FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Roux, P De Rosny, J Fink, M Rose, JH AF Roux, P De Rosny, J Fink, M Rose, JH TI Time-reversal mirrors and rough surfaces: Experiment SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID WAVES; WATER AB A novel acoustic time-reversal technique has been tested for determining the surface-height autocorrelation function and rms height of rough surfaces. A time-reversal mirror (TRM) was used to insonify periodically and "randomly" rough surfaces of otherwise flat samples immersed in water. The standard use of the TRM is as follows: transmit an initial planar pulse, record the signals at each array element, digitally time reverse each signal, and then retransmit the time-reversed signal. As expected from time-reversal symmetry, one approximately recovers the incident planar pulse after the reflection of the retransmitted wave. The new technique is a simple modification of this procedure. Namely, as before, we record and time reverse the initial reflection. However, we next translate the transducer a fixed distance parallel to the surface before retransmitting. For very small displacements, little change is observed in the TRM's signal. For larger and larger translations, the TRM's signal decorrelates, i.e., it less and less resembles the incident pulse. The signal's decorrelation as a function of displacement is directly related to the autocorrelation function of the rough surface-within the limits set by the system's point response function. The TRM was used both in reflection mode and in transmission mode. Samples consisted of "randomly" rough surfaces of metal and plastic plates, as well as metal plates machined to have periodically rough surfaces. Evidence is provided that the time-reversal mirror is sensitive to the surface-height autocorrelation and, in favorable cases, determines the autocorrelation function and rms height. (C) 1999 Acoustical Society of America. [S0001-4966(99)02207-9]. C1 Univ Paris 07, ESPCI, Lab Ondes & Acoust, F-75005 Paris, France. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Roux, P (reprint author), Univ Paris 07, ESPCI, Lab Ondes & Acoust, 10 Rue Vauquelin, F-75005 Paris, France. RI roux, philippe/B-8538-2014; fink, mathias/M-9437-2016; OI Fink, Mathias/0000-0002-8494-7562 NR 11 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD AUG PY 1999 VL 106 IS 2 BP 724 EP 732 DI 10.1121/1.427090 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 225YN UT WOS:000081993700021 ER PT J AU Rodriguez, MA Boyle, TJ Hernandez, BA Tallant, DR Vanheusden, K AF Rodriguez, MA Boyle, TJ Hernandez, BA Tallant, DR Vanheusden, K TI A new metastable thin-film strontium tantalate perovskite SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CRYSTAL-STRUCTURE; SRBI2TA2O9; SLABS AB A novel Sr-Ta-O perovskite phase has been synthesized by a chemical preparation route and crystallized on Pt-coated SiO2/Si substrates at similar to 800 degrees C, The phase was isolated as a thin film only (not as a polycrystalline powder) and is likely metastable, SEM, EDS, XRD, EPR, and Raman analyses suggest this phase is cation-deficient, having the formula SrxTaxO3 (x similar to 0.85). X-ray Rietveld analysis indicates the structure to be a simple-cubic perovskite-type lattice; Pm3m space group, a = 3.955(2) Angstrom, V = 61.86 Angstrom(3), Z = 1, Electrical property measurements recorded a dielectric constant k of similar to 16 with a tan delta of 0.04. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. USAF, Res Lab, Kirtland AFB, NM 87117 USA. RP Rodriguez, MA (reprint author), Sandia Natl Labs, POB 5800,MS 1405, Albuquerque, NM 87185 USA. NR 20 TC 7 Z9 7 U1 1 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 1999 VL 82 IS 8 BP 2101 EP 2105 PG 5 WC Materials Science, Ceramics SC Materials Science GA 291WZ UT WOS:000085763500022 ER PT J AU Ta, KP Newman, J AF Ta, KP Newman, J TI Proton intercalation hysteresis in charging and discharging nickel hydroxide electrodes SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID X-RAY ABSORPTION; DIFFUSION AB A reproducible hysteresis in charge-discharge cycling of thin-film (10-40 nm thickness) electroprecipitated nickel hydroxide electrodes was quantified. Thin-film electrodes were prepared both with and without coprecipitated cobalt hydroxide, a common additive to nickel hydroxide electrodes. The ascending and descending branches of the hysteretic loop were determined. Experimental data were gathered using commonly employed techniques to capture electrode behavior on short- and long-time scales. Cyclic voltammetry and galvanostatic discharge experiments were performed, and a macroscopic model of the nickel hydroxide solid material was constructed and used to interpret the simultaneous mass-transfer, kinetic, and thermodynamic phenomena occurring at the nickel hydroxide intercalation electrode. The persistent hysteresis exhibited by these thin-film electrodes cannot be due only to solid-state mass-transfer limitations. Agreement between calculated and experimental results is achieved with treatment of the hysteresis effect as a permanent, thermodynamic quantity. The numerical model may be applied to most rechargeable cells and is especially suited for systems which exhibit a permanent hysteretic loop or in which side reactions are prevalent. Model results agree with current and potential waveforms gathered from experiments performed with nickel hydroxide thin-film electrodes. (C) 1999 The Electrochemical Society. S0013-4651(98)03-044-4. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Ta, KP (reprint author), IBM Corp, San Jose, CA 95193 USA. RI Newman, John/B-8650-2008 OI Newman, John/0000-0002-9267-4525 NR 41 TC 37 Z9 37 U1 0 U2 6 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1999 VL 146 IS 8 BP 2769 EP 2779 DI 10.1149/1.1392007 PG 11 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 228EZ UT WOS:000082125300001 ER PT J AU Mansour, AN McBreen, J Melendres, CA AF Mansour, AN McBreen, J Melendres, CA TI An in situ x-ray absorption spectroscopic study of charged Li((1-z))Ni((1+z))O-2 cathode material SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID FINE-STRUCTURE SPECTRA; ELECTROCHEMICAL PROPERTIES; OXIDATION-STATE; LINIO2; NICKEL; OXYCOMPOUNDS; BEHAVIOR; XANES; CELLS; R(3)OVER-BAR-M AB We have measured in situ the Ni K-edge X-ray absorption spectra of Li(1-z)Ni(1+z)O2 cathode material charged in a nonaqueous cell. The material was charged to various states of charge (i.e., Li content) which corresponded to x = 0.0, 0.12, 0.24, 0.37, 0.49, and 0.86 in Li(1-x-z)Ni(1+z)O2. We have determined variations in the Ni-O and Ni-Ni coordination numbers, bond lengths, and local disorders as well as the Ni K-edge energies as a function of Li content. We show that in the pristine state, the composition of the material can be described by the formula Li0.86Ni1.14O2 (i.e., x = 0 and z = 0.14). That is, the material consists of Ni2+ (25%) and Ni3+ (75%) with half the Ni2+ atoms residing in Li sites and the other half in the NiO2 slabs. Upon charging, initially Ni2+ is oxidized to Ni3+ up to a state of charge which corresponds to x = 2z. Upon further charging to states corresponding to 2z < x less than or equal to 1 - z, Ni3+ is oxidized to Ni4+ with fractions being dependent on the values of x and z. Analysis of the edge energies for NiO, stoichiometric LiNiO2, and KNiIO6 as reference compounds for Ni2+, Ni3+, and Ni4+, respectively, shows a quadratic dependence for edge energy vs. oxidation state. This type of correlation is consistent with variations observed in earlier studies for some Mn reference compounds in the same range of oxidation states. Oxidation-state determination of Ni in Li(1-x-z)Ni(1+z)O2 as a function of state of charge (i.e., Li content or x) on the basis of edge energies yielded results which are in excellent agreement with oxidation state determinations made on the basis of the mole fractions for Ni2+, Ni3+, and Ni4+ extracted from extended X-ray absorption fine structure spectra. (C) 1999 The Electrochemical Society. S0013-4651(98)05-014-9. All rights reserved. C1 USN, Ctr Surface Warfare, Carderock Div, Bethesda, MD 20817 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP USN, Ctr Surface Warfare, Carderock Div, Bethesda, MD 20817 USA. NR 44 TC 47 Z9 48 U1 0 U2 10 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 EI 1945-7111 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1999 VL 146 IS 8 BP 2799 EP 2809 DI 10.1149/1.1392011 PG 11 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 228EZ UT WOS:000082125300005 ER PT J AU Zheng, F Pederson, LR AF Zheng, F Pederson, LR TI Phase behavior of lanthanum strontium manganites SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID DEFECT CHEMISTRY; LOW-TEMPERATURE; DOPED LAMNO3; FUEL-CELLS; SR; NONSTOICHIOMETRY; LA1-XSRXMNO3; ELECTRODES; REACTIVITY; LA AB The phase stability of Sr-doped LaMnO3 (LSM) perovskite in the La-Sr-Mn-O system was investigated as a function of Sr content and A/B cation ratio. The perovskite structure changed with both Sr content and A/B cation ratio. As the Sr content was increased to 0.2 mol, the perovskite structure adopted an orthorhombic distortion. This changed to a monoclinic or hexagonal structure for 0.2 less than or equal to Sr less than or equal to 0.3 mol. When the Sr content increased to 0.3 mol, the structure reverted to orthorhombic symmetry. Data from X-ray powder diffractometry, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray emission spectroscopy, showed that secondary phases in the La-Sr-Mn-O system were underdeveloped with respect to changes of the doped Sr content, A/B cation ratio, and thermal history. X-ray detectable minor phases present in the LSM material were Mn3O4, (La, Sr)Mn2O4, La2O3, La(OH)(3), (La, Sr)(3)Mn2O7, and (La, Sr)(2)MnO4. (C) 1999 The Electrochemical Society. S0013-4651(98)11-108-X. All rights reserved. C1 Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. Pacific NW Lab, Dept Chem & Mat Sci, Richland, WA 99352 USA. RP Zheng, F (reprint author), Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. NR 37 TC 50 Z9 52 U1 4 U2 18 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1999 VL 146 IS 8 BP 2810 EP 2816 DI 10.1149/1.1392012 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 228EZ UT WOS:000082125300006 ER PT J AU Zheng, F Pederson, LR AF Zheng, F Pederson, LR TI Thermodynamic properties of Sr-doped LaMnO3 perovskite in the La-Sr-Mn-O system SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CELLS; EMF; NONSTOICHIOMETRY; STABILITY AB Thermodynamic properties of Sr-doped perovskite-type lanthanum manganites (LSM) were generated by measuring the electromotive force (EMF) of rest materials, using the solid galvanic cell technique. The cell consisted of an anode (SrO/SrF2), an electrolyte (CaF2 or SrF2) and a cathode (LSM/SrF2). Two types of cells were tested in which type I used a CaF2 electrolyte and type II used a SrF2 electrolyte. The activity of SrO substituting into various LSM compositions was calculated using the measured EMF. The Sr content was varied from 0.16 to 0.6 mol, and the temperature of interest varied from 700 to 1000 degrees C. It was found that the SrO activity decreased with increasing temperature (at fixed composition) and increased with increasing Sr content (at fixed temperature). (C) 1999 The Electrochemical Society. S0013-4651(98)11-109-6. All rights reserved. C1 Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. Pacific NW Lab, Dept Chem & Mat Sci, Richland, WA 99352 USA. Washington State Univ TriCities, Richland, WA USA. RP Zheng, F (reprint author), Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. NR 36 TC 5 Z9 5 U1 0 U2 5 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1999 VL 146 IS 8 BP 2817 EP 2820 DI 10.1149/1.1392013 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 228EZ UT WOS:000082125300007 ER PT J AU Chen, XD Gibson, JM AF Chen, XD Gibson, JM TI Effect of postoxidation annealing on Si/SiO2 interface roughness SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID TRANSMISSION ELECTRON-DIFFRACTION; ATOMIC-FORCE MICROSCOPY; INCORPORATED NITROGEN; SI-SIO2 INTERFACE; SURFACE-ROUGHNESS; ION-SCATTERING; SILICON; OXIDATION; GROWTH; ELLIPSOMETRY AB We use a plan-view transmission electron microscope technique to unambiguously image the "physical" interface position between Si and furnace grown SiO2 layers. The effect of postoxidation annealing on the interface roughness of Si/SiO2 was studied with this technique. While no obvious effect due to postoxidation annealing on roughness was observed for silicon (111) a postoxidation annealing at 900 degrees C dramatically removed roughness at Si(100)/SiO2 interfaces. A model was developed to explain our experimental results based on the idea of kinetic smoothening and oxidation induced roughening. Qualitative agreement has been reached. (C) 1999 The Electrochemical Society. S0013-4651(98)05-046-0. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Chen, XD (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Gibson, Murray/E-5855-2013 OI Gibson, Murray/0000-0002-0807-6224 NR 32 TC 5 Z9 5 U1 0 U2 1 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1999 VL 146 IS 8 BP 3032 EP 3038 DI 10.1149/1.1392047 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 228EZ UT WOS:000082125300041 ER PT J AU Peskin, AM AF Peskin, AM TI Communication, technology, and politics in the information age SO JOURNAL OF URBAN TECHNOLOGY LA English DT Book Review C1 Brookhaven Natl Lab, Comp & Commun Div, Upton, NY 11973 USA. RP Peskin, AM (reprint author), Brookhaven Natl Lab, Comp & Commun Div, Upton, NY 11973 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU CARFAX PUBLISHING PI BASINGSTOKE PA RANKINE RD, BASINGSTOKE RG24 8PR, HANTS, ENGLAND SN 1063-0732 J9 J URBAN TECHNOL JI J. Urban Technol. PD AUG PY 1999 VL 6 IS 2 BP 115 EP 116 PG 2 WC Urban Studies SC Urban Studies GA 228TY UT WOS:000082152800009 ER PT J AU Miller, DL Gies, RA AF Miller, DL Gies, RA TI Consequences of lithotripter shockwave interaction with gas body contrast agent in mouse intestine SO JOURNAL OF UROLOGY LA English DT Article DE ESWL; Albunex; hemorrhage; cavitation; lithotripsy-adverse-effects ID WAVE LITHOTRIPSY; EXTRACORPOREAL LITHOTRIPSY; PIEZOELECTRIC LITHOTRIPTER; IN-VITRO; CAVITATION; HEMORRHAGE; THRESHOLDS; ULTRASOUND; FIELDS; TISSUE AB Purpose: Shockwave lithotripsy can involve complications associated with hemorrhage and internal bleeding which appear to be due to acoustic cavitation. Gas-body-based contrast agents recently developed for diagnostic ultrasound can enhance cavitational bioeffects under some conditions. This study examined the occurrence and progression of vascular damage in mouse intestine when a contrast agent was present during shockwave treatment. Materials and Methods: Anesthetized hairless mice were injected with Albunex(R) contrast agent or a gas-body-free blank, and exposed to sham, 200 or 800 lithotripter shockwaves. Results: Exposure of the mouse abdomen to lithotripter shockwaves produced petechiae in the intestinal wall and hemorrhage into the lumen. Contrast-agent gas bodies greatly enhanced the numbers of petechiae (but not the hemorrhages), relative to the blank agent. When evaluation of these effects was delayed for one day, both effects decreased, and the gas-body-associated petechiae seemed to disappear. However, survival significantly decreased for mice with added gas bodies and shockwave treatment. Conclusions: The presence of a gas-body-based ultrasound contrast agent enhances vascular side effects of shockwave lithotripsy. Although there are great uncertainties in relating these observations to human clinical conditions, a delay in planned treatment might be prudent for patients scheduled for shockwave lithotripsy soon after receiving gas-body-based ultrasound contrast agents. C1 Univ Michigan, Dept Radiol, Ann Arbor, MI 48109 USA. Battelle Paicific NW Natl Lab, Richland, WA USA. RP Miller, DL (reprint author), Univ Michigan, Dept Radiol, Ann Arbor, MI 48109 USA. FU NCI NIH HHS [CA42947] NR 20 TC 14 Z9 14 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0022-5347 J9 J UROLOGY JI J. Urol. PD AUG PY 1999 VL 162 IS 2 BP 606 EP 609 DI 10.1016/S0022-5347(05)68634-X PG 4 WC Urology & Nephrology SC Urology & Nephrology GA 214UA UT WOS:000081344900095 PM 10411095 ER PT J AU Vogt, VM Simon, MN AF Vogt, VM Simon, MN TI Mass determination of Rous sarcoma virus virions by scanning transmission electron microscopy SO JOURNAL OF VIROLOGY LA English DT Article ID AVIAN-MYELOBLASTOSIS VIRUS; CYCLOPHILIN-A; GAG PROTEIN; RETROVIRAL VECTORS; LEUKEMIA VIRUSES; HIV-1 VIRIONS; PARTICLE-SIZE; IN-VITRO; TYPE-1; GENE AB The internal structural protein of retroviruses, Gag, comprises most of the mass of the virion, and Gag itself can give rise to virus-like particles when expressed in appropriate cells. Previously the stoichiometry of Gag in virions was inferred from indirect measurements carried out 2 decades ago. We now have directly determined the masses of individual particles of the prototypic avian retrovirus, Rous sarcoma virus (RSV), by using scanning transmission electron microscopy. In this technique, the number of scattered electrons in the dark-field image integrated over an individual freeze-dried virus particle on a grid is directly proportional to its mass. The RSV virions had a mean mass of 2.5 x 10(8) Da, corresponding to about 1,500 Gag molecules per virion. The population of virions was not homogeneous, dth about one-third to two-thirds of the virions deviating from the mean by more than 10% of the mass in two respective preparations. The mean masses for virions carrying genomes of 7.4 or 9.3 kb were indistinguishable, suggesting that mass variability is not due to differences in RNA incorporation. C1 Cornell Univ, Dept Mol Biol & Genet, Sect Mol Biol & Genet, Ithaca, NY 14853 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Vogt, VM (reprint author), Cornell Univ, Dept Mol Biol & Genet, Sect Mol Biol & Genet, Biotechnol Bldg, Ithaca, NY 14853 USA. FU NCI NIH HHS [CA20081, R01 CA020081]; NCRR NIH HHS [P41-RR01777, P41 RR001777] NR 45 TC 95 Z9 95 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0022-538X J9 J VIROL JI J. Virol. PD AUG PY 1999 VL 73 IS 8 BP 7050 EP 7055 PG 6 WC Virology SC Virology GA 215HZ UT WOS:000081377400099 PM 10400808 ER PT J AU Di Vito, MA Isaia, R Orsi, G Southon, J de Vita, S D'Antonio, M Pappalardo, L Piochi, M AF Di Vito, MA Isaia, R Orsi, G Southon, J de Vita, S D'Antonio, M Pappalardo, L Piochi, M TI Volcanism and deformation since 12,000 years at the Campi Flegrei caldera (Italy) SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Campi Flegrei caldera; volcanism; deformation; chronostratigraphy ID TUFF AB The Campi Flegrei caldera is a restless, nested structure resulting from two major collapses related to the Campanian Ignimbrite (37,000 years BP) and the Neapolitan Yellow Tuff (12,000 years BP) eruptions, respectively. Detailed stratigraphical, structural, volcanological and C-14 (AMS) geochronological studies, devoted to the reconstruction of the volcanic and deformational history of the Campi Flegrei caldera in the past 12,000 years have been carried out. The results of these studies show that in this time span, intense both volcanic and volcano-tectonic activity was confined inside the Neapolitan Yellow Tuff caldera. Volcanism was concentrated in epochs of intense activity, alternating to periods of quiescence. The I epoch lasted from 12,000 to 9500 years BP giving rise to 34 explosive eruptions, each every 70 years on average. During the II epoch, dated between 8600 and 8200 years BP, six explosive eruptions took place at an average interval of 65 years. The III epoch lasted from 4800 to 3800 years BP and produced 16 explosive and four effusive eruptions which followed each other at mean intervals of 50 years. Eruption vents of the I epoch were located mostly along the marginal faults of the Neapolitan Yellow Tuff caldera, while those of the II epoch aligned on the northeastern sector of this margin. During the LII epoch volcanism was confined in the northeastern sector of the Neapolitan Yellow Tuff caldera floor. The caldera floor is disjointed in blocks with variable vertical movements by fault and fracture systems mainly trending NE-SW and NW-SE. The still active resurgence of the caldera floor began soon after its collapse. Onset of bath II and III epoch of activity coincides with increase in resurgence rate of La Starza marine terrace, the most uplifted part of the resurgent block. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Osservatorio Vesuviano, I-80123 Naples, Italy. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Dipartimento Geofis & Vulcanol, I-80138 Naples, Italy. RP Di Vito, MA (reprint author), Osservatorio Vesuviano, Via Manzoni 249, I-80123 Naples, Italy. RI de Vita, Sandro/G-5974-2011; D'Antonio, Massimo/C-5199-2012 OI D'Antonio, Massimo/0000-0003-2077-943X NR 34 TC 241 Z9 241 U1 3 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD AUG PY 1999 VL 91 IS 2-4 BP 221 EP 246 DI 10.1016/S0377-0273(99)00037-2 PG 26 WC Geosciences, Multidisciplinary SC Geology GA 256HH UT WOS:000083719500007 ER PT J AU de Vita, S Orsi, G Civetta, L Carandente, A D'Antonio, M Deino, A di Cesare, T Di Vito, MA Fisher, RV Isaia, R Marotta, E Necco, A Ort, M Pappalardo, L Piochi, M Southon, J AF de Vita, S Orsi, G Civetta, L Carandente, A D'Antonio, M Deino, A di Cesare, T Di Vito, MA Fisher, RV Isaia, R Marotta, E Necco, A Ort, M Pappalardo, L Piochi, M Southon, J TI The Agnano-Monte Spina eruption (4100 years BP) in the restless Campi Flegrei caldera (Italy) SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Agnano-Monte Spina tephra; Campi Flegrei caldera; magma; pyroclastic-fallout; pumice ID STRUCTURAL EVOLUTION; PHLEGRAEAN FIELDS; CHAMBER; HISTORY; SERIES; KENYA AB The Agnano-Monte Spina tephra (AMST), dated at 4100 years BP by Ar-40/Ar-39 and C-14 AMS techniques, is the product of the highest-magnitude eruption in the Campi Flegrei caldera (CFc) during its last epoch of activity (4800-3800 years BP). The sequence alternates magmatic and phreatomagmatic pyroclastic-fallout, -flow and -surge beds and bedsets. Two main pumice-fallout deposits with variable easterly-to-northeasterly dispersal axes are about 10 cm thick at 42 km from the vent area. High particle concentration pyroclastic currents were confined to the caldera depression; lower concentration flows overtopped the morphological boundary of the caldera and traveled at least 15 km over the surrounding plain. The unit is subdivided into six members, named A through F in stratigraphic sequence, based upon their sedimentological characteristics. Isopachs and isopleths maps suggest a vent location in the Agnano plain. A volcano-tectonic collapse begun during the course of the eruption, took place along the faults of the northeastern sector of the resurgent block within the CFc. and generated the Agnano plain. The early erupted trachytic magma had a homogeneous alkali-trachytic composition, whereas later-erupted magma shows small-scale hetereogeneities. Trace elements and Sr-isotope compositions, indicate that two isotopically distinct magmas, one alkali-trachytic and the other trachytic, were tapped and partially mixed during the eruption. The small volume (1.2 km(3) DRE) of erupted magma and the structural position of the vent suggest that the eruption was fed by a dyke intruded along a normal fault in the sector of the resurgent block under a tensional stress regime. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Osservatorio Vesuviano, I-80056 Naples, Italy. Dipartimento Geofis & Vulcanol, I-80138 Naples, Italy. Univ Calif Santa Barbara, Dept Geol Sci, Santa Barbara, CA 93106 USA. No Arizona Univ, Dept Environm Sci & Geol, Flagstaff, AZ 86011 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Inst Human Origins, Berkeley, CA USA. RP de Vita, S (reprint author), Osservatorio Vesuviano, I-80056 Naples, Italy. RI de Vita, Sandro/G-5974-2011; D'Antonio, Massimo/C-5199-2012; OI D'Antonio, Massimo/0000-0003-2077-943X; CARANDENTE, Antonio/0000-0001-6198-6326 NR 40 TC 125 Z9 125 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD AUG PY 1999 VL 91 IS 2-4 BP 269 EP 301 DI 10.1016/S0377-0273(99)00039-6 PG 33 WC Geosciences, Multidisciplinary SC Geology GA 256HH UT WOS:000083719500009 ER PT J AU Wohletz, K Civetta, L Orsi, G AF Wohletz, K Civetta, L Orsi, G TI Thermal evolution of the Phlegraean magmatic system SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Campi Flegrei caldera; Phlegraean magmatic system; Campanian Ignimbrite ID CAMPI-FLEGREI CALDERA; NEAPOLITAN-YELLOW-TUFF; STRUCTURAL EVOLUTION; CAMPANIAN IGNIMBRITE; ERUPTIVE MECHANISMS; GROUND MOVEMENT; TRACE-ELEMENT; FIELDS; CHAMBER; HISTORY AB A series of 2-D conductive/convective numerical models show a rather limited range of possible magma chamber configurations that predict the present thermal regime at Campi Flegrei. These models are calculated by HEAT, which allows continuous adjustment of heterogeneous rock properties, magma injection/replenishment, and convective regimes. The basic test of each model is how well it reproduces the measured thermal gradients in boreholes at Licola, San Vito, and Mofete reported by AGIP in 1987. The initial and boundary conditions for each model consists of a general crustal structure determined by geology and geophysics and major magmatic events: (1) the 37 ka Campanian Ignimbrite; (2) smaller volume 37-16 ka eruptions; (3) the 12 ka Neapolitan Yellow Tuff; (4) recent magmatism (e.g., Minopoli at similar to 10 ka and Monte Nuovo in 1538 AD). While magma chamber depth is well constrained, magma chamber diameter, shape, volume, and peripheral convective regimes are poorly known. Magma chamber volumes between 200 and 2000 km(3) have been investigated with cylindrical, conical (funnel-shaped), and spheroidal shapes. For all reasonable models, a convective zone, developed above the magma chambers after caldera collapse, is necessary to achieve the high gradients seen today. These models should help us understand recent bradyseismic events and future unrest. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Naples Federico II, Dipartimento Geofis & Vulcanol, Naples, Italy. RP Wohletz, K (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 80 TC 74 Z9 76 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD AUG PY 1999 VL 91 IS 2-4 BP 381 EP 414 DI 10.1016/S0377-0273(99)00048-7 PG 34 WC Geosciences, Multidisciplinary SC Geology GA 256HH UT WOS:000083719500015 ER PT J AU Orsi, G Petrazzuoli, SM Wohletz, K AF Orsi, G Petrazzuoli, SM Wohletz, K TI Mechanical and thermo-fluid behaviour during unrest at the Campi Flegrei caldera (Italy) SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Campi Flegrei caldera; Italy; ground deformation; seismicity ID NEAPOLITAN-YELLOW-TUFF; LONG-VALLEY CALDERA; SURFACE DEFORMATION; MAGMA CHAMBER; GROUND DEFORMATION; ERUPTIVE DYNAMICS; KILAUEA VOLCANO; HALF-SPACE; EVOLUTION; COLLAPSE AB The Campi Flegrei caldera (CFc) is a resurgent, nested structure resulting from the two main collapses of the Campanian Ignimbrite (37 ka) and the Neapolitan Yellow Tuff (12 ka) eruptions. While the whole structure is affected by a broad subsidence, ongoing local resurgence and unrest occur inside the young, nested caldera structure. The caldera has shown signs of unrest during the past 30 years, with two uplift events that have generated a net displacement of 3.5 m, each followed by subsidence. The time evolution of both ground deformation and seismicity recorded in Campi Flegrei in the last 30 years (since 1969 up to the present) shows aspects not completely explainable by means of mechanical models. In particular, the occurrence of an intense seismic activity during uplift and its absence during subsidence lead us to infer that these two phases might be related to two variable mechanisms. The large amount of magma and the shallow convective fluids circulation needed to explain the very high temperature gradient (100 degrees C/km) measured also in marginal areas of the caldera, suggest the presence of a thermo-dynamical system in supercritical conditions. We have carried out an analysis of the unrest episodes by means of 3D finite-element method, simulating the mechanical and fluid-dynamical response of a two phase medium (solid-fluid) to a sudden (stepwise) pressure or volume increase at a depth of 4 km. According to geological and geophysical constraints, in our scheme we have subdivided the caldera floor into a central and a peripheral zone. The central zone represents the resurgent block and has high permeability, while the peripheral zone is less permeable. We have performed a parametric analysis assuming both Young modulus and permeability of each zone as variables. The basic test for each solution was how well it simulates the time evolution of ground deformation during the last unrest episode (1982-1984). The results obtained clearly show that fluids diffusion accounts for some peculiar features of the ground deformation such as the variable behavior between the resurgent block and the peripheral part of the caldera floor. Subsidence is explained in terms of lateral diffusion of fluids instead of a regression of source processes. Consequently, no variation of shear stress occurs during this phase, providing a physical explanation to the absence of seismicity. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Osservatorio Vesuviano, I-80123 Naples, Italy. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Orsi, G (reprint author), Osservatorio Vesuviano, Via Manzoni 249, I-80123 Naples, Italy. NR 45 TC 44 Z9 44 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD AUG PY 1999 VL 91 IS 2-4 BP 453 EP 470 DI 10.1016/S0377-0273(99)00051-7 PG 18 WC Geosciences, Multidisciplinary SC Geology GA 256HH UT WOS:000083719500017 ER PT J AU Sammi, MK Felder, CA Fowler, JS Lee, JH Levy, AV Li, X Logan, T Palyka, I Rooney, WD Volkow, ND Wang, GT Springer, CS AF Sammi, MK Felder, CA Fowler, JS Lee, JH Levy, AV Li, X Logan, T Palyka, I Rooney, WD Volkow, ND Wang, GT Springer, CS TI Intimate combination of low- and high-resolution image data: I. Real-space PET and (H2O)-H-1 MRI, PETAMRI SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article ID MAGNETIC-RESONANCE IMAGES; BRAIN GLUCOSE-METABOLISM; DOPAMINE D-2 RECEPTORS; WHITE-MATTER; GRAY-MATTER; SEGMENTATION; DISPLAY; REGISTRATION; RELAXATION; ALGORITHM AB Two different types of (co-registered) images of the same slice of tissue will generally have different spatial resolutions, The judicious pixel-by-pixel combination of their data can be accomplished to yield a single image exhibiting properties of both. Here, axial (18)FDG PET and (H2O)-H-1 MR images of the human brain are used as the low- and high-resolution members of the pair. A color scale is necessary in order to provide for separate intensity parameters from the two image types. However, not all color scales can accommodate this separability. The HSV color model allows one to choose a color scale in which the intensity of the low-resolution image type is coded as hue, while that of the high-resolution type is coded as value, a reasonably independent parameter. Furthermore, the high-resolution image must have high contrast and be quantitative in the same sense as the low-resolution image almost always is. Here, relaxographic MR images (naturally segmented quantitative (H2O)-H-1 spin-density components) are used. Their essentially complete contrast serves to effect an apparent editing function when encoded as the value of the color scale. Thus, the combination of 1(8F)DG PET images with gray-matter (GM) relaxographic (H2O)-H-1 images produces visually "GM-edited" (18)FDG PETAMR (positron emission tomography and magnetic resonance) images, These exhibit the high sensitivity to tracer amounts characteristic of PET along with the high spatial resolution of (H2O)-H-1 MRI, At the same time, however, they retain the complete quantitative measures of each of their basis images. Magn Reson Med 42:345-360, 1999. Published 1999 Wiley-Liss, Inc.dagger C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Springer, CS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Lee, Jing-Huei/J-3978-2016; OI Lee, Jing-Huei/0000-0001-9921-7629; Springer, Charles/0000-0002-5966-2135 FU NIGMS NIH HHS [R01-GM32125-15] NR 42 TC 12 Z9 13 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn. Reson. Med. PD AUG PY 1999 VL 42 IS 2 BP 345 EP 360 DI 10.1002/(SICI)1522-2594(199908)42:2<345::AID-MRM17>3.0.CO;2-E PG 16 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 221ZQ UT WOS:000081758100017 PM 10440960 ER PT J AU Valette-Silver, N Hameedi, MJ Efurd, DW Robertson, A AF Valette-Silver, N Hameedi, MJ Efurd, DW Robertson, A TI Status of the contamination in sediments and biota from the western Beaufort Sea (Alaska) SO MARINE POLLUTION BULLETIN LA English DT Review ID POLYCYCLIC AROMATIC-HYDROCARBONS; SPILL EXPERIMENTAL SITES; BAFFIN ISLAND; UNITED-STATES; TRACE-METALS; CHEMICAL CONCENTRATIONS; CONTINENTAL-SHELF; STRATHCONA SOUND; ARCTIC COD; ESTUARINE AB Surficial sediments in the western Beaufort Sea contained generally high concentrations of arsenic (up to 58 ppm as corrected for grain size), very low amounts of organochlorine compounds and concentrations of total polycyclic aromatic hydrocarbons (PAHs) ranging from similar to 160 to 1100 ng/dry weight. Invertebrates contained higher concentrations of total PAHs than fish, with naphthalene being the largest contributor. Diagnostic ratios of various PAH compounds in our samples do not suggest crude oil as the main source of PAHs, Other sources of PAHs to the region include rivers outflow, coastline erosion, oil seeps, diagenesis, and long-range atmospheric transport. Organochlorine contaminants were consistently found in our samples at concentrations generally lower than those found in other parts of the United States, (137)Cesium (Cs) was found in measurable amounts in all sediments and biota samples. Isotopic ratios showed that radionuclides originated most likely from global fallout. Compared to other coastal areas off Alaska, the Arctic, and the conterminous United States, Beaufort Sea contamination appears generally low. Published by Elsevier Science Ltd. C1 NOAA, Silver Spring, MD 20910 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP NOAA, N-ORCA2,1305 EW Highway, Silver Spring, MD 20910 USA. NR 152 TC 28 Z9 32 U1 4 U2 14 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD AUG PY 1999 VL 38 IS 8 BP 702 EP 722 DI 10.1016/S0025-326X(99)00034-X PG 21 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 237ZL UT WOS:000082686400020 ER PT J AU Louthan, MR AF Louthan, MR TI Untitled - Preface SO MATERIALS CHARACTERIZATION LA English DT Editorial Material C1 Savannah River Technol Ctr, Aiken, SC 29801 USA. RP Louthan, MR (reprint author), Savannah River Technol Ctr, Aiken, SC 29801 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 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-SEP PY 1999 VL 43 IS 2-3 BP 71 EP 71 DI 10.1016/S1044-5803(99)00062-5 PG 1 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400001 ER PT J AU Cappiello, M Pitcher, E AF Cappiello, M Pitcher, E TI Design and operation of the APT Target/Blanket SO MATERIALS CHARACTERIZATION LA English DT Article AB The Accelerator Production of Tritium (APT) Target/Blanket (T/B) system is comprised of the T/B assembly and the attendant heat-removal systems. The T/B assembly produces tritium using a high-energy proton beam and a spallation neutron source. All systems reside within the T/B building, located at the end of a linear accelerator. During nominal operation, protons are accelerated to an energy of 1030MeV at a current of 100mA. The protons interact with tungsten and lead nuclei in the T/B assembly to produce neutrons through the process of nuclear spallation. Neutron capture in He-3 gas produces tritium, which is removed on a semicontinuous basis. The T/B assembly is modular, to allow for replacement of spent components and minimization of waste. Inconel and Aluminum structural materials provide containment of spallation products, a coolant pressure boundary, and corrosion resistance. The operating environment is a combination of high-energy protons and neutrons. All structures operate at low temperature and are cooled with water. Structures directly in the proton beam, which endure the highest irradiation damage, are replaced annually. Materials in the blanket region are primarily in a low-neutron flux environment and potentially will last the life of the facility. Published by Elsevier Science Inc. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Cappiello, M (reprint author), Univ Calif Los Alamos Natl Lab, MS H016, Los Alamos, NM 87545 USA. NR 3 TC 10 Z9 10 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-SEP PY 1999 VL 43 IS 2-3 BP 73 EP 82 DI 10.1016/S1044-5803(99)00028-5 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400002 ER PT J AU Fisher, DL AF Fisher, DL TI APT target blanket module fabrication and characterization of prototypical assemblies SO MATERIALS CHARACTERIZATION LA English DT Article AB Practical aspects of producing tritium with a linear accelerator were studied recently as part of the U.S. Department of Energy's Accelerator Production of Tritium program. The concept uses the neutrons produced by an energetic accelerator beam striking target material, to convert He-3 gas to tritium. Design requirements for the medullar assemblies that surround the target posed some challenges in fabrication. Small-scale modules fabricated for accelerator tests were followed by production-scale modules, built to identify preferred fabrication and assembly processes. Casting, used successfully in the small modules, displayed distinct disadvantages with production-scale parts, and was replaced by extrusion. Machining and welding were minimized, extrusion was incorporated for lead cores and aluminum housings, and the modules were assembled manually. Two prototypical production-scale blanket modules and one tritium production module were fabricated to demonstrate the recommended techniques. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Inc. All rights reserved. C1 Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Fisher, DL (reprint author), Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 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-SEP PY 1999 VL 43 IS 2-3 BP 83 EP 95 DI 10.1016/S1044-5803(99)00029-7 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400003 ER PT J AU Sommer, W Werbeck, R Maloy, S Borden, M Brown, R AF Sommer, W Werbeck, R Maloy, S Borden, M Brown, R TI Materials selection and qualification processes at a high-power spallation neutron source SO MATERIALS CHARACTERIZATION LA English DT Article AB The accelerator at the Los Alamos Neutron Science Center (LANSCE) at the Los Alamos National Laboratory has been in operation since 1972. Development of materials for service in high voltage applications, high-vacuum systems, magnetic and electric fields, high particle radiation fluxes, and corrosive atmospheres has been ongoing during this period. Materials were initially selected based on performance at other facilities and at fission reactors. Modification to materials selection and specifications were made based on experience at LANSCE. Plans for higher power accelerators, such as the one proposed for the Accelerator Production of Tritium Project, have led to a realization that dedicated materials radiation damage effects studies are necessary to ensure adequate service lifetimes and to allow planning for preventative maintenance. Published by Elsevier Science Inc. C1 Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Tech Project Off, Los Alamos, NM 87545 USA. RP Sommer, W (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, POB 1663, Los Alamos, NM 87545 USA. NR 38 TC 5 Z9 5 U1 0 U2 2 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-SEP PY 1999 VL 43 IS 2-3 BP 97 EP 123 DI 10.1016/S1044-5803(99)00041-8 PG 27 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400004 ER PT J AU Chandler, GT Iyer, NC Louthan, MR AF Chandler, GT Iyer, NC Louthan, MR TI Water chemistry control for the target/blanket region of the Accelerator Production of Tritium SO MATERIALS CHARACTERIZATION LA English DT Article AB High-energy particle interactions in the various components of the target/blanket region of the Accelerator Production of Tritium lead to heat generation and deposition Heavy-water and light-water systems are used to cool the target/blanket system and associated equipment. Structural materials include Inconel alloy 718, aluminum-clad lead rods, aluminum tubes containing helium-3 and tritium gas, and stainless steel components. Proper coolant chemistry is required to maximize neutron production, minimize corrosion of components, and minimize activity buildup. Corrosion-related phenomena and development of coolant and moderator corrosion control for both power and defense fission reactors has been studied extensively over the past 50 years. Less is known, however, about cooling systems for accelerators where a variety of transient chemical species and spallation products may be formed. The following provides a discussion on the issues that need to be addressed for proper water chemistry control for the APT system. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Inc. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Chandler, GT (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 25 TC 1 Z9 1 U1 0 U2 1 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-SEP PY 1999 VL 43 IS 2-3 BP 125 EP 134 DI 10.1016/S1044-5803(99)00033-9 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400005 ER PT J AU Lillard, RS Butt, DP AF Lillard, RS Butt, DP TI A method for measuring the corrosion rate of materials in spallation neutron source target/blanket cooling loops SO MATERIALS CHARACTERIZATION LA English DT Article ID BOILING WATER-REACTOR; STAINLESS; CHEMISTRY; HYDROGEN; STEELS AB This paper summarizes the ongoing evaluation of the susceptibility of materials in accelerator target/blanket cooling loops to corrosion. To simulate the exposure environment in a target/blanket cooling loop, samples were irradiated by an 800MeV proton beam at the A6 Target Station of the Los Alamos Neutron Science Center (LANSCE). To accomplish this, a cooling water loop capable of exposing corrosion samples to an 800MeV proton beam at currents upwards of 1 mA was constructed. This loop allowed control and evaluation hydrogen water chemistry, water conductivity, and solution pH. Specially designed ceramic sealed samples were used to measure the real-time corrosion rates of materials placed directly in the proton beam using electrochemical impedance spectroscopy (EIS). EIS was also used to measure real-time corrosion rates of samples that were out of the proton beam and "downstream" from the in-beam samples. These out-of-beam probes primarily examined the effects of long lived water radiolysis products from proton irradiation on corrosion rates. An overview of the LANSCE corrosion loop, the corrosion probes, and data from an in-beam alloy 718 probe are presented. Published by Elsevier Science Inc. C1 Univ Calif Los Alamos Natl Lab, Mat Corros & Environm Effects Lab, Met Grp, Los Alamos, NM 87545 USA. RP Lillard, RS (reprint author), Univ Calif Los Alamos Natl Lab, Mat Corros & Environm Effects Lab, Met Grp, MST-6, Los Alamos, NM 87545 USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 28 TC 8 Z9 8 U1 0 U2 3 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-SEP PY 1999 VL 43 IS 2-3 BP 135 EP 145 DI 10.1016/S1044-5803(99)00030-3 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400006 ER PT J AU Sindelar, RL Lam, PS Louthan, MR Iyer, NC AF Sindelar, RL Lam, PS Louthan, MR Iyer, NC TI Corrosion of metals and alloys in high radiation fields SO MATERIALS CHARACTERIZATION LA English DT Article ID DESIGN; PHYSICS AB Degradation in the properties of structural materials in high-energy proton accelerators will occur as a result of the radiation environment during routine accelerator operations.. The potential for such degradation must be included in design and service life assessments of the materials and components. Structural materials in the window, target/blanket, and reflector regions of high-energy proton accelerators will be exposed to a mixed proton-neutron flux that will change the material's exposure environment and cause displacement damage and implant spallation products in the exposed metal. The effects of implantation and displacement damage on materials behavior have been studied on a more or less continuous basis for decades, while radiation effects on corrosion and corrosion related degradation processes has received relatively little attention. The high radiation fields will accelerate corrosion, enhance hydrogen uptake and permeation, and promote corrosion fatigue through environmental changes induced by radiolysis and the deposition of spallation products. Aluminum alloys are particularly susceptible to radiation-induced acceleration of corrosion, and may experience a decreased resistance to fatigue damage. The irradiation fields and the (n, p) reactions associated with tritium production will enhance the uptake and permeation of tritium through austenitic stainless. These radiation-induced effects must be considered in any realistic assessment of material performance in the APT target/blanket region. This paper rationalizes the impact of high radiation fields on corrosion, hydrogen embrittlement, and corrosion fatigue, and relates that impact to radiation-induced changes in chemical reactivity, hydrogen fugacity, and surface chemistry. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Inc. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Sindelar, RL (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 13 TC 6 Z9 6 U1 0 U2 14 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-SEP PY 1999 VL 43 IS 2-3 BP 147 EP 157 DI 10.1016/S1044-5803(99)00042-X PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400007 ER PT J AU Snead, CL Hanson, A Greene, GA Ghosh, A Czajkowski, CJ Chan, KCD Ward, TE Safa, H AF Snead, CL Hanson, A Greene, GA Ghosh, A Czajkowski, CJ Chan, KCD Ward, TE Safa, H TI Resistivity changes in superconducting cavity-grade Nb following high-energy proton irradiation SO MATERIALS CHARACTERIZATION LA English DT Article AB Niobium superconducting rf cavities are proposed for use in the proton LINAC accelerators for spallation-neutron applications. The potential for accidental beam loss and continual halo losses along the accelerator path cause concern for the degradation of the superconducting properties of the cavities with accumulating damage. Residual-resistivity-ratio (RRR) specimens of Nb, with a range of initial RRRs, were irradiated at room temperature with protons at energies from 200 to 2000MeV. Four-probe resistance measurements were made at room temperature and at 4.2K, both prior to and after irradiation. Nonlinear increases in resistivity simulate expected behavior in cavity material after extended irradiation, followed by periodic anneals to room temperature. Irradiations to 2-3 x 10(15)p/cm(2) produce degradations up to the 10% level in materials that had a RRR = 316. Such a change is deemed operationally acceptable for an rf cavity. However, without periodic warming to room temperature, the accumulated damage energy would be up to a factor of greater than ten, resulting in unacceptable degradations. Likewise, the same damage energy imparted to higher RRR material would cause larger percentage changes in the RRR. Published by Elsevier Science Inc. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Dept Energy, Washington, DC USA. SEA Saclay, Gif Sur Yvette, France. RP Snead, CL (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 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-SEP PY 1999 VL 43 IS 2-3 BP 159 EP 167 DI 10.1016/S1044-5803(99)00037-6 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400008 ER PT J AU Cowgill, DF Causey, RA AF Cowgill, DF Causey, RA TI Tritium retention and permeation through aluminum APT tubes SO MATERIALS CHARACTERIZATION LA English DT Article ID DEUTERIUM AB Tritium retention in the walls of the He-3 tubes caused by energetic He-3(n,p)H-3 triton flux is examined by accelerator-based implantation experiments. Retention, measured by post-implantation thermodesorption, is separated into a mobile, permeating and a trapped, near-surface concentration. The mobile fraction is observed to saturate at about 10appm, while the trapped fraction increases linearly with fluence with a retention fraction of 30% until surface blistering occurs. The consequences of this tritium permeation and inventory to APT and potential methods to reduce these quantities are discussed. Published by Elsevier Science Inc. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Cowgill, DF (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 14 TC 4 Z9 4 U1 0 U2 0 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-SEP PY 1999 VL 43 IS 2-3 BP 169 EP 178 DI 10.1016/S1044-5803(99)00031-5 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400009 ER PT J AU Louthan, MR Iyer, NC Morgan, MJ AF Louthan, MR Iyer, NC Morgan, MJ TI Helium/hydrogen effects on the properties of materials for the APT target/blanket region SO MATERIALS CHARACTERIZATION LA English DT Article ID HELIUM AB Materials irradiated in the target/blanket region of the Accelerator Production of Tritium (APT) system will contain significantly more hydrogen and helium, for any given displacements per atom (dpa), than typically found in materials irradiated in a fission reactor. The individual effects of helium and hydrogen implantation and displacement damage on structural materials are relatively well established. Helium will increase the strength, decrease the ductility, reduce the creep and stress rupture properties, decrease the fatigue life and weldability, and promote swelling. Hydrogen will also adversely effect the mechanical properties and promote premature fracture along metallurgical interfaces. Displacement damage generally increases the strength and decreases the ductility of single-phase metals and alloys. The adverse effects of hydrogen and helium implantation may couple with displacement damage to limit component lifetime in the target/blanket region of the APT system. This paper provides a technical basis to rationalize potential synergistic effects among displacement damage and the hydrogen and helium embrittlement processes and suggests that such synergistic effects may be of significant importance to component performance in intense spallation neutron sources. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Inc. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29801 USA. RP Louthan, MR (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29801 USA. NR 14 TC 3 Z9 3 U1 0 U2 2 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-SEP PY 1999 VL 43 IS 2-3 BP 179 EP 186 DI 10.1016/S1044-5803(99)00034-0 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400010 ER PT J AU Czajkowski, CJ Usmani, S Greene, GA AF Czajkowski, CJ Usmani, S Greene, GA TI Effects of mercury on thermally sprayed aluminum coatings SO MATERIALS CHARACTERIZATION LA English DT Article AB The quantification of liquid metal embrittling effects of mercury on thermally sprayed aluminum was investigated. The program consisted of heat treatments at 250 and 300 degrees C of thermally sprayed (aluminum on lead) cylinders with mercury additions of 0.25, 0.50, 1.00, and 3.00wt.%. The cylinders were then tested to determine the adhesion/cohesion strength of the thermally sprayed bond. The Pb/Al interfaces were evaluated using energy dispersive spectroscopy (EDS). The results of the testing indicate that there was no noticeable embrittling effects of the mercury, up to 3.0wt.% Hg in the Pb matrix. Published by Elsevier Science Inc. C1 Brookhaven Natl Lab, Dept Adv Technol, Upton, NY 11973 USA. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Czajkowski, CJ (reprint author), Brookhaven Natl Lab, Dept Adv Technol, Upton, NY 11973 USA. NR 3 TC 1 Z9 1 U1 0 U2 2 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-SEP PY 1999 VL 43 IS 2-3 BP 187 EP 194 DI 10.1016/S1044-5803(99)00036-4 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400011 ER PT J AU Usmani, S Czajkowski, CJ Zatorski, R AF Usmani, S Czajkowski, CJ Zatorski, R TI Thermally sprayed coatings: Aluminum on lead SO MATERIALS CHARACTERIZATION LA English DT Article AB An experimental program to determine the feasibility of thermally spraying aluminum on a lead substrate was initiated in support of the accelerator production of tritium (APT) Project for the U.S. Department of Energy. The program consisted of two distinct parts: (1) the characterization of the thermally sprayed coatings,including microhardness testing, effects of heating, and microstructure and porosity determinations, and (2) effects of mercury doping and heat treatments on the thermally sprayed composite. The project determined that aluminum could successfully be thermally sprayed onto the lead. The coatings had a dense microstructure, with a Vicker's Pyramid Hardness (VPH) of about 60, and a maximum porosity (found in strips on the samples) of 12%. Published by Elsevier Science Inc. C1 SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Adv Technol, Upton, NY 11973 USA. Zatorski Coatings Co, E Hampton, CT USA. RP Usmani, S (reprint author), SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 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-SEP PY 1999 VL 43 IS 2-3 BP 195 EP 202 DI 10.1016/S1044-5803(99)00035-2 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400012 ER PT J AU Kanne, WR Louthan, MR Rankin, DT Tosten, MH AF Kanne, WR Louthan, MR Rankin, DT Tosten, MH TI Weld repair of irradiated materials SO MATERIALS CHARACTERIZATION LA English DT Article ID REMOTE REACTOR REPAIR; STAINLESS-STEEL; HELIUM; CRACKING AB Maintenance of an accelerator for production of tritium will require replacement or modification of components that have been exposed to neutron irradiation. A primary repair option is welding, but conventional repair welding processes produced severe cracking in irradiated stainless steel. Optical metallography, scanning electron microscopy, and transmission electron microscopy have shown that the cracks are: intergranular, primarily in the weld heat-affected zone, characterized by a dimple structure on the crack surface, and associated with helium bubbles that grow during welding. A model has been developed that qualitatively shows the interaction of three primary and three secondary variables producing helium embrittlement cracking. A shallow penetration overlay technique was successfully demonstrated to minimize cracking in irradiated 304 stainless steel that contained 10appm helium. The overlay technique provides a potential method for repair or modification of accelerator materials exposed to irradiation. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Inc. All rights reserved. C1 Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Kanne, WR (reprint author), Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 9 TC 5 Z9 5 U1 1 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-SEP PY 1999 VL 43 IS 2-3 BP 203 EP 214 DI 10.1016/S1044-5803(99)00032-7 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 263VF UT WOS:000084145400013 ER PT J AU Anderson, AJ Thompson, RB Cook, CS AF Anderson, AJ Thompson, RB Cook, CS TI Ultrasonic measurement of the Kearns texture factors in zircaloy, zirconium, and titanium SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID ELECTROMAGNETIC ACOUSTIC TRANSDUCERS; PLATE; DISPERSION; SHEETS AB Texture, developed during the processing of zirconium and zirconium alloys, e.g,, ZIRCALOY, plays an important role in determining the properties and performance of the resultant structural components. Extending the work done on cubic metals, ultrasonic velocity measurements were used to nondestructively characterize the texture in hexagonal sheet metals. A theory is developed relating the texture coefficients W-LMN (L less than or equal to 4, found in an expansion of the crystallite orientation distribution function (ODF) in terms of generalized spherical harmonics) to industrially measured Kearns factors, which predict the fraction of basal poles aligned in a particular sample reference direction. Ultrasonic characterization of texture has been performed on three sheets of zirconium (one pure, two ZIRCALOY) and on one sheet of titanium. These results are compared to the Kearns factors, measured by X-ray diffraction (for the two ZIRCALOY sheets) and to the WLMN value measured by neutron diffraction (for the pure zirconium and the titanium). Results show that ultrasonics predict both the orientation distribution coefficients (ODCs) and the Kearns factors very well. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Ctr Nondestruct Evaluat, Ames, IA 50011 USA. Westinghouse Sci & Technol Ctr, Pittsburgh, PA 15235 USA. RP Anderson, AJ (reprint author), Sicon X, Keystone, SD 57752 USA. NR 33 TC 13 Z9 13 U1 0 U2 6 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD AUG PY 1999 VL 30 IS 8 BP 1981 EP 1988 DI 10.1007/s11661-999-0008-x PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 228WL UT WOS:000082159600008 ER PT J AU Barton, DL Osinski, M Perlin, P Eliseev, PG Lee, J AF Barton, DL Osinski, M Perlin, P Eliseev, PG Lee, J TI Single-quantum well InGaN green light emitting diode degradation under high electrical stress SO MICROELECTRONICS RELIABILITY LA English DT Article AB We performed a degradation study of high-brightness Nichia single-quantum well AlGaN/InGaN/GaN green light-emitting diodes (LEDs). The devices were subjected to high current electrical stress with current pulse amplitudes between 1 and 7 A and voltages between 10 and 70 V with a pulse length of 100 ns and a 1 kHz repetition rate. The study showed that when the current amplitude was increased above 6 A, a fast (about 1 s) degradation occurred, with a visible discharge between the p- and n-type electrodes. Subsequent failure analysis revealed severe damage to the metal contacts, which lead to the formation of shorts in the surface plane of the diode. For currents smaller than 6 A, a slow degradation was observed as a decrease in optical power and an increase in the reverse current leakage. However, a rapid degradation occurred between 24 and 100 h which was similar to the rapid degradation observed at higher currents. The failure analysis results indicate that the degradation process begins with carbonization of the plastic encapsulation material on the diode surface, which leads to the formation of a conductive path across the LED and subsequently to the destruction of the diode itself. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Elect Qual Reliabil Ctr, Albuquerque, NM 87185 USA. Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87131 USA. RP Sandia Natl Labs, Elect Qual Reliabil Ctr, MS1081, Albuquerque, NM 87185 USA. EM bartondl@sandia.gov NR 7 TC 40 Z9 45 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD AUG PY 1999 VL 39 IS 8 BP 1219 EP 1227 DI 10.1016/S0026-2714(99)00010-4 PG 9 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 251XT UT WOS:000083472200004 ER PT J AU Miller, SL Rodgers, MS La Vigne, G Sniegowski, JJ Clews, P Tanner, DM Peterson, KA AF Miller, SL Rodgers, MS La Vigne, G Sniegowski, JJ Clews, P Tanner, DM Peterson, KA TI Failure modes in surface micromachined microelectromechanical actuation systems SO MICROELECTRONICS RELIABILITY LA English DT Article ID FRICTION; DEVICES AB In order for the rapidly emerging field of MicroElectroMechanical Systems (MEMS) to meet its extraordinary expectations regarding commercial impact, issues pertaining to how they fail must be understood. We identify and address failure modes common to a broad range of MEMS actuation systems, including adhesion (stiction) and friction-induced failures caused by improper operational methods, mechanical instabilities, and electrical instabilities. Demonstrated methods to mitigate these failure modes include implementing optimized designs, model-based operational methods, and chemical surface treatments. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Miller, SL (reprint author), Sandia Natl Labs, POB 5800,MS 1080, Albuquerque, NM 87185 USA. NR 14 TC 19 Z9 22 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD AUG PY 1999 VL 39 IS 8 BP 1229 EP 1237 DI 10.1016/S0026-2714(99)00013-X PG 9 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 251XT UT WOS:000083472200005 ER PT J AU Weierstall, U Spence, JCH Stevens, M Downing, KH AF Weierstall, U Spence, JCH Stevens, M Downing, KH TI Point-projection electron imaging of tobacco mosaic virus at 40 eV electron energy SO MICRON LA English DT Review DE electron holography; tobacco mosaic virus; point-projection microscopy; radiation damage ID MICROSCOPY; HOLOGRAPHY AB In-line electron holograms of Tobacco mosaic virus (TMV) lying across holes in Quantifoil were recorded at 40 eV electron energy. The molecule is opaque at this energy and holographic reconstruction shows a projection image of the TMV. Radiation damage at this energy is expected to be confined to a thin surface layer of the molecule. Problems with the holographic reconstruction due to electric field inhomogeneity around the fiber are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Weierstall, U (reprint author), Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. RI Weierstall, Uwe/B-3568-2011 NR 13 TC 26 Z9 26 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0968-4328 J9 MICRON JI Micron PD AUG PY 1999 VL 30 IS 4 BP 335 EP 338 DI 10.1016/S0968-4328(99)00022-0 PG 4 WC Microscopy SC Microscopy GA 219AK UT WOS:000081584900006 ER PT J AU Wen, WW Killmeyer, RP Parekh, BK AF Wen, WW Killmeyer, RP Parekh, BK TI Centrifuge dewatering and reconstitution of fine coal: A pilot-plant application of the GranuFlow Process SO MINERALS & METALLURGICAL PROCESSING LA English DT Article DE dewatering; slurries; coal processing; screen-bowl centrifuge AB A continuous pilot-scale test of the GranuFlow Process was conducted using a screen-bowl centrifuge for the dewatering and reconstitution of column-flotation concentrate at a coal preparation plant in Virginia. In this test, a slipstream of the fine clean-coal slurry from the column flotation concentrate was treated with a bitumen emulsion before dewatering. The treated products from the screen-bowl centrifuge appeared to be dry and in a free-flowing granular form, while the untreated products were wet, sticky and difficult to handle. Test results indicated that the average moisture contents of the dewatered coal products were 35.7%, 35.5%, 32.6%, 29.9% and 26.5% (by weight) with Orimulsion additions of 0.0%, 0.7%, 3.2%, 4.8% and 6.4% (by weight), respectively. The handleability and dust reduction of the dewatered coal products were also vastly improved. C1 US Dept Energy, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. Univ Kentucky, Ctr Appl Energy Res, Lexington, KY 40511 USA. RP Wen, WW (reprint author), US Dept Energy, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SOC MINING METALLURGY EXPLORATION INC PI LITTLETON PA 8307 SHAFFER PARKWAY, LITTLETON, CO 80127 USA SN 0747-9182 J9 MINER METALL PROC JI Miner. Metall. Process. PD AUG PY 1999 VL 16 IS 3 BP 49 EP 52 PG 4 WC Metallurgy & Metallurgical Engineering; Mining & Mineral Processing SC Metallurgy & Metallurgical Engineering; Mining & Mineral Processing GA 258WD UT WOS:000083861800008 ER PT J AU Gary, R Park, MS Nolan, JP Cornelius, HL Kozyreva, OG Tran, HT Lobachev, KS Resnick, MA Gordenin, DA AF Gary, R Park, MS Nolan, JP Cornelius, HL Kozyreva, OG Tran, HT Lobachev, KS Resnick, MA Gordenin, DA TI A novel role in DNA metabolism for the binding of Fen1/Rad27 to PCNA and implications for genetic risk SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID CELL NUCLEAR ANTIGEN; NUCLEOTIDE EXCISION-REPAIR; SACCHAROMYCES-CEREVISIAE; ENDONUCLEASE ACTIVITY; FLAP ENDONUCLEASE-1; MUTATION AVOIDANCE; POLYMERASE-DELTA; REPLICATION FORK; MISMATCH REPAIR; STRANDED-DNA AB Fen1/Rad27 nuclease activity, which is important in DNA metabolism, is stimulated by proliferating cell nuclear antigen (PCNA) in vitro. The in vivo role of the PCNA interaction,vas investigated in the yeast Rad27. A nuclease-defective rad27 mutation had a dominant-negative effect that was suppressed by a mutation in the PCNA binding site, thereby demonstrating the importance of the Rad27-PCNA interaction. The PCNA-binding defect alone had little effect on mutation, recombination, and the methyl methanesulfonate (MMS) response in repair-competent cells, but it greatly amplified the MMS sensitivity of a rad51 mutant. Furthermore, the PCNA binding mutation resulted in lethality when combined with a homozygous or even a heterozygous pol3-01 mutation in the 3' --> 5' exonuclease domain of DNA polymerase delta. These results suggest that phenotypically mild polymorphisms in DNA metabolic proteins can have dramatic consequences when combined. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Gordenin, DA (reprint author), NIEHS, Mol Genet Lab, Mail Drop D3-01,101 TW Alexander Dr,POB 12233, Res Triangle Pk, NC 27709 USA. RI Gary, Ronald/A-8650-2008; OI Gary, Ronald/0000-0001-5079-1953; Gordenin, Dmitry/0000-0002-8399-1836 FU NCI NIH HHS [CA71630] NR 56 TC 80 Z9 81 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD AUG PY 1999 VL 19 IS 8 BP 5373 EP 5382 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 217RY UT WOS:000081513800014 PM 10409728 ER PT J AU Antokhin, E Buzykaev, A Chupyra, A Fedorov, D Ganzhur, S Kolachev, G Litvinov, A Medvedko, A Mikerov, V Mikhailov, S Onuchin, A Singatulin, S Aleksan, R Bourgeois, P Gosset, L Graffin, P London, G Mols, JP Toussaint, JC Berndt, M Coombes, R Ecklund, S Jensen, D Keller, L Krebs, J Lynch, H Wolf, Z AF Antokhin, E Buzykaev, A Chupyra, A Fedorov, D Ganzhur, S Kolachev, G Litvinov, A Medvedko, A Mikerov, V Mikhailov, S Onuchin, A Singatulin, S Aleksan, R Bourgeois, P Gosset, L Graffin, P London, G Mols, JP Toussaint, JC Berndt, M Coombes, R Ecklund, S Jensen, D Keller, L Krebs, J Lynch, H Wolf, Z TI Simulation and measurement of the fringe field of the 1.5 T BABAR solenoid SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE magnetic shielding; measurements of magnetic fields; finite element analysis; B-factory experiment; CP-violation AB In the context of the SLAG PEP-II asymmetric e(+)e(-) collider and the BABAR detector with its 1.5 T solenoid, we have calculated and measured the fringe field at the nearby beam elements and at the position of the photomultipliers external to the return iron but within a specially designed iron shield. The comparisons of these measurements with the simulations based on finite element analysis are remarkably good, within about 5 G at the most critical beam element. The field at the photomultipliers is less than 1 G, in agreement with the simulation. With a simple method of demagnetization of the shield, a maximum held of 0.6 G is obtained. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ctr Etud Saclay, CEA, DAPNIA, F-91191 Gif Sur Yvette, France. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP London, G (reprint author), Ctr Etud Saclay, CEA, DAPNIA, F-91191 Gif Sur Yvette, France. NR 9 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 1 PY 1999 VL 432 IS 1 BP 24 EP 47 DI 10.1016/S0168-9002(99)00278-8 PG 24 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 224XW UT WOS:000081926100003 ER PT J AU Orlando, TM Kimmel, GA Simpson, WC AF Orlando, TM Kimmel, GA Simpson, WC TI Quantum-resolved electron stimulated interface reactions: D-2 formation from D2O films SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 12th International Workshop on Inelastic Ion-Surface Collisions CY JAN 24-29, 1999 CL S PADRE ISL, TEXAS DE ion-surface interactions; electron stimulated desorption (ESD); water; desorption induced by electronic transitions (DIET) ID AMORPHOUS WATER ICE; MOLECULAR-HYDROGEN; ATTACHMENT; DESORPTION; H2O; SURFACE; ENERGY; EMISSION; RESONANCES; KINETICS AB The low-energy (5-15 eV) electron stimulated desorption of D- and D-2 ((1)Sigma(g)(+), upsilon = 0, J = 0 and upsilon = 1, J = 2) from condensed D2O films is investigated as a function of substrate temperature. The D- ions are produced primarily via the B-2(1) dissociative electron attachment resonance. Both the D- and D-2 yields are enhanced when the substrate temperature increases from 90 to 140 K. The changes in the D- and D-2 yields with substrate temperature are qualitatively similar. We attribute the increase in yields to thermally induced rotations or breaks in the near-surface hydrogen bonding network. This reduction in co-ordination and coupling reduces the nearest neighbor perturbations and enhances the surface or near surface excited state lifetimes. Production of vibrationally excited D-2 molecules correlates with reactive scattering of D- at the surface, whereas production of D-2 in the upsilon = 0 level also includes molecular elimination from an excited state which is produced by autodetachment. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Pacific NW Nat Lab, Environm Mol Sci Lab, WR Wiley, Richland, WA 99352 USA. RP Orlando, TM (reprint author), Pacific NW Nat Lab, Environm Mol Sci Lab, WR Wiley, Richland, WA 99352 USA. NR 34 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD AUG PY 1999 VL 157 IS 1-4 BP 183 EP 190 DI 10.1016/S0168-583X(99)00436-X PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 235JM UT WOS:000082538600028 ER PT J AU Wu, K Iedema, MJ Tsekouras, AA Cowin, JP AF Wu, K Iedema, MJ Tsekouras, AA Cowin, JP TI Probing aqueous-organic interfaces with soft-landed ions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 12th International Workshop on Inelastic Ion-Surface Collisions CY JAN 24-29, 1999 CL S PADRE ISL, TEXAS DE ions; hydronium; mobility; solvation; phase transfer AB A very low energy ion source (1 eV) is used to dose hydronium ions on or into epitaxially grown amorphous thin films of water and organic solvent, from tens to thousands of monolayers thick. This is done to probe the structure of the organic film, ion diffusion and solvation, and the kinetics of transfer of hydronium ions from an aqueous environment into a non-aqueous one. The organic solvent used is methyl cyclohexane. Water dosed from 0 to 0.5 monolayer on top of 60 monolayer films of methyl cyclohexane causes a solvation of ions co-adsorbed with the water, slowing the subsequent diffusion of ions through the solvent him. Water in excess of a monolayer causes extreme slowing of ion transfer into the organic phase. Structures in the film, clue to intentional doping or crystallization, are also probed via the ion motion. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Athens, Phys Chem Lab, GR-15771 Athens, Greece. RP Cowin, JP (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Battelle Blvd,POB 999,M-S K8-88, Richland, WA 99352 USA. RI Wu, Kai/A-4903-2011; OI Wu, Kai/0000-0002-5016-0251; Tsekouras, Athanassios/0000-0002-4757-324X NR 18 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD AUG PY 1999 VL 157 IS 1-4 BP 259 EP 269 DI 10.1016/S0168-583X(99)00459-0 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 235JM UT WOS:000082538600039 ER PT J AU Meyer, FW Morozov, VA AF Meyer, FW Morozov, VA TI Multicharged ion-surface measurements at ORNL MIRF using decelerated beams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 12th International Workshop on Inelastic Ion-Surface Collisions CY JAN 24-29, 1999 CL S PADRE ISL, TEXAS DE ion-surface scattering; energy loss; highly charged ions; neutralization; negative ion formation; charge exchange ID CHARGE EQUILIBRATION AB Studies are reported of low energy multicharged ion-surface interactions carried out at the ORNL MIRF (Multicharged Ion Research Facility) utilitizing recently developed apparatus that implements a UHV floating scattering chamber. By means of a zoom lens at the entrance to the chamber, beams can be decelerated to interaction energies as low as a few eV per charge. After a description of the new apparatus and of some diagnostic measurements of the decelerated beams, we present initial measurements of backscattered projectile energy loss and charge state distributions of multicharged carbon, oxygen, and argon ions incident on Au(1 1 0), with energies down to a few 100 eV/q, and incident angles ranging from normal to 70 degrees from normal. These results were obtained utilizing a TOF system with a biasable drift tube for charge state analysis. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Morozov, VA (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 9 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD AUG PY 1999 VL 157 IS 1-4 BP 297 EP 303 DI 10.1016/S0168-583X(99)00447-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 235JM UT WOS:000082538600045 ER PT J AU Avvakumov, S Adams, T Alton, A de Barbaro, L de Barbaro, P Berlin, D Bernstein, RH Bodek, A Bolton, T Brau, J Buchholz, D Budd, H Bugel, L Conrad, J Drucker, RB Frey, R Formaggio, J Goldman, J Goncharov, M Harris, DA Johnson, RA Koutsoliotas, S Kim, JH Krishnaswami, GK Lamm, MJ Marsh, W Mason, D McNulty, C McFarland, KS Naples, D Nienaber, P Romosan, A Sakumoto, WK Schellman, H Shaevitz, MH Spentzouris, P Stern, EG Tamminga, B Vakili, M Vaitaitis, A Wu, V Yang, UK Yu, J Zeller, GP AF Avvakumov, S Adams, T Alton, A de Barbaro, L de Barbaro, P Berlin, D Bernstein, RH Bodek, A Bolton, T Brau, J Buchholz, D Budd, H Bugel, L Conrad, J Drucker, RB Frey, R Formaggio, J Goldman, J Goncharov, M Harris, DA Johnson, RA Koutsoliotas, S Kim, JH Krishnaswami, GK Lamm, MJ Marsh, W Mason, D McNulty, C McFarland, KS Naples, D Nienaber, P Romosan, A Sakumoto, WK Schellman, H Shaevitz, MH Spentzouris, P Stern, EG Tamminga, B Vakili, M Vaitaitis, A Wu, V Yang, UK Yu, J Zeller, GP TI Performance of the NuTeV Fe-scintillator sampling calorimeter and implications for thin calorimeters SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN ID ENERGY AB NuTeV is a neutrino-nucleon deep inelastic scattering experiment at Fermilab. The NuTeV detector is a traditional heavy target neutrino detector which consists of an iron/liquid scintillator sampling calorimeter followed by a muon spectrometer. The calorimeter response to hadrons, muons and electrons has been measured in an in situ calibration beam over the energy range from 4.5 to 190 GeV. The small non-linearity of the response to hadrons is compared to the expectation from the measured ratio of responses between electrons and hadrons combined with the energy dependence of the fractional electromagnetic energy deposition in the form of neutral pions in hadronic showers f(pi)circle(E-pi). The predictions use f(pi)circle(E-pi) from the Monte Carlo simulations by GHEISHA, GFLUKA and GCALOR and also from the parameterizations of Wigmans and Groom. In addition, a study based on the NuTeV hadron calibration data of the effectiveness of a thin calorimeter is presented. The results of this study have important consequences for the energy resolution of calorimeters used in other applications; for example, measuring the cosmic ray flux in space or with balloon-based experiments. C1 Univ Cincinnati, Cincinnati, OH 45221 USA. Columbia Univ, New York, NY 10027 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Kansas State Univ, Manhattan, KS 66506 USA. Northwestern Univ, Evanston, IL 60208 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. RP Avvakumov, S (reprint author), Univ Cincinnati, Cincinnati, OH 45221 USA. RI Frey, Raymond/E-2830-2016; OI Frey, Raymond/0000-0003-0341-2636; Bodek, Arie/0000-0003-0409-0341; Krishnaswami, Govind/0000-0001-7988-4926; Bernstein, Robert/0000-0002-7610-950X NR 12 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 232 EP 237 DI 10.1016/S0920-5632(99)00550-2 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400037 ER PT J AU Back, B Betts, R Ganz, R Gulbrandsen, KH Holzman, B Kucewicz, W Lin, WT Mulmenstadt, J van Nieuwenhuizen, GJ Nouicer, R Pernegger, H Reuter, M Sarin, P Tsay, V Vale, CM Wadsworth, B Wuosmaa, A Wyslouch, B AF Back, B Betts, R Ganz, R Gulbrandsen, KH Holzman, B Kucewicz, W Lin, WT Mulmenstadt, J van Nieuwenhuizen, GJ Nouicer, R Pernegger, H Reuter, M Sarin, P Tsay, V Vale, CM Wadsworth, B Wuosmaa, A Wyslouch, B TI The PHOBOS silicon sensors SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB PHOBOS is one of the four experiments at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. PHOBOS almost exclusively utilizes silicon sensors to measure charged particle multiplicity distributions and to track particles in a 2-arm spectrometer. The detector consists of about 450 silicon pad sensors. Nine different pad geometries are used to match the different physics needs of the experiment. A relatively high granularity, of up to 1536 channels per sensor, is used in the spectrometer. The multiplicity detector uses 128 and 64 channel sensors and the charge deposition per pad is measured to determine the multiplicity of single events. All sensors are of the double-metal silicon pad type with pad sizes from 1 cm(2) up to 4 cm(2). They are produced in Taiwan by the ERSO foundry under supervision of Miracle Co. and National Central University. An extensive testing procedure makes it possible to select sensors suited for use in PHOBOS. Detector modules consisting of up to five sensors are read out with integrated chips of either 64 or 128 channels. The testing of the sensors and the performance of assembled detector modules is discussed. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Natl Cent Univ, High Energy Phys Grp, Dept Phys, Chungli 32054, Taiwan. Miracle Technol Co Ltd, Hsinchu, Taiwan. MIT, Cambridge, MA 02139 USA. RP Back, B (reprint author), Argonne Natl Lab, Div Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Muelmenstaedt, Johannes/K-2432-2015; OI Muelmenstaedt, Johannes/0000-0003-1105-6678; Reuter, Michael/0000-0003-3881-8310 NR 2 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 245 EP 251 DI 10.1016/S0920-5632(99)00552-6 PG 7 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400039 ER PT J AU Moromisato, J vonGoeler, E Reucroft, S Eartly, DP Hansen, S Droege, TF Cowden, E Lisafeld, J Prokofiev, DO AF Moromisato, J vonGoeler, E Reucroft, S Eartly, DP Hansen, S Droege, TF Cowden, E Lisafeld, J Prokofiev, DO TI A totally transparent alignment sensor SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB We describe the development of a totally transparent CCD based optical beam position sensing device that can measure transverse displacements with an accuracy of a few microns at a distance of many meters. The device includes on sensor DSP processing of the signal spectra with background subtraction and calibration to produce a compressed beam position, sensor address/status readout in token serial strings of sensors. The position monitoring system for the CMS Endcap Muon detector is presented as an intended application. C1 Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. RP Moromisato, J (reprint author), Northeastern Univ, Dept Phys, 110 Forsyth St, Boston, MA 02115 USA. 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 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 259 EP 262 DI 10.1016/S0920-5632(99)00554-X PG 4 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400041 ER PT J AU Roco, M AF Roco, M CA DO Collaboration TI The silicon microstrip tracker for the DO upgrade SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN ID DETECTORS AB The silicon microstrip tracker is a major element of the Dempty set detector upgrade at Fermilab. After a general overview of the silicon tracker design, results are presented for a series of detector and electronics performance studies which include beam tests and proton irradiation. Charge sharing and strip-to-strip uniformity studies using an infrared laser are also presented. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Roco, M (reprint author), Fermi Natl Accelerator Lab, MS 357,POB 500, Batavia, IL 60510 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 275 EP 280 DI 10.1016/S0920-5632(99)00557-5 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400044 ER PT J AU Lincoln, D AF Lincoln, D CA DO Collaboration Scintillating Fiber Detector G TI A large statistics study of the performance and yields of generation-6 VLPCs (HISTE-VI) SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB In this paper, the Dempty set collaboration reports on the test results of over 60 000 VLPC pixels. We have explored the space of operating conditions and find good performance at a temperature of 9 K and a bias voltage of 7 V. Preliminary tests have shown an average quantum efficiency of 80% and a gain of 25,000 - 50,000. Tests have shown that the devices can be made to work at very high rates. The pixel-to-pixel variation within a chip is manageable, allowing one to assemble like-performing VLPC chips into cassettes containing 1024 pixels each. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Lincoln, D (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 281 EP 286 DI 10.1016/S0920-5632(99)00558-7 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400045 ER PT J AU Azzi-Bacchetta, P Bacchetta, N Basti, A Bedeschi, F Bisello, D Blusk, S Chertok, M Chiarelli, G Demina, R Donati, S Field, R Galtieri, L Goldstein, J Grim, G Guerzoni, M Haber, C Hara, K Hartmann, F Heiss, A Hill, C Hrycyk, M Incandela, J Kato, Y Kim, BJ Knoblauch, D Kruse, M Lei, CM Leone, S Martignon, G Mcyntire, P Miyazaky, Y Moggi, A Muller, T Munar-Ara, A Okusawa, T Palmonari, F Pellett, D Piacentino, G Raffaelli, F Saltzberg, D Sanders, E Schilling, M Shimojima, M Stuart, D Takano, T Takikawa, K Tipton, P Turini, N Wenzel, H Zetti, F Zucchelli, S AF Azzi-Bacchetta, P Bacchetta, N Basti, A Bedeschi, F Bisello, D Blusk, S Chertok, M Chiarelli, G Demina, R Donati, S Field, R Galtieri, L Goldstein, J Grim, G Guerzoni, M Haber, C Hara, K Hartmann, F Heiss, A Hill, C Hrycyk, M Incandela, J Kato, Y Kim, BJ Knoblauch, D Kruse, M Lei, CM Leone, S Martignon, G Mcyntire, P Miyazaky, Y Moggi, A Muller, T Munar-Ara, A Okusawa, T Palmonari, F Pellett, D Piacentino, G Raffaelli, F Saltzberg, D Sanders, E Schilling, M Shimojima, M Stuart, D Takano, T Takikawa, K Tipton, P Turini, N Wenzel, H Zetti, F Zucchelli, S TI The CDF Intermediate Silicon Layers detector SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB The Intermediate Silicon Layers (ISL) detector is presently being built as part of CDF upgrades. The ISL is a large radius (28 cm) silicon tracker with a total active area of about 3.5 m(2). The challenge is to build a device which provides precise 3D points introducing a minimal amount of material for the supporting structure. The design and the status of the project are described. C1 Univ Pisa, I-56010 Pisa, Italy. Ist Nazl Fis Nucl, Sezione Pisa, I-56010 Pisa, Italy. Univ Florida, Gainesville, FL 32611 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Bologna, Ist Nazl Fis Nucl, Sezione Bologna, I-40126 Bologna, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Univ Karlsruhe, Inst Expt Kernphys, D-76148 Karlsruhe, Germany. Osaka City Univ, Osaka 588, Japan. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Padua, Ist Nazl Fis Nucl, Sezione Padova, I-35131 Padua, Italy. Univ Rochester, Rochester, NY 14627 USA. Texas A&M Univ, College Stn, TX 77843 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Donati, S (reprint author), Univ Pisa, I-56010 Pisa, Italy. RI Azzi, Patrizia/H-5404-2012; Chiarelli, Giorgio/E-8953-2012; Hill, Christopher/B-5371-2012; OI Azzi, Patrizia/0000-0002-3129-828X; Chiarelli, Giorgio/0000-0001-9851-4816; Hill, Christopher/0000-0003-0059-0779; Turini, Nicola/0000-0002-9395-5230; Goldstein, Joel/0000-0003-1591-6014 NR 4 TC 1 Z9 1 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 307 EP 310 DI 10.1016/S0920-5632(99)00562-9 PG 4 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400049 ER PT J AU Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Walsh, AM Wedenig, R Weilhammer, P White, C Ziock, H Zoeller, M AF Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Walsh, AM Wedenig, R Weilhammer, P White, C Ziock, H Zoeller, M CA RD42 Collaboration TI Recent results with CVD diamond trackers SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN ID READOUT AB We present recent results on the use of Chemical Vapor Deposition (CVD) diamond microstrip detectors for charged particle tracking. A series of detectors was fabricated using 1 x 1 cm(2) diamonds. Good signal-to-noise ratios were observed using both slow and fast readout electronics. For slow readout electronics, a mu s shaping time, the most probable signal-to-noise ratio was 50 to 1. For fast readout electronics, 25 ns peaking time, the most probable signal-to-noise ratio was 7 to 1. Using the first 2 x 4 cm(2) diamond from a production CVD reactor with slow readout electronics, the most probable signal-to-noise ratio was 23 to 1. The spatial resolution achieved for the detectors was consistent with the digital resolution expected from the detector pitch. C1 Ohio State Univ, Columbus, OH 43210 USA. Austrian Acad Sci, Inst Hochenergiephys, A-1050 Vienna, Austria. MPI Kernphys, D-69029 Heidelberg, Germany. GSI Darmstadt, D-6100 Darmstadt, Germany. CEA Saclay, SPE, DEIN, CEA Technol Avancees,LETI, F-91131 Gif Sur Yvette, France. LENS, Florence, Italy. Univ Florence, Florence, Italy. ULP, CNRS, IN2P3, LEPSI, F-67037 Strasbourg, France. Rutgers State Univ, Piscataway, NJ 08855 USA. CERN, CH-1211 Geneva 23, Switzerland. CPPM, F-13288 Marseille, France. LEPES, Grenoble, France. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Univ Turin, Turin, Italy. Univ Bristol, Bristol BS8 1TL, Avon, England. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ Pavia, Dipartimento Elettron, I-27100 Pavia, Italy. FNAL, Batavia, IL USA. Lab Hochenergiephys, CH-3012 Bern, Switzerland. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Toronto, Toronto, ON M5S 1A7, Canada. IIT, Chicago, IL 60616 USA. LANL, Los Alamos, NM 87545 USA. RP Gan, KK (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Krammer, Manfred/A-6508-2010; Lujan Center, LANL/G-4896-2012; Lo Giudice, Alessandro/J-4567-2012; Russ, James/P-3092-2014; Bruzzi, Mara/K-1326-2015; Bergonzo, Philippe/A-6567-2015; Gheeraert, Etienne/E-8071-2015 OI Sciortino, Silvio/0000-0003-0570-7489; Krammer, Manfred/0000-0003-2257-7751; vittone, ettore/0000-0003-3133-3687; Re, Valerio/0000-0003-0697-3420; Lo Giudice, Alessandro/0000-0003-4753-3165; Russ, James/0000-0001-9856-9155; Bruzzi, Mara/0000-0001-7344-8365; Bergonzo, Philippe/0000-0002-0647-9134; Gheeraert, Etienne/0000-0002-9952-5805 NR 4 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 329 EP 334 DI 10.1016/S0920-5632(99)00566-6 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400053 ER PT J AU Miao, CC AF Miao, CC CA DO Collaboration TI The DO Run II Luminosity Monitor SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN ID TOTAL CROSS-SECTION; DUAL PARTON MODEL; ROOT-S=546 AB The DO Run II Luminosity Monitor consists of plastic scintillation detectors with fine-mesh photomultiplier readout that cover the range 2.7 < \eta\ < 4.4 in pseudorapidity. The detector is designed to provide a precise measurement of the rate for non-diffractive inelastic collisions that is used to calculate the Tevatron luminosity at DO. Excellent time-of-flight resolution allows a clean separation between beam-beam interactions and the principal background fi om beam halo. In addition, timing is used to measure the position of the primary interaction vertex and to detect multiple interactions, Accurate correction for multiple proton-antiproton interactions in a single beam crossing is essential for an accurate luminosity determination. Associated electronics provide a single-interaction trigger term for the DO Level 1 trigger, and readout of the photomultiplier timing and pulse-height measurements. C1 Brown Univ, Dept Phys, Providence, RI 02912 USA. Fermilab, Batavia, IL 60510 USA. RP Miao, CC (reprint author), Brown Univ, Dept Phys, Box 1843, Providence, RI 02912 USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 342 EP 347 DI 10.1016/S0920-5632(99)00568-X PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400055 ER PT J AU Manzin, G AF Manzin, G TI The BABAR CsI(Tl) calorimeter SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB The BABAR electromagnetic calorimeter is composed of 6600 CsI(TI) crystals organized in a cylindrical barrel and a conical forward endcap. During the past year, the assembly of the two parts has been completed. The mechanical and optical properties of the crystals ase described, together with the readout and calibration systems and the progress in the construction of the system. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Manzin, G (reprint author), Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 454 EP 458 DI 10.1016/S0920-5632(99)00586-1 PG 5 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400073 ER PT J AU Wedenig, R Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Wagner, A Walsh, AM Weilhammer, P White, C Zeuner, W Ziock, H Zoeller, M Blanquart, L Breugnion, P Charles, E Ciocio, A Clemens, JC Dao, K Einsweiler, K Fasching, D Fischer, P Joshi, A Keil, M Klasen, V Kleinfelder, S Laugier, D Meuser, S Milgrome, O Mouthuy, T Richardson, J Sinervo, P Treis, J Wermes, N AF Wedenig, R Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hartjes, F Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Wagner, A Walsh, AM Weilhammer, P White, C Zeuner, W Ziock, H Zoeller, M Blanquart, L Breugnion, P Charles, E Ciocio, A Clemens, JC Dao, K Einsweiler, K Fasching, D Fischer, P Joshi, A Keil, M Klasen, V Kleinfelder, S Laugier, D Meuser, S Milgrome, O Mouthuy, T Richardson, J Sinervo, P Treis, J Wermes, N CA RD42 Collaboration ATLAS Pixel Grp TI CVD diamond pixel detectors for LHC experiments SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described. C1 CERN, CH-1211 Geneva 23, Switzerland. Akad Wissensch, Inst Hochenergiephys, A-1050 Vienna, Austria. MPI Kernphys, D-69029 Heidelberg, Germany. GSI Darmstadt, D-6100 Darmstadt, Germany. CEA Saclay, SPE, DEIN, CEA Technol Avancees,LETI, F-91191 Gif Sur Yvette, France. Univ Florence, Florence, Italy. Univ Strasbourg 1, CNRS, IN2P3, LEPSI, F-67037 Strasbourg, France. Rutgers State Univ, Piscataway, NJ 08855 USA. CPPM, F-13288 Marseille, France. LEPES, Grenoble, France. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Univ Turin, Turin, Italy. Ohio State Univ, Columbus, OH 43210 USA. Univ Bristol, Bristol BS8 1TL, Avon, England. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ Pavia, Dipartimento Elettr, I-27100 Pavia, Italy. FNAL, Batavia, IL USA. Lab Hochenergiephys, CH-3012 Bern, Switzerland. Univ Toronto, Toronto, ON M5S 1A7, Canada. IIT, Chicago, IL 60616 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Lawrence Berkeley Lab, Berkeley, CA USA. Univ Wisconsin, Madison, WI 53706 USA. Inst Phys, D-53115 Bonn, Germany. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. RP Wedenig, R (reprint author), CERN, CH-1211 Geneva 23, Switzerland. RI Krammer, Manfred/A-6508-2010; Lujan Center, LANL/G-4896-2012; Lo Giudice, Alessandro/J-4567-2012; Russ, James/P-3092-2014; Bruzzi, Mara/K-1326-2015; Bergonzo, Philippe/A-6567-2015; Gheeraert, Etienne/E-8071-2015; OI vittone, ettore/0000-0003-3133-3687; Re, Valerio/0000-0003-0697-3420; Krammer, Manfred/0000-0003-2257-7751; Lo Giudice, Alessandro/0000-0003-4753-3165; Russ, James/0000-0001-9856-9155; Bruzzi, Mara/0000-0001-7344-8365; Bergonzo, Philippe/0000-0002-0647-9134; Gheeraert, Etienne/0000-0002-9952-5805; Sciortino, Silvio/0000-0003-0570-7489 NR 6 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 497 EP 504 DI 10.1016/S0920-5632(99)00593-9 PG 8 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400080 ER PT J AU Bell, RA Berndt, M Burgess, W Craddock, W Dormicchi, O Fabbricatore, P Farinon, S Keller, L Moreschi, P Musenich, R O'Connor, TG Penco, R Priano, C Shen, S Valente, P AF Bell, RA Berndt, M Burgess, W Craddock, W Dormicchi, O Fabbricatore, P Farinon, S Keller, L Moreschi, P Musenich, R O'Connor, TG Penco, R Priano, C Shen, S Valente, P TI The BaBar superconducting coil: design, construction and test SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB The BABAR Detector, located in the PEP-II B-Factory at the Stanford Linear Accelerator Center, includes a large 1.5 Tesla superconducting solenoid, 2.8 m bore and length 3.7 m. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a +/- 3% field uniformity in the tracking region. This paper summarizes the 3 year design, fabrication and testing program of the superconducting solenoid. The work was carried out by an international collaboration between INFN, LLNL and SLAC. The coil was constructed by Ansaldo Energia. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Ansaldo Energia, Genoa, Italy. Ist Nazl Fis Nucl, I-16146 Genoa, Italy. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Bell, RA (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 559 EP 564 DI 10.1016/S0920-5632(99)00603-9 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400090 ER PT J AU Hartjes, F Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Wagner, A Walsh, AM Wedenig, R Weilhammer, P White, C Zeuner, W Ziock, H Zoeller, M AF Hartjes, F Adam, W Bauer, C Berdermann, E Bergonzo, P Bogani, F Borchi, E Brambilla, A Bruzzi, M Colledani, C Conway, J Dabrowski, W Delpierre, P Deneuville, A Dulinski, W van Eijk, B Fallou, A Fizzotti, F Foulon, F Friedl, M Gan, KK Gheeraert, E Grigoriev, E Hallewell, G Hall-Wilton, R Han, S Hrubec, J Husson, D Kagan, H Kania, D Kaplon, J Karl, C Kass, R Knopfle, KT Krammer, M Logiudice, A Lu, R Manfredi, PF Manfredotti, C Marshall, RD Meier, D Mishina, M Oh, A Pan, LS Palmieri, VG Pernicka, M Peitz, A Pirollo, S Polesello, P Pretzl, K Procario, M Re, V Riester, JL Roe, S Roff, D Rudge, A Runolfsson, O Russ, J Schnetzer, S Sciortino, S Speziali, V Stelzer, H Stone, R Suter, B Tapper, RJ Tesarek, R Trawick, M Trischuk, W Vittone, E Wagner, A Walsh, AM Wedenig, R Weilhammer, P White, C Zeuner, W Ziock, H Zoeller, M CA RD42 Collaboration TI Parameterisation of radiation effects on CVD diamond for proton irradiation SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB The paper reviews measurements of the radiation hardness of CVD diamond for 24 GeV/c proton irradiation at fluences up to 5*10(15) protons/cm(2). The results not only show radiation damage but also an annealing effect that is dominant at levels around 10(15) protons/cm(2). A model describing both effects is introduced, enabling a prediction of the distribution curve of the charge signal for other levels. C1 NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Austrian Acad Sci, Inst Hochenergiephys, A-1050 Vienna, Austria. MPI Kernphys, D-69029 Heidelberg, Germany. GSI Darmstadt, D-6100 Darmstadt, Germany. CEA Saclay, SPE, DEIN, LETI, F-91191 Gif Sur Yvette, France. LENS, Florence, Italy. Univ Florence, Florence, Italy. ULP, CNRS, IN2P3, LEPSI, F-67037 Strasbourg, France. Rutgers State Univ, Piscataway, NJ 08855 USA. CERN, CH-1211 Geneva 23, Switzerland. CPPM, F-13288 Marseille, France. LEPES, Grenoble, France. Univ Turin, Turin, Italy. Ohio State Univ, Columbus, OH 43210 USA. Univ Bristol, Bristol BS8 1TL, Avon, England. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ Pavia, Dipartimento Elettr, I-27100 Pavia, Italy. FNAL, Batavia, IL USA. Lab Hochenergiephys, CH-3012 Bern, Switzerland. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Toronto, Toronto, ON M5S 1A7, Canada. IIT, Chicago, IL 60616 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hartjes, F (reprint author), NIKHEF H, NL-1009 DB Amsterdam, Netherlands. RI Krammer, Manfred/A-6508-2010; Lujan Center, LANL/G-4896-2012; Lo Giudice, Alessandro/J-4567-2012; Russ, James/P-3092-2014; Bruzzi, Mara/K-1326-2015; Bergonzo, Philippe/A-6567-2015; Gheeraert, Etienne/E-8071-2015; OI Sciortino, Silvio/0000-0003-0570-7489; Krammer, Manfred/0000-0003-2257-7751; Lo Giudice, Alessandro/0000-0003-4753-3165; Russ, James/0000-0001-9856-9155; Bruzzi, Mara/0000-0001-7344-8365; Bergonzo, Philippe/0000-0002-0647-9134; Gheeraert, Etienne/0000-0002-9952-5805; vittone, ettore/0000-0003-3133-3687; Re, Valerio/0000-0003-0697-3420 NR 3 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 675 EP 682 DI 10.1016/S0920-5632(99)00623-4 PG 8 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400110 ER PT J AU Cosmo, G AF Cosmo, G TI The BABAR software architecture and infrastructure SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Advanced Technology and Particle Physics CY OCT 05-09, 1998 CL VILLA OLMO, ITALY SP European Phys Soc, Inst Nazionale Fis Nucleare, Univ Florence, INFN AB The BABAR experiment has in place since 1995 a software release system (SRT Software Release Tools) based on CVS (Concurrent Version System) which is in common for all the software developed far the experiment, online or offline, simulation or reconstruction. A software release is a snapshot of all BABAR code (online, offline, utilities; scripts, makefiles, etc.). This set of code is tested to work together, and is indexed by a release number (e.g., 6.8.2) so a user can refer to a particular release and get reproducible results. A release will involve particular versions of packages. A package generally consists of a set of code for a particular task, together with a GNUmakefile, scripts and documentation. All BABAR software is maintained in AFS (Andrew File System) directories, so the code is accessible worldwide within the Collaboration. The combination SRT, CVS, AFS, has demonstrated to be a valid, powerful and efficient way of organizing the software infrastructure of a modern HEP experiment with collaborating Institutes distributed worldwide, both in a development and production phase. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Cosmo, G (reprint author), Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD AUG PY 1999 VL 78 BP 732 EP 737 DI 10.1016/S0920-5632(99)00632-5 PG 6 WC Physics, Particles & Fields SC Physics GA 249AJ UT WOS:000083309400119 ER PT J AU Ryabtsev, AN Churilov, SS Nilsen, J Li, Y Dunn, J Osterheld, AL AF Ryabtsev, AN Churilov, SS Nilsen, J Li, Y Dunn, J Osterheld, AL TI Additional analysis of the spectra of Ni-like ions SO OPTICS AND SPECTROSCOPY LA English DT Article ID X-RAY LASER; NICKEL-LIKE IONS; ISOELECTRONIC SEQUENCE; TRANSITIONS; NM AB The theoretical and experimental analysis of the spectra of Ni-like ions was made, which made it possible to determined more correctly wavelengths of the 4p(1)P(1)-4d(1)S(0) laser transitions in the YXII-MoXV ions and identify for the first time these transitions in the AsVI, BrVIII, and RbX ions. For the MoXV ion, the lines of the 3d(9)4p-3d(9)4d transitions were identified, and from a list of 18 levels of the 3d(9)4d configuration, the energies of 14 levels were measured. Moreover, the strongest lines of the 3d(9)4d-3d(9)4f transitions in the RbX-MoXV ions were identified and energies for a number of levels of the 3d(9)4f configuration for these ions were determined. C1 Russian Acad Sci, Inst Spect, Troitsk 142092, Moscow Oblast, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Ryabtsev, AN (reprint author), Russian Acad Sci, Inst Spect, Troitsk 142092, Moscow Oblast, Russia. NR 15 TC 3 Z9 3 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0030-400X J9 OPT SPECTROSC+ JI Opt. Spectrosc. PD AUG PY 1999 VL 87 IS 2 BP 181 EP 186 PG 6 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 235RG UT WOS:000082555900004 ER PT J AU Gosnell, TR AF Gosnell, TR TI Laser cooling of a solid by 65 K starting from room temperature SO OPTICS LETTERS LA English DT Article ID GLASSES AB In vacuo laser cooling of a solid from 301 to 236 R has been demonstrated. The sample consists of a cladded, multimode optical fiber fabricated from the fluorozirconate glass ZBLANP; the fiber's waveguiding core is doped with 1 wt. % Yb3+ ions. Cooling of the host glass results hom anti-Stokes fluorescence of Yb3+ following optical pumping in the long-wavelength tail of the ion's absorption spectrum (lambda = 1015 nm). Measurement of the time constant for equilibration of the sample temperature is in excellent agreement with an analytic calculation of this quantity. (C) 1999 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Gosnell, TR (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Mail Stop E543, Los Alamos, NM 87545 USA. NR 10 TC 96 Z9 104 U1 1 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 1 PY 1999 VL 24 IS 15 BP 1041 EP 1043 DI 10.1364/OL.24.001041 PG 3 WC Optics SC Optics GA 220ZY UT WOS:000081700800013 PM 18073934 ER PT J AU Sankaran, V Everett, MJ Maitland, DJ Walsh, JT AF Sankaran, V Everett, MJ Maitland, DJ Walsh, JT TI Comparison of polarized-light propagation in biological tissue and phantoms SO OPTICS LETTERS LA English DT Article ID SCATTERING; MEDIA AB We demonstrate significant differences in the propagation of polarized light through biological tissue compared with two common tissue phantoms. Depolarization of linearly and circularly polarized light was measured versus propagation distance by use of two independent measurement techniques. The measurements were performed on adipose and myocardial tissues and on tissue phantoms that consisted of polystyrene microsphere suspensions and Intralipid. The results indicate that, in contrast with results obtained in tissue phantoms, linearly polarized light survives through longer propagation distances than circularly polarized light in biological tissue. (C) 1999 Optical Society of America. C1 Univ Calif Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94551 USA. Northwestern Univ, Dept Biomed Engn, Evanston, IL 60208 USA. RP Sankaran, V (reprint author), Univ Calif Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94551 USA. RI Walsh, Joseph/B-7636-2009 NR 15 TC 101 Z9 105 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 1 PY 1999 VL 24 IS 15 BP 1044 EP 1046 DI 10.1364/OL.24.001044 PG 3 WC Optics SC Optics GA 220ZY UT WOS:000081700800014 PM 18073935 ER PT J AU Haynes, JA Ferber, MK Porter, WD Rigney, ED AF Haynes, JA Ferber, MK Porter, WD Rigney, ED TI Characterization of alumina scales formed during isothermal and cyclic oxidation of plasma-sprayed TBC systems at 1150 degrees C SO OXIDATION OF METALS LA English DT Article DE TBC; scale fracture; oxide scales; voids; alumina ID THERMAL BARRIER COATINGS; OXIDE-SCALE; REACTIVE-ELEMENT; FAILURE MECHANISMS; BEHAVIOR; GROWTH; SUPERALLOYS; ADHERENCE; ADHESION; YTTRIUM AB The isothermal- and cyclic-oxidation behavior of thermal barrier coating (TBC) systems consisting of vacuum plasma-sprayed (VPS) Ni-22Cr-10Al-1Y (wt.%) bond coatings and air plasma-sprayed (APS) Y2O3-stabilized ZrO2 (YSZ) top coatings (on single-crystal superalloys) was investigated. The microstructures, flaw contents, and fracture behavior of the Al2O3 scales formed during oxidation testing at 1150 degrees C were characterized (by analysis of coating and scale fracture surfaces and metallographic cross sections). Significant localized fracture and buckling of the Al2O3 scales that formed along the bond-coat-top-coat interfaces were observed after cyclic oxidation of TBCs. However, substantial amounts of localized scale damage did not induce rapid TBC failure. Decohesion of the columnar alumina scales on the rough bond-coat surfaces occurred by both internal Al2O3 fracture (parallel to the metal surface) and oxide-metal delamination. There were microstructural indications of Al2O3 scale crack healing by sintering into planar arrays of voids. Alumina scales that formed on convex NiCrAlY surfaces (with radii of 50 mu m or less) often contained significant amounts of internal voids (along grain boundaries) after cyclic oxidation, whereas scales formed by isothermal oxidation contained few visible voids. Accelerated void growth in Al2O3 scales on the irregular NiCrAlY surfaces appeared to be creep-related and was attributed to the synergistic effects of geometric and thermal stresses. C1 Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. Univ Alabama, Dept Mech & Mat Engn, Birmingham, AL 35923 USA. RP Haynes, JA (reprint author), Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. NR 56 TC 67 Z9 69 U1 1 U2 24 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0030-770X J9 OXID MET JI Oxid. Met. PD AUG PY 1999 VL 52 IS 1-2 BP 31 EP 76 DI 10.1023/A:1018870923397 PG 46 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 206PJ UT WOS:000080888000002 ER PT J AU Guilderson, TP Schrag, DP AF Guilderson, TP Schrag, DP TI Reliability of coral isotope records from the western Pacific warm pool: A comparison using age-optimized records SO PALEOCEANOGRAPHY LA English DT Article ID SEA-SURFACE TEMPERATURE; AIR-TEMPERATURE; FRACTIONATION; PATTERNS; CARBON; C-13 AB Stable isotope analysis of two separate corals from Nauru Island in the warm pool of the western tropical Pacific confirm that coral oxygen isotopes are a robust recorder of environmental variables. Coral delta(18)O faithfully records interannual variability even when strongly influenced by kinetic effects. Interannual to decadal variability of coral delta(13)C remains enigmatic; only one of the two corals exhibits the expected light-delta(13)C response in the interannual band. Coral delta(18)O from this region has a great similarity to global instrumental temperature records reflecting the impact of the Pacific warm pool and variations of the Indonesian Low in concert with El Nino-Southern Oscillation on global climate. Since 1896, coral delta(18)O has exhibited a cumulative decrease of 0.7 parts per thousand, which reflects a combination of warming and more frequent El Nino events (precipitation) affecting the surface waters of this region. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Guilderson, TP (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 20 Oxford St, Cambridge, MA 02138 USA. NR 33 TC 58 Z9 60 U1 3 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD AUG PY 1999 VL 14 IS 4 BP 457 EP 464 DI 10.1029/1999PA900024 PG 8 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA 218QZ UT WOS:000081564300004 ER PT J AU Gomez-Garcia, D Martinez-Fernandez, J Dominguez-Rodriguez, A Westmacott, KH AF Gomez-Garcia, D Martinez-Fernandez, J Dominguez-Rodriguez, A Westmacott, KH TI On the influence of heat treatments in a reducing atmosphere on the mechanical behaviour of yttria fully stabilized zirconia single crystals SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID HIGH-TEMPERATURE CREEP; Y2O3-STABILIZED ZRO2; PLASTIC-DEFORMATION; ORIGIN AB The influence of heat treatments in a reducing atmosphere prior to deformation on the high-temperature mechanical behaviour of yttria fully stabilized zirconia single crystals has been analysed. According to the present results, the yield stress decreases significantly for reduced samples. The phenomenon correlates quite well with the dynamics of defects and gives a clue about their influence on mechanical properties. C1 Univ Sevilla, CSIC, Dept Fis Mat Condensada, Inst Ciencia Mat, E-41080 Seville, Spain. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RP Gomez-Garcia, D (reprint author), Univ Sevilla, CSIC, Dept Fis Mat Condensada, Inst Ciencia Mat, Apartado Correos 1065, E-41080 Seville, Spain. RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; Gomez Garcia, Diego/H-3993-2015; OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; Gomez Garcia, Diego/0000-0002-5639-4796; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 19 TC 3 Z9 3 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1999 VL 79 IS 8 BP 1839 EP 1852 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 223GD UT WOS:000081831800006 ER PT J AU Shah, V Yang, LQ AF Shah, V Yang, LQ TI Nanometre fcc clusters versus bulk bcc alloy: the structure of Cu-Pd catalysts SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID PALLADIUM-COPPER ALLOYS; EMBEDDED-ATOM-METHOD; BIMETALLIC CLUSTERS; MOLECULAR-DYNAMICS; SURFACE SEGREGATION; BODY FORMULATION; METAL-CLUSTERS; NI; SIMULATIONS; ENERGETICS AB We present a simple method to improve the accuracy of the calculated heat of mixing for the Cu-Pd alloy within the formalism of the molecular dynamics/Monte Carlo-corrected effective medium (MD/MC-CEM) theory by adding a fitted Morse potential to the pair interaction between Cu and Pd atoms. This leads to a much better agreement between the theoretical and experimental Values of heats of mixing for five different compositions of the Cu-Pd alloy in the bulk phases. Using this newly fitted model, we have performed simulations on CuPd clusters consisting of 50-10 000 atoms with fee and bce structures. Our calculations show that in the range of cluster sizes of several thousand atoms, the fee structure is energetically favoured over the bcc structure. We estimate an approximate size for the fcc to bcc (CsCl, known bulk structure for CuPd) transition in these clusters to be around 10 000 atoms. Additionally, we have also performed calculations of the X-ray diffraction patterns of a variety of cluster geometries and sizes. The calculated X-ray diffraction pattern of a slightly distorted fee cluster exhibits the main features observed in the available experimental diffraction patterns of colloidal bimetallic catalysts of CuPd. The calculated diffraction patterns of bcc clusters are quite different from the experimental data. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Shah, V (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 38 TC 14 Z9 16 U1 3 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD AUG PY 1999 VL 79 IS 8 BP 2025 EP 2049 PG 25 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 223GD UT WOS:000081831800018 ER PT J AU Johnson, DD Asta, M Althoff, JD AF Johnson, DD Asta, M Althoff, JD TI Temperature-dependent chemical ordering in bcc-based ternary alloys: a theoretical study of Ti-Al-Nb SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID CLUSTER VARIATION METHOD; NI-ZN SYSTEM; METALLIC ALLOYS; SOLID-SOLUTIONS; PHASE; ORIGINS AB In contrast to binaries, chemical ordering in N-component alloys is described by N-2 concentration wave 'polarizations' in addition to the usual wave vector(s) which specify the direction and period of the compositional modulation. We demonstrate how these polarizations may be calculated as a function of composition and temperature using two different electronic-structure-based approaches. We use bcc-based Ti-Al-Nb alloys as specific examples. Calculated results are compared with recent transmission electron microscopy (TEM) and neutron-scattering (NS) data from partially-ordered alloys. While the agreement with TEM data is excellent, slight discrepancies are obtained with NS data which result, as we discuss, from assumptions made in the Rietveld analyses. We also demonstrate that the effect of temperature on the polarizations, often neglected in the experimental analysis, can be significant. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Sandia Natl Labs, Computat Mat Sci Dept, Livermore, CA 94551 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 95720 USA. RP Johnson, DD (reprint author), Univ Illinois, Dept Mat Sci & Engn, 1304 W Green St, Urbana, IL 61801 USA. OI Johnson, Duane/0000-0003-0794-7283 NR 26 TC 9 Z9 9 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD AUG PY 1999 VL 79 IS 8 BP 551 EP 559 DI 10.1080/095008399176922 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 223GB UT WOS:000081831600008 ER PT J AU Setlow, RB AF Setlow, RB TI Raymond Latarjet 1911-1998 SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Biographical-Item C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Setlow, RB (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD AUG PY 1999 VL 70 IS 2 BP V EP VII PG 3 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 226MG UT WOS:000082023300001 ER PT J AU Moan, J Dahlback, A Setlow, RB AF Moan, J Dahlback, A Setlow, RB TI Epidemiological support for an hypothesis for melanoma induction indicating a role for UVA radiation SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SKIN-CANCER; ULTRAVIOLET-RADIATION; MALIGNANT-MELANOMA; OZONE DEPLETION; SUNSCREENS; LATITUDES; ERYTHEMA; ALBINOS; DAMAGE AB An hypothesis for melanoma induction is presented: UV radiation absorbed by melanin in melanocytes generates products that may activate the carcinogenic process. Products formed by UV absorption in the upper layers of the epidermis cannot diffuse down as far as to the melanocytes. Thus, melanin in the upper layer of the skin may be protective, while that in melanocytes may be photocarcinogenic. Observations that support this hypothesis include: (I) Africans with dark skin have a reduced risk of getting all types of skin cancer as compared with Caucasians, but the ratio of their incidence rates of cutaneous malignant melanoma to that of squamous cell carcinoma is larger than the corresponding ratio for Caucasians, (2) Albino Africans, as compared with normally pigmented Africans, seem to have a relatively small risk of getting cutaneous malignant melanomas compared to nonmelanomas. This is probably also true for albino and normally pigmented Caucasians. (3) Among sun-sensitive, poorly tanning persons, frequent UV exposures are associated with increased risk of melanoma, wherease among sun-resistant, well-tanning persons, increased frequency of exposure is associated with decreased melanoma risk. (4) It is likely that WA, being absorbed by melanin, might have a melanoma-inducing effect. This is in agreement with some epidemiological investigations which indicate that sun-screen lotions may not protect sufficiently against melanoma induction. The relative latitude gradient for WA is much smaller than that for UVB. The same is true for the relative latitude gradient of cutaneous malignant melanoma as compared with squamous cell carcinoma and basal cell carcinoma. Under the assumption that the average slopes of the curves relating incidence rates with fluences of carcinogenic UV radiation are similar for melanomas and nonmelanomas, these facts are in agreement with the assumption that UVA plays a significant role in the induction of melanomas in humans. This is in agreement with the experimental results with Xiphophorus. C1 Inst Canc Res, Dept Biophys, N-0310 Oslo, Norway. Univ Oslo, Inst Phys, Oslo, Norway. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Moan, J (reprint author), Inst Canc Res, Dept Biophys, Ullernchausseen 70, N-0310 Oslo, Norway. NR 34 TC 149 Z9 149 U1 0 U2 7 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD AUG PY 1999 VL 70 IS 2 BP 243 EP 247 DI 10.1111/j.1751-1097.1999.tb07995.x PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 226MG UT WOS:000082023300018 PM 10461463 ER PT J AU Sun, EY Goyal, A Norton, DP Park, C Kroeger, DM Paranthaman, M Christen, DK AF Sun, EY Goyal, A Norton, DP Park, C Kroeger, DM Paranthaman, M Christen, DK TI High-resolution transmission electron microscopy/analytical electron microscopy characterization of epitaxial oxide multilayers fabricated by laser ablation on biaxially textured Ni SO PHYSICA C LA English DT Article DE TEM; AEM; laser ablation ID CRITICAL-CURRENT DENSITY; SUPERCONDUCTING TAPES; TRANSPORT-PROPERTIES; GRAIN-BOUNDARY; BUFFER LAYERS; THICK-FILMS; DEPOSITION; BICRYSTALS; YBA2CU3O7 AB Microstructural characterization of rolling-assisted biaxially textured substrates (RABiTS) was conducted using high-resolution transmission electron microscopy (TEM) and high-resolution analytical electron microscopy (AEM). RABiT substrates with a multilayer configuration YSZ (0.2 mu m)/CeO2 (0.9 mu m)/Ni (125 mu m) were studied. The substrates were fabricated by epitaxial deposition of oxide layers using laser ablation on biaxially textured Ni substrates. High critical current density YBa2Cu3Ox thick films have been fabricated on such RABiT substrates and typically yield J(c) values over 1 MA/cm(2). TEM examinations show that a reaction layer 10-40 nm thick is formed at the CeO2/Ni interface. Detailed microstructural and chemical analyses indicate that the layer is epitaxial {001} nickel oxide on {001} Ni. The CeO2 layer is found to consist of three distinct morphologies corresponding to the growth atmosphere during the deposition. The YSZ layer exhibited a columnar structure aligned along the [100] axis, with little or no orientation variation between the columns. The interface between the YSZ and CeO2 layers is atomically sharp and neither interdiffusion of elements nor an interfacial reaction layer is observed, Implications of these results on processing are discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. RP Goyal, A (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Yoon, Sejin/F-7637-2013; Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 19 TC 9 Z9 13 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 1 PY 1999 VL 321 IS 1-2 BP 29 EP 38 DI 10.1016/S0921-4534(99)00342-1 PG 10 WC Physics, Applied SC Physics GA 235HN UT WOS:000082536400003 ER PT J AU Garisto, R Hardy, L AF Garisto, R Hardy, L TI Entanglement of projection and a new class of quantum erasers SO PHYSICAL REVIEW A LA English DT Article ID INDUCED COHERENCE; STATE; COMPLEMENTARITY; INEQUALITIES; INTERFERENCE; MECHANICS AB We define a new measurement of entanglement, the entanglement of projection, and find that it is natural to write the entanglements of formation and assistance in terms of it. Our measure allows us to describe a new class of quantum erasers which restore entanglement rather than just interference. Such erasers can be implemented with simple quantum computer components. We propose realistic optical versions of these erasers. [S1050-2947(99)02508-1]. C1 Brookhaven Natl Lab, Theory Grp, Upton, NY 11973 USA. Clarendon Lab, Oxford OX1 3PU, England. RP Garisto, R (reprint author), Brookhaven Natl Lab, Theory Grp, Bldg 510A, Upton, NY 11973 USA. OI Garisto, Robert/0000-0002-1204-2035 NR 24 TC 21 Z9 21 U1 0 U2 1 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 1999 VL 60 IS 2 BP 827 EP 831 DI 10.1103/PhysRevA.60.827 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900019 ER PT J AU Mosse, C Calisti, A Stamm, R Talin, B Lee, R Klein, L AF Mosse, C Calisti, A Stamm, R Talin, B Lee, R Klein, L TI Redistribution of resonance radiation in hot and dense plasmas SO PHYSICAL REVIEW A LA English DT Article ID X-RAY LASERS; PROFILE CALCULATIONS; LINE-SHAPE; C-IV; N-V; FLUORESCENCE; SPECTROSCOPY; ABSORPTION; N=4 AB A method for calculating the redistribution of resonance radiation in hot, dense plasmas is developed by extending the frequency fluctuation model (FFM). This model was originally designed as a numerical procedure for the calculation of the spectral shape of Stark-broadened lines emitted by multielectron ions and has been particularly useful in computations accounting for the ion dynamics effect. The FFM is based on a numerical technique that replaces the primitive inhomogeneous Stark component contributions to the linear response line shape with the observable radiative channels. These channels can be viewed as equivalent to a system of microfield dressed two-level radiators, the Stark-dressed transitions (SDT), which emit a set of spectral lines that reproduce the main features of the first-order radiative properties of the emitter. The mixing of these transitions through a stochastic process is equivalent to random fluctuations of the local ion microfield. The SDT form the basis for the extension of the FFM to the computation of nonlinear response functions. The theory of the second-order radiative redistribution function is reviewed and examples are given. [S1050-2447(99)08008-7]. C1 Univ Aix Marseille 1, UMR 6633, Ctr St Jerome, F-13397 Marseille 20, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Howard Univ, Dept Phys, Washington, DC 20059 USA. RP Mosse, C (reprint author), Univ Aix Marseille 1, UMR 6633, Ctr St Jerome, Case 232, F-13397 Marseille 20, France. RI Mosse, Caroline/F-9192-2013; OI Calisti, Annette/0000-0001-6727-9286 NR 29 TC 21 Z9 20 U1 0 U2 1 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 1999 VL 60 IS 2 BP 1005 EP 1014 DI 10.1103/PhysRevA.60.1005 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900040 ER PT J AU Arbo, DG Reinhold, CO Kurpick, P Yoshida, S Burgdorfer, J AF Arbo, DG Reinhold, CO Kurpick, P Yoshida, S Burgdorfer, J TI Quantum transport theory for atomic states through solids SO PHYSICAL REVIEW A LA English DT Article ID RELATIVISTIC H IONS; HALF-CYCLE PULSES; MEAN FREE PATHS; THIN FOILS; ANGULAR-DISTRIBUTIONS; CROSS-SECTIONS; RYDBERG STATES; HYDROGEN-ATOM; COLLISIONS; IONIZATION AB We present a quantum description for the evolution of atomic states of fast projectiles traveling through matter. Our approach is based on the solution of a quantum Langevin equation, i.e., a stochastic time-dependent Schrodinger equation that describes electronic excitations of atoms during their transport through solids. The present description can be considered the quantized version of a previously developed classical transport theory. We analyze in detail the correspondence between classical and quantum transport simulations. Applications to the stripping of relativistic H- and H through thin carbon foils and a comparison with experimental data are presented. [S1050-2947(99)00308-X]. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Inst Astron & Fis Espacio, RA-1428 Buenos Aires, DF, Argentina. Vienna Tech Univ, Inst Theoret Phys, A-1040 Vienna, Austria. RP Arbo, DG (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. OI Reinhold, Carlos/0000-0003-0100-4962 NR 56 TC 13 Z9 13 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 1999 VL 60 IS 2 BP 1091 EP 1102 DI 10.1103/PhysRevA.60.1091 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900048 ER PT J AU Kimball, DF Clyde, D Budker, D DeMille, D Freedman, SJ Rochester, S Stalnaker, JE Zolotorev, M AF Kimball, DF Clyde, D Budker, D DeMille, D Freedman, SJ Rochester, S Stalnaker, JE Zolotorev, M TI Collisional perturbation of states in atomic ytterbium by helium and neon SO PHYSICAL REVIEW A LA English DT Article ID PARITY NONCONSERVATION; YB; TRANSITION; LIFETIMES; VIOLATION; SHIFTS AB Results of an investigation of collisional deexcitation of the metastable 6s6p P-3(0) state in atomic ytterbium by helium and neon buffer gases are reported. We find upper limits for the quenching cross sections to be sigma(He)<13X10(-22) cm(2) and sigma(Ne)<8x10(-22) cm(2). The small cross sections may allow an ytterbium parity nonconservation experiment to be performed in a vapor cell. We have also measured the pressure broadening and shift of the 6s6p P-3(0)-->6s7s S-3(1) and 6s(2) S-1(0)-->6s6p P-3(1) transitions by helium and neon. [S1050-2947(99)00408-4]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Budker, Dmitry/F-7580-2016 OI Budker, Dmitry/0000-0002-7356-4814 NR 32 TC 11 Z9 11 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1999 VL 60 IS 2 BP 1103 EP 1112 DI 10.1103/PhysRevA.60.1103 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900049 ER PT J AU Yoshida, S Watanabe, S Reinhold, CO Burgdorfer, J AF Yoshida, S Watanabe, S Reinhold, CO Burgdorfer, J TI Reflection-free propagation of wave packets SO PHYSICAL REVIEW A LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; HYDROGEN-ATOM; QUANTUM-THEORY; IONIZATION; FIELDS; STABILIZATION; RESONANCES; EVOLUTION; DYNAMICS; SYSTEMS AB We analyze the problem of suppression of reflections within the numerical propagation of wave packets using finite atomiclike pseudostate expansions. Artificial reflections at effective "walls" and reentering of probability flux into the interaction region represents a major limitation for the study of long-time evolution of atomic ionization processes. We propose two methods, the repetitive projection method (RPM) and Siegert pseudostate (SPS) propagation, and study their efficiency in Suppressing reflections. It is shown that the quantum Zeno effect sets a limit on the efficiency of the RPM as well as of masking functions. For the exactly solvable propagation of a radial-free wave packet, we show that both the SPS and the RPM provide almost complete suppression of reflections without appreciable distortion in the physically relevant region of coordinate space. [S1050-2947(99)03908-6]. C1 Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Electrocommun, Dept Appl Phys, Chofu, Tokyo 1828585, Japan. Vienna Tech Univ, Inst Theoret Phys, A-1040 Vienna, Austria. RP Yoshida, S (reprint author), Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. OI Reinhold, Carlos/0000-0003-0100-4962 NR 34 TC 32 Z9 32 U1 1 U2 1 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 1999 VL 60 IS 2 BP 1113 EP 1123 DI 10.1103/PhysRevA.60.1113 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900050 ER PT J AU Macek, JH Ovchinnikov, SY Solov'ev, EA AF Macek, JH Ovchinnikov, SY Solov'ev, EA TI Energy and angular distributions of detached electrons in a solvable model of ion-atom collisions SO PHYSICAL REVIEW A LA English DT Article ID SADDLE-POINT ELECTRONS; POTENTIALS; IONIZATION; EMISSION AB Electron energy and angular distributions are computed for a model of atom-negative-ion collisions. In this model, electron-atom interactions are represented by zero-range potentials in an approximation where two identical atoms move along straight-line classical trajectories in head-on collisions. Analytic expressions for the ionization amplitudes are interpreted in terms of Sturmian eigenvalues and eigenfunctions. At high velocity, the computed distributions exhibit direct excitation and continuum capture cusps in addition to the binary encounter ridge. At low velocities, a single feature corresponding to an electron distribution centered midway between the target and projectile emerges. For initial conditions corresponding to gerade symmetry a single broad peak appears, while for ungerade symmetry there is a node at the midpoint so that the peak splits into two parts. It is confirmed that the advanced adiabatic approximation gives an accurate description of the ungerade distribution at low and intermediate velocities. [S1050-2947(99)05408-6]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Macedonian Acad Sci & Arts, Res Ctr Energy & Informat, Skopje 91000, Macedonia. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Macek, JH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RI Ovchinnikov, Serguei/C-4994-2014 NR 28 TC 15 Z9 15 U1 1 U2 1 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 1999 VL 60 IS 2 BP 1140 EP 1152 DI 10.1103/PhysRevA.60.1140 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900053 ER PT J AU Reisenfeld, DB Gardner, LD Janzen, PH Savin, DW Kohl, JL AF Reisenfeld, DB Gardner, LD Janzen, PH Savin, DW Kohl, JL TI Absolute cross section for Si2+(3s(2) S-1 -> 3s3p P-1) electron-impact excitation SO PHYSICAL REVIEW A LA English DT Article ID 3S(2) S-1->3S3P P-3; III LINE RATIOS; SI-III; NEAR-THRESHOLD; DIELECTRONIC RECOMBINATION; RESONANCE STRUCTURE; EXPERIMENTAL APPARATUS; DETECTION EFFICIENCY; MICROCHANNEL PLATES; 2S-2P EXCITATION AB We have measured the absolute cross section for electron-impact excitation (EIE) of Si2+(3s(2 1)S --> 3s3p P-1) from energies below threshold to 11 eV above. A beams modulation technique with inclined electron and ion beams was used. Radiation at 120.7 nm from the excited ions was detected using an absolutely calibrated optical system. The fractional population of the Si2+(3s3p P-3 degrees) metastable state in the incident ion beam was determined to be 0.210 +/- 0.018 (1.65 sigma). The data have been corrected for contributions to the signal from radiative decay following excitation from the metastable state to 3s3p P-1 and 3p(2) P-3, and excitation from the ground stare to levels above the 3s3p Ip level. The experimental 0.56 +/- 0.08-eV energy spread allowed us to resolve complex resonance structure throughout the studied energy range. At the reported +/- 14% total experimental uncertainty level (1.65 sigma), the measured structure acid absolute scale of the cross section are in good agreement with 12-state close-coupling R-matrix calculations. [S1050-2947 (99)06008-4]. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Reisenfeld, DB (reprint author), Univ Calif Los Alamos Natl Lab, M-S-D466, Los Alamos, NM 87545 USA. RI Savin, Daniel/B-9576-2012; Reisenfeld, Daniel/F-7614-2015 OI Savin, Daniel/0000-0002-1111-6610; NR 70 TC 10 Z9 11 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 1999 VL 60 IS 2 BP 1153 EP 1164 DI 10.1103/PhysRevA.60.1153 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900054 ER PT J AU Lamoreaux, SK AF Lamoreaux, SK TI Feeble magnetic fields generated by thermal charge fluctuations in extended metallic conductors: Implications for electric-dipole moment experiments SO PHYSICAL REVIEW A LA English DT Article ID HG-199; LIMIT AB A simple formulation for calculating the magnetic field external to an extended nonpermeable conducting body due to thermal current fluctuations within the body is developed, and is applied to a recent experimental search for the atomic electric-dipole moment (EDM) of Hg-199. It is shown that the thermal fluctuation field is only slightly smaller in magnitude than other noise sources in that experiment. The formulation is extended to permeable bodies, and the implications for general EDM experiments are discussed. [S1050-2947(99)10408-6]. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. RP Lamoreaux, SK (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, MS H803, Los Alamos, NM 87545 USA. NR 10 TC 8 Z9 8 U1 0 U2 1 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 1999 VL 60 IS 2 BP 1717 EP 1720 DI 10.1103/PhysRevA.60.1717 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900119 ER PT J AU Kwiat, PG Waks, E White, AG Appelbaum, I Eberhard, PH AF Kwiat, PG Waks, E White, AG Appelbaum, I Eberhard, PH TI Ultrabright source of polarization-entangled photons SO PHYSICAL REVIEW A LA English DT Article ID PARAMETRIC DOWN-CONVERSION; BELL INEQUALITIES; EXPERIMENTAL REALIZATION; LOCAL REALISM; VIOLATION; STATES; INTERFEROMETRY; COMMUNICATION; THEOREM; PAIRS AB Using the process of spontaneous parametric down-conversion in a two-crystal geometry, we have generated a source of polarization-entangled photon pairs that is more than ten times brighter, per unit of pump power, than previous sources, with another factor of 30 to 75 expected to be readily achievable. We have measured a high level of entanglement between photons emitted over a relatively large collection angle, and over a 10-nm bandwidth. As a demonstration of the source capabilities, we obtained a 242-sigma violation of Bell's inequalities in less than three minutes, and observed near-perfect photon correlations when the collection efficiency was reduced. In addition, both the degree of entanglement and the state purity should be readily tunable. [S1050-2947(99)50108-X]. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Kwiat, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, P-23, Los Alamos, NM 87545 USA. RI Appelbaum, Ian/E-4056-2012; White, Andrew/A-1088-2009 OI White, Andrew/0000-0001-9639-5200 NR 38 TC 530 Z9 544 U1 7 U2 41 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 1999 VL 60 IS 2 BP R773 EP R776 DI 10.1103/PhysRevA.60.R773 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900012 ER PT J AU Kennedy, BJ Howard, CJ Chakoumakos, BC AF Kennedy, BJ Howard, CJ Chakoumakos, BC TI High-temperature phase transitions in SrHfO3 SO PHYSICAL REVIEW B LA English DT Article ID SRRUO3 AB The crystal structure of SrHfO3 has been studied at high temperatures using powder neutron diffraction and the Rietveld method. From 300 K to approximately 670 K the structure of SrHfO3 is orthorhombic (Pnma). By 870 K the material adopts a second orthorhombic structure (Cmcm). The material then undergoes a further phase transition and is tetragonal (I4/mcm) from similar to 1000 to 1353 K. At higher temperatures (>1360 K) the structure is the ideal cubic perovskite (Pm (3) over bar m). The angle of rotation of the oxygen octahedron in the tetragonal phase is taken as the order parameter and its temperature variation is consistent with a second order phase transition. [S0163-1829(99)06229-3]. C1 Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Kennedy, BJ (reprint author), Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. RI Howard, Christopher/B-5138-2009; Chakoumakos, Bryan/A-5601-2016; OI Chakoumakos, Bryan/0000-0002-7870-6543; Kennedy, Brendan/0000-0002-7187-4579 NR 16 TC 113 Z9 114 U1 4 U2 29 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 5 BP 2972 EP 2975 DI 10.1103/PhysRevB.60.2972 PG 4 WC Physics, Condensed Matter SC Physics GA 225VH UT WOS:000081986300004 ER PT J AU Kang, BW Wu, JZ Gapud, AA Kang, WN Christen, DK Kerchner, R AF Kang, BW Wu, JZ Gapud, AA Kang, WN Christen, DK Kerchner, R TI Glassy behavior of vortex liquid in high-T-c superconducting thin films SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; ACTIVATED FLUX MOTION; SINGLE-CRYSTALS; II SUPERCONDUCTORS; MAGNETIC-FIELDS; HALL RESISTIVITIES; PHASE-TRANSITION; YBA2CU3O7-DELTA; STATE; CREEP AB In the presence of pinning, two vortex-liquid regions were identified: a glassy liquid (GL), where vortices remain coupled in the ab plane as manifested by non-Ohmic resistivity, and a regular liquid (RL), where resistivity becomes Ohmic as vortices become decoupled. The field dependence of the Hail angle is linear in the RL and nonlinear in the GL. Since the boundary (H-k-T) between the GL and RL shifts to higher temperatures and magnetic fields as pinning increases, vortices may be decoupled and depinned simultaneously when the H-k-T line merges into the vortex depinning line. [S0163-1829(99)08429-5]. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Kang, BW (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. EM bwkang@ukans.edu OI Gapud, Albert/0000-0001-9048-9230 NR 29 TC 2 Z9 2 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 5 BP 3088 EP 3091 DI 10.1103/PhysRevB.60.3088 PG 4 WC Physics, Condensed Matter SC Physics GA 225VH UT WOS:000081986300034 ER PT J AU Zherlitsyn, S Luthi, B Wolf, B Sarrao, JL Fisk, Z Zlatic, V AF Zherlitsyn, S Luthi, B Wolf, B Sarrao, JL Fisk, Z Zlatic, V TI Ultrasonic study of the mixed-valence system YbIn1-xAgxCu4 SO PHYSICAL REVIEW B LA English DT Article ID PHASE-TRANSITION; MAGNETIC-FIELD; YBINCU4; YBXIN1-XCU2; PRESSURE; NEUTRON; YBXCU4; MODEL AB We report ultrasonic investigation of the mixed-valence compounds YbIn1-xAgxCu4 for the different silver concentrations x = 0, 0.2, 0.25, 0.3. This study enables us to characterize the coupling of the Yb ions with the lattice as a function of temperature, magnetic field, and silver concentration. For x = 0 and 0.2 the system demonstrates pronounced first-order phase transition with the abrupt change in the different elastic moduli. For the higher silver concentrations we have observed rather smooth behavior of the elastic constants which is typical for a continuous phase transition. The critical temperature and the size of the anomaly in the bulk modulus at the phase transition changes linearly with silver concentration. External magnetic field shifts the transition to lower temperatures in accordance with previous investigations. Numerical calculations of the bulk modulus and the magnetic susceptibility have been performed in the frame of the promotional Ramirez-Falicov model. The results obtained demonstrate qualitative and quantitative agreement with the experimental data. [S0163-1829(99)06029-4]. C1 Univ Frankfurt, Inst Phys, D-60054 Frankfurt, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Florida State Univ, Tallahassee, FL 32306 USA. Inst Phys, Zagreb, Croatia. RP Zherlitsyn, S (reprint author), Univ Frankfurt, Inst Phys, Robert Mayer Str 2-4, D-60054 Frankfurt, Germany. NR 30 TC 18 Z9 18 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 5 BP 3148 EP 3153 DI 10.1103/PhysRevB.60.3148 PG 6 WC Physics, Condensed Matter SC Physics GA 225VH UT WOS:000081986300043 ER PT J AU Mizel, A Benedict, LX Cohen, ML Louie, SG Zettl, A Budraa, NK Beyermann, WP AF Mizel, A Benedict, LX Cohen, ML Louie, SG Zettl, A Budraa, NK Beyermann, WP TI Analysis of the low-temperature specific heat of multiwalled carbon nanotubes and carbon nanotube ropes SO PHYSICAL REVIEW B LA English DT Article ID CAPACITY; DYNAMICS AB We analyze specific-heat measurements in the temperature range 1 Cu 3d charge transfer energy. In the O 1s region, a smaller bond length between Ba and Cu-O planar oxygen is found to correlate with a lower binding energy for the signal associated with Cu-O bonding, most likely resulting from the increased polarization screening by Ba2+ ions. For samples near optimum doping, maximum T-c is observed to occur when the Tl 4f(7/2) binding energy is near 117.9 eV, which is near the middle of the range of values observed for Tl cuprates. Higher Tl 4f(7/2) binding energies, corresponding to formal oxidation states nearer Tl1+, are also found to correlate with longer bond lengths between Ba and Tl-O planar oxygen, and with higher binding energies of the O is signal associated with Tl-O bonding. [S0163-1829(99)12729-2]. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SUNY Buffalo, Dept Chem, Mat Synth Lab, Buffalo, NY 14260 USA. RP Vasquez, RP (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. EM richard.vazquez@jpl.nasa.gov RI Ren, Zhifeng/B-4275-2014 NR 53 TC 12 Z9 12 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 6 BP 4309 EP 4319 DI 10.1103/PhysRevB.60.4309 PG 11 WC Physics, Condensed Matter SC Physics GA 226AA UT WOS:000081997100084 ER PT J AU Ovchinnikov, YN Wolf, SA Kresin, VZ AF Ovchinnikov, YN Wolf, SA Kresin, VZ TI Inhomogeneity of the superconducting state and consequent diamagnetism above T-c: Application to the cuprates SO PHYSICAL REVIEW B LA English DT Article ID CRITICAL-FIELD; TL2BA2CUO6+DELTA; TEMPERATURE AB The inhomogeneity of a superconducting system gives rise to an interesting situation when at T > T-c(res) (T-c(res) is characterized by a relatively sharp resistive transition) one can observe an anomalously large diamagnetic moment. Here we focus on the case when the sample can be described as containing a nonuniform distribution of magnetic impurities and, as a consequence, by an inhomogeneous distribution of critical temperatures. The analysis is in good agreement with experimental data on overdoped cuprates. [S0163-1829(99)01030-9]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, Landau Inst Theoret Phys, Moscow 11733V, Russia. USN, Res Lab, Washington, DC 20375 USA. RP Ovchinnikov, YN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Wolf, Stuart/A-7513-2009 NR 19 TC 27 Z9 27 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 6 BP 4329 EP 4333 DI 10.1103/PhysRevB.60.4329 PG 5 WC Physics, Condensed Matter SC Physics GA 226AA UT WOS:000081997100086 ER PT J AU Dong, J Musfeldt, JL Schlueter, JA Williams, JM Nixon, PG Winter, RW Gard, GL AF Dong, J Musfeldt, JL Schlueter, JA Williams, JM Nixon, PG Winter, RW Gard, GL TI Optical properties of beta ''-(ET)(2)SF5CH2CF2SO3: A layered molecular superconductor with large discrete counterions SO PHYSICAL REVIEW B LA English DT Article ID PRESSURE ORGANIC SUPERCONDUCTOR; CHARGE-TRANSFER SALTS; BEDT-TTF; INFRARED CONDUCTIVITY; FERMI-SURFACE; ELECTRON; CONDUCTORS; SYSTEMS; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; SPECTROSCOPY AB We report the polarized infrared and optical reflectance of beta "-(ET)(2)SF5CH2CF2SO3 as a function of temperature. This fully organic superconductor displays weakly metallic behavior over the entire temperature range of our investigation. The electronic properties present several unusual features including the lack of a conventional free carrier (Drude) response at low temperature, infrared localization phenomena, and an unexpected temperature dependence of the oscillator strength. Similar behavior is observed in other beta and beta " superconductors above T-c, suggesting that this class of compounds is very close to a metal --> insulator transition where electronic correlations are important and the Drude response carries very little spectral weight. Vibronic features increase in intensity with decreasing temperature in the infrared, as expected. The temperature dependence of key anion vibrational modes are discussed in terms of intermolecular hydrogen bonding within the anion pocket. [S0163-1829(99)04330-1]. C1 SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Dong, J (reprint author), SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. NR 64 TC 26 Z9 26 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 6 BP 4342 EP 4350 DI 10.1103/PhysRevB.60.4342 PG 9 WC Physics, Condensed Matter SC Physics GA 226AA UT WOS:000081997100088 ER PT J AU Koshelev, AE Bulaevskii, LN AF Koshelev, AE Bulaevskii, LN TI Fluctuation broadening of the plasma resonance line in the vortex liquid state of layered superconductors SO PHYSICAL REVIEW B LA English DT Article ID JOSEPHSON-PLASMA; BI2SR2CACU2O8+DELTA; PHASE; EXCITATION; MODE AB The Josephson plasma resonance (JPR) provides a sensitive probe of vortex states in layered superconductors. We demonstrate that in the case of weak damping in the liquid phase, broadening of the JPR line is caused mainly by random Josephson coupling arising from the density fluctuations of pancake vortices. In this case the JPR line has the universal shape, which is determined only by parameters of the superconductors and temperature. This mechanism gives a natural explanation for the experimentally observed asymmetric lineshape. The tail at high frequencies arises due to mixing of the propagating plasma modes by random Josephson coupling, while the tail at small frequencies is caused by the localized plasma modes originating from a rare fluctuation suppression of the Josephson coupling in large areas. [S0163-1829(99)51130-2]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Koshelev, AE (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 15 TC 10 Z9 10 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 1999 VL 60 IS 6 BP R3743 EP R3746 DI 10.1103/PhysRevB.60.R3743 PG 4 WC Physics, Condensed Matter SC Physics GA 226AA UT WOS:000081997100012 ER PT J AU Chemakin, I Cianciolo, V Cole, BA Fernow, R Frawley, A Gilkes, M Gushue, S Hartouni, EP Hiejima, H Justice, M Kang, JH Kirk, H Maeda, N McGrath, RL Mioduszewski, S Morrison, D Moulson, M Namboodiri, MN Rai, G Read, K Remsberg, L Rosati, M Shin, Y Soltz, RA Sorensen, S Thomas, J Torun, Y Winter, D Yang, X Zajc, WA Zhang, Y AF Chemakin, I Cianciolo, V Cole, BA Fernow, R Frawley, A Gilkes, M Gushue, S Hartouni, EP Hiejima, H Justice, M Kang, JH Kirk, H Maeda, N McGrath, RL Mioduszewski, S Morrison, D Moulson, M Namboodiri, MN Rai, G Read, K Remsberg, L Rosati, M Shin, Y Soltz, RA Sorensen, S Thomas, J Torun, Y Winter, D Yang, X Zajc, WA Zhang, Y TI Measuring centrality with slow protons in proton-nucleus collisions at 18 GeV/c SO PHYSICAL REVIEW C LA English DT Article ID HIGH-ENERGY; MULTIPARTICLE PRODUCTION; NE INTERACTIONS; GEV-C; MULTIPLICITY; PARTICLES; NUMBER; MODEL; GOLD AB Experiment E910 has measured slow protons and deuterons from collisions of 18 GeV/c protons with Be, Cu, and Au targets at the BNL AGS. These correspond to the "grey tracks" first observed in emulsion experiments. We report on their momentum and angular distributions and investigate their use in measuring the centrality of a collision, as defined by the mean number of projectile-nucleon interactions. The relation between the measured N-grey and the mean number of interactions <(nu)over bar>(N-grey) is studied using several simple models, one newly proposed, as well as the RQMD event generator. RQMD is shown to reproduce the N-grey distribution, and exhibits a dependence of N-grey on centrality that is similar to the behavior of the simple models. We find a strong linear dependence of N-grey on nu, with a constant of proportionality that varies with target. For the Au target, we report a relative systematic error for extracting <(nu)over bar>(nu)over bar>(N-grey) that lies between 10 and 20 % over all N-grey. [S0556-2813(99)02508-X]. C1 Columbia Univ, New York, NY 10027 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Nevis Labs, Irvington, NY 10533 USA. Florida State Univ, Tallahassee, FL 32306 USA. Iowa State Univ, Ames, IA 50010 USA. Kent State Univ, Kent, OH 44242 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Div Phys, Livermore, CA 94550 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Univ Tennessee, Knoxville, TN 37996 USA. Yonsei Univ, Seoul 120749, South Korea. RP Chemakin, I (reprint author), Columbia Univ, New York, NY 10027 USA. NR 29 TC 19 Z9 19 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024902 DI 10.1103/PhysRevC.60.024902 PG 12 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700044 ER PT J AU del Campo, JG Shapira, D McConnell, J Gross, CJ Stracener, DW Madani, H Chavez, E Ortiz, ME AF del Campo, JG Shapira, D McConnell, J Gross, CJ Stracener, DW Madani, H Chavez, E Ortiz, ME TI Preequilibrium emission observed in the correlation between light particles and evaporation residues for the Kr-84+Al-27 system SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-IONS; MEV-NUCLEON; MEV/NUCLEON; FRAGMENTS; FUSION; COINCIDENCES; COLLISIONS; ENERGY; ONSET AB Evaporation residues (ER) of Z = 34-42 were measured in coincidence with emitted protons, deuterons, tritons, and alpha particles for the reaction Kr-84+Al-27 at a Kr-84 bombarding energy of 1260 MeV. Our study demonstrates the presence of a strong preequilibrium component in the reaction yield. The assumption of a forward center-of-mass angular distribution for the emission of energetic protons and alpha following full momentum transfer, gives the best description of the observed experimental data. This description differs substantially from the one provided by prevailing models of incomplete fusion. [S0556-2813(99)50108-8]. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico. RP del Campo, JG (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 18 TC 5 Z9 5 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 021601 PG 5 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700005 ER PT J AU Gaulard, CV Riedel, CM Comfort, JR Amann, JF Beddo, ME Boudrie, RL Burleson, GR Cole, PL Craig, KK Espy, MA Isenhower, LD Kasprzyk, TE Knight, KR Morris, CL Penttila, S Rigsby, D Sadler, ME Six, E Spinka, HM Supek, I Wagner, GJ Zhao, Q AF Gaulard, CV Riedel, CM Comfort, JR Amann, JF Beddo, ME Boudrie, RL Burleson, GR Cole, PL Craig, KK Espy, MA Isenhower, LD Kasprzyk, TE Knight, KR Morris, CL Penttila, S Rigsby, D Sadler, ME Six, E Spinka, HM Supek, I Wagner, GJ Zhao, Q TI Analyzing powers for the pi(-)(p)over-right-arrow ->pi(0)n reaction across the Delta(1232) resonance SO PHYSICAL REVIEW C LA English DT Article ID ELASTIC-SCATTERING; POLARIZED TARGETS; CHARGE-EXCHANGE; PI; BREAKING AB High quality analyzing powers for the pi(-) (p) over right arrow --> pi(0)n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing pi N single-charge-exchange database for energies ranging from 10 to 230 MeV, with 36 new analyzing Powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the Delta(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon sigma term from the scattering amplitudes. [3S0556-2813(99)02408-5]. C1 Arizona State Univ, Tempe, AZ 85287 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. George Washington Univ, Washington, DC 20052 USA. Univ Minnesota, Minneapolis, MN 55455 USA. Abilene Christian Univ, Abilene, TX 79699 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Rudjer Boskovic Inst, Zagreb 41000, Croatia. Univ Tubingen, D-72076 Tubingen, Germany. RP Gaulard, CV (reprint author), Ist Nazl Fis Nucl, Lab Nazl Frascati, Via Enrico Fermi 40, I-00044 Frascati, Italy. NR 45 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024604 PG 13 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700036 ER PT J AU Glendenning, NK Schaffner-Bielich, J AF Glendenning, NK Schaffner-Bielich, J TI First order kaon condensate SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; NEUTRON-STAR MATTER; MEAN-FIELD THEORY; NUCLEAR-MATTER; QUARK MATTER; PHASE; EQUATION; HYPERNUCLEI; STRANGENESS; HYPERONS AB First order Bose condensation in asymmetric nuclear matter and in neutron stars is studied, with particular reference to kaon condensation. We demonstrate explicitly why the Maxwell construction fails to assure equilibrium in multicomponent substances. Gibbs conditions and conservation laws require that for phase equilibrium, the charge density must have opposite sign in the two phases of isospin asymmetric nuclear matter. The mixed phase will therefore form a Coulomb lattice with the rare phase occupying lattice sites in the dominant phase. Moreover, the kaon condensed phase differs from the normal phase, not by the mere presence of kaons in the first. but also by a difference in the nucleon effective masses. The mixed phase region, which occupies a large radial extent amounting to some kilometers in our model neutron stars, is thus highly heterogeneous. It should be particularly interesting in connection with the pulsar glitch phenomenon as well as transport properties. [S0556-2813(99)04507-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Inst Nucl & Particle Phys, Berkeley, CA 94720 USA. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Glendenning, NK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, MS 70A-3307, Berkeley, CA 94720 USA. NR 42 TC 158 Z9 159 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 025803 DI 10.1103/PhysRevC.60.025803 PG 13 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700058 ER PT J AU Lehmann, A Androic, D Backenstoss, G Bosnar, D Dooling, T Furic, M Gram, PAM Gregory, NK Hoffart, A Ingram, CHQ Klein, A Koch, K Kohler, J Kotlinski, B Kroedel, M Kyle, G Mateos, AO Michaelian, K Petkovic, T Planinic, M Redwine, RP Rowntree, D Simicevic, N Trezeciak, R Ullrich, H Weyer, HJ Wildi, M Wilson, KE AF Lehmann, A Androic, D Backenstoss, G Bosnar, D Dooling, T Furic, M Gram, PAM Gregory, NK Hoffart, A Ingram, CHQ Klein, A Koch, K Kohler, J Kotlinski, B Kroedel, M Kyle, G Mateos, AO Michaelian, K Petkovic, T Planinic, M Redwine, RP Rowntree, D Simicevic, N Trezeciak, R Ullrich, H Weyer, HJ Wildi, M Wilson, KE TI Total cross sections of the charge exchange reaction (pi(+,)pi(0)) on H-2, He-3, and He-4 across the Delta(1232) resonance SO PHYSICAL REVIEW C LA English DT Article ID ELASTIC-SCATTERING DATA; QUASI-FREE SCATTERING; INELASTIC-SCATTERING; PION ABSORPTION; DEUTERIUM; BREAKUP; NUCLEI AB Results from a 4 pi solid angle measurement of the inclusive reaction (pi(+), pi(0)) on H-2, He-3, and He-4 at incident pion energies of Tpi+ = 70, 118, 162, 239, and 330 MeV are presented. The single charge exchange total cross sections were determined, and are compared to previous results and simple models of pi-few-nucleon interactions. On the helium isotopes a strong damping of the cross sections in the Delta(1232) energy region is observed. Total cross sections of the breakup reaction pi(+) + H-2 --> pi(+) pn are also given. [S0556-2813(99)00708-6]. C1 Univ Basel, CH-4056 Basel, Switzerland. Univ Karlsruhe, D-76128 Karlsruhe, Germany. Los Alamos Meson Phys Facil, Los Alamos, NM 87545 USA. MIT, Cambridge, MA 02139 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Univ Zagreb, HR-10000 Zagreb, Croatia. RP Lehmann, A (reprint author), Univ Basel, CH-4056 Basel, Switzerland. RI Planinic, Mirko/E-8085-2012; Androic, Darko/A-7482-2008 NR 45 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024603 PG 9 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700035 ER PT J AU Mantica, PF Papantonakis, MR Butler-Moore, K Deng, JK Hamilton, JH Hamilton, WD Kormicki, J Lahamer, A Ma, WC Ramayya, AV AF Mantica, PF Papantonakis, MR Butler-Moore, K Deng, JK Hamilton, JH Hamilton, WD Kormicki, J Lahamer, A Ma, WC Ramayya, AV TI Nuclear orientation of Tc-96 SO PHYSICAL REVIEW C LA English DT Article ID INTERACTING-BOSON MODEL; MIXED-SYMMETRY STATES; MO ISOTOPES AB The decay of Tc-96(g) has been studied using low-temperature nuclear orientation. Multipole mixing ratios have been deduced for several transitions in the daughter nucleus Mo-96 by measuring gamma-ray anisotropies following the decay of the oriented Tc-96 nuclei. These new mixing ratios are compared with those determined from previous measurements in light of the possible presence of a low-energy 6(+) mixed-symmetry state in Mo-96. [S0556-2813(99)00508-7]. C1 Oak Ridge Inst Sci & Educ, UNISOR, Oak Ridge, TN 37831 USA. Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA. Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Berea Coll, Dept Phys, Berea, KY 40404 USA. Univ Sussex, Dept Phys, Brighton BN1 9QH, E Sussex, England. RP Mantica, PF (reprint author), Oak Ridge Inst Sci & Educ, UNISOR, Oak Ridge, TN 37831 USA. RI Papantonakis, Michael/G-3888-2012 NR 16 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 027301 DI 10.1103/PhysRevC.60.027301 PG 4 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700061 ER PT J AU Schertler, K Leupold, S Schaffner-Bielich, J AF Schertler, K Leupold, S Schaffner-Bielich, J TI Neutron stars and quark phases in the Nambu-Jona-Lasinio model SO PHYSICAL REVIEW C LA English DT Article ID HYBRID STARS; FREE-ENERGY; MATTER; NUCLEI; QCD; THERMODYNAMICS; TEMPERATURE; SUPERNOVA; EQUATION; HADRONS AB We study the possible existence of deconfined quark matter in the interior of neutron stars using the Nambu-Jona-Lasinio model to describe the quark phase. We find that typical neutron stars with masses around 1.4 solar masses do not possess any deconfined quark matter in their center. This can be traced back to the property of the NJL model which suggests a large constituent strange quark mass over a wide range of densities. [S0556-2813(99)01008-0]. C1 Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Schertler, K (reprint author), Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany. EM klaus.schertler@theo.physik.uni-giessen.de NR 46 TC 63 Z9 65 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 025801 DI 10.1103/PhysRevC.60.025801 PG 11 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700056 ER PT J AU Smolanczuk, R AF Smolanczuk, R TI Production of superheavy elements SO PHYSICAL REVIEW C LA English DT Article ID NUCLEI; DECAY AB We propose a discovery experiment for production and identification of isotopes of unobserved elements up to element 119. We predict decay properties of nuclear systems that might be obtained in this experiment and discuss posibilities of identification of new elements on the basis of the calculated properties. [S0556-2813(99)50308-1]. C1 Soltan Inst Nucl Studies, Nucl Theory Dept, PL-00681 Warsaw, Poland. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Smolanczuk, R (reprint author), Soltan Inst Nucl Studies, Nucl Theory Dept, Hoza 69, PL-00681 Warsaw, Poland. EM smolan@fuw.edu.pl NR 21 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 021301 DI 10.1103/PhysRevC.60.021301 PG 3 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700001 ER PT J AU Stoks, VGJ Lee, TSH AF Stoks, VGJ Lee, TSH TI Strange hadron matter and SU(3) symmetry SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEAR-MATTER; QUARK-MATTER; DROPLETS; SEPARATION AB We calculate saturation curves for strange hadron matter using recently constructed baryon-baryon potentials which are constrained by SU(3) symmetry. All possible interaction channels within the baryon octet (consisting of N, Lambda, Sigma, and Xi) an considered. It is found that a small Lambda fraction in nuclear matter slightly increases binding, but that larger fractions (>10%) rapidly cause a decrease. Charge-neutral {N, Lambda, Xi} systems, with equal densities for nucleons and cascades, an only very weakly bound. The dependence of the binding energies on the strangeness per baryon, f(s), is predicted for various {N, Lambda, Xi} and {N, Lambda, Sigma, Xi} systems. The implications of our results in relativistic heavy-ion collisions and the core of a dense star are discussed. We also discuss the differences between our results and previous hadron matter calculations. [S0556-2813(99)06108-7]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Adelaide, Ctr Subatom Struct Matter, Adelaide, SA 5005, Australia. RP Stoks, VGJ (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 31 TC 29 Z9 34 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024006 DI 10.1103/PhysRevC.60.024006 PG 9 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700015 ER PT J AU Voloshin, SA Koch, V Ritter, HG AF Voloshin, SA Koch, V Ritter, HG TI Event-by-event fluctuations in collective quantities SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; TEMPERATURE AB We discuss an event-by-event fluctuation analysis of particle production in heavy ion collisions. We compare different approaches to the evaluation of the event-by-event dynamical fluctuations in quantities defined on groups of particles, such quantities as mean transverse momentum, transverse momentum spectra slope, strength of anisotropic flow, etc. The direct computation of the dynamical fluctuations and the subevent method are discussed in more detail. We also show how the fluctuations in different variables can be related to each other. [S0556-2813(99)03508-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Voloshin, SA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Voloshin, Sergei/I-4122-2013 NR 19 TC 86 Z9 89 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024901 DI 10.1103/PhysRevC.60.024901 PG 7 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700043 ER PT J AU Zhao, Q Burleson, G Blanchard, S Chang, T Gibbs, W Haas, J Park, B Whitton, M Espy, M Dehnhard, D Larson, B O'Donnell, J Palarczyk, M Cummings, W Delheij, P Hausser, O Pasyuk, E Gostkin, M Amann, J Boudrie, R Riedel, C Morris, C Pentilla, S Swenson, D Tupa, D Comfort, J Gaulard, C Maeda, K Glass, G Supek, I AF Zhao, Q Burleson, G Blanchard, S Chang, T Gibbs, W Haas, J Park, B Whitton, M Espy, M Dehnhard, D Larson, B O'Donnell, J Palarczyk, M Cummings, W Delheij, P Hausser, O Pasyuk, E Gostkin, M Amann, J Boudrie, R Riedel, C Morris, C Pentilla, S Swenson, D Tupa, D Comfort, J Gaulard, C Maeda, K Glass, G Supek, I TI Measurements of asymmetries of pion single charge exchange on polarized He-3 at 200 MeV SO PHYSICAL REVIEW C LA English DT Article ID ELASTIC-SCATTERING; P-33 RESONANCE; ENERGY REGION; TRINUCLEON; C-13; RB AB Asymmetries for the (pi(-), pi(0)) reaction on polarized He-3 were measured using a 200-MeV pion beam at LAMPF. The pi(0)'s were detected with the neutral meson spectrometer in coincidence with the recoiling tritons. A recoil triton detector, consisting of scintillation-counter telescopes and a wire chamber, was used to measure the time-of-flight, energy loss, and direction of the tritons. The polarized gaseous He-3 target, developed at TRIUMF, was modified to run with two diode lasers; the polarization reached 65%. The asymmetries between theta(lab)=60 degrees and 105 degrees were found to be strongly angle dependent. The results are compared with theoretical calculations. [S0556-2813(99)02208-6]. C1 New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Tri Univ Meson Facil, Vancouver, BC V6T 2A3, Canada. Joint Inst Nucl Res Dubna, Moscow, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Arizona State Univ, Dept Phys, Tempe, AZ 85281 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 980, Japan. Univ Texas, Austin, TX 78712 USA. Rudjer Boskovic Inst, Zagreb, Croatia. RP Zhao, Q (reprint author), Univ Michigan, Ann Arbor, MI 48109 USA. NR 30 TC 0 Z9 0 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1999 VL 60 IS 2 AR 024001 PG 11 WC Physics, Nuclear SC Physics GA 226YX UT WOS:000082051700010 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF 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 Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chong, M Claes, D Clark, AR Cobau, WG Cochran, I Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R 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 Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, R Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW 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 Wood, DR Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF 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 Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chong, M Claes, D Clark, AR Cobau, WG Cochran, I Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R 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 Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, R Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW 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 Wood, DR Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A TI Search for bottom squarks in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW D LA English DT Article AB We report on a search for bottom squarks ((b) over tilde) produced in p (p) over bar collisions at root s = 1.8 TeV using the D circle divide detector at Fermilab. Bottom squarks are assumed to be produced in pairs and to decay to the lightest super-symmetric particle (LSP) and a b quark with a branching fraction of 100%. The LSP is assumed to be the lightest neutralino and stable. We set limits on the production cross section as a function of (b) over tilde mass and LSP mass. [S0556-2821(99)50313-1]. C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Inst High Energy Phys, Beijing 100039, Peoples R China. Univ Los Andes, Bogota, Colombia. Univ San Francisco Quito, Quito, Ecuador. Univ Grenoble 1, Inst Sci Nucl, IN2P3, CNRS, Grenoble, France. CEA Saclay, DAPNIA, Serv Phys Particules, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow, Russia. Moscow MV Lomonosov State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), NYU, New York, NY 10003 USA. RI Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016; Belyaev, Alexander/F-6637-2015; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Leflat, Alexander/D-7284-2012; Dudko, Lev/D-7127-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013 OI Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108; Belyaev, Alexander/0000-0002-1733-4408; Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; NR 14 TC 21 Z9 21 U1 0 U2 2 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 1 PY 1999 VL 60 IS 3 AR 031101 DI 10.1103/PhysRevD.60.031101 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300001 ER PT J AU Ambrogiani, M Bagnasco, S Baldini, W Bettoni, D Borreani, G Buzzo, A Calabrese, R Cester, R Dalpiaz, P Fan, X Garzoglio, G Gollwitzer, KE Hahn, A Jin, S Kasper, J Lasio, G Lo Vetere, M Luppi, E Maas, P Macri, M Mandelkern, M Marchetto, F Marinelli, M Marsh, W Martini, A Menichetti, E Mussa, R Obertino, MM Pallavicini, A Pastrone, N Patrignani, C Pedlar, TK Peoples, J Pordes, S Robutti, E Rosen, J Rumerio, P Santroni, A Savrie, M Schultz, J Seth, KK Stancari, G Stancari, M Streets, J Tomaradze, A Werkema, S Zioulas, G AF Ambrogiani, M Bagnasco, S Baldini, W Bettoni, D Borreani, G Buzzo, A Calabrese, R Cester, R Dalpiaz, P Fan, X Garzoglio, G Gollwitzer, KE Hahn, A Jin, S Kasper, J Lasio, G Lo Vetere, M Luppi, E Maas, P Macri, M Mandelkern, M Marchetto, F Marinelli, M Marsh, W Martini, A Menichetti, E Mussa, R Obertino, MM Pallavicini, A Pastrone, N Patrignani, C Pedlar, TK Peoples, J Pordes, S Robutti, E Rosen, J Rumerio, P Santroni, A Savrie, M Schultz, J Seth, KK Stancari, G Stancari, M Streets, J Tomaradze, A Werkema, S Zioulas, G TI Measurements of the magnetic form factor of the proton in the timelike region at large momentum transfer SO PHYSICAL REVIEW D LA English DT Article ID QUANTUM CHROMODYNAMICS; EXCLUSIVE PROCESSES; FERMILAB; EXPERIMENT-835; THRESHOLD; TARGET AB The cross section for the reaction (p) over bar p --> e (+) e (-) has been measured at s = 8.8, 10.8, 12.4, 13.1, and 14.4 GeV2 by Fermilab experiment E835. A non-magnetic spectrometer is used to identify the e (+) e (-) final states generated by the antiproton beam intersecting an internal hydrogen gas jet target. From the analysis of the 144 observed events, new high-precision measurements of the proton magnetic form factor for timelike momentum transfers are obtained, [80556-2821(99)03013-1]. C1 Ist Nazl Fis Nucl, I-44100 Ferrara, Italy. Univ Ferrara, I-44100 Ferrara, Italy. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Ist Nazl Fis Nucl, I-16146 Genoa, Italy. Univ Genoa, I-16146 Genoa, Italy. Univ Calif Irvine, Irvine, CA 92697 USA. Northwestern Univ, Evanston, IL 60208 USA. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, I-10125 Turin, Italy. RP Ist Nazl Fis Nucl, I-44100 Ferrara, Italy. RI Cafagna, Francesco/A-9299-2010; Castellano, Marcello/J-3428-2012; Aramo, Carla/D-4317-2011; Rastelli, Armando/E-6955-2012; giglietto, nicola/I-8951-2012; Spurio, Maurizio/G-4170-2012; Patrignani, Claudia/C-5223-2009; Luppi, Eleonora/A-4902-2015; Calabrese, Roberto/G-4405-2015; Lo Vetere, Maurizio/J-5049-2012; Lamanna, Ernesto/C-7658-2012; Barbarino, Giancarlo/L-2559-2015; Martello, Daniele/J-3131-2012; Mazziotta, Mario /O-8867-2015; Guarino, Fausto/I-3166-2012 OI Cafagna, Francesco/0000-0002-7450-4784; Castellano, Marcello/0000-0002-4211-2903; Rastelli, Armando/0000-0002-1343-4962; giglietto, nicola/0000-0002-9021-2888; Patrignani, Claudia/0000-0002-5882-1747; Luppi, Eleonora/0000-0002-1072-5633; Calabrese, Roberto/0000-0002-1354-5400; Lo Vetere, Maurizio/0000-0002-6520-4480; Lamanna, Ernesto/0000-0002-7844-8230; Barbarino, Giancarlo/0000-0001-9253-3397; Martello, Daniele/0000-0003-2046-3910; Mazziotta, Mario /0000-0001-9325-4672; Guarino, Fausto/0000-0003-1427-9885 NR 27 TC 136 Z9 138 U1 0 U2 8 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 1 PY 1999 VL 60 IS 3 AR 032002 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300007 ER PT J AU Bar-Shalom, S Eilam, G Soni, A AF Bar-Shalom, S Eilam, G Soni, A TI Flavor changing top decay t -> c(nu)over-tilde or (nu)over-tilde -> t(c)over-bar in the MSSM without R parity SO PHYSICAL REVIEW D LA English DT Article ID STANDARD MODEL; NEUTRAL CURRENTS; QUARK DECAYS; CP VIOLATION; RARE DECAYS; T(C)OVER-BAR-E(+)E(-); T->CW(+)W(-) AB Widths for the new flavor-changing top quark decay t --> c<(nu)over tilde> or for the reversed sneutrino decay <(nu)over tilde> --> t (c) over bar are calculated in the minimal supersymmetric standard model without R-parity conservation. For large tan beta, e.g., tan beta similar to m(t)/m(b) similar to 40, Br(t --> c<(nu)over tilde>) > 10(-5) or Br(<(nu)over tilde> --> t (c) over bar) > 10(-6) in a relatively wide range of the supersymmetric parameter space as long as there is more than one nonzero R-parity violating coupling. In the best cases, with a typical squark mass around 100 GeV, we find that Br(t --> c<(nu)over tilde>) similar to 10(-4) - 10(-3) or Br(<(nu)over tilde> --> t (c) over bar) similar to 10(-5) - 10(-4). For tan beta-O(1) the corresponding branching ratios for both top or sneutrino decays are too small to be measured at the CERN Large Hadron Collider (LHC). Therefore, the decays t --> c<(nu)over tilde> or <(nu)over tilde> --> t (c) over bar appear to be sensitive to tan beta and may be detected at the LHC. The branching ratios of the corresponding decays to an up quark instead of a charm quark, e.g.,t --> u<(nu)over tilde> or <(nu)over tilde> --> t (u) over bar, may also be similar. [S0556-2821(99)04911-5]. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Technion Israel Inst Technol, Dept Phys, IL-32000 Haifa, Israel. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 30 TC 14 Z9 14 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 1 PY 1999 VL 60 IS 3 AR 035007 DI 10.1103/PhysRevD.60.035007 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300056 ER PT J AU Bass, SD Brodsky, SJ Schmidt, I AF Bass, SD Brodsky, SJ Schmidt, I TI Gluon virtuality and heavy sea-quark contributions to the spin-dependent g1 structure function SO PHYSICAL REVIEW D LA English DT Article ID PERTURBATIVE QUANTUM CHROMODYNAMICS; POLARIZED PARTON DISTRIBUTIONS; STRUCTURE-FUNCTION G(1)(N); INELASTIC MUON SCATTERING; NUCLEON SPIN; CHIRAL SYMMETRY; ASYMMETRY ZERO; PROTON; LEPTOPRODUCTION; DEUTERON AB We analyze the quark mass dependence of photon gluon fusion in polarized deep inelastic scattering for both the intrinsic and extrinsic gluon distributions of the nucleon. We calculate the effective number of flavors for each of the heavy and light quark photon gluon fusion contributions to the first moment of the spin-dependent structure function g(1)(x). [S0556-2821(99)01115-7]. C1 Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Tecn Federico Santa Maria, Dept Fis, Valparaiso, Chile. RP Tech Univ Munich, Dept PhysD85747, Garching, Germany. EM Steven.Bass@mpi-hd.mpg.de; sjbth@slac.stanford.edu; ischmidt@is.utfsm.cl RI Schmidt, Ivan/J-5920-2012; OI Bass, Steven/0000-0002-2089-9661 NR 67 TC 21 Z9 21 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 1 PY 1999 VL 60 IS 3 AR 034010 DI 10.1103/PhysRevD.60.034010 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300025 ER PT J AU Brodsky, SJ Pelaez, JR Toumbas, N AF Brodsky, SJ Pelaez, JR Toumbas, N TI Testing QCD with hypothetical tau leptons SO PHYSICAL REVIEW D LA English DT Article ID TOTAL CROSS-SECTION; INCLUSIVE MUON PRODUCTION; PION FORM-FACTOR; CM ENERGY-RANGE; SQUARE-ROOT-S; E+E ANNIHILATION; SUM-RULES; RENORMALIZATION-SCHEME; SPECTRAL FUNCTIONS; HADRON-PRODUCTION AB We construct new phenomenological tests of perturbative QCD by considering a hypothetical tau lepton of arbitrary mass which decays hadronically through the electromagnetic current. Its hadronic branching ratio can be computed directly as an integral over the e(+)e(-) annihilation cross section ratio, Re+e-. More generally, we can design a set of commensurate scale relations which test the applicability and self-consistency of leading twist QCD predictions by varying the weight function away from the form associated with the V-A decay of the physical tau. This method allows the wide range of Re+e- data (or other similar observables which define an effective charge) to be used as renormalization scheme and scale invariant probes of QCD. [S0556-2821(99)05713-6]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Pelaez, Jose/K-9767-2014 OI Pelaez, Jose/0000-0003-0737-4681 NR 45 TC 20 Z9 20 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 1 PY 1999 VL 60 IS 3 AR 037501 DI 10.1103/PhysRevD.60.037501 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300061 ER PT J AU Geiger, K AF Geiger, K TI Propagation of gluons from a nonperturbative evolution equation in axial gauges SO PHYSICAL REVIEW D LA English DT Article ID DYSON-SCHWINGER EQUATIONS; QUANTUM CHROMODYNAMICS; AVERAGE ACTION; ASYMPTOTIC FREEDOM; FLOW EQUATIONS; TIME EVOLUTION; LANDAU GAUGE; MESON MODEL; CONFINEMENT; QCD AB We derive a nonperturbative evolution equation for the gluon propagator in axial gauges based on the framework of Wetterich's formulation of the exact renormalization group. We obtain asymptotic solutions to this equation in the ultraviolet and infrared limits. [S0556-2821(99)06113-5]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Geiger, K (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 62 TC 7 Z9 7 U1 0 U2 1 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 1 PY 1999 VL 60 IS 3 AR 034012 DI 10.1103/PhysRevD.60.034012 PG 36 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300027 ER PT J AU Goity, JL Roberts, W AF Goity, JL Roberts, W TI Relativistic chiral quark model for pseudoscalar emission from heavy mesons SO PHYSICAL REVIEW D LA English DT Article ID CONSTITUENT QUARK; PERTURBATION-THEORY; STRONG DECAYS; HADRONS; SYMMETRY AB The amplitudes for one-pion mediated transitions between heavy meson excited states are obtained in the framework of the relativistic chiral quark model. The effective coupling constants to pions and the decay widths of excited heavy mesons with l less than or equal to 2 for non-radially excited, and the l = 0 radially excited mesons are presented for both charmed and b-flavored mesons. We also discuss the allowed decays of strange excited heavy mesons by emission of a K meson. [S05556-2821(99)05213-3]. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. RP Goity, JL (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. NR 26 TC 40 Z9 40 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 1 PY 1999 VL 60 IS 3 AR 034001 DI 10.1103/PhysRevD.60.034001 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300016 ER PT J AU Grinstein, B Lebed, RF AF Grinstein, B Lebed, RF TI B+-> D-s(*+)gamma and B+--> D*+gamma as probes of V-ub SO PHYSICAL REVIEW D LA English DT Article ID CHIRAL PERTURBATION-THEORY; HEAVY-QUARK SYMMETRY; SEMILEPTONIC B-DECAY; FORM-FACTORS; LEPTON SPECTRUM; HADRONS; MESONS; QCD AB The decays B+ --> D-s*(+) gamma and B+ --> D*(+) gamma can be used for an extraction of \V-ub\. When the b and c quarks are nearly degenerate, the rate for these modes can be determined in terms of other observed rates, namely B (B) over bar mixing and D* --> D gamma decay. To this end, we introduce a novel application of heavy quark and flavor symmetries. Although somewhat unrealistic, this limit provides us with a first estimate of these rates. [S0556-2821(99)50115-X]. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RI Grinstein, Benjamin/H-5777-2015 OI Grinstein, Benjamin/0000-0003-2447-4756 NR 23 TC 16 Z9 16 U1 0 U2 1 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 1 PY 1999 VL 60 IS 3 AR 031302 DI 10.1103/PhysRevD.60.031302 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300003 ER PT J AU Hall, LJ Weiner, N AF Hall, LJ Weiner, N TI U(2) and maximal mixing of nu(mu) SO PHYSICAL REVIEW D LA English DT Article ID FLAVOR SYMMETRY; ATMOSPHERIC NEUTRINOS; LSND EXPERIMENT; DARK-MATTER; SOLAR; OSCILLATIONS; PHYSICS; FERMION; LIGHT AB A U(2) flavor symmetry can successfully describe charged fermion masses and mixings, and suppress SUSY FCNC processes, making it a viable candidate for a theory of flavor. We show that a direct application of this U(2) flavor symmetry automatically predicts a mixing of 45 degrees for nu(mu) double right arrow nu(s), where nu(s) is a light, right-handed state. The introduction of an additional flavor symmetry acting on the right-handed neutrinos makes the model phenomenologically viable, explaining the solar neutrino deficit as well as the atmospheric neutrino anomaly, while giving a potential hot dark matter candidate and retaining the theory's predictivity in the quark sector. [S0556-2821(99)04509-9]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Hall, LJ (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 22 TC 14 Z9 14 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 1 PY 1999 VL 60 IS 3 AR 033005 DI 10.1103/PhysRevD.60.033005 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300012 ER PT J AU Ivanov, MA Kalinovsky, YL Roberts, CD AF Ivanov, MA Kalinovsky, YL Roberts, CD TI Survey of heavy-meson observables SO PHYSICAL REVIEW D LA English DT Article ID TRANSITION FORM-FACTORS; WEAK DECAYS; QUARK PROPAGATOR; CHARGE RADIUS; MODEL; QCD; CONFINEMENT; SYMMETRY; PHYSICS; APPROXIMATION AB We employ a Dyson-Schwinger equation model to effect a unified and uniformly accurate description of light- and heavy-meson observables, which we characterize by heavy-meson leptonic decays, semileptonic heavy-to-heavy and heavy-to-light transitions, B --> D*, D, rho, pi; D --> K*, K, pi, radiative and strong decays, B-(s)* --> B((s))gamma; D-(s)* --> D((s))gamma, D pi, and the rare B --> K*gamma flavor-changing neutral-current process. We elucidate the heavy-quark limit of these processes and, using a model-independent mass formula valid for all nonsinglet pseudoscalar mesons, demonstrate that their mass rises linearly with the mass of their heaviest constituent. In our numerical calculations we eschew a heavy-quark expansion and rely instead on the observation that the dressed c,b-quark mass functions are well approximated by a constant, interpreted as their constituent mass: we find (M) over cap(c) = 1.32 GeV and (M) over cap(b) = 4.65 GeV. The calculated heavy-meson leptonic decay constants and transition form factors are a necessary element in the experimental determination of CKM matrix elements. The results also show that this framework, as employed hitherto, is able to describe vector meson polarization observables well. [S0556-2821(99)08013-3]. C1 Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Russia. Joint Inst Nucl Res, Lab Comp Tech & Automat, Dubna 141980, Russia. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Ivanov, MA (reprint author), Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Russia. NR 54 TC 114 Z9 115 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 1 PY 1999 VL 60 IS 3 AR 034018 DI 10.1103/PhysRevD.60.034018 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300033 ER PT J AU Ligeti, Z Luke, M Manohar, AV Wise, RB AF Ligeti, Z Luke, M Manohar, AV Wise, RB TI The (B)over-bar -> X-s gamma photon spectrum SO PHYSICAL REVIEW D LA English DT Article ID LEPTON SPECTRUM; HEAVY-QUARK; PERTURBATION-THEORY; LEADING LOGARITHMS; QCD CORRECTIONS; POLE MASS; B-DECAYS; B->X(S)GAMMA; MOMENTS; SCATTERING AB The photon energy spectrum in inclusive weak radiative (B) over bar --> X(s)gamma decay is computed to order alpha(s)(2)beta(0). This result is used to extract a value for the heavy quark effective theory (HQET) parameter <(Lambda)over bar> from the average [1-2E(gamma)/m(B)], and a value of the parameter lambda(1) from [(1-2E(gamma)/m(B))(2)]. An accurate measurement of [1-2E(gamma)/m(B)] can determine the size of the nonperturbative contributions to the Y(1S) mass which cannot be absorbed into the b quark pole mass. [S0556-2821(99)00217-9]. C1 Fermilab Natl Accelerator Lab, Theory Grp, Batavia, IL 60510 USA. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. CALTECH, Pasadena, CA 91125 USA. RP Fermilab Natl Accelerator Lab, Theory Grp, POB 500, Batavia, IL 60510 USA. NR 40 TC 70 Z9 69 U1 0 U2 1 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 1 PY 1999 VL 60 IS 3 AR 034019 DI 10.1103/PhysRevD.60.034019 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300034 ER PT J AU Martin, SP Wells, JD AF Martin, SP Wells, JD TI Motivation and detectability of an invisibly decaying Higgs boson at the Fermilab Tevatron SO PHYSICAL REVIEW D LA English DT Article ID E(+)E(-) COLLISIONS; HADRON COLLIDERS; STANDARD MODEL; W+W PRODUCTION; CERN LHC; SEARCH; DIMENSIONS; SUPERSYMMETRY; MILLIMETER; COUPLINGS AB A Higgs boson with a mass below 150 GeV has a total decay width of less than 20 MeV into accessible standard model states. This narrow width means that the usual branching fractions for such a light Higgs boson are highly susceptible to any new particles to which it has unsuppressed couplings. In particular, there are many reasonable and interesting theoretical ideas that naturally imply an invisibly decaying Higgs boson. The motivations include models with light supersymmetric neutralinos, spontaneously broken lepton number, radiatively generated neutrino masses, additional singlet scalar(s), or right-handed neutrinos in the extra dimensions of TeV gravity. We discuss these approaches to model building and their implications for Higgs boson phenomenology in future Fermilab Tevatron runs. We find, for example, that the Tevatron with 30 fb(-1) integrated luminosity can make a 3 sigma observation in the l(+)l(-) + E-T channel for a 125 GeV Higgs bosom that is produced with the same strength as the standard model Higgs boson but always decays invisibly. We also analyze the b (b) over bar + E-T final state signal and conclude that it is not as sensitive, but it may assist in excluding the possibility of an invisibly decaying Higgs bosom or enable confirmation of an observed signal in the dilepton channel. We argue that a comprehensive Higgs boson search at the Tevatron should include the possibility that the Higgs boson decays invisibly. [S0556-2821(99)04815-8]. C1 No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. CERN, Div Theory, CH-1211 Geneva, Switzerland. RP Martin, SP (reprint author), No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. NR 44 TC 13 Z9 13 U1 1 U2 1 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 1 PY 1999 VL 60 IS 3 AR 035006 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 223HU UT WOS:000081836300055 ER PT J AU Lenosky, TJ Kress, JD Collins, LA Redmer, R Juranek, H AF Lenosky, TJ Kress, JD Collins, LA Redmer, R Juranek, H TI Simulations of fluid hydrogen: Comparison of a dissociation model with tight-binding molecular dynamics SO PHYSICAL REVIEW E LA English DT Article ID SHOCKED LIQUID DEUTERIUM; DENSE HYDROGEN; EQUATION; STATE; HOT; THERMODYNAMICS; TRANSITION; PLASMA; METALS; MBAR AB We compare the results of two complementary approaches, tight-binding molecular-dynamics simulations and a dissociation model, for determining the characteristics of dense, fluid hydrogen at pressures extending to megabars and temperatures to 10 000 K. Two tight-binding models were examined: one parametrization emphasized crystalline, molecular, and fluid properties, the other focused more on the intricate molecular interactions involving up to four hydrogen atoms. The two tight-binding cases and the dissociation model agree reasonably well for a variety of properties, including the equation of state, dissociation degree, and proton pair-correlation functions. In simulations of recently reported laser-driven shock experiments, the tight-binding and dissociative models predict different maximum compressions of four and five, respectively. We discuss the sensitivities of the models as well as give estimates for the region of validity of the chemical picture (dissociation model) and the accuracy of the dynamical picture (tight-binding simulations) in cases where molecular hydrogen still dominates the physical behavior. [S1063-651X(99)02608-2]. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Rostock, Fachbereich Phys, D-18051 Rostock, Germany. RP Lenosky, TJ (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Redmer, Ronald/F-3046-2013 NR 40 TC 15 Z9 15 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 EI 1550-2376 J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 1665 EP 1673 DI 10.1103/PhysRevE.60.1665 PN B PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100001 PM 11969948 ER PT J AU Kalyuzhnyi, YV Cui, ST Cummings, PT Cochran, HD AF Kalyuzhnyi, YV Cui, ST Cummings, PT Cochran, HD TI Distribution functions of a simple fluid under shear: Low shear rates SO PHYSICAL REVIEW E LA English DT Article ID DENSE SIMPLE FLUIDS; NONEQUILIBRIUM STRUCTURE; MODELS AB Anisotropic pair distribution functions for a simple, soft sphere fluid at moderate and high density under shear have been calculated by nonequilibrium molecular dynamics, by equilibrium molecular dynamics with a nonequilibrium potential, and by a nonequilibrium distribution function theory [H. H. Can and B. C. Eu, Phys. Rev. A 45, 3670 (1992)] and some variants. The nonequilibrium distribution function theory consists of a nonequilibrium Ornstein-Zernike relation, a closure relation, and a nonequilibrium potential and is solved in spherical harmonics. The distortion of the fluid structure due to shear is presented as the difference between the nonequilibrium and equilibrium pair distribution functions. From comparison of the results of theory against results of equilibrium molecular dynamics with the nonequilibrium potential at low shear rates, it is concluded that, for a given nonequilibrium potential, the theory is reasonably accurate, especially with the modified hypernetted chain closure. The equilibrium molecular-dynamics results with the nonequilibrium potential are also compared against the results of nonequilibrium molecular dynamics and suggest that the nonequilibrium potential used is not very accurate. In continuing work, a nonequilibrium potential better suited to high shear rates [H. H. Can and B. C. Eu, Phys. Rev. A 46, 6344 (1992)] is being tested. [S1063-651X(99)05608-1]. C1 Inst Condensed Matter Phys, UA-290011 Lviv, Ukraine. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RP Kalyuzhnyi, YV (reprint author), Inst Condensed Matter Phys, Svientsitskoho 1, UA-290011 Lviv, Ukraine. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 18 TC 6 Z9 7 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 1716 EP 1723 DI 10.1103/PhysRevE.60.1716 PN B PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100006 PM 11969953 ER PT J AU Ramshaw, JD AF Ramshaw, JD TI Simple model for linear and nonlinear mixing at unstable fluid interfaces in spherical geometry SO PHYSICAL REVIEW E LA English DT Article ID VARIABLE ACCELERATION; RAYLEIGH-TAYLOR AB A simple model was recently described for predicting linear and nonlinear mixing at an unstable planar fluid interface subjected to an arbitrary time-dependent variable acceleration history [J. D. Ramshaw, Phys. Rev. E 58, 5834 (1998)]. Here we present an analogous model for describing the mixing of two adjacent spherical fluid shells of different density resulting from an arbitrary time-dependent mean interface radius R(t). As in the planar case, the model is based on a heuristic expression for the kinetic energy of the system. This expression is based on that for the kinetic energy of a linearly perturbed interface, but with a dynamically renormalized effective wavelength which becomes proportional to the half-width a(t) of the mixing layer in the nonlinear regime. An equation of:motion for s=R(2)a is then derived from Lagrange's equations. This evolution equation properly reduces to Plesset's equation for small perturbations, and to the previous planar model in the limit of very large R. The conservation properties of the model are established, and a suitable numerical scheme which preserves these properties is proposed, [S1063-651X(99)13908-4]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Ramshaw, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 5 TC 5 Z9 5 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 1775 EP 1780 DI 10.1103/PhysRevE.60.1775 PN B PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100015 PM 11969962 ER PT J AU Aranson, IS Tsimring, LS Vinokur, VM AF Aranson, IS Tsimring, LS Vinokur, VM TI Continuum theory of axial segregation in a long rotating drum SO PHYSICAL REVIEW E LA English DT Article ID GRANULAR MEDIA; BINARY MIXTURE; MODEL; STRATIFICATION; PATTERNS; DYNAMICS; MIXER AB We develop a continuum description for the axial segregation of granular materials in a long rotating drum based on the dynamics of the thin near-surface granular flow coupled to bulk flow. The equations of motion are reduced to the one-dimensional system for two local variables only, the concentration difference and the dynamic angle of repose, or the average slope of the free surface. The parameters of the system are established from comparison with experimental data. The resulting system describes both initial transient traveling wave dynamics and the formation of quasi-stationary bands of segregated materials. A long-term evolution proceeds through slow logarithmic coarsening of the band structure which is analogous to the spinoidal decomposition described by the Cahn-Hilliard equation. [S1063-651X(99)08508-6]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif San Diego, Inst Nonlinear Sci, La Jolla, CA 92093 USA. RP Aranson, IS (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Aranson, Igor/I-4060-2013 NR 23 TC 43 Z9 43 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 1975 EP 1987 DI 10.1103/PhysRevE.60.1975 PN B PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100043 PM 11969990 ER PT J AU Shvets, G Fisch, NJ Pukhov, A Meyer-ter-Vehn, J AF Shvets, G Fisch, NJ Pukhov, A Meyer-ter-Vehn, J TI Generation of periodic accelerating structures in plasma by colliding laser pulses SO PHYSICAL REVIEW E LA English DT Article ID RAMAN-SCATTERING; ELECTRONS; WAVES AB A mechanism for generating large (>1 GeV/m)accelerating wakes in a plasma is proposed. Two slightly detuned counterpropagating laser beams, an ultrashort timing pulse and a long pump, exchange photons and deposit the recoil momentum in plasma electrons. This produces a localized region of electron current, which acts as a virtual electron beam, inducing intense plasma wakes with phase velocity equal to the group velocity of the short pulse. Modulating the pumping beam generates periodic accelerating structures in the plasma ("plasma linac") which can be used for particle acceleration unlimited by the dephasing between the particles and the wake. An important difference between this type of plasma accelerator and the conventional wakefield accelerators is that this type can be achieved with laser intensities I much less than 10(18) W/cm(2). [S1063-651X(99)15708-8]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Max Planck Inst Quantenopt, D-85748 Garching, Germany. RP Shvets, G (reprint author), Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RI pukhov, alexander/C-8082-2016 NR 18 TC 35 Z9 35 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 2218 EP 2223 DI 10.1103/PhysRevE.60.2218 PN B PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100069 PM 11970016 ER PT J AU Carlsten, BE AF Carlsten, BE TI Thermalization of an intense, space-charge-dominated electron beam in a long focusing channel SO PHYSICAL REVIEW E LA English DT Article ID EMITTANCE COMPENSATION; GROWTH AB A continuous electron beam with a correlated emittance will eventually thermalize. Initially, the beam emittance for an intense, high-brightness, space-charge-dominated beam will oscillate, but after a sufficiently long time, it will reach an equilibrium value. The emittance oscillations are due to coherent transverse plasma oscillations in the beam and are a manifestation of periodic energy exchange between potential and kinetic energies. The beam eventually attains an equilibrium emittance, as the beam equipartitions the kinetic and potential energies. This equipartioning is reached as the beam thermalizes due to a form of Landau damping of the radial oscillations at different radial positions within the beam. Slight differences in the transverse plasma oscillation frequency for different radial positions lead to incoherence in the oscillations. In this paper, we calculate the equilibrium time scales required for equipartioning. We show that the equilibrium emittance scalings and magnitude can be predicted by conservation of energy considerations. In addition, we show that, in the space-charge dominated regime,there is a correspondence between the energy-conservation approach and the kinematic approach. [S1063-651X(99)10608-1]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Carlsten, BE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 3 Z9 3 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP 2280 EP 2289 DI 10.1103/PhysRevE.60.2280 PN B PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CW UT WOS:000082235100076 PM 11970023 ER PT J AU Hamilton, WA Butler, PD Magid, LJ Han, Z Slawecki, TM AF Hamilton, WA Butler, PD Magid, LJ Han, Z Slawecki, TM TI Fast relaxation of a hexagonal Poiseuille shear-induced near-surface phase in a threadlike micellar solution SO PHYSICAL REVIEW E LA English DT Article ID ANGLE NEUTRON-SCATTERING; STRING PHASE; ALIGNMENT; FLOW AB The dynamics of near-surface conformations in complex fluids under flow should dramatically affect their rheological properties. We have made the first measurements resolving the decay kinetics of a hexagonal phase induced in a threadlike polyionic micellar system under Poiseuille shear near a quartz surface. Upon cessation of shearing flow, this minimum interference crystalline phase formed within similar to 20 mu m of the surface "melts" to a metastable two-dimensional liquid of aligned micelles in similar to 0.7 s. This is some three orders of magnitude shorter than the time required for bulk (Couette) shear-aligned micelles in this system to reach a fully entangled state. [S1063-651X(99)50808-8]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RP Hamilton, WA (reprint author), Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RI Butler, Paul/D-7368-2011 NR 13 TC 15 Z9 15 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD AUG PY 1999 VL 60 IS 2 BP R1146 EP R1149 DI 10.1103/PhysRevE.60.R1146 PN A PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 230CU UT WOS:000082234900010 PM 11969939 ER PT J AU Kadrmas, DJ DiBella, EVR Huesman, RH Gullberg, GT AF Kadrmas, DJ DiBella, EVR Huesman, RH Gullberg, GT TI Analytical propagation of errors in dynamic SPECT: estimators, degrading factors, bias and noise SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID CARDIAC SPECT; SCATTER COMPENSATION; INPUT FUNCTION; RECONSTRUCTION; TEBOROXIME; ACQUISITION; PARAMETERS; KINETICS; SYSTEM AB Dynamic SPECT is a relatively new technique that may potentially benefit many imaging applications. Though similar to dynamic PET, the accuracy and precision of dynamic SPECT parameter estimates are degraded by factors that differ from those encountered in PET. In this work we formulate a methodology for analytically studying the propagation of errors from dynamic projection data to kinetic parameter estimates. This methodology is used to study the relationships between reconstruction estimators, image degrading factors, bias and statistical noise for the application of dynamic cardiac imaging with Tc-99m-teburoxime. Dynamic data were simulated for a torso phantom, and the effects of attenuation, detector response and scatter were successively included to produce several data sets. The data were reconstructed to obtain both weighted and unweighted least squares solutions, and the kinetic rate parameters for a two-compartment model were estimated. The expected values and standard deviations describing the statistical distribution of parameters that would be estimated from noisy data were calculated analytically. The results of this analysis present several interesting implications for dynamic SPECT. Statistically weighted estimators performed only marginally better than unweighted ones, implying that more computationally efficient unweighted estimators may be appropriate. This also suggests that it may be beneficial to focus future research efforts upon regularization methods with beneficial bias-variance trade-offs. Other aspects of the study describe the fundamental limits of the bias-variance trade-off regarding physical degrading factors and their compensation. The results characterize the effects of attenuation, detector response and scatter, and they are intended to guide future research into dynamic SPECT reconstruction and compensation methods. C1 Univ Utah, CAMT, Dept Radiol, Med Imaging Res Lab, Salt Lake City, UT 84108 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. RP Kadrmas, DJ (reprint author), Univ Utah, CAMT, Dept Radiol, Med Imaging Res Lab, 729 Arapeen Dr, Salt Lake City, UT 84108 USA. OI DiBella, Edward/0000-0001-9196-3731 FU NHLBI NIH HHS [R01 HL50663, R01 HL050663, R01 HL050663-05] NR 27 TC 22 Z9 22 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0031-9155 J9 PHYS MED BIOL JI Phys. Med. Biol. PD AUG PY 1999 VL 44 IS 8 BP 1997 EP 2014 DI 10.1088/0031-9155/44/8/311 PG 18 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA 226QL UT WOS:000082031800011 PM 10473210 ER PT J AU Chen, SY AF Chen, SY TI Preface SO PHYSICS OF FLUIDS LA English DT Editorial Material C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Yale Univ, New Haven, CT 06520 USA. RP Chen, SY (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010 NR 0 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP IV EP IV PG 1 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500001 ER PT J AU Vorobieff, P Rivera, M Ecke, RE AF Vorobieff, P Rivera, M Ecke, RE TI Soap film flows: Statistics of two-dimensional turbulence SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB ID DECAYING TURBULENCE; PASSIVE SCALAR; VORTICITY; INTERMITTENCY; CASCADE AB Soap film flows provide a very convenient laboratory model for studies of two-dimensional (2-D) hydrodynamics including turbulence. For a gravity-driven soap film channel with a grid of equally spaced cylinders inserted in the flow, we have measured the simultaneous velocity and thickness fields in the irregular flow downstream from the cylinders. The velocity field is determined by a modified digital particle image velocimetry method and the thickness from the light scattered by the particles in the film. From these measurements, we compute the decay of mean energy, enstrophy, and thickness fluctuations with downstream distance, and the structure functions of velocity, vorticity, thickness fluctuation, and vorticity flux. From these quantities we determine the microscale Reynolds number of the flow R(lambda)approximate to 100 and the integral and dissipation scales of 2D turbulence. We also obtain quantitative measures of the degree to which our flow can be considered incompressible and isotropic as a function of downstream distance. We find coarsening of characteristic spatial scales, qualitative correspondence of the decay of energy and enstrophy with the Batchelor model, scaling of energy in k space consistent with the k(-3) spectrum of the Kraichnan-Batchelor enstrophy-scaling picture, and power-law scalings of the structure functions of velocity, vorticity, vorticity flux, and thickness. These results are compared with models of 2-D turbulence and with numerical simulations. (C) 1999 American Institute of Physics. [S1070-6631(99)03108-6]. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Condesed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. Univ Pittsburgh, Pittsburgh, PA USA. RP Vorobieff, P (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RI Vorobieff, Peter/B-3376-2011; OI Vorobieff, Peter/0000-0003-0631-7263; Ecke, Robert/0000-0001-7772-5876 NR 32 TC 46 Z9 46 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2167 EP 2177 DI 10.1063/1.870078 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500022 ER PT J AU Cao, NZ Chen, SY Doolen, GD AF Cao, NZ Chen, SY Doolen, GD TI Statistics and structures of pressure in isotropic turbulence SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB ID NAVIER-STOKES TURBULENCE; FULLY-DEVELOPED TURBULENCE; HOMOGENEOUS TURBULENCE; INTENSE VORTICITY; FLUCTUATIONS; INTERMITTENCY; DISSIPATION; FLOWS AB Statistics and structures of pressure in three-dimensional incompressible isotropic turbulence are studied using high-resolution direct numerical simulation for Taylor microscale Reynolds numbers up to 220. It is found that the probability distribution function (PDF) of pressure has negative skewness due to both kinematic and dynamic effects, in contrast to the statistics of the pressure head, whose PDF is almost symmetric. The statistical relations among pressure, vorticity, dissipation and kinetic energy are investigated using conditional averaging. The averaged pressure, conditional on the local enstrophy, shows a linear dependence on enstrophy in the high-enstrophy region. Structure relations between pressure and other physical quantities are qualitatively examined using three-dimensional visualization of iso-surfaces. It is found that the high-vorticity regions are strongly correlated with the low-pressure regions. However, it appears that experimental visualization techniques for detecting high-intensity vortices using microbubbles in low-pressure regions might only be valid for those very-high-vorticity regions where the local enstrophy is at least five times higher than the root mean square enstrophy. The scaling law of the pressure structure function is also presented for both conventional and extended self-similarity. It is found that the pressure increment, delta(r)p, scales with the velocity increment, delta(r)u, for the Reynolds numbers studied: delta(r)p similar to delta(r)u. For flows at moderate Reynolds numbers, it is demonstrated that the extended self-similarity gives better pressure scalings than results from traditional similarity solutions. (C) 1999 American Institute of Physics. [S1070-6631(99)00108-7]. C1 IBM Corp, Div Res, TJ Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Cao, NZ (reprint author), IBM Corp, Div Res, TJ Watson Res Ctr, POB 218, Yorktown Heights, NY 10598 USA. RI Chen, Shiyi/A-3234-2010 NR 37 TC 46 Z9 46 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2235 EP 2250 DI 10.1063/1.870085 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500029 ER PT J AU Chen, S Foias, C Holm, DD Olson, E Titi, ES Wynne, S AF Chen, S Foias, C Holm, DD Olson, E Titi, ES Wynne, S TI A connection between the Camassa-Holm equations and turbulent flows in channels and pipes SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB ID LOW-REYNOLDS-NUMBER; STRESS; FLUIDS; MODELS AB In this paper we discuss recent progress in using the Camassa-Holm equations to model turbulent flows. The Camassa-Holm equations, given their special geometric and physical properties, appear particularly well suited for studying turbulent flows. We identify the steady solution of the Camassa-Holm equation with the mean flow of the Reynolds equation and compare the results with empirical data for turbulent flows in channels and pipes. The data suggest that the constant alpha version of the Camassa-Holm equations, derived under the assumptions that the fluctuation statistics are isotropic and homogeneous, holds to order alpha distance from the boundaries. Near a boundary, these assumptions are no longer valid and the length scale alpha is seen to depend on the distance to the nearest wall. Thus, a turbulent flow is divided into two regions: the constant alpha region away from boundaries, and the near wall region. In the near wall region, Reynolds number scaling conditions imply that alpha decreases as Reynolds number increases. Away from boundaries, these scaling conditions imply alpha is independent of Reynolds number. Given the agreement with empirical and numerical data, our current work indicates that the Camassa-Holm equations provide a promising theoretical framework from which to understand some turbulent flows. (C) 1999 American Institute of Physics. [S1070-6631(99)00508-5]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Indiana Univ, Dept Math, Bloomington, IN 47405 USA. Univ Calif Irvine, Dept Math, Irvine, CA 92697 USA. Univ Calif Irvine, Dept Mech Engn, Irvine, CA 92697 USA. Univ Calif Irvine, Dept Aerosp Engn, Irvine, CA 92697 USA. Univ Calif Los Alamos Natl Lab, Inst Geophys & Planetary Phys, Los Alamos, NM 87545 USA. RP Chen, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010; OI Holm, Darryl D/0000-0001-6362-9912 NR 35 TC 147 Z9 150 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2343 EP 2353 DI 10.1063/1.870096 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500041 ER PT J AU Turner, L AF Turner, L TI Macroscopic structures of inhomogeneous, Navier-Stokes turbulence SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB AB Macroscopic properties of inhomogeneous, Navier-Stokes turbulence are calculated using a fundamental theoretical approach. Starting from a set of solenoidal basis vectors suitable for describing a turbulence bounded by infinite, parallel free-slip planes, invoking a random-phase approximation, and using the eddy-damped quasinormal Markovian closure, various quantities of dynamical interest are calculated. Quantities that affect the evolution of both the momentum density and the kinetic energy density of the turbulently evolving fluid are studied. These quantities include the ensemble-averaged values of gradients of the triple-velocity correlation and the pressure-velocity correlation. When the energy spectrum in wave-number space lacks certain reflection symmetries, a nontrivial mean flow velocity will be seen to emerge out of the turbulent eddies. In turn, these mean flow velocities will affect the evolution of the turbulence. Of course, such physically interesting mean-field structures cannot arise in dynamics suffused by the assumption of statistical homogeneity. (C) 1999 American Institute of Physics. [S1070-6631(99)02108-X]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Turner, L (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 7 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2367 EP 2380 DI 10.1063/1.870098 PG 14 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500043 ER PT J AU Romero, CA Harlow, FH Rauenzahn, RM AF Romero, CA Harlow, FH Rauenzahn, RM TI Crenulative turbulence in a converging nonhomogeneous material SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB AB Crenulative turbulence is a nonlinear extension of the Bell-Plesset instability, usually observed in a converging system in which there is a nonhomogeneous response of stress to strain and/or strain rate. In general, crenulation occurs in any circumstance in which the mean flow streamlines converge the material more strongly than the compressibility can accommodate. Elements of the material slip past each ether, resulting in local fluctuations in velocity from that of the mean flow, producing a type of turbulence that is more kinematic than inertial. For a homogeneous material, crenulation occurs at the atomic or molecular scale. With nonhomogeneous stress response at larger scales, the crenulative process can also occur at those larger scales. The results are manifested by a decrease in the rate of dissipation to heat, and by the configurationally irreversible mixing of nonhomogeneities across any mean-flow-transported interface. A mathematical description of the crenulative process is obtained by means of Reynolds decomposition of the appropriate variables, and the derivation of transport equations for the second-order moments that arise in the mean-flow momentum and energy equations. The theory is illustrated by application to the spherical convergence of an incompressible fluid with nonhomogeneous distribution of kinematic viscosity. (C) 1999 American Institute of Physics. [S1070-6631(99)01208-8]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. RP Romero, CA (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2411 EP 2424 DI 10.1063/1.870102 PG 14 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500047 ER PT J AU Wilson, P Andrews, M Harlow, F AF Wilson, P Andrews, M Harlow, F TI Spectral nonequilibrium in a turbulent mixing layer SO PHYSICS OF FLUIDS LA English DT Article; Proceedings Paper CT International Conference on Turbulence CY MAR, 1998 CL LOS ALAMOS NATL LAB, LOS ALAMOS, NEW MEXICO HO LOS ALAMOS NATL LAB ID RAYLEIGH-TAYLOR; TRANSPORT AB The stochastically steady buoyancy-driven turbulent mix of unstably thermally stratified hot and cold water in a channel is examined by means of thermocouples placed at various stations downstream from an entrance splitter plate. Two-time correlations of temperature fluctuations are converted to the approximate two-point correlations of density fluctuations that would occur in a time-evolving mixing layer. The spectral structure exhibits strong nonequilibrium near the splitter plate. Further downstream the spectral structure evolves to self-similarity. Evolution of the structural features is compared with the predictions of a turbulence spectral transport theory for the nonequilibrium behavior of a time-evolving mixing layer between two fluids of different density. Results of the comparison give tentative validation to most aspects of the theoretical description and suggest closure alterations for further enhancement of the transport-equation validity. (C) 1999 American Institute of Physics. [S1070-6631(99)01308-2]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. RP Wilson, P (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 27 TC 10 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1999 VL 11 IS 8 BP 2425 EP 2433 DI 10.1063/1.870103 PG 9 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 217ZH UT WOS:000081528500048 ER PT J AU Callen, JD Hegna, CC Rice, BW Strait, EJ Turnbull, AD AF Callen, JD Hegna, CC Rice, BW Strait, EJ Turnbull, AD TI Growth of ideal magnetohydrodynamic modes driven slowly through their instability threshold: Application to disruption precursors SO PHYSICS OF PLASMAS LA English DT Article ID FUSION TEST REACTOR; DIII-D DISCHARGES; TOKAMAK PLASMAS; INTERCHANGE MODES; SAWTOOTH COLLAPSE; MAGNETIC SHEAR; STABILITY; TRANSPORT; JET AB The growth of an ideal magnetohydrodynamic (MHD) instability in a high-temperature plasma is calculated in the case where the plasma beta is driven slowly through its instability threshold. The MHD perturbation grows faster than exponentially, approximately as exp[(t/tau)(3/2)]. Its characteristic growth time tau similar to(3/2)(2/3)<(gamma)over cap>(-2/3)(MHD)gamma(h)(-1/3) is a hybrid of the ideal MHD incremental growth rate <(gamma)over cap>(MHD) and the heating rate gamma(h). This simple model agrees well with the observed growth of disruption precursors in high beta DIII-D [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] discharges having strongly peaked pressure profiles, where the observed growth times of greater than or equal to 10(-4) s are significantly slower than the typical ideal MHD time scale of less than or equal to 10(-5) s. (C) 1999 American Institute of Physics. [S1070-664X(99)01508-6]. C1 Univ Wisconsin, Madison, WI 53706 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Gen Atom Co, San Diego, CA 92186 USA. RP Callen, JD (reprint author), Univ Wisconsin, Madison, WI 53706 USA. NR 28 TC 38 Z9 38 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 2963 EP 2967 DI 10.1063/1.873583 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100001 ER PT J AU Isaev, MY Mikhailov, MI Monticello, DA Mynick, HE Subbotin, AA Ku, LP Reiman, AH AF Isaev, MY Mikhailov, MI Monticello, DA Mynick, HE Subbotin, AA Ku, LP Reiman, AH TI The pseudo-symmetric optimization of the National Compact Stellarator Experiment SO PHYSICS OF PLASMAS LA English DT Article ID TRANSPORT; TOKAMAK AB A new experiment, the National Compact Stellarator Experiment (NCSX) [Monticello "Physics Consideration for the Design of NCSX," Proceedings of 25th EPS Conference on Controlled Fusion and Plasma Physics, Prague, 1998 (European Physical Society, Petit-Lancy), paper 1.187], hopes to overcome the deleterious ripple transport usually associated with stellarators by creating a quasi-axisymmetric configuration. A quasi-axisymmetric configuration is one in which the Fourier spectrum of the magnetic field strength in so-called Boozer coordinates is dominated by the toroidal angle averaged (n=0) components. In this article the concept of pseudosymmetry is used to improve ripple transport in a four-period variant of NCSX. By definition, pseudosymmetric magnetic configurations have no locally trapped particles. To obtain a pseudosymmetric configuration, different target functions are considered. It is found that a target function equal to the area of ripple of the magnetic field magnitude along the field line is very effective in reducing the neoclassical transport coefficient. (C) 1999 American Institute of Physics. [S1070-664X(99)01108-8]. C1 IV Kurchatov Atom Energy Inst, Russian Res Ctr, Nucl Fus Inst, Moscow 123182, Russia. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Isaev, MY (reprint author), IV Kurchatov Atom Energy Inst, Russian Res Ctr, Nucl Fus Inst, Moscow 123182, Russia. RI Isaev, Maxim/A-7910-2012 OI Isaev, Maxim/0000-0002-8492-0650 NR 16 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 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 3174 EP 3179 DI 10.1063/1.873557 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100024 ER PT J AU Ruskov, E Bell, M Budny, RV McCune, DC Medley, SS Nazikian, R Synakowski, EJ von Goeler, S White, RB Zweben, SJ AF Ruskov, E Bell, M Budny, RV McCune, DC Medley, SS Nazikian, R Synakowski, EJ von Goeler, S White, RB Zweben, SJ TI Fusion performance analysis of plasmas with reversed magnetic shear in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID MULTICHANNEL NEUTRON COLLIMATOR; DEUTERIUM-TRITIUM EXPERIMENTS; TOROIDAL ALFVEN EIGENMODES; PELLET CHARGE-EXCHANGE; BEAM FUELING PROFILE; ENHANCED CONFINEMENT; ALPHA-PARTICLES; FAST IONS; TFTR; DISCHARGES AB A case for substantial loss of fast ions degrading the performance of tokamak fusion test reactor plasmas [Phys. Plasmas 2, 2176 (1995)] with reversed magnetic shear (RS) is presented. The principal evidence is obtained from an experiment with short (40-70 ms) tritium beam pulses injected into deuterium beam heated RS plasmas [Phys. Rev. Lett. 82, 924 (1999)]. Modeling of this experiment indicates that up to 40% beam power is lost on a time scale much shorter than the beam-ion slowing down time. Critical parameters which connect modeling and experiment are: The total 14 MeV neutron emission, its radial profile, and the transverse stored energy. The fusion performance of some plasmas with internal transport barriers is further deteriorated by impurity accumulation in the plasma core. (C) 1999 American Institute of Physics. [S1070-664X(99)04107-5]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Ruskov, E (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 51 TC 0 Z9 0 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 3247 EP 3262 DI 10.1063/1.873565 PG 16 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100033 ER PT J AU Hammer, JH Ryutov, DD AF Hammer, JH Ryutov, DD TI Linear stability of an accelerated, current carrying wire array SO PHYSICS OF PLASMAS LA English DT Article ID Z-PINCH EXPERIMENTS; PLASMAS; POWER AB The linear stability of an array of a large number of thin wires is considered. The wires form a cylindrical surface, accelerated toward the axis under the action of a current. Stability equations are derived and a complete classification of the modes is presented. In agreement with Felber and Rostoker [Phys. Fluids 24, 1049 (1981)], it is shown that there exist two types of modes: medial modes, with deformation in the rz plane, and lateral modes, with only azimuthal deformation. For a given axial wave number, k, the most unstable medial mode has all the wires moving in phase similar to an axisymmetric mode for a continuous shell, whereas the most unstable lateral perturbation has opposite displacements of neighboring wires. Lateral modes are of particular interest because they may remain unstable for parameters where medial modes are stable. Numerical analysis of the dispersion relation for a broad range of modes is presented. Some limiting cases are discussed. It is shown that k(1/2) scaling holds until surprisingly high wave numbers, even exceeding the inverse interwire distance. In the long-wavelength limit, the wires behave as a continuous shell with strong anisotropy of the electrical conductivity, i.e., high along the wires and vanishing across the wires. The results differ considerably from the modes of a thin, perfectly conducting shell. In particular, a new "zonal flow" mode is identified. [S1070-664X(99)01708-5]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Hammer, JH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 26 TC 17 Z9 17 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 3302 EP 3315 DI 10.1063/1.873598 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100039 ER PT J AU Goldman, SR Caldwell, SE Wilke, MD Wilson, DC Barnes, CW Hsing, WW Delamater, ND Schappert, GT Grove, JW Lindman, EL Wallace, JM Weaver, RP Dunne, AM Edwards, MJ Graham, P Thomas, BR AF Goldman, SR Caldwell, SE Wilke, MD Wilson, DC Barnes, CW Hsing, WW Delamater, ND Schappert, GT Grove, JW Lindman, EL Wallace, JM Weaver, RP Dunne, AM Edwards, MJ Graham, P Thomas, BR TI Shock structuring due to fabrication joints in targets SO PHYSICS OF PLASMAS LA English DT Article ID LASER; IGNITION; CAMERAS AB The use of copper-doped beryllium ablators on National Ignition Facility [J. A. Paisner , Laser Focus World 30, 75 (1994)] targets, in place of plastic, can require the bonding together of hemispheres with a joint of differing composition. Indirect drive experiments have been conducted on the Nova laser [J. L. Emmet, W. F. Krupke, and J. B. Trenholme, Sov. J. Quantum Electron. 13, 1 (1983)], and the resulting shock structuring compared with code simulations. It is concluded that one of the available codes, the RAGE code [R. M. Baltrusaitis , Phys. Fluids 8, 2471 (1996)] provides useful insight into the effect of joints. This code is then employed to obtain a physical picture of the shock front nonuniformity in terms of a secondary rarefaction and an oblique shock interacting with the main shock that propagates in the absence of the joint. A simple analysis reinforces this picture.(C) 1999 American Institute of Physics. [S1070-664X(99)03008-6]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Atom Weap Estab, Reading RG7 4PR, Berks, England. RP Goldman, SR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Dunne, Mike/B-4318-2014 OI Dunne, Mike/0000-0001-8740-3870 NR 25 TC 37 Z9 37 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 3327 EP 3336 DI 10.1063/1.873572 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100041 ER PT J AU Vesey, RA Pointon, TD Cuneo, ME Mehlhorn, TA Bailey, JE Johnson, DJ Stygar, WA AF Vesey, RA Pointon, TD Cuneo, ME Mehlhorn, TA Bailey, JE Johnson, DJ Stygar, WA TI Electron-anode interactions in particle-in-cell simulations of applied-B ion diodes SO PHYSICS OF PLASMAS LA English DT Article ID IMPLICIT PLASMA SIMULATION; SURFACE-FLASHOVER; DIVERGENCE; IMPEDANCE; TRANSPORT; FUSION; FLUID; TEMPERATURE; DESORPTION; GENERATION AB Particle-in-cell simulations of applied-B ion diodes using the QUICKSILVER code [D. B. Seidel , in Proceedings of the Europhysics Conference on Computational Physics, Amsterdam, 1990, edited by A. Tenner (World Scientific, Singapore, 1991), p. 475] have been augmented with Monte Carlo calculations of electron-anode interactions (reflection and energy deposition). Extraction diode simulations demonstrate a link between the instability evolution and increased electron loss and anode heating. Simulations of radial and extraction ion diodes show spatial nonuniformity in the predicted electron loss profile leading to hot spots on the anode that rapidly exceed the 350 degrees C-450 degrees C range, known to be sufficient for plasma formation on electron-bombarded surfaces. Thermal desorption calculations indicate complete desorption of contaminants with 15-20 kcal/mole binding energies in high-dose regions of the anode during the power pulse. Comparisons of parasitic ion emission simulations and experiment show agreement in some aspects, but also highlight the need for better ion source, plasma, and neutral gas models. (C) 1999 American Institute of Physics. [S1070-664X(99)01408-1]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Vesey, RA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 51 TC 10 Z9 10 U1 2 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 1999 VL 6 IS 8 BP 3369 EP 3387 DI 10.1063/1.873576 PG 19 WC Physics, Fluids & Plasmas SC Physics GA 219BC UT WOS:000081587100045 ER PT J AU Ghiorso, A AF Ghiorso, A TI Glenn Theodore Seaborg - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ghiorso, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD AUG PY 1999 VL 52 IS 8 BP 77 EP 78 DI 10.1063/1.882793 PN 1 PG 2 WC Physics, Multidisciplinary SC Physics GA 222HT UT WOS:000081779400020 ER PT J AU Hymus, GJ Ellsworth, DS Baker, NR Long, SP AF Hymus, GJ Ellsworth, DS Baker, NR Long, SP TI Does free-air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different seasons? A chlorophyll fluorescence study of mature loblolly pine SO PLANT PHYSIOLOGY LA English DT Article ID LONG-TERM EXPOSURE; PHOTOSYNTHETIC ELECTRON-TRANSPORT; PHOTOSYSTEM-II ACTIVITY; RISING ATMOSPHERIC CO2; ELEVATED CO2; ANTIOXIDATIVE ENZYMES; NET PHOTOSYNTHESIS; QUANTUM YIELD; LEAVES; ASSIMILATION AB Previous studies of the effects of growth at elevated CO2 on energy partitioning in the photosynthetic apparatus have produced conflicting results. The hypothesis was developed and tested that elevated CO2 increases photochemical energy use when there is a high demand for assimilates and decreases usage when demand is low. Modulated chlorophyll a fluorescence and leaf gas exchange were measured on needles at the top of a mature, 12-m loblolly pine (Pinus taeda L.) forest. Trees were exposed to ambient CO2 or ambient plus 20 Pa CO2 using free-air CO2 enrichment. During April and August, periods of shoot growth, light-saturated photosynthesis and linear electron transport were increased by elevated CO2. In November, when growth had ceased but temperatures were still moderate, CO2 treatment had no significant effect on linear electron transport. In February, when low temperatures were likely to inhibit translocation, CO2 treatment caused a significant decrease in linear electron transport. This coincided with a slower recovery of the maximum photosystem II efficiency on transfer of needles to the shade, indicating that growth in elevated CO2 induced a more persistent photoinhibition. Both the summer increase and the winter decrease in linear electron transport in elevated CO2 resulted from a change in photochemical quenching, not in the efficiency of energy transfer within the photosystem II antenna. There was no evidence of any effect of CO2 on photochemical energy sinks other than carbon metabolism. Our results suggest that elevated CO2 may increase the effects of winter stress on evergreen foliage. C1 Univ Essex, John Tabor Labs, Dept Biol Sci, Colchester CO4 3SQ, Essex, England. Brookhaven Natl Lab, Environm Biol & Instrumentat Div, Upton, NY 11973 USA. Univ Illinois, Dept Crop Sci, Edward R Madigan Lab 190, Urbana, IL 61801 USA. Univ Illinois, Dept Plant Biol, Edward R Madigan Lab 190, Urbana, IL 61801 USA. RP Long, SP (reprint author), Univ Essex, John Tabor Labs, Dept Biol Sci, Wivenhoe Pk, Colchester CO4 3SQ, Essex, England. RI Long, Stephen/A-2488-2008; OI Long, Stephen/0000-0002-8501-7164; Ellsworth, David/0000-0002-9699-2272 NR 40 TC 67 Z9 71 U1 0 U2 10 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD AUG PY 1999 VL 120 IS 4 BP 1183 EP 1191 DI 10.1104/pp.120.4.1183 PG 9 WC Plant Sciences SC Plant Sciences GA 227JZ UT WOS:000082078400027 ER PT J AU Zerbini, M Austin, M Bernabei, S Giruzzi, G Murakami, M Lohr, J Luce, TC Petty, CC Ponce, D Prater, R AF Zerbini, M Austin, M Bernabei, S Giruzzi, G Murakami, M Lohr, J Luce, TC Petty, CC Ponce, D Prater, R TI Correlation analysis of 110 GHz ECH modulation experiments on the DIII-D tokamak SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID CURRENT DRIVE; PLASMAS; TRANSPORT AB Experiments on electron cyclotron heating (ECH) power modulation have been carried out on the DIII-D tokamak with a gyrotron generating about 900 kW and operating at the second cyclotron harmonic, to investigate the power deposition in the plasma, to characterize the microwave beam and to study electron thermal transport. To this end the 110 GHz Gycom Centaur gyrotron output has been modulated in the range 50-300 Hz. The ECH power deposition, beam propagation and the plasma thermal diffusivity have been investigated by using the cross-correlation between the incident ECH power and the electron temperature reaction. C1 ENEA Fus, EURATOM Assoc, I-00044 Frascati, Roma, Italy. Univ Texas, Austin, TX 78712 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. CEA Cadarache, CEA Fus, EURATOM Assoc, St Paul Durance, France. Oak Ridge Natl Lab, Oak Ridge, TN USA. Gen Atom, San Diego, CA USA. RP Zerbini, M (reprint author), ENEA Fus, EURATOM Assoc, CP 65, I-00044 Frascati, Roma, Italy. NR 13 TC 7 Z9 7 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD AUG PY 1999 VL 41 IS 8 BP 931 EP 940 DI 10.1088/0741-3335/41/8/301 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 234LL UT WOS:000082486100001 ER PT J AU Keidar, M Beilis, II AF Keidar, M Beilis, II TI Hydrodynamic model of vacuum are plasma flow in a positively biased toroidal macroparticle filter SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID CURVED MAGNETIC FILTERS; ARC DEPOSITION SYSTEM; CATHODIC ARC; THIN-FILMS; TRANSPORT; DUCT; FIELD; EXPANSION; STRAIGHT; JET AB A hydrodynamic model of vacuum are plasma flow through a toroidal magnetized macroparticle duct has been developed. The case of the duct wall having positive potential with respect to the adjacent plasma is analysed. The quasi-neutral plasma and the sheath appearing near the duct wall were considered. The plasma parameters obtained in the sheath region were used as a boundary condition for the problem of the plasma flow. The plasma flow in the quasi-neutral region was modelled by sourceless steady-state equations. It was found that the plasma density distribution within the filter cross-section has a maximum near the outer wall. In the course of the flow through the duct the plasma velocity generally decreases along the duct and at the filter exit is about half of the initial value in the centre. We find that the plasma loss is mainly in the second half of the filter. The ion throughput at the exit cross-section depends upon the applied voltage drop and increases by a factor of two for the case of a magnetic field of about 0.01 T The ion throughput has a maximum at a duct bias of about 20 V. These results are in agreement with experiments. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tel Aviv Univ, Elect Discharge & Plasma Lab, IL-69978 Tel Aviv, Israel. RP Keidar, M (reprint author), Cornell Univ, Ithaca, NY 14853 USA. NR 32 TC 16 Z9 16 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD AUG PY 1999 VL 8 IS 3 BP 376 EP 383 DI 10.1088/0963-0252/8/3/306 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 231QC UT WOS:000082320500008 ER PT J AU Ding, WX Pinnaduwage, LA Tav, C McCorkle, DL AF Ding, WX Pinnaduwage, LA Tav, C McCorkle, DL TI The role of high Rydberg states in enhanced O- formation in a pulsed O-2 discharge SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID ELECTRON-ATTACHMENT; NEGATIVE-ION; LASER PHOTODETACHMENT; AMORPHOUS-SILICON; EXCITED MOLECULES; RF DISCHARGES; PLASMA; DENSITY; OXYGEN; SILANE AB Formation of O- ions in a pulsed discharge of O-2 was investigated in a Langmuir-probe-assisted photodetachment experiment. A large enhancement of negative ion formation was observed in the afterglow. Experimental results are consistent with O- formation via electron attachment to high Rydberg states of O-2 that survive into the afterglow. Such excited states can be produced by high-energy electron impact during the discharge. The lifetime of high-Rydberg molecules is estimated to be longer than 10 microseconds. The efficient production of O- ion by electron attachment to high-Rydberg O-2 molecules was further confirmed in a laser excitation experiment. The O- ions and O atoms produced via enhanced dissociative electron attachment to excited states of O-2 may be important for the chemical processes that occur in pulsed plasma remediation of contaminated air. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Pinnaduwage, LA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 46 TC 9 Z9 9 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD AUG PY 1999 VL 8 IS 3 BP 384 EP 391 DI 10.1088/0963-0252/8/3/307 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 231QC UT WOS:000082320500009 ER PT J AU Bilek, MMM Anders, A AF Bilek, MMM Anders, A TI Designing advanced filters for macroparticle removal from cathodic arc plasmas SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID VACUUM ARCS; TRANSPORT AB Curved magnetic filters are commonly used with cathodic arcs to remove macroparticles from the plasma stream, making them suitable for the preparation of smooth, dense and defect-free films. Plasma losses associated with these Biters are rather high. The highest reported ion current transported through a curved macroparticle filter is 2.5% of the are current. In this paper we show that it is possible to finely control both the shape and spatial position of the plasma beam as it passes through a curved magnetic filter by the addition of strategically placed current-carrying wires. Our modifications consisted of additional current loops at the entrance and exit of the filter to reduce the divergence of magnetic field lines there; a number of conducting wires were also placed outside the filter along its length to centre the beam in the filter. We were able to improve the plasma transport efficiency by modifying the paths of magnetic field lines through the 90 degrees filter with the aid of computer calculation, achieving a filtered titanium ion current up to 6.3% of the are current. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Bilek, MMM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 53,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 16 TC 26 Z9 26 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD AUG PY 1999 VL 8 IS 3 BP 488 EP 493 DI 10.1088/0963-0252/8/3/319 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 231QC UT WOS:000082320500021 ER PT J AU Cheng, JL Chen, W Pardey, R Cheng, SZD Wunderlich, B AF Cheng, JL Chen, W Pardey, R Cheng, SZD Wunderlich, B TI A solid-state C-13-NMR study of the mesophases of PEIM-9 (poly(4,4 '-phthaloimidobenzoylnonamethylene- oxycarbonyl)) SO POLYMERS FOR ADVANCED TECHNOLOGIES LA English DT Article DE PEIM-9; transconformations; annealing; crystallization ID POLY(ESTER IMIDE)S; NMR; CIS-1,4-POLYBUTADIENE; P,P'-BIBENZOATE); CRYSTALLIZATION; TRANSITIONS; POLYIMIDES; POLYMERS; SPACERS; PACKING AB On cooling from the melt, poly(4,4'-phthaloimidobenzoylnonamethyleneoxycarbonyl) (PEIM-9) forms a monotropic, smectic liquid crystal phase (T-i = 369.2 K). The main driving force for this mesophase formation is the attainment of nanophase separation of the mobile nonamethylene spacer from the geometrically rigid but irregular, phthaloimidobenzoyl group, coupled with partial conformational ordering of the CH2 groups (about 20% of the CH2 groups attain trans-conformations). It is shown by nuclear magnetic resonance that PEIM-9 consists at room temperature of two motionally distinguishable components. One is the liquid crystal that remains mobile to its glass transition temperature (T-g approximate to 323 K), the other a more rigid crystal with a large degree of conformational disorder. In this crystal phase (T-m approximate to 415 K) the conformationally disordered nonamethylene spacer has a similar amount of disorder than in the liquid crystal phase and the phthaloimidobenzoyl group is also not fully ordered. Even after long-term annealing, all molecules remain conformationally disordered but T-m increases to about approximate to 437 K. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Chromalox Div Emerson Elect, Murfreesboro, TN 37129 USA. Univ Akron, Maurice Morton Inst Polymer Sci, Akron, OH 44325 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 27 TC 5 Z9 5 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1042-7147 J9 POLYM ADVAN TECHNOL JI Polym. Adv. Technol. PD AUG PY 1999 VL 10 IS 8 BP 501 EP 512 PG 12 WC Polymer Science SC Polymer Science GA 231HR UT WOS:000082302900004 ER PT J AU Thanos, CD Bowie, JU AF Thanos, CD Bowie, JU TI p53 Family members p63 and p73 are SAM domain-containing proteins SO PROTEIN SCIENCE LA English DT Article DE Sterile Alpha Motif; tumor suppressor ID TYROSINE KINASES; RECEPTOR; ONCOPROTEIN; GENE AB Homologs of the tumor suppressor p53, called p63 and p73, have been identified. The p63 and p73 family members possess a domain structure similar to p53, but contain variable C-terminal extensions. We find that some of the C-terminal extensions contain Sterile Alpha Motif (SAM) domains. SAM domains are protein modules that an involved in protein-protein interactions. Consistent with this role, the C-terminal SAM domains of the p63 and p73 may regulate function by recruiting other protein effecters. C1 Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RP Bowie, JU (reprint author), Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. NR 21 TC 105 Z9 110 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD AUG PY 1999 VL 8 IS 8 BP 1708 EP 1710 PG 3 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 224PT UT WOS:000081908000015 PM 10452616 ER PT J AU Garcia, AE Hummer, G AF Garcia, AE Hummer, G TI Conformational dynamics of cytochrome c: Correlation to hydrogen exchange SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE nonlinear dynamics; molecular dynamics; protein hydration; hydration dynamics; strange dynamics ID NATIVE-PROTEIN DYNAMICS; ELECTRON-TRANSFER; MOLECULAR-DYNAMICS; FERRICYTOCHROME-C; FERROCYTOCHROME-C; FAST EVENTS; SIMULATIONS; ENERGY; HYDRATION; PATHWAY AB We study the dynamical fluctuations of horse heart cytochrome c by molecular dynamics (MD) simulations in aqueous solution, at four temperatures: 300 K, 360 K, 430 K, and 550 K. Each simulation covers a production time of at least 1.5 nanoseconds (ns). The conformational dynamics of the system is analyzed in terms of collective motions that involve the whole protein, and local motions that involve the formation and breaking of intramolecular hydrogen bonds. The character of the MD trajectories can be described within the framework of rugged energy landscape dynamics. The MD trajectories sample multiple conformational minima, with basins in protein conformational space being sampled for a few hundred picoseconds, The trajectories of the system in configurational space can be described in terms of diffusion of a particle in real space with a waiting time distribution due to partial trapping in shallow minima. As a consequence of the hierarchical nature of the dynamics, the mean square displacement autocorrelation function, [\x(t) - x(0)\(2)], exhibits a power law dependence on time, with an exponent of around 0.5 for times shorter than 100 ps, and an exponent of 1.75 for longer times. This power law behavior indicates that the system exhibits suppressed diffusion (sub-diffusion) in sampling of configurational space at time scales shorter than 100 ps, and enhanced (super-diffusion) at longer time scales. The multi-basin feature of the trajectories is present at all temperatures simulated. Structural changes associated with inter-basin displacements correspond to collective motions of the Omega loops and coiled regions and relative motions of the alpha-helices as rigid bodies. Similar motions may be involved in experimentally observed amide hydrogen exchange. However, some groups showing large correlated motions do not expose the amino hydrogens to the solvent. We show that large fluctuations are not necessarily correlated to hydrogen exchange. For example, regions of the proteins forming alpha helices and turns show significant fluctuations, but as rigid bodies, and the hydrogen bonds involved in the formation of these structures do not break in proportion to these fluctuations. Proteins 1999;36:175-191. Published 1999 Wiley-Liss,Inc.(dagger) C1 Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. RP Garcia, AE (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, T10,MS K710, Los Alamos, NM 87545 USA. RI Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 59 TC 82 Z9 82 U1 2 U2 15 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD AUG 1 PY 1999 VL 36 IS 2 BP 175 EP 191 DI 10.1002/(SICI)1097-0134(19990801)36:2<175::AID-PROT4>3.0.CO;2-R PG 17 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 211YN UT WOS:000081189600004 PM 10398365 ER PT J AU Roy, SC Kissel, L Pratt, RH AF Roy, SC Kissel, L Pratt, RH TI Elastic scattering of photons SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID X-RAY-SCATTERING; ANGLE RAYLEIGH-SCATTERING; ATOMIC FORM-FACTORS; KEV GAMMA-RAYS; ANOMALOUS-SCATTERING; COHERENT-SCATTERING; CROSS-SECTIONS; 59.54-KEV PHOTONS; PB; SN AB Photon scattering from bound electrons of atoms, a component of the elastic photon-atom scattering amplitude called Rayleigh scattering, is discussed. General features of the many-body scattering amplitude and its partitioning into Rayleigh and Delbruck land nuclear) single-electron transition scattering amplitudes are examined. The use of the state-of-the-art precise second-order S-matrix calculations of Rayleigh scattering in terms of single-electron transition-amplitudes has led to significant progress in our understanding of the scattering process. The importance of relativistic, higher multipole, and bound-bound contributions in calculating anomalous scattering factor deviations from form factor amplitudes must be emphasized. Accurate interpolation of cross sections in the three-dimensional space of scattering angle, photon energy, and atomic number, utilizing the available published S-matrix data, has permitted extensive tabulation of differential scattering cross sections. S-matrix results may be compared with experiments to assess their validity; they may be compared with simpler but more approximate approaches. to identify the extent of the utility of such approaches and to develop simpler prescription schemes which can give results comparable to the S-matrix results. In spite of their many successes, the present second order S-matrix methods also have limitations and shortcomings, observed in certain recent experiments. We describe the explanation of these experiments in terms of a composite theory which also incorporates non-local exchange and correlation effects. We end with a discussion of other future issues. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Bose Inst, Dept Phys, Calcutta 700009, W Bengal, India. Univ Calif Lawrence Livermore Natl Lab, Div L41 5, Livermore, CA 94551 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RP Roy, SC (reprint author), Bose Inst, Dept Phys, Calcutta 700009, W Bengal, India. NR 71 TC 37 Z9 37 U1 2 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 56 IS 1-2 BP 3 EP 26 DI 10.1016/S0969-806X(99)00286-8 PG 24 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 251BZ UT WOS:000083425900002 ER PT J AU Bradley, DA Roy, SC Kissel, L Pratt, RH AF Bradley, DA Roy, SC Kissel, L Pratt, RH TI Anomalous scattering effects in elastic photon-atom scattering from biomedically important elements SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID X-RAY-DIFFRACTION; DIAGNOSTIC-RADIOLOGY; COMPUTED-TOMOGRAPHY; RAYLEIGH-SCATTERING; COMPTON-SCATTERING; COHERENT SCATTER; FORM-FACTORS; RADIATION; TISSUES; WATER AB In a variety of biomedical applications it has been demonstrated that elastic photon-atom scattering can be important. These include: solving for the crystal structure of a macromolecule, imaging, and radiation dose calculations. To the extent that scattering is significant, it is important to remember that there are a number of effects which go beyond the form-factor approximation. In this paper, we discuss what is presently known about the validity of form-factor approximations for predictions of elastic photon scattering by atoms. We quantify the uncertainty in form-factor theories for sample atoms of biomedical interest, including: carbon, oxygen, aluminum, calcium, iron, iodine and lead. The importance of effects that go beyond form-factor approximation is illustrated by demonstrating that errors can be introduced in using a simple form-factor-based scaling technique using scattering factors measured at one energy to predict scattering at another energy. These anomalous dispersion have been used extensively in recent years in studying structures of biological macromolecules, either in combination with or as an alternative to isomorphous replacement techniques. We present accurate, high precision anomalous scattering factors for a range of elements commonly used in macro-molecular structure studies, tabulated on a fixed grid interval in the energy range 1- to 100 keV. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Malaya, Dept Phys, Kuala Lumpur 50603, Malaysia. Bose Inst, Dept Phys, Calcutta 700009, W Bengal, India. Univ Calif Lawrence Livermore Natl Lab, Sci & Computat Dept, Livermore, CA 94551 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RP Bradley, DA (reprint author), Univ Malaya, Dept Phys, Kuala Lumpur 50603, Malaysia. NR 44 TC 11 Z9 11 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 56 IS 1-2 BP 175 EP 195 DI 10.1016/S0969-806X(99)00280-7 PG 21 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 251BZ UT WOS:000083425900011 ER PT J AU Takahashi, K Fujii, K Sawamura, S Jonah, CD AF Takahashi, K Fujii, K Sawamura, S Jonah, CD TI Density dependence of the Stokes shift and solvent reorganization energy in supercritical fluids SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 9th Tihany Symposium on Radiation Chemistry CY AUG 29-SEP 03, 1998 CL TATABANYA, HUNGARY ID ELECTRON-TRANSFER AB The Stokes shifts of coumarin 153 (C153) in CF3H, CO2 and C2H6 have been measured at several reduced densities (0.3-1.8). For C153 in CF3H, the shifts increase with a decrease in reduced density and show a maximum value at a reduced density of 0.5. In non-polar solvents, the shifts are not dramatically altered as a function of reduced density but slightly increase with a decrease in the reduced density. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Hokkaido Univ, Div Quantum Energy Engn, Sapporo, Hokkaido 060, Japan. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Takahashi, K (reprint author), Hokkaido Univ, Div Quantum Energy Engn, Sapporo, Hokkaido 060, Japan. RI Takahashi, Kenji/C-8846-2011; Takahashi, Kenji/F-4885-2014 NR 6 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 55 IS 5-6 BP 579 EP 581 DI 10.1016/S0969-806X(99)00249-2 PG 3 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 221YN UT WOS:000081755600020 ER PT J AU Coderre, JA Morris, GM Kalef-Ezra, J Micca, PL Ma, R Youngs, K Gordon, CR AF Coderre, JA Morris, GM Kalef-Ezra, J Micca, PL Ma, R Youngs, K Gordon, CR TI The effects of boron neutron capture irradiation on oral mucosa: evaluation using a rat tongue model SO RADIATION RESEARCH LA English DT Article ID P-BORONOPHENYLALANINE; ACCELERATED REPOPULATION; PROLIFERATION KINETICS; RADIATION RESPONSE; BOROCAPTATE SODIUM; BRAIN-TUMOR; SPINAL-CORD; LIP MUCOSA; THERAPY; EPITHELIUM AB The ventral surface of the tongue of male Fisher 344 rats was used to evaluate the response of oral mucosa to boron neutron capture irradiation. Three hours after i.p. injection of 700 mg/kg of the boron delivery agent p-boronophenylalanine (BPA), the boron concentrations in blood and tongue mucosal epithelium were approximately 21 and 23 mu g (10)B/g, respectively. The doses required to produce a 50% incidence of ulceration with X rays, the Brookhaven Medical Research Reactor thermal neutron beam alone, or the thermal neutron beam in the presence of BPA were 13.4 +/- 0.2, 4.2 +/- 0.1, and 3.0 +/- 0.1 Gy, respectively. Ulceration of the tongue was evident by 6 to 7 days after irradiation, irrespective of the irradiation modality; healing was related to dose and was relatively rapid (less than or equal to 19 days). Compared to 100 kVp X rays, the relative biological effectiveness factors were 3.2 for the thermal neutron beam and 4.9 for the products of the boron neutron capture reaction, (10)B(n,alpha)(7)Li. Oral mucosa is highly sensitive to BPA-mediated BNC irradiation and could be a dose-limiting normal tissue in BNCT of brain tumors, or if BPA-based BNCT is applied to the treatment of head and neck tumors. (C) 1999 by Radiation Research Society. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Univ Oxford, Churchill Hosp, Res Inst, Oxford OX3 7LJ, England. Univ Ioannina, Sch Med, Lab Med Phys, GR-45110 Ioannina, Greece. RP Coderre, JA (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. NR 36 TC 21 Z9 22 U1 0 U2 0 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD AUG PY 1999 VL 152 IS 2 BP 113 EP 118 DI 10.2307/3580083 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 224ZQ UT WOS:000081930500002 PM 10409319 ER PT J AU Scobel, JH Theofanous, TG Sorrell, SW AF Scobel, JH Theofanous, TG Sorrell, SW TI Application of the risk oriented accident analysis methodology (ROAMM) to severe accident management in the AP600 advanced light water reactor (vol 62, pg 51, 1998) SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Correction C1 Westinghouse Elect Corp, Pittsburgh, PA 15230 USA. Univ Calif Santa Barbara, Ctr Risk Studies & Safety, Santa Barbara, CA 93106 USA. US Dept Energy, Idaho Falls, ID 83401 USA. RP Scobel, JH (reprint author), Westinghouse Elect Corp, POB 355, Pittsburgh, PA 15230 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PD AUG PY 1999 VL 65 IS 2 BP 199 EP 199 DI 10.1016/S0951-8320(98)00094-5 PG 1 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 204FF UT WOS:000080752900009 ER PT J AU Fockenberg, C Bernstein, HJ Hall, GE Muckerman, JT Preses, JM Sears, TJ Weston, RE AF Fockenberg, C Bernstein, HJ Hall, GE Muckerman, JT Preses, JM Sears, TJ Weston, RE TI Repetitively sampled time-of-flight mass spectrometry for gas-phase kinetics studies SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID RADICALS; PHOTOLYSIS; CH3 AB An apparatus has been constructed to study radical-radical reactions in the gas phase. It consists of a tubular quartz reactor in which radicals are produced by flash photolysis using an excimer laser as light source. The composition of the gas mixture is analyzed in situ by photoionizing sampled gases using the vacuum ultraviolet emission of a hollow cathode lamp and subsequent time-of-flight mass spectrometry. A simple arrangement of grids at the entrance to the flight tube is used to interrupt the constant flux of ions by application of a combination of constant and pulsed voltages. Individual mass spectra can be taken at a repetition rate of around 20 kHz following each photolysis event. Signal counts from a specified number of consecutive mass spectra are fed into a 2 GHz multiscaler and accumulated as a sampling-time-indexed series of mass spectra. This allows simultaneous observation of the concentrations of multiple transient or stable species on a millisecond time scale. To achieve a suitable signal-to-noise ratio, signals were typically accumulated over several tens of thousands of laser shots at a pulse rate of 10-15 Hz. (C) 1999 American Institute of Physics. [S0034-6748(99)02708-2]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Fockenberg, C (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Muckerman, James/D-8752-2013; Sears, Trevor/B-5990-2013; Hall, Gregory/D-4883-2013 OI Sears, Trevor/0000-0002-5559-0154; Hall, Gregory/0000-0002-8534-9783 NR 8 TC 15 Z9 16 U1 2 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1999 VL 70 IS 8 BP 3259 EP 3264 DI 10.1063/1.1149944 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 221HE UT WOS:000081720900009 ER PT J AU Carlsten, BE AF Carlsten, BE TI Using the induced axial magnetic field to measure the root mean square beam size and beam density uniformity of an electron beam in an induction linac SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID EMITTANCE; GROWTH AB An intense electron beam in a solenoidal axial magnetic field rotates azimuthally, and generates a diamagnetic axial field that counteracts the applied field. However, the magnetic flux within the beam pipe is conserved over sufficiently short times, and this induced diamagnetic field must lead to an increase in the axial field outside the beam, which is measurable with a loop or an optical Faraday rotator. If the applied axial magnetic field is uniform across the beam pipe, the measurement directly leads to the rms transverse beam size. However, if the axial magnetic field has sinusoidal components, measurement of the diamagnetic field at two axial positions yields both the beam's rms transverse size and the beam's fourth radial moment. Comparison of these moments can give a figure of merit of the beam's density uniformity. (C) 1999 American Institute of Physics. [S0034-6748(99)00708-X]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Carlsten, BE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1999 VL 70 IS 8 BP 3308 EP 3313 DI 10.1063/1.1149909 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 221HE UT WOS:000081720900017 ER PT J AU Zhang, T Tang, BY Chen, QC Zeng, ZM Chu, PK Bilek, MMM Brown, IG AF Zhang, T Tang, BY Chen, QC Zeng, ZM Chu, PK Bilek, MMM Brown, IG TI Vacuum arc plasma transport through a magnetic duct with a biased electrode at the outer wall SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID CATHODIC ARC; DEPOSITION; FILTERS AB Metal plasma formed by a vacuum arc plasma source can be passed through a toroidal-section magnetic duct for the filtering of macroparticles from the plasma stream. In order to maximize the plasma transport efficiency of the filter the duct wall should be biased, typically to a positive voltage of about 10-20 V. In some cases it is not convenient to bias the duct, for example if the duct wall is part of the grounded vacuum system. However, a positively biased electrode inserted into the duct along its outer major circumference can serve a similar purpose. In this article, we describe our results confirming and quantifying this effect. We also show the parametric dependence of the duct transport on the experimental variables. (C) 1999 American Institute of Physics. [S0034-6748(99)01008-4]. C1 City Univ Hong Kong, Dept Phys & Mat Sci, Kowloon, Hong Kong. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chu, PK (reprint author), City Univ Hong Kong, Dept Phys & Mat Sci, 83 Tat Chee Ave, Kowloon, Hong Kong. RI Chu, Paul/B-5923-2013 OI Chu, Paul/0000-0002-5581-4883 NR 16 TC 20 Z9 20 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1999 VL 70 IS 8 BP 3329 EP 3331 DI 10.1063/1.1149913 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 221HE UT WOS:000081720900021 ER PT J AU Mills, GS Neuhauser, KS AF Mills, GS Neuhauser, KS TI Statistical evaluation of population data for calculation of radioactive material transport accident risks SO RISK ANALYSIS LA English DT Article DE accident risk; population distribution; RADTRAN; transportation; radioactive materials AB Calculation of accident dose-risk estimates with the RADTRAN code requires input data describing the population likely to be affected by the plume of radioactive material (RAM) released in a hypothetical transportation accident. In the existing model, population densities within 1/2 mile (0.8 km) of the route centerline are tabulated in three ranges (Rural, Suburban, and Urban). These population densities may be of questionable validity since the plume in the RADTRAN analysis is assumed to extend out to 120 km from the hypothetical accident site. We present a GIS-based population model which accounts for the actual distribution of population under a potential plume, and compare accident-risk estimates based on the resulting population densities with those based on the existing model. Results for individual points along a route differ greatly, but the cumulative accident risks for a sample route of a few hundred kilometers are found to be comparable, if not identical. We conclude, therefore, that for estimation of aggregate accident risks over typical routes of several hundred kilometers, the existing, simpler RADTRAN model is sufficiently detailed and accurate. C1 Sandia Natl Labs, Dept 6331, Albuquerque, NM 87185 USA. RP Mills, GS (reprint author), Sandia Natl Labs, Dept 6331, MS 0718, Albuquerque, NM 87185 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD AUG PY 1999 VL 19 IS 4 BP 613 EP 619 PG 7 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 248DX UT WOS:000083261000007 PM 10765425 ER PT J AU Kury, JW Breithaupt, RD Tarver, CM AF Kury, JW Breithaupt, RD Tarver, CM TI Detonation waves in trinitrotoluene SO SHOCK WAVES LA English DT Article DE detonation; reaction zone; trinitrotoluene; modeling; laser interferometry AB Fabry-Perot, ORVIS, and VISAR laser interferometry are used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper and tantalum discs accelerated by detonating trinitrotoluene (TNT) charges and of the interfaces between TNT detonation products and lithium fluoride crystals. TNT detonation reaction zone profiles are measured for self-sustaining detonation and piston supported overdriven (supracompressed) waves. The experimental records are compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The Ignition and Growth reactive flow model, which is based on the Zeldovich-von Neumann-Doring (ZND) theory of detonation, yields excellent agreement with the experimental records for TNT using an unreacted von Neumann spike pressure of 25 GPa, a reaction rate law which releases 90% of the chemical energy within 80 ns and the remaining 10% over an additional 200 ns, and a reaction product equation of state fit to cylinder test data assuming a Chapman-Jouguet pressure of 19 GPa. The late time energy release is attributed to diffusion controlled solid carbon particle formation. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Tarver, CM (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 21 TC 29 Z9 32 U1 0 U2 6 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD AUG PY 1999 VL 9 IS 4 BP 227 EP 237 DI 10.1007/s001930050160 PG 11 WC Mechanics SC Mechanics GA 233PK UT WOS:000082435100002 ER PT J AU Potok, TE Vouk, M Rindos, A AF Potok, TE Vouk, M Rindos, A TI Productivity analysis of object-oriented software developed in a commercial environment SO SOFTWARE-PRACTICE & EXPERIENCE LA English DT Article DE object-oriented; software development productivity ID REUSE; COST AB The introduction of object-oriented technology does not appear to hinder overall productivity on new large commercial projects, but nor does it seem to improve it in the first two product generations. In practice, the governing influence may be the business workflow, and not the methodology. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. N Carolina State Univ, Dept Comp Sci, Coll Engn, Raleigh, NC 27695 USA. Int Business Machines Corp, Dept CE6A, Res Triangle Pk, NC 27709 USA. RP Potok, TE (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 6010, Oak Ridge, TN 37830 USA. OI Potok, Thomas/0000-0001-6687-3435 NR 20 TC 4 Z9 4 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0038-0644 J9 SOFTWARE PRACT EXPER JI Softw.-Pract. Exp. PD AUG PY 1999 VL 29 IS 10 BP 833 EP 847 DI 10.1002/(SICI)1097-024X(199908)29:10<833::AID-SPE258>3.0.CO;2-P PG 15 WC Computer Science, Software Engineering SC Computer Science GA 229CC UT WOS:000082175100001 ER PT J AU Jenneman, GE Moffitt, PD Bala, GA Webb, RH AF Jenneman, GE Moffitt, PD Bala, GA Webb, RH TI Sulfide removal in reservoir brine by indigenous bacteria SO SPE PRODUCTION & FACILITIES LA English DT Article ID OIL-FIELD; NITRATE; INJECTION AB A field test was performed at the Coleville field to evaluate the ability of indigenous bacteria to remove sulfides from reservoir brine. Ammonium nitrate and sodium phosphate were injected continuously at two injectors for nearly 50 days. Sulfide levels at the two injectors declined by 42 to 100% and by as much as 50 to 60% at two adjacent producers. Concentrations of indigenous sulfide oxidizing, nitrate-reducing bacteria increased at injectors and producers while concentrations of sulfate-reducing bacteria remained unchanged or decreased slightly. Stimulation of indigenous beneficial bacteria has potential application as a cost-effective, low toxicity means to remove and control sulfides in reservoir brines. C1 Phillips Petr Co, Bartlesville, OK 74004 USA. Idaho Natl Engn & Environm Lab, Lockheed Martin Idaho Technol, Idaho Falls, ID USA. RP Jenneman, GE (reprint author), Phillips Petr Co, Bartlesville, OK 74004 USA. NR 17 TC 26 Z9 28 U1 1 U2 3 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR,, RICHARDSON, TX 75080 USA SN 1064-668X J9 SPE PROD FACIL JI SPE Prod. Fac. PD AUG PY 1999 VL 14 IS 3 BP 219 EP 225 PG 7 WC Engineering, Petroleum SC Engineering GA 227FN UT WOS:000082068500008 ER PT J AU Lin, CY Gelman, A Price, PN Krantz, DH AF Lin, CY Gelman, A Price, PN Krantz, DH TI Analysis of local decisions using hierarchical modeling, applied to home radon measurement and remediation SO STATISTICAL SCIENCE LA English DT Article DE Bayesian decision analysis; hierarchical models; small area decision problems; value of information ID LUNG-CANCER RISK; UNITED-STATES HOMES; INDOOR RADON; RESIDENTIAL-MOBILITY; SHORT-TERM; LONG-TERM; PREDICTIONS; SYSTEMS; RN-222; SAMPLE AB This paper examines the decision problems associated with measurement and remediation of environmental hazards, using the example of indoor radon (a carcinogen) as a case study. Innovative methods developed here include (1) the use of results from a previous hierarchical statistical analysis to obtain probability distributions with local variation in both predictions and uncertainties, (2) graphical methods to display the aggregate consequences of decisions by individuals and (3) alternative parameterizations for individual variation in the dollar value of a given reduction in risk. We perform cost-benefit analyses for a variety of decision strategies, as a function of home types and geography, so that measurement and remediation can be recommended where it is most effective. We also briefly discuss the sensitivity of policy recommendations and outcomes to uncertainty in inputs. For the home radon example, we estimate that if the recommended decision rule were applied to all houses in the United States, it would be possible to save the same number of lives as with the current official recommendations for about 40% less cost. C1 Columbia Univ, Dept Stat, New York, NY 10027 USA. Columbia Univ, Dept Biostat, New York, NY 10032 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Columbia Univ, Dept Psychol, New York, NY 10027 USA. RP Gelman, A (reprint author), Columbia Univ, Dept Stat, New York, NY 10027 USA. NR 48 TC 19 Z9 19 U1 4 U2 4 PU INST MATHEMATICAL STATISTICS PI HAYWARD PA IMS BUSINESS OFFICE-SUITE 7, 3401 INVESTMENT BLVD, HAYWARD, CA 94545 USA SN 0883-4237 J9 STAT SCI JI Stat. Sci. PD AUG PY 1999 VL 14 IS 3 BP 305 EP 328 PG 24 WC Statistics & Probability SC Mathematics GA 253YL UT WOS:000083584700004 ER PT J AU Van Hove, MA AF Van Hove, MA TI Atomic-scale surface structure determination: Comparison of techniques SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Asia-Pacific Surface and Interface Analysis Conference 1998 (APSIAC 98) CY NOV 30-DEC 04, 1998 CL SINGAPORE, SINGAPORE DE surface structure; structure determination; LEED; photoelectron diffraction; XAFS; XRD; ion scattering; STM ID ENERGY-ELECTRON-DIFFRACTION; X-RAY-DIFFRACTION; ENTROPY ALGORITHM; ION-SCATTERING; DIFFUSE LEED; RECONSTRUCTION; MICROSCOPY; SPECTROMICROSCOPY; INTENSITIES; INTERFACE AB This article reviews and speculates on the relative capabilities of major techniques for detailed structure determination of surfaces and interfaces. These techniques are primarily low-energy electron diffraction (LEED), x-ray diffraction (XRD), photoelectron diffraction (PD), x-ray absorption fine structure (XAFS), ion scattering CIS) and scanning tunneling microscopy (STM). Their use for more qualitative structural characterization is also briefly considered. The limits of their applicability to various types of surfaces and interfaces are explored: solid-gas, solid-liquid and solid-solid interfaces; non-crystalline surfaces (quasicrystalline, amorphous, liquid); and magnetic structures and imperfect overlayers on crystalline substrates. Copyright (C) 1999 John Whey & Sons, Ltd. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Van Hove, MA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Mailstop 66-200, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 36 TC 11 Z9 11 U1 1 U2 8 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD AUG PY 1999 VL 28 IS 1 BP 36 EP 43 DI 10.1002/(SICI)1096-9918(199908)28:1<36::AID-SIA614>3.3.CO;2-T PG 8 WC Chemistry, Physical SC Chemistry GA 234JZ UT WOS:000082482200008 ER PT J AU Avci, R Hagenston, AM Equall, NL Groenewold, GS Gresham, GL Dahl, DA AF Avci, R Hagenston, AM Equall, NL Groenewold, GS Gresham, GL Dahl, DA TI Ion extraction from insulating fibers in ToF-SIMS SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE ToF-SIMS; fiber; ion extraction AB Extraction of ions in a triple focusing time-of-flight secondary ion mass spectroscopy system is studied as a function of substrate potential with samples consisting of insulating dielectric fibers mounted on a metallic substrate. It is determined that ions extracted from the surfaces of the dielectric require, in general, a higher substrate potential than those extracted from the surface of the metallic substrate. Results are explained in terms of the electrostatic potential distribution in the extraction region and the dielectric properties of the fibers, Copyright (C) 1999 John Whey & Sons, Ltd. C1 Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Avci, R (reprint author), Montana State Univ, Dept Phys, EPS 264, Bozeman, MT 59717 USA. NR 7 TC 19 Z9 19 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD AUG PY 1999 VL 27 IS 8 BP 789 EP 796 PG 8 WC Chemistry, Physical SC Chemistry GA 229XR UT WOS:000082221500012 ER PT J AU Umble, EJ Seaman, JW Martz, HF AF Umble, EJ Seaman, JW Martz, HF TI A distribution-free Bayesian approach for determining the joint probability of failure of materials subject to multiple proof loads SO TECHNOMETRICS LA English DT Article DE beta priors; differences of beta variates; hypergeometric function; lumber; products of beta variates; slapper detonator ID VARIABLES; STRENGTH AB Survival of manufacturing materials or component parts may depend on two or more variables, and yet joint strength tests can be difficult to perform. For many such materials, multiple strength properties can be estimated only using destructive testing. This problem gives rise to a technique called proof loading-stressing units up to a prescribed load, destroying only the weaker units, and leaving the survivors for further tests. We propose a distribution-free Bayesian approach for estimating the probability of joint failure under two proof loads. Our method does not assume that proof-load survivors are undamaged. C1 Texas A&M Univ, Dept Stat, College Stn, TX 77843 USA. Baylor Univ, Dept Informat Syst, Waco, TX 76798 USA. Baylor Univ, Inst Stat, Waco, TX 76798 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Umble, EJ (reprint author), Texas A&M Univ, Dept Stat, College Stn, TX 77843 USA. NR 27 TC 0 Z9 0 U1 1 U2 3 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD AUG PY 1999 VL 41 IS 3 BP 183 EP 191 DI 10.2307/1270563 PG 9 WC Statistics & Probability SC Mathematics GA 218QA UT WOS:000081562100001 ER PT J AU Kyrpides, NC Olsen, GJ AF Kyrpides, NC Olsen, GJ TI Archaeal and bacterial hyperthermophiles - horizontal gene exchange or common ancestry? SO TRENDS IN GENETICS LA English DT Editorial Material ID ORIGIN; PROKARYOTES; LIFE C1 Univ Illinois, Dept Microbiol, Urbana, IL 61801 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Kyrpides, NC (reprint author), Univ Illinois, Dept Microbiol, 131 Burrill Hall, Urbana, IL 61801 USA. RI Kyrpides, Nikos/A-6305-2014 OI Kyrpides, Nikos/0000-0002-6131-0462 NR 12 TC 36 Z9 38 U1 0 U2 1 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0168-9525 J9 TRENDS GENET JI Trends Genet. PD AUG PY 1999 VL 15 IS 8 BP 298 EP 299 DI 10.1016/S0168-9525(99)01811-9 PG 2 WC Genetics & Heredity SC Genetics & Heredity GA 223CN UT WOS:000081822600003 PM 10431189 ER PT J AU Stougaard, J Szczyglowski, K de Bruijn, FJ Parniske, M AF Stougaard, J Szczyglowski, K de Bruijn, FJ Parniske, M TI Genetic nomenclature guidelines for the model legume Lotus japonicus SO TRENDS IN PLANT SCIENCE LA English DT Letter ID SYMBIOTIC MUTANTS C1 Aarhus Univ, Gene Express Lab, DK-8000 Aarhus C, Denmark. Michigan State Univ, MSU DOE Plant Res Lab, E Lansing, MI 48824 USA. Sainsbury Lab, Norwich NR4 7UH, Norfolk, England. RP Stougaard, J (reprint author), Aarhus Univ, Gene Express Lab, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark. RI Parniske, Martin/F-2202-2011 OI Parniske, Martin/0000-0001-8561-747X NR 6 TC 8 Z9 9 U1 1 U2 1 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 1360-1385 J9 TRENDS PLANT SCI JI Trends Plant Sci. PD AUG PY 1999 VL 4 IS 8 BP 300 EP 301 DI 10.1016/S1360-1385(99)01453-3 PG 2 WC Plant Sciences SC Plant Sciences GA 222JQ UT WOS:000081781500008 ER PT J AU O'Connor, TP Field, R Fischer, D Rovansek, R Pitt, R Clark, S Lama, M AF O'Connor, TP Field, R Fischer, D Rovansek, R Pitt, R Clark, S Lama, M TI Urban wet-weather flow SO WATER ENVIRONMENT RESEARCH LA English DT Review ID POLYCYCLIC AROMATIC-HYDROCARBONS; SURFACE-WATER QUALITY; RELATIVE IMPORTANCE; PRECIPITATION DATA; HIGHWAY RUNOFF; HEAVY-METALS; GOLF-COURSES; WASTE-WATER; ROOF RUNOFF; RIVER SEINE C1 Oak Ridge Inst Sci & Educ Postgrad, US EPA,Natl Risk Management Res Lab, Wet Weather Flow Res Program,Water Supply & Water, Urban Watershed Management Branch, Cincinnati, OH USA. Univ Alabama, Dept Civil & Environm Engn, Birmingham, AL USA. RP O'Connor, TP (reprint author), US EPA, MS-104,2890 Woodbridge Ave, Edison, NJ 08837 USA. OI O'Connor, Thomas/0000-0002-5643-644X NR 373 TC 0 Z9 0 U1 1 U2 5 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 USA SN 1061-4303 J9 WATER ENVIRON RES JI Water Environ. Res. PD AUG PY 1999 VL 71 IS 5 BP 559 EP 583 DI 10.2175/106143099X133659 PG 25 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 230HZ UT WOS:000082246900006 ER PT J AU Stringfellow, WT Alvarez-Cohen, L AF Stringfellow, WT Alvarez-Cohen, L TI Evaluating the relationship between the sorption of PAHs to bacterial biomass and biodegradation SO WATER RESEARCH LA English DT Article DE polynuclear aromatic hydrocarbons (PAHs); bacterial biomass; biosorption; biodegradation ID HAZARDOUS ORGANIC POLLUTANTS; ACTIVATED-SLUDGE REACTORS; MICROBIAL BIOMASS; OPERATING-CONDITIONS; REMOVAL; BIOSORPTION; MICROPOLLUTANTS; HYDROCARBONS; PSEUDOMONADS; ADSORPTION AB Petroleum refinery wastewater containing polynuclear aromatic hydrocarbons (PAHs) are typically treated by biological processes in the United States. PAHs are recalcitrant, hydrophobic compounds and sorption to biological solids may be a significant mechanism for the removal of PAHs from refinery wastewater. The goal of this research was to investigate PAH sorption by bacterial biomass and examine the relationship between PAH biosorption and biodegradation. In this study, phenanthrene was used as a model PAH for biosorption studies and pyrene and fluoranthene were used as model compounds in biodegradation studies. It was found that phenanthrene biosorption varied with bacterial genus and species. Bacteria with the highest sorption capacity (K-P) belong to the Nocardioforms, organisms that often cause solids separation problems in activated sludge plants. Consequently, blooms of these difficult to settle organisms in refinery treatment plants could exasperate PAH releases to the environment. The measured sorption capacities were reproducible and appeared to represent surface sorption, based on the apparent competition between naphthalene and phenanthrene for sorption sites. Based on a comparison of K-P values, pure bacterial cultures can serve as valid models of biosorption by activated sludge MLSS. Finally it was found that PAH sequestration by high K-P, non-degraders has a significant impact on PAH biodegradation. The results of this study suggest that although biosorption can decrease the rate of PAH biodegradation in the short term, it can also result in the removal of PAHs from the wastewater and PAH retention in the treatment system where it may be ultimately biodegraded. This research improves our understanding of processes contributing to PAH degradation in petroleum refinery wastewater treatment plants. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RP Stringfellow, WT (reprint author), Lawrence Berkeley Lab, Ctr Environm Biotechnol, MS 70A-3317, Berkeley, CA 94707 USA. RI Stringfellow, William/O-4389-2015 OI Stringfellow, William/0000-0003-3189-5604 NR 33 TC 64 Z9 69 U1 1 U2 39 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD AUG PY 1999 VL 33 IS 11 BP 2535 EP 2544 DI 10.1016/S0043-1354(98)00497-7 PG 10 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 211VW UT WOS:000081183400008 ER PT J AU Gao, JW Skeen, RS AF Gao, JW Skeen, RS TI Glucose-induced biodegradation of cis-dichloroethylene under aerobic conditions SO WATER RESEARCH LA English DT Article DE dichloroethylene; cometabolism; glucose ID ANAEROBIC AQUIFER MICROCOSMS; REDUCTIVE DECHLORINATION; VINYL-CHLORIDE; METHANOGENIC CONDITIONS; COMETABOLIC DEGRADATION; CHLORINATED ORGANICS; OXIDIZING BACTERIA; AROMATIC-COMPOUNDS; MIXED CULTURES; TRICHLOROETHYLENE AB The capability of the simple carbohydrate, glucose, to stimulate aerobic biodegradation of cis-dichloroethylene (cis-DCE) was tested using a river sediment. Greater reductions in cis-DCE were observed in aerobic microcosms incubated with glucose than in either killed controls, bottles incubated with oxygen and no glucose, or bottles containing glucose and no oxygen. Two aquifer sediments from different geographic locations also showed similar trends in dichloroethylene reduction. A sediment-foe transfer culture from the original river sediment was further tested for cis-DCE degradation. Results indicate that cis-DCE losses coincide with an increase in chloride.ion concentration. The increase was equivalent to the amount of chloride that would be expected from the measured reduction in dichloroethylene and the release of two chlorides per cis-DCE. The possibility that methanotrophic or ammonia-oxidizing bacteria mediated dichloroethylene destruction was eliminated, because the sediment-free suspension culture showed no evidence of either activity. Hence, it appears that a new type of activity mediated the observed dichloroethylene transformation. The implications of these results on ill situ bioremediation of chloroethylenes are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Pacific Natl NW Lab, Richland, WA 99352 USA. RP Skeen, RS (reprint author), Pacific Natl NW Lab, Battelle Blvd,POB 999, Richland, WA 99352 USA. EM rod.skeen@pnl.gov NR 46 TC 7 Z9 14 U1 2 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD AUG PY 1999 VL 33 IS 12 BP 2789 EP 2796 DI 10.1016/S0043-1354(98)00502-8 PG 8 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 226PC UT WOS:000082027500005 ER PT J AU Huang, K Tsang, YW Bodvarsson, GS AF Huang, K Tsang, YW Bodvarsson, GS TI Simultaneous inversion of air-injection tests in fractured unsaturated tuff at Yucca Mountain SO WATER RESOURCES RESEARCH LA English DT Article ID POROUS-MEDIA; GAS-TRANSPORT; FLUID-FLOW; MODEL; NETWORKS; ZONE; ROCK; PERMEABILITY; CALIBRATION; MECHANISMS AB Air-injection tests are being used to characterize the flow characteristics of the fractured volcanic tuffs at Yucca Mountain, Nevada, the proposed site for a high-level nuclear waste repository. As the air component flows mainly in the heterogeneous fracture system, air-injection tests can be used to determine the hydrological properties and parameters of the fracture networks. In situ air-injection tests have been carried out in 30 boreholes drilled in a fractured rock block of 13 x 21.5 x is m(3) in the underground facility at Yucca Mountain. These in situ field tests consist of a constant rate flow injection in one of the boreholes, while the pressure response is monitored in all 30 boreholes of the rock block. This paper presents a simultaneous inversion for 21 air-injection tests in 21 separate boreholes using TOUGH2, a three-dimensional numerical code for multiphase, multicomponent transport [Pruess, 1991; Pruess et al., 1996]. Spatially variable fracture permeability is used as an adjustable parameter to fit the measured pressure responses. For most of the pneumatic experiments the calculated pressure changes match the measured data well. Estimated permeabilities range over 5 orders of magnitude, from 10(-15) to 8 X 10(-11) m(2), indicating large spatial variability in permeability of the heterogeneous fracture system. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Div Earth Sci, Berkeley, CA USA. RP Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. EM khuang@frk.com; ytsang@lbl.gov; GSBodvarsson@lbl.gov NR 42 TC 20 Z9 21 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 EI 1944-7973 J9 WATER RESOUR RES JI Water Resour. Res. PD AUG PY 1999 VL 35 IS 8 BP 2375 EP 2386 DI 10.1029/1999WR900120 PG 12 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 221FC UT WOS:000081712500009 ER PT J AU Chilakapati, A Yabusaki, S AF Chilakapati, A Yabusaki, S TI Nonlinear reactions and nonuniform flows SO WATER RESOURCES RESEARCH LA English DT Article ID STOCHASTIC-CONVECTIVE TRANSPORT; HYPERBOLIC CONSERVATION-LAWS; HIGH-RESOLUTION SCHEMES; TRANSFER-FUNCTION MODEL; ZERO-ORDER PRODUCTION; SOLUTE TRANSPORT; POROUS-MEDIA; 1ST-ORDER DECAY; DISPLACEMENTS; STREAMTUBES AB Analytic solutions are developed for the advection-reaction problem with nonuniform flows and nonlinear reactions. We consider a stratified flow field and a flow field due to the operation of an injection-extraction pair of wells in a homogeneous medium. In each case we derive the transfer function for transport between a pair of surfaces in the flow field. We consider linear/nonlinear aqueous kinetics and the nonlinear equilibrium adsorption of a Langmuir radionuclide with decay. Using a stream tube concept in conjunction with these transfer functions, we develop analytic solutions to the flux-averaged concentration response of these reactive solutes. Resident concentrations are obtained by solving a simpler batch reaction system in place of coupled partial differential equations. We use these solutions to evaluate two numerical approaches. One of them is based on an operator-split approach that employs a conventional finite difference scheme with total variation diminishing fluxes for the advection operator. The other is based on the use of advected particles to compute a numerical approximation of the transfer function. We consider a boundary-value problem and establish that the particle-tracking approach yields near-analytic solutions for both the flux-averaged and resident concentrations. We consider an initial-value problem and evaluate the "dilution index" [Kitanidis, 1994] associated with the advective flow field and the numerical scheme. A flow field that highly distorts a plume and increases its surface area exhibits a larger dilution index, and most numerical schemes for transport in such a flow field suffer larger numerical dispersion. For linear reactions the predicted amount of plume degradation is unaffected by plume deformation, while the errors in predictions for nonlinear reactions increase as the plume deformation increases. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Chilakapati, A (reprint author), Pacific NW Lab, POB 999,Mail Stop K9-36, Richland, WA 99352 USA. NR 39 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD AUG PY 1999 VL 35 IS 8 BP 2427 EP 2438 DI 10.1029/1999WR900146 PG 12 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 221FC UT WOS:000081712500013 ER PT J AU Brooks, JA Garrison, WM AF Brooks, JA Garrison, WM TI Weld microstructure development and properties of precipitation-strengthened martensitic stainless steels SO WELDING JOURNAL LA English DT Article ID SOLIDIFICATION; CRACKING AB The weld microstructural evolution, mechanical properties and solidification cracking susceptibility of three precipitation-strengthened martensitic stainless steels - PH 13-8 Mo, Custom 450 and 15-5 PH - were investigated. Liquid tin quenching of gas tungsten are welds revealed that all th ree welds solidified as single-phase ferrite with a high degree of microsegregation. However, during further solidification and cooling almost complete homogenization occurred as a result of solid-state diffusion. The welds in all three alloys exhibited good resistance to solidification cracking and generally exhibited tensile and impact properties similar to those of the base metal. However, in almost all cases, the weld Charpy impact energies were somewhat less than those of the base metals. The cracking behavior and mechanical properties are discussed in terms of microstructural evolution. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. RP Brooks, JA (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 28 TC 6 Z9 6 U1 3 U2 5 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 USA SN 0043-2296 J9 WELD J JI Weld. J. PD AUG PY 1999 VL 78 IS 8 BP 280S EP 291S PG 12 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 223CL UT WOS:000081822400017 ER PT J AU Kane, SF Farland, AL Siewert, TA McCowan, CN AF Kane, SF Farland, AL Siewert, TA McCowan, CN TI Welding consumable development for a cryogenic (4 K) application SO WELDING JOURNAL LA English DT Article ID TOUGHNESS AB This paper summarizes the development and qualification of an appropriate welding consumable for a demanding cryogenic magnet application. It begins With a review of the research conducted on cryogenic fracture toughness of wrought and welded austenitic stainless steels. This research shows that certain elements of the composition have a powerful effect upon the steel's fracture toughness at 4 K. In particular, the higher oxygen content in the weld manifests itself as inclusions, which have a severe detrimental effect upon the fracture toughness. This one factor accounts for most of the difference in toughness between wrought and weld materials of similar composition, and is a function of the weld process. Also, welds enriched with manganese and nickel have demonstrated improved fracture toughness. These discoveries were combined in the development of a nitrogen- and manganese-modified, high-nickel stainless-steel alloy. It produced gas metal are welds with superior cryogenic mechanical properties (yield strength near 900 MPa at 4 K and a Charpy V-notch impact energy near 140 J at 76 K) when the procedures were modified to reduce the oxygen content. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Natl Inst Stand & Technol, Boulder, CO USA. RP Kane, SF (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 21 TC 7 Z9 7 U1 0 U2 4 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 USA SN 0043-2296 J9 WELD J JI Weld. J. PD AUG PY 1999 VL 78 IS 8 BP 292S EP 300S PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 223CL UT WOS:000081822400018 ER PT J AU Abebe, A Demissie, D Goudsmit, J Brouwer, M Kuiken, CL Pollakis, G Schuitemaker, H Fontanet, AL de Wit, TFR AF Abebe, A Demissie, D Goudsmit, J Brouwer, M Kuiken, CL Pollakis, G Schuitemaker, H Fontanet, AL de Wit, TFR TI HIV-1 subtype C syncytium- and non-syncytium-inducing phenotypes and coreceptor usage among Ethiopian patients with AIDS SO AIDS LA English DT Article DE HIV-1; C-subtype; AIDS; SI; NSI; coreceptor; Ethiopia ID HUMAN-IMMUNODEFICIENCY-VIRUS; BIOLOGICAL PHENOTYPE; GENOTYPIC CHARACTERISTICS; TYPE-1 INFECTION; VIRAL PHENOTYPE; ADDIS-ABABA; T-CELL; INDIVIDUALS; CAPACITY; CCR5 AB Objective: To assess syncytium-inducing (SI) and non-syncytium-inducing (NSI) frequencies, coreceptor usage and gp120 V3 sequences of HIV-1 isolates from Ethiopian AIDS patients. Patients: Cross-sectional study on 48 hospitalized AIDS patients (CD4 T cells < 200 x 10(6) cell/l) with stage III or IV of the WHO staging system for HIV-1 infection and disease. Methods: Peripheral blood mononuclear cells (PBMC) from all 48 patients were tested by MT-2 assay to determine SI/NSI phenotypes. Lymphocyte subsets were enumerated using Coulter counting and FACScan analysis. Viral load determination used a nucleic acid sequence-based amplification assay (NASBA). Coreceptor usage of HIV-1 biological clones was measured using U87 CD4/chemokine receptor transfectants and phytohemaggrutinin-stimulated PBMC of healthy donors with wildtype CCR5 and homozygous mutation CCR5 Delta 32 (a 32 base-pair deletion in CCR5). Reverse transcriptase polymerase chain reaction sequencing was performed on the third variable region (V3) of the HIV-1 gene gp120. Sequence alignments were done manually; phylogenetic analyses used PHYLIP software packages. Results: SI viruses were detected for 3/48 (6%) AIDS patients only. Lower mean absolute CD4 counts were determined in patients with SI virus compared with NSI (P = 0.04), but no differences in viral load were observed. All patients were found to be infected with HIV-1 subtype C, based on V3 sequencing. NSI biological clones used CCR5 as coreceptor; SI biological clones used CXCR4 and/or CCR5 and/or CCR3. Conclusions: Ethiopian patients with HIV-1 C-subtype AIDS harbour a remarkably low frequency of SI phenotype viruses. Coreceptor usage of these viruses correlates with their biological phenotypes. (C) 1999 Lippincott Williams & Wilkins. C1 Ethiopian Hlth & Nutr Res Inst, Ethiopian Netherlands AIDS Res Project, Addis Ababa, Ethiopia. Univ Addis Ababa, Fac Nat Sci, Dept Biol, Addis Ababa, Ethiopia. Univ Amsterdam, Acad Med Ctr, Dept Human Retrovirol, NL-1105 AZ Amsterdam, Netherlands. Sanquin Blood Supply Fdn, Dept Clin Viral Immunol, CLB, Amsterdam, Netherlands. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Abebe, A (reprint author), Ethiopian Hlth & Nutr Res Inst, Ethiopian Netherlands AIDS Res Project, POB 1242, Addis Ababa, Ethiopia. NR 53 TC 124 Z9 125 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0269-9370 J9 AIDS JI Aids PD JUL 30 PY 1999 VL 13 IS 11 BP 1305 EP 1311 DI 10.1097/00002030-199907300-00006 PG 7 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 221JD UT WOS:000081723200006 PM 10449282 ER PT J AU Mittler, JE Markowitz, M Ho, DD Perelson, AS AF Mittler, JE Markowitz, M Ho, DD Perelson, AS TI Improved estimates for H1V-1 clearance rate and intracellular delay SO AIDS LA English DT Letter ID DYNAMICS IN-VIVO; IMMUNODEFICIENCY-VIRUS TYPE-1; VIRAL DYNAMICS; INFECTION; LYMPHOCYTES; EXPRESSION; THERAPY C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10021 USA. RP Mittler, JE (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RRO6555]; PHS HHS [A 140387] NR 15 TC 60 Z9 63 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0269-9370 J9 AIDS JI Aids PD JUL 30 PY 1999 VL 13 IS 11 BP 1415 EP 1417 DI 10.1097/00002030-199907300-00023 PG 3 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 221JD UT WOS:000081723200022 PM 10449298 ER PT J AU Asmis, KR Taylor, TR Neumark, DM AF Asmis, KR Taylor, TR Neumark, DM TI Electronic structure of indium phosphide clusters: anion photoelectron spectroscopy of InxPx- and Inx+1Px- (x=1-13) clusters SO CHEMICAL PHYSICS LETTERS LA English DT Article ID INP QUANTUM DOTS; KINETIC-ENERGY SPECTROSCOPY; GALLIUM-ARSENIDE CLUSTERS; SEMICONDUCTOR CLUSTERS; SILICON; PHOTODETACHMENT; CONFINEMENT; GERMANIUM; SPECTRA; SIZE AB Photoelectron spectra for indium phosphide (InP) cluster anions comprised of up to 27 atoms were measured at a photodetachment wavelength of 266 nm. Results are presented for cluster anions of both stoichiometric and non-stoichiometric composition (InxPx-, Inx+1Px-; x = 1-13). In3P3 exhibits the lowest electron affinity (EA) of all the clusters studied, indicating a particularly stable neutral species. The EAs of the stoichiometric clusters are considerably lower than those of the corresponding non-stoichiometric clusters, suggesting the presence of closed-shell ground states for the neutral InxPx clusters. Remarkable agreement between the experimental EAs and those derived from calculations on quantum dots is found. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Neumark, DM (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 35 TC 47 Z9 48 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUL 30 PY 1999 VL 308 IS 5-6 BP 347 EP 354 DI 10.1016/S0009-2614(99)00671-5 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 221MV UT WOS:000081731600001 ER PT J AU Yee, HC Torczynski, JR Morton, SA Visbal, MR Sweby, PK AF Yee, HC Torczynski, JR Morton, SA Visbal, MR Sweby, PK TI On spurious behavior of CFD simulations SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE computational fluid dynamics; numerical simulation; spurious behavior ID STATE NUMERICAL-SOLUTIONS; NONLINEAR DIFFERENTIAL-EQUATIONS; BACKWARD-FACING STEP; REACTION-CONVECTION EQUATIONS; COMPUTATIONAL FLUID-DYNAMICS; GLOBAL ASYMPTOTIC-BEHAVIOR; ERROR CONTROL; 2-DIMENSIONAL FLOW; SOURCE TERMS; STABILITY AB Spurious behavior in underresolved grids and/or semi-implicit temporal discretizations for four computational fluid dynamics (CFD) simulations are studied. The numerical simulations consist of (a) a 1-D chemically relaxed non-equilibrium flow model, (b) the direct numerical simulation (DNS) of 2D incompressible flow over a backward facing step, (c) a loosely coupled approach for a 2D fluid-structure interaction, and (d) a 3D unsteady compressible flow simulation of vortex breakdown on delta wings. These examples were chosen based on their non-apparent spurious behaviors that were difficult to detect without extensive grid and/or temporal refinement studies and without some knowledge from dynamical systems theory. Studies revealed the various possible dangers of misinterpreting numerical simulation of realistic complex flows that are constrained by available computing power. In large scale computations, underresolved grids, semi-implicit procedures, loosely coupled implicit procedures, and insufficiently long-time integration in DNS are most often unavoidable. Consequently, care must be taken in both computation and in interpretation of the numerical data. The results presented confirm the important role that dynamical systems theory can play in the understanding of the non-linear behavior of numerical algorithms and in aiding the identification of the sources of numerical uncertainties in CFD. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. USAF, Wright Lab, CFD Res Branch, Wright Patterson AFB, OH 45433 USA. Univ Reading, Dept Math, Reading RG6 2AX, Berks, England. RP Yee, HC (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 45 TC 16 Z9 16 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD JUL 30 PY 1999 VL 30 IS 6 BP 675 EP 711 DI 10.1002/(SICI)1097-0363(19990730)30:6<675::AID-FLD857>3.0.CO;2-V PG 37 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA 220TQ UT WOS:000081683900004 ER PT J AU Halpern, MB Schwartz, C AF Halpern, MB Schwartz, C TI The algebras of large N matrix mechanics SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article ID QUENCHED MOMENTUM PRESCRIPTION; LATTICE GAUGE-THEORY; MASTER FIELD; MODEL; VARIABLES; LIMIT; QCD AB Extending early work, we formulate the large N matrix mechanics of general bosonic, fermionic and supersymmetric matrix models, including Matrix theory: the Hamiltonian framework of large N matrix mechanics provides a natural setting in which to study the algebras of the large N limit, including (reduced) Lie algebras, (reduced) supersymmetry algebras and free algebras. We find in particular a broad array of new free algebras which we call symmetric Cuntz algebras, interacting symmetric Cuntz algebras, symmetric Bose/Fermi/Cuntz algebras and symmetric Cuntz superalgebras, and we discuss the role of these algebras in solving the large N theory. Most important, the interacting Cuntz algebras are associated to a set of new (hidden!) local quantities which are generically conserved only at large N. A number of other new large N phenomena are also observed, including the intrinsic nonlocality of the (reduced) trace class operators of the theory and a closely related large N field identification phenomenon which is associated to another set (this time nonlocal) of new conserved quantities at large N. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM halpern@physics.berkeley.edu NR 47 TC 12 Z9 12 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X EI 1793-656X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUL 30 PY 1999 VL 14 IS 19 BP 3059 EP 3119 DI 10.1142/S0217751X99001482 PG 61 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 227EQ UT WOS:000082065700006 ER PT J AU Lee, JH Baker, TJ Mahal, LK Zabner, J Bertozzi, CR Wiemer, DF Welsh, MJ AF Lee, JH Baker, TJ Mahal, LK Zabner, J Bertozzi, CR Wiemer, DF Welsh, MJ TI Engineering novel cell surface receptors for virus-mediated gene transfer SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID SIALIC-ACID; IN-VIVO; ADENOVIRUS; BIOSYNTHESIS; EFFICIENCY; INHIBITION; DELIVERY; VECTORS; PATHWAY AB The absence of viral receptors is a major barrier to efficient gene transfer in many cells. To overcome this barrier, we developed an artificial receptor based on expression of a novel sugar, We fed cells an unnatural monosaccharide, a modified mannosamine that replaced the acetyl group with a levulinate group (ManLev), ManLev was metabolized and incorporated into cell-surface glycoconjugates. The synthetic sugar decorated the cell surface with a unique ketone group that served as a foundation on which we built an adenovirus receptor by covalently binding biotin hydrazide to the ketone. The artificial receptor enhanced adenoviral vector binding and gene transfer to cells that are relatively resistant to adenovirus infection. These data are the first to suggest the feasibility of a strategy that improves the efficiency of gene transfer by using the biosynthetic machinery of the cell to engineer novel sugars on the cell surface. C1 Univ Iowa, Coll Med, Howard Hughes Med Inst, Iowa City, IA 52242 USA. Univ Iowa, Dept Internal Med, Iowa City, IA 52242 USA. Univ Iowa, Dept Physiol & Biophys, Iowa City, IA 52242 USA. Univ Iowa, Dept Chem, Iowa City, IA 52242 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Welsh, MJ (reprint author), Univ Iowa, Coll Med, Howard Hughes Med Inst, 500 EMRB, Iowa City, IA 52242 USA. FU NIDDK NIH HHS [DK25295] NR 20 TC 72 Z9 73 U1 0 U2 4 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUL 30 PY 1999 VL 274 IS 31 BP 21878 EP 21884 DI 10.1074/jbc.274.31.21878 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 221HF UT WOS:000081721100060 PM 10419507 ER PT J AU Eagle, AA George, GN Tiekink, ERT Young, CG AF Eagle, AA George, GN Tiekink, ERT Young, CG TI Generation and biomimetic chemistry of tungsten-dithiolene complexes containing the hydrotris(3,5-dimethylpyrazol-l-yl)borate ligand SO JOURNAL OF INORGANIC BIOCHEMISTRY LA English DT Article DE dithiolene; tungsten; tungsten enzyme; dithiobis(thieno)quinoxaline; urothione; hyperthermophile ID ABSORPTION FINE-STRUCTURE; CRYSTAL-STRUCTURE; MOLYBDENUM-COFACTOR; XANTHINE-OXIDASE; SULFITE OXIDASE; 1,2-DITHIOLENE COMPLEXES; RHODOBACTER-CAPSULATUS; ANGSTROM RESOLUTION; CONTAINING ENZYMES; FUNCTIONAL-GROUP AB Reactions of bis(thio)-W(VI) complexes, LWS2X (L = hydrotris(3,5-dimethylpyrazol-1-yl)borate, X = monoanion), with alkynes produce dithiolene complexes, LWX(dithiolene). The synthesis and characterization of orange LW(OPh) {S2C2(CO2Me)(2)} (1) and burgundy-red LW(SePh) {S2C2(Ph)(2-quinoxalinyl)} (2) and the X-ray crystal structure of 1.0.5CH(2)Cl(2), are described in detail. Crystals of 1.0.5CH(2)Cl(2) are orthorhombic, space group Pbcn, with a = 29.826(6), b = 13.291(4), c = 16.078(3) Angstrom, V = 6373(5) Angstrom(3), and Z = 8. The six-coordinate, distorted-octahedral complex features a tridentate L ligand, a monodentate phenoxide ligand, and a bidentate dithiolene ligand. The short W-S bonds (2.267(4) and 2.279(4) Angstrom) and the parameters associated with the phenoxide ligand (W-O = 1.850(8) Angstrom, W-O-C = 146(1)degrees), point to a considerable degree of W-ligand multiple bonding in the [W(OPh) (dithiolene)](+) unit. For 2, W-Se and average W-S distances of 2.49(2) Angstrom and 2.30(2) ii, respectively, have been obtained from EXAFS studies. The formation of yellow 3,3'-dithiobis [2-(phenyl)thieno[2,3-b]quinoxaline] (3) upon oxidation of 2 supports the likely generation of urothione upon oxidative degradation of molybdopterin-containing tungsten enzymes from hyperthermophilic organisms. (C) 1999 Elsevier Science Inc. All rights reserved. C1 Univ Melbourne, Sch Chem, Parkville, Vic 3052, Australia. Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. Univ Adelaide, Dept Chem, Adelaide, SA 5005, Australia. RP Young, CG (reprint author), Univ Melbourne, Sch Chem, Parkville, Vic 3052, Australia. EM c.g.young@chemistry.unimelb.edu.au RI George, Graham/E-3290-2013 NR 59 TC 17 Z9 17 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0162-0134 EI 1873-3344 J9 J INORG BIOCHEM JI J. Inorg. Biochem. PD JUL 30 PY 1999 VL 76 IS 1 BP 39 EP 45 DI 10.1016/S0162-0134(99)00106-3 PG 7 WC Biochemistry & Molecular Biology; Chemistry, Inorganic & Nuclear SC Biochemistry & Molecular Biology; Chemistry GA 243WQ UT WOS:000083020800005 PM 10530005 ER PT J AU Jones, KA Shah, PB Kirchner, KW Lareau, RT Wood, MC Ervin, MH Vispute, RD Sharma, RP Venkatesan, T Holland, OW AF Jones, KA Shah, PB Kirchner, KW Lareau, RT Wood, MC Ervin, MH Vispute, RD Sharma, RP Venkatesan, T Holland, OW TI Annealing ion implanted SiC with an AlN cap SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT 2nd European Conference on Silicon Carbide and Related Materials (ECSCRM 98) CY SEP 02-04, 1998 CL MONTPELLIER, FRANCE SP Univ Montpellier II, Ctr Nat Recher Scientif, Conseil Reg Languedoc Roussillon, Conseil Gen Herault, Dist Agglomer Montpellier, European Union EuroConference & TMR Programmes, U S Army & European Res Off, Delegat Gen Armement, Aixtron AG, Cree Res Inc, Emcore Corp, Epigress AB, E P S Schlumberger, Ion Beam Serv, Omicron EURL, Schneider Elect, SiCrystal AG, Sterling Semiconductor, Thomson LCR DE ion; AlN cap; SiC wafer ID SILICON-CARBIDE; NITROGEN IMPLANTS; HIGH-TEMPERATURE; DEPOSITION; SIC(0001); OXIDATION; NITRIDE; ALPHA; AIN AB An AlN cap was used to try to prevent the preferential evaporation of Si during the high temperature anneals required to activate N implanted into a SiC substrate. The process was essentially successful as the electrical measurements showed that the resistivity continued to decrease with increasing annealing temperatures up to 1600 degrees C and times up to 120 min. The changes were, however, marginal when compared to a 1500 degrees C, 30 min anneal suggesting that this anneal would be sufficient to activate most of the N implants. There is evidence for a small amount of Si being lost near the surface. This could occur where the AlN pulled away locally from the SIC wafer; this effect was stronger for patterned substrates where stress concentrations can occur at steps. For the most part, however, the SiC surface retained its integrity even during the process of removing the AIN film with a hot KOH etch. Also, there was no evidence that Al from the AIN contaminated the N implanted region by diffusing in during the anneals. The surface of the AIN retained its integrity during the anneal although topographical changes suggested that considerable atomic motion had occurred. This coincided with the formation of an amorphous AIN layer in the film. (C) 1999 Elsevier Science S.A. All rights reserved. C1 USA, Res Lab, SEDD, AMSRL,SE,RL, Adelphi, MD 20783 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Jones, KA (reprint author), USA, Res Lab, SEDD, AMSRL,SE,RL, Adelphi, MD 20783 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 25 TC 27 Z9 28 U1 3 U2 9 PU ELSEVIER SCIENCE SA 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 JUL 30 PY 1999 VL 61-2 BP 281 EP 286 DI 10.1016/S0921-5107(98)00518-2 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 230CT UT WOS:000082234800058 ER PT J AU Touryan, KJ AF Touryan, KJ TI Science and "truth" SO SCIENCE LA English DT Letter C1 US DOE, Technol Transfer Off, Natl Renewable Energy Lab, Washington, DC 20585 USA. RP Touryan, KJ (reprint author), US DOE, Technol Transfer Off, Natl Renewable Energy Lab, Washington, DC 20585 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 30 PY 1999 VL 285 IS 5428 BP 663 EP 663 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 222CD UT WOS:000081765100018 PM 10454917 ER PT J AU Turner, JA AF Turner, JA TI A realizable renewable energy future SO SCIENCE LA English DT Editorial Material AB The ability of renewable resources to provide all of society's energy needs is shown by using the United States as an example. Various renewable systems are presented, and the issues of energy payback, carbon dioxide abatement, and energy storage are addressed. Pathways for renewable hydrogen generation are shown, and the implementation of hydrogen technologies into the energy infrastructure is presented. The question is asked, should money and energy be spent on carbon dioxide sequestration, or should renewable resources be implemented instead. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Turner, JA (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 13 TC 552 Z9 565 U1 31 U2 191 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 30 PY 1999 VL 285 IS 5428 BP 687 EP 689 DI 10.1126/science.285.5428.687 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 222CD UT WOS:000081765100041 ER PT J AU Nadeau, RM McEvilly, TV AF Nadeau, RM McEvilly, TV TI Fault slip rates at depth from recurrence intervals of repeating microearthquakes SO SCIENCE LA English DT Article ID SAN-ANDREAS FAULT; PARKFIELD; CALIFORNIA; EARTHQUAKES; PARAMETERS; FRICTION; ZONE AB Unique attributes in sequences of recurring, similar microearthquakes at Parkfield, California, provide a means for inferring slip rate at depth throughout the active fault surface from the time intervals between sequence events. Application of the method using an 11-year microseismicity record revealed systematic spatial and temporal changes in the slip rate that were synchronous with earthquake activity and other independent measures of fault-zone slip. If this phenomenon is found to be generally common behavior in active faults, it forms the basis for a method to monitor the changing strain field throughout a seismogenic fault zone. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley Seismol Lab, Berkeley, CA 94720 USA. RP Nadeau, RM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. NR 17 TC 169 Z9 180 U1 2 U2 10 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 30 PY 1999 VL 285 IS 5428 BP 718 EP 721 DI 10.1126/science.285.5428.718 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 222CD UT WOS:000081765100049 ER PT J AU Dupre, B Viers, J Dandurand, JL Polve, M Benezeth, P Vervier, P Braun, JJ AF Dupre, B Viers, J Dandurand, JL Polve, M Benezeth, P Vervier, P Braun, JJ TI Major and trace elements associated with colloids in organic-rich river waters: ultrafiltration of natural and spiked solutions SO CHEMICAL GEOLOGY LA English DT Article DE ultrafiltration; colloids; organic matter; complexation; strontium; isotope; stability constant; rare earth elements ID CONDITIONAL STABILITY-CONSTANTS; SOIL FULVIC-ACID; RAY-ABSORPTION SPECTROSCOPY; ION-SELECTIVE ELECTRODE; HUMIC SUBSTANCES; COPPER(II) COMPLEXATION; COMPLEXING CAPACITY; HUMATE COMPLEXES; BINDING-SITES; ALUMINUM AB This study presents the results of ultrafiltration experiments (0.20 mu m-300,000 Da-5000 Da-1000 Da) performed on natural rich-organic waters (30-40 mg l(-1) of dissolved organic carbon) sampled in wetland area of Cameroon (Nsimi-Zoetele site). A very strong decrease in all cation concentrations (major and trace elements) except Si was observed after filtration. Speciation calculations using data available in the literature for metal-humic substance complexation observations suggest that ultrafiltration performed on this water source at a pH of 4.74 induces a very strong retention of cations only weakly bound to humic substances in the aqueous solution [Viers, J., Dupre, B., Polve, M., Schott, J., Dandurand, J.L., Braun, J.J., 1997. Chemical weathering in the drainage basin of a tropical watershed (Nsimi-Zoetele site, Cameroon): comparison between organic-poor and organic-rich waters. Chem. Geol., 140, 181-206]. To minimize this artifact, ultrafiltration must be performed at low pH (= 3) or with the addition of high concentrations of a complexing metal (e.g., Lanthanum). The goal of these ultrafiltration experiments is to anticipate the affinity of several major and trace elements to form organo-metallic complexes with humic substances. Experiments using Sr and Ba isotopes at fixed ratios were entered in order to determine the exchangeable fraction of base cation. Natural Sr isotopic ratio (Sr-87/Sr-86) in different filtrates and retentates as well as isotopic ratios of Ba and Sr (Sr-86/Sr-84 and Ba-138/Ba-135) in spiked and filtered samples appear to remain constant. These results suggest that there is only one source of Sr in these natural waters and that it is present in an exchangeable form (i.e., free ion and/or complexed with organic matter). By analogy, we suppose that elements such as Ca or Mg are not present in organic or mineral colloids but in an exchangeable position. This is in agreement with the hypothesis of the filtration artifact. In the filtration experiment, performed at pH 3, more than 95% of Al, Ga, Fe, U, Th, Y and REEs, congruent to 50% of Cr and V, 25% of Cu, 10% of Co, and less than or equal to 5% of Ca, Mg, Na, K, Mn, Ba, Rb and Sr are complexed with organic material. According to the data gathered in this study and the results of speciation calculations, the order and the overall constants (log K) for the formation of metal-humate complexes are the following: Al, Ga, Fe, Th, U, Y, REEs (more than 7) >> Cr (5.5) >> Co (3) > Rb, Ba, Sr, Mn, Mg (approximate to 2). These data are obtained for both low ionic strength and low metal concentrations. Using the filtration experiment performed with an addition of La, we observe that REEs appear to be complexed with humic substances via two types of site. The first site has a strong affinity for the REEs but is not abundant. So the complexation by this site will be important when the REEs concentration is low. The second type of site is much more abundant but has a much smaller affinity for the complexation of REEs, This site will dominate when the REEs concentration is high. The first site remains unassigned but the second should be related to the carboxylic functional groups. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Toulouse 3, CNRS, UMR 5563, Equipe Geochim, F-31062 Toulouse, France. Oak Ridge Natl Lab, Oak Ridge, TN USA. Ctr Ecol & Syst Aquat Continentaux, F-31055 Toulouse, France. ORSTOM, TOA, Yaounde, Cameroon. RP Dupre, B (reprint author), Univ Toulouse 3, CNRS, UMR 5563, Equipe Geochim, 38 Rue 36 Ponts, F-31062 Toulouse, France. RI BENEZETH, Pascale/H-7969-2014; braun, jean jacques/C-5432-2013 OI BENEZETH, Pascale/0000-0002-1841-2383; braun, jean jacques/0000-0003-2979-6164 NR 72 TC 116 Z9 118 U1 0 U2 48 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JUL 29 PY 1999 VL 160 IS 1-2 BP 63 EP 80 DI 10.1016/S0009-2541(99)00060-1 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 217TZ UT WOS:000081516200004 ER PT J AU Deal, KA Davis, IA Mirzadeh, S Kennel, SJ Brechbiel, MW AF Deal, KA Davis, IA Mirzadeh, S Kennel, SJ Brechbiel, MW TI Improved in vivo stability of actinium-225 macrocyclic complexes SO JOURNAL OF MEDICINAL CHEMISTRY LA English DT Article ID POLYAMINO POLYCARBOXYLIC MACROCYCLES; AQUEOUS-SOLUTION; IN-VIVO; LIGAND; IONS; RADIOIMMUNOTHERAPY; RADIOLANTHANIDES; BIODISTRIBUTION; DISSOCIATION; AC-225 AB The favorable nuclear properties of actinium-225 (Ac-225) have led to proposal of this isotope for use in radioimmunotherapy. In an effort to reduce the toxicity of free Ac-225, a series of ligands were evaluated for stability in vivo. Loss of Ac-225 from acyclic chelating agents resulted in high liver uptake and poor whole body clearance. The macrocyclic ligands c-DOTA, PEPA, and HEHA were evaluated, and Ac-225-HEHA showed exceptional stability in vivo. Ac-225 chelated with EDTA, DTPA, DOTA, or PEPA permitted substantial accumulation of the radionuclide to the Liver, while the Ac-225-HEHA complex was essentially excreted within minutes of administration. The preparation of the ligands and radiolabeled complexes and the biodistribution results will be discussed. C1 NCI, NIH, Bethesda, MD 20892 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Brechbiel, MW (reprint author), NCI, NIH, 9000 Rockville Pike,Bldg 10 Room B3B69, Bethesda, MD 20892 USA. NR 36 TC 27 Z9 27 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-2623 J9 J MED CHEM JI J. Med. Chem. PD JUL 29 PY 1999 VL 42 IS 15 BP 2988 EP 2992 DI 10.1021/jm990141f PG 5 WC Chemistry, Medicinal SC Pharmacology & Pharmacy GA 222CJ UT WOS:000081765600027 PM 10425108 ER PT J AU Michael, JV Kumaran, SS Su, MC AF Michael, JV Kumaran, SS Su, MC TI Rate constants for CH3+O-2 -> CH3O+O at high temperature and evidence for H2CO+O-2 -> HCO+HO2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID POTENTIAL-ENERGY SURFACE; REFLECTED SHOCK-WAVES; THERMAL-DECOMPOSITION; CHEMICAL-KINETICS; METHYL RADICALS; GAS-PHASE; OXIDATION; COMBUSTION; ABSORPTION; MIXTURES AB The reaction of CH3 with Oz has been studied in a reflected shock tube apparatus between 1600 and 2100 K. CH3 was prepared from the fast thermal decomposition of CH3I, and O atom atomic resonance absorption spectrometry (ARAS) was used to observe absolute [O],. [CH3I](0) was sufficiently low so that most secondary reactions were negligible, allowing for unambiguous determination of the rate constant for CH3 + Oz CH3O + O. The rate constant expression for this reaction derived to match the experimental data is k = (3.90 +/- 0.40) x 10(-11) exp(-16858 +/- 1127 WT) cm(3) molecule(-1) s(-1). To explain O atom concentration buildup at longer times, a fast reaction between H2CO and Oz was postulated. Rate constants for this process were derived by fitting the long-time O atom profiles. Last, the four-center reaction CH3 + Oz --> CH2O + OH was found to be of negligible importance over the temperature range of the study. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Michael, JV (reprint author), Argonne Natl Lab, Div Chem, D-193,Bldg 200, Argonne, IL 60439 USA. RI Michael, Joe/E-3907-2010 NR 51 TC 25 Z9 25 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 29 PY 1999 VL 103 IS 30 BP 5942 EP 5948 DI 10.1021/jp9909457 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 222YU UT WOS:000081813600013 ER PT J AU Heiney, PA Stetzer, MR Mindyuk, OY DiMasi, E McGhie, AR Liu, H Smith, AB AF Heiney, PA Stetzer, MR Mindyuk, OY DiMasi, E McGhie, AR Liu, H Smith, AB TI Langmuir films of amphiphilic crown ethers SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID AIR-WATER-INTERFACE; LIQUID-CRYSTALLINE COMPOUNDS; ANCHORING TRANSITION; SELF-ORGANIZATION; MONOLAYERS; MOLECULES; AZACROWN; PHASES AB We have used X-ray reflectivity and grazing-incidence X-ray diffraction to study amphiphilic crown ethers 1 and 2 at the air-water interface. A new synthetic route was employed, which substantially reduced the level of impurities. Unlike previous studies of 1, we saw no evidence of a first-order lying-down to standing-up transition of the alkyl tails. We did observe in both compounds a gradual reorientation of the tails away from the interface as the film was compressed, followed by an irreversible collapse to a multilayer structure. The monolayer films have a fluid-like inplane structure, while the multilayer films are crystalline. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Univ Penn, Res Struct Matter Lab, Philadelphia, PA 19104 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RP Heiney, PA (reprint author), Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. NR 24 TC 10 Z9 10 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 29 PY 1999 VL 103 IS 30 BP 6206 EP 6214 DI 10.1021/jp990787j PG 9 WC Chemistry, Physical SC Chemistry GA 222YV UT WOS:000081813700008 ER PT J AU Gale, C Jeon, S Kapusta, J AF Gale, C Jeon, S Kapusta, J TI J/psi production and absorption in high energy proton-nucleus collisions SO PHYSICS LETTERS B LA English DT Article ID QUARK-GLUON PLASMA; SUPPRESSION; DEPENDENCE; PHOTOPRODUCTION AB Measured J/psi production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets are analyzed within a Glauber framework which takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of the J/psi on nucleons. The best representation is obtained for a coherence time of 0.5 fm/c, previously determined by Drell-Yan production in proton-nucleus collisions, and an absorption cross section of 3.6 mb, which is consistent with the value deduced from photoproduction of the J/psi, on nuclear targets. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Minnesota, Dept Phys & Astron, Minneapolis, MN 55455 USA. RP Gale, C (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ H3A 2T8, Canada. NR 17 TC 11 Z9 11 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 JUL 29 PY 1999 VL 459 IS 4 BP 455 EP 460 DI 10.1016/S0370-2693(99)00730-3 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 224PP UT WOS:000081907700006 ER PT J AU Gaillard, MK Nelson, B Wu, YY AF Gaillard, MK Nelson, B Wu, YY TI Gaugino masses in modular invariant supergravity SO PHYSICS LETTERS B LA English DT Article ID DYNAMICAL SUPERSYMMETRY BREAKING; EFFECTIVE LAGRANGIAN ANALYSIS; PAULI-VILLARS REGULARIZATION; COUPLED STRING THEORY; SUPERSTRING MODELS; LOOP CORRECTIONS; COUPLINGS; MATTER; COMPACTIFICATION; CONDENSATION AB We calculate gaugino masses in string-derived models with hidden-sector gaugino condensation. The linear multiplet formulation for the dilaton superfield is used to implement perturbative modular invariance. The contribution arising from quantum effects in the observable sector includes the term recently found in generic supergravity models. A much larger contribution is present if matter fields with Standard Model gauge couplings also couple to the Green-Schwarz counter term. We comment on the relation of our Kahler U(1) superspace formalism to other calculations. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, 50A-5101, Berkeley, CA 94720 USA. NR 42 TC 50 Z9 50 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUL 29 PY 1999 VL 459 IS 4 BP 549 EP 556 DI 10.1016/S0370-2693(99)00727-3 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 224PP UT WOS:000081907700019 ER PT J AU Bravina, LV Gorenstein, MI Zabrodin, EE Bass, SA Belkacem, M Bleicher, M Brandstetter, M Hofmann, M Soff, S Spieles, C Weber, H Stockerand, H Greiner, W AF Bravina, LV Gorenstein, MI Zabrodin, EE Bass, SA Belkacem, M Bleicher, M Brandstetter, M Hofmann, M Soff, S Spieles, C Weber, H Stockerand, H Greiner, W TI Equilibrium and non-equilibrium effects in nucleus-nucleus collisions SO PHYSICS LETTERS B LA English DT Article DE heavy ion collisions; QMD model; local thermodynamical equilibrium; equation of state; non-equilibrium effects ID HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; QCD PHASE-TRANSITION; HADRONIC MATTER; RELATIVISTIC HYDRODYNAMICS; FLUID-DYNAMICS; A+A COLLISIONS; MODEL; SPECTRA; DENSE AB Local thermal and chemical equilibration is studied for central A + A collisions at 10.7-160 AGeV in the Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). The UrQMD model exhibits strong deviations from local equilibrium at the high density hadron-string phase formed during the early stage of the collision. Equilibration of the hadron-resonance matter is established in the central cell of volume V = 125 fm(3) at later stages, t greater than or equal to 10 fm/c, of the resulting quasi-isentropic expansion. The thermodynamical functions in the cell and their time evolution are presented. Deviations of the UrQMD quasi-equilibrium state from the statistical mechanics equilibrium are found. They increase with energy per baryon and lead to a strong enhancement of the pion number density as compared to statistical mechanics estimates at SPS energies. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Frankfurt, Inst Theoret Phys, D-6000 Frankfurt, Germany. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow 119899, Russia. Bogolyubov Inst Theoret Phys, Kiev, Ukraine. Univ Tubingen, Inst Theoret Phys, D-7400 Tubingen, Germany. Duke Univ, Dept Phys, Durham, NC 27706 USA. Gesell Schwerionenforsch, D-6100 Darmstadt, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Bravina, LV (reprint author), Univ Frankfurt, Inst Theoret Phys, Robert Mayer Str 8, D-6000 Frankfurt, Germany. RI Bleicher, Marcus/A-2758-2010; OI Bass, Steffen/0000-0002-9451-0954 NR 59 TC 6 Z9 6 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 JUL 29 PY 1999 VL 459 IS 4 BP 660 EP 666 DI 10.1016/S0370-2693(99)00692-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 224PP UT WOS:000081907700036 ER PT J AU Appelshauser, H Bachler, J Bailey, SJ Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Billmeier, A Blyth, CO Bock, R Boimska, B Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Carr, LD Cebra, D Cooper, GE Cramer, JG Cristinziani, M Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Geist, W Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Prindle, DJ Puhlhofer, F Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Snellings, R Squier, GTA Stock, R Strobele, H Struck, C Susa, T Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Xu, N Yates, TA Zimanyi, J Zhu, XZ Zybert, R AF Appelshauser, H Bachler, J Bailey, SJ Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Billmeier, A Blyth, CO Bock, R Boimska, B Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Carr, LD Cebra, D Cooper, GE Cramer, JG Cristinziani, M Csato, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Geist, W Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Prindle, DJ Puhlhofer, F Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Seyerlein, J Sikler, F Skrzypczak, E Snellings, R Squier, GTA Stock, R Strobele, H Struck, C Susa, T Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wienold, T Wood, L Xu, N Yates, TA Zimanyi, J Zhu, XZ Zybert, R CA NA49 Collaboration TI Event-by-event fluctuations of average transverse momentum in central Pb plus Pb collisions at 158 GeV per nucleon SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; PB+PB COLLISIONS; EQUILIBRATION; AGEV; QCD AB We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb + Pb collisions at the CERN SPS. This measurement provides previously unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vicinity of the predicted QCD phase transition. We find that the observed variance of the event-by-event average transverse momentum is consistent with independent particle production modified by the known two-particle correlations due to quantum statistics and final state interactions and folded with the resolution of the NA49 apparatus. For two specific models of non-statistical fluctuations in transverse momentum limits are derived in terms of fluctuation amplitude. We show that a significant part of the parameter space for a model of isospin fluctuations predicted as a consequence of chiral symmetry restoration in a non-equilibrium scenario is excluded by our measurement. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Athens, Dept Phys, Athens, Greece. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA USA. Univ Birmingham, Birmingham, W Midlands, England. KFKI, Res Inst Particle & Nucl Phys, Budapest, Hungary. CERN, Geneva, Switzerland. Inst Nucl Phys, Krakow, Poland. Gesell Schwerionenforsch GSI, Darmstadt, Germany. Univ Calif Davis, Davis, CA 95616 USA. Joint Inst Nucl Res, Dubna, Russia. Univ Frankfurt, Fachbereich Phys, D-6000 Frankfurt, Germany. Kent State Univ, Kent, OH 44242 USA. Univ Calif Los Angeles, Los Angeles, CA USA. Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Univ Washington, Nucl Phys Lab, Seattle, WA 98195 USA. Yale Univ, New Haven, CT USA. Rudjer Boskovic Inst, Zagreb, Croatia. RP Appelshauser, H (reprint author), Univ Heidelberg, Inst Phys, Philosophenweg 12, D-6900 Heidelberg, Germany. RI Barnby, Lee/G-2135-2010; Voloshin, Sergei/I-4122-2013; Levai, Peter/A-1544-2014; Carr, Lincoln/E-3819-2016; OI Barnby, Lee/0000-0001-7357-9904; Carr, Lincoln/0000-0002-4848-7941; Cristinziani, Markus/0000-0003-3893-9171 NR 30 TC 159 Z9 162 U1 0 U2 4 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 JUL 29 PY 1999 VL 459 IS 4 BP 679 EP 686 DI 10.1016/S0370-2693(99)00673-5 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 224PP UT WOS:000081907700039 ER PT J AU Krstic, PS Schultz, DR AF Krstic, PS Schultz, DR TI Elastic scattering and charge transfer in slow collisions: isotopes of H and H+ colliding with isotopes of H and with He SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID PROTON COLLISIONS; ATOMIC-HYDROGEN; CROSS-SECTIONS; LOW ENERGIES; EXCHANGE AB Differential and integral cross sections are calculated in the centre of mass energy range 0.1-100 eV for elastic scattering of protons (H+, D+, T+) by helium and of symmetric combinations of protons (H+, D+, T+) and hydrogen atoms (H, D, T) by hydrogen atoms (H, D, T). In addition, we derive from the elastic differential cross sections the momentum transfer and viscosity cross sections of use in the study of plasma transport, and compute the charge transfer cross section. Fully quantal and semiclassical approaches are utilized in these calculations, as are very accurate electronic potential energy curves. The results are compared with available data. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Krstic, PS (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 32 TC 59 Z9 59 U1 2 U2 11 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUL 28 PY 1999 VL 32 IS 14 BP 3485 EP 3509 DI 10.1088/0953-4075/32/14/317 PG 25 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 225DE UT WOS:000081941500027 ER PT J AU Borisov, AB Cameron, S Dai, Y Davis, J Nelson, T Schroeder, WA Longworth, JW Boyer, K Rhodes, CK AF Borisov, AB Cameron, S Dai, Y Davis, J Nelson, T Schroeder, WA Longworth, JW Boyer, K Rhodes, CK TI Dynamics of optimized stable channel formation of intense laser pulses with the relativistic/charge-displacement mechanism SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID X-RAY AMPLIFICATION; UNDERDENSE PLASMA; ULTRAVIOLET PULSES; PREFORMED PLASMA; PROPAGATION; ULTRASHORT; EXCITATION; SIMULATION; GENERATION; WAKEFIELD AB Studies of the dynamics of stable relativistic/ponderomotive channel formation demonstrate that the use of an appropriate longitudinal gradient in the electron density can significantly enhance the efficiency of the power compression. A unidirectional stable zone locking rule, which allows the operating point of the system to enter the region of stable channelled propagation, but blocks departures from it, is established. These characteristics are extremely favourable for kilovolt x-ray amplification, charged-particle acceleration and the initiation of nuclear reactions. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Univ Tsukuba, Ctr Tsukuba Adv Res Alliance, Tsukuba, Ibaraki 305, Japan. Sandia Natl Labs, Albuquerque, NM 87185 USA. Tokyo Inst Technol, Dept Math & Comp Sci, Meguro Ku, Tokyo 1528552, Japan. USN, Res Lab, Washington, DC 20375 USA. IIT, Dept Phys, Chicago, IL 60616 USA. RP Borisov, AB (reprint author), Univ Illinois, Dept Phys, 845 W Taylor St,MC 273, Chicago, IL 60607 USA. NR 33 TC 15 Z9 15 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUL 28 PY 1999 VL 32 IS 14 BP 3511 EP 3525 DI 10.1088/0953-4075/32/14/318 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 225DE UT WOS:000081941500028 ER PT J AU Shao, XM Carlos, RC Kirkland, MW Kao, CYJ Jacobson, AR AF Shao, XM Carlos, RC Kirkland, MW Kao, CYJ Jacobson, AR TI Observations of precipitable water vapor fluctuations in convective boundary layer via microwave interferometry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC PHASE FLUCTUATIONS; SIMPLE BIOSPHERE MODEL; ANTENNA SPACINGS; REFRACTIVE-INDEX; GHZ AB At microwave frequencies, each centimeter of precipitable water vapor (PWV) causes about 6.45 cm of extra electrical path length relative to the "dry" air. The fluctuations of the water vapor dominate the changes of the effective path length through the atmosphere in a relatively short time period of a few hours. In this paper we describe a microwave interferometer developed for water vapor investigations and present the observation results. The interferometer consists of 10 antennas along two orthogonal 400-m arms that form many baselines (antenna pairs) ranging from 100 to 400 m. All the antennas receive a common CW signal (11.7 GHz) from a geostationary television satellite, and phase differences between pairs of antennas are measured. The phase differences reflect the column-integrated water vapor differences from the top of the atmosphere to the spatially separated antennas at the ground. The interferometric, baseline-differential measurements allow us to study the statistical properties of the PWV fluctuations, as well as the turbulent activity of the convective boundary layer (CBL). Structure function analysis of the interferometer measurements shows good agreement with results obtained from the Very Large Array (VLA) and with a theoretical model developed for radio astronomical very long baseline interferometry (VLBI), reported previously by other investigators. The diurnally varying structure constant correlates remarkably well with the combination of the latent and sensible heat fluxes measured simultaneously from a 10-m meteorological tower. The average drift velocity of the PWV over the interferometer was also derived from the measurements. The derived velocity agrees well during the morning hours with the wind measured by an anemometer at the center of the interferometer. C1 Los Alamos Natl Lab, Space & Atmospher Sci Gr, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Atmospher & Climate Sci Grp, Los Alamos, NM 87545 USA. RP Shao, XM (reprint author), Los Alamos Natl Lab, Space & Atmospher Sci Gr, NIS 1,MS D 466, Los Alamos, NM 87545 USA. EM xshao@lanl.gov OI Kirkland, Matt/0000-0002-1217-8864 NR 26 TC 1 Z9 1 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1999 VL 104 IS D14 BP 16729 EP 16740 DI 10.1029/1999JD900263 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220ET UT WOS:000081652100008 ER PT J AU Chiu, HJ Chen, HL Lin, TL Lin, JS AF Chiu, HJ Chen, HL Lin, TL Lin, JS TI Phase structure of poly(3-hydroxy butyrate)/poly(vinyl acetate) blends probed by small-angle X-ray scattering SO MACROMOLECULES LA English DT Article ID POLY(ETHYLENE OXIDE) BLENDS; SEMICRYSTALLINE POLYMER BLENDS; CRYSTALLIZATION BEHAVIOR; THERMAL-BEHAVIOR; MORPHOLOGY; POLY(EPSILON-CAPROLACTONE); MISCIBILITY; POLYETHYLENE; MELT AB The semicrystalline morphology of poly(3-hydroxy butyrate) (PHB)/poly(vinyl acetate) (PVAc) blends at four crystallization temperatures (T-c = 70, 90, 110, and 125 degrees C) was probed by small-angle X-ray scattering (SAXS). Morphological parameters including the crystal thickness (l(c)) and the amorphous layer thickness (l(a)) were deduced from the interphase distribution function. Blending with PVAc thickened the PHB crystals. The amorphous layers were also swollen upon blending, but l(a) displayed a maximum in its variation with PVAc composition. A zero-angle scattering was observed in the Lorentz-corrected SAXS profiles of PHB/PVAc 60/40 blend crystallized at 110 and 125 degrees C and 50/50 composition crystallized at 90-125 degrees C. Such a zero-angle scattering was attributed to the presences of amorphous domains between the lamellar stacks so as to generate gaps in the sequential stacking of lamellae. These amorphous domains were generated by the interfibrillar segregation of PVAc, where PVAc was expelled beyond several layers of lamellae and subsequently resided in the regions between the lamellar stacks. On the basis of the composition variation of l(a), the observation of zero-angle scattering, and the magnitude of the volume fraction of lamellar stacks, it was concluded that when PVAc composition was less than or equal to 20 wt %, the morphology was predominantly characterized by the interlamellar segregation; above this composition, interlamellar and interfibrillar segregation coexisted, and the extent of interfibrillar segregation increased with the increases of PVAc composition and crystallization temperature. C1 Natl Tsing Hua Univ, Dept Chem Engn, Hsinchu 30013, Taiwan. Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 30013, Taiwan. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Chen, HL (reprint author), Natl Tsing Hua Univ, Dept Chem Engn, Hsinchu 30013, Taiwan. NR 37 TC 50 Z9 50 U1 3 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUL 27 PY 1999 VL 32 IS 15 BP 4969 EP 4974 DI 10.1021/ma990304+ PG 6 WC Polymer Science SC Polymer Science GA 222AE UT WOS:000081759400031 ER PT J AU Micic, OI Ahrenkiel, SP Bertram, D Nozik, AJ AF Micic, OI Ahrenkiel, SP Bertram, D Nozik, AJ TI Synthesis, structure, and optical properties of colloidal GaN quantum dots SO APPLIED PHYSICS LETTERS LA English DT Article ID NANOCRYSTALLINE GALLIUM NITRIDE; INP; CYCLOTRIGALLAZANE; CONVERSION; PRECURSOR; SOLIDS; ROUTE AB Colloidal chemistry was used to synthesize GaN quantum dots. A GaN precursor, polymeric gallium imide, {Ga(NH)(3/2)}(n), which was prepared by the reaction of dimeric amidogallium with ammonia at room temperature, was heated in trioctylamine at 360 degrees C for one day to produce GaN nanocrystals. The GaN particles were separated, purified, and partially dispersed in a nonpolar solvent to yield transparent colloidal solutions that consisted of individual GaN particles. The GaN nanocrystals have a spherical shape and mean diameter of about 30 +/- 12 Angstrom. The spectroscopic behavior of colloidal transparent dispersion has been investigated and shows that the band gap of the GaN nanocrystals shifts to slightly higher energy due to quantum confinement. The photoluminescence spectrum at 10 K (excited at 310 nm) shows band edge emission with several emission peaks in the range between 3.2 and 3.8 eV, while the photoluminescence excitation spectrum shows two excited-state transitions at higher energies. (C) 1999 American Institute of Physics. [S0003-6951(99)04230-8]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Micic, OI (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Nozik, Arthur/A-1481-2012; Nozik, Arthur/P-2641-2016 NR 22 TC 120 Z9 121 U1 2 U2 34 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 26 PY 1999 VL 75 IS 4 BP 478 EP 480 PG 3 WC Physics, Applied SC Physics GA 218UK UT WOS:000081570400014 ER PT J AU Yue, GZ Lorentzen, JD Lin, J Han, DX Wang, Q AF Yue, GZ Lorentzen, JD Lin, J Han, DX Wang, Q TI Photoluminescence and Raman studies in thin-film materials: Transition from amorphous to microcrystalline silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID HYDROGEN DILUTION; POLYCRYSTALLINE AB We measured photoluminescence (PL) and Raman spectra for films deposited by hot-wire chemical vapor deposition using various hydrogen to silane ratios. We observed: (a) a PL peak energy increase from 1.25 to 1.4 eV as the material approaches the a- to mu c-Si transition region; (b) a dual-PL peak at 1.3 and 1.0 eV for the film with a H dilution ratio of 3; and (c) as the H ratio increases, the 1.3 eV PL fades away and the low energy PL dominates. Meanwhile, a redshift of the peak position, a decrease of the intensity, and a narrower bandwidth for the low energy PL are also observed. The low energy PL is explained by band-tail radiative transitions from two types of grain boundaries. (C) 1999 American Institute of Physics. [S0003-6951(99)02727-8]. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Han, DX (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NR 11 TC 166 Z9 175 U1 2 U2 23 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 26 PY 1999 VL 75 IS 4 BP 492 EP 494 DI 10.1063/1.124426 PG 3 WC Physics, Applied SC Physics GA 218UK UT WOS:000081570400019 ER PT J AU Neimann, K Neumam, R Rabion, A Buchanan, RM Fish, RH AF Neimann, K Neumam, R Rabion, A Buchanan, RM Fish, RH TI Biomimetic oxidation studies. 11. Alkane functionalization in aqueous solution utilizing in situ formed [Fe2O(eta(1)-H2O)(eta(1)-OAc)(TPA)(2)](3+), as an MMO model precatalyst, embedded in surface-derivatized silica and contained in micelles SO INORGANIC CHEMISTRY LA English DT Article ID SPANNING STEROIDAL METALLOPORPHYRINS; MONOOXYGENASE ENZYME MODELS; BUTYL HYDROPEROXIDE; COMPLEXES; VESICLES; CATALYSIS AB The biomimetic, methane monooxygenase enzyme (MMO) precatalyst, [Fe2O(eta(1)-H2O)(eta(1)-OAc)(TPA)(2)](3+) (TPA = tris [(2-pyridyl)methyl]amine), 1, formed in situ at pH 4.2 from [Fe2O(mu-OAc)(TPA)(2)](3+), 2, was embedded in an amorphous silicate surface modified by a combination of hydrophilic poly(ethylene oxide) and hydrophobic poly(propylene oxide). The resulting catalytic assembly was found to be a biomimetic model for the MMO active site within a hydrophobic macroenvironment, allowing alkane functionalization with tert-butyl hydroperoxide (TBHP)/O-2 in an aqueous reaction medium (pH 4.2). For example, cyclohexane was oxidized to a mixture of cyclohexanone, cyclohexanol, and cyclohexyl-tert-butyl peroxide, in a ratio of similar to 3:1:2. The balance between poly (ethylene oxide) and poly(propylene oxide), tethered on the silica surface, was crucial for maximizing the catalytic activity. The silica-based catalytic assembly showed reactivity somewhat higher in comparison to an aqueous micelle system utilizing the surfactant, cetyltrimethylammonium hydrogen sulfate at its critical micelle concentration, in which functionalization of cyclohexane with TBHP/O-2 in the presence of 1 was also studied at pH 4.2 and was found to provide similar products: cyclohexanol, cyclohexanone, and cyclohexyl-tert-butyl peroxide, in a ratio of similar to 2:3:1. Moreover, the mechanism for both the silica-based catalytic assembly and the aqueous micelle system was found to occur via the Haber-Weiss process, in which redox chemistry between 1 and TBHP provides both the t-BuO. and t-BuOO. radicals. The t-BuO. radical initiates the C-H functionalization reaction to form the carbon radical, followed by O-2 trapping, to provide cyclohexyl hydroperoxide, which produces the cyclohexanol and cyclohexanone in the presence of 1, whereas the coupling product emanates from t-BuOO. and cyclohexyl radicals. A discussion concerning both approaches for alkane functionalization in water will be presented. C1 Hebrew Univ Jerusalem, Grad Sch Appl Sci, Casali Inst Appl Chem, IL-91904 Jerusalem, Israel. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. ELF Aquitaine Co, Grp Rech Lacq, F-64170 Artix, France. Univ Louisville, Dept Chem, Louisville, KY 40292 USA. RP Neumam, R (reprint author), Hebrew Univ Jerusalem, Grad Sch Appl Sci, Casali Inst Appl Chem, IL-91904 Jerusalem, Israel. NR 21 TC 29 Z9 29 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JUL 26 PY 1999 VL 38 IS 15 BP 3575 EP 3580 DI 10.1021/ic990155b PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 221FJ UT WOS:000081713200024 ER PT J AU Miller, JR Rowning, BA Larabell, CA Yang-Snyder, JA Bates, RL Moon, RT AF Miller, JR Rowning, BA Larabell, CA Yang-Snyder, JA Bates, RL Moon, RT TI Establishment of the dorsal-ventral axis in Xenopus embryos coincides with the dorsal enrichment of Dishevelled that is dependent on cortical rotation SO JOURNAL OF CELL BIOLOGY LA English DT Article DE Dishevelled; green fluorescent protein; beta-catenin; Xenopus; microtubules ID WNT SIGNALING PATHWAY; BETA-CATENIN; EGGS; SPECIFICATION; EXPRESSION; INDUCTION; WINGLESS; TRANSCRIPTION; LOCALIZATION; CYTOPLASM AB Examination of the subcellular localization of Dishevelled (Dsh) in fertilized Xenopus eggs revealed that Dsh is associated with vesicle-like organelles that are enriched on the prospective dorsal side of the embryo after cortical rotation. Dorsal enrichment of Dsh is blocked by UV irradiation of the vegetal pole, a treatment that inhibits development of dorsal cell fates, linking accumulation of Dsh and specification of dorsal cell fates. Investigation of the dynamics of Dsh localization using Dsh tagged with green fluorescent protein (Dsh-GFP) demonstrated that Dsh-GFP associates with small vesicle-like organelles that are directionally transported along the parallel array of microtubules towards the prospective dorsal side of the embryo during cortical rotation. Perturbing the assembly of the microtubule array with D2O, a treatment that promotes the random assembly of the array and the dorsalization of embryos, randomizes translocation of Dsh-GFP. Conversely, UV irradiation of the vegetal pole abolishes movement of Dsh-GFP. Finally we demonstrate that overexpression of Dsh can stabilize beta-catenin in Xenopns. These data suggest that the directional translocation of Dsh along microtubules during cortical rotation and its subsequent enrichment on the prospective dorsal side of the embryo play a role in locally activating a maternal Wnt pathway responsible for establishing dorsal cell fates in Xenopus. C1 Univ Washington, Dept Pharmacol, Howard Hughes Med Inst, Sch Med, Seattle, WA 98195 USA. Univ Washington, Sch Med, Ctr Dev Biol, Seattle, WA 98195 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Moon, RT (reprint author), Univ Washington, Dept Pharmacol, Howard Hughes Med Inst, Sch Med, Room K536C Hlth Sci Bldg,Campus Box 357750, Seattle, WA 98195 USA. RI Moon, Randall/B-1743-2014 OI Moon, Randall/0000-0002-9352-1408 FU NICHD NIH HHS [HD29360] NR 35 TC 175 Z9 179 U1 1 U2 13 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD JUL 26 PY 1999 VL 146 IS 2 BP 427 EP 437 DI 10.1083/jcb.146.2.427 PG 11 WC Cell Biology SC Cell Biology GA 221KF UT WOS:000081725700014 PM 10427095 ER PT J AU Cardman, LS AF Cardman, LS TI Electron scattering: A microscope for nuclear and nucleon structure SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT International Nuclear Physics Conference (INPC98) CY AUG 24-28, 1998 CL PARIS, FRANCE SP Int Union Pure & Appl Phys ID MAGNETIC FORM-FACTOR; DEUTERON; PHOTODISINTEGRATION; STATE AB We review progress and assess the outlook for investigations of the structure of nuclei and nucleons using electron scattering. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Cardman, LS (reprint author), Thomas Jefferson Natl Accelerator Facil, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 36 TC 2 Z9 2 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 JUL 26 PY 1999 VL 654 IS 1-2 BP 73C EP 95C DI 10.1016/S0375-9474(99)00323-1 PG 23 WC Physics, Nuclear SC Physics GA 236WF UT WOS:000082621700007 ER PT J AU Nazarewicz, W AF Nazarewicz, W TI Nuclear structure SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT International Nuclear Physics Conference (INPC98) CY AUG 24-28, 1998 CL PARIS, FRANCE SP Int Union Pure & Appl Phys ID MODEL MONTE-CARLO; GROUND-STATE PROPERTIES; MEAN-FIELD THEORY; DRIP-LINE NUCLEI; SHELL-MODEL; PSEUDOSPIN SYMMETRY; SUPERHEAVY NUCLEI; NEUTRON DROPS; R-PROCESS; IDENTIFICATION AB Current developments in nuclear structure are discussed from a theoretical perspective. The studies of the nuclear many-body system provide us with invaluable information about the nature of the nuclear interaction, nucleonic correlations at various energy-distance scales, and the modes of the nucleonic matter. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. RP Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 80 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD JUL 26 PY 1999 VL 654 IS 1-2 BP 195C EP 214C DI 10.1016/S0375-9474(99)00254-7 PG 20 WC Physics, Nuclear SC Physics GA 236WF UT WOS:000082621700013 ER PT J AU Blake, C Cook, LL Apel, WA Gostomski, PA AF Blake, C Cook, LL Apel, WA Gostomski, PA TI Biofiltration controls odors from asphalt processing plant SO OIL & GAS JOURNAL LA English DT Article C1 Idaho Natl Engn & Environm Lab, Dept Biotechnol, Idaho Falls, ID USA. Univ Canterbury, Christchurch 1, New Zealand. NR 4 TC 0 Z9 0 U1 0 U2 1 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 USA SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD JUL 26 PY 1999 VL 97 IS 30 BP 69 EP 72 PG 4 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 220FX UT WOS:000081654900020 ER PT J AU Sornborger, A Parry, M AF Sornborger, A Parry, M TI Patterns from preheating SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSITIONS; INFLATION; BARYOGENESIS; DECAY; EQUILIBRIUM; UNIVERSE AB The formation of regular patterns is a well-known phenomenon in condensed matter physics. Systems that exhibit pattern formation,are typically driven and dissipative with pattern formation occurring in the weakly nonlinear regime and sometimes even in more strongly nonlinear regions of parameter space. In the early universe, parametric resonance can drive explosive particle production called preheating. The fields that are populated then decay quantum mechanically if their particles are unstable. Thus, during: preheating, a driven-dissipative system exists. Motivated by the application to cosmology, we present a case study for pattern formation in relativistic nonlinear wave equations. C1 NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. RP Sornborger, A (reprint author), NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 21 TC 8 Z9 8 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 JUL 26 PY 1999 VL 83 IS 4 BP 666 EP 669 DI 10.1103/PhysRevLett.83.666 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300002 ER PT J AU Perlmutter, S Turner, MS White, M AF Perlmutter, S Turner, MS White, M TI Constraining dark energy with type Ia supernovae and large-scale structure SO PHYSICAL REVIEW LETTERS LA English DT Article ID COSMOLOGICAL CONSTANT; MASS FLUCTUATIONS; UNIVERSE; COMPONENT AB Measurements of the distances to type Ia supernovae have produced strong evidence that the expansion of the Universe is accelerating, implying the existence of a nearly uniform component of dark energy with negative pressure, We show that constraints to this mysterious component based upon large-scale structure nicely complement the SN Ia data, and that together they require Omega(X) = rho(X)/rho(crit) is an element of (0.6,0.7) and w = rho(X)/rho(X) < -0.6 (95% C.L.), for the favored hat Universe. Other cosmological data support this conclusion. The simplest explanation, a cosmological constant, is consistent with this, while some of the other possibilities are not. C1 EO Lawrence Berkeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Perlmutter, S (reprint author), EO Lawrence Berkeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. RI Perlmutter, Saul/I-3505-2015; White, Martin/I-3880-2015 OI Perlmutter, Saul/0000-0002-4436-4661; White, Martin/0000-0001-9912-5070 NR 40 TC 338 Z9 343 U1 2 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 26 PY 1999 VL 83 IS 4 BP 670 EP 673 DI 10.1103/PhysRevLett.83.670 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300003 ER PT J AU Munkholm, A Stephenson, GB Eastman, JA Thompson, C Fini, P Speck, JS Auciello, O Fuoss, PH DenBaars, SP AF Munkholm, A Stephenson, GB Eastman, JA Thompson, C Fini, P Speck, JS Auciello, O Fuoss, PH DenBaars, SP TI Surface structure of GaN(0001) in the chemical vapor deposition environment SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAY-SCATTERING ANALYSIS; X-RAY; 0001 SURFACES; PHASE EPITAXY; GAN; GROWTH; RECONSTRUCTIONS; STOICHIOMETRY AB We report the first observation of the atomic-scale structure of the GaN(0001) surface in the metalorganic chemical vapor deposition environment. Measurements were performed using in situ grazing-incidence x-ray scattering. We determined the surface equilibrium phase diagram as a function of temperature and ammonia partial pressure, which contains two phases with 1 X 1 and (root 3 X 2 root 3)R30 degrees symmetries. The (root 5 X 2 root 5)R30 degrees phase is found to have a novel "missing row" structure with 1/3 of the surface Ga atoms absent. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. AT&T Labs Res, Florham Park, NJ 07932 USA. RP Munkholm, A (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Eastman, Jeffrey/E-4380-2011; Speck, James/H-5646-2011; OI Eastman, Jeff/0000-0002-0847-4265; Thompson, Carol/0000-0003-3832-4855 NR 27 TC 37 Z9 37 U1 0 U2 10 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 JUL 26 PY 1999 VL 83 IS 4 BP 741 EP 744 DI 10.1103/PhysRevLett.83.741 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300021 ER PT J AU Ebert, P Zhang, TJ Kluge, F Simon, M Zhang, ZY Urban, K AF Ebert, P Zhang, TJ Kluge, F Simon, M Zhang, ZY Urban, K TI Importance of many-body effects in the clustering of charged Zn dopant atoms in GaAs SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; GAAS(110) SURFACE; ANION VACANCIES; INP(110); IMAGES AB The spatial distribution of negatively charged Zn dopant atoms in GaAs has been investigated by cross-sectional scanning tunneling microscopy. At high densities, the dopant atoms exhibit clear clustering behavior, suggesting the existence of an effective attractive interaction in addition to the screened Coulomb repulsion between two dopants. By analyzing the data through Monte Carlo simulations, we have extracted the intrinsic screening length at different dopant densities and attributed the origin of the effective attraction to strong many-body effects in the dopant-dopant repulsion. C1 Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Ebert, P (reprint author), Forschungszentrum Julich, Inst Festkorperforsch, Postfach 1913, D-52425 Julich, Germany. OI Ebert, Ph./0000-0002-2022-2378 NR 16 TC 37 Z9 37 U1 2 U2 5 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 JUL 26 PY 1999 VL 83 IS 4 BP 757 EP 760 DI 10.1103/PhysRevLett.83.757 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300025 ER PT J AU Ocko, BM Robinson, IK Weinert, M Randler, RJ Kolb, DM AF Ocko, BM Robinson, IK Weinert, M Randler, RJ Kolb, DM TI Thickness induced buckling of bcc copper films SO PHYSICAL REVIEW LETTERS LA English DT Article ID CU; DIFFRACTION; FCC AB Copper films electrodeposited on Au(100) develop a buckling instability after the 11th layer leading to stripes with a 60-75 Angstrom period. Analysis of the x-ray diffraction data shows that the entire copper him restructures by forming regions which are locally orthorhombic in a spatially modulated pattern. This distortion is supported by first-principles calculations. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Ulm, Dept Electrochem, D-89069 Ulm, Germany. RP Ocko, BM (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 17 TC 16 Z9 17 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 JUL 26 PY 1999 VL 83 IS 4 BP 780 EP 783 DI 10.1103/PhysRevLett.83.780 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300031 ER PT J AU Mesot, J Norman, MR Ding, H Randeria, M Campuzano, JC Paramekanti, A Fretwell, HM Kaminski, A Takeuchi, T Yokoya, T Sato, T Takahashi, T Mochiku, T Kadowaki, K AF Mesot, J Norman, MR Ding, H Randeria, M Campuzano, JC Paramekanti, A Fretwell, HM Kaminski, A Takeuchi, T Yokoya, T Sato, T Takahashi, T Mochiku, T Kadowaki, K TI Superconducting gap anisotropy and quasiparticle interactions: A doping dependent photoemission study SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-C SUPERCONDUCTORS; A-B PLANE; FERMI-SURFACE; PENETRATION DEPTH; ELECTRONIC-STRUCTURE; BI2SR2CACU2O8+DELTA; TEMPERATURE; STATE; IMPEDANCE; PSEUDOGAP AB Comparing photoemission measurements on Bi2212 with penetration depth data, we show that a description of the nodal excitations of the d-wave superconducting state in terms of noninteracting quasiparticles is inadequate, and we estimate the magnitude and doping dependence of the Landau interaction parameter which renormalizes the linear T contribution to the superfluid density. Furthermore, although consistent with d-wave symmetry, the gap with underdoping cannot be fit by the simple cosk(x) - cosk(y) form, which suggests an increasing importance of long range interactions as the insulator is approached. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Tata Inst Fundamental Res, Mumbai 400005, India. Nagoya Univ, Dept Crystalline Mat Sci, Nagoya, Aichi 46401, Japan. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan. Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan. RP Mesot, J (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Takahashi, Takashi/E-5080-2010; Sato, Takafumi/E-5094-2010; Tohoku, Arpes/A-4890-2010; Norman, Michael/C-3644-2013; YOKOYA, Takayoshi/B-1478-2011; OI Ding, Hong/0000-0003-4422-9248 NR 29 TC 231 Z9 233 U1 2 U2 15 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 JUL 26 PY 1999 VL 83 IS 4 BP 840 EP 843 DI 10.1103/PhysRevLett.83.840 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300046 ER PT J AU Kim, YJ Aharony, A Birgeneau, RJ Chou, FC Entin-Wohlman, O Erwin, RW Greven, M Harris, AB Kastner, MA Korenblit, IY Lee, YS Shirane, G AF Kim, YJ Aharony, A Birgeneau, RJ Chou, FC Entin-Wohlman, O Erwin, RW Greven, M Harris, AB Kastner, MA Korenblit, IY Lee, YS Shirane, G TI Ordering due to quantum fluctuations in Sr2Cu3O4Cl2 SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE HEISENBERG-ANTIFERROMAGNET; SPIN; SCATTERING; DISORDER AB Sr2Cu3O4Cl2 has Cu-I and Cu-II subsystems, forming interpenetrating S=1/2 square lattice Heisenberg antiferromagnets. The classical ground state is degenerate, due to frustration of the intersubsystem interactions. Magnetic neutron scattering experiments show that quantum fluctuations cause a two dimensional Ising ordering of the Cu-II's, lifting the degeneracy, and a dramatic increase of the Cu-I out-of-plane spin-wave gap, unique for order out of disorder. The spin-wave energies are quantitatively predicted by calculations which include quantum fluctuations. C1 MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Penn, Dept Phys, Philadelphia, PA 19104 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kim, YJ (reprint author), MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RI Kim, Young-June /G-7196-2011; ENTIN, ORA/F-1114-2012; harris, A Brooks/C-8640-2013 OI Kim, Young-June /0000-0002-1172-8895; NR 22 TC 54 Z9 54 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 26 PY 1999 VL 83 IS 4 BP 852 EP 855 DI 10.1103/PhysRevLett.83.852 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300049 ER PT J AU Rohlfing, M Louie, SG AF Rohlfing, M Louie, SG TI Excitons and optical spectrum of the Si(111)-(2 x 1) surface SO PHYSICAL REVIEW LETTERS LA English DT Article ID AB-INITIO CALCULATION; ENERGY ELECTRON-DIFFRACTION; PI-BONDED CHAINS; QUASI-PARTICLE; DIFFERENTIAL REFLECTIVITY; SEMICONDUCTOR SURFACES; STATE BAND; ABSORPTION; INSULATORS; SPECTROSCOPY AB We investigate: excitons at the Si(111)-(2 x 1) surface and their optical spectrum from first principles. This is done by solving the Bethe-Salpeter equation for the two-particle Green's function, including the electron-hole interaction. The optical spectrum of the surface is dominated by a surface exciton formed from the pi-bonded surface states. The excitonic binding energy is more than 1 order of magnitude larger than in hulk Si. The two-particle wave function of the exciton slate is strongly localized at the surface and exhibits distinct anisotropy due to the surface reconstruction. C1 Univ Munster, Inst Theoret Phys Festkorperforsch 2, D-48149 Munster, Germany. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Rohlfing, M (reprint author), Univ Munster, Inst Theoret Phys Festkorperforsch 2, Wilhelm Klemm Str 10, D-48149 Munster, Germany. NR 33 TC 161 Z9 160 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 JUL 26 PY 1999 VL 83 IS 4 BP 856 EP 859 DI 10.1103/PhysRevLett.83.856 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300050 ER PT J AU Abbamonte, P Burns, CA Isaacs, ED Platzman, PM Miller, LL Cheong, SW Klein, MV AF Abbamonte, P Burns, CA Isaacs, ED Platzman, PM Miller, LL Cheong, SW Klein, MV TI Resonant inelastic x-ray scattering from valence excitations in insulating copper oxides SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOMENTUM-TRANSFER DEPENDENCE; CHARGE-TRANSFER EXCITATIONS; RAMAN-SCATTERING; LI; TRANSITION; SR2CUO2CL2; PROBE; EDGE AB We report resonant inelastic x-ray measurements of insulating La2CuO4 and Sr2CuO2Cl2 taken with the incident energy tuned near the Cu K absorption edge. We show that the spectra are well described in a shakeup picture in third-order perturbation theory which exhibits both incoming and outgoing resonances and demonstrate how to extract a spectral function from the raw data. We conclude by showing q-dependent measurements of the charge transfer gap. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Abbamonte, P (reprint author), Solid State Phys Lab, Nijenborgh 4, NL-9747 AG Groningen, Netherlands. NR 19 TC 107 Z9 107 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 JUL 26 PY 1999 VL 83 IS 4 BP 860 EP 863 DI 10.1103/PhysRevLett.83.860 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300051 ER PT J AU Davidson, RC Qin, H Channell, PJ AF Davidson, RC Qin, H Channell, PJ TI Periodically-focused solutions to the nonlinear Vlasov-Maxwell equations for intense charged particle beams SO PHYSICS LETTERS A LA English DT Article ID PROPAGATION AB An intense nonneutral ion beam propagates in the z-direction through a periodic focusing quadrupole field with transverse focusing force, F-toc = -kappa(q)(s)(x (e) over cap(x) - y (e) over cap(y)), on the beam ions. Here, the oscillatory lattice coefficient satisfies kappa(q)(s + s) = kappa(q)(s), where S = const. is the axial periodicity length. The model employs the Vlasov-Maxwell equations to describe the nonlinear evolution of the distribution function f(b)(x, y, x', y',s) and the normalized self-field potential psi(x, y, s) in the transverse laboratory-frame phase space (x, y, x', y'). Using a third-order Hamiltonian averaging technique, a canonical transformation is employed with an expanded generating function which transforms away the rapidly oscillating terms, and leads to a Hamiltonian in the 'slow' transformed variables ((X) over tilde,(Y) over tilde,(X) over tilde',(Y) over tilde') with constant focusing coefficient kappa(fq) = const. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Davidson, RC (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 14 TC 6 Z9 6 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 JUL 26 PY 1999 VL 258 IS 4-6 BP 297 EP 304 DI 10.1016/S0375-9601(99)00388-6 PG 8 WC Physics, Multidisciplinary SC Physics GA 225NW UT WOS:000081968500016 ER PT J AU Androsch, R Wunderlich, B AF Androsch, R Wunderlich, B TI Temperature-modulated DSC using higher harmonics of the Fourier transform SO THERMOCHIMICA ACTA LA English DT Article DE heat capacity; temperature-modulated differential scanning calorimetry; TMDSC; Fourier transformation; higher harmonics ID DIFFERENTIAL SCANNING CALORIMETRY; HEAT-CAPACITY AB In this paper, experiments with temperature-modulated calorimetry are described in which use is made of multiple modulation frequencies for the evaluation of the heat capacity. The different harmonics of the Fourier series of the heat-flow rate and heating rate of a single sawtooth-modulation experiment were deconvoluted to extract data pertaining to different frequencies. In the normally employed temperature-modulated differential scanning calorimetry (TMDSC), one uses only the first harmonic of the Fourier series. In such a typical TMDSC experiment with a period of less than about 150 s, one needs to correct the measurements by extrapolation to zero frequency, utilizing data taken at different frequencies. It is shown that the extrapolation of the heat capacity from the amplitudes of the first and higher harmonics of the Fourier-transforms of heat-flow rate and heating rate permits the evaluation of the correct heat capacity from a single experiment. The number of harmonics which can be used for the correction depends on the chosen period of the sawtooth. In case of the power-compensation calorimeter employed in this study, the upper limit of frequency of the highest harmonic is about 2 pi/10 rad s(-1) (0.1 Hz), i.e., for modulation with a period of 120 s, up to the eleventh harmonic can be utilized, although the amplitude (and precision) decreases for the higher harmonics. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 16 TC 39 Z9 39 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD JUL 26 PY 1999 VL 333 IS 1 BP 27 EP 32 DI 10.1016/S0040-6031(99)00090-8 PG 6 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 223CX UT WOS:000081823500005 ER PT J AU Kliakhandler, IL AF Kliakhandler, IL TI Long interfacial waves in multilayer thin films and coupled Kuramoto-Sivashinsky equations SO JOURNAL OF FLUID MECHANICS LA English DT Article ID LAYERED LIQUID-FILMS; LOW-REYNOLDS-NUMBER; 2 VISCOUS FLUIDS; INCLINED PLANE; INSTABILITY; FLOW; STRATIFICATION; EQUILIBRIUM; SATURATION; STABILITY AB The coupled Kuramoto-Sivashinsky (CKS) equations for multilayer downflowing films are derived and explored. The CKS equations exhibit a wealth of dynamical behaviour, displaying travelling periodic waves, regular and chaotic-like patterns, coexistence of different attractors, and perfect and imperfect synchronization of the interfaces. New physical effects are found, such as suppression of the Rayleigh-Taylor instability for heavy-top stratified films, and new surface-tension-driven instability. C1 Tel Aviv Univ, Sch Math Sci, IL-69978 Tel Aviv, Israel. RP Kliakhandler, IL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Math, Mail Stop 50A-2152,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 35 TC 16 Z9 16 U1 1 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 25 PY 1999 VL 391 BP 45 EP 65 DI 10.1017/S0022112099005297 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 226JJ UT WOS:000082016600003 ER PT J AU Sternlicht, MD Lochter, A Sympson, CJ Huey, B Rougler, JP Gray, JW Pinkel, D Bissell, MJ Werb, Z AF Sternlicht, MD Lochter, A Sympson, CJ Huey, B Rougler, JP Gray, JW Pinkel, D Bissell, MJ Werb, Z TI The stromal proteinase MMP3/stromelysin-1 promotes mammary carcinogenesis SO CELL LA English DT Article ID TRANSGENIC MICE; MATRIX METALLOPROTEINASES; EPITHELIAL-CELLS; GENE-EXPRESSION; BREAST-CANCER; GROWTH-FACTOR; EXTRACELLULAR-MATRIX; JUVENILE POLYPOSIS; TUMOR PROGRESSION; STROMELYSIN-1 AB Matrix metalloproteinases (MMPs) are invariably upregulated in the stromal compartment of epithelial cancers and appear to promote invasion and metastasis. Here we report that phenotypically normal mammary epithelial cells with tetracycline-regulated expression of MMP3/stromelysin-1 (Str1) form epithelial glandular structures in vivo without Str1 but form invasive mesenchymal-like tumors with Str1. Once initiated, the tumors become independent of continued Str1 expression. Str1 also promotes spontaneous premalignant changes and malignant conversion in mammary glands of transgenic mice. These changes are blocked by coexpression of a TIMP1 transgene. The premalignant and malignant lesions have stereotyped genomic changes unlike those seen in other murine mammary cancer models. These data indicate that Str1 influences tumor initiation and alters neoplastic risk. C1 Univ Calif San Francisco, Dept Anat, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Canc Genet Program, San Francisco, CA 94143 USA. RP Sternlicht, MD (reprint author), Univ Calif San Francisco, Dept Anat, San Francisco, CA 94143 USA. FU NCI NIH HHS [R01 CA064786-04A1, CA57621, CA64786, CA72006, P01 CA072006, P01 CA072006-020003, R01 CA057621, R01 CA057621-07, R01 CA064786, R37 CA064786] NR 62 TC 587 Z9 599 U1 1 U2 25 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 0092-8674 J9 CELL JI Cell PD JUL 23 PY 1999 VL 98 IS 2 BP 137 EP 146 DI 10.1016/S0092-8674(00)81009-0 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 219XA UT WOS:000081632300004 PM 10428026 ER PT J AU Thrash, TP Cagle, DW Alford, JM Wright, K Ehrhardt, GJ Mirzadeh, S Wilson, LJ AF Thrash, TP Cagle, DW Alford, JM Wright, K Ehrhardt, GJ Mirzadeh, S Wilson, LJ TI Toward fullerene-based radiopharmaceuticals: high-yield neutron activation of endohedral Ho-165 metallofullerenes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GAMMA-RECOIL; WATER; C-60; ATOMS; TOXICITY; TRACER; MODEL; RATS AB C-60 and endohedral Ho-165 metallofullerenes were irradiated under various neutron flux conditions to maximize the activity of surviving Ho-166 metallofullerenes. C-60 survived irradiation to a fairly high extent (> 80%) at fluences of < 10(18) n cm(-2) (75.8% thermal), but fast-neutron damage (or equivalent oxidative decomposition) progressed rapidly at higher fluences. Under identical conditions the metallofullerenes were degraded more quickly and extensively than was C-60, and decomposition proceeded primarily by fast-neutron damage instead of anticipated (n, gamma)-metal recoil. Irradiation under more thermal neutron flux conditions (96.2% and 99.8%) significantly improved metallofullerene survival (20-30%), and degradation was demonstrated to proceed through the metal-recoil pathway. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Rice Univ, Dept Chem, Houston, TX 77251 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77251 USA. TDA Res, Wheat Ridge, CO 80033 USA. Univ Missouri, Res Reactor Fac, Columbia, MO 65211 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Wilson, LJ (reprint author), Rice Univ, Dept Chem, POB 1892,MS-60, Houston, TX 77251 USA. EM durango@ruf.rice.edu NR 35 TC 48 Z9 48 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUL 23 PY 1999 VL 308 IS 3-4 BP 329 EP 336 DI 10.1016/S0009-2614(99)00581-3 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 219WH UT WOS:000081630600027 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Kinetic study of the mass transfer of S-Troger's base in the system cellulose triacetate and ethanol SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE mass transfer; enantiomer separation; Troger's base; cellulose triacetate ID LIQUID-CHROMATOGRAPHIC SEPARATIONS; CONCENTRATION-DEPENDENCE; LATERAL DIFFUSION; LIGHT-SCATTERING; STATIONARY-PHASE; PORE DIFFUSION; FLOW VELOCITY; 2 ENANTIOMERS; INTERFACE; PACKINGS AB A recent study of the mass transfer kinetics of (-)- or S-Troger's base (TB) between ethanol and microcrystalline cellulose triacetate (CTA) allows an analysis of the concentration dependence of the mass transfer rate coefficient (k(m)). S-TB elutes before R-TB. The retention time of the both compounds decreases with increasing temperature. In this study, experimental data measured between 30 and 50 degrees C were analyzed to provide information on the kinetics of several mass transfer processes which take place in the chromatographic column, i.e., axial and intraparticle dispersion, the fluid-to-particle mass transfer, and the kinetics of adsorption/desorption at the actual adsorption sites. Intraparticle diffusion has the dominant contribution to band broadening at high flow-rates. Both intraparticle diffusivity and the surface diffusion coefficient exhibit a small concentration dependence. The positive dependence of k(m) on the concentration of S-TB seems to result from the properties of the adsorption/desorption kinetics and can be interpreted by considering the phase equilibrium properties. A quantitative analysis of the activation energy of the mass transfer kinetics of S-TB in the CTA column was also attempted. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, 611 Buehler Hall, Knoxville, TN 37996 USA. NR 41 TC 18 Z9 19 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD JUL 23 PY 1999 VL 849 IS 2 BP 445 EP 465 DI 10.1016/S0021-9673(99)00590-7 PG 21 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 220LX UT WOS:000081668400015 PM 10457442 ER PT J AU Feldman, WC Maurice, S Lawrence, DJ Barraclough, BL Elphic, RC Binder, AB AF Feldman, WC Maurice, S Lawrence, DJ Barraclough, BL Elphic, RC Binder, AB TI No ice on the moon? Response SO SCIENCE LA English DT Letter ID LUNAR C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. Lunar Res Inst, Gilroy, CA 95020 USA. RP Feldman, WC (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D-466, Los Alamos, NM 87545 USA. RI Lawrence, David/E-7463-2015 OI Lawrence, David/0000-0002-7696-6667 NR 5 TC 1 Z9 1 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 23 PY 1999 VL 285 IS 5427 BP 531 EP 532 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219LV UT WOS:000081609500016 ER PT J AU Mukai, T Kanahashi, H Yamada, Y Shimojima, K Mabuchi, M Nieh, TG Higashi, K AF Mukai, T Kanahashi, H Yamada, Y Shimojima, K Mabuchi, M Nieh, TG Higashi, K TI Dynamic compressive behavior of an ultra-lightweight magnesium foam SO SCRIPTA MATERIALIA LA English DT Article ID ALUMINUM C1 Osaka Municipal Tech Res Inst, Joto Ku, Osaka 5368553, Japan. Osaka Prefecture Univ, Coll Engn, Dept Met & Mat Sci, Osaka 5998531, Japan. Natl Ind Res Inst Nagoya, Kita Ku, Nagoya, Aichi 4628510, Japan. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Mukai, T (reprint author), Osaka Municipal Tech Res Inst, Joto Ku, 1-6-50 Morinomiya, Osaka 5368553, Japan. RI Nieh, Tai-Gang/G-5912-2011; Mukai, Toshiji/F-9570-2014; Totsukawa, Nobuhisa/D-2028-2017 OI Nieh, Tai-Gang/0000-0002-2814-3746; Mukai, Toshiji/0000-0002-9628-5762; NR 11 TC 57 Z9 65 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD JUL 23 PY 1999 VL 41 IS 4 BP 365 EP 371 DI 10.1016/S1359-6462(99)00186-4 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 223VE UT WOS:000081861600004 ER PT J AU DuPont, JN Robino, CV AF DuPont, JN Robino, CV TI The influence of Nb and C on the solidification microstructures of Fe-Ni-Cr alloys SO SCRIPTA MATERIALIA LA English DT Article DE solidification; phase transformation ID SOLUTE REDISTRIBUTION; DIAGRAM C1 Lehigh Univ, Bethlehem, PA 18015 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP DuPont, JN (reprint author), Lehigh Univ, Bethlehem, PA 18015 USA. NR 12 TC 11 Z9 11 U1 0 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD JUL 23 PY 1999 VL 41 IS 4 BP 449 EP 454 DI 10.1016/S1359-6462(99)00102-5 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 223VE UT WOS:000081861600018 ER PT J AU Berkowitz, J AF Berkowitz, J TI Sum rules and the photoabsorption cross sections of C-60 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRON-IMPACT IONIZATION; GAS-PHASE; VAPOR-PRESSURE; BUCKMINSTERFULLERENE; ABSORPTION; C-70; PHOTOIONIZATION; MOLECULES; ENERGIES; IONS AB The absolute photoabsorption spectrum of C-60 is constructed from experimental data, by linking relative measurements to some recent absolute determinations. Sum rule analysis supports these recent determinations over earlier ones, but substantially better agreement is achieved with similar to 20% reduction in the cross-sections. Attention is focused on the 11-40 eV region, where discrepancies exist in both pseudophotoabsorption and photoionization data. Some inferences are drawn regarding the propensity of large molecules such as C-60 toward multiple ionization, rather than photodissociative ionization. Problems encountered with prior application of quasi-equilibrium theory to the dissociative ionization of C-60 are discussed. (C) 1999 American Institute of Physics. [S0021-9606(99)01728-6]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Berkowitz, J (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 53 TC 65 Z9 65 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1999 VL 111 IS 4 BP 1446 EP 1453 DI 10.1063/1.479404 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215QQ UT WOS:000081393600013 ER PT J AU Patra, CN Yethiraj, A Curro, JG AF Patra, CN Yethiraj, A Curro, JG TI The effect of attractions on the structure of fused sphere chains confined between surfaces SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MONTE-CARLO SIMULATION; STOCHASTIC DYNAMICS SIMULATIONS; POLYMER MELTS; SOLID-SURFACES; COMPUTER-SIMULATION; STATIC PROPERTIES; 2 PLATES; WALLS; DENSITY; INTERFACES AB The effect of attractive interactions on the behavior of polymers between surfaces is studied using Monte Carlo simulations. The molecules are modeled as fused sphere freely rotating chains with fixed bond lengths and bond angles; wall-fluid and fluid-fluid site-site interaction potentials are of the hard sphere plus Yukawa form. For athermal chains the density at the surface (relative to the bulk) is depleted at low densities and enhanced at high densities. The introduction of a fluid-fluid attraction causes a reduction of site density at the surface, and an introduction of a wall-fluid attraction causes an enhancement of site density at the surface, compared to when these interactions are absent. When the wall-fluid and fluid-fluid attractions are of comparable strength, however, the depletion mechanism due to the fluid-fluid attraction dominates. The center of mass profiles show the same trends as the site density profiles. Near the surface, the parallel and the perpendicular components of chain dimensions are different, which is explained in terms of a reorientation of chains. (C) 1999 American Institute of Physics. [S0021-9606(99)70128-5]. C1 Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. RP Patra, CN (reprint author), Univ Wisconsin, Dept Chem, 1101 Univ Ave, Madison, WI 53706 USA. OI Yethiraj, Arun/0000-0002-8579-449X NR 39 TC 23 Z9 23 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1999 VL 111 IS 4 BP 1608 EP 1614 DI 10.1063/1.479421 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215QQ UT WOS:000081393600033 ER PT J AU Annis, BK Lohse, DJ Trouw, F AF Annis, BK Lohse, DJ Trouw, F TI Observation of boson peaks by inelastic neutron scattering in polyolefins SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LOW-ENERGY EXCITATIONS; FRAGILE GLASS FORMERS; AMORPHOUS POLYSTYRENE; RAMAN-SCATTERING; FAST RELAXATION; T-G; POLYMERS; TRANSITION; DYNAMICS; POLYISOBUTYLENE AB Inelastic neutron scattering was used to probe the nature of the boson peak in atactic polypropylene (aPP), head-to-head polypropylene (hhPP), polyisobutylene (PIB) and a 1/1 mass ratio hhPP/PIB blend. Atactic polypropylene is among the most "fragile" of glass formers and was found to have a shoulder rather than the distinctive peak exhibited by the other three polymers. This difference is already apparent at 15 K where relaxations are not expected to occur. The results suggest that the fragility of hhPP is intermediate between aPP and PIB. Within this group of polymers which have similar chemical structures the position of the boson peak appears to correlate with the glass transition temperature and the cohesive energy density. The possibility of a correlation with chain stiffness as expressed by the characteristic ratio is also discussed. (C) 1999 American Institute of Physics. [S0021-9606(99)50128-1]. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Exxon Res & Engn Co, Corp Res Labs, Annandale, NJ 08801 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Annis, BK (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 29 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1999 VL 111 IS 4 BP 1699 EP 1704 DI 10.1063/1.479429 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215QQ UT WOS:000081393600042 ER PT J AU Sun, X Miller, WH AF Sun, X Miller, WH TI Forward-backward initial value representation for semiclassical time correlation functions (vol 110, 6635, 1999) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Sun, X (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Sun, Sean/C-6755-2009 OI Sun, Sean/0000-0002-9077-7088 NR 1 TC 10 Z9 10 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1999 VL 111 IS 4 BP 1788 EP 1788 DI 10.1063/1.479444 PG 1 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215QQ UT WOS:000081393600057 ER PT J AU Hamada, T Brunschwig, BS Eifuku, K Fujita, E Korner, M Sakaki, S van Eldik, R Wishart, JF AF Hamada, T Brunschwig, BS Eifuku, K Fujita, E Korner, M Sakaki, S van Eldik, R Wishart, JF TI Enantioselectivities in electron-transfer and excited state quenching reactions of a chiral ruthenium complex possessing a helical structure SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CYCLIC STAIRCASE VOLTAMMETRY; REDOX REACTION VOLUMES; TB(2,6-PYRIDINEDICARBOXYLATE)3(3-) LUMINESCENCE; ENERGY-TRANSFER; RESOLVED RU(1,10-PHENANTHROLINE)3(2+); ENTHALPIC CONTRIBUTIONS; POLYPYRIDINE COMPLEXES; COBALT(III) COMPLEXES; SOLVENT DEPENDENCE; AQUEOUS-SOLUTION AB The outer-sphere electron-transfer reactions between diastereomers of Ru(menbpy)3(.+) (menbpy = 4,4'-di {(1R,2S,5R)-(-)-menthoxycarbonyl}2,2'-bipyridine) and enantiomers of Co(acac)(3) and Co(edta)(-) have been studied by pulse radiolysis. Delta-Ru(menbpy)3(.+) rapidly reduces Co(acac)(3) in 85% EtOH/H2O (1 mM NaH2PO4) with second-order rate constants of (2.1 +/- 0.1) x 10(7) and (7.8 +/- 0.2) x 10(6) M-1 s(-1) for the Delta- and Lambda-Co(acac)(3) enantiomers, respectively, and an enantioselectivity factor (k(et)(Delta)/k(et)(Lambda)) of 2.7. Lambda-Ru(menbpy)(3)(.+) preferentially reduces Lambda-Co(acac)(3) with an enantioselectivity factor (k(et)(Delta)/k(et)(Lambda)) of 0.8. Activation volume data (Delta V double dagger) suggest that the association between the Delta-Delta isomers in the encounter complex allows' closer interaction of the metal centers than between the other isomer combinations. The value of k(et)(Delta)/k(et)(Lambda) for the reaction of Delta- and Lambda-Co(edta)(-) with Delta-Ru(menbpy)(3)(.+) is 1.2. Electron-transfer reactions of seven racemic Ru(L)(3)(.+) (L substituted phenanthroline) complexes with Co(acac)(3) were also studied and gave rate constants of approximate to 1.5 x 10(9) M-1 s(-1). The quenching of photoexcited *Ru(menbpy)(3)(2+) by Co(acac)(3) and Co(edta)(-) exhibits small stereoselectivity: For Co(acac)(3) in 95 and 85% EtOH/H2O the enantioselectivity factor is 1.2 and 1.1, respectively, barely outside the experimental error. For all other cases the selectivity was unity within the experimental error of the measurement. The quenching rate constants were approximate to 1 x 10(8) and 1.1 x 10(9) M-1 s(-1) for Co(acac)(3) and Co(edta)(-), respectively. Quenching reactions of seven racemic ruthenium(II) phenanthroline complexes with Co(acac)(3) were also studied and found to be faster than those of Ru(menbpy)(3)(2+) by only a factor of approximate to 3 despite an increase in the driving force of approximate to 0.5 eV for electron-transfer quenching. The quenching of *Ru(menbpy)(3)(2+) by Co(acac)(3) is dominated by an energy-transfer mechanism. This conclusion is supported by the magnitude of the quenching rate constants compared with the rate constants for reduction by Ru(menbpy)(3)(.+), the effect of driving-force changes on the quenching rate constant, the low quantum yield of Co(LT) products observed in the CW photolysis, and the lack of long-lived products observed in the flash photolysis experiments. The factors responsible for the selectivity exhibited in the CW photolysis studies of Ru(menbpy)(3)(2+) with Co(acac)(3) are discussed. C1 Kumamoto Univ, Fac Engn, Dept Appl Chem & Biochem, Kumamoto 8608555, Japan. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Erlangen Nurnberg, Inst Inorgan Chem, D-91058 Erlangen, Germany. RP Hamada, T (reprint author), Kumamoto Univ, Fac Engn, Dept Appl Chem & Biochem, Kumamoto 8608555, Japan. RI Brunschwig, Bruce/G-4249-2011; Fujita, Etsuko/D-8814-2013; Wishart, James/L-6303-2013 OI Wishart, James/0000-0002-0488-7636 NR 60 TC 16 Z9 16 U1 1 U2 8 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 JUL 22 PY 1999 VL 103 IS 29 BP 5645 EP 5654 DI 10.1021/jp991116o PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 222CN UT WOS:000081766000004 ER PT J AU Fockenberg, C Hall, GE Preses, JM Sears, TJ Muckerman, JT AF Fockenberg, C Hall, GE Preses, JM Sears, TJ Muckerman, JT TI Kinetics and product study of the reaction of CH3 radicals with O(P-3) atoms using time resolved time-of-flight spectrometry SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABSORPTION CROSS-SECTIONS; 193 NM; STATE DISTRIBUTIONS; LASER PHOTOLYSIS; METHYL RADICALS; ACETONE; CO; SPECTROSCOPY; IONIZATION; PHOTOFRAGMENTATION AB The kinetics and product distribution for the reaction of methyl radicals, CH3, with ground-state O(P-3) oxygen atoms have been investigated. This reaction was studied with a newly constructed apparatus combining a tubular flow reactor and a time-of-flight mass spectrometer (TOFMS), using a hollow-cathode lamp for photoionization. The radicals are produced by an excimer laser pulse (lambda = 193 nm) in the cophotolysis of acetone, CH3COCH3, or bromomethane, CH3Br, and sulfur dioxide, SO2, creating a homogeneous distribution of radicals along the axis of the flow reactor. A small fraction of the reaction mixture is sampled through a pinhole in the wall. Subsequent ionization and repeated extraction of ionized molecules into the TOFMS at a high repetition rate (approximate to 20 kHz) allows the simultaneous observation of rapid changes in the concentration of multiple species in the flow reactor. In addition to the dominant product, formaldehyde (CH2O), carbon monoxide (CO) was detected as a product with a yield of 0.17 +/- 0.11. Analysis of the rate of disappearance of methyl radicals and appearance of formaldehyde for different O(P-3) concentrations resulted in an overall rate coefficient for this reaction k = (1.7 +/- 0.3) x 10(-10) cm(3) molecule(-1) s(-1) at T = (299 +/- 2) K and P = 1 Torr (He). C1 Brookhaven Natl Lab, Chem Dept 555A, Upton, NY 11973 USA. RP Fockenberg, C (reprint author), Brookhaven Natl Lab, Chem Dept 555A, POB 5000, Upton, NY 11973 USA. RI Muckerman, James/D-8752-2013; Sears, Trevor/B-5990-2013; Hall, Gregory/D-4883-2013 OI Sears, Trevor/0000-0002-5559-0154; Hall, Gregory/0000-0002-8534-9783 NR 46 TC 38 Z9 38 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 22 PY 1999 VL 103 IS 29 BP 5722 EP 5731 DI 10.1021/jp991157k PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 222CN UT WOS:000081766000015 ER PT J AU Korber, BT Sharp, PM Ho, DD AF Korber, BT Sharp, PM Ho, DD TI Dating the origin of HIV-I subtypes - reply SO NATURE LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Nottingham, Queens Med Ctr, Dept Genet, Nottingham NG7 2UH, England. Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. RP Korber, BT (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Sharp, Paul/F-5783-2010 OI Sharp, Paul/0000-0001-9771-543X NR 2 TC 4 Z9 4 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 22 PY 1999 VL 400 IS 6742 BP 326 EP 326 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219CH UT WOS:000081590000035 ER PT J AU Lee, CS Janko, B Derenyi, I Barabasi, AL AF Lee, CS Janko, B Derenyi, I Barabasi, AL TI Reducing vortex density in superconductors using the 'ratchet effect' SO NATURE LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; VOLTAGE RECTIFICATION; DYNAMIC PHASES; VORTICES; LATTICES; NOISE; FIELD AB A serious obstacle impeding the application of low- and high-temperature superconductor devices is the presence of trapped magnetic flux(1,2): flux lines or vortices can be induced by fields as small as the Earth's magnetic field Once present, vortices dissipate energy and generate internal noise, limiting the operation of numerous superconducting devices(2,3). Methods used to overcome this difficulty include the pinning of vortices by the incorporation of impurities and defects(4), the construction of flux 'dams'(5), slots and holes(6), and magnetic shields(2,3) which block the penetration of new flux lines in the bulk of the superconductor or reduce the magnetic field in the immediate vicinity of the superconducting device. The most desirable method would be to remove the vortices from the bulk of the superconductor, but there was hitherto no known phenomenon that could form the basis for such a process. Here we show that the application of an alternating current to a superconductor patterned with an asymmetric pinning potential can induce vortex motion whose direction is determined only by the asymmetry of the pattern. The mechanism responsible for this phenomenon is the so-called 'ratchet effect'(7-10), and its working principle applies to both low- and high-temperature superconductors. We demonstrate theoretically that, with an appropriate choice of pinning potential, the ratchet effect can be used to remove vortices from low-temperature superconductors in the parameter range required for various applications. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Chicago, Dept Surg, Chicago, IL 60637 USA. RP Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. EM alb@ndu.edu RI Derenyi, Imre /G-8087-2011 OI Derenyi, Imre /0000-0003-1171-1214 NR 23 TC 202 Z9 202 U1 2 U2 15 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD JUL 22 PY 1999 VL 400 IS 6742 BP 337 EP 340 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219CH UT WOS:000081590000041 ER PT J AU Barber, DC Dyke, A Hillaire-Marcel, C Jennings, AE Andrews, JT Kerwin, MW Bilodeau, G McNeely, R Southon, J Morehead, MD Gagnon, JM AF Barber, DC Dyke, A Hillaire-Marcel, C Jennings, AE Andrews, JT Kerwin, MW Bilodeau, G McNeely, R Southon, J Morehead, MD Gagnon, JM TI Forcing of the cold event of 8,200 years ago by catastrophic drainage of Laurentide lakes SO NATURE LA English DT Article ID HUDSON STRAIT; YOUNGER DRYAS; THERMOHALINE CIRCULATION; FINAL STAGES; ICE-SHEET; YR BP; ATLANTIC; DEGLACIATION; OCEAN; STRATIGRAPHY AB The sensitivity of oceanic thermohaline circulation to freshwater perturbations is a critical issue for understanding abrupt climate change(1). Abrupt climate fluctuations that occurred during both Holocene and Late Pleistocene times have been linked to changes in ocean circulation(2-6) but their causes remain uncertain. One of the largest such events in the Holocene occurred between 8,400 and 8,000 calendar years ago(2,7,8) (7,650-7,200 C-14 years ago), when the temperature dropped by 4-8 degrees C in central Greenland(2) and 1.5-3 degrees C at marine(4,7) and terrestrial(7,8) sites around the northeastern North Atlantic Ocean. The pattern of fooling implies that heat transfer from the ocean to the atmosphere was reduced in the North Atlantic. Here we argue that this cooling event was forced by a massive outflow of fresh water from the Hudson Strait. This conclusion is based on our estimates of the marine C-14 reservoir for Hudson Bay which, in combination with other regional data, indicate that the glacial lakes Agassiz and Ojibway(9-11) (originally dammed by a remnant of the Laurentide ice sheet) drained catastrophically similar to 8,470 calendar years ago; this would have released >10(14) m(3) of fresh water into the Labrador Sea. This finding supports the hypothesis(2,7,8) that a sudden increase in freshwater flux from the waning Laurentide ice sheet reduced sea surface salinity and altered ocean circulation, thereby initiating the most abrupt and widespread cold event to have occurred in the past 10,000 years. C1 Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Geol Survey Canada, Ottawa, ON K1A 0E8, Canada. Univ Quebec, Ctr Rech Geochim Isotop & Geochronol, Montreal, PQ H3C 3P8, Canada. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Canadian Museum Nat, Ottawa, ON K1P 6P4, Canada. RP Barber, DC (reprint author), Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. RI Hillaire-Marcel, Claude/H-1441-2012; Hillaire-Marcel, Claude/C-9153-2013 OI Hillaire-Marcel, Claude/0000-0002-3733-4632 NR 29 TC 645 Z9 661 U1 9 U2 113 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 22 PY 1999 VL 400 IS 6742 BP 344 EP 348 DI 10.1038/22504 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219CH UT WOS:000081590000044 ER PT J AU Matsuta, K Sato, K Fukuda, M Mihara, M Yamaguchi, T Sasaki, M Miyake, T Minamisono, K Tanigaki, M Ohtsubo, T Onishi, T Nojiri, Y Momota, S Fukuda, S Yoshida, K Ozawa, A Kobayashi, T Tanihata, I Alonso, JR Krebs, GF Symons, TJM Kitagawa, H Sagawa, H AF Matsuta, K Sato, K Fukuda, M Mihara, M Yamaguchi, T Sasaki, M Miyake, T Minamisono, K Tanigaki, M Ohtsubo, T Onishi, T Nojiri, Y Momota, S Fukuda, S Yoshida, K Ozawa, A Kobayashi, T Tanihata, I Alonso, JR Krebs, GF Symons, TJM Kitagawa, H Sagawa, H TI Quadrupole moment of the proton drip-line nuclide O-13 SO PHYSICS LETTERS B LA English DT Article ID HALO PROBLEM; B-8; NUCLEI; MODEL; DENSITIES AB The quadrupole moment of the proton drip-line nuclide O-13(I-pi = 3/2(-),T = 3/2,T-1/2 = 8.6 ms) has been determined for the first time by detecting its P-NQR signal following the production of polarized O-13 through the projectile fragmentation process in the O-16 + Be collision. The quadrupole moment has been determined to be /Q(O-13)/ = 11.0 +/- 1.3 mb. The present result together with the quadrupole moment of its mirror partner B-13 is compared with the theoretical values obtained by the shell model code, OXBASH, and by the Hartree-Fock calculation with its single proton separation energy taken into account. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Osaka Univ, Grad Sch Sci, Toyonaka, Osaka 5600043, Japan. RIKEN, Wako, Saitama 35101, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tokyo Metropolitan Univ, Hachioji, Tokyo 19203, Japan. Univ Aizu, Ctr Math Sci, Fukushima 965, Japan. RP Osaka Univ, Grad Sch Sci, Toyonaka, Osaka 5600043, Japan. EM matsuta@hep.sci.osaka-u.ac.jp NR 24 TC 18 Z9 18 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUL 22 PY 1999 VL 459 IS 1-3 BP 81 EP 85 DI 10.1016/S0370-2693(99)00620-6 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500014 ER PT J AU Berger, EL Klasen, M Tait, T AF Berger, EL Klasen, M Tait, T TI Associated production of gauginos and gluinos at hadron colliders in next-to-leading order SUSY-QCD SO PHYSICS LETTERS B LA English DT Article ID SUPERSYMMETRY; COLLISIONS; SQUARK AB We report a next-to-leading order (NLO) calculation of the production of gaugino-like charginos (<(chi)over tilde>(+/-)) and neutralinos (<(chi)over tilde>(0)) in association with gluinos ((g) over tilde) at hadron colliders, including the strong corrections from colored particles and particles. We predict inclusive cross sections at the Fermilab Tevatron and CERN LHC. The NLO cross sections are more stable against variations in the hard-scattering scale parameter and are greater than the LO values. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Michigan State Univ, E Lansing, MI 48824 USA. RP Berger, EL (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUL 22 PY 1999 VL 459 IS 1-3 BP 165 EP 170 DI 10.1016/S0370-2693(99)00617-6 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500027 ER PT J AU Arkani-Hamed, N Grossman, Y AF Arkani-Hamed, N Grossman, Y TI Light active and sterile neutrinos from compositeness SO PHYSICS LETTERS B LA English DT Article ID SOLAR; FERMION; MODELS AB Neutrinos can have naturally small Dirac masses if the Standard Model singlet right-handed neutrinos are light composite fermions. Theories which produce light composite fermions typically generate many of them, three of which can marry the left-handed neutrinos with small Dirac masses. The rest can serve as sterile states which can mix with the Standard Model neutrinos. We present explicit models illustrating this idea. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Arkani-Hamed, N (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 28 TC 35 Z9 35 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 JUL 22 PY 1999 VL 459 IS 1-3 BP 179 EP 182 DI 10.1016/S0370-2693(99)00672-3 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500029 ER PT J AU Hall, L Kolda, C AF Hall, L Kolda, C TI Electroweak symmetry breaking and large extra dimensions SO PHYSICS LETTERS B LA English DT Article ID HIGGS-BOSON PRODUCTION; P(P)OVER-BAR COLLISIONS; MASS; TEV; MILLIMETER; EVENTS; BOUNDS AB If spacetime contains large compact extra dimensions, the fundamental mass scale of nature, ii, may be close to the weak scale, allowing gravitational physics to significantly modify electroweak symmetry breaking. Operators of the form (1/Lambda(2))\phi(dagger)D(mu)phi\(2) and (1/Lambda(2))phi(dagger)W(mu nu)B(mu nu)phi, where W-mu nu and B-mu nu are the SU(2) and U(1) field strengths and phi is the Higgs field, remove the precision electroweak bound on the Higgs boson mass for values of Lambda in a wide range: 4 TeV less than or similar to Lambda less than or similar to 11 TeV. Within this framework, there is no preference between a light Higgs boson, a heavy Higgs boson, or a non-linearly realized SU(2) x U(1) symmetry beneath Lambda. If there is a Higgs doublet, then operators of the form (1/Lambda(2))phi(dagger)phi(G(2),F-2), where G(mu nu) and F-mu nu are the QCD and electromagnetic field strengths, modify the production of the Higgs boson by gluon-gluon fusion, and the decay of the Higgs boson to yy, respectively. At Run II of the Tevatron collider, a yy signal for extra dimensions will be discovered if Lambda is below 2.5 (1) TeV for a Higgs boson of mass 100 (300) GeV, Furthermore, such a signal would point to gravitational physics, rather than to new conventional gauge theories at Lambda. The discovery potential of the LHC depends sensitively on whether the gravitational amplitudes interfere constructively or destructively with the standard model amplitudes, and ranges from Lambda = 3-10 (2-4) TeV for a light (heavy) Higgs boson. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94530 USA. RP Hall, L (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. NR 30 TC 63 Z9 63 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 JUL 22 PY 1999 VL 459 IS 1-3 BP 213 EP 223 DI 10.1016/S0370-2693(99)00618-8 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500035 ER PT J AU Appelquist, T Cohen, A Schmaltz, M Shrock, R AF Appelquist, T Cohen, A Schmaltz, M Shrock, R TI New constraints on chiral gauge theories SO PHYSICS LETTERS B LA English DT Article ID DUALITY AB Recently, a new constraint on the structure of a wide class of strongly coupled field theories has been proposed. It takes the form of an inequality limiting the number of degrees of freedom in the infrared description of a theory to be no larger than the number of underlying, ultraviolet degrees of freedom. Here we apply this inequality to chiral gauge theories. For some models we find that it is always satisfied, while for others we find that the assumption of the validity of the inequality implies a strong additional restriction on the spectrum of massless composite particles. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Yale Univ, Dept Phys, New Haven, CT 06511 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. SUNY Stony Brook, Inst Theoret Phys, Stony Brook, NY 11794 USA. RP Appelquist, T (reprint author), Yale Univ, Dept Phys, New Haven, CT 06511 USA. NR 11 TC 30 Z9 30 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 JUL 22 PY 1999 VL 459 IS 1-3 BP 235 EP 241 DI 10.1016/S0370-2693(99)00616-4 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500037 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SG Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SG Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M CA L3 Collaboration TI Search for R-parity violating chargino and neutralino decays in e(+)e(-) collisions up to root s=183 GeV SO PHYSICS LETTERS B LA English DT Article ID ANGLE BHABHA SCATTERING; LEPTON PAIR PRODUCTION; CARLO EVENT GENERATOR; MONTE-CARLO; SUPERSYMMETRIC PARTICLES; CROSS-SECTIONS; STANDARD MODEL; MUON DETECTOR; L3 EXPERIMENT; Z-PEAK AB A search for chargino and neutralino pair production in e(+)e(-) collisions at center-of-mass energies between 161 GeV and 183 GeV is performed under the assumptions that R-parity is not conserved and that only purely leptonic or hadronic R-parity violating decays are allowed. No signal is found in the data. Limits on the production cross sections, on the Minimal Supersymmetric Standard Model parameters and on the masses of the supersymmetric particles an derived. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sezione Milano, I-20133 Milan, Italy. Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. Lab Annecy Le Vieux Phys Particules, LAPP, IN2P3, CNRS, F-74941 Annecy Le Vieux, France. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sezione Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sezione Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. World Lab, FBLJA Project, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Univ Sci & Technol China, USTC, Hefei 230029, Anhui, Peoples R China. Res Inst High Energy Phys, SEFT, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sezione Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl Lyon, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. ITEP, Moscow, Russia. Ist Nazl Fis Nucl, Sezione Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Catholic Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sezione Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sezione Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Inst Phys Nucl, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, University, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. Natl Tsing Hua Univ, Dept Phys, Hsinchu, Taiwan. RP Ist Nazl Fis Nucl, Sezione Milano, Via Celoria 16, I-20133 Milan, Italy. RI Achard, Pablo/C-2983-2009; Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; Fiandrini, Emanuele/C-4549-2008; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014 OI Diemoz, Marcella/0000-0002-3810-8530; Doria, Alessandra/0000-0002-5381-2649; Faccini, Riccardo/0000-0003-2613-5141; Achard, Pablo/0000-0002-4865-3196; Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Di Lodovico, Francesca/0000-0003-3952-2175; Longo, Egidio/0000-0001-6238-6787; Castellini, Guido/0000-0002-0177-0643; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731 NR 47 TC 12 Z9 12 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUL 22 PY 1999 VL 459 IS 1-3 BP 354 EP 366 DI 10.1016/S0370-2693(99)00680-2 PG 13 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500053 ER PT J AU Krueger, K Allgower, C Kasprzyk, T Spinka, H Underwood, D Yokosawa, A Bunce, G Huang, H Makdisi, Y Roser, T Syphers, M Belikov, NI Derevschikov, AA Matulenko, YA Nogach, LV Nurushev, SB Pavlinov, AI Vasiliev, AN Bai, M Lee, SY Goto, Y Hayashi, N Ichihara, T Okamura, M Saito, N En'yo, H Imai, K Kondo, Y Nakada, Y Nakamura, M Sato, HD Okamura, H Sakai, H Wakasa, T Baturine, V Ogawa, A Ghazikhanian, V Igo, G Trentalange, S Whitten, C AF Krueger, K Allgower, C Kasprzyk, T Spinka, H Underwood, D Yokosawa, A Bunce, G Huang, H Makdisi, Y Roser, T Syphers, M Belikov, NI Derevschikov, AA Matulenko, YA Nogach, LV Nurushev, SB Pavlinov, AI Vasiliev, AN Bai, M Lee, SY Goto, Y Hayashi, N Ichihara, T Okamura, M Saito, N En'yo, H Imai, K Kondo, Y Nakada, Y Nakamura, M Sato, HD Okamura, H Sakai, H Wakasa, T Baturine, V Ogawa, A Ghazikhanian, V Igo, G Trentalange, S Whitten, C TI Large analyzing power in inclusive pi(+/-) production at high x(F) with a 22-GeV/c polarized proton beam SO PHYSICS LETTERS B LA English DT Article ID SINGLE-SPIN ASYMMETRY; 18.5 GEV/C; GEV-C; SCATTERING; QUARKS; PI+ AB The analyzing power, A(N), in inclusive charged-pion production has been measured using a similar to 22-GeV/c transversely polarized proton beam on a carbon target. A large A(N) was found for x(F) > 0.5 and for 0.6 < p(T) < 1.2 GeV/c, with similar magnitudes and opposite sign for pi(+) and pi(-). This mirror behavior and the magnitudes are similar to pi(+/-) production from 200-GeV/c polarized protons on a hydrogen target. The analyzing power for inclusive proton production has also been measured and is consistent with zero. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Inst High Energy Phys, Protvino, Russia. Indiana Univ, Bloomington, IN 47405 USA. RIKEN, Inst Phys & Chem Res, Wako, Saitama 35101, Japan. Kyoto Univ, Dept Phys, Kyoto, Japan. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Penn State Univ, University Pk, PA 16802 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. PNPI, St Petersburg, Russia. Moscow State Univ, Moscow, Russia. RP Krueger, K (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI En'yo, Hideto/B-2440-2015; Sakai, Hideyuki/A-5253-2016 NR 20 TC 72 Z9 72 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 JUL 22 PY 1999 VL 459 IS 1-3 BP 412 EP 416 DI 10.1016/S0370-2693(99)00677-2 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 220VX UT WOS:000081689500057 ER PT J AU Freitag, L Jones, M Plassmann, P AF Freitag, L Jones, M Plassmann, P TI A parallel algorithm for mesh smoothing SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE parallel computing; mesh smoothing; unstructured meshes; parallel algorithms; finite elements ID FINITE-ELEMENT MESHES; LOCAL TRANSFORMATIONS; TRIANGULATIONS; REFINEMENT; GENERATION AB Maintaining good mesh quality during the generation and refinement of unstructured meshes in finite-element applications is an important aspect in obtaining accurate discretizations and well-conditioned linear systems. In this article, we present a mesh-smoothing algorithm based on nonsmooth optimization techniques and a scalable implementation of this algorithm. We prove that the parallel algorithm has a provably fast runtime bound and executes correctly for a parallel random access machine (PRAM) computational model. We extend the PRAM algorithm to distributed memory computers and report results for two- and three-dimensional simplicial meshes that demonstrate the efficiency and scalability of this approach for a number of different test cases. We also examine the effect of different architectures on the parallel algorithm and present results for the IBM SP supercomputer and an ATM-connected network of SPARC Ultras. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Virginia Polytech Inst & State Univ, Bradley Dept Elect & Comp Engn, Blacksburg, VA 24061 USA. Penn State Univ, Dept Comp Sci & Engn, University Pk, PA 16802 USA. RP Freitag, L (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. EM freitag@mcs.anl.gov; mtj@vt.edu; plassman@cse.psu.edu NR 24 TC 21 Z9 22 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD JUL 22 PY 1999 VL 20 IS 6 BP 2023 EP 2040 DI 10.1137/S1064827597323208 PG 18 WC Mathematics, Applied SC Mathematics GA 222XD UT WOS:000081809900006 ER PT J AU Tisseur, F Dongarra, J AF Tisseur, F Dongarra, J TI A parallel divide and conquer algorithm for the symmetric eigenvalue problem on distributed memory architectures SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE divide and conquer; symmetric eigenvalue problem; tridiagonal matrix; rank-one modification; parallel algorithm; ScaLAPACK; LAPACK; distributed memory architecture ID TRIDIAGONAL EIGENPROBLEM; MATRIX; DECOMPOSITION; COMPUTERS AB We present a new parallel implementation of a divide and conquer algorithm for computing the spectral decomposition of a symmetric tridiagonal matrix on distributed memory architectures. The implementation we develop differs from other implementations in that we use a two-dimensional block cyclic distribution of the data, we use the Lowner theorem approach to compute orthogonal eigenvectors, and we introduce permutations before the back transformation of each rank-one update in order to make good use of deflation. This algorithm yields the first scalable, portable, and numerically stable parallel divide and conquer eigensolver. Numerical results confirm the effectiveness of our algorithm. We compare performance of the algorithm with that of the QR algorithm and of bisection followed by inverse iteration on an IBM SP2 and a cluster of Pentium PIIs. C1 Univ Manchester, Dept Math, Manchester M13 9PL, Lancs, England. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Math Sci Sect, Oak Ridge, TN 37831 USA. RP Tisseur, F (reprint author), Univ Manchester, Dept Math, Manchester M13 9PL, Lancs, England. EM ftisseur@ma.man.ac.uk; dongarra@cs.utk.edu RI Tisseur, Francoise/C-7145-2009; Dongarra, Jack/E-3987-2014 NR 31 TC 31 Z9 31 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD JUL 22 PY 1999 VL 20 IS 6 BP 2223 EP 2236 DI 10.1137/S1064827598336951 PG 14 WC Mathematics, Applied SC Mathematics GA 222XD UT WOS:000081809900015 ER PT J AU Cheng, Q Peng, TZ Stevens, RC AF Cheng, Q Peng, TZ Stevens, RC TI Signaling of Escherichia coli enterotoxin on supramolecular redox bilayer vesicles SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SURFACE-PLASMON RESONANCE; LATERAL CHARGE TRANSPORT; ALUMINUM-OXIDE FILMS; CHOLERA-TOXIN; DIFFUSION; ASSEMBLIES; MONOLAYERS; ELECTRODES; MEMBRANES; POLYMERS C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Hangzhou Univ, Dept Chem, Hongzhou 310028, Peoples R China. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Stevens, RC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Cheng, Jason/C-6345-2011; Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 NR 30 TC 21 Z9 22 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 21 PY 1999 VL 121 IS 28 BP 6767 EP 6768 DI 10.1021/ja991234p PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 219HZ UT WOS:000081603000035 ER PT J AU Scoccimarro, R Frieman, JA AF Scoccimarro, R Frieman, JA TI Hyperextended cosmological perturbation theory: Predicting nonlinear clustering amplitudes SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; galaxies : clusters : general; large-scale structure of universe; methods : n-body simulations ID HIGHER-ORDER STATISTICS; LARGE-SCALE STRUCTURE; N-BODY SIMULATIONS; APM GALAXY SURVEY; CORRELATION HIERARCHY; INITIAL CONDITIONS; BBGKY HIERARCHY; DENSITY FIELDS; COSMIC FIELDS; POWER SPECTRA AB We consider the long-standing problem of predicting the hierarchical clustering amplitudes S-p in the strongly nonlinear regime of gravitational evolution. N-body results for the nonlinear evolution of the bispectrum (the Fourier transform of the three-point density correlation function) suggest a physically motivated Ansatz that yields the strongly nonlinear behavior of the skewness, S-3, starting from leading-order perturbation theory. When generalized to higher order (p > 3) polyspectra or correlation functions, this Ansatz leads to a good description of nonlinear amplitudes in the strongly nonlinear regime for both scale-free and cold dark matter models. Furthermore, these results allow us to provide a general fitting formula for the nonlinear evolution of the bispectrum that interpolates between the weakly and strongly nonlinear regimes, analogous to previous expressions for the power spectrum. C1 CITA, McLennan Phys Labs, Toronto, ON M5S 3H8, Canada. Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, NASA, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Scoccimarro, R (reprint author), CITA, McLennan Phys Labs, 60 St George St, Toronto, ON M5S 3H8, Canada. NR 53 TC 82 Z9 84 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1999 VL 520 IS 1 BP 35 EP 44 DI 10.1086/307448 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 215RC UT WOS:000081395500003 ER PT J AU McCutchen-Maloney, SL Giannecchini, CA Hwang, MH Thelen, MP AF McCutchen-Maloney, SL Giannecchini, CA Hwang, MH Thelen, MP TI Domain mapping of the DNA binding, endonuclease, and ERCC1 binding properties of the human DNA repair protein XPF SO BIOCHEMISTRY LA English DT Article ID NUCLEOTIDE-EXCISION-REPAIR; PIGMENTOSUM GROUP-F; SACCHAROMYCES-CEREVISIAE; XERODERMA-PIGMENTOSUM; XPF-ERCC1 COMPLEX; MOLECULAR-CLONING; RAD10 CONSTITUTE; IN-VITRO; RECOMBINATION; GENE AB During nucleotide excision repair, one of the two incisions necessary for removal of a broad spectrum of DNA adducts is made by the human XPF/ERCC1 protein complex. To characterize the biochemical function of XPF, we have expressed and purified the independent 104 kDa recombinant XPF protein from E. coli and determined that it is an endonuclease and can bind DNA in the absence of the ERCC1 subunit. Endonuclease activity was also identified in a stable 70 kDa proteolysis fragment of XPF obtained during protein expression, indicating an N-terminal catalytic domain. Sequence homology and secondary structure predictions indicated a second functional domain at the C-terminus of XPF. To investigate the significance of the two predicted domains, a series of XPF deletion fragments spanning the entire protein were designed and examined for DNA binding, endonuclease activity, and ERCC1 subunit binding. Our results indicate that the N-terminal 378 amino acids of XPF are capable of binding and hydrolyzing DNA, while the C-terminal 214 residues are capable of binding specifically to ERCC1. We propose that the N-terminal domain of XPF contributes to the junction-specific endonuclease activity observed during DNA repair and recombination events. In addition, evidence presented here suggests that the C-terminal domain of XPF is responsible for XPF/ERCC1 complex formation. A working model for the XPF protein is presented illustrating the function of XPF in the nucleotide excision pathway and depicting the two functional domains interacting with DNA and ERCC1. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Livermore, CA 94550 USA. RP Thelen, MP (reprint author), Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, POB 808,L-452, Livermore, CA 94550 USA. RI Thelen, Michael/C-6834-2008; Thelen, Michael/G-2032-2014 OI Thelen, Michael/0000-0002-2479-5480; Thelen, Michael/0000-0002-2479-5480 FU NIGMS NIH HHS [GM18388, GM52120] NR 43 TC 14 Z9 14 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUL 20 PY 1999 VL 38 IS 29 BP 9417 EP 9425 DI 10.1021/bi990591+ PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 219PQ UT WOS:000081616000026 PM 10413517 ER PT J AU Dinneen, MJ Ventura, JA Wilson, MC Zakeri, G AF Dinneen, MJ Ventura, JA Wilson, MC Zakeri, G TI Compound constructions of broadcast networks SO DISCRETE APPLIED MATHEMATICS LA English DT Article DE broadcasting; communication network; minimum broadcast graph; graph compound ID COMMUNICATION-NETWORKS; GRAPHS; BOUNDS AB Compound methods have been shown to be very effective in the construction of broadcast graphs. Compound methods generate a large broadcast graph by combining multiple copies of a broadcast graph G using the structure of another broadcast graph H. Node deletion is also allowed in some of these methods. The subset of connecting nodes of G has been defined as solid h-cover by Bermond, Fraigniaud and Peters, and center node set by Weng and Ventura, This article shows that the two concepts are equivalent. We also provide new properties for center node sets, including bounds on the minimum size of a center node set, show how to reduce the number of center nodes of a broadcast graph generated by a compound method, and propose an iterative compounding algorithm that generates the sparsest known broadcast graphs in many cases. (C) 1999 Elsevier Science B.V. All rights reserved. C1 No Illinois Univ, Dept Math, De Kalb, IL 60115 USA. Univ Auckland, Dept Comp Sci, Auckland, New Zealand. Penn State Univ, Dept Ind & Mfg Engn, University Pk, PA 16802 USA. Argonne Natl Lab, MCS Div, Argonne, IL 60439 USA. RP Dinneen, MJ (reprint author), No Illinois Univ, Dept Math, De Kalb, IL 60115 USA. OI Wilson, Mark/0000-0002-3343-7458 NR 25 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-218X J9 DISCRETE APPL MATH JI Discret Appl. Math. PD JUL 20 PY 1999 VL 93 IS 2-3 BP 205 EP 232 DI 10.1016/S0166-218X(99)00043-8 PG 28 WC Mathematics, Applied SC Mathematics GA 217FQ UT WOS:000081489700006 ER PT J AU Paulini, M AF Paulini, M TI B lifetimes, mixing and CP violation at CDF SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Review ID HEAVY-QUARK PRODUCTION; CTEQ PARTON DISTRIBUTIONS; HADRON-HADRON-COLLISIONS; SILICON VERTEX DETECTOR; PERPENDICULAR-TO JETS; P(P)OVER-BAR COLLISIONS; E+E ANNIHILATION; ROOT-S=1.8 TEV; OSCILLATION FREQUENCY; NARROW RESONANCE AB We review the status of bottom quark physics at the CDF experiment. The measurements reported are based on about 110 pb(-1) of data collected at the Fermilab Tevatron Collider operating at root s = 1.8 TeV. In particular, we review results on B hadron lifetimes, measurements of the time dependence of B-0 (B) over bar(0) oscillations, and a search for CP violation in B-0 --> J/psi K-S(0) decays. Prospects for future B physics at CDF in the next run of the Tevatron Collider, starting in the year 2000, are also presented. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Paulini, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 50B-5239, Berkeley, CA 94720 USA. RI Paulini, Manfred/N-7794-2014 OI Paulini, Manfred/0000-0002-6714-5787 NR 116 TC 15 Z9 15 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUL 20 PY 1999 VL 14 IS 18 BP 2791 EP 2886 DI 10.1142/S0217751X99001391 PG 96 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 222HK UT WOS:000081778500001 ER PT J AU Mowery, MD Kopta, S Ogletree, DF Salmeron, M Evans, CE AF Mowery, MD Kopta, S Ogletree, DF Salmeron, M Evans, CE TI Structural manipulation of the frictional properties of linear polymers in single molecular layers SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; ATOMIC-FORCE MICROSCOPY; SCANNING TUNNELING MICROSCOPY; POLYDIACETYLENE THIN-FILMS; CHAIN-LENGTH DEPENDENCE; SPECTROSCOPIC CHARACTERIZATION; INFRARED-SPECTROSCOPY; THERMAL-STABILITY; ELECTRON-TRANSFER; GOLD AB Manipulation of the frictional properties of self-assembled monolayers containing internal molecular scaffolding through subtle variations in the :,alkyl structure is demonstrated using atomic force microscopy. Photopolymerizable diacetylene groups are incorporated within the alkyl chains of the monolayer, resulting in noncovalent electronic interactions between diacetylene groups, in the unpolymerized form. Under these conditions, discrete transitions in the friction vs load curves are observed, indicating partial collapse of the monolayer at specific loads. Subsequent photopolymerization by UV irradiation results in covalent cross-linking between molecules and-the creation of a linear conjugated polymer backbone. This significantly alters the frictional properties of the monolayers by inhibiting lateral displacement within the monolayer. The presence of domains due to the directionality of the polymer backbone leads to a corresponding directionality in the frictional properties of the assembly that is not observed for the unpolymerized monolayers. C1 Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. RP Mowery, MD (reprint author), Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RI Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 42 TC 34 Z9 35 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 20 PY 1999 VL 15 IS 15 BP 5118 EP 5122 DI 10.1021/la9815998 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 219ZD UT WOS:000081637800028 ER PT J AU Jimenez-Melendo, M Dominguez-Rodriguez, A Routbort, JL AF Jimenez-Melendo, M Dominguez-Rodriguez, A Routbort, JL TI Transient creep of YBa2Cu3O7-x superconductor SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article DE transient creep; YBa2Cu3O7-x; diffusion ID DEPENDENT OXYGEN DIFFUSIVITY; DEFORMATION MAPS; PLASTIC-DEFORMATION; CHEMICAL DIFFUSION; TRACER DIFFUSION; NIO; TEMPERATURE; OXIDES AB Rapid changes of oxygen partial pressure (P-O2) between 10(3) and 2.1 X 10(4) Pa have been carried out during steady-state plastic deformation of polycrystalline YBa2Cu3O7-x (YBCO) at temperatures between 825 and 900 degrees C. Transient creep was observed after such P-O2 changes. The analysis of these creep transients allowed the determination of the chemical diffusion coefficient for reequilibration, which is identical to that found from thermogravimetry and electrical conductivity experiments for oxygen vacancies. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Seville, Dept Fis Mat Condensada, E-41080 Seville, Spain. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Jimenez-Melendo, M (reprint author), Univ Seville, Dept Fis Mat Condensada, Aptdo 1065, E-41080 Seville, Spain. EM melendo@cica.es OI Jimenez Melendo, Manuel/0000-0002-8423-5928; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 35 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 JUL 20 PY 1999 VL 320 IS 3-4 BP 189 EP 196 DI 10.1016/S0921-4534(99)00338-X PG 8 WC Physics, Applied SC Physics GA 228NG UT WOS:000082142100007 ER PT J AU Miltenberger, RJ Mynatt, RL Bruce, BD Wilkison, WO Woychik, RP Michaud, EJ AF Miltenberger, RJ Mynatt, RL Bruce, BD Wilkison, WO Woychik, RP Michaud, EJ TI An agouti mutation lacking the basic domain induces yellow pigmentation but not obesity in transgenic mice SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE pheomelanin; melanocortin receptors ID STIMULATING-HORMONE-RECEPTOR; IN-VIVO; MELANOCORTIN RECEPTORS; FRAMESHIFT MUTATION; ECTOPIC EXPRESSION; PROTEIN; GENE; ANTAGONIST; BINDING; FRAGMENT AB Chronic antagonism of melanocortin receptors by the paracrine-acting agouti gene product induces both yellow fur and a maturity-onset obesity syndrome in mice that ubiquitously express wild-type agouti, Functional analysis of agouti mutations in transgenic mice indicate that the cysteine-rich C terminus, signal peptide, and glycosylation site are required for agouti activity in vivo. In contrast, no biological activity has been ascribed to the conserved basic domain, To examine the functional significance of the agouti basic domain, the entire 29-aa region was deleted from the agouti cDNA, and the resulting mutation (agouti Delta basic) was expressed in transgenic mice under the control of the beta-actin promoter (BAPa Delta basic). Three independent lines of BAPa Delta basic transgenic mice all developed some degree of yellow pigment in the fur, indicating that the agouti Delta basic protein was functional in vivo. However, none of the BAPa Delta basic transgenic mice developed completely yellow fur, obesity, hyperinsulinemia, or hyperglycemia. High levels of agoutii\basic expression in relevant tissues exceeded the level of agouti expression in obese viable yellow mice, suggesting that suboptimal activity or synthesis of the agouti Delta basic protein, rather than insufficient RNA synthesis, accounts for the phenotype of the BAPa Delta basic transgenic mice, These findings implicate a functional role for the agouti basic domain in vivo, possibly influencing the biogenesis of secreted agouti protein or modulating protein-protein interactions that contribute to effective antagonism of melanocortin receptors. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Biochem Cellular & Mol Biol Dept, Knoxville, TN 37996 USA. Glaxo Wellcome Inc, Res Triangle Pk, NC 27709 USA. RP Michaud, EJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 2009,MS 8077, Oak Ridge, TN 37831 USA. NR 41 TC 16 Z9 18 U1 0 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 JUL 20 PY 1999 VL 96 IS 15 BP 8579 EP 8584 DI 10.1073/pnas.96.15.8579 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219CB UT WOS:000081589400055 PM 10411918 ER PT J AU Wofsy, C Vonakis, BM Metzger, H Goldstein, B AF Wofsy, C Vonakis, BM Metzger, H Goldstein, B TI One Lyn molecule is sufficient to initiate phosphorylation of aggregated high-affinity IgE receptors SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID PROTEIN-TYROSINE KINASE; BASOPHILIC LEUKEMIA-CELLS; MEDIATED SIGNAL-TRANSDUCTION; IMMUNOGLOBULIN-E RECEPTOR; EPIDERMAL GROWTH-FACTOR; ACTIVATION MOTIFS; MEMBRANE DOMAINS; ANTIGEN RECEPTOR; LIVING CELLS; SYK AB In response to antigenic stimuli, the multi-subunit immune recognition receptors become aggregated and then phosphorylated on their cytoplasmic tyrosines, For the clonotypic receptors of B and T cells and for Fc receptors such as the high-affinity receptor for IgE (Fc epsilon RI), a Src family kinase initiates this phosphorylation. We ask whether aggregation of the initiating kinase itself is required for signal transduction or whether, alternatively, a single associated kinase molecule can phosphorylate the receptors in an aggregate. We formulate the alternative molecular mechanisms mathematically and compare predictions with experimental findings on Fc epsilon RI-bearing cells expressing varying amounts of the transfected Src family kinase Lyn. The data are consistent with the requirement of only a single Lyn molecule per Fc epsilon RI aggregate to initiate signaling and are inconsistent with a mechanism requiring more than one Lyn molecule. C1 NIAMSD, Arthrit & Rheumatism Branch, NIH, Bethesda, MD 20892 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Div Theoret, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. RP Metzger, H (reprint author), NIAMSD, Arthrit & Rheumatism Branch, NIH, Bethesda, MD 20892 USA. FU NIGMS NIH HHS [GM35556, R37 GM035556, R01 GM035556] NR 42 TC 28 Z9 28 U1 0 U2 0 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 JUL 20 PY 1999 VL 96 IS 15 BP 8615 EP 8620 DI 10.1073/pnas.96.15.8615 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 219CB UT WOS:000081589400061 PM 10411924 ER PT J AU Hansen, CS Calaway, WF Pellin, MJ King, BV Wucher, A AF Hansen, CS Calaway, WF Pellin, MJ King, BV Wucher, A TI Effects of oxygen dosing on Ca cluster yields and energy distributions SO SURFACE SCIENCE LA English DT Article DE alkaline earth metals; clusters ion bombardment; ion-solid interactions; laser methods; secondary ion mass spectrometry; sputtering ID MULTIPHOTON IONIZATION; MOLECULAR-DYNAMICS; LASER-FLUORESCENCE; MASS-SPECTROSCOPY; METAL-CLUSTERS; ATOMS; IONS; PARTICLES; NEUTRALS; TARGETS AB Sputtering from an oxygen-dosed calcium surface under 4 keV Ar+ ion bombardment has been studied. Both the secondary neutral and positive secondary ion fluxes have been analyzed using time-of-flight mass spectrometry to characterize the abundance yields of atoms and molecules. The neutrals were probed using laser post-ionization by an ArF excimer laser. A large number of molecules of the form CamOn (m = 1-5 and n = 0-5) were observed in both the neutral and positive ion channels. Measurements to characterize the sputter yield and abundance distributions of these species were performed at a series of oxygen doses ranging from 0.03 to 300 L. Energy distributions for the secondary neutral species have also been measured as a function of oxygen coverage. The results for neutral atomic calcium agree well with previous measurements. A simple model to describe mono-atomic oxide formation was used to relate oxygen dose to oxygen surface concentration. It was shown that sputter-cleaning the calcium surface could reduce the oxygen surface atom fraction concentration to about 0.01 and that at this level the sputter yield and abundance distribution for Ca clusters was essentially the same as for an oxygen-free calcium surface. The model was extended to larger molecules and found to describe their formation in the Ca-O system quite well. The model offers some insights into the unexpected result that substantial numbers of Ca-2 dimers form during the sputtering process. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Newcastle, Dept Phys, Newcastle, NSW 2308, Australia. Univ Essen Gesamthsch, Dept Phys, D-45117 Essen, Germany. RP Calaway, WF (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 23 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL 20 PY 1999 VL 432 IS 3 BP 199 EP 210 DI 10.1016/S0039-6028(99)00456-2 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 220UK UT WOS:000081685700011 ER PT J AU Xin, Y Rujirawat, S Browning, ND Sporken, R Sivananthan, S Pennycook, SJ Dhar, NK AF Xin, Y Rujirawat, S Browning, ND Sporken, R Sivananthan, S Pennycook, SJ Dhar, NK TI The effect of As passivation on the molecular beam epitaxial growth of high-quality single-domain CdTe(111)B on Si(111) substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID CDTE; SI; HGCDTE AB The effect of As passivation of Si(111) substrates on the subsequent molecular beam epitaxial growth of CdTe(111) is investigated through a detailed comparison of the microstructures of two types of films. The film grown on a substrate treated with a Te flux is found to exhibit a rough film-substrate interface and has very poor crystalline quality with a (111)A orientation. In contrast, a CdTe film grown under identical conditions except for the Si substrate treated with an As flux is observed to have an atomically abrupt film-substrate interface and a single-domain structure in the technologically more relevant (111)B orientation. A growth mechanism for the formation of these high-quality single-domain CdTe(111)B films is proposed. (C) 1999 American Institute of Physics. [S0003-6951(99)03329-X]. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. USA, Res Lab, Adelphi, MD 20783 USA. Fac Univ Notre Dame Paix, Lab LISE, Brussels, Belgium. RP Xin, Y (reprint author), Univ Illinois, Dept Phys, Chicago, IL 60607 USA. OI Browning, Nigel/0000-0003-0491-251X NR 16 TC 28 Z9 28 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 19 PY 1999 VL 75 IS 3 BP 349 EP 351 DI 10.1063/1.124371 PG 3 WC Physics, Applied SC Physics GA 215XP UT WOS:000081409000015 ER PT J AU Ishimaru, M Dickerson, RM Sickafus, KE AF Ishimaru, M Dickerson, RM Sickafus, KE TI High-dose oxygen ion implantation into 6H-SiC SO APPLIED PHYSICS LETTERS LA English DT Article ID SI; SILICON; GAN AB Microstructures of oxygen ion implanted SiC have been examined using transmission electron microscopy (TEM) and scanning transmission electron microscopy equipped with an energy-dispersive x-ray spectrometer. 6H-SiC (0001) substrates were implanted with 180 keV oxygen ions at 650 degrees C to fluences of 0.7x10(18) and 1.4x10(18)/cm(2). A continuous buried oxide layer was formed in both samples, while the surrounding 6H-SiC contained minimal damage. These results suggest that oxygen implantation into SiC is a useful technique to establish SiC-on-insulator structures. In bright-field TEM images, the amorphous layer possessed uniform contrast in the low-dose sample, while it consisted of three distinct layers in the high-dose sample: (1) a bubbled or mottled layer; (2) a dark contrast layer; and (3) a light contrast layer. Chemical measurements revealed that the bubbled and light contrast regions have low silicon and oxygen contents, while carbon enrichment was found in these layers. (C) 1999 American Institute of Physics. [S0003-6951(99)02929-0]. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Kyushu Univ, Dept Mat Sci & Engn, Fukuoka 8128581, Japan. RP Ishimaru, M (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. EM ishimaru@zaiko.kyushu-u.ac.jp NR 14 TC 20 Z9 21 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 19 PY 1999 VL 75 IS 3 BP 352 EP 354 DI 10.1063/1.124372 PG 3 WC Physics, Applied SC Physics GA 215XP UT WOS:000081409000016 ER PT J AU Gao, Y Tran, T Alluri, P AF Gao, Y Tran, T Alluri, P TI Isotopic study of metalorganic chemical vapor deposition of (Ba, Sr)TiO3 films on Pt SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; MECHANISM; GROWTH AB Isotopic labeling experiments (O-18(2)) have been carried out to understand the film-formation reactions in the metalorganic chemical vapor deposition of (Ba, Sr)TiO3 (BST) films. Time-of-flight secondary ion mass spectrometry reveals both M O-18 and M O-16 (M=Ba, Sr, Ti) in the BST films, indicating that the oxygen in the BST films originates from both the gas phase oxidants (O-18), and the precursor ligands (O-16). Use of a 50% O-18(2)-50% N-2 O-16 mixture results in a reduction of O-18 incorporation in the BST film, indicating direct involvement of N2O in the film-formation reactions. Addition of N2O in O-2 also appears to improve film surface morphology and step coverage. (C) 1999 American Institute of Physics. [S0003-6951(99)01029-3]. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Motorola Inc, Mat Technol Labs, Austin, TX 78721 USA. RP Gao, Y (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 19 TC 16 Z9 16 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 19 PY 1999 VL 75 IS 3 BP 415 EP 417 DI 10.1063/1.124393 PG 3 WC Physics, Applied SC Physics GA 215XP UT WOS:000081409000037 ER PT J AU Haas, H Wang, CZ Ho, KM Fahnle, M Elsasser, C AF Haas, H Wang, CZ Ho, KM Fahnle, M Elsasser, C TI Temperature dependence of the phonon frequencies of molybdenum: a tight-binding molecular dynamics study SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID TRANSITION-METALS; INTERATOMIC FORCES; VIBRATIONAL-MODES AB The phonon dispersion curves of molybdenum at zero temperature as well as at elevated temperatures are studied, using our recently developed semi-empirical tight-binding model. At zero temperature the phonon dispersion curves are obtained by frozen-phonon calculations as well as by a dynamical matrix approach. The phonon frequency shifts due to an increase in temperature are calculated by molecular dynamics (MD) simulations and the quasiharmonic contribution to the total frequency shift is determined. An alternative approach for calculating the frequency shifts without performing MD simulations is also presented. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. Max Planck Inst Met Forsch, D-70174 Stuttgart, Germany. RP Haas, H (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 15 TC 9 Z9 9 U1 1 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 19 PY 1999 VL 11 IS 28 BP 5455 EP 5462 DI 10.1088/0953-8984/11/28/306 PG 8 WC Physics, Condensed Matter SC Physics GA 222BU UT WOS:000081764200011 ER PT J AU Moghadam, NY Stocks, GM Ujfalussy, B Shelton, WA Gonis, A Faulkner, JS AF Moghadam, NY Stocks, GM Ujfalussy, B Shelton, WA Gonis, A Faulkner, JS TI Application of the screened Korringa-Kohn-Rostoker method SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID ELECTRONIC-STRUCTURE; STATES AB In the familiar Korringa-Kohn-Rostoker (KKR) or Green function method, wave propagation between scattering sites is described by the so-called structure constants of the lattice (KKR structure constants), where these quantities are treated as having infinite spatial extent. In a recent development, it has been shown that the KKR method can be formulated in terms of screened structure constants that are of finite range (the screened KKR method). Here, we present an alternative formulation of the screened KKR method that is derived from simple manipulations of the multiple-scattering equations. We carry out density-of-states and total-energy calculations for spin-polarized and non-spin-polarized materials using the method. We point out possible unphysical features of the method. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Florida Atlantic Univ, Boca Raton, FL 33431 USA. RP Moghadam, NY (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI Ujfalussy, Balazs/A-8155-2013; Stocks, George Malcollm/Q-1251-2016 OI Ujfalussy, Balazs/0000-0003-3338-4699; Stocks, George Malcollm/0000-0002-9013-260X NR 13 TC 5 Z9 5 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 19 PY 1999 VL 11 IS 28 BP 5505 EP 5515 DI 10.1088/0953-8984/11/28/311 PG 11 WC Physics, Condensed Matter SC Physics GA 222BU UT WOS:000081764200016 ER PT J AU Chen, JW Rupak, G Savage, MJ AF Chen, JW Rupak, G Savage, MJ TI Nucleon-nucleon effective field theory without pions SO NUCLEAR PHYSICS A LA English DT Article ID CHIRAL LAGRANGIANS; NN SCATTERING; RELATIVISTIC CORRECTIONS; DEUTERON SCATTERING; RANGE INTERACTIONS; ISOTOPE SHIFT; REGULARIZATION; FORCES; RENORMALIZATION; POLARIZABILITY AB Nuclear processes involving momenta much below the mass of the pion may be described by an effective field theory in which the pions do not appear as explicit degrees of freedom. The effects of the pion and all other virtual hadrons are reproduced by the coefficients of gauge-invariant local operators involving the nucleon field. Nucleon-nucleon scattering phase shift data constrains many of the coefficients that appear in the effective Lagrangean but at some order in the expansion coefficients enter that must be constrained by other observables. We compute several observables in the two-nucleon sector up to next-to-next-to leading order in the effective field theory without pions, or to the order at which a counterterm involving four-nucleon field operators is encountered. Effective range theory is recovered from the effective field theory up to the order where relativistic corrections enter or where four-nucleon-external current local operators arise. For the deuteron magnetic moment, quadrupole moment and the np --> dy radiative capture cross section a four-nucleon-one-photon counterterm exists at next-to-leading order. The electric polarizability and electric charge form factor of the deuteron are determined up to next-to-next-to-leading order, which includes the first appearance of relativistic corrections. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Chen, JW (reprint author), Univ Washington, Dept Phys, Seattle, WA 98195 USA. OI Chen, Jiunn-Wei/0000-0002-8650-9371 NR 89 TC 165 Z9 165 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 JUL 19 PY 1999 VL 653 IS 4 BP 386 EP 412 DI 10.1016/S0375-9474(99)00298-5 PG 27 WC Physics, Nuclear SC Physics GA 223JV UT WOS:000081838700004 ER PT J AU Jenkins, DG Wadsworth, R Cameron, JA Clark, RM Fossan, DB Hibbert, IM Janzen, VP Krucken, R Lane, GJ Lee, IY Macchiavelli, AO Parry, CM Sears, JM Smith, JF Frauendorf, S AF Jenkins, DG Wadsworth, R Cameron, JA Clark, RM Fossan, DB Hibbert, IM Janzen, VP Krucken, R Lane, GJ Lee, IY Macchiavelli, AO Parry, CM Sears, JM Smith, JF Frauendorf, S TI Confirmation of the shears mechanism in near-spherical tin nuclei SO PHYSICAL REVIEW LETTERS LA English DT Article ID SN-106; BAND AB Lifetimes of states of a magnetic dipole band in each of the nuclei Sn-106,Sn-108 have been obtained using the Doppler shift attenuation method. The deduced B(M1) transition rates show the characteristic behavior associated with the shears mechanism. A simplified semiclassical analysis yields B(M1) values in qualitative agreement with those expected for previously assigned configurations. The results suggest extremely low deformations for these dipole structures. In particular, the Sn-106 band appears to be the first example of almost pure magnetic rotation in a spherical nucleus. C1 Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. McMaster Univ, Dept Phys & Astron, Hamilton, ON L85 4M1, Canada. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. AECL Res, Chalk River Labs, Chalk River, ON K0J 1J0, Canada. FZ Rossendorf, D-01314 Dresden, Germany. RP Jenkins, DG (reprint author), Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. RI Lane, Gregory/A-7570-2011; Kruecken, Reiner/A-1640-2013 OI Lane, Gregory/0000-0003-2244-182X; Kruecken, Reiner/0000-0002-2755-8042 NR 20 TC 50 Z9 51 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 JUL 19 PY 1999 VL 83 IS 3 BP 500 EP 503 DI 10.1103/PhysRevLett.83.500 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100010 ER PT J AU Kanter, EP Dunford, RW Krassig, B Southworth, SH AF Kanter, EP Dunford, RW Krassig, B Southworth, SH TI Double K-vacancy production in molybdenum by X-ray photoionization SO PHYSICAL REVIEW LETTERS LA English DT Article ID HYPERSATELLITE SPECTRA; FLUORESCENCE YIELDS; HELIUM; STATE; ATOMS; IONIZATION; ABSORPTION; SEQUENCE; AUGER; IONS AB We report the observation of double K-vacancy production in x-ray photoionization of molybdenum. From these data we deduce the relative probabilities for production of double and single K vacancies by photon impact at 50 keV and report the most precise measure of the ratio of double to single K-vacancy production by photon impact in a heavy atom. That ratio provides an important probe of electron-electron correlations in high-Z atoms where theoretical descriptions must consider those correlations simultaneously with relativity. Our results suggest the need for theoretical treatments to properly deal with such systems. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Kanter, EP (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 35 TC 53 Z9 53 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 JUL 19 PY 1999 VL 83 IS 3 BP 508 EP 511 DI 10.1103/PhysRevLett.83.508 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100012 ER PT J AU Chu, YS You, H Tanzer, JA Lister, TE Nagy, Z AF Chu, YS You, H Tanzer, JA Lister, TE Nagy, Z TI Surface resonance X-ray scattering observation of core-electron binding-energy shifts of Pt(111)-surface atoms during electrochemical oxidation SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRYSTAL-TRUNCATION-ROD; FINE-STRUCTURE; REFLECTIVITY; ALLOY AB Surface resonance x-ray scattering, sensitive to the monolayer-level change of an oxidation state of a buried interface, is used for the investigation of electrochemical oxidation of Pt(111) single crystal surface. The strongly Q-dependent energy scans through the L-III resonance energy of Pt atoms were accounted for by a large increase of the electron binding energy of the surface atoms as a result of surface anodic oxidation. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Chu, YS (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI You, Hoydoo/A-6201-2011 OI You, Hoydoo/0000-0003-2996-9483 NR 21 TC 29 Z9 29 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 19 PY 1999 VL 83 IS 3 BP 552 EP 555 DI 10.1103/PhysRevLett.83.552 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100023 ER PT J AU Merkle, KL Thompson, LJ AF Merkle, KL Thompson, LJ TI High-resolution electron microscopy of twist and general grain boundaries SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-DIFFRACTION; ATOMIC-STRUCTURE; METALS; GOLD; FCC AB High-resolution imaging of atomic structures of twist and general grain boundaries (GBs) is reported in samples prepared by a thin-film technique in which [011] and [001] oriented An grains are epitaxially grown side by side, allowing the investigation of a wide range of GB geometries. GBs with tilt as well as twist components typically have structural modulations along the interface and often show a surprising amount of coherence between lattice planes crossing the interface. The [110], 90 degrees symmetric twist GB does not remain planar, but reconstructs into atomic-scale microfacets. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Merkle, KL (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 12 TC 19 Z9 19 U1 2 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 19 PY 1999 VL 83 IS 3 BP 556 EP 559 DI 10.1103/PhysRevLett.83.556 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100024 ER PT J AU Wang, J Tolan, M Seeck, OH Sinha, SK Bahr, O Rafailovich, MH Sokolov, J AF Wang, J Tolan, M Seeck, OH Sinha, SK Bahr, O Rafailovich, MH Sokolov, J TI Surfaces of strongly confined polymer thin films studied by X-ray scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID CAPILLARY WAVES; REFLECTIVITY; INTERFACES; WATER; FLUCTUATIONS; ROUGHNESS AB The surfaces of thermally annealed thin polystyrene films on silicon were investigated by specular and diffuse x-ray scattering. The data cannot be interpreted satisfactorily with capillary wave calculations assuming attractive van der Weals substrate film interactions. The analysis shows that polystyrene films coated on silicon substrates are in a strongly confined state even for film thicknesses much larger than the radius of gyration, possibly due to strong confinement that arises from the interaction. at the polymer/substrate interface and the viscoelastic behavior of the thin films. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. Univ Kiel, Inst Expt & Angew Phys, D-24098 Kiel, Germany. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Wang, J (reprint author), Argonne Natl Lab, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 22 TC 67 Z9 67 U1 3 U2 27 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 JUL 19 PY 1999 VL 83 IS 3 BP 564 EP 567 DI 10.1103/PhysRevLett.83.564 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100026 ER PT J AU Bickham, SR Kress, JD Collins, LA Stumpf, R AF Bickham, SR Kress, JD Collins, LA Stumpf, R TI Ab initio molecular dynamics studies of off-center displacements in CuCl SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE-DYNAMICS; COPPER HALIDES; ANOMALIES; PSEUDOPOTENTIALS; SEMICONDUCTOR; TRANSITION AB The unusual properties of CuCl have previously been interpreted using models that focus either on anharmonicity or off-center displacements from the zinc blends structure. We use nb initio molecular dynamics to show that both are important in determining the behavior of CuCl. At low temperatures, most of the Cu ions are located in off-center sites along the (111) directions. The lattice undergoes gradual transition from static to dynamic disorder with rising temperature. Increasing pressure favors the zinc blende structure, in agreement with recent Raman experiments. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Motorola Inc, Computat Mat Grp, Los Alamos, NM 87545 USA. RP Bickham, SR (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 30 TC 14 Z9 14 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 JUL 19 PY 1999 VL 83 IS 3 BP 568 EP 571 DI 10.1103/PhysRevLett.83.568 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100027 ER PT J AU Julien, MH Borsa, F Carretta, P Horvatic, M Berthier, C Lin, CT AF Julien, MH Borsa, F Carretta, P Horvatic, M Berthier, C Lin, CT TI Charge segregation, cluster spin glass, and superconductivity in La1.94Sr0.06CuO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONIC PHASE-SEPARATION; MAGNETIC FLUCTUATIONS; NORMAL-STATE; LA2-XSRXCUO4; RELAXATION; ORDER; NQR; LA1.6-XND0.4SRXCUO4; ANTIFERROMAGNETISM; COEXISTENCE AB A Cu-63 and La-139 NMR/NQR study of superconducting (T-c = 8 K) La1.94Sr0.06CuO4 single crystal is reported. Coexistence of spin-glass and superconducting phases is found below similar to 5 K from La-139 NMR relaxation. Cu-63 and La-139 NMR spectra show that, upon cooling, CuO2 planes progressively separate into two magnetic phases, one of them having enhanced antiferromagnetic correlations. These results establish the antiferromagnetic-cluster nature of the spin glass. We discuss how this phase can be related to the: microsegregation of mobile holes and to the possible pinning of charge stripes. C1 Ist Nazl Fis Nucl, Dipartimento Fis A Volta, Unita Pavia, I-27100 Pavia, Italy. Iowa State Univ, Dept Phys, Ames Lab, Ames, IA 50011 USA. CNRS, Grenoble High Magnet Field Lab, F-38042 Grenoble 9, France. MPI, FKF, F-38042 Grenoble 9, France. Univ Grenoble 1, Spectrometrie Phys Lab, F-38402 St Martin Dheres, France. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. RP Ist Nazl Fis Nucl, Dipartimento Fis A Volta, Unita Pavia, Via Bassi 6, I-27100 Pavia, Italy. RI Berthier, Claude/D-9686-2011; Julien, Marc-Henri/A-2352-2010 OI Berthier, Claude/0000-0001-6796-0506; NR 38 TC 91 Z9 91 U1 2 U2 11 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 JUL 19 PY 1999 VL 83 IS 3 BP 604 EP 607 DI 10.1103/PhysRevLett.83.604 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100036 ER PT J AU Carlson, EW Kivelson, SA Emery, VJ Manousakis, E AF Carlson, EW Kivelson, SA Emery, VJ Manousakis, E TI Classical phase fluctuations in high temperature superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-C SUPERCONDUCTORS; PENETRATION-DEPTH MEASUREMENTS; CRITICAL-BEHAVIOR; NORMAL-STATE; ANISOTROPY; DENSITY; CUPRATE; MASS; GAP AB Phase fluctuations of the superconducting order parameter play a larger role in the cuprates than in conventional BCS superconductors because of the low superfluid density rho(s) of a doped insulator. In this paper, we analyze an XY model of classical phase fluctuations in the high temperature superconductors using a low temperature expansion and Monte Carlo simulations. In agreement with experiment, the value of rho(s) at temperature T = 0 is a quite robust predictor of T-c, and the evolution of rho(s) with T, including its T-linear behavior at low temperature, is insensitive to microscopic details. C1 Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Florida State Univ, MARTECH, Tallahassee, FL 32306 USA. RP Carlson, EW (reprint author), Univ Calif Los Angeles, Dept Phys, 405 Hilgard Ave, Los Angeles, CA 90095 USA. NR 27 TC 90 Z9 90 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 19 PY 1999 VL 83 IS 3 BP 612 EP 615 DI 10.1103/PhysRevLett.83.612 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100038 ER PT J AU Uchiyama, Y Sasago, Y Tsukada, I Uchinokura, K Zheludev, A Hayashi, T Miura, N Boni, P AF Uchiyama, Y Sasago, Y Tsukada, I Uchinokura, K Zheludev, A Hayashi, T Miura, N Boni, P TI Spin-vacancy-induced long-range order in a new haldane-gap antiferromagnet SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHAIN HEISENBERG-ANTIFERROMAGNET; BOND GROUND-STATES; QUANTUM ANTIFERROMAGNETS; PEIERLS TRANSITION; MAGNETIC-FIELD; CUGEO3; DYNAMICS; IMPURITY; CUPRATE; CSNICL3 AB Magnetic susceptibility, high-field magnetization, and inelastic neutron scattering experiments are used to study the magnetic properties of a new S = 1 quasi-one-dimensional antiferromagnet PbNi2V2O8. Interchain interactions are shown to be almost, but not quite, strong enough to destroy the nonmagnetic singlet ground state and the energy gap in the magnetic excitation spectrum. Substituting nonmagnetic Mg2+ (S = 0) ions for Ni2+ (S = 1) induces a magnetically ordered state at low temperatures. To our knowledge this is the first observation of doping-induced long-range order in a Haldane-gap system. C1 Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan. Univ Tokyo, Dept Adv Mat Sci, Bunkyo Ku, Tokyo 1138656, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 1068666, Japan. ETH Zurich, Neutron Scattering Lab, CH-5232 Villigen, Switzerland. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. RP Uchinokura, K (reprint author), Univ Tokyo, Dept Appl Phys, Bunkyo Ku, 6th Engn Bldg, Tokyo 1138656, Japan. NR 25 TC 148 Z9 149 U1 3 U2 16 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 JUL 19 PY 1999 VL 83 IS 3 BP 632 EP 635 DI 10.1103/PhysRevLett.83.632 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100043 ER PT J AU Cleve, R Gottesman, D Lo, HK AF Cleve, R Gottesman, D Lo, HK TI How to share a quantum secret SO PHYSICAL REVIEW LETTERS LA English DT Article ID ERROR-CORRECTING CODES AB We investigate the concept of quantum secret sharing. In a (k, ta) threshold scheme, a secret quantum state is divided into n shares such that any k of those shares can be used to reconstruct the secret, but any set of k - 1 or fewer shares contains absolutely no information about the secret. We show that the only constraint on the existence of threshold schemes comes from the quantum "no-cloning theorem," which requires that n < 2k, and we give efficient constructions of all threshold schemes. We also show that, for k less than or equal to n < 2k - 1, then any (k, n) threshold scheme must distribute information that is globally in a mixed state. C1 Univ Calgary, Dept Comp Sci, Calgary, AB T2N 1N4, Canada. Univ Calif Los Alamos Natl Lab, Grp T6, Los Alamos, NM 87545 USA. Hewlett Packard Labs, Bristol BS34 8QZ, Avon, England. RP Cleve, R (reprint author), Univ Calgary, Dept Comp Sci, Calgary, AB T2N 1N4, Canada. NR 24 TC 674 Z9 715 U1 5 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 JUL 19 PY 1999 VL 83 IS 3 BP 648 EP 651 DI 10.1103/PhysRevLett.83.648 PG 4 WC Physics, Multidisciplinary SC Physics GA 216MU UT WOS:000081447100047 ER PT J AU Hively, LM Gailey, PC Protopopescu, VA AF Hively, LM Gailey, PC Protopopescu, VA TI Detecting dynamical change in nonlinear time series SO PHYSICS LETTERS A LA English DT Article ID OBSERVED CHAOTIC DATA; STRANGE ATTRACTORS; NONSTATIONARITY; DIMENSIONS; SYSTEMS AB We present a robust, model-independent technique for measuring changes in the dynamics underlying nonlinear time-serial data. After constructing discrete density distributions of phase-space points on the attractor for time-windowed data sets, we measure the dissimilarity between density distributions via L-1-distance and chi(2) statistics. The discriminating power of the new measures is first tested on the Lorenz model and then applied to EEG data to detect the transition between non-seizure and epileptic activity. We find a clear superiority of the new measures in comparison to traditional nonlinear measures as discriminators of changing dynamics. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Hively, LM (reprint author), Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA. NR 31 TC 33 Z9 35 U1 0 U2 1 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 JUL 19 PY 1999 VL 258 IS 2-3 BP 103 EP 114 DI 10.1016/S0375-9601(99)00342-4 PG 12 WC Physics, Multidisciplinary SC Physics GA 219NQ UT WOS:000081613700006 ER PT J AU Galande, S Kohwi-Shigematso, T AF Galande, S Kohwi-Shigematso, T TI Poly(ADP-ribose) polymerase and Ku autoantigen form a complex and synergistically bind to matrix attachment sequences SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID CHROMOSOMAL LOOP ANCHORAGE; NUCLEAR MATRIX; DNA-BINDING; CELL-CYCLE; IN-VIVO; V(D)J RECOMBINATION; DEFICIENT CELLS; REPLICATION; PROTEIN; TRANSCRIPTION AB Genomic sequences with a cluster of ATC sequence stretches where one strand consists exclusively of well mixed As, Ts, and Cs confer high base unpairing propensity under negative superhelical strain. Such base unpairing regions (BURs) are typically found in scaffold or matrix attachment regions (SARs/MARs) that are thought to contribute to the formation of the loop domain structure of chromatin, Several proteins, including cell type-specific proteins, have been identified that bind specifically to double-stranded BURs either in. vitro or in vivo. By using BUR-affinity chromatography to isolate BUR-binding proteins from breast cancer SK-BR-3 cells, we almost exclusively obtained a complex of poly(ADP-ribose) polymerase (PARP) and DNA-dependent protein kinase (DNA-PK), Both PARP and DNA-PK are activated by DNA strand breaks and are implicated in DNA repair, recombination, DNA replication, and transcription. In contrast to the previous notion that PARP and Ku autoantigen, the DNA-binding subunit of DNA-PK, mainly bind to free ends of DNA, here we show that both proteins individually bind BURs with high affinity and specificity in an end-independent manner using closed circular BUR-containing DNA substrates. We further demonstrate that PARR and Ku autoantigen form a molecular complex in vivo and in vitro in the absence of DNA, and as a functional consequence, their affinity to the BURs are synergistically enhanced. ADP-ribosylation of the nuclear extract abrogated the BUR binding activity of this complex. These results provide a mechanistic link toward understanding the functional overlap of PARP and DNA PK and suggest a novel role for these proteins in the regulation of chromatin structure and function. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Kohwi-Shigematso, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,Mail Stop 70A-1118, Berkeley, CA 94720 USA. NR 46 TC 138 Z9 140 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUL 16 PY 1999 VL 274 IS 29 BP 20521 EP 20528 DI 10.1074/jbc.274.29.20521 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 216JE UT WOS:000081438300074 PM 10400681 ER PT J AU Farkas, T Zhong, GM Guiochon, G AF Farkas, T Zhong, GM Guiochon, G TI Validity of Darcy's law at low flow-rates in liquid chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE Darcy's law; flow-rate; ethylene glycol ID PACKED SPHERES; POROUS-MEDIA; COLUMNS AB The applicability of Darcy's law at extremely low flow velocities has been questioned in the scientific literature. It was investigated using a simple chromatographic system. Ethylene glycol (viscosity, 19.9 cP at 20 degrees C) was pumped through 10 to 25 cm long chromatographic columns packed with small porous spherical particles (size, 5 to 10 mu m) The dependence of the linear velocity of this liquid on the inlet pressure was found to be linear in the range of Reynolds numbers (based on particle diameter) between Re=1.10(-6) and 1.10(-4). These results contradict earlier reports by Fand et al. and more recent findings by Kececioglu and Jiang that suggest a limited applicability of Darcy's law to the range Re=0.3 to 0.7. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37803 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 15 TC 16 Z9 16 U1 4 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD JUL 16 PY 1999 VL 849 IS 1 BP 35 EP 43 DI 10.1016/S0021-9673(99)00482-3 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 219LW UT WOS:000081609600003 ER PT J AU Quinones, I Stanley, B Guiochon, G AF Quinones, I Stanley, B Guiochon, G TI Estimation of the adsorption energy distributions for the Jovanovic-Freundlich isotherm model with Jovanovic local behavior SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE adsorption isotherms; Jovanovic-Freundlich isotherms; adsorption energy distributions; thermodynamic parameters; organochlorine compounds ID HETEROGENEOUS SURFACES; GAS-MIXTURES; SILICA-GEL AB The successful design of many modern separation processes as the overloaded chromatographic separations require an accurate knowledge of the associated adsorption equilibria. It is well known that the characterization of the adsorbent heterogeneity plays an important role in the understanding of the adsorption equilibria. In a previous paper, a new Jovanovic-Freundlich isotherm model for single-component adsorption on heterogeneous surfaces was proposed. Also, the adsorption energy distributions (AEDs) corresponding to the new model for Langmuir local behavior were derived and evaluated for the specific case of the adsorption of a series of chlorinated hydrocarbons on silica gel. In the present study, the adsorption energy distributions corresponding to the Jovanovic-Freundlich model with Jovanovic local behavior are evaluated for the same set of experimental data. In order to provide a basis for comparison, adsorption energy distributions were also estimated for the given set of data via an established expectation-maximization procedure which does not assume any particular model for the overall isotherm. The results presented in these paper complement the previous findings and provide new insights into the features of the Jovanovic-Freundlich isotherm model, which could be useful both in the correlation of single-component adsorption data and in the prediction of multicomponent equilibria. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Calif State Univ San Bernardino, Dept Chem, San Bernardino, CA 92407 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 18 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD JUL 16 PY 1999 VL 849 IS 1 BP 45 EP 60 DI 10.1016/S0021-9673(99)00509-9 PG 16 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 219LW UT WOS:000081609600004 ER PT J AU Boettcher, S AF Boettcher, S TI Extremal optimization of graph partitioning at the percolation threshold SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID SPIN-GLASSES; STATISTICAL-MECHANICS; EVOLUTION; CRITICALITY; MODELS AB The benefits of a recently proposed method to approximate hard optimization problems are demonstrated on the graph partitioning problem. The performance of this new method, called extremal optimization (EO), is compared with simulated annealing (SA) in extensive numerical simulations. While generally a complex (NP-hard) problem, the optimization of the graph partitions is particularly difficult for sparse graphs with average connectivities near the percolation threshold. At this threshold, the relative error of SA for large graphs is found to diverge relative to EO at equalized runtime. On the other hand, EO, based on the extremal dynamics of self-organized critical systems, reproduces known results about optimal partitions at this critical point quite well. C1 Emory Univ, Dept Phys, Atlanta, GA 30322 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Boettcher, S (reprint author), Emory Univ, Dept Phys, Atlanta, GA 30322 USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 28 TC 38 Z9 40 U1 2 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD JUL 16 PY 1999 VL 32 IS 28 BP 5201 EP 5211 DI 10.1088/0305-4470/32/28/302 PG 11 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 222BV UT WOS:000081764300004 ER PT J AU Rithidech, K Dunn, JJ Bond, VP Gordon, CR Cronkite, EP AF Rithidech, K Dunn, JJ Bond, VP Gordon, CR Cronkite, EP TI Characterization of genetic instability in radiation- and benzene-induced murine acute leukemia SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article; Proceedings Paper CT 3rd International Conference on Environmental Mutagens in Human Populations CY NOV 28-DEC 04, 1998 CL BANGKOK, THAILAND DE genetic instability; G-banding; fluorescence in situ hybridization (FISH); radiation; benzene; leukemia ID ACUTE MYELOID-LEUKEMIA; IN-SITU HYBRIDIZATION; FLUORESCENCE INSITU HYBRIDIZATION; ACUTE LYMPHOBLASTIC-LEUKEMIA; ACUTE MYELOBLASTIC-LEUKEMIA; T-CELL LEUKEMIA; Y-CHROMOSOME; PAINTING PROBES; BONE-MARROW; DNA PROBES AB This study, using the CBA/Ca mouse as a model, compares genetic lesions associated with radiation- and benzene-induced acute leukemias. Specific types of leukemia included in the analyses are radiation-induced acute myeloid leukemia (ML), and benzene-induced lymphoblastic leukemias, lymphomas, or mix-lineage leukemias. These leukemias have histopathological characteristics similar to those seen in human acute leukemias. G-band cytogenetic analysis showed that specific deletions involving regions D-E of one copy of mouse chromosome 2 [del(2)(D-E)] were frequently associated in both radiation- and benzene-induced acute leukemias. In addition, translocations of chr2(D-E) were also observed in some cases. These results suggest an important role of chr2(D-E) deletions and translocations in the development of radiation- and benzene-induced murine acute leukemias. Fluorescence in situ hybridization with DNA probes specific for 2(D-E), constructed in our laboratory by means of chromosomal microdissection and PCR amplification, also demonstrate 2(D-E) deletions and/or translocations in these leukemic cells. Aneuploidy of chromosomes 3, 15, 16, and Y were also frequently detected in benzene-induced leukemic cells with or without lesions on chr2. These cytogenetic findings support the previous observations that metabolites of benzene lead to spindle-fiber disruption or abnormal cytokinesis in exposed animals. In summary, genetic instabilities observed in leukemic cells isolated from mice that had developed leukemia after exposure to radiation or benzene are syntenic with those frequently detected in patients with myelodysplastic syndrome, acute ML, and acute lymphoblastic leukemia. Thus, the CBA/Ca mouse has several characteristics that make it an excellent model for the study of radiation or benzene leukemogenesis in humans. (C) 1999 Elsevier Science B.V. All rights reserved. C1 SUNY Stony Brook, Dept Pathol, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Washington State Univ, Richland, WA 99352 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Rithidech, K (reprint author), SUNY Stony Brook, Dept Pathol, BHS T9, Stony Brook, NY 11794 USA. NR 63 TC 21 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD JUL 16 PY 1999 VL 428 IS 1-2 BP 33 EP 39 DI 10.1016/S1383-5742(99)00029-0 PG 7 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 234RU UT WOS:000082498800006 PM 10517976 ER PT J AU Xu, NX Pasa-Tolic, L Smith, RD Ni, SS Thrall, BD AF Xu, NX Pasa-Tolic, L Smith, RD Ni, SS Thrall, BD TI Electrospray ionization-mass spectrometry study of the interaction of cisplatin-adducted oligonucleotides with human XPA minimal binding domain protein SO ANALYTICAL BIOCHEMISTRY LA English DT Article DE protein/DNA interactions; oligonucleotide adduction; nucleotide excision repair; electrospray ionization mass spectrometry ID NUCLEOTIDE EXCISION-REPAIR; A COMPLEMENTING PROTEIN; DNA-DAMAGE RECOGNITION; XERODERMA-PIGMENTOSUM; TRANSCRIPTION FACTOR; MAMMALIAN-CELLS; ASSOCIATION; COMPLEXES; ERCC1; CLEANUP AB Nucleotide excision repair (NER) is the process responsible for eliminating most ultraviolet (UV) radiation damage from DNA, as well as base alterations caused by a variety of mutagens. The xeroderma pigmentosum group A complementing protein (XPA) is believed to be involved in the early step of NER by recognizing and binding damaged DNA. Recent work has suggested that electrospray ionization-mass spectrometry (ESI-MS) can be an effective tool for the study of protein-DNA complexes. We have used ESI-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry to examine the cisplatin-adducted oligonucleotide and its interaction with the human XPA minimal binding domain (XPA-MBD). High-resolution FTICR experiments of the binding products showed that both double-stranded damaged 20-mer and double-stranded undamaged 20-mer formed 1:1 noncovalent complexes with XPA-MBD. A 2:1 binding stoichiometry complex was also observed between XPA-MBD and double-stranded damaged 20-mer. Competitive binding experiments indicated only slightly preferential binding of XPA-MBD with the double-stranded damaged 20-mer compared to the undamaged 20-mer. The results demonstrate that ESI-FTICR mass spectrometry provides a fast and efficient approach for characterizing weak protein-DNA interactions such as the binding between XPA-MBD and a 20-mer oligonucleotide system. (C) 1999 Academic Press. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Lab, Mol Biosci Lab, Richland, WA 99352 USA. RP Xu, NX (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 44 TC 34 Z9 36 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD JUL 15 PY 1999 VL 272 IS 1 BP 26 EP 33 DI 10.1006/abio.1999.4143 PG 8 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 219PX UT WOS:000081616600004 PM 10405289 ER PT J AU Bruce, JE Anderson, GA Wen, J Harkewicz, R Smith, RD AF Bruce, JE Anderson, GA Wen, J Harkewicz, R Smith, RD TI High mass-measurement accuracy and 100% sequence coverage of enzymatically digested bovine serum albumin from an ESI-FTICR mass spectrum SO ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROSPRAY-IONIZATION; LARGE BIOMOLECULES; SPECTROMETRY; IDENTIFICATION; PROTEINS AB The application of Fourier transform ion cyclotron resonance (FTICR) mass spectrometry to the analysis of polypeptide mixtures resulting from proteolytic digestion is described. A new 11.5-T FTICR mass spectrometer has been applied for the analysis of tryptic digestion mixtures of the protein bovine serum albumin (BSA), The improved cyclotron frequency stability;and reduced frequency shifts observed over a wide range of trapped ion population sizes provide the ability to signal average spectra without degrading mass measurement accuracy, requiring internal calibration or advanced data processing schemes to compensate for variations in ion cyclotron signals brought about by different population sizes. A total of 100 spectra were signal-averaged leading to the observation of a total of 123 isotope distributions with a signal-to-noise ratio greater than 3:1, From those distributions, 86 can be ascribed to tryptic fragments; of BSA on the basis of mass measurement errors of 10 ppm or less. Of these, 71 were within 2 ppm error limits corresponding to complete amino acid sequence cover;sge and an average error of 0.77 ppm. These results indicate that high-accuracy measurements are feasible for a large number of species detected simultaneously without the necessity for internal calibration and indicate the potential of such measurements, when combined with chromatographic separations, for facilitating more rapid identification of large numbers of proteins. C1 Pacific NW Natl Lab, Environm & Mol Sci Lab, Separat & Mass Spectrometry Grp, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Natl Lab, Environm & Mol Sci Lab, Separat & Mass Spectrometry Grp, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 18 TC 81 Z9 83 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 15 PY 1999 VL 71 IS 14 BP 2595 EP 2599 DI 10.1021/ac990231s PG 5 WC Chemistry, Analytical SC Chemistry GA 216VM UT WOS:000081465200001 PM 10424157 ER PT J AU Xue, G Pang, HM Yeung, ES AF Xue, G Pang, HM Yeung, ES TI Multiplexed capillary zone electrophoresis and micellar electrokinetic chromatography with internal standardization SO ANALYTICAL CHEMISTRY LA English DT Article ID ARRAY ELECTROPHORESIS; SEPARATION; SULFATE; CHIPS; FLOW AB Although liquid chromatography and gas chromatography are the main workhorses in the analytical laboratory, samples can only be analyzed consecutively in an instrument. In this study, capillary zone electrophoresis and micellar electrokinetic chromatography separations are performed in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. C1 USDOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), USDOE, Ames Lab, Ames, IA 50011 USA. NR 26 TC 37 Z9 40 U1 3 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 15 PY 1999 VL 71 IS 14 BP 2642 EP 2649 DI 10.1021/ac990062b PG 8 WC Chemistry, Analytical SC Chemistry GA 216VM UT WOS:000081465200007 PM 10424161 ER PT J AU Bond, AH Chiarizia, R Huber, VJ Dietz, ML Herlinger, AW Hay, BP AF Bond, AH Chiarizia, R Huber, VJ Dietz, ML Herlinger, AW Hay, BP TI Synergistic solvent extraction of alkaline earth cations by mixtures of di-n-octylphosphoric acid and stereoisomers of dicyclohexano-18-crown-6 SO ANALYTICAL CHEMISTRY LA English DT Article ID DIDODECYLNAPHTHALENE SULFONIC-ACID; ATOMIC-ABSORPTION SPECTROMETRY; ION-PAIR EXTRACTION; CROWN-ETHERS; TRIVALENT LANTHANIDES; SELECTIVE EXTRACTION; CONFORMATIONAL-ANALYSIS; METAL-IONS; THENOYLTRIFLUOROACETONE COMPLEX; DI(2-ETHYLHEXYL)PHOSPHORIC ACID AB The partitioning of Ca(TI), Sr(II), and Ba(II) in solvent extraction systems comprising di-n-octylphosphoric acid (HDOP) and individual stereoisomers of dicyclohexano-18-crown-6 (DCH18C6) in toluene has been investigated at 23(2) degrees C, Results of vapor pressure osmometric experiments, continuous variation studies, single- and double-extractant dependencies, and acid dependencies have been used to determine the stoichiometries of the extracted complexes, Extraction of Ca(II) by HDOP alone affords Ca(H(DOP)(2))(2) HDOP as the extracted species, and no synergism is observed in the presence of DCH18C6, presumably due to the strong complexation of Ca(II) with HDOP and the strained complexes this cation forms with DCH18C6. In the absence of DCH18C6, Sr(II) and Ba(II) are extracted as the M(H(DOP)(2))(2) . 2HDOP (M = Sr or Ba) complexes. Upon addition of DCH18C6, the extracted complexes are formulated as M(DCH18C6)(H(DOP)(2))(2) (M = Sr or Ba), with Ba(II) showing greater synergistic effects than Sr(II), The effectiveness of the DCH18C6 stereoisomers as synergists decreases in the following order: cis-syn-cis > cis-anti-cis > cis-trans > trans-syn-trans > trans-anti>trans, This sequence has been explained by correlating the logarithm of the synergistic adduct formation constants with the ligand strain energies of the DCH18C6 stereoisomers calculated using molecular mechanics methods. Those stereoisomers having the largest strain energies afford the lowest extraction and synergistic adduct formation constants. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Loyola Univ, Chicago, IL 60226 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM mark-dietz@qmgate.anl.gov NR 84 TC 29 Z9 29 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD JUL 15 PY 1999 VL 71 IS 14 BP 2757 EP 2765 DI 10.1021/ac9900681 PG 9 WC Chemistry, Analytical SC Chemistry GA 216VM UT WOS:000081465200023 ER PT J AU Szarka, AZ Curtiss, LA Miller, JR AF Szarka, AZ Curtiss, LA Miller, JR TI Calculation of temporary anion states using density functional theory SO CHEMICAL PHYSICS LA English DT Article ID ELECTRON TRANSMISSION SPECTROSCOPY; NEGATIVE-ION STATES; IONIZATION-POTENTIALS; CONFIGURATION-INTERACTION; STABILIZATION METHOD; BASIS-SETS; GAS-PHASE; AFFINITIES; ENERGIES; COMPUTATION AB Density functional theory (DFT) was examined for computing energies of temporary anions having negative electron affinities ranging from - 8.0 to - 0.2 eV. The calculated electron affinities are in good agreement with experiment for rr states and low-energy sigma* states. The dependence of the DFT results on basis set was investigated. Comparisons are made with results from traditional ab initio molecular orbital theory based on Koopmans' theorem (KT) and energy difference methods (Delta HF and Delta MP2). It is shown that DFT methods provide an improvement over use of ab initio molecular orbital methods. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Brookhaven Natl Lab, Dept Chem, Bld 555A, Upton, NY 11973 USA. NR 56 TC 21 Z9 21 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 EI 1873-4421 J9 CHEM PHYS JI Chem. Phys. PD JUL 15 PY 1999 VL 246 IS 1-3 BP 147 EP 155 DI 10.1016/S0301-0104(99)00120-2 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227FP UT WOS:000082068600012 ER PT J AU Sohlberg, K AF Sohlberg, K TI Mechanism of efficient V-V in collisions of N-2(+) (nu > 0) with N-2 SO CHEMICAL PHYSICS LA English DT Article ID ION-MOLECULE REACTIONS; CHARGE-EXCHANGE; VIBRATIONAL-ENERGY; CO+-CO; DYNAMICS; DIATOM AB Fully quantum mechanical calculations of state-to-state cross sections in vibrationally deactivating collisions of N-2(+)(nu > 0) with N-2 are reported. A study of the opacity function confirms that V-V is a longer range process than V-T, as previously inferred from experiments, but only marginally so. Variations in the transition probability are found to be of greater importance in determining the state-to-state cross sections. Multi-quantum V-V, while weaker than single-quantum V-V, is competitive with single-quantum V-T processes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Sohlberg, K (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUL 15 PY 1999 VL 246 IS 1-3 BP 307 EP 313 DI 10.1016/S0301-0104(99)00190-1 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227FP UT WOS:000082068600024 ER PT J AU Hinkley, TK Lamothe, PJ Wilson, SA Finnegan, DL Gerlach, TM AF Hinkley, TK Lamothe, PJ Wilson, SA Finnegan, DL Gerlach, TM TI Metal emissions from Kilauea, and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE volcanoes; trace elements; trace metals; injection degassing; Kilauea ID ATMOSPHERIC TRACE-METALS; HEAVY-METALS; SULFUR-DIOXIDE; MOUNT ETNA; ELEMENTS; SNOW; PARTICULATE; HEMISPHERE; ENRICHMENT; POLLUTION AB Measurements of a large suite of metals (Pb, Cd, Cu, Zn and several others) and sulfur at Kilauea volcano over an extended period of time has yielded a detailed record of the atmospheric injection of ordinarily-rare metals from this quiescently degassing volcano, representative of an important type. We have combined the Kilauea data with data of recent studies by others (emissions from volcanoes in the Indonesian are; the large Laki eruption of two centuries ago; Etna; estimates of total volcanic emissions of sulfur) to form the basis for a new working estimate of the rate of worldwide injection of metals to the atmosphere by volcanoes. The new estimate is that volcanoes inject a substantially smaller mass of ordinarily-rare metals into the atmosphere than was stated in a widely cited previous estimate [J.O. Nriagu, A global assessment of natural sources of atmospheric trace metals, Nature 338 (1989) 47-49]. Our estimate, which is an upper limit, is an annual injection mass of about 10,000 tons of the metals considered, versus the earlier estimate of about 23,000 tons. Also, the proportions of the metals are substantially different in our new estimate. Published by Elsevier Science B.V. C1 980 US Geol Survey, Denver, CO 80225 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. US Geol Survey, Vancouver, WA USA. RP Hinkley, TK (reprint author), 980 US Geol Survey, Box 25046 Fed Ctr, Denver, CO 80225 USA. NR 32 TC 118 Z9 119 U1 0 U2 19 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 JUL 15 PY 1999 VL 170 IS 3 BP 315 EP 325 DI 10.1016/S0012-821X(99)00103-X PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 215DY UT WOS:000081367700012 ER PT J AU Bargar, JR Reitmeyer, R Davis, JA AF Bargar, JR Reitmeyer, R Davis, JA TI Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CARBONATE COMPLEXES; AQUEOUS-SOLUTION; URANYL; GOETHITE; MODEL; ION AB Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)-carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used attenuated total reflectance Fourier transform infrared (ATR-FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of=FeO(surface)-U(VI)-carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)-carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)-carbonato complexes;, which are trace constituents at pH < 6. This result indicates the inadequacy of the common modeling assumption that the compositions and predominance of adsorbed species can be inferred from aqueous species. By extension, adsorbed carbonate complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium. C1 Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. US Geol Survey, Div Water Resources, Menlo Pk, CA 94025 USA. RP Bargar, JR (reprint author), Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. EM bargar@ssrl.slac.stanford.edu NR 25 TC 158 Z9 161 U1 7 U2 75 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 JUL 15 PY 1999 VL 33 IS 14 BP 2481 EP 2484 DI 10.1021/es990048g PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 217CA UT WOS:000081480900026 ER PT J AU Clark, JF Chamberlin, RM Abney, KD Strauss, SH AF Clark, JF Chamberlin, RM Abney, KD Strauss, SH TI Design and use of redox-recyclable organometallic extractants for the cationic radionuclides Cs-137(+) and Sr-90(2+) from waste solutions SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID COMPLEX AB Two new redox-active organometallic extractants for the redox-recyclable extraction and recovery ((RER)-E-2) of the cationic radionuclides Cs-137(+) and Sr-90(2+) from aqueous waste simulants, Na[Fe(eta(5)-C5H5)(eta(5)-(3)-1,2-C2B9H9(n-C12H25)(2))] (Na+I-) and Na[Fe(eta(5)-C5H5)(eta(5)-(3)-1,2-C2B9H7(n-C12H25)(2)-9,12-Br-2)] (Na+II-), were synthesized and investigated. When diluted with toluene or xylenes, they extracted Cs+ from aqueous waste simulants such as (i) 1 mol L-1 NaOH + 1 mol L-1 NaNO3, (ii) 1 mol L-1 HNO3, and/or (iii) 1 mol L-1 NaCl, with D(Cs) values that ranged from 5 to 20; the corresponding D(Sr) values were less than or equal to 0.04. The addition of poly(ethylene glycol) as a co-diluent increased D(Sr) values to as high as 33 but decreased D(Cs) values by a factor of 2-10, depending on conditions. When separated from the raffinate and exposed to air, the extractant-containing organic phase released greater than or equal to 88% of its radioactivity in the form of a solid precipitate of minimal volume. When a small amount of water was present during this procedure, the extractant-containing organic phase released greater than or equal to 99% of its radioactivity to the new aqueous phase. When an oxidized dilute extractant was rereduced and used for a second (RER)-E-2 cycle, the D(Cs) value was unchanged. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. RP Clark, JF (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-11,Mail Stop J514, Los Alamos, NM 87545 USA. RI Chamberlin, Rebecca/A-1335-2011 OI Chamberlin, Rebecca/0000-0001-6468-7778 NR 11 TC 4 Z9 5 U1 0 U2 2 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 JUL 15 PY 1999 VL 33 IS 14 BP 2489 EP 2491 DI 10.1021/es9810585 PG 3 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 217CA UT WOS:000081480900028 ER PT J AU Wright, TJ Costa, JL Naranjo, C Francis-West, P Altherr, MR AF Wright, TJ Costa, JL Naranjo, C Francis-West, P Altherr, MR TI Comparative analysis of a novel gene from the Wolf-Hirschhorn/Pitt-Rogers-Danks syndrome critical region SO GENOMICS LA English DT Article ID BONE MORPHOGENETIC PROTEINS; DISEASE GENE; SEQUENCES; POLYADENYLATION; CONFIRMATION; CHROMOSOME-4; EXPRESSION; DELETION; PATHWAY; LIMB AB Wolf-Hirschhorn syndrome (WHS) is a multiple malformation syndrome characterized by mental and developmental defects resulting from the absence of a segment of one chromosome 4 short arm (4p16.3). Recently, Pitt-Rogers-Danks syndrome (PRDS), which is also due to a deletion of chromosome 4p16.3, has been shown to be allelic to WHS. Due to the complex and variable expression of these disorders, it is thought that WHS/PRDS results from a segmental aneusomy of 4p resulting in haploinsufficieny of an undefined number of genes that contribute to the phenotype. In an effort to identify genes that contribute to human development and whose absence may contribute to the phenotype associated with these syndromes, we have generated a transcript map of the 165-kb critical region and have identified a number of potential genes. One of these genes, WHSC2, which was identified with the IMAGE cDNA clone 53283, has been characterized. Sequence analysis defined an open reading frame of 1584 bp (528 amino acids), and transcript analysis detected a 2.4-kb transcript in all fetal and adult tissues tested. In parallel, the mouse homologue was isolated and characterized. Mouse sequence analysis and the pattern of expression are consistent with the clone being the murine equivalent of the human WHSC2 gene (designated Whsc2h). The data from sequence and transcript analysis of this new human gene in combination with the lack of significant similarity to proteins of known function imply that it represents a novel gene. Most importantly, its location within the WHSCR suggests that this gene may play a role in the phenotype of the Wolf-Hirschhorn/Pitt-Rogers-Danks syndrome. (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Genom Grp, Los Alamos, NM 87545 USA. UMDS, Guys Hosp, Dept Craniofacial Dev, London SE1 9RT, England. RP Altherr, MR (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Genom Grp, MS M888, Los Alamos, NM 87545 USA. RI Costa, Jessica/E-2234-2011 OI Costa, Jessica/0000-0002-5813-3258 NR 32 TC 42 Z9 45 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD JUL 15 PY 1999 VL 59 IS 2 BP 203 EP 212 DI 10.1006/geno.1999.5871 PG 10 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 221YZ UT WOS:000081756600011 PM 10409432 ER PT J AU Disselkamp, RS Chapman, EG Barchet, WR Colson, SD Howd, CD AF Disselkamp, RS Chapman, EG Barchet, WR Colson, SD Howd, CD TI BrCl production in NaBr/NaCl/HNO3/O-3 solutions representative of sea-salt aerosols in the marine boundary layer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INORGANIC CHLORINE GASES; OZONE DEPLETION; BROMINE; PARTICLES; RELEASE; AIR; KINETICS AB Atomic bromine and chlorine liberated from seasalt aerosol is thought to play an important role in chemistry of the marine boundary layer. Despite numerous modeling studies, no prior experimental investigations pf the oxidation of halide species contained in simulated, or actual, sea-salt solutions have been performed. We present laboratory data that examines chemistry in NaBr/NaCl/KNO3/O-3 solutions at 290 K. Ozonation experiments were performed by flowing atone in air through a nitric acid/salt solution and monitoring pH with time using an ion-sensitive electrode. The rate of oxidation was observed to be first order in ozone concentration and to have a non-first order bromide concentration dependence. Ion chromatography was used to measure both bromide disappearance as well as oxidation products formed during the course of the reactions studied. Our measurements of the oxidation rate versus ion concentration indicate that the high ionic strength present in sea-salt aerosol will possess unique kinetics different from dilute solution behavior. In addition, our results are consistent with the reaction sequence O-3 + H+ + Br- --> O-2 + HOBr and HOBr + Cl- + H+ --> BrCl + H2O. These observations support the HOBr mediated Cl- oxidation process proposed previously (Vogt et al., 1996). C1 Pacific NW Natl Lab, Atmospher Sci & Global Change Resources, Richland, WA 99352 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Michigan, Dept Chem, Flint, MI 48502 USA. RP Disselkamp, RS (reprint author), Pacific NW Natl Lab, Atmospher Sci & Global Change Resources, Richland, WA 99352 USA. RI Chapman, Elaine/K-8756-2012 NR 23 TC 17 Z9 17 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1999 VL 26 IS 14 BP 2183 EP 2186 DI 10.1029/1999GL900251 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 217YT UT WOS:000081527100038 ER PT J AU Rao, MV Tucker, JB Ridgway, MC Holland, OW Papanicolaou, N Mittereder, J AF Rao, MV Tucker, JB Ridgway, MC Holland, OW Papanicolaou, N Mittereder, J TI Ion-implantation in bulk semi-insulating 4H-SiC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SIC POWER DEVICES; SILICON-CARBIDE; NITROGEN; ALUMINUM; BORON AB Multiple energy N (at 500 degrees C) and Al (at 800 degrees C) ion implantations were performed into bulk semi-insulating 4H-SiC at various doses to obtain uniform implant concentrations in the range 1x10(18)-1x10(20) cm(-3) to a depth of 1.0 mu m. Implant anneals were performed at 1400, 1500, and 1600 degrees C for 15 min. For both N and Al implants, the carrier concentration measured at room temperature for implant concentrations less than or equal to 10(19) cm(-3) is limited by carrier ionization energies, whereas for the 10(20) cm(-3) implant, the carrier concentration is also limited by factors such as the solubility limit of the implanted nitrogen and residual implant damage. Lattice quality of the as-implanted and annealed material was evaluated by Rutherford backscattering spectroscopy measurements. Residual lattice damage was observed in the implanted material even after high temperature annealing. Atomic force microscopy revealed increasing deterioration in surface morphology (due to the evaporation of Si containing species) with increasing annealing temperature. The surface damage is in the form of long furrows running in one direction across the wafer to a depth of similar to 25 nm from the surface for samples annealed at 1600 degrees C for 15 min. We measured room temperature sheet resistivities of similar to 70 and 1.2x10(4) Omega/sq., respectively, for 2x10(19) cm(-3) N (1500 degrees C annealing) and 1x10(20) cm(-3) Al (1600 degrees C annealing) implanted samples. (C) 1999 American Institute of Physics. [S0021-8979(99)05914-9]. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Australian Natl Univ, Dept Mat Sci & Engn, Canberra, ACT 0200, Australia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. USN, Res Lab, Washington, DC 20375 USA. RP Rao, MV (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. RI Ridgway, Mark/D-9626-2011 OI Ridgway, Mark/0000-0002-0642-0108 NR 25 TC 43 Z9 43 U1 1 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 752 EP 758 DI 10.1063/1.370799 PG 7 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800007 ER PT J AU de Boer, MP Michalske, TA AF de Boer, MP Michalske, TA TI Accurate method for determining adhesion of cantilever beams SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MICROELECTROMECHANICAL SYSTEMS; MICROMECHANICAL STRUCTURES; FRACTAL ANALYSIS; STICTION; FILMS; POLYSILICON; SURFACES; CONTACT; GLASS AB Using surface micromachined samples, we demonstrate the accurate measurement of cantilever beam adhesion by using test structures which are adhered over long attachment lengths. We show that this configuration has a deep energy well, such that a fracture equilibrium is easily reached. When compared to the commonly used method of determining the shortest attached beam, the present method is much less sensitive to variations in surface topography or to details of capillary drying. (C) 1999 American Institute of Physics. [S0021-8979(99)00414-4]. C1 Sandia Natl Labs, Dept 1725, Albuquerque, NM 87185 USA. Sandia Natl Labs, Dept 1114, Albuquerque, NM 87185 USA. RP de Boer, MP (reprint author), Sandia Natl Labs, Dept 1725, MS 1080, Albuquerque, NM 87185 USA. RI de Boer, Maarten/C-1525-2013 OI de Boer, Maarten/0000-0003-1574-9324 NR 42 TC 165 Z9 165 U1 2 U2 21 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 817 EP 827 DI 10.1063/1.370809 PG 11 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800017 ER PT J AU Solak, HH Vladimirsky, Y Cerrina, F Lai, B Yun, W Cai, Z Ilinski, P Legnini, D Rodrigues, W AF Solak, HH Vladimirsky, Y Cerrina, F Lai, B Yun, W Cai, Z Ilinski, P Legnini, D Rodrigues, W TI Measurement of strain in Al-Cu interconnect lines with x-ray microdiffraction SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTROMIGRATION-INDUCED STRESS; CONFINED METAL LINES; PHASE ZONE-PLATE; FILMS; EVOLUTION; STATE AB We report measurement of strain in patterned Al-Cu interconnect lines with x-ray microdiffraction technique with a similar to 1 mu m spatial resolution. Monochromatized x rays from an undulator were focused on the sample using a phase fresnel zone plate and diffracted light was collected by an area detector in a symmetric, angle dispersive x-ray diffraction geometry. Measurements were made before and after the line sample was stressed for electromigration. Results show an increase in inter- and intra-grain strain variation after the testing. Differences in strain behavior of grains with (111) and (200) crystallographic planes parallel to the substrate surface were observed. A position dependent variation of strain after the testing was measured whereas no such dependence was found before the testing. (C) 1999 American Institute of Physics. [S0021-8979(99)08214-6]. C1 Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Solak, HH (reprint author), Univ Wisconsin, Dept Elect & Comp Engn, 1415 Johnson Dr, Madison, WI 53706 USA. NR 20 TC 25 Z9 26 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 884 EP 890 DI 10.1063/1.370819 PG 7 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800027 ER PT J AU Shin, NS Koo, YM Chang, CH Padmore, H AF Shin, NS Koo, YM Chang, CH Padmore, H TI Photoelectron bremsstrahlung spectrum in synchrotron radiation excited total reflection x-ray fluorescence analysis of silicon wafers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MONTE-CARLO SIMULATION; ELECTRONS; TXRF AB When synchrotron radiation is used as an excitation source, the total reflection x-ray fluorescence analysis of surface contamination on silicon wafer has an extremely low background intensity that determines the minimum detection limit. In this article, the background spectrum originating from the photoelectron bremsstrahlung is calculated using the Monte Carlo method. The doubly differential electron bremsstrahlung cross sections obtained from the Born approximation modified by the Elwert factor and with the use of the form factor approach for screening are used instead of empirical formulas. In addition to the bremsstrahlung spectrum produced from the silicon wafer, the bremsstrahlung intensity that photoelectrons, which escape from the silicon wafer, produce in the filter attached to the detector is also calculated in accordance with the usual synchrotron radiation excited total reflection x-ray fluorescence experimental conditions. The calculated photoelectron bremsstrahlung spectra are compared with experimental results and the conditions for a lower minimum detection limit are discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)01814-9]. C1 Pohang Univ Sci & Technol, Pohang 790784, South Korea. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Shin, NS (reprint author), Pohang Univ Sci & Technol, Pohang 790784, South Korea. NR 21 TC 6 Z9 6 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 902 EP 908 DI 10.1063/1.370821 PG 7 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800030 ER PT J AU Dinh, LN Schildbach, MA Balooch, M McLean, W AF Dinh, LN Schildbach, MA Balooch, M McLean, W TI Pulsed laser deposition of ZnO nanocluster films by Cu-vapor laser SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; GROWTH; ABLATION AB The dependence of stoichiometry, grain size, cathodoluminescence colors, adhesion, and surface morphology of zinc oxide films, deposited by a Cu-vapor laser at room temperature, as a function of oxygen ambient pressure during synthesis were investigated. Auger electron spectroscopy showed that ZnO films with a Zn/O ratio close to 1 were obtained at oxygen pressures > 10(-1) Torr. X-ray diffraction revealed that pulsed laser deposited zinc oxide films were composed mainly of nanocrystals, the average grain size of which grew from 5 to 17.5 nm as the oxygen pressure was increased from 10(-5) to 1 Torr. The surface morphology of the films, as determined by secondary electron microscopy, also exhibited increasing roughness as the grain size increased. Films grown in an oxygen pressure > 1.5x10(-1) Torr glowed blue under electron bombardment, while slightly substoichiometric films glowed white under similar excitation. Films deposited in an oxygen background pressure up to 1.5x10(-1) Torr exhibited good adhesion to substrates. Deposition rate on the order of 4.6 nm/s was obtained. (C) 1999 American Institute of Physics. [S0021-8979(99)06314-8]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dinh, LN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 16 TC 29 Z9 31 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 1149 EP 1152 DI 10.1063/1.370857 PG 4 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800070 ER PT J AU Davis, MJ Skodje, RT AF Davis, MJ Skodje, RT TI Geometric investigation of low-dimensional manifolds in systems approaching equilibrium SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PRINCIPAL COMPONENT ANALYSIS; STEADY-STATE APPROXIMATION; CHEMICAL-KINETICS; ENZYME-KINETICS; REACTION-MECHANISMS; GENERAL-ANALYSIS; PERTURBATION; REDUCTION; FLAMES; CONSTRUCTION AB Many systems approach equilibrium slowly along surfaces of dimension smaller than the original dimensionality. Such systems include coupled chemical kinetics and master equations. In the past the steady state approximation has been used to estimate these lower dimensional surfaces, commonly referred to as "manifolds," and thus reduce the dimensionality of the system which needs to be studied. However, the steady state approximation is often inaccurate and sometimes difficult to define unambiguously. In recent years two methods have been proposed to go beyond the steady state approximation to improve the accuracy of dimension reduction. We investigate these methods and suggest significant modifications to one of them to allow it to be used for the generation of low-dimensional manifolds in large systems. Based on the geometric investigations, two other approaches are suggested which have some advantages over these two methods for the cases studied here. All four approaches are geometric and offer advantages over methods based on the evaluation of time-dependent behavior, where phenomenological rate laws are extracted from the time-dependent behavior. (C) 1999 American Institute of Physics. [S0021-9606(99)51126-4]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Davis, MJ (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 83 TC 79 Z9 79 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 1999 VL 111 IS 3 BP 859 EP 874 DI 10.1063/1.479372 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 214CB UT WOS:000081309100010 ER PT J AU Cui, ST Cummings, PT Cochran, HD AF Cui, ST Cummings, PT Cochran, HD TI Molecular dynamics simulation of the rheological and dynamical properties of a model alkane fluid under confinement SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THIN-FILMS; EXTREME CONFINEMENT; PHASE-TRANSITIONS; SHEAR BEHAVIOR; SIMPLE LIQUIDS; BRANCHED ALKANES; N-ALKANES; TETRACOSANE; VISCOSITY; SQUALANE AB We study the effect of wall-fluid interactions on the state conditions and the effective properties of a model dodecane fluid confined between parallel solid walls. A significant increase in the effective density of the confined fluid is observed with increasing strength of the wall-fluid interaction. The effect of the wall-fluid interaction on the rotational relaxation and diffusional relaxation of the fluid is seen in the significant slowing down of the relaxation with increasing wall-fluid interaction strength. The difference between the confined fluid and the three-dimensional bulk fluid is demonstrated by the strong anisotropy of the dynamical properties, the molecular rotation, and self-diffusion. The viscosity of the confined fluid shows a large difference between weak and strong wall-fluid interactions, and a significant difference from bulk fluid at low shear rate. (C) 1999 American Institute of Physics. [S0021-9606(99)50827-1]. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Cui, ST (reprint author), Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 52 TC 34 Z9 34 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 1999 VL 111 IS 3 BP 1273 EP 1280 DI 10.1063/1.479312 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 214CB UT WOS:000081309100053 ER PT J AU Ervin, VJ Klett, JW Mundt, CM AF Ervin, VJ Klett, JW Mundt, CM TI Estimation of the thermal conductivity of composites SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID FIBER-REINFORCED COMPOSITES AB In this article we introduce the concept of homogenization for the approximation of the effective thermal conductivity of composites. A simple algebraic approximation method is proposed and shown to yield an upper bound for the effective conductivity. Numerical results are given for uni-directional carbon-carbon composites which demonstrate the validity of the approach. (C) 1999 Kluwer Academic Publishers. C1 Clemson Univ, Dept Math Sci, Clemson, SC 29634 USA. Oak Ridge Natl Lab, Carbon & Insulat Mat Technol Grp, Oak Ridge, TN 37831 USA. Clemson Univ, Dept Chem Engn, Clemson, SC 29634 USA. RP Ervin, VJ (reprint author), Clemson Univ, Dept Math Sci, Clemson, SC 29634 USA. RI Klett, James/E-6860-2017 OI Klett, James/0000-0002-2553-9649 NR 16 TC 8 Z9 9 U1 2 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JUL 15 PY 1999 VL 34 IS 14 BP 3545 EP 3553 DI 10.1023/A:1004674308487 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 217WC UT WOS:000081521100031 ER PT J AU Engelke, R Blais, NC Sander, RK AF Engelke, R Blais, NC Sander, RK TI Mass spectroscopic observation of [N3O](+) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TETRAHEDRAL N-4; NO+ AB We have observed a cation with atomic composition [N3O](+) via time-of-flight mass spectroscopy. This cation was observed in the reaction products of detonated liquid nitromethane. The same 58 amu species was observed when protonated, deuterated, and C-13-labeled nitromethane were detonated; therefore, the only possible atomic composition of the cation is [N3O](+). The existence of a metastable form of [N3O](+) has current interest since this cation is isoelectronic with electrically neutral N-4. There is interest in the metastability of N-4 structures because such species would have very high energy content and would be very powerful explosives and propellants. We present evidence that the [N3O](+) structure we observe is chemically bound. The results of ab initio quantum chemical calculations at various levels of theory are presented for three [N3O](+) structures. These calculations indicate that two of the structures are metastable and have high energy content; calculated vibrational frequencies are presented for these two forms. A lower bound on the lifetime of the observed cation is 0.52 mu s. Our results strengthen the idea that very high energy metastable forms of N-4 can exist. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Engelke, R (reprint author), Univ Calif Los Alamos Natl Lab, MS P952, Los Alamos, NM 87545 USA. NR 19 TC 12 Z9 12 U1 0 U2 0 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 JUL 15 PY 1999 VL 103 IS 28 BP 5611 EP 5614 DI 10.1021/jp990372y PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 219FX UT WOS:000081598200028 ER PT J AU Borry, RW Kim, YH Huffsmith, A Reimer, JA Iglesia, E AF Borry, RW Kim, YH Huffsmith, A Reimer, JA Iglesia, E TI Structure and density of Mo and acid sites in Mo-exchanged H-ZSM5 catalysts for nonoxidative methane conversion SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MO/HZSM-5 CATALYSTS; DEHYDROGENATION; AROMATIZATION; BENZENE; ZEOLITE; OXYGEN; HYDRATION; CATIONS; ABSENCE; HZSM-5 AB Mo/H-ZSM5 (1.0-6.3 wt % Mo; Mo/Al = 0.11-0.68) catalysts for CH4 aromatization were prepared from physical mixtures of MoO3 and H-ZSM5 (Si/Al = 14.3). X-ray diffraction and elemental analysis of physical mixtures treated in air indicate that MoOx species migrate onto the external ZSM5 surface at about 623 K. Between 773 and 973 K, MoOx species migrate inside zeolite channels via surface and gas phase transport, exchange at acid sites, and react to form H2O. The amount of H2O evolved during exchange and the amount of residual OH groups detected by isotopic equilibration with D-2 showed that each Mo atom replaces one H+ during exchange. This stoichiometry and the requirement for charge compensation suggest that exchanged species consist of (Mo2O5)(2+) ditetrahedral structures interacting with two cation exchange sites. The proposed mechanism may provide a general framework to describe the exchange of multivalent cadons onto Al sites in zeolites. As the Mo concentration exceeds that required to form a MoOx monolayer on the external zeolite surface (similar to 4 wt % Mo for the H-ZSM5 used), Mo species sublime as (MoO3), oligomers or extract Al from the zeolite framework to form inactive Al-2(MoO4)(3) domains detectable by Al-27 NMR. These (Mo2O5)(2+) species reduce to form the active MoCx species during the initial stages of CH4 conversion reactions. Optimum CH4 aromatization rates were obtained on catalysts with intermediate Mo contents (similar to 0.4 Mo/Al), because both MoCx and acid sites are required to activate CH4 and to convert the initial C2H4 products into C6+ aromatics favored by thermodynamics. C1 EO Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Iglesia, E (reprint author), EO Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017 OI Iglesia, Enrique/0000-0003-4109-1001 NR 33 TC 186 Z9 188 U1 11 U2 77 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 15 PY 1999 VL 103 IS 28 BP 5787 EP 5796 DI 10.1021/jp990866v PG 10 WC Chemistry, Physical SC Chemistry GA 219FW UT WOS:000081598100009 ER PT J AU Han, K Embury, JD Sims, JR Campbell, LJ Schneider-Muntau, HJ Pantsyrnyi, VI Shikov, A Nikulin, A Vorobieva, A AF Han, K Embury, JD Sims, JR Campbell, LJ Schneider-Muntau, HJ Pantsyrnyi, VI Shikov, A Nikulin, A Vorobieva, A TI The fabrication, properties and microstructure of Cu-Ag and Cu-Nb composite conductors SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE drawing; fibres and filaments; mechanical properties; metal matrix composite ID IN-SITU COMPOSITE; ELECTROMAGNETIC PROPERTIES; MECHANICAL-PROPERTIES; PULSED MAGNETS; HIGH-STRENGTH; WIRES; CONDUCTIVITY; ALLOY; FIELD AB The properties and the microstructure of cold-drawn Cu-Ag and Cu-Nb composites have been investigated for their potential use as conductors in pulsed high field magnets. Cu-Nb and Cu-Ag are among the leading candidates for the 100T magnet to be built in cooperation between NHMFL and LANL. These conductors show a combination of high conductivity, high strength, adequate workability, and the final section size obtainable for the wire. The conductors are operated in the temperature range from liquid nitrogen to room temperature, and therefore the mechanical and electrical properties were measured at both -196 and +25 degrees C. The 100T magnet requires conductors with various cross-sections. The conductors with small cross-sectional areas (6-12 mm(2)) require higher strength. Thus, Cu-Nb composites with cross-sectional areas between 6 and 12 mm(2) were fabricated by bundling-and-drawing and characterized. The Cu-Ag composite was developed as one of the candidates for large cross-section applications. Tt was produced by casting, forging, rolling and cold drawing to a final cross-section of up to 45 mm(2). In addition to the ability to fabricate coils for the magnet, we have considered the service life of the materials in regard to both cyclic loading and thermal fatigue. Examination of the initial portion of the stress-strain curve of cold-worked materials reveals that the internal stresses developed during the fabrication influence the mechanical response of the materials. Thus the properties of the drawn materials have been monitored as a function of cyclic loading and thermal annealing cycles. An important aspect of the selection of materials for high field magnets is the ability to obtain the material in large cross-sections and thus the work in this paper is concerned with the development of suitable production routes as well as the relationship between the structure and the properties of processed composites. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. US Natl High Magnet Field Lab, Tallahassee, FL USA. AA Bochvar All Russia Sci Res Inst Inorgan Mat, Moscow, Russia. RP Han, K (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, POB 1663,Mail Stop K765, Los Alamos, NM 87545 USA. NR 30 TC 96 Z9 126 U1 4 U2 35 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD JUL 15 PY 1999 VL 267 IS 1 BP 99 EP 114 DI 10.1016/S0921-5093(99)00025-8 PG 16 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 213VB UT WOS:000081293000011 ER PT J AU Keating, GA Layton, DW Felton, JS AF Keating, GA Layton, DW Felton, JS TI Factors determining dietary intakes of heterocyclic amines in cooked foods SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article DE heterocyclic amine; dietary intake; exposure ID FRIED BEEF PATTIES; PAN RESIDUES; VARYING DEGREES; MEAT-PRODUCTS; MODEL SYSTEM; COLON CANCER; RISK; DONENESS; TEMPERATURE; EXPOSURE AB The identification of heterocyclic amines (HCAs) in cooked foods has focused attention on the potential health effects from their consumption in the diet. Recent studies have estimated daily dietary intakes of HCAs that vary 10-fold and implicated different cooked meats as the prime source of HCAs in the diet. These varied estimates can be attributed to the different dietary assessment methods used in these studies, as well as the different levels of HCAs ascribed to the most commonly consumed cooked meats. Epidemiological studies utilizing information on dietary practice and food intake have found higher risks for several cancers among individuals consuming the highest levels of HCAs. These studies have highlighted the importance of using information on cooking methods in addition to food intake to accurately estimate dietary exposure to HCAs. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Keating, GA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, POB 808, Livermore, CA 94551 USA. FU NCI NIH HHS [CA55861] NR 29 TC 37 Z9 39 U1 0 U2 2 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 JUL 15 PY 1999 VL 443 IS 1-2 BP 149 EP 156 DI 10.1016/S1383-5742(99)00017-4 PG 8 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 221XP UT WOS:000081753100011 PM 10415438 ER PT J AU Wang, XB Wang, LS AF Wang, XB Wang, LS TI Observation of negative electron-binding energy in a molecule SO NATURE LA English DT Article ID MULTIPLY-CHARGED ANIONS; GAS-PHASE; SPECTROSCOPY; COULOMB; IONS AB In neutral atoms and molecules, electrons are kept within their orbitals by attractive electrostatic interactions with positively charged nuclei, with relatively few neutral molecules being able to bind more than one extra electron. For multiply charged molecular anions, dynamic stability plays an important role: the superposition of long-range Coulomb repulsion and short-range electron binding gives rise to a repulsive Coulomb barrier (RCB) that traps the excess electrons(1). The RCB has profound effects on the physical and chemical properties of multiply charged anions in the gas phase(1-5). For example, it has recently been shown to prevent the detachment of electrons from a doubly charged anion, even when the excitation energies exceed the electron binding energy(6,7). Here we report photodetachment experiments which demonstrate that the RCB can even trap electrons in molecular orbitals characterized by a negative binding energy. We show that the addition of sulphonate groups (-SO3-) to cyclic copper phthalocyanine (CuPc; ref. 8) systematically increases the energy of the corresponding molecular orbitals, culminating in the highest occupied molecular orbital of the tetra-anion, [CuPc(SO3)(4)](4-), being unstable by 0.9 eV. The increase in molecular orbital energy and the negative electron binding energy we observe are due to charge localization in the sulphonate groups and the resultant RCB. The unusually large height of the repulsive barrier also ensures that the anion remains metastable, and continues to store 0.9 eV excess electrostatic energy, throughout the 400 seconds we are able to observe it. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. NR 23 TC 165 Z9 165 U1 3 U2 21 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 15 PY 1999 VL 400 IS 6741 BP 245 EP 248 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 217MP UT WOS:000081503800038 ER PT J AU Patterson, FG Bonlie, J Price, D White, B AF Patterson, FG Bonlie, J Price, D White, B TI Suppression of parasitic lasing in large-aperture Ti : sapphire laser amplifiers SO OPTICS LETTERS LA English DT Article ID GENERATION; PULSES AB Transverse, parasitic lasing has been observed in several large Ti:sapphire disk amplifiers. It severely limits the signal gain and the pulse energy that can be extracted from the amplifier. We have developed a technique for suppressing these parasitic lasing modes based on index matching the crystal edges with an absorbing doped polymer thermoplastic. The parasitics are completely suppressed for the range of aperture sizes and pump fluences studied here. A comparison of the amplifier performance before and after edge cladding is presented for several Ti:sapphire crystals. (C) 1999 Optical Society of America OCIS codes: 140.3280, 140.3590, 140.3580, 030.4070, 160.5470. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Patterson, FG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 13 TC 39 Z9 45 U1 2 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUL 15 PY 1999 VL 24 IS 14 BP 963 EP 965 DI 10.1364/OL.24.000963 PG 3 WC Optics SC Optics GA 222FG UT WOS:000081772300013 PM 18073910 ER PT J AU Polian, A Grimsditch, M AF Polian, A Grimsditch, M TI High-pressure elastic properties of gallium phosphide SO PHYSICAL REVIEW B LA English DT Article ID HYDROSTATIC-PRESSURE; ULTRAHIGH PRESSURE; GAP; DEPENDENCE; CALIBRATION; TRANSITION; CONSTANTS AB The pressure dependence of the elastic constants C-ij of GaP have been measured up to 15 GPa in a diamond anvil cell. Brillouin backscattering experiments along the principal crystallographic directions yielded four combinations of elastic constants from which the three independent C-ij were extracted. Above 15 GPa the closure of the energy band gap prevents the detection of the signal. [S0163-1829(99)04827-4]. C1 Univ Paris 06, F-75252 Paris 05, France. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Polian, A (reprint author), Univ Paris 06, B77,4 Pl Jussieu, F-75252 Paris 05, France. RI Polian, Alain/E-1555-2017 OI Polian, Alain/0000-0003-2261-9114 NR 25 TC 23 Z9 23 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1468 EP 1470 DI 10.1103/PhysRevB.60.1468 PG 3 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500011 ER PT J AU Perlin, P Suski, T Ager, JW Conti, G Polian, A Christensen, NE Gorczyca, I Grzegory, I Weber, ER Haller, EE AF Perlin, P Suski, T Ager, JW Conti, G Polian, A Christensen, NE Gorczyca, I Grzegory, I Weber, ER Haller, EE TI Transverse effective charge and its pressure dependence in GaN single crystals SO PHYSICAL REVIEW B LA English DT Article ID III-V NITRIDES; HYDROSTATIC-PRESSURE; RAMAN-SCATTERING; SEMICONDUCTORS; CONSTANTS; SPECTRUM; VOLUME AB The pressure dependence of the A(1)(TO) and A(1)(LO) phonon modes of bulk, single crystals of wurtzite GaN has been measured by Raman scattering in a diamond-anvil cell up to 40 GPa. The measured phonon frequencies have been used to determine the LO and TO phonon-mode Gruneisen parameters and also the value of effective transverse charge e(T)* = 2.6 and its pressure derivative de(T)*/dP = -2.4x10(-3) GPa(-1). The experimentally obtained values are compared with results of calculations by means of tight-binding formalism combined with ab initio linear muffin-tin orbital calculations. [S0163-1829(99)05027-4]. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Polish Acad Sci, UNIPRESS, PL-01142 Warsaw, Poland. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. RP Perlin, P (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Polian, Alain/E-1555-2017; OI Polian, Alain/0000-0003-2261-9114; Ager, Joel/0000-0001-9334-9751 NR 26 TC 25 Z9 25 U1 2 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1480 EP 1483 DI 10.1103/PhysRevB.60.1480 PG 4 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500015 ER PT J AU Alsina, F Webb, JD Mascarenhas, A Geisz, JF Olson, JM Duda, A AF Alsina, F Webb, JD Mascarenhas, A Geisz, JF Olson, JM Duda, A TI Far-infrared transmission studies in disordered and ordered Ga0.52In0.48P SO PHYSICAL REVIEW B LA English DT Article ID PHONON MODES; RAMAN-SCATTERING; GAINP2; GAXIN1-XP; GA1-XINXP; SPECTRA AB The vibrational properties of both disordered and ordered Ga0.52In0.48P alloys have been studied by room-temperature polarized far-infrared transmission at normal incidence. For the disordered alloy, besides the main transverse optical mode at 332 cm(-1), we observe a weak transverse optical mode at 372 cm(-1). The transmission spectrum of the ordered alloy recorded with light polarized in the plane containing the ordering axis and the growth direction shows, in addition to the transverse modes, an extra band at 354 cm(-1). This is a signature of the reduced trigonal symmetry that we relate to a quasilongitudinal mode. [S0163-1829(99)04128-4]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Alsina, F (reprint author), Univ Autonoma Barcelona, Dept Fis, Bellaterra 08193, Spain. RI Alzina, Francesc/C-5468-2008 OI Alzina, Francesc/0000-0002-7082-0624 NR 25 TC 11 Z9 11 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1484 EP 1487 DI 10.1103/PhysRevB.60.1484 PG 4 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500016 ER PT J AU Schultz, PA AF Schultz, PA TI Local electrostatic moments and periodic boundary conditions SO PHYSICAL REVIEW B LA English DT Article ID TOTAL-ENERGY CALCULATIONS; ADSORBATE AB Electronic structure calculations frequently invoke the supercell approximation and solve for electrostatic potentials within periodic boundary conditions. For systems that are electronically charged, or contain dipole (or higher) moments, this artifice introduces spurious potentials due to interactions between the system and multipole moments of its periodic images in aperiodic directions. I describe a method to handle properly the multipole moments of the electron density in electronic structure calculations using supercells. The density is divided into two pieces. A model local density is constructed to match multipole moments of the full density. The potential from this piece is obtained treating this density as isolated. With the density of this local-moment countercharge removed from the full density, the remainder density no longer contains moments with long-range potentials, and its electrostatic potential can be evaluated accurately using periodic boundary conditions. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 73 Z9 73 U1 1 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1551 EP 1554 DI 10.1103/PhysRevB.60.1551 PG 4 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500033 ER PT J AU Bonca, J Trugman, SA Batistic, I AF Bonca, J Trugman, SA Batistic, I TI Holstein polaron SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-CRYSTAL MODEL; BIPOLARONS; ELECTRON; SYSTEMS; LIMIT AB We describe a variational method to solve the Holstein model for an electron coupled to dynamical, quantum phonons on an infinite lattice. The variational space can be systematically expanded to achieve high accuracy with modest computational resources (12-digit accuracy for the one-dimensional polaron energy at intermediate coupling). We compute ground-state and low-lying excited-state properties of the model at continuous values of the wave vector k in essentially all parameter regimes. Our results for the polaron energy band, effective mass, and correlation functions compare favorably with those of other numerical techniques, including the density-matrix renormalization-group technique, the global-local method, and the exact diagonalization technique. We find a phase transition for the first excited state between a bound and unbound system of a polaron and an additional phonon excitation. The phase transition is also treated in strong-coupling perturbation theory. C1 Univ Ljubljana, FMF, Ljubljana 1000, Slovenia. Jozef Stefan Inst, Ljubljana 1000, Slovenia. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Univ Zagreb, Inst Phys, HR-1000 Zagreb, Croatia. RP Bonca, J (reprint author), Univ Ljubljana, FMF, Ljubljana 1000, Slovenia. NR 34 TC 170 Z9 176 U1 4 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1633 EP 1642 DI 10.1103/PhysRevB.60.1633 PG 10 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500043 ER PT J AU Ferreira, LG Ozolins, V Zunger, A AF Ferreira, LG Ozolins, V Zunger, A TI Fitting of accurate interatomic pair potentials for bulk metallic alloys using unrelaxed LDA energies SO PHYSICAL REVIEW B LA English DT Article ID EMBEDDED-ATOM-METHOD; 1ST-PRINCIPLES STATISTICAL-MECHANICS; FIRST-PRINCIPLES THEORY; NI SOLID-SOLUTIONS; SHORT-RANGE ORDER; CU-AG; SEMICONDUCTOR ALLOYS; THERMODYNAMIC PROPERTIES; INTERMETALLIC COMPOUNDS; PHASE-STABILITY AB We present a general and simple method for obtaining accurate, local density approximation (LDA-) quality interatomic potentials for a large class of bulk metallic alloys. The method is based on our analysis of atomic relaxation, which reveals that the energy released in the relaxation process can be approximated by calculating the epitaxially constrained energies of the constituents A and B. Therefore, the pair potential is fitted to the LDA-calculated epitaxial energies of the constituents (to capture the relaxation energies), and to the unrelaxed energies of ordered A(n)B(m) compounds (to capture the fixed-lattice "chemical" energy). The usefulness of our approach is demonstrated by carrying out this procedure for the Cu1-xAux alloy system. The resulting pair potential reproduces the relaxed LDA formation energies of ordered compounds rather accurately, even though we used only unrelaxed energies as input. We: also predict phonon spectra of the elements and ordered compounds in very good agreement with the LDA results. From the calculations for approximate to 10 000 atom supercells representing the random alloy, we obtain the bond lengths and relaxation energies of the random phase that are not accessible to direct LDA calculations. We predict that, while in Cu-rich alloys the Cu-Cu bond is shorter than the Cu-Au bond, at higher Au compositions this order is switched. Furthermore, we find that Au-rich Cu1-xAux alloys have ground states that correspond to (001) superlattices of n monolayers of fee Au stacked on m monolayers of the L1(0) CuAu-I structure. The potential developed in this work is available at the site http://www.sst.nrel.gov/data/download.html for interested users. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Ferreira, LG (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Ozolins, Vidvuds/D-4578-2009; Zunger, Alex/A-6733-2013 NR 55 TC 17 Z9 17 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1687 EP 1696 DI 10.1103/PhysRevB.60.1687 PG 10 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500049 ER PT J AU Franceschetti, A Fu, H Wang, LW Zunger, A AF Franceschetti, A Fu, H Wang, LW Zunger, A TI Many-body pseudopotential theory of excitons in InP and CdSe quantum dots SO PHYSICAL REVIEW B LA English DT Article ID EXCHANGE INTERACTION; FINE-STRUCTURE; SEMICONDUCTORS; SILICON; SPECTROSCOPY; NANOCRYSTALLITES; CONFINEMENT; COULOMB; STATES; ENERGY AB We present a pseudopotential approach to the calculation of the excitonic spectrum of semiconductor quantum dots. Starting from a many-body expansion of the exciton wave functions in terms of single-substitution Slater determinants constructed from pseudopotential single-particle wave functions, our method permits an accurate and detailed treatment of the intraconfiguration electron-hole Coulomb and exchange interactions, while correlation effects can be included in a controlled fashion by allowing interconfiguration coupling. We calculate the exciton fine structure of InP and CdSe nanocrystals in the strong-confinement regime. We find a different size dependence for the electron-hole exchange interaction than previously assumed (i.e., R-2 instead of R-3). Our calculated exciton fine structure is compared with recent experimental results obtained by size-selective optical spectroscopies. [S0163-1829(99)00227-1]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Franceschetti, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 39 TC 260 Z9 261 U1 1 U2 36 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1819 EP 1829 DI 10.1103/PhysRevB.60.1819 PG 11 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500068 ER PT J AU Chow, W Kira, M Koch, SW AF Chow, W Kira, M Koch, SW TI Microscopic theory of optical nonlinearities and spontaneous emission lifetime in group-III nitride quantum wells SO PHYSICAL REVIEW B LA English DT Article ID GAIN; GAN; LASERS; MICROCAVITIES; ALN AB Microscopic calculations of the absorption and luminescence spectra are presented for wide bandgap Ga1-xInxN/GaN quantum well Systems. Whereas structures with narrow well widths exhibit the usual excitation-dependent bleaching of the exciton resonance without shifting spectral position, a significant blueshift of the exciton peak is obtained for wider quantum wells. This blueshift, which is also present in the excitation-dependent luminescence spectra, is attributed to the interplay between the screening of a strain induced piezoelectric field and the density dependence of many-body Coulomb effects. The calculations also show an over two orders of magnitude increase in the spontaneous electron-hole-pair lifetime with well width, due to the reduction of the electron-hole wave function overlap in the wider wells. The resulting decrease in spontaneous emission loss is predicted to lead to improved threshold properties in wide quantum well lasers. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Marburg, Dept Phys, D-35032 Marburg, Germany. Univ Marburg, Ctr Mat Sci, D-35032 Marburg, Germany. RP Chow, W (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Kira, Mackillo/G-5812-2015 NR 21 TC 60 Z9 60 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1947 EP 1952 DI 10.1103/PhysRevB.60.1947 PG 6 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500084 ER PT J AU Teeter, G Erskine, JL Shi, F Van Hove, MA AF Teeter, G Erskine, JL Shi, F Van Hove, MA TI Surface roughness and LEED crystallography: Analysis of flat and vicinal W(110) SO PHYSICAL REVIEW B LA English DT Article ID PHOTOELECTRON DIFFRACTION; MULTILAYER RELAXATION; RH(001); RH(100); METALS AB Low-energy electron diffraction intensity vs voltage (LEED I-V) measurements and analysis are used to determine the multilayer surface relaxation of W(110). Measurements and analysis are presented for both hat and vicinal surfaces, demonstrating that surface roughness leads to only small errors in LEED structure determinations. Flat, clean W(110) exhibits first-(d(12)) and second-(d(23)) layer relaxations of -3.0+/-1.3% and +0.2+/-1.3%, respectively, relative to the bulk lattice spacing d(0)=2.237 Angstrom. This experimentally determined surface relaxation of W(110) is compatible with a recent combined density-functional theory calculation and LEED study [M. Arnold, G. Hupfauer, P. Bayer, I,. Hammer, K. Heinz, B: Kohler, and M. Scheffler, Surf. Sci. 382, 288 (1997)]. Surface roughness (in the present case, uniform atomic height steps) is found to produce a small apparent increase in the measured value of d(12) when determined using standard (flat surface) LEED I-V methodology. However, for low step densities (<20 atoms/step) the apparent change in d(12) is small compared to other sources of error, so it is unlikely that surface roughness is a significant source of error in LEED structure determinations. C1 Univ Texas, Dept Phys, Austin, TX 78712 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Teeter, G (reprint author), Univ Texas, Dept Phys, Austin, TX 78712 USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 27 TC 23 Z9 23 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 3 BP 1975 EP 1981 DI 10.1103/PhysRevB.60.1975 PG 7 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500087 ER PT J AU Mo, SD Ching, WY Chisholm, MF Duscher, G AF Mo, SD Ching, WY Chisholm, MF Duscher, G TI Electronic structure of a grain-boundary model in SrTiO3 SO PHYSICAL REVIEW B LA English DT Article ID STRONTIUM-TITANATE; ELECTRICAL-CONDUCTIVITY; ATOMIC-STRUCTURE; FIRST-PRINCIPLES; DOPED SRTIO3; SPECTROSCOPY; PEROVSKITES; ALPHA-AL2O3 AB It is known that grain boundaries (GB's) in strontium titanate (SrTiO3) play an important and often a controlling role in determining the material's electrical properties. To understand how their electronic structures are related to the GB structures, we have examined two structure models of the Sigma 5 GB in SrTiO3 obtained by first-principles pseudopotential total energy calculations. The electronic structure of bulk crystal and the relaxed GB models are then studied by using the orthogonalized linear combination of atomic orbitals method. Results are presented for the ground-state structural properties and band structure of bulk SrTiO3, the total density of states (DOS), the atom and orbital-resolved partial DOS, effective charges, bond order, charge-density distribution, and near-edge structure of electron energy-loss spectroscopy. It is shown that the GB structures have smaller values of fundamental band gaps, effective charges, and bond orders relative to bulk SrTiO3. There are no GB-induced electronic states within or at the edge of the fundamental band gap. The 100-atom GB model with buckled Sr columns in the GB con is found to be a more likely model. It is also shown that the electron charge distribution across the GB line in SrTiO3 is almost balanced. C1 Univ Missouri, Dept Phys, Kansas City, MO 64110 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Mo, SD (reprint author), Univ Missouri, Dept Phys, Kansas City, MO 64110 USA. RI Ching, Wai-Yim/B-4686-2009; Duscher, Gerd/G-1730-2014 OI Ching, Wai-Yim/0000-0001-7738-8822; Duscher, Gerd/0000-0002-2039-548X NR 45 TC 80 Z9 80 U1 2 U2 30 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP 2416 EP 2424 DI 10.1103/PhysRevB.60.2416 PG 9 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400044 ER PT J AU McMahon, WE Olson, JM AF McMahon, WE Olson, JM TI Atomic-resolution study of steps and ridges on arsine-exposed vicinal Ge(100) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; MOLECULAR-BEAM EPITAXY; ANTIPHASE DOMAINS; SI(001) SURFACES; GROWTH; GAAS AB Scanning tunneling microscope images of steps on AsH3-exposed vicinal Ge(100) show very clearly that As/Ge steps reconstruct. A variety of As/Ge structures based on a "double-row" step reconstruction has been observed. We present and discuss some examples, and propose a structural model for a representative two-layer double-row As/Ge step. Under some conditions, we find that atomic-scale ridges are formed at the edges of terraces. These ridges are formed when arsine etching preferentially removes terrace atoms, leaving the steps intact. The resulting ridges are therefore simply the remnants of etch-resistant steps. An atomic-scale model for this process is proposed, and some consequences of ridge formation are discussed. [S0163-1829(99)06727-2]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP McMahon, WE (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 15 TC 22 Z9 22 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP 2480 EP 2487 DI 10.1103/PhysRevB.60.2480 PG 8 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400054 ER PT J AU Wilcoxon, JP Samara, GA Provencio, PN AF Wilcoxon, JP Samara, GA Provencio, PN TI Optical and electronic properties of Si nanoclusters synthesized in inverse micelles SO PHYSICAL REVIEW B LA English DT Article ID SILICON CLUSTERS; POROUS SILICON; QUANTUM CONFINEMENT; SURFACE-STATES; PHOTOLUMINESCENCE; SEMICONDUCTOR; LIGHT; NANOCRYSTALS; CRYSTALLITES; ABSORPTION AB Highly crystalline, size-selected silicon (Si) nanocrystals in the size range 2-10 nm were,grown in inverse micelles and their optical absorption and phoeoluminescence (PL) properties were studied. High resolution TEM and electron diffraction results show that these nanocrystals retain their cubic diamond structures down to sizes similar to 4 nm in diameter, and optical absorption data suggest that this structure and bulklike properties an retained down to the smallest sizes produced (similar to 1.8 nm diameter containing about 150 Si atoms). High pressure liquid chromatography techniques with on-line optical and electrical diagnostics were developed to purify and separate the clusters into pure, monodisperse populations. The optical absorption revealed features associated with both the indirect and direct band-gap transitions, and these transitions exhibited different quantum confinement effects. The indirect band-gap shifts from 1.1 eV in the bulk to similar to 2.1 eV for nanocrystals similar to 2 nm in diameter and the direct transition at Gamma(Gamma(25)-Gamma(15)) blueshifts by 0.4 eV from its 3.4 eV bulk value over the same size range. Tailorable, visible, room temperature PL in the range 700-350 nm (1.8-3.5 eV) was observed from these nanocrystals. The most intense PL was in the violet region of the spectrum (similar to 365 nm) and is attributed to direct electron-hole recombination. Other less intense PL peaks are attributed to surface state and to indirect band-gap recombination. The results are compared to earlier work on Si clusters grown by other techniques and to the predictions of various model calculations. Currently, the wide variations in the theoretical predictions of the various models along with considerable uncertainties in experimental size determination for clusters less than 3-4 nm, make it difficult to select among competing models. [S0163-1829(99)02328-0]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 47 TC 329 Z9 332 U1 7 U2 68 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP 2704 EP 2714 DI 10.1103/PhysRevB.60.2704 PG 11 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400080 ER PT J AU Ma, Q Rosenberg, RA AF Ma, Q Rosenberg, RA TI Interaction of Ti with the (0001) surface of highly oriented pyrolitic graphite SO PHYSICAL REVIEW B LA English DT Article ID SCANNING TUNNELING MICROSCOPY; X-RAY PHOTOEMISSION; CHEMICAL INTERACTION; SMALL CLUSTERS; AL CLUSTERS; THIN-FILMS; ALUMINUM; CARBON; 4D; FERROMAGNETISM AB The nature of the interaction between highly oriented pyrolitic graphite (HOPG) and adsorbed Ti is examined by soft x-ray photoelectron spectroscopy. By monitoring the C 1s signal, it is found that Ti does not chemically bond to, but only interacts through the Van der Waals force with, a pristine HOPG surface. Time-dependent variations in the C 1s peak intensity are interpreted in terms of diffusion of adsorbed Ti atoms, which results in the formation of clusters. This behavior is further evidence for a weakly adsorbed overlayer and implies that this surface is a priori unable to support a layer-by-layer growth. A chemical reaction occurs only when oxygen is incorporated or defects are present. The presence of adatoms on HOPG has an effect on the screening process of the HOPG C 1s core hole, which can be detected even at the Van der Waals interaction level. This may be used as a measure of the strength of interfacial interactions, especially for cases of weak or small-scale interactions. [S0163-1829(99)03728-5]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Ma, Q (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Rosenberg, Richard/K-3442-2012 NR 42 TC 25 Z9 25 U1 2 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP 2827 EP 2832 DI 10.1103/PhysRevB.60.2827 PG 6 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400092 ER PT J AU Zhang, JD Ismail Rous, PJ Baddorf, AP Plummer, EW AF Zhang, JD Ismail Rous, PJ Baddorf, AP Plummer, EW TI Periodic lattice distortion accompanying the charge-density-wave transition for Sn/Ge(111) SO PHYSICAL REVIEW B LA English DT Article ID ALPHA-PHASE; SURFACE; PB/GE(111) AB The periodic lattice distortion (PLD) accompanying the charge-density-wave (CDW) transition (at -60 degrees C) in the a phase of Sn on Ge(lll) has been determined by combining the distinct sensitivities of low-energy electron diffraction (LEED) and surface x-ray diffraction (SXRD). New LEED I-V data combined with a SXRD analysis yield a significant lattice distortion. The PLD accompanying the CDW transition is a 0.37-Angstrom vertical rippling of the Sn atoms accompanied by a perpendicular (0.17 Iq) and parallel (0.12 Angstrom) distortion of the first-layer Ge atoms, consistent with a band Jahn-Teller-like distortion. [S0163-1829(99)01128-5]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Maryland, Dept Phys, Baltimore, MD 21228 USA. RP Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Baddorf, Arthur/I-1308-2016 OI Baddorf, Arthur/0000-0001-7023-2382 NR 20 TC 43 Z9 43 U1 0 U2 11 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 JUL 15 PY 1999 VL 60 IS 4 BP 2860 EP 2863 DI 10.1103/PhysRevB.60.2860 PG 4 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400098 ER PT J AU Mauri, F Pfrommer, BG Louie, SG AF Mauri, F Pfrommer, BG Louie, SG TI Signature of surface states on NMR chemical shifts: A theoretical prediction SO PHYSICAL REVIEW B LA English DT Article ID LASER-POLARIZED XENON; CROSS-POLARIZATION; DIAMOND(111) SURFACES; PSEUDOPOTENTIALS; NUCLEI AB We show with an ab initio calculation that electronic surface states have a strong effect on NMR chemical-shift spectra. For the hydrogen-chemisorbed diamond (111) surface, we find that the atomic layers close to the surface experience a variation of the chemical shift, which is proportional to the density of empty surface states. This effect could be used as a direct probe of the surface-state density profile, by measuring experimentally the NMR chemical shift resolved for each atomic layer. [S0163-1829(99)00523-8]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Inst Romand Rech Numer Phys Mat, PPH Ecublens, CH-1015 Lausanne, Switzerland. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Mauri, F (reprint author), Univ Paris 06, LMCP, Case 115,Tour 16,4 Pl Jussieu, F-75252 Paris 05, France. RI mauri, francesco/K-5726-2012 OI mauri, francesco/0000-0002-6666-4710 NR 19 TC 21 Z9 21 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP 2941 EP 2945 DI 10.1103/PhysRevB.60.2941 PG 5 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400109 ER PT J AU Crooker, SA Rickel, DG Lyo, SK Samarth, N Awschalom, DD AF Crooker, SA Rickel, DG Lyo, SK Samarth, N Awschalom, DD TI Magnetic semiconductor quantum wells in high fields to 60 Tesla: Photoluminescence linewidth annealing at magnetization steps SO PHYSICAL REVIEW B LA English DT Article ID EXCHANGE CONSTANT; SATURATION; ALLOYS AB Magnetic semiconductors offer a unique possibility for strongly tuning the intrinsic alloy disorder potential with applied magnetic field. We report the direct observation of a series of steplike reductions in the magnetic alloy disorder potential in single ZnSe/Zn(Cd,Mn)Se quantum wells between 0 and 60 T. This disorder, measured through the linewidth of low-temperature photoluminescence spectra, drops abruptly at similar to 19, 36, and 53 T, in concert with observed magnetization steps. Conventional models of alloy disorder (developed for nonmagnetic semiconductors) reproduce the general shape of the data, but markedly underestimate the size of the linewidth reduction. [S0163-1829(99)50328-7]. C1 Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Crooker, SA (reprint author), Natl High Magnet Field Lab, MS E536, Los Alamos, NM 87545 USA. RI Samarth, Nitin/C-4475-2014 OI Samarth, Nitin/0000-0003-2599-346X NR 15 TC 38 Z9 38 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP R2173 EP R2176 DI 10.1103/PhysRevB.60.R2173 PG 4 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400011 ER PT J AU Daruka, I Barabasi, AL Zhou, SJ Germann, TC Lomdahl, PS Bishop, AR AF Daruka, I Barabasi, AL Zhou, SJ Germann, TC Lomdahl, PS Bishop, AR TI Molecular-dynamics investigation of the surface stress distribution in a Ge/Si quantum dot superlattice SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-DIFFRACTION; ASSEMBLED GE DOTS; OPTICAL-PROPERTIES; SHOCK-WAVES; SIMULATIONS; GROWTH; SILICON; GAAS AB The surface stress distribution in an ordered quantum dot superlattice is investigated using classical molecular dynamics simulations. We find that the surface stress field induced by various numbers (from 1 to 9) of Ge islands embedded in a Si(001) substrate is in good agreement with analytical expressions based on pointlike embedded force dipoles, explaining the tendency of layered arrays to form vertically aligned columns. The shea-ranged nature of this stress field implies that only the uppermost layers affect the surface growth and that their influence decreases rapidly with layer depth. [S0163-1829(99)52028-6]. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Daruka, I (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. NR 24 TC 37 Z9 37 U1 2 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP R2150 EP R2153 DI 10.1103/PhysRevB.60.R2150 PG 4 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400005 ER PT J AU Klimov, VI Schwarz, CJ McBranch, DW Leatherdale, CA Bawendi, MG AF Klimov, VI Schwarz, CJ McBranch, DW Leatherdale, CA Bawendi, MG TI Ultrafast dynamics of inter- and intraband transitions in semiconductor nanocrystals: Implications for quantum-dot lasers SO PHYSICAL REVIEW B LA English DT Article ID CARRIER RELAXATION; OPTICAL GAIN; SPECTROSCOPY; ABSORPTION; ASSIGNMENT; CLUSTERS AB Application of femtosecond transient absorption in the visible and near-IR Spectral ranges and time-resolved photoluminescence allows us to separate electron and hole relaxation paths and to map the structure bf interband and intraband optical transitions in CdSe and CdS nanocrystals (NC's) with a wide range of surface properties. In contrast to electron relaxation, which is controlled by NC surface passivation, depopulation of hole quantized states is extremely fast (sub-ps-to-ps time scales) in all types samples, independent of NC surface treatment (including NC's overcoated with a ZnS layer). Our results suggest that ultrafast hole dynamics are not due to trapping at localized surface defects such as a vacancy, but rather arise from relaxation into intrinsic NC states or intrinsically unpassivated interface states. [S0163-1829(99)51228-9]. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. MIT, Dept Chem, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RP Klimov, VI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-6,MS-J585, Los Alamos, NM 87545 USA. EM klimov@lanl.gov NR 23 TC 118 Z9 118 U1 2 U2 59 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1999 VL 60 IS 4 BP R2177 EP R2180 DI 10.1103/PhysRevB.60.R2177 PG 4 WC Physics, Condensed Matter SC Physics GA 223HA UT WOS:000081834400012 ER PT J AU Holtmann, E Kawasaki, M Kohri, K Moroi, T AF Holtmann, E Kawasaki, M Kohri, K Moroi, T TI Radiative decay of a long-lived particle and big-bang nucleosynthesis SO PHYSICAL REVIEW D LA English DT Article ID PRIMORDIAL HELIUM ABUNDANCE; HIGH DEUTERIUM ABUNDANCE; COSMOLOGICAL CONSTRAINTS; RELIC PARTICLES; LIGHT-ELEMENTS; EARLY UNIVERSE; HALO-STARS; SUPERSYMMETRY; GRAVITINOS; CRISIS AB The effects of radiatively decaying, long-lived particles on big-bang nucleosynthesis (BBN) are discussed. If high-energy photons are emitted after BBN, they may change the abundances of the light elements through photodissociation processes, which may result in a significant discrepancy between the BBN theory and observation. We calculate the abundances of the light elements, including the effects of photodissociation induced by a radiatively decaying particle, but neglecting the hadronic branching ratio. Using these calculated abundances, we derive a constraint on such particles by comparing our theoretical results with observations. Taking into account the recent controversies regarding the observations of the light-element abundances, we derive constraints for various combinations of the measurements. We also discuss several models which predict such radiatively decaying particles, and we derive constraints on such models. [S0556-2821(99)07212-4]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan. RP Holtmann, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. NR 65 TC 122 Z9 122 U1 0 U2 1 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 JUL 15 PY 1999 VL 60 IS 2 AR 023506 DI 10.1103/PhysRevD.60.023506 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 216WP UT WOS:000081467700013 ER PT J AU Hui, L Stewart, ED AF Hui, L Stewart, ED TI Superheavy dark matter from thermal inflation SO PHYSICAL REVIEW D LA English DT Article ID MEDIATED SUPERSYMMETRY-BREAKING; COSMOLOGICAL MODULI PROBLEM; DISCRETE GAUGE ANOMALIES; STANDARD MODEL; COSMIC-RAYS; PARTICLES; SCALE; BARYOGENESIS; SUPERGRAVITY; CONSTRAINT AB It is quite plausible that the mass of the dark matter particle increases significantly after its freeze-out, due to a scalar field rolling to large values. We describe a realization of this scenario in the context of thermal inflation which naturally gives a cold dark matter particle with the correct cosmological abundance and a mass around 10(10) GeV, evading the conventional upper bound of 10(5) GeV. We also discuss another realization which could produce a cosmologically interesting abundance of near Planck mass, possibly electromagnetically charged, particles. The detection and observational consequences of superheavy cold dark matter or wimpzillas are briefly examined. [S0556-2821(99)04314-3]. C1 NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Box 500, Batavia, IL 60510 USA. EM lhui@fnal.gov; ewand@fnal.gov RI Stewart, Ewan/C-1565-2011 NR 58 TC 12 Z9 12 U1 1 U2 1 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 JUL 15 PY 1999 VL 60 IS 2 AR 023518 DI 10.1103/PhysRevD.60.023518 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 216WP UT WOS:000081467700025 ER PT J AU Kaplinghat, M Scherrer, RJ Turner, MS AF Kaplinghat, M Scherrer, RJ Turner, MS TI Constraining variations in the fine-structure constant with the cosmic microwave background SO PHYSICAL REVIEW D LA English DT Article ID TIME-VARIATION; FUNDAMENTAL CONSTANTS; PHYSICAL CONSTANTS; ANISOTROPIES; NUCLEOSYNTHESIS; LIMITS AB Any time variation in the fine-structure constant alters the ionization history of the universe and therefore changes the pattern of cosmic microwave background fluctuations. We calculate the changes in the spectrum of these fluctuations as a function of the change in cu, and we find that these changes are dominated by the change in the redshift of recombination due to the shift in the binding energy of hydrogen. We estimate the accuracy with which the next generation of cosmic microwave background experiments might constrain any variation in ct at z similar to 1000. We find that such experiments could potentially be sensitive to \Delta alpha/alpha\ similar to 10(-2)-10(-3) [S0556-2821(99)02114-1]. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. RP Kaplinghat, M (reprint author), Ohio State Univ, Dept Phys, 174 W 18th Ave, Columbus, OH 43210 USA. NR 26 TC 91 Z9 91 U1 0 U2 2 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 JUL 15 PY 1999 VL 60 IS 2 AR 023516 DI 10.1103/PhysRevD.60.023516 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 216WP UT WOS:000081467700023 ER PT J AU Kolda, C March-Russell, J AF Kolda, C March-Russell, J TI Supersymmetric D-term inflation, reheating, and Affleck-Dine baryogenesis SO PHYSICAL REVIEW D LA English DT Article ID STANDARD MODEL; COSMOLOGICAL IMPLICATIONS; HYBRID INFLATION; UNIFIED THEORIES; FLAT DIRECTIONS; OPEN UNIVERSE; SITTER SPACE; SYMMETRY; SCALE; RENORMALIZATION AB The phenomenology of supersymmetric models of inflation, where the inflationary vacuum energy is dominated by D terms of a U(1), is investigated. Particular attention is paid to the questions of how to arrange for sufficient e folds of inflation to occur, what kind of thermal history is expected after the end of inflation, and how to implement successful baryogenesis. Such models are argued to require a more restrictive symmetry structure than previously thought. In particular, it is nontrivial that the decays of the fields driving D inflation can reheat the Universe in such a way as to avoid the strong gravitino production constraints. We also show how the initial conditions for Affleck-Dine baryogenesis can arise in these models and that the simplest flat directions along which a baryon number is generated can often be ruled out by the constraints coming from a decoherence of the condensate in a hot environment. At the end, we find that successful reheating and baryogenesis can take place in a large subset of D-inflationary models. [S0556-2821(99)00512-3]. C1 Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. RP Kolda, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. EM CFKolda@lbl.gov; John.March-Russell@cern.ch NR 41 TC 59 Z9 60 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 JUL 15 PY 1999 VL 60 IS 2 AR 023504 DI 10.1103/PhysRevD.60.023504 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 216WP UT WOS:000081467700011 ER PT J AU degli Atti, CC West, GB AF degli Atti, CC West, GB TI A new approach to gamma-scaling and the universal features of scaling functions and nucleon momentum distributions SO PHYSICS LETTERS B LA English DT Article ID ELASTIC ELECTRON-SCATTERING; MATTER; SYSTEMS AB Some systematic general features of y-scaling structure functions, which are essentially independent of detailed dynamics, are pointed out. Their physical interpretation in terms of general characteristics, such as a mean field description and nucleon-nucleon correlations, is given and their relationship to the momentum distributions illustrated. A new relativistic scaling variable is proposed which incorporates the momentum dependence of the excitation energy of the (A - 1) system, with the resulting scaling function being closely related to the longitudinal momentum distributions and being free from removal-energy scaling violating effects. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Perugia, Dipartimento Fis, I-06100 Perugia, Italy. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Univ Perugia, Dipartimento Fis, Via A Pascoli, I-06100 Perugia, Italy. NR 28 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUL 15 PY 1999 VL 458 IS 4 BP 447 EP 453 DI 10.1016/S0370-2693(99)00599-7 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QT UT WOS:000081563700001 ER PT J AU Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, TE Churchwell, S Court, G Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, C Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, B Reyna, D Rochester, LS Rock, SE Rondon-Aramayo, O Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, F Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B AF Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, TE Churchwell, S Court, G Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, C Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, B Reyna, D Rochester, LS Rock, SE Rondon-Aramayo, O Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, F Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B CA E155 Collaboration TI Measurement of the proton and deuteron spin structure functions g(2) and asymmetry A(2) SO PHYSICS LETTERS B LA English DT Article ID DEEP-INELASTIC-SCATTERING; NUCLEON STRUCTURE FUNCTIONS; POLARIZED STRUCTURE FUNCTIONS; STRUCTURE-FUNCTION G(1)(N); STRUCTURE-FUNCTION G1(X); SUM-RULE; PRECISION-MEASUREMENT; POWER CORRECTIONS; BAG MODEL; TARGET AB We have measured the spin structure functions g(2)(p) and g(2)(d) and the virtual photon asymmetries A(2)(p) and A(2)(d) over the kinematic range 0.02 less than or equal to x less than or equal to 0.8 and 1.0 less than or equal to Q(2) less than or equal to 30 (GeV/c)(2) by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH3 and (LiD)-Li-6 targets. The absolute value of A(2) is significantly smaller than the root R positivity limit over the measured range, while g(2) is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d(2)(p), d(2)(d) and d(2)(n). The Burkhardt-Cottingham sum rule integral integral g(2)(x)dx is reported for the range 0.02 less than or equal to x less than or equal to 0.8, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. American Univ, Washington, DC 20016 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Univ Blaise Pascal, CNRS, IN2P3, LPC, F-63170 Aubiere, France. Ruhr Univ Bochum, D-4630 Bochum, Germany. CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CEA Saclay, DAPNIA, Serv Phys Nucl, F-91191 Gif Sur Yvette, France. Florida Int Univ, Miami, FL 33199 USA. Kent State Univ, Kent, OH 44242 USA. Univ Liverpool, Liverpool L69 3BX, Merseyside, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Smith Coll, Northampton, MA 01063 USA. Stanford Univ, Stanford, CA 94305 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Anthony, PL (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Averett, Todd/A-2969-2011; Rondon Aramayo, Oscar/B-5880-2013; Frlez, Emil/B-6487-2013; Day, Donal/C-5020-2015; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015; OI Day, Donal/0000-0001-7126-8934; Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975; King, Paul/0000-0002-3448-2306; Incerti, Sebastien/0000-0002-0619-2053 NR 36 TC 85 Z9 85 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 JUL 15 PY 1999 VL 458 IS 4 BP 529 EP 535 DI 10.1016/S0370-2693(99)00590-0 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QT UT WOS:000081563700012 ER PT J AU Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, T Churchwell, S Court, GR Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, CE Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, BA Reyna, D Rochester, LS Rock, S Rondon-Aramayo, OA Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, FR Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B AF Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, T Churchwell, S Court, GR Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, CE Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, BA Reyna, D Rochester, LS Rock, S Rondon-Aramayo, OA Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, FR Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B CA E155 Collaboration TI Inclusive hadron photoproduction from longitudinally polarized protons and deuterons SO PHYSICS LETTERS B LA English DT Article ID STRUCTURE FUNCTIONS G(1); DISTRIBUTIONS; GLUON; QUARK AB We report measurements of the asymmetry A(parallel to) for inclusive hadron production on longitudinally polarized proton and deuteron targets by circularly polarized photons. The photons were produced via internal and external bremsstrahlung from an electron beam of 48.35 GeV. Asymmetries for both positive and negative signed hadrons, and a subset of identified pions, were measured in the momentum range 10 < P < 30 GeV at 2.75 degrees and 5.5 degrees. Small non-zero asymmetries are observed for the proton, while the deuteron results are consistent with zero. Recent calculations do not describe the data well. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. American Univ, Washington, DC 20016 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Univ Blaise Pascal, CNRS, IN2P3, LPC, F-63170 Aubiere, France. Ruhr Univ Bochum, D-4630 Bochum, Germany. CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CEA Saclay, DAPNIA, Serv Phys Nucl, F-91191 Gif Sur Yvette, France. Florida Int Univ, Miami, FL 33199 USA. Kent State Univ, Kent, OH 44242 USA. Univ Liverpool, Liverpool L69 3BX, Merseyside, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Smith Coll, Northampton, MA 01063 USA. Stanford Univ, Stanford, CA 94305 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Univ Wisconsin, Madison, WI 53706 USA. CNRS, IN2P3, Inst Sci Nucl, F-38026 Grenoble, France. RP Anthony, PL (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Averett, Todd/A-2969-2011; Rondon Aramayo, Oscar/B-5880-2013; Frlez, Emil/B-6487-2013; Day, Donal/C-5020-2015; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015; OI Day, Donal/0000-0001-7126-8934; Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975; Wesselmann, Frank/0000-0001-7834-7977; Hyde, Charles/0000-0001-7282-8120; King, Paul/0000-0002-3448-2306; Incerti, Sebastien/0000-0002-0619-2053 NR 23 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 JUL 15 PY 1999 VL 458 IS 4 BP 536 EP 544 DI 10.1016/S0370-2693(99)00589-4 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QT UT WOS:000081563700013 ER PT J AU Schultz, IR Merdink, JL Gonzalez-Leon, A Bull, RJ AF Schultz, IR Merdink, JL Gonzalez-Leon, A Bull, RJ TI Comparative toxicokinetics of chlorinated and brominated haloacetates in F344 rats SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article DE haloacids; metabolism; F344 rats ID DISINFECTION BY-PRODUCTS; WHOLE-EMBRYO CULTURE; MALE B6C3F1 MOUSE; DICHLOROACETIC-ACID; DRINKING-WATER; TRICHLOROACETIC-ACID; PHARMACOKINETIC MODEL; CHLORAL HYDRATE; TRICHLOROETHYLENE; METABOLISM AB Chloro, bromo, and mixed bromochloro haloacetates (HAs) are by-products of drinking water disinfection and are hepatocarcinogenic in rodents. We compared the toxicokinetics of a series of di-HAs, dichloro (DCA), bromochloro (BCA), dibromo (DBA) and tri-HAs: trichloro (TCA), bromodichloro (BDCA), chlorodibromo (CDBA), and tribromo (TBA) after iv and oral dosing (500 mu m/kg) in male F344 rats. The blood concentrations of the HAs after iv injection declined in a bi-exponential manner with a short but pronounced distributive phase. The structural features that had the greatest influence on the disposition of HAs were substitution of a halogen for a hydrogen and the degree of bromine substitution. All di-HAs had blood elimination half-lives of less than 4 h (DCA > DBA, BCA) compared to the tri-HAs, which had half-lives that varied from 0.6 to 8.0 h (TCA > BDCA > CDBA > TBA). The urinary excretion of all di-HAs was low and accounted for less than 3% of the dose in contrast to the tri-HAs, where urinary excretion accounted for at least 30% of the dose. Toxicokinetic analysis indicated the steady-state apparent volume of distribution varied between 301 and 881 ml/kg among the HAs, but the variation was not statistically significant (P > 0.17). The blood concentration-time profiles for all di-HAs after oral dosing was complex and exhibited multiple peaks. This did not appear to be due to enterohepatic recirculation, as bile duct cannulated animals also displayed similar profiles. In contrast, the profiles for the tri-HAs did not exhibit multiple peaking after oral dosing and could be described using a one-compartment pharmacokinetic model. The oral bioavailability of the HAs varied between 30% (DBA) and 116% (TCA), depending on the number of halogen substituents and the degree of bromine substitution. In general, three patterns of elimination for the HAs can be broadly described: low metabolism with moderate renal clearance (TCA), high metabolism and renal clearance (BDCA, CDBA, TBA), and high metabolism, low renal clearance (DCA, EGA, DBA). (C) 1999 Academic Press. C1 Battelle Pacific NW Natl Lab, Richland, WA 99352 USA. Washington State Univ, Pharmacol Toxicol Grad Program, Pullman, WA 99164 USA. RP Schultz, IR (reprint author), Battelle Pacific NW Natl Lab, Richland, WA 99352 USA. NR 55 TC 36 Z9 36 U1 1 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD JUL 15 PY 1999 VL 158 IS 2 BP 103 EP 114 DI 10.1006/taap.1999.8698 PG 12 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 220JJ UT WOS:000081661600003 PM 10406925 ER PT J AU Klooster, WT Koetzle, TF Siegbahn, PEM Richardson, TB Crabtree, RH AF Klooster, WT Koetzle, TF Siegbahn, PEM Richardson, TB Crabtree, RH TI Study of the N-H center dot center dot center dot H-B dihydrogen bond including the crystal structure of BH3NH3 by neutron diffraction SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID UNCONVENTIONAL HYDROGEN-BONDS; MOLECULAR-STRUCTURE; ACCEPTORS; POLYHYDRIDES; DYNAMICS; ATOMS AB Boraneamines tend to have close N-Hdelta+...delta-H-B contacts as a result of the intermolecular interaction of the NH proton with the BH bond by a novel type of hydrogen bond (the dihydrogen bond). A CSD structural search provides characteristic metric data for the interaction: the H ... H distance is in the range 1.7-2.2 Angstrom, and the N-H ... H group tends to be linear while B-H ... H tends to be bent. The reported X-ray structure of BH3NH3 seemed to provide a singular exception in having bent N-H ... H and linear B-H ... H. Our neutron diffraction structure of BH3NH3 now shows that the B and N atoms must be reversed from the assignment previously published. With the correct assignment we find the expected bent B-H ... H and linear N-H ... H arrangement in the closest intermolecular N-H ... H-B interaction (d(HH) = 2.02 Angstrom). C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Stockholm, Dept Phys, S-11385 Stockholm, Sweden. Yale Univ, Dept Chem, New Haven, CT 06520 USA. RP Klooster, WT (reprint author), Brookhaven Natl Lab, Dept Chem, POB 5000, Upton, NY 11973 USA. NR 51 TC 360 Z9 365 U1 5 U2 41 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 14 PY 1999 VL 121 IS 27 BP 6337 EP 6343 DI 10.1021/ja9825332 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 219QJ UT WOS:000081617900001 ER PT J AU McNamara, BK Yeston, JS Bergman, RG Moore, CB AF McNamara, BK Yeston, JS Bergman, RG Moore, CB TI The effect of alkane structure on rates of photoinduced C-H bond activation by Cp*Rh(CO)(2) in liquid rare gas media: An infrared flash kinetics study SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID OXIDATIVE ADDITION; SATURATED-HYDROCARBONS; IONIZATION ENERGIES; METAL-COMPLEXES; CHARGE-TRANSFER; SPECTROSCOPY; MECHANISM; RHODIUM; IR; INTERMEDIACY AB C-H bond activation via photoinduced reaction of Cp*Rh(CO)(2) (1) with alkanes (RH) in liquid Kr and liquid Xe solution has been studied by time-resolved infrared spectroscopy. Irradiation leads to the formation of a transient species absorbing at 1947 cm(-1) in liquid Kr. Reaction rates for the conversion of this species to the final C-H activation product Cp*(CO)Rh(R)(H) (4) have been measured in the -80 to -110 degrees C temperature range for a series of linear and cyclic alkanes. No reaction was observed with methane; for all other hydrocarbons, the dependence of the reaction rate on the alkane concentration follows saturation kinetics. Analysis of the kinetic data was carried out using the assumption, established in earlier work, that the observed transient is a mixture of two solvates, a krypton complex Cp*Rh(CO). Kr (2) and an alkane complex Cp*Rh(CO). RH (3), both having essentially the same CO stretching frequency in the IR. For each alkane, the rate law supports a deconvolution of the overall reaction into an alkane binding step and an oxidative addition step. For the binding step, the parameter K-eq and its associated free energy characterize a preequilibrium between 2 and 3. Within each series (linear and cyclic), as alkane size increases, the measured free energy of binding of the alkane to the coordinatively unsaturated Rh center in the Cp*Rh(CO) fragment becomes increasingly thermodynamically favorable, ranging from -0.9 (ethane) to -2.3 kcal/mol (octane) and from -2.4 (cyclopentane) to -3.5 kcal/mol (cyclooctane) at -90 degrees C relative to Kr. The second step, oxidative addition of the C-H bond across the Rh center to convert 3 to 4, proceeds with an absolute rate characterized by the parameter k(2). This rate exhibits very little variance in the series of linear alkanes. Propane, hexane, and octane each react with a rate constant of roughly (6-7) x 10(5) s(-1) at -90 degrees C, while ethane reacts about a factor of 3 more rapidly. More variance is observed in the cyclic series. Oxidative addition of cyclopentane proceeds with a rate constant of 6.8 x 10(5) s(-1) at -90 degrees C, while the oxidative addition rates of cycloheptane and cyclooctane are slower by an order of magnitude. Possible explanations are discussed for this unexpected alkane structure dependence in both steps of the reaction. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Bergman, RG (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 39 TC 52 Z9 52 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 14 PY 1999 VL 121 IS 27 BP 6437 EP 6443 DI 10.1021/ja9904282 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 219QJ UT WOS:000081617900013 ER PT J AU Demmel, JW Eisenstat, SC Gilbert, JR Li, XYS Liu, JWH AF Demmel, JW Eisenstat, SC Gilbert, JR Li, XYS Liu, JWH TI A supernodal approach to sparse partial pivoting SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE sparse matrix algorithms; unsymmetric linear systems; supernodes; column elimination tree; partial pivoting ID EXPLOITING STRUCTURAL SYMMETRY; CHOLESKY FACTORIZATION; SYMBOLIC FACTORIZATION; GAUSSIAN-ELIMINATION; MULTIFRONTAL METHOD; LINEAR-SYSTEMS; IMPLEMENTATION; EQUATIONS; ALGORITHM; DESIGN AB We investigate several ways to improve the performance of sparse LU factorization with partial pivoting, as used to solve unsymmetric linear systems. We introduce the notion of unsymmetric supernodes to perform most of the numerical computation in dense matrix kernels. We introduce unsymmetric supernode-panel updates and two-dimensional data partitioning to better exploit the memory hierarchy. We use Gilbert and Peierls's depth-first search with Eisenstat and Liu's symmetric structural reductions to speed up symbolic factorization. We have developed a sparse LU code using all these ideas. We present experiments demonstrating that it is significantly faster than earlier partial pivoting codes. We also compare its performance with UMFPACK, which uses a multifrontal approach; our code is very competitive in time and storage requirements, especially for large problems. C1 Univ Calif Berkeley, Div Comp Sci, Berkeley, CA 94720 USA. Yale Univ, Dept Comp Sci, New Haven, CT 06520 USA. Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. Xerox PARC, Palo Alto, CA USA. York Univ, Dept Comp Sci, N York, ON M3J 1P3, Canada. RP Demmel, JW (reprint author), Univ Calif Berkeley, Div Comp Sci, Berkeley, CA 94720 USA. EM demmel@cs.berkeley.edu; sce@cs.yale.edu; gilbert@xerox.com; xiaoye@nersc.gov; joseph@cs.yorku.ca NR 44 TC 370 Z9 373 U1 0 U2 6 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 13 PY 1999 VL 20 IS 3 BP 720 EP 755 DI 10.1137/S0895479895291765 PG 36 WC Mathematics, Applied SC Mathematics GA 215HE UT WOS:000081375100009 ER PT J AU Cao, XA Cho, H Pearton, SJ Dang, GT Zhang, AP Ren, F Shul, RJ Zhang, L Hickman, R Van Hove, JM AF Cao, XA Cho, H Pearton, SJ Dang, GT Zhang, AP Ren, F Shul, RJ Zhang, L Hickman, R Van Hove, JM TI Depth and thermal stability of dry etch damage in GaN Schottky diodes SO APPLIED PHYSICS LETTERS LA English DT Article ID NITRIDE; SEMICONDUCTORS; INGAN AB GaN Schottky diodes were exposed to N-2 or H-2 inductively coupled plasmas prior to deposition of the rectifying contact. Subsequent annealing, wet photochemical etching, or (NH4)(2)S surface passivation treatments were examined for their effect on diode current-voltage (I-V) characteristics. We found that either annealing at 750 degrees C under N-2, or removal of similar to 500-600 Angstrom of the surface essentially restored the initial I-V characteristics. There was no measurable improvement in the plasma-exposed diode behavior with (NH4)(2)S treatments. (C) 1999 American Institute of Physics. [S0003-6951(99)04528-3]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SVT Associates, Eden Prairie, MN 55344 USA. RP Cao, XA (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 19 TC 85 Z9 85 U1 5 U2 16 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 12 PY 1999 VL 75 IS 2 BP 232 EP 234 DI 10.1063/1.124332 PG 3 WC Physics, Applied SC Physics GA 213GW UT WOS:000081265200028 ER PT J AU Yarykin, N Cho, CR Rozgonyi, GA Zuhr, RA AF Yarykin, N Cho, CR Rozgonyi, GA Zuhr, RA TI The impact of in situ photoexcitation on the formation of vacancy-type complexes in silicon implanted at 85 and 295 K SO APPLIED PHYSICS LETTERS LA English DT Article ID ION-IMPLANTATION; BOMBARDMENT; SUPPRESSION; DEFECTS AB Photoexcitation of silicon during low-fluence implantation with MeV Si and Ge ions is observed to suppress vacancy-type point-defect formation, as determined by in situ deep-level transient spectroscopy. The A-center formation after low-temperature implantation is extended over a wide temperature interval indicating that electrically inactive clusters, which emit vacancies during annealing, are formed in the end-of-range region during implantation at 85 K. The number of vacancies stored in these clusters is influenced by low-temperature in situ photoexcitation. (C) 1999 American Institute of Physics. [S0003-6951(99)04228-X]. C1 N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Yarykin, N (reprint author), N Carolina State Univ, Dept Mat Sci & Engn, Box 7907, Raleigh, NC 27695 USA. RI Yarykn, Nikolai/C-7277-2014 NR 14 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 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 12 PY 1999 VL 75 IS 2 BP 241 EP 243 DI 10.1063/1.124335 PG 3 WC Physics, Applied SC Physics GA 213GW UT WOS:000081265200031 ER PT J AU Chow, WW Amano, H Takeuchi, T Han, J AF Chow, WW Amano, H Takeuchi, T Han, J TI Quantum-well width dependence of threshold current density in InGaN lasers SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL GAIN; SEMICONDUCTORS AB The quantum-confined Stark effect was found to result in a strong quantum-well width dependence of threshold current density in strained group-III nitride quantum well lasers. For an In0.2Ga0.8N/GaN structure with quantum-well width in the neighborhood of 3.5 nm, our analysis shows that the reduction in spontaneous emission loss by the electron-hole spatial separation outweighs the corresponding reduction in gain to produce a threshold current-density minimum. (C) 1999 American Institute of Physics. [S0003-6951(99)04328-4]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Meijo Univ, Dept Elect & Elect Engn, Tempaku Ku, Nagoya, Aichi 468, Japan. RP Chow, WW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 13 TC 26 Z9 27 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 12 PY 1999 VL 75 IS 2 BP 244 EP 246 DI 10.1063/1.124336 PG 3 WC Physics, Applied SC Physics GA 213GW UT WOS:000081265200032 ER PT J AU Park, H Lim, AKL Alivisatos, AP Park, J McEuen, PL AF Park, H Lim, AKL Alivisatos, AP Park, J McEuen, PL TI Fabrication of metallic electrodes with nanometer separation by electromigration SO APPLIED PHYSICS LETTERS LA English DT Article ID COULOMB STAIRCASE; ROOM-TEMPERATURE; TRANSPORT; NANOPARTICLES; TRANSISTOR; MOLECULES; CLUSTERS; JUNCTION; DEVICES AB A simple yet highly reproducible method to fabricate metallic electrodes with nanometer separation is presented. The fabrication is achieved by passing a large electrical current through a gold nanowire defined by electron-beam lithography and shadow evaporation. The current flow causes the electromigration of gold atoms and the eventual breakage of the nanowire. The breaking process yields two stable metallic electrodes separated by similar to 1 nm with high efficiency. These electrodes are ideally suited for electron-transport studies of chemically synthesized nanostructures, and their utility is demonstrated here by fabricating single-electron transistors based on colloidal cadmium selenide nanocrystals. (C) 1999 American Institute of Physics. [S0003-6951(99)03427-0]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Alivisatos, AP (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Park, Jiwoong/C-2327-2013; Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 25 TC 610 Z9 615 U1 13 U2 134 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 12 PY 1999 VL 75 IS 2 BP 301 EP 303 DI 10.1063/1.124354 PG 3 WC Physics, Applied SC Physics GA 213GW UT WOS:000081265200051 ER PT J AU Jacob, J Guzei, IA Espenson, JH AF Jacob, J Guzei, IA Espenson, JH TI Synthesis and structural characterization of novel terminal and bridging Re(V)-sulfido complexes SO INORGANIC CHEMISTRY LA English DT Article ID METAL SULFIDES; ALKYNES C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 14 TC 20 Z9 20 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JUL 12 PY 1999 VL 38 IS 14 BP 3266 EP 3267 DI 10.1021/ic990354v PG 2 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 217VM UT WOS:000081519600003 ER PT J AU Dorey, N Hollowood, TJ Khoze, VV Mattis, MP Vandoren, S AF Dorey, N Hollowood, TJ Khoze, VV Mattis, MP Vandoren, S TI Multi-instanton calculus and the AdS CFT correspondence in N=4 superconformal field theory SO NUCLEAR PHYSICS B LA English DT Review ID YANG-MILLS THEORY; SUPERSYMMETRIC GAUGE-THEORY; DE-SITTER-SPACE; STRING THEORY; MULTIINSTANTON CALCULUS; THEORY CORRELATORS; S-DUALITY; ADS/CFT CORRESPONDENCE; 4 DIMENSIONS; BOUND-STATES AB We present a self-contained study of ADHM multi-instantons in SU(N) gauge theory, especially the novel interplay with supersymmetry and the large-N limit. We give both field- and string-theoretic derivations of the N = 4 supersymmetric multi-instanton action and collective coordinate integration measure. As a central application, we focus on certain n-point functions G(n), n = 16, 8 or 4, in N = 4 SU(N) gauge theory at the conformal point (as well as on related higher-partial-wave correlators); these are correlators in which the 16 exact supersymmetric and superconformal fermion zero-modes are saturated. In the large-hr limit, for the first time in any four-dimensional theory, we are able to evaluate all leading-order multi-instanton contributions exactly. We find compelling evidence for Maldacena's conjecture: (1) The large-N k-instanton collective coordinate space has the geometry of a single copy of AdS(5) x S-5, (2) The integration measure on this space includes the partition function of ten-dimensional N = 1 SU(k) gauge theory dimensionally reduced to zero dimensions, matching the description of D-instantons in Type IIB string theory. (3) In exact agreement with Spe IIB string calculations, at the k-instanton level, G(n) = root N g(8) k(n-7/2) e(2 pi ik tau) Sigma(d/k) d(-2) . F-n(x(1)...,x(n)), where F-n is identical to a convolution of n bulk-to-boundary supergravity propagators. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Coll Swansea, Dept Phys, Swansea SA2 8PP, W Glam, Wales. Los Alamos Natl Lab, Theoret Div T8, Los Alamos, NM 87545 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. RP Univ Washington, Dept Phys, Seattle, WA 98195 USA. EM dorey@phys.washington.edu; pyth@schwinger.lan1.gov; valya.khoze@durham.ac.uk; mattis@lan1.gov; pysv@swan.ac.uk NR 112 TC 131 Z9 131 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD JUL 12 PY 1999 VL 552 IS 1-2 BP 88 EP 168 DI 10.1016/S0550-3213(99)00193-5 PG 81 WC Physics, Particles & Fields SC Physics GA 216FG UT WOS:000081430300004 ER PT J AU Whalen, P Kelly, K Bechtold, RL Rodgers, DE AF Whalen, P Kelly, K Bechtold, RL Rodgers, DE TI DOE documents alternative fuel success in niche markets SO OIL & GAS JOURNAL LA English DT Article C1 Natl Renewable Energy Lab, Golden, CO USA. QSS Grp Inc, Lanham, MD USA. US Dept Energy, Washington, DC USA. RP Whalen, P (reprint author), Natl Renewable Energy Lab, Golden, CO USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 USA SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD JUL 12 PY 1999 VL 97 IS 28 BP 57 EP 60 PG 4 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 217GU UT WOS:000081492300024 ER PT J AU Chen, PS Tajima, T AF Chen, PS Tajima, T TI Testing Unruh radiation with ultraintense lasers SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONS; ACCELERATION; PLASMA AB We point out that using the state-of-the-art (or soon-to-be) intense electromagnetic pulses, violent accelerations that may be suitable for testing quantum field theory in curved spacetime can be realized through the interaction of a high-intensity laser with an electron. In particular, we demonstrate that the Unruh radiation is detectable, in principle, beyond the conventional radiation (most notably the Larmor radiation) background noise, by taking advantage of its specific dependence on the laser power and distinct character in spectral-angular distributions. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Texas, Dept Phys, Austin, TX 78712 USA. RP Chen, PS (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 19 TC 115 Z9 120 U1 2 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 JUL 12 PY 1999 VL 83 IS 2 BP 256 EP 259 DI 10.1103/PhysRevLett.83.256 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900004 ER PT J AU Cullen, S Perelstein, M AF Cullen, S Perelstein, M TI SN 1987A constraints on large compact dimensions SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRINO BURST; AXIONS; SN1987A; MILLIMETER; SN-1987A AB Recently there has been a lot of interest in models in which gravity becomes strong at the TeV scale. The observed weakness of gravitational interactions is then explained by the existence of extra compact dimensions of space, which are accessible to gravity but not to standard model particles. We consider graviton emission into these extra dimensions from a hot supernova core. The phenomenology of SN 1987A places strong constraints on this energy loss mechanism, allowing us to derive a bound on the fundamental Planck scale. For the case of two extra dimensions we obtain a very strong bound of M greater than or similar to 50 TeV, which corresponds to a radius R less than or similar to 0.3 mu m. C1 Stanford Univ, Dept Phys, Stanford, CA 94309 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Cullen, S (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94309 USA. NR 26 TC 291 Z9 291 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 JUL 12 PY 1999 VL 83 IS 2 BP 268 EP 271 DI 10.1103/PhysRevLett.83.268 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900007 ER PT J AU Isgur, N AF Isgur, N TI Interpreting the neutron's electric form factor: Rest frame charge distribution or Foldy term? SO PHYSICAL REVIEW LETTERS LA English DT Article ID ZWEIG-IIZUKA RULE; CONSTITUENT-QUARK-MODEL; HYPERFINE INTERACTIONS; HADRONIC LOOPS; NUCLEON AB The neutron's electric form factor contains vital information on nucleon structure, but its interpretation within many models has been obscured by relativistic effects. I demonstrate that, to leading order in the relativistic expansion of a constituent quark model, the Foldy term cancels exactly against a contribution to the Dirac form factor F-1 to leave intact the naive interpretation of G(E)(n) as arising from the neutron's rest frame charge distribution. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Isgur, N (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 47 TC 35 Z9 35 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 JUL 12 PY 1999 VL 83 IS 2 BP 272 EP 275 DI 10.1103/PhysRevLett.83.272 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900008 ER PT J AU Takechi, M Toi, K Takagi, S Matsunaga, G Ohkuni, K Ohdachi, S Akiyama, R Darrow, DS Fujisawa, A Gotoh, M Idei, H Iguchi, H Isobe, M Kondo, T Kojima, M Kubo, S Lee, S Minami, T Morita, S Matsuoka, K Nishimura, S Okamura, S Osakabe, M Sasao, M Shimizu, M Takahashi, C Tanaka, K Yoshimura, Y AF Takechi, M Toi, K Takagi, S Matsunaga, G Ohkuni, K Ohdachi, S Akiyama, R Darrow, DS Fujisawa, A Gotoh, M Idei, H Iguchi, H Isobe, M Kondo, T Kojima, M Kubo, S Lee, S Minami, T Morita, S Matsuoka, K Nishimura, S Okamura, S Osakabe, M Sasao, M Shimizu, M Takahashi, C Tanaka, K Yoshimura, Y TI Energetic-ion-driven toroidal Alfven eigenmodes observed in a heliotron torsatron plasma SO PHYSICAL REVIEW LETTERS LA English DT Article ID FUSION TEST REACTOR; ALPHA-PARTICLES; TOKAMAK; INSTABILITIES; STELLARATOR AB Toroidal Alfven eigenmodes (TAEs) of low toroidal mode number, n = 1 and 2, an observed in neutral-beam-heated plasmas in the compact helical system heliotron/torsatron. The observed frequency is proportional to the computed TAE frequency and lies near the lower bound of the innermost TAE gap. The modes are excited only when the beam velocity exceeds about half the central Alfven velocity and when the net plasma current induced by coinjected neutral beams is in the required range. The modes are localized in the plasma core region, between 0.2 and 0.6 of the plasma minor radius. C1 Nagoya Univ, Dept Energy Engn Sci, Nagoya, Aichi 4648601, Japan. Natl Inst Fus Sci, Toki 5095292, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Grad Univ Adv Studies, Dept Fus Sci, Toki 5095292, Japan. RP Takechi, M (reprint author), Nagoya Univ, Dept Energy Engn Sci, Nagoya, Aichi 4648601, Japan. NR 23 TC 32 Z9 32 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 JUL 12 PY 1999 VL 83 IS 2 BP 312 EP 315 DI 10.1103/PhysRevLett.83.312 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900018 ER PT J AU Chin, AH Schoenlein, RW Glover, TE Balling, P Leemans, WP Shank, CV AF Chin, AH Schoenlein, RW Glover, TE Balling, P Leemans, WP Shank, CV TI Ultrafast structural dynamics in InSb probed by time-resolved x-ray diffraction SO PHYSICAL REVIEW LETTERS LA English DT Article ID 90-DEGREES THOMSON SCATTERING; LASER-PULSES; SILICON; GAAS; SURFACE; SPECTROSCOPY; PROPAGATION; PHONONS AB Ultrafast structural dynamics in laser-perturbed InSb are studied using time-resolved x-ray diffraction with a novel femtosecond x-ray source. We report the first observation of a delay in the onset of lattice expansion, which we attribute to energy relaxation processes and lattice strain propagation. In addition, we observe direct indications of ultrafast disordering on a subpicosecond time scale. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Beam Phys, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. RP Chin, AH (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Balling, Peter/D-8116-2013; Schoenlein, Robert/D-1301-2014 OI Balling, Peter/0000-0003-4955-770X; Schoenlein, Robert/0000-0002-6066-7566 NR 23 TC 151 Z9 156 U1 2 U2 25 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 JUL 12 PY 1999 VL 83 IS 2 BP 336 EP 339 DI 10.1103/PhysRevLett.83.336 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900024 ER PT J AU Majer, G Kaess, U Barnes, RG AF Majer, G Kaess, U Barnes, RG TI Model-independent measurements of hydrogen diffusivity in the lanthanum dihydride-trihydride system SO PHYSICAL REVIEW LETTERS LA English DT Article ID SWITCHABLE OPTICAL-PROPERTIES; HYDRIDE FILMS; TRANSITIONS; DIFFRACTION; LAH2-LAH3; YTTRIUM AB First model-independent measurements of the hydrogen diffusivity D in lanthanum trihydrides LaHx (2.00 less than or equal to x less than or equal to 3.0) have been performed by PFG-NMR. At a fixed concentration x less than or equal to 2.92, D(T) shows single Arrhenius behavior over wide temperature ranges. The activation enthalpy decreases with increasing x from 0.55 (x = 2.00) to 0.17 eV (x = 2.92), resulting in a strong increase in D. The formation of a hydrogen superstructure associated with the semiconductor-to-metal transition results in a strong reduction in D. It was also observed for the first time that in the stoichiometric limit D depends on the thermal history of the sample. C1 Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Majer, G (reprint author), Max Planck Inst Met Forsch, Heisenbergstr 1, D-70569 Stuttgart, Germany. NR 24 TC 13 Z9 13 U1 1 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 JUL 12 PY 1999 VL 83 IS 2 BP 340 EP 343 DI 10.1103/PhysRevLett.83.340 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900025 ER PT J AU Bulaevskii, LN Graf, MJ Maley, MP AF Bulaevskii, LN Graf, MJ Maley, MP TI Effect of an in-plane magnetic field on the interlayer transport of quasiparticles in layered superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-FERMION SUPERCONDUCTORS; T-C SUPERCONDUCTORS; ORGANIC CONDUCTORS; MAGNETORESISTANCE; SYMMETRY AB We consider the quasiparticle c-axis conductivity in highly anisotropic layered compounds in the presence of the magnetic field parallel to the layers. We show that at low temperatures the quasiparticle interlayer conductivity depends strongly on the orientation of the in-plane magnetic field if the excitation gap has nodes on the Fermi surface. Thus measurements of the angle-dependent c-axis (out-of-plane) magnetoresistance provide information on the momentum dependence of the superconducting gap (or pseudogap) on the Fermi surface. Clean and highly anisotropic layered superconductors are the best candidates for probing the existence and location of the nodes on the Fermi surface. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Bulaevskii, LN (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 14 Z9 14 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 JUL 12 PY 1999 VL 83 IS 2 BP 388 EP 391 DI 10.1103/PhysRevLett.83.388 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900037 ER PT J AU Fuhrer, MS Cherrey, K Zettl, A Cohen, ML Crespi, VH AF Fuhrer, MS Cherrey, K Zettl, A Cohen, ML Crespi, VH TI Carbon isotope effect in single-crystal Rb3C60 SO PHYSICAL REVIEW LETTERS LA English DT Article ID DOPED C-60; SUPERCONDUCTING FULLERENES; SCATTERING MECHANISMS; PALLADIUM-HYDROGEN; K3C60; RB; TEMPERATURE; RESISTIVITY; TRANSITION; SYSTEMS AB The sharp resistive transitions in superconducting single crystals of natural abundance and 99% C-13-enriched Rb3C60 reveal the carbon isotope effect with unprecedented accuracy. The measured isotope exponent alpha(C) = 0.21 +/- 0.012 is outside the error bars of all previous reported values. Our precise value for alpha(C), combined with T-c, alpha(Rb), and an ab initio calculation of the frequency distribution of the electron-phonon coupling, allows a fully constrained determination of the coupling strength lambda = 0.9(-0.1)(+0.15) and the Coulomb repulsion mu* = 0.22(-0.02)(0.03). These new measurements reveal a phonon-mediated superconductor with moderate coupling to a wide range of phonons centered near similar to 1400 K. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Penn State Univ, Dept Phys, Davey Lab 104, University Pk, PA 16802 USA. 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; Crespi, Vincent/0000-0003-3846-3193 NR 38 TC 29 Z9 29 U1 1 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 JUL 12 PY 1999 VL 83 IS 2 BP 404 EP 407 DI 10.1103/PhysRevLett.83.404 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900041 ER PT J AU Puretzky, AA Geohegan, DB Hurst, GB Buchanan, MV Luk'yanchuk, BS AF Puretzky, AA Geohegan, DB Hurst, GB Buchanan, MV Luk'yanchuk, BS TI Imaging of vapor plumes produced by matrix assisted laser desorption: A plume sharpening effect SO PHYSICAL REVIEW LETTERS LA English DT Article ID MASS-SPECTROMETRY; VELOCITY DISTRIBUTIONS AB The first gated imaging of both light matrix molecule and heavy biomolecule vapor expansion during matrix assisted laser desorption and ionization is reported, revealing a plume sharpening effect. Laser induced fluorescence imaging of dye-tagged DNase I proteins shows that these heavy molecules (30 000 Da) propagate within a very narrow angular distribution compared to that of the 3-HPA matrix (139 Da). A special solution of the gas dynamic equations is developed to describe the 3D coexpansion of heavy and light plume components. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Russian Acad Sci, Inst Gen Phys, Moscow 117942, Russia. RP Puretzky, AA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Luk`yanchuk, Boris/I-6263-2012; Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013; Buchanan, Michelle/J-1562-2016 OI Luk`yanchuk, Boris/0000-0001-8050-7212; Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139; Buchanan, Michelle/0000-0002-8078-4575 NR 11 TC 83 Z9 84 U1 0 U2 16 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 JUL 12 PY 1999 VL 83 IS 2 BP 444 EP 447 DI 10.1103/PhysRevLett.83.444 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900051 ER PT J AU Smith, S Tenenbaum, P Williams, SH AF Smith, S Tenenbaum, P Williams, SH TI Performance of the beam position monitor system of the final focus test beam SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The Beam Position Monitor (BPM) system for the Final Focus Test Beam (FFTB) at SLAG is designed to meet challenging specifications in the areas of single-pulse resolution, ab initio installation accuracy, and time-stability of BPM electrical centroids. We review the tolerances on these quantities and the technical choices made to achieve same, and detail the results of several studies of the actual performance of the system. These results are then related to the BPM system requirements for a future high-energy e(+)e(-) linear collider. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. RP Tenenbaum, P (reprint author), SLAC MS 66,Box 4349, Stanford, CA 94309 USA. 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 11 PY 1999 VL 431 IS 1-2 BP 9 EP 26 DI 10.1016/S0168-9002(99)00251-X PG 18 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 216WY UT WOS:000081468500002 ER PT J AU Engelfried, J Filimonov, I Kilmer, J Kozhevnikov, A Kubarovsky, V Molchanov, V Nemitkin, A Ramberg, E Rud, V Stutte, L AF Engelfried, J Filimonov, I Kilmer, J Kozhevnikov, A Kubarovsky, V Molchanov, V Nemitkin, A Ramberg, E Rud, V Stutte, L TI The SELEX phototube RICH detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB In this article, construction, operation, and performance of the RICH detector of Fermilab experiment 781 (SELEX) are described. The detector utilizes a matrix of 2848 phototubes for the photocathode to detect Cherenkov photons generated in a 10 m neon radiator. For the central region an N-0 of 104 cm(-1), corresponding to 13.6 hits on a beta = 1 ring, was obtained. The ring radius resolution measured is 1.6%. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Serpukhov, Russia. RP Engelfried, J (reprint author), Univ Autonoma San Luis Potosi, Inst Fis, 6 Zona Univ, San Luis Potosi 78240, Mexico. NR 12 TC 44 Z9 44 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 JUL 11 PY 1999 VL 431 IS 1-2 BP 53 EP 69 DI 10.1016/S0168-9002(99)00043-1 PG 17 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 216WY UT WOS:000081468500006 ER PT J AU Albrow, M Aota, S Apollinari, G Asakawa, T Bailey, M de Barbaro, P Barnes, V Benjamin, D Biery, K Blusk, S Bodek, A Bolla, G Breccia, L Brunetti, R Budd, H Cauz, D Demortier, L Fiori, I Frautschi, M Fukui, Y Ganel, O Gotra, Y Hahn, S Handa, T Hatakeyama, K Ikeda, H Introzzi, G Iwai, J Kikuchi, T Kim, SH Kongeter, A Kowald, W Laasanen, A Lamoureux, J Lindgren, M Liu, J Melese, P Minato, H Murgia, S Nakada, H Patrick, J Pauletta, G Sakumoto, W Santi, L Seiya, Y Solodsky, A Spiegel, L Thomas, T Vilar, R Walsh, AM Wigmans, R Zucchelli, S AF Albrow, M Aota, S Apollinari, G Asakawa, T Bailey, M de Barbaro, P Barnes, V Benjamin, D Biery, K Blusk, S Bodek, A Bolla, G Breccia, L Brunetti, R Budd, H Cauz, D Demortier, L Fiori, I Frautschi, M Fukui, Y Ganel, O Gotra, Y Hahn, S Handa, T Hatakeyama, K Ikeda, H Introzzi, G Iwai, J Kikuchi, T Kim, SH Kongeter, A Kowald, W Laasanen, A Lamoureux, J Lindgren, M Liu, J Melese, P Minato, H Murgia, S Nakada, H Patrick, J Pauletta, G Sakumoto, W Santi, L Seiya, Y Solodsky, A Spiegel, L Thomas, T Vilar, R Walsh, AM Wigmans, R Zucchelli, S TI A preshower detector for the CDF Plug Upgrade: test beam results SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID TILE FIBER SYSTEM; CALORIMETER; READOUT AB A preshower detector consisting of plastic scintillating plates with optical-fiber readout was tested at the Fermilab meson beamline. The detector was placed at a depth of about 1.5X(0), followed by an electromagnetic and hadronic calorimeter, and exposed to positron, positively charged pion and positive muon beams with energies in the range of 5-227 GeV. Multianode phototubes, HAMAMATSU R5900-M16, were used for the photon readout. The efficiency for detecting two minimum ionizing particles with noise occupancy of < 1% was 90-100% for gains of (1-4)x 10(5). It was also found that by requiring an appropriately large signal in the preshower detector, the rate of charged pions depositing a large fraction of energy in the electromagnetic calorimeter could be reduced by a factor of 1.4-2.0 (1.4-2.8) while keeping 95% (90%) efficiency for positrons. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Rockefeller Univ, New York, NY 10021 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Univ Rochester, Rochester, NY 14627 USA. Purdue Univ, W Lafayette, IN 47907 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Udine, I-33100 Udine, Italy. Ist Nazl Fis Nucl, Sez Trieste, I-33100 Udine, Italy. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. Univ Padua, Ist Nazl Fis Nucl, I-35131 Padua, Italy. Hiroshima Univ, Higashihiroshima, Hiroshima 739, Japan. Waseda Univ, Shinjuku Ku, Tokyo 169, Japan. Univ Pavia, I-27100 Pavia, Italy. Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy. Univ Karlsruhe, D-76128 Karlsruhe, Germany. Duke Univ, Durham, NC 27708 USA. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Cantabria, Santander 39009, Spain. Rutgers State Univ, Piscataway, NJ 08854 USA. RP Seiya, Y (reprint author), Fermi Natl Accelerator Lab, POB 500,MS-318, Batavia, IL 60510 USA. RI Introzzi, Gianluca/K-2497-2015 OI Introzzi, Gianluca/0000-0002-1314-2580 NR 14 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 11 PY 1999 VL 431 IS 1-2 BP 104 EP 111 DI 10.1016/S0168-9002(99)00250-8 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 216WY UT WOS:000081468500010 ER PT J AU Kurczynski, P Pehl, RH Hull, EL Palmer, D Harris, MJ Seifert, H Teegarden, BJ Gehrels, N Cline, TL Ramaty, R Sheppard, D Madden, NW Luke, PN Cork, CP Landis, DA Molone, DF Hurley, K AF Kurczynski, P Pehl, RH Hull, EL Palmer, D Harris, MJ Seifert, H Teegarden, BJ Gehrels, N Cline, TL Ramaty, R Sheppard, D Madden, NW Luke, PN Cork, CP Landis, DA Molone, DF Hurley, K TI Long-term radiation damage to a spaceborne germanium spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID FAST-NEUTRON DAMAGE; DETECTORS AB The Transient Gamma-Ray Spectrometer aboard the Wind spacecraft in deep space has observed gamma-ray bursts and solar events for four years. The germanium detector in the instrument has gradually deteriorated from exposure to the approximate to 10(8) p/cm(2)/yr( > 100 MeV) cosmic-ray flux. Low-energy tailing and loss of efficiency, attributed to hole trapping and conversion of the germanium from n- to p-type as a result of crystal damage, were observed. Raising the detector bias voltage ameliorated both difficulties and restored the spectrometer to working operation. Together, these observations extend our understanding of the effects of radiation damage to include the previously unsuccessfully studied regime of long-term operation in space. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Kurczynski, P (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 12 TC 22 Z9 22 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 JUL 11 PY 1999 VL 431 IS 1-2 BP 141 EP 147 DI 10.1016/S0168-9002(99)00283-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 216WY UT WOS:000081468500014 ER PT J AU Sperr, P Maier, MR AF Sperr, P Maier, MR TI A variable nanosecond delay for fast signals SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE nuclear electronics; nanosecond delay generator ID ENERGY AB A simple continous variable delay generator for fast signals was designed and tested in timing applications. ECL integrated circuits and fast comparators are used. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Bundeswehr Munchen, Inst Nukl Festkorperphys, D-85577 Neubiberg, Germany. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sperr, P (reprint author), Univ Bundeswehr Munchen, Inst Nukl Festkorperphys, D-85577 Neubiberg, Germany. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 11 PY 1999 VL 431 IS 1-2 BP 234 EP 235 DI 10.1016/S0168-9002(99)00240-5 PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 216WY UT WOS:000081468500024 ER PT J AU Einasto, J Einasto, M Tago, E Starobinsky, AA Atrio-Barandela, F Muller, V Knebe, A Frisch, P Cen, R Andernach, H Tucker, D AF Einasto, J Einasto, M Tago, E Starobinsky, AA Atrio-Barandela, F Muller, V Knebe, A Frisch, P Cen, R Andernach, H Tucker, D TI Steps toward the power spectrum of matter. I. The mean spectrum of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : formation; large-scale structure of universe ID SUPERCLUSTER-VOID NETWORK; CAMPANAS REDSHIFT SURVEY; LARGE-SCALE DISTRIBUTION; RICH CLUSTERS; IRAS GALAXIES; EVOLUTION; UNIVERSE; CATALOGS; SPACE; BIAS AB We calculate the mean power spectrum of all galaxies using published power spectra of galaxies and clusters of galaxies. On small scales we use the power spectrum derived from the two-dimensional distribution of Automatic Plate Measuring Facility (APM) galaxies, since this sample is not influenced by redshift distortions and is the largest and deepest sample of galaxies available. On large scales we use power spectra derived from three-dimensional data for various galaxy and cluster samples which are reduced to real space and in amplitude to the power spectrum of APM galaxies. We find that available data indicate the presence of two different populations in the nearby universe. Clusters of galaxies sample a relatively large region in the universe where rich, medium, and poor superclusters are well represented. Their mean power spectrum has a spike at wavenumber k = 0.05 +/- 0.01 h Mpc(-1), followed by an approximate power-law spectrum of index n approximate to -1.9 toward small scales. Some galaxy surveys (APM three-dimensional, IRAS QDOT, and SSRS+CfA2 130 Mpc) have similar spectra. The power spectrum found from the Las Campanas Redshift. Survey and IRAS 1.2 Jy surveys is flatter around the maximum, which may represent regions of the universe with medium-rich and poor superclusters. Differences in power spectra for these populations may partly be due to the survey geometries of the data sets in question and/or to features of the original data analysis. C1 Tartu Astrophys Observ, EE-2444 Toravere, Estonia. LD Landau Theoret Phys Inst, Moscow 117334, Russia. Univ Salamanca, E-37008 Salamanca, Spain. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Gottingen Univ Observ, D-37083 Gottingen, Germany. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. IFUG, Dept Astron, Guanajuato 36000, Mexico. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Einasto, J (reprint author), Tartu Astrophys Observ, EE-2444 Toravere, Estonia. RI Knebe, Alexander/N-1815-2014; Atrio-Barandela, Fernando/A-7379-2017; OI Knebe, Alexander/0000-0003-4066-8307; Atrio-Barandela, Fernando/0000-0002-2130-2513; Starobinsky, Alexei/0000-0002-8946-9088 NR 39 TC 21 Z9 21 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1999 VL 519 IS 2 BP 441 EP 455 DI 10.1086/307384 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213XF UT WOS:000081298000002 ER PT J AU Haiman, Z Loeb, A AF Haiman, Z Loeb, A TI Determining the redshift of reionization from the spectra of high-redshift sources SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; galaxies : formation; intergalactic medium; quasars : absorption lines; radiative transfer ID INTERGALACTIC MEDIUM; UNIVERSE; GALAXIES; METALS; QUASAR; FIELD AB The redshift at which the universe was reionized is currently unknown. We examine the optimal strategy for extracting this redshift, z(reion), from the spectra of early sources. For a source located at a redshift z(s) beyond but close to the reionization redshift, (1 + z(reion)) < (1 + z(s)) < 32/27(1 + z(reion)), the Gunn-Peterson trough splits into disjoint Ly alpha, Ly beta, and possibly higher Lyman series troughs, with some transmitted flux between these troughs. We show that although the transmitted flux is suppressed considerably by the dense Ly alpha forest at high redshifts, it could still be detectable as long as z(reion) less than or similar to 8. If the ionizing sources are bright and have a short duty cycle (e.g., if they are miniquasars or starbursts with a lifetime less than or similar to 10(6) yr), then breakthrough occurs shortly after the H II regions around them overlap, and the transmitted flux provides a measurement of z(reion). The Next Generation Space Telescope will reach the spectroscopic sensitivity required for such a measurement. C1 Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Haiman, Z (reprint author), Harvard Univ, Dept Astron, 60 Garden St, Cambridge, MA 02138 USA. NR 27 TC 48 Z9 48 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1999 VL 519 IS 2 BP 479 EP 485 DI 10.1086/307393 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213XF UT WOS:000081298000005 ER PT J AU Hui, L Gaztanaga, E AF Hui, L Gaztanaga, E TI Biased estimations of variance and skewness SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : statistics; methods : statistical ID LARGE-SCALE STRUCTURE; HIGHER-ORDER STATISTICS; APM GALAXY SURVEY; POWER-SPECTRUM; PERTURBATION-THEORY; REDSHIFT SURVEYS; COUNTS; CELLS; SIMULATIONS; MOMENTS AB Nonlinear combinations of direct observables are often used to estimate quantities of theoretical interest. Without sufficient caution, this could lead to biased estimations. An example of great interest is the skewness S-3 of the galaxy distribution, defined as the ratio of the third moment <(zeta)over bar>(3) and the variance squared <(zeta)over bar>(2)(2) smoothed at some scale R. Suppose one is given unbiased estimators for <(zeta)over bar>(3) and <(zeta)over bar>(2)(2) respectively; taking a ratio of the two does not necessarily result in an unbiased estimator of S-3. Exactly such an estimation bias (distinguished from the galaxy bias) affects most existing measurements of S-3 from galaxy surveys. Furthermore, common estimators for <(zeta)over bar>(3) and <(zeta)over bar>(2) suffer also from this kind of estimation bias themselves because of a division by the estimated mean counts in cell. In the case of <(zeta)over bar>(2), the bias is equivalent to what is commonly known as the integral constraint. We present a unifying treatment allowing all these estimation biases to be calculated analytically. These estimation biases are in general negative, and decrease in significance as the survey volume increases, for a given smoothing scale. We present a preliminary reanalysis of some existing measurements of the variance and skewness (from the APM, CfA, SSRS, and IRAS) and show that most of the well-known systematic discrepancies between surveys with similar selection criteria, but different sizes, can be attributed to the volume-dependent estimation biases. This affects the inference of the galaxy bias(es) from these surveys. Our methodology can be adapted to measurements of the variance and skewness of, for instance, the transmission distribution in quasar spectra and the convergence distribution in weak-lensing maps. We discuss generalizations to N > 3, suggest methods to reduce the estimation bias, and point out other examples in large-scale structure studies that might suffer from this type of a nonlinear estimation bias. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. CSIC, Inst Estudis Espacials Catalunya, ES-08034 Barcelona, Spain. RP Hui, L (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. OI Gaztanaga, Enrique/0000-0001-9632-0815 NR 51 TC 56 Z9 56 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1999 VL 519 IS 2 BP 622 EP 636 DI 10.1086/307401 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213XF UT WOS:000081298000019 ER PT J AU Beiersdorfer, P Lepson, JK Brown, GV Utter, SB Kahn, SM Liedahl, DA Mauche, CW AF Beiersdorfer, P Lepson, JK Brown, GV Utter, SB Kahn, SM Liedahl, DA Mauche, CW TI Observation of quasi-continuum line emission from Fe VII to Fe X in the extreme-ultraviolet region below 140 angstrom SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; stars : coronae; Sun : corona; ultraviolet : stars ID COOL STARS; EUV SPECTROSCOPY; ALPHA-CENTAURI; SPECTRUM; WAVELENGTHS; PLASMAS AB The line emission of Fe vn-Fe x ions in the extreme-ultraviolet region below 140 Angstrom was measured in controlled laboratory experiments under conditions representative of stellar coronae. The observations are compared with predictions from standard spectral models using the CHIANTI and MEKAL atomic databases. We find that the atomic databases miss most of the line flux in this region. While some of the missing lines form isolated features, most add up to form a quasi continuum in the 60-120 Angstrom region. This incompleteness can explain the poor fit when applying global-fitting techniques to spectra from cool stars measured by the Extreme-Ultraviolet Explorer satellite, the origin of which has been a source of controversy since the original observations were made. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. RP Beiersdorfer, P (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, POB 5508, Livermore, CA 94550 USA. NR 20 TC 45 Z9 47 U1 2 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1999 VL 519 IS 2 BP L185 EP L188 DI 10.1086/312122 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213XK UT WOS:000081298400020 ER PT J AU Marr, AJ Sears, TJ AF Marr, AJ Sears, TJ TI Hot band spectroscopy of DCBr near 0.96 mu m SO MOLECULAR PHYSICS LA English DT Article ID LASER EXCITATION SPECTROSCOPY; INDUCED FLUORESCENCE; SINGLET METHYLENE; PHOTOELECTRON-SPECTROSCOPY; VIBRATIONAL FREQUENCIES; SUBSTITUTED CARBENES; MAGNETIC-RESONANCE; SPECTRUM; HCF; TRANSITION AB High resolution measurements of the 2(2)(0) (bending) hot band of the (A) over tilde(1)A" <-- (X) over tilde(1)A' band system of deuterobromomethylene between 10290 cm(-1) and 10540 cm(-1) are described. The spectra were recorded by direct absorption of a continuous-wave frequency-modulated external cavity diode laser following pulsed ultraviolet laser photolysis of deuterated bromoform. Although the bending vibrational spacings in the (X) over tilde(1)A' stare are not regular, the rotational structure in its (020) level was found to be unperturbed at the accuracy of the experimental measurements. This observation provides strong evidence that the position of the excited tripler (a) over tilde(3) A", state lies to higher energy, at least 1637cm(-1) above the zero point level of the ground state. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Sears, TJ (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 47 TC 15 Z9 15 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD JUL 10 PY 1999 VL 97 IS 1-2 BP 185 EP 193 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215PN UT WOS:000081390400019 ER PT J AU Miodownik, M Godfrey, AW Holm, EA Hughes, DA AF Miodownik, M Godfrey, AW Holm, EA Hughes, DA TI On boundary misorientation distribution functions and how to incorporate them into three-dimensional models of microstructural evolution SO ACTA MATERIALIA LA English DT Article DE grain boundaries; microstructure; computer simulation ID GRAIN-GROWTH; POLYCRYSTALS; CORROSION; TEXTURE AB The fundamental difficulties of incorporating experimentally obtained boundary misorientation distributions (BMDs) into three-dimensional microstructural models are discussed. An algorithm is described which overcomes these difficulties. The boundary misorientations are treated as a statistical ensemble which is evolved toward the desired BMD using a Monte Carlo method. The application of this algorithm to a number of complex arbitrary BMDs shows that the approach is effective for both conserved and non-conserved textures. The algorithm is successfully used to create the BMDs observed in deformation microstructures containing both incidental dislocation boundaries (IDBs) and geometrically necessary boundaries (GNBs). The application of an algorithm to grain boundary engineering is discussed. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Lid. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Sandia Natl Labs, Livermore, CA USA. RP Miodownik, M (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Godfrey, Andrew/G-4458-2010; Holm, Elizabeth/S-2612-2016 OI Godfrey, Andrew/0000-0002-5496-0424; Holm, Elizabeth/0000-0003-3064-5769 NR 28 TC 61 Z9 62 U1 3 U2 12 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 JUL 9 PY 1999 VL 47 IS 9 BP 2661 EP 2668 DI 10.1016/S1359-6454(99)00137-8 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400007 ER PT J AU Zhou, SJ Preston, DL Louchet, F AF Zhou, SJ Preston, DL Louchet, F TI Investigation of vacancy formation by a jogged dissociated dislocation with large-scale molecular dynamics and dislocation energetics SO ACTA MATERIALIA LA English DT Article DE dislocations; vacancy; copper; mechanical properties; compute simulation ID EMBEDDED-ATOM METHOD; SIMULATIONS AB A series of massively parallel molecular dynamics simulations with up to 54 million atoms is performed to investigate the formation of vacancies by a moving jogged dissociated dislocation in copper at low temperatures. The jog line is formed by the intersection of two perpendicular dislocations [Zhou ei ni., Science 279, 1525 (1998)]. It is initially oriented in the [0 (1) over bar (1) over bar] direction, along which its motion is conservative, but immediately begins to deviate toward [1 (1) over bar (2) over bar]. Vacancies are formed behind the jog line either individually or in the form of tubes along [1 (1) over bar (2) over bar] or [10 (1) over bar]. The mechanism responsible for the deviation of the jog line is revealed with the help of dislocation energetics and its implication is discussed, (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. Ali rights reserved. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, MST8, Los Alamos, NM 87545 USA. UJF, INPG, UMR 5614, CNRS,LTPCM, F-38402 St Martin Dheres, France. RP Zhou, SJ (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, POB 1663, Los Alamos, NM 87545 USA. NR 18 TC 19 Z9 19 U1 1 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 JUL 9 PY 1999 VL 47 IS 9 BP 2695 EP 2703 DI 10.1016/S1359-6454(99)00127-5 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400010 ER PT J AU Sun, EY Becher, PF Hsueh, CH Painter, GS Waters, SB Hwang, SL Hoffmann, MJ AF Sun, EY Becher, PF Hsueh, CH Painter, GS Waters, SB Hwang, SL Hoffmann, MJ TI Debonding behavior between beta-Si3N4 whiskers and oxynitride glasses with or without an epitaxial beta-SiAlON interfacial layer SO ACTA MATERIALIA LA English DT Article DE structural ceramics; interface; fracture toughness; indentation ID IMPROVED FRACTURE-TOUGHNESS; SILICON-NITRIDE; MICROSTRUCTURAL DESIGN; THERMAL-EXPANSION; COMPOSITES; STRESSES; ALUMINA AB In order to gain insight on the influence of intergranular glass on the fracture toughness of silicon nitride, the debonding behavior of the interface between the prismatic faces of beta-Si3N4 whiskers and oxynitride glasses was investigated in model systems based on various Si-(Al)-Y(Ln)-O-N (Ln: rare-earth) oxynitride glasses. It was found that while the interfacial debonding strength increased when an epitaxial beta'-SiAlON layer grew on the beta-Si3N4 whiskers, the critical angle for debonding was lowered with increasing Al and O concentrations in the SiAlON layer. Only in the absence of a SiAlON epitaxial layer, were debonding conditions altered by residual stresses imposed on the interface due to thermal-mechanical mismatch. A possible explanation for the effect of SiAlON formation and its composition on the debonding behavior is suggested by first-principles atomic cluster calculations. It is concluded that by tailoring the densification additives and hence the chemistry of the intergranular glass, ii is possible to improve the fracture resistance of silicon nitride. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Univ Karlsruhe, Inst Ceram Mech Engn, Karlsruhe, Germany. RP Sun, EY (reprint author), United Technol Res Ctr, 411 Silver Lane,MS 129-26, E Hartford, CT 06108 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 30 TC 60 Z9 60 U1 1 U2 14 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 JUL 9 PY 1999 VL 47 IS 9 BP 2777 EP 2785 DI 10.1016/S1359-6454(99)00122-6 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400018 ER PT J AU Srinivasan, SG Cahn, JW Jonsson, H Kalonji, G AF Srinivasan, SG Cahn, JW Jonsson, H Kalonji, G TI Excess energy of grain-boundary trijunctions: An atomistic simulation study SO ACTA MATERIALIA LA English DT Article ID MOLECULAR-DYNAMICS; LINE TENSION AB Atomic-scale computer simulation was used to study grain-boundary trijunctions, which are defined as the intersection of three grain boundaries. The simulation system consisted of a three-dimensional periodic array of columnar f.c.c. grains having three different orientations with a common [001] direction, and in which all grains are rotated 30 degrees from their neighbors. The inter-atomic interactions were described by the Lennard-Jones potential. Each simulation cell contained six trijunctions plus the nine associated symmetric tilt grain boundaries. The energy of systems of differing sizes was monitored during annealing and after quenching to obtain quantitative estimates of the excess energy of the grain boundaries and trijunctions. For this system, the total excess energy contributed by the trijunctions was found to be negative. This result is consistent with recent calorimetry experiments on high-purity nanocrystalline cobalt conducted elsewhere. (C) 1999 Published by Elsevier Science Ltd. On behalf of Acta Metallurgica Inc. All rights reserved. C1 Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. RP Srinivasan, SG (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Jonsson, Hannes/G-2267-2013 OI Jonsson, Hannes/0000-0001-8285-5421 NR 20 TC 54 Z9 54 U1 2 U2 9 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 JUL 9 PY 1999 VL 47 IS 9 BP 2821 EP 2829 DI 10.1016/S1359-6454(99)00120-2 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400022 ER PT J AU Wang, XB Ding, CF Wang, LS AF Wang, XB Ding, CF Wang, LS TI Electron tunneling through the repulsive Coulomb barrier in photodetachment of multiply charged anions SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SPECTROSCOPY; TEMPERATURE AB There exists a repulsive Coulomb barrier for electrons in multiply charged anions. Tunneling through this barrier is expected to be important in photodetachment of MCAs. Photodetachment spectra were found to shift to lower binding energies in the tunneling regime. We present a systematic study of the tunneling effect in photodetachment experiments on a series of dianions, -O2C(CH2)(n)CO2- (n = 3-6). The observed tunneling effect and spectral shift are explained using WKB approximation based on a model potential with a square well at short range and a repulsive Coulomb potential at long range. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. NR 21 TC 71 Z9 71 U1 2 U2 11 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 JUL 9 PY 1999 VL 307 IS 5-6 BP 391 EP 396 DI 10.1016/S0009-2614(99)00543-6 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 214KC UT WOS:000081326300017 ER PT J AU Wang, HB Miller, WH AF Wang, HB Miller, WH TI Analytic continuation of real-time correlation functions to obtain thermal rate constants for chemical reaction SO CHEMICAL PHYSICS LETTERS LA English DT Article ID INITIAL-VALUE REPRESENTATION; MECHANICAL RATE CONSTANTS; REACTION PROBABILITY; NUMERICAL TEST; DYNAMICS; APPROXIMATION; PROPAGATION; SYSTEMS AB It is shown how a particular correlation function, computed quantum mechanically or semiclassically as a function of real-time, can be analytically continued to obtain thermal rate constants (or other thermally averaged quantities) over a wide range of temperature. The correlation function is first evaluated at a reference temperature, and then analytically continued to obtain information at other desired temperatures. The method is applied to the calculation of the thermal rate constant for the Cl + H-2 --> HCl + H (J = 0) reaction using the flux correlation function formalism, and it is seen to be capable of obtaining accurate rate constants over a broad temperature range. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Miller, WH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Wang, Haobin/E-1208-2011 NR 30 TC 3 Z9 3 U1 0 U2 1 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 JUL 9 PY 1999 VL 307 IS 5-6 BP 463 EP 468 DI 10.1016/S0009-2614(99)00546-1 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 214KC UT WOS:000081326300027 ER PT J AU Erzberger, JP Wilson, DM AF Erzberger, JP Wilson, DM TI The role of Mg2+ and specific amino acid residues in the catalytic reaction of the major human abasic endonuclease: New insights from EDTA-resistant incision of acyclic abasic site analogs and site-directed mutagenesis SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE DNA repair; Ape1; Hap1; nuclease; phosphate hydrolysis ID HUMAN APURINIC ENDONUCLEASE; BASE EXCISION-REPAIR; DNA-REPAIR; EXONUCLEASE-III; APYRIMIDINIC ENDONUCLEASE; ACTIVE-SITE; MECHANISM; PROTEIN; HAP1; APE AB Ape1, the major protein responsible for excising apurinic/apyrimidinic (AP) sites from DNA, cleaves 5' to natural AP sites via a hydrolytic reaction involving Mg2+. We report here that while Ape1 incision of the AP site analog tetrahydrofuran (F-DNA) was similar to 7300-fold reduced in 4 mM EDTA relative to Mg2+, cleavage of ethane (E-DNA) and propane (P-DNA) acyclic abasic site analogs was only 20 and 30-fold lower, respectively, in EDTA compared to Mg2+. This finding suggests that the primary role of the metal ion is to promote a conformational change in the ring-containing abasic DNA, priming it for enzyme-mediated hydrolysis. Mutating the proposed metal-coordinating residue E96 to A or Q resulted in a similar to 600-fold reduced incision activity for both P and F-DNA in Mg2+ compared to wild-type. These mutants, while retaining full binding activity for acyclic P-DNA, were unable to incise this substrate in EDTA, pointing to an alternative or an additional function for E96 besides Mg2+-coordination. Other residues proposed to be involved in metal coordination were mutated (D70A, D70R, D308A and D308S), but displayed a relatively minor loss of incision activity for F and P-DNA in Mg2+, indicating a non-essential function for these amino acid residues. Mutations at Y171 resulted in a 5000-fold reduced incision activity. A Y171H mutant was fourfold less active than a Y171F mutant, providing evidence that Y171 does not operate as the proton donor in catalysis and that the additional role of E96 may be in establishing the appropriate active site environment via a hydrogen-bonding network involving Y171. D210A and D210N mutant proteins exhibited a similar to 25,000-fold reduced incision activity, indicating a critical role for this residue in the catalytic reaction. A D210H mutant was 15 to 20-fold more active than the mutants D210A or D210N, establishing that D210 likely operates as the leaving group proton donor. (C) 1999 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Livermore, CA 94551 USA. RP Wilson, DM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, POB 808,L-452, Livermore, CA 94551 USA. FU NCI NIH HHS [CA79056] NR 34 TC 77 Z9 79 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUL 9 PY 1999 VL 290 IS 2 BP 447 EP 457 DI 10.1006/jmbi.1999.2888 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 218BP UT WOS:000081533600008 PM 10390343 ER PT J AU Thompson, MJ Eisenberg, D AF Thompson, MJ Eisenberg, D TI Transproteomic evidence of a loop-deletion mechanism for enhancing protein thermostability SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE thermophiles; genomics; proteome; surface loops ID COMPLETE GENOME SEQUENCE; THERMAL-STABILITY; CRYSTAL-STRUCTURE; THERMOTOGA-MARITIMA; BACILLUS-STEAROTHERMOPHILUS; PYROCOCCUS-FURIOSUS; ESCHERICHIA-COLI; CITRATE SYNTHASE; ARCHAEON; DEHYDROGENASE AB Understanding the molecular determinants of protein thermostability is of theoretical and practical importance. While numerous determinants have been suggested, no molecular feature has been judged of paramount importance, with the possible exception of ion-pair networks. The difficulty in identifying the main determinants may have been the limited structural information available on the thermostable proteins. Recently the complete genomes for mesophilic, thermophilic and hyperthermophilic organisms have been sequenced, vastly improving the potential for uncovering general trends in sequence and structure evolution related to thermostability and, thus, for isolating the more important determinants. From a comparative analysis of 20 complete genomes, we find a trend towards shortened thermophilic proteins relative to their mesophilic homologs. Moreover, sequence alignments to proteins of known structure indicate that thermophilic sequences are more likely than their mesophilic homologs to have deletions in exposed loop regions. The new genomes offer enough comparable sequences to compute meaningful statistics that point to loop deletion as a general evolutionary strategy for increasing thermostability. (C) 1999 Academic Press. C1 Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Box 951570, Los Angeles, CA 90095 USA. NR 54 TC 190 Z9 198 U1 0 U2 10 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUL 9 PY 1999 VL 290 IS 2 BP 595 EP 604 DI 10.1006/jmbi.1999.2889 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 218BP UT WOS:000081533600021 PM 10390356 ER PT J AU Merdink, JL Stenner, RD Stevens, DK Parker, JC Bull, RJ AF Merdink, JL Stenner, RD Stevens, DK Parker, JC Bull, RJ TI Effect of enterohepatic circulation on the pharmacokinetics of chloral hydrate and its metabolites in F344 rats SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH-PART A LA English DT Article ID DICHLOROACETIC ACID; B6C3F1 MICE; TRICHLOROACETIC-ACID; SPECIES-DIFFERENCES; MOUSE-LIVER; MONOCARBOXYLIC ACIDS; RAS PROTOONCOGENE; PROXIMAL TUBULE; TRICHLOROETHYLENE; HEPATOCARCINOGENICITY AB Chloral hydrate (CH) is a commonly found disinfection by-product in water purification, a metabolite of trichloroethylene, arid a sedative/hypnotic drug. CH and two of its reported metabolites, trichloroacetic acid (TCA) and dichloroacetic acid (DCA), are hepatocarcinogenic in mice. Another metabolite of CH, trichloroethanol (TCE), is also metabolized into TCA, and the enterohepatic circulation (EHC) of TCE maintains a pool of metabolite for the eventual production of TCA. To gain insight on the effects of EHC on the kinetics of CH and on the formation of TCA and DCA, dual cannulated F344 rats were infused with 12, 48, or 192 mg/kg of CH and the blood, bile, urine, and feces were collected over a 48-h period. CH was cleared rapidly (>3000 ml/h/kg) and displayed biphasic elimination kinetics, with the first phase being elimination of the dose and the second phase exhibiting formation rate-limited kinetics relative to its TCE metabolite. The effects of EHC on metabolite kinetics were only significant at the highest dose, resulting in a 44% and 17% decease in the area under the curve (AUC) of TCA and TCE, respectively. The renal clearance of CH, free TCE (f-TCE), and TCA of 2, 2.7, and 38 ml/h/kg, respectively, indicates an efficient reabsorption mechanism for all of these small chlorinated compounds. DCA was detected at only trace levels (<2 mu M) as a metabolite of CH, TCA, or TCE. C1 Pacific NW Lab, Richland, WA 99352 USA. Washington State Univ, Grad Program Pharmacol Toxicol, Pullman, WA 99164 USA. Washington State Univ, Coll Pharm, Pullman, WA 99164 USA. US EPA, Washington, DC 20460 USA. RP Merdink, JL (reprint author), Pacific NW Lab, POB 999 P7-56, Richland, WA 99352 USA. NR 21 TC 4 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0098-4108 J9 J TOXICOL ENV HEAL A JI J. TOXICOL. ENV. HEALTH PT A PD JUL 9 PY 1999 VL 57 IS 5 BP 357 EP 368 DI 10.1080/009841099157665 PG 12 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 210TK UT WOS:000081120600004 PM 10405189 ER PT J AU Ng, EG Pierce, DJ AF Ng, EG Pierce, DJ TI Special section on sparse and structured matrices and their applications SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Editorial Material C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Boeing Co, Seattle, WA 98124 USA. RP Ng, EG (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 9 PY 1999 VL 20 IS 4 BP 887 EP 887 PG 1 WC Mathematics, Applied SC Mathematics GA 222WJ UT WOS:000081808100004 ER PT J AU Ng, EG Raghavan, P AF Ng, EG Raghavan, P TI Performance of greedy ordering heuristics for sparse Cholesky factorization SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE sparse matrix ordering; minimum degree; minimum deficiency; greedy heuristics ID MINIMUM-DEGREE ALGORITHM; ELIMINATION AB Greedy algorithms for ordering sparse matrices for Cholesky factorization can be based on different metrics. Minimum degree, a popular and effective greedy ordering scheme, minimizes the number of nonzero entries in the rank-1 update (degree) at each step of the factorization. Alternatively, minimum deficiency minimizes the number of nonzero entries introduced (deficiency) at each step of the factorization. In this paper we develop two new heuristics: modified minimum deficiency (MMDF) and modified multiple minimum degree (MMMD). The former uses a metric similar to deficiency while the latter uses a degree-like metric. Our experiments reveal that on the average, MMDF orderings result in 21% fewer operations to factor than minimum degree; MMMD orderings result in 15% fewer operations to factor than minimum degree. MMMD requires on the average 7-13% more time than minimum degree, while MMDF requires on the average 33-34% more time than minimum degree. C1 Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. RP Ng, EG (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. NR 24 TC 18 Z9 19 U1 1 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 9 PY 1999 VL 20 IS 4 BP 902 EP 914 DI 10.1137/S0895479897319313 PG 13 WC Mathematics, Applied SC Mathematics GA 222WJ UT WOS:000081808100006 ER PT J AU Demmel, JW Gilbert, JR Li, XYS AF Demmel, JW Gilbert, JR Li, XYS TI An asynchronous parallel supernodal algorithm for sparse Gaussian elimination SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE sparse Gaussian elimination; unsymmetric linear systems; supernodes; parallelism; dynamic scheduling and load balancing ID EXPLOITING STRUCTURAL SYMMETRY; LINEAR ALGEBRA SUBPROGRAMS; CHOLESKY FACTORIZATION; SYMBOLIC FACTORIZATION; IMPLEMENTATION; SET AB Although Gaussian elimination with partial pivoting is a robust algorithm to solve unsymmetric sparse linear systems of equations, it is difficult to implement efficiently on parallel machines because of its dynamic and somewhat unpredictable way of generating work and intermediate results at run time. In this paper, we present an efficient parallel algorithm that overcomes this difficulty. The high performance of our algorithm is achieved through (1) using a graph reduction technique and a supernode-panel computational kernel for high single processor utilization, and (2) scheduling two types of parallel tasks for a high level of concurrency. One such task is factoring the independent panels in the disjoint subtrees of the column elimination tree of A. Another task is updating a panel by previously computed supernodes. A scheduler assigns tasks to free processors dynamically and facilitates the smooth transition between the two types of parallel tasks. No global synchronization is used in the algorithm. The algorithm is well suited for shared memory machines (SMP) with a modest number of processors. We demonstrate 4- to 7-fold speedups on a range of 8 processor SMPs, and more on larger SMPs. One realistic problem arising from a 3-D flow calculation achieves factorization rates of 1.0, 2.5, 0.8, and 0.8 gigaflops on the 12 processor Power Challenge, 8 processor Cray C90, 16 processor Cray J90, and 8 processor AlphaServer 8400. C1 Univ Calif Berkeley, Div Comp Sci, Berkeley, CA 94720 USA. Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp, Berkeley, CA 94720 USA. RP Demmel, JW (reprint author), Univ Calif Berkeley, Div Comp Sci, Berkeley, CA 94720 USA. EM demmel@cs.berkeley.edu; gilbert@parc.xerox.com; xiaoye@nersc.gov NR 34 TC 113 Z9 113 U1 0 U2 5 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 9 PY 1999 VL 20 IS 4 BP 915 EP 952 DI 10.1137/S0895479897317685 PG 38 WC Mathematics, Applied SC Mathematics GA 222WJ UT WOS:000081808100007 ER PT J AU Bai, ZJ Day, D Ye, Q AF Bai, ZJ Day, D Ye, Q TI ABLE: An adaptive block Lanczos method for non-Hermitian eigenvalue problems SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE non-Hermitian matrices; eigenvalue problem; spectral transformation; Lanczos method ID SPARSE UNSYMMETRIC MATRICES; ARNOLDI METHOD; ALGORITHM; EIGENPROBLEMS; ITERATION; SUBSPACE; ERROR AB This work presents an adaptive block Lanczos method for large-scale non-Hermitian Eigenvalue problems (henceforth the ABLE method). The ABLE method is a block version of the non-Hermitian Lanczos algorithm. There are three innovations. First, an adaptive blocksize scheme cures (near) breakdown and adapts the blocksize to the order of multiple or clustered eigenvalues. Second, stopping criteria are developed that exploit the semiquadratic convergence property of the method. Third, a well-known technique from the Hermitian Lanczos algorithm is generalized to monitor the loss of biorthogonality and maintain semibiorthogonality among the computed Lanczos vectors. Each innovation is theoretically justified. Academic model problems and real application problems are solved to demonstrate the numerical behaviors of the method. C1 Univ Kentucky, Dept Math, Lexington, KY 40506 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Manitoba, Dept Appl Math, Winnipeg, MB R3T 2N2, Canada. RP Univ Kentucky, Dept Math, Lexington, KY 40506 USA. EM bai@ms.uky.edu; dday@cs.sandia.gov; ye@gauss.amath.umanitoba.ca NR 52 TC 44 Z9 44 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 EI 1095-7162 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 9 PY 1999 VL 20 IS 4 BP 1060 EP 1082 DI 10.1137/S0895479897317806 PG 23 WC Mathematics, Applied SC Mathematics GA 222WJ UT WOS:000081808100014 ER PT J AU Geist, GA Howell, GW Watkins, DS AF Geist, GA Howell, GW Watkins, DS TI The BR eigenvalue algorithm SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE eigenvalue computation; QR algorithm; unsymmetric Lanczos process ID UNSYMMETRIC LANCZOS PROCESS; COMPLETED THEORY; MATRICES AB The BR algorithm, a new method for calculating the eigenvalues of an upper Hessenberg matrix, is introduced. It is a bulge-chasing algorithm like the QR algorithm, but, unlike the QR algorithm, it is well adapted to computing the eigenvalues of the narrow-band, nearly tridiagonal matrices generated by the look-ahead Lanczos process. This paper describes the BR algorithm and gives numerical evidence that it works well in conjunction with the Lanczos process. On the biggest problems run so far, the BR algorithm beats the QR algorithm by a factor of 30-60 in computing time and a factor of over 100 in matrix storage space. C1 Oak Ridge Natl Lab, Math Sci Sect, Oak Ridge, TN 37831 USA. Florida Inst Technol, Dept Appl Math, Melbourne, FL 32901 USA. Washington State Univ, Dept Pure & Appl Math, Pullman, WA 99164 USA. RP Geist, GA (reprint author), 6835 24th Ave NE, Seattle, WA 98115 USA. NR 19 TC 8 Z9 9 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JUL 9 PY 1999 VL 20 IS 4 BP 1083 EP 1098 DI 10.1137/S0895479897317077 PG 16 WC Mathematics, Applied SC Mathematics GA 222WJ UT WOS:000081808100015 ER PT J AU Pelhos, K Hannon, JB Kellogg, GL Madey, TE AF Pelhos, K Hannon, JB Kellogg, GL Madey, TE TI LEEM investigation of the faceting of the Pt covered W(111) surface SO SURFACE SCIENCE LA English DT Article DE faceting; growth; low-energy electron microscopy (LEEM); nucleation; platinum; surface diffusion; tungsten ID ENERGY-ELECTRON-MICROSCOPY; ULTRATHIN METAL-FILMS; GROWTH; SI(001); ISLANDS; RECONSTRUCTION; MOBILITIES; NUCLEATION; MORPHOLOGY; REACTIVITY AB A low energy electron microscope has been used to investigate the faceting of W(111) as induced by Pt. The atomically rough W(111) surface, when fully covered with a monolayer film of Pt and annealed to temperatures higher than similar to 750 K, experiences a significant morphological restructuring: the initially planar surface undergoes a faceting transition and forms three-sided pyramids with {211} faces. The experiments demonstrate the capability of low energy electron microscopy for imaging both the fully and the partially faceted surface. In addition, we have observed the formation of the facets in real time, when Pt is dosed onto the heated surface. We find that the transition from planar surface, to partially faceted surface, and to fully faceted surface proceeds through the nucleation and growth of spatially separated faceted regions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Rutgers State Univ, Surface Modificat Lab, Piscataway, NJ 08854 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Madey, TE (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08854 USA. EM madey@physics.rutgers.edu NR 37 TC 17 Z9 17 U1 3 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL 9 PY 1999 VL 432 IS 1-2 BP 115 EP 124 DI 10.1016/S0039-6028(99)00543-9 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 218TA UT WOS:000081566700014 ER PT J AU Rustad, JR Wasserman, E Felmy, AR AF Rustad, JR Wasserman, E Felmy, AR TI A molecular dynamics investigation of surface reconstruction on magnetite (001) SO SURFACE SCIENCE LA English DT Letter DE energy minimization; Fe3O4; iron oxide; magnetite; molecular dynamics; surface energy; surface relaxation; surface structure ID SCANNING-TUNNELING-MICROSCOPY; BEAM EPITAXY; STATICS CALCULATIONS; FE3O4; GROWTH; FILMS AB Molecular dynamics calculations using analytical potential functions with polarizable oxygen ions have been used to identify a novel mode of reconstruction on the half-occupied tetrahedral layer termination of the magnetite (Fe3O4) (001) surface. In the proposed reconstruction, the twofold coordinated iron ion in the top monolayer rotates downward to occupy a vacant half-octahedral site in the plane of the second-layer iron ions. At the same time, half of the tetrahedral iron ions in the third iron layer are pushed upward to occupy an adjacent octahedral vacancy at the level of the second-layer iron ions. The other half of the third-layer iron ions remain roughly in their original positions The proposed reconstruction is consistent with recent low-energy electron diffraction and X-ray photoelectron spectroscopy results. It also provides a compelling interpretation for the arrangement of atoms suggested by high-resolution scanning-tunneling microscopy studies. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Rustad, JR (reprint author), Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. NR 17 TC 31 Z9 31 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL 9 PY 1999 VL 432 IS 1-2 BP L583 EP L588 DI 10.1016/S0039-6028(99)00581-6 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 218TA UT WOS:000081566700001 ER PT J AU Dahl, DA Appelhans, AD Ward, MB AF Dahl, DA Appelhans, AD Ward, MB TI A univoltage ion gun design SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion optics; ion guns; secondary ion mass spectrometry AB A broad beam ion gun has been designed and tested that requires only a single high voltage supply. It creates 1-2-mm-diameter 2-10 kV beams that are visually uniform in spatial intensity with a sharp edge cutoff using a Perrhenate solid state ion source. The gun's electrode geometry is designed to make beam diameter independent of acceleration voltage. Moreover, the source is imaged at the focal length of the acceleration optics to obtain a beam with visually uniform spatial intensity. With this approach, all points on the source's emission surface contribute equally to the brightness of each point in the beam. The univoltage ion gun design has demonstrated its utility in broad beam static secondary ionization mass spectrometry (SIMS) instruments and is being adopted as the ion gun of choice for many of our group's instruments. (C) 1999 Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Dahl, DA (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 6 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD JUL 8 PY 1999 VL 189 IS 1 BP 39 EP 46 DI 10.1016/S1387-3806(99)00050-0 PG 8 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 212XB UT WOS:000081242000005 ER PT J AU Dahl, DA Appelhans, AD Ward, MB AF Dahl, DA Appelhans, AD Ward, MB TI A modular ion beam deflector SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion optics; secondary ion mass spectrometry; ion trap AB A modular electrostatic ion beam deflector has been designed and tested that provides well-isolated xy deflection with minimal beam distortion using a single supply voltage per deflector stage. The convenient stacked electrode design of these deflectors facilitates precise assembly while providing good field termination and isolation characteristics. (C) 1999 Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Dahl, DA (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 3 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD JUL 8 PY 1999 VL 189 IS 1 BP 47 EP 51 DI 10.1016/S1387-3806(99)00051-2 PG 5 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 212XB UT WOS:000081242000006 ER PT J AU Ratsep, M Blankenship, RE Small, GJ AF Ratsep, M Blankenship, RE Small, GJ TI Energy transfer and spectral dynamics of the three lowest energy Q(y)-states of the Fenna-Matthews-Olson antenna complex SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID EXCITON LEVEL STRUCTURE; STEADY-STATE SPECTRA; PROSTHECOCHLORIS-AESTUARII; BACTERIOCHLOROPHYLL PROTEIN; INTEGRAL INTERPRETATION; DISPERSIVE KINETICS; CHLOROBIUM-TEPIDUM; POLYVINYL-ALCOHOL; LOW-TEMPERATURES; PHOTOSYSTEM-II AB Temperature-dependent (1.8-10 K) spectral hole burning results are presented for the three lowest Q(y)-states of the Fenna-Matthews-Olson (FMO) bacteriochlorophyll a antenna complex of Chlorobium tepidum that contribute to the 825 nm absorption band. Both holewidth and hole growth kinetic data are presented. The data indicate that the three states he at 823, 825, and 827 nm and, furthermore, that they are associated with the lowest energy state of the subunit of the FMO trimer; Structural heterogeneity results in the three states being energetically inequivalent. The time constants for downward energy transfer from the 823 and 825 nm states are 37 and 117 ps, respectively. It is argued that the time constants for the 823 nm --> 825 and 823 nm --> 827 nm pathways are 117 and 54 ps, respectively. The dispersive hole growth kinetic data for the three states obtained at 1.8 and 8.0 K are shown to be consistent with the excited-state lifetimes and homogeneous widths of the zero-phonon absorption lines. Analysis of the data leads to a lifetime of 2 ns for. the 827 nm state. The temperature dependencies of the zero-phonon lines associated with this and the other two states are identical and characteristic of coupling to the two-level systems of the protein. C1 Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Arizona State Univ, Dept Chem & Biochem, Tempe, AZ 85287 USA. RP Small, GJ (reprint author), Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. NR 32 TC 31 Z9 32 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 8 PY 1999 VL 103 IS 27 BP 5736 EP 5741 DI 10.1021/jp990918g PG 6 WC Chemistry, Physical SC Chemistry GA 216ZG UT WOS:000081473900016 ER PT J AU Butcher, EA AF Butcher, EA TI Clearance effects on bilinear normal mode frequencies SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID LINEAR-SYSTEMS; OSCILLATOR AB The effects of a clearance or interference on the normal mode frequencies of a n-dof system with bilinear stiffness and without damping are investigated through various modifications of the bilinear frequency relation. First, the exact penetration distances and bilinear natural frequencies of a single-degree-of-freedom system are analytically obtained in terms of the amount of clearance and the strength of non-linearity, and an equivalent linear system is derived. These results are in turn used to construct three methods which approximate the bilinear frequencies for the n-dof system. The specific example of a two-dof system is studied in which the resulting approximate frequencies are compared with those obtained from numerical simulations in order to determine the most accurate approximation technique. The results demonstrate how these bilinear normal mode frequencies vary with the magnitude of the clearance/interference and thus point toward the need of including such effects in methods which utilize the bilinear frequency relation. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Butcher, EA (reprint author), Univ Alaska, Dept Engn Mech, Fairbanks, AK 99775 USA. NR 14 TC 32 Z9 32 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUL 8 PY 1999 VL 224 IS 2 BP 305 EP 328 DI 10.1006/jsvi.1999.2168 PG 24 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 214UX UT WOS:000081346900007 ER PT J AU Cornwell, P Doebling, SW Farrar, CR AF Cornwell, P Doebling, SW Farrar, CR TI Application of the strain energy damage detection method to platelike structures SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB In this paper the problem of using measured modal parameters to detect and locate damage in plate-like structures is investigated. Many methods exist for locating damage in a structure given the modal properties before and after damage. Unfortunately, many of these methods require a correlated finite element model or mass normalized mode shapes. If the modal properties are obtained using ambient excitation then the mode shapes will not be mass normalized. In this paper a method based on the changes in the strain energy of the structure will be discussed. This method was originally developed for beam-like structures, that is, structures characterized by one-dimensional curvature. In this paper the method will be generalized to plate-like structures that are characterized by two-dimensional curvature. This method only requires the mode shapes of the structure before and after damage. To evaluate the effectiveness of the method it will be applied to both simulated and experimental data. (C) 1999 Academic Press. C1 Rose Hulman Inst Technol, Terre Haute, IN 47805 USA. Univ Calif Los Alamos Natl Lab, ESA EA, Los Alamos, NM 87545 USA. RP Cornwell, P (reprint author), Rose Hulman Inst Technol, 5500 Wabash Ave, Terre Haute, IN 47805 USA. RI Farrar, Charles/C-6954-2012 NR 12 TC 200 Z9 219 U1 1 U2 8 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUL 8 PY 1999 VL 224 IS 2 BP 359 EP 374 DI 10.1006/jsvi.1999.2163 PG 16 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 214UX UT WOS:000081346900010 ER PT J AU Boggild, H Boissevain, J Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Fields, DE Franz, A Hansen, KH Holzer, EB Humanic, TJ Jacak, BV Jayanti, R Kalechofsky, H Lee, YY Leltchouk, M Lorstad, B Maeda, N Martin, L Medvedev, A Miyabayashi, A Murray, M Nishimura, S Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Sakaguchi, A Sarabura, M Schmidt-Sorensen, J Spegel, M Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y van Hecke, H Willis, WJ Wolf, K Xu, N AF Boggild, H Boissevain, J Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Fields, DE Franz, A Hansen, KH Holzer, EB Humanic, TJ Jacak, BV Jayanti, R Kalechofsky, H Lee, YY Leltchouk, M Lorstad, B Maeda, N Martin, L Medvedev, A Miyabayashi, A Murray, M Nishimura, S Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Sakaguchi, A Sarabura, M Schmidt-Sorensen, J Spegel, M Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y van Hecke, H Willis, WJ Wolf, K Xu, N CA NA44 Collaboration TI Two-proton correlations near midrapidity in p+Pb and S+Pb collisions at the CERN SPS SO PHYSICS LETTERS B LA English DT Article DE two-proton correlations; proton-nucleus; nucleus-nucleus; heavy-ion collisions; proton source size; CERN SPS ID HEAVY-ION COLLISIONS; NUCLEAR COLLISIONS; ULTRARELATIVISTIC ENERGIES; 2-PARTICLE CORRELATIONS; INTERFEROMETRY; DEPENDENCE; DISTRIBUTIONS; AU-197; GEV/C AB Correlations of two protons emitted near midrapidity in p + Pb collisions at 450 GeV/c and S + Pb collisions at 200 A GeV/c are presented, as measured by the NA44 Experiment. The correlation effect, which arises as a result of final state interactions and Fermi-Dirac statistics, is related to the space-time characteristics of proton emission. The measured source sizes are smaller than the size of the target lead nucleus but larger than the sizes of the projectiles. A dependence on the collision centrality is observed; the source size increases with decreasing impact parameter. Proton source sizes near midrapidity appear to be smaller than those of pions in the same interactions. Quantitative agreement with the results of RQMD (v1.08) simulations is found for p + Pb collisions. For S + Pb collisions the measured correlation effect is somewhat weaker than that predicted by the model simulations, implying either a larger source size or larger contribution of protons from long-lived particle decays. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. SUBATECH, F-44070 Nantes, France. Columbia Univ, New York, NY 10027 USA. Hiroshima Univ, Higashihiroshima 724, Japan. CERN, CH-1211 Geneva 23, Switzerland. Ohio State Univ, Columbus, OH 43210 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Univ Lund, S-22362 Lund, Sweden. Texas A&M Univ, College Stn, TX 77843 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Warsaw Univ Technol, PL-00662 Warsaw, Poland. RP Boggild, H (reprint author), Niels Bohr Inst, Blegdamsvej 17, DK-2100 Copenhagen, Denmark. NR 28 TC 13 Z9 13 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 JUL 8 PY 1999 VL 458 IS 2-3 BP 181 EP 189 DI 10.1016/S0370-2693(99)00614-0 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QQ UT WOS:000081563500002 ER PT J AU Kolda, C Lyth, DH AF Kolda, C Lyth, DH TI Quintessential difficulties SO PHYSICS LETTERS B LA English DT Article ID COSMOLOGICAL CONSTANT; GOLDSTONE BOSONS; MODELS AB An alternative to a cosmological constant is quintessence, defined as a slowly-varying scalar field potential V(phi). If quintessence is observationally significant, an epoch of inflation is beginning at the present epoch, with phi the slowly-rolling inflaton field. In contrast with ordinary inflation, quintessence seems to require extreme fine tuning of the potential V(phi). The degree of fine-tuning is quantified in various cases. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Lancaster, Dept Phys, Lancaster LA1 4YB, England. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. NR 24 TC 127 Z9 127 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUL 8 PY 1999 VL 458 IS 2-3 BP 197 EP 201 DI 10.1016/S0370-2693(99)00657-7 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QQ UT WOS:000081563500004 ER PT J AU Aggarwal, MM Agnihotri, A Ahammed, Z Angelis, ALS Antonenko, V Arefiev, V Astakhov, V Avdeitchikov, V Awes, TC Baba, PVKS Badyal, SK Baldine, A Barabach, L Barlag, C Bathe, S Batiounia, B Bernier, T Bhalla, KB Bhatia, VS Blume, C Bock, R Bohne, EM Borocz, Z Bucher, D Buijs, A Busching, H Carlen, L Chalyshev, V Chattopadhyay, S Cherbatchev, R Chujo, T Claussen, A Das, AC Decowski, MP Djordjadze, V Donni, P Doubovik, I Dutt, S Majumdar, MRD El Chenawi, K Eliseev, S Enosawa, K Foka, P Fokin, S Frolov, V Ganti, MS Garpman, S Gavrishchuk, O Geurts, FJM Ghosh, TK Glasow, R Gupta, SK Guskov, B Gustafsson, HA Gutbrod, HH Higuchi, R Hrivnacova, I Ippolitov, M Kalechofsky, H Kamermans, R Kampert, KH Karadjev, K Karpio, K Kato, S Kees, S Kim, H Kolb, BW Kosarev, I Koutcheryaev, I Krumpel, T Kugler, A Kulinich, P Kurata, M Kurita, K Kuzmin, N Langbein, I Lebedev, A Lee, YY Lohner, H Luquin, L Mahapatra, DP Manko, V Martin, M Maximov, A Mehdiyev, R Mgebrichvili, G Miake, Y Mikhalev, D Mir, MF Mishra, GC Miyamoto, Y Morrison, D Mukhopadhyay, DS Myalkovski, V Naef, H Nandi, BK Nayak, SK Nayak, TK Neumaier, S Nianine, A Nikitine, V Nikolaev, S Nilsson, P Nishimura, S Nomokonov, P Nystrand, J Obenshain, FE Oskarsson, A Otterlund, I Pachr, M Parfenov, A Pavliouk, S Peitzmann, T Petracek, V Plasil, F Pinanaud, W Purschke, ML Raeven, B Rak, J Raniwala, R Raniwala, S Ramamurthy, VS Rao, NK Retiere, F Reygers, K Roland, G Rosselet, L Roufanov, I Roy, C Rubio, JM Sako, H Sambyal, SS Santo, R Sato, S Schlagheck, H Schmidt, HR Shabratova, G Shah, TH Sibiriak, I Siemiarczuk, T Silvermyr, D Sinha, BC Slavine, N Soderstrom, K Solomey, N Sorensen, SP Stankus, P Stefanek, G Steinberg, P Stenlund, E Stuken, D Sumbera, M Svensson, T Trivedi, MD Tsvetkov, A Twenhofel, C Tykarski, L Urbahn, J Von Eijndhoven, N Von Nieuwenhuizen, GJ Vinogradov, A Viyogi, YP Vodopianov, A Voros, S Wyslouch, B Yagi, K Yokota, Y Young, GR AF Aggarwal, MM Agnihotri, A Ahammed, Z Angelis, ALS Antonenko, V Arefiev, V Astakhov, V Avdeitchikov, V Awes, TC Baba, PVKS Badyal, SK Baldine, A Barabach, L Barlag, C Bathe, S Batiounia, B Bernier, T Bhalla, KB Bhatia, VS Blume, C Bock, R Bohne, EM Borocz, Z Bucher, D Buijs, A Busching, H Carlen, L Chalyshev, V Chattopadhyay, S Cherbatchev, R Chujo, T Claussen, A Das, AC Decowski, MP Djordjadze, V Donni, P Doubovik, I Dutt, S Majumdar, MRD El Chenawi, K Eliseev, S Enosawa, K Foka, P Fokin, S Frolov, V Ganti, MS Garpman, S Gavrishchuk, O Geurts, FJM Ghosh, TK Glasow, R Gupta, SK Guskov, B Gustafsson, HA Gutbrod, HH Higuchi, R Hrivnacova, I Ippolitov, M Kalechofsky, H Kamermans, R Kampert, KH Karadjev, K Karpio, K Kato, S Kees, S Kim, H Kolb, BW Kosarev, I Koutcheryaev, I Krumpel, T Kugler, A Kulinich, P Kurata, M Kurita, K Kuzmin, N Langbein, I Lebedev, A Lee, YY Lohner, H Luquin, L Mahapatra, DP Manko, V Martin, M Maximov, A Mehdiyev, R Mgebrichvili, G Miake, Y Mikhalev, D Mir, MF Mishra, GC Miyamoto, Y Morrison, D Mukhopadhyay, DS Myalkovski, V Naef, H Nandi, BK Nayak, SK Nayak, TK Neumaier, S Nianine, A Nikitine, V Nikolaev, S Nilsson, P Nishimura, S Nomokonov, P Nystrand, J Obenshain, FE Oskarsson, A Otterlund, I Pachr, M Parfenov, A Pavliouk, S Peitzmann, T Petracek, V Plasil, F Pinanaud, W Purschke, ML Raeven, B Rak, J Raniwala, R Raniwala, S Ramamurthy, VS Rao, NK Retiere, F Reygers, K Roland, G Rosselet, L Roufanov, I Roy, C Rubio, JM Sako, H Sambyal, SS Santo, R Sato, S Schlagheck, H Schmidt, HR Shabratova, G Shah, TH Sibiriak, I Siemiarczuk, T Silvermyr, D Sinha, BC Slavine, N Soderstrom, K Solomey, N Sorensen, SP Stankus, P Stefanek, G Steinberg, P Stenlund, E Stuken, D Sumbera, M Svensson, T Trivedi, MD Tsvetkov, A Twenhofel, C Tykarski, L Urbahn, J Von Eijndhoven, N Von Nieuwenhuizen, GJ Vinogradov, A Viyogi, YP Vodopianov, A Voros, S Wyslouch, B Yagi, K Yokota, Y Young, GR CA WA98 Collaboration TI Systematics of inclusive photon production in 158 center dot A GeVPb induced reactions on Ni, Nb, and Pb targets SO PHYSICS LETTERS B LA English DT Article ID TRANSVERSE-MOMENTUM DISTRIBUTIONS; PHASE-TRANSITION; HADRONIC-INTERACTIONS; NUCLEAR COLLISIONS; S+AU COLLISIONS; MULTIPLICITY; DEPENDENCE; ENERGIES; AGEV; CERN AB The multiplicity of inclusive photons has been measured on an event-by-event basis for 158.A GeV Pb induced reactions on Ni, Nb, and Pb targets. The systematics of the pseudorapidity densities at midrapidity (rho(max)) and the width of the pseudorapidity distributions have been studied for varying centralities for these collisions. A power law fit to the photon yield as a function of the number of participating nucleons gives a value of 1.12 +/- 0.03 for the exponent. The mean transverse momentum, [p(T)], of photons determined from the ratio of the measured electromagnetic transverse energy and photon multiplicity, remains almost constant with increasing rho(max). Results are compared with model predictions. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Panjab Univ, Chandigarh 160014, India. Univ Rajasthan, Jaipur 302004, Rajasthan, India. Ctr Variable Energy Cyclotron, Calcutta 700064, W Bengal, India. Univ Geneva, CH-1211 Geneva 4, Switzerland. Kurchatov Inst, RRC, RU-123182 Moscow, Russia. Joint Inst Nucl Res, RU-141980 Dubna, Russia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Jammu, Jammu 180001, India. Univ Munster, D-48149 Munster, Germany. Ecole Mines, SUBATECH, Nantes, France. Gesell Schwerionenforsch GmbH, D-64220 Darmstadt, Germany. Univ Utrecht, NIKHEF, NL-3508 TA Utrecht, Netherlands. Univ Lund, SE-22100 Lund, Sweden. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Inst Nucl Phys, CZ-25068 Rez, Czech Republic. Univ Groningen, KVI, NL-9747 AA Groningen, Netherlands. Inst Nucl Studies, PL-00681 Warsaw, Poland. MIT, Cambridge, MA 02139 USA. Inst Phys, Bhubaneswar 751005, Orissa, India. Univ Tennessee, Knoxville, TN 37966 USA. RP Aggarwal, MM (reprint author), Panjab Univ, Chandigarh 160014, India. RI Decowski, Patrick/A-4341-2011; Peitzmann, Thomas/K-2206-2012; Mehdiyev, Rashid/H-6299-2013; Lohner, Herbert/B-2397-2014; Sumbera, Michal/O-7497-2014 OI Peitzmann, Thomas/0000-0002-7116-899X; Lohner, Herbert/0000-0002-7441-739X; Sumbera, Michal/0000-0002-0639-7323 NR 37 TC 29 Z9 29 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 JUL 8 PY 1999 VL 458 IS 2-3 BP 422 EP 430 DI 10.1016/S0370-2693(99)00560-2 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 218QQ UT WOS:000081563500035 ER PT J AU Dietz, ML Bond, AH Hay, BP Chiarizia, R Huber, VJ Herlinger, AW AF Dietz, ML Bond, AH Hay, BP Chiarizia, R Huber, VJ Herlinger, AW TI Ligand reorganization energies as a basis for the design of synergistic metal ion extraction systems SO CHEMICAL COMMUNICATIONS LA English DT Article ID CROWN-ETHERS; SOLVENT-EXTRACTION; WATER AB In the extraction of alkaline earth cations by acidic organophosphorus extractants, a correlation has been demonstrated between the effectiveness of the stereoisomers of dicyclohexano-18-crown-6 as synergists and the strain energy associated with conversion of the unbound crown ether to its complexed form. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dietz, ML (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 11 TC 24 Z9 24 U1 0 U2 5 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD JUL 7 PY 1999 IS 13 BP 1177 EP 1178 DI 10.1039/a902842k PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 214BR UT WOS:000081308200008 ER PT J AU Hummer, G AF Hummer, G TI Hydrophobic force field as a molecular alternative to surface-area models SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID FREE-ENERGIES; COMPUTER-SIMULATIONS; MEAN FORCE; CONFORMATIONAL EQUILIBRIA; TEMPERATURE-DEPENDENCE; NONPOLAR SOLUTES; AQUEOUS-SOLUTION; EXCLUDED VOLUME; HYDRATION SHELL; WATER-STRUCTURE AB An effective force field for hydrophobic interactions is developed based on a modified potential of-mean-force (PMF) expansion of the effective many-body interactions between nonpolar molecules in water. For the simplest nonpolar solutes in water, hard particles, the modified PMF expansion is exact in both limiting cases of infinite separation and perfect overlap. The hydrophobic interactions are parametrized by using the information-theory model of hydrophobic hydration. The interactions between nonpolar solutes are short-ranged and can be evaluated efficiently on a computer. The force field is compared with simulation data;for alkane conformational equilibria in water as well as a model for the formation of a hydrophobic core of a protein. The modified PMF expansion can be extended to solutes with attractive interactions, The observed accuracy, computational efficiency, and atomic detail of the model suggest that this simple hydrophobic force field can lead to a molecular alternative for phenomenological surface-area models with applications in ligand-binding and protein-folding studies. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hummer, G (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 91 TC 53 Z9 53 U1 2 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 7 PY 1999 VL 121 IS 26 BP 6299 EP 6305 DI 10.1021/ja984414s PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 217RB UT WOS:000081511800026 ER PT J AU Song, XD Swanson, BI AF Song, XD Swanson, BI TI Rational design of an optical sensing system for multivalent proteins SO LANGMUIR LA English DT Article ID BINDING; SPECIFICITY; RECOGNITION; RESONANCE; RECEPTOR; LECTINS; TOXINS AB A generic design principle for detection of multivalent interactions is described. A phospholipid bilayer consisting of natural and pyrene-derivatized phosphatidylcholines is used as both a supporting biomimetic surface and part of a signal transduction element. The pyrene excimer formed in the surface can act as fluorescence donor, and DABCY/BODIPY-FL covalently attached to receptor (GM1) can act as acceptors. Aggregation of the acceptor-tagged receptors resulting from multivalent binding of CT induces a decrease in efficiency of fluorescence quenching of the pyrene excimer by DABCY or energy transfer from pyrene excimer to BODIPY-FL. In the case using fluorescent acceptors that can undergo distance-dependent fluorescence self-quenching capability make acceptor fluorescence go down even further by th binding. This scheme can achieve signal amplification and high surface density of the optical transduction elements, which, in return, require relatively small surface area. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Swanson, BI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 15 TC 16 Z9 16 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 6 PY 1999 VL 15 IS 14 BP 4710 EP 4712 DI 10.1021/la980758k PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 216EG UT WOS:000081427800007 ER PT J AU Lu, P Jia, QX Findikoglu, AT AF Lu, P Jia, QX Findikoglu, AT TI Effects of homo-epitaxial LaAlO3 layer on microstructural properties of SrTiO3 films grown on LaAlO3 substrates SO THIN SOLID FILMS LA English DT Article DE epitaxy; strontium titanate; structural properties; transmission electron microscopy ID THIN-FILM; DIELECTRIC-PROPERTIES; YBA2CU3O7-X; DEPOSITION AB Effects of homo-epitaxial LaAlO3 (LAO) layer on microstructural properties of SrTiO3 (STO) films grown on LAO substrates have been investigated. The STO films were deposited by pulsed laser deposition (PLD) on LAO (100) substrate with and without a homo-epitaxial LAO (HE-LAO) layer. The microstructure of the STO films was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). TEM and HREM studies indicate the HE-LAG layer contains a much higher density of structural defects than the LAO substrate and the STO films grown on its top. In addition, the STO films deposited with the HE-LAO layer have a reduced planar defect (boundary) density relative to those films deposited directly on the LAO substrate. The reduced planar defect density in the STO film is strongly correlated with the previously observed improvement in microwave properties of devices based on these films. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Mexico Inst Min & Technol, Dept Mat Sci & Engn, Socorro, NM 87801 USA. Los Alamos Natl Lab, Superconduct Technol Ctr, Los Alamos, NM 87545 USA. RP New Mexico Inst Min & Technol, Dept Mat Sci & Engn, Socorro, NM 87801 USA. EM pinglu@nmt.edu RI Jia, Q. X./C-5194-2008 NR 15 TC 8 Z9 9 U1 2 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUL 6 PY 1999 VL 348 IS 1-2 BP 38 EP 43 DI 10.1016/S0040-6090(98)01767-2 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 208YH UT WOS:000081019700007 ER PT J AU Rintamaki, JI Gilgenbach, RM Cohen, WE Jaynes, RL Cuneo, ME Menge, PR AF Rintamaki, JI Gilgenbach, RM Cohen, WE Jaynes, RL Cuneo, ME Menge, PR TI Radio frequency plasma processing effects on the emission characteristics of a MeV electron beam cathode SO APPLIED PHYSICS LETTERS LA English DT Article ID FIELD-EMISSION AB Experiments have proven that surface contaminants on the cathode of an electron beam diode influence electron emission current and impedance collapse. This letter reports on an investigation to reduce parasitic cathode current loss and to increase high voltage hold off capabilities by reactive sputter cleaning of contaminants. Experiments have characterized effective radio frequency (rf) plasma processing protocols for high voltage anode-cathode (A-K) gaps using a two-stage argon/oxygen and argon rf plasma discharge. Time-resolved optical emission spectroscopy measures contaminant (hydrogen) and bulk cathode (aluminum) plasma emission versus transported axial electron beam current turn on. Experiments were performed at accelerator parameters: V = -0.7 to -1.1 MV, I(diode) = 3-30 kA, and pulse length = 0.4-1.0 mu s. Experiments using a two-stage low power (100 W) argon/oxygen rf discharge followed by a higher power (200 W) pure argon rf discharge yielded an increase in cathode turn-on voltage required for axial current emission from 662 +/- 174 kV to 981 +/- 97 kV. The turn-on time of axial current was increased from 100 +/- 22 to 175 +/- 42 ns. (C) 1999 American Institute of Physics. [S0003-6951(99)01827-6]. C1 Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. GE Lighting, Cleveland, OH 44112 USA. RP Rintamaki, JI (reprint author), Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. NR 12 TC 5 Z9 5 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 5 PY 1999 VL 75 IS 1 BP 31 EP 33 DI 10.1063/1.124267 PG 3 WC Physics, Applied SC Physics GA 211PL UT WOS:000081169300011 ER PT J AU Shen, TD Schwarz, RB AF Shen, TD Schwarz, RB TI Bulk ferromagnetic glasses prepared by flux melting and water quenching SO APPLIED PHYSICS LETTERS LA English DT Article ID MAGNETIC-PROPERTIES; AMORPHOUS-ALLOYS; STABILITY; SYSTEM; SOFT AB Several ferromagnetic bulk amorphous alloys of the type Fe-(Co, Cr, Mo, Ga, Sb)-P-B-C, containing between 62 and 71 at. % Fe, have been prepared in the form of 4-mm-diam rods. The glass synthesis consists of mechanically alloying the constituents, purifying the melts in B2O3 flux inside fused silica tubes, and quenching the melts at cooling rates on the order of 100 K/s. All these glasses have a large supercooled region T-x-T-g, ranging from 35 to 61 K, within which the glass can be shaped under a relatively small applied load. It is shown that the value of T-x-T-g depends strongly on the metalloid composition. These bulk metallic glasses have very low coercivity and low hysteresis losses. (C) 1999 American Institute of Physics. [S0003-6951(99)00927-4]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Shen, TD (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MS G755, Los Alamos, NM 87545 USA. NR 17 TC 275 Z9 305 U1 3 U2 36 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 5 PY 1999 VL 75 IS 1 BP 49 EP 51 DI 10.1063/1.124273 PG 3 WC Physics, Applied SC Physics GA 211PL UT WOS:000081169300017 ER PT J AU Ashby, CIH Bridges, MM Allerman, AA Hammons, BE Hou, HQ AF Ashby, CIH Bridges, MM Allerman, AA Hammons, BE Hou, HQ TI Origin of the time dependence of wet oxidation of AlGaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID WATER-VAPOR; ALAS; ALXGA1-XAS; LASERS; FILMS; GAAS AB The time dependence of the wet oxidation of high-Al-content AlGaAs can be either linear, indicating reaction-rate limitation, or parabolic, indicating diffusion-limited rates. The transition from linear to parabolic time dependence can be explained by the increased rate of the formation of intermediate As2O3 versus its reduction to elemental As. A steadily increasing thickness of the As2O3-containing region at the oxidation front will shift the process from the linear to the parabolic regime. This shift from reaction-rate limited (linear) to diffusion-limited (parabolic) time dependence is favored by increasing temperature or increasing Al mole fraction. (C) 1999 American Institute of Physics. [S0003-6951(99)01527-2]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Ashby, CIH (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 17 TC 33 Z9 35 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 5 PY 1999 VL 75 IS 1 BP 73 EP 75 DI 10.1063/1.124280 PG 3 WC Physics, Applied SC Physics GA 211PL UT WOS:000081169300025 ER PT J AU Cai, ZH Rodrigues, W Ilinski, P Legnini, D Lai, B Yun, W Isaacs, ED Lutterodt, KE Grenko, J Glew, R Sputz, S Vandenberg, J People, R Alam, MA Hybertsen, M Ketelsen, LJP AF Cai, ZH Rodrigues, W Ilinski, P Legnini, D Lai, B Yun, W Isaacs, ED Lutterodt, KE Grenko, J Glew, R Sputz, S Vandenberg, J People, R Alam, MA Hybertsen, M Ketelsen, LJP TI Synchrotron x-ray microdiffraction diagnostics of multilayer optoelectronic devices SO APPLIED PHYSICS LETTERS LA English DT Article ID EPITAXY; MOCVD AB Synchrotron-based x-ray microbeam techniques have been used to map crystallographic strain and multilayer thickness in micro-optoelectronic devices produced with the selective area growth technique. Our main results show that growth enhancements in InGaAsP multilayer device material are different for well and barrier material. Comparison with a vapor-phase model for selective area growth suggests that this difference is due to different vapor-phase incorporation rates for the group III metals. (C) 1999 American Institute of Physics. [S0003-6951(99)03927-3]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Cai, ZH (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Hybertsen, Mark S/0000-0003-3596-9754 NR 7 TC 33 Z9 33 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 5 PY 1999 VL 75 IS 1 BP 100 EP 102 DI 10.1063/1.124288 PG 3 WC Physics, Applied SC Physics GA 211PL UT WOS:000081169300034 ER PT J AU Ramamoorthy, M Pantelides, ST AF Ramamoorthy, M Pantelides, ST TI Atomic dynamics and defect evolution during oxygen precipitation and oxidation of silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID THERMAL DONORS; DIFFUSION; INTERFACE AB We report first-principles calculations in terms of which we propose a unified description of the atomic dynamics that underlie the nucleation and growth of SiO2 precipitates in Si and the oxidation of Si thin films. We identify a mechanism for the observed emission of Si interstitials and show that it eliminates electrically active defects without introducing dangling bonds. The results provide an explanation for the low defect density at the Si-SiO2 interface and suggest a novel family of electrically active interface defects that are akin to the "thermal donors" in Si. (C) 1999 American Institute of Physics. [S0003-6951(99)04724-5]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Ramamoorthy, M (reprint author), AT&T Bell Labs, Atlanta, GA USA. NR 17 TC 18 Z9 18 U1 2 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 5 PY 1999 VL 75 IS 1 BP 115 EP 117 DI 10.1063/1.124293 PG 3 WC Physics, Applied SC Physics GA 211PL UT WOS:000081169300039 ER PT J AU Peden, CHF Herman, GS Ismagilov, IZ Kay, BD Henderson, MA Kim, YJ Chambers, SA AF Peden, CHF Herman, GS Ismagilov, IZ Kay, BD Henderson, MA Kim, YJ Chambers, SA TI Model catalyst studies with single crystals and epitaxial thin oxide films SO CATALYSIS TODAY LA English DT Article; Proceedings Paper CT 2nd International Memorial G K Boreskov Conference on the Catalysis on the Eve of the XXI-Century Science and Engineering CY JUL 07-11, 1997 CL NOVOSIBIRSK, RUSSIA DE epitaxial thin oxide films; model catalyst studies; selective catalytic reduction ID ENERGY-ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; SURFACE-STRUCTURE; GROWTH; TIO2(100); WATER; MGO; OXIDATION; PRESSURE; KINETICS AB The paper describes recent results from our relatively new program to perform detailed studies of the catalytic properties of metal-oxide materials; in particular, to effect a determination of the active catalytic site(s) and the mechanism for reactions over this especially important class of heterogeneous catalysts. Issues of structure-sensitivity, poisoning and promotion, and competing reaction mechanisms are critical questions that need to be addressed in a detailed manner for catalysis by oxides. As just one important example, both surface (Langmui-Hinshelwood) and direct (Eley-Rideal) reaction mechanisms have been proposed for the selective catalytic reduction (SCR) reaction of nitrogen oxides (NOx) over vanadia/titania catalysts. For this program, we are using a number of unique, state-of-the-art capabilities available in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory; for example, the first molecular beam epitaxy (MBE) system dedicated to the growth of model metal-oxide films, and a unique moderate-pressure catalytic reactor/surface science apparatus. We describe the growth, characterization, and water adsorption properties of a thin Fe3O4(0 0 1) him grown on a lattice-matched MgO(0 0 1) substrate. Because our moderate pressure catalysis studies are preliminary at this point, we instead describe our previous results on the CO oxidation reaction over a Ru(0 0 0 1) model catalyst to demonstrate the utility of the experimental approach. We specifically discuss the possibility that this reaction occurs by an Eley-Rideal mechanism. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. OI Peden, Charles/0000-0001-6754-9928 NR 37 TC 33 Z9 33 U1 1 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5861 EI 1873-4308 J9 CATAL TODAY JI Catal. Today PD JUL 5 PY 1999 VL 51 IS 3-4 BP 513 EP 519 DI 10.1016/S0920-5861(99)00037-1 PG 7 WC Chemistry, Applied; Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 205NY UT WOS:000080828500015 ER PT J AU Balasubramanian, V Giddings, SB Lawrence, A AF Balasubramanian, V Giddings, SB Lawrence, A TI What do CFTs tell us about anti-de Sitter spacetimes? SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE 1 N expansion; D-branes; string duality; models of quantum gravity ID QUANTUM-FIELD-THEORY; STRING THEORY; SUPERGRAVITY; ABSORPTION; WORLD AB The AdS/CFT conjecture relates quantum gravity on anti-de Sitter (AdS) space to a conformal field theory (CFT) defined on the spacetime boundary. We interpret the CFT in terms of natural analogues of the bulk S-matrix. Our first approach finds the bulk S-matrix as a limit of scattering from an AdS bubble immersed in a space admitting asymptotic states. Next, we show how the periodicity of geodesics obstructs a standard LSZ prescription for scattering within global AdS. To avoid this subtlety we partition global AdS into patches within which CFT correlators reconstruct transition amplitudes of AdS states. Finally, we use the AdS/CFT duality to propose a large N collective field theory that describes local, perturbative supergravity. Failure of locality in quantum gravity should be related to the difference between the collective 1/N expansion and genuine finite N dynamics. C1 Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Seoul Natl Univ, Seoul 151, South Korea. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. SLAC, Theory Grp, Stanford, CA USA. LBNL, Theory Grp, Berkeley, CA USA. Duke Univ, Ctr Geometry & Theoret Phys, Durham, NC 27706 USA. RP Balasubramanian, V (reprint author), Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. EM vijayb@pauli.harvard.edu; lawrence@cartan.harvard.edu; lawrence@cartan.harvard.edu OI Lawrence, Albion/0000-0003-4116-045X NR 38 TC 66 Z9 66 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD JUL 5 PY 1999 IS 3 AR 001 PG 32 WC Physics, Particles & Fields SC Physics GA 215HD UT WOS:000081375000001 ER PT J AU Bertle, R Faber, M Greensite, J Olejnik, S AF Bertle, R Faber, M Greensite, J Olejnik, S TI The structure of projected center vortices in lattice gauge theory SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE solitons monopoles and instantons; confinement; lattice gauge field theories ID FINITE-TEMPERATURE; STRING TENSION; VACUUM; QCD; CONFINEMENT; FLUX AB We investigate the structure of center vortices in maximal center gauge of SU(2) lattice gauge theory at zero and finite temperature. In center projection the vortices (called P-vortices) form connected two dimensional surfaces on the dual four-dimensional lattice. At zero temperature we find, in agreement with the area law behaviour of Wilson loops, that most of the P-vortex plaquettes are parts of a single huge vortex. Small P-vortices, and short-range fluctuations of the large vortex surface, do not contribute to the string tension. All of the huge vortices detected in several thousand field configurations turn out to be unorientable. We determine the Euler characteristic of these surfaces and find that they have a very irregular structure with many handles. At finite temperature P-vortices exist also in the deconfined phase. They form cylindric objects which extend in time direction. After removal of unimportant short range fluctuations they consist only of space-space plaquettes, which is in accordance with the perimeter law behaviour of timelike Wilson loops, and the area law behaviour of spatial Wilson loops in this phase. C1 Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94117 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. Slovak Acad Sci, Inst Phys, SK-84228 Bratislava, Slovakia. RP Bertle, R (reprint author), Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. EM bertle@ap4.kph.tuwien.ac.at; faber@ap4.kph.tuwien.ac.at; greensit@stars.sfsu.edu; fyziolej@savba.sk RI Olejnik, Stefan/C-6145-2008 OI Olejnik, Stefan/0000-0002-0910-7125 NR 23 TC 35 Z9 35 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD JUL 5 PY 1999 IS 3 AR 019 PG 17 WC Physics, Particles & Fields SC Physics GA 215HD UT WOS:000081375000019 ER PT J AU Caprini, I Neubert, M AF Caprini, I Neubert, M TI Borel summation and momentum-plane analyticity in perturbative QCD SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE QCD; renormalization regularization and renormalons ID COUPLED-CHANNEL SCATTERING; HEAVY-QUARK; POWER CORRECTIONS; TAU-DECAYS; INVISIBLE RENORMALON; POLE MASS; ORDER; RENORMALIZATION; FRAGMENTATION; SINGULARITIES AB We derive a compact expression for the Borel sum of a QCD amplitude in terms of the inverse Mellin transform of the corresponding Borel function. The result allows us to investigate the momentum-plane analyticity properties of the Borel-summed Green functions in perturbative QCD. An interesting connection between the asymptotic behaviour of the Borel transform and the Landau singularities in the momentum plane is established. We consider for illustration the polarization function of massless quarks and the resummation of one-loop renormalon chains in the large-beta(0) limit, but our conclusions have a more general validity. C1 Natl Inst Phys & Nucl Engn, R-76900 Bucharest, Romania. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Caprini, I (reprint author), Natl Inst Phys & Nucl Engn, POB MG-6, R-76900 Bucharest, Romania. EM caprini@theor1.theory.nipne.ro; neubert@slac.stanford.edu NR 44 TC 18 Z9 18 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD JUL 5 PY 1999 IS 3 AR 007 PG 24 WC Physics, Particles & Fields SC Physics GA 215HD UT WOS:000081375000007 ER PT J AU Kraus, P Larsen, F Trivedi, SP AF Kraus, P Larsen, F Trivedi, SP TI The Coulomb branch of gauge theory from rotating branes SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE black holes in string theory; D-branes; black holes ID FIELD-THEORIES; BLACK-HOLES; SUPERGRAVITY; TEMPERATURE; ADS(5) AB At zero temperature the Coulomb Branch of N = 4 super Yang-Mills theory is described in supergravity by multi-center solutions with D3-brane charge. At finite temperature and chemical potential the vacuum degeneracy is lifted, and minima of the free energy are shown to have a supergravity description as rotating black D3-branes. In the extreme limit these solutions single out preferred points on the moduli space that can be interpreted as simple distributions of branes - for instance, a uniformly charged planar disc. We exploit this geometrical representation to study the thermodynamics of rotating black D3-branes. The low energy excitations of the system appear to be governed by an effective string theory which is related to the singularity in spacetime. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. RP Kraus, P (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. EM pkraus@theory.uchicago.edu; flarsen@theory.uchicago.edu; trivedi@fnth23.fnal.gov NR 31 TC 122 Z9 122 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD JUL 5 PY 1999 IS 3 AR 003 PG 27 WC Physics, Particles & Fields SC Physics GA 215HD UT WOS:000081375000003 ER PT J AU Muzny, CD Butler, BD Hanley, HJM Agamalian, M AF Muzny, CD Butler, BD Hanley, HJM Agamalian, M TI An ultra-small-angle neutron scattering study of the restructuring of sheared colloidal silica gels SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter AB Neutron scattering curves for a sheared colloidal silica gel were measured using a Bonse-Hart ultra-small-angle neutron scattering instrument. When they are combined with data taken from a conventional small-angle neutron scattering instrument, the accessible scattering vector range extends over approximately four orders of magnitude: 3 x 10(-4) < q (nm(-1)) < 3. A peak in the scattering datais observed at q = 2.7 x 10(-3) nm(-1) corresponding to a correlation length of 2.3 mu m. The scattering curves show an approximate power-law behaviour with an exponent of -2.9 over the range 4 x 10(-3) < q (nm(-1)) < 4 x 10(-2). These results are compared with our previously reported observation that an unsheared sample yields a correlation length of only similar to 20 nm with no observable power-law regime. The present data confirm that shear stresses induce a structural densification in gelling colloidal silica systems. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Oak Ridge Natl Lab, Spallat Neutron Source, Oak Ridge, TN 37831 USA. RP Muzny, CD (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. OI Agamalian, Michael/0000-0002-9112-2534 NR 8 TC 9 Z9 9 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 5 PY 1999 VL 11 IS 26 BP L295 EP L298 DI 10.1088/0953-8984/11/26/101 PG 4 WC Physics, Condensed Matter SC Physics GA 217NJ UT WOS:000081505600001 ER PT J AU Peters, RG Warner, BP Scott, BL Burns, CJ AF Peters, RG Warner, BP Scott, BL Burns, CJ TI C-H bond activation with actinides: The first example of intramolecular ring bite of a pentamethylcyclopentadienyl methyl group SO ORGANOMETALLICS LA English DT Article ID MOLECULAR-STRUCTURE; IMIDO COMPLEX; LIGAND; IMINES AB Thermolysis of (C5Me5)(2)U(=NAd)(2), 1 (Ad = 1-adamantyl), in benzene or hexane results in the intramolecular C-H bond activation of a methyl group on a pentamethylcyclopentadienyl ligand across the two imido functional groups. The product of this reaction has been spectroscopically and structurally characterized. The activation product is a reduced U(IV) metallocene bis(amide) complex with an N-bound methylene unit derived from the methyl group attached to one amide group. The activation parameters for this process have been determined; the results are consistent with a simple unimolecular process. This is the first example of intramolecular activation of a (C5Me5) methyl C-H bond in an actinide complex. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Burns, CJ (reprint author), Univ Calif Los Alamos Natl Lab, MS J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 23 TC 34 Z9 34 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUL 5 PY 1999 VL 18 IS 14 BP 2587 EP 2589 DI 10.1021/om990305q PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 217GC UT WOS:000081490800008 ER PT J AU Alaimo, PJ Bergman, RG AF Alaimo, PJ Bergman, RG TI Modeling the proposed intermediate in alkane carbon-hydrogen bond activation by Cp*(PMe3)Ir(Me)OTf: Synthesis and stability of novel organometallic iridium(V) complexes SO ORGANOMETALLICS LA English DT Article ID C-H BOND; RAY CRYSTAL-STRUCTURE; REDUCTIVE ELIMINATION; TRANSITION-METAL; OXIDATIVE ADDITION; 1,1-REDUCTIVE ELIMINATION; HYDRIDE COMPLEXES; CYCLIC ETHERS; MECHANISM; ALKYL AB Addition of HX to CH2Cl2 solutions of Cp*IrMe4 (Cp* = eta(5)-C5Me5) at low temperature provided Cp*Ir(Me)(3)X (X = Cl, 5; X = OSO2CF3 = OTf, 6). Both complexes are very thermally sensitive yet proved to be useful precursors for novel cationic iridium(V) complexes. Treatment of 6 with a variety of trisubstituted phosphines, arsines, and stibines (L) afforded compounds 7-12, [Cp*(L)IrMe3][OTf] (L = PMe3, 7; L = PEt3, 8; L = PPh3, 9; L = AsEt3, 10; L = AsPhs(3) 11; L = SbPh3, 12). Metathesis of the triflate anion of antimony complex 12 for the tetraphenylborate anion afforded [Cp*(SbPh3)IrMe3][BPh4] (13). The molecular structure of 13 was determined by single-crystal X-ray diffraction analysis. Complex 7 is a potential model for the proposed intermediate on themethane carbon-hydrogen bond activation reaction pathway by Cp*(PMe3)Ir(Me)OTf, and its relevance to this reaction is discussed. Complex 7 decomposed by reductive elimination of MeCp*. The remaining iridium fragment was trapped by added phosphine to form [cis-{PMe3}(4)IrMe2][OTf] (14) as an impure mixture. Reaction of 6 with excess dppm (dppm =Ph2PCH2PPh2) afforded [cis-{eta(2)-Ph2PCH2-PPh2}(2)IrMe2][OTf] (15). The molecular structure of 15 was determined by single-crystal X-ray structure analysis. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Bergman, RG (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 83 TC 50 Z9 50 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUL 5 PY 1999 VL 18 IS 14 BP 2707 EP 2717 DI 10.1021/om990255p PG 11 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 217GC UT WOS:000081490800025 ER PT J AU Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Glazov, A Golossanov, A Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McBride, PL McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW Wang, J White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED AF Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Glazov, A Golossanov, A Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McBride, PL McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW Wang, J White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED TI Observation of direct CP violation in K-S,K-L -> pi pi decays SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRAL KAON; SYSTEM AB We have compared the decay rates of K-L and K-S to pi(+)pi(-) and pi(0)pi(0) final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re(epsilon'/epsilon) is equal to [28.0 +/- 3.0(stat) +/- 2.8(syst)] x 10(-4). This result definitively establishes the existence of CP violation in a decay process. C1 Univ Wisconsin, Madison, WI 53706 USA. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Colorado, Boulder, CO 80309 USA. Elmhurst Coll, Elmhurst, IL 60126 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Osaka Univ, Toyonaka, Osaka 560, Japan. Rice Univ, Houston, TX 77005 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Virginia, Inst Nucl & Particle Phys, Charlottesville, VA 22901 USA. RP Alavi-Harati, A (reprint author), Univ Wisconsin, Madison, WI 53706 USA. RI Albuquerque, Ivone/H-4645-2012 OI Albuquerque, Ivone/0000-0001-7328-0136 NR 21 TC 366 Z9 368 U1 0 U2 4 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 JUL 5 PY 1999 VL 83 IS 1 BP 22 EP 27 DI 10.1103/PhysRevLett.83.22 PG 6 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000006 ER PT J AU Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B MayTal-Beck, S Meadows, B Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C AF Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B MayTal-Beck, S Meadows, B Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C TI Measurements of lifetimes and a limit on the lifetime difference in the neutral D-Meson system SO PHYSICAL REVIEW LETTERS LA English DT Article ID EFFECTIVE-FIELD-THEORY; CP VIOLATION; SEARCH; DECAYS; D-0 AB Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we report the first directly measured constraint on the decay-width difference Delta Gamma for the mass eigenstates of the D-0-(D) over bar(0) system. We obtain our result from lifetime measurements of the decays D-0 --> K(-)pi(+) and D-0 --> K-K+, under the assumption of CP invariance, which implies that the CP eigenstates and the mass eigenstates are the same. The lifetime of D-0 --> K-K+ (the CP-even final state) is tau(KK) = 0.410 +/- 0.011 +/- 0.006 ps, and the lifetime of D-0 --> K(-)pi(+) (an equal mixture of CP-odd and CP-even final states) is tau(K pi) = 0.413 +/- 0.003 +/- 0.004 ps. The decay-width difference is Delta Gamma = 2(Gamma(KK) - Gamma(K pi)) = 0.04 +/- 0.14 +/- 0.05 ps(-1). We relate these measurements to measurements of mixing in the neutral D-meson system. C1 Univ Mississippi, University, MS 38677 USA. Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. CINVESTAV, Mexico City 14000, DF, Mexico. Fermilab, Batavia, IL 60510 USA. IIT, Chicago, IL 60616 USA. Kansas State Univ, Manhattan, KS 66506 USA. Univ Massachusetts, Amherst, MA 01003 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Autonoma Puebla, Puebla 72570, Mexico. Univ S Carolina, Columbia, SC 29208 USA. Stanford Univ, Stanford, CA 94305 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. Tufts Univ, Medford, MA 02155 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RP Aitala, EM (reprint author), Univ Mississippi, University, MS 38677 USA. RI Anjos, Joao/C-8335-2013; Gobel Burlamaqui de Mello, Carla /H-4721-2016; Fernandez Tellez, Arturo/E-9700-2017; de Mello Neto, Joao/C-5822-2013 OI Gobel Burlamaqui de Mello, Carla /0000-0003-0523-495X; Fernandez Tellez, Arturo/0000-0003-0152-4220; de Mello Neto, Joao/0000-0002-3234-6634 NR 23 TC 70 Z9 71 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 JUL 5 PY 1999 VL 83 IS 1 BP 32 EP 36 DI 10.1103/PhysRevLett.83.32 PG 5 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000008 ER PT J AU Pisarski, RD Rischke, DH AF Pisarski, RD Rischke, DH TI A first order transition and parity violation in a color superconductor SO PHYSICAL REVIEW LETTERS LA English DT Article ID FINITE BARYON DENSITY; HOT GAUGE-THEORIES; PHASE-TRANSITION; QUARK MATTER; QCD; INSTANTONS; PLASMA; CHROMODYNAMICS; TEMPERATURE; AMPLITUDES AB In cold, dense quark matter, quarks of different flavor can form Cooper pairs which are antitriplets under color and have total spin J = 0. The transition to a phase where strange quarks condense with either up or down quarks is driven first order by the Coleman-Weinberg mechanism. At densities sufficiently high to (effectively) restore the axial U(1) symmetry, then relative to the ordinary vacuum, the condensation of up with down quarks (effectively) breaks parity spontaneously. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Brookhaven Natl Lab, RIKEN, BNL, Res Ctr, Upton, NY 11973 USA. RP Pisarski, RD (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 41 TC 107 Z9 107 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 JUL 5 PY 1999 VL 83 IS 1 BP 37 EP 40 DI 10.1103/PhysRevLett.83.37 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000009 ER PT J AU Bardayan, DW Blackmon, JC Brune, CR Champagne, AE Chen, AA Cox, JM Davinson, T Hansper, VY Hofstee, MA Johnson, BA Kozub, RL Ma, Z Parker, PD Pierce, DE Rabban, MT Shotter, AC Smith, MS Swartz, KB Visser, DW Woods, PJ AF Bardayan, DW Blackmon, JC Brune, CR Champagne, AE Chen, AA Cox, JM Davinson, T Hansper, VY Hofstee, MA Johnson, BA Kozub, RL Ma, Z Parker, PD Pierce, DE Rabban, MT Shotter, AC Smith, MS Swartz, KB Visser, DW Woods, PJ TI Observation of the astrophysically important 3(+) state in Ne-18 via elastic scattering of a radioactive P-17 beam from H-1 SO PHYSICAL REVIEW LETTERS LA English DT Article ID F-17(P,GAMMA)NE-18 AB The F-17(p, gamma)Ne-18 reaction is important in stellar explosions, but its rate has been uncertain because of an expected 3(+) state in Ne-18 that has never been conclusively observed. This state would provide a strong l = 0 resonance and, depending an its excitation energy, could dominate the stellar reaction rate. We have observed this missing 3(+) state by measuring the H-1(F-17, p)F-17 excitation function with a radioactive F-17 beam at the ORNL Holifield Radioactive Ion Beam Facility, We find that the state lies at a center-of-mass energy of E-r = 599.8 +/- 1.5(stat) +/- 2.0(sys) keV (E-x = 4523.7 +/- 2.9 keV) and has a width of Gamma = 18 +/- 2(stat) +/- 1(sys) keV. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Yale Univ, AW Wright Nucl Struct Lab, New Haven, CT 06511 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Tennessee Technol Univ, Dept Phys, Cookeville, TN 38505 USA. Univ Edinburgh, Dept Phys & Astron, Edinburgh EH9 3JZ, Midlothian, Scotland. Colorado Sch Mines, Dept Phys, Golden, CO 80401 USA. Chinese Inst Atom Energy, Beijing 102413, Peoples R China. Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RP Bardayan, DW (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RI Visser, Dale/A-8117-2009 OI Visser, Dale/0000-0002-2891-4731 NR 28 TC 116 Z9 116 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 JUL 5 PY 1999 VL 83 IS 1 BP 45 EP 48 DI 10.1103/PhysRevLett.83.45 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000011 ER PT J AU Krassig, B Dunford, RW Gemmell, DS Hasegawa, S Kanter, EP Schmidt-Bocking, H Schmitt, W Southworth, SH Weber, T Young, L AF Krassig, B Dunford, RW Gemmell, DS Hasegawa, S Kanter, EP Schmidt-Bocking, H Schmitt, W Southworth, SH Weber, T Young, L TI Compton double ionization of helium in the region of the cross-section maximum SO PHYSICAL REVIEW LETTERS LA English DT Article ID DOUBLE PHOTOIONIZATION; CHARGED-PARTICLES; SINGLE IONIZATION; SCATTERING; PHOTONS; HE; RATIO; ION AB The ratio of double-to-single ionization in helium by Compton scattering has been measured in the 8-28 keV x-ray energy range. The ratio attains a maximum value of 1.6% near 13 keV before descending towards the high-energy asymptotic region. The reported results resolve the discrepancies among previously published theoretical and experimental work in this energy range. The present data are most closely approximated by the results of the many-body perturbation theory calculation of Bergstrom et al. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Frankfurt, Inst Kernphys, D-60486 Frankfurt, Germany. Univ Freiburg, Fak Phys, D-79104 Freiburg, Germany. RP Krassig, B (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Weber, Thorsten/K-2586-2013 OI Weber, Thorsten/0000-0003-3756-2704 NR 25 TC 17 Z9 17 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 JUL 5 PY 1999 VL 83 IS 1 BP 53 EP 56 DI 10.1103/PhysRevLett.83.53 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000013 ER PT J AU Hentschel, HGE Family, F Braiman, Y AF Hentschel, HGE Family, F Braiman, Y TI Friction selection in nonlinear particle arrays SO PHYSICAL REVIEW LETTERS LA English DT Article ID STICK-SLIP MOTION; KONTOROVA-TOMLINSON MODEL; DRY FRICTION; LUBRICATED SURFACES; DYNAMICS; OSCILLATORS; ORIGIN AB When a discrete nonlinear array is driven across a periodic surface spatially coherent modes of motion can coexist associated with different average velocities due to resonant parametric forcing of the particle fluctuations by the center of mass motion. Depending on the coupling strength kappa and size of the array N, jumps in the minimum friction (maximum velocity) exhibited by the array occur at kappa(m)(N) similar to (N/m)(2) as new modes stabilize and are selected by the dynamics. The existence of such coherent modes allows both an effective low dimensional description of the dynamics to exist and the possibility for control of friction close to these instabilities. C1 Emory Univ, Dept Phys, Atlanta, GA 30322 USA. Oak Ridge Natl Lab, Ctr Engn Sci Adv Res, Comp Sci & Math Div, Oak Ridge, TN 37831 USA. RP Hentschel, HGE (reprint author), Emory Univ, Dept Phys, Atlanta, GA 30322 USA. NR 25 TC 28 Z9 28 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 JUL 5 PY 1999 VL 83 IS 1 BP 104 EP 107 DI 10.1103/PhysRevLett.83.104 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000026 ER PT J AU Koshelev, AE AF Koshelev, AE TI Crossing lattices, vortex chains, and angular dependence of melting line in layered superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID LOCK-IN TRANSITION; FLUX LATTICES; ANISOTROPIC SUPERCONDUCTORS; PHASE-TRANSITION; SINGLE-CRYSTALS; VORTICES; FIELD; MODEL; STATE AB We investigate vortex structure in very anisotropic layered superconductors at fields tilted with respect to the c axis. We show that even a small in-plane field does not tilt the vortex lattice but, instead, penetrates inside the superconductor in the form of Josephson vortices (JVs). At high c-axis magnetic field the phase field of the JV is built up from the phase perturbations created by displacements of pancake vortices. The crossing-lattices ground state leads to linear dependence of the c-axis melting field on the in-plane field, in agreement with recent experimental observations. At small fields stacks of JVs accumulate additional pancake stacks creating vortex rows with enhanced density. This mechanism explains the mixed chains-lattice state observed by decorations. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Koshelev, AE (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 27 TC 206 Z9 206 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 5 PY 1999 VL 83 IS 1 BP 187 EP 190 DI 10.1103/PhysRevLett.83.187 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000047 ER PT J AU Sandvik, AW Campbell, DK AF Sandvik, AW Campbell, DK TI Spin-Peierls transition in the Heisenberg chain with finite-frequency phonons SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM MONTE-CARLO; PHASE-DIAGRAM; 2 DIMENSIONS; SYSTEMS; MODEL; CUGEO3 AB We study the spin-Peierls transition in a Heisenberg spin chain coupled to optical bond phonons. Quantum Monte Carlo results for systems with up to N = 256 spins show unambiguously that the transition occurs only when the spin-phonon coupling a exceeds a critical value alpha(c). Using sum rules, we show that the phonon spectral function has divergent (for N --> infinity) weight extending to zero frequency for alpha < alpha(c). The phonon correlations decay with distance r as 1/r. This behavior is characteristic for all 0 < alpha < alpha(c) and the q = pi phonon does not soften (to zero frequency) at alpha = alpha(c). C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Sandvik, AW (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. OI Sandvik, Anders/0000-0002-5638-4619 NR 22 TC 42 Z9 42 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 JUL 5 PY 1999 VL 83 IS 1 BP 195 EP 198 DI 10.1103/PhysRevLett.83.195 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000049 ER PT J AU Niu, Q Wang, XD Kleinman, L Liu, WM Nicholson, DMC Stocks, GM AF Niu, Q Wang, XD Kleinman, L Liu, WM Nicholson, DMC Stocks, GM TI Adiabatic dynamics of local spin moments in itinerant magnets SO PHYSICAL REVIEW LETTERS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; IRON; SUSCEPTIBILITY; EQUATION; NICKEL AB Using the adiabatic approximation, we derive the equations of motion for local spin moments which are valid for itinerant as well as tight-binding spins. Material parameters in the equations of motion can be obtained using standard density functional methods, because they depend only on the energy and Berry phase of the constrained ground state of frozen spin configurations. For the calculation of spin waves in a collinear magnet, ii. is sufficient to know the quadratic forms of total energy and spin component along the symmetry axis as functions of the spin deviations from the ground state configuration. C1 Univ Texas, Dept Phys, Austin, TX 78712 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Niu, Q (reprint author), Univ Texas, Dept Phys, Austin, TX 78712 USA. RI Niu, Qian/G-9908-2013; Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 20 TC 89 Z9 91 U1 1 U2 10 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 JUL 5 PY 1999 VL 83 IS 1 BP 207 EP 210 DI 10.1103/PhysRevLett.83.207 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000052 ER PT J AU Julien, MH Jang, ZH Lascialfari, A Borsa, F Horvatic, M Caneschi, A Gatteschi, D AF Julien, MH Jang, ZH Lascialfari, A Borsa, F Horvatic, M Caneschi, A Gatteschi, D TI Proton NMR for measuring quantum level crossing in the magnetic molecular ring Fe-10 SO PHYSICAL REVIEW LETTERS LA English DT Article ID GROUND-STATE; MU-SR; DYNAMICS; SYSTEMS; (10); ANISOTROPY; RELAXATION; RESONANCE; ACETATE; PHASE AB The proton nuclear spin-lattice relaxation rate 1/T-1 has been measured as a function of temperature and magnetic field (up to 15 T) in the molecular magnetic ring Fe-10(OCH3)(20)(O2CCH2Cl)(10) (Fe10). Striking enhancement of 1/T-1 is observed around magnetic field values corresponding to a crossing between the ground state and the excited states of the molecule. We propose that this is due to a cross-relaxation effect between the nuclear Zeeman reservoir and the reservoir of the Zeeman levels of the molecule. This effect provides a powerful tool to investigate quantum dynamical phenomena at level crossing. C1 Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. Dipartimento Fis A Volta, I-27100 Pavia, Italy. Unita INFM Pavia, I-27100 Pavia, Italy. CNRS, High Field Magnet Lab, F-38042 Grenoble 9, France. MPI FKF, F-38042 Grenoble 9, France. Univ Florence, Dept Chem, I-50144 Florence, Italy. RP Julien, MH (reprint author), Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. RI Gatteschi, Dante/B-5429-2008; Julien, Marc-Henri/A-2352-2010 OI Gatteschi, Dante/0000-0002-4859-4317; Caneschi, Andrea/0000-0001-5535-3469; NR 26 TC 71 Z9 71 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 JUL 5 PY 1999 VL 83 IS 1 BP 227 EP 230 DI 10.1103/PhysRevLett.83.227 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000057 ER PT J AU Eguiluz, AG AF Eguiluz, AG TI Comment on "Self-consistent calculations of quasiparticle states in metals and semiconductors" - Eguiluz replies SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Eguiluz, AG (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 6 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 JUL 5 PY 1999 VL 83 IS 1 BP 242 EP 242 DI 10.1103/PhysRevLett.83.242 PG 1 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000063 ER PT J AU Schnier, JB Kaur, G Kaiser, A Stinson, SF Sausville, EA Gardner, J Nishi, K Bradbury, EM Senderowicz, AM AF Schnier, JB Kaur, G Kaiser, A Stinson, SF Sausville, EA Gardner, J Nishi, K Bradbury, EM Senderowicz, AM TI Identification of cytosolic aldehyde dehydrogenase 1 from non-small cell lung carcinomas as a flavopiridol-binding protein SO FEBS LETTERS LA English DT Article DE flavopiridol; CDK; aldehyde dehydrogenase class I; NSCLC; drug resistance ID DEPENDENT KINASE INHIBITOR; GROWTH-INHIBITION; P34(CDC2) KINASE; G(1) ARREST; APOPTOSIS; INDUCTION; L86-8275; PROGRESSION; MECHANISMS; EXPOSURE AB The synthetic flavone flavopiridol can be cytostatic or cytotoxic to mammalian cells, depending on the concentration of the drug and the duration of exposure. It has been shown to inhibit the cyclin-dependent kinase (CDK) family of cell cycle regulatory enzymes. However, the existence of additional potential targets for drug action remains a matter of interest to define, To identify cellular targets, flavopiridol was immobilized. CDKs, particularly CDK 4, bound weakly to immobilized flavopiridol when ATP was absent but not in its presence. Two proteins with molecular weights of 40 kDa and 120 kDa had high affinities to the immobilized flavopiridol independent of the presence of ATP, They were present in all cell lines analyzed: cervical (HeLa), prostate and non-small cell lung carcinoma (NSCLC) cell lines. A 60-kDa protein, which was present only in NSCLC cells and bound similarly well to immobilized flavopiridol, was identified as cytosolic aldehyde dehydrogenase class 1 (ALDH-1). The level of this protein correlated with the resistance of NSCLC cell lines to cytotoxicity caused by 500 nM flavopiridol but not higher flavopiridol concentrations, Despite binding to ALDN-1, there was no inhibition of dehydrogenase activity by flavopiridol concentrations as high as 20 mu M and flavopiridol was not metabolized by ALDH-1. The results suggest that high cellular levels of ALDH-1 may reduce cytotoxicity of flavopiridol and contribute to relative resistance to the drug. This is the first report that flavopiridol binds to proteins other than CDKs, (C) 1999 Federation of European Biochemical Societies. C1 Univ Calif Davis, Dept Biol Chem, Davis, CA 95616 USA. NCI, Lab Drug Discovery Res & Dev, Bethesda, MD 20892 USA. Univ Calif Davis, CEPRAP, Davis, CA 95616 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NCI, Div Canc Treament & Diag, Med Branch, DTP Clin Trials Unit, Bethesda, MD 20892 USA. RP Univ Calif Davis, Dept Biol Chem, Tupper Hall,1 Shields Ave, Davis, CA 95616 USA. EM jbschnier@ucdavis.edu NR 26 TC 51 Z9 53 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 EI 1873-3468 J9 FEBS LETT JI FEBS Lett. PD JUL 2 PY 1999 VL 454 IS 1-2 BP 100 EP 104 DI 10.1016/S0014-5793(99)00773-5 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 214ZX UT WOS:000081358400021 PM 10413104 ER PT J AU Guenet, L Toutain, B Guilleret, I Chauvel, B Deaven, LL Longmire, JL Le Gall, JY David, V Le Treut, A AF Guenet, L Toutain, B Guilleret, I Chauvel, B Deaven, LL Longmire, JL Le Gall, JY David, V Le Treut, A TI Human release factor eRF1: structural organisation of the unique functional gene on chromosome 5 and of the three processed pseudogenes SO FEBS LETTERS LA English DT Article DE human eRF1; genomic structure; gene family ID YEAST OMNIPOTENT SUPPRESSOR-45; PEPTIDE-CHAIN TERMINATION; DNA-SEQUENCES; HIGH HOMOLOGY; HUMAN CDNA; HLA-A; TRANSLATION; EXPRESSION; STOP; IDENTIFICATION AB In lower and higher eukaryotes, a family of tightly related proteins designated eRF1 (for eukaryotic release factor 1) catalyses termination of protein synthesis at all three stop codons, The human genome contains four eRF1 homologous sequences localised on chromosomes 5, 6, 7 and X. We report here the cloning and the structural analysis of the human eRF1 gene family. It appears that the gene located on chromosome 5 alone is potentially functional, whereas the other three sequences resemble processed pseudogenes. This is the first description of the structural organisation of the human eRF1 gene, which has been remarkably conserved during evolution and which is essential in the translation termination process. (C) 1999 Federation of European Biochemical Societies. C1 Fac Med, Dept Biochim & Biol Mol, F-35043 Rennes, France. Fac Med, CNRS, UPR41, F-35043 Rennes, France. Fac Med, Dept Biochim & Biol Mol, Lab Biochim Med A, F-35043 Rennes, France. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM 87545 USA. RP Guenet, L (reprint author), Fac Med, Dept Biochim & Biol Mol, 2 Ave Pr Leon Bernard,CS34317, F-35043 Rennes, France. RI Toutain, Bertrand/M-1982-2015 NR 27 TC 10 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD JUL 2 PY 1999 VL 454 IS 1-2 BP 131 EP 136 DI 10.1016/S0014-5793(99)00795-4 PG 6 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 214ZX UT WOS:000081358400027 PM 10413110 ER PT J AU Colmenarejo, G Tinoco, I AF Colmenarejo, G Tinoco, I TI Structure and thermodynamics of metal binding in the P5 helix of a group I intron ribozyme SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA structure and thermodynamics; NMR; metal binding; P5 helix; group I intron ID SELF-SPLICING INTRONS; STABLE RNA HAIRPIN; CRYSTAL-STRUCTURE; NUCLEIC-ACIDS; MAJOR GROOVE; COUPLING-CONSTANTS; NMR-SPECTROSCOPY; H-1 RESONANCES; RIBOSOMAL-RNA; WOBBLE PAIRS AB The solution structure of an RNA hairpin modelling the P5 helix of a group I intron, complexed with Co(NH3)(6)(3+), has been determined by nuclear magnetic resonance. Co(NH3)(6)(3+), which possesses a geometry very close to Mg(H2O)(6)(2+), was used to identify and characterize a Mg2+ binding site in the RNA. Strong and positive intermolecular nuclear Overhauser effect (NOE) cross-peaks define a specific complex in which the Co(NH3)(6)(3+) molecule is in the major groove of tandem G.U basepairs. The structure of the RNA is characterized by a very low twist angle between the two G.U base-pairs, providing a flat and narrowed major groove. The Co(NH3)(6)(3+), although highly localized, is free to rotate to hydrogen bond in several ways to the O4 atoms of the uracil bases and to N7 and O6 of the guanine bases. Negative and small NOE cross-peaks to other protons in the sequence reveal a non-specific or delocalized interaction, characterized by a high mobility of the cobalt ion. Mn2+ titrations of P5 show specific broadening of protons of the G.U basepairs that form the metal ion binding site, in agreement with the NOE data from Co(NH3)(6)(3+). Binding constants for the interaction of Co(NH3)(6)(3+) and of Mg2+ to P5 were determined by monitoring imino proton chemical shifts during titration of the RNA with the metal ions. Dissociation constants are on the order of 0.1 mM for Co(NH3)(6)(3+) and 1 mM for Mg2+. Binding studies were done on mutants with sequences corresponding to the three orientations of tandem G.U base-pairs. The affinities of Co(NH3)(6)(3+) and Mg2+ for the tandem G.U base-pairs depend strongly on their sequences; the differences can be understood in terms of the different structures of the corresponding metal ion-RNA complexes. Substitution of G.C or A.U for G.U pairs also affected the binding, as expected. These structural and thermodynamic results provide systematic new information about major groove metal ion binding in RNA. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Biol Struct, Phys Biosci Div, Berkeley, CA 94720 USA. RP Tinoco, I (reprint author), Glaxo Wellcome SA, Dept Quim Estruct, Parque Tecnol Madrid,Severo Ochoa 2, Madrid 28760, Spain. OI Colmenarejo, Gonzalo/0000-0002-8249-4547 FU NIGMS NIH HHS [GM 10840] NR 51 TC 59 Z9 59 U1 0 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUL 2 PY 1999 VL 290 IS 1 BP 119 EP 135 DI 10.1006/jmbi.1999.2867 PG 17 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 214DA UT WOS:000081311300009 PM 10388561 ER PT J AU Yang, H Kotz, KT Asplund, MC Wilkens, MJ Harris, CB AF Yang, H Kotz, KT Asplund, MC Wilkens, MJ Harris, CB TI Ultrafast infrared studies of bond activation in organometallic completes SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID C-H ACTIVATION; TRANSITION METAL CHEMISTRY; RESOLVED IR SPECTROSCOPY; OXIDATIVE ADDITION; TRISUBSTITUTED SILANES; HYDROCARBON SOLUTIONS; RHODIUM COMPLEX; MECHANISM; PHOTOCHEMISTRY; FEMTOSECOND C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Harris, CB (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Wilkens, Matthew/I-3720-2014 OI Wilkens, Matthew/0000-0001-6749-9318 NR 44 TC 26 Z9 26 U1 2 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD JUL PY 1999 VL 32 IS 7 BP 551 EP 560 DI 10.1021/ar970133y PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA 220RG UT WOS:000081680800002 ER PT J AU Harp, JM Hanson, BL Timm, DE Bunick, GJ AF Harp, JM Hanson, BL Timm, DE Bunick, GJ TI Macromolecular crystal annealing: evaluation of techniques and variables SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID X-RAY; CRYOCRYSTALLOGRAPHY; NUCLEOSOME; MOSAICITY; CORE AB Additional examples of successful application of macromolecular crystal annealing are presented. A qualitative evaluation of variables related to the annealing process was conducted using a variety of macromolecular crystals to determine in which cases parameters may be varied and in which cases the original macromolecular crystal annealing protocol is preferred. A hypothesis is presented relating the solvent content of the crystal to the specific protocol necessary for the successful application of annealing. C1 Univ Tennessee, Grad Sch Biomed Sci, Oak Ridge, TN 37831 USA. Indiana Univ, Sch Med, Dept Biochem & Mol Biol, Indianapolis, IN USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Harp, JM (reprint author), Univ Tennessee, Grad Sch Biomed Sci, Oak Ridge, TN 37831 USA. RI Hanson, Bryant Leif/F-8007-2010 OI Hanson, Bryant Leif/0000-0003-0345-3702 FU NIGMS NIH HHS [GM29818] NR 14 TC 50 Z9 50 U1 0 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD JUL PY 1999 VL 55 BP 1329 EP 1334 DI 10.1107/S0907444999005442 PN 7 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 218HL UT WOS:000081547100009 PM 10393299 ER PT J AU Quigg, C AF Quigg, C TI Electroweak symmetry breaking and the Higgs sector SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXVII International Meeting on Fundamental Physics CY FEB 01-05, 1999 CL SIERRA NEVADA, SPAIN SP CICYT, Junta de Andalucia, Univ Granada, Caja Gen Ahorros Granada ID FIRST MUON COLLIDER; STRONGLY INTERACTING WS; RENORMALIZATION-GROUP; STANDARD MODEL; CHIRAL HIERARCHIES; BOSON MASS; COSMOLOGICAL CONSTANT; WEAK INTERACTIONS; HADRON COLLIDERS; FIXED-POINTS AB These three lectures review the state of our understanding of electroweak interactions and the search for the agent of electroweak symmetry breaking. The themes of the lectures are (i) the electroweak theory and its experimental status, (ii) the standard-model Higgs boson, and (iii) aspects of electroweak theory beyond the standard SU(2)(L) X U(1)(Y) model. C1 Fermilab Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. RP Fermilab Natl Accelerator Lab, Dept Theoret Phys, POB 500, Batavia, IL 60510 USA. EM quigg@fnal.gov NR 135 TC 15 Z9 15 U1 0 U2 0 PU JAGIELLONIAN UNIV PRESS PI KRAKOW PA UL MICHALOWSKIEGO 9-2, KRAKOW, 31126, POLAND SN 0587-4254 EI 1509-5770 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD JUL PY 1999 VL 30 IS 7 BP 2145 EP 2192 PG 48 WC Physics, Multidisciplinary SC Physics GA 220YG UT WOS:000081697000002 ER PT J AU Deng, XT Zhu, BH AF Deng, XT Zhu, BH TI A randomized algorithm for the Voronoi diagram of line segments on coarse-grained multiprocessors SO ALGORITHMICA LA English DT Article DE coarse-grained parallel algorithms; Voronoi diagram; computational geometry ID PARALLEL; SET AB We present a randomized algorithm for computing the Voronoi diagram of line segments using coarse-grained parallel machines. Operating on P processors, for any input of n line segments, this algorithm performs O((n log n)/P) local operations per processor, O(n/P) messages per processor, and O(1) communication phases, with high probability for n = Omega (P3+epsilon). C1 York Univ, Dept Comp Sci, N York, ON M3J 1P3, Canada. City Univ Hong Kong, Dept Comp Sci, Kowloon, Hong Kong. Univ Calif Los Alamos Natl Lab, Grp CIC3, Los Alamos, NM 87545 USA. RP Deng, XT (reprint author), York Univ, Dept Comp Sci, N York, ON M3J 1P3, Canada. RI Deng, Xiaotie/E-8607-2011; Zhu, Binhai/A-2911-2008 OI Deng, Xiaotie/0000-0003-3189-5989; NR 37 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0178-4617 J9 ALGORITHMICA JI Algorithmica PD JUL-AUG PY 1999 VL 24 IS 3-4 BP 270 EP 286 DI 10.1007/PL00008263 PG 17 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 195HE UT WOS:000080243900006 ER PT J AU Taylor, RE Haynes, CV Kirner, DL Southon, JR AF Taylor, RE Haynes, CV Kirner, DL Southon, JR TI Radiocarbon analyses of modern organics at Monte Verde, Chile: No evidence for a local reservoir effect SO AMERICAN ANTIQUITY LA English DT Article ID ATMOSPHERIC C-14; CO2; ANTIQUITY; LAKE AB Radiocarbon measurements have been obtained on contemporary plant samples collected at the site of Monte Verde, Chile, to examine the possibility that a local C-14 reservoir effect impinges on the accuracy of the C-14 values obtained on previously recovered archaeological samples. The C-14 activity of the modem plants do not reveal any offset from expected contemporary C-14 values and thus provide no support for a major postulated reservoir effect at least for the recent past. Although there is, at present, no direct means of measuring potential C-14 reservoir offsets in the late Pleistocene for this region, we are not aware of any current data that would indicate that there have been major changes during geologically recent times. C1 Univ Calif Riverside, Dept Anthropol, Radiocarbon Lab, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. Univ Arizona, Dept Anthropol, Tucson, AZ 85721 USA. Univ Calif Lawrence Livermore Natl Lab, Lab Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Taylor, RE (reprint author), Univ Calif Riverside, Dept Anthropol, Radiocarbon Lab, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. NR 34 TC 8 Z9 8 U1 1 U2 9 PU SOC AMER ARCHAEOLOGY PI WASHINGTON PA 900 SECOND ST., NE STE 12, WASHINGTON, DC 20002-3557 USA SN 0002-7316 J9 AM ANTIQUITY JI Am. Antiq. PD JUL PY 1999 VL 64 IS 3 BP 455 EP 460 DI 10.2307/2694145 PG 6 WC Anthropology; Archaeology SC Anthropology; Archaeology GA 226TG UT WOS:000082037400005 ER PT J AU Alavanja, MCR Lubin, JH Mahaffey, JA Brownson, RC AF Alavanja, MCR Lubin, JH Mahaffey, JA Brownson, RC TI Residential radon exposure and risk of lung cancer in Missouri SO AMERICAN JOURNAL OF PUBLIC HEALTH LA English DT Article ID NONSMOKING WOMEN; DESIGN AB Objectives. This study investigated residential radon exposure and lung I cancer risk, using both standard radon dosimetry and a new radon monitoring technology that, evidence suggests, is a better measure of cumulative radon exposure. Methods. Missouri women (aged 30 to 84 years) newly diagnosed with primary lung cancer during the period January 1, 1993, to January 31, 1994, were invited to participate in this population-based case-control study. Both indoor air radon detectors and CR-39 alpha-particle detectors (surface moni- tors) were used. Results. When surface monitors were used, a significant trend in lung cancer odds ratios was observed for 20-year time-weighted-average radon concentrations. Conclusions. When surface monitors were used, but not when standard radon dosimetry was used, a significant lung cancer risk was found for radon concentrations at and above the action level for mitigation of houses currently used in the United States (148 Bqm(-3)). The risk was below the action level used in Canada (750 Bqm(-3)) and many European countries (200-400 Bqm(-3)). C1 NCI, Div Can Epidemiol & Genet, Bethesda, MD 20892 USA. Pacific NW Lab, Richland, WA 99352 USA. St Louis Univ, Sch Publ Hlth, Dept Community Hlth, St Louis, MO 63103 USA. RP Alavanja, MCR (reprint author), NCI, Div Can Epidemiol & Genet, Execut Plaza S,Room 8000,Mail Stop 8000, Bethesda, MD 20892 USA. FU NCI NIH HHS [N01-CP-21102] NR 26 TC 89 Z9 98 U1 0 U2 3 PU AMER PUBLIC HEALTH ASSOC INC PI WASHINGTON PA 1015 FIFTEENTH ST NW, WASHINGTON, DC 20005 USA SN 0090-0036 J9 AM J PUBLIC HEALTH JI Am. J. Public Health PD JUL PY 1999 VL 89 IS 7 BP 1042 EP 1048 DI 10.2105/AJPH.89.7.1042 PG 7 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 209QG UT WOS:000081059100011 PM 10394313 ER PT J AU Reeder, RJ Lamble, GM Northrup, PA AF Reeder, RJ Lamble, GM Northrup, PA TI XAFS study of the coordination and local relaxation around Co2+, Zn2+, Pb2+, and Ba2+ trace elements SO AMERICAN MINERALOGIST LA English DT Article ID MULTIPLE-SCATTERING CALCULATIONS; ABSORPTION FINE-STRUCTURE; SOLID-SOLUTIONS; PARTITION-COEFFICIENTS; CRYSTAL-STRUCTURE; CALCITE; GROWTH; SURFACE; SPECTROSCOPY; CARBONATES AB Analysis of divalent Co, Zn, Pb, and Ba XAFS spectra of synthetic and natural calcite samples containing trace concentrations of these heavy metals confirms their substitution in the unique Ca site in octahedral coordination with varying degrees of local distortion. The existence of each trace metal at the single site in the bulk crystal is significant in view of previous studies showing that these trace elements are incorporated differentially at multiple, structurally distinct surface sites occurring in nonequivalent growth steps on calcite surfaces. The octahedral coordination for Ba is particularly noteworthy because of its large size (35% larger than host Ca) and the fact that it rarely exists as a major constituent with such a low coordination number. Analysis of the local distortion and relaxation around the impurities shows a nearly complete contraction of the structure around Co2+ and Zn2+. The Co-O and Zn-O first-shell distances are only slightly longer than in CoCO3 and ZnCO3, with a site compliance of similar to 80-90%. Displacements of higher shells relative to those in calcite decrease rapidly, but irregularly, over a short distance, and the relaxation may be largely confined within 6-7 Angstrom of the impurity. The dilation around the large Pb2+ and Ba2+ ions in calcite also shows a high degree of site compliance (85-90%). Relaxation around Pb and Ba also appears to be restricted, but extending further for Ba than for Pb. The limited observations suggest that compliance of the octahedral site in calcite is larger than for the cation site in the rocksalt structure. The high compliance for the metal site in calcite may reflect the corner-sharing topology of the structure and is also probably the reason that calcite shows such a wide range of isovalent substitutions in nature. The findings also provide a direct indication of the local strain associated with a dilute substitutional solid solution. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Reeder, RJ (reprint author), SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. NR 42 TC 81 Z9 83 U1 0 U2 11 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD JUL-AUG PY 1999 VL 84 IS 7-8 BP 1049 EP 1060 PG 12 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 213FB UT WOS:000081261100007 ER PT J AU French, NB Priebe, SJ Haas, WJ AF French, NB Priebe, SJ Haas, WJ TI State-of-the-art mercury CEMs SO ANALYTICAL CHEMISTRY LA English DT Article C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. EM nina@skyplus.com NR 7 TC 15 Z9 15 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1999 VL 71 IS 13 BP 470A EP 475A PG 6 WC Chemistry, Analytical SC Chemistry GA 213HA UT WOS:000081265600012 PM 21649142 ER PT J AU Isola, NR Allman, SL Golovlov, VV Chen, CH AF Isola, NR Allman, SL Golovlov, VV Chen, CH TI Chemical cleavage sequencing of DNA using matrix-assisted laser desorption ionization time-of-flight mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID DESORPTION/IONIZATION; OLIGONUCLEOTIDES AB In this paper, we report for the first time use of laser desorption mass spectrometry for measurement of chemical cleavage sequencing products of DNA. Tn this method, the target DNA was labeled with biotin and subjected to chemical modification and cleavage according to the Maxam-Gilbert sequencing protocol. The biotin-containing fragments were captured by streptavidin-coated magnetic beads and separated from the other fragments. The captured fragments were released by hot ammonia treatment, and the released fragments were analyzed by mass spectrometry. Potential applications of this method in resolving sequence ambiguities and sequencing repeat sequences as well as in the analysis of DNA-protein interactions are discussed. C1 Oak Ridge Natl Lab, Div Life Sci, Photophys Grp, Oak Ridge, TN 37831 USA. RP Chen, CH (reprint author), Oak Ridge Natl Lab, Div Life Sci, Photophys Grp, Oak Ridge, TN 37831 USA. RI Allman, Steve/A-9121-2011 OI Allman, Steve/0000-0001-6538-7048 NR 24 TC 16 Z9 16 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1999 VL 71 IS 13 BP 2266 EP 2269 DI 10.1021/ac990151o PG 4 WC Chemistry, Analytical SC Chemistry GA 213HA UT WOS:000081265600016 PM 10405596 ER PT J AU Groenewold, GS Appelhans, AD Gresham, GL Olson, JE Jeffery, M Wright, JB AF Groenewold, GS Appelhans, AD Gresham, GL Olson, JE Jeffery, M Wright, JB TI Analysis of VX on soil particles using ion trap secondary ion mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID CHEMICAL WARFARE AGENTS; CAPILLARY GAS-CHROMATOGRAPHY; STATIC SIMS; TRIBUTYL-PHOSPHATE; LEAF SURFACES; IONIZATION; METHYLPHOSPHONOTHIOATE; DEGRADATION; PRODUCTS; SULFIDE AB The direct detection of the nerve agent VX (methylphosphonothioic acid, S-[2-[bis(1-methylethyl)amino]ethyl] O-ethyl ester) on milligram quantities of soil particles has been achieved using ion trap secondary ion mass spectrometry (IT-SIMS). VX is highly adsorptive toward a wide variety of surfaces; this attribute makes detection using gas-phase approaches difficult but renders the compound very amenable to surface detection. An ion trap mass spectrometer, modified to perform SIMS, was employed in the present study. A primary ion beam (ReO4-) was fired on axis through the ion trap, where it impacted the soil particle samples. [VX + H](+), [VX + H](+) fragment ions, and ions from the chemical background were sputtered into the gas-phase environment of the ion trap, where they were either scanned out or isolated and fragmented (MS2). At a surface concentration of 0.4 monolayer, intact [VX + H](+), and its fragment ions, were readily observable above background. However, at lower concentrations, the secondary ion signal from VX became obscured by ions derived from the chemical background on the surface of the soil particles. MS2 analysis using the ion trap was employed to improve detection of lower concentrations of VX: detection of the S-34 isotopic ion of [VX + H](+), present at a surface concentration of similar to 0.002 monolayer, was accomplished. The study afforded the opportunity to investigate the fragmentation chemistry of VX Semiempirical calculations suggest strongly that the molecule is protonated at the N atom. Deuterium labeling showed that formation of the base peak ion (C2H4)N(i-C3H7)(2)(+) involves transfer of the amino proton to the phosphonothioate moiety prior to, or concurrent with, C-S bond cleavage. To manage the risk associated with working with the compound, the vacuum unit of the IT-SIMS was located in a hood, connected by cables to the externally located electronics and computer. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. USA, W Desert Test Ctr, Dugway, UT 84022 USA. USA Edgewood Res, Ctr Dev & Engn, Aberdeen Proving Ground, MD 21010 USA. RP Groenewold, GS (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 33 TC 32 Z9 33 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1999 VL 71 IS 13 BP 2318 EP 2323 DI 10.1021/ac981391r PG 6 WC Chemistry, Analytical SC Chemistry GA 213HA UT WOS:000081265600023 PM 10405600 ER PT J AU Brooks, SA Ambrose, WP Kuhr, WG AF Brooks, SA Ambrose, WP Kuhr, WG TI Micrometer dimension derivatization of biosensor surfaces using confocal dynamic patterning SO ANALYTICAL CHEMISTRY LA English DT Article ID FLUORESCENCE; PHOTOBIOTIN; ACTIVATION; ELECTRODES; MOLECULES; BIOTIN; DNA AB Using laser scanning confocal optics in conjunction with avidin/biotin technology, micrometer-sized patterns of biomolecules were fabricated on glassy-carbon and fused-silica surfaces. Photoactive biotin was immobilized using the 325-nm line of a Helium-Cadmium laser, which was focused through a 25x or 100x quartz microscope objective. A three-dimensional piezoelectric micromanipulator was used to position the sample surface in the focal plane of the microscope objective and to create patterns on the focused surface. Biotin patterns with line widths of 5-20 mu m were produced by varying the scan speed of the micromanipulator while exposing the surface to the laser. The integrity of the immobilized biotin was confirmed by subsequent derivatization with fluorescently labeled avidin. Fluorescence microscopy with a cooled charge coupled device (CCD) imaging system was used to visualize the distribution of biotin and fluorescent avidin within the patterns created by the laser. C1 Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Kuhr, WG (reprint author), Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. OI Kuhr, Werner/0000-0003-3210-4341 FU NIDDK NIH HHS [5F32DK09770-02] NR 20 TC 17 Z9 17 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1999 VL 71 IS 13 BP 2558 EP 2563 DI 10.1021/ac9814546 PG 6 WC Chemistry, Analytical SC Chemistry GA 213HA UT WOS:000081265600057 PM 10405614 ER PT J AU Grossman, MJ Lee, MK Prince, RC Garrett, KK George, GN Pickering, IJ AF Grossman, MJ Lee, MK Prince, RC Garrett, KK George, GN Pickering, IJ TI Microbial desulfurization of a crude oil middle-distillate fraction: Analysis of the extent of sulfur removal and the effect of removal on remaining sulfur (vol 65, pg 181, 1999) SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Correction C1 Exxon Res & Engn Co, Annandale, NJ 08801 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Grossman, MJ (reprint author), Exxon Res & Engn Co, Route 22 E, Annandale, NJ 08801 USA. RI Grossman, Matthew/K-3357-2012; George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013 NR 1 TC 2 Z9 2 U1 0 U2 0 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD JUL PY 1999 VL 65 IS 7 BP 3264 EP 3264 PG 1 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 212CP UT WOS:000081199000069 ER PT J AU Brady, PV Papenguth, HW Kelly, JW AF Brady, PV Papenguth, HW Kelly, JW TI Metal sorption to dolomite surfaces SO APPLIED GEOCHEMISTRY LA English DT Article ID ARAGONITE SURFACES; CALCITE SURFACE; SOLID-SOLUTION; SEAWATER; PRECIPITATION; ADSORPTION; MODEL; 25-DEGREES-C; CHEMISTRY AB Potential human intrusion into the Waste Isolation Pilot Plant (WIPP) might release actinides into the Culebra Dolomite where sorption reactions will affect of radiotoxicity from the repository. Using a limited residence time reactor the authors have measured Ca, Mg, Nd adsorption/exchange as a function of ionic strength, P(CO2), and pH at 25 degrees C. By the same approach, but using as input radioactive tracers, adsorption/exchange of Am, Pu, U, and Np on dolomite were measured as a function of ionic strength, P(CO2) and pH at 25 degrees C. Metal adsorption is typically favored at high pH. Calcium and ME adsorb in near-stoichiometric proportions except at high pH. Adsorption of Ca and Mg is diminished at high ionic strengths (e.g., 0.5M NaCl) pointing to association of Na(+) with the dolomite surface, and the possibility that Ca and Mg sorb as hydrated, outer-sphere complexes. Sulfate amplifies sorption of Ca and Mg, and possibly Nd as well. Exchange of Nd for surface Ca is favored at high pH, and when Ca levels are low. Exchange for Ca appears to control attachment of actinides to dolomite as well, and high levels of Ca(2+) in solution will decrease K(d)s. At the same time, to the extent that high P(CO2)s increase Ca(2+) levels, K(d)s Will decrease with CO(2) levels as well, but only if sorbing actinide-carbonate complexes are not observed to form (Am-carbonate complexes appear to sorb; Pu-complexes might sorb as well. U-carbonate complexation leads to desorption). This indirect CO(2) effect is observed primarily at, and above, neutral pH. High NaCl levels do not appear to affect to actinide K(d)s. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Geochem REs MS0750, Albuquerque, NM 87185 USA. RP Brady, PV (reprint author), Sandia Natl Labs, Geochem REs MS0750, POB 5800, Albuquerque, NM 87185 USA. EM pvbrady@sandia.gov NR 33 TC 32 Z9 33 U1 1 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0883-2927 J9 APPL GEOCHEM JI Appl. Geochem. PD JUL PY 1999 VL 14 IS 5 BP 569 EP 579 DI 10.1016/S0883-2927(98)00085-7 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 191VY UT WOS:000080043300003 ER PT J AU Buck, EC Bates, JK AF Buck, EC Bates, JK TI Microanalysis of colloids and suspended particles from nuclear waste glass alteration SO APPLIED GEOCHEMISTRY LA English DT Article ID URANYL SILICATE MINERALS; ENERGY-LOSS SPECTROSCOPY; CHEMISTRY; ACTINIDES; COMPLEXES; ELECTRON; DISSOLUTION; TRANSPORT; MOBILITY; URANIUM AB Fully radioactive and non-radioactive Savannah River Laboratory (SRL) borosilicate glasses were reacted with water under static conditions at glass surface area to leachant volume (S/V) ratios of 340 m(-1), 2000 m(-1), and 20 000 m(-1) for times varying from several days to several years at 90 degrees C. A radioactive SRL 200 glass was also reacted under intermittent flow conditions at 90 degrees C. Colloidal and suspended glass alteration particles present in the leachates of these tests were examined with analytical transmission electron microscopy (AEM). The major colloidal phase identified in all tests was partially crystalline dioctahedral smectite clay. At 20 000 m(-1), the clay colloids flocculate and sediment, becoming attached to available surfaces when the ionic strength reached a value of about 0.3-0.5 mol . kg(-1). Clay colloids remained stable in the solution for the duration of the experiment in tests conducted at S/V values of 2000 m(-1) and 340 m(-1). Calcite, dolomite, and transition metal oxide particles were more common in the intermittent flow tests but were also found in the static tests. Layered, Mn-bearing minerals, birnessite and asbolane, were found exclusively in the intermittent flow tests. Weeksite and a U-Ti phase were found exclusively in the static tests. Partially crystalline rare earth-bearing calcium phosphate colloids, structurally related to rhabdophane, were found in both types of tests. These particles exhibited a negative Ce anomaly. The affinity of phosphate for Pu was investigated through geochemical modeling. The results from this study and others were used to form a picture of colloidal development in the leachate from waste glass testing. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Buck, EC (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Buck, Edgar/D-4288-2009; Buck, Edgar/N-7820-2013 OI Buck, Edgar/0000-0001-5101-9084 NR 45 TC 31 Z9 32 U1 2 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0883-2927 J9 APPL GEOCHEM JI Appl. Geochem. PD JUL PY 1999 VL 14 IS 5 BP 635 EP 653 DI 10.1016/S0883-2927(98)00088-2 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 191VY UT WOS:000080043300007 ER PT J AU Yamazaki, T Gullikson, E Miyata, N Koike, M Harada, Y Mrowka, S Kleineberg, U Underwood, JH Yanagihara, MM Sano, K AF Yamazaki, T Gullikson, E Miyata, N Koike, M Harada, Y Mrowka, S Kleineberg, U Underwood, JH Yanagihara, MM Sano, K TI Comparison of mechanically ruled versus holographically varied line-spacing gratings for a soft-x-ray flat-field spectrograph SO APPLIED OPTICS LA English DT Article ID MONOCHROMATORS; SPECTROMETER; PLASMA AB Recent progress in the design of aspheric wave front recording systems has permitted the manufacture of holographic gratings with highly variable groove densities that are suitable for flat-field spectrographs. A holographic grating thus recorded was processed to produce a laminar profile by use of reactive-ion etching. Measurements are reported of the absolute diffraction efficiency of this grating and of a comparable mechanically ruled grating. It is found that the holographic grating is much more effective in suppressing the higher orders. The spectral resolution was determined by use of a carbon K alpha x-ray generator and a spectrograph with an imaging detector. The spectral resolution of the holographic grating was approximately 3 times worse than that of the ruled grating. (C) 1999 Optical Society of America. C1 Japan Atom Energy Res Inst, Kansai Res Estab, Adv Photon Res Ctr, Neyagawa, Osaka 5720019, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Tohoku Univ, Sci Measurements Res Inst, Aoba Ku, Sendai, Miyagi 9808577, Japan. Shimadzu Co Ltd, Prod Engn Lab, Nakagyo Ku, Kyoto 6048511, Japan. RP Yamazaki, T (reprint author), Japan Atom Energy Res Inst, Kansai Res Estab, Adv Photon Res Ctr, 25-1 Miiminami Machi, Neyagawa, Osaka 5720019, Japan. EM yamazaki@apr.jaeri.go.jp NR 12 TC 14 Z9 14 U1 1 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1999 VL 38 IS 19 BP 4001 EP 4003 DI 10.1364/AO.38.004001 PG 3 WC Optics SC Optics GA 212GF UT WOS:000081208400003 PM 18323875 ER PT J AU Hyde, RA AF Hyde, RA TI Eyeglass. 1. Very targe aperture diffractive telescopes SO APPLIED OPTICS LA English DT Article ID HOLOGRAM OPTICAL ELEMENTS AB The Eyeglass is a very large aperture (25-100-m) space telescope consisting of two distinct spacecraft, separated ia space by several kilometers. a diffractive lens provides the telescope's large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope's eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band (Delta lambda/lambda similar to 0.1), multiband, or continuous spectral coverage. (C) 1999 Optical Society of America. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Hyde, RA (reprint author), Lawrence Livermore Natl Lab, Mail Stop L-477,7000 East Ave, Livermore, CA 94550 USA. NR 18 TC 53 Z9 54 U1 3 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1999 VL 38 IS 19 BP 4198 EP 4212 DI 10.1364/AO.38.004198 PG 15 WC Optics SC Optics GA 212GF UT WOS:000081208400030 PM 18323902 ER PT J AU Sankaran, V Schonenberger, K Walsh, JT Maitland, DJ AF Sankaran, V Schonenberger, K Walsh, JT Maitland, DJ TI Polarization discrimination of coherently propagating light in turbid media SO APPLIED OPTICS LA English DT Article ID SCATTERING MEDIUM; WAVES; CELLS; RANGE AB We describe the use of degree of polarization to discriminate unscattered and weakly scattered light from multiply scattered light in an optically turbid material. We use spatially resolved measurements of the degree of polarization to compare how well linearly and circularly polarized light survives in a sample. Experiments were performed on common tissue phantoms consisting of polystyrene and Intralipid microsphere suspensions and on adipose and arterial tissue. The results indicate that polarization is maintained even after unpolarized irradiance through each sample has been extinguished by several orders of magnitude. The results also show that polarized light propagation in common tissue phantoms is distinctly different hom polarized light propagation in the two tissues investigated. Further, these experiments illustrate when polarization is an effective discrimination criterion and when it is not. Tbe potential of a polarization-based discrimination scheme to image through the biological and nonbiological samples investigated here is also discussed. (C) 1999 Optical Society of America. C1 Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94550 USA. Northwestern Univ, Dept Biomed Engn, Evanston, IL 60208 USA. RP Sankaran, V (reprint author), Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94550 USA. EM sankaran1@llnl.gov RI Walsh, Joseph/B-7636-2009 NR 28 TC 71 Z9 72 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1999 VL 38 IS 19 BP 4252 EP 4261 DI 10.1364/AO.38.004252 PG 10 WC Optics SC Optics GA 212GF UT WOS:000081208400036 PM 18323908 ER PT J AU Istratov, AA Hieslmair, H Weber, ER AF Istratov, AA Hieslmair, H Weber, ER TI Iron and its complexes in silicon SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Review ID ELECTRON-PARAMAGNETIC-RESONANCE; N-TYPE SILICON; LEVEL TRANSIENT SPECTROSCOPY; TRANSITION-METAL IMPURITIES; ENHANCED DEFECT REACTIONS; P-TYPE SILICON; BORON-DOPED SILICON; AU-FE COMPLEX; ISOELECTRONIC BOUND EXCITONS; INTERSTITIAL 3D IMPURITIES AB This article is the first in a series of two reviews on the properties of iron in silicon. It offers a comprehensive summary of the current state of understanding of fundamental physical properties of iron and its complexes in silicon. The first section of this review discusses the position of iron in the silicon lattice and the electrical properties of interstitial iron. Updated expressions for the solubility and the diffusivity of iron in silicon are presented, and possible explanations for conflicting experimental data obtained by different groups are discussed. The second section of the article considers the electrical and the structural properties of complexes of interstitial iron with shallow accepters (boron, aluminum, indium, gallium, and thallium), shallow donors (phosphorus and arsenic) and other impurities (gold, silver, platinum, palladium, zinc, sulfur, oxygen, carbon, and hydrogen). Special attention is paid to the kinetics of iron pairing with shallow accepters, the dissociation of these pairs, and the metastability of iron-acceptor pairs. The parameters of iron-related defects in silicon are summarized in tables that include more than 30 complexes of iron as detected by electron paramagnetic resonance (EPR) and almost 20 energy levels in the band gap associated with iron. The data presented in this review illustrate the enormous complexing activity of iron, which is attributed to the partial or complete (depending on the temperature and the conductivity type) ionization of iron as well as the high diffusivity of iron in silicon. It is shown that studies of iron in silicon require exceptional cleanliness of experimental facilities and highly reproducible diffusion and temperature ramping (quenching) procedures. Properties of iron that are not yet completely understood and need further research are outlined. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Mat Sci & Engn, MS 62-203,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM istratov@socrates.berkeley.edu; hhiesl@argon.eecs.berkeley.edu; weber@socrates.berkeley.edu OI Hieslmair, Henry/0000-0002-5842-1882 NR 368 TC 362 Z9 373 U1 9 U2 89 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0947-8396 EI 1432-0630 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD JUL PY 1999 VL 69 IS 1 BP 13 EP 44 DI 10.1007/s003390050968 PG 32 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 210NQ UT WOS:000081111900002 ER PT J AU Su, H Yeung, ES AF Su, H Yeung, ES TI Study of cell degranulation with simultaneous microscope imaging and capillary electrophoresis SO APPLIED SPECTROSCOPY LA English DT Article DE microscopy; imaging; capillary electrophoresis; serotonin; exocytosis ID INDUCED NATIVE FLUORESCENCE; MAST-CELLS; CHROMAFFIN CELLS; EXOCYTOSIS; RELEASE AB The physical release of single granules from individual rat peritoneal mast cells (RPMCs) was monitored by video recording of the degranulating cells by a high-resolution charge-coupled device (CCD) microscope system. The bright granular core disappears from the image as the vesicular content is dissolved on contact with the extra-cellular fluid. After a fixed time delay, the exocytotic product, serotonin, was detected by capillary electrophoresis coupled with laser-induced native fluorescence (LINF-CE). The timing of the two events is mostly correlated, which supports a fast release mechanism of the granular products. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. NR 16 TC 0 Z9 0 U1 0 U2 2 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUL PY 1999 VL 53 IS 7 BP 760 EP 763 DI 10.1366/0003702991947522 PG 4 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 222WL UT WOS:000081808300007 ER PT J AU Niemczyk, TM Zhang, SB Franke, JE Haaland, DM AF Niemczyk, TM Zhang, SB Franke, JE Haaland, DM TI Quantitative determination of borophosphosilicate glass thin-film properties using infrared emission spectroscopy SO APPLIED SPECTROSCOPY LA English DT Article DE borophosphosilicate glass films; partial least-squares; infrared emission spectra ID PHOSPHOSILICATE GLASS; SILICON-WAFERS; REFLECTION; CALIBRATION; PARAMETERS; SPECTRA AB We have completed an experimental study to investigate the use of infrared emission spectroscopy (IRES) for the quantitative analysis of borophosphosilicate glass (BPSG) thin films on silicon monitor wafers. Experimental parameters investigated included temperatures within the range used in the microelectronics industry to produce these films so that the potential for using the IRES technique for real-time monitoring of the film deposition process could be evaluated. The film properties that were investigated included boron content, phosphorus content, film thickness, and film temperature. The studies were conducted over two temperature ranges, 125 to 225 degrees C and 300 to 400 degrees C. The latter temperature range includes realistic processing temperatures for the chemical vapor deposition (CVD) of the BPSG films, Partial least-squares (PLS) multivariate calibration methods were applied to spectral and film property calibration data. The cross-validated standard errors of prediction (CVSEP) from the PLS analysis of the IRES spectra of 21 calibration samples each measured at six temperatures in the 300 to 400 degrees C range were found to be 0.09 wt % for B, 0.08 wt % for P, 3.6 nm for film thickness, and 1.9 degrees C for temperature. Upon lowering the spectral resolution from 4 to 32 cm(-1) and decreasing the number of spectral scans from 128 to 1, we were able to determine that all the film properties could be measured in less than one second to the precision required for the manufacture and quality control of integrated circuits. Thus, real-time in situ monitoring of BPSG thin films formed by CVD deposition on Si monitor wafers is possible with the methods reported here. C1 Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Niemczyk, TM (reprint author), Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. NR 16 TC 5 Z9 5 U1 1 U2 2 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUL PY 1999 VL 53 IS 7 BP 822 EP 828 DI 10.1366/0003702991947397 PG 7 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 222WL UT WOS:000081808300018 ER PT J AU Littlejohn, D Lucas, D Han, L AF Littlejohn, D Lucas, D Han, L TI Bent silica fiber evanescent absorption sensors for near-infrared spectroscopy SO APPLIED SPECTROSCOPY LA English DT Article DE near-infrared; optical fibers; sensors; evanescent field ID OPTICAL-FIBER; WAVE SPECTROSCOPY; ABSORBENCY AB Silica optical fibers have been modified to improve their sensitivity as evanescent wave sensors for liquids. A section of fiber is stripped of its cladding and bent or coiled, which significantly increases the evanescent wave interaction with the surrounding environment. The effect of sensor shape, solute concentration, refractive index, and temperature on the sensor response is discussed. C1 Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Lucas, D (reprint author), Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 17 TC 18 Z9 18 U1 1 U2 4 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUL PY 1999 VL 53 IS 7 BP 845 EP 849 DI 10.1366/0003702991947423 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 222WL UT WOS:000081808300021 ER PT J AU Kwan, LT Reed, BR Eberling, JL Schuff, N Tanabe, J Norman, D Weiner, MW Jagust, WJ AF Kwan, LT Reed, BR Eberling, JL Schuff, N Tanabe, J Norman, D Weiner, MW Jagust, WJ TI Effects of subcortical cerebral infarction on cortical glucose metabolism and cognitive function SO ARCHIVES OF NEUROLOGY LA English DT Article ID POSITRON EMISSION TOMOGRAPHY; ALZHEIMERS-DISEASE; VASCULAR DEMENTIA; COMPUTED-TOMOGRAPHY; RISK-FACTORS; BLOOD-FLOW; THALAMIC STROKE; WORKING-MEMORY; BRAIN VOLUME; WHITE-MATTER AB Background: The mechanism of dementia in subcortical cerebral infarction is incompletely understood. Objective: To determine how cognitive function is related to cortical metabolism in patients with subcortical infarction and a continuum of cognitive impairment. Methods: We used positron emission tomography (PET) and the glucose metabolic tracer fludeoxyglucose F 18 to study 8 patients with subcortical stroke and normal cognitive function (S-CN), 5 patients with subcortical stroke and cognitive impairment (S-CI) who did not have dementia, 8 patients with subcortical stroke and dementia (S-D), and 11 controls with no cognitive impairment or stroke. A subset of patients had absolute regional cerebral metabolic rate of glucose (CMRglc) determined, while in all subjects regional tracer uptake normalized to whole brain tracer uptake was calculated. PET data were analyzed by constructing volumes of interest using coregistered magnetic resonance imaging data and correcting the PET data for atrophy. Results: Global CMRglc was significantly lower in the patients with S-D than in the control and S-CN groups, with S-CI rates intermediate to those of the S-D and S-CN groups. Absolute regional CMRs of glucose were similar in the S-D and S-CI groups and in the control and S-CN groups. The regional pattern, however, showed lower right frontal regional CMRglc ratios in all stroke groups compared with the controls. There were modest correlations between performance on the Mini-Mental State Examination and whole brain CMRglc when all 4 groups were included. Conclusions: These results demonstrate that subcortical infarction produces global cerebral hypometabolism, which is related to the clinical status of the patients. In addition, specific frontal lobe hypometabolism also appears to be a feature of subcortical infarction. Taken together, both global and regional effects on cortical function mediate the production of clinical symptoms in patients with subcortical strokes. C1 Univ Calif Davis, Med Ctr, Dept Neurol, Sacramento, CA 95817 USA. Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA USA. Dept Vet Affairs Med Ctr, Martinez, CA USA. Univ Calif San Francisco, Dept Vet Affairs Med Ctr, Magnet Resonance Unit, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Psychiat, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Neurol, San Francisco, CA 94143 USA. RP Jagust, WJ (reprint author), Univ Calif Davis, Med Ctr, Dept Neurol, 4860 Y St,Suite 3700, Sacramento, CA 95817 USA. FU NIA NIH HHS [P01 AG012435-040002, AG12435, P30 AG010129-09, P01 AG012435, AG10129, P30 AG010129] NR 57 TC 65 Z9 71 U1 0 U2 0 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 USA SN 0003-9942 J9 ARCH NEUROL-CHICAGO JI Arch. Neurol. PD JUL PY 1999 VL 56 IS 7 BP 809 EP 814 DI 10.1001/archneur.56.7.809 PG 6 WC Clinical Neurology SC Neurosciences & Neurology GA 214FC UT WOS:000081317100007 PM 10404982 ER PT J AU Fan, XH Strauss, MA Schneider, DP Gunn, JE Lupton, RH Yanny, B Anderson, SF Anderson, JE Annis, J Bahcall, NA Bakken, JA Bastian, S Berman, E Boroski, WN Briegel, C Briggs, JW Brinkmann, J Carr, MA Colestock, PL Connolly, AJ Crocker, JH Csabai, I Czarapata, PC Davis, JE Doi, M Elms, BR Evans, ML Federwitz, GR Frieman, JA Fukugita, M Gurbani, VK Harris, FH Heckman, TM Hennessy, GS Hindsley, RB Holmgren, DJ Hull, C Ichikawa, SI Ichikawa, T Ivezic, Z Kent, S Knapp, GR Kron, RG Lamb, DQ Leger, RF Limmongkol, S Lindenmeyer, C Long, DC Loveday, J MacKinnon, B Mannery, EJ Mantsch, PM Margon, B McKay, TA Munn, JA Nash, T Newberg, HJ Nichol, RC Nicinski, T Okamura, S Ostriker, JP Owen, R Pauls, AG Peoples, J Petravick, D Pier, JR Pordes, R Prosapio, A Rechenmacher, R Richards, GT Richmond, MW Rivetta, CH Rockosi, CM Sandford, D Sergey, G Sekiguchi, M Shimasaku, K Siegmund, WA Smith, JA Stoughton, C Szalay, AS Szokoly, GP Tucker, DL Vogeley, MS Waddell, P Wang, SI Weinberg, DH Yasuda, N York, DG AF Fan, XH Strauss, MA Schneider, DP Gunn, JE Lupton, RH Yanny, B Anderson, SF Anderson, JE Annis, J Bahcall, NA Bakken, JA Bastian, S Berman, E Boroski, WN Briegel, C Briggs, JW Brinkmann, J Carr, MA Colestock, PL Connolly, AJ Crocker, JH Csabai, I Czarapata, PC Davis, JE Doi, M Elms, BR Evans, ML Federwitz, GR Frieman, JA Fukugita, M Gurbani, VK Harris, FH Heckman, TM Hennessy, GS Hindsley, RB Holmgren, DJ Hull, C Ichikawa, SI Ichikawa, T Ivezic, Z Kent, S Knapp, GR Kron, RG Lamb, DQ Leger, RF Limmongkol, S Lindenmeyer, C Long, DC Loveday, J MacKinnon, B Mannery, EJ Mantsch, PM Margon, B McKay, TA Munn, JA Nash, T Newberg, HJ Nichol, RC Nicinski, T Okamura, S Ostriker, JP Owen, R Pauls, AG Peoples, J Petravick, D Pier, JR Pordes, R Prosapio, A Rechenmacher, R Richards, GT Richmond, MW Rivetta, CH Rockosi, CM Sandford, D Sergey, G Sekiguchi, M Shimasaku, K Siegmund, WA Smith, JA Stoughton, C Szalay, AS Szokoly, GP Tucker, DL Vogeley, MS Waddell, P Wang, SI Weinberg, DH Yasuda, N York, DG TI High-redshift quasars found in Sloan Digital Sky Survey commissioning data SO ASTRONOMICAL JOURNAL LA English DT Article DE quasars : general ID LUMINOSITY FUNCTION; ABSORPTION SYSTEMS; MULTICOLOR SURVEY; SPACE DENSITY; SPECTROPHOTOMETRY; Z-GREATER-THAN-4; SPECTROSCOPY; GALAXIES; SPECTRA; OBJECTS AB We present photometric and spectroscopic observations of 15 high-redshift quasars (z > 3.6) discovered from similar to 140 deg(2) of five-color (u', g', r', i', and z') imaging data taken by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. The quasars are selected by their distinctive colors in SDSS multicolor space. Four of the quasars have redshifts higher than 4.6 (z = 4.63, 4.75, 4.90, and 5.00, the latter being the highest redshift quasar yet known). In addition, two previously known z > 4 objects were recovered from the data. The quasars all have i* < 20 and have luminosities comparable to that of 3C 273. The spectra of the quasars have similar features (strong, broad emission lines and substantial absorption blueward of the Ly alpha emission line) seen in previously known high-redshift quasars. Although the photometric accuracy and image quality fail to meet the final survey requirements, our success rate for identifying high-redshift quasars (17 quasars from 27 candidates) is much higher than that of previous multicolor surveys. However, the numbers of high-redshift quasars found is in close accord with the number density inferred from previous surveys. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Chicago, Yerkes Observ, Williams Bay, WI 53191 USA. Apache Point Observ, Sunspot, NM 88349 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Eotvos Lorand Univ, Dept Phys & Complex Syst, H-1117 Budapest, Hungary. Univ Tokyo, Sch Sci, Res Ctr Early Universe, Bunkyo Ku, Tokyo 113003, Japan. Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 113003, Japan. Natl Astron Observ, Mitaka, Tokyo 1818588, Japan. Univ Chicago, Ctr Astron & Astrophys, Chicago, IL 60637 USA. Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan. Inst Adv Study, Princeton, NJ 08540 USA. IIT, Chicago, IL 60616 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. USN Observ, Washington, DC 20392 USA. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. Tohoku Univ, Inst Astron, Aoba Ku, Sendai, Miyagi 9808578, Japan. Merrill Lynch, Chiyoda Ku, Tokyo 100, Japan. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15232 USA. Lucent Technol, Naperville, IL 60566 USA. Rochester Inst Technol, Dept Phys, Rochester, NY 14623 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Fan, XH (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. RI Margon, Bruce/B-5913-2012; Yasuda, Naoki/A-4355-2011; Csabai, Istvan/F-2455-2012; McKay, Timothy/C-1501-2009; OI McKay, Timothy/0000-0001-9036-6150; Csabai, Istvan/0000-0001-9232-9898 NR 47 TC 120 Z9 120 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1999 VL 118 IS 1 BP 1 EP 13 DI 10.1086/300944 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 223WF UT WOS:000081864000001 ER PT J AU Rosati, P Stanford, SA Eisenhardt, PR Elston, R Spinrad, H Stern, D Dey, A AF Rosati, P Stanford, SA Eisenhardt, PR Elston, R Spinrad, H Stern, D Dey, A TI An X-ray-selected galaxy cluster at z=1.26 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : evolution; galaxies : formation; X-rays ID COLOR-MAGNITUDE RELATION; SPECTROPHOTOMETRIC STANDARDS; ELLIPTIC GALAXIES; EVOLUTION AB We report the discovery of an X-ray-luminous galaxy cluster at z = 1.26. RX J0848.9 + 4452 was selected as an X-ray cluster candidate in the ROSAT Deep Cluster Survey on the basis of its spatial extent. Deep optical and near-IR imaging have revealed a galaxy overdensity around the peak of the X-ray emission, with a significant excess of red objects with J-K colors typical of elliptical galaxies at z > 1. Spectroscopic observations at the Reck II Telescope have secured six galaxy redshifts in the range 1.257 < z < 1.267 ([z] = 1.261) within a 35 " radius around the peak X-ray emission. This system lies only 4.'2 away (54.0 h(50)(-1) comoving Mpc, q(0) = 0.5) from the galaxy cluster ClG J0848 + 4453, which was identified at z = 1.273 in a near-IR field galaxy survey and is also known to be X-ray luminous. Assuming that the X-ray emission is entirely due to hot intracluster gas, both these systems have similar rest-frame luminosities L(X) approximate to 1 x 10(44) ergs s(-1) (0.5-2.0 keV band). In combination with our spectrophotometric data for the entire 30 arcmin(2) field, this suggests the presence of a superstructure consisting of two collapsed, possibly virialized, clusters, the first detected to date at z > 1. C1 European So Observ, D-85748 Garching, Germany. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Rosati, P (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. EM prosati@eso.org; adam@igpp.llnl.gov; prme@kromos.jpl.nasa.gov; elston@astro.ufl.edu; spinrad@bigz.berkeley.edu; dan@bigz.berkeley.edu; dey@noao.edu NR 44 TC 144 Z9 144 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1999 VL 118 IS 1 BP 76 EP 85 DI 10.1086/300934 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 223WF UT WOS:000081864000006 ER PT J AU Castro-Tirado, AJ Brandt, S Lund, N Sunyaev, R AF Castro-Tirado, AJ Brandt, S Lund, N Sunyaev, R TI Observations of short-duration X-ray transients by WATCH on Granat SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : flare; stars : pre-main sequence; ISM : individual objects : Chamaeleon I cloud; X-rays : bursts; X-rays : stars ID ALL-SKY SURVEY; STAR-FORMING REGION; FLARE STARS; DARK CLOUD; EMISSION; POPULATION AB During 1990-92, the WATCH all-sky X-ray monitor on Granat discovered six short-duration X-ray transients. In this paper we discuss their possible relationship to peculiar stars. Only one of the fast (few hours) X-ray transients (GRS 1100-771) might be tentatively ascribed to a superflare arising from a young stellar object in the Chamaeleon I star-forming cloud. At the distance of similar to 150 pc, L-x = 1.35 x 10(34) erg s(-1). (8-15 keV), or 2.6 x 10(34) erg s(-1) (0.1-2.4 keV) assuming a thermal spectrum with kT similar to 10 keV, a temperature higher than those previously seen in T Tauri stars (Tsuboi et al. 1998). The peak X-ray luminosity is at least 2 times higher than that derived for the protostar IRS 43 (Grosso et al. 1997) which would make - to our knowledge- the strongest flare ever seen in a YSO. However, the possibility of GRS 1100-771 being an isolated neutron star unrelated to the cloud cannot be excluded, given the relatively large error box provided by WATCH. Regarding the longer duration (similar to 1 day) X-ray transients, none of them seem to be related to known objects. We suggest that the latter are likely to have originated from compact objects in low-mass or high-mass X-ray binaries, similarly to XTE J0421+560. C1 LAEFF, INTA, E-28080 Madrid, Spain. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Danish Space Res Inst, DK-2100 Copenhagen O, Denmark. Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. RP Castro-Tirado, AJ (reprint author), LAEFF, INTA, POB 50727, E-28080 Madrid, Spain. EM ajct@laeff.esa.es OI Castro-Tirado, A. J./0000-0003-2999-3563 NR 56 TC 4 Z9 4 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 JUL PY 1999 VL 347 IS 3 BP 927 EP 931 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 224AK UT WOS:000081873600021 ER PT J AU Miller, RS Westerhoff, S AF Miller, RS Westerhoff, S TI Conceptual design of a next-generation all-sky gamma-ray telescope operating at TeV energies SO ASTROPARTICLE PHYSICS LA English DT Article DE gamma-ray telescopes; cosmic-ray detectors; extensive air showers ID DISCOVERY; DETECTORS AB The next generation all-sky monitor operating at TeV (0.1-30 TeV) energies should be capable of performing a continuous high sensitivity sky survey, and detecting transient sources, such as AGN flares, with high statistical significance on timescales of hours to days. We describe an instrument concept for a large area, wide aperture, TeV ground-based gamma-ray telescope. The conceptual design is comprised of similar to 20 000 1 m(2) scintillator-based pixels arranged in a densely packed mosaic. In addition to fast timing, the dense array of pixels also provides a unique imaging capability; the shower image, the spatial distribution of secondary particles at ground level, can be exploited to identify and reject hadronic backgrounds. The good angular resolution and background rejection capabilities lead directly to high sensitivity, while retaining a large field of view, large effective area, and high duty cycle. An instrument such as the one described here complements the narrow held of view air-Cherenkov telescopes and could, in conjunction with future space-based instruments, extend the energy range for continuous monitoring of the gamma-ray sky from MeV through TeV energies. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. RP Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM richard@lanl.gov NR 31 TC 7 Z9 7 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 EI 1873-2852 J9 ASTROPART PHYS JI Astropart Phys. PD JUL PY 1999 VL 11 IS 3 BP 379 EP 393 DI 10.1016/S0927-6505(99)00007-9 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 215QY UT WOS:000081395100009 ER PT J AU Theiler, J Bloch, J AF Theiler, J Bloch, J TI Multiple concentric annuli for characterizing spatially nonuniform backgrounds SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : data analysis; methods : statistical; stars : imaging; surveys; ultraviolet : stars ID GAMMA-RAY ASTRONOMY; SEARCH; ALEXIS; TRANSIENTS; STATISTICS; COUNT; TIME AB A method is presented for estimating the background at a given location on a sky map by interpolating the estimated background from a set of concentric annuli that surround this location. If the background is nonuniform but smoothly varying, this method provides a more accurate (although less precise) estimate than can be obtained with a single annulus. Several applications of multiannulus background estimation are discussed, including direct testing for point sources in the presence of a nonuniform background, the generation of surrogate maps for characterizing false alarm rates, and precise testing of the null hypothesis that the background is uniform. C1 Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, NIS 2, Los Alamos, NM 87545 USA. RP Theiler, J (reprint author), Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, NIS 2, MS D436, Los Alamos, NM 87545 USA. NR 25 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1999 VL 519 IS 1 BP 372 EP 388 DI 10.1086/307348 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211TH UT WOS:000081177600035 ER PT J AU Coble, K Dragovan, M Kovac, J Halverson, NW Holzapfel, WL Knox, L Dodelson, S Ganga, K Alvarez, D Peterson, JB Griffin, G Newcomb, M Miller, K Platt, SR Novak, G AF Coble, K Dragovan, M Kovac, J Halverson, NW Holzapfel, WL Knox, L Dodelson, S Ganga, K Alvarez, D Peterson, JB Griffin, G Newcomb, M Miller, K Platt, SR Novak, G TI Anisotropy in the cosmic microwave background at degree angular scales: Python V results SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID POWER SPECTRUM; RADIATION; SKY AB Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m off-axis telescope instrumented with a HEMT amplifier-based radiometer having continuum sensitivity from 37 to 45 GHz in two frequency bands. With a 0.degrees 91 x 1.degrees 02 beam, the instrument fully sampled 598 deg(2) of sky, including fields measured during the previous four seasons of Python observations. Interpreting the observed fluctuations as anisotropy in the cosmic microwave background, we place constraints on the angular power spectrum of fluctuations in eight multipole bands up to l similar to 260. The observed spectrum is consistent with both the COBE experiment and previous Python results. There is no significant contamination from known foregrounds. The results show a discernible rise in the angular power spectrum from large (l similar to 40) to small (l similar to 200) angular scales. The shape of the observed power spectrum is not a simple linear rise, but has a sharply increasing slope starting at l similar to 150. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. CALTECH, Pasadena, CA 91125 USA. Fermilab, Batavia, IL 60510 USA. IPAC, Pasadena, CA 91125 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Arizona, Tucson, AZ 85721 USA. Northwestern Univ, Evanston, IL 60208 USA. RP Coble, K (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Peterson, Jeffrey/O-4794-2014; Holzapfel, William/I-4836-2015 OI Peterson, Jeffrey/0000-0003-1340-818X; NR 19 TC 29 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1999 VL 519 IS 1 BP L5 EP L8 DI 10.1086/312093 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211TK UT WOS:000081177800002 ER PT J AU Hui, L AF Hui, L TI Weighing the cosmological energy contents with weak gravitational lensing SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; gravitational lensing; large-scale structure of universe ID LY-ALPHA FOREST; DENSITY DISTRIBUTION; NONLINEAR EVOLUTION; POWER SPECTRUM; FLUCTUATIONS; STATISTICS; GALAXIES AB Using perturbation theory, Bernardeau, Van Waerbeke, & Mellier show that the skewness of the large-scale lensing convergence, or projected mass density, could be used to constrain Omega(m), the matter content of the universe. However, deep weak-lensing field surveys in the near future will likely measure the convergence on small angular scales (less than or similar to 10'), where the signal will be dominated by highly nonlinear fluctuations. We develop a method far computing the small-scale convergence skewness that gives predictions that agree well with existing results from ray-tracing N-body simulations but is significantly faster. We demonstrate that the small-scale convergence skewness is insensitive to the shape and normalization of the primordial (cold dark matter-type) power spectrum, making it dependent almost entirely on the cosmological energy contents. Moreover, nonlinear clustering appears to enhance the differences between predictions of the convergence skewness for a range of models. Hence, in addition to constraining Omega(m), the small-scale convergence skewness from future deep and several degrees wide surveys can be used to differentiate between curvature-dominated and cosmological constant (Lambda)-dominated models, as well as to constrain the equation of state of a quintessence component, thereby distinguishing Lambda from quintessence. Finally, our method can be easily generalized to other measures such as the aperture mass statistics. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM lhui@fnal.gov NR 32 TC 45 Z9 45 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1999 VL 519 IS 1 BP L9 EP L12 DI 10.1086/312095 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211TK UT WOS:000081177800003 ER PT J AU Williams, GG Park, HS Ables, E Band, DL Barthelmy, SD Bionta, R Butterworth, PS Cline, TL Ferguson, DH Fishman, GJ Gehrels, N Hartmann, DH Hurley, K Kouveliotou, C Meegan, CA Ott, L Parker, E Porrata, R AF Williams, GG Park, HS Ables, E Band, DL Barthelmy, SD Bionta, R Butterworth, PS Cline, TL Ferguson, DH Fishman, GJ Gehrels, N Hartmann, DH Hurley, K Kouveliotou, C Meegan, CA Ott, L Parker, E Porrata, R TI LOTIS search for early-time optical afterglows: GRB 971227 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY-BURST; TRANSIENT IMAGING-SYSTEM; EMISSION AB We report on the very early time search for an optical afterglow from GRB 971227 with the Livermore Optical Transient Imaging System (LOTIS). LOTIS began imaging the "original" BATSE error box of GRB 971227 similar to 14 s after the onset of gamma-ray emission. Continuous monitoring of the position throughout the evening yielded a total of 499 images (10 s integration). Analysis of these images revealed no steady optical afterglow brighter than R = 12.3 +/- 0.2 in any single image. Go-addition of the LOTIS images also failed to uncover transient optical emission. In particular, assuming a constant early-time flux, no optical afterglow brighter than R = 14.2 +/- 0.2 was present within the first 1200 s, and no optical afterglow brighter than R = 15.0 +/- 0.2 was present in the first 6.0 hr. Follow-up observations by other groups revealed a likely X-ray afterglow and a possible optical afterglow. Although subsequent deeper observations could not confirm a fading source, we show that these transients are not inconsistent with our present knowledge of the characteristics of gamma-ray burst afterglows. We also demonstrate that with the upgraded thermoelectrically cooled CCDs, LOTIS is capable of either detecting very early time optical afterglow or placing stringent constraints on the relationship between the gamma-ray emission and the longer wavelength afterglow in relativistic blast-wave models. C1 Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Raytheon Syst, Lanham, MD 20706 USA. Calif State Univ Hayward, Dept Phys, Hayward, CA 94542 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Williams, GG (reprint author), Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. RI Barthelmy, Scott/D-2943-2012 NR 43 TC 17 Z9 17 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1999 VL 519 IS 1 BP L25 EP L29 DI 10.1086/312092 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211TK UT WOS:000081177800007 ER PT J AU Bateman, MG Eack, KB Rust, WD Marshall, TC AF Bateman, MG Eack, KB Rust, WD Marshall, TC TI Electrical current along balloon rigging line inside thunderstorms SO ATMOSPHERIC RESEARCH LA English DT Article DE electrical current; balloon; rigging line; thunderstorm ID PRECIPITATION; FIELD AB We have designed a new instrument to measure the current flowing along balloon rigging line during flights through thunderstorms. This instrument was tested in a high voltage facility and used to collect line current data during one balloon flight into a thunderstorm. Using these data, worst-case calculations are made; as such, we claim that they are the upper limits of any alteration (to the measured electric field or particle charge) that may occur, and the real number is Likely much less. It is postulated the rigging-line current could have two separate effects on the measured electric field: (1) reduction of the field due to emission of corona ions, and (2) enhancement of the field due to the insertion of a long thin 'conductor.' Even with current as high as 1 IJ A (the largest measured was around 50-100 nA), these two effects were found to be about -1% and +1%, respectively. Also, the calculated worst-case alteration to charged precipitation measurements is about 0.1 pC. Thus, with proper efforts to make the rigging Line as poor a conductor as possible, it seems that we are justified in stating that these effects are negligible. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Langmuir Lab Atmospher Res, Socorro, NM USA. Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM USA. Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. RP Bateman, MG (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, 977 Explorer Blvd, Huntsville, AL 35806 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUL PY 1999 VL 51 IS 3-4 BP 323 EP 335 DI 10.1016/S0169-8095(99)00017-4 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221QE UT WOS:000081737100012 ER PT J AU Zhang, HL Sampson, DH AF Zhang, HL Sampson, DH TI Relativistic distorted-wave collision strengths and oscillator strengths for the 105 delta n=0 transitions with n=2 in the 81 N-like ions with 12 <= Z <= 92 SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID POSSIBLE N=2-N=3 TRANSITIONS; HIGHLY CHARGED IONS; B-LIKE IONS; C-LIKE IONS; ELECTRON-IMPACT; ATOMIC DATA; CROSS-SECTIONS; EXCITATION; 8-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-92; RATES AB Relativistic distorted-wave collision strengths have been calculated for the 105 Delta n = 0 transitions with n = 2 in the 81 N-like ions with nuclear charge number Z in the range 12 less than or equal to Z less than or equal to 92. The calculations were made for the six final, or scattered, electron energies E' = 0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, where E' is in units of Z(eff)(2) Ry with Z(eff) = Z - 5. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged N-like ions, (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Zhang, HL (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. NR 24 TC 38 Z9 39 U1 0 U2 7 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD JUL PY 1999 VL 72 IS 2 BP 153 EP 216 DI 10.1006/adnd.1999.0812 PG 64 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 232FH UT WOS:000082359900002 ER PT J AU Fontes, CJ Sampson, DH Zhang, HL AF Fontes, CJ Sampson, DH Zhang, HL TI Fully relativistic distorted-wave cross sections for electron impact ionization from the 2s, 2p(1/2), and 2p(3/2) subshells in ions with Z-N >= 3, Z <= 92, and N <= 12 SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID HIGHLY CHARGED IONS; ATOMS AB A fully relativistic distorted-wave method has been used to calculate a large number of cross sections for electron impact ionization from the 2s, 2p(1/2), and 2p(3/2) subshells of ions with Z - N greater than or equal to 4 (that is, ions that are at least four times ionized), where Z is the nuclear charge and N is the initial number of bound electrons per ion. In the special case of hydrogenic ions (N = 1), Z = 4 is also treated. Furthermore, a wide range of ions were considered, limited only by the additional conditions Z less than or equal to 92 and N less than or equal to 12. The generalized Breit interaction between bound and free electrons was included when significant, but this was found to occur only for Z greater than or similar to 42 and had a maximum effect of only 13%. The results have been expressed in a convenient way, and fits have been made that allow one to readily obtain cross sections and rate coefficients for all ions in the above ranges of Z and N. (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Fontes, CJ (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 11 Z9 11 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD JUL PY 1999 VL 72 IS 2 BP 217 EP 238 DI 10.1006/adnd.1999.0814 PG 22 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 232FH UT WOS:000082359900003 ER PT J AU An, WJ Zlatanova, J Leuba, SH van Holde, K AF An, WJ Zlatanova, J Leuba, SH van Holde, K TI The site of binding of linker histone to the nucleosome does not depend upon the amino termini of core histones SO BIOCHIMIE LA English DT Article DE core histone tails; H3 tails; linker histone; nucleosome ID SCANNING FORCE MICROSCOPY; RIBOSOMAL-RNA GENE; CHROMATIN STRUCTURE; XENOPUS-BOREALIS; DNA; TRANSCRIPTION; ACETYLATION; TAILS; H-1; H1 AB Using nucleosomes reconstituted on a defined sequence of DNA, we have investigated the question as to whether the N-terminal tails of core histones play a role in determining the site of binding of a linker histone. Reconstitutes used histone cores of three types: intact, lacking the N-terminal H3 tails, or lacking all tails. In each case the same, single defined position for the histone core was observed, using high-resolution mapping. The affinity for binding of linker histone H1 degrees was highest for the intact cores, lowest for the tailless cores. However, the location of the linker histone, as judged by micrococcal nuclease protection, was exactly the same in each-case, an asymmetric site of about 17 bp to one side of the core particle DNA. (C) 1999 Societe francaise de biochimie et biologie moleculaire / Editions scientifiques et medicales Elsevier SAS. C1 Oregon State Univ, Dept Biochem & Biophys, Corvallis, OR 97331 USA. Bulgarian Acad Sci, Inst Genet, BU-1113 Sofia, Bulgaria. RP Zlatanova, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Zlatanova, Jordanka/B-3273-2009 FU FIC NIH HHS [TW00568]; NIGMS NIH HHS [GM50276] NR 41 TC 8 Z9 8 U1 0 U2 1 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 0300-9084 J9 BIOCHIMIE JI Biochimie PD JUL PY 1999 VL 81 IS 7 BP 727 EP 732 DI 10.1016/S0300-9084(99)80130-8 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 236AG UT WOS:000082575600005 PM 10492019 ER PT J AU Borovina, TA Nazipova, NN Overbeek, R Gelfand, MS AF Borovina, TA Nazipova, NN Overbeek, R Gelfand, MS TI Statistical analysis and prediction of prokaryote ribosomal binding sites SO BIOFIZIKA LA Russian DT Article DE bacteria; ribosomal binding sites; algorithm for recognition ID TRANSLATIONAL INITIATION SITES; ESCHERICHIA-COLI; MESSENGER-RNA; IDENTIFICATION AB An algorithm for recognition of prokaryotic ribosomal binding sites is suggested. The parameter library contains weight matrices for mapping of gene starts in various bacterial genomes. Comparison of. the ribosome binding starts in different taxonomic groups demonstrates that the signals in Gram-positive bacteria are stronger than in Gram-negative bacteria, and in particular, Enterobacteria. The recognition matrices are available by e-mail misha@imb.imb.ac.ru. C1 Russian Acad Sci, Inst Math Problems Biol, Pushchino 142292, Moscow Region, Russia. Argonne Natl Lab, Argonne, IL 60439 USA. Russian Acad Sci, Inst Prot Res, Pushchino 142292, Moscow Region, Russia. RP Borovina, TA (reprint author), Russian Acad Sci, Inst Math Problems Biol, Pushchino 142292, Moscow Region, Russia. RI Gelfand, Mikhail/F-3425-2012; Nazipova, Nafisa/N-4270-2013; Borovina, Tatiana/C-4200-2014 OI Nazipova, Nafisa/0000-0003-0162-7967; Borovina, Tatiana/0000-0002-3660-8849 NR 25 TC 0 Z9 0 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0006-3029 J9 BIOFIZIKA+ JI Biofizika PD JUL-AUG PY 1999 VL 44 IS 4 BP 611 EP 619 PG 9 WC Biophysics SC Biophysics GA 252NC UT WOS:000083506700004 PM 10544809 ER PT J AU Hooker, B AF Hooker, B TI Trends in transgenics - Two crops, one plant - Lab uses plants to produce recombinant human proteins and industrial enzymes SO BIOPHARM-THE APPLIED TECHNOLOGIES OF BIOPHARMACEUTICAL DEVELOPMENT LA English DT Article C1 Battelle Pacific NW Div, Richland, WA 99352 USA. RP Hooker, B (reprint author), Battelle Pacific NW Div, Richland, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ADVANSTAR COMMUNICATIONS PI DULUTH PA 131 W FIRST ST, DULUTH, MN 55802 USA SN 1040-8304 J9 BIOPHARM-APPL T BIO JI Biopharm-Appl Technol. Biopharm. Dev. PD JUL PY 1999 VL 12 IS 7 BP 29 EP 30 PG 2 WC Biotechnology & Applied Microbiology; Pharmacology & Pharmacy SC Biotechnology & Applied Microbiology; Pharmacology & Pharmacy GA 220FA UT WOS:000081652800024 ER PT J AU Howes, BD Schiodt, CB Welinder, KG Marzocchi, MP Ma, JG Zhang, J Shelnutt, JA Smulevich, G AF Howes, BD Schiodt, CB Welinder, KG Marzocchi, MP Ma, JG Zhang, J Shelnutt, JA Smulevich, G TI The quantum mixed-spin heme stale of barley peroxidase: A paradigm for class III peroxidases SO BIOPHYSICAL JOURNAL LA English DT Article ID CYTOCHROME-C PEROXIDASE; RESONANCE RAMAN-SPECTRA; SITE-DIRECTED MUTAGENESIS; HORSERADISH-PEROXIDASE; PHOTOSYNTHETIC BACTERIA; ELECTRONIC ABSORPTION; PROTEIN INTERACTIONS; ANGSTROM RESOLUTION; FERRICYTOCHROME C'; HYDROGEN-PEROXIDE AB Electronic absorption and resonance Raman (RR) spectra of the ferric form of barley grain peroxidase (BP 1) at various pH values, at both room temperature and 20 K, are reported, together with electron paramagnetic resonance spectra at 10 K. The ferrous forms and the ferric complex with fluoride have also been studied. A quantum mechanically mixed-spin (QS) state has been identified. The QS heme species coexists with 6- and 5-cHS hemes; the relative populations of these three spin states are found to be dependent on pH and temperature. However, the QS species remains in all cases the dominant heme spin species. Barley peroxidase appears to be further characterized by a splitting of the two vinyl stretching modes, indicating that the vinyl groups are differently conjugated with the porphyrin. An analysis of the currently available spectroscopic data for proteins from all three peroxidase classes suggests that the simultaneous occurrence of the QS heme state as well as the splitting of the two vinyl stretching modes is confined to class III enzymes. The former point is discussed in terms of the possible influences of heme deformations on heme spin state. It is found that moderate saddling alone is probably not enough to cause the QS state, although some saddling may be necessary for the QS state. C1 Univ Florence, Dipartimento Chim, I-50121 Florence, Italy. Univ Copenhagen, Dept Prot Chem, DK-1353 Copenhagen K, Denmark. Univ Aalborg, Biotechnol Lab, DK-9000 Aalborg, Denmark. Sandia Natl Labs, Mat Theory & Computat Dept, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Smulevich, G (reprint author), Univ Florence, Dipartimento Chim, Via G Capponi 9, I-50121 Florence, Italy. RI smulevich, giulietta/A-6510-2008; Shelnutt, John/A-9987-2009; OI Shelnutt, John/0000-0001-7368-582X; Smulevich, Giulietta/0000-0003-3021-8919 NR 59 TC 57 Z9 57 U1 2 U2 7 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JUL PY 1999 VL 77 IS 1 BP 478 EP 492 DI 10.1016/S0006-3495(99)76905-5 PG 15 WC Biophysics SC Biophysics GA 214RQ UT WOS:000081341700039 PM 10388773 ER PT J AU Tara, S Straatsma, TP McCammon, JA AF Tara, S Straatsma, TP McCammon, JA TI Mouse acetylcholinesterase unliganded and in complex with huperzine A: A comparison of molecular dynamics simulations SO BIOPOLYMERS LA English DT Article DE molecular dynamics simulations; acetylcholinesterase; huperzine A; active site gorge; side channel; backdoor; gating ID ACTIVE-SITE GORGE; NUCLEIC-ACIDS; PROTEINS; SYSTEMS; BINDING; PROGRAM AB A 1 ns molecular dynamics simulation of unliganded mouse acetylcholinesterase (AChE) is compared to a previous simulation of mouse AChE complexed with huperzine A (HupA). Several common features are observed. In both simulations the active site gorge fluctuates in size during the I ns trajectory and is completely pinched off several times. Many of the residues in the gorge that formed hydrogen bonds with HupA in the simulation of the complex now form hydrogen bonds with other protein residues and water molecules in the gorge. The opening of a "backdoor" entrance to the active site that was Sound in the simulation of the complex is also observed in the unliganded simulation. Differences between the two simulations include overall lower structural rms deviations for residues in the gorge in the unliganded simulation a smaller diameter of the gorge in the absence of HupA, and the disappearance of a side channel that was frequently present in the liganded simulation The differences between the two simulations can be attributed in pal?, to the interaction of AChE with HupA. (C) 1999 John Wiley & Sons, Inc. C1 Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. Pacific NW Lab, Environm Mol Sci Lab, High Performance Computat Chem Grp, Richland, WA 99352 USA. Univ Calif San Diego, Dept Pharmacol, La Jolla, CA 92093 USA. RP Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. EM stara@ucsd.edu NR 24 TC 29 Z9 29 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0006-3525 EI 1097-0282 J9 BIOPOLYMERS JI Biopolymers PD JUL PY 1999 VL 50 IS 1 BP 35 EP 43 DI 10.1002/(SICI)1097-0282(199907)50:1<35::AID-BIP4>3.0.CO;2-6 PG 9 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 197JZ UT WOS:000080362800004 PM 10341665 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Kinetic study of the concentration dependence of the mass transfer rate coefficient in anion-exchange chromatography of bovine serum albumin SO BIOTECHNOLOGY PROGRESS LA English DT Article ID LIQUID-PHASE ADSORPTION; SURFACE-DIFFUSION; PERFUSION CHROMATOGRAPHY; INTRAPARTICLE CONVECTION; CELLULOSE TRIACETATE; LIGHT-SCATTERING; PORE DIFFUSION; PERFORMANCE; PROTEINS; SEPARATION AB The experimental results of a previous study of the mass transfer kinetics of bovine serum albumin (BSA) in ion-exchange chromatography under nonlinear conditions are reevaluated. The analysis of the concentration dependence of the lumped mass-transfer rate coefficient (k(m,L)) provides information on the kinetics of axial dispersion, fluid-to-particle mass transfer, intraparticle mass transfer, and adsorption/desorption. The new analysis shows that the contribution of intraparticle mass transfer is the dominant one. Similar to km,L, the surface diffusivity (D-s) of BSA increases with increasing concentration. The linear concentration dependence of k(m,L) seems to originate in a similar dependence of D-s. The use of an heterogeneous-surface model for the anion-exchange resin provides an explanation of the positive concentration dependence of D-s. This work illustrates how frontal analysis data can be used for a detailed investigation of the kinetics of mass transfer between the phases of a chromatographic column, in addition to its conventional use in the determination of the thermodynamic characteristics of the phase equilibrium. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 52 TC 40 Z9 40 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD JUL-AUG PY 1999 VL 15 IS 4 BP 740 EP 752 DI 10.1021/bp990062x PG 13 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA 226JN UT WOS:000082017000019 PM 10441366 ER PT J AU Martin, EA Gaskell, M Carver, TL Turteltaub, K Al-Azzawi, F White, INH AF Martin, EA Gaskell, M Carver, TL Turteltaub, K Al-Azzawi, F White, INH TI Analysis of tamoxifen-DNA and protein adducts in humans and rats by accelerator mass spectrometry SO BRITISH JOURNAL OF CANCER LA English DT Meeting Abstract C1 Univ Leicester, MRC, Toxicol Unit, Leicester LE1 9HN, Leics, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Univ Leicester, Dept Obstet & Gynecol, Leicester LE1 5WW, Leics, England. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CHURCHILL LIVINGSTONE PI EDINBURGH PA JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH EH1 3AF, MIDLOTHIAN, SCOTLAND SN 0007-0920 J9 BRIT J CANCER JI Br. J. Cancer PD JUL PY 1999 VL 80 SU 2 MA P276 BP 97 EP 97 PG 1 WC Oncology SC Oncology GA 225JR UT WOS:000081955000373 ER PT J AU Verkasalo, PK Pukkala, E Stevens, RG Ojamo, M Rudanko, SL AF Verkasalo, PK Pukkala, E Stevens, RG Ojamo, M Rudanko, SL TI Inverse association between breast cancer incidence and degree of visual impairment in Finland SO BRITISH JOURNAL OF CANCER LA English DT Article DE blindness; breast neoplasms; epidemiology; medical record linkage; melatonin; vision disorders ID MELATONIN AB A total of 10 935 women with visual impairment were identified from the Finnish Register of Visual impairment and followed up for cancer through the Finnish Cancer Registry for years 1983-1996, Breast cancer risk decreased by degree of visual impairment (P for trend 0.04) which suggests a dose-response relationship between visible light and breast cancer risk. C1 Univ Helsinki, Dept Publ Hlth, FIN-00014 Helsinki, Finland. Natl Publ Hlth Inst, Dept Environm Hlth, FIN-70701 Kuopio, Finland. Finnish Canc Registry, FIN-00170 Helsinki, Finland. Pacific NW Lab, Richland, WA 99352 USA. Finnish Registry Visual Impairment, FIN-00510 Helsinki, Finland. RP Verkasalo, PK (reprint author), Radcliffe Infirm, Imperial Canc Res Fund, Canc Epidemiol Unit, Gibson Bldg, Oxford OX2 6HE, England. NR 10 TC 77 Z9 79 U1 0 U2 1 PU CHURCHILL LIVINGSTONE PI EDINBURGH PA JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH EH1 3AF, MIDLOTHIAN, SCOTLAND SN 0007-0920 J9 BRIT J CANCER JI Br. J. Cancer PD JUL PY 1999 VL 80 IS 9 BP 1459 EP 1460 DI 10.1038/sj.bjc.6690544 PG 2 WC Oncology SC Oncology GA 212RL UT WOS:000081230000023 PM 10424751 ER PT J AU Crawley, D Aho, I AF Crawley, D Aho, I TI Building environmental assessment methods: applications and development trends SO BUILDING RESEARCH AND INFORMATION LA English DT Article DE environmental assessment; green buildings; life cycle assessment; building performance; Green Building Challenge AB The construction and property sector has seen the development of a number of methods for evaluating the 'greenness' of buildings in the 1990s - both for new designs and existing buildings, These range from very detailed life cycle assessment methods, which account for all the embodied and operational environmental impacts of building materials, to higher level environmental impact assessment methods, which evaluate the broader implications of the building's impact on the environment. In between these two are environmental assessment methods such as BREEAM, BEPAC, LEED, and GBA. In this paper, we discuss the potential market applications of these systems and compare and contrast several of the major environmental assessment methods. C1 US DOE, Washington, DC 20585 USA. Motiva, FIN-02151 Espoo, Finland. RP Crawley, D (reprint author), US DOE, 1000 Independence Ave SW, Washington, DC 20585 USA. NR 7 TC 96 Z9 97 U1 4 U2 23 PU ROUTLEDGE PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0961-3218 J9 BUILD RES INF JI Build. Res. Informat. PD JUL-OCT PY 1999 VL 27 IS 4-5 BP 300 EP 308 PG 9 WC Construction & Building Technology SC Construction & Building Technology GA 226JG UT WOS:000082016400010 ER PT J AU Balasundaram, R Jiang, SY Belak, J AF Balasundaram, R Jiang, SY Belak, J TI Structural and rheological properties of n-decane confined between graphite surfaces SO CHEMICAL ENGINEERING JOURNAL LA English DT Article DE molecular dynamics; confined fluid; rheology ID MOLECULAR-DYNAMICS SIMULATION; SIMPLE FLUIDS; LIQUID-FILMS; SHEAR-FLOW; LUBRICATION; FRICTION; ALKANES; MOTION; PORES; SLIP AB We report a constant-volume and constant-pressure molecular dynamics study of the fluid structure. flow boundary condition, and shear viscosity of n-decane confined between graphite surfaces under various shear rates at 480 K using an anisotropic united atom model. The effect of surface corrugation, wall-fluid interaction strength, and load on these properties is investigated in this work. Our results show that the surface corrugation has a pronounced effect on rheological properties, but not on structural and orientational properties at the temperature studied. The shear thinning behavior of the confined fluids is observed for all cases under the shear rates studied. Our results also show that the velocity profile deviates more from the perfect linear profile with increasing surface corrugation, wall-fluid interaction strength, shear rate, and normal load. Slip occurs throughout the range of parameters studied. The fluid layers near the walls could be locked to each other even though slip occurs at the solid-fluid interface. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Kansas State Univ, Dept Chem Engn, Manhattan, KS 66056 USA. Lawrence Livermore Natl Lab, Condensed Matter Phys Div, Livermore, CA 94551 USA. RP Jiang, SY (reprint author), Kansas State Univ, Dept Chem Engn, Durland Hall, Manhattan, KS 66056 USA. EM sjiang@pluto.cheme.ksu.edu NR 54 TC 15 Z9 15 U1 2 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1385-8947 J9 CHEM ENG J JI Chem. Eng. J. PD JUL PY 1999 VL 74 IS 1-2 BP 117 EP 127 DI 10.1016/S1385-8947(99)00063-7 PG 11 WC Engineering, Environmental; Engineering, Chemical SC Engineering GA 219GH UT WOS:000081599200013 ER PT J AU Dixon, DA Feller, D AF Dixon, DA Feller, D TI Computational chemistry and process design SO CHEMICAL ENGINEERING SCIENCE LA English DT Article; Proceedings Paper CT 15th International Symposium on Chemical Reaction Engineering (ISCRE 15) CY SEP 13-16, 1998 CL NEWPORT BEACH, CA SP NSF, DOE, Mobil Corp DE computational chemistry; molecular orbital theory; density functional theory; parallel processing; basis sets; chemical processing ID MOLECULAR WAVE-FUNCTIONS; BENCHMARK CALCULATIONS; BASIS-SETS; ENERGIES; BORON; GAS; APPROXIMATION; ENERGETICS; HYDROGEN; 1ST-ROW AB The use of computational chemistry to address issues relative to process design is discussed. The need for efficient software for massively parallel architectures is described. Methods to predict the electronic structure of molecules are described for the molecular orbital and density functional theory approaches. The capabilities of the computational chemistry software NWChem and Ecce developed in the Environmental Molecular Sciences Laboratory are discussed. Two examples of electronic structure calculations are given. The first shows that one can now make extremely accurate predictions of the thermochemistry of small molecules if one carefully considers all of the details such as zero point energies, core-valence corrections, and relativistic corrections. The second example shows how more approximate computational methods, still based on high level electronic structure calculations, can be used to address a complex waste processing problem at a Department of Energy nuclear production facility. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dixon, DA (reprint author), Pacific NW Natl lab, Environm Mol Sci Lab, Battelle Blvd,POB K1-83, Richland, WA 99352 USA. EM david.dixon@pnl.gov NR 61 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0009-2509 EI 1873-4405 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD JUL PY 1999 VL 54 IS 13-14 BP 1929 EP 1939 DI 10.1016/S0009-2509(98)00510-7 PG 11 WC Engineering, Chemical SC Engineering GA 206XR UT WOS:000080906200002 ER PT J AU Tonkovich, AY Zilka, JL LaMont, MJ Wang, Y Wegeng, RS AF Tonkovich, AY Zilka, JL LaMont, MJ Wang, Y Wegeng, RS TI Microchannel reactors for fuel processing applications. I. Water gas shift reactor SO CHEMICAL ENGINEERING SCIENCE LA English DT Article; Proceedings Paper CT 15th International Symposium on Chemical Reaction Engineering (ISCRE 15) CY SEP 13-16, 1998 CL NEWPORT BEACH, CALIFORNIA SP NSF, DOE, Mobil Corp DE fuel processor; water gas shift reaction; microchannel reactor; microtechnology; process miniaturization; engineered-monolithic catalyst AB The water gas shift reactor is one of the critical components of a multi-reactor fuel processing system that supports distributed energy production through the use of a fuel cell. The water gas shift reaction converts carbon monoxide (produced in the primary conversion stage of the fuel processor) and water to carbon dioxide and hydrogen. The water gas shift reaction has slow observed kinetics, with multiple-second contact times, which are cited in fixed-bed reactors. The intrinsic reaction kinetics, however, are measured to be fast, with millisecond contact times, which enables miniaturized deployment in a microchannel reactor. Microchannel reactors reduce heat and mass transport limitations far reactions, and thus facilitate exploiting fast intrinsic reaction kinetics, ie. high effectiveness factors. The implications of this work suggest that a water gas shift reactor for a fuel processor (and other applications) will approach sizes one-to-two orders of magnitude smaller than conventional processing hardware. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Tonkovich, AY (reprint author), Pacific NW Natl Lab, MSIN K8-93,Battelle Blvd,POB 999, Richland, WA 99352 USA. RI Wang, Yong/C-2344-2013 NR 10 TC 110 Z9 115 U1 4 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD JUL PY 1999 VL 54 IS 13-14 BP 2947 EP 2951 DI 10.1016/S0009-2509(98)00346-7 PG 5 WC Engineering, Chemical SC Engineering GA 206XR UT WOS:000080906200106 ER PT J AU Gracias, DH Zhang, D Lianos, L Ibach, W Shen, YR Somorjai, GA AF Gracias, DH Zhang, D Lianos, L Ibach, W Shen, YR Somorjai, GA TI A study of the glass transition of polypropylene surfaces by sum-frequency vibrational spectroscopy and scanning force microscopy SO CHEMICAL PHYSICS LA English DT Article ID POLYSTYRENE FILMS; POLYETHYLENE AB Sum-frequency generation (SFG) vibrational spectroscopy and scanning force microscopy (SFM) were used to probe structural changes of atactic polypropylene (APP) and isotactic polypropylene (IPP) surfaces in the glass transition. The results indicate that below the glass transition, the surface polymer chains are better oriented with the CH2 groups pointing outward and the surface elastic modulus is higher. The SFG and SFM results correlate well in the transition towards the glass phase. No discernible difference between the glass transition temperatures of the bulk and surface was observed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Gracias, David/A-1942-2010 OI Gracias, David/0000-0003-2735-4725 NR 24 TC 59 Z9 62 U1 3 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUL 1 PY 1999 VL 245 IS 1-3 BP 277 EP 284 DI 10.1016/S0301-0104(99)00043-9 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 229WP UT WOS:000082219000022 ER PT J AU Divine, KK Lewis, JL Grant, PG Bench, G AF Divine, KK Lewis, JL Grant, PG Bench, G TI Quantitative particle-induced X-ray emission imaging of rat olfactory epithelium applied to the permeability of rat epithelium to inhaled aluminum SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Article ID NUCLEAR MICROPROBE; MICROANALYSIS; LIVERMORE; TRANSPORT; PACKAGE; BRAIN; VIRUS; PIXE AB Neurotoxicity from chronic metal inhalation has been suggested as an underlying contributor to late-developing neurodegenerative diseases that have symptoms similar to Alzheimer's and Parkinson's syndromes. If inhaled metals contribute to pathogenesis of these diseases, identifying, localizing, and quantitating metal deposition(s) within specific target regions of the central nervous system will be critical to our understanding of the mechanisms. Standard analytical techniques used to date require exposure to extremely high concentrations of metals to meet analytical detection limits in small tissue areas. The relevance to lower-dose environmentally relevant exposures and potential protective barriers is therefore questionable. The feasibility of microbeam particle-induced X-ray emission is investigated as a method for rapidly scanning tissues to study the inhalation of metals, nasal permeability, and central nervous system deposition. The optimal beam spot and analysis time used to image the rat olfactory epithelium to facilitate the rapid detection of aluminum localizations were determined. Measurements of aluminum localizations in rat olfactory bulb and brain sections are also presented. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. Lovelace Resp Res Inst, Albuquerque, NM 87185 USA. Univ New Mexico, Ctr Populat Hlth, Albuquerque, NM 87131 USA. RP Bench, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, L-397, Livermore, CA 94550 USA. FU NIEHS NIH HHS [ESO9705] NR 21 TC 19 Z9 19 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0893-228X J9 CHEM RES TOXICOL JI Chem. Res. Toxicol. PD JUL PY 1999 VL 12 IS 7 BP 575 EP 581 DI 10.1021/tx9900268 PG 7 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA 219JC UT WOS:000081603300005 PM 10409396 ER PT J AU Chakrabarti, S Gentle, AP Kheyfets, A Miller, WA AF Chakrabarti, S Gentle, AP Kheyfets, A Miller, WA TI Geodesic deviation in Regge calculus SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article AB Geodesic deviation is the most basic manifestation of the influence of gravitational fields on matter. We investigate geodesic deviation within the framework of Regge calculus, and compare the results with the continuous formulation of general relativity on two different levels. We show that the continuum and simplicial descriptions coincide when the cumulative effect of the Regge contributions over an infinitesimal element of area is considered. This comparison provides a quantitative relation between the curvature of the continuous description and the deficit angles of Regge calculus. The results presented might also be of help in developing generic ways of including matter terms in the Regge equations. C1 N Carolina State Univ, Dept Math, Raleigh, NC 27695 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Chakrabarti, S (reprint author), N Carolina State Univ, Dept Math, Box 8205, Raleigh, NC 27695 USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD JUL PY 1999 VL 16 IS 7 BP 2381 EP 2391 DI 10.1088/0264-9381/16/7/315 PG 11 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 221BR UT WOS:000081704700018 ER PT J AU Kostiuk, LW Shepherd, IG Bray, KNC AF Kostiuk, LW Shepherd, IG Bray, KNC TI Experimental study of premixed turbulent combustion in opposed streams. Part III - Spatial structure of flames SO COMBUSTION AND FLAME LA English DT Article ID FLOW FIELD; EXTINCTION AB The local scalar statistics of premixed flames in turbulent opposed streams has been studied by sheet laser tomography. The statistics collected on these flame edges provide information on the mean flame position, and the mean and standard deviations of local flamelet orientation and curvature. Emphasis is given to how these parameters vary through the flame brush as the flames are pushed toward extinction. The flames are essentially planar in the mean and the probability density function (pdf) of flamelet orientation is symmetric about this mean orientation. The standard deviation of flame angle is essentially constant throughout the flame brush, but varies strongly at the leading and trailing flame edges. The mean curvature of these flame is positive (i.e., concave to products) at the leading edge of the flame and negative at its trailing edge. Similar to the flame angle, the standard deviation of flame curvature is also constant throughout most of the central portion of the flame brush. As the mean nozzle exit velocity and the turbulence intensity are increased to bring the flame nearer to extinction, the individual flame brushes thicken as much as 50%. The standard deviations of flame angle and curvature also increase but more modestly. An unexpected result of the data collected is the differences between the upper and lower flames, which is probably an effect of buoyancy. The lower flame is consistently and significantly more wrinkled than the upper flame, resulting in the lower brush being thicker by as much as 25% and having larger standard deviations of flame angle and curvature than the upper flame. (C) 1999 by The Combustion Institute. C1 Univ Alberta, Dept Mech Engn, Combust & Environm Grp, Edmonton, AB T6G 2G8, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Combust & Fluid Mech Grp, Div Energy & Environm, Berkeley, CA 94720 USA. Univ Cambridge, Dept Engn, Cambridge CB3 1PZ, England. RP Kostiuk, LW (reprint author), Univ Alberta, Dept Mech Engn, Combust & Environm Grp, Edmonton, AB T6G 2G8, Canada. NR 22 TC 29 Z9 30 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 1999 VL 118 IS 1-2 BP 129 EP 139 DI 10.1016/S0010-2180(98)00155-2 PG 11 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 195BP UT WOS:000080229500011 ER PT J AU Im, HG Chen, JH Chen, JY AF Im, HG Chen, JH Chen, JY TI Chemical response of methane air diffusion flames to unsteady strain rate SO COMBUSTION AND FLAME LA English DT Article ID EXTINCTION; HYDROGEN AB Effects of unsteady strain rate on the response of methane/air diffusion flames are studied numerically. The numerical simulations are carried out for the finite-domain opposed flow configuration in which the nozzle exit velocities are prescribed as a function of time. The chemical kinetics is computed with the GRI mechanism v2.11 including NO, in methane/air combustion. The response of individual species to monochromatic oscillation in strain rate with various frequencies reveals that the fluctuation of slow species, such as CO and NO,, is quickly suppressed as the flow time scale decreases. Furthermore, it is observed that the maximum CO concentration is very insensitive to the variation in the scalar dissipation rate. It is also demonstrated that, for high-frequency oscillations, the scalar dissipation rate is a more appropriate parameter than strain rate to characterize the unsteady flame behavior. An extinction event due to an abrupt imposition of high strain rates is simulated by an impulsive velocity with various frequencies. For a fast impulse, a substantial overshoot in NO, concentration is observed immediately after extinction. The overall fuel burning rate shows a weak response to the variation in characteristic unsteady time scale, while the emission indices for NO, show a monotonic decay in response as the impulse frequency increases. (C) 1999 by The Combustion Institute. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Im, HG (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RI Im, Hong/J-4317-2012 NR 25 TC 41 Z9 42 U1 2 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 1999 VL 118 IS 1-2 BP 204 EP 212 DI 10.1016/S0010-2180(98)00153-9 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 195BP UT WOS:000080229500017 ER PT J AU Echekki, T Chen, JH AF Echekki, T Chen, JH TI Analysis of the contribution of curvature to premixed flame propagation SO COMBUSTION AND FLAME LA English DT Article ID TURBULENT C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Echekki, T (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. RI Echekki, Tarek/C-7394-2009; OI Echekki, Tarek/0000-0002-0146-7994 NR 12 TC 64 Z9 64 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 1999 VL 118 IS 1-2 BP 308 EP 311 DI 10.1016/S0010-2180(99)00006-1 PG 4 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 195BP UT WOS:000080229500026 ER PT J AU Plummer, DW Dalton, LJ Peter, FJ AF Plummer, DW Dalton, LJ Peter, FJ TI The recodable locking device SO COMMUNICATIONS OF THE ACM LA English DT Article C1 Sandia Natl Labs, Electromech Engn Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, High Integr Software Syst Engn Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, High Integr Syst Program, Albuquerque, NM 87185 USA. RP Plummer, DW (reprint author), Sandia Natl Labs, Electromech Engn Dept, POB 5800, Albuquerque, NM 87185 USA. NR 1 TC 2 Z9 2 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0001-0782 J9 COMMUN ACM JI Commun. ACM PD JUL PY 1999 VL 42 IS 7 BP 83 EP 87 DI 10.1145/306549.306585 PG 5 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 211EJ UT WOS:000081146700020 ER PT J AU Zhang, DS Kouri, DJ Hoffman, DK Gunaratne, GH AF Zhang, DS Kouri, DJ Hoffman, DK Gunaratne, GH TI Distributed approximating functional treatment of noisy signals SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID DYNAMICS AB Based on their so-called "well-tempered" property, distributed approximating functionals (DAFs) are shown to be very good data filters, and consequently, they have many potential applications in all fields of engineering and the natural sciences. In this paper, a periodic extension of a noisy signal is proposed to generate a "pseudo-signal" in the infinite domain, enabling the use of noncausal, zero-phase window filters that require a knowledge of the signal in the extended domain. The extended signal is also useful for the application of fast Fourier transforms tin which the preferred number of sampled data points is a power of 2). The most attractive feature of the method is that it introduces little aliasing between the original and true signal. The resulting extended signal is then filtered by using DAFs as low pass filters under the assumption that the true signal is bandwidth limited and most of the noise components are in the high frequency region. A "signature" based on computing the root-mean-square value of the filtered signal is introduced to indicate when the high frequency noise has been eliminated with the choice of the DAF parameters. To illustrate the usefulness of the present algorithm, two noisy signal examples are periodically extended and filtered using DAFs. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Inst Fundamental Studies, Kandy, Sri Lanka. RP Zhang, DS (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. NR 12 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD JUL PY 1999 VL 120 IS 1 BP 1 EP 12 DI 10.1016/S0010-4655(99)00215-5 PG 12 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 226NQ UT WOS:000082026400001 ER PT J AU Rider, WJ AF Rider, WJ TI An adaptive Riemann solver using a two-shock approximation SO COMPUTERS & FLUIDS LA English DT Article ID GODUNOV-TYPE METHODS; HYPERBOLIC CONSERVATION-LAWS; MIE-GRUNEISEN EQUATION; THERMODYNAMIC STABILITY; GAS-DYNAMICS; FLUID-FLOW; GASDYNAMICS; SCHEMES; SYSTEMS; STATE AB An approximate Riemann solver is developed using a linear approximation for the shock velocity in particle velocity. The approximation is a second-order Taylor expansion for the pressure in velocity. Bounds ape established for the values of the linear coefficient while assuring a physical entropy satisfying solution. This is done rigorously for an ideal gas and is incorporated in a nonlinear function that recovers both the weak and strong shock limits. Extensions to more general equations of state are discussed through several examples (JWL and Mie-Gruneisen). For strong rarefactions, an exponential function is used for the wave curve that has appropriate asymptotic properties and is continuous to second-order with the shock curve at the centering point for the Riemann problem. This provides the Riemann solver with an adaptive character with an inexpensive, but accurate approximation for weak discontinuities, and asymptotically appropriate approximations for strong discontinuities. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Hydrodynam Methods Grp, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Hydrodynam Methods Grp, Mail Stop D413, Los Alamos, NM 87545 USA. EM wjr@lanl.gov NR 36 TC 19 Z9 19 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 EI 1879-0747 J9 COMPUT FLUIDS JI Comput. Fluids PD JUL PY 1999 VL 28 IS 6 BP 741 EP 777 DI 10.1016/S0045-7930(98)00033-4 PG 37 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 191UQ UT WOS:000080040300001 ER PT J AU Xu, TF Pruess, K Brimhall, G AF Xu, TF Pruess, K Brimhall, G TI An improved equilibrium-kinetics speciation algorithm for redox reactions in variably saturated subsurface flow systems SO COMPUTERS & GEOSCIENCES LA English DT Article DE speciation algorithm; equilibrium-kinetics; redox reactions; variably saturated subsurface flow; reactive transport ID MODEL DEVELOPMENT; TRANSPORT MODEL; POROUS-MEDIA; FLUID-FLOW; GROUNDWATER; DISSOLUTION; CHEMISTRY; QUARTZ; PHASE AB Reactive chemical transport occurs in a variety of geochemical environments, and over a broad range of space and time scales. Efficiency of the chemical speciation and water-rock-gas interaction calculations is important for modeling field-scale multidimensional reactive transport problems. An improved efficient model, REACT, for simulating water-rock-gas interaction under equilibrium and kinetic conditions, has been developed. In this model, equilibrium and kinetic reactions are solved simultaneously by Newton-Raphson iteration. The REACT speciation model was coupled with the multidimensional nonisothermal multiphase flow and mass transport code TOUGH2, resulting in the general purpose reactive chemical transport simulator TOUGHREACT. An application to supergene copper enrichment of a typical copper protore that includes the sulfide minerals pyrite (FeS2) and chalcopyrite (CuFeS2) is presented. The efficiency and convergence of the present model is demonstrated from this numerically difficult application that involves very large variations in the concentrations of oxygen, and sulfide and sulfate species. TOUCHREACT provides a detailed description of water-rock-gas interactions during fully transient, multiphase, nonisothermal flow and transport in hydrologically and geochemically heterogeneous media. The code is helpful for assessment of acid mine drainage remediation, geothermal convection, waste disposal, contaminant transport and water quality. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Earth Sci, Mail Stop 90-1116,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM tianfu_xu@lbl.gov NR 28 TC 18 Z9 19 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-3004 EI 1873-7803 J9 COMPUT GEOSCI-UK JI Comput. Geosci. PD JUL PY 1999 VL 25 IS 6 BP 655 EP 666 DI 10.1016/S0098-3004(99)00005-9 PG 12 WC Computer Science, Interdisciplinary Applications; Geosciences, Multidisciplinary SC Computer Science; Geology GA 221BW UT WOS:000081705100004 ER PT J AU Creutz, M AF Creutz, M TI Computers and the particle theorist SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Creutz, M (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD JUL-AUG PY 1999 VL 1 IS 4 BP 14 EP 15 PG 2 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 211DZ UT WOS:000081145800005 ER PT J AU Hargrove, WW Hoffman, FM AF Hargrove, WW Hoffman, FM TI Using multivariate clustering to characterize ecoregion borders SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Univ Tennessee, Energy Environm & Resources Ctr, Syst Dev Inst, Res Fac, Knoxville, TN 37932 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Hargrove, WW (reprint author), Univ Tennessee, Energy Environm & Resources Ctr, Syst Dev Inst, Res Fac, 10521 Res Dr,Ste 100, Knoxville, TN 37932 USA. RI Hoffman, Forrest/B-8667-2012 OI Hoffman, Forrest/0000-0001-5802-4134 NR 14 TC 47 Z9 53 U1 1 U2 8 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD JUL-AUG PY 1999 VL 1 IS 4 BP 18 EP 25 DI 10.1109/5992.774837 PG 8 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 211DZ UT WOS:000081145800007 ER PT J AU Kaper, HG Wiebel, E Tipei, S AF Kaper, HG Wiebel, E Tipei, S TI Data sonification and sound visualization SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Educ Programs, Student Res Participat Program, Argonne, IL 60439 USA. Univ Illinois, Expt Music Studios, Urbana, IL 61801 USA. RP Kaper, HG (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 14 TC 16 Z9 17 U1 3 U2 4 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD JUL-AUG PY 1999 VL 1 IS 4 BP 48 EP 58 DI 10.1109/5992.774840 PG 11 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 211DZ UT WOS:000081145800010 ER PT J AU Haney, S Crotinger, J AF Haney, S Crotinger, J TI How templates enable high-performance scientific computing in C++ SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Pooma Project, Los Alamos, NM 87545 USA. RP Haney, S (reprint author), Univ Calif Los Alamos Natl Lab, Pooma Project, POB 1663, Los Alamos, NM 87545 USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD JUL-AUG PY 1999 VL 1 IS 4 BP 66 EP 72 DI 10.1109/5992.774843 PG 7 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 211DZ UT WOS:000081145800013 ER PT J AU Deplano, P Ferraro, JR Mercuri, ML Trogu, EF AF Deplano, P Ferraro, JR Mercuri, ML Trogu, EF TI Structural and Raman spectroscopic studies as complementary tools in elucidating the nature of the bonding in polyiodides and in donor-I-2 adducts SO COORDINATION CHEMISTRY REVIEWS LA English DT Review DE polyiodides; donor-I-2; adducts; Raman spectroscopy; X-ray diffraction ID RAY CRYSTAL-STRUCTURES; POLYHALIDE ANIONS; MOLECULAR-COMPLEXES; TRIIODIDE IONS; FT-RAMAN; DIIODINE; IODINE; SALTS; HEPTAIODIDE; METAL AB A large number of examples of polyiodides and donor-I-2, adducts whose structures and Raman spectra are reasonably well-established, have been collected. An empirical method based on structural and Raman data, as complementary tools in elucidating the nature of the iodine moiety, is proposed to remove the arbitrariness in considering discrete/non discrete entities and to provide a unified picture of the bonding in these species. Accordingly polyiodides higher than I-3(-) do not exist as discrete entities but are formed by a combination of I- and/or I-3(-) with I-2 through donor-acceptor interactions. The I-3(-) moiety represents a crossover, its structural and vibrational features show that it can exist as an I-3(-) entity tin accordance with the existence of a covalent bond interaction describable by means of a delocalized three-center four-electron, 3c-4e, bond or I- .I-2 donor-acceptor adduct. The formal I-2-adducts of donors (D) show structural and Raman features which can be explained considering three types of adducts: D.I-2 D-I-I (covalent bond interaction describable by means of a delocalized 3c-4e bond by analogy with the I-3(-) entity case) and (D-I)(+). I-, which can be considered as stages along the reaction coordinate between the separated D and I-2 and the salt [(D-I)(+)]I-. The precautions to be taken in studying these species have been cited. The possibility that some of the Raman attributes in the literature need corrections has been pointed out in regard to the instability inherent in these materials since the decomposition of these species causes spurious peaks to appear in the Raman spectrum. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Cagliari, Dipartimento Chim & Tecnol Inorgan & Met Orga, I-09124 Cagliari, Italy. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Deplano, P (reprint author), Univ Cagliari, Dipartimento Chim & Tecnol Inorgan & Met Orga, Via Osped 72, I-09124 Cagliari, Italy. NR 68 TC 140 Z9 143 U1 0 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0010-8545 J9 COORDIN CHEM REV JI Coord. Chem. Rev. PD JUL PY 1999 VL 188 BP 71 EP 95 DI 10.1016/S0010-8545(98)00238-0 PG 25 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 215KP UT WOS:000081381100004 ER PT J AU Ziomek-Moroz, M Su, W Covino, BS AF Ziomek-Moroz, M Su, W Covino, BS TI Investigation of passive films on alpha(2) and gamma titanium aluminides by X-ray photoelectron spectroscopy SO CORROSION LA English DT Article DE aluminum; films; intermetallics; potentiodynamic; potentiostatic; sodium hydroxide; sulfuric acid; titanium; titanium aluminide; x-ray photoelectron spectroscopy ID SURFACE CHARACTERIZATION; OXIDE-FILMS; STATE; ALLOYS; FE AB Passive films on alpha(2) and gamma titanium aluminide formed potentiostatically in sodium hydroxide (NaOH) and sulfuric acid (H2SO4) solutions were studied by x-ray photoelectron spectroscopy (XPS), In NaOH, potentiostatic experiments showed that titanium aluminides had very similar passive current densities to that of Ti. XPS sputter depth profile showed nearly no Al present in the outer layer of the passive films. In H2SO4, passive current densities increased for specimens with increasing Al content. XPS sputter depth profile showed that Al was enriched in. outer layers of the passive films. These results indicated that the passive film dissolution rate increased with increasing amounts of Al in the passive film for titanium aluminides. C1 Oregon Grad Inst, Dept Mat Sci & Engn, Portland, OR 97291 USA. Engn Animat Inc, Ames, IA 50010 USA. Albany Res Ctr, Dept Energy, Albany, OR 97321 USA. RP Ziomek-Moroz, M (reprint author), Oregon Grad Inst, Dept Mat Sci & Engn, POB 91000, Portland, OR 97291 USA. NR 17 TC 6 Z9 6 U1 1 U2 1 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0010-9312 J9 CORROSION JI Corrosion PD JUL PY 1999 VL 55 IS 7 BP 635 EP 643 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 215TF UT WOS:000081398500001 ER PT J AU Land, TA De Yoreo, JJ Martin, TL Palmore, GT AF Land, TA De Yoreo, JJ Martin, TL Palmore, GT TI A comparison of growth Hillock structure and step dynamics on KDP {100} and {101} surfaces using force microscopy SO CRYSTALLOGRAPHY REPORTS LA English DT Article ID DISLOCATION CORES; VICINAL HILLOCKS; CRYSTAL-GROWTH; FACE; MORPHOLOGY; KINETICS; KH2PO4; FLOW AB We report the results of in situ and ex situ atomic force microscopy investigations of hillock structure and step dynamics on the {100} face of KDP, as well as the effects of Fe3+ ions on the generation and motion of both elementary and macrosteps. We compare these results to those obtained previously on the {101} face. We show that, in contrast to the {101} face, dislocation sources on the {100} face do not exhibit dislocation cores, even for large Burgers vectors. Thus, for simple dislocation sources, the measured hillock slope depends on the Burgers vector and varies linearly with supersaturation. We show that while growth hillocks on the {101} faces are characterized by elementary steps that exhibit step homogenization, even in highly purified growth solutions, KDP {100} faces exhibit a tendency towards step bunching. We trace the evolution of this bunching with distance from the dislocation source and compare it to theoretical models of impurity-induced bunching. We also trace the evolution of step dynamics with supersaturation on the {100} face. We show that well above the dead zone, elementary steps and macrosteps are straight and elementary steps move more rapidly than macrosteps. As the supersaturation is decreased, impurity pinning begins to slow elementary step motion and the macrosteps begin to move faster than the elementary steps. In the region just above the dead zone, elementary steps are highly ramified and do not move while macrosteps continue to advance, sweeping up the elementary steps at the leading edge and leaving them behind at the trailing edge. Thus, in this region, growth occurs exclusively by the propagation of macrosteps. Finally, within the dead zone, both elementary and macrosteps cease to advance. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. RP Land, TA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. NR 38 TC 24 Z9 25 U1 1 U2 7 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7745 J9 CRYSTALLOGR REP+ JI Crystallogr. Rep. PD JUL-AUG PY 1999 VL 44 IS 4 BP 655 EP 666 PG 12 WC Crystallography SC Crystallography GA 224PF UT WOS:000081906900021 ER PT J AU Mukouyama, YS Chiba, N Mucenski, ML Satake, M Miyajima, A Hara, T Watanabe, T AF Mukouyama, YS Chiba, N Mucenski, ML Satake, M Miyajima, A Hara, T Watanabe, T TI Hematopoietic cells in cultures of the murine embryonic aorta-gonad-mesonephros region are induced by c-Myb SO CURRENT BIOLOGY LA English DT Article ID DEFINITIVE HEMATOPOIESIS; ENDOTHELIAL-CELLS; LINEAGES; MOUSE AB Definitive hematopoiesis begins in the para-aortic, splanchnopleural (P-Sp) and aorta-gonad-mesonephros (AGM) regions of mouse embryos and then switches to the fetal liver [1-3]. Gene-targeted mice lacking the c-Myb transcription factor have severe hematopoietic defects in the fetal liver [4], The role of c-Myb, if any, in P-Sp/AGM hematopoiesis has not been examined, however, Recently, we reported that oncostatin M can effectively expand both hematopoietic and endothelial-like cells from in vitro cultures of the AGM region [5]. Using this cell culture system, we examined the involvement of c-Myb in definitive hematopoiesis in the P-Sp and AGM regions. When primary cultures from the P-Sp or AGM regions of wildtype mouse embryos were probed with an anti-c-Myb antibody, hematopoietic cells but not endothelial like cells showed positive staining. In contrast, in the P-Sp/AGM culture from c-myb(-/-) embryos, no hematopoietic cells were generated and endothelial like cells predominated, indicating that the impairment of hematopoiesis in the liver of c-myb(-/-) embryos is actually preceded by a defect in P-Sp/AGM hematopoiesis. Hematogenic precursor cells were, however, still present in an inert but competent form among the endothelial-like, adherent cell population of c-myb(-/-) P-Sp/AGM cultures. When infected with a retrovirus carrying c-myb cDNA, these cultures gave rise to a significant number of hematopoietic cells. The rescued cells, unlike wild-type hematopoietic cells, were negative for c-Kit (a marker of hematopoietic progenitors), but did express other hematopoietic cell surface markers such as Mac-1, Gr-1 (myeloid markers), CD19, B220, Thy-1.2 (lymphoid markers), and Ter119 (an erythroid marker). Thus, c-Myb plays a role in the generation of hematopoietic cells in the embryonic P-Sp and AGM regions. C1 Tohoku Univ, Inst Dev Aging & Canc, Aoba Ku, Sendai, Miyagi 9808575, Japan. Univ Tokyo, Inst Mol & Cellular Biosci, Bunkyo Ku, Tokyo 1130032, Japan. Oak Ridge Natl Lab, Div Biol, Oak Ridge, TN 37831 USA. RP Watanabe, T (reprint author), Tohoku Univ, Inst Dev Aging & Canc, Aoba Ku, Sendai, Miyagi 9808575, Japan. NR 15 TC 34 Z9 35 U1 0 U2 2 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0960-9822 J9 CURR BIOL JI Curr. Biol. PD JUL-AUG PY 1999 VL 9 IS 15 BP 833 EP 836 DI 10.1016/S0960-9822(99)80368-6 PG 4 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 223QB UT WOS:000081850800025 PM 10469571 ER PT J AU Zhang, RG Evans, G Rotella, F Westbrook, E Huberman, E Joachimiak, A Collart, FR AF Zhang, RG Evans, G Rotella, F Westbrook, E Huberman, E Joachimiak, A Collart, FR TI Differential signatures of bacterial and mammalian IMP dehydrogenase enzymes SO CURRENT MEDICINAL CHEMISTRY LA English DT Review ID INOSINE 5'-MONOPHOSPHATE DEHYDROGENASE; MYCOPHENOLIC-ACID; INOSINE-5'-MONOPHOSPHATE DEHYDROGENASE; MONOPHOSPHATE DEHYDROGENASE; TRITRICHOMONAS-FETUS; BINDING; IDENTIFICATION; PURIFICATION; INHIBITION; COMPLEX AB IMP dehydrogenase (IMPDH) is an essential enzyme of de novo guanine nucleotide synthesis. IMPDH inhibitors have clinical utility as antiviral, anticancer or immunosuppressive agents. The essential nature of this enzyme suggests its therapeutic applications may be extended to the development of antimicrobial agents. Bacterial IMPDH enzymes show bio- chemical and kinetic characteristics that are different than the mammalian IMPDH enzymes, suggesting IMPDH may be an attractive target for the development of antimicrobial agents. We suggest that the biochemical and kinetic differences between bacterial and mammalian enzymes are a consequence of the variance of specific, identifiable amino acid residues. Identification of these residues or combination of residues that impart this mammalian or bacterial enzyme signature is a prerequisite for the rational identification of agents that specifically target the bacterial enzyme. We used sequence alignments of IMPDH proteins to identify sequence signatures associated with bacterial or eukaryotic IMPDH enzymes. These selections were further refined to discern those likely to have a role in catalysis using information derived from the bacterial and mammalian IMPDH crystal structures and site-specific mutagenesis. Candidate bacterial sequence signatures identified by this process include regions involved in subunit interactions, the active site flap and the NAD binding region. Analysis of sequence alignments in these regions indicates a pattern of catalytic residues conserved in all enzymes and a secondary pattern of amino acid conservation associated with the major phylogenetic groups. Elucidation of the basis for this mammalian/bacterial IMPDH signature will provide insight into the catalytic mechanism of this enzyme and the foundation for the development of highly specific inhibitors. C1 Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Collart, FR (reprint author), Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RI Evans, Gwyndaf/R-5524-2016; OI Evans, Gwyndaf/0000-0002-6079-2201; Collart, Frank/0000-0001-6942-4483 NR 17 TC 26 Z9 26 U1 0 U2 1 PU BENTHAM SCIENCE PUBL BV PI HILVERSUM PA PO BOX 1673, 1200 BR HILVERSUM, NETHERLANDS SN 0929-8673 J9 CURR MED CHEM JI Curr. Med. Chem. PD JUL PY 1999 VL 6 IS 7 BP 537 EP 543 PG 7 WC Biochemistry & Molecular Biology; Chemistry, Medicinal; Pharmacology & Pharmacy SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy GA 215BB UT WOS:000081361100003 PM 10390599 ER PT J AU Barnes, MD Ng, KC McNamara, KP Kung, CY Ramsey, JM Hill, SC AF Barnes, MD Ng, KC McNamara, KP Kung, CY Ramsey, JM Hill, SC TI Fluorescence imaging of single molecules in polymer microspheres SO CYTOMETRY LA English DT Article DE single-molecule imaging; microparticles; polymer ID ROOM-TEMPERATURE; MICRODROPLET STREAMS; SPECTROSCOPY; MICROSTRUCTURES; IDENTIFICATION; MANIPULATION; SIMULATION; STATISTICS; DIFFUSION; PROTEIN AB We report on far-field fluorescence imaging of single molecules in spherical polymer microparticles produced from solution by using microdroplet techniques. The fluorescence photobleaching quantum yields of rhodamine 6G in a common water-soluble polymer (polyvinyl alcohol) are at least five times smaller, corresponding to proportionally larger average fluorescence signals, than those in ethanolic solvents. This allows for acquisition of multiple images from a single molecule on a time scale of several minutes. We also show that fluorescent images of single molecules in microspheres can be calculated from semiclassic electrodynamics, which may ultimately be useful in retrieving dynamical information from experimental images. Cytometry 36:169-175, 1999 (C) 1999 Wiley-Liss, Inc. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. USA, Res Lab, Adelphi, MD USA. RP Barnes, MD (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, MS 6142, Oak Ridge, TN 37831 USA. NR 35 TC 12 Z9 12 U1 0 U2 4 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0196-4763 J9 CYTOMETRY JI Cytometry PD JUL 1 PY 1999 VL 36 IS 3 BP 169 EP 175 DI 10.1002/(SICI)1097-0320(19990701)36:3<169::AID-CYTO4>3.0.CO;2-I PG 7 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 209AL UT WOS:000081024800004 PM 10404964 ER PT J AU Ambrose, WP Goodwin, PM Nolan, JP AF Ambrose, WP Goodwin, PM Nolan, JP TI Single-molecule detection with total internal reflection excitation: Comparing signal-to-background and total signals in different geometries SO CYTOMETRY LA English DT Article DE single-molecule detection; fluorescence imaging; total internal reflection; photobleaching; B-phycoerythrin; rhodamine 6G ID LASER-INDUCED FLUORESCENCE; FIELD OPTICAL-EXCITATION; AQUEOUS-SOLUTION; ROOM-TEMPERATURE; B-PHYCOERYTHRIN; MICROSCOPY; SPECTROSCOPY; DIFFUSION; DYNAMICS; CRYSTAL AB Excitation of fluorescence with total internal reflection (TIR) excitation yields very low background scattered light and good signal-to-background contrast. The background and its associated noise can be made low enough to detect single fluorescent molecules under ambient conditions. In this paper, different TIR geometries were compared for excitation and detection of single rhodamine 6G (R6G) molecules at air-silica interfaces and single B-phycoerythrin proteins at water-silica interfaces. Through-objective, objective-coverslip, and prism-based TIR geometries were investigated. The signal-to-background ratio (SBR) and the number of photons detected before photobleaching (N-b) were optimum in different geometries. The greatest image contrast was obtained when using prism-TIR (SBR = 11.5), but the largest number of detected signal photoelectrons was obtained by using through-objective TIR for R6G-air-silica ([N-b] = 10(4)). The results were discussed in terms of the TIR field enhancements and the modified dipole emission pattern near a dielectric interface. The SBR;and total detected photons are important parameters for designing photon-limited experiments. Cytometry 30:224-231, 1993 (C) 1999 Wiley-Liss, Inc. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Ambrose, WP (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 45 TC 51 Z9 52 U1 1 U2 11 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0196-4763 J9 CYTOMETRY JI Cytometry PD JUL 1 PY 1999 VL 36 IS 3 BP 224 EP 231 DI 10.1002/(SICI)1097-0320(19990701)36:3<224::AID-CYTO12>3.0.CO;2-J PG 8 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 209AL UT WOS:000081024800012 PM 10404972 ER PT J AU Sheline, RK Singh, B Sood, PC Chu, SY AF Sheline, RK Singh, B Sood, PC Chu, SY TI Systematic investigation of hexadecapole collectivity in even-even nuclei SO CZECHOSLOVAK JOURNAL OF PHYSICS LA English DT Review ID INELASTIC ELECTRON-SCATTERING; LOW-LYING STATES; INTERACTING BOSON MODEL; TRANSITION CHARGE-DENSITIES; POLARIZED-PROTON SCATTERING; GAMMA-RAY TRANSITIONS; VIBRATIONAL-STATES; ALPHA-SCATTERING; DEFORMED-NUCLEI; STRENGTH DISTRIBUTIONS AB Energies of the first 2(+), 3(-) and 4(+) states of even-even nuclei are plotted against proton and neutron number. Using this systematics, shell effects and the corresponding quadrupole and hexadecapole collectivity and deformation effects are compared and contrasted. Also, the corresponding B(E2), B(E3) and B(E4) values are plotted against neutron number and their very different systematics compared. Among the new results are the presence of hexadecapole collectivity at the 82 proton and neutron closed shells and the presence of the maximum values of B(E4) at neutron numbers 10, 90-92 and 140-146. Finally, the systematics of the hexadecapole (K = 4(+)) vibrations is compared with that of the quadrupole (K = 2(+)) gamma vibrations in the quadrupole deformed rare earth region. C1 Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Banaras Hindu Univ, Dept Phys, Varanasi 221005, Uttar Pradesh, India. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Sheline, RK (reprint author), Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. NR 103 TC 5 Z9 5 U1 2 U2 3 PU CZECHOSLOVAK JNL OF PHYSICS PI PRAGUE PA FYZIKALNI USTAV AV NA SLOVANCE 2, PRAGUE 180 40, CZECH REPUBLIC SN 0011-4626 J9 CZECH J PHYS JI Czech. J. Phys. PD JUL PY 1999 VL 49 IS 7 BP 1047 EP 1066 DI 10.1023/A:1022885825020 PG 20 WC Physics, Multidisciplinary SC Physics GA 224HJ UT WOS:000081891700004 ER PT J AU Hakovirta, M Tiainen, VM Pekko, P AF Hakovirta, M Tiainen, VM Pekko, P TI Techniques for filtering graphite macroparticles in the cathodic vacuum arc deposition of tetrahedral amorphous carbon films SO DIAMOND AND RELATED MATERIALS LA English DT Review DE cathodic vacuum arc; graphite macroparticles; filtering; tetrahedral amorphous carbon ID DISCHARGE METHOD; MAGNETIC-FIELDS; DIAMOND FILMS; PLASMA SOURCE; LOW-STRESS; TRANSPORT; COATINGS; BEAMS; IMPLANTATION; GENERATION AB Filtered cathodic vacuum are (FCVA) deposition has been found to be a reliable technique for the production of high quality tetrahedral amorphous carbon films (ta-C). These coatings can be used as protective coatings for different applications ranging from cutting tools to human hip joint prosthesis. The FCVA technique is widely used in different laboratories around the world with somewhat different technical implementations. A serious disadvantage in the FCVA technique is the graphite particles that are emitted from the solid graphite cathode during the are-discharge. A variety of different techniques exist to diminish their production and transport. However, some of the magnetic filtering designs that are used to reduce the macroparticle transport into the substrate do not work well with high melting point cathode materials such as graphite. Although the influence of graphite particles for the ta-C coating performance in some applications is controversial, many applications demand that the produced ta-C film is practically particle-free. This is especially important in corrosion resistance, electrical and optical applications. In this paper an introduction to different FCVA devices is presented. Different magnetic filtering designs together with control techniques for macroparticle generation have been reviewed and their advantages and disadvantages in the plasma transport and particle filtering efficiency have been discussed. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Mat Sci & Tech Div MST8, Los Alamos, NM 87545 USA. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. RP Hakovirta, M (reprint author), Univ Calif Los Alamos Natl Lab, Mat Sci & Tech Div MST8, Mail Stop K762, Los Alamos, NM 87545 USA. NR 67 TC 25 Z9 25 U1 2 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD JUL PY 1999 VL 8 IS 7 BP 1183 EP 1192 DI 10.1016/S0925-9635(99)00111-9 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 213JL UT WOS:000081268900002 ER PT J AU Hakovirta, M AF Hakovirta, M TI Hardmetal woodcutting tool tips coated with tetrahedral amorphous carbon SO DIAMOND AND RELATED MATERIALS LA English DT Article DE adhesion; hardmetal; tetrahedral amorphous carbon; woodcutting tools ID ARC-DISCHARGE METHOD; DIAMOND FILMS; ION-BEAM; COATINGS; ADHESION AB Woodcutting tools with hardmetal (WC-Co) tool tips were coated with a high-quality (80% sp(3) bonding fraction) tetrahedral amorphous carbon (ta-C) him. The coatings were produced by filtered cathodic vacuum-are (FCVA) deposition. The problem with poor adhesion between the ta-C film and cobalt was solved by using an intermediate chromium layer structure. The adhesion was tested with a conventional scratch tester. In the case of a 1.2 mu m thick ta-C film with intermediate layer structure the critical load value was 31.6 N; without the intermediate layer it was 16.2 N. The lifetime of the ta-C-coated woodcutting tool was tested under normal production conditions with a computer numerical control (CNC) woodcutting machine. The lifetime of the woodcutting tool tip improved by a factor of three in the case of a 2.1 mu m thick multilayer (ta-C/Cr) film coating and by a factor of 1.5 in the case of a 1.0 mu m thick ta-C film coating with an 0.5 mu m thick intermediate chromium layer. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. RP Hakovirta, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 14 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD JUL PY 1999 VL 8 IS 7 BP 1225 EP 1228 DI 10.1016/S0925-9635(99)00097-7 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 213JL UT WOS:000081268900007 ER PT J AU Gorodetsky, AE Zalavutdinov, RK Zakharov, AP Hsu, WL Spitsyn, BV Bouilov, LL Stoyan, VP AF Gorodetsky, AE Zalavutdinov, RK Zakharov, AP Hsu, WL Spitsyn, BV Bouilov, LL Stoyan, VP TI AlN films grown on diamond and silicon carbide SO DIAMOND AND RELATED MATERIALS LA English DT Article DE aluminum nitride; CVD; diamond; 6H-SiC; heteroepitaxy AB Structural changes in surface layers of CVD AlN films were studied by the reflection high-energy electron diffraction technique. Film thickness was varied from 0.2 to 20 mu m. Single crystals of diamond, silicon carbide and also bilayered structures of natural diamond/CVD diamond films were used as substrates. On the (111) surfaces of natural diamond, (111) CVD diamond films and (00.1) 6H-SiC at AlN thickness up to 1 mu m one can observe the epitaxial correspondence between the growing him and the substrate: (00.1) [11.0] AlN//(111) [110] C-alpha or (00.1) [10.0] AlN//(00.1) [10.0] 6H-SiC. At larger film thickness the epitaxial growth was replaced gradually by the formation of one of axial textures for which the planes (00.1), (10.3) or (11.4) of wurtzite-like aluminum nitride were parallel to the substrate. During the epitaxial growth the twinning structures with the twinning planes of types (10.1) and (11.1) were observed. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Russian Acad Sci, Inst Phys Chem, Moscow 117915, Russia. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Gorodetsky, AE (reprint author), Russian Acad Sci, Inst Phys Chem, Leninsky Prospekt 31, Moscow 117915, Russia. NR 8 TC 9 Z9 10 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD JUL PY 1999 VL 8 IS 7 BP 1267 EP 1271 DI 10.1016/S0925-9635(99)00120-X PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 213JL UT WOS:000081268900015 ER PT J AU De Chant, LJ Pease, PP Tchakerian, VP AF De Chant, LJ Pease, PP Tchakerian, VP TI Modelling alluvial fan morphology SO EARTH SURFACE PROCESSES AND LANDFORMS LA English DT Article DE alluvial fans; modelling; fan hydrology; fan sedimentology AB A mathematical model which estimates the scale-independent sediment surface profile of alluvial fans has been developed. This model utilizes a diffusive sediment transport model and an unsteady, radial flow, conservation relationship. These equations are approximately solved assuming a quasi-steady-state closure with appropriate modelling assumptions for two end member fan types: (1) fans where most of the fan surface is depositionally active (denoted here as 'homogeneous') and (2) fans characterized by channelling and sediment sorting processes. The fundamental result for these two fan types is a dimensionless sediment profile relationship which approximates most fan surfaces. The model suggests that the overall dimensionless morphology of alluvial fans is governed more by fundamental diffusion principles in sediment deposition than by individual environmental or basin characteristics. Additionally, this work potentially can be extended to model temporal variation in fan development. Preliminary comparison with alluvial fan profiles is reasonable, indicating that this model provides useful qualitative and quantitative information relating to alluvial fan process and morphology. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 E Carolina Univ, Dept Geog, Greenville, NC 27858 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Texas A&M Univ, Dept Geog, College Stn, TX 77843 USA. Texas A&M Univ, Dept Geol & Geophys, College Stn, TX 77843 USA. RP Pease, PP (reprint author), E Carolina Univ, Dept Geog, Greenville, NC 27858 USA. NR 28 TC 14 Z9 14 U1 1 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0197-9337 J9 EARTH SURF PROC LAND JI Earth Surf. Process. Landf. PD JUL PY 1999 VL 24 IS 7 BP 641 EP 652 PG 12 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 216KT UT WOS:000081441800005 ER PT J AU Josowicz, M Li, HS Domansky, K Baer, DR AF Josowicz, M Li, HS Domansky, K Baer, DR TI Effect of oxidation state of palladium in polyaniline layers on sensitivity to hydrogen SO ELECTROANALYSIS LA English DT Article; Proceedings Paper CT International Symposium on Electrochemical and Biosensors (Matrafured 98) CY OCT 14-17, 1998 CL MATRAFURED, HUNGARY DE work function; hydrogen; polyaniline; palladium clusters; sensing ID RAY PHOTOELECTRON-SPECTROSCOPY; ELECTRONIC-STRUCTURE; CONDUCTING POLYMERS; OPTICAL-PROPERTIES; KELVIN PROBE; FILMS; DERIVATIVES; EMERALDINE AB It is shown that the ratio of Pd-0/Pd2+ in polyaniline (PANI) has a major effect on the response of film to hydrogen. The palladium clusters were incorporated in PANI as the result of spontaneous reduction of PdSO4 by electroactive PANI in the leucoemeraldine or nigraline form, respectively. The two forms of PANI were prepared by terminating the electrochemical deposition at -0.1 V (PANI-(0.1V)) and by terminating it at +0.7 V (PANI(0.7 V)). A higher amount of Pd is incorporated in the in PANI when the reduction of Pd2+ is initiated from the leucoemeraldine form. The ratio of the amine/imine units correlates well with the changes of the Pd-0/Pd2+ ratio as shown by the XPS. The changes of the work function were measured by a Kelvin Probe. A substantial decrease of WF was observed when the PANI-(0.1V)-Pd composite film was exposed to hydrogen. On the other hand the WF of PANI(0.7V)-Pd film increases upon exposure to hydrogen. The change in the electron donor/electron acceptor behavior towards hydrogen is governed by the Pd-0/Pd2+ ratio in the PANI/Pd matrix. C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Josowicz, M (reprint author), Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. RI Baer, Donald/J-6191-2013 OI Baer, Donald/0000-0003-0875-5961 NR 35 TC 11 Z9 11 U1 0 U2 5 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA POSTFACH 101161, 69451 WEINHEIM, GERMANY SN 1040-0397 EI 1521-4109 J9 ELECTROANAL JI Electroanalysis PD JUL PY 1999 VL 11 IS 10-11 BP 774 EP 781 DI 10.1002/(SICI)1521-4109(199907)11:10/11<774::AID-ELAN774>3.0.CO;2-O PG 8 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 226MU UT WOS:000082024400017 ER PT J AU Kepler, KD Vaughey, JT Thackeray, MM AF Kepler, KD Vaughey, JT Thackeray, MM TI Li(x)Cu(6)Sn(5) (0 < x < 13): An intermetallic insertion electrode for rechargeable lithium batteries SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID ION-BATTERIES; ALLOY ANODES; BINARY; OXIDE AB It has been discovered that lithium can be inserted into the intermetallic compound Cu(6)Sn(5) in a two-phase reaction to yield the product Li(x)Cu(6)Sn(5) (x approximate to 13). This finding has important implications for designing new intermetallic insertion electrodes (anodes) for rechargeable lithium batteries. The theoretical capacity of LixCu(6)Sn(5) derived from the eta-phase, eta-Cu(6)Sn(5), with a NiAs-type structure is 358 mAh/g for x(max) = 13, which corresponds to a fully lithiated composition Li(2.17)CuSn(0.83); this capacity is close to the theoretical capacity of lithiated graphite LiC(6) (372 mAh/g). The reaction occurs at approximately 0.4 V vs. lithium metal. The best cycling efficiency is obtained when the end voltage is restricted to 200 mV above the potential of lithium metal. A mechanism is proposed for the insertion of lithium into eta-Cu(6)Sn(5). (C) 1999 The Electrochemical Society. S1099-0062(99)01-079-4. All rights reserved. C1 Argonne Natl Lab, Electrochem Technol Program, Div Chem Technol, Argonne, IL 60439 USA. RP Kepler, KD (reprint author), Argonne Natl Lab, Electrochem Technol Program, Div Chem Technol, Argonne, IL 60439 USA. EM thackeray@cmt.anl.gov NR 16 TC 343 Z9 355 U1 8 U2 88 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 1099-0062 J9 ELECTROCHEM SOLID ST JI Electrochem. Solid State Lett. PD JUL PY 1999 VL 2 IS 7 BP 307 EP 309 DI 10.1149/1.1390819 PG 3 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 195YA UT WOS:000080278700001 ER PT J AU Khaselev, O Turner, JA AF Khaselev, O Turner, JA TI Photoelectrolysis of HBr and HI using a monolithic combined photoelectrochemical photovoltaic device SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID TANDEM SOLAR-CELLS; HYDROGEN; IODINE AB The photoelectrolysis of HBr and HI using a p-GaInP2(Pt)/GaAs photoelectrochemical/photovoltaic device is demonstrated. The device is a photoelectrochemical cell, voltage-biased with an integrated photovoltaic device. This device splits these acids directly on illumination, using light as the only energy input. Additionally, for these compounds, the device can simultaneously produce electrical energy. The HBr and HI decomposition efficiency for this system, based on the short-circuit current and the chemical potential of each compound, is 8.1 and 2.6%, respectively. The total conversion efficiency, including the cogenerated electrical energy, is 11.2 and 9.65%, respectively. (C) 1999 The Electrochemical Society. S1099-0062(99)02-011-8. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Khaselev, O (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Schaff, William/B-5839-2009 NR 15 TC 16 Z9 16 U1 1 U2 12 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 1099-0062 J9 ELECTROCHEM SOLID ST JI Electrochem. Solid State Lett. PD JUL PY 1999 VL 2 IS 7 BP 310 EP 312 DI 10.1149/1.1390820 PG 3 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 195YA UT WOS:000080278700002 ER PT J AU Vine, EL Kazakevicius, E AF Vine, EL Kazakevicius, E TI Residential energy use in Lithuania: the prospects for energy efficiency SO ENERGY LA English DT Article AB The energy demand in Lithuania's residential sector is very high. While the potential for saving energy in this sector is large, significant barriers to energy efficiency remain. Removing or ameliorating these barriers will be difficult since these are systemic barriers that require societal change. This article analyzes the barriers and offers several recommendations for promoting energy efficiency in Lithuania. Also, a proposal for short- and medium-term strategies for implementing such policies is proposed. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Vine, EL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg 90-2000, Berkeley, CA 94720 USA. NR 21 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD JUL PY 1999 VL 24 IS 7 BP 591 EP 603 DI 10.1016/S0360-5442(99)00013-4 PG 13 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 218PL UT WOS:000081560900004 ER PT J AU Dayton, DC Jenkins, BM Turn, SQ Bakker, RR Williams, RB Belle-Oudry, D Hill, LM AF Dayton, DC Jenkins, BM Turn, SQ Bakker, RR Williams, RB Belle-Oudry, D Hill, LM TI Release of inorganic constituents from leached biomass during thermal conversion SO ENERGY & FUELS LA English DT Article ID POWER PRODUCTION; COMBUSTION; GASIFICATION; REQUIREMENTS; HARVEST; QUALITY; GRASS AB Leaching of inorganic materials has recently been shown to substantially improve the combustion properties of biomass fuels, especially straw but including other herbaceous and woody fuels. Leaching with water removes large fractions of alkali metals (typically >80% of potassium and sodium) and chlorine (>90%). Smaller fractions of sulfur and phosphorus are also removed. Alkali metals are heavily involved in ash fouling and slagging in combustion and thermal gasification systems. Chlorine is a facilitator of alkali volatilization, and contributes to corrosion and air pollution. The presence of these elements has reduced or eliminated the use of certain biomass fuels in many combustion applications, even where such use might provide significant environmental benefits. Leaching could mitigate the undesirable effects of biomass ash in thermal systems. Reported here for the first time are comparative studies of volatile inorganic species evolving from leached and unleached biomass fuels during thermal conversion. Leached and unleached samples of rice straw, wheat straw, switchgrass, commercial power plant wood fuel, and banagrass (Pennisetum purpureum) were tested in bench-scale combustion studies using an alumina-tube flow reactor housed in a variable temperature furnace and coupled to a molecular beam mass spectrometer (MBMS) system. Sugarcane bagasse, as the leached byproduct of sugar production, was also tested. The MBMS system was used to monitor the combustion products, including inorganic vapors, directly and in real time during each batch combustion event. Total relative amounts of HCl(g), SO2(g), NaCl(g), KCl(g), and other species were compared for leached and unleached samples. The MBMS results were consistent with the levels of alkali metals and chlorine in the samples as determined from the proximate, ultimate, and ash analyses of the samples. The more alkali and chlorine in a given sample, the more gas-phase HCl, KCl, and NaCl detected with the MBMS during combustion of that particular sample. The MBMS results clearly support earlier results, which indicated that leaching biomass effectively reduces or eliminates the release of alkali metal vapors during combustion. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Calif Davis, Dept Biol & Agr Engn, Davis, CA 95616 USA. Univ Hawaii Manoa, Hawaii Nat Energy Inst, Honolulu, HI 96822 USA. RP Dayton, DC (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 24 TC 137 Z9 147 U1 1 U2 34 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD JUL-AUG PY 1999 VL 13 IS 4 BP 860 EP 870 DI 10.1021/ef980256e PG 11 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 219NY UT WOS:000081614400011 ER PT J AU Oasmaa, A Czernik, S AF Oasmaa, A Czernik, S TI Fuel oil quality of biomass pyrolysis oils - State of the art for the end user SO ENERGY & FUELS LA English DT Article ID FLASH PYROLYSIS AB Biomass pyrolysis oils have potential to be used as a fuel oil substitute. Combustion tests have shown that the oils burn efficiently in standard or slightly modified boilers and engines with rates similar to those for commercial fuels. However, these tests also identified several challenges in bio-oils applications resulting from their properties. The oils have heating values of only 40-50% of that for hydrocarbon fuels. They have a high water content that is detrimental for ignition. Organic acids in the oils are corrosive to common construction materials. Solids (char) can block injectors or erode turbine blades. Over time, reactivity of some components in the oils leads to formation of larger molecules that results in high viscosity and in slower combustion. This paper discusses physical and chemical characteristics of bio-oils relevant to fuel applications as well as some low-cost methods for improvement of these properties. It also provides bio-oil specifications proposed by some industrial users and recommendations for storage and handling. C1 NREL, Golden, CO 80401 USA. VTT Energy, Espoo, Finland. RP Czernik, S (reprint author), NREL, 1617 Cole Blvd, Golden, CO 80401 USA. NR 47 TC 357 Z9 383 U1 7 U2 75 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD JUL-AUG PY 1999 VL 13 IS 4 BP 914 EP 921 DI 10.1021/ef980272b PG 8 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 219NY UT WOS:000081614400019 ER PT J AU Autrey, T Linehan, JC Kaune, L Powers, TR McMillan, EF Stearns, C Franz, JA AF Autrey, T Linehan, JC Kaune, L Powers, TR McMillan, EF Stearns, C Franz, JA TI "FeS"-assisted scission of strong bonds in phenoxydiphenylmethanes. Competition between hydrogen atom transfer and free radical rearrangement pathways SO ENERGY & FUELS LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; SOLVENT-INDUCED SCISSION; DISSOCIATION-ENERGIES; DIPHENYLMETHANE HYDROCRACKING; DONOR SOLVENTS; MECHANISMS; CLEAVAGE; ETHER; LIQUEFACTION; PHASE AB Model compound studies comparing rates of decomposition and product distributions from ortho- and para-phenoxydiphenylmethanes [(PhO)PhCH2Ph] suggest that hydrogen atom abstraction from the model compounds, to yield a benzylic radical intermediate, competes with hydrogen atom transfer to the aryl rings from the reduced "FeS" catalyst. A free-radical rearrangement pathway involving o-phenoxydiphenylmethane, facilitated by the presence of the "FeS" catalyst, generated in situ from ferric oxyhydroxysulfate (OHS) and sulfur, leads to apparent Ar-OAr bond scission at temperatures significantly lower than expected for homolytic scission pathways. Thermolysis of the ortho isomer proceeds predominately through a pathway involving an intramolecular addition of the benzylic radical to the 1-position of the appended diphenyl ether, Ar-1-5 participation, forming a spirodienyl radical intermediate. Scission of the C-O bond, followed by hydrogen atom abstraction, yields thermally labile o-(hydroxyphenyl)phenylmethane (oHPPM). Under the reaction conditions, at 390 degrees C, tautomerism of oHPPM to the keto isomer followed by homolysis of the weak C-C bond in the keto intermediate yields diphenylmethane and phenol. To unambiguously demonstrate the importance of the free-radical rearrangement pathway, products from the thermolysis of o-(4-methylphenoxy)diphenylmethane were quantitatively determined. Decomposition of this labeled diaryl ether at 390 degrees C in 9,10-dihydrophenanthrene containing OHS/sulfur yields 4-methyldiphenylmethane and phenol as the major products. Catalytic decomposition of the corresponding para isomer, p-(4-methylphenoxy)diphenylmethane, where the intramolecular free-radical rearrangement pathway is hindered, shows that the rate of decomposition is significantly slower than observed for the corresponding ortho isomer, and 4-methyldiphenyl ether and toluene are the major products. The selectivity observed for the product distribution in the catalytic thermolysis of the para isomer is consistent with a reversible hydrogen atom transfer pathway from the "FeS" catalyst. C1 Pacific NW Lab, Div Chem Sci, Richland, WA 99352 USA. RP Autrey, T (reprint author), Pacific NW Lab, Div Chem Sci, POB 999, Richland, WA 99352 USA. NR 43 TC 4 Z9 4 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD JUL-AUG PY 1999 VL 13 IS 4 BP 927 EP 933 DI 10.1021/ef990009q PG 7 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 219NY UT WOS:000081614400021 ER PT J AU Ensminger, JT McCold, LN Webb, JW AF Ensminger, JT McCold, LN Webb, JW TI Environmental impact assessment under the National Environmental Policy Act and the Protocol on Environmental Protection to the Antarctic Treaty SO ENVIRONMENTAL MANAGEMENT LA English DT Article DE environment; impact assessment; Antarctica; NEPA; Protocol; Antarctic Treaty AB Antarctica has been set aside by the international community for protection as a natural reserve and a place for scientific research. Through the Antarctic Treaty of 1961, the signing nations ag reed to cooperate in protecting the antarctic environment, in conducting scientific studies, and in abstaining from the exercise of territorial claims. The 1991 signing of the Protocol on Environmental Protection to the Antarctic Treaty (Protocol) by representatives of the 26 nations comprising the Antarctic Treaty Consultative Parties (Parties) significantly strengthened environmental protection measures for the continent. The Protocol required ratification by each of the governments individually prior to official implementation. The US government ratified the Protocol by passage of the Antarctic Science, Tourism, and Conservation Act of 1997. Japan completed the process by ratifying the Protocol on December 15, 1997. US government actions undertaken in Antarctica are subject to the requirements of both the Protocol and the US National Environmental Policy Act (NEPA). There are differences in the scope and intent of the Protocol and NEPA; however, both require environmental impact assessment (EIA) as part of the planning process for proposed actions that have the potential for environmental impacts. In this paper we describe the two instruments and highlight key similarities and differences with particular attention to EIA. Through this comparison of the EIA requirements of NEPA and the Protocol, we show how the requirements of each can be used in concert to provide enhanced environmental protection for the antarctic environment. NEPA applies only to actions of the US government; therefore, because NEPA includes certain desirable attributes that have been refined and clarified through numerous court cases, and because the Protocol is just entering implementation internationally some recommendations are made for strengthening the procedural requirements of the Protocol for activities undertaken by all Parties in Antarctica. The Protocol gives clear and strong guidance for protection of specific, Valued antarctic environmental resources including intrinsic wilderness and aesthetic values, and the value of Antarctica as an area for scientific research. That guidance requires a higher standard of environmental protection for Antarctica than is required in other parts of the world. This paper shows that taken together NEPA and the Protocol call for closer examination of proposed actions and a more rigorous consideration of environmental impacts than either would alone. Three areas are identified where the EIA provisions of the Protocol could be strengthened to improve its effectiveness. First, the thresholds defined by the Protocol need to be clarified. Specifically, the meanings of the terms "minor" and "transitory" are not clear in the context of the Protocol. The use of "or" in the phrase "minor or transitory" further confuses the meaning. Second, cumulative impact assessment is called for by the Protocol but is not defined. A clear definition could reduce the chance that cumulative impacts would be given inadequate consideration. Finally, the public has limited opportunities to comment on or influence the preparation of initial or comprehensive environmental evaluations. Experience has shown that public input to environmental documents has a considerable influence on agency decision making and the quality of EIA that agencies perform. C1 Oak Ridge Natl Lab, Div Energy, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Ensminger, JT (reprint author), Oak Ridge Natl Lab, Div Energy, POB 2008,Bldg 4500N, Oak Ridge, TN 37831 USA. NR 13 TC 6 Z9 7 U1 4 U2 15 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0364-152X J9 ENVIRON MANAGE JI Environ. Manage. PD JUL PY 1999 VL 24 IS 1 BP 13 EP 23 DI 10.1007/s002679900211 PG 11 WC Environmental Sciences SC Environmental Sciences & Ecology GA 203DL UT WOS:000080692300002 ER PT J AU Duff, MC Hunter, DB Triay, IR Bertsch, PM Reed, DT Sutton, SR Shea-Mccarthy, G Kitten, J Eng, P Chipera, SJ Vaniman, DT AF Duff, MC Hunter, DB Triay, IR Bertsch, PM Reed, DT Sutton, SR Shea-Mccarthy, G Kitten, J Eng, P Chipera, SJ Vaniman, DT TI Mineral associations and average oxidation states of sorbed Pu on tuff SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID RAY-ABSORPTION-SPECTROSCOPY; PLUTONIUM; SPECIATION; URANIUM; SEDIMENTS; ADSORPTION; USA; HYDROLYSIS; CHEMISTRY; REDUCTION AB Subsurface transport of groundwater contaminants is greatly influenced by chemical speciation, precipitation, and sorption processes. The transport of Pu potentially released from spent nuclear fuel disposal and storage sites will be dependent on its interaction with mineral surfaces and speciation in the subsurface. The sorption of dissolved Pu(V) on a natural zeolitic tuff that was equilibrated with synthetic groundwater was examined using synchrotron-based microanalytical techniques. The tuff contained trace quantities of smectites and iron and manganese oxides, which are present as fracture fill and pore space materials. Synchrotron-based micro-X-ray fluorescence (SXRF) showed that Pu is predominately associated with manganese oxides (rancieite) and smectites but not with iron oxides (hematite). In situ micro-X-ray absorption near-edge structure (XANES) spectroscopy measurements on two highly enriched regions (similar to 10 x 15 mu m(2)) of Pu indicated that the average oxidation state of sorbed Pu was (+V) in one region and (+VI) in the other. The observed heterogeneous speciation of the sorbed Pu demonstrates the complex nature of this process. Thermodynamic equilibrium calculations indicated that the solution was dominated by negatively charged Pu species (such as PuO2CO3-), suggesting that sorption to the negatively charged manganese oxide surfaces would be energetically prohibited. Subsequent speciation changes upon sorption to manganese oxide surfaces are discussed. C1 Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Aiken, SC 29802 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Univ Chicago, Ctr Adv Radiat Sources, Chicago, IL 60637 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Duff, MC (reprint author), Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Drawer E, Aiken, SC 29802 USA. NR 46 TC 79 Z9 79 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 JUL 1 PY 1999 VL 33 IS 13 BP 2163 EP 2169 DI 10.1021/es9810686 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 213RD UT WOS:000081286300028 ER PT J AU Gu, B Phelps, TJ Liang, L Dickey, MJ Roh, Y Kinsall, BL Palumbo, AV Jacobs, GK AF Gu, B Phelps, TJ Liang, L Dickey, MJ Roh, Y Kinsall, BL Palumbo, AV Jacobs, GK TI Biogeochemical dynamics in zero-valent iron columns: Implications for permeable reactive barriers SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID SUBSURFACE REMEDIATION; CARBON-TETRACHLORIDE; ANAEROBIC CORROSION; CHROMATE REDUCTION; STRESS-CORROSION; FILM FORMATION; AQUEOUS-MEDIA; SULFATE; GROUNDWATER; HYDROGEN AB The impact of microbiological and geochemical processes has been a major concern for the long-term performance of permeable reactive barriers containing zero-valent iron (Fe-o). To evaluate potential biogeochemical impacts, laboratory studies were performed over a 5-month period using columns containing a diverse microbial community. The conditions chosen for these experiments were designed to simulate high concentrations of bicarbonate (17-33 mM HCO3-) and sulfate (7-20 mM SO42-) containing groundwater regimes. Groundwater chemistry was found to significantly affect corrosion rates of Fe-o filings and resulted in the formation of a suite of mineral precipitates. HCO3- ions in SO42-containing water were particularly corrosive to Fe-o, resulting in the formation of ferrous carbonate and enhanced H-2 gas generation that stimulated the growth of microbial populations and increased SO42- reduction. Major mineral precipitates identified included lepidocrocite; akaganeite, mackinawite, magnetite/maghemite, goethite, siderite, and amorphous ferrous sulfide. Sulfide was formed as a result of microbial reduction of SO42- that became significant after about 2 months of column operations; This study demonstrates that biogeochemical influences on the performance and reaction of Fe-o may be minimal in the short term (e.g., a few weeks or months), necessitating longer-term operations to observe the effects of biogeochemical reactions on the performance of Fe-o barriers. Although major failures of in-ground treatment barriers have not been problematic to date, the accumulation of iron oxyhydroxides, carbonates, and sulfides from biogeochemical processes could reduce the reactivity and permeability of Fe-o beds, thereby decreasing treatment efficiency. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. RP Gu, B (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Palumbo, Anthony/A-4764-2011; phelps, tommy/A-5244-2011; Gu, Baohua/B-9511-2012; Liang, Liyuan/O-7213-2014 OI Palumbo, Anthony/0000-0002-1102-3975; Gu, Baohua/0000-0002-7299-2956; Liang, Liyuan/0000-0003-1338-0324 NR 53 TC 185 Z9 192 U1 5 U2 48 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 JUL 1 PY 1999 VL 33 IS 13 BP 2170 EP 2177 DI 10.1021/es981077e PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 213RD UT WOS:000081286300029 ER PT J AU Aeschliman, DB Norton, GA AF Aeschliman, DB Norton, GA TI Collection and thermal evolution behaviors of different mercury species captured with gold SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ATMOSPHERIC MERCURY; AIR AB The effects of temperature on the collection and evolution of different mercury (Hg) species captured with gold were investigated to help determine if temperature control could be used to provide Hg speciation information in gaseous effluents. Elemental mercury, dimethyl mercury, and mercuric chloride were loaded onto a gold trap (one Hg species per test) at temperatures of 25-375 degrees C. The Hg was then evolved (in argon) at 900 degrees C. in other tests, Hg was loaded onto the trap at 25 degrees C and then heated (in argon) at 50-1000 degrees C to release Hg. The argon streams were analyzed using cold vapor atomic fluorescence to obtain information on Hg collection and evolution as a function of temperature. The Hg was released from the gold entirely as elemental mercury, regardless of the Hg species collected. Temperatures of about 250 degrees C were required to release the Hg, and there were no differences among Hg species with respect to the temperatures necessary to evolve the Hg. Results of the tests on Hg collection efficiency versus the temperature of the gold trap indicated that proper selection of the collection temperature could potentially be used to provide Hg speciation information-However refinements in the technique are necessary before it can be put into practical use. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Norton, GA (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 17 TC 6 Z9 13 U1 1 U2 4 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 JUL 1 PY 1999 VL 33 IS 13 BP 2278 EP 2283 DI 10.1021/es981030t PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 213RD UT WOS:000081286300044 ER PT J AU Schultz, IR Hayton, WL AF Schultz, IR Hayton, WL TI Interspecies scaling of the bioaccumulation of lipophilic xenobiotics in fish: An example using trifluralin SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE interspecies; scaling; bioconcentration; biotransformation; trifluralin ID TROUT ONCORHYNCHUS-MYKISS; 3 WATERBORNE CHLOROETHANES; IN-VITRO DATA; RAINBOW-TROUT; ORGANIC-CHEMICALS; TOXICOKINETIC MODEL; SALMO-GAIRDNERI; BODY-SIZE; DISPOSITION; METABOLISM AB A poorly understood factor that may influence differences in the accumulation of a xenobiotic among fishes is interspecies differences in physiology. We have extensively studied the uptake, distribution, and excretion kinetics of the lipophilic herbicide trifluralin (TF) in Ash. using a static water exposure system and compartmental toxicokinetic models. We obtained quantitative estimates of physiologically based toxicokinetic parameters such as uptake clearance, apparent volume of distribution, and elimination clearance due to xenobiotic metabolism, in rainbow trout, channel catfish, and bluegill sunfish at two acclimation temperatures. In these and other species (largemouth bass, gizzard shad, fathead minnows, and lake sturgeon), oxygen consumption rate, total lipid content, plasma protein binding, and in vitro biotransformation rates from liver homogenates were determined and examined for their capacities to predict toxicokinetic parameter values. The uptake clearance of TF was predictable based on the oxygen consumption rate, and in vitro TF biotransformation rate was a useful predictor of the in vivo metabolic clearance of TF. Lipid content, however, did not predict the apparent volume of distribution of TF. Values of uptake and metabolism clearance were predicted in largemouth bass, gizzard shad, fathead minnows, and lake sturgeon, using the oxygen consumption and the in vitro TF biotransformation rates. These predicted parameters were then used to successfully simulate the toxicokinetics of TF in these species. C1 Pacific NW Lab, Mol Biosci Dept, Richland, WA 99352 USA. Ohio State Univ, Coll Pharm, Columbus, OH 43210 USA. RP Schultz, IR (reprint author), Pacific NW Lab, Mol Biosci Dept, POB 999-P7-56, Richland, WA 99352 USA. NR 42 TC 17 Z9 19 U1 5 U2 16 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUL PY 1999 VL 18 IS 7 BP 1440 EP 1449 DI 10.1897/1551-5028(1999)018<1440:ISOTBO>2.3.CO;2 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 208ZB UT WOS:000081021400014 ER PT J AU Urban, W Kurcewicz, W Nowak, A Rzaca-Urban, T Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Bentaleb, M Lubkiewicz, E Schulz, N Blomqvist, J Daly, PJ Bhattacharyya, P Zhang, CT Ahmad, I Morss, LR AF Urban, W Kurcewicz, W Nowak, A Rzaca-Urban, T Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Bentaleb, M Lubkiewicz, E Schulz, N Blomqvist, J Daly, PJ Bhattacharyya, P Zhang, CT Ahmad, I Morss, LR TI Neutron single-particle energies in the Sn-132 region SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID STATES; FISSION; NUCLEI AB Excited levels in Sn-133 and Sb-134, populated in spontaneous fission of Cm-248, were studied by means of prompt-gamma spectroscopy, using the EWROGAM 2 multidetector array. The neutron i(13/2) single-particle energy has been determined for the first time in the Sn-132 region. The energy of the h(9/2) neutron level, proposed previously, has been confirmed. C1 Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Manchester, Dept Phys & Astron, Schuster Lab, Manchester M13 9PL, Lancs, England. IN2P3, CNRS, UMR7500, Inst Rech Subatom, F-67037 Strasbourg, France. Royal Inst Technol, Dept Phys Frescati, S-10405 Stockholm, Sweden. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Urban, W (reprint author), Univ Warsaw, Inst Expt Phys, Ul Hoza 69, PL-00681 Warsaw, Poland. NR 6 TC 57 Z9 57 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD JUL PY 1999 VL 5 IS 3 BP 239 EP 241 DI 10.1007/s100500050280 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 219PM UT WOS:000081615700001 ER PT J AU Carretta, P Tedoldi, F Rigamonti, A Galli, F Borsa, F Cho, JH Johnston, DC AF Carretta, P Tedoldi, F Rigamonti, A Galli, F Borsa, F Cho, JH Johnston, DC TI Spin dynamics in hole-doped two-dimensional S=1/2 Heisenberg antiferromagnets: Cu-63 NQR relaxation in La2-xSrxCuO4 for x <= 0.04 SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; LA-139 NQR; MU-SR; LA2CUO4; FLUCTUATIONS; LENGTH AB The effects on the correlated Cu2+ S = 1/2 spin dynamics in the paramagnetic phase of La2-xSrxCuO4 (for x less than or similar to 0.04) due to the injection of holes are studied by means of Cu-63 NQR spin-lattice relaxation time T-1 measurements. The results are discussed in the framework of the connection between T-1 and the in-plane magnetic correlation length xi(2D)(x, T). It is found that at high temperatures the system remains in the renormalized classical regime, with a spin stiffness constant rho(s)(x) reduced by small doping to an extent larger than the one due to Zn doping. For x greater than or similar to 0.02 the effect of doping on rho(s)(x) appears to level off. The values for rho(s)(x) derived from T-1 for T greater than or similar to 500 K are much larger than the ones estimated from the temperature behavior of sublattice magnetization in the ordered phase (T less than or equal to T-N). It is argued that these features are consistent with the hypothesis: of formation of stripes of microsegregated holes. C1 Ist Nazl Fis Nucl, Unita Pavia, Dept Phys A Volta, I-27100 Pavia, Italy. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Carretta, P (reprint author), Ist Nazl Fis Nucl, Unita Pavia, Dept Phys A Volta, Via Bassi 6, I-27100 Pavia, Italy. EM carretta@pv.infn.it NR 25 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6028 EI 1434-6036 J9 EUR PHYS J B JI Eur. Phys. J. B PD JUL PY 1999 VL 10 IS 2 BP 233 EP 236 DI 10.1007/s100510050850 PG 4 WC Physics, Condensed Matter SC Physics GA 228UG UT WOS:000082153600006 ER PT J AU Kharzeev, D Satz, H Syamtomov, A Zinovjev, G AF Kharzeev, D Satz, H Syamtomov, A Zinovjev, G TI J/psi-photoproduction and the gluon structure of the nucleon SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID ELECTROPRODUCTION; MESONS; HERA; QCD AB Using short distance QCD methods based on the operator product expansion, we calculate the J/psi photoproduction cross section in terms of the gluon distribution function of the nucleon. Comparing the result with data, we show that experimental behaviour of the cross section correctly reflects the x-dependence of the gluon distribution obtained from deep inelastic scattering. C1 Brookhaven Natl Lab, Riken BNL Inst, Upton, NY 11973 USA. Univ Bielefeld, Fak Phys, D-33501 Bielefeld, Germany. Natl Acad Sci Ukraine, Bogolyubov Inst Theoret Phys, UA-252143 Kiev, Ukraine. RP Kharzeev, D (reprint author), Brookhaven Natl Lab, Riken BNL Inst, Upton, NY 11973 USA. NR 20 TC 9 Z9 9 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD JUL PY 1999 VL 9 IS 3 BP 459 EP 462 DI 10.1007/s100520050039 PG 4 WC Physics, Particles & Fields SC Physics GA 224DJ UT WOS:000081881500010 ER PT J AU Casa, D Kiryukhin, V Saleh, OA Keimer, B Hill, JP Tomioka, Y Tokura, Y AF Casa, D Kiryukhin, V Saleh, OA Keimer, B Hill, JP Tomioka, Y Tokura, Y TI Persistent X-ray photoconductivity and percolation of metallic clusters in charge-ordered manganites SO EUROPHYSICS LETTERS LA English DT Article ID TRANSITION; STATES AB Charge-ordered manganites of composition Pr1 - x (Ca1 - ySry)(x)MnO3 exhibit persistent photoconductivity upon exposure to X-rays. This is not always accompanied by a significant increase in the number of conduction electrons as predicted by conventional models of persistent photoconductivity. An analysis of the X-ray diffraction patterns and current-voltage characteristics shows that X-ray illumination results in a microscopically phase-separated state in which charge-ordered insulating regions provide barriers against charge transport between metallic clusters. The dominant effect of X-ray illumination is to enhance the electron mobility by lowering or removing these barriers. A mechanism based on magnetic degrees of freedom is proposed. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Joint Res Ctr Atom Technol, Ibaraki, Osaka 305, Japan. Univ Tokyo, Dept Appl Phys, Tokyo 113, Japan. RP Casa, D (reprint author), Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RI Tokura, Yoshinori/C-7352-2009; Saleh, Omar/B-5014-2008; Casa, Diego/F-9060-2016 OI Saleh, Omar/0000-0002-9197-4024; NR 10 TC 16 Z9 16 U1 0 U2 2 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD JUL 1 PY 1999 VL 47 IS 1 BP 90 EP 96 DI 10.1209/epl/i1999-00356-y PG 7 WC Physics, Multidisciplinary SC Physics GA 218NZ UT WOS:000081559800015 ER PT J AU Zeman, J Jullian, S Martinez, G Yu, PY Uchida, K AF Zeman, J Jullian, S Martinez, G Yu, PY Uchida, K TI Nanometer size determination of type-II domains in CuPt-ordered GaInP2 with high-pressure magneto-luminescence SO EUROPHYSICS LETTERS LA English DT Article ID PHOTOLUMINESCENCE UP-CONVERSION; BAND ALIGNMENT; QUANTUM-DOT; ALLOYS AB Photoluminescence originating from the GaAs/(ordered)GaInP2 interface has been studied under the simultaneous application of high magnetic field and high pressure. A sharp threshold dependence on magnetic field was observed in the intensity of the spatially indirect. transition between electrons in GaInP2 and holes in GaAs. A model involving trapping of electrons from GaAs into "quantum boxes" formed by type-II ordered GaInP2 domains is proposed. This model reproduces the pressure-induced variations of the quantum box sizes and demonstrates the ability of this technique to study the properties of nanometer size systems. C1 Max Planck Inst Festkorperforsch, Grenoble High Magnet Field Lab, CNRS, F-38042 Grenoble 9, France. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Electrocommun, Dept Commun & Syst, Chofu, Tokyo 182, Japan. RP Zeman, J (reprint author), Max Planck Inst Festkorperforsch, Grenoble High Magnet Field Lab, CNRS, 22 Ave des Martyrs,BP 166, F-38042 Grenoble 9, France. NR 17 TC 2 Z9 2 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD JUL PY 1999 VL 47 IS 2 BP 260 EP 266 DI 10.1209/epl/i1999-00381-x PG 7 WC Physics, Multidisciplinary SC Physics GA 223KU UT WOS:000081840900020 ER PT J AU Wendt, K Blaum, K Bushaw, BA Gruning, C Horn, R Huber, G Kratz, JV Kunz, P Muller, P Nortershauser, W Nunnemann, M Passler, G Schmitt, A Trautmann, N Waldek, A AF Wendt, K Blaum, K Bushaw, BA Gruning, C Horn, R Huber, G Kratz, JV Kunz, P Muller, P Nortershauser, W Nunnemann, M Passler, G Schmitt, A Trautmann, N Waldek, A TI Recent developments in and applications of resonance ionization mass spectrometry SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article; Proceedings Paper CT 4th Symposium on Mass Spectrometric Methods for Element Trace Analysis CY SEP 28-OCT 01, 1998 CL JOHANNES GUTENBERG-UNIV NAINZ, MAINZ, GERMANY HO JOHANNES GUTENBERG-UNIV NAINZ ID TRACE ANALYSIS; ENVIRONMENTAL-SAMPLES; ACTINIDE ELEMENTS; SPECTROSCOPY; PLUTONIUM; CALCIUM; SR-90; SR-89 AB Resonance Ionization Mass Spectrometry (RIMS) has nowadays reached the status of a routine method for sensitive and selective ultratrace determination of long-lived radioactive isotopes in environmental, biomedical and technical samples. It provides high isobaric suppression, high to ultra-high isotopic selectivity and good overall efficiency. Experimental detection limits are as low as 10(6) atoms per sample and permit the fast and sensitive determination of ultratrace amounts of radiotoxic contaminations. Experimental arrangements for the detection of different radiotoxic isotopes, e.g. Pu236-244, Sr-89,Sr-90 and Tc-99 in environmental samples are described, and the application of RIMS to the ultrarare long-lived radioisotope Ca-41 for cosmochemical, radiodating and medical purposes are presented. C1 Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Univ Mainz, Inst Kernchem, D-55099 Mainz, Germany. Pacific NW Lab, Richland, WA 99352 USA. RP Wendt, K (reprint author), Univ Mainz, Inst Phys, D-55099 Mainz, Germany. RI Mueller, Peter/E-4408-2011; Wendt, Klaus/D-7306-2011; Nortershauser, Wilfried/A-6671-2013; OI Mueller, Peter/0000-0002-8544-8191; Wendt, Klaus/0000-0002-9033-9336; Nortershauser, Wilfried/0000-0001-7432-3687; Gruening, Carsten/0000-0002-6169-2827 NR 22 TC 45 Z9 45 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUL PY 1999 VL 364 IS 5 BP 471 EP 477 DI 10.1007/s002160051370 PG 7 WC Chemistry, Analytical SC Chemistry GA 219ZB UT WOS:000081637500020 ER PT J AU Richter, S Berglund, M Hennessy, C AF Richter, S Berglund, M Hennessy, C TI Magnesium isotope ratio measurements by negative thermal ionisation mass spectrometry using molecular fluoride ions SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article; Proceedings Paper CT 4th Symposium on Mass Spectrometric Methods for Element Trace Analysis CY SEP 28-OCT 01, 1998 CL JOHANNES GUTENBERG-UNIV NAINZ, MAINZ, GERMANY HO JOHANNES GUTENBERG-UNIV NAINZ AB A new technique for accurate Mg isotope ratio measurements has been developed with MgF2 as sample compound. With the help of a fluorinating agent negatively charged MgF3 molecular ions were formed in the ion source of a thermal ionisation mass spectrometer. An evaporation study has been performed and the results clearly show that Mg is evaporated from the filament as MgF2 molecules. The MgF2 technique has been applied in the certification of a candidate Mg-26-enriched Spike Isotope Reference Material. The result from this new technique has been compared with results obtained for the same material using ICP-MS. C1 Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. RP Richter, S (reprint author), New Brunswick Lab, 9800 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 11 Z9 11 U1 1 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUL PY 1999 VL 364 IS 5 BP 478 EP 481 DI 10.1007/s002160051371 PG 4 WC Chemistry, Analytical SC Chemistry GA 219ZB UT WOS:000081637500021 ER PT J AU Kaye, SM Ono, M Peng, YKM Batchelor, DB Carter, MD Choe, WH Goldston, R Hwang, YS Jaeger, EF Jarboe, TR Jardin, S Johnson, D Kaita, R Kessel, C Kugel, H Maingi, R Majeski, R Manickam, J Menard, J Mikkelsen, DR Orvis, DJ Nelson, BA Paoletti, F Pomphrey, N Rewoldt, G Sabbagh, S Strickler, DJ Synakowski, E AF Kaye, SM Ono, M Peng, YKM Batchelor, DB Carter, MD Choe, WH Goldston, R Hwang, YS Jaeger, EF Jarboe, TR Jardin, S Johnson, D Kaita, R Kessel, C Kugel, H Maingi, R Majeski, R Manickam, J Menard, J Mikkelsen, DR Orvis, DJ Nelson, BA Paoletti, F Pomphrey, N Rewoldt, G Sabbagh, S Strickler, DJ Synakowski, E TI Physics design of the National Spherical Torus Experiment SO FUSION TECHNOLOGY LA English DT Article ID LOW-Q DISRUPTIONS; HIGH-BETA; CONFINEMENT; TOKAMAKS; PLASMAS; DISCHARGES; STABILITY; ITER; PBX AB The mission of the National Spherical Torus Experiment (NSTX) is to prove the principles of spherical torus physics by producing high-beta(t) plasmas that are noninductively sustained and whose current profiles are in steady state. The NSTX will be one of the first ultralow-aspect-ratio tori (R/a less than or equal to 1.3) to operate at high power (P-input up to 11 MW) to produce high-beta(t) (25 to 40%), low-collisionality, high-bootstrap-fraction (less than or equal to 70%) dis charges. Both radio-frequency and neutral beam heating and current drive will be employed Built into the NSTX is sufficient configurational flexibility to study a range of operating space and the resulting dependences of the confinement, micro- and magnetohydrodynamic stability, and particle- and power-handing properties. NSTX research will be carried out by a nationally based science team. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. Korea Adv Inst Sci & Technol, Taejon, South Korea. Univ Washington, Seattle, WA 98105 USA. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. RP Kaye, SM (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Jardin, Stephen/E-9392-2010; pomphrey, neil/G-4405-2010; Sabbagh, Steven/C-7142-2011; Choe, Wonho/C-1556-2011; Hwang, Yong-Seok/D-8347-2012; OI Menard, Jonathan/0000-0003-1292-3286 NR 52 TC 81 Z9 82 U1 0 U2 5 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD JUL PY 1999 VL 36 IS 1 BP 16 EP 37 PG 22 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 209EF UT WOS:000081034700002 ER PT J AU Fontana, RJ Lown, KS Paine, MF Fortlage, L Santella, RM Felton, JS Knize, MG Greenberg, A Watkins, PB AF Fontana, RJ Lown, KS Paine, MF Fortlage, L Santella, RM Felton, JS Knize, MG Greenberg, A Watkins, PB TI Effects of a chargrilled meat diet on expression of CYP3A, CYP1A, and P-glycoprotein levels in healthy volunteers SO GASTROENTEROLOGY LA English DT Article ID HYDROCARBON-DNA ADDUCTS; HETEROCYCLIC AROMATIC-AMINES; WHITE BLOOD-CELLS; ERYTHROMYCIN BREATH TEST; SMALL-BOWEL ENTEROCYTES; CHARCOAL-BROILED BEEF; COLON-CANCER; CYTOCHROME P4501A2; MESSENGER-RNA; RAT-LIVER AB Background & Aims: Carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons present in chargrilled meat are substrates for inducible CYP1A and CYP3A enzymes and for P-glycoprotein. We examined whether consumption of a chargrilled meat diet results in induction of these proteins. Methods: Ten healthy adults were fed a diet enriched with chargrilled meat for 7 days. Duodenal biopsy specimens were obtained on days 1, 5, and 12 and analyzed for CYP1A, CYP3A, and P-glycoprotein messenger RNA (mRNA) and protein. On days 5 and 12, hepatic CYP3A4 and CYP1A2 activities were measured and colon biopsies were performed. The levels of polycyclic aromatic hydrocarbon DNA adducts in peripheral blood mononuclear cells were measured on days 1, 4, 11, and 26. Results: Them was no detectable induction of CYP3A4, CYP3A5, or P-glycoprotein mRNAs or protein in small intestine or colon and no induction of hepatic CYP3A4 enzyme activity. In contrast, the chargrilled meat diet resulted in unequivocal induction of CYP1A enzymes in the liver and small intestine of each subject. There was; an inverse correlation between the level of peripheral polycyclic aromatic hydrocarbon DNA adducts measured on day 11 and both liver CYP1A2 activity 1(P = 0.027) and enterocyte CYP1A1 protein concentration (P = 0.046). Conclusions: Ingestion of chargrilled meat results in induction of CYP1A enzymes but not CYP3A4 or P-glycoprotein. This observation, combined with the correlation between adduct levels and CYP1A expression, supports an adaptive role for CYP1A but not CYP3A4 or P-glycoprotein. C1 Univ Michigan, Med Ctr, Sch Med, Dept Internal Med, Ann Arbor, MI 48109 USA. Columbia Univ, Div Environm Hlth Sci, New York, NY USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA USA. Univ N Carolina, Dept Chem, Charlotte, NC 28223 USA. RP Watkins, PB (reprint author), Univ Michigan, Med Ctr, Sch Med, Dept Internal Med, 1500 E Med Ctr Dr,2150 CCGC 0903, Ann Arbor, MI 48109 USA. FU NCRR NIH HHS [MO1RR00042]; NIGMS NIH HHS [GM38149-11, GM53095-01] NR 69 TC 81 Z9 82 U1 1 U2 7 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 USA SN 0016-5085 J9 GASTROENTEROLOGY JI Gastroenterology PD JUL PY 1999 VL 117 IS 1 BP 89 EP 98 DI 10.1016/S0016-5085(99)70554-8 PG 10 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA 212GJ UT WOS:000081208700019 PM 10381914 ER PT J AU Phillips, DH FitzPatrick, EA AF Phillips, DH FitzPatrick, EA TI Biological influences on the morphology and micromorphology of selected Podzols (Spodosols) and Cambisols (Inceptisols) from the eastern United States and north-east Scotland SO GEODERMA LA English DT Article DE Podzols; Cambisols; micromorphology; macrofauna; mesofauna; faecal pellets ID SOIL STRUCTURE AB Biological activities greatly influence the formation of many soils, especially forest soils under cool humid climates. The objective of this study was to investigate the effects of vegetation and soil biota on the formation of selected soils. Field morphology, micromorphology, and carbon and organic matter analysis were determined on six Podzols (Spodosols) and two Cambisols (Inceptisols) from the eastern United States and north-east Scotland. Humification of plant material by soil fauna and fungi occurs in all organic horizons. Thick organic coatings are observed on soil peds and rock fragments from the El to the Bs horizon in a Haplic Podzol from Clingmans Dome Mt., TN. Thin sections reveal large accumulations of root material in different stages of decomposition in the spodic horizons of a Haplic Podzol from Whiteface Mt., NY. Organic carbon ranges from 5.4 to 8.5% in the spodic B horizons of the Whiteface Mt. Podzol. Earthworms and enchytraeids have a great effect on the structure of the surface and subsurface horizons in the Dystric Cambisols from Huntly and Clashindarroch Forests, Scotland and a Cambic Podzol from the Corrie Burn Basin, Scotland. Podzols from Speymouth Forest, Scotland (Gleyic Podzol), Clingmans Dome Mt., and Whiteface Mt. have thick organic horizons. The Podzols from the Flatwoods in Georgia, the Pine Barrens in New Jersey, the Corrie Burn Basin, and the Cambisol from Huntly Forest have only A horizons at the surface. The Clashindarroch Forest soil has a very thin organic horizon. Warm and humid climates and sandy parent material are responsible for thick E horizons and lack of thick organic horizons in the Flatwoods (Carbic Podzol) and Pine Barrens (Ferric Podzol) soils. Earthworms and enchytraeids thrive in the Corrie Burn Basin and Huntly Forest soils due to the vegetation and the highly weathered basic parent material. The site at Clashindarroch once carried oak, and then birch forest, both of which produce a mild litter and also encourage earthworm and enchytraeids. This fauna is responsible for much mixing of the topsoil. The present conifer vegetation will eventually produce a deep Litter and cause podzolization. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Aberdeen, Dept Plant & Soil Sci, Aberdeen, Scotland. RP Phillips, DH (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Phillips, Debra/F-1828-2010 OI Phillips, Debra/0000-0001-8548-7409 NR 44 TC 26 Z9 26 U1 7 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0016-7061 J9 GEODERMA JI Geoderma PD JUL PY 1999 VL 90 IS 3-4 BP 327 EP 364 DI 10.1016/S0016-7061(98)00121-9 PG 38 WC Soil Science SC Agriculture GA 217UX UT WOS:000081518200010 ER PT J AU Smith, JP Thomsen, MF Borovsky, JE Collier, M AF Smith, JP Thomsen, MF Borovsky, JE Collier, M TI Solar wind density as a driver for the ring current in mild storms SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA SHEET; POPULATION AB Using the methods of multi- and partial-linear-correlation, we demonstrate that both the solar wind density and the solar wind electric field make significant and independent contributions to the strength of the ring current, as measured by the Dst* index, during mild storms. The solar wind data were obtained from WIND, and the Dst data from OmniWeb. After appropriate cleaning of the data, 55 events from the Wind-era with Dst* excursions below -50 were obtained. Correlations with Dst* were performed with independent, variable time lags for the density and for the electric field,:and the optimal time lags are found to be approximately 5 hours for density and less than one hour for the electric field (in addition to the time shift to Earth). C1 Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, JP (reprint author), Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. NR 15 TC 22 Z9 22 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1999 VL 26 IS 13 BP 1797 EP 1800 DI 10.1029/1999GL900341 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000004 ER PT J AU Reisenfeld, DB McComas, DJ Steinberg, JT AF Reisenfeld, DB McComas, DJ Steinberg, JT TI Evidence of a solar origin for pressure balance structures in the high-latitude solar wind SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ULYSSES OBSERVATIONS; CORONAL PLUMES; HOLES; PLASMA AB Ulysses observations of the high-latitude solar wind have shown that on time scales of < 1 day, the polar wind is dominated by pressure balance structures (PBSs). Fluctuations of the plasma beta within PBSs appear to be strongly correlated with fluctuations in the helium abundance. The correlation occurs in both the northern and southern hemispheres. In addition, a mechanism is apparently at work in the high-latitude solar wind that dissipates the beta/He correlation over a distance of a few AU. Solar wind composition is established at the base of the corona; thus, the He abundance signature strongly suggests the observed solar wind PBSs are associated with structures low in the solar atmosphere. In particular, high-beta structures appear to originate in locations of enhanced He abundance. We suggest an interpretation of the high-beta portion of PBSs as the solar wind extensions of polar plumes. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reisenfeld, DB (reprint author), Univ Calif Los Alamos Natl Lab, M-S-D44, Los Alamos, NM 87545 USA. RI Reisenfeld, Daniel/F-7614-2015 NR 19 TC 30 Z9 30 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1999 VL 26 IS 13 BP 1805 EP 1808 DI 10.1029/1999GL900368 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000006 ER PT J AU Bish, D Chipera, S Guthrie, G AF Bish, D Chipera, S Guthrie, G TI Clays SO GEOTIMES LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Geol & Geochem Grp, Los Alamos, NM 87545 USA. RP Bish, D (reprint author), Univ Calif Los Alamos Natl Lab, Geol & Geochem Grp, POB 1663, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 USA SN 0016-8556 J9 GEOTIMES JI Geotimes PD JUL PY 1999 VL 44 IS 7 BP 34 EP 35 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 220AH UT WOS:000081641300034 ER PT J AU Cong, G Parvin, B AF Cong, G Parvin, B TI An algebraic solution to surface recovery from cross-sectional contours SO GRAPHICAL MODELS AND IMAGE PROCESSING LA English DT Article ID SHAPE RECONSTRUCTION; RADAR INTERFEROMETRY; PLANAR CONTOURS; TRIANGULATION; IMAGES AB A new approach for reconstruction of 3D surfaces from 2D cross-sectional contours is presented. By using the so-called "equal importance criterion," we reconstruct the surface based on the assumption that every point in the region contributes equally to the surface reconstruction process. In this context, the problem is formulated in terms of a partial differential equation, and we show that the solution for dense contours (contours in close proximity) can be efficiently derived from the distance transform. In the case of sparse contours, we add a regularization term to ensure smoothness in surface recovery. The approach is also generalized to other types of cross-sectional contours, where the spine may not be a straight line. The proposed technique allows for surface recovery at any desired resolution. The main advantages of our method is that inherent problems due to correspondence, tiling, and branching are avoided. In contrast to existing implicit methods, we find an optimal field function and develop an interpolation method that does not generate any artificial surfaces. Ne will demonstrate that the computed high-resolution surface is well represented for subsequent geometric analysis. We present results on both synthetic and real data. (C) 1999 Academic Press. C1 Lawrence Berkeley Lab, Informat & Comp Sci Div, Berkeley, CA 94720 USA. RP Cong, G (reprint author), Lawrence Berkeley Lab, Informat & Comp Sci Div, Berkeley, CA 94720 USA. NR 34 TC 14 Z9 23 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1077-3169 J9 GRAPH MODEL IM PROC JI Graph. Models Image Process. PD JUL PY 1999 VL 61 IS 4 BP 222 EP 243 DI 10.1006/gmip.1999.0499 PG 22 WC Computer Science, Software Engineering SC Computer Science GA 239TC UT WOS:000082784900003 ER EF