FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Gray, LJ Paulino, GH AF Gray, LJ Paulino, GH TI Symmetric Galerkin boundary integral formulation for interface and multi-zone problems SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE boundary integral method; symmetric-Galerkin approximation; interfaces; multi-zone boundary element analysis; composite materials ID EFFICIENT ANALYTICAL INTEGRATION; FRACTURE-ANALYSIS; CURVED ELEMENTS; SCATTERING AB Domains containing an 'internal boundary', such as a bi-material interface, arise in many applications, e.g. composite materials and geophysical simulations. This paper presents a symmetric Galerkin boundary integral method for this important class of problems. In this situation, the physical quantities are known to satisfy continuity conditions across the interface, but no boundary conditions are specified. The algorithm described herein achieves a symmetric matrix of reduced size. Moreover, the symmetry can also be invoked to lessen the numerical work involved in constructing the system of equations, and thus the method is computationally very efficient. A prototype numerical example, with several variations in the boundary conditions and material properties, is employed to validate the formulation and corresponding numerical procedure. The boundary element results are compared with analytical solutions and with numerical results obtained with the finite element method. (C) 1997 by John Wiley & Sons, Ltd. C1 UNIV CALIF DAVIS,DEPT CIVIL & ENVIRONM ENGN,DAVIS,CA 95616. RP Gray, LJ (reprint author), OAK RIDGE NATL LAB,DIV MATH & COMP SCI,POB 2008,BLDG 6012,MS-6367,OAK RIDGE,TN 37831, USA. RI Paulino, Glaucio/A-2426-2008 NR 28 TC 75 Z9 75 U1 1 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD AUG 30 PY 1997 VL 40 IS 16 BP 3085 EP 3101 DI 10.1002/(SICI)1097-0207(19970830)40:16<3085::AID-NME194>3.0.CO;2-U PG 17 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA XP227 UT WOS:A1997XP22700009 ER PT J AU Kameda, J Bloomer, TE Sugita, Y Ito, A Sakurai, S AF Kameda, J Bloomer, TE Sugita, Y Ito, A Sakurai, S TI Mechanical properties of aluminized CoCrAlY coatings in advanced gas turbine blades SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 11th International Conference on the Strength of Materials (ICSMA-11) CY AUG 25-29, 1997 CL PRAGUE, CZECH REPUBLIC DE aluminized CoCrAlY coatings; layered microstructure; small punch testing method and ductility ID SMALL-PUNCH AB The microstructure/composition and mechanical properties (22-950 degrees C) in aluminized CoCrAIY coatings of advanced gas turbine blades have been examined using scanning Auger microprobe and a small punch (SP) testing method. Aluminized coatings were made of layered structure divided into four regions; (I) Al enriched and Cr depleted region, (II) Al and Cr graded region, (III) fine grained microstructure with a mixture of Al and Cr enriched phases and (IV) Ni/Co interdifusion zone adjacent to the interface. Coating regions I and II with high microhardness showed easier formation of brittle cracks in a wide temperature range, compared to regions III and IV. The coating region III had lower room temperature ductility and conversely higher elevated temperature ductility than the region IV due to a precipitous ductility increase above 730 degrees C. The integrity of aluminized coatings while in-service is discussed in light of the variation in the low cycle fatigue life as well as the ductility in the layered structure. (C) 1997 Elsevier Science S.A. C1 IOWA STATE UNIV SCI & TECHNOL,CATD,AMES,IA 50011. CHUBU ELECT POWER CO INC,ELECT POWER R&D CTR,NAGOYA,AICHI 458,JAPAN. HITACHI LTD,MECH ENGN RES LAB,HITACHI,IBARAKI 317,JAPAN. RP Kameda, J (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 11 TC 14 Z9 14 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE 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 AUG 30 PY 1997 VL 234 BP 489 EP 492 DI 10.1016/S0921-5093(97)00283-9 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA XV252 UT WOS:A1997XV25200118 ER PT J AU Schwarz, RB Wetteland, CJ Shen, TD Ustundag, E Sickafus, KE AF Schwarz, RB Wetteland, CJ Shen, TD Ustundag, E Sickafus, KE TI Vanadium-spinel composites for structural applications in hostile environments SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 11th International Conference on the Strength of Materials (ICSMA-11) CY AUG 25-29, 1997 CL PRAGUE, CZECH REPUBLIC DE composites; radiation resistance; toughness ID INDENTATION FRACTURE-TOUGHNESS; EQUATIONS; SOLIDS AB Vanadium-spinel composites are promising materials for structural applications in radiation environments. Powders of two vanadium-spinel composites, 20/80 vol.%, were prepared by (a) ball milling mixtures of vanadium and spinel powders (alloy VSLP) and (b) through a self-sustained reaction synthesis of vanadium, MgO, and Al powders (alloy VSHP). These powders were consolidated by hot isostatic pressing. Most of the V and spinel domains in the compacts are sub-micron in size. The compacts have K-c toughness values of 3.9, about three times the toughness obtained by hipping mixtures of commercial powders. (C) 1997 Elsevier Science S.A. C1 MST 4,LOS ALAMOS,NM 87545. RP Schwarz, RB (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,MAIL STOP K-765,LOS ALAMOS,NM 87545, USA. RI Ustundag, Ersan/C-1258-2009 OI Ustundag, Ersan/0000-0002-0812-7028 NR 12 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE 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 AUG 30 PY 1997 VL 234 BP 1091 EP 1094 DI 10.1016/S0921-5093(97)00388-2 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA XV252 UT WOS:A1997XV25200271 ER PT J AU Watson, EB Cherniak, DJ Hanchar, JM Harrison, TM Wark, DA AF Watson, EB Cherniak, DJ Hanchar, JM Harrison, TM Wark, DA TI The incorporation of Pb into zircon SO CHEMICAL GEOLOGY LA English DT Article DE zircon; lead; isotopes; crystal growth; crystal chemistry ID DIFFUSION; GEOCHEMISTRY; MONAZITE; APATITE; CRUSTAL; OLIVINE; FLUIDS; MODEL; DEPTH; ROCKS AB The incorporation of Pb into zircons grown from Pb-rich solutions was evaluated using three different approaches: (1) high-temperature growth of large crystals from Pb-silicate melts; (2) hydrothermal overplating of thin epitaxial layers on substrates of natural zircon; and (3) growth of small, homogeneously nucleated crystals from aqueous fluids. The melt-grown zircons (50-400 mu m) were crystallized from PbO-SiO2-ZrO2 (+/- P2O5) liquid at atmospheric pressure by cooling from 1430 degrees to 1350 degrees C. In the P2O5-free system, despite 66 wt% PbO in the melt, these zircons contain < 1 ppm Pb, yielding an apparent crystal/melt partition coefficient (D-Pb) for Pb2+ of 7 x 10(-7). Addition of similar to 5 wt% P2O5 to the melt results in uptake not only of P (similar to 3400 ppm) in the zircons but also Pb (similar to 1500 ppm), increasing the apparent D-Pb to about 10(-3). Hydrothermal overplating of ZrSiO4 was carried out at 1.5 GPa in a piston-cylinder apparatus by slow cooling from 500 degrees C or 550 degrees C to 140 degrees C of polished slabs of natural zircon immersed in zircon-saturated aqueous solutions containing either PbO2 or PbO + P2O5. In both cases, the resulting epitaxial layers of ZrSiO4 (similar to 60 nm thick) contain > 3 atom% Pb, with apparent zircon/fluid partition coefficients of 4.2 and 2.6, respectively, for Pb4+ and Pb2+. In contrast to the case of milt-grown zircons, available P is excluded from the aqueous epitaxial zircon, suggesting that charge balance is accomplished by H+ instead. Small (2-5 mu m) zircons grown by cooling aqueous solutions (PbO + SiO2 + ZrO2 +/- P2O5) from 800 degrees C or 900 degrees C contain similar to 0.25-0.5 atom% Pb (similar to 2-4 wt% PbO), yielding apparent D-Pb values of similar to 0.2-0.3. Available P5+ is incorporated in a 2:1 ratio with Pb2+, suggesting a specific charge-balance mechanism: [2P(5+) + Pb2+] = [2Si(4+) + Zr4+]. However, Pb enters the zircon even when P is unavailable, so H+ may again play a charge-balancing role. Because of the rapid, polythermal modes of zircon growth and the high Pb content of the experimental systems, the apparent partition coefficients should not be viewed as equilibrium values, but as qualitative indicators of Pb compatibility under various growth circumstances. The overall results are consistent with the low but variable levels of non-radiogenic (common) Pb in natural zircons. The increased compatibility of Pb in fluid-grown, low-temperature zircons suggests a possible fingerprint for zircons from hydrothermal and wet-metamorphic rocks, i.e., high concentrations of common Pb. (C) 1997 Elsevier Science B.V. C1 ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. UNIV CALIF LOS ANGELES,DEPT EARTH & SPACE SCI,LOS ANGELES,CA 90024. RP Watson, EB (reprint author), RENSSELAER POLYTECH INST,EARTH & ENVIRONM SCI DEPT,TROY,NY 12180, USA. RI Harrison, Timothy/E-7443-2012; UCLA, SIMS/A-1459-2011 NR 40 TC 93 Z9 113 U1 5 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD AUG 29 PY 1997 VL 141 IS 1-2 BP 19 EP 31 DI 10.1016/S0009-2541(97)00054-5 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XZ812 UT WOS:A1997XZ81200002 ER PT J AU Althorpe, SC Kouri, DJ Hoffman, DK AF Althorpe, SC Kouri, DJ Hoffman, DK TI State-to-state reaction probabilities from the time-independent wavepacket reactant-product decoupling equations: Application to the three-dimensional H+H-2 reaction (for J=0) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID LIPPMANN-SCHWINGER EQUATIONS; POTENTIAL-ENERGY SURFACE; 6 DIMENSIONS; SCATTERING; SCHRODINGER; H-3 AB The reactant-product decoupling (RPD) equations are a rigorous formulation of quantum reactive scattering recently introduced by Peng and Zhang. Solving the RPD equations yields state-to-state reaction probabilities from a set of decoupled wavepacket propagations, each of which is confined to an arrangement of the reaction. Previously, we derived the time-independent wavepacket version of the RPD equations, and developed an efficient Chebyshev-based propagator for solving them. In this Letter we apply our method to 3D reactive scattering, presenting state-to-state reaction probabilities for the H + H-2 reaction (for J = 0). (C) 1997 Elsevier Science B.V. C1 UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP Althorpe, SC (reprint author), UNIV HOUSTON,DEPT CHEM,UNIV PK,HOUSTON,TX 77204, USA. NR 26 TC 13 Z9 13 U1 0 U2 4 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 AUG 29 PY 1997 VL 275 IS 3-4 BP 173 EP 180 DI 10.1016/S0009-2614(97)00744-6 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV887 UT WOS:A1997XV88700007 ER PT J AU Gatley, SJ Lan, RX Pyatt, B Gifford, AN Volkow, ND Makriyannis, A AF Gatley, SJ Lan, RX Pyatt, B Gifford, AN Volkow, ND Makriyannis, A TI Binding of the non-classical cannabinoid CP 55,940, and the diarylpyrazole AM251 to rodent brain cannabinoid receptors SO LIFE SCIENCES LA English DT Article DE CP 55,940; AM251; cannabinoid receptor binding; brain ID RAT-BRAIN; CB1 RECEPTOR; LOCALIZATION; ANTAGONIST; AGONISTS; POTENT; MICE AB The binding of [[I-123]AM251 (a radioiodinated analog of the cannabinoid CB1 receptor antagonist SR141716A) was compared to that of [H-3]CP 55,940 in mouse and rat brain preparations. Scatchard analysis of the binding of [I-123]AM251 and [H-3]CP 55,940 to membranes prepared from mouse cerebellum, striatum and hippocampus yielded similar Bmax values (15-41 pmol/g wet wt tissue). Kd values were lower for [I-123]AM251 (0.23-0.62 nM) than for [H-3]CP 55,940 (1.3-4 nM). CP 55:940 and SR141716A increased dissociation of [I-123]AM251 from binding sites in mouse cerebellar homogenates to a similar extent. The structurally dissimilar cannabinoid receptor ligands THC, methanandamide, WIN 55 212-2, CP 55,940 and SR141716A were each able to fully compete with binding of both [I-123]AM251 and [H-3]CP 55,940 in mouse cerebellum. In vitro autoradiography demonstrated that the distribution of binding sites for [I-123]AM251 in rat brain was very similar to published distributions of binding sites for [3H]CP 55,940. Together, these observations suggest that AM251 binds to the same site (the cannabinoid CB1 receptor) in rodent brains as CP 55,940. However, the binding site domains which interact with AM251 and CP 55,940 may not be identical, since IC50 values for cannabinoid receptor ligands depended on whether [I-123]AM251 or [H-3]CP 55,940 was used as radioligand. (C) 1997 Elsevier Science Inc. C1 UNIV CONNECTICUT,SCH PHARM,STORRS,CT 06269. UNIV CONNECTICUT,DEPT MOL & CELL BIOL,STORRS,CT 06269. RP Gatley, SJ (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 16 TC 47 Z9 47 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0024-3205 J9 LIFE SCI JI Life Sci. PD AUG 29 PY 1997 VL 61 IS 14 BP PL191 EP PL197 PG 7 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA XV269 UT WOS:A1997XV26900013 ER PT J AU Nicolussi, GK Davis, AM Pellin, MJ Lewis, RS Clayton, RN Amari, S AF Nicolussi, GK Davis, AM Pellin, MJ Lewis, RS Clayton, RN Amari, S TI s-process zirconium in presolar silicon carbide grains SO SCIENCE LA English DT Article ID IONIZATION MASS-SPECTROMETRY; INTERSTELLAR GRAINS; MURCHISON METEORITE; CARBONACEOUS METEORITES; ISOTOPIC COMPOSITIONS; NOBLE-GASES; PROCESS BA; GRAPHITE; ANOMALIES; ABUNDANCES AB The isotopic composition of zirconium in silicon carbide grains from the Murchison meteorite was measured by resonant ionization mass spectrometry of laser-ablated neutral atoms. These grains are condensates from the atmospheres of red giant stars that existed before the formation of our sun and solar system, and they contain records of nucleosynthesis in these stars. The r-process-dominated isotope zirconium-96 was depleted by more than a factor of 2 compared with the s-process-dominated isotopes zirconium-90, zirconium-91, zirconium-92, and zirconium-94, in agreement with expectations for neutron capture nucleosynthesis in asymptotic giant branch stars. C1 ARGONNE NATL LAB,DIV CHEM & MAT SCI,ARGONNE,IL 60439. UNIV CHICAGO,ENRICO FERMI INST,DEPT GEOPHYS SCI,CHICAGO,IL 60637. RP Nicolussi, GK (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT CHEM,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. RI Pellin, Michael/B-5897-2008; OI Pellin, Michael/0000-0002-8149-9768; Davis, Andrew/0000-0001-7955-6236 NR 41 TC 111 Z9 111 U1 1 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD AUG 29 PY 1997 VL 277 IS 5330 BP 1281 EP 1283 DI 10.1126/science.277.5330.1281 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XT827 UT WOS:A1997XT82700047 ER PT J AU Davis, WB Wasielewski, MR Ratner, MA Mujica, V Nitzan, A AF Davis, WB Wasielewski, MR Ratner, MA Mujica, V Nitzan, A TI Electron transfer rates in bridged molecular systems: A phenomenological approach to relaxation SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DISTANCE DEPENDENCE; SUPRAMOLECULAR SYSTEMS; DYNAMICAL SEMIGROUPS; ORGANIC-MOLECULES; REDFIELD EQUATION; QUANTUM DYNAMICS; PROTEINS; MATRIX; PATHWAYS; CHARGE AB A model for bridge-assisted, long-range electron transfer in a molecule interacting with a dissipative external bath is presented. The effects of the system-bath interaction are included phenomenologically in the evolution of the system density matrix as energy dephasings on the bridge sites. When the bridge dephasings are small, the steady state ET rate in this model is found to be the sum of two competing terms; the first is a McConnell-type rate arising from direct tunneling from donor to acceptor, and the second is a dephasing dependent, length-independent scattering channel through the bridge sites. In the limit of large dephasings, an incoherent channel dominates the dynamics and leads to ET rates that can become only weakly dependent (k(ET) proportional to 1/N) on the number of bridge sites in the system, for multisite bridges. C1 ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. CENT UNIV VENEZUELA, FAC CIENCIAS, ESCUELA QUIM, CARACAS 1020A, VENEZUELA. TEL AVIV UNIV, SCH CHEM, IL-69978 TEL AVIV, ISRAEL. RP NORTHWESTERN UNIV, DEPT CHEM, 2145 SHERIDAN RD, EVANSTON, IL 60208 USA. RI Abraham, Nitzan/A-9963-2008 NR 81 TC 156 Z9 157 U1 0 U2 17 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 AUG 28 PY 1997 VL 101 IS 35 BP 6158 EP 6164 DI 10.1021/jp970909c PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XT955 UT WOS:A1997XT95500005 ER PT J AU Mezyk, SP Bartels, DM AF Mezyk, SP Bartels, DM TI Temperature dependence of hydrogen atom reaction with nitrate and nitrite species in aqueous solution SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PULSE-RADIOLYSIS; EPR MEASUREMENT; ARRHENIUS PARAMETERS; HYDRATED ELECTRONS; WATER RADIOLYSIS; RATE-CONSTANT; DECAY; ACID; NO2 AB Arrhenius parameters for the reaction of hydrogen atoms with NO3-, HNO2, and NO2- in aqueous solution have been determined by the use of pulse radiolysis and electron paramagnetic resonance free induction decay attenuation measurements. At 25.0 degrees C, the calculated rate constants for these compounds are (5.61 +/- 0.51) x 10(6), (3.86 +/- 0.09) x 10(8), and (1.62 +/- 0.05) x 10(9) dm(3) mol(-1) s(-1) respectively, with corresponding activation energies of 48.7 +/- 1.0 (15.2-84.5 degrees C), 21.54 +/- 0.69 (5.9-62.8 degrees C) and 15.59 +/- 0.36 (6.2-86.8 degrees C) kJ mol(-1). Computer modeling of these systems suggests that . H atom reaction with either anion directly produces hydroxide anion and the corresponding NOx radical. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP Mezyk, SP (reprint author), ATOM ENERGY CANADA LTD,WHITESHELL LABS,RES CHEM BRANCH,PINAWA,MB R0E 1L0,CANADA. NR 54 TC 30 Z9 30 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 28 PY 1997 VL 101 IS 35 BP 6233 EP 6237 DI 10.1021/jp970934i PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XT955 UT WOS:A1997XT95500013 ER PT J AU Wolf, M Yang, DL Durant, JL AF Wolf, M Yang, DL Durant, JL TI A comprehensive study of the reaction NH2+NO->products: Reaction rate coefficients, product branching fractions, and ab Initio calculations SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID NH2 + NO; RATE-CONSTANT; THEORETICAL CHARACTERIZATION; VIBRATIONAL FREQUENCIES; KINETIC MEASUREMENTS; GAUSSIAN-2 THEORY; THERMAL DENOX; FLOW REACTOR; RADICALS; AMMONIA AB We have undertaken a comprehensive study of the reaction NH2((XB1)-B-2) + NO --> N-2 + H2O (1a) and NH2(X B-2(1)) + NO --> N2H + OH --> N-2 + H + OH (1b). Experimental measurements of the reaction rate coefficient and product branching fraction are combined with accurate ab initio calculations to give a detailed picture of this important reaction. The rate constant of reaction 1 was investigated in the temperature range 203 K less than or equal to T less than or equal to 813 K using the laser photolysis/CW laser-induced fluorescence technique for production and detection of NH2. The rate coefficient was found to be pressure independent between 10 and 100 Torr and is well described by k(1)(T) = 1.65 x 10(-7)T(-154)exp (-93 K/T) cm(3)/(molecule.s). The deuterium kinetic isotope effect for the reactions of NH2 and ND2 with NO was investigated at temperatures between 210 and 481 K. A small, temperature-independent isotope effect of k(H)/k(D) 1.05 +/- 0.03 was found. Additional experimental work focused on measuring the product branching fraction for production of OH, Phi(lb), and its deuterium isotope effect at room temperature. Measurements were performed using the discharge flow technique with mass spectrometric detection of products. OH from channel Ib was reacted with excess CO and measured as CO2. The room temperature branching fraction was measured as Phi(lb) = 9.0 +/- 2.5% (NH2 +/- NO; T = 298 K) and Phi(lb) = 5.5 +/- 0.7% (ND2 + NO; T = 298 K). Theoretical calculations have characterized the stationary points on the potential energy surface connecting reactants with products using G2 and G2Q levels of theory. These calculations support the experimentally observed temperature dependences and kinetic isotope effects. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. NR 63 TC 21 Z9 21 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 28 PY 1997 VL 101 IS 35 BP 6243 EP 6251 DI 10.1021/jp9713165 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XT955 UT WOS:A1997XT95500015 ER PT J AU Peterson, KA Dunning, TH AF Peterson, KA Dunning, TH TI Benchmark calculations with correlated molecular wave functions .11. Energetics of the elementary reactions F+H-2, O+H-2, and H'+HCl SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; GAUSSIAN-BASIS SETS; POTENTIAL-ENERGY SURFACE; CLASSICAL BARRIER HEIGHT; COUPLED-CLUSTER METHOD; CONSISTENT BASIS-SETS; ANO BASIS-SETS; F + H-2; ACTIVATION-ENERGIES; TRIPLE EXCITATIONS AB An explicit treatment of electron correlation is required to predict accurate energetics, barrier heights, and saddle point geometries for chemical reactions. Several theoretical methods for treating electron correlation (multireference configuration interaction, perturbation theory, and coupled cluster methods) have been thoroughly evaluated for the F(P-2) + H-2(X-1 Sigma(g)(+)) and O(P-3) + H-2(X-1 Sigma(g)(+)) abstraction reactions as well as for the H'(2S) + HCl(X-1 Sigma(+)) exchange reaction using correlation consistent basis sets. The basis set dependence of the reaction energy defects, barrier heights, and saddle point geometries have been determined for each theoretical method. Addition of diffuse functions to the basis set (aug-cc-pVnZ) was found to substantially increase the convergence rate. Calculations with the largest basis set (aug-cc-pV5Z) allowed an unambiguous comparison of the relative performance of each correlation method. For each reaction, the R-UCCSD(T) results closely parallel the most accurate MRCI results and are in good agreement with experiment. In contrast, unrestricted perturbation theory methods predict barriers that are too large by 2.7-4.4 kcal/mol (MP2), 3.5-4.2 kcal/mol (MP3), and 1.3-1.7 kcal/mol (MP4). C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. RP Peterson, KA (reprint author), WASHINGTON STATE UNIV, DEPT CHEM, RICHLAND, WA 99352 USA. NR 67 TC 49 Z9 49 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 28 PY 1997 VL 101 IS 35 BP 6280 EP 6292 DI 10.1021/jp970676p PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XT955 UT WOS:A1997XT95500019 ER PT J AU Adam, J Stadler, A Pena, MT Gross, F AF Adam, J Stadler, A Pena, MT Gross, F TI Effects of relativistic dynamics in pp->pp pi(0) near threshold SO PHYSICS LETTERS B LA English DT Article ID TOTAL CROSS-SECTION; NEAR-THRESHOLD; EXCHANGE; P+P->P+P+PI-0; PI AB The cross-section for threshold pi(0) production in proton-proton collisions is evaluated in the framework of the covariant spectator description, The negative energy intermediate states are included non-perturbatively and seen to yield a considerably smaller contribution, when compared to perturbative treatments. A family of OBE-models with different off-shell scalar coupling is considered. (C) 1997 Elsevier Science B.V. C1 ACAD SCI CZECH REPUBL,INST NUCL PHYS,CZ-25068 PRAGUE,CZECH REPUBLIC. UNIV LISBON,CTR FIS NUCL,P-1699 LISBON,PORTUGAL. INST SUPER TECN,DEPT FIS,P-1096 LISBON,PORTUGAL. COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23185. RP Adam, J (reprint author), JEFFERSON LAB,12000 JEFFERSON AVE,NEWPORT NEWS,VA 23606, USA. RI Stadler, Alfred/C-5550-2009; Adam, Jiri/G-9785-2014; Pena, Teresa/M-4683-2013 OI Stadler, Alfred/0000-0002-9596-0770; Pena, Teresa/0000-0002-3529-2408 NR 19 TC 19 Z9 19 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 AUG 28 PY 1997 VL 407 IS 2 BP 97 EP 102 DI 10.1016/S0370-2693(97)00732-6 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP971 UT WOS:A1997XP97100001 ER PT J AU Satula, W Dean, DJ Gary, J Mizutori, S Nazarewicz, W AF Satula, W Dean, DJ Gary, J Mizutori, S Nazarewicz, W TI On the origin of the Wigner energy SO PHYSICS LETTERS B LA English DT Article ID NUCLEAR AB Surfaces of experimental masses of even-even and odd-odd nuclei exhibit a sharp slope discontinuity at N = Z. This cusp (Wigner energy), reflecting an additional binding in nuclei with neutrons and protons occupying the same shell model orbitals, is usually attributed to neutron-proton pairing correlations. A method is developed to extract the Wigner term from experimental data. Both empirical arguments and shell-model calculations suggest that the Wigner term can be traced back to the isospin T = 0 part of nuclear interaction. The structure of the Wigner energy is analyzed in terms of neutron-proton pairs of a given angular momentum and isospin. In particular, we find that the Wigner term cannot be solely explained in terms of correlations between the neutron-proton J = 1, T = 0 (deuteron-like) pairs. (C) 1997 Elsevier Science B.V. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. UNIV WARSAW,INST THEORET PHYS,PL-00681 WARSAW,POLAND. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP Satula, W (reprint author), OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,POB 2008,OAK RIDGE,TN 37831, USA. OI Dean, David/0000-0002-5688-703X NR 34 TC 124 Z9 126 U1 1 U2 5 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 AUG 28 PY 1997 VL 407 IS 2 BP 103 EP 109 DI 10.1016/S0370-2693(97)00711-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP971 UT WOS:A1997XP97100002 ER PT J AU Brambilla, N Vairo, A AF Brambilla, N Vairo, A TI Non-perturbative dynamics of the heavy-light quark system in the non-recoil limit SO PHYSICS LETTERS B LA English DT Article ID RELATIVISTIC WAVE-EQUATIONS; RIGOROUS QCD EVALUATION; WILSON LOOP; QUANTUM CHROMODYNAMICS; Q(Q)OVER-BAR SYSTEMS; VACUUM; CONFINEMENT; ANTIQUARK; DERIVATION; CONDENSATE AB Starting from the relativistic gauge-invariant quark-antiquark Green function we obtain the relevant interaction in the one-body limit, which can be interpreted as the kernel of a non-perturbative Dirac equation, We study this kernel in different kinematic regions, reproducing, in particular, for heavy quark the potential case and sum rules results. We discuss the relevance of the result for heavy-light mesons and the relation with the phenomenological Dirac equations used up to now in the literature. (C) 1997 Elsevier Science B.V. C1 JEFFERSON LAB,NEWPORT NEWS,VA 23606. HAMPTON UNIV,NUCL HIGH ENERGY PHYS,HAMPTON,VA 23668. IST NAZL FIS NUCL,SEZ MILANO,I-20133 MILAN,ITALY. RP Brambilla, N (reprint author), UNIV HEIDELBERG,INST THEORET PHYS,PHILOSOPHENWEG 19,D-69120 HEIDELBERG,GERMANY. RI Brambilla, Nora/O-9943-2015 NR 44 TC 39 Z9 41 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 AUG 28 PY 1997 VL 407 IS 2 BP 167 EP 173 DI 10.1016/S0370-2693(97)00749-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP971 UT WOS:A1997XP97100013 ER PT J AU vonRottkay, K Rubin, M Wen, SJ AF vonRottkay, K Rubin, M Wen, SJ TI Optical indices of electrochromic tungsten oxide SO THIN SOLID FILMS LA English DT Article DE electrochromic; tungsten oxide; complex refractive index; colored state ID SPECTROSCOPIC ELLIPSOMETRY; FILMS; CONSTANTS AB Tungsten trioxide (WO3) is the most widely used material for the active layer of electrochromic devices. Knowledge of the complex refractive index over the range of coloration states is required for device design. Optical constants of WO3 over the whole solar spectrum were determined as a function of injected charge. Films of WO3 were prepared by electron-beam evaporation, then colored in several steps by reduction with lithium (Li) up to 68 mC cm(-2) mu m(-1) injected charge. Measurements included variable-angle spectroscopic ellipsometry and spectroscopic transmittance and reflectance at normal incidence. Analysis was complicated by the fact that a transparent-conducting layer of indium tin oxide (ITO) was required to perform lithiation. Optical indices of the glass substrate and ITO transparent conductor were determined separately and then fixed in the model. The indices of WO3 could then be extracted from measurements on the complete structure. A parametric dispersion model corresponding to Gaussian broadening of the oscillators was used to represent the dielectric response of WO3. (C) 1997 Elsevier Science S.A. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 19 TC 46 Z9 46 U1 2 U2 15 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD AUG 28 PY 1997 VL 306 IS 1 BP 10 EP 16 DI 10.1016/S0040-6090(97)00254-X PG 7 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA YB667 UT WOS:A1997YB66700003 ER PT J AU Fan, B Fontenot, DL Larsen, RW Simpson, MC Shelnutt, JA Falcon, R Martinez, L Niu, S Zhang, S Niemczyk, T Ondrias, MR AF Fan, B Fontenot, DL Larsen, RW Simpson, MC Shelnutt, JA Falcon, R Martinez, L Niu, S Zhang, S Niemczyk, T Ondrias, MR TI Synthesis and physical characterization of novel heme-based model systems for photoinitiated electron transfer .1. Complexation of a RuProHis bifunctional peptide and microperoxidase-11 SO INORGANIC CHEMISTRY LA English DT Article ID CYTOCHROME-C; PHOTOCHEMISTRY; DEPENDENCE; TRIS(2,2'-BIPYRIDINE)RUTHENIUM(II); PHOTOPHYSICS; PORPHYRINS; TRANSIENT; OXIDASE; ENERGY AB This paper describes the synthesis and initial physical characterization of a new type of model system for the investigation of photoinitiated electron transfer (ET) in proteins and polypeptides. This system is based upon a derivative of a heme-containing digestion product of cytochrome c, microperoxidase-11 (MP-11). The vacant axial position of the five-coordinate heme of MP-11 is coordinated to the terminal histidine of a dipeptide having a photoactive ruthenium tris(bipyridine) moiety at its other end (RuProHis). Photoexcitation of the ruthenium group results in rapid (k(ET) > 10(7) s(-1)), reversible ET to the ferric heme. The equilibrium properties of MP-11 and the MP-11/Ru(peptide) complex were characterized with optical absorption, luminescence, and resonance Raman (RR) spectroscopies. Molecular modeling was also employed to examine the structure and energetics of the equilibrium species. Clear evidence for reversible photoinduced ET was observed in time-resolved luminescence and transient resonance Raman studies of the MP-11/RuProHis samples. C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. UNIV HAWAII,DEPT CHEM,HONOLULU,HI 96822. SANDIA NATL LABS,FUEL SCI DIV,ALBUQUERQUE,NM 87185. RI Shelnutt, John/A-9987-2009; Simpson, Miriam/C-4237-2011 OI Shelnutt, John/0000-0001-7368-582X; NR 34 TC 6 Z9 6 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD AUG 27 PY 1997 VL 36 IS 18 BP 3839 EP 3846 DI 10.1021/ic9700415 PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA XT977 UT WOS:A1997XT97700010 ER PT J AU Fan, B Simpson, MC Shelnutt, JA Martinez, L Falcon, R Buranda, T Pastuszyn, AJ Ondrias, MR AF Fan, B Simpson, MC Shelnutt, JA Martinez, L Falcon, R Buranda, T Pastuszyn, AJ Ondrias, MR TI Synthesis and physical characterization of novel heme-based model systems for photoinitiated electron transfer .2. Direct ruthenation of microperoxidase-11 SO INORGANIC CHEMISTRY LA English DT Article ID CYTOCHROME-C; DERIVATIVES; TRANSIENT; OXIDASE AB This paper describes the design, synthesis, and initial characterization of a second type of model electron transfer system based upon microperoxidase-11 (MP-11) that differs significantly from those described in the preceding article. In this system, a photoactive ruthenium tris(bipyridyl) donor is covalently attached directly to MP-11. Peptide digestion followed by chromatographic analysis was used to establish that the ruthenium moiety bonds to the lysine residue of the MP-11 peptide. This arrangement eliminates complications arising from the equilibrium complexation of ruthenium donor and heme acceptor required for the model systems described in the previous article and leaves an axial position in the octahedral geometry of the heme iron open for ligation. Various optical spectroscopies and molecular modeling calculations were employed to characterize the equilibrium properties and interchromophore interactions of RuMP-11. Preliminary luminescence-quenching, transient absorption, and transient resonance Raman studies demonstrated that rapid reversible electron transfer can be photoinitiated in this system. C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,DEPT BIOCHEM,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,FUEL SCI DIV,ALBUQUERQUE,NM 87185. RI Shelnutt, John/A-9987-2009; Simpson, Miriam/C-4237-2011 OI Shelnutt, John/0000-0001-7368-582X; NR 26 TC 2 Z9 2 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD AUG 27 PY 1997 VL 36 IS 18 BP 3847 EP 3853 DI 10.1021/ic970040c PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA XT977 UT WOS:A1997XT97700011 ER PT J AU Xie, XB McCarley, RE AF Xie, XB McCarley, RE TI Synthesis, characterization, and structure of mixed chloride-selenide tungsten cluster complexes SO INORGANIC CHEMISTRY LA English DT Article ID CHEVREL PHASES; COORDINATION CHEMISTRY; OCTAHEDRAL CLUSTERS; MOLYBDENUM; SALTS; UNIT AB The first examples of mixed halide-chalcogenide hexatungsten clusters as the molecular complexes, [W6Se8-xClx(PEt3)(6)](+), were prepared via the reaction of W6Cl12 With Na2Se and PEt3 in refluxing toluene. Single crystals of the mixed chloride-selenide cluster cationic complexes were grown from chloroform solution. The structures of two crystals from different preparations, using Na2Se and K2Se as reagents, were determined and found to have different compositions, [W6Se7.0Cl1.0(PEt3)(6)][Cl(CHCl3)(6)] and [W6Se6.4Cl1.6(PEt3)(6)][Cl(CHCl3)(6)], respectively. In the latter case the crystal contains both the 20-electron cluster [W6Se7Cl(PEt3)(6)](+) and the 21-electron cluster [W6Se6Cl2(PEt3)(6)](+) in the mole fractions 0.40 and 0.60, respectively. The two crystals were isomorphous: hexagonal, , Z = 3, a = 18.921(4) Angstrom, c = 21.275(4) Angstrom and a = 18.908(5) Angstrom, c = 21.306(5) Angstrom, respectively. The bridging chlorine and selenium atoms are disordered over all the bridging ligand sites in both structures. In the unique [Cl(CHCl3)(6)](-) anion unit, six chloroform solvent molecules are octahedrally coordinated to a chloride anion via hydrogen bonding. C1 IOWA STATE UNIV SCI & TECHNOL,USDOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 31 TC 12 Z9 12 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD AUG 27 PY 1997 VL 36 IS 18 BP 4011 EP 4016 DI 10.1021/ic970038l PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA XT977 UT WOS:A1997XT97700030 ER PT J AU Park, YW Luo, JK Schultz, PG Kirsch, JF AF Park, YW Luo, JK Schultz, PG Kirsch, JF TI Noncoded amino acid replacement probes of the aspartate aminotransferase mechanism SO BIOCHEMISTRY LA English DT Article ID SITE-DIRECTED MUTAGENESIS; ESCHERICHIA-COLI; SUBSTRATE-SPECIFICITY; TYROSINE AMINOTRANSFERASE; PROTEINS; ENZYME; CATALYSIS; MUTATION; MUTANT; BOND AB The primary role of Tyr225 in the aspartate aminotransferase mechanism is to provide a hydrogen bond to stabilize the 3'O- functionality of bound pyridoxal phosphate. The strength of this hydrogen bond is perturbed by replacement of Tyr225 with 3-fluoro-L-tyrosine (FlTyr) by in vitro transcription/translation. This mutant enzyme exhibits k(cat)/K-M(Asp) values that are near to those of wild type enzyme; however, the k(cat)/K-M(Asp) vs pH profile is much sharper with similar pK(a)s of similar to 7.5 for both the ascending and descending limbs. The pK(a)s are assigned to the endocyclic proton of the internal aldimine and to the bridging hydrogen bond, respectively. The pK(a)s in the k(cat) vs pH profile of 7.2 and 8.7 are assigned to the epsilon-NH3+ Of lysine 258 and to the endocyclic protons of the ketimine complex, respectively. Arginine 292, forms a salt bridge with the B-COOH of the substrate, aspartate. An improvement on the earlier attempt to invert the substrate charge specificity via R292D mutation-induced arginine transaminase activity [Cronin, C. N., & Kirsch, J. F. (1988) Biochemistry 27, 4572-4579] is described. Here Arg292 is replaced with homoglutamate (R292hoGlu). This construct exhibits 6.8 x 10(4)-fold greater activity for the cationic substrate D,L-[C-alpha-H-3]-alpha-amino-beta-guanidinopropionic acid (D,L-[C-alpha-H-3]AGPA) than does wild type enzyme. The gain in selectivity for this substrate is at least 4500-fold greater than that achieved in the 1988 experiment, i.e., {(k(cat)/K-m)(R292hoGlu)/(k(cat)/K-M)(WT) (D,L-[C-alpha-H-3]AGPA)} greater than or equal to 4500 x {(k(cat)/K-M)(R292D)/(k(cat)/K-M)(WT) (L-arginine)}. The value of (k(cat)/K-M)(R292D) is 0.43 M-1 s(-1) with L-Arg while (k(cat)/K-M)(R292hoGlu) is 29 M-1 s(-1) with D,L-[C-alpha-H-3]AGPA (it is assumed that the D-enantiomer is unreactive). The latter value is the lower limit because of the uncertain value of H-3 kinetic isotope effect. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,HOWARD HUGHES MED INST,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MOL & CELL BIOL,DIV BIOCHEM & MOL BIOL,BERKELEY,CA 94720. FU NIGMS NIH HHS [GM 35393] NR 36 TC 13 Z9 13 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 26 PY 1997 VL 36 IS 34 BP 10517 EP 10525 DI 10.1021/bi970298e PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XT761 UT WOS:A1997XT76100018 PM 9265632 ER PT J AU Friedman, DJ Kibbler, AE Reedy, R AF Friedman, DJ Kibbler, AE Reedy, R TI Selection of substrate orientation and phosphorus flux to achieve p-type carbon doping of Ga0.5In0.5P by molecular beam epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID GAAS; GROWTH AB We show that the p-type doping of Ga0.5In0.5P grown by solid-source molecular beam epitaxy using CBr4 as a carbon source is very strongly dependent upon the phosphorus flux and upon the substrate misorientation from (100). High densities of A-type steps and low phosphorus flux favor the incorporated carbon acting as a p-type dopant. We demonstrate that with the substrate orientation and phosphorus flux chosen to satisfy these two criteria, doping of C:Ga0.5In0.5P into the mid-10(18) holes/cm(3) range can be achieved for the as-grown material. (C) 1997 American Institute of Physics. RP Friedman, DJ (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. RI Schaff, William/B-5839-2009 NR 16 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 25 PY 1997 VL 71 IS 8 BP 1095 EP 1097 DI 10.1063/1.119737 PG 3 WC Physics, Applied SC Physics GA XR754 UT WOS:A1997XR75400035 ER PT J AU Hirsch, MT Wolk, JA Walukiewicz, W Haller, EE AF Hirsch, MT Wolk, JA Walukiewicz, W Haller, EE TI Persistent photoconductivity in n-type GaN SO APPLIED PHYSICS LETTERS LA English DT Article ID DX CENTERS; SEMICONDUCTORS; RELAXATION; KINETICS AB We report on the spectral and temperature dependence of persistent photoconductivity (PPC) in metal-organic chemical vapor deposition grown unintentionally doped n-type GaN. The PPC effect is detectable up to temperatures of at least 352 K, the highest temperature used in this study. At 77 K, the conduction persists at a level 80% higher than the equilibrium dark conduction for over 10(4) s after removing the excitation. We have determined the spectral dependence for the optical cross section for PPC and obtain an optical ionization energy of similar to 2.7 eV. The temperature dependence of the photoconductivity decay and its nonexponential shape are explained by a distribution of capture barriers with a mean capture barrier of 0.2 eV and a width of similar to 26 meV. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 16 TC 116 Z9 119 U1 5 U2 32 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 25 PY 1997 VL 71 IS 8 BP 1098 EP 1100 DI 10.1063/1.119738 PG 3 WC Physics, Applied SC Physics GA XR754 UT WOS:A1997XR75400036 ER PT J AU Kwok, SH Yu, PY Uchida, K Arai, T AF Kwok, SH Yu, PY Uchida, K Arai, T TI Band alignments in GaInP/GaP/GaAs/GaP/GaInP quantum wells SO APPLIED PHYSICS LETTERS LA English DT Article ID VAPOR-PHASE EPITAXY; PRESSURE; GAINP; HETEROSTRUCTURES; OFFSETS AB Pressure-dependent photoluminescence (PL) in several GaInP(ordered)-GaAs quantum well structures grown by metal organic vapor phase epitaxy is reported. Quantum well emission from GaAs is observed only in structures when thin (similar to 2 nm) GaP layers an inserted between the GaAs well and the GaInP barrier. By extrapolating the energies of the various inter and intralayer PL transitions observed under pressures (up to 5.5 GPa) to zero pressure, the different band offsets of the heterostructure have been determined. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NIPPON SANSO CO,TSUKUBA LABS,TSUKUBA,IBARAKI 30033,JAPAN. RP Kwok, SH (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 17 TC 15 Z9 15 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 25 PY 1997 VL 71 IS 8 BP 1110 EP 1112 DI 10.1063/1.119742 PG 3 WC Physics, Applied SC Physics GA XR754 UT WOS:A1997XR75400040 ER PT J AU Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M Lee, SJ ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Sateck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Efimov, A Frasconi, F Gao, M 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 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 OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Prell, S Sharma, V Gronberg, J Hill, TS Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS AF Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M Lee, SJ ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Sateck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Efimov, A Frasconi, F Gao, M 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 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 OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Prell, S Sharma, V Gronberg, J Hill, TS Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS TI Observation of the decay D-s(+)->omega pi(+) SO PHYSICAL REVIEW LETTERS LA English DT Article ID NONLEPTONIC DECAYS AB Using e(+)e(-) annihilation data collected by the CLEO II detector at CESR, we have observed the decay D-s(+)-->omega pi(+). This final state may be produced through the annihilation decay df the D-s(+), or through final state interactions. We find a branching ratio of Gamma(D-s(+)-->omega pi(+))/Gamma(D-s(+)-->eta pi(+)) = 0.16+/-0.04+/-0.03, where the first error is statistical and the second is systematic. C1 CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. RP Balest, R (reprint author), UNIV COLORADO,BOULDER,CO 80309, USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016; OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587; Bean, Alice/0000-0001-5967-8674; Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900 NR 14 TC 7 Z9 7 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 AUG 25 PY 1997 VL 79 IS 8 BP 1436 EP 1440 DI 10.1103/PhysRevLett.79.1436 PG 5 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400004 ER PT J AU Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Green, J Greenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutheroford, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Green, J Greenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutheroford, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Limits on WWZ and WW gamma couplings from p(p)over-bar->e nu jjX events at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID GAUGE BOSON COUPLINGS; ALPHA-S CALCULATION; PHOTON COUPLINGS; WZ PRODUCTION; COLLISIONS; SEARCH; SECTOR AB We present limits on anomalous WWZ and WW gamma couplings from a search for WW and WZ production in p (p) over bar collisions at root s = 1.8 TeV. We use p (p) over bar --> evjjX events recorded with the DO detector at the Fermilab Tevatron Collider during the 1992-1995 run. The data sample corresponds to an integrated luminosity of 96.0 +/- 5.1 pb(-1). Assuming identical WWZ and WW gamma coupling parameters, the 95% C.L. limits on the CP-conserving couplings are -0.33 < lambda < 0.36 (Delta kappa = 0) and -0.43 < Delta kappa < 0.59 (lambda = 0), for a form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also presented. C1 UNIV ARIZONA,TUCSON,AZ 85721. BOSTON UNIV,BOSTON,MA 02215. BROOKHAVEN NATL LAB,UPTON,NY 11973. BROWN UNIV,PROVIDENCE,RI 02912. UNIV BUENOS AIRES,BUENOS AIRES,DF,ARGENTINA. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF IRVINE,IRVINE,CA 92697. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. CTR BRASILEIRO PESQUISAS FIS,LAFEX,RIO JANEIRO,BRAZIL. CINVESTAV,MEXICO CITY 14000,DF,MEXICO. COLUMBIA UNIV,NEW YORK,NY 10027. UNIV DELHI,DELHI 110007,INDIA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV HAWAII,HONOLULU,HI 96822. UNIV ILLINOIS,CHICAGO,IL 60607. INDIANA UNIV,BLOOMINGTON,IN 47405. IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. KOREA UNIV,SEOUL 136701,SOUTH KOREA. KYUNGSUNG UNIV,PUSAN 608736,SOUTH KOREA. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. MOSCOW MV LOMONOSOV STATE UNIV,MOSCOW,RUSSIA. UNIV NEBRASKA,LINCOLN,NE 68588. NYU,NEW YORK,NY 10003. NORTHEASTERN UNIV,BOSTON,MA 02115. NO ILLINOIS UNIV,DE KALB,IL 60115. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. UNIV OKLAHOMA,NORMAN,OK 73019. PANJAB UNIV,CHANDIGARH 160014,INDIA. MOSCOW HIGH ENERGY PHYS INST,PROTVINO 142284,RUSSIA. PURDUE UNIV,W LAFAYETTE,IN 47907. RICE UNIV,HOUSTON,TX 77005. UNIV ESTADUAL RIO DE JANEIRO,RIO JANEIRO,BRAZIL. UNIV ROCHESTER,ROCHESTER,NY 14627. CE SACLAY,CEA,DAPNIA,SERV PHYS PARTICULES,GIF SUR YVETTE,FRANCE. SEOUL NATL UNIV,SEOUL,SOUTH KOREA. SUNY STONY BROOK,STONY BROOK,NY 11794. TATA INST FUNDAMENTAL RES,THEORET ASTROPHYS GRP,MUMBAI 400005,INDIA. UNIV TEXAS,ARLINGTON,TX 76019. TEXAS A&M UNIV,COLLEGE STN,TX 77843. RP Abbott, B (reprint author), UNIV LOS ANDES,BOGOTA,COLOMBIA. RI Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Klyukhin, Vyacheslav/D-6850-2012; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Kim, Sun Kee/G-2042-2015 OI Sznajder, Andre/0000-0001-6998-1108; Aihara, Hiroaki/0000-0002-1907-5964; Dudko, Lev/0000-0002-4462-3192; Klyukhin, Vyacheslav/0000-0002-8577-6531; De, Kaushik/0000-0002-5647-4489; Belyaev, Alexander/0000-0002-1733-4408; Kim, Sun Kee/0000-0002-0013-0775 NR 31 TC 23 Z9 23 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 AUG 25 PY 1997 VL 79 IS 8 BP 1441 EP 1446 DI 10.1103/PhysRevLett.79.1441 PG 6 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400005 ER PT J AU Decker, C Turner, RE Landen, OL Suter, LJ Amendt, P Kornblum, HN Hammel, BA Murphy, TJ Wallace, J Delamater, ND Gobby, P Hauer, AA Magelssen, GR Oertel, AA Knauer, J Marshall, FJ Bradley, D Seka, W Soures, JM AF Decker, C Turner, RE Landen, OL Suter, LJ Amendt, P Kornblum, HN Hammel, BA Murphy, TJ Wallace, J Delamater, ND Gobby, P Hauer, AA Magelssen, GR Oertel, AA Knauer, J Marshall, FJ Bradley, D Seka, W Soures, JM TI Hohlraum radiation drive measurements on the Omega laser SO PHYSICAL REVIEW LETTERS LA English DT Article ID INERTIAL CONFINEMENT FUSION; HIGH-TEMPERATURES; LIGHT AB Time-resolved drive measurements with thin-walled hohlraum targets on Omega [J.M. Soures et al., Phys. Plasmas 3, 2108 (1996)] are presented and compared with two-dimensional hydrodynamical simulations. For the first time, radiation fluxes are measured through the laser entrance hole instead of through a diagnostic side hole. We find improved agreement between time dependent experiments and simulations using this new technique. In addition, the drive history obtained in this manner correlates well with the drive onto the capsule at target center. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14627. RP Decker, C (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Murphy, Thomas/F-3101-2014 OI Murphy, Thomas/0000-0002-6137-9873 NR 21 TC 50 Z9 51 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 AUG 25 PY 1997 VL 79 IS 8 BP 1491 EP 1494 DI 10.1103/PhysRevLett.79.1491 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400017 ER PT J AU Herrmann, MC Fisch, NJ AF Herrmann, MC Fisch, NJ TI Cooling energetic alpha particles in a Tokamak with waves SO PHYSICAL REVIEW LETTERS LA English DT Article ID INDUCED ALFVEN EIGENMODES; ION-BERNSTEIN WAVES; TOPOLOGY; PLASMAS; ORBITS AB Alpha particles, the by-products of the deuterium-tritium reaction in a tokamak fusion reactor, might be cooled through interactions with waves. Numerical simulations employing two waves, one with frequency about the alpha cyclotron frequency and one at much lower frequency, show the: existence of parameter regimes where more than half of the ct-particle power can be diverted to the waves. RP Herrmann, MC (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 18 TC 44 Z9 44 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 AUG 25 PY 1997 VL 79 IS 8 BP 1495 EP 1498 DI 10.1103/PhysRevLett.79.1495 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400018 ER PT J AU Ocko, BM Wang, JX Wandlowski, T AF Ocko, BM Wang, JX Wandlowski, T TI Bromide adsorption on Ag(001): A potential induced two-dimensional Ising order-disorder transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-DIFFRACTION; PHASE-TRANSITIONS; SURFACE; INTERFACE AB The adsorption of bromide on an Ag(001) electrode has been investigated using in situ x-ray scattering methods. With increasing potential, the bromide undergoes a second order phase transition from a lattice gas to an ordered c(2 x 2) structure. The order parameter is consistent with the 2D Ising model prediction beta = 1/8. A comparison of x-ray and electrochemical measurements indicates significant lateral disorder at low coverages which decreases with increasing coverage. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. UNIV ULM,DEPT ELECTROCHEM,D-89069 ULM,GERMANY. RP Ocko, BM (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. RI Thomas, Wandlowski/C-7251-2009; Wang, Jia/B-6346-2011 NR 24 TC 75 Z9 76 U1 0 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 AUG 25 PY 1997 VL 79 IS 8 BP 1511 EP 1514 DI 10.1103/PhysRevLett.79.1511 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400022 ER PT J AU Henson, BF Wilson, KR Robinson, JM AF Henson, BF Wilson, KR Robinson, JM TI Quantitative measurements of multilayer physical adsorption on heterogeneous surfaces from nonlinear light scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID 2ND-HARMONIC GENERATION; HARMONIC-GENERATION; ICE SURFACES; MOLECULES; KINETICS; TOLUENE AB We present measurements of equilibrium multilayer physical adsorption on porous, heterogeneous ice films using nonlinear light scattering. The dependence of scattering intensity on surface coverage is modeled using the adsorption theory of Brunauer, Emmett, and Teller, and an extension based on the Bragg-Williams formalism. We show that a complete equation of state for an adsorbed species can be experimentally determined within this simple framework. RP Henson, BF (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,LOS ALAMOS,NM 87545, USA. NR 18 TC 3 Z9 3 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 AUG 25 PY 1997 VL 79 IS 8 BP 1531 EP 1534 DI 10.1103/PhysRevLett.79.1531 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400027 ER PT J AU Martin, RL Illas, F AF Martin, RL Illas, F TI Antiferromagnetic exchange interactions from hybrid density functional theory SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSITION-METAL DIMERS; ELECTRONIC-STRUCTURE; CORRELATION-ENERGY; LA2CUO4; FORMALISM; MOLECULES; DYNAMICS; SURFACE; CLUSTER; SOLIDS AB A hybrid theory which combines the full nonlocal ''exact'' exchange interaction with the local spin-density approximation of density-functional theory is shown to lead to marked improvement in the description of antiferromagnetically coupled systems. Semiquantitative agreement with experiment-is found for the magnitude of the coupling constant in La2CuO4, KNiF3, and K2NiF4. The magnitude of the unpaired spin population on the metal site is in excellent agreement with experiment for La2CuO4. C1 UNIV BARCELONA,DEPT QUIM FIS,E-08028 BARCELONA,SPAIN. RP Martin, RL (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,MS B268,LOS ALAMOS,NM 87545, USA. RI Illas, Francesc /C-8578-2011 OI Illas, Francesc /0000-0003-2104-6123 NR 42 TC 230 Z9 230 U1 0 U2 14 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 AUG 25 PY 1997 VL 79 IS 8 BP 1539 EP 1542 DI 10.1103/PhysRevLett.79.1539 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400029 ER PT J AU Wood, RF Chen, KR Leboeuf, JN Puretzky, AA Geohegan, DB AF Wood, RF Chen, KR Leboeuf, JN Puretzky, AA Geohegan, DB TI Dynamics of plume propagation and splitting during pulsed-laser ablation SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTOR THIN-FILMS; MONTE-CARLO SIMULATIONS; YBA2CU3O7-X/PRBA2CU3O7-X SUPERLATTICES; EVAPORATION; LAYERS AB An innovative new approach has been developed for modeling 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. The model is based on a combination of multiple elastic scattering and hydrodynamic formulations. 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 slow component. 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 25 TC 141 Z9 144 U1 0 U2 20 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 AUG 25 PY 1997 VL 79 IS 8 BP 1571 EP 1574 DI 10.1103/PhysRevLett.79.1571 PG 4 WC Physics, Multidisciplinary SC Physics GA XT124 UT WOS:A1997XT12400037 ER PT J AU Aceves, A Holm, DD Kovacic, G Timofeyev, I AF Aceves, A Holm, DD Kovacic, G Timofeyev, I TI Homoclinic orbits and chaos in a second-harmonic generating optical cavity SO PHYSICS LETTERS A LA English DT Article ID 2ND-HARMONIC GENERATION AB We present two large families of Silnikov-type homoclinic orbits in a two-mode model that describes second-harmonic generation in a passive optical cavity. These families of homoclinic orbits give rise to chaotic dynamics in the model. (C) 1997 Published by Elsevier Science B.V. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RENSSELAER POLYTECH INST,DEPT MATH SCI,TROY,NY 12180. RP Aceves, A (reprint author), UNIV NEW MEXICO,DEPT MATH & STAT,ALBUQUERQUE,NM 87131, USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 19 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD AUG 25 PY 1997 VL 233 IS 3 BP 203 EP 208 DI 10.1016/S0375-9601(97)00468-4 PG 6 WC Physics, Multidisciplinary SC Physics GA XW365 UT WOS:A1997XW36500008 ER PT J AU Fuhrmann, M Zhou, H Neiheisel, J Schoonen, MAA Dyer, R AF Fuhrmann, M Zhou, H Neiheisel, J Schoonen, MAA Dyer, R TI Sorption/desorption of radioactive contaminants by sediment from the Kara sea SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article; Proceedings Paper CT 2nd Symposium and International Conference on Environmental Radioactivity in the Arctic CY AUG 21-25, 1995 CL OSLO, NORWAY DE Kara Sea; sediment; radionuclides; sorption; desorption; partition coefficient (K-d) ID SOLIDS CONCENTRATION; AQUATIC SYSTEMS; POLLUTANTS; SORPTION AB To understand the long term impact of the disposal of radioactive waste on the Kara Sea, partition coefficients (K-d) for several important radionuclides, the mineralogy of the sediment, and the relationship of K-d to liquid-to-solid ratio were quantified. Sediment was obtained from four locations in the Kara Sea area. Slow sorption kinetics were observed for Sr-85, U-232, I-125 and Tc-99, whilst sorption was rapid (less than 50 h to steady-state) for Cs-137, Pb-210, and Am-241. Partition coefficients (K-d) were determined using batch type experiments and sorption isotherms which were developed for Sr-85, Tc-99, I-125, U and Cs-137. Partition coefficients for Cs-137 were approx. 350 ml/g for sediment from the Trough and 180 ml/g for Stepovogo Fjord. This difference may be caused by the lower fraction of expandable clay in sediment from the fjord. Uptake of Sr-85, Tc-99, I-125, and U were all similar for both locations, with K-d values averaging 4, 3, 17 and 60 ml/g, respectively. The K-d for Cs-137 varied non-linearly from 40 to 3800 ml/g as the liquid-to-solid ratio varied from 3.4 to 6500, but only when the sorption capacity was high compared to the mass of Cs-137 in the closed system of the experiment. Under identical conditions, sediment with lower K-d values showed no effect. Oxidation of sediment effectively desorbed Tc-99 from the solid phase, whilst it caused increased uptake of Sr-85 and U. In sequential rinses with fresh seawater, desorption was limited to 60% of Cs-137 and Sr-85, and 35% of uranium. (C) 1997 Elsevier Science B.V. C1 US EPA,WASHINGTON,DC 20460. SUNY STONY BROOK,DEPT EARTH & SPACE SCI,STONY BROOK,NY 11794. RP Fuhrmann, M (reprint author), BROOKHAVEN NATL LAB,ENVIRONM & WASTE TECHNOL CTR,BLDG 830,UPTON,NY 11973, USA. RI Schoonen, martin/E-7703-2011 OI Schoonen, martin/0000-0002-7133-1160 NR 23 TC 14 Z9 14 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD AUG 25 PY 1997 VL 202 IS 1-3 BP 5 EP 24 DI 10.1016/S0048-9697(97)00101-0 PG 20 WC Environmental Sciences SC Environmental Sciences & Ecology GA XL739 UT WOS:A1997XL73900002 PM 9241875 ER PT J AU Paluszkiewicz, T Hibler, LF Becker, P Mandych, A Richmond, MC Thomas, S AF Paluszkiewicz, T Hibler, LF Becker, P Mandych, A Richmond, MC Thomas, S TI An assessment of the flux of Sr-90 contamination through the Ob' river and estuary to the Kara sea SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article; Proceedings Paper CT 2nd Symposium and International Conference on Environmental Radioactivity in the Arctic CY AUG 21-25, 1995 CL OSLO, NORWAY DE Ob' River; Mayak; Sr-90; numerical models; estuary; Russia AB The Ob' River system, consisting of the Ob' River drainage and its tributaries, connects the Mayak and Tomsk nuclear facilities to the Kara Sea. The Ob' River system and estuary have been modeled to explore the pathways of transport and the flux of Sr-90. We have also examined the processes controlling the hydrological regime of the Ob' and its tributaries. The simulations demonstrate that Sr-90 levels within the observed ranges can be reproduced along the course of the Ob' River using these coupled models. These simulations indicate that Sr-90 has a residence time of about 200 days in the estuary under high river discharge (1985) conditions, assuming that all of the material is soluble. The coupled models used 1985 river flow data and measured Sr-90 levels along lower portions of the river and throughout the Ob estuary in the simulation of transport and fate. Estimated Sr-90 levels are lower than those observed, because only the Mayak source is included; the portion of the flux due to fallout has not yet been incorporated. Published by Elsevier Science B.V. C1 RUSSIAN ACAD SCI, INST GEOG, MOSCOW 109017, RUSSIA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Paluszkiewicz, T (reprint author), PACIFIC NW LAB, MARINE SCI LAB, 1529 W SEQUIM BAY RD, SEQUIM, WA 98382 USA. NR 30 TC 5 Z9 5 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD AUG 25 PY 1997 VL 202 IS 1-3 BP 43 EP 56 DI 10.1016/S0048-9697(97)00103-4 PG 14 WC Environmental Sciences SC Environmental Sciences & Ecology GA XL739 UT WOS:A1997XL73900004 ER PT J AU Warden, JM Lynn, NM Mount, M Sivintsev, Y Timms, SJ Yefimov, E Gussgard, K Dyer, RS Sjoeblom, KL AF Warden, JM Lynn, NM Mount, M Sivintsev, Y Timms, SJ Yefimov, E Gussgard, K Dyer, RS Sjoeblom, KL TI Potential radionuclide release rates from marine reactors dumped in the Kara Sea SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article; Proceedings Paper CT 2nd Symposium and International Conference on Environmental Radioactivity in the Arctic CY AUG 21-25, 1995 CL OSLO, NORWAY DE radionuclides; marine reactors; computer models; Kara Sea AB The largest inventory of radioactive materials dumped in the Kara Sea by the former Soviet Union comes from the spent nuclear fuel (SNF) of seven marine reactors, the 1994 inventory of which made a total of approximately 4.7 PBq. In progressing its work for the International Arctic Seas Assessment Project (IASAP), under the auspices of the International Atomic Energy Agency (IAEA), the IASAP Source Term Working Group has developed a number of simple computer models to predict the potential release patterns of radionuclides into the Kara Sea from the SNF and activated components dumped within the marine reactors. These models are based on the present and future conditions of the barrier materials and their configuration within the dumped objects. They account for progressive corrosion of the outer and inner steel barriers, breakdown of the organic fillers, and degradation and leaching from the SNFs. Annual release rates are predicted to beyond 5000 years into the future. (C) 1997 Elsevier Science B.V. C1 ROYAL NAVAL COLL GREENWICH,DEPT NUCL SCI & TECHNOL,LONDON SE10 9NN,ENGLAND. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. IV KURCHATOV ATOM ENERGY INST,RUSSIAN RES CTR,MOSCOW 123182,RUSSIA. INST PHYS & POWER ENGN,OBNINSK,RUSSIA. NORWEGIAN RADIAT PROTECT AUTHOR,N-1345 OSTERAS,NORWAY. US EPA,WASHINGTON,DC 20460. INT ATOM ENERGY AGCY,A-1400 VIENNA,AUSTRIA. NR 9 TC 0 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD AUG 25 PY 1997 VL 202 IS 1-3 BP 225 EP 236 DI 10.1016/S0048-9697(97)00118-6 PG 12 WC Environmental Sciences SC Environmental Sciences & Ecology GA XL739 UT WOS:A1997XL73900019 ER PT J AU Aksentijevich, I Centola, M Deng, ZM Sood, R Balow, JE Wood, G Zaks, N Mansfield, E Chen, X Eisenberg, S Vedula, A Shafran, N Raben, N Pras, E Pras, M Kastner, DL Blake, T Baxevanis, AD Robbins, C Krizman, D Collins, FS Liu, PP Chen, XG Shohat, M Hamon, M Kahan, T Cercek, A Rotter, JI FischelGhodsian, N Richards, N Shelton, DA Gumucio, D Yokoyama, Y Mangelsdorf, M Orsborn, A Richards, RI Ricke, DO Buckingham, JM Moyzis, RK Deaven, LL Doggett, NA AF Aksentijevich, I Centola, M Deng, ZM Sood, R Balow, JE Wood, G Zaks, N Mansfield, E Chen, X Eisenberg, S Vedula, A Shafran, N Raben, N Pras, E Pras, M Kastner, DL Blake, T Baxevanis, AD Robbins, C Krizman, D Collins, FS Liu, PP Chen, XG Shohat, M Hamon, M Kahan, T Cercek, A Rotter, JI FischelGhodsian, N Richards, N Shelton, DA Gumucio, D Yokoyama, Y Mangelsdorf, M Orsborn, A Richards, RI Ricke, DO Buckingham, JM Moyzis, RK Deaven, LL Doggett, NA TI Ancient missense mutations in a new member of the RoRet gene family are likely to cause familial Mediterranean fever SO CELL LA English DT Article ID IMMUNODEFICIENCY-VIRUS TYPE-1; PROTEIN SECONDARY STRUCTURE; SHORT ARM; EXPRESSION; CLONING; FINGER; IDENTIFICATION; CHROMOSOME-16; EVOLUTIONARY; AMYLOIDOSIS AB Familial Mediterranean fever (FMF) is a recessively inherited disorder characterized by dramatic episodes of fever and serosal inflammation. This report describes the cloning of the gene likely to cause FMF from a 115-kb candidate interval on chromosome 16p. Three different missense mutations were identified in affected individuals, but not in normals. Haplotype and mutational analyses disclosed ancestral relationships among carrier chromosomes in populations that have been separated for centuries. The novel gene encodes a 3.7-kb transcript that is almost exclusively expressed in granulocytes. The predicted protein, pyrin, is a member of a family of nuclear factors homologous to the Ro52 autoantigen. The cloning of the FMF gene promises to shed light on the regulation of acute inflammatory responses. C1 NIAMSD,ARTHRIT & RHEUMATISM BRANCH,BETHESDA,MD 20892. CHAIM SHEBA MED CTR,HELLER INST MED RES,DEPT MED C,IL-52621 TEL HASHOMER,ISRAEL. NHGRI,CANC GENET LAB,BETHESDA,MD 20892. NHGRI,LAB GENE TRANSFER,BETHESDA,MD 20892. NHGRI,GENOME TECHNOL BRANCH,BETHESDA,MD 20892. CEDARS SINAI MED CTR,DEPT PEDIAT,LOS ANGELES,CA 90048. CEDARS SINAI MED CTR,DEPT MED GENET,LOS ANGELES,CA 90048. BEILINSON MED CTR,DEPT MED GENET,IL-49100 PETAH TIQWA,ISRAEL. UNIV MICHIGAN,DEPT ANAT & CELL BIOL,ANN ARBOR,MI 48109. ADELAIDE WOMENS & CHILDRENS HOSP,DEPT CYTOGENET & MOL GENET,ADELAIDE,SA 5006,AUSTRALIA. LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. RI Liu, Paul/A-7976-2012; Hamon, Melanie/B-3501-2013; Mangelsdorf, Marie/A-2318-2013 OI Liu, Paul/0000-0002-6779-025X; Mangelsdorf, Marie/0000-0002-7855-7701 NR 48 TC 805 Z9 820 U1 1 U2 21 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 SN 0092-8674 J9 CELL JI Cell PD AUG 22 PY 1997 VL 90 IS 4 BP 797 EP 807 PG 11 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA XT066 UT WOS:A1997XT06600022 ER PT J AU Kaess, U Majer, G Stoll, M Peterson, DT Barnes, RG AF Kaess, U Majer, G Stoll, M Peterson, DT Barnes, RG TI Hydrogen and deuterium diffusion in titanium dihydrides/dideuterides SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE NMR studies; titanium dihydrides; hydrogen diffusion; metal hydrides; deuterides ID NUCLEAR MAGNETIC-RESONANCE; TI-H SYSTEM; SPIN RELAXATION; TRANSLATIONAL DIFFUSION; ZIRCONIUM DIHYDRIDES; HYDRIDE; ZRHX; MECHANISM; SOLIDS AB The macroscopic diffusivities Cl of hydrogen in titanium dihydrides, (TiHx)-H-1 (1.65 less than or equal to x less than or equal to 2.02), and of deuterium in titanium dideuterides. (TiHx)-H-2 (x=1.74, 1.98), have been measured by means of pulsed-field-gradient (PFG) nuclear magnetic resonance over wide temperature ranges. The effective activation enthalpy for hydrogen diffusion, H-a(1H), obtained bf fitting an Arrhenius expression to the diffusivities, increases with increasing hydrogen concentration from H-a(1H)=0.55 eV (x=1.65) to H-a(1H)=0.92 eV (x=2.02). The proton spin-lattice relaxation rate Gamma(1), measured on the same samples, reveals also a rapid increase in H-a(1H) for x-->2. The effective activation enthalpy in the deuterides, H-a(2H)=0.60 eV (x=1.74) and H-a(2H)=0.67 eV (x=1.98), depends only weakly on x. A comparison of PFG and Gamma(1) data indicates that hydrogen atoms jump predominantly between adjacent tetrahedral (T) sites. The observed increase in the effective activation enthalpy with increasing x stands in contradiction to published H-a(1H) values based on Gamma(1) or NMR line width data. The literature values H(a)(1H)approximate to 0.50 eV. which reflect primarily measurements at lower temperature and lower x-values, are nearly independent of the hydrogen concentration x. The present studies show, however, that the concentration dependence of the diffusion parameters of hydrogen in TiHx is similar to that in ZrHx, where H-a increases sharply as x approaches the stoichiometric limit. Tf the sublattice formed by the T-sites is almost filled, additional diffusion processes besides the jumps from occupied to empty T-sites must contribute significantly to the hydrogen diffusivity. Several models for such an additional diffusion mechanism are discussed. (C) 1997 Elsevier Science S.A. C1 MAX PLANCK INST MET RES,INST PHYS,D-70569 STUTTGART,GERMANY. IOWA STATE UNIV,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV,US DOE,AMES LAB,AMES,IA 50011. NR 37 TC 28 Z9 28 U1 2 U2 14 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD AUG 22 PY 1997 VL 259 IS 1-2 BP 74 EP 82 DI 10.1016/S0925-8388(97)00124-2 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XX696 UT WOS:A1997XX69600017 ER PT J AU Anderson, JR Kleinke, H Franzen, HF AF Anderson, JR Kleinke, H Franzen, HF TI ZrO2-xSx: Stabilization of cubic ZrO2 by a partial exchange of oxygen by sulfur SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Letter DE fluorite-type zirconia; oxide-sulfide solid solution ID SULFATED ZIRCONIA; CATALYSTS AB The cubic, fluorite-type, structure of zirconia has been found to be stabilized at room-temperature by the substitution of the sulfur for oxygen at 20% of the anion sites in a random way. A major effect of this substitution is to increase the Zr-Zr distances and thereby to decrease the metal-metal interactions contributing to the structural stability of the monoclinic form. (C) 1997 Elsevier Science S.A. C1 IOWA STATE UNIV,AMES LAB,US DOE,AMES,IA 50011. NR 18 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD AUG 22 PY 1997 VL 259 IS 1-2 BP L14 EP L18 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XX696 UT WOS:A1997XX69600004 ER PT J AU Hartland, GV Qin, D Dai, HL Chen, C AF Hartland, GV Qin, D Dai, HL Chen, C TI Collisional energy transfer of highly vibrationally excited NO2: The role of intramolecular vibronic coupling and the transition dipole coupling mechanism SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NITROGEN-DIOXIDE FLUORESCENCE; POLYATOMIC-MOLECULES; DIODE-LASER; EMISSION-SPECTROSCOPY; EXCITATION SPECTRUM; INFRARED-EMISSION; COOLED NO2; DEACTIVATION; CO2; RELAXATION AB The collisional relaxation of highly vibrationally excited NO2 has been studied for a variety of collision partners !He, Ar, CO, N-2, O-2, N2O, NO2, CO2, SF6, and toluene) by time-resolved Fourier transform infrared emission spectroscopy. The average energy [E] of the vibrationally excited NO2 molecules during collisional quenching was obtained from the IR spectra by modeling the upsilon(3) and upsilon(1) + upsilon(3) bands, using the known harmonic frequencies and anharmonicity constants. The average amount of energy lost per collision [Delta E] was determined from the [E] versus time data. The results show that there is a dramatic increase in the amount of energy transferred for all bath gases at NO2 energies above 10 000-12 000 cm(-1), which is near the origin of the NO2 (A) over tilde(2)B(2)/(B) over tilde(2)B(1) states, This threshold in the energy-transfer rate occurs because of strong vibronic coupling between the (X) over tilde(2)A(1) and (A) over tilde(2)B(2)/(B) over tilde(2)B(1) electronic states. The increase in vibration-to-vibration (V-V! energy transfer can be understood within the context of the transition dipole coupling model. Vibronic coupling in NO2 produces extensive broadband emission in the IR and near-IR, which enhances the V-V energy-transfer rate by relaxing the resonance conditions in dipole coupling. The V-V energy-transfer probability was calculated using the dipole coupling model, where the transition dipole moment of excited NO2 was directly extracted from the IR emission spectra. These calculations successfully reproduced the observed threshold in the V-V energy transfer probability. The transition dipole coupling model was also used to estimate the relative contribution of V-V versus vibration-to-translation, rotation (V-T,R) energy transfer for NO2 deactivation. The calculations showed that V-T,R energy transfer is the major relaxation channel for triatomic or smaller collision partners. For larger species like SF6, however, V-V energy transfer is the dominant channel. Vibronic coupling may cause an increase in the V-T,R energy-transfer rate by allowing electronic potential related terms, possibly the electronic transition dipole moment, to contribute to the matrix elements responsible for V-T,R energy transfer. (C) 1997 American Institute of Physics. C1 UNIV PENN,DEPT CHEM,PHILADELPHIA,PA 19104. BROOKHAVEN NATL LAB,DEPT ADV TECHNOL,UPTON,NY 11973. RI Qin, Dong/E-1434-2011; Hartland, Gregory/K-2694-2012 NR 63 TC 43 Z9 43 U1 2 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 22 PY 1997 VL 107 IS 8 BP 2890 EP 2902 DI 10.1063/1.474648 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XR572 UT WOS:A1997XR57200022 ER PT J AU BellissentFunel, MC Tassaing, T Zhao, H Beysens, D Guillot, B Guissani, Y AF BellissentFunel, MC Tassaing, T Zhao, H Beysens, D Guillot, B Guissani, Y TI The structure of supercritical heavy water as studied by neutron diffraction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COMPUTER-SIMULATION; CARBON-DIOXIDE; SCATTERING; LIQUID; TEMPERATURES; FLUCTUATIONS; DETECTOR; STATES AB Neutron diffraction experiments of heavy water at several supercritical states (380860 meters below land surface) terrestrial subsurface. Molecular analyses based on 16S ribosomal RNA (rRNA) gene sequences revealed that some of these bacteria represent an unrecognized phylogenetic group of dissimilatory Fe(III)-reducing bacteria. This discovery adds another dimension to the study of microbial Fe(III) reduction and biogenic magnetism. It also provides examples for understanding the history of Fe(III)-reducing microorganisms and for assessing possible roles of such microorganisms on hot primitive planets. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. UNIV WISCONSIN,DEPT PHYS,MILWAUKEE,WI 53201. RI phelps, tommy/A-5244-2011 NR 54 TC 104 Z9 107 U1 2 U2 23 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD AUG 22 PY 1997 VL 277 IS 5329 BP 1106 EP 1109 DI 10.1126/science.277.5329.1106 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XT033 UT WOS:A1997XT03300038 ER PT J AU Hill, SE Glendening, ED Feller, D AF Hill, SE Glendening, ED Feller, D TI Theoretical study of cation/ether complexes: The alkali metals and dimethyl ether SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN-BASIS SETS; N = 1-4; AB-INITIO; BINDING-ENERGIES; CROWN-ETHERS; GAS-PHASE; MOLECULAR-INTERACTIONS; WATER CLUSTERS; IONS; CATIONS AB The structures and binding enthalpies of a single alkali metal cation complexed with up through four dimethyl ether (DME) ligands were obtained with Hartree-Fock wave functions and second-order perturbation theory, with consideration of core/valence correlation and relativistic effects. The basis sets used in this study included diffuse functions on oxygen, in order to minimize undesirable basis set superposition error, and polarization functions on all non-hydrogen atoms. The observed trends in complex formation energy along the sequence of cations are discussed and compared to the available experimental data obtained from collision-induced dissociation measurements. Minimum energy M+(DME)(2) geometries are predicted to be Linear for the light metal complexes and bent for the heavy metal complexes. RP Hill, SE (reprint author), PACIFIC NW LAB, ENVIRONM MOL SCI LAB, 906 BATTELLE BLVD, MS K1-90, RICHLAND, WA 99352 USA. NR 52 TC 62 Z9 62 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 21 PY 1997 VL 101 IS 34 BP 6125 EP 6131 DI 10.1021/jp971124+ PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XT045 UT WOS:A1997XT04500020 ER PT J AU Bailey, AE Heard, DE Paul, PH Pilling, MJ AF Bailey, AE Heard, DE Paul, PH Pilling, MJ TI Collisional quenching of OH (A(2)Sigma(+), upsilon'=0) by N-2, O-2 and CO2 between 204 and 294 K. Implications for atmospheric measurements of OH by laser-induced fluorescence SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID A2-SIGMA+ OH; TEMPERATURE; MODEL; HO2; OD AB The temperature dependence of the collisional quenching of OH (A 2,,i = O) has been studied in a discharge-flow system between 204 and 294 K for the collision gases N-2, O-2 and CO2. Quenching cross-sections were observed to increase with decreasing temperature, consistent with attractive forces dominating the collision process. For N-2, the cross-section increases from 4.3 +/- 0.1 Angstrom(2) at 294 +/- 1 K to 6.8 +/- 0.2 Angstrom(2) at 204 +/- 1 K, for O-2 from 18.6 +/- 0.6 Angstrom(2) (294 K) to 23.5 + 0.7 Angstrom(2) (204 K) and for CO2 from 62.8 +/- 1.9 Angstrom(2) (292 K) to 75.6 +/- 2.3 Angstrom(2) (204 K). The results are in good agreement with previous determinations, but extend the range to lower temperatures, and are consistent with data obtained at much higher temperatures. The results are also consistent with the cross-section for quenching by air determined at ultra-low temperatures (ca. 25 K) within a supersonic free-jet expansion. A collision complex model incorporating the rotational dependence of quenching using an exponential energy gap law was able to reproduce the data for O-2 and CO2 over the temperature range studied. The experimental results were used to calculate the effective cross-section for quenching of OH (A (2) Sigma(+), OH(A(2) Sigma(+), upsilon' = 0) by air in the range 200-300 K, covering conditions found both in the stratosphere and within the free-jet expansion of instruments used to measure tropospheric OH by low-pressure laser-induced fluorescence. The fluorescence quantum yield was calculated to change by ca. 25% in this range because of changes in quenching rate, directly affecting instrument calibrations and hence their sensitivity for OH detection. C1 UNIV LEEDS,SCH CHEM,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND. SANDIA NATL LABS,COMBUST RES FACIL,DIV 8351,LIVERMORE,CA 94550. NR 25 TC 32 Z9 32 U1 3 U2 12 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD AUG 21 PY 1997 VL 93 IS 16 BP 2915 EP 2920 DI 10.1039/a701582h PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ891 UT WOS:A1997XQ89100041 ER PT J AU Stocking, EM Schwarz, JN Senn, H Salzmann, M Silks, LA AF Stocking, EM Schwarz, JN Senn, H Salzmann, M Silks, LA TI Synthesis of L-selenocystine, L-[Se-77]selenocystine and L-tellurocystine SO JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 LA English DT Article ID MAGNETIC-RESONANCE SPECTROSCOPY; SE-77 NMR-SPECTROSCOPY; DISPOSED CHIRAL CENTERS; DIHYDROFOLATE-REDUCTASE; AMINO-ACIDS; ESCHERICHIA-COLI; OXAZOLIDINE-2-SELONES; PROTEINS; TELLUROMETHIONINE; SELENOSUBTILISIN AB Synthetic routes for the synthesis of stable isotope labelled amino acids which contain either a selenium or a tellurium atom have been explored. L-Selenocystine, L-[Se-77]selenocystine and L-tellurocystine have been constructed in four steps from commercially available methyl (2S)-2-[(tert-butoxycarbonyl)amino]-3-hydroxypropionate. The sequence of reactions has been successfully scaled up giving significant quantities of the chalcogen based amino acids in fair to good overall yield. C1 NIH NATL STABLE ISOTOPE RESOURCE,LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. HOFFMANN LA ROCHE AG,PHARMA RES NEW TECHNOL,CH-4002 BASEL,SWITZERLAND. NR 34 TC 45 Z9 46 U1 1 U2 6 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0300-922X J9 J CHEM SOC PERK T 1 JI J. Chem. Soc.-Perkin Trans. 1 PD AUG 21 PY 1997 IS 16 BP 2443 EP 2447 DI 10.1039/a600180g PG 5 WC Chemistry, Organic SC Chemistry GA XR712 UT WOS:A1997XR71200028 ER PT J AU Arrhenius, G Sales, B Mojzsis, S Lee, T AF Arrhenius, G Sales, B Mojzsis, S Lee, T TI Entropy and charge in molecular evolution - the case of phosphate SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Review ID EARTHS EARLY ATMOSPHERE; CATALYZED PHOSPHORYLATION REACTIONS; CHEMICAL EVOLUTION; ORGANIC-MOLECULES; LIFE; MONTMORILLONITE; HYDROTALCITE; ORIGIN; RNA; SEA AB Biopoesis, the creation of life, implies molecular evolution from simple components, randomly distributed and in a dilute state, to form highly organized, concentrated systems capable of metabolism, replication and mutation. This chain of events must involve environmental processes that can locally lower entropy in several steps; by specific selection from an indiscriminate mixture, by concentration from dilute solution, and in the case of the mineral-induced processes, by particular effectiveness in ordering and selective reaction, directed toward formation of functional biomolecules. Numerous circumstances provide support for the notion that negatively charged molecules were functionally required and geochemically available for biopoesis. Sulfite ion may have been important in bisulfite complex formation with simple aldehydes, facilitating the initial concentration by sorption of aldehydes in positively charged surface active minerals. Berate ion may have played a similar, albeit less investigated role in forming charged sugar complexes. Among anionic species, oligophosphate ions and charged phosphate esters are likely to have been of even more wide ranging importance, reflected in the continued need for phosphate in a proposed RNA world, and extending its central role to evolved biochemistry. Phosphorylation is shown to result in selective concentration by surface sorption of compounds, otherwise too dilute to support condensation reactions. It provides protection against rapid hydrolysis of sugars and, by selective concentration, induces the oligomerization of aldehydes. As a manifestation of life arisen, phosphate already appears in an organic context in the oldest preserved sedimentary record. (C) 1997 Academic Press Limited. C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RP Arrhenius, G (reprint author), UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, LA JOLLA, CA 92093 USA. NR 106 TC 52 Z9 57 U1 0 U2 13 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD AUG 21 PY 1997 VL 187 IS 4 BP 503 EP 522 DI 10.1006/jtbi.1996.0385 PG 20 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA XR804 UT WOS:A1997XR80400006 PM 9299295 ER PT J AU Brucker, J AF Brucker, J TI Depreciating death SO MACHINE DESIGN LA English DT Letter RP Brucker, J (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENTON PUBL INC PI CLEVELAND PA 1100 SUPERIOR AVE, CLEVELAND, OH 44114 SN 0024-9114 J9 MACH DES JI Mach. Des. PD AUG 21 PY 1997 VL 69 IS 16 BP 10 EP 10 PG 1 WC Engineering, Mechanical SC Engineering GA XR493 UT WOS:A1997XR49300004 ER PT J AU Einasto, J Einasto, M Frisch, P Gottlober, S Muller, V Saar, V Starobinsky, AA Tago, E Tucker, D Andernach, H AF Einasto, J Einasto, M Frisch, P Gottlober, S Muller, V Saar, V Starobinsky, AA Tago, E Tucker, D Andernach, H TI The superduster-void network .2. An oscillating cluster correlation function SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies, clusters, general; cosmology, observations; cosmology, theory; large-scale structure of Universe ID ABSORPTION-LINE SYSTEMS; LARGE-SCALE PERIODICITY; POWER-SPECTRUM; RICH CLUSTERS; MPC SCALES; GALAXIES; UNIVERSE; MATTER AB We use rich clusters of galaxies in the Northern and Southern Galactic hemispheres up to a redshift z = 0.12 to determine the cluster correlation function for a separation interval approximate to 650h(-1) Mpc (h is the Hubble constant in units of 100 kms(-1) Mpc(-1)). We show that superclusters of galaxies and voids between them form a moderately regular network. Asa result the correlation function determined for clusters located in rich superclusters oscillates: it has a series of regularly spaced secondary maxima and minima. The scale of the supercluster-void network, determined from the period of oscillations, is P = 115 +/- 15 h(-1) Mpc, Five periods are observed, The correlation function found for clusters in poor and medium-rich superclusters is zero on large scales. The correlation functions calculated separately for the Northern and Southern Galactic hemispheres are similar; only the amplitude of oscillations for clusters in the Southern hemisphere is larger by a factor of about 1.5. We investigate the influence of possible errors in the correlation function. The amplitude of oscillations for clusters in very rich superclusters is about 3 times larger than the estimated error, We argue that the oscillations in the correlation function are due neither to the double-cone shape of the observed volume of space, nor to the inaccuracy in the selection function. We compare the observed cluster correlation function with Similar functions derived for popular models of structure formation, as well as for simple geometrical models of cluster distribution. We find that the production of the observed cluster con;elation function in any model with a smooth transition of the power spectrum from a Harrison-Zeldovich regime with positive spectral index at long wavelengths to a negative spectral index at short wavelengths is highly unlikely. The power spectrum must have an extra peak located at a wavelength equal to the period of oscillations of the correlation function. The relative amplitude of the peak over the smooth spectrum is probably of the order of a factor of at least 1.25. These quantitative tests show that high-density regions in the Universe marked by rich clusters of galaxies are distributed more regularly than expected. Thus our present understanding of structure formation needs revision. C1 GOTTINGEN UNIV OBSERV,D-37083 GOTTINGEN,GERMANY. INST ASTROPHYS,D-14482 POTSDAM,GERMANY. LD LANDAU THEORET PHYS INST,MOSCOW 117334,RUSSIA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IUE OBSERV,ESA,INSA,E-28080 MADRID,SPAIN. UNIV GUANAJUATO,DEPT ASTRON,GUANAJUATO,MEXICO. RP Einasto, J (reprint author), TARTU ASTROPHYS OBSERV,EE-2444 TORAVERE,ESTONIA. OI Starobinsky, Alexei/0000-0002-8946-9088 NR 33 TC 48 Z9 48 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 21 PY 1997 VL 289 IS 4 BP 801 EP 812 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XU946 UT WOS:A1997XU94600008 ER PT J AU Einasto, J Einasto, M Frisch, P Gottlober, S Muller, V Saar, V Starobinsky, AA Tucker, D AF Einasto, J Einasto, M Frisch, P Gottlober, S Muller, V Saar, V Starobinsky, AA Tucker, D TI The superduster-void network .3. The correlation function as a geometrical statistic SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods, numerical; galaxies, clusters, general; cosmology, theory; large-scale structure of Universe ID RICH CLUSTERS; GALAXIES; UNIVERSE; SCALE; SUPERCLUSTERS; ANISOTROPIES; MATTER; MODELS AB We investigate properties of the correlation function of clusters of galaxies using geometrical models. We show that the correlation function contains useful information on the geometry of the distribution of clusters. On small scales the correlation function depends on the shape and the size of superclusters. On large scales it describes the geometry of the distribution of superclusters. If superclusters are distributed randomly then the correlation function on large scales is featureless. If superclusters have a quasi-regular distribution then this regularity can be detected and measured by the correlation function. Superclusters of galaxies separated by large voids produce a correlation function with a minimum which corresponds to the mean separation between centres of superclusters and voids, followed by a secondary maximum corresponding to the distance between superclusters across voids. If superclusters and voids have a tendency to form a regular lattice then the correlation function on large scales has quasi-regularly spaced maxima and minima of decaying amplitude; i.e. it is oscillating. The period of oscillations is equal to the step size of the grid of the lattice. We also calculate the power spectrum and the void diameter distribution for our models and compare the geometrical information of the correlation function with other statistics. We find that geometric properties (the regularity of the distribution of clusters on large scales) are better quantified by the correlation function. We also analyse errors in the correlation function and the power spectrum by generating random realizations of models and finding the scatter of these realizations. C1 GOTTINGEN UNIV OBSERV,D-37083 GOTTINGEN,GERMANY. INST ASTROPHYS,D-14482 POTSDAM,GERMANY. LD LANDAU THEORET PHYS INST,MOSCOW 117334,RUSSIA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP Einasto, J (reprint author), TARTU OBSERV,EE-2444 TORAVERE,ESTONIA. OI Starobinsky, Alexei/0000-0002-8946-9088 NR 28 TC 22 Z9 22 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 21 PY 1997 VL 289 IS 4 BP 813 EP 823 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XU946 UT WOS:A1997XU94600009 ER PT J AU Beuville, E Beche, JF Cork, C Douence, V Earnest, T Millaud, J Nygren, D Padmore, H Turko, B Zizka, G Datte, P Xuong, NH AF Beuville, E Beche, JF Cork, C Douence, V Earnest, T Millaud, J Nygren, D Padmore, H Turko, B Zizka, G Datte, P Xuong, NH TI A 16 x 16 pixel array detector for protein crystallography SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 3rd International Workshop on Semiconductor Pixel Detectors for Particles and X-rays CY MAR 24-27, 1996 CL BARI, ITALY AB A 2D pixel array detector prototype is being designed for static and time resolved protein crystallography. This pixel detector will significantly enhance time resolved Laue protein crystallography by two or three orders of magnitude compared to existing sensors such as films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow to study structural changes that occur within the protein as a function of time (concurrent readout and acquisition). The prototype consists of an array of 16 X 16 pixels of 150 x 150 mu m(2) size. The individual pixel processor consists of a low-noise amplifier shaper followed by a differential threshold comparator which provides the counting of individual photons with energies above a programmable threshold. To accommodate the very high rates, above 5 X 10(8)/cm(2)/s, each pixel processor has a 3 bit pre-scaler which divides the event rate by 8. Overflow from the divider which defines a pseudo fourth bit will generate a readout sequence providing the pixel address. Addresses, generated locally as quantified analog signals, will be used to increment a location in an histogramming memory from which the computerized image of the Laue diagram will be generated. C1 UNIV CALIF SAN DIEGO,LA JOLLA,CA 94093. RP Beuville, E (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 5 TC 7 Z9 7 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 AUG 21 PY 1997 VL 395 IS 3 BP 429 EP 434 DI 10.1016/S0168-9002(96)01234-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XW946 UT WOS:A1997XW94600025 ER PT J AU Pullia, A Kraner, HW Furenlid, L AF Pullia, A Kraner, HW Furenlid, L TI New results with silicon pad detectors and low-noise electronics for absorption spectrometry SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 3rd International Workshop on Semiconductor Pixel Detectors for Particles and X-rays CY MAR 24-27, 1996 CL BARI, ITALY AB High-resistivity silicon diode detectors integrable in array structures have been tested for high-resolution X-ray spectroscopy at various temperatures. Using an inexpensive commercially available front-end transistor we have obtained resolutions of 19 electrons rms, or 165 eV FWHM, at -35 degrees C and 39 electrons rms, or 320 eV FWHM, at 26 degrees C, with 3 and 1 mu s shaping times. The obtained resolution values are adequate for synchrotron light based EXAFS experiments. These reliable detectors can be suitably employed for high-performance multichannel systems in which high-rate capability is achieved by using an array of detectors operated in parallel. A 16-element detector prototype has been recently assembled, installed and successfully operated for a real EXAFS experiment at NSLS. C1 BROOKHAVEN NATL LAB,INSTRUMENTAT DIV,UPTON,NY 11973. BROOKHAVEN NATL LAB,NSLS DIV,UPTON,NY 11973. RP Pullia, A (reprint author), POLITECN MILAN,DIPARTIMENTO ELETTRON & INFORMAZ,PIAZZA L DA VINCI 32,I-20133 MILAN,ITALY. OI Pullia, Alberto/0000-0002-6393-747X NR 8 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 AUG 21 PY 1997 VL 395 IS 3 BP 452 EP 456 DI 10.1016/S0168-9002(97)00606-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XW946 UT WOS:A1997XW94600029 ER PT J AU London, D Soni, A AF London, D Soni, A TI Measuring the CP angle beta in hadronic b->s penguin decays SO PHYSICS LETTERS B LA English DT Article ID CHANGING NEUTRAL CURRENTS; KOBAYASHI-MASKAWA MATRIX; B0 DECAYS; ISOSPIN ANALYSIS; ASYMMETRIES; PHYSICS; PHASE AB Asymmetric e(+)e(-) colliders running on the Y(4S) (B factories) will much more readily measure CP-violating asymmetries in the decays of B-d(0) and B+/- mesons than in the decays of B-s(0) mesons. As such, they will seemingly not be able to probe new phases in [GRAPHICS] mixing, i.e. in b --> s transitions. However, by measuring the CP angle beta via b --> s hadronic penguin decays such as [GRAPHICS] and comparing its value to that obtained in [GRAPHICS] it is possible to detect the presence of new physics in the b --> s flavor-changing neutral current. Recent CLEO results are encouraging in this regard. They suggest that the branching ratio of the b --> s penguin decay B-d(0) --> eta'K-s is anomalously large, about 4 x 10(-5), which will make it much easier to search for new physics in b --> s transitions. (C) 1997 Published by Elsevier Science B.V. C1 BROOKHAVEN NATL LAB,THEORY GRP,UPTON,NY 11973. RP London, D (reprint author), UNIV MONTREAL,PHYS NUCL LAB,CP 6128,SUCC CTR VILLE,MONTREAL,PQ H3C 3J7,CANADA. NR 28 TC 175 Z9 174 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 AUG 21 PY 1997 VL 407 IS 1 BP 61 EP 65 DI 10.1016/S0370-2693(97)00695-3 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP702 UT WOS:A1997XP70200011 ER PT J AU Bhat, PC Prosper, HB Snyder, SS AF Bhat, PC Prosper, HB Snyder, SS TI Bayesian analysis of multi-source data SO PHYSICS LETTERS B LA English DT Article DE Bayesian analysis; data analysis; binned fitting; likelihood; multi-source data; top quark mass ID TOP-QUARK AB We present a simple method, based on Bayes' theorem, to fit binned data to one or more multi-source models. Assuming a Poisson probability for the count in each bin we can eliminate exactly the nuisance parameters from the likelihood function and arrive at a formula that can be broadly applied. We illustrate the method by showing how it can be used to estimate the top quark mass. (C) 1997 Published by Elsevier Science B.V. C1 FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Bhat, PC (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 7 TC 17 Z9 17 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 AUG 21 PY 1997 VL 407 IS 1 BP 73 EP 78 DI 10.1016/S0370-2693(97)00723-5 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP702 UT WOS:A1997XP70200013 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 Greene, R Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L DiCorato, 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 OReilly, 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 Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Grim, GP Link, JM Paolone, VS Yager, PM Wilson, JR Cao, J Hosack, M Hughes, J Sheldon, PD Davenport, F Danyo, K Handler, T Cheon, BG Chung, YS Kang, J 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 Greene, R Rahimi, A Wiss, J Alimonti, G Bellini, G Boschini, M Brambilla, D Caccianiga, B Cinquini, L DiCorato, 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 OReilly, 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 Montiel, E Olaya, D Ramirez, E Rivera, C Zhang, Y Grim, GP Link, JM Paolone, VS Yager, PM Wilson, JR Cao, J Hosack, M Hughes, J Sheldon, PD Davenport, F Danyo, K Handler, T Cheon, BG Chung, YS Kang, J Kim, KY Lee, KB Myung, SS TI Analysis of the D+, D-s(+)->pi(-)pi(+)pi(+) Dalitz plots SO PHYSICS LETTERS B LA English DT Article ID DECAYS AB An amplitude analysis of the D+, D-s(+) --> pi(-)pi(+)pi(+) Dalitz plots is presented using data collected by the Fermilab high-energy photoproduction experiment E687. The data are fitted to a model consisting of a sum of relativistic Breit-Wigner amplitudes for the intermediate two-body resonant decay modes plus a flat non-resonant contribution. From the fit we derive decay fractions and relative phases. We also present measurements of Gamma(D+-->pi(-)pi(+)pi(+))/Gamma(D+-->K(-)pi(+)pi(+)) and Gamma(D-s(+)-->pi(-)pi(+)pi(+))/Gamma(D-s(+)-->K(-)K(+)pi(+)). (C) 1997 Published by Elsevier Science B.V. C1 IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. UNIV COLORADO,BOULDER,CO 80309. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV ILLINOIS,URBANA,IL 61801. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. IST NAZL FIS NUCL,I-20133 MILAN,ITALY. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. UNIV PAVIA,DIPARTIMENTO FIS NUCL & TEOR,I-27100 PAVIA,ITALY. IST NAZL FIS NUCL,I-27100 PAVIA,ITALY. UNIV PUERTO RICO,MAYAGUEZ,PR. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV S CAROLINA,COLUMBIA,SC 29208. VANDERBILT UNIV,NASHVILLE,TN 37235. UNIV N CAROLINA,ASHEVILLE,NC 28804. UNIV TENNESSEE,KNOXVILLE,TN 37996. KOREA UNIV,SEOUL 136701,SOUTH KOREA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP Frabetti, PL (reprint author), UNIV BOLOGNA,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. RI Bonomi, Germano/G-4236-2010; Link, Jonathan/L-2560-2013; Menasce, Dario Livio/A-2168-2016; Gianini, Gabriele/M-5195-2014; OI Bonomi, Germano/0000-0003-1618-9648; Link, Jonathan/0000-0002-1514-0650; Boschini, Matteo Jeroen/0000-0002-6401-0457; Menasce, Dario Livio/0000-0002-9918-1686; Gianini, Gabriele/0000-0001-5186-0199; bianco, stefano/0000-0002-8300-4124 NR 14 TC 48 Z9 48 U1 0 U2 6 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 AUG 21 PY 1997 VL 407 IS 1 BP 79 EP 91 DI 10.1016/S0370-2693(97)00726-0 PG 13 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XP702 UT WOS:A1997XP70200014 ER PT J AU Taatjes, CA Oh, DB AF Taatjes, CA Oh, DB TI Time-resolved wavelength modulation spectroscopy measurements of HO2 kinetics SO APPLIED OPTICS LA English DT Article ID SALT DIODE-LASER; LIMITED FM-SPECTROSCOPY; FREQUENCY-MODULATION; BAND STRENGTH; CHEMISTRY; NU-1 AB High-frequency wavelength modulation spectroscopy (WMS) has been applied to the detection of the hydroperoxyl radical (HO2) in a laser photolysis and long-path absorption pump-probe kinetics reactor with a near-infrared distributed feedback diode laser. The HO2 is formed by the 355-nm photolysis of Cl-2 in the presence of CH3OH and O-2 and monitored by a phase-sensitive detection of the second-harmonic (2f) signal in the 2 upsilon(1) band with a 1.5-mu m diode laser directly modulated at 5 MHz. The measured 2fWMS signal is calibrated by direct absorption and converted to an absolute number density with the known absorption line strength of the HO2 line at 6625.80 cm(-1). The utility of time-resolved WMS as a second-order kinetics probe is demonstrated through the measurement of the HO2 self-reaction rate constant at 295 K. (C) 1997 Optical Society of America. C1 SW SCI INC,SANTA FE,NM 87505. RP Taatjes, CA (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,MAIL STOP 9055,LIVERMORE,CA 94551, USA. NR 21 TC 30 Z9 30 U1 3 U2 13 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 20 PY 1997 VL 36 IS 24 BP 5817 EP 5821 DI 10.1364/AO.36.005817 PG 5 WC Optics SC Optics GA XR271 UT WOS:A1997XR27100001 PM 18259411 ER PT J AU Keto, E Hora, JL Deutsch, L Hoffman, W Fazio, GG Ball, R Meixner, M Skinner, C Arens, JF Jernigan, G AF Keto, E Hora, JL Deutsch, L Hoffman, W Fazio, GG Ball, R Meixner, M Skinner, C Arens, JF Jernigan, G TI The infrared bright nuclei in the mid-infrared SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (NGC 6240, IRAS 0518-25, Arp 299); galaxies nuclei; galaxies, starburst; infrared, galaxies ID SHOCKED MOLECULAR-HYDROGEN; STAR FORMATION; GALAXY NGC-6240; STARBURST GALAXIES; MICRON EMISSION; IRAS GALAXIES; ARP 220; GAS; MARKARIAN-231; RESOLUTION AB We present arcsecond angular-resolution mid-IR images of three IR-bright galaxies, NGC 6240, IRAS 0518-25, and the NGC 3690-IC 694 (Arp 299) system, and we compare the sizes of their emission regions in the mid-IR and near-IR, In all these galaxies, most (similar to 75%) of the mid-IR flux, as measured in the IRAS 12 mu m observations, is found in our images to be concentrated within the central few hundred parsecs. Hn the two galaxies which shaw a single IB source in the nucleus, IRAS 0518-25 and IC 694, the mid-IR emission is more compact than the near-IR. This suggests that the mid-IR source, warm dust heated by an active galactic nucleus or an unresolved starburst, is more compact than the population of cooler, older stars. In the two galaxies which show double sources in the nucleus, the reverse is the case, That is, the mid-IR is more extended than the near-IR. Similar results are obtained for a handful of other galaxies for which we have high-resolution mid-IR data, Thus in our small sample, the double source nuclei contain starbursts which are more extended than the older stars and the single source nuclei do not. Some of the double sources seen in the IR bright galaxies, for example NGC 3690, are probably starbursts in conjunction with a galactic nucleus rather than twin galactic nuclei. C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. BOSTON UNIV,DEPT ASTRON,BOSTON,MA 02215. UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. UNIV ILLINOIS,URBANA,IL 61801. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. RP Keto, E (reprint author), SMITHSONAIN ASTROPHYS OBSERV,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. OI Hora, Joseph/0000-0002-5599-4650 NR 46 TC 16 Z9 16 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1997 VL 485 IS 2 BP 598 EP 604 DI 10.1086/304437 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XT240 UT WOS:A1997XT24000013 ER PT J AU Nugent, P Baron, E Branch, D Fisher, A Hauschildt, PH AF Nugent, P Baron, E Branch, D Fisher, A Hauschildt, PH TI Synthetic spectra of hydrodynamic models of type Ia supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; stars, interiors; supernovae, general ID WHITE-DWARF MODELS; RADIATIVE-TRANSFER; EXPANDING SHELLS; HELIUM SHELLS; DETONATION AB We present detailed non-LTE synthetic spectra of hydrodynamic supernovae (SNe) Ia models. We make no assumptions about the form of the spectrum at the inner boundary, We calculate both Chandrasekhar-mass deflagration models and sub-Chandrasekhar ''helium detonators.'' Gamma-ray deposition is handled in a simple, accurate manner. We have parameterized the storage of energy, which arises from the time-dependent deposition of radioactive decay energy, in a reasonable manner that spans the expected range. We find that the Chandrasekhar-mass deflagration model W7 of Nomoto, Thielemann, & Yokoi shows good agreement with the observed spectra of SN 1992A and SN 1994D, particularly in the UV, where our models are expected to be most accurate. The sub-Chandrasekhar models do not reproduce the UV deficit observed in normal SNe Ia They do bear some resemblance to subluminous SNe Ia, but the shapes of the spectra (i.e., the colors) are opposite that of the observed ones, and the intermediate-mass element lines (such as Si II and Cst II) are extremely weak, which seems to be a generic difficulty of the models. Although the sub-Chandrasekhar models have a significant helium abundance (unlike Chandrasekhar-mass models), helium lines are not prominent in the spectra near maximum light and thus do not act as a spectral signature for the progenitor. C1 UNIV OKLAHOMA, DEPT PHYS & ASTRON, NORMAN, OK 73019 USA. UNIV GEORGIA, DEPT PHYS & ASTRON, ATHENS, GA 30602 USA. ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. RP Nugent, P (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, 1 CYCLOTRON RD, MAIL STOP 50-232, BERKELEY, CA 94720 USA. RI Baron, Edward/A-9041-2009 OI Baron, Edward/0000-0001-5393-1608 NR 38 TC 165 Z9 166 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1997 VL 485 IS 2 BP 812 EP 819 DI 10.1086/304459 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XT240 UT WOS:A1997XT24000030 ER PT J AU Jefferson, A Eisele, FL Ziemann, PJ Weber, RJ Marti, JJ McMurry, PH AF Jefferson, A Eisele, FL Ziemann, PJ Weber, RJ Marti, JJ McMurry, PH TI Measurements of the H2SO4 mass accommodation coefficient onto polydisperse aerosol SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFURIC-ACID; VAPOR-PRESSURE; NUCLEATION AB The loss rate of H2SO4 vapor onto submicron particles was measured for three different particle substrates. The experimental technique involved direct flow tube measurements of H2SO4 decay rates onto a polydisperse aerosol using chemical ionization mass spectroscopic detection. The aerosols of this study were partially hydrated crystalline salts with diameters in the size range of 20 to 400 nm. The mass accommodation coefficients, alpha, were calculated from the first-order rate constants for H2SO4 loss to be 0.73=/-0.21 and 0.79+/-0.23 for loss onto (NH4)(2)SO4 and NaCl, respectively. Measurements of the loss rate of H2SO4 onto a NaCl aerosol coated with stearic acid resulted in lower mass accommodation coefficients with values of 0.31 and 0.19 for aerosol with high and low stearic acid coverage, respectively. The observed decrease in alpha on an aerosol with a hydrocarbon coating suggests that aerosol composition is a key factor in H2SO4 adsorption on to a particle surface. C1 COMPUTAT PHYS INC, FAIRFAX, VA 22031 USA. UNIV MINNESOTA, DEPT MECH ENGN, PARTICLE TECHNOL LAB, MINNEAPOLIS, MN 55455 USA. US DOE, BROOKHAVEN NATL LAB, ENVIRONM SCI LAB, UPTON, NY 11973 USA. UNIV CALIF RIVERSIDE, STATEWIDE AIR POLLUT RES CTR, RIVERSIDE, CA 92521 USA. UNIV CALIF RIVERSIDE, DEPT SOIL & ENVIRONM SCI, RIVERSIDE, CA 92521 USA. GEORGIA INST TECHNOL, GEORGIA RES INST, ATLANTA, GA 30332 USA. RP NATL CTR ATMOSPHER RES, DIV ATMOSPHER CHEM, POB 3000, BOULDER, CO 80307 USA. RI Jefferson, Anne/K-4793-2012; McMurry, Peter/A-8245-2008 OI McMurry, Peter/0000-0003-1609-5131 NR 31 TC 66 Z9 66 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1997 VL 102 IS D15 BP 19021 EP 19028 DI 10.1029/97JD01152 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100017 ER PT J AU Heller, J Laws, DD Tomaselli, M King, DS Wemmer, DE Pines, A Havlin, RH Oldfield, E AF Heller, J Laws, DD Tomaselli, M King, DS Wemmer, DE Pines, A Havlin, RH Oldfield, E TI Determination of dihedral angles in peptides through experimental and theoretical studies of alpha-carbon chemical shielding tensors SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; PROTEIN-STRUCTURE DETERMINATION; C-13 NMR-SPECTRA; SOLID-STATE NMR; MAGIC-ANGLE; SHIFT-ANISOTROPY; L-ALANINE; ROTATIONAL RESONANCE; STRUCTURE REFINEMENT; CRYSTAL-STRUCTURE AB A simple method for the determination of backbone dihedral angles in peptides and proteins is presented. The chemical-shift anisotropies (CSA) of the central alanine alpha-carbon in powdered crystalline tripeptides, whose structures have been determined previously by X-ray crystallography, were measured by cross-polarization magic-angle-spinning nuclear magnetic resonance. The experimental CSA values were correlated with ab initio chemical-shielding calculations over Ramanchandran phi/psi space on an N-formyl-L-alanine amide fragment. Using this correlation, phi/psi probability surfaces for one of the tripeptides were calculated based only on the alpha-carbon CSA, allowing a prediction of backbone angles. Dihedral angles predicted by these calculations fall within +/-12 degrees of the values determined by crystallography. This approach should be useful in the determination of solid-slate protein structure. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,GRAD GRP BIOPHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,HOWARD HUGHES MED INST,DEPT MOL & CELL BIOL,BERKELEY,CA 94720. UNIV ILLINOIS,DEPT CHEM,URBANA,IL 61801. NR 57 TC 93 Z9 95 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD AUG 20 PY 1997 VL 119 IS 33 BP 7827 EP 7831 DI 10.1021/ja970124k PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA XT037 UT WOS:A1997XT03700025 ER PT J AU White, JW Zhu, PW Epperson, JE Wozniak, D Snyder, RG AF White, JW Zhu, PW Epperson, JE Wozniak, D Snyder, RG TI Isotope effects on the microphase separation of paraffin mixtures SO MOLECULAR PHYSICS LA English DT Article ID SOLID-SOLUTIONS; LENGTH AB Isotopic sensitivity is reported in both the formation and the above ambient temperature annealing behaviour of lamellar microphases in C-30:C-36 paraffin solid solutions. The time resolved small angle neutron scattering from a 1:1 C30H62:C36D74 mixture and its complementary pair 1:1 C30D62:C36H74 has been studied. Upon quenching such mixtures from the melt; the solid solution so formed nucleates spontaneously to a 'long period' microphase. The two systems differ in that for 1:1 C30D62:C36H74 there is also strong diffraction at Q = 0.136 Angstrom(-1) associated with C36H74 enrichment of the solid solution or a separate phase. Both processes are sensitive to the isotopic composition of the mixture. For both systems the long period scattering from a quenched liquid mixture develops in periods of hours at ambient temperature. Heating the aged microphase structures to temperatures above about 43 degrees C causes them to disappear, but again isotropic sensitivity is noted. It is concluded that the effects are largely kinetic in origin, in agreement with earlier IR studies on intralamellar microaggregation in this system. C1 ARGONNE NATL LAB,DIV MAT PHYS,ARGONNE,IL 60439. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP White, JW (reprint author), AUSTRALIAN NATL UNIV,RES SCH CHEM,POB 414,CANBERRA,ACT 2610,AUSTRALIA. NR 22 TC 10 Z9 10 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD AUG 20 PY 1997 VL 91 IS 6 BP 1017 EP 1024 DI 10.1080/002689797170770 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XR696 UT WOS:A1997XR69600004 ER PT J AU White, JW Wei, ZP Epperson, JE Snyder, RG AF White, JW Wei, ZP Epperson, JE Snyder, RG TI The mechanism of microphase separation in paraffin hydrocarbon mixtures SO MOLECULAR PHYSICS LA English DT Article ID SOLID-SOLUTIONS; SCATTERING; ISOTOPE AB To understand further the mechanism of microphase separation in paraffin mixtures at room temperature the strong small angle neutron scattering from the forming and annealing microphases is reported for a range of concentrations and at a sequence of times after quenching the molten mixtures. The data are very sensitive to the longitudinal organization of the structures and thus are complementary to recent spectroscopic studies. The data for solutions of C-36/C-30 aliphatic hydrocarbons identify scattering from a phase rich in the C-36 component (near Q = similar to 0.1 Angstrom(-1)) and 'long period' scattering whose principal wavevector is concentration dependent. Long periods between 80 Angstrom and similar to 210 Angstrom are observed. The rate and extent of growth of the microphase depend on both composition and quench temperature. The rate of microphase growth at room temperature increases by a factor of about seven times in changing composition from 4:1 C30H62:C36D74 to 1:1 C30H62:C36D74. The data are consistent with a mechanism in which the free energy is minimized by crystal vacancy (even void) elimination and molecular conformational ordering with time as the system enthalpy is minimized by the preferred packing of chains of the same length. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP White, JW (reprint author), AUSTRALIAN NATL UNIV,RES SCH CHEM,POB 414,CANBERRA,ACT 2610,AUSTRALIA. NR 22 TC 11 Z9 11 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD AUG 20 PY 1997 VL 91 IS 6 BP 1039 EP 1058 DI 10.1080/002689797170798 PG 20 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XR696 UT WOS:A1997XR69600006 ER PT J AU Sakaguchi, K Sakamoto, H Lewis, MS Anderson, CW Erickson, JW Appella, E Xie, D AF Sakaguchi, K Sakamoto, H Lewis, MS Anderson, CW Erickson, JW Appella, E Xie, D TI Phosphorylation of serine 392 stabilizes the tetramer formation of tumor suppressor protein p53 SO BIOCHEMISTRY LA English DT Article ID DNA-BINDING FUNCTION; CELL-CYCLE CHECKPOINTS; CASEIN KINASE-II; OLIGOMERIZATION DOMAIN; STRUCTURAL STABILITY; CALORIMETER; SEQUENCES; ACTIVATE; REGIONS; MUTANTS AB Tumor suppressor protein p53 is a tetrameric phosphoprotein that activates transcription from several cell cycle regulating genes in response to DNA damage. Tetramer formation is critical to p53's ability to activate transcription; however, posttranslational modifications and protein stabilization also contribute to p53's ability to activate transcription. To determine if phosphorylation affects tetramer formation, we synthesized phosphopeptides corresponding to residues 303-393 of human p53, which includes the domain responsible for tetramer formation, Phosphate was chemically incorporated at Ser315, Ser378, or Ser392 and also at both Ser315 and Ser392. Equilibrium ultracentrifugal analyses showed that phosphorylation at Ser392 increased the association constant for reversible tetramer formation nearly 10-fold. Phosphorylation of either Ser315 or Ser378 had little effect on tetramer formation, but phosphorylation of Ser315 largely reversed the effect of phosphorylation at Ser392. Analyses by calorimetry demonstrated that phosphorylation may influence subunit affinity (and, in turn, DNA binding) by an enthalpy-driven process, possibly between the C-terminal residues and the region immediately adjacent to Ser315. The K-d for the tetramer-monomer transition of the unphosphorylated p53 C-terminal domain was determined to be similar to 1-10 mu M. Thus, in normal, undamaged cells p53 may be largely monomeric. Enhancement of tetramer formation through phosphorylation of Ser392, coupled with a DNA-damage-induced increase in its nuclear concentration, could provide a switch that activates p53 as a transcription factor in response to DNA damage. C1 NIH,NATL CTR RES RESOURCES,BIOMED ENGN & INSTRUMENTAT PROGRAM,BETHESDA,MD 20892. BROOKHAVEN NATL LAB,UPTON,NY 11973. NCI,FREDERICK CANC RES & DEV CTR,STRUCT BIOCHEM PROGRAM,FREDERICK,MD 21702. RP Sakaguchi, K (reprint author), NCI,CELL BIOL LAB,NIH,BLDG 37,BETHESDA,MD 20892, USA. RI Sakamoto, Hiroshi/A-3181-2011 NR 47 TC 194 Z9 196 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 19 PY 1997 VL 36 IS 33 BP 10117 EP 10124 DI 10.1021/bi970759w PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XR735 UT WOS:A1997XR73500019 PM 9254608 ER PT J AU Luebke, KJ Landry, SM Tinoco, I AF Luebke, KJ Landry, SM Tinoco, I TI Solution conformation of a five-nucleotide RNA bulge loop from a group I intron SO BIOCHEMISTRY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; CONTAINING DEOXYTRIDECANUCLEOTIDE DUPLEXES; TERTIARY STRUCTURE; DEOXYOLIGONUCLEOTIDE DUPLEX; TETRAHYMENA RIBOZYME; ENERGY MINIMIZATION; FLANKING SEQUENCE; NMR-SPECTROSCOPY; MELTING CURVES; DNA DUPLEX AB We present the solution conformation, determined by NMR spectroscopy, of a five-nucleotide RNA bulge loop. The bulge interrupts the stem of a 25-nucleotide RNA hairpin, and its sequence and flanking sequences are those of a conserved bulge from a Group I intron. The secondary structure of the bulge loop in the hairpin context is that predicted by the secondary structure prediction algorithm of Zuker. It differs, however, from the secondary structure deduced from sequence covariation of the bulge in the context of the functionally folded Group I introns and observed in the crystal structure of an independently folding domain of the Group I intron from Tetrahymena thermophila. This difference represents an exception to the heierarchical model of RNA folding in which preformed elements of secondary structure interact to form a tertiary structure. The three-dimensional structure of the bulge loop is characterized by discontinuous base stacking. Adjacent adenines stack with each other and with the flanking double helices, However, the position elf the central uracil is not well defined by NOE distance constraints and is a point of discontinuity in the base stacking. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. FU NIGMS NIH HHS [GM 10840, T32 GM08295] NR 65 TC 26 Z9 26 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 19 PY 1997 VL 36 IS 33 BP 10246 EP 10255 DI 10.1021/bi9701540 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XR735 UT WOS:A1997XR73500034 PM 9254623 ER PT J AU Gold, LS Stern, BR Slone, TH Brown, JP Manley, NB Ames, BN AF Gold, LS Stern, BR Slone, TH Brown, JP Manley, NB Ames, BN TI Pesticide residues in food: investigation of disparities in cancer risk estimates SO CANCER LETTERS LA English DT Article DE cancer risk; pesticide residues; exposure assessment; carcinogenic potency; setting priorities ID CARCINOGENIC POTENCY; CHEMICAL CARCINOGENESIS; RODENT CARCINOGENS; TOTAL DIET; ELEMENTS AB Much of the public perceives that exposure to synthetic pesticide residues in the diet is a major cause of cancer. The National Research Council (NRC), in a 1987 report, Regulating Pesticides in Food: The Delaney Paradox, evaluated cancer risks for 29 pesticides that are rodent carcinogens and estimated that the risks for 23 were greater than one-in-a-million. In contrast, our group has ranked possible carcinogenic hazards from a variety of human exposures to rodent carcinogens using the HERP (Human Exposure/Rodent Potency) index, and found that dietary residues of synthetic pesticides ranked low. This paper evaluates the disparities in these analyses by examining the two components of risk assessment: carcinogenic potency in rodents and human exposure. Potency estimates based on rodent bioassay data are shown to be similar whether calculated, as in the NRC report, as the regulatory q(1)* or as TD50. In contrast, estimates of dietary exposure to residues of synthetic pesticides vary enormously, depending on whether they are based on the Theoretical Maximum Residue Contribution (TMRC) calculated by the Environmental Protection Agency vs. the average dietary residues measured by the Food and Drug Administration in the Total Diet Study (TDS). The TMRC is the theoretical maximum human exposure anticipated under the most severe field application conditions, which are far greater than dietary residues measured in the TDS. Several independent exposure studies suggest that the FDA dietary residues are reasonable estimates of average human exposures, whereas TMRC values are large overestimates. Using standard methodology and measured dietary residues in the TDS, the estimate of excess cancer risk from average lifetime exposure to synthetic pesticide residues in the diet appears to be less than one-in-a-million for each of the ten pesticides for which adequate data were available. Published by Elsevier Science Ireland Ltd. C1 UNIV CALIF BERKELEY, DIV BIOCHEM & MOL BIOL, BERKELEY, CA 94720 USA. CALIF ENVIRONM PROTECT AGCY, OFF ENVIRONM HLTH HAZARD ASSESSMENT, BERKELEY, CA 94704 USA. RP Gold, LS (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV LIFE SCI, BERKELEY, CA 94720 USA. NR 60 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER IRELAND LTD PI CLARE PA ELSEVIER HOUSE, BROOKVALE PLAZA, EAST PARK SHANNON, CO, CLARE, 00000, IRELAND SN 0304-3835 EI 1872-7980 J9 CANCER LETT JI Cancer Lett. PD AUG 19 PY 1997 VL 117 IS 2 BP 195 EP 207 PG 13 WC Oncology SC Oncology GA XR088 UT WOS:A1997XR08800009 ER PT J AU Liu, N Lamerdin, JE Tucker, JD Zhou, ZQ Walter, CA Albala, JS Busch, DB Thompson, LH AF Liu, N Lamerdin, JE Tucker, JD Zhou, ZQ Walter, CA Albala, JS Busch, DB Thompson, LH TI The human XRCC9 gene corrects chromosomal instability and mutagen sensitivities in CHO UV40 cells SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE DNA repair; radiation sensitivity; chromosome aberrations; sister chromatid exchange ID STRAND BREAK REPAIR; IONIZING-RADIATION SENSITIVITY; SISTER-CHROMATID EXCHANGE; PIGMENTOSUM VARIANT CELLS; CROSS-LINKING AGENTS; CHINESE-HAMSTER CELL; DNA-REPAIR; V(D)J RECOMBINATION; SACCHAROMYCES-CEREVISIAE; POSTREPLICATION REPAIR AB The Chinese hamster ovary (CHO) mutant UV40 cell line is hypersensitive to UV and ionizing radiation, simple alkylating agents, and DNA cross-linking agents. The mutant cells also have a high level of spontaneous chromosomal aberrations and 3-fold elevated sister chromatid exchange. We cloned and sequenced a human cDNA, designated XRCC9, that partially corrected the hypersensitivity of UV40 to mitomycin C, cisplatin, ethyl methanesulfonate, UV, and gamma-radiation. The spontaneous chromosomal aberrations in XRCC9 cDNA transformants wc re almost fully corrected whereas sister chromatid exchanges were unchanged. The XRCC9 genomic sequence was cloned and mapped to chromosome 9p13. The translated,YRCC9 sequence of 622 amino acids has no similarity with known proteins, The 2.5-kb, XRCC9 mRNA seen in the parental cells was undetectable in UV40 cells, The mRNA levels in testis were up to 10-fold higher compared with other human tissues and up to 100-fold higher compared with other baboon tissues, XRCC9 is a candidate tumor suppressor gene that might operate in a postreplication repair or a cell cycle checkpoint function. C1 LAWRENCE LIVERMORE NATL LAB,BBR PROGRAM,L452,LIVERMORE,CA 94551. UNIV TEXAS,HLTH SCI CTR,DEPT CELLULAR & STRUCT BIOL,SAN ANTONIO,TX 78284. ARMED FORCES INST PATHOL,DEPT ENVIRONM & TOXICOL PATHOL,WASHINGTON,DC 20306. FU NCI NIH HHS [P01 CA034936, CA34936]; NIGMS NIH HHS [GM32833, R01 GM032833] NR 60 TC 63 Z9 64 U1 0 U2 4 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD AUG 19 PY 1997 VL 94 IS 17 BP 9232 EP 9237 DI 10.1073/pnas.94.17.9232 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XR765 UT WOS:A1997XR76500059 PM 9256465 ER PT J AU Vlcek, C Paces, V Maltsev, N Paces, J Haselkorn, R Fonstein, M AF Vlcek, C Paces, V Maltsev, N Paces, J Haselkorn, R Fonstein, M TI Sequence of a 189-kb segment of the chromosome of Rhodobacter capsulatus SB1003 SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ANOXYGENIC PHOTOSYNTHETIC BACTERIA; NITROGEN-FIXATION GENES; COSMID ENCYCLOPEDIA; ESCHERICHIA-COLI; GENOME; EXPRESSION; DNA; REPRESSION; VECTORS; REGION AB Cosmids from the 1A3-1A10 region of the complete miniset were individually subcloned by using the vector M13 mp18, Sequences of each cosmid were assembled from about 400 DNA fragments generated from the ends of these phage subclones and merged into one 189-kb contig, About 160 ORFs identified by the CodonUse program were subjected to similarity searches. The biological functions of 80 ORFs could be assigned reliably by using the WIT and Magpie genome investigation tools, Eighty percent of these recognizable ORFs were organized in functional clusters, which simplified assignment decisions and increased the strength of the predictions, A set of 26 genes for cobalamin biosynthesis, genes for polyhydroxyalkanoic acid metabolism, DNA replication and recombination, and DNA gyrase were among those identified, Most of the ORFs lacking significant similarity with reference databases also were grouped, There are two large clusters of these ORFs, one located between 45 and 67 kit of the map, and the other between 150 and 183 kb, Nine of the loosely identified ORFs (of 15) of the first of these clusters match ORFs from phages or transposons. The other cluster also has four ORFs of possible phage origin. C1 UNIV CHICAGO, DEPT MOL GENET & CELL BIOL, CHICAGO, IL 60637 USA. ACAD SCI CZECH REPUBL, INST MOL GENET, CZ-16637 PRAGUE 6, CZECH REPUBLIC. ARGONNE NATL LAB, DIV MATH & COMP SCI, ARGONNE, IL 60439 USA. RI Paces, Jan/C-8851-2009; Vlcek, Cestmir/I-8820-2014 OI Paces, Jan/0000-0003-3059-6127; NR 29 TC 28 Z9 56 U1 1 U2 1 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 AUG 19 PY 1997 VL 94 IS 17 BP 9384 EP 9388 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XR765 UT WOS:A1997XR76500085 PM 9256491 ER PT J AU Yu, KM Ridgway, MC AF Yu, KM Ridgway, MC TI Direct observation of the amphoteric behavior of Ge in InP modified by P co-implantation SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRICAL CHARACTERISTICS; LATTICE LOCATION; IV ELEMENTS; DAMAGE; GAAS; ACTIVATION; CARBON; SI+; SE AB We have investigated the preferred substitution of Ge in InP by altering the focal stoichiometry of the InP substrate. By co-implanting P with Ge to create a group V-rich environment, we directly observed an enhancement of the Ge substituting the In sublattice. A corresponding increase in the n-type conductivity by as much as three times was also observed in the Ge and P co-implanted sample. However, due to the altered local stoichiometry, the Ge solubility in InP was reduced by a factor of 2. The residual crystalline damage in the P co-implanted InP after annealing was also decreased due to the compensation of the nonstoichiometry related damage by the excess P in the middle of the implanted region. (C) 1997 American Institute of Physics. C1 AUSTRALIAN NATL UNIV,DEPT ELECT MAT ENGN,CANBERRA,ACT 0200,AUSTRALIA. RP Yu, KM (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. 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 19 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 18 PY 1997 VL 71 IS 7 BP 939 EP 941 DI 10.1063/1.119695 PG 3 WC Physics, Applied SC Physics GA XR278 UT WOS:A1997XR27800027 ER PT J AU Goeckner, MJ Bennett, TK Cohen, SA AF Goeckner, MJ Bennett, TK Cohen, SA TI A source of hyperthermal neutrals for materials processing SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM; ENERGY; GENERATION; REFLECTION; SURFACES; FILM; IONS; SI AB In this letter, we describe a unique method of producing hyperthermal neutrals for material processing. The hyperthermal neutrals are produced by accelerating inns across a sheath from a plasma onto a surface, On impact, the ions are neutralized and reflected with similar to 50% of their incident energy, These neutrals then bounce off of additional surfaces prior to impacting the target, This unique multiple bounce system was developed for the following reasons: to reduce contamination from sputtered surface material, improve beam uniformity, and reduce UV radiation in the hc atn path. As a test of this method, we built a prototype beam source and used it to ash photoresist at rates up to 0.022 mu m/min. These rates are consistent with a predicted neutral beam flux, 2 x 10(14) cm(-2) s(-1). In addition, a simple model is used to indicate that this method is capable of producing economically acceptable ash rates. Comparisons with other neutral-beam production methods are made. (C) 1997 American Institute of Physics. RP Goeckner, MJ (reprint author), PRINCETON PLASMA PHYS LAB,PLASMA SCI & TECHNOL DEPT,JAMES FORRESTAL CAMPUS,PRINCETON,NJ 08543, USA. RI Goeckner, Matthew/A-8217-2009 NR 26 TC 29 Z9 29 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 18 PY 1997 VL 71 IS 7 BP 980 EP 982 DI 10.1063/1.119706 PG 3 WC Physics, Applied SC Physics GA XR278 UT WOS:A1997XR27800041 ER PT J AU Kopidakis, G Wang, CZ Soukoulis, CM Ho, KM AF Kopidakis, G Wang, CZ Soukoulis, CM Ho, KM TI A tight-binding molecular dynamics study of phonon anharmonic effects in diamond and graphite SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID AMORPHOUS-CARBON; ELECTRONIC-PROPERTIES; SILICON; SCATTERING; SURFACES AB We study the temperature dependence of phonon frequency shifts and phonon linewidths in diamond and graphite using tight-binding molecular dynamics simulations. The calculation of one-phonon spectral intensities of several modes through velocity-velocity correlation functions allows a quantitative and nonperturbative study of these anharmonic effects. Our results for the zone-centre optical mode of diamond, for which experimental data are available, agree very well with first-order Raman-scattering measurements. C1 IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. RP Kopidakis, G (reprint author), IOWA STATE UNIV,AMES LAB,AMES,IA 50011, USA. RI Soukoulis, Costas/A-5295-2008 NR 27 TC 7 Z9 7 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD AUG 18 PY 1997 VL 9 IS 33 BP 7071 EP 7080 DI 10.1088/0953-8984/9/33/009 PG 10 WC Physics, Condensed Matter SC Physics GA XR708 UT WOS:A1997XR70800009 ER PT J AU Eberling, JL Bankiewicz, KS Jordan, S VanBrocklin, HF Jagust, WJ AF Eberling, JL Bankiewicz, KS Jordan, S VanBrocklin, HF Jagust, WJ TI PET studies of functional compensation in a primate model of Parkinson's disease SO NEUROREPORT LA English DT Article DE dopamine; FMT; MPTP; nigrostriata; Parkinson's disease; PET; putamen; substantia nigra ID MPTP-INDUCED PARKINSONISM; 1-METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE MPTP; SUBSTANTIA-NIGRA; MONKEYS; DOPAMINE; NEURONS; NEUROTOXICITY; BRAIN; N-METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE; HEMIPARKINSONISM AB MPTP 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine is a neurotoxin that produces degeneration of nigrostriatal dopaminergic neurons and a chronic parkinsonian condition in primates. Positron emission tomography (PET) studies of rhesus macaques at various time points following unilateral MPTP administration demonstrated a different time course of degeneration in the dopaminergic terminals in the putamen and in the cell bodies in the substantia nigra, consistent with other evidence of retrograde degeneration. In addition, the substantia nigra showed a transient upregulation in dopaminergic function in the lesioned hemisphere indicating functional compensation. This plasticity has important implications for the therapeutic effects of growth factors and other. potential treatments for neurodegenerative diseases. C1 SOMATIX THERAPY CORP,ALAMEDA,CA. MARTINEZ VA MED CTR,DEPT NEUROL,DAVIS,CA. MARTINEZ VA MED CTR,DEPT NEUROL,DAVIS,CA. UNIV CALIF DAVIS,DAVIS,CA. RP Eberling, JL (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR FUNCT IMAGING,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 25 TC 32 Z9 32 U1 0 U2 0 PU RAPID SCIENCE PUBLISHERS PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8NH SN 0959-4965 J9 NEUROREPORT JI Neuroreport PD AUG 18 PY 1997 VL 8 IS 12 BP 2727 EP 2733 DI 10.1097/00001756-199708180-00017 PG 7 WC Neurosciences SC Neurosciences & Neurology GA XU424 UT WOS:A1997XU42400017 PM 9295108 ER PT J AU Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Barberis, E Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Drinkard, J Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Goussiou, A Graf, N Grannis, PD Green, DR Green, J Grenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LIDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rapidis, PA Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Barberis, E Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Drinkard, J Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Goussiou, A Graf, N Grannis, PD Green, DR Green, J Grenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LIDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rapidis, PA Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Direct measurement of the top quark mass SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTOR AB We measure the top quark mass m(t) using pairs produced in the DO detector by root s = 1.8 TeV collisions in a 125 pb(-1) exposure at the Fermilab Tevatron. We make a two constraint fit to m(t) in --> bW(+)<(b)over bar W-> final states with one W decaying to and the other to e nu or mu nu. Events are binned in fit mass versus a measure of probability for events to be signal rather than background. Likelihood fits to the data yield m(t) = 173.3 +/- 5.6(stat) +/- 6.2(syst) GeV/c(2). C1 UNIV ARIZONA, TUCSON, AZ 85721 USA. BOSTON UNIV, BOSTON, MA 02215 USA. BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. BROWN UNIV, PROVIDENCE, RI 02912 USA. UNIV BUENOS AIRES, BUENOS AIRES, DF, ARGENTINA. UNIV CALIF DAVIS, DAVIS, CA 95616 USA. UNIV CALIF IRVINE, IRVINE, CA 92697 USA. UNIV CALIF RIVERSIDE, RIVERSIDE, CA 92521 USA. CTR BRASILEIRO PESQUISAS FIS, LAFEX, RIO DE JANEIRO, BRAZIL. CINVESTAV, MEXICO CITY 14000, DF, MEXICO. COLUMBIA UNIV, NEW YORK, NY 10027 USA. UNIV DELHI, DELHI 110007, INDIA. FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. FLORIDA STATE UNIV, TALLAHASSEE, FL 32306 USA. UNIV HAWAII, HONOLULU, HI 96822 USA. UNIV ILLINOIS, CHICAGO, IL 60607 USA. INDIANA UNIV, BLOOMINGTON, IN 47405 USA. IOWA STATE UNIV SCI & TECHNOL, AMES, IA 50011 USA. KOREA UNIV, SEOUL 136701, SOUTH KOREA. KYUNGSUNG UNIV, PUSAN 608736, SOUTH KOREA. LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV MARYLAND, COLLEGE PK, MD 20742 USA. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. MICHIGAN STATE UNIV, E LANSING, MI 48824 USA. UNIV NEBRASKA, LINCOLN, NE 68588 USA. NYU, NEW YORK, NY 10003 USA. NORTHEASTERN UNIV, BOSTON, MA 02115 USA. NO ILLINOIS UNIV, DE KALB, IL 60115 USA. NORTHWESTERN UNIV, EVANSTON, IL 60208 USA. UNIV NOTRE DAME, NOTRE DAME, IN 46556 USA. UNIV OKLAHOMA, NORMAN, OK 73019 USA. PUNJABI UNIV, CHANDIGARH 160014, INDIA. MOSCOW HIGH ENERGY PHYS INST, PROTVINO 142284, RUSSIA. PURDUE UNIV, W LAFAYETTE, IN 47907 USA. RICE UNIV, HOUSTON, TX 77005 USA. UNIV FED RIO DE JANEIRO, RIO DE JANEIRO, BRAZIL. UNIV ROCHESTER, ROCHESTER, NY 14267 USA. CE SACLAY, CEA, DAPNIA, SERV PHYS PARTICULES, GIF SUR YVETTE, FRANCE. SEOUL NATL UNIV, SEOUL, SOUTH KOREA. SUNY STONY BROOK, STONY BROOK, NY 11794 USA. TATA INST FUNDAMENTAL RES, BOMBAY 400005, MAHARASHTRA, INDIA. UNIV TEXAS, ARLINGTON, TX 76019 USA. TEXAS A&M UNIV, COLLEGE STN, TX 77843 USA. RP UNIV LOS ANDES, SANTA FE DE BOGOTA, COLOMBIA. RI Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Roe, Natalie/A-8798-2012; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Klyukhin, Vyacheslav/D-6850-2012; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016; OI Belyaev, Alexander/0000-0002-1733-4408; Aihara, Hiroaki/0000-0002-1907-5964; Dudko, Lev/0000-0002-4462-3192; Klyukhin, Vyacheslav/0000-0002-8577-6531; De, Kaushik/0000-0002-5647-4489; Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108; Baarmand, Marc/0000-0002-9792-8619 NR 17 TC 108 Z9 108 U1 0 U2 6 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 AUG 18 PY 1997 VL 79 IS 7 BP 1197 EP 1202 DI 10.1103/PhysRevLett.79.1197 PG 6 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700007 ER PT J AU Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cumings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Drinkard, J Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Goussiou, A Graf, N Grannis, PD Green, DR Green, J Greenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnokov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Keohoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Leuking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amidi, E Amos, N Anderson, EW Astur, R Baarmand, MM Baden, A Balamurali, V Balderston, J Baldin, B Banerjee, S Bantly, J Bartlett, JF Bazizi, K Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cumings, MAC Cutts, D Dahl, OI Davis, K De, K DelSignore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Draper, P Drinkard, J Ducros, Y Dudko, LV Dugad, SR Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glenn, S Gobbi, B Goforth, M Goldschmidt, A Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Goussiou, A Graf, N Grannis, PD Green, DR Green, J Greenlee, H Grim, G Grinstein, S Grossman, N Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, P Gutnokov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Huehn, T Ito, AS James, E Jaques, J Jerger, SA Jesik, R Jiang, JZY JoffeMinor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Keohoe, R Kelly, ML Kim, CL Kim, SK Klatchko, A Klima, B Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kourlas, J Kozelov, AV Kozlovski, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Lan, H Lander, R Landry, F Landsberg, G Lauer, B Leflat, A Li, H Li, J LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, Q Liu, YC Lobkowicz, F Loken, SC Lokos, S Leuking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R MaganaMendoza, L Mani, S Mao, HS Markeloff, R Markosky, L Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rasmussen, L Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J SanchezHernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shupe, M Singh, H Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sood, PM Sosebee, M Sotnikova, N Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yepes, P Yoshikawa, C Youssef, S Yu, J Yu, Y Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Measurement of the top quark pair production cross section in p(p)over-bar collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTOR AB We present a measurement of the production cross section in collisions at root s = 1.8 TeV by the DO experiment at the Fermilab Tevatron. The measurement is based on data from an integrated luminosity of approximately 125 pb(-1) accumulated during the 1992-1996 collider run. We observe 39 candidate events in the dilepton and lepton + jets decay channels with an expected background of 13.7 +/- 2.2 events. For a top quark mass of 173.3 GeV/c(2), we measure the production cross section to be 5.5 +/- 1.8 pb. C1 UNIV ARIZONA,TUCSON,AZ 85721. BOSTON UNIV,BOSTON,MA 02215. BROOKHAVEN NATL LAB,UPTON,NY 11973. BROWN UNIV,PROVIDENCE,RI 02912. UNIV BUENOS AIRES,BUENOS AIRES,DF,ARGENTINA. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF IRVINE,IRVINE,CA 92697. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. CINVESTAV,MEXICO CITY 14000,DF,MEXICO. COLUMBIA UNIV,NEW YORK,NY 10027. UNIV DELHI,DELHI 110007,INDIA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV HAWAII,HONOLULU,HI 96822. UNIV ILLINOIS,CHICAGO,IL 60607. INDIANA UNIV,BLOOMINGTON,IN 47405. IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. KOREA UNIV,SEOUL 136701,SOUTH KOREA. KYUNGSUNG UNIV,PUSAN,SOUTH KOREA. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. MOSCOW MV LOMONOSOV STATE UNIV,MOSCOW,RUSSIA. UNIV NEBRASKA,LINCOLN,NE 68588. NYU,NEW YORK,NY 10003. NORTHEASTERN UNIV,BOSTON,MA 02115. NO ILLINOIS UNIV,DE KALB,IL 60115. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. UNIV OKLAHOMA,NORMAN,OK 73019. PANJAB UNIV,CHANDIGARH 160014,INDIA. MOSCOW HIGH ENERGY PHYS INST,PROTVINO 142284,RUSSIA. PURDUE UNIV,W LAFAYETTE,IN 47907. RICE UNIV,HOUSTON,TX 77005. UNIV FED RIO DE JANEIRO,BR-21941 RIO JANEIRO,BRAZIL. UNIV ROCHESTER,ROCHESTER,NY 14627. CENS,CEA,DAPNIA,SERV PHYS PARTICULES,GIF SUR YVETTE,FRANCE. SEOUL NATL UNIV,SEOUL,SOUTH KOREA. SUNY STONY BROOK,STONY BROOK,NY 11794. UNIV TEXAS,ARLINGTON,TX 76019. TEXAS A&M UNIV,COLLEGE STN,TX 77843. TATA INST FUNDAMENTAL RES,COLABA 400005,MUMBAI,INDIA. RP Abachi, S (reprint author), UNIV LOS ANDES,BOGOTA,COLOMBIA. RI Belyaev, Alexander/F-6637-2015; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Roe, Natalie/A-8798-2012; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Klyukhin, Vyacheslav/D-6850-2012; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016 OI Belyaev, Alexander/0000-0002-1733-4408; Aihara, Hiroaki/0000-0002-1907-5964; Dudko, Lev/0000-0002-4462-3192; Klyukhin, Vyacheslav/0000-0002-8577-6531; De, Kaushik/0000-0002-5647-4489; Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108 NR 18 TC 84 Z9 84 U1 0 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 AUG 18 PY 1997 VL 79 IS 7 BP 1203 EP 1208 DI 10.1103/PhysRevLett.79.1203 PG 6 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700008 ER PT J AU Seligman, WG Arroyo, CG deBarbaro, L deBarbaro, P Bazarko, AO Bernstein, RH Bodek, A Bolton, T Budd, H Conrad, J Harris, DA Johnson, RA Kim, JH King, BJ Kinnel, T Lamm, MJ Lefmann, WC Marsh, W McFarland, KS McNulty, C Mishra, SR Naples, D Quintas, PZ Romosan, A Sakumoto, WK Schellman, H Sciulli, FJ Shaevitz, MH Smith, WH Spentzouris, P Stern, EG Vakili, M Yang, UK Yu, J AF Seligman, WG Arroyo, CG deBarbaro, L deBarbaro, P Bazarko, AO Bernstein, RH Bodek, A Bolton, T Budd, H Conrad, J Harris, DA Johnson, RA Kim, JH King, BJ Kinnel, T Lamm, MJ Lefmann, WC Marsh, W McFarland, KS McNulty, C Mishra, SR Naples, D Quintas, PZ Romosan, A Sakumoto, WK Schellman, H Sciulli, FJ Shaevitz, MH Smith, WH Spentzouris, P Stern, EG Vakili, M Yang, UK Yu, J TI Improved determination of alpha(s) from neutrino-nucleon scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID INELASTIC ELECTRON-SCATTERING; MUON SCATTERING; CROSS-SECTIONS; A-DEPENDENCE; FREEDOM; ENERGY; QUARKS; QCD AB We present an improved determination of the proton structure functions F-2 and xF(3) from the Columbia-Chicago-Fermilab-Rochester Collaboration nu-Fe deep inelastic scattering experiment. Comparisons to corrected high-statistics charged-lepton scattering results for F-2 from the NMC, E665, SLAG, and BCDMS experiments indicate good agreement for x > 0.1 but some discrepancy at lower x. The Q(2) evolution of both the F-2 and xF(3) structure functions yields a value of the strong coupling constant at the scale of mass of the Z boson of alpha(s)(M-Z(2)) = 0.119 +/- 0.002(expt) +/- 0.004(theory). This is one of the most precise measurements of this quantity. C1 COLUMBIA UNIV,NEW YORK,NY 10027. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. KANSAS STATE UNIV,MANHATTAN,KS 66506. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV ROCHESTER,ROCHESTER,NY 14627. UNIV WISCONSIN,MADISON,WI 53706. RP Seligman, WG (reprint author), UNIV CINCINNATI,CINCINNATI,OH 45221, USA. NR 34 TC 221 Z9 221 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 AUG 18 PY 1997 VL 79 IS 7 BP 1213 EP 1216 DI 10.1103/PhysRevLett.79.1213 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700010 ER PT J AU BarShalom, S Eilam, G Soni, A Wudka, J AF BarShalom, S Eilam, G Soni, A Wudka, J TI Probing the flavor-changing tc vertex via tree-level processes: e(+)e(-)->t(c)over-bar-v(e)(v)over-bar-(e), t(c)over-bar-e(+)e(-), and t->cW(+)W(-) SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-ENERGY COLLISIONS; VECTOR-BOSON FUSION; NEUTRAL CURRENTS; DECAYS; APPROXIMATION AB The reaction e(+)e(-) --> (e)<(nu)over bar>(e), t(c) over bare$(+)e(-) are very sensitive probes of the flavor-changing-scalar couplings which can occur in a model with one extra Higgs doublet. At the Next Linear Collider, several hundreds and up to thousands of such events may be produced if the mass of the light neutral Higgs is a few hundred GeV. We also briefly comment on the decays t --> cW(+)W(-), t --> cZZ. All of these reactions are severely suppressed in the standard model. C1 TECHNION ISRAEL INST TECHNOL,DEPT PHYS,IL-32000 HAIFA,ISRAEL. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP BarShalom, S (reprint author), UNIV CALIF RIVERSIDE,DEPT PHYS,RIVERSIDE,CA 92521, USA. NR 21 TC 46 Z9 46 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 AUG 18 PY 1997 VL 79 IS 7 BP 1217 EP 1220 DI 10.1103/PhysRevLett.79.1217 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700011 ER PT J AU Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A ValantSpaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M Lee, SJ ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML 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 Frasconi, F Gao, M 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 Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S AF Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A ValantSpaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M Lee, SJ ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML 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 Frasconi, F Gao, M 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 Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S TI Search for neutrinoless tau decays involving pi(0) or eta mesons SO PHYSICAL REVIEW LETTERS LA English DT Article ID MONTE-CARLO; LIBRARY AB We have searched for lepton flavor violating decays of the tau lepton using final states with an electron Or a muon and one or two pi(0) or eta mesons but no neutrinos. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.68 fb(-1). No evidence for signals was found, resulting in much improved limits on the branching fractions for the one-meson modes and the first upper limits for the two-meson modes. C1 CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,SAN DIEGO,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,URBANA,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. RP Bonvicini, G (reprint author), WAYNE STATE UNIV,DETROIT,MI 48202, USA. RI Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016; OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587; Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900 NR 13 TC 21 Z9 22 U1 2 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 AUG 18 PY 1997 VL 79 IS 7 BP 1221 EP 1224 DI 10.1103/PhysRevLett.79.1221 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700012 ER PT J AU Balitsky, I Ji, XD AF Balitsky, I Ji, XD TI How much of the nucleon spin is carried by glue? SO PHYSICAL REVIEW LETTERS LA English DT Article ID QCD SUM-RULES; DEEP INELASTIC-SCATTERING; RESONANCE PHYSICS; 2ND MOMENTS; PROTON; QUARK AB We estimate in the QCD sum rule approach the amount of the nucleon spin carried by the gluon angular momentum: the sum of the gluon spin and orbital angular momenta. The result indicates that gluons contribute at least one half of the nucleon spin at the scale of I GeV2. C1 JEFFERSON LAB,NEWPORT NEWS,VA 23606. UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP Balitsky, I (reprint author), OLD DOMINION UNIV,DEPT PHYS,NORFOLK,VA 23529, USA. NR 23 TC 33 Z9 33 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 AUG 18 PY 1997 VL 79 IS 7 BP 1225 EP 1228 DI 10.1103/PhysRevLett.79.1225 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700013 ER PT J AU Porter, RJ Beedoe, S Bossingham, R Bougteb, M Christie, WB Carroll, J Gong, WG Hallman, T Heilbronn, L Huang, HZ Igo, G Kirk, P Krebs, G LetessierSelvon, A Madansky, L Manso, F Matis, HS Miller, J Naudet, C Prunet, M Roche, G Schroeder, LS Seidl, P Wang, ZF Welsh, RC Wilson, WK Yegneswaran, A AF Porter, RJ Beedoe, S Bossingham, R Bougteb, M Christie, WB Carroll, J Gong, WG Hallman, T Heilbronn, L Huang, HZ Igo, G Kirk, P Krebs, G LetessierSelvon, A Madansky, L Manso, F Matis, HS Miller, J Naudet, C Prunet, M Roche, G Schroeder, LS Seidl, P Wang, ZF Welsh, RC Wilson, WK Yegneswaran, A TI Dielectron cross section measurements in nucleus-nucleus reactions at 1.0A GeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-ION COLLISIONS; TRANSVERSE-MOMENTUM DEPENDENCE; P-BE COLLISIONS; DILEPTON PRODUCTION; P+P COLLISIONS; MASS; MATTER; PION; YIELDS; MESONS AB We present measured dielectron production cross sections for Ca + Ca, C + C, He + Ca, and d + Ca reactions at 1.0 AGeV. Statistical uncertainties and systematic effects are smaller than in previous dilepton spectrometer (DLS) nucleus-nucleus data. For pair mass M less than or equal to 0.35 GeV/c(2) we obtain (1) the Ca + Ca cross section is larger than the previous DLS measurement and current model results, (2) the mass spectra suggest large contributions from pi(0) and eta Dalitz decays, and (3) d sigma/dM proportional to A(p)A(T). For M > 0.5 GeV/c(2) the Ca + Ca to C + C cross section ratio is significantly larger than the ratio of A(p)A(T) values. C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90095. UNIV CLERMONT FERRAND,IN2P3,F-63177 AUBIERE,FRANCE. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. LOUISIANA STATE UNIV,BATON ROUGE,LA 70803. WAYNE STATE UNIV,DETROIT,MI 48201. RP Porter, RJ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Heilbronn, Lawrence/J-6998-2013 OI Heilbronn, Lawrence/0000-0002-8226-1057 NR 29 TC 161 Z9 165 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 AUG 18 PY 1997 VL 79 IS 7 BP 1229 EP 1232 DI 10.1103/PhysRevLett.79.1229 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700014 ER PT J AU Svensson, CE Baktash, C Cameron, JA Devlin, M Eberth, J Flibotte, S Haslip, DS LaFosse, DR Lee, IY Macchiavelli, AO MacLeod, RW Nieminen, JM Paul, SD Riedinger, LL Rudolph, D Sarantites, DG Thomas, HG Waddington, JC Weintraub, W Wilson, JN Afanasjev, AV Ragnarsson, I AF Svensson, CE Baktash, C Cameron, JA Devlin, M Eberth, J Flibotte, S Haslip, DS LaFosse, DR Lee, IY Macchiavelli, AO MacLeod, RW Nieminen, JM Paul, SD Riedinger, LL Rudolph, D Sarantites, DG Thomas, HG Waddington, JC Weintraub, W Wilson, JN Afanasjev, AV Ragnarsson, I TI Observation and quadrupole-moment measurement of the first superdeformed band in the A similar to 60 mass region SO PHYSICAL REVIEW LETTERS LA English DT Article ID ROTATIONAL BANDS; STATES AB A high-spin rotational cascade of six gamma rays has been observed in Zn-62. The quadrupole moment of 2.7(-0.5)(+0.7) e b measured for this band corresponds to a deformation beta(2) = 0.45(-0.07)(+0.10). The properties of this band are in excellent agreement with calculations that predict high-spin superdeformed bands in Zn-62 with deformations beta(2) = 0.41-0.49. These results establish a new region of superdeformation for nuclei with neutron and proton numbers N, Z approximate to 30-32. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. WASHINGTON UNIV,DEPT CHEM,ST LOUIS,MO 63130. UNIV COLOGNE,INST KERNPHYS,D-50937 COLOGNE,GERMANY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. UNIV MUNICH,SEKT PHYS,D-85748 GARCHING,GERMANY. LUND INST TECHNOL,DEPT MATH PHYS,S-22100 LUND,SWEDEN. RP Svensson, CE (reprint author), MCMASTER UNIV,DEPT PHYS & ASTRON,HAMILTON,ON L8S 4M1,CANADA. RI Rudolph, Dirk/D-4259-2009; Devlin, Matthew/B-5089-2013 OI Rudolph, Dirk/0000-0003-1199-3055; Devlin, Matthew/0000-0002-6948-2154 NR 25 TC 92 Z9 92 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 AUG 18 PY 1997 VL 79 IS 7 BP 1233 EP 1236 DI 10.1103/PhysRevLett.79.1233 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700015 ER PT J AU Diehl, S Cubaynes, D Wuilleumier, FJ Bizau, JM Journel, L Kennedy, ET Blancard, C VoKy, L Faucher, P Hibbert, A Berrah, N Morgan, TJ Bozek, J Schlachter, AS AF Diehl, S Cubaynes, D Wuilleumier, FJ Bizau, JM Journel, L Kennedy, ET Blancard, C VoKy, L Faucher, P Hibbert, A Berrah, N Morgan, TJ Bozek, J Schlachter, AS TI Experimental observation and theoretical calculations of Rydberg series in hollow lithium atomic states SO PHYSICAL REVIEW LETTERS LA English DT Article AB Several extended Rydberg series have been experimentally identified in triply excited states of hollow lithium, by use of electron spectrometry and synchrotron radiation at the Advanced Light Source. Energies, partial cross sections, and quantum defects have also been calculated using the R-matrix approximation. Our results show that the two inner electrons stay in a core-excited state of given symmetry while the behavior of the third electron is mostly governed by the nuclear potential screened by the two inner electrons. C1 DUBLIN CITY UNIV,SCH PHYS SCI,DUBLIN 9,IRELAND. CTR ETUD LIMEIL VALENTON,DRIF,F-94195 VILLENEUVE ST GEO,FRANCE. OBSERV COTE AZUR,F-06304 NICE,FRANCE. QUEENS UNIV BELFAST,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. WESTERN MICHIGAN UNIV,KALAMAZOO,MI 49008. WESLEYAN UNIV,MIDDLETOWN,CT 06459. UNIV CALIF DAVIS,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Diehl, S (reprint author), UNIV PARIS 11,LAB SPECT ATOM & ION,BATIMENT 350,F-91405 ORSAY,FRANCE. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 12 TC 39 Z9 40 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 AUG 18 PY 1997 VL 79 IS 7 BP 1241 EP 1244 DI 10.1103/PhysRevLett.79.1241 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700017 ER PT J AU Chen, SY Sreenivasan, KR Nelkin, M AF Chen, SY Sreenivasan, KR Nelkin, M TI Inertial range scalings of dissipation and enstrophy in isotropic turbulence SO PHYSICAL REVIEW LETTERS LA English DT Article ID FULLY-DEVELOPED TURBULENCE; SMALL-SCALE STRUCTURES; 3-DIMENSIONAL TURBULENCE; HOMOGENEOUS TURBULENCE; VORTEX; INTERMITTENCY; INSTABILITY; VORTICITY AB The inertial range scalings of local averages of energy dissipation rate and enstrophy (vorticity squared) are studied using high resolution direct numerical simulation data for homogeneous and isotropic turbulence. The Taylor microscale Reynolds number is 216. It is found that the enstrophy is more intermittent than dissipation, consistent with previous one-dimensional surrogate measurements at high Reynolds numbers. Contrary to some recent expectations, enstrophy and dissipation have different exponents. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. YALE UNIV,MASON LAB,NEW HAVEN,CT 06520. NYU,DEPT PHYS,NEW YORK,NY 10003. CUNY CITY COLL,LEVICH INST,NEW YORK,NY 10031. RP Chen, SY (reprint author), IBM CORP,DIV RES,THOMAS J WATSON RES CTR,POB 218,YORKTOWN HTS,NY 10598, USA. RI Chen, Shiyi/A-3234-2010 NR 32 TC 50 Z9 51 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 AUG 18 PY 1997 VL 79 IS 7 BP 1253 EP 1256 DI 10.1103/PhysRevLett.79.1253 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700020 ER PT J AU Glenzer, SH Back, CA Suter, LJ Blain, MA Landen, OL Lindl, JD MacGowan, BJ Stone, GF Turner, RE Wilde, BH AF Glenzer, SH Back, CA Suter, LJ Blain, MA Landen, OL Lindl, JD MacGowan, BJ Stone, GF Turner, RE Wilde, BH TI Thomson scattering from inertial-confinement-fusion Hohlraum plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID LASER-PRODUCED PLASMAS; TEMPERATURES; TRANSPORT; IGNITION; FACILITY; LIGHT AB We present the first Thomson scattering measurements of local plasma conditions in ignition-relevant, gas-filled, inertial-confinement-fusion hohlraums. The experimental data provide a benchmark for two-dimensional hydrodynamic simulations using LASNEX, which is presently in use to predict the performance of future megajoule laser-driven hohlraums of the National Ignition Facility. The data are consistent with modeling using significantly inhibited heat transport at the peak of the drive. Further, we find that stagnating plasma regions on the hohlraum axis are well described by the calculations. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. CTR ETUD LIMEIL VALENTON, F-94195 VILLENEUVE ST GEO, FRANCE. RP LAWRENCE LIVERMORE NATL LAB, POB 808,L-399, LIVERMORE, CA 94551 USA. NR 31 TC 53 Z9 53 U1 0 U2 5 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 AUG 18 PY 1997 VL 79 IS 7 BP 1277 EP 1280 DI 10.1103/PhysRevLett.79.1277 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700026 ER PT J AU Baltes, H Yacoby, Y Pindak, R Clarke, R Pfeiffer, L Berman, L AF Baltes, H Yacoby, Y Pindak, R Clarke, R Pfeiffer, L Berman, L TI Measurement of the x-ray diffraction phase in a 2D crystal SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-MICROSCOPY; INTERFERENCE METHOD; MACROMOLECULES; LAYERS AB We report the determination of the x-ray diffraction phase in 2D crystals, systems which are periodic in two dimensions and aperiodic in the third. The method consists of measuring the intensity of pairs of parallel, coherent diffracted beams, generated by an incident beam and a beam reflected from a gold mirror layer evaporated on the 2D crystal. Our experiments on an epitaxial GaAs/AlAs heterostructure with aperiodic layering demonstrate that it is possible to measure the phase. This opens the way for direct structural studies of a wide variety of 2D crystals. C1 HEBREW UNIV JERUSALEM,RACAH INST PHYS,IL-91904 JERUSALEM,ISRAEL. UNIV MICHIGAN,RANDALL LAB PHYS,ANN ARBOR,MI 48109. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11964. RP Baltes, H (reprint author), AT&T BELL LABS,LUCENT TECHNOL,700 MT AVE,MURRAY HILL,NJ 07974, USA. NR 21 TC 11 Z9 11 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 AUG 18 PY 1997 VL 79 IS 7 BP 1285 EP 1288 DI 10.1103/PhysRevLett.79.1285 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700028 ER PT J AU Cleri, F Yip, S Wolf, D Phillpot, SR AF Cleri, F Yip, S Wolf, D Phillpot, SR TI Atomic-scale mechanism of crack-tip plasticity: Dislocation nucleation and crack-tip shielding SO PHYSICAL REVIEW LETTERS LA English DT Article ID FRACTURE-BEHAVIOR; DUCTILE; BRITTLE; SIMULATION; EMISSION; CRYSTALS; DYNAMICS AB By isolating the process of dislocation emission from a crack tip under an applied tensile stress, we extract from a molecular dynamics simulation the atomic-level displacement and stress fields on the activated slip plane before and after the nucleation event. The stress-displacement relations so obtained provide a direct link with recent continuum descriptions of brittle versus ductile behavior in crack propagation. Crack-tip shielding by the emitted dislocations is demonstrated, as is the role of surface steps in dislocation nucleation and crack-tip blunting. C1 ENEA, CTR RIC CASACCIA, DIV MAT AVANZATI, I-00100 ROME, AD, ITALY. MIT, DEPT NUCL ENGN, CAMBRIDGE, MA 02139 USA. RP ARGONNE NATL LAB, DIV MAT SCI, 9700 S CASS AVE, ARGONNE, IL 60439 USA. RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 23 TC 80 Z9 82 U1 3 U2 17 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 AUG 18 PY 1997 VL 79 IS 7 BP 1309 EP 1312 DI 10.1103/PhysRevLett.79.1309 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700034 ER PT J AU Simak, SI Haussermann, U Abrikosov, IA Eriksson, O Wills, JM Lidin, S Johansson, B AF Simak, SI Haussermann, U Abrikosov, IA Eriksson, O Wills, JM Lidin, S Johansson, B TI Stability of the anomalous large-void CoSn structure SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON LOCALIZATION; BRILLOUIN-ZONE; SPECIAL POINTS; SYSTEMS; BAND AB The crystal structure of CoSn represents a highly peculiar intermetallic structure type because of the presence of a large void and highly nonspherically coordinated tin atoms. Voids in crystal structures of intermetallic compounds are most unusual and always give rise to speculations whether the observed phase is the ground state or not. Here we examine this problem by means of ab initio calculations and show that the void structure of CoSn is indeed the stable phase. With pressure we predict the following sequence of structural transformations: CoSn type --> FeSi type --> CsCl type. The structural properties of CoSn are understood in terms of competition between covalent and metallic bonding in the system. C1 LUND UNIV,DEPT INORGAN CHEM 2,S-22100 LUND,SWEDEN. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87544. RP Simak, SI (reprint author), UNIV UPPSALA,DEPT PHYS,CONDENSED MATTER THEORY GRP,S-75121 UPPSALA,SWEDEN. RI Eriksson, Olle/E-3265-2014; Simak, Sergei/C-3030-2014; OI Eriksson, Olle/0000-0001-5111-1374; Simak, Sergei/0000-0002-1320-389X; Lidin, Sven/0000-0001-9057-8233 NR 24 TC 32 Z9 32 U1 1 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 AUG 18 PY 1997 VL 79 IS 7 BP 1333 EP 1336 DI 10.1103/PhysRevLett.79.1333 PG 4 WC Physics, Multidisciplinary SC Physics GA XR287 UT WOS:A1997XR28700040 ER PT J AU Raghavan, S Kenkre, VM Bishop, AR AF Raghavan, S Kenkre, VM Bishop, AR TI Phase-nonlinearity interplay in small quantum systems SO PHYSICS LETTERS A LA English DT Article ID SCHRODINGER-EQUATION; DIMER; LATTICE AB We report effects of the interplay of quantum phases and nonlinearity in small quantum systems that are characterized by strong interactions between a quasiparticle (an excitation or an electron) and lattice vibrations, and are described by the discrete nonlinear Schrodinger equation. The issue under investigation is the influence that features of the initial placement of a quasiparticle can have on the process of self-trapping. We find that initial phases profoundly control the dependence of self-trapping on initial inhomogeneity. We also find that the only non-trivial stationary state of the system disappears in the presence of complex initial site amplitudes and that the amplitude of oscillations, which dips sharply to zero at the stationary state for real initial amplitudes, approaches a nonzero minimum for complex initial amplitudes. (C) 1997 Published by Elsevier Science B.V. C1 UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Raghavan, S (reprint author), UNIV NEW MEXICO,CTR ADV STUDIES,ALBUQUERQUE,NM 87131, USA. NR 22 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD AUG 18 PY 1997 VL 233 IS 1-2 BP 73 EP 78 DI 10.1016/S0375-9601(97)00451-9 PG 6 WC Physics, Multidisciplinary SC Physics GA XT130 UT WOS:A1997XT13000013 ER PT J AU Grossman, T Wool, A AF Grossman, T Wool, A TI Computational experience with approximation algorithms for the set covering problem SO EUROPEAN JOURNAL OF OPERATIONAL RESEARCH LA English DT Article DE set covering; optimization; neural networks; approximation algorithms ID OPTIMIZATION AB The Set Covering problem (SCP) is a well known combinatorial optimization problem, which is NP-hard. We conducted a comparative study of nine different approximation algorithms for the SCP, including several greedy variants, fractional relaxations, randomized algorithms and a neural network algorithm. The algorithms were tested on a set of random-generated problems with up to 500 rows and 5000 columns, and on two sets of problems originating in combinatorial questions with up to 28160 rows and 11264 columns. On the random problems and on one set of combinatorial problems, the best algorithm among those we tested was a randomized greedy algorithm, with the neural network algorithm very close in second place. On the other set of combinatorial problems, the best algorithm was a deterministic greedy variant, and the randomized algorithms (both randomized greedy and neural network) performed quite poorly. The other algorithms we tested were always inferior to the ones mentioned above. (C) 1997 Elsevier Science B.V. C1 LOS ALAMOS NATL LAB,CNLS,LOS ALAMOS,NM 87545. WEIZMANN INST SCI,DEPT APPL MATH & COMP SCI,IL-76100 REHOVOT,ISRAEL. RP Grossman, T (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Wool, Avishai/K-6185-2013 OI Wool, Avishai/0000-0002-8371-4759 NR 30 TC 58 Z9 62 U1 8 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-2217 J9 EUR J OPER RES JI Eur. J. Oper. Res. PD AUG 16 PY 1997 VL 101 IS 1 BP 81 EP 92 DI 10.1016/S0377-2217(96)00161-0 PG 12 WC Management; Operations Research & Management Science SC Business & Economics; Operations Research & Management Science GA YB873 UT WOS:A1997YB87300008 ER PT J AU Loehle, C AF Loehle, C TI Untainted by money SO NEW SCIENTIST LA English DT Editorial Material RP Loehle, C (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 SN 0262-4079 J9 NEW SCI JI New Sci. PD AUG 16 PY 1997 VL 155 IS 2095 BP 44 EP 44 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XR935 UT WOS:A1997XR93500033 PM 11656796 ER PT J AU Tang, Q Harrata, AK Lee, CS AF Tang, Q Harrata, AK Lee, CS TI Two-dimensional analysis of recombinant E-coli proteins using capillary isoelectric focusing electrospray ionization mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID PERFORMANCE AB On-line combination of capillary isoelectric focusing with electrospray ionization mass spectrometry is applied for a two-dimensional analysis of Escherichia coli proteins. The proteins are focused and cathodically mobilized in a polyacrylamide coated capillary. At the end of the capillary, various protein zones are analyzed by mass spectrometry coupled through an electrospray interface, Comparisons with silver-stained two-dimensional gel electrophoresis are made with regard to mass determination, resolution, speed, and sensitivity, Direct identification of a recombinant fusion protein of glutathione S-transferase and striped bass growth hormone is achieved without any prior protein isolation procedures. C1 US DOE,DEPT CHEM,AMES,IA 50011. US DOE,AMES LAB,AMES,IA 50011. NR 21 TC 67 Z9 72 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD AUG 15 PY 1997 VL 69 IS 16 BP 3177 EP 3182 DI 10.1021/ac970015o PG 6 WC Chemistry, Analytical SC Chemistry GA XQ972 UT WOS:A1997XQ97200007 ER PT J AU Jacobson, SC Ramsey, JM AF Jacobson, SC Ramsey, JM TI Electrokinetic focusing in microfabricated channel structures SO ANALYTICAL CHEMISTRY LA English DT Article ID PLANAR CHIPS TECHNOLOGY; CAPILLARY ELECTROPHORESIS; CHEMICAL-ANALYSIS; SAMPLE INJECTION; MICROCHIP; SEPARATION; SYSTEMS; MINIATURIZATION; INTEGRATION; PERFORMANCE AB Glass microchips are fabricated to demonstrate two-dimensional spatial confinement of ions and fluids using electrokinetic forces. Neutral and charged molecular samples can be electrokinetically focused to widths as narrow as 3.3 mu m in a 18 mu m long by 18 mu m wide chamber. The electrokinetic focusing characteristics are tested using cationic, neutral, and anionic samples to evaluate the influence of electric fields on the sample stream. Focusing is achieved using electrophoresis, electroosmosis, or a combination of the two. In addition, concentration enhancement is observed in the focusing chamber by employing sample stacking, and the focusing chamber is multiplexed to confine spatially more than one sample stream simultaneously. C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. NR 28 TC 151 Z9 153 U1 3 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD AUG 15 PY 1997 VL 69 IS 16 BP 3212 EP 3217 DI 10.1021/ac961093z PG 6 WC Chemistry, Analytical SC Chemistry GA XQ972 UT WOS:A1997XQ97200013 ER PT J AU Barg, E Lal, D Pavich, MJ Caffee, MW Southon, JR AF Barg, E Lal, D Pavich, MJ Caffee, MW Southon, JR TI Beryllium geochemistry in soils: evaluation of Be-10/Be-9 ratios in authigenic minerals as a basis for age models SO CHEMICAL GEOLOGY LA English DT Article DE beryllium geochemistry; authigenic minerals; age models; Be-10/Be-9 ratios; soil ID EROSION; CALIFORNIA; SEDIMENTS; PARTITION; PARTICLES; TERRACES; VALLEY AB Soils contain a diverse and complex set of chemicals and minerals. Being an 'open system', both in the chemical and nuclear sense, soils have defied quantitative nuclear dating. However, based on the published studies of the cosmogenic atmospheric Be-10 in soils, its relatively long half-life (1.5 Ma), and the fact that Be-10 gets quickly incorporated in most soil minerals, this radionuclide appears to be potentially the most useful for soil dating. We therefore studied the natural variations in the specific activities of Be-10 with respect to the isotope Be-9 in mineral phases in eight profiles of diverse soils from temperate to tropical climatic regimes and evaluated the implications of the data for determining the time of formation of soil minerals, following an earlier suggestion [Lal et al., 1991. Development of cosmogenic nuclear methods for the study of soil erosion and formation rates. Current Sci. 61, 636-639.]. We find that the Be-10/Be-9 ratios in both bulk soils and in the authigenic mineral phases are confined within a narrower range than in Be-10 concentrations. Also, the highest Be-10/Be-9 ratios in authigenic minerals are observed at the soil-rock interface as predicted by the model. We present model Be-10/Be-9 ages of the B-horizon and the corresponding soil formation rates for several soil profiles. The present study demonstrates that the Be-10/Be-9 ratios in the authigenic phases, e.g. clay and Fe-hydroxides, can indeed be used for obtaining useful model ages for soils younger than 10-15 Ma. However, the present work has to be pushed considerably further, to take into account more realistic age models in which, for instance, downward transport of Be-10 and clays, and in-situ dissolution of clay minerals at depths, altering the Be-10/Be-9 ratios of the acidic solutions, are included. We show that in the case of younger soils (< 1 Ma) studied here, their Be-10 inventories and Be-10/Be-9 ratios have been significantly disturbed possibly by mixing with transported soils. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,DIV GEOL RES,LA JOLLA,CA 92093. US GEOL SURVEY,NATL CTR,RESTON,VA 22092. LAWRENCE LIVERMORE NATL LAB,CTR ACCELERATOR MASS SPECTROMETRY,LIVERMORE,CA 94551. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 44 TC 37 Z9 41 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD AUG 15 PY 1997 VL 140 IS 3-4 BP 237 EP 258 DI 10.1016/S0009-2541(97)00051-X PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XZ471 UT WOS:A1997XZ47100006 ER PT J AU Rutt, U Diederichs, A Schneider, JR Shirane, G AF Rutt, U Diederichs, A Schneider, JR Shirane, G TI Depth dependence of strain, mosaicity and sharp component in the critical scattering of SrTiO3 SO EUROPHYSICS LETTERS LA English DT Article ID 2 LENGTH SCALES; X-RAY-SCATTERING; ENERGY SYNCHROTRON-RADIATION; MAGNETIC CRITICAL FLUCTUATIONS; TRIPLE-CRYSTAL DIFFRACTOMETER; NEUTRON-SCATTERING; RESOLUTION FUNCTION; LAUE GEOMETRY; HOLMIUM; TERBIUM AB The sharp component observed in the critical scattering above the cubic-to-tetragonal phase transition in SrTiO3 is now generally considered as a surface-related phenomenon. In the present paper, for the first time, the structural difference between the bulk and a skin layer of a highly perfect crystal has been shown quantitatively by diffraction methods. High-resolution measurements have been performed with highly penetrating 121 keV synchrotron radiation X-rays. The lattice parameter d, its fluctuations Delta d/d, the crystal mosaicity and the critical scattering were found to be depth dependent. The two-length-scale behaviour in the critical fluctuations is confined to a skin layer approximately 100 mu m thick and related to an increase in strain. Approaching the crystal surface the lattice parameter decreases by 6.2.10(-5) Angstrom, Delta d/d increases from the bulk value of 5.2.10(-5) to 13.10(-5), the mosaicity increases from 1.0 to 8.2 seconds of are. In addition the critical temperature determined from the temperature dependence of the 1/2(511) reflection at the surface and 150 mu m below, is smaller than the bulk value by 1.7 and 2.4 K, respectively. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Rutt, U (reprint author), DESY,HAMBURGER SYNCHROTRONSTRAHLUNGSLAB HASYLAB,NOTKESTR 85,D-22603 HAMBURG,GERMANY. NR 22 TC 26 Z9 26 U1 1 U2 7 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD AUG 15 PY 1997 VL 39 IS 4 BP 395 EP 400 DI 10.1209/epl/i1997-00539-0 PG 6 WC Physics, Multidisciplinary SC Physics GA XT585 UT WOS:A1997XT58500009 ER PT J AU Crow, JT AF Crow, JT TI Unipolar-current dipoles and other optimum reduced-symmetry multipoles SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Two-dimensional dipole (uniform) fields produced by parallel currents are generally considered to have two symmetry planes, with a current direction reversal in reflection across one plane. Similarly, quadrupoles have four symmetry planes, and so on for higher multipoles. Expansion of the fields of filamentary currents shows that there are lower symmetry multipoles with highly uniform field characteristics. These solutions include configurations in which there is no current reversal across reflection planes, producing unipolar-current dipoles, quadrupoles, and other multipoles. In all cases, the solutions can yield systems that have the best uniformity of field characteristics (minimum undesired multipole content over the largest area) that can be achieved with the number of wires used, although the unipolar systems are less efficient and produce a lower field magnitude for a given current. These optimum solutions are not limited to circular configurations, or to systems with all wire current magnitudes identical. The configurations are easily extended by summation or integration to wire bundles or finite radius conductors. (C) 1997 American Institute of Physics. RP Crow, JT (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 5 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1511 EP 1517 DI 10.1063/1.365949 PG 7 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700002 ER PT J AU Daymond, MR Bourke, MAM VonDreele, RB Clausen, B Lorentzen, T AF Daymond, MR Bourke, MAM VonDreele, RB Clausen, B Lorentzen, T TI Use of Rietveld refinement for elastic macrostrain determination and for evaluation of plastic strain history from diffraction spectra SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID POLYCRYSTALS AB Macrostrain variations in engineering components are frequently examined using neutron diffraction, at both reactors and pulsed sources. It is desirable to minimize the sampling volume in order to maximize the spatial resolution, although this increases the required measurement time. At reactors, macrostrain behavior is inferred from a single lattice reflection (deemed to be representative of the bulk response). At a pulsed source, a complete diffraction pattern is recorded and accordingly it is natural to fit the entire diffraction spectra using a Rietveld [J. Appl. Cryst. 2, 65 (1969)] refinement. This means that an idealized crystal structure is fit to the measured distorted crystal structure, which includes deviation of the measured lattice reflections from the ideal due to elastoplastic strain anisotropies, which are dependent on the particular lattice reflection (hk1) considered. We show that elastic macrostrains calculated from lattice parameter changes in Rietveld refinements (without accounting for hk1 dependent anisotropies) are almost identical to the bulk elastic response and are comparable to the response obtained from a single lattice reflection typically used by practitioners at a steady state source. Moreover good refinements on the complete pattern are obtained with short measurement times compared to what is required for good statistics for single reflections. By incorporating a description of the elastic strain anisotropy expected in cubic materials into the Rietveld code, an empirical prediction of plastic strain history is possible. The validity of these arguments is demonstrated by analysis of a uniaxial tensile load test and a reanalysis of previously reported data taken on a deformed stainless steel ring. The plastic strain predictions compare favorably with a finite element model. (C) 1997 American Institute of Physics. C1 RISO NATL LAB,DEPT MAT,DK-4000 ROSKILDE,DENMARK. RP Daymond, MR (reprint author), LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545, USA. RI Clausen, Bjorn/B-3618-2015; OI Clausen, Bjorn/0000-0003-3906-846X; Daymond, Mark/0000-0001-6242-7489 NR 17 TC 215 Z9 215 U1 2 U2 25 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1554 EP 1562 DI 10.1063/1.365956 PG 9 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700009 ER PT J AU Kim, CU Morris, JW Lee, HM AF Kim, CU Morris, JW Lee, HM TI Kinetics of electromigration-induced edge drift in Al-Cu thin-film interconnects SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ALUMINUM FILMS; MECHANISMS; VELOCITY; FAILURE; LINES AB This article employs a one-dimensional diffusion model to study the phenomenon of electromigration-induced edge drift in a finite, Al-Cu thin-film conductor. Edge drift is caused by the accumulation of vacancies at the negative (upstream) terminal of the conductor as Al diffuses with the electrical current. When the Cu content exceeds its solubility limit, grain boundaries are decorated with Al2Cu precipitates, which must be dissolved before significant Al diffusion occurs. Assuming one-dimensional flow in a homogeneous, polygranular film, we compute the rate of growth of the precipitate-free zone at the upstream terminal, and estimate the incubation time for the onset of edge drift. The results predict an incubation time that increases with the grain size and the initial Cu content, and decreases with the square of the current density. The incubation time is inversely proportional to the ''electromigration diffusivity'', D-E=D-B(Cu) delta Z*(Cu), the product of the grain boundary diffusivity of Cu, the effective grain boundary thickness, and the effective valence of the Cu ion. The results are used to compare a number of prior experimental studies, which are shown (with one exception) to produce consistent values for D-E. An analysis of the experimental results suggests that edge drift begins almost as soon as the precipitate-free zone length exceeds the ''Blech length'' for the line, suggesting that the presence of Al2Cu precipitates in the grain boundaries is essential to retard Al electromigration. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & ENGN,BERKELEY,CA 94720. RI Lee, Hyuck Mo/C-1994-2011 NR 35 TC 4 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1592 EP 1598 DI 10.1063/1.365948 PG 7 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700013 ER PT J AU Mirkarimi, PB Medlin, DL McCarty, KF Dibble, DC Clift, WM Knapp, JA Barbour, JC AF Mirkarimi, PB Medlin, DL McCarty, KF Dibble, DC Clift, WM Knapp, JA Barbour, JC TI The synthesis, characterization, and mechanical properties of thick, ultrahard cubic boron nitride films deposited by ion-assisted sputtering SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PULSED-LASER DEPOSITION; ELASTIC-MODULUS; HARDNESS; DIAMOND; BEAM; CERAMICS; SILICON; STRESS; GROWTH; MODEL AB Significant ion irradiation is needed during growth to synthesize cubic boron nitride (cBN) films. This results in large film stresses, which have limited cBN film thicknesses to only a few hundred nm and represents a significant barrier in the development of cBN film technology. Using a new hybrid deposition technique, we have synthesized cubic BN films up to 700 nm (0.7 mu m) thick. A compositional and structural analysis of the films using several standard characterization techniques confirms that relatively thick polycrystalline films with a high cBN content were synthesized, Thicker cBN films enable hardness measurements to be undertaken without major substrate effects. Nanoindentation measurements yield hardness values for the cubic BN films up to 60-70 GPa, which are greater than values measured for bulk cBN. The measured elastic modulus was observed to be lower than the bulk, and this can be accounted for by an elastic deformation of the silicon substrate. The mechanical properties of the cubic BN films are discussed with reference to other ultrahard thin films such as diamond and diamondlike carbon. (C) 1997 American Institute of Physics. C1 SANDIA NATL LABS, LIVERMORE, CA 94550 USA. SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 61 TC 81 Z9 81 U1 2 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1617 EP 1625 DI 10.1063/1.365961 PG 9 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700016 ER PT J AU Warren, WL Vanheusden, K Tallant, DR Seager, CH Sun, SS Evans, DR Dennis, WM Soininen, E Bullington, JA AF Warren, WL Vanheusden, K Tallant, DR Seager, CH Sun, SS Evans, DR Dennis, WM Soininen, E Bullington, JA TI Atomic level stress and light emission of Ce activated SrS thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB We find that the Ce3+ ion in polycrystalline sputtered SrS:Ce thin films resides in a distorted octahedral environment, as opposed to the cubic host environment. Using electron paramagnetic resonance and x-ray diffraction analysis, we show that the degree of axial distortion is related to the preferential growth direction of the SrS films. To first order, the blue-emission properties (emission wavelength and decay times) of the SrS:Ce films do not appear to be affected by the amount of distortion in the local Ce3+ environment. (C) 1997 American Institute of Physics. C1 PLANAR AMER INC,BEAVERTON,OR 97006. UNIV GEORGIA,DEPT PHYS & ASTRON,ATHENS,GA 30602. PLANAR INT LTD,FIN-02200 ESPOO,FINLAND. ADV MAT & MFG PROCESSES ECON COMPETITIVENESS,ALBUQUERQUE,NM 87106. RP Warren, WL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1812 EP 1814 DI 10.1063/1.366284 PG 3 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700043 ER PT J AU Bullock, AB Bolton, PR Mayer, FJ AF Bullock, AB Bolton, PR Mayer, FJ TI Time-integrated reflectivity of laser-induced back-ablated aluminum thin film targets SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DEPOSITION AB A study of the time-integrated reflectivity of Al targets during laser-induced back ablation by 1064 nm, 10 ns laser pulses is reported. The Al target reflectance data is analyzed using a model which includes not only Al surface removal but also the possible production of Al plasma. Calculations based on a sharp Al film ablation fluence (J(th) approximate to 710 mJ/cm(2)) threshold agree with the reflectance data. Plasma reflectance contribution is found to be negligible for plasma electron densities of less than 0.3 critical density. (C) 1997 American Institute of Physics. C1 MAYER APPL RES INC, ANN ARBOR, MI 48103 USA. RP LAWRENCE LIVERMORE NATL LAB, POB 808, LIVERMORE, CA 94551 USA. NR 13 TC 17 Z9 17 U1 1 U2 2 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 AUG 15 PY 1997 VL 82 IS 4 BP 1828 EP 1831 DI 10.1063/1.366289 PG 4 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700046 ER PT J AU Doughty, C Gorbatkin, SM Berry, LA AF Doughty, C Gorbatkin, SM Berry, LA TI Spatial distribution of Cu sputter ejected by very low energy ion bombardment SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CYCLOTRON-RESONANCE PLASMA; MICROWAVE PLASMA; DEPOSITION; ATOMS AB Filling of submicron width trenches with Cu from a highly ionized plasma is sensitive to both the directionality of the depositing flux and reflection and resputtering at the film surface. The spatial distributions of Cu atoms sputtered by He+, Ar+, and Xe+ ions incident at 30 degrees, 45 degrees and 60 degrees and over an ion energy range of similar to 55-600 eV have been investigated. In all cases, the distribution is forward directed and cannot be described by a cosine distribution about the surface normal. Decreasing energy, increasing angles of incidence, and increasing ion mass yield more forward directed distributions. For similar to 55 eV Ar+ incident at 60 degrees, similar to 85% of the resputtered flux is in the forward direction. From these distributions, in a 50% ionized physical vapor deposition system the depositing flux due to forward directed resputtering is estimated to be of the same order of magnitude as the neutral flux. (C) 1997 American Institute of Physics. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 25 TC 12 Z9 12 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1868 EP 1875 DI 10.1063/1.365991 PG 8 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700052 ER PT J AU Koynov, S Topf, M Fischer, S Meyer, BK Radojkovic, P Hartmann, E LilientalWeber, Z AF Koynov, S Topf, M Fischer, S Meyer, BK Radojkovic, P Hartmann, E LilientalWeber, Z TI Structural investigations of GaN grown by low-pressure chemical vapor deposition on 6H-SiC and Al2O3 from GaCl3 and NH3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRON-MICROSCOPY; SAPPHIRE; EPITAXY; FILMS AB GaN films grown on (0001) 6H-SiC and (0001) Al2O3 substrates using low-pressure chemical vapor deposition with GaCl3 and NH3 as precursors are comparatively explored by optical, scanning tunneling, and transmission electron microscopy. Independent of the substrate material used, the surface of the GaN layers is covered by hexagonally shaped islands. For GaN on 6H-SiC, the islands are larger in diameter (approximate to 50 mu m) and rather uniformly distributed. An atomically flat interface is observed for GaN on Al2O3 in contrast to GaN grown on 6H-SiC, where the interface is characterized by large steps. For both substrates, faceted holes (named as pinholes) are observed in near-surface regions of the GaN layers occurring with a density of about 7 x 10(8) cm((-2)). No unequivocal correlation between the density of pinholes and the density of threading dislocations (approximate to 1.6 x 10((10)) cm((-2)) for GaN/Al2O3 and approximate to 4 x 10(9) cm((-2)) for GaN/6H-SiC) can be found, Rather, different types of defects are identified to be correlated with the pinholes, implying a dislocation-independent mechanism for the pinhole formation. Despite the small lattice mismatch between GaN and 6H-SiC, the pronounced original surface roughness of this substrate material is believed to account for both the marked interfacial roughness and the still existing high density of threading dislocations. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. BULGARIAN ACAD SCI,CLSENES,BU-1784 SOFIA,BULGARIA. RP Koynov, S (reprint author), TECH UNIV MUNICH,PHYS DEPT E16,STM GRP,D-85748 GARCHING,GERMANY. RI Liliental-Weber, Zuzanna/H-8006-2012; Meyer, Bernhard/Q-9413-2016 NR 26 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1890 EP 1895 DI 10.1063/1.365994 PG 6 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700055 ER PT J AU Molenbroek, EC Mahan, AH Gallagher, A AF Molenbroek, EC Mahan, AH Gallagher, A TI Mechanisms influencing ''hot-wire'' deposition of hydrogenated amorphous silicon SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID A-SI-H; DEVICE QUALITY; SILANE; DECOMPOSITION; FILMS AB Intrinsic hydrogenated amorphous silicon (a-Si:H) has been deposited using a hot tungsten filament in pure silane to drive the deposition chemistry-the ''hot-wire'' deposition method. The electronic and infrared properties of the film have been measured as a function of deposition parameters, leading to three principal conclusions. First, to obtain a high quality material, the Si atoms evaporated from the filament (distance L from the substrate) must react with silane (density n(s)) before reaching the substrate; this requires n(s)L greater than a critical value. Second, radical-radical reactions cause deterioration of him properties at high values of G(n(s)L),(3) where G is the film growth rate; this requires G(n(s)L)3 less than a critical value. Finally, the film quality is a function of G, and as G is increased the substrate temperature must be correspondingly increased to obtain high film quality. By optimizing these parameters, we have produced films with excellent electronic properties (e.g., ambipolar diffusion length >200 nm) at >5 nm/s deposition rate. Based on these insights, formulas are also given for optimizing film properties in multiple-filament geometries and in diluted silane. (C) 1997 American Institute of Physics. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. UNIV COLORADO,JILA,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NR 16 TC 51 Z9 51 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1997 VL 82 IS 4 BP 1909 EP 1917 DI 10.1063/1.365998 PG 9 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700059 ER PT J AU Carini, G Crupi, V DAngelo, G Majolino, D Migliardo, P Melnichenko, YB AF Carini, G Crupi, V DAngelo, G Majolino, D Migliardo, P Melnichenko, YB TI Relaxation dynamics of H-bonded liquids confined in porous silica gels by Rayleigh wing spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LIGHT-SCATTERING; VIBRATIONAL-RELAXATION; GLASS-TRANSITION; SELF-DIFFUSION; SHAPE; WATER AB Reorientational dynamics of neat liquid propylene glycol molecules is compared with that of confined molecules in 25 and 75 Angstrom pores of a sol-gel porous glass by means of depolarized light-scattering spectroscopy. The experimental spectra. performed as a function of temperature, show unambiguously the slowing down of the collective reorientational processes triggered by the confinement effects. Such results confirm the main role played by the strong dipolar interactions on the dynamics of hydrogen-bonded liquids diffusing within nanoscopic spherical pores. (C) 1997 American Institute of Physics. C1 INFM, I-98166 SANT AGATA, MESSINA, ITALY. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RP Carini, G (reprint author), UNIV MESSINA, DIPARTIMENTO FIS, CDA PAPARDO, POB 55, I-98166 SANT AGATA, MESSINA, ITALY. OI MAJOLINO, Domenico/0000-0002-2934-2587 NR 35 TC 46 Z9 46 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 1997 VL 107 IS 7 BP 2292 EP 2299 DI 10.1063/1.474605 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ332 UT WOS:A1997XQ33200015 ER PT J AU Schatz, GC Papaioannou, A Pederson, LA Harding, LB Hollebeek, T Ho, TS Rabitz, H AF Schatz, GC Papaioannou, A Pederson, LA Harding, LB Hollebeek, T Ho, TS Rabitz, H TI A global A-state potential surface for H2O: Influence of excited states on the O(D-1)+H-2 reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; ISOTOPIC BRANCHING RATIO; GAUSSIAN-BASIS SETS; ENERGY SURFACES; ELECTRIC PROPERTIES; REAGENT ROTATION; + H-2; DYNAMICS; PHOTODISSOCIATION; DISTRIBUTIONS AB In this article a global potential energy surface for the 1A'' state of H2O based on application of the reproducing kernel Hilbert space interpolation method to high quality nb initio results is presented. The resulting 1A'' surface is used in conjunction with a previously determined 1A' surface to study the O(D-1) + H-2(HD,D-2) reaction dynamics, with emphasis on the influence of the 1 A '' excited state on measurable properties such as the reactive cross sections, rate coefficients, and product state distributions. There is a reactive threshold of about 2 kca/mol on the 1A'' surface, and even at 5 kcal/mol, the 1A '' reactive cross section is only a small fraction (similar to 20%) of the barrierless 1A'. However, the 1A'' surface populates very specific product vibrational states (v'= 3-4) and lives strongly backward peaked differential cross sections, so certain types of measurements are quite sensitive to the presence of this excited stare. In particular, better agreement is found with experimental vibrational and angular distributions with 1A '' included, especially at translational energies of 4 kcal/mol and above. A rough estimate of the influence of the 2A' surface indicates that this state also makes an important contribution to vibrational and angular distributions at high energies. The 1A'' and 2A' surfaces also measurably affect the energy dependence of the integral cross sections at energies above 2 kcal/mol, and the temperature dependence of thermal rate coefficients for O(D-1) + H-2 at temperatures of 1000 K and above. (C) 1997 American Institute of Physics. C1 ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. PRINCETON UNIV, DEPT CHEM, PRINCETON, NJ 08544 USA. RP Schatz, GC (reprint author), NORTHWESTERN UNIV, DEPT CHEM, 2145 SHERIDAN RD, EVANSTON, IL 60208 USA. NR 47 TC 128 Z9 129 U1 3 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 1997 VL 107 IS 7 BP 2340 EP 2350 DI 10.1063/1.474614 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ332 UT WOS:A1997XQ33200020 ER PT J AU Shkrob, IA Trifunac, AD AF Shkrob, IA Trifunac, AD TI Spin-polarized H/D atoms and radiation chemistry in amorphous silica SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INDUCED MAGNETIC-POLARIZATION; SELF-TRAPPED HOLES; INTERFACE STATES; WATER RADIOLYSIS; VITREOUS SILICA; FUSED-SILICA; H-ATOM; SIO2; ELECTRON; DIFFUSION AB Time-resolved pulsed electron paramagnetic resonance (EPR) was used to study spin-polarized mobile H and D atoms in radiolysis of silica glass containing similar to 1200 ppm of OH or OD groups, The EPR spectra of the H/D atoms indicate the occurrence of CIDEP in reactions of H/D atoms with radiolytically induced metastable spin centers. The EPR kinetics observed at 180-530 K exhibit fast growth and slow decay. The slow component (E-a = 15-18 kJ/mol) is due to diffusion-controlled scavenging of H and D atoms by defects. For D atoms, this scavenging is 1.1-1.5 times slower than for H atoms; the formation rate of spin polarization is the same for H and D atoms, Below T-c = 320 +/- 20 K, the decay kinetics can be fit by [H](1) = [H](0) exp[-(k(s)t)(beta)], with beta approximate to T/T-c: above T-c, beta approximate to 1, This behavior is indicative of dispersive diffusive transport of the H/D atoms through the glass network. The fast component with E-a = 6-8 kJ/mol is due to rapid decay of (1 mobile spin partner of the H/D atoms, which we assume to be a polaron, in reactions with OH groups. It is argued that the large difference in the EPR signals from H and D atoms, relative to the concentration of the OH/OD defects (approximately 4-8 times), must be due to the substantial isotope effect on radiolytic yield of the H/D atoms (alpha similar to 1.5 +/- 0.2). The most likely reaction that can yield such an isotope effect is recombination of metastable protons with electrons. Our result seems to indicate that the latter reaction is the main route to the H atoms in room-temperature silica. At low temperatures, the H atoms are formed mainly due to dissociation of the OH defects following their reaction with triplet excitons, and alpha approximate to 1. (C) 1997 American Institute of Physics. RP Shkrob, IA (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 75 TC 20 Z9 20 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 1997 VL 107 IS 7 BP 2374 EP 2385 DI 10.1063/1.474580 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ332 UT WOS:A1997XQ33200024 ER PT J AU vanMourik, T Dunning, TH AF vanMourik, T Dunning, TH TI Ab initio characterization of the structure and energetics of the ArHF complex SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR WAVE-FUNCTIONS; CONFIGURATION-INTERACTION CALCULATIONS; GAUSSIAN-BASIS SETS; DER-WAALS CLUSTERS; BOUND-STATE CALCULATIONS; DIFFERENCE-FREQUENCY-GENERATION; BENCHMARK CALCULATIONS; OVERTONE SPECTROSCOPY; INTERMOLECULAR FORCES; DIATOMIC HYDRIDES AB The ArHF complex has been investigated using correlation consistent basis sets at several levels of theory, including Moller-Plesset perturbation theory (MP2, MP3, MP4) and coupled cluster techniques [CCSD, CCSD(T)]. The three stationary points (the primary linear Ar-HF minimum, the secondary linear Ar-FH minimum, and the interposed transition state TS) on the counterpoise-corrected potential energy surface have been characterized. Calculations with the aug-cc-pV5Z basis set predict D-e for the Ar-HF minimum to be (with estimated complete basis set limits in parentheses) -215 (-218) cm(-1) for MP3 and -206 (-211) cm(-1) for CCSD(T). For the Ar-FH minimum and the TS, calculations with the d-aug-cc-pVQZ sets predict D-e's (and CBS limits) of -97 (-99) and -76 (-78) cm(-1) (MP4) and -93 (-94) and -75 (-76) cm(-1) [CCSD(T)], respectively. The corresponding values for the H6(4,3,2) potential of Hutson [J. Chem. Phys. 96, 6752 (1992)] are -211.1 +/- 4 cm(-1), -108.8 +/- 10 cm(-1), and -82.6 +/- 10 cm(-1). While the agreement of our CCSD(T) estimate with Hutson's value is excellent for the global minimum, it is less so for the other two stationary points, suggesting that the H6(4,3,2) potential may be too attractive around the secondary minimum and the transition state. (C) 1997 American Institute of Physics. RP vanMourik, T (reprint author), PACIFIC NW LAB, ENVIRONM MOL SCI LAB, POB 999, RICHLAND, WA 99352 USA. RI van Mourik, Tanja/A-4007-2008 NR 63 TC 53 Z9 53 U1 3 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 1997 VL 107 IS 7 BP 2451 EP 2462 DI 10.1063/1.475148 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ332 UT WOS:A1997XQ33200034 ER PT J AU Bonisch, G Blindheim, J Bullister, JL Schlosser, P Wallace, DWR AF Bonisch, G Blindheim, J Bullister, JL Schlosser, P Wallace, DWR TI Long-term trends of temperature, salinity, density, and transient tracers in the central Greenland Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DEEP-WATER FORMATION; NORWEGIAN SEAS; ARCTIC-OCEAN; TRITIUM; RATES; CONVECTION; ICELAND AB We present long-term observations of temperature, salinity, tritium/He-3, chlorofluorocarbon-11 (CFC11), and chlorofluorocarbon-12 (CFC 12) for the central Greenland Gyre. The time series span the periods between 1952 and 1994 (temperature), 1981 and 1994 (salinity), 1972 and 1994 (tritium/He-3), and 1982 and 1994 (CFCs). The correlation between hydrographic and transient tracer data indicates that low temperatures in the deep water in the early 1950s and between 1960 and 1980 reflect periods of higher deep water formation rates whereas periods of increasing temperatures in the late 1950s and between 1980 and 1994 are related to low deep water formation rates. However, the transient tracer observations obtained in the 1980s and early 1990s indicate that even during periods of low deep water formation, some water from the upper water column contributed to deep water formation between 1980 and 1994. In 1994, the deep water reached temperatures and salinities of -1.149 degrees C and 34.899, respectively, and no longer fits most of the classical definitions of Greenland Sea Deep Water (-1.29 degrees C < Theta < -1.0 degrees C, 34.58 < S < 34.90). The temperature increase in the water column between 200 and 2000m depth between 1980 and 1994 corresponds to an average heating rate of about 5 W m(-2) over this period, resulting in a decrease in density. The 13-year warming could be balanced by intensive cooling in two winters. The surface salinity steadily increased from 34.50 in 1991 to 34.85 in 1994. C1 INST MARINE RES,N-5024 BERGEN,NORWAY. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV OCEANOG & ATMOSPHER SCI,UPTON,NY 11973. COLUMBIA UNIV,DEPT EARTH & ENVIRONM SCI,NEW YORK,NY. RP Bonisch, G (reprint author), LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964, USA. RI Schlosser, Peter/C-6416-2012 OI Schlosser, Peter/0000-0002-6514-4203 NR 35 TC 44 Z9 45 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD AUG 15 PY 1997 VL 102 IS C8 BP 18553 EP 18571 DI 10.1029/97JC00740 PG 19 WC Oceanography SC Oceanography GA XR356 UT WOS:A1997XR35600003 ER PT J AU Sandlin, MS Butt, DP Taylor, TN Petrovic, JJ AF Sandlin, MS Butt, DP Taylor, TN Petrovic, JJ TI Aqueous zeta potentials of molybdenum disilicide SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID COMPOSITES RP Sandlin, MS (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 11 TC 4 Z9 4 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD AUG 15 PY 1997 VL 16 IS 16 BP 1336 EP 1338 DI 10.1023/A:1018564000613 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA XT183 UT WOS:A1997XT18300004 ER PT J AU Ozawa, M Suzuki, S Loong, CK Thiyagarajan, P AF Ozawa, M Suzuki, S Loong, CK Thiyagarajan, P TI The zeta-potential and microstructure of ZrO2 sol derived from a hydrolysis method SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID ZIRCONIA; PARTICLES C1 ARGONNE NATL LAB,IPNS,ARGONNE,IL 60439. RP Ozawa, M (reprint author), NAGOYA INST TECHNOL,CRL,TAJIMI,GIFU 507,JAPAN. NR 16 TC 4 Z9 4 U1 0 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD AUG 15 PY 1997 VL 16 IS 16 BP 1360 EP 1362 DI 10.1023/A:1018580404248 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA XT183 UT WOS:A1997XT18300012 ER PT J AU Mian, IS AF Mian, IS TI Comparative sequence analysis of ribonucleases HII, III, II PH and D SO NUCLEIC ACIDS RESEARCH LA English DT Article ID DNA-POLYMERASE-I; PROTEIN PHOSPHATASE FUNCTIONS; TRANSFER-RNA PRECURSORS; HIDDEN MARKOV-MODELS; DSRNA BINDING DOMAIN; ESCHERICHIA-COLI; DROSOPHILA STAUFEN; S-PHASE; GENE; EXORIBONUCLEASES AB Escherichia coli ribonucleases (RNases) HII, III, II, PH and D have been used to characterise new and known viral, bacterial, archaeal and eucaryotic sequences similar to these endo- (Hit and III) and exoribonucleases (It, PH and D), Statistical models, hidden Markov models (HMMs), were created for the RNase HII, III, II, PH and D families as well as a double-stranded RNA binding domain present in RNase III, Results suggest that the RNase D family, which includes Werner syndrome protein and the 100 kDa antigenic component of the human polymyositis scleroderma (PMSCL) autoantigen, is a 3'-->5' exoribonuclease structurally and functionally related to the 3'-->5' exodeoxyribonuclease domain of DNA polymerases, Polynucleotide phosphorylases and the RNase PH family, which includes the 75 kDa PMSCL autoantigen, possess a common domain suggesting similar structures and mechanisms of action for these 3'-->5' phosphorolytic enzymes, Examination of HMM-generated multiple sequence alignments for each family suggest amino acids that may be important for their structure, substrate binding and/or catalysis. C1 UNIV CALIF SANTA CRUZ,SINSHEIMER LABS,SANTA CRUZ,CA 95064. RP Mian, IS (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,MAIL STOP 29-100,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NIGMS NIH HHS [GM17129] NR 64 TC 160 Z9 160 U1 0 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD AUG 15 PY 1997 VL 25 IS 16 BP 3187 EP 3195 DI 10.1093/nar/25.16.3187 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XR701 UT WOS:A1997XR70100001 PM 9241229 ER PT J AU Shen, BH Nolan, JP Sklar, LA Park, MS AF Shen, BH Nolan, JP Sklar, LA Park, MS TI Functional analysis of point mutations in human flap endonuclease-1 active site SO NUCLEIC ACIDS RESEARCH LA English DT Article ID NUCLEOTIDE EXCISION-REPAIR; STRAND DNA-REPLICATION; SACCHAROMYCES-CEREVISIAE; 3' EXONUCLEASE; POLYMERASE; COMPLETION; PROTEINS; CLEAVAGE; DOMAIN; FAMILY AB Human flap endonuclease-l (hFEN-1) is highly homologous to human XPG, Saccharomyces cerevisiae RAD2 and S.cerevisiae RTH1 and shares structural and functional similarity with viral exonucleases such as T4 RNase H, T5 exonuclease and prokaryotic DNA polymerase 5' nucleases. Sequence alignment of 18 structure-specific nucleases revealed two conserved nuclease domains with seven conserved carboxyl residues and one positively charged residue, In a previous report, we showed that removal of the side chain of each individual acidic residue results in complete loss of flap endonuclease activity. Here we report a detailed analysis of substrate cleavage and binding of these mutant enzymes as well as of an additional site-directed mutation of a conserved acidic residue (E160), We found that the active mutant (R103A) has substrate binding and cleavage activity indistinguishable from the wild type enzyme. Of the inactive mutants, one (D181A) has substrate binding properties comparable to the wild type, while three others (D34A, D86A and E160A) bind with lower apparent affinity (2-, 9- and 18-fold reduced, respectively), The other mutants (D158A, D179A and D233A) have no detectable binding activity, We interpret the structural implications of these findings using the crystal structures of related enzymes with the flap endonuclease activity and propose that there are two metal ions (Mg2+ or Mn2+) in hFEN enzyme, These two metal coordinated active sites are distinguishable but interrelated. One metal site is directly involved in nucleophile attack to the substrate phosphodiester bonds while the other may stabilize the structure for the DNA substrate binding. These two sites may be relatively close since some of carboxyl residues can serve as ligands for both sites. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. CITY HOPE NATL MED CTR,DEPT CELL & TUMOR BIOL,DUARTE,CA 91010. UNIV NEW MEXICO,SCH MED,ALBUQUERQUE,NM 87131. FU NCI NIH HHS [CA71630]; NCRR NIH HHS [RR01315] NR 28 TC 84 Z9 88 U1 1 U2 8 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD AUG 15 PY 1997 VL 25 IS 16 BP 3332 EP 3338 DI 10.1093/nar/25.16.3332 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XR701 UT WOS:A1997XR70100022 PM 9241249 ER PT J AU Eimerl, D Auerbach, JM Barker, CE Milam, D Milonni, PW AF Eimerl, D Auerbach, JM Barker, CE Milam, D Milonni, PW TI Multicrystal designs for efficient third-harmonic generation SO OPTICS LETTERS LA English DT Article ID FREQUENCY AB Efficient frequency tripling of high-fluence, narrow-band laser pulses is routinely accomplished with a doubling crystal and a sum-frequency mixer. The addition of a second mixer can dramatically improve conversion efficiencies for the large bandwidths of interest for inertial confinement fusion. Designs that involve two doublers similarly offer a higher dynamic range of conversion efficiency versus intensity than the usual two-crystal design. (C) 1997 Optical Society of America. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Eimerl, D (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 5808,LIVERMORE,CA 94550, USA. NR 11 TC 51 Z9 60 U1 4 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 15 PY 1997 VL 22 IS 16 BP 1208 EP 1210 DI 10.1364/OL.22.001208 PG 3 WC Optics SC Optics GA XP167 UT WOS:A1997XP16700002 PM 18185796 ER PT J AU Richman, BA Bisson, SE Trebino, R Mitchell, MG Sidick, E Jacobson, A AF Richman, BA Bisson, SE Trebino, R Mitchell, MG Sidick, E Jacobson, A TI Achromatic phase matching for tunable second-harmonic generation by use of a grism SO OPTICS LETTERS LA English DT Article ID FEMTOSECOND PULSES AB Achromatic phase matching (APM) involves dispersing the light entering a nonlinear-optical crystal so that a wide range of wavelengths is simultaneously phase matched. Using an APM arrangement consisting of a grism (a grating on the surface of a prism) and three prisms, optimized to match a second-harmonic crystal phase-matching angle versus wavelength to high order, we efficiently doubled tunable fundamental light near 650 nm with a bandwidth of >95 nm by use of a 4-mm type I beta-barium berate crystal. APM uses no moving parts, and unlike previous APM designs, ours avoids lenses and hence is easy to align and insensitive to translational misalignment of the beam. (C) 1997 Optical Society of America. C1 CVI LASER CORP,LIVERMORE,CA 94550. RP Richman, BA (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,M-S 9051,LIVERMORE,CA 94551, USA. NR 9 TC 17 Z9 17 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 15 PY 1997 VL 22 IS 16 BP 1223 EP 1225 DI 10.1364/OL.22.001223 PG 3 WC Optics SC Optics GA XP167 UT WOS:A1997XP16700007 PM 18185801 ER PT J AU Sitko, P Quinn, JJ Marinescu, DC AF Sitko, P Quinn, JJ Marinescu, DC TI Quantum Hall spherical systems: The filling fraction SO PHYSICAL REVIEW B LA English DT Article ID FLUID AB Within the recently formulated composite fermion hierarchy the filling fraction of a spherical quantum Hall system is obtained when it can be expressed as an odd or even denominator fraction. A plot of nu(2S/N-1) as a function of 2S for a constant number of particles (up to N = 10 001) exhibits a structure of the fractional quantum Hall effect. It is confirmed that nu(e) + nu(h) = 1 for all particle-hole conjugate systems, except systems with N-e = N-h and N-e = N-h +/- 1. C1 WROCLAW TECH UNIV,INST PHYS,PL-50370 WROCLAW,POLAND. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Sitko, P (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3606 EP 3608 DI 10.1103/PhysRevB.56.3606 PG 3 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400024 ER PT J AU MelendezLira, M Lorentzen, JD Menendez, J Windl, W Cave, NG Liu, R Christiansen, JW Theodore, ND Candelaria, JJ AF MelendezLira, M Lorentzen, JD Menendez, J Windl, W Cave, NG Liu, R Christiansen, JW Theodore, ND Candelaria, JJ TI Microscopic carbon distribution in Si1-yCy alloys: A Raman scattering study SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; SI1-X-YGEXCY ALLOYS; SILICON; GROWTH; LAYERS; SI AB Si1-yCy alloys grown by solid-phase epitaxy of carbon-implanted Si were investigated with Raman spectroscopy A comparison between the experimental Raman spectrum and the spectrum predicted from nb initio calculations shows that the carbon distribution in these samples is more randomized than in similar alloys grown by molecular-beam epitaxy. It is argued that epitaxial, layer-by-layer growth promotes the formation of ordered Si-C structures. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. MOTOROLA INC,MAT RES & STRATEG TECHNOL,MESA,AZ 85202. MOTOROLA INC,SEMICOND TECHNOL LAB,AUSTIN,TX 78721. RP MelendezLira, M (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287, USA. RI Menendez, Jose/C-1034-2009; Windl, Wolfgang/C-7255-2012 OI Menendez, Jose/0000-0001-8739-9197; Windl, Wolfgang/0000-0001-5892-0684 NR 16 TC 13 Z9 13 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3648 EP 3650 DI 10.1103/PhysRevB.56.3648 PG 3 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400035 ER PT J AU Lucas, CA Markovic, NM Ross, PN AF Lucas, CA Markovic, NM Ross, PN TI Electrochemical deposition of copper onto Pt(111) in the presence of (bi)sulfate anions SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-SCATTERING; SCANNING-TUNNELING-MICROSCOPY; UNDERPOTENTIAL DEPOSITION; SULFURIC-ACID; ATOMIC-STRUCTURE; ELECTRODE; SURFACE; ADSORPTION; GOLD(111); ADLAYERS AB Using in situ x-ray diffraction we have studied the underpotential deposition (UPD) of copper onto a Pt(111) electrode in sulfuric acid. Deposition occurs in a two-stage process; close to a full monolayer of Cu being preceded by a (root 3X root 3)R30 degrees structure that consists of both Cu and (bi)sulfate anions and is similar to the structure observed on the Au(111) electrode. Utilizing anomalous scattering methods we can accurately determine the Cu coverage during UPD and propose structural models based on crystal truncation rod measurements. C1 UNIV LIVERPOOL,DEPT PHYS,OLIVER LODGE LAB,LIVERPOOL L69 7ZE,MERSEYSIDE,ENGLAND. RP Lucas, CA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. OI Lucas, Christopher/0000-0001-5743-3868 NR 19 TC 32 Z9 32 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3651 EP 3654 DI 10.1103/PhysRevB.56.3651 PG 4 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400036 ER PT J AU Ye, YY Chan, CT Ho, KM AF Ye, YY Chan, CT Ho, KM TI Structural and electronic properties of the martensitic alloys TiNi, TiPd, and TiPt SO PHYSICAL REVIEW B LA English DT Article ID NORM-CONSERVING PSEUDOPOTENTIALS; CRYSTAL-STRUCTURE; X-RAY; NITI; TRANSFORMATION; DENSITY; B2-NITI; B2-PDTI; METALS AB The electronic and structural properties for TiNi, TiPd, and TiPt are studied using first-principles total energy calculations. For each alloy, the structural parameters for a few structural phases are found from energy and force calculations. In each case, we found that the ground state martensitic phase (B19/B19') is indeed lower in energy than the high temperature B2 phase. In all three alloys, the lowering in energy of the B19/B19' structure is associated with the electronic properties such as lowering of the density of states at the Fermi level at the Ti site, and the broadening of the transition-metal d bands in the B19/B19' phase compared with the B2 phase. C1 HONG KONG UNIV SCI & TECHNOL,DEPT PHYS,HONG KONG,HONG KONG. IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. US DOE,AMES LAB,AMES,IA 50011. RP Ye, YY (reprint author), WUHAN UNIV,CTR ANAL & TESTING,WUHAN 430072,PEOPLES R CHINA. NR 37 TC 84 Z9 86 U1 3 U2 16 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3678 EP 3689 DI 10.1103/PhysRevB.56.3678 PG 12 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400041 ER PT J AU Yu, ZG Saxena, A Bishop, AR AF Yu, ZG Saxena, A Bishop, AR TI Excitons in quasi-one-dimensional organics: Strong correlation approximation SO PHYSICAL REVIEW B LA English DT Article ID LIGHT-EMITTING-DIODES; PHOTOINDUCED CHARGE-TRANSFER; CONJUGATED POLYMERS; CONDUCTING POLYMERS; POLY(P-PHENYLENE VINYLENE); ELECTRON CORRELATION; OPTICAL GAP; BAND-GAP; POLYACETYLENE; SINGLET AB An exciton theory for quasi-one-dimensional organic materials is developed in the framework of the Su-Schrieffer-Heeger Hamiltonian augmented by short-range extended Hubbard interactions. Within a strong electron-electron correlation approximation, the exciton properties are extensively studied. Using scattering theory, we analytically obtain the exciton energy and wave function and derive a criterion for the existence of a B-u exciton. We also systematically investigate the effect of impurities on the coherent motion of an exciton; The coherence is measured by a suitably defined electron-hole correlation function; It is shown that, for impurities with an on-site potential, a crossover behavior will occur if the impurity strength is comparable to the bandwidth of the exciton, corresponding to exciton localization. For a charged impurity with a spatially extended potential, in addition to localization the exciton will dissociate into an uncorrelated electron-hole pair when the impurity is sufficiently strong to overcome the Coulomb interaction which binds the electron-hole pair. Interchain coupling effects are also discussed by considering two polymer chains coupled through nearest-neighbor interchain hopping t(perpendicular to) and interchain Coulomb interaction V-perpendicular to. Within the t matrix scattering formalism, for every center-of-mass momentum, we find two poles determined only by V-perpendicular to which correspond to the interchain excitons, and four poles only involving intrachain Coulomb V, which are intrachain excitons. The interchain exciton wave function is analyzed in terms of inter-and intra-chain character. Finally, the exciton state is used to study the charge transfer from a polymer chain to an adjacent dopant molecule. From a variational wave function for the total system, we explore the dependence of the probability of charge transfer on the acceptor level, the hopping, and the wave function of the exciton. RP Yu, ZG (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Yu, Z/B-5547-2009; OI , Zhi-Gang/0000-0002-1376-9025 NR 60 TC 9 Z9 9 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3697 EP 3716 DI 10.1103/PhysRevB.56.3697 PG 20 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400043 ER PT J AU Stein, HJ Barbour, JC AF Stein, HJ Barbour, JC TI Unstable displacement defects and hydrogen trapping in GaAs SO PHYSICAL REVIEW B LA English DT Article ID H-IMPLANTED GAAS; SILICON; COMPLEX; PROTON; BONDS AB Defects produced by implantation of hydrogen into GaAs at 80 K have been investigated. Upon implantation, a predominant absorption band at 2029 cm(-1) for As-H centers is observed. A 10-cm(-1) full width at half maximum at 80 K for the band, and strong dependence of the frequency and bandwidth on measurement temperature, are indicative of bonding of hydrogen at displacement defects within the lattice. Results from annealing show loss of As-H centers between 180 and 250 K with an activation energy of 0.5+/-0.5 eV. Characteristics for As-H center annealing are compared to those reported previously for atomic displacement disorder in irradiated GaAs. Release of hydrogen from As-H bonds within thermally unstable damage regions is suggested to explain the annealing loss of As-H centers. An increase in absorption by Ga-H centers upon loss of As-H centers is attributed to retrapping of hydrogen on Ga neighbors of V-As or on V-As-As-i pair defects. RP SANDIA NATL LABS, POB 5800, ALBUQUERQUE, NM 87185 USA. RI Schaff, William/B-5839-2009 NR 33 TC 7 Z9 7 U1 0 U2 0 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 AUG 15 PY 1997 VL 56 IS 7 BP 3813 EP 3819 DI 10.1103/PhysRevB.56.3813 PG 7 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400053 ER PT J AU Artacho, E Yndurain, F Pajot, B Ramirez, R Herrero, CP Khirunenko, LI Itoh, KM Haller, EE AF Artacho, E Yndurain, F Pajot, B Ramirez, R Herrero, CP Khirunenko, LI Itoh, KM Haller, EE TI Interstitial oxygen in germanium and silicon SO PHYSICAL REVIEW B LA English DT Article ID INFRARED-ABSORPTION; ISOTOPIC DISORDER; BETHE-LATTICE; SPECTROSCOPY; VIBRATIONS; CRYSTALS; SI; GE AB The microscopic structure of interstitial oxygen in germanium and its associated dynamics are studied both experimentally and theoretically. The infrared absorption spectrum is calculated with a dynamical matrix model based on first-principles total-energy calculations describing the potential energy for the nuclear motions. Spectral features and isotope shifts are calculated and compared with available experimental results. From new spectroscopic data on natural and on quasimonoisotopic germanium samples, new isotope shifts have been obtained and compared with the theoretical predictions. The low-energy spectrum is analyzed in terms of a hindered rotor model. A fair understanding of the center is achieved, which is then compared with interstitial oxygen in silicon. The oxygen atom is nontrivially quantum delocalized both in silicon and in germanium, but the physics is shown to be very different: while the Si-O-Si quasimolecule is essentially linear, the Ge-O-Ge structure is puckered. The delocalization in a highly anharmonic potential well of oxygen in silicon is addressed using path-integral Monte Carlo simulations, for comparison with the oxygen rotation in germanium. The understanding achieved with this new information allows us to explain the striking differences between both systems, in both the infrared and the far-infrared spectral regions, and the prediction of the existence of hidden vibrational modes, never directly observed experimentally, but soundly supported by the isotope-shift analysis. C1 CIII UNIV AUTONOMA MADRID,DEPT FIS MAT CONDENSADA,MADRID 28049,SPAIN. UNIV DENIS DIDEROT,PHYS SOLIDES GRP,CNRS,UNITE ASSOCIEE,F-75251 PARIS 05,FRANCE. CSIC,INST CIENCIA MAT,E-28049 MADRID,SPAIN. NATL ACAD SCI UKRAINE,INST PHYS,UA-252650 KIEV 22,UKRAINE. KEIO UNIV,DEPT APPL PHYS & PHYSICOINFORMAT,KOHOKU KU,YOKOHAMA,KANAGAWA 223,JAPAN. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Artacho, E (reprint author), CIII UNIV AUTONOMA MADRID,INST NICOLAS CABRERA,MADRID 28049,SPAIN. RI yndurain, felix/J-2794-2014; Artacho, Emilio/G-2616-2015; Itoh, Kohei/C-5738-2014 OI Artacho, Emilio/0000-0001-9357-1547; NR 35 TC 49 Z9 49 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3820 EP 3833 DI 10.1103/PhysRevB.56.3820 PG 14 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400054 ER PT J AU Zuo, JK Wendelken, JF AF Zuo, JK Wendelken, JF TI Kinetic processes in the transition from Ag(111) crystallites to (root 3x root 3)R30 degrees domains for Ag/Si(111)-(7x7) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING TUNNELING MICROSCOPY; LOW-TEMPERATURE; ION-SCATTERING; MASS-TRANSPORT; SURFACE; AG; GROWTH; SI(111); NUCLEATION; INTERFACE AB Kinetic processes in the transition from metastable Ag(111) crystallites to (root 3X root 3)R30 degrees domains in the initial growth of Ag on the Si(111)-(7X7) surface have been investigated using spot profile analysis low-energy electron diffraction. Upon annealing above 468 K, the number density M(t) of metastable Ag(111) crystallites (deposited at T(d) similar to 333 K) is found to decrease exponentially with time t. Simultaneously, the average size of root 3 domains increases as R(t)similar to t(x), with the exponent x increasing with initially deposited coverage and limited to a range of 1/3 less than or equal to x less than or equal to 2/5. A theoretical model for this structural transition is established to explain these observations, which is based on a kinetic process driven by the step-edge line tension of terraces in the Ag(111) crystallites. Also, a dissociation energy of an atom from the step edge of a Ag(111)crystallite is determined to be E(dis)similar to 1.38 eV. C1 OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. RP Zuo, JK (reprint author), SW MISSOURI STATE UNIV, DEPT PHYS & ASTRON, SPRINGFIELD, MO 65804 USA. NR 31 TC 9 Z9 9 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 3897 EP 3902 DI 10.1103/PhysRevB.56.3897 PG 6 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400064 ER PT J AU Li, QM Zang, J Bishop, AR Soukoulis, CM AF Li, QM Zang, J Bishop, AR Soukoulis, CM TI Charge localization in disordered colossal-magnetoresistance manganites SO PHYSICAL REVIEW B LA English DT Article ID OFF-DIAGONAL DISORDER; TRANSPORT-PROPERTIES; POLARON FORMATION; SYSTEMS; LA1-XSRXMNO3; TRANSITION; STATES; FILMS; RESISTIVITY; MODEL AB The metallic or insulating nature of the paramagnetic phase of the colossal-magnetoresistance manganites is investigated via a double-exchange Hamiltonian with diagonal disorder. The mobility edge trajectory is determined with the transfer-matrix method. Density-of-states calculations indicate that random hopping alone is not sufficient to induce Anderson localization at the Fermi level with 20-30% doping. We argue that the metal-insulator transition is likely due to the formation of localized polarons from nonuniform extended states as the effective bandwidth is reduced by random hoppings and electron-electron interactions. C1 IOWA STATE UNIV, DEPT PHYS & ASTRON, AMES, IA 50011 USA. LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. LOS ALAMOS NATL LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. RP US DOE, AMES LAB, AMES, IA 50011 USA. RI Soukoulis, Costas/A-5295-2008 NR 48 TC 66 Z9 66 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 AUG 15 PY 1997 VL 56 IS 8 BP 4541 EP 4544 DI 10.1103/PhysRevB.56.4541 PG 4 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700044 ER PT J AU Wang, X deGroot, FMF Cramer, SP AF Wang, X deGroot, FMF Cramer, SP TI Spin-polarized x-ray emission of 3d transition-metal ions: A comparison via K alpha and K beta detection SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION-SPECTROSCOPY; BRANCHING RATIO; MULTIPLET STRUCTURE; NICKEL COMPOUNDS; SPECTRA; FLUORESCENCE; SCATTERING; DICHROISM; STATE; MNF2 AB This paper demonstrates that spin-polarized x-ray-excitation spectra can be obtained using K alpha emission as well as K beta lines. A spin-polarized analysis of K alpha x-ray emission and the excitation spectra by K alpha detection on a Ni compound is reported. A systematic analysis of the first-row transition-metal ions using the ligand-field multiplet calculation is presented for K alpha and K beta emission spectra. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV GRONINGEN,NL-9747 AG GRONINGEN,NETHERLANDS. RP Wang, X (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616, USA. RI de Groot, Frank/A-1918-2009 NR 45 TC 79 Z9 79 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4553 EP 4564 DI 10.1103/PhysRevB.56.4553 PG 12 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700046 ER PT J AU Vacar, D Maniloff, ES McBranch, DW Heeger, AJ AF Vacar, D Maniloff, ES McBranch, DW Heeger, AJ TI Charge-transfer range for photoexcitations in conjugated polymer/fullerene bilayers and blends SO PHYSICAL REVIEW B LA English DT Article ID PHOTOINDUCED ELECTRON-TRANSFER; POLY(P-PHENYLENEVINYLENE); POLYMERS; SINGLET; FILMS; PHOTOLUMINESCENCE; TRANSPORT; STATES; C-60 AB Time-resolved photoinduced absorption was measured on bilayers of poly-[2-methoxy,5-(2'-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV) and fullerene (C-60), and on MEH-PPV/C-60 composite films of various concentrations. We find that even in the picosecond regime, charge transfer from the conjugated polymer to C-60 slows down the decay dynamics relative to the decay in the pure samples. The fact that charge transfer occurs in the picosecond time scale in bilayer structure (thickness approximate to 200 Angstrom) implies that diffusion of localized excitations to the interface is not the dominant mechanism; the charge-transfer range is a significant fraction of the film thickness. From an analysis of the excited-stare decay curves, we estimate the charge-transfer range to be 80 Angstrom and interpret that range as resulting from quantum delocalization of the photoexcitations. C1 LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,LOS ALAMOS,NM 87545. RP Vacar, D (reprint author), UNIV CALIF SANTA BARBARA,INST POLYMERS & ORGAN SOLIDS,SANTA BARBARA,CA 93106, USA. NR 25 TC 77 Z9 77 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4573 EP 4577 DI 10.1103/PhysRevB.56.4573 PG 5 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700048 ER PT J AU Nusse, S Bolivar, PH Kurz, H Klimov, V Levy, F AF Nusse, S Bolivar, PH Kurz, H Klimov, V Levy, F TI Carrier cooling and exciton formation in GaSe SO PHYSICAL REVIEW B LA English DT Article ID GAAS QUANTUM-WELLS; GALLIUM SELENIDE; LUMINESCENCE SPECTRA; SPECTROSCOPY; RELAXATION; DYNAMICS; SUPERLATTICE; INSE AB The initial cooling of hot carriers and the subsequent exciton formation in GaSe are studied by time-resolved photoluminescence (PL) using femtosecond up-conversion techniques. From the time-resolved PL spectra of this layered III-VI semiconductor two different energy relaxation channels are derived. After an initial subpicosecond cooling due to Frohlich-type interaction of carriers with longitudinal optical E'(2(2)) phonons a slower regime follows. which is dominated by deformation potential interaction with the nonpolar optical A(1)'(1(2)) phonons. The coupling constant for nonpolar optical phonon scattering is derived. The subsequent formation of excitons is studied at different carrier densities and detection energies. A cross section for the free-exciton formation is determined based on a rate equation model. C1 LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,LOS ALAMOS,NM 87545. ECOLE POLYTECH FED LAUSANNE,INST PHYS APPL,CH-1015 LAUSANNE,SWITZERLAND. RP Nusse, S (reprint author), RHEIN WESTFAL TH AACHEN,INST HALBLEITERTECH 2,SOMMERFELDSTR 24,D-52056 AACHEN,GERMANY. RI Haring Bolivar, Peter/C-9436-2012 OI Haring Bolivar, Peter/0000-0001-5875-556X NR 35 TC 28 Z9 28 U1 3 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4578 EP 4583 DI 10.1103/PhysRevB.56.4578 PG 6 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700049 ER PT J AU Dixon, DC Wald, KR McEuen, PL Melloch, MR AF Dixon, DC Wald, KR McEuen, PL Melloch, MR TI Dynamic nuclear polarization at the edge of a two-dimensional electron gas SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM HALL REGIME; OPTICALLY PUMPED NMR; MAGNETIC-RESONANCE; STATE SCATTERING; GALLIUM-ARSENIDE; CHANNELS; INTEGER; SKYRMIONS; TRANSPORT; WELLS AB We have used gated GaAs/AlxGa1-xAs heterostructures to explore nonlinear transport between spin-resolved Landau level edge states over a submicrometer region of two-dimensional electron gas (2DEG). The current I flowing from one edge state to the other as a function of the voltage V between them shows diodelike behavior-a rapid increase in I above a well-defined threshold V, under forward bias, and a slower increase in I under reverse bias. In these measurements, a pronounced influence of a current-induced nuclear-spin polarization on the spin splitting is observed, and supported by a series of NMR experiments. We conclude that the hyperfine interaction plays an important role in determining the electronic properties at the edge of a 2DEG. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV SCI MAT,BERKELEY,CA 94720. PURDUE UNIV,SCH ELECT & COMP ENGN,W LAFAYETTE,IN 47907. RP Dixon, DC (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 39 TC 97 Z9 97 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4743 EP 4750 DI 10.1103/PhysRevB.56.4743 PG 8 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700072 ER PT J AU Kralik, B Rappe, AM Louie, SG AF Kralik, B Rappe, AM Louie, SG TI Variational Monte Carlo calculation of the spin gap in the nu=1 quantum Hall liquid SO PHYSICAL REVIEW B LA English DT Article ID 2-DIMENSIONAL ELECTRON-GAS; MAGNETIC-FIELDS; WAVE-FUNCTIONS; LANDAU-LEVEL; EXCITATIONS; FERMION; SYSTEMS AB A variational method of calculating the spin 1 excitation energies of the v=1 quantum Wall liquid is presented in detail. We are able to include Landau-level mixing and finite-thickness effects. The many-body wave functions of the states near v=1 filling are taken to be a product of a lowest-Landau-level Laughlin-type wave function and a Jastrow factor. A significant reduction in the calculated spin gap is found due both to Landau-level mixing (similar to 40% at r(s)=1) and to the effect of the finite thickness of the liquid (a further similar to 30% at r(s)=1). We find our calculations to be consistent with recent photoluminescence experiments in delta-doped samples. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Kralik, B (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 26 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4760 EP 4771 DI 10.1103/PhysRevB.56.4760 PG 12 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700074 ER PT J AU Sieger, MT Simpson, WC Orlando, TM AF Sieger, MT Simpson, WC Orlando, TM TI Electron-stimulated desorption of D+ from D2O ice: Surface structure and electronic excitations SO PHYSICAL REVIEW B LA English DT Article ID AMORPHOUS WATER ICE; VAPOR-DEPOSITED ICE; X-RAY-SCATTERING; GLASS-TRANSITION; MOLECULAR-HYDROGEN; ASTROPHYSICAL IMPLICATIONS; ENERGY-DISTRIBUTION; REFRACTIVE-INDEX; CRYSTALLINE ICE; SOLID WATER AB We present a study of the electron-stimulated desorption of deuterium cations (D+) from thin (1-40 ML) D2O ice films vapor deposited on a Pt(111) substrate. Measurements of the total yield and velocity distributions as a function of temperature from 90 to 200 K show that the D+ yield changes with film thickness, surface temperature, and ice phase. We observe two energy thresholds for cation emission, near 25 and 40 eV, which are weakly dependent upon the ice temperature and phase. The cation time-of-flight (TOF) distribution is at least bimodal, indicating multiple desorption channels. A decomposition of the TOF distributions into ''fast'' and ''slow'' channels shows structure as a function of excitation energy, him thickness, and temperature. The D+ yield generally increases with temperature, rising near 120 K on amorphous ice, and near 135 K on crystalline ice. The amorphous-crystalline phase transition at similar to 160 K causes a drop in total desorption yield. The temperature dependence of D- desorption via the B-2(1) dissociative electron attachment resonance is very similar to the slow D+ yield, and likely involves similar restructuring and lifetime effects. The data collectively suggest that a thermally activated reduction of surface hydrogen bonding increases the lifetime of the excited states responsible for ion desorption, and that these lifetime effects are strongest for excited states involving a(1) bands. RP Sieger, MT (reprint author), PACIFIC NW LAB, ENVIRONM MOL SCI LAB, POB 999, MSIN K-14, RICHLAND, WA 99352 USA. RI Sieger, Matthew/B-4261-2011 OI Sieger, Matthew/0000-0001-7387-3660 NR 86 TC 46 Z9 46 U1 4 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP 4925 EP 4937 DI 10.1103/PhysRevB.56.4925 PG 13 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700096 ER PT J AU Choi, IH Yu, PY AF Choi, IH Yu, PY TI Observation of metastable deep acceptor states in AgGaS2 from donor-acceptor pair-emission spectra SO PHYSICAL REVIEW B LA English DT Article ID CHALCOPYRITE SEMICONDUCTORS; CENTERS AB We report the discovery of photoinduced quenching of donor-acceptor pair-emission peaks in AgGaS2 crystals at liquid-He temperatures. From previous high-pressure studies [Phys. Rev. B 55, 9642 (1997)] these peaks have been attributed to radiative recombination between shallow donors and deep acceptors. We explain our results by the optical capture of the deep neutral accepters into optically inactive metastable states. At low temperatures the capture time is found to be less than or equal to 10(2) s while the emission time is of the order of 10(3) s. The thermal capture barrier height of the metastable states is determined to be about 2 meV. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Choi, IH (reprint author), CHUNG ANG UNIV,DEPT PHYS,SEOUL 156756,SOUTH KOREA. NR 11 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP R4321 EP R4324 PG 4 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700007 ER PT J AU Leon, R Williams, DRM Krueger, J Weber, ER Melloch, MR AF Leon, R Williams, DRM Krueger, J Weber, ER Melloch, MR TI Diffusivity transients and radiative recombination in intermixed In0.5Ga0.5As/GaAs quantum structures SO PHYSICAL REVIEW B LA English DT Article ID WELL STRUCTURES; INTERDIFFUSION; INGAAS/GAAS; HETEROSTRUCTURES; PHOTOLUMINESCENCE; DYNAMICS; STRAIN AB The effects of thermally induced compositional disordering on the luminescence from two-dimensional and zero-dimensional In0.5Ga0.5As/GaAs structures an examined. Quantum-mechanical numerical calculations modeling changes in the quantum-well (QW) confining potential with interdiffusion have been used to obtain values for diffusivities. These show transient behavior. Activation energies for interdiffusion (3.5+/-0.3 eV) are found to be similar to values reported for low-indium-content InxGa1-xAs/GaAs QW's. In quantum-dot structures, larger blueshifts can be obtained than in QW's under similar conditions. Interdiffusion decreased activation energies for radiative recombination, reflecting changes in confining potentials, and affecting lifetime ratios in recombination processes. The latter were observed in all intermixed heterostructures regardless of dimensionality. C1 AUSTRALIAN NATL UNIV,INST ADV STUDIES,RES SCH PHYS SCI,DEPT MATH APPL,CANBERRA,ACT 0200,AUSTRALIA. ERNEST ORLANDO LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. PURDUE UNIV,SCH ELECT & COMP ENGN,W LAFAYETTE,IN 47907. RP Leon, R (reprint author), AUSTRALIAN NATL UNIV,INST ADV STUDIES,RES SCH PHYS SCI,DEPT ELECT MAT ENGN,CANBERRA,ACT 0200,AUSTRALIA. NR 19 TC 44 Z9 44 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP R4336 EP R4339 PG 4 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700011 ER PT J AU Li, QM Katsoprinakis, S Economou, EN Soukoulis, CM AF Li, QM Katsoprinakis, S Economou, EN Soukoulis, CM TI Scaling properties in highly anisotropic systems SO PHYSICAL REVIEW B LA English DT Article ID DISORDERED ELECTRONIC SYSTEMS; ANDERSON LOCALIZATION; CONDUCTANCE; MODEL; MEDIA AB Scaling of the conductances and the finite-size localization lengths is generalized to anisotropic systems and tested in two-dimensional systems. Scaling functions of isotropic systems are recovered once the dimension of the system in each direction is chosen to be proportional to the localization length. It is also shown that the geometric mean of the localization lengths is a function of the geometric mean of the conductivities. The ratio of the localization lengths is proportional to the square root of the ratio of the conductivities, which in turn is proportional to the anisotropy strength t, in the weak scattering limit. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. UNIV CRETE,RES CTR CRETE,IRAKLION 71110,CRETE,GREECE. UNIV CRETE,DEPT PHYS,IRAKLION 71110,CRETE,GREECE. RP Li, QM (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Economou, Eleftherios /E-6374-2010; Soukoulis, Costas/A-5295-2008 NR 23 TC 11 Z9 11 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP R4297 EP R4300 PG 4 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700001 ER PT J AU Mielke, CH Harrison, N Rickel, DG Lacerda, AH Vestal, RM Montgomery, LK AF Mielke, CH Harrison, N Rickel, DG Lacerda, AH Vestal, RM Montgomery, LK TI Fermi-surface topology of kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br at ambient pressure SO PHYSICAL REVIEW B LA English DT Article ID ORGANIC SUPERCONDUCTOR KAPPA-(BEDT-TTF)(2)CUBR; C-13 NMR; BEDT-TTF; KAPPA-(ET)(2)CUBR; RELAXATION; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; KAPPA-(BEDT-TTF)2CUBR; OSCILLATIONS; TRANSITION; STATE AB Ambient pressure Fermi-surface measurements are reported for kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br. The single Shubnikov-de Haas frequency that is detected (3798+/-5 T) corresponds to 100% of the Brillouin zone and can be attributed to the beta orbit that results from magnetic breakdown. From the temperature dependence of the oscillations, it appears that kappa-(BEDT-TTF)(2)Cu[N(CN)(2))Br possesses a conventional Fermi-liquid ground state, although with a short mean free path, possibly due to the presence of Cu(II) ions. The effective mass as determined from the beta-orbit oscillations is m* = 5.4 +/- 0.1 m(e). C1 INDIANA UNIV,DEPT CHEM,BLOOMINGTON,IN 47405. RP Mielke, CH (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 34 TC 46 Z9 46 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 8 BP R4309 EP R4312 PG 4 WC Physics, Condensed Matter SC Physics GA XV007 UT WOS:A1997XV00700004 ER PT J AU Sikivie, P Tkachev, II Wang, Y AF Sikivie, P Tkachev, II Wang, Y TI Secondary infall model of galactic halo formation and the spectrum of cold dark matter particles on Earth SO PHYSICAL REVIEW D LA English DT Article ID AXION MINICLUSTERS; CP CONSERVATION; INVISIBLE-AXION; COSMIC AXIONS; GALAXIES; EVOLUTION; UNIVERSE; CLUSTERS; ROTATION; SEARCH AB The spectrum of cold dark matter particles on Earth is expected to have peaks in velocity space associated with particles which are falling onto the Galaxy for the first time and with particles which have fallen in and out of the Galaxy only a small number of times in the past. We obtain estimates for the velocity magnitudes and the local densities of the particles in these peaks. To this end we use the secondary infall model of galactic halo formation which we have generalized to take account of the angular momentum of the dark matter particles. The new model is still spherically symmetric and it admits self-similar solutions. In the absence of angular momentum, the model produces flat rotation curves for a large range of values of a parameter epsilon which is related to the spectrum of primordial density perturbations. We find that the presence of angular momentum produces an effective core radius; i.e., it makes the contribution of the halo to the rotation curve go to zero at zero radius. The model provides a detailed description of the large scale properties of galactic halos including their density profiles, their extent, and total mass. We obtain predictions for the kinetic energies of the particles in the velocity peaks and estimates for their local densities as functions of the amount of angular momentum, the age of the Universe, and epsilon. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. RUSSIAN ACAD SCI,INST NUCL RES,MOSCOW 117312,RUSSIA. NASA,FERMILAB ASTROPHYS CTR,FERMILAB,BATAVIA,IL 60510. RP Sikivie, P (reprint author), UNIV FLORIDA,DEPT PHYS,GAINESVILLE,FL 32611, USA. RI Wang, Yun/B-5724-2011 OI Wang, Yun/0000-0002-4749-2984 NR 44 TC 132 Z9 132 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 AUG 15 PY 1997 VL 56 IS 4 BP 1863 EP 1878 DI 10.1103/PhysRevD.56.1863 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT856 UT WOS:A1997XT85600006 ER PT J AU Kinney, WH AF Kinney, WH TI Hamilton-Jacobi approach to non-slow-roll inflation SO PHYSICAL REVIEW D LA English DT Article ID COSMOLOGICAL PERTURBATIONS; DENSITY PERTURBATIONS; UNIVERSE SCENARIO; SYMMETRY-BREAKING; HYBRID INFLATION; SCALAR FIELD; FLUCTUATIONS; FLATNESS; DYNAMICS; HORIZON AB I describe a general approach to characterizing cosmological inflation outside the standard slow-roll approximation, based on the Hamilton-Jacobi formulation of scalar field dynamics. The basic idea is to view the equation of state of the scalar held matter as the fundamental dynamical variable, as apposed to the field value or the expansion rate. I discuss how to formulate the equations of motion for scalar and tensor fluctuations in situations where the assumption of slow roll is not valid. I apply the general results to the simple case uf inflation from an ''inverted'' polynomial potential, and to the more complicated case of hybrid inflation. RP Kinney, WH (reprint author), NASA,FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 30 TC 61 Z9 61 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 AUG 15 PY 1997 VL 56 IS 4 BP 2002 EP 2009 DI 10.1103/PhysRevD.56.2002 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT856 UT WOS:A1997XT85600017 ER PT J AU Worah, MP AF Worah, MP TI Supersymmetric baryogenesis at the electroweak phase transition SO PHYSICAL REVIEW D LA English DT Article ID STANDARD MODEL; BARYON ASYMMETRY; UNIVERSE; TEMPERATURE; CONSTRAINTS; MATRIX; MSSM AB We study the possibility of baryogenesis in the case of supersymmetry breaking with largre mixing between the (c) over tilde(R) and (t) over tilde(R) or (u) over tilde(R) and (t) over tilde(R) squarks resulting in one light right-handed up-type squark mass eigenstate. We argue that in this case the electroweak phase transition will be first order, and that large phases already present in the quark mass matrices can generate a baryon asymmetry of the correct magnitude without introducing any new phases specifically for this purpose. We study in detail a particular ansatz for supersymmetry breaking and CP violation where there is only one CP violating phase in the theory: in the up-type quark mass matrix. We study the constraints placed on this model by baryogenesis and flavor physics. This scenario has robust implications for low energy flavor physics including D-0-(D) over bar(0) mixing and an electric dipole moment for the neutron that are close to the experimental bounds, and CP violation in the B-(B) over bar system that is different from that in the standard model. RP STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94305 USA. NR 32 TC 18 Z9 18 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD AUG 15 PY 1997 VL 56 IS 4 BP 2010 EP 2018 DI 10.1103/PhysRevD.56.2010 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT856 UT WOS:A1997XT85600018 ER PT J AU Keil, W Janka, HT Schramm, DN Sigl, G Turner, MS Ellis, J AF Keil, W Janka, HT Schramm, DN Sigl, G Turner, MS Ellis, J TI Fresh look at axions and SN 1987A SO PHYSICAL REVIEW D LA English DT Article ID NUCLEON SPIN FLUCTUATIONS; NEUTRON-STARS; CP CONSERVATION; INVISIBLE AXION; SUPERNOVA CORES; DIRAC NEUTRINOS; HARMLESS AXION; SN-1987A; CONSTRAINTS; SN1987A AB We reexamine the very stringent limit on the axion mass based on the strength and duration of the neutrino signal from SN 1987A, in the light of new measurements of the axial-vector coupling strength of nucleons, possible suppression of axion emission due to many-body effects, and additional emission processes involving pions. The suppression of axion emission due to nucleon spin fluctuations induced by many-body effects degrades previous limits by a factor of about 2. Emission processes involving thermal pions can strengthen the limits by a factor of 3-4 within a perturbative treatment that neglects saturation of nucleon spin fluctuations. Inclusion of saturation effects, however, tends to make the limits less dependent on pion abundances. The resulting upper limit to the axion mass also depends on the precise couplings of the axion and ranges from 0.5 x 10(-3) eV to 6 x 10(-3) eV, consistent with previous results. C1 UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60510 USA. RP MAX PLANCK INST ASTROPHYS, KARL SCHWARZCHILD STR 1, D-85740 GARCHING, GERMANY. NR 55 TC 58 Z9 58 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD AUG 15 PY 1997 VL 56 IS 4 BP 2419 EP 2432 DI 10.1103/PhysRevD.56.2419 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT856 UT WOS:A1997XT85600065 ER PT J AU Linde, A Riotto, A AF Linde, A Riotto, A TI Hybrid inflation in supergravity SO PHYSICAL REVIEW D LA English DT Article AB We propose a simple realization of hybrid inflation in supergravity. Inflation in this scenario is relatively short, and inflationary density perturbations fall down on large scales, which corresponds to a blue spectrum with n>1. Superheavy strings which are formed after inflation in this scenario produce density perturbations of comparable magnitude. In this mixed perturbation (MP) model one may have microwave anisotropy produced by strings and galaxy formation due to inflationary perturbations. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP Linde, A (reprint author), STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305, USA. NR 15 TC 235 Z9 235 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 AUG 15 PY 1997 VL 56 IS 4 BP R1841 EP R1844 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT856 UT WOS:A1997XT85600003 ER PT J AU Caldwell, WA Nguyen, JH Pfrommer, BG Mauri, F Louie, SG Jeanloz, R AF Caldwell, WA Nguyen, JH Pfrommer, BG Mauri, F Louie, SG Jeanloz, R TI Structure, bonding, and geochemistry of xenon at high pressures SO SCIENCE LA English DT Article ID X-RAY-DIFFRACTION; SOLID XENON; STATE; METALLIZATION; TRANSITIONS; EQUATION; ORIGIN; MANTLE; GASES; MBAR AB Although xenon becomes metallic at pressures above about 100 gigapascals, a combination of quantum mechanical calculations and high pressure-temperature experiments reveals no tendency on the part of xenon to form a metal alloy with iron or platinum to at least 100 to 150 gigapascals. The transformation of xenon from face-centered cubic (fee) to hexagonal close-packed (hop) structures is kinetically hindered, the differences in volume and bulk modulus between the two phases being smaller than we can resolve (less than 0.3 percent and 0.6 gigapascals, respectively). The equilibrium fcc-hcp phase boundary is at 21 (+/-3) gigapascals, which is a lower pressure than was previously thought, and it is unlikely that Earth's core serves as a reservoir for primordial xenon. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Caldwell, WA (reprint author), UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720, USA. RI mauri, francesco/K-5726-2012 OI mauri, francesco/0000-0002-6666-4710 NR 38 TC 72 Z9 74 U1 1 U2 19 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD AUG 15 PY 1997 VL 277 IS 5328 BP 930 EP 933 DI 10.1126/science.277.5328.930 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ985 UT WOS:A1997XQ98500034 ER PT J AU Liberman, V Malba, V Bernhart, AF AF Liberman, V Malba, V Bernhart, AF TI Vapor deposition of polyimide: segregation of partially reacted species at the polyimide Si (100) interface SO THIN SOLID FILMS LA English DT Article DE deposition process; Fourier transform infrared spectroscopy; adhesion; polymers AB We examined the vapor deposition of polyimide produced by co-evaporation of pyromellitic dianhydride and oxydianiline. Using internal reflectance spectroscopy and prism coupling techniques, we monitored the effects of varying relative monomer fluxes on cured film stoichiometry. We observed the effects of monomer interdiffusion during the ex-situ curing leading to segregation of partially reacted species at the film/substrate interface. Such interface segregation may be influential in determining adhesion of polyimide to metal layers for microelectronics applications. (C) 1997 Elsevier Science S.A. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 10 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD AUG 15 PY 1997 VL 305 IS 1-2 BP 26 EP 29 DI 10.1016/S0040-6090(97)00117-X PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA XX864 UT WOS:A1997XX86400003 ER PT J AU Xu, X Cesarano, J Burch, E Lopez, GP AF Xu, X Cesarano, J Burch, E Lopez, GP TI Template-assisted electrochemical deposition of ultrathin films of cadmium sulfide SO THIN SOLID FILMS LA English DT Article DE electrochemistry; cadmium sulphide; deposition process; Langmuir-Blodgett films ID LANGMUIR-BLODGETT-FILMS; SEMICONDUCTOR-FILMS; NUCLEATION; SURFACES; GROWTH AB Uniform thin films of cadmium sulfide were prepared by template-assisted electrochemical deposition on gold electrodes covered with Langmuir-Blodgett (LB) films. An electrolytic cell was used for the production of low concentrations of S- to effect heterogeneous crystallization on LB films, while preventing homogeneous precipitation, 3-, 4- and 5-layer LB films of cadmium arachidate were investigated. Characterization of deposited films by optical microscopy, atomic force microscopy and energy dispersive X-ray analysis of film composition indicated that a variety of different types of CdS films can be produced depending on the type of LB film used, the electrode at which template-assisted deposition is carried out, the magnitude and frequency of alternating potentials used, and the deposition time used. In general, hydrophilic organic films that present cadmium carboxylate groups to the deposition surface (i.e. 3- and 5-layer LB films) supported crystallization of CdS, while those that present hydrophobic, methyl groups (i.e. 4-layer LB films and self-assembled monolayers of alkanethiolates on gold) did not. The best methods for the rapid deposition of conformal, ultrathin films (< 100 nm) of CdS used highly-ordered 5-layer LB films at grounded electrodes. The data presented suggest that templating with LB films, when used together with electrochemical deposition, has potential for the convenient production of oriented crystalline thin films of cadmium sulfide and similar materials. (C) 1997 Elsevier Science S.A. C1 SANDIA NATL LABS,DIV 1841,ALBUQUERQUE,NM 87106. UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. NR 18 TC 5 Z9 9 U1 2 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD AUG 15 PY 1997 VL 305 IS 1-2 BP 95 EP 102 DI 10.1016/S0040-6090(96)09520-X PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA XX864 UT WOS:A1997XX86400013 ER PT J AU Tam, CN Bour, P Eckert, J Trouw, FR AF Tam, CN Bour, P Eckert, J Trouw, FR TI Inelastic neutron scattering study of hydrogen-bonded solid formamide at 15 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PROTEIN SECONDARY STRUCTURE; FORCE-FIELD; VIBRATIONAL-SPECTRA; N-METHYLACETAMIDE; DYNAMICS; AMIDES; SPECTROSCOPY; PEPTIDES; GUANINE AB The inelastic neutron scattering spectra for formamide (HCONH2) and its N-deuterated isomer (HCOND2) have been measured. The spectra are interpreted on the basis of a vibrational harmonic normal-mode analysis using a variety of models. The models are a single molecule, a formamide dimer, a tetramer resembling the unit cell of crystalline formamide, and a cluster of 36 formamide molecules. Force fields of the first three model systems were computed ab initio using the B3LYP DFT functional and the 6-31G** basis set. The tetramer force field was then applied to the cluster of 36 molecules. Most of the observed vibrational bands could be assigned by comparing the relative INS intensities and frequencies calculated for the theoretical models with the measured spectra. Reasonable agreement between the calculation and the experiment was achieved on this basis. The results confirm the presence of the strong hydrogen bonding in the formamide lattice. However, the previously proposed model for the hydrogen bonding in N-methylacetamide involving a dynamical proton exchange between the amidic (... OCNH ....) and imidolic (... HOCN ...) forms is not consistent with our findings. C1 ACAD SCI CZECH REPUBL,INST ORGAN CHEM & BIOCHEM,CR-16610 PRAGUE,CZECH REPUBLIC. LOS ALAMOS NATL LAB,LANSCE,LOS ALAMOS,NM 87545. RP Tam, CN (reprint author), ARGONNE NATL LAB,DIV INTENSE PULSED NEUTRON SOURCE,BLDG 360,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Lujan Center, LANL/G-4896-2012; Bour, Petr/G-5561-2014 NR 37 TC 25 Z9 25 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 14 PY 1997 VL 101 IS 33 BP 5877 EP 5884 DI 10.1021/jp970122m PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XR348 UT WOS:A1997XR34800007 ER PT J AU Cremer, PS Su, XC Shen, YR Somorjai, GA AF Cremer, PS Su, XC Shen, YR Somorjai, GA TI Temperature-dependent rearrangements and reactions of acetylene adsorbed on Pt(111) monitored in the range 125-381 K by sum frequency generation SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID C-2 HYDROCARBON FRAGMENTS; METAL-SURFACES; ETHYLIDYNE; ETHYLENE; CONVERSION; VINYL AB The thermally induced rearrangements and reactions of acetylene on the (111) crystal face of platinum were observed by monitoring the vibrational spectra of surface adsorbates in the CH stretch range with infrared-visible sum frequency generation. It was found that adsorption of acetylene at 125 K led directly to the formation of an adsorbed vinylidene species (eta(2)-mu(3)-CCH2). Upon annealing, a variety of different species were formed that included ethylidene (M=CHCH3), di-sigma-bonded ethylene (M-CH2CH2-M), mu-vinylidene (M=CCH2), and ethylidyne (M=CCH3). The presence of species with C2H4 and C2H3 stoichiometry was strong evidence that a disproportionation reaction must occur. Above 381 K ethylidyne was the only observable species on the surface. C1 UNIV CALIF BERKELEY,DEPT CHEM & PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 12 TC 56 Z9 56 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 14 PY 1997 VL 101 IS 33 BP 6474 EP 6478 DI 10.1021/jp9705380 PG 5 WC Chemistry, Physical SC Chemistry GA XR347 UT WOS:A1997XR34700023 ER PT J AU Gruszkiewicz, MS Wood, RH AF Gruszkiewicz, MS Wood, RH TI Conductance of dilute LiCl, NaCl, NaBr, and CsBr solutions in supercritical water using a flow conductance cell SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID APPARENT MOLAR VOLUMES; SODIUM-CHLORIDE SOLUTIONS; 1-1 ELECTROLYTE-SOLUTIONS; CRITICAL-TEMPERATURE; AQUEOUS-ELECTROLYTES; INFINITE DILUTION; 0.0025 MOL.KG-1; 3.0 MOL.KG-1; 38.0 MPA; DENSITIES AB Conductivities of LiCl(aq), NaCl(aq), NaBr(aq), and CsBr(aq) solutions have been measured in the range of concentrations from 0.013 to 4 x 10(-8) mol.dm(-3) using a flow conductance cell at temperatures between 603 K and 674 K and pressures between 15 MPa and 28 MPa (water densities from 650 to 200 kg.m(-3)). Limiting equivalent conductances and ionization equilibrium constants calculated from the concentration dependence of the equivalent conductance are reported. Previous measurements of equilibrium constants in the low-density supercritical region, although of lesser accuracy, agree well with the present results. Even at the critical density and 2.5 K above the critical temperature there is no evidence for the critical effects which make the Debye-Huckel limiting law invalid at the critical isotherm-isobar. No critical scaling of ho is observed. Walden's rule is not obeyed and the Stokes radius increases by 70% near the critical region as the density goes from 700 to 200 kg.m(-3), suggesting an increase in the number of water molecules carried along with the ion. The differences in mobility between different ions are rather small when compared to the differences in crystallographic ionic radii. The association constants are in the order CsBr < NaBr < NaCl approximate to LiCl. C1 UNIV DELAWARE,DEPT CHEM & BIOCHEM,NEWARK,DE 19716. UNIV DELAWARE,CTR MOL & ENGN THERMODYNAM,NEWARK,DE 19716. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. RI Gruszkiewicz, Miroslaw/L-2389-2016 OI Gruszkiewicz, Miroslaw/0000-0002-6551-6724 NR 41 TC 54 Z9 55 U1 4 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 14 PY 1997 VL 101 IS 33 BP 6549 EP 6559 DI 10.1021/jp970197q PG 11 WC Chemistry, Physical SC Chemistry GA XR347 UT WOS:A1997XR34700034 ER PT J AU Baes, CF Moyer, BA AF Baes, CF Moyer, BA TI Solubility parameters and the distribution of ions to nonaqueous solvents SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SOLVATION ENERGY RELATIONSHIPS; LAYER CONTINUUM MODEL; GIBBS FREE-ENERGY; COMPLEX-FORMATION; ENTHALPIES; EXTRACTION; HYDRATION; EQUATION; SOFTNESS AB Provided a singly charged, spherically symmetrical ion has a radius greater than ca. 0.2 nm, its distribution to a nonaqueous solvent from water can be accounted for by assigning to it a Hildebrand solubility parameter estimated for an uncharged atom or molecule, regardless of the model assumed for the Gibbs energy of charging the ion-that of Born, Abraham, and Liszi (J. Chem. Soc., Faraday Trans. 1 1978, 74, 1604, 2858) or Abe (J. Phys. Chem. 1986, 90, 713)-in the nonaqueous phase. For smaller ions, however, no choice of solubility parameter or ion size can alone account for their extractability. The extensive data available for the Gibbs energy of transfer of monovalent ions from water to a variety of solvents can be accounted for by assigning to the ion, in addition to a plausible solubility parameter, an effective radius r(s) = (r(i)(3) + Delta r(s)(3))(1/3), wherein r(i) is the radius of the ion and Delta r(s) is an adjustable distance characteristic of the solvent. Separate sets of Delta r(s) values are needed for cations and anions. While the alternative models for charging the ion all give acceptable fits to the data, the shell model of Abraham and Liszi was selected as the most appropriate. The distance Delta r(s) can be predicted for cations from the molar volume of the solvent and its hydrogen-bond acceptance index beta. For anions, Delta r(s) can be predicted from the molar volume and the hydrogen-bond donation index alpha. On the basis of these correlations, expressions are derived for predicting the extractability of a singly charged, approximately spherical ion and its activity coefficient in the nonaqueous phase. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. RI Solominow, Sonia/A-4021-2008; Moyer, Bruce/L-2744-2016 OI Moyer, Bruce/0000-0001-7484-6277 NR 27 TC 15 Z9 15 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 14 PY 1997 VL 101 IS 33 BP 6566 EP 6574 PG 9 WC Chemistry, Physical SC Chemistry GA XR347 UT WOS:A1997XR34700036 ER PT J AU Tang, JZ Burgdorfer, J AF Tang, JZ Burgdorfer, J TI Excitation-ionization by photoabsorption at low and intermediate energies SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID PHOTOIONIZATION CROSS-SECTIONS; HELIUM; PHOTON; SATELLITES; THRESHOLD; HE AB We present first results for excitation-ionization of helium satellite lines He+(nl) above the double-ionization threshold using the hyperspherical close-coupling (HSCC) method. The ratio for excitation of the satellite line to the main line (i.e. n = 1) is calculated over a wide range of energies from near the double-ionization threshold (E-ph = 80 eV) to energies (E-ph similar to 1 keV) above which perturbation methods are expected to be more suitable. Comparison with very recent experiments of Wehlitz et al shows excellent agreement for ail satellite lines of n = 2, 3, 4 as well as for the angular distribution asymmetry parameter beta. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Tang, JZ (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 25 TC 12 Z9 12 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD AUG 14 PY 1997 VL 30 IS 15 BP L523 EP L529 DI 10.1088/0953-4075/30/15/003 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XR707 UT WOS:A1997XR70700003 ER PT J AU Huang, BQ Corbett, JD AF Huang, BQ Corbett, JD TI Intermetallic hydrides as zintl phases: A(3)TtH(2) compounds (A=Ca, Yb; Tt=Sn, Ph) and their structural relationship to the corresponding oxides SO INORGANIC CHEMISTRY LA English DT Article AB Shiny crystals of the isotypic title compounds are obtained in high yield from suitable proportions of AH(2), metal A, and Sn or Pb in welded Ta containers slowly cooled from 1100 degrees C, These were characterized by single-crystal X-ray diffraction for Ca3SnH2 and Ca3PbH2 (orthorhombic, Cmcm (No. 63), Z = 4, a = 8.866(1), 8.937(1) Angstrom, b = 11.371(2), 11.470(2) Angstrom, c = 5.220(1), 5.2551(7) Angstrom, respectively). The structure contains distorted hcp layers of Ca(3)Tt between which hydrogen occupies all tetrahedral voids formed by Ca atoms. These tetrahedra share three edges to form double chains along the c axis that are separated by Tt atoms, Both calcium compounds are diamagnetic semiconductors, and the family can all be formulated in terms of oxidation states as Zintl phases (A(+2))(3)Tt(-4)(H-)(2). Their structure may be derived from the hexagonal version of the cubic perovskitic Ca3SnO by distortions that split the octahedral site in the oxide into edge-sharing tetrahedral pairs. C1 IOWA STATE UNIV,AMES LAB,US DOE,AMES,IA 50011. NR 26 TC 16 Z9 16 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD AUG 13 PY 1997 VL 36 IS 17 BP 3730 EP 3734 DI 10.1021/ic970289u PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA XR238 UT WOS:A1997XR23800023 ER PT J AU Li, S Wu, HB Wang, LS AF Li, S Wu, HB Wang, LS TI Probing the electronic structure of metallocarbohedrenes: M8C12 (M=Ti, V, Cr, Zr, Nb) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID BINARY METAL METALLOCARBOHEDRENES; CARBON CLUSTER CATIONS; GAS-PHASE; TI8C12; STABILITY; TITANIUM; CARS; TI; CARBOHEDRENES; NANOCRYSTALS AB We report a systematic study of the electronic structure of the five metcars in the title using anion photoelectron spectroscopy, The electron affinities of the metcars are measured and are found to be metal dependent and increase from Ti8C12 to Cr8C12. The electronic structures of Zr8C12 and Nb8C12 are found to be similar to Ti8C12 and V8C12, respectively. All the spectra can be qualitatively interpreted by the molecular orbital schemes derived from a tetracapped tetrahedral M8C12 cluster. This work provides yet the most quantitative electronic and spectroscopic information about the metcars, as well as evidence supporting the tetrahedral structure for the metcars. C1 WASHINGTON STATE UNIV, DEPT PHYS, RICHLAND, WA 99352 USA. PACIFIC NW NATL LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 56 TC 52 Z9 53 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD AUG 13 PY 1997 VL 119 IS 32 BP 7417 EP 7422 DI 10.1021/ja9710159 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA XR118 UT WOS:A1997XR11800001 ER PT J AU Wang, HH Fox, SB Yagubskii, EB Kushch, LA Kotov, AI Whangbo, MH AF Wang, HH Fox, SB Yagubskii, EB Kushch, LA Kotov, AI Whangbo, MH TI Direct observation of the electron-donating property of the 5,6-dihydro-1,4-dithiin-2,3-dithiolate (dddt) ligands in square planar M(dddt)(2) complexes (M=Ni, Pd, Pt, and Au) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ORGANIC SUPERCONDUCTORS; METAL; SALTS; ANALOGS; NICKEL C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RUSSIAN ACAD SCI,INST CHEM PHYS,CHERNOGOLOVKA 142432,RUSSIA. N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. RP Wang, HH (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 25 TC 21 Z9 21 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD AUG 13 PY 1997 VL 119 IS 32 BP 7601 EP 7602 DI 10.1021/ja9704747 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XR118 UT WOS:A1997XR11800033 ER PT J AU Daneshvar, K Giess, EA Bacon, AM Dawes, DG Gea, LA Boatner, LA AF Daneshvar, K Giess, EA Bacon, AM Dawes, DG Gea, LA Boatner, LA TI Ion exchange in potassium titanyl phosphate SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL WAVE-GUIDES; 2ND-HARMONIC GENERATION; KTIOPO4 AB Ion-exchange processes in potassium titanyl phosphate (KTiOPO4 or KTP) single crystal immersed in Rb, Rb-Ba, Rb-Sr nitrate molten solutions have been investigated by using Rutherford backscattering depth-profile analysis. The depth to which Rb-ion exchange occurred in KTP was found to be sensitive to the presence of as little as 0.1% of a Ba impurity in a molten solution of rubidium nitrate. The addition of impurities such as Ba significantly increased the ion-exchange depth of Rb in KTP, and the Rb distribution after ion exchange. Using pure RbNO3, however, the depth of the Rb ion exchange was relatively shallow, and the Rb surface concentration was measurably greater at the minus than at the plus polar-axis faces of the crystal. These findings are relevant to the application of ion-exchange techniques to the fabrication of optical waveguides on KTP substrates. (C) 1997 American Institute of Physics. C1 LITTON AIRTRON SYNOPTICS,CHARLOTTE,NC 28273. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Daneshvar, K (reprint author), UNIV N CAROLINA,CHARLOTTE,NC 28223, USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 15 TC 10 Z9 10 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 11 PY 1997 VL 71 IS 6 BP 756 EP 758 DI 10.1063/1.119636 PG 3 WC Physics, Applied SC Physics GA XP969 UT WOS:A1997XP96900010 ER PT J AU Ejeckam, FE Seaford, ML Lo, YH Hou, HQ Hammons, BE AF Ejeckam, FE Seaford, ML Lo, YH Hou, HQ Hammons, BE TI Dislocation-free InSb grown on GaAs compliant universal substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID PSEUDOMORPHIC STRUCTURES; CRITICAL THICKNESS AB An innovative compliant GaAs substrate was formed by wafer bonding a 30 Angstrom GaAs layer to a bulk GaAs crystal with a large angular misalignment inserted about their common normals. InSb epitaxial layers, which is about 15% lattice mismatched to GaAs, have been grown on both compliant substrates and conventional GaAs substrates. Transmission electron microscopy studies showed that the InSb films grown on the compliant substrates have no measurable threading dislocations, whereas the InSb films on the conventional GaAs substrates exhibited dislocation densities as high as 10(11) cm(-2). The observations made here suggest that the defect-free heteroepitaxial growth of exceedingly large lattice-mismatched crystals can be achieved with compliant universal substrates. (C) 1997 American Institute of Physics. C1 SANDIA NATL LABS,DEPT SEMICOND MAT,ALBUQUERQUE,NM 87185. WRIGHT LABS,MAT DIRECTORATE,WRIGHT PATTERSON AFB,OH. CORNELL UNIV,CTR MAT SCI,ITHACA,NY 14853. CORNELL UNIV,NANOFABRICAT FACIL,ITHACA,NY 14853. RP Ejeckam, FE (reprint author), CORNELL UNIV,SCH ELECT ENGN,PHILLIPS HALL,ITHACA,NY 14853, USA. NR 10 TC 78 Z9 79 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 11 PY 1997 VL 71 IS 6 BP 776 EP 778 DI 10.1063/1.119642 PG 3 WC Physics, Applied SC Physics GA XP969 UT WOS:A1997XP96900017 ER PT J AU Golovlev, VV Allman, SL Garrett, WR Chen, CH AF Golovlev, VV Allman, SL Garrett, WR Chen, CH TI Laser-induced acoustic desorption of electrons and ions SO APPLIED PHYSICS LETTERS LA English DT Article ID MASS-SPECTROMETRY; GENERATION; PULSES AB Laser irradiation of absorbing materials can be used to generate acoustic pulses with extremely high amplitude and short pulse duration. Such acoustic pulses can transfer energy and momentum to atomic particles on solid surfaces to cause desorption of the particles. We report experimental observations of the effect of laser-induced acoustic desorption (LIAD) of electrons from metal film surfaces and hydrogen ions from the surface of palladium saturated with hydrogen. We believe LIAD can be used as a gentle technique to transfer analyte molecules and ions into gas phase for mass analysis and for other applications. (C) 1997 American Institute of Physics. RP Golovlev, VV (reprint author), OAK RIDGE NATL LAB,CHEM & BIOL PHYS SECT,BLDG 5500,OAK RIDGE,TN 37831, USA. RI Allman, Steve/A-9121-2011 OI Allman, Steve/0000-0001-6538-7048 NR 10 TC 30 Z9 31 U1 2 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 11 PY 1997 VL 71 IS 6 BP 852 EP 854 DI 10.1063/1.119667 PG 3 WC Physics, Applied SC Physics GA XP969 UT WOS:A1997XP96900043 ER PT J AU Luscombe, JH Luban, M AF Luscombe, JH Luban, M TI Wave-vector-dependent magnetic susceptibility of classical Heisenberg rings SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article AB We first extend previous results of GS Joyce so as to derive the exact wave-vector-dependent susceptibility chi(N)(q, T) for a ring of N classical Heisenberg spins with isotropic nearest-neighbour interactions. Our major result however is a simple, highly accurate, analytic approximation for chi(N)(q, T) which nevertheless preserves an associated sum rule over the Brillouin zone. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Luscombe, JH (reprint author), USN,POSTGRAD SCH,DEPT PHYS,MONTEREY,CA 93943, USA. NR 12 TC 12 Z9 12 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD AUG 11 PY 1997 VL 9 IS 32 BP 6913 EP 6920 DI 10.1088/0953-8984/9/32/013 PG 8 WC Physics, Condensed Matter SC Physics GA XQ903 UT WOS:A1997XQ90300013 ER PT J AU Wu, CH Liu, TB Chu, BJ Schneider, DK Graziano, V AF Wu, CH Liu, TB Chu, BJ Schneider, DK Graziano, V TI Characterization of the PEO-PPO-PEO triblock copolymer and its application as a separation medium in capillary electrophoresis SO MACROMOLECULES LA English DT Article ID OXIDE) BLOCK-COPOLYMERS; AQUEOUS-SOLUTION; POLY(ETHYLENE OXIDE); AGGREGATION BEHAVIOR; POLYMER-SOLUTIONS; GEL FORMATION; MICELLIZATION; DNA; PLURONIC-F127; TRANSITION AB The Pluronic polyol F127, PEO99PPO69PEO99 (PEG and PPO being poly(ethylene oxide) and poly(propylene oxide), respectively) has the potential to be used as an effective separation medium in capillary electrophoresis (CE) for the separation of biomacromolecules such as DNA fragments and proteins. Static light scattering (SLS), dynamic lightscattering (DLS), small-angle neutron scattering (SANS), and small-angle X-ray scattering (SAXS) were used to characterize the solution properties and the microstructures of F127 in the same electrophoresis buffer used in CE. In the dilute solution region, F127 in CE buffer forms micelles similar to that in water. At high solution concentrations, micelles tend to pack into some crystalline forms with relatively well-structured PPO centers. By using a combination of SANS and SAXS results, we are able to conclusively determine the gellike structure to have a face-centered cubic lattice. The effects of solvent, polymer concentration, temperature, and sample preparation procedure on the gel structure were studied. In the gellike region the aggregation number and also the micellar size are not sensitive to both the concentration change and the temperature change. The results of DNA electrophoretic migration in F127 gels also support these findings. C1 SUNY STONY BROOK,DEPT CHEM,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RI Liu, Tianbo/D-8915-2017 OI Liu, Tianbo/0000-0002-8181-1790 NR 43 TC 167 Z9 170 U1 10 U2 45 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD AUG 11 PY 1997 VL 30 IS 16 BP 4574 EP 4583 DI 10.1021/ma9701088 PG 10 WC Polymer Science SC Polymer Science GA XQ824 UT WOS:A1997XQ82400010 ER PT J AU Athreya, RM Kapahi, VK McCarthy, PJ vanBreugel, W AF Athreya, RM Kapahi, VK McCarthy, PJ vanBreugel, W TI Steep-spectrum radio cores in high-redshift galaxies SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies, nuclei; radio continuum, galaxies ID ACTIVE GALACTIC NUCLEI; MULTIFREQUENCY OBSERVATIONS; ENERGY-DISTRIBUTIONS; CONTINUUM; QUASARS; SCALE; BLAZARS AB We have made high-resolution radio images, using the Very Large Array (VLA), of a sample of radio galaxies at z > 2 selected from the MRC/1 Jy complete sample. These are also the first detailed observations of radio galaxies at the high rest-frame frequencies of 15-30 GHz. Compact (<0.2 arcsec) cores at the mJy and sub-mJy level were detected in most of the objects, coincident with the optical galaxies. In sharp contrast to the flat spectra of radio cores in galaxies at low redshift, we find that most of the cores at high redshift have a steep spectral index (alpha > 0.5) between 4.7 and 8.3 GHz (observed). We identify this steepening with the optically thin part of a synchrotron self-absorbed spectrum at frequencies above the turnover. Both core- and lobe-dominated quasars have also been reported to show such a turnover from flat to steep spectra but at much higher observed frequencies. We suggest that the cores in galaxies and quasars are intrinsically similar (in the rest frame of the emitting plasma) and that the observed differences can be explained in terms of Doppler shifting by different amounts in quasar and galaxy cores. This model is consistent with the unification scheme for radio galaxies and quasars. Using the theory of synchrotron self-absorption we estimate sizes of similar to 1 pc, magnetic fields of similar to 1 G and electron densities of similar to 1000 cm(-3) for the cores of both quasars and radio galaxies. The similar values are perhaps an indication of similar physical processes and parameters in their cores. The spectrum at turnover provides information on scales much smaller than the telescope resolution. It is therefore a useful tool for probing the cores of galaxies which are usually too weak for very long-baseline interferometry studies. C1 OBSERV CARNEGIE INST WASHINGTON,PASADENA,CA 91107. LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP Athreya, RM (reprint author), NATL CTR RADIO ASTROPHYS TIFR,PO BAG 3,PUNE 411007,MAHARASHTRA,INDIA. NR 33 TC 25 Z9 25 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 11 PY 1997 VL 289 IS 3 BP 525 EP 534 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XR490 UT WOS:A1997XR49000004 ER PT J AU Schlueter, RD Humphries, D Tanabe, J AF Schlueter, RD Humphries, D Tanabe, J TI Pure permanent magnet harmonics corrector ring SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID COBALT AB A concept for creating any desired harmonics mix ir, a pure permanent magnet (PM) corrector ring is presented. Useful for nulling various harmonics simultaneously, such a device is versatile for many accelerator applications. The harmonic mix can be changed without redesign or replacement by a new ring or parts and, if desired, can be accomplished in situ via remote control of cylinder motors. Harmonics suppression of greater than a factor of 100 or even 1000 are possible; exact functional dependencies of harmonics suppresion capability versus magnet geometry are given. Sensitivity to positioning and corrector ring PM errors are given, and shown to be themselves nullable. RP Schlueter, RD (reprint author), UNIV CALIF BERKELEY,EO LAWRENCE BERKELEY NATL LAB,1 CYCLOTRON RD,MS 46-161,BERKELEY,CA 94720, USA. NR 7 TC 7 Z9 7 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 AUG 11 PY 1997 VL 395 IS 2 BP 153 EP 158 DI 10.1016/S0168-9002(97)00020-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XV836 UT WOS:A1997XV83600001 ER PT J AU Baer, H Chen, CH Drees, M Paige, F Tata, X AF Baer, H Chen, CH Drees, M Paige, F Tata, X TI Collider phenomenology for supersymmetry with large tan beta SO PHYSICAL REVIEW LETTERS LA English DT Article ID GLUINO DECAYS; SUPERGRAVITY; P(P)OVER-BAR; SQUARK; SEARCH AB If the parameter tan beta of the minimal supersymmetric model is large, then b and tau Yukawa interactions are important. These can significantly modify the masses and decays of sparticles. We describe new calculations which allow a reliable exploration of large tan beta values, and discuss implications for collider experiments. For large values of tan beta, charginos and neutralinos may dominantly decay to tau leptons or b quarks. The usual cross sections for multilepton signatures may be greatly reduced, but supersymmetry may be detectable via new signals involving tau's or b's in the final state. C1 UNIV CALIF DAVIS,DAVIS INST HIGH ENERGY PHYS,DAVIS,CA 95616. APCTP,SEOUL 130012,SOUTH KOREA. BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV HAWAII,DEPT PHYS & ASTRON,HONOLULU,HI 96822. RP Baer, H (reprint author), FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306, USA. NR 24 TC 111 Z9 112 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 AUG 11 PY 1997 VL 79 IS 6 BP 986 EP 989 DI 10.1103/PhysRevLett.79.986 PG 4 WC Physics, Multidisciplinary SC Physics GA XP977 UT WOS:A1997XP97700007 ER PT J AU Lu, ZT Corwin, KL Vogel, KR Wieman, CE Dinneen, TP Maddi, J Gould, H AF Lu, ZT Corwin, KL Vogel, KR Wieman, CE Dinneen, TP Maddi, J Gould, H TI Efficient collection of Fr-221 into a vapor cell magneto-optical trap SO PHYSICAL REVIEW LETTERS LA English DT Article ID ATOMIC-BEAM; LASER; ISOTOPES; FRANCIUM AB We have efficiently loaded a vapor cell magneto-optical trap from an orthotropic source of Fr-221 with a trapping efficiency of 56(10)%. A novel detection scheme allowed us to measure 900 trapped atoms with a signal to noise ratio of similar to 60 in 1 sec. We have measured the energies and the hyperfine constants of the 7(2)P(1/2) and 7(2)P(3/2) states. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Lu, ZT (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Corwin, Kristan/A-1331-2013 NR 23 TC 76 Z9 76 U1 2 U2 11 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 AUG 11 PY 1997 VL 79 IS 6 BP 994 EP 997 DI 10.1103/PhysRevLett.79.994 PG 4 WC Physics, Multidisciplinary SC Physics GA XP977 UT WOS:A1997XP97700009 ER PT J AU Phillips, CK Scott, SD Bell, MG Wilson, JR Bell, R Bush, CE Duong, HH Hosea, JC Jassby, D Majeski, R Medley, SS Park, H Petrov, MP Ramsey, A Rogers, JH Schilling, G Skinner, CH Synakowski, E Taylor, G AF Phillips, CK Scott, SD Bell, MG Wilson, JR Bell, R Bush, CE Duong, HH Hosea, JC Jassby, D Majeski, R Medley, SS Park, H Petrov, MP Ramsey, A Rogers, JH Schilling, G Skinner, CH Synakowski, E Taylor, G TI Scaling of confinement with isotopic content in deuterium and tritium plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID FUSION TEST REACTOR; GYRO-BOHM; TRANSPORT; TFTR AB Global energy confinement time in plasmas heated with waves in the ion cyclotron range of frequencies in the Tokamak Fusion Test Reactor is 8%-11% higher in deuterium-tritium (D-T) than in deuterium (D) only plasmas. Kinetic analysis based on local equilibrium profile measurements indicates that the increase in stored energy is almost entirely in the electron component and that the electron thermal diffusivity chi(e) is smaller in D-T than in D plasmas. The implied scaling of chi(e) with normalized ion gyro radius rho* is opposite to that observed in Joint European Torus (JET) and DIII-D tokamaks when rho* was varied by changing the magnetic field strength. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37830. GEN ATOM CO,SAN DIEGO,CA 92101. AF IOFFE PHYS TECH INST,ST PETERSBURG 194021,RUSSIA. RP Phillips, CK (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 14 TC 3 Z9 3 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 AUG 11 PY 1997 VL 79 IS 6 BP 1050 EP 1053 DI 10.1103/PhysRevLett.79.1050 PG 4 WC Physics, Multidisciplinary SC Physics GA XP977 UT WOS:A1997XP97700023 ER PT J AU Berryman, JG AF Berryman, JG TI Generalization of Eshelby's formula for a single ellipsoidal elastic inclusion to poroelasticity and thermoelasticity SO PHYSICAL REVIEW LETTERS LA English DT Article ID POROUS-MEDIA; SCATTERING; EQUATIONS; WAVES AB Eshelby's formula gives the response of a single ellipsoidal elastic inclusion in an elastic whole space to a uniform strain imposed at infinity. Using a linear combination of results from two simple thought experiments, we show how this formula may be generalized to both poroelasticity and thermoelasticity. The resulting new formulas are important for applications to analysis of poroelastic and thermoelastic composites, including but not restricted to rocks. RP LAWRENCE LIVERMORE NATL LAB, POB 808 L-202, LIVERMORE, CA 94551 USA. RI Berryman, James/A-9712-2008 NR 27 TC 26 Z9 27 U1 1 U2 3 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 AUG 11 PY 1997 VL 79 IS 6 BP 1142 EP 1145 DI 10.1103/PhysRevLett.79.1142 PG 4 WC Physics, Multidisciplinary SC Physics GA XP977 UT WOS:A1997XP97700046 ER PT J AU Ovchinnikov, YN Dyugaev, AM Fulde, P Kresin, VZ AF Ovchinnikov, YN Dyugaev, AM Fulde, P Kresin, VZ TI Properties of a magnetic impurity in a metal SO JETP LETTERS LA English DT Article AB The effect of a polarized conduction-electron cloud back on a magnetic impurity dissolved in a metal is studied. It is shown that at a temperature T-c much higher than the Kondo temperature the system becomes unstable against symmetry breaking and that a state with (S-z) not equal 0 is established. The behavior of (S-z) is derived for all temperatures and magnetic fields except for a very narrow region around T-c and for very low temperatures. The minute role of Kondo-type processes in establishing the symmetry-broken state is pointed out. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RUSSIAN ACAD SCI,LANDAU INST THEORET PHYS,MOSCOW 117334,RUSSIA. RP Ovchinnikov, YN (reprint author), MAX PLANCK INST PHYS KOMPLEXER SYST,D-01187 DRESDEN,GERMANY. NR 6 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-3640 J9 JETP LETT+ JI Jetp Lett. PD AUG 10 PY 1997 VL 66 IS 3 BP 195 EP 201 DI 10.1134/1.567501 PG 7 WC Physics, Multidisciplinary SC Physics GA XW687 UT WOS:A1997XW68700012 ER PT J AU Durham, WB AF Durham, WB TI Laboratory observations of the hydraulic behavior of a permeable fracture from 3800 m depth in the KTB pilot hole SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID FLUID-FLOW; CRYSTALLINE; SAMPLES; JOINTS; ROCK AB A thorough search through core recovered from the German Continental Deep Drilling Program (KTB) pilot hole in the vicinity of the high-permeability zone near 3800 m depth revealed three intervals containing undisturbed fractures that had the appearance of high-permeability fluid conduits. We report here a detailed study in the laboratory of one of those fractures, an epidote-filled fracture in amphibolite, aimed at determining if the fracture was fluid conducting at in situ stresses and, if so, what characteristics of the fracture allowed it to remain open over geologic times. We found that the presence of the fracture made the core sample 4-7 orders of magnitude more permeable than the host rock at confining pressures near 100 MPa. Fine scale measurements of the shape of the fracture aperture, made with a specially designed profilometer, suggest that water flows through a distributed network of very small (order of 1 mm) high-aspect-ratio (order of 10) channels that cover 30-70% of the fracture surface. In contrast, fresh, well-mated fractures in granite at comparable conditions and for a comparable amount of fracture closure are slightly more compliant normal to the fracture plane and more prone to concentrate flow into channels than the mineralized fracture, suggesting fundamentally different hydraulic conduction mechanisms in fresh versus mineralized fluid-conducting fractures. RP Durham, WB (reprint author), LAWRENCE LIVERMORE NATL LAB, POB 808, L-201, LIVERMORE, CA 94550 USA. NR 18 TC 33 Z9 33 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD AUG 10 PY 1997 VL 102 IS B8 BP 18405 EP 18416 DI 10.1029/96JB02813 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XQ830 UT WOS:A1997XQ83000050 ER PT J AU Park, JH Kim, DH Shim, SY Kim, YH Lee, JM Hahn, TS Hettinger, JD Steel, DG Gray, KE Glagola, B Lee, J Khim, ZG AF Park, JH Kim, DH Shim, SY Kim, YH Lee, JM Hahn, TS Hettinger, JD Steel, DG Gray, KE Glagola, B Lee, J Khim, ZG TI Enhanced transport properties in YBa2Cu3Ox films with crossed columnar defects of various inclination angles SO PHYSICA C LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; LINEAR DEFECTS; ION IRRADIATION; VORTEX MOTION; CRYSTALS; CONFIGURATIONS; CURRENTS; SPLAY AB We have studied the effect of heavy-ion irradiation on the transport properties of YBa2Cu3Ox thin films. Columnar defects parallel to the c axis (0 degrees) and crossed columnar defects with various inclination angles (theta = +/- 10 degrees, +/- 20 degrees, and +/- 40 degrees) were introduced into films by 1.3 GeV U-ion irradiation with dose equivalent to 1 T vortex density. Transport properties including irreversibility fields, activation energies, and critical current densities have been measured in magnetic fields applied parallel to the c axis. The best transport properties were observed in samples of theta = +/- 10 degrees in most of the H-T plane we studied, consistent with the splay model. However, the relative enhancement of the critical current density in the theta = +/- 10 degrees compared to the 0 degrees sample was not as large as in the case of a single crystal suggesting that in films the point defects also play an important part in flux pinning. (C) 1997 Elsevier Science B.V. C1 YEUNGNAM UNIV,KYONGSAN 712749,SOUTH KOREA. KOREA ADV INST SCI & TECHNOL,SEOUL 131791,SOUTH KOREA. ROWAN COLL,GLASSBORO,NJ 08028. ARGONNE NATL LAB,ARGONNE,IL 60439. SEOUL NATL UNIV,SEOUL 151742,SOUTH KOREA. NR 16 TC 13 Z9 13 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG 10 PY 1997 VL 281 IS 4 BP 310 EP 316 DI 10.1016/S0921-4534(97)01482-2 PG 7 WC Physics, Applied SC Physics GA YD497 UT WOS:A1997YD49700006 ER PT J AU Wasserman, E Rustad, JR Felmy, AR Hay, BP Halley, JW AF Wasserman, E Rustad, JR Felmy, AR Hay, BP Halley, JW TI Ewald methods for polarizable surfaces with application to hydroxylation and hydrogen bonding on the (012) and (001)surfaces of alpha-Fe2O3 SO SURFACE SCIENCE LA English DT Article DE computer simulations; iron oxide; low index single crystal surfaces; molecular dynamics; single crystal surfaces; surface relaxation and reconstruction ID MOLECULAR STATICS CALCULATIONS; ABINITIO CHARACTERIZATION; PHOSPHATE ADSORPTION; ELECTRONIC-STRUCTURE; DYNAMICS SIMULATION; WATER CLUSTERS; IONIC-CRYSTAL; HEMATITE; ALPHA-AL2O3; MODEL AB We present a clear and rigorous derivation of the Ewald-like method for calculation of the electrostatic energy of the systems infinitely periodic in two dimensions and of finite size in the third dimension (slabs). We have generalized this method originally developed by Rhee et al. (Phys. Rev. B 40 (1989) 36) to account for charge-dipole and dipole-dipole interactions and therefore made it suitable for treatment of polarizable systems. This method has the advantage over exact methods of being significantly faster and therefore appropriate for large-scale molecular dynamics simulations. However, it involves a Taylor expansion which has to be demonstrated to be of sufficient order. The method was extensively benchmarked against the exact methods by Leckner and Parry. We found it necessary to increase the order of the multipole expansion from 4 (as in the original work by Rhee et al.) to 6. In this case the method is adequate for aspect ratios (thickness/shortest side length of the unit cell) less than or equal to 0.5. Molecular dynamics simulations using the transferable/polarizable model by Rustad et al. were applied to study the surface relaxation of the nonhydroxylated, hydroxylated and solvated surfaces of alpha-Fe2O3 (hematite). We find that our nonhydroxylated structures and energies are in good agreement with previous LDA calculations on alpha-alumina by Manassidis et al. (Surf. Sci. 285 (1993) L517). Using the results of molecular dynamics simulations of solvated interfaces, we define end-member hydroxylated-hydrated states for the surfaces which are used in energy minimization calculations. We find that hydration has a small effect on the surface structure, but that hydroxylation has a significant effect. Our calculations, both for gas-phase and solution-phase adsorption, predict a greater amount of hydroxylation for the alpha-Fe2O3 (012) surface than for the (001) surface. Our simulations also indicate the presence of four-fold coordinated iron ions on the (001) surface. (C) 1997 Elsevier Science B.V. C1 UNIV MINNESOTA, DEPT PHYS, MINNEAPOLIS, MN 55455 USA. UNIV MINNESOTA, MINNESOTA SUPERCOMP INST, MINNEAPOLIS, MN 55455 USA. RP Wasserman, E (reprint author), PACIFIC NW LAB, EMSL K8 96, POB 999, RICHLAND, WA 99352 USA. NR 50 TC 76 Z9 78 U1 1 U2 33 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD AUG 10 PY 1997 VL 385 IS 2-3 BP 217 EP 239 DI 10.1016/S0039-6028(97)00144-1 PG 23 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA YB535 UT WOS:A1997YB53500018 ER PT J AU Hrbek, J Schmid, AK Bartelt, MC Hwang, RQ AF Hrbek, J Schmid, AK Bartelt, MC Hwang, RQ TI STM study of Au growth on S-modified Ru(0001) SO SURFACE SCIENCE LA English DT Article DE Auger electron spectroscopy; chemisorption; epitaxy; gold; growth; nucleation; ruthenium; scanning tunneling microscopy; sulfur; surface diffusion; surface segregation ID BY-LAYER GROWTH; SURFACTANT-MEDIATED GROWTH; ENHANCED NUCLEATION; EPITAXIAL-GROWTH; SULFUR; AG; SUBMONOLAYER; AG(111); FILMS; DEPOSITION AB We present results of a detailed scanning tunneling microscopy (STM) study of submonolayer nucleation and growth of two-dimensional Au islands during deposition on clean versus S-precovered Ru(0001), at room temperature. In the presence of tiny amounts of S, a dramatic increase in the mean island densities is observed, corresponding to a decrease in the effective mobility of Au on Ru(0001). As imaged also by STM, the structure of the S adlayer changes during Au deposition, from a dilute lattice-gas, at low Au coverages, to an increasingly denser sequence of ordered superstructure p(2 x 2), (root 3 x root 3-R30 degrees) and c(2 x 4) domains, with increasing Au coverage. These findings suggest that the deposited Au atoms displace S adatoms, compressing S domains, a phenomenon consistent with a net repulsive interaction between neighboring Au and S mediated by the Ru substrate. (C) 1997 Elsevier Science B.V. C1 SANDIA NATL LABS,SURFACE CHEM DEPT,LIVERMORE,CA 94550. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RI Hrbek, Jan/I-1020-2013 NR 30 TC 15 Z9 15 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD AUG 10 PY 1997 VL 385 IS 2-3 BP L1002 EP L1009 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA YB535 UT WOS:A1997YB53500013 ER PT J AU Shen, Z Pinhero, PJ Lograsso, TA Delaney, DW Jenks, CJ Thiel, PA AF Shen, Z Pinhero, PJ Lograsso, TA Delaney, DW Jenks, CJ Thiel, PA TI The five-fold surface of quasicrystalline AlCuFe: preparation and characterization with LEED and AES SO SURFACE SCIENCE LA English DT Article DE alloys; aluminum; low energy electron diffraction (LEED); metallic surfaces ID AL-CU-FE; SINGLE QUASI-CRYSTALS; PHASE-DIAGRAM; AL68PD23MN9; ORDER; ALLOY; APPROXIMANTS; DIFFRACTION; TRANSITION; SYMMETRY AB We report the first surface characterization of a large, single-grain sample of quasicrystalline AlCuFe. The sample is oriented with its surface perpendicular to a five-fold axis, and has the bulk composition 63.4-24.0-12.6 at%. Following our method of preparation, the surface yields an exceptionally sharp and rich five-fold pattern in low-energy electron diffraction. The spot spacings and symmetries are consistent with expectations for this surface, based upon the unreconstructed structure. (C) 1997 Elsevier Science B.V. C1 IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV,DEPT MAT SCI & ENGN,AMES,IA 50011. IOWA STATE UNIV,AMES LAB,AMES,IA 50011. NR 37 TC 24 Z9 24 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD AUG 10 PY 1997 VL 385 IS 2-3 BP L923 EP L929 DI 10.1016/S0039-6028(97)00292-6 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA YB535 UT WOS:A1997YB53500001 ER PT J AU SchweitzerStenner, R Stichternath, A Dreybrodt, W Jentzen, W Song, XZ Shelnutt, JA Nielsen, OF Medforth, CJ Smith, KM AF SchweitzerStenner, R Stichternath, A Dreybrodt, W Jentzen, W Song, XZ Shelnutt, JA Nielsen, OF Medforth, CJ Smith, KM TI Raman dispersion spectroscopy on the highly saddled nickel(II)-octaethyltetraphenylporphyrin reveals the symmetry of nonplanar distortions and the vibronic coupling strength of normal modes SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PORPHYRIN FORCE-FIELD; LIGHT-ABSORPTION PROPERTIES; RESONANCE RAMAN; EXCITATION PROFILES; DEPOLARIZATION RATIO; ISOTOPE SHIFTS; PHOTOSYNTHETIC CHROMOPHORES; NICKEL OCTAETHYLPORPHYRIN; ASYMMETRIC PERTURBATIONS; STRUCTURAL PARAMETERS AB We have measured the polarized Raman cross sections and depolarization ratios of 16 fundamental modes of nickel octaethyltetraphenylporphyrin in a CS2 solution for 16 fundamental modes, i.e., the A(1g)-type vibrations nu(1), nu(2), nu(3), nu(4), nu(5), and phi(8), the B-1g vibrations nu(11) and nu(14), the B-2g vibrations nu(28), nu(29), and nu(30) and the antisymmetric A(2g) modes nu(19), nu(20), nu(22), and nu(23) function of the excitation wavelength. The data cover the entire resonant regions of the Q- and B-bands. They were analyzed by use of a theory which describes intra- and intermolecular coupling in terms of a time-independent nonadiabatic perturbation theory [E. Unger, U. Bobinger, W. Dreybrodt, and R. Schweitzer-Stenner, J. Phys. Chem. 97, 9956 (1993)]. This approach explicitly accounts in a self-consistent way for multimode mixing with all Raman modes investigated. The vibronic coupling parameters obtained from this procedure were then used to successfully fit the vibronic side bands of the absorption spectrum and to calculate the resonance excitation profiles in absolute units. Our results show that the porphyrin macrocycle is subject to B-2u-(saddling) and B-1u-(ruffling) distortions which lower its symmetry to S-4 Thus, evidence is provided that the porphyrin molecule maintains the nonplanar structure of its crystal phase in an organic solvent. The vibronic coupling parameters indicate a breakdown of the four-orbital model. This notion is corroborated by (ZINDO/S) calculations which reveal that significant configurational interaction occurs between the electronic transitions into \Q]- and \1B]-states and various porphyrin-->porphyrin, metal-->porphyrin, and porphyrin-->metal transitions. The intrastate coupling parameters are used to estimate the excited electronic states' displacements along the normal coordinates with respect to the ground state and their contributions to the reorganization energy, It turns out that the \B]-state is predominantly affected by symmetric A(1g)-displacements, whereas the \Q]-state is subject to A(2g), B-1g, and B-2g displacements of its equilibrium configuration. While the former is induced by the combined effect of ruffling and saddling, the latter arises from Jahn-Teller coupling within the degenerate states. (C) 1997 American Institute of Physics. C1 SANDIA NATL LABS, FUEL SCI DEPT, ALBUQUERQUE, NM 87185 USA. UNIV COPENHAGEN, DEPT CHEM, DK-2100 COPENHAGEN, DENMARK. UNIV CALIF DAVIS, DEPT CHEM, DAVIS, CA 95616 USA. UNIV NEW MEXICO, DEPT CHEM, ALBUQUERQUE, NM 87131 USA. RP SchweitzerStenner, R (reprint author), UNIV BREMEN, FBI INST EXPT PHYS, D-28359 BREMEN, GERMANY. RI Shelnutt, John/A-9987-2009; Medforth, Craig/D-8210-2013; REQUIMTE, FMN/M-5611-2013; REQUIMTE, UCIBIO/N-9846-2013; Nielsen, Ole /D-8980-2015; Smith, Kevin/G-1453-2011 OI Shelnutt, John/0000-0001-7368-582X; Medforth, Craig/0000-0003-3046-4909; Nielsen, Ole /0000-0001-8839-8671; Smith, Kevin/0000-0002-6736-4779 NR 63 TC 35 Z9 36 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 8 PY 1997 VL 107 IS 6 BP 1794 EP 1815 DI 10.1063/1.474532 PG 22 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP280 UT WOS:A1997XP28000013 ER PT J AU Parks, EK Nieman, GC Kerns, KP Riley, SJ AF Parks, EK Nieman, GC Kerns, KP Riley, SJ TI Reactions of Ni-38 with N-2, H-2, and CO: Cluster structure and adsorbate binding sites SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SMALL NICKEL CLUSTERS; IRON CLUSTERS; ADSORPTION; HYDROGEN; SURFACE; NI(100) AB The gas-phase reactions of nitrogen, hydrogen, and carbon monoxide with Ni-38 are studied as a function of reagent pressure at several reaction temperatures. Saturation coverage of the cluster is found at Ni-38(N-2)(24), Ni38H36, and Ni-38(CO)(36). These saturation levels are consistent with the metal core of the ligated cluster having the structure of a truncated octahedron in each case. An alternate fee structure derived from a 40-atom truncated tetrahedron is consistent with the nitrogen data, but not with the hydrogen or carbon monoxide results. In addition, the nitrogen uptake data indicate that the bare Ni-38 cluster also has the structure of a truncated octahedron or possibly a deformed truncated octahedron. There is no indication that Ni-38 has an icosahedral or polyicosahedral structure. The nature of the binding of the three reagents to the cluster is discussed. Evidence is presented that CO initially binds to atop sites, but following saturation of thesesites a local rearrangement to bridge sites occurs that allows an increase in coverage to the observed saturation at Ni-38(CO)(36) At high reagent pressures all three reagents cause adsorbate-induced structural changes to isomers that bind more ligands and whose structures have yet to be determined. (C) 1997 American Institute of Physics. C1 MONMOUTH COLL, DEPT CHEM, MONMOUTH, IL 61462 USA. RP Parks, EK (reprint author), ARGONNE NATL LAB, DIV CHEM, 9700 S CASS AVE, ARGONNE, IL 60439 USA. NR 29 TC 63 Z9 65 U1 2 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 8 PY 1997 VL 107 IS 6 BP 1861 EP 1871 DI 10.1063/1.474536 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP280 UT WOS:A1997XP28000018 ER PT J AU Wei, SH Zunger, A AF Wei, SH Zunger, A TI Point-ion versus density functional calculations of electric field gradients in ordered GaInP2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PLANE-WAVE METHOD; GROUND-STATE; YBA2CU3O7; ALLOYS AB We investigate whether the electric field gradient (EFG) at an atomic site in the unit cell of a periodic solid can be modeled via the electrostatic field gradient set up by atomic point charges outside that site. To test this approach we contrast the EFG predicted by such point-ion models for long-range ordered GaInP2 alloys with the results obtained from self-consistent all-electron calculations in the local density approximation (LDA). We first tested our LDA approach for ZnAl2O4, for which experimental data exist, finding the quadrupole coupling constant Q(cc)(Al-27)=3.94 MHz, compared with the measured value of \Q\ = 3.68 MHz. Applying next the LDA approach to perfectly ordered GaInP2 (for which experimental data do not exist), we find the LDA quadrupole coupling constant Q(cc) = -4.83, -2.84, and 13.08 MHz for Ga-69, Ga-71, and In-115, respectively. We further find that more than 95% of these EFGs originate from the anisotropic electron charge distribution within a small sphere of radius similar to 0.2 Angstrom about the respective atomic site. Hence, the point-ion model significantly underestimates the magnitude of the EFG (and in some cases also gives an incorrect sign). The point-ion model also fails in reproducing the relative trends in the EFG as the crystal structure changes. We conclude that the point-ion model is not a viable alternative to calculate EFG in periodic covalent solids. (C) 1997 American Institute of Physics. RP Wei, SH (reprint author), NATL RENEWABLE ENERGY LAB, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 29 TC 8 Z9 8 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 8 PY 1997 VL 107 IS 6 BP 1931 EP 1935 DI 10.1063/1.474544 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP280 UT WOS:A1997XP28000026 ER PT J AU Thompson, WH Miller, WH AF Thompson, WH Miller, WH TI On the 'direct' calculation of thermal rate constants .2. The flux-flux autocorrelation function with absorbing potentials, with application to the O+HCl->OH+Cl reaction (vol 106, pg 142, 1997) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction, Addition C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Thompson, WH (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. NR 7 TC 20 Z9 21 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 8 PY 1997 VL 107 IS 6 BP 2164 EP 2165 DI 10.1063/1.474568 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP280 UT WOS:A1997XP28000050 ER PT J AU Wang, GJ Volkow, ND Fowler, JS Fischman, M Foltin, R Abumrad, NN Logan, J Pappas, NR AF Wang, GJ Volkow, ND Fowler, JS Fischman, M Foltin, R Abumrad, NN Logan, J Pappas, NR TI Cocaine abusers do not show loss of dopamine transporters with age SO LIFE SCIENCES LA English DT Article DE age; cocaine abuser; [C-11]cocaine; dopamine transporter; positron emission tomography ID BINDING-SITES; BRAIN; 1-METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE; INHIBITORS; BLOCKERS; NEURONS; USERS; TIME; PET AB Cocaine blocks dopamine transporters (DAT) and this effect is crucial to its reinforcing properties. To assess the effects of chronic cocaine on DAT we evaluated 20 current cocaine abusers and 20 age matched controls using PET and [C-11]cocaine as a DAT Ligand. Though there were no differences in DAT availability between groups, current cocaine abusers (and 12 detoxified cocaine abusers studied previously) did not show the typical age-related decline in DAT seen in controls. Though further studies are required to rule out sampling effects and to control for confounding variables (i.e. smoking), one could speculate that chronic DAT blockade by cocaine has a protective effect on the loss of DAT with age. C1 BROOKHAVEN NATL LAB,DEPT CHEM,NEW YORK,NY 11973. SUNY STONY BROOK,DEPT RADIOL,STONY BROOK,NY 11794. SUNY STONY BROOK,DEPT PSYCHIAT,STONY BROOK,NY 11794. COLUMBIA UNIV,DEPT PSYCHIAT,NEW YORK,NY 10027. NORTHSHORE UNIV HOSP,DEPT SURG,MANHASSET,NY. RP Wang, GJ (reprint author), BROOKHAVEN NATL LAB,DEPT MED,NEW YORK,NY 11973, USA. FU NIDA NIH HHS [5RO1-DA06891] NR 33 TC 25 Z9 25 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0024-3205 J9 LIFE SCI JI Life Sci. PD AUG 8 PY 1997 VL 61 IS 11 BP 1059 EP 1065 DI 10.1016/S0024-3205(97)00614-0 PG 7 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA XR872 UT WOS:A1997XR87200005 PM 9307051 ER PT J AU Choi, W AF Choi, W TI On the fission of algebraic solitons SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID INTERNAL SOLITARY WAVES; DE VRIES EQUATION; UNEVEN BOTTOM; ATMOSPHERE AB The fission of an algebraic internal soliton climbing onto a shelf in a two-fluid system of infinite depth is investigated. It is shown that, by using conservation laws of the Benjamin-Ono equation with variable coefficients, we can predict the number of solitons emerging from an incident solitary wave and their amplitudes. These predictions are also verified with numerical solutions. C1 LOS ALAMOS NATL LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. RP Choi, W (reprint author), LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. NR 21 TC 0 Z9 0 U1 1 U2 2 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD AUG 8 PY 1997 VL 453 IS 1963 BP 1753 EP 1762 DI 10.1098/rspa.1997.0094 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ910 UT WOS:A1997XQ91000011 ER PT J AU Matzger, AJ Vollhardt, KPC AF Matzger, AJ Vollhardt, KPC TI From phenylenes to acenes: Flash vacuum pyrolytic isomerization of angular [3]phenylene to benzo[ghi]fluoranthene SO CHEMICAL COMMUNICATIONS LA English DT Article ID CYCLOHEXATRIENE RING; INTERMEDIACY AB The flash vacuum pyrolysis of angular [3]phenylene and bis(2-ethynylphenyl)ethyne produces benzo[ghi]fluoranthene and chrysene, respectively. C1 UNIV CALIF BERKELEY,DEPT CHEM,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Matzger, Adam/G-7497-2016 OI Matzger, Adam/0000-0002-4926-2752 NR 20 TC 17 Z9 17 U1 0 U2 3 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD AUG 7 PY 1997 IS 15 BP 1415 EP 1416 DI 10.1039/a702680c PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XP047 UT WOS:A1997XP04700040 ER PT J AU Pilgrim, JS Taatjes, CA AF Pilgrim, JS Taatjes, CA TI Infrared absorption probing of the Cl+C3H6 reaction: Rate coefficient for HCl production between 290 and 800 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID UNIMOLECULAR ELIMINATION-REACTIONS; CHLORINE ATOMS; LASER; RADICALS; PHOTOFRAGMENTATION; ABSTRACTION; DYNAMICS; EMISSION; SPECTRA; SYSTEM AB The reaction of Cl with propylene, C3H6, has been investigated as a function of temperature (293-800 K) and pressure (3-10 Torr) using the laser photolysis/infrared long-path absorption (LP/IRLPA) technique. The measured rate coefficient for HCl production is well-described by a simple Arrhenius expression (4.9 +/- 0.5) x 10(-11) exp[-(90 +/- 50)/T] cm(3) molecule(-1) s(-1) (all error estimates +/- 2 sigma). At T less than or equal to 400 K biexponential time behavior of the HCl production is observed, arising from excited C3H6Cl adduct dissociation, but at higher temperature single-exponential behavior is seen. Comparison of measurements in CO2. buffer, where HCl vibrational relaxation is rapid, and in Ar buffer allows extraction of the HCl(upsilon = 1) + C3H6 vibrational relaxation rate and the fraction of vibrationally excited HCl produced in the reaction. The measured rate coefficient for HCl(upsilon=1) vibrational relaxation by C3H6 is (3.7 +/- 0.7) x 10(-12) cm(3) molecule(-1) s(-1), and the fraction of vibrationally excited HCl produced in the reaction is 0.48 +/- 0.06 at 293 K. The observations are consistent with a dominant direct abstraction mechanism and a smaller contribution from addition-elimination. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. NR 37 TC 39 Z9 39 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 7 PY 1997 VL 101 IS 32 BP 5776 EP 5782 DI 10.1021/jp971405h PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP915 UT WOS:A1997XP91500010 ER PT J AU Jentzen, W Unger, E Song, XZ Jia, SL TurowskaTyrk, I SchweitzerStenner, R Dreybrodt, W Scheidt, WR Shelnutt, JA AF Jentzen, W Unger, E Song, XZ Jia, SL TurowskaTyrk, I SchweitzerStenner, R Dreybrodt, W Scheidt, WR Shelnutt, JA TI Planar and nonplanar conformations of (meso-tetraphenylporphinato)nickel(II) in solution as inferred from solution and solid-state Raman spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PORPHYRIN FORCE-FIELD; RESONANCE RAMAN; VIBRATIONAL FREQUENCIES; NICKEL(II) PORPHYRINS; DEPOLARIZATION RATIO; ISOTOPE SHIFTS; HEME-PROTEINS; SPIN STATE; OCTAETHYLPORPHYRIN; SPECTRA AB The coexistence in solution of at least two conformers of (meso-tetraphenylporphinato)nickel(II) [Ni(TPP)] is inferred from solution and single-crystal resonance Raman spectra obtained at different temperatures (170 - 297 K) and excitation wavelengths (413.1 and 457.9 nm). The shapes of the structure-sensitive Raman lines v(8) and v(2) are clearly asymmetric and change with temperature. These broad lines can be decomposed into at least two sublines, a low-frequency (LF) and a high-frequency (HF) component. In contrast, the corresponding single-crystal Raman lines of the nonplanar structure of Ni(TPP) in the crystal are narrow and symmetric. For the line v(2), the broad LF subline results from nonplanar conformers and the narrow HF subline arises from a more planar conformer. This assignment is consistent with the observation that the LF subline of v(2) is more enhanced upon changing the excitation wavelength from 413.1 to 457.9 nm. The selective resonance enhancement is caused by the red shifts of the UV-visible absorption bands and Raman excitation profiles of the nonplanar form. The frequency assignment for the sublines of vs is reversed from that of v(2) (i.e., the HF subline of v(8) arises from nonplanar conformers and the LF subline results from a more planar macrocycle). This assignment is based on subline broadness and enhancement behavior using an excitation wavelength located on the red side of the B band. The assignments of the sublines to the nonplanar conformer are also in agreement with the Raman spectra of single crystals in which Ni(TPP) is known from X-ray crystallography to have a predominantly ruffled nonplanar conformation. Specifically, the frequencies of the sublines of v(8) and v(2) that are assigned to the nonplanar form in solution closely match the frequencies of Ni(TPP) in the single crystal. We propose two thermodynamic models for the interpretation of the temperature dependence of the intensity ratios of the sublines. A two-state model assumes one planar and one nonplanar conformer in solution. From the slopes in the van't Hoff plots, the nonplanar conformer is energetically favored by about 1.8 kJ mol(-1) in this model. Since molecular mechanics calculations predict three conformers of Ni(TPP) in solution, we also consider a three-state model. The three structures are two nonplanar structures of purely ruffled (ruf) and purely saddled (sad) macrocyclic distortions and a planar conformer. In the calculations, the ruf conformation is the lowest-energy structure with the planar and sad conformers having almost equal higher energies. Assuming this relationship between the energies, but allowing the actual energy separation to vary, the three-state analysis gives the similar result that the ruf conformation is stabilized by about 2.3 kJ mol(-1) with respect to the planar and sad conformers. C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. UNIV BREMEN,FB1,INST PHYS EXPT,D-28334 BREMEN,GERMANY. UNIV NOTRE DAME,DEPT CHEM & BIOCHEM,NOTRE DAME,IN 46556. RP Jentzen, W (reprint author), SANDIA NATL LABS,CATALYSIS & CHEM TECHNOL DEPT,POB 5800,ALBUQUERQUE,NM 87185, USA. RI Shelnutt, John/A-9987-2009 OI Shelnutt, John/0000-0001-7368-582X NR 49 TC 50 Z9 51 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD AUG 7 PY 1997 VL 101 IS 32 BP 5789 EP 5798 DI 10.1021/jp970496f PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP915 UT WOS:A1997XP91500012 ER PT J AU Smith, RS Huang, C Kay, BD AF Smith, RS Huang, C Kay, BD TI Evidence for molecular translational diffusion during the crystallization of amorphous solid water SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article; Proceedings Paper CT Symposium on Physics and Chemistry of Ice 1996 CY AUG 27-31, 1996 CL HANOVER, NH ID SUPERCOOLED WATER; GLASS-TRANSITION; ASTROPHYSICAL IMPLICATIONS; ICE; STILL; H2O AB Molecular diffusion in amorphous solid water is studied by measuring the extent of isotope exchange and mixing in vapor-deposited ultrathin films using temperature-programmed desorption. Our results indicate there is long-range translational diffusion that occurs concomitantly with the amorphous to crystalline ice phase transition. The apparent diffusivity estimated from these data is a factor of 10(6+/-1) greater than an Arrhenius extrapolation for diffusion in crystalline ice. This finding suggests that the amorphous material exhibits liquid-like translational diffusion prior to crystallization at temperatures near 155 K. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. RI Smith, Scott/G-2310-2015 OI Smith, Scott/0000-0002-7145-1963 NR 29 TC 78 Z9 79 U1 1 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 7 PY 1997 VL 101 IS 32 BP 6123 EP 6126 DI 10.1021/jp963278f PG 4 WC Chemistry, Physical SC Chemistry GA XP913 UT WOS:A1997XP91300012 ER PT J AU Kimmel, GA Orlando, TM Cloutier, P Sanche, L AF Kimmel, GA Orlando, TM Cloutier, P Sanche, L TI Low-energy (5-40 eV) electron-stimulated desorption of atomic hydrogen and metastable emission from amorphous ice SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article; Proceedings Paper CT Symposium on Physics and Chemistry of Ice 1996 CY AUG 27-31, 1996 CL HANOVER, NH ID DISSOCIATIVE EXCITATION; MOLECULAR-HYDROGEN; WATER; IMPACT; DISTRIBUTIONS; SPECTROSCOPY; H2O; D2O; GAS AB Low-energy (5-40 eV) electron-stimulated desorption (ESD) of D (1 S-2) from amorphous D2O water films has been studied using laser resonance-enhanced multiphoton ionization spectroscopy. The D (1 S-2) desorption product has a similar to 6.5 +/- 0.3 eV threshold energy, relative to the vacuum level, and a low velocity distribution. ESD of electronically excited D (n greater than or equal to 2 S-2) was not detected using photoionization schemes. A small metastable (n greater than or equal to 2 P-2) desorption yield and/or emission of ultraviolet (UV) photons (hv greater than or equal to similar to 6 eV) was detected at incident electron energies >25 eV, using a multichannel plate detection technique. We attribute the ground state D desorption to exciton decay and associate the small metastable/UV photon emission yield with dissociation of doubly excited states and efficient autoionization. C1 PACIFIC NW NATL LAB,ENVIRONM MOL SCI LAB,RICHLAND,WA 99352. UNIV SHERBROOKE,FAC MED,MRC,GRP RADIAT SCI,SHERBROOKE,PQ J1H 5N4,CANADA. NR 26 TC 39 Z9 39 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 7 PY 1997 VL 101 IS 32 BP 6301 EP 6303 DI 10.1021/jp9632091 PG 3 WC Chemistry, Physical SC Chemistry GA XP913 UT WOS:A1997XP91300055 ER PT J AU Farrar, CR James, GH AF Farrar, CR James, GH TI System identification from ambient vibration measurements on a bridge SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID GOLDEN-GATE BRIDGE; BOSPORUS SUSPENSION BRIDGE; EXCITATION AB The cross-correlation function between two response measurements made on an ambiently excited structure is shown to have the same form as the system's impulse response function. Therefore, standard time domain curve-fitting procedures, which are typically applied to impulse response functions, can now be applied to the cross-correlation functions to estimate the resonant frequencies and modal damping of the structure. This derivation is based on the assumption that the ambient vibration source is a white noise random process. Curve-fitting cross-correlation functions to obtain modal properties offers advantages over standard procedures that identify resonant frequencies from peaks in the power spectrum and damping from the width of the power spectrum. The primary advantage is the ability to identify closely spaced modes and their associated damping. The resonant frequencies of a highway bridge that were identified by curve-fitting the cross-correlation functions, using traffic excitation as the ambient vibration source, are compared to modal properties identified by standard forced vibration testing methods. Results of this comparison showed a maximum discrepancy of 3.63 percent. Similar comparisons for the average modal damping values identified by the two methods showed a 9.82 percent difference. This experimental verification implies that the proposed method of analyzing ambient vibration data can be used to accurately assess the dynamic properties of structures in a non-intrusive manner. (C) 1997 Academic Press Limited. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Farrar, CR (reprint author), LOS ALAMOS NATL LAB,MS P946,POB 1663,LOS ALAMOS,NM 87545, USA. RI Farrar, Charles/C-6954-2012 NR 43 TC 137 Z9 159 U1 2 U2 20 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD AUG 7 PY 1997 VL 205 IS 1 BP 1 EP 18 DI 10.1006/jsvi.1997.0977 PG 18 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA XQ879 UT WOS:A1997XQ87900001 ER PT J AU Norby, R AF Norby, R TI Carbon cycle - Inside the black box SO NATURE LA English DT Editorial Material RP Norby, R (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,BLDG 1059,POB 2008,OAK RIDGE,TN 37831, USA. NR 6 TC 6 Z9 10 U1 4 U2 10 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD AUG 7 PY 1997 VL 388 IS 6642 BP 522 EP 523 DI 10.1038/41441 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XP722 UT WOS:A1997XP72200024 ER PT J AU Kadlec, RP Zelicoff, AP Vrtis, AM AF Kadlec, RP Zelicoff, AP Vrtis, AM TI Biological weapons control - Prospects and implications for the future SO JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION LA English DT Editorial Material AB The Biological and Toxin Weapons Convention (BWC), which prohibits the acquisition of biological materials for hostile purposes and armed conflict, entered into force in 1975 and now has the participation of 140 nations (158 nations have signed the BWC, but only 140 of these have also ratified it). However, there is no monitoring mechanism associated with the BWC. Diplomatic efforts are now under way to create a supplemental, legally binding protocol to strengthen the convention. Measures to strengthen the BWC are analogous to the diagnostic processes familiar to physicians; the problem facing negotiators is to identify procedures with high positive and negative predictive value. Few proposed measures meet these criteria. However, the investigation of unusual disease outbreaks and allegations of use are highly diagnostic of illicit activities while avoiding false-positive accusations. At the same time, such information generated by the BWC can contribute to worldwide efforts to improve public health, control emergent disease, and establish an international norm against biological weapons proliferation. C1 OFF SECRETARY DEF,WASHINGTON,DC. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. MALCOM GROW MED CTR,DEPT ANESTHESIOL,ANDREWS AFB,MD. NR 27 TC 50 Z9 51 U1 2 U2 3 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 SN 0098-7484 J9 JAMA-J AM MED ASSOC JI JAMA-J. Am. Med. Assoc. PD AUG 6 PY 1997 VL 278 IS 5 BP 351 EP 356 DI 10.1001/jama.278.5.351 PG 6 WC Medicine, General & Internal SC General & Internal Medicine GA XN518 UT WOS:A1997XN51800001 PM 9244311 ER PT J AU Dai, Q Vurens, G Luna, M Salmeron, M AF Dai, Q Vurens, G Luna, M Salmeron, M TI Lubricant distribution on hard disk surfaces: Effect of humidity and terminal group reactivity SO LANGMUIR LA English DT Article ID FORCE MICROSCOPY; WATER; FILMS AB We report studies of the effect of humidity and the chemical nature of the molecular end groups on the structure and spatial distribution of perfluorinated lubricants on hard carbon substrates. The studies are performed with a noncontact atomic force microscopy (AFM) technique that is capable of providing nanometer scale images of soft and liquid surfaces. Our results indicate that reactive end groups enhance the wear resistivity of the lubricants. ZDOL and ZDLAC. which have CH2OH and COOH end groups, respectively, could not be displaced by a sharp tip (approximate to 500 Angstrom radius) under a load of 1 x 10(-8) N while, under the same conditions, Z03, which has CF3 groups at both ends, and Demnum SA, which has a CF3 group and a CH2OH group at each end, could be easily displaced. We found that humidity enhances the mobility of the lubricants. Humidity also causes dramatic changes in the state of aggregation of ZDIAC and Demnum SA. The binding of these lubricants to the surface becomes unstable, and upon contact with the tip, they dewet the surface to form solid-like or liquid-like agglomerates. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. STORMEDIA INC,DEPT RES & DEV,SANTA CLARA,CA 95050. UNIV AUTONOMA MADRID,DEPT FIS MAT CONDENSADA,E-28049 MADRID,SPAIN. RI Luna, Monica/M-1792-2014 OI Luna, Monica/0000-0002-7104-0726 NR 14 TC 24 Z9 24 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD AUG 6 PY 1997 VL 13 IS 16 BP 4401 EP 4406 DI 10.1021/la970323h PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XP793 UT WOS:A1997XP79300034 ER PT J AU Truex, MJ Peyton, BM Valentine, NB Gorby, YA AF Truex, MJ Peyton, BM Valentine, NB Gorby, YA TI Kinetics of U(VI) reduction by a dissimilatory Fe(III)-reducing bacterium under non-growth conditions SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE uranium; kinetics; precipitation; Shewanella; metal reduction ID SHEWANELLA-PUTREFACIENS MR-1; URANIUM; MANGANESE(IV); IRON(III); IRON AB Dissimilatory metal-reducing microorganisms may be useful in processes designed for selective removal of uranium from aqueous streams. These bacteria can use U(VI) as an electron acceptor and thereby reduce soluble U(VI) to insoluble U(IV). While significant research has been devoted to demonstrating and describing the mechanism of dissimilatory metal reduction, the reaction kinetics necessary to apply this for remediation processes have not been adequately defined. In this study, pure culture Shewanella alga strain BrY reduced U(VI) under non-growth conditions in the presence of excess lactate as the electron donor. Initial U(VI) concentrations ranged from 13 to 1680 mu M. A maximum specific U(VI) reduction rate of 2.37 mu mole-U(Vl)/(mg-biomass h) and Monod half-saturation coefficient of 132 mu M-U(VI) were calculated from measured U(VI) reduction rates. U(VI) reduction activity was sustained at 60% of this rate for at least 80 h. The initial presence of oxygen at a concentration equal to atmospheric saturation at 22 degrees C delays but does not prevent U(VI) reduction. The rate of U(VI) reduction by BrY is comparable or better than rates reported for other metal reducing species. BrY reduces U(VI) at a rate that is 30% of its Fe(III) reduction rate. (C) 1997 John Wiley & Sons, Inc. RP Truex, MJ (reprint author), PACIFIC NW LAB, POB 999, MS P7-41, RICHLAND, WA 99352 USA. OI Peyton, Brent/0000-0003-0033-0651 NR 19 TC 65 Z9 67 U1 0 U2 13 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD AUG 5 PY 1997 VL 55 IS 3 BP 490 EP 496 DI 10.1002/(SICI)1097-0290(19970805)55:3<490::AID-BIT4>3.0.CO;2-7 PG 7 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA XH865 UT WOS:A1997XH86500004 PM 18636514 ER PT J AU Tawa, GJ Martin, RL Pratt, LR AF Tawa, GJ Martin, RL Pratt, LR TI Reaction field spectral shifts with semiempirical molecular orbital theory SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Review ID SOLUTE ELECTRONIC-STRUCTURE; POLARIZABLE CONTINUUM MODEL; CLASSICAL SOLVENT DYNAMICS; NONEQUILIBRIUM SOLVATION; AQUEOUS-SOLUTION; FREE-ENERGIES; TAUTOMERIC EQUILIBRIA; GAS-PHASE; ELECTROSTATIC POTENTIALS; NEUTRAL MOLECULES AB A macroscopic solution polarization free-energy functional is combined with semiempirical molecular orbital theory to study shifts of electronic absorption energies for several molecules in solution. The present method requires calculation of the induced electrostatic potential on the van der Waals surface and this calculation is implemented in a new way. The combined method is tested by calculating absorption energy shifts for several molecules of standard interest. We find the physically reasonable result that there is a correlation between the absorption energy shift and the magnitude of the dipole moments of the initial and final states involved in the absorption transition. (C) 1997 John Wiley & Sons, Inc. C1 LOS ALAMOS NATL LAB, DIV THEORET, MS B268, LOS ALAMOS, NM 87545 USA. RP NCI, STRUCT BIOCHEM PROGRAM, FREDERICK BIOMED SUPERCOMP CTR, SAIC, FREDERICK CANC RES & DEV CTR, FREDERICK, MD 21702 USA. RI Pratt, Lawrence/H-7955-2012 OI Pratt, Lawrence/0000-0003-2351-7451 NR 109 TC 11 Z9 11 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0020-7608 EI 1097-461X J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD AUG 5 PY 1997 VL 64 IS 2 BP 143 EP 155 DI 10.1002/(SICI)1097-461X(1997)64:2<143::AID-QUA1>3.0.CO;2-W PG 13 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA XM678 UT WOS:A1997XM67800001 ER PT J AU Zhu, ZL Espenson, JH AF Zhu, ZL Espenson, JH TI Organometallic catalysis: Formation of 1,3-dioxolanes and their analogs catalyzed by methylrhenium trioxide (MTO) SO ORGANOMETALLICS LA English DT Article ID MAIN-GROUP ELEMENTS; TRANSITION-METALS; MULTIPLE BONDS; HYDROGEN-PEROXIDE; CARBONYL-COMPOUNDS; OLEFIN METATHESIS; METHYLTRIOXORHENIUM; OXIDATION; ACETALS; OXIDES AB Methylrhenium trioxide (MTO) catalyzes several cycloaddition reactions. 1,3-Dioxolanes were obtained in good yields from the reactions of epoxides with aldehydes or ketones; the geometric configuration of the epoxide substituents remains unchanged in the product, which was shown to be the consequence of two configuration inversions in sequence. The independently known bis(alkoxy)rhenium complex formed from MTO and the epoxide is an intermediate that could be detected at a low level during the reaction; indeed, its formation limits the rate of the overall reaction. Related cycloaddition reactions are the formation of ketene acetals from diphenylketene and epoxides and of oxazolidines from aromatic imines and epoxides, both MTO-catalyzed. C1 IOWA STATE UNIV,AMES LAB,AMES,IA 50011. IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. NR 37 TC 49 Z9 51 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD AUG 5 PY 1997 VL 16 IS 16 BP 3658 EP 3663 DI 10.1021/om970225r PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA XP426 UT WOS:A1997XP42600018 ER PT J AU Muller, RA MacDonald, GJ AF Muller, RA MacDonald, GJ TI Spectrum of 100-kyr glacial cycle: Orbital inclination, not eccentricity SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT Colloquium on Carbon Dioxide and Climate Change CY NOV 13-15, 1995 CL NATL ACAD SCI, IRVINE, CA HO NATL ACAD SCI ID DEVILS-HOLE; MESOSPHERIC CLOUDS; MILANKOVITCH; CALCITE; RECORD; ORIGIN; OCEAN; VEIN AB Spectral analysis of climate data shows a strong narrow peak with period approximate to 100 kyr, attributed by the Milankovitch theory to changes in the eccentricity of the earth's orbit, The narrowness of the peak does suggest an astronomical origin; however the shape of the peak is incompatible with both linear and nonlinear models that attribute the cycle to eccentricity or (equivalently) to the envelope of the precession, In contrast, the orbital inclination parameter gives a good match to both the spectrum and bispectrum of the climate data, Extraterrestrial accretion from meteoroids or interplanetary dust is proposed as a mechanism that could link inclination to climate, and experimental tests are described that could prove or disprove this hypothesis. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. INT INST APPL SYST ANAL,A-2361 LAXENBURG,AUSTRIA. RP Muller, RA (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 40 TC 30 Z9 31 U1 3 U2 10 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD AUG 5 PY 1997 VL 94 IS 16 BP 8329 EP 8334 DI 10.1073/pnas.94.16.8329 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ124 UT WOS:A1997XQ12400010 PM 11607741 ER PT J AU Herbert, A Alfken, J Kim, YG Mian, IS Nishikura, K Rich, A AF Herbert, A Alfken, J Kim, YG Mian, IS Nishikura, K Rich, A TI A Z-DNA binding domain present in the human editing enzyme, double-stranded RNA adenosine deaminase SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE RNA editing; negative supercoiling; B-Z junction; transcription ID B-Z TRANSITION; CRYSTAL-STRUCTURE; RECEPTOR CHANNELS; CANDIDATE ENZYME; ION FLOW; PROTEIN; COMPLEX; TRANSCRIPTION; DETERMINANTS; PERMEABILITY AB Editing of RNA changes the read-out of information from DNA by altering the nucleotide sequence of a transcript, One type of RNA editing found in all metazoans uses double-stranded RNA (dsRNA) as a substrate and results in the deamination of adenosine to give inosine, which is translated as guanosine, Editing thus allows variant proteins to be produced from a single pre-mRNA, A mechanism by which dsRNA substrates form is through pairing of intronic and exonic sequences before the removal of noncoding sequences by splicing, Here we report that the RNA editing enzyme, human dsRNA adenosine deaminase (DRADA1, or ADAR1) contains a domain (Z alpha) that binds specifically to the left-handed Z-DNA conformation with high affinity (K-D = 4 nM), As formation of Z-DNA in vivo occurs 5' to, or behind, a moving RNA polymerase during transcription, recognition of Z-DNA by DRADA1 provides a plausible mechanism by which DRADA1 can be targeted to a nascent RNA so that editing occurs before splicing, Analysis of sequences related to Z alpha has allowed identification of motifs common to this class of nucleic acid binding domain. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. WISTAR INST ANAT & BIOL,PHILADELPHIA,PA 19104. RP Herbert, A (reprint author), MIT,DEPT BIOL,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. FU NCI NIH HHS [R37 CA004186, 2 R37 CA04186-37]; NIGMS NIH HHS [R01 GM040536, R01 GM40536] NR 64 TC 182 Z9 191 U1 4 U2 9 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD AUG 5 PY 1997 VL 94 IS 16 BP 8421 EP 8426 DI 10.1073/pnas.94.16.8421 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ124 UT WOS:A1997XQ12400025 PM 9237992 ER PT J AU Sobulo, OM Borrow, J Tomek, R Reshmi, S Harden, A Schlegelberger, B Housman, D Doggett, NA Rowley, JD ZeleznikLe, NJ AF Sobulo, OM Borrow, J Tomek, R Reshmi, S Harden, A Schlegelberger, B Housman, D Doggett, NA Rowley, JD ZeleznikLe, NJ TI MLL is fused to CBP, a histone acetyltransferase, in therapy-related acute myeloid leukemia with a t(11;16)(q23;p13.3) SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID 11Q23 CHROMOSOMAL TRANSLOCATIONS; RUBINSTEIN-TAYBI SYNDROME; NUCLEAR-PROTEIN CBP; DROSOPHILA-TRITHORAX; ALL-1 GENE; BAND 11Q23; DOMAIN; IDENTIFICATION; MOTIF; CREB AB The recurring translocation t(11;16)(q23;p13.3) has been documented only in cases of acute leukemia or myelodysplasia secondary to therapy with drugs targeting DNA topoisomerase Il. We show that the MLL gene is fused to the gene that codes for CEP (CREB-binding protein), the protein that binds specifically to the DNA-binding protein CREB (cAMP response element-binding protein) in this translocation. MLL is fused in-frame to a different exon of CBP in two patients producing chimeric proteins containing the AT-hooks, methyltransferase homology domain, and transcriptional repression domain of MLL fused to the CREB binding domain or to the bromodomain of CBP. Both fusion products retain the histone acetyltransferase domain of CBP and may lead to leukemia by promoting histone acetylation of genomic regions targeted by the MLL AT-hooks, leading to transcriptional deregulation via aberrant chromatin organization, CBP is the first partner gene of MLL containing well defined structural and functional motifs that provide unique insights into the potential mechanisms by which these translocations contribute to leukemogenesis. C1 MIT,CTR CANC RES,CAMBRIDGE,MA 02139. CHRISTIAN ALBRECHTS UNIV KIEL,DEPT HUMAN GENET,D-24105 KIEL,GERMANY. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. RP Sobulo, OM (reprint author), UNIV CHICAGO,DEPT MED,HEMATOL ONCOL SECT,CHICAGO,IL 60637, USA. FU NCI NIH HHS [CA17575, CA42557]; NHGRI NIH HHS [HG00299] NR 54 TC 255 Z9 260 U1 0 U2 4 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD AUG 5 PY 1997 VL 94 IS 16 BP 8732 EP 8737 DI 10.1073/pnas.94.16.8732 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ124 UT WOS:A1997XQ12400079 PM 9238046 ER PT J AU Moon, JS Simmons, JA Reno, JL AF Moon, JS Simmons, JA Reno, JL TI Higher order magnetoresistance commensurability oscillations in low aspect ratio antidot lattice and focusing structures SO APPLIED PHYSICS LETTERS LA English DT Article ID POINT CONTACTS; ELECTRON; MAGNETOTRANSPORT; HETEROSTRUCTURES; ORBITS AB We observe unusually strong magnetoresistance commensurability oscillations in two different types of artificial arrays of scattering centers, multiparallel focusing slits and a square antidot lattice, both fabricated on a two-dimensional electron gas by electron-beam lithography and damageless wet etching. The strength of the magnetoresistance peaks is attributed to a high reflection specularity and a small effective antidot cross section. The absence of commensurability effects near Landau level filling factor upsilon=3/2 is attributed to the composite fermion mean free path being smaller than the slit and antidot spacings. The mechanism far the observed commensurability is discussed. (C) 1997 American Institute of Physics. RP Moon, JS (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 4 PY 1997 VL 71 IS 5 BP 656 EP 658 DI 10.1063/1.119820 PG 3 WC Physics, Applied SC Physics GA XN677 UT WOS:A1997XN67700032 ER PT J AU Zhang, SB Zunger, A AF Zhang, SB Zunger, A TI Surface-reconstruction-enhanced solubility of N, P, As, and Sb in III-V semiconductors SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING TUNNELING MICROSCOPY; ALLOYS AB We show that surface reconstructions may play an essential role in determining the equilibrium solubilities of N, P, As, and Sb in various m-V compounds. In particular, anion-anion dimerization of the (001)-beta 2(2 X 4) surface can enhance the solubility of N near the surface in GaAs, GaP, and InP by five, three, and two orders of magnitudes, respectively, at 1000 K. With certain assumptions on the growth kinetics, this high concentration of N may be frozen in as the crystal grows. (C) 1997 American Institute of Physics. RP Zhang, SB (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 20 TC 71 Z9 71 U1 1 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 4 PY 1997 VL 71 IS 5 BP 677 EP 679 DI 10.1063/1.119827 PG 3 WC Physics, Applied SC Physics GA XN677 UT WOS:A1997XN67700039 ER PT J AU Guber, KH Spencer, RR Koehler, PE Winters, RR AF Guber, KH Spencer, RR Koehler, PE Winters, RR TI A BaF2 detector system for (n,gamma) cross section measurements at ORELA SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME C1 DENISON UNIV,DEPT PHYS & ASTRON,GRANVILLE,OH 43023. RP Guber, KH (reprint author), OAK RIDGE NATL LAB,DEPT PHYS,POB 2008,MS-6354,OAK RIDGE,TN 37831, USA. NR 5 TC 8 Z9 8 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C254 EP C257 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500050 ER PT J AU Guber, KH Spencer, RR Koehler, PE Winters, RR AF Guber, KH Spencer, RR Koehler, PE Winters, RR TI Measurements of Nd-142,Nd-144(n,gamma) cross sections at ORELA for astrophysical s-process studies SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID NEUTRON-CAPTURE; PROCESS NUCLEOSYNTHESIS; ISOTOPES; STARS C1 DENISON UNIV,DEPT PHYS & ASTRON,GRANVILLE,OH 43023. RP Guber, KH (reprint author), OAK RIDGE NATL LAB,DEPT PHYS,POB 2008,MS-6354,OAK RIDGE,TN 37831, USA. NR 16 TC 1 Z9 1 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C266 EP C269 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500053 ER PT J AU Hale, GM AF Hale, GM TI Extrapolation of alpha+ carbon reaction cross sections to astrophysical energies SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID STELLAR ENERGIES; C-12(ALPHA,GAMMA)O-16; N-16 RP Hale, GM (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,GRP T-2,MSB-243,LOS ALAMOS,NM 87545, USA. NR 14 TC 46 Z9 46 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C177 EP C180 DI 10.1016/S0375-9474(97)00234-0 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500035 ER PT J AU Jaag, S Kappeler, F Koehler, P AF Jaag, S Kappeler, F Koehler, P TI The stellar (n,gamma) cross section of the unstable Cs-135 SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP Jaag, S (reprint author), FORSCHUNGSZENTRUM KARLSRUHE,INST KERNPHYS 3,POSTFACH 3640,D-76021 KARLSRUHE,GERMANY. NR 10 TC 5 Z9 5 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C247 EP C250 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500048 ER PT J AU Ketlerov, VV Goverdovski, AA Khryachkov, VA Mitrofanov, VF Ostapenko, YB Haight, RC Koehler, PE Grimes, SM Smith, RS AF Ketlerov, VV Goverdovski, AA Khryachkov, VA Mitrofanov, VF Ostapenko, YB Haight, RC Koehler, PE Grimes, SM Smith, RS TI Detailed study of double-differential cross-sections for the O-17(n,alpha)C-14 reaction SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM. OHIO UNIV,ATHENS,GA. RP Ketlerov, VV (reprint author), OBNINSK PHYS & POWER ENGN INST,BONDARENKO SQ 1,OBNINSK 249020,KALUGA REGION,RUSSIA. 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 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD AUG 4 PY 1997 VL 621 IS 1-2 BP C243 EP C246 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500047 ER PT J AU Koehler, PE Spencer, RR Winters, RR Guber, KH Harvey, JA Hill, NW Smith, MS AF Koehler, PE Spencer, RR Winters, RR Guber, KH Harvey, JA Hill, NW Smith, MS TI New neutron capture and transmission measurements for Ba-134,Ba-136 at ORELA and their impact on s-process nucleosynthesis calculations SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME C1 DENISON UNIV,DEPT PHYS & ASTRON,GRANVILLE,OH 43023. RP Koehler, PE (reprint author), OAK RIDGE NATL LAB,DIV PHYS,MS-6354,BLDG 6010,OAK RIDGE,TN 37831, USA. NR 11 TC 2 Z9 2 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C258 EP C261 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500051 ER PT J AU Norman, EB Browne, E Chan, YD Goldman, ID Larimer, RM Lesko, KT Nelson, M Wietfeldt, FE Zlimen, I AF Norman, EB Browne, E Chan, YD Goldman, ID Larimer, RM Lesko, KT Nelson, M Wietfeldt, FE Zlimen, I TI On the half-life of Ti-44 SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME RP Norman, EB (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 9 TC 9 Z9 9 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C92 EP C95 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500019 ER PT J AU Rehm, KE Paul, M Roberts, AD Jiang, CL Blumenthal, D Davids, CN DeCrock, P Fischer, SM Gehring, J Henderson, D Lister, CJ Nickles, J Nolen, J Pardo, RC Schiffer, JP Segel, RE Seweryniak, D AF Rehm, KE Paul, M Roberts, AD Jiang, CL Blumenthal, D Davids, CN DeCrock, P Fischer, SM Gehring, J Henderson, D Lister, CJ Nickles, J Nolen, J Pardo, RC Schiffer, JP Segel, RE Seweryniak, D TI The influence of F-18 induced reactions in the hot CNO cycle SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID F-18(P,ALPHA)O-15 REACTION; BEAM C1 HEBREW UNIV JERUSALEM,JERUSALEM,ISRAEL. UNIV WISCONSIN,MADISON,WI. NORTHWESTERN UNIV,EVANSTON,IL. RP Rehm, KE (reprint author), ARGONNE NATL LAB,DIV PHYS,9700 S CASS,ARGONNE,IL 60439, USA. NR 10 TC 0 Z9 0 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C191 EP C194 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500037 ER PT J AU Starrfield, S Truran, JW Wiescher, M Sparks, WM AF Starrfield, S Truran, JW Wiescher, M Sparks, WM TI Nova nucleosynthesis SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID AL-26 PRODUCTION; REACTION-RATES; RP-PROCESS; EXPLOSIONS; OUTBURSTS; NA-22; MASS C1 UNIV CHICAGO,DEPT ASTRON,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556. LOS ALAMOS NATL LAB,XNH,LOS ALAMOS,NM 87545. RP Starrfield, S (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,POB 871504,TEMPE,AZ 85287, USA. NR 16 TC 6 Z9 6 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C495 EP C498 DI 10.1016/S0375-9474(97)00296-0 PG 4 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500097 ER PT J AU Turner, MS AF Turner, MS TI Cosmology 1996 SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID COLD DARK-MATTER; BIG-BANG NUCLEOSYNTHESIS; LARGE-SCALE STRUCTURE; GRAND-UNIFIED THEORIES; INFLATIONARY UNIVERSE; DEUTERIUM ABUNDANCE; TENSOR PERTURBATIONS; BACKGROUND-RADIATION; BARYON DENSITY; CONSTANT C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Turner, MS (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 79 TC 1 Z9 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C522 EP C531 PG 10 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500101 ER PT J AU Weber, F Weigel, MK Glendenning, NK AF Weber, F Weigel, MK Glendenning, NK TI Neutron stars, strange pulsars and strange dwarfs SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID QUARK-SHELL MODEL; DENSE WHITE-DWARFS; SUPER-HYPERNUCLEI; PHASES C1 UNIV MUNICH, MUNICH, GERMANY. UNIV MUNICH, MUNICH, GERMANY. LAWRENCE BERKELEY LAB, BERKELEY, CA USA. NR 16 TC 0 Z9 0 U1 1 U2 2 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C385 EP C387 PG 3 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500077 ER PT J AU Woosley, SE Hoffman, RD Timmes, FX Weaver, TA Thielemann, FK AF Woosley, SE Hoffman, RD Timmes, FX Weaver, TA Thielemann, FK TI Nucleosynthesis in massive stars and supernovae SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Nuclei in the Cosmos CY JUN 20-27, 1996 CL UNIV NOTRE DAME, NOTRE DAME, IN HO UNIV NOTRE DAME ID THERMONUCLEAR REACTION-RATES; O-18(ALPHA,GAMMA)NE-22; CARBON; OXYGEN; YIELDS; MODELS C1 CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. LAWRENCE LIVERMORE NATL LAB,GEN STUDIES GRP,LIVERMORE,CA 94550. UNIV BASEL,INST THEORET PHYS,CH-4056 BASEL,SWITZERLAND. RP Woosley, SE (reprint author), UNIV CALIF SANTA CRUZ,BOARD STUDIES ASTRON & ASTROPHYS,DEPT ASTRON,SANTA CRUZ,CA 95064, USA. NR 26 TC 11 Z9 11 U1 0 U2 1 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 AUG 4 PY 1997 VL 621 IS 1-2 BP C445 EP C452 PG 8 WC Physics, Nuclear SC Physics GA XU965 UT WOS:A1997XU96500089 ER PT J AU Wei, GW Zhang, DS Kouri, DJ Hoffman, DK AF Wei, GW Zhang, DS Kouri, DJ Hoffman, DK TI Lagrange distributed approximating functionals SO PHYSICAL REVIEW LETTERS LA English DT Article ID EQUATIONS AB Lagrange distributed approximating functionals (LDAFs) are proposed as the basis for a new, collocation-type method for accurately approximating functions and their derivatives both on and off discrete grids. Example applications are presented to illustrate-the use of LDAFs for solving the Schrodinger equation and Fokker-Planck equation. LDAFs are constructed by combining the DAF concept with the Lagrange interpolation scheme. C1 UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV,AMES LAB,AMES,IA 50011. RP Wei, GW (reprint author), UNIV HOUSTON,DEPT CHEM,UNIV PK,HOUSTON,TX 77204, USA. RI Wei, Guowei /E-1852-2011 NR 30 TC 71 Z9 73 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 AUG 4 PY 1997 VL 79 IS 5 BP 775 EP 779 DI 10.1103/PhysRevLett.79.775 PG 5 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900001 ER PT J AU Asner, DM Bliss, DW Brewer, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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, H Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Godang, R Kinoshita, M Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, H Urheim, J Weinstein, AJ Wurthwein, F AF Asner, DM Bliss, DW Brewer, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW 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 Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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, H Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Godang, R Kinoshita, M Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, H Urheim, J Weinstein, AJ Wurthwein, F TI Search for the decays B-0->D(*)D+(*)(-) SO PHYSICAL REVIEW LETTERS LA English DT Article ID LIMIT AB Using the CLEO-II data set we have searched for the decays B-0 --> D-(*+)D-(*-) We observe one candidate signal event for the decay B-0 --> D*+D*- with an expected background of 0.022 +/- 0.011 events. This yield corresponds to a branching fraction of B(B-0 --> D*+D*-) = [5.3(-3.7)(+7.1)(stat)) +/- 1.0(syst)] X 10(-4) and an upper limit of B(B-0 --> D*-D*-) < 2.2 x 10(-3) at the 90% C.L. We see no significant excess of signal above the expected background level in the other modes,,modes, and we calculate the 90% C.L. upper limits on the branching fractions to be B(B-0 --> D*+/-D-/+ < 1.8 X 10(-3) and B(B-0 --> D+D-) < 1.2 X 10(-3). C1 UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. INST PARTICLE PHYS,MONTREAL,PQ,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. RP Asner, DM (reprint author), UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093, USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016; OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587; Bean, Alice/0000-0001-5967-8674; Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900 NR 8 TC 5 Z9 5 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 AUG 4 PY 1997 VL 79 IS 5 BP 799 EP 803 DI 10.1103/PhysRevLett.79.799 PG 5 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900007 ER PT J AU Abe, K Abe, K Akagi, T Allen, NJ Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Baranko, G Bardon, O Barklow, TL Bashindzhagyan, GL Bazarko, AO BenDavid, R Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolen, B Bolton, T Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Busza, W Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A CavalliSforza, M Chou, A Church, E Cohn, HO Coller, JA Cook, V Cotton, R Cowan, RF Coyne, DG Crawford, G DOliveira, A Damerell, CJS Daoudi, M DeSangro, R DellOrso, R Dervan, PJ Dima, M Dong, DN Du, PYC Dubois, R Eisenstein, BI Elia, R Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Frey, R Furuno, K Gillman, T Gladding, G Gonzalez, S Hart, EL Harton, JL Hasan, A Hasegawa, Y Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Hwang, H Iwasaki, Y Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kang, HJ Karliner, I Kawahara, H Kendall, HW Kim, YD King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Labs, JF Langston, M Lath, A Lauber, JA Leith, DWGS Lia, V Liu, MX Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, C Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Messner, R Mockett, PX Moffeit, KC Moore, TB Muller, D Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Ohnishi, Y Onoprienko, D Osborne, LS Panvini, RS Park, CH Park, H Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Stamer, P Steiner, H Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Torrence, E Trandafir, AI Turk, JD Usher, T Vavra, J Vannini, C Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, DL Wagner, SR Waite, AP Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, DA Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Woods, M Word, GB Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J AF Abe, K Abe, K Akagi, T Allen, NJ Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Baranko, G Bardon, O Barklow, TL Bashindzhagyan, GL Bazarko, AO BenDavid, R Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolen, B Bolton, T Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Busza, W Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A CavalliSforza, M Chou, A Church, E Cohn, HO Coller, JA Cook, V Cotton, R Cowan, RF Coyne, DG Crawford, G DOliveira, A Damerell, CJS Daoudi, M DeSangro, R DellOrso, R Dervan, PJ Dima, M Dong, DN Du, PYC Dubois, R Eisenstein, BI Elia, R Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Frey, R Furuno, K Gillman, T Gladding, G Gonzalez, S Hart, EL Harton, JL Hasan, A Hasegawa, Y Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Hwang, H Iwasaki, Y Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kang, HJ Karliner, I Kawahara, H Kendall, HW Kim, YD King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Labs, JF Langston, M Lath, A Lauber, JA Leith, DWGS Lia, V Liu, MX Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, C Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Messner, R Mockett, PX Moffeit, KC Moore, TB Muller, D Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Ohnishi, Y Onoprienko, D Osborne, LS Panvini, RS Park, CH Park, H Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Stamer, P Steiner, H Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Torrence, E Trandafir, AI Turk, JD Usher, T Vavra, J Vannini, C Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, DL Wagner, SR Waite, AP Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, DA Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Woods, M Word, GB Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J TI Direct measurement of leptonic coupling asymmetries with polarized Z bosons SO PHYSICAL REVIEW LETTERS LA English DT Article AB We present direct measurements of the Z(0)-lepton coupling asymmetry parameters A(e), A(mu), and A(tau), based on a data sample of 12063 leptonic Z(0) decays collected by the SLD detector. The Z bosons are produced in collisions of beams of polarized e(-) with unpolarized e(+) at the SLAG Linear Collider. The couplings are extracted from the measurement of the left-right and forward-backward asymmetries for each lepton species, The results are A(e) = 0.152 +/- 0.012(stat) +/- 0,.001(syst), A(mu) 0.102 +/- 0.034 +/- 0.002, and A(tau) = 0.195 +/- 0.034 +/- 0.003. C1 ADELPHI UNIV, GARDEN CITY, NY 11530 USA. IST NAZL FIS NUCL, I-40126 BOLOGNA, ITALY. BOSTON UNIV, BOSTON, MA 02215 USA. BRUNEL UNIV, UXBRIDGE UB8 3PH, MIDDX, ENGLAND. UNIV CALIF SANTA BARBARA, SANTA BARBARA, CA 93106 USA. UNIV CALIF SANTA CRUZ, SANTA CRUZ, CA 95064 USA. UNIV CINCINNATI, CINCINNATI, OH 45221 USA. COLORADO STATE UNIV, FT COLLINS, CO 80523 USA. UNIV COLORADO, BOULDER, CO 80309 USA. COLUMBIA UNIV, NEW YORK, NY 10027 USA. UNIV FERRARA, I-44100 FERRARA, ITALY. IST NAZL FIS NUCL, I-44100 FERRARA, ITALY. IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY. UNIV ILLINOIS, URBANA, IL 61801 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. MIT, CAMBRIDGE, MA 02139 USA. UNIV MASSACHUSETTS, AMHERST, MA 01003 USA. UNIV MISSISSIPPI, UNIVERSITY, MS 38677 USA. MOSCOW MV LOMONOSOV STATE UNIV, INST NUCL PHYS, MOSCOW 119899, RUSSIA. UNIV OREGON, EUGENE, OR 97403 USA. IST NAZL FIS NUCL, I-35100 PADUA, ITALY. UNIV PADUA, I-35100 PADUA, ITALY. IST NAZL FIS NUCL, I-06100 PERUGIA, ITALY. UNIV PERUGIA, I-06100 PERUGIA, ITALY. IST NAZL FIS NUCL, I-56100 PISA, ITALY. UNIV PISA, I-56100 PISA, ITALY. RUTGERS STATE UNIV, PISCATAWAY, NJ 08855 USA. RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. SOONGSIL UNIV, SEOUL 156743, SOUTH KOREA. STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. UNIV TENNESSEE, KNOXVILLE, TN 37996 USA. TOHOKU UNIV, SENDAI, MIYAGI 980, JAPAN. VANDERBILT UNIV, NASHVILLE, TN 37235 USA. UNIV WASHINGTON, SEATTLE, WA 98195 USA. UNIV WISCONSIN, MADISON, WI 53706 USA. YALE UNIV, NEW HAVEN, CT 06511 USA. RP Abe, K (reprint author), NAGOYA UNIV, CHIKUSA KU, NAGOYA, AICHI 464, JAPAN. RI de Sangro, Riccardo/J-2901-2012; Cavalli-Sforza, Matteo/H-7102-2015; Calcaterra, Alessandro/P-5260-2015; Frey, Raymond/E-2830-2016; OI de Sangro, Riccardo/0000-0002-3808-5455; Calcaterra, Alessandro/0000-0003-2670-4826; Frey, Raymond/0000-0003-0341-2636; pieroni, enrico/0000-0002-4246-6963; Wyss, Jeffery/0000-0002-8277-4012 NR 10 TC 16 Z9 16 U1 0 U2 2 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 AUG 4 PY 1997 VL 79 IS 5 BP 804 EP 808 DI 10.1103/PhysRevLett.79.804 PG 5 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900008 ER PT J AU Ginocchio, JN Leviatan, A AF Ginocchio, JN Leviatan, A TI Magnetic dipole sum rules for odd-mass nuclei SO PHYSICAL REVIEW LETTERS LA English DT Article ID DEFORMED-NUCLEI; SCISSORS STATES; E2 STRENGTH; MODEL; M1 AB Sun rules the total- and scissors-model M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to Er-167 and Dy-161. We find consistency with the former measurements but not with the latter. C1 HEBREW UNIV JERUSALEM, RACAH INST PHYS, IL-91904 JERUSALEM, ISRAEL. EUROPEAN CTR THEORET STUDIES NUCL PHYS & RELATED, I-38050 VILLAZANO, TRENTO, ITALY. RP Ginocchio, JN (reprint author), LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. NR 25 TC 14 Z9 14 U1 0 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 AUG 4 PY 1997 VL 79 IS 5 BP 813 EP 816 DI 10.1103/PhysRevLett.79.813 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900010 ER PT J AU Hsi, WC Kwiatkowski, K Wang, G Bracken, DS Cornell, E Ginger, DS Viola, VE Yoder, NR Korteling, RG GimenoNogures, F Ramakrishnan, E Rowland, D Yennello, SJ Huang, MJ Lynch, WG Tsang, MB Xi, H Chu, YY Gushue, S Remsberg, LP Morley, KB Breuer, H AF Hsi, WC Kwiatkowski, K Wang, G Bracken, DS Cornell, E Ginger, DS Viola, VE Yoder, NR Korteling, RG GimenoNogures, F Ramakrishnan, E Rowland, D Yennello, SJ Huang, MJ Lynch, WG Tsang, MB Xi, H Chu, YY Gushue, S Remsberg, LP Morley, KB Breuer, H TI Formation of hot nuclei with GeV p and pi(-) beams SO PHYSICAL REVIEW LETTERS LA English DT Article ID AU-197 REACTIONS; COLLISIONS; MULTIFRAGMENTATION; FRAGMENTATION AB 4 pi studies of multiple charged-particle emission in GeV pi(-)- and proton-induced reactions on a Au target have been performed with the ISIS detector array. distributions yield nearly identical results for both p and pi(-) beams, suggesting an independence of hadron type in initiating the fast cascade and subsequent energy deposition in the struck nucleus. The excitation functions show little sensitivity to beam momentum, consistent with a saturation in deposition energy and the concept of limiting fragmentation. However, the intermediate mass fragment multiplicities and fragment charge distributions depend strongly on collision violence. C1 INDIANA UNIV, IUCF, BLOOMINGTON, IN 47405 USA. SIMON FRASER UNIV, DEPT CHEM, BURNABY, BC V5A 1S6, CANADA. TEXAS A&M UNIV, DEPT CHEM, COLLEGE STN, TX 77843 USA. TEXAS A&M UNIV, INST CYCLOTRON, COLLEGE STN, TX 77843 USA. MICHIGAN STATE UNIV, DEPT PHYS, E LANSING, MI 48824 USA. MICHIGAN STATE UNIV, NATL SUPERCONDUCTING CYCLOTRON LAB, E LANSING, MI 48824 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. UNIV MARYLAND, DEPT PHYS, COLLEGE PK, MD 20742 USA. RP INDIANA UNIV, DEPT CHEM, BLOOMINGTON, IN 47405 USA. RI Ginger, David/C-4866-2011; Lynch, William/I-1447-2013; Rowland, Douglas/F-3104-2014; Yennello, Sherry/B-5803-2015 OI Ginger, David/0000-0002-9759-5447; Lynch, William/0000-0003-4503-176X; Rowland, Douglas/0000-0001-8059-6905; Yennello, Sherry/0000-0003-3963-5217 NR 27 TC 23 Z9 23 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 AUG 4 PY 1997 VL 79 IS 5 BP 817 EP 820 DI 10.1103/PhysRevLett.79.817 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900011 ER PT J AU Kim, JS Fonck, RJ Durst, RD Fernandez, E Terry, PW Paul, SF Zarnstorff, MC AF Kim, JS Fonck, RJ Durst, RD Fernandez, E Terry, PW Paul, SF Zarnstorff, MC TI Measurements of nonlinear energy transfer in turbulence in the Tokamak Fusion Test Reactor SO PHYSICAL REVIEW LETTERS LA English DT Article ID TFTR TOKAMAK; DENSITY TURBULENCE; TRANSPORT; DYNAMICS; CONFINEMENT; TRANSITION; PLASMAS; MODE AB The application of anew bispectral analysis technique to density fluctuation measurements in the core of the Tokamak Fusion Test Reactor indicates that the peak in the autopower spectrum usually lies in a region of linear stability. Large changes in the linear and nonlinear characteristics of the turbulence are observed as the plasma toroidal rotation and/or confinement properties are varied, while estimates of the turbulence-driven diffusivity varies only slightly with rotation. These observations are consistent with the operation of a global organizing property that may be related to the observation of Bohm-like scaling of ion thermal transport. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Kim, JS (reprint author), UNIV WISCONSIN,DEPT NUCL ENGN & ENGN PHYS,MADISON,WI 53706, USA. NR 20 TC 41 Z9 41 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 AUG 4 PY 1997 VL 79 IS 5 BP 841 EP 844 DI 10.1103/PhysRevLett.79.841 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900017 ER PT J AU Boettcher, S Paczuski, M AF Boettcher, S Paczuski, M TI Aging in a model of self-organized criticality SO PHYSICAL REVIEW LETTERS LA English DT Article ID ULTRAMETRIC SPACES; DYNAMICS; RELAXATION; ERGODICITY; DIFFUSION; GLASSES AB Temporal autocorrelation functions for avalanches in the Bak-Sneppen model display aging behavior similar to glassy systems. Numerical simulations show that they decay as power laws with two distinct regimes separated by a time scale which, is the waiting time, or age, of the avalanche. Thus, time-translational invariance is dynamically broken. The critical exponent of the initial decay is that of the familiar stationary dynamics while a new critical exponent for the late-time behavior appears. This new exponent characterizes a nonstationary regime that has not been previously considered in the context of self-organized criticality. C1 UNIV OKLAHOMA,DEPT PHYS & ASTRON,NORMAN,OK 73019. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. RP Boettcher, S (reprint author), CLARK ATLANTA UNIV,CTR THEORET STUDIES PHYS SYST,ATLANTA,GA 30314, USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 41 TC 36 Z9 37 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 AUG 4 PY 1997 VL 79 IS 5 BP 889 EP 892 DI 10.1103/PhysRevLett.79.889 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900029 ER PT J AU Smith, RS Huang, C Wong, EKL Kay, BD AF Smith, RS Huang, C Wong, EKL Kay, BD TI The molecular volcano: Abrupt CCl4 desorption driven by the crystallization of amorphous solid water SO PHYSICAL REVIEW LETTERS LA English DT Article ID ASTROPHYSICAL IMPLICATIONS; SUPERCOOLED WATER; GLASS-TRANSITION; ICE; LIQUIDS; ENTROPY; STILL; H2O AB The desorption kinetics of molecular beam deposited ultrathin films of CCl4 and amorphous solid water (ASW) are studied. Overlayers of ASW impede CCl4 desorption until the onset of crystallization, whereupon the CCl4 desorbs abruptly. The abrupt desorption occurs through connected pathways that are formed in the water overlayer during the nucleation and growth of crystalline ice from ASW. The onset of the abrupt desorption corresponds to the threshold for dynamic percolation. As the crystallization proceeds, the number of connected pathways rapidly increases, giving rise to the episodic release of CCl4. C1 PACIFIC NW NATL LAB,ENVIRONM MOL SCI LAB,RICHLAND,WA 99352. RI Smith, Scott/G-2310-2015 OI Smith, Scott/0000-0002-7145-1963 NR 26 TC 156 Z9 156 U1 0 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 AUG 4 PY 1997 VL 79 IS 5 BP 909 EP 912 DI 10.1103/PhysRevLett.79.909 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900034 ER PT J AU Fultz, B Ahn, CC Alp, EE Sturhahn, W Toellner, TS AF Fultz, B Ahn, CC Alp, EE Sturhahn, W Toellner, TS TI Phonons in nanocrystalline Fe-57 SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEAR RESONANT SCATTERING; MOSSBAUER-SPECTROSCOPY; INTRINSIC INSTABILITY; GRAIN-BOUNDARIES; IRON; PARTICLE; METALS; STATES AB We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear gamma-ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Q(u), averaging about 5, but the longitudinal modes may have been broadened most. The nanocrystalline Fe also shows an enhancement in its phonon DOS at energies below 15 meV. The difference in vibrational entropy of the bulk and nanocrystalline Fe was small, owing to competing changes in the nanocrystalline phonon DOS at low and high energies. C1 ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439. RP Fultz, B (reprint author), CALTECH,DIV ENGN & APPL SCI,PASADENA,CA 91125, USA. NR 25 TC 112 Z9 114 U1 1 U2 11 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 AUG 4 PY 1997 VL 79 IS 5 BP 937 EP 940 DI 10.1103/PhysRevLett.79.937 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900041 ER PT J AU Ozolins, V Wolverton, C Zunger, A AF Ozolins, V Wolverton, C Zunger, A TI Anomalous temperature dependence of the X-ray diffuse scattering intensity of Cu3Au SO PHYSICAL REVIEW LETTERS LA English DT Article RP Ozolins, V (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Wolverton, Christopher/B-7542-2009; Ozolins, Vidvuds/D-4578-2009; Zunger, Alex/A-6733-2013 NR 2 TC 13 Z9 13 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 AUG 4 PY 1997 VL 79 IS 5 BP 955 EP 955 PG 1 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900046 ER PT J AU McMullan, RK Koetzle, TF Fritchie, CJ AF McMullan, RK Koetzle, TF Fritchie, CJ TI Low-temperature neutron diffraction study of the silver perchlorate-benzene pi complex SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID CRYSTAL-STRUCTURE AB The crystal structure of the AgClO4 . C6H6 pi complex, earlier determined by X-ray diffraction at room temperature, has been redetermined at 18, 78 and 158 K by neutron diffraction. Crystal data: orthorhombic, space group Cmcm, Z=4, F(000) = 225.318 fm, T = 18, 17, 158 K; D-x = 2.591 (2), 2.570 (1), 2.523 (1) g cm(-1); mu(n) = 0.166, 0.165, 0.162 cm(-1); a = 7.913 (1), 7.973 (1), 8.100 (1), 8.336(1) Angstrom (at 295 K); b = 7.837(2) , 7.857 (1), 7.902 (1), 7.996 (1) Angstrom (at 295 K); c = 11.798 (3), 11.777 (2), 11.739 (2), 11.638 (2) Angstrom (at 295 K); wR(F-2) = 0.037, 0.035, 0.045, S = 1.18, 1.08, 1.10 for 782, 628, 800 reflections and 51 variable parameters. This study confirms the principal features reported in the X-ray investigation and reveals details of structure not observable at room temperature. Distortions of the benzene molecule from D-6h symmetry ascribed to Ag+... C6H6 interactions are small, but significant. At 18 K the two C-C bonds complexed by Ag+ are 1.405 (1) Angstrom in length; the other four are 1.398 (1) Angstrom. The C-H bonds are equal in length at 1.087 (2) (two) and 1.089 (1) Angstrom (four). The H atoms nearest to Ag+ are displaced 0.064 (1) Angstrom from the C-6 plane, away from the silver. The shortest Ag+... C distance of the complex is 2.565 (1) Angstrom. This value and bond lengths of the benzene molecule are invariant between 18 and 158 K within 2 e.s.d.'s or less. The nonequivalent bond lengths of ClO4-, 1.451 (1) (two) and 1.441 (1) Angstrom (two) at 18 K, are foreshortened by -0.007 and -0.005 Angstrom at 158 K by effects of thermal motion. The O-Cl-O angles, 109.08 (7), 109.98 (2) and 107.83(8)degrees at 18 K, are virtually unchanged by temperature. The Ag+... ClO4- interactions occur at Ag+... O distances of 2.785 (1) and 2.612 (1) Angstrom (18 K), where the shorter values involve ClO4- acting as a bidentate group. Rigid-body and riding-motion models do not adequately account for the observed temperature dependence of bond lengths in ClO4- nor provide significant corrections to the C6H6 bond lengths at 18, 78 and 158 K beyond their uncertainty limits. A harmonic potential rationalizes the motion of Ag+ at these three temperatures. C1 TULANE UNIV,DEPT CHEM,NEW ORLEANS,LA 70118. RP McMullan, RK (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 44 TC 19 Z9 20 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Commun. PD AUG 1 PY 1997 VL 53 BP 645 EP 653 DI 10.1107/S0108768197000712 PN 4 PG 9 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA XQ678 UT WOS:A1997XQ67800009 ER PT J AU Henshall, GA Subramanian, PR Strum, MJ Mendiratta, MG AF Henshall, GA Subramanian, PR Strum, MJ Mendiratta, MG TI Continuum predictions of deformation in composites with two creeping phases .2. Nb5Si3/Nb composites SO ACTA MATERIALIA LA English DT Article AB The primary and steady-state creep behavior of ductile-phase toughened Nb5Si3/Nb in situ composites has been simulated using the analytical and finite element (FE) continuum techniques described in Part I of this paper. The material constants in the creep constitutive law have been fitted to experimentally measured creep properties of the bulk Nb5Si3 and Nb solid-solution phases. The composite microstructure has been idealized to facilitate the modeling, with a variety of microstructural idealizations resulting in very similar predicted composite creep rates. The models somewhat underpredict the steady-state strain rates and over predict the primary creep strains for the Nb-10 at.% Si composite studied experimentally. Several potential causes for these discrepancies have been identified, including internal damage effects and a possible increase in the Nb5Si3 stress exponent at high stress. However, the models correctly make the important prediction that the creep strength of the Nb-rich composite is dominated by the strong Nb5Si3 phase. FE predictions of large internal tensile stresses in the matrix are consistent with experimental observations of creep damage. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. UNIVERSAL ENERGY SYST INC, DAYTON, OH 45432 USA. NR 17 TC 7 Z9 7 U1 0 U2 4 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 AUG PY 1997 VL 45 IS 8 BP 3135 EP 3142 DI 10.1016/S1359-6454(97)00009-8 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XP072 UT WOS:A1997XP07200006 ER PT J AU Sanchez, JC Murr, LE Staudhammer, KP AF Sanchez, JC Murr, LE Staudhammer, KP TI Effect of grain size and pressure on twinning and microbanding in oblique shock loading of copper rods SO ACTA MATERIALIA LA English DT Article ID DYNAMIC RECRYSTALLIZATION; PLASTIC-DEFORMATION; SHAPED CHARGES; MICROSTRUCTURES; BEHAVIOR; STRAIN; ALLOYS AB High-purity copper rods in a range of grain sizes - 29 mu m, 141 mu m and 375 mu m - were shock loaded in an oblique, cylindrical shock fixture which simultaneously and linearly strained the rods from zero to 5% at peak pressures calculated to range from 11 to 30 GPa at the top and bottom of the rods, respectively. These pressures correspond to the minimum and maximum shock deformation. Light metallography and transmission electron microscopy revealed that the density of deformation twins was measurably and observably increased with both increasing grain size and deformation (pressure). In addition, microbands coincident with traces oi {111} planes were observed to be intermixed with the deformation twins. The microbands were almost exclusively associated with a single (or primary) {111} glide plane. The tendency for microband formation, isolated or intermixed with twins, was qualitatively observed to increase with increasing grain size. There appears to be a direct, shear-related connection between microbands and deformation twin/twin-faults in oblique shock loaded copper. The obliquity of the shock wave seems to suppress the critical twinning pressure of copper. since twinning was observed at pressures of only 11 GPa at the top of the rods in contrast to an established critical twinning pressure of approximately 20 GPa for plane-wave shock loading of copper. (C) 1997 Acta Metallurgica Inc. C1 LOS ALAMOS NATL LAB,MST DIV,LOS ALAMOS,NM 87545. RP Sanchez, JC (reprint author), UNIV TEXAS,DEPT MET & MAT ENGN,EL PASO,TX 79968, USA. OI Murr, Lawrence/0000-0001-5942-8376 NR 38 TC 43 Z9 43 U1 3 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD AUG PY 1997 VL 45 IS 8 BP 3223 EP 3235 DI 10.1016/S1359-6454(97)00018-9 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XP072 UT WOS:A1997XP07200013 ER PT J AU McGraw, R AF McGraw, R TI Description of aerosol dynamics by the quadrature method of moments SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID SIZE DISTRIBUTION; PARTICLE-SIZE; CONDENSATION; NUCLEATION; GROWTH AB The method of moments (MOM) may be used to determine the evolution of the lower-order moments of an unknown aerosol distribution. Previous applications of the method have been limited by the requirement that the equations governing the evolution of the lower-order moments be in closed form. Here a new approach, the quadrature method of moments (QMOM), is described. The dynamical equations for moment evolution are replaced by a quadrature-based approximate set that satisfies closure under a much broader range of conditions without requiring that the size distribution or growth law maintain any special mathematical form. The conventional MOM is recovered as a special case of the QMOM under those conditions, e.g., free-molecular growth, for which conventional closure is satisfied. The QMOM is illustrated for the growth of sulfuric acid-water aerosols and simulations of diffusion-controlled cloud droplet growth are presented. (C) 1997 American Association for Aerosol Research. RP McGraw, R (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,ENVIRONM CHEM DIV,UPTON,NY 11973, USA. NR 14 TC 515 Z9 530 U1 4 U2 54 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD AUG PY 1997 VL 27 IS 2 BP 255 EP 265 DI 10.1080/02786829708965471 PG 11 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XM797 UT WOS:A1997XM79700012 ER PT J AU Farkas, T Sepaniak, MJ Guiochon, G AF Farkas, T Sepaniak, MJ Guiochon, G TI Radial distribution of the flow velocity, efficiency and concentration in a wide HPLC column SO AICHE JOURNAL LA English DT Article ID AXIAL-COMPRESSION COLUMNS; LIQUID-CHROMATOGRAPHY; PREPARATIVE CHROMATOGRAPHY; DISPERSION AB The use of optical fibers in a fluorescence-detection scheme permits the accurate determination of the radial distribution of the transit time, the column efficiency, and the analyte concentration at the exit of a chromatographic axial-compression column (50 mmID). The results obtained demonstrate that the column is not homogeneous, but suggest a nearly cylindrical distribution of the packing density. The average velocity close to the column wall is 7% lower than along its axis and the HETP 25% higher. The lack of homogeneity of the column packing is another source of band broadening not taken into account in chromatography so far It causes the apparent HETP derived from the conventional elution chromatogram recorded on the bulk eluent to be larger than the local HETP and the band profile to be unsymmetrical with a slight fail reminiscent of kinetic tailing. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. NR 39 TC 65 Z9 65 U1 1 U2 2 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD AUG PY 1997 VL 43 IS 8 BP 1964 EP 1974 DI 10.1002/aic.690430806 PG 11 WC Engineering, Chemical SC Engineering GA XP957 UT WOS:A1997XP95700005 ER PT J AU Perl, ML Lee, ER AF Perl, ML Lee, ER TI The search for elementary particles with fractional electric charge and the philosophy of speculative experiments SO AMERICAN JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1996 Meeting of the American-Physics-Society CY 1996 CL INDIANAPOLIS, IN SP Amer Phys Soc ID MATTER AB All known elementary particles that can be isolated as individual particles have an electric charge that is equal in magnitude to the electron's charge, q = 1.6 x 10(-19) C, or Is zero. This includes the muon and tau charged leptons, the neutrinos, the photon, the nucleons, and the mesons. There haste been many searches without confirmed success for isolated particles with fractional electric charge such as +/-q/3, or +/-q/2, or +/-3q/2. The theory of the physics of elementary particles does not require the existence of such particles. In particular, current theory holds that quarks, whose charge is +/- (1/3)q or +/- 2/3q, cannot be isolated. Despite past failures and current theory, we have been engaged for the past few years in a new search for isolated elementary particles with fractional electric charge. In the course of this paper we discuss models for fractional charge particles, summarize previous searches, and describe our experimental method; and because this is speculative research we will also present our thoughts on speculative experiments. (C) 1997 American Association Physics Teachers. RP Perl, ML (reprint author), STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. NR 26 TC 23 Z9 23 U1 2 U2 6 PU AMER ASSOC PHYSICS TEACHERS AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD AUG PY 1997 VL 65 IS 8 BP 698 EP 706 DI 10.1119/1.18641 PG 9 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA XM906 UT WOS:A1997XM90600010 ER PT J AU May, D Howard, J AF May, D Howard, J TI Coconut crab. Kwajalein atoll, Republic of the Marshall Islands (vol 168, pg 1500, 1997) SO AMERICAN JOURNAL OF ROENTGENOLOGY LA English DT Correction, Addition C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. RP May, D (reprint author), USAF,LACKLAND AFB,TX 78236, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU AMER ROENTGEN RAY SOC PI RESTON PA 1891 PRESTON WHITE DR, SUBSCRIPTION FULFILLMENT, RESTON, VA 22091 SN 0361-803X J9 AM J ROENTGENOL JI Am. J. Roentgenol. PD AUG PY 1997 VL 169 IS 2 BP 602 EP 602 PG 1 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA XM758 UT WOS:A1997XM75800079 ER PT J AU Guschin, D Yershov, G Zaslavsky, A Gemmell, A Shick, V Proudnikov, D Arenkov, P Mirzabekov, A AF Guschin, D Yershov, G Zaslavsky, A Gemmell, A Shick, V Proudnikov, D Arenkov, P Mirzabekov, A TI Manual manufacturing of oligonucleotide, DNA, and protein microchips SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID HYBRIDIZATION; ARRAYS AB A simple procedure for manufacturing microchips containing various gel-immobilized compounds is described. A gel photopolymerization technique is introduced to produce micromatrices of polyacrylamide gel pads (25 x 25 x 20 mu m and larger) separated by a hydrophobic glass surface. A pin device for the manual application of a compound in solution onto the activated polyacrylamide gel pad for immobilization is described. Oligonucleotide, DNA, and protein microchips have been produced by this method and tested by hybridization and immunoanalysis monitored with a fluorescence microscope, The effect of the lengths of the immobilized oligonucleotides and the hybridized RNA and DNA on hybridization of the oligonucleotide microchips was evaluated. This method can also be used for manufacturing microchips containing a variety of other compounds. (C) 1997 Academic Press. C1 ARGONNE NATL LAB,JOINT HUMAN GENOME PROGRAM,ARGONNE,IL 60439. VA ENGELHARDT MOL BIOL INST,JOINT HUMAN GENOME PROGRAM,MOSCOW 117984,RUSSIA. NR 26 TC 195 Z9 213 U1 0 U2 14 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD AUG 1 PY 1997 VL 250 IS 2 BP 203 EP 211 DI 10.1006/abio.1997.2209 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA XM801 UT WOS:A1997XM80100012 PM 9245440 ER PT J AU BarPeled, M Raikhel, NV AF BarPeled, M Raikhel, NV TI An efficient method for cloning in-frame fusion protein genes SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID ESCHERICHIA-COLI C1 MICHIGAN STATE UNIV,MSU DOE PLANT RES LAB,E LANSING,MI 48824. NR 3 TC 2 Z9 2 U1 1 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD AUG 1 PY 1997 VL 250 IS 2 BP 262 EP 264 DI 10.1006/abio.1997.2237 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA XM801 UT WOS:A1997XM80100023 PM 9245451 ER PT J AU Klunder, GL Andrews, JE Grant, PM Andresen, BD Russo, RE AF Klunder, GL Andrews, JE Grant, PM Andresen, BD Russo, RE TI Analysis of fission products using capillary electrophoresis with on-line radioactivity detection SO ANALYTICAL CHEMISTRY LA English DT Article ID ISOTACHOPHORESIS-ZONE ELECTROPHORESIS; METAL-IONS; RADIOISOTOPE DETECTION; RADIONUCLIDE DETECTION; SEPARATION; CHROMATOGRAPHY; SENSITIVITY AB Capillary electrophoresis has been used to separate metal ions characteristically associated with nuclear fission. Indirect UV absorbance and on-line radioactivity detection were used simultaneously to monitor the analytes, The radioactivity detector consists of conical plastic scintillating material with the capillary passing through the center to provide a 4 pi detection geometry. The wide end of the cone is optically coupled to a photomultiplier tube, Transient isotachophoretic techniques were employed to stack large volumes of samples which had low specific activities. Radioactivity detection of Eu-152, and Cs-137 was achieved at the nanocurie level for 80-100 nL injections. The detector is approximately 80% efficient enabling samples resident in the detector window for 0.1 min to be reliably assayed. The separation of Cs-137 and Ba-137m isotopes, which are in secular equilibrium, was modeled to demonstrate the effects of the rapid decay of Ba-137m. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Klunder, GL (reprint author), LAWRENCE LIVERMORE NATL LAB,FORENS SCI CTR,POB 808,L-371,LIVERMORE,CA 94550, USA. NR 27 TC 11 Z9 12 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD AUG 1 PY 1997 VL 69 IS 15 BP 2988 EP 2993 DI 10.1021/ac970042e PG 6 WC Chemistry, Analytical SC Chemistry GA XN424 UT WOS:A1997XN42400027 PM 21639319 ER PT J AU Dietz, ML Chiarizia, R Horwitz, EP Bartsch, RA Talanov, V AF Dietz, ML Chiarizia, R Horwitz, EP Bartsch, RA Talanov, V TI Effect of crown ethers on the ion-exchange behavior of alkaline earth metals. Toward improved lon exchange methods for the separation and preconcentration of radium SO ANALYTICAL CHEMISTRY LA English DT Article ID EXTRACTION CHROMATOGRAPHY; SOLVENT-EXTRACTION; SILICA-GEL; MACROCYCLE INTERACTION; KINETIC DATA; STRONTIUM; CATIONS; RESIN; SIZE; TVEX-DCH18C6 AB The effect of selected crown ethers on the uptake of alkaline earth cations by sulfonic acid and diphosphonic acid-based cation-exchange resins from hydrochloric acid media is examined. The effect observed is shown to vary with the hydrophobicity of the crown ether, Water-soluble crown ethers enhance the sorption of certain cations, thereby improving the selectivity of the resin for other alkaline earths over calcium ion, an apparent result of a synergistic interaction between crown ether present in the resin phase and the ionic functional groups of the resin. In the presence of more hydrophobic crown ethers, a decrease in cation sorption is often observed, a result of the exclusion of the crown ether from the resin phase and the formation of cation-crown complexes in the solution phase, The result can be a reversal of the selectivity sequence ordinarily exhibited by the resin. C1 TEXAS TECH UNIV,DEPT CHEM & BIOCHEM,LUBBOCK,TX 79409. RP Dietz, ML (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 61 TC 26 Z9 26 U1 3 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD AUG 1 PY 1997 VL 69 IS 15 BP 3028 EP 3037 DI 10.1021/ac9700437 PG 10 WC Chemistry, Analytical SC Chemistry GA XN424 UT WOS:A1997XN42400033 PM 21639322 ER PT J AU Bredesen, DE Ellerby, LM Hart, PJ WiedauPazos, M Valentine, JS AF Bredesen, DE Ellerby, LM Hart, PJ WiedauPazos, M Valentine, JS TI Do posttranslational modifications of CuZnSOD lead to sporadic amyotrophic lateral sclerosis? SO ANNALS OF NEUROLOGY LA English DT Editorial Material ID CU/ZN SUPEROXIDE-DISMUTASE; OXIDATIVE MODIFICATION; FRAGMENTATION; INACTIVATION; MUTATIONS; GLYCATION; PROGRAM; GENE; MICE C1 UNIV CALIF LOS ANGELES,US DOE,LAB STRUCT BIOL & MOL MED,LOS ANGELES,CA. UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024. RP Bredesen, DE (reprint author), BURNHAM INST,PROGRAM AGING,10901 N TORREY PINES RD,LA JOLLA,CA 92037, USA. RI Valentine, Joan/B-6665-2008 OI Valentine, Joan/0000-0002-7174-925X NR 25 TC 27 Z9 27 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0364-5134 J9 ANN NEUROL JI Ann. Neurol. PD AUG PY 1997 VL 42 IS 2 BP 135 EP 137 DI 10.1002/ana.410420202 PG 3 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA XQ524 UT WOS:A1997XQ52400001 PM 9266721 ER PT J AU Turso, JA MarchLeuba, J Edwards, RM AF Turso, JA MarchLeuba, J Edwards, RM TI A modal-based reduced-order model of BWR out-of-phase instabilities SO ANNALS OF NUCLEAR ENERGY LA English DT Article AB A low-order model of BWR out-of-phase instabilities is developed via modal analysis. The modal point kinetics equations are derived using the fundamental and first harmonic modes of the neutron diffusion equation. Parameter estimation in the frequency domain is used to determine the coefficients of the transfer functions (or differential equations) representing the necessary BWR feedback characteristics. Combined with well-known nonlinear reactor kinetics, the resulting simple structure of the model provides physical insight into the mechanisms behind the out-of-phase coupled thermal-hydraulic/neutronic BWR instability. This investigation is specifically oriented toward the LaSalle Unit II BWR. An out-of-phase simulation of the LaSalle BWR illustrates the ability of these equations to effectively reproduce the phenomenon. (C) 1997 Elsevier Science Ltd. C1 OAK RIDGE NATL LAB,DIV INSTRUMENTAT & CONTROLS,OAK RIDGE,TN 37831. RP Turso, JA (reprint author), PENN STATE UNIV,DEPT NUCL ENGN,231 SACKETT BLDG,UNIVERSITY PK,PA 16802, USA. NR 12 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0306-4549 J9 ANN NUCL ENERGY JI Ann. Nucl. Energy PD AUG PY 1997 VL 24 IS 12 BP 921 EP 934 DI 10.1016/S0306-4549(96)00069-2 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XC106 UT WOS:A1997XC10600001 ER PT J AU Kieft, TL Kovacik, WP Ringelberg, DB White, DC Haldeman, DL Amy, PS Hersman, LE AF Kieft, TL Kovacik, WP Ringelberg, DB White, DC Haldeman, DL Amy, PS Hersman, LE TI Factors limiting microbial growth and activity at a proposed high-level nuclear repository, Yucca mountain, Nevada SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID DEEP SUBSURFACE; HETEROTROPHIC BACTERIA; RADIOACTIVE-WASTE; ROCK; HETEROGENEITY; SEDIMENTS; DISPOSAL; SAMPLES AB As part of the characterization of Yucca Mountain, Nev., as a potential repository for high-level nuclear waste, volcanic tuff was analyzed for microbial abundance and activity. Tuff was collected aseptically from nine sites along a tunnel in Yucca Mountain. Microbial abundance was generally low: direct microscopic cell counts were near detection limits at all sites (3.2 x 10(4) to 2.0 x 10(5) cells g(-1) [dry weight]): plate counts of aerobic heterotrophs ranged from 1.0 x 10(1) to 3.2 x 10(3) CFU g(-1) (dry weight), Phospholipid fatty acid concentrations (0.1 to 3.7 pmol g(-1)) also indicated low microbial biomasses; diglyceride fatty acid concentrations, indicative of dead cells, were in a similar range (0.2 to 2.3 pmol g(-1)). Potential microbial activity was quantified as (CO2)-C-14 production in microcosms containing radiolabeled substrates (glucose, acetate, and glutamic acid); amendments with water and nutrient solutions (N and P) were used to test factors potentially limiting this activity. Similarly, the potential for microbial growth and the factors limiting growth were determined by performing plate counts before and after incubating volcanic tuff samples for 24 h under various conditions: ambient moisture, water-amended, and amended with various nutrient solutions (N, P, and organic C), A high potential for microbial activity was demonstrated by high rates of substrate mineralization (as much as 70% of added organic C in 3 weeks). Water was the major limiting factor to growth and microbial activity, while amendments with N and P resulted in little further stimulation. Organic C amendments stimulated growth more than water alone. C1 UNIV TENNESSEE,CTR ENVIRONM BIOTECHNOL,KNOXVILLE,TN 37932. UNIV NEVADA,DEPT LIFE SCI,LAS VEGAS,NV 89154. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. RP Kieft, TL (reprint author), NEW MEXICO INST MIN & TECHNOL,DEPT BIOL,SOCORRO,NM 87801, USA. NR 35 TC 30 Z9 33 U1 0 U2 7 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD AUG PY 1997 VL 63 IS 8 BP 3128 EP 3133 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA XP067 UT WOS:A1997XP06700026 PM 16535670 ER PT J AU Hyman, JM Li, J AF Hyman, JM Li, J TI Disease transmission models with biased partnership selection SO APPLIED NUMERICAL MATHEMATICS LA English DT Article; Proceedings Paper CT Volterra Centennial at the 2nd International Conference on the Numerical Solution of Volterra and Delay Equations CY MAY 27-30, 1996 CL ARIZONA STATE UNIV, TEMPE, AZ SP Natl Sci Fdn, Arizona State Univ, Vice President Res, Arizona State Univ, Coll Liberal Arts & Sci, Arizona State Univ, Coll Engn, Arizona State Univ, Ctr Syst Sci, Arizona State Univ, Dept Math HO ARIZONA STATE UNIV DE epidemiological models; sexually transmitted disease; selective mixing; reproductive number ID SPREAD; POPULATIONS; EPIDEMIC; AIDS; HIV AB In multi-group epidemiological models with nonrandom mixing between people in the different groups, often artificial constraints have to be imposed in order to satisfy the balance conditions, We present and analyze simple selective mixing models governed by systems of ordinary differential equations, where the balance conditions are automatically satisfied as a natural consequence of the equations, These models can be applied in situations where biased partnership formations among people in different risk, social, economic, ethnic, or geographic groups must be accounted to accurately predict the epidemic, Because in these models the actual number of partners an individual has depends upon the distribution of the population, the threshold conditions are a sensitive function of this distribution. We formulate threshold conditions for the model and analyze the sensitivity of these conditions to different population distributions, to changes in transmission rates and to the biasing in the partnership selection. These conditions were determined by either explicitly defining a Liapunov function or by using the eigenvalues of the Jacobian matrix to calculate a reproductive number. We present numerical examples to illustrate how the reproductive number depends upon the variations in the population and transmission parameters. Published by Elsevier Science B.V. C1 UNIV ALABAMA,DEPT MATH SCI,HUNTSVILLE,AL 35899. RP Hyman, JM (reprint author), LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,THEORET DIV,MS-B284,LOS ALAMOS,NM 87545, USA. NR 21 TC 11 Z9 11 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD AUG PY 1997 VL 24 IS 2-3 BP 379 EP 392 DI 10.1016/S0168-9274(97)00034-2 PG 14 WC Mathematics, Applied SC Mathematics GA XH617 UT WOS:A1997XH61700023 ER PT J AU Enderlein, J Ambrose, WP AF Enderlein, J Ambrose, WP TI Optical collection efficiency function in single-molecule detection experiments SO APPLIED OPTICS LA English DT Article DE single-molecule detection; collection efficiency function; flow cytometry AB The optical collection efficiency function for an optical system such as that used in single-molecule detection experiments is studied. Closed analytical expressions based on a geometrical optics approximation are presented. Comparison is made with exact wave optics calculations. (C) 1997 Optical Society of America. RP Enderlein, J (reprint author), LOS ALAMOS NATL LAB,CST-1,MS M888,LOS ALAMOS,NM 87545, USA. NR 10 TC 10 Z9 10 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 1 PY 1997 VL 36 IS 22 BP 5298 EP 5302 DI 10.1364/AO.36.005298 PG 5 WC Optics SC Optics GA XN683 UT WOS:A1997XN68300003 PM 18259345 ER PT J AU Soufli, R Gullikson, EM AF Soufli, R Gullikson, EM TI Reflectance measurements on clean surfaces for the determination of optical constants of silicon in the extreme ultraviolet-soft-x-ray region SO APPLIED OPTICS LA English DT Article ID PHOTOABSORPTION; ALUMINUM; AL; SI AB The refractive index n = 1 - delta + i beta of Si in the energy range 50-180 eV is investigated with angle-dependent reflectance measurements. The optical constants delta and beta are both determined by fitting to the Fresnel equations. The results of this method are compared with the values in the atomic tables derived from experimental data for beta and implementation of the Kramers-Kronig for relations for delta. The samples were prepared by UV irradiation and HF:ethanol dipping to H passivate the surface. It is found that the values of delta in the atomic tables are 8-15% too high in the region 50-90 eV. This is attributed to missing oscillator strength in the tabulated absorption coefficient for Si. The measured values of beta for crystalline Si exhibit structure below the L-2,L-3 edge (99.8 eV), as was previously observed in transmission measurements of Si(111). It is also found that the method of least-squares fitting reflectance data to obtain optical constants is most effective for energies well below the edge, where delta > beta, while for a range of energies around and above the edge, where delta < beta, the optical constants are determined with large uncertainties. This behavior is not unique to the Si L-2,L-3 edge. (C) 1997 Optical Society of America. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR XRAY OPT,BERKELEY,CA 94720. RP Soufli, R (reprint author), UNIV CALIF BERKELEY,DEPT ELECT ENGN & COMP SCI,BERKELEY,CA 94720, USA. NR 15 TC 66 Z9 67 U1 2 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 1 PY 1997 VL 36 IS 22 BP 5499 EP 5507 DI 10.1364/AO.36.005499 PG 9 WC Optics SC Optics GA XN683 UT WOS:A1997XN68300030 PM 18259372 ER PT J AU Mui, PH Srajer, G Mills, DM AF Mui, PH Srajer, G Mills, DM TI In situ surface monitoring system for synchrotron mirrors under high heat load SO APPLIED OPTICS LA English DT Article DE metrology; thermally induced surface distortion; mirrors AB A portable electro-optical system capable of real-time measurements of surface slope distortions down to 0.5 mu rad is described; the system is limited primarily by its short-term stability. The system employs an angle measurement technique that, in combination with the least-squares signal extraction method, reduces system fluctuations, In addition, a multireflection technique is used to enhance the detectable resolution, Although designed for use with mirrors for synchrotron radiation sources, this system has the flexibility to be applied to other optical components. The prototype system has been tested on a sample mirror piece, and preliminary results are presented. A brief discussion about the extension of this metrology unit to adaptive optics is also given. (C) 1997 optical Society of America. RP Mui, PH (reprint author), ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439, USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 1 PY 1997 VL 36 IS 22 BP 5546 EP 5551 DI 10.1364/AO.36.005546 PG 6 WC Optics SC Optics GA XN683 UT WOS:A1997XN68300036 PM 18259378 ER PT J AU Mourant, JR Bigio, IJ Jack, DA Johnson, TM Miller, HD AF Mourant, JR Bigio, IJ Jack, DA Johnson, TM Miller, HD TI Measuring absorption coefficients in small volumes of highly scattering media: Source-detector separations for which path lengths do not depend on scattering properties SO APPLIED OPTICS LA English DT Article DE absorbance measurements; turbid media; tissue absorption; concentration measurements ID DIFFUSION-THEORY; TISSUE; CHEMOTHERAPY; SPECTROSCOPY; REFLECTANCE; BRAIN AB The noninvasive measurement of variations in absorption that are due to changes in concentrations of biochemically relevant compounds in tissue is important in many clinical settings. One problem with such measurements is that the path length traveled by the collected light through the tissue depends on the scattering properties of the tissue. We demonstrate, using both Monte Carlo simulations and experimental measurements, that for an appropriate separation between light-delivery and light collection fibers the path length of the collected photons does not depend on scattering parameters for the range of parameters typically found in tissue. This is important for developing rapid, noninvasive, and inexpensive methods for measuring absorption changes in tissue. (C) 1997 Optical Society of America. RP Mourant, JR (reprint author), LOS ALAMOS NATL LAB,BIOSCI & BIOTECHNOL GRP,CST-4,MS E535,LOS ALAMOS,NM 87545, USA. NR 15 TC 113 Z9 114 U1 1 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 1 PY 1997 VL 36 IS 22 BP 5655 EP 5661 DI 10.1364/AO.36.005655 PG 7 WC Optics SC Optics GA XN683 UT WOS:A1997XN68300050 PM 18259392 ER PT J AU LawniczakJablonska, K Jia, JJ Lin, L Grush, MM Callcott, TA Asfaw, A Carlisle, JA Terminello, LJ Himpsel, FJ Ederer, DL Underwood, JH Perera, RCC AF LawniczakJablonska, K Jia, JJ Lin, L Grush, MM Callcott, TA Asfaw, A Carlisle, JA Terminello, LJ Himpsel, FJ Ederer, DL Underwood, JH Perera, RCC TI Resonant inelastic scattering in dilute magnetic semiconductors by soft X-ray fluorescence spectroscopy SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT International Workshop on Resonant Inelastic Soft X-Ray Scattering (RIXS) CY SEP 05-07, 1996 CL WALBERBERG, GERMANY ID ALLOYS; ABSORPTION AB Soft X-ray fluorescence (SXF) provides a means of measuring the element and angular momentum selective valence band density of states in complex materials. Recent studies have demonstrated that SXF excited near the absorption threshold generates an array of spectral features that depend on the nature of the material, particularly on the localization of excited states in s- and d-band solids. The current interest in dilute magnetic semiconductors (DMS) remains highly motivated by recent prospective applications, especially in optoelectronics. The Mn and S - L resonant X-ray emission spectra of Zn1-xMnxS (where 0.05 less than or equal to x less than or equal to 1) were measured as the energy of the exciting radiation was tuned across the S and Mn -L-2,L-3 absorption edges of these compounds. Strong resonance peaks in Mn-L emission spectra and the systematic appearance of new spectral features in S-L emission spectra were observed. Partial substitution of Zn by a magnetic Mn ion results in strong hybridization of the Mn 3d orbitals with the sp band of the host semiconductor. A detailed study of resonant inelastic scattering in the vicinity of the S and Mn-L-2,L-3 absorption edges of these DMS is presented. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. UNIV WISCONSIN,MADISON,WI 53589. TULANE UNIV,NEW ORLEANS,LA 70118. RP LawniczakJablonska, K (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Lawniczak-Jablonska, Krystyna/J-8994-2012 OI Lawniczak-Jablonska, Krystyna/0000-0003-1042-570X NR 17 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD AUG PY 1997 VL 65 IS 2 BP 173 EP 177 DI 10.1007/s003390050561 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XQ288 UT WOS:A1997XQ28800015 ER PT J AU Uehara, Y Lindle, DW Callcott, TA Terminello, LT Himpsel, FJ Ederer, DL Underwood, JH Gullikson, EM Perera, RCC AF Uehara, Y Lindle, DW Callcott, TA Terminello, LT Himpsel, FJ Ederer, DL Underwood, JH Gullikson, EM Perera, RCC TI Resonant inelastic scattering at the L edge of Ti in Barium Strontium Titanate by soft X-ray fluorescence spectroscopy SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT International Workshop on Resonant Inelastic Soft X-Ray Scattering (RIXS) CY SEP 05-07, 1996 CL WALBERBERG, GERMANY ID THIN-FILMS AB Photon-excited Ti L fluorescence spectra were measured for cubic barium strontium titanate (BSTO) using tunable synchrotron radiation near the Ti L-edge. Elastic (recombination) peaks were observed around Ti L-3 and L-2 resonances, especially strong at the L-3 resonance, while inelastic peaks were observed from well below the resonance and showed complex features at the excitation energies between the Ti L-3 and L-2 resonances. The measured spectra were explained based on radiative and non-radiative electronic processes near the Ti-L-2,L-3 edge in the titanate. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. UNIV WISCONSIN,CTR SYNCHROTRON RADIAT,STOUGHTON,WI 53589. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Uehara, Y (reprint author), UNIV NEVADA,DEPT CHEM,LAS VEGAS,NV 89154, USA. NR 10 TC 19 Z9 19 U1 1 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD AUG PY 1997 VL 65 IS 2 BP 179 EP 182 DI 10.1007/s003390050562 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XQ288 UT WOS:A1997XQ28800016 ER PT J AU Kopf, D Weingarten, KJ Zhang, G Moser, M Emanuel, MA Beach, RJ Skidmore, JA Keller, U AF Kopf, D Weingarten, KJ Zhang, G Moser, M Emanuel, MA Beach, RJ Skidmore, JA Keller, U TI High-average-power diode-pumped femtosecond Cr:LiSAF lasers SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID TI-SAPPHIRE LASER; PEROT SATURABLE ABSORBER; SOLID-STATE LASERS; MODE-LOCKING; CRLISAF LASER; PULSES; FLUORESCENCE; OPERATION; CRYSTALS; CAVITY AB We achieve 0.5-W and 110-fs pulses from a diode-pumped mode locked Cr:LiSAF laser, pumped by a 1200-times diffraction-limited 0.9-cm-wide 15-W diode-laser array. Pulses as short as 50 fs at 0.34 W are obtained, and a continous-wave output power of 1.42 W. These high-power results are based on an optimized mode-matching technique for good pump beam to cavity mode overlap, combined with a specialized crystal size and cooling geometry. A semiconductor saturable absorber mirror (SESAM) with low insertion loss is used to start and stabilize the mode locking. Using this device has the advantage that the mode locking dynamics are decoupled from the cavity layout, which is important for the design of the high-power resonator. In comparison to this high-power approach, we obtain 125-mW, 60-fs, and 105-mW, 45-fs pulses from a standard diode-pumped femtosecond Cr:LiSAF laser using two 12-times diffraction limited high-brightness 0.5-W, 100-mu m pump diodes. C1 TIME BANDWIDTH PROD AG,CH-8005 ZURICH,SWITZERLAND. PAUL SCHERRER INST,CH-8048 ZURICH,SWITZERLAND. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Kopf, D (reprint author), ETH HONGGERBERG,HPT,SWISS FED INST TECHNOL,INST QUANTUM ELECT,ULTRAFAST LASER PHYS LAB,CH-8093 ZURICH,SWITZERLAND. RI Keller, Ursula/N-2437-2016 OI Keller, Ursula/0000-0002-1689-8041 NR 52 TC 60 Z9 60 U1 1 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD AUG PY 1997 VL 65 IS 2 BP 235 EP 243 DI 10.1007/s003400050269 PG 9 WC Optics; Physics, Applied SC Optics; Physics GA XQ287 UT WOS:A1997XQ28700013 ER PT J AU Renschler, CL Stallard, BR White, CA Garcia, MJ Morse, HE AF Renschler, CL Stallard, BR White, CA Garcia, MJ Morse, HE TI Photodegradation in ballistic laminates: Spectroscopy and lifetime extension SO APPLIED SPECTROSCOPY LA English DT Article DE IR reflectance spectroscopy; photodegradation of polycarbonate; ballistic laminates; transparent armor ID POLYCARBONATE; BISPHENOL AB Polycarbonate (PC), a critical component in ballistic laminates (BLs), is known to degrade upon exposure to ultraviolet (UV) light. For the purpose of reducing the photodegradation, a UV blocking chemical has been added to the adhesives used to join the layers of the BL. This report describes the development of a spectroscopic method for monitoring surface photodegradation of PC and the method's use in demonstrating the effectiveness of the UV blocker. Reports in the literature demonstrate that photodegradation in thin PC films mag be detected by transmission infrared (IR) spectroscopy. The present work extends this approach to thick films, where small surface changes are detected by refit chance IR spectroscopy. We show that UV photodegradation of the PC surface produces a characteristic shift in the carbonyl absorption band at about 1775 cm(-1). This shift is consistently observed in PC samples that have been subjected to direct artificial exposure and in PC samples that have been subjected through the outboard layers of the BL to both natural and artificial exposure. When a UV blocker is incorporated into the adhesive layers of the laminate, no peak shift is observed in the carbonyl band after the equivalent of 10 years of exposure. RP Renschler, CL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 7 TC 2 Z9 2 U1 1 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD AUG PY 1997 VL 51 IS 8 BP 1130 EP 1133 DI 10.1366/0003702971941953 PG 4 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA XU635 UT WOS:A1997XU63500010 ER PT J AU Tan, WH Haydon, PG Yeung, ES AF Tan, WH Haydon, PG Yeung, ES TI Imaging neurotransmitter uptake and depletion in astrocytes SO APPLIED SPECTROSCOPY LA English DT Article DE imaging; native fluorescence; neurotransmitters; single cell ID NATIVE FLUORESCENCE; CELLS; CATECHOLAMINES; AMPEROMETRY; EXOCYTOSIS; JUNCTION; RELEASE; BRAIN AB An ultraviolet (UV) laser-based optical microscope and charge-coupled device (CCD) detection system was used to obtain chemical images of biological cells. Subcellular structures can he easily seen in both optical and fluorescence images. Laser-induced native fluorescence detection provides high sensitivity and low limits of detection, and it does not require coupling to fluorescent dyes. We were able to quantitatively monitor serotonin that has been taken up into and released from individual astrocytes on the basis of its native fluorescence. Different regions of the cells took up different amounts of serotonin with a variety of uptake kinetics. Similarly, we observed different serotonin depletion dynamics in different astrocyte regions. There were also some astrocyte areas where no serotonin uptake or depletion was observed. Potential applications include the mapping of other biogenic species in cells as well as the ability to image their release from specific regions of cells in response to external stimuli. C1 US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT ZOOL & GENET,LAB CELLULAR SIGNALING,AMES,IA 50011. RI Tan, Weihong/A-5412-2008 OI Tan, Weihong/0000-0002-8066-1524 NR 19 TC 16 Z9 16 U1 0 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD AUG PY 1997 VL 51 IS 8 BP 1139 EP 1143 DI 10.1366/0003702971941656 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA XU635 UT WOS:A1997XU63500012 ER PT J AU Figg, D Kahr, MS AF Figg, D Kahr, MS TI Elemental fractionation of glass using laser ablation inductively coupled plasma mass spectrometry SO APPLIED SPECTROSCOPY LA English DT Article DE laser ablation; inductively coupled plasma; mass spectrometry; elemental fractionation; laser focal point signal minimum; irradiance AB Three laser wavelengths (1064, 532, and 266 nm) were employed for laser ablation at varied laser pulse energies to study the effect of irradiance and wavelength upon analytical results for laser ablation inductively coupled plasma mass spectrometry (LP,-ICP-MS). Two important results were observed and are reported here: (1) the intensity of the MS signal came to a local minimum when the laser focal point was on the sample surface, and (2) elemental fractionation based upon laser wavelength and laser pulse energy was observed. For the waste glass simulant studied, ablation with 1064-nm (IR) and 532-nm (green) radiation produced elemental fractionation that relates to the melting point of the elemental oxide, whereas with 266-nm (UV) ablation the response was independent of the elemental oxide melting point. At high laser powers, ablation at 266 nm produced an elemental bias based upon the mass of the elements. These observations suggest the use of ultraviolet radiation at low pulse energies to obtain improved analytical results. RP Figg, D (reprint author), LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,CST9,LOS ALAMOS,NM 87545, USA. NR 23 TC 65 Z9 68 U1 0 U2 3 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD AUG PY 1997 VL 51 IS 8 BP 1185 EP 1192 DI 10.1366/0003702971941728 PG 8 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA XU635 UT WOS:A1997XU63500019 ER PT J AU Thevuthasan, S Shivaparan, NR Smith, RJ Gao, Y Chambers, SA AF Thevuthasan, S Shivaparan, NR Smith, RJ Gao, Y Chambers, SA TI Rutherford backscattering and channeling studies of a TiO2(100) substrate, epitaxially grown pure and Nb-doped TiO2 films SO APPLIED SURFACE SCIENCE LA English DT Article ID ENERGY ION-SCATTERING; PHOTOCATALYTIC ACTIVITY AB We have investigated the crystalline quality of a TiO2(100) substrate, homoepitaxially grown TiO2 film and Nb-doped TiO2 films using Rutherford backscattering (RBS) and channeling experiments. The minimum yields obtained from the aligned and random spectra are 2.4 +/- 0.2% for the TiO2(100) substrate, and 4.0 +/- 0.2% for a homoepitaxial TiO2 film. The minimum yields for Ti and Nb are 1.6 +/- 0.2% and 7.0 +/- 1.0%, respectively, for a Nb-doped TiO2 film. Also, about 95% of the Nb atoms occupy cation sites in the Nb-doped TiO2 film. The angular yield curves for Ti and Nb from the Nb-doped film confirm the good crystalline quality of the film in which most Nb atoms occupy the cation sites. The calculated surface peak areas for Ti and Nb using a model which incorporates Nb surface segregation from the bulk, agree very well with the corresponding surface peak areas for Ti and Nb extracted from the experiment. (C) 1997 Pacific Northwest Laboratories, Battelle. Published by Elsevier Science B.V. C1 MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717. RP Thevuthasan, S (reprint author), PACIFIC NW NATL LAB,ENVIRONM MOL SCI LAB,RICHLAND,WA 99352, USA. NR 15 TC 14 Z9 14 U1 3 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 AUG PY 1997 VL 115 IS 4 BP 381 EP 385 DI 10.1016/S0169-4332(97)00005-6 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA XM010 UT WOS:A1997XM01000011 ER PT J AU Bendicho, PF Bueno, JT Auer, L AF Bendicho, PF Bueno, JT Auer, L TI Multidimensional radiative transfer with multilevel atoms .2. The non-linear multigrid method SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiative transfer; stars, atmospheres; methods, numerical ID LAMBDA ITERATION METHOD; CONTINUUM AB A new iterative method for solving non-LTE multilevel radiative transfer (RT) problems in 1D, 2D or 3D geometries is presented. The scheme obtains the self-consistent solution of the kinetic and RT equations at the cost of only a few (< 10) formal solutions of the RT equation. It combines, for the first time, non-linear multigrid iteration (Brandt, 1977; Hackbush, 1985), an efficient multilevel RT scheme based on Gauss-Seidel iterations (cf. Trujillo Bueno gr Fabiani Bendicho, 1995), and accurate short-characteristics formal solution techniques. By combining a valid stopping criterion with a nested-grid strategy a converged solution with the desired true error is automatically guaranteed. Contrary to the current operator splitting methods the very high convergence speed of the new RT method does not deteriorate when the grid spatial resolution is increased. With this non-linear multigrid method non-LTE problems discretized on N grid points are solved in O(N) operations. The nested multigrid RT method presented here is, thus, particularly attractive in complicated multilevel transfer problems where small grid-sizes are required. The properties of the method are analyzed both analytically and with illustrative multilevel calculations for Ca II in 1D and 2D schematic model atmospheres. C1 INST ASTROFIS CANARIAS, E-38200 LA LAGUNA, TENERIFE, SPAIN. KIEPENHEUER INST SONNENPHYS, D-79104 FREIBURG, GERMANY. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RI Fabiani Bendiccho, Maria de la Pena/C-5684-2017 NR 16 TC 45 Z9 45 U1 1 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 1997 VL 324 IS 1 BP 161 EP 176 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XR029 UT WOS:A1997XR02900017 ER PT J AU Breger, M Handler, G Garrido, R Audard, N Beichbuchner, F Zima, W Paparo, M Jiang, SY Liu, ZL Zhou, AY Pikall, H Stankov, A Guzik, JA Sperl, M Krzesinski, J Ogloza, W Pajdosz, G Zola, S Serkowitsch, E Reegen, P Rumpf, T Schmalwieser, A AF Breger, M Handler, G Garrido, R Audard, N Beichbuchner, F Zima, W Paparo, M Jiang, SY Liu, ZL Zhou, AY Pikall, H Stankov, A Guzik, JA Sperl, M Krzesinski, J Ogloza, W Pajdosz, G Zola, S Serkowitsch, E Reegen, P Rumpf, T Schmalwieser, A TI The variability of a newly discovered gamma Doradus star, HD 108100 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars: variables: other; stars: oscillations; stars: individual: HD 108100; stars: individual: 4 CVn ID PHOTOMETRY AB A coordinated photometric campaign at five observatories to monitor the suspected brightness variations of the early-l; star HD 108100 was undertaken by the DSN (Delta Scuti Network) and WET (Whole Earth Telescope). 288 hours of high-quality observations during a 58 day time span led to the discovery of two frequencies of 1.32 and 1.40 c/d with V amplitudes of 0.010 and 0.007 mag. The detection of both frequencies is statistically significant with amplitude signal/noise ratios of 18 and 12. The light variations are accompanied by v - y color variations of 0.005 and 0.003 mag, respectively. The variability of HD 108100 is typical of the new class of gamma Dor variables. We also derive amplitude ratios and phase differences between the light curves at different wavelengths. These are consistent with g-mode pulsation of l = 1, but not l = 2. The observed periods can be fit by two modes with successive radial orders of n similar to 19, Studies of the delta Scuti star 4 CVn from 1970 to 1976 reported the existence of unusually low frequencies of 1.3 and 1.4 c/d. These frequencies can now be traced back to HD 108100, the single comparison star used in these studies. Consequently, 4 CVn should no longer be regarded as an example of a star exhibiting both delta Scuti type pulsation (acoustic modes of mixed character) and gamma Dor variability (gravity modes of high order). An analysis of unpublished data from 1970 to 1976 shows that the amplitudes associated with the two frequencies of HD 108100 are variable and that the two frequencies can appear to switch their power. C1 INST ASTROFIS ANDALUCIA, E-18080 GRANADA, SPAIN. KONKOLY OBSERV BUDAPEST, H-1525 BUDAPEST 12, HUNGARY. CHINESE ACAD SCI, BEIJING ASTRON OBSERV, BEIJING 100080, PEOPLES R CHINA. LOS ALAMOS NATL LAB, XTA, LOS ALAMOS, NM 87545 USA. CRACOW PEDAGOG UNIV, MT SUHORA OBSER, PL-30084 KRAKOW, POLAND. JAGIELLONIAN UNIV, PL-30244 KRAKOW, POLAND. OBSERV COTE AZUR, CNRS URA 1362, F-06305 NICE 4, FRANCE. RP Breger, M (reprint author), UNIV VIENNA, INST ASTRON, TURKENSCHANZSTR 17, A-1180 VIENNA, AUSTRIA. RI Schmalwieser, Alois/B-3748-2011 OI Schmalwieser, Alois/0000-0003-0719-391X NR 20 TC 37 Z9 38 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 1997 VL 324 IS 2 BP 566 EP 572 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XT419 UT WOS:A1997XT41900023 ER PT J AU Duncan, RC Li, H AF Duncan, RC Li, H TI The halo beaming model for gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxy, halo; gamma rays, bursts; stars, magnetic fields; stars, neutron ID MAGNETIZED NEUTRON-STARS; GALACTIC HALO; RADIO PULSARS; SPACE VELOCITIES; REPEATER 1806-20; FIELD; EVOLUTION; EMISSION; BATSE; IDENTIFICATION AB We consider a model for gamma-ray bursts (GRBs) from high-velocity neutron stars in the Galactic halo. In this model, bursters are born in the Galactic disk with large recoil velocities V-r, and GRBs are beamed to within emission cones of half-angle phi(b) centered on V-r. We describe scenarios for magnetically channeled GRBs that have such beaming characteristics. We then make detailed comparisons of this halo beaming model (HBM) to data from the Third BATSE Catalog and from the Pioneer Venus Orbiter experiment, for both GRB intensity and angular position distributions. Acceptable fits to observations of over 1000 bursts are obtained for phi(b) = 15 degrees-30 degrees and for a BATSE sampling depth of D similar to 180 kpc, which corresponds to a peak burst luminosity of similar to 10(40) ergs s(-1). Present data favor a truly isotropic (cosmological) model over the HBM but not by a statistically compelling margin (less than or similar to 2 sigma). The HBM makes the distinctive prediction that the galactocentric quadrupole moment (cos(2) Theta) -1/3 for bright, nearby GRBs is large, even though the dipole moment [cos Theta] remains near zero. Bursters born in nearby external galaxies, such as M31, are almost entirely undetectable in the HBM because of misdirected beaming. We analyze several refinements of the basic HBM: gamma-ray intensities that vary with angle from the beam axis; non-standard candle GRB luminosity functions; and models including a subset of bursters that do not escape from the Galaxy. We also discuss the energy budgets for the bursters, the origins of their recoils, and the physics of burst beaming and alignment. One possible physical model is based on the magnetar model of soft gamma repeaters (SGRs). Empirical bounds on the rate of formation and peculiar velocities of SGRs imply that there exist similar to 10(4) to similar to 10(7) aged SGRs in the Galactic halo within a distance similar to 100 kpc. The HBM gives an acceptable fit to observations only if it satisfies some special conditions (phi(b) approximate to 20 degrees; uniform bursting rate) that are possible, but for which there are no clear and compelling theoretical justifications. The cosmological burst hypothesis is more generic and thus more attractive in this sense. C1 UNIV TEXAS, MCDONALD OBSERV, AUSTIN, TX 78712 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RP Duncan, RC (reprint author), UNIV TEXAS, DEPT ASTRON, RLM 15308, AUSTIN, TX 78712 USA. NR 136 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1997 VL 484 IS 2 BP 720 EP 740 DI 10.1086/304364 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XP941 UT WOS:A1997XP94100019 ER PT J AU Moran, EC Helfand, DJ AF Moran, EC Helfand, DJ TI The 3-53 keV spectrum of the quasar 1508+5714: X-rays from z=4.3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; quasars, individual (1508+5714); X-rays, galaxies ID HIGH-REDSHIFT QUASARS; ACTIVE GALACTIC NUCLEI; BACKGROUND SPECTRUM; RADIO-LOUD; ASCA; SATELLITE AB We present a high-quality X-ray spectrum in the 3-53 keV rest frame band of the radio-loud quasar 1508+5714, which is by far the brightest known X-ray source at z > 4. A simple power-law model with an absorption column density equal to the Galactic value in the direction of the source provides an excellent and fully adequate fit to the data; the measured power-law photon index Gamma = 1.42(-0.10)(+0.13). Upper limits to Fe K alpha line-emission and Compton-reflection components are derived. We offer evidence for both X-ray and radio variability in this object and provide the first contemporaneous radio spectrum (alpha = -0.25). The data are all consistent with a picture in which the emission from this source is dominated by a relativistically beamed component in both the X-ray and radio bands. C1 COLUMBIA UNIV,DEPT ASTRON,NEW YORK,NY 10027. RP Moran, EC (reprint author), LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,L-413,LIVERMORE,CA 94550, USA. NR 42 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1997 VL 484 IS 2 BP L95 EP L98 DI 10.1086/310787 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XP943 UT WOS:A1997XP94300001 ER PT J AU Yanny, B Jannuzi, BT Impey, C AF Yanny, B Jannuzi, BT Impey, C TI Hubble Space Telescope imaging of the BL Lacertae object OJ 287 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects, individual (OJ 287); galaxies, active; galaxies, jets; galaxies, photometry AB Hubble Space Telescope WFPC-2 I-band (F814W) images of the BL Lacertae object OJ 287 and the surrounding field are presented. We find evidence of associated extended nebulosity near OJ 287, as well as a small nebulosity to the west, which may be spatially coincident with the position of previously observed radio emission. The brightness of a host galaxy is difficult to determine because of the brightness of the active nucleus, but it lies in the range -21.5 > M-R > -23.1 (H-0 = 100 km s(-1) Mpc(-1), q(0) = 0). No evidence is seen for the previously reported optical ''jet'' at position angle 220 degrees to a surface brightness limit of I = 24.3 mag arcsec(-2). There are several resolved and unresolved objects within 17 '' of OJ 287 in the field to limits of I = 25 (point source 5 a detections). The magnitudes and relative positions of these objects are reported, An offset in the centroid position between the OJ 287 point source and the underlying nebulosity reported by Wurtz, Stocke, and Yee is confirmed and measured to be about 0.'' 4 (1.2 h(-1) kpc at the redshift of OJ 287). This offset is tentatively interpreted as evidence for recent merger activity rather than as a sign of gravitational microlensing. C1 NATL OPT ASTRON OBSERV,TUCSON,AZ 85726. UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. RP Yanny, B (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 26 TC 12 Z9 12 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1997 VL 484 IS 2 BP L113 EP & DI 10.1086/310793 PN 2 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XP943 UT WOS:A1997XP94300005 ER PT J AU Reck, RA Weinberg, BL Bornick, RM Wen, GY Frederick, J AF Reck, RA Weinberg, BL Bornick, RM Wen, GY Frederick, J TI New approach to the characterization of long-term changes in total atmospheric ozone: Determination and application of frequency distributions: Reply SO ATMOSPHERIC ENVIRONMENT LA English DT Editorial Material C1 UNIV CHICAGO,DEPT GEOPHYS SCI,CHICAGO,IL 60637. RP Reck, RA (reprint author), ARGONNE NATL LAB,GLOBAL CLIMATE CHANGE PROGRAM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD AUG PY 1997 VL 31 IS 15 BP 2377 EP 2378 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XE531 UT WOS:A1997XE53100022 ER PT J AU Elston, TC Oster, G AF Elston, TC Oster, G TI Protein turbines .1. The bacterial flagellar motor SO BIOPHYSICAL JOURNAL LA English DT Article ID TRYPTOPHAN-SCANNING MUTAGENESIS; ESCHERICHIA-COLI; FLUCTUATION ANALYSIS; ROTATION; TORQUE; MODEL AB The bacterial flagellar motor is driven by a flux of ions between the cytoplasm and the periplasmic lumen. Here we show how an electrostatic mechanism can convert this ion flux into a rotary torque. We demonstrate that, with reasonable parameters, the model can reproduce many of the experimental measurements. C1 UNIV CALIF BERKELEY, DEPT MOL & CELLULAR BIOL, BERKELEY, CA 94720 USA. LOS ALAMOS NATL LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. NR 35 TC 58 Z9 58 U1 0 U2 3 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD AUG PY 1997 VL 73 IS 2 BP 703 EP 721 PG 19 WC Biophysics SC Biophysics GA XM537 UT WOS:A1997XM53700012 PM 9251788 ER PT J AU Reiss, M BarcellosHoff, MH AF Reiss, M BarcellosHoff, MH TI Transforming growth factor-beta in breast cancer: A working hypothesis SO BREAST CANCER RESEARCH AND TREATMENT LA English DT Review DE breast cancer; TGF beta; activation; resistance; receptors; tamoxifen; chemoprevention ID MAMMARY EPITHELIAL-CELLS; SERINE THREONINE KINASE; TUMOR-SUPPRESSOR GENE; RECEPTOR-TYPE-II; EXTRACELLULAR-MATRIX; LUNG-CANCER; MICROSATELLITE INSTABILITY; PLASMINOGEN-ACTIVATOR; ESTROGEN-RECEPTOR; INHIBITOR PAI-1 AB Transforming Growth Factor-beta (TGF beta) is the most potent known inhibitor of the progression of normal mammary epithelial cells through the cell cycle. During the early stages of breast cancer development, the transformed epithelial cells appear to still be sensitive to TGF beta-mediated growth arrest, and TGF beta can act as an anti-tumor promoter. In contrast, advanced breast cancers are mostly refractory to TGF beta-mediated growth inhibition and produce large amounts of TGF beta, which may enhance tumor cell invasion and metastasis by its effects on extracellular matrix. We postulate that this seemingly paradoxical switch in the responsiveness of tumor cells to TGF beta during progression is the consequence of the activation of the latent TGF beta that is produced and deposited into the tumor microenvironment, thereby driving the clonal expansion of TGF beta-resistant tumor cells. While tumor cells themselves may activate TGF beta, recent observations suggest that environmental tumor promoters or carcinogens, such as ionizing radiation, can cause stromal fibroblasts to activate TGF beta by epigenetic mechanisms. As the biological effects of the anti-estrogen tamoxifen may well be mediated by TGF beta, this model has a number of important implications for the clinical uses of tamoxifen in the prevention and treatment of breast cancer. In addition, it suggests a number of novel approaches to the treatment of advanced breast cancer. C1 YALE UNIV, SCH MED, DEPT MED MED ONCOL, NEW HAVEN, CT 06520 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV LIFE SCI, BERKELEY, CA 94720 USA. RI Reiss, Michael/A-8314-2009 FU NCI NIH HHS [CA 51841] NR 118 TC 130 Z9 139 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0167-6806 J9 BREAST CANCER RES TR JI Breast Cancer Res. Treat. PD AUG PY 1997 VL 45 IS 1 BP 81 EP 95 DI 10.1023/A:1005865812918 PG 15 WC Oncology SC Oncology GA XR843 UT WOS:A1997XR84300010 PM 9285120 ER PT J AU Peles, JD Barrett, GW AF Peles, JD Barrett, GW TI Assessment of metal uptake and genetic damage in small mammals inhabiting a fly ash basin SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID RESERVOIR; SCRIPTA C1 UNIV GEORGIA,INST ECOL,ATHENS,GA 30602. RP Peles, JD (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. NR 18 TC 7 Z9 7 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD AUG PY 1997 VL 59 IS 2 BP 279 EP 284 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XH419 UT WOS:A1997XH41900016 PM 9211700 ER PT J AU Taylor, SR Hartse, HE AF Taylor, SR Hartse, HE TI An evaluation of generalized likelihood ratio outlier detection to identification of seismic events in Western China SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article AB The generalized likelihood ratio outlier detection technique for seismic event identification is evaluated using synthetic test data and frequency-dependent P-g/L-g measurements from wester China. For most seismic stations that are to be part of the proposed International Monitoring System (IMS) for the Comprehensive Test Ban Treaty (CTBT), there will be few or no nuclear explosions in the magnitude range of interest (e.g., m(b) < 4) on which to base an event-identification system using traditional classification techniques. Outlier detection is a reasonable alternative approach to the seismic discrimination problem when no calibration explosions are available. Distance-corrected P-g/L-g data in seven different frequency hands ranging from 0.5 to 8 Hz from the Chinese Digital Seismic Station WMQ are used to evaluate the technique. The data are collected from 157 known earthquakes, 215 unknown events (presumed earthquakes and possibly some industrial explosions), and 18 known nuclear explosions (1 from the Chinese Lop Nor test site and 17 from the East Kazakh test site). A feature selection technique is used to find the best combination of discriminants to use for outlier detection. Good discrimination performance is found by combining a low-frequency (0.5 to 1 Hz) P-g/L-g ratio with high-frequency ratios (e.g. 2 to 4 and 4 to 8 Hz). Although the low-frequency ratio does not discriminate between earthquakes and nuclear explosions well by itself, it can be effectively combined with the high-frequency discriminants. Based on the tests with real and synthetic data, the outlier detection technique appears to be an effective approach to seismic monitoring in uncalibrated regions. RP Taylor, SR (reprint author), LOS ALAMOS NATL LAB,DIV EARTH & ENVIRONM SCI,GEOPHYS GRP,EES 3,LOS ALAMOS,NM 87545, USA. NR 7 TC 19 Z9 21 U1 0 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD AUG PY 1997 VL 87 IS 4 BP 824 EP 831 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XT251 UT WOS:A1997XT25100004 ER PT J AU Horton, SP dePolo, DM Walter, WR AF Horton, SP dePolo, DM Walter, WR TI Source parameters and tectonic setting of the 1990 Lee Vining, California, earthquake sequence SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID GREAT-BASIN; EASTERN CALIFORNIA; STRESS DROP; LONG VALLEY; AFTERSHOCKS; PATTERNS; NEVADA AB On 24 October 1990, a magnitude 5.0 (M-d) earthquake occurred near Lee Vining, California. It was a strike-slip event with a hypocenter 5 km east and 11.5 km below the surface trace of the Sierran frontal fault, which at this locality has 21 m of Holocene vertical offset, A time-domain deconvolution technique was used to estimate the source-time function of this event using a small foreshock as an empirical Green's function. The resulting source-time function indicates a simple rupture process, The moment for this event is 3.0 X 10(23) dyne-cm, and the static stress drop is 36 bars, Moderate-sized earthquakes occurring in the western Basin and Range since 1978 have been concentrated in the central part of the Walker Lane Belt, This is an area of diverse topography and numerous strike-slip faults that lies between the Sierra Nevada Mountains on the west and typical Basin and Range topography on the east. Most of these earthquakes have strike-slip focal mechanisms, and with the exception of earthquakes in the Long Valley Caldera area, they are consistent with left-lateral slip on faults that trend northeast and right-lateral slip on faults that trend northwest. C1 UNIV NEVADA,MACKAY SCH MINES,SEISMOL LAB,RENO,NV 89557. LAWRENCE LIVERMORE NATL LAB,DIV EARTH SCI,LIVERMORE,CA 94550. RP Horton, SP (reprint author), COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,POB 1000,PALISADES,NY 10964, USA. RI Walter, William/C-2351-2013 OI Walter, William/0000-0002-0331-0616 NR 30 TC 1 Z9 1 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD AUG PY 1997 VL 87 IS 4 BP 1035 EP 1045 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XT251 UT WOS:A1997XT25100019 ER PT J AU Mezyk, SP Lossack, A Bartels, DM AF Mezyk, SP Lossack, A Bartels, DM TI Rate constants for the reaction of the hydrogen atom with aliphatic ketones in water SO CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE LA English DT Article DE Arrhenius; kinetics; hydrogen atom; aqueous; ketones ID AQUEOUS-SOLUTION; HYDRATED ELECTRONS; EPR MEASUREMENT; RADIOLYSIS; ACCIDENTS; PRODUCTS; RADICALS; IODINE AB Arrhenius parameters for the reaction of hydrogen atoms with 3-methyl-2-butanone, 3-pentanone, cyclopentanone, 4-methyl-2-pentanone, and 2-butanone in aqueous solution have been directly calculated from electron paramagnetic resonance free induction decay (FID) attenuation measurements. For these compounds, absolute scavenging rate constants at 25.0 degrees C of (8.84 +/- 0.26) x 10(7), (4.20 +/- 0.15) x 10(7), (4.91 +/- 0.28) x 10(7), (3.25 +/- 0.27) x 10(7), and (2.20 +/- 0.32) x 10(7) dm(3) mol(-1) s(-1), with corresponding activation energies of 17.43 +/- 0.29, 20.69 +/- 0.31, 18.73 +/- 0.35, 22.24 +/- 0.80, and 22.30 +/- 1.04 kJ mol(-1) were determined, respectively. Competition kinetic measurements based on total H-2 yields have established that for all of these ketones the dominant hydrogen atom reaction path is by H-. atom abstraction. The new activation energy for 2-butanone is much lower than the previously reported value of 40.1 +/- 0.7 kJ mol(-1) with this difference attributed to interfering reactions from the added bromide previously used as a hydroxyl radical scavenger. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. UNIV STUTTGART,INST PHYS CHEM,D-7000 STUTTGART,GERMANY. RP Mezyk, SP (reprint author), ATOM ENERGY CANADA LTD,RES CHEM BRANCH,WHITESHELL LABS,PINAWA,MB R0E 1L0,CANADA. NR 29 TC 5 Z9 5 U1 2 U2 8 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4042 J9 CAN J CHEM JI Can. J. Chem.-Rev. Can. Chim. PD AUG PY 1997 VL 75 IS 8 BP 1114 EP 1119 DI 10.1139/v97-133 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA XX043 UT WOS:A1997XX04300009 ER PT J AU Duff, MC Amrhein, C Bradford, G AF Duff, MC Amrhein, C Bradford, G TI Nature of uranium contamination in the agricultural drainage water evaporation ponds of the San Joaquin Valley, California, USA SO CANADIAN JOURNAL OF SOIL SCIENCE LA English DT Article DE uranium; salinity; redox potential; carbonate alkalinity; bioaccumulation; algae ID HEAVY-METAL ELEMENTS; CHLORELLA-REGULARIS; BIOLOGICAL-SYSTEMS; SALINE WATERS; REDUCTION; ACCUMULATION; ION AB Evaporation ponds used for agricultural subsurface drainage water disposal in the Tulare Lake Bed (TLB) of the San Joaquin Valley, California, USA, have elevated levels of U. Waterfowl which inhabit and forage the ponds and surrounding areas are threatened by exposure to U. The ponds, which receive irrigation drainage waters and seasonal rain, are subject to wetting and drying periods. The periods result in the accumulation of decaying algae and other organic material in surface sediments. Sediment and waters in the ponds were sampled to determine what factors control U solubility and sediment U concentrations. Data from a 1990 study conducted by Chilcott et al. in 1989 on the TLB ponds were used to help identify what factors may control U solubility. Pond sediment U concentrations decreased abruptly with depth and surface sediment U concentrations were related to dissolved Ca:HCO3 ratios. Pond algal U bioaccumulation was favored in waters with high Ca:HCO3 ratios, which had lower pH values and carbonate alkalinities than waters with low Ca:HCO3 ratios. Ponds with high salinities and high carbonate alkalinities contained the highest aqueous U concentrations relative to other TLB ponds. Sediment total organic carbon (TOC) was correlated with sediment U concentrations, suggesting that U is bound to organic matter. The source of TOC is most likely from algae deposition. C1 UNIV CALIF RIVERSIDE,DEPT SOIL & ENVIRONM SCI,RIVERSIDE,CA 92521. RP Duff, MC (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,POB 1663,MS J534,LOS ALAMOS,NM 87545, USA. NR 33 TC 10 Z9 10 U1 1 U2 6 PU AGR INST CANADA PI OTTAWA PA SUITE 907 151 SLATER ST, OTTAWA ON K1P 5H4, CANADA SN 0008-4271 J9 CAN J SOIL SCI JI Can. J. Soil Sci. PD AUG PY 1997 VL 77 IS 3 BP 459 EP 467 PG 9 WC Soil Science SC Agriculture GA YC095 UT WOS:A1997YC09500015 ER PT J AU Artioli, G Pavese, A Stahl, K McMullan, RK AF Artioli, G Pavese, A Stahl, K McMullan, RK TI Single-crystal neutron-diffraction study of pyrope in the temperature range 30-1173 K SO CANADIAN MINERALOGIST LA English DT Article DE pyrope; neutron diffraction; anharmonicity; crystal structure; Dora Maira massif; Italy ID MIXING PROPERTIES; SYNTHETIC PYROPE; WESTERN ALPS; GARNETS; THERMODYNAMICS; SPECTROSCOPY; CHEMISTRY; SILICATES; MINERALS; COESITE AB Single-crystal neutron-diffraction data were collected over the temperature range 30-1173 K on a pyrope crystal from the Dora Maira Massif, Western Alps, Italy. The study expands the structure analysis of synthetic end-member pyrope previously performed with X-ray single-crystal diffraction over a wide temperature range. The neutron nuclear scattering allows a more accurate definition of the atomic displacement parameters and their temperature dependence. The problems involved in the characterization of the atomic displacement parameters in garnet minerals, and especially in pyrope, have implication for the correct interpretation of the physical and thermodynamic properties of the garnet structure. The present analysis of the atomic displacement properties by the higher cumulants model in the Gram-Charlier series approximation shows that the anharmonic contribution to the dynamic part of the magnesium site displacement is significant above 700 K. No evidence is found for static site disorder in the dodecahedral Mg site by refinement with split-atom models, and the intercept at 0 K resulting from linear interpolation of the high-temperature harmonic displacement coefficients is not statistically significant. The refinement of high-order displacement-tenser components results in significantly lower figures of merit in the whole explored temperature range. C1 Univ Milan, Dipartimento Sci Terra, I-20133 Milan, Italy. Tech Univ Denmark, Dept Chem, DK-2800 Lyngby, Denmark. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Artioli, G (reprint author), Univ Milan, Dipartimento Sci Terra, Via Botticelli 23, I-20133 Milan, Italy. RI Artioli, Gilberto/F-2149-2015; OI Artioli, Gilberto/0000-0002-8693-7392; Stahl, Kenny/0000-0002-4459-3026; pavese, alessandro/0000-0003-4982-2382 NR 34 TC 11 Z9 11 U1 0 U2 5 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD AUG PY 1997 VL 35 BP 1009 EP 1019 PN 4 PG 11 WC Mineralogy SC Mineralogy GA YL315 UT WOS:000070942300014 ER PT J AU Gadbois, DM Lehnert, BE AF Gadbois, DM Lehnert, BE TI Cell cycle response to DNA damage differs in bronchial epithelial cells and lung fibroblasts SO CANCER RESEARCH LA English DT Article ID SINGLE-STRAND BREAKS; HAMSTER OVARY CELLS; HYDROGEN-PEROXIDE; CIGARETTE-SMOKE; IONIZING-RADIATION; DEPENDENT KINASES; GROWTH ARREST; P53; PROTEIN; GLUTATHIONE AB Epithelial cells along the conducting airways can be more or less continuously exposed to DNA-damaging agents, which should limit their proliferation by inducing cell cycle checkpoints. Yet, paradoxically, airway epithelial cells frequently show a hyperplastic response when exposed to such agents, In this in vitro study, we assessed the hypothesis that normal human bronchial epithelial cells (BECs) are more resistant to the cell cycle-arresting effects of DNA damage than are human lung fibroblasts (HLFs), a cell type often investigated in the context of cell cycle checkpoints. Using ionizing radiation as a DNA-damaging insult, we have found that BECs indeed show less pronounced G(1) and G(2) delays than do fibroblasts, Unlike the HLFs, which ultimately enter a condition of apparently terminal arrest in the G(1) phase of the cell cycle, BECs continue proliferating following their initial, transient G(1) and G(2) delays, Radiation-induced p53 and p21(Cip1) increases were greater in HLFs than in BECs, whereas preexposure, basal levels of p53 were higher in BECs than in HLFs. The results of this investigation indicate that BECs may be less susceptible to the cell cycle-arresting effects of DNA-damaging agents, perhaps because of their higher basal levels of p53. Extension of these findings to the in vivo condition provides a possible explanation for airway epithelial cell hyperplastic responses that occur in a background of DNA-damaging stresses. Moreover, the attenuated DNA damage-induced, cell cycle checkpoint responses in BECs potentially may favor the transmission of DNA lesions to cell progeny. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,CELL & MOL BIOL GRP,LOS ALAMOS,NM 87545. FU NCRR NIH HHS [P41-RR01315] NR 69 TC 24 Z9 25 U1 1 U2 1 PU AMER ASSOC CANCER RESEARCH PI PHILADELPHIA PA PUBLIC LEDGER BLDG, SUITE 816, 150 S. INDEPENDENCE MALL W., PHILADELPHIA, PA 19106 SN 0008-5472 J9 CANCER RES JI Cancer Res. PD AUG 1 PY 1997 VL 57 IS 15 BP 3174 EP 3179 PG 6 WC Oncology SC Oncology GA XM812 UT WOS:A1997XM81200021 PM 9242446 ER PT J AU Litinski, V Chenna, A Sagi, J Singer, B AF Litinski, V Chenna, A Sagi, J Singer, B TI Sequence context is an important determinant in the mutagenic potential of 1,N-6-ethenodeoxyadenosine (epsilon A): formation of epsilon A basepairs and elongation in defined templates SO CARCINOGENESIS LA English DT Article ID CHLORIDE METABOLITE CHLOROACETALDEHYDE; POLYMERASE INSERTION FIDELITY; ETHYL CARBAMATE URETHANE; HUMAN DNA GLYCOSYLASE; ESCHERICHIA-COLI; VINYL-CHLORIDE; REVERSE-TRANSCRIPTASE; BASE-PAIRS; SITE; KINETICS AB Many laboratories have obtained data on mutagenicity of modified bases in naturally occurring DNA sequences. It has often been noted that mutation is favored in certain sequence contests, sometimes termed 'hot spots'. This approach to the contribution of neighboring sequences does not permit a systematic study of both the qualitative and quantitative mutational frequencies. In the present experiments we have chosen to use the exocyclic adduct, 1,N-6-etheno A (epsilon A), site-specifically placed in a defined 25-mer oligonucleotides in which epsilon A is flanked by differing 5' and 3' tandem bases. Mutation was assessed using an fit vitro replication assay and five polymerases of varying fidelity. The relevant central sequences were 3' --> 5' -CC-epsilon A-CC-, -GG-epsilon A-GG-, -TT-epsilon A-TT-, -AA-epsilon A-AA-, -GG-epsilon A-TT-, -TT-epsilon A-AA-, -AT-epsilon A-TT- and -TA-epsilon A-TA-. Using the Klenow fragment (Kf) (exo(+) or exo(-)) of E.coli Pol I, it was found the epsilon A is an ambiguous base and, with varying efficiencies, all four dNTPs could be inserted opposite epsilon A in all sequences. However, only 3'-->5' -TT-epsilon A-TT-, -GG-epsilon A-TT- and -AT-epsilon A-TT- were fully extended to a significant extent. The only sequences essentially blocked at the position of epsilon A were -AA-epsilon A-AA- and -TT-epsilon A-AA-. The others were intermediate. When replication was performed with Sequenase, MMLV RT or HIV RT, different patterns were observed, in which replication terminated one base prior to epsilon A, at epsilon A, Or one base after epsilon A without further extension. In favored sequences, using the Klenow fragment, an epsilon A.N pair could be extended to form normal basepairs. No extension could be demonstrated in sequences in which tandem adenines were 5' to epsilon A. Kinetic data showed that two of the epsilon A.N pairs, epsilon A.A and epsilon A.C, could form at 10 mu M or less dNTP. Which bases were preferentially inserted opposite epsilon A was a function of the flanking bases. Under the kinetic conditions used, epsilon A.T did not farm even at 1 mM dTTP. These results indicate that the chemical structure of an adduct is not the only determinant of mutagenic efficiency. It is likely that the effect of the adduct on replication is due to the changes in the structural environment conferred by the flanking bases. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DONNER LAB,BERKELEY,CA 94720. CENT RES INST CHEM,H-1525 BUDAPEST,HUNGARY. FU NCI NIH HHS [CA 47723]; NIEHS NIH HHS [ES 07368] NR 47 TC 25 Z9 25 U1 0 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD, ENGLAND OX2 6DP SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD AUG PY 1997 VL 18 IS 8 BP 1609 EP 1615 DI 10.1093/carcin/18.8.1609 PG 7 WC Oncology SC Oncology GA XQ878 UT WOS:A1997XQ87800025 PM 9276637 ER PT J AU Hyman, M Bagaasen, L AF Hyman, M Bagaasen, L TI Select a site cleanup technology SO CHEMICAL ENGINEERING PROGRESS LA English DT Article C1 PACIFIC NW LAB, ENGN TECHNOL CTR, RICHLAND, WA 99352 USA. RP Hyman, M (reprint author), BECHTEL, RICHLAND, WA USA. NR 31 TC 4 Z9 4 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0360-7275 J9 CHEM ENG PROG JI Chem. Eng. Prog. PD AUG PY 1997 VL 93 IS 8 BP 22 EP 43 PG 22 WC Engineering, Chemical SC Engineering GA XU156 UT WOS:A1997XU15600017 ER PT J AU Raduge, C Pflumio, V Shen, YR AF Raduge, C Pflumio, V Shen, YR TI Surface vibrational spectroscopy of sulfuric acid-water mixtures at the liquid-vapor interface SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SPECTRA AB Infrared-visible sum-frequency generation has been used to obtain vibrational spectra of sulfuric acid-water mixtures at the liquid-vapor interface in the OH stretch region. The spectral peaks gradually disappear with increase of sulfuric acid concentration. the dangling OH mode first, followed by the bonded OM modes. Thp results can be understood if the Liquid surfaces are assumed to possess a more or less ordered hydrogen-bonding network, (C) 1997 Published by Elsevier Science B.V. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,DEPT PHYS,BERKELEY,CA 94720. NR 26 TC 97 Z9 97 U1 0 U2 8 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 AUG 1 PY 1997 VL 274 IS 1-3 BP 140 EP 144 DI 10.1016/S0009-2614(97)00631-3 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ566 UT WOS:A1997XQ56600024 ER PT J AU Diener, MD Smith, CA Veirs, DK AF Diener, MD Smith, CA Veirs, DK TI Anaerobic preparation and solvent-free separation of uranium endohedral metallofullerenes SO CHEMISTRY OF MATERIALS LA English DT Article ID VAPOR-PRESSURE; FULLERENES; SUBLIMATION; BUCKMINSTERFULLERENE; C60 AB Safe production, handling, and separation of depleted uranium endohedral metallofullernes in an oxygen-free environment is demonstrated. Films of C-60, C-70, and M@C-60 are produced by subliming fullerenes from are-produced soot onto a mass spectrometry target (with ca. 1% impurities of higher fullerenes). Also, films consisting of higher fullerenes (empty and full) and mostly devoid of C-60 or C-70 are made by subliming at higher temperatures. The temperature of the soot must be uniform and held constant during sublimation in order to produce high-quality films. M@C-60 requires a slightly higher temperature for sublimation than empty C-60, the likely result of stronger interactions between M@C-60 and its surroundings in the soot. C1 LOS ALAMOS NATL LAB, DIV NUCL MAT TECHNOL, LOS ALAMOS, NM 87545 USA. RICE UNIV, DEPT CHEM, HOUSTON, TX 77005 USA. NR 27 TC 26 Z9 26 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD AUG PY 1997 VL 9 IS 8 BP 1773 EP 1777 DI 10.1021/cm960540o PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XR448 UT WOS:A1997XR44800012 ER PT J AU Harrison, WTA Phillips, MLF AF Harrison, WTA Phillips, MLF TI Hydrothermal syntheses and single-crystal structures of some novel guanidinium-zinc-phosphates SO CHEMISTRY OF MATERIALS LA English DT Article ID MOLECULAR-SIEVE; ZEOLITE AB The mild-condition hydrothermal syntheses and single-crystal structures of three new guanidinium zinc phosphates are reported. CN3H6 . Zn-2(HPO4)(2)H2PO4 and (CN3H6)(2) . Zn(HPO4)(2) are built up from three-dimensional Zn/P/O frameworks encapsulating guanidinium cations in 12-ring channel systems. The latter material has the lowest nodal-framework-atom density per unit volume of any open-framework phase characterized so far. (CN3H6)(6) . Zn-2(OH)(PO4)(3) . H2O is a one-dimensional phase with respect to Zn/P/O connectivity and has a unique triply bridged tetrahedral chain connectivity for simple phosphates. Crystal data: CN3H6 . Zn-2(HPO4)(2)H2PO4, M-r = 478.78, monoclinic, space group P2(1) (No. 4), a = 5.1318(4) Angstrom b = 7.8411(7) Angstrom, c = 16.510(1) Angstrom, beta = 90.110(7)degrees, V = 664.36(8) Angstrom(3), Z = 2, R = 2.43%, R-w = 2.67% [2608 observed reflections with I > 3 sigma(I)]. (CN3H6)(2) . Zn(HPO4)(2), M-r = 377.50, orthorhombic, space group Pna2(1) (No. 33), a = 10.447(2) Angstrom, b = 12.349(2) Angstrom, c = 10.225(2) Angstrom, V = 1319.2(5) Angstrom(3), Z = 4, R = 3.26%, R-w = 3.32% [2252 observed reflections with I > 3 sigma(I)]. (CN3H6)(6) . Zn-2(OH)(PO4)(3) . H2O, M-r = 811.17, trigonal, space group R (3) over bar (No. 148), a = 20.016(7) Angstrom, c = 13.955(6) Angstrom, V = 4842(4) Angstrom(3), Z = 6, R = 5.31%, R-w = 5.52% [630 observed reflections with I > 3 sigma(I)]. C1 UNIV WESTERN AUSTRALIA,DEPT CHEM,NEDLANDS,WA 6907,AUSTRALIA. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 40 TC 105 Z9 108 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD AUG PY 1997 VL 9 IS 8 BP 1837 EP 1846 DI 10.1021/cm9701264 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XR448 UT WOS:A1997XR44800020 ER PT J AU Lyon, BF Ambrose, R Rice, G Maxwell, CJ AF Lyon, BF Ambrose, R Rice, G Maxwell, CJ TI Calculation of soil-water and benthic sediment partition coefficients for mercury SO CHEMOSPHERE LA English DT Article ID METHYLMERCURY; SPECIATION AB To accurately model mercury transport to water bodies, an assessment of this pollutant's behavior in the watershed is critical. Partition coefficients, defined as an estimate of the ratio of the pollutant concentration sorbed onto soil/sediment particles to the pollutant concentration dissolved in pore water at equilibrium, is an important term in multimedia models. In this paper, partition coefficients are calculated for two broad species of mercury: inorganic mercuric mercury (Hg-II) and methylmercury (MHg). Although there is considerable variability in the calculated values, the approximate mean values for the soil-water partition coefficients range from 3.3x10(3) to 6.0x10(4) L/kg for Hg-II and 2.0x10(1) to 6.7x10(3) L/kg for MHg. For the benthic sediment partition coefficients, the values range from 5.7x10(3) to 9.9x10(5) L/kg for Hg-II, and 6.5x10(2) to 1.1x10(5) L/kg for MHg. (C) 1997 Elsevier Science Ltd. C1 US EPA, NATL EXPOSURE RES LAB, ATHENS, GA 30613 USA. US EPA, NATL CTR ENVIRONM ASSESSMENT, CINCINNATI, OH 45268 USA. OAK RIDGE NATL LAB, HLTH SCI RES DIV, OAK RIDGE, TN USA. RP Lyon, BF (reprint author), OAK RIDGE NATL LAB, MARTIN MARIETTA ENERGY SYST, 1060 COMMERCE PK, MS-6480, OAK RIDGE, TN 37831 USA. NR 30 TC 26 Z9 27 U1 2 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD AUG PY 1997 VL 35 IS 4 BP 791 EP 808 DI 10.1016/S0045-6535(97)00200-2 PG 18 WC Environmental Sciences SC Environmental Sciences & Ecology GA XM827 UT WOS:A1997XM82700007 PM 9253168 ER PT J AU Benicewicz, BC Smith, ME Earls, JD Priester, RD Douglas, EP AF Benicewicz, BC Smith, ME Earls, JD Priester, RD Douglas, EP TI Magnetic field processing of liquid-crystalline thermosets SO CHEMTECH LA English DT Article C1 LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,POLYMERS & COATINGS GRP,LOS ALAMOS,NM 87545. DOW CHEM CO USA,ORGAN PROD RES LAB,MIDLAND,MI 48674. DOW CHEM CO USA,NEW BUSINESS ORG,MIDLAND,MI 48674. UNIV FLORIDA,GAINESVILLE,FL. OI Benicewicz, Brian/0000-0003-4130-1232 NR 16 TC 6 Z9 6 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD AUG PY 1997 VL 27 IS 8 BP 44 EP 48 PG 5 WC Chemistry, Applied SC Chemistry GA XP445 UT WOS:A1997XP44500018 ER PT J AU Tsai, YS AF Tsai, YS TI Search for new mechanism of CP violation through decay of leptons and semileptonic decay of hadrons SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Symposium on Contemporary Physics CY DEC 28-30, 1996 CL NATL TAIWAN UNIV, DEPT PHYS, TAIPEI, TAIWAN HO NATL TAIWAN UNIV, DEPT PHYS ID K-MU-3 DECAYS; MODEL; NONCONSERVATION; POLARIZATION AB If CP is violated in any decay process involving leptons it will signify the existence of a new scalar boson (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. We discuss the signatures of CP violation in (1) the decay of tau and mu leptons, and (2) the semileptonic decay of pi, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. We discuss how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes. RP Tsai, YS (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD AUG PY 1997 VL 35 IS 4 BP 314 EP 329 PG 16 WC Physics, Multidisciplinary SC Physics GA XR077 UT WOS:A1997XR07700003 ER PT J AU Chen, PS AF Chen, PS TI Resonant photon-graviton conversion as a probe into inflationary universe SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Symposium on Contemporary Physics CY DEC 28-30, 1996 CL NATL TAIWAN UNIV, DEPT PHYS, TAIPEI, TAIWAN HO NATL TAIWAN UNIV, DEPT PHYS ID MICROWAVE BACKGROUND-RADIATION; MAGNETIC-FIELD; FLUCTUATIONS; CONSTRAINTS; ANISOTROPY; COSMOLOGY; FLATNESS; HORIZON; RAINBOW; ORIGIN AB Inflationary cosmology predicts the generation of both density perturbation and relic gravitons. Tests of these predictions, especially the relic gravitons, will be very crucial to the verification of inflation. Efforts have been made to distinguish different inflation models using observed anisotropies of the cosmic microwave background radiation. However, the fact that both scalar and tensor modes contribute to the Sachs-Wolfe effect renders such determination difficult. We point out that, mediated by the primordial magnetic field, the relic gravitons can resonantly convert into photons at the same frequencies. A measurement of the spectrum of these long wavelength EM waves can help to determine the power law index directly, which will distinguish different inflationary models. This opens up a new window for a glance at ''gravity's rainbow''. RP Chen, PS (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 34 TC 1 Z9 1 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD AUG PY 1997 VL 35 IS 4 BP 399 EP 406 PG 8 WC Physics, Multidisciplinary SC Physics GA XR077 UT WOS:A1997XR07700010 ER PT J AU Hartle, JB Miller, WA Williams, RM AF Hartle, JB Miller, WA Williams, RM TI Signature of the simplicial supermetric SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article ID REGGE CALCULUS; MINISUPERSPACE; SUPERSPACE; GEOMETRIES; SYMMETRY AB We investigate the signature of the Lund-Regge metric on spaces of simplicial 3-geometries which are important in some formulations of quantum gravity. Tetrahedra can be joined together to make a three-dimensional piecewise linear manifold. A metric on this manifold is specified by assigning a flat metric to the interior of the tetrahedra and values to their squared edge lengths. The subset of the space of squared edge lengths obeying triangle and analogous inequalities is simplicial configuration space. We derive the Lund-Regge metric on simplicial configuration space and show how it provides the shortest distance between simplicial 3-geometries among all choices of gauge inside the simplices for defining this metric (Regge gauge freedom). We show analytically that there is always at least one physical time-like direction in simplicial configuration space and provide a lower bound on the number of spacelike directions. We show that in the neighbourhood of points in this space corresponding to flat metrics there are space-like directions corresponding to gauge freedom in assigning the edge lengths. We evaluate the signature numerically for the simplicial configuration spaces based on some simple triangulations of the 3-sphere (S-3) and 3-torus (T-3). For the surface of a 4-simplex triangulation of S-3 we find one time-like direction and all the rest space-like over all of the simplicial configuration space. For the triangulation of T-3 around Bat space we find degeneracies in the simplicial supermetric as well as a few gauge modes corresponding to a positive eigenvalue. Moreover, we have determined that some of the negative eigenvalues are physical, i.e. the corresponding eigenvectors are not generators of diffeomorphisms. We compare our results with the known properties of continuum superspace. C1 SANTA FE INST,SANTA FE,NM 87501. UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131. UNIV CAMBRIDGE GIRTON COLL,CAMBRIDGE CB3 0JG,ENGLAND. UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,CAMBRIDGE CB3 9EW,ENGLAND. RP Hartle, JB (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,T-6,MS B288,LOS ALAMOS,NM 87545, USA. NR 26 TC 10 Z9 10 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD AUG PY 1997 VL 14 IS 8 BP 2137 EP 2155 DI 10.1088/0264-9381/14/8/013 PG 19 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XT440 UT WOS:A1997XT44000012 ER PT J AU Doerr, A Wu, XZ Ocko, BM Sirota, EB Gang, O Deutsch, M AF Doerr, A Wu, XZ Ocko, BM Sirota, EB Gang, O Deutsch, M TI Surface freezing in mixtures of molten alkanes and alcohols SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article; Proceedings Paper CT 11th International Symposium on Surfactants in Solution CY JUN 09-13, 1996 CL JERUSALEM, ISRAEL DE surface freezing; alkane mixtures; alcohol mixtures ID X-RAY-SCATTERING; LIQUID NORMAL-ALKANES; PHASE-TRANSITIONS; CAPILLARY WAVES; REFLECTIVITY; ORDER AB Surface freezing is studied in molten binary mixtures of alkanes and alcohols of different lengths using X-ray surface scattering and surface tension measurements. A crystalline monolayer (for alkanes) or bilayer (for alcohols) is formed at the surface a few degrees above the bulk freezing temperatures. The behaviour is found to be dominated by the length difference of the two components, Delta n. For small an the surface properties and structure vary continuously with concentration between those of the pure components. For large Delta n, however, the variation is discontinuous, exhibiting surface segregation. Several new phenomena, not observed in the pure components, are also found: a new surface crystalline structure in alkanes, a suppression of surface freezing for some compositions in both materials, and the inducement of surface freezing in alcohols which do not show the effect when pure. A Flory-Huggins theory based on competition between entropic mixing and a repulsive interaction due to chain length mismatch accounts well for the observed phenomena in alkanes, but requires modifications when applied to alcohols, probably due to the more complex additional headgroup interactions. (C) 1997 Elsevier Science B.V. C1 BAR ILAN UNIV,DEPT PHYS,IL-52900 RAMAT GAN,ISRAEL. CHRISTIAN ALBRECHTS UNIV KIEL,INST EXPT PHYS,D-24098 KIEL,GERMANY. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. RI Sirota, Eric/A-7633-2009 NR 28 TC 16 Z9 16 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD AUG 1 PY 1997 VL 128 IS 1-3 BP 63 EP 74 DI 10.1016/S0927-7757(96)03907-6 PG 12 WC Chemistry, Physical SC Chemistry GA XR080 UT WOS:A1997XR08000008 ER PT J AU Echekki, T AF Echekki, T TI A quasi-one-dimensional premixed flame model with cross-stream diffusion SO COMBUSTION AND FLAME LA English DT Article ID SENSITIVITY ANALYSIS; COMBUSTION; LAMINAR AB A differential quasi-one-dimensional flame model which accounts for flame curvature, lateral how expansion, and cross-stream diffusion is formulated. Expressions for the flame propagation speed (or displacement speed) are obtained by integration of the governing equations. The analysis shows that three mechanisms contribute to the enhancement of the displacement speed: a chemical mechanism associated with modifications to the reaction zone structure, lateral flow expansion, and cross-stream diffusion. An approach to study the sensitivity of the flame structure and propagation to curvature and strain rate is proposed based on the model formulation. In particular, a method for computing the curvature Markstein lengths from the solution of one-dimensional flames is described. Contributions to the Markstein length based on sensitivity analysis are shown to be associated primarily with processes in the reaction zone. (C) 1997 by The Combustion Institute. RP Echekki, T (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. RI Echekki, Tarek/C-7394-2009; OI Echekki, Tarek/0000-0002-0146-7994 NR 21 TC 5 Z9 5 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD AUG PY 1997 VL 110 IS 3 BP 335 EP 350 DI 10.1016/S0010-2180(97)00079-5 PG 16 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA XF226 UT WOS:A1997XF22600004 ER PT J AU Kilman, DG Forslund, DW AF Kilman, DG Forslund, DW TI An international collaboratory based on virtual patient records SO COMMUNICATIONS OF THE ACM LA English DT Article RP Kilman, DG (reprint author), LOS ALAMOS NATL LAB,ADV COMP LAB,POB 1663,LOS ALAMOS,NM 87544, USA. OI Forslund, David/0000-0002-6534-3392 NR 10 TC 17 Z9 17 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0001-0782 J9 COMMUN ACM JI Commun. ACM PD AUG PY 1997 VL 40 IS 8 BP 110 EP 117 DI 10.1145/257874.257898 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA XN269 UT WOS:A1997XN26900029 ER PT J AU Amthor, JS AF Amthor, JS TI Calculation of daylength SO COMPUTER APPLICATIONS IN THE BIOSCIENCES LA English DT Article RP Amthor, JS (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,MAIL STOP L-396,LIVERMORE,CA 94551, USA. RI Amthor, Jeffrey/F-2696-2016 OI Amthor, Jeffrey/0000-0002-1410-6100 NR 4 TC 1 Z9 1 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD, ENGLAND OX2 6DP SN 0266-7061 J9 COMPUT APPL BIOSCI JI Comput. Appl. Biosci. PD AUG PY 1997 VL 13 IS 4 BP 479 EP 480 PG 2 WC Computer Science, Interdisciplinary Applications SC Computer Science GA XR673 UT WOS:A1997XR67300020 PM 9283766 ER PT J AU Geiger, K AF Geiger, K TI VNI 3.1 - MC-simulation program to study high-energy particle collisions in QCD by space-time evolution of parton-cascades and parton-hadron conversion SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE event generator; high-energy particle collisions; many-body kinetics; space-time dynamics; parton evolution; cluster formation; hadronic final states ID ULTRARELATIVISTIC NUCLEAR COLLISIONS; INITIAL-STATE RADIATION; SOFT GLUON INTERFERENCE; MONTE-CARLO SIMULATION; HEAVY-ION COLLISIONS; TRANSVERSE-MOMENTUM; EVENT GENERATOR; JET PRODUCTION; HARD PROCESSES; CROSS-SECTION AB VNI is a general-purpose Monte Carlo event generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. On the basis of renormalization-group improved parton description and quantum-kinetic theory, it uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme that is governed by the dynamics itself. The causal evolution from a specific initial state (determined by the colliding beam particles) is followed by the time development of the phase-space densities of partons, pre-hadronic parton clusters, and final-state hadrons, in position space, momentum space and color space. The parton evolution is described in terms of a space-time generalization of the familiar momentum-space description of multiple (semi) hard interactions in QCD, involving 2 --> 2 parton collisions, 2 --> 1 parton fusion processes, and 1 --> 2 radiation processes. The formation of color-singlet pre-hadronic clusters and their decays into hadrons, on the other hand, is treated by using a spatial criterion motivated by confinement and a non-perturbative model for hadronization. This article gives a brief review of the physics underlying VNI, which is followed by a detailed description of the program itself. The latter program description emphasizes easy-to-use pragmatism and explains how to use the program (including a simple example), annotates input and control parameters, and discusses output data provided by it. (C) 1997 Elsevier Science B.V. RP Geiger, K (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 76 TC 72 Z9 72 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 AUG PY 1997 VL 104 IS 1-3 BP 70 EP 160 DI 10.1016/S0010-4655(97)00048-9 PG 91 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XV319 UT WOS:A1997XV31900007 ER PT J AU Sun, Y Hara, K AF Sun, Y Hara, K TI Fortran code of the Projected Shell Model: feasible shell model calculations for heavy nuclei SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE Projected Shell Model; configuration mixing; rotational symmetry; deformed nuclei; spectroscopic calculations; nuclear high-spin states ID ANGULAR-MOMENTUM PROJECTION; RARE-EARTH NUCLEI; HIGH-SPIN STATES; QUANTUM NUMBER PROJECTION AB A Fortran program is presented which conforms with the framework of the Projected Shell Model. The theory is a genuine shell model configuration mixing approach but requires only a very small configuration space. This feature enables us to interpret numerical results in simple physical terms. The present code allows detailed spectroscopic calculations for low-and high-spin states in axially deformed nuclei. It is written using a very efficient algorithm published earlier and runs extremely fast not only on Mainframes but also on Workstations or even on modem PCs. (C) 1997 Elsevier Science B.V. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. TECH UNIV MUNICH,DEPT PHYS,D-85747 GARCHING,GERMANY. RP Sun, Y (reprint author), OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831, USA. RI Sun, Yang/P-2417-2015 NR 18 TC 44 Z9 46 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 AUG PY 1997 VL 104 IS 1-3 BP 245 EP 258 DI 10.1016/S0010-4655(97)00064-7 PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XV319 UT WOS:A1997XV31900011 ER PT J AU Mulvey, M Lydeard, C Pyer, DL Hicks, KM BrimBox, J Williams, JD Butler, RS AF Mulvey, M Lydeard, C Pyer, DL Hicks, KM BrimBox, J Williams, JD Butler, RS TI Conservation genetics of North American freshwater mussels Amblema and Megalonaias SO CONSERVATION BIOLOGY LA English DT Article ID UNITED-STATES; BIVALVIA; UNIONIDAE; SPECIATION; DIVERGENCE; POPULATION AB Freshwater bivalves are among the most endangered groups of organisms in North America. Efforts to protect the declining mussel fauna are confounded by ambiguities associated with recognition of distinct evolutionary entities or species. This, in part, is due to the paucity of reliable morphological characters for differentiating taxa. We have employed allozymes and DNA sequence data to search for diagnosably distinct evolutionary entities within two problematic genera of unionid mussels, Amblema and Megalonaias. Within the genus Amblema three species are recognized based on our DNA sequence data for themitochondrial 16S rRNA and allozyme data (Amblema neislerii, A. plicata, and A. elliotti). Only one taxonomically distinct entity is recognized within the genus Megalonaias-M. nervosa. Megalonaias boykiniana of the Apalachicolan Region is not diagnosable and does not warrant specific taxonomic status. Interestingly, Megalonaias from wet of the Mississippi River, including the Mississippi, exhibited an allozyme and mtDNA haplotype frequency shift suggestive of an east-west dichotomy. The results of this study eliminate one subspecies of Amblema and increase the range of A. plicata. This should not affect the conservation status of ''currently stable'' assigned to A. plicata by Williams et at. (1993). The conservation status of A. elliotti needs to be reexamined because its distribution appears to be limited to the Coosa River System in Alabama and Georgia. C1 UNIV ALABAMA,DEPT BIOL SCI,TUSCALOOSA,AL 35487. USGS,BIOL RESOURCES DIV,GAINESVILLE,FL 32606. US FISH & WILDLIFE SERV,ASHEVILLE FIELD OFF,ASHEVILLE,NC 28801. RP Mulvey, M (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. NR 58 TC 49 Z9 50 U1 0 U2 7 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD AUG PY 1997 VL 11 IS 4 BP 868 EP 878 DI 10.1046/j.1523-1739.1997.95487.x PG 11 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA XR571 UT WOS:A1997XR57100011 ER PT J AU Wagtmann, N Rojo, S Eichler, E Mohrenweiser, H Long, EO AF Wagtmann, N Rojo, S Eichler, E Mohrenweiser, H Long, EO TI A new human gene complex encoding the killer cell inhibitory receptors and related monocyte/macrophage receptors SO CURRENT BIOLOGY LA English DT Article ID MAP; DNA AB Activation of various immune cell types can be prevented by negative signaling receptors. Natural killer (NK) cells, which can lyse tumor or virus-infected cells, express inhibitory receptors that recognise distinct 'self' class I molecules of the major histocompatibility complex [1], Recognition of self class I molecules results in a negative signal to prevent NK mediated killing of healthy cells [2]. Human and mouse NK cells express both immunoglobulin-like type I inhibitory receptors - such as the human killer cell inhibitory receptor (KIR) and the mouse gp49B glycoprotein - and lectin-like type II inhibitory receptors - such as the human CD94/NKG2 heterodimer and the mouse Ly-49 receptor family [1], These receptors use tyrosine phosphorylation motifs in their cytoplasmic tails to deliver a dominant-negative signal by recruiting the tyrosine phosphatase SHP-1 [3-5], We have identified a new family of monocyte/macrophage immunoglobulinlike receptors (MIRs) related to KIR, Two cDNA clones with sequence similarity to each other and to the gp49B gene were isolated from human lymphocytes; both encode proteins containing four immunoglobulin domains and the conserved cytoplasmic inhibitory motifs, and transcription of both was detected primarily in monocytes/macrophages, rather than T, NK, or mast cells, The MIR genes are closely linked to the KIR gene family and the gene for Fc alpha R on chromosome 19, at cytogenetic band q13.4, A mouse sequence related to MIR was mapped to a region on mouse chromosome 7 syntenic with human 19q13.4. Our findings should facilitate studies of the evolution and function of the MIR and KIR families. C1 NIAID,IMMUNOGENET LAB,ROCKVILLE,MD 20852. LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94550. RI Long, Eric/G-5475-2011 OI Long, Eric/0000-0002-7793-3728 NR 24 TC 153 Z9 155 U1 1 U2 1 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 0960-9822 J9 CURR BIOL JI Curr. Biol. PD AUG 1 PY 1997 VL 7 IS 8 BP 615 EP 618 DI 10.1016/S0960-9822(06)00263-6 PG 4 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA XP666 UT WOS:A1997XP66600035 PM 9259559 ER PT J AU Fuller, ME Manning, JF AF Fuller, ME Manning, JF TI Aerobic Gram-positive and Gram-negative bacteria exhibit differential sensitivity to and transformation of 2,4,6-trinitrotoluene (TNT) SO CURRENT MICROBIOLOGY LA English DT Article ID SP B-STRAIN; PHANEROCHAETE-CHRYSOSPORIUM; MICROBIAL TRANSFORMATION; CONTAMINATED SOILS; DEFAUNATED SOIL; DEGRADATION; CATABOLISM; METABOLISM; EFFLUX; FUNGI AB A systematic evaluation of the ability of different bacterial genera to transform 2,4,6-trinitrotoluene (TNT), and grow in its presence, was conducted. Aerobic Gram-negative organisms degraded TNT and evidenced net consumption of reduced metabolites when cultured in molasses medium, Some Gram-negative isolates transformed all the initial TNT to undetectable metabolites, with no adsorption of TNT or metabolites to cells, Growth and TNT transformation capacity of Gram-positive bacteria both exhibited 50% reductions in the presence of approximately 10 mu g TNT ml(-1). Most non-sporeforming Gram-positive organisms incubated in molasses media amended with 80 mu g TNT ml(-1) became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 mu g TNT ml(-1), indicating that TNT sensitivity is linked to metabolic activity. These results indicate that the microbial ecology of soil may be severely impacted by TNT contamination. RP Fuller, ME (reprint author), ARGONNE NATL LAB, DIV ENVIRONM RES, ER-203-J070, 9700 S CASS AVE, ARGONNE, IL 60439 USA. NR 40 TC 42 Z9 44 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0343-8651 J9 CURR MICROBIOL JI Curr. Microbiol. PD AUG PY 1997 VL 35 IS 2 BP 77 EP 83 DI 10.1007/s002849900216 PG 7 WC Microbiology SC Microbiology GA XK989 UT WOS:A1997XK98900002 PM 9216880 ER PT J AU Joy, DC AF Joy, DC TI Scanning electron microscopy for materials characterization SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID BACKSCATTERING; RECONSTRUCTION; PATTERNS; SURFACE AB Current materials are usually complex in chemistry, three-dimensional in form, and of rapidly diminishing microstructural scale. To characterize such materials the scanning electron microscope (SEM) now uses a wide range of operating conditions to target the desired sample volume, sophisticated modeling techniques to interpret the data. It also uses novel imaging modes to derive new types of information. These include depth-resolved three-dimensional data, and spatially resolved crystallographic data. C1 OAK RIDGE NATL LAB,HIGH TEMP MAT LAB,OAK RIDGE,TN 37931. RP Joy, DC (reprint author), UNIV TENNESSEE,DEPT BIOCHEM CELLULAR & MOL BIOL,ELECTRON MICROSCOPY FACIL,KNOXVILLE,TN 37996, USA. NR 47 TC 8 Z9 8 U1 2 U2 17 PU CURRENT SCIENCE LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 1359-0286 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD AUG PY 1997 VL 2 IS 4 BP 465 EP 468 DI 10.1016/S1359-0286(97)80091-5 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA XV117 UT WOS:A1997XV11700014 ER PT J AU Price, DL AF Price, DL TI Inelastic and quasielastic neutron scattering SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID VITREOUS SILICA; GLASSES; DISORDER; MODES; ORDER; SIO2 AB Inelastic neutron scattering is a technique for measuring the dynamics of condensed matter on a microscopic scale. Several dynamical regimes can be probed, including atomic momentum distributions, vibrations, and relaxation phenomena. Recent work has been carried out to investigate the dynamics of disordered materials. RP Price, DL (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013 NR 24 TC 4 Z9 4 U1 0 U2 4 PU CURRENT SCIENCE LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 1359-0286 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD AUG PY 1997 VL 2 IS 4 BP 477 EP 482 DI 10.1016/S1359-0286(97)80093-9 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA XV117 UT WOS:A1997XV11700016 ER PT J AU Paluszkiewicz, T Romea, RD AF Paluszkiewicz, T Romea, RD TI A one-dimensional model for the parameterization of deep convection in the ocean SO DYNAMICS OF ATMOSPHERES AND OCEANS LA English DT Article ID LABRADOR SEA-WATER; GREENLAND SEA; SCALE PROCESSES; CIRCULATION; ROTATION; PLUMES; ICE; VARIABILITY; ADJUSTMENT; MESOSCALE AB A one-dimensional penetrative plume model has been constructed to parameterize the process of deep convection in ocean general circulation models (OGCMs). This research is motivated by the need for OGCMs to better model the production of deep and intermediate water masses, The parameterization scheme takes the temperature and salinity profiles of OGCM grid boxes and simulates the subgrid-scale effects of convection using a one-dimensional parcel model. The model moves water parcels from the surface layer down to their level of neutral buoyancy, simulating the effect of convective plumes. While in transit, the plumes exchange water with the surrounding environment; however, the bulk of the plume water mass is deposited at the level of neutral buoyancy. Weak upwelling around the plumes is included to maintain an overall mass balance, The process continues until the negative buoyant energy of the one-dimensional vertical column is minimized. The parameterized plume entrainment rate, which plays a central role in the parameterization, is calculated using modified equations based on the physics of entraining buoyant plumes. This scheme differs from the convective adjustment techniques currently used in OGCMs, because the parcels penetrate downward with the appropriate degree of mixing until they reach their level of neutral stability. (C) 1997 Published by Elsevier Science B.V. C1 STI OPTRON, BELLEVUE, WA 98004 USA. RP PACIFIC NW NATL LAB, 1529 W SEQUIM BAY RD, SEQUIM, WA 98382 USA. NR 70 TC 32 Z9 32 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0265 EI 1872-6879 J9 DYNAM ATMOS OCEANS JI Dyn. Atmos. Oceans PD AUG PY 1997 VL 26 IS 2 BP 95 EP 130 DI 10.1016/S0377-0265(96)00482-4 PG 36 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography GA XK920 UT WOS:A1997XK92000002 ER PT J AU Small, EE Anderson, RS Repka, JL Finkel, R AF Small, EE Anderson, RS Repka, JL Finkel, R TI Erosion rates of alpine bedrock summit surfaces deduced from in situ Be-10 and Al-26 SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE erosion rates; frost action; cosmogenic radionuclides; weathering; alpine environment ID COSMOGENIC NUCLIDES; FIELD-MEASUREMENTS; EXPOSURE; ROCK; DENUDATION; INSITU; UPLIFT; EVOLUTION; SEDIMENT; HISTORY AB We have measured the concentration of in situ produced cosmogenic Be-10 and Al-26 from bare bedrock surfaces on summit flats in four western U.S. mountain ranges. The maximum mean bare-bedrock erosion rate from these alpine environments is 7.6 +/- 3.9 m My(-1). Individual measurements vary between 2 and 19 m My(-1). These erosion rates are similar to previous cosmogenic radionuclide (CRN) erosion rates measured in other environments, except for those from extremely arid regions. This indicates that bare bedrock is not weathered into transportable material more rapidly in alpine environments than in other environments, even though frost weathering should be intense in these areas. Our CRN-deduced point measurements of bedrock erosion are slower than typical basin-averaged denudation rates (similar to 50 m My(-1)). If our measured CRN erosion rates are accurate indicators of the rate at which summit flats are lowered by erosion, then relief in the mountain ranges examined here is probably increasing. We develop a model of outcrop erosion to investigate the magnitude of errors associated with applying the steady-state erosion model to episodically eroding outcrops. Our simulations show that interpreting measurements with the steady-state erasion model can yield erosion rates which are either greater or less than the actual long-term mean erosion rate. While errors resulting from episodic erosion are potentially greater than both measurement and production rate errors for single samples, the mean value of many steady-state erosion rate measurements provides a much better estimate of the long-term erosion rate. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF SANTA CRUZ,INST TECTON,SANTA CRUZ,CA 95064. LAWRENCE LIVERMORE NATL LAB,CTR ACCELERATOR MASS SPECTROMETRY,LIVERMORE,CA 94551. RP Small, EE (reprint author), UNIV CALIF SANTA CRUZ,DEPT EARTH SCI,SANTA CRUZ,CA 95064, USA. RI small, eric/B-4939-2011; Small, eric/K-6007-2015 NR 40 TC 170 Z9 180 U1 6 U2 20 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD AUG PY 1997 VL 150 IS 3-4 BP 413 EP 425 DI 10.1016/S0012-821X(97)00092-7 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XZ779 UT WOS:A1997XZ77900017 ER PT J AU Dodson, A Kennedy, BM DePaolo, DJ AF Dodson, A Kennedy, BM DePaolo, DJ TI Helium and neon isotopes in the Imnaha Basalt, Columbia River Basalt Group: Evidence for a Yellowstone plume source SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Columbia River Basalt Group; He-4/He-3; Ne-22/Ne-21; Ne-22/Ne20; plumes; geochemistry; flood basalts ID NOBLE-GASES; FLOOD BASALTS; ORIGIN; GEOCHEMISTRY; SYSTEMATICS; EVOLUTION; COMPONENT; XENOLITHS; PLATEAU AB Helium, neon, and argon isotopic compositions were measured in two flows of the Columbia River flood basalt. The Imnaha Basalt has a He-3/He-4 ratio of 11.4 times atmospheric and Ne-20/Ne-22 and Ne-21/Ne-22 ratios characteristic of a plume component. The measured He-3/He-4 is a lower limit, due to possible preferential He-3 loss and/or addition of radiogenic He-4. A Wanapum Basalt flow, erupted approximately 2 Ma later in the waning stages of volcanism, has more MORB-like noble gases. The He, Nd and Sr isotopic compositions of these lavas suggest that the Columbia River basalts were derived from the Yellowstone plume head which contained both 'high-helium' plume material and entrained depleted mantle. As the eruptions progressed the plume component in the melting region was gradually diluted or replaced. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP Dodson, A (reprint author), UNIV CALIF BERKELEY,BERKELEY CTR ISOTOPE GEOCHEM,BERKELEY,CA 94720, USA. NR 49 TC 48 Z9 51 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD AUG PY 1997 VL 150 IS 3-4 BP 443 EP 451 DI 10.1016/S0012-821X(97)00090-3 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XZ779 UT WOS:A1997XZ77900019 ER PT J AU Dale, VH AF Dale, VH TI The relationship between land-use change and climate change SO ECOLOGICAL APPLICATIONS LA English DT Article DE climate change, relation to land-use changes; forests, affected by climate change; global circulation models; global models of vegetation change; greenhouse gases, sources of; human-induced climate change; land-cover changes; land-use changes, non-climate causes; land-use change and climate change; modeling carbon flux ID NITROUS-OXIDE EMISSIONS; CENTRAL RONDONIA; GLOBAL CHANGE; CARBON-CYCLE; FORESTS; VEGETATION; PATTERNS; SOILS; CLASSIFICATION; DEFORESTATION AB Land-use change is related to climate change as both a causal factor and a major way in which the effects of climate change are expressed. As a causal factor, land use influences the flux of mass and energy, and as land-cover patterns change, these fluxes are altered. Projected climate alterations will produce changes in land-cover patterns at a variety of temporal and spatial scales, although human uses of the land are expected to override many effects. A review of the literature dealing with the relationship between land-use change and climate change clearly shows that (1) in recent centuries land-use change has had much greater effects on ecological variables than has climate change; (2) the vast majority of land-use changes have little to do with climate change or even climate; and (3) humans will change land use, and especially land management, to adjust to climate change and these adaptations will have some ecological effects. Therefore, an understanding of the nonclimatic causes of land-use change (e.g., socioeconomics and politics) are necessary to manage ecological functions effectively on regional and global scales. RP Dale, VH (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Dale, Virginia/B-6023-2009 NR 96 TC 164 Z9 198 U1 19 U2 143 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD AUG PY 1997 VL 7 IS 3 BP 753 EP 769 PG 17 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA XQ081 UT WOS:A1997XQ08100004 ER PT J AU Lingenfelser, SK Dallas, CE Jagoe, CH Chesser, RK Smith, MH Lomakin, M AF Lingenfelser, SK Dallas, CE Jagoe, CH Chesser, RK Smith, MH Lomakin, M TI Variation in blood cell DNA in Carassius carassius from ponds near Chernobyl, Ukraine SO ECOTOXICOLOGY LA English DT Article DE genotoxicity; Chernobyl; fish; flow cytometry; DNA content ID FLOW CYTOMETRIC ANALYSIS; BIOLOGICAL SIGNIFICANCE; CYTOCHALASIN-B; ANEUPLOIDY; RADIATION; EXPOSURE; CANCER; POPULATIONS; ACCIDENT; POLYPLOIDY AB Blood from approximately 400 crucian carp, Carassius carassius, from 12 ponds in the Ukraine, was analysed by flow cytometry to assess the possible relationships between chronic contaminant exposure and variation in the cellular DNA content, The ponds were located 20-30 km from Chernobyl in areas that received 3.7 x 10(10)-3.7 x 10(11) Bq Cs-137 km(-2) after the 1986 nuclear accident, as well as other radioactive and chemical contaminants. The fish populations consisted of both diploid and triploid individuals and the ploidy varied between ponds. Analysis of whole blood revealed aneuploid-like patterns in the DNA histograms of some fish, as well as hyperdiploid shoulders of the G(0)/G(1) peak. The coefficient of variation (CV) of the G(0)/G(1) peak has previously been employed to assess the variability in the DNA content of cells within individuals. The CV of individual fish varied between and within locations and very large CVs were found for some individuals. In some fish, DNA histograms showed a typical diploid or triploid cell population together with a smaller haploid population. Variations in the cellular DNA content similar to those reported here have been associated with exposure to radiation and other genotoxic agents in laboratory and field studies. However, the abnormalities we observed were not correlated with known contaminant distributions. While further work is needed, particuarly in areas with substantially higher levels of radioactivity, these results suggest that the Chernobyl accident may have long-term genetic consequences for wild organisms inhabiting contaminated areas. C1 UNIV GEORGIA,DEPT PHARMACOL & TOXICOL,COLL PHARM,ATHENS,GA 30602. UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29082. INT RES & DEV AGCY,UA-252001 KIEV 1,UKRAINE. NR 50 TC 10 Z9 10 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0963-9292 J9 ECOTOXICOLOGY JI Ecotoxicology PD AUG PY 1997 VL 6 IS 4 BP 187 EP 203 DI 10.1023/A:1018622710184 PG 17 WC Ecology; Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XQ898 UT WOS:A1997XQ89800001 ER PT J AU Theodorakis, CW Blaylock, BG Shugart, LR AF Theodorakis, CW Blaylock, BG Shugart, LR TI Genetic ecotoxicology .1. DNA integrity and reproduction in mosquitofish exposed in situ to radionuclides SO ECOTOXICOLOGY LA English DT Article; Proceedings Paper CT 14th Annual Meeting of the Society-of-Environmental-Toxicology-and-Chemistry CY NOV 14-18, 1993 CL HOUSTON, TX SP Soc Environm Toxicol & Chem DE genetic ecotoxicology; DNA strand breakage; mosquitofish; radiation; reproduction ID STRAND BREAKAGE; GAMMA-RADIATION; MAMMALIAN-CELLS; MECHANISMS; REPAIR; DAMAGE AB Female mosquitofish (Gambusia affinis) were collected from two sites located on the US Department of Energy's Oak Ridge Reservation that are contaminated with Cs-137, Sr-90, other radionuclides and chemical genotoxicants. Fish from non-radionuclide contaminated environments located off the reservation were also collected. DNA, extracted from liver tissue acid blood cells, was examined by gel electrophoresis for structural damage in the form of strand breakage. In general, the level of DNA strand breaks was elevated in fish from radionuclide-contaminated sites with observed differences in the number and type of strand breaks between liver tissue and blood cells. The number of malformed embryos was higher in fish at the contaminated sites, and varied with season. Fecundity was negatively correlated with the level of double strand breaks in the DNA of fish from one contaminated site. Females with broods that included malformed embryos had more DNA strand breakage than those that did not; and furthermore, a threshold effect was observed between the occurrence of malformed embryos and the presence of double strand breaks in the DNA of the mother. These findings have implications for both ecological risk assessment and evolutionary ecology. C1 OAK RIDGE NATL LAB, DIV ENVIRONM SCI, OAK RIDGE, TN 37831 USA. OAK RIDGE ASSOCIATED UNIV, OAK RIDGE, TN 37831 USA. SENES, OAK RIDGE, TN 37831 USA. NR 47 TC 30 Z9 33 U1 0 U2 7 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0963-9292 J9 ECOTOXICOLOGY JI Ecotoxicology PD AUG PY 1997 VL 6 IS 4 BP 205 EP 218 DI 10.1023/A:1018674727022 PG 14 WC Ecology; Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XQ898 UT WOS:A1997XQ89800002 ER PT J AU Thordarson, G Galosy, S Gudmundsson, GO Newcomer, B Sridaran, R Talamantes, F AF Thordarson, G Galosy, S Gudmundsson, GO Newcomer, B Sridaran, R Talamantes, F TI Interaction of mouse placental lactogens and androgens in regulating progesterone release in cultured mouse luteal cells SO ENDOCRINOLOGY LA English DT Article ID RAT GRANULOSA-CELLS; SECRETION; STIMULATION; RECEPTORS; PREGNANCY; OVARY; SERUM; FSH AB Pituitary hormones are essential for the maintenance of the corpus luteum in the pregnant mouse during the first half of gestation. Thereafter, hormones from the placenta take over the luteotropic role of the pituitary hormones. Mouse placental lactogen-I (mPL-I) and mPL-II, two PRL-like hormones produced in the placenta, are probably necessary for the maintenance of the corpus luteum in the latter half of pregnancy. A culture system of luteal cells from pregnant mice was developed to investigate the role of hormones from the placenta that may be important for the function of the corpus luteum. Mice were killed on days 10, 14, and 18 of pregnancy, and the corpora lutea were excised from the ovaries and digested in 0.19 collagenase, 0.002% DNase for 1 h. The resulting luteal cell suspension was plated onto 96-well plates coated with fibronectin (1 x 10(5) cells/well) and cultured for 1-3 days. Medium was changed daily. The cells were treated with various concentrations and combinations of mPL-I, mPL-II, mouse PRL, androstenedione, dihydrotestosterone, 17 beta-estradiol (E-2), testosterone, hydroxyflutamide, cycloheximide, actinomycin D, and fadrozole to study the effects of these different treatments on progesterone (P4) production. The three lactogens (mPL-I, mPL-II, and mouse PRL) all stimulated the release of P4 from the luteal cells. The potency of the lactogens was similar and did not depend on the stage of pregnancy at which the luteal tissue was obtained. However, the responsiveness of the cells to all hormone-stimulated P4 release was gradually reduced the later in pregnancy the tissue was collected. Androgens also stimulated the release of P4 from the luteal cells, and when administered together, the lactogens and the androgens acted synergistically to stimulate P4 release. The androgens acted directly but not through conversion to E-2, as determined by the findings that 1) the effects of the androjiens could not be reproduced by E-2 administration, 2) nonaromatizable androgen dihydrotestosterone was as effective as aromatizable androgens, and 3) aromatase inhibitor did not prevent the action of the androgens to stimulate the P4 release. The effect of the androgens on the P4 release was rapid, occurring within 15 min of hormone administration. It was not prevented by inhibitors of protein and RNA synthesis, and the intracellular androgen receptor antagonist hydroxyflutamide did not affect the androgen action. Therefore, the androgen effects were not mediated through the intracellular androgen receptor and de novo protein synthesis was not needed for androgen-stimulated P4 release. C1 UNIV CALIF SANTA CRUZ,DEPT BIOL,SINSHEIMER LABS,SANTA CRUZ,CA 95064. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MOREHOUSE SCH MED,DEPT PHYSIOL,ATLANTA,GA 30310. NR 23 TC 27 Z9 27 U1 0 U2 0 PU ENDOCRINE SOC PI BETHESDA PA 4350 EAST WEST HIGHWAY SUITE 500, BETHESDA, MD 20814-4110 SN 0013-7227 J9 ENDOCRINOLOGY JI Endocrinology PD AUG PY 1997 VL 138 IS 8 BP 3236 EP 3241 DI 10.1210/en.138.8.3236 PG 6 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XL842 UT WOS:A1997XL84200021 PM 9231773 ER PT J AU Crockett, AB AF Crockett, AB TI Water and wastewater quality monitoring, McMurdo Station, Antarctica SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article DE Antarctica; McMurdo Station; monitoring; wastewater; water quality ID SEMIPERMEABLE-MEMBRANE DEVICES; BENTHIC MARINE POLLUTION; CONTAMINATION AB McMurdo Station is the largest research station in Antarctica and has a population that ranges from 250 to 1200 people. Wastewater from the Station is macerated, was sometimes mixed with waste brine from the desalinization plant and is discharged to McMurdo Sound. Effluent water quality has been routinely monitored since 1989, and a special ambient water quality study was conducted by Idaho National Engineering Laboratory (INEL) personnel in 1992. Results of the effluent monitoring efforts show that low concentrations of a few organic contaminants have been detected, while concentrations of metals, particularly copper, are considerably higher. Ambient water quality and sea ice monitoring detected very few contaminants, all at very low levels. Only minor and variable dissolved oxygen depression was detected near the outfall. Diatom communities near the outfall differ in relative abundance, cell counts, and chlorophyll a content compared to control sites. For the purpose of evaluating the impact of McMurdo's effluent on ambient water quality, improved effluent monitoring and sediment quality monitoring are recommended instead of frequent monitoring of ambient water quality. RP Crockett, AB (reprint author), LOCKHEED MARTIN IDAHO TECHNOL CO,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 17 TC 17 Z9 17 U1 0 U2 6 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 AUG PY 1997 VL 47 IS 1 BP 39 EP 57 DI 10.1023/A:1005786218570 PG 19 WC Environmental Sciences SC Environmental Sciences & Ecology GA XL227 UT WOS:A1997XL22700003 ER PT J AU Workman, DJ Woods, SL Gorby, YA Fredrickson, JK Truex, MJ AF Workman, DJ Woods, SL Gorby, YA Fredrickson, JK Truex, MJ TI Microbial reduction of vitamin B-12 by Shewanella alga strain BrY with subsequent transformation of carbon tetrachloride SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID TRANSITION-METAL COENZYMES; ANAEROBIC BIOTRANSFORMATION; DEHALOGENATION; TETRACHLOROMETHANE; DECHLORINATION; ENVIRONMENTS; DEGRADATION; CORRINOIDS AB The ability of a metal-reducing bacterium to microbially reduce vitamin B-12 was determined to expand our understanding of the role vitamin B-12 plays in the transformation of halogenated compounds in microbial systems. The subsequent transformation of chlorinated methanes catalyzed by this microbially-reduced vitamin B-12 was then evaluated. When incubated in the presence of Shewanella alga strain Cry and an electron donor, the microbial reduction of vitamin B-12a to B-12r was observed as a shift in the vitamin B-12 spectrum. In treatments containing vitamin B-12 and an electron donor but without Cry, the predominant species was vitamin B-12a. The introduction of BrY into the system resulted in the production of vitamin B-12r. The transformation of carbon tetrachloride (CT), chloroform (CF), and dichloromethane (DCM) was examined in batch systems containing vitamin B-12, Shewanella alga strain Cry, and an electron donor. Transformation of both CT and CF was observed, while no significant change in the DCM concentration was detected. Carbon monoxide was the major product of CT transformation. No significant transformation of CT or CF was detected when vitamin B-12 was Omitted from the system. This work demonstrates that a metal-reducing bacterium, with no apparent ability to transform CT or CF directly, mediates the reduction of vitamin B-12, which in turn catalyzes the transformation of CT. C1 OREGON STATE UNIV, DEPT CIVIL CONSTRUCT & ENVIRONM ENGN, CORVALLIS, OR 97331 USA. RP Workman, DJ (reprint author), BATTELLE PNNL, ENVIRONM MICROBIOL GRP, POB 999, RICHLAND, WA 99352 USA. NR 26 TC 28 Z9 28 U1 1 U2 16 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 AUG PY 1997 VL 31 IS 8 BP 2292 EP 2297 DI 10.1021/es960880a PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800046 ER PT J AU Walton, JC BinShafique, S Smith, RW Gutierrez, N Tarquin, A AF Walton, JC BinShafique, S Smith, RW Gutierrez, N Tarquin, A TI Role of carbonation in transient leaching of cementitious wasteforms SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB A combined experimental and modeling program approach was applied to evaluate the role of the carbon dioxide reactive component of soil gas on the long-term performance of cementitious wasteforms. Small wasteforms were cast with Portland cement and synthetic wastewater containing metals and nitrate as a tracer. A series of wasteforms was exposed to an accelerated environment for carbonation and then subjected to transient leaching tests in deionized water. A second set of control wasteforms was not carbonated but was otherwise treated identically. Results are analyzed by comparison of experimental data with theoretical models of the leaching process. The results indicate that carbonation increases the apparent diffusion coefficient for unreactive species while resulting in chemical binding of metals through solid solution in calcite. For strontium, carbonation resulted in lower net leaching while leaching of calcium and nitrate was increased by carbonation. C1 IDAHO NATL ENGN LAB,DEPT BIOTECHNOL,IDAHO FALLS,ID 83415. RP Walton, JC (reprint author), UNIV TEXAS,DEPT CIVIL ENGN,EL PASO,TX 79968, USA. NR 15 TC 39 Z9 39 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD AUG PY 1997 VL 31 IS 8 BP 2345 EP 2349 DI 10.1021/es960964j PG 5 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800055 ER PT J AU Wan, JM Tokunaga, TK AF Wan, JM Tokunaga, TK TI Film straining of colloids in unsaturated porous media: Conceptual model and experimental testing SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GAS-WATER INTERFACE; SOIL COLUMNS; TRANSPORT; FILTRATION; PARTICLES; BACTERIA; AQUIFER; FLOW AB A film-straining theory is introduced, which proposes that transport of suspended colloids can be retarded due to physical restrictions imposed by thin water films in partially saturated porous media. A quantitative, mechanistic model is provided to predict the film-straining efficiency. In this model, the concepts of ''critical matric potential'' and ''critical saturation'' are introduced, at which thick film interconnections between pendular rings are broken and film straining begins to become effective. The modeled magnitude of colloid transport through water films depends on the ratio of colloid size to film thickness and on flow velocity. Effective penetration of hydrophilic colloids through unsaturated porous media is predicted when a system is above the critical saturation value. For colloids smaller th an the thickness of adsorbed thin water films, the model predicts that colloids can still be efficiently transported, even when the system matric potential and saturation are lower than their critical values. The model was tested through experiments on transport of hydrophilic latex particles (four sizes from 0.01 to 1.0 mu m) in sand columns of three different grain sizes and at flow rates spanning 4 orders of magnitude. The conceptual basis of this model is supported by,good agreement between the wide range of experiments and model predictions using only two adjustable parameters. RP Wan, JM (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720, USA. RI Tokunaga, Tetsu/H-2790-2014; Wan, Jiamin/H-6656-2014 OI Tokunaga, Tetsu/0000-0003-0861-6128; NR 31 TC 143 Z9 148 U1 2 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD AUG PY 1997 VL 31 IS 8 BP 2413 EP 2420 DI 10.1021/es970017q PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800064 ER PT J AU Nilsson, SK Dooner, MS Weier, HUG Frenkel, B Lian, JB Stein, GS Quesenberry, PJ AF Nilsson, SK Dooner, MS Weier, HUG Frenkel, B Lian, JB Stein, GS Quesenberry, PJ TI Osteoblast progenitors engraft from whole bone marrow transplants in nonablated mice. SO EXPERIMENTAL HEMATOLOGY LA English DT Meeting Abstract C1 UNIV MASSACHUSETTS,MED CTR,CTR CANC,WORCESTER,MA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DIV LIFE SCI,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CARDEN JENNINGS PUBL CO LTD PI CHARLOTTESVILLE PA BLAKE CTR, STE 200, 1224 W MAIN ST, CHARLOTTESVILLE, VA 22903 SN 0301-472X J9 EXP HEMATOL JI Exp. Hematol. PD AUG PY 1997 VL 25 IS 8 BP 521 EP 521 PG 1 WC Hematology; Medicine, Research & Experimental SC Hematology; Research & Experimental Medicine GA XR330 UT WOS:A1997XR33000506 ER PT J AU VanGroningen, CN Paddock, RA AF VanGroningen, CN Paddock, RA TI SMART BRIDGE: Expert bridge classification system SO EXPERT SYSTEMS WITH APPLICATIONS LA English DT Article ID REPRESENTATION AB SMART BRIDGE has been designed and built to fill a gap in the analysis function of the US military. While there are some very qualified bridge Engineers associated with the military, there are nor nearly enough to analyze every bridge that might be encountered. SMART BRIDGE can assist military personnel evaluate routes available for the movement of troops and equipment by computing the carrying capacities of each bridge on the route. This too!, usable by engineers with varying levels of expertise, determines the Military-Load Classification of bridges using various methods depending on the amount of information available. The tool has captured the complete requirements for bridge classification including: What data items are required, how to determine values for these data items, how each item interacts with the others, and how to calculate classification values. (C) 1997 Elsevier Science Ltd. RP VanGroningen, CN (reprint author), ARGONNE NATL LAB,DECIS & INFORMAT SCI DIV,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0957-4174 J9 EXPERT SYST APPL JI Expert Syst. Appl. PD AUG PY 1997 VL 13 IS 2 BP 121 EP 126 DI 10.1016/S0957-4174(97)00013-4 PG 6 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA YB491 UT WOS:A1997YB49100004 ER PT J AU Choi, IG Kim, SS Ryu, JR Han, YS Bang, WG Kim, SH Yu, YG AF Choi, IG Kim, SS Ryu, JR Han, YS Bang, WG Kim, SH Yu, YG TI Random sequence analysis of genomic DNA of a hyperthermophile: Aquifex pyrophilus SO EXTREMOPHILES LA English DT Article DE Aquifex pyrophilus; hyperthermophile; genome sequence; protease; racemase; oxidase ID NUCLEOTIDE-SEQUENCE; GEN-NOV; DEHYDROGENASE; BACTERIA; PROTEASE; ENZYME AB Aquifex pyrophilus is one of the hyperthermophilic bacteria that can grow at temperatures up to 95 degrees C. To obtain information about its genomic structure, random sequencing was performed on plasmid libraries containing 0.5-2kb genomic DNA fragments of A. pyrophilus. Comparison of the obtained sequence tags with known proteins revealed that 123 tags showed strong similarity to previously identified proteins in the PIR or Genebank databases. These included three proteases, two amino acid racemases, and three enzymes utilizing oxygen as substrate. Although the GC ratio of the genome is about 30%, the codon usage of A. pyrophilus showed biased occurrence of G and C at the third position of codons, especially those for amino acids such as asparagine, aspartic acid, cysteine, glutamine, glutamic, acid, histidine, lysine, and tyrosine. A higher ratio of positively charged amino acids in A. pyrophilus proteins as compared with proteins from mesophiles suggested that Aquifex proteins might contain increased ion-pair interaction that could help to maintain heat stability. C1 KOREA INST SCI & TECHNOL,STRUCT BIOL CTR,SEOUL,SOUTH KOREA. KOREA UNIV,DEPT AGR CHEM,SEOUL 136701,SOUTH KOREA. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. RI Choi, In-Geol/F-3152-2013 NR 19 TC 13 Z9 14 U1 1 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 1431-0651 J9 EXTREMOPHILES JI Extremophiles PD AUG PY 1997 VL 1 IS 3 BP 125 EP 134 DI 10.1007/s007920050025 PG 10 WC Biochemistry & Molecular Biology; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA YD079 UT WOS:A1997YD07900003 PM 9680318 ER PT J AU Louck, JD AF Louck, JD TI Doubly stochastic matrices in quantum mechanics SO FOUNDATIONS OF PHYSICS LA English DT Article AB The general set of doubly stochastic matrices of order n corresponding to ordinary nonrelativistic quantum mechanical transition probability matrices is given. Lande's discussion of the nonquantal origin of such matrices is noted. Several concrete examples are presented for elementary and composite angular momentum systems with the focus on the unitary symmetry associated with such systems in the spirit of the recent work of Bohr and Ulfbeck. Birkhoff's theorem on doubly stochastic matrices of order n is reformulated in a geometrical language suitable for application to the subset of quantum mechanical doubly stochastic matrices. Specifically, it is shown that the set of points on the unit sphere in cartesian n!-space is surjective with the set of doubly stochastic matrices of order n. The question is raised, but no answered, as to what is the subset of points of this unit sphere that correspond to the quantum mechanical transition probability matrices, and what is the symmetry group of this subset of matrices. RP Louck, JD (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 6 TC 12 Z9 12 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0015-9018 J9 FOUND PHYS JI Found. Phys. PD AUG PY 1997 VL 27 IS 8 BP 1085 EP 1104 DI 10.1007/BF02551435 PG 20 WC Physics, Multidisciplinary SC Physics GA YA474 UT WOS:A1997YA47400001 ER PT J AU Mann, FM Cheng, ET Wasson, O Chadwick, MB Young, PG Fischer, U Oyama, Y Forrest, RA AF Mann, FM Cheng, ET Wasson, O Chadwick, MB Young, PG Fischer, U Oyama, Y Forrest, RA TI Summary report on the 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics - Del Mar '95 SO FUSION ENGINEERING AND DESIGN LA English DT Editorial Material C1 TSI RES INC,SOLANA BEACH,CA. NIST,GAITHERSBURG,MD 20899. LOS ALAMOS NATL LAB,LOS ALAMOS,NM. FZK,KARLSRUHE,GERMANY. JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. UNITED KINGDOM ATOM ENERGY AUTHOR,ABDINGTON,ENGLAND. RP Mann, FM (reprint author), WESTINGHOUSE HANFORD CO,RICHLAND,WA 99352, USA. NR 2 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 1 EP 7 DI 10.1016/S0920-3796(97)00026-4 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500001 ER PT J AU Haight, RC Bateman, FB Grimes, SM Brient, CE Massey, TN Wasson, OA Carlson, AD Zhou, H AF Haight, RC Bateman, FB Grimes, SM Brient, CE Massey, TN Wasson, OA Carlson, AD Zhou, H TI Measurement of the angular distribution of neutron-proton scattering at 10 MeV SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE ENDF/B-VI angular distribution; neutron-proton scattering; Arndt phase shifts ID NUCLEON AB The relative angular distribution of neutrons scattered from protons was measured at an incident neutron energy of 10 MeV at the Ohio University Accelerator Laboratory. An array of 11 detector telescopes at laboratory angles of 0-60 degrees was used to detect recoil protons from neutron interactions with a CH2 target. Data for seven of these telescopes were obtained with one set of electronics and are presented here. These data, from 108 to 180 degrees for the center-of-mass scattering angles, have a small slope which agrees better with angular distributions predicted by the Arndt phase shifts than with the ENDF/B-VI angular distribution. (C) 1997 Elsevier Science S.A. C1 OHIO UNIV,ATHENS,OH 45701. NIST,GAITHERSBURG,MD 20899. BEIJING NORMAL UNIV,BEIJING 100875,PEOPLES R CHINA. RP Haight, RC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 11 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 49 EP 56 DI 10.1016/S0920-3796(97)00030-6 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500006 ER PT J AU Massey, TN Covell, TW AlQuraishi, SI Jacobs, DK Brient, CE Grimes, SM Howard, WB Yanch, J Smith, DL Micklich, BJ AF Massey, TN Covell, TW AlQuraishi, SI Jacobs, DK Brient, CE Grimes, SM Howard, WB Yanch, J Smith, DL Micklich, BJ TI Neutrons produced by proton and deuteron bombardment of beryllium SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE neutrons; proton; deuteron bombardment; beryllium ID TARGETS; YIELDS; THICK AB The method for characterizing neutrons produced by bombardment of beryllium with deuterons at energies from 3.0 to 7.0 MeV is discussed. Similar work for the characterization of the neutrons produced by the bombardment with protons from 2.0 to 4.0 MeV is presented. Both NE213 and lithium glass detectors were used in the time of flight measurement of the neutron spectra. The neutron spectrum from (27)A1(d,n) was measured at 7.440 MeV deuteron energy and an angle of 120 degrees with a U-235 fission chamber. (C) 1997 Elsevier Science S.A. C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139. MIT,DEPT NUCL ENGN,CAMBRIDGE,MA 02139. ARGONNE NATL LAB,DIV ENGN PHYS,ARGONNE,IL 60439. RP Massey, TN (reprint author), OHIO UNIV,DEPT PHYS & ASTRON,ATHENS,OH 45701, USA. NR 19 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 57 EP 63 DI 10.1016/S0920-3796(97)00031-8 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500007 ER PT J AU Haight, RC Bateman, FB Sterbenz, SM Grimes, SM Wasson, OA MaierKomor, P Vonach, H AF Haight, RC Bateman, FB Sterbenz, SM Grimes, SM Wasson, OA MaierKomor, P Vonach, H TI An update on (n,charged particle) research at WNR SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE alpha-particles; LANSCE; neutron-induced reactions ID HELIUM PRODUCTION; NEUTRONS; ISOTOPES; NICKEL; COPPER; IRON AB Neutron-induced reactions producing light charged particles continue to be investigated at the spallation fast-neutron source at the Los Alamos Neutron Science Center (LANSCE). New data on the cross sections for alpha-particle production for neutrons on Ni-58 and Ni-60 are presented from threshold to 50 MeV. Recent changes in the experiment now allow protons, deuterons, tritons, He-3 and alpha-particles to be identified. (C) 1997 Elsevier Science S.A. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. OHIO UNIV,ATHENS,OH 45701. NIST,GAITHERSBURG,MD 20899. TECH UNIV MUNICH,D-8000 MUNICH,GERMANY. INST RADIUMFORSCH & KERNPHYS,A-1090 VIENNA,AUSTRIA. NR 19 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 73 EP 77 DI 10.1016/S0920-3796(97)00033-1 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500009 ER PT J AU Chadwick, MB Ignatyuk, AV Pashchenko, AB Vonach, H Young, PG AF Chadwick, MB Ignatyuk, AV Pashchenko, AB Vonach, H Young, PG TI Nuclear model calculations of activation cross sections for fusion reactor technology SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE fusion reactor technology; International Atomic Energy Agency; radionuclide production ID ISOMER AB Intense neutron fluxes within fusion reactors that are currently being designed will lead to the activation of structural components. To assess and minimize this radioactivity, nuclear cross sections are needed for neutrons with energies up to 20 MeV. We describe research performed for the International Atomic Energy Agency (IAEA) Coordinated Research Programme on activation cross sections for fusion reactor technology, which has selected certain high-priority reactions for both experimental and theoretical study. Using statistical model codes, we have investigated: (1) excitation function cross sections for radionuclide production in the reactions Mo-94(n,p)Nb-94; Ag-109(n,2n)Ag-108m, Eu-151(n,2n)(150m) Eu, Eu-153(n,2n)(152g+m2) EU, Tb-159(n,2n) Tb-158, Re-187(n,2n)Re-186m, Hf-179(n,2n)Hf-178m2, Ir-193(n,2n)Ir-192m2, and (2) the systematical dependence of isomeric ratios on isomer spin and incident-energy. Using our calculated results for the excitation functions, along with calculations by other groups, the theoretical excitation functions have been normalized to experimental values at 14.5 MeV to produce evaluated excitation functions. These evaluations can be used within radiation transport and nuclide inventory codes to design and assess the environmental impact of fusion reactors. (C) 1997 Elsevier Science S.A. C1 INST ATOM POWER ENGN,OBNINSK,KALUZHSKAYA OBL,RUSSIA. INT ATOM ENERGY AGCY,NUCL DATA SECT,VIENNA,AUSTRIA. UNIV VIENNA,INST RADIUMFORSCH & KERNPHYS,A-1090 VIENNA,AUSTRIA. RP Chadwick, MB (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 25 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 79 EP 88 DI 10.1016/S0920-3796(97)00034-3 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500010 ER PT J AU Ikeda, Y Uno, Y Maekawa, F Smith, DL Gomes, IC Ward, RC Filatenkov, AA AF Ikeda, Y Uno, Y Maekawa, F Smith, DL Gomes, IC Ward, RC Filatenkov, AA TI An investigation of the activation of water by D-T fusion neutrons and some implications for fusion reactor technology SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE International Thermonuclear Experimental Reactor; fusion reactor technology; Monte-Carlo; neutrons ID ITER AB Several fundamental aspects of the activation of water by neutrons in D-T fusion systems have been investigated in this work. The basic physical principles involved and the status of pertinent nuclear cross-section and radioactivity data were reviewed. The integral response of the dominant O-16(n,p)N-16 reaction was calculated using several evaluated differential cross-section representations and characteristic D-T fusion neutron spectra. The impact of cross-section uncertainties was also assessed in this context. Two integral experiments were carried out at a D-T neutron generator facility to investigate the production and transport of N-16 radioactivity in a D-T fusion neutron environment. Radioactivity yield data were acquired in one of these integral experiments (IE-1) and the measured results were compared with values obtained from calculations which employed both analytical and Monte-Carlo techniques. Measurements on the shielding of high-energy gamma rays from N-16 decay by stainless steel (SS-304) and copper were performed in an additional integral experiment (IE-2) and these data were interpreted by a combination of analytical calculations and Monte-Carlo simulation. Some consequences of neutron-induced N-16 radioactivity in the cooling water of a fusion reactor were examined for two contemporary conceptual designs of the International Thermonuclear Experimental Reactor (ITER). This analysis benefitted from insight acquired through the present integral studies. It was found that this radioactivity generating process would lead to significant biological doses outside the reactor containment vessel and could also deliver potentially damaging radiation doses to superconducting magnet insulators unless care is taken to provide adequate shielding when designing a fusion reactor. (C) 1997 Elsevier Science S.A. C1 ARGONNE NATL LAB,TECHNOL DEV DIV,ARGONNE,IL 60439. JAPAN ATOM ENERGY RES INST,DEPT REACTOR ENGN,FUS NEUTRON LAB,TOKAI,IBARAKI 31911,JAPAN. RENSSELAER POLYTECH INST,DEPT ENVIRONM & ENERGY ENGN,TROY,NY 12180. VG KHLOPIN RADIUM INST,ST PETERSBURG 194021,RUSSIA. NR 39 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 107 EP 150 DI 10.1016/S0920-3796(97)00037-9 PG 44 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500013 ER PT J AU McLane, V AF McLane, V TI Nuclear data services of the Nuclear Data Centers Network available at the National Nuclear Data Center SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE Nuclear Data Centers Network; Nuclear Energy Agency Data Bank; NEA Data Bank AB The Nuclear Data Centers Network provides low and medium energy nuclear reaction data to users around the world. Online retrievals are available through the U.S. National Nuclear Data Center, the Nuclear Energy Agency Data Bank, and the IAEA Nuclear Data Section from these extensive bibliographic, experimental data, and evaluated data files. In addition to nuclear reaction data, the various databases also provide nuclear structure and decay data, and other information of interest to users. The WorldWideWeb sites at the National Nuclear Data Center and the NEA Data Bank provide access to some of the Centers' files. (C) 1997 Elsevier Science S.A. RP McLane, V (reprint author), BROOKHAVEN NATL LAB,NATL NUCL DATA CTR,UPTON,NY 11973, USA. NR 12 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 217 EP 221 DI 10.1016/S0920-3796(97)00045-8 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500021 ER PT J AU Gaeta, MJ Merrill, BJ Bartels, HW Laval, CR Topilski, L AF Gaeta, MJ Merrill, BJ Bartels, HW Laval, CR Topilski, L TI Short-term hydrogen production issues for ITER SO FUSION TECHNOLOGY LA English DT Article AB The possibility of a beryllium-steam reaction during severe accidents in the International Thermonuclear Experimental Reactor (ITER) is a safety concern because the hydrogen produced from this reaction could pose a flammability or detonation hazard. The physical mechanisms governing the production of hydrogen are Examined, and the sequence of events during a postulated ex-vessel loss-of-coolant accident (LOCA) are presented. A MELCOR simulation of an ex-vessel LOCA with simultaneous failure of the plasma shutdown system indicates that an in-vessel breach of the coolant system occurs because of first-wall melt-through. For the ITER interim first-wall/shield-blanket (FW/SB) design, this accident results in similar to 67 kg of hydrogen being produced. A similar simulation for the divertor predicts only 0.3 kg of hydrogen because of additional cooling experienced by the divertor during the blowdown of coolant into the vacuum vessel. There is evidence to indicate that beryllium evaporation from the first wall at a surface temperature of 1100 degrees C is enough to cause plasma termination through beryllium evaporation. This plasma termination occurs prior to first-wall melt-through and could minimize or eliminate significant hydrogen production. Sensitivity studies were performed by varying the first-wall temperature at which plasma termination and in-vessel breach occurs for an ex-vessel LOCA scenario. This study shows that if the plasma is terminated before 150 s (i.e., a maximum first-wall temperature of 777 degrees C) after the ex-vessel LOCA, the amount of hydrogen generated is similar to 1 kg, which is well below the flammability limit of 10 kg and gives a reasonable margin for model uncertainty. Other sensitivity studies using the FW/SB model indicated a relatively weak dependence of the hydrogen produced on in-vessel and ex-vessel breach size. In addition, a 60% reduction in coolant inventory resulted in only a one-third decrease in hydrogen production from the base case. Preliminary calculations for an in-vessel LOCA indicate that 100 kg of 50-mu m dust in the vacuum vessel could generate 2 kg of hydrogen. C1 ITER SAN DIEGO JOINT WORK SITE,LA JOLLA,CA 92037. RP Gaeta, MJ (reprint author), IDAHO NATL ENGN LAB,2525 N FREMONT AVE,IDAHO FALLS,ID 83415, USA. NR 21 TC 5 Z9 5 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD AUG PY 1997 VL 32 IS 1 BP 23 EP 34 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XP336 UT WOS:A1997XP33600003 ER PT J AU Horne, SF Greenwald, M Fredian, TW Hutchinson, IH Labombard, BL Stillerman, J Takase, Y Wolfe, SM Casper, TA Butner, DN Meyer, WH Moller, JM AF Horne, SF Greenwald, M Fredian, TW Hutchinson, IH Labombard, BL Stillerman, J Takase, Y Wolfe, SM Casper, TA Butner, DN Meyer, WH Moller, JM TI Remote: Control of alcator C-MOD from Lawrence Livermore National Laboratory SO FUSION TECHNOLOGY LA English DT Article AB Operation of a tokamak from a remote site has been demonstrated for the first time. The Alcator C-Mod tokamak, located at the Massachusetts Institute of Technology, was operated over the Internet from a remote control room set up at Lawrence Livermore National Laboratory in Calfornia. Prescription of the physics parameters such as plasma current, density, shape, heating power, and active diagnostics was accomplished entirely from the remote site using the same interface as when operating from the C-Mod control room. Engineering control of subsystems (e.g., vacuum, cooling, and power supply limits) remained under local control, providing appropriate equipment and personnel security. Although the principal purpose for running this experiment from a distance was to demonstrate the remote operation, it was planned as a productive physics run. The operation was highly successful; important new physics data were obtained, and valuable insight was gained into the potential of remote operation as well as its limitations. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Horne, SF (reprint author), MIT,CTR PLASMA FUS,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. RI Hutchinson, Ian/D-1136-2009; OI Hutchinson, Ian/0000-0003-4276-6576; Greenwald, Martin/0000-0002-4438-729X NR 14 TC 9 Z9 9 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD AUG PY 1997 VL 32 IS 1 BP 152 EP 160 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XP336 UT WOS:A1997XP33600012 ER PT J AU Ho, PC Palmer, DA AF Ho, PC Palmer, DA TI Ion association of dilute aqueous potassium chloride and potassium hydroxide solutions to 600 degrees C and 300 MPa determined by electrical conductance measurements SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CONDUCTIVITY; PRESSURES; 400-DEGREES-C; NACL-KCL-H2O; TEMPERATURES; EQUILIBRIA; CONSTANTS; EQUATION; SYSTEM; WATER AB The limiting molar conductances (Lambda(0)) and ion association constants of dilute (<0.01 mol.kg(-1)) aqueous potassium chloride and hydroxide solutions were determined by electrical conductance measurements from 200 to 600 degrees C and from 100 to 600 degrees C, respectively, and pressures up to 300 MPa. The limiting molar conductances of KOH(aq) increase with increasing temperature up to 300 degrees C and decreasing density. Above 400 degrees C and densities between 0.8 and 0.4 g.cm(-3) for KCl(aq) and between 0.8 and 0.6 g.cm(-3) for KOH(aq), Lambda(0) is nearly temperature-independent but increases linearly with decreasing density. The molal ion association constants (K-A(m)) for both KCl(aq) and KOH(aq) increase with increasing temperature and decreasing solution density. At corresponding temperatures and densities, ion association of KCl(aq) is similar in extent to NaCl(aq), whereas for KOH(aq) the values are slightly lower than for NaOH(aq). The log K-A(m) values for KCl(aq) and KOH(aq) were calculated using the Shedlovsky equation exclusively from data obtained at temperatures greater than or equal to 400 degrees C and can be represented as functions of temperature (T, Kelvin) and the logarithm of water density (rho(w), g.cm(-3)) as follows: log K-A(m)(KCl) = 0.753 - 100.21/T - (10.316 - 3598.9/T) log rho(w) and log K-A(m)(KOH) = 1.183 - 132.61/T - (13.002 - 6216.8/T) log rho(w) These expressions apply strictly at rho(w) greater than or equal to 0.4 g.cm(-3) where the measurements are most precise. Copyright (C) 1997 Elsevier Science Ltd. RP Ho, PC (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831, USA. NR 35 TC 50 Z9 53 U1 3 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 1997 VL 61 IS 15 BP 3027 EP 3040 DI 10.1016/S0016-7037(97)00146-4 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XW190 UT WOS:A1997XW19000001 ER PT J AU Peterson, ML Brown, GE Parks, GA Stein, CL AF Peterson, ML Brown, GE Parks, GA Stein, CL TI Differential redox and sorption of Cr(III/VI) on natural silicate and oxide minerals: EXAFS and XANES results SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID RAY-ABSORPTION-SPECTRA; ZERO-VALENT IRON; CHROMATE REDUCTION; SPECTROSCOPY; CHROMIUM; METALS; GROUNDWATER; ADSORPTION; INTERFACE; XAFS AB Synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy was used to investigate the reduction of aqueous Cr(VI) to Cr(III) in magnetite-bearing soils from Cr-contaminated sites. Soils from two field sites were examined, showing that mixed-valence Cr(III/VI) effluent is reduced to Cr(III) when associated with the magnetite fraction of the soil, whereas the Cr effluent associated with non-Fe(II)-bearing minerals results in mixed Cr(III/VI) adsorbates or precipitated phases. The Fe2+ in magnetite, Fe2+Fe23+O4, may act as an electron source for heterogeneous Cr(VI)-to-Cr(III) reduction, converting magnetite topotactically to maghemite, gamma-Fe23+O3. The ratio of Cr(VI)/total Cr was determined by the height of the Cr(VI) XAFS pre-edge feature, which is due to a 1s to 3d electronic transition. This pre-edge feature was calibrated as a function of Cr(VI)/Cr(III) using mixtures of Cr(III) and Cr(VI) model compounds. Environmental remediation of Cr-contaminated sites requires knowledge of chromium oxidation and speciation, and XAFS spectroscopy may be used to supply both types of information with minimal sample processing or data analysis. Copyright (C) 1997 Elsevier Science Ltd. C1 STANFORD UNIV,DEPT GEOG & ENVIRONM SCI,STANFORD,CA 94305. STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94309. UNIV WASHINGTON,SCH OCEANOG,SEATTLE,WA 98195. NR 36 TC 171 Z9 176 U1 12 U2 122 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 1997 VL 61 IS 16 BP 3399 EP 3412 DI 10.1016/S0016-7037(97)00165-8 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XY439 UT WOS:A1997XY43900010 ER PT J AU Watanabe, K Naraoka, H Wronkiewicz, DJ Condie, KC Ohmoto, H AF Watanabe, K Naraoka, H Wronkiewicz, DJ Condie, KC Ohmoto, H TI Carbon, nitrogen, and sulfur geochemistry of Archean and Proterozoic shales from the Kaapvaal Craton, South Africa SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID ORGANIC-CARBON; VENTERSDORP SUPERGROUP; TRANSVAAL SUPERGROUP; ISOTOPE VARIATIONS; VOLCANIC-ROCKS; EVOLUTION; SEDIMENTS; PYRITE; DEPOSITION; DIOXIDE AB The C, N, and S contents and delta(13)C and delta(34)S values were analyzed for 100 shale samples from ten formations, 3.0 to 2.1 Ga in age, in the central and eastern regions of the Kaapvaal Craton, South Africa. The Kaapvaal shales are characterized by generally low contents of organic C (range 0.06-2.79 wt%, average 0.47 wt%), N (range <0.01-0.09 wt%, average 0.1 wt%), and S (range <0.01-1.63 wt%, average 0.1 wt%). The low N/C (<0.005) and H/C (mostly similar to 0.2) atomic ratios in kerogens from the shales indicated that the Kaapvaal shales lost considerable amounts of N, C, S, and H during diagenesis and regional metamorphism (up to the greenschist facies). From the theoretical relationships between the H/C ratios of kerogen and organic C contents of shales, the original C contents of the Archean and Proterozoic shales from the Kaapvaal Craton are estimated to be on average similar to 2 wt%. These values are similar to the average organic C content of modern marine sediments. This suggests that the primary organic productivity and the preservation of organic matter in the ocean during the period of 3.0 to 2.1 Ga were similar to those in the Phanerozoic era, provided the flux of elastic sediments to the ocean was similar. This would also imply that the rate of O-2 accumulation in the atmosphere-ocean system, which has equaled the burial rate of organic matter in sediments, has been the same since similar to 3.0 Ga. The delta(34)S values of bulk-rock sulfides (mostly pyrite) range from +2.7 to +7.4 parts per thousand for seven sulfide-rich samples of similar to 2.9 Ga to similar to 2.6 Ga. These values are consistent with a suggestion by Ohmoto (1992) and Ohmoto et al. (1993) that most pyrite crystals in Archean shales were formed by bacterial reduction of seawater sulfate with delta(34)S values between +2 and +10 parts per thousand, and that the Archean seawater was sulfate rich. Changes in the delta(13)C(org) values during maturation of kerogen were evaluated with theoretical calculations from the experimental data of Peters et al. (1981) and Lewan (1983), and from the observations by Simoneit et al. (1981) on natural samples. These evaluations suggest that the magnitudes of delta(13)C(org) increase are much less than those estimated by Hayes et al. (1983) and Des Marais et al. (1992), and only about 2 to 3 parts per thousand for the kerogens that decreased their H/C ratios from 1.5 to less than 0.3. Based on the relationships among sulfide-S contents, organic-C contents, and delta(13)C(org) values, four different types of depositional environments are identified for the Archean and early Proterozoic shales in the Kaapvaal Craton: (I) euxinic marine basins, characterized by normal marine organisms with delta(13)C(org) = -33 +/- 3 parts per thousand; (II) near-shore, oxic marine environment, characterized by normal marine organisms with delta(13)C(org) = -31 +/- 3 parts per thousand; (III) hypersaline, low-sulfate lakes, characterized by organisms with delta(13)C(org) = -26 +/- 3 parts per thousand; and (IV) euxinic, marine basins which supported the activity of methanogenic and methanotrophic bacteria and accumulated organic matter with delta(13)C(org) = -43 +/- 3 parts per thousand. In contrast to the currently popular model positing a global anoxic ocean prior to similar to 2.2 Ga (e.g., Des Marais et al, 1992; Hayes, 1994; Logan et al., 1995), this study suggests that the development of anoxic basins, which accumulated Group II and IV sediments, occurred only regionally and episodically during the period between 3.0 Ga and 2.1 Ga. This further suggests that the normal ocean has been oxic since at least similar to 3.0 Ga Diversifications of environments, as well as of biological species, had already occurred similar to 3.0 Ga. The carbon isotope mass balance calculation suggests that the removal rates of organic C and carbonate C from the ocean and the weathering rates of organic C and carbonate C on the continents during the 3.0-2.1 Ga period were basically the same as those in the Phanerozoic era. This would have been possible only if the atmospheric P-O2 level had been basically constant since at least 3.0 Ga. The results of this study, therefore, add to a growing list of evidence that the atmosphere has been oxic (i.e., Po, >1%PAL) since at least 3.0 Ga. The list of evidence includes the sulfur isotope data on Archean sedimentary rocks (Ohmoto and Felder, 1987; Ohmoto et al., 1993), the Fe3+/Ti ratios of paleosols (Ohmoto, 1996), and the paragenesis of minerals in the ''detrital'' gold-uranium ores in pre-2.0 Ga quartz pebble beds that suggests nondetrital origins for uraninite and pyrite in these deposits (Barnicoat et al., 1997). Copyright (C) 1997 Elsevier Science Ltd. C1 ARGONNE NATL LAB, DIV CHEM TECHNOL, ARGONNE, IL 60439 USA. NEW MEXICO INST MIN & TECHNOL, DEPT EARTH & ENVIRONM SCI, SOCORRO, NM 87801 USA. PENN STATE UNIV, DEPT GEOSCI, UNIVERSITY PK, PA 16802 USA. RP TOHOKU UNIV, GRAD SCH SCI, RES CTR NAT RESOURCES & ENVIRONM GEOCHEM, SENDAI, MIYAGI 98077, JAPAN. NR 81 TC 22 Z9 22 U1 4 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 1997 VL 61 IS 16 BP 3441 EP 3459 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XY439 UT WOS:A1997XY43900013 ER PT J AU Murphy, MA Yin, A Harrison, TM Durr, SB Chen, Z Ryerson, FJ Kidd, WSF Wang, X Zhou, X AF Murphy, MA Yin, A Harrison, TM Durr, SB Chen, Z Ryerson, FJ Kidd, WSF Wang, X Zhou, X TI Did the Indo-Asian collision alone create the Tibetan plateau? SO GEOLOGY LA English DT Article ID EVOLUTION; TECTONICS; HIMALAYA AB It is widely believed that the Tibetan plateau is a late Cenozoic feature produced by the Indo-Asian collision. However, because Tibet was the locus of continental accretion and subduction throughout the Mesozoic, crustal thickening during that time may also have contributed to growth of the plateau. This portion of the geologic history was investigated in a traverse through the central Lhasa block, southern Tibet. Together with earlier studies, our mapping and geochronological results show that the Lhasa block underwent little north-south shortening during the Cenozoic. Rather, our mapping shows that similar to 60% crustal shortening, perhaps due to the collision between the Lhasa and Qiangtang blocks, occurred during the Early Cretaceous. This observation implies that a significant portion of southern Tibet was raised to perhaps 3-4 km elevation prior to the Indo-Asian collision. C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90095. UNIV WURZBURG,INST MINERAL,D-97074 WURZBURG,GERMANY. CHINESE ACAD SCI,INST GEOMECH,BEIJING,PEOPLES R CHINA. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. SUNY ALBANY,DEPT GEOL SCI,ALBANY,NY 12222. RP Murphy, MA (reprint author), UNIV CALIF LOS ANGELES,DEPT EARTH & SPACE SCI,LOS ANGELES,CA 90095, USA. RI Harrison, Timothy/E-7443-2012; Yin, An/B-3050-2014; UCLA, SIMS/A-1459-2011 NR 20 TC 333 Z9 391 U1 4 U2 34 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD AUG PY 1997 VL 25 IS 8 BP 719 EP 722 DI 10.1130/0091-7613(1997)025<0719:DTIACA>2.3.CO;2 PG 4 WC Geology SC Geology GA XR322 UT WOS:A1997XR32200012 ER PT J AU Battistelli, A Calore, C Pruess, K AF Battistelli, A Calore, C Pruess, K TI The simulator TOUGH2/EWASG for modelling geothermal reservoirs with brines and non-condensible gas SO GEOTHERMICS LA English DT Article DE TOUGH2; numerical simulator; multicomponent fluid; reservoir simulation; modelling ID SYSTEM NACL-H2O; VAPOR AB An equation-of-state (EOS) module has been developed for the TOUGH2 simulator, belonging to the MULKOM family of computer codes developed at Lawrence Berkeley National Laboratory. This module, named EWASG (Equation-of-State for Water, Salt and Gas), is able to handle three-component mixtures of water, sodium chloride, and a slightly soluble noncondensible gas (NCG). At present the NCG can be chosen to be air, CO2, CH4, H-2, or N-2. EWASG can describe liquid and gas phases, and includes precipitation and dissolution of solid salt. The dependence of density, viscosity, enthalpy, and vapour pressure of brine on salt concentration is taken into account, as well as the effects of salinity on gas solubility in the liquid phase and related heat of solution. The reduction of rock porosity because of salt precipitation is also considered, as well as the related decrease of formation permeability. Vapour pressure lowering (VPL) due to suction pressure is represented by Kelvin's equation, in which the effects of salt are considered whereas those of NCG have currently been neglected. The main assumptions made in developing the EWASG module are described, together with the correlations employed to calculate the thermophysical properties of multiphase H2O-NaCl-CO2 mixtures, which can be used to simulate the thermodynamic behaviour of commonly exploited geothermal reservoirs. (C) 1997 CNR. Published by Elsevier Science Ltd. C1 CNR,INT INST GEOTHERMAL RES,I-56126 PISA,ITALY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP Battistelli, A (reprint author), AQUATER SPA,53 VIA MIRALBELLO,I-61047 S LORENZO CAMPO,PS,ITALY. NR 50 TC 88 Z9 91 U1 2 U2 14 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0375-6505 J9 GEOTHERMICS JI Geothermics PD AUG PY 1997 VL 26 IS 4 BP 437 EP 464 DI 10.1016/S0375-6505(97)00007-2 PG 28 WC Energy & Fuels; Geosciences, Multidisciplinary SC Energy & Fuels; Geology GA XN399 UT WOS:A1997XN39900001 ER PT J AU Benezeth, P Palmer, DA Wesolowski, DJ AF Benezeth, P Palmer, DA Wesolowski, DJ TI The aqueous chemistry of aluminum. A new approach to high-temperature solubility measurements SO GEOTHERMICS LA English DT Article DE geothermal reservoir; aluminum chemistry; permeability; aluminosilicate scale ID SODIUM-CHLORIDE SOLUTIONS; HYDROXO COMPLEXES; HYDROLYSIS; SPECIATION; EQUILIBRIA; GIBBSITE; SILICON(IV); BOEHMITE; CONSTANTS; STABILITY AB Predictions of changes in geothermal reservoir permeability and porosity during exploitation and reinjection, as well as aluminosilicate scale formation in wells and plant equipment, are currently limited by inaccuracies and discrepancies in our knowledge of the aqueous speciation of aluminum and the solubilities of aluminosilicates in high-temperature brines. To address this problem, the solubility of pure synthetic boehmite (AlOOH) has been measured in noncomplexing solutions over a wide range of pH (2-10), temperature (100-290 degrees C), and ionic strength (0.03-1 mol.kg(-1) NaCl) in a hydrogen-electrode concentration cell (HECC) that provided continuous, in situ measurement of hydrogen ion molality. This represents the first such study ever reported of a pH-dependent mineral solubility profile across the entire pH range of natural waters at temperatures above 100 degrees C. Samples of the solution were withdrawn after the pH reading stabilized for analysis of total aluminum content by ion chromatography. Acidic or basic titrants could then be metered into the cell to affect a change in the pH of the solution. The direction of approach to the equilibrium saturation state could be readily varied to ensure that the system was reversible thermodynamically. A least-squares regression of the results obtained at low ionic strength was used to determine the molal solubility products (Q(s0) to Q(s4)) Of boehmite, which allowed comparison with those obtained from two recently-reported high-temperature studies of boehmite solubility, which relied on the conventional batch technique. Comparisons are also made with the low-temperature (<90 degrees C) hydrolysis constants for aluminum obtained from solubility measurements with gibbsite as the stable phase, Based on these results, it is possible to draw some general conclusions concerning the relative importance of the aluminum species in solution and to reduce significantly the number of experiments needed to define this complex system, Finally, the application of this new technique to the study of the kinetics and thermodynamics of the dissolution and formation of more complex aluminosilicate minerals is discussed. (C) 1997 CNR. Published by Elsevier Science Ltd. RP Benezeth, P (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831, USA. RI BENEZETH, Pascale/H-7969-2014 OI BENEZETH, Pascale/0000-0002-1841-2383 NR 39 TC 29 Z9 29 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0375-6505 J9 GEOTHERMICS JI Geothermics PD AUG PY 1997 VL 26 IS 4 BP 465 EP 481 DI 10.1016/S0375-6505(97)00006-0 PG 17 WC Energy & Fuels; Geosciences, Multidisciplinary SC Energy & Fuels; Geology GA XN399 UT WOS:A1997XN39900002 ER PT J AU Farmer, GT AF Farmer, GT TI Field camp: Don't rule out alternatives SO GEOTIMES LA English DT Letter RP Farmer, GT (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 SN 0016-8556 J9 GEOTIMES JI Geotimes PD AUG PY 1997 VL 42 IS 8 BP 4 EP 4 PG 1 WC Geosciences, Multidisciplinary SC Geology GA YK098 UT WOS:A1997YK09800004 ER PT J AU Wiens, RC Burnett, DS Calaway, WF Hansen, CS Lykke, KR Pellin, MJ AF Wiens, RC Burnett, DS Calaway, WF Hansen, CS Lykke, KR Pellin, MJ TI Sputtering products of sodium sulfate: Implications for Io's surface and for sodium-bearing molecules in the Io torus SO ICARUS LA English DT Article ID MULTIPHOTON IONIZATION; SPECTROSCOPY; ENERGY; NA; DISTRIBUTIONS; BOMBARDMENT; CLUSTERS; SULFIDE; SULFUR; ORIGIN AB The composition of the sodium-bearing molecular ion cloud in the vicinity of Io may yield clues to Io's geochemistry. Likely Na-bearing source minerals are Na-sulfides and Na2SO4, with the relative composition depending on the distribution of thermal environments in the upper crust, These materials will be sputtered by co-rotating torus ions either from the surface or from atmospheric aerosols. Using laser postionization, we investigated the ion-sputtered neutral products of Na2SO4 to determine whether NaO in the Io torus might be a diagnostic indicator for sodium sulfate on Io's surface or in aerosols, With an ArF excimer laser (lambda = 6.4 eV), single-photon saturation of the ionization step was achieved for NaS, Na2O, and the combination Na2S + Na2O2 at mass 78, while other species, including NaO, were close to saturation. Photofragmentation during the ionization step was minimal by all indications. The results predict sputtering ratios NaO/NaS > 8, Na2O/NaS similar to 8, Na-2/NaS greater than or equal to 6, and Na/NaS greater than or equal to 100. Multiphoton ionization was also attempted using a frequency-doubled (3.2-eV) Ti:sapphire femtosecond laser at high intensities, but saturation was not achieved for lire major species, and there was evidence of photofragmentation. Velocity distributions of the sputter products show for the first time that significant fractions of sodium-bearing molecules can be sputtered into unbound trajectories from Io's surface, with escape fractions > 50% in the case of NaO. Combining relative sputter yields and velocity distributions gives escape ratios of NaO/NaS > 10, Na-2/NaS similar to 6, and Na2O/NaS similar to 2.8 from Na2SO4. While absolute sputtering and escape ratios need to be compared for Na-sulfides versus Na2SO4, this work shows that, in the absence of significant modification by atmospheric chemical reactions, measurement of the neutral NaO/NaS ratio in the vicinity of Io could identify the major Na-bearing minerals. (C) 1997 Academic Press. C1 CALTECH, DIV GEOL & PLANETARY SCI, PASADENA, CA 91125 USA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. ARGONNE NATL LAB, DIV CHEM TECHNOL, ARGONNE, IL 60439 USA. ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 35 TC 35 Z9 35 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 1997 VL 128 IS 2 BP 386 EP 397 DI 10.1006/icar.1997.5758 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XT893 UT WOS:A1997XT89300009 ER PT J AU Zhao, JH Tone, K Weiner, SR Caleca, MA Du, HH Withrow, SP AF Zhao, JH Tone, K Weiner, SR Caleca, MA Du, HH Withrow, SP TI Evaluation of ohmic contacts to p-type 6H-SiC created by C and Al coimplantation SO IEEE ELECTRON DEVICE LETTERS LA English DT Article ID HIGH-TEMPERATURE; SILICON-CARBIDE; IMPLANTATION; DIODES AB A comparative study of specific contact resistance and sheet resistivity of p-type 6H-SiC created by Al implantation only and by C and Al coimplantation into n(-)-6H-SiC epilayer grown on n(+)-6H-SiC has been performed to address the challenging issue of ohmic contacts to the anode of SIC thyristors and other thyristor-based advanced devices. Direct experimental evidence has been obtained which shows the obvious advantage of C and Al coimplantation in terms of contact resistance and sheet resistivity, Under our experimental conditions, it is found that the specific contact resistance can be reduced by three orders of magnitude and the sheet resistivity can be improved by a factor of 6 when C and Al are coimplanted into 6H-SiC. C1 RUTGERS STATE UNIV,MICROELECT RES LAB,PISCATAWAY,NJ 08855. STEVENS INST TECHNOL,DEPT MAT SCI & ENGN,HOBOKEN,NJ 07030. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Zhao, JH (reprint author), RUTGERS STATE UNIV,DEPT ELECT & COMP ENGN,POB 909,PISCATAWAY,NJ 08855, USA. NR 13 TC 27 Z9 29 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD AUG PY 1997 VL 18 IS 8 BP 375 EP 377 DI 10.1109/55.605444 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA XM441 UT WOS:A1997XM44100003 ER PT J AU Giust, GK Sigmon, TW AF Giust, GK Sigmon, TW TI Self-aligned aluminum top-gate polysilicon thin-film transistors fabricated using laser recrystallization and gas-immersion laser doping SO IEEE ELECTRON DEVICE LETTERS LA English DT Article ID POLY-SI TFTS AB We present electrical results from polysilicon thin-film transistors (TFT's) fabricated using laser-recrystallized channels and gas-immersion laser-doped source-drain regions. A simple, four-level self-aligned aluminum top-gate process is developed to demonstrate the effectiveness of these laser processes in producing TFT's. The source-drain doping process results in source-drain sheet resistances well below 100 Omega/square. TFT held-effect mobilities in excess of 200 cm(2)/Vs are measured for the laser-fabricated unhydrogenated TFT's. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Giust, GK (reprint author), ARIZONA STATE UNIV,DEPT ELECT ENGN,TEMPE,AZ 85287, USA. NR 10 TC 20 Z9 20 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD AUG PY 1997 VL 18 IS 8 BP 394 EP 396 DI 10.1109/55.605451 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA XM441 UT WOS:A1997XM44100009 ER PT J AU McCanne, S Vetterli, M Jacobson, V AF McCanne, S Vetterli, M Jacobson, V TI Low-complexity video coding for receiver-driven layered multicast SO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS LA English DT Article DE adaptive video; hierarchical conditional replenishment; layered DCT; layered video; lightweight sessions; MBone; multicast; multicast video; multirate video; network heterogeneity; packet video; progressive video; rate-controlled video; Receiver-Driven Layered Multicast; RTP; subband coding; vic AB In recent years, the ''Internet Multicast Backbone,'' or MBone, has risen from a small, research curiosity to a large-scale and widely used communications infrastructure. A driving force behind this growth was the development of multipoint audio, video, and shared whiteboard conferencing applications. Because these real-time media are transmitted at a uniform rate to all of the receivers in the network, a source must either run at the bottleneck rate or overload portions of its multicast distribution tree. We overcome this limitation by moving the burden of rate adaptation from the source to the receivers with a scheme we call receiver-driven layered multicast, or RLM. In RLM, a source distributes a hierarchical signal by striping the different layers across multiple multicast groups, and receivers adjust their reception rate by simply joining and leaving multicast groups. In this paper, we describe a layered video compression algorithm which, when combined with RLM, provides a comprehensive solution for scalable multicast video transmission in heterogeneous networks. In addition to a layered representation, our coder has low complexity (admitting an efficient software implementation) and high loss resilience (admitting robust operation in loosely controlled environments like the Internet). Even with these constraints, our hybrid DCT/wavelet-based coder exhibits good compression performance. It outperforms all publicly available Internet video codecs while maintaining comparable run-time performance. We have implemented our coder in a ''real'' application-the UCB/LBL videoconferencing tool vie. Unlike previous work on layered video compression and transmission, we have built a fully operational system that is currently being deployed on a very large scale over the MBone. C1 SWISS FED INST TECHNOL, DEPT ELECT ENGN, CH-1015 LAUSANNE, SWITZERLAND. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT ELECT ENGN & COMP SCI, BERKELEY, CA 94720 USA. RI Vetterli, Martin/B-3612-2010 OI Vetterli, Martin/0000-0002-6122-1216 NR 55 TC 113 Z9 114 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0733-8716 EI 1558-0008 J9 IEEE J SEL AREA COMM JI IEEE J. Sel. Areas Commun. PD AUG PY 1997 VL 15 IS 6 BP 983 EP 1001 DI 10.1109/49.611154 PG 19 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA XN843 UT WOS:A1997XN84300003 ER PT J AU Hou, HQ Choquette, KD Geib, KM Hammons, BE AF Hou, HQ Choquette, KD Geib, KM Hammons, BE TI High-performance 1.06-mu m selectively oxidized vertical-cavity surface-emitting lasers with InGaAs-GaAsP strain-compensated quantum wells SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE 1.06-mu m wavelength; metalorganic vapor phase epitaxy; selective oxidation; strain-compensated quantum wells; vertical-cavity surface-emitting lasers AB We present the first room-temperature continuous-wave operation of high-performance 1.06-mu m selectively oxidized vertical-cavity surface-emitting lasers (VCSEL's). The lasers contain strain-compensated InGaAs-GaAsP quantum wells (QW's) in the active region grown by metalorganic vapor phase epitaxy, The threshold current is 190 mu A for a 2.5 x 2.5 mu m(2) device, and the threshold voltage is as low as 1.255 V for a 6 x 6 mu m(2) device. Lasing at a wavelength as long as 1.1 mu m was also achieved. We discuss the wavelength limit for lasers using the strain-compensated QW's on GaAs substrates. RP Hou, HQ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 11 TC 28 Z9 31 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD AUG PY 1997 VL 9 IS 8 BP 1057 EP 1059 DI 10.1109/68.605498 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XL185 UT WOS:A1997XL18500001 ER PT J AU Ortiz, GG Luong, SQ Sun, SZ Cheng, JL Hou, HQ Vawter, GA Hammons, BE AF Ortiz, GG Luong, SQ Sun, SZ Cheng, JL Hou, HQ Vawter, GA Hammons, BE TI Monolithic, multiple-wavelength vertical-cavity surface-emitting laser arrays by surface-controlled MOCVD growth rate enhancement and reduction SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE monolithic; multiple-wavelength lasers; patterned MOCVD growth; surface-emitting lasers; wavelength division multiplexing AB Monolithic, multiple-wavelength vertical-cavity surface-emitting laser (VCSEL) arrays have been obtained by the surface-controlled enhancement and reduction of the MOCVD epitaxial growth rate, achieving a periodic, graded wavelength span greater than 30 nm. Room-temperature (RT), electrically pumped continuous-wave (CW) lasing is demonstrated, with uniform threshold currents of 5.5 +/- 0.5 mA with typical output powers of 0.5 mW. We show here for the first time both the enhancement and the reduction of the growth rate of the entire VCSEL structure and demonstrate the controlled variation of the VCSEL lasing wavelength over a widened spectral range by exploiting both effects. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Ortiz, GG (reprint author), UNIV NEW MEXICO,CTR HIGH TECHNOL MAT,ALBUQUERQUE,NM 87131, USA. NR 7 TC 23 Z9 23 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD AUG PY 1997 VL 9 IS 8 BP 1069 EP 1071 DI 10.1109/68.605502 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XL185 UT WOS:A1997XL18500005 ER PT J AU Antoniadis, H Miller, JN Roitman, DB Cambell, IH AF Antoniadis, H Miller, JN Roitman, DB Cambell, IH TI Effects of hole carrier injection and transport in organic light-emitting diodes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID ELECTROLUMINESCENT DIODES; POLYMER AB In this paper, we examine the effects of hole carrier injection and mobility on both the electroluminescence (EL) quantum efficiency and the operating voltage of bilayer organic light-emitting diodes (OLED's). We find that hole-injection is limited by the nature of the hole injecting interface and significantly affects the operating voltage, but not the quantum efficiency of the OLED. Hole mobility is found not to affect the device quantum efficiency. We demonstrate the characteristics of an ideal ohmic contact by measuring space-charge-limited currents in a trap-free hole transporting polymer layer. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Antoniadis, H (reprint author), HEWLETT PACKARD LABS,PALO ALTO,CA 94304, USA. NR 27 TC 48 Z9 48 U1 3 U2 25 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD AUG PY 1997 VL 44 IS 8 BP 1289 EP 1294 DI 10.1109/16.605470 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XN639 UT WOS:A1997XN63900018 ER PT J AU Klein, GJ Teng, X Jagust, WJ Eberling, JL Acharya, A Reutter, BW Huesman, RH AF Klein, GJ Teng, X Jagust, WJ Eberling, JL Acharya, A Reutter, BW Huesman, RH TI A methodology for specifying PET VOI's using multimodality techniques SO IEEE TRANSACTIONS ON MEDICAL IMAGING LA English DT Article DE brain; multimodality; positron emission tomography; volume-of-interest ID IMAGE REGISTRATION; MR-IMAGES; BRAIN; LOCALIZATION; QUANTITATION; VALIDATION; TOMOGRAPHY; REGION; CT AB Volume-of-interest (VOI) extraction for radionuclide and anatomical measurements requires correct identification and delineation of the anatomical feature being studied, We have developed a toolset for specifying three-dimensional (3-D) VOI's on a multislice positron emission tomography (PET) dataset, The software is particularly suited for specifying cerebral cortex VOI's which represent a particular gyrus or deep brain structure, A registered 3-D magnetic resonance image (MRI) dataset is used to provide high-resolution anatomical information, both as oblique two-dimensional (2-D) sections and as volume renderings of a segmented cortical surface, VOI's are specified indirectly in two dimensions by drawing a stack of 2-D regions on the MRI data, The regions are tiled together to form closed triangular mesh surface models, which are subsequently transformed into the observation space of the PET scanner, Quantification by this method allows calculation of radionuclide activity in the VOI's, as well as their statistical uncertainties and correlations, The methodology for this type of analysis and validation results are presented. RP Klein, GJ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR FUNCT IMAGING,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL25840]; NIA NIH HHS [AG05890, AG12435] NR 31 TC 30 Z9 30 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0278-0062 J9 IEEE T MED IMAGING JI IEEE Trans. Med. Imaging PD AUG PY 1997 VL 16 IS 4 BP 405 EP 415 DI 10.1109/42.611350 PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Engineering, Electrical & Electronic; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Computer Science; Engineering; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA XP725 UT WOS:A1997XP72500005 PM 9262998 ER PT J AU Tantawi, SG Ruth, RD Vlieks, AE Zolotorev, M AF Tantawi, SG Ruth, RD Vlieks, AE Zolotorev, M TI Active high-power RF pulse compression using optically switched resonant delay lines SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE photoconductive devices; photonic switching systems; pulse compression methods; pulse generation AB We present the design and a proof of principle experimental results of an optically controlled high-power RF pulse-compression system, In principle, the design should handle a few hundreds of megawatts of paw-cr at S-band. The system is based on the switched resonant delay-line theory [I], It employs resonant delay lines as a means of storing RF energy. The coupling tee the lines is optimized for maximum energy; storage during the charging phase, To discharge the lines, a high-power microwave switch increases the coupling to the lines just before the start of the output pulse, The high-power microwave switch required for this system is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE01 mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability. C1 CAIRO UNIV,DEPT ELECT COMMUN ENGN,GIZA,EGYPT. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Tantawi, SG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 20 TC 28 Z9 28 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD AUG PY 1997 VL 45 IS 8 BP 1486 EP 1492 DI 10.1109/22.618460 PN 2 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA XT119 UT WOS:A1997XT11900033 ER PT J AU Moses, WW Virador, PRG Derenzo, SE Huesman, RH Budinger, TF AF Moses, WW Virador, PRG Derenzo, SE Huesman, RH Budinger, TF TI Design of a high-resolution, high-sensitivity PET camera for human brains and small animals SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1996 Medical Imaging Conference (MIC) / Nuclear Science Symposium (NSS) CY NOV 05-09, 1996 CL ANAHEIM, CA SP Inst Elect & Electr Engineers ID SCANNER; PERFORMANCE; TRANSMISSION; DETECTOR AB We present design parameters for a 3-D PET camera with high sensitivity (35 cm detector ring diameter, 15 cm axial field of view) and isotropic high resolution provided by detector modules capable of depth of interaction (DOI) measurement. Detector modules are made of LSO crystals (3 mm square by 30 mm deep) - the small module size and short decay time of LSO reduce the detector dead time by a factor of 14 compared to conventional EGO detector modules and narrow the coincidence window width to 4 ns. This yields an expected peak noise equivalent count rate of 800 kcps and noise equivalent sensitivity of 1370 kcps/mu Ci/ce with a 20 cm diameter phantom - three to five times higher than conventional scanners. With 5 mm fwhm DOI resolution, the expected reconstructed spatial resolution is <3.0 mm fwhm throughout the entire field of view. Depth of interaction measurement information is incorporated into the reconstruction algorithm by rebinning onto a regularly spaced grid. Attenuation correction is performed with an orbiting singles transmission source. RP Moses, WW (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 21 TC 55 Z9 55 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1997 VL 44 IS 4 BP 1487 EP 1491 DI 10.1109/23.632691 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA XP919 UT WOS:A1997XP91900003 ER PT J AU Klein, GJ Reutter, BW Huesman, RH AF Klein, GJ Reutter, BW Huesman, RH TI Non-rigid summing of gated PET via optical flow SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1996 Medical Imaging Conference (MIC) / Nuclear Science Symposium (NSS) CY NOV 05-09, 1996 CL ANAHEIM, CA SP Inst Elect & Electr Engineers ID VELOCITY-FIELDS; IMAGES; HEART AB A method for summing together datasets from gated cardiac PET acquisitions is described. Optical flow techniques are used to accurately model non-rigid motion present during the cardiac cycle so that a one-to-one mapping is found between each voxel of two gated volumes. Using this mapping, image summing can take place, producing a composite dataset with improved statistics and reduced motion-induced blur. Results using data from a gated cardiac study on a dog are presented. RP Klein, GJ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR FUNCT IMAGING,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 8 TC 70 Z9 70 U1 5 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1997 VL 44 IS 4 BP 1509 EP 1512 DI 10.1109/23.632704 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA XP919 UT WOS:A1997XP91900007 ER PT J AU Toney, JE Brunett, BA Schlesinger, TE James, RB AF Toney, JE Brunett, BA Schlesinger, TE James, RB TI Photocurrent mapping as a probe of transport properties and electric field distributions in cadmium zinc telluride detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1996 Medical Imaging Conference CY NOV 07-09, 1996 CL ANAHEIM, CA DE cadmium zinc telluride; material uniformity; photocurrent mapping; radiation detectors AB We have performed two-dimensional cross-sectional photocurrent mapping of Cd0.9Zn0.1Te detectors grown by the high-pressure Bridgman method as a means of probing the electric field distribution, We have analyzed the results using a model based on the drift-diffusion equation, In the case of a uniform electric field and excitation far from the electrodes, the result is virtually. identical in form to the Hecht relation, We adapt the Hecht relation to analyze photocurrent data and generalize it to the case of a nonuniform electric field, The spatial distribution of photocurrent for the material that we have examined suggests a nonuniformity. in either the electric field or the electron mobility-lifetime product, These observations may help to explain the slope changes observed in detector response pulses. C1 SANDIA NATL LABS,LIVERMORE,CA 94550. RP Toney, JE (reprint author), CARNEGIE MELLON UNIV,DEPT ELECT & COMP ENGN,PITTSBURGH,PA 15213, USA. NR 9 TC 9 Z9 10 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1997 VL 44 IS 4 BP 1684 EP 1691 DI 10.1109/23.604133 PN 2 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA XP921 UT WOS:A1997XP92100009 ER PT J AU Ziock, KP Bixler, J Cline, T Stilwell, D Sheppard, D Hurley, K Berg, P Primbsch, JH SlassiSenou, S Madden, N Anfimov, DS Chernenko, AM Isupov, OM Litvak, ML Litvin, DA Loznikov, VM Mitrofanov, IG Pozanenko, AS Tonshev, AK Ushakov, DA AF Ziock, KP Bixler, J Cline, T Stilwell, D Sheppard, D Hurley, K Berg, P Primbsch, JH SlassiSenou, S Madden, N Anfimov, DS Chernenko, AM Isupov, OM Litvak, ML Litvin, DA Loznikov, VM Mitrofanov, IG Pozanenko, AS Tonshev, AK Ushakov, DA TI The gamma-ray burst monitor for the Russian Mars 1996 mission SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1996 Medical Imaging Conference CY NOV 07-09, 1996 CL ANAHEIM, CA DE bursts; gamma-ray AB We describe an innovative detector designed primarily for the study of cosmic gamma-ray bursts aboard interplanetary. spacecraft. The experiment is a fully functional, low cost, low mass, low-power instrument, which, when combined with other similar instruments, has the capability of localizing bursts to arcminute precision, The burst monitor is based on a photomultiplier tube and a plastic/CsI(Tl) phoswich detector and records photons in the 20-150-keV energy range with time resolutions up to several milliseconds, In addition, it records photon energy spectra, Events in the plastic scintillator are distinguished by a pulse shape discrimination circuit and are used to count electrons and protons, In a planetary orbiter or fly-by mission, this capability can be used to detect the presence of a magnetosphere. We describe in detail a version of this instrument which was built for the Russian Mars 1996 mission. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. SPACE RES INST,MOSCOW,RUSSIA. RP Ziock, KP (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1997 VL 44 IS 4 BP 1692 EP 1701 DI 10.1109/23.604134 PN 2 PG 10 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA XP921 UT WOS:A1997XP92100010 ER PT J AU Anders, S Anders, A AF Anders, S Anders, A TI Special issue on vacuum discharge plasmas SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Editorial Material RP Anders, S (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 0 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 1997 VL 25 IS 4 BP 519 EP 520 DI 10.1109/TPS.1997.640658 PG 2 WC Physics, Fluids & Plasmas SC Physics GA XY530 UT WOS:A1997XY53000001 ER PT J AU Schulke, T Anders, A Siemroth, P AF Schulke, T Anders, A Siemroth, P TI Macroparticle filtering of high-current vacuum arc plasmas SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT XVIIth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) CY JUL 20-26, 1996 CL LAWRENCE BERKELEY NATL LAB, BERKELEY, CA SP Amer Phys Soc, Amer Vacuum Soc, Cooper Power Syst, IEEE, Dielect & Elect Insulat Soc, Lawrence Berkeley Natl Lab, Lawrence Livermore Natl Lab, Los Alamos Natl Lab, Sandia Natl Lab, US DOE HO LAWRENCE BERKELEY NATL LAB DE carbon films; deposition; filtering; hard coatings; high-current; microparticle; plasma; vacuum arc ID CURVED MAGNETIC FILTERS; DEPOSITION; FILMS AB The transport of vacuum are plasmas through a 90 degrees curved magnetic macroparticle filter was investigated using a high-current pulsed are source with a carbon cathode, The peak are current was in the kiloampiere range, exceeding considerably the level of what has been reported in the literature, The main question investigated was whether magnetic macroparticle filters could be scaled up while maintaining the transport efficiency of small filters, In front of the cathode, we found that are current dependent total ion saturation currents were-in the range from 10% to 23% of the are current, The best relative transmission was 25% (time integrated output/time integrated input) at a duct wall bias of 12.5 V and at an axial magnetic field of about 100 mT, The measured relative transmission of the used high-current arrangement is comparable to what has been observed with other low-current filters, Tbe absolute measurable ion saturation currents at the filter exit reached 70 A at an are current of about 1000 A. C1 FRAUNHOFER INST MAT PHYS & SURF ENGN,IWS,D-01277 DRESDEN,GERMANY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 12 TC 40 Z9 41 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 1997 VL 25 IS 4 BP 660 EP 664 DI 10.1109/27.640681 PG 5 WC Physics, Fluids & Plasmas SC Physics GA XY530 UT WOS:A1997XY53000024 ER PT J AU Anders, S Anders, A Dickinson, MR MacGill, RA Brown, IG AF Anders, S Anders, A Dickinson, MR MacGill, RA Brown, IG TI S-shaped magnetic macroparticle filter for cathodic arc deposition SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT XVIIth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) CY JUL 20-26, 1996 CL LAWRENCE BERKELEY NATL LAB, BERKELEY, CA SP Amer Phys Soc, Amer Vacuum Soc, Cooper Power Syst, IEEE, Dielect & Elect Insulat Soc, Lawrence Berkeley Natl Lab, Lawrence Livermore Natl Lab, Los Alamos Natl Lab, Sandia Natl Lab, US DOE HO LAWRENCE BERKELEY NATL LAB DE films; filtering; plasma generation; vacuum arcs ID DIAMOND-LIKE CARBON; THIN-FILMS; VACUUM; PLASMAS; TRANSPORT; SYSTEM; ENERGY AB A new magnetic macroparticle fitter design consisting of two 90 degrees filters forming an S shape is described, The transport properties of this S filter are investigated using Langmuir and deposition probes, It is shown that the filter efficiency is the product of the efficiencies of two 90 degrees filters, and the deposition rate is still acceptably high to perform thin-film deposition, Films of amorphous hard carbon have been deposited using a 90 degrees filter and the S filter, and the macroparticle contents of the firms are compared. RP Anders, S (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016 OI Anders, Andre/0000-0002-5313-6505; NR 18 TC 59 Z9 61 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 1997 VL 25 IS 4 BP 670 EP 674 DI 10.1109/27.640683 PG 5 WC Physics, Fluids & Plasmas SC Physics GA XY530 UT WOS:A1997XY53000026 ER PT J AU Anders, A Brown, IG MacGill, RA Dickinson, MR AF Anders, A Brown, IG MacGill, RA Dickinson, MR TI Vacuum-spark metal ion source based on a modified Marx generator SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT XVIIth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) CY JUL 20-26, 1996 CL LAWRENCE BERKELEY NATL LAB, BERKELEY, CA SP Amer Phys Soc, Amer Vacuum Soc, Cooper Power Syst, IEEE, Dielect & Elect Insulat Soc, Lawrence Berkeley Natl Lab, Lawrence Livermore Natl Lab, Los Alamos Natl Lab, Sandia Natl Lab, US DOE HO LAWRENCE BERKELEY NATL LAB DE ion-charge state distribution; ion sources; Marx generator; metal ion beams; plasma generation ID PLASMA; DENSITY AB The plasma-generating parts of ion sources including their power supplies are usually floated to high potential (ion extraction voltage), thus requiring great insulation efforts and causing high costs for high-energy ion beams, A new concept for pulsed ion sources is presented in which a single power supply is used to simultaneously produce the plasma and high extractor voltage via a modified Marx generator, Proof of-principle experiments have been performed with high-current spark discharges in vacuum where multiply charged ions are produced with this Marx-generator-based ion source (''Magis''), Using ''Maggs,'' it has been demonstrated that pulsed ion beams of very high energies can be obtained with relatively low voltage, For copper, ions of charge states up to 7+ have been found whose energy was 112 keV for a charging voltage of only 10 kV. RP UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 11 TC 11 Z9 11 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 EI 1939-9375 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 1997 VL 25 IS 4 BP 718 EP 721 DI 10.1109/27.640693 PG 4 WC Physics, Fluids & Plasmas SC Physics GA XY530 UT WOS:A1997XY53000036 ER PT J AU Miley, GH Gu, YB DeMora, JM Stubbers, RA Hochberg, TA Nadler, JH Anderl, RA AF Miley, GH Gu, YB DeMora, JM Stubbers, RA Hochberg, TA Nadler, JH Anderl, RA TI Discharge characteristics of the spherical inertial electrostatic, confinement (IEC) device SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT XVIIth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) CY JUL 20-26, 1996 CL LAWRENCE BERKELEY NATL LAB, BERKELEY, CA SP Amer Phys Soc, Amer Vacuum Soc, Cooper Power Syst, IEEE, Dielect & Elect Insulat Soc, Lawrence Berkeley Natl Lab, Lawrence Livermore Natl Lab, Los Alamos Natl Lab, Sandia Natl Lab, US DOE HO LAWRENCE BERKELEY NATL LAB DE hollow cathode discharge; inertial electrostatic confinement (IEC); microchannels; neutron source; plasma breakdown; spherical cathode AB The University of Illinois inertial electrostatic confinement (IEC) device provides 10(7) 2.5 MeV D-D neutrons/second when operated with a steady-state deuterium discharge at 70 kV [1], Being compact and lightweight, the IEC potentially represents an attractive portable neutron source for activation analysis applications [2], The plasma discharge in the IEC is unique, using a spherical grid in a spherical vacuum vessel with the discharge formed between the grid and the vessel wall, while the -70 kV grid (cathode) also serves to extract high-energy ions, Two key features of the IEC discharge are discussed: 1) the breakdown voltage characteristics as a function of pressure-grid/wall distance (pd), and 2) the formation of ion ''microchannels'' that carry the main ion flow through grid openings. C1 RICHLAND COMMUNITY COLL,DEPT PHYS,DECATUR,IL 62521. IDAHO NATL ENGN LAB,LITCO,IDAHO FALLS,ID 83415. RP Miley, GH (reprint author), UNIV ILLINOIS,FUS STUDIES LAB,URBANA,IL 61801, USA. NR 12 TC 39 Z9 39 U1 0 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 1997 VL 25 IS 4 BP 733 EP 739 DI 10.1109/27.640696 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XY530 UT WOS:A1997XY53000039 ER PT J AU Alt, JT Anderson, MD Jungst, RG AF Alt, JT Anderson, MD Jungst, RG TI Assessment of utility side cost savings from battery energy storage SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article; Proceedings Paper CT 1996 IEEE/PES Summer Meeting CY JUL 28-AUG 01, 1996 CL DENVER, CO SP IEEE Power Engn Soc, PES AB A method of determining the dynamic operating cost benefits of energy storage systems far utility applications is presented, The production costing program DYNASTORE is used to analyze economic benefits for ''utility B,'' an isolated island utility, using heuristic unit commitment algorithms, The unit commitment fs done using chronologic Head data and a detailed model of the utility characteristics, Several unit commitment scenarios are run for utility B, rand the results are presented. Comparisons between various Battery Energy Storage System (BESS) applications, as well as cases with and without battery storage, are shown, Results show that for utility B, a BESS of 300 MW size used for spinning reserve provides the greatest economic benefit. C1 SANDIA NATL LABS,BATTERY DEV DEPT,ALBUQUERQUE,NM 87185. RP Alt, JT (reprint author), UNIV MISSOURI,DEPT ELECT ENGN,ROLLA,MO 65401, USA. NR 18 TC 21 Z9 21 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD AUG PY 1997 VL 12 IS 3 BP 1112 EP 1118 DI 10.1109/59.630450 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA XM561 UT WOS:A1997XM56100024 ER PT J AU Pierre, JW Trudnowski, DJ Donnelly, MK AF Pierre, JW Trudnowski, DJ Donnelly, MK TI Initial results in electromechanical mode identification from ambient data SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article; Proceedings Paper CT 1996 IEEE/PES Summer Meeting CY JUL 28-AUG 01, 1996 CL DENVER, CO SP IEEE Power Engn Soc, PES DE system identification; electromechanical mode identification; Prony analysis; whitening filter AB Power system loads are constantly changing. Over a time-span of a few minutes, these changes are primarily random. The random load variations act as a constant low-level excitation to the electromechanical dynamics of the system which shows up as ambient noise in field measured voltage, current, and power signals. Assuming the random variations are white and stationary over an analysis window, it is theoretically possible to estimate the electromechanical modal frequencies and damping from the spectral content of the ambient noise. In this paper, field collected ambient noise is analyzed by solving the Wiener-Hopf linear prediction equations to estimate the modal frequency and damping. These estimates are then compared with results from a Prony analysis on a ringdown resulting from a 1400 MW brake insertion under the same operating conditions as the ambient data. Results show that estimates are consistent between the ambient and ringdown analysis indicating that it is possible to estimate a system's electromechanical characteristics simply from ambient data. These results demonstrate that it may be possible to provide power system control and operation algorithms with a real-time estimate of modal frequency and damping. C1 MONTANA TECH UNIV, BUTTE, MT 59701 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Pierre, JW (reprint author), UNIV WYOMING, LARAMIE, WY 82071 USA. NR 12 TC 141 Z9 159 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD AUG PY 1997 VL 12 IS 3 BP 1245 EP 1250 DI 10.1109/59.630467 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA XM561 UT WOS:A1997XM56100076 ER PT J AU Wilson, RE AF Wilson, RE TI Initial results in electromechanical mode identification from ambient data - Discussion SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Editorial Material RP Wilson, RE (reprint author), US DOE,WESTERN AREA POWER ADM,MONTROSE,CO 81401, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD AUG PY 1997 VL 12 IS 3 BP 1251 EP 1251 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA XM561 UT WOS:A1997XM56100077 ER PT J AU Lewis, CL Maciejewski, AA AF Lewis, CL Maciejewski, AA TI Fault tolerant operation of kinematically redundant manipulators for locked joint failures SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article DE fault tolerance; Jacobian matrices; kinematically redundant; manipulator kinematics; manipulators; redundant systems ID DESIGN AB This paper studies the degree to which the kinematic redundancy of a manipulator may be utilized for failure tolerance. A redundant manipulator is considered to be fault tolerant with respect to a given task if it is guaranteed to be capable of performing the task after any one of its joints has failed and is locked in place. A method is developed for determining the necessary constraints which insure the failure tolerance of a kinematically redundant manipulator with respect to a given critical task. This method is based on estimating the bounding boxes enclosing the self-motion manifolds for a given set of critical task points. The intersection of these bounding boxes provides a set of artificial joint limits that may guarantee the reachability of the task points after a joint failure. An algorithm for dealing with the special case of 2-D self-motion surfaces is presented. These techniques are illustrated on a PUMA 560 that is used for a 3-D Cartesian positioning task. C1 PURDUE UNIV,SCH ELECT & COMP ENGN,W LAFAYETTE,IN 47907. RP Lewis, CL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 19 TC 73 Z9 84 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD AUG PY 1997 VL 13 IS 4 BP 622 EP 629 DI 10.1109/70.611335 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA XN631 UT WOS:A1997XN63100014 ER PT J AU Kimmel, R Kiryati, N Bruckstein, AM AF Kimmel, R Kiryati, N Bruckstein, AM TI Analyzing and synthesizing images by evolving curves with the Osher-Sethian method SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE shape from shading; halftoning; offsets; distance maps; minimal geodesics; segmentation; numerical methods ID LEVEL SETS; SHORTEST PATHS; DISTANCE MAPS; SHAPE; SURFACES; PROPAGATION; CURVATURE; EVOLUTION; FRONTS AB Numerical analysis of conservation laws plays an important role in the implementation of curve evolution equations. This paper reviews the relevant concepts in numerical analysis and the relation between curve evolution, Hamilton-Jacobi partial differential equations, and differential conservation laws. This close relation enables us to introduce finite difference approximations, based on the theory of conservation laws, into curve evolution. It is shown how curve evolution serves as a powerful tool for image analysis, and how these mathematical relations enable us to construct efficient and accurate numerical schemes. Some examples demonstrate the importance of the CFL condition as a necessary condition for the stability of the numerical schemes. C1 TECHNION ISRAEL INST TECHNOL, DEPT ELECT ENGN, IL-32000 HAIFA, ISRAEL. TECHNION ISRAEL INST TECHNOL, DEPT COMP SCI, IL-32000 HAIFA, ISRAEL. RP UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, MAIL STOP 50A-2152, BERKELEY, CA 94720 USA. NR 48 TC 10 Z9 11 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-5691 EI 1573-1405 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD AUG PY 1997 VL 24 IS 1 BP 37 EP 55 DI 10.1023/A:1007970107971 PG 19 WC Computer Science, Artificial Intelligence SC Computer Science GA XV644 UT WOS:A1997XV64400003 ER PT J AU Cohen, LD Kimmel, R AF Cohen, LD Kimmel, R TI Global minimum for active contour models: A minimal path approach SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE shape modeling; deformable models snakes; path of minimal cost; level sets; segmentation; feature extraction; energy minimization; partial differential equations; curve evolution ID VISCOSITY SOLUTIONS; SHORTEST PATHS; TRACKING; ALGORITHMS; SURFACES; SHAPE AB A new boundary detection approach for shape modeling is presented. It detects the global minimum of an active contour model's energy between two end points. Initialization is made easier and the curve is not trapped at a local minimum by spurious edges. We modify the ''snake'' energy by including the internal regularization term in the external potential term. Our method is based on finding a path of minimal length in a Riemannian metric. We then make use of a new efficient numerical method to find this shortest path. It is shown that the proposed energy, though based only on a potential integrated along the curve, imposes a regularization effect like snakes. We explore the relation between the maximum curvature along the resulting contour and the potential generated from the image. The method is capable to close contours, given only one point on the objects' boundary by using a topology-based saddle search routine. We show examples of our method applied to real aerial and medical images. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY NATL LAB, BERKELEY, CA 94720 USA. RP UNIV PARIS 09, CEREMADE, CNRS, URA 749, PL DU MARECHAL DE LATTRE DE TASSIGNY, F-75775 PARIS 16, FRANCE. NR 68 TC 352 Z9 366 U1 2 U2 20 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-5691 EI 1573-1405 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD AUG PY 1997 VL 24 IS 1 BP 57 EP 78 DI 10.1023/A:1007922224810 PG 22 WC Computer Science, Artificial Intelligence SC Computer Science GA XV644 UT WOS:A1997XV64400004 ER PT J AU He, XY AF He, XY TI Error analysis for the interpolation-supplemented lattice-Boltzmann equation scheme SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article; Proceedings Paper CT 6th International Conference on Discrete Models for Fluid Mechanics CY AUG 26-28, 1996 CL BOSTON UNIV, CTR COMPUTAT SCI, BOSTON, MA HO BOSTON UNIV, CTR COMPUTAT SCI DE lattice-Boltzmann equation; non-uniform grid; numerical error ID NAVIER-STOKES EQUATION; BGK MODELS; SIMULATION AB The numerical error of the interpolation-supplemented lattice-Boltzmann equation (ISLBE) scheme is theoretically analyzed. The ISLBE is proved to recover the Navier-Stokes equation as long as a second order interpolation scheme is used and the dow domain is appropriately discretized. Using a linear interpolation scheme will inevitably generate the numerical diffusivity and viscosity, making the ISLBE scheme unable to simulate the Navier-Stokes equation correctly. The analysis is consistent with previous numerical experiments. RP He, XY (reprint author), LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,MS B213,LOS ALAMOS,NM 87545, USA. NR 20 TC 12 Z9 12 U1 0 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 AUG PY 1997 VL 8 IS 4 BP 737 EP 745 DI 10.1142/S012918319700062X PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA YE900 UT WOS:A1997YE90000009 ER PT J AU Huang, J Xu, F Vallieres, M Feng, DH Qian, YH Fryxell, B Strayer, MR AF Huang, J Xu, F Vallieres, M Feng, DH Qian, YH Fryxell, B Strayer, MR TI A thermal LBGK model for large density and temperature differences SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article; Proceedings Paper CT 6th International Conference on Discrete Models for Fluid Mechanics CY AUG 26-28, 1996 CL BOSTON UNIV, CTR COMPUTAT SCI, BOSTON, MA HO BOSTON UNIV, CTR COMPUTAT SCI DE hydrodynamics; Boltzmann equation; BGK model ID EQUATIONS AB We present a new lattice-Boltzmann method for hydrodynamic simulations, which is capable of handling very large density and temperature gradients. Unlike other LBGK models, the discrete velocities we used center at the local mean Bow velocity, and their values vary according to the local temperature. The adiabatic index of the gas can be easily controlled by a parameter. C1 COLUMBIA UNIV,DEPT APPL PHYS,NEW YORK,NY 10027. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP Huang, J (reprint author), DREXEL UNIV,DEPT PHYS,PHILADELPHIA,PA 19104, USA. NR 10 TC 17 Z9 17 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 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD AUG PY 1997 VL 8 IS 4 BP 827 EP 841 DI 10.1142/S0129183197000710 PG 15 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA YE900 UT WOS:A1997YE90000018 ER PT J AU Luo, LS AF Luo, LS TI Symmetry breaking of flow in 2D symmetric channels: Simulations by lattice-Boltzmann method SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article; Proceedings Paper CT 6th International Conference on Discrete Models for Fluid Mechanics CY AUG 26-28, 1996 CL BOSTON UNIV, CTR COMPUTAT SCI, BOSTON, MA HO BOSTON UNIV, CTR COMPUTAT SCI DE lattice-Boltzmann and lattice-BGK methods; symmetry breaking; flow in 2D symmetric channel with expansion ID NAVIER-STOKES EQUATION; SUDDEN-EXPANSION; GAS AUTOMATA AB In this paper, a numerical study of nonlinear flow phenomena in two-dimensional symmetric channels using the lattice-Boltzmann equation method is presented. The results are compared with both experimental results and other numerical results using some traditional methods. Comparisons are found to be quantitatively accurate. C1 LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,THEORET T DIV,LOS ALAMOS,NM 87545. RP Luo, LS (reprint author), NASA,LANGLEY RES CTR,ICASE,MAIL STOP 403,6 N DRYDEN ST,BLDG 1298,HAMPTON,VA 23681, USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 22 TC 20 Z9 22 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 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD AUG PY 1997 VL 8 IS 4 BP 859 EP 867 DI 10.1142/S0129183197000734 PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA YE900 UT WOS:A1997YE90000020 ER PT J AU Smoot, GF AF Smoot, GF TI Cosmology with the CMB SO INTERNATIONAL JOURNAL OF MODERN PHYSICS D LA English DT Article; Proceedings Paper CT Inauguration Conference of Asia-Pacific-Center-for-Theoretical-Physics CY JUN 04-10, 1996 CL SEOUL, SOUTH KOREA SP Asia Pacific Ctr Theoret Phys ID DIFFERENTIAL MICROWAVE RADIOMETER; COSMIC-BACKGROUND-RADIATION; DMR SKY MAPS; ANGULAR POWER SPECTRUM; COBE DMR; TEMPERATURE-FLUCTUATIONS; EXTRAGALACTIC OBJECTS; STATISTICAL-ANALYSIS; 1ST-YEAR MAPS; ANISOTROPY AB The cosmic microwave background (CMB) radiation provides a means to test the standard model of cosmology and determine its parameters with precision. Cosmology has made a great step forward with the observations and discoveries of the COBE satellite. These were followed with a series of observations and progress via balloon-borne and ground-based instrumentation. Now NASA and ESA have selected and approved new space missions: MAP and COBRAS/SAMBA (now named Planck) which may nearly reach the full potential of CMB observations. RP Smoot, GF (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BLDG 50-205,BERKELEY,CA 94720, USA. NR 94 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-2718 J9 INT J MOD PHYS D JI Int. J. Mod. Phys. D PD AUG PY 1997 VL 6 IS 4 BP 377 EP 391 DI 10.1142/S0218271897000224 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YH403 UT WOS:A1997YH40300001 ER PT J AU Li, S Eastman, JA Vetrone, JM Foster, CM Newnham, RE Cross, LE AF Li, S Eastman, JA Vetrone, JM Foster, CM Newnham, RE Cross, LE TI Dimension and size effects in ferroelectrics SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article DE nanostructured ferroelectrics; size effect; susceptibility; anisotropy ID DRIVEN PHASE-TRANSITION; LANDAU THEORY; DIELECTRIC SUSCEPTIBILITY; THIN-FILMS; POLARIZATION; PARTICLES; TEMPERATURE; MODES AB The characteristic sizes of perovskite ferroelectrics have been examined by mean-field theory in a three dimensional base, leading to a detailed evaluation of the ultimate limits of physical sizes in nanostructured ferroelectrics with the stable polar phase in situations where the influence of depolarizing field can be neglected. Consequently, the dielectric susceptibility of nanostructured ferroelectrics is also derived for a three dimensional case. The size dependencies on the phase transition temperatures of perovskite ferroelectris, such as BaTiO3, PbTiO3: and Pb(Zr0.5Ti0.5)O-3, are calculated by considering crystallographic anisotropy. In addition we have numerically evaluated the dielectric coefficient of Pb(Mg, Nb)O-3 near the Curie temperature range based on its microstructure. C1 PENN STATE UNIV,MAT RES LAB,UNIVERSITY PK,PA 16802. RP Li, S (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 54 TC 91 Z9 96 U1 1 U2 21 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD AUG PY 1997 VL 36 IS 8 BP 5169 EP 5174 DI 10.1143/JJAP.36.5169 PG 6 WC Physics, Applied SC Physics GA XW343 UT WOS:A1997XW34300029 ER PT J AU Kenchington, HS Eisenhauer, JL Green, JAS AF Kenchington, HS Eisenhauer, JL Green, JAS TI A technology roadmap for the US aluminum industry SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article C1 US DEPT ENERGY,OFF IND TECH,WASHINGTON,DC 20585. NR 13 TC 2 Z9 2 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD AUG PY 1997 VL 49 IS 8 BP 18 EP 21 DI 10.1007/BF02914392 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA XP788 UT WOS:A1997XP78800010 ER PT J AU Labaune, C Baldis, HA Schifano, E Tikhonchuk, VT AF Labaune, C Baldis, HA Schifano, E Tikhonchuk, VT TI New issues on Stimulated Brillouin Scattering in a laser-produced plasma SO JOURNAL DE PHYSIQUE III LA English DT Article ID HOT-SPOTS; WAVES AB Good agreement between Stimulated Brillouin Scattering (SBS) measurements and the convective theory of SBS in randomly distributed speckles has been achieved thanks to recent progress in both the experimental and the theoretical parts. Modification of SBS in presence of a secondary interaction beam demonstrates the sensitivity of SBS to initial ion density fluctuations in the plasma. C1 LAWRENCE LIVERMORE NATL LAB,INST LASER SCI & APPLICANT,LIVERMORE,CA 94550. PN LEBEDEV PHYS INST,MOSCOW 117924,RUSSIA. RP Labaune, C (reprint author), ECOLE POLYTECH,CNRS,LAB UTILISAT LASERS INTENSES,F-91128 PALAISEAU,FRANCE. NR 17 TC 1 Z9 1 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4320 J9 J PHYS III JI J. Phys. III PD AUG PY 1997 VL 7 IS 8 BP 1729 EP 1734 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Fluids & Plasmas SC Materials Science; Physics GA XQ689 UT WOS:A1997XQ68900007 ER PT J AU Chhabildas, LC Furnish, MD Grady, DE AF Chhabildas, LC Furnish, MD Grady, DE TI Impact of alumina rods - A computational and experimental study SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID VELOCITIES; KM/S AB Gas gun experiments combined with velocity interferometric techniques have been used to experimentally determine the loading behavior of a Coors-AD995 alumina rod 19 mm in diameter by either 74 mm or 151 mm in length. Graded-density materials were used to impact both bare and sleeved alumina rods, while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments and CTH calculations will demonstrate a unique feature of this novel test methodology: (1) a time-dependent stress pulse generated during impact allows for a smooth and efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between those available from split Hopkinson bar and shock-loading techniques and are not achieved easily by either one of these techniques. C1 APPL RES ASSOCIATES INC,ALBUQUERQUE,NM 87110. RP Chhabildas, LC (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 12 TC 5 Z9 5 U1 1 U2 2 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 137 EP 143 DI 10.1051/jp4:1997326 PG 7 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200027 ER PT J AU Staudhammer, KP AF Staudhammer, KP TI Enhanced diffusion in shock activated Be-Al interfaces SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT AB Enhanced diffusion of aluminum in shock activated beryllium has been observed. Cylindrical samples of aluminum coated beryllium rods were axisymetrically loaded up to 40 Cpa and a total residual strain of up to 6.7%. The defect microstructure produced by both the shock wave and strain enabled the transport of aluminum in beryllium to exceed its equilibrium solid state saturation. This ''super saturated'' aluminum, upon heating exsolves out at relatively low temperatures and forms very strong, interfaces with pressure mated components. RP Staudhammer, KP (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,POB 1663,LOS ALAMOS,NM 87545, USA. NR 8 TC 0 Z9 0 U1 2 U2 2 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 361 EP 366 DI 10.1051/jp4:1997363 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200064 ER PT J AU Majta, J Zurek, A Pietrzyk, M AF Majta, J Zurek, A Pietrzyk, M TI The effect of deformation in the two-phase region of C-Mn and microalloyed steels on the mechanical behaviour of the resulting structure SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT AB The paper presents results of experimental research and a model implementation of hot deformation process in the two-phase region for microalloyed and plain carbon steels. Hot compression tests were employed to determin the behavior of deformed steel over a range of strain rates (1 x 10(-3) - 2.5 x 10(3) s(-1)) and temperatures (650 - 1050 degrees C). The hot deformation conditions during the test were simulated using Finite Element Method. The thermomechanical history of the material is consequently integrated in the simulation. The investigation was focused on the case when the last deformation takes place in the two phase or ferrite region. Such deformed material was investigated to obtain the microstructure development and its influence for mechanical properties in final product. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Majta, J (reprint author), STANISLAW STASZIC UNIV MIN & MET,FAC MET & MAT SCI,PL-30059 KRAKOW,POLAND. NR 6 TC 7 Z9 7 U1 0 U2 0 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 397 EP 402 DI 10.1051/jp4:1997369 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200070 ER PT J AU Gray, GT AF Gray, GT TI Influence of strain rate and temperature on the structure. Property behavior of high-purity titanium SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID SLIP AB The effect of strain rate, temperature, grain size, and texture on the substructure and mechanical response of high-purity polycrystalline titanium is presented. The compressive stress-strain response of 20 and 240 mu m grain size high-purity Ti was found to depend on both the applied strain rate; 0.001 less than or equal to (epsilon) over dot less than or equal to 7500 s(-1), and the test temperature; 77 less than or equal to T less than or equal to 873 K. The rate of strain hardening in Ti is seen to increase with increasing. strain rate. The substructure of high-purity Ti deformed at high-strain-rate or quasi-statically at 77K displayed a higher incidence of deformation twinning than during quasi-static deformation at 298K. RP Gray, GT (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 20 TC 34 Z9 34 U1 0 U2 9 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 423 EP 428 DI 10.1051/jp4:1997373 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200074 ER PT J AU Cline, CF Jacobson, L Reaugh, JE AF Cline, CF Jacobson, L Reaugh, JE TI Dynamic yield strength of a zirconium base metallic glass SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID ALLOY AB Taylor anvil tests in the reverse ballistic mode have been carried out to determine the dynamic yield strength of a Zr 62.6 w/o Cu 13.23, Ti 11.01, Ni 9.77, and Be 3.38 metallic glass. Scanning electron microscopy has been utilized to evaluate the details of the rod and anvil interface after impact. Computer simulations have also been carried out to interpret and confirm the results and conclusions. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Cline, CF (reprint author), LAWRENCE LIVERMORE NATL LAB,PHYS & SPACE TECHNOL DIRECTORATE,LIVERMORE,CA 94550, USA. NR 8 TC 3 Z9 3 U1 0 U2 2 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 493 EP 498 DI 10.1051/jp4:1997385 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200086 ER PT J AU Gray, GT Blumenthal, WR Trujillo, CP Carpenter, RW AF Gray, GT Blumenthal, WR Trujillo, CP Carpenter, RW TI Influence of temperature and strain rate on the mechanical behavior of Adiprene L-100 SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID HOPKINSON PRESSURE BAR; POLYMERS AB The effect of sample thickness, strain rate, and temperature on the mechanical response of Adiprene-L100 is presented. The compressive stress-strain response of Adiprene-L100 was found to depend on both the applied strain rate; 0.001 less than or equal to (epsilon) over dot less than or equal to 7000 s(-1), and the test temperature at high-rate; 77 less than or equal to T less than or equal to 298 K. Due to the slow, dispersive wave propagation in Adiprene-L100, thinner sample thicknesses are needed to assure uniform, uniaxial stress conditions within Hopkinson Bar samples; the optimal sample thickness being dependent on test temperature. Decreasing temperature from 298 to 77K at 3000 s(-1) was found to increase the maximum flow stress in Adiprene-L100 from 10 to similar to 210 MPa. RP LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 13 TC 44 Z9 44 U1 0 U2 4 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 523 EP 528 DI 10.1051/jp4:1997390 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200091 ER PT J AU Murphy, MJ Lassila, DH AF Murphy, MJ Lassila, DH TI Modeling and evaluation of HE driven shock effects in copper with the MTS model SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID MECHANICAL THRESHOLD STRESS; STRAIN RATES AB Many experimental studies have investigated the effect of shock pressure on the post-shock mechanical properties of OFHC copper. These studies have shown that significant hardening occurs during shock loading due to dislocation processes and twinning. It has been demonstrated that when an appropriate initial value of the Mechanical Threshold Stress (MTS) is specified, the post-shock flow stress of OFE copper is well described by relationships derived independently for unshocked materials. In this study we consider the evolution of the MTS during HE driven shock loading processes and the effect on the subsequent flow stress of the copper. An increased post shock flow stress results in a higher material temperature due to an increase in the plastic work. An increase in temperature leads to thermal softening which reduces the flow stress. These coupled effects will determine if there is melting in a shaped charge jet or a necking instability in an EFP liner. The critical factor is the evolution path followed combined with the ''current'' temperature, plastic strain, and strain rate. Preliminary studies indicate that in simulations of HE driven shock processes with very high resolution zoning, the MTS saturates because of the rate dependence in the evolution law. On going studies are addressing this and other issues with the goal of developing a version of the MTS model that treats HE driven shock loading, temperature, strain, and rate effects apriori. RP Murphy, MJ (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 19 TC 1 Z9 1 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 655 EP 661 DI 10.1051/jp4:19973112 PG 7 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200113 ER PT J AU Clancy, SP Burkett, MW Maudlin, PJ AF Clancy, SP Burkett, MW Maudlin, PJ TI Modeling anisotropic plasticity: Eulerian hydrocode applications of high strain-rate deformation processes SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID STRESS AB Previously developed constitutive models and solution algorithms for anisotropic elastoplastic material strength are implemented in the two-dimensional MESA hydrodynamics code. Quadratic yield functions fitted from polycrystal simulations for a metallic hexagonal-close-packed structure are utilized. An associative flow strength formulation incorporating these yield functions is solved using a geometric normal return method. A stretching rod problem is selected to investigate the effects of material anisotropy on a tensile plastic instability (necking). The rod necking rate and topology are compared for MESA simulations performed for both isotropic and anisotropic cases utilizing the Mechanical Threshold Stress flow stress model. RP Clancy, SP (reprint author), LOS ALAMOS NATL LAB,MS F663,LOS ALAMOS,NM 87545, USA. NR 10 TC 3 Z9 3 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 735 EP 740 DI 10.1051/jp4:19973125 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200126 ER PT J AU Chen, SR Gray, GT AF Chen, SR Gray, GT TI Influence of twinning on the constitutive responses of Zr: Experiments and modeling SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID STRAIN-RATE DEFORMATION; LOW-TEMPERATURE; BEHAVIOR; TANTALUM; STRESS; ALLOYS AB The stress-strain response of Zr due to twinning is distinctly different from that due to slip as a function of temperature and strain rate. When the applied stress is lower than the transition stress, dislocation slip is the dominant deformation mechanism. The traditional MTS model is shown to adequately represent the constitutive behavior of Zr. Above the transition stress twinning becomes the dominant deformation mechanism where the flow stress increases linearly with strain. In this regime the rate-dependent strain hardening can be described by equations based on thermal activation theory that are very similar to the formula used in the MTS model. RP Chen, SR (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 11 TC 2 Z9 2 U1 3 U2 5 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 741 EP 746 DI 10.1051/jp4:19973126 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200127 ER PT J AU Clements, BE Johnson, JN Addessio, FL Hixson, RS AF Clements, BE Johnson, JN Addessio, FL Hixson, RS TI Impact produced stress waves in composites SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT AB The Nonhomogenized Dynamic Method of Cells (NHDMOC) is used to study the propagation of stress waves through laminates. The accuracy of the theory is tested by applying it to a plate-impact experiment and checking its ability to resolve a propagating shock wave front. The theory is then compared to Lagrangian hydrodynamic calculations, where it is found that the NHDMOC consistently requires less fine spatial and temporal grids, and less artificial viscosity to control numerical noise. The theory is then used to treat the impact of an epoxy-graphite bilaminate. When the viscoelastic properties of the epoxy are accounted for, the theory agrees well with the experiment. RP Clements, BE (reprint author), LOS ALAMOS NATL LAB,GRP T1,MSB 221,LOS ALAMOS,NM 87545, USA. NR 3 TC 5 Z9 5 U1 0 U2 2 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 767 EP 772 DI 10.1051/jp4:19973130 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200131 ER PT J AU Tonks, DL Thissell, WR Zurek, AK Hixson, R AF Tonks, DL Thissell, WR Zurek, AK Hixson, R TI Quantitative analysis of damage clustering and void linking for spallation modeling in tantalum SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID DUCTILE FRACTURE AB In a companion paper in this volume by Zurek et al, micrographs of incipient spallation damage in commercial purity tantalum were numerically analyzed using image analysis techniques. Void sizes, locations, and overall porosity were measured and graphically presented. In this paper, we extend this analysis to include void clusters and examine the correlation between cluster size and the ranges of local instabilities between voids visible in the micrographs. We discuss the implications for spallation modeling. RP Tonks, DL (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 3 TC 10 Z9 10 U1 1 U2 2 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 841 EP 846 DI 10.1051/jp4:19973142 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200143 ER PT J AU Zurek, AK Thissell, WR Tonks, DL Hixson, R Addessio, F AF Zurek, AK Thissell, WR Tonks, DL Hixson, R Addessio, F TI Quantification of damage evolution for a micromechanical model of ductile fracture in spallation of tantalum SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 5th International Conference on Mechanical and Physical Behaviour of Materials under Dynamics Loading (EURODYMAT 97) CY SEP 22-26, 1997 CL TOLEDO, SPAIN SP Univ Carlos III Madrid, Assoc DYMAT ID SOLIDS; RELEASE AB We present quantification of micromechanical features such as voids that comprise the ductile fracture obtained under uniaxial strain condition in a spall test of commercial purity tantalum. Two evolutionary parameters of ductile fracture void formation are quantified: (i) the void volume fraction (porosity) and its distribution with respect to the distance from the main spall fracture plane, and (ii) void diameter distribution. The results complement the discussion of the implications of void clustering and linking for micromechanical modeling of ductile fracture as presented in a paper by D.L. Tonks et al. in this volume. RP Zurek, AK (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 29 TC 18 Z9 19 U1 1 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD AUG PY 1997 VL 7 IS C3 BP 903 EP 908 DI 10.1051/jp4:19973152 PG 6 WC Physics, Multidisciplinary SC Physics GA YA512 UT WOS:A1997YA51200153 ER PT J AU Spooner, S Wang, XL AF Spooner, S Wang, XL TI Diffraction peak displacement in residual stress samples due to partial burial of the sampling volume SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB Near-surface measurement of residual strain and stress with neutron scattering complements and extends the surface residual stress measurements by X-ray diffraction. However, neutron diffraction measurements near surfaces are sensitive to scattering volume alignment, neutron beam wavelength spread and beam collimation and, unless properly understood, can give large fictitious strains. An analytic calculation and a numerical computation of neutron diffraction peak shifts due to partial burial of the sampling volume have been made and are compared with experimental measurement. Peak shifts in a strain-free nickel sample were determined for conditions where the sample surface is displaced so that the scattering gage volume is partially buried in the sample. The analytic and numerically computed peak shifts take into account the beam collimation, neutron source size, monochromator crystal mosaic spread and the collection of diffracted intensity with a linear position-sensitive counter. RP Spooner, S (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Wang, Xun-Li/C-9636-2010 OI Wang, Xun-Li/0000-0003-4060-8777 NR 6 TC 27 Z9 27 U1 1 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD AUG 1 PY 1997 VL 30 BP 449 EP 455 DI 10.1107/S0021889897000174 PN 4 PG 7 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA XW118 UT WOS:A1997XW11800005 ER PT J AU VonDreele, RB AF VonDreele, RB TI Quantitative texture analysis by Rietveld refinement SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID X-RAY; PREFERRED ORIENTATION; POWDER DIFFRACTION; MODEL AB A generalized spherical-harmonic description of the texture for polycrystalline materials has been implemented in a multiple-phase/multiple-data-set Rietveld refinement code. It has been tested using two sets of neutron time-of-flight data taken from a standard calcite sample previously used for a round-robin study [Wenk (1991). J. Appl. Cryst. 24, 920-927] and has been shown to give similar texture results as those obtained from individual pole figures. Simultaneous refinement of the calcite crystal structure including anisotropic thermal parameters gives results essentially identical to a recent single-crystal X-ray study. RP VonDreele, RB (reprint author), LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,MS H805,LOS ALAMOS,NM 87545, USA. NR 23 TC 304 Z9 304 U1 3 U2 50 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD AUG 1 PY 1997 VL 30 BP 517 EP 525 DI 10.1107/S0021889897005918 PN 4 PG 9 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA XW118 UT WOS:A1997XW11800018 ER PT J AU Snodgrass, JW AF Snodgrass, JW TI Temporal and spatial dynamics of beaver-created patches as influenced by management practices in a south-eastern North American landscape SO JOURNAL OF APPLIED ECOLOGY LA English DT Article DE Castor canadensis; catchment management; forested streams; riparian habitat ID CLASSIFICATION-SYSTEM; CASTOR-CANADENSIS; NEWFOUNDLAND; COLONIES; STREAMS; BASIN AB 1. Beavers create habitat diversity across catchment landscapes by impounding small streams. This increased habitat diversity leads to increased species richness of plants and animals in small streams. As managers work to balance conflicting management goals (e.g. protection of timber and human structures versus maintenance of biological diversity) the influence of beaver population management practices on habitat availability needs to be assessed. Two questions of initial concern are: (i) how do different levels of management influence the availability of beaver created habitats and (ii) do relationships developed in one region apply to other regions? 2. To address these questions, historical aerial photography was used to determine the extent and rate of impoundment of streams by beavers Castor canadensis over a 77 000 ha south-eastern North American landscape during a 40-year period of beaver population recovery. Between 1950 and 1983, beaver populations were protected from trapping and hunting. From 1983 to the present, beaver numbers were reduced by fatal trapping, to protect roads, railroads and timber. Trapped beavers were assigned to specific colonies associated with beaver-created patches in the landscape, and growth rates and size after management of individual patches receiving different levels of management were compared. Results from this study were also compared with previous studies conducted in Minnesota, USA. 3, Growth rate, patch size following management and the composition of habitat types within patches were not related to management activity, suggesting that the levels of management used in this study did not influence the temporal dynamics of beaver-created patches. The extent and rate of beaver impoundment on the southeastern Upper Coastal Plain of North America was less than that reported from central North American landscapes over comparable periods. 4, These results have the following implications for management: (i) management activities should be monitored on a regional basis; (ii) conflicting beaver population management goals should be addressed, evaluated and balanced; and (iii) beavers do not present a threat to flowing-water species in south-eastern North America and need not be controlled for this reason. C1 RUTGERS STATE UNIV,DIV LIFE SCI,PISCATAWAY,NJ 08855. RUTGERS STATE UNIV,ENVIRONM HLTH INST,PISCATAWAY,NJ 08855. RP Snodgrass, JW (reprint author), UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. RI Snodgrass, Joel/C-5288-2016; OI Snodgrass, Joel/0000-0002-4436-8750 NR 29 TC 37 Z9 39 U1 2 U2 19 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0021-8901 J9 J APPL ECOL JI J. Appl. Ecol. PD AUG PY 1997 VL 34 IS 4 BP 1043 EP 1056 DI 10.2307/2405293 PG 14 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA XT348 UT WOS:A1997XT34800019 ER PT J AU Allwine, KJ Bian, XD Whiteman, CD Thistle, HW AF Allwine, KJ Bian, XD Whiteman, CD Thistle, HW TI VALDRIFT - A valley atmospheric dispersion model SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TEMPERATURE INVERSIONS; MOUNTAIN VALLEY; TRANSPORT; TRACER; AIRCRAFT; FIELD; WINDS AB VALDRIFT (valley drift) is a valley atmospheric transport, diffusion, and deposition model. The model is phenomenological-that is, the dominant meteorological processes governing the behavior of the valley atmosphere are formulated explicitly in the model, although in a highly parameterized fashion. The key meteorological processes treated are 1) nonsteady and nonhomogeneous along-valley winds and turbulent diffusivities, 2) convective boundary layer growth, 3) inversion descent, and 4) nocturnal temperature inversion breakup. The model is applicable under relatively cloud-free, undisturbed synoptic conditions in which the winds in the valley are predominantly along the valley's axis. The model is configured to operate through one diurnal cycle for a single narrow valley. The inputs required are the valley topographic characteristics, pollutant release rate as a function of time and space, wind speed and direction as functions of time measured at one height, lateral and vertical turbulent eddy diffusivities as functions of stability, and the valley temperature inversion characteristics at sunrise. The outputs are three-dimensional concentration fields and ground-level deposition fields as functions of time. The scientific foundations of VALDRIFT are given in this paper along with a brief discussion of the model inputs and outputs. Air concentrations estimated by VALDRIFT compare favorably with results from a tracer experiment conducted in a deep mountain valley. C1 PACIFIC NW NATL LAB,RICHLAND,WA. US FOREST SERV,USDA,MISSOULA,MT. RP Allwine, KJ (reprint author), ALLWINE ENVIRONM SERV,1763 DULUTH ST,RICHLAND,WA 99352, USA. NR 31 TC 6 Z9 6 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD AUG PY 1997 VL 36 IS 8 BP 1076 EP 1087 DI 10.1175/1520-0450(1997)036<1076:VAVADM>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN978 UT WOS:A1997XN97800012 ER PT J AU Asay, BW Laabs, GW Henson, BF Funk, DJ AF Asay, BW Laabs, GW Henson, BF Funk, DJ TI Speckle photography during dynamic impact of an energetic material using laser-induced fluorescence SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTERFEROMETRY; MECHANICS; FRINGES AB Laser and white light speckle photography have been used to observe surface displacement in a number of materials and over a varied range of strain rates. However, each suffers from limitations. We have developed a novel application of speckle photography in very difficult environments by using laser-induced fluorescence to generate the speckle pattern. This permits confinement of the free surface without undue degradation of the correlation upon which speckle methods are based. We have applied this method to measure the surface displacement of a reactive material during dynamic deformation at moderate strain rates. Conventional methods were tried but were unsuccessful, necessitating a novel approach. To the best of our knowledge, neither high-speed laser nor white light speckle photography has been performed using energetic materials. These measurements are very difficult because of the low material strength (yield strength similar to 8-80 MPa), and because significant out-of-plane motion and surface disruption occur during fracture, and early during the deformation process. We report results from experiments in which these major problems have been overcome. (C) 1997 American Institute of Physics. RP Asay, BW (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 20 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 1 PY 1997 VL 82 IS 3 BP 1093 EP 1099 DI 10.1063/1.365876 PG 7 WC Physics, Applied SC Physics GA XP106 UT WOS:A1997XP10600021 ER PT J AU Thadhani, NN Graham, RA Royal, T Dunbar, E Anderson, MU Holman, GT AF Thadhani, NN Graham, RA Royal, T Dunbar, E Anderson, MU Holman, GT TI Shock-induced chemical reactions in titanium-silicon powder mixtures of different morphologies: Time-resolved pressure measurements and materials analysis SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID COMBUSTION SYNTHESIS; CONSOLIDATION; SILICIDES; COMPRESSION AB The response of porous titanium (Ti) and silicon (Si) powder mixtures with small, medium, and coarse particle morphologies is studied under high-pressure shock loading, employing postshock materials analysis as well as nanosecond, time-resolved pressure measurements. The objective of the work was to provide an experimental basis for development of models describing shock-induced solid-state chemistry. The time-resolved measurements of stress pulses obtained with piezoelectric polymer (poly-vinyl-di-flouride) pressure gauges provided extraordinary sensitivity for determination of rate-dependent shock processes. Both techniques showed clear evidence for shock-induced chemical reactions in medium-morphology powders, while fine and coarse powders showed no evidence for reaction. It was observed that the medium-morphology mixtures experience simultaneous plastic deformation of both Ti and Si particles. Fine morphology powders show particle agglomeration, while coarse Si powders undergo extensive fracture and entrapment within the plastically deformed Ti; such processes decrease the propensity for initiation of shock-induced reactions. The change of deformation mode between fracture and plastic deformation in Si powders of different morphologies is a particularly critical observation. Such a behavior reveals the overriding influence of the shock-induced, viscoplastic deformation and fracture response, which controls the mechanochemical nature of shock-induced solid-state chemistry. The present work in conjunction with our prior studies, demonstrates that the initiation of chemical reactions in shock compression of powders is controlled by solid-state mechanochemical processes, and cannot be qualitatively or quantitatively described by thermochemical models. (C) 1997 American Institute of Physics. C1 TOME GRP,TOME,NM 87031. NEW MEXICO INST MIN & TECHNOL,DEPT MAT & MET ENGN,SOCORRO,NM 87801. SANDIA NATL LABS,DEPT 1152,ALBUQUERQUE,NM 87185. RP Thadhani, NN (reprint author), GEORGIA INST TECHNOL,SCH MAT SCI & ENGN,ATLANTA,GA 30332, USA. NR 73 TC 81 Z9 83 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 1 PY 1997 VL 82 IS 3 BP 1113 EP 1128 DI 10.1063/1.365878 PG 16 WC Physics, Applied SC Physics GA XP106 UT WOS:A1997XP10600023 ER PT J AU Zhu, YT Lowe, TC Asaro, RJ AF Zhu, YT Lowe, TC Asaro, RJ TI Assessment of the theoretical basis of the Rule of Additivity for the nucleation incubation time during continuous cooling SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID AUSTENITE-PEARLITE TRANSFORMATION; C-X ALLOYS; PROEUTECTOID FERRITE; ISOTHERMAL TRANSFORMATION; CARBON-STEEL; FE-C; KINETICS; PRECIPITATION; TEMPERATURES; PRINCIPLE AB The rule of additivity was first proposed by Scheil and Steinberg for predicting the incubation time fpr nucleation of solid phases during continuous-cooling phase transformations, and has since been widely used for both the nucleation incubation and the entire process of phase transformation. While having been successfully used to calculate the transformed volume fraction during continuous cooling in many steel alloy systems, there is experimental evidence that shows rule of additivity to be invalid for describing the incubation time for nucleation. Attempts to prove the validity of the rule of additivity for the incubation time have not met with much success, and much confusion still exists about its applicability to the incubation time. This article investigates the additivity of the consumption of the incubation time for nucleation during continuous cooling through an analysis leased upon classical nucleation theory. It is rigorously demonstrated that the rule of additivity is invalid for the incubation time for nucleation. However, in practice, the relative error caused by using the rule of additivity could be very small in many cases due to the resolution limit of current experimental techniques. The present theory provides an explanation for the failure of the rule of additivity in predicting the incubation time for nucleation during continuous cooling. (C) 1997 American Institute of Physics. C1 UNIV CALIF SAN DIEGO,DEPT APPL MECH & ENGN SCI,LA JOLLA,CA 92093. RP Zhu, YT (reprint author), LOS ALAMOS NATL LAB,DEPT MAT SCI & TECHNOL,MS G755,LOS ALAMOS,NM 87545, USA. RI Zhu, Yuntian/B-3021-2008 OI Zhu, Yuntian/0000-0002-5961-7422 NR 69 TC 7 Z9 7 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 1 PY 1997 VL 82 IS 3 BP 1129 EP 1137 DI 10.1063/1.365879 PG 9 WC Physics, Applied SC Physics GA XP106 UT WOS:A1997XP10600024 ER PT J AU Wilson, AK Blum, CA Bhattacharyya, MH AF Wilson, AK Blum, CA Bhattacharyya, MH TI The role of metallothionein in cadmium-induced bone resorption. SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1997 VL 12 SU 1 BP F256 EP F256 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XP627 UT WOS:A1997XP62700746 ER PT J AU Freeman, SPHT Allen, LH Siekmann, JH Waterman, J Heaney, RP AF Freeman, SPHT Allen, LH Siekmann, JH Waterman, J Heaney, RP TI The detection in archived human samples of inadvertently administered Ca-41 tracer. SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. UNIV CALIF DAVIS,DAVIS,CA. CREIGHTON UNIV,OMAHA,NE 68178. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1997 VL 12 SU 1 BP T493 EP T493 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XP627 UT WOS:A1997XP62700487 ER PT J AU Lane, NE Haupt, DL Modin, G Kinney, JH AF Lane, NE Haupt, DL Modin, G Kinney, JH TI The correlation between trabecular bone structural variables obtained by 3D and 2D methods. SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,SAN FRANCISCO,CA 94143. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. CREIGHTON UNIV,OMAHA,NE 68178. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1997 VL 12 SU 1 BP T485 EP T485 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XP627 UT WOS:A1997XP62700479 ER PT J AU WengSieh, Z Gronsky, R Bell, AT AF WengSieh, Z Gronsky, R Bell, AT TI Microstructural evolution of gamma-alumina-supported Rh upon aging in air SO JOURNAL OF CATALYSIS LA English DT Article ID HIGH-TEMPERATURE OXIDATION; THERMAL-STABILITY; ELECTRON-MICROSCOPY; CATALYST SUPPORTS; SURFACE-AREA; RHODIUM; REDUCTION; RH/AL2O3; TRANSFORMATION; MORPHOLOGY AB Microstructural changes in alumina-supported rhodium catalysts during aging in air at high temperatures were investigated using a combination of high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction. Both constituents, particles and support, undergo structural changes during thermal aging. With increasing aging temperature and time, the support transforms from gamma- to alpha-alumina, and the phase change is accelerated by the presence of rhodium. The rhodium, present initially as 10-Angstrom-diameter metal particles, undergoes oxidation with the formation of a variety of oxide phases, depending on the temperature at which aging has occurred. At 500 degrees C, highly dispersed, raft-like structures are observed. Continued aging at this temperature results in a coarsening of these structures to form three-dimensional particles of high-temperature, high-pressure (HT, HP) orthorhombic Rh2O3. At 850 degrees C, aging causes severe coalescence of the HT, HP orthorhombic Rh2O3 particles, while at 1000 degrees C, RhO2 particles are observed together with large particles of HT, HP orthorhombic Rh2O3. A high Rh binding energy (near 309 eV) is observed using XPS following all aging treatments and may be attributed to either the HT, HP orthorhombic phase or to Rh4+. (C) 1997 Academic Press. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP WengSieh, Z (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 39 TC 72 Z9 72 U1 0 U2 14 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD AUG PY 1997 VL 170 IS 1 BP 62 EP 74 DI 10.1006/jcat.1997.1738 PG 13 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA XR044 UT WOS:A1997XR04400008 ER PT J AU Savargaonkar, N Khanra, BC Pruski, M King, TS AF Savargaonkar, N Khanra, BC Pruski, M King, TS TI Influence of hydrogen chemisorption on the surface composition of Pt-Rh/Al2O3 catalysts - Reply SO JOURNAL OF CATALYSIS LA English DT Letter C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. SAHA INST NUCL PHYS,CALCUTTA 700064,W BENGAL,INDIA. RP Savargaonkar, N (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM ENGN,AMES,IA 50011, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD AUG PY 1997 VL 170 IS 1 BP 213 EP 213 DI 10.1006/jcat.1997.1758 PG 1 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA XR044 UT WOS:A1997XR04400025 ER PT J AU Boonmark, NW Lou, XJ Yang, ZJ Schwartz, K Zhang, JL Rubin, EM Lawn, RM AF Boonmark, NW Lou, XJ Yang, ZJ Schwartz, K Zhang, JL Rubin, EM Lawn, RM TI Modification of apolipoprotein(a) lysine binding site reduces atherosclerosis in transgenic mice SO JOURNAL OF CLINICAL INVESTIGATION LA English DT Article DE lipoprotein; apolipoprotein; lipoprotein(a); fibrin; mouse ID GROWTH-FACTOR-BETA; EXPRESSING HUMAN APOLIPOPROTEIN(A); HUMAN PLASMINOGEN KRINGLE-4; LOW-DENSITY-LIPOPROTEIN; A-I; FIBRIN BINDING; ATHEROGENESIS; ACTIVATION; HETEROGENEITY; INHIBITION AB Lipoprotein(a) contributes to the development of atherosclerosis through the binding of its plasminogen-like apolipoprotein(a) component to fibrin and other plasminogen substrates. Apolipoprotein(a) contains a major lysine binding site in one of its kringle domains, Destruction of this site by mutagenesis greatly reduces the binding of apolipoprotein(a) to lysine and fibrin, Transgenic mice expressing this mutant form of apolipoprotein(a) as well as mice expressing wild-type apolipoprotein(a) have been created in an inbred mouse strain, The wild-type apolipoprotein(a) transgenic mice have a fivefold increase in the development of lipid lesions, as well as a large increase in the focal deposition of apolipoprotein(a) in the aorta, compared with the lysine binding site mutant strain and to nontransgenic littermates. The results demonstrate the key role of this lysine binding site in the pathogenic activity of apolipoprotein(a) in a murine model system. C1 STANFORD UNIV,SCH MED,FALK CARDIOVASC RES CTR,STANFORD,CA 94305. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. FU NHLBI NIH HHS [HL-48638, HL-07708, HL-50590] NR 55 TC 60 Z9 63 U1 1 U2 2 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 SN 0021-9738 J9 J CLIN INVEST JI J. Clin. Invest. PD AUG 1 PY 1997 VL 100 IS 3 BP 558 EP 564 DI 10.1172/JCI119565 PG 7 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA XQ280 UT WOS:A1997XQ28000010 PM 9239402 ER PT J AU Bruinsma, PJ Wang, Y Li, XS Liu, J Smith, PA Bunker, BC AF Bruinsma, PJ Wang, Y Li, XS Liu, J Smith, PA Bunker, BC TI Rheological and solid-liquid separation properties of bimodal suspensions of colloidal gibbsite and boehmite SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE bimodal suspensions; aggregation; rheology; sedimentation; filtration ID VISCOSITY AB Bimodal suspensions of nanometer-sized boehmite particles and micron-sized gibbsite particles in 0.10 M NaNO3 are used as models to gain insight into the physical properties of agglomerating colloidal suspensions containing bimodal distributions of primary particles. Results on the gibbsite-boehmite mixtures show that the presences of small particles in a suspension can have a dramatic impact on the rheological, sedimentation, and filtration characteristics of suspensions of larger particles. Transmission electron micrographs show that boehmite forms a coating on the larger gibbsite particles, The coating provides steric repulsion and reduces the attractive interactions between the larger particles, leading to viscosity decreases and greater densification of sediments and filter cakes. A model has been developed to rationalize observed property changes based on the range of agglomerate structures that can form in mixtures of large and small particles, Results are discussed in the content of the processing of nuclear waste sludges, but are applicable to a wide range of bimodal suspensions, (C) 1997 Academic Press. RP Bruinsma, PJ (reprint author), PACIFIC NW LAB, DEPT MAT SCI,BATELLE BLVD,BOX 999, MAIL STOP K8-93, RICHLAND, WA 99352 USA. NR 20 TC 9 Z9 9 U1 1 U2 10 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD AUG 1 PY 1997 VL 192 IS 1 BP 16 EP 25 DI 10.1006/jcis.1997.5013 PG 10 WC Chemistry, Physical SC Chemistry GA XT784 UT WOS:A1997XT78400002 ER PT J AU Winslow, AM AF Winslow, AM TI Numerical solution of the quasilinear Poisson equation in a nonuniform triangle mesh (Reprinted from the Journal of Computational Physics, vol 1, pg 149-172, 1966) SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Reprint AB A finite-difference method using a nonuniform triangle mesh is described for the numerical solution of the nonlinear two-dimensional Poisson equation del.(lambda del phi) + S = 0, where lambda is a function of phi or its derivatives, S is a function of position, and phi or its normal derivative is specified on the boundary, The finite-difference equations are solved by successive overrelaxation. The triangle mesh, which is constructed numerically by solving Laplace's equation, is easily adapted to nonrectangular boundaries and interfaces, Examples of numerical results are given for the magnetostatic problem with iron, and other possible applications are mentioned. (C) 1967 Academic Press. RP Winslow, AM (reprint author), LAWRENCE RADIAT LAB, LIVERMORE, CA USA. NR 27 TC 17 Z9 18 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG PY 1997 VL 135 IS 2 BP 128 EP 138 DI 10.1006/jcph.1997.5698 PG 11 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700008 ER PT J AU Langdon, AB AF Langdon, AB TI Clouds-in-clouds, clouds-in-cells physics for many-body simulation - Introduction SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Editorial Material RP Langdon, AB (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 8 TC 1 Z9 1 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG PY 1997 VL 135 IS 2 BP 139 EP 140 DI 10.1006/jcph.1997.5763 PG 2 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700009 ER PT J AU Birdsall, CK Fuss, D AF Birdsall, CK Fuss, D TI Clouds-in-clouds, clouds-in-cells physics for many-body plasma simulation (Reprinted from the Journal of Computational Physics, vol 3, pg 494-511, 1969) SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Reprint AB A clouds-interacting-with-clouds, clouds-in-cells method (CIC) is presented for many-body nonlinear plasma problems. Density and force are obtained by assuming that the particles have finite size, are tenuous, and may pass through one another; the particles are thus called clouds. They obey a Coulomb force (similar to 1/r or 1/r(3)) when separated and a linear force (similar to r) when overlapping, allowing simple harmonic oscillations at small separation. CIC is contrasted with the zero-size particle and nearest-grid-point approach, ZSP-NGP. CIC appears to have substantially less unwanted noise than ZSP-NGP and should be more useful in simulating dense plasmas, Initial runs have been encouraging. The methods may find use in other many-body simulations, such as with stars, or with particles in phase space. (C) 1969 Academic Press. C1 UNIV CALIF BERKELEY,ELECT ENGN & COMP SCI DEPT,BERKELEY,CA. RP Birdsall, CK (reprint author), LAWRENCE LIVERMORE NATL LAB,LAWRENCE RADIAT LAB,LIVERMORE,CA 94550, USA. NR 12 TC 20 Z9 22 U1 3 U2 7 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG PY 1997 VL 135 IS 2 BP 141 EP 148 DI 10.1006/jcph.1997.5723 PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700010 ER PT J AU Margolin, LG AF Margolin, LG TI Introduction to ''an arbitrary Lagrangian-Eulerian computing method for all flow speeds'' SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Editorial Material ID FLUX-CORRECTED TRANSPORT; FINITE-ELEMENT METHOD; ALGORITHMS; EQUATIONS; ADVECTION; ERRORS; FLUIDS; MESH RP LOS ALAMOS NATL LAB, POB 1663, LOS ALAMOS, NM 87545 USA. NR 31 TC 66 Z9 70 U1 1 U2 16 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG PY 1997 VL 135 IS 2 BP 198 EP 202 DI 10.1006/jcph.1997.5727 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700017 ER PT J AU Hirt, CW Amsden, AA Cook, JL AF Hirt, CW Amsden, AA Cook, JL TI An arbitrary Lagrangian-Eulerian computing method for all flow speeds (Reprinted from the Journal of Computational Physics, vol 14, pg 227-253, 1974) SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Reprint ID FLUID AB A new numerical technique is presented that has many advantages for obtaining solutions to a wide variety of time-dependent multidimensional fluid dynamics problems. The method uses a finite difference mesh with vertices that may be moved with the fluid (Lagrangian), be held fixed (Eulerian), or be moved in any other prescribed manner, as in the Arbitrary Lagrangian-Eulerian (ALE) technique. In addition, it employs an implicit formulation similar to that of the Implicit Continuous-fluid Eulerian (ICE) technique, making it applicable to flows at all speeds. This paper describes the basic methodology, presents finite difference approximations, and discusses such matters as stability, accuracy, and zoning. In addition, illustrations are included from a number of representative calculations. (C) 1974 Academic Press. RP LOS ALAMOS NATL LAB, POB 1663, LOS ALAMOS, NM 87544 USA. NR 21 TC 119 Z9 137 U1 1 U2 30 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG PY 1997 VL 135 IS 2 BP 203 EP 216 DI 10.1006/jcph.1997.5702 PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700018 ER PT J AU Cramer, SP Ralston, CY Wang, HX Bryant, C AF Cramer, SP Ralston, CY Wang, HX Bryant, C TI Bioinorganic applications of X-ray multiplets - The impact of Theo Thole's work SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE Ni enzymes, hydrogenase; CO dehydrogenase; Ni L-edges; X-ray magnetic circular dichroism ID MAGNETIC CIRCULAR-DICHROISM; ABSORPTION-SPECTRA; SUM-RULES; SPIN; STATE; PLASTOCYANIN; PROBE; IRON; SPECTROSCOPY; FLUORESCENCE AB Prior to the work of Thee Thole and his collaborators, the vast majority of biological X-ray spectroscopy involved either EXAFS or hard X-ray XANES spectroscopy. Thee Thole's ligand field multiplet theory revealed the rich information content of transition metal L-edges, and it helped prompt the first measurements on metalloproteins. His contributions to XMCD also prompted the first low-temperature/high-field experiments on paramagnetic centers in proteins, This paper describes some recent work in biological soft X-ray spectroscopy that was stimulated by Thole's findings, Representative Ni protein absorption spectra are shown, illustrating detection of Ni(I), NL(III), and high-and low-spin Ni(II) in Ni hydrogenase and CO dehydrogenase, New XMCD spectra for Cu in plastocyanin and Fe in a 2Fe ferredoxin are presented. The exciting prospects for soft X-ray absorption and XMCD of metalloproteins are summarized. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Cramer, SP (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616, USA. NR 24 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 AUG PY 1997 VL 86 IS 1-3 BP 175 EP 183 DI 10.1016/S0368-2048(97)00064-9 PG 9 WC Spectroscopy SC Spectroscopy GA XY512 UT WOS:A1997XY51200026 ER PT J AU Biefeld, RM Kurtz, SR Allerman, AA AF Biefeld, RM Kurtz, SR Allerman, AA TI The metalorganic chemical vapor deposition growth of AlAsSb and InAsSb/InAs using novel source materials for infrared emitters SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE InAsSb; lasers; mid-infrared; metalorganic chemical vapor deposition (MOCVD) ID STRAINED-LAYER SUPERLATTICES; PHASE EPITAXIAL-GROWTH; MU-M; LASERS; ALLOYS; ALGASB AB We have grown AlSb and AlAsxSb1-x epitaxial layers by metalorganic chemical vapor deposition (MOCVD) using trimethylamine or ethyldimethylamine alane, triethylantimony, and arsine. These layers were successfully doped p-or n-type using diethylzinc or tetraethyltin, respectively. We examined the growth of AlAsxSb1-x using temperatures of 500 to 600 degrees C, pressures of 65 to 630 Torr, V/III ratios of 1-17, and growth rates of 0.3 to 2.7 mu m/h in a horizontal quartz reactor. We have also grown gain-guided, injection lasers using AlAsSb for optical confinement and a strained InAsSb/InAs multi-quantum well active region using MOCVD. The semi-metal properties of a p-GaAsSb/n-InAs heterojunction are utilized as a source for injection of electrons into the active region of the laser. In pulsed mode, the laser operated up to 210K with an emission wavelength of 3.8-3.9 mu m The dependence of active region composition on wavelength was determined. We also report on the two-color emission of a light-emitting diode with two different active regions to demonstrate multi-stage operation of these devices. RP Biefeld, RM (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 20 TC 8 Z9 8 U1 2 U2 9 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD AUG PY 1997 VL 26 IS 8 BP 903 EP 909 DI 10.1007/s11664-997-0272-8 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA XT946 UT WOS:A1997XT94600004 ER PT J AU Philippacopoulos, AJ AF Philippacopoulos, AJ TI Buried point source in a poroelastic half-space. SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID DYNAMIC GREENS-FUNCTIONS; SCATTERING; PLANE; COMPUTATION; INTEGRALS; INFINITE; RANGE; MEDIA AB The problem under consideration is to determine the motion of a poroelastic half-space produced by a buried point source with arbitrary lime variation. The method followed is to generate the associated Green's functions as a superposition of the singular solution corresponding to the inhomogeneous problem for the whole space plus a contribution representing relevant effects due to the presence of the free surface, The mathematical approach is based on integral transform techniques: Fourier transform with respect to the time and Hankel transform with respect to the space, The Green's functions for the displacement fields (solid and pore fluid motion respectively) show additional integratable singularities arising from Rayleigh poles and by eight branch points resulting from combinations of three radicals containing the three fundamental wave numbers of poroelastic propagation. Recognizing that the branch points and poles are complex valued as a result of dissipation by the skeletal frame as well as viscous dissipation due to the relative motion of the pore fluid with respect to the frame material, integration in the omega-k domain is done along a path that coincides with the real wave-number axis. Such integration is required only for surface contributions to the Green's function, The motion generated by a point source in the poroelastic half-space at an observation distance is synthesized by three direct waves radiating from the source (fast/slow dilatational and a transverse wave) and by a series of waves (nine for the general case) associated with reflections at the free surface (P1P1, P1S, SP1, etc.). The present integral solution gives an idea of the format of an eigenfunction synthesis through expansion of the two vector fields (for the solid and fluid phases) in terms of Hensen eigenvectors. It is shown that the solutions presented in this study reduce to known counterparts of elastodynamics for zero porosity and, in particular, to the classical solution by Pekeris. Finally, The Green's functions for a point source buried in a poroelastic half-space complement those obtained in a recent study for the case of a line source. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. NR 25 TC 22 Z9 25 U1 2 U2 3 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD AUG PY 1997 VL 123 IS 8 BP 860 EP 869 DI 10.1061/(ASCE)0733-9399(1997)123:8(860) PG 10 WC Engineering, Mechanical SC Engineering GA XM218 UT WOS:A1997XM21800013 ER PT J AU Cantrell, KJ Kaplan, DI Gilmore, TJ AF Cantrell, KJ Kaplan, DI Gilmore, TJ TI Injection of colloidal Fe-0 particles in sand with shear-thinning fluids SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID ZERO-VALENT IRON; GROUNDWATER; METALS AB A novel approach to emplacing chemically reactive barriers is the injection of zero-valent iron (Fe-0) colloids into the subsurface. A difficulty encountered in this approach is that the dense Fe-0 colloids (7.6 g/cm(3)) settle out of solution with time, decreasing the distance the colloids can be injected into the subsurface. Studies were conducted to evaluate if several viscous shear-thinning fluids could enhance Fe-0 colloid emplacement in porous media. Aqueous solutions of three nontoxic polymers at different concentrations were investigated: a synthetic high molecular weight polymer [vinyl polymer, (VP)], a biopolymer (gum xanthan, GX), and a cellulose-type polymer (carboxymethyl cellulose, CMC). The use of shear-thinning fluids greatly increases the mobility of the colloidal Fe-0 suspensions in porous media. VP was superior to GX and CMC because the VP suspensions produced the lowest back pressures, resulting in the highest hydraulic conductivities. RP Cantrell, KJ (reprint author), PACIFIC NW LAB, POB 999, MAILSTOP K6-81, RICHLAND, WA 99352 USA. NR 18 TC 39 Z9 40 U1 2 U2 7 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD AUG PY 1997 VL 123 IS 8 BP 786 EP 791 DI 10.1061/(ASCE)0733-9372(1997)123:8(786) PG 6 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XM744 UT WOS:A1997XM74400010 ER PT J AU Schwartz, DT Buehler, MF Christiansen, DX Davis, EJ AF Schwartz, DT Buehler, MF Christiansen, DX Davis, EJ TI In-situ monitoring of electrochemical transport processes in Hanford Grout Vault Soil SO JOURNAL OF HAZARDOUS MATERIALS LA English DT Article DE radiotracer techniques; water electrolysis; soil remediation ID ELECTROKINETIC REMEDIATION; ELECTRIC-FIELDS; HEAVY-METALS; REMOVAL; ELECTROOSMOSIS; CONTAMINANTS; KAOLINITE AB Real-time spatially-resolved radiotracer and soil conductivity measurements were used to assess the fate of contaminants and the interaction of electrolysis products with Grout Vault Soil from the Department of Energy's Hanford site in Richland, Washington. Radiotracer techniques allowed the extent that a radioactive species was remediated to be unambiguously determined in the laboratory, and the method also provided insight into the immobilization of Cs+ by adsorption to the soil. Conductivity measurements provided a window into the changing state of the porous medium and the propagation of electrochemically-generated species that were introduced by water electrolysis at each active electrode. Measurements of the velocity of conductivity fronts generated by water electrolysis were combined with detailed geochemical and geophysical data about the soil to evaluate plausible soil chemistries in the system. Based on ion transport rates, it was shown that the alkaline nature of the soil buffered protons generated at the anode and hydroxide anions generated at the cathode titrated surface groups in the soil. (C) 1997 Elsevier Science B.V. C1 PACIFIC NW LAB, CHEM PROC DEV SECT, RICHLAND, WA 99352 USA. RP Schwartz, DT (reprint author), UNIV WASHINGTON, DEPT CHEM ENGN, BOX 351750, SEATTLE, WA 98195 USA. NR 23 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3894 J9 J HAZARD MATER JI J. Hazard. Mater. PD AUG PY 1997 VL 55 IS 1-3 BP 23 EP 37 DI 10.1016/S0304-3894(97)00015-0 PG 15 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA YF958 UT WOS:A1997YF95800004 ER PT J AU Stovall, TK Crabtree, JA Felde, DK Farquharson, G Park, JE AF Stovall, TK Crabtree, JA Felde, DK Farquharson, G Park, JE TI Effects of partial inlet blockages on high-velocity flow through a thin rectangular duct: Experimental and analytical results SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article AB The Advanced Neutron Source (ANS) reactor was designed to provide a research tool with capabilities beyond those of any existing reactors. One portion of its its state-of-the-art design required high velocity fluid flow through narrow channels between the fuel plates in the core, Experience with previous reactors had shown that fuel plate damage could occur if debris became lodged at the entrance to these channels. Such debris disrupts the fluid flow to the plate surfaces and could prevent adequate cooling of the fuel. Preliminary ANS designs addressed this issue by providing an unheated entrance length for each fuel plate so that any flow disruption would have time to recover before reaching the heated portions of-the fuel plates further downstream. As part of the safety analysis, the adequacy of this unheated entrance length was assessed using both analytical models and experimental measurements. The Flow Blockage Test Facility (FBTF) was designed and built to conduct experiments in an environment closely matching the ANS channel geometry. The FBTF permitted careful measurements of both hear transfer and hydraulic parameters. In addition to these experimental efforts, a thin rectangular channel was modeled using the FLUENT computational fluid dynamics computer code. The numerical results were compared to the experimental data to benchmark the hydrodynamics of the model. After this comparison, the model was extended to include those elements of the safety analysis difficult to measure experimentally. These elements included the high wall heat flux pattern and variable fluid properties. RP Stovall, TK (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 1997 VL 119 IS 3 BP 440 EP 450 DI 10.1115/1.2824117 PG 11 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA XV697 UT WOS:A1997XV69700007 ER PT J AU Scribner, KT Smith, MH Chesser, RK AF Scribner, KT Smith, MH Chesser, RK TI Spatial and temporal variability of microgeographic genetic structure in white-tailed deer SO JOURNAL OF MAMMALOGY LA English DT Article DE Odocoileus virginianus; white-tailed deer; genetics; management boundaries; population ecology; spatial subdivision ID MOOSE ALCES-ALCES; MULE DEER; POPULATIONS; DIFFERENTIATION; HETEROGENEITY; VIRGINIANUS; ODOCOILEUS; DIVERSITY; FLOW AB Techniques are described that define contiguous genetic subpopulations of white-tailed deer (Odocoileus virginianus) based on the spatial dispersion of 4,749 individuals that possessed discrete character values (alleles or genotypes) during each of 6 years (1974-1979), white-tailed deer were not uniformly distributed in space, but exhibited considerable spatial genetic structuring. Significant non-random clusters of individuals were documented during each year based on specific alleles and genotypes at the Sdh locus. Considerable temporal variation was observed in the position and genetic composition of specific clusters, which reflected changes in allele frequency in small geographic areas, The position of clusters did not consistently correspond with traditional management boundaries based on major discontinuities in habitat (swamp versus upland) and hunt compartments that were defined by roads and streams. Spatio-temporal stability of observed genetic contiguous clusters was interpreted relative to method and intensity of harvest, movements, and breeding ecology. C1 UNIV GEORGIA,DEPT ZOOL,ATHENS,GA 30602. SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. UNIV GEORGIA,SCH FOREST RESOURCES,INST ECOL,DEPT GENET,ATHENS,GA 30602. NR 41 TC 15 Z9 16 U1 2 U2 11 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD AUG PY 1997 VL 78 IS 3 BP 744 EP 755 DI 10.2307/1382933 PG 12 WC Zoology SC Zoology GA XU243 UT WOS:A1997XU24300004 ER PT J AU Goheen, SC Wahl, KL Campbell, JA Hess, WP AF Goheen, SC Wahl, KL Campbell, JA Hess, WP TI Mass spectrometry of low molecular mass solids by matrix-assisted laser desorption/ionization SO JOURNAL OF MASS SPECTROMETRY LA English DT Article DE matrix-assisted laser desorption/ionization; low molecular mass solids; organic acids; oxyanion salts; amine-based chelating compounds ID QUADRUPOLE ION-TRAP; DESORPTION IONIZATION; QUANTITATIVE-ANALYSIS; WEIGHT COMPOUNDS; GAS-PHASE; MALDI; PROTEINS; PEPTIDES; BIOPOLYMERS AB Matrix-assisted laser desorption/ionization combined with time-of-flight mass spectrometry (MALDI/TOF-MS) was used for the analysis of low molecular mass compounds. Three classes of molecules were studied: organic acids, salts of oxyanions and amine-based chelating compounds. Mass spectra from samples of citric, propionic, butyric, oxalic and stearic acid; ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), ethylenediamine N,N'-diacetic acid (EDDA) and nitrilotriacetic acid (NTA); and sulfate, nitrate, nitrite and phosphate salts were obtained. These species were analyzed alone and as mixtures in both the positive and negative ion modes. The organic acids and oxyanion salts displayed much stronger signals in the negative ion detection mode whereas chelating compounds, which contain basic amine functional groups, yielded stronger signals in the positive ion mode. This implies that detection sensitivity is often better for a particular ion mode in the analysis of small molecules containing limited classes of functional groups. In all analyses, the presence of high concentrations of sodium was found to quench the MALDI signals. To increase the detection sensitivity, some samples were processed through an ion-exchange column to remove sodium ions, This step was found to enhance the signal by two orders of magnitude over untreated samples. (C) 1997 by John Wiley & Sons, Ltd. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 50 TC 35 Z9 35 U1 0 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1076-5174 J9 J MASS SPECTROM JI J. Mass Spectrom. PD AUG PY 1997 VL 32 IS 8 BP 820 EP 828 DI 10.1002/(SICI)1096-9888(199708)32:8<820::AID-JMS538>3.3.CO;2-H PG 9 WC Biophysics; Chemistry, Organic; Spectroscopy SC Biophysics; Chemistry; Spectroscopy GA XQ564 UT WOS:A1997XQ56400004 ER PT J AU Steffani, CP Dini, JW Groza, JR Palazoglu, A AF Steffani, CP Dini, JW Groza, JR Palazoglu, A TI Electrodeposition and corrosion resistance of Ni-W-B coatings SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE acid resistance; chromium replacement; plating; surface finish AB A ternary nickel-base alloy Ni-W-B has been developed for surface corrosion and wear resistance to replace chromium plating, which uses environmentally hazardous solutions. The deposition conditions used an alkaline bath and insoluble anodes. The as-deposited alloy typically contains 40 wt% W and 1 wt% B and has an amorphous or partially amorphous structure. These deposits compare favorably with hexavalent chromium deposits in throwing power, color uniformity, and reflectivity. The corrosion resistance of Ni-W-B alloy was compared with hexavalent chromium and electroless nickel deposits in a variety of acids, including hydrochloric, sulfuric, fluoroboric, and phosphoric. In all cases, best results were obtained with the Ni-W-B deposits. C1 UNIV CALIF DAVIS,DEPT CHEM ENGN & MAT SCI,DAVIS,CA 95616. RP Steffani, CP (reprint author), LAWRENCE LIVERMORE NATL LAB,MFG & MAT ENGN DIV,LIVERMORE,CA 94550, USA. NR 5 TC 8 Z9 11 U1 1 U2 7 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD AUG PY 1997 VL 6 IS 4 BP 413 EP 416 DI 10.1007/s11665-997-0109-x PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA XN371 UT WOS:A1997XN37100003 ER PT J AU Lu, YC Kung, H Griffin, AJ Nastasi, MA Mitchell, TE AF Lu, YC Kung, H Griffin, AJ Nastasi, MA Mitchell, TE TI Observations of dislocations in Cu/Nb nanolayer composites after deformation SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MECHANICAL-PROPERTIES; THIN-FILMS; NB ALLOYS; MULTILAYERS; BEHAVIOR AB Dislocations have been observed in deformed Cu/Nb nanolayer composites of wavelength 17 and 7 nm. The dislocations thread through the Cu/Nb interfaces even though there is a change of Burgers vector. Conventional and high resolution transmission electron microscopy studies show that the in-plane bowing direction of these dislocations in the Cu layers is opposite to that in the Nb layers, so that the dislocations appear to zig-zag. These observations are explained by the presence of residual tensile stresses in Cu and residual compressive stresses in Nb, which make dislocations bow in opposite directions in the alternating layers. RP Lu, YC (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,DIV MAT SCI,LOS ALAMOS,NM 87545, USA. NR 17 TC 19 Z9 20 U1 2 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD AUG PY 1997 VL 12 IS 8 BP 1939 EP 1941 DI 10.1557/JMR.1997.0264 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA XQ278 UT WOS:A1997XQ27800002 ER PT J AU Weber, WJ Ewing, RC Angell, CA Arnold, GW Cormack, AN Delaye, JM Griscom, DL Hobbs, LW Navrotsky, A Price, DL Stoneham, AM Weinberg, WC AF Weber, WJ Ewing, RC Angell, CA Arnold, GW Cormack, AN Delaye, JM Griscom, DL Hobbs, LW Navrotsky, A Price, DL Stoneham, AM Weinberg, WC TI Radiation effects in glasses used for immobilization of high-level waste and plutonium disposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Review ID IRRADIATION-INDUCED DEFECTS; ELECTRON-SPIN RESONANCE; TRAPPED-HOLE-CENTERS; NUCLEAR WASTE; FUSED-SILICA; RADIOACTIVE-WASTE; HIGH-PURITY; MOLECULAR-DYNAMICS; VITREOUS SILICA; OXYGEN VACANCY AB This paper is a comprehensive review of the state-of-knowledge in the field of radiation effects in glasses that are to be used for the immobilization of high-level nuclear waste and plutonium disposition. The current status and issues in the area of radiation damage processes, defect generation, microstructure development, theoretical methods and experimental methods ase reviewed. Questions of fundamental and technological interest that offer opportunities for research are identified. C1 UNIV NEW MEXICO, DEPT EARTH & PLANETARY SCI, ALBUQUERQUE, NM 87131 USA. ARIZONA STATE UNIV, DEPT CHEM, TEMPE, AZ 85287 USA. CONSULTANTS INT, TIJERAS, NM 87059 USA. ALFRED UNIV, NEW YORK STATE COLL CERAM, ALFRED, NY 14802 USA. CTR ETUD SACLAY, DTA, SRMP, F-91191 GIF SUR YVETTE, FRANCE. USN, RES LAB, WASHINGTON, DC 20375 USA. MIT, DEPT MAT SCI & ENGN, CAMBRIDGE, MA 02139 USA. PRINCETON UNIV, PRINCETON MAT INST, PRINCETON, NJ 08544 USA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. UNIV LONDON UNIV COLL, DEPT PHYS & ASTRON, LONDON WC1E 6BT, ENGLAND. UNIV ARIZONA, DEPT MAT SCI & ENGN, TUCSON, AZ 85721 USA. RP Weber, WJ (reprint author), PACIFIC NW LAB, POB 999, MS K2-44, RICHLAND, WA 99352 USA. RI Weber, William/A-4177-2008; Price, David Long/A-8468-2013 OI Weber, William/0000-0002-9017-7365; NR 230 TC 247 Z9 256 U1 14 U2 63 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD AUG PY 1997 VL 12 IS 8 BP 1946 EP 1978 DI 10.1557/JMR.1997.0266 PG 33 WC Materials Science, Multidisciplinary SC Materials Science GA XQ278 UT WOS:A1997XQ27800004 ER PT J AU Shield, JE Kramer, MJ AF Shield, JE Kramer, MJ TI Deformation characteristics of quasicrystalline Al-Cu-Fe alloys SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID PLASTIC-DEFORMATION; QUASI-CRYSTALS AB The deformation characteristics of icosahedral Al-Cu-Fe quasicrystals were determined by high temperature creep experiments between 680 and 720 degrees C and 15 and 41 MPa. The deformation process was determined to be controlled by grain boundary mechanisms. Both the stress and grain size sensitivity exponents were found to be 2, suggesting that grain boundary sliding was the rate-controlling deformation mechanism. Microstructural analysis supported this conclusion, as no intragranular defects were produced during the deformation experiments. C1 US DOE,AMES LAB,AMES,IA 50011. RP Shield, JE (reprint author), UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112, USA. NR 12 TC 11 Z9 11 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD AUG PY 1997 VL 12 IS 8 BP 2043 EP 2047 DI 10.1557/JMR.1997.0274 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA XQ278 UT WOS:A1997XQ27800012 ER PT J AU Jisrawi, NM Wiesmann, H Ruckman, MW Thurston, TR Reisfeld, G Ocko, BM Strongin, M AF Jisrawi, NM Wiesmann, H Ruckman, MW Thurston, TR Reisfeld, G Ocko, BM Strongin, M TI In situ x-ray investigation of hydrogen charging in thin film bimetallic electrodes SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID DIFFRACTION; PALLADIUM; MONOLAYERS; DEUTERIUM; NIOBIUM; SYSTEM; ACID AB Hydrogen uptake and discharge by thin metallic films under potentiostatic control was studied using x-ray diffraction at the National Synchroton Light Source (NSLS), The formation of metal-hydrogen phases in Pd, Pd-capped Nb, and Pd/Nb multilayer electrode structures was deduced from x-ray diffraction data and correlated with the cyclic voltammetry (CV) peaks. The x-ray data were also used to construct a plot of the hydrogen concentration as a function of cell potential for a multilayered thin film. RP Jisrawi, NM (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 40 TC 3 Z9 3 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD AUG PY 1997 VL 12 IS 8 BP 2091 EP 2098 DI 10.1557/JMR.1997.0280 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA XQ278 UT WOS:A1997XQ27800018 ER PT J AU Vollath, D Szabo, DV Taylor, RD Willis, JO AF Vollath, D Szabo, DV Taylor, RD Willis, JO TI Synthesis and magnetic properties of nanostructured maghemite SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CERAMIC OXIDE POWDERS; FINE PARTICLE SYSTEM; SUSCEPTIBILITY PHENOMENA; MOSSBAUER; SPECTROSCOPY; DEPENDENCE; SPECTRA; FIELD; PEAK AB Nanocrystalline maghemite, gamma-Fe2O3, can be synthesized in a microwave plasma using FeCl3 or Fe-3(CO)(12) as the precursor. Electron microscopy revealed partide sizes in the range of 5 to 10 nm. In general, this material is superparamagnetic. The magnetic properties are strongly dependent on the precursor. In both cases the production process leads to a highly disordered material with the consequence of a low magnetization. The assumption of a disordered structure is also supported by electron energy loss (EEL) and Mossbauer spectroscopy. The structure of this material shows a nearly identical number of cations on tetrahedral and octahedral lattice sites. C1 LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP Vollath, D (reprint author), FORSCHUNGSZENTRUM KARLSRUHE,INST MAT FORSCH 3,POB 3640,D-76021 KARLSRUHE,GERMANY. RI Szabo, Dorothee Vinga/D-7569-2013 OI Szabo, Dorothee Vinga/0000-0002-5139-8771 NR 27 TC 119 Z9 121 U1 3 U2 31 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD AUG PY 1997 VL 12 IS 8 BP 2175 EP 2182 DI 10.1557/JMR.1997.0291 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA XQ278 UT WOS:A1997XQ27800029 ER PT J AU Sugama, T AF Sugama, T TI Oxidized potato-starch films as primer coatings of aluminium SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID GRAFT-COPOLYMERIZATION AB Potato-starch (PS) films for use as primer coatings of aluminium substrates were prepared in two steps, chemical-thermal-catalysed oxidation routes. The PS was modified with cerium (IV) ammonium nitrate (CAN) as a chemical oxidizer, followed by thermal oxidation at 150 degrees C in the presence of atmospheric oxygen; this led to the formation of a functional carbonyl derivative caused by cleavage of the glycol C-C bonds in glycosidic rings, thereby resulting in the ring openings. Increasing oxidation by raising the temperature to 200 and 250 degrees C promoted the conversion of carbonyl into carboxylate derivatives, while facilitating the breakage of C-O-C linkages in the open rings. The latter phenomenon reflected the formation of another carboxylate. The intermediate carboxylate derivatives favourably reacted with Ce4+ ions released from CAN to form cerium-bridged carboxylate complexes. Cerium-complexed carboxylate films used as primer coatings not only afforded some protection of aluminium substrates against corrosion, but also displayed excellent adhesion to both the polyurethane (PU) top-coating and aluminium sites. The latter demonstrated that the loss of adhesion at PU/primer/aluminium joints occurs in the PU layers, representing the mode of cohesive failure. RP Sugama, T (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,ENERGY EFFICIENCY & CONSERVAT DIV,UPTON,NY 11973, USA. NR 11 TC 9 Z9 11 U1 0 U2 7 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD AUG 1 PY 1997 VL 32 IS 15 BP 3995 EP 4003 DI 10.1023/A:1018681203069 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA XP279 UT WOS:A1997XP27900013 ER PT J AU Frost, BG Jenkins, TL AF Frost, BG Jenkins, TL TI On the interpretation of magnetic and electric fields imaged by low-magnification off-axis electron holography SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE electron holography; reference wave; electric fields; magnetic fields; Fresnel fringes; dislocations ID MICROSCOPY; WAVE AB The interpretation of magnetic and electric fields imaged by off-axis electron holography is not always straightforward. We will demonstrate this by some examples of possible misinterpretations which can result from, for example, comparing a hologram with a second one acquired such that the reference wave travelled on the opposite side of the sample, the diffraction of the electron beam at the biprism fibre, not centring an area to the true centre of the sideband when reconstructing the image wave by Fourier optics, quantification of 'magnetic' and 'electric' phases, procedures to separate electric from magnetic phases and dislocations in the interference fringes of the hologram. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Frost, BG (reprint author), UNIV TENNESSEE,EM FACIL,KNOXVILLE,TN 37996, USA. NR 23 TC 11 Z9 11 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD AUG PY 1997 VL 187 BP 85 EP 95 DI 10.1046/j.1365-2818.1997.1840748.x PN 2 PG 11 WC Microscopy SC Microscopy GA XX619 UT WOS:A1997XX61900002 ER PT J AU Mecklenburg, SL Donohoe, RJ Olah, GA AF Mecklenburg, SL Donohoe, RJ Olah, GA TI Tertiary structural changes and iron release from human serum transferrin SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE transferrin; X-ray scattering; iron release ID SMALL-ANGLE SCATTERING; X-RAY-SCATTERING; CONFORMATIONAL CHANGE; ION-BINDING; N-LOBE; KINETICS; RECEPTOR; LIGAND; SITE; PH AB Iron release from human serum transferrin was investigated by comparison of the extent of bound iron, measured by charge transfer absorption band intensity (465 nm), with changes observed by small-angle solution X-ray scattering (SAXS) for a series of equilibrated samples between pH 5.69 and 7.77. The phosphate buffers used in this study promote iron release at relatively high pH values, with an empirical pK of 6.9 for the convolved release from the two sites. The spectral data reveal that the N-lobe release is nearly complete by pH 7.0, while the C-lobe remains primarily metal-laden. Conversely, the radius of gyration, R-g, determined from the SAXS data remains constant between pH 7.77 and 7.05, and the evolution of R-g between its value observed for the diferric protein at PH 7.77 (31.2 +/- 0.2 Angstrom) and that of the apo protein at pH 5.69 (33.9 +/- 0.4 Angstrom) exhibits an empirical pK of 6.6. While R-g is effectively constant in the pH range associated with iron release from the N-lobe, the radius of gyration of cross-section, R-c, increases from 16.9 +/- .0.2 Angstrom to 17.6 +/- 0.2 A. Model simulations suggest that two different rotations of the NII domain relative to the NT domain about a hinge deep in the iron-binding cleft of the N-lobe, one parallel with and one perpendicular to the plane of the iron-binding site, can be significantly advanced relative to their hole protein positions while yielding constant R-g and increased R-c values consistent with the scattering data. Rotation of the CII domain parallel with the C-lobe iron-binding site plane can partially account for the increased R-g values measured at low pH; however, no reasonable combined repositioning of the NII and CII domains yields the experimentally observed increase in R-g. C1 LOS ALAMOS NATL LAB,BIOCHEM & BIOTECHNOL GRP,LOS ALAMOS,NM 87545. RI Mecklenburg, Sandra/F-4571-2010 NR 51 TC 29 Z9 29 U1 1 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD AUG 1 PY 1997 VL 270 IS 5 BP 739 EP 750 DI 10.1006/jmbi.1997.1126 PG 12 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XN949 UT WOS:A1997XN94900010 PM 9245601 ER PT J AU Marr, AJ Sears, TJ Davies, PB AF Marr, AJ Sears, TJ Davies, PB TI High-resolution infrared diode laser spectroscopy of CBr SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID SPECTRUM; TRANSITION; HCBR; ROTATION AB The infrared spectrum of the X (II)-I-2 state of CBr from 680 to 760 cm(-1) has been measured using diode laser absorption spectroscopy. This is the first observation of a vibrational spectrum of the radical in the gas phase. The radicals were produced by 193 nm excimer laser photolysis of bromoform. Transitions belonging to the nu = 1 <-- 0, 2 <-- 1, 3 <-- 2, and 4 <-- 3 bands of both isotopomers, (CBr)-Br-79 and (CBr)-Br-81, have been identified. Spectroscopic parameters were obtained from a least-squares fit to an effective Hamiltonian where the transition frequencies of both isotopomers were fitted simultaneously. The results were used to obtain a Rydberg-Klein-Rees potential. (C) 1997 Academic Press. C1 UNIV CAMBRIDGE,DEPT CHEM,CAMBRIDGE CB2 1EW,ENGLAND. RP Marr, AJ (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Sears, Trevor/B-5990-2013 OI Sears, Trevor/0000-0002-5559-0154 NR 22 TC 21 Z9 23 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD AUG PY 1997 VL 184 IS 2 BP 413 EP 433 DI 10.1006/jmsp.1997.7349 PG 21 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XY001 UT WOS:A1997XY00100020 ER PT J AU Vanheusden, K Warren, WL Devine, RAB AF Vanheusden, K Warren, WL Devine, RAB TI H+ and D+ associated charge buildup during annealing of Si/SiO2/Si structures SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT Franco-Italian Symposium on Structure and Defects in SiO(2), Fundamentals and Applications CY SEP 23-25, 1996 CL AGELONDE, FRANCE ID INTERFACE TRAP FORMATION; TIME-DEPENDENCE AB Si/SiO2/Si structures produced by high temperature processing have been annealed in atmospheres containing forming gas (5% H-2, 95% N-2 or 5% D-2, 95% N-2) at temperatures in the range 200-900 degrees C. For temperatures greater than or equal to 500 degrees C spontaneous positive electrical charging in the SiO2 layer is observed. Electron and hole injection experiments confirm that the charging is not due to holes but must be attributed to protons or deuterons. Both static and mobile species are formed dependent upon the confined (Si/SiO2/Si) or unconfined (SiO2/Si) nature of the structure of the sample. Application of an electric field similar to 10(5) V cm(-1) results in motion of the mobile ions with an activation energy estimated to be 0.81 +/- 0.02 eV both for deuterons and protons. A root mass factor is evidenced resulting in the conclusion that the protons are more mobile than the deuterons. The physical origin of the charging phenomenon is attributed to the formation of over coordinated oxygen atoms with the H or D attaching themselves to oxygens in strained Si-O-Si bonds near the Si/SiO2 interface, the positive charged state is stabilised by loss of an electron to the Si conduction band. It is assumed that strongly bound over coordinated oxygens near the interface constitute the fixed oxide charge species while more weakly bound forms migrating from Si-O-Si unit to Si-O-Si unit are the origin of the mobile species. (C) 1997 Elsevier Science B.V. C1 FRANCE TELECOM,CTR NATL ETUD TELECOMMUN,F-38243 MEYLAN,FRANCE. SANDIA NATL LABS,ADV MAT LAB,ALBUQUERQUE,NM 87185. NR 8 TC 16 Z9 16 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD AUG 1 PY 1997 VL 216 BP 116 EP 123 DI 10.1016/S0022-3093(97)00178-6 PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA XU618 UT WOS:A1997XU61800020 ER PT J AU Haire, RG AF Haire, RG TI The high-temperature vaporization/decomposition of actinide materials: fundamental and technological aspects SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 9th International Symposium on Thermodynamics of Nuclear Materials (STNM-9) / 14th IUPAC Conference on Chemical Thermodynamics CY AUG 25-30, 1996 CL TOYONAKA, JAPAN SP Atomic Energy Soc Japan ID THERMODYNAMIC FUNCTIONS; VAPORIZATION AB The unique and variable chemistry exhibited across the actinide series offers a scientifically challenging group of elements. Investigations of their high-temperature materials science and thermodynamics can provide important insights into fundamental actinide science and generate critical information for technological applications. The wide variations in the physicochemical properties and the availability of the various actinide elements necessitates special experimental techniques be employed, even when investigating a single property (e.g., the enthalpy of vaporization). Experimental approaches range can from classical to novel methods to permit studies of the rarer and the more intensely radioactive members. We have developed special equipment and techniques to investigate the high-temperature, physicochemical properties of several actinides through Md, as well as the precursor elements, radium and actinium. These experimental approaches employed both alloys and solid solutions of compounds, in addition to the pure elements themselves. The vaporization/decomposition of compounds and the sublimation of the elements, together with the associated thermodynamics, are the main issues. Results for several of the actinide elements, some of the techniques employed and systematic comparisons of the thermochemical aspects of bonding are discussed to give a fuller understanding of the series as a whole. (C) 1997 Elsevier Science B.V. RP Haire, RG (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,POB 2008,MS-6375,OAK RIDGE,TN 37831, USA. NR 21 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD AUG PY 1997 VL 247 BP 1 EP 6 DI 10.1016/S0022-3115(97)00024-X PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XU687 UT WOS:A1997XU68700002 ER PT J AU Krikorian, OH Fontes, AS Ebbinghaus, BB Adamson, MG AF Krikorian, OH Fontes, AS Ebbinghaus, BB Adamson, MG TI Transpiration studies on the volatilities of PuO3(g) and PuO2(OH)(2)(g) from PuO2(s) in the presence of steam and oxygen and application to plutonium volatility in mixed-waste thermal oxidation processors SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 9th International Symposium on Thermodynamics of Nuclear Materials (STNM-9) / 14th IUPAC Conference on Chemical Thermodynamics CY AUG 25-30, 1996 CL TOYONAKA, JAPAN SP Atomic Energy Soc Japan AB Transpiration experiments have been carried out to study the volatility of PuO2(s) in the presence of oxygen and steam. Vapor pressures have been measured for PuO3(g) and PuO2(OH)(2)(g) and thermodynamic data established for them. Thus, Delta(f)H(298)(0) is determined to be -(562.8 +/- 5.0) kJ/mol for PuO3(g) and -(1,018.2 +/- 3.3) kJ/mol for PuO2(OH)(2)(g). In applying the Pu volatility data to a pilot scale mixed waste (containing both radioactive and hazardous constituents) incinerator with primary and secondary combustion chambers, it is found that Pu volatilization makes a negligible contribution to air emissions if the temperature in the secondary combustor is maintained at less than 1600 K. Chlorine-and fluorine-induced volatilities of plutonium are not considered in this analysis. (C) 1997 Elsevier Science B.V. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. NR 9 TC 8 Z9 8 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD AUG PY 1997 VL 247 BP 161 EP 171 DI 10.1016/S0022-3115(97)00043-3 PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XU687 UT WOS:A1997XU68700032 ER PT J AU Johnson, I Johnson, CE AF Johnson, I Johnson, CE TI Light element thermodynamics related to actinide separations SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 9th International Symposium on Thermodynamics of Nuclear Materials (STNM-9) / 14th IUPAC Conference on Chemical Thermodynamics CY AUG 25-30, 1996 CL TOYONAKA, JAPAN SP Atomic Energy Soc Japan AB The accumulation of waste from the last five decades of nuclear reactor development has resulted in large quantities of materials of very diverse chemical composition. An electrometallurgical (EM) method is being developed to separate the components of the waste into several unique streams suitable for permanent disposal and an actinide stream suitable for retrievable storage. The principal types of nuclear wastes are spent oxide or metallic fuel. Since the EM module requires a metallic feed, and oxygen interferes with its operation, the oxide fuel has to be reduced prior to EM treatment. Further, the wastes contain, in addition to oxygen, other light elements (first-and second-row elements) that may also interfere with the operation of the EM module. The extent that these light elements interfere with the operation of the EM module has been determined by chemical thermodynamic calculations. (C) 1997 Elsevier Science B.V. RP Johnson, I (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD AUG PY 1997 VL 247 BP 177 EP 182 DI 10.1016/S0022-3115(97)00045-7 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XU687 UT WOS:A1997XU68700034 ER PT J AU Ogawa, T Akabori, M Kobayashi, F Haire, RG AF Ogawa, T Akabori, M Kobayashi, F Haire, RG TI Thermochemical modeling of actinide alloys related to advanced fuel cycles SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 9th International Symposium on Thermodynamics of Nuclear Materials (STNM-9) / 14th IUPAC Conference on Chemical Thermodynamics CY AUG 25-30, 1996 CL TOYONAKA, JAPAN SP Atomic Energy Soc Japan ID U-ZR ALLOYS; THERMODYNAMIC PROPERTIES; ZIRCONIUM SYSTEM; PHASE-RELATIONS; NEPTUNIUM; BEHAVIOR; NP; TEMPERATURES; EQUILIBRIA; STABILITY AB Innovative approaches for improved management of transuranium elements are being sought. The use of either metallic or nitride fuels, coupled with pyrochemical reprocessing techniques, are being studied. As our experience with these advanced fuels is limited, their development will be promoted by thermochemical analysis. This paper reviews our thermochemical modeling of technical problems related to advanced fuel cycles and presents models of the actinide alloys and nitrides together with experimental verification of these thermochemical predictions. (C) 1997 Elsevier Science B.V. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Ogawa, T (reprint author), JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. NR 38 TC 10 Z9 10 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD AUG PY 1997 VL 247 BP 215 EP 221 DI 10.1016/S0022-3115(97)00047-0 PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XU687 UT WOS:A1997XU68700040 ER PT J AU Akabori, M Haire, RG Gibson, JK Okamoto, Y Ogawa, T AF Akabori, M Haire, RG Gibson, JK Okamoto, Y Ogawa, T TI An X-ray diffraction study of the Np-Ni system SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 9th International Symposium on Thermodynamics of Nuclear Materials (STNM-9) / 14th IUPAC Conference on Chemical Thermodynamics CY AUG 25-30, 1996 CL TOYONAKA, JAPAN SP Atomic Energy Soc Japan ID NEPTUNIUM; METALS AB The neptunium-nickel binary system has been studied by means of powder X-ray diffraction. The previously reported NpNi2 Laves phase was confirmed and a previously unknown intermetallic compound, Np2Ni17, was identified. The crystal symmetry of Np2Ni17 was determined to be the Th2Ni17 type hexagonal structure which is the same as that of Pu2Ni17. The lattice parameters of Np2Ni17 were calculated to be a(0) = 0.8333 +/- 0.0005 and c(0) = 0.8010 +/- 0.0009 nm. The solubility limit of nickel in Np-Ni solid solutions and the composition range of NpNi2 compound were also discussed. (C) 1997 Elsevier Science B.V. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,TRANSURANIUM RES LAB,OAK RIDGE,TN 37830. RP Akabori, M (reprint author), JAPAN ATOM ENERGY RES INST,DEPT CHEM & FUELS RES,TOKAI,IBARAKI 31911,JAPAN. NR 18 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD AUG PY 1997 VL 247 BP 240 EP 243 DI 10.1016/S0022-3115(97)00073-1 PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XU687 UT WOS:A1997XU68700045 ER PT J AU Sutherland, BM AF Sutherland, BM TI UV effects in ''the real world'': Problems of UV dosimetry in complex organisms SO JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY LA English DT Article; Proceedings Paper CT 2nd International Workshop of Biological UV Dosimetry CY AUG 28-30, 1996 CL BUDAPEST, HUNGARY DE complex organisms; UV dosimetry; UV effects ID PYRIMIDINE DIMERS; STRAND BREAKS; DNA; QUANTITATION; WAVELENGTHS AB Understanding the effects of UV radiation on higher plants and animals is essential for evaluating the consequences of environmental changes which could alter the UV levels in the biosphere. Although analytical approaches for quantifying UV exposures and resulting cellular damage levels in optically simple systems (DNA in dilute solution, viruses or microorganisms in dilute suspension and monolayers of cultured cells) are well known, these methods may not be applicable to optically complex systems, such as multilayered plants and animals, or microorganisms in absorbing milieu such as natural lakes or oceans. Understanding the problems, pitfalls and solutions to the quantification of UV exposures and cellular damage is critical for evaluating the effects of environmental UV on complex organisms. (C) 1997 Elsevier Science S.A. RP Sutherland, BM (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. NR 9 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1011-1344 J9 J PHOTOCH PHOTOBIO B JI J. Photochem. Photobiol. B-Biol. PD AUG PY 1997 VL 40 IS 1 BP 8 EP 13 DI 10.1016/S1011-1344(97)82942-9 PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA XW699 UT WOS:A1997XW69900003 PM 9301040 ER PT J AU Sutherland, JC Monteleone, DC Sutherland, BM AF Sutherland, JC Monteleone, DC Sutherland, BM TI Computer network for data acquisition, storage and analysis SO JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY LA English DT Article; Proceedings Paper CT 2nd International Workshop of Biological UV Dosimetry CY AUG 28-30, 1996 CL BUDAPEST, HUNGARY DE computers; data acquisition instruments; data analysis; data storage; networks ID FLUORESCENCE; DNA AB Modern scientific instruments can produce huge quantities of data, usually in digital form. However, data acquisition is only one of three important functions. To be useful, data must also be stored and analyzed. Fortunately, the same computer-based technologies that facilitate the generation of large data-sets provide tools to accomplish these tasks. We describe a data system based on computers connected to a network developed for this purpose. (C) 1997 Elsevier Science S.A. RP Sutherland, JC (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. FU NCRR NIH HHS [RR07338]; NHGRI NIH HHS [HG00371] NR 9 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1011-1344 J9 J PHOTOCH PHOTOBIO B JI J. Photochem. Photobiol. B-Biol. PD AUG PY 1997 VL 40 IS 1 BP 14 EP 22 DI 10.1016/S1011-1344(97)00030-4 PG 9 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA XW699 UT WOS:A1997XW69900004 PM 9301041 ER PT J AU Arunasalam, V AF Arunasalam, V TI Ion cyclotron emission due to fast Alfven-wave radiative instabilities in tokamaks induced by newly born fusion products SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID TEST REACTOR; PLASMAS; DEUTERIUM; TRITIUM; TFTR; EXCITATION; TRANSPORT; JET AB The velocity distribution functions of newly born (t = 0) charged fusion products (protons in DD and alpha particles in DT plasmas) of tokamak discharges can be approximated by a monoenergetic ring distribution with a finite upsilon(parallel to) such that upsilon(perpendicular to) approximate to upsilon(parallel to) approximate to V-j, where 1/2M(j)V(j)(2) = E-j, the directed birth energy of the charged fusion-product species j of mass M-j. As the time t progresses, these distribution functions will evolve into a Gaussian in velocity (i.e. a drifting Maxwellian type), with thermal spreads given by the perpendicular and parallel temperatures T-perpendicular to j(t) = T-parallel to j(t), with T-j(t) increasing as t increases and finally reaching an isotropic saturation value of T-perpendicular to j(t approximate to tau(j)) = T-parallel to j(t approximate to tau(j)) = T-j(t approximate to tau(j)) approximate to [MjTdEj/(M-j + M)](1/2). Here T-d is the temperature of the background deuterium plasma ions, M is the mass of a triton or a neutron for j = protons and alpha particles respectively, and tau(j) approximate to 1/4 tau(sj) the thermalization time of the fusion product species j in the background deuterium plasma, with tau(sj) the slowing-down time. For times t of the order of tau(j), the distributions can be approximated by a Gaussian in the total energy (i.e. a Brysk type). Then, for times t greater than or equal to tau(sj), the velocity distributions of the fusion products will relax towards their appropriate slowing-down distributions. Here we shall examine the radiative stability of all these (i.e. a monoenergetic ring, a Gaussian in velocity, a Gaussian in energy, and the slowing-down) distributions. RP Arunasalam, V (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 48 TC 1 Z9 1 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD AUG-SEP PY 1997 VL 58 BP 287 EP 313 DI 10.1017/S0022377897005618 PN 2 PG 27 WC Physics, Fluids & Plasmas SC Physics GA YC646 UT WOS:A1997YC64600008 ER PT J AU Iglesias, CA AF Iglesias, CA TI Collective effects in bremsstrahlung in plasmas - Comment on SO JOURNAL OF PLASMA PHYSICS LA English DT Article AB In a recent study Tsytovich et al. [J. Plasma Phys. 56, 127 (1996)] claimed to obtain new expressions for electron-ion bremsstrahlung in plasmas. It is shown, however, that they interpreted earlier work incorrectly and simply reproduced well-known results. RP Iglesias, CA (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD AUG-SEP PY 1997 VL 58 BP 381 EP 383 DI 10.1017/S0022377897005825 PN 2 PG 3 WC Physics, Fluids & Plasmas SC Physics GA YC646 UT WOS:A1997YC64600013 ER PT J AU MedellinRodriguez, FJ Phillips, PJ Lin, JS Campos, R AF MedellinRodriguez, FJ Phillips, PJ Lin, JS Campos, R TI The triple melting behavior of poly(ethylene terephthalate): Molecular weight effects SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE polyesters; crystallization; melting; morphology ID ANGLE X-RAY; SEMI-CRYSTALLINE POLY(ETHYLENE-TEREPHTHALATE); 2-PHASE SYSTEMS; SCATTERING; MORPHOLOGY; PET; PERFECTION; POLYMERS; PEEK AB The melting behavior of isothermally crystallized PET has been studied using linear heating in a differential scanning calorimeter (DSC). Variables such as crystallization temperature, crystallization time, heating rate, and average molecular weight are the main focus of the study. On the basis of several experimental techniques, a correlation of the melting behavior of PET with the amount of secondary crystallization was found to exist. It was observed that the triple melting of PET is a function of programmable DSC variables such as crystallization temperature, crystallization time, and heating rate. However, in testing the hypothesis that there was a correlation between melting endotherms and secondary crystallization inside spherulites, it was found necessary to use a DSC-independent variable in order to enhance the observed effects. Therefore, on the basis of a crystallization model that involves secondary branching along the edges of parent lamellar structures, it was speculated that an increase in the average molecular weight could affect the triple melting of PET due to an increase of rejected portions of the macromolecules. It was found that the second melting endotherm increased, apparently, at the expense of the third one as the average molecular weight was increased. The second melting endotherm was also found to correlate proportionally with the amount of secondary crystallization inside spherulites. The results support a model of crystallization which basically consists of parent crystals and at least one population of secondary, probably metastable, crystals. This latter structural component must involve excluded portions of the macromolecules that did not crystallize during the isothermal crystallization period of the parent crystals. An increase of molecular weight gives rise to a higher entanglement density which in turn increases the fraction of initially rejected chain sections and therefore the amount of secondary crystallization. (C) 1997 John Wiley & Sons, Inc. C1 UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996. UNIV AUTONOMA SAN LUIS POTOSI,CTR INVEST & ESTUDIOS POSTGRAD FCQ,SAN LUIS POTOSI 78210,MEXICO. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV AUTONOMA SAN LUIS POTOSI,ESCUELA MET,FCQ,SAN LUIS POTOSI 78216,MEXICO. NR 43 TC 71 Z9 71 U1 1 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD AUG PY 1997 VL 35 IS 11 BP 1757 EP 1774 DI 10.1002/(SICI)1099-0488(199708)35:11<1757::AID-POLB9>3.0.CO;2-P PG 18 WC Polymer Science SC Polymer Science GA XM223 UT WOS:A1997XM22300009 ER PT J AU Smith, JA Rolfe, ST AF Smith, JA Rolfe, ST TI The significance of crack depth (a) and crack depth-to-width ratio (a/W) with respect to the behavior of very large specimens SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID TRIAXIALITY PARAMETER; FRACTURE; FAMILY; FIELDS AB Previous studies have shown that there is an increase in cleavage fracture toughness of laboratory specimens with shallow flaws compared with those laboratory specimens having deep flaws. Typical crack depths in real structures generally are very small relative to the member width. Therefore, the crack depth to structural member width (a/W) ratios are very small (less than 0.1). Accordingly, the effect of this observation on the behavior of larger structures that actually represent typical engineering applications could be significant. Using experimental and analytical results from previous studies on A533-B steel specimens, the effect of the shallow flaw behavior with respect to very large specimens was examined. Using the Dodds and Anderson constraint correction, predictions of the cleavage fracture toughness of large-scale wide-plate tests and full thickness clad beams from an actual reactor pressure vessel were shown to compare favorably with actual test results. The results of these studies suggest the possibility of predicting the increase in fracture roughness for low constraint structural geometries using high-constraint laboratory rest specimen results. The ability to take advantage of this increase in toughness in analysis of actual structures could be very useful in estimating the actual safety and reliability of existing structures with service cracks. C1 UNIV KANSAS, DEPT CIVIL ENGN, LAWRENCE, KS 66045 USA. RP Smith, JA (reprint author), SANDIA NATL LABS, POB 5800, MS 0340, ALBUQUERQUE, NM 87111 USA. NR 25 TC 1 Z9 1 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD AUG PY 1997 VL 119 IS 3 BP 279 EP 287 DI 10.1115/1.2842305 PG 9 WC Engineering, Mechanical SC Engineering GA XT813 UT WOS:A1997XT81300005 ER PT J AU Lee, YH Dai, S Young, JP AF Lee, YH Dai, S Young, JP TI Silver-doped sol-gel films as the substrate for surface-enhanced Raman scattering SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID COLLOIDAL SILVER; RESONANCE RAMAN; SPECTROSCOPY; GOLD; SPECTROMETRY; ELECTRODE; SPECTRUM; SERS; ION AB A method was developed to prepare silver-doped sol-gel films for surface-enhanced Raman scattering (SERS) detection. The technique involves first doping silver lions as a silver ammine complex [Ag(NH3)(2)(+)] into a sol-gel matrix, followed by chemical reduction of the doped silver ions into the corresponding silver metal particles, The silver-doped sol-gel films coated on a glass substrate exhibit strong enhancement (24000-fold) of Raman scattering from molecules adsorbed on the surface. Very stable SERS spectra of benzoic acid over a period of 48 h were obtained with the new silver substrate. (C) 1997 John Wiley & Sons Ltd. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RI Dai, Sheng/K-8411-2015 OI Dai, Sheng/0000-0002-8046-3931 NR 33 TC 37 Z9 37 U1 1 U2 6 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD AUG PY 1997 VL 28 IS 8 BP 635 EP 639 DI 10.1002/(SICI)1097-4555(199708)28:8<635::AID-JRS152>3.0.CO;2-0 PG 5 WC Spectroscopy SC Spectroscopy GA XY947 UT WOS:A1997XY94700012 ER PT J AU Markham, JR Cosgrove, JE Nelson, CM Bonanno, AS Schlief, RE Stoy, MA Glatzmaier, GC Bingham, CE Lewandowski, AA AF Markham, JR Cosgrove, JE Nelson, CM Bonanno, AS Schlief, RE Stoy, MA Glatzmaier, GC Bingham, CE Lewandowski, AA TI In-situ FT-IR monitoring of a solar flux induced chemical process SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB The capability to perform in-situ, on-line monitoring of processes induced by concentrated solar flux will enhance the development and utilization of solar technologies. Temperature measurements and chemical concentration measurements provide an understanding of the ongoing chemistry, process limits, and process reproducibility, A Fourier transform infrared (FT-IR) spectrometer was optically coupled to a quartz pow reactor at the High Flux Solar Furnace of the National Renewable Energy Laboratory in Golden, CO. In-situ emission/transmission spectroscopy was utilized to simultaneously,monitor steam temperature and the concentration of formed hydrogen bromide during the solar flux induced reaction of steam and bromine. The photochemical process is being investigated for the production of industrial quantities of hydrogen and oxy,gen, where downstream electrolysis of the formed hydrogen bromide provides the hydrogen and regenerates bromine. Steam temperature was measured to increase upon the addition of bromine to the reactor. Gas temperature increases of 200 degrees C to 400 degrees C were observed. Hydrogen bromide concentrations rip to ten percent of the reactor gas volume were measured. The FT-IR system provided quantitative information of two critical parameters of;he measured process and serves to accelerate this technology area. C1 ONLINE TECHNOL INC,E HARTFORD,CT 06108. SOLAR REACTOR TECHNOL INC,MIAMI,FL 33233. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP Markham, JR (reprint author), ADV FUEL RES INC,87 CHURCH ST,E HARTFORD,CT 06108, USA. NR 8 TC 4 Z9 4 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD AUG PY 1997 VL 119 IS 3 BP 219 EP 224 DI 10.1115/1.2888022 PG 6 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA XT781 UT WOS:A1997XT78100005 ER PT J AU Tangler, JL AF Tangler, JL TI Influence of pitch, twist, and taper on a blade's performance loss due to roughness SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade's sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due ta roughness effects fat several rotors. In addition to airfoil geometry; this evaluation suggested that a rotor's sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP93 computer code with wind tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative ta a constant-chord nontwisted blade at several blade pitch angles. The results indicate that a constant-chord nontwisted blade pitched toward stall will have the greatest losses Rile to roughness. The use of twist, taper, and positive blade-pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. RP Tangler, JL (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD AUG PY 1997 VL 119 IS 3 BP 248 EP 252 DI 10.1115/1.2888027 PG 5 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA XT781 UT WOS:A1997XT78100010 ER PT J AU Steele, IM Pluth, JJ Richardson, JW AF Steele, IM Pluth, JJ Richardson, JW TI Crystal structure of tribasic lead sulfate (3PbO center dot PbSO4 center dot H2O) by X-rays and neutrons: An intermediate phase in the production of lead acid batteries SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article AB The crystal structure of tribasic lead sulfate (3PbO . PbSO4 . H2O) has been determined by a combination of single crystal X-ray and powder neutron diffraction to R of 0.024. From X-ray data, the space group is P (1) over bar, a=6.378(1), b=7.454(2), c=10.308(2) Angstrom, alpha=75.26(3), beta=79.37(3), gamma=88.16(3)degrees. The structure can be represented with two types of layers: (i) hexagonal nets of Pb and (ii) similar layers but with 1/2 of Pb replaced by equal numbers of S and 2H. These layers are stacked in the sequence...BAABAA...Structural units can be identified in tetragonal and orthorhombic PbO which are also present in tribasic lead sulfate and provide a common basis for relating these structures. These units are defined by Pb-O bonds which are less than 2.5 Angstrom which represent the strongest linkages. Two OH groups form weak hydrogen bonds to a single oxygen of a sulfate group. Lead polyhedra show both a range in coordination and Pb-O distances consistent with oxygen forming irregular polyhedra within the more regular cation framework. An alternative formula, 4PbO . H2SO4, may better represent the structure with the suggestion that H-2 and SO4 groups replace Pb rather than the incorporation of H2O groups. (C) 1997 Academic Press. C1 UNIV CHICAGO,CONSORTIUM ADV RADIAT SOURCES,CHICAGO,IL 60637. UNIV CHICAGO,MAT RES SCI & ENGN CTR,CHICAGO,IL 60637. ARGONNE NATL LAB,ARGONNE,IL 60439. RP Steele, IM (reprint author), UNIV CHICAGO,DEPT GEOPHYS SCI,5734 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 8 TC 19 Z9 19 U1 1 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD AUG PY 1997 VL 132 IS 1 BP 173 EP 181 DI 10.1006/jssc.1997.7440 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA XY689 UT WOS:A1997XY68900023 ER PT J AU Aranda, MAG Bruque, S Attfield, JP Palacio, F VonDreele, RB AF Aranda, MAG Bruque, S Attfield, JP Palacio, F VonDreele, RB TI Changes in magnetic couplings after chimie douce reactions: Magnetic structures of LiMnXO4(OD) (X = P, As) SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID MANGANESE(III) ARSENATE HYDRATE; TOPOTACTIC LITHIUM EXCHANGE; POWDER DIFFRACTION DATA; PHOSPHATE; FRAMEWORK; PHASE AB The structural and magnetic changes that take place after the lithium exchange reactions of MnXO4 . D2O to give LiMnXO4(OD) (X=P, As) have been studied by magnetic susceptibility and variable-temperature neutron diffraction techniques. The crystal structures of the lithium derivatives have been refined at room temperature and 10 K by time-of-light neutron ponder diffraction data using the Rietveld method. These compounds behave as Curie-Weiss paramagnets at high temperatures and order antiferromagnetically below Neel temperatures of 28 and 30 K for X=P and As, respectively. The magnetic structures have been determined from the low-temperature neutron data. Although the four magnetic structures are antiferromagnetic, the magnetic couplings in the Mn-O-Mn infinite chains are ferromagnetic in the lithium derivatives and antiferromagnetic in the parent materials. These different magnetic behaviors are explained on the basis of subtle differences in the crystal structures after the lithium exchange reaction. (C) 1997 Academic Press. C1 UNIV CAMBRIDGE,DEPT CHEM,CAMBRIDGE CB2 1EW,ENGLAND. UNIV ZARAGOZA,CSIC,INST CIENCIAS MAT ARAGON,E-50009 ZARAGOZA,SPAIN. LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,MSH805,LOS ALAMOS,NM 87545. RP Aranda, MAG (reprint author), UNIV MALAGA,DEPT QUIM INORGAN,APTD 59,E-29071 MALAGA,SPAIN. RI Aranda, Miguel A.G./D-4614-2009; Bruque-Gamez, Sebastian/K-4351-2012; Palacio, Fernando/A-1270-2013 OI Aranda, Miguel A.G./0000-0001-7708-3578; Bruque-Gamez, Sebastian/0000-0003-3977-9595; Palacio, Fernando/0000-0002-6403-7270 NR 22 TC 16 Z9 18 U1 0 U2 6 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD AUG PY 1997 VL 132 IS 1 BP 202 EP 212 DI 10.1006/jssc.1997.7465 PG 11 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA XY689 UT WOS:A1997XY68900027 ER PT J AU Luo, LS AF Luo, LS TI Analytic solutions of linearized lattice Boltzmann equation for simple flows SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE Lattice Boltzmann equation; lattice-gas automata; linearized lattice Boltzmann equation; analytic solutions for the plane Couette and the Poiseuille flows; slip at wall ID GAS AUTOMATA; GENERALIZED HYDRODYNAMICS; TRANSPORT; FLUIDS AB A general procedure to obtain analytic solutions of the linearized lattice Boltzmann equation for simple flows is developed. As examples, the solutions for the Poiseuille and the plane Couette flows in two-dimensional space are obtained and studied in detail. The solutions not only have a component which is the solution of the Navier-Stokes equation, they also include a kinetic component which cannot be obtained by the Navier-Stokes equation. The kinetic component of the solutions is due to the finite-mean-free-path effect. Comparison between the analytic results and the numerical results of lattice-gas simulations is made, and they are found to be in accurate agreement. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP Luo, LS (reprint author), LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,DIV THEORET,MS-B213,LOS ALAMOS,NM 87545, USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 21 TC 31 Z9 32 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD AUG PY 1997 VL 88 IS 3-4 BP 913 EP 926 DI 10.1023/B:JOSS.0000015178.19008.78 PG 14 WC Physics, Mathematical SC Physics GA XV186 UT WOS:A1997XV18600016 ER PT J AU He, XY Luo, LS AF He, XY Luo, LS TI Lattice Boltzmann model for the incompressible Navier-Stokes equation SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE lattice Boltzmann method; incompressible Navier-Stokes equation; Poiseuille flow; Womersley flow AB In this paper a lattice Boltzmann (LB) model to simulate incompressible flow is developed. The main idea is to explicitly eliminate the terms of o(M-2), where M is the Mach number, due to the density fluctuation in the existing LB models. In the proposed incompressible LB model, the pressure p instead of the mass density p is the independent dynamic variable. The incompressible Navier-Stokes equations are derived from the incompressible LB model via Chapman-Enskog procedure. Numerical results of simulations of the plane Poiseuille now driven either by pressure gradient or a Fixed velocity profile at entrance as well as of the 2D Womersley flow are presented. The numerical results are found to be in excellent agreement with theory. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP He, XY (reprint author), UNIV CALIF LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,DIV THEORET,MS B213,LOS ALAMOS,NM 87545, USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 14 TC 514 Z9 538 U1 10 U2 65 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD AUG PY 1997 VL 88 IS 3-4 BP 927 EP 944 DI 10.1023/B:JOSS.0000015179.12689.e4 PG 18 WC Physics, Mathematical SC Physics GA XV186 UT WOS:A1997XV18600017 ER PT J AU Kresin, VZ Bill, A Wolf, SA Ovchinnikov, YN AF Kresin, VZ Bill, A Wolf, SA Ovchinnikov, YN TI Magnetic scattering in the cuprates: Upper limit of T-c, novel isotope effects SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE magnetic scattering; upper limit of T-c; isotope effect ID NORMAL-STATE; LAYERED SUPERCONDUCTORS; PAIR BREAKING; FIELD; TL2BA2CUO6+DELTA; TEMPERATURE; DEPENDENCE; YBA2CU3O7; OXIDES AB The pair-breaking effect caused by magnetic scattering makes a strong impact on the properties of cuprates. The study of magnetic properties allows one to introduce a new parameter, the intrinsic T-c, which is the upper limit of T-c in these materials: T-c,T-upp = 160-170 K. In addition, the presence of magnetic impurities leads to the unconventional isotope effect observed experimentally. C1 USN, RES LAB, WASHINGTON, DC 20375 USA. LD LANDAU THEORET PHYS INST, MOSCOW 11733V, RUSSIA. RP Kresin, VZ (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RI Wolf, Stuart/A-7513-2009 NR 41 TC 5 Z9 5 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 267 EP 272 DI 10.1007/BF02765701 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800001 ER PT J AU BussmannHolder, A Bishop, AR AF BussmannHolder, A Bishop, AR TI Cooperative polaronic and electronic effects in high-temperature superconductors SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE cuprates; electron-phonon interaction; polarons AB An anharmonic electron-phonon interaction model is used to study lattice and electronic effects of high-temperature superconductors (HTSC), Due to higher-order electron density-multiphonon interactions the effective electron-phonon coupling experiences a strong q-dependence which leads to incommensurations, stripes, and tweeds in the dynamical ionic displacement pattern. Simultaneously these terms induce strong interband interactions which enhance the intraband electron-hole pair formation and contribute substantially to the high superconducting transition temperatures T-c. The resulting superconducting gap structure is highly anisotropic, and using its energy-dependent structure the experimentally observed electromagnetic response is calculated and well reproduced. C1 LOS ALAMOS NATL LAB,DIV THEORET,MSB262,LOS ALAMOS,NM 87545. RP BussmannHolder, A (reprint author), MAX PLANCK INST FESTKORPERFORSCH,HEISENBERGSTR 1,D-70569 STUTTGART,GERMANY. NR 14 TC 4 Z9 4 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 289 EP 291 DI 10.1007/BF02765705 PG 3 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800005 ER PT J AU Conradson, SD DeLeon, JM Bishop, AR AF Conradson, SD DeLeon, JM Bishop, AR TI Local phase separation in Tl-based oxide superconductors SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE phase separation; thallium cuprates; XAFS ID ABSORPTION FINE-STRUCTURE; CUO2 PLANE; TC; LA1.85SR0.15CUO4; DIFFRACTION; SCATTERING; YBA2CU3O7 AB We present the results of the analysis of Cu K-edge X-ray absorption fine structure (XAFS) on Tl2Ba2CUO6, which show a complex Cu-O pair distribution function with multiple Cu-O bondlengths in the CuO2 planes, implying local phase separation in this material. Based on these results we propose a model of the local structure of these Tl-based superconductors. We present the formalism used to extract a pair distribution function from XAFS from a model interatomic potential, associating a dynamic time scale to fluctuations between different bond lengths. These copper-oxygen bondlengths are compared with those found in Bi2Sr2CaCu2O8+y, La1.85Sr0.15Cu2O4, and YBa2Cu3O7. C1 CTR INVEST & ESTUDIOS AVANZADOS,MERIDA 97310,YUCATAN,MEXICO. RP Conradson, SD (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 15 TC 18 Z9 18 U1 0 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 329 EP 332 DI 10.1007/BF02765713 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800013 ER PT J AU Yamada, K Lee, CH Wada, J Kurahashi, K Kimura, H Endoh, Y Hosoya, S Shirane, G Birgeneau, RJ Kastner, MA AF Yamada, K Lee, CH Wada, J Kurahashi, K Kimura, H Endoh, Y Hosoya, S Shirane, G Birgeneau, RJ Kastner, MA TI Spatial modulation of low-frequency spin fluctuations in hole-doped La2CuO4 SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE La2CuO4; spin fluctuations; neutron scattering ID MAGNETIC FLUCTUATIONS; LA2-XSRXCUO4; EXCITATIONS; LA1.85SR0.15CUO4 AB Systematic neutron scattering measurements have been performed on the Sr-doped La2-xSrxCuO4 to study the doping dependence of spatially modulated dynamical spin correlations or so-called incommensurate spin fluctuations. The modulated spin correlations appear beyond x approximate to 0.05 which is close to the lower boundary of the superconducting phase. First evidence was observed for the linear relation between the degree of spatial modulation or the incommensurability delta(x) and the maximum T-c at x. We present a universal curve for delta(x) by adding data front other La2CuO4 systems such as oxygen-doped superconductors, oxygen-reduced or Zn-substituted nonsuperconductors, and La1.6-xNd0.4SrxCuO4. C1 YAMANASHI UNIV,FAC ENGN,INST INORGAN PHYS,KOFU,YAMANASHI 400,JAPAN. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP Yamada, K (reprint author), TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 98077,JAPAN. RI Yamada, Kazuyoshi/C-2728-2009 NR 15 TC 23 Z9 23 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 343 EP 347 DI 10.1007/BF02765716 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800016 ER PT J AU Wochner, P Xiong, X Moss, SC AF Wochner, P Xiong, X Moss, SC TI Stripe correlation of tilts and superconductivity in La2CuO4+delta SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE stripe correlation; La2CuO4; superconductivity ID ELECTRONIC PHASE-SEPARATION; ELECTROCHEMICAL OXIDATION; LOCAL-STRUCTURE; MAGNETISM; SPINS; HOLES AB In single crystal La2CuO4+delta, delta approximate to 0.015, c-axis interstitial oxygen ordering (staging) in the oxygen-rich phase of the phase-separated sample was observed through satellite peaks in the neutron scattering which first appear at 250 K. If the sample is cooled through the temperature region around 210 K over a period of several hours, these satellite peaks show splitting in the a*-direction. This first-order phase transition involves a periodic one-dimensional modulation of the in-plane order. Microscopic modeling leads to a picture where the excess oxygen, and therefore also the doped holes, order in stripes along the a-direction in addition to staging along the c-direction This ordering in stripes can be regarded as a continuation of the phase separation but now on a local scale, leading to a local increase in oxygen and hole density. This increase can account for the increase of the superconducting T-c of 2.5 K observed in our sample and also for many previously reported annealing experiments. C1 UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. UNIV HOUSTON,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77204. RP Wochner, P (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 35 TC 6 Z9 6 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 367 EP 372 DI 10.1007/BF02765720 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800020 ER PT J AU Zachar, O Kivelson, SA Emery, VJ AF Zachar, O Kivelson, SA Emery, VJ TI High-temperature pairing in stripes SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE stripes; pairing; Josephson coupling ID PHASE-SEPARATION; MODEL; SUPERCONDUCTIVITY; SYSTEMS AB That the superconducting transition in underdoped high temperature superconductors is controlled by phase ordering, implies that pairing is a local phenomenon that occurs on an intermediate length scale, and typically at a temperature above T-c. The discovery of local stripe order in the LSCO family of high temperature superconductors, along with the theoretical suggestion that such structures are a general feature of doped antiferromagnets lead us further to propose that in fact pairing occurs in the vicinity of an individual stripe. The transition to a superconducting state then follows at lower temperature due td Josephson coupling between stripes. In this paper we review our microscopic model of high temperature pairing on individual stripes. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Zachar, O (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90095, USA. NR 14 TC 6 Z9 6 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 373 EP 378 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800021 ER PT J AU Mook, HA Chakoumakos, BC AF Mook, HA Chakoumakos, BC TI Incommensurate fluctuations in Bi2Sr2CaCu2O8 SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE Bi2Sr2CaCu2O8; incommensurate fluctuations; neutron scattering ID FERMI-SURFACE AB A special neutron scattering technique has been used to discover an incommensurate fluctuation in Bi2Sr2CaCu2O8 that appears below T-c. The fluctuation is identified as a dynamic charge density wave since its scattering intensity appears to increase with increasing momentum transfer. The fluctuation is found at a wavevector near 2k(F) and could be associated with a dynamic stripe phase. RP Mook, HA (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37830, USA. RI Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 7 TC 6 Z9 6 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 389 EP 392 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800024 ER PT J AU Sigmund, E Hizhnyakov, VH Nevedrov, D Bill, A AF Sigmund, E Hizhnyakov, VH Nevedrov, D Bill, A TI Anisotropy of the superconducting gap in the presence of electron-phonon and coulomb interactions SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE Electron-phonon interaction; gap anisotropy; Coulomb repulsion ID ORDER-PARAMETER; YBA2CU3O7-DELTA; SYMMETRY; STATE; PB AB d-wave and s-wave-type solutions of the BCS gap equations are studied numerically with account of long-range and short-range interaction with optical phonon and Coulomb repulsion. It is found that for realistic values of parameters the maximal value of the gap is determined mainly by unscreened long-range interactions of charge carriers with long-wave A(Ig)- and B-Ig- phonons. The type of the stable solution (d-wave or s-wave) essentially depends on the strength of the Coulomb repulsion as well as on the strength of other short-range interaction potentials. The conclusion is drawn that in some members of cuprate superconductors Cooper pairs may have d-wave symmetry while in others the symmetry may be of aniso-tropic s-wave type. C1 TARTU STATE UNIV,INST THEORET PHYS,EE-2400 TARTU,ESTONIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Sigmund, E (reprint author), TECH UNIV COTTBUS,INST PHYS,POSTFACH 101344,D-03013 COTTBUS,GERMANY. NR 26 TC 2 Z9 2 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 441 EP 446 DI 10.1007/BF02765734 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800034 ER PT J AU vonZimmermann, M Vigliante, A Frello, T Madsen, J Buttrey, DJ Andersen, NH Schneider, JR Gibbs, D Tranquada, JM AF vonZimmermann, M Vigliante, A Frello, T Madsen, J Buttrey, DJ Andersen, NH Schneider, JR Gibbs, D Tranquada, JM TI X-ray scattering study of charge scattering associated with stripe order in La1.775Sr0.225NiO4 SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Stripes, Lattice Stabilities, and High-Temperature Superconductivity CY DEC 08-12, 1996 CL ROME, ITALY DE La1.775; Sr0.225; NiO4; X-ray scattering; stripe order ID INCOMMENSURATE MAGNETIC CORRELATIONS; HOLES; SPINS; LA2NIO4.125 AB In this paper we report the first observation of stripe correlations of holes in hole-doped La2NiO4 by X-ray diffraction. The experiment was performed in Laue geometry at the hard X-ray beamline BW5 at HASYLAB on a crystal of La1.775Sr0.225NiO4 previously studied by neutron diffraction. Temperature dependences of the intensities and wave vectors of the charge-density-modulation peaks were characterized and found to be in good agreement with the neutron scattering results. Interestingly, weak, temperature-dependent scattering was also observed at positions consistent with nonresonant X-ray magnetic scattering from the spin correlations; however, a definitive determination of its origin remains lacking. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. RISO NATL LAB,DEPT SOLID STATE PHYS,DK-4000 ROSKILDE,DENMARK. UNIV DELAWARE,DEPT CHEM ENGN,NEWARK,DE 19716. RP vonZimmermann, M (reprint author), DESY,HAMBURGER SYNCHROTRONSTRAHLUNGSLAB HASYLAB,NOTKESTR 85,D-22603 HAMBURG,GERMANY. RI Tranquada, John/A-9832-2009; Andersen, Niels/A-3872-2012 OI Tranquada, John/0000-0003-4984-8857; NR 11 TC 3 Z9 3 U1 1 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD AUG PY 1997 VL 10 IS 4 BP 447 EP 450 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA YD618 UT WOS:A1997YD61800035 ER PT J AU Chick, LA Liu, J Stevenson, JW Armstrong, TR McCready DE Maupin, GD Coffey, GW Coyle, CA AF Chick, LA Liu, J Stevenson, JW Armstrong, TR McCready DE Maupin, GD Coffey, GW Coyle, CA TI Phase transitions and transient liquid-phase sintering in calcium-substituted lanthanum chromite SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID DOPED LANTHANUM; AIR AB This paper investigates sintering and phase transitions of La0.7CaxCrO3 (0.25 less than or equal to x less than or equal to 0.35), a material useful as electrical interconnections in solid ol;ide fuel cells. Heating of the quenched, metastable single-phase chromite resulted in exsolution of CaCrO4 due to Ca solubility limitations below 1200 degrees C. A transient liquid phase formed between 850 degrees and 1000 degrees C as the CaCrO4 melted, causing partial densification in materials having 0.25 < x < 0.30. A slight increase in Ca content induced an additional liquid-phase sintering event, likely due to melting of Ca-3(CrO4)(2), which facilitated near-complete densification by 1250 degrees C. After enhancing sintering, the secondary phases redissolved into the chromite. RP PACIFIC NW LAB, DEPT CHEM & MAT SCI, RICHLAND, WA 99352 USA. NR 38 TC 82 Z9 90 U1 2 U2 10 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 1997 VL 80 IS 8 BP 2109 EP 2120 PG 12 WC Materials Science, Ceramics SC Materials Science GA XQ331 UT WOS:A1997XQ33100022 ER PT J AU Dreon, DM Krauss, RM AF Dreon, DM Krauss, RM TI Diet-gene interactions in human lipoprotein metabolism SO JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION LA English DT Article; Proceedings Paper CT 35th Annual Meeting of the American-College-of-Nutrition CY OCT 15, 1995 CL WASHINGTON, D.C. SP Amer Coll Nutr DE diet; genetics; lipoproteins; coronary disease ID APOLIPOPROTEIN-E POLYMORPHISM; CORONARY-ARTERY DISEASE; HIGH-DENSITY-LIPOPROTEINS; A-IV POLYMORPHISM; PLASMA TRIGLYCERIDE CONCENTRATION; CYSTEINE-ARGININE INTERCHANGE; SERUM-CHOLESTEROL LEVELS; ESTER TRANSFER PROTEIN; LDL PARTICLE-SIZE; B-GENE AB Genetic variation can influence the effects of hypocholesterolemic dietary interventions on lipoproteins involved in coronary artery disease (CAD). Individuals with the E4 allelic variant of the apo E gene exhibit greater low-density lipoprotein (LDL) cholesterol reductions on low-fat, low-cholesterol diets than subjects with other alleles. Another apolipoprotein structural variant, apo A-IV-2, attenuates the response of LDL cholesterol to dietary cholesterol. Other studies have associated lipoprotein response to dietary modifications with DNA polymorphisms in the genes for apo B and the LDL receptor, and in the promoter region of the apo A-I gene. Studies in our laboratory involving variation in dietary fat and carbohydrate intake have demonstrated that alleles at the apo E gene locus are associated with changes in large, buoyant but not smaller, denser LDL subclasses. On the other hand, a low-fat diet induces a reduction in small, dense LDL in individuals with a genetically influenced metabolic profile characterized by a predominance of these particles. Moreover, reductions in LDL cholesterol and apo B in these subjects are greater than in the majority of subjects with larger LDL. Since in humans a predominance of small LDL signifies a higher risk for coronary artery disease than that associated with larger LDL, metabolic and genetic factors contributing to the small LDL trait may account for a substantial portion of the coronary risk benefit attributed to reduced-fat diets. Studies in large population groups or in suitable animal models will be necessary to determine the impact of genetic influences on dietary response affecting lipoprotein metabolism and their interactions with other environmental and hormonal factors. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Dept Mol & Nucl Med, Berkeley, CA 94720 USA. Childrens Hosp, Oakland Res Inst, Oakland, CA 94609 USA. RP Krauss, RM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Dept Mol & Nucl Med, Rm 465,1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL 18574] NR 146 TC 41 Z9 42 U1 0 U2 0 PU AMER COLL NUTRITION PI NEW YORK PA C/O HOSP. JOINT DIS. 301 E. 17TH ST., NEW YORK, NY 10003 USA SN 0731-5724 J9 J AM COLL NUTR JI J. Am. Coll. Nutr. PD AUG PY 1997 VL 16 IS 4 BP 313 EP 324 PG 12 WC Nutrition & Dietetics SC Nutrition & Dietetics GA YT620 UT WOS:000071625300004 PM 9263180 ER PT J AU Buchheit, RG Grant, RP Hlava, PF Mckenzie, B Zender, GL AF Buchheit, RG Grant, RP Hlava, PF Mckenzie, B Zender, GL TI Local dissolution phenomena associated with S phase (Al2CuMg) particles in aluminum alloy 2024-T3 SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ATOMIC-FORCE MICROSCOPY; CORROSION; CU AB Second-phase particles in Al-4.4Cu-15Mg-0.6 Mn (2024-T3) were characterized by size and chemistry using scanning electron microscopy and associated electron-beam microanalysis methods. It was found that approximately 60% of par tides greater than about 0.5 to 0.7 mu m were Al2CuMg (the S phase). This fraction corresponded to 2.7% of the total surface area. S phase particles appeared to be active with respect to the matrix phase, consistent with open-circuit potentials reported in the literature for Al2CuMg. The compound exhibited severe dealloying which resulted in the formation of Cu-rich particle remnants. Some particle remnants remained largely intact and induced pitting at their periphery once ennobled by dealloying. Other particle remnants decomposed into 10 to 100 nm Cu clusters that became detached from the alloy surface and were dispersed by mechanical action of growing corrosion product or solution movement. This observation suggests that nonfaradaic liberation of Cu from corroding 2024-T3 surfaces is possible, and provides one plausible explanation for how Cu can be redistributed across the surface by a pitting process which occurs at potentials that are hundreds of millivolts negative of the reduction potential for Cu. RP Buchheit, RG (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 19 TC 462 Z9 477 U1 14 U2 110 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2621 EP 2628 DI 10.1149/1.1837874 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300018 ER PT J AU Rao, L Newman, J AF Rao, L Newman, J TI Heat-generation rate and general energy balance for insertion battery systems SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID IRON SULFIDE BATTERY; LITHIUM/POLYMER BATTERY; DISCHARGE BEHAVIOR; LITHIUM-ALUMINUM; CELL; ELECTRODE; OPTIMIZATION AB A general energy balance has been developed for insertion battery systems by using enthalpy potentials. This leads to a new calculation method for the heat-generation rater The same result is also derived from an alternative model based on local heat generation in an electrochemical cell. A new concept, the effective open-circuit potential of an insertion battery, was proposed to characterize the open-circuit state of the battery during galvanostatic discharge. Simulation results for are presented heat generation in a lithium cell under galvanostatic discharge. The analysis of these results focuses on effects of the shape of the open-circuit potential and ohmic losses in the electrolyte in the porous cathode. It is shown that a single reaction may look like two reactions due to the presence of two plateaus in the open-circuit potential. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. RP Rao, L (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720, USA. RI Newman, John/B-8650-2008 OI Newman, John/0000-0002-9267-4525 NR 22 TC 124 Z9 126 U1 7 U2 46 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2697 EP 2704 DI 10.1149/1.1837884 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300028 ER PT J AU Ma, B Park, JH Balachandran, U AF Ma, B Park, JH Balachandran, U TI Analysis of oxygen transport and stoichiometry in mixed-conducting SrFeCo0.5Ox by conductivity and thermogravimetric analysis SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CHEMICAL DIFFUSION-COEFFICIENT; PEROVSKITE-TYPE OXIDES; ELECTRICAL-CONDUCTIVITY; RELAXATION; OXIDATION; KINETICS; METHANE AB The conductivity and weight changes of SrFeCo0.5Ox in various different oxygen partial pressures (p(o2)) were measured simultaneously by the four-point de method and a thermogravimetric analysis apparatus, respectively. The apparent oxygen diffusion coefficients were derived from the weight and conductivity relaxation experiments by abruptly changing the p(o2) in the surrounding atmosphere and monitoring the change of weight and conductivity as functions of relaxation time. At 950 degrees C in air, the obtained apparent oxygen diffusion coefficient of SrFeCo0.5Ox is approximate to 1 x 10(-6) cm(2)s(-1). Conductivity increases while the weight decreases with increasing temperature within our experimental p(o2) range (1 greater than or equal to p(o2) greater than or equal to 10(-18) atm), and the activation energy decreases while conductivity increases with increasing p(o2). The p(o2)-dependent conducting behavior can be understood by considering the trivalent-to-divalent transition of transition metal ions in the sample. The oxygen stoichiometry of SrFeCo0.5Ox in air is x = 3 at 950 degrees C. RP Ma, B (reprint author), ARGONNE NATL LAB,DIV ENERGY TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Ma, Beihai/I-1674-2013 OI Ma, Beihai/0000-0003-3557-2773 NR 28 TC 15 Z9 15 U1 0 U2 8 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2816 EP 2823 DI 10.1149/1.1837900 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300044 ER PT J AU Vartuli, CB Pearton, SJ Lee, JW MacKenzie, JD Abernathy, CR Shul, RJ Constantine, C Barratt, C AF Vartuli, CB Pearton, SJ Lee, JW MacKenzie, JD Abernathy, CR Shul, RJ Constantine, C Barratt, C TI Inductively coupled plasma etching of III-V nitrides in CH4/H-2/Ar and CH4/H-2/N-2 chemistries SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID MOLECULAR-BEAM EPITAXY; GALLIUM NITRIDE; GAN; INN; HYDROGEN; GROWTH; ALN AB Inductively coupled plasma (ICP) etching of GaN, AlN, InN, InGaN, and InAlN was investigated in CH4/H-2/Ar and CH4/H-2/N-2 plasmas as a function of dc bias, ICP power, and pressure. The etch rates were generally quite low, as is common for III-nitrides in CH4-based chemistries. In CH4/H-2/Ar plasmas, the etch rates increased with increasing de bias. At low radio frequency power (150 W), the etch rates increased with increasing ICP power, while at 350 W radio frequency power, a peak was found between 500 and 750 W ICP power. The de bias was found to increase with increasing pressure. The etch rates in the CH4/H-2/N-2 chemistry were significantly lower, with a peak at 500 W ICP power. The etched surfaces were smooth, while selectivities of etch were less than or equal to 6 for InN over GaN, AlN, InGaN, and InAlN under all conditions. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. PLASMATHERM IP,ST PETERSBURG,FL 33716. RP Vartuli, CB (reprint author), UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611, USA. NR 18 TC 22 Z9 22 U1 1 U2 4 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2844 EP 2847 DI 10.1149/1.1837905 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300049 ER PT J AU Besser, RS Louris, PJ Musket, RG AF Besser, RS Louris, PJ Musket, RG TI Chemical etch rate of plasma-enhanced chemical vapor deposited SiO2 films - Effect of deposition parameters SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID SILICON DIOXIDE; CVD AB One of the most used diagnostics for characterizing silica thin films is the etch rate (ER) in acidic, fluoride-based solutions. The ER measurement is relatively easy, fast, and cheap, which makes it attractive as an in-process monitor. For microelectronics, this monitor is extremely useful when it indicates the electrically insulating qualities of the film. In this paper we consider the chemical etching behavior of plasma-enhanced chemical vapor deposited SiO2 thin films prepared over wide ranges of deposition parameters. The ER, breakdown field strength, refractive index, density, oxygen to silicon ratio, and residual stress of the resulting films showed wide variation. Correlations of these properties to the deposition parameters showed that the ER is an excellent monitor for breakdown strength and electrically insulating properties of these films. Slow etching rate was found to result from a higher substrate temperature, higher pressure, lower silane flow and higher power. While many physical features of the film affect ER, we found that variations in the porosity of the film were dominating. Consistent with this picture, greater magnitudes of compressive stress resulted in slower ER, but only on relatively porous films deposited at low temperature. Composition did not have an appreciable effect. C1 SAN JOSE CHRISTIAN COLL,DEPT SCI & MATH,SAN JOSE,CA 95108. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Besser, RS (reprint author), CANDESCENT TECHNOL CORP,SAN JOSE,CA 95119, USA. NR 21 TC 8 Z9 8 U1 2 U2 10 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2859 EP 2864 DI 10.1149/1.1837908 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300052 ER PT J AU Zhou, D Krauss, AR Corrigan, TD McCauley, TG Chang, RPH Gruen, DM AF Zhou, D Krauss, AR Corrigan, TD McCauley, TG Chang, RPH Gruen, DM TI Microstructure and field emission of nanocrystalline diamond prepared from C-60 precursors SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID MICROWAVE PLASMAS; FILM GROWTH; HYDROGEN; STATES; ARGON AB Cold cathode electron field emission from nanocrystalline diamond thin films produced by microwave plasma-enhanced CVD with C-60 as the growth precursor has been observed. The lowest onset field obtained is about 2 V/mu m, and a 4 V/mu m field is required to emit a current density of 0.4 mA/cm(2). It has been found that hydrogen content of the plasma, which can be Varied over a wide range, strongly affects the microstructure and electron field emission properties of the nanocrystalline diamond thin films. This is an important new development which allows one to exercise powerful control over many properties of diamond films. Based on TEM characterization and field emission measurements, the effects of the structural defects and the orientations of the diamond grains on the field emission properties are discussed. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. RP Zhou, D (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 21 TC 20 Z9 20 U1 0 U2 0 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP L224 EP L228 DI 10.1149/1.1837864 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300008 ER PT J AU Cheng, CZ AF Cheng, CZ TI Energetic particle physics with applications in fusion and space plasmas SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 1st Asia-Pacific Plasma Theory Conference (APPTC 96) CY AUG 21-23, 1996 CL TAEDOK SCI & CULTURE CTR, TAEJON, SOUTH KOREA SP Korea Sci & Engn Fdn, Asia Pacific Ctr Theoret Phys, Korea Bas Sci Inst HO TAEDOK SCI & CULTURE CTR ID INDUCED ALFVEN EIGENMODES; AXISYMMETRICAL TOROIDAL PLASMAS; WAVES; INSTABILITIES; EXCITATION; MAGNETOSPHERE; EQUILIBRIA; STABILITY; TOKAMAKS; MODES AB Energetic particle physics is the study of the effects of energetic particles on ''collective'' electromagnetic (EM) instabilities and energetic particle transport in plasmas. Anomalously large energetic particle transport is often caused by low frequency MHD instabilities, which are driven by these energetic particles in the presence of a much denser background of thermal particles. The theory of collective energetic particle phenomena studies complex wave-particle interactions in which particle kinetic physics involving small spatial and fast temporal scales can strongly affect the MI-ID structure and long-time behavior of plasmas. The difficulty of modeling kinetic-MHD multiscale coupling processes stems from the disparate scales which are traditionally analyzed separately: the macroscale MHD phenomena are studied using the fluid MHD framework, while microscale kinetic phenomena are best described by complicated kinetic theories. We have developed a kinetic-MHD model that properly incorporates major particle kinetic effects into the MHD fluid description. For tokamak plasmas a nonvariational kinetic-MHD stability code, the NOVA-K code, has been successfully developed and applied to study problems such as the excitation of fishbone and Toroidal Alfven Eigenmodes (TAE) and the sawtooth stabilization by energetic ions in tokamaks. In space plasmas we have employed the kinetic-MHD model to study the energetic particle effects on the ballooning-mirror instability which explains the multisatellite obervation of the stability and field-aligned structure of compressional Pc 5 waves in the magnetospheric ring current plasma. RP Cheng, CZ (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Cheng, Chio/K-1005-2014 NR 32 TC 1 Z9 1 U1 0 U2 1 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD AUG PY 1997 VL 31 SU S BP S127 EP S138 PG 12 WC Physics, Multidisciplinary SC Physics GA XU198 UT WOS:A1997XU19800008 ER PT J AU Wright, LD Sherwood, CR Sternberg, RW AF Wright, LD Sherwood, CR Sternberg, RW TI Field measurements of fairweather bottom boundary layer processes and sediment suspension on the Louisiana inner continental shelf SO MARINE GEOLOGY LA English DT Article DE bottom boundary layer; continental shelf; Mississippi Delta; sediment transport ID MIDDLE ATLANTIC BIGHT; STRESS; WAVE; BED; TRANSPORT; MOVEMENT; STORMS; MODEL AB Field measurements of bottom boundary layer and sediment-transport processes were made on the Louisiana inner continental shelf in spring 1992 at a depth of 15.5 m, and in spring and summer 1993 at a depth of 20.5 m. Two different wave-current boundary layer/sediment-transport models were applied to the measured near-bed flows. In addition, the log-profile method was applied to estimate hydraulic roughness and bed stress. Consistent with the results of others, our measurements show that near-bed flows were very weak under non-storm conditions. Bed stresses were typically too low to resuspend bed sediments. However, the advection of high-turbidity layers or plumes past the instrumentation apparently caused a sustained period of high suspended sediment concentration throughout the log layer in spring 1993, In the absence of wave activity or high suspended sediment concentrations, boundary layer profiles showed the bed to have been hydraulically very smooth with z(o)' < 0.1 cm. However, wave agitation, combined with increased suspended sediment concentration caused hydraulically rough conditions with z(o)' < 0.1 cm. (C) 1997 Elsevier Science B.V. C1 BATTELLE MARINE SCI LAB, SEQUIM, WA 98382 USA. UNIV WASHINGTON, SCH OCEANOG, SEATTLE, WA 98195 USA. RP Wright, LD (reprint author), VIRGINIA INST MARINE SCI, COLL WILLIAM & MARY, SCH MARINE SCI, GLOUCESTER POINT, VA 23062 USA. NR 21 TC 29 Z9 31 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-3227 J9 MAR GEOL JI Mar. Geol. PD AUG PY 1997 VL 140 IS 3-4 BP 329 EP 345 DI 10.1016/S0025-3227(97)00032-7 PG 17 WC Geosciences, Multidisciplinary; Oceanography SC Geology; Oceanography GA XZ781 UT WOS:A1997XZ78100007 ER PT J AU George, EP Liu, CT Horton, JA Sparks, CJ Kao, M Kunsmann, H King, T AF George, EP Liu, CT Horton, JA Sparks, CJ Kao, M Kunsmann, H King, T TI Characterization, processing, and alloy design of NiAl-based shape memory alloys (Reprinted from Materials Characterization, vol 32, pg 139-160, 1994) SO MATERIALS CHARACTERIZATION LA English DT Reprint ID THERMOELASTIC MARTENSITIC-TRANSFORMATION; MECHANICAL-PROPERTIES; AL ALLOYS; PREMARTENSITIC MICROSTRUCTURES; ELECTRON-MICROSCOPY; BETA-2 PHASE; NI5AL3; DUCTILITY; NI-36.8 AB The microstructures and phase transformations in binary Ni-Al, ternary Ni-Al-Fe, and quaternary Ni-Al-Fe-Mn shape memory alloys (SMAs) were investigated by light and electron microscopy, electron and X-ray diffraction, and differential scanning calorimetry. The effects of alloying additions (B, Fe, and Mn) on martensite stability, shape recovery, and tensile ductility were also studied. NiAl-based SMAs can be made ductile by alloying with B for enhanced grain boundary cohesion and Fe for improved bulk properties. Iron has the undesirable effect that it decreases the martensite --> austenite transformation temperatures (A(p)) Fortunately, A(p) can be increased by decreasing the "equivalent" Al content of the alloy. In this way, a high A(p) temperature of similar to 190 degrees C has been obtained without sacrificing ductility. Recoverable strains of similar to 0.7% have been obtained in a Ni-Al-Fe alloy with A(p) temperature of similar to 140 degrees C. Manganese additions (2-10%) lower A(p), degrade hot workability, and decrease room temperature ductility. Good-quality, ductile SMA ribbons have been produced by melt spinning. However, additional alloy design is required to suppress the aging-induced embrittlement caused by Ni5Al3 formation. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Johnson Controls Inc, Milwaukee, WI 53209 USA. Eaton Corp, Milwaukee, WI 53216 USA. RP George, EP (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI George, Easo/L-5434-2014; OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 43 TC 19 Z9 23 U1 0 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-5803 J9 MATER CHARACT JI Mater. Charact. PD AUG-NOV PY 1997 VL 39 IS 2-5 BP 665 EP 686 DI 10.1016/S1044-5803(97)00149-6 PG 22 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA ZK797 UT WOS:000073364600030 ER PT J AU Kass, MD Cecala, DM AF Kass, MD Cecala, DM TI Enhanced sinterability of alumina particles by pretreating in liquid ammonia SO MATERIALS LETTERS LA English DT Article DE alumina; ammonia; powder; sintering; Al2O3 ID HIGH-PURITY ALUMINA; POWDERS AB The sinterability of high purity alumina powders was enhanced by ultrasonication in liquid ammonia. The surfaces of the resulting powders contained agglomerated regions of submicron-sized particles that were metallic in appearance. When heated to 1400 degrees C, these particles densified into a solid with observable grain bonding and necking. (C) 1997 Elsevier Science B.V. C1 OAK RIDGE Y-12 PLANT,DEV DIV,OAK RIDGE,TN 37831. RP Kass, MD (reprint author), OAK RIDGE NATL LAB,ENGN TECHNOL DIV,OAK RIDGE,TN 37831, USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD AUG PY 1997 VL 32 IS 2-3 BP 55 EP 58 DI 10.1016/S0167-577X(97)00010-4 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XV877 UT WOS:A1997XV87700001 ER PT J AU BarAd, S Chemla, DS AF BarAd, S Chemla, DS TI Quantum kinetics regime during and immediately after laser excitation of semiconductors SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT 6th NEC Symposium on Quantum Optical Phenomena in Spatially Confined Materials - Fundamental Approaches to New Material Phases CY OCT 13-17, 1996 CL KARUIZAWA, JAPAN SP NEC Corp DE semiconductors; quantum kinetics; thermalization; short pulse spectroscopy ID FEMTOSECOND CARRIER DYNAMICS; PULSE-EXCITED SEMICONDUCTOR; LO-PHONON SCATTERING; GAAS; RELAXATION; MEMORY; SINGULARITIES AB We investigated carrier dynamics in the semiconductor GaAs, during and just after creation by approximate to 30 fs laser pulses, much shorter than the phonon and plasma time scales. We observed a quasi-instantaneous spread of the carrier population in momentum-energy space, that is not even qualitatively consistent with Boltzmann kinetics. The observations are, however, in qualitative agreement with quantum kinetic theories of carrier-carrier and carrier-phonon scattering. (C) 1997 Elsevier Science S.A. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 20 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD AUG 1 PY 1997 VL 48 IS 1-2 BP 83 EP 87 DI 10.1016/S0921-5107(97)00085-8 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA XY086 UT WOS:A1997XY08600015 ER PT J AU Kim, D Libon, IH Voelkmann, C PetrovaKoch, V Shen, YR AF Kim, D Libon, IH Voelkmann, C PetrovaKoch, V Shen, YR TI Multiphoton excitations in porous silicon SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT 6th NEC Symposium on Quantum Optical Phenomena in Spatially Confined Materials - Fundamental Approaches to New Material Phases CY OCT 13-17, 1996 CL KARUIZAWA, JAPAN SP NEC Corp DE porous Si; multiphoton excitation; photoluminescence ID OPTICAL-PROPERTIES; LUMINESCENCE; SI AB Photoluminescence was used to study multiphoton excitations in porous Si. With picosecond exciting pulses in the mid-infrared, even a nine-photon excitation process could be readily observed. Excitations are likely of the multi-resonant, multi-step type, with the surface states involved as intermediate resonant levels. Absorption by vibrational transitions of surface species could lead to resonant features in the excitation spectrum. (C) 1997 Elsevier Science S.A. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. TECH UNIV MUNICH,DEPT PHYS,D-8046 GARCHING,GERMANY. RI Kim, Doseok/J-8776-2013 NR 12 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD AUG 1 PY 1997 VL 48 IS 1-2 BP 103 EP 107 DI 10.1016/S0921-5107(97)00088-3 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA XY086 UT WOS:A1997XY08600018 ER PT J AU Fountos, G Yasumura, S Glaros, D AF Fountos, G Yasumura, S Glaros, D TI The skeletal calcium/phosphorus ratio: A new in vivo method of determination SO MEDICAL PHYSICS LA English DT Article DE Ca/P ratio; photon absorptiometry; bone minerals ID INFLAMMATION-MEDIATED OSTEOPENIA; BONE; COEFFICIENTS; ATTENUATION; MASS AB We describe a new method for assessing the Ca/P ratio of bone in vivo using gamma-ray photon absorptiometry. The theoretical approach of the method and the estimation of the variance are presented. Two radiation sources, Gd-153 (100 keV), and I-125 (27.5 keV), and a germanium detector were used to determine this ratio. Measurements were made on bone phantoms with different Ca/P ratios; also, the ratio was measured on lamb and sheep tibias, rabbit tibias, and human fingers. Since the accuracy of the method is affected by the amount of fat and collagen in the measurement field, the effect of collagen and fat on the measurements also was investigated. In all cases, the precision of the method, expressed as the coefficient of variation (CV): 100 x standard deviation/mean, was near to the theoretical one, ranging from 1.8% to 3.2%. For human fingers, the CV was 3.2%, a value near to the theoretical 2.9% with a dose to the skin ranging from 0.044 to 0.066 mGy, depending on the width of the finger. (C) 1997 American Association of Physicists in Medicine. C1 BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP Fountos, G (reprint author), UNIV IOANNINA,SCH MED,MED PHYS LAB,GR-45110 IOANNINA,GREECE. NR 24 TC 34 Z9 34 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0094-2405 J9 MED PHYS JI Med. Phys. PD AUG PY 1997 VL 24 IS 8 BP 1303 EP 1310 DI 10.1118/1.598152 PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA XR369 UT WOS:A1997XR36900013 PM 9284254 ER PT J AU Tarsounas, M Pearlman, RE Gasser, PJ Park, MS Moens, PB AF Tarsounas, M Pearlman, RE Gasser, PJ Park, MS Moens, PB TI Protein-protein interactions in the synaptonemal complex SO MOLECULAR BIOLOGY OF THE CELL LA English DT Article ID INTACT YEAST-CELLS; HIGH-EFFICIENCY TRANSFORMATION; SISTER-CHROMATID SEPARATION; 2 MAJOR COMPONENTS; CROSSOVER INTERFERENCE; PROTEOLYTIC PATHWAY; CHROMOSOME SYNAPSIS; ANAPHASE TRANSITION; LATERAL ELEMENTS; FISSION YEAST AB In mammalian systems, an approximately M-r 30,000 Cor1 protein has been identified as a major component of the meiotic prophase chromosome cores, and a M-r 125,000 Syn1 protein is present between homologue cores where they are synapsed and form the synaptonemal complex (SC). Immunolocalization of these proteins during meiosis suggests possible home-and heterotypic interactions between the two as well as possible interactions with as yet unrecognized proteins. We used the two-hybrid system in the yeast Saccharomyces cerevisiae to detect possible protein-protein associations. Segments of hamster Cor1 and Syn1 proteins were tested in various combinations for home-and heterotypic interactions. In the case of Cor1, homotypic interactions involve regions capable of coiled-coil formation, observation confirmed by in vitro affinity coprecipitation experiments. The two-hybrid assay detects no interaction of Cor1 protein with central and C-terminal fragments of Syn1 protein and no homotypic interactions involving these fragments of Syn1. Hamster Cor1 and Syn1 proteins both associate with the human ubiquitin-conjugating enzyme Hsubc9 as well as with the hamster Ubc9 homologue. The interactions between SC proteins and the Ubc9 protein may be significant for SC disassembly, which coincides with the repulsion of homologs by late prophase I, and also for the termination of sister centromere cohesiveness at anaphase II. C1 YORK UNIV,DEPT BIOL,TORONTO,ON M3J 1P3,CANADA. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. OI Gasser, Paul/0000-0002-2092-6068 FU NCI NIH HHS [CA71630] NR 62 TC 38 Z9 41 U1 0 U2 2 PU AMER SOC CELL BIOLOGY PI BETHESDA PA PUBL OFFICE, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD AUG PY 1997 VL 8 IS 8 BP 1405 EP 1414 PG 10 WC Cell Biology SC Cell Biology GA XU245 UT WOS:A1997XU24500002 PM 9285814 ER PT J AU Yu, ET Pennycook, SJ AF Yu, ET Pennycook, SJ TI Nanoscale characterization of materials SO MRS BULLETIN LA English DT Editorial Material C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Yu, ET (reprint author), UNIV CALIF SAN DIEGO,DEPT ELECT & COMP ENGN,9500 GILMAN DR,MAIL CODE 0407,LA JOLLA,CA 92093, USA. RI Yu, Edward/A-3515-2017 OI Yu, Edward/0000-0001-9900-7322 NR 0 TC 3 Z9 3 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD AUG PY 1997 VL 22 IS 8 BP 17 EP 21 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XR891 UT WOS:A1997XR89100020 ER PT J AU Salmeron, M Xu, L Hu, J Dai, Q AF Salmeron, M Xu, L Hu, J Dai, Q TI High-resolution imaging of liquid structures: Wetting and capillary phenomena at the nanometer scale SO MRS BULLETIN LA English DT Article ID FORCE MICROSCOPY; THIN-FILMS; WATER C1 FUDAN UNIV,DEPT PHYSIOL & BIOPHYS,SHANGHAI,PEOPLES R CHINA. SHANGHAI INST NUCL RES,SHANGHAI,PEOPLES R CHINA. IBM CORP,STORAGE SYST DIV,SAN JOSE,CA. RP Salmeron, M (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV SCI MAT,BERKELEY,CA 94720, USA. NR 18 TC 35 Z9 35 U1 2 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD AUG PY 1997 VL 22 IS 8 BP 36 EP 41 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XR891 UT WOS:A1997XR89100024 ER PT J AU Dahmen, U Johnson, E Xiao, SQ Johansen, A AF Dahmen, U Johnson, E Xiao, SQ Johansen, A TI High-resolution-electron-microscopy investigation of nanosize inclusions SO MRS BULLETIN LA English DT Article ID EQUILIBRIUM SHAPE; GRAIN-BOUNDARIES; AL; PB; PARTICLES; SOLIDIFICATION; ALUMINUM; NUCLEI C1 UNIV COPENHAGEN,NIELS BOHR INST,ORSTED LAB,DK-1168 COPENHAGEN,DENMARK. RP Dahmen, U (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CHEM BIODYNAM LAB,BERKELEY,CA 94720, USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD AUG PY 1997 VL 22 IS 8 BP 49 EP 52 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XR891 UT WOS:A1997XR89100026 ER PT J AU Chisholm, MF Pennycook, SJ AF Chisholm, MF Pennycook, SJ TI Z-contrast imaging of grain-boundary core structures in semiconductors SO MRS BULLETIN LA English DT Article ID GERMANIUM; CRYSTALS; DEFECTS; SI RP Chisholm, MF (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,MS 6030,POB 2008,OAK RIDGE,TN 37831, USA. NR 23 TC 14 Z9 14 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD AUG PY 1997 VL 22 IS 8 BP 53 EP 57 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XR891 UT WOS:A1997XR89100027 ER PT J AU KirschVolders, M Elhajouji, A Cundari, E VanHummelen, P AF KirschVolders, M Elhajouji, A Cundari, E VanHummelen, P TI The in vitro micronucleus test: A multi-endpoint assay to detect simultaneously mitotic delay, apoptosis, chromosome breakage, chromosome loss and non-disjunction SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article ID IN-SITU HYBRIDIZATION; MOUSE BONE-MARROW; RADIATION-INDUCED MICRONUCLEI; BLOCKED HUMAN-LYMPHOCYTES; WILD-TYPE P53; FLOW-CYTOMETRY; INSITU HYBRIDIZATION; DNA PROBES; CELL-DEATH; ANTIKINETOCHORE ANTIBODY AB Genotoxicity testing aims to detect a large range of genetic damage endpoints and evaluate such results in context of cell survival. The cytokinesis block micronucleus test offers the advantage to provide simultaneously information on both cell cycle progression and chromosome/genome mutations. Indeed, 1. frequencies of cytokinesis-blocked binucleated cells (and polynucleated) are good estimators of the mitotic rate; 2. frequencies of apoptotic figures in mononucleated and binucleated cells provide a measure for cell death before or after cell division; 3. combination of fluorescence in situ hybridization (FISH) for centromere/telomeres and micronucleus scoring allows discrimination between clastogenic and aneugenic events; 4. detection of FISH signals for chromosome specific sequences in both macronuclei and micronuclei, discriminates between aneuploidy due to chromosome non-disjunction or to chromosome loss. The cytokinesis block in vitro micronucleus test is thus a cytogenetic multi-test providing mechanistic information with a simple, rapid, objective, microscopical analysis. C1 LAWRENCE LIVERMORE NATL LAB, BIOL & BIOTECHNOL RES PROGRAM, LIVERMORE, CA USA. RP KirschVolders, M (reprint author), FREE UNIV BRUSSELS, LAB ANTHROPOGENET, PLEINLAAN 2, B-1050 BRUSSELS, BELGIUM. NR 79 TC 197 Z9 203 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5718 J9 MUTAT RES-GEN TOX EN JI Mutat. Res. Genet. Toxicol. Environ. Mutagen. PD AUG 1 PY 1997 VL 392 IS 1-2 BP 19 EP 30 DI 10.1016/S0165-1218(97)00042-6 PG 12 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA XQ834 UT WOS:A1997XQ83400004 PM 9269328 ER PT J AU Gustavsson, P Willig, TN vanHaeringen, A Tchernia, G Dianzani, I Donner, M Elinder, G Henter, JI Nilsson, PG Gordon, L Skeppner, G vantVeerKorthof, L Kreuger, A Dahl, N AF Gustavsson, P Willig, TN vanHaeringen, A Tchernia, G Dianzani, I Donner, M Elinder, G Henter, JI Nilsson, PG Gordon, L Skeppner, G vantVeerKorthof, L Kreuger, A Dahl, N TI Diamond-Blackfan anaemia: Genetic homogeneity for a gene on chromosome 19q13 restricted to 1.8 Mb SO NATURE GENETICS LA English DT Article ID CONGENITAL HYPOPLASTIC-ANEMIA; HYBRIDIZATION; MUTATIONS AB Diamond-Blackfan anaemia (DEA; MIM#205900) is a rare disorder manifested as a pure red-cell aplasia in the neonatal period or in infancy(1-3). The clinical hallmark of DBA is a selective decrease in erythroid precursors and anaemia. Other lineages are usually normal and the peripheral white blood cell count is normal. In approximately one-third of cases, the disease is associated with a wide variety of congenital anomalies and malformations(3-7). Most cases are sporadic, but 10-20% of them follow a recessive or a dominant inheritance pattern(5). A female with DBA and a chromosomal translocation involving chromosome 19q was recently identified(8). We undertook a linkage analysis with chromosome 19 markers in multiplex DBA families of Swedish, French, Dutch, Arabic and Italian origin. Significant linkage to chromosome 19q13 was established for dominant and recessive inherited DBA with a peak rod score at D19S197 (Z(max)=7.08, theta=0.00). Within this region, a submicroscopic de novo deletion of 3.3 Mb was identified in a patient with DBA. The deletion coincides with the translocation break-point and, together with key recombinations, restricts the DBA gene to a 1.8-Mb region. The results suggest that, despite its clinical heterogeneity, DBA is genetically homogeneous for a gene in 19q13. C1 UNIV UPPSALA,CHILDRENS HOSP,DEPT CLIN GENET,S-75185 UPPSALA,SWEDEN. HOP BICETRE,DEPT HEMATOL,LE KREMLIN BICETR,FRANCE. HOP BICETRE,DEPT PAEDIAT,LE KREMLIN BICETR,FRANCE. LEIDEN UNIV HOSP,DEPT CLIN GENET,LEIDEN,NETHERLANDS. UNIV TURIN,DEPT PAEDIAT,I-10124 TURIN,ITALY. UNIV TURIN,DEPT GENET,I-10124 TURIN,ITALY. UNIV LUND HOSP,ASTRID LINDGREN CHILD CTR,LUND,SWEDEN. UNIV LUND HOSP,DEPT MED,LUND,SWEDEN. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. OREBRO REG HOSP,DEPT PAEDIAT,OREBRO,SWEDEN. UNIV UPPSALA,CHILDRENS HOSP,DEPT PAEDIAT,S-75185 UPPSALA,SWEDEN. NR 23 TC 65 Z9 65 U1 0 U2 1 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1061-4036 J9 NAT GENET JI Nature Genet. PD AUG PY 1997 VL 16 IS 4 BP 368 EP 371 DI 10.1038/ng0897-368 PG 4 WC Genetics & Heredity SC Genetics & Heredity GA XM909 UT WOS:A1997XM90900019 PM 9241274 ER PT J AU Huang, L Weng, XW Hofer, F Martin, GS Kim, SH AF Huang, L Weng, XW Hofer, F Martin, GS Kim, SH TI Three-dimensional structure of the Ras-interacting domain of RalGDS SO NATURE STRUCTURAL BIOLOGY LA English DT Letter ID NUCLEOTIDE DISSOCIATION STIMULATOR; SIGNAL-TRANSDUCTION; PLASMA-MEMBRANE; PROTEIN; ACTIVATION; IDENTIFICATION; TRANSFORMATION; RESOLUTION; COMPLEX; GTPASE AB The Ras-interacting domains of the the protein-kinase Raf and the Ral guanine nucleotide dissociation stimulator, RalGDS, lack extensive sequence similarity, but their overall three-dimensional structures are very similar to each other. Mutational analysis indicated that three residues in the RalGDS domain are critical for its interaction with Ras. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DEPT CHEM & STRUCT BIOL,DIV EO,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MOL & CELL BIOL,BERKELEY,CA 94720. NR 46 TC 65 Z9 68 U1 0 U2 1 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD AUG PY 1997 VL 4 IS 8 BP 609 EP 615 DI 10.1038/nsb0897-609 PG 7 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA XP316 UT WOS:A1997XP31600007 PM 9253406 ER PT J AU Lee, YH Olson, TW Ogata, CM Levitt, DG Banaszak, LJ Lange, AJ AF Lee, YH Olson, TW Ogata, CM Levitt, DG Banaszak, LJ Lange, AJ TI Crystal structure of a trapped phosphoenzyme during a catalytic reaction SO NATURE STRUCTURAL BIOLOGY LA English DT Letter ID HEPATIC 6-PHOSPHOFRUCTO-2-KINASE FRUCTOSE-2,6-BISPHOSPHATASE; RAT-LIVER FRUCTOSE-2,6-BISPHOSPHATASE; 6-PHOSPHOFRUCTO-2-KINASE/FRUCTOSE-2,6-BISPHOSPHATASE; GLUCONEOGENESIS; GLYCOLYSIS; BINDING; DOMAIN AB The crystal structure of the fructose-2,6-bisphosphatase domain trapped during the reaction reveal a phosphorylated His 258, and a water molecule immobilized by the product, fructose-6-phosphate. The geometry suggests that the dephosphorylation step requires prior removal of the product for an 'associative in-line' phosphoryl transfer to the catalytic water. C1 UNIV MINNESOTA,DEPT BIOCHEM,MINNEAPOLIS,MN 55455. BROOKHAVEN NATL LAB,HOWARD HUGHES MED INST,UPTON,NY 11973. UNIV MINNESOTA,DEPT PHYSIOL,MINNEAPOLIS,MN 55455. NR 24 TC 29 Z9 30 U1 0 U2 2 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD AUG PY 1997 VL 4 IS 8 BP 615 EP 618 DI 10.1038/nsb0897-615 PG 4 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA XP316 UT WOS:A1997XP31600008 PM 9253407 ER PT J AU Feller, MB Butts, DA Aaron, HL Rokhsar, DS Shatz, CJ AF Feller, MB Butts, DA Aaron, HL Rokhsar, DS Shatz, CJ TI Dynamic processes shape spatiotemporal properties of retinal waves SO NEURON LA English DT Article ID CHOLINERGIC AMACRINE CELLS; DEVELOPING MAMMALIAN RETINA; RABBIT RETINA; GANGLION-CELLS; SYNAPTIC ORGANIZATION; OLFACTORY NETWORK; BURSTING ACTIVITY; NEURONS; CAT; ACETYLCHOLINE AB In the developing mammalian retina, spontaneous waves of action potentials are present in the ganglion cell layer weeks before vision. These waves are known to be generated by a synaptically connected network of amacrine cells and retinal ganglion cells, and exhibit complex spatiotemporal patterns, characterized by shifting domains of coactivation. Here, we present a novel dynamical model consisting of two coupled populations of cells that quantitatively reproduces the experimentally observed domain sizes, interwave intervals, and wavefront velocity profiles. Model and experiment together show that the highly correlated activity generated by retinal waves can be explained by a combination of random spontaneous activation of cells and the past history of local retinal activity. C1 UNIV CALIF BERKELEY,DEPT MOL & CELL BIOL,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP Feller, MB (reprint author), UNIV CALIF BERKELEY,HOWARD HUGHES MED INST,BERKELEY,CA 94720, USA. RI Butts, Daniel/B-8346-2008 OI Butts, Daniel/0000-0002-0158-5317 FU NIMH NIH HHS [MH 48108] NR 57 TC 115 Z9 118 U1 0 U2 1 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 SN 0896-6273 J9 NEURON JI Neuron PD AUG PY 1997 VL 19 IS 2 BP 293 EP 306 DI 10.1016/S0896-6273(00)80940-X PG 14 WC Neurosciences SC Neurosciences & Neurology GA XU146 UT WOS:A1997XU14600009 PM 9292720 ER PT J AU Gorelenkov, NN Budny, RV Duong, HH Fisher, RK Medley, SS Petrov, MP Redi, MH AF Gorelenkov, NN Budny, RV Duong, HH Fisher, RK Medley, SS Petrov, MP Redi, MH TI Modelling of alpha particle slowing down, confinement and redistribution by sawteeth in TFTR using the FPPT code SO NUCLEAR FUSION LA English DT Article ID SAWTOOTH OSCILLATIONS; TOKAMAK; TRITONS; SIMULATIONS; OPERATION; TRANSPORT; CRASHES; REACTOR; IONS; CORE AB Results from recent deuterium-tritium (DT) experiments on TFTR to measure the energy spectra and radial profiles of well trapped confined alpha particle distributions using the pellet charge exchange (PCX) diagnostic in quiescent plasmas are compared with a numerical modelling using the Fokker-Planck post-TRANSP (FPPT) processor code and show a classical slowing down behaviour of the alphas (Fisher, R.K., et al., Phys. Rev. Lett. 75 (1995) 846). However, in the presence of sawtooth oscillations PCX experimental data indicate a significant broadening of the trapped alpha radial distributions (Petrov, M.P., et al., Nucl. Fusion 35 (1995) 1437). Conventional models consistent with measured sawtooth effects on passing particles db not provide satisfactory simulations of the trapped particle mixing measured by the PCX diagnostic. A mechanism is proposed for fast particle mixing during the sawtooth crash to explain the trapped alpha particle radial profile broadening after the crash. The model is based on the fast particle orbit averaged toroidal drift in a perturbed helical electric field with an adjustable absolute value (similar to that in Kolesnichenko, Ya.I., et al., Nucl. Fusion 36 (1996) 159). Such a drift of the fast particles results in a change of their energy and a redistribution in phase space. To show the sensitivity of trapped particles to sawteeth, the redistribution in toroidal momentum P-phi (or in minor radius) was calculated in two ways. The first is based on the assumption that P-phi redistribution is stochastic with a large diffusion coefficient and was taken to be flat. The second way is to apply Kolesnichenko's inversion formula (Kolesnichenko, Ya.I., et al., Nucl. Fusion 32 (1992) 449). Both methods are compared with PCX data. The distribution function in a pre-sawtooth plasma and its evolution in a post-sawtooth crash plasma are simulated using the FPPT code. It is shown that FPPT calculated alpha particle distributions are consistent with TRANSP Monte Carlo calculations. Comparison of FPPT results with PCX measurements shows good agreement for both sawtooth-free and sawtoothing plasmas. RP Gorelenkov, NN (reprint author), PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. NR 33 TC 25 Z9 25 U1 1 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD AUG PY 1997 VL 37 IS 8 BP 1053 EP 1066 DI 10.1088/0029-5515/37/8/I02 PG 14 WC Physics, Fluids & Plasmas SC Physics GA YF269 UT WOS:A1997YF26900002 ER PT J AU Garzotti, L Pegourie, B Geraud, A Frigione, D Baylor, LR AF Garzotti, L Pegourie, B Geraud, A Frigione, D Baylor, LR TI Neutral gas and plasma shielding scaling law for pellet ablation in Maxwellian plasmas SO NUCLEAR FUSION LA English DT Article ID HYDROGEN PELLET; CLOUD; MODEL; TOKAMAK; FLOW AB Pellet penetrations are generally well reproduced by the neutral gas shielding (NGS) scaling law when neutral gas and plasma shielding (NGPS) models are less successful, although their description of the ablation physics is much more realistic. The solution of this apparent contradiction is to be found in the structure of the NGPS models. Indeed, since they are generally not fully self-consistent, several choices are possible in the description of the elementary shielding processes. The problem thus reduces to finding a set of compatible assumptions defining an NGPS model that can fit the experimental measurements on a database as large as possible. The model presented here reproduces the penetrations of approximate to 120 pellets from 5 different machines: Tore Supra, JET, FTU, T-10 and RTP. An NGPS scaling law has been constructed for the ablation rate that exhibits dependences on n(e), T-e and r(p) close to those of the NGS model, in addition to weak dependences on the magnetic field and tokamak major radius. For reactor grade plasmas, the penetrations calculated by the NGPS model are approximate to 15% smaller than the NGS predictions. C1 ENEA,ROME,ITALY. OAK RIDGE NATL LAB,OAK RIDGE,TN. RP Garzotti, L (reprint author), CTR ETUD CADARACHE,DEPT RECH FUS CONTROLEE,ST PAUL DURANCE,FRANCE. NR 25 TC 33 Z9 35 U1 0 U2 4 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD AUG PY 1997 VL 37 IS 8 BP 1167 EP 1175 DI 10.1088/0029-5515/37/8/I11 PG 9 WC Physics, Fluids & Plasmas SC Physics GA YF269 UT WOS:A1997YF26900011 ER PT J AU McGregor, DS Hermon, H AF McGregor, DS Hermon, H TI Room-temperature compound semiconductor radiation detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 4th International Workshop on GaAs Detectors and Related Compounds CY JUN 03-06, 1996 CL KINLOCHARD, SCOTLAND SP Brit Nucl Fuels Ltd, MCP Wafer Technol, METOREX Oy, REGAM Med Syst, Justerini & Books ID GAMMA-RAY DETECTORS; GAAS PARTICLE DETECTORS; IODIDE X-RAY; CHARGE COLLECTION EFFICIENCY; INP-FE PHOTOCONDUCTORS; VERTICAL BRIDGMAN GROWTH; SOLID-STATE DETECTORS; LIQUID-PHASE EPITAXY; I-N CDTE; MERCURIC IODIDE AB A summary is presented of the present status of several compound semiconductor radiation detectors, including detectors fabricated from GaAs, HgI2, CdTe, Cd1-xZnxTe and PbI2. C1 SANDIA NATL LABS, MS 9671, LIVERMORE, CA 94551 USA. RP UNIV MICHIGAN, DEPT NUCL ENGN, ANN ARBOR, MI 48109 USA. NR 348 TC 152 Z9 153 U1 4 U2 28 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 AUG 1 PY 1997 VL 395 IS 1 BP 101 EP 124 DI 10.1016/S0168-9002(97)00620-7 PG 24 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XV147 UT WOS:A1997XV14700020 ER PT J AU Dadachova, E Mirzadeh, S AF Dadachova, E Mirzadeh, S TI The role of tin in the direct labelling of proteins with rhenium-188 SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article ID MONOCLONAL-ANTIBODIES; TC-99M; RE-188 AB In the process of direct labelling of proteins with Re-188, the influence of Sn(II) in the concentration range of 5 x 10(-4)-1 mg/mL of protein was studied using Sn-117m radiolabel in the presence of two transchelation buffers-sodium gluconate and sodium citrate. It was shown that Sn(II) readily binds to the thiol groups on the protein, and the fraction of Sn bound to the protein was 5 to 10 times higher in citrate than in gluconate for all Sn(II) concentrations studied. At saturation point of similar to 1 mu g (10(-8) M) Sn/mg protein in gluconate, 16% of the protein thiol groups were bound to Sn, and at similar to 2.4 mu g (2 x 10(-8) M) in citrate, 32% of thiols were bound to Sn. A mechanism was proposed for the involvement of Sn(II) in labelling of pre-reduced proteins with Re-188 via formation of protein-tin-Re-188(V) reaction intermediate. It was further shown that the amount of Sn(II) in reaction mixture must exceed a certain level in order to achieve high labelling yields, and this level of Sn(II) was found to be different for citrate and gluconate buffers. C1 OAK RIDGE NATL LAB,NUCL MED GRP,OAK RIDGE,TN 37831. RP Dadachova, E (reprint author), AUSTRALIAN NUCL SCI & TECHNOL ORG,PMB 1,MENAI,NSW 2234,AUSTRALIA. RI Dadachova, Ekaterina/I-7838-2013 NR 19 TC 23 Z9 27 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD AUG PY 1997 VL 24 IS 6 BP 605 EP 608 DI 10.1016/S0969-8051(97)00079-6 PG 4 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA XU264 UT WOS:A1997XU26400018 PM 9316092 ER PT J AU Cini, M Balzarotti, A Gammel, JT Bishop, AR AF Cini, M Balzarotti, A Gammel, JT Bishop, AR TI Configuration interaction and pairing in superconducting cuprates SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA D-CONDENSED MATTER ATOMIC MOLECULAR AND CHEMICAL PHYSICS FLUIDS PLASMAS BIOPHYSICS LA English DT Article; Proceedings Paper CT VIII Congress of SATT CY OCT 01-04, 1996 CL COMO, ITALY SP SATT ID HIGH-TEMPERATURE SUPERCONDUCTORS; ELECTRON-ENERGY-LOSS; SYMMETRY AB We propose a quantum-mechanical effect specific of the symmetry of the Cu-O plane of cuprate superconductors. The mechanism considers hole pairs in single-particle degenerate states which, because of the configuration interaction, form singlet states with zero on-site repulsion (W = 0 pairs). In the many-body problem the effective interaction due to the spin exchange with the holes of b(1) symmetry is attractive. The exact diagonalization of the extended Hubbard Hamiltonian with 4 holes using well-established parameters for several clusters shows that the ground state has B-1(2)(xy) symmetry and that binding energies are of the order of 10 meV. Unlike other electronic mechanisms proposed so far, this effect is due to the symmetry of the system and does not rely on off-site inter actions; when the symmetry is broken the repulsion wins. Besides the correct symmetry of the pair, we obtain good agreement with experiment for the binding energies and the singlet-triplet energy separation of the quasiparticles. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Cini, M (reprint author), UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,INFM,VIA RIC SCI 1,I-00133 ROME,ITALY. NR 13 TC 7 Z9 7 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 0392-6737 J9 NUOVO CIMENTO D JI Nuovo Cimento Soc. Ital. Fis. D-Condens. Matter At. Mol. Chem. Phys. Fluids Plasmas Biophys. PD AUG-SEP PY 1997 VL 19 IS 8-9 BP 1329 EP 1334 PG 6 WC Physics, Multidisciplinary SC Physics GA YE563 UT WOS:A1997YE56300046 ER PT J AU Hanrahan, RJ Butt, DP AF Hanrahan, RJ Butt, DP TI The effects of nitrogen on the kinetics and mechanisms of oxidation of titanium-tantalum alloys SO OXIDATION OF METALS LA English DT Article DE titanium; tantalum; nitrogen effect; oxidation kinetics AB The oxidation kinetics of Titanium alloys containing nominally 5, 40, and 60 weight percent Ta were measured for 16 hr in nitrogen-20% oxygen. In all three alloys at each temperature tested oxidation rates in the nitrogen-oxygen mixture were significantly lower than those previously measured in argon-20% oxygen or pure oxygen. Using X-ray diffraction and electron microprobe a nitrogen rich layer was identified in the scale near the scale/metal interface. This layer apparently acts as an oxygen-diffusion barrier, as demonstrated by the reduced depth of oxygen penetration in the metal relative to identical specimens oxidized in nitrogen-free atmospheres. RP Hanrahan, RJ (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,MAT CORROS & ENVIRONM EFFECTS LAB,LOS ALAMOS,NM 87545, USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 7 TC 16 Z9 17 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0030-770X J9 OXID MET JI Oxid. Met. PD AUG PY 1997 VL 48 IS 1-2 BP 41 EP 58 DI 10.1007/BF01675261 PG 18 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA XR768 UT WOS:A1997XR76800002 ER PT J AU Wilde, P QuinbyHunt, MS AF Wilde, P QuinbyHunt, MS TI Collisions with ice volatile objects: Geological implications - A qualitative treatment SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article; Proceedings Paper CT Meeting of the International-Geological-Correlation-Programme (IGCP) Project 293 Geochemical Event Markers in the Phanerozoic CY 1994 CL ERLANGEN, GERMANY SP Int Geol Correlat Programme DE bolide; volatiles; impacts; geochemical event markers ID CRETACEOUS-TERTIARY BOUNDARY; HALLEY DUST PARTICLES; COMET HALLEY; STRANGELOVE OCEAN; HYDROGEN-SULFIDE; ISOTOPE EVIDENCE; IMPACT; EXTINCTION; CARBON; BOLIDE AB An aperiodic collision of the Earth with extra-terrestrial ice/volatile bodies is proposed as a mechanism to produce rapid changes in the geologic record. Due to the volatile nature of these bodies, evidence for their impacts, particularly in the ocean, might be subtle and best seen as 'spikes' in the geochemical or fossil record against normal background. Differing effects would result depending on the sire of the major break-up of the object: in the atmosphere, on land, or in the ocean. This paper focuses on the effects of adding material to the seas, oceans, and atmosphere. The treatment is largely qualitative, however mass balance calculations were used to estimate the relative mass needed to affect changes in a variety of reservoirs. Although actual impactors probably have a variable composition, the effects of water-, C-, N-, and S-containing objects are discussed. In the atmosphere, effects could include increased rain acidity, increased levels of nutrients, and enhanced greenhouse warming/cooling. Oceanic effects might include increased oceanic productivity (nitrogen-containing objects). As a result of increased chemical weathering and/or greenhouse effects, increased temperatures coupled with enhanced productivity could result in wider-spread oceanic anoxia or altered calcite/aragonite stability. Possible examples of such impacts from the geologic record and potential biotic effects are given. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720. OFF NAVAL RES,ASIAN OFF,TOKYO,JAPAN. NR 104 TC 11 Z9 11 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD AUG PY 1997 VL 132 IS 1-4 BP 47 EP 63 DI 10.1016/S0031-0182(97)00050-3 PG 17 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA XY805 UT WOS:A1997XY80500004 PM 11541729 ER PT J AU Ulicny, D Hladikova, J Attrep, MJ Cech, S Hradecka, L Svobodova, M AF Ulicny, D Hladikova, J Attrep, MJ Cech, S Hradecka, L Svobodova, M TI Sea-level changes and geochemical anomalies across the Cenomanian-Turonian boundary: Pecinov quarry, Bohemia SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article; Proceedings Paper CT Meeting of the International-Geological-Correlation-Programme (IGCP) Project 293 Geochemical Event Markers in the Phanerozoic CY 1994 CL ERLANGEN, GERMANY SP Int Geol Correlat Programme DE eustasy; Oceanic Anoxic Event; sequence stratigraphy; Cretaceous; stable isotopes ID WESTERN INTERIOR; CARBON-ISOTOPE; PARIS BASIN; EXTINCTION INTERVAL; MASS EXTINCTIONS; CRETACEOUS BASIN; ORGANIC-CARBON; UNITED-STATES; OXYGEN; STRATIGRAPHY AB Relationships between geochemical anomalies, sea-level change and other events were studied in the Cenomanian-Turonian boundary interval in the Pecinov quarry in southwestern part of the Bohemian Cretaceous Basin (Czech Republic). A major 3rd-order sea-level rise at the base of the late Cenomanian M. geslinianum Zone was followed by deposition of organic-enriched mudstones in a succession of parasequences, deposited in response to high-frequency (4th-order) sea-level fluctuations and recording a stepwise decrease in bottom oxygenation towards intensely dysaerobic conditions. A complex delta(13)C excursion occurs in total organic matter of the late Cenomanian deposits. A sequence boundary of latest Cenomanian age in the Pecinov section is correlated to a global sea-level fall during the N. juddii Zone. A renewed sea-level rise occurred during the early Turonian W. coioradoense Zone and reached maximum flooding during the M. nodosoides Zone. During the early Turonian, bottom waters were generally aerobic, and the positive delta(13)C excursion waned early in the W. coloradoense Zone. The magnitude of the delta(13)C excursion: more than 4 parts per thousand, is approximately the same as in North America and Not-them Africa, confirming that it was controlled by a global paleoceanographic mechanism. The absence of anoxia and a delta(13)C anomaly during the peak flooding of early Turonian age suggests that widespread deposition of organic-enriched deposits, as well as the positive shift in delta(13)C generally did not depend on the absolute elevation of sea level but, rather, on the area of newly flooded land during transgression. Abrupt, small-scale shifts in delta(13)C towards higher values coincide with the flooding surfaces of parasequences and may reflect either regional changes in the proportion of marine and terrestrial organic matter or rapid global changes in isotopic composition of marine organic matter related to high-frequency sea-level changes, Abundances of Ir, Sc, Cr, V and other elements previously reported as forming anomalous concentrations in the boundary interval showed no enrichment in the Bohemian section. This is most probably due to the large distance of the depositional site from the presumed volcanic source of element-enriched, deep waters in the proto-Caribbean region. Anomalous concentration of Mn at the base of the Turonian deposits was caused by diagenetic incorporation of Mn into siderite. (C) 1997 Elsevier Science B.V. C1 CZECH GEOL SURVEY,PRAGUE 11821 1,CZECH REPUBLIC. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. ACAD SCI CZECH REPUBL,INST GEOL,PRAGUE 16500 6,CZECH REPUBLIC. RP Ulicny, D (reprint author), CHARLES UNIV,DEPT GEOL,ALBERTOV 6,PRAGUE 12843 2,CZECH REPUBLIC. RI Svobodova, Marcela/I-8793-2014; Ulicny, David/H-6412-2014 NR 60 TC 33 Z9 33 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD AUG PY 1997 VL 132 IS 1-4 BP 265 EP 285 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA XY805 UT WOS:A1997XY80500018 ER PT J AU Idasetima, JS Petrovic, JJ AF Idasetima, JS Petrovic, JJ TI Effects of carbon additions on MoSi2 microstructure and properties SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID TEMPERATURE MECHANICAL-PROPERTIES; MOLYBDENUM DISILICIDE; COMPOSITES AB Carbon as a second-phase particulate addition to a MoSi2 matrix has been investigated for possible improved mechanical property effects. MoSi2 with 0, 1, 2 and 4 wt% C was fabricated using hot pressing and containerless hot isostatic pressing at temperatures of 1400, 1600 and 1800 degrees C. These processing conditions showed the formation of an in-situ SiC phase and the ternary Nowotny phase C<1Mo<5Si3, which affected the microstructure and fracture behaviour of the materials. Microindentation techniques were used to evaluate the hardness and fracture toughness of the MoSi2 and C-MoSi2 materials. Increasing the processing temperature increased the hardness due to in-situ SiC formation as a result of carbon reaction with silica, although only modest improvements in fracture toughness were observed. RP Idasetima, JS (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,CERAM SCI & TECHNOL GRP,LOS ALAMOS,NM 87545, USA. NR 13 TC 4 Z9 4 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1997 VL 76 IS 2 BP 271 EP 287 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA XP232 UT WOS:A1997XP23200001 ER PT J AU Ballesteros, C Chen, Y Chen, Y Gonzalez, R Kokta, MR Zong, XF AF Ballesteros, C Chen, Y Chen, Y Gonzalez, R Kokta, MR Zong, XF TI Precipitates in thermochemically reduced nickel-doped sapphire SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID MGO CRYSTALS; DIELECTRIC-BREAKDOWN; ELECTRON-MICROSCOPE; HIGH-TEMPERATURES; PHASE FORMATION; OPERATION; GROWTH; LASERS; NI-2+; MGF2 AB Nickel-doped Al2O3 (sapphire) crystals have been studied using optical absorption and transmission electron microscopy. After reduction at elevated temperatures in a hydrogen atmosphere, these crystals exhibit a dark colouration. Our results indicate that the colouration is due to Mie scattering from precipitates resulting from the reduction process. Analytical transmission electron microscopy techniques revealed the presence of metallic precipitates and identified them as Al3Ni. The precipitate distribution is very inhomogeneous. C1 FUDAN UNIV,DEPT MAT SCI & ENGN,SHANGHAI 200433,PEOPLES R CHINA. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNION CARBIDE CORP,WASHOUGAL,WA 98671. DEPT ENERGY,DIV MAT SCI,DAMASCUS,MD 20872. RP Ballesteros, C (reprint author), UNIV CARLOS III MADRID,DEPT FIS,C BUTARQUE 15,LEGANES 28911,SPAIN. OI BALLESTEROS, CARMEN INES/0000-0002-8983-4751 NR 30 TC 5 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1997 VL 76 IS 2 BP 357 EP 365 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA XP232 UT WOS:A1997XP23200007 ER PT J AU Bennett, K Wenk, HR Durham, WB Stern, LA Kirby, SH AF Bennett, K Wenk, HR Durham, WB Stern, LA Kirby, SH TI Preferred crystallographic orientation in the ice I->II transformation and the flow of ice II SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID SELF-CONSISTENT THEORY; TEXTURE DEVELOPMENT; PLASTIC-DEFORMATION; STRAIN; ROCKS AB The preferred crystallographic orientation developed during the ice I --> II transformation and during the plastic flow of ice II was measured in polycrystalline deuterium oxide (D2O) specimens using low-temperature neutron diffraction. Samples partially transformed from ice I to II under a non-hydrostatic stress developed a preferred crystallographic orientation in the ice II. Samples of pure ice II transformed from ice I under a hydrostatic stress and then when compressed axially, developed a strong preferred orientation of compression axes parallel to (10 (1) over bar 0). A match to the observed preferred orientation using the viscoplastic self-consistent theory was obtained only when (10 (1) over bar 0) [0001] was taken as the predominant slip system in ice II. C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. US GEOL SURVEY,MENLO PK,CA 94025. NR 47 TC 15 Z9 15 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1997 VL 76 IS 2 BP 413 EP 435 PG 23 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA XP232 UT WOS:A1997XP23200010 ER PT J AU Wu, LJ Zhu, YM AF Wu, LJ Zhu, YM TI Transformation twinning in carbon-doped PrCo2 magnetic crystals SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID UPSET PRCO5-TYPE MAGNETS; PERMANENT-MAGNETS AB A rhombohedral PrCo2Cx (x = 0.05-0.25) phase (space group, R (3) over bar m) was observed and characterized in an original cubic PrCo2 hard magnet (space group, Fd (3) over bar m) after adding carbon. The rhombohedral crystal is heavily twinned along the {110} and {211} planes. The twinning mechanism was explored by analysing the reduction in crystal symmetry due to the cubic-to-rhombohedral phase transformation. The origin of the twinning and the formation of four twin variants were attributed to the insertion of carbon interstitials into Co-4 tetrahedra along the (3) over bar axis in the rhombohedral lattice, which corresponds to one of the four equivalent [111] axes of the parent cubic lattice. RP Wu, LJ (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 14 TC 5 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1997 VL 76 IS 2 BP 481 EP 492 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA XP232 UT WOS:A1997XP23200014 ER PT J AU Kresin, VZ Wolf, SA AF Kresin, VZ Wolf, SA TI Jahn-Teller dynamics and properties of the manganites SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID RESISTIVITY AB The ferromagnetic transition temperature and the oxygen isotope effect in the doped manganites are evaluated using a model based on the dynamic Jahn-Teller effect on the bridging oxygen ion (the ion between Mn3+ and Mn4+). The diabatic representation is used to estimate the hopping time of the extra electron in the double exchange model. The transition temperature depends strongly on the Franck-Condon factor and, therefore, on the oxygen mass. C1 USN,RES LAB,WASHINGTON,DC 20375. RP Kresin, VZ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Wolf, Stuart/A-7513-2009 NR 22 TC 16 Z9 16 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD AUG PY 1997 VL 76 IS 2 BP 241 EP 245 DI 10.1080/01418639708241088 PG 5 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA XP231 UT WOS:A1997XP23100007 ER PT J AU Fisher, WG Partridge, WP Dees, C Wachter, EA AF Fisher, WG Partridge, WP Dees, C Wachter, EA TI Simultaneous two-photon activation of type-I photodynamic therapy agents SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID 2-PHOTON EXCITED FLUORESCENCE; 2ND HARMONIC DETECTION; LASER; ABSORPTION; PSORALENS; PHOTOCHEMISTRY; HEMATOPORPHYRIN; SPECTROSCOPY; PHEOPHORBIDE; DEPENDENCE AB The excitation and emission properties of several psoralen derivatives are compared using conventional single-photon excitation and simultaneous two-photon excitation (TPE), Two-photon excitation is effected using the output of a mode-locked titanium:sapphire laser, the near infrared output of which is used to promote nonresonant TPE directly. Specifically, the excitation spectra and excited-state properties of 8-methoxypsoralen and 4'-aminomethyl-4,5,8-trimethylpsoralen are shown to be equivalent using both modes of excitation. Further, in vitro feasibility of two-photon photodynamic therapy (PDT) is demonstrated using Salmonella typhimurium. Two-photon excitation may be beneficial in the practice of PDT because it would allow replacement of visible or UV excitation light with highly penetrating, nondamaging near infrared light and could provide a means for improving localization of therapy, Comparison of possible laser excitation sources for PDT reveals the titanium: sapphire laser to be exceptionally well suited for nonlinear excitation of PDT agents in biological systems due to its extremely short pulse width and high repetition rate that together provide efficient PDT activation and greatly reduced potential for biological damage. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 58 TC 190 Z9 190 U1 1 U2 33 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD AUG PY 1997 VL 66 IS 2 BP 141 EP 155 DI 10.1111/j.1751-1097.1997.tb08636.x PG 15 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA XX489 UT WOS:A1997XX48900006 PM 9277135 ER PT J AU Hennink, SC AF Hennink, SC TI European photonics manufacturers predict key laser applications SO PHOTONICS SPECTRA LA English DT Editorial Material RP Hennink, SC (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAURIN PUBL CO INC PI PITTSFIELD PA BERKSHIRE COMMON PO BOX 1146, PITTSFIELD, MA 01202 SN 0731-1230 J9 PHOTON SPECTRA JI Photon. Spect. PD AUG PY 1997 VL 31 IS 8 BP 70 EP 71 PG 2 WC Optics SC Optics GA XP706 UT WOS:A1997XP70600033 ER PT J AU Uwatoko, Y Mori, N Oomi, G Thompson, JD AF Uwatoko, Y Mori, N Oomi, G Thompson, JD TI Effect of pressure on the Kondo compound CeRhSb SO PHYSICA B LA English DT Article; Proceedings Paper CT International Workshop on Transition Metals and Compounds under Multiextreme Conditions CY SEP 18-20, 1996 CL KUMAMOTO UNIV, KUMAMOTO, JAPAN HO KUMAMOTO UNIV DE CeRhSb; Kondo compound; high pressure ID GAP AB CeRhSb crystallizes in the orthorhombic epsilon-TiNiSi-type structure. It has been shown that CeRhSb is a semiconductor type valence fluctuating compound such as Ce3Pt4Bi3. In the present work we measured the electrical resistivity and magnetoresistance of CeRhSb in the ranges, pressure P, 0 less than or equal to P less than or equal to 8 GPa, temperature T, 2.0 K less than or equal to T less than or equal to 300 K, and magnetic field H, 0 less than or equal to H less than or equal to 5 T. At 1 bar, rho(T) of CeRhSb shows a minimum (T-min) at 7.8 K, which may reflects opening of an energy gap. T-min increases with pressure and has a broad maximum centered near 4 GPa. The pressure dependence of T-min indicates that the gap disappears at pressures between 7 and 8 GPa. The magnetoresistance below 5 T is large and T positive under pressure up to 2.3 GPa. C1 UNIV TOKYO,INST SOLID STATE PHYS,TOKYO 106,JAPAN. KUMAMOTO UNIV,FAC ENGN,KUMAMOTO 860,JAPAN. UNIV CALIF LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. RP Uwatoko, Y (reprint author), SAITAMA UNIV,FAC SCI,URAWA,SAITAMA 338,JAPAN. NR 8 TC 7 Z9 7 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD AUG PY 1997 VL 239 IS 1-2 BP 95 EP 100 DI 10.1016/S0921-4526(97)83245-0 PG 6 WC Physics, Condensed Matter SC Physics GA XV609 UT WOS:A1997XV60900024 ER PT J AU Ishii, T Oomi, G Uwatoko, Y Thompson, JD Madru, D Shero, JL Fisk, Z AF Ishii, T Oomi, G Uwatoko, Y Thompson, JD Madru, D Shero, JL Fisk, Z TI Thermal expansion of CeRhSb under high pressure SO PHYSICA B LA English DT Article; Proceedings Paper CT International Workshop on Transition Metals and Compounds under Multiextreme Conditions CY SEP 18-20, 1996 CL KUMAMOTO UNIV, KUMAMOTO, JAPAN HO KUMAMOTO UNIV DE CeRhSb; thermal expansion; high pressure ID COMPOUND AB The linear thermal expansion of polycrystalline CeRhSb has been measured in the temperature range 77 K < T < 300 K under hydrostatic pressure up to 2.3 GPa. It is found that the thermal expansion coefficient alpha(T) at ambient pressure shows a maximum around T-max = 140 K and T-max increases with increasing pressure having rate of partial derivative T-max/partial derivative P = + 38.5 K/GPa. This fact shows that the Kondo temperature T-K is increased by applying pressure. C1 KUMAMOTO UNIV,DEPT MECH ENGN & MAT SCI,KUMAMOTO 860,JAPAN. SAITAMA UNIV,DEPT PHYS,URAWA,SAITAMA 338,JAPAN. UNIV CALIF LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. NATL HIGH MAGNET FIELD LAB,TALLAHASSEE,FL 32306. NR 4 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD AUG PY 1997 VL 239 IS 1-2 BP 104 EP 105 DI 10.1016/S0921-4526(97)00387-6 PG 2 WC Physics, Condensed Matter SC Physics GA XV609 UT WOS:A1997XV60900026 ER PT J AU Yamada, K Lee, CH Endoh, Y Shirane, G Birgeneau, RJ Kastner, MA AF Yamada, K Lee, CH Endoh, Y Shirane, G Birgeneau, RJ Kastner, MA TI Low-frequency spin fluctuations in the superconducting La2-xSrxCuO4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID DYNAMICS AB Recent progress in low-energy neutron scattering study on the spatially modulated or so-called incommensurate spin fluctuations is reviewed. Well-defined incommensurate spin fluctuations are observed beyond x approximate to 0.05 and up to the highest Sr-concentration x = 0.25 in the present study. The incommensurability delta(x) is saturated at around 1/8 in the overdoped region and Linearly scaled with the upper Limit of T-c(x) between the underdoped and optimally doped region. A characteristic energy E-* below which the dynamical magnetic susceptibility dramatically diminishes in the superconducting state can be determined to be around 7 meV in the energy spectrum of the spin fluctuations for x = 0.15 and x = 0.18 crystals. The disorder effect induces a low-frequency component of the incommensurate spin fluctuations below E-*. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP Yamada, K (reprint author), TOHOKU UNIV,DEPT PHYS,AOBA KU,SENDAI,MIYAGI 98077,JAPAN. RI Yamada, Kazuyoshi/C-2728-2009 NR 16 TC 33 Z9 33 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 85 EP 88 DI 10.1016/S0921-4534(97)00218-9 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400025 ER PT J AU Jorgensen, JD Chmaissem, O Wagner, JL Jensen, WR Dabrowski, B Hinks, DG Mitchell, JF AF Jorgensen, JD Chmaissem, O Wagner, JL Jensen, WR Dabrowski, B Hinks, DG Mitchell, JF TI Defects that control the properties of Tl- and Hg-based superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID HGBA2CUO4+DELTA; DIFFRACTION AB Defects that affect T-c in Tl2Ba2CuO6+delta and HgBa2CuO4+delta have been characterized by neutron powder diffraction In Tl2Ba2CuO6+delta, the dominant defect is interstitial oxygen between the two Tl-O planes, but Cu substitution on the Tl site also affects properties and there is evidence for a second oxygen defect for compositions in the vicinity of maximum T-c. Zn HgBa2CuO4+delta, there are two competing oxygen defects in the Hg layer. The relative concentrations of these defects switches upon passing from the underdoped region, through the maximum T-c, to the overdoped region. This remarkable behavior could result from a change in the topology of the Fermi surface upon passing through the van Hove singularity. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. UNIV N DAKOTA,DEPT PHYS,GRAND FORKS,ND 58202. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. RP Jorgensen, JD (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 10 TC 30 Z9 30 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 AUG PY 1997 VL 282 BP 97 EP 100 DI 10.1016/S0921-4534(97)00225-6 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400028 ER PT J AU Feenstra, R Matsumoto, T Kawai, T AF Feenstra, R Matsumoto, T Kawai, T TI Scanning tunneling microscopy and spectroscopy study of substitution- and defect-doped films of the infinite layer compound SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID THIN-FILMS; SUPERCONDUCTORS; SURFACE; STATES AB Scanning tunneling microscopy and spectroscopy (STM-STS) has been used to study doping induced changes in the local electronic structure of CuO2 planes at the surface of thin epitaxial films of the infinite layer compound Sr(1-x)A(x)CuO(2), chemically modified via substitutions A (Ca, La) on the Sr site. It is observed that doping produces states within the insulating parent band gap, reflecting contributions from dopants (La) as well as composition dependent defects (Sc vacancies). C1 OSAKA UNIV,INST SCI & IND RES,IBARAKI,OSAKA 567,JAPAN. RP Feenstra, R (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 10 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 105 EP 106 DI 10.1016/S0921-4534(97)00228-1 PN 1 PG 2 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400030 ER PT J AU Shen, ZX AF Shen, ZX TI Recent photoemission data from underdoped Bi2212 single crystals SO PHYSICA C LA English DT Meeting Abstract ID NORMAL-STATE; BI2SR2CACU2O8+DELTA; GAP C1 STANFORD UNIV,STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94305. RP Shen, ZX (reprint author), STANFORD UNIV,DEPT APPL PHYS,STANFORD,CA 94305, USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 123 EP 123 DI 10.1016/S0921-4534(97)00235-9 PN 1 PG 1 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400035 ER PT J AU Endoh, Y Birgeneau, RJ Kastner, MA Lee, YS Shirane, G Wakimoto, S Wells, BO Yamada, K AF Endoh, Y Birgeneau, RJ Kastner, MA Lee, YS Shirane, G Wakimoto, S Wells, BO Yamada, K TI Phase separation, staging and spin fluctuations in La2CuO4+y SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SUPERCONDUCTING LA2-XSRXCUO4; DOPED LA2CUO4 AB Oxygen doped La2CuO4+y single crystals have been successively synthesized and studied their structural, magnetic and superconducting characters. Phase separation due to the existence of the miscibility gap as well as the oxygen staging were detected by systematic neutron diffraction studies. Spin correlations and fluctuations were also studied in details. Spin fluctuations in the oxygen doped La2CuO4+y can be compared with those of the Sr doped crystals and is understood in terms of the general 'hole' doping. C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139. MIT,CTR MAT SCI & ENGN,CAMBRIDGE,MA 02139. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Endoh, Y (reprint author), TOHOKU UNIV,DEPT PHYS,AOBA KU,SENDAI,MIYAGI 98077,JAPAN. RI Yamada, Kazuyoshi/C-2728-2009 NR 15 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 170 EP 173 DI 10.1016/S0921-4534(97)00254-2 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400047 ER PT J AU Takahashi, T Yokoya, T Chainani, A Ding, H Campuzano, JC Kasai, M Tokura, Y AF Takahashi, T Yokoya, T Chainani, A Ding, H Campuzano, JC Kasai, M Tokura, Y TI Angle-resolved photoemission study of Sr2RuO4; An extended van-Hove singularity in non-cuprate superconductor SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB We have performed high-resolution angle-resolved photoemission spectroscopy of a non-cuprate layered superconductor Sr2RuO4 to study the electronic structure near the Fermi level (E-F). The result shows an extended van Hove singularity (vHs) along the Ru-O bonding direction just like the cuprate, regardless of the character of the electronic states at E-F This suggests that the extended vHs is a general electronic structure of a two dimensional correlated d-electron metal. We also have found that the observed Fermi surface topology (one electron-like Fermi surface sheet centered at Gamma point and two hole-like ones centered at X point) is qualitatively different from the calculated Fermi surface topology (two electron-like Fermi sheets centered at Gamma point and one hole-like one centered at X point) in the consequence of the existence of the vHs. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60607. JOINT RES CTR ATOM TECHNOL,TSUKUBA,IBARAKI 305,JAPAN. UNIV TOKYO,DEPT APPL PHYS,TOKYO 113,JAPAN. RP Takahashi, T (reprint author), TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 98077,JAPAN. RI Chainani, Ashish/B-3071-2011; Tohoku, Arpes/A-4890-2010; Takahashi, Takashi/E-5080-2010; Campuzano, Juan Carlos/G-4358-2012; Tokura, Yoshinori/C-7352-2009; YOKOYA, Takayoshi/B-1478-2011; OI Chainani, Ashish/0000-0002-5639-5393; Ding, Hong/0000-0003-4422-9248 NR 10 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 218 EP 221 DI 10.1016/S0921-4534(97)00208-6 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400059 ER PT J AU Aeppli, G Mason, TE Mook, HA Schroeder, A Hayden, SM AF Aeppli, G Mason, TE Mook, HA Schroeder, A Hayden, SM TI Magnetic coherence in the superconducting and normal states of La2-xSrxCuO4 SO PHYSICA C LA English DT Meeting Abstract ID LA1.86SR0.14CUO4; FLUCTUATIONS; EXCITATIONS C1 UNIV TORONTO,TORONTO,ON M5S 1A7,CANADA. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RISO NATL LAB,DK-4000 ROSKILDE,DENMARK. UNIV BRISTOL,BRISTOL BS8 1TL,AVON,ENGLAND. RP Aeppli, G (reprint author), NEC RES INST,4 INDEPENDENCE WAY,PRINCETON,NJ 08540, USA. RI Hayden, Stephen/F-4162-2011; Mason, Thomas/M-5809-2014 OI Hayden, Stephen/0000-0002-3209-027X; Mason, Thomas/0000-0003-1880-3971 NR 9 TC 1 Z9 1 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 AUG PY 1997 VL 282 BP 231 EP 231 DI 10.1016/S0921-4534(97)00221-9 PN 1 PG 1 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400063 ER PT J AU Orenstein, J Bokor, J Budiarto, E Corson, J Mallozzi, R Bozovic, I Eckstein, JN AF Orenstein, J Bokor, J Budiarto, E Corson, J Mallozzi, R Bozovic, I Eckstein, JN TI Nonlinear electrodynamics in cuprate superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID VORTEX DYNAMICS; FLUX MOTION; THIN-FILMS; BI2SR2CACU2O8+DELTA AB We present two types of experiments which probe the high-frequency conductivity of BSCCO films in the presence of large superfluid velocities. In the first the superflow is the static velocity field associated with the vortex lattice. In the second the velocity is dynamic, induced by high-intensity single-cycle electromagnetic pulses. We show that intrinsic pair-breaking in a d-wave superconductor can provide a unified explanation for both effects. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA. VARIAN ASSOCIATES INC,EL GINZTON RES CTR,PALO ALTO,CA 94303. RP Orenstein, J (reprint author), UNIV CALIF BERKELEY,BERKELEY,CA 94720, USA. RI Orenstein, Joseph/I-3451-2015; Bokor, Jeffrey/A-2683-2011 NR 12 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 252 EP 255 DI 10.1016/S0921-4534(97)00236-0 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400069 ER PT J AU Clem, JR Pe, T Benkraouda, M AF Clem, JR Pe, T Benkraouda, M TI The role of 2D pancake vortices in high-temperature superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID COUPLING FORCE; FILMS; LINE; STACK AB To describe vortices in the high-temperature superconductors, a multilayer model consisting of alternating superconducting and nonsuperconducting layers is useful. Superconductivity within the layers is strong, while that between superconducting layers is weak. The Lawrence-Doniach model provides a helpful starting point, in treating the in-plane superconductivity via the Ginzburg-Landau theory and the out-of-plane superconductivity via the Josephson effect. With the help of this model, one may represent a vortex line threading through the layers as a stack of 2D pancake vortices connected by Josephson strings, whose axes are confined within the nonsuperconducting layers. The magnetic fields and currents generated by a single pancake vortex can be calculated analytically in the limit of extreme anisotropy or vanishing Josephson coupling. Here, we review the results of this calculation and discuss how pancake vortices magnetically interact with each other in the absence of Josephson coupling. In this limit, pancake vortices at zero temperature strongly prefer to align themselves perpendicular to the superconducting layers. We review recent results showing that a tilted stack of 2D pancake vortices in an infinite set of Josephson-decoupled superconducting layers is unstable when the angle of tilt is greater than 52 degrees. We also discuss the behavior of pancake vortices in a finite set of N superconducting layers. The magnetic-field and current-density distributions generated throughout the multilayer structure by a single pancake vortex in an arbitrary layer can be calculated and used to examine the stability of tilted stacks of pancake vortices, where the tilt is maintained by application of transport currents in the top or bottom superconducting layers. At a sufficiently high transport current in the top layer, we find that the pancake vortex array in this layer shears off. C1 IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. RP Clem, JR (reprint author), IOWA STATE UNIV,AMES LAB,AMES,IA 50011, USA. NR 13 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 311 EP 314 DI 10.1016/S0921-4534(97)00274-8 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400084 ER PT J AU Doyle, RA Khaykovich, B Konczykowski, M Zeldov, E Morozov, N Majer, D Kes, PH Vinokur, V AF Doyle, RA Khaykovich, B Konczykowski, M Zeldov, E Morozov, N Majer, D Kes, PH Vinokur, V TI Vortex matter phase transitions in Bi2Sr2CaCu2O8 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SINGLE-CRYSTALS; LATTICE; CROSSOVER AB Vortex-lattice phase transitions in Bi2Sr2CaCu2O8 crystals are studied using local magnetization measurements. The vortex matter is found to exhibit at least three distinct phases. A rather ordered quasilattice phase is present at low fields. At elevated temperatures the quasilattice melts (or sublimates) through a first-order phase transition, whereas at lower temperatures a transition to a highly disordered vortex solid occurs at the second magnetization peak. A very low density of columnar defects results in significant pinning of the quasilattice, demonstrating the finite shear modulus of this phase. Local ac measurements reveal that in the presence of columns the pinned quasilattice still melts through a first-order phase transition with an observable step in equilibrium magnetization at elevated temperatures. C1 UNIV CAMBRIDGE, IRC SUPERCONDUCT, CAMBRIDGE CB3 0HE, ENGLAND. ECOLE POLYTECH, SOLIDES IRRADIES LAB, CNRS, URA 1380, F-91128 PALAISEAU, FRANCE. LEIDEN UNIV, NL-2300 RA LEIDEN, NETHERLANDS. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RP Doyle, RA (reprint author), WEIZMANN INST SCI, DEPT CONDENSED MATTER PHYS, IL-76100 REHOVOT, ISRAEL. RI Khaykovich, Boris/A-7376-2012; Zeldov, Eli/K-1546-2012 OI Khaykovich, Boris/0000-0002-9490-2771; Zeldov, Eli/0000-0002-8200-4974 NR 23 TC 6 Z9 6 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 AUG PY 1997 VL 282 BP 323 EP 326 DI 10.1016/S0921-4534(97)00277-3 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400087 ER PT J AU Schilling, A Fisher, RA Phillips, NE Welp, U Kwok, WK Crabtree, GW AF Schilling, A Fisher, RA Phillips, NE Welp, U Kwok, WK Crabtree, GW TI Calorimetric evidence for the occurrence of a first-order transition in the mixed state of untwinned YBa2Cu3O7-delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID LATTICE MELTING TRANSITION; HEAT AB Using high-resolution differential thermal analysis (DTA) we have demonstrated directly, for the first time in a thermal experiment, that the vortex lattice of untwinned YBa(2)Cu3O(7-delta) in the mixed state (for magnetic fields H parallel and perpendicular to the c axis of the crystal) undergoes a first-order phase transition. The phase-transition line H-m(T) in the magnetic phase diagram coincides with the vortex-lattice melting line that had been deduced previously from resistivity and magnetization measurements. The value obtained for the latent ansi, L approximate to 0.5 k(B)T per vortex per superconducting layer for H//c, is consistent with that inferred from magnetization data using the Clapeyron equation, thus proving thermodynamic consistency. The specific heat of the vortex fluid is larger than that of the vortex solid. This specific-heat difference, Delta C/T, and the latent heat L, are independent of both the speed and the direction (up or down in T or H) of the traversal of the phase boundary H-m(T), proving that the transition does not have the characteristics of a glass-like melting transition. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Schilling, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 10 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 327 EP 330 DI 10.1016/S0921-4534(97)00278-5 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400088 ER PT J AU DeWilde, Y Iavarone, M Welp, U Metlushko, V Koshelev, AE Aranson, I Crabtree, GW Gammel, PL Bishop, DJ Canfield, PC AF DeWilde, Y Iavarone, M Welp, U Metlushko, V Koshelev, AE Aranson, I Crabtree, GW Gammel, PL Bishop, DJ Canfield, PC TI The superconducting energy gap and vortex lattice structure in LuNi2B2C SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SCANNING-TUNNELING-MICROSCOPY; SPECTROSCOPY AB We present Scanning Tunneling Microscope (STM) observations of the superconducting energy gap and vortex lattice (VL) structure of the (001) face of a LuNi2B2C single crystal. In zero held, the conductance versus voltage characteristics consistently show a peaked structure that can be fitted with a broadened BCS Like density of states, giving a gap value of 2.2 meV and 2 Delta/kT(c) = 3.2 +/- 0.1, implying weak coupling superconductivity. In applied magnetic fields of 0.375 T and 1.5 T, we make the first STM observation of a square VL, with its unit cell rotated 45 degrees with respect to the crystallographic unit cell. The VL structure is analyzed with Ginzburg-Landau theory, including an additional free energy term with four-fold symmetry arising from the tetragonal crystal structure. The square VL is found to be stable if the four-fold free energy term is large enough to cause the ratio of the in-plane upper critical fields H-c2 (45 degrees)/H-c2 (0) to be less than 0.97. Measurements of the in-plane upper critical field anisotropy by SQUID magnetometry show a ratio of 0.92 at 4.2 K, consistent with the Ginzburg-Landau analysis. C1 LUCENT TECHNOL,AT&T BELL LABS,MURRAY HILL,NJ 07974. IOWA STATE UNIV,AMES LAB,AMES,IA 50011. IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. UNIV NAPLES FEDERICO II,DIPARTIMENTO SCI FIS,NAPLES,ITALY. BAR ILAN UNIV,DEPT PHYS,RAMAT GAN,ISRAEL. RP DeWilde, Y (reprint author), ARGONNE NATL LAB,DIV MAT SCI,SCI & TECHNOL CTR SUPERCONDUCT,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Iavarone, Maria/C-3628-2008; Aranson, Igor/I-4060-2013; Canfield, Paul/H-2698-2014; Koshelev, Alexei/K-3971-2013; OI Koshelev, Alexei/0000-0002-1167-5906; De Wilde, Yannick/0000-0002-5973-1460 NR 25 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 355 EP 358 DI 10.1016/S0921-4534(97)00268-2 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400095 ER PT J AU Borsa, F Carretta, P Corti, M Rigamonti, A Suh, BJ AF Borsa, F Carretta, P Corti, M Rigamonti, A Suh, BJ TI Thermal fluctuations of flux lines and nuclear relaxation SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SPIN-ECHO DECAY; Y-89 NMR; SUPERCONDUCTORS; LATTICE; ANISOTROPY; YBA2CU4O8; DYNAMICS; VORTICES AB The study of thermal motion of flux lines as evidenced in NMR measurements is reviewed in the light of our recent results on the nuclear spin-lattice and spin-spin relaxation rates in anisotropic HTcSC YBa2Cu4O8 and HgBa2CuO4+delta. C1 ISU,AMES LAB,USDOE,AMES,IA. ISU,DEPT PHYS & ASTRON,AMES,IA. MPI,CNRS,GRENOBLE HIGH MAGNET FIELD LAB,F-30842 GRENOBLE 9,FRANCE. RP Borsa, F (reprint author), UNIV PAVIA,DIPARTIMENTO FIS A VOLTA,I-27100 PAVIA,ITALY. NR 10 TC 2 Z9 2 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 AUG PY 1997 VL 282 BP 359 EP 362 DI 10.1016/S0921-4534(97)00269-4 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400096 ER PT J AU KrusinElbaum, L Lopez, D Thompson, JR Wheeler, R Ullmann, J Tsuei, CC Chu, CW Lin, QM AF KrusinElbaum, L Lopez, D Thompson, JR Wheeler, R Ullmann, J Tsuei, CC Chu, CW Lin, QM TI A path to high-field performance of cuprate superconductors above 100 K with fission induced defects SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SPLAYED COLUMNAR DEFECTS; TEMPERATURE; CRYSTALS; HGBA2CUO4+DELTA; PRESSURE; TAPES; FLUX AB We demonstrate a method by which we expand the useful range of cuprate superconductors to above 100 K and enhance persistent currents by orders of magnitude in fields of several Tesla - namely fission of Hg nuclei within Hg-cuprates with 0.8 GeV protons. The fission process allows ''doping'' these cuprates with strongly pinning splayed columnar defects. The technique could be technologically relevant, since it is not limited by the short penetration range of heavier particles (or ions) and could permit modification of larger superconducting objects, such as magnets. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. OHIO STATE UNIV,COLUMBUS,OH 43210. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV HOUSTON,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77204. RP KrusinElbaum, L (reprint author), IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598, USA. NR 19 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 375 EP 378 DI 10.1016/S0921-4534(97)00279-7 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400100 ER PT J AU Xiang, XD Schultz, PG AF Xiang, XD Schultz, PG TI The combinatorial synthesis and evaluation of functional materials SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB In order to increase the rate of materials discovery and optimization, as well as increase our understanding of increasingly complex modem materials, we have developed the strategyies and technologies for the combinatorial synthesis and evaluation of functional materials. In this approach large collections (libraries) of different materials are rapidly synthesized, processed and screened for specific properties of interest. RP Xiang, XD (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Xiang, Xiaodong/A-9445-2012; Xiang, Xiaodong/A-5936-2017 NR 4 TC 32 Z9 32 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 428 EP 430 DI 10.1016/S0921-4534(97)00297-9 PN 1 PG 3 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400114 ER PT J AU Tetenbaum, M Hash, M Tani, BS Luo, JS Maroni, VA AF Tetenbaum, M Hash, M Tani, BS Luo, JS Maroni, VA TI Thermodynamic and nonstoichiometric behavior of the lead-doped and lead-free Bi-2212 systems SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Electromotive force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on lead-doped and lead-free superconducting ceramics in the temperature range similar to 700-815 degrees C by means of an oxygen titration technique. Equations for the variation of oxygen partial pressure with composition and temperature have been derived from our EMF measurements. Thermodynamic assessments of the partial molar quantities (O-2) and (O-2) for lead-doped Bi-2212 and lead-free Bi-2212 indicate that the solid-state decomposition of these bismuth cuprates at low oxygen partial pressure can be represented by the diphasic CuO-Cu2O system. Comparison of these results with lead-doped Bi-2223 in powder and silver sheath form will be presented. RP Tetenbaum, M (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 2 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 441 EP 442 DI 10.1016/S0921-4534(97)00304-3 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500003 ER PT J AU Goodwin, TJ Shelton, RN Radousky, HB AF Goodwin, TJ Shelton, RN Radousky, HB TI Relating structural properties and oxygen content to the electronic and magnetic states of (Eu1.5-xPrxCe0.5)Sr2Cu2NbO10-delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Structural parameters, phase purity, and oxygen stoichiometry for the (Eu1.5-xPrxCe0.5)Sr2Cu2NbO10-delta system are studied using X-ray diffraction, Rietveld refinement, and thermogravimetric analysis. Relationships between these properties and the suppression of T-c and unusual magnetism in these materials are examined. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Goodwin, TJ (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, 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 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 745 EP 746 DI 10.1016/S0921-4534(97)00385-7 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500154 ER PT J AU Salvador, PA Otzschi, KD Zhang, H Dabrowski, B Jorgensen, JD Mason, TO Marks, LD Poeppelmeier, KR AF Salvador, PA Otzschi, KD Zhang, H Dabrowski, B Jorgensen, JD Mason, TO Marks, LD Poeppelmeier, KR TI Genesis of superconductivity in the layered cuprates: (ACuO(25))(2)(ATiO(3))(m); 2<=m<=4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB The internal chemistry of the quadruple perovskite Ln'Ln '' Ba2Cu2Ti2O11 (Ln'Ln '' = NdDy), such as solid solution behavior, stable defect species, and oxidation behavior, has been investigated by structural and physical property measurements and related to the inner architecture of these interesting layered compounds. C1 NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RI Mason, Thomas/B-7528-2009; Marks, Laurence/B-7527-2009; Salvador, Paul/A-9435-2011 OI Salvador, Paul/0000-0001-7106-0017 NR 5 TC 0 Z9 0 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 AUG PY 1997 VL 282 BP 959 EP 960 DI 10.1016/S0921-4534(97)00594-7 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500261 ER PT J AU Takeuchi, T Ding, H Campuzano, JC Yokoya, T Takahashi, T Chong, I Terashima, T Takano, M AF Takeuchi, T Ding, H Campuzano, JC Yokoya, T Takahashi, T Chong, I Terashima, T Takano, M TI ARPES studies of Pb substituted Bi2201 compounds SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID FERMI-SURFACE; PHOTOEMISSION; STATE AB We report angle-resolved photoemission of overdoped B1.80Pb0.38Sr2.01CuO6 with different Te's of 4, 8, and 20 K. All samples show similar large Fermi surfaces, centered at (pi, pi). However, the spectral function linewidth decreases as doping increases. The 4K sample is found to have the typical Fermi liquid linewidth. Comparison is also made to the two layer Bi2Sr2CaCu2O8 compound. C1 NAGOYA UNIV,DEPT CRYSTALLINE MAT SCI,NAGOYA,AICHI 46401,JAPAN. UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60607. TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 98077,JAPAN. KYOTO UNIV,INST CHEM RES,UJI,KYOTO 611,JAPAN. RP Takeuchi, T (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Tohoku, Arpes/A-4890-2010; Takahashi, Takashi/E-5080-2010; Campuzano, Juan Carlos/G-4358-2012; YOKOYA, Takayoshi/B-1478-2011; OI Ding, Hong/0000-0003-4422-9248 NR 8 TC 5 Z9 5 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 999 EP 1000 DI 10.1016/S0921-4534(97)00572-8 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500281 ER PT J AU Lei, M Migliori, A Ledbetter, H AF Lei, M Migliori, A Ledbetter, H TI Acoustic evidence against BCS behavior in monocrystal YBa2Cu3O7 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID ANELASTIC RELAXATION AB Using a detwinned YBa2Cu3O7 monocrystal and acoustic-resonance spectroscopy, we measured internal friction Q(-1) = Delta f/f(r) through the 91-K superconducting-transition temperature. We show measurements for the first ten macroscopic resonance frequencies f(r). None of the modes show classic BCS-model behavior based on simple-pairing, isotropic-s-electron, weak-coupling assumptions. Beside being non-BCS-like, essentially every mode behaves differently, suggesting a strongly anisotropic energy gap Delta(k), and practically ruling out any simple Fermi-surface gap function, especially s-wave. Some modes actually show increasing Q(-1) upon cooling below T-c, suggesting either strong Fermi-surface changes or lattice-relaxation mechanisms. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Lei, M (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 8 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1077 EP 1078 DI 10.1016/S0921-4534(97)00643-6 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500320 ER PT J AU Brandstatter, G Bohmer, C Weber, HW Veal, BW AF Brandstatter, G Bohmer, C Weber, HW Veal, BW TI Experimental study of the lower critical field in high-T-c single crystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Employing SQUID magnetometry and novel measuring and evaluation techniques, precise information on the first penetration field can be obtained and used to extract H-c1. Tl- and Bi-based as well as a series of oxygen deficient Y-123 high T-c superconducting single crystals were investigated (H/ /c). In all cases, H-c1 is smaller than previously reported and can be described by BCS-theory. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Brandstatter, G (reprint author), OSTERRICH UNIV,ATOMINST,SHUTTELSTR 115,A-1020 VIENNA,AUSTRIA. NR 6 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1309 EP 1310 DI 10.1016/S0921-4534(97)00719-3 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600094 ER PT J AU Bommeli, F Degiorgi, L Wachter, P Cho, BK Canfield, PC Chau, R Maple, MB AF Bommeli, F Degiorgi, L Wachter, P Cho, BK Canfield, PC Chau, R Maple, MB TI Optical evidence of the superconducting gap in LNi2B2C (L = Lu and Y) SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID LUNI2B2C AB We have measured the optical conductivity of LuNi2B2C and YNi2B2C compounds. In the superconducting state we found clear evidence of a superconducting gap, indicative of a moderate-to-strong coupling limit for the pairing mechanism. C1 IOWA STATE UNIV,AMES LAB,AMES,IA 50011. IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. UNIV CALIF SAN DIEGO,INST PURE & APPL PHYS SCI,LA JOLLA,CA 92093. RP Bommeli, F (reprint author), ETH ZURICH,FESTKORPERPHYS LAB,CH-8093 ZURICH,SWITZERLAND. RI Canfield, Paul/H-2698-2014 NR 9 TC 1 Z9 1 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 AUG PY 1997 VL 282 BP 1475 EP 1476 DI 10.1016/S0921-4534(97)00844-7 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600177 ER PT J AU Li, Q Tsay, YN Suenaga, M Gu, GD Koshizuka, N AF Li, Q Tsay, YN Suenaga, M Gu, GD Koshizuka, N TI Superconducting coupling along the c-axis of [001] twist grain-boundaries in Bi2Sr2CaCu2O8+delta bicrystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB We report experimental studies of transport properties of superconducting Bi2Sr2CaCu2O8+delta (Bi-2212) bicrystals with various degrees of high quality [001] twist grain boundaries. We find similar resistive onset temperature and field for both the grain-boundary and the constituent single crystals. Critical current across the grain boundaries is essentially independent of twist angle. These results show that the strength of superconducting coupling along the c-axis of [001] twist grain boundaries does no depend on misorientation angle. C1 ISTEC,SUPERCONDUCT RES LAB,TOKYO 135,JAPAN. RP Li, Q (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 5 TC 16 Z9 16 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 AUG PY 1997 VL 282 BP 1495 EP 1496 DI 10.1016/S0921-4534(97)00854-X PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600187 ER PT J AU Lu, L Jia, YX Fuhrer, M Zettl, A AF Lu, L Jia, YX Fuhrer, M Zettl, A TI Fluctuational Ettingshausen effect in single crystals of YBa2Cu3O7-delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SUPERCONDUCTORS; TRANSPORT; ENTROPY AB We have studied the Ettingshausen effect in single crystals of YBa2Cu3O7-delta near the superconducting transition temperature T-c. Two distinct regimes were found in the field dependence of the Ettingshausen coefficient - a low-field regime where flux-flow dominates and a high-field regime where fluctuation dominates. The result is in agreement with Ullah and Dorsey's scaling theory for fluctuational Ettingshausen effect, and seems also consistent with Maki's mean-field theory when the temperature of the sample is several Kelvins away from T-c. C1 CHINESE ACAD SCI,CTR CONDENSED MATTER PHYS,BEIJING 100080,PEOPLES R CHINA. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Lu, L (reprint author), CHINESE ACAD SCI,INST PHYS,POB 603,BEIJING 100080,PEOPLES R CHINA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X 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 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1547 EP 1548 DI 10.1016/S0921-4534(97)00878-2 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600213 ER PT J AU Shenoy, SR Subrahmanyam, V Bishop, AR AF Shenoy, SR Subrahmanyam, V Bishop, AR TI Local dynamical d-wave pairing in layered quantum paraelectric superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Elastic c-axis coupling between a (CuO) buckled a-b plane of buckling angle s much less than 1, and a ferroelectric (oxygen) layer, produces novel omega+/-((q) over right arrow) modes, from s-induced mixing of 'a-b' and 'c' direction vibrations. The Cooper interaction coupling, similar to(w(+)(2)-w(-)(2))(-1)similar to s(-1)much greater than 1, is strongly resonance-enhanced and anisotropic (similar to d-wave), yielding dynamical local pairing. C1 INDIAN INST TECHNOL,DEPT PHYS,KANPUR 208016,UTTAR PRADESH,INDIA. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Shenoy, SR (reprint author), INT CTR THEORET PHYS,POB 586,I-34100 TRIESTE,ITALY. NR 7 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1645 EP 1646 DI 10.1016/S0921-4534(97)00906-4 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600262 ER PT J AU Wellein, G Fehske, H Buttner, H Bishop, AR AF Wellein, G Fehske, H Buttner, H Bishop, AR TI On the stability of polaronic superlattices in strongly coupled electron-phonon systems SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID CHARGE; MODEL AB We investigate the interplay of electron-phonon (EP) coupling and strong electronic correlations in the frame of the two-dimensional (2D) Holstein t-J model (HtJM), focusing on polaronic ordering phenomena for the quarter-filled band case. The use of direct Lanczos diagonalization on finite lattices allows us to include the effects of quantum phonon fluctuations in the calculation of spin/charge structure factors and hole-phonon correlation functions. In the adiabatic strong coupling regime we found evidence for ''self-localization'' of polaronic carriers in a (pi, pi) charge-modulated structure, a type of superlattice solidification reminiscent of those observed in the nickel perovskites La2-xSrxNiO4+y. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Wellein, G (reprint author), UNIV BAYREUTH,INST PHYS,POB 101251,D-95440 BAYREUTH,GERMANY. NR 7 TC 2 Z9 2 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 AUG PY 1997 VL 282 BP 1827 EP 1828 DI 10.1016/S0921-4534(97)01042-3 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600353 ER PT J AU Fehske, H Wellein, G Bauml, B Silver, RN AF Fehske, H Wellein, G Bauml, B Silver, RN TI Spectral properties of the 2D Holstein t-J model SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Employing the Lanczos algorithm in combination with a kernel polynomial moment expansion (KPM) and the maximum entropy method (MEM), we show a way of calculating charge and spin excitations in the Holstein t-J model, including the full quantum nature of phonons. To analyze polaron band formation we evaluate the hole spectral function for a wide range of electron-phonon coupling strengths. For the first time, we present results for the optical conductivity of the 2D Holstein t-J model. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Fehske, H (reprint author), UNIV BAYREUTH,INST PHYS,POB 101251,D-95440 BAYREUTH,GERMANY. 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 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1829 EP 1830 DI 10.1016/S0921-4534(97)01044-7 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600354 ER PT J AU Zuo, F Su, X Alexandrakis, GC Schlueter, JA Kelly, ME Williams, JM AF Zuo, F Su, X Alexandrakis, GC Schlueter, JA Kelly, ME Williams, JM TI Interlayer transport in the organic superconductor kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID MAGNETORESISTANCE AB Interlayer magnetoresistance as a function of field and temperature with fields parallel and perpendicular to the current direction in the organic superconductor kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br has been measured. For H parallel to I, the isothermal magnetoresistance R(H) displays a peak effect as a function of field. For H perpendicular to I, R(I-I) increases monotonically with increasing field. Comparison of the peak field with the H-c2(T) data suggests that the peak in R(R) occurs in the mixed state. We analyze the data in terms of the resistively shunted Josephson junction model and the density of states fluctuation model. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Zuo, F (reprint author), UNIV MIAMI,DEPT PHYS,CORAL GABLES,FL 33124, USA. NR 8 TC 3 Z9 3 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 AUG PY 1997 VL 282 BP 1901 EP 1902 DI 10.1016/S0921-4534(97)01136-2 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600390 ER PT J AU Fuhrer, MS Cherrey, K Zettl, A AF Fuhrer, MS Cherrey, K Zettl, A TI Carbon isotope effect in single-crystal Rb3C60 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SUPERCONDUCTING RB3C60; C60 AB We have synthesized single crystals of isotopically enriched Rb3C60. The very sharp superconducting transitions in single crystal superconducting fullerides allow us to determine the isotope effect on the superconducting transition temperature, T-c, with unprecedented accuracy. We find that the carbon isotope shift exponent alpha(carbon) for 99% C-13 substitution is 0.21+/-0.012, significantly smaller than other values reported in the literature(1-6). This, coupled with the near-zero rubidium isotope effect reported by B. Burk et. al.(7), should place considerable constraints on any theoretical model of superconductivity in the alkali fullerides. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Fuhrer, MS (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X NR 9 TC 0 Z9 0 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1917 EP 1918 DI 10.1016/S0921-4534(97)01010-1 PN 3 PG 2 WC Physics, Applied SC Physics GA XZ906 UT WOS:A1997XZ90600398 ER PT J AU Fuhrer, MS Ino, K Oka, K Nishihara, Y Zettl, A AF Fuhrer, MS Ino, K Oka, K Nishihara, Y Zettl, A TI Josephson vortex lattice melting in Bi2Sr2CaCu2O8 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB The Josephson vortex lattice state of the highly anisotropic high-T-c superconductor Bi2Sr2CaCu2O8 has been probed by measurements of the out-of-plane (c-axis) resistivity as a function of temperature, current density, magnetic field strength H, and magnetic field orientation angle theta. Anomalous dissipation is observed below a critical temperature identified as the melting transition of the Josephson vortex lattice. The critical T-H and T-theta phase boundaries are determined. The melting transition is interpreted as a Kosterlitz-Thouless depairing of interlayer vortex/anti-vortex pairs. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. ELECTROTECH LAB,TSUKUBA,IBARAKI 305,JAPAN. RP Fuhrer, MS (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X NR 7 TC 3 Z9 3 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 AUG PY 1997 VL 282 BP 2041 EP 2042 DI 10.1016/S0921-4534(97)01111-8 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700050 ER PT J AU Recchia, CH Martindale, JA Pennington, CH Hults, WL Smith, JL AF Recchia, CH Martindale, JA Pennington, CH Hults, WL Smith, JL TI NMR spin echo experiments as probes of vortex dynamics in YBa2Cu3O7 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID Y-89 NMR; RELAXATION; DECAY AB We report Y-89 and O-17 NMR (9 Tesla) spin echo decay (T-2) measurements for YBa2CU3O7 We correct the results to remove effects of (CU)-C-63,65 dipolar coupling in order to isolate effects of vortex dynamics. We confirm vortex localization in the vortex solid state with rms displacements consistent with Langevin dynamical theory, but with motional dynamics at time scales some 10(6) times slower than predicted. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Recchia, CH (reprint author), OHIO STATE UNIV,DEPT PHYS,174 W 18TH AVE,COLUMBUS,OH 43221, USA. 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 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 2065 EP 2066 DI 10.1016/S0921-4534(97)01132-5 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700062 ER PT J AU Boekema, C Cooke, DW Merton, M Vera, O AF Boekema, C Cooke, DW Merton, M Vera, O TI mu SR study of the grain-size dependence of Y1237 vortex states SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SPIN-ROTATION; SUPERCONDUCTORS; YBA2CU3O7-DELTA; PENETRATION; SYMMETRY AB The grain-size dependence of the magnetic field distributions in YBa2Cu3O7-delta (Y1237) vortex states has been studied. Strong deviations from type-II BCS-like behavior are observed. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Boekema, C (reprint author), SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95112, USA. NR 15 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 AUG PY 1997 VL 282 BP 2069 EP 2070 DI 10.1016/S0921-4534(97)01139-8 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700064 ER PT J AU Ling, XS Budnick, JI Veal, BW AF Ling, XS Budnick, JI Veal, BW TI Peak effect and its disappearance in YBCO superconducting crystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID HIGH-TC SUPERCONDUCTORS; FLUX; LATTICE AB The anomalous temperature dependence of vortex pinning, known as the peak effect, in a YBa2Cu3O6.55 crystal is studied by an AC susceptibility technique. The peak effect is found to appear only at the intermediate field range. The onset of the peak effect in the H-T plane exhibits a reentrant behavior, reminiscent of the Nelson phase diagram for 3D vortex-lattice melting. C1 UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06269. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Ling, XS (reprint author), BROWN UNIV,DEPT PHYS,PROVIDENCE,RI 02912, USA. RI Ling, Xinsheng/A-9219-2008 NR 12 TC 17 Z9 17 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 2191 EP 2192 DI 10.1016/S0921-4534(97)01235-5 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700125 ER PT J AU VlaskoVlasov, VK Welp, U Crabtree, GW Kabanov, VV Nikitenko, VI AF VlaskoVlasov, VK Welp, U Crabtree, GW Kabanov, VV Nikitenko, VI TI Meissner holes and turbulent flux structures in high-Tc superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB The magnetic flux structure in HTSC single crystal plates during their remagnetization in unidirectional and rotating fields is imaged using advanced magneto-optical techniques. It is found that bending of the flux lines is crucial for the remagnetization scenario even in the case of thin plates in parallel fields. Flux bending results in the formation of flux free cylinders (Meissner holes) surrounded by closed vortex loops. Essential increase of the current along the holes stipulates instabilities and appearance of unusual turbulent current and flux patterns. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP VlaskoVlasov, VK (reprint author), RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,RUSSIA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 2231 EP 2232 DI 10.1016/S0921-4534(97)01186-6 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700145 ER PT J AU Wijngaarden, RJ Surdeanu, R Griessen, R Menovsky, AA Fendrich, J Kwok, WK AF Wijngaarden, RJ Surdeanu, R Griessen, R Menovsky, AA Fendrich, J Kwok, WK TI Measurement of local currents in superconductors using an in-situ high field magneto-optical microscope SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB A contactless method is used to measure the local current density in superconductors at fields up to 7 T with a spatial resolution better than 1 mu m. The local currents are derived from magneto-optical images using a powerful inversion scheme. Various illustrative applications are discussed. C1 VRIJE UNIV AMSTERDAM,FAC PHYS & ASTRON,NL-1081 HV AMSTERDAM,NETHERLANDS. UNIV AMSTERDAM,VAN DER WAALS ZEEMAN INST,NL-1018 XE AMSTERDAM,NETHERLANDS. ARGONNE NATL LAB,ARGONNE,IL 60439. RP Wijngaarden, RJ (reprint author), VRIJE UNIV AMSTERDAM,INST COMPAS,DE BOELELAAN 1081,NL-1081 HV AMSTERDAM,NETHERLANDS. NR 2 TC 3 Z9 3 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 AUG PY 1997 VL 282 BP 2291 EP 2292 DI 10.1016/S0921-4534(97)01241-0 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700175 ER PT J AU Xu, M Zhang, K Jaeger, HM Hinks, DG Crabtree, GW Goretta, KC Zhao, Y Choi, CH AF Xu, M Zhang, K Jaeger, HM Hinks, DG Crabtree, GW Goretta, KC Zhao, Y Choi, CH TI Flux jumps in Y-123 and La-214 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SUPERCONDUCTORS; TEMPERATURE; STABILITY; CRYSTAL; GROWTH; CREEP AB The magnetization of melt-textured Y-123 and single crystal La-214 has been measured in magnetic field up to 5.5 T using a SQUID magnetometer. Partial and nearly complete flux jumps were observed at about 10 K in Y-123 and 5 K in La-214 single crystals, respectively. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV NEW S WALES,SYDNEY,NSW 2052,AUSTRALIA. RP Xu, M (reprint author), UNIV CHICAGO,JAMES FRANCK INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 12 TC 2 Z9 2 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 AUG PY 1997 VL 282 BP 2359 EP 2360 DI 10.1016/S0921-4534(97)01311-7 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700209 ER PT J AU Hanaguri, T Tsuchiya, Y Sakamoto, S Maeda, A Steel, DG AF Hanaguri, T Tsuchiya, Y Sakamoto, S Maeda, A Steel, DG TI Josephson plasma resonance in the mixed sate of Bi2Sr2CaCu2Oy containing columnar defects SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE AB Two distinct peaks were found in the magnetic-field dependence of the microwave absorption in Bi2Sr2CaCu2Oy containing columnar defects. The peak at higher field is originated from the Josephson plasma resonance (JPR) and is shifted rapidly to higher fields with increasing defect densities. This result implies that vortices other than those trapped by columnar defects were also aligned through the vortex-vortex interaction. The peak at lower field may be caused by the novel JPR originated from the non-monotonic field dependence of the interlayer critical current density. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Hanaguri, T (reprint author), UNIV TOKYO,DEPT BASIC SCI,MEGURO KU,3-8-1 KOMABA,TOKYO 153,JAPAN. RI Hanaguri, Tetsuo/I-6710-2012; Tsuchiya, Yoshishige/B-6127-2013 OI Hanaguri, Tetsuo/0000-0003-2896-0081; NR 5 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 2375 EP 2376 PN 4 PG 2 WC Physics, Applied SC Physics GA YA417 UT WOS:A1997YA41700217 ER PT J AU Tranquada, JM AF Tranquada, JM TI Charge stripes and spin correlations in copper-oxide superconductors SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID NEUTRON-SCATTERING; MAGNETIC FLUCTUATIONS; HOLES; ANTIFERROMAGNETS; LA2-XBAXCUO4; LA2-XSRXCUO4; YBA2CU3O6.15; DYNAMICS; LA2CUO4; GAP AB Recent neutron diffraction studies have yielded evidence that, in a particular cuprate family, holes doped into the CuO2 planes segregate into stripes that separate antiferromagnetic domains. Here it is shown that such a picture provides a quantitatively consistent interpretation of the spin fluctuations measured by neutron diffraction in La1.85Sr0.15CuO4 and YBa2Cu3O6+x. RP Tranquada, JM (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RI Tranquada, John/A-9832-2009 OI Tranquada, John/0000-0003-4984-8857 NR 28 TC 41 Z9 42 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 EI 1873-2143 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 166 EP 169 DI 10.1016/S0921-4534(97)00252-9 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400046 ER PT J AU Emery, VJ Kivelson, SA Zachar, O AF Emery, VJ Kivelson, SA Zachar, O TI Pairing and phase coherence in high temperature superconductors SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID ANGLE-RESOLVED PHOTOEMISSION; DIMENSIONAL ELECTRON-GAS; HIGH-TC SUPERCONDUCTOR; NORMAL-STATE; ORDER-PARAMETER; MODEL; BI2SR2CACU2O8+DELTA; CONDUCTIVITY; ANISOTROPY; SEPARATION AB Mobile holes in an antiferromagnetic insulator form a slowly fluctuating array of quasi one-dimensional metallic stripes, which induce a spin gap or pseudogap in the intervening Mott-insulating regions. The mobile holes on an individual stripe acquire a spin gap via pair hopping between the stripe and its environment; i.e. via a magnetic analog of the usual superconducting proximity effect. This process is the analog of pairing in conventional superconductors. At non-vanishing stripe densities, Josephson coupling between stripes produces a dimensional crossover to a state with long-range superconducting phase coherence. In contrast to conventional superconductors, the superconducting state is characterised by a high density of (spin) pairs, but the phase stiffness, which is determined by the density and mobility of holes on the stripes, is very low. C1 UNIV CALIF LOS ANGELES, DEPT PHYS, LOS ANGELES, CA 90095 USA. RP Emery, VJ (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. NR 42 TC 24 Z9 24 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 174 EP 177 DI 10.1016/S0921-4534(97)00255-4 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400048 ER PT J AU Murin, Y Blann, M Jakobsson, B AF Murin, Y Blann, M Jakobsson, B TI The isotopic effect as a clock for nuclear fragmentation SO PHYSICA SCRIPTA LA English DT Article ID INTERMEDIATE-MASS FRAGMENTS; HEAVY-ION COLLISIONS; TIME-SCALE; EMISSION TIME; AR-36+AU-197 COLLISIONS; E/A=50 MEV; MULTIFRAGMENTATION; ENERGY; DECAY; PROBE AB Experimental ratios between the emission rates of light fragments (Li, Be, B and C) from (112,(116))Sn and Sn-124 targets are compared to predictions from a model which combines the Boltzmann master equation to describe the dynamics and preequilibrium particle emission and the statistical multifragmentation model to describe the final breakup. Since secondary decay and the choice of freeze-out volume affect these ratios very little this comparison can be used to estimate the excitation energy at the instant of fragmentation in a self-consistent way. The preequilibrium nucleon emission governs the time dependence of the excitation energy available for fragment production which is nearly the same for all Sn isotopes. Therefore the yield ratios can be used to estimate the fragmentation time. Data from 1 GeV proton- and 200 MeV He-4 induced reactions indicate short fragmentation times - 20-40 fm/c while 32 A MeV N-14 induced reactions seems to exhibit much longer times - 300-400 fm/c. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. VG KHLOPIN RADIUM INST,SU-197022 ST PETERSBURG,RUSSIA. RP Murin, Y (reprint author), LUND UNIV,DEPT PHYS,SOLVEGATAN 14,S-22362 LUND,SWEDEN. NR 38 TC 2 Z9 2 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD AUG PY 1997 VL 56 IS 2 BP 137 EP 140 DI 10.1088/0031-8949/56/2/002 PG 4 WC Physics, Multidisciplinary SC Physics GA XQ463 UT WOS:A1997XQ46300002 ER PT J AU Girndt, AA Jahnke, F Knorr, AZ Koch, SW Chow, WW AF Girndt, AA Jahnke, F Knorr, AZ Koch, SW Chow, WW TI Multi-band bloch equations and gain spectra of highly excited II-VI semiconductor quantum wells SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH LA English DT Article; Proceedings Paper CT Japanese-German Seminar on II-Vi Semiconductors CY FEB 23-MAR 27, 1997 CL BREMEN, GERMANY ID STIMULATED-EMISSION; LASERS; HETEROSTRUCTURES AB Quasi-equilibrium excitation dependent optical probe spectra of II-VI semiconductor quantum wells at room temperature are investigated within the framework of multi-band semiconductor Bloch equations. The calculations include correlation effects beyond the Hartree-Fock level which describe dephasing, interband Coulomb correlations and band-gap renormalization in second Born approximation. In addition to the carrier-Coulomb interaction, the influence of carrier-phonon scattering and inhomogeneous broadening is considered. The explicit calculation of single particle properties like band structure and dipole matrix elements using k.p theory makes it possible to investigate various II-VI material combinations. Numerical results are presented for CdZnSe/ZnSe and CdZnSe/MgZnSSe semiconductor quantum-well systems. C1 UNIV MARBURG, ZENTRUM MAT WISSENSCH, D-35032 MARBURG, GERMANY. SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. RP Girndt, AA (reprint author), UNIV MARBURG, FACHBEREICH PHYS, RENTHOF 5, D-35032 MARBURG, GERMANY. NR 17 TC 74 Z9 74 U1 0 U2 3 PU AKADEMIE VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0370-1972 J9 PHYS STATUS SOLIDI B JI Phys. Status Solidi B-Basic Res. PD AUG PY 1997 VL 202 IS 2 BP 725 EP 739 DI 10.1002/1521-3951(199708)202:2<725::AID-PSSB725>3.0.CO;2-K PG 15 WC Physics, Condensed Matter SC Physics GA XT562 UT WOS:A1997XT56200015 ER PT J AU Marrs, RE Elliott, SR Scofield, JH AF Marrs, RE Elliott, SR Scofield, JH TI Measurement of electron-impact ionization cross sections for hydrogenlike high-Z ions SO PHYSICAL REVIEW A LA English DT Article ID CHARGED IONS; RELATIVISTIC CALCULATIONS AB Electron-impact ionization cross sections have been measured for the hydrogenlike ions of molybdenum, dysprosium, gold, and bismuth at selected electron energies between 1.3 and 3.9 times threshold. The cross sections were obtained from x-ray measurements of the equilibrium ionization balance in an electron beam ion trap. The measured cross sections agree with recent relativistic distorted-wave calculations that include both the Moeller interaction and exchange. RP Marrs, RE (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 22 TC 36 Z9 36 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1997 VL 56 IS 2 BP 1338 EP 1345 DI 10.1103/PhysRevA.56.1338 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800040 ER PT J AU Armen, GB Southworth, SH Levin, JC Arp, U LeBrun, T MacDonald, MA AF Armen, GB Southworth, SH Levin, JC Arp, U LeBrun, T MacDonald, MA TI Xenon spectator and diagram L-3-M4,5M4,5 Auger intensities near the L-3 threshold SO PHYSICAL REVIEW A LA English DT Article ID POST-COLLISION INTERACTION; SYNCHROTRON RADIATION; POSTCOLLISION INTERACTION; SPECTRA; STATES AB Calculations based on the theory of radiationless resonant Raman scattering are employed in the interpretation of new Xe L-3-M4,5M4,5 Auger spectra recorded using synchrotron radiation tuned to energies across the L-3 edge. Fits of theoretical line shapes to the spectra are employed in separating intensities due to nd spectator (resonant) and diagram Auger processes. Near-threshold Anger intensity, previously attributed to diagram decay, is found to be due to the large-n spectator lines that result from postcollision-interaction-induced ''recapture'' of threshold photoelectrons to nd orbitals. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NIST,GAITHERSBURG,MD 20899. SERC,DARESBURY LAB,ENGN & PHYS SCI RES COUNCIL,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. RP Armen, GB (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. RI Arp, Uwe/C-2854-2009; OI Arp, Uwe/0000-0002-6468-9455 NR 18 TC 22 Z9 22 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1997 VL 56 IS 2 BP R1079 EP R1082 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800005 ER PT J AU Diehl, S Cubaynes, D Chung, KT Wuilleumier, FJ Kennedy, ET Bizau, JM Journel, L Blancard, C VoKy, L Faucher, P Hibbert, A Berrah, N Morgan, TJ Bozek, J Schlachter, AS AF Diehl, S Cubaynes, D Chung, KT Wuilleumier, FJ Kennedy, ET Bizau, JM Journel, L Blancard, C VoKy, L Faucher, P Hibbert, A Berrah, N Morgan, TJ Bozek, J Schlachter, AS TI Photoelectron spectroscopy measurements and theoretical calculations of the lowest doubly hollow lithium state SO PHYSICAL REVIEW A LA English DT Article ID ATOMIC LITHIUM AB We have measured, using electron spectroscopy, the lowest-energy doubly hollow lithium triply excited (3l3l'3l '') P-2 state. Energies, widths, and partial cross sections have been measured and calculated using the saddle-point technique and the R-matrix approximation. Our results show good agreement between experimental and theoretical data for the energy and the width of the doubly hollow state. C1 N CAROLINA STATE UNIV,DEPT PHYS,RALEIGH,NC 27695. DUBLIN CITY UNIV,SCH PHYS SCI,DUBLIN 9,IRELAND. CTR ETUD LIMEIL VALENTON,DRIF,F-94195 VILLENEUVE ST GEO,FRANCE. OBSERV COTE AZUR,F-06304 NICE,FRANCE. QUEENS UNIV BELFAST,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. WESTERN MICHIGAN UNIV,KALAMAZOO,MI 49008. WESLEYAN UNIV,MIDDLETOWN,CT 06457. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,ADV LIGHT SOURCE,BERKELEY,CA 94720. RP Diehl, S (reprint author), UNIV PARIS 11,LAB SPECT ATOM & ION,BATIMENT 350,F-91405 ORSAY,FRANCE. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 17 TC 34 Z9 34 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1997 VL 56 IS 2 BP R1071 EP R1074 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800003 ER PT J AU Mancini, JD Prie, JD Zhou, Y Bowen, SP AF Mancini, JD Prie, JD Zhou, Y Bowen, SP TI Linear Jahn-Teller effect: A connected-moments approach SO PHYSICAL REVIEW B LA English DT Article ID COUPLED-CLUSTER APPROXIMATION; HIGH-TC SUPERCONDUCTIVITY; GROUND-STATE ENERGY; EXPANSION; MODEL; SYSTEM AB The ground-state energy of the linear E x epsilon Jahn-Teller effect is obtained using a connected-moments expansion. The calculation is straightforward and leads to a set of simple algebraic expressions for the connected moments of the Hamiltonian. This is then compared to a recent calculation wherein a coupled-cluster scheme has been applied resulting in a set of thirteen nonlinear coupled algebraic equations. C1 UNIV MINNESOTA,DEPT PHYS,MINNEAPOLIS,MN 55455. UNIV MINNESOTA,MINNESOTA SUPERCOMP INST,MINNEAPOLIS,MN 55455. ARGONNE NATL LAB,ARGONNE,IL 60439. RP Mancini, JD (reprint author), FORDHAM UNIV,DEPT PHYS,BRONX,NY 10458, USA. NR 30 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1997 VL 56 IS 5 BP 2309 EP 2311 DI 10.1103/PhysRevB.56.2309 PG 3 WC Physics, Condensed Matter SC Physics GA XQ619 UT WOS:A1997XQ61900008 ER PT J AU Kanner, GS Strouse, GF Swanson, BI Sinclair, M Jiang, JP Peyghambarian, N AF Kanner, GS Strouse, GF Swanson, BI Sinclair, M Jiang, JP Peyghambarian, N TI Subpicosecond dynamics of excitons and photoexcited intrinsic polarons in the quasi-one-dimensional solid PtCl SO PHYSICAL REVIEW B LA English DT Article ID BRIDGED MIXED-VALENCE; ULTRAFAST OPTICAL-RESPONSE; 3RD-HARMONIC GENERATION; CONJUGATED POLYMERS; RESONANCE RAMAN; METAL-COMPLEXES; PHOTOINDUCED DEFECTS; 2-PHOTON ABSORPTION; MX CHAINS; PLATINUM AB Subpicosecond transient absorption (TA) spectroscopy was used to identify excited states, and to measure their relaxation kinetics as a function of excitation wavelength in the halogen-bridged transition-metal (MX) compound PtCl. For pump photon energies E-pump between 1.3 and 1.8 eV, below the threshold for exciton formation, intrinsic polarons are photoexcited and decay within 1-3 ps. Excitation into the exciton absorption tail (2.0-2.3 eV) yields singlet excitons that rapidly decay into an even-parity state, which has a lifetime (similar to 100 ps) varying with the intial photon energy. Excitation (3.1 eV) well above the exciton threshold appears to generate more slowly decaying excitons, as well as polarons that are formed upon exciton dissociation. The TA spectra also indicate that relaxation of excitons for E-pump>2 eV is mediated by large-amplitude vibrations perpendicular to the chains. Using third-harmonic generation spectroscopy in addition to TA, we develop an energy-level diagram for the excited states, including polaron levels, and the lowest odd-and even-parity excitons. C1 LOS ALAMOS NATL LAB, CHEM SCI & TECHNOL DIV, LOS ALAMOS, NM 87545 USA. SANDIA NATL LABS, DEPT 1812, ALBUQUERQUE, NM 87185 USA. UNIV ARIZONA, CTR OPT SCI, TUCSON, AZ 85721 USA. RP LOS ALAMOS NATL LAB, DIV MAT SCI, MS G755, LOS ALAMOS, NM 87545 USA. NR 45 TC 9 Z9 9 U1 0 U2 0 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 AUG 1 PY 1997 VL 56 IS 5 BP 2501 EP 2509 DI 10.1103/PhysRevB.56.2501 PG 9 WC Physics, Condensed Matter SC Physics GA XQ619 UT WOS:A1997XQ61900043 ER PT J AU Mertens, FG Schnitzer, HJ Bishop, AR AF Mertens, FG Schnitzer, HJ Bishop, AR TI Hierarchy of equations of motion for nonlinear coherent excitations applied to magnetic vortices SO PHYSICAL REVIEW B LA English DT Article ID DYNAMICS; DOMAINS; MODEL AB The shape of a solitonlike excitation in a nonintegrable system generally depends on the velocity and all higher-order time derivatives of the position (X) over right arrow of the excitation. Using a sequence of generalized traveling-wave Ansatze we derive a hierarchy of equations of motion for (X) over right arrow. The type of excitation determines on which levels the hierarchy can be truncated consistently: ''Gyrotropic'' excitations are governed by odd-order equations, nongyrotropic ones by even-order equations. Examples for the latter case are kinks in one-dimensional models and planar vortices of the two-dimensional anisotropic (easy-plane) Heisenberg model. The nonplanar vortices of this model an the simplest gyrotropic example. For this last case we solve the Hamilton equations for a finite system with one vortex and free boundary conditions and calculate the parameters of the third-order equation of motion, This equation yields trajectories which are a superposition of two cycloids with different frequencies, which is in full agreement with computer simulations of the full many-spin model. Finally we demonstrate that the additional effects from the fifth-order equation are negligible. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Mertens, FG (reprint author), UNIV BAYREUTH,INST PHYS,POB 101251,D-95440 BAYREUTH,GERMANY. NR 17 TC 50 Z9 50 U1 4 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1997 VL 56 IS 5 BP 2510 EP 2520 DI 10.1103/PhysRevB.56.2510 PG 11 WC Physics, Condensed Matter SC Physics GA XQ619 UT WOS:A1997XQ61900044 ER PT J AU Grimsditch, M Fullerton, EE Stamps, RL AF Grimsditch, M Fullerton, EE Stamps, RL TI Exchange and anisotropy effects on spin waves in epitaxial Co films SO PHYSICAL REVIEW B LA English DT Article ID BRILLOUIN-SCATTERING; MAGNETIC ANISOTROPIES; FERROMAGNETIC-FILMS; THIN-FILMS; MAGNONS; MODES AB Using Brillouin scattering we have investigated the effect of large in-plane anisotropy on magnetic excitations in b axis-oriented epitaxial 50-nm Co films. For in-plane fields along the easy axis the magnon frequencies increase monotonically with increasing field. For in-plane fields along the hard axis, nonmonotonic behavior is observed in which the surface to bulk spin-wave character of one magnon mode changes as a function of applied field. Although fits to the data based on a full theoretical treatment are consistent with parameters in the literature and with parameters extracted from the magnetization data, we show that uncertainties in crystal orientation (as small as 1 degrees) can produce dramatic effects in the quantitative data interpretation. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. RP Grimsditch, M (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Fullerton, Eric/H-8445-2013; Stamps, Robert/E-7304-2011 OI Fullerton, Eric/0000-0002-4725-9509; Stamps, Robert/0000-0003-0713-4864 NR 18 TC 22 Z9 22 U1 2 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1997 VL 56 IS 5 BP 2617 EP 2622 DI 10.1103/PhysRevB.56.2617 PG 6 WC Physics, Condensed Matter SC Physics GA XQ619 UT WOS:A1997XQ61900056 ER EF