is required for phosphorylation of its binding partner. Further, phosphorylation of MESA and protein 4.1 occurs independently of the presence of knobs, the expression of PfHRP1, or cytoadherence phenotype. In contrast to previous studies, we were unable to detect a change in the molecular weight of protein 4.1 in erythrocytes infected with cytoadherent parasite lines. In red cells infected with parasites expressing PfHRP1 (K+), MESA and protein 4.1 are substrates for a kinase with the inhibitor profile of a casein kinase. Surprisingly, however, when we examined phosphorylation of MESA and protein 4.1 in K--infected erythrocytes, we found that casein kinase I and II inhibitors had no, or greatly reduced, effectiveness, and in fact, phosphorylation of these two proteins was enhanced in some instances. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Tokyo Womens Med Coll, Dept Biochem, Tokyo 162, Japan. Monash Univ, Dept Microbiol, Clayton, Vic 3168, Australia. RP Magowan, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,MS 74-157, Berkeley, CA 94720 USA. EM cathie_magowan@macmail2.lbl.gov RI Coppel, Ross/A-6626-2008 OI Coppel, Ross/0000-0002-4476-9124 FU NIDDK NIH HHS [DK 32094] NR 36 TC 18 Z9 18 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0014-4894 J9 EXP PARASITOL JI Exp. Parasitol. PD MAY PY 1998 VL 89 IS 1 BP 40 EP 49 DI 10.1006/expr.1998.4261 PG 10 WC Parasitology SC Parasitology GA ZN503 UT WOS:000073652400006 PM 9603487 ER PT J AU Paez, TL Hunter, NF AF Paez, TL Hunter, NF TI Statistical series: Part 5 - Fundamental concepts of the bootstrap for statistical analysis of mechanical systems SO EXPERIMENTAL TECHNIQUES LA English DT Article C1 Sandia Natl Labs, Expt Struct Dynam Dept, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Engn Sci & Anal Div, Los Alamos, NM USA. RP Paez, TL (reprint author), Sandia Natl Labs, Expt Struct Dynam Dept, POB 5800, Albuquerque, NM 87185 USA. NR 7 TC 6 Z9 9 U1 0 U2 3 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 USA SN 0732-8818 J9 EXP TECHNIQUES JI Exp. Tech. PD MAY-JUN PY 1998 VL 22 IS 3 BP 35 EP 38 DI 10.1111/j.1747-1567.1998.tb01284.x PG 4 WC Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Engineering; Mechanics; Materials Science GA ZP492 UT WOS:000073758900010 ER PT J AU Cui, ST Siepmann, JI Cochran, HD Cummings, PT AF Cui, ST Siepmann, JI Cochran, HD Cummings, PT TI Intermolecular potentials and vapor-liquid phase equilibria of perfluorinated alkanes SO FLUID PHASE EQUILIBRIA LA English DT Article DE molecular simulation; vapor-liquid phase equilibria; Gibbs ensemble Monte Carlo; perfluoroalkane; critical point ID MOLECULAR-DYNAMICS; MONTE-CARLO; FLUORINATED AMPHIPHILES; CHAIN MOLECULES; CARBON-DIOXIDE; CRITICAL-POINT; N-ALKANES; SIMULATION; MONOLAYERS; FLUIDS AB We propose 2 sets of intermolecular potentials for a united atom model of linear perfluorinated alkanes in their fluid states. Configurational-bias Monte Carlo simulations in the Gibbs ensemble have been carried out to determine the vapor-liquid phase equilibria for CnF2n+2 with n = 5, 6, 7, 8, 10 and 16. Both sets of parameters yield critical temperatures which are in excellent agreement with experiment data. However, the critical densities are slightly too high for one model and slightly too low for the other. The saturated liquid densities agree with experiment to better than 5%. Variations of the critical properties with chain length show the correct scaling for both models. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. RP Cummings, PT (reprint author), Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 32 TC 83 Z9 85 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD MAY PY 1998 VL 146 IS 1-2 BP 51 EP 61 DI 10.1016/S0378-3812(98)00216-7 PG 11 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA ZX087 UT WOS:000074478100005 ER PT J AU McLean, HS Hwang, DQ Horton, RD Evans, RW Terry, SD Thomas, JC Raman, R AF McLean, HS Hwang, DQ Horton, RD Evans, RW Terry, SD Thomas, JC Raman, R TI Design and operation of a passively switched repetitive compact toroid plasma accelerator SO FUSION TECHNOLOGY LA English DT Article ID PELLET INJECTION; COMPRESSION AB The design and operation of a spheromak-like compact toroid (SCT) plasma accelerator is described. As an example application, some principles are presented for using the device as a plasma injector to fuel a tokamak plasma. The device forms and accelerates an SCT plasma. The SCT is a self-contained structure of plasma with embedded poloidal and toroidal magnetic fields and their associated currents that provide plasma confinement and structural integrity The SCT is formed in a magnetized coaxial plasma gun and then accelerated within coaxial electrodes. The typical mass of an SCT for tokamak fueling is from several tens to several hundreds of micrograms and is accelerated up to a velocity of similar to 2 X 10(5) m/s. Larger-mass SCTs can be produced, and higher velocities are possible. This is important for other applications such as space propulsion, X-ray generation, fast-opening plasma switches, and low-temperature high-density plasma simulators. The novel features of the device are as follows: (a) it can be operated in a repetitive mode, (b) the high-energy capacitor bank to form the SCT is switched by initiating breakdown with fast gas injection, (c) the required delay between formation and acceleration is achieved passively with saturable inductors that switch the high-energy accelerator capacitor bank, and (d) a drift section has been added within the toroidal field region to study cross-field propagation prior to tokamak penetration. With the device installed on the Davis Diverted Tokamak (DDT), measurements are taken to study tokamak fueling. Typical rep-rated parameters are as follows: the SCT poloidal magnetic field at the outer electrode 0.4 T the stored formation bank energy = 1600 J, and the stored accelerator bank energy = 3600 J. The lower bound on SCT kinetic energy leaving the accelerator = 40 J (inferred from electron line density measurements). Typical SCT velocity is 15 to 20 cm/mu s. The maximum rep-rate achieved so far with the device is 0.2 Hz and is currently limited by vacuum pumping capacity. Reliable operation has been demonstrated for 1000 consecutive shots. Higher-energy single shots have also been taken to study SCT propagation through an open guide tube and to study penetration of the SCT into the DDT tokamak vessel with both tokamak plasma discharges and vacuum toroidal magnetic field only. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Pulse Sci Inc, San Leandro, CA USA. Canadian Fus Fuels Technol Project, Toronto, ON, Canada. RP McLean, HS (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 15 TC 27 Z9 27 U1 0 U2 8 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD MAY PY 1998 VL 33 IS 3 BP 252 EP 272 PG 21 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZR756 UT WOS:000074010600002 ER PT J AU Latkowski, JF Vujic, JL AF Latkowski, JF Vujic, JL TI Inertial fusion energy: A clearer view of the environmental and safety aspects SO FUSION TECHNOLOGY LA English DT Article ID LOW-ACTIVATION MATERIALS; REACTORS; DESIGN; ELEMENTS; OSIRIS AB A consistent method for the comparison of environmental, safety and health (ES&H) characteristics of fusion power plant designs is developed. Such comparisons enable identification of trends infusion ES&H characteristics and can be used to increase the likelihood of fusion achieving its full potential with respect to ES&H characteristics. A large number of radiological hazard indexes are defined in three different categories of hazard: accidents, occupational and routine exposures, and waste disposal. Using a consistent set of computer codes, data libraries, and assumptions, these radiological hazard indexes are calculated and compared for five inertial and two magnetic fusion energy power plant designs. The results of the analysis are threefold: The utility of low-activation materials (LAMs) is confirmed, the tremendous potential for the use of a thick-liquid system for first-wall protection is validated, and the strong need for materials that can last for the lifetime of the power plant is shown. The conservative radionuclide release fractions that are used show that all but one of the designs has only a minute chance of producing any early fatalities during an accident. The need for remote maintenance in most designs is confirmed, and the possibility of disposing of most fusion wastes via shallow land burial (if the methodology of current regulations is applied to fusion wastes) is shown. The need for more research in LAMs and for the experimental measurement of radionuclide release fractions under accident conditions is emphasized. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. RP Latkowski, JF (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 E Ave,L-481, Livermore, CA 94550 USA. NR 64 TC 7 Z9 7 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD MAY PY 1998 VL 33 IS 3 BP 298 EP 340 PG 43 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZR756 UT WOS:000074010600006 ER PT J AU Pollard, VK Tonn, BE AF Pollard, VK Tonn, BE TI Revisiting the 'Court of Generations' Amendment - A conversation SO FUTURES LA English DT Article AB In 1991, futurist Bruce E. Tonn proposed a 'Court of Generations' Amendment to the US Constitution. His proposed 'Court of Generations' lacked punitive powers but, hopefully, would have sufficient legitimacy to counteract extreme present-minded thinking evident in US political processes and institutions. Although Tonn's 'Court of Generations' Amendment has been well received in the futures community, who else has heard of it? Otherwise, has it made any difference? How can the cumbersome and nonfuturistic amendment procedure in the US Constitution generate a futures-oriented 'Court of Generations'? And for those who sincerely look forward to a 'Court of Generations,' precisely what kind of tactically savvy visionary leadership will give the 'Court of Generations' any chance of being approved? During 1997, Vincent Kelly Pollard engaged Dr. Tonn in an Internet conversation aimed at clarifying these issues. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Hawaii, Hawaii Res Ctr Futures Studies, Honolulu, HI 96822 USA. Univ Hawaii, Dept Polit Sci, Honolulu, HI 96822 USA. Oak Ridge Natl Lab, Div Energy, Policy Anal Syst Grp, Oak Ridge, TN 37831 USA. RP Pollard, VK (reprint author), Univ Hawaii, Hawaii Res Ctr Futures Studies, Honolulu, HI 96822 USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0016-3287 J9 FUTURES JI Futures PD MAY PY 1998 VL 30 IS 4 BP 345 EP 352 DI 10.1016/S0016-3287(98)80015-3 PG 8 WC Economics; Planning & Development SC Business & Economics; Public Administration GA 123CE UT WOS:000076107600006 ER PT J AU Filippova, GN Lindblom, A Meincke, LJ Klenova, EM Neiman, PE Collins, SJ Doggett, NA Lobanenkov, VV AF Filippova, GN Lindblom, A Meincke, LJ Klenova, EM Neiman, PE Collins, SJ Doggett, NA Lobanenkov, VV TI A widely expressed transcription factor with multiple DNA sequence specificity, CTCF, is localized at chromosome segment 16q22.1 within one of the smallest regions of overlap for common deletions in breast and prostate cancers SO GENES CHROMOSOMES & CANCER LA English DT Article ID C-MYC GENE; ALLELIC IMBALANCE; DOWN-REGULATION; NONLYMPHOCYTIC LEUKEMIA; OVARIAN-CANCER; POOR-PROGNOSIS; PHYSICAL MAP; E-CADHERIN; ARM 16Q; CARCINOMAS AB The cellular protooncogene MYC encodes a nuclear transcription factor that is involved in regulating important cellular functions, including cell cycle progression, differentiation, and apoptosis. Dysregulated MYC expression appears critical to the development of various types of malignancies, and thus factors involved in regulating MYC expression may also play a key role in the pathogenesis of certain cancers. We have cloned one such MYC regulatory factor, termed CTCF, which is a highly evolutionarily conserved-11-zinc finger transcriptional factor possessing multiple DNA sequence specificity. CTCF binds to a number of important regulatory regions within the 5' noncoding sequence of the human MYC oncogene, and it can regulate its transcription in several experimental systems. CTCF mRNA is expressed in cells of multiple different lineages. Enforced ectopic expression of CTCF inhibits cell growth in culture. Southern blot analyses and fluorescence in situ hybridization (FISH) with normal human metaphase chromosomes showed that the human CTCF is a single-copy gene situated at chromosome locus 16q22. Cytogenetic studies have pointed out that chromosome abnormalities (deletions) at this locus frequently occur in many different human malignancies, suggesting the presence of one or more tumor suppressor genes in the region. To narrow down their localization, several loss of heterozygosity (LOH) studies of chromosome arm 16q in sporadic breast and prostate cancers have been carried out to define the most recurrent and smallest region(s) of overlap (SRO) for commonly deleted chromosome arm 16q material. For CTCF to be considered as a candidate tumor suppressor gene associated with tumorigenesis, it should localize within one of the SROs at 16q. Fine-mapping of CTCF has enabled us to assign the CTCF gene to about a 2 centiMorgan (cM) interval of 16q22.1 between the somatic cell hybrid breakpoints CY130(D) and CY4, which is between markers D16S186 (16AC16-101) and D16S496 (AFM214zg5). This relatively small region, containing the CTCF gene, overlaps the most Frequently observed SROs for common chromosomal deletions found in sporadic breast and prostate tumors. In one of four analyzed paired DNA samples from primary breast cancer patients, we have detected a tumor-specific rearrangement of CTCF exons encoding the I I-zinc-finger domain. Therefore, taken together with other CTCF properties, localization of CTCF to a narrow cancer-associated chromosome region suggests that CTCF is a novel candidate tumor suppressor gene at 16q22.1. (C) 1998 Wiley-Liss, Inc. C1 Fred Hutchinson Canc Res Ctr, Div Basic Sci, Seattle, WA 98109 USA. Fred Hutchinson Canc Res Ctr, Div Mol Med, Seattle, WA 98109 USA. Karolinska Hosp, Dept Clin Genet, S-10401 Stockholm, Sweden. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM USA. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM USA. Univ Oxford, Dept Biochem, Oxford OX1 3QU, England. RP Lobanenkov, VV (reprint author), Fred Hutchinson Canc Res Ctr, Div Basic Sci, 1100 Fairview Ave N,Mailstop C2-023,POB 19024, Seattle, WA 98109 USA. EM vlobanen@fred.fherc.org OI Lobanenkov, Victor/0000-0001-6665-3635 FU NCI NIH HHS [CA58292, CA68360, CA71732] NR 66 TC 103 Z9 104 U1 2 U2 5 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 1045-2257 J9 GENE CHROMOSOME CANC JI Gene Chromosomes Cancer PD MAY PY 1998 VL 22 IS 1 BP 26 EP 36 DI 10.1002/(SICI)1098-2264(199805)22:1<26::AID-GCC4>3.0.CO;2-9 PG 11 WC Oncology; Genetics & Heredity SC Oncology; Genetics & Heredity GA ZK705 UT WOS:000073352900004 PM 9591631 ER PT J AU Valentine, GA Palladino, DM Agosta, E Taddeucci, J Trigila, R AF Valentine, GA Palladino, DM Agosta, E Taddeucci, J Trigila, R TI Volcaniclastic aggradation in a semiarid environment, northwestern Vulcano Island, Italy SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article ID AEOLIAN ARCHIPELAGO; SURGE PROCESSES; TYRRHENIAN SEA; NEW-MEXICO; SEDIMENTATION; EVOLUTION; VOLCANO; TUFFS AB Most studies of volcaniclastic facies and aggradation cycles hale been conducted in regions with humid climates, and on regional scales. Here we document a volcaniclastic succession that formed in a semiarid climate characterized by rare, heavy rains onto a relatively barren volcanic landscape on Vulcano Island, Italy, The deposits, which we informally call the Cuesta succession, occur in a small valley between two rhyolite domes, and consist of a sequence of pyroclastic surge and fallout deposits interbedded with their reworked equiv equivalents, ri phase of eruptive activity characterized by sporadic hydrovolcanic explosions supplied ash to the valley and its flanks. Runoff events during the eruptive phase continually washed ash down to the valley floor in the form of hyperconcentrated flows, The inferred transport mechanism and depositional facies of these beds reflect the control of primary volcanic fragmentation processes on sedimentation; the abundant, medium-to-coarse ash supplied by eruption was incorporated sufficiently easily into the runoff to hyperconcentrate the no rvs, but not sufficiently fine grained to make the no,vs cohesive. These nons moved out onto the floor, merged, and transported ash down the valley axis, depositing the ash as a monotonous succession of massive to faintly laminated beds. The combination of primary deposits and the deposits washed off the valley flanks led to aggradation of the valley floor As eruptions waned, ash was eroded off the flanks faster than it was replenished, lending to a stratigraphic upward increase in lithic clasts derived from the underlying lavas and a wider range of sedimentary facies as the ash load became more variable. After eruptions ceased and all remaining ash was removed from the flanks, aggradation gave way to degradation to form small canyons that expose the succession. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp, Los Alamos, NM 87545 USA. Univ Rome La Sapienza, Dipartimento Sci Terra, I-00185 Rome, Italy. Highline Coll, Des Moines, WA 98198 USA. Univ Rome La Sapienza, Dottorato Ric Sci Terra, I-00185 Rome, Italy. RP Valentine, GA (reprint author), Univ Calif Los Alamos Natl Lab, Geoanal Grp, MS F665, Los Alamos, NM 87545 USA. EM gav@lanl.gov NR 42 TC 7 Z9 7 U1 0 U2 2 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD MAY PY 1998 VL 110 IS 5 BP 630 EP 643 DI 10.1130/0016-7606(1998)110<0630:VAIASE>2.3.CO;2 PG 14 WC Geosciences, Multidisciplinary SC Geology GA ZM146 UT WOS:000073509300006 ER PT J AU Miller, CF Hatcher, RD Harrison, TM Coath, CD Gorisch, EB AF Miller, CF Hatcher, RD Harrison, TM Coath, CD Gorisch, EB TI Cryptic crustal events elucidated through zone imaging and ion microprobe studies of zircon, southern Appalachian Blue Ridge, North Carolina Georgia SO GEOLOGY LA English DT Article ID METAMORPHISM; GRANULITES; COMPLEX AB Compositional zoning reveals multistage growth histories and resorption events in zircon from a high-grade terrane in the eastern Blue Ridge of North Carolina and Georgia These zoning patterns,were used to guide high-resolution ion microprobe dating that places important constraints on the evolution of the southern Appalachian crust. Zircons from granulite facies metapelite have unzoned rims that yield concordant U-Pb ages of 495 +/- 14 Ma. We interpret this as the time of rim growth, which occurred during peak metamorphism early in the protracted orogenic history of the region. Detrital cores, characterized by truncated euhedral zoning, are of Grenville age (1.04-1.26 Ga). Zircons from the Whiteside and Rabun plutons have well-defined, rounded, inherited cores and euhedral, oscillatory-zoned magmatic rims. Rims of Rabun zircons record magmatic crystallization at 374 +/- 4 Ma, whereas Whiteside rims yield a 466 +/- 10 Ma crystallization age. Cores from both plutons include 1.1-1.3 Ga and 2.6-2.7 Ga ages. These data indicate that there,vas no single, voluminous episode of plutonism in this area, that similar material underpinned the region at least from 370 to 470 Ma, and that previously unrecognized Archean basement or Archean basement-derived sedimentary rock was present in the southern Appalachians. Results of this study verify the value of combining zoning and ion microprobe studies: Using conventional U-Pb methods or ion microprobe dating without knowledge of zoning would have made interpreting the events recorded in these zircons and the ages that they yield difficult or impossible. C1 Vanderbilt Univ, Dept Geol, Nashville, TN 37235 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Calif Los Angeles, WM Keck Fdn, Ctr Isotope Geochem, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. Vanderbilt Univ, Dept Geol, Nashville, TN 37235 USA. RP Miller, CF (reprint author), Vanderbilt Univ, Dept Geol, 221 Kirkland Hall, Nashville, TN 37235 USA. RI Harrison, Timothy/E-7443-2012; UCLA, SIMS/A-1459-2011; OI Coath, Christopher/0000-0002-6520-2223 NR 25 TC 29 Z9 30 U1 1 U2 2 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0091-7613 J9 GEOLOGY JI Geology PD MAY PY 1998 VL 26 IS 5 BP 419 EP 422 DI 10.1130/0091-7613(1998)026<0419:CCEETZ>2.3.CO;2 PG 4 WC Geology SC Geology GA ZM147 UT WOS:000073509400009 ER PT J AU Caldeira, K Berner, RA AF Caldeira, K Berner, RA TI The need for mass balance and feedback in the geochemical carbon cycle: Reply SO GEOLOGY LA English DT Article ID CO2; METAMORPHISM C1 Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, Livermore, CA 94550 USA. Yale Univ, Dept Geol & Geophys, New Haven, CT 06511 USA. RP Caldeira, K (reprint author), Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, POB 5508, Livermore, CA 94550 USA. RI Caldeira, Ken/E-7914-2011 NR 10 TC 0 Z9 0 U1 0 U2 8 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0091-7613 J9 GEOLOGY JI Geology PD MAY PY 1998 VL 26 IS 5 BP 478 EP 478 PG 1 WC Geology SC Geology GA ZM147 UT WOS:000073509400028 ER PT J AU Bosl, WJ Dvorkin, J Nur, A AF Bosl, WJ Dvorkin, J Nur, A TI A study of porosity and permeability using a lattice Boltzmann simulation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EQUATION; MODELS AB We explicitly calculate the absolute (single-phase) permeability of simulated granular rocks as the pore space is evolved by various diagenetic schemes. Our goal is to match our computed curves to laboratory measurements of porosity-permeability relationships in real rocks. To achieve this goal we model rock as a dense random pack of identical spherical grains with diagenetic cement deposited in the pore space. The positions of the sphere centers in our numerical model are taken from experimental measurements (the Finney pack). The diagenesis is simulated in various ways: uniform cement deposition on the surface of each grain (uniform growth of the grains); cement deposition at grain contacts; cement deposition away from grain contacts; random filling of the pore spaces; and various combinations of these. Permeability is computed by explicitly modeling Stokes flow in the simulated pore space using a lattice Boltzmann method. Our simulations produce distinctively different porosity-permeability relationships which are characteristic of the cement deposition pattern. The distinctive porosity-permeability relationships found in laboratory measurements of real rocks are matched by certain simulation schemes. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. RP Bosl, WJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, POB 808,L-561, Livermore, CA 94550 USA. NR 8 TC 45 Z9 45 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1475 EP 1478 DI 10.1029/98GL00859 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900048 ER PT J AU Cartwright, DC Brunger, MJ Campbell, L Mojarrabi, B Teubner, PJO AF Cartwright, DC Brunger, MJ Campbell, L Mojarrabi, B Teubner, PJO TI Electron impact excitation of nitric oxide under auroral conditions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VIBRATIONAL POPULATIONS; LOWER THERMOSPHERE; INFRARED-EMISSION; CROSS-SECTIONS; NO; X(2)PI; STATE AB Excitation of the ground vibrational levels and nine excited electronic states in NO has been simulated for an IBC II aurora. New electron impact excitation cross sections for NO were combined with a measured IBC II auroral secondary electron energy distribution and the electronic-vibrational populations were determined for conditions of statistical equilibrium. This model predicts an extended vibrational distribution in the NO ground electronic state produced by radiative cascade from the many higher lying doublet excited electronic states. In addition to energy storage in the vibrational population of the ground electronic state, both the a (4) Pi and L' (2) Phi excited electronic states are predicted to have relatively high number densities in aurora. This extended ground state vibrational distribution is predicted to emit infrared [IR] radiation from 1.3 to 8.2 mu m and most IR bands are predicted to be stronger than band emission from any of the electonic transitions. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Flinders Univ S Australia, Dept Phys, Adelaide, SA 5001, Australia. RP Cartwright, DC (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 22 TC 12 Z9 12 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1495 EP 1498 DI 10.1029/98GL01025 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900053 ER PT J AU Riley, P Gosling, JT AF Riley, P Gosling, JT TI Do coronal mass ejections implode in the solar wind? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Ulysses observations show that many coronal mass ejections observed at high heliographic latitudes expand because they initially have higher internal pressures than that of the surrounding solar wind. This expansion commonly drives a shock wave into the ambient-wind in all directions. In the analogous process of an explosion in the Earth's atmosphere, the expansion is followed by an implosion at the center of the disturbance. Ulysses observations to date, however, suggest that these "overexpanding" CMEs do not implode, at least within 5.4 AU, in spite of the fact that many have central pressures at large heliocentric distances that are considerably lower than that of the surrounding solar wind. We use fluid simulations to investigate whether these CMEs might eventually collapse at larger heliocentric distances. We find that for a wide range of initial perturbations close to the Sun the CMEs do not implode at any heliocentric distance. Implosion does not occur because of the overall reduction in pressure associated with the spherical expansion of the solar wind. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Riley, P (reprint author), SciberNet Inc, 5414 Oberlin Dr,Suite 251, San Diego, CA 92121 USA. NR 11 TC 28 Z9 28 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1529 EP 1532 DI 10.1029/98GL01057 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900062 ER PT J AU Constable, SC Orange, AS Hoversten, GM Morrison, HF AF Constable, SC Orange, AS Hoversten, GM Morrison, HF TI Marine magnetotellurics for petroleum exploration Part I: A sea-floor equipment system SO GEOPHYSICS LA English DT Article ID ELECTROMAGNETIC INDUCTION; OCEANIC-CRUST; INVERSION; NOISE AB Induction in electrically conductive seawater attenuates the magnetotelluric (MT) fields and, coupled with a minimum around 1 Hz in the natural magnetic field spectrum, leads to a dramatic loss of electric and magnetic field power on the sea floor at periods shorter than 1000 s, For this reason the marine MT method traditionally has been used only at periods of 10(3) to 10(5) s to probe deep mantle structure; rarely does a sea-floor MT response extend to a 100-s period. To be useful for mapping continental shelf structure at depths relevant to petroleum exploration, however, MT measurements need to be made at periods between 1 and 1000 s. This can be accomplished using ac-coupled sensors, induction coils for the magnetic field, and an electric field amplifier developed for marine controlled-source applications. The electrically quiet sea floor allows the attenuated electric field to be amplified greatly before recording; in deep (l-km) water, motional noise in magnetic field sensors appears not to be a problem. In shallower water, motional noise does degrade the magnetic measurement, but sea-floor magnetic records can be replaced by land recordings, producing an effective sea-surface MT response. Field trials of such equipment in l-km-deep water produced good-quality MT responses at periods of 3 to 1000 s: in shallower water, responses to a few hertz can be obtained. Using an autonomous sea-floor data logger developed at Scripps Institution of Oceanography, marine surveys of 50 to 100 sites are feasible. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Arnold Orange Associates, Austin, TX 78759 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94270 USA. RP Univ Calif San Diego, Scripps Inst Oceanog, IGPP 0225,8604 La Jolla Shores Dr, La Jolla, CA 92093 USA. EM sconstable@ucsd.edu; 73321.3045@compuserve.com; mhovers@socrates.berkeley.edu; hfmengeo@socrates.berkeley.edu RI Constable, Steven/B-8959-2008 NR 25 TC 81 Z9 91 U1 0 U2 14 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 EI 1942-2156 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 1998 VL 63 IS 3 BP 816 EP 825 DI 10.1190/1.1444393 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZP843 UT WOS:000073794000004 ER PT J AU Hoversten, GM Morrison, HF Constable, SC AF Hoversten, GM Morrison, HF Constable, SC TI Marine magnetotellurics for petroleum exploration, Part II: Numerical analysis of subsalt resolution SO GEOPHYSICS LA English DT Article ID TRANSVERSELY ISOTROPIC MEDIA; MIGRATION ERROR; INVERSION AB In areas where seismic imaging of the base of salt structures is difficult, seaborne electromagnetic techniques offer complementary as well as independent structural information. Numerical models of 2-D and 3-D salt structures demonstrate the capability of the marine magnetotelluric (MT) technique to map the base of the salt structures with an average depth accuracy of better than 10%. The mapping of the base of the salt with marine MT is virtually unaffected by internal variation within the salt. Three-dimensional anticlinal structures with a horizontal aspect ratio greater than two can be interpreted adequately via two-dimensional inversions. Marine MT can distinguish between salt structures which possess deep vertical roots and those which do not. One measure of the relative accuracy of MT acid seismic methods can be made by considering the vertical and lateral position errors in the locations of interfaces caused by neglecting velocity anisotropy in migration. For the shallow part of the section where two-way travel times are on the order of 1 s, the vertical and lateral position errors in the locations of salt-sediment interfaces from 2-D MT inversion is more than twice the expected migration error in reflectors in transversely isotropic sediments, such as those in the Gulf of Mexico. Deeper in the section where two-way times are on the order of 4 s, lateral position errors in migration become comparable to those of the MT inverse, whereas seismic vertical position errors remain more than a factor of two smaller than MT errors. This analysis shows that structural mapping accuracy would be improved using MT and seismic together. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM mhovers@socrates.berkeley.edu; hfmengeo@socrates.berkeley.edu; constable@ucsd.edu RI Constable, Steven/B-8959-2008 NR 20 TC 35 Z9 39 U1 0 U2 6 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 EI 1942-2156 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 1998 VL 63 IS 3 BP 826 EP 840 DI 10.1190/1.1444394 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZP843 UT WOS:000073794000005 ER PT J AU Vasco, DW Peterson, JE Majer, EL AF Vasco, DW Peterson, JE Majer, EL TI Resolving seismic anisotropy: Sparse matrix methods for geophysical inverse problems SO GEOPHYSICS LA English DT Article ID TRAVEL-TIME TOMOGRAPHY; CONJUGATE-GRADIENT; MEDIA; RESOLUTION AB Two techniques for the singular value decomposition (SVD) of large sparse matrices are directly applicable to geophysical inverse problems: subspace iteration and the Lanczos method. Both methods require very little in-core storage and efficiently compute a set of singular values and singular vectors. A comparison of the singular value and vector estimates of these iterative approaches with the results of a conventional in-core SVD algorithm demonstrates their accuracy. Hence, it is possible to conduct an assessment of inversion results for larger sparse inverse problems such as those arising in seismic tomography. As an example, we examine the resolution matrix associated with a crosswell seismic inversion of first arrival times for lateral variations in anisotropy. The application to a set of first arrival times from a crosswell survey at the Grimsel Laboratory emphasizes the utility of including anisotropy in a traveltime inversion. The isotropic component of the estimated velocity structure appears to be well constrained even when anisotropy is included in the inversion. In the case of the Grimsel experiment, we are able to resolve a fracture zone, in agreement with borehole fracture intersections. Elements of the resolution matrix reveal moderate averaging among anisotropy coefficients as well as between anisotropy coefficients and source-receiver static terms. The information on anisotropy, such as the directions of maximum velocity, appears sensitive to lateral variations in velocity and must be interpreted with some caution. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Vasco, DW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Bldg 90,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM dwvasco@lbl.gov; barstow@ccs.lbl.gov; elmajer@lbl.gov RI Vasco, Donald/I-3167-2016 OI Vasco, Donald/0000-0003-1210-8628 NR 37 TC 12 Z9 12 U1 0 U2 0 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 1998 VL 63 IS 3 BP 970 EP 983 DI 10.1190/1.1444408 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZP843 UT WOS:000073794000019 ER PT J AU Faure, H Adams, JM Faure-Denard, L AF Faure, H Adams, JM Faure-Denard, L TI Quaternary carbon cycle changes: Introduction to future studies SO GLOBAL AND PLANETARY CHANGE LA English DT Editorial Material C1 Fac Sci Luminy, LGQ, CNRS, F-13288 Marseille 09, France. Fac Sci Luminy, Ctr Oceanol Marseille, F-13288 Marseille, France. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. CEREGE, CNRS, LGQ, F-13545 Aix En Provence 04, France. RP Faure, H (reprint author), Fac Sci Luminy, LGQ, CNRS, Case 901, F-13288 Marseille 09, France. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD MAY PY 1998 VL 17 BP 1 EP 2 PG 2 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA ZY040 UT WOS:000074580600001 ER PT J AU Adams, JM Faure, H AF Adams, JM Faure, H TI A new estimate of changing carbon storage on land since the last glacial maximum, based on global land ecosystem reconstruction SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT 15 INQUA Symposium on Carbon Cycle CY AUG, 1995 CL BERLIN, GERMANY SP INQUA Commiss Carbon, IGCP 404, INTAS DE ecosystem; Last Glacial Maximum; carbon reservoir ID TERRESTRIAL BIOSPHERE; ATMOSPHERIC CO2; CLIMATE; BP; VEGETATION; RESPONSES; DYNAMICS; CYCLE AB A review of global land vegetation 18,000, 8000, and 5000 C-14 years B.P. allowed map reconstructions of past ecosystem distribution. By collecting soil and vegetation carbon storage data from the ecological literature, the map reconstructions were then used to estimate the total organic carbon storage on land at each of these time slices. Our best estimate suggests that there was an extremely large increase in land organic carbon storage, of around 1500 Gt (with extreme outer error limits for the increase placed at around 900 and 1900 Gt, respectively) between the Last Glacial Maximum (LGM) and the early-to-mid Holocene. It seems that the world's terrestrial carbon reservoirs more than doubled in size between full-glacial and full-interglacial conditions, due to a great increase in the areas of forest and other carbon-rich ecosystems. Although there are many uncertainties in such calculations, comparing them to methods used in other published estimates, we suggest that the present estimate may represent an overall improvement in accuracy. Apparent problems in previous studies include the use of relatively few data points and a limited range of types of palaeoenvironmental evidence, the unselective use of carbon storage data from anthropogenically modified ecosystems, and the assignment of an anomalously high carbon storage to the LGM 'steppe-tundra' ecosystem. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Fac Sci Luminy, Ctr Oceanol Marseille, F-13288 Marseille 09, France. Fac Sci Luminy, LGQ, CNRS, F-13288 Marseille 09, France. RP Adams, JM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, MS 6335,Bldg 1000, Oak Ridge, TN 37831 USA. EM jonathan@elvis.esd.ornl.gov; faure@luminy.univ-mrs.fr NR 68 TC 31 Z9 31 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD MAY PY 1998 VL 17 BP 3 EP 24 PG 22 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA ZY040 UT WOS:000074580600002 ER PT J AU Lioubimtseva, E Simon, B Faure, H Faure-Denard, L Adams, JM AF Lioubimtseva, E Simon, B Faure, H Faure-Denard, L Adams, JM TI Impacts of climatic change on carbon storage in the Sahara-Gobi desert belt since the Last Glacial Maximum SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT 15 INQUA Symposium on Carbon Cycle CY AUG, 1995 CL BERLIN, GERMANY SP INQUA Commiss Carbon, IGCP 404, INTAS DE Sahara-Gobi desert belt; carbon storage; Last Glacial Maximum ID AFRICA AB Reconstructions of palaeolandscapes for intervals with different climatic conditions help define regional trends in palaeobiomass and carbon storage due to global climatic change. The Sahara-Gobi desert belt stretches for about 15,000 km from the Atlantic coast to Northern China. Natural vegetation zones have undergone a number of significant shifts and complex qualitative changes under the contrasting climatic conditions of the Last Glacial Maximum (LGM) and the Holocene Climatic Optimum (HCO). The results presented here are based on palynological, pedological and sedimentological evidence, which indicate that the amount of carbon stored in vegetation and soils would have been much smaller during the Glacial Maximum than in the interglacial and post glacial times. Comparison of a set of palaeogeographic maps of this region for the chosen time-slices (ca. 20-18 ka, 9-8 ka and the present) allows us to discuss land biomass changes. Dry and cool conditions during the LGM resulted in the spread of arid and semi-arid ecosystems at northern and southern margins of the desert belt. The southern limit of the Sahara migrated southward at least 400 km relative to its present position, and almost 1000 km south compared to the mid-Holocene. The northern margin of the temperate deserts and dry steppes of Central Asia shifted northward for not less than 200-300 km over Kazakhstan, southern Siberia and Mongolia, In this study we have quantified variations of the main ecosystems from the LGM to the HCO in terms of changes in carbon storage. Each vegetation zone has been assigned a carbon density for living and dead (soil) organic matter. During the last world deglaciation, the Sahara-Gobi desert belt was a sink for approximately 200 Gt of atmospheric carbon, but since the mid-Holocene, it has been a source of carbon. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Moscow MV Lomonosov State Univ, Dept Phys Geog, Moscow 119899, Russia. CEREGE, CNRS, STSI, F-13545 Aix En Provence, France. Univ Aix Marseille 2, COM, F-13288 Marseille 9, France. CEREGE, CNRS, LGQ, F-13545 Aix En Provence, France. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Lioubimtseva, E (reprint author), Moscow MV Lomonosov State Univ, Dept Phys Geog, Moscow 119899, Russia. EM wludwig@illite.u-strasbg.fr NR 39 TC 16 Z9 16 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD MAY PY 1998 VL 17 BP 95 EP 105 DI 10.1016/S0921-8181(98)00015-0 PG 11 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA ZY040 UT WOS:000074580600008 ER PT J AU Toran, L Bryant, S Saunders, J Wheeler, MF AF Toran, L Bryant, S Saunders, J Wheeler, MF TI A two-tiered approach to reactive transport: Application to Sr mobility under variable pH SO GROUND WATER LA English DT Article ID RADIONUCLIDE; COMPONENTS; MIGRATION; SORPTION; MODELS; SOILS AB One benefit of a coupled geochemistry/transport approach is that interactions between chemical constituents that can change the mobility of species (such as pH) can be treated explicitly, rather than lumping all of the geochemistry into a single term (i.e., the retardation factor). A two-tiered approach to modeling coupled geochemistry/transport is presented here, which allows a comparison of the results of different methods as well as better efficiency in modeling time, The codes ParSSim, a coupled transport code for supercomputers, and PHREEQC, an advective geochemistry code, were used to model Sr mobility under varying pH, The problem was based on liquid low level radioactive waste that was disposed at Oak Ridge National Laboratory (Oak Ridge, Tennessee) in a highly alkaline solution to try to enhance precipitation and sorption, Interactions with carbonate rock and ground water lowered the pH and led to mobilization of radionuclides such as Sr-90. Simulation of contaminant migration in this mixing environment requires a coupled geochemistry and transport model. The interplay between propagation of a pH front (which was retarded) and propagation of the Sr front leads to a fast-moving pulse of Sr as well as a strongly retarded front of Sr. This behavior could not have been predicted by a geochemistry or a transport code alone. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Texas, Texas Inst Comp & Appl Math, Austin, TX 78712 USA. Auburn Univ, Dept Geol, Auburn, AL 36849 USA. RP Toran, L (reprint author), Temple Univ, Dept Geol, Philadelphia, PA 19122 USA. NR 19 TC 14 Z9 14 U1 0 U2 6 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD MAY-JUN PY 1998 VL 36 IS 3 BP 404 EP 408 DI 10.1111/j.1745-6584.1998.tb02810.x PG 5 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA ZM547 UT WOS:000073551100007 ER PT J AU Kaneta, T Jeong, H Yeung, ES AF Kaneta, T Jeong, H Yeung, ES TI Miniaturized injection method using silver-coated capillaries in DNA sequencing by multiplexed capillary electrophoresis SO HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY LA English DT Article DE DNA; capillary electrophoresis; sample injection ID ARRAY ELECTROPHORESIS; FRAGMENTS AB Silver-coated capillaries were used for direct sample injection in multiplexed capillary electrophoresis. The absence of an additional electrode simplifies mechanical alignment, reduces contamination, and decreases the amount of sample needed. Capillaries were coated by a silver paint which is a suspension of silver particles in an organic solvent. To provide electrical contact, the upper part of the capillary and a platinum wire were wound together by a copper wire. Electrical resistance from the platinum wire to the tip of the capillary was small enough (7 Omega to 50 Omega) to inject large amounts of DNA samples. Electrokinetic injection from eight separate sample vials to eight capillaries was demonstrated for DNA sequencing by multiplexed capillary electrophoresis. Signal-to-noise ratio and resolution were good enough to call up to 350 base pairs. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Kyushu Univ, Grad Sch Engn, Dept Chem Syst & Engn, Funct Mat Chem Grp, Fukuoka 81281, Japan. Sookmyung Womens Univ, Dept Chem, Seoul 140742, South Korea. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI Kaneta, Takashi/D-3593-2011 NR 10 TC 3 Z9 3 U1 0 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0935-6304 J9 HRC-J HIGH RES CHROM JI HRC-J. High Resolut. Chromatogr. PD MAY PY 1998 VL 21 IS 5 BP 287 EP 290 PG 4 WC Chemistry, Analytical SC Chemistry GA ZT726 UT WOS:000074118800004 ER PT J AU Chow, WW Crawford, MH Girndt, A Koch, SW AF Chow, WW Crawford, MH Girndt, A Koch, SW TI Threshold conditions for an ultraviolet wavelength GaN quantum-well laser SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE laser theory; many-body effects; nitride materials/devices; quantum-well lasers; semiconductor device modeling; semiconductor lasers ID OPTICAL GAIN; ALN; SEMICONDUCTORS; SPECTRA; EDGE AB This paper describes an analysis of the threshold conditions for a GaN-AlGaN strained quantum-well (QW) laser. Gain spectra are computed using a many-body microscopic laser theory. The spontaneous emission rates are extracted from the gain spectra using a phenomenological expression based on energy conservation arguments. From the gain and spontaneous emission spectra, threshold current densities are estimated. Inhomogeneous broadening due to spatial variations in QW thickness are included in the analysis. Gain-current characteristics are determined for a number of laser heterostructure designs where the GaN QW width and Al composition of the AlGaN barrier material are varied. C1 Sandia Natl Labs, Albuquerque, NM USA. Univ Marburg, Dept Phys, D-35032 Marburg, Germany. Univ Marburg, Ctr Mat Sci, D-35032 Marburg, Germany. RP Chow, WW (reprint author), Sandia Natl Labs, Albuquerque, NM USA. NR 26 TC 8 Z9 8 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 1998 VL 4 IS 3 BP 514 EP 519 DI 10.1109/2944.704111 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 103MC UT WOS:000075158800007 ER PT J AU Lee, J Cho, H Hays, DC Abernathy, CR Pearton, SJ Shul, RJ Vawter, GA Han, J AF Lee, J Cho, H Hays, DC Abernathy, CR Pearton, SJ Shul, RJ Vawter, GA Han, J TI Dry etching of GaN and related materials: Comparison of techniques SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE dry etching; GaN; laser diodes ID INP; TEMPERATURE; CHLORINE; NITRIDE; CL-2/AR; ALN AB The etch rates and feature anisotropy for GaN, AlN, and InN etched in Cl-2-Ar plasmas with four different techniques were examined, Conventional reactive ion etching produces the slowest etch rates, even when high de self-biases (>-900 V) are employed, and this leads to mask erosion and sloped feature sidewalls during ridge waveguide fabrication. Two high-ion-density techniques, inductively coupled plasma and electron cyclotron resonance, provide the highest etch rates and most anisotropic features through their combination of high-ion flux and moderate-ion energy. Etch selectivities of GaN to AlN and InN are typically less than or equal to 4 in these tools. Reactive ion beam etching utilizing a high density (ICP) source is also an attractive option for pattern transfer in the nitrides, although its etch rates are slower than for ICP or ECR due to its lower operating pressure. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Lee, J (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 21 TC 30 Z9 30 U1 2 U2 20 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 1998 VL 4 IS 3 BP 557 EP 563 DI 10.1109/2944.704117 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 103MC UT WOS:000075158800013 ER PT J AU Simmons, GJ AF Simmons, GJ TI The history of subliminal channels (Reprinted from Proc 1st Int Workshop on Information Hiding, pg 237-256, May 30 June 1, 1996) SO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS LA English DT Reprint DE communication system security; cryptography; data security; nuclear weapons; protocols; steganography; subliminal channels; treaty verification AB In 1978 the United States was considering adopting a national security protocol designed to enable the U.S.S.R. to verify how many Minuteman missiles the United States had emplaced in a field of 1000 silos without revealing which sides actually contained missiles. For this protocol to have been acceptable to the U.S.S.R., the messages would have had to be digitally signed with signatures which the U.S.S.R. could verify were authentic, but which the United States could not forge. Subliminal channels were the discovery that these digital signatures could host undetectable covert channels. In general, any time redundant information is introduced into a communication to provide an overt function such as digital signatures, error detection and/or correction, authentication, etc. it may be possible to subvert the purported function to create a covert (subliminal) communications channel, This paper recounts the development of subliminal channels from their origins when only a couple of bits could be communicated covertly to today when potentially a couple of hundred bits can be concealed ire signatures generated using the most popular digital signature schemes. C1 Sandia Natl Labs, Albuquerque, NM 87106 USA. RP Simmons, GJ (reprint author), POB 365, Sandia Pk, NM 87047 USA. NR 4 TC 23 Z9 27 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0733-8716 J9 IEEE J SEL AREA COMM JI IEEE J. Sel. Areas Commun. PD MAY PY 1998 VL 16 IS 4 BP 452 EP 462 DI 10.1109/49.668969 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA ZL242 UT WOS:000073413000002 ER PT J AU Simmons, GJ AF Simmons, GJ TI Results concerning the bandwidth of subliminal channels SO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS LA English DT Article; Proceedings Paper CT RSA Data Security Conference CY JAN 28-31, 1997 CL SAN FRANCISCO, CALIFORNIA DE communication system security; cryptography; data security; game theory; information rates; protocols AB In conjunction with a six-month research program on Computer Security, Cryptology and Coding Theory hosted by the Isaac Newton Institute of Mathematical Sciences, University of Cambridge, Cambridge, U.K., a Workshop on Information Hiding was held from May 30 through June 1, 1996. This workshop was devoted to all aspects of information hiding-other than the usual cryptographic concealment of content, including steganography, subliminal channels, fingerprinting, covert channels, etc. Two surprising results pertaining to subliminal channels were presented or grew out of presentations made at this workshop. One is of interest to the secure communications protocol designer concerned with denying the use of subliminal channels, while the other is important to the designer, or user, of subliminal channels. The first raises the question of whether the notion of a "subliminal-free" communication channel is an oxymoron, i.e., is it possible to force the bandwidth of the subliminal channel to be truly zero? The second forces a more precise formulation of a conjecture the author had made that the bandwidth of a subliminal channel is logarithmically limited if the transmitter is unwilling to trust the subliminal receiver unconditionally. Motivated by these results, this paper reexamines the fundamental questions of the bandwidth available for subliminal communication as a function of the trust the transmitter has in the subliminal receiver and of a logically sound interpretation of the term "subliminal-free." C1 Sandia Natl Labs, Albuquerque, NM 87106 USA. RP Simmons, GJ (reprint author), POB 365, Sandia Pk, NM 87047 USA. NR 13 TC 18 Z9 22 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0733-8716 J9 IEEE J SEL AREA COMM JI IEEE J. Sel. Areas Commun. PD MAY PY 1998 VL 16 IS 4 BP 463 EP 473 DI 10.1109/49.668970 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA ZL242 UT WOS:000073413000003 ER PT J AU Luong, SQ Ortiz, GG Zhou, Y Lu, J Hains, CP Cheng, JL Hou, HQ Vawter, GA AF Luong, SQ Ortiz, GG Zhou, Y Lu, J Hains, CP Cheng, JL Hou, HQ Vawter, GA TI Monolithic wavelength-graded VCSEL and resonance-enhanced photodetector arrays for parallel optical interconnects SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE integrated optoelectronics; semiconductor laser arrays; optical array; optical communication; optical interconnections; optoelectronic devices; photodetectors; wavelength-division multiplexing ID SURFACE-EMITTING LASERS; EPITAXY; GROWTH AB Monolithic arrays of wavelength-graded vertical-cavity surface-emitting lasers (VCSEL's) and resonance-enhanced photodetectors (PD's) have been realized with the same epilayer structure using the topography-controlled enhancement and reduction of the metal-organic chemical vapor deposition (MOCVD) growth rate on a patterned substrate. The repeatability of this technique was demonstrated by using different VCSEL and resonance-enhanced photodetector (REPD) arrays from the same wafer. C1 Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Luong, SQ (reprint author), Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. NR 7 TC 18 Z9 18 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAY PY 1998 VL 10 IS 5 BP 642 EP 644 DI 10.1109/68.669222 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA ZH777 UT WOS:000073146600004 ER PT J AU Cresswell, MW Allen, RA Guthrie, WF Sniegowski, JJ Ghoshtagore, RN Linholm, LW AF Cresswell, MW Allen, RA Guthrie, WF Sniegowski, JJ Ghoshtagore, RN Linholm, LW TI Electrical linewidth test structures fabricated in monocrystalline films for reference-material applications SO IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING LA English DT Article; Proceedings Paper CT 1997 IEEE International Conference on Microelectronic Test Structures CY MAR 17-20, 1997 CL MONTEREY, CALIFORNIA SP IEEE Electron Devices Soc AB The physical widths of reference features incorporated into electrical linewidth test structures patterned in films of monocrystalline silicon have been determined from Kelvin voltage measurements. The films in which the test structures are patterned are electrically insulated from the bulk-silicon substrate by a layer of silicon dioxide provided by SIMOX (Separation by the IR IMplantation of OXygen) processing. The motivation is to facilitate the development of linewidth reference materials for critical-dimension (CD) metrology-instrument calibration. The selection of the (110) orientation of the starting silicon and the orientation of the structures' features relative to the crystal lattice enable a lattice-plane-selective etch to generate reference-feature proper ties of rectangular cross section and atomically planar sidewalls. These properties are highly desirable for CD applications in which feature widths are certified with nanometer-level uncertainty for use by a diverse range of CD instruments. End applications include the development and calibration of new generations of CD instruments directed at controlling processes for manufacturing devices having sub-quarter-micrometer features. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. Sandia Natl Labs, Microelect Dev Labs, Albuquerque, NM 87185 USA. RP Cresswell, MW (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. EM michael.cresswell@nist.gov NR 15 TC 3 Z9 3 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0894-6507 J9 IEEE T SEMICONDUCT M JI IEEE Trans. Semicond. Manuf. PD MAY PY 1998 VL 11 IS 2 BP 182 EP 193 DI 10.1109/66.670152 PG 12 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZM114 UT WOS:000073506100002 ER PT J AU Polikar, R Udpa, L Udpa, SS Taylor, T AF Polikar, R Udpa, L Udpa, SS Taylor, T TI Frequency invariant classification of ultrasonic weld inspection signals SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID TIME AB Automated signal classification systems are finding increasing use in many applications for the analysis and interpretation of large volumes of signals. Such systems show consistency of response and help reduce the effect of variabilities associated with human interpretation. This paper deals with the analysis of ultrasonic NDE signals obtained during weld inspection of piping in boiling water reactors. The overall approach consists of three major steps, namely, frequency invariance, multiresolution analysis, and neural network classification. The data are first preprocessed whereby signals obtained using different transducer center frequencies are transformed to an equivalent reference frequency signal. Discriminatory features are then extracted using a multiresolution analysis technique, namely, the discrete wavelet transform (DWT). The compact feature vector obtained using wavelet analysis is classified using a multilayer perceptron neural network. Two different databases containing weld inspection signals have been used to test the performance of the neural network. Initial results obtained using this approach demonstrate the effectiveness of the frequency invariance processing technique and the DWT analysis method employed for feature extraction. C1 Iowa State Univ Sci & Technol, Dept Elect & Comp Engn, Ames, IA 50011 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Polikar, R (reprint author), Iowa State Univ Sci & Technol, Dept Elect & Comp Engn, Ames, IA 50011 USA. RI Polikar, Robi/N-4742-2015 OI Polikar, Robi/0000-0002-2739-4228 NR 17 TC 60 Z9 61 U1 0 U2 15 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 1998 VL 45 IS 3 BP 614 EP 625 DI 10.1109/58.677606 PG 12 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA ZQ882 UT WOS:000073912500010 PM 18244213 ER PT J AU Wu, JZ Prausnitz, JM AF Wu, JZ Prausnitz, JM TI Phase equilibria for systems containing hydrocarbons, water, and salt: An extended Peng-Robinson equation of state SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID AQUEOUS SODIUM-CHLORIDE; THERMODYNAMIC PROPERTIES; ELECTROLYTE-SOLUTIONS; MODEL AB The empirical success of the Peng-Robinson equation of state (PREOS) is unmatched; there is no other simple equation of state of the van der Waals form that has shown such wide and reliable applicability to the calculation of vapor-liquid equilibria (VLE) for systems containing light hydrocarbons, permanent gases, carbon dioxide, and hydrogen sulfide. PREOS is one of the great success stories of applied chemical engineering thermodynamics. However, PREOS also has Limitations; two of these are addressed here. Theoretically based extensions are presented, first, for including water and aqueous hydrocarbon mixtures and, second, for including salt in water and in aqueous hydrocarbon mixtures. Illustrative examples show that these extensions are successful for VLE (where L refers to a hydrocarbon liquid dilute in water) and for VLE (where L refers to saline water). Because the extension to include water, based on SAFT (statistical association fluid theory), cannot properly take into account the well-documented hydrophobic effect, it is not yet possible to give a good representation of phase equilibria when one of the phases is a dilute aqueous liquid solution of hydrocarbon where the hydrophobic effect is significant. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Wu, Jianzhong/I-5164-2013; OI Wu, Jianzhong/0000-0002-4582-5941 NR 22 TC 81 Z9 84 U1 3 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 1998 VL 37 IS 5 BP 1634 EP 1643 DI 10.1021/ie9706370 PG 10 WC Engineering, Chemical SC Engineering GA ZM065 UT WOS:000073501200009 ER PT J AU Croiset, E Rice, SF AF Croiset, E Rice, SF TI Direct observation of H2O2 during alcohol oxidation by O-2 in supercritical water SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID RAMAN-SPECTROSCOPIC MEASUREMENT; METHANOL; CONVERSION; KINETICS AB This paper presents the direct quantitative measurement of the presence of hydrogen peroxide as an intermediate produced during the oxidation of methanol, ethanol, and 1-propanol by oxygen in supercritical water. The concentration of H2O2 is measured as a function of reaction time in an optically accessible, high-pressure flow reactor by monitoring the intensity of a strong resonance in the Raman spectrum at 874 cm(-1) that is characteristic of the O-O vibrational stretch. Transient concentrations of H2O2 as high as 0.0065 mol/L (0.1% mole fraction) are measured during the oxidation of ethanol at feed mole fractions of 0.4% at 430 degrees C and 24.5 MPa. Significantly lower transient concentrations of H2O2 are observed during methanol oxidation. The experimentally observed transient H2O2 concentration during methanol oxidation is compared to that predicted by two similar elementary reaction mechanisms and found to be distinctly lower than the models predict. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Rice, SF (reprint author), Sandia Natl Labs, Combust Res Facil, MS9052,POB 969, Livermore, CA 94551 USA. OI Croiset, Eric/0000-0002-6923-5751 NR 10 TC 22 Z9 22 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 1998 VL 37 IS 5 BP 1755 EP 1760 DI 10.1021/ie970711e PG 6 WC Engineering, Chemical SC Engineering GA ZM065 UT WOS:000073501200025 ER PT J AU Edwards, DM Shachter, RD Owens, DK AF Edwards, DM Shachter, RD Owens, DK TI A dynamic HIV-transmission model for evaluating the costs and benefits of vaccine programs SO INTERFACES LA English DT Article DE health care; epidemiology; dynamic programming; models ID HUMAN-IMMUNODEFICIENCY-VIRUS; RECOMBINANT GP160; CHILDBEARING AGE; SCREENING WOMEN; SAN-FRANCISCO; AIDS VACCINES; IMMUNOGENICITY; INFECTION; SAFETY; IMMUNITY AB We developed a dynamic model of HIV transmission to evaluate the costs and benefits of HIV-vaccine programs in a population of homosexual men. We examined how changes in highrisk sexual behavior and the growth pattern of the epidemic influence the cost-effectiveness of preventive vaccines and of therapeutic vaccines. We found that the effect of reductions in condom use is more important for therapeutic vaccines than for preventive vaccines. Therapeutic vaccines may increase HIV seroprevalence in the population, unless the vaccine program is accompanied by increased condom use. Epidemic growth patterns also influence the cost-effectiveness of both vaccines, but the effects are more pronounced for preventive vaccines, which are more cost-effective in an early-stage epidemic than in a late-stage epidemic. C1 Sandia Natl Labs, Syst Res Dept MS9201, Livermore, CA 94551 USA. Stanford Univ, Dept Engn Econ Syst & Operat Res, Stanford, CA 94305 USA. Vet Adm Palo Alto Hlth Care Syst, Palo Alto, CA 94304 USA. Stanford Univ, Dept Med, Stanford, CA 94305 USA. RP Edwards, DM (reprint author), Sandia Natl Labs, Syst Res Dept MS9201, POB 969, Livermore, CA 94551 USA. NR 45 TC 21 Z9 21 U1 0 U2 1 PU INST OPERATIONS RESEARCH MANAGEMENT SCIENCES PI LINTHICUM HTS PA 901 ELKRIDGE LANDING RD, STE 400, LINTHICUM HTS, MD 21090-2909 USA SN 0092-2102 J9 INTERFACES JI Interfaces PD MAY-JUN PY 1998 VL 28 IS 3 BP 144 EP 166 DI 10.1287/inte.28.3.144 PG 23 WC Management; Operations Research & Management Science SC Business & Economics; Operations Research & Management Science GA 109HN UT WOS:000075316200010 ER PT J AU Baker, I Li, X Xiao, H Carleton, R George, EP AF Baker, I Li, X Xiao, H Carleton, R George, EP TI The room temperature strengthening effect of boron as a function of aluminum concentration in FeAl SO INTERMETALLICS LA English DT Article DE iron alumides (based on FeAl); mechanical properties at ambient temperatures; casting; extrusion; defects, constitutional vacancies; mechanical testing ID YIELD STRENGTH; DOPED FEAL; GRAIN-SIZE; PERCENT AL; BEHAVIOR; SENSITIVITY; FE-45AL; ALLOYS AB Measurements of the effects of boron on the yield strength, lattice parameter, vacancy concentration and anti-site atom concentration of FeAl as a function of aluminum concentration have been performed and the results compared with data for similar but undoped FeAl. It has been shown that boron does not affect the degree of order, vacancy concentration or anti-site atom concentration in FeAl. Boron produces an increase in lattice parameter in FeAl but both this increase and the lattice strain per atomic percent boron decrease with increasing aluminum concentration. The effect of boron on the strength of FeAl depends on whether vacancies are present. For FeAl containing few vacancies (less than or equal to 45 at %Al) the strength increase per atomic percent boron increases with increasing aluminum concentration; when vacancies are present (greater than or equal to 48 at %Al), boron strengthening shows little change with aluminum concentration, suggesting that the vacancies affect the boron strengthening mechanism. The strength increase per unit increase in lattice parameter depends on the aluminum concentration and is 0.23-0.80 G, where G is the shear modulus. (C) 1997 Elsevier Science Limited. C1 Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Baker, I (reprint author), Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. RI George, Easo/L-5434-2014 NR 27 TC 35 Z9 36 U1 3 U2 10 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD MAY PY 1998 VL 6 IS 3 BP 177 EP 183 DI 10.1016/S0966-9795(97)00063-0 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA YZ248 UT WOS:000072235100003 ER PT J AU Kim, KJ Feldman, KT Lloyd, G Razani, A Shanahan, KL AF Kim, KJ Feldman, KT Lloyd, G Razani, A Shanahan, KL TI Performance of high power metal hydride reactors SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article ID THERMAL-CONDUCTIVITY AB Metal hydride reactors were built with porous powder metal hydride (PMH) compacts. An improved reactor built with copper coated PMH compacts of LaNi5 with a 1.27 cm diameter produced a nominal specific cooling power of 1.5 kW/kg hydride. A similar reactor, built with copper coated PMH compacts of Ca(0.4)Mm(0.6)Ni(5), showed 2.2 kW/kg hydride. Results with copper coated PMH compacts showed improved thermal conductivity. The compacts are structurally strong and prevent migration of fine metal hydride particles. Life-cycle tests were performed on the reactor with LaNi, for over 3000 cycles and the cooling power of the reactor gradually decreased by approximately 55%. (C) 1998 International Association for Hydrogen Energy. C1 Univ New Mexico, Dept Mech Engn, Albuquerque, NM 87131 USA. Thermal Elect Devices, Albuquerque, NM USA. Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Razani, A (reprint author), Univ New Mexico, Dept Mech Engn, Albuquerque, NM 87131 USA. NR 13 TC 38 Z9 39 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD MAY PY 1998 VL 23 IS 5 BP 355 EP 362 DI 10.1016/S0360-3199(97)00058-X PG 8 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA ZA284 UT WOS:000072348100007 ER PT J AU Naber, JD Siebers, DL AF Naber, JD Siebers, DL TI Hydrogen combustion under diesel engine conditions SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article AB The autoignition and combustion of hydrogen were investigated in a constant-volume combustion vessel under simulated direct-injection (DI) diesel engine conditions. The parameters varied in the investigation included: the injection pressure and temperature, the orifice diameter, and the ambient gas pressure, temperature and composition. The results show that the ignition delay of hydrogen under DI diesel conditions has a strong, Arrhenius dependence on temperature; however, the dependence on the other parameters examined is small. For gas densities typical of top-dead-center (TDC) in diesel engines, ignition delays of less than 1.0 ms were obtained for gas-temperatures greater than 1120 K with oxygen concentrations as low as 5% (by volume). These data confirm that compression ignition of hydrogen is possible in a diesel engine at reasonable TDC conditions. In addition, the results show that DI hydrogen combustion rates are insensitive to reduced oxygen concentrations. The insensitivity of ignition delay and combustion rate to reduced oxygen concentration is significant because it offers the potential for a dramatic reduction in the emission of nitric oxides from a compression-ignited DI hydrogen engine through use of exhaust-gas-recirculation. (C) 1998 International Association for Hydrogen Energy. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Naber, JD (reprint author), Motorola Inc, AIEG, Dearborn, MI 48120 USA. NR 18 TC 48 Z9 50 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD MAY PY 1998 VL 23 IS 5 BP 363 EP 371 DI 10.1016/S0360-3199(97)00083-9 PG 9 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA ZA284 UT WOS:000072348100008 ER PT J AU Pope, RM Shen, NZ Hofstadler, SA Dearden, DV AF Pope, RM Shen, NZ Hofstadler, SA Dearden, DV TI Gas phase stripping of alkali cations from biomolecules via reaction with crown ethers SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE alkali cations; crown ethers; gas phase stripping; gramicidin S ID NUCLEAR MAGNETIC-RESONANCE; MASS-SPECTROMETRY; CYCLIC-PEPTIDES; METAL-ION; CIRCULAR-DICHROISM; LITHIUM-CHLORIDE; CYCLOSPORINE-A; GRAMICIDIN-S; COMPLEXES; BINDING AB Electrospray mass spectra of biomolecules produced from salty solutions can exhibit a large number of alkali adducts. Often the number of attached alkali metal atoms exceeds the net charge state of the ion. For example, the spectral intensity of the 2+ charge state of gramicidin S, cyclo[Val-Orn-leu-D-Phe-Pro](2), (GS), withdrawn from a sodium-containing water:methanol solution, is distributed over (GS + 2H)(2+), (GS + H + Na)(2+), (GS + 2Na)(2+), (GS-H + 3Na)(2+), (GS-2H + 4Na)(2+), (GS-3H + 5Na)(2+), and (GS-4H + 6Na)(2+). Each additional metal cation displaces a proton without affecting the net charge of the biomolecule. Hence, in (GS-2H + 4Na)(2+), at least two of the alkali metal adducts must involve displacement of protons from non-traditional basic sites. The character of these coordination sites must be either "salt-like" or zwitterionic. Alkali adducts of trapped polypeptide ions may be removed via gas phase ion-molecule "stripping" reactions with crown ethers 12-crown-4, 15-crown-5, or 18-crown-6. Both products of the stripping reaction, the desalted biomolecule of reduced charge and the alkali-metal-attached crown, are observed in the FTICR mass spectra. For gas phase, ''hyper-metallated'' peptides, in which the number of adducted alkali metal ions exceeds the net charge, we suggest that some of the attached cations replace amide protons by coordinating as a salt or zwitterion to a tautomerized, deprotonated amide link in the backbone of the peptide. Alkali adduction to these non-traditional base sites leads to slightly higher stripping rates, probably by removing the secondary constraints of transannular NH ... O = C hydrogen bonds, which makes attached alkali cations more accessible to the stripping reagent. Stripping of K+ is faster than stripping of Na+, as may be expected for electrostatically bound cations. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dearden, DV (reprint author), Brigham Young Univ, Dept Chem & Biochem, C100 Benson Sci Bldg, Provo, UT 84602 USA. NR 33 TC 11 Z9 11 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD MAY PY 1998 VL 175 IS 1-2 BP 179 EP 186 DI 10.1016/S0168-1176(98)00121-9 PG 8 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA ZX918 UT WOS:000074568500018 ER PT J AU Ingram, JC Appelhans, AD Groenewold, GS AF Ingram, JC Appelhans, AD Groenewold, GS TI Ion-trap SIMS analysis of pinacolyl methylphosphonic acid on soil SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE secondary-ion mass spectrometry; ion trap; pinacolyl methylphosphonic acid; soil ID IONIZATION MASS-SPECTROMETRY; CHEMICAL WARFARE AGENTS; DEGRADATION PRODUCTS; STATIC SIMS; CHROMATOGRAPHY; SURFACES AB The minimum detection limit and semi-quantitative determination of surface coverages of pinacolyl methylphosphonic acid (PMPA) on soil by static secondary-ion mass spectrometry (SIMS) are reported. The soil was exposed to aqueous solutions of PMPA and then analyzed on an ion-trap SIMS instrument. Mass spectrometry/mass spectrometry was utilized to discriminate against the chemical background inherent in environmental samples (such as soil). The quasimolecular ion [PMPA - H](-) at m/z = 179 was trapped and then subsequently fragmented to form an ion at m/z = 95, which is interpreted as a loss of the pinacolyl olefin (C6H12) to form the methylphosphonic acid anion. The product ion at mit = 95 was used to investigate the surface coverage of PMPA on the soil. The m/z = 95 product-ion abundance was observed to be linearly related to the PMPA surface coverage between 2 and 0.002 monolayers. The minimum detection limit is estimated at 0.008 monolayer (approximately 12 pg mm(-2), three standard deviations of the blank). These data were compared with analyses performed by using a quadrupole SIMS instrument, which indicates an improvement in sensitivity by the ion-trap SIMS of a factor of 250. The results of this study demonstrate that ion-trap SIMS is a facile approach for determination of phosphonates on soil. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Ingram, JC (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 20 TC 24 Z9 24 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD MAY PY 1998 VL 175 IS 3 BP 253 EP 262 DI 10.1016/S0168-1176(98)00130-X PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA ZY449 UT WOS:000074622400003 ER PT J AU Cai, D Snell, CM Beardmore, KM Gronbech-Jensen, N AF Cai, D Snell, CM Beardmore, KM Gronbech-Jensen, N TI Simulation of phosphorus implantation into silicon with a single parameter electronic stopping power model SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article DE modeling ion implantation; silicon; binary collision; molecular dynamics; electronic stopping ID MONTE-CARLO SIMULATION; SLOW IONS; COMPUTER-SIMULATION; CRYSTAL SILICON; DEPENDENCE; CHARGES; SOLIDS; GAS AB We simulate dopant profiles for phosphorus implantation into silicon using a new model for electronic stopping power. In this model, the electronic stopping power is factorized into a globally averaged effective charge Z(1)* and a local charge density dependent electronic stopping power for a proton. There is only a single adjustable parameter in the model, namely the one electron radius r(s)(0) which controls Z(1)* By fine tuning this parameter, we obtain excellent agreement between simulated dopant profiles and the SIMS data over a wide range of energies for the channeling case. Our work provides a further example of implant species, in addition to boron and arsenic, to verify the validity of the electronic stopping power model and to illustrate its generality for studies of physical processes involving electronic stopping. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Cai, D (reprint author), NYU, Courant Inst Math Sci, 251 Mercer St, New York, NY 10012 USA. NR 28 TC 22 Z9 22 U1 1 U2 3 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD MAY PY 1998 VL 9 IS 3 BP 459 EP 470 DI 10.1142/S0129183198000352 PG 12 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZT463 UT WOS:000074090400006 ER PT J AU Lloyd, DC Moquet, JE Oram, S Edwards, AA Lucas, JN AF Lloyd, DC Moquet, JE Oram, S Edwards, AA Lucas, JN TI Accidental intake of tritiated water: a cytogenetic follow-up case on translocation stability and dose reconstruction SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID IN-SITU HYBRIDIZATION; CHROMOSOME EXCHANGES; FREQUENCY; RADIATION; ABERRATIONS; EXPOSURE AB Purpose: To examine by fluorescence in situ hybridization (FISH) chromosomal translocations in a person who, 11 years previously, had accidentally incorporated tritiated water. To compare the resultant estimate of radiation dose with contemporary dosimetry made by urine analysis and dicentric chromosome scoring. Materials and methods: Blood lymphocytes were shared by two laboratories each performing the FISH analysis using different chromosome probe combinations. Doses were calculated by reference to an in vitro calibration curve produced in one of the laboratories. Results: Good agreement in translocation yields was found by the two laboratories. Comparing the yields with the dicentric frequency obtained shortly after the accident and with a translocation frequency measured 6 years post exposure showed good agreement between all measurements. This indicates essentially perfect stability for translocations over an 11 year period in this individual. Conclusions: Dose reconstruction based on FISH-measured translocations showed good agreement with the dose estimated from initial dicentric measurements and from measurements of tritium in urine. Because of the extensive initial dosimetry performed on this individual, who received a uniform whole-body irradiation, the case serves as an excellent test for the use of FISH-measured translocations for retrospective biodosimetry. C1 Natl Radiol Protect Board, Didcot OX11 0RQ, Oxon, England. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Natl Radiol Protect Board, Didcot OX11 0RQ, Oxon, England. NR 17 TC 58 Z9 66 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0955-3002 EI 1362-3095 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD MAY PY 1998 VL 73 IS 5 BP 543 EP 547 PG 5 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA ZR534 UT WOS:000073987200011 PM 9652812 ER PT J AU Shu, JY Fleck, NA AF Shu, JY Fleck, NA TI The prediction of a size effect in micro-indentation SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article ID STRAIN GRADIENT PLASTICITY; HARDNESS AB The indentation hardness of metals depends upon the size of the indent. for indents in the size range of 0.1-10 mu m. A finite element method is used to predict this size effect, based on Fleck-Hutchinson strain gradient plasticity theory. The material is treated as a power law, deformation theory solid such that the strain energy density depends upon both strain and strain gradient. An indentation size effect is predicted for axisymmetric indenters of various head-shape (flat, conical and spherical), and the role of contact friction is explored. It is found that the predicted hardness increases significantly when the size of the indent is comparable to the material micro-length scale. (C) 1998 Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94551 USA. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. RP Shu, JY (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94551 USA. EM naf1@eng.cam.ac.uk NR 18 TC 135 Z9 145 U1 3 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD MAY PY 1998 VL 35 IS 13 BP 1363 EP 1383 DI 10.1016/S0020-7683(97)00112-1 PG 21 WC Mechanics SC Mechanics GA YZ360 UT WOS:000072246600005 ER PT J AU Paddison, SJ Tschuikow-Roux, E AF Paddison, SJ Tschuikow-Roux, E TI Thermodynamic properties of bromomethanes and bromomethyl radicals: An ab initio study SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, CO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE bromomethanes; bromomethyl radicals; enthalpies of formation; thermodynamic properties ID BOND-DISSOCIATION ENERGIES; METHYL-BROMIDE; DIBROMOMETHANE CH2BR2; ATMOSPHERIC CH3BR; BASIS-SETS; MOLECULES; ATOMS; OCEAN; HEATS; CL AB Thermochemical data on volatile organic compounds containing bromine are needed for atmospheric modeling, in view of their ozone depletion potential upon photodissociation and the release of atomic bromine. Yet even for the bromomethane series, with the exception of CH(3)Br, thermodynamic properties are not well established. Similarly, structural and thermochemical information on brominated methyl radicals is incomplete or not available. In this paper we have adopted a computational approach to obtain this needed information. Equilibrium geometries for the molecules CH(4-n)Br(n) (n=0-4) and radicals CH(3-m)Br(m) (nz=0-3) were optimized at both HF/6-31 G* and MP2/6-31 G* levels of theory. Moments of inertia, harmonic vibrational frequencies, and thermodynamic functions were determined at the HF/6-31G* level. Electron correlation contributions were performed by single-point calculations at both second- and fourth-order Moller-Plesset perturbation theory for derived MP2/6-31G*geometries. Enthalpies of formation were obtained from a consideration of applicable isodesmic reactions using the derived MP4/6-31G**//MP2/6-31G* total energies in conjunction with experimentally established enthalpies of formation for CH,Br, CH,, and CI-I,. These data were then used in the determination of Delta H degrees(f, T), Delta G degrees(f, T) and K(f, T) for all species over the temperature range 0 to 1500 K. A comparison was made to the existing standard enthalpies of formation at 298 K, both experimentally measured and theoretically estimated, for CH(2)Br(2), CHBr(3), CBr(4), CH(2)Br ., CHBr(2)., and CBr(3).. C1 Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP Paddison, SJ (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, MST-11,MS D429, Los Alamos, NM 87545 USA. RI Paddison, Stephen/B-2935-2014 NR 36 TC 7 Z9 7 U1 1 U2 3 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1998 VL 19 IS 3 BP 719 EP 730 DI 10.1023/A:1022670318235 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 126XU UT WOS:000076320900008 ER PT J AU Pitzer, KS Roy, RN Wang, P AF Pitzer, KS Roy, RN Wang, P TI Thermodynamics of the system InCl3-HCl-H2O at 25 degrees C SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE aqueous electrolytes; equation of state; indium chloride; Pitzer equation; thermodynamic properties ID SULFURIC-ACID; ELECTROLYTES AB A comprehensive equation for the thermodynamic properties of the system InCl3-HCl-H2O at 25 degrees C in the ion-interaction (Pitzer) equation form is generated on the basis of a very recent and comprehensive array of electrochemical-cell measurements of the HCl activity, together with older published measurements of the activity of InCl3 in mixtures with 0.02 molal HCL. Alternate equations with and without explicit consideration of the ion pair InCl2+ as a separate species are tested. Excellent agreement is obtained on either formulation between calculated and measured activities, although considerable uncertainty remains concerning the standard potential for the in electrode. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Drury Coll, Hoffman Dept Chem, Springfield, MO 65802 USA. RP Wang, P (reprint author), OLI Syst Inc, 108 Amer Rd, Morris Plains, NJ 07950 USA. NR 14 TC 2 Z9 2 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1998 VL 19 IS 3 BP 731 EP 738 DI 10.1023/A:1022622402306 PG 8 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 126XU UT WOS:000076320900009 ER PT J AU Wang, P Oakes, CS Pitzer, KS AF Wang, P Oakes, CS Pitzer, KS TI Thermodynamics of the system MgCl2-NaCl-H2O to 573 K: New measurements of heat of mixing and heat of dilution SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE aqueous electrolyte; calorimetry, heat of dilution; heat of mixing; high temperatures; magnesium chloride; Pitzer equation; sodium chloride; thermodynamic properties ID ELEVATED-TEMPERATURES; ISOPIESTIC MOLALITIES; MAGNESIUM-CHLORIDE; AQUEOUS-SOLUTIONS; MIXTURES; 25-DEGREES-C; ENTHALPIES; ACID; NACL; H2O AB Heats of mixing of NaCl(aq) with MgCl2(aq) at 373.15, 423.15, 473.15, 523.15, and 573.15 K for ionic strengths of 0.5 to 3.8 mol.kg(-1), and heats of dilution of MgCl2(aq) at 523.15 and 573.15 K for ionic strengths of 0.3 to 4.6 mol.kg(-1) have been measured at 20.5 MPa. These experimental data are combined with published heat of mixing data at 298 and 373 K to provide a comprehensive Fitter ion-interaction treatment for the thermodynamic properties of the NaCl-MgCl2-H2O system to 573 K. The treatment includes a general equation valid to 523 K, incorporating the published equations for NaCl(aq) and MgCl2(aq), and equations for MgCl2(aq) and the mixed system valid at 573 K. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wang, P (reprint author), OLI Syst Inc, 108 Amer Rd, Morris Plains, NJ 07950 USA. NR 24 TC 4 Z9 4 U1 1 U2 5 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1998 VL 19 IS 3 BP 739 EP 748 DI 10.1023/A:1022674419144 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 126XU UT WOS:000076320900010 ER PT J AU Sterner, SM Felmy, AR Oakes, CS Pitzer, KS AF Sterner, SM Felmy, AR Oakes, CS Pitzer, KS TI Correlation of thermodynamic data for aqueous electrolyte solutions to very high ionic strength using INSIGHT: Vapor saturated water activity in the system CaCl2-H2O to 250 degrees C and solid saturation SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE aqueous; calcium chloride; electrolyte; thermodynamics ID CALCIUM-CHLORIDE; ACTIVITY-COEFFICIENTS; TEMPERATURES; EQUILIBRIA; PREDICTION; ENTHALPIES; MOLALITIES; DILUTION AB Osmotic coefficients for the CaCl2-H2O system between 25 and 250 degrees C and from the dilute region to solid saturation or beyond (i.e., to approximate to 12 mCaCl(2) at the lowest temperature and approximate to 32 mCaCl(2) at the highest) have been correlated using the following permutations and modifications of the basic Fitter ion-interaction equation: (1) the basic Fitter equation, (2) the Fitter equation augmented by an ionic strength-dependent third virial contribution, (3) the Fitter equation together with equilibria involving the formation of CaCl+ and CaCl20, and (4) the simultaneous combination of all of the above. The effectiveness, accuracy, and practicality of each approach are reviewed. C1 Pacific NW Lab, Thermodynam & Mol Geochem Grp, Richland, WA 99352 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sterner, SM (reprint author), Fluid Inclus Technol Inc, 2217 N Yellowood Ave, Broken Arrow, OK 74012 USA. NR 17 TC 15 Z9 15 U1 4 U2 6 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1998 VL 19 IS 3 BP 761 EP 770 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 126XU UT WOS:000076320900012 ER PT J AU Conry, MJ AF Conry, MJ TI Influence of seed rate and sowing date on the yield and grain quality of Blenheim spring malting barley in the south-east of Ireland SO JOURNAL OF AGRICULTURAL SCIENCE LA English DT Article AB The effect of four seed rates on the grain yield, grain N content and grain size of Blenheim malting barley sown on two dates in the spring was tested on three different soils over a 4-year period (1991-94). The four seed rates (120, 160, 200 and 240 kg/ha) gave mean plant populations of 222, 308, 374 and 430 plants/m(2), respectively, for the first sowing date (February to early March) and 235, 340, 405 and 470 plants/m(2) for the second sowing date, 3-5 weeks later (late March to mid-April). The earlier-sown crops generally gave greater yield, lower grain N and smaller amount of screenings, but in two of the twelve experiments, the first sowing gave lower yield and greater grain N. The influence of seed rate on yield and quality depended on sowing date. The three higher seed rates (160, 200, 240 kg/ha) had little influence on yield or grain N, irrespective of sowing date, and there was no significant difference in yield between the lowest (120 kg/ha) and the three higher seed rates when the crop was sown in February and early March. But when the crops were sown in April, the lowest seed rate (120 kg/ha) gave the lowest yield in all seven comparisons and gave significantly reduced yield in three of the seven comparisons. There was a significant increase in grain N in three of the comparisons. Seed rate had little effect on grain screenings or 1000-grain weight. Soil differences did not influence the effect of seed rate on the yield and quality of the grain. C1 Oak Pk Res Ctr, Carlow, Ireland. RP Conry, MJ (reprint author), Oak Pk Res Ctr, Carlow, Ireland. NR 17 TC 2 Z9 3 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0021-8596 J9 J AGR SCI JI J. Agric. Sci. PD MAY PY 1998 VL 130 BP 307 EP 315 DI 10.1017/S0021859698005267 PN 3 PG 9 WC Agriculture, Multidisciplinary SC Agriculture GA ZQ825 UT WOS:000073906700005 ER PT J AU Eller, PG Malm, JG Swanson, BI Morss, LR AF Eller, PG Malm, JG Swanson, BI Morss, LR TI Reactions of hexafluorides of uranium, neptunium, and plutonium with nitrogen oxides and oxyfluorides. Synthesis and characterization of (NO)[NpF6] and (NO)[PuF6] SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE hexafluorides; nitrogen oxides; oxyfluorides; plutonium; neptunium; uranium ID SALTS AB A comparative study has been performed of the reactions of nitric oxide (NO), nitrogen dioxide (NO2), nitrosyl fluoride (FNO), nitryl fluoride (FNO2), and nitrogen oxytrifluoride (F3NO) with the hexafluorides of uranium, neptunium, and plutonium. Significant chemical differences among the hexafluorides were found. Thus, UF6 and excess NO reacted at room temperature to form the nitrosonium salt (NO)[UF6], the same U(V) product formed from the reaction of UF6 with excess NO2. Excess NO reacted rapidly with NpF6 to form poorly crystalline Np(IV) solids, but with an equimolar amount of PuF6 at reduced temperature NO reacted to yield a mixture of Pu(IV) species and the new compound (NO)[PuF6]. With NpF6, FNO reacted only under photolytic conditions to give (NO)[NpF6], whereas PuF6 oxidized FNO to give F3NO and a mixture of (NO)[PuF6] and Pu(IV) solids. No reaction was observed between NpF6 or PuF6 with FNO2. Likewise, no reaction was observed between F3NO and the actinide hexafluorides, even under photolytic conditions. (C) 1998 Elsevier Science S.A. C1 Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci Technol Div, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Eller, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 3 Z9 3 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 1 PY 1998 VL 269 IS 1-2 BP 50 EP 56 DI 10.1016/S0925-8388(98)00155-8 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA ZT716 UT WOS:000074117500015 ER PT J AU Eller, PG Asprey, LB Kinkead, SA Swanson, BI Kissane, RJ AF Eller, PG Asprey, LB Kinkead, SA Swanson, BI Kissane, RJ TI Reactions of dioxygen difluoride with neptunium oxides and fluorides SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE neptunium tetrafluoride; neptunium dioxide; dioxygen difluoride; neptunium hexafluoride ID VIBRATIONAL INTENSITY; TEMPERATURE; PLUTONIUM; MONOFLUORIDE; LANTHANIDES; ACTINIDES AB Neptunium dioxide and tetrafluoride are converted in essentially quantitative yield to volatile neptunium hexafluoride by dioxygen difluoride (O2F2), both in gas-solid reactions at ambient temperatures and in liquid anhydrous hydrogen fluoride at -78 degrees C. Neptunium dioxydiAuoride was identified by Raman spectroscopy as a dominant reaction intermediate in the neptunium dioxide reaction. Direct reaction of NpF4 with liquid O2F2 resulted in violent decomposition of O2F2 with little or no conversion to NpF6. These reaction temperatures contrast markedly with the elevated temperatures (above 200 degrees C) required for NpF6 generation using elemental fluorine or halogen fluorides. (C) 1998 Elsevier Science S.A. C1 Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Dynam Expt Div, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Chem Sci Technol Div, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Los Alamos, NM 87544 USA. RP Eller, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87544 USA. NR 29 TC 1 Z9 2 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 1 PY 1998 VL 269 IS 1-2 BP 63 EP 66 DI 10.1016/S0925-8388(98)00005-X PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA ZT716 UT WOS:000074117500018 ER PT J AU Buchheit, RG AF Buchheit, RG TI Copper removal during formation of corrosion resistant alkaline oxide coatings on Al-Cu-Mg alloys SO JOURNAL OF APPLIED ELECTROCHEMISTRY LA English DT Article DE copper; alloy; copper enrichment; copper removal ID ALUMINUM AB The performance of corrosion resistant inorganic oxide coatings formed on Al-Cu-Mg alloys is often degraded by Cu enrichment that occurs during oxide formation. This is particularly true of coating processes conducted in basic solutions. A modification to an alkaline oxide coating process has been made that simultaneously eliminates Cu enrichment and forms a corrosion resistant coating. In this paper, the modified process is described and the resulting coating morphology, structure and composition are reported. Results from electrochemical and exposure corrosion tests show that useful gains in corrosion resistance are achieved. Cu removal during the modified process is rationalized using an argument based on the increase in Cu solubility that occurs in solutions with a pH greater than the solubility minimum for Cu (9.8), and the effect of Cu complexing by carbonate. C1 Sandia Natl Labs, Mech Met & Corros Dept, Albuquerque, NM 87185 USA. RP Buchheit, RG (reprint author), Sandia Natl Labs, Mech Met & Corros Dept, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 16 Z9 16 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0021-891X J9 J APPL ELECTROCHEM JI J. Appl. Electrochem. PD MAY PY 1998 VL 28 IS 5 BP 503 EP 510 DI 10.1023/A:1003217211727 PG 8 WC Electrochemistry SC Electrochemistry GA ZE905 UT WOS:000072843400004 ER PT J AU Martin, SJ Butler, MA Spates, JJ Mitchell, MA Schubert, WK AF Martin, SJ Butler, MA Spates, JJ Mitchell, MA Schubert, WK TI Flexural plate wave resonator excited with Lorentz forces SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SENSOR AB A flexural plate wave resonator was constructed by patterning current lines on a silicon nitride membrane suspended on a rectangular silicon frame. Eigenmodes of the rectangular membrane were excited using Lorentz forces generated between alternating surface currents and a static in-plane magnetic field. Preferential coupling to a particular membrane mode was achieved by positioning current lines along longitudinal mode antinodes. An equivalent-circuit model was derived which characterizes the input impedance of a one-port device and the transmission response of a two-port device over a range of frequencies near a single membrane resonance. Experiments were performed to characterize the device's response to changes in de magnetic field strength, ambient gas composition, gas pressure, and input power. C1 Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. RP Martin, SJ (reprint author), Sandia Natl Labs, Microsensor Res & Dev Dept, POB 5800, Albuquerque, NM 87185 USA. NR 20 TC 25 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4589 EP 4601 DI 10.1063/1.367242 PG 13 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900006 ER PT J AU Ridgway, MC Glover, CJ Foran, GJ Yu, KM AF Ridgway, MC Glover, CJ Foran, GJ Yu, KM TI Characterization of the local structure of amorphous GaAs produced by ion implantation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BINDING MOLECULAR-DYNAMICS; ABSORPTION FINE-STRUCTURE; GALLIUM-ARSENIDE; DEFECTS; EXAFS; PROGRAM; GROWTH AB The first report of the structural parameters of amorphous GaAs produced by ion implantation, as determined with extended x-ray absorption fine structure measurements, is presented herein. Relative to a crystalline sample, the nearest-neighbor bond length and Debye-Waller factor both increased for amorphized material. In contrast, the coordination numbers about both Ga and As atoms in the amorphous phase decreased to similar to 3.85 atoms from the crystalline value of four. All structural parameters were independent of both implant temperature and ion dose, the latter extending two orders of magnitude beyond that required for amorphization, and as a consequence, were considered representative of intrinsic, amorphous GaAs as opposed to an implantation-induced extrinsic structure. (C) 1998 American Institute of Physics. C1 Australian Natl Univ, Dept Elect Mat Engn, Res Sch Phys Sci & Engn, Canberra, ACT, Australia. Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Ridgway, MC (reprint author), Australian Natl Univ, Dept Elect Mat Engn, Res Sch Phys Sci & Engn, Canberra, ACT, Australia. RI Yu, Kin Man/J-1399-2012; Ridgway, Mark/D-9626-2011 OI Yu, Kin Man/0000-0003-1350-9642; Ridgway, Mark/0000-0002-0642-0108 NR 30 TC 37 Z9 37 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4610 EP 4614 DI 10.1063/1.367244 PG 5 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900008 ER PT J AU Parkhutik, VP AF Parkhutik, VP TI Self-organization of pores in SiC/Si composite structures SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SILICON; GROWTH; ANODIZATION; MORPHOLOGY; PHYSICS; MODELS; FILMS AB Anodic dissolution of a structure composed of the chemically vapor deposited amorphous SiC film and silicon wafer results in the formation of a system of hexagonally ordered pore colonies. This intriguing effect takes place when the structure SiC/Si is subjected to a short-time (several seconds) anodization in 48% HF/ethylene glycol solution. As a result of this procedure the SiC layer is converted into a porous one with diameters of the pores not exceeding 30-50 nm. Continuing the anodization-process beyond the complete conversion of SiC layer into a porous one results in porous structure formation in an underlying Si wafer. It appears that pores in silicon form colonies arranged in hexagonal order. Characteristic distance between neighboring colonies increases with the anodic I current density applied during the electrochemical process. It is assumed that the effect of self-ordered pore colonies growth is due to the accumulation of mechanical stress at SiC/Si interface due to a lattice mismatch and dynamic pressure developed in the pores during the anodic dissolution reaction. (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Parkhutik, VP (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4647 EP 4651 DI 10.1063/1.367250 PG 5 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900014 ER PT J AU Habermehl, S AF Habermehl, S TI Stress relaxation in Si-rich silicon nitride thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; X-RAY MASK; DIELECTRIC FUNCTION; OPTICAL-PROPERTIES; GROWTH AB Si-rich silicon nitride thin films have been deposited by low pressure chemical vapor deposition, at 850 degrees C from mixtures of dichlorosilane and ammonia. The films' elastic properties have been studied as a function of film composition. Fourier transform infrared spectroscopy and ellipsometric data indicate that the local atomic strain is a strong function of the calculated volume fraction of Si contained in the films. A relationship is observed that shows the strain to be inversely proportional to the cube root of the Si volume fraction. A model that accounts for distortion in Si-SixN4-x tetrahedra (x=0-4), upon substitution of silicon for nitrogen in the film is applied to the data. The model is shown to be consistent with measurements of intrinsic film stress across a compositional range from stoichiometric silicon nitride, Si3N4, to nitrogen-free amorphous silicon, a-Si. (C) 1998 American Institute of Physics. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Habermehl, S (reprint author), Sandia Natl Labs, POB 5800,M S 1084, Albuquerque, NM 87185 USA. NR 30 TC 46 Z9 46 U1 3 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4672 EP 4677 DI 10.1063/1.367253 PG 6 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900017 ER PT J AU Mahan, GD Sofo, JO Bartkowiak, M AF Mahan, GD Sofo, JO Bartkowiak, M TI Multilayer thermionic refrigerator and generator SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAAS/ALAS AB A new method of refrigeration is proposed. Cooling is obtained by thermionic emission of electrons over periodic barriers in a multilayer geometry. These could be either Schottky barriers between metals and semiconductors or else barriers in a semiconductor superlattice. The same device is an efficient power generator. A complete theory is provided. (C) 1998 American Institute of Physics. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Inst Balseiro, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. RP Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RI Sofo, Jorge/J-4415-2012; Sofo, Jorge/B-4344-2014 OI Sofo, Jorge/0000-0003-4513-3694; Sofo, Jorge/0000-0003-4513-3694 NR 24 TC 103 Z9 107 U1 3 U2 24 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4683 EP 4689 DI 10.1063/1.367255 PG 7 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900019 ER PT J AU Adams, DP Mayer, TM Swartzentruber, BS AF Adams, DP Mayer, TM Swartzentruber, BS TI Influence of interfacial hydrogen on Al thin film nucleation on Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; CHEMICAL-VAPOR-DEPOSITION; EPITAXIAL-GROWTH; SI(100) SURFACE; MOLECULAR-BEAM; DESORPTION; DIFFUSION; ALUMINUM; SI(001); DECOMPOSITION AB We use scanning tunneling microscopy to study the coverage-dependent effects of hydrogen on Al thin film nucleation on Si(100). Using a quench-and-look procedure we find that small amounts of H affect Al island structure. Specifically, Al films deposited onto Si having 0.15 monolayer of adsorbed monohydride show an increased island density and a preponderance of small (less than or equal to 4 atom) clusters, compared with growth on clean Si. We interpret this to be a result of reduced Al adatom diffusion lengths due to site blocking or trapping. Also, the effects of a full monolayer of hydrogen on Al thin film morphology are studied. Al deposited onto Si(100) terminated with a layer of monohydride forms three-dimensional islands, unlike growth on clean Si. Although a change in growth morphology is observed in thin Al films, the out-of-plane crystal texture of thick Al films (300-1000 Angstrom) is unaffected by a monolayer of interfacial hydrogen. Hydrogen is not present at a Si-Al interface after thick film growth at 100 degrees C on fully passivated substrates. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Adams, DP (reprint author), Sandia Natl Labs, POB 5800,MS 0959, Albuquerque, NM 87185 USA. NR 38 TC 8 Z9 8 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4690 EP 4694 DI 10.1063/1.367256 PG 5 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900020 ER PT J AU Armstrong, RA Shorter, JA Taylor, MJ Suszcynsky, DM Lyons, WA Jeong, LS AF Armstrong, RA Shorter, JA Taylor, MJ Suszcynsky, DM Lyons, WA Jeong, LS TI Photometric measurements in the SPRITES '95 & '96 campaigns of nitrogen second positive (399.8 nm) and first negative (427.8 nm) emissions SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID IONIZATION; BAND; STRATOSPHERE; EXCITATION; DISCHARGES; AIRCRAFT AB We have obtained blue photometric measurements of the N-2 second positive 399.8 nm and the N-2(+) first negative 427.8 nm emission from sprites, elves and lightning, along with supporting video images. The pulse width and intensity results for sprites are consistent with those of Suszcynsky et al. (1998). The red emission from sprites has been independently and unambiguously identified by Hampton et al. (1996) and Mende et al. (1995) as the nitrogen first positive band. The source has been attributed to electron impact excitation from low energy electrons(approximate to 1 eV) in the sprite. The short pulse width of the 427.8 nm and 399.8 nm photometer rime traces obtained in this investigation are probably not from the same source that produces the red emission. The results reported here indicate an initial energetic ionizing event sufficient to ionize and excite nitrogen followed by secondary electron processes which give rise to the dominant red emission. The photometer results for elves are consistent with the EMP mechanism suggested by Inan et al. (1996). The photometer traces obtained for lightning indicate emissions consistent with a 'continuing current' as the charge redistributes within the thunderstorm cloud. We find that the ratio of the intensity of the 399.8 nm N-2(2P) emission to that of 427.8 nm N-2(+) (1N) emission can be used to discriminate among sprites, elves and lightning. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Mission Res Corp, Nashua, NH 03062 USA. Utah State Univ, Logan, UT 84332 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. FMA Res, Ft Collins, CO 80524 USA. USAF, Phillips Lab, GPOS, Hanscom AFB, MA 01731 USA. RP Armstrong, RA (reprint author), Mission Res Corp, 1 Tara Blvd, Nashua, NH 03062 USA. NR 42 TC 50 Z9 50 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY-JUN PY 1998 VL 60 IS 7-9 BP 787 EP 799 DI 10.1016/S1364-6826(98)00026-1 PG 13 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 124QP UT WOS:000076193500014 ER PT J AU Suszcynsky, DM Roussel-Dupre, R Lyons, WA Armstrong, RA AF Suszcynsky, DM Roussel-Dupre, R Lyons, WA Armstrong, RA TI Blue-light imagery and photometry of sprites SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID ELECTROSTATIC THUNDERCLOUD FIELDS; ELECTROMAGNETIC PULSES; LOWER IONOSPHERE; RED-SPRITES; DISCHARGES; IONIZATION; MESOSPHERE; EXCITATION; BREAKDOWN; AIRCRAFT AB We have obtained blue (350-475 nm) video images and simultaneous high-time resolution narrow-band blue (415-435 nm) photometry records of four sprite events. The brightest blue images show a sustained tendril geometry and a nearly constant intensity of emission over the entire vertical extent of the sprite (from 35-90 km altitude). Photometer light curves display an exponential decay with a 0.3 ms time constant, a FWHM on the order of 0.1-1.0 ms, and are probably dominated by 427.8 nm (N-2(+) 1N) emission. The data support the observations of Armstrong et al. (1998) and support the contention that significant ionization occurs during sprite generation. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. FMA Res, Ft Collins, CO 80524 USA. Mission Res Corp, Nashua, NH 03062 USA. RP Suszcynsky, DM (reprint author), Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, POB 1663, Los Alamos, NM 87545 USA. EM dsuszcynsky@lanl.gov NR 27 TC 41 Z9 41 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY-JUN PY 1998 VL 60 IS 7-9 BP 801 EP 809 DI 10.1016/S1364-6826(98)00027-3 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 124QP UT WOS:000076193500015 ER PT J AU Roussel-Dupre, R Symbalisty, E Taranenko, Y Yukhimuk, V AF Roussel-Dupre, R Symbalisty, E Taranenko, Y Yukhimuk, V TI Simulations of high-altitude discharges initiated by runaway breakdown SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID ELECTROSTATIC THUNDERCLOUD FIELDS; SPRITES94 AIRCRAFT CAMPAIGN; GAMMA-RAY FLASHES; LOWER IONOSPHERE; AIR-BREAKDOWN; ELECTROMAGNETIC PULSES; OPTICAL FLASHES; RED-SPRITES; X-RAYS; IONIZATION AB Detailed 2D hydrodynamic and quasi-electrostatic simulations of high-altitude discharges driven by runaway air breakdown are presented for four cases, corresponding to sprites initiated by positive cloud-to-ground lightning strikes in which 200 C of charge is neutralized at an altitude of 11.5 km in 10, 7, 5 and 3 ms. We find that the computed optical emissions agree well with low-light level camera images of sprites, both in terms of the overall intensity and spatial distribution of the emissions. Our results show the presence of blue emissions extending down to 40 km (blue tendrils) and red sprite tops extending from 50 to 77 km. Simulated spectra show that N-2 1st positive emissions dominate in the wavelength range from 550 to 850 nm, in good agreement with observations. Strong radio pulses with durations of similar to 300 mu s and peak electric field amplitudes ranging from 20 to 75 V/m at an altitude of 80 km and an approximate distance from the discharge of 50 km were computed. The magnitude and duration of these pulses is sufficient to cause breakdown and heating of the lower ionosphere (80-95 km) and leads us to suggest that sprites may also launch the EMP responsible for the production of elves. The computed values for the gamma-ray fluxes are in agreement with observations of gamma-ray bursts of atmospheric origin and the peak secondary electron densities which we obtain are in good agreement with recent measurements of HF echoes at mesospheric heights and associated with lightning. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. RP Roussel-Dupre, R (reprint author), Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, MS D466, Los Alamos, NM 87545 USA. EM rroussel-dupre@lanl.gov NR 59 TC 53 Z9 55 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY-JUN PY 1998 VL 60 IS 7-9 BP 917 EP 940 DI 10.1016/S1364-6826(98)00028-5 PG 24 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 124QP UT WOS:000076193500024 ER PT J AU Ignatius, MJ Sawhney, N Gupta, A Thibadeau, BM Monteiro, OR Brown, IG AF Ignatius, MJ Sawhney, N Gupta, A Thibadeau, BM Monteiro, OR Brown, IG TI Bioactive surface coatings for nanoscale instruments: Effects on CNS neurons SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE biocompatible; neuron growth; plasma deposition; ultrathin films; extracellular matrix; regeneration ID EXTRACELLULAR-MATRIX MOLECULES; INTRACORTICAL ELECTRODE ARRAY; CATHODIC-ARC DEPOSITION; METAL PLASMA IMMERSION; VOLTAGE-SENSITIVE DYES; CELLS IN-VITRO; RECORDING ELECTRODES; ION-IMPLANTATION; CORTICAL TISSUE; GROWTH AB A method is described for depositing onto medical instruments highly biocompatible and bioactive surface coatings that can promote and stabilize cell attachment. The coatings were made by first depositing thin films of materials, such as diamond-like carbon, or metals, including tantalum, tungsten, platinum, gold, iridium, palladium, and brass. These surfaces were further altered to either promote or inhibit cell growth and spreading by an additional over-coat of biological materials, including the extracellular matrix proteins, laminin, fibronectin, and collagen IV. The deposition technique used a metal or carbon plasma, and the important properties of film adhesion, hardness, density, and smoothness are tailored by control of the ion bombardment energy. The films are translucent enough to permit high resolution light microscopy for rapid and detailed examination of tissue response. These bioactive substrates have been tested on primary central nervous system neurons, and the growth response is excellent. Equally successful ha ve been our attempts to anchor neurons, without associated proliferation of non-neuronal cells, using coatings of poly-d-lysine. The method and the materials could have important ramifications in a number of areas of research and biotechnology, for example for chronic implantation of microelectrode arrays in the cerebral cortex for neuroprosthetic and neural monitoring application and for research on the human central nervous system. Possible applications in non-neuronal fields, such as for coronary artery stents and pace-maker electrodes, also are discussed. (C) 1998 John Wiley & Sons, Inc. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ignatius, MJ (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, Rm 361 LSA, Berkeley, CA 94720 USA. EM mji@uclink4.berkeley.edu FU NINDS NIH HHS [1R01NS31366] NR 48 TC 55 Z9 58 U1 2 U2 11 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD MAY PY 1998 VL 40 IS 2 BP 264 EP 274 DI 10.1002/(SICI)1097-4636(199805)40:2<264::AID-JBM11>3.0.CO;2-M PG 11 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA ZD360 UT WOS:000072677400011 PM 9549621 ER PT J AU Pelton, JG Comolli, LR AF Pelton, JG Comolli, LR TI Sequence specific (HN)-H-1, N-15, H-1(alpha), C-13(alpha) and C-13(beta) assignments for RNA-1 modulator protein ROM SO JOURNAL OF BIOMOLECULAR NMR LA English DT Article DE antisense RNA; NMR assignments; RNA-protein complex; ROP C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Struct Biol Div, Berkeley, CA 94710 USA. RP Pelton, JG (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM 10840] NR 10 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0925-2738 J9 J BIOMOL NMR JI J. Biomol. NMR PD MAY PY 1998 VL 11 IS 4 BP 463 EP 464 DI 10.1023/A:1008283704026 PG 2 WC Biochemistry & Molecular Biology; Spectroscopy SC Biochemistry & Molecular Biology; Spectroscopy GA 100HV UT WOS:000074811500013 PM 9691290 ER PT J AU Kinney, JH Ladd, AJC AF Kinney, JH Ladd, AJC TI The relationship between three-dimensional connectivity and the elastic properties of trabecular bone SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Article ID CANCELLOUS BONE; OVARIECTOMIZED RATS; PARATHYROID-HORMONE; MASS; OSTEOPOROSIS; ARCHITECTURE; MICROSCOPY; VOLUME AB A finite-element model was used to explore the relationship between connectivity density and the elastic modulus of trabecular bone, Six cubic specimens of trabecular bone, three prepared from human distal radii and three from L1 vertebrae, were imaged with synchrotron microtomography, The three-dimensional images were reconstructed into binary volumes of mineralized bone and soft tissue, and incorporated into the finite-element model. The relationship between three-dimensional connectivity and elastic modulus was explored by uniform thinning (atrophy) and thickening (recovery) of the trabecular bone. Though no functional relationship was found between connectivity and elastic modulus, there was a linear relationship, after a full cycle of atrophy and recovery, between the loss of elastic modulus and the overall loss of connectivity. The results indicate that recovery of mechanical function depends on preserving or restoring trabecular connectivity. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94551 USA. RP Kinney, JH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94551 USA. NR 28 TC 90 Z9 91 U1 2 U2 5 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD MAY PY 1998 VL 13 IS 5 BP 839 EP 845 DI 10.1359/jbmr.1998.13.5.839 PG 7 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA ZM928 UT WOS:000073590400010 PM 9610748 ER PT J AU Kettler, RM Wesolowski, DJ Palmer, DA AF Kettler, RM Wesolowski, DJ Palmer, DA TI Dissociation constants of oxalic acid in aqueous sodium chloride and sodium trifluoromethanesulfonate media to 175 degrees C SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID QUOTIENTS; WATER; 300-DEGREES-C; IONIZATION; COMPLEXATION; TEMPERATURE; EQUILIBRIA; OXALATE; PRODUCT; DESIGN AB The first and second molal dissociation constants of oxalic acid were measured potentiometrically in a concentration cell fitted with hydrogen electrodes. Measurements were made at six temperatures ranging from 5 degrees C to 125 degrees C at four ionic strengths ranging from 0.1 mol.kg(-1) to 1.0 mol.kg(-1) (NaCl and NaCF3SO3). The second molal dissociation constant was measured in NaCF3SO3 media only. The data obtained in this study were combined with the corresponding literature values, including a number of recalculated Harned cell and concentration cell measurements and previous results from this laboratory. Data for first molal dissociation constant obtained in the two ionic media were regressed simultaneously to yield a five-term equation that describes the dissociation in the anionic form. The thermodynamic properties obtained at 25 degrees C and infinite dilution are: log K-1a(theta) = -1.401 +/- 0.052, Delta H-1a = (-0.7 +/- 0.7) kJ.mol(-1), Delta S-1a = (-29 +/- 2) J.K-1 mol(-1), and Delta C-p,C-1a = (-231 +/- 6) J.K-1 mol(-1). Similar treatment of the original and recalculated data for the second molal dissociation constant yielded a nine-term equation and the following values at 25 degrees C and infinite dilution: log K-2a(theta) = -4.264 +/- 0.014, Delta H-2a = (-7.3 +/- 0.5) kJ.mol(-1), Delta S-2a = (-106 +/- 2) J.K-1 mol(-1), and Delta C-p,C-2a = (-229 +/- 27) J.K-1.mol(-1). C1 Univ Nebraska, Dept Geol, Lincoln, NE 68588 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN USA. RP Kettler, RM (reprint author), Univ Nebraska, Dept Geol, Lincoln, NE 68588 USA. NR 49 TC 27 Z9 27 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 1998 VL 43 IS 3 BP 337 EP 350 DI 10.1021/je970195z PG 14 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA ZP614 UT WOS:000073771100012 ER PT J AU Faulon, JL AF Faulon, JL TI Isomorphism, automorphism partitioning, and canonical labeling can be solved in polynomial-time for molecular graphs SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Article ID TOPOLOGICAL SYMMETRY; EQUIVALENCE CLASSES; ALGORITHM; PERCEPTION; ATOMS AB The graph isomorphism problem belongs to the class of NP problems, and has been conjectured intractable, although probably not NP-complete. However, in the context of chemistry, because molecules are a restricted class of graphs, the problem of graph isomorphism can be solved efficiently (i.e., in polynomial-time). This paper presents the theoretical results that for all molecules, the problems of isomorphism, automorphism partitioning, and canonical labeling are polynomial-time problems. Simple polynomial-time algorithms are also given for planar molecular graphs and used for automorphism partitioning of paraffins, polycyclic aromatic hydrocarbons (PAHs), fullerenes, and nanotubes. C1 Sandia Natl Labs, Computat Mat Sci Dept, Albuquerque, NM 87185 USA. RP Faulon, JL (reprint author), Sandia Natl Labs, Computat Mat Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 33 TC 39 Z9 39 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAY-JUN PY 1998 VL 38 IS 3 BP 432 EP 444 DI 10.1021/ci9702914 PG 13 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA ZP543 UT WOS:000073764000013 ER PT J AU Wei, GW Althorpe, SC Kouri, DJ Hoffman, DK AF Wei, GW Althorpe, SC Kouri, DJ Hoffman, DK TI An application of distributed approximating functional-wavelets to reactive scattering SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISCRETE AB A newly developed distributed approximating functional (DAF)-wavelet, the Dirichlet-Gabor DAF-wavelet (DGDW), is applied in a calculation of the state-to-state reaction probabilities for the three-dimensional (3-D) (J=0)H+H-2 reaction, using the time-independent wave-packet reactant-product decoupling (TIWRPD) method. The DGDWs are reconstructed from a rigorous mathematical sampling theorem, and are shown to be DAF-wavelet generalizations of both the sine discrete variable representation (sinc-DVR) and the Fourier distributed approximating functionals (DAFs). An important feature of the generalized sinc DVR representation is thar the grid points are distributed at equally spaced intervals and the kinetic energy matrix has a banded, Toeplitz structure. Test calculations show that, in accordance with mathematical sampling theory, the DAF-windowed sinc-DVR converges much more rapidly and to higher accuracy with bandwidth, 2W+1. The results of the H+H-2 calculation are in very close agreement with the results of previous TIWRPD calculations, demonstrating that the DGDW representation is an accurate and efficient representation for use in FFT wave-packet propagation methods, and that, more generally, the theory of wavelets and related techniques have great potential for the study of molecular dynamics. (C) 1998 American Institute of Physics. C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Wei, GW (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. RI Wei, Guowei /E-1852-2011 NR 28 TC 25 Z9 26 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1998 VL 108 IS 17 BP 7065 EP 7069 DI 10.1063/1.476125 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZK384 UT WOS:000073315200005 ER PT J AU Pratt, ST AF Pratt, ST TI Vibrational autoionization and predissociation in high Rydberg states of nitric oxide SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID QUANTUM-DEFECT THEORY; PHOTOELECTRON ANGULAR-DISTRIBUTIONS; THRESHOLD PHOTOIONIZATION SPECTRUM; RESONANCE MULTIPHOTON IONIZATION; HIGHER EXCITED-STATES; JET-COOLED ANILINE; BRANCHING RATIOS; HIGH-RESOLUTION; MAGNETIC-FIELD; SELECTION-RULES AB New results on the competition between autoionization and predissociation in the high Rydberg states of nitric oxide are presented. These results provide insight into the earlier work of Park ct al. [Phys. Rev. Lett. 76, 1591 (1996)] that shows evidence for substantial mixing between Rydberg series and ionization continua with even and odd orbital angular momenta (I). New data based on fluorescence-dip spectroscopy, detection of neutral predissociation products, and photoelectron spectroscopy suggest that the A'(2) Sigma(+) and I-2 Sigma(+) dissociative valence states play an important role in this I mixing. Zeeman splittings observed in a magnetic bottle electron spectrometer also result in an improvement in the assignment of these high Rydberg states. (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Pratt, ST (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 64 TC 18 Z9 18 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1998 VL 108 IS 17 BP 7131 EP 7140 DI 10.1063/1.476130 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZK384 UT WOS:000073315200011 ER PT J AU Luscombe, JH Luban, M Borsa, F AF Luscombe, JH Luban, M Borsa, F TI Classical Heisenberg model of magnetic molecular rings clusters: Accurate approximants for correlation functions and susceptibility SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYSTEMS AB We show that the measured magnetic susceptibility of molecular ring clusters can be accurately reproduced, for all but low temperatures T, by a classical Heisenberg model of N identical spins S on a ring that interact with isotropic nearest-neighbor interactions. While exact expressions for the two-spin correlation function, C-N(n,T), and the zero-held magnetic susceptibility, chi(N)(T), are known for the classical Heisenberg ring, their evaluation involves summing infinite series of modified spherical Bessel functions. By contrast, the formula C-N(n,T)=(u(n)+u(N-n))/(1+u(N)), where u(K)=cothK-K-1 is the Langevin function and K=JS(S+1)/(k(B)T) is the nearest-neighbor dimensionless coupling constant, provides an excellent approximation if N greater than or equal to 6 for the regime \K\<3. This choice of approximant combines the expected exponential decay of correlations for increasing yet small values of n, with the cyclic boundary condition for a finite ring, C-N(n,T)=C-N(N-n,T), By way of illustration, we show that, for T>50 K, the associated approximant for the susceptibility derived from the approximate correlation function is virtually indistinguishable from both the exact theoretical susceptibility and the experimental data for the "ferric wheel" molecular cluster ([Fe(OCH3)(2)(O2CCH2Cl)](10)), which contains N=10 interacting Fe3+ ions, each of spin S=5/2, that are symmetrically positioned in a nearly planar ring. (C) 1998 American Institute of Physics. C1 USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Univ Pavia, Dept Phys, I-27100 Pavia, Italy. RP Luscombe, JH (reprint author), USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. NR 14 TC 17 Z9 17 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1998 VL 108 IS 17 BP 7266 EP 7273 DI 10.1063/1.476144 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZK384 UT WOS:000073315200025 ER PT J AU Sharma, AK Clauss, SA Mong, GM Wahl, KL Campbell, JA AF Sharma, AK Clauss, SA Mong, GM Wahl, KL Campbell, JA TI Analysis and quantification of organic acids in simulated Hanford tank waste and Hanford tank waste SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE Hanford tank waste; simulant waste material; radioactive waste; organic acids ID CHROMATOGRAPHY-MASS-SPECTROMETRY AB Simulated Hanford tank waste samples were analyzed for organic acids before and after gamma-irradiation. Ion chromatography (IC) was used for the analysis for low-molecular-mass (LMM) organic acids and proved to be an improvement over the previously used non-suppressed IC with ultraviolet (UV) detection method. Known quantities of sodium salts of ethylenediaminetetraacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, citric acid and glycolic acid were added to the tank waste simulants before exposure. The breakdown products of gamma-irradiated simulated tank waste samples included formic, succinic and oxalic acids. These acids were identified and quantified using IC without any interference from nitrates, nitrites, or any other inorganic anions in the simulated waste. However, when non-suppressed IC with UV detection was used, nitrates and nitrites were found to interfere with the quantification of LMM organic acids. Ion chromatography techniques were also used on actual Hanford tank waste to quantify and analyze LMM organic acids. These efforts will assist in understanding Hanford tank waste chemistry and improving the carbon balance of tank waste samples. (C) 1998 Elsevier Science B.V. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Sharma, AK (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 18 TC 15 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 1 PY 1998 VL 805 IS 1-2 BP 101 EP 107 DI 10.1016/S0021-9673(98)00038-7 PG 7 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZP037 UT WOS:000073710200010 ER PT J AU Sengupta, S Boyle, JS AF Sengupta, S Boyle, JS TI Using common principal components for comparing GCM simulations SO JOURNAL OF CLIMATE LA English DT Article ID MODELS AB The technique of common principal components (CPC) is applied to compare the results of a number of GCM simulations. The data used are the 120 monthly mean fields from 30 Atmospheric Model Intercomparison Project (AMIP) simulations and an ensemble of five AMIP integrations from a single GCM. The spatial grid and 120 time points allows the calculation of up to 31 covariance matrices for input into the CPC analyses. The CPC methodology is applied to a variety of model comparision problems within the context of the AMIP experiment. The aspects of the simulations used for demonstration are the seasonal cycle of precipitation over the United States, the global 200-hPa velocity potential, and the difference between the 200-hPa divergence of four closely related AMIP models and the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis and a small ensemble of simulations (five) of the European Centre for Medium-Range Weather Forecasts AMIP model. These analyses demonstrate the utility of the CPC approach in identifying models systematic errors, the reduction of data in ensembles of simulation, and in model parameterization comparisons. The common errors among the models tend to highlight the area in which a gap in knowledge or parameterization implementation exists. In addition CPC analyses provide a more complete statistical picture of an emsemble of simulations within a single model than the traditional means and variances. It is often the common aspects of the ensembles that are sought as a robust signal. The CPC analyses tend to support the observation that the models often have more in common with each other than with the observations. The CPC has the ability to answer many pertinent questions posed in the arena of model comparison when used in conjunction with ether techniques. C1 Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. RP Boyle, JS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Mail Stop L-264,POB 808, Livermore, CA 94550 USA. NR 15 TC 13 Z9 14 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1998 VL 11 IS 5 BP 816 EP 830 DI 10.1175/1520-0442(1998)011<0816:UCPCFC>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP526 UT WOS:000073762300003 ER PT J AU Boyle, JS AF Boyle, JS TI Evaluation of the annual cycle of precipitation over the United States in GCMs: AMIP simulations SO JOURNAL OF CLIMATE LA English DT Article ID PROJECT; MODEL AB The monthly mean precipitation patterns of the Atmospheric Model Intercomparison Project decadal simulations over the United States and adjoining oceans are intercompared. A simple harmonic analysis of the 12-month seasonal mean precipitation values and a principal component (PC) analysis of the 120 monthly values were carried out. Emphasis is placed on the basic seasonal variation for three subregions: the eastern and central United States and the U.S. west coast. It is vital for GCM simulations to accurately portray the seasonal cycle. The results indicate the following. 1) There are problems for almost all the models in capturing the seasonal variation of the precipitation over the eastern United States. The models typically overemphasize the summer-spring rainfall amounts. The PC analysis indicates that many of the models tend to extend the precipitation regime typical of the central United States too far to the east, resulting in a precipitation maxima occurring in the summer for the eastern region. 2) The seasonal variation of the West Coast is handled with the greatest fidelity. This result cuts across all the models and may be attributable to the fact the SST forcing is specified and common to all the simulations. The common SST forcing is apparently a dominant factor in determining this region's precipitation climatology. 3) On the space scales of the regions selected, there is little consistent evidence that points to any specific model feature as a predictor of model performance. None of the obvious candidates such as horizontal resolution, convective closure schemes, or land surface schemes are reliable discriminators of a model's ability to simulate precipitation. 4) For one smaller subregion centered over Arizona, chosen because of the dominance of the semiannual cycle, there is evidence that increased horizontal resolution has an effect. For this intermountain region the higher-resolution models as a whole do better than the low-resolution models. However, even in this case there is enough variation among the individual simulations to obscure the conclusion that increased horizontal resolution is a necessary or sufficient quality to produce a reliable simulation. 5) The models tend to have less interannual variation than the observations with more variance being explained by the leading (annual cycle) PC, whereas the observations have a less peaked spectrum. C1 Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. RP Boyle, JS (reprint author), Univ Calif Lawrence Livermore Natl Lab, PCMDI, Mail Stop L-264,POB 808, Livermore, CA 94550 USA. NR 14 TC 29 Z9 30 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1998 VL 11 IS 5 BP 1041 EP 1055 DI 10.1175/1520-0442(1998)011<1041:EOTACO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP526 UT WOS:000073762300017 ER PT J AU Almgren, AS Bell, JB Colella, P Howell, LH Welcome, ML AF Almgren, AS Bell, JB Colella, P Howell, LH Welcome, ML TI A conservative adaptive projection method for the variable density incompressible Navier-Stokes equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE adaptive mesh refinement; incompressible flow; projection method ID MESH REFINEMENT; MIXING LAYERS; DYNAMICS; FLOW AB In this paper we present a method for solving the equations governing time-dependent, variable density incompressible flow in two or three dimensions on an adaptive hierarchy of grids. The method is based on a projection formulation in which we first solve advection-diffusion equations to predict intermediate velocities, and then project these velocities onto a space of approximately divergence-free vector fields. Our treatment of the first step uses a specialized second-order upwind method for differencing the nonlinear convection terms that provides a robust treatment of these terms suitable for inviscid and high Reynolds number flow. Density and other scalars are advected in such a way as to maintain conservation, if appropriate, and free-stream preservation. Our approach to adaptive refinement uses a nested hierarchy of logically-rectangular girds with simultaneous refinement of the girds in both space and time. The integration algorithm on the grid hierarchy is a recursive procedure in which coarse grids are advanced in time, fine grids are advanced multiple steps to reach the same time as the coarse grids and the data at different levels are then synchronized. The single grid algorithm is described briefly, but the emphasis here is on the time-stepping procedure for the adaptive hierarchy. Numerical examples are presented to demonstrate the algorithms's accuracy and convergence properties, and illustrate the behavior of the method. An additional example demonstrates the performance of the method on a more realistic problem, namely, a three-dimensional variable density shear layer. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Almgren, AS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 30 TC 245 Z9 249 U1 5 U2 27 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 1 PY 1998 VL 142 IS 1 BP 1 EP 46 DI 10.1006/jcph.1998.5890 PG 46 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZM888 UT WOS:000073586400001 ER PT J AU Moulton, JD Dendy, JE Hyman, JM AF Moulton, JD Dendy, JE Hyman, JM TI The black box multigrid numerical homogenization algorithm SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE porous media; permeability; numerical analysis; homogenization; multigrid ID HETEROGENEOUS POROUS-MEDIA; PERMEABILITY AB In mathematical models of flow through porous media, the coefficients typically exhibit severe variations in two or more significantly different length scales. Consequently, the numerical treatment of these problems relies on a homogenization or upscaling procedure to define an approximate coarse-scale problem that adequately captures the influence of the fine-scale structure. Inherent in such a procedure is a compromise between its computational cost and the accuracy of the resulting coarse-scale solution. Although techniques that balance the conflicting demands of accuracy and efficiency exist for a few specific classes of fine-scale structure (e.g., fine-scale periodic), this is not the case in general. In this paper we propose a new, efficient, numerical approach for the homogenization of the permeability in models of single-phase saturated flow. Our approach is motivated by the observation that multiple length scales are captured automatically by robust multilevel iterative solvers, such as Dendy's black box multigrid. In particular, the operator-induced variational coarsening in black box multigrid produces coarse-grid operators that capture the essential coarse-scale influence of the medium's fine-scale structure. We derive an explicit local, cell-based, approximate expression for the symmetric, 2 x 2 homogenized permeability tensor that is defined implicitly by the black box coarse-grid operator. The effectiveness of this black box multigrid numerical homogenization method is demonstrated through numerical examples. (C) 1998 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Moulton, JD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM moulton@lanl.gov NR 33 TC 46 Z9 47 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 1 PY 1998 VL 142 IS 1 BP 80 EP 108 DI 10.1006/jcph.1998.5911 PG 29 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZM888 UT WOS:000073586400004 ER PT J AU Strickland, JH Baty, RS AF Strickland, JH Baty, RS TI Modification of the carrier, Greengard, and Rokhlin FMM for independent source and target fields SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE fast multipole; vortex methods ID PARTICLE SIMULATIONS; ALGORITHM AB The Greengard-Rokhlin fast multipole method (FMM) provides an efficient numerical algorithm to calculate the two-dimensional stream function and velocity field at a number of target points associated with a large system of vortices (sources). In this paper we discuss an extension to their adaptive scheme. The added feature allows the specification of target points that do not have to coincide with the location of the sources. This is useful when specifying separate source and target fields for calculating boundary conditions, trajectories of passive scalar quantities, data for stream-function plots, etc. A simple algorithm has been developed to optimize the method for cases where the number of sources differs significantly from the number Of target points. (C) 1998 Academic Press. C1 Sandia Natl Labs, Engn Sci Ctr, Albuquerque, NM 87185 USA. RP Strickland, JH (reprint author), Sandia Natl Labs, Engn Sci Ctr, POB 5800, Albuquerque, NM 87185 USA. EM jhstric@sandia.gov; rsbaty@sandia.gov NR 4 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 1 PY 1998 VL 142 IS 1 BP 123 EP 128 DI 10.1006/jcph.1998.5907 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZM888 UT WOS:000073586400006 ER PT J AU Noell, AL Thompson, JL Corapcioglu, MY Triay, IR AF Noell, AL Thompson, JL Corapcioglu, MY Triay, IR TI The role of silica colloids on facilitated cesium transport through glass bead columns and modeling SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE silica colloids; cesium transport; colloid facilitated transport; glass bead columns; colloid modeling ID POROUS-MEDIA; PARTICLES; AQUIFER AB Groundwater colloids can act as a vector which enhances the migration of contaminants. While sorbed to mobile colloids, contaminants can be held in the aqueous phase which prevents them from interacting with immobile aquifer surfaces. In this study, an idealized laboratory set-up was used to examine the influence of amorphous silica colloids on the transport of cesium. Synthetic groundwater and saturated glass bead columns were used to minimize the presence of natural colloidal material. The columns were assembled in replicate, some packed with 150-210 mu m glass bead and others packed with 355-420 mu m glass beads. The colloids used in these experiments were 100 nm amorphous silica colloids from Nissan Chemical Company. In the absence of these colloids, the retardation factor for cesium was 8.0 in the 150-210 mu m glass bead columns and 3.6 in the 355-420 mu m glass bead columns. The influence of anthropogenic colloids was tested by injecting 0.09 pore volume slugs of an equilibrated suspension of cesium and colloids into the colloid-free columns. Although there was little noticeable facilitation in the smaller glass bead columns, there was a slight reduction in the retardation of cesium in the larger glass bead columns. This was attributed to cesium having less of a retention time in the larger glass bead columns. When cesium was injected into columns with a constant flux of colloids, the retardation of cesium was reduced by 14-32% in the 150-210 mu m glass bead columns and by 38-51% in the 355-420 mu m glass bead columns. A model based on Corapcioglu and Jiang (1993) [Corapcioglu, M.Y., Jiang, S., 1993. Colloid-facilitated groundwater contaminant transport, Water Resour. Res., 29 (7) 2215-2226] was compared with the experimental elution data. When equilibrium sorption expressions were used and the flux of colloids through the glass bead columns was constant, the colloid facilitated transport of cesium was able to be described using an effective retardation coefficient. Fully kinetic simulations, however, more accurately described the colloid facilitated transport of cesium. (C) 1998 Elsevier Science B.V. C1 Texas A&M Univ, Dept Civil Engn, College Stn, TX 77843 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Corapcioglu, MY (reprint author), Texas A&M Univ, Dept Civil Engn, College Stn, TX 77843 USA. NR 31 TC 40 Z9 40 U1 0 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1998 VL 31 IS 1-2 BP 23 EP 56 DI 10.1016/S0169-7722(97)00054-5 PG 34 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA ZQ197 UT WOS:000073832300002 ER PT J AU Park, J Barnes, PA Tin, CC Allerman, AA AF Park, J Barnes, PA Tin, CC Allerman, AA TI Lateral overgrowth and epitaxial lift-off of InP by halide vapor-phase epitaxy SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE halide VPE; lateral overgrowth; epitaxial lift-off; CLEFT ID DEPOSITION; FILMS; GAAS; GROWTH AB The orientation dependence of lateral overgrowth and vertical growth of InP deposits selectively grown through stripe openings in a phosphosilicate glass mask was investigated using halide vapor-phase epitaxy. The lateral overgrowth was observed to be strongly dependent on the orientation of stripe openings, and the vertical growth was shown to be inversely correlated to the lateral overgrowth. For a sufficiently long growth time, the growth fronts of lateral overgrowth layers from adjacent stripe openings merged together to form a completely overgrown layer. The morphology of the region where the growth fronts are merged was shown to be dependent on the orientation of stripe openings through which the growth was seeded. We also investigated a method to separate the completely overgrown layer from the substrate. This mechanical epitaxial lift-off technique may be used for hybrid integration of optoelectronic and electronic devices. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Auburn Univ, Auburn, AL 36849 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Park, J (reprint author), Univ Texas, Ctr Microelect Res, PRC-MER R9900, Austin, TX 78712 USA. RI Schaff, William/B-5839-2009; Tin, Chin-Che/A-9122-2012 NR 15 TC 7 Z9 7 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY PY 1998 VL 187 IS 2 BP 185 EP 193 DI 10.1016/S0022-0248(97)00870-1 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA ZH715 UT WOS:000073140400003 ER PT J AU Park, JS Trivedi, R AF Park, JS Trivedi, R TI Convection-induced novel oscillating microstructure formation in peritectic systems SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE oscillating microstructure; convection; peritectic; bands AB Critical experiments have been carried out to examine the formation of banded microstructures in the peritectic Sn-Cd system in both diffusive and convective regimes. It is shown that in directional solidification studies by a conventional method in 3-6 mm diameter tubes, a new oscillatory structure forms which is induced by convection. In this oscillatory mode the two phases form an interconnected network which appear as bands only on specific cross-sections. A successive sectioning has revealed that this microstructure consists of a large tree-like structure of the primary phase that is surrounded by the peritectic phase. A new experimental technique is developed to obtain diffusive growth by directionally solidifying in very thin samples. As the diameter of the sample was reduced, convection effects were reduced and the oscillatory structure was found to disappear for compositions in the hyperperitectic region. Only in the hypoperitectic composition range, where band formation is predicted by the diffusive model, discrete bands have been observed to form in thin samples of diameter 0.6 mm or less. (C) 1998 Elsevier Science B.V. All rights reserved. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Trivedi, R (reprint author), US DOE, Ames Lab, 100 Wilhelm Hall, Ames, IA 50011 USA. EM trivedi@ameslab.gov NR 9 TC 53 Z9 57 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY PY 1998 VL 187 IS 3-4 BP 511 EP 515 DI 10.1016/S0022-0248(97)00884-1 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA ZP043 UT WOS:000073710800026 ER PT J AU Brookes, NB Sinkovic, B Tjeng, LH Goedkoop, JB Hesper, R Pellegrin, E de Groot, FMF Altieri, S Hulbert, SL Shekel, E Sawatzky, GA AF Brookes, NB Sinkovic, B Tjeng, LH Goedkoop, JB Hesper, R Pellegrin, E de Groot, FMF Altieri, S Hulbert, SL Shekel, E Sawatzky, GA TI Study of magnetism using circularly polarized soft X-rays SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE CuO; resonant process; soft-X-ray photoemission; MCD; spin-resolved; nickel metal ID RESONANT PHOTOEMISSION; ELECTRONIC-STRUCTURE; NICKEL; TEMPERATURE; TRANSITION; DICHROISM; SATELLITE; BANDS; CUO AB It has recently been shown that spin-resolved valence band photoemission spectra can be obtained from macroscopically non-magnetic transition metal materials. This is achieved by combining circularly polarized soft X-rays, electron spin detection and 2P(3/2) (L-3) resonant photoemission. These experiments have been performed at the European Synchrotron Radiation Facility (ESRF) by combining a helical undulator, HELIOS I, a 'Dragon' spherical grating monochromator and the New York University (NYU) spin-resolved spectrometer, specifically designed for soft-X-ray photoemission experiments. Examples will be given of applications to antiferromagnetic materials (e.g. CuO) and paramagnets (e.g. nickel metal above its Curie temperature). (C) 1998 Elsevier Science B.V. All rights reserved. C1 European Synchrotron Radiat Facil, F-38043 Grenoble, France. NYU, Dept Phys, New York, NY 10003 USA. Univ Groningen, Ctr Mat Sci, Solid State Phys Lab, NL-9747 AG Groningen, Netherlands. Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. RP Brookes, NB (reprint author), European Synchrotron Radiat Facil, BP 220, F-38043 Grenoble, France. RI de Groot, Frank/A-1918-2009; Sawatzky, George/D-2997-2012 NR 25 TC 11 Z9 11 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 11 EP 18 DI 10.1016/S0368-2048(98)00092-9 PG 8 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400005 ER PT J AU Fedorov, AV Valla, T Huang, DJ Reisfeld, G Loeb, F Liu, F Johnson, PD AF Fedorov, AV Valla, T Huang, DJ Reisfeld, G Loeb, F Liu, F Johnson, PD TI Spin polarized photoemission studies of the Gd(0001) surface SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE gadolinium; magnetic properties; photoemission ID ANGLE-RESOLVED PHOTOEMISSION; CURIE-TEMPERATURE; GADOLINIUM; ORDER; STATE; BULK AB The surface magnetic properties of the rare earth Lanthanide, gadolinium (Gd) have been the subject of a number of different experimental and theoretical studies in recent years. These studies have suggested that the surface of Gd exhibits a variety of unusual magnetic properties including imperfect ferromagnetic coupling between the surface and bulk, canted magnetic moments and some form of phase transition. Also the temperature dependent behavior appears to be quite controversial with both a Stoner-like and spin-mixing behavior invoked to describe the loss of magnetization. With new angle- and spin-resolved studies carried out at room and low temperatures, we re-examine this temperature dependence and confirm that both types of behavior are evident. We further provide direct evidence that at the temperature of liquid nitrogen, it is possible to observe a canting of the surface moments out of the surface plane. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Fedorov, AV (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 21 TC 8 Z9 8 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 19 EP 24 DI 10.1016/S0368-2048(98)00093-0 PG 6 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400006 ER PT J AU Gog, T Eisenhower, RA Menk, RH Tegze, M LeDuc, G AF Gog, T Eisenhower, RA Menk, RH Tegze, M LeDuc, G TI Multiple-energy X-ray holography with atomic resolution SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE X-ray holography; electron holography ID DIFFRACTION PATTERNS; PHOTOELECTRON HOLOGRAPHY; ELECTRON; SCATTERING; IMAGES AB Recent approaches to achieving atomic resolution with holographic methods and directly image atomic structures in the bulk at surfaces and interfaces of solids have become increasingly successful. Multiple-energy X-ray holography (MEXH), a particular implementation of such a method, is reviewed and its first applications to bulk crystals and nano-clusters suspended in a crystalline matrix is presented. MEXH utilizes X-rays to generate an interference field within the sample, then determines its strength at specific atomic sites from fluorescence emissions. Scanning reciprocal space, a hologram is recorded from which local atomic structures can be reconstructed by Fourier transformation. Image aberrations known to distort single-energy holograms are effectively suppressed in this novel multi-energy technique. (C) 1998 Elsevier Science B,V. All rights reserved. C1 Argonne Natl Lab, CMC CAT Adv Photon Source, Argonne, IL 60439 USA. Sincrotrone Trieste, I-34012 Trieste, Italy. DESY, Hamburger Synchrotronstrahlungslab Hasylab, D-22603 Hamburg, Germany. Hungarian Acad Sci, Solid State Phys Res Inst, H-1525 Budapest, Hungary. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Gog, T (reprint author), Argonne Natl Lab, CMC CAT Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 23 TC 13 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 123 EP 129 DI 10.1016/S0368-2048(98)00113-3 PG 7 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400026 ER PT J AU Jia, JJ Callcott, TA Ederer, DL Perera, RCC AF Jia, JJ Callcott, TA Ederer, DL Perera, RCC TI Inelastic scattering energy loss in CaF2 observed with soft X-ray fluorescence spectroscopy SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE inelastic scattering; energy loss in CaF2; soft X-ray fluorescence spectroscopy ID EMISSION; STATES AB The advent of third-generation synchrotron radiation sources has stimulated interest in the study of X-ray emission using photon excitation. Soft X-ray fluorescence (SXF) provides a means of measuring the element and angular momentum selective valence band density of states in complex materials. Tenability of the excitation source allows a detailed investigation of the dynamical behavior of the relaxation channels and the coupling between the excitation and emission process that occurs near a resonance or an absorption edge. As an example of resonant inelastic scattering studies in solid systems by SXF spectroscopy at the insertion device beam line BL 8.0 at ALS, results from CaF2 will be presented. When the energy of exciting photons is tuned to the Ca 2p-3d threshold absorption peak in CaF2, the SXF produced by recombination of the excited electrons with core holes exhibits remarkable resonances for both the 2p(3/2) and 2p(1/2) levels. When the resonant 2p-3d SXF peaks are excited, additional broad peaks appear in the spectra below the normal valence band spectrum, which are displaced from the resonant peaks by about 17 eV and track the changes in excitation energy. We identify this as evidence of a coherent, inelastic scattering process, analogous to resonant Raman scattering, in which incident photons excite a localized electronic transition and are reradiated at an energy reduced by the energy of the excitation. Evidence is also presented which indicates that the 2p-3d absorption transitions lie about 1 eV above a weak Ca 4s absorption threshold. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Jia, JJ (reprint author), Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. NR 13 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 181 EP 187 DI 10.1016/S0368-2048(98)00120-0 PG 7 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400033 ER PT J AU Shin, S Fujisawa, M Ishii, H Harada, Y Watanabe, M Grush, MM Callcott, TA Perera, RCC Kurmaev, EZ Moewes, A Winarski, R Stadler, S Ederer, DL AF Shin, S Fujisawa, M Ishii, H Harada, Y Watanabe, M Grush, MM Callcott, TA Perera, RCC Kurmaev, EZ Moewes, A Winarski, R Stadler, S Ederer, DL TI Soft X-ray emission spectroscopy of early transition metal compounds SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE transition metal compounds; fluorescence; Raman scattering ID PHOTOEMISSION; TI AB Soft X-ray emission studies for several early transition metal compounds, such as Sc, Ti and V compounds, have been studied. Raman scattering was found at the 2p --> 3d excitation in the transition metal compounds. The elementary excitation of the Raman spectrum is mainly elucidated by the d-d transition within the 3d bands, as well as the interband transition from the O 2p valence band to the conduction band, which consists mainly of transition metal 3d states. The charge transfer transition due to the localized electron picture is dominant in the soft X-ray spectra of Sc compounds. Raman scattering is a powerful tool in the study of the electronic structure of transition metal compounds. (C) 1998 Elsevier Science B,V. All rights reserved. C1 Univ Tokyo, Inst Solid State Phys, Synchrotron Radiat Lab, Tokyo 188, Japan. KEK, Tsukuba, Ibaraki 305, Japan. Univ Tennessee, Knoxville, TN 37996 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, ALS, Berkeley, CA 94720 USA. Inst Phys Met, Ekaterinburg 620219, Russia. CAMD, Baton Rouge, LA 70803 USA. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. RP Shin, S (reprint author), Univ Tokyo, Inst Solid State Phys, Synchrotron Radiat Lab, 3-2-1 Midoricho, Tokyo 188, Japan. RI Kurmaev, Ernst/J-4254-2013 OI Kurmaev, Ernst/0000-0003-4625-4930 NR 14 TC 28 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 197 EP 205 DI 10.1016/S0368-2048(98)00122-4 PG 9 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400035 ER PT J AU Grush, MM Muramatsu, Y Underwood, JH Gullikson, EM Ederer, DL Perera, RCC Callcott, TA AF Grush, MM Muramatsu, Y Underwood, JH Gullikson, EM Ederer, DL Perera, RCC Callcott, TA TI Soft X-ray emission and absorption - a comparative study on the sensitivity to oxidation state and ligand environment of transition metal complexes SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE soft X-ray fluorescence; soft X-ray absorption; manganese; transition metals ID SPECTROSCOPY; SYSTEM AB In order to understand the function of transition metals, which are a necessary part of many catalytic cycles, it is necessary to obtain information about oxidation states, ligand environment, and local structure surrounding the metal centers. L-Edge Xray absorption spectroscopy, which probes the unoccupied 3d levels, has been shown to be a sensitive probe of the oxidation and spin state of transition metal sites. As soft X-ray fluorescence (SXF) instead probes the occupied states, an investigation of how this complementary technique can be used to probe transition metal centers was conducted and the results are presented here. SXF is found to be very sensitive to ligand environment and relatively insensitive to electronic geometry and metal oxidation state. Potential applications of this technique to systems such as metalloproteins and manganese-lithium batteries are discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Knoxville, TN 37996 USA. NTT Corp, Integrated Informat & Energy Syst Lab, Tokyo 180, Japan. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tulane Univ, New Orleans, LA 70118 USA. RP Grush, MM (reprint author), Univ Tennessee, Knoxville, TN 37996 USA. NR 11 TC 12 Z9 12 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 EI 1873-2526 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 225 EP 229 DI 10.1016/S0368-2048(98)00126-1 PG 5 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400039 ER PT J AU Underwood, JH Gullikson, EM AF Underwood, JH Gullikson, EM TI High-resolution, high-flux, user friendly VLS beamline at the ALS for the 50-1300 eV energy region SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE Advanced Light Source; synchrotron radiation source; VLS monochromator; soft X-rays AB We describe a bending magnet beamline designed to operate on a third generation synchrotron light source-the Advanced Light Source (ALS)-in the energy range 50-1300 eV. It was constructed for the characterization of optical elements (mirrors, gratings, multilayers, detectors, etc.) but has capabilities for a wide range of measurements in other fields, in particular materials science and atomic physics. The optical system consists of a monochromator, a reflectometer, a three-mirror order suppressor, and horizontal and vertical focusing mirrors to provide a small spot on the sample. The monochromator is a varied line spacing, plane grating (VLS-PGM) design in which the mechanically ruled grating operates in the converging light from a spherical minor working at high demagnification. The spherical aberration of this mirror is corrected by the grating line spacing variation, so that the monochromator is essentially aberration-free over its tuning range. Wavelength is scanned by simple rotation of the grating with a fixed exit slit. The small size and stability of the ALS source allows entrance slitless operation, leading to high flux and a spectral resolving power lambda/Delta lambda of around 7000, limited by the ALS vertical source size. The reflectometer has the capability of positioning the sample to 10 mu m and setting its angular position to 0.002 degrees. LABVIEW(TM)-based software provides a convenient interface to the user. The reflectometer is separated from the beamline by a differential pump, and can be pumped down to 10(-7) ton, in 0.5 h. This allows rapid turn-around of materials science samples for measurements which do not require UHV, such as NEXAFS. Auxiliary experimental stations can be mounted behind the reflectometer. Results are shown which demonstrate the performance and operational convenience of the beamline. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Lawrence Livermore Natl Lab, Ctr Xray Opt, Lawrence, CA 94550 USA. RP Underwood, JH (reprint author), Lawrence Livermore Natl Lab, Ctr Xray Opt, Lawrence, CA 94550 USA. NR 6 TC 123 Z9 123 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 265 EP 272 DI 10.1016/S0368-2048(98)00134-0 PG 8 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400047 ER PT J AU Sasaki, S Nakamura, N Kamiya, Y Yokoyama, M Kawai, M Kobayashi, H Kakuno, K AF Sasaki, S Nakamura, N Kamiya, Y Yokoyama, M Kawai, M Kobayashi, H Kakuno, K TI Insertion devices for VSX ring SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Todai Symposium / 6th ISSP International Symposium on Frontiers in Synchrotron Radiation Spectroscopy CY OCT 27-30, 1997 CL UNIV TOKYO, INST SOLID STATE PHYS, TOKYO, JAPAN HO UNIV TOKYO, INST SOLID STATE PHYS DE insertion device; undulator; linear polarization; circular polarization; harmonics; VUV; X-ray ID UNDULATOR AB A new low emittance storage ring for VUV and soft X-ray brilliant light source is planned for construction in the Kashiwa Campus of the University of Tokyo. This ring has long straight sections as well as standard insertion device straight sections. Multiple insertion devices of various kinds can provide a wide range of photon energy spectra. By installing a 10 m long insertion device into a long straight section, for example, one can obtain a brilliance exceeding 10(20) phs s(-1) mrad(-2) mm(-2) 0.1% b.w.(-1) We can use higher harmonics of undulator radiation having both linear and circular polarization properties. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 106, Japan. Kawasaki Heavy Ind Ltd, Kanto Tech Inst, Noda, Chiba 278, Japan. Shin Etsu Chem Co, Magnet Mat R&D Ctr, Fukui 915, Japan. RP Sasaki, S (reprint author), Sincrotrone Trieste, Strada Statale 14,Km 163-5,Area Sci Pk, I-34012 Trieste, Italy. NR 8 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 1998 VL 92 IS 1-3 BP 315 EP 319 DI 10.1016/S0368-2048(98)00140-6 PG 5 WC Spectroscopy SC Spectroscopy GA ZY125 UT WOS:000074555400053 ER PT J AU Rouvimov, S Liliental-Weber, Z Swider, W Washburn, J Weber, ER Sasaki, A Wakahara, A Furkawa, Y Abe, T Noda, S AF Rouvimov, S Liliental-Weber, Z Swider, W Washburn, J Weber, ER Sasaki, A Wakahara, A Furkawa, Y Abe, T Noda, S TI Effects of GaAs-spacer strain on vertical ordering of stacked InAs quantum dots in a GaAs matrix SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE InAs/GaAs; quantum dots; strain; vertical ordering ID SELF-ORGANIZATION; GROWTH; ISLANDS; SUPERLATTICES AB Vertical ordering in stacked layers of InAs/GaAs quantum dots is currently the focus of scientific research because of its potential for optoelectronics applications. Transmission electron microscopy was applied to study InAs/GaAs stacked layers grown by molecular-beam-epitaxy with various thicknesses of GaAs spacer. Thickness dependencies of quantum dot size and their ordering were observed experimentally and, then, compared with the results of strain calculations based on the finite element method. The vertical ordering did occur when the thickness of the GaAs spacer was comparable with the dot height. The ordering was found to be associated with relatively large InAs dots on the first layer. Quantum dots tend to become larger in size and more regular in plane with increasing numbers of stacks. Our results suggest that the vertical ordering is not only affected by strain from the InAs dots on the lower layer, but by total strain configuration in the multi-stacked structure. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Kyoto Univ, Kyoto 60601, Japan. Osaka Electrocommun Univ, Neyagawa, Osaka 570, Japan. RP Rouvimov, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 15 TC 33 Z9 33 U1 0 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1998 VL 27 IS 5 BP 427 EP 432 DI 10.1007/s11664-998-0172-6 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA ZN091 UT WOS:000073608700007 ER PT J AU Schulz, DL Curtis, CJ Flitton, RA Wiesner, H Keane, J Matson, RJ Jones, KM Parilla, PA Noufi, R Ginley, DS AF Schulz, DL Curtis, CJ Flitton, RA Wiesner, H Keane, J Matson, RJ Jones, KM Parilla, PA Noufi, R Ginley, DS TI Cu-In-Ga-Se nanoparticle colloids as spray deposition precursors for Cu(In,Ga)Se-2 solar cell materials SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE CuInSe2; CIS; colloid; nanoparticle; solar cell; spray deposition ID FILMS; CUINSE2; GROWTH AB The use of nanoparticle colloids for spray deposition of Cu(In,Ga)Se-2 (CIGS) precursor films and subsequent fabrication of CIGS solar cells has been investigated. According to this approach, amorphous Cu-In-Ga-Se nanoparticle colloids were first prepared by reacting a mixture of CuI, InI3, and GaI3 in pyridine with Na2Se in methanol at reduced temperature. Purified colloid was sprayed onto heated molybdenum-coated sodalime glass substrates to form Cu-In-Ga-Se precursor films. After thermal processing of the precursor films under a selenium ambient, CIGS solar cells were fabricated. Cu-In-Ga-Se colloids and films were characterized by inductively coupled plasma atomic emission spectroscopy, thermogravimetric analysis; transmission electron microscopy, x-ray diffraction, scanning electron microscopy, and Auger electron spectroscopy. Standard current-voltage characterization was performed on the CIGS solar cell devices with the best film exhibiting a solar conversion efficiency of 4.6%. C1 Natl Renewable Energy Lab, Ctr Photovoltaic & Elect Mat, Golden, CO 80401 USA. RP Schulz, DL (reprint author), Natl Renewable Energy Lab, Ctr Photovoltaic & Elect Mat, 1617 Cole Blvd, Golden, CO 80401 USA. NR 12 TC 64 Z9 65 U1 5 U2 30 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1998 VL 27 IS 5 BP 433 EP 437 DI 10.1007/s11664-998-0173-5 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA ZN091 UT WOS:000073608700008 ER PT J AU Schmieman, EA Yonge, DR Rege, MA Petersen, JN Turick, CE Johnstone, DL Apel, WA AF Schmieman, EA Yonge, DR Rege, MA Petersen, JN Turick, CE Johnstone, DL Apel, WA TI Comparative kinetics of bacterial reduction of chromium SO JOURNAL OF ENVIRONMENTAL ENGINEERING LA English DT Article ID ENTEROBACTER-CLOACAE STRAIN; HEXAVALENT-CHROMIUM; ANAEROBIC CONDITIONS; BIOREACTOR SYSTEM; CHROMATE; REMOVAL AB Most previous studies of bacterial reduction of chromium have been done with pure cultures that are not likely to be found in ground water, and at hexavalent chromium concentrations much greater than typically present in contaminated ground water. Further, most previous work has been performed with complex laboratory substrates that would not be suitable for in situ application. In this study, mixed cultures were enriched from three diverse soil sources: surface soil, subsurface soil, and river sediment. The enrichment medium contained 10 mg Cr6+/L and sucrose as the carbon source. The three mixed cultures obtained from the diverse soil samples were transferred to batch reactors and exhibited similar chromium reduction enzyme kinetics at stationary phase. The maximum specific reduction rates were between 0.98 and 3.3 mg Cr6+/(g dry cells.h) and the half velocity constants were between 0.39 and 1.48 mg Cr6+/L. The relatively narrow range of values for kinetic parameters suggests that a conservative engineering design for in situ remediation could be applied over a wide range of contaminated sites at the Cr(VI) concentrations examined. C1 Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA. Washington State Univ, Ctr Multiphase Environm Res, Pullman, WA 99164 USA. Idaho Natl Lab, Dept Biotechnol, Idaho Falls, ID 83415 USA. RP Schmieman, EA (reprint author), Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA. EM yonge@wsu.edu RI Petersen, James/B-8924-2008 NR 40 TC 53 Z9 54 U1 1 U2 11 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0733-9372 EI 1943-7870 J9 J ENVIRON ENG JI J. Environ. Eng.-ASCE PD MAY PY 1998 VL 124 IS 5 BP 449 EP 455 DI 10.1061/(ASCE)0733-9372(1998)124:5(449) PG 7 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZJ416 UT WOS:000073213300008 ER PT J AU Shafique, MSB Walton, JC Gutierrez, N Smith, RW Tarquin, AJ AF Shafique, MSB Walton, JC Gutierrez, N Smith, RW Tarquin, AJ TI Influence of carbonation on leaching of cementitious wasteforms SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID WATER AB The presented work represents a combined experimental and modeling approach to evaluate the role of carbon dioxide in the long-term performance of cementitious wasteforms. Small wasteforms were cast with Portland cement and synthetic wastewater containing known amounts of dissolved metals and nitrate as a tracer. A series of wasteforms was exposed to a control (CO2-free) and an accelerated environment for carbonation (50% CO2). The samples were subjected to dynamic leaching tests, and the results were fit to the two-dimensional diffusional release equation. Comparison of results for carbonated and noncarbonated samples indicated that both physical and chemical properties controlling release were altered by carbonation. Carbonation slowed the diffusional release of strontium and increased the release of nitrate, calcium, cadmium, lead, and cobalt. Comparison of the leaching rate of each metal relative to calcium was used to indicate solid solution in calcium hydroxide (cadmium) and calcium carbonate (cadmium and strontium). Leaching of cadmium and strontium appears to be heavily influenced by solid solution in calcium bearing phases. C1 Univ Texas, Dept Civil Engn, El Paso, TX 79968 USA. Idaho Natl Engn Lab, Dept Biotechnol, Idaho Falls, ID USA. RP Walton, JC (reprint author), Univ Texas, Dept Civil Engn, El Paso, TX 79968 USA. EM jwalton@cs.utep.edu NR 24 TC 10 Z9 11 U1 1 U2 3 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD MAY PY 1998 VL 124 IS 5 BP 463 EP 467 DI 10.1061/(ASCE)0733-9372(1998)124:5(463) PG 5 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZJ416 UT WOS:000073213300010 ER PT J AU Webb, SW AF Webb, SW TI Capillary barriers and Subtitle D covers: Estimating equivalency - Discussion SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Editorial Material C1 Sandia Natl Labs, Environm Restorat Technol Dept, Albuquerque, NM 87185 USA. RP Webb, SW (reprint author), Sandia Natl Labs, Environm Restorat Technol Dept, Albuquerque, NM 87185 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD MAY PY 1998 VL 124 IS 5 BP 483 EP 483 DI 10.1061/(ASCE)0733-9372(1998)124:5(483) PG 1 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZJ416 UT WOS:000073213300018 ER PT J AU Grant, PM Moody, KJ Hutcheon, ID Phinney, DL Haas, JS Volpe, AM Oldani, JJ Whipple, RE Stoyer, N Alcaraz, A Andrews, JE Russo, RE Klunder, GL Andresen, BD Cantlin, S AF Grant, PM Moody, KJ Hutcheon, ID Phinney, DL Haas, JS Volpe, AM Oldani, JJ Whipple, RE Stoyer, N Alcaraz, A Andrews, JE Russo, RE Klunder, GL Andresen, BD Cantlin, S TI Forensic analyses of suspect illicit nuclear material SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; illicit nuclear materials; nuclear smuggling; nuclear forensic analyses and characterization ID PROLIFERATION AB A small metal sample, alleged to be a substance that could substitute for highly enriched uranium in a nuclear weapon, was subjected to qualitative and quantitative forensic analyses using methods of materials science, radioisotopic chemistry, inorganic chemistry, and organic chemistry. The specimen was determined to be moderately pure Sc, likely derived from a uranium refining operation. Although no fissionable species or weaponization signatures were detected, the sample did exhibit some unusual properties. These anomalies included lanthanide fractionation, with concentrations of Dy, Ho, and Er elevated by factors greater than 100 over normal levels, and the presence of long, odd-chain fatty acids. C1 Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, Livermore, CA 94550 USA. RP Grant, PM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, L-178, Livermore, CA 94550 USA. NR 21 TC 5 Z9 6 U1 0 U2 15 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD MAY PY 1998 VL 43 IS 3 BP 680 EP 688 PG 9 WC Medicine, Legal SC Legal Medicine GA ZN879 UT WOS:000073692700033 ER PT J AU Sergeev, VA Shukhtina, MA Rasinkangas, R Korth, A Reeves, GD Singer, HJ Thomsen, MF Vagina, LI AF Sergeev, VA Shukhtina, MA Rasinkangas, R Korth, A Reeves, GD Singer, HJ Thomsen, MF Vagina, LI TI Event study of deep energetic particle injections during substorm SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PROTON DRIFT ECHOES; GEOSYNCHRONOUS ORBIT; INNER MAGNETOSPHERE; SYNCHRONOUS ORBIT; MAGNETIC-FIELD; CURRENT WEDGE; GROWTH-PHASE; DYNAMICS; ONSET; CRRES AB The origin of multiple energetic particle injections into the inner magnetosphere is addressed using a rare opportunity of measuring the energetic particle fluxes at different radial distances under known electric and magnetic fields. During a strong substorm on February 10, 1991, the CRRES spacecraft measured E and B fields and high-energy particle fluxes near the magnetic equator at r similar to 5 R-e, whereas particle injections, their azimuthal locations, and some other parameters were simultaneously monitored by three geostationary spacecraft and ground networks. We show a multitude of impulsive short-duration injection events which correlate with 1-2 min long pulses of dawn-dusk electric field. The observations suggest that some E field pulses recorded deep in the inner magnetosphere were fast magnetosonic waves radiated by the current disruption region. This supports the concept of impulsive dissipation event as an elementary building block of substorm expansion. Furthermore, our modeling results indicate that most of the flux variations of energetic particles can be explained by the global convective transport and corresponding particle acceleration. However, we emphasize that, depending on particle spectra and radial flux gradient, one can observe either flux increase, or decrease, or no variation (often seen in different energy ranges simultaneously and at the same point) as a response to the electric field pulse. Both the cloud of injected particles and magnetic field dipolarization region had a sharp inner boundary (injection front) which propagated inward at the convection speed. We document the complicated structure of this front, consisting of a diamagnetic hot proton layer followed by the dipolarixation front which contains enhanced energetic electron fluxes. Further study is required to understand hom common this structure is and, if common, how it may be formed. C1 St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Oulu, Dept Phys Sci, FIN-90571 Oulu, Finland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Sergeev, VA (reprint author), St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. RI Shukhtina, Maria/K-3783-2013; Reeves, Geoffrey/E-8101-2011; Sergeev, Victor/H-1173-2013 OI Shukhtina, Maria/0000-0001-7892-8392; Reeves, Geoffrey/0000-0002-7985-8098; Sergeev, Victor/0000-0002-4569-9631 NR 54 TC 42 Z9 43 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1998 VL 103 IS A5 BP 9217 EP 9234 DI 10.1029/97JA03686 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL412 UT WOS:000073430300013 ER PT J AU Birn, J Thomsen, MF Borovsky, JE Reeves, GD McComas, DJ Belian, RD Hesse, M AF Birn, J Thomsen, MF Borovsky, JE Reeves, GD McComas, DJ Belian, RD Hesse, M TI Substorm electron injections: Geosynchronous observations and test particle simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CURRENT DISRUPTION; ION; ACCELERATION; REGION AB We investigate electron acceleration and the flux increases associated with energetic electron injections on the basis of geosynchronous observations and test-electron orbits in the dynamic fields of a three-dimensional MHD simulation of neutral line formation and dipolarization in the magnetotail. This complements an earlier investigation of test protons [Birn et al., 1997b]. In the present paper we consider equatorial orbits only, using the gyrocenter drift approximation. It turns out that this approximation is valid for electrons prior to and during the flux rises observed in the near tail region of the model at all energies considered (similar to 100 eV to 1 MeV). The test particle model reproduces major observed characteristics: a fast flux rise, comparable to that of the ions, and the existence of five categories of dispersionless events, typical for observations at different local times. They consist of dispersionless injections of ions or electrons without accompanying injections of the other species, delayed electron injections and delayed ion injections, and simultaneous two-species injections. As postulated from observations [Birn et al., 1997a], these categories can be attributed to a dawn-dusk displacement of the ion and electron injection boundaries in combination with an earthward motion or expansion. The simulated electron injection region extends farther toward dusk at lower energies (say, below 40 keV) than at higher energies. This explains the existence of observed energetic ion injections that are accompanied by electron flux increases at the lower energies but not by an energetic electron injection at energies above 50 keV. The simulated distributions show that flux increases are limited in energy, as observed. The reason for this limitation and for the differences between the injection regions at different energies is the localization in the dawn-dusk direction of the tail collapse and the associated cross-tail electric field, in combination with a difference in the relative importance of E x B drift and gradient drifts at different energies. The results demonstrate that the collapsing field region earthward of the neutral line appears to be more significant than the neutral line itself for the acceleration of electrons, particularly for the initial rise of the fluxes and the injection boundary. This is similar to the result obtained for test ions [Birn et al., 1997b]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. RP Birn, J (reprint author), Univ Calif Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov; mthomsen@lanl.gov; jborovsky@lanl.gov; gdreeves@lanl.gov; dmccomas@lanl.gov; rdbelian@lanl.gov; hesse@gsfc.nasa.gov RI Hesse, Michael/D-2031-2012; Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 22 TC 106 Z9 106 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1998 VL 103 IS A5 BP 9235 EP 9248 DI 10.1029/97JA02635 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL412 UT WOS:000073430300014 ER PT J AU Newbury, JA Russell, CT Phillips, JL Gary, SP AF Newbury, JA Russell, CT Phillips, JL Gary, SP TI Electron temperature in the ambient solar wind: Typical properties and a lower bound at 1 AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA-EXPERIMENT; MAGNETIC-FIELD; HEAT-FLUX; ULYSSES OBSERVATIONS; MACH NUMBER; SHOCK; DISTRIBUTIONS; ISEE-3; SPEED; WAVES AB Our understanding of what controls the solar wind electron temperature is far from complete. Previous studies from the Vela and IMP spacecraft have suggested that twice the proton temperature or an assumed average of similar to 150,000 K are reasonable estimations of total electron temperature at 1 AU. Eighteen months of continuous ISEE 3 solar wind data are analyzed in this paper and are found to have a mean electron temperature of 141,000 +/- 38,000 K, in good agreement with past measurements. No correlation is found between electron temperature and other solar wind parameters, including proton temperature. However, a very distinct lower bound on the electron temperature is found; this bound increases with proton temperature and is observed by both ISEE 3 and Ulysses spacecraft. The bound is also found to vary with bulk solar speed of the solar wind and with distance from the Sun. Solar wind plasma observed following stream interactions are often associated with temperatures near this bound, and enhanced electromagnetic wave activity in the 18-100 Hz range is coincident with intervals where this apparent temperature coupling is observed, suggesting the possible presence of wave-particle interactions. Possible explanations for the existence of this electron temperature bound are explored, but no definitive answer has been found at this time. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Grp NIS 1, Los Alamos, NM 87545 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. RP Newbury, JA (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 405 Hilgard Ave, Los Angeles, CA 90095 USA. NR 40 TC 67 Z9 67 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1998 VL 103 IS A5 BP 9553 EP 9566 DI 10.1029/98JA00067 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL412 UT WOS:000073430300044 ER PT J AU Nelson, RA Bejan, A AF Nelson, RA Bejan, A TI Constructal optimization of internal flow geometry in convection SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE natural convection; porous media; thermodynamics and second law ID NATURAL-CONVECTION; HEAT-TRANSFER AB In this paper "constructal theory" is used to predict the formation of geometric shape and structure in finite-size fluid systems subjected to heating from below. Two classes of system are considered as tests: (i) single-phase fluid layers, and (ii) porous layers saturated with single-phase fluids. It is shown that the minimization of thermal resistance across the layer can be used to account for the appearance of organized macroscopic motion (streams) on the background of disorganized motion (diffusion). By optimizing the shape of the flow, it is possible to predict analytically the main structural and hear transfer characteristics of the system, e.g., the onset of convection, the relation between Nusselt number and Rayleigh number, the geometric shape of the rolls, and the decreasing exponent of Ra-H as Ra-H increases. The convective flow structure emerges as the result of a process of geometric optimization of heat flow path, in which diffusion is assigned to length scales smaller than the smallest macroscopic flow element (elemental system). The implications of this test of constructal theory are discussed in the context of the wider search for a physics law of geometric geometric form generation in natural flow systems. C1 Univ Calif Los Alamos Natl Lab, Technol & Safety Assessment Div, Nucl Syst & Design Anal Grp, Los Alamos, NM 87545 USA. Duke Univ, Dept Mech Engn & Mat Sci, Durham, NC 27708 USA. RP Nelson, RA (reprint author), Univ Calif Los Alamos Natl Lab, Technol & Safety Assessment Div, Nucl Syst & Design Anal Grp, MS K575, Los Alamos, NM 87545 USA. RI Bejan, Adrian/D-3909-2012 NR 21 TC 25 Z9 27 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD MAY PY 1998 VL 120 IS 2 BP 357 EP 364 DI 10.1115/1.2824257 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA ZR720 UT WOS:000074007000010 ER PT J AU McCarthy, JF Shevenell, L AF McCarthy, JF Shevenell, L TI Processes controlling colloid composition in a fractured and karstic aquifer in eastern Tennessee, USA SO JOURNAL OF HYDROLOGY LA English DT Article DE colloids; karst; fractured; colloid stability; geochemical modeling ID OAK-RIDGE; TRANSPORT AB Groundwater was sampled from a number of wells along recharge pathways between fractured shale and karstic formations to evaluate the chemical and hydrologic mechanisms controlling the nature and abundance of groundwater colloids. The colloids recovered using low flow rate purging and sampling exhibited a composition and abundance consistent with lithology, flow paths, and effects of hydrology and aqueous chemistry on colloid mobilization and stability. In general, the larger-size colloids and Ca-containing colloids were more abundant in the karstic lithologies, while Na-containing colloids were more important in the shales. The composition of the colloids reflected recharge pathways from the fractured shale and dolomite formations on the ridges into the limestone in the valley floor. The Mg-colloids in the limestone reflect the possible contributions from the dolomite, while the Na, K, and Si reflect possible contributions from the shale, However, it was not possible to use the colloid composition as a signature to demonstrate colloid transport from one lithology to another. Mixing of recharge water from the shale with groundwater within the limestone formation and precipitation/dissolution reactions could account for the colloids present in the limestone without invoking transport of specific shale-derived colloids into the limestone formation. The abundance of colloids in groundwater appears to be controlled by both chemical factors affecting colloid stability, as well as physical factors related to hydrology (storm-driven recharge and water velocities). In general, colloids were more abundant in wells with low ionic strength, such as shallow wells in water table aquifers near sources of recharge at the top of the ridges, Increases in cation concentrations due to dissolution reactions along Bow paths were associated with decreases in colloid abundance. However, in spite of elevated ionic strength, colloid concentrations tended to be unexpectedly high in karstic wells that were completed in cavities or water-bearing fractures. The higher levels of colloids appear to be related to storm-driven changes in chemistry or flow rates that causes resuspension of colloids settled within cavities and fractures. Published by Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Nevada, Nevada Bur Mines & Geol, Reno, NV USA. RP McCarthy, JF (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008,Bethel Valley Rd, Oak Ridge, TN 37831 USA. EM mccarthyjf@ornl.gov NR 36 TC 24 Z9 24 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD MAY PY 1998 VL 206 IS 3-4 BP 191 EP 218 DI 10.1016/S0022-1694(98)00107-3 PG 28 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA ZV433 UT WOS:000074304100004 ER PT J AU Lipp, M Evans, WJ Garcia-Baonza, V Lorenzana, HE AF Lipp, M Evans, WJ Garcia-Baonza, V Lorenzana, HE TI Carbon monoxide: Spectroscopic characterization of the high-pressure polymerized phase SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT 2nd International Conference on Cryocrystals and Quantum Crystals (CC 97) CY SEP 07-12, 1997 CL POLANICA ZDROJ, POLAND SP Polish Acad Sci, W Trzebiatowski Inst Low Temperature & Struct Res, Wroclaw, Wroclaw TU, Inst Phys & Theoret Chem, Polish Phys Soc ID DIAMOND-ANVIL CELL; SOLID CO2; RAMAN; FILMS; NITROGEN; SPECTRA AB Solid carbon monoxide transforms to the delta-phase at about 48 kbar at room temperature. In this pressure regime (50 kbar and greater), carbon monoxide undergoes a transformation at room temperature to a light-pink solid, which has not been studied in detail and may be different from the delta-phase. Exposure to moderate light intensities at these P-T conditions converts the system to a dark red material. We report visible and infrared absorption as well as Raman investigations of this dark red substance, which likely contains a polymeric product of the photochemical reaction. This material is stable upon pressure release down to ambient conditions. Previous studies speculated that the dark red product was a mixture of poly-carbonsuboxide (C3O2) and oxalic anhydride (C2O3) In contrast, we present evidence that this material is composed of graphitic-like carbon, carbon dioxide, and possibly a polymerized net work containing -(C = O) - O - (C-) = C < as a repeating unit. C1 Univ Calif Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94551 USA. RP Lipp, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94551 USA. RI Garcia Baonza, Valentin/L-3826-2014 OI Garcia Baonza, Valentin/0000-0001-9994-0980 NR 24 TC 28 Z9 29 U1 0 U2 13 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAY PY 1998 VL 111 IS 3-4 BP 247 EP 256 DI 10.1023/A:1022267115640 PG 10 WC Physics, Applied; Physics, Condensed Matter SC Physics GA ZM106 UT WOS:000073505300004 ER PT J AU Bermejo, FJ de Bernabe, A Martinez, JL Senent, ML Cuello, GJ Cox, SFJ Dunstetter, F Trouw, F AF Bermejo, FJ de Bernabe, A Martinez, JL Senent, ML Cuello, GJ Cox, SFJ Dunstetter, F Trouw, F TI Magnetic dynamics in condensed oxygen: Recent experimental results SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT 2nd International Conference on Cryocrystals and Quantum Crystals (CC 97) CY SEP 07-12, 1997 CL POLANICA ZDROJ, POLAND SP Polish Acad Sci, W Trzebiatowski Inst Low Temperature & Struct Res, Wroclaw, Wroclaw TU, Inst Phys & Theoret Chem, Polish Phys Soc ID SOLID OXYGEN; ALPHA-OXYGEN; BETA-OXYGEN; RELAXATION; FIELDS AB The spin dynamics in the condensed phases of ambient-pressure molecular oxygen (liquid, plastic-crystalline (gamma-), magnetically disordered (beta-) and fully ordered alpha-O-2) is investigated by means of the concurrent use of neutron scattering and muon-spin relaxation. Above the alpha --> beta transition the magnetic dynamics is governed by fast paramagnetic fluctuations whose spectrum is determined from the S(Q, omega) dynamic structure factors accessible from inelastic neutron scattering. Such information is shown to provide a key to understand the non-trivial temperature dependence of longitudinal relaxation rates found in muon spin relaxation measurements. Recent neutron scattering measurements performed within the magnetically ordered alpha-phase under high-resolution conditions reveal the presence of a low-energy excitation of magnetic origin, unnoticed in a previous polarized-neutron experiment, which corresponds to the continuation to longer wavevectors of the spin-wave mode detected in antiferromagnetic resonance (AFMR) experiments carried out by optical means. C1 CSIC, E-28006 Madrid, Spain. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Ecole Polytech, Solides Irradies Lab, F-91128 Palaiseau, France. Argonne Natl Lab, Argonne, IL 60439 USA. RP Bermejo, FJ (reprint author), CSIC, Serrano 123, E-28006 Madrid, Spain. RI Cuello, Gabriel/C-5831-2009 OI Cuello, Gabriel/0000-0003-3844-0602 NR 46 TC 10 Z9 10 U1 0 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAY PY 1998 VL 111 IS 3-4 BP 287 EP 302 DI 10.1023/A:1022223300619 PG 16 WC Physics, Applied; Physics, Condensed Matter SC Physics GA ZM106 UT WOS:000073505300007 ER PT J AU Bishop, AR Gulacsi, M AF Bishop, AR Gulacsi, M TI Charge-magnon and -soliton states in the one-dimensional Hubbard model SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT ICM 97 Meeting CY 1997 CL CAIRNS, AUSTRALIA SP ICM DE Bethe ansatz; Hubbard model; magnons; one-dimensional systems; solitons ID COMPLEX WAVENUMBERS; EXCITATIONS; CHAIN AB We consider the charge excitations of the half-filled Hubbard chain which are related to electron pairs occupying the same lattice site. We have shown that the empty and doubly occupied site states corresponds to antikink and kink states in a continuum field theoretical approach, or to the magnon states of the ferromagnetic Heisenberg chain. i.e. they are charge-magnon states. Considering these particles fully interacting and by solving exactly the two-body scattering problem we obtained new bound excitation states of the charge-magnons. These are charge solitons, as they correspond to the solitons of the equivalent nonlinear Schroedinger equation. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Australian Natl Univ, Inst Adv Studies, Dept Theoret Phys, Canberra, ACT 0200, Australia. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Gulacsi, M (reprint author), Australian Natl Univ, Inst Adv Studies, Dept Theoret Phys, Canberra, ACT 0200, Australia. EM miklos.gulacsi@anu.edu.au NR 14 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAY PY 1998 VL 184 IS 3 BP 302 EP 306 DI 10.1016/S0304-8853(98)00027-4 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA ZH668 UT WOS:000073135200007 ER PT J AU Gordon, DA Lattier, DL Silbiger, RN Torsella, J Wolff, JO Smith, MK AF Gordon, DA Lattier, DL Silbiger, RN Torsella, J Wolff, JO Smith, MK TI Determination of genetic diversity and paternity in the gray-tailed vole (Microtus canicaudus) by RAPD-PCR SO JOURNAL OF MAMMALOGY LA English DT Article DE Microtus canicaudus; gray-tailed voles; DNA fingerprinting; genetic similarity; RAPD-PCR; pedigree analysis ID AMPLIFIED POLYMORPHIC DNA; POLYMERASE CHAIN-REACTION; POPULATION-GENETICS; MARKERS; CONSERVATION; VARIABILITY AB Genetic relatedness of gray-tailed voles (Microtus canicaudus) was determined by random amplified polymorphic DNA (RAPD). This work is the first reported use of the RAPD method for pedigree analysis of M. canicaudus and demonstrates the feasibility of RAPD for assessing paternity and genetic similarity between inbred and outbred individuals. Amplified polymorphisms and two statistical approaches were used to evaluate genetic similarities between individual Voles. DNA profiles of wild-caught (outbred) voles were significantly less similar than were inbred voles, using two different primers (P less than or equal to 0.03 and P less than or equal to 0.003). In pedigree analyses using three unrelated males in a discrimination test, indication of paternity was based upon bands shared by the progeny and the male in question. Non-sire males produced bands that were not seen in the probable father or offspring and, conversely, bands were found in the progeny that were apparently inherited only from the probable sire. The RAPD procedure may have wide applications in identifying genetic relationships among individuals to estimate genetic heterogeneity, determine parentage, and address questions concerning gene flow and kinship in feral vole populations. C1 US EPA, Natl Exposure Res Lab, Cincinnati, OH 45268 USA. Oak Ridge Inst Sci & Educ, Natl Exposure Res Lab, Cincinnati, OH 45268 USA. Pathol Associates Int Inc, Natl Exposure Res Lab, Cincinnati, OH 45268 USA. Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA. RP Gordon, DA (reprint author), US EPA, Natl Exposure Res Lab, 26 W Martin Luther King Dr, Cincinnati, OH 45268 USA. NR 49 TC 6 Z9 9 U1 0 U2 1 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 USA SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD MAY PY 1998 VL 79 IS 2 BP 604 EP 611 DI 10.2307/1382990 PG 8 WC Zoology SC Zoology GA ZP664 UT WOS:000073776100022 ER PT J AU Jorgensen, BR Shin, YC AF Jorgensen, BR Shin, YC TI Dynamics of spindle-bearing systems at high speeds including cutting load effects SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID DESIGN AB Increased use of high speed machining creates the need to predict spindle-bearing performance at high speeds. Previous spindle-bearing models simplify either spindle or bearing dynamics to the extent of prohibiting a detailed analysis of a spindle with high speed motion. At high speeds, centrifugal loading in the bearing causes stiffness softening, creating a change in natural frequency. Therefore, spindle modeling requires a comprehensive representation of the dynamics of shafts with complex geometry rotating at high speeds and supported by non-linear bearings. This paper presents a coupled system of spindle and bearing dynamic models with numerical solution. Spindle dynamics are modeled using the influence coefficient method of discrete lumped masses, based on Timoshenko beam theory. Both linens and rotational bearing stiffness are included in the spindle model through solution of the angular-contact bearing model. The parameters of cutting loads, tool mass, and rotational speed are analyzed, and all are shown to affect the natural frequency. The computer model is both rapid and robust, and shows excellent agreement with experimental analysis. C1 Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. RP Jorgensen, BR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Shin, Yung/E-4626-2011; OI Shin, Yung/0000-0003-3157-9345 NR 13 TC 40 Z9 50 U1 3 U2 17 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD MAY PY 1998 VL 120 IS 2 BP 387 EP 394 DI 10.1115/1.2830138 PG 8 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA ZR681 UT WOS:000074003100023 ER PT J AU Lee, SB Stock, SR Butts, MD Starr, TL Breunig, TM Kinney, JH AF Lee, SB Stock, SR Butts, MD Starr, TL Breunig, TM Kinney, JH TI Pore geometry in woven fiber structures: 0 degrees/90 degrees plain-weave cloth layup preform SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CHEMICAL-VAPOR INFILTRATION; REINFORCED SIC COMPOSITES; SILICON-CARBIDE AB Composite preform fiber architectures range from the very simple to the complex, and the extremes are typified by parallel continuous fibers and complicated three-dimensional woven structures. Subsequent processing of these preforms to produce dense composites may depend critically on the geometry of the interfiber porosity. The goal of this study is to fully characterize the structure of a 0 degrees/90 degrees cloth layup preform using x-ray tomographic microscopy (XTM). This characterization includes the measurement of intercloth channel widths and their variability, the transverse distribution of through-cloth holes, and the distribution of preform porosity. The structure of the intercloth porosity depends critically on the magnitude and direction of the offset between adjacent cloth layers. The structures observed include two-dimensional networks of open pipes linking adjacent holes, arrays of parallel one-dimensional pipes linking holes, and relatively closed channels exhibiting little structure, and these different structures would appear to offer very different resistances togas flow through the preform. These measurements, and future measurements for different fiber architectures, will yield improved understanding of the role of preform structure on processing. C1 Republ Korea Army Headquarters, Nonsan, Duma Namson, South Korea. Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. Chicago Bridge & Iron, Chicago, IL USA. Univ Calif San Francisco, Dept Restorat Dent, San Francisco, CA 94143 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Lee, SB (reprint author), Republ Korea Army Headquarters, Nonsan, Duma Namson, South Korea. NR 19 TC 32 Z9 33 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1998 VL 13 IS 5 BP 1209 EP 1217 DI 10.1557/JMR.1998.0172 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA ZJ975 UT WOS:000073272500023 ER PT J AU Paulik, SW Baskaran, S Armstrong, TR AF Paulik, SW Baskaran, S Armstrong, TR TI Mechanical properties of calcium- and strontium-substituted lanthanum chromite SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID FRACTURE-TOUGHNESS; INTERCONNECT; TEMPERATURE; CERAMICS; PHASE AB Mechanical properties of acceptor (calcium and strontium)-substituted lanthanum chromites are reported as a function of composition, temperature and environment. The strength dependence on temperature for these perovskite conductors was found to depend on the acceptor type, with the calcium-substituted chromites showing a significant reduction in strength with increasing temperature, while the strength of strontium-substituted chromites was essentially invariant with temperature. The decrease in strength observed upon annealing in highly reducing environments was correlated to changes in lattice structure, stoichiometry and fracture morphology. A significant observation was the decrease in the cohesive strength of the grains relative to grain boundaries, beyond a critical oxygen vacancy concentration in the chromites. The structural changes in the chromite lattice upon reduction also resulted in decreased fracture toughness. (C) 1998 Chapman & Hall. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Paulik, SW (reprint author), Pacific NW Lab, POB 999,Battelle Blvd, Richland, WA 99352 USA. NR 29 TC 45 Z9 46 U1 1 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAY 1 PY 1998 VL 33 IS 9 BP 2397 EP 2404 DI 10.1023/A:1004359925766 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 149DQ UT WOS:000077590200018 ER EF