FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Torgersen, T Kennedy, BM AF Torgersen, T Kennedy, BM TI Air-Xe enrichments in Elk Hills oil field gases: role of water in migration and storage SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE hydrocarbons; noble gases; xenon ID NOBLE-GASES; GROUNDWATER-FLOW; RARE-GAS; BASIN; SOLUBILITY; ACCUMULATION; CONSTRAINTS; PETROLEUM; DEPOSITS; HELIUM AB Hydrocarbons from the Elk Hills Naval Petroleum Reserve (NPR#1), Bakersfield, CA, are enriched in heavy noble gases. The Xe-132/Ar-36 ratios are as high as similar to 576 times the ratio in air and represent the largest relative Xe-enrichments ever observed in terrestrial fluids. The Xe isotopic composition is indistinguishable from air. We show that these samples cannot be explained by equilibration of oil with air saturated water and secondary enrichment via a Rayleigh distillation gas stripping process. Based on laboratory studies of others with potential petroleum source rocks, we believe the source of this enriched heavy noble gas component was adsorbed air initially trapped in/on the source rocks that was expelled and mixed with the hydrocarbons during expulsion and primary migration. Kr and Xe enrichments decrease with increasing Ar-36 concentration. We propose a model in which an initial Kr-Xe-enriched hydrocarbon becomes diluted with noble gases extracted from air saturated groundwater during expulsion, migration, and storage. The model generates an integrated water/hydrocarbon ratio for the production fluid which indicates a minimal role for water in hydrocarbon expulsion and migration. The results are interpreted to provide time/geometrical constraints on the mechanisms by which hydrocarbons can migrate as a separate phase. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Connecticut, Dept Marine Sci, Groton, CT 06340 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Isotope Geochem, Berkeley, CA 94720 USA. RP Torgersen, T (reprint author), Univ Connecticut, Dept Marine Sci, Groton, CT 06340 USA. NR 29 TC 34 Z9 38 U1 2 U2 6 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 APR 15 PY 1999 VL 167 IS 3-4 BP 239 EP 253 DI 10.1016/S0012-821X(99)00021-7 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 183FE UT WOS:000079542900010 ER PT J AU Vanderberg, LA Foreman, TM Attrep, M Brainard, JR Sauer, NN AF Vanderberg, LA Foreman, TM Attrep, M Brainard, JR Sauer, NN TI Treatment of heterogeneous mixed wastes: Enzyme degradation of cellulosic materials contaminated with hazardous organics and toxic and radioactive metals SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CELLULASE ACTIVITIES; BIOREMEDIATION; MICROORGANISMS; BIODEGRADATION; BIOREACTOR; REMOVAL AB The redirection and downsizing of the U.S. Department of Energy's nuclear weapons complex requires that many facilities be decontaminated and decommissioned (D&D). At Los Alamos National Laboratory, much of the low-level radioactive, mixed, and hazardous/chemical waste volume handled by waste management operations was produced by D&D and environmental restoration activities. A combination of technologies-air stripping and biodegradation of volatile organics, enzymatic digestion of cellulosics, and metal ion extraction-was effective in treating a radiologically contaminated heterogeneous paint-stripping waste. Treatment of VOCs using a modified bioreactor avoided radioactive contamination of byproduct biomass and inhibition of biodegradation by toxic metal ions in the waste. Cellulase digestion of bulk cellulose minimized the final solid waste volume by 80%. Moreover, the residue passed TCLP for RCRA metals. Hazardous metals and radioactivity in byproduct sugar solutions were removed using polymer filtration, which employs a combination of water-soluble chelating polymers and ultrafiltration to separate and concentrate metal contaminants. Polymer filtration was used to concentrate RCRA metals and radioactivity into <5% of the original wastewater volume. Permeate solutions had no detectable radioactivity and were below RCRA-allowable discharge limits for Pb and Cr. C1 Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Vanderberg, LA (reprint author), Los Alamos Natl Lab, Chem Sci & Technol Div, Mailstop E-529, Los Alamos, NM 87545 USA. EM lvanderberg@lanl.gov NR 34 TC 5 Z9 5 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X EI 1520-5851 J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD APR 15 PY 1999 VL 33 IS 8 BP 1256 EP 1262 DI 10.1021/es9804262 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 190QC UT WOS:000079974600018 ER PT J AU Davis, WB Wasielewski, MR Ratner, MA AF Davis, WB Wasielewski, MR Ratner, MA TI Influence of substituents and chain length on the optical properties of poly(p-phenylenevinylene) oligomers SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article ID TRANSITION-METAL COMPLEXES; LIGHT-EMITTING-DIODES; ELECTRONIC-STRUCTURE; CONJUGATED POLYMERS; POLY(PARA-PHENYLENE VINYLENE); INTERMEDIATE NEGLECT; COPOLYMERS; HYPERPOLARIZABILITIES; SPECTROSCOPY; DERIVATIVES AB Electronic-structure calculations based upon the Pariser-Parr-Pople semiempirical Hamiltonian were applied to short-chain oligomers of the conducting polymer poly(p-phenylenevinylene) (PPV) to study the effects of appending methoxy groups along the backbone as well as push-pull nitro and amino groups at the ends of the oligomers. Optical absorption spectra were calculated utilizing configuration interaction methods at the single-excitation level, and the nonlinear optical properties of the push-pull oligomers were studied using the sum-over-states approach. In short-chain oligomers, the calculated electronic and optical properties are controlled by the nature of the pendant groups. However, in the longest oligomers studied, these molecular properties are relatively insensitive to any of the studied modifications. (C) 1999 John Wiley & Sons, Inc. C1 Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Wasielewski, MR (reprint author), Northwestern Univ, Dept Chem, 2145 N Sheridan Rd, Evanston, IL 60208 USA. NR 61 TC 18 Z9 18 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0020-7608 J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD APR 15 PY 1999 VL 72 IS 4 BP 463 EP 471 DI 10.1002/(SICI)1097-461X(1999)72:4<463::AID-QUA29>3.0.CO;2-H PG 9 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 176TG UT WOS:000079167400024 ER PT J AU Demos, SG Staggs, M Yan, M Radousky, HB De Yoreo, JJ AF Demos, SG Staggs, M Yan, M Radousky, HB De Yoreo, JJ TI Investigation of optically active defect clusters in KH2PO4 under laser photoexcitation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID POTASSIUM DIHYDROGEN PHOSPHATE; ELECTRONIC DEFECTS; RAMAN-SCATTERING; ALKALI-HALIDES; CRYSTALS; AGGREGATION; ABSORPTION; KI AB Photoexcited defect clusters in the bulk of KH2PO4 crystals are investigated using a microscopic fluorescence imaging system with 1 mu m spatial resolution. The observed defect cluster concentration is approximately 10(4)-10(6) per mm(3) depending on the crystal growth method and sector of the crystal. The intensity of the emission clusters varies widely within the image field while a nearly uniformly distributed background is present. Spectroscopic measurements provided information on the emission characteristics of the observed defect population. (C) 1999 American Institute of Physics. [S0021-8979(99)05008-2]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94580 USA. RP Demos, SG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94580 USA. NR 22 TC 18 Z9 19 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 APR 15 PY 1999 VL 85 IS 8 BP 3988 EP 3992 DI 10.1063/1.370301 PN 1 PG 5 WC Physics, Applied SC Physics GA 188LN UT WOS:000079848600008 ER PT J AU Aichmayr, G Toet, D Mulato, M Santos, PV Spangenberg, A Christiansen, S Albrecht, M Strunk, HP AF Aichmayr, G Toet, D Mulato, M Santos, PV Spangenberg, A Christiansen, S Albrecht, M Strunk, HP TI Dynamics of lateral grain growth during the laser interference crystallization of a-Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SILICON THIN-FILMS; AMORPHOUS-SILICON; SOLIDIFICATION; GERMANIUM AB Laser interference crystallization of amorphous silicon (a-Si) thin films, a technique that combines pulsed laser crystallization with holography, enables the fabrication of periodic arrays of polycrystalline silicon (poly-Si) lines with lateral dimensions between 0.5 and 20 mu m. The lines consist of grains with well-defined grain boundary locations and lateral dimensions that are appreciably larger than the thickness of the initial a-Si:H film (up to 2 mu m for a 300 nm thick film). We investigated the dynamics of the crystallization process by two-dimensional finite element computer simulations of the heat transport and phase transitions during laser crystallization. The theoretical results were compared to: (i) measurements of the crystallization kinetics, determined by recording the transient changes of the reflectance during laser exposure, and to (ii) the structural properties of the crystallized films, determined by scanning force and transmission electron microscopy. The simulations indicate that the crystallization front responsible for the large grains propagates laterally from the edges of the molten silicon lines to their centers with a velocity of similar to 14 m/s. A substantial lateral growth only occurs for laser intensities large enough to melt the a-Si film around the center of the lines down to the substrate. Vertical crystallization, which is substantially slower (0.5 m/s), also participates in the solidification process. Using a transfer matrix approach, we converted the time-dependent phase and temperature distributions generated by the simulation program into values for the reflection and transmission of the film as a function of time during and after the laser exposure. A good agreement between the simulated and measured transient reflection was obtained both in the case of homogeneous crystallization as well as that of laser interference crystallization. (C) 1999 American Institute of Physics. [S0021-8979(99)02808-X]. C1 Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Autonomous Univ Madrid, Dept Fis Mat, E-28049 Madrid, Spain. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. Paul Drude Inst Festkorperelekt, D-10117 Berlin, Germany. Univ Erlangen Nurnberg, Inst Werkstoffwissensch 7, D-91058 Erlangen, Germany. RP Santos, PV (reprint author), Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany. RI Mulato, Marcelo/J-7756-2012; Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 27 TC 35 Z9 35 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 APR 15 PY 1999 VL 85 IS 8 BP 4010 EP 4023 DI 10.1063/1.370305 PN 1 PG 14 WC Physics, Applied SC Physics GA 188LN UT WOS:000079848600012 ER PT J AU Shen, TD Schwarz, RB Thompson, JD AF Shen, TD Schwarz, RB Thompson, JD TI Paramagnetism, superparamagnetism, and spin-glass behavior in bulk amorphous Pd-Ni-Fe-P alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GIANT MAGNETORESISTANCE; MAGNETIC-PROPERTIES; REMANENT MAGNETIZATION; NANOCOMPOSITE SYSTEMS; FIELD-DEPENDENCE; METALLIC-GLASS; PARTICLES; MAGNETOTRANSPORT; SUSCEPTIBILITY; ANISOTROPY AB We have investigated the magnetic properties of bulk amorphous Pd40Ni40-xFexP20 (x = 0-17.5) alloys. For Pd40Ni40P20 (x = 0), the magnetic susceptibility consists of temperature-independent and Curie-Weiss-type terms. Alloys with x greater than or equal to 5 are paramagnetic at high temperatures. With decreasing temperature, the amorphous alloys become superparamagnetic. At even lower temperatures, and under a weak applied magnetic field, these alloys are spin glasses, as evidenced by static and dynamic magnetic measurements. The spin-freezing temperature increases with increasing iron content and this is attributed to the role of the Ruderman-Kittel-Kasuya-Yosida interaction in creating the spin-glass state. The occurrence of a reentrant spin-glass behavior on cooling (superparamagnetism-to-ferromagnetism-to-spin-glass transition) is also observed for x = 17.5 at a field greater than or equal to 50 Oe. An unexpected result is that the ferromagnetic state in the present bulk metallic glasses is field induced. Evidence for the field-induced ferromagnetic-like order is obtained from (a) straight regions in the susceptibility versus temperature curves measured at various fields, (b) an Arrott plot, and (c) time-independent magnetization. With increasing applied field, the spin-freezing temperature decreases and the Curie temperature increases, broadening the temperature range of the field-induced ferromagnetic-like state. The temporal decay of the thermoremanent magnetization in the amorphous alloy with x = 17.5 is slower than that in typical crystalline spin glasses. The spin-freezing temperature of the amorphous alloy with x = 17.5 decreases approximately logarithmically with applied field, which differs from the prediction of Neel's model for spin glasses. (C) 1999 American Institute of Physics. [S0021-8979(99)01108-1]. 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, Mail Stop G755, Los Alamos, NM 87545 USA. NR 73 TC 29 Z9 32 U1 4 U2 16 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 APR 15 PY 1999 VL 85 IS 8 BP 4110 EP 4119 DI 10.1063/1.370319 PN 1 PG 10 WC Physics, Applied SC Physics GA 188LN UT WOS:000079848600026 ER PT J AU Nagatomi, T Shimizu, R Ritchie, RH AF Nagatomi, T Shimizu, R Ritchie, RH TI Effective energy-loss functions for oxygen-adsorbed amorphous silicon surfaces SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRON-SPECTROSCOPY; QUANTITATIVE-ANALYSIS; LOSS SPECTRA; INELASTIC-SCATTERING; MODEL; PHOTOELECTRONS; PHOTOEMISSION; DEPENDENCE; METALS; SOLIDS AB Effective energy-loss functions were derived for oxygen-adsorbed amorphous silicon surfaces from a reflection electron energy-loss spectroscopy analysis based on the extended Landau theory. This study has revealed that the intensity of the surface-plasmon-loss peak for a clean surface decreases and its peak position shifts towards the lower-energy losses as oxygen exposure proceeds (less than or equal to 1000 L). To understand the above behavior of the surface-plasmon-loss peak, the distribution of the energy losses was calculated using the hydrodynamic model. The decrease and shift of the surface-plasmon-loss peak has been described with considerable success by assuming that the quasifree static electron density in the vicinity of the silicon surface decreases as oxygen adsorption proceeds owing to oxygen's high electron affinity. (C) 1999 American Institute of Physics. [S0021-8979(99)00908-1]. C1 Osaka Univ, Fac Engn, Dept Appl Phys, Osaka 5650871, Japan. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Nagatomi, T (reprint author), Osaka Univ, Fac Engn, Dept Appl Phys, Osaka 5650871, Japan. NR 32 TC 17 Z9 17 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 APR 15 PY 1999 VL 85 IS 8 BP 4231 EP 4237 DI 10.1063/1.370335 PN 1 PG 7 WC Physics, Applied SC Physics GA 188LN UT WOS:000079848600042 ER PT J AU Mitchell, JF Millburn, JE Medarde, M Argyriou, DN Jorgensen, JD AF Mitchell, JF Millburn, JE Medarde, M Argyriou, DN Jorgensen, JD TI Layered manganites: Magnetic structure at extreme doping levels SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID GIANT MAGNETORESISTANCE; OXYGEN STOICHIOMETRY; CRYSTAL-STRUCTURE; PEROVSKITE; LA1.2SR1.8MN2O7; LA1-XSRXMNO3; OXIDES AB We report powder neutron diffraction results on the crystal and magnetic structures of the bilayer Ruddlesden-Popper phase Sr3Mn2O7-delta(delta = 0.0, 0.45) and correlate these structures with their magnetic and transport properties. The delta = 0.45 compound contains a large number of oxygen vacancies that are disordered in the MnO2 planes. As a result of this disordered vacancy structure, Sr3Mn2O6.55 is a nonmagnetic insulator. Sr3Mn2O7.0(delta = 0) is an antiferromagnetic insulator whose magnetic structure is related to that of the SrMnO3 perovskite. Comparison of this end-member compound to its doped congeners in the La2-2xSr1+2xMn2O7 series highlights the extreme sensitivity of magnetic structure to dopant concentration in these layered materials. (C) 1999 American Institute of Physics. [S0021-8979(99)18608-0]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Mitchell, JF (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 29 TC 27 Z9 28 U1 1 U2 17 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 APR 15 PY 1999 VL 85 IS 8 BP 4352 EP 4354 DI 10.1063/1.370498 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700024 ER PT J AU Pasquale, M Bertotti, G Jiles, DC Bi, Y AF Pasquale, M Bertotti, G Jiles, DC Bi, Y TI Application of the Preisach and Jiles-Atherton models to the simulation of hysteresis in soft magnetic alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB This article describes the advances in unification of model descriptions of hysteresis in magnetic materials and demonstrates the equivalence of two widely accepted models, the Preisach (PM) and Jiles-Atherton (JA) models. Recently it was shown that starting from general energy relations, the JA equation for a loop branch can be derived from PM. The unified approach is here applied to the interpretation of magnetization measured in nonoriented Si-Fe steels with variable grain size [s], and also in as-cast and annealed Fe amorphous alloys. In the case of NO Fe-Si, the modeling parameter k defined by the volume density of pinning centers is such that k approximate to A+B/[s], where the parameters A and B are related to magnetocrystalline anisotropy and grain texture. The value of k in the amorphous alloys can be used to estimate the microstructural correlation length playing the role of effective grain size in these materials. (C) 1999 American Institute of Physics. [S0021-8979(99)23808-X]. C1 Ist Elettrotecn Nazl Galileo Ferraris, I-10125 Turin, Italy. INFM, I-10125 Turin, Italy. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Pasquale, M (reprint author), Ist Elettrotecn Nazl Galileo Ferraris, Corso Massimo DAzeglio 42, I-10125 Turin, Italy. RI Jiles, David/H-9548-2012; Pasquale, Massimo/I-8390-2012 OI Pasquale, Massimo/0000-0002-8336-1391 NR 6 TC 11 Z9 12 U1 1 U2 5 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 APR 15 PY 1999 VL 85 IS 8 BP 4373 EP 4375 DI 10.1063/1.369788 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700031 ER PT J AU Brown, GW Hawley, ME Markiewicz, DJ Spaepen, F Barth, EP AF Brown, GW Hawley, ME Markiewicz, DJ Spaepen, F Barth, EP TI Magnetic structure of deformation-induced shear bands in amorphous Fe80B16Si4 observed by magnetic force microscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID METAL RIBBONS; DOMAINS AB Processing-induced magnetic structures in amorphous metallic alloys are of interest because of their impact on the performance of materials used in electric device applications. Plastic deformation associated with cutting or bending the material to the desired shape occurs through the formation of shear bands. The stress associated with these shear bands induces magnetic domains that can lead to power losses through interaction with the fields and currents involved in normal device operation. These domains have been studied previously using a variety of techniques capable of imaging magnetic domain structures. In an effort to better characterize and understand these issues, we have applied atomic and magnetic force microscopy to these materials to provide three-dimensional nanometer-scale topographic resolution and micrometer-scale magnetic resolution. (C) 1999 American Institute of Physics. [S0021-8979(99)76508-4]. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Brown, GW (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RI Milliron, Delia/D-6002-2012 NR 12 TC 5 Z9 5 U1 1 U2 5 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 APR 15 PY 1999 VL 85 IS 8 BP 4415 EP 4417 DI 10.1063/1.369802 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700045 ER PT J AU Charlton, T Lederman, D Yusuf, SM Felcher, GP AF Charlton, T Lederman, D Yusuf, SM Felcher, GP TI Anisotropy of the sublattice magnetization and magnetoresistance in Co/Re superlattices on Al2O3(11(2)over-bar0) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID CO-RE SUPERLATTICES; GIANT MAGNETORESISTANCE; EXCHANGE; FE/CR(211) AB [Co(20 Angstrom)/Re(6 Angstrom)](20) superlattices were grown on a (11 (2) over bar 0) surface of a Al2O3 single crystal, with the [0001] direction of their hcp structure in the plane of the film. The Co layers were found to be antiferromagnetically coupled (AF), with a saturating field of 6 kOe. Polarized neutron reflectivity was used to determine the direction of the sublattice magnetization. In zero applied field, the AF moments are aligned along the Co[0001] axis. In a magnetic field H perpendicular to the Co[0001] axis, the sublattices moments evolve to a canted arrangement, with the AF component always perpendicular to the field. With H along the Co[0001] axis, the AF moments flop in a direction perpendicular to Co[0001] axis. The spin flop transition is not abrupt, but can be described as a gradual rotation that is completed at 2 kOe. The anisotropy of the sublattice magnetization is related to the anisotropy of the magnetoresistance. This has the conventional dumbbell behavior with the field applied perpendicular to the Co[0001] axis, but exhibits an extended plateau near H=0, and a slight increase up to H similar to 2 kOe, when H is parallel to Co[0001] axis. (C) 1999 American Institute of Physics. [S0021-8979(99)18708-5]. C1 W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Charlton, T (reprint author), W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. NR 14 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4436 EP 4438 DI 10.1063/1.370366 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700052 ER PT J AU Zvezdin, AK Dobrovitski, VV Harmon, BN Katsnelson, MI AF Zvezdin, AK Dobrovitski, VV Harmon, BN Katsnelson, MI TI Quantum fluctuations in the vicinity of the spin-flop transition in large-spin clusters SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETIC-RELAXATION; SINGLE-CRYSTAL; MOLECULES; NANOMAGNET AB If a single-spin possessing an easy-axis anisotropy is subjected to an external field perpendicular to the easy axis, the susceptibility exhibits a peculiar peak. We establish that the specific spectral properties of quantum fluctuations give rise to this peak. We predict that this effect takes place in real many-spin systems, such as Mn-12 clusters, and can be studied at finite temperatures in real experiments with attainable resolution. For studying quantum fluctuations in magnetic molecules, this offers an approach as an alternative to relaxation rate measurements. (C) 1999 American Institute of Physics. [S0021-8979(99)39208-2]. C1 Moscow Gen Phys Inst, Moscow 117942, Russia. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Russian Acad Sci, Inst Met Phys, Ekaterinburg 620219, Russia. RP Zvezdin, AK (reprint author), Moscow Gen Phys Inst, Moscow 117942, Russia. RI Katsnelson, Mikhail/D-4359-2012; Zvezdin, Anatoly/K-2072-2013 NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4530 EP 4532 DI 10.1063/1.370398 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700084 ER PT J AU Katsnelson, MI Dobrovitski, VV Harmon, BN AF Katsnelson, MI Dobrovitski, VV Harmon, BN TI Many-spin model and the spin Hamiltonian of Mn-12 clusters SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETIZATION; NANOMAGNET; MOLECULES AB In this work, we study the many-spin interactions taking place in Mn-12 large-spin clusters using the eight-spin model Hamiltonian, for which we determine the possible parameters based on experimental data. Account of the many-spin excitations satisfactorily explains positions of the neutron scattering peaks, results of electron paramagnetic resonance measurements and the temperature dependence of magnetic susceptibility. Among others, strong Dzyaloshinsky-Morya interactions are found to be important for description of neutron scattering data. These interactions can be important for the relaxation of the magnetization in Mn-12 clusters. (C) 1999 American Institute of Physics. [S0021-8979(99)63708-2]. C1 Russian Acad Sci, Inst Met Phys, Ekaterinburg 620219, Russia. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Katsnelson, MI (reprint author), Russian Acad Sci, Inst Met Phys, Ekaterinburg 620219, Russia. RI Katsnelson, Mikhail/D-4359-2012 NR 8 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4533 EP 4535 DI 10.1063/1.370399 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700085 ER PT J AU Oparin, AB Nicholson, DMC Zhang, XG Butler, WH Shelton, WA Stocks, GM Wang, Y AF Oparin, AB Nicholson, DMC Zhang, XG Butler, WH Shelton, WA Stocks, GM Wang, Y TI Magnetic structure at copper-permalloy interfaces SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB First principles local spin density calculations of the magnetic structure of interdiffused Cu/Py multilayers were performed. It was possible to solve the Kohn-Sham [Phys. Rev. 140, A1133 (1965)] equations for both canted and collinear magnetic arrangements to a high level of convergence. We found multiple, metastable, noncollinear magnetic structures that showed a reduced contribution to the saturation magnetization consistent with roughly one "magnetic dead" layer per interface. These canted interface layers were stable with respect to collinear interfaces by about 2 mRy per atom at the interface. The calculated noncollinear total spin magnetic moments as a function of the number of Py layers were in good agreement with the experiment. (C) 1999 American Institute of Physics. [S0021-8979(99)73708-4]. C1 Univ Tennessee, Oak Ridge, TN 37830 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Pittsburgh Supercomp Ctr, Pittsburgh, PA 15213 USA. RP Oparin, AB (reprint author), Univ Tennessee, Oak Ridge, TN 37830 USA. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 7 TC 13 Z9 13 U1 0 U2 5 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 APR 15 PY 1999 VL 85 IS 8 BP 4548 EP 4550 DI 10.1063/1.370403 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700090 ER PT J AU Berger, A Pufall, MR AF Berger, A Pufall, MR TI Quantitative vector magnetometry using generalized magneto-optical ellipsometry SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB We recently developed the method of generalized magneto-optical ellipsometry (GME), which enabled us to achieve a complete magneto-optical characterization of a magnetic material, including the magnetization orientation. For the present study, we have modified our original setup to allow for measurements at arbitrary external fields including entire field scans. Consequently, GME can be used as a tool to perform vector magnetometry measurements. In this article, we present our first experimental results on polycrystalline Co films which demonstrate the feasibility of GME as a magneto-optical vector magnetometer. (C) 1999 American Institute of Physics. [S0021-8979(99)41608-1]. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 92093 USA. RP Berger, A (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Berger, Andreas/D-3706-2015 OI Berger, Andreas/0000-0001-5865-6609 NR 6 TC 29 Z9 29 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 APR 15 PY 1999 VL 85 IS 8 BP 4583 EP 4585 DI 10.1063/1.370415 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700102 ER PT J AU Osgood, RM Sinha, SK Freeland, JW Idzerda, YU Bader, SD AF Osgood, RM Sinha, SK Freeland, JW Idzerda, YU Bader, SD TI X-ray scattering from magnetic, rough surfaces SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB We present expressions for the resonant magnetic x-ray scattering from rough surfaces; using our formulas we analyze the structural and magnetic roughnesses, as well as the correlation between them. We demonstrate that the leading contribution to the difference in the diffuse scattering between left- and right-circularly polarized light for a rough surface with in-plane magnetization vanishes unless the structural and magnetic roughnesses are correlated. The effects of magnetic domain structure and magnetic dead layers on the surface scattering are also discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)70108-8]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. USN, Res Lab, Div Sci Mat, Washington, DC 20379 USA. RP Osgood, RM (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013 NR 9 TC 35 Z9 35 U1 1 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 APR 15 PY 1999 VL 85 IS 8 BP 4619 EP 4621 DI 10.1063/1.370426 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700113 ER PT J AU Girt, E Altounian, Z Swainson, IP Krishnan, KM Thomas, G AF Girt, E Altounian, Z Swainson, IP Krishnan, KM Thomas, G TI Anomalous thermal expansion in Nd2Fe17-delta Ga delta (delta = 0-2) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID NEUTRON-DIFFRACTION AB In Nd2Fe17-deltaGadelta (delta=0, 0.5, 1, 1.5, 2), Ga substitutes for Fe without changing the crystal structure. Neutron diffraction measurements show that Ga preferentially substitutes for Fe in the 18 h sites only. The magnetic moments in Nd2Fe17-deltaGadelta, below the Curie temperature, T-c, are found to be in the basal plane. Below T-c the unit cell constant, c, decreases with increasing temperature for Nd2Fe17-deltaGadelta (delta less than or equal to 1). For Nd2Fe17-deltaGadelta (delta>1), the thermal expansion coefficient changes sign and becomes positive for Nd2Fe17-deltaGadelta. The relative decrease in the Fe(6c) - Fe( 6c) distance is twice as large as the decrease in the c axis below T-c. Below T-c, the Fe(6c) - Fe(6c) distance decreases with an increase in the Ga concentration, while above T-c the Fe(6c) - Fe(6c) distances are found to be independent on Ga concentration indicating that the presence of Ga decreases the negative exchange coupling between Fe atoms. (C) 1999 American Institute of Physics. [S0021-8979(99)56408-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. McGill Univ, Ctr Phys Mat, Dept Phys, Montreal, PQ H3A 2T8, Canada. AECL, Neutron & Condensed Matter Sci, Chalk River, ON K0J 1P0, Canada. RP Girt, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Altounian, Zaven/A-2073-2008 NR 3 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4669 EP 4671 DI 10.1063/1.370442 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700130 ER PT J AU Freitag, AE Chowdhury, AR AF Freitag, AE Chowdhury, AR TI Magnetic properties of Fe/Tb multilayers with large Fe layer thickness SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID AMORPHOUS TB-FE; METAL NANOSCALE MULTILAYERS; TB/FE MULTILAYERS; THIN-FILMS; ANISOTROPY AB Fe/Tb multilayers that display significant perpendicular magnetic anisotropy (PMA) up to an Fe layer thickness of 55 Angstrom have been fabricated and examined for the first time (to the best knowledge of the authors). Two series of Fe/Tb multilayer samples with a wide range of Fe layer thickness ranging between 8 and 55 Angstrom and with constant Tb layer thickness of 6.5 and 11.5 Angstrom were fabricated by planar magnetron sputtering. The magnetic and structural properties of these samples were examined using x-ray diffraction, Mossbauer spectroscopy, and torque magnetometry. Mossbauer spectra show PMA of the Fe magnetic moments for samples that consist of Fe layers and mixed interfaces only. The formation of an unmixed Tb layer starting at about 12 Angstrom Tb layer thickness leads to parallel alignment of the Fe magnetic moments. PMA in such multilayers is induced by a mixed interface and maintained by the exchange interaction between adjacent Fe layers. The interfaces that induce PMA in Fe/Tb multilayers are very close in composition to that of TbFe2 for which maximum PMA was found in thin amorphous Fe-Tb films. (C) 1999 American Institute of Physics. [S0021-8979(99)51508-9]. C1 Univ Alaska, Dept Phys, Fairbanks, AK 99775 USA. RP Freitag, AE (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 16 TC 9 Z9 9 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4696 EP 4698 DI 10.1063/1.370451 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700139 ER PT J AU Ivanov, O Antropov, VP AF Ivanov, O Antropov, VP TI Molecular magnetism: Noncollinear ordering and spin dynamics SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID CLUSTERS AB We have developed a new approach for the calculation of electronic structure and magnetic properties in the framework of spin density functional theory for arbitrary magnetic systems. This approach is based on the wavelets technique. We present test calculations and compare with previously published results. As an application of the general formalism to the noncollinear case we consider the two limiting cases of itinerant and localized magnetic moments. The development of this method is a first step to perform ab initio spin dynamics for finite atomic systems. (C) 1999 American Institute of Physics. [S0021-8979(99)58408-9]. C1 Iowa State Univ Sci & Technol, Ames Lab, Dept Phys, Ames, IA 50011 USA. RP Ivanov, O (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Dept Phys, Ames, IA 50011 USA. RI Ivanov, Oleg/K-6597-2015 OI Ivanov, Oleg/0000-0002-7658-305X NR 12 TC 15 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4821 EP 4823 DI 10.1063/1.370493 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700181 ER PT J AU Ujfalussy, B Wang, XD Nicholson, DMC Shelton, WA Stocks, GM Wang, Y Gyorffy, BL AF Ujfalussy, B Wang, XD Nicholson, DMC Shelton, WA Stocks, GM Wang, Y Gyorffy, BL TI Constrained density functional theory for first principles spin dynamics SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FL SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID SYSTEMS AB Constrained density functional theory is used to formulate a theory of general noncollinear spin systems which makes it possible to implement first principles spin dynamics in a manner that is firmly grounded in density functional theory. At each time step, local constraining fields are calculated from a self-consistent algorithm. In addition to discussing the conceptual basis of the resulting constrained local moment model we illustrate the theory by explicit calculations for the relative rotation of the corner and body center moments of bcc iron. (C) 1999 American Institute of Physics. [S0021-8979(99)58508-3]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Pittsburgh Supercomp Ctr, Pittsburgh, PA 15213 USA. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. RP Ujfalussy, B (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. EM v6f@gmsis.ms.ornl.gov 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 8 TC 34 Z9 34 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4824 EP 4826 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700182 ER PT J AU van Schilfgaarde, M Antropov, VP AF van Schilfgaarde, M Antropov, VP TI First-principles exchange interactions in Fe, Ni, and Co SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID BAND THEORY; IRON AB Using a multiple-scattering approach and the local-density and rigid-spin approximations, the exchange interactions are calculated for Fe, Ni, and Co, and the spin-wave spectrum obtained. The interactions contributing to the spin-wave spectrum are found to be rather long-ranged. The exchange parameters are calculated as a function of band filling, and predict transition to antiferromagnetic behavior for electron-deficient alloys of bcc Fe and fcc Co. (C) 1999 American Institute of Physics. [S0021-8979(99)58608-8]. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP van Schilfgaarde, M (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 9 TC 82 Z9 82 U1 2 U2 11 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 APR 15 PY 1999 VL 85 IS 8 BP 4827 EP 4829 DI 10.1063/1.370495 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700183 ER PT J AU Brown, RH Nicholson, DMC Wang, XD Schulthess, TC AF Brown, RH Nicholson, DMC Wang, XD Schulthess, TC TI First principles theory of spin waves in Fe, Co, and Ni SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FL SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID NICKEL AB Using constrained local spin density functional theory it is possible to directly calculate the adiabatic magnon dispersion curve. Small amplitude magnons with wavelengths between 2 and 32 atomic layers were constructed and the energy change with respect to amplitude within the frozen potential approximation was calculated. The resulting dispersion curves give the spin wave stiffness for [111] face-centered-cubic Co and Ni in fair agreement with experiment. In Fe the stiffness was calculated along [100] and [110] directions. The two values of stiffness were found to be nearly equal to each other and roughly half the measured value. It was found that the calculated Fe stiffness did not change upon addition of gradient corrections to the local density approximation, indicating that the source of discrepancy is not likely a failure of the local density approximation. It is argued that the adiabatic approximation is more likely the source of discrepancy since the magnetic interactions in Fe are longer ranged than those in Co or Ni, thus making the dynamical retardation effect more important in Fe. (C) 1999 American Institute of Physics. [S0021-8979(99)58708-2]. C1 Luther Coll, Dept Phys, Decorah, IA 52101 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Luther Coll, Dept Phys, Decorah, IA 52101 USA. EM dmn@ornl.gov NR 15 TC 12 Z9 12 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4830 EP 4832 DI 10.1063/1.370035 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700184 ER PT J AU MacLaren, JM Schulthess, TC Butler, WH Sutton, R McHenry, M AF MacLaren, JM Schulthess, TC Butler, WH Sutton, R McHenry, M TI Electronic structure, exchange interactions, and Curie temperature of FeCo SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ALLOYS; CO; METALS AB Fe-Co alloys in the alpha phase are soft magnetic materials which have high saturation inductions over a wide range of compositions. However, above about 1250 K, an alpha to gamma phase transition occurs. The fcc-based, gamma, high-temperature phase is paramagnetic at this temperature. In this work the low-temperature ordered B2, or alpha', phase, as well as the disordered bcc phase of FeCo alloys, have been studied with first-principles electronic-structure calculations using the layer Korringa-Kohn-Rostoker method. The variation of moment with composition (Slater-Pauling curve) is discussed. For equiatomic FeCo, interatomic exchange couplings are derived from first principles. These exchange interactions are compared to those obtained for pure Fe and Co, and are used within a mean-field theory to estimate the hypothetical Curie temperature of the alpha phase. (C) 1999 American Institute of Physics. [S0021-8979(99)76808-8]. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Carnegie Mellon Univ, Pittsburgh, PA 15123 USA. RP MacLaren, JM (reprint author), Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. RI McHenry, Michael/B-8936-2009 NR 14 TC 93 Z9 95 U1 7 U2 26 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 APR 15 PY 1999 VL 85 IS 8 BP 4833 EP 4835 DI 10.1063/1.370036 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700185 ER PT J AU Schulthess, TC Butler, WH Stocks, GM Maat, S Mankey, GJ AF Schulthess, TC Butler, WH Stocks, GM Maat, S Mankey, GJ TI Noncollinear magnetism in substitutionally disordered face-centered-cubic FeMn SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MANGANESE AB We use first principles electronic structure techniques to study the magnetic structure of gamma-FeMn using the Korringa-Kohn-Rostocker multiple-scattering approach in conjunction with an extension of the single site coherent potential approximation to noncollinear magnetic structures. Our results show that the noncollinear 3Q and 2Q structures are both stable solutions with the former being slightly lower in energy. The collinear solutions could only be converged in a traditional spin-polarized calculation and are unstable in a noncollinear treatment. (C) 1999 American Institute of Physics. [S0021-8979(99)59008-7]. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Univ Alabama, Tuscaloosa, AL 35487 USA. RP Schulthess, TC (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Mankey, Gary/G-9110-2011; Stocks, George Malcollm/Q-1251-2016 OI Mankey, Gary/0000-0003-3163-5159; Stocks, George Malcollm/0000-0002-9013-260X NR 10 TC 35 Z9 35 U1 2 U2 8 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 APR 15 PY 1999 VL 85 IS 8 BP 4842 EP 4844 DI 10.1063/1.370039 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700188 ER PT J AU Nakotte, H Laughlin, L Kawanaka, H Argyriou, DN Sheldon, RI Nishihara, Y AF Nakotte, H Laughlin, L Kawanaka, H Argyriou, DN Sheldon, RI Nishihara, Y TI Magnetic properties of single-crystalline Mott insulator YVO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB Single crystals of YVO3 were grown using the floating-zone technique. YVO3 crystallizes in the orthorhombic Pbnm structure, and the structural parameters were determined by means of neutron diffraction. Using a superconducting quantum interference device magnetometer, we have studied the magnetic properties of YVO3 along the three principal directions. Our single crystal exhibits two magnetic transitions at about 115 and 75 K. For temperatures above the magnetic ordering, almost isotropic Curie-Weiss behavior is found for the magnetic susceptibility. Below the ordering, however, we find a highly anisotropic response with the c axis as the easy-magnetization direction. Both magnetic phases exhibit a weak ferromagnetic component along the c axis. A complex low-field magnetization behavior indicates that YVO3 orders ferrimagnetically for temperatures between 75 and 115 K. (C) 1999 American Institute of Physics. [S0021-8979(99)59308-0]. C1 New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Electrotech Lab, Tsukuba, Ibaraki 3058568, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ibaraki Univ, Fac Sci, Mito, Ibaraki 310, Japan. RP Nakotte, H (reprint author), New Mexico State Univ, Dept Phys, MSC 3D, Las Cruces, NM 88003 USA. NR 9 TC 6 Z9 6 U1 1 U2 11 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 APR 15 PY 1999 VL 85 IS 8 BP 4850 EP 4852 DI 10.1063/1.370042 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700191 ER PT J AU Lewis, LH Panchanathan, V AF Lewis, LH Panchanathan, V TI Effect of the boron : rare-earth ratio on metastable phase formation in Nd2Fe14B-based nanocomposites SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETIC-PROPERTIES; PERMANENT-MAGNETS AB Magnetic nanocomposite alloys developed from amorphous precursors by annealing often exhibit metastable transition phases that ultimately control the kinetics of the nucleation and growth of the desired RE2Fe14B-type phase. It is thus important to understand the effect of starting composition on the formation of the metastable transition phases found in the nanocomposite system. The relationships between composition and the nature of metastable phase formation in the low-boron content melt-spun nanocomposite alloy Nd-2[Co-0.06(Fe1-xCrx)(0.94)](23.2)B-1.48 (0 less than or equal to x < 0.09) were studied and compared with results of other authors. The crystallization sequence undertaken by the quenched samples during annealing was followed by differential thermal analysis and x-ray diffraction. Differences in the nominal starting boron: RE compositional ratio of the alloy may produce significant changes in the nature and stability of the metastable phases present in the system. In general, a high compositional ratio (B:RE approximate to 1-4) promotes the initial formation of Fe3B and complex boron-rich intermetallic phases such as the cubic Nd2Fe23B3, the hexagonal NdFe12B6 and the cubic Y3Fe62B14-type phases in the quenched material, while a low compositional ratio (B:RE < 0.5) is favors the formation of alpha-Fe and a 2-17-type phase. It is suggested that the focus of further studies done to optimize the performance of these nanocomposite alloys should be on the effect that alloying additions have upon the metastable phases, and not on the final equilibrium phases. (C) 1999 American Institute of Physics. [S0021-8979(99)60008-1]. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. Magnequench Int Inc, Anderson, IN 46013 USA. RP Lewis, LH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. NR 13 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4883 EP 4885 DI 10.1063/1.369130 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700202 ER PT J AU Choi, HJ Kawakami, RK Escorcia-Aparicio, EJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Osgood, RM Bader, SD AF Choi, HJ Kawakami, RK Escorcia-Aparicio, EJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Osgood, RM Bader, SD TI Magnetic properties of ultrathin Fe films grown on stepped W(001) and Pd(001) substrates SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ANISOTROPY; SURFACE AB In both Fe/W(001) and Fe/Pd(001) systems, the atomic steps induce an in-plane uniaxial magnetic anisotropy with the easy magnetization axis perpendicular to the step edges. The strength of the step-induced anisotropy was found to have a power law dependence on the step density: a quadratic dependence in the Fe/W system but a linear dependence in the Fe/Pd system. In addition, the Curie temperature is found to be higher on the stepped surface in the Fe/Pd system as compared to the flat surface. The enhancement of the Curie temperature is attributed to the step-induced Pd moments which is supported by the increased surface magneto-optic Kerr effect signal on the stepped surface. No such enhancement of either Curie temperature or magnetic moment was observed in the Fe/W system. (C) 1999 American Institute of Physics. [S0021-8979(99)27608-6]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Choi, HJ (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Qiu, Zi Qiang/O-4421-2016; Bader, Samuel/A-2995-2013 OI Qiu, Zi Qiang/0000-0003-0680-0714; NR 9 TC 15 Z9 15 U1 1 U2 12 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 APR 15 PY 1999 VL 85 IS 8 BP 4958 EP 4960 DI 10.1063/1.370502 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700227 ER PT J AU Lo, CCH Scruby, CB AF Lo, CCH Scruby, CB TI Study of magnetization processes and the generation of magnetoacoustic and Barkhausen emissions in ferritic/pearlitic steel SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID PLAIN CARBON-STEELS; PEARLITIC STEELS AB Magnetoacoustic emission (MAE), Barkhausen emission (BE), and hysteresis loop measurements have been made on steel specimens heat treated to produce ferritic/pearlitic structures with various volume fractions of ferrite V-alpha. It was found that in the low-field region the BE activity decreases whereas the MAE signal increases with V-alpha. Increasing V-alpha also results in a decrease in the initial peak height of MAE profiles and the formation of outer peaks in BE profiles. It was observed by Lorentz microscopy that in ferrite non-180 degrees domain wall motion occurs readily in the low-field region, while in pearlite significant 180 degrees domain wall motion takes place only when a reversed field was applied. These results can account for the variations in the MAE and BE profiles with V-alpha. The sensitivity of the MAE and BE profiles to V-alpha enables both techniques to be exploited for monitoring the ferrite content of steel components. (C) 1999 American Institute of Physics. [S0021-8979(99)53408-7]. C1 Univ Oxford, Dept Mat, Oxford OX1 3PH, England. AEA Technol plc, Natl NDT Ctr, Abingdon OX14 3DB, Oxon, England. RP Lo, CCH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 8 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5193 EP 5195 DI 10.1063/1.369121 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700303 ER PT J AU Growney, E Friedman, G Gerald, R AF Growney, E Friedman, G Gerald, R TI Computation of distortions in magnetic field and spectrum for nuclear magnetic resonance instruments SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID SUSCEPTIBILITY DISTRIBUTIONS; NUMERICAL-ANALYSIS AB A method for highly accurate modeling of induced field distortions in nuclear magnetic resonance (NMR) is developed based on the partial field formulation of the magnetostatic problem and use of the surface integral equation technique. A bound for the error in the NMR spectrum dispersion computation is derived in terms of the energy norm error associated with the static field calculations. It is shown that distortion fields can be computed with sufficient accuracy in many NMR applications using only the equivalent sources induced by the applied uniform static field. (C) 1999 American Institute of Physics. [S0021-8979(99)75308-9]. C1 Univ Illinois, Dept Elect Engn & Comp Sci, Chicago, IL 60607 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Growney, E (reprint author), Univ Illinois, Dept Elect Engn & Comp Sci, Chicago, IL 60607 USA. NR 6 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5205 EP 5207 DI 10.1063/1.369125 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700307 ER PT J AU Li, DQ Diercks, V Pearson, J Jiang, JS Bader, SD AF Li, DQ Diercks, V Pearson, J Jiang, JS Bader, SD TI Structural and magnetic studies of fcc Fe films with self-organized lateral modulation on striped Cu(110)-O(2x1) substrates SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ULTRATHIN FILMS; CU(100); ANISOTROPY; CU(111); PHASES; WEDGES; CO AB Face-centered cubic (fcc) Fe wedges of 0-12 ML were grown by means of molecular beam epitaxy onto a novel substrate: flat Cu(110) with an oxygen-induced, long-range ordered striped phase, and studied in situ with medium energy electron diffraction (MEED) and the surface magneto-optical Kerr effect (SMOKE). In contrast to Fe growth on either clean or oxygen-saturated Cu(110), the films on the striped substrates retain a layer-by-layer growth mode up to 6-7 ML and are fcc at least up to 12 ML. In addition, satellite peaks were observed on both sides of the MEED (0, 0) streak, indicating a long-range-ordered lateral modulation of the Fe surface. We postulate that the Fe films grow conformally onto the original striped substrate. SMOKE studies show that these fcc Fe wedges are ferromagnetic with an easy axis along the original stripes for Fe thickness >4 ML and a remanant magnetization that increases linearly with thickness beyond 4 ML. 1999 American Institute of Physics. [S0021-8979(99)40408-6]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Li, DQ (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013 NR 14 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5285 EP 5287 DI 10.1063/1.370497 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500003 ER PT J AU Osborn, R Goremychkin, EA Sashin, IL Murani, AP AF Osborn, R Goremychkin, EA Sashin, IL Murani, AP TI Inelastic neutron scattering study of the spin dynamics of Yb1-xLuxAl3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID PARAMAGNETIC SPECTRAL RESPONSE; KONDO RESONANCE; COMPOUND YBAL3; CRYSTAL; GAP AB We present the results of a systematic inelastic neutron scattering study of the spin dynamics of the mixed valent compound YbAl3 doped with nonmagnetic lutetium. The aim of the investigation is to clarify the origin of the unusual gap-like magnetic response observed in YbAl3, which can be modeled by two inelastic peaks: a narrow peak at 34 meV with half width at half maximum, Gamma = 6.4 +/- 0.8 meV and a broad peak at 44 meV with Gamma = 30+/- 1 meV. Lutetium substitution leads to a substantial increase in the linewidth (Gamma = 9 +/- 1 meV at x = 0.1) and a decrease in the intensity (down by 60% at x = 0.1) of the narrow component, with a negligible effect on the broad inelastic peak. This trend is confirmed with higher doping resulting in the complete suppression of the narrow peak at x greater than or equal to 0.35. The results indicate that the narrow component arises from coherent excitation processes within the hybridized 4f band. (C) 1999 American Institute of Physics. [S0021-8979(99)54108-X]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Joint Inst Nucl Res, Frank Lab Neutron Phys, Dubna 141980, Moscow Region, Russia. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Osborn, R (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011 OI Osborn, Raymond/0000-0001-9565-3140 NR 18 TC 8 Z9 8 U1 3 U2 5 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 APR 15 PY 1999 VL 85 IS 8 BP 5344 EP 5346 DI 10.1063/1.370247 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500023 ER PT J AU Su, X Zuo, F Schlueter, JA Williams, JM AF Su, X Zuo, F Schlueter, JA Williams, JM TI Interlayer magnetoresistance peak in beta ''-(BEDT-TTF)(2)SF5CH2CF2SO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID C-AXIS RESISTIVITY; ORGANIC SUPERCONDUCTORS; FERMI-SURFACE; MIXED-STATE; JOSEPHSON; KAPPA-(BEDT-TTF)(2)CUBR; DISSIPATION; FIELD AB Transport measurements of interlayer magnetoresistance with the field parallel to the current direction have been performed on single crystals of organic superconductor beta''-(BEDT-TF)(2)SF5CH2CF2SO3. The magnetoresistance is found to display a pronounced peak as a function of magnetic field below the superconducting transition temperature, similar to those of kappa-(BEDT-TTF)(2)X compounds. Analysis of the magnetoresistance peak in terms of a simple pair and quasiparticle tunneling model gives a physically negligible gap energy. (C) 1999 American Institute of Physics. [S0021-8979(99)17008-7]. C1 Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Su, X (reprint author), Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. NR 26 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5353 EP 5355 DI 10.1063/1.370250 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500026 ER PT J AU Gschneidner, KA Pecharsky, VK AF Gschneidner, KA Pecharsky, VK TI Magnetic refrigeration materials (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ROOM-TEMPERATURE; ALLOYS; GD-5(SI2GE2) AB Research on the magnetocaloric effect and its application for cooling near room temperature over the past few years has helped to move this phenomenon from a scientific curiosity to an emerging technology. Two of the most important advances include the demonstration which proved that it is possible to obtain significant cooling powers (600 W) at high Carnot efficiencies (60%) and with a large coefficient of performance (15) near room temperature in moderately strong magnetic fields (less than or equal to 5 T); and the discovery of the giant magnetocaloric effect in the Gd-5(SixGe1-x)(4) series of alloys. Also, new knowledge about the magnetocaloric effect has been gained. This includes: the relationship between the nature of the magnetic transformation(s) and the temperature dependence of the magnetocaloric effect, the entropy utilized in the magnetocaloric process, and the role of impurities on the giant magnetocaloric effect. (C) 1999 American Institute of Physics. [S0021-8979(99)22108-1]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Gschneidner, KA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 19 TC 137 Z9 138 U1 5 U2 30 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 APR 15 PY 1999 VL 85 IS 8 BP 5365 EP 5368 DI 10.1063/1.369979 PN 2B PG 4 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500030 ER PT J AU Lin, CT Yan, Y Bischoff, E Peters, K Schonherr, E AF Lin, CT Yan, Y Bischoff, E Peters, K Schonherr, E TI Lead-doped single crystals of Ln(1-x-y)Sr(x)Pb(y)MnO(3) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID THIN-FILMS; MAGNETORESISTANCE; MANGANITES; TRANSITION AB Single crystals of Ln(1-x-y)Sr(x)Pb(y)MnO(3) (Ln: La, Pr, or Nd) with sizes up to 3 cm(3) have been obtained using a flux solution of PbF2 and PbO at the temperature range between 917 and 1300 degrees C. The content of Pb was found to range between 0.26 less than or equal to y less than or equal to 0.43, depending upon the growing temperature, i.e., the higher the temperature, the lower the Pb content. Transmission electron microscopy studies provided evidence of a nanostructural behavior for Nd0.67Sr0.01Pb0.32MnO3. The crystals exhibit a sharp transition of ferromagnetic metallic to paramagnetic insulating behavior. Resistance measurement was performed in a magnetic field of 0, 2 and 7 T, respectively. (C) 1999 American Institute of Physics. [S0021-8979(99)19708-1]. C1 Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Max Planck Inst Met Forsch, D-70174 Stuttgart, Germany. RP Lin, CT (reprint author), Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany. RI Bischoff, Ewald/J-3559-2012; OI Bischoff, Ewald/0000-0002-3976-5831 NR 13 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5393 EP 5395 DI 10.1063/1.369988 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500039 ER PT J AU Schulthess, TC Butler, WH AF Schulthess, TC Butler, WH TI Coupling mechanisms in exchange biased films (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FL SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID PERMALLOY/COO INTERFACES; MAGNETIC-PROPERTIES; FEF2-FE BILAYERS; ANISOTROPY; MODEL AB We use an atomistic Heisenberg model in conjunction with the classical Landau Lifshitz equation for the spin motion to study coupling mechanisms between ferromagnetic (FM) and antiferromagnetic (AFM) films. Calculations for CoO/FM illustrate that there are two coupling mechanisms at work, the spin-flop coupling and an AFM-FM coupling through uncompensated defects. While the latter accounts for exchange bias and related phenomena, the former gives rise to a large coercivity and perpendicular alignment between FM spins and AFM easy axis. A combination of the two mechanisms explains apparent discrepancies between reversible and irreversible measurements of the AFM-FM coupling. (C) 1999 American Institute of Physics. [S0021-8979(99)31508-5]. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. EM schulthesstc@ornl.gov NR 31 TC 120 Z9 120 U1 2 U2 20 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5510 EP 5515 DI 10.1063/1.369878 PN 2B PG 6 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500078 ER PT J AU Zhong, YC Sarachik, MP Friedman, JR Robinson, RA Kelley, TM Nakotte, H Christianson, AC Trouw, F Aubin, SMJ Hendrickson, DN AF Zhong, YC Sarachik, MP Friedman, JR Robinson, RA Kelley, TM Nakotte, H Christianson, AC Trouw, F Aubin, SMJ Hendrickson, DN TI Inelastic neutron scattering study of Mn-12-acetate SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID HIGH-SPIN MOLECULES; SINGLE-CRYSTAL; MAGNETIZATION; SUSCEPTIBILITY; RELAXATION; MN12AC AB We report zero-field inelastic neutron scattering experiments on a deuterated powder sample of Mn 12-acetate consisting of a large number of nominally identical spin-10 magnetic clusters. Our resolution enables us to see a series of peaks corresponding to transitions between the anisotropy levels within the spin-10 manifold. A fit to the spin Hamiltonian H = -DSz2 - mu B B.g.S - AS(z)(4) +C(S-+(4) +S--(4)) yields an anisotropy constant D=(0.54+/-0.02) K and a fourth-order diagonal anisotropy coefficient A=( 1.2+/-0.1) X 10(-3) K (the other terms being negligible). Performed in the absence of a magnetic field, our experiments do not involve the g values as fitting parameters, thereby yielding particularly reliable values of D and A. (C) 1999 American Institute of Physics. [S0021-8979(99)65508-6]. C1 CUNY City Coll, Dept Phys, New York, NY 10031 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Sci Ctr, Los Alamos, NM 87545 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. RP Zhong, YC (reprint author), CUNY City Coll, Dept Phys, New York, NY 10031 USA. RI Friedman, Jonathan/A-6323-2008; Lujan Center, LANL/G-4896-2012; christianson, andrew/A-3277-2016 OI Friedman, Jonathan/0000-0003-3614-4623; christianson, andrew/0000-0003-3369-5884 NR 18 TC 50 Z9 50 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 APR 15 PY 1999 VL 85 IS 8 BP 5636 EP 5638 DI 10.1063/1.369824 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500117 ER PT J AU Matsuda, M Katsumata, K Shapiro, SM Shirane, G AF Matsuda, M Katsumata, K Shapiro, SM Shirane, G TI Magnetic excitations in the S = 1/2 quasi-one-dimensional magnet Sr14-xCaxCu24O41 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID SPIN LADDERS; MATERIAL SR14CU24O41; DYNAMICS; SYSTEM; NMR; GAP; CHAINS; STATE AB Neutron scattering experiments have been performed on Sr14-xCaxCu24O41 (x=3 and 6), which consists of CuO2 chains and Cu2O3 ladders, in order to study the effect of Ca substitution on the dimerized state in the chains. The Ca substitution broadens the excitation peak although the excitation energy is almost unchanged. The effects of Ca and Y substitution on the dimerized state are compared. (C) 1999 American Institute of Physics. [S0021-8979(99)28008-5]. C1 RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Matsuda, M (reprint author), RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. RI Matsuda, Masaaki/A-6902-2016 OI Matsuda, Masaaki/0000-0003-2209-9526 NR 20 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5642 EP 5644 DI 10.1063/1.369826 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500119 ER PT J AU Snyder, JE Lo, CCH Fang, X Kriegermeier, B Jiles, DC AF Snyder, JE Lo, CCH Fang, X Kriegermeier, B Jiles, DC TI Microstructure and magnetic properties of as-quenched and heat-treated (Nd,Dy)FeB powders produced by high pressure gas atomization SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID PERMANENT-MAGNETS; ALLOYS; FE; ND AB The magnetic properties and microstructures of a series of as-quenched and heat-treated inert gas atomized (IGA) rare-earth rich (Nd,Dy)-Fe-B particles have been investigated. Heat treatment was found to substantially improve magnetic properties, with effects most pronounced in samples with higher Dy content and higher total rare earth (RE) content. The as-quenched particles consisted of an underquenched dendritic-like structure with the majority phase RE2Fe14B, and a fine network of RE-rich material between the grains. The heat-treated particles showed a change in microstructure which correlated with magnetic property changes. Particles which showed little change in magnetic properties showed no obvious change in microstructure. Particles which showed large changes in magnetic properties showed a large change in microstructure: most of the fine network of RE-rich interdendritic material disappeared, leaving behind only a few small isolated regions. This would seem to indicate that the predominant mechanism determining coercivity in these IGA RE-rich (Nd,Dy)-Fe-B powers is nucleation of reverse domains, rather than domain wall pinning at nonmagnetic intergranular material. (C) 1999 American Institute of Physics. [S0021-8979(99)44708-5]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Snyder, JE (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Jiles, David/H-9548-2012 NR 13 TC 2 Z9 2 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5678 EP 5680 DI 10.1063/1.369838 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500131 ER PT J AU Freitag, AE Chowdhury, AR AF Freitag, AE Chowdhury, AR TI Influence of the phase transition of Tb on the magnetic properties of Fe/Tb multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ARTIFICIALLY LAYERED STRUCTURE; METAL NANOSCALE MULTILAYERS; THIN-FILMS; ANISOTROPY; TB/FE; FE AB The impact of the phase transition between para- and ferromagnetic states of Tb on the magnetic properties of Fe/Tb multilayers has been studied by taking low temperature Mossbauer measurements. 26 Fe/Tb multilayer samples with a wide range of thickness were fabricated by planar magnetron sputtering on polyester and glass substrates. The magnetic and structural properties of these samples were examined using x-ray diffraction, Mossbauer spectroscopy, and torque magnetometry. At room temperature, Mossbauer spectra show perpendicular magnetic anisotropy (PMA) of the Fe magnetic moments for samples that consist of Fe layers and mixed interfaces only. The formation of an unmixed Tb layer starting at about 12 Angstrom Tb layer thickness leads to parallel alignment of the Fe magnetic moments. For samples for which discrete Tb layers are formed, these Tb layers are probably paramagnetic at room temperature as can be deduced from low temperature Mossbauer measurements and room temperature torque measurement. The hyperfine field of Fe in these multilayers as determined from Mossbauer spectroscopy shows a relative minimum around the Curie temperature of Tb of 220 K indicating reorientation of the Fe moments due to spin polarization of Tb. (C) 1999 American Institute of Physics. [S0021-8979(99)46008-6]. C1 Univ Alaska Fairbanks, Fairbanks, AK 99775 USA. RP Freitag, AE (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 13 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5756 EP 5758 DI 10.1063/1.370116 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500157 ER PT J AU Butler, WH Zhang, XG Schulthess, TC Nicholson, DMC Oparin, AB MacLaren, JM AF Butler, WH Zhang, XG Schulthess, TC Nicholson, DMC Oparin, AB MacLaren, JM TI First principles modeling of magnetic random access memory devices (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID GIANT MAGNETORESISTANCE; ELECTRICAL-CONDUCTIVITY; ELECTRONIC-STRUCTURE; SPIN VALVES; MULTILAYERS; TRANSPORT; SCATTERING; INTERFACE AB Giant magnetoresistance (GMR) and spin-dependent tunneling may be used to make magnetic random access memory devices. We have applied first-principles based electronic structure techniques to understand these effects and in the case of GMR to model the transport properties of the devices. (C) 1999 American Institute of Physics. [S0021-8979(99)77608-5]. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Tulane Univ, Dept Phys, New Orleans, LA 70018 USA. RP Butler, WH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 19 TC 27 Z9 27 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5834 EP 5839 DI 10.1063/1.369933 PN 2B PG 6 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500181 ER PT J AU Lohstroh, W Munzenberg, M Felsch, W Fritzsche, H Maletta, H Goyette, R Felcher, GP AF Lohstroh, W Munzenberg, M Felsch, W Fritzsche, H Maletta, H Goyette, R Felcher, GP TI Imprinting artificial magnetic structures (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB Recently we created La/Fe multilayers with a helical magnetic structure imprinted from the conditions of growth rather than by the magnetic interactions between layers. Each sublayer was 30 Angstrom thick, and during deposition the sample was rotated in an external field of 3 Oe, a field strong enough to magnetize the Fe layer being deposited but not sufficient to perturb the magnetization of the Fe layers already grown. As a result adjacent Fe layers formed a helical structure with a chirality and periodicity determined by the rotational direction and speed of the substrate and the rate of deposition. Following this discovery an extensive set of experiments (mainly using Kerr effect magnetometry and polarized neutron reflectivity) was undertaken to ascertain the stability of imprinted magnetic structures, and to understand the onset of magnetization during growth. La/Fe imprinted helical magnetic structures (of different La and Fe thicknesses) were found to be stable in time and to be permanently erased only by magnetic fields larger than 90 Oe. (C) 1999 American Institute of Physics. [S0021-8979(99)67408-4]. C1 Univ Gottingen, Inst Phys 1, D-37073 Gottingen, Germany. Hahn Meitner Inst Berlin, D-14109 Berlin, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. RP Lohstroh, W (reprint author), Univ Gottingen, Inst Phys 1, D-37073 Gottingen, Germany. RI Munzenberg, Markus/B-1251-2010; OI Munzenberg, Markus/0000-0002-1332-5678; Fritzsche, Helmut/0000-0001-5288-8302 NR 7 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5873 EP 5876 DI 10.1063/1.369945 PN 2B PG 4 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500193 ER PT J AU Fishman, RS AF Fishman, RS TI Helical spin-density waves in Fe/Cr trilayers with perfect interfaces SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID OSCILLATION PERIODS; CHROMIUM-ALLOYS; PHASE-DIAGRAM; SUPERLATTICES; ANTIFERROMAGNETISM; MULTILAYERS AB Despite the presence of only collinear, commensurate (C) and incommensurate (I) spin-density waves (SDWs) in bulk Cr, the interfacial steps in Fe/Cr multilayers are now believed to stabilize a helical (H) SDW within the Cr spacer. Yet HSDWs were first predicted in an Fe/Cr trilayer with perfect interfaces when the orientation of the Fe moments does not favor C ordering: if the number of Cr monolayers is even (odd) and the Fe moments are pointing in the same (opposite) direction, then a CSDW does not gain any coupling energy. Under these circumstances, a simple model verifies that H ordering is indeed favored over I ordering provided that the Fermi surface mismatch is sufficiently small or the temperature sufficiently high. (C) 1999 American Institute of Physics. [S0021-8979(99)67508-9]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Fishman, RS (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Fishman, Randy/C-8639-2013 NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5877 EP 5879 DI 10.1063/1.369900 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500194 ER PT J AU You, CY Sowers, CH Inomata, A Jiang, JS Bader, SD Koelling, DD AF You, CY Sowers, CH Inomata, A Jiang, JS Bader, SD Koelling, DD TI Oscillation period of the interlayer coupling for epitaxial Fe/Cr1-xVx(100) and (211) superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FL SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID FE/CR MULTILAYERS; GIANT MAGNETORESISTANCE AB The microscopic origin of the 18 Angstrom period in the oscillatory interlayer exchange coupling of Fe/Cr(100) and (211) superlattices is investigated by alloying the Cr spacer with V to alter its Fermi surface. The addition of V increases or decreases in size the various Fermi surface calipers that are candidates for governing the oscillation period, such as those that span the ellipse, lens, octahedron, and nested sheets. Epitaxial sputtered superlattices of (100) and (211) orientation were grown and characterized via magnetoresistance measurements as a function of spacer layer thickness for different V-doping levels. A small decrease of the oscillation period is found experimentally which strongly implicates the N-centered ellipse as the origin of the 18 Angstrom period in Fe/Cr superlattices. (C) 1999 American Institute of Physics. [S0021-8979(99)67908-7]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. EM cyyou@anl.gov RI You, Chun-Yeol/B-1734-2010; Bader, Samuel/A-2995-2013 OI You, Chun-Yeol/0000-0001-9549-8611; NR 16 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5889 EP 5891 DI 10.1063/1.369904 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500198 ER PT J AU Grimsditch, M Camley, R Fullerton, EE Jiang, S Bader, SD Sowers, CH AF Grimsditch, M Camley, R Fullerton, EE Jiang, S Bader, SD Sowers, CH TI Exchange-spring systems: Coupling of hard and soft ferromagnets as measured by magnetization and Brillouin light scattering (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETS; BILAYERS; FILMS; BEHAVIOR AB An experimental and theoretical study is presented of the normal magnetic modes in spiral ferromagnetic structures. The bilayer system studied consists of Fe layers (25, 50, 100, and 200 Angstrom thick) that are exchange coupled to 200 Angstrom thick SmCo films that have approximate to 200 kOe anisotropies. The Fe spiral-induced by an external magnetic field that is applied opposite to the direction of the magnetized film-results in a structure similar to that encountered in a Bloch domain wall. The magnetization and the field dependence of the magnons in various Fe films are explained by the theoretical model. (C) 1999 American Institute of Physics. [S0021-8979(99)47008-2]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Colorado, Dept Phys, Colorado Springs, CO 80933 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. RP Grimsditch, M (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013; Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 14 TC 45 Z9 45 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 APR 15 PY 1999 VL 85 IS 8 BP 5901 EP 5904 DI 10.1063/1.369908 PN 2B PG 4 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500202 ER PT J AU Branagan, DJ Kramer, MJ Tang, YL McCallum, RW AF Branagan, DJ Kramer, MJ Tang, YL McCallum, RW TI Maximizing loop squareness by minimizing gradients in the microstructure SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ND2FE14B; SYSTEM AB Enhanced energy product and higher operating fields can be achieved by improving the squareness of the demagnetization loop. In isotropic materials, increasing loop squareness can be achieved by minimizing microstructural gradients and maximizing homogeneity. Achieving homogeneity by melt spinning can be difficult due to localized changes in cooling conditions from extrinsic factors such as gas entrapment between the melt and the chill surface and intrinsic effects resulting from the stochastic nature of nucleation on a surface. These localized variations are reduced by altering the solidification kinetics of the alloy, thus reducing its sensitivity to localized changes in cooling conditions. This was achieved through development of a nine-element modified Nd-Fe-B alloy which solidified with a uniform glass structure at much lower cooling rates. After crystallization, enhanced microstructural homogeneity was verified by electron microscopy and described by parameters based on the loop shape. The nine-element alloy had squarer loops and uniformly high hard magnetic properties (>12 MG Oe) for cooling rates over 10 m/s. (C) 1999 American Institute of Physics. [S0021-8979(99)47708-4]. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Branagan, DJ (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, 2351 N Blvd, Idaho Falls, ID 83415 USA. NR 6 TC 10 Z9 10 U1 1 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 APR 15 PY 1999 VL 85 IS 8 BP 5923 EP 5925 DI 10.1063/1.369915 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500209 ER PT J AU Lewis, LH Gallagher, K Panchanathan, V AF Lewis, LH Gallagher, K Panchanathan, V TI The effect of Nb additions on the thermal stability of melt-spun Nd2Fe14B SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID FE-B MAGNETS; PHASES; ALLOYS AB Elevated-temperature superconducting quantum interference device (SQUID) magnetometry was performed on two samples of melt-spun and optimally annealed Nd2Fe14B; one sample contained 2.3 wt % Nb and one was Nb-free. Continuous full hysteresis loops were measured with a SQUID magnetometer at T = 630 K, above the Curie temperature of the 2-14-1 phase, as a function of field (1 T less than or equal to H less than or equal to -1 T) and time on powdered samples sealed in quartz tubes at a vacuum of 10(-6) Torr. The measured hysteresis signals were deconstructed into a high-field linear paramagnetic portion and a low-field ferromagnetic signal of unclear origin. While the saturation magnetization of the ferromagnetic signal from both samples grows with time, the signal from the Nb-containing sample is always smaller. The coercivity data are consistent with a constant impurity particle size in the Nb-containing sample and an increasing impurity particle size in the Nb-free sample. The paramagnetic susceptibility signal from the Nd2Fe14B-type phase in the Nb-free sample increases with time, while that from the Nb-containing sample remains constant. It is suggested that the presence of Nb actively suppresses the thermally induced formation of poorly crystallized Fe-rich regions that apparently exist in samples of both compositions. (C) 1999 American Institute of Physics. [S0021-8979(99)47808-9]. C1 Brookhaven Natl Lab, Div Mat Sci, Dept Appl Sci, Upton, NY 11973 USA. Magnequench Int Inc, Anderson, IN 46013 USA. RP Lewis, LH (reprint author), Brookhaven Natl Lab, Div Mat Sci, Dept Appl Sci, Upton, NY 11973 USA. NR 11 TC 6 Z9 6 U1 1 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 APR 15 PY 1999 VL 85 IS 8 BP 5926 EP 5928 DI 10.1063/1.369916 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500210 ER PT J AU Nielsen, B Lewis, LH Friessnegg, T Ghosh, VJ Kramer, MJ McCallum, RW Dennis, K AF Nielsen, B Lewis, LH Friessnegg, T Ghosh, VJ Kramer, MJ McCallum, RW Dennis, K TI Atomic structure of the amorphous state of TiC-modified Nd2Fe14B as revealed by positron annihilation spectroscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID SI; DEFECTS AB Positron annihilation spectroscopy utilizing the Doppler broadening of the annihilation radiation (DBAR) method was performed on stoichiometric Nd2Fe14B ribbons containing 0, 2, and 6 wt % Ti-C that were melt spun to the x-ray amorphous state at a wheel speed of 40 m/s. DBAR data indicate that the as-spun samples are very homogeneous. It is found that an increase in the concentration of alloying additions promotes an increase in the shape parameter ("S parameter") of the symmetric Doppler-broadened positron-electron annihilation peak. This increase in the S parameter may be interpreted as an increase in the amount of open volume in the quenched glass. The presence of increased open volume is concurrent with an increased stability of the glass against crystallization. However, at the present time it is not clear if the increased thermal stability is a direct product of the increased open volume, or if stereochemical considerations determine the stability of the glass. (C) 1999 American Institute of Physics. [S0021-8979(99)47908-3]. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Sci Mat, Upton, NY 11973 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Nielsen, B (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Sci Mat, Upton, NY 11973 USA. RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 9 TC 3 Z9 3 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 APR 15 PY 1999 VL 85 IS 8 BP 5929 EP 5931 DI 10.1063/1.369917 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500211 ER PT J AU Yokoi, H Tozer, SW Kim, Y Rickel, D Kakudate, Y Usuba, S Fujiwara, S Takeyama, S Karczewski, G Wojtowicz, T Kossut, J AF Yokoi, H Tozer, SW Kim, Y Rickel, D Kakudate, Y Usuba, S Fujiwara, S Takeyama, S Karczewski, G Wojtowicz, T Kossut, J TI Pressure effect on magneto-optical properties in CdTe/(Cd,Mn)Te single quantum wells with high Mn concentration SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FL SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID FIELD; TRANSITION; CD1-XMNXTE; (CD,MN)TE AB The pressure effect on the magnetic field induced type I-type II transition is studied in a CdTe/Cd1-xMnxTe (x = 0.24) single quantum well. Photoluminescence measurements under hydrostatic pressures up to 1.07 GPa and long pulsed magnetic fields up to 60 T with a pulse duration of 2 s are reported. The pressures were generated in a plastic diamond anvil cell. A bend toward lower energies (additional red shift) is observed above 28.5 T in magnetic field dependence of the exciton energy for a 13 Angstrom thick quantum well. We attribute this red shift to a phenomenon preceding the type I-type II transition after a comparison with a simple quantum mechanical calculation. The onset field of the additional red shift increases by 3.4 T by applying a pressure of 1.07 GPa. Spin-spin coupling between the exciton and the Mn ion in the interface region is also investigated and found to be enhanced by pressure. (C) 1999 American Institute of Physics. [S0021-8979(99)43008-7]. C1 Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan. Himeji Inst Technol, Fac Sci, Kamigori, Hyogo 6781297, Japan. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. RP Natl Inst Mat & Chem Res, 1-1 Higashi, Tsukuba, Ibaraki 3058565, Japan. EM yokoi@nimc.go.jp RI Kossut, Jacek/K-9481-2016; Wojtowicz, Tomasz/A-2887-2017 OI Kossut, Jacek/0000-0001-6165-3169; NR 11 TC 15 Z9 16 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5935 EP 5937 DI 10.1063/1.369996 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500213 ER PT J AU Goremychkin, EA Osborn, R Sashin, IL AF Goremychkin, EA Osborn, R Sashin, IL TI Crystal field in the heavy fermion compound CeAl3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID SYSTEMS AB We present the results of an analysis of inelastic neutron scattering data on CeAl3. By combining the neutron scattering results with measurements of the single-crystal magnetic susceptibility, we have obtained an unambiguous set of crystal field parameters in CeAl3. A comparison of the crystal field parameters along the RAl3 (R=Ce, Pr, and Nd) series of isostructural compounds shows that in CeAl3, A(2)(0)< r(2)> is an order of magnitude larger, and A(4)(0)< r(4)> is three times larger, than in PrAl3 and NdAl3. These increases cannot be explained by changes in lattice parameters but are more likely to result from the enhancement of the hybridization of the cerium 4f electrons with the conduction electrons in CeAl3. This conclusion is in agreement with the results of our study of the RCu2Si2 series. (C) 1999 American Institute of Physics. [S0021-8979(99)55308-5]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Joint Inst Nucl Res, Frank Lab Neutron Phys, Dubna 141980, Moscow Region, Russia. RP Goremychkin, EA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011 OI Osborn, Raymond/0000-0001-9565-3140 NR 18 TC 11 Z9 11 U1 1 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 APR 15 PY 1999 VL 85 IS 8 BP 6046 EP 6048 DI 10.1063/1.369077 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500250 ER PT J AU Hong, KM Yang, FY Liu, K Reich, DH Searson, PC Chien, CL Balakirev, FF Boebinger, GS AF Hong, KM Yang, FY Liu, K Reich, DH Searson, PC Chien, CL Balakirev, FF Boebinger, GS TI Giant positive magnetoresistance of Bi nanowire arrays in high magnetic fields SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID BISMUTH; FILMS AB We have studied the magnetoresistance of electrodeposited Bi wires with diameters between 200 nm and 2 mu m in magnetic fields up to B = 55 T. In zero field, the resistance increases with decreasing temperature, indicating that the mean free path is strongly influenced by the nanowire geometry. The high-field magnetoresistance shows strong dependence on field orientation; typically 200% for B parallel to the wires, and 600%-800% for B perpendicular to the wires. The perpendicular magnetoresistance is well described by a modified two-current model which suggests that the high-field response of the arrays is fairly insensitive to the wire diameter, and is dominated by bulk properties of Bi. (C) 1999 American Institute of Physics. [S0021-8979(99)69908-X]. C1 Johns Hopkins Univ, Baltimore, MD 21218 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hong, KM (reprint author), Johns Hopkins Univ, Baltimore, MD 21218 USA. RI Searson, Peter /A-3311-2010; Liu, Kai/B-1163-2008; OI Liu, Kai/0000-0001-9413-6782; Searson, Peter/0000-0002-5417-0828 NR 12 TC 52 Z9 56 U1 2 U2 14 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 APR 15 PY 1999 VL 85 IS 8 BP 6184 EP 6186 DI 10.1063/1.370215 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500296 ER PT J AU Caciuffo, R Griveau, JC Kolberg, D Wastin, F Rinaldi, D Panchula, A Canfield, PC AF Caciuffo, R Griveau, JC Kolberg, D Wastin, F Rinaldi, D Panchula, A Canfield, PC TI Static and dynamic magnetic response of CeFe2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID DEPENDENT AC-SUSCEPTIBILITY; INTERMETALLIC COMPOUNDS; CE(FE1-XALX)2; SUBSTITUTIONS; SCATTERING; BEHAVIOR; NEUTRON; RU AB The magnetic response of CeFe2 single crystals was studied by direct-current magnetization and linear and nonlinear alternating-current susceptibility measurements. Several anomalies have been observed below the Curie temperature (T-C=228 K). A kink near 30 K in the real component of the linear susceptibility, chi'(1)(T), is accompanied by a frequency dependent peak in both the linear imaginary part, chi "(1)( T), and the third-harmonic nonlinear susceptibility, \(3/4)chi(3)H(0)(2)\. It is suggested that these features are related to the development of antiferromagnetic spin fluctuations of growing spatial extension, indicating an electronic instability below 80 K. (C) 1999 American Institute of Physics. [S0021-8979(99)73408-0]. C1 Univ Ancona, Dipartimento Sci Mat & Terra, Ist Nazl Fis Mat, I-60131 Ancona, Italy. Commiss European Communities, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, Germany. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Caciuffo, R (reprint author), Univ Ancona, Dipartimento Sci Mat & Terra, Ist Nazl Fis Mat, Via Brecce Bianche, I-60131 Ancona, Italy. EM rgc@popcsi.unian.it RI Canfield, Paul/H-2698-2014; OI Caciuffo, Roberto G. M./0000-0002-8708-6219 NR 15 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 6229 EP 6231 DI 10.1063/1.370230 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500311 ER PT J AU Kedziora, GS Pople, JA Rassolov, VA Ratner, MA Redfern, PC Curtiss, LA AF Kedziora, GS Pople, JA Rassolov, VA Ratner, MA Redfern, PC Curtiss, LA TI The relativistic Dirac-Coulomb-Fock effect on atomization energies SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIRECT PERTURBATION-THEORY; DENSITY-FUNCTIONAL THEORIES; MOLECULAR-PROPERTIES; 2ND-ROW COMPOUNDS; GAUSSIAN-1 THEORY; COMPUTATION; SIH4; SET AB We have used a second-order perturbation treatment of the Dirac-Coulomb-Hartree-Fock method to estimate relativistic contributions to energies in the G2/97 test set. The one-electron relativistic effect on atomization energies of molecules containing first-and second-row atoms nearly always reduces binding. When the relativistic corrections are included in G3 theory and assessed on the G2/97 test set, there is little change in overall performance. (C) 1999 American Institute of Physics. [S0021-9606(99)30815-1]. C1 Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Kedziora, GS (reprint author), Northwestern Univ, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA. OI Rassolov, Vitaly/0000-0002-7244-8870 NR 27 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1999 VL 110 IS 15 BP 7123 EP 7126 DI 10.1063/1.478615 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184QZ UT WOS:000079625600002 ER PT J AU Chen, Z Strauss, HL Loong, CK AF Chen, Z Strauss, HL Loong, CK TI The interaction of H-2 with water ice by neutron scattering: Rotation and translation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RAMAN-SPECTRUM; HIGH-PRESSURES; HYDROGEN; DYNAMICS AB The inelastic neutron scattering from H-2 in D2O ice at energy transfers that correspond to rotation-translation are presented. Both the first energy gain and the energy loss peaks are observed. The position of the peaks shows that the H-2 molecules execute nearly free rotation. The translational (recoil) contribution to the band positions as well as their widths can be fit by free translation with the molecule having an effective mass of about 1.7 M-0 where M-0 is the mass of H-2. The experimental results are compared to the available computer simulations. (C) 1999 American Institute of Physics. [S0021-9606(99)50215-8]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Loong, CK (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Chen, Zhan/G-8312-2016 OI Chen, Zhan/0000-0001-8687-8348 NR 23 TC 6 Z9 6 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1999 VL 110 IS 15 BP 7354 EP 7358 DI 10.1063/1.478637 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184QZ UT WOS:000079625600029 ER PT J AU Zhang, ZJ Mitrinovic, DM Williams, SM Huang, ZQ Schlossman, ML AF Zhang, ZJ Mitrinovic, DM Williams, SM Huang, ZQ Schlossman, ML TI X-ray scattering from monolayers of F(CF2)(10)(CH2)(2)OH at the water-(hexane solution) and water-vapor interfaces SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PERFLUORO-N-EICOSANE; LIQUID-LIQUID INTERFACE; MOLECULAR-DYNAMICS; 2ND-HARMONIC GENERATION; AIR/WATER INTERFACE; LANGMUIR MONOLAYER; PHASE-TRANSITION; ADSORBED FILM; REFLECTIVITY; SURFACE AB Synchrotron x-ray reflectivity is used to study the structure of a monolayer of F(CF2)(10)(CH2)(2)OH self-assembled at the liquid-liquid interface from a solution in hexane placed in contact with water. It is demonstrated that this monolayer is in a high density (solid) phase below a transition temperature. This is in contrast to the conventional expectation that soluble surfactants form disordered monolayers at the liquid- liquid interface. Above the transition temperature the monolayer desorbs into the hexane solution, leaving behind an interface with a very low density of surfactants. Hysteresis in the formation of the monolayer occurs when the temperature is scanned through the transition temperature. The success of these measurements relied upon the development of a novel technique to flatten the liquid-liquid interface to the extent required for x-ray reflectivity. The measurements of F(CF2)(10)(CH2)(2)OH at the liquid-liquid interface are compared to x-ray surface diffraction measurements of monolayers of the same material spread at the water-vapor interface. A solid to disordered-phase phase transition also occurs in the spread monolayer though at a slightly higher temperature. This indicates that the hexane acts to disorder the solid monolayer at the water-hexane interface. A measurement of the thermal expansion coefficient of the monolayer at the water-vapor interface is consistent with literature values for bulk hydrocarbon rotator phases, in contrast with previous measurements on monolayers of perfluoro-n-eicosane supported on water. (C) 1999 American Institute of Physics. [S0021-9606(99)70615-X]. C1 Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. RP Schlossman, ML (reprint author), Univ Chicago, Dept Phys, 845 W Taylor St, Chicago, IL 60637 USA. EM schloss@uic.edu NR 54 TC 62 Z9 63 U1 0 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 APR 15 PY 1999 VL 110 IS 15 BP 7421 EP 7432 DI 10.1063/1.478644 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184QZ UT WOS:000079625600037 ER PT J AU Kendrick, BK Mead, CA Truhlar, DG AF Kendrick, BK Mead, CA Truhlar, DG TI Comment on "On the Longuet-Higgins phase and its relation to the electronic adiabatic-diabatic transformation angle" SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter ID CONICAL INTERSECTION; DERIVATIVE COUPLINGS; IDENTICAL NUCLEI; WAVE-FUNCTIONS; ENERGIES; STATES; EQUATION; VICINITY; SYSTEMS C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Univ Minnesota, Inst Supercomp, Minneapolis, MN 55455 USA. RP Kendrick, BK (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-12,MS-B268, Los Alamos, NM 87545 USA. RI Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 20 TC 22 Z9 22 U1 1 U2 12 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 APR 15 PY 1999 VL 110 IS 15 BP 7594 EP 7597 DI 10.1063/1.478670 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184QZ UT WOS:000079625600056 ER PT J AU Cooper, LW Cota, GF Pomeroy, LR Grebmeier, JM Whitledge, TE AF Cooper, LW Cota, GF Pomeroy, LR Grebmeier, JM Whitledge, TE TI Modification of NO, PO, and NO/PO during flow across the Bering and Chukchi shelves: Implications for use as Arctic water mass tracers SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID OCEAN; SEA; DENITRIFICATION; NUTRIENT; ATLANTIC; SUMMER; CIRCULATION; SEDIMENTS; PATTERNS; NITRATE AB The NO and PO tracers (9[NO3-] + O-2 and 135[PO4-] + O-2, respectively,) and their derivative NO/PO have found increasing use in Arctic water mass analyses for identifying the specific basin or shelf areas from which surface waters originate, based upon assumed differences in Pacific- and Atlantic-derived content and basin-to-basin differences within the Arctic. Following shipboard sampling in June-September 1993 and May-June 1994, both north and south of Bering Strait, we have found evidence that Pacific-derived waters flowing north to Bering Strait do not necessarily have any unique NO, PO, or NO/PO identity that would permit unequivocal use as a water mass tracer. In particular, NO/PO ratios in the Bering Sea continental shelf (<150 m) waters varied from 0.7 to 1.1, which encompasses ratios previously reported for Arctic continental shelf and Atlantic origin waters in the Arctic Ocean. The highest NO/PO ratios (similar to 1) in the Bering Sea were observed to the southwest of St. Lawrence Island, close to where high nutrient waters are first upwelled onto the shelf and seasonally early in the biological production cycle. By contrast, later in the summer, north of Bering Strait, at the depth of the Arctic Ocean nutrient maximum, the highest concentrations of silica (similar to 60 mu M) were associated with low NO/PO ratios (similar to 0.7). Apparent increases in the proportions of sea ice melt in these waters, inferred from O-18 and salinity regressions, were associated with lower NO/PO ratios. This pattern, the potential for sea-air exchange, and a significant relationship between decreases in nitrate/phosphate ratios and both NO/PO ratios and silica concentrations indicate that biological and physical processes north and south of Bering Strait affect the fidelity of these nutrient-based tracers. These results indicate the need for consideration of shelf-based processes before NO/PO ratios and other nutrient-based tracers can be successfully applied as Arctic circulation tracers. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA 23508 USA. Univ Tennessee, Dept Ecol & Evolut Biol, Knoxville, TN 37996 USA. Univ Georgia, Inst Ecol, Athens, GA 30602 USA. Univ Texas, Inst Marine Sci, Austin, TX 78712 USA. RP Cooper, LW (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008,MS6038, Oak Ridge, TN 37831 USA. RI Cooper, Lee/E-5251-2012; Grebmeier, Jacqueline/L-9805-2013 OI Cooper, Lee/0000-0001-7734-8388; Grebmeier, Jacqueline/0000-0001-7624-3568 NR 30 TC 32 Z9 33 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 1999 VL 104 IS C4 BP 7827 EP 7836 DI 10.1029/1999JC900010 PG 10 WC Oceanography SC Oceanography GA 187KA UT WOS:000079784700015 ER PT J AU Park, JW Pedraza, AJ Lowndes, DH AF Park, JW Pedraza, AJ Lowndes, DH TI The adhesion of copper films deposited onto aluminum nitride SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SPECTROSCOPY; SAPPHIRE AB Good adhesion between copper film and AIN substrate is obtained when the surface of AIN is laser-irradiated prior to copper film deposition and post deposition annealing is conducted. Surface chemistry of AIN substrates before and after laser irradiation and the interfacial reactions of copper film/AIN couples were studied with Auger Electron Spectroscopy (AES) to understand the adhesion mechanisms. The surface of as-received AIN substrates was covered with a thin sheath of Al2O3 Laser irradiation removed the surface Al2O3 layers, smoothened the surface, and decomposed AIN leaving metallic aluminum on the surface. The interfacial reactions in the copper film/AIN couple are affected by the amounts of oxygen and metallic aluminum available at the interface. The adhesion mechanism is the formation of a Cu-O-Al compound at the interface of copper film/AIN couple. Since copper does not react with AIN, laser induced decomposition of AIN seems to be the driving force for the formation of the compound. (C) 1999 Kluwer Academic Publishers. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Park, JW (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. NR 12 TC 3 Z9 3 U1 0 U2 0 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 APR 15 PY 1999 VL 34 IS 8 BP 1933 EP 1942 DI 10.1023/A:1004544200291 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 196LR UT WOS:000080310300029 ER PT J AU Parikh, AN Gillmor, SD Beers, JD Beardmore, KM Cutts, RW Swanson, BI AF Parikh, AN Gillmor, SD Beers, JD Beardmore, KM Cutts, RW Swanson, BI TI Characterization of chain molecular assemblies in long-chain, layered silver thiolates: A joint infrared spectroscopy and x-ray diffraction study SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID NONLINEAR-OPTICAL-MATERIALS; NORMAL-ALKANES; NONPLANAR CONFORMERS; VIBRATIONAL-SPECTRA; PHASE-TRANSITION; SOLID-STATE; SIEVE; PHOSPHONATES; DIMENSIONS; COMPLEXES AB The first direct characterization of structures of bi-molecular chain assemblies in a self-consistent series of pillared, layered organic-inorganic long-chain silver (n-alkane)thiolates, (AgS(CH2)(n)CH3; n = 5, 6, 9, 11, 15, and 17), is reported using the combined application of infrared transmission spectroscopy and powder X-ray diffraction. The structural attributes elucidated:include quantitative estimates of average chain orientation, chain conformation, chain-chain translational order, interpenetration of the contiguous layers, as well as void characteristics in the chain matrix. The evidence presented here establishes that the layered chain assemblies sandwiched between the inorganic Ag-S backbones in a double-layer arrangement are comprised of an ordered packing of all-trans-extended chains. The average chain in each assembly is oriented vertically away from the quasi-hexagonal Ag-S lattice, in a two-dimensional pseudo-monoclinic arrangement of domains of 60-70 translationally correlated chains. Small interpenetration between the contiguous layers leads to the formation of regularly spaced 1D channels or corridors. The three-dimensional network of 1D channels alternates between the chain layers. All the chain structural characteristics deduced here are, in good conformity with those implied in the model proposed earlier by Dance and co-workers. The present results, together with the previous X-ray analysis for comparable short-chain AgSRs, are used to propose a two-step, hierarchical self-assembly mechanism for the:formation of silver (n-alkyl) thiolates. It is proposed that the primary self-assembly process involves the organization of Ag+ and RS- species into puckered sheets of quasi-hexagonally symmetric 2D lattices, with the chain substituents extending on each side. The subsequent self-assembly of these 2D building blocks in the third dimension via complementary stacking appears to complete the formation of sandwiched bimolecular chain assemblies. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Parikh, AN (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 NR 68 TC 80 Z9 82 U1 2 U2 17 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 APR 15 PY 1999 VL 103 IS 15 BP 2850 EP 2861 DI 10.1021/jp983938b PG 12 WC Chemistry, Physical SC Chemistry GA 189YN UT WOS:000079934100004 ER PT J AU Chen, Z Ward, R Tian, Y Eppler, AS Shen, YR Somorjai, GA AF Chen, Z Ward, R Tian, Y Eppler, AS Shen, YR Somorjai, GA TI Surface composition of biopolymer blends Biospan-SP/Phenoxy and Biospan-F/Phenoxy observed with SFG, XPS, and contact angle goniometry SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID VIBRATIONAL SPECTROSCOPY; POLYMER AB The surface compositions of two biopolymer blends, Biospan-SP/Phenoxy (BSP/PHE) and Biospan-F/Phenoxy (BF/PHE), have been studied using sum frequency generation (SFG), X-ray photoemission spectroscopy (XPS), and contact angle goniometry. BSP and BF are polyurethanes capped with poly(dimethylsiloxane) (PDMS) and fluoroalkyl (-(-CF2-)(n)-) as end groups, respectively. With contact angle goniometry, the surface tensions of pure BSP, BF, and PHE were found to be 26, 16, and 45 dyne/cm. For each of the blends, the polymer component with a lower;surface tension (BSP or BF, not PHE) tends to segregate to the surface. Our SFG experiment shows that the surface concentration of the surface-active component increases sharply as its bulk concentration increases. For BSP/PHE land BF/PHE) in air, the surface of the polymer blend is fully covered by BSP land BF) at a bulk concentration of 3.5 wt % (and 1 wt %). The contact angle measurements and the XPS studies yield compatible results. Comparison of results for BSP/PHE, BS/PHE (published before(1)), and BF/PHE polymer blends shows that the lower the surface energy of the surface-active component (surface tension: BF < BS ( BSP), the easier it is for the component to segregate to the surface (the minimum bulk concentration to saturate the surface is BF (1 wt %) < BS (1.7 wt %) < BSP (3.5 wt %)). After exposure to water, SFG spectra indicate that the surface layer of a polymer blend could be restructured. For BSP (3.5 wt %)/PHE, the hydrophobic end groups of BSP submerge while the hydrophilic polyurethane backbone emerges. For BF (1 wt %)/PHE, PHE emerges at the surface after exposure to water, but for BF (5 wt %)/PHE, the BF component dominates the surface in both air and water. Our results demonstrate the bifunctionality of polymer blends and show that the surface chemistry of polymer blends may be dominated by a minor component, while the mechanical stability of the polymer is controlled by the major component. C1 Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Polymer Technol Grp Inc, Berkeley, CA 94710 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Chen, Zhan/G-8312-2016 OI Chen, Zhan/0000-0001-8687-8348 NR 20 TC 38 Z9 39 U1 0 U2 11 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 APR 15 PY 1999 VL 103 IS 15 BP 2935 EP 2942 DI 10.1021/jp984502z PG 8 WC Chemistry, Physical SC Chemistry GA 189YN UT WOS:000079934100016 ER PT J AU Enquist, BJ Brown, JH West, GB AF Enquist, BJ Brown, JH West, GB TI Plant energetics and population density - Reply SO NATURE LA English DT Letter C1 Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA. Santa Fe Inst, Santa Fe, NM 87501 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Enquist, BJ (reprint author), Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA. NR 11 TC 10 Z9 11 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 15 PY 1999 VL 398 IS 6728 BP 573 EP 573 DI 10.1038/19219 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 186WX UT WOS:000079754700040 ER PT J AU Boettcher, S AF Boettcher, S TI Optimizing partitions of percolating graphs SO PHYSICA A LA English DT Article; Proceedings Paper CT International Conference on Percolation and Disordered Systems - Theory and Applications CY JUL 14-17, 1998 CL UNIV GIESSEN, SCHLOSS RAUISCHHOLZHAUSEN, GIESSEN, GERMANY SP Deutsch Forsch Gemeinschaft, Minerva Ctr Mesoscopics HO UNIV GIESSEN, SCHLOSS RAUISCHHOLZHAUSEN DE optimization; graph partitioning; percolation; simulated annealing; extremal optimization; self-organized criticality ID OPTIMIZATION; CRITICALITY AB The partitioning of random graphs is investigated numerically using "simulated annealing" and "extremal optimization". While generally in an NP-hard problem, it is shown that 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 "simulated annealing" is found to diverge in the thermodynamic limit. On the other hand, "extremal optimization", a new general purpose method based on self-organized criticality, produces near-optimal partitions with bounded error at any low connectivity at a comparable computational cost. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, CNLS MS B258, Los Alamos, NM 87545 USA. Clark Atlanta Univ, Ctr Theoret Studies Phys Syst, Atlanta, GA 30314 USA. RP Boettcher, S (reprint author), Univ Calif Los Alamos Natl Lab, CNLS MS B258, Los Alamos, NM 87545 USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 10 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD APR 15 PY 1999 VL 266 IS 1-4 BP 100 EP 103 DI 10.1016/S0378-4371(98)00582-2 PG 4 WC Physics, Multidisciplinary SC Physics GA 194AR UT WOS:000080170400018 ER PT J AU Boettcher, S AF Boettcher, S TI Life and times of an avalanche SO PHYSICA A LA English DT Article; Proceedings Paper CT International Conference on Percolation and Disordered Systems - Theory and Applications CY JUL 14-17, 1998 CL UNIV GIESSEN, SCHLOSS RAUISCHHOLZHAUSEN, GIESSEN, GERMANY SP Deutsch Forsch Gemeinschaft, Minerva Ctr Mesoscopics HO UNIV GIESSEN, SCHLOSS RAUISCHHOLZHAUSEN DE self-organized criticality; avalanches; aging; ultrametricity ID SELF-ORGANIZED CRITICALITY; PUNCTUATED EQUILIBRIUM; MODEL; DYNAMICS; EARTHQUAKES; EVOLUTION; PILE AB The avalanche dynamics in the Bak-Sneppen mechanism of self-organized criticality (SOC) is discussed. Rigorous arguments reveal the emergent history dependence that dominates the intermittent activity. In numerical studies the emergent SOC state shows glassy features, such as aging and an ultrametric organization of activity. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Clark Atlanta Univ, Ctr Theoret Studies Phys Syst, Atlanta, GA 30314 USA. RP Boettcher, S (reprint author), Univ Calif Los Alamos Natl Lab, CNLS, MS-B258, Los Alamos, NM 87545 USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 21 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD APR 15 PY 1999 VL 266 IS 1-4 BP 330 EP 333 DI 10.1016/S0378-4371(98)00610-4 PG 4 WC Physics, Multidisciplinary SC Physics GA 194AR UT WOS:000080170400047 ER PT J AU Jellison, GE Ramey, JO Boatner, AA AF Jellison, GE Ramey, JO Boatner, AA TI Optical functions of BiI3 as measured by generalized ellipsometry SO PHYSICAL REVIEW B LA English DT Article ID IODIDE SINGLE-CRYSTALS; EXCITONS AB The optical functions of BiI3 have been measured using two-modulator generalized ellipsomerry (2-MGE). The measurements were made on crystals grown by a vapor-transport method under conditions that produced relatively thick (similar to 1 mm) single crystals whose growth habits were characterized by the development of large faces for orientations other than that of the basal plane (i.e., other than the plane perpendicular to the c axis of the:BiI3 rhombohedral structure.) By performing 2-MGE measurements on crystal faces other than the basal plane, it is possible to determine both the ordinary and extraordinary dielectric functions of the material. While the ordinary dielectric functions have been determined from previous normal-incidence reflectivity measurements, to our knowledge the extraordinary dielectric functions obtained here using the 2-MGE method are new results. Both the ordinary and extraordinary band edges are the same energy (1.99 eV), and both exhibit? strong exciton. The matrix element for the ordinary transition, however, is a factor of 6 to 10 larger than the matrix element for the extraordinary transition near the band edge. [S0163-1829(99)03116-1]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Jellison, GE (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. OI Boatner, Lynn/0000-0002-0235-7594 NR 17 TC 32 Z9 32 U1 0 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1999 VL 59 IS 15 BP 9718 EP 9721 DI 10.1103/PhysRevB.59.9718 PG 4 WC Physics, Condensed Matter SC Physics GA 190JG UT WOS:000079958900009 ER PT J AU Raghavan, S Bishop, AR Kenkre, VM AF Raghavan, S Bishop, AR Kenkre, VM TI Quantum versus semiclassical description of self-trapping: Anharmonic effects SO PHYSICAL REVIEW B LA English DT Article ID NONLINEAR SCHRODINGER-EQUATION; PARTICLE-BOSON SYSTEMS; APPROXIMATION; DISSIPATION; SATURATION; STATES; DIMERS AB Self-trapping has been traditionally studied on the assumption that quasiparticles interact with harmonic phonons and that this interaction is linear in the displacement of the phonon. To complement recent semiclassical studies of anharmonicity and nonlinearity in this context, we present below a fully quantum-mechanical analysis of a two-site system, where the oscillator is described by a tunably anharmonic potential, with a square well with infinite walls and the harmonic potential as its extreme limits, and wherein the interaction is nonlinear in the oscillator displacement. Mle find that even highly anharmonic polarons behave similar to their harmonic counterparts in that self-trapping is preserved for long times in the limit of strong coupling, and that the polaronic tunneling time scale depends exponentially on the polaron binding energy. Further, in agreement, with earlier results related to harmonic polarons, the semiclassical approximation agrees with the full quantum result in the massive oscillator limit of small oscillator frequency and strong quasiparticle-oscillator coupling. [S0163-1829(99)02815-5]. C1 Int Ctr Theoret Phys, I-34100 Trieste, Italy. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Mexico, Ctr Adv Studies, Albuquerque, NM 87131 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. RP Raghavan, S (reprint author), Univ Rochester, Dept Phys & Astron, Rochester Theory Ctr Opt Sci & Engn, Rochester, NY 14627 USA. NR 16 TC 5 Z9 5 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 APR 15 PY 1999 VL 59 IS 15 BP 9929 EP 9932 DI 10.1103/PhysRevB.59.9929 PG 4 WC Physics, Condensed Matter SC Physics GA 190JG UT WOS:000079958900059 ER PT J AU Mattila, T Zunger, A AF Mattila, T Zunger, A TI P-P and As-As isovalent impurity pairs in GaN: Interaction of deep t(2) levels SO PHYSICAL REVIEW B LA English DT Article ID PSEUDOPOTENTIALS; SEMICONDUCTORS; FORMALISM; DEFECTS; SILICON; ALLOYS; ENERGY; GAASN AB The electronic and atomic structure of substitutional nth neighbor (1 less than or equal to n less than or equal to 6) P-P and As-As impurity pairs in zinc blende GaN is investigated using self-consistent plane-wave pseudopotential and empirical pseudopotential methods. A single impurity introduces a deep t(2) gap level; we show that the interaction between the t(2) defect orbitals of the impurity pairs leads to pin interesting pattern of single-particle level splitting, being largest for the first (n = 1) and fourth (n = 4) neighbor pairs, both exhibiting a C-2v symmetry. The total energy of the nth order pair Delta E-(n) relative to isolated (n-->infinity) impurities indicates pairing tendency for n = 1 and n = 2 (Delta E-(1,E-2)<0) while n = 4 pairs are unstable (Delta E-(4)>0). We explain this behavior of Delta E-(n) vs n as a consequence of the interplay between two effects: an "elastic contribution" representing the interaction be tween the elastic strain fields of the two impurities and an "electronic contribution" describing the interaction of the defect orbitals of the two impurity atoms. The binding energies of the impurity-pair bound excitons are calculated for the n = 1 As-As and P-P pairs and are found to be significantly larger than for the corresponding isolated impurities. The probabilities for electronic transitions between the defect levels and conduction band are calculated. The results predict existence of a rich series of spectroscopic features distinct from single impurities. [S0163-1829(99)14415-1]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Mattila, T (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 32 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 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1999 VL 59 IS 15 BP 9943 EP 9953 DI 10.1103/PhysRevB.59.9943 PG 11 WC Physics, Condensed Matter SC Physics GA 190JG UT WOS:000079958900061 ER PT J AU Ciftja, O AF Ciftja, O TI Effective hypernetted-chain study of even-denominator-filling state of the fractional quantum Hall effect SO PHYSICAL REVIEW B LA English DT Article ID FILLED LANDAU-LEVEL; FLUID AB The microscopic approach for studying the half-filled state of the fractional quantum Hall effect is based on the idea of proposing a trial Fermi wave function of the Jastrow-Slater form, which is then fully projected onto the lowest Landau level. A simplified starting point is to drop the projection operator and to consider an unprojected wave function. A recent study claims that such a wave function approximated in a Jastrow form may still constitute a good starting point on the study of the half-filled state. In this paper we formalize the effective hypernetted-chain approximation and apply it to the unprojected Fermi wave function, which describes the even-denominator-filling states. We test the above approximation by using the Fermi hypernetted-chain theory, which constitutes the natural choice for the present case. Our results suggest that the approximation of the Slater determinant of plane waves as a Jastrow wave function may not be a very accurate approximation. We conclude that the lowest Landau-level projection operator cannot be neglected if one wants a better quantitative understanding of the phenomena. [S0163-1829(99)01416-2]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Ciftja, O (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 25 TC 12 Z9 12 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 APR 15 PY 1999 VL 59 IS 15 BP 10194 EP 10201 DI 10.1103/PhysRevB.59.10194 PG 8 WC Physics, Condensed Matter SC Physics GA 190JG UT WOS:000079958900094 ER PT J AU Pan, W Tsui, DC Draper, BL AF Pan, W Tsui, DC Draper, BL TI Mass enhancement of two-dimensional electrons in thin-oxide Si-MOSFET's SO PHYSICAL REVIEW B LA English DT Article ID TRANSPORT; SYSTEMS AB We wish to report in this paper a study of the effective mass (m*) in thin-oxide Si-metal-oxide-semiconductor field-effect transistors, using the temperature dependence of the Shubnikov-de Haas (SdH) effect and following the methodology developed by J.L. Smith and P.J. Stiles, Phys. Rev. Lett. 29 102 (1972). We find that in the thin oxide limit, when the oxide thickness d(ox) is smaller than the average two-dimensional electron-electron separation r, m* is still enhanced and the enhancement can be described by m*/m(B) =0.815+0.23(r/d(ox)), where m(B)=0.195m(e) is the bulk electron mass, m(e) the free electron mass. At n(s)=6 x 10(11)cm(2), for example, m* similar or equal to 0.25m(e), an enhancement doubles that previously reported by Smith and Stiles. Our result shows that the interaction between electrons in the semiconductor and the neutralizing positive charges on the metallic gate electrode is important for mass enhancement. We also studied the magnetic-field orientation dependence of the SdH effect and deduced a value of 3.0+/-0.5 for the effective g factor in our thin oxide samples. [S0163-1829(99)15615-7]. C1 Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pan, W (reprint author), Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. NR 9 TC 24 Z9 24 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1999 VL 59 IS 15 BP 10208 EP 10211 DI 10.1103/PhysRevB.59.10208 PG 4 WC Physics, Condensed Matter SC Physics GA 190JG UT WOS:000079958900096 ER PT J AU Honold, MM Harrison, N Singleton, J Nam, MS Blundell, SJ Mielke, CH Kartsovnik, MV Kushch, ND AF Honold, MM Harrison, N Singleton, J Nam, MS Blundell, SJ Mielke, CH Kartsovnik, MV Kushch, ND TI Pulsed-magnetic-field measurements of Hall potential oscillations in alpha-(BEDT-TTF)(2)TlHg(SCN)(4) within the quantum Hall regime SO PHYSICAL REVIEW B LA English DT Article ID FERMI-SURFACE; ORGANIC METALS; EDGE STATES; ALPHA-(BEDT-TTF)(2)KHG(SCN)(4); CONDUCTORS; MAGNETOTRANSPORT; BREAKDOWN; PHASE; SALT AB Using a variant of the Corbino geometry in pulsed magnetic fields of up to 60 T, we have made direct measurements of the Hall potential in alpha-(BEDT-TTF)(2)TlHg(SCN)(4) within the quantum Hall regime. This method enables the in-plane components of the resistivity tensor, which are normally very difficult to measure, to be investigated and the nonlinear behavior of the sample's I-V characteristics to be studied. It is found that an increasing probability of magnetic breakdown at higher fields leads to a degradation of the quantum Hall effect. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87545 USA. Walther Meissner Inst Tieftemp Forsch, D-85748 Garching, Germany. Russian Acad Sci, Inst Chem Phys Res, Chernogolovka 142432, Russia. RP Honold, MM (reprint author), Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. RI Kartsovnik, Mark/E-3598-2013 OI Kartsovnik, Mark/0000-0002-3011-0169 NR 23 TC 13 Z9 13 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 APR 15 PY 1999 VL 59 IS 16 BP 10417 EP 10420 DI 10.1103/PhysRevB.59.R10417 PG 4 WC Physics, Condensed Matter SC Physics GA 193BE UT WOS:000080114800006 ER PT J AU Shore, HB Rose, JH AF Shore, HB Rose, JH TI Pseudojellium, ideal metals, and stabilized jellium SO PHYSICAL REVIEW B LA English DT Article ID STRUCTURELESS PSEUDOPOTENTIAL MODEL; UNIFORM ELECTRON-GAS; TRANSITION-METALS; SURFACE-PROPERTIES; FUCHS CALCULATION; ENERGY; CLUSTERS; VOIDS AB Two new electron gas models, introduced in the early 1990s, describe the energetics of metals better than the conventional electron gas, jellium. The first, the "ideal metal," was derived by starting with jellium at a specified density and requiring that no forces act on the positive background when the system is cleaved. The second, "stabilized jellium,'' was derived by starting with the pseudopotential model of metals, requiring that this model yield equilibrium at the specified average electron density and then averaging the potential seen by the electrons to obtain an equivalent electron gas. Even though these derivations are conceptually quite different, their results, the ideal metal and stabilized jellium models, are very nearly identical. We explain their great similarity by deriving both the ideal metal and stabilized jellium in a unified way from pseudojellium-a stabilized electron gas model derived in the middle 1980s that includes the average electron-ion interaction, while maintaining the uniform ground state and computational simplicity of jellium. This derivation explains the near identity of the ideal metal and stabilized jellium and allows us to: understand the small differences between them. [S0163-1829(99)00816-4]. C1 San Diego State Univ, Dept Phys, San Diego, CA 92182 USA. Iowa State Univ Sci & Technol, Dept Phys, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP San Diego State Univ, Dept Phys, San Diego, CA 92182 USA. EM hshore@quantum.sdsu.edu; jhrose@iastate.edu NR 39 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 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1999 VL 59 IS 16 BP 10485 EP 10492 DI 10.1103/PhysRevB.59.10485 PG 8 WC Physics, Condensed Matter SC Physics GA 193BE UT WOS:000080114800020 ER PT J AU Lessmann, A Brennan, S Munkholm, A Schuster, M Riechert, H Materlik, G AF Lessmann, A Brennan, S Munkholm, A Schuster, M Riechert, H Materlik, G TI X-ray standing-wave study of (AlAs)(m)(GaAs)(n) short-period superlattices SO PHYSICAL REVIEW B LA English DT Article ID DIFFRACTION; MULTILAYERS; SURFACE; GAAS; CRYSTAL; ALAS AB X-ray standing-waves (XSW) are used for an investigation of the structure of (AlAs)(m)(GaAs)(n) short-period superlattices (SL's). The XSW induced modulation of x-ray fluorescence from the Al, As, and Ga atoms and the total photoelectron yield are monitored around the 0th order SL satellite (AlAs)(GaAs)(004,0) and the GaAs(004) substrate Bragg reflection. From the specific shape of these modulations and the sample reflectivity, an atomic model about the interfaces is derived. This is accomplished by comparing the experimental data with dynamical calculations of x-ray wavefield distribution and reflectivity, which are based on the Takagi-Taupin equation. The fluorescence measurements at the 0th order SL satellite reveal a high crystalline order in the AlAs layers of the short-period SL, whereas in the GaAs layers, a fraction of the Ga and As atoms is not on the ideal lattice positions. From the analysis, a model of the atomic distribution along the [001] direction can be determined. This reveals that at each internal interface in the GaAs layers, two Ga atom planes are shifted by up to 0.035 nm and one As atom plane by 0.023 nm. At each interface, the shifts are directed towards the substrate. Ln addition, the XSW field at the GaAs(004) substrate reflection results in a moire or beating effect in the SL structure, which can be used to determine the information depth Lambda e of total electron-yield measurements in a more detailed approach. [S0163-1829(99)12715-2]. C1 Stanford Synchrotron Radiat Lab, SLAC, Menlo Park, CA 94025 USA. Siemens AG, Corp Technol, D-81739 Munich, Germany. DESY, HASYLAB, D-22603 Hamburg, Germany. RP Lessmann, A (reprint author), Rich Seifert & Co, Rontgenwerk, Branch Off, Mannerstr 36, D-80997 Munich, Germany. RI Riechert, Henning/G-4178-2016 NR 34 TC 5 Z9 5 U1 1 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 APR 15 PY 1999 VL 59 IS 16 BP 10801 EP 10810 DI 10.1103/PhysRevB.59.10801 PG 10 WC Physics, Condensed Matter SC Physics GA 193BE UT WOS:000080114800062 ER PT J AU Arkani-Hamed, N Dimopoulos, S Dvali, G AF Arkani-Hamed, N Dimopoulos, S Dvali, G TI Phenomenology, astrophysics, and cosmology of theories with submillimeter dimensions and TeV scale quantum gravity SO PHYSICAL REVIEW D LA English DT Article ID INVISIBLE AXION; SUPERSYMMETRY; UNIFICATION; SU(5) AB We recently proposed a solution to the hierarchy problem not relying on low-energy supersymmetry or technicolor. Instead, the problem is nullified by bringing quantum gravity down to the TeV scale. This is accomplished by the presence of n greater than or equal to 2 new dimensions of submillimeter size, with the SM fields localized on a 3-brane in the higher dimensional space. In this paper we systematically study the experimental viability of this scenario. Constraints arise both from strong quantum gravitational effects at the TeV scale, and more importantly from the production of massless higher dimensional gravitons with TeV suppressed couplings. Theories with n>2 are safe due mainly to the infrared softness of higher dimensional gravity. For n = 2, the six dimensional Planck scale must be pushed above similar to 30 TeV to avoid cooling SN 1987A and distortions of the diffuse photon background. Nevertheless, the particular implementation of our framework within type I string theory can evade all constraints, for any n greater than or equal to 2, with string scale m(s)similar to 1 TeV. We also explore novel phenomena resulting from the existence of new states propagating in the higher dimensional space. The Peccei-Quinn solution to the strong CP problem is revived with a weak scale axion in the bulk. Gauge fields in the bulk can mediate repulsive forces similar to 10(6)-10(8) times stronger than gravity at submillimeter distances, as well as help stabilize the proton. Higher-dimensional gravitons produced on our brane and captured on a different "fat" brane can provide a natural dark matter candidate. [S0556-2821(98)02224-3]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Abdus Salaam Int Ctr Theoret Phys, I-34100 Trieste, Italy. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 32 TC 1801 Z9 1808 U1 3 U2 24 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 APR 15 PY 1999 VL 59 IS 8 AR 086004 DI 10.1103/PhysRevD.59.086004 PG 21 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 186XE UT WOS:000079755500059 ER PT J AU Brisudova, MM AF Brisudova, MM TI Electromagnetic duality and light-front coordinates SO PHYSICAL REVIEW D LA English DT Article ID INFINITE-MOMENTUM; FIELD-THEORIES; NULL-PLANE; QCD; QUANTIZATION; DYNAMICS; MODEL AB We review the light-front Hamiltonian approach for the Abelian gauge theory in 3+1 dimensions, and then study electromagnetic duality in this framework. [S0556-2821(99)02608-9]. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Theoret, T-5, Los Alamos, NM 87545 USA. NR 34 TC 3 Z9 3 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 APR 15 PY 1999 VL 59 IS 8 AR 087702 DI 10.1103/PhysRevD.59.087702 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 186XE UT WOS:000079755500062 ER PT J AU Carman, DS Bland, LC Chant, NS Gu, T Huber, GM Huffman, J Klyachko, A Markham, BC Roos, PG Schwandt, P Solberg, K AF Carman, DS Bland, LC Chant, NS Gu, T Huber, GM Huffman, J Klyachko, A Markham, BC Roos, PG Schwandt, P Solberg, K TI Quasifree inclusive and exclusive cross sections at 200 MeV SO PHYSICS LETTERS B LA English DT Article DE quasifree scattering; impulse approximation; (p,p '); (p,n); (p,Np); collectivity ID POLARIZATION-TRANSFER; MEV PROTONS; E,E'P REACTION; NUCLEI; SCATTERING; DEPENDENCE; KNOCKOUT; REGION; C-12 AB Cross section measurements for both inclusive (p,p') and exclusive (p,2p) and (p,np) quasifree scattering at 200 MeV from H-2 and C-12 have been completed from 27 degrees to 34 degrees. Inter-comparisons of these inclusive and exclusive data are employed to determine the contribution of single-step NN scattering to the inclusive scattering yield. This determination is crucial to address whether the inclusive yield arises primarily from these simple hard scattering processes, as is tacitly assumed in most theoretical calculations of this process, or whether non-negligible contributions from more complicated reaction dynamics are present. These data are also employed to study the effect of the nuclear medium on the underlying NN interaction and to show that there is no strong evidence for collectivity in the nuclear response at 200 MeV. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Indiana Univ, Cyclotron Facil, Bloomington, IN 47408 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Regina, Regina, SK S4S 0A2, Canada. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. RP Carman, DS (reprint author), Thomas Jefferson Natl Accelerator Facil, Dept Phys, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 23 TC 5 Z9 5 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 APR 15 PY 1999 VL 452 IS 1-2 BP 8 EP 14 DI 10.1016/S0370-2693(99)00275-0 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 191RN UT WOS:000080035500002 ER PT J AU Abe, K Akagi, T Anthony, PL Antonov, R Arnold, RG Averett, T Band, HR Bauer, JM Borel, H Bosted, PE Breton, V Button-Shafer, J Chen, JP Chupp, TE Clendenin, J Comptour, C Coulter, KP Court, G Crabb, D Daoudi, M Day, D Dietrich, FS Dunne, J Dutz, H Erbacher, R Fellbaum, J Feltham, A Fonvieille, H Frlez, E Garvey, D Gearhart, R Gomez, J Grenier, P Griffioen, KA Hoibraten, S Hughes, EW Hyde-Wright, C Johnson, JR Kawall, D Klein, A Kuhn, SE Kuriki, M Lindgren, R Liu, TJ Lombard-Nelsen, RM Marroncle, J Maruyama, T Maruyama, XK McCarthy, J Meyer, W Meziani, ZE Minehart, R Mitchell, J Morgenstern, J Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Raines, P Raue, B Reyna, D Rijllart, A Roblin, Y Rochester, LS Rock, SE Rondon, OA Sick, I Smith, LC Smith, TB Spengos, M Staley, F Steiner, P St Lorant, S Stuart, LM Suekane, F Szalata, ZM Tang, H Terrien, Y Usher, T Walz, D Wesselmann, F White, JL Witte, K Young, CC Youngman, B Yuta, H Zapalac, G Zihlmann, B Zimmermann, D AF Abe, K Akagi, T Anthony, PL Antonov, R Arnold, RG Averett, T Band, HR Bauer, JM Borel, H Bosted, PE Breton, V Button-Shafer, J Chen, JP Chupp, TE Clendenin, J Comptour, C Coulter, KP Court, G Crabb, D Daoudi, M Day, D Dietrich, FS Dunne, J Dutz, H Erbacher, R Fellbaum, J Feltham, A Fonvieille, H Frlez, E Garvey, D Gearhart, R Gomez, J Grenier, P Griffioen, KA Hoibraten, S Hughes, EW Hyde-Wright, C Johnson, JR Kawall, D Klein, A Kuhn, SE Kuriki, M Lindgren, R Liu, TJ Lombard-Nelsen, RM Marroncle, J Maruyama, T Maruyama, XK McCarthy, J Meyer, W Meziani, ZE Minehart, R Mitchell, J Morgenstern, J Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Raines, P Raue, B Reyna, D Rijllart, A Roblin, Y Rochester, LS Rock, SE Rondon, OA Sick, I Smith, LC Smith, TB Spengos, M Staley, F Steiner, P St Lorant, S Stuart, LM Suekane, F Szalata, ZM Tang, H Terrien, Y Usher, T Walz, D Wesselmann, F White, JL Witte, K Young, CC Youngman, B Yuta, H Zapalac, G Zihlmann, B Zimmermann, D CA E143 Collaboration TI Measurements of R = sigma(L)/sigma(T) for 0.03 < x < 0.1 and fit to world data SO PHYSICS LETTERS B LA English DT Article ID INELASTIC ELECTRON-SCATTERING; PRECISION-MEASUREMENT; MUON SCATTERING; L/SIGMA-T; DEPENDENCE; PROTON AB Measurements were made at SLAG of the cross section for scattering 29 GeV electrons from carbon at a laboratory angle of 4.5 degrees, corresponding to 0.03 < x < 0.1 and 1.3 < Q(2) < 2.7 GeV2. Values of R = sigma(L)/sigma(T), were extracted in this kinematic range by comparing these data to cross sections measured at a higher beam energy by the NMC collaboration. The results are in reasonable agreement with pQCD calculations and with extrapolations of the R1990 parameterization of previous data. A new fit is made including these data and other recent results. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Tohoku Univ, Sendai, Miyagi 980, Japan. American Univ, Washington, DC 20016 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Univ Blaise Pascal, CNRS, LPC IN2P3, F-63170 Aubiere, France. CEA Saclay, SPhN, DAPNIA, F-91191 Gif Sur Yvette, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Michigan, Ann Arbor, MI 48109 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Univ Penn, Philadelphia, PA 19104 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Stanford, CA 94305 USA. Temple Univ, Philadelphia, PA 19122 USA. Thomas Jefferson Nat 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 Abe, K (reprint author), Tohoku Univ, Sendai, Miyagi 980, Japan. RI Averett, Todd/A-2969-2011; Rondon Aramayo, Oscar/B-5880-2013; Frlez, Emil/B-6487-2013; Day, Donal/C-5020-2015; OI Day, Donal/0000-0001-7126-8934; Wesselmann, Frank/0000-0001-7834-7977 NR 22 TC 120 Z9 121 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 APR 15 PY 1999 VL 452 IS 1-2 BP 194 EP 200 DI 10.1016/S0370-2693(99)00244-0 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 191RN UT WOS:000080035500029 ER PT J AU Bewley, MC Jeffrey, PD Patchett, ML Kanyo, ZF Baker, EN AF Bewley, MC Jeffrey, PD Patchett, ML Kanyo, ZF Baker, EN TI Crystal structures of Bacillus caldovelox arginase in complex with substrate and inhibitors reveal new insights into activation, inhibition and catalysis in the arginase superfamily SO STRUCTURE WITH FOLDING & DESIGN LA English DT Article DE arginine hydrolysis; catalytic mechanism; crystal structure; ligand binding; manganese enzyme; nitrogen metabolism ID BINUCLEAR MANGANESE CLUSTER; RAT-LIVER ARGINASE; PROTEIN STRUCTURES; ORNITHINE CARBAMOYLTRANSFERASE; L-ARGININE; PROGRAM; ENZYMES AB Background: Arginase is a manganese-dependent enzyme that catalyzes the hydrolysis of L-arginine to L-ornithine and urea. In ureotelic animals arginase is the final enzyme of the urea cycle, but in many species it has a wider role controlling the use of arginine for other metabolic purposes, including the production of creatine, polyamines, proline and nitric oxide. Arginase activity is regulated by various small molecules, including the product L-ornithine. The aim of these structural studies was to test aspects of the catalytic mechanism and to investigate the structural basis of arginase inhibition. Results: We report here the crystal structures of arginase from Bacillus caldovelox at pH 5.6 and pH 8.5, and of binary complexes of the enzyme with L-arginine, L-ornithine and L-lysine at pH 8.5. The arginase monomer comprises a single compact alpha/beta domain that further associates into a hexameric quaternary structure. The binary complexes reveal a common mode of ligand binding, which places the substrate adjacent to the dimanganese centre. We also observe a conformational change that impacts on the active site and is coupled with the occupancy of an external site by guanidine or arginine. Conclusions: The structures reported here clarify aspects of the active site and indicate key features of the catalytic mechanism, including substrate coordination to one of the manganese ions and an orientational role for a neighboring histidine residue. Stereospecificity for L-amino acids is found to depend on their precise recognition at the active-site rim. Identification of a second arginine-binding site, remote from the active site, and associated conformational changes lead us to propose a regulatory role for this site in substrate hydrolysis. C1 Massey Univ, Dept Biochem, Palmerston North, New Zealand. Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RP Bewley, MC (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 37 TC 96 Z9 100 U1 3 U2 11 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0969-2126 J9 STRUCT FOLD DES JI Struct. Fold. Des. PD APR 15 PY 1999 VL 7 IS 4 BP 435 EP 448 DI 10.1016/S0969-2126(99)80056-2 PG 14 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 188PR UT WOS:000079857600011 PM 10196128 ER PT J AU Guo, XZ Khakoo, MA Mathews, DF Mikaelian, G Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ AF Guo, XZ Khakoo, MA Mathews, DF Mikaelian, G Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ TI Differential cross section ratios for low-energy electron-impact excitation of the 4p(5)5s levels of krypton - sensitive tests of relativistic effects for heavy noble gases SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID CLOSE-COUPLING CALCULATIONS; NEAR-THRESHOLD; R-MATRIX; SPIN-ORBIT; SCATTERING; STATES; KR; XE; HELIUM; ATOMS AB We present new experimental measurements and theoretical calculations of R-matrix and unitarized first-order many-body theory for electron-impact excitation of krypton. The usefulness of differential cross section ratios in providing sensitive tests of electron scattering models for the excitation of the np(5)(n + 1)s configuration of the heavy rare gases is demonstrated. In addition to differential cross sections alone, these ratios provide interesting physical insights into the details of the collision process. Comparisons of the measured ratios with predictions from the present and other available calculations show some agreement, but also reveal that significant improvements of these models are required. C1 Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Nottingham, Dept Math, Nottingham NG7 2RD, England. Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Univ Newcastle Upon Tyne, Dept Phys, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. RP Guo, XZ (reprint author), Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. RI Bartschat, Klaus/I-2527-2012 NR 28 TC 12 Z9 12 U1 0 U2 2 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 APR 14 PY 1999 VL 32 IS 7 BP L155 EP L163 DI 10.1088/0953-4075/32/7/002 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 189PN UT WOS:000079913900002 ER PT J AU Albright, JG Annunziata, O Miller, DG Paduano, L Pearlstein, AJ AF Albright, JG Annunziata, O Miller, DG Paduano, L Pearlstein, AJ TI Precision measurements of binary and multicomponent diffusion coefficients in protein solutions relevant to crystal growth: Lysozyme chloride in water and aqueous NaCl at pH 4.5 and 25 degrees C-perpendicular to SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article; Proceedings Paper CT 7th International Conference on Crystallization of Biological Macromolecules CY MAY 03-08, 1998 CL GRANADA, SPAIN ID EGG-WHITE LYSOZYME; LIGHT-SCATTERING; CONCENTRATION RATIO; ROTATIONAL DIFFUSION; SELF-DIFFUSION; SERUM-ALBUMIN; 25-DEGREES-C; NACL-MGCL2-H2O; SYSTEM; CRYSTALLIZATION AB Accurate models of protein diffusion are important in a number of applications, including liquid-liquid phase separation and growth of protein crystals for X-ray diffraction studies. In concentrated multicomponent protein systems, significant deviations from pseudobinary behavior can be expected. Rayleigh interferometry is used to measure the four elements (D-ij)(v) of the ternary diffusion coefficient matrix for the extensively investigated protein, hen egg-white lysozyme (component I) in aqueous NaCl (component 2) at pH 4.5 and 25 degrees C. These are the first multicomponent diffusion coefficients measured for any protein system at concentrations high enough to be relevant to modeling and prediction of crystal growth or other phase transitions, and the first for a system involving lysozyme at any concentration. The four ternary diffusion coefficients for the system lysozyme chloride/NaCl/water are reported for lysozyme chloride at 0.60 mM (8.6 mg/mL) and NaCl at concentrations of 0.25, 0.50, 0.65, 0.90, and 1.30 M (1.4, 2.8, 3.7, 5.1, and 7.2 wt %), with the latter two compositions being supersaturated. One cross-term, (D-21)(v), is 80-259 times larger than the main term (D-11)(v) and 7-18 times larger than (D-22)(v) Standard interferometric diagnostic tests indicate that aggregation is unimportant in our experiments. We also present binary diffusion coefficients D-v for lysozyme chloride/water at concentrations from 0.43 to 3.08 mM (6.2-44.1 mg/mL), at the same pH and temperature. The precision of the results is about 0.1% for the binary diffusion coefficients and diagonal ternary diffusion coefficients, and about 1-2% for the cross-terms. For the ternary systems investigated, we show that a single pseudobinary diffusion coefficient does not accurately describe diffusive transport, and predictions by simple models such as the Nernst-Hartley equations are inaccurate at the higher concentrations considered here. Finally, dynamic light-scattering diffusion coefficients, differing from both our interferometrically measured (D-ij)(v) and a theoretical prediction of light-scattering diffusion coefficients in multicomponent systems, are reported for the same solutions used for the ternary experiments at 1.30 M. C1 Texas Christian Univ, Dept Chem, Ft Worth, TX 76129 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Univ Naples, Dipartimento Chim, I-80134 Naples, Italy. RP Albright, JG (reprint author), Texas Christian Univ, Dept Chem, Ft Worth, TX 76129 USA. OI PADUANO, Luigi/0000-0002-1105-4237 NR 75 TC 76 Z9 76 U1 1 U2 16 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 APR 14 PY 1999 VL 121 IS 14 BP 3256 EP 3266 DI 10.1021/ja9834834 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 189BT UT WOS:000079884800002 ER PT J AU Christe, KO Wilson, WW Dixon, DA Boatz, JA AF Christe, KO Wilson, WW Dixon, DA Boatz, JA TI Hetpacoordination. Synthesis and characterization of the IOF52- dianion, an XOF5E species SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID VIBRATIONAL-SPECTRA; 1ST EXAMPLE; ANION; XEOF5 AB The new IOF52- dianion was prepared in the form of its cesium salt by heating stoichiometric amounts of CsF, I2O5, and IFS to 162 degrees C for 14 days. The white stable solid was characterized by vibrational spectroscopy. A normal coordinate analysis was carried out with the help of ab initio calculations at the HF/ECP/DZP level of theory and resulted in an excellent agreement between observed and calculated frequencies. The structure of IOF52- iS that of a pentagonal bipyramid with five equatorial fluorine ligands, and an oxygen atom and one sterically active free valence electron pair occupying the two axial positions. The structure is very similar to that previously established by vibrational spectroscopy and X-ray diffraction for isoelectronic XeOF5- and represents only the second example of a heptacoordinated XOF5E (E = free valence electron pair) main group species. The possible existence of the IOF63- trianion is briefly discussed. C1 USAF, Res Lab, Edwards AFB, CA 93524 USA. Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Christe, KO (reprint author), USAF, Res Lab, Edwards AFB, CA 93524 USA. RI Christe, Karl/O-4885-2014 OI Christe, Karl/0000-0003-0661-5519 NR 32 TC 11 Z9 11 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 14 PY 1999 VL 121 IS 14 BP 3382 EP 3385 DI 10.1021/ja984248o PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA 189BT UT WOS:000079884800018 ER PT J AU Luhmer, M Goodson, BM Song, YQ Laws, DD Kaiser, L Cyrier, MC Pines, A AF Luhmer, M Goodson, BM Song, YQ Laws, DD Kaiser, L Cyrier, MC Pines, A TI Study of xenon binding in cryptophane-A using laser-induced NMR polarization enhancement SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; NOBLE-GAS; ALPHA-CYCLODEXTRIN; SURFACE NMR; HYPERPOLARIZED XE-129; SPIN RELAXATION; LIQUID XENON; MRI; PROTEINS; SPECTROSCOPY AB In solution, spin-polarization transfer between laser-polarized xenon and the hydrogen nuclei of nearby molecules leads to signal enhancements in the resolved H-1 NMR spectrum, offering new opportunities for probing the chemical environment of xenon atoms. Following binding of laser-polarized xenon to molecules of cryptophane-A, selective enhancements of the H-1 NMR signals were observed. A theoretical framework for the interpretation of such experimental results is provided, and the spin polarization-induced nuclear Overhauser effects are shown to yield information about the molecular environment of xenon. The observed selective H-1 enhancements allowed xenon-proton internuclear distances to be estimated. These distances reveal structural characteristics of the complex, including the preferred molecular conformations adopted by cryptophane-A upon binding of xenon. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Free Univ Brussels, Lab Chim Organ EP, B-1050 Brussels, Belgium. RP Pines, A (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. OI Goodson, Boyd/0000-0001-6079-5077 NR 64 TC 79 Z9 79 U1 1 U2 13 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 APR 14 PY 1999 VL 121 IS 14 BP 3502 EP 3512 DI 10.1021/ja9841916 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 189BT UT WOS:000079884800033 ER PT J AU Weis, P Kemper, PR Bowers, MT Xantheas, SS AF Weis, P Kemper, PR Bowers, MT Xantheas, SS TI A new determination of the fluoride ion-water bond energy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAS-PHASE; PHOTOELECTRON-SPECTROSCOPY; VIBRATIONAL SPECTROSCOPY; MICROSCOPIC SOLVATION; CLUSTERS; HYDRATION; HYDROGEN; ANIONS; H2O; CL C1 Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Bowers, MT (reprint author), Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. RI Xantheas, Sotiris/L-1239-2015 NR 30 TC 55 Z9 55 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 APR 14 PY 1999 VL 121 IS 14 BP 3531 EP 3532 DI 10.1021/ja9842161 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 189BT UT WOS:000079884800038 ER PT J AU Blanton, WB Gordon-Wylie, SW Clark, GR Jordan, KD Wood, JT Geiser, U Collins, TJ AF Blanton, WB Gordon-Wylie, SW Clark, GR Jordan, KD Wood, JT Geiser, U Collins, TJ TI Synthesis and crystallographic characterization of an octameric water complex, (H2O)(8) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SELF-CONSISTENT-FIELD; MOLECULAR-INTERACTIONS; VIBRATIONAL-SPECTRA; CLUSTERS (H2O)(N); AB-INITIO; SPECTROSCOPY; ENERGY; N=1-6 C1 Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA. Univ Auckland, Auckland, New Zealand. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Clark, GR (reprint author), Carnegie Mellon Univ, Dept Chem, 4400 5th Ave, Pittsburgh, PA 15213 USA. RI Collins, Terrence/A-9807-2017 OI Collins, Terrence/0000-0003-2611-9184 NR 26 TC 216 Z9 218 U1 3 U2 9 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 APR 14 PY 1999 VL 121 IS 14 BP 3551 EP 3552 DI 10.1021/ja982100z PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 189BT UT WOS:000079884800048 ER PT J AU Zhang, RG Evans, G Rotella, FJ Westbrook, EM Beno, D Huberman, E Joachimiak, A Collart, FR AF Zhang, RG Evans, G Rotella, FJ Westbrook, EM Beno, D Huberman, E Joachimiak, A Collart, FR TI Characteristics and crystal structure of bacterial inosine-5 '-monophosphate dehydrogenase SO BIOCHEMISTRY LA English DT Article ID INOSINE MONOPHOSPHATE DEHYDROGENASE; IMP DEHYDROGENASE; 5'-MONOPHOSPHATE DEHYDROGENASE; MYCOPHENOLIC-ACID; TRITRICHOMONAS-FETUS; EXPRESSION; BINDING; IDENTIFICATION; PURIFICATION; DIFFRACTION AB IMP dehydrogenase (IMPDH) is an essential enzyme that catalyzes the first step unique to GTP synthesis. To provide a basis for the evaluation of IMPDH inhibitors as antimicrobial agents, we have expressed and characterized IMPDH from the pathogenic bacterium Streptococcus pyogenes. Our results show that the biochemical and kinetic characteristics of S. pyogenes IMPDH are similar to other bacterial IMPDH enzymes. However, the lack of sensitivity to mycophenolic acid and the K-m for NAD (1180 mu M) exemplify some of the differences between the bacterial and mammalian IMPDH enzymes, making it an attractive target for antimicrobial agents. To evaluate the basis for these differences, we determined the crystal structure of the bacterial enzyme at 1.9 Angstrom with substrate bound in the catalytic site. The structure was determined using selenomethionine-substituted protein and multiwavelength anomalous (MAD) analysis of data obtained with synchrotron radiation from the undulator beamline (19ID) of the Structural Biology Center at Argonne's Advanced Photon Source. S. pyogenes IMPDH is a tetramer with its four subunits related by a crystallographic 4-fold axis. The protein is composed of two domains: a TIM barrel domain that embodies the catalytic framework and a cystathione beta-synthase (CBS) dimer domain of so far unknown function. Using information provided by sequence alignments and the crystal structure, we prepared several site-specific mutants to examine the role of various active site regions in catalysis. These variants implicate the active site flap as an essential catalytic element and indicate there are significant differences in the catalytic environment of bacterial and mammalian IMPDH enzymes. Comparison of the structure of bacterial IMPDH with the known partial structures from eukaryotic organisms will provide an explanation of their distinct properties and contribute to the design of specific bacterial IMPDH inhibitors. C1 Argonne Natl Lab, Ctr Mech Biol & Biotechnol, Argonne, IL 60439 USA. RP Collart, FR (reprint author), Argonne Natl Lab, Ctr Mech Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Evans, Gwyndaf/R-5524-2016; OI Evans, Gwyndaf/0000-0002-6079-2201; Collart, Frank/0000-0001-6942-4483 NR 36 TC 139 Z9 145 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 13 PY 1999 VL 38 IS 15 BP 4691 EP 4700 DI 10.1021/bi982858v PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 189QZ UT WOS:000079918200005 PM 10200156 ER PT J AU Stevens, MJ AF Stevens, MJ TI Thoughts on the Structure of alkylsilane monolayers SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; SOLID-LIQUID INTERFACE; FORCE-FIELD; MOLECULAR-DYNAMICS; SILICA SURFACES; OCTADECYLTRICHLOROSILANE; ORGANIZATION; PHASE; SIO2 AB Cross-polymerization in alkylsilane self-assembled monolayers (SAMs) has been thought to be an essential ingredient of their stability. For alkylsilane SAMS at full coverage, it is shown here that cross-polymerization cannot occur due to steric effects. Thus, to form dense, fully covered monolayers, cross-polymerization must be avoided. Such monolayers should be as stable as alkanethiol SAMs, which also do not cross-polymerize. The structure of the headgroup plays a limiting role in possible monolayer structures. Due to large steric hindrances, the dimethylmonochlorosilanes cannot cover a silica surface with a density equal to the density of surface hydroxyls. In contrast, the trichlorosilanes can achieve such densities. To satisfy the steric constraints, the aliphatic tails must form a herringbone structure. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Stevens, MJ (reprint author), Sandia Natl Labs, MS 1111, Albuquerque, NM 87185 USA. NR 29 TC 152 Z9 154 U1 1 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 13 PY 1999 VL 15 IS 8 BP 2773 EP 2778 DI 10.1021/la981064e PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 187FF UT WOS:000079775700027 ER PT J AU Burns, AR Houston, JE Carpick, RW Michalske, TA AF Burns, AR Houston, JE Carpick, RW Michalske, TA TI Molecular level friction as revealed with a novel scanning probe SO LANGMUIR LA English DT Article ID ATOMIC-FORCE MICROSCOPY; FIELD OPTICAL MICROSCOPES; SHEAR-FORCE; ORGANIC-SURFACES; DISTANCE CONTROL; ADHESION; SCALE; MONOLAYERS; FILMS; TIP AB Friction at the molecular level is examined with a novel scanning probe microscope that observes the onset of energy dissipation and adhesive forces simultaneously. Friction is monitored by measuring the damped:vibrational amplitude of an oscillating probe tip, analogous to shear-force feedback commonly used in near-field scanning optical microscopes. A mechanically stable interfacial force sensor is used to measure normal forces at the tip independently and decoupled from the lateral forces, allowing one to observe friction from the early stages of the purely adhesive tensile regime to the latter stage of repulsive compression. Measurements on model lubricant silane and alkanethiol self-assembled monolayers indicate that friction dramatically increases with the strength of adhesive interactions between the tip and the monolayers. These adhesive interactions occur over an appreciable (7 +/- 1 Angstrom) displacement range, suggesting tensile reorientation of the lubricant chains and subsequent energy losses due to collective chain motion as well as dissipative hydrogen-bond breaking. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Burns, AR (reprint author), Sandia Natl Labs, Surface & Interface Sci Dept, MS 1413, Albuquerque, NM 87185 USA. NR 46 TC 58 Z9 58 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 13 PY 1999 VL 15 IS 8 BP 2922 EP 2930 DI 10.1021/la981521r PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 187FF UT WOS:000079775700048 ER PT J AU McCutcheon, JP Agrawal, RK Philips, SM Grassucci, RA Gerchman, SE Clemons, WM Ramakrishnan, V Frank, J AF McCutcheon, JP Agrawal, RK Philips, SM Grassucci, RA Gerchman, SE Clemons, WM Ramakrishnan, V Frank, J TI Location of translational initiation factor IF3 on the small ribosomal subunit SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE cryoelectron microscopy; ribosome ID ESCHERICHIA-COLI RIBOSOME; TRANSFER-RNA; FACTOR-III; CRYOELECTRON MICROSCOPY; PROTEIN-SYNTHESIS; 3-DIMENSIONAL RECONSTRUCTION; CROSS-LINKING; P-SITE; 16S; BINDING AB The location of translational initiation factor IF3 bound to the 30S subunit of the Thermus thermophilus ribosome has been determined by cryoelectron microscopy, Both the 30S IF3 complex and control 30S subunit structures,were determined to 27-Angstrom resolution. The difference map calculated from the two reconstructions reveals three prominent lobes of positive density. The previously solved crystal structure of IF3 fits very well irate two of these lobes, whereas the third lobe probably arises from conformational changes induced in the 30S subunit as a result of IF3 binding. Our placement of IF3 on the 30S subunit allows an understanding in structural terms of the biochemical functions of this initiation factor, namely its ability to dissociate 70S ribosomes into 30S and 50S subunits and the preferential selection of initiator tRNA by IF3 during initiation. C1 Univ Utah, Sch Med, Dept Biochem, Salt Lake City, UT 84132 USA. SUNY Albany, Wadsworth Ctr, Albany, NY 12222 USA. SUNY Albany, Howard Hughes Med Inst, Albany, NY 12222 USA. SUNY Albany, Dept Biomed Sci, Albany, NY 12222 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Ramakrishnan, V (reprint author), Univ Utah, Sch Med, Dept Biochem, 50 N Med Dr, Salt Lake City, UT 84132 USA. RI Clemons, William/D-1026-2009; OI Ramakrishnan, V/0000-0002-4699-2194 FU NIGMS NIH HHS [F31 GM019384, R01 GM055440, R01GM 44973, R01GM 55440, R37 GM029169, R37GM 29169] NR 56 TC 98 Z9 100 U1 0 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 13 PY 1999 VL 96 IS 8 BP 4301 EP 4306 DI 10.1073/pnas.96.8.4301 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 187BP UT WOS:000079766500020 PM 10200257 ER PT J AU Norton, DP Park, C Budai, JD Pennycook, SJ Prouteau, C AF Norton, DP Park, C Budai, JD Pennycook, SJ Prouteau, C TI Plume-induced stress in pulsed-laser deposited CeO2 films SO APPLIED PHYSICS LETTERS LA English DT Article ID ION-ASSISTED DEPOSITION; THIN-FILMS; GROWTH; TEMPERATURE; SURFACE; SILICON; ORIGIN; Y2O3 AB Residual compressive stress due to plume-induced energetic particle bombardment in CeO2 films deposited by pulsed-laser deposition is reported. For laser ablation film growth in low pressures, stresses as high as 2 GPa were observed as determined by substrate curvature and four-circle x-ray diffraction. The amount of stress in the films could be manipulated by controlling the kinetic energies of the ablated species in the plume through gas-phase collisions with an inert background gas. The film stress decreased to near zero for argon background pressures greater than 50 mTorr. At these higher background pressures, the formation of nanoparticles in the deposited film was observed. (C) 1999 American Institute of Physics. [S0003-6951(99)04215-1]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Norton, DP (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Yoon, Sejin/F-7637-2013; Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 17 TC 20 Z9 20 U1 1 U2 7 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 APR 12 PY 1999 VL 74 IS 15 BP 2134 EP 2136 DI 10.1063/1.123780 PG 3 WC Physics, Applied SC Physics GA 183YT UT WOS:000079583000011 ER PT J AU Toet, D Thompson, MO Smith, PM Sigmon, TW AF Toet, D Thompson, MO Smith, PM Sigmon, TW TI Laser-assisted transfer of silicon by explosive hydrogen release SO APPLIED PHYSICS LETTERS LA English DT Article ID METAL-DEPOSITION; EXCIMER-LASER AB We present a technique for the transfer of silicon thin films. This transfer is effected by irradiating a hydrogenated amorphous silicon film deposited on a quartz substrate with an excimer laser pulse. The resulting release and accumulation of hydrogen at the film/substrate interface generates pressures sufficient to propel the silicon onto an adjacent glass receptor wafer. Transient optical transmission measurements indicate that the amorphous film is melted by the laser pulse and breaks into droplets during ejection. For fluences above 400 mJ/cm(2), the transferred films adhere well to the receptors and can be smoothed using a second laser irradiation. (C) 1999 American Institute of Physics. [S0003-6951(99)02315-3]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Cornell Univ, Dept Mat Sci & Engn, Ithaca, NY 14853 USA. RP Toet, D (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-271,7000 E Ave, Livermore, CA 94550 USA. OI Thompson, Michael/0000-0002-4933-009X NR 8 TC 14 Z9 14 U1 1 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 APR 12 PY 1999 VL 74 IS 15 BP 2170 EP 2172 DI 10.1063/1.123790 PG 3 WC Physics, Applied SC Physics GA 183YT UT WOS:000079583000023 ER PT J AU Prokes, K Nakotte, H de Boer, FR Torikachvili, MS Lacerda, AH Beyermann, W AF Prokes, K Nakotte, H de Boer, FR Torikachvili, MS Lacerda, AH Beyermann, W TI Electronic properties of U2Cu9Al SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID FERMI-LIQUID BEHAVIOR; HEAVY FERMIONS; KONDO PROBLEM; SYSTEMS AB We report on the electronic properties of U2Cu9Al, which crystallizes in a hexagonal structure with space group P6(3)/mmc. Anomalies in the temperature dependences of the transport, magnetic and thermal properties indicate that two magnetic transitions occur at similar to 9.5 K and similar to 31 K, the lower transition being of antiferromagnetic type. The assertion that the ground state of U2Cu9Al is antiferromagnetic is corroborated by magnetization measurements, which reveal a slight S shape in the M versus B curve with no indication of saturation in fields up to 18 T at 2.2 K. The electrical resistivity increases with lowering temperature, reaching a value of 284 mu Ohm cm at 0.26 K. Magnetoresistance studies at low temperatures show that a large part of the zero-field resistance is due to antiferromagnetic correlations, and a resistivity drop of similar to 30% is observed upon the application of a field of 18 T at 2 K. Another striking feature is the enhanced Sommerfeld coefficient gamma of similar to 210 mJ mol(U)(-1) K-2, extracted from extrapolation of the specific-heat data to T = 0 K, which we report here for the first time. Therefore, U2Cu9Al can be described as a moderately enhanced heavy-fermion system. C1 Hiroshima Univ, ADSM, Dept Quantum Matter, Higashihiroshima 7398526, Japan. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Univ Amsterdam, Van Der Waals Zeeman Inst, NL-1018 XE Amsterdam, Netherlands. San Diego State Univ, Dept Phys, San Diego, CA 92182 USA. Univ Calif Los Alamos Natl Lab, NHMFL, Pulsed Field Facil, Los Alamos, NM 87545 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. RP Prokes, K (reprint author), Hahn Meitner Inst Kernforsch Berlin GmbH, Abt NE BENSC, Glienickerstr 100, D-14109 Berlin, Germany. NR 23 TC 0 Z9 0 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 APR 12 PY 1999 VL 11 IS 14 BP 2955 EP 2964 DI 10.1088/0953-8984/11/14/011 PG 10 WC Physics, Condensed Matter SC Physics GA 186RW UT WOS:000079743600011 ER PT J AU Dutta, B Muller, DJ Nandi, S AF Dutta, B Muller, DJ Nandi, S TI Gauge mediated supersymmetry signals at the Tevatron involving tau-leptons SO NUCLEAR PHYSICS B LA English DT Article ID BREAKING MODELS; SUSY-BREAKING; SPARTICLE SPECTROSCOPY; MESSENGER SECTOR; PHENOMENOLOGY; CONSTRAINTS; GRAVITINO; COLLIDER; SPECTRUM; SEARCH AB We consider the phenomenology of GMSB models where the lighter stau is the next to lightest supersymmetric particle. In this situation the dominant signals for supersymmetry at the Tevatron are events where two or three high p(T) tau-leptons accompanied by large missing transverse energy are produced. This leads to signatures that are very different from the photonic signals for GMSB (where the lightest neutralino is the NLSP) and the dilepton and trilepton signals in the usual supergravity models (involving e and/or mu only) that have been investigated extensively. We find that the inclusive 2 tau-jet signature could be observable at the Tevatron Run II, while the inclusive 3 tau-jet signature could be important at Run III. (C) 1999 Elsevier Science B.V. C1 Univ Oregon, Inst Theoret Phys, Eugene, OR 97403 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. RP Dutta, B (reprint author), Univ Oregon, Inst Theoret Phys, Eugene, OR 97403 USA. NR 44 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 12 PY 1999 VL 544 IS 3 BP 451 EP 468 DI 10.1016/S0550-3213(98)00817-7 PG 18 WC Physics, Particles & Fields SC Physics GA 185AN UT WOS:000079646100001 ER PT J AU Czarnecki, A Melnikov, K AF Czarnecki, A Melnikov, K TI Two-loop QCD corrections to top quark width SO NUCLEAR PHYSICS B LA English DT Article DE top quark; QCD corrections; weak decays ID QUANTUM CHROMODYNAMICS; RADIATIVE-CORRECTIONS; FEYNMAN DIAGRAMS; HEAVY QUARKS; DECAY; THRESHOLD; SHELL AB We present O(alpha(s)(2)) corrections to the decay t --> bW in the limit of a very large top quark mass, m(t) much greater than m(w). We find that the O(alpha(s)(2)) effects decrease the top quark decay width Gamma(t) by about 2%: Gamma(t) = Gamma(0) (1 - 0.8 alpha(s)(m(t)) - 1.7 alpha(s)(2)). The complete corrections are smaller by about 24% than their estimate based on the BLM effects O(beta(0)alpha(s)(2)). We explain how to compute a new type of diagrams which contribute to Gamma(t --> bW) at the O(alpha(s)(2)) level. (C) 1999 Elsevier Science B.V. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Karlsruhe, Inst Theroet Teilchenphys, D-76128 Karlsruhe, Germany. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 37 TC 61 Z9 61 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 12 PY 1999 VL 544 IS 3 BP 520 EP 531 DI 10.1016/S0550-3213(98)00844-X PG 12 WC Physics, Particles & Fields SC Physics GA 185AN UT WOS:000079646100004 ER PT J AU Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, H Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Tajima, H Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lee, J Lorenc, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T AF Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, H Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Tajima, H Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lee, J Lorenc, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T CA CLEO Collaboration TI First observation of the decay B-0 -> D*D+*(-) SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTOR; LIMIT AB We have observed four fully reconstructed B-0 --> D*+D*- candidates in 5.8 x 10(6) Y(4S) --> B (B) over bar decays recorded with the CLEO detector. The background is estimated to be 0.31 +/- 0.10 events. The probability that the background could produce four or more signal candidates with the observed distribution among D*+ and D*- decay modes is 1.1 x 10(-4). The measured decay rate, B(B-0 --> D*+D*-) = [6.2(-2.9)(+4.0)(stat) +/- 1.0(syst)] x 10(-4), is large enough for this decay mode to be of interest for the measurement of a time-dependent CP asymmetry. [S0031-9007(99)08881-X]. C1 Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Victoria, BC, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. Univ Texas, Austin, TX 78712 USA. Yonsei Univ, Seoul 120749, South Korea. RP Artuso, M (reprint author), Syracuse Univ, Syracuse, NY 13244 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014; OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674 NR 18 TC 11 Z9 11 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 12 PY 1999 VL 82 IS 15 BP 3020 EP 3024 DI 10.1103/PhysRevLett.82.3020 PG 5 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200005 ER PT J AU Ackerstaff, K Airapetian, A Akopov, N Akushevich, I Amarian, M Aschenauer, EC Avakian, H Avakian, R Avetissian, A Bains, B Barrow, S Baumgarten, C Beckmann, M Belostotski, S Belz, JE Benisch, T Bernreuther, S Bianchi, N Blanchard, S Blouw, J Bottcher, H Borissov, A Brack, J Brauksiepe, S Braun, B Bray, B Brons, S Bruckner, W Brull, A Bruins, EEW Bulten, HJ Cadman, RV Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF Delheij, PPJ De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Duren, M Dvoredsky, A Elbakian, G Ely, J Emerson, J Fantoni, A Fechtchenko, A Ferstl, M Fick, D Fiedler, K Filippone, BW Fischer, H Fortune, HT Fox, B Frabetti, S Franz, J Frullani, S Funk, MA Gagunashvili, ND Galumian, P Gao, H Garber, Y Garibaldi, F Gavrilov, G Geiger, P Gharibyan, V Giordjian, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Grosshauser, C Guidal, MG Gute, A Gyurjyan, V Haas, JP Haeberli, W Hansen, JO Hasch, D Hausser, O Heinsius, FH Henderson, RS Henkes, T Henoch, M Hertenberger, R Holler, Y Holt, RJ Hoprich, W Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Jones, C Kaiser, R Kinney, E Kirsch, M Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Korsch, W Kozlov, V Kramer, LH Krause, B Krivokhijine, VG Kuckes, M Kummell, F Kyle, G Lachnit, W Lorenzon, W Lung, A Makins, NCR Martens, FK Martin, JW Masoli, F Mateos, A McAndrew, M McIlhany, K McKeown, RD Meissner, F Menden, F Mercer, D Metz, A Meyners, N Mikloukho, O Miller, CA Miller, MA Milner, RG Mitsyn, V Most, A Mozzetti, R Muccifora, V Nagaitsev, A Naryshkin, Y Nathan, AM Neunreither, F Niczyporuk, M Nowak, WD Nupieri, M Oelwein, P Ogami, H O'Neill, TG Openshaw, R Ouyang, J Owen, BR Papavassiliou, V Pate, SF Pitt, M Poolman, HR Potashov, S Potterveld, DH Povh, B Rakness, G Reali, A Redwine, R Reolon, AR Ristinen, R Rith, K Roloff, H Roper, G Rossi, P Rudnitsky, S Ruh, M Ryckbosch, D Sakemi, Y Savin, I Scarlett, C Schmidt, F Schmitt, H Schnell, G Schuler, KP Schwind, A Seibert, J Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Slavich, P Sowinski, J Spengos, M Steffens, E Stenger, J Stewart, J Stock, F Stoesslein, U Sutter, M Tallini, H Taroian, S Terkulov, A Thiessen, DM Thomas, E Tipton, B Trudel, A Tytgat, M Urciuoli, GM van Hunen, JJ de Vyver, RV van den Brand, JFJ van der Steenhoven, G Vetterli, MC Vikhrov, V Vincter, M Visser, J Volk, E Wander, W Welch, TP Williamson, SE Wise, T Wolfel, T Woller, K Yoneyama, S Zapfe-Duren, K Zohrabian, H Zurmuhle, R AF Ackerstaff, K Airapetian, A Akopov, N Akushevich, I Amarian, M Aschenauer, EC Avakian, H Avakian, R Avetissian, A Bains, B Barrow, S Baumgarten, C Beckmann, M Belostotski, S Belz, JE Benisch, T Bernreuther, S Bianchi, N Blanchard, S Blouw, J Bottcher, H Borissov, A Brack, J Brauksiepe, S Braun, B Bray, B Brons, S Bruckner, W Brull, A Bruins, EEW Bulten, HJ Cadman, RV Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF Delheij, PPJ De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Duren, M Dvoredsky, A Elbakian, G Ely, J Emerson, J Fantoni, A Fechtchenko, A Ferstl, M Fick, D Fiedler, K Filippone, BW Fischer, H Fortune, HT Fox, B Frabetti, S Franz, J Frullani, S Funk, MA Gagunashvili, ND Galumian, P Gao, H Garber, Y Garibaldi, F Gavrilov, G Geiger, P Gharibyan, V Giordjian, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Grosshauser, C Guidal, MG Gute, A Gyurjyan, V Haas, JP Haeberli, W Hansen, JO Hasch, D Hausser, O Heinsius, FH Henderson, RS Henkes, T Henoch, M Hertenberger, R Holler, Y Holt, RJ Hoprich, W Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Jones, C Kaiser, R Kinney, E Kirsch, M Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Korsch, W Kozlov, V Kramer, LH Krause, B Krivokhijine, VG Kuckes, M Kummell, F Kyle, G Lachnit, W Lorenzon, W Lung, A Makins, NCR Martens, FK Martin, JW Masoli, F Mateos, A McAndrew, M McIlhany, K McKeown, RD Meissner, F Menden, F Mercer, D Metz, A Meyners, N Mikloukho, O Miller, CA Miller, MA Milner, RG Mitsyn, V Most, A Mozzetti, R Muccifora, V Nagaitsev, A Naryshkin, Y Nathan, AM Neunreither, F Niczyporuk, M Nowak, WD Nupieri, M Oelwein, P Ogami, H O'Neill, TG Openshaw, R Ouyang, J Owen, BR Papavassiliou, V Pate, SF Pitt, M Poolman, HR Potashov, S Potterveld, DH Povh, B Rakness, G Reali, A Redwine, R Reolon, AR Ristinen, R Rith, K Roloff, H Roper, G Rossi, P Rudnitsky, S Ruh, M Ryckbosch, D Sakemi, Y Savin, I Scarlett, C Schmidt, F Schmitt, H Schnell, G Schuler, KP Schwind, A Seibert, J Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Slavich, P Sowinski, J Spengos, M Steffens, E Stenger, J Stewart, J Stock, F Stoesslein, U Sutter, M Tallini, H Taroian, S Terkulov, A Thiessen, DM Thomas, E Tipton, B Trudel, A Tytgat, M Urciuoli, GM van Hunen, JJ de Vyver, RV van den Brand, JFJ van der Steenhoven, G Vetterli, MC Vikhrov, V Vincter, M Visser, J Volk, E Wander, W Welch, TP Williamson, SE Wise, T Wolfel, T Woller, K Yoneyama, S Zapfe-Duren, K Zohrabian, H Zurmuhle, R CA HERMES Collaboration TI Observation of a coherence length effect in exclusive rho(0) electroproduction SO PHYSICAL REVIEW LETTERS LA English DT Article ID VECTOR-MESONS; COLOR TRANSPARENCY; NUCLEAR TRANSPARENCY; SCATTERING; PHOTOPRODUCTION; Q(2); QCD AB Exclusive incoherent electroproduction of the rho(0)(770) meson from H-1, H-2, He-3, and N-14 targets has been studied by the HERMES experiment at squared four-momentum transfer Q(2) > 0.4 GeV2 and positron energy loss nu from 9 to 20 GeV. The ratio of the N-14 to H-1 cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark-antiquark fluctuations with the nuclear medium. [S0031-9007(99)08858-4]. C1 DESY, D-22603 Hamburg, Germany. Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA. Univ Colorado, Nucl Phys Lab, Boulder, CO 80309 USA. DESY Zeuthen, D-15738 Zeuthen, Germany. Joint Inst Nucl Res, Dubna 141980, Russia. Univ Erlangen Nurnberg, Inst Phys, D-91058 Erlangen, Germany. Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Florida Int Univ, Dept Phys, Miami, FL 33199 USA. Univ Freiburg, Fak Phys, D-79104 Freiburg, Germany. Univ Ghent, Dept Subatom & Radiat Phys, B-9000 Ghent, Belgium. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Marburg, Inst Phys, D-35037 Marburg, Germany. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA. PN Lebedev Phys Inst, Moscow 117924, Russia. Univ Munich, Sekt Phys, D-85748 Garching, Germany. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Natl Inst Nucl Phys & High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Oregon State Univ, Dept Phys, Corvallis, OR 97331 USA. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Petersburg Nucl Phys Inst, St Petersburg 188350, Russia. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Ist Super Sanita, Fis Lab, I-00161 Rome, Italy. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. TRIUMF, Vancouver, BC V6T 2A3, Canada. Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Yerevan Phys Inst, Yerevan 375036, Armenia. RP DESY, D-22603 Hamburg, Germany. RI Gao, Haiyan/G-2589-2011; Gavrilov, Gennady/C-6260-2013; Holt, Roy/E-5803-2011; Terkulov, Adel/M-8581-2015; Cisbani, Evaristo/C-9249-2011 OI Cisbani, Evaristo/0000-0002-6774-8473 NR 26 TC 56 Z9 56 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 12 PY 1999 VL 82 IS 15 BP 3025 EP 3029 DI 10.1103/PhysRevLett.82.3025 PG 5 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200006 ER PT J AU Mainieri, R Rehacek, J AF Mainieri, R Rehacek, J TI Projective synchronization in three-dimensional chaotic systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID MASTER-SLAVE SYNCHRONIZATION; PHASE SYNCHRONIZATION; OSCILLATORS AB In partially linear systems, such as the Lorenz model, chaotic synchronization is possible in only some of the variables. We show that, for the nonsynchronizing variable, synchronization up to a scale factor is possible. We explain the mechanism for this projective form of chaotic synchronization in three-dimensional systems. Projective synchronization is illustrated for the Lorenz and disk dynamo systems. We also introduce a vector field that can be used to predict the scaling factor. [S0031-9007(99)08897-3]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. RP Mainieri, R (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B213, Los Alamos, NM 87545 USA. NR 16 TC 448 Z9 494 U1 0 U2 15 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 APR 12 PY 1999 VL 82 IS 15 BP 3042 EP 3045 DI 10.1103/PhysRevLett.82.3042 PG 4 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200010 ER PT J AU Radlinski, AP Radlinska, EZ Agamalian, M Wignall, GD Lindner, P Randl, OG AF Radlinski, AP Radlinska, EZ Agamalian, M Wignall, GD Lindner, P Randl, OG TI Fractal geometry of rocks SO PHYSICAL REVIEW LETTERS LA English DT Article ID SMALL-ANGLE-SCATTERING; NEUTRON-SCATTERING; FACILITY; SURFACES; ROUGH AB The analysis of small- and ultra-small-angle neutron scattering data for sedimentary rocks shows that the pore-rock fabric interface is a surface fractal (D-s = 2.82) over 3 orders of magnitude of the length scale and 10 orders of magnitude in intensity. The fractal dimension and scatterer size obtained from scanning electron microscopy image processing ate consistent with neutron scattering data. [S0031-9007(99)08945-0]. C1 Australian Geol Survey Org, Canberra, ACT 2601, Australia. Australian Natl Univ, Dept Appl Math, Canberra, ACT 0200, Australia. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Radlinski, AP (reprint author), Australian Geol Survey Org, GPO Box 378, Canberra, ACT 2601, Australia. OI Wignall, George/0000-0002-3876-3244; Agamalian, Michael/0000-0002-9112-2534 NR 23 TC 100 Z9 102 U1 0 U2 17 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 APR 12 PY 1999 VL 82 IS 15 BP 3078 EP 3081 DI 10.1103/PhysRevLett.82.3078 PG 4 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200019 ER PT J AU Braun, OM Bishop, AR Roder, J AF Braun, OM Bishop, AR Roder, J TI Multistep locked-to-sliding transition in a thin lubricant film SO PHYSICAL REVIEW LETTERS LA English DT Article ID KONTOROVA-TOMLINSON MODEL; STICK-SLIP MOTION; DRY FRICTION; ORIGIN; HYSTERESIS; FORCES AB Using Langevin simulations, we study dynamical transitions in a model three-layer atomic film confined between two rigid substrates moving with respect to each other. With the increase of a de force applied to the top substrate, first the middle layer of the lubricant film transitions from locked to sliding states; this regime shows a stick-slip behavior with a relatively high effective friction. Next, the layers closest to the substrates start to slide over the substrates, as well as with respect to the middle layer; the effective friction in this regime may be explained by energy losses due to the excitation of phonons in the lubricant. Finally, at high velocities the lubricant film decouples from the substrates and achieves a "flying" regime characterized by a very low friction coefficient. [S0031-9007(99)08913-9]. 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. Natl Ukrainian Acad Sci, Inst Phys, UA-252022 Kiev, Ukraine. RP Braun, OM (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 25 TC 14 Z9 14 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 APR 12 PY 1999 VL 82 IS 15 BP 3097 EP 3100 DI 10.1103/PhysRevLett.82.3097 PG 4 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200024 ER PT J AU Bhattacharya, A Zutic, I Valls, OT Goldman, AM Welp, U Veal, B AF Bhattacharya, A Zutic, I Valls, OT Goldman, AM Welp, U Veal, B TI Angular dependence of the nonlinear transverse magnetic moment of YBa2Cu3O6.95 in the Meissner state SO PHYSICAL REVIEW LETTERS LA English DT Article ID TEMPERATURE SPECIFIC-HEAT; PENETRATION DEPTH; FIELD DEPENDENCE; PAIRING STATE; MIXED-STATE; SUPERCONDUCTORS; YBA2CU3O7-DELTA; ANISOTROPY AB The angular dependence of the nonlinear transverse magnetic moment of untwinned high-quality single crystals of YBa2Cu3O6.95 has been studied at a temperature of 2.5 K using a low frequency ac technique. The absence of any signature at angular period 2 pi/4 is analyzed in light of the numerical predictions of such a signal for a pure d(x)2(-y)2 order parameter with line nodes. Implications of this null result for the existence of a nonzero gap at all angles on the Fermi surface are discussed. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Bhattacharya, A (reprint author), Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. RI Bhattacharya, Anand/G-1645-2011 OI Bhattacharya, Anand/0000-0002-6839-6860 NR 27 TC 43 Z9 43 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 APR 12 PY 1999 VL 82 IS 15 BP 3132 EP 3135 DI 10.1103/PhysRevLett.82.3132 PG 4 WC Physics, Multidisciplinary SC Physics GA 185AP UT WOS:000079646200033 ER PT J AU Zioutas, K Aalseth, CE Abriola, D Avignone, FT Brodzinski, RL Collar, JI Creswick, R Di Gregorio, DE Farach, H Gattone, AO Guerard, CK Hasenbalg, F Hasinoff, M Huck, H Liolios, A Miley, HS Morales, A Morales, J Nikas, D Nussinov, S Ortiz, A Savvidis, E Scopel, S Sievers, P Villar, JA Walckiers, L AF Zioutas, K Aalseth, CE Abriola, D Avignone, FT Brodzinski, RL Collar, JI Creswick, R Di Gregorio, DE Farach, H Gattone, AO Guerard, CK Hasenbalg, F Hasinoff, M Huck, H Liolios, A Miley, HS Morales, A Morales, J Nikas, D Nussinov, S Ortiz, A Savvidis, E Scopel, S Sievers, P Villar, JA Walckiers, L TI A decommissioned LHC model magnet as an axion telescope SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE solar axions; LHC; superconducting magnets; dark matter ID SOLAR AXIONS; SN 1987A; CP CONSERVATION; SEARCH; PARTICLES; LIMITS; CONSTRAINTS; CONVERSION; EVOLUTION; DETECTORS AB The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be 33 days/yr with the magnet on a tracking table capable of +/ -5 degrees in the vertical direction and +/- 40 degrees in the horizontal direction. The existing lower bound on the axion-to-photon coupling constant can be improved by a factor between 30 and 100 in 3 yr, i.e.. g(a gamma gamma) less than or similar to 9 X 10(-11) GeV-1 for axion masses less than or similar to 1 eV. This value falls within the existing open axion mass window. The same set-up can simultaneously search for low- and high-energy celestial axions, or axion-like particles, scanning the sky as the Earth rotates and orbits the Sun. (C) 1999 Elsevier Science B.V. All rights reserved. C1 CERN, CH-1211 Geneva 23, Switzerland. Univ Thessaloniki, Dept Phys, GR-54006 Thessaloniki, Greece. Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. CNEA, TANDAR Lab, Dept Phys, Buenos Aires, DF, Argentina. Pacific NW Lab, Richland, WA 99352 USA. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Univ Zaragoza, Fac Ciencias, Lab Fis Nucl & Atlas Energias, E-50009 Zaragoza, Spain. Tel Aviv Univ, Dept Phys, Tel Aviv, Israel. RP Collar, JI (reprint author), CERN, CH-1211 Geneva 23, Switzerland. EM collar@mail.cern.ch RI Villar, Jose Angel/K-6630-2014 OI Villar, Jose Angel/0000-0003-0228-7589 NR 54 TC 72 Z9 72 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 APR 11 PY 1999 VL 425 IS 3 BP 480 EP 487 DI 10.1016/S0168-9002(98)01442-9 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183UX UT WOS:000079573200007 ER PT J AU Atamantchuk, A Bondar, N Golovtsov, V Golyash, A Razmyslovich, B Terentyev, N Vorobyov, A Skow, D Ferbel, T Hammer, C Slattery, P Moinester, MA Ocherashvili, A Steiner, V AF Atamantchuk, A Bondar, N Golovtsov, V Golyash, A Razmyslovich, B Terentyev, N Vorobyov, A Skow, D Ferbel, T Hammer, C Slattery, P Moinester, MA Ocherashvili, A Steiner, V TI Design and performance of the fermilab E781 (SELEX) hardware scattering trigger SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE trigger; small-angle scattering detector AB The design and performance of the Fermilab E781 (SELEX) Hardware Scattering Trigger (HST) are described. This trigger functioned by distinguishing beam scattering at small angles ( > 150 mu rad) from non-interacting beam. Six 50 mu m pitch silicon planes grouped in three (x,y) stations, two before and one after the target, were used as the particle detectors. The triggering system involved 1920 channels of readout providing data to the Fast Encoding and Readout System (FERS) with programmable trigger logic processor. The overall system was tested successfully at Fermilab during the 1996-1997 fixed target run. The encoding time of the readout part of the FERS device was 30 ns and the processor decision time was 55 ns. The HST provided an output signal 250 ns after beam traversal of the target. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Petersburg Nucl Phys Inst, Gatchina, Russia. Univ Rochester, Rochester, NY USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. RP Skow, D (reprint author), Fermi Natl Accelerator Lab, POB 500 MS 369, Batavia, IL 60510 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 1999 VL 425 IS 3 BP 529 EP 535 DI 10.1016/S0168-9002(98)01429-6 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183UX UT WOS:000079573200014 ER PT J AU Sambruna, RM Ghisellini, G Hooper, E Kollgaard, RI Pesce, JE Urry, CM AF Sambruna, RM Ghisellini, G Hooper, E Kollgaard, RI Pesce, JE Urry, CM TI ASCA and contemporaneous ground-based observations of the BL Lacertae objects 1749+096 and 2200+420 (BL Lac) SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (1749+096); BL Lacertae objects : individual (2200+420); galaxies : active; radiation mechanisms : nonthermal; X-rays : galaxies ID X-RAY-SPECTRA; EXTRAGALACTIC RADIO-SOURCES; ACTIVE GALACTIC NUCLEI; LOCAL INTERSTELLAR CO; GAMMA-RAY; MULTIFREQUENCY OBSERVATIONS; ENERGY-DISTRIBUTIONS; EGRET OBSERVATIONS; COMPLETE SAMPLE; BLAZARS AB We present ASCA observations of the radio-selected BL Lacertae objects 1749+096 (z = 0.32) and 2300+420 (BL Lac, z = 0.069) performed in 1995 September and November, respectively. The ASCA spectra of both sources can be described as a first approximation by a power law with photon index Gamma similar to 2. This is flatter than for most X-ray-selected BL Lacs observed with ASCA, in agreement with the predictions of current blazar unification models. While 1749+096 exhibits tentative evidence for spectral flattening at low energies, a concave continuum is detected for 2200+420: the steep low-energy component is consistent with the high-energy tail of the synchrotron emission responsible for the longer wavelengths, while the harder tail at higher energies is the onset of the Compton component. The two BL Lacs were observed with ground-based telescopes from radio to TeV energies contemporaneously with ASCA. The spectral energy distributions are consistent with synchrotron self-Compton emission from a single homogeneous region shortward of the IR/optical wavelengths, with a second component in the radio domain related to a more extended emission region. For 2200+420, comparing the 1995 November state with the optical/GeV flare of 1997 July, we find that models requiring inverse Compton scattering of external photons provide a viable mechanism for the production of the highest (GeV) energies during the flare. In particular, an increase of the external radiation density and of the power injected in the jet can reproduce the flat gamma-ray continuum observed in 1997 July. A directly testable prediction of this model is that the line luminosity in 2200+420 should vary shortly after(similar to 1 month) a nonthermal synchrotron flare. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Osservatorio Astron Brera, I-22055 Merate, LC, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Sambruna, RM (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 65 TC 35 Z9 36 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 APR 10 PY 1999 VL 515 IS 1 BP 140 EP 152 DI 10.1086/307005 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 195AF UT WOS:000080226400011 ER PT J AU Shashkov, M Wendroff, B AF Shashkov, M Wendroff, B TI A composite scheme for gas dynamics in Lagrangian coordinates SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Lagrangian gas dynamics; composite scheme; Lax-Wendroff; Lax-Friedrichs ID CONSERVATION AB One cycle of a composite finite difference scheme is defined as several time steps of an oscillatory scheme such as Lax-Wendroff followed by one step of a diffusive scheme such as Lax-Friedrichs. We apply this idea to gas dynamics in Lagrangian coordinates. We show numerical results in two dimensions for Noh's infinite strength shock problem and the Sedov blast wave problem, and for several one-dimensional problems including a Riemann problem with a contact discontinuity. For Noh's problem the composite scheme produces a better result than that obtained with a more conventional Lagrangian code. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Shashkov, M (reprint author), Univ Calif Los Alamos Natl Lab, T-7,MS-B284, Los Alamos, NM 87545 USA. EM misha@t7.lanl.gov; bbw@lanl.gov NR 11 TC 9 Z9 9 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR 10 PY 1999 VL 150 IS 2 BP 502 EP 517 DI 10.1006/jcph.1999.6192 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 185UV UT WOS:000079690000008 ER PT J AU Roberts, JJ Tyburczy, JA AF Roberts, JJ Tyburczy, JA TI Partial-melt electrical conductivity: Influence of melt composition SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID OCEANIC UPPER-MANTLE; POLYCRYSTALLINE OLIVINE; ROCK; TRANSPORT; SYSTEMS; PERMEABILITY; PREDICTION; SOUNDINGS; IMPEDANCE; PRESSURE AB The electrical conductivity of a partial melt is influenced by many factors, including melt conductivity, crystalline conductivity, and melt fraction, each of which is influenced by temperature. We have performed measurements of bulk conductivity as a function of temperature of an Fo(80)-basalt partial melt between 684 degrees and 1244 degrees C at controlled oxygen fugacity. Melt fraction and composition variations with temperature calculated using MELTS [Ghiorso and Sack, 1995] indicate that the effect on melt conductivity of changing melt composition is balanced by changes in temperature (T). Thus bulk conductivity as a function of T or melt fraction in this system can be calculated assuming a constant melt conductivity. The bulk conductivity is well modeled by simple parallel calculations, by the Hashin-Shtrikman upper bound, or by Archie's law (sigma(partial) (melt)/sigma(melt) = C1Xmn). We estimate apparent values of the Archie's law parameters between 1150 degrees and 1244 degrees C as C-1 = 0.73 +/- 0.02 and n = 0.98 +/- 0.01. Estimates of the permeability of the system are obtained by using an electrical conductivity-critical scale length relationship and range from similar to 10(-14) to 10(-18) m(2), comparing favorably with previously published values. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. RP Roberts, JJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-201, Livermore, CA 94551 USA. EM roberts17@llnl.gov; jim.tyburczy@asu.edu NR 48 TC 110 Z9 119 U1 3 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1999 VL 104 IS B4 BP 7055 EP 7065 DI 10.1029/1998JB900111 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 184VF UT WOS:000079633900001 ER PT J AU Olsson, WA AF Olsson, WA TI Theoretical and experimental investigation of compaction bands in porous rock SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID LOCALIZATION; COMPRESSION; DEFORMATION; SANDSTONES AB Field investigators have recently discovered thin, tabular zones of pure compressional deformation that they called compaction bands. These bands were found in association with shear bands and were postulated to be genetically related to them. At the laboratory scale, compaction bands have been noticed in association with boreholes and preexisting, artificial shear cracks subjected to compressive stress fields. Natural compaction bands are noticeable in outcrops because of their resistance to weathering; however, they may be more difficult to discern on freshly cut rock surfaces such as drill core or borehole walls. Because of the much reduced porosity in the compaction bands, these structures are potentially important as permeability barriers in reservoirs and aquifers in porous rocks. For bands associated with boreholes, the crushed material can be washed into the borehole contributing to sand production and possibly altering the stability of the borehole. This paper examines a theoretical framework that explains these features as a constitutive instability leading to localized compaction in a way completely analogous to shear strain localization. Conventional triaxial experiments on Castlegate sandstone resulted in compaction bands. In addition, thick deformation bands having normals at low angles to the maximum compression are present in some specimens. C1 Sandia Natl Labs, Geomech Dept, Albuquerque, NM 87185 USA. RP Olsson, WA (reprint author), Sandia Natl Labs, Geomech Dept, MS 0751, Albuquerque, NM 87185 USA. EM waolsso@sandia.gov NR 18 TC 155 Z9 166 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1999 VL 104 IS B4 BP 7219 EP 7228 DI 10.1029/1998JB900120 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 184VF UT WOS:000079633900011 ER PT J AU Raptis, CA Pratt, ST AF Raptis, CA Pratt, ST TI Rotational interactions in autoionizing Rydberg states of ammonia SO CHEMICAL PHYSICS LETTERS LA English DT Article ID QUANTUM-DEFECT THEORY; HIGH-RESOLUTION; PHOTOELECTRON-SPECTROSCOPY; PHOTOIONIZATION SPECTRUM; FIELD-IONIZATION; ENERGY; DYNAMICS; PREDISSOCIATION; THRESHOLD; H-2 AB Double-resonance ionization spectra via selected rotational levels of the (C) over tilde' (1)A'(0100) state of ammonia show direct evidence for rotational-electronic perturbations between Rydberg series converging to different rotational states of NH3+ (X) over tilde (2)A(2)" (0100), and for rotational autoionization when it is energetically allowed. The simplicity of the double resonance spectra is quite striking, and rotational interactions with Delta N+ = -1, Delta K+ = 0 are found to be most important. The results have implications for understanding intensities in rotationally resolved threshold photoelectron spectra and for extracting ionization onsets from photoionization mass spectra. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Pratt, ST (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 31 TC 9 Z9 9 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 APR 9 PY 1999 VL 303 IS 3-4 BP 281 EP 288 DI 10.1016/S0009-2614(99)00245-6 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189JE UT WOS:000079900700005 ER PT J AU Nieh, TG Mukai, T Liu, CT Wadsworth, J AF Nieh, TG Mukai, T Liu, CT Wadsworth, J TI Superplastic behavior of a Zr-10Al-5Ti-17.9Cu-14.6Ni metallic glass in the supercooled liquid region SO SCRIPTA MATERIALIA LA English DT Article ID AMORPHOUS-ALLOYS; DEFORMATION; CRYSTALLIZATION C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Osaka Municipal Tech Res Inst, Joto Ku, Osaka 5368553, Japan. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Nieh, TG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-350, Livermore, CA 94551 USA. 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; Liu, Chain Tsuan/0000-0001-7888-9725 NR 19 TC 75 Z9 85 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 APR 9 PY 1999 VL 40 IS 9 BP 1021 EP 1027 DI 10.1016/S1359-6462(99)00071-8 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 201ER UT WOS:000080582500008 ER PT J AU Fenter, P Schreiber, F Berman, L Scoles, G Eisenberger, P Bedzyk, MJ AF Fenter, P Schreiber, F Berman, L Scoles, G Eisenberger, P Bedzyk, MJ TI On the structure and evolution of the buried S/Au interface in self-assembled monolayers: X-ray standing wave results (vol 412, pg 213, 1998) SO SURFACE SCIENCE LA English DT Correction C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08542 USA. Columbia Univ, Lamont Doherty Earth Observ, New York, NY 10027 USA. Northwestern Univ, Dept Mat Sci, Evanston, IL 60208 USA. RP Fenter, P (reprint author), Argonne Natl Lab, Div Environm Res, Bldg 203,9700 S Cass Ave, Argonne, IL 60439 USA. RI Bedzyk, Michael/B-7503-2009; Bedzyk, Michael/K-6903-2013; Schreiber, Frank/J-3311-2014 OI Schreiber, Frank/0000-0003-3659-6718 NR 1 TC 16 Z9 16 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 APR 9 PY 1999 VL 425 IS 1 BP 138 EP 139 PG 2 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 188AB UT WOS:000079820400020 ER PT J AU Lucas, CA Markovic, NM Ross, PN AF Lucas, CA Markovic, NM Ross, PN TI The adsorption and oxidation of carbon monoxide at the Pt(111)/electrolyte interface: atomic structure and surface relaxation SO SURFACE SCIENCE LA English DT Letter DE atomic structure; carbon monoxide; Pt(111); surface relaxation ID CO; PT(111); CHEMISORPTION AB Using in-situ X-ray diffraction we have studied the adsorption of CO onto Pt(111) in pure perchloric acid. The adsorption of CO at an applied electrode potential of 0.05 V (versus the reversible hydrogen electrode) causes expansion of the topmost Pt atomic layer by similar to 4% of the bulk lattice spacing. Ar this potential the adsorbed CO forms a compressed p(2 x 2) adlayer which fully covers the Pt surface. As the potential is stepped positively, the p(2 x 2) structure undergoes an order-disorder transition which appears to be triggered by oxidation of a small fraction of the adsorbed CO adlayer and is reversible or irreversible according to the overpressure of CO. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Lucas, CA (reprint author), Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. OI Lucas, Christopher/0000-0001-5743-3868 NR 22 TC 92 Z9 92 U1 4 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 9 PY 1999 VL 425 IS 1 BP L381 EP L386 DI 10.1016/S0039-6028(99)00252-6 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 188AB UT WOS:000079820400005 ER PT J AU Sun, X Miller, WH AF Sun, X Miller, WH TI Forward-backward initial value representation for semiclassical time correlation functions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THERMAL RATE CONSTANTS; COMPLEX MOLECULAR-SYSTEMS; QUANTUM DYNAMICS; DISSIPATIVE SYSTEMS; REAL-TIME; PROPAGATION; APPROXIMATIONS; COLLISIONS; FORMALISM; INTEGRALS AB The semiclassical (SC) initial value representation (IVR) for the time evolution operator e(-i (H) over cap t/(h) over bar) involves a phase space integral over the initial conditions of classical trajectories. It is shown in this paper how an IVR for the two time evolution operators in a typical quantum mechanical time correlation function, C-AB (t)=tr[(A) over cap e (i (H) over cap t/(h) over bar) (B) over cap e (-i (H) over cap t/(h) over bar)], can be combined into one such phase space integral; i.e., time evolution from 0 to t and from t to 0 is combined into one overall SC-IVR propagation. This not only reduces the dimensionality of the phase space average, but the forward-backward (FB) nature of the net trajectory has a partial self-cancellation that reduces the oscillatory behavior of the integrand. Several applications of this FB-IVR to reactive flux correlation functions are presented to illustrate its possibilities. (C) 1999 American Institute of Physics. [S0021-9606(99)00113-0]. 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 57 TC 184 Z9 184 U1 3 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 APR 8 PY 1999 VL 110 IS 14 BP 6635 EP 6644 DI 10.1063/1.478571 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700007 ER PT J AU Kendrick, BK Pack, RT Walker, RB Hayes, EF AF Kendrick, BK Pack, RT Walker, RB Hayes, EF TI Hyperspherical surface functions for nonzero total angular momentum. I. Eckart singularities SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COLLISION-INDUCED DISSOCIATION; QUANTUM REACTIVE SCATTERING; STATE TRANSITION-PROBABILITIES; GEOMETRIC PHASE; 3 PARTICLES; H+D-2->HD+D REACTION; VARIATIONAL METHOD; CHEMICAL-REACTIONS; H+O-2 SCATTERING; CROSS-SECTIONS AB A new hybrid numerical technique which utilizes both the DVR (Discrete Variable Representation) and FBR (Finite Basis Representation) to solve for the full 5D surface functions in the three-atom problem in hyperspherical coordinates for nonzero total angular momentum (J not equal 0) is reported. This method accurately treats the Eckart singularities in the kinetic energy operator which occur at both the north pole and equator of the 2D hypersphere in body-frame coordinates. The effects of the Eckart singularities on the surface function energies for HD2 are investigated and it is shown that an accurate treatment of these singularities is crucial in order to obtain the correct results. An improper treatment of the Eckart singularities could be a source for some of the discrepancies between recent experimental results and theory for the reaction H+D-2-->HD+D. (C) 1999 American Institute of Physics. [S0021-9606(99)00914-9]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. RP Kendrick, BK (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-12,MS-B268, Los Alamos, NM 87545 USA. NR 66 TC 63 Z9 63 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 1999 VL 110 IS 14 BP 6673 EP 6693 DI 10.1063/1.478574 PG 21 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700010 ER PT J AU Lenzer, T Furlanetto, MR Pivonka, NL Neumark, DM AF Lenzer, T Furlanetto, MR Pivonka, NL Neumark, DM TI Zero electron kinetic energy and threshold photodetachment spectroscopy of XenI- clusters (n=2-14): Binding, many-body effects, and structures SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NONADDITIVE INTERMOLECULAR FORCES; DER-WAALS TRIMERS; ANION PHOTOELECTRON-SPECTROSCOPY; INTERACTIONS INVOLVING HE; 3-BODY INTERACTIONS; AB-INITIO; MULTIPOLE POLARIZABILITIES; DISPERSION COEFFICIENTS; INFRARED-SPECTROSCOPY; AR2HCL CLUSTERS AB XenI- van der Waals clusters have been investigated by anion zero electron kinetic energy (ZEKE) and partially discriminated threshold photodetachment (PDTP) spectroscopy. The experiments yield size-dependent electron affinities (EAs) and electronic state splittings between the X, I, and II states accessed by photodetachment. Cluster minimum energy structures have been determined by extensive simulated annealing molecular dynamics calculations using Xe-I(-) pair potentials from anion ZEKE spectroscopy and various nonadditive terms. The EAs calculated without many-body effects overestimate the experimental EAs by up to 3000 cm(-1). Repulsive many-body induction in the anion clusters is found to be the dominant nonadditive effect, though the attractive interaction between the iodide charge and the Xe-2 exchange quadrupole is also important. Unique global minimum energy structures for the anion clusters arise from the influence of the many-body terms, yielding, e. g., arrangements with a closed shell of xenon atoms around the iodide anion for the clusters with n = 12-14. The specific dependence of the EA curve on cluster size allows us to refine the absolute Xe-I bond lengths for the anion, X, I, and II state diatomic potentials to within +/-0.05 Angstrom. (C) 1999 American Institute of Physics. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Lenzer, T (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM dan@radon.cchem.berkeley.edu RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 95 TC 39 Z9 40 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 1999 VL 110 IS 14 BP 6714 EP 6731 DI 10.1063/1.478577 PG 18 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700013 ER PT J AU Bracker, AS Wouters, ER Suits, AG Vasyutinskii, OS AF Bracker, AS Wouters, ER Suits, AG Vasyutinskii, OS TI Imaging the alignment angular distribution: State symmetries, coherence effects, and nonadiabatic interactions in photodissociation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENHANCED MULTIPHOTON IONIZATION; REACTION-PRODUCTS; ATOMIC FLUORESCENCE; DIATOMIC-MOLECULES; PHOTO-DISSOCIATION; CHLORINE MOLECULE; POLARIZATION; PHOTOFRAGMENTS; ORIENTATION; EXCITATION AB We establish a rigorous theoretical connection between measurements of the angular distribution of atomic photofragment alignment and the underlying dynamics of molecular photodissociation. We derive laboratory and molecular-frame angular momentum state multipoles as a function of photofragment recoil angles. These state multipoles are expressed in terms of alignment anisotropy parameters, which provide information on state symmetries, coherence effects, and nonadiabatic interactions. The method is intended for analysis of experimental data obtained with two-photon spectroscopy and ion imaging techniques, although it is readily modified for treating Doppler or time-of-flight mass spectrometer peak profiles. We have applied this method to the photodissociation of Cl-2 at 355 nm, where we observe strong alignment in the ground state chlorine atom photofragments. Our analysis demonstrates that there are important contributions to the alignment from both incoherent and coherent perpendicular excitation. We also show that the existence of atomic alignment due to coherence requires that nonadiabatic transitions occur at long range. (C) 1999 American Institute of Physics. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Russian Acad Sci, AF Ioffe Physicotech Inst, St Petersburg 194021, Russia. RP Bracker, AS (reprint author), USN, Res Lab, 4555 Overlook Ave SW, Washington, DC 20375 USA. EM agsuits@lbl.gov; osv@pms.ioffe.rssi.ru NR 61 TC 124 Z9 125 U1 1 U2 17 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 APR 8 PY 1999 VL 110 IS 14 BP 6749 EP 6765 DI 10.1063/1.478668 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700016 ER PT J AU Brock, LR Mischler, B Rohlfing, EA AF Brock, LR Mischler, B Rohlfing, EA TI Laser-induced fluorescence spectroscopy of the (B)over-tilde(2)Pi-(X)over-tilde(2)A '' band system of HCCO and DCCO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FLASH KINETIC SPECTROSCOPY; MICROWAVE SPECTROSCOPY; BRANCHING RATIO; COUPLED-CLUSTER; RADICALS; STATES; PHOTODISSOCIATION; CONSTANTS; MOLECULES; SPECTRA AB The electronic spectroscopy of the (B) over tilde( 2)II-(X) over tilde (2)A " band system of the ketenyl radical, H(D)CCO, is investigated using laser-induced fluorescence (LIF) in a free-jet environment. Vibronically resolved excitation spectra for HCCO are obtained from 33 400 cm(-1) to 35 100 cm(-1); at higher energies the LIF spectra cutoff due to a rapid increase in the rate of predissociation. The parallel transitions from K-a" = 1 in the ground state to the spin-orbit levels, (II3/2)-I-2 and (II1/2)-I-2, of the origin of the (B) over tilde state are completely rotationally resolved for both HCCO and DCCO. Four other parallel transitions originating from K-a" = 0 in the ground state and terminating on levels of Sigma vibronic symmetry are observed and assigned to the two pairs of S states derived from one quantum of excitation in each of the Renner-Teller active modes, the CCO and CCH(D) bend. Rotational analysis provides effective rotational constants and spin-rotation (orbit) couplings for each of these levels. In addition to the Renner-Teller and spin-orbit couplings, there is substantial evidence for additional perturbations among the low-lying bending levels in the (B) over tilde (II)-I-2 state of ketenyl. (C) 1999 American Institute of Physics. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Brock, LR (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 42 TC 24 Z9 24 U1 1 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 APR 8 PY 1999 VL 110 IS 14 BP 6773 EP 6781 DI 10.1063/1.478581 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700018 ER PT J AU Cynn, H Yoo, CS Sheffield, SA AF Cynn, H Yoo, CS Sheffield, SA TI Phase transition and decomposition of 90% hydrogen peroxide at high pressures SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ICE-VII; GPA; H2O-ICE; RAMAN AB Physical and chemical changes of 90 wt% hydrogen peroxide have been investigated to pressures of 12 GPa by using a diamond-anvil cell, synchrotron x-ray diffraction, and Raman spectroscopy. Hydrogen peroxide freezes at 1.5 GPa and ambient temperature into a tetragonal structure (P4(1)2(1)2, Z = 4, denoted as H2O2-I. This is the same transition that has previously been reported in this material at 253 K. The unit cell parameters at 6.3 GPa are a = 3.759 Angstrom, c = 7.397 Angstrom, and V = 15.74 cm(3)/mol, representing 21% compression from that at ambient pressure. H2O2-I has been found to transform into a high pressure phase H2O2-II at 7.5 GPa, and it decomposes into water and oxygen at the onset of melting, which may be incongruent. In contrast to water, hydrogen peroxide exhibits a relatively simple polymorphism and a positive initial slope of the melting curve at high pressures. (C) 1999 American Institute of Physics. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Cynn, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 24 TC 9 Z9 9 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 1999 VL 110 IS 14 BP 6836 EP 6843 DI 10.1063/1.478588 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 183ER UT WOS:000079541700025 ER PT J AU Bautista, JA Hiller, RG Sharples, FP Gosztola, D Wasielewski, M Frank, HA AF Bautista, JA Hiller, RG Sharples, FP Gosztola, D Wasielewski, M Frank, HA TI Singlet and triplet energy transfer in the peridinin-chlorophyll a protein from Amphidinium carterae SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LIGHT-HARVESTING COMPLEX; A-PROTEIN; PHOTOSYNTHETIC BACTERIA; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; CAROTENOIDS; DYNAMICS; RELAXATION; POLYENES; B800-850 AB The spectroscopic properties of peridinin in solution, and the efficiency and dynamics of energy transfer from peridinin to chlorophyll a in the peridinin-chlorophyll-protein (PCP) from Amphidinium carterae, were studied by steady-state absorption, fluorescence, fluorescence excitation, and fast transient optical spectroscopy. Steady-state measurements of singlet energy transfer from peridinin to chlorophyll revealed an 88 +/- 2% efficiency. Fast-transient absorption experiments showed that the excited S-1 state of peridinin decayed in 13.4 +/- 0.6 ps in methanol and 3.1 +/- 0.3 ps in the PCP complex after direct excitation of the carotenoid. The onset of the bleaching of the chlorophyll absorption band at 672 nm, signifying the arrival of the excitation from the carotenoid, occurred in 3.2 +/- 0.3 ps. These data show that the primary route of energy transfer from peridinin to chlorophyll in the PCP complex is through the S1 state of peridinin. Nanosecond time-resolved transient optical, spectroscopy revealed that chlorophyll triplet states are efficiently quenched by peridinin whose triplet state subsequently decays with a lifetime of 10 +/- 1 mu s in the PCP complex. Close association between the peridinins and chlorophylls, which is clearly evident in the 3-D structure of the PCP complex, along with proper alignment of pigments and energy state matching are responsible for the high efficiencies of the photochemical processes. C1 Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. Macquarie Univ, Sch Biol Sci, N Ryde, NSW 2109, Australia. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Frank, HA (reprint author), Univ Connecticut, Dept Chem, 55 N Eagleville Rd, Storrs, CT 06269 USA. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 35 TC 119 Z9 120 U1 1 U2 4 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 APR 8 PY 1999 VL 103 IS 14 BP 2267 EP 2273 DI 10.1021/jp983943f PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 188GC UT WOS:000079837600014 ER PT J AU Pieper, J Ratsep, M Jankowiak, R Irrgang, KD Voigt, J Renger, G Small, GJ AF Pieper, J Ratsep, M Jankowiak, R Irrgang, KD Voigt, J Renger, G Small, GJ TI Q(y)-level structure and dynamics of solubilized light-harvesting complex II of green plants: Pressure and hole burning studies SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSIENT ABSORPTION-SPECTROSCOPY; TEMPERATURE-DEPENDENT ABSORPTION; ENERGY-TRANSFER PROCESSES; EXCITON LEVEL STRUCTURE; A/B PROTEIN COMPLEX; ANTENNA COMPLEX; PHOTOSYSTEM-II; RHODOBACTER-SPHAEROIDES; STEADY-STATE; LHC-II AB Nonphotochemical hole burning and pressure-dependent absorption and hole-burning results are presented for the isolated (disaggregated) chlorophyll alb light-harvesting II trimer antenna complex of green plants. Analysis of the 4.2 K burn-fluence dependent hole spectra and zero-phonon hole action spectra indicates that the three lowest energy states (Q(y)) lie at 677.1, 678.4 and 679.8 nm, Their combined absorption intensity is equivalent to that of three Chi a molecules. The inhomogeneous broadening of their absorption bands is 70 cm(-1). It is argued that these states, separated by 30 cm(-1), are associated with thr lowest energy state of the trimer subunit with the 30 cm(-1) separations due to the indigenous structural heterogeneity of protein complexes. The linear electron-phonon coupling of the 679.8 nm state is weak and characterized, in part, by a mean phonon frequency of omega(m) = 18 cm(-1) and Huang-Rhys factor of S-m = 0.8, values which yield the comet Stokes shift for fluorescence from the 679.8 nm state at 4.2 Ii. The temperature dependence of the zerophonon hole (ZPH) width for that state is consistent with optical dynamics due to coupling with glasslike two-level systems of the protein. The ZPH width at 1.9 K( is 0.037 cm(-1). Satellite hole structure produced by burning in the above three states as well as their low linear pressures shift rates (about - 0.08 cm(-1)/MPa) indicate that the Chi a molecule of the subunit associated with them is weakly coupled to other Chi molecules. The linear pressure shift rates for the main Q(y)-absorption bands are also low. The shift rates appear to be dictated by protein-Chi interactions rather than excitonic couplings. Holes burned into the 650 nm absorption band reveal energy transfer times of 1 ps and similar to 100 fs which are discussed in terms of time domain measurements of the Chi b --> Chi a transfer rates (Connelly et al. J. Phys. Chem. B 1997, 101, 1902). The holewidths associated with burning into the 676 nm absorption band lead to Chl a --> Chl a transfer times in the 6-10 ps range, in good agreement with the time domain values (Savikhin et al. Biophys. J. 1994, 66, 1597). C1 Tech Univ Berlin, Max Volmer Inst, D-10623 Berlin, Germany. Humboldt Univ, Inst Phys, D-10099 Berlin, Germany. US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Small, GJ (reprint author), Tech Univ Berlin, Max Volmer Inst, D-10623 Berlin, Germany. NR 66 TC 62 Z9 64 U1 3 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 APR 8 PY 1999 VL 103 IS 14 BP 2412 EP 2421 DI 10.1021/jp983957l PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 188GC UT WOS:000079837600032 ER PT J AU Pieper, J Irrgang, KD Ratsep, M Schrotter, T Voigt, J Small, GJ Renger, G AF Pieper, J Irrgang, KD Ratsep, M Schrotter, T Voigt, J Small, GJ Renger, G TI Effects of aggregation on trimeric light-harvesting complex II of green plants: A hole-burning study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID A/B-BINDING PROTEINS; EXCITATION-ENERGY; PHOTOSYSTEM-II; FLUORESCENCE; SPECTROSCOPY; ABSORPTION; SPECTRA; ANTENNA AB Low-temperature absorption, fluorescence, and persistent hole-burned spectra are reported for aggregates of the trimeric light-harvesting antenna complex of photosystem II (LHC II). The lowest energy Q(y)-state was found to lie at 681.5 nm on the basis of hole spectra, which corresponds to a 3 nm red shift relative to the isolated LHC II trimer (Pieper et al. J. Phys. Chem. B 1999,2412, accompanying paper). The electron-phonon coupling of the 681.5 nm state is characterized by S similar to 0.8 and coupling to phonons with a mean frequency of similar to 20 cm(-1) which is very similar to that of the isolated trimer. This coupling is consistent with the 4.2 K Stokes shift of the fluorescence originating from the 681.5 nm state. An adjacent state at 680.0 nm is assigned. On the basis of the results of Pieper et al. for the isolated trimer, a state at similar to 678.5 nm is inferred. These three lowest energy Q(y)-states are associated with the lowest energy chlorophyll a state of the subunit of the isolated LHC II trimer. Their degeneracy is removed because of structural heterogeneity. The hole-burning results indicate that, aside from a quite uniform and small red shifting, aggregation has little effect on the excitonic level structure and intrinsic dynamics of the isolated trimer, Taken together, the results presented here and in Pieper et al. lead to a model that qualitatively accounts for the strong temperature dependence of aggregation-induced fluorescence quenching between 4.2 and 80 K (Ruban et al. Biochim. Biophys. Acta 1992, 1102, 30). C1 Humboldt Univ, Inst Phys, D-10099 Berlin, Germany. US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Tech Univ Berlin, Max Volmer Inst, D-10623 Berlin, Germany. RP Pieper, J (reprint author), Humboldt Univ, Inst Phys, D-10099 Berlin, Germany. NR 21 TC 20 Z9 20 U1 0 U2 4 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 APR 8 PY 1999 VL 103 IS 14 BP 2422 EP 2428 DI 10.1021/jp983958d PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 188GC UT WOS:000079837600033 ER PT J AU Berg, O Chronister, EL Yamashita, T Scott, GW Sweet, RM Calabrese, J AF Berg, O Chronister, EL Yamashita, T Scott, GW Sweet, RM Calabrese, J TI s-dipentacene: Structure, spectroscopy, and temperature- and pressure-dependent photochemistry SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID EMISSION-SPECTRA; PHOTODIMERIZATION; PENTACENE; DIMERS AB We report the synthesis, characterization, spectroscopy, and photochemistry of s-dipentacene (see Figure 1). The symmetric addition product dimer of pentacene (s-dipentacene) is formed upon irradiation of a solution of pentacene. The structure of s-dipentacene was determined by X-ray crystallography. The crystals had a space group symmetry of P (1) over bar with two molecules per unit cell. One molecule in the unit cell was accompanied by two dichloromethane molecules of solvation. Photodecomposition of s-dipentacene, dispersed in a poly(methyl methacrylate) (PMMA) host matrix, to pentacene was studied. Spectroscopic evidence shows that this photodecomposition proceeds through a trapped intermediate both at low temperature (similar to 12 K) and at room temperature under high pressure (13 kbar). This intermediate is assigned as a "broken dimer" of two pentacene molecules trapped in the PMMA host. We previously reported similar results in the photolysis of both dianthracene and ditetracene at low temperatures, but this is the first report of broken dimer formation at room temperature under high pressure. C1 Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Dupont Co, Wilmington, DE 19880 USA. RP Chronister, EL (reprint author), Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. NR 27 TC 28 Z9 28 U1 0 U2 4 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 APR 8 PY 1999 VL 103 IS 14 BP 2451 EP 2459 DI 10.1021/jp984066g PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 188GC UT WOS:000079837600037 ER PT J AU Howe, SD AF Howe, SD TI Search for a quick getaway from Mars SO NATURE LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Howe, SD (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 1 TC 0 Z9 0 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 APR 8 PY 1999 VL 398 IS 6727 BP 455 EP 455 DI 10.1038/18955 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 185HQ UT WOS:000079662800016 ER PT J AU Ghiorso, A AF Ghiorso, A TI Glenn T. Seaborg (1912-99) - Obituary SO NATURE 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, 1 Cyclotron Rd,Mailstop 71-259, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 8 PY 1999 VL 398 IS 6727 BP 472 EP 472 DI 10.1038/18994 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 185HQ UT WOS:000079662800029 ER PT J AU Ditmire, T Zweiback, J Yanovsky, VP Cowan, TE Hays, G Wharton, KB AF Ditmire, T Zweiback, J Yanovsky, VP Cowan, TE Hays, G Wharton, KB TI Nuclear fusion from explosions of femtosecond laser-heated deuterium clusters SO NATURE LA English DT Article ID X-RAY-EMISSION; ATOMIC CLUSTERS; MULTIPHOTON IONIZATION; NEUTRON-PRODUCTION; COULOMB EXPLOSION; PULSES; IRRADIATION; DYNAMICS; STATES; MATTER AB As a form of matter intermediate between molecules and bulk solids, atomic clusters have been much studied(1). Light-induced processes in dusters can lead to photo-fragmentation(2,3) and Coulombic fission(4), producing atom and ion fragments with a few electron volts (eV) of energy. However, recent studies of the photoionization of atomic dusters with high intensity (>10(16)Wcm(-2)) femtosecond laser pulses have shown that these interactions can be far more energetid(5-13)-excitation of large atomic dusters can produce a superheated microplasma that ejects ions with kinetic energies up to 1 MeV (ref. 10). This phenomenon suggests that through irradiation of deuterium dusters, it would be possible to create plasmas with sufficient average ion energy for substantial nuclear fusion. Here we report the observation of nuclear fusion from the explosions of deuterium clusters heated with a compact, high-repetition-rate table-top laser. We achieve an efficiency of about 10(5) fusion neutrons per joule of incident laser energy, which approaches the efficiency of large-scale laser-driven fusion experiments. Our results should facilitate a range of fusion experiments using: small-scale lasers, and may ultimately lead to the development of a table-top neutron source, which could potentially find wide application in materials studies. C1 Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RP Ditmire, T (reprint author), Univ Calif Lawrence Livermore Natl Lab, Laser Program, L-477, Livermore, CA 94550 USA. RI Yanovsky, Victor/B-5899-2008; Cowan, Thomas/A-8713-2011 OI Cowan, Thomas/0000-0002-5845-000X NR 28 TC 585 Z9 609 U1 9 U2 87 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 8 PY 1999 VL 398 IS 6727 BP 489 EP 492 DI 10.1038/19037 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 185HQ UT WOS:000079662800041 ER PT J AU Egolf, DA Melnikov, IV Springer, RP AF Egolf, DA Melnikov, IV Springer, RP TI Weak nonleptonic Omega(-) decay in chiral perturbation theory SO PHYSICS LETTERS B LA English DT Article ID DECUPLET AB We calculate the weak nonleptonic decay of the Omega(-) baryon to octet final states in heavy baryon chiral perturbation theory (HBChPT). We include the one-loop leading logarithmic effects and show that this improves the universality of the HBChPT constants. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret MSB258, Los Alamos, NM 87545 USA. Cornell Univ, Atom & Solid State Phys Lab, Ithaca, NY 14853 USA. Duke Univ, Dept Phys, Durham, NC 27706 USA. RP Egolf, DA (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret MSB258, Los Alamos, NM 87545 USA. NR 13 TC 4 Z9 4 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 APR 8 PY 1999 VL 451 IS 3-4 BP 267 EP 274 DI 10.1016/S0370-2693(99)00234-8 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 187TW UT WOS:000079805000001 ER PT J AU Decharge, J Berger, JF Dietrich, K Weiss, MS AF Decharge, J Berger, JF Dietrich, K Weiss, MS TI Superheavy and hyperheavy nuclei in the form of bubbles or semi-bubbles SO PHYSICS LETTERS B LA English DT Article DE Hartree-Fock-Bogoliubov; Gogny force; bubble nuclei AB Self-consistent Hartree-Bogoliubov calculations have been performed with the effective interaction of Gogny for a large array of proton and nucleon numbers (120 less than or equal to Z less than or equal to 340; 300 less than or equal to A less than or equal to 1000). Solutions in the form of a bubble and of "unsaturated" nuclei ("semi-bubbles") with a reduced central density are found, which may be ground states or excited metastable configurations. Fission barriers and estimates of a-decay lifetimes are given for typical nuclei. (C) 1999 Elsevier Science B.V. All rights reserved. C1 SPN, DPTA, DIF, CEA, F-91680 Bruyeres Le Chatel, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Tech Univ Munich, D-8046 Garching, Germany. RP Decharge, J (reprint author), SPN, DPTA, DIF, CEA, BP 12, F-91680 Bruyeres Le Chatel, France. NR 14 TC 71 Z9 71 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 APR 8 PY 1999 VL 451 IS 3-4 BP 275 EP 282 DI 10.1016/S0370-2693(99)00225-7 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 187TW UT WOS:000079805000002 ER PT J AU Ji, HF Brown, GM Dabestani, R AF Ji, HF Brown, GM Dabestani, R TI Calix[4]arene-based Cs+ selective optical sensor SO CHEMICAL COMMUNICATIONS LA English DT Article ID ELECTRON-TRANSFER SENSORS; 1,3-ALTERNATE CONFORMATION; AQUEOUS ENVIRONMENT; SOLVENT-EXTRACTION; CESIUM; COMPLEXATION; CATIONS; ETHERS; MEMBRANES; TRANSPORT AB 1,3-Calix[4] bis(9-cyano-10-anthrylmethyl)-o-benzocrown-6 has been synthesized as a first generation caesium selective fluorescent probe, and its emission behavior in the presence of Li+, Na+, K+ and Cs+ ions has been examined. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Dabestani, R (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008,MS-6100, Oak Ridge, TN 37831 USA. NR 29 TC 122 Z9 125 U1 3 U2 11 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 APR 7 PY 1999 IS 7 BP 609 EP 610 DI 10.1039/a808636b PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 184WE UT WOS:000079636100020 ER PT J AU Click, DR Scott, BL Watkin, JG AF Click, DR Scott, BL Watkin, JG TI Highly electrophilic lanthanide complexes containing fluorinated amido ligands: multiple Ln - F interactions, agostic interactions and eta(6)-arene coordination SO CHEMICAL COMMUNICATIONS LA English DT Article ID CHELATING DIAMIDE COMPLEXES; RAY CRYSTAL-STRUCTURE; ALPHA-OLEFINS; POLYMERIZATION; REACTIVITY; DINITROGEN; TITANIUM; BOND; SM AB Highly fluorinated amido ligands have been employed as supporting ligands for homoleptic lanthanide complexes; Xray diffraction studies reveal multiple Ln ... F interactions and a rare example of an eta(6)-bound toluene solvent molecule. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Watkin, JG (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 22 TC 38 Z9 38 U1 0 U2 0 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 APR 7 PY 1999 IS 7 BP 633 EP 634 DI 10.1039/a809275c PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 184WE UT WOS:000079636100032 ER PT J AU Cheng, TY Bullock, RM AF Cheng, TY Bullock, RM TI Isotope effects on hydride transfer reactions from transition metal hydrides to trityl cation. An inverse isotope effect for a hydride transfer SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID STOICHIOMETRIC HYDROGENATION REACTIONS; RADICAL PAIR MECHANISM; NAD+ ANALOGS; CONJUGATED DIENES; ALPHA-CYCLOPROPYLSTYRENE; ELECTROPHILIC REACTIONS; REDUCTIVE ELIMINATION; IONIC HYDROGENATION; OXIDATIVE ADDITION; CARBENIUM IONS AB Hydride transfer from transition metal hydrides (MH) to Ph3C+BF4- gives M-FBF3 and Ph3CH. Deuterium kinetic isotope effects were determined for several MH/MD pairs (CH2Cl2 solution, 25 degrees C). For hydride transfer from Cp*(CO)(3)MoH (Cp* = eta(5)-(CMe5)-Me-5) to substituted trityl cations containing zero, one, two, or three p-MeO groups [Ph-n(p-MeOC6H4)(3-n)C+BF4-; n = 3, 2, 1, 0], the isotope effect remains essentially constant at k(MoH)/k(MoD) = 1.7-1.9 as the rate constant decreases from k(H)- = 6.5 x 10(3) to 1.4 M-1 s(-1). For hydride transfer to Ph3C+BF4- from five metal hydrides [Cp(CO)(3)MoH, Cp*(CO)(3)WH, (indenyl)(CO)(3)WH, Cp"(CO)(3)MoH, and trans-Cp(CO)(2)(PCy3)MoH; Cp = eta(5)-C5H5] With second-order rate constants k(H)- greater than or equal to 3.8 x 10(2) M-1 s(-1), the kinetic isotope effects are also k(MH)/k(MD) = 1.7-1.8. For a series of five tungsten hydrides with substituted Cp ligands, the kinetic isotope effects decrease from k(WH)/k(WD) = 1.8 to 0.47 as the rate constant decreases (from k(H)- = 2.0 x 10(3) to 0.72 M-1 s(-1)). The steadily decreasing values of k(MH)/k(MD), with decreasing rate constants of hydride transfer are interpreted as indicating progressively stronger force constants of isotopically sensitive modes of the transition state, as the reaction slows down in progressing from more electron-donating Cp ligands to less electron-rich Cp ligands. The inverse isotope effect (k(WH)/k(WD) == 0.47) found for the slowest tungsten hydride, (C5H4CO2Me)(CO)(3)WH, is proposed to be due to a product-like transition state for irreversible hydride transfer. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Bullock, RM (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Bullock, R. Morris/L-6802-2016 OI Bullock, R. Morris/0000-0001-6306-4851 NR 61 TC 57 Z9 57 U1 0 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 APR 7 PY 1999 VL 121 IS 13 BP 3150 EP 3155 DI 10.1021/ja983448x PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 187WH UT WOS:000079810800024 ER PT J AU Rustad, JR Dixon, DA Rosso, KM Felmy, AR AF Rustad, JR Dixon, DA Rosso, KM Felmy, AR TI Trivalent ion hydrolysis reactions: A linear free-energy relationship based on density functional electronic structure calculations SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NEUTRON-DIFFRACTION; FORMATION-CONSTANTS; AQUEOUS-SOLUTION; METAL-COMPLEXES; WATER EXCHANGE; HYDRATION; DYNAMICS; STEREOCHEMISTRY; APPROXIMATION; ENERGETICS C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Lab, William R Wiley Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 43 TC 43 Z9 43 U1 4 U2 13 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 APR 7 PY 1999 VL 121 IS 13 BP 3234 EP 3235 DI 10.1021/ja984217t PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 187WH UT WOS:000079810800040 ER PT J AU Goldberg, LA Hart, WE Wilson, DB AF Goldberg, LA Hart, WE Wilson, DB TI Learning foraging thresholds for lizards: an analysis of a simple learning algorithm SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article AB This paper gives proof of convergence for a learning algorithm that describes how anoles (lizards found in the Caribbean) learn foraging threshold distance. An anole will pursue a prey if and only if it is within this threshold of the anole's perch. The learning algorithm was proposed by Roughgarden and his colleagues. They experimentally determined that this algorithm quickly converges to the foraging threshold that is predicted by optimal foraging theory. We provide analytic confirmation that the optimal foraging behavior as predicted by Roughgarden's model can be attained by a lizard that follows this simple and zoologically plausible rule of thumb. (C) 1999 Academic Press. C1 Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. Sandia Natl Labs, Albuquerque, NM 87185 USA. Microsoft Corp, Redmond, WA 98052 USA. RP Goldberg, LA (reprint author), Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. NR 11 TC 3 Z9 3 U1 1 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD APR 7 PY 1999 VL 197 IS 3 BP 361 EP 369 DI 10.1006/jtbi.1998.0877 PG 9 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 181CH UT WOS:000079422700005 ER PT J AU Song, C Klein, M Johnson, B Reynolds, J AF Song, C Klein, M Johnson, B Reynolds, J TI Catalysis in fuel processing and environmental protection. An introduction SO CATALYSIS TODAY LA English DT Editorial Material C1 Penn State Univ, Fuel Sci Program, University Pk, PA 16802 USA. Penn State Univ, Lab Hydrocarbon Proc Chem, University Pk, PA 16802 USA. Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. Phillips Petr Borger Refinery 212, Ctr Tech, Borger, TX 79008 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Song, C (reprint author), Penn State Univ, Fuel Sci Program, University Pk, PA 16802 USA. RI Song, Chunshan/B-3524-2008 OI Song, Chunshan/0000-0003-2344-9911 NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5861 J9 CATAL TODAY JI Catal. Today PD APR 6 PY 1999 VL 50 IS 1 BP 1 EP 1 PG 1 WC Chemistry, Applied; Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 179MG UT WOS:000079330900001 ER PT J AU Wegrzyn, JE Mahajan, D Gurevich, M AF Wegrzyn, JE Mahajan, D Gurevich, M TI Catalytic routes to transportation fuels utilizing natural gas hydrates SO CATALYSIS TODAY LA English DT Article; Proceedings Paper CT Symposium on Catalysis in Fuel Processing and Environmental Protection at the 214th ACS National Meeting CY SEP 07-11, 1997 CL LAS VEGAS, NV SP ACS, ACS Div Petroleum Chem, Fuel Chem, & Environm Chem DE partial oxidation; Fischer-Tropsch diesel; dimethylether; MeOH ID METHANOL AB Gas hydrates hold >50% of earth's total combustible carbon. To make this vast but dilute (CH(4)similar to 3.9 wt%) energy source available, an economical three-step route is outlined. A major technological challenge is environmentally-benign mining of gas hydrates that releases "Aqueous CH4" and makes it available at the surface (Step 1). Step 2 involves a cost-effective partial oxidation (POX) with air route that eliminates the O-2-separation plant (conventional POX with O-2) to produce synthesis gas. In Step 3, technologies that affect catalytic conversion of synthesis gas to Fischer-Tropsch (F-T) diesel, MeOH, and dimethylether (DME) transportation fuels are considered. The selection of MeOH and DME energy liquids is justified based on seven criteria: (1) low temperature; (2) low pressure; (3) high gas conversion per pass to eliminate recycle; (4) high spacetime-yield; (5) high product selectivity; (6) robust catalyst; (7) overall high process efficiency. A Ni/Base catalyst system, presently undergoing pilot testing at Brookhaven National Laboratory (BNL), is described that by virtue of its homogeneous liquid phase operation selectively (>95%) produces methanol with unprecedented single pass conversion (>95%) at T<150 degrees C and P=2-5 MPa essentially satisfies these set-forth process requirements. A preliminary kinetic study on the original BNL catalyst system is presented and a limited kinetic rate expression is deduced. Several areas for further research are identified that will allow economical production of MeOH or DR IE in the skid-mounted unit/flexible product option concept applicable to both on-land and off-short: gas hydrates. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. US DOE, Off Heavy Vehicles Technol, Washington, DC 20585 USA. RP Mahajan, D (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. EM dmahajan@bnl.gov NR 17 TC 13 Z9 13 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5861 J9 CATAL TODAY JI Catal. Today PD APR 6 PY 1999 VL 50 IS 1 BP 97 EP 108 DI 10.1016/S0920-5861(98)00466-0 PG 12 WC Chemistry, Applied; Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 179MG UT WOS:000079330900012 ER PT J AU Wang, J Tian, BM Wang, JY Lu, JM Olsen, C Yarnitzky, C Olsen, K Hammerstrom, D Bennett, W AF Wang, J Tian, BM Wang, JY Lu, JM Olsen, C Yarnitzky, C Olsen, K Hammerstrom, D Bennett, W TI Stripping analysis into the 21st century: faster, smaller, cheaper, simpler and better SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 7th European Conference on ElectroAnalysis (ESEAC 98) CY MAY 24-28, 1998 CL UNIV COIMBRA, COIMBRA, PORTUGAL SP European Soc ElectroAnal Chem, Int Soc Electrochem, Div 3 Anal Electrochem, Portuguese Chem Soc, Div Anal Chem HO UNIV COIMBRA DE stripping analysis; trace metals; environmental sensors; micromachining; microfabrication; remote sensors; hand-held analyzer ID TRACE-METAL CONTAMINANTS; ULTRAMICROELECTRODE ARRAYS; ELECTROCHEMICAL SENSOR; NATURAL-WATERS; ELECTRODES; LEAD; CHEMISTRY; FLOW AB As we approach the 21st century we have been reassessing the way we conduct electrochemical stripping measurements of trace metals. Such rethinking has led to the replacement of conventional stripping protocols and systems with remotely deployed submersible ('lab-on-cable') stripping probes, easy-to-use microfabricated metal-sensor strips or micromachined hand-held total stripping analyzers. Such developments allow one to move the measurements of trace metals to the field, and to perform them more rapidly, reliably and inexpensively. These advances bring significant changes to the monitoring of toxic metals, and allow stripping analysis to retain its place as one of the most powerful tools for trace analysis. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Wang, J (reprint author), New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. EM joewang@nmsu.edu RI Wang, Joseph/C-6175-2011 NR 22 TC 92 Z9 98 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD APR 5 PY 1999 VL 385 IS 1-3 BP 429 EP 435 DI 10.1016/S0003-2670(98)00664-3 PG 7 WC Chemistry, Analytical SC Chemistry GA 183CB UT WOS:000079535500048 ER PT J AU Freund, LB Floro, JA Chason, E AF Freund, LB Floro, JA Chason, E TI Extensions of the Stoney formula for substrate curvature to configurations with thin substrates or large deformations SO APPLIED PHYSICS LETTERS LA English DT Article ID LAYER; FILMS AB Two main assumptions which underlie the Stoney formula relating substrate curvature to mismatch strain in a bonded thin film are that the film is very thin compared to the substrate, and the deformations are infinitesimally small. Expressions for the curvature-strain relationship are derived for cases in which these assumptions are relaxed, thereby providing a basis for interpretation of experimental observations for a broader class of film-substrate configurations. (C) 1999 American Institute of Physics. [S0003-6951(99)04510-6]. C1 Brown Univ, Div Engn, Providence, RI 02912 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Freund, LB (reprint author), Brown Univ, Div Engn, Providence, RI 02912 USA. NR 13 TC 174 Z9 181 U1 2 U2 45 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 APR 5 PY 1999 VL 74 IS 14 BP 1987 EP 1989 DI 10.1063/1.123722 PG 3 WC Physics, Applied SC Physics GA 182DM UT WOS:000079483300019 ER PT J AU Noheda, B Cox, DE Shirane, G Gonzalo, JA Cross, LE Park, SE AF Noheda, B Cox, DE Shirane, G Gonzalo, JA Cross, LE Park, SE TI A monoclinic ferroelectric phase in the Pb(Zr1-xTix)O-3 solid solution SO APPLIED PHYSICS LETTERS LA English DT Article ID ZIRCONATE AB A previously unreported ferroelectric phase has been discovered in a highly homogeneous sample of PbZr0.52Ti0.48O3 by high-resolution synchrotron x-ray powder diffraction measurements. At ambient temperature the sample has tetragonal symmetry (a(t) = 4.037 Angstrom, c(t) = 4.138 Angstrom), and transforms below similar to 250 K into a phase which, unexpectedly, has monoclinic symmetry (a(m) = 5.717 Angstrom, b(m) = 5.703 Angstrom, c(m) = 4.143 Angstrom, beta = 90.53 degrees, at 20 K). The intensity data strongly indicate that the polar axis lies in the monoclinic ac plane close to the pseudocubic [111] direction, which would be an example of the species m3m(12)A2Fm predicted on symmetry grounds by Shuvalov. (C) 1999 American Institute of Physics. [S0003-6951(99)00714-7]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. UAM, Dept Fis Mat, Madrid 28049, Spain. Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. RP Noheda, B (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 13 TC 716 Z9 728 U1 22 U2 154 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 APR 5 PY 1999 VL 74 IS 14 BP 2059 EP 2061 DI 10.1063/1.123756 PG 3 WC Physics, Applied SC Physics GA 182DM UT WOS:000079483300043 ER PT J AU Garde, S Garcia, AE Pratt, LR Hummer, G AF Garde, S Garcia, AE Pratt, LR Hummer, G TI Temperature dependence of the solubility of non-polar gases in water SO BIOPHYSICAL CHEMISTRY LA English DT Article; Proceedings Paper CT CECAM Workshop on Implicit Solvent Models for Biomolecular Simulations CY MAY, 1998 CL CTR CALCUL ATOM & MOLEC, LYON, FRANCE SP Ctr Calcul Atom & Molec HO CTR CALCUL ATOM & MOLEC ID HYDROPHOBIC HYDRATION; ENTROPY; LIQUIDS; PROTEINS; SOLUTES; FORCES AB An explanation is provided for the experimentally observed temperature dependence of the solubility and the solubility minimum of non-polar gases in water. The influence of solute size and solute-water attractive interactions on the solubility minimum temperature is investigated. The transfer of a non-polar solute from the ideal gas into water is divided into two steps: formation of a cavity in water with the size and shape of the solute and insertion of the solute in this cavity which is equivalent to 'turning on' solute-water attractive interactions. This two step process divides the excess chemical potential of the non-polar solute in water into repulsive and attractive contributions, respectively. The reversible work for cavity formation is modeled using an information theory model of hydrophobic hydration. Attractive contributions are calculated by modeling the water structure in the vicinity of non-polar solutes. These models make a direct connection between microscopic quantities and macroscopic observables. Moreover, they provide an understanding of the peculiar temperature dependences of the hydration thermodynamics from properties of pure water; specifically, bulk water density and the water oxygen-oxygen radial distribution function. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Garde, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Garde, Shekhar/C-3060-2008; Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 35 TC 82 Z9 82 U1 1 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 J9 BIOPHYS CHEM JI Biophys. Chem. PD APR 5 PY 1999 VL 78 IS 1-2 BP 21 EP 32 DI 10.1016/S0301-4622(99)00018-6 PG 12 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 191UZ UT WOS:000080041100003 PM 17030303 ER PT J AU Clark, DL Conradson, SD Donohoe, RJ Keogh, DW Morris, DE Palmer, PD Rogers, RD Tait, CD AF Clark, DL Conradson, SD Donohoe, RJ Keogh, DW Morris, DE Palmer, PD Rogers, RD Tait, CD TI Chemical speciation of the uranyl ion under highly alkaline conditions. Synthesis, structures, and oxo ligand exchange dynamics SO INORGANIC CHEMISTRY LA English DT Article ID X-RAY STRUCTURE; AQUEOUS-SOLUTION; O-17 NMR; DIOXOTETRACYANOMETALATE COMPLEXES; ELECTRONIC-STRUCTURE; CARBONATE COMPLEXES; CRYSTAL-STRUCTURES; OXYGEN-EXCHANGE; URANIUM; SPECTROSCOPY AB The tetramethylammonium counterion was used to suppress formation of insoluble uranate salts, M2U2O7, and allow for a detailed structural and spectroscopic characterization of UO2(OH)(n)(2-n) (n = 4, 5) under highly alkaline aqueous solution conditions. Single crystals of [Co(NH3)(6)](2)[UO2(OH)(4)](3). H2O were obtained by cooling a dilute solution of Co(NH3)(6)Cl-3 and UO2(NO3)(2). 6H(2)O in 3.5 M (Me4N)OH to 5 degrees C. The asymmetric unit contains three distinct UO2(OH)(4)(2-) ions, each displaying a pseudo-octahedral coordination geometry with trans oxo ligands. The three independent UO2(OH)(4)(2-) ions in the unit cell give average U=O and U-OH distances of 1.82(1) and 2.26(2) Angstrom, respectively. EXAFS data on solid [Co(NH3)(6)](2)[UO2(OH)(4)](3). H2O and aqueous UO22+ in 3.5 M (Me4N)OH solution were collected at the U L-III edge, and the resulting radial distribution function shows a single asymmetric peak. For the solid and solution, curve fitting reveals two near neighbors. For the crystalline solid, the first shell was fit with two O atoms at a distance of 1.81(1) Angstrom, and the second shell was fit with 3.9(5) O atoms at a distance of 2.21(1) Angstrom. For the solution sample, the first shell contains two O atoms with a U=O distance of 1.79(1) Angstrom, and the second O shell was fit with 5.2(5) O atoms at a U-O distance of 2.22(1) Angstrom. The bond distances for both the solution and solid state samples correspond relatively well with the single-crystal diffraction data; however, the second-shell coordination number is larger in solution than in the solid state, indicating a greater number of OH ligands in solution than in the solid state. Both EXAFS and X-ray diffraction analyses reveal relatively long axial U=O and short equatorial U-OH bonds. Raman spectra of single crystals of [Co(NH3)(6)](2)[UO2(OH)(4)](3). H2O reveal a symmetrical O=U=O stretch at 796 cm(-1), 74 cm(-1) lower than that for the uranyl aquo ion. In solution, the symmetrical O=U=O stretch is at 786 cm(-1), 10 cm(-1) lower than observed in the solid state. O-18 enrichment produces a shift to 752 cm(-1) confirming the assignment in solution. Luminescence spectroscopy recorded as a function of hydroxide ion concentration reveals that an equilibrium exists between two species, assigned to UO2(OH)(4)(2-) and UO2(OH)(5)(3-). The vibronic structure of the luminescence bands was used to determine a vibrational energy of 790 cm(-1) for UO2(OH)(5)(3-) to confirm its assignment. O-17 NMR and O-16/O-18 Raman spectroscopies also reveal an unprecedented facile ligand exchange between U=O and bulk solvent oxygen atoms. Line-broadening analysis of the O-17 NMR data provide activation parameters of Delta H double dagger = 9.8 +/- 0.4 kcal/mol, Delta S double dagger = -18 +/- 6 cal/mol.K, and k(ex)(298K) = 45 +/- 15 s(-1). Crystal data for [Co(NH3)(6)](2)[UO2(OH)(4)](3). H2O: monoclinic space group C2/c, a = 17.4130(4) Angstrom, b = 12.1794(3) Angstrom, c = 15.3721(4) Angstrom, beta = 120.384(1)degrees, Z = 4, R1 = 0.0313, wR2 = 0.0734. C1 Los Alamos Natl Lab, Div Chem Sci & Technol, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, GT Seaborg Inst Transactinium Sci, Los Alamos, NM 87545 USA. Univ Alabama, Dept Chem, Tuscaloosa, AL 35487 USA. RP Clark, DL (reprint author), Los Alamos Natl Lab, Div Chem Sci & Technol, Mail Stop E500, Los Alamos, NM 87545 USA. RI Clark, David/A-9729-2011; Rogers, Robin/C-8265-2013; Morris, David/A-8577-2012 OI Rogers, Robin/0000-0001-9843-7494; NR 53 TC 213 Z9 213 U1 13 U2 82 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 APR 5 PY 1999 VL 38 IS 7 BP 1456 EP 1466 DI 10.1021/ic981137h PG 11 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 184PF UT WOS:000079620400017 ER PT J AU Henson, NJ Hay, PJ Redondo, A AF Henson, NJ Hay, PJ Redondo, A TI Density functional theory studies of the binding of molecular oxygen with Schiff's base complexes of cobalt SO INORGANIC CHEMISTRY LA English DT Article ID MONOMERIC DIOXYGEN ADDUCT; METAL-COMPLEXES; CARRIERS; ACTIVATION; POTENTIALS; RESONANCE; SPECTRA; ATOMS AB Gradient-corrected density functional theory calculations using the B3LYP hybrid functional have been performed on Co(acacen)(pyridine) and Co(salen)(pyridine) complexes and their adducts with molecular oxygen (acacen = 2,11-dihydroxy-4,9-dimethyl-5,8-diaza-2,4,8,10-dodecatetraene, salen = 1,6-bis(2-hydroxyphenyl)-2,5-diaza-1,5-hexadiene). Calculated optimized geometries and dioxygen binding energies show good agreement with experiment. The binding energy for Co(acacen)(pyridine) is calculated to be 53.5 kJ mol(-1) (experiment = 63.1 kJ mol(-1)), and the binding energy for Co(salen)(pyridine) is calculated to be 46.8 kJ mol(-1) (experiment = 51.8 kJ mol(-1)). The calculated O-O distances are in the range 1.28-1.29 Angstrom, which compares to 1.26 Angstrom from crystal structure data for Co(acacen)(pyridine)(O-2). Model complexes for Co(acacen)(pyridine) are also examined, and ligand substitution effects correlated with the computed Co-O distance. The calculated O-O vibrational frequency (1243 cm(-1)) is slightly higher than typical experimental frequencies while the calculated Co-O frequency is 439 cm(-1). The effect of basis set variation on the computed binding energy in the model complexes was also examined, and it was found that a more flexible basis set was required when using standard effective core potentials for cobalt. In addition, the inclusion of basis set superposition error and the zero point correction were found to severely reduce the magnitude of the calculated binding energy. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Henson, NJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 47 TC 71 Z9 71 U1 2 U2 16 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 APR 5 PY 1999 VL 38 IS 7 BP 1618 EP 1626 DI 10.1021/ic9813056 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 184PF UT WOS:000079620400040 ER PT J AU Lin, ZW Vogt, R AF Lin, ZW Vogt, R TI Energy loss effects on heavy quark production in heavy-ion collisions at root s=5.5 A TeV SO NUCLEAR PHYSICS B LA English DT Article DE ultrarelativistic heavy-ion collisions; parton energy loss ID GLUON PLASMA; QCD; PHYSICS; NUCLEI; DECAY AB We study the effect of energy loss on charm and bottom quarks in high-energy heavy-ion collisions including hadronization, longitudinal expansion and partial thermalization. We consider in detail the detector geometry and single lepton energy cuts of the ALICE and CMS detectors at the Large Hadron Collider (LHC) to show the large suppression of high p(T) heavy quarks and the consequences on their semileptonic decays, (C) 1999 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 31 TC 41 Z9 41 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 5 PY 1999 VL 544 IS 1-2 BP 339 EP 354 DI 10.1016/S0550-3213(98)00833-5 PG 16 WC Physics, Particles & Fields SC Physics GA 178YF UT WOS:000079296200012 ER PT J AU Antunes, ND Bettencourt, LMA Zurek, WH AF Antunes, ND Bettencourt, LMA Zurek, WH TI Vortex string formation in a 3D U(1) temperature quench SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCALAR FIELD-THEORY; COSMOLOGICAL EXPERIMENTS; SUPERFLUID HE-3; LIQUID-CRYSTALS; SYMMETRY BREAKS; COSMIC STRINGS; DYNAMICS; DENSITY; SYSTEM; ANALOG AB We report the first large scale numerical study of the dynamics of a second order phase transition caused by a gradual decrease of temperature in a U(1) lambda phi(4) theory in three spatial dimensions. We present a detailed account of the dynamics of the fields and focus on vortex string formation as a function of the quench rate. The results are found in good agreement with the theory of defect formation proposed by Kibble and Zurek. [S0031-9007(99)08817-1]. C1 Univ Geneva, Dept Phys Theor, CH-1211 Geneva 4, Switzerland. Univ Calif Los Alamos Natl Lab, Theoret Div MS B288, Los Alamos, NM 87545 USA. RP Antunes, ND (reprint author), Univ Geneva, Dept Phys Theor, 24 Quai E Ansermet, CH-1211 Geneva 4, Switzerland. NR 22 TC 94 Z9 94 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 APR 5 PY 1999 VL 82 IS 14 BP 2824 EP 2827 DI 10.1103/PhysRevLett.82.2824 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800004 ER PT J AU Chatterjee, R Hallock, GA Wootton, AJ AF Chatterjee, R Hallock, GA Wootton, AJ TI Observation of multiple modes of interior density turbulence in the TEXT-U tokamak SO PHYSICAL REVIEW LETTERS LA English DT Article ID ION BEAM PROBE; CONTRAST IMAGING-SYSTEM; FLUCTUATION MEASUREMENTS; SPECTRUM; TRANSPORT AB Two distinct broadband modes of density turbulence propagating in the electron drift direction are simultaneously observed in the first complete measurement of the wave number frequency spectrum S(k,omega) in the interior of the TEXT-U tokamak plasma. A drift wave-type mode with a peak in the wave number spectrum at k(theta) similar to 4.5 cm(-1) is found on both sides of the magnetic axis. A long-wavelength mode with k(theta) less than or equal to 2 cm(-1) is found only on the low field side of the tokamak. The results resolve apparent discrepancies in previous turbulence measurements Confinement properties of TEXT-Lr an consistent with the transport predicted by the observed drift wave-type (k) over bar(theta) = 3 cm(-1) [S0031-9007(99)08765-7]. C1 Univ Texas, Fus Res Ctr, Austin, TX 78712 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Chatterjee, R (reprint author), Univ Texas, Fus Res Ctr, Austin, TX 78712 USA. NR 21 TC 2 Z9 2 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 APR 5 PY 1999 VL 82 IS 14 BP 2876 EP 2879 DI 10.1103/PhysRevLett.82.2876 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800017 ER PT J AU Barrena, E Kopta, S Ogletree, DF Charych, DH Salmeron, M AF Barrena, E Kopta, S Ogletree, DF Charych, DH Salmeron, M TI Relationship between friction and molecular structure: Alkylsilane lubricant films under pressure SO PHYSICAL REVIEW LETTERS LA English DT Article ID ATOMIC-FORCE MICROSCOPY; SELF-ASSEMBLED MONOLAYER; CHAIN-LENGTH DEPENDENCE; MICA; ALKANETHIOLS; AGGREGATION; GOLD AB We demonstrate that energy losses during friction of alkylsilane self-assembled monolayers with sharp atomic force microscope tips can be correlated to molecular events occurring at specific threshold loads. Under these lends, discrete molecular tilts occur, which are dictated by the geometrical requirements of the close packing of molecules. The barriers overcome during these tilt events give rise to discrete changes in the frictional forces. [S0031-9007(99)05798-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Barrena, Esther/B-7683-2014; Ogletree, D Frank/D-9833-2016 OI Barrena, Esther/0000-0001-9163-2959; Ogletree, D Frank/0000-0002-8159-0182 NR 20 TC 126 Z9 126 U1 1 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 APR 5 PY 1999 VL 82 IS 14 BP 2880 EP 2883 DI 10.1103/PhysRevLett.82.2880 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800018 ER PT J AU Jach, T Zhang, Y Colella, R de Boissieu, M Boudard, M Goldman, AI Lograsso, TA Delaney, DW Kycia, S AF Jach, T Zhang, Y Colella, R de Boissieu, M Boudard, M Goldman, AI Lograsso, TA Delaney, DW Kycia, S TI Dynamical diffraction and x-ray standing waves from atomic planes normal to a twofold symmetry axis of the quasicrystal AlPdMn SO PHYSICAL REVIEW LETTERS LA English DT Article ID AL-PD-MN; SURFACE-STRUCTURE DETERMINATION; QUASI-CRYSTALS; ICOSAHEDRAL PHASE; ALLOYS; ORDER AB We have observed dynamical diffraction in the [0240 (2) over bar 4] and [0460 (4) over bar 6] reflections of the icosahedral quasicrystal AlPdMn in the back-reflection geometry (theta(B) = 90 degrees). The x-ray fluorescence From the A1 and Pd atoms exhibits strong standing wave behavior, similar to that observed in crystalline materials. The data indicate a long-range order of each species of atoms, with the coherent positions attributable to distributions of the Al and Pd, which we compare to a centrosymmetric model. We observe deviations from the model which imply small departures from inversion symmetry along the twofold symmetry axis and from the expected coherent fractions for Al. [S0031-9007(99)08910-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. ENSEEG, LTPCM, F-38402 St Martin Dheres, France. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Cornell Univ, CHESS, Ithaca, NY 14853 USA. RP Jach, T (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 18 Z9 18 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 APR 5 PY 1999 VL 82 IS 14 BP 2904 EP 2907 DI 10.1103/PhysRevLett.82.2904 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800024 ER PT J AU Robertson, JL Ice, GE Sparks, CJ Jiang, X Zschack, P Bley, F Lefebvre, S Bessiere, M AF Robertson, JL Ice, GE Sparks, CJ Jiang, X Zschack, P Bley, F Lefebvre, S Bessiere, M TI Local atomic arrangements in Fe63.2Ni36.8 invar from diffuse X-ray scattering measurements SO PHYSICAL REVIEW LETTERS LA English DT Article ID FE-NI-INVAR; ALLOYS; IRON; ANTIFERROMAGNETISM; ORDER AB X-ray measurements show that Fe63.2Ni36.8 has a slight tendency toward L1(0) and/or L1(2) ordering with a preference for weakly ordered {100} platelets. This bias for Fe-Ni first neighbor pairs decreases the number of Fe atoms with eight or more Fe nearest neighbors. Such Fe rich regions are strongly correlated to the alloy's Invar properties. The mean separation of Fe-Fe first neighbor pairs is expanded relative to the average lattice, and the amount of expansion increases upon cooling from 293 to 60 K. This expansion supports the large moment-large volume explanation for the Invar effect. [S0031-9007(99)08748-7]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. ENSEEG, LTPCM, F-38042 St Martin Dheres, France. Univ Paris Sud, LURE, F-91405 Orsay, France. RP Robertson, JL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 41 TC 36 Z9 36 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 5 PY 1999 VL 82 IS 14 BP 2911 EP 2914 DI 10.1103/PhysRevLett.82.2911 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800026 ER PT J AU Gurevich, AV Zybin, KP Roussel-Dupre, RA AF Gurevich, AV Zybin, KP Roussel-Dupre, RA TI Lightning initiation by simultaneous effect of runaway breakdown and cosmic ray showers SO PHYSICS LETTERS A LA English DT Article ID AIR-BREAKDOWN; X-RAYS; THUNDERSTORM; ELECTRONS AB The combined action of cosmic ray showers (CRS) and runaway breakdown (RB) on thunderstorm atmosphere is studied. The ionization of atmosphere produced by CRS core being strongly amplified in RB conditions is shown to be sufficient to generate a highly ionized plasma region. Electric polarization of this plasma region is manifested in a significant local amplification of a thunderstorm electric field, what could result in a local electric breakdown and lead to initiation of lightning. Experiments which could check the predictions of the theory are proposed. (C) 1999 Published by Elsevier Science B.V. C1 Russian Acad Sci, PN Lebedev Phys Inst, Moscow 117924, Russia. Univ Calif Los Alamos Natl Lab, Space & Sci Technol Div, Los Alamos, NM 87545 USA. RP Gurevich, AV (reprint author), Russian Acad Sci, PN Lebedev Phys Inst, Moscow 117924, Russia. RI Zybin, Kirill/K-8619-2015; Gurevich, Aleksandr/K-8668-2015 OI Gurevich, Aleksandr/0000-0003-1125-9774 NR 19 TC 99 Z9 106 U1 1 U2 7 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 APR 5 PY 1999 VL 254 IS 1-2 BP 79 EP 87 DI 10.1016/S0375-9601(99)00091-2 PG 9 WC Physics, Multidisciplinary SC Physics GA 183LP UT WOS:000079555300012 ER PT J AU Liang, L Feng, XD Liu, J Rieke, PC AF Liang, L Feng, XD Liu, J Rieke, PC TI Preparation of composite-crosslinked poly(N-isopropylacrylamide) gel layer and characteristics of reverse hydrophilic-hydrophobic surface SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE polymer gel; poly(N-isopropylacrylamide); dynamic contact angle; organosilane; surface; temperature-sensitive polymers ID INTERPENETRATING POLYMER NETWORKS; CRITICAL SOLUTION TEMPERATURE; N-ISOPROPYLACRYLAMIDE; COPOLYMERS; MEMBRANES; HYDROGELS; PLASMA; UNITS; CHAIN AB The composite-crosslinked poly(N-isopropylacrylamide) (PNIPAAm) gels were prepared by grafting N-isopropylacrylamide on the surface of glass plates modified by organosilanes. The glass plates as the substrate increase the mechanical strength of composite PNIPAAm gel layers. We investigated the effects of a series of organosilanes and the reaction time of organosilanes on surface characteristics, such as the static contact angle and the layer thickness. We discuss the equilibrium swelling ratio and the water release behavior of the gel layers in terms of the crosslinking density of the composite gels. The composite gels exhibit not only the characteristics of remarkable water release but also the reversed hydrophilic-hydrophobic surface properties. The gel layers are hydrophilic under 25 degrees C and change to hydrophobic above 40 degrees C. (C) 1999 John Wiley & Sons, Inc. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liang, L (reprint author), Pacific NW Natl Lab, 902 Battelle Blvd,POB 999,Mail Stop P8-37, Richland, WA 99352 USA. NR 39 TC 30 Z9 30 U1 1 U2 6 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD APR 4 PY 1999 VL 72 IS 1 BP 1 EP 11 DI 10.1002/(SICI)1097-4628(19990404)72:1<1::AID-APP1>3.0.CO;2-B PG 11 WC Polymer Science SC Polymer Science GA 168PX UT WOS:000078702400001 ER PT J AU Veenstra, TD AF Veenstra, TD TI Electrospray ionization mass spectrometry: A promising new technique in the study of protein/DNA noncovalent complexes SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article DE electrospray ionization mass spectrometry; DNA; protein; noncovalent ID DNA-BINDING DOMAIN; GEL-ELECTROPHORESIS; GENE-5 PROTEIN; TRANSCRIPTION; RECEPTOR; BACTERIOPHAGE-M13; FLUORESCENCE; REPRESSOR AB With the emergence of electrospray ionization mass spectrometry (ESI-MS), mass spectrometry is no longer restricted to the study of small, stable molecules, but has become a viable technique to study large biomolecules as well as noncovalent biomolecular complexes. ESI-RIS has been used to study noncovalent interactions involving proteins with metals, ligands, peptides, oligonucleotides, and other proteins. An area where ESI-MS holds significant promise is in the study of protein/DNA interactions. The most common technique employed to study protein/DNA interactions is the electrophoretic gel mobility shift assay (EMSA). Although this technique has and will continue to provide excellent results, ESI-MS has shown the ability to provide detailed results not easily obtainable by EMSA. In this review I will discuss some of the protein/DNA noncovalent interactions that have been measured using ESI-MS, and contrast the results obtained by ESI-MS to those obtained by ERISA. (C) 1999 Academic Press. C1 Pacific NW Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Veenstra, TD (reprint author), Pacific NW Lab, Environm & Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 21 TC 46 Z9 46 U1 2 U2 11 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD APR 2 PY 1999 VL 257 IS 1 BP 1 EP 5 DI 10.1006/bbrc.1998.0103 PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 184MC UT WOS:000079615100001 PM 10092500 ER PT J AU Gutowski, M Skurski, P AF Gutowski, M Skurski, P TI Theoretical study of the quadrupole-bound anion (BeO)(-)(2) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID FRANCK-CONDON PRINCIPLE; GROUND-STATE; PHOTOELECTRON-SPECTROSCOPY; VIBRONIC TRANSITIONS; POLYATOMIC-MOLECULES; ELECTRONIC-STRUCTURE; DYNAMICAL SYMMETRY; (HF)(2)(-); AFFINITIES; CS2 AB The global minimum on the potential energy surface of (BeO)(2)(-) calculated at the coupled-cluster level of theory with single, double, and non-iterative triple excitations, corresponds to a rhombic D-2h structure, which may be considered as a quadrupole-bound anion. The rhombic isomer is separated by a C-s symmetry transition state from the linear isomer and the energy barrier amounts to 15.4 kcal/mol. The energies of the D-2h and C-infinity v anionic isomers differ by 6.2 kcal/mol. The vertical electron detachment energies amount to 8903 and 23847 cm(-1) (1.10 and 2.96 eV) for the rhombic and linear anion, respectively. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Mat Resources, Richland, WA 99352 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Gutowski, M (reprint author), Pacific NW Natl Lab, Mat Resources, Richland, WA 99352 USA. NR 28 TC 20 Z9 20 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 APR 2 PY 1999 VL 303 IS 1-2 BP 65 EP 75 DI 10.1016/S0009-2614(99)00172-4 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 182YN UT WOS:000079525900010 ER PT J AU Ali, MA Butcher, RJ Bryan, JC AF Ali, MA Butcher, RJ Bryan, JC TI Synthetic, spectroscopic and X-ray crystallographic structural studies on some copper(II) complexes of the 6-methylpyridine-2-carboxaldehyde Schiff base of S-methyldithiocarbazate SO INORGANICA CHIMICA ACTA LA English DT Article DE crystal structures; copper complexes; Schiff base complexes; dithiocarbazate complexes ID CRYSTAL-STRUCTURE; 2-FORMYLPYRIDINE THIOSEMICARBAZONE; BIOLOGICAL-ACTIVITIES; NICKEL(II) COMPLEXES; CADMIUM(II) COMPLEXES; LIGANDS; 2-ACETYLPYRIDINE; ZINC(II); ACID; HL AB The complexes, [Cu(NNS)CH3COO] and [Cu(NNS)(2)] (HNNS = the 6-methylpyridine-2-carboxaldehyde Schiff base of S-methyldithiocarbazate) have been synthesized and characterized by a variety of physico-chemical techniques. The crystal structures of these complexes have also been determined by X-ray diffraction studies. The mono-ligated acetato complex has a square-planar structure with the copper(II) ion lying in an approximate plane of four coordinating atoms, three of which are supplied by the Schiff base and the fourth is provided by an oxygen of the anion. The bis-ligand copper(II) complex, [Cu(NNS)(2)] has a distorted octahedral structure in which the Schiff bases are bound to the copper(II) ion as NNS tridentate ligands coordinating via the pyridine nitrogen atom, the azomethine nitrogen atom and the thiolato sulfur atom. The ligands are arranged meridionally around the copper(II) ion. Infrared and electronic spectral data for both complexes are consistent with their structures. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Brunei Darussalam, Dept Chem, BSB-2028 Brunei, Brunei. Howard Univ, Dept Chem, Washington, DC 20059 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Ali, MA (reprint author), Univ Brunei Darussalam, Dept Chem, BSB-2028 Brunei, Brunei. NR 24 TC 23 Z9 23 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD APR 2 PY 1999 VL 287 IS 1 BP 8 EP 13 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 185EG UT WOS:000079654700002 ER PT J AU Stroschein, SL Wang, W Luo, KX AF Stroschein, SL Wang, W Luo, KX TI Cooperative binding of Smad proteins to two adjacent DNA elements in the plasminogen activator inhibitor-1 promoter mediates transforming growth factor beta-induced Smad-dependent transcriptional activation SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID TUMOR-SUPPRESSOR SMAD4; DPC4 GENE; SIGNAL-TRANSDUCTION; INDUCIBLE ELEMENTS; II RECEPTOR; CELLS; EXPRESSION; COMPLEX; MADR2; PHOSPHORYLATION AB Transforming growth factor beta (TGF beta) activates transcription of the plasminogen activator inhibitor type-1 (PAI-1) gene through a major TGF beta-responsive region (-740 and -647) in the PAI-1 promoter. This process requires the Smad family of signaling molecules. Upon phosphorylation by the TGF beta receptors, Smad2 and Smad3 homoligomerize and heteroligomerize with Smad4, translocate to the nucleus and activate transcription of TGF beta responsive genes. Smad3 and Smad4 have been shown to bind to various sites in the PAI-1 promoter. To determine the number of Smad-binding sites within the 94-base pair major TGF beta-responsive region and the mechanism of Smad-mediated transactivation, we systematically mapped the Smad-binding sites and show that Smad4 and Smad3 bind cooperatively to two adjacent DNA elements in this region. Both elements were required for TGF beta-induced, Smad3- and Smad4-dependent activation of PAI-1 transcription. Contrary to previous reports, transactivation of the PAI-1 promoter was mediated by the amino- but not carboxyl-terminal domains of the Smads. Furthermore, oligomerization of Smad3 markedly enhanced its binding to the two binding sites, Finally, a Smad4 mutation identified in a human pancreatic carcinoma that inactivates Smad4 signaling abolished Smad4: DNA binding activity, hence preventing transactivation of TGF beta-responsive genes. These results underscore the importance of the Smad4 DNA binding activity in controlling cell growth and carcinogenesis. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Sci & Technol China, Dept Biol, Hefei, Anhui, Peoples R China. RP Luo, KX (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, 229 Stanley Hall,Mail Code 3206, Berkeley, CA 94720 USA. NR 49 TC 104 Z9 112 U1 0 U2 2 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 APR 2 PY 1999 VL 274 IS 14 BP 9431 EP 9441 DI 10.1074/jbc.274.14.9431 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 181PX UT WOS:000079451800043 PM 10092624 ER PT J AU Grossmann, JG Hasnain, SS Yousafzai, FK Smith, BE Eady, RR Schindelin, H Kisker, C Howard, JB Tsuruta, H Muller, J Rees, DC AF Grossmann, JG Hasnain, SS Yousafzai, FK Smith, BE Eady, RR Schindelin, H Kisker, C Howard, JB Tsuruta, H Muller, J Rees, DC TI Comparing crystallographic and solution structures of nitrogenase complexes SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Editorial Material ID TRANSITION-STATE COMPLEX; X-RAY-SCATTERING; AZOTOBACTER-VINELANDII; IRON PROTEIN C1 CLRC, Daresbury Lab, Synchrotron Radiat Dept, Warrington WA4 4AD, Cheshire, England. John Innes Ctr, Nitrogen Fixat lab, Norwich NR4 7UH, Norfolk, England. CALTECH, Div Chem & Chem Engn, Howard Hughes Med Inst, Pasadena, CA 91125 USA. Univ Minnesota, Dept Biochem, Minneapolis, MN 55455 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Max Delbruck Ctr Mol Med, D-13092 Berlin, Germany. RP Hasnain, SS (reprint author), CLRC, Daresbury Lab, Synchrotron Radiat Dept, Warrington WA4 4AD, Cheshire, England. NR 13 TC 12 Z9 12 U1 0 U2 1 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 APR PY 1999 VL 55 BP 727 EP 728 DI 10.1107/S0907444999003856 PN 4 PG 2 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 188NW UT WOS:000079855200001 PM 10336305 ER PT J AU Terwilliger, TC Berendzen, J AF Terwilliger, TC Berendzen, J TI Automated MAD and MIR structure solution SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID ELECTRON-DENSITY MAPS; X-RAY-DIFFRACTION; ISOMORPHOUS REPLACEMENT; PROTEIN; ERRORS; CRYSTALLOGRAPHY; LOCATION; GENOMICS AB Obtaining an electron-density map from X-ray diffraction data can be difficult and time-consuming even after the data have been collected, largely because MIR and MAD structure determinations currently require many subjective evaluations of the qualities of trial heavy-atom partial structures before a correct heavy-atom solution is obtained. A set of criteria for evaluating the quality of heavy-atom partial solutions in macromolecular crystallography have been developed. These have allowed the conversion of the crystal structure-solution process into an optimization problem and have allowed its automation. The SOLVE software has been used to solve MAD data sets with as many as 52 selenium sites in the asymmetric unit. The automated structure-solution process developed is a major step towards the fully automated structure-determination, model-building and procedure which is needed for genomic scale determinations. C1 Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Terwilliger, TC (reprint author), Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Mail Stop M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 37 TC 3129 Z9 3150 U1 7 U2 48 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 APR PY 1999 VL 55 BP 849 EP 861 DI 10.1107/S0907444999000839 PN 4 PG 13 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 188NW UT WOS:000079855200017 PM 10089316 ER PT J AU Gill, HS Pfluegl, GMU Eisenberg, D AF Gill, HS Pfluegl, GMU Eisenberg, D TI Preliminary crystallographic studies on glutamine synthetase from Mycobacterium tuberculosis SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article AB The etiologic agent of tuberculosis, Mycobacterium tuberculosis, has been shown to secrete the enzyme glutamine synthetase (TB-GS) which is apparently essential for infection. Four crystal forms of a recombinant TB-GS were grown. The one chosen for synchrotron X-ray data collection belongs to space group P2(1)2(1)2(1) with unit-cell dimensions 208 x 258 x 274 Angstrom, yielding 2.4 Angstrom resolution data. A Matthews number of 2.89 Angstrom(3) Da(-1) is found, corresponding to 24 subunits of molecular mass 1300 kDa in the asymmetric unit. From earlier work, the structure of Salmonella typhimurium GS, which is 51% identical in sequence to TB-GS, is known to be dodecameric with 622 symmetry. Self-rotation calculations on the TB-GS X-ray data reveal only one set of sixfold and twofold axes of symmetry. A Patterson map calculated from the native X-ray data confirms that there are two dodecamers in the asymmetric unit, having both their sixfold and twofold axes parallel to one another. C1 Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Dept Chem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Dept Biochem & Biol Chem, Los Angeles, CA 90095 USA. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Dept Chem, Box 951570, Los Angeles, CA 90095 USA. NR 15 TC 5 Z9 5 U1 0 U2 0 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 APR PY 1999 VL 55 BP 865 EP 868 DI 10.1107/S0907444998017685 PN 4 PG 4 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 188NW UT WOS:000079855200019 PM 10089318 ER PT J AU Hwang, KY Cho, CS Kim, SS Baek, K Kim, SH Yu, YG Cho, YJ AF Hwang, KY Cho, CS Kim, SS Baek, K Kim, SH Yu, YG Cho, YJ TI Crystallization and preliminary X-ray analysis of glutamate racemase from Aquifex pyrophilus, a hyperthermophilic bacterium SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID MANDELATE RACEMASE; CATALYTIC RESIDUES; ASPARTATE RACEMASE; ALANINE RACEMASE; DIFFRACTION DATA; MECHANISM; IDENTIFICATION; RESOLUTION; CLONING; GENE AB Glutamate racemase catalyzes the reversible reaction of L-glutamate to D-glutamate, an essential component of the bacterial cell wall. Glutamate racemase from Aquifex pyrophilus has been crystallized by the hanging-drop vapor-diffusion method using polyethylene glycol 6000 as a precipitant. The crystals belong to space group P6(1)22 or P6(5)22 with unit-cell parameters a = b = 72.1, c = 185.02 Angstrom. The asymmetric unit contains one molecule, corresponding to a V-m value of 2.35 Angstrom(3) Da(-1). Complete data sets from a native and a mercury-derivative crystal have been collected at 2.0 and 2.3 Angstrom resolution, respectively, using a synchrotron-radiation source. C1 Korea Inst Sci & Technol, Struct Biol Ctr, Seoul, South Korea. Korea Univ, Dept Genet Engn, Seoul 136701, South Korea. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Cho, YJ (reprint author), Korea Inst Sci & Technol, Struct Biol Ctr, POB 131, Seoul, South Korea. NR 17 TC 3 Z9 3 U1 0 U2 0 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 APR PY 1999 VL 55 BP 927 EP 928 DI 10.1107/S0907444999000608 PN 4 PG 2 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 188NW UT WOS:000079855200038 PM 10089337 ER PT J AU Gschneidner, KA AF Gschneidner, KA TI Cerium transformations SO ADVANCED MATERIALS & PROCESSES LA English DT Letter C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Gschneidner, KA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD APR PY 1999 VL 155 IS 4 BP 73 EP 73 PG 1 WC Materials Science, Multidisciplinary SC Materials Science GA 184DZ UT WOS:000079596200014 ER PT J AU Ghosal, S AF Ghosal, S TI Mathematical and physical constraints on large-eddy simulation of turbulence SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 29th Fluid Dynamics Conference CY JUN 15-18, 1998 CL ALBUQUERQUE, NEW MEXICO SP AIAA ID SUBGRID-SCALE MODEL; NUMERICAL ERRORS; MIXING LAYER; FLOWS; REALIZABILITY; INVARIANCE; SCHEMES; TERMS AB Recent progress in the theoretical foundations of large-eddy simulation is reviewed. Most of the work reported is motivated by conceptual difficulties encountered in applying the large eddy simulation method to inhomogeneous complex geometry flows. Among the topics covered are the problem of the lack of commutation between filtering and derivative operators for inhomogeneous flows, the issues of enforcing symmetry and realizability conditions in subgrid modeling, and the problem of unacceptably high numerical errors in large eddy simulation implementations with finite difference methods. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ghosal, S (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Ghosal, Sandip/A-3534-2009; Ghosal, Sandip/B-7595-2009 OI Ghosal, Sandip/0000-0001-6587-3716; NR 33 TC 63 Z9 63 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 1999 VL 37 IS 4 BP 425 EP 433 DI 10.2514/2.752 PG 9 WC Engineering, Aerospace SC Engineering GA 180YH UT WOS:000079413100003 ER PT J AU Miller, RM Smith, CI Jastrow, JD Bever, JD AF Miller, RM Smith, CI Jastrow, JD Bever, JD TI Mycorrhizal status of the genus Carex (Cyperaceae) SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE arbuscular fungi; Carex; Cyperaceae; mycorrhizae; mycotrophy; root hairs ID VESICULAR-ARBUSCULAR MYCORRHIZAE; VEGETATION SYSTEMS; VASCULAR PLANTS; ASSOCIATIONS; ECOSYSTEMS; PHOSPHORUS; INFECTION; ISLAND; CANADA; ORIGIN AB The Cyperaceae have generally been considered nonmycorrhizal, although recent evidence suggests that mycotrophy may be considerably more widespread among sedges than was previously realized. This study surveyed 23 species of Carer occurring in upland and wetland habitats in northeastern Illinois. Mycorrhizal infection by arbuscular fungi was found in the roots of 16 species of Carer and appears to occur in response to many factors, both environmental and phylogenetic. While some species appear to be obligately nonmycorrhizal, edaphic influences may be responsible for infection in others. In five of the seven Carer species that were nonmycorrhizal, a novel root character, the presence of bulbous-based root hairs, was identified. The taxonomically patchy distribution of the distinctive root hair trait suggests that these structures may have evolved several times within the genus. Evidence of multiple independent origins of the root hair trait lends support to the hypothesis that root hairs represent an adaptation to nonmycotrophy. Although taxonomic position does seem to be of importance in determining the mycorrhizal dependence of sedges, the pattern may be a patchwork of both mycorrhizal clades and clades that have adapted to the nonmycorrhizal state. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Univ Chicago, Dept Ecol & Evolut Biol, Chicago, IL 60637 USA. RP Miller, RM (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 47 TC 68 Z9 75 U1 4 U2 19 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY 1735 NEIL AVE, COLUMBUS, OH 43210 USA SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD APR PY 1999 VL 86 IS 4 BP 547 EP 553 DI 10.2307/2656816 PG 7 WC Plant Sciences SC Plant Sciences GA 187NH UT WOS:000079792500012 PM 10205075 ER PT J AU Reed, W Jagust, W Al-Mateen, M Vichinsky, E AF Reed, W Jagust, W Al-Mateen, M Vichinsky, E TI Role of positron emission tomography in determining the extent of CNS ischemia in patients with sickle cell disease SO AMERICAN JOURNAL OF HEMATOLOGY LA English DT Article DE sickle cell disease; positron emission tomography; stroke; cerebrovascular disease; magnetic resonance imaging; magnetic resonance angiography ID STROKE; CHILDREN; MR; ABNORMALITIES AB Nearly 25% of patients with sickle cell disease (SCD) experience central nervous system morbidity involving both large and small vessel disease. Optimal imaging methods for determining the extent of ischemia are not known. Positron emission tomography (PET) has the unique ability to show tissue function as well as structure. Reports concerning patients with non-SCD neurodegenerative disorders suggest PET may be useful in determining prognosis. We compared magnetic resonance imaging, magnetic resonance angiography, and neuropsychological testing with PET prospectively. Six patients with SCD and a history of stroke, aged 10 to 28, were enrolled. PET studies were performed on an ECAT HR 47 scanner (Siemens/CTI, Knoxville, TN) using 18-F-fluorodeoxyglucose as a tracer. PET interpretations were conducted in blinded fashion. MRI studies found two patients with only small vessel disease and four with both large and small vessel disease. In two of four subjects with large vessel disease, PET showed a corresponding metabolic abnormality and also identified an area of hypometabolism extending beyond the anatomical lesion as shown by MRI. PET did not demonstrate an abnormality corresponding with small vessel disease. Detailed neuropsychological testing demonstrated cognitive dysfunction in all cases. For some patients, PET may add sensitivity in detecting impaired metabolism in the area surrounding a major vessel infarct. However, the technique does not appear to be generally useful in characterizing smalt watershed or deep white matter infarcts. Larger studies, to include control subjects and carefully selected un-transfused SCD patients, are needed. A combination of conventional imaging and neuropsychological testing remains the preferred evaluation for most SCD patients with neurologic symptoms. Am. J. Hematol. 60:268-272, 1999. 1999 Wiley-Liss,Inc. C1 Childrens Hosp Oakland, Ctr Med, Dept Hematol Oncol, Oakland, CA 94609 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Irwin Ctr, Blood Ctr Pacific, San Francisco, CA USA. Mary Bridge Childrens Hosp, Dept Neurol, Tacoma, WA USA. RP Vichinsky, E (reprint author), Childrens Hosp Oakland, Ctr Med, Dept Hematol Oncol, 747 52nd St, Oakland, CA 94609 USA. FU NHLBI NIH HHS [HL-20985] NR 15 TC 26 Z9 26 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0361-8609 J9 AM J HEMATOL JI Am. J. Hematol. PD APR PY 1999 VL 60 IS 4 BP 268 EP 272 DI 10.1002/(SICI)1096-8652(199904)60:4<268::AID-AJH3>3.0.CO;2-C PG 5 WC Hematology SC Hematology GA 182NK UT WOS:000079504900003 PM 10203099 ER PT J AU Solomon, A Weiss, DT Schell, M Hrncic, R Murphy, CL Wall, J McGavin, MD Pan, HJ Kabalka, GW Paulus, MJ AF Solomon, A Weiss, DT Schell, M Hrncic, R Murphy, CL Wall, J McGavin, MD Pan, HJ Kabalka, GW Paulus, MJ TI Transgenic mouse model of AA amyloidosis SO AMERICAN JOURNAL OF PATHOLOGY LA English DT Article ID INTERLEUKIN-6; MICE; PROTEIN; AMYLOIDOGENESIS; PATHOGENESIS AB AA amyloidosis can be induced in mice experimentally through injection of certain chemical or biological compounds. However, the usefulness of this approach is limited by its dependence on exogenous inflammatory agents that stimulate cytokines to increase the synthesis of precursor serum amyloid A (SAA) protein and the transitory nature of the pathological fibrillar deposits. We now report that transgenic mice carrying the human interleukin 6 gene under the control of the metallothionein-I promoter had markedly increased concentrations of SAA and developed amyloid in the spleen, liver, and kidneys by 3 months of age. At the time of death about 6 months later, organs obtained from these animals had extensive amyloid deposits. This disease process was apparent radiographically using small-animal computer axial tomography and magnetic resonance imaging equipment. The AA nature of the amyloid was evidenced immunohistochemically and was unequivocally established by sequence analysis of protein extracted from the fibrils. The availability of this unique in vivo experimental model of AA amyloidosis provides the means to assess the therapeutic efficacy of agents designed to reduce or prevent the fibrillar deposits found in AA and other types of amyloid-associated disease. C1 Univ Tennessee, Med Ctr, Dept Med, Knoxville, TN 37920 USA. Univ Tennessee, Med Ctr, Human Immunol & Canc Program, Knoxville, TN 37920 USA. Univ Tennessee, Med Ctr, Grad Sch Med, Dept Radiol, Knoxville, TN 37920 USA. Univ Tennessee, Coll Vet Med, Dept Pathol, Knoxville, TN 37920 USA. Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37831 USA. RP Solomon, A (reprint author), Univ Tennessee, Med Ctr, Dept Med, 1924 Alcoa Highway, Knoxville, TN 37920 USA. EM asolomon@MC.UTMCK.edu FU NCI NIH HHS [R01 CA010056, CA 10056] NR 29 TC 49 Z9 49 U1 0 U2 1 PU AMER SOC INVESTIGATIVE PATHOLOGY, INC PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202-3993 USA SN 0002-9440 J9 AM J PATHOL JI Am. J. Pathol. PD APR PY 1999 VL 154 IS 4 BP 1267 EP 1272 DI 10.1016/S0002-9440(10)65378-3 PG 6 WC Pathology SC Pathology GA 184MU UT WOS:000079616600034 PM 10233864 ER PT J AU Kohn, MJ AF Kohn, MJ TI Why most "dry" rocks should cool "wet" SO AMERICAN MINERALOGIST LA English DT Article ID OXYGEN-ISOTOPE FRACTIONATIONS; METAMORPHIC ROCKS; WATER FUGACITY; SELF-DIFFUSION; STABLE ISOTOPE; QUARTZ; TEMPERATURE; DIOPSIDE; MINERALS; HYDROGEN AB A new consideration of oxygen isotope resetting among metamorphic minerals is made accounting for (1) the possibility of f(H2O)-buffering by typical mineral assemblages during cooling and (2) experimental data that show that high f(H2O) correlates with high diffusion rates. Isotope closure temperatures in buffered rocks are intermediate between simpler predictions based on "wet" (1 kbar hydrothermal) and "dry" (P less than or equal to 1 atm, H2O-absent) diffusion experiments, but are typically within similar to 50 degrees C of closure temperature estimates that use "wet" diffusion rates, yet 200-300 degrees C different from "dry." Even though many rocks may be "dry" in that they lack a hydrous fluid that is physically present during cooling, buffering of f(H2O) results in quasi-"wet" diffusion rates. Re-evaluation of published data shows that most rocks indeed exhibit substantial isotope resetting that is best matched by predictions of f(H2O)-buffering models. Wet- and dry-diffusion models somewhat overestimate and greatly underestimate resetting respectively. Previous interpretations invoking "dry" diffusion rates may derive from erroneous fractionation factors or faster cooling rates than assumed, The rare preservation of isotope closure temperatures that are higher than predicted may reflect faster than expected cooling rates or extraordinarily low f(H2O) in conjunction with anhydrous assemblages. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kohn, MJ (reprint author), Univ S Carolina, Dept Geol Sci, Columbia, SC 29208 USA. RI Kohn, Matthew/A-2562-2012 NR 77 TC 21 Z9 22 U1 0 U2 3 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 APR PY 1999 VL 84 IS 4 BP 570 EP 580 PG 11 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 184UC UT WOS:000079631300011 ER PT J AU Biino, GG Mannella, N Kay, A Mun, BJ Fadley, CS AF Biino, GG Mannella, N Kay, A Mun, BJ Fadley, CS TI Surface chemical characterization and surface diffraction effects of real margarite (001): An angle-resolved XPS investigation SO AMERICAN MINERALOGIST LA English DT Article ID RAY PHOTOELECTRON-SPECTROSCOPY; ATOMIC-FORCE MICROSCOPY; ELECTRON-DIFFRACTION; ENERGY; AUGER; SCATTERING; MUSCOVITE; MINERALS; MICAS AB The (001) surface of natural pure margarite was chemically characterized by angle-resolved Xray photoelectron spectroscopy (ARXPS). The extreme surface sensitivity of ARXPS permits concluding that the chemical composition of the near-surface region differs from the bulk because of the strong anisotropy of the margarite structure. Depth profiling was carried out by angle resolved spectroscopy that is a non destructive measuring technique. More grazing polar angles sample increasingly superficial layers of the margarite. The topmost layers are made up of C, due to the mineral/atmosphere interaction. At low grazing angles the concentration of Si increases, and both Al and Ca decreases; therefore we conclude that the tetrahedral sheet is the topmost monolayer. Repulsion between the octahedral and tetrahedral sheets is probably responsible for the cleavage. Photoelectron diffraction effects are also clearly evidenced by Si, Ca, and Al. Single-scattering cluster calculations were performed in simulating scanned angle core emission. The calculated patterns do not show a reasonable agreement with experimental data. C1 Asylum Adv Earth Sci, CH-3086 Zimmerwald, Switzerland. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Biino, GG (reprint author), Asylum Adv Earth Sci, Pavillon, CH-3086 Zimmerwald, Switzerland. EM ggbiino@access.ch NR 46 TC 3 Z9 3 U1 0 U2 3 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 APR PY 1999 VL 84 IS 4 BP 629 EP 638 PG 10 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 184UC UT WOS:000079631300016 ER PT J AU Dunbar, J Takala, S Barns, SM Davis, JA Kuske, CR AF Dunbar, J Takala, S Barns, SM Davis, JA Kuske, CR TI Levels of bacterial community diversity in four arid soils compared by cultivation and 16S rRNA gene cloning SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID RIBOSOMAL-RNA GENES; GRADIENT GEL-ELECTROPHORESIS; POLYMERASE CHAIN-REACTION; MICROBIAL DIVERSITY; PCR AMPLIFICATION; PHYLOGENETIC DIVERSITY; DNA FRAGMENTS; BACTERIOPLANKTON; POPULATIONS; ENVIRONMENT AB Techniques based on amplification of 16S rRNA genes for comparing bacterial communities are now widely used in microbial ecology, but calibration of these techniques with traditional tools, such as cultivation, has been conspicuously absent. In this study, we compared levels of bacterial community diversity in two pinyon rhizosphere soil samples and two between-tree (interspace) soil samples by analyzing 179 cultivated bacterial isolates and 801 16S rRNA genes amplified from extracted soil DIVA, Phylotypes were defined by performing a restriction fragment length polymorphism analysis of 16S rRNA gene sequences with the enzymes RsaI and BstUI. The average level of 16S rRNA gene sequence similarity of members of a phylotype was 86.6% based on an an analysis of partial sequences. A total of 498 phylotypes were identified among the 16S ribosomal DNA (rDNA) clones, while 34 phylotypes occurred among the cultivated isolates. Analysis of sequences from a subset of the phylotypes showed that at least seven bacterial divisions were represented in the clone libraries, whereas the isolates represented only three. The phylotype richness, frequency distribution (evenness), and composition of the four culture collections and the four clone libraries were investigated by using a variety of diversity indices. Although cultivation and 16S rRNA cloning analyses gave contradictory descriptions of the relative phylotype richness for one of the four environments, the two methods identified qualitatively consistent relationships when levels of evenness were compared. The levels of phylotype similarity between communities were uniformly low (15 to 31%). Both methods consistently indicated that one environment was distinct from the other three. Our data illustrate that while 16S rDNA cloning and cultivation generally describe similar relationships between soil microbial communities, significant discrepancies can occur. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Environm Mol Biol Grp, Los Alamos, NM 87545 USA. RP Kuske, CR (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Environm Mol Biol Grp, M888, Los Alamos, NM 87545 USA. NR 51 TC 314 Z9 331 U1 4 U2 46 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 APR PY 1999 VL 65 IS 4 BP 1662 EP 1669 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 183AE UT WOS:000079530000043 PM 10103265 ER PT J AU Barns, SM Takala, SL Kuske, CR AF Barns, SM Takala, SL Kuske, CR TI Wide distribution and diversity of members of the bacterial kingdom Acidobacterium in the environment SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID RIBOSOMAL-RNA SEQUENCES; MOLECULAR MICROBIAL DIVERSITY; SOIL; DNA; COMMUNITY; MICROORGANISMS; EXTRACTION; SAMPLE; FIELD; VIEW AB To assess the distribution and diversity of members of the recently identified bacterial kingdom Acidobacterium, members of this kingdom present in 43 environmental samples were surveyed by PCR amplification. A primer designed to amplify rRNA gene sequences (ribosomal DNAs [rDNAs]) from most known members of the kingdom was used to interrogate bulk DNA extracted from the samples. Positive PCR results were obtained with all temperate soil and sediment samples tested, as well as some hot spring samples, indicating that members of this kingdom are very widespread in terrestrial environments. PCR primers specific for four phylogenetic subgroups within the kingdom were used in similar surveys. All four subgroups were detected in most neutral soils and some sediments, while only two of the groups were seen in most low-pH environments. The combined use of these primers allowed identification of a novel lineage within the kingdom in a hot spring environment. Phylogenetic analysis of rDNA sequences from our survey and the literature outlines at least six major subgroups within the kingdom. Taken together, these data suggest that members of the Acidobacterium kingdom are as genetically and metabolically diverse, environmentally widespread and perhaps as ecologically important as the well-known Proteobacteria and gram-positive bacterial kingdoms. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Environm Mol Biol Grp, Los Alamos, NM 87545 USA. RP Barns, SM (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Environm Mol Biol Grp, M888, Los Alamos, NM 87545 USA. NR 43 TC 244 Z9 261 U1 5 U2 30 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 APR PY 1999 VL 65 IS 4 BP 1731 EP 1737 PG 7 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 183AE UT WOS:000079530000052 PM 10103274 ER PT J AU Haegel, NM Simoes, JC White, AM Beeman, JW AF Haegel, NM Simoes, JC White, AM Beeman, JW TI Transient behavior of infrared photoconductors: application of a numerical model SO APPLIED OPTICS LA English DT Article ID GERMANIUM PHOTOCONDUCTORS; EXTRINSIC PHOTOCONDUCTORS AB A numerical model for the transient response of extrinsic photoconductors is applied to the behavior of Ge:Ga and GaAs:Te detectors. Photoconductors display a two-component response to changes in illumination. The characteristic time and magnitude for the slow component have been studied as a function of background flux, applied field, temperature, device length, and signal size. For large-signal applications, the background flux affects the transient response even when the signal is orders of magnitude greater than the background. Experimental results are presented to support key predictions of the modeling. Because the ratio of fast to slow components is independent of both background and signal size, we propose the operation of detectors in such a way that final signal levels are derived from the fast component. (C) 1999 Optical Society of America. C1 Fairfield Univ, Dept Phys, Fairfield, CT 06430 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Def Res Agcy, Malvern WR14 3PS, Worcs, England. RP Haegel, NM (reprint author), Fairfield Univ, Dept Phys, Fairfield, CT 06430 USA. EM nhaegel@fair1.fairfield.edu NR 16 TC 21 Z9 21 U1 0 U2 2 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 APR 1 PY 1999 VL 38 IS 10 BP 1910 EP 1919 DI 10.1364/AO.38.001910 PG 10 WC Optics SC Optics GA 184TU UT WOS:000079630200002 PM 18319745 ER PT J AU Sathyam, US Colston, BW Da Silva, LB Everett, MJ AF Sathyam, US Colston, BW Da Silva, LB Everett, MJ TI Evaluation of optical coherence quantitation of analytes in turbid media by use of two wavelengths SO APPLIED OPTICS LA English DT Article ID TIME-RESOLVED REFLECTANCE; BIREFRINGENCE CHARACTERIZATION; BIOLOGICAL TISSUE; SCATTERING MEDIA; TOMOGRAPHY; TRANSMITTANCE; REFLECTOMETRY; SPECTROSCOPY; INDEX AB We introduce a novel method for determining analyte concentration as a function of depth in a highly scattering media by use of a dual-wavelength optical coherence tomography system. We account for the effect of scattering on the measured attenuation by using a second wavelength that is not absorbed by the sample. We assess the applicability of this technique by measuring the concentration of water in an Intralipid phantom, using a probe wavelength of 1.53 mu m and a reference wavelength of 1.31 mu m. The results of our study show a strong correlation between the measured absorption and the water content of the sample. The accuracy of the technique, however, was limited by the dominance of scattering over absorption in the turbid media. Thus, although the effects of scattering were minimized, significant errors remained in the calculated absorption values. More-accurate results could be obtained with the use of more powerful superluminescent diodes and a choice of wavelengths at which absorption effects are more significant relative to scattering. (C) 1999 Optical Society of America. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Sathyam, US (reprint author), Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA. EM ujwal@llnl.gov NR 27 TC 29 Z9 31 U1 0 U2 1 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 APR 1 PY 1999 VL 38 IS 10 BP 2097 EP 2104 DI 10.1364/AO.38.002097 PG 8 WC Optics SC Optics GA 184TU UT WOS:000079630200027 PM 18319770 ER PT J AU Farrow, RL Rakestraw, DJ AF Farrow, RL Rakestraw, DJ TI Analysis of degenerate four-wave mixing spectra of NO in a CH4/N-2/O-2 flame SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID TRANSITION DIPOLE-MOMENT; OXY-ACETYLENE FLAME; 4-WAVE-MIXING SPECTROSCOPY; TEMPERATURE DETERMINATION; RELATIVE POPULATIONS; LINE STRENGTHS; NITRIC-OXIDE; FIELD LIMIT; OH; DEPENDENCE AB We report comparisons of degenerate four-wave mixing (DFWM) spectra of NO measured in a CH4/N-2/O-2 flame to spectral simulations based on a two-level theory for stationary, saturable absorbers by Abrams et al. Temperatures determined from least-squares fits of simulations to experimental spectra in the A(2)Sigma(+) <-- X(2)Pi(+) (0, 0) band are compared to temperatures obtained from OH absorption spectroscopy and a radiation-corrected thermocouple. We find that DFWM rotational temperatures derived from e-branch spectra agree with thermocouple and are independent of pump laser intensity for low to moderate saturation (I approximate to I-sat). However, the temperatures are systematically low and depend on pump intensity if the analysis neglects saturation effects. We demonstrate a method for obtaining an effective pump saturation intensity for use with the two-level model. This approach for analyzing saturated DFWM line intensities differs from previous work in that the use of the theory of Abrams et al. rather than a transition-dipole-moment power law allows treatment of a much wider range of saturation. Based on the observed signal-to-noise ratio an NO detection sensitivity of 25 ppm is projected, limited by a DFWM background interference specific to hydrocarbon flames. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA. RP Farrow, RL (reprint author), Sandia Natl Labs, Combust Res Facil, POB 969, Livermore, CA 94550 USA. NR 31 TC 6 Z9 7 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD APR PY 1999 VL 68 IS 4 BP 741 EP 747 DI 10.1007/s003400050697 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA 181HB UT WOS:000079434500016 ER PT J AU Carroll, J Lerche, I Abraham, JD Cisar, DJ AF Carroll, J Lerche, I Abraham, JD Cisar, DJ TI Sediment ages and flux variations from depth profiles of Pb-210: lake and marine examples SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID WATER EXCHANGE PROCESSES; BASIN; RATES AB Sediment accumulation rates are redetermined for several freshwater and marine settings to demonstrate the application of a new methodology for interpreting sediment core profiles of radioisotope activity versus depth. Depositional histories were reconstructed using the sediment isotope tomography (SIT) methodology, which abandons the stringent requirement of current methods that sediment accumulation rates and isotopic fluxes may not both vary with time. Using inverse numerical analysis techniques in conjunction with a predictive model, the SIT method is able to separate the effects of sediment accumulation from flux variations to determine age-to-depth relationships. Cumulative probability procedures provide a framework for interpreting the sensitivity and accuracy of the model-determined age-to-depth relationships. Restrictions applied to previous methods on interpreting sediment profiles affected by mixing must also be adhered to when using the SIT method. Previously published data from two Estonian lakes, Kurtna and Nommejarv, from Rockwell Reservoir in Northeastern Ohio and from Cape Lookout Eight, NC, are examined to demonstrate the broad applicability of the methodology. With the exception of one location, the resultant age-to-depth relationships determined by the model agree with earlier interpretations. In the Estonian Lake Nommejarv, previous use of the Constant Flux model overestimates sediment ages for two known time horizons, giving ages of 43 yr at 22 cm and 111 yr at 45 cm. The age-to-depth relationship determined by the SIT method reproduces satisfactorily the time horizons of 16+/- 1 yr at 22 cm and 35 +/- 2 yr at 45 cm, in agreement with the onset of industrial activities in the region. These examples illustrate the suitability of this new methodology for application in a variety of complex depositional environments. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Akvaplan Niva AS, N-9005 Tromso, Norway. Univ S Carolina, Dept Geol Sci, Columbia, SC 29208 USA. Colorado Sch Mines, Dept Geophys, Golden, CO 80401 USA. RUST Geotech Inc, US DOE, Grand Junct Projects Off, Grand Junction, CO 81502 USA. RP Carroll, J (reprint author), Akvaplan Niva AS, Fiolveien 15, N-9005 Tromso, Norway. NR 17 TC 15 Z9 17 U1 0 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD APR PY 1999 VL 50 IS 4 BP 793 EP 804 DI 10.1016/S0969-8043(98)00099-2 PG 12 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 172PM UT WOS:000078933100021 ER PT J AU Han, L Niemczyk, TM Haaland, DM Lopez, GP AF Han, L Niemczyk, TM Haaland, DM Lopez, GP TI Enhancing IR detection limits for trace polar organics in aqueous solutions with surface-modified sol-gel-coated ATR sensors SO APPLIED SPECTROSCOPY LA English DT Article DE waveguide sensor; infrared spectroscopy; sol-gel film; partial least-squares ID CHALCOGENIDE GLASS-FIBERS; CHLORINATED HYDROCARBONS; ABSORPTION SENSOR; SPECTROSCOPY; MEMBRANES; ELEMENTS; WATER AB An experimental investigation into the use of surface-modified solgel-coated Si attenuated total reflectance (ATR) mid-infrared sensors was completed to determine the detection limits for trace amounts of polar organic molecules in aqueous solutions. The surfaces of porous sol-gel films were modified to be mostly hydrophobic in order to concentrate the polar organic analytes in the film while largely excluding the water solvent. This modification of the Si ATR sensor coupled with multivariate partial least-squares calibration methods allowed approximately three orders of magnitude improvement in detection limits for acetone when compared to detection limits from univariate analysis of spectra obtained on uncoated Si ATR sensors. The comparable improvement for isopropanol in aqueous solution was over two orders of magnitude, Studies performed on mixtures of acetone and isopropanol in water confirmed that quantitative analyses could be performed on these mixture systems with cross-validated standard errors of prediction (CVSEP) of 0.5 and 8.7 ppm, respectively. Using three times the CVSEP as an estimate of the detection limit translates to detection limits of 1.5 and 26 ppm for acetone and isopropanol, respectively. C1 Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. RP Niemczyk, TM (reprint author), Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. NR 27 TC 20 Z9 20 U1 2 U2 6 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1999 VL 53 IS 4 BP 381 EP 389 DI 10.1366/0003702991946839 PG 9 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 187PQ UT WOS:000079795900003 ER PT J AU Haaland, DM Han, L Niemczyk, TM AF Haaland, DM Han, L Niemczyk, TM TI Use of CLS to understand PLS IR calibration for trace detection of organic molecules in water SO APPLIED SPECTROSCOPY LA English DT Article DE multivariate calibration; classical least-squares; partial least-squares; principal component analysis; infrared waveguide sensors ID LEAST-SQUARES METHODS; QUANTITATIVE SPECTRAL-ANALYSIS; MULTIVARIATE CALIBRATION AB Partial least-squares (PLS) and principal component regression (PCR) methods applied to spectral data can generally provide excellent quantitative analysis precision, but extraction of qualitative spectral interpretation from the models can be more difficult. For example, we have achieved sensitivity in the parts-per-million range for polar organic compounds in aqueous solutions using infrared (IR) spectroscopy and modified sol-gef-coated ATR sensors. The interpretation of PLS or PCR loading vectors obtained from calibrations involving orthogonally designed solutions of acetone and isopropanol in water yields a misleading understanding of the mechanism for the IR detection of isopropanol on these sensors. Examination of the Loading vectors from PLS or PCR or the first weight-loading vector from the PLS model would suggest that the spectral calibration is based largely on the interaction of the isopl propanol with the surface modifier of the sol-gel coating. However, a classical least-squares (CLS) analysis of the data show s clearly that this interaction is not a significant source of the spectral calibration, but rather the calibration is primarily due to the spectroscopic signal of the isopropanol analyte. In this case, the misleading qualitative interpretation of the PLS and PCR models is the result of the spectral variation being dominated by the effects of spectrometer drift. CLS can overcome this problem if a parameter is included in the CLS calibration that adequately represents the drift. In the example presented here, time of spectral data collection is an appropriate drift-related parameter that can be added to the CLS calibration concentration model in order to provide the qualitative information needed to correctly interpret the spectral data. Other methods to include the effects of spectrometer drift in the CLS model are also presented. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Haaland, DM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 12 TC 20 Z9 20 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 APR PY 1999 VL 53 IS 4 BP 390 EP 395 DI 10.1366/0003702991946848 PG 6 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 187PQ UT WOS:000079795900004 ER PT J AU Wu, JL Egan, WJ Milanovich, FP Myrick, ML AF Wu, JL Egan, WJ Milanovich, FP Myrick, ML TI Analysis of metal salts by combining spectral windows: Quantifying and optimizing cost-effectiveness of multispectral analyses SO APPLIED SPECTROSCOPY LA English DT Article DE fluorescence; Raman; multispectral; cluster analysis AB Luminescence and Raman measurements of metal (Er3+, Tb3+, Sm3+, EU3+, UO22+ and Na+) nitrates from multiple spectral windows are combined and analyzed to determine whether this multispectral approach provides any benefit over the best single-measurement, single-window technique by itself, The individual measurements we combined were obtained under the following conditions (1) excited at 488 nm and detected from 500 to 730 nm, (2) excited at 514.5 nm and detected from 530 to 700 nm, and (3) excited at 785 nm and detected from 800 nm to 920 nm, The first two conditions were excellent for producing fluorescence, while the latter was best for Raman spectroscopy because it avoided most fluorescence. Single-window measurements, particularly the near-infrared Raman spectroscopy of the nitrate counterions, were sufficiently similar to make visual identification of the metal salts from the spectra impossible, The combined data set provided easy visual differentiation between the metal salts. However, we found that hierarchical cluster analysis of the single-window measurements could also be used to identify the metal nitrates even when only the Raman spectral windows of the nitrates were studied, To select,windows for a multispectral approach rationally, we define an efficacy parameter, IIT for each possible combination of measurement windows, plus a formula for cost estimation for the multispectral system. This parameter is evaluated for the data presented in the paper, with the conclusion that the least costly acceptable combination consists of only two windows with the same excitation source. In cases such as these, pooled multispectral analysis is proposed as an excellent means of selecting the appropriate technique and wavelength range for an optimal single measurement set, but subsets of the pooled data may function equally well or even better for specific monitoring tasks, especially when cost analysis is necessary. Means of optimizing costs are described briefly, as are means of performing the efficacy calculation when analyses are not of equal importance. C1 Univ S Carolina, Dept Biochem & Chem, Columbia, SC 29208 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Myrick, ML (reprint author), Univ S Carolina, Dept Biochem & Chem, Columbia, SC 29208 USA. OI Myrick, Michael/0000-0002-6905-0925 NR 11 TC 1 Z9 1 U1 0 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1999 VL 53 IS 4 BP 439 EP 447 DI 10.1366/0003702991946721 PG 9 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 187PQ UT WOS:000079795900010 ER PT J AU Maeda, T Lee, JW Shul, RJ Han, J Hong, J Lambers, ES Pearton, SJ Abernathy, CR Hobson, WS AF Maeda, T Lee, JW Shul, RJ Han, J Hong, J Lambers, ES Pearton, SJ Abernathy, CR Hobson, WS TI Inductively coupled plasma etching of III-V semiconductors in BCl3-based chemistries I. GaAs, GaN, GaP, GaSb and AlGaAs SO APPLIED SURFACE SCIENCE LA English DT Article DE inductively coupled plasma etching; BCl3; semiconductor ID INP; CL-2/AR; BCL3; ALN AB BCl3, with addition of N-2. Ar or H-2. is found to provide smooth anisotropic pattern transfer in GaAs, GaN. GaP, GaSb and AlGaAs under Inductively Coupled Plasma (ICP) conditions. Maxima in the etch rates fur these materials are observed at 33% N-2 or 87% H-2 (by flow) addition to BCl3, whereas Ar addition does nut show tills behavior, Maximum etch rates are typically much higher for GaAs, GaP, GaSb and AlGaAs (similar to 1.2 mu m/min) than for GaN(similar to 0.3 mu m/min) due to the higher bund energies of the latter. The rates decrease at higher pressure, saturate with source Fewer (ion nux) and tend to show maxima with chuck power (ion energy). The etched surfaces remain stoichiometric over a broad range of plasma conditions. (C) 1999 Elsevier Science B.V, All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Plasma Therm, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Maeda, T (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 26 TC 38 Z9 39 U1 3 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD APR PY 1999 VL 143 IS 1-4 BP 174 EP 182 DI 10.1016/S0169-4332(98)00594-7 PG 9 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 192JB UT WOS:000080074200022 ER PT J AU Maeda, T Lee, JW Shul, RJ Han, J Hong, J Lambers, ES Pearton, SJ Abernathy, CR Hobson, WS AF Maeda, T Lee, JW Shul, RJ Han, J Hong, J Lambers, ES Pearton, SJ Abernathy, CR Hobson, WS TI Inductively coupled plasma etching of III-V semiconductors in BCl3-based chemistries - II. InP, InGaAs, InGaAsP, InAs and AlInAs SO APPLIED SURFACE SCIENCE LA English DT Article DE inductively coupled plasma etching; BCl3; semiconductors ID ELECTRON-CYCLOTRON-RESONANCE; GAAS; CL-2/AR; CH4/H2/AR; DAMAGE; GASB; GAP AB A parametric study of etch rates and surface morphologies of Ln-containing compound semiconductors (InP, InGaAs, InGaAsP, InAs and AlInAs) obtained by BCl3-based Inductively Coupled Plasmas (ICP) is reported. Etch rates in the range 1500-3000 Angstrom/min are obtained for all the materials at moderate source powers (500 W), with the rates being a strong function of discharge composition, rf chuck power and pressure. Typical root-mean-square surface roughness of similar to 5 nm were obtained for InP, which is worse than the values obtained for Ga-based materials under the same conditions(similar to 1 nm). The near surface of etched samples is typically slightly deficient in the group V element, but the depth of this deficiency is small (a few tens of angstroms). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Fujitsu Labs Ltd, Kanagawa, Japan. Plasma Therm, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Maeda, T (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 25 TC 9 Z9 12 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD APR PY 1999 VL 143 IS 1-4 BP 183 EP 190 DI 10.1016/S0169-4332(98)00593-5 PG 8 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 192JB UT WOS:000080074200023 ER PT J AU Zijlstra, AA Minniti, D AF Zijlstra, AA Minniti, D TI A dwarf irregular galaxy at the edge of the local group: Stellar populations and distance of IC5152 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (IC 5152, IRAS 21594-51, ESO 237-27); galaxies : irregular; galaxies : stellar content; galaxy : formation; Local Group ID GIANT BRANCH STARS; GALACTIC GLOBULAR-CLUSTERS; OXYGEN ABUNDANCES; MAGELLANIC-CLOUDS; REFERENCE-CATALOG; VELOCITY-FIELD; CARBON STARS; MILKY-WAY; LUMINOSITY; PHOTOMETRY AB We have obtained V- and I-band photometry for about 700 stars in the field of the dwarf irregular galaxy IC 5152, previously considered a possible member of the Local Group. Deep VI color-magnitude diagrams are presented of the main body of this galaxy and of a nearby field. We infer a distance by comparison with the VI color-magnitude diagrams of similar galaxies and with theoretical isochrones. The distance modulus to IC 5152 is found to be m - M-o = 26.15 +/- 0.2, adopting E(V - I) = 0. This distance of D = 1.7 Mpc implies that IC 5152 is not a certain member of the Local Group. We also construct a deep optical luminosity function. By comparison with theoretical isochrones, we find a metallicity Z approximate to 0.002, which is lower than previous estimates. Using this metallicity and distance, IC 5152 now fits the metallicity-luminosity relation for dwarf galaxies. The youngest stars in the held studied have an age of similar to 10(7) Gyr, and there is a substantial population of stars with log t > 7.8-8 yr. The central region of IC 5152 is an active site of star formation, as found by comparing our optical photometry with Hubble Space Telescope ultraviolet images. Several candidate globular clusters are found, as well as a candidate for a potential nucleus. C1 UMIST, Dept Phys, Manchester M60 1QD, Lancs, England. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Pontificia Univ Catolica Chile, Dept Astron, Dept Astron & Astrophys, Santiago 22, Chile. RP Zijlstra, AA (reprint author), UMIST, Dept Phys, POB 88, Manchester M60 1QD, Lancs, England. NR 59 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1999 VL 117 IS 4 BP 1743 EP 1757 DI 10.1086/300802 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 194ZK UT WOS:000080224500010 ER PT J AU Revnivtsev, M Borozdin, K Emelyanov, A AF Revnivtsev, M Borozdin, K Emelyanov, A TI Timing analysis of the X-ray transient source XTE J1806-246 (2S1803-245) SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE stars : binaries : general; stars : flare; stars : neutron; stars : individual : XTE J1806-246; X-rays : stars ID POWER SPECTRA; BINARIES AB An outburst of the X-ray transient source XTE J1806-246 (2S1803-245) was observed by the Rossi X-ray Timing Explorer from April-July 1998. Strong quasi-periodical oscillations (QPO) with a central peak frequency around 9 Hz was detected in one observation of the series performed by the PCA/RXTE experiment. The X-ray flux from the source during the observation with QPO was maximal. The energy spectrum of XTE J1806-246 at this time was softer than for other observations. Statistically significant variability of the QPO parameters was detected, in short-term correlation with the flux variability. Fractional amplitudes of Very Low frequency Noise and the QPO component of the power density spectrum demonstrate a strong energy dependence, while other parameters do not change significantly. C1 Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. Max Planck Inst Astrophys, D-85740 Garching, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Revnivtsev, M (reprint author), Russian Acad Sci, Space Res Inst, Profsoyuznaya 84-32, Moscow 117810, Russia. EM revnivtsev@hea.iki.rssi.ru NR 15 TC 13 Z9 13 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 APR PY 1999 VL 344 IS 2 BP L25 EP L28 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 189DL UT WOS:000079888800004 ER PT J AU Luppino, GA Gioia, IM Hammer, F LeFevre, O Annis, JA AF Luppino, GA Gioia, IM Hammer, F LeFevre, O Annis, JA TI A search for gravitational lensing in 38 X-ray selected clusters of galaxies SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Review DE galaxies : clusters : general; gravitational lensing; X-rays : galaxies; cosmology : observations : dark matter ID MEDIUM-SENSITIVITY SURVEY; GIANT LUMINOUS ARCS; FAINT BLUE GALAXIES; REDSHIFT SURVEY CATALOGS; DISTANT FIELD GALAXIES; DARK-MATTER; SPECTROSCOPIC SURVEY; MASS-DISTRIBUTION; RICH CLUSTERS; BACKGROUND GALAXIES AB We present the results of a CCD imaging survey for gravitational lensing in a sample of 38 X-ray-selected clusters of galaxies. Our sample consists of the most X-ray luminous (L(x) greater than or equal to 2 10(44) ergs-l) clusters selected from the Einstein, Observatory Extended Medium Sensitivity Survey (EMSS) that are observable from Mauna Kea (delta > -40 degrees). The sample spans a redshift range of 0.15 less than or equal to z less than or equal to 0.823 and includes 5 clusters with z > 0.5. CCD images of the clusters were obtained in excellent seeing. There is evidence of strong gravitational lensing in the form of giant arcs (length l greater than or equal to 8 ", axis ratio l/w greater than or equal to 10) in 8 of the 38 clusters. Two additional clusters contain shorter arclets, and 6 more clusters contain candidate arcs that require follow-up observations to confirm their lensing origin. Since the survey does not have a uniform surface brightness limit we do not draw any conclusion based on the statistics of the arcs found. We note, however, that 60% (3 of 5) of the clusters with L(x) > 10(45) ergs(-1), and none of the 15 clusters with L(x) < 4 1044 ergs(-1) contain giant arcs, thereby confirming that high X-ray luminosity does identify the most massive systems, and thus X-ray selection is the preferred method for finding true, rich clusters at intermediate and high redshifts. The observed geometry of the arcs, most of which are thin, have large axis ratios (l/w >10), and are aligned orthogonal to the optical major axes of the clusters, indicate the cluster core mass density profiles must be compact (steeper than isothermal). In several cases, however, there is also some evidence, in the form of possible radial arcs, for density profiles with finite core radii. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CNR, Ist Radioastron, I-40129 Bologna, Italy. DAEC, Observ Meudon, F-92176 Meudon, France. Astron Spatiale Lab, F-13376 Marseille 12, France. Fermilab Natl Accelerator Lab, Expt Astrophys Grp, Batavia, IL 60510 USA. RP Gioia, IM (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM gioia@ira.bo.cnr.it RI Le Fevre, Olivier/G-7389-2011; Gioia, Isabella/B-6982-2012 OI Gioia, Isabella/0000-0003-3127-498X NR 115 TC 82 Z9 83 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 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD APR PY 1999 VL 136 IS 1 BP 117 EP 137 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 183KZ UT WOS:000079553900014 ER PT J AU Brotherton, MS Gregg, MD Becker, RH Laurent-Muehleisen, SA White, RL Stanford, SA AF Brotherton, MS Gregg, MD Becker, RH Laurent-Muehleisen, SA White, RL Stanford, SA TI Discovery of a radio-loud/radio-quiet binary quasar SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : interactions; quasars : emission lines; quasars : general ID COMPACT STEEP-SPECTRUM; SKY SURVEY; GALAXIES AB We report the discovery of a small-separation quasar pair (z = 0.586, O = 18.4, 19.2, and a separation of 2 ".3) associated with the radio source FIRST J164311.3+315618 (S(1400) = 120 mJy). The spectrum of the brighter quasar (A) has a much stronger narrow emission line spectrum than the other (B), and it also has stronger Balmer lines relative to the continuum. The continuum ratio of the spectra is flat in the blue (lambda(obs) < 6000 A) at about 2.1 but falls to 1.5 at longer wavelengths. A K' image shows two unresolved sources with a flux ratio of 1.3. The different colors appear to result from the contribution of the host galaxy of B, which is evident from Ca II and high-order Balmer absorption lines that are indicative of a substantial young stellar population. New 3.6 cm VLA observations show that the compact radio source is coincident with quasar A (B is only marginally detected). We rule out the lensing hypothesis because the optical flux ratio is A/B approximate to 1.5-2, while the radio flux ratio is A/B greater than or similar to 40, and conclude that this system is a binary. Moreover, the radio-loud quasar is a compact, steep spectrum source. FIRST J164311.3+315618A, B is the lowest redshift and smallest separation binary quasar yet identified. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Brotherton, MS (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, 7000 E Ave,POB 808,L-413, Livermore, CA 94551 USA. RI White, Richard/A-8143-2012 NR 28 TC 7 Z9 7 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1999 VL 514 IS 2 BP L61 EP L64 DI 10.1086/311956 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 195AD UT WOS:000080226200002 ER PT J AU Duff, MC Hunter, DB Bertsch, PM Amrhein, C AF Duff, MC Hunter, DB Bertsch, PM Amrhein, C TI Factors influencing uranium reduction and solubility in evaporation pond sediments SO BIOGEOCHEMISTRY LA English DT Article DE carbonate alkalinity; Chlorella; redox potential; sulfate reduction; uranium; XANES ID SAN-JOAQUIN VALLEY; REDOX; SOILS; SPECIATION; ADSORPTION; SELENIUM; ELEMENTS; USA; GEOCHEMISTRY; CALIFORNIA AB Evaporation ponds in the San Joaquin Valley (SJV), CA, USA that are used for the disposal of irrigation drainage waters, contain elevated levels of U that may be a threat to pond wildlife. The ponds support euryhaline algae, which become incorporated in the sediments as depositional organic matter (OM) - facilitating reducing conditions. Our earlier studies have shown that U in one SJV sediment was primarily present as the highly soluble U(VI) species (as opposed to the less soluble U(IV) species), despite the presence of volatile sulfides. in this research, we investigated the effects of native pond algae (Chlorella) and potential reducing agents on U redox chemistry of SJV pond sediments. San Joaquin Valley pond sediments were equilibrated with natural and synthetic pond inlet waters containing approximately 10 mg U(VI) L-1 to which reducing agents (acetate, sucrose, and alfalfa shoot) were added. The equilibrations were done under oxic (Chlorella only) and O-2-limiting: conditions (remaining treatments). Sediments were examined for changes in average U oxidation state by X-ray near-edge absorption structure (XANES) spectroscopy and U concentration by ICP-R-IS. For the alfalfa treatments, a 95 percent loss of U(VI) from solution, the presence of sulfides, and results from the XANES studies suggest U(VI) was reduced to U(IV). Upon exposure to air,the precipitated U was readily oxidized, suggesting the reduced U is susceptible to oxidation. Much less reduction of U(VI) was observed in the other 3 treatments and the solid phase was dominated by U(VI) as in the natural pond sediments. A second study was conducted with pond sediment-water suspensions to determine the effects of controlled PCO2 and low redox potential (Eh) on U solubility. These suspensions were equilibrated at 0.22 and 5.26 kPa PCO2 and allowed to "free-drift" from an oxidized to a reduced state. At high Eh and high PCO2, dissolved U concentrations were higher than in the low PCO2 systems due to greater complexation with CO3. Dissolved U concentrations decreased only under intense sulfate reducing conditions. even at low Eh conditions. It appears that U reduction occurred by chemical reduction via sulfide ion. Comparing the XANES data of the pond sediments with the laboratory-produced solids we conclude that biosorption by algae and bacteria is the dominant mechanism depositing Lr in the sediments. Even though there are organisms that can use U(VI) as a terminal electron acceptor, we found that sulfate reduction was preferred in these high-SO4 waters. Mixed oxidation state U-solids were preferentially formed in the pond sediments and in the lab except under intense SO4 reducing conditions. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Riverside, Dept Soil & Environm Sci, Riverside, CA 92521 USA. RP Duff, MC (reprint author), Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Drawer E, Aiken, SC 29802 USA. EM martine@srel.edu NR 46 TC 33 Z9 34 U1 0 U2 16 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-2563 J9 BIOGEOCHEMISTRY JI Biogeochemistry PD APR PY 1999 VL 45 IS 1 BP 95 EP 114 DI 10.1023/A:1006185812588 PG 20 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 172TC UT WOS:000078939900006 ER PT J AU Sobolev, V Sorokine, A Prilusky, J Abola, EE Edelman, M AF Sobolev, V Sorokine, A Prilusky, J Abola, EE Edelman, M TI Automated analysis of interatomic contacts in proteins SO BIOINFORMATICS LA English DT Article ID MACROMOLECULAR STRUCTURES; SECONDARY STRUCTURE; SIDE-CHAIN; DATA-BANK; DOCKING; PROGRAM; COMPLEMENTARITY; ACCESSIBILITY; SEQUENCE; SURFACE AB Motivation: New software has been designed to assist the molecular biologist in understanding the structural consequences of modifying a ligand and/or protein. Results: Tools are described for the analysis of ligand-protein contacts (LPC software) and contacts of structural units (CSU software) such as helices, sheets, strands and residues. Our approach is based on a detailed analysis of interatomic contacts and interface complementarity. For any ligand or structural unit, these software automatically: (i) calculate the solvent-accessible surface of every atom; (ii) determine the contacting residues and type of interaction they undergo (hydrophobic-hydrophobic, aromatic-aromatic, etc.); (iii) indicate all putative hydrogen bonds. LPC software further predicts changes in binding strength following chemical modification of the ligand. C1 Weizmann Inst Sci, Dept Plant Sci, IL-76100 Rehovot, Israel. Weizmann Inst Sci, Bioinformat Unit, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Sobolev, V (reprint author), Weizmann Inst Sci, Dept Plant Sci, IL-76100 Rehovot, Israel. RI Sorokin, Anatoly/A-9090-2008 OI Sorokin, Anatoly/0000-0002-0047-0606 NR 20 TC 557 Z9 569 U1 4 U2 17 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD APR PY 1999 VL 15 IS 4 BP 327 EP 332 DI 10.1093/bioinformatics/15.4.327 PG 6 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 197KF UT WOS:000080363400009 PM 10320401 ER PT J AU Thuman-Commike, PA Tsuruta, H Greene, B Prevelige, PE King, J Chiu, W AF Thuman-Commike, PA Tsuruta, H Greene, B Prevelige, PE King, J Chiu, W TI Solution X-ray scattering-based estimation of electron cryomicroscopy imaging parameters for reconstruction of virus particles SO BIOPHYSICAL JOURNAL LA English DT Article ID FROZEN-HYDRATED SPECIMENS; LASER RAMAN-SPECTROSCOPY; TOBACCO MOSAIC-VIRUS; CONTRAST TRANSFER; CRYOELECTRON MICROSCOPY; 3-DIMENSIONAL STRUCTURE; HALOBACTERIUM-HALOBIUM; COHERENT ILLUMINATION; PURPLE MEMBRANE; 400 KV AB Structure factor amplitudes and phases can be computed directly from electron cryomicroscopy images. Inherent aberrations of the electromagnetic lenses and other instrumental factors affect the structure factors, however, resulting in decreased accuracy in the determined three-dimensional reconstruction. In contrast, solution x-ray scattering provides absolute and accurate measurement of spherically averaged structure factor amplitudes of particles in solution but does not provide information on the phases. In the present study, we explore the merits of using solution x-ray scattering data to estimate the imaging parameters necessary to make corrections to the structure factor amplitudes derived from electron cryomicroscopic images of icosahedral virus particles. Using 400-kV spot scan images of the bacteriophage P22 procapsid, we have calculated an amplitude contrast of 8.0 +/- 5.2%, The amplitude decay parameter has been estimated to be 523 +/- 188 Angstrom(2) with image noise compensation and 44 +/- 66 Angstrom(2) without it. These results can also be used to estimate the minimum number of virus particles needed for reconstruction at different resolutions. C1 Baylor Coll Med, Verna & Marrs Mclean Dept Biochem, Houston, TX 77030 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. MIT, Dept Biol, Cambridge, MA 02142 USA. Univ Alabama, Dept Microbiol, Birmingham, AL 35294 USA. RP Chiu, W (reprint author), Baylor Coll Med, Verna & Marrs Mclean Dept Biochem, 1 Baylor Plaza, Houston, TX 77030 USA. EM wah@bcm.tmc.edu FU NCRR NIH HHS [P41RR02250]; NIGMS NIH HHS [GM17980, GM47980] NR 77 TC 28 Z9 29 U1 0 U2 3 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD APR PY 1999 VL 76 IS 4 BP 2249 EP 2261 PG 13 WC Biophysics SC Biophysics GA 184ZJ UT WOS:000079643400049 PM 10096920 ER PT J AU Zhu, YW Paszty, C Turetsky, T Tsai, S Kuypers, FA Lee, G Cooper, P Gallagher, PG Stevens, ME Rubin, E Mohandas, N Mentzer, WC AF Zhu, YW Paszty, C Turetsky, T Tsai, S Kuypers, FA Lee, G Cooper, P Gallagher, PG Stevens, ME Rubin, E Mohandas, N Mentzer, WC TI Stomatocytosis is absent in "stomatin"-deficient murine red blood cells SO BLOOD LA English DT Article ID INTEGRAL MEMBRANE-PROTEIN; INCREASED CATION PERMEABILITY; BAND 7.2B GENE; HEREDITARY STOMATOCYTOSIS; ERYTHROCYTE-MEMBRANES; NUCLEOTIDE-SEQUENCE; EXPRESSION; MICE; ORGANIZATION; TRANSPORT AB To examine the relationship between erythrocyte membrane protein 7.2b deficiency and the hemolytic anemia of human hereditary stomatocytosis, we created 7.2b knock-out mice by standard gene targeting approaches. Immunoblots showed that homozygous knock-out mice completely lacked erythrocyte protein 7.2b. Despite the absence of protein 7.2b, there was no hemolytic anemia and mouse red blood cells (RBCs) were normal in morphology, cell indices, hydration status, monovalent cation content, and ability to translocate lipids. The absence of the phenotype of hereditary stomatocytosis implies that protein 7.2b deficiency plays no direct role in the etiology of this disorder and casts doubt on the previously proposed role of this protein as a mediator of cation transport in RBC. (C) 1999 by The American Society of Hematology. C1 Univ Calif San Francisco, Dept Pediat, San Francisco, CA 94143 USA. Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06520 USA. Lawrence Berkeley Lab, Berkeley, CA USA. Childrens Hosp, Oakland Res Inst, Oakland, CA 94609 USA. RP Mentzer, WC (reprint author), San Francisco Gen Hosp, Room 331,Bldg 100,1001 Potrero Ave, San Francisco, CA 94110 USA. FU NHLBI NIH HHS [HL 31579]; NIDDK NIH HHS [DK 32094, DK 26263] NR 44 TC 49 Z9 50 U1 0 U2 3 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD APR 1 PY 1999 VL 93 IS 7 BP 2404 EP 2410 PG 7 WC Hematology SC Hematology GA 180GH UT WOS:000079377400033 PM 10090952 ER PT J AU Kennel, SJ Boll, R Stabin, M Schuller, HM Mirzadeh, S AF Kennel, SJ Boll, R Stabin, M Schuller, HM Mirzadeh, S TI Radioimmunotherapy of micrometastases in lung with vascular targeted Bi-213 SO BRITISH JOURNAL OF CANCER LA English DT Article DE vascular targeting; alpha-particle emitter; Bi-213; therapy ID MONOCLONAL-ANTIBODY; SOLID TUMORS; ENDOTHELIAL-CELLS; MICE BEARING; THERAPY; ANGIOGENESIS; GROWTH; INHIBITION; INVIVO; INTERLEUKIN-2 AB A model system has been used to test the efficacy of vascular targeting of alpha-particle emitter Bi-213 for therapy of small, 'artificial' metastases in mouse lung. Specific monoclonal antibody (mAb) 201B was used to deliver greater than 30% of the injected dose to lung where tumours had developed due to intravenous injection of cells. Specific Bi-213-mAb 201B treatment of BALB/c mammary carcinoma EMT-6 tumours in lung resulted in a dose-dependent destruction of tumours and an extended lifespan of treated animals relative to controls, Significant reduction of lung tumour burden was noted in animals treated with 0.93 MBq injected dose or as little as 14 Gy absorbed dose to the lung. Animals treated with higher doses (2.6-6.7 MBq) had nearly complete cure of lung tumours but eventually died of lung fibrosis induced by the treatment. Four other tumour cell types were studied: murine Line 1 lung carcinomas in syngeneic BALB/c mice, rat IC-12 tracheal carcinoma growing in severe combined immune deficient (SCID) mice, and two human tumours - epidermoid carcinoma A431 and lung carcinoma A549 - growing in SCID mice. In all cases, the number of lung tumour colonies was reduced in animals treated with specific, labelled mAb relative to those in animals treated with control Bi-213 MAb or EDTA complexed Bi-213. Tumours treated in immunodeficient SCID mice were partially destroyed or at least retarded in growth, but ultimately regrew and proved fatal, indicating that an intact immune function is necessary for complete cure. The data show that the short-lived alpha-particle emitter Bi-213 can be effectively targeted to lung blood vessels and that tumour cells growing in the lung are killed. The mechanism may involve direct killing of tumour cells from alpha-particle irradiation, killing through destruction of blood supply to the tumour, or a combination of the two. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Div Med Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Coll Vet Med, Expt Oncol Lab, Knoxville, TN 37901 USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 2008,MS-6101, Oak Ridge, TN 37831 USA. RI Boll, Rose/C-4138-2016 OI Boll, Rose/0000-0003-2507-4834 NR 34 TC 57 Z9 59 U1 1 U2 5 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 APR PY 1999 VL 80 IS 1-2 BP 175 EP 184 DI 10.1038/sj.bjc.6990337 PG 10 WC Oncology SC Oncology GA 191NP UT WOS:000080028700026 PM 10389994 ER PT J AU Phillips, WS AF Phillips, WS TI Empirical path corrections for regional-phase amplitudes SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SEISMIC DISCRIMINANTS; WESTERN CHINA; WAVE-PROPAGATION; CENTRAL-ASIA; IDENTIFICATION; EURASIA; LG AB Using data from 385 events recorded at Lanzhou in central China, I compare two empirical methods for predicting and correcting for path effects on regional-phase amplitude ratios. The first method interpolates source- and distance corrected seismic data to create geographical, path-correction surfaces. The second, or wave-guide, method employs correlations with path-averaged physical data such as topography to correct the seismic data. Path corrections can vary over an order of magnitude, and their use will sharpen differences in regional-phase ratios arising from different types of natural and man-made sources of seismic energy and, thus, will be important for monitoring a Comprehensive Test Ban Treaty. For P-g/L-g phase ratios in the band 0.5 to 1 Hz, interpolated path corrections reduced variance best using kriging (62%) and nearly as well using a radius 250 km, moving-window-mean smoother (56%). Wave-guide methods based on mean and rms topography reduced variance by 43%. Variance reduction is given relative to the standard correction for distance alone. Wave-guide methods were further tested by attempting to find correlations with topographic data that had been rotated geographically. For conservatively chosen sets of wave-guide parameters, the true orientations yielded the best variance reduction, adding confidence to the use of this method. Wave-guide methods complement interpolation methods because they extrapolate behavior beyond active seismic areas. However, I find broad regions that are fit poorly by wave-guide predictions, especially where the path effect changes rapidly, such as along the eastern edge of the Tibetan plateau where P-g/L-g ratios are underpredicted. The two methods can be combined using Bayesian kriging, forcing predictions to fit the data in seismically active areas and allowing more powerful extrapolation beyond. C1 Univ Calif Los Alamos Natl Lab, Los Alamos Seism Res Ctr, Los Alamos, NM 87545 USA. RP Phillips, WS (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Seism Res Ctr, MS C335, Los Alamos, NM 87545 USA. NR 21 TC 26 Z9 26 U1 0 U2 1 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD APR PY 1999 VL 89 IS 2 BP 384 EP 393 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 185ZR UT WOS:000079702000006 ER PT J AU Rodgers, AJ Walter, WR Schultz, CA Myers, SC Lay, T AF Rodgers, AJ Walter, WR Schultz, CA Myers, SC Lay, T TI A comparison of methodologies for representing path effects on regional P/S discriminants SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID WESTERN UNITED-STATES; SEISMIC DISCRIMINANTS; WAVE-PROPAGATION; NTS EXPLOSIONS; CHINA; EARTHQUAKES; EURASIA; PHASE; LG; IDENTIFICATION AB Short-period regional P/S amplitude ratios hold much promise for discriminating low-magnitude explosions from earthquakes in a Comprehensive Test Ban Treaty (CTBT) monitoring context. However, propagation path effects lead to variability in regional-phase amplitudes that, if not accounted for, can reduce or eliminate the ability of P/S ratios to identify the seismic source. Here we compare four different methodologies that account for the effect of heterogeneous structure on P/S amplitude variance: (1) distance corrections, (2) path-specific crustal waveguide parameter regressions, (3) cap averaging (running mean smoothing), and (4) kriging, The predictability of each method is established by cross-validation (leave-one-out) analysis. We apply these techniques to Pn/Lg, Pg/Lg, and Pn/Sn observations in three frequency bands from 0.75 to 6.0 Hz at station ABKT (Alibek, Turkmenistan), site of a primary station of the International Monitoring System (IMS), Paths to ABKT sample diverse crustal structures (e.g, various topographic, sedimentary, and geologic structures), leading to great variability in the observed P/S amplitude ratios. For these data to be useful for isolating source characteristics, the scatter needs to be reduced by accounting for the path effects, and the resulting distribution needs to be Gaussian for most existing spatial interpolation and discrimination strategies to have valid application. Each method reduces the scatter of the P/S amplitude measurements with varying degrees of success; however, kriging has the distinct advantages of providing the greatest variance reduction and a continuous correction surface with an estimate of the model uncertainty. The largest reductions in scatter are found for the lowest frequency P/S ratios (<3.0 Hz). C1 Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, Livermore, CA 94551 USA. Univ Calif Santa Cruz, Inst Tecton, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. RP Rodgers, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, Livermore, CA 94551 USA. RI Rodgers, Arthur/E-2443-2011; Walter, William/C-2351-2013; Myers, Stephen/K-1368-2014 OI Walter, William/0000-0002-0331-0616; Myers, Stephen/0000-0002-0315-5599 NR 37 TC 20 Z9 23 U1 0 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD APR PY 1999 VL 89 IS 2 BP 394 EP 408 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 185ZR UT WOS:000079702000007 ER PT J AU Stump, BW Pearson, DC Reinke, RE AF Stump, BW Pearson, DC Reinke, RE TI Source comparisons between nuclear and chemical explosions detonated at Rainier Mesa, Nevada Test Site SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID UNITED-STATES EARTHQUAKES; NTS EXPLOSIONS; DISCRIMINATION AB A series of nuclear [MINERAL QUARRY (MQ), HUNTERS TROPHY (HT)I and chemical [NON-PROLIFERATION EXPERIMENT (NPE) and NPE CAL] explosions were detonated in the same geological material at Rainier Mesa, Nevada Test Site. These sources were extensively instrumented with the same near-source, free-surface instrumentation array. The data from these explosions allow the establishment of empirical source scaling relations as well as investigation of possible chemical and nuclear source differences. Even in the near-source region at common receivers, the data display propagation path effects resulting from slight differences in source locations. These effects are effectively taken into account by smoothing the source comparisons across the different stations in the receiver array. As many as 30 individual waveforms from each source are used in this smoothing process. Comparison of HT and NPE at near-source distances indicates that within the bandwidth of the data (0.36 to 100 Hz), there is no apparent spectral difference between the nuclear and single-fired chemical source. The smoothed spectral ratio between the NPE and NPE CAL is consistent with the long-period source spectral difference (10(4)), corner frequencies (2 to 3 Hz/NPE and 40 to 60 Hz/NPE GAL), and high-frequency decay f(-2)) similar to the Mueller-Murphy source model for wet tuff after modifying the cavity radius to scale as the cube root of yield. Comparison of the two nuclear sources, HT and MQ, indicates that at long periods, the HT/MQ ratio is 0.4 to 0.6 with the spectra from the two explosions merging above 5 Hz, which is consistent with the 0.3 magnitude difference observed for the two sources. In all the source comparisons, the spectral ratios of the transverse components of motion are indistinguishable from those produced by either the vertical or radial components. This fact argues that the transverse component of motion from an explosion is generated at very close-in distances, in this case on the order of 1 to 2 km. These observations are in agreement with some type of linear scattering mechanism. C1 So Methodist Univ, Dept Geol Sci, Dallas, TX 75275 USA. Los Alamos Natl Lab, Geophys Grp, Los Alamos, NM 87545 USA. Def Threat Reduct Agcy, Kirtland AFB, NM 87117 USA. RP So Methodist Univ, Dept Geol Sci, POB 750395, Dallas, TX 75275 USA. NR 34 TC 22 Z9 23 U1 1 U2 3 PU SEISMOLOGICAL SOC AMER PI ALBANY PA 400 EVELYN AVE, SUITE 201, ALBANY, CA 94706-1375 USA SN 0037-1106 EI 1943-3573 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD APR PY 1999 VL 89 IS 2 BP 409 EP 422 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 185ZR UT WOS:000079702000008 ER PT J AU Myers, SC Walter, WR Mayeda, K Glenn, L AF Myers, SC Walter, WR Mayeda, K Glenn, L TI Observations in support of Rg scattering as a source for explosion S waves: Regional and local recordings of the 1997 Kazakhstan depth of burial experiment SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID UNDERGROUND NUCLEAR-EXPLOSIONS; NTS EXPLOSIONS; EARTHQUAKES; DISCRIMINATION; RATIOS; SPALL; LG AB In August and September of 1997, three 25-ton chemical explosions were detonated at nominal depths of 550, 300, and 50 m in boreholes at the former Soviet test site at Balapan, Kazakhstan. One objective of this experiment was to evaluate the effect of differing source depth on the regional wave field. Analysis of regional seismic phases lead to the observation that regional P/S wave amplitude ratios in the 1- to 5-Hz band increase as a function of source depth. However, at frequencies greater than about 5 Hz, the relative amplitudes of P and S waves remain approximately constant for the differing depth shots. Similarly, regional coda spectra an amplified in the 1- to 5-Hz band for the shallow shots. At local distances, Rg is the dominant seismic phase, with peak amplitudes in the 0.7- to 5-Hz range, and Re is strongest for the shallower shots. Within the short distance spanned by the local stations (<20 km), Rg is rapidly attenuated, and the attenuation is accompanied by a significant shift in peak amplitude toward lower frequency. At regional distances, Rg is below the noise level. The coincident frequency band in which local Rg rapidly loses energy and regional S phases are amplified points toward Re scattering as the dominant mechanism causing the discrepancies between P/S amplitude ratios in this study. These observations are particularly relevant to the understanding of physical processes affecting regional P/S discriminants and may lead to improvements in discriminant methods. C1 Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, Livermore, CA 94551 USA. RP Myers, SC (reprint author), Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, POB 808,L-202, Livermore, CA 94551 USA. RI Walter, William/C-2351-2013; Myers, Stephen/K-1368-2014 OI Walter, William/0000-0002-0331-0616; Myers, Stephen/0000-0002-0315-5599 NR 16 TC 32 Z9 33 U1 0 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD APR PY 1999 VL 89 IS 2 BP 544 EP 549 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 185ZR UT WOS:000079702000018 ER PT J AU Pearson, WH Elston, RA Bienert, RW Drum, AS Antrim, LD AF Pearson, WH Elston, RA Bienert, RW Drum, AS Antrim, LD TI Why did the Prince William Sound, Alaska, Pacific herring (Clupea pallasi)fisheries collapse in 1993 and 1994? Review of hypotheses SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Editorial Material ID VALDEZ OIL-SPILL; CLUPEA-HARENGUS-PALLASI; HEMORRHAGIC SEPTICEMIA VIRUS; BRITISH-COLUMBIA; FISH STOCKS; NORTH-SEA; PETROLEUM-HYDROCARBONS; POPULATION-DYNAMICS; TOXIC-CHEMICALS; CRUDE-OIL AB Following record harvests of Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, in the 3 years after the Exxon Valdez oil spill, the fishery failed in 1993. The hypotheses advanced to explain this dramatic 1993 decline occur in three categories: (i) effects associated with the 1989 oil spill, (ii) harvesting effects, and (iii) natural phenomena. Based on our review, we are convinced that a combination of increasing Prince William Sound herring biomass and decreasing food supply led to poor condition of Prince William Sound herring, which resulted in the 1993 decline. Other natural causes could have contributed to the decline, including disease, cold water temperatures, increased predation, and other natural stochastic processes. No evidence supports hypotheses that the decline resulted solely from overharvesting or underharvesting. The record high population levels and harvests of Prince William Sound herring in the years after the 1989 oil spill, the lack of change from the expected age-class distribution, and the low level of oil exposure documented for herring in 1989 and the following years all indicate that the 1989 oil spill did not contribute to the 1993 decline. Poor nutritional status, either alone or in combination with disease or other natural factors, was most likely responsible for the 1993 collapse. C1 Battelle Marine Sci Lab, Sequim, WA 98382 USA. AquaTechn Inc, Carlsborg, WA 98324 USA. Int Environm Serv, Seattle, WA 98125 USA. RP Antrim, LD (reprint author), Battelle Marine Sci Lab, 1529 W Sequim Bay Rd, Sequim, WA 98382 USA. NR 134 TC 29 Z9 32 U1 2 U2 16 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1999 VL 56 IS 4 BP 711 EP 737 DI 10.1139/cjfas-56-4-711 PG 27 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 209BR UT WOS:000081027900017 ER PT J AU Barr, FG Bissell, M Vande Woude, G Israel, M Sharp, P AF Barr, FG Bissell, M Vande Woude, G Israel, M Sharp, P TI The role of chimeric paired box transcription factors in the pathogenesis of pediatric rhabdomyosarcoma - Discussion SO CANCER RESEARCH LA English DT Editorial Material C1 Univ Penn, Sch Med, Dept Pathol & Lab Med, Philadelphia, PA 19104 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Dept Neurosurg, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Pediat, San Francisco, CA 94143 USA. Univ Calif San Francisco, Preuss Lab Mol Neurooncol, San Francisco, CA 94143 USA. MIT, Ctr Canc Res, Dept Biol, Cambridge, MA 02139 USA. RP Barr, FG (reprint author), Univ Penn, Sch Med, Dept Pathol & Lab Med, Philadelphia, PA 19104 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD APR 1 PY 1999 VL 59 IS 7 SU S BP 1715S EP 1715S PG 1 WC Oncology SC Oncology GA 183YH UT WOS:000079582000012 ER PT J AU Bissell, MJ Weaver, VM Lelievre, SA Wang, F Petersen, OW Schmeichel, KL AF Bissell, MJ Weaver, VM Lelievre, SA Wang, F Petersen, OW Schmeichel, KL TI Tissue structure, nuclear organization, and gene expression in normal and malignant breast SO CANCER RESEARCH LA English DT Article; Proceedings Paper CT General-Motors-Cancer-Research-Foundation 20th Annual Scientific Conference - Developmental Biology and Cancer CY JUN 09-10, 1998 CL BETHESDA, MARYLAND SP Gen Motors Canc Res Fdn ID MAMMARY EPITHELIAL-CELLS; EXTRACELLULAR-MATRIX; SIGNAL-TRANSDUCTION; TRANSCRIPTIONAL ENHANCER; RECIPROCAL INTERACTIONS; DEPENDENT REGULATION; DIFFERENTIATION; APOPTOSIS; INTEGRINS; ADHESION AB Because every cell within the body has the same genetic information, a significant problem in biology is to understand how cells within a tissue express genes selectively. A sophisticated network of physical and biochemical signals converge in a highly orchestrated manner to bring about the exquisite regulation that governs gene expression in diverse tissues. Thus, the ultimate decision of a cell to proliferate, express tissue-specific genes, or apoptose must be a coordinated response to its adhesive, growth factor, and hormonal milieu. The unifying hypothesis examined in this overview is that the unit of function in higher organisms is neither the genome nor the cell alone but the complex, three-dimensional tissue. This is because there are bidirectional connections between the components of the cellular microenvironment (growth factors, hormones, and extracellular matrix) and the nucleus. These connections are made via membrane-bound receptors and transmitted to the nucleus, where the signals result in modifications to the nuclear matrix and chromatin structure and lead to selective gene expression. Thus, cells need to be studied "in context", i.e., within a proper tissue structure, if one is to understand the bidirectional pathways that connect the cellular microenvironment and the genome, In the last decades, we have used well-characterized human and mouse mammary cell lines in "designer microenvironments" to create an appropriate context to study tissue-specific gene expression, The use of a three-dimensional culture assay, developed with reconstituted basement membrane, has allowed us to distinguish normal and malignant human breast cells easily and rapidly. Whereas normal cells become growth arrested and form organized "acini," tumor cells continue to grow, pile up, and in general fail to respond to extracellular matrix and microenvironmental cues. By correcting the extracellular matrix-receptor (integrin) signaling and balance, we have been able to revert the malignant phenotype when a human breast tumor cell is cultured in, or on, a basement membrane. Most recently, we have shown that whereas beta 1 integrin and epidermal growth factor receptor signal transduction pathways are integrated reciprocally in three-dimensional cultures, on tissue culture plastic (two-dimensional monolayers), these are not coordinated. Finally, we have demonstrated that, rather than passively reflecting changes in gene expression, nuclear organization itself can modulate cellular and tissue phenotype, We conclude that the structure of the tissue is dominant over the genome, and that we may need a new paradigm for how epithelial-specific genes are regulated in vivo. We also argue that unless the structure of the tissue is critically altered, malignancy will not progress, even in the presence of multiple chromosomal mutations. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Copenhagen, Panum Inst, DK-2200 Copenhagen N, Denmark. RP Bissell, MJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 61 TC 82 Z9 82 U1 0 U2 1 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD APR 1 PY 1999 VL 59 IS 7 SU S BP 1757S EP 1763S PG 7 WC Oncology SC Oncology GA 183YH UT WOS:000079582000026 ER PT J AU DiGiovanni, J Johnston, DA Rupp, T Sasser, LB Anderson, LE Morris, JE Miller, DL Kavet, R Walborg, EF AF DiGiovanni, J Johnston, DA Rupp, T Sasser, LB Anderson, LE Morris, JE Miller, DL Kavet, R Walborg, EF TI Lack of effect of a 60 Hz magnetic field on biomarkers of tumor promotion in the skin of SENCAR mice SO CARCINOGENESIS LA English DT Article ID POLYAMINE-BIOSYNTHETIC ENZYMES; MOUSE-SKIN; DNA-SYNTHESIS; INDUCTION; CHRYSAROBIN; EPIDERMIS; EXPOSURE; AGENTS AB It has been proposed that extremely low frequency magnetic fields may enhance tumorigenesis through a co-promotional mechanism. This hypothesis has been further tested using the two-stage model of mouse skin carcinogenesis, i.e. 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced promotion of skin carcinogenesis in mice initiated by a single subcarcinogenic dose of 7,12-dimethylbenz[a]anthracene. Experimentation utilized three different doses of TPA within its dose-response range (0.85, 1.70 or 3.40 nmol) and examined the following early biomarkers of tumor promotion after 1, 2 and 5 weeks of promotion: increases in epidermal thickness and the labeling index of epidermal cells, induction of epidermal ornithine decarboxylase activity and down-regulation of epidermal protein kinase C activity, Mice exposed to a 60 Hz magnetic field having a flux density of 2 mT for 6 h/day for 5 days/week were compared with mice exposed to an ambient magnetic field. Within the sensitivity limits of the biomarker methodology and the exposure parameters employed, no consistent, statistically significant effects indicative of promotion or co-promotion by the magnetic field were demonstrated. C1 Univ Texas, MD Anderson Cancer Ctr, Sci Pk Res Div, Smithville, TX 78957 USA. Pacific NW Lab, Richland, WA 99352 USA. Elect Power Res Inst, Palo Alto, CA 94304 USA. Dermigen Inc, Smithville, TX 78957 USA. RP DiGiovanni, J (reprint author), Univ Texas, MD Anderson Cancer Ctr, Sci Pk Res Div, POB 389, Smithville, TX 78957 USA. FU NIEHS NIH HHS [ES07784] NR 19 TC 4 Z9 4 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD APR PY 1999 VL 20 IS 4 BP 685 EP 689 DI 10.1093/carcin/20.4.685 PG 5 WC Oncology SC Oncology GA 186EL UT WOS:000079714300024 PM 10223200 ER PT J AU Malfatti, MA Kulp, KS Knize, MG Davis, C Massengill, JP Williams, S Nowell, S MacLeod, S Dingley, KH Turteltaub, KW Lang, NP Felton, JS AF Malfatti, MA Kulp, KS Knize, MG Davis, C Massengill, JP Williams, S Nowell, S MacLeod, S Dingley, KH Turteltaub, KW Lang, NP Felton, JS TI The identification of [2-C-14]2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine metabolites in humans SO CARCINOGENESIS LA English DT Article ID CARCINOGEN 2-AMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE PHIP; FOOD MUTAGEN 2-AMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE; HYDROXY HETEROCYCLIC AMINES; LIVER-MICROSOMES; COOKED-FOOD; RAT-LIVER; HEPATIC MICROSOMES; ACTIVATION; DNA; 2-HYDROXYAMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE AB [2-C-14]2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine ([C-14]PhIP), a putative human carcinogenic heterocyclic amine found in well-done cooked meat, was administered orally to three colon cancer patients undergoing a partial colonectomy, Forty-eight to seventy-two hours prior to surgery, subjects received a 70-84 mu g dose of C-14. Urine and blood were analyzed by HPLC for PhIP and PhIP metabolites. Metabolites were identified based on HPLC co-elution with authentic PhIP metabolite standards, mass spectral analysis and susceptibility to enzymatic cleavage. In two subjects, similar to 90% of the administered [C-14]PhIP dose was eliminated in the urine, whereas in the other, only 50% of the dose was found in the urine. One subject excreted three times more radioactivity in the first 4 h than did the others. Twelve radioactive peaks associated with PhIP were detected in the urine samples. The relative amount of each metabolite varied by subject, and the amounts of each metabolite within subjects changed over time. In all three subjects the most abundant urinary metabolite was identified as 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine-N-2-glucuronide (N-hydroxy-PhIP-N-2-glucuronide), accounting for 47-60% of the recovered counts in 24 h, PhIP accounted for <1% of the excreted radiolabel in all three patients. Other metabolites detected in the urine at significant amounts were 4-(2-amino-1-methylimidazo[4,5-b]pyrid-6-yl)phenyl sulfate, N-hydroxy-PhIP-N-3-glucuronide and PhIP-N-2-glucuronide. In the plasma, N-hydroxy-PhIP-N-2-glucuronide accounted for 60, 18 and 20% of the recovered plasma radioactivity at 1 h post PhIP dose in subjects 1, 2 and 3 respectively. Plasma PhIP was 56-17% of the recovered dose at 1 h post exposure. The relatively high concentration of N-hydroxy-PhIP-N-2-glucuronide and the fact that it is an indicator of bioactivation make this metabolite a potential biomarker for PhIP exposure and activation. Determining the relative differences in PhIP metabolites among individuals will indicate metabolic differences that may predict individual susceptibility to carcinogenic risk from this suspected dietary carcinogen. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Univ Arkansas Med Sci, Arkansas Canc Res Ctr, Little Rock, AR 72205 USA. John L McClellan Mem Vet Adm Med Ctr, Little Rock, AR 72205 USA. RP Felton, JS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. FU NCI NIH HHS [CA55751, CA55861, CA58697] NR 43 TC 85 Z9 86 U1 0 U2 6 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD APR PY 1999 VL 20 IS 4 BP 705 EP 713 DI 10.1093/carcin/20.4.705 PG 9 WC Oncology SC Oncology GA 186EL UT WOS:000079714300027 PM 10223203 ER PT J AU Kent, AJR Norman, MD Hutcheon, ID Stolper, EM AF Kent, AJR Norman, MD Hutcheon, ID Stolper, EM TI Assimilation of seawater-derived components in an oceanic volcano: evidence from matrix glasses and glass inclusions from Loihi seamount, Hawaii SO CHEMICAL GEOLOGY LA English DT Article DE Hawaii; Loihi seamount; glass inclusions; assimilation; seawater ID SCIENTIFIC DRILLING PROJECT; DIVERSE BASALT TYPES; MID-ATLANTIC RIDGE; EAST PACIFIC RISE; ISOTOPIC COMPOSITION; PHASE-SEPARATION; TRACE-ELEMENTS; NOBLE-GASES; CHLORINE; LAVAS AB We report major element, H2O, Cl, B, and Be analyses of matrix glass and olivine-hosted glass inclusions from two pillow lava samples dredged from 4200 m on the southern rift zone of Loihi seamount, Hawaii. Matrix glasses (MgO similar to 9 wt.%) have H2O, Cl, and B contents considerably in excess of the values expected from mantle melting or fractional crystallization of parental Loihi magmas. Glass inclusions have H2O, Cl, and B contents ranging from the high values of the matrix glasses to lower concentrations that are more typical of Hawaiian magmas. Concentrations of other incompatible elements (e.g., K2O, P2O5, and Be) in matrix glasses and glass inclusions are uncorrelated with their H2O, Cl, and B contents. Glass inclusions show considerable scatter in major element compositions compared to matrix glasses, but except for H2O, Cl, and B, the average glass inclusion composition corresponds well to the matrix glass compositions. We propose that the glass inclusions represent compositionally diverse liquids present within the magmatic plumbing system at Loihi that were mixed and homogenized to produce the liquid that quenched to the matrix glass on eruption. This range of liquid compositions present at depth was trapped by crystallizing olivine prior to blending and homogenizing and therefore preserves a compositional diversity not present in erupted whole rocks. The high H2O, Cl, and B contents of matrix glasses and some glass inclusions, and the range of H2O, Cl, and B concentrations in glass inclusions, are best explained by variable extents of assimilation by Loihi magmas of H2O-Cl-B-rich, seawater-derived components prior to eruption. The required assimilants range from material similar in composition to seawater to materials with Cl/H2O and B/H2O ratios much higher than seawater. Our preferred explanation (similar to that suggested for MORE by Michael and Schilling, 1989) [Michael, P.J., Schilling, J.-G., 1989. Chlorine in mid-ocean ridge magmas: Evidence for assimilation of seawater-influenced components. Geochim. Cosmochim. Acta, 53, pp. 3131-3143.] is that most of the assimilated materials were brines (or rocks containing brines in inclusions or along grain boundaries) enriched in Cl by high temperature phase separation of seawater in sub-sea-floor hydrothermal circulation systems. Addition of similar to 1.0 wt.% of a 15 wt.% NaCl brine can explain the H2O and Cl contents of the matrix glasses. Addition of altered basalt cannot readily account for the Cl and H2O contents. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Macquarie Univ, Sch Earth Sci, GEMOC, N Ryde, NSW 2109, Australia. RP Kent, AJR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. EM kent5@llnl.gov NR 58 TC 79 Z9 81 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD APR PY 1999 VL 156 IS 1-4 BP 299 EP 319 DI 10.1016/S0009-2541(98)00188-0 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 181JQ UT WOS:000079438600016 ER PT J AU Ma, M Li, DQ AF Ma, M Li, DQ TI New organic nanoporous polymers and their inclusion complexes SO CHEMISTRY OF MATERIALS LA English DT Article ID INDUCED CIRCULAR-DICHROISM; BETA-CYCLODEXTRIN; DERIVATIVES; SORPTION; BENZENES; SPECTRA AB By cross-linking cyclodextrin molecules with bifunctional linkers, we have synthesized a new class of nanoporous polymers with a narrow pore size distribution(ca. 1 nm). These polymers behave like nanosponges that spontaneously absorb common organic molecules from aqueous solutions. The significance is that such materials may be useful for ultrapure water applications which are critical for semiconductor manufacturing. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST4, Los Alamos, NM 87545 USA. RP Li, DQ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST4, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 71 Z9 73 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD APR PY 1999 VL 11 IS 4 BP 872 EP + DI 10.1021/cm981090y PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 188KN UT WOS:000079845700008 ER PT J AU Lee, YJ Kim, SJ Wu, G Parise, JB AF Lee, YJ Kim, SJ Wu, G Parise, JB TI Structural characterization of the gallosilicate TsG-1, K10Ga10Si22O64 center dot 5H(2)O, with the CGS framework topology SO CHEMISTRY OF MATERIALS LA English DT Article ID POWDER DIFFRACTION; ZEOLITE; CATALYSTS AB The synthetic gallosilicate TsG-1 with the CGS framework topology has been synthesized under hydrothermal conditions and characterized via single-crystal synchrotron X-ray diffraction. Unlike the cobalt-gallium phosphate analogue, this material shows the ideal topological symmetry of Pnma (a = 8.613(2) Angstrom, b = 13.813(3) Angstrom, c = 16.330(3) Angstrom), and extraframework cations are distributed over the buckled 8-ring sites of the interpenetrated double 6-rings as well as along the channels of the s-shaped 10-rings and elliptical 8-rings. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source 725, SUNY X3 Beamline, Upton, NY 11973 USA. RP Parise, JB (reprint author), SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RI Lee, Yongjae/K-6566-2016 NR 18 TC 12 Z9 12 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD APR PY 1999 VL 11 IS 4 BP 879 EP + DI 10.1021/cm981156p PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 188KN UT WOS:000079845700010 ER PT J AU MacLachlan, A AF MacLachlan, A TI The future of the national laboratories SO CHEMTECH LA English DT Article C1 US Dept Energy, Undersecretary R&D Management, Washington, DC 20585 USA. RP MacLachlan, A (reprint author), 301 Centennial Circle, Wilmington, DE 19807 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2703 J9 CHEMTECH JI Chemtech PD APR PY 1999 VL 29 IS 4 BP 47 EP 50 PG 4 WC Chemistry, Applied SC Chemistry GA 184KM UT WOS:000079611400010 ER PT J AU Sposito, G Park, SH Sutton, R AF Sposito, G Park, SH Sutton, R TI Monte Carlo simulation of the total radial distribution function for interlayer water in sodium and potassium montmorillonites SO CLAYS AND CLAY MINERALS LA English DT Article DE adsorbed water; montmorillonite; neutron diffraction; water ID MOLECULAR-DYNAMICS SIMULATIONS; SWELLING CLAY-MINERALS; DOUBLE-LAYER STRUCTURE; NEUTRON-DIFFRACTION; AQUEOUS-SOLUTIONS; VERMICULITE; HYDRATION; ADSORPTION; DESORPTION; HYSTERESIS AB Monte Carlo simulations based on tested water-water, cation-water, and water-clay potential functions were applied to calculate radial distribution functions for O-O, O-H and H-H spatial correlations in the interlayer region of the two-layer hydrates of Na- and K-montmorillonite. The simulated radial distribution functions: then were used to compute the total radial distribution function for interlayer water, a physical quantity that can be determined experimentally by H/D isotopic-difference neutron diffraction. The simulated total radial distribution functions were compared with that for bulk liquid water, and with a total radial distribution function determined experimentally for the two-layer hydrate of Na-montmorillonite by Powell ct al. (1997). This comparison suggested that water molecules in the two-layer hydrate of montmorillonite have nearest-neighbor configurations which differ significantly from the tetrahedral ordering of nearest neighbors that characterizes bulk liquid water. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Sposito, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Mail Stop 90-1116, Berkeley, CA 94720 USA. NR 32 TC 45 Z9 45 U1 0 U2 8 PU CLAY MINERALS SOCIETY PI BOULDER PA PO BOX 4416, BOULDER, CO 80306 USA SN 0009-8604 J9 CLAY CLAY MINER JI Clay Clay Min. PD APR PY 1999 VL 47 IS 2 BP 192 EP 200 DI 10.1346/CCMN.1999.0470209 PG 9 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 191DU UT WOS:000080007100009 ER PT J AU Pawson, S Fiorino, M AF Pawson, S Fiorino, M TI A comparison of reanalyses in the tropical stratosphere. Part 3: Inclusion of the pre-satellite data era SO CLIMATE DYNAMICS LA English DT Article ID QUASI-BIENNIAL OSCILLATION; TEMPERATURE AB In this study, previous evaluations of the monthly mean structure of the tropical lower stratosphere in reanalyzed datasets are extended to include the period 1958-1978, when no satellite-based observations were available. It is shown that a large discontinuity, in temperatures near the tropical tropopause, in the NCEP data occurred when the Tires Operational Vertical Sounder (TOVS) became operational. When only rawinsonde data were available, the tropopause temperatures in the NCEP dataset are in better agreement with ERA data for TOVS period. Both NCEP and NASA reanalyses show similar deviations from the ERA data in the TOVS renalyses show similar deviations from the ERA data in the TOVS period. There is also a stepwise change in the lower stratospheric meridional velocity when the TOVS data were introduced into the NCEP reanalyses. This discontinuity is such that in the 1958-1978 period, the annual cycle in zonal mean meridional velocity in the NCEP data resembles that of the ERA data in the 1979-1993 period. The differences are shown to result from large changes in the local meridional flow in the Indonesian region. The temporal consistency of the QBO is examined; it is shown that the NCEP assimilation system is sensitive to the data available. There is a change in the zonally asymmetric structure of the zonal wind over time, presumably related to the changes in input data and the inability of the model to represent the three-dimensional structure of the tropical lower stratosphere. These results provide further evidence of the value of rawinsonde data in data assimilation systems as well as the need to use satellite radiance data in an appropriate manner. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. RP Pawson, S (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RI Fiorino, Michael/N-4150-2014; Pawson, Steven/I-1865-2014 OI Fiorino, Michael/0000-0002-2819-8157; Pawson, Steven/0000-0003-0200-717X NR 16 TC 41 Z9 43 U1 1 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD APR PY 1999 VL 15 IS 4 BP 241 EP 250 DI 10.1007/s003820050279 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 188UQ UT WOS:000079867400001 ER PT J AU Barlow, RS Smith, NSA Chen, JY Bilger, RW AF Barlow, RS Smith, NSA Chen, JY Bilger, RW TI Nitric oxide formation in dilute hydrogen jet flames: Isolation of the effects of radiation and turbulence-chemistry submodels SO COMBUSTION AND FLAME LA English DT Article ID DIFFUSION FLAMES; NITROGEN EMISSIONS; DAMKOHLER NUMBER; FLOW; COMBUSTION; NO AB Nitric oxide (NO) levels in turbulent flames are sensitive to temperature, O atom concentrations, and residence times at the NO forming conditions. Consequently, accurate prediction of NO formation is a challenge for turbulent combustion models. and NO is a useful scalar to consider when evaluating turbulence-chemistry submodels. Predictions of NO formation in a series of hydrogen flames with varying levels of helium dilution are compared with experimental results. Dilution reduces flame radiation to the point where uncertainties in the radiation calculation have only a small influence on NO emission. and this allows different models for the coupling of turbulence and chemistry to be compared in relative isolation from the effects of radiation. Calculations using the Probability Density Function (PDF) method and the Conditional Moment Closure (CMC) method are carried out using the same turbulence model, radiation model, reduced chemical mechanism, and boundary conditions, so that similarities and differences between these two approaches for the coupling of turbulence and chemistry may be isolated and more fully understood. To accomplish this, flow model constants are adjusted to match measured axial profiles of mean velocity and mixture fraction in the undiluted flame, before detailed scalar comparisons are carried out. The optically thin radiation assumption is shown to be appropriate for these hydrogen flames, and the effects of flame radiation on NO emission are examined. The sensitivities of the calculated results to certain boundary conditions and submodels are also quantified. Both turbulence-chemistry models yield good results for conditional mean temperature and H2O mole fraction. Results also show that both models yield quantitatively useful predictions for the NO formation and emission. With all other submodels being the same, the PDF method predicts lower NO levels than does the CMC method. This difference is associated with lower O atom concentrations predicted by the PDF method. Both methods underpredict NO formation in the lower portion of the jet flames. This deficiency is attributed to the effects of differential diffusion, which are not included in the models, and to the: influence of heat release on turbulence structure near the flame base. (C) 1999 by The Combustion Institute. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Def Sci & Technol Org, Aeronaut & Maritime Res Labs, Melbourne, Vic 3001, Australia. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Univ Sydney, Dept Mech Engn, Sydney, NSW 2006, Australia. RP Barlow, RS (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 40 TC 81 Z9 84 U1 1 U2 9 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 APR PY 1999 VL 117 IS 1-2 BP 4 EP 31 DI 10.1016/S0010-2180(98)00071-6 PG 28 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 162UX UT WOS:000078366200002 ER PT J AU Wong, ASM Hon, YC Li, TS Chung, SL Kansa, EJ AF Wong, ASM Hon, YC Li, TS Chung, SL Kansa, EJ TI Multizone decomposition for simulation of time-dependent problems using the multiquadric scheme SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE multizone; decomposition; hydrodynamics equation; multiquadric ID PARTIAL-DIFFERENTIAL EQUATIONS; COMPUTATIONAL FLUID-DYNAMICS; DATA APPROXIMATION SCHEME; SCATTERED DATA; INTERPOLATION AB This paper discusses the application of the multizone decomposition technique with multiquadric scheme for the numerical solutions of a time-dependent problem. The construction of the multizone algorithm is based on a domain decomposition technique to subdivide the global region into a number of finite subdomains. The reduction of ill-conditioning and the improvement of the computational efficiency can be achieved with a smaller resulting matrix on each subdomain. The proposed scheme is applied to a hypothetical linear two-dimensional hydrodynamic model as well as a real-life nonlinear two-dimensional hydrodynamic model in the Tolo Harbour of Hong Kong to simulate the water flow circulation patterns. To illustrate the computational efficiency and accuracy of the technique, the numerical results are compared with those solutions obtained from the same problem using a single domain multiquadric scheme. The computational efficiency of the multizone technique is improved substantially with faster convergence without significant degradation in accuracy. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 City Univ Hong Kong, Dept Math, Hong Kong, Hong Kong. Open Univ, Kowloon, Hong Kong. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Wong, ASM (reprint author), City Univ Hong Kong, Dept Math, Hong Kong, Hong Kong. OI Hon, Benny/0000-0001-5224-6238 NR 16 TC 48 Z9 48 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD APR PY 1999 VL 37 IS 8 BP 23 EP 43 DI 10.1016/S0898-1221(99)00098-X PG 21 WC Mathematics, Applied SC Mathematics GA 182DG UT WOS:000079482800003 ER PT J AU With, KA King, AW AF With, KA King, AW TI Extinction thresholds for species in fractal landscapes SO CONSERVATION BIOLOGY LA English DT Article ID NORTHERN SPOTTED OWL; HABITAT FRAGMENTATION; METAPOPULATION DYNAMICS; CONSERVATION BIOLOGY; DEMOGRAPHIC-MODELS; POPULATION; DISPERSAL; VIABILITY AB Predicting species' responses to habitat loss and fragmentation is one of the greatest challenges facing conservation biologists, particularly if extinction is a threshold phenomenon. Extinction thresholds are abrupt declines in the patch occupancy of a metapopulation across a narrow range of habitat loss. Metapopulation-type models have been used to predict extinction thresholds for endangered populations. These models often make simplifying assumptions about the distribution of habitat (random) and the search for suitable habitat sites (random dispersal). We relaxed these two assumptions in a modeling approach that combines a metapopulation model with neutral landscape models of fractal habitat distributions. Dispersal success for suitable, unoccupied sites was higher on fractal landscapes for nearest-neighbor dispersers (moving through adjacent cells of the landscape) than for dispersers searching at random (random distance and direction between steps) on random landscapes. Consequently, species either did not suffer extinction thresholds or extinction thresholds occurred later, at lower levels of habitat abundance, than predicted previously. The exception is for species with limited demographic potential, owing to low reproductive output (R-o' = 1.01), in which extinction thresholds occurred sooner than on random landscapes in all but the most clumped fractal landscapes (H = 1.0). Furthermore, the threshold was more precipitous for these species. Many species of conservation concern have limited demographic potential, and these species may be at greater risk from habitat loss and fragmentation than previously suspected. C1 Bowling Green State Univ, Dept Biol Sci, Bowling Green, OH 43403 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP With, KA (reprint author), Bowling Green State Univ, Dept Biol Sci, Bowling Green, OH 43403 USA. RI With, Kimberly/J-5124-2014 OI With, Kimberly/0000-0001-5570-1515 NR 42 TC 214 Z9 228 U1 7 U2 52 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD APR PY 1999 VL 13 IS 2 BP 314 EP 326 DI 10.1046/j.1523-1739.1999.013002314.x PG 13 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 181YX UT WOS:000079472000015 ER PT J AU Krukpe, WF AF Krukpe, WF TI New laser materials for diode pumped solid state lasers SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID OPTICAL-PROPERTIES; WAVE-GUIDE; CRYSTALS; GROWTH; PERFORMANCE; KGD(WO4)(2); OPERATION; FIBERS; IONS; YB3+ AB Ytterbium (Yb3+) doped solid state lasers (e.g. Yb:YAG), pumped with InGaAs laser diodes, have been intensively and successfully developed recently. A search is in progress for novel ytterbium doped crystals possessing properties superior to known Yb doped gain media, or with properties enabling of Yb lasers with new capabilities. Several such materials have been identified and characterized in the past year. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Laser Programs Directorate, Livermore, CA 94550 USA. RP Lawrence Livermore Natl Lab, Laser Programs Directorate, 7000 East Ave, Livermore, CA 94550 USA. EM krupke1@llnl.gov NR 24 TC 9 Z9 9 U1 3 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-0286 EI 1879-0348 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD APR PY 1999 VL 4 IS 2 BP 197 EP 201 DI 10.1016/S1359-0286(99)00003-0 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 206CL UT WOS:000080858800012 ER PT J AU Fischer, D Eisenberg, D AF Fischer, D Eisenberg, D TI Predicting structures for genome proteins SO CURRENT OPINION IN STRUCTURAL BIOLOGY LA English DT Review ID MYCOPLASMA-GENITALIUM PROTEINS; FOLDS AB Assigning three-dimensional protein folds to genome sequences is essential to understanding protein function. Although experimental three-dimensional structures are currently available for only a very small fraction of these sequences, computational fold assignment is able to assign folds to 20-30% of the sequences in various genomes. This percentage varies depending on the particular organism under analysis, on the sensitivities of the methods used and on the number of experimental structures available at the time the assignment is carried out. The fraction of assignable sequences is currently increasing at an annual rate of roughly 18%. If this rate is sustained throughout the coming years, three-dimensional computational models for more than half of the genome sequences may be available by the year 2003. C1 Fac Nat Sci, Dept Math & Comp Sci, IL-84015 Beer Sheva, Israel. Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Inst Mol Biol, Los Angeles, CA 90095 USA. RP Fac Nat Sci, Dept Math & Comp Sci, IL-84015 Beer Sheva, Israel. EM dfischer@cs.bgu.ac.il; david@mbi.ucla.edu NR 19 TC 40 Z9 40 U1 0 U2 0 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0959-440X EI 1879-033X J9 CURR OPIN STRUC BIOL JI Curr. Opin. Struct. Biol. PD APR PY 1999 VL 9 IS 2 BP 208 EP 211 DI 10.1016/S0959-440X(99)80029-3 PG 4 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 282LP UT WOS:000085219800009 PM 10322219 ER PT J AU Nolan, JP Lauer, S Prossnitz, ER Sklar, LA AF Nolan, JP Lauer, S Prossnitz, ER Sklar, LA TI Flow cytometry: a versatile tool for all phases of drug discovery SO DRUG DISCOVERY TODAY LA English DT Review ID GREEN FLUORESCENT PROTEIN; HUMAN FLAP ENDONUCLEASE-1; MISMATCH BINDING-PROTEIN; MUTATION DETECTION; RECEPTOR; LIFETIME; CELLS; MUTS; DNA AB The applications of flow cytometry are being extended beyond cells into molecular interactions and genomic analyses. The authors explain how instrumentation and reagent development are combining to improve flow cytometric throughput by orders of magnitude beyond that possible just a few years ago, such that the combination of sensitivity, throughput and versatility makes flow cytometry an analytical platform with applications at all stages of drug discovery. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ New Mexico, Sch Med, Dept Pathol, Albuquerque, NM 87131 USA. RP Nolan, JP (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, LS-5,M-888, Los Alamos, NM 87545 USA. EM nolan@telomere.lanl.gov RI Prossnitz, Eric/B-4543-2008 NR 49 TC 48 Z9 49 U1 1 U2 10 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-6446 J9 DRUG DISCOV TODAY JI Drug Discov. Today PD APR PY 1999 VL 4 IS 4 BP 173 EP 180 DI 10.1016/S1359-6446(99)01320-3 PG 8 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 180WL UT WOS:000079408100006 ER PT J AU Huston, MA AF Huston, MA TI Microcosm experiments have limited relevance for community and ecosystem ecology: Synthesis of comments SO ECOLOGY LA English DT Article C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Civil & Environm Engn, Knoxville, TN 37996 USA. RP Huston, MA (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Huston, Michael/B-1434-2009 OI Huston, Michael/0000-0001-9513-1166 NR 0 TC 38 Z9 40 U1 1 U2 24 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA SN 0012-9658 J9 ECOLOGY JI Ecology PD APR PY 1999 VL 80 IS 3 BP 1088 EP 1089 DI 10.1890/0012-9658(1999)080[1088:MEHLRF]2.0.CO;2 PG 2 WC Ecology SC Environmental Sciences & Ecology GA 228UP UT WOS:000082154300032 ER PT J AU Yang, XQ Sun, X Lee, SJ McBreen, J Mukerjee, S Daroux, ML Xing, XK AF Yang, XQ Sun, X Lee, SJ McBreen, J Mukerjee, S Daroux, ML Xing, XK TI In situ synchrotron X-ray diffraction studies of the phase transitions in LixMn2O4 cathode materials SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID LIMN2O4; LITHIUM; INSERTION; CELLS AB In situ X-ray diffraction studies of LixMn2O4 spinel cathode materials during charge- discharge cycling were carried out using a synchrotron as the X-ray source. Lithium-rich (x = 1.03- 1.06) spinel materials, obtained from two different sources, were studied. Three cubic phases with different lattice constants were observed during charge-discharge cycles in all of the samples when a sufficiently low charge-discharge rate (less than or equal to C/10) was used. There were two regions of two-phase coexistence, which indicates that both phase transitions are first order. The separation of the Bragg peaks representing these three phases varied from sample to sample and also depended on the charge-discharge rate. These results show that the deintercalation of lithium in lithium-rich spinel cathode materials proceeds through a series of phase transitions from a lithium-rich phase to a lithium-poor phase and finally to a lambda-MnO2-like cubic phase, rather than through a continuous lattice constant contraction in a single phase. (C) 1999 The Electrochemical Society. S1099- 0062( 98) 11- 078- 7. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Northeastern Univ, Dept Chem, Boston, MA 02115 USA. Gould Elect Inc, Eastlake, OH 44095 USA. RP Yang, XQ (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 10 TC 71 Z9 75 U1 1 U2 29 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 APR PY 1999 VL 2 IS 4 BP 157 EP 160 DI 10.1149/1.1390768 PG 4 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 185ZC UT WOS:000079700700001 ER PT J AU Balasubramanian, M Melendres, CA AF Balasubramanian, M Melendres, CA TI Selective site occupancy exhibited by Cr3+ and Cr6+ incorporated into electrochemically deposited nickel hydroxide films SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID ABSORPTION FINE-STRUCTURE; SPECTRA; SPECTROSCOPY; ELECTRODES AB We have utilized extended X-ray absorption fine structure (EXAFS) spectroscopy to investigate the site occupancy and local structure of Cr3+ and Cr6+ ions incorporated into electrodeposited alpha-Ni(OH)(2) films. The films were prepared by codeposition of Cr and Ni at constant cathodic current from aqueous solutions of nickel nitrate, chromium nitrate, and potassium chromate. EXAFS measurements show that in films produced from Ni2+ and Cr3+ solution, Cr3+ is incorporated into Ni lattice sites in alpha-Ni(OH)(2). On the other hand, cathodic codeposition of Cr6+ and Ni2+ results in CrO42- in interlamellar sites as well as sorbed on the surface of alpha-Ni(OH)(2). These results are of significance in a number of technological areas, e.g., batteries, corrosion protection, environmental speciation, and remediation. (C) 1999 The Electrochemical Society. S1099-0062(98)06-015-5. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Balasubramanian, M (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 21 TC 11 Z9 11 U1 2 U2 4 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 APR PY 1999 VL 2 IS 4 BP 167 EP 169 DI 10.1149/1.1390771 PG 3 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 185ZC UT WOS:000079700700004 ER PT J AU Feustel, HE AF Feustel, HE TI COMIS - an international multizone air-flow and contaminant transport model SO ENERGY AND BUILDINGS LA English DT Article DE multizone; air flow; modeling; model evaluation AB A number of interzonal models have been developed to calculate air flows and pollutant transport mechanisms in both single and multizone buildings. A recent development in multizone air-flow modeling, the COMIS model, has a number of capabilities that go beyond previous models, much as COMIS can be used as either a stand-alone air-flow model with input and output features or as an infiltration module for thermal building simulation programs. COMIS was designed during a 12 month workshop at Lawrence Berkeley National Laboratory (LBNL) in 1988-1989. In 1990, the Executive Committee of the International Energy Agency's Energy Conservation in Buildings and Community Systems program created a working group on multizone air-flow modeling, which continued work on COMIS. The group's objectives were to study physical phenomena causing air flow and pollutant (e.g., moisture) transport in multizone buildings, develop numerical modules to be integrated in the previously designed multizone air flow modeling system, and evaluate the computer code. The working group supported by nine nations, officially finished in late 1997 with the release of IISiBat/COMIS 3.0, which contains the documented simulation program COMIS, the user interface IISiBat, and reports describing the evaluation exercise. This paper serves as an introduction for the other publications included in this Special Issue. Published by Elsevier Science S.A. C1 Lawrence Berkeley Lab, Environm Energy Technol Div, Indoor Environm Dept, Berkeley, CA 94720 USA. RP Feustel, HE (reprint author), Lawrence Berkeley Lab, Environm Energy Technol Div, Indoor Environm Dept, Bldg 90,Room 3074, Berkeley, CA 94720 USA. NR 53 TC 91 Z9 92 U1 5 U2 14 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7788 J9 ENERG BUILDINGS JI Energy Build. PD APR PY 1999 VL 30 IS 1 BP 3 EP 18 DI 10.1016/S0378-7788(98)00043-7 PG 16 WC Construction & Building Technology; Energy & Fuels; Engineering, Civil SC Construction & Building Technology; Energy & Fuels; Engineering GA 182FG UT WOS:000079487800002 ER PT J AU Hughes, SD AF Hughes, SD TI Critical masses: Opposition to nuclear power in California, 1958-1978. SO ENVIRONMENTAL HISTORY LA English DT Book Review C1 Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hughes, SD (reprint author), Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 USA SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 1999 VL 4 IS 2 BP 267 EP 270 DI 10.2307/3985306 PG 4 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA 212YM UT WOS:000081245300007 ER PT J AU Hughes, SD AF Hughes, SD TI Licensed to kill? The nuclear regulatory commission and the Shoreham power plant. SO ENVIRONMENTAL HISTORY LA English DT Book Review C1 Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hughes, SD (reprint author), Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 USA SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 1999 VL 4 IS 2 BP 267 EP 270 DI 10.2307/3985306 PG 4 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA 212YM UT WOS:000081245300008 ER PT J AU Hughes, SD AF Hughes, SD TI Nuclear politics in America: A history and theory of government regulation. SO ENVIRONMENTAL HISTORY LA English DT Book Review C1 Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hughes, SD (reprint author), Univ New Mexico, UNM Inst Publ Policy, Albuquerque, NM 87131 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 USA SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 1999 VL 4 IS 2 BP 267 EP 270 DI 10.2307/3985306 PG 4 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA 212YM UT WOS:000081245300006 ER PT J AU Streets, DG Hedayat, L Carmichael, GR Arndt, RL Carter, LD AF Streets, DG Hedayat, L Carmichael, GR Arndt, RL Carter, LD TI Potential for advanced technology to improve air quality and human health in Shanghai SO ENVIRONMENTAL MANAGEMENT LA English DT Article DE coal; China; Shanghai; sulfur dioxide; air quality; health effects ID CHINA; EMISSIONS; POLLUTION; DEPOSITION; SULFUR; ASIA AB Air quality in most Asian cities is poor and getting worse. It will soon become impossible to sustain population, economic, and industrial growth without severe deterioration of the atmospheric environment. This paper addresses the city of Shanghai, the air-quality problems it faces over the next 30 years, and the potential of advanced technology to alleviate these problems. Population, energy consumption, and emission profiles are developed for the city at 0.1 degrees X 0.1 degrees resolution and extrapolated from 1990 to 2020 using sector-specific economic growth factors. Within the context of the RAINS-Asia model, eight technology scenarios are examined for their effects on ambient concentrations of sulfur dioxide and sulfate and their emission control costs. Without new control measures, it is projected that the number of people exposed to sulfur dioxide concentrations in excess of guidelines established by the World Health Organization will rise from 650,000 in 1990 to more than 14 million in 2020. It is apparent that efforts to reduce emissions are likely to have significant health benefits, measured in terms of the cost of reducing the number of people exposed to concentrations in excess of the guidelines ($10-50 annually per person protected). Focusing efforts on the control of new coal-fired power plants and industrial facilities has the greatest benefit. However, none of the scenarios examined is alone capable of arresting the increases in emissions, concentrations, and population exposure. It is concluded that combinations of stringent scenarios in several sectors will be necessary to stabilize the situation, at a potential cost of $500 million annually by the year 2020. C1 Argonne Natl Lab, Decis & Informat Sci Div, Argonne, IL 60439 USA. Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. US DOE, Off Fossil Energy, Washington, DC 20585 USA. RP Streets, DG (reprint author), Argonne Natl Lab, Decis & Informat Sci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Streets, David/0000-0002-0223-1350 NR 25 TC 21 Z9 22 U1 0 U2 3 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 APR PY 1999 VL 23 IS 3 BP 279 EP 295 DI 10.1007/s002679900186 PG 17 WC Environmental Sciences SC Environmental Sciences & Ecology GA 171HU UT WOS:000078858200001 ER PT J AU Bontha, JR Kaplan, DI AF Bontha, JR Kaplan, DI TI Immobilization or recovery of chlorinated hydrocarbons from contaminated groundwater using clathrate hydrates: A proof-of-concept SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB The objective of this study was to evaluate whether the formation of solid clathrate hydrates by certain chlorinated hydrocarbon compounds and water would be amenable to in situ immobilization and ex situ recovery of these contaminants from groundwater. Using help gases to enhance the formation of the solids, the melting points of clathrate hydrates of CCl4 1,1-DCE, PCE, and TCE were measured at 1 atm pressure. CCl4 hydrates had melting points between 16 and 20 degrees C; 1,1-DCE hydrates had lower melting points of between 11 and 13 degrees C. TCE and PCE hydrates could not be formed unless crystallizing seed material was introduced into the system. Concentrations of CCl4 and 1,1-DCE in the hydrate phase and the aqueous phase after hydrate formation were determined from experiments in which the chlorinated hydrocarbon compounds existed as a separate dense nonaqueous phase liquid (DNAPL) or as dissolved species in water. Enrichment factors (C-H/C-A, where C is the concentration of the organic in the hydrate [H] and aqueous [A] phase) were between 200 and 500 for 1,1-DCE and CCl4, respectively. These experiments provided a proof-of-concept suggesting that the in situ immobilization or ex situ recovery of some common hydrophobic groundwater contaminants may be possible in a wide range of subsurface environments. C1 Pacific NW Natl Lab, Richland, WA 99325 USA. RP Bontha, JR (reprint author), Pacific NW Natl Lab, POB 999,Mail Stop P7-43, Richland, WA 99325 USA. EM J.R.Bontha@pnl.gov NR 14 TC 7 Z9 7 U1 2 U2 5 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 APR 1 PY 1999 VL 33 IS 7 BP 1051 EP 1055 DI 10.1021/es9803862 PG 5 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 183FG UT WOS:000079543100029 ER PT J AU Vancheeswaran, S Halden, RU Williamson, KJ Ingle, JD Semprini, L AF Vancheeswaran, S Halden, RU Williamson, KJ Ingle, JD Semprini, L TI Abiotic and biological transformation of tetraalkoxysilanes and trichloroethene/cis-1,2-dichloroethene cometabolism driven by tetrabutoxysilane-degrading microorganisms SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID REDUCTIVE DECHLORINATION; CEPACIA G4; TRICHLOROETHYLENE; TETRACHLOROETHENE; DEGRADATION; HYDROGEN; TOLUENE AB Attenuation of silicon-based organic compounds (tetraalkoxysilanes) by abiotic hydrolysis and biological mineralization was investigated. At Lawrence Livermore National Laboratory site 300, tetraalkoxysilanes are present along with trichloroethene (TCE) as subsurface contaminants. Under abiotic conditions, the alkoxysilanes such as tetrabutoxysilane (TBOS) and tetrakis(2-ethylbutoxy)silane (TKEBS) hydrolyze to l-butanol and 2-ethylbutanol, respectively, and silicic acid. The rates of hydrolysis of TBOS and TKEBS were determined to evaluate the significance of the hydrolysis reaction in the attenuation process, and typical rates at pH 7, 30 degrees C, and 28 mu mol/L initial concentration were 0.32 and 0.048 mu mol/L/day, respectively. The TBOS hydrolysis reaction was observed to be acid- and base-catalyzed and independent of temperature from 15 to 30 degrees C. All hydrolysis experiments were conducted at concentrations above the solubility limit of TBOS and TKEBS, and the rate of hydrolysis increased with concentration of TBOS or TKEBS. An aerobic microbial culture from the local wastewater treatment plant that could grow and mineralize the alkoxysilanes was enriched. The enriched culture rapidly hydrolyzed TBOS and TKEBS and grew on the hydrolysis products. The microorganisms grown on TBOS cometabolized TCE and cis-1,2-dichloroethene (c-DCE). TCE and c-DCE degradation was inhibited by acetylene, indicating that a monooxygenase was involved in the cometabolism process. Acetylene did not inhibit the hydrolysis of TBOS or the utilization of l-butanol, indicating that the above monooxygenase enzyme was not involved in the degradation of TBOS. C1 Oregon State Univ, Dept Civil Construct & Environm Engn, Corvallis, OR 97331 USA. Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA. Lawrence Livermore Natl Lab, Livermore, CA USA. RP Semprini, L (reprint author), Oregon State Univ, Dept Civil Construct & Environm Engn, Corvallis, OR 97331 USA. EM semprinl@ccmail.orst.edu RI Halden, Rolf/F-9562-2010 OI Halden, Rolf/0000-0001-5232-7361 NR 21 TC 11 Z9 11 U1 0 U2 11 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 APR 1 PY 1999 VL 33 IS 7 BP 1077 EP 1085 DI 10.1021/es981021k PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 183FG UT WOS:000079543100034 ER PT J AU Cook, RB Suter, GW Sain, ER AF Cook, RB Suter, GW Sain, ER TI Ecological risk assessment in a large river-reservoir: 1. Introduction and background SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ecological risk assessment; clinch river; radionuclide contaminants; metal contaminants; organic contaminants ID HAZARDOUS-WASTE SITES AB The U.S. Department of Energy initiated a remedial investigation of the Clinch River/Poplar Creek system Superfund Site in 1989. This site, located in eastern Tennessee near Oak Ridge, consists of 70 river kilometers and 40 km(2) of surface area. The purpose of this study was to evaluate the nature and extent of contamination, perform an ecological and human health risk assessment, and evaluate possible remedial alternatives. This introductory article summarizes the environmental setting, the contamination history, and the study approach and provides some general results of the site characterization. Subsequent papers in this series describe the ecological risks to fish, piscivorous and insectivorous wildlife, and benthic invertebrates. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Cook, RB (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. OI Cook, Robert/0000-0001-7393-7302 NR 36 TC 33 Z9 42 U1 0 U2 12 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 APR PY 1999 VL 18 IS 4 BP 581 EP 588 DI 10.1897/1551-5028(1999)018<0581:ERAIAL>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000002 ER PT J AU Suter, GW Barnthouse, LW Efroymson, RA Jager, H AF Suter, GW Barnthouse, LW Efroymson, RA Jager, H TI Ecological risk assessment in a large river-reservoir: 2. Fish community SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ecological risk assessment; weight of evidence; fish; ecoepidemiology ID TOXIC CONTAMINANTS; POPULATIONS AB This paper summarizes the assessment of risks to fishes in the Clinch River Operable Unit due to contaminants released by the U.S. Department of Energy's activities on its Oak Ridge Reservation in Tennessee. This paper focuses on the most contaminated area, the Poplar Creek (PC) embayment. The assessment is of interest because of its use of five distinct lines of evidence: fish community surveys, fish body burdens, toxicity tests of ambient waters, suborganismal bioindicators, and single chemical toxicity tests. None of these lines of evidence provided unambiguous evidence of a significant risk, but the surveys indicated that the fish community in PC was depauperate, polychlorinated biphenyl body burdens may have been at toxic levels in catfish, one of the three tests of ambient water showed clear toxicity, some of the indicators were indicative of toxic effects, and concentrations that have been toxic in the laboratory were detected periodically. Interpretation was further complicated by upstream contamination of both the Clinch River and PC. The risk characterization was performed by evaluating each line of evidence separately and then weighing the evidence using an ecoepidemiological approach. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Suter, GW (reprint author), US EPA Facil, MS 117,26 W Martin Luther King Dr, Cincinnati, OH 45268 USA. EM suter.glenn@epamail.epa.gov OI Jager, Henriette/0000-0003-4253-533X; Efroymson, Rebecca/0000-0002-3190-880X NR 24 TC 21 Z9 24 U1 0 U2 9 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 APR PY 1999 VL 18 IS 4 BP 589 EP 598 DI 10.1897/1551-5028(1999)018<0589:ERAIAL>2.3.CO;2 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000003 ER PT J AU Jones, DS Barnthouse, LW Suter, GW Efroymson, RA Field, JM Beauchamp, JJ AF Jones, DS Barnthouse, LW Suter, GW Efroymson, RA Field, JM Beauchamp, JJ TI Ecological risk assessment in a large river-reservoir: 3. Benthic invertebrates SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ecological risk assessment; benthic invertebrates; sediment; metals; organic chemicals ID SEDIMENT AB The sediments of Poplar Creek and the Clinch River are contaminated with a wide variety of chemicals, including heavy metals, polycyclic aromatic hydrocarbons, and PCBs. Sources include the U.S. Department of Energy's Oak Ridge Reservation as well as both known and unidentified upstream activities. We investigated the risks to benthic invertebrates posed by chemicals in these sediments as part of a comprehensive ecological risk assessment performed to support Superfund clean-up decisions. Poplar Creek was the only river reach for which significant risks were determined. This conclusion was based on several lines of reasoning: sediment-associated organisms at most sites were exposed to levels of several contaminants that have been observed to be toxic; the biosurvey results show a greater than 20% reduction relative to reference sites in taxa richness and abundance; the statistical analysis of the physical, contaminant, and biosurvey data did not exclude contaminants as possible causal factors; and the sediment toxicity tests were too ambiguous to definitively exclude impacts in this reach. This assessment demonstrates the importance of collecting biological data, including sediment toxicity tests and biological surveys; statistically analyzing the relationships of chemicals, physical variables, and measured effects (e.g., toxicity or benthic invertebrate densities); and using sediment chemical and effects distributions in addition to point estimates of exposure and screening benchmarks. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Dept Math & Comp Sci, Oak Ridge, TN 37831 USA. RP Jones, DS (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. OI Efroymson, Rebecca/0000-0002-3190-880X NR 21 TC 32 Z9 38 U1 2 U2 10 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 APR PY 1999 VL 18 IS 4 BP 599 EP 609 DI 10.1897/1551-5028(1999)018<0599:ERAIAL>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000004 ER PT J AU Sample, BE Suter, GW AF Sample, BE Suter, GW TI Ecological risk assessment in a large river-reservoir: 4. Piscivorous wildlife SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ecological risk assessment; wildlife; mercury; polychlorinated biphenyls; weight of evidence ID FORSTER TERNS; MINK; MERCURY; REPRODUCTION; FISH; BAY AB Over 50 years of operations of facilities on the Oak Ridge Reservation (ORR), Tennessee, has resulted in the release of contaminants into the water, sediment, and biota of the Clinch River and Poplar Creek, downstream of the ORR. An iterative, weight-of-evidence approach was employed to assess risks these contaminants present to four piscivorous wildlife species (osprey [Pandion haliaetus], great blue heron [Ardea herodias], mink [Mustela vison], and river otter [Lutra canadensis]) in the Clinch River/Poplar Creek (CR/PC) watershed. Available data consisted of literature-derived NOAELs and LOAELs, field surveys. and toxicity tests. Contaminants of potential ecological concern (COPECs) were identified by comparing point estimates of exposure to NOAELs and included mercury and PCBs. Exposure to COPECs was reestimated using Monte Carlo methods, first at individual locations, then over ecologically relevant spatial scales. These exposure distributions were compared to LOAELs. Estimated exposure for mink was not sufficient to present a risk from any COPEC. Mercury and PCBs presented a significant risk to river otter at one location each. Exposure of osprey and great blue herons to mercury represented a significant risk at one and two locations, respectively. Field surveys of heron rookeries and osprey nests indicated no adverse effects on reproduction. Mink fed fish from the Clinch River displayed reduced reproduction only in the most contaminated of five toxicity test diets; this reduction was not statistically significant, however. The maximum mercury and PCB exposures estimated for mink along the Clinch River were significantly lower than the toxicity test exposures associated with adverse effects The weight of evidence indicates that contaminants from the ORR do not present a risk to mink, great blue heron, or osprey along the Clinch River; river otter, however, may be at risk from mercury and PCBs. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Sample, BE (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 33 TC 35 Z9 40 U1 2 U2 15 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 APR PY 1999 VL 18 IS 4 BP 610 EP 620 DI 10.1897/1551-5028(1999)018<0610:ERAIAL>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000005 ER PT J AU Baron, LA Sample, BE Suter, GW AF Baron, LA Sample, BE Suter, GW TI Ecological risk assessment in a large river-reservoir: 5. Aerial insectivorous wildlife SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ecological risk assessment; aerial insectivores; Monte Carlo; mercury; polychlorinated biphenyls ID POLYCHLORINATED-BIPHENYLS; TACHYCINETA BICOLOR; MYOTIS-LUCIFUGUS; TREE SWALLOWS; BROWN BAT; METHYLMERCURY; MERCURY AB Risks to aerial insectivores (e.g., rough-winged swallows, little brown bats, and endangered gray bats) were assessed for the remedial investigation of the Clinch River/Poplar Creek (CR/PC) system. Adult mayflies and sediment were collected from three locations and analyzed for contaminants. Sediment-to-mayfly contaminant uptake factors were generated from these data and used to estimate contaminant concentrations in mayflies from 13 additional locations. Contaminants of potential ecological concern (COPECs) were identified by comparing exposure estimates generated using point estimates of parameter values to NOAELs. To incorporate the variation in exposure parameters and to provide a better estimate of the potential exposure, the exposure model was recalculated using Monte Carlo methods. The potential for adverse effects was estimated based on the comparison of exposure distribution and the LOAEL. The results of this assessment suggested that population-level effects to rough-winged swallows and little brown bats are considered unlikely. However, because gray bats are endangered, effects on individuals may be significant from foraging in limited subreaches of the CR/PC system. This assessment illustrates the advantage of an iterative approach to ecological risk assessments, using fewer conservative assumptions and more realistic modeling of exposure. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Baron, LA (reprint author), McLaren Hart, ChemRisk Div, 25 Independence Blvd, Warren, NJ 07059 USA. NR 34 TC 10 Z9 14 U1 6 U2 22 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 APR PY 1999 VL 18 IS 4 BP 621 EP 627 DI 10.1897/1551-5028(1999)018<0621:ERAIAL>2.3.CO;2 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000006 ER PT J AU Adams, SM Bevelhimer, MS Greeley, MS Levine, DA Teh, SJ AF Adams, SM Bevelhimer, MS Greeley, MS Levine, DA Teh, SJ TI Ecological risk assessment in a large river-reservoir: 6. Bioindicators of fish population health SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE bioindicators; fish health; integrated responses; contaminant effects ID RAINBOW-TROUT; POLYCHLORINATED-BIPHENYLS; CHANNA-PUNCTATUS; MERCURY; LIVER; RESPONSES; EXPOSURE; AMMONIA; STREAM; ELSAN AB Spatial distribution of contaminants in the sediments and biota of a large reservoir ecosystem were related to a variety of biological responses in fish populations and communities to determine possible relationships between contaminant loading in the environment and fish health. Much of the contaminant inventory in the Clinch River/Watts Bar Reservoir (CR/WBR) system has originated from three U.S. Department of Energy facilities on the Oak Ridge Reservation, which borders this system in its upper reaches. Fish sampled from areas of the CR/WBR system with the highest levels of contaminants in the sediments and biota, primarily mercury and PCBs, had the most dramatic bioindicator responses. The major changes observed were induction of detoxification enzymes, organ dysfunction, increased frequency of histopathological lesions, impaired reproduction, and reduced fish community integrity. Mercury, the dominant contaminant, displayed a decreasing concentration gradient from the: upper reaches of Poplar Creek to the lower Clinch River, which was consistent with a downstream gradient in several of the biological responses. A multivariate analysis using all of the individual fish health responses at each sire in a discriminant analysis procedure also revealed a downstream gradient in integrated fish health. In Poplar Creek where contaminant concentrations were the highest, statistical correlations were observed between individual bioindicator responses such as contaminant exposure indicators. organ dysfunction, histopathological damage, and reproductive impairment. Relationships between contaminant Loading and fish community indices such as species richness and relative abundance, however, were more difficult to establish in Poplar Creek because of the possible dominating influence of food and habitat availability on fish community dynamics. Using a suite of bioindicators that encompass a range of levels of biological organization and response-sensitivity scales improves the probability of identifying cause (contaminant) and effect (biological response) and helps in distinguishing between natural and anthropogenic sources of stress in aquatic ecosystems. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Calif Davis, Sch Vet Med, Dept Anat Physiol & Cell Biol, Davis, CA 95616 USA. RP Adams, SM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. EM sma@ornl.gov RI Greeley, Mark/D-2330-2016 OI Greeley, Mark/0000-0002-6088-5942 NR 43 TC 55 Z9 61 U1 0 U2 30 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0730-7268 EI 1552-8618 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD APR PY 1999 VL 18 IS 4 BP 628 EP 640 DI 10.1897/1551-5028(1999)018<0628:ERAIAL>2.3.CO;2 PG 13 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 178CJ UT WOS:000079222000007 ER PT J AU Mitchell, RAC Black, CR Burkart, S Burke, JI Donnelly, A de Temmmerman, L Fangmeier, A Mulholland, BJ Theobald, JC van Oijen, M AF Mitchell, RAC Black, CR Burkart, S Burke, JI Donnelly, A de Temmmerman, L Fangmeier, A Mulholland, BJ Theobald, JC van Oijen, M TI Photosynthetic responses in spring wheat grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment 'ESPACE-wheat' SO EUROPEAN JOURNAL OF AGRONOMY LA English DT Article DE carbon dioxide; open-top chambers; ozone; photosynthetic acclimation; Triticum aestivum ID RISING ATMOSPHERIC CO2; PRODUCTIVITY; TEMPERATURE; PROTEINS; PLANTS AB Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO2 concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO2 for a range of N application regimes, O-3 concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 mu mol mol(-1) CO2 at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO2 before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO2 after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO2 therefore appears to occur only slowly, consistent with a response to changes in sink-source relationships, rather than a direct response. Effect of elevated CO2 on stomatal conductance was much more variable between sites and treatments, but on average was decreased by similar to 10% at 650 compared with 350 mu mol mol(-1) CO2. Carboxylation capacity of flag leaves was decreased by growth at elevated O-3 both before and after anthesis, regardless of CO2 concentration. (C) 1999 Elsevier Science B.V. All rights reserved. C1 AFRC, Inst Arable Crops Res, Dept Physiol & Biochem, Harpenden AL5 2JQ, Herts, England. Univ Nottingham, Dept Physiol & Environm Sci, Loughborough LE12 5RD, Leics, England. Inst Prod & Ecotoxicol, Braunschweig, Germany. TEAGASC, Agr & Food Dev Author, Oak Pk Res Ctr, Carlow, Ireland. Univ Dublin Trinity Coll, Dept Bot, Dublin 2, Ireland. Vet & Agrochem Res Ctr, Tervuren, Belgium. Univ Giessen, Inst Plant Ecol, Giessen, Germany. Wageningen Univ Agr, Dept Theoret Prod Ecol, NL-6700 AK Wageningen, Netherlands. RP Mitchell, RAC (reprint author), AFRC, Inst Arable Crops Res, Dept Physiol & Biochem, Harpenden AL5 2JQ, Herts, England. RI Van Oijen, Marcel/K-2746-2012; OI Van Oijen, Marcel/0000-0003-4028-3626; Fangmeier, Andreas/0000-0003-3794-9466 NR 18 TC 26 Z9 28 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1161-0301 J9 EUR J AGRON JI Eur. J. Agron. PD APR PY 1999 VL 10 IS 3-4 BP 205 EP 214 DI 10.1016/S1161-0301(99)00010-6 PG 10 WC Agronomy SC Agriculture GA 212YD UT WOS:000081244500007 ER PT J AU Fangmeier, A De Temmerman, L Mortensen, L Kemp, K Burke, J Mitchell, R van Oijen, M Weigel, HJ AF Fangmeier, A De Temmerman, L Mortensen, L Kemp, K Burke, J Mitchell, R van Oijen, M Weigel, HJ TI Effects on nutrients and on grain quality in spring wheat crops grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment 'ESPACE-wheat' SO EUROPEAN JOURNAL OF AGRONOMY LA English DT Article DE CO2 enrichment; grain quality; nutrients; Triticum aestivum; tropospheric ozone ID RISING ATMOSPHERIC CO2; TRITICUM-AESTIVUM L; TOP FIELD CHAMBERS; SPRUCE PICEA-ABIES; TROPOSPHERIC OZONE; NORWAY SPRUCE; MINERAL-NUTRITION; LITTER QUALITY; CLIMATE CHANGE; AMBIENT AIR AB Nutrient element concentrations and grain quality were assessed in spring wheat grown under elevated CO2 concentrations and contrasting levels of tropospheric ozone at different nitrogen supply rates at several European sites. Carbon dioxide enrichment proved to affect nutrient concentrations in a complex manner, In green leaves, all elements (with exception of phosphorus and iron) decreased. In contrast, effects on the element composition of grains were restricted to reductions in nitrogen, calcium, sulphur and iron. Ozone exposure resulted in no significant effects on nutrient element concentrations in different tissues in the overall analysis. The nitrogen demand of green tissues was reduced due to CO2 enrichment as shown by reductions in the critical leaf nitrogen concentration and also enhanced nitrogen use efficiency. Reductions in the content of ribulose-bisphosphate carboxylase/oxygenase and repression of the photorespiratory pathway and reduced nitrogen allocation to enzymes driving the photosynthetic carbon oxidation cycle were chiefly responsible for this effect. Thus, nitrogen acquisition by the crop did not match carbon acquisition under CO2 enrichment, Since crop nitrogen uptake from the soil was already completed at anthesis, nitrogen allocated to the grain after anthesis originated from vegetative poors-causing grain nitrogen concentrations to decrease under CO2 enrichment (on average by 15% when CO2 concentrations increased from 360 to 680 mu mol mol(-1)). Correspondingly, grain quality was reduced by CO2 enrichment. The Zeleny value, Hagberg value and dry/wet gluten content decreased significantly with increasing [CO2]. Despite the beneficial impact of CO2 enrichment on growth and yield of C-3 cereal crops, declines in flour quality due to reduced nitrogen content are likely in a future, [CO2]-rich world. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Giessen, Inst Plant Ecol, D-35392 Giessen, Germany. Vet & Agrochem Res Tervuren, B-3080 Tervuren, Belgium. TEAGASC, Agr & Food Dev Author, Oak Pk Res Ctr, Carlow, Ireland. AFRC, Inst Arable Crops Res, Dept Biochem & Physiol, Harpenden AL5 2JQ, Herts, England. Wageningen Univ Agr, Dept Theoret Prod Ecol, NL-6700 AK Wageningen, Netherlands. FAL, Inst Prod & Ecotoxicol, D-38116 Braunschweig, Germany. RP Fangmeier, A (reprint author), Univ Giessen, Inst Plant Ecol, D-35392 Giessen, Germany. RI Van Oijen, Marcel/K-2746-2012; OI Van Oijen, Marcel/0000-0003-4028-3626; Fangmeier, Andreas/0000-0003-3794-9466 NR 63 TC 82 Z9 89 U1 5 U2 34 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1161-0301 J9 EUR J AGRON JI Eur. J. Agron. PD APR PY 1999 VL 10 IS 3-4 BP 215 EP 229 DI 10.1016/S1161-0301(99)00012-X PG 15 WC Agronomy SC Agriculture GA 212YD UT WOS:000081244500008 ER PT J AU Vogel, O Chakrawarthy, RS Dewald, A Petkov, P Jessen, K Gableske, J von Brentano, P Bazzacco, D Gizon, A Gizon, J Lunardi, S Napoli, DR Pavan, P Alvarez, CR Wiedenhover, I AF Vogel, O Chakrawarthy, RS Dewald, A Petkov, P Jessen, K Gableske, J von Brentano, P Bazzacco, D Gizon, A Gizon, J Lunardi, S Napoli, DR Pavan, P Alvarez, CR Wiedenhover, I TI High spin states in Ba-128 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID REGION; PROTON; BAND AB High spin states in Ba-128 have been investigated with the fusion-evaporation reaction Zr-96 (S-36, 4n)Ba-128 at a beam energy of 150 MeV with the GASP-spectrometer at INFN in Legnaro, Italy. The level scheme could be extended to higher spins and six-quasiparticle states have been observed. The deduced alignments are compared to the predictions of previously reported cranked shell model calculations. C1 Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany. Univ Grenoble 1, Inst Sci Nucl, F-38036 Grenoble, France. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Sez Padova, Padua, Italy. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Argonne Natl Lab, Argonne, IL 60439 USA. Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, BG-1784 Sofia, Bulgaria. RP Vogel, O (reprint author), Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany. RI Dewald, Alfred/O-5810-2015; Napoli, Daniel R./D-9863-2012 OI Napoli, Daniel R./0000-0002-8154-6958 NR 14 TC 16 Z9 16 U1 0 U2 2 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 APR PY 1999 VL 4 IS 4 BP 323 EP 325 DI 10.1007/s100500050238 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 192AC UT WOS:000080054400005 ER PT J AU Abele, A Adomeit, B Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Beuchert, K Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crede, V Crowe, KM Degener, T Djaoshvili, N von Dombrowski, S Doser, M Dunnweber, W Ehmanns, A Engelhardt, D Faessler, MA Giaritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammle, B Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Ludemann, J Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Ould-Saada, F Peters, K Pick, B Pietra, C Pinder, CN Ratajczak, M Regenfus, C Resag, S Rothel, W Schmidt, P Seibert, R Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, B AF Abele, A Adomeit, B Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Beuchert, K Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crede, V Crowe, KM Degener, T Djaoshvili, N von Dombrowski, S Doser, M Dunnweber, W Ehmanns, A Engelhardt, D Faessler, MA Giaritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammle, B Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Ludemann, J Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Ould-Saada, F Peters, K Pick, B Pietra, C Pinder, CN Ratajczak, M Regenfus, C Resag, S Rothel, W Schmidt, P Seibert, R Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, B CA CRYSTAL BARREL Collaboration TI Observation of resonances in the reaction (p)over-bar-p ->pi(0)eta eta at 1.94 GeV/c SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article AB Antiproton-proton annihilation into pi(o)eta eta has been studied with the Crystal Barrel spectrometer at CERN at an incident beam momentum of 1.94 GeV/c. The data were taken with a trigger requiring neutral final states. A new isovector state, the alpha(2)(1660) decaying to pi(o)eta, is observed. In the eta eta invariant mass region around 2.1 GeV/c(2), strong production of a heavy resonance is required, but our analysis does not distinguish between J(P) = 0(+), 2(+) and 4(+). The production of the fo(1500) in reactions in flight is also observed. C1 Univ Karlsruhe, D-76021 Karlsruhe, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Ruhr Univ Bochum, D-44788 Bochum, Germany. Univ Bonn, D-53115 Bonn, Germany. Hungarian Acad Sci, H-1525 Budapest, Hungary. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. CERN, CH-1211 Geneva, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Munich, D-85748 Munich, Germany. LPNHE Paris 6, F-75252 Paris, France. LPNHE Paris 7, F-75252 Paris, France. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Ctr Rech Nucl, F-67037 Strasbourg, France. Univ Zurich, CH-8057 Zurich, Switzerland. RP Abele, A (reprint author), Univ Karlsruhe, D-76021 Karlsruhe, Germany. RI Peters, Klaus/C-2728-2008; Meyer, Curtis/L-3488-2014 OI Peters, Klaus/0000-0001-7133-0662; Meyer, Curtis/0000-0001-7599-3973 NR 13 TC 27 Z9 27 U1 0 U2 2 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 APR PY 1999 VL 8 IS 1 BP 67 EP 79 DI 10.1007/s100520050445 PG 13 WC Physics, Particles & Fields SC Physics GA 189EE UT WOS:000079890600005 ER PT J AU Hamza, AV Schenkel, T Barnes, AV AF Hamza, AV Schenkel, T Barnes, AV TI Dependence of cluster ion emission from uranium oxide surfaces on the charge state of the incident slow highly charged ion SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID SPUTTERED METAL-CLUSTERS; MOLECULAR-DYNAMICS; MASS-DISTRIBUTION; ENERGY; BOMBARDMENT; MECHANISM; MODEL AB The cluster ion yields and cluster ion distribution for highly charged ion sputtering have been measured for a uranium oxide target for Xe44+, Au-63,Au-66,Au-69+ and Th75+ incident ions. The cluster yields exhibit a power lan dependence on the cluster size with exponents increasing from -4 to -2.4 with increasing primary ion charge from 44+ to 75+. The power law exponent is also correlated with the total sputter yield. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Hamza, AV (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 27 TC 15 Z9 15 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD APR PY 1999 VL 6 IS 1 BP 83 EP 87 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 188UA UT WOS:000079865800010 ER PT J AU Ding, CHQ AF Ding, CHQ TI High Performance Fortran for practical scientific algorithms: An up-to-date evaluation SO FUTURE GENERATION COMPUTER SYSTEMS LA English DT Article DE HPF; distributed-memory architecture; parallel programming language; MPI; stencils computation; N-body problem; LU factorization; array redistribution; FFT AB A suite of High Performance Fortran (HPF) coding examples of practical scientific algorithms are examined in detail, with the idea that on these simple but non-trivial examples, we can fairly well understand issues related to different data distributions, different parallel constructs, and different programming styles (static Versus dynamic allocations). Coding examples include 2D stencils solution of PDEs, N-body problem, LU factorization, several vector/matrix library routines, 2D and 3D array redistribution. Performances of HPF codes are compared to hand-written Fortran codes with message passing libraries. From 1997 to 1998, HPF compilers are improved significantly such that HPF codes perform as well as Fortran+MPI codes for all the examples investigated here. However, many important peculiarities of HPF coding still exist. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. RP Ding, CHQ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. NR 6 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD APR PY 1999 VL 15 IS 3 BP 343 EP 352 DI 10.1016/S0167-739X(98)00079-X PG 10 WC Computer Science, Theory & Methods SC Computer Science GA 185DD UT WOS:000079652100005 ER PT J AU Donato, JM Schryver, JC Hinkel, GC Schmoyer, RL Leuze, MR Grandy, NW AF Donato, JM Schryver, JC Hinkel, GC Schmoyer, RL Leuze, MR Grandy, NW TI Mining multi-dimensional data for decision support SO FUTURE GENERATION COMPUTER SYSTEMS LA English DT Article DE data mining; personal bankruptcy; decision trees; partially recurrent neural networks ID NETWORKS AB Personal bankruptcy is an increasingly common yet little understood phenomenon. Attempts to predict bankruptcy have involved the application of data mining techniques to credit card data. This is a difficult problem, since credit card data is multi-dimensional, consisting of monthly account records and daily transaction records. In this paper, we describe a two-stage approach that combines decision trees and neural networks to predict personal bankruptcy using credit card data. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Joint Inst Computat Sci, Knoxville, TN 37996 USA. RP Leuze, MR (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 7 TC 11 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD APR PY 1999 VL 15 IS 3 BP 433 EP 441 DI 10.1016/S0167-739X(98)00086-7 PG 9 WC Computer Science, Theory & Methods SC Computer Science GA 185DD UT WOS:000079652100013 ER PT J AU Tonn, BE AF Tonn, BE TI Transcending oblivion SO FUTURES LA English DT Article AB This essay argues that a primary guiding vision for earth-life should be to emigrate from earth and this solar system prior to its oblivion by a dying Sun. While there is no urgency to accomplish this daunting task, there is cause for worry that today's behaviors may preclude earth-life from ever achieving this goal or, at the very least, delay achievement of the goal by many millions of years. Transcending oblivion is consistent with fundamental genetic imperatives for survival and psychological archetypes, myths, and motivations. Adopting this goal as an orientation for earth-life also overcomes several ethical problems associated with future generations and is consistent with environmental protection and sustainable development efforts. Transcending oblivion is not consistent, however, with other global trends towards ever increasing consumerism and individualism. It is suggested that new indicators be developed that measure progress towards transcending oblivion and risks to achieving the goal. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Tonn, BE (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 4500N,MS-6207, Oak Ridge, TN 37831 USA. EM bet@ornl.gov NR 5 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0016-3287 J9 FUTURES JI Futures PD APR-MAY PY 1999 VL 31 IS 3-4 BP 351 EP 359 PG 9 WC Economics; Planning & Development SC Business & Economics; Public Administration GA 180ED UT WOS:000079371900006 ER PT J AU Pal, A Indireshkumar, K Schwizer, W Hebbard, GS Faas, H Dent, J Chen, SY Kunz, P Fried, M Boesiger, P Brasseur, JG AF Pal, A Indireshkumar, K Schwizer, W Hebbard, GS Faas, H Dent, J Chen, SY Kunz, P Fried, M Boesiger, P Brasseur, JG TI Pressure-geometry relationships in the stomach analyzed through computer stimulation SO GASTROENTEROLOGY LA English DT Meeting Abstract C1 Penn State Univ, University Pk, PA 16802 USA. Univ Zurich Hosp, CH-8091 Zurich, Switzerland. ETH Zurich, Zurich, Switzerland. Royal Adelaide Hosp, Adelaide, SA 5000, Australia. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU W B SAUNDERS CO-ELSEVIER INC PI PHILADELPHIA PA 1600 JOHN F KENNEDY BOULEVARD, STE 1800, PHILADELPHIA, PA 19103-2899 USA SN 0016-5085 J9 GASTROENTEROLOGY JI Gastroenterology PD APR PY 1999 VL 116 IS 4 MA G4594 BP A1057 EP A1057 PN 2 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA 187GJ UT WOS:000079778404595 ER PT J AU Joussaume, S Taylor, KE Braconnot, P Mitchell, JFB Kutzbach, JE Harrison, SP Prentice, IC Broccoli, AJ Abe-Ouchi, A Bartlein, PJ Bonfils, C Dong, B Guiot, J Herterich, K Hewitt, CD Jolly, D Kim, JW Kislov, A Kitoh, A Loutre, MF Masson, V McAvaney, B McFarlane, N de Noblet, N Peltier, WR Peterschmitt, JY Pollard, D Rind, D Royer, JF Schlesinger, ME Syktus, J Thompson, S Valdes, P Vettoretti, G Webb, RS Wyputta, U AF Joussaume, S Taylor, KE Braconnot, P Mitchell, JFB Kutzbach, JE Harrison, SP Prentice, IC Broccoli, AJ Abe-Ouchi, A Bartlein, PJ Bonfils, C Dong, B Guiot, J Herterich, K Hewitt, CD Jolly, D Kim, JW Kislov, A Kitoh, A Loutre, MF Masson, V McAvaney, B McFarlane, N de Noblet, N Peltier, WR Peterschmitt, JY Pollard, D Rind, D Royer, JF Schlesinger, ME Syktus, J Thompson, S Valdes, P Vettoretti, G Webb, RS Wyputta, U TI Monsoon changes for 6000 years ago: Results of 18 simulations from the Paleoclimate Modeling Intercomparison Project (PMIP) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LAKE STATUS DATA; NORTHERN AFRICA; MIDDLE HOLOCENE; CLIMATE; BP; VARIABILITY; FEEDBACKS; CIRCULATION; MIDHOLOCENE; SENSITIVITY AB Amplification of the northern hemisphere seasonal cycle of insolation during the mid-Holocene causes a northward shift of the main regions of monsoon precipitation over Africa and India in all 18 simulations conducted for the Paleoclimate Modeling Intercomparison Project (PMIP). Differences among simulations are related to differences in model formulation. Despite qualitative agreement with paleoecological estimates of biome shifts, the magnitude of the monsoon increases over northern Africa are underestimated by all the models. C1 CEA Saclay, CNRS, UMR 1572, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. Hadley Ctr, Bracknell, Berks, England. Univ Wisconsin, Ctr Climat Res, Madison, WI 53706 USA. Univ Lund, S-22100 Lund, Sweden. Max Planck Inst Biogeochem, Jena, Germany. Univ Lund, Sch Ecol, Lund, Sweden. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. Univ Oregon, Dept Geog, Eugene, OR 97403 USA. Univ Reading, Dept Meteorol, Reading, Berks, England. Fac Sci St Jerome, CNRS, IMEP, Marseille, France. Univ Bremen, Bremen, Germany. Yonsei Univ, Seoul 120749, South Korea. Univ Moscow, Dept Meteorol & Climatol, Moscow, Russia. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Catholic Univ Louvain, Inst Astron & Geophys, B-3000 Louvain, Belgium. Res Ctr, Bur Meteorol, Melbourne, Vic, Australia. Univ Toronto, Dept Atmospher Sci, Toronto, ON, Canada. Penn State Univ, Ctr Earth Syst Sci, University Pk, PA 16802 USA. Ctr Natl Rech Meteorol, Toulouse, France. Univ Illinois, Dept Atmospher Sci, Chicago, IL 60680 USA. CSIRO, Div Atmospher Res, Canberra, ACT, Australia. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Geophys Data Ctr, Boulder, CO USA. RP Joussaume, S (reprint author), CEA Saclay, CNRS, UMR 1572, Lab Sci Climat & Environm, Bat 709, F-91191 Gif Sur Yvette, France. EM joussaume@cea.fr; taylor13@llnl.gov RI Bartlein, Patrick/E-4643-2011; Bonfils, Celine/H-2356-2012; Syktus, Jozef/E-7173-2011; Taylor, Karl/F-7290-2011; Peltier, William/A-1102-2008; Masson-Delmotte, Valerie/G-1995-2011; Valdes, Paul/C-4129-2013; Abe-Ouchi, Ayako/M-6359-2013; Broccoli, Anthony/D-9186-2014; Guiot, Joel/G-7818-2011; de NOBLET, Nathalie/O-8613-2015 OI Harrison, Sandy/0000-0001-5687-1903; Dong, Buwen/0000-0003-0809-7911; Loutre, Marie-France/0000-0001-6944-4038; Bartlein, Patrick/0000-0001-7657-5685; Bonfils, Celine/0000-0002-4674-5708; Syktus, Jozef/0000-0003-1782-3073; Taylor, Karl/0000-0002-6491-2135; Masson-Delmotte, Valerie/0000-0001-8296-381X; Abe-Ouchi, Ayako/0000-0003-1745-5952; Broccoli, Anthony/0000-0003-2619-1434; Guiot, Joel/0000-0001-7345-4466; NR 29 TC 250 Z9 273 U1 5 U2 35 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 APR 1 PY 1999 VL 26 IS 7 BP 859 EP 862 DI 10.1029/1999GL900126 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 182AW UT WOS:000079477200013 ER PT J AU Lloyd, RD Fisher, DR Schlenker, RA Miller, SC AF Lloyd, RD Fisher, DR Schlenker, RA Miller, SC TI Some problems in the skeletal dosimetry of bone-seeking radionuclides SO HEALTH PHYSICS LA English DT Article DE cancer; Pu-239; Sr-90; skeleton ID RELATIVE DISTRIBUTION FACTORS; CELLS; PU-239; CARCINOGENESIS; EMITTERS; BEAGLES; RA-226; RISK AB There are fundamental problems with the calculation of radiation doses to the skeleton from internal emitters deposited in bone. Some of these include dose inhomogeneities, identity of cells at risk and their dynamics, changing deposition patterns of bone-seeking radionuclides with time after exposure, seemingly unique responses of the skeleton to each deposited radionuclide, the role of radioactive progeny produced by deposited emitters and their individual dynamics and effects, different responses of mammals of different ages at exposure to identical dosages, different responses to different chemical forms of a given radionuclide, and different responses to an identical dose from a given radionuclide at different dose-rates. This situation makes it necessary to choose some common dose parameter that will allow the overall effects of different radionuclides to be compared directly so that projected effects of each of them in humans can be estimated. For radiation protection purposes, it appears premature to abandon the concept of average skeletal dose (which appears to be a practical compromise for use) until an undelusive. non-artificial and uncontrived method of calculating absorbed dose to the appropriate cells in hone is developed that fulfills the requirement of equal cancer response for equal skeletal dose for all circumstances. C1 Univ Utah, Dept Radiol, Div Radiobiol, Salt Lake City, UT 84112 USA. Pacific NW Lab, Richland, WA 99352 USA. Madison Res Grp Inc, Willowbrook, IL 60521 USA. FU NCI NIH HHS [R01-CA66759] NR 47 TC 6 Z9 6 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD APR PY 1999 VL 76 IS 4 BP 402 EP 412 DI 10.1097/00004032-199904000-00009 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 175RM UT WOS:000079108800009 PM 10086602 ER PT J AU Suter, GW AF Suter, GW TI Developing conceptual models for complex ecological risk assessments SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE problem formulation; multi-stressor; causality AB Conceptual models are representations of the assumed relationship between sources and effects. They serve three important purposes. (1) Their creation compels assessors to think through and clarify their assumptions concerning the activities being assessed. (2) They serve as a communication tool for conveying those assumptions to risk managers and stakeholders. (3) They provide a basis for organizing and conducting the risk assessment. Conceptual models for risk assessments off chemical contaminants have not been problematical because they simply portray the flow of the contaminant from a source to a receptor that experiences toxic effects. However, ecological risk assessments must increasingly deal with direct and indirect effects on multiple endpoint receptors and with multiple complex activities including both physical effects and toxic effects. This complexity may result in conceptual models that are incomplete, ambiguous, or simply too complex to be understood. This paper presents a strategy for creating conceptual models for complex ecological risk assessments that are not only complete but also clear and comprehensible. The strategy also promotes efficiency by creating modular component models for activities, sites, and receptors that can be reused in different combinations in different assessments. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Suter, GW (reprint author), US EPA, Natl Ctr Environm Assessment, MS-117,26 W Martin Luthr King Dr, Cincinnati, OH 45268 USA. NR 9 TC 25 Z9 27 U1 0 U2 9 PU CRC PRESS INC PI BOCA RATON PA 2000 CORPORATE BLVD NW, JOURNALS CUSTOMER SERVICE, BOCA RATON, FL 33431 USA SN 1080-7039 J9 HUM ECOL RISK ASSESS JI Hum. Ecol. Risk Assess. PD APR PY 1999 VL 5 IS 2 BP 375 EP 396 PG 22 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 194WE UT WOS:000080217100014 ER PT J AU Suter, GW AF Suter, GW TI A framework for assessment of ecological risks from multiple activities SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE programmatic assessment; framework; integrated assessment; multistressor ID LIFE AB The standard framework for ecological risk assessment does not explicitly address multiple activities. Although this has not prevented its use for assessments of risks from multiple agents, the routine assessment of complex programs or of multiple agents acting on a site, watershed or region would be aided by use of a framework that is designed for that purpose. The framework proposed in this paper is modular with respect to the individual activities which makes the assessment more manageable and more efficient when the same activities are addressed in multiple programs or at multiple sites. It explicitly allows for analysis of indirect effects in terms of causal chains. It includes links to other risk assessments for which changes in ecological conditions are the hazardous agent. For example, changes in ecological condition may create risks to agricultural economies or to the cultural resource values of a site. Finally, the framework includes a standard approach to estimating the combined effects of the multiple agents acting on a receptor. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Suter, GW (reprint author), US EPA, Natl Ctr Environm Assessment, MS-117,26 W Martin Luther King Dr, Cincinnati, OH 45268 USA. NR 21 TC 18 Z9 20 U1 1 U2 3 PU CRC PRESS INC PI BOCA RATON PA 2000 CORPORATE BLVD NW, JOURNALS CUSTOMER SERVICE, BOCA RATON, FL 33431 USA SN 1080-7039 J9 HUM ECOL RISK ASSESS JI Hum. Ecol. Risk Assess. PD APR PY 1999 VL 5 IS 2 BP 397 EP 413 PG 17 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 194WE UT WOS:000080217100015 ER PT J AU Allan, ML Kavanaugh, SP AF Allan, ML Kavanaugh, SP TI Thermal conductivity of cementitious grouts and impact on heat exchanger length design for ground source heat pumps SO HVAC&R RESEARCH LA English DT Article AB Design length and performance of heat exchangers for ground source heat pumps strongly depend on the thermal conductivity of the backfill material. Laboratory studies were undertaken to determine means of improving thermal conductivity of cementitious backfill grouts. The influence of fillers and admixtures was examined Significant improvement of grout thermal conductivity, was readily achieved through appropriate materials selection and mix design. Fillers such as silica sand, alumina grit, steel grit, and silicon carbide increased the thermal conductivity, to values ranging from 1.7 to 3.3 W/(m K) (0.98 to 1.9 Btu/h ft degrees F). Near cement grouts had conductivities of 0.80 to 0.87 W/(m K) (0.46 to 0.50 Btu/h ft degrees F). Filled cementitious grouts had better retention of thermal conductivity under drying conditions than bentonites and neat cements. The reduction in required bare length possible with cement-sand grouts was predicted theoretically for an example heat pump system and found to be 22 to 37%, depending on soil conductivity and bore diameter. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Alabama, Dept Mech Engn, Tuscaloosa, AL USA. RP Allan, ML (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Berndt, Marita/D-1901-2014 OI Berndt, Marita/0000-0002-6622-0597 NR 16 TC 10 Z9 12 U1 0 U2 9 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 1078-9669 J9 HVAC&R RES JI HVAC&R Res. PD APR PY 1999 VL 5 IS 2 BP 87 EP 98 PG 12 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 190JU UT WOS:000079960100002 ER PT J AU Kennel, SJ AF Kennel, SJ TI 523-14A anti-rat CD 63 SO HYBRIDOMA LA English DT Article C1 Oak Ridge Natl Lab, Lockheed Martin Energy Res Corp, Oak Ridge, TN 37831 USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Lockheed Martin Energy Res Corp, POB 2008,4500-S,MS 6101, Oak Ridge, TN 37831 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 0272-457X J9 HYBRIDOMA JI Hybridoma PD APR PY 1999 VL 18 IS 2 BP 215 EP 215 PG 1 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Immunology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology GA 202CU UT WOS:000080635200016 ER PT J AU Newman, WI Symbalisty, EMD Ahrens, TJ Jones, EM AF Newman, WI Symbalisty, EMD Ahrens, TJ Jones, EM TI Impact erosion of planetary atmospheres: Some surprising results SO ICARUS LA English DT Article ID CRETACEOUS-TERTIARY BOUNDARY; COMET SHOEMAKER-LEVY-9; JUPITER; EXPLOSION; EXTINCTION; FEATURES; ORIGIN; CRATER; EJECTA; VENUS AB We have investigated by analytical and computational means the effect of Cretaceous-Tertiary (K/T) size impacts (5 x 10(30) erg, 9-km-radius bolide of 10(19) g) on terrestrial atmospheres. We have extended analytically the approximate solution due to A. S, Kompaneets (1960, Sov. Phys, Dokl, Engl. Transl, 5, 46-48) for the blast wave obtained for atmospheric nuclear explosions (idealized to isothermal atmospheres) to ideal adiabatic atmospheres and to data-based models of the Earth's atmosphere. For the first time, we have been able to obtain analytically the particle trajectories in an isothermal atmosphere. The outcome of this nonlinear analysis is that a massive impact (without the subsequent ejection of substantial mass) would only influence a column of approximate to 30-km radius in the Earth's atmosphere and that the shocked gas would be propelled up and against the column "wall," but would not escape from the planet. We examined the validity of "hemispheric blowoff," the hypothesis that all material in a hemisphere lying above a plane tangent to the point of impact radially accelerated outward and, if sufficiently energetic, would also be ejected. We adapted and used a state-of-the-art code (CAVEAT), a hybrid Los Alamos-Sandia Lagrangian-Eulerian finite difference scheme for multimaterial flow problems with large distortion and internal slip. In our CAVEAT calculations, the vapor cloud produced by the impact produces a shock that is orders of magnitude stronger than any previous use of such codes. We developed new methods to test the accuracy and convergence of CAVEAT for KIT size impact events, and it proved to be a robust tool. We explored a KIT size impact where the 9-km-radius bolide was vaporized and injected into the atmosphere and found no radial outflow in agreement with the analytic model but, instead, a 50-km-radius vertical column formed with only a small fraction of material reaching escape velocity-no more than about 7% of the vaporized bolide plus atmospheric mass will escape the gravitation of the Earth. (C) 1999 Academic Press. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. CALTECH, Inst Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Newman, WI (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. RI Newman, William/E-5918-2011 OI Newman, William/0000-0002-9835-1428 NR 61 TC 33 Z9 33 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 1999 VL 138 IS 2 BP 224 EP 240 DI 10.1006/icar.1999.6076 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 189MG UT WOS:000079908400006 ER PT J AU Akyildiz, IF Levine, DA Joe, I AF Akyildiz, IF Levine, DA Joe, I TI A slotted CDMA protocol with BER scheduling for wireless multimedia networks SO IEEE-ACM TRANSACTIONS ON NETWORKING LA English DT Article DE BER scheduling; code division multiple access; multimedia traffic; power control; priority; wireless networks ID RESERVATION MULTIPLE ACCESS; POWER-CONTROL; ATM NETWORKS; CAPACITY; SYSTEMS; SERVICE; VOICE AB In future wireless multimedia networks, there will he a mixture of different traffic classes which have their own maximum tolerable bit error rate (BER) requirements. In this paper, a novel medium access control (MAC) protocol called wireless multimedia access control protocol with BER scheduling tin short form, WISPER) for CDMA-based systems is proposed. WISPER utilizes the novel idea of scheduling the transmission of multimedia packets according to their BER requirements. The scheduler assigns priorities to the packets, and performs an iterative procedure to determine a good accommodation of the highest-priority packets in the slots of a frame so that packets with equal or similar BER requirements are transmitted in the same slots. The proposed WISPER protocol has been validated using a software emulator on the cellular environment. Performance evaluation results based on the implementation are also included in the paper. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. BellSouth, Atlanta, GA 30385 USA. Oak Ridge Natl Lab, Network Res Grp, Oak Ridge, TN 37831 USA. RP Akyildiz, IF (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. RI Akyildiz, Ian/G-7136-2011 OI Akyildiz, Ian/0000-0002-8099-3529 NR 30 TC 120 Z9 123 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1063-6692 J9 IEEE ACM T NETWORK JI IEEE-ACM Trans. Netw. PD APR PY 1999 VL 7 IS 2 BP 146 EP 158 DI 10.1109/90.769764 PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 200GR UT WOS:000080531700001 ER PT J AU Hicks, MJ Snell, MS Sandoval, JS Potter, CS AF Hicks, MJ Snell, MS Sandoval, JS Potter, CS TI Physical protection systems - Cost and performance analysis: A case study SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB Design and analysis of physical protection systems requires: 1) identification of mission critical assets; 2) identification of potential threats that might undermine mission capability; 3) identification of the consequences of loss of mission-critical assets (e.g., time and cost to recover required capability and impact on operational readiness); and 4) analysis of the effectiveness of physical protection elements. CPA - Cost and Performance Analysis - addresses the fourth of these four issues. CPA is a methodology that joins Activity Based Cost estimation with performance-based analysis of physical protection systems. CPA offers system managers an approach that supports both tactical decision making and strategic planning. Current exploratory applications of the CPA methodology address analysis of alternative conceptual designs. Hypothetical data is used to illustrate this process. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Hicks, MJ (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 6 TC 8 Z9 8 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD APR PY 1999 VL 14 IS 4 BP 9 EP 13 DI 10.1109/62.756078 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 184FR UT WOS:000079600400006 ER PT J AU Chisholm, GH Eckmann, ST Lain, CM Veroff, RL AF Chisholm, GH Eckmann, ST Lain, CM Veroff, RL TI Understanding integrated circuits SO IEEE DESIGN & TEST OF COMPUTERS LA English DT Article AB Reverse engineering is the process of learning as much as possible about an IC device by transforming a detailed design description into successively higher levels of abstraction. This tutorial focuses on deriving a module-level description from a gate-level netlist. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ New Mexico, Albuquerque, NM 87131 USA. RP Chisholm, GH (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 1 Z9 2 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0740-7475 J9 IEEE DES TEST COMPUT JI IEEE Des. Test Comput. PD APR-JUN PY 1999 VL 16 IS 2 BP 26 EP 37 DI 10.1109/54.765201 PG 12 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 195DH UT WOS:000080233500006 ER PT J AU Siders, CW Siders, JLW Omenetto, FG Taylor, AJ AF Siders, CW Siders, JLW Omenetto, FG Taylor, AJ TI Multipulse interferometric frequency-resolved optical gating SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE FROG; ionization; plasma; ultrafast pulses ID ULTRASHORT LASER-PULSES; DOMAIN INTERFEROMETER; LONGITUDINAL INTERFEROMETRY; HARMONIC-GENERATION; SINGLE SPECTROGRAM; PHASE; IONIZATION; INTENSITY; DYNAMICS; PLASMA AB We review multipulse interferometric frequency-resolved optical gating (MI-FROG) as a technique, uniquely suited for pump-probe coherent spectroscopy using amplified visible and near-infrared short-pulse systems and/or emissive targets, for time-resolving ultrafast phase shifts and intensity changes. Application of polarization-gate MI-FROG to the study of ultrafast ionization in gases is presented. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Siders, CW (reprint author), Univ Calif San Diego, La Jolla, CA 92093 USA. NR 32 TC 6 Z9 7 U1 2 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1999 VL 35 IS 4 BP 432 EP 440 DI 10.1109/3.753648 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 181CV UT WOS:000079423800005 ER PT J AU Tignon, J Marquezini, MV Hasche, T Chemla, DS AF Tignon, J Marquezini, MV Hasche, T Chemla, DS TI Spectral interferometry of semiconductor nanostructures SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE excitons; gallium alloys; magnetic field effects; optical interferometry; phase measurement; semiconductor materials ID GAAS QUANTUM-WELLS; REFRACTIVE-INDEX; ULTRAFAST PHASE; FANO RESONANCES; EXCITONS; DISPERSION; MICROCAVITIES; DYNAMICS; MAGNETOEXCITON; INTERFERENCE AB Fourier transform spectral interferometry is applied to measure both amplitude and phase of the electric field in different types of semiconductor nanostructures, thus determining the real and imaginary parts of the dielectric function, The importance of measuring the phase is shown and discussed in three studies. First, the phase measurement is used to access directly the refractive index across excitonic resonances in bulk GaAs and AlGaAs-GaAs quantum wells, with unprecedented resolution. Second, we measure the density dependence of the full dielectric function across a Fano resonance in bulk GaAs and show that this allows us to obtain some information on the collisional broadening of the usually hidden linewidth of the coupled esciton/continuum. Third, the phase is studied in a complex heterostructure, a semiconductor microcavity. We investigate and discuss the effect of the cavity detuning and of the excitation density. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Tignon, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 60 TC 22 Z9 22 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1999 VL 35 IS 4 BP 510 EP 522 DI 10.1109/3.753655 PG 13 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 181CV UT WOS:000079423800012 ER PT J AU Bayramian, AJ Marshall, CD Schaffers, KI Payne, SA AF Bayramian, AJ Marshall, CD Schaffers, KI Payne, SA TI Characterization of Yb3+: Sr5-xBax(PO4)(3)F crystals for diode-pumped lasers SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE crystal growth; emission; gain measurement; lasers; rare-earth compounds; solid lasers; spectroscopy; ytterbium ID YB-YAG LASER; STRONTIUM FLUOROVANADATE; MU-M; SPECTROSCOPIC PROPERTIES; PERFORMANCE; GROWTH; SR-5(PO4)(3)F; FLUORAPATITE; ABSORPTION; GLASSES AB Ytterbium-doped Sr-5(PO4)(3)F (S-FAP) has been shown to be a useful material for diode pumping, since it displays high gain, low loss, and a long radiative lifetime. One of the issues with S-FAP is that it has a relatively narrow absorption bandwidth (similar to 5 nm) at 900 nm, the diode-pumping wavelength, while the diode's output bandwidth can be large (similar to 10 nm), By changing the host slightly, the absorption feature can be broadened to better match the pump bandwidth. Four mixed crystal boules of Yb3+:Sr5-xBax(PO4)(3)F were grown by the Czochralski method with x = 0.25, 0.3, 1, and 2. The bandwidth of the 900-nm absorption feature was found to grow with increasing barium concentration from 4.7 nm to a maximum of 15.9 nm, Emission spectra showed a similar bandwidth increase with barium content from 4.9 nm to a maximum of 10 nm, Emission cross sections for these materials were deduced by the methods of reciprocity, the Einstein method, and small-signal gain. The absorption feature's homogeneity was probed using a tunable pump source which qualitatively showed that the barium-broadened lines mere at least partly inhomogeneous, Each of these materials lased with a variety of output couplers. This family of materials was found to provide suitable laser hosts where a broader absorption and/or emission bandwidth is desired. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Bayramian, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 34 TC 20 Z9 21 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1999 VL 35 IS 4 BP 665 EP 674 DI 10.1109/3.753672 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 181CV UT WOS:000079423800029 ER PT J AU Zory, JSOPS Schwartz, BD Setzko, RS Emanuel, MA Sperry, VR AF Zory, JSOPS Schwartz, BD Setzko, RS Emanuel, MA Sperry, VR TI Antiguided array diode lasers fabricated with modulated cap thin p-clad structure SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE antiguided array; InGaAs-GaAs-AlGaAs; pulsed anodization; thin p-clad ID PHASE-LOCKED ARRAYS; QUANTUM-WELL LASERS; HIGH-POWER; OPERATION AB Antiguided array lasers were fabricated in thin p-clad, InGaAs-GaAs single quantum-well material. The required lateral refractive index variation was achieved by precisely modulating the thickness of the GaAs cap layer using a novel pulsed anodization/etching technique. Edge-emitting arrays having 20 lasers on 7-mu m centers with 5-mu m-wide gain regions were characterized, At 1.2 times the pulsed current threshold (I-th). the central lobe of the lateral far field of the arrays contained about 75% of the beam power and was about twice the diffraction limit (FWHM = 0.8 degrees). At 10 x I-th, the central lobe contained about 60% of the beam power and was about 1.6 degrees wide. C1 Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. Raytheon Opt Syst, Danbury, CT 06810 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Zory, JSOPS (reprint author), Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. NR 16 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD APR PY 1999 VL 11 IS 4 BP 415 EP 417 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 179JE UT WOS:000079322500007 ER PT J AU Prigl, R Brown, HN Bunce, G Carey, RM Cushman, P Danby, GT Debevec, PT Deng, H Deninger, W Dhawan, SK Druzhinin, VP Duong, L Earle, W Efstathiadis, E Farley, FJM Fedotovich, GV Giron, S Gray, F Perdekamp, MG Grossmann, A Haeberlen, U Hare, M Hazen, ES Hertzog, DW Hughes, VW Iwasaki, M Jungmann, K Kawall, D Kawamura, M Khazin, BI Kindem, J Krienen, F Kronkvist, I Larsen, R Lee, YY Liu, W Logashenko, I McNabb, R Meng, W Mi, JL Miller, D Miller, JP Morse, WM Neumayer, P Onderwater, CJG Orlov, Y Pai, C Polly, C Pretz, J Putlitz, GZ Redin, SI Rind, O Roberts, BL Ryskulov, N Sanders, R Sedykh, S Semertzidis, YK Serednyakov, S Shatunov, YM Solodov, E Sossong, M Steinmetz, A Sulak, LR Tanaka, M Timmermans, C Trofimov, A Urner, D Warburton, D Winn, D Yamamoto, A Zimmerman, D AF Prigl, R Brown, HN Bunce, G Carey, RM Cushman, P Danby, GT Debevec, PT Deng, H Deninger, W Dhawan, SK Druzhinin, VP Duong, L Earle, W Efstathiadis, E Farley, FJM Fedotovich, GV Giron, S Gray, F Perdekamp, MG Grossmann, A Haeberlen, U Hare, M Hazen, ES Hertzog, DW Hughes, VW Iwasaki, M Jungmann, K Kawall, D Kawamura, M Khazin, BI Kindem, J Krienen, F Kronkvist, I Larsen, R Lee, YY Liu, W Logashenko, I McNabb, R Meng, W Mi, JL Miller, D Miller, JP Morse, WM Neumayer, P Onderwater, CJG Orlov, Y Pai, C Polly, C Pretz, J Putlitz, GZ Redin, SI Rind, O Roberts, BL Ryskulov, N Sanders, R Sedykh, S Semertzidis, YK Serednyakov, S Shatunov, YM Solodov, E Sossong, M Steinmetz, A Sulak, LR Tanaka, M Timmermans, C Trofimov, A Urner, D Warburton, D Winn, D Yamamoto, A Zimmerman, D TI Status of the BNL muon (g-2) experiment SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE g factor; muon storage ring; nuclear magnetic resonance; spin precession; standard model; superconducting coils; supersymmetry ID DIPOLE-MOMENT; CONSTRAINTS; NMR AB The muon (g-2) experiment at Brookhaven completed a first run in June and July 1997. The main components of the experiment, which include the superconducting inflector, the superferric storage ring, the electrostatic quadrupoles and the lead scintillating fiber electron calorimeters, have been commissioned satisfactorily. Our first measurement of the ratio R of the spin precession frequency of the positive muon relative to that of a free proton, R = (3.707 219+/-0.000 048 x 10(-3), is in good agreement with the previous CERN measurements for mu(+) and mu(-), and has approximately the same uncertainty as each of these measurements. Ln spring 1998 a muon kicker was installed and successfully tested in the storage ring magnet and a significant improvement in the knowledge of the muon g-factor Is expected from upcoming runs in August 1998 and January 1999. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Cornell Univ, Newman Lab, Ithaca, NY 14853 USA. Fairfield Univ, Fairfield, CT 06430 USA. Univ Heidelberg, Inst Phys, D-69120 Heidelberg, Germany. Max Planck Inst Med Forsch, D-69120 Heidelberg, Germany. Univ Illinois, Dept Phys, Champaign, IL 61820 USA. Univ Minnesota, Dept Phys, Minneapolis, MN 55455 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. KEK, Tsukuba, Ibaraki, Japan. Tokyo Inst Technol, Tokyo 152, Japan. Yale Univ, Dept Phys, New Haven, CT 06511 USA. RP Prigl, R (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Jungmann, Klaus/A-7142-2010; jungmann, klaus/H-1581-2013; Semertzidis, Yannis K./N-1002-2013; Logashenko, Ivan/A-3872-2014; Iwasaki, Masahiko/M-8433-2014 OI jungmann, klaus/0000-0003-0571-4072; Iwasaki, Masahiko/0000-0002-3460-9469 NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 182 EP 185 DI 10.1109/19.769558 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600010 ER PT J AU Kupferman, SL Hamilton, CA AF Kupferman, SL Hamilton, CA TI Deployment of a compact, transportable, fully automated Josephson voltage standard SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE DC; Josephson; standard; transportable; voltage AB A compact, transportable, Josephson voltage standard, first reported at CPEM96, has now been field tested and has had ten months of use as a primary standard by National Aeronautics and Space Administration (NASA) laboratories. We discuss here its uncertainty assessment, the results of intercomparisons with conventional Josephson standards, operator training, and the experience of users. A second similar standard with an improved microwave system has been fabricated at the National Institute of Standards and Technology (NIST) and delivered to Sandia National Laboratories (SNL) for use by Department of Energy (DOE) standards laboratories. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Kupferman, SL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 9 TC 9 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 249 EP 252 DI 10.1109/19.769575 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600027 ER PT J AU Singh, A Rajapatirana, S Men, Y Granatstein, VL Ives, RL Antolak, AJ AF Singh, A Rajapatirana, S Men, Y Granatstein, VL Ives, RL Antolak, AJ TI Design of a multistage depressed collector system for 1-MW CW gyrotrons - Part I: Trajectory control of primary and secondary electrons in a two-stage depressed collector SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on CRMs and Gyrotrons CY MAY 18-21, 1998 CL MA ALE HACHAMISHA, ISRAEL SP Israeli Acad Sci & Humanities DE charged particle trajectory control; depressed collectors; gyrotrons; high-power millimeter-wave sources; secondary emission; tracing of backscattered electron trajectories ID MAGNETIC-FIELD PROFILES; ORBIT GYROTRONS; EFFICIENCY; POWER; BEAM AB Part I of this paper presents the design of a two-stage depressed collector for a 110-GNz, 1-MW gyrotron, taking into, account the trajectories of electrons backscattered from the electrode surfaces. The collector geometry and the magnetic circuit were adjusted in order to minimize the effect of backscattered electrons, A computer code was employed which is based on a new algorithm designed to give good representation to a variety of energy levels and angles of emergence of backscattered electrons, The collector efficiency estimated on the basis of primary electrons alone was 68%. The estimated collector efficiency which included also the effect of backscattered electrons was 60%. In the latter case the surface of the collectors was assumed to be that of polished copper. The techniques and codes used in the design are reviewed and results of trajectory tracing are presented for primaries and secondaries. Part IT of the paper presents the system aspects, including the mechanical and thermal designs and the soIid-state power supply design. These take into account the considerations of safety, reliability, and the user interface. C1 Univ Maryland, Inst Plasma Res, College Pk, MD 20770 USA. Calabazas Creek Res, Saratoga, CA 95070 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Singh, A (reprint author), Univ Maryland, Inst Plasma Res, College Pk, MD 20770 USA. NR 31 TC 30 Z9 30 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1999 VL 27 IS 2 BP 490 EP 502 DI 10.1109/27.772278 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 211YM UT WOS:000081189500025 ER PT J AU Keidar, M Beilis, II Anders, A Brown, IG AF Keidar, M Beilis, II Anders, A Brown, IG TI Free-boundary vacuum arc plasma jet expansion in a curved magnetic field SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE curved magnetic field; macroparticle filter; plasma jet ID TRANSPORT; FILTERS; DUCTS AB A hydrodynamic model of free-boundary vacuum are plasma jet flow through a curved magnetic field has been developed. The plasma flow was modeled by sourceless steady-state equations, and the free boundary of the plasma was determined as a part of the solution of the gas-dynamic equations, It was found that the maximum plasma density shifts with respect to the centerline. The shift is maximum at the 90 degrees guide exit plane and for the case of low magnetic field. The maximum increase in longitudinal plasma velocity along the duct was shown to be a factor of three, The plasma distribution within the duct was analyzed experimentally using a deposition probe technique. The plasma jet expansion predicted by the model was compared with the experiment and a good qualitative agreement was found. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tel Aviv Univ, Elect Discharge & Plasma Lab, IL-69978 Tel Aviv, Israel. RP Cornell Univ, Dept Mech & Aerosp Engn, Ithaca, NY 14853 USA. EM keidar@mae.cornell.edu NR 22 TC 10 Z9 10 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 EI 1939-9375 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1999 VL 27 IS 2 BP 613 EP 619 DI 10.1109/27.772293 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 211YM UT WOS:000081189500040 ER PT J AU Brubaker, MA Nelson, JK AF Brubaker, MA Nelson, JK TI Development and calibration of a network-based streaming electrification model for core-form transformer structures SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE transformers; static electrification; oil flow; winding ducts; charge density; streaming current; static potential AB Streaming electrification occurs in large power transformers when oil circulated for cooling purposes acts to separate charges from the Debye layer on the cellulose insulation surfaces. This phenomenon is believed to have caused several catastrophic transformer failures and remains to be satisfactorily understood in realistic geometries. A network-based streaming electrification model is presented which utilizes single winding ducts as the basic element to investigate a core-form structure. The network is first analyzed using hydraulic duct parameters to calculate the oil flow distributions within the structure. This data is then provided to the electrification solver which predicts the charge densities at each duct outlet. The charge density results are ultimately used to determine the streaming potentials at each node based on an a suitable matrix of leakage resistances. Development of the network model is presented along with empirically-based calibration data for a realistic section of core-form transformer geometry. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Rensselaer Polytech Inst, Troy, NY 12180 USA. RP Brubaker, MA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 6 Z9 7 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD APR PY 1999 VL 14 IS 2 BP 431 EP 436 DI 10.1109/61.754085 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 180CN UT WOS:000079367700019 ER PT J AU Fuchs, EF You, Y Roesler, DJ AF Fuchs, EF You, Y Roesler, DJ TI Modeling and simulation, and their validation of three-phase transformers with three legs under DC bias SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE three-phase transformer model; nonlinear; DC bias; influence of tank; magnetic history; residual magnetism; combination of time and frequency domains AB This paper proposes a new model for three-phase transformers with three legs with and without task under DC bias based on electric and magnetic circuit theory. For the calculation of the nonsinusoidal no-load currents, a combination of time and frequency domains is used. The analysis shows that 1) asymmetric three-phase transformers with three legs generate magnetising currents with triplen harmonics not being of the aero-sequence type. 2) The wave shapes of the three magnetising currents of (asymmetric) transformers are dependent on the phase sequence. 3) The magnetic history of transformer magnetization - due to residual magnetization and hysteresis of the tank - cannot be ignored if a DC bias is present and the magnetic influence of the tank is relatively strong, e.g., for oil-cooled trans; formers. 4) Symmetric three-phase transformers with three legs generate no-load currents without triplen harmonics. 5) The effects of DC bias currents (e.g., reactive power demand, harmonic distortion) can be suppressed employing symmetric three-phase transformers with three legs including task. Measurements corroborate computational results; thus this nonlinear model is valid and accurate. C1 Univ Colorado, Boulder, CO 80309 USA. US DOE, Washington, DC 20585 USA. RP Fuchs, EF (reprint author), Univ Colorado, Boulder, CO 80309 USA. NR 7 TC 39 Z9 47 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD APR PY 1999 VL 14 IS 2 BP 443 EP 449 DI 10.1109/61.754087 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 180CN UT WOS:000079367700021 ER PT J AU Husson, SM King, CJ AF Husson, SM King, CJ TI Carbon dioxide-sustained adsorption of lactic acid at pH > pK(a) of the acid SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID CARBOXYLIC-ACIDS; AMINE EXTRACTANTS; ORGANIC-SOLVENT; FERMENTATION; EQUILIBRIA; SORBENTS; WATER; BASE AB Experimental data are presented for batch and fixed-bed adsorption of lactic acid from aqueous sodium lactate solutions onto the tertiary amine sorbents, Dowex MWA-1 and Amberlite IRA-35, in the presence of carbon dioxide. The effects of carbon dioxide pressure and sodium lactate concentration on lactate uptake capacity were measured. A simple complexation model, which includes chemical-equilibria and mass- and charge-balance equations, was developed to describe the system. There are no fitted parameters in the model. The model predictions compare well with batch adsorption data. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP King, CJ (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. EM shusson@clemson.edu; jud.king@ucop.edu NR 32 TC 6 Z9 6 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1999 VL 38 IS 4 BP 1625 EP 1632 DI 10.1021/ie980428v PG 8 WC Engineering, Chemical SC Engineering GA 184JY UT WOS:000079609800050 ER PT J AU Bond, AH Chang, FWK Thakkar, AH Williamson, JM Gula, MJ Harvey, JT Griffin, ST Rogers, RD Horwitz, EP AF Bond, AH Chang, FWK Thakkar, AH Williamson, JM Gula, MJ Harvey, JT Griffin, ST Rogers, RD Horwitz, EP TI Design, synthesis, and uptake performance of ABEC resins for the removal of pertechnetate from alkaline radioactive wastes SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID ANION-EXCHANGE RESIN; AQUEOUS BIPHASIC SYSTEMS; HANFORD TANK WASTES; NITRIC-ACID; REPROCESSING SOLUTIONS; SORPTION BEHAVIOR; EXTRACTION; TECHNETIUM; TECHNOLOGIES; SOLVENT AB Removal of technetium-99 and iodine-129 from alkaline radioactive wastes remaining from weapons processing is necessary as these radionuclides are long-lived and environmentally mobile in their most stable chemical forms (TcO4- and I-). Technetium-99 and iodine-129 are ill-suited to thermal processing because of the volatility of their high-temperature species. Resins based on Aqueous Biphasic Extraction Chromatography, ABEC, selectively extract TcO4- and I- from alkaline radioactive wastes and offer the advantage that stripping is accomplished by eluting with water. To date, most studies of ABEC resins have been performed using materials designed for analytical separations that are not suitable for process-scale applications. The development of ABEC resins compatible with a large-scale chromatographic apparatus is reported. ABEC resins of 50-100 mesh size showing <10% swelling during crossover from a 4 M NaOH load to a water strip and volume distribution ratios for pertechnetate as high as 160 have been synthesized, and their properties are discussed. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Alabama, Dept Chem, Tuscaloosa, AL 35487 USA. Eichrom Ind Inc, Darien, IL 60561 USA. RP Bond, AH (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Rogers, Robin D./0000-0001-9843-7494 NR 32 TC 10 Z9 10 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1999 VL 38 IS 4 BP 1676 EP 1682 DI 10.1021/ie980072n PG 7 WC Engineering, Chemical SC Engineering GA 184JY UT WOS:000079609800054 ER PT J AU Bond, AH Gula, MJ Harvey, JT Duffey, JM Horwitz, EP Griffin, ST Rogers, RD Collins, JL AF Bond, AH Gula, MJ Harvey, JT Duffey, JM Horwitz, EP Griffin, ST Rogers, RD Collins, JL TI Flowsheet feasibility studies using ABEC resins for removal of pertechnetate from nuclear wastes SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID ANION-EXCHANGE RESIN; NITRIC-ACID; TRANSPLUTONIUM ELEMENTS; REPROCESSING SOLUTIONS; SORPTION BEHAVIOR; PHOSPHINE OXIDES; EXTRACTION; TECHNETIUM; TECHNOLOGIES; STRONTIUM AB A flowsheet for the extraction and immobilization of (TcO4-)-Tc-99 from radioactive wastes has been developed. The three-stage flowsheet comprises selective sorption of (TcO4-)-Tc-99 by ABEC resins, secondary concentration of (TcO4-)-Tc-99 from H2O by a nonselective silica-based anion-exchange resin, and encapsulation and immobilization of the radionuclide-loaded anion-exchange resin in hydrous titanium oxide microspheres. Each process has been independently tested, and the results are discussed. The utility of this flowsheet in the extraction and immobilization of (TcO4-)-Tc-99 from alkaline radioactive wastes, neutralized nuclear fuel reprocessing streams, alkaline vitrification off-gas scrubber solutions, and solvent wash stages from the treatment of acidic high-level wastes is also presented. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Eichrom Ind Inc, Darien, IL 60561 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Bond, AH (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Rogers, Robin D./0000-0001-9843-7494 NR 48 TC 8 Z9 8 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1999 VL 38 IS 4 BP 1683 EP 1689 DI 10.1021/ie980611o PG 7 WC Engineering, Chemical SC Engineering GA 184JY UT WOS:000079609800055 ER PT J AU Kuzay, TM Collins, JT Koons, J AF Kuzay, TM Collins, JT Koons, J TI Boiling liquid nitrogen heat transfer in channels with porous copper inserts SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID SYNCHROTRON SOURCES; MONOCHROMATORS; UNDULATORS; THIN AB Copper mesh. compressed and formed into porous matrices of various shapes and sizes, has been routinely used in high heat load/flux component cooling with water at the Advanced Photon Source (APS) to significantly enhance the heat transfer performance. Now the same mesh configuration is being applied to the cryogenic cooling of optical components, such as the monochromators, mirrors and multilayers with liquid nitrogen in single phase. Two-phase heat transfer is avoided to prevent flow-induced noise (vibrations and jitter) in the ultrasensitive optical components. Hence there is a great need to understand the limits of single-phase heat transfer with copper mesh using liquid nitrogen. Recently an extensive experimental program has been undertaken to investigate the heat transfer limits in conductive porous matrices with liquid nitrogen as the coolant. This paper presents the data obtained, compares the data with existing single- and two-phase correlations, and interprets the results for cryo-cooled optical component cooling applications. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Expt Fac Div, Argonne, IL 60439 USA. RP Kuzay, TM (reprint author), Argonne Natl Lab, Adv Photon Source, Expt Fac Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 11 Z9 11 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD APR PY 1999 VL 42 IS 7 BP 1189 EP 1204 DI 10.1016/S0017-9310(98)00248-8 PG 16 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 161KJ UT WOS:000078287600003 ER PT J AU Gao, XP Kocha, S Frank, AJ Turner, JA AF Gao, XP Kocha, S Frank, AJ Turner, JA TI Photoelectrochemical decomposition of water using modified monolithic tandem cells SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article; Proceedings Paper CT International Symposium on Hydrogen-Fuel Cell-Photovoltaic Systems I CY AUG 31-SEP 05, 1997 CL CANCUN, MEXICO ID SOLAR-CELLS AB Photovoltaic tandem cells, consisting of a gallium indium phosphide (GaInP2) homojunction grown epitaxially on a gallium arsenide (GaAs) homojunction with a GaAs tunnel diode interconnect, were modified with an additional top player of GaInP2. These cells were used as electrodes to photoelectrochemically decompose water into hydrogen and oxygen in 1M, 5M and 11M KOH electrolyte solutions. The hydrogen reaction was catalyzed at the semiconductor surface with a photoelectrochemically deposited thin layer of platinum and ruthenium. Gas chromatography and electrochemical experiments demonstrate that the modified tandem cells produce hydrogen and oxygen with a light-to-hydrogen conversion efficiency of up to 6%. Both the efficiency and the stability of these cells are discussed. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Air Prod & Chem Inc, Allentown, PA 18195 USA. Int Fuel Cells, South Windsor, CT 06074 USA. RP Turner, JA (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Schaff, William/B-5839-2009; Kocha, Shyam/E-4347-2010 NR 8 TC 26 Z9 26 U1 0 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD APR PY 1999 VL 24 IS 4 BP 319 EP 325 DI 10.1016/S0360-3199(98)00052-4 PG 7 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 192DZ UT WOS:000080064200005 ER PT J AU Bromberg, L Cohn, DR Rabinovich, A Surma, JE Virden, J AF Bromberg, L Cohn, DR Rabinovich, A Surma, JE Virden, J TI Compact plasmatron-boosted hydrogen generation technology for vehicular applications SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article ID LOW-EMISSION VEHICLES AB Onboard hydrogen generation using compact plasmatron devices could provide important new possibilities for reducing pollution from motor vehicles, making use of alternative fuels, and increasing engine efficiency. These improvements would involve the use of the plasmatron as a very small, rugged, rapid response and highly flexible means of electrical heating of gases. Plasmatron heating could be used to facilitate conversion of a wide range of hydrocarbon fuels into hydrogen-rich gas onboard a vehicle. Use of combinations of fuels is possible through potential transformation of a variety of fuels into hydrogen-rich gas. Another advantage of use of onboard plasmatron generation of hydrogen is that it could be used only when required and could be readily turned on and off. Preliminary experimental studies of plasmatron conversion of difficult-to-use alternative fuels (biofuels), iso-octane (representative of gasoline), and diesel fuel are described. Concepts for application to trucks and other heavy duty vehicles, sport utility vehicles and automobiles are discussed. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved. C1 MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Pacific NW Natl Lab, Richland, WA USA. RP Bromberg, L (reprint author), MIT, Plasma Sci & Fus Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 12 TC 48 Z9 49 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD APR PY 1999 VL 24 IS 4 BP 341 EP 350 DI 10.1016/S0360-3199(98)00013-5 PG 10 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 192DZ UT WOS:000080064200008 ER PT J AU Lightfoot, P Woodcock, DA Jorgensen, JD Short, S AF Lightfoot, P Woodcock, DA Jorgensen, JD Short, S TI Low thermal expansion materials: a comparison of the structural behaviour of La0.33Ti2(PO4)(3), Sr0.5Ti2(PO4)(3) and NaTi2(PO4)(3) SO INTERNATIONAL JOURNAL OF INORGANIC MATERIALS LA English DT Article DE ceramics; oxides; neuron diffraction; crystal structure; thermal expansion ID RAY-DIFFRACTION DATA AB Variable temperature neutron powder diffraction data have been used to examine the structural mechanism of unusual thermal expansion behaviour in La0.33Ti2(PO4)(3) (LaTP). These data are compared to those we have recently reported for the related systems NaTi2(PO4)(3) (NaTP) and Sr0.5Ti2(PO4)(3) (SrTP), which differ in the extent of occupation of the extra-Framework MI (La, Sr, Na) cation sites. The root cause of the unusual behaviour is ascribed to the differing expansivities of the occupied and vacant MI sites. This leads to cooperative rotations of TiO6 and PO4 polyhedra, which can be used to quantify and rationalise the overall anisotropic thermal expansion behaviour. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Lightfoot, P (reprint author), Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland. OI Lightfoot, Philip/0000-0001-7048-3982 NR 22 TC 24 Z9 24 U1 1 U2 23 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1466-6049 J9 INT J INORG MATER JI Int. J. Inorg. Mater. PD APR PY 1999 VL 1 IS 1 BP 53 EP 60 DI 10.1016/S1463-0176(99)00008-3 PG 8 WC Chemistry, Inorganic & Nuclear; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 298FT UT WOS:000086129200007 ER PT J AU Sewards, TV Sewards, MA AF Sewards, TV Sewards, MA TI Alpha-band oscillations in visual cortex: part of the neural correlate of visual awareness? SO INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY LA English DT Article DE temporal binding; temporal phase; consciousness; visual awareness; scene segmentation; synchronous oscillations; perceptual binding; visual cortex; magnocellular; parvocellular; cat; monkey ID REAL-MOTION CELLS; NEURONAL RESPONSES; MACAQUE MONKEY; AREA V4; PARVOCELLULAR CONTRIBUTIONS; CORTICAL AREAS; STRIATE CORTEX; CAT; SYNCHRONIZATION; COHERENT AB It was originally proposed that synchronized gamma-band oscillations in neurons of the visual cortex constitute the neural correlate of visual awareness. Two hypotheses are presented in this article: (a) both alpha-band and gamma-band oscillatory activity correspond to visual awareness; and (b) alpha-band activity occurs in the parvocellular processing pathway and gamma-band activity occurs in the magnocellular pathway, and the two modes of oscillation are correlated. It is further proposed that the frequency of the gamma-band oscillation in a group of neurons representing a particular visual scene segment is three times that of the alpha-band oscillation in the neurons representing the same segment. These hypotheses are discussed in relation to recent neurophysiological and psychophysiological experiments. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Sandia Res Ctr, Placitas, NM 87043 USA. Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA. RP Sewards, TV (reprint author), Sandia Res Ctr, 21 Perdiz Canyon Rd, Placitas, NM 87043 USA. NR 63 TC 29 Z9 30 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8760 J9 INT J PSYCHOPHYSIOL JI Int. J. Psychophysiol. PD APR PY 1999 VL 32 IS 1 BP 35 EP 45 DI 10.1016/S0167-8760(98)00062-2 PG 11 WC Psychology, Biological; Neurosciences; Physiology; Psychology; Psychology, Experimental SC Psychology; Neurosciences & Neurology; Physiology GA 179WD UT WOS:000079352200003 PM 10192006 ER PT J AU Hsieh, WA Deng, W Chang, WP Galvan, N Owens, CL Morrison, DP Gale, KL Lucas, JN AF Hsieh, WA Deng, W Chang, WP Galvan, N Owens, CL Morrison, DP Gale, KL Lucas, JN TI Alpha coefficient of dose-response for chromosome translocations measured by FISH in human lymphocytes exposed to chronic Co-60 gamma rays at body temperature SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID BIOLOGICAL DOSIMETRY; IONIZING-RADIATION; ABERRATIONS; RECONSTRUCTION; STABILITY; CURVE AB Purpose: To measure the alpha coefficient, the initial slope of the translocation dose-response curve, for Co-60 gamma-rays in human lymphocytes. Materials and methods: Human lymphocytes were exposed to 0, 0.32, 0.62 and 0.92 Gy of chronic Co-60 gamma-rays under conditions that reduce the metabolic stress to the cells. Chromosome translocation frequencies were measured using fluorescence In situ hybridization with a whole-chromosome probe cocktail specific for chromosomes 1, 2, 4 (orange) and 3, 5, 6 (green). Results: A total of 72 383 metaphases were analysed (33 429 in exposed cells) in two individuals. The shape of the dose-response curves for translocations was linear, and alpha coefficient was measured as 0.024 +/- 0.002 translocations per cell per Gy for the combined data for two 24 year old male donors. Conclusion: The alpha coefficients measured after chronic exposure were in good agreement with that reported in the literature for acute, low-dose exposure of human lymphocytes to Co-60 gamma-rays. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Natl Yang Ming Univ, Inst Publ Hlth, Taipei 112, Taiwan. Sichuan Inst Radiat Hlth & Protect, Chengdu, Sichuan, Peoples R China. AECL Res, Chalk River Labs, Chalk River, ON K0J 1J0, Canada. RP Lucas, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 18 TC 18 Z9 18 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD APR PY 1999 VL 75 IS 4 BP 435 EP 439 DI 10.1080/095530099140357 PG 5 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 186TQ UT WOS:000079745700005 PM 10331848 ER PT J AU Molina-Paris, C AF Molina-Paris, C TI Adiabatic interpretation of particle creation in a de Sitter universe SO INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS LA English DT Article; Proceedings Paper CT Quantum Gravity in the Southern Cone Conference CY JAN 07-10, 1998 CL CTR ATOMICO BARILOCHE, SAN CARLOS BARILO, ARGENTINA HO CTR ATOMICO BARILOCHE ID ENERGY-MOMENTUM TENSOR; QUANTUM FIELD-THEORY; STRESS TENSOR; SPACE-TIME; REGULARIZATION; RENORMALIZATION AB The choice of vacuum state for a quantum scalar field (massive and arbitrarily coupled to the gravitational field, with coupling constant xi) propagating in a de Sitter spacetime is discussed. The problem of finite-time initial conditions for the mode functions is analyzed, as well as how these determine the vacuum state of the quantum system. The principle guiding the choice of vacuum state is the following: one wants the vacuum contribution to the energy-momentum tensor to contain all the ultraviolet divergent terms, so that the particle creation terms are finite, and covariantly conserved. There is a suitable set of modes (instantaneous adiabatic basis) in which this splitting of the expectation value of the energy-momentum tensor can be carried out. Numerical results are presented for different initial times and the following values for the mass and the coupling constant: m = 0.6, xi = 1/6. The nature of the particle creation effect is described and its relationship to the concept of a horizon crossing time is shown. These numerical results imply that back reaction can be important and should be the subject of further research. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Molina-Paris, C (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-6 & T-8, Los Alamos, NM 87545 USA. NR 22 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 0020-7748 J9 INT J THEOR PHYS JI Int. J. Theor. Phys. PD APR PY 1999 VL 38 IS 4 BP 1273 EP 1297 DI 10.1023/A:1026622900666 PG 25 WC Physics, Multidisciplinary SC Physics GA 209RV UT WOS:000081063400016 ER PT J AU Taft, CA Guimaraes, TC Pavao, AC Lester, WA AF Taft, CA Guimaraes, TC Pavao, AC Lester, WA TI Adsorption and dissociation of diatomic molecules on transition-metal surfaces SO INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY LA English DT Review ID ANGLE-RESOLVED PHOTOEMISSION; ELECTRON-ENERGY LOSS; TEMPERATURE PROGRAMMED DESORPTION; RAY PHOTOELECTRON DIFFRACTION; DENSITY-FUNCTIONAL THEORY; MORSE-POTENTIAL ANALYSIS; SULFUR MODIFIED FE(100); SINGLE-CRYSTAL SURFACE; SMALL NICKEL CLUSTERS; QUANTUM MONTE-CARLO AB The interaction between transition-metal surfaces and simple diatomic molecules (CO, NO, H-2, N, and O-2) may lead to the breaking and making of chemical bonds and trigger important surface-catalysed reactions. We discuss the most common surface interaction and orientation models and consider the electronic structure of the transition metal, and the influence of structure, bonding and coordination of the diatomic molecule. We emphasize the importance of the tilted precursor in the dissociation of diatomic molecules on transition-metal surfaces. C1 Ctr Brasileiro Pesquisas Fis, BR-22290180 Rio De Janeiro, Brazil. Univ Fed Pernambuco, Dept Quim Fundamental, BR-50960450 Recife, PE, Brazil. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Ctr Brasileiro Pesquisas Fis, Rua Dr Xavier Sigaud 150,Urca, BR-22290180 Rio De Janeiro, Brazil. RI Pavao, Antonio/I-8002-2014 NR 441 TC 15 Z9 15 U1 2 U2 27 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0144-235X EI 1366-591X J9 INT REV PHYS CHEM JI Int. Rev. Phys. Chem. PD APR-JUN PY 1999 VL 18 IS 2 BP 163 EP 233 DI 10.1080/014423599229947 PG 71 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 232ER UT WOS:000082357600001 ER PT J AU Tolmasky, CF Wiegmann, A AF Tolmasky, CF Wiegmann, A TI Recovery of small perturbations of an interface for an elliptic inverse problem via linearization SO INVERSE PROBLEMS LA English DT Article ID ELECTRICAL-IMPEDANCE TOMOGRAPHY AB Electrical impedance tomography (EIT) is used to find the conductivity distribution inside a region using electrostatic measurements collected on the boundary of the region. We study a simple version of the general EIT problem, in which the medium has constant conductivity but might contain a buried object of unknown shape and different, but also constant, conductivity. Our linearization about an approximate shape of the buried object follows Kaup and Santosa and has the advantage that it is valid for large contrast in the conductivity. We present a procedure to reconstruct the object boundary in the case where we know the conductivities and the centre and radius of a good circular approximation of the object boundary, using analytic solutions to the forward problem for circular objects with known conductivity. Assuming that the unknown object boundary is star-shaped with respect to the centre of the circle and a small perturbation of the approximating circle, we develop a linearized relation between the output voltage data that result from fixed input currents, entering as parameters, and the interface, entering as variables. This relation is used to find the Fourier coefficients of the perturbation of the interface. At least two measurements are needed to determine all coefficients, and more can be used for a least-squares fit. The quality of the recovered perturbation depends on the input frequency and the frequencies of the perturbation. Low frequencies work best as input, and are most easily recovered, in that case even where the amplitude of the perturbation is not very small. Several dipoles, corresponding to very close pairs of electrodes to induce the current, can be used successfully as input as well. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Math, Berkeley, CA 94720 USA. RP Tolmasky, CF (reprint author), 10205 Greenbrier 202, Minnetonka, MN 55305 USA. NR 12 TC 13 Z9 13 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD APR PY 1999 VL 15 IS 2 BP 465 EP 487 DI 10.1088/0266-5611/15/2/008 PG 23 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 189PH UT WOS:000079913400010 ER PT J AU Soh, HT Yue, CP McCarthy, A Ryu, C Lee, TH Wong, SS Quate, CF AF Soh, HT Yue, CP McCarthy, A Ryu, C Lee, TH Wong, SS Quate, CF TI Ultra-low resistance, through-wafer via (TWV) technology and its applications in three dimensional structures on silicon SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article; Proceedings Paper CT 1998 International Conference on Solid State Devices and Materials (SSDM 98) CY SEP 07-10, 1998 CL HIROSHIMA, JAPAN SP Japan Soc Appl Physics & Techn, IEEE Elect Devices Soc DE through-wafer via; high aspect ratio etching; silicon etching; copper metallization; electro-plated photoresist; three dimensional inductor AB This paper presents an ultra-low resistance, high wiring density, through-wafer via (TWV) technology that is compatible with standard silicon wafer processing. Vias as small as 30 mu m by 30 mu m are fabricated through a 525 mu m thick wafer This results in an aspect ratio for the via that is greater than 17:1. Furthermore, the de resistance of a single via is less than 50 m Ohm. Key fabrication steps, including the silicon dry etch, copper metallization, and photoresist electroplating, are described in detail. As a demonstration of the potential applications of the TWV technology, a novel three dimensional inductor is designed and fabricated. For a 0.9-nH inductor, a quality factor of 18.5 is measured at 800 MHz. C1 Stanford Univ, Edward L Ginzton Lab, Stanford, CA 94305 USA. Stanford Univ, Ctr Integrated Syst, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Soh, HT (reprint author), Stanford Univ, Edward L Ginzton Lab, Stanford, CA 94305 USA. NR 9 TC 29 Z9 29 U1 1 U2 7 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO, 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD APR PY 1999 VL 38 IS 4B BP 2393 EP 2396 DI 10.1143/JJAP.38.2393 PG 4 WC Physics, Applied SC Physics GA 241FD UT WOS:000082871300046 ER PT J AU Munkholm, A Brennan, S AF Munkholm, A Brennan, S TI Influence of miscut on crystal truncation rod scattering SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID X-RAY-SCATTERING; STEPPED SURFACES; DIFFRACTION; ROUGHNESS; SIO2/SI(001); MULTILAYERS; REFLECTION; INTERFACE AB X-rays can be used to measure the roughness of a surface by the study of crystal truncation rod scattering. It is shown that for a simple cubic lattice the presence of a miscut surface with a regular step array has no effect on the scattered intensity of a single rod and that a distribution of terrace widths on the surface is shown to have the same effect as adding roughness to the surface. For a perfect crystal without miscut, the scattered intensity is the sum of the intensity from all the rods with the same in-plane momentum transfer. For all real crystals, the scattered intensity is better described as that from a single rod. It is shown that data-collection strategies must correctly account for the sample miscut or there is a potential for improperly measuring the rod intensity. This can result in an asymmetry in the rod intensity above and below the Bragg peak, which can be misinterpreted as being due to a relaxation of the surface. The calculations presented here are compared with data for silicon (001) wafers with 0.1 and 4 degrees miscuts. C1 Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Munkholm, A (reprint author), Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 19 TC 14 Z9 14 U1 3 U2 13 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD APR 1 PY 1999 VL 32 BP 143 EP 153 DI 10.1107/S0021889898005159 PN 2 PG 11 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 190TV UT WOS:000079981900001 ER PT J AU Zhao, YS Von Dreele, RB Weidner, DJ AF Zhao, YS Von Dreele, RB Weidner, DJ TI Correction of diffraction optics and P-V-T determination using thermoelastic equations of state of multiple phases SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID HIGH-TEMPERATURES; MGO AB This report discusses a new method to determine experimental pressure-volume-temperature (P-V-T) data and to correct misalignment of diffraction optics using thermoelastic equations of state of multiple phases. Analytical approaches as well as numerical approaches are presented for the technique. A number of phase combinations yield the best experimental result and the whole-pattern Rietveld and/or Le Bail refinement of diffraction patterns of multiple phases is a significant aspect of the technique. Specific examples indicate that the corrected pressure, temperature and diffraction optics are robust. Errors are estimated from the uncertainties of the measured cell dimensions. The error propagation for different experimental cases is discussed, along with the conditions and limitations of the method. This technique for P-V-T determination and the correction of diffraction optics is crucial for experiments conducted under extreme conditions of high pressure, high temperature and dynamic reactions. C1 Univ Calif Los Alamos Natl Lab, LANSCE, Los Alamos, NM 87545 USA. SUNY Stony Brook, CHIPR & Mineral Phys Inst, Stony Brook, NY 11794 USA. RP Zhao, YS (reprint author), Univ Calif Los Alamos Natl Lab, LANSCE, MS-H805, Los Alamos, NM 87545 USA. RI Lujan Center, LANL/G-4896-2012 NR 14 TC 4 Z9 4 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD APR 1 PY 1999 VL 32 BP 218 EP 225 DI 10.1107/S0021889898011935 PN 2 PG 8 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 190TV UT WOS:000079981900011 ER PT J AU Stephens, PW AF Stephens, PW TI Phenomenological model of anisotropic peak broadening in powder diffraction SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID RIETVELD REFINEMENT; RAY; STRAIN; SIZE AB Anisotropic line-shape broadening (peak width which is not a smooth function of d-spacing) is frequently observed in powder diffraction patterns, and can be a source of considerable difficulty for whole-pattern fitting or Rietveld analysis. A model of the multi-dimensional distribution of lattice metrics within a powder sample is developed, leading naturally to a few parameters which can be varied to achieve optimal line-shape fits. Conditions on these parameters are derived for all crystal systems, and the method is illustrated with two examples: sodium p-hydroxybenzoate and rubidium fulleride. C1 Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Stephens, PW (reprint author), Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. NR 26 TC 688 Z9 691 U1 3 U2 71 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD APR 1 PY 1999 VL 32 BP 281 EP 289 DI 10.1107/S0021889898006001 PN 2 PG 9 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 190TV UT WOS:000079981900017 ER PT J AU Laaziri, K Roberson, JL Roorda, S Chicoine, M Kycia, S Wang, J Moss, SC AF Laaziri, K Roberson, JL Roorda, S Chicoine, M Kycia, S Wang, J Moss, SC TI Quantitative treatment for extracting coherent elastic scattering from X-ray scattering experiments SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB A fitting procedure for separating the inelastic and elastic contributions to the total scattering in diffuse-scattering experiments at high energy using energy-dispersive X-ray techniques is presented. An asymmetric peak function is used to model the elastic peak. The inelastic scattering peak is modeled using a theoretical Compton profile, calculated using the impulse approximation (Hartree-Fock wave functions were used), convoluted with the detector resolution. This procedure, which requires only two free parameters, is shown to be extremely effective in extracting the integrated elastic intensity of coherent scattering at each wave vector, even at low scattering angles where the Compton scattering is not well resolved. C1 Univ Montreal, Dept Phys, Grp Rech Phys & Technol Couches Minces, Montreal, PQ H3C 3J7, Canada. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Cornell Univ, Wilson Lab, CHESS, Ithaca, NY 14853 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. RP Laaziri, K (reprint author), Univ Montreal, Dept Phys, Grp Rech Phys & Technol Couches Minces, CP 6128 Succursale Ctr Ville, Montreal, PQ H3C 3J7, Canada. RI Roorda, Sjoerd/N-2604-2014 NR 7 TC 6 Z9 6 U1 3 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD APR 1 PY 1999 VL 32 BP 322 EP 326 DI 10.1107/S0021889898014071 PN 2 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 190TV UT WOS:000079981900022 ER PT J AU Taha, H AF Taha, H TI Modifying a mesoscale meteorological model to better incorporate urban heat storage: A bulk-parameterization approach SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID OZONE AIR-QUALITY; SURFACE-TEMPERATURE; BOUNDARY-LAYER; CTTC MODEL; IMPACTS; IMPROVEMENT; ISLAND; BASIN; AREA AB A simple bulk-parameterization scheme is implemented in modifying a mesoscale meteorological model to better incorporate urban heat storage. The objective is to improve the quantification of the fluxes associated with heat storage change and to more explicitly account for the integrated effect of urban canopy layer fluxes on the overlying boundary layer. The approach involves integrating an Objective Hysteresis Model with a meteorological model, which, in this case, is the Colorado Stare University Mesoscale Model (CSUMM). When the resulting modified version of the model (MM) is applied to the Atlanta, Georgia, region, larger daytime urban heat islands are predicted (similar to 1.5 degrees C larger) than with the nonmodified version of CSUMM. The largest simulated summer daytime Atlanta hear island for the modeling episode of 25-27 July is 1.4 degrees C with CSUMM and 2.9 degrees C with MM. The impacts of surface modifications, such as changes in urban albedo, on air temperature are slightly larger in MM than in CSUMM. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Heat Isl Project, Berkeley, CA 94720 USA. RP Taha, H (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Heat Isl Project, MS 90-2000, Berkeley, CA 94720 USA. EM hgtaha@lbl.gov NR 37 TC 72 Z9 86 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1999 VL 38 IS 4 BP 466 EP 473 DI 10.1175/1520-0450(1999)038<0466:MAMMMT>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 186VX UT WOS:000079752300007 ER PT J AU Khanna, S Atalay, M Laaksonen, DE Gul, M Roy, S Sen, CK AF Khanna, S Atalay, M Laaksonen, DE Gul, M Roy, S Sen, CK TI alpha-lipoic acid supplementation: tissue glutathione homeostasis at rest and after exercise SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE thioctic acid; thiol; nutrition; lipid peroxidation; antioxidant ID LIQUID-CHROMATOGRAPHY; MEMBRANE-TRANSPORT; OXIDATIVE STRESS; ANTIOXIDANT; DEFICIENCY; TRANSCRIPTION; METABOLISM; CYSTINE; MUSCLE; PLASMA AB Antioxidant nutrients have demonstrated potential in protecting against exercise-induced oxidative stress. alpha-Lipoic acid (LA) is a proglutathione dietary supplement that is known to strengthen the antioxidant network. We studied the effect of intragastric LA supplementation (150 mg/kg, 8 wk) on tissue LA levels, glutathione metabolism, and lipid peroxidation in rats at rest and after exhaustive treadmill exercise. LA supplementation increased the level of free LA in the red gastrocnemius muscle and increased total glutathione levels in the liver and blood. The exercise-induced decrease in heart glutathione S-transferase activity was prevented by LA supplementation. Exhaustive exercise significantly increased thiobarbituric acid-reactive substance levels in the liver and red gastrocnemius muscle. LA supplementation protected against oxidative lipid damage in the heart, liver, and red gastrocnemius muscle. This study reports that orally supplemented LA is able to favorably influence tissue antioxidant defenses and counteract lipid peroxidation at rest and in response to exercise. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Biol Technol Sect, Life Sci Addit,EETD, Berkeley, CA 94720 USA. Univ Kuopio, Dept Physiol, Fac Med, FIN-70211 Kuopio, Finland. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Sen, CK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Biol Technol Sect, Life Sci Addit,EETD, Bldg 20A,Rm 251 C,Mail Stop 3200, Berkeley, CA 94720 USA. RI Sen, Chandan/A-8762-2013; Khanna, Savita/E-3378-2011; gul, mustafa/G-5842-2011; Roy, sashwati/E-3990-2011 OI gul, mustafa/0000-0002-0042-890X; NR 40 TC 60 Z9 64 U1 0 U2 5 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD APR PY 1999 VL 86 IS 4 BP 1191 EP 1196 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 191EU UT WOS:000080010200013 PM 10194202 ER PT J AU Weier, HUG Munne, S Fung, JL AF Weier, HUG Munne, S Fung, JL TI Patient-specific probes for preimplantation genetic diagnosis of structural and numerical aberrations in interphase cells SO JOURNAL OF ASSISTED REPRODUCTION AND GENETICS LA English DT Article DE translocation; infertility; in vitro fertilization; multicolor in situ hybridization; DNA probe; interphase cells ID IN-SITU HYBRIDIZATION; INSITU HYBRIDIZATION; CHROMOSOME-ABNORMALITIES; PRECONCEPTION DIAGNOSIS; EMBRYOS; DNA; TRANSLOCATIONS; ANEUPLOIDY; FISH; MAP AB Purpose: Our purpose was to evaluate the utility of translocation breakpoint-spanning DNA probes for prenatal genetic diagnosis of structural and numerical chromosome aberrations in interphase cells. Methods: Breakpoint-spanning translocation probes were isolated from large insert DNA libraries and labeled so that the breakpoint regions were stained in different colors. Hybridization conditions were optimized using blastomeres biopsied from donated embryos. Probes were then applied to analyze patient blastomeres. Results: We prepared translocation breakpoint-specific probes for 18 in vitro fertilization patients. Here. we describe the preparation of probes for two patients carrying balanced translocations involving chromosome 11 [t(11;22)(q23;q11), t(6;11)(p22.1;p15.3)]. The breakpoint cloning procedure could be accomplished in about 3-5 weeks. Additional time was needed to optimize probes. Application of probes demonstrated numerical as well as structural abnormalities. Conclusions: Breakpoint-spanning probes allow chromosome analysis in interphase cells as required for preimplantation genetic diagnosis screening of blastomeres. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Life Sci Div 74 157, Dept Subcellular Struct, Berkeley, CA 94720 USA. RP Weier, HUG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Life Sci Div 74 157, Dept Subcellular Struct, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Fung, John/A-2679-2012; OI Munne, Santiago/0000-0002-1088-5565 NR 36 TC 21 Z9 23 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1058-0468 J9 J ASSIST REPROD GEN JI J. Assist. Reprod. Genet. PD APR PY 1999 VL 16 IS 4 BP 182 EP 191 DI 10.1023/A:1020360706317 PG 10 WC Genetics & Heredity; Obstetrics & Gynecology; Reproductive Biology SC Genetics & Heredity; Obstetrics & Gynecology; Reproductive Biology GA 188GW UT WOS:000079839300005 PM 10224561 ER PT J AU Price, LB Hugh-Jones, M Jackson, PJ Keim, P AF Price, LB Hugh-Jones, M Jackson, PJ Keim, P TI Genetic diversity in the protective antigen gene of Bacillus anthracis SO JOURNAL OF BACTERIOLOGY LA English DT Article ID LETHAL FACTOR; TOXIN GENES; STRAINS AB Bacillus anthracis is a gram-positive spore-forming bacterium that causes the disease anthrax, The anthrax toxin contains three components, including the protective antigen (PA), which binds to eucaryotic cell surface receptors and mediates the transport of toxins into the cell. In this study, the entire 2,294-nucleotide protective antigen gene (pag) was sequenced from 26 of the most diverse B. anthracis strains to identify potential variation in the toxin and to further our understanding of B. anthracis evolution. Five point mutations, three synonymous and two missense, were identified. These differences correspond to six different haploid types, which translate into three different amino acid sequences. The two amino acid changes were shown to be located in an area near a highly antigenic region critical to lethal factor binding. Nested primers were used to amplify and sequence this same region of pag from necropsy samples taken from victims of the 1979 Sverdlovsk incident. This investigation uncovered five different alleles among the strains present in the tissues, including two not seen in the 26-sample survey. One of these two alleles included a novel missense mutation, again located just adjacent to the highly antigenic region. Phylogenetic (cladistic) analysis of the pag corresponded with previous strain grouping based on chromosomal variation, suggesting that plasmid evolution in B, anthracis has occurred with little or no horizontal transfer between the different strains. C1 No Arizona Univ, Dept Biol Sci, Flagstaff, AZ 86011 USA. Louisiana State Univ, Sch Vet Med, Dept Epidemiol & Community Hlth, Baton Rouge, LA 70803 USA. Univ Calif Los Alamos Natl Lab, Environm Mol Biol Grp, Los Alamos, NM 87545 USA. RP Keim, P (reprint author), No Arizona Univ, Dept Biol Sci, Box 5640, Flagstaff, AZ 86011 USA. RI Keim, Paul/A-2269-2010 NR 12 TC 68 Z9 77 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD APR PY 1999 VL 181 IS 8 BP 2358 EP 2362 PG 5 WC Microbiology SC Microbiology GA 186BH UT WOS:000079706600007 PM 10197996 ER PT J AU Peterka, DS Ahmed, M Suits, AG Wilson, KJ Korkin, A Nooijen, M Bartlett, RJ AF Peterka, DS Ahmed, M Suits, AG Wilson, KJ Korkin, A Nooijen, M Bartlett, RJ TI Unraveling the mysteries of metastable O-4* SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COUPLED-CLUSTER METHOD; CYCLOTETRAOXYGEN; OXYGEN; STATE; DISSOCIATION; D1-PI-G; O-4 AB A recent report from our laboratory described 1+1 resonant photoionization spectra of an energetic, metastable O-4 species produced in a dc discharge [Bevsek et al., Faraday Discuss. 108, 131 (1998)]. Although a definitive assignment of the spectra was lacking, the long-predicted covalent forms of O-4, either cyclic (D-2d) or "pinwheel'' (D-3h), were adduced as possible candidates. We here present rotationally resolved photoionization spectra, photoelectron spectra, and ab initio calculations providing strong evidence for the identity of this species as a novel complex between a ground state O-2 molecule and one in the c((1)Sigma(u)(-)) state, which is excited via an allowed transition to the 1((1)Pi(g)) valence state. The latter then couples to the d((1)Pi(g)) Rydberg state, shifted in energy owing to the presence of the adjacent O-2 molecule, from which it then ionizes. The results underscore the potential importance of the fully allowed but overlooked 1((1)Pi(g)) <--c((1)Sigma(u)(-)) electronic transition in O-2 in the near ultraviolet, and provide a simple interpretation of puzzling results in an earlier study of electron transfer to O-4(+) [H. Helm and C. W. Walter, J. Chem. Phys. 98, 5444 (1993)]. (C) 1999 American Institute of Physics. [S0021-9606(99)01613-X]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA. RP Suits, AG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. EM agsuits@lbl.gov RI Ahmed, Musahid/A-8733-2009; Bartlett, Rodney/F-6781-2011 OI Bartlett, Rodney/0000-0003-3865-9639 NR 23 TC 32 Z9 33 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 APR 1 PY 1999 VL 110 IS 13 BP 6095 EP 6098 DI 10.1063/1.478515 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 181AT UT WOS:000079419000002 ER PT J AU Halley, JW Smith, BB Walbran, S Curtiss, LA Rigney, RO Sutjianto, A Hung, NC Yonco, RM Nagy, Z AF Halley, JW Smith, BB Walbran, S Curtiss, LA Rigney, RO Sutjianto, A Hung, NC Yonco, RM Nagy, Z TI Theory and experiment on the cuprous-cupric electron transfer rate at a copper electrode SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; TEMPERATURE-DEPENDENCE; INTERFACE; WATER; SIMULATION; KINETICS; POTENTIALS; CHARGE; GOLD; IONS AB We describe results of experiment and theory of the cuprous-cupric electron transfer rate in an aqueous solution at a copper electrode. The methods are similar to those we reported earlier for the ferrous-ferric rate. The comparison strongly suggests that, in marked distinction to the ferrous-ferric case, the electron transfer reaction is adiabatic. The model shows that the activation barrier is dominated by the energy required for the ion to approach the electrode, rather than by the energy required for rearrangement of the solvation shell, also in sharp distinction to the case of the ferric-ferrous electron transfer at a gold electrode. Calculated activation barriers based on this image agree with the experimental results reported here. (C) 1999 American Institute of Physics. [S0021-9606(99)70410-1]. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Natl Renewable Energy Lab, Golden, CO USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Wheaton Coll, Dept Chem, Wheaton, IL 60187 USA. RP Halley, JW (reprint author), Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. NR 68 TC 14 Z9 14 U1 1 U2 5 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 APR 1 PY 1999 VL 110 IS 13 BP 6538 EP 6552 DI 10.1063/1.478557 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 181AT UT WOS:000079419000046 ER PT J AU Glaesemann, KR Gordon, MS AF Glaesemann, KR Gordon, MS TI Evaluation of gradient corrections in grid-free density functional theory SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID EXACT-EXCHANGE; ENERGY; APPROXIMATIONS C1 Iowa State Univ, Dept Chem, US DOE, Ames Lab, Ames, IA 50011 USA. RP Glaesemann, KR (reprint author), Iowa State Univ, Dept Chem, US DOE, Ames Lab, Ames, IA 50011 USA. RI Glaesemann, Kurt/B-4841-2010; OI Glaesemann, Kurt/0000-0002-9512-1395 NR 23 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1999 VL 110 IS 13 BP 6580 EP 6582 DI 10.1063/1.478559 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 181AT UT WOS:000079419000049 ER PT J AU Chen, WYC Louck, JD AF Chen, WYC Louck, JD TI Enumeration of cubic graphs by inclusion-exclusion SO JOURNAL OF COMBINATORIAL THEORY SERIES A LA English DT Article AB We use the principle of inclusion and exclusion to enumerate labeled cubic graphs, without resort to the superposition theory of Read. This work; was motivated by the cubic array representation of cubic graphs in the studies of generating functions of 3n - j coefficients in angular momentum theory. (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Nankai Univ, Ctr Combinator, Tianjin 300071, Peoples R China. RP Chen, WYC (reprint author), Univ Calif Los Alamos Natl Lab, T-7,Mail Stop B284, Los Alamos, NM 87545 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0097-3165 J9 J COMB THEORY A JI J. Comb. Theory Ser. A PD APR PY 1999 VL 86 IS 1 BP 151 EP 157 DI 10.1006/jcta.1998.2923 PG 7 WC Mathematics SC Mathematics GA 184AL UT WOS:000079587100009 ER PT J AU Oostrom, M Hofstee, C Walker, RC Dane, JH AF Oostrom, M Hofstee, C Walker, RC Dane, JH TI Movement and remediation of trichloroethylene in a saturated heterogeneous porous medium 1. Spill behavior and initial dissolution SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE DNAPL; remediation; dissolution; trichloroethylene; plume behavior ID NONAQUEOUS-PHASE LIQUID; DENSE CHLORINATED SOLVENTS; MASS-TRANSFER CHARACTERISTICS; SUBSURFACE SYSTEMS; MULTIPHASE FLOW; MODEL; GROUNDWATER; TRANSPORT; POOLS; PLUMES AB An intermediate-scale flow cell experiment was conducted to study the flow of liquid and the transport of dissolved trichloroethylene (TCE) in a saturated, heterogeneous porous medium system. The 1.67-m long by 1.0-m high by 0.05-m wide flow cell was packed with three layers and five lenses consisting of four different sands. All lenses and layers had horizontal interfaces, except the lowest interface, which was pointed down in the middle. Groundwater flow was imposed by manipulating the water levels in two head chambers. Over 500 mi of dyed TCE was allowed to infiltrate at a constant rate into the porous medium from a narrow source located on the surface. A dual-energy gamma radiation system was used to determine TCE saturations at 1059 locations. Fluid samples were collected from 20 sampling ports to determine dissolved TCE concentrations. The TCE migrated downwards in the form of several relatively narrow (3-8 mm) fingers. Visual observations and measured TCE saturations indicated that the spilled TCE accumulated on top of, but did not penetrate into, fine-grained sand lenses and layers but that some TCE infiltrated into medium-grained sand lenses. This behavior is a result of the different nonwetting-fluid entry and permeability values of the sands. Most of the TCE finally pooled on top of a fine-grained sand layer located in the bottom part of the flow cell. A multifluid code (STOMP: subsurface transport over multiple phases), accounting for TCE entrapment, was used to simulate the movement of liquid TCE. Using independently obtained hydraulic parameter values, the code was able to qualitatively predict the observed behavior at the interfaces of the lenses and sand layers. Simulation results suggest that most of the liquid TCE at the lowest interface was in free, continuous form, while most of the other TCE remaining in the flow cell was entrapped and discontinuous. A simple pool dissolution model was used to predict observed dissolved TCE concentrations. Results show that the measured concentrations could only be predicted with unrealistically high transverse dispersivity values. The observed TCE concentrations are a result of a combination of entrapped and pool dissolution. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Technol Div, Richland, WA 99352 USA. Univ Stuttgart, WAREM, D-70550 Stuttgart, Germany. Auburn Univ, Dept Civil Engn, Auburn, AL 36849 USA. Auburn Univ, Dept Agron & Soils, Auburn, AL 36849 USA. RP Oostrom, M (reprint author), Pacific NW Natl Lab, Environm Technol Div, POB 999,MS K9-33, Richland, WA 99352 USA. EM mart.oostrom@pnl.gov NR 44 TC 52 Z9 54 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD APR PY 1999 VL 37 IS 1-2 BP 159 EP 178 DI 10.1016/S0169-7722(98)00153-3 PG 20 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 180QN UT WOS:000079396800008 ER PT J AU Oostrom, M Hofstee, C Walker, RC Dane, JH AF Oostrom, M Hofstee, C Walker, RC Dane, JH TI Movement and remediation of trichloroethylene in a saturated, heterogeneous porous medium 2. Pump-and-treat and surfactant flushing SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE remediation; pump-and-treat; surfactant flushing; DNAPL; trichloroethylene; plume behavior ID RESIDUAL TETRACHLOROETHYLENE; SOIL COLUMNS; TRANSPORT; AQUIFER AB An intermediate-scale flow cell experiment was conducted to remove a liquid trichloroethylene (TCE) spill from a saturated, heterogeneous porous medium using pump-and-treat (P&T) as well as surfactant flushing (SF) techniques. Dissolved TCE concentrations were measured at 20 locations, while fluid saturations were obtained with a dual-energy gamma scanner. The behavior of the TCE spill has been described by Oostrom et al. (1998b) [Oostrom, M., Hofstee, C., Walker, R.C., Dane, J.H., 1998b. Movement and remediation of TCE in a saturated heterogeneous porous medium: I. Spill behavior and initial dissolution, this issue.]. A total of six alternating P&T and SF periods were used to remediate the flow cell. A two-well system, consisting of an injection and an extraction well, was used during the first five remediation periods. For the last SF period, a three-well system was employed with two injection wells and one extraction well. During the first P&T period, most entrapped TCE was removed, but TCE saturations in a substantial pool on top of a fine-grained sand layer were largely unaffected. During the first SF period, a dense plume was formed containing solubilized TCE which partially sank into the fine-grained sand. In addition, unstable fingers developed below the liquid TCE in the pool. In several samples, small TCE droplets were found, indicating mobilization of TCE. Most of the samples with concentrations larger than 5000 ppm had a milky, emulsion-like appearance. The SF considerably reduced the amount of TCE in the pool on top of the fine-grained sand. During the second P&T period, plume sinking and instabilities were not observed. After starting the second SF period, some unstable fingering and plume sinking resumed, starting at the upstream end of the TCE in the pool. The saturation distribution obtained after the second SF period was quite similar to the one obtained after the first SF period, indicating that additional removal of TCE through SF was difficult as a result of the limited accessibility of the TCE in the pool. A gamma scan, obtained after three weeks of pumping using the three-well configuration, shows that all the liquid TCE had been removed from the coarse-grained sand. Computations based on extraction rates and measured TCE concentrations show that only about 60% of the injected TCE was removed from the cell during the experiment. Part of the missing 40% might have moved downwards into the fine-grained sand as a result of pure phase mobilization. The experimental results suggest that besides the positive effects of solubilization, possible detrimental processes such as pure phase mobilization and dense aqueous-phase plume behavior should be considered during SF. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Technol Div, Richland, WA 99352 USA. Univ Stuttgart, WAREM, D-70550 Stuttgart, Germany. Auburn Univ, Dept Civil Engn, Auburn, AL 36849 USA. Auburn Univ, Dept Agron & Soils, Auburn, AL 36849 USA. RP Oostrom, M (reprint author), Pacific NW Natl Lab, Environm Technol Div, POB 999,MS K9-33, Richland, WA 99352 USA. NR 18 TC 38 Z9 40 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD APR PY 1999 VL 37 IS 1-2 BP 179 EP 197 DI 10.1016/S0169-7722(98)00154-5 PG 19 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 180QN UT WOS:000079396800009 ER PT J AU Horstemeyer, MF Baskes, MI AF Horstemeyer, MF Baskes, MI TI Atomistic finite deformation simulations: A discussion on length scale effects in relation to mechanical stresses SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID MOLECULAR-DYNAMICS SIMULATIONS; EMBEDDED-ATOM METHOD; LATTICE-DEFECTS; HYDROGEN; SYSTEMS; NICKEL AB In this study, atomistic finite deformtation calculations employing the Embedded Atom Method show three items of interest related to continuum field theory. First, a spatial size scale effect on the yield stress is found. In these calculations, mechanical yield point occurred from dislocation initiation at the edge of the numerical specimens. The spatial size scale continued to affect the plastic response up to strains of 30 percent in simple shear for nickel oriented at < 011 >. The second point is related to the continuum mechanics observation about oscillating global shear stress under simple shear conditions is shown to dampen as the spatial size scale increases. As the spatial length scale increases, the continuum rotational effect coupled with the increase in dislocation population reduces the oscillatory behavior. This confirms the notion proposed by Bammann and Aifantis (1987) in that when more dislocations are initiated with different orientations of the Burger's vectors then the oscillations decrease. Finally, a length scale bridging idea is proposed by relating a continuum single degree of freedom loss coefficient, which relates the plastic energy to the total strain energy, to varying sizes of blocks of atoms. This study illustrates the usefulness of employing the Embedded Atom Method to study mechanisms related to continuum mechanics quantities. C1 Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94551 USA. RP Horstemeyer, MF (reprint author), Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94551 USA. OI Horstemeyer, Mark/0000-0003-4230-0063 NR 21 TC 74 Z9 78 U1 0 U2 13 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 114 EP 119 DI 10.1115/1.2812354 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100002 ER PT J AU Moriarty, JA Xu, W Soderlind, P Belak, J Yang, LH Zhu, J AF Moriarty, JA Xu, W Soderlind, P Belak, J Yang, LH Zhu, J TI Atomistic Simulations for multiscale modeling in bcc metals SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID CENTERED CUBIC METALS; TRANSITION-METALS; SCREW DISLOCATIONS; GRAIN-BOUNDARIES; INTERATOMIC POTENTIALS; PEIERLS STRESS; MO; STRENGTH; FORCES; CORE AB Quantum-based atomistic simulations are being used to study fundamental deformation and defect properties relevant to the multiscale modeling of plasticity plasticity in bce metals at both ambient and extreme conditions. Ab initio electronic-structure calculations on the elastic and ideal-strength properties of Ta and Mo help constrain and validate many-body interatomic potentials used to study grain boundaries and dislocations. The predicted Sigma 5 (310) [100] grain boundary structure for Mo has recently been confirmed in HREM measurements. The core structure, gamma surfaces, Peierls stress, and kink-pair formation energies associated with the motion of a/2 < 111 > screw dislocations in Ta and Mo have also been calculated. Dislocation mobility and dislocation junction formation and breaking are currently under investigation. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Moriarty, JA (reprint author), Synopsys Inc, 700 E Middlefield Rd, Mt View, CA 94043 USA. NR 26 TC 25 Z9 25 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 120 EP 125 DI 10.1115/1.2812355 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100003 ER PT J AU Shastry, V de la Rubia, TD AF Shastry, V de la Rubia, TD TI The interaction between point defects and edge dislocation in BCC iron SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID IRRADIATION CREEP; INTERSTITIALS AB We present results of atomistic simulations of the interaction between self interstitial atoms and vacancies with edge dislocations in BCC iron. The calculations are carried out using molecular dynamics with an energy minimization scheme based on the quasi-Newton approach and use the Finnis-Sinclair interatomic potential for BCC iron developed by Ackland et al. Large anisotropy in the strain field of self interstitials is observed and it causes strong interaction with edge dislocations even when the defect is located on the dislocation glide plane. For vacancies, the relaxation volume is smaller and much more isotropic, which results in a far weaker interaction with the dislocation. A temperature dependent capture radius for vacancies and self interstitials is extracted from the simulations. The difference between the capture radii of vacancies and self interstitials Is used to define the sink strength of the dislocation. Large deviations are observed from the predictions of elasticity based on treating point defects as isotropic dilatational centers. Further, the capture radius of edge dislocations in BCC iron is observed to be small and is of the or-der of 1-3 nm for self interstitials. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94551 USA. RP Shastry, V (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, POB 5508, Livermore, CA 94551 USA. NR 12 TC 8 Z9 8 U1 0 U2 5 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 126 EP 128 DI 10.1115/1.2812356 PG 3 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100004 ER PT J AU Huang, HC Ghoniem, N de la Rubia, TD Rhee, M Zbib, H Hirth, J AF Huang, HC Ghoniem, N de la Rubia, TD Rhee, M Zbib, H Hirth, J TI Stability of dislocation short-range reactions in BCC crystals SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID DEFORMATION; SIMULATION; DYNAMICS; SLIP AB The stability of short-range reactions between two dislocations of parallel line vectors which glide on two parallel slip planes in BCC crystals is determined. The two dislocations are assumed to be infinitely long, and their interaction is treated as elastic. The interaction and self-energies are both computed for dynamically moving dislocations, where the dependence on dislocation velocity is taken into account. The stability of the reaction is determined as a function of the following phase space variables: relative angle, relative speed, dislocation mobility, Burgers vector, separation of slip planes, and external force. Our results indicate that the dynamic formation of dislocation dipoles or tilt wall embryos occurs only over a small range of the investigated phase space. Inertial effects are shown to be important at close separation, because of the large force between the two dislocations comprising the dipole or tilt wall embryo. We find that destabilization of the dislocation dipoles or tilt wall embryos is enhanced by externally applied stresses or by stress fields of neighboring dislocations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90024 USA. Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. RP Huang, HC (reprint author), Hong Kong Polytech Univ, Dept Engn Mech, Hong Kong, Peoples R China. RI Huang, Hanchen/A-9323-2008; Ghoniem, Nasr/A-9799-2008 NR 20 TC 19 Z9 19 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 143 EP 150 DI 10.1115/1.2812359 PG 8 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100007 ER PT J AU Harley, EJ Miller, MP Bammann, DJ AF Harley, EJ Miller, MP Bammann, DJ TI Experimental study of internal variable evolution in SS304L, at multiple rates and temperatures SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID 304 STAINLESS-STEEL; PLASTIC RELAXATION; COPPER-SILICA; STRAIN; BEHAVIOR; METALS AB Most metals exhibit a deformation-induced uniaxial yield strength asymmetry. Interpreted within the context of macroscale viscoplastic models, it is conventional to describe this yield strength asymmetry with an isotropic hardening variable kappa, and a kinematic hardening variable, alpha. The focus of this work was to conduct a series of reverse yield experiments to directly measure the evolution of alpha and kappa in 304L stainless steel (SS304L) over large ranges of temperatures and strain rates. We found that the material exhibited inelastic behavior immediately on changing, the straining direction. We discussed the ramifications of this behavior on our goal to directly measure alpha and kappa within the context of an isotropic/kinematic hardening model framework. We also explored the capability of the model to simulate the behavior of SS304L under differ ent loading conditions across a wide range of temperatures and strain rates. C1 Cornell Univ, Sibley Sch Mech & Aerosp Engn, Ithaca, NY 14853 USA. Sandia Natl Labs, Ctr Mat & Mech, Livermore, CA 94551 USA. RP Harley, EJ (reprint author), Cornell Univ, Sibley Sch Mech & Aerosp Engn, Ithaca, NY 14853 USA. RI Miller, Matthew/D-7903-2017 NR 36 TC 2 Z9 2 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 162 EP 171 DI 10.1115/1.2812362 PG 10 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100010 ER PT J AU Briant, CL Lassila, DH AF Briant, CL Lassila, DH TI The effect of tungsten an the mechanical properties of tantalum SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV ID SINGLE-CRYSTALS; DISLOCATION AB This paper reports a study of the mechanical behavior of Ta and Ta-W alloys. The results show that tungsten additions increase the yield strength and the rate of work hardening of tantalum These additions also cause a change in the deformed microstructure from one that is primarily cellular to one that consists mostly of dislocation tangles. It is proposed that the increase in yield strength arises from solid solution hardening and that the increase in the work hardening can be cor-related with an increase in the density and arrangement of dislocations present in the material. C1 Brown Univ, Div Engn, Providence, RI 02912 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Briant, CL (reprint author), Brown Univ, Div Engn, Providence, RI 02912 USA. NR 17 TC 7 Z9 8 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 172 EP 177 DI 10.1115/1.2812363 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100011 ER PT J AU Schwartz, AJ King, WE Campbell, GH Stolken, JS Lassila, DH Sun, S Adams, BL AF Schwartz, AJ King, WE Campbell, GH Stolken, JS Lassila, DH Sun, S Adams, BL TI Orientation imaging microscopy investigation of the compression deformation of a [011] Ta single crystal SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Symposium on Multi-Scale Modeling of Deformation and Fracture, at the 35th Technical Annual Meeting of the Society-of-Engineering-Science CY SEP 27-30, 1998 CL WASHINGTON STATE UNIV, PULLMAN, WASHINGTON HO WASHINGTON STATE UNIV AB High-purity tantalum single crystal cylinders oriented with [011] parallel to the cylinder axis were deformed 10, 20, and 30 percent in compression. The samples took on art ellipsoidal shape during resting, elongated along the [100] direction with almost no dimensional change along [0 (1) over bar 1]. Two orthogonal sectioning planes were selected for characterization using Orientation Imaging Microscopy (OIM): one in the plane containing [100] and [011] (longitudinal) and the other in the plane containing [0 (1) over bar 1] and [011] (transverse). OIM revealed patterns of alternating crystal rotations that develop as a function of strain and exhibit evolving length scales. The spacing and magnitude of these alternating misorientations increase in number density and decrease in spacing with increasing strain. C1 Univ Calif Lawrence Livermore Natl Lab, Div Mat Sci & Technol, Livermore, CA 94550 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. RP Schwartz, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Div Mat Sci & Technol, POB 5508, Livermore, CA 94550 USA. RI Campbell, Geoffrey/F-7681-2010 NR 9 TC 8 Z9 8 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 178 EP 181 DI 10.1115/1.2812364 PG 4 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100012 ER PT J AU Funsten, HO Gosling, JT Riley, P St Cyr, OC Forsyth, RJ Howard, RA Schwenn, R AF Funsten, HO Gosling, JT Riley, P St Cyr, OC Forsyth, RJ Howard, RA Schwenn, R TI Combined Ulysses solar wind and SOHO coronal observations of several west limb coronal mass ejections SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC CLOUDS; INTER-PLANETARY SHOCK; SMM OBSERVATIONS; FIELD STRUCTURE; EVENTS; SPACECRAFT; SPEEDS; LASCO; FLOWS; FLUX AB From October 1996 to January 1997, Ulysses was situated roughly above the west limb of the Sun as observed from Earth at a heliocentric distance of about 4.6 AU and a latitude of about 25 degrees. This presents the first opportunity to compare Solar and Heliospheric Observatory (SOHO) limb observations of coronal mass ejections (CMEs) directly with their solar wind counterparts far from the Sun using the Ulysses data. During this interval, large eruptive events were observed above the west limb of the Sun by the Large Angle Spectrometric Coronagraph (LASCO) on SOHO on October 5, November 28, and December 21-25, 1996, Using the combined plasma and magnetic field data from Ulysses, the October 5 event was clearly identified by several distinguishing signatures as a CME. The November 28 event was also identified as a CME that trailed fast ambient solar wind, although it was identified only by an extended interval of counterstreaming suprathermal electrons. The December 21 event was apparently characterized by a B-day interval of nearly radial field and a plasma rarefaction. For the numerous eruptive events observed by the LASCO coronagraph during December 23-25, Ulysses showed no distinct, individual CMEs, perhaps because of intermingling of two or more of the eruptive events. By mapping the Ulysses observations back in time to the Sun assuming a constant flow speed, we have identified intervals of plasma that were accelerated or decelerated between the LASCO and Ulysses observations. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. Computat Phys Inc, USN, Res Lab, Washington, DC 20375 USA. Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. RP Funsten, HO (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Prince Consort Rd, London SW7 2BZ, England. EM hfunsten@lanl.gov; jgosling@lanl.gov; uk2@iris023.saic.com; cst@sdac.nascom.nasa.gov; rforsyth@ic.ac.uk; howard@cronus.nrl.navy.mil; schwenn@linax1.mpae.gwdg.de RI Funsten, Herbert/A-5702-2015 OI Funsten, Herbert/0000-0002-6817-1039 NR 39 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 6679 EP 6689 DI 10.1029/1998JA900088 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600001 ER PT J AU Issautier, K Meyer-Vernet, N Moncuquet, M Hoang, S McComas, DJ AF Issautier, K Meyer-Vernet, N Moncuquet, M Hoang, S McComas, DJ TI Quasi-thermal noise in a drifting plasma: Theory and application to solar wind diagnostic on Ulysses SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-TEMPERATURE; SPECTROSCOPY; RADIO; DISTRIBUTIONS; PARAMETERS; SPEED; WAVES; TORUS AB The present paper provides the basic principles and analytic expressions of the quasi-thermal noise spectroscopy extended to measure the plasma bulk speed, as a tool for in situ space plasma diagnostics. This method is based on the analysis of the electrostatic field spectrum produced by the quasi-thermal fluctuations of the electrons and by the Doppler-shifted thermal fluctuations of the ions; it requires a sensitive radio receiver connected to an electric wire dipole antenna. Neglecting the plasma bulk speed, the technique has been routinely used in the low-speed solar wind, and it gives accurate measurements of the electron density and core temperature, in addition to estimates of parameters of the hot electron component. The present generalization of the method takes into account the plasma speed and thereby improves the thermal electron temperature diagnostic. The technique, which is relatively immune to spacecraft potential and photoelectron perturbations, is complementary to standard electrostatic analysers. Application to the radio receiver data from the Ulysses spacecraft yields an accurate plasma diagnostic. Comparisons of these results with those deduced from the particle analyser experiment on board Ulysses are presented and discussed. C1 Observ Paris, Dept Rech Spatiale, DESPA, CNRS URA 264, F-92195 Meudon, France. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Issautier, K (reprint author), Observ Paris, Dept Rech Spatiale, DESPA, CNRS URA 264, 5 Pl Jules Janssen, F-92195 Meudon, France. NR 26 TC 37 Z9 37 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 6691 EP 6704 DI 10.1029/1998JA900165 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600002 ER PT J AU Desai, MI Marsden, RG Sanderson, TR Lario, D Roelof, EC Simnett, GM Gosling, JT Balogh, A Forsyth, RJ AF Desai, MI Marsden, RG Sanderson, TR Lario, D Roelof, EC Simnett, GM Gosling, JT Balogh, A Forsyth, RJ TI Energy spectra of 50-keV to 20-MeV protons accelerated at corotating interaction regions at Ulysses SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ROTATING INTERACTION REGIONS; DIFFUSIVE SHOCK ACCELERATION; IONS OBSERVED UPSTREAM; SOLAR-WIND STREAM; SOUTH POLAR PASS; EARTHS BOW SHOCK; INTERPLANETARY SHOCKS; PARTICLE-ACCELERATION; SPATIAL VARIATION; ECLIPTIC-PLANE AB We analyze here the energy spectra of 50-keV to 20-MeV protons accelerated at corotating shocks observed at Ulysses in the southern heliosphere during 1992 and 1993. In general, our results are inconsistent with the predictions of two models based on diffusive shock acceleration theory (Fisk and Lee [1980] and Jones and Ellison [1991]). The main results are the following: (1) The relationships between the spectral indices and the shock compression ratio show significant departures from those predicted by the two models; the observed spectra are substantially harder than predicted; (2) the spectral indices at the reverse shocks depend strongly on the heliographic latitude of Ulysses; the hardest spectra are associated with strong quasi-perpendicular shocks observed between 20 degrees S and 30 degrees S; (3) the spectral indices at the reverse shocks are anticorrelated with the upstream plasma velocity V-u' in the de Hoffman-Teller frame of the shock; and (4) the spectral indices at the forward shocks show no dependence on either the shock parameters or the heliographic latitude. The latitudinal dependence of the reverse shock spectra is probably related to the tilt (similar to 25 degrees) of the heliospheric current sheet with respect to the solar equatorial plane during 1992 and 1993. The negative correlation between the spectral indices at the reverse shocks and V-u' indicates that the gradient drift mechanism plays a crucial role in accelerating particles at corotating interaction regions (CIRs). The differences in our observations at the forward and reverse shocks may be due to the presence of a more energetic seed population and an enhancement in the level of magnetic field fluctuations upstream of the trailing edges of the CIRs. C1 Univ Maryland, Dept Phys, MI Desai Space Phys Grp, College Pk, MD 20742 USA. European Space Agcy, Estec, Dept Space Sci, NL-2200 AZ Noordwijk, Netherlands. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Birmingham, Sch Astrophys & Space Phys, Birmingham B15 2TT, W Midlands, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Space & Atmospher Phys Grp, London SW7 2BZ, England. RP Desai, MI (reprint author), Univ Maryland, Dept Phys, MI Desai Space Phys Grp, College Pk, MD 20742 USA. RI Lario, David/D-9318-2016 OI Lario, David/0000-0002-3176-8704 NR 61 TC 30 Z9 30 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 6705 EP 6719 DI 10.1029/1998JA900176 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600003 ER PT J AU Gary, SP AF Gary, SP TI Collisionless dissipation wavenumber: Linear theory SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SPEED SOLAR-WIND; ULYSSES OBSERVATIONS; ACCELERATION; ANISOTROPY; IONS AB The collisionless dissipation wavenumber k(d) of a plasma fluctuation may be defined as the minimum value of wavenumber at which damping becomes significant. Linear Vlasov theory is used to determine k(d) for both magnetosonic and Alfven fluctuations in a spatially homogeneous, collisionless plasma with Maxwellian velocity distributions. Alfven mode properties at maximum dissipation are independent of T-e/T-p, and the corresponding magnetosonic mode properties are weakly dependent on this temperature ratio, so theory predicts that the proton beta beta(p) is the primary parameter determining k(d). Theory yields k(d)c/w(p) = S-k/beta(p)(alpha k) where w(p) is the proton plasma frequency and S-k and alpha(k) are fitting parameters; for the Alfven mode alpha(k) similar or equal to 0.3, whereas for the magnetosonic mode alpha(k) similar or equal to 0.8. This implies that Alfven fluctuations are the more likely source of collisionless dissipation for long wavelength magnetic turbulence cascading to shorter wavelengths at beta(p)less than or similar to 1, and magnetosonic fluctuations are more likely to dissipate such turbulence at beta(p) greater than or similar to 1. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gary, SP (reprint author), Univ Calif Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. NR 12 TC 36 Z9 36 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 6759 EP 6762 DI 10.1029/1998JA900161 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600008 ER PT J AU Dors, EE Kletzing, CA AF Dors, EE Kletzing, CA TI Effects of suprathermal tails on auroral electrodynamics SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA SHEET ION; SPECTRAL CHARACTERISTICS; GEOMAGNETIC CONDITIONS; ELECTRON POPULATIONS; MODEL; DISTRIBUTIONS; PRECIPITATION; COLLOCATION; FIELD AB The auroral current density-voltage and energy flux density-voltage relationships are derived under the assumption that magnetospheric electrons above the auroral acceleration region are described by the kappa distribution function. To illustrate the effects of this boundary condition on auroral precipitation, a two-dimensional model of auroral electrodynamics similar to that of Lyons [1980] has been developed by imposing current continuity in a region of converging electric field in the auroral zone. The current carried by precipitating magnetospheric electrons inside auroral arcs connects to return current regions at the are edges via ionospheric Pedersen currents. A key feature is the ability to parameterize the magnetospheric boundary electron population as either a kappa or Maxwellian distribution. For equal density and temperature a kappa = 5 boundary condition yields a parallel potential drop similar to 5% larger and a precipitating energy flux structure similar to 5% wider than those of its Maxwellian counterpart. More significant differences emerge between these two distributions when the density is held constant but the spectral shape of the distributions are allowed to differ. The kappa distribution results predict up to double the peak auroral energy flux and as much as a 20-30% increase in the latitudinal width of the auroral energy flux as compared with the Maxwellian results. The width and intensity of the inverted V structures in the model results are found to be closely related to the level of thermal energy flux outside the inverted V. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. RP Dors, EE (reprint author), Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, POB 1663,Mail Stop D466, Los Alamos, NM 87545 USA. NR 20 TC 9 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 6783 EP 6796 DI 10.1029/1998JA900135 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600011 ER PT J AU Lessard, MR Hudson, MK Anderson, BJ Arnoldy, RL Luhr, H Reeves, GD Sato, N Weatherwax, AT AF Lessard, MR Hudson, MK Anderson, BJ Arnoldy, RL Luhr, H Reeves, GD Sato, N Weatherwax, AT TI Evidence for a global disturbance with monochromatic pulsations and energetic electron bunching SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SYNCHRONOUS ORBIT; WAVES; ATMOSPHERE; IONOSPHERE; EXTENT; ISEE-1 AB We present data from a number of ground stations and satellites that reveal an example of a previously unreported type of global event. The event is characterized by the occurrence of monochromatic pulsations of widely varying frequencies in different regions of local times and L shells, The pulsations appear to be modulated with a similar to 45 min periodicity, Simultaneously, energetic particle fluxes observed at geosynchronous orbit (with energies resulting in a drift period of similar to 45 min) appear to become phase bunched and the pulsations are observed to occur coincident with minima in the particle bunching. Corresponding data from GOES 5 show an increase in the compressional component of the magnetic field with this period. Data from South Pole Station show fluctuations in the east-west component of the magnetic field at half this period, along with a weak auroral signature and riometer absorptions. We conclude that the data show the existence of a global disturbance with a compressional magnetic field signature, and we suggest that this compression induces a radial electric field, based on Faraday's law. Phase bunching of energetic electrons (due to the induction electric field) and monochromatic pulsations are consequences of the global disturbance, although the mechanism responsible for exciting the pulsations is not clear. C1 Univ Calgary, Dept Phys & Astron, Space Res Inst, Calgary, AB T2M 1N4, Canada. Dartmouth Coll, Dept Phys & Astron, Wilder Lab 6127, Hanover, NH 03755 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Ctr Space Sci, Durham, NH 03824 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 21218 USA. Geoforschungszentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany. Univ Calif Los Alamos Natl Lab, NIS 2, Los Alamos, NM 87545 USA. Natl Inst Polar Res, Tokyo 173, Japan. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Lessard, MR (reprint author), Univ Calgary, Dept Phys & Astron, Space Res Inst, 2500 Univ Dr NW, Calgary, AB T2M 1N4, Canada. EM lessard@phys.ucalgary.ca RI Anderson, Brian/I-8615-2012; Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 25 TC 10 Z9 10 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 7011 EP 7023 DI 10.1029/1998JA900155 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600030 ER PT J AU Kamide, Y Baumjohann, W Daglis, IA Gonzalez, WD Grande, M Joselyn, JA McPherron, RL Phillips, JL Reeves, EGD Rostoker, G Sharma, AS Singer, HJ Tsurutani, BT Vasyliunas, VM AF Kamide, Y Baumjohann, W Daglis, IA Gonzalez, WD Grande, M Joselyn, JA McPherron, RL Phillips, JL Reeves, EGD Rostoker, G Sharma, AS Singer, HJ Tsurutani, BT Vasyliunas, VM TI Comment on "Current understanding of magnetic storms: Storm-substorm relationships," by Y. Kamide et al. Reply SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Natl Observ Athens, Inst Ionospher & Space Res, Penteli, Greece. Inst Pesquisas Espaciais, Sao Paulo, Brazil. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. NOAA, Space Environm Ctr, Boulder, CO USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Alberta, Dept Phys, Edmonton, AB, Canada. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. RP Kamide, Y (reprint author), Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. EM kamide@stelab.nagoya-u.ac.jp; bj@mpe-garching.mpg.de; daglis@creator.space.noa.gr; gonzalez@dge.inpe.br; M.Grande@rl.ac.uk; jjoselyn@sec.noaa.gov; rmcpherron@igpp.ucla.edu; JLPhilli@ems.jsc.gov; reeves@lanl.gov; rostoker@space.ualberta.ca; ssh@avl.umd.edu; hsinger@sec.noaa.gov; btsurutani@jplsp.jpl.nasa.gov; vasyliunas@linaxl.mpae.gwdg.de RI Baumjohann, Wolfgang/A-1012-2010; Daglis, Ioannis/L-6100-2013; Reeves, Geoffrey/E-8101-2011; Grande, Manuel/C-2242-2013 OI Baumjohann, Wolfgang/0000-0001-6271-0110; Daglis, Ioannis/0000-0002-0764-3442; Reeves, Geoffrey/0000-0002-7985-8098; Grande, Manuel/0000-0002-2233-2618 NR 5 TC 1 Z9 1 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1999 VL 104 IS A4 BP 7051 EP 7051 DI 10.1029/1999JA900020 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600035 ER PT J AU Jarnik, M Lichti, U Simon, M Steven, AC AF Jarnik, M Lichti, U Simon, M Steven, AC TI Perturbed assembly of the cornified cell envelope in cultured keratinocytes and papilloma SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract C1 NIAMS, LSB, NIH, Bethesda, MD USA. NCI, Cellular Carcinogenesis & Tumor Promot Lab, NIH, Bethesda, MD 20892 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 1999 VL 112 IS 4 MA 304 BP 573 EP 573 PG 1 WC Dermatology SC Dermatology GA 182JL UT WOS:000079495800328 ER PT J AU Sanders, PG Keske, JS Leong, KH Kornecki, G AF Sanders, PG Keske, JS Leong, KH Kornecki, G TI High power Nd : YAG end CO2 laser welding of magnesium SO JOURNAL OF LASER APPLICATIONS LA English DT Article DE laser welding; magnesium welding; AZ31B welding; weld monitoring AB The laser beam weldability of AZ31B magnesium alloy was examined with high power pulsed Nd:YAG and continuous wave (cw) CO2 lasers, The low solid absorptivity, liquid viscosity, and liquid surface tension of magnesium make it more difficult to weld than steel. Welding parameters necessary to obtain sound autogenous welds were determined for both pulsed Nd:YAG and cw CO2 lasers, The weldability of magnesium was significantly better with the Nd:YAG laser. This observation was attributed to the higher absorption of the Nd:YAG beam, which in turn reduced the threshold irradiance required for welding and produced a more stable weldpool. The signal from an infrared weld monitor was correlated with both the penetration depth and the quantity of black powder on the workpiece after welding. The fine black powder was shown to result from evaporation of magnesium and zinc. The Nd:YAG welds were only slightly softer than the base material and had very narrow heat-affected zones. (C) 1999 Laser Institute of America. [S1042-346X(99)00104-7]. C1 Argonne Natl Lab, Technol Dev Div, Argonne, IL 60439 USA. RP Sanders, PG (reprint author), Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. NR 14 TC 38 Z9 41 U1 1 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1042-346X J9 J LASER APPL JI J. Laser Appl. PD APR PY 1999 VL 11 IS 2 BP 96 EP 103 PG 8 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA 184WU UT WOS:000079637400007 ER PT J AU Chen, Q Rondinone, AJ Chakoumakos, BC Zhang, ZJ AF Chen, Q Rondinone, AJ Chakoumakos, BC Zhang, ZJ TI Synthesis of superparamagnetic MgFe2O4 nanoparticles by coprecipitation SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Conference on Scientific and Clinical Applications of Magnetic Carriers (SCAMC2) CY MAY 28-30, 1998 CL CLEVELAND, OHIO DE spinel ferrites; magnetic nanoparticles; superparamagnetic; neutron diffraction; Mossbauer spectroscopy ID MAGNETIC-PROPERTIES; PARTICLES; DEPENDENCE AB MgFe2O4 nanoparticles have been synthesized by coprecipitation method. Magnetic measurements in combination with neutron diffraction have determined the existence of a superparamagnetic state in this metal oxide system. The superparamagnetic relaxation of magnetization in these nanoparticles has been studied by using Mossbauer spectroscopy. The relaxation time has been correlated with the particle size and temperature and is consistent with Neel theory. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Zhang, ZJ (reprint author), Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. RI Rondinone, Adam/F-6489-2013; Chakoumakos, Bryan/A-5601-2016 OI Rondinone, Adam/0000-0003-0020-4612; Chakoumakos, Bryan/0000-0002-7870-6543 NR 16 TC 141 Z9 151 U1 4 U2 46 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD APR PY 1999 VL 194 IS 1-3 BP 1 EP 7 DI 10.1016/S0304-8853(98)00585-X PG 7 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 184RQ UT WOS:000079627300002 ER PT J AU Kaminski, MD Nunez, L AF Kaminski, MD Nunez, L TI Extractant-coated magnetic particles for cobalt and nickel recovery from acidic solution SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Conference on Scientific and Clinical Applications of Magnetic Carriers (SCAMC2) CY MAY 28-30, 1998 CL CLEVELAND, OHIO DE Cyanex 272; D2EHPA; phosphinic acid; phosphoric acid; metal recovery; cobalt; nickel; metal separation; separation processes; magnetic separation; magnetic particles ID ASSISTED CHEMICAL-SEPARATION AB Waste minimization and recycling practices can often constitute a significant fraction of industrial operating costs. Magnetically assisted chemical separation (MACS) is a simple, cost-effective process that utilizes micrometer-sized magnetic composite materials containing a sorbed layer of chelating or ion exchange material. This paper presents the use of MACS particles for recovering cobalt and nickel from acidic solution. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Kaminski, MD (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 11 TC 45 Z9 46 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD APR PY 1999 VL 194 IS 1-3 BP 31 EP 36 DI 10.1016/S0304-8853(98)00579-4 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 184RQ UT WOS:000079627300006 ER PT J AU Nunez, L Kaminski, MD AF Nunez, L Kaminski, MD TI Transuranic separation using organophosphorus extractants adsorbed onto superparamagnetic carriers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Conference on Scientific and Clinical Applications of Magnetic Carriers (SCAMC2) CY MAY 28-30, 1998 CL CLEVELAND, OHIO DE solvent extraction; ion exchange; synergism; transuranic separation ID ASSISTED CHEMICAL-SEPARATION; MICROPARTICLES AB Ferromagnetic carriers with an absorbed layer of organophosphorus extractants are being evaluated for application in the separation and the recovery of low concentrations of actinides from nuclear waste solutions. The extractant-absorbed particles were characterized by gamma and liquid scintillation counting, scanning electron microscopy, and other physical measurements. The application of the process to Department of Energy remediation efforts is discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Nunez, L (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 8 TC 35 Z9 36 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD APR PY 1999 VL 194 IS 1-3 BP 102 EP 107 DI 10.1016/S0304-8853(98)00571-X PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 184RQ UT WOS:000079627300016 ER PT J AU Weaver, VM Bissell, MJ AF Weaver, VM Bissell, MJ TI Functional culture models to study mechanisms governing apoptosis in normal and malignant mammary epithelial cells SO JOURNAL OF MAMMARY GLAND BIOLOGY AND NEOPLASIA LA English DT Article DE cell death; tissue architecture; tumor; basement membrane; mammary epithelial cell ID EXTRACELLULAR-MATRIX; BASEMENT-MEMBRANE; GENE-EXPRESSION; RECIPROCAL INTERACTIONS; 3-DIMENSIONAL CULTURE; SIGNAL-TRANSDUCTION; BREAST-CANCER; TUMOR-CELLS; DIFFERENTIATION; DEATH AB Mammary tissue homeostasis depends upon dynamic interactions between the epithelial cells, their microenvironment (including the basement membrane and the stroma), and the tissue architecture, which influence each other reciprocally to regulate growth, death and differentiation in the gland. To study how apoptosis is regulated in normal mammary cells, and to understand its role in breast tumor pathogenesis, we need model systems that recapitulate breast tissue architecture and microenvironment in culture. We have established culture models of primary and established nonmalignant mammary cell lines from both rodent and human, and defined procedures to study how cell and tissue architecture affect signaling by the basement membrane. We show that both a basement membrane and an organized tissue structure are required to achieve sustained mammary cell survival. These models could now be used to investigate how the basement membrane represses apoptosis in normal cells, and how breast cancers become death-resistant. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Weaver, VM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. FU NCI NIH HHS [R01 CA057621, CA57621, CA64786, R01 CA057621-07, R01 CA064786, R01 CA064786-05, R37 CA064786] NR 57 TC 50 Z9 51 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1083-3021 J9 J MAMMARY GLAND BIOL JI J. Mammary Gland Biol. Neoplasia PD APR PY 1999 VL 4 IS 2 BP 193 EP 201 DI 10.1023/A:1018781325716 PG 9 WC Oncology; Endocrinology & Metabolism; Physiology SC Oncology; Endocrinology & Metabolism; Physiology GA 213EE UT WOS:000081258900009 PM 10426398 ER PT J AU Kini, AM Parakka, JP Geiser, U Wang, HH Rivas, F DiNino, E Thomas, S Dudek, JD Williams, JM AF Kini, AM Parakka, JP Geiser, U Wang, HH Rivas, F DiNino, E Thomas, S Dudek, JD Williams, JM TI Tetraalkyl- and dialkyl-substituted BEDT-TTF derivatives and their cation-radical salts: synthesis, structure, and properties SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article ID ORGANIC CONDUCTORS; CRYSTAL-STRUCTURE; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE DERIVATIVES; ELECTRICAL-PROPERTIES; PI-DONOR; METALS; TETRATHIAFULVALENE; SUPERCONDUCTORS; OXIDATION; VINYLOGUE AB Tetraalkyl and dialkyl derivatives, where alkyl = ethyl and propyl, of the organic electron donor molecule bis(ethylenedithio) tetrathiafulvalene, BEDT-TTF or ETT have been synthesized via the Diels-Alder approach. Several cation-radical salts of these new donors have been prepared and structurally characterized, and found to contain donor molecules in nominally higher oxidation states (+1, +1.5 and +2) than the typically observed oxidation state of +0.5 in BEDT-TTF sails. The higher solubility of the tetraalkyl and dialkyl derivatives in solvents used for crystal growth is proposed as the principal reason for this finding. Surprisingly, X-ray crystallographic studies reveal that the alkyl groups in the neutral tetraethyl-ET as well as the oxidized tetraethyl-ET and diethyl-ET molecules in their cation-radical salts adopt axial configurations: rather than the expected equatorial configurations. Electrical properties of the cation-radical sails have been found to be either insulating or semiconducting, consistent with the higher oxidation states of the donor molecules in the salts and the crystal structures. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Kini, AM (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Kini, Aravinda/F-4467-2012; OI Thomas, Seddon/0000-0003-0075-0744 NR 33 TC 21 Z9 21 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD APR PY 1999 VL 9 IS 4 BP 883 EP 892 DI 10.1039/a809132c PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 187PP UT WOS:000079795800008 ER PT J AU Zhang, XF Kung, HH Foltyn, SR Jia, QX Peterson, EJ Peterson, DE AF Zhang, XF Kung, HH Foltyn, SR Jia, QX Peterson, EJ Peterson, DE TI Speeding up film deposition rate: Its effects on microstructures of YBa2Cu3Oy superconducting thick films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID YTTRIA-STABILIZED-ZIRCONIA; BEAM-ASSISTED DEPOSITION; CRITICAL CURRENTS; BUFFER LAYERS; BICRYSTALS; WIRES AB Two very different pulsed laser deposition rates, 192 and 6 Angstrom/s, were used to produce 1 mu m thick superconducting YBa2Cu3Ox (YBCO) films on (001) SrTiO3 single-crystal substrates at 790 degrees C. Transmission electron microscopy (TEM) was used to characterize and compare microstructures between the two films. It has been found that the high deposition rate led to a slight deviation from the expected epitaxial orientations, and extra stress was induced in the films by increased lattice mismatch between the films and the substrates. In addition, misoriented YBCO grains were formed in the high-rate films after a thickness of about 150 nm. Postannealing in oxygen had no visible influence on these defects, although superconducting properties were improved significantly. In contrast to the high-rate films, overall epitaxial orientations have been formed in the low-rate films, and no misoriented YBCO grains were found. However, variations in lattice parameters and columnar voids were observed, although their existence apparently does not have considerable influence on superconducting current density (J(c)). Cation disorder was observed in both films. A two-step film growth mechanism is concluded which is responsible for the formation of some defects in the high-deposition rate films. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Zhang, XF (reprint author), Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Jia, Q. X./C-5194-2008 NR 21 TC 11 Z9 11 U1 1 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1999 VL 14 IS 4 BP 1204 EP 1211 DI 10.1557/JMR.1999.0164 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 235PC UT WOS:000082550400010 ER PT J AU Kerch, HM Long, GG Krueger, S Allen, AJ Gerhardt, R Cosandey, F AF Kerch, HM Long, GG Krueger, S Allen, AJ Gerhardt, R Cosandey, F TI Characterization of porosity over many length scales: Application to colloidal gels SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ANGLE NEUTRON-SCATTERING; X-RAY-SCATTERING; OF-STANDARDS; SILICA; GLASSES; MICROSCOPY AB Processing-microstructure relationships in a silica gel system, based on mixtures of colloidal sol and soluble potassium silicate, have been studied. Quantitative microstructural information regarding colloidal cluster sizes, size distributions, surface areas, and pore-size distribution from the nanopore range to the macropore range was determined via small-angle scattering and transmission electron microscopy. The colloid cluster size distribution varies systematically, with gels fabricated with the least colloidal fraction possessing the most polydisperse microstructure. It is shown that the porosity over the entire range can be tailored by selecting the appropriate starting chemistry; under the same pH conditions, the ratio of the two silicate ingredients controls the average size, the polydispersity of sizes, and the connectivity of the pores. A population of fine (2 nm) uniformly dispersed nanopores, which result from leaching, is responsible for large increases in surface area. The leaching process can be controlled by the surrounding macropore void size, which determines alkali transport. The product material consists of 85% large, open pores, with fine pores within the gel skeleton, making this gel an ideal candidate for controlled-porosity applications such as catalyst supports and magnetic composites. C1 US Dept Energy, Germantown, MD 20874 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. RP Kerch, HM (reprint author), US Dept Energy, Germantown, MD 20874 USA. RI Gerhardt, Rosario/D-6573-2012 OI Gerhardt, Rosario/0000-0001-8774-0842 NR 27 TC 4 Z9 4 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1999 VL 14 IS 4 BP 1444 EP 1454 DI 10.1557/JMR.1999.0195 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 235PC UT WOS:000082550400041 ER PT J AU Russell, AM Chumbley, LS Laabs, FC Russell, JD AF Russell, AM Chumbley, LS Laabs, FC Russell, JD TI A comparison of strengthening mechanisms in rolled and axisymmetrically deformed Ti-20Y composites SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID CU-NB ALLOYS; INTERPHASE BARRIER; INSITU COMPOSITES AB Two Ti-20%Y metal-metal composites were deformation processed: one axisymmetrically and the other by rolling. The microstructures, preferred crystallographic orientations, and tensile strengths of each were measured periodically as the deformation progressed. The axisymmetrically deformed Ti matrix developed a [10 (1) over bar 0] fiber texture, and the rolled composite acquired a texture with the [0001] tilted 31 degrees from the sheet normal toward the transverse direction with [10 (1) over bar 0] parallel to the rolling direction. The orientations of the {10 (1) over bar 10}[11 (2) over bar 0] and [0002][11 (2) over bar 0] slip systems in Ti with these textures were used in conjunction with the maximum possible slip distances for dislocation travel in each specimen to demonstrate that the axisymmetrically deformed material should be stronger than the rolled material for composites of equal phase thickness and spacing. The strengths of the two composites measured in this study were compared at similar microstructural phase sizes and spacings, and the axisymmetrically deformed composite was indeed found to be somewhat stronger, although the difference in strengths was not large. (C) 1999 Kluwer Academic Publishers. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Russell, AM (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. OI Russell, Alan/0000-0001-5264-0104 NR 33 TC 2 Z9 2 U1 0 U2 0 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 APR 1 PY 1999 VL 34 IS 7 BP 1447 EP 1460 DI 10.1023/A:1004542221169 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 190DJ UT WOS:000079946500003 ER PT J AU Zhu, Y Wu, L Tafto, J AF Zhu, Y Wu, L Tafto, J TI A study of charge distribution in Bi2Sr2CaCU2O8+delta superconductors using novel electron-diffraction and imaging techniques SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article; Proceedings Paper CT Frontiers of Electron Microscopy in Materials Science Conference CY APR 19-24, 1998 CL IRSEE, GERMANY SP Deutsch Forsch Gemeinsch, Max Planck Gesell, Argonne Natl Lab, Lawrence Livermore Natl Lab, UOP, Lawrence Berkeley Natl Lab, Los Alamos Natl Lab, Oak Ridge Natl Lab, Brookhaven Natl Lab DE electron diffraction and imaging of superconductors ID RAY-ABSORPTION SPECTROSCOPY; SINGLE-CRYSTAL; REFINEMENT; DENSITY; PARAMETERS; YBA2CU3O7 AB We report our study of the distribution of valence electrons in Bi2Sr2CaCu2O8+delta high-temperature superconductors using novel electron-diffraction and imaging techniques. The former method was based on quantitative analyses of the diffraction intensity of many reflections as a function of crystal thickness to determine, with an unprecedented accuracy, the Fourier components of the electron distribution in Bi2Sr2CaCu2O8+delta The latter was based on examining the effect of charge transfer on many-beam imaging by comparing the observed and calculated low- and high-resolution images of long-period displacive and charge modulation of the cuprate, Our study demonstrates that fast electrons hare greater sensitivity than X-raps to valence electrons distribution at small scattering angles, and that electron microscopy is a powerful tool in revealing charge distribution in materials. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Zhu, Y (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NR 22 TC 2 Z9 2 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD APR PY 1999 VL 194 BP 21 EP 29 PN 1 PG 9 WC Microscopy SC Microscopy GA 191UN UT WOS:000080040100004 ER PT J AU Furuya, K Ishikawa, N Allen, CW AF Furuya, K Ishikawa, N Allen, CW TI In-situ observation of shape and atomic structure of Xe nanocrystals embedded in aluminium SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article; Proceedings Paper CT Frontiers of Electron Microscopy in Materials Science Conference CY APR 19-24, 1998 CL IRSEE, GERMANY SP Deutsch Forsch Gemeinsch, Max Planck Gesell, Argonne Natl Lab, Lawrence Livermore Natl Lab, UOP, Lawrence Berkeley Natl Lab, Los Alamos Natl Lab, Oak Ridge Natl Lab, Brookhaven Natl Lab DE cuboctahedral crystal; high-resolution electron microscopy; off-axial; imaging technique; Xe nanocrystals ID RESOLUTION ELECTRON-MICROSCOPY; CU-FE ALLOY; IMPLANTED ALUMINUM; PB INCLUSIONS; AL; XENON; PRECIPITATION; KR AB An imaging technique to determine in situ the shape and atomic structure of nanosized Se crystals embedded in Al is described using high-resolution transmission electron microscopy (HRTEM). The Se nanocrystals, with sizes less than 5 nm were prepared by the implantation of 30 keV Xe+ into Al at room temperature. The fee Se nanocrystals are mesotactic with the Al lattice and have a lattice parameter approximate to 50% larger than that of Al. HRTEM images of the Se were not clear in [110] zone axis illumination because of the small number of Xe atoms relative to iii atoms in any atom column. An off-axial imaging technique that consists of tilting the specimen several degrees from a zone axis and defocusing to suppress the Al lattice fringes is employed for the 110 projection of the Xe/Al system and the structure of the Sc nanocrystals is successfully imaged. The Se images clearly represent projections of cuboctahedra with faces parallel to eight Al {111} planes truncated by six {100} planes. The results of multislice image simulations using a three-dimensional atomic model agreed well with the results obtained by the off-axial imaging technique. The usefulness of the technique is demonstrated with observations of crystal defects introduced into the Ne under intense 1000 keV electron irradiation. C1 Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. RP Furuya, K (reprint author), Natl Res Inst Met, 3-13 Sakura, Tsukuba, Ibaraki 305, Japan. NR 19 TC 17 Z9 17 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD APR PY 1999 VL 194 BP 152 EP 160 DI 10.1046/j.1365-2818.1999.00451.x PN 1 PG 9 WC Microscopy SC Microscopy GA 191UN UT WOS:000080040100016 ER PT J AU Johnson, JA Johnson, CE Holland, D Mekki, A Appleyard, P Thomas, MF AF Johnson, JA Johnson, CE Holland, D Mekki, A Appleyard, P Thomas, MF TI Transition metal ions in ternary sodium silicate glasses: a Mossbauer and neutron study SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID SCATTERING; DIFFRACTION; SOLIDS AB The structure of transition metal (TM) sodium silicate glasses of formulae (Fe2O3)(x)(Na2O)(0.3)(SiO2)(0.7-x) and (CoO)(x)(Na2O)(0.3)(SiO2)(0.7-x) where the nominal x=0, 0.05, 0.10, 0.15,0.15 and 0.20, have been studied using neutron diffraction and Mossbauer spectroscopy. The Mossbauer spectra of the iron-containing series show that both Fe3+ and Fe2+ are present, the majority being Fe3+, The isomer shifts show that the coordination number of Fe3+ is low, probably 4, and of Fe2+ somewhat higher though the measurement is less accurate. The neutron data show that both the iron and the cobalt are 4-coordinated with bond lengths of about 1.90 and 1.95 Angstrom, respectively with O-TM-O bond angles approaching 90 degrees. The Fe-O bond length decreases and the O-O bond length increases with increasing Fe2O3 content. The first sharp diffraction peak (FSDP) is split on addition of iron and cobalt, showing intermediate-range order (IRO) with a larger repeat distance. The effective Debye temperatures for Fe2+ and Fe3+ are 268 and 312 K, respectively, showing the different Fe-O bond strengths of the two oxidation states arising from their different charges. The shift in the Mossbauer spectra with temperature was not that expected from the second order Doppler shift and thermal expansion showing an intrinsic isomer shift dependence on temperature. An attempt was made to relate this to the possible changes in hybridization of the iron with the concentration of Fe2O3. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. Univ Warwick, Coventry CV4 7AL, W Midlands, England. Liverpool John Moores Univ, Liverpool L3 5UG, Merseyside, England. Univ Liverpool, Liverpool L69 3BX, Merseyside, England. RP Johnson, JA (reprint author), Argonne Natl Lab, Expt Facil Div, Bldg 360,9700 S Cass Ave, Argonne, IL 60439 USA. RI Johnson, Jacqueliine/G-7365-2011; Johnson, Jacqueline/P-4844-2014 OI Johnson, Jacqueline/0000-0003-0830-9275 NR 20 TC 32 Z9 32 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD APR PY 1999 VL 246 IS 1-2 BP 104 EP 114 DI 10.1016/S0022-3093(99)00069-1 PG 11 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 192JW UT WOS:000080076100013 ER PT J AU Olander, DR Mubayi, V AF Olander, DR Mubayi, V TI Review of the materials-chemistry models in the VICTORIA code SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID SEVERE ACCIDENT ANALYSES; LIGHT-WATER REACTORS; FISSION-PRODUCTS; TRANSPORT; OXIDATION AB Recently a Peer Review Committee established by the US Nuclear Regulatory Commission issued its report on VICTORIA, a detailed mechanistic computer code that addresses the release of fission products from degraded reactor fuel and the ex-core behavior of the released material. The present paper summarizes the findings of the report relevant to the materials-chemistry aspects of the code that apply chiefly to the high-temperature, steam-hydrogen environment of the degrading fuel and cladding. In addition to reviewing the theoretical foundation of the mechanisms used in the code, the assessment utilizes the 'test problem' technique. In this method, the code (or its methods) are applied to very simple fuel and cladding systems with variations of input conditions, code flags, and material properties. The output is judged against expected behavior for each change. The topics treated include the thermochemical database, the code's method of treating interphase equilibria, the model of fission product release, and the treatment of cladding oxidation and hydrogen production. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Olander, DR (reprint author), Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. NR 32 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 1 EP 10 DI 10.1016/S0022-3115(98)00737-5 PG 10 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100002 ER PT J AU Walters, LC AF Walters, LC TI Thirty years of fuels and materials information from EBR-II SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID BREEDER REACTOR-II; IRRADIATION; BEHAVIOR AB The Experimental Breeder Reactor-II (EBR-II) was a 62.5 MWt-20 MWe sodium cooled fast reactor that was operated successfully for 30 years. Over its period of operation a wealth of fuels and materials information originated from EBR-II. Several missions were conducted in EBR-II, all of which yielded new and valuable additions to the world's knowledge base for nuclear materials. Some of the first pioneering experiments on irradiation effects in stainless steels were conducted in EBR-II. Later, practical manifestations of enhanced irradiation creep, swelling, and loss of ductility were experienced on EBR-II components. In addition, for a period of more than 15 years, the EBR-II reactor would become the primary irradiation facility for all fast reactor fuels and materials research and development. Both the initial mission and final mission for EBR-II (the Integral Fast Reactor Concept, IFR), involved the remote reprocessing and irradiation of fast reactor metallic fuels. The fuels and materials information gleaned from these missions will be summarized with the intent of portraying a sample of the valuable legacy that EBR-II contributed to the world's store of nuclear fuels and materials knowledge. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Idaho Falls, ID 83403 USA. RP Walters, LC (reprint author), Argonne Natl Lab, POB 2528, Idaho Falls, ID 83403 USA. NR 33 TC 36 Z9 37 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 39 EP 48 DI 10.1016/S0022-3115(98)00760-0 PG 10 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100005 ER PT J AU Was, GS Allen, TR Busby, JT Gan, J Damcott, D Carter, D Atzmon, M Kenik, EA AF Was, GS Allen, TR Busby, JT Gan, J Damcott, D Carter, D Atzmon, M Kenik, EA TI Microchemistry and microstructure of proton-irradiated austenitic alloys: toward an understanding of irradiation effects in LWR core components SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID RADIATION-INDUCED SEGREGATION; CR-NI ALLOYS; GRAIN-BOUNDARY SEGREGATION; STRESS-CORROSION CRACKING; STAINLESS-STEEL; DEFORMATION MECHANISMS; MULTICOMPONENT ALLOYS; SELF-DIFFUSION; DEPENDENCE; TEMPERATURE AB Over 1200 measurements of grain boundary composition and microstructure have been made on 14 different austenitic Fe-Cr-Ni alloys following proton irradiation in the temperature range 200-600 degrees C and in the dose range 0.1-3.0 dpa. From these data, a greater understanding of radiation induced segregation (RIS) and microstructure development has been gained. Grain boundary composition measurements revealed that Cr depletes at grain boundaries, Ni enriches and Fe can either enrich or deplete depending on alloy composition. Analysis of temperature and composition dependence of RIS revealed that the magnitude and direction of grain boundary Segregation depends on alloy composition because the values of migration enthalpy of the alloy constituents are not the same, and diffusivities of the alloy constituents are composition-dependent. The dose dependence of segregation revealed ordering in Ni-base alloys and temperature dependence was used to show that RIS is consistent with a vacancy exchange mechanism. The dependence of segregation on composition is consistent with all known, relevant neutron data. RIS was found to be related to the development of the dislocation and void microstructures. Alloys in which the microstructure develops slower with dose also show slower changes in RIS. Similarly, it was shown that the dependence of swelling on composition is the same for neutron, ion and proton irradiation and all can be explained by the effect of RIS on defect diffusivity at the void nuclei. This paper illustrates the value of conducting carefully chosen irradiation experiments over several, well-controlled variables to elucidate the mechanisms underlying the microchemical and microstructural changes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Michigan, Coll Engn, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. RP Was, GS (reprint author), Univ Michigan, Coll Engn, Dept Nucl Engn & Radiol Sci, 1911 Cooley Bldg,2355 Bonisteel Blvd, Ann Arbor, MI 48109 USA. OI Allen, Todd/0000-0002-2372-7259 NR 57 TC 30 Z9 31 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 96 EP 114 DI 10.1016/S0022-3115(98)00897-6 PG 19 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100011 ER PT J AU Motta, AT Howe, LM Okamoto, PR AF Motta, AT Howe, LM Okamoto, PR TI Amorphization of Zr3Fe under electron irradiation SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID INTERMETALLIC COMPOUNDS; AMORPHOUS TRANSITION; ZIRCONIUM ALLOYS; CRYSTALLINE; KINETICS; SYSTEM; TRANSFORMATION; ZRCR2; ZRFE2; CUTI AB The intermetallic compound Zr3Fe has been made amorphous by 0.9 MeV electron irradiation. By performing this irradiation in situ, it was possible to conduct a systematic study of the influence of temperature, dose rate, electron energy and specimen orientation on the amorphization process. The critical temperature and the critical dose for amorphization were determined, and shown to depend on dose rate. By varying the electron energy, we determined the displacement energies for the Zr and Fe atoms in Zr3Fe, and showed that, at low electron energy, the amorphization rate is dependent on specimen orientation. We analyze these results in terms of a model based on amorphization occurring at a damage level where the modified free energy of the irradiated crystal exceeds the free energy of the amorphous phase. This model is shown to predict the amorphization kinetics, i.e. the critical temperature and critical dose for amorphization. We also compare amorphization induced by electron and ion irradiation. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Penn State Univ, Dept Nucl Engn, University Pk, PA 16802 USA. Atom Energy Canada Ltd, Fuel Channels Div, Chalk River Natl Labs, Chalk River, ON K0J 1J0, Canada. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Motta, AT (reprint author), Penn State Univ, Dept Nucl Engn, 231 Sackett Bldg, University Pk, PA 16802 USA. NR 55 TC 8 Z9 8 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 174 EP 186 DI 10.1016/S0022-3115(98)00657-6 PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100018 ER PT J AU Johnson, CE AF Johnson, CE TI Tritium behavior in lithium ceramics SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ELASTIC PROPERTIES; WATER-VAPOR; OXIDE; RELEASE; ADSORPTION; ALUMINATE; LI2O; TEMPERATURE; KINETICS; SYSTEM AB Tritium is the principal fuel for future fusion power reactors. Unfortunately, tritium is not available naturally and so must be produced through transmutation of lithium. The current approach to fusion reactor breeder blanket design is to place lithium-containing ceramics in a blanket module that surrounds the fusion plasma. These materials have performed well in numerous in-pile experiments, showing good thermal stability and good tritium release characteristics. Tritium release is particularly facile when an argon or helium purge gas containing hydrogen, typically at levels of about 0.1%, is used. However, the addition of hydrogen to the purge gas imposes a penalty when it comes to recovery of the tritium produced in the blanket. Optimizing tritium release while minimizing the amount of hydrogen necessary in the purge gas requires a detailed understanding of the tritium release process, especially the interactions of hydrogen with the surface of the lithium, ceramic. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Johnson, CE (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 63 TC 37 Z9 38 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 212 EP 220 DI 10.1016/S0022-3115(98)00905-2 PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100021 ER PT J AU Balooch, M Wang, WE LeMay, JD AF Balooch, M Wang, WE LeMay, JD TI Thermochemical properties of the hydrogen getter DEB SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Vapor pressures of the hydrogen getter 1,4 bis(phenylethynyl)benzene (DEB), together with two of its derivatives namely DEB mixed with carbon-supported Pd (DEB-Pd/C) and hydrogenated DEB-Pd/C, are measured from room temperature to the melting temperature (179 degrees C). The corresponding thermodynamic information, such as the enthalpy of vaporization, boiling point, and the deviation from ideal solution behavior of DEB-Pd/C, has been derived from the vapor pressure-temperature relationships. In addition, the hydrogenation kinetics of DEB-PdfC (powder form and rod-like) has also been investigated at a fixed pressure of 13.3 Pa (0.1 Torr) and at four temperatures, 21 degrees C, 35 degrees C, 45 degrees C and 55 degrees C. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Wang, WE (reprint author), Univ Calif Berkeley, Dept Nucl Engn, 4164 Etcheverry Hall, Berkeley, CA 94720 USA. NR 5 TC 7 Z9 9 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR 1 PY 1999 VL 270 IS 1-2 BP 248 EP 252 DI 10.1016/S0022-3115(98)00781-8 PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 192BV UT WOS:000080059100025 ER PT J AU Kim, KH Park, JM Kim, CK Hofman, GL Paik, KW AF Kim, KH Park, JM Kim, CK Hofman, GL Paik, KW TI Thermal compatibility studies of U3Si2 dispersion fuels prepared with centrifugally atomized powder SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The interaction between atomized U3Si2 and aluminum in dispersion fuel samples has been characterized and compared with that of comminuted U3Si2. Fuel samples with atomized powder showed a smaller volume increase compared to those with the comminuted powder, irrespective of heat treatment, and volume fraction of U3Si2 powder. The possible reasons for this seem to be as follows: (1) the smaller specific surface area of the atomized spherical powder compared to the irregular comminuted powder translating in a smaller U3Si2-Al interface area for the former affecting what appears to be a diffusion-controlled interaction process, (2) the atomized fuel samples also contain lower fraction of as-fabricated porosity than the comminuted fuel samples, which may enhance the restraint force in the swelling fuel meat, (3) the comminuted powder particles have distinctive aluminum penetration paths in the form of deformation zones that originated from the comminution process. There appear to be two pronounced penetration paths of aluminum into atomized U3Si2 powder; (1) through the phase interface, leaving a central unreacted island, (2) along grain boundaries, leaving several unreacted islands. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Korea Atom Energy Res Inst, Taejon 305353, South Korea. Argonne Natl Lab, Argonne, IL 60439 USA. Korea Adv Inst Sci & Technol, Taejon 30701, South Korea. RP Kim, KH (reprint author), Korea Atom Energy Res Inst, 150 Dukjin Dong, Taejon 305353, South Korea. NR 27 TC 6 Z9 6 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 1999 VL 270 IS 3 BP 315 EP 321 DI 10.1016/S0022-3115(99)00005-7 PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 197LK UT WOS:000080366100005 ER PT J AU Foster, JP Bunde, K Grossbeck, ML Gilbert, ER AF Foster, JP Bunde, K Grossbeck, ML Gilbert, ER TI Temperature dependence of the 20% cold worked 316 stainless steel steady state irradiation creep rate SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The irradiation creep data from four completed tests have been analysed to show that the steady state irradiation creep rate exhibits a moderate and complex temperature dependence, The irradiation creep tests were performed in the Experimental Breeder Reactor Number II (EBR-II) using beams and pressurized tubes, and in the Oak Ridge Reactor (ORR) and the High Flux Isotope Reactor (HFIR) using pressurized tubes. The data cover the temperature range from 200 degrees C to 585 degrees C, and show that from 200 degrees C to 330 degrees C, the steady state rate increases moderately with increasing temperature. At about 330 degrees C, the steady state rate peaks and rapidly decreases with increasing temperature from 330 degrees C to 370 degrees C. From 370 degrees C to 585 degrees C the steady state rate moderately increases with increasing temperature. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Westinghouse Elect Comp, Commercial Nucl Fuel Div, Columbia, SC 29250 USA. Argonne Natl Lab, Idaho Falls, ID USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. Pacific NW Lab, Richland, WA 99352 USA. RP Foster, JP (reprint author), Westinghouse Elect Comp, Commercial Nucl Fuel Div, 5801 Bluff Rd,PO Drawer R, Columbia, SC 29250 USA. NR 12 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 1999 VL 270 IS 3 BP 357 EP 367 DI 10.1016/S0022-3115(98)00748-X PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 197LK UT WOS:000080366100010 ER PT J AU Thomas, SR Stabin, MG Chen, CT Samaratunga, RC AF Thomas, SR Stabin, MG Chen, CT Samaratunga, RC TI MIRD Pamphlet No. 14 revised: A dynamic urinary bladder model for radiation dose calculations SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE dosimetry; urinary bladder radiation absorbed dose; dynamic bladder; MIRD dose calculation ID 2-FLUORO-2-DEOXY-D-GLUCOSE; DOSIMETRY AB The constant-volume urinary bladder model in the standard MIRD Pamphlet No. 5 (Revised) phantom has recognized limitations. Various investigators have developed detailed models incorporating more physiologically realistic features, such as expanding bladder contents and residual volume, and variable urinary input rate, initial volume and first void time. We have reviewed these published models and have developed a new model for calculation of radiation absorbed dose to the urinary bladder wall incorporating these aspects. Methods: The model consists of a spherical source with variable volume to simulate the bladder contents and a wall represented by a spherical shell of constant volume. The wall thickness varies as the source expands or contracts. The model provides for variable urine entry rate (three different hydration states), initial bladder contents volume, residual volume and first void time. The voiding schedule includes an extended nighttime gap during which the urine entry rate is reduced to one-half the daytime rate. Results: Radiation-absorbed dose estimates have been calculated for the bladder wall surface (including photon and electron components) and at several depths in the wall (electron component) for 2-F-18-fluoro-2-deoxy-D-glucose, Tc-99m-diethylenetriaminepentaacetic acid (DTPA), Tc-99m-HEDP, Tc-99m-pertechnetate, Tc-99m-red blood cells (RBCs), Tc-99m-glucoheptonate, Tc-99m-mercaptoacetyliglicine chelator (MAG3), Tc-99m-methylene diphosphonate (MDP), Tc-99m-hexamethylpropylene amine oxime (HMPAO), Tc-99m-human serum albumin (HSA), Tc-99m-MIBI (rest and stress), I-123-/I-124-/I-131-OIH, I-123/I-131-Nal, I-125-iothalamate, In-111-DTPA and Sr-89-SrCl. Conclusion: The new model tends to give a higher radiation absorbed dose to the bladder wall surface than the previous models. Large initial bladder volumes and higher rates of urine flow into the bladder result in lower bladder wall dose. The optimal first voiding time is from 40 min to 3 hr postadministration, depending on radiopharmaceutical. The data as presented in tabular and graphic form for each compound provide guidance for establishing radiation absorbed dose reduction protocols. C1 Univ Cincinnati, Coll Med, Dept Radiol, Cincinnati, OH 45267 USA. Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA. Univ Chicago, Chicago, IL 60637 USA. RP Thomas, SR (reprint author), Univ Cincinnati, Coll Med, Dept Radiol, E560,Med Sci Bldg, Cincinnati, OH 45267 USA. RI Chen, Chin-Tu/K-3393-2014 NR 36 TC 34 Z9 35 U1 0 U2 0 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 USA SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD APR PY 1999 VL 40 IS 4 BP 102S EP 123S PG 22 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 182WU UT WOS:000079521800033 PM 10210232 ER PT J AU Butcher, RJ Clark, DL Gordon, JC Watkin, JG AF Butcher, RJ Clark, DL Gordon, JC Watkin, JG TI Synthesis and X-ray crystal structures of the samarium mono(pentamethylcyclopentadienyl) aryloxide complexes (eta-C5Me5)Sm(O-2,6-t-Bu2C6H3)(2)(THF) and [(eta-C5Me5)Sm(O-2,6-i-Pr2C6H3)(3)Li(THF)]. Differences in metathesis chemistry of 2,6-di-iso-propylphenoxide and 2,6-di-tert-butylphenoxide ligands SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE samarium; aryloxide; metathesis; pentamethylcyclopentadienyl ID HIGHLY REACTIVE ORGANOLANTHANIDES; THF = TETRAHYDROFURAN; ORGANOMETALLIC CHEMISTRY; ORGANOAMIDO-LANTHANOIDS; METALLORGANIC COMPOUNDS; EPSILON-CAPROLACTONE; MOLECULAR-STRUCTURE; AROMATIC RING; ALKOXIDES; YTTRIUM AB The reaction of SmCl3 with three equivalents of KO-2,6-t-Bu2C6H3 in THF produces the tris(aryloxide) complex Sm(OAr)(3),(THF) (Ar = 2,6-t-Bu2C6H3, 1). Complex 1 undergoes clean metathesis reaction with one equivalent of LiC5Me5 to form the mono(pentamethylcyclopentadienyl) aryloxide derivative (eta-C5Me5)Sm(OAr)(2)(THF) (2). In contrast, an analogous reaction of LiC5Me5 with the 2,6-di-iso-propylphenoxide complex Sm(OAr*)(3)(THF)(2)(Ar* = 2,6-i-Pr2C6H3, 3) leads to overall addition of the alkali metal reagent, and isolation of the lithium-containing 'ate' complex [(eta-C5Me5)Sm(OAr*)(mu-OAr*)(2)Li(THF)] (4). Compounds 2 and 4 have been subjected to single-crystal X-ray diffraction studies. Complex 2 features a three-legged piano-stool geometry, with Sm-O distances to the aryloxide ligands of 2.133(6) and 2.188(6) Angstrom, and a Sm-O(THF) distance of 2.435(7) Angstrom. Complex 4 also exhibits a three-legged piano-stool geometry, with two of the aryloxide oxygen atoms coordinated to a lithium metal center. A THF ligand completes the coordination sphere of the lithium. The Sm-O bond lengths to the lithium-coordinated aryloxide oxygens (2.250(6) and 2.247(5) Angstrom) are longer than the distance to the terminal aryloxide (Sm-O = 2.144(6) Angstrom). The Li-O distances range from 1.876(17) to 1.945(18) Angstrom. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, NMT DO, Los Alamos, NM 87545 USA. RP Watkin, JG (reprint author), Howard Univ, Dept Chem, Washington, DC 20059 USA. RI Clark, David/A-9729-2011 NR 63 TC 20 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD APR 1 PY 1999 VL 577 IS 2 BP 228 EP 237 DI 10.1016/S0022-328X(98)01046-8 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 184UU UT WOS:000079632800012 ER PT J AU Koretsky, GM Kerns, KP Nieman, GC Knickelbein, MB Riley, SJ AF Koretsky, GM Kerns, KP Nieman, GC Knickelbein, MB Riley, SJ TI Reactivity and photoionization studies of bimetallic cobalt-manganese clusters SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL CLUSTERS; SMALL NICKEL CLUSTERS; IONIZATION-POTENTIALS; ELECTRONIC-STRUCTURE; NIOBIUM CLUSTERS; THRESHOLD PHOTOIONIZATION; MOLECULAR NITROGEN; IRON CLUSTERS; ATOMS; DEUTERIUM AB The reactivity of selected ConMnm (8 less than or equal to m + n less than or equal to 23) clusters with N-2 and the vertical ionization potentials (IPs) of selected ConMnm (8 less than or equal to m + n less than or equal to 31) clusters have been measured. No obvious correlation is found between the reactivities and the IPs. Inferences about cluster structure may be made from the nitrogen uptake data. In particular, whereas pure cobalt clusters tend to adopt structures having bulk packing, incorporation of manganese atoms into the cluster shifts the relative energies of close-lying isomers to favor an icosahedral growth sequence. For many cluster sizes, the maximum number of nitrogen molecules adsorbed on a cluster at -80 degrees C is equal to the number of cobalt atoms on the surface of the cluster, thereby giving insight into the cluster structure and the locations of the individual cobalt and manganese atoms in these bimetallic species. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Monmouth Coll, Dept Chem, Monmouth, IL USA. RP Knickelbein, MB (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 33 TC 49 Z9 50 U1 0 U2 6 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 APR 1 PY 1999 VL 103 IS 13 BP 1997 EP 2006 DI 10.1021/jp9844157 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184KQ UT WOS:000079611700011 ER PT J AU Lin, ZJ Jaffe, JE Hess, AC AF Lin, ZJ Jaffe, JE Hess, AC TI Multicenter integration scheme for electronic structure calculations of periodic and nonperiodic polyatomic systems SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; ANALYTIC 2ND DERIVATIVES; BASIS-SETS; MOLECULES; QUADRATURE; ENERGY AB We present a numerical integration scheme designed to treat the type of multicenter integrals encountered in electronic structure calculations. By developing a notation that differentiates between those atomic centers where integrands have significant amplitudes and those where they do not, we find a way to decompose multicenter integrals (into sums over one-center integrals) such that the number of operations needed for a given matrix element does not increase with increasing system size. In addition, a new adaptive one-center grid is presented that accounts for the shell structures of core electrons while allowing for the vastly different behavior of integrands in the valence and tail regions. Through the use of model integrands the necessary grid points are automatically generated for a given system based on the accuracy requested. Our new multicenter decomposition scheme and one-center grid have been tested separately and in conjunction with each other. Results of such tests demonstrate that our decomposition scheme combined with our one-center grid provides significant improvements over existing multicenter integration schemes. In addition to demonstrating the efficiency of the method for any size system, we will show that the CPU cost of an integral remains constant for systems larger than some easily achievable threshold size. In general comparison shows that the larger the system, the higher is the percent gain in efficiency over previously published methods. In addition, the higher the accuracy targeted, the higher percentage the gain. Also, the higher the accuracy required for a given system, the higher is the gain ire efficiency. The method is therefore of great use for large polyatomic molecules and periodic systems. C1 Pacific NW Lab, Condensed Matter Theory Grp, Dept Mat Sci, Richland, WA 99352 USA. RP Pacific NW Lab, Condensed Matter Theory Grp, Dept Mat Sci, POB 999, Richland, WA 99352 USA. EM zijinglin@usa.net RI Lin, Zijing/D-4050-2009 NR 37 TC 17 Z9 17 U1 1 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 APR 1 PY 1999 VL 103 IS 13 BP 2117 EP 2127 DI 10.1021/jp983668x PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184KQ UT WOS:000079611700025 ER PT J AU Pieper, J Voigt, J Small, GJ AF Pieper, J Voigt, J Small, GJ TI Chlorophyll a Franck-Condon factors and excitation energy transfer SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID HARVESTING COMPLEX-II; ANTENNA COMPLEX; SPECTROSCOPY; TEMPERATURE; ABSORPTION; DYNAMICS; SPECTRA AB The Franck-Condon factors for the S-1(Q(y),)<----> S-o electronic transition of chlorophyll (Chl) molecules are important for understanding excitation energy transfer in photosynthetic complexes. Currently, there are two sets of Chi a Franck-Condon factors for over 40 modes, one determined by spectral hole burning and the other by fluorescence line narrowing. Those obtained by the latter spectroscopy are, on average, a factor of 30 times smaller than the hole burning values. Nonline-narrowed fluorescence results for the light-harvesting complex II of photosystem Il at 4.2 K are presented that agree quite well with the hole burning but not the fluorescence line narrowing values. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Humboldt Univ, Inst Phys, D-10099 Berlin, Germany. RP Small, GJ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 24 TC 32 Z9 33 U1 0 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 APR 1 PY 1999 VL 103 IS 13 BP 2319 EP 2322 DI 10.1021/jp984460e PG 4 WC Chemistry, Physical SC Chemistry GA 184KU UT WOS:000079612000001 ER PT J AU Scholes, GD Gould, IR Cogdell, RJ Fleming, GR AF Scholes, GD Gould, IR Cogdell, RJ Fleming, GR TI Ab initio molecular orbital calculations of electronic couplings in the LH2 bacterial light-harvesting complex of Rps-acidophila SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Review ID PHOTOSYNTHETIC ANTENNA COMPLEXES; CHEMICALLY SYNTHESIZED POLYPEPTIDES; EXCITON RESONANCE INTERACTIONS; PIGMENT-PROTEIN COMPLEXES; ENERGY-TRANSFER; RHODOBACTER-SPHAEROIDES; PURPLE BACTERIA; RHODOPSEUDOMONAS-ACIDOPHILA; EXCITATION TRANSFER; RHODOSPIRILLUM-RUBRUM AB The results of ab initio molecular orbital calculations of excited states and electronic couplings (for energy transfer) between the B800 and B850 bacteriochlorophyll a (Bchl) chromophores in the peripheral light-harvesting complex (LH2) of the purple photosynthetic bacterium Rhodopseudomonas acidophila are reported. Electronic couplings are estimated from "supermolecule" calculations of Bchl dimers using the CI-singles methodology and 3-21G" or 6-31G" basis sets. A scheme for dissecting the coupling into contributions from the Coulombic coupling and the short-range coupling (i.e., dependent on interchromophore orbital overlap) is reported. B850 couplings are calculated to be [total (Coulombic + short)]: intrapolypeptide dimer 320 (265 + 55) cm(-1) and interpolypeptide dimer 255 (195 + 60) cm(-1) at the CIS/6-31G* level. These results differ significantly from those estimated using the point dipole approximation. The effect of including Mg ligands (His residues) and H-bonding residues (Trp and Tyr) is also investigated. The consequences for superradiance and energy transfer dynamics and mechanism are discussed. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Fleming, GR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 102 TC 136 Z9 143 U1 4 U2 27 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 APR 1 PY 1999 VL 103 IS 13 BP 2543 EP 2553 DI 10.1021/jp9839753 PG 11 WC Chemistry, Physical SC Chemistry GA 184KU UT WOS:000079612000029 ER PT J AU Barsoum, MW El-Raghy, T Rawn, CJ Porter, WD Wang, H Payzant, EA Hubbard, CR AF Barsoum, MW El-Raghy, T Rawn, CJ Porter, WD Wang, H Payzant, EA Hubbard, CR TI Thermal properties of Ti3SiC2 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE thermal conductivity; thermal expansion; high temperature neutron diffraction ID TEMPERATURE AB The thermal properties of polycrystalline Ti3SiC2 in the 25 degrees C-1000 degrees C temperature range determined by Rietveld refinement of high temperature neutron diffraction data, show that at all temperatures, the amplitudes of vibration of the Si atoms are higher than those of the Ti and C atoms. Up to 700 degrees C, the vibrations of the Si atoms are quite isotropic but the vibrations of the other atoms are greater along the c-than along the a-axis. The amplitudes of vibration of the Ti atoms adjacent to the Si atoms are higher and more anisotropic than for the other Ti atom sandwiched between the C-layers. Good agreement is obtained between the bulk thermal expansion coefficients measured by dilatometry, 9.1(+/-0.2) x 10(-6)degrees C-1, and the values from the neutron diffraction results, 8.9(+/-0.1) x 10(-6)degrees C-1. The thermal expansion coefficients along the a-and c-axes are, respectively, 8.6(+/-0.1) x 10(-6)degrees C-1 and 9.7(+/-0.1) x 10(-6)degrees C-1. The heat capacity is 110 J/mol K at ambient temperatures and extrapolates to approximate to 155 J/mol K at 1200 degrees C. The room temperature thermal conductivity is 37 W/m K and decreases linearly to 32 W/m K at 1200 degrees C. The thermal conductivity is dominated by delocalized electrons. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Barsoum, MW (reprint author), Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. EM barsoumw@post.drexel.edu RI Payzant, Edward/B-5449-2009; Wang, Hsin/A-1942-2013 OI Payzant, Edward/0000-0002-3447-2060; Wang, Hsin/0000-0003-2426-9867 NR 32 TC 208 Z9 221 U1 3 U2 39 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD APR PY 1999 VL 60 IS 4 BP 429 EP 439 DI 10.1016/S0022-3697(98)00313-8 PG 11 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 181UX UT WOS:000079461800001 ER PT J AU Ginocchio, JN AF Ginocchio, JN TI On the relativistic origins of pseudo-spin symmetry in nuclei SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID STATES AB We show that pseudo-spin symmetry originates from an SU(2) symmetry of the Dirac Hamiitonian. Furthermore, we demonstrate that pseudo-spin symmetry is approximately conserved for a Dirac Hamiltonian with realistic scalar and vector potentials. We discuss pseudo-SU(3) symmetry in this context as well. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ginocchio, JN (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 26 TC 16 Z9 16 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 617 EP 622 DI 10.1088/0954-3899/25/4/008 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800008 ER PT J AU Vincent, SM Regan, PH Blumenthal, D Carpenter, M Davids, CN Gelletly, W Janssens, RVF Lister, CJ Seweryniak, D Schwartz, J Simpson, J Warner, DD AF Vincent, SM Regan, PH Blumenthal, D Carpenter, M Davids, CN Gelletly, W Janssens, RVF Lister, CJ Seweryniak, D Schwartz, J Simpson, J Warner, DD TI Discrete line spectroscopy of Ga-62(31) with AYEBALL SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID HIGH-SPIN STATES; N=Z NUCLEI; T=0 AB The excited states of the seif-conjugate, odd-odd system, Ga-62(31) have been investigated following the fusion-evaporation reaction Ca-40(Mg-24, pn) Ga-62 at a beam energy of 65 MeV. Identification of candidate transitions in this nucleus were made using the AYEBALL gamma-ray array following the selection of the recoil products with the Argonne fragment mass analyser (FMA) and a split anode ionization chamber. Spin assignments have been made on the basis of measured directional correlations from oriented states (DCO ratios). The resulting level scheme is presented and candidates for T = 1 and T = 0 structures suggested. C1 Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. CCLRC Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RP Vincent, SM (reprint author), Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 15 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 679 EP 683 DI 10.1088/0954-3899/25/4/019 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800019 ER PT J AU Clark, RM AF Clark, RM TI The 'magnetic rotation' of nuclei SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID SHEARS MECHANISM; BANDS; LIFETIMES; PB-198 AB Lifetimes of states in Irotational-like' M1 bands known in the A similar to 200 and A similar to 110 regions have been determined through a series of experiments performed with the Gammasphere array. The deduced B(M1) values display a characteristic decrease with increasing angular momentum. This is a clear signature of the 'shears' mechanism in which the states in the band are formed from the recoupling of valence proton and neutron spin vectors, j(pi) and j(nu). The rotational-like behaviour of the bands can be interpreted in terms of an effective interaction between j(pi) and j(nu). It has been suggested that the structures are examples of a novel mode of nuclear excitation-'magnetic rotation'. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Clark, RM (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 13 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 695 EP 698 DI 10.1088/0954-3899/25/4/022 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800022 ER PT J AU Longour, C Narro, JG Blank, B Lewitowicz, M Miehe, C Regan, PH Applebe, D Axelsson, L Bruce, AM Catford, WN Chandler, C Clark, RM Cullen, DM Czajkowski, S Daugas, JM Dessagne, P Fleury, A Frankland, L Gelletly, W Giovinazzo, J Greenhalgh, B Grzywacz, R Harder, M Jones, KL Kelsall, N Kszczot, T Page, RD Pearson, CJ Reed, AT Sorlin, O Wadsworth, R AF Longour, C Narro, JG Blank, B Lewitowicz, M Miehe, C Regan, PH Applebe, D Axelsson, L Bruce, AM Catford, WN Chandler, C Clark, RM Cullen, DM Czajkowski, S Daugas, JM Dessagne, P Fleury, A Frankland, L Gelletly, W Giovinazzo, J Greenhalgh, B Grzywacz, R Harder, M Jones, KL Kelsall, N Kszczot, T Page, RD Pearson, CJ Reed, AT Sorlin, O Wadsworth, R TI Half-lives of the odd-odd N=Z nuclei Y-78, Nb-82, Tc-86 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID FRAGMENTATION; DECAY AB The heavy odd-odd N = Z nuclei Rb-74, Y-78, Nb-82 Tc-86 have been produced at GANIL by fragmentation of a 60 MeV/u Mo-92 beam on a natural nickel target. The species of interest were selected and identified by their energy loss in a silicon detector and their time of flight through the LISE spectrometer. The ions were implanted in a silicon strip detector in which their beta-decay was observed. The measured half-lives for Y-78, Nb-82, Tc-86 correspond to superallowed transitions and may sign Fermi transitions on the basis of log ft values. Our experimental results pave the way for further and more precise measurements of these nuclei. C1 IN2P3, IReS Strasbourg, UMR 7500, F-67037 Strasbourg 2, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. CEN Bordeaux Gradignan, F-33175 Gradignan, France. GANIL, F-14021 Caen, France. Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden. Univ Brighton, Dept Mech Engn, Brighton BN2 4GJ, E Sussex, England. Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ York, Dept Phys, York YO1 4DD, N Yorkshire, England. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Inst Phys Nucl, F-91406 Orsay, France. RP Longour, C (reprint author), IN2P3, IReS Strasbourg, UMR 7500, BP28, F-67037 Strasbourg 2, France. RI Jones, Katherine/B-8487-2011; harder, marie/D-3157-2013; OI Jones, Katherine/0000-0001-7335-1379; harder, marie/0000-0002-1811-4597; Bruce, Alison/0000-0003-2871-0517 NR 12 TC 4 Z9 4 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 759 EP 762 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800030 ER PT J AU Schuck, C Gueorguieva, E Stephens, FS Deleplanque, MA Hannachi, F Korichi, A Lopez-Martens, A Kharraja, B Kelly, WH Vieu, C Kaci, M Dionisio, JS Deloncle, I Gall, BJP van Severen, UJ Pohler, W Schulze, B Hubel, H Wadsworth, R AF Schuck, C Gueorguieva, E Stephens, FS Deleplanque, MA Hannachi, F Korichi, A Lopez-Martens, A Kharraja, B Kelly, WH Vieu, C Kaci, M Dionisio, JS Deloncle, I Gall, BJP van Severen, UJ Pohler, W Schulze, B Hubel, H Wadsworth, R TI Pseudo-spin symmetry and identical SD bands: the excited superdeformed bands in Au-191 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID ALIGNMENT; PARITY AB Two excited superdeformed bands observed in Au-191. which have an identical energy relationship with the even-even Hg-192 core, are suggested to be two members of the pseudo-spin doublet [431]1/2, 3/2. C1 IN2P3, CSNSM, CNRS, F-91405 Orsay, France. Univ Sofia, Fac Phys, BU-1126 Sofia, Bulgaria. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. IReS Strasbourg, F-67037 Strasbourg, France. Iowa State Univ, Ames, IA 50011 USA. Univ Bonn, Inst Strahlen & Kernphys, D-53115 Bonn, Germany. Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. RP Schuck, C (reprint author), IN2P3, CSNSM, CNRS, F-91405 Orsay, France. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 807 EP 809 DI 10.1088/0954-3899/25/4/042 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800042 ER PT J AU Zhang, JY Sun, Y Riedinger, LL Guidry, M AF Zhang, JY Sun, Y Riedinger, LL Guidry, M TI Does an independent quasiparticle picture hold in mass-190 superdeformed nuclei? SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID BANDS AB We investigate the independent quasiparticle (QP) picture for superdeformed nuclei of the mass-190 region, which is expected to lead to additivity in certain physical quantities. Obvious deviations from additivity are found from both projected shell model calculations and experimental data. The cause of the deviation can be decomposed and identified through this model. Our study suggests that the independent QP picture may not be fully appropriate for this mass region. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Zhang, JY (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RI Sun, Yang/P-2417-2015 NR 3 TC 1 Z9 1 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 819 EP 821 DI 10.1088/0954-3899/25/4/045 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800045 ER PT J AU Garrett, PE Lehmann, H Jolie, J McGrath, CA Yeh, MF Yates, SW AF Garrett, PE Lehmann, H Jolie, J McGrath, CA Yeh, MF Yates, SW TI Quadrupole-octupole coupled states in Cd-112 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID 2-PHONON CHARACTER; MULTIPHONON STATES; EXCITATION; ND-142; MODEL AB Negative-parity excitations in the 2.5 MeV region in Cd-112 have been investigated with the (n, n'gamma) reaction. Several of these states exhibit enhanced B(E2) values for decay to the 3(1)(-) octupole state, indicative of quadrupole-octupole coupled (2(+) x 3(-)) structures. The B(E1) values observed are typically in the range of 1-5 x 10(-4) W.u., irrespective of the final state. C1 Univ Kentucky, Lexington, KY 40506 USA. Univ Fribourg, Inst Phys, CH-1700 Fribourg, Switzerland. RP Garrett, PE (reprint author), Lawrence Livermore Natl Lab, L-414,POB 808, Livermore, CA 94550 USA. RI McGrath, Christopher/E-8995-2013 NR 16 TC 1 Z9 1 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 823 EP 825 DI 10.1088/0954-3899/25/4/046 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800046 ER PT J AU Amzal, N Cocks, JFC Butler, PA Cann, KJ Greenlees, PT Jones, GD Asztalos, S Clark, RM Deleplanque, MA Diamond, RM Fallon, P Lees, IY Machiavelli, AO MacLeod, RW Stephens, FS Jones, PM Julin, R Broda, R Fornal, B Smith, JF Lauritsen, T Bhattacharyya, P Zhang, CT AF Amzal, N Cocks, JFC Butler, PA Cann, KJ Greenlees, PT Jones, GD Asztalos, S Clark, RM Deleplanque, MA Diamond, RM Fallon, P Lees, IY Machiavelli, AO MacLeod, RW Stephens, FS Jones, PM Julin, R Broda, R Fornal, B Smith, JF Lauritsen, T Bhattacharyya, P Zhang, CT TI Spectroscopic study of Th228-234 nuclei using multi-nucleon transfer reactions SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton AB Light-actinide nuclei in the octupole deformed region have been populated using multi-nucleon transfer from Th-232. The energy level schemes of several thorium isotopes with A = 228-234 have been extended up to I similar to 24 (h) over bar and negative parity states have been observed for the first time in Th-234. A systematic study of the difference in alignment between the positive- and negative-parity bands in thorium nuclei in this mass region shows that Th-228,Th-230,Th-234 behave like octupole vibrators, in contrast with Th-224,Th-226, which are octupole-deformed in character. An intrinsic electric dipole moment has been measured for the first time in Th-234. The small value obtained is consistent with the vibrational description of this nucleus. C1 Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. H Niewodniczanski Inst Nucl Phys, PL-31342 Krakow, Poland. SUNY Stony Brook, Stony Brook, NY 11794 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RP Amzal, N (reprint author), Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. OI Butler, Peter/0000-0001-6080-9205 NR 6 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 831 EP 834 DI 10.1088/0954-3899/25/4/048 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800048 ER PT J AU Andreyev, AN Bijnens, N Huyse, M Van Duppen, P Leino, M Enqvist, T Kuusiniemi, P Trzaska, W Uusitalo, J Fotiades, N Cizewski, JA McNabb, DP Ding, KY Davids, CN Janssens, RVF Seweryniak, D Carpenter, MP Amro, H Decrock, P Reiter, P Nisius, D Brown, LT Fischer, S Lauritsen, T Wauters, J Bingham, CR Conticchio, LF AF Andreyev, AN Bijnens, N Huyse, M Van Duppen, P Leino, M Enqvist, T Kuusiniemi, P Trzaska, W Uusitalo, J Fotiades, N Cizewski, JA McNabb, DP Ding, KY Davids, CN Janssens, RVF Seweryniak, D Carpenter, MP Amro, H Decrock, P Reiter, P Nisius, D Brown, LT Fischer, S Lauritsen, T Wauters, J Bingham, CR Conticchio, LF TI alpha-decay characteristics of neutron-deficient Po-190,Po-192 nuclei and alpha branching ratios of Pb-186,Pb-188 isotopes SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID PO-190 AB By using complete fusion reactions S-32+ Er-164 and Ti-48+ Sm-144, leading to Po-196 and Po-192 compound nuclei, improved alpha-decay characteristics for neutron-deficient Po-190,Po-192 isotopes have been obtained. The experiments have been performed at the fragment mass analyzer (Argonne) and at the RITU gas-filled separator (Jyvaskyla). In Po-192 the l = 0 decay to the excited 0(+) state in Pb-188 is two times faster than the decay to the ground state. For Po-190 more precise values of the alpha-decay energy E-alpha = 7545(15) keV and half-life T-1/2 = 2.53(33) ms were measured. By using correlated alpha-decay chains alpha-branching ratios of 38(9)% and 9.3(8)% were experimentally deduced for the first time for Pb-186 and Pb-188, respectively. The reduced alpha-width systematics is extended for even Po isotopes, confirming a persistence of the saturation towards the lighter isotopes. Absence of any anomalies in the reduced alpha-widths for the neutron-deficient Pb isotopes is confirmed. C1 Univ Leuven, Inst Kern & Stralingsfys, B-3001 Louvain, Belgium. Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. Rutgers State Univ, Dept Phys & Astron, New Brunswick, NJ 08903 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Joint Inst Nucl Res, FLNP, Dubna 141980, Russia. RP Andreyev, AN (reprint author), Univ Leuven, Inst Kern & Stralingsfys, Celestijnenlaan 200D, B-3001 Louvain, Belgium. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 8 TC 30 Z9 30 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 835 EP 837 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800049 ER PT J AU Kondev, FG Riley, MA Brown, TB Clark, RM Devlin, M Fallon, P Hartley, DJ Hibbert, IM Joss, DT LaFosse, DR Laird, RW Lerma, F Lively, M Nolan, PJ O'Brien, NJ Paul, ES Pfohl, J Sarantites, DG Sheline, RK Shepherd, SL Simpson, J Wadsworth, R AF Kondev, FG Riley, MA Brown, TB Clark, RM Devlin, M Fallon, P Hartley, DJ Hibbert, IM Joss, DT LaFosse, DR Laird, RW Lerma, F Lively, M Nolan, PJ O'Brien, NJ Paul, ES Pfohl, J Sarantites, DG Sheline, RK Shepherd, SL Simpson, J Wadsworth, R TI Relative quadrupole deformations for structures in odd proton (Z=59) Pr nuclei near mass similar to 130 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID DEFORMED ROTATIONAL BANDS; LIFETIME MEASUREMENTS; PR-130 AB The quadrupole moments for collective structures in the odd proton (Z = 59) Pr-130, Pr-131 and Pr-132 nuclei have been measured using the Doppler-shift attenuation method. New information is presented on the shape-driving behaviour of the 9/2(+)[404] (g(9/2)) proton and 1/2(-)[541] (f(7/2), h(9/2)) neutron Nilsson configurations. While the involvement of the former orbital leads to quadrupole deformations that are comparable to those observed for the so-called superdeformed bands in this mass region, the beta(2) values for structures that include the 1/2(-)[541] neutron are found to lie intermediate between those observed for normally deformed and superdeformed bands. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Daresbury Lab, CLRC, Warrington WA4 4AD, Cheshire, England. RP Kondev, FG (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RI Devlin, Matthew/B-5089-2013 OI Devlin, Matthew/0000-0002-6948-2154 NR 10 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 893 EP 895 DI 10.1088/0954-3899/25/4/063 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800063 ER PT J AU Kondev, FG Riley, MA Simpson, J Janssens, RVF Afanasjev, AV Ragnarsson, I Brown, TB Hartley, DJ Carpenter, MP Fallon, P Fischer, SM Khoo, TL Lauritsen, T Ma, WC Sharpey-Schafer, JF Lisle, JC Kalfas, CA AF Kondev, FG Riley, MA Simpson, J Janssens, RVF Afanasjev, AV Ragnarsson, I Brown, TB Hartley, DJ Carpenter, MP Fallon, P Fischer, SM Khoo, TL Lauritsen, T Ma, WC Sharpey-Schafer, JF Lisle, JC Kalfas, CA TI Exploring the I=50-60h domain: collective and terminating structures in Dy-156, Er-159 and Er-160. SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID HIGH-SPIN; BANDS; 50H AB Very high spin (50-60 (h) over bar) states in transitional Dy-156, Er-159 and Er-160 nuclei have been studied using the GAMMASPHERE and EUROGAM gamma-ray spectrometers. The lowest energy positive-parity bands in Dy-156 are found to evolve smoothly towards an oblate shape in contrast to the sudden change observed in the neighbouring Er-158 nucleus. In Er-159, the decay path of the positive-parity yrast band splits above I-pi = 85/2(+) and favoured multi-particle-hole states are identified in the irregular pattern at 89/2(+) and 101/2(+). The yrast structure of Er-160 is found to remain collective up to and beyond 50 (h) over bar with no sign of an apparent termination. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Lund Inst Technol, Dept Math Phys, Lund, Sweden. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Natl Accelerator Ctr, ZA-7131 Faure, South Africa. Univ Manchester, Schuster Lab, Manchester M13 9PL, Lancs, England. NCSR Demokritos, Inst Nucl Phys, GR-15310 Athens, Greece. RP Kondev, FG (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 10 TC 12 Z9 12 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 897 EP 899 DI 10.1088/0954-3899/25/4/064 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800064 ER PT J AU Raman, S Kahane, S Bhatt, KH AF Raman, S Kahane, S Bhatt, KH TI Quadrupole collectivity of angular-momentum projected states of nucleons in the high-j intruder single-particle states SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton AB Ever since the pioneering work of Elliott (Elliott J P 1958 Proc. R. Sec. London Series A 245 128, 562), quadrupole collectivity in deformed nuclei has been economically described in terms of SU3 symmetry. Microscopic SU3 symmetry is not present in the deformed intrinsic states of n nucleons in the abnormal-parity single-particle states j(a). However, such (j(a))(n) stares do possess some SU3-symmetry-like properties as shown in this work. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Natl Res Ctr, Beer Sheva, Israel. Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. RP Raman, S (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 905 EP 907 DI 10.1088/0954-3899/25/4/066 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800066 ER PT J AU Mohammadi, S Regan, PH Vincent, SM Blumenthal, D Carpenter, M Davids, CN Gelletly, W Janssens, RVF Lister, CJ Pearson, CJ Simpson, J Seweryniak, D Schwartz, J Warner, DD AF Mohammadi, S Regan, PH Vincent, SM Blumenthal, D Carpenter, M Davids, CN Gelletly, W Janssens, RVF Lister, CJ Pearson, CJ Simpson, J Seweryniak, D Schwartz, J Warner, DD TI High spin states in Ni-58 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID BAND AB The yrast states of the beta-stable nucleus Ni-58(28)30 have been studied using the reaction Ca-40(Mg-24. alpha 2p) Ni-58 at a beam energy of 65 MeV. Transitions in this nucleus were identified unambiguously using high-efficiency recoil-gated gamma-ray spectra obtained from the AYEBALL gamma-ray array in conjunction with the Argonne Fragment mass analyser coupled to a split anode ionization chamber. The decay scheme is presented and ii is hoped that such a study will shed light on the competition between core breaking and population of the g(9/2) neutron intruder orbitals in the generation of high angular momentum states in this region. C1 Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. RP Mohammadi, S (reprint author), Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 12 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 909 EP 912 DI 10.1088/0954-3899/25/4/067 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800067 ER PT J AU Vincent, SM Regan, PH Mohammadi, S Gelletly, W Blumenthal, D Carpenter, MP Davids, CN Janssens, RVF Lister, CJ Pearson, CJ Simpson, J Seweryniak, D Schwartz, J Warner, DD AF Vincent, SM Regan, PH Mohammadi, S Gelletly, W Blumenthal, D Carpenter, MP Davids, CN Janssens, RVF Lister, CJ Pearson, CJ Simpson, J Seweryniak, D Schwartz, J Warner, DD TI A yrast study of the A=61 isobars Cu-61(29) and Zn-61(30) SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on the Physics of Nuclear Structure at the Extremes CY JUN 17-19, 1998 CL LEWES, ENGLAND SP Univ Brighton ID MASS AB The high spin states in the the A = 61 isobars, Cu-61 and Zn-61 have been investigated using the AYEBALL gamma-ray array at the Argonne National Laboratory, Chicago. Channel selection following a fusion-evaporation reaction was made using the fragment mass analyser in conjunction with a split anode ionization chamber to obtain isotopically pure gamma-ray identification spectra. The decay schemes, together with spins assigned from a directional correlation analysis are presented and compared with previous work on these nuclei. C1 Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. RP Vincent, SM (reprint author), Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 6 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1999 VL 25 IS 4 BP 941 EP 943 DI 10.1088/0954-3899/25/4/075 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 193UP UT WOS:000080155800075 ER PT J AU Wang, J Kondrashov, D Liewer, PC Karmesin, SR AF Wang, J Kondrashov, D Liewer, PC Karmesin, SR TI Three-dimensional deformable-grid electromagnetic particle-in-cell for parallel computers SO JOURNAL OF PLASMA PHYSICS LA English DT Article AB We describe a new parallel, non-orthogonal-grid, three-dimensional electromagnetic particle-in-cell (EMPIC) code based on a finite-volume formulation. This code uses a logically Cartesian grid of deformable hexahedral cells, a discrete surface integral (DSI) algorithm to calculate the electromagnetic field, and a hybrid logical-physical space algorithm to push particles. We investigate the numerical instability of the DSI algorithm for non-orthogonal grids, analyse the accuracy for EMPIC simulations on non-orthogonal grids, and present performance benchmarks of this code on a pal allel supercomputer. While the hybrid particle push algorithm has a second-order accuracy in space, the accuracy of the DSI field solve algorithm is between first and second order for non-orthogonal grids. The parallel implementation of this code, which is almost identical to that of a Cartesian-grid EMPIC code using domain decomposition, achieved a high parallel efficiency of over 96% for large-scale simulations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Wang, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kondrashov, Dmitri/E-2067-2016 OI Kondrashov, Dmitri/0000-0002-3471-7275 NR 12 TC 12 Z9 12 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD APR PY 1999 VL 61 BP 367 EP 389 DI 10.1017/S0022377899007552 PN 3 PG 23 WC Physics, Fluids & Plasmas SC Physics GA 226JB UT WOS:000082015900001 ER PT J AU Wilson, BG Chen, MH AF Wilson, BG Chen, MH TI A revised algorithm for the computation of super-transition array spectra of hot dense plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB The formula for computing bound-bound X-ray absorption from unresolved 'Super'-transition arrays is reformulated in terms of correlated occupation numbers, averaged over subensembles of the ideal grand canonical ensemble. These can be expressed as generalized Fermi factors which depend on the ratio of partition functions. A new algorithm for the computation of this ratio is presented, hybridizing recursion relations starting from full or empty super-shells with an exact relation numerically stable about the average occupation of the supershell. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Wilson, BG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 5 TC 8 Z9 8 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR PY 1999 VL 61 IS 6 BP 813 EP 823 DI 10.1016/S0022-4073(98)00069-7 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 176ZH UT WOS:000079182000011 ER PT J AU Bowyer, TW Abel, KH Hubbard, CW Panisko, ME Reeder, PL Thompson, RC Warner, RA AF Bowyer, TW Abel, KH Hubbard, CW Panisko, ME Reeder, PL Thompson, RC Warner, RA TI Field testing of collection and measurement of radioxenon for the Comprehensive Test Ban Treaty SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article ID XE-133 AB Pacific Northwest National Laboratory, with guidance and support from the U.S. Department of Energy's NN-20 Comprehensive Test Ban Treaty (CTBT) Research and Development program, has developed and demonstrated a fully automatic sampler-analyzer (ARSA) for the collection and quantitative measurement of the four xenon radionuclides, Xe-131m (11.9 d), Xe-133m (2.19 d), Xe-133 (5.24 d), and Xe-135 (9.10 h), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a CTBT, and may have applications in stack monitoring and other areas where xenon radionuclides are present. The activity ratios between certain of these radionuclides permit discrimination between radioxenon originating from nuclear detonations and that from nuclear reactor operations, nuclear fuel reprocessing, or from medical isotope production and usage. With the ARSA system, xenon is continuously and automatically separated from the atmosphere at flow rates of about 100 lpm by sorption-bed techniques. Samples collected in 8 hours are automatically analyzed by electron-photon coincidence spectrometry to provide detection sensitivities as low as 100 mu Bq/m(3) of air. This sensitivity is about 10-fold better than achieved with reported laboratory-based procedures(1) for the short time collection intervals of interest. Gamma-ray energy spectra and gas analysis data are automatically collected. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Bowyer, TW (reprint author), Pacific NW Lab, POB 999,MSIN P8-08, Richland, WA 99352 USA. NR 19 TC 11 Z9 13 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD APR PY 1999 VL 240 IS 1 BP 109 EP 122 DI 10.1007/BF02349143 PG 14 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 191NB UT WOS:000080027500016 ER PT J AU Roane, JE DeVol, TA Leyba, JD Fjeld, RA AF Roane, JE DeVol, TA Leyba, JD Fjeld, RA TI Effects of ionic radiological and chemical interferences on the chromatographic separation of a radionuclide standard solution SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article AB For characterizing radioactive samples there are two major considerations in the application of a coupled liquid chromatography and on-line scintillation counting system: (1) radiological interferences and (2) chemical interferences from the matrix. A study was conducted to identify which interferences from typical matrices found at several Department of Energy facilities affected the separation of a radioactive tracer solution by the coupled system. The selection of potential interferent materials was determined through a review of characterization and monitoring studies of surface water, ground water, and high level waste tank supernatant at those facilities. Incremental mass loadings of contaminant were mixed with a standardized radioactive tracer (Fe-55, Ni-63, Sr-90 and Pm-147) and then injected into a coupled system. The resultant chromatograms were compared to the chromatogram of the standard radionuclide solution to determine the effects of the chemical or radiological constituent. Relative to the radionuclide solution, Cs-137 was the only activation/fission product used in this study to effect a radiological interference. For the natural uranium series, a radiological interference was observed for Sr-90 due to either a uranium isotope or a decay product of the series. No radiological interference was observed from Th-228, though it must be noted that the elution program was not capable of completely separating the decay series nuclides of natural uranium or thorium. For the chemical interferences, the effects are twofold since the chemical can affect the concentration of ions on the pre-concentration stage as well as the chromatographic separation. The general trend observed was that increasing the ionic strength of the chemical resulted in decreased retention fractions on the pre-concentration column and significant shifts in peak elution times. C1 Clemson Univ, Dept Environm Engn Sci, Clemson, SC 29634 USA. Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Roane, JE (reprint author), Clemson Univ, Dept Environm Engn Sci, Clemson, SC 29634 USA. NR 15 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD APR PY 1999 VL 240 IS 1 BP 197 EP 208 DI 10.1007/BF02349154 PG 12 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 191NB UT WOS:000080027500027 ER PT J AU Silver, GL AF Silver, GL TI Rearrangement equations for plutonium SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article ID PENTAVALENT PLUTONIUM; STABILITY AB The percents of all oxidation states produced by Pu disproportionation, including unreacted starting material, can be obtained by new equations that are easy to apply. The equations are useful for quantifying the extent and the stoichiometry of disproportionation, the consequences of complexation, and the effects of temperature changes on the composition of the oxidation-state mixture. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Silver, GL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS E502, Los Alamos, NM 87545 USA. NR 17 TC 23 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD APR PY 1999 VL 240 IS 1 BP 231 EP 235 DI 10.1007/BF02349159 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 191NB UT WOS:000080027500032 ER PT J AU Hinatsu, Y Wakeshima, M Edelstein, N Craig, I AF Hinatsu, Y Wakeshima, M Edelstein, N Craig, I TI Electron paramagnetic resonance spectrum of Pr4+ in Sr2CeO4 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID BACEO3 AB The electron paramagnetic resonance (EPR) spectra of Pr4+ diluted in Sr2CeO4 were measured at 4.2 K, A very large hyperfine interaction with the Pr-141 nucleus was observed. The spectra were anisotropic, due to the distortion of the octahedral oxygen coordination symmetry around the Pr4+ ion. The results were analyzed based on the weak field approximation, and the following g values and hyperfine coupling constants A were obtained: \g(parallel to)\ = 1.169, \g(perpendicular to)\ = 0.966, \A(parallel to)\ = 0.0703 cm(-1), and \A(perpendicular to)\ = 0.0669 cm(-1). The measured g values are smaller than \-10/7/, showing that the crystal field is effective to some extent on the behavior of a 4f electron in Sr2CeO4. (C) 1999 Academic Press. C1 Hokkaido Univ, Grad Sch Sci, Div Chem, Sapporo, Hokkaido 0600810, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Hinatsu, Y (reprint author), Hokkaido Univ, Grad Sch Sci, Div Chem, Sapporo, Hokkaido 0600810, Japan. RI Craig, Ian/C-3799-2009 OI Craig, Ian/0000-0003-4481-3700 NR 14 TC 12 Z9 12 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1999 VL 144 IS 1 BP 20 EP 24 DI 10.1006/jssc.1998.8047 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 196BE UT WOS:000080288500004 ER PT J AU Vogt, T Woodward, PM Hunter, BA AF Vogt, T Woodward, PM Hunter, BA TI The high-temperature phases of WO3 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID CRYSTAL-STRUCTURE; SUPERCONDUCTORS; PEROVSKITES AB High-temperature, high-resolution neutron powder diffraction experiments were performed to investigate the phases of WO3 between room temperature and 850 degrees C. Two phases were found and characterized by Rietveld refinements: orthorhombic beta-WO3 (Pbcn, a = 7.3331(2), b = 7.5733(2), c = 7.7401(3) Angstrom at 350 degrees C, tilt system a(0)b(+)c(-)) and tetragonal alpha-WO3 (P4/ncc, a = 5.2759(1), b = 5.2759(1), c = 7.8462(3) Angstrom at 800 degrees C, tilt system a(0)a(0)c(-)). The sequence of temperature-induced phase transitions in WO3 can be rationalized in terms of changes in the octahedral tilt systems and/or displacements of the tungsten out of the center of the WO6 octahedron. Above room temperature the two phase transitions are driven by sucessive softening of phonon modes, Mj at the alpha- to beta-transition and R-25 at the beta- to gamma-transition. (C) 1999 Academic Press. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Ohio State Univ, Newman & Wolfrom Lab, Dept Chem, Columbus, OH 43210 USA. Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. RP Vogt, T (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Vogt, Thomas /A-1562-2011 OI Vogt, Thomas /0000-0002-4731-2787 NR 26 TC 93 Z9 95 U1 10 U2 42 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1999 VL 144 IS 1 BP 209 EP 215 DI 10.1006/jssc.1999.8173 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 196BE UT WOS:000080288500029 ER PT J AU Vogt, T Woodward, PM Hunter, BA Prodjosantoso, AK Kennedy, BJ AF Vogt, T Woodward, PM Hunter, BA Prodjosantoso, AK Kennedy, BJ TI Sr3MO4F (M = Al, Ga) - A new family of ordered oxyfluorides SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID FLUORIDE AB Sr3MO4F has been synthesized for M = Al and Ga and shown by Rietveld refinement of neutron and synchrotron X-ray powder diffraction data to adopt a layered structure in which the oxygen and fluorine are ordered and located in different layers, (C) 1999 Academic Press. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. ANSTO, Neutron Scattering Grp, Lucas Hts, NSW 2234, Australia. Univ Sydney, Dept Chem, Sydney, NSW 2001, Australia. RP Vogt, T (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Vogt, Thomas /A-1562-2011; OI Vogt, Thomas /0000-0002-4731-2787; Kennedy, Brendan/0000-0002-7187-4579 NR 9 TC 42 Z9 45 U1 2 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1999 VL 144 IS 1 BP 228 EP 231 DI 10.1006/jssc.1999.8172 PG 4 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 196BE UT WOS:000080288500033 ER PT J AU Rard, JA AF Rard, JA TI Memorial tribute - Kenneth Sanborn Pitzer - 1914-1997 SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Biographical-Item C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Rard, JA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 1 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD APR PY 1999 VL 28 IS 4 BP 247 EP 264 PG 18 WC Chemistry, Physical SC Chemistry GA 216YE UT WOS:000081471400001 ER PT J AU Pitzer, KS Wang, PM Rard, JA Clegg, SL AF Pitzer, KS Wang, PM Rard, JA Clegg, SL TI Thermodynamics of electrolytes. 13. Ionic strength dependence of higher-order terms; Equations for CaCl2 and MgCl2 SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE electrolyte solutions; osmotic coefficient; activity coefficient; thermodynamics; calcium chloride; magnesium chloride ID AQUEOUS CALCIUM-CHLORIDE; OSMOTIC COEFFICIENTS; 25-DEGREES-C; SYSTEM AB While the original ion-interaction (Pitzer) equations of 1973 were adequate for many electrolytes to the limit of solubility, additional terms are needed for some systems of large solubility. A simple pattern of ionic-strength dependence is proposed for third, fourth, and higher virial coefficients. It is found to be very effective in representing the complex behavior of CaCl2(aq) as well as that of MgCl2(aq) at 25 degrees C. Equations without ion association are presented for each system that are valid for the full range to 11.0 and 5.9 mol-kg(-1), respectively, as well as simpler equations for limited molality ranges. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Earth & Environm Sci Di, Livermore, CA 94550 USA. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. RP Pitzer, KS (reprint author), OLI Syst Inc, 108 Amer Rd,Morris Plains, Morris Plains, NJ 07950 USA. NR 34 TC 56 Z9 59 U1 6 U2 28 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD APR PY 1999 VL 28 IS 4 BP 265 EP 282 DI 10.1023/A:1022695525943 PG 18 WC Chemistry, Physical SC Chemistry GA 216YE UT WOS:000081471400002 ER PT J AU Das, B Pitzer, KS AF Das, B Pitzer, KS TI Thermodynamic properties of aqueous potassium sulfate under superambient conditions SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE pressure dependence of thermodynamic properties; activity coefficients; osmotic coefficients; apparent molar volume; ion association; electrolytes; potassium sulfate ID ALKALI-METAL SULFATES; TEMPERATURE; NA2SO4(AQ) AB Using the ion-interaction or virial coefficient approach developed by Pitzer, the pressure dependencies of the osmotic and activity coefficients for K2SO4(aq) up to 225 degrees C and 0.65 mol-kg(-1) have been calculated from recent literature data on the apparent molar volumes of K2SO4(aq). These pressure dependencies were combined with the osmotic and activity coefficients at 1 bar or P-sat, obtained from the model of Holmes and Mesmer to yield a comprehensive set of thermodynamic properties of K2SO4(aq) at temperatures from 25 to 225 degrees C, pressures 100, 200, and 300 bars, and molalities to 0.65 mol-kg(-1). C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Das, B (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 12 TC 5 Z9 5 U1 1 U2 10 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD APR PY 1999 VL 28 IS 4 BP 283 EP 289 DI 10.1023/A:1022647610013 PG 7 WC Chemistry, Physical SC Chemistry GA 216YE UT WOS:000081471400003 ER PT J AU Holmes, HF Mesmer, RE AF Holmes, HF Mesmer, RE TI Isopiestic studies of H3PO4(aq) at elevated temperatures SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE H3PO4; isopiestic; high temperature; osmotic coefficients; activity coefficients ID THERMODYNAMIC PROPERTIES; AQUEOUS-SOLUTIONS; PHOSPHORIC-ACID; ELECTROLYTES; CONSTANT; WATER AB Isopiestic moralities of aqueous solutions of phosphoric acid have been measured at 383.15 to 523.15 K. NaCl(aq) served as the isopiestic standard for the calculation of osmotic coefficients. The ion-interaction model gave an excellent fit to the experimental osmotic coefficients by treating H3PO4(aq) as a 1-1 weak electrolyte. Activity coefficients, both real and stoichiometric, were also obtained from the analysis of the isopiestic results. As expected, the ionization of H3PO4(aq) decreased with increasing temperature. However, at higher molalities, the ionization increased with increasing molality (reionization). C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Holmes, HF (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 26 TC 4 Z9 4 U1 0 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD APR PY 1999 VL 28 IS 4 BP 327 EP 340 DI 10.1023/A:1022651710922 PG 14 WC Chemistry, Physical SC Chemistry GA 216YE UT WOS:000081471400005 ER PT J AU Fanghanel, T Konnecke, T Weger, H Paviet-Hartmann, P Neck, V Kim, JI AF Fanghanel, T Konnecke, T Weger, H Paviet-Hartmann, P Neck, V Kim, JI TI Thermodynamics of Cm(III) in concentrated salt solutions: Carbonate complexation in NaCl solution at 25 degrees C SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE trivalent actinides; curium; americium; solution thermodynamics; carbonate complexation; ionic strength; Pitzer model; concentrated solutions ID ELECTROLYTE-SOLUTIONS; TRIVALENT ACTINIDES; SOLUBILITY; SYSTEM AB The carbonate complexation reactions of Cm(III) were studied by time-resolved laser fluorescence spectroscopy in 0-6 m NaCl at 25 degrees C. The ionic strength dependence of the stepwise formation constants for the carbonate complexes Cm(CO3)(n)(3-2n) with n = 1, 2, 3, and 4 is described by modeling the activity coefficients of the Cm(III) species with Fitter's ion-interaction approach. Based on the present results and literature data for Cm(III) and Am (III), the mean carbonate complexation constants at I = 0 are calculated to be: log beta(101)(o) = 8.1 +/- 0.3, log beta(102)(o) = 13.0+/-0.6, log beta(103)(o) = 15.2+/-0.4, and log beta(104)(o) = 13.0+/-0.5. Combining these equilibrium constants at infinite dilution and the evaluated set of Pitzer parameters, a model is obtained, that reliably predicts the thermodynamics of trivalent actinide An(III) carbonate complexation in dilute to concentrated NaCl solution. C1 Forschungszentrum Karlsruhe, Inst Nukl Entsorgungstechn, D-76021 Karlsruhe, Germany. Florida Int Univ, Hemispher Ctr Environm Technol, Miami, FL 33174 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Fanghanel, T (reprint author), Forschungszentrum Karlsruhe, Inst Nukl Entsorgungstechn, Postfach 3640, D-76021 Karlsruhe, Germany. NR 34 TC 23 Z9 23 U1 0 U2 12 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD APR PY 1999 VL 28 IS 4 BP 447 EP 462 DI 10.1023/A:1022664013648 PG 16 WC Chemistry, Physical SC Chemistry GA 216YE UT WOS:000081471400011 ER PT J AU Colford, JM Tager, I Byers, LF Ricci, P Hubbard, A Horner, R AF Colford, JM Tager, I Byers, LF Ricci, P Hubbard, A Horner, R TI Methods for assessing the public health impact of outflows from combined sewer systems SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID ABSENCE AB Approximately 1,100 communities in the United States have combined sewer and stormwater systems whose capacity may be exceeded during moderate or heavy rainfall. Outflows may occur that can deposit water with varying concentrations of the components of sewage onto public areas, where contact with residents or workers is possible, potentially resulting in a range of adverse health effects. This study proposes and applies three analytic methods to evaluate the impact of such outflows on public health. C1 Univ Calif Berkeley, Sch Publ Hlth, Div Publ Hlth Biol & Epidemiol, Berkeley, CA 94720 USA. Stanford Linear Accelerator Ctr, Div Environm Safety & Hlth, Menlo Park, CA USA. Univ San Francisco, Dept Environm Management, San Francisco, CA 94117 USA. Univ Calif Berkeley, Sch Publ Hlth, Div Biostat & Informat Sci, Berkeley, CA 94720 USA. TRC Environm Solut Inc, No Calif, Walnut Creek, CA 94598 USA. RP Colford, JM (reprint author), Univ Calif Berkeley, Sch Publ Hlth, Div Publ Hlth Biol & Epidemiol, Berkeley, CA 94720 USA. NR 14 TC 2 Z9 2 U1 1 U2 2 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD APR PY 1999 VL 49 IS 4 BP 454 EP 462 PG 9 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 185KW UT WOS:000079669000008 PM 10232060 ER PT J AU Hsueh, CH Haynes, JA Lance, MJ Becher, PF Ferber, MK Fuller, ER Langer, SA Carter, WC Cannon, WR AF Hsueh, CH Haynes, JA Lance, MJ Becher, PF Ferber, MK Fuller, ER Langer, SA Carter, WC Cannon, WR TI Effects of interface roughness on residual stresses in thermal barrier coatings SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID OXIDATION-INDUCED STRESSES; BEHAVIOR; FILMS AB Using a newly developed object-oriented finite-element analysis method, both an actual microstructure and model microstructures of a plasma-sprayed thermal barrier coating system were numerically simulated to analyze the fullfield residual stresses of this coating system, Residual stresses in the actual microstructure were influenced by both the irregular top-coat/bond-coat interface and cracks in the top coat. By treating the microcracked top coat as a more-compliant solid microstructure, the effects of the irregular interface on residual stresses were examined. These results then could be compared to results that have been obtained by analyzing a model microstructure with a sinusoidal interface, which has been considered by some earlier investigators. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Rutgers State Univ, Dept Ceram & Mat Engn, Piscataway, NJ 08855 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011; Carter, W/K-2406-2012; Lance, Michael/I-8417-2016 OI Lance, Michael/0000-0001-5167-5452 NR 12 TC 62 Z9 63 U1 1 U2 17 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 APR PY 1999 VL 82 IS 4 BP 1073 EP 1075 PG 3 WC Materials Science, Ceramics SC Materials Science GA 189WK UT WOS:000079929000039 ER PT J AU Tompson, SR AF Tompson, SR TI Special libraries: A cataloging guide. SO JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE LA English DT Book Review C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Tompson, SR (reprint author), Fermi Natl Accelerator Lab, POB 500,MS 109, Batavia, IL 60510 USA. RI Tompson, Sara/D-6952-2011 NR 2 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0002-8231 J9 J AM SOC INFORM SCI JI J. Am. Soc. Inf. Sci. PD APR 1 PY 1999 VL 50 IS 4 BP 383 EP 384 DI 10.1002/(SICI)1097-4571(1999)50:4<383::AID-ASI18>3.0.CO;2-S PG 2 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA 178PL UT WOS:000079275000018 ER PT J AU Van Hoogmoed, L Rodger, LD Spier, SJ Gardner, IA Yarbrough, TB Snyder, JR AF Van Hoogmoed, L Rodger, LD Spier, SJ Gardner, IA Yarbrough, TB Snyder, JR TI Evaluation of peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity for detection of septic peritonitis in horses SO JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION LA English DT Article ID SPONTANEOUS BACTERIAL PERITONITIS; INFECTIOUS ARTHRITIS; ASCITIC FLUID; BACTERASCITES; EFFUSIONS; CIRRHOSIS; ACIDOSIS AB Objective-To determine whether peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity can be used to differentiate horses with septic peritonitis from those with nonseptic peritonitis, Design-Prospective study. Animals-46 horses, including 10 healthy horses, 15 horses with septic peritonitis, and 21 horses with nonseptic peritonitis. Procedure-Peritoneal fluid and blood samples were analyzed for pH, glucose concentration, and lactate dehydrogenase activity. Complete blood cell counts were performed, and peritoneal fluid samples were submitted for bacterial culture. Results-Horses with septic peritonitis had significantly lower peritoneal fluid pH and glucose concentrations than horses with nonseptic peritonitis and healthy horses. Compared with other tests, serum-toperitoneal fluid glucose concentration differences > 50 mg/dl had the highest diagnostic use for detection of septic peritonitis. Peritoneal fluid pH < 7.3, glucose concentration < 30 mg/dl, and fibrinogen concentration > 200 mg/dl were also highly indicative of septic peritonitis. Clinical Implications-Peritoneal fluid pH and glucose concentration can be used to assist in the identification of horses with septic peritonitis. These measurements can provide an early indication of sepsis, especially if cytologic evaluation of periloneal fluid is unavailable or results are equivocal and peritoneal fluid bacterial culture results are pending. C1 Univ Calif Lawrence Livermore Natl Lab, Sch Vet Med, Dept Med & Epidemiol, Davis, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Sch Vet Med, Dept Surg & Radiol Sci, Davis, CA 95616 USA. RP Spier, SJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Sch Vet Med, Dept Med & Epidemiol, Davis, CA 95616 USA. NR 42 TC 27 Z9 27 U1 0 U2 6 PU AMER VETERINARY MEDICAL ASSOC PI SCHAUMBURG PA 1931 N MEACHAM RD SUITE 100, SCHAUMBURG, IL 60173-4360 USA SN 0003-1488 J9 J AM VET MED ASSOC JI J. Am. Vet. Med. Assoc. PD APR 1 PY 1999 VL 214 IS 7 BP 1032 EP 1036 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA 182LW UT WOS:000079501300027 PM 10200799 ER PT J AU Wiench, JW Stefaniak, L Grech, E Bednarek, E AF Wiench, JW Stefaniak, L Grech, E Bednarek, E TI Two-amidine derivatives studied by H-1,C-13, N-14, N-15 NMR and GIAO-CHF calculations SO JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 LA English DT Article ID BASES; SOLVENTS AB H-1,C-13, N-14, and N-15 NMR data are presented for two amidine derivatives and their complexes with TFA in 1:1 and 1:2 molar ratios. The protonation site at the N5 atom was established based upon the observed coupling constants, NOE interactions, and chemical shift change. The GIAO-CHF calculations were also performed for the free bases and their N5 cations. C1 Polish Acad Sci, Inst Organ Chem, PL-01224 Warsaw, Poland. Tech Univ Szczecin, Inst Fundamental Chem, PL-71065 Szczecin, Poland. Drug Inst, PL-00725 Warsaw, Poland. RP Wiench, JW (reprint author), Iowa State Univ, Ames Lab, 229 Spedding Hall, Ames, IA 50011 USA. NR 11 TC 17 Z9 17 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0300-9580 J9 J CHEM SOC PERK T 2 JI J. Chem. Soc.-Perkin Trans. 2 PD APR PY 1999 IS 4 BP 885 EP 889 DI 10.1039/a806259e PG 5 WC Chemistry, Organic; Chemistry, Physical SC Chemistry GA 186UE UT WOS:000079747400032 ER PT J AU Doshi, R Richards, VL Carter, JD Wang, XP Krumpelt, M AF Doshi, R Richards, VL Carter, JD Wang, XP Krumpelt, M TI Development of solid-oxide fuel cells that operate at 500 degrees C SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID TRANSPORT AB Solid-oxide fuel cells based on doped ceria electrolytes and operating at 500 degrees C are shown to be feasible. The operating regime of doped ceria electrolytes is discussed. It is shown that the ionic conductivity of ceria-based fuel cells is sufficiently high for operation with hydrogen fuel at low temperatures. The major challenges of fabricating a thin electrolyte by a conventional method and the development of high-performance cathodes capable of operating at 500-600 degrees C are addressed. Cells based on thin-film ceria electrolytes also exhibited good open-circuit voltages between 0.97 and 1 V. Cathode materials with high performance have been developed from pyrochlores, perovskites, and cermets of silver and doped bismuth oxide. The advantages and disadvantages of different cathode materials are discussed. The maximum power density obtained at 500 degrees C was 140 mW/cm(2). (C) 1999 The Electrochemical Society. S0013-4651(98)04-033-6. All rights reserved. C1 Argonne Natl Lab, Electrochem Technol Program, Argonne, IL 60439 USA. Tri State Univ, Dept Mech & Aerosp Engn, Angola, IN USA. RP Doshi, R (reprint author), Argonne Natl Lab, Electrochem Technol Program, Argonne, IL 60439 USA. NR 18 TC 336 Z9 360 U1 5 U2 73 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 APR PY 1999 VL 146 IS 4 BP 1273 EP 1278 DI 10.1149/1.1391758 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 187WK UT WOS:000079811000006 ER PT J AU Chen, YF Devine, TM Evans, JW Monteiro, OR Brown, IG AF Chen, YF Devine, TM Evans, JW Monteiro, OR Brown, IG TI Examination of the corrosion behavior of aluminum current collectors in lithium/polymer batteries SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID PROPYLENE CARBONATE; PASSIVITY; FILMS; ALLOYS; STEEL AB The corrosion behavior of aluminum, a candidate material for the current collectors of the positive electrodes of lithium-polymer batteries, in contact with a lithium polymer electrolyte was examined in both batteries and three-electrode electrochemical cells. The results indicate aluminum is resistant to uniform corrosion in the polymer electrolyte: poly(ethylene oxide)-LiN(CF3SO2)(2) but can be susceptible to pitting corrosion. Localized pitting corrosion occurs on the aluminum current collector during overcharging of the battery. Fitting corrosion only occurred in the electrochemical cells when the aluminum electrode was anodically polarized to potentials that were considerably greater than those that resulted in pitting corrosion in batteries. The greater susceptibility of the aluminum current collectors of batteries to pitting corrosion is attributed to inhomogeneous current flow through the current collector. This results in local breakdown of the passive film on aluminum at sites of locally high current density. The inhomogeneous current density that flows through the aluminum/cathode interface is. caused by the presence of discrete paths through the cathode with low electrical resistance. In an effort to improve the localized corrosion behavior of aluminum electrodes, it was found that surfaces impregnated by ion implantation with similar to 20 atom % tungsten exhibited enhanced resistance to pitting corrosion in poly(ethylene oxide)-LiN(CF3SO2)(2). (C) 1999 The Electrochemical Society. S0013-4651(97)12-120-6. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. RP Chen, YF (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 15 TC 29 Z9 31 U1 2 U2 20 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 APR PY 1999 VL 146 IS 4 BP 1310 EP 1317 DI 10.1149/1.1391763 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 187WK UT WOS:000079811000011 ER PT J AU Bloom, I Lanagan, MT Krumpelt, M Smith, JL AF Bloom, I Lanagan, MT Krumpelt, M Smith, JL TI The development of LiFeO2-LiCoO2-NiO cathodes for molten carbonate fuel cells SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID OXIDE AB The phase relationship in the LiFeO2-LiCoO2-NiO ternary system were determined and used to find compositions that would reduce the resistivity of LiFeO2-containing cathodes to levels low enough for molten carbonate fuel cells. There was no solubility limit in the NiO-LiFeO2 binary system; a continuous solution was formed, Two regions of homogeneity were found in the LiFeO2-LiCoO2 binary, 0 to 13 and 87 to 100 mol % LiCoO2. Similarly, two regions of homogeneity were found in the LiCoO2-NiO binary, 0 to 18 and 94 to 100 mol % LiCoO2. The resistivities of these materials indicate that addition of Ni and Co to the LiFeO2 lattice decreases the resitivity from about 300 Omega cm to about 1 to 10 Omega cm at 650 degrees C, Using both Ni and Co additives together reduces the resistivity of LiFeO2 and its sensitivity to CO2 partial pressure. Cell tests indicate that solid solutions LiFeO2-LiCoO2-NiO system posses electrocatalytic activity. The cell displayed a potential of 0.79 V at 160 mA/cm(2). The data indicate that LiFeO2-LiCoO2-NiO cathodes hold promise for Fuel-cell cathodes. (C) 1999 The Electrochemical Society. S0013-4651(98)06-071-6. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Electrochem Technol Program, Argonne, IL 60439 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Bloom, I (reprint author), Argonne Natl Lab, Div Chem Technol, Electrochem Technol Program, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 25 TC 25 Z9 26 U1 0 U2 16 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 APR PY 1999 VL 146 IS 4 BP 1336 EP 1340 DI 10.1149/1.1391766 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 187WK UT WOS:000079811000014 ER PT J AU Smith, AV Gehr, RJ Bowers, MS AF Smith, AV Gehr, RJ Bowers, MS TI Numerical models of broad-bandwidth nanosecond optical parametric oscillators SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID BETA-BARIUM BORATE; SPECTRAL PROPERTIES; KTIOPO4 CRYSTALS; GENERATION; FREQUENCY; PULSE; DIFFERENCE AB We present three new methods for modeling broad-bandwidth, nanosecond optical parametric oscillators in the plane-wave approximation. Each accounts for the group-velocity differences that determine the operating linewidth of unseeded optical parametric oscillators, and each allows the signal and the idler waves to develop from quantum noise. The first two methods are based on split-step integration methods in which nonlinear mixing and propagation are calculated separately on alternate steps. One method relies on Fourier transforming the fields between t and w to handle propagation, with mixing integrated over a Delta z step; the other transforms between z and k(z) in the propagation step, with mixing integrated over Delta t. The third method is based on expansion of the three optical fields in terms of their respective longitudinal empty cavity modes, taking into account the cavity boundary conditions. Equations describing the time development of the mode amplitudes are solved to yield the time dependence of the three output fields. These models exclude diffraction and group-velocity dispersion but can be readily extended to include them. (C) 1999 Optical Society of America [S0740-3224(99)02103-7] OCIS codes: 190.2620, 190.4410, 190.4970, 230.4320, 140.3430. C1 Sandia Natl Labs, Dept 1128, Lasers Opt & Remote Sensing, Albuquerque, NM 87185 USA. Aculight Corp, Bothell, WA 98011 USA. RP Smith, AV (reprint author), Sandia Natl Labs, Dept 1128, Lasers Opt & Remote Sensing, POB 5800, Albuquerque, NM 87185 USA. NR 27 TC 52 Z9 54 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1999 VL 16 IS 4 BP 609 EP 619 DI 10.1364/JOSAB.16.000609 PG 11 WC Optics SC Optics GA 184VD UT WOS:000079633700014 ER PT J AU Chen, CH Nakada, S Shieh, YN DePaolo, DJ AF Chen, CH Nakada, S Shieh, YN DePaolo, DJ TI The Sr, Nd and O isotopic studies of the 1991-1995 eruption at Unzen, Japan SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Unzen volcano; isotopic study; phenocrysts ID CHEMICAL GEODYNAMICS; SOUTHWEST JAPAN; VOLCANO JAPAN; DACITE DOME; MAGMA; CONTAMINATION; SYSTEMATICS; PHENOCRYSTS; DIFFUSION; CRUSTAL AB The magma generation at Unzen volcano may be considered as the product of crustal material mixed with mantle magma accompanied by fractional crystallization (AFC), The magma in the Unzen volcano is estimated to consist of about 50-80% of residual magma (F) and about 30-70% assimilated crustal material (A) relative to the original magma. Concerning the 1991-1995 eruption, it is estimated that the magma formed as the result of mixing of about 50-60% crustal material and about 55-65% of residual magma, An alternative magma eruption model for the 1991-1995 eruption is proposed here. In the early stage, the isotopic characteristics of 1991 eruption are defined by AFC process in the deeper magma chamber, Later, the magma ascended through the conduit and quiescently stayed for a long time in a shallow reservoir before eruption, The minerals continuously crystallized as phenocrysts especially at the chilled top and outer margin in the shallow chamber, The crystallized phenocryst mush was reworked into the central part of the magma chamber by means of magma convection and rapid magma ascent. Therefore, the reaction between phenocrysts and melt occurs only in internal chemical disequilibrium in the magma chamber. In contrast, the isotopic compositions of the original magma shall be little influenced by the above processes throughout its eruptive history. The 1991-1995 eruptive rocks of the Unzen volcano show their characteristics in Sr and Nd isotopic values independent of their two previous eruptions. However, the isotopic values of early eruptive product could represent the original magma value. This result also supports the previous work of Chen et al, (1993) [Chen, C.H., DePaolo, D.J,, Nakada, S., Shieh, Y.N., 1993. Relationship between eruption volume and neodymium isotopic composition at Unzen volcano. Nature 362, 831-834], that suggested the epsilon Nd of early or precursory eruptive products could be a qualitative indicator of the maximum size of a continuing or impending eruption, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Acad Sinica, Inst Earth Sci, Taipei 115, Taiwan. Univ Tokyo, Volcano Res Ctr, Tokyo 1130032, Japan. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. Univ Calif Berkeley, Dept Geol & Geophys, Ctr Isotope Geochem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Chen, CH (reprint author), Acad Sinica, Inst Earth Sci, POB 1-55, Taipei 115, Taiwan. NR 30 TC 14 Z9 14 U1 1 U2 6 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 APR PY 1999 VL 89 IS 1-4 BP 243 EP 253 DI 10.1016/S0377-0273(99)00002-5 PG 11 WC Geosciences, Multidisciplinary SC Geology GA 195GX UT WOS:000080243200019 ER PT J AU Foltz, CJ Ullman-Cullere, M AF Foltz, CJ Ullman-Cullere, M TI Guidelines for assessing the health and condition of mice SO LAB ANIMAL LA English DT Article ID END-POINT; SCIENTIFIC PROCEDURES; EXPERIMENTAL-ANIMALS; LABORATORY-ANIMALS; PAIN; DISTRESS; DISCOMFORT; RODENT; DEATH; RATS AB With the development of transgenic and targeted mutant (knockout) technologies over the past 10 years, there has been an increase in the number of investigators using mice; the number of mice used in biomedical research; the number of mice bred and maintained to their natural life spans; and the number of mice with potentially adverse or debilitating phenotypes. The authors present practical guidelines for assessing and monitoring the health of these mice. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. MIT, Ctr Canc Res, Div Biol, Cambridge, MA 02139 USA. MIT, Div Comparat Med, Cambridge, MA 02139 USA. RP Foltz, CJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, Bear Creek Rd, Oak Ridge, TN 37831 USA. NR 30 TC 39 Z9 39 U1 1 U2 12 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 0093-7355 J9 LAB ANIMAL JI Lab Anim. PD APR PY 1999 VL 28 IS 4 BP 28 EP 32 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA 184FB UT WOS:000079598800007 ER PT J AU Whitney, EM Kendall, RP Brickey, MR Coombs, SE Duda, CA Duda, VK AF Whitney, EM Kendall, RP Brickey, MR Coombs, SE Duda, CA Duda, VK TI Integrated reservoir management for the long term - The Carpinteria offshore field SO MARINE GEORESOURCES & GEOTECHNOLOGY LA English DT Article; Proceedings Paper CT 4th Symposium on Studies Related to Continental Margins - A Summary of Year-Nine and Year-Ten Activities CY NOV 16-19, 1997 CL CORPUS CHRISTI, TEXAS SP US Dept Interior, Minerals Management Serv, Assoc Amer St Geologists Continental Margins Comm AB The Carpinteria offshore field, Santa Barbara, California, has produced more than 200 million barrels of oil to dare. This mature field has continued operations in an economically and politically challenging environment that finally resulted in the abandonment of the field's California state leases by the lease holder. The abandoned leases, together with adjoining federal leases, are now operated by an independent producer. Los Alamos National Laboratory has joined with that independent operator, Pacific Operators Offshore, and with the State Lands Commission of California and the Minerals Management Service in a unique collaborative effort to redevelop the mature field This project is a part of a larger umbrella project, the Advanced Reservoir Management project (ARM) that is designed to demonstrate the worth of advanced computational tools and state-of-the-art methods for independent oil and gas producers. The Carpinteria Reservoir Redevelopment project takes a long-term view of reservoir management; as a result, our management plan includes a continuing investment in rime and technology to understand the reservoir better. In particular, we have completed an extensive reservoir characterization and geological modeling effort that has created a self-consistent model, satisfying geophysical, geological, and engineering data constraints. We have begun the engineering-intensive flow simulation phase of the project using the current geological description of the reservoir and are confident that our careful efforts in geological modeling will result in a reasonable reservoir flow model. C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Geoanal Grp EES S, Los Alamos, NM 87545 USA. Minerals Management Serv, Washington, DC 20240 USA. Calif State Lands Commis, Long Beach, CA USA. RP Whitney, EM (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Geoanal Grp EES S, POB 1663,MS-F665, Los Alamos, NM 87545 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 1064-119X J9 MAR GEORESOUR GEOTEC JI Mar. Geores. Geotechnol. PD APR-SEP PY 1999 VL 17 IS 2-3 BP 103 EP 116 DI 10.1080/106411999273756 PG 14 WC Engineering, Ocean; Engineering, Geological; Oceanography; Mining & Mineral Processing SC Engineering; Oceanography; Mining & Mineral Processing GA 205MU UT WOS:000080825800007 ER PT J AU Frost, BG Voelkl, E AF Frost, BG Voelkl, E TI A study of electric charging using low-magnification electron holography SO MATERIALS CHARACTERIZATION LA English DT Article; Proceedings Paper CT Fall 1997 Meeting of the Materials-Research-Society CY DEC 01-05, 1997 CL BOSTON, MASSACHUSETTS SP Mat Res Soc ID P-N-JUNCTIONS; FIELDS AB As experimentally found by low-magnification holography, both the size of the condenser aperture and the excitation of the objective lens strongly modify the object wavefunction of an electron wave. For example, the phase by electrically charged polystyrene latex spheres attached to a copper grid increases with decreasing excitation of the objective lens and/or decreasing diameter of the condenser aperture. It was also found that a smaller diameter of the condenser aperture increases the phase shift by a carbon foil or magnetic memory cells. In addition, the phase of the image wave is modified by the lateral position of the aperture, whereas different electron densities of the imaging beam have only minor influence on the detected phase shifts. (C) Elsevier Science Inc., 1999. All rights reserved. C1 Univ Tennessee, EM Facil, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Frost, BG (reprint author), Univ Tennessee, EM Facil, Knoxville, TN 37996 USA. NR 16 TC 6 Z9 6 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 APR-MAY PY 1999 VL 42 IS 4-5 BP 221 EP 227 DI 10.1016/S1044-5803(99)00026-1 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 239JH UT WOS:000082764600007 ER PT J AU Voelkl, E Allard, LF Frost, B AF Voelkl, E Allard, LF Frost, B TI Recording, display, and evaluation methods to obtain quantitative information from electron holograms SO MATERIALS CHARACTERIZATION LA English DT Article; Proceedings Paper CT Fall 1997 Meeting of the Materials-Research-Society CY DEC 01-05, 1997 CL BOSTON, MASSACHUSETTS SP Mat Res Soc ID RESOLUTION AB Digital recording has become a basic requirement for electron holography for many reasons. The fact that it allows live-time evaluation of the phase information and easy recording of a reference hologram are two very important reasons that are widely appreciated. Here we will discuss requirements for recording electron holograms under the special conditions imposed by the Nyquist limit and the modulation transfer function (MTF) of the charge-coupled device (CCD) camera. As electron holography provides complex images carrying both the amplitude and phase of the image wave, the question of how to best display the information will be investigated. This is not an easy question, because special aspects of different applications require different solutions. Methods for display and evaluation of holographic data are described. Published by Elsevier Science Inc., 1999. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Voelkl, E (reprint author), Oak Ridge Natl Lab, MS 6064,POB 2008, Oak Ridge, TN 37831 USA. NR 13 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 APR-MAY PY 1999 VL 42 IS 4-5 BP 307 EP 319 DI 10.1016/S1044-5803(99)00023-6 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 239JH UT WOS:000082764600014 ER PT J AU Natarajan, A Wang, W Ma, E Bhattacharya, RN Blaugher, RD AF Natarajan, A Wang, W Ma, E Bhattacharya, RN Blaugher, RD TI Magnetoresistivity measurements of Tl1Ba2Ca2Cu3Ox (Tl-1223) high temperature superconductor films synthesized via an electrodeposited precursor SO MATERIALS LETTERS LA English DT Article DE magnetoresistivity; superconductor; thallium-1223 films; electrodeposition AB Superconducting Tl1Ba2Ca2Cu3Ox (Tl-1223) thin films were synthesized via an electrodeposited Ba2Ca2Cu3Ox (BCCO) precursor doped with Ag. The effect of magnetic field on the resistivity-temperature behavior of the Tl-1223 films was investigated at temperatures close to its critical temperature. The magnetoresistivity characteristics observed at low to medium fields and their implications are discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Louisiana State Univ, Dept Mech Engn, Microsyst Engn Team Mu SET, Baton Rouge, LA 70803 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Louisiana State Univ, Dept Mech Engn, Microsyst Engn Team Mu SET, Baton Rouge, LA 70803 USA. RI Ma, En/A-3232-2010 NR 7 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X EI 1873-4979 J9 MATER LETT JI Mater. Lett. PD APR PY 1999 VL 39 IS 1 BP 58 EP 62 DI 10.1016/S0167-577X(98)00217-1 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 188QX UT WOS:000079860800012 ER PT J AU Wright, JK Williamson, RL Renusch, D Veal, B Grimsditch, M Hou, PY Cannon, RM AF Wright, JK Williamson, RL Renusch, D Veal, B Grimsditch, M Hou, PY Cannon, RM TI Residual stresses in convoluted oxide scales SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE residual stress; ruby fluorescence; finite element modeling; convoluted coatings; protective oxides; alumina ID SINGLE-CRYSTAL; OXIDATION; ALLOYS; BEHAVIOR; ALPHA-AL2O3; INTERFACE; COATINGS; GROWTH AB Alumina scales that grow during oxidation of FeCrAl alloys can develop a convoluted morphology. Although convolution relieves the overall growth stress, high thermal stresses develop locally and can he detrimental to the scale or interface integrity. Ruby fluorescence measurements and finite element simulations are used to examine residual thermal stresses and strains that result when the convoluted scales are cooled to room temperature. Unlike a flat scale that is in biaxial compression, a convoluted scale contains significant gradients, with tensile stress components along the outside and near the interface of the convoluted peaks. The experimental results are in good agreement with model calculations and provide much needed verification of the model assumptions. Because the ruby fluorescence technique provides only the hydrostatic stress averaged over an excited volume that includes the entire alumina scale thickness, modeling provides derail and insight to the experimental measurements. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Idaho Natl Lab, Idaho Falls, ID 83415 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wright, JK (reprint author), Idaho Natl Lab, POB 1625, Idaho Falls, ID 83415 USA. EM jk3@inel.gov OI Wright, Jill/0000-0001-8909-8144; Williamson, Richard/0000-0001-7734-3632 NR 37 TC 45 Z9 46 U1 1 U2 7 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 APR 1 PY 1999 VL 262 IS 1-2 BP 246 EP 255 DI 10.1016/S0921-5093(98)01020-X PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 177VE UT WOS:000079231100029 ER PT J AU Elnagar, GN Khamayseh, A AF Elnagar, GN Khamayseh, A TI Numerical solution of non-stationary aero-autoelasticity integro-differential operator equations SO MATHEMATICAL METHODS IN THE APPLIED SCIENCES LA English DT Article ID INTEGRODIFFERENTIAL EQUATIONS; CHEBYSHEV AB The spectral method of G. N. Elnagar, which yields spectral convergence rate for the approximate solutions of Fredholm and Volterra-Hammerstein integral equations, is generalized in order to solve the larger class of integro-differential functional operator equations with spectral accuracy. In order to obtain spectrally accurate solutions, the grids on which the above class of problems is to be solved must also be obtained by spectrally accurate techniques. The proposed method is based on the idea of relating, spectrally constructed, grid points to the structure of projection operators which will be used to approximate the control vector and the associated state vector. These projection operators are spectrally constructed using Chebyshev-Gauss-Lobatto grid points as the collocation points, and Lagrange polynomials as trial functions. Simulation studies demonstrate computational advantages relative to other methods in the literature. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ S Carolina, Dept Math & Comp Sci, Spartanburg, SC 29303 USA. Univ Calif Los Alamos Natl Lab, Computat Sci Methods Grp, Los Alamos, NM 87545 USA. RP Elnagar, GN (reprint author), Univ S Carolina, Dept Math & Comp Sci, 800 Univ Way, Spartanburg, SC 29303 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0170-4214 J9 MATH METHOD APPL SCI JI Math. Meth. Appl. Sci. PD APR PY 1999 VL 22 IS 6 BP 501 EP 513 DI 10.1002/(SICI)1099-1476(199904)22:6<501::AID-MMA47>3.0.CO;2-1 PG 13 WC Mathematics, Applied SC Mathematics GA 182ZR UT WOS:000079528500003 ER PT J AU Walter, PL AF Walter, PL TI Dynamic force, pressure, & acceleration measurement - Part 1 - The applicable conceptual & dynamic transducer models SO MEASUREMENTS & CONTROL LA English DT Article AB The measurement of time-varying physical phenomena, specifically force;pressure,and acceleration , presents a significant challenge to the engineer. This 12 part course will explain the "why" associated with the importance of various measurement-system consideration;It is is oriented to the senior technician or practicing engineer who has a fundamental understanding of transducers and associated signal conditioning and who wants to design and apply measurement systems that gu;guarantee the acquisition of meaningful data from transducers. Part I provides both a conceptual and a dynamic model for transducers. While initially these models may appear esoteric, their understanding will help optimize measurement-system design for the applications of interest. Part 2 discusses the properties of-both silicon and piezoelectric materials that make them optimum choices for incorporation into transducers intended to measure time-varying phenomena. Part 3 describes the characteristics of the time-varying signals that will be measured. Part 4 deals with interfacing the transducer to the environment to be measured. The performance of the transducer can be degraded or the environment to be measured modified, depending on hero this interface is accomplished. Part 5 explains the system requirements for linearity, flat amplitude response, and linear phase response when making time-varying measurements. Data filtering is then discussed in Part 6. Part 7 presents useful "rules of thumb" when designing measurement systems and interpreting data. Part 8 deals both with the calibration of the types of transducers of interest and the calibration of measurement systems in the field. Part 9 discusses how to determine if data recordings are free of noise. Part 10 then looks at some applications of the measured data: integration, differentiation, pourer spectral densities, Fourier spectra, shock spectra, etc. Part II describes how frequency response functions derived from acceleration data enable dynamic characterization of structural systems. Finally, Part 12 identifies other information sources available to anyone interested in measuring the time-varying physical phenomena that are the topic of this text. It also provides a measurement-planning check list. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Walter, PL (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU MEASUREMENTS & DATA CORP PI PITTSBURGH PA 2994 W LIBERTY AVE, PITTSBURGH, PA 15216 USA SN 0148-0057 J9 MEAS CONTROL-US JI Meas. Control PD APR PY 1999 IS 194 BP 90 EP 96 PG 7 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA 198GR UT WOS:000080415600003 ER PT J AU Mason, TA Adams, BL AF Mason, TA Adams, BL TI Use of microstructural statistics in predicting polycrystalline material properties SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID EFFECTIVE ELASTIC PROPERTIES; COMPOSITE-MATERIALS; CONSTANTS; BOUNDS; DIFFRACTION; TEXTURES; METALS; MODULI; COPPER AB Experimental measurements of lattice orientation correlation in an oxygen-free electronic (OFE) copper plate have been employed in several statistical continuum mechanical theories to construct improved bounds and estimates of the plate's macroscopic elastic response. One- and two-point microstructural statistics of lattice orientation were obtained through the automated analysis of spatially resolved electron backscatter diffraction (EBSD) patterns. Generalized Hashin-Shtrikman (GHS) bounds incorporating two-point statistical data were found to be 75 pet narrower than the Voigt-Reuss bounds, A perturbation expansion technique yielded two sets of bounds of comparable quality. An experimental acoustic measurement of the bulk elastic response of the plate was found to lie between the calculated bounds. In addition, a perturbation estimate was obtained which exceeds the measured response, but still falls within all of the calculated bounds. The influence of crystallographic texture was investigated for a variety of simulated textured copper polycrystals and was found to cause significant differences in the macroscopic elastic properties. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. RP Mason, TA (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. NR 51 TC 40 Z9 40 U1 1 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 APR PY 1999 VL 30 IS 4 BP 969 EP 979 DI 10.1007/s11661-999-0150-5 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 180XK UT WOS:000079411000008 ER PT J AU Misra, A Gibala, R AF Misra, A Gibala, R TI Slip transfer and dislocation nucleation processes in multiphase ordered Ni-Fe-Al alloys SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID TEMPERATURE DEFORMATION-BEHAVIOR; SINGLE-CRYSTALS; METALS AB Directionally solidified (DS) alloys with the nominal composition Ni-30 at. pet Fe-20 at. pet Al having eutectic microstructures were used to study slip transfer across interphase boundaries and dislocation nucleation at the interfacial steps. The slip transfer from the ductile second phase, gamma(fcc) containing ordered gamma'(L1(2)) precipitates, to the ordered beta(B2) phase and the generation of dislocations at the interface steps were interpreted using the mechanisms proposed for similar processes involving grain boundaries in polycrystalline single-phase materials. The criteria for predicting the slip systems activated as a result of slip transfer across grain boundaries were found to be applicable for interphase boundaries in the multiphase ordered Ni-Fe-Al alloys. The potential of tailoring the microstructures and interfaces to promote slip transfer and thereby enhance the intrinsic ductility of dislocation-density-limited intermetallic alloys is discussed. C1 Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. RP Misra, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 35 TC 27 Z9 27 U1 0 U2 7 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 APR PY 1999 VL 30 IS 4 BP 991 EP 1001 DI 10.1007/s11661-999-0152-3 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 180XK UT WOS:000079411000010 ER PT J AU Misra, A Gibala, R Noebe, RD AF Misra, A Gibala, R Noebe, RD TI Deformation and fracture behavior of a directionally solidified beta/gamma ' Ni-30 at. pct Al alloy SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID THERMOELASTIC MARTENSITIC-TRANSFORMATION; MECHANICAL-PROPERTIES; TWEED MICROSTRUCTURES; ELECTRON-MICROSCOPY; STRUCTURAL LEDGES; SINGLE-CRYSTALS; BOUNDARIES; PHASE; DISLOCATION; DUCTILITY AB The effect of a ductile gamma'-Ni3Al phase on the room-temperature ductility, temperature-dependent yield strength, and creep resistance of beta-NiAl was investigated. Room-temperature tensile ductility of up to 9 pet was observed in directionally solidified beta/gamma' Ni-30 at, pet Al alloys, whereas the ductility of directionally solidified (DS), single-phase [001] beta-NiAl was negligible. The enhancement in ductility was attributed to a combination of slip transfer from the ductile gamma' to the brittle beta phase and extrinsic toughening mechanisms such as crack blunting, deflection, and bridging. As in single phase Ni3Al, the temperature-dependent yield strength of these two-phase alloys increased with temperature with a peak at approximately 850 K. The creep strength of the beta/gamma' alloys in the temperature range 1000 to 1200 K was found to be comparable to that of monolithic beta-NiAl. A creep strengthening phase needs to be incorporated in the beta/gamma' microstructure to enhance the elevated temperature mechanical properties. C1 Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Misra, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 58 TC 19 Z9 20 U1 0 U2 4 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 APR PY 1999 VL 30 IS 4 BP 1003 EP 1015 DI 10.1007/s11661-999-0153-2 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 180XK UT WOS:000079411000011 ER PT J AU Suryanarayana, C Korth, GE AF Suryanarayana, C Korth, GE TI Consolidation of nanocrystalline powders SO METALS AND MATERIALS-KOREA LA English DT Article DE consolidation; nanocrystalline powders; titanium aluminides; hot isostatic pressing; ceracon processing; shock consolidation; transmission electron microscopy ID TITANIUM ALUMINIDES AB Blended elemental Ti-24Al-11Nb (at.%) and Ti-55Al (at.%) powders were mechanically alloyed and consolidated to full density by hot isostatic pressing (HIPing), Ceracon processing, and shock consolidation methods. Nanometer-sized grains were observed in all the samples, the finest size achieved in the shock-consolidated samples. The grain size was larger at higher HIPing temperatures. In comparison with conventional coarse-grained material, the HIP temperature for full consolidation could be brought down by about 400 degrees C for the nanostructured titanium aluminides. C1 Colorado Sch Mines, Dept Met & Mat Engn, Golden, CO 80401 USA. Lockheed Martin Idaho Technol Co, Div Met & Ceram, Idaho Falls, ID 83415 USA. RP Suryanarayana, C (reprint author), Colorado Sch Mines, Dept Met & Mat Engn, Golden, CO 80401 USA. RI Suryanarayana, C/B-9314-2008 NR 22 TC 7 Z9 7 U1 1 U2 4 PU KOREAN INST METALS MATERIALS PI SEOUL PA POSCO CENTER, 4TH FL (EAST WING), 892 DAECHI-4-DONG, KANGNAM-KU, SEOUL 135-777, SOUTH KOREA SN 1225-9438 J9 MET MATER-KOREA JI Met. Mater.-Korea PD APR PY 1999 VL 5 IS 2 BP 121 EP 128 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 202QA UT WOS:000080662600004 ER PT J AU Milcamps, A de Bruijn, FJ AF Milcamps, A de Bruijn, FJ TI Identification of a novel nutrient-deprivation-induced Sinorhizobium meliloti gene (hmgA) involved in the degradation of tyrosine SO MICROBIOLOGY-UK LA English DT Article DE Rhizobium; starvation; homogentisate dioxygenase; maleylacetoacetate isomerase; glutathione S-transferase ID BACTERIUM SHEWANELLA-COLWELLIANA; GLUTATHIONE S-TRANSFERASES; STATIONARY-PHASE SURVIVAL; ESCHERICHIA-COLI; RHIZOBIUM-MELILOTI; CARBON-STARVATION; PHOSPHATE STARVATION; MELANIN BIOSYNTHESIS; HOMOGENTISIC ACID; VIBRIO-CHOLERAE AB Sinorhirobium meliloti strain N4 carries a Tn5luxAB insertion in a gene which is induced by nitrogen and carbon deprivation as well as in the presence of tyrosine. The Tn5luxAB-tagged locus was found to share significant similarity with the human hmgA gene and the corresponding Aspergillus nidulans gene, encoding the enzyme homogentisate dioxygenase, which is involved in the degradation of tyrosine. Extended DNA sequence analysis of the tagged locus revealed the presence of several ORFs, including one encoding a polypeptide sharing a high degree of similarity with human and fungal maleylacetoacetate isomerases. Strain N4 was found to be unable to use tyrosine as carbon source, to lack homogentisate dioxygenase activity, to produce a melanin-like pigment and to be affected in stationary-phase survival. This is believed to be the first report of a hmgA-homologous gene in bacteria. C1 Michigan State Univ, NSF Ctr Microbial Ecol, E Lansing, MI 48824 USA. Michigan State Univ, MSU DOE Plant Res Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. RP de Bruijn, FJ (reprint author), Michigan State Univ, NSF Ctr Microbial Ecol, E Lansing, MI 48824 USA. EM debruijn@pilot.msu.edu NR 75 TC 34 Z9 39 U1 0 U2 2 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING, BERKS, ENGLAND RG7 1AE SN 1350-0872 J9 MICROBIOL-UK JI Microbiology-(UK) PD APR PY 1999 VL 145 BP 935 EP 947 PN 4 PG 13 WC Microbiology SC Microbiology GA 184QP UT WOS:000079624700018 PM 10220173 ER PT J AU Bruno, WJ Halpern, AL AF Bruno, WJ Halpern, AL TI Topological bias and inconsistency of maximum likelihood using wrong models SO MOLECULAR BIOLOGY AND EVOLUTION LA English DT Letter DE long branches attract; most likely unresolved tree; positively misleading ID PHYLOGENETIC METHODS; PRODUCE C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Mexico, Hlth Sci Ctr, Dept Mol Genet & Microbiol, Albuquerque, NM 87131 USA. RP Bruno, WJ (reprint author), Mail Stop K-710, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [5P20-RR11830-02] NR 8 TC 81 Z9 83 U1 0 U2 0 PU SOC MOLECULAR BIOLOGY EVOLUTION PI LAWRENCE PA PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0737-4038 J9 MOL BIOL EVOL JI Mol. Biol. Evol. PD APR PY 1999 VL 16 IS 4 BP 564 EP 566 PG 3 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 186WA UT WOS:000079752600013 PM 10331281 ER PT J AU Spear, KE Besmann, TM Beahm, EC AF Spear, KE Besmann, TM Beahm, EC TI Thermochemical modeling of glass: Application to high-level nuclear waste glass SO MRS BULLETIN LA English DT Article ID PHASE-DIAGRAMS; THERMODYNAMIC PROPERTIES; SYSTEMS; OPTIMIZATION; TEMPERATURE; NA2O-SIO2 C1 Penn State Univ, University Pk, PA 16802 USA. Oak Ridge Natl Lab, Div Met & Ceram, Res Grp, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Spear, KE (reprint author), Penn State Univ, 118 Steidle Bldg, University Pk, PA 16802 USA. NR 26 TC 28 Z9 28 U1 1 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD APR PY 1999 VL 24 IS 4 BP 37 EP 44 PG 8 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 185JH UT WOS:000079665300018 ER PT J AU Akerlof, C Balsano, R Barthelmy, S Bloch, J Butterworth, P Casperson, D Cline, T Fletcher, S Frontera, F Gisler, G Heise, J Hills, J Kehoe, R Lee, B Marshall, S McKay, T Miller, R Piro, L Priedhorsky, W Szymanski, J Wren, J AF Akerlof, C Balsano, R Barthelmy, S Bloch, J Butterworth, P Casperson, D Cline, T Fletcher, S Frontera, F Gisler, G Heise, J Hills, J Kehoe, R Lee, B Marshall, S McKay, T Miller, R Piro, L Priedhorsky, W Szymanski, J Wren, J TI Observation of contemporaneous optical radiation from a gamma-ray burst SO NATURE LA English DT Article ID AFTERGLOW AB The origin of gamma-ray bursts (GRBs) has been enigmatic since their discovery(1). The situation improved dramatically in 1997, when the rapid availability of precise coordinates(2,3) for the bursts allowed the detection of faint optical and radio afterglows-optical spectra thus obtained have demonstrated conclusively that the bursts occur at cosmological distances. But, despite efforts by several groups(4-7), optical detection has not hitherto been achieved during the brief duration of a burst. Here we report the detection of bright optical emission from GRB990123 while the burst was still in progress. Our observations begin 22 seconds after the onset of the burst and show an increase in brightness by a factor of 14 during the first 25 seconds; the brightness then declines by a factor of 100, at which point (700 seconds after the burst onset) it falls below our detection threshold. The redshift of this burst, z approximate to 1.6 (refs 8, 9), implies a peak optical luminosity of 5 x 10(49) erg s(-1) Optical emission from gamma-ray bursts has been generally thought to take place at the shock fronts generated by interaction of the primary energy source with the surrounding medium, where the gamma-rays might also be produced The lack of a significant change in the gamma-ray light curve when the optical emission develops suggests that the gamma-rays are not produced at the shock front, but closer to the site of the original explosion(10). C1 Univ Michigan, Ann Arbor, MI 48109 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. Raytheon Syst, Lanham, MD 20706 USA. Univ Ferrara, I-44100 Ferrara, Italy. Space Res Org, Utrecht, Netherlands. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Inst Astrofis Spaziale, Rome, Italy. RP Akerlof, C (reprint author), Univ Michigan, Ann Arbor, MI 48109 USA. RI Barthelmy, Scott/D-2943-2012; McKay, Timothy/C-1501-2009; PIRO, LUIGI/E-4954-2013; OI McKay, Timothy/0000-0001-9036-6150; PIRO, LUIGI/0000-0003-4159-3984; Priedhorsky, William/0000-0003-0295-9138 NR 33 TC 558 Z9 566 U1 0 U2 6 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 1 PY 1999 VL 398 IS 6726 BP 400 EP 402 DI 10.1038/18837 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 182PW UT WOS:000079508200044 ER PT J AU Cowin, JP Tsekouras, AA Iedema, MJ Wu, K Ellison, GB AF Cowin, JP Tsekouras, AA Iedema, MJ Wu, K Ellison, GB TI Immobility of protons in ice from 30 to 190 K SO NATURE LA English DT Article ID WATER; DYNAMICS; IONS; ENERGIES AB The anomalously fast motion of hydronium ions (H3O+) in water is often attributed to the Grotthuss mechanism(1,2): whereby protons tunnel from one water molecule to the next. This tunnelling is relevant to proton motion through water in restricted geometries, such as in 'proton wires' in proteins(3) and in stratospheric ice particls(4). Transport of hydronium ions in ice is thought to be closely related to its transport in water(1,2). But whereas claims have been made that such tunnelling can pe;sist even at OK in ice(5-7), counter-claims suggest that the activation energy for hydronium motion in ice is non-zero(8-10). Here we use 'soft-landing'(11-13) of hydronium ions on the surface of ice to show that the ions do not seem to move at all at temperatures below 190 K, This implies not only that hydronium motion is an activated process, but also that it does not occur at anything like the rate expected from the Grotthuss mechanism. We also observe the motion of an important kind of defect in ice's hydrogen-bonded structure (the D defect). Extrapolation of our measurements to 0 K indicates that the defect is still mobile at this temperature, in an electric field of 1.6 x 10(8) V m(-1). C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Athens, Chem Phys Lab, GR-15771 Athens, Greece. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Cowin, JP (reprint author), Pacific NW Natl Lab, Box 999,MS K8-88, Richland, WA 99352 USA. RI Wu, Kai/A-4903-2011 OI Wu, Kai/0000-0002-5016-0251 NR 22 TC 110 Z9 110 U1 4 U2 20 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 1 PY 1999 VL 398 IS 6726 BP 405 EP 407 DI 10.1038/18848 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 182PW UT WOS:000079508200046 ER PT J AU Sieker, LC Holmes, M Le Trong, I Turley, S Santarsiero, BD Liu, MY LeGall, J Stenkamp, RE AF Sieker, LC Holmes, M Le Trong, I Turley, S Santarsiero, BD Liu, MY LeGall, J Stenkamp, RE TI Alternative metal-binding sites in rubrerythrin SO NATURE STRUCTURAL BIOLOGY LA English DT Editorial Material ID DESULFOVIBRIO-VULGARIS RUBRERYTHRIN; PROTEIN; PURIFICATION; CENTERS; ENZYME C1 Univ Washington, Dept Biol Struct, Seattle, WA 98195 USA. Univ Washington, Biomol Struct Ctr, Seattle, WA 98195 USA. Fred Hutchinson Canc Res Ctr, Seattle, WA 98104 USA. EO Lawrence Berkeley Natl Lab, Div Phys Biosci, Berkeley, CA 94720 USA. Univ Georgia, Dept Biochem & Mol Biol, Athens, GA 30602 USA. Univ Nova Lisboa, Inst Tecnol Quim & Biol, P-2780 Oeiras, Portugal. RP Stenkamp, RE (reprint author), Univ Washington, Dept Biol Struct, Box 357420, Seattle, WA 98195 USA. NR 13 TC 18 Z9 19 U1 0 U2 0 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD APR PY 1999 VL 6 IS 4 BP 308 EP 309 PG 2 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 182MT UT WOS:000079503300007 PM 10201393 ER PT J AU Wojciak, JM Connolly, KM Clubb, RT AF Wojciak, JM Connolly, KM Clubb, RT TI NMR structure of the Tn916 integrase-DNA complex SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID SITE-SPECIFIC RECOMBINATION; SIDE-CHAIN RESONANCES; CRYSTAL-STRUCTURE; LARGER PROTEINS; CONJUGATIVE TRANSPOSITION; C-13 MAGNETIZATION; COUPLING-CONSTANTS; BINDING DOMAINS; BACKBONE AMIDE; SPECTRA AB The integrase protein catalyzes the excision and integration of the Tn916 conjugative transposon, a promiscuous genetic element that spreads antibiotic resistance in pathogenic bacteria. The solution structure of the N-terminal domain of the Tn916 integrase protein bound to its DNA-binding site within the transposon arm has been determined. The structure reveals an interesting mode of DNA recognition, in which the face of a three-stranded antiparallel beta-sheet is positioned within the major groove. A comparison to the structure of the homing endonuclease I-Ppol-DNA complex suggests that the three-stranded sheet may represent a new DNA-binding motif whose residue composition and position within the major groove are varied to alter specificity. The structure also provides insights into the mechanism of conjugative transposition. The DNA in the complex is bent similar to 35 degrees and may, together with potential interactions between bound integrase proteins at directly repeated sites, significantly bend the arms of the transposon. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, US DOE, Lab Struct Biol & Genet, Los Angeles, CA 90095 USA. RP Clubb, RT (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 405 Hilgard Ave, Los Angeles, CA 90095 USA. EM rclubb@mbi.ucla.edu NR 51 TC 47 Z9 49 U1 0 U2 2 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD APR PY 1999 VL 6 IS 4 BP 366 EP 373 PG 8 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 182MT UT WOS:000079503300020 PM 10201406 ER PT J AU Huckaby, JL Evans, JC Olsen, KB Antoniak, ZI Julya, JL Sklarew, DS AF Huckaby, JL Evans, JC Olsen, KB Antoniak, ZI Julya, JL Sklarew, DS TI He and SF6 as tracers for determining ventilation rates of high-level radioactive waste tanks SO NUCLEAR ENERGY-JOURNAL OF THE BRITISH NUCLEAR ENERGY SOCIETY LA English DT Article DE tracer; sulphur hexafluoride; helium ID METHANE EMISSIONS; SULFUR-HEXAFLUORIDE; GAS AB Helium (He) and sulphur hexafluoride (SF6) were used as tracers to determine passive ventilation rates of eight high-level radioactive waste storage tanks at the US Department of Energy's Hanford, Site. Measurements of passive ventilation rates are needed for resolution of several safety issues, including rates of flammable gas ventilation, drying rates of organic salt-nitrate salt mixtures, and estimation of organic liquid waste surface area. Both He and SF6 met the criteria of having low background levels in the tank headspaces, being rapidly dispersed in the headspace, and remaining well-mixed for the duration of the experiments. However, SF6 was lost at a faster rate than He from higher-temperature tanks. This accelerated loss was attributed to beta radiolysis of the SF6 associated with its large electron-capture cross-section. Thus, SF6 is not a reliable tracer in these high-level radioactive waste storage tanks. Passive ventilation rates were significantly different among the tanks studied and also exhibited temporal variation within given tanks. Ventilation rates were higher than expected based on modeling of barometric pressure fluctuations. Rates may be influenced by a combination of factors, including wind scavenging, temperature differentials, and available airflow pathways. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Huckaby, JL (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 20 TC 0 Z9 0 U1 0 U2 2 PU BRITISH NUCLEAR ENERGY SOC PI WESTMINSTER, LONDON PA 1-7 GREAT GEORGE ST, WESTMINSTER, LONDON, ENGLAND SW1P 3AA SN 0140-4067 J9 NUCL ENERG-J BR NUCL JI Nucl. Energy-J. Br. Nucl. Energy Soc. PD APR PY 1999 VL 38 IS 2 BP 99 EP 105 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 242GW UT WOS:000082933000016 ER PT J AU Kessel, CE Bretz, NL AF Kessel, CE Bretz, NL TI Plasma boundary reconstruction from reflectometer arrays SO NUCLEAR FUSION LA English DT Article AB A poloidal array of reflectometers can measure local density profiles near the plasma edge. The use of this constant density surface near the plasma boundary to reconstruct the magnetic geometry is examined. This approach for plasma boundary reconstruction is most useful for fully formed plasmas where the density gradients are near to, and perpendicular to, the reflectometer antennas. For ITER this plasma boundary information would supplement the magnetic reconstruction and can be used to correct the drifts in the steady state phase. The number and location of reflectometers is analysed to determine the accuracy of the plasma reconstruction and the need for additional information. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Kessel, CE (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 6 TC 4 Z9 4 U1 0 U2 2 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 1999 VL 39 IS 4 BP 445 EP 449 DI 10.1088/0029-5515/39/4/101 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 198QJ UT WOS:000080435200001 ER PT J AU Brooks, JN Whyte, DG AF Brooks, JN Whyte, DG TI Modelling and analysis of DIII-D/DiMES sputtered impurity transport experiments SO NUCLEAR FUSION LA English DT Article ID ELECTRON-IMPACT IONIZATION; RECOMMENDED DATA; ASDEX-UPGRADE; D DIVERTOR; EROSION; REDEPOSITION; LIMITER; PROFILES; CARBON; ATOMS AB A comprehensive modelling effort to analyse sputtering erosion and redeposition in the DIII-D/DiMES 70, 71 and 79 experiments using metal films (beryllium, vanadium, molybdenum, tungsten) on a carbon divertor probe hay been performed. These materials were exposed at the outer strike point of an attached H mode plasma with peak at T-e similar to 75 eV. The analysis uses coupled impurity transport (REDEP, WBC) and related codes with inputs of measured plasma parameters. The code output was compared with measured erosion and redeposition profiles, and other data. The predicted redeposition profiles for beryllium, carbon, molybdenum and tungsten agree well with the data. Beryllium and carbon exhibit longer transport distances compared with those of high-Z metals - primarily due to longer mean free paths for sputtered atom ionization. Photon emission calculations for beryllium also compare well with the data, thereby tending to validate coupled models for plasma parameters, impurity transport and atomic data. For vanadium the comparison of the code with the data varies from poor to fair depending on the ionization model used. For most metal films, the absolute erosion is less than that predicted for the 'pure' metal, a fact iue attribute to the effect of a carbon overlay or mixture. For carbon the predicted peak net erosion rate (similar to 4 nm/s) is approximately 5 times less than the gross rate, and this is confirmed by the data. Carbon net erosion and core contamination result primarily from the quiescent (intra-ELM) period oblique incidence deuterium physical sputtering and self-sputtering. ELM period sputtering: and chemical erosion appear to play a small role in net erosion in these plasmas. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif San Diego, San Diego, CA 92103 USA. RP Brooks, JN (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 23 Z9 23 U1 0 U2 5 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 1999 VL 39 IS 4 BP 525 EP 538 DI 10.1088/0029-5515/39/4/309 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 198QJ UT WOS:000080435200009 ER PT J AU Kinsey, JE AF Kinsey, JE TI Time dependent transport simulations of JET H mode plasmas SO NUCLEAR FUSION LA English DT Article ID PROFILE DATABASE; TOKAMAK; CONFINEMENT; TEMPERATURE; DISCHARGES; STABILITY; DIVERTOR; BETA AB A drift, wa-ve based transport model is used to self-consistently predict the time evolution of temperature and density profiles in JET H mode tokamak discharges. It is found that the same theoretically derived gyro-Bohm transport model previously used to simulate systematic scans of L mode discharges is equally successful in modelling JET ELMy H mode plasmas, implying that care transport is not intrinsically different from L mode confinement. The only difference between the L mode and H mode simulations results from the boundary conditions (i.e. density and temperature pedestals), which are taken from experimental data in both cases. Here, standardized experimental data from 16 JET H mode discharges in the ITER Profile Database are used, including dimensionless parameter scans in relative gyro-radius rho(*), collisionality nu and plasma beta. Imperfections in dimensionless similarity for three pairs of scans in relative gyro-radius cause a purely gyro-Bohm transport model to exhibit worse than gyro-Bohm confinement. For the beta scan, the model indicates a somewhat stronger beta dependence than that observed with a thermal energy confinement scaling of B tau proportional to beta(-0.7). More than half of the predicted beta scaling is found to result from finite-beta effects in the model. The model demonstrates a collisionality scaling of B tau proportional to nu(*)(-0.3) with some unfavourable dependence arising from neoclassical transport in the plasma core region. The overall goodness of fit obtained when comparing the global and local predictions results. in a root mean square error averaging less than 13% for the total stored energy and averaging less than Sro for the density and temperature profiles relative to the maximum experimental values. When E x B shear effects are added to the model, the resulting change in the mean RMS error for the temperature profiles is less than 4%. C1 Gen Atom Co, San Diego, CA USA. RP Kinsey, JE (reprint author), Oak Ridge Associated Univ, Oak Ridge, TN 37830 USA. NR 37 TC 14 Z9 14 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 1999 VL 39 IS 4 BP 539 EP 550 DI 10.1088/0029-5515/39/4/310 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 198QJ UT WOS:000080435200010 ER PT J AU Bultmann, S Crabb, DG Day, DB Fatemi, RD Gardner, B Harris, CM Johnson, JR McCarthy, JS McKee, PM Meyer, W Penttila, SI Ponikvar, E Rijllart, A Rondon, OA St Lorant, S Tobias, WA Trentalange, S Zhu, W Zihlmann, B Zimmermann, D AF Bultmann, S Crabb, DG Day, DB Fatemi, RD Gardner, B Harris, CM Johnson, JR McCarthy, JS McKee, PM Meyer, W Penttila, SI Ponikvar, E Rijllart, A Rondon, OA St Lorant, S Tobias, WA Trentalange, S Zhu, W Zihlmann, B Zimmermann, D TI A study of lithium deuteride as a material for a polarized target SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE polarized target; lithium deuteride; spin; structure functions ID DEEP-INELASTIC-SCATTERING; STRUCTURE-FUNCTION G1(X); SPIN STRUCTURE; PRECISION-MEASUREMENT; PROTON; NUCLEAR AB Experiment E155 at the Stanford Linear Accelerator Center (SLAC) measured the spin-dependent structure of the proton and neutron, using for the first time (LiD)-Li-6 as the polarized deuteron target material in a high-energy electron beam. This compound provides a significantly higher dilution factor than any other solid deuteron target material currently used in high-energy physics experiments. Results of the polarization behavior of the (LiD)-Li-6 target material before and after exposure to the 50 GeV/c electron beam used in E155 are presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CERN, CH-1211 Geneva 23, Switzerland. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90024 USA. Ruhr Univ Bochum, Fak Phys, D-44780 Bochum, Germany. RP Bultmann, S (reprint author), Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. RI Rondon Aramayo, Oscar/B-5880-2013; Day, Donal/C-5020-2015 OI Day, Donal/0000-0001-7126-8934 NR 29 TC 14 Z9 14 U1 0 U2 8 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 APR 1 PY 1999 VL 425 IS 1-2 BP 23 EP 36 DI 10.1016/S0168-9002(98)01341-2 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900003 ER PT J AU Carlsten, BE Palmer, DT AF Carlsten, BE Palmer, DT TI Enhanced emittance compensation in a high-frequency RF photoinjector using RF radial focusing SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID FREE-ELECTRON LASER; PERFORMANCE; ACCELERATOR; DESIGN AB Emittance compensation using the static axial magnetic field from a solenoid surrounding an RF photoinjector has been used to reduce the r.m.s. emittance of the electron beam by up to an order of magnitude, for photoinjectors ranging from 433 MHz to 3 GHz. The residual emittance after standard solenoidal compensation is typically a strong function of both solenoid position and focusing strength. It has been observed in both simulations and experiments that the residual emittance is larger than one would expect for higher-frequency photoinjectors, which use higher gradients. In this paper, we investigate why this happens, and show that enhanced compensation for higher-frequency photoinjectors can be achieved with the addition of radial RF focusing near the cathode. We numerically demonstrate that (1) lower residual emittances are possible if RF focusing is introduced, (2) the residual emittance is less sensitive to solenoid position, (3) the residual emittance is less sensitive to solenoid strength, and (4) the optimal solenoid position is further from the photoinjector cathode, leading to less stringent design requirements, especially at high frequencies. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Carlsten, BE (reprint author), Univ Calif Los Alamos Natl Lab, LANSCE-9,MS H851, Los Alamos, NM 87545 USA. NR 16 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1999 VL 425 IS 1-2 BP 37 EP 50 DI 10.1016/S0168-9002(98)01344-8 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900004 ER PT J AU Nelyubin, V Fujiwara, M Nakano, T Wojtsekhowski, B AF Nelyubin, V Fujiwara, M Nakano, T Wojtsekhowski, B TI Compton back-scattering of X-photons from 8 GeV electrons at SPring-8 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE polarized gamma beam; Compton back scattering; X-ray beam; undulator radiation; multilayer mirror; beam colliding; synchrotron radiation ID PHYSICS AB The experimental feasibility of using an intensive photon beam at the SPring-8 for producing a high-energy gamma-ray beam is examined. Compton back-scattering of the soft X-photons emitted by an undulator and reflected back by a multi-layer mirror from the electron beam can produce a quasi-monochromatic gamma-ray beam up to an energy very close to 8 GeV. The intensity of the gamma-ray beam in the energy range of 6.6-7.8 GeV has been estimated at 2 x 10(4) per second. The energy shape and the scattered angle of gamma-rays produced in Compton back-scattering of the soft X-photons from an 8 GeV electron beam are calculated. (C) 1999 Elsevier Science B.V. All rights reserved. C1 St Petersburg Nucl Phys Inst, Gatchina 188350, Russia. Osaka Univ, Nucl Phys Res Ctr, Osaka 5670047, Japan. Japan Atom Energy Res Inst, Adv Sci Res Ctr, Tokai, Ibaraki 3191195, Japan. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Nelyubin, V (reprint author), St Petersburg Nucl Phys Inst, Gatchina 188350, Russia. NR 11 TC 4 Z9 5 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1999 VL 425 IS 1-2 BP 65 EP 74 DI 10.1016/S0168-9002(98)01396-5 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900007 ER PT J AU Baarmand, MM Vaniachine, A Bonushkin, Y Matthey, C Hauser, J Muller, T Otwinowski, S Zeng, J Chrisman, D Giacomelli, P Gorn, W Layter, JG Minor, C Schenk, P Durkin, S Hoftiezer, J Lennous, P Ling, TY Rush, C Ferguson, T Hirschfelder, J Hoorani, H Fitch, J Gorn, L Korytov, A Mitselmakher, G Kisselev, O Prokofiev, O Smirnov, I Soulimov, V Klem, DE Vercelli, T Wuest, C Medved, S Preston, L Santiard, JC von Goeler, E AF Baarmand, MM Vaniachine, A Bonushkin, Y Matthey, C Hauser, J Muller, T Otwinowski, S Zeng, J Chrisman, D Giacomelli, P Gorn, W Layter, JG Minor, C Schenk, P Durkin, S Hoftiezer, J Lennous, P Ling, TY Rush, C Ferguson, T Hirschfelder, J Hoorani, H Fitch, J Gorn, L Korytov, A Mitselmakher, G Kisselev, O Prokofiev, O Smirnov, I Soulimov, V Klem, DE Vercelli, T Wuest, C Medved, S Preston, L Santiard, JC von Goeler, E TI Spatial resolution attainable with cathode strip chambers at the trigger level SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A simple network of comparators applied to the strip signals of a cathode strip chamber allows quick hit localization to within a halfstrip width, or +/- a quarter-strip. A six-plane chamber with 6.4 mm wide strips was tested in a high-energy muon beam. The chamber was placed behind a 30 cm thick iron block. We show that patterns of hits localized to within a halfstrip allowed us To identify 300 GeV/c muon tracks with 99% probability and 0.7 mm spatial resolution in the presence of bremsstrahlung radiation. This technique of finding muon tracks will be used in the cathode strip chambers of the CMS Endcap Muon System. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Riverside, Riverside, CA 92521 USA. SUNY Stony Brook, Stony Brook, NY 11790 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Ohio State Univ, Columbus, OH 43210 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. MIT, Cambridge, MA 02139 USA. Univ Florida, Gainesville, FL 32611 USA. Petersburg Nucl Phys Inst, Gatchina, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Purdue Univ, W Lafayette, IN 47907 USA. CERN, CH-1211 Geneva 23, Switzerland. Northeastern Univ, Boston, MA 02115 USA. RP Chrisman, D (reprint author), Univ Calif Riverside, Riverside, CA 92521 USA. RI Giacomelli, Paolo/B-8076-2009; Vanyashin, Aleksandr/H-7796-2013; Ferguson, Thomas/O-3444-2014; Hoorani, Hafeez/D-1791-2013; OI Vanyashin, Aleksandr/0000-0002-0367-5666; Ferguson, Thomas/0000-0001-5822-3731; Baarmand, Marc/0000-0002-9792-8619; Giacomelli, Paolo/0000-0002-6368-7220 NR 6 TC 11 Z9 11 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 APR 1 PY 1999 VL 425 IS 1-2 BP 92 EP 105 DI 10.1016/S0168-9002(98)01390-4 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900010 ER PT J AU Van Ginneken, A Neuffer, DV AF Van Ginneken, A Neuffer, DV TI Muon collection channel SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SIMULATION AB A preliminary analysis of the collection channel for a muon collider is presented. Pions, produced in a target by 8-30 GeV protons, are captured and transported in a solenoid where they decay into muons. Muon yield and phase space characteristics at the end of the channel can be improved by placing RF cavities and absorbers along the decay channel as well as by providing a supplemental toroidal field in conjunction with the absorbers. Results of Monte Carlo simulations are presented for a few such scenarios. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Van Ginneken, A (reprint author), Fermi Natl Accelerator Lab, POB 500,MS 306, Batavia, IL 60510 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1999 VL 425 IS 1-2 BP 165 EP 187 PG 23 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900013 ER PT J AU Borchi, E Bruzzi, M Li, Z Pirollo, S AF Borchi, E Bruzzi, M Li, Z Pirollo, S TI A two-level model for heavily irradiated silicon detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SEMICONDUCTORS; CAPACITANCE; DEFECT AB The Fermi level pinning at a boundary value of approximate to E-v + 0.5 eV, observed in heavily irradiated silicon, has been described considering two main traps related to divacancy (V-2) and carbon-oxygen complex (CiOi), with energy levels at E-c - 0.46 eV (acceptor) and E-v + 0.36 eV (donor), respectively. The appearance of a double junction in irradiated p(+)/n/n(+) silicon detectors is discussed in the framework of the proposed model. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 INFM Firenze, I-50139 Florence, Italy. Dipartimento Energet, I-50139 Florence, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Borchi, E (reprint author), INFM Firenze, Via S Marta 3, I-50139 Florence, Italy. EM bruzzi@fi.infn.it RI Bruzzi, Mara/K-1326-2015 OI Bruzzi, Mara/0000-0001-7344-8365 NR 21 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1999 VL 425 IS 1-2 BP 343 EP 346 DI 10.1016/S0168-9002(98)01378-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900027 ER PT J AU Charlton, LA Jerde, E Glasgow, DC Gabriel, TA AF Charlton, LA Jerde, E Glasgow, DC Gabriel, TA TI Foil analysis of 1.5-GeV proton bombardment of a mercury target SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutronic calculations; foil analysis; Hg cross sections ID SPALLATION AB The number of reactant nuclei in a series of foils surrounding a container of mercury that has been bombarded by 1.5-GeV protons is calculated and compared with experimental measurements. This procedure is done to aid in the validation of the mercury cross sections used in the design studies of the Spallation Neutron Source (SNS). It is found that the calculations match the measurements to within the uncertainties inherent in the analysis. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37831 USA. Oak Ridge Res Inst, Oak Ridge, TN 37830 USA. RP Charlton, LA (reprint author), Oak Ridge Natl Lab, Computat Phys & Engn Div, POB 2008, Oak Ridge, TN 37831 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1999 VL 425 IS 1-2 BP 371 EP 376 DI 10.1016/S0168-9002(98)01349-7 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900031 ER PT J AU Zholents, A Heimann, P Zolotorev, M Byrd, J AF Zholents, A Heimann, P Zolotorev, M Byrd, J TI Generation of subpicosecond X-ray pulses using RF orbit deflection SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A technique is proposed for producing high average intensity X-ray radiation from a storage ring for studies of the ultrafast phenomena on a subpicosecond time scale. Two RF cavity accelerating structures excited in the E-110 mode can be installed in a storage ring to create vertical displacements of electrons correlated with their longitudinal position in the bunch. The magnitude of these displacements can be sufficient for the X-ray radiation of the electron bunch between accelerating structures to be viewed as produced by a large number of independent sources, each of a subpicosecond duration. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Zholents, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 5 TC 98 Z9 100 U1 1 U2 9 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 APR 1 PY 1999 VL 425 IS 1-2 BP 385 EP 389 DI 10.1016/S0168-9002(98)01372-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 183LK UT WOS:000079554900033 ER PT J AU Lee, CL Zhou, XL AF Lee, CL Zhou, XL TI Thick target neutron yields for the Li-7(p,n)Be-7 reaction near threshold SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article DE boron neutron capture therapy; near-threshold BNCT; thick target neutron production; Li-7(p,n)Be-7 reaction ID CAPTURE THERAPY AB Transportable accelerator sources of epithermal neutrons are crucial for the development of hospital-based boron neutron capture therapy (BNCT) as a treatment modality for brain cancers. One method for producing such epithermal neutrons is near-threshold (p,n) reactions as studied by our group; as well as several other investigators. As part of this effort, we have developed accurate methods for computing the angular distributions and energy spectra of neutrons from thick targets using the Li-7(p,n)Be-7 reaction near threshold. Neutron yields are calculated for lithium metal as well as several lithium compounds of low molecular weight. The calculational method is discussed; with emphasis on the improvements over previously published methods. Neutron energy spectra, angular distributions, and total yields for proton beam energies up to 120 keV above threshold are presented. A method is also demonstrated for calculating neutron yields for targets that are not sufficiently thick to slow protons past the reaction threshold. (C) 1999 Elsevier Science B.V. All rights reserved. C1 MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. RP Lee, CL (reprint author), Univ Calif Los Alamos Natl Lab, X-CI,MS F663, Los Alamos, NM 87545 USA. NR 18 TC 80 Z9 83 U1 0 U2 7 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 APR PY 1999 VL 152 IS 1 BP 1 EP 11 DI 10.1016/S0168-583X(99)00026-9 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 180XH UT WOS:000079410800001 ER PT J AU Torok, I Papp, T Raman, S AF Torok, I Papp, T Raman, S TI Energy systematics of the K alpha L-i satellite transitions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on PIXE and its Analytical Applications CY JUN 14-18, 1998 CL LUND UNIV, LUND, SWEDEN SP Crafoord Fdn, Nobel Comm Phys, Swedish Royal Acad Sci, Swedish Res Council Engn Sci, Swedish Res Council Forestry & Agr Sci, Swedish Nat Sci Res Council, Lund Univ, Lund Inst Technol, Natl Electrostat Corp HO LUND UNIV DE X-ray emission spectra; multiple ionization satellites ID X-RAY; ATOMS; COLLISIONS; SHIFTS; IONS AB The presence of X-ray satellites is common in X-ray spectra. The last compilation of satellite lines, frequently cited in the open literature, is the X-ray energy collection of Cauchois and Senemaud, Wavelengths of X-ray Emission Lines and Absorption Edges, Pergamon, Oxford, 1978 [1], which is restricted to electron and photon excitations. In the last decades, many ion-induced satellite measurements have been performed, the range covered in Ref, [1] have been extended for similar to 40 < Z < 92, spectator vacancy number from 2 to 7, and energy-shifts from similar to 200 to 1200 eV. In analytical work and in basic atomic physics research one needs the best data available on the satellite lines. We are working on a new and comprehensive compilation of experimental values for the K-satellite, and K-hypersatellite energy shifts. Some problems encountered during this work are discussed. A new semi-empirical formula for the description of the K alpha L' satellite energy shifts is given. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Hungarian Acad Sci, Inst Nucl Res, ATOMKI, H-4001 Debrecen, Hungary. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Torok, I (reprint author), Hungarian Acad Sci, Inst Nucl Res, ATOMKI, PF 51, H-4001 Debrecen, Hungary. NR 10 TC 20 Z9 20 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 APR PY 1999 VL 150 IS 1-4 BP 8 EP 13 DI 10.1016/S0168-583X(98)01045-3 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 192AZ UT WOS:000080056500003 ER PT J AU Clark, BM Mangelson, NF St Clair, LL Gardner, JS Cooper, LS Rees, LB Grant, PG Bench, GS AF Clark, BM Mangelson, NF St Clair, LL Gardner, JS Cooper, LS Rees, LB Grant, PG Bench, GS TI Analysis of lichen thin sections by PIXE and STIM using a proton microprobe SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on PIXE and its Analytical Applications CY JUN 14-18, 1998 CL LUND UNIV, LUND, SWEDEN SP Crafoord Fdn, Nobel Comm Phys, Swedish Royal Acad Sci, Swedish Res Council Engn Sci, Swedish Res Council Forestry & Agr Sci, Swedish Nat Sci Res Council, Lund Univ, Lund Inst Technol, Natl Electrostat Corp HO LUND UNIV DE proton microprobe; PIXE; lichen; element distribution ID MICROSCOPY AB In order to better understand the distribution pattern of mineral elements in lichen tissues, thin sections (15 mu m) of the foliose, vagrant soil Lichen Xanthoparmelia chlorochroa were examined using proton microprobe Particle induced X-ray emission (PIXE). This technique was used to make two-dimensional scans, with 5 mu m resolution, across tissue cross sections of the test species. Element maps for Si. P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, and As have been prepared. Several elements are strongly localized in the element maps. PINE data are complimented with STIM, light micrographs, and SEM images. Preliminary data suggest that nuclear microprobe techniques may be useful in elucidating element absorption and transport mechanisms in lichens. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. Brigham Young Univ, Dept Bot & Range Sci, Provo, UT 84602 USA. Brigham Young Univ, Dept Phys & Astron, Provo, UT 84602 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Mangelson, NF (reprint author), Brigham Young Univ, Dept Chem & Biochem, C100 BNSN, Provo, UT 84602 USA. NR 11 TC 18 Z9 18 U1 2 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 APR PY 1999 VL 150 IS 1-4 BP 248 EP 253 DI 10.1016/S0168-583X(98)00919-7 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 192AZ UT WOS:000080056500042 ER PT J AU Perl, ML AF Perl, ML TI A perspective on Tau physics SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International Workshop on Tau Lepton Physics CY SEP 14-17, 1998 CL SANTANDER, SPAIN ID NEUTRINO MASS; CP VIOLATION; UPPER LIMIT; DECAYS AB It will soon be the twenty fifth anniversary of the discovery of the tau lepton. It has been an amazing twenty five years for tau physics and for the strong interaction physics that can be deduced from studies of tau decays. The discovery of the tau was based on the elucidation of the nature of about one hundred tan pairs. At this Fifth International Workshop on Tau Lepton Physics new results in tau physics are based on hundreds of thousands or even millions of tau pairs. In the next two decades we will see the data on tau pairs increase by at least a factor of ten. The theoretical work and theoretical understanding of tau physics and tau neutrino physics has also expanded enormously, and this theory will continue to grow in its reach and its depth. Given the vastness of this field and the recognition that there is always great uncertainty in predicting future directions and accomplishments in a scientific field; any perspective of the future of a scientific field is substantially dependent on the author's opinions and guesses. I have limited this talk to seven topics: tau research facilities in the next decades, searching for unexpected tau decay modes, searching for additional tau decay mechanisms, radiative tau decays, tau decay modes of the W, B, and D, searching for CP violation in tau decay, and rethinking the Tau-Charm factory. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94306 USA. RP Perl, ML (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94306 USA. NR 30 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 APR PY 1999 VL 76 BP 3 EP 19 DI 10.1016/S0920-5632(99)80001-2 PG 17 WC Physics, Particles & Fields SC Physics GA 207XV UT WOS:000080961800002 ER PT J AU Protopopescu, S AF Protopopescu, S CA CDF DO Collaborations TI W -> tau nu at the Tevatron SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International Workshop on Tau Lepton Physics CY SEP 14-17, 1998 CL SANTANDER, SPAIN ID ROOT-S=1.8 TEV; P(P)OVER-BAR COLLISIONS; BOSON AB We present results from the CDF and D empty set detectors on the production of W-bosons decaying to tau nu(tau) at the FNAL Tevatron from data taken between 1992 and 1996. From CDF comes the first observation of W charge asymmetry in W --> tau nu final states, and from D empty set a new measurement of g(tau)(W)/g(e)(W), 1.003 +/- 0.032. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Protopopescu, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 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 APR PY 1999 VL 76 BP 91 EP 97 DI 10.1016/S0920-5632(99)00396-5 PG 7 WC Physics, Particles & Fields SC Physics GA 207XV UT WOS:000080961800009 ER PT J AU Bartoldus, R AF Bartoldus, R TI Measurement of the Michel parameters in leptonic tau decays using the OPAL detector at LEP SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International Workshop on Tau Lepton Physics CY SEP 14-17, 1998 CL SANTANDER, SPAIN AB A measurement of the Michel parameters in tau decays is presented [1] which involves a novel method to fit the energy spectra and energy-energy correlations of the charged decay leptons from tau-pair events produced in e(+)e(-) collisions close to root s = m(Z0). The parameters rho(l), xi(l), (xi delta)(l) (with l = e, mu) and eta(mu) have been extracted from a global likelihood fit of Monte Carlo generated events to the data set recorded with the OPAL detector in the years 1990-1995. If e-mu universality is assumed and inferring the tau polarization from neutral current data, the measured Michel parameters are rho = 0.781 +/- 0.028 +/- 0.018, xi = 0.98 +/- 0.22 +/- 0.10, xi delta = 0.65 +/- 0.14 +/- 0.07 and eta = 0.027 +/- 0.055 +/- 0.005, where the value of eta has been constrained using the published OPAL measurements of the leptonic branching ratios and the tau lifetime. Limits on the masses of new intermediate bosons and on non-standard couplings are obtained. It is explained how such limits can be derived from an investigation of the Michel parameter space. C1 Univ Bonn, Inst Phys, D-53115 Bonn, Germany. RP Bartoldus, R (reprint author), Stanford Linear Accelerator Ctr, Univ Iowa, POB 4349,MS 59, Stanford, CA 94309 USA. NR 16 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 APR PY 1999 VL 76 BP 147 EP 157 DI 10.1016/S0920-5632(99)00450-8 PG 11 WC Physics, Particles & Fields SC Physics GA 207XV UT WOS:000080961800016 ER PT J AU Czarnecki, A Marciano, WJ AF Czarnecki, A Marciano, WJ TI Lepton anomalous magnetic moments - a theory update SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International Workshop on Tau Lepton Physics CY SEP 14-17, 1998 CL SANTANDER, SPAIN ID VACUUM POLARIZATION INSERTIONS; MUON G-2; ELECTROWEAK CORRECTIONS; HADRONIC CONTRIBUTIONS; RENORMALIZATION-GROUP; TAU-LEPTON; CONSTRAINTS; GRAPHS; (G-2)(MU); MODELS AB Standard Model contributions to the electron, muon, and tan lepton anomalous magnetic moments, al (g(l) - 2)/2, are reviewed and updated. The fine structure constant is obtained from the electron g(e) - 2 and used to refine the QED contribution to the muon g(mu) - 2. Recent advances in electroweak and hadronic effects on g(mu) - 2 are summarized. Examples of "New Physics" probed by the a(mu) Brookhaven experiment E821 are outlined. The prediction for a(tau) is also given. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Czarnecki, A (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 67 TC 95 Z9 95 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 APR PY 1999 VL 76 BP 245 EP 252 DI 10.1016/S0920-5632(99)00474-0 PG 8 WC Physics, Particles & Fields SC Physics GA 207XV UT WOS:000080961800028 ER PT J AU Perdekamp, MG Benedict, E Brown, DH Carey, RM Earle, W Efstathiadis, E Hare, MF Hazen, ES Hughes, BJ Krienen, F Logashenko, I Miller, JP Monich, V Ouyang, J Rind, O Roberts, BL Sulak, LR Trofimov, A Varner, G Worstell, WA Benante, J Brown, HN Bunce, G Cullen, J Danby, GT Geller, J Hseuh, H Jackson, JW Jia, L Kochis, S Larsen, R Lee, YY Mapes, M Meng, W Morse, WM Pai, C Pearson, C Polk, I Prigl, R Rankowitz, S Sandberg, J Semertzidis, YK Shutt, R Snydstrup, L Soukas, A Stillman, A Tanaka, M Tallerico, T Toldo, F von Lintig, D Warbuton, D Woodle, K Chertovskikh, A Druzhinin, VP Fedotovich, GV Grigorev, DN Golubev, VB Khazin, BI Maskimov, A Merzliakov, Y Ryskulov, ON Serednyakov, S Shatunov, YM Solodov, E Orlov, Y Winn, D Gerhaeuser, J Grossmann, A Jungmann, K von Walter, P Putlitz, GZ Bunker, B Debevec, PT Deninger, W Hertzog, DW Jones, T Poly, C Sedykh, S Urner, D Haeberlen, U Endo, K Hirabayashi, H Kurokawa, S Yamamoto, A Green, MA Cushman, P Duong, L Giron, S Kindem, J McNabb, R Miller, D Timmermans, C Zimmerman, D Mizumachi, Y Iwasaki, M Ahn, HE Deng, H Dhawan, SK Disco, A Farley, FJM Fei, X Hughes, VW Kawall, D Pretz, J Redin, SI AF Perdekamp, MG Benedict, E Brown, DH Carey, RM Earle, W Efstathiadis, E Hare, MF Hazen, ES Hughes, BJ Krienen, F Logashenko, I Miller, JP Monich, V Ouyang, J Rind, O Roberts, BL Sulak, LR Trofimov, A Varner, G Worstell, WA Benante, J Brown, HN Bunce, G Cullen, J Danby, GT Geller, J Hseuh, H Jackson, JW Jia, L Kochis, S Larsen, R Lee, YY Mapes, M Meng, W Morse, WM Pai, C Pearson, C Polk, I Prigl, R Rankowitz, S Sandberg, J Semertzidis, YK Shutt, R Snydstrup, L Soukas, A Stillman, A Tanaka, M Tallerico, T Toldo, F von Lintig, D Warbuton, D Woodle, K Chertovskikh, A Druzhinin, VP Fedotovich, GV Grigorev, DN Golubev, VB Khazin, BI Maskimov, A Merzliakov, Y Ryskulov, ON Serednyakov, S Shatunov, YM Solodov, E Orlov, Y Winn, D Gerhaeuser, J Grossmann, A Jungmann, K von Walter, P Putlitz, GZ Bunker, B Debevec, PT Deninger, W Hertzog, DW Jones, T Poly, C Sedykh, S Urner, D Haeberlen, U Endo, K Hirabayashi, H Kurokawa, S Yamamoto, A Green, MA Cushman, P Duong, L Giron, S Kindem, J McNabb, R Miller, D Timmermans, C Zimmerman, D Mizumachi, Y Iwasaki, M Ahn, HE Deng, H Dhawan, SK Disco, A Farley, FJM Fei, X Hughes, VW Kawall, D Pretz, J Redin, SI TI Status of the g-2 experiment at BNL SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International Workshop on Tau Lepton Physics CY SEP 14-17, 1998 CL SANTANDER, SPAIN ID ANOMALOUS MAGNETIC-MOMENT; DIPOLE-MOMENT; MUON AB The muon g-2 experiment at Brookhaven has successfully completed two exploratory runs using pion injection and direct muon injection for checkout and initial data taking. The main components of the experiment, which include the pion beam line, the superconducting storage ring and inflector magnets, the muon kicker and the lead-scintillating fiber calorimeters have been satisfactorily commissioned. First results on the anomalous magnetic moment of the positive muon from pion injection are in good agreement with previous experimental results for a(mu+) and a(mu-) from CERN and of comparable accuracy (13 ppm). Analysis of the 1998 muon injection run is in progress and expected to improve the precision to about 4 ppm. A first production run is scheduled for January 1999 with the goal of reaching the 1 ppm error level. C1 Yale Univ, Dept Phys, New Haven, CT 06511 USA. Tokyo Inst Technol, Tokyo 152, Japan. Sci Univ Tokyo, Tokyo 162, Japan. Univ Minnesota, Dept Phys, Minneapolis, MN 55455 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. KEK, High Energy Accelerator Res Org, Ibaraki, Osaka 3050801, Japan. Max Planck Inst Med Forsch, D-69120 Heidelberg, Germany. Univ Illinois, Dept Phys, Champaign, IL 61820 USA. Univ Heidelberg, Inst Phys, D-69120 Heidelberg, Germany. Fairfield Univ, Fairfield, CT 06430 USA. Cornell Univ, Newman Lab, Ithaca, NY 14853 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. Brookhaven Natl Lab, Upton, NY 11973 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Univ Mainz, Inst Kernphys, D-55099 Mainz, Germany. RP Perdekamp, MG (reprint author), Yale Univ, Dept Phys, New Haven, CT 06511 USA. RI Jungmann, Klaus/A-7142-2010; jungmann, klaus/H-1581-2013; Semertzidis, Yannis K./N-1002-2013; Logashenko, Ivan/A-3872-2014; Iwasaki, Masahiko/M-8433-2014; OI jungmann, klaus/0000-0003-0571-4072; Iwasaki, Masahiko/0000-0002-3460-9469; Kemp-Benedict, Eric/0000-0001-5794-7172 NR 17 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 APR PY 1999 VL 76 BP 253 EP 260 DI 10.1016/S0920-5632(99)00477-6 PG 8 WC Physics, Particles & Fields SC Physics GA 207XV UT WOS:000080961800029 ER PT J AU Ramberg, EJ AF Ramberg, EJ TI Radiative hyperon decays at KTeV SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 3rd International Conference on Hyperons, Charm and Beauty Hadrons CY JUN 30-JUL 03, 1998 CL GENOA, ITALY ID BRANCHING RATIO; ASYMMETRY PARAMETER AB Experiment 799 at Fermilab was the rare decay run of the KTeV apparatus. Besides collecting a large number of neutral kaon decays, the apparatus was used to trigger for rare decays of neutral hyperons. In this paper we present the status of our measurements of the hyperon radiative decays Xi(o) --> Sigma(o)gamma, Xi(o) --> Lambda gamma, Lambda --> p pi(-)gamma, as well as evidence for the first observation of Xi(o) --> Lambda pi(o)gamma and Sigma(o) --> Lambda e(+)e(-). C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Ramberg, EJ (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 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 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 1999 VL 75B BP 41 EP 44 DI 10.1016/S0920-5632(99)00320-5 PG 4 WC Physics, Particles & Fields SC Physics GA 206ZK UT WOS:000080910700011 ER PT J AU Serbo, VV AF Serbo, VV TI Electroweak measurements with heavy quarks at SLD SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 3rd International Conference on Hyperons, Charm and Beauty Hadrons CY JUN 30-JUL 03, 1998 CL GENOA, ITALY ID VERTEX AB The SLD detector collects data at the Z(0) resonance using e(+)e(-) colliding beams of SLC. Polarized electron beams and small SLC interaction region together with the unique CCD vertex detector provide an outstanding opportunity for precision electroweak test of the standard model, especially in the heavy quark sector. Improved measurements of heavy quark electroweak parameters, including A(b), A(c), R-b, and R-c are presented. Measurements are based on approximately 400k hadronic Z(0) events, including data from the most recent 1997-98 SLC run. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Serbo, VV (reprint author), Stanford Linear Accelerator Ctr, MS 61,POB 4349, Stanford, CA 94309 USA. NR 11 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 APR PY 1999 VL 75B BP 236 EP 240 DI 10.1016/S0920-5632(99)00358-8 PG 5 WC Physics, Particles & Fields SC Physics GA 206ZK UT WOS:000080910700049 ER PT J AU Dukes, C AF Dukes, C TI Search for CP violation in Xi and Lambda hyperon decays: Status of the HyperC(P) experiment SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 3rd International Conference on Hyperons, Charm and Beauty Hadrons CY JUN 30-JUL 03, 1998 CL GENOA, ITALY ID NONCONSERVATION; INVARIANCE; GEV/C AB HyperC(P) (E871), a Fermilab experiment searching for CP violation in Xi and Lambda hyperon decays, finished its first data taking run at the end of 1997, and accumulated over one billion Xi(-) and <(Xi)over bar>(+) decays. A sensitivity of approximately 2 x 10(-4) in A(Xi Lambda) = (alpha(Xi)alpha(Lambda) - alpha(Xi)alpha(<(Lambda)over bar>))/(alpha(Xi)alpha(Lambda) + alpha(Xi)alpha(<(Lambda)over bar>)) is expected. A non-zero value of A(Xi Lambda) Would be unambiguous evidence for direct CP violation. A brief review of CP violation in hyperon decays is given, the HyperC(P) spectrometer is described, and the status of the analysis and future prospects are discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. RP Dukes, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 19 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 APR PY 1999 VL 75B BP 281 EP 287 DI 10.1016/S0920-5632(99)00365-5 PG 7 WC Physics, Particles & Fields SC Physics GA 206ZK UT WOS:000080910700056 ER PT J AU Olsson, MG Allen, TJ Veseli, S AF Olsson, MG Allen, TJ Veseli, S TI Flux tube vibrations and the excited glue spectroscopy SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 3rd International Conference on Hyperons, Charm and Beauty Hadrons CY JUN 30-JUL 03, 1998 CL GENOA, ITALY AB As a step toward a fundamental understanding of hybrid states we demonstrate the close relationship between the relativistic string and lattice simulation results for excited glue states with two fixed color sources. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Olsson, MG (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 1999 VL 75B BP 299 EP 301 DI 10.1016/S0920-5632(99)00368-0 PG 3 WC Physics, Particles & Fields SC Physics GA 206ZK UT WOS:000080910700059 ER PT J AU Butler, JN AF Butler, JN TI Status of BTeV - A dedicated B physics experiment at the Fermilab Tevatron Collider SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 3rd International Conference on Hyperons, Charm and Beauty Hadrons CY JUN 30-JUL 03, 1998 CL GENOA, ITALY ID PHASE-GAMMA AB BTeV is a program whose long term goal is to carry out precision studies of CP violation, mixing, and rare decays of bottom and charmed quarks in the forward direction at the Fermilab Tevatron Collider. It is planned for the new interaction region, CO, currently being constructed. We describe the techniques, physics reach, and status of BTeV. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Butler, JN (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 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 APR PY 1999 VL 75B BP 307 EP 314 DI 10.1016/S0920-5632(99)00370-9 PG 8 WC Physics, Particles & Fields SC Physics GA 206ZK UT WOS:000080910700061 ER PT J AU Pryke, C Voyvodic, L AF Pryke, C Voyvodic, L TI Some effects of first proton-air interactions on development of giant air showers SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 10th International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI) CY JUL 12-17, 1998 CL GRAN SASSO LAB, ASSERGI, ITALY SP Int Union Pure & Appl Phys, Cosmic Ray Commiss & Emulsion Chamber Comm HO GRAN SASSO LAB AB Air shower simulations have been studied for dependence on features of the initial proton-air collisions at 10(19) eV. Comparisons are made between results with Sibyll and QGSjet hadronic interaction event generators. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. RP Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 EI 1873-3832 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 1999 VL 75A BP 365 EP 367 DI 10.1016/S0920-5632(99)00293-5 PG 3 WC Physics, Particles & Fields SC Physics GA 205WK UT WOS:000080843400087 ER PT J AU Wischnewski, R Andres, E Askebjer, P Barwick, S Bay, R Bergstrom, L Biron, A Booth, J Botner, O Bouchta, A Carius, S Carlson, M Chinowsky, W Chirkin, D Cowen, D Costa, C Dalberg, E Deyoung, T Edsjo, J Ekstrom, P Goobar, A Gray, L Hallgren, A Halzen, F Hardtke, R He, Y Hill, G Hulth, P Hundertmark, S Jacobsen, J Kandhadai, V Karle, A Kim, J Leich, H Leuthold, M Lindahl, P Liss, T Liubarsky, I Loaiza, P Lowder, D Marciniewski, P Miller, T Miocinovic, P Mock, P Morse, R Newcomer, M Niessen, P Nygren, D de los Heros, CP Porrata, R Price, P Przybylski, G Rhode, W Richter, S Rodriguez, J Romenesko, P Ross, D Rubinstein, H Schmidt, T Schneider, E Schwarz, R Schwendicke, U Smoot, G Solarz, M Sorin, V Spiering, C Steffen, P Stokstad, R Streicher, O Thollander, L Thon, T Tilav, S Walck, C Wiebusch, C Woschnagg, K Wu, W Yodh, G Young, S AF Wischnewski, R Andres, E Askebjer, P Barwick, S Bay, R Bergstrom, L Biron, A Booth, J Botner, O Bouchta, A Carius, S Carlson, M Chinowsky, W Chirkin, D Cowen, D Costa, C Dalberg, E Deyoung, T Edsjo, J Ekstrom, P Goobar, A Gray, L Hallgren, A Halzen, F Hardtke, R He, Y Hill, G Hulth, P Hundertmark, S Jacobsen, J Kandhadai, V Karle, A Kim, J Leich, H Leuthold, M Lindahl, P Liss, T Liubarsky, I Loaiza, P Lowder, D Marciniewski, P Miller, T Miocinovic, P Mock, P Morse, R Newcomer, M Niessen, P Nygren, D de los Heros, CP Porrata, R Price, P Przybylski, G Rhode, W Richter, S Rodriguez, J Romenesko, P Ross, D Rubinstein, H Schmidt, T Schneider, E Schwarz, R Schwendicke, U Smoot, G Solarz, M Sorin, V Spiering, C Steffen, P Stokstad, R Streicher, O Thollander, L Thon, T Tilav, S Walck, C Wiebusch, C Woschnagg, K Wu, W Yodh, G Young, S TI The AMANDA Neutrino Detector SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 10th International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI) CY JUL 12-17, 1998 CL GRAN SASSO LAB, ASSERGI, ITALY SP Int Union Pure & Appl Phys, Cosmic Ray Commiss & Emulsion Chamber Comm HO GRAN SASSO LAB AB The first stage of the AMANDA High Energy Neutrino Detector at the South Pole, the 302 PMT array AMANDA-B with an expected effective area for TeV neutrinos of similar to 10(4) m(2), has been taking data since 1997. Progress with calibration, investigation of ice properties, as well as muon and neutrino data analysis are described. The next stage 20-string detector AMANDA-II with similar to 800 PMTs will be completed in spring 2000. C1 DESY, Inst High Energy Phys, Zeuthen, Germany. Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden. Univ Calif Irvine, Dept Phys, Irvine, CA 92717 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Uppsala, Uppsala, Sweden. Kalmar Univ, Dept Phys, Kalmar, Sweden. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Lawrence Berkeley Lab, Berkeley, CA USA. Univ Penn, Dept Phys, Philadelphia, PA 19104 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Wischnewski, R (reprint author), DESY, Inst High Energy Phys, Zeuthen, Germany. RI Wiebusch, Christopher/G-6490-2012; Hundertmark, Stephan/A-6592-2010; Botner, Olga/A-9110-2013; Hallgren, Allan/A-8963-2013; Loaiza, Pia/D-5861-2013; OI Wiebusch, Christopher/0000-0002-6418-3008; Streicher, Ole/0000-0001-7751-1843 NR 9 TC 4 Z9 4 U1 0 U2 2 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 APR PY 1999 VL 75A BP 412 EP 414 DI 10.1016/S0920-5632(99)00309-6 PG 3 WC Physics, Particles & Fields SC Physics GA 205WK UT WOS:000080843400103 ER PT J AU Daling, PM Graham, TM AF Daling, PM Graham, TM TI Hand calculation of safe separation distances between natural-gas pipelines and boilers and nuclear facilities in the Hanford Site 300 Area SO NUCLEAR TECHNOLOGY LA English DT Article DE separation distance; fires; explosions AB The U.S. Department of Energy has undertaken a project to reduce energy expenditures and improve energy system reliability in the 300 Area of the Hanford Site near Richland, Washington. This project replaced the centralized hearing system with heating units for individual buildings or groups of buildings, constructed a new natural-gas distribution system to provide a fuel source for many of these units, and constructed a central control building to operate and maintain the system. The individual heating units include steam boilers that are housed in individual annex buildings located in the vicinity of a number of nuclear facilities operated by the Pacific Northwest National Laboratory (PNNL). The described analysis develops the basis for siting the package boilers and natural-gas distribution system used to supply steam to PNNL's 300 Area nuclear facilities. Minimum separation distances that would eliminate or reduce the risks of accidental dispersal of radioactive and hazardous materials in nearby nuclear facilities were calculated based on the effects of four potential fire and explosion (detonation) scenarios involving the bailer and natural-gas distribution system. These minimum separation distances were-used to support airing decisions for the boilers and natural-gas pipelines. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Daling, PM (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD APR PY 1999 VL 126 IS 1 BP 62 EP 74 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 181KG UT WOS:000079440100005 ER PT J AU Rest, J Hofman, GL AF Rest, J Hofman, GL TI Dart model for irradiation-induced swelling of uranium silicide dispersion fuel elements SO NUCLEAR TECHNOLOGY LA English DT Article DE irradiation-induced swelling; dispersion fuel; modeling irradiation behavior AB Models for the interaction of-uranium silicide dispersion fuels with an aluminum matrix for the resultant reaction product swelling, and for the calculation of the stress gradient within the fuel particles are described within the context of DART fission-gas-induced swelling models. The effects of an aluminide shell on fuel particle swelling are evaluated. Validation of the model is demonstrated by comparing DART calculations with irradiation data for the swelling of U3SiAl-Al and U3Si2-Al in variously designed dispersion fuel elements. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Rest, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM jrest@anl.gov NR 18 TC 6 Z9 7 U1 6 U2 12 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD APR PY 1999 VL 126 IS 1 BP 88 EP 101 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 181KG UT WOS:000079440100007 ER PT J AU Bennett, RG Christian, JD Petti, DA Terry, WK Grover, SB AF Bennett, RG Christian, JD Petti, DA Terry, WK Grover, SB TI A system of Tc-99m production based on distributed electron accelerators and thermal separation SO NUCLEAR TECHNOLOGY LA English DT Article DE Tc-99m production system; electron accelerator applications; Tc-99m thermal separation ID GENERATORS AB A system has been developed for the production of Tc-99m based on distributed electron accelerators and thermal separation. The radioactive decay parent of Tc-99m, Mo-99, is produced from Mo-100 by a photoneutron reaction. Two alternative thermal separation processes have been developed to extract Tc-99m. Experiments have been performed to verify the technical feasibility of the production and assess the efficiency of the extraction processes. A system based on this technology enables the economical supply of Tc-99m for a large nuclear pharmacy. Twenty such production centers distributed near major metropolitan areas could produce the entire U.S. supply of Tc-99m at a cost less than the current subsidized price. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Bennett, RG (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 44 TC 21 Z9 21 U1 0 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD APR PY 1999 VL 126 IS 1 BP 102 EP 121 PG 20 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 181KG UT WOS:000079440100008 ER PT J AU Stevens, PW Henry, MR Kelso, DM AF Stevens, PW Henry, MR Kelso, DM TI DNA hybridization on microparticles: determining capture-probe density and equilibrium dissociation constants SO NUCLEIC ACIDS RESEARCH LA English DT Article ID OLIGONUCLEOTIDE ARRAYS; FLUORESCENCE ANALYSIS; DUPLEX STABILITY; SUPPORTS; PURIFICATION; MISMATCHES; PARAMETERS; PARTICLES; NMR AB Many DNA-probe assays utilize oligonucleotide-coated microparticles for capture of complementary nucleic acids from solution. During development of these assays, as well as in other particle-based nucleic acid applications, it is useful to know both the amount of duplex formation expected under various experimental conditions and the coating density of the capture oligonucleotide on the particle surface. We examined the simplest form of a DNA-probe microparticle assay: hybridization of a particle-bound capture oligonucleotide to its solution-phase complement. Fluorescein-labeled solution-phase oligonucleotide was hybridized to varying amounts of particles, and the amount of labeled oligonucleotide remaining in solution at equilibrium was measured. We present a simple two-state, all-or-none model for bimolecular hybridization of non-self-complementary sequences that can be used to calculate the equilibrium dissociation constant (Kd) from hybridization data. With experimental conditions where both the Kd value and the concentration of capture probe in the reaction are small relative to the concentration of labeled complementary oligonucleotide in the reaction, density of the capture probe on the particle's surface can also be determined. Kd values for particle-based hybridization were different from those obtained from solution-phase thermodynamic parameters. At higher temperatures, hybridization on particles was more efficient than hybridization in solution. C1 Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Biomed Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. RP Stevens, PW (reprint author), Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Biomed Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA. EM pwilkins@nwu.edu RI Kelso, David/B-7619-2009; Kelso, David/F-5622-2013 NR 37 TC 51 Z9 51 U1 1 U2 16 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 EI 1362-4962 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 1 PY 1999 VL 27 IS 7 BP 1719 EP 1727 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 182NG UT WOS:000079504600019 ER PT J AU Seward, JP AF Seward, JP TI Occupational allergy to animals SO OCCUPATIONAL MEDICINE-STATE OF THE ART REVIEWS LA English DT Review ID GYPSY-MOTH-CATERPILLAR; LABORATORY-ANIMALS; RESPIRATORY ALLERGY; CONTACT URTICARIA; URINARY PROTEINS; EPIDEMIOLOGIC EVALUATION; METHACHOLINE CHALLENGE; AIRWAY RESPONSIVENESS; UNIVERSITY EMPLOYEES; MOUSE ALLERGENS C1 Univ Calif Lawrence Livermore Natl Lab, Hlth Serv Dept L723, Livermore, CA 94551 USA. RP Seward, JP (reprint author), Univ Calif Lawrence Livermore Natl Lab, Hlth Serv Dept L723, Livermore, CA 94551 USA. NR 130 TC 26 Z9 28 U1 0 U2 1 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 USA SN 0885-114X J9 OCCUP MED JI Occup. Med.-State Art Rev. PD APR-JUN PY 1999 VL 14 IS 2 BP 285 EP 303 PG 19 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 184TF UT WOS:000079629000008 PM 10329906 ER PT J AU Garbe, J Wong, M Wigington, D Yaswen, P Stampfer, MR AF Garbe, J Wong, M Wigington, D Yaswen, P Stampfer, MR TI Viral oncogenes accelerate conversion to immortality of cultured conditionally immortal human mammary epithelial cells SO ONCOGENE LA English DT Article DE immortalization; telomerase; p53; TGF beta; human papillomavirus; SV40T ID HUMAN PAPILLOMAVIRUS TYPE-16; LARGE T-ANTIGEN; TELOMERASE ACTIVITY; HUMAN FIBROBLASTS; BREAST-CANCER; P16 INACTIVATION; TUMOR-ANTIGEN; P53 GENE; E6; PROTEIN AB Our recent studies on the process of immortalization of cultured human mammary epithelial cells (HMEC) have uncovered a previously undescribed, apparently epigenetic step, termed conversion. When first isolated, clonally derived HMEC lines of indefinite lifespan showed little or no telomerase activity or ability to maintain growth in the presence of TGF beta. Cell populations whose mean terminal restriction fragment length had declined to <3 kb also exhibited slow heterogeneous growth, and contained many non-proliferative cells. With continued passage, these conditionally immortal cell populations very gradually converted to a fully immortal phenotype of good growth+/-TGF beta, expression of high levels of telomerase activity, and stabilization of telomere length. We now show that exposure of the early passage conditionally immortal 184A1 HMEC line to the viral oncogenes human papillomavirus type 16 (HPV16)-E6, -E7, or SV40T, results in either immediate (E6) or rapid (E7; SV40T) conversion of these telomerase negative, TGF beta sensitive conditionally immortal cells to the fully immortal phenotype. Unlike conditional immortal 184A1, the HPV16-E7 and SV40T exposed cells were able to maintain growth in TGF beta prior to expression of high levels of telomerase activity. A mutated HPV16-E6 oncogene, unable to inactivate p53, was still capable of rapidly converting conditional immortal 184A1. Our studies provide further evidence that the transforming potential of these viral oncogenes may involve activities beyond their inactivation of p53 and pRB functions. These additional activities may greatly accelerate a step in HMEC immortal transformation, conversion, that would be rate-limiting in the absence of viral oncogene exposure. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Stampfer, MR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Bldg 934, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-24844] NR 53 TC 37 Z9 38 U1 0 U2 1 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD APR 1 PY 1999 VL 18 IS 13 BP 2169 EP 2180 DI 10.1038/sj.onc.1202523 PG 12 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 182YE UT WOS:000079525100001 PM 10327063 ER PT J AU Chu, AS Butler, MA AF Chu, AS Butler, MA TI Laser surface profiler SO OPTICS LETTERS LA English DT Article ID PROFILOMETER; INSTRUMENTS; MICROSCOPY; METROLOGY AB By accurate measurement of the angle of reflection of a laser beam that is incident upon a reflective surface with a position-sensitive detector, changes in the surface-normal direction (the slope or the derivative of the surface) can be determined directly. An instrument has been built that makes repeated measurements over the surface and uses the collected data to produce a gray-scale image of the slope. The resolution of this system for detecting changes in the surface-normal direction is found to be better than 0.01 degrees. By focusing of the laser beam to achieve a lateral resolution of 5 mu m, the resolvable surface-height change owing to a variation in slope is estimated to be <1 nm. (C) 1999 Optical Society of America. C1 Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Microsensor Res & Dev Dept, POB 5800, Albuquerque, NM 87185 USA. EM achu@sandia.gov NR 10 TC 0 Z9 0 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 EI 1539-4794 J9 OPT LETT JI Opt. Lett. PD APR 1 PY 1999 VL 24 IS 7 BP 457 EP 459 DI 10.1364/OL.24.000457 PG 3 WC Optics SC Optics GA 182TF UT WOS:000079513700011 PM 18071538 ER PT J AU Nicholson, JW Omenetto, FG Funk, DJ Taylor, AJ AF Nicholson, JW Omenetto, FG Funk, DJ Taylor, AJ TI Evolving FROGS: phase retrieval from frequency-resolved optical gating measurements by use of genetic algorithms SO OPTICS LETTERS LA English DT Article ID PULSES AB We present a new technique based on genetic algorithms for retrieving the electric field and the phase of ultrashort pulses from frequency-resolved optical gating (FROG) traces. We have successfully applied a very basic genetic algorithm to the two most common beam geometries: polarization gate and second-harmonic generation (SHG). In the case of SHG FROG, the genetic algorithm returns a lower error than the standard iterative composite algorithm. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nicholson, JW (reprint author), Univ New Mexico, Dept Phys & Astron, 800 Yale Blvd NE, Albuquerque, NM 87131 USA. NR 11 TC 16 Z9 17 U1 0 U2 5 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 APR 1 PY 1999 VL 24 IS 7 BP 490 EP 492 DI 10.1364/OL.24.000490 PG 3 WC Optics SC Optics GA 182TF UT WOS:000079513700022 PM 18071549 ER PT J AU Clune, TC Elliott, JR Miesch, MS Toomre, J Glatzmaier, GA AF Clune, TC Elliott, JR Miesch, MS Toomre, J Glatzmaier, GA TI Computational aspects of a code to study rotating turbulent convection in spherical shells SO PARALLEL COMPUTING LA English DT Article DE convection; anelastic spherical harmonic code ID COMPRESSIBLE CONVECTION; NUMERICAL SIMULATIONS; DYNAMICS; FLUID; ZONE AB The coupling of highly turbulent convection with rotation within a full spherical shell geometry, such as in the solar convection zone, can be studied with the new anelastic spherical harmonic (ASH) code developed to exploit massively parallel architectures. Inter-processor transposes are used to ensure data locality in spectral transforms, a sophisticated load balancing algorithm is implemented and the Legendre transforms, which dominate the workload for large problems, are highly optimized by exploiting the features of cache memory and instruction pipelines. As a result, the ASH code achieves around 120 Mflop/s per node on the Gray T3E and scales nearly linearly for adequately large problem sizes. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Calif Los Alamos Natl Lab, IGPP, Los Alamos, NM 87545 USA. RP Elliott, JR (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. RI Miesch, Mark/B-1104-2008; OI Miesch, Mark/0000-0003-1976-0811 NR 17 TC 134 Z9 134 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 J9 PARALLEL COMPUT JI Parallel Comput. PD APR PY 1999 VL 25 IS 4 BP 361 EP 380 DI 10.1016/S0167-8191(99)00009-5 PG 20 WC Computer Science, Theory & Methods SC Computer Science GA 195FU UT WOS:000080240600002 ER PT J AU Bayir, H Parker, R Praisman, L Dunn, T Dunn, J Viola, MV AF Bayir, H Parker, R Praisman, L Dunn, T Dunn, J Viola, MV TI Structure of the thrombopoietin receptor in the thrombocytopenia with absent radius (TAR) syndrome SO PEDIATRIC RESEARCH LA English DT Meeting Abstract C1 SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU INT PEDIATRIC RESEARCH FOUNDATION, INC PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 USA SN 0031-3998 J9 PEDIATR RES JI Pediatr. Res. PD APR PY 1999 VL 45 IS 4 MA 837 BP 144A EP 144A DI 10.1203/00006450-199904020-00854 PN 2 PG 1 WC Pediatrics SC Pediatrics GA 182AQ UT WOS:000079476700838 ER PT J AU Nellis, WJ AF Nellis, WJ TI Metastable solid metallic hydrogen SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID FLUID MOLECULAR-HYDROGEN; ELECTRICAL-CONDUCTIVITY; MEGABAR PRESSURES; DENSE HYDROGEN; TRANSITION; EQUATION; JUPITER; STATE; GPA AB Hydrogen reaches the mimimum electrical conductivity of a metal at 140 GPa (1.4 Mbar), 0.6 g cm(-3) (ninefold compression of initial liquid-H(2) density) and 3000 K in the fluid phase. The quest for metallic hydrogen over the past 100 years is reviewed briefly. Possible scientific and technological uses of metastable solid metallic hydrogen (MSMH) are speculated upon in the unlikely event that the metallic fluid can be quenched to MSMH at ambient pressure and temperature: a quantum, mostly diatomic, metallic solid with novel physical properties, including room-temperature superconductivity; a very light-weight structural material; a fuel, propellant, or explosive, depending on the rate of release of stored energy; a dense fuel for higher energy yields in inertial confinement fusion; and an aid in the synthesis of novel hard materials. Some of the formidable difficulties to synthesize MSMH are discussed. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nellis, WJ (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 35 TC 19 Z9 19 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD APR PY 1999 VL 79 IS 4 BP 655 EP 661 PG 7 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 182VX UT WOS:000079519800007 ER PT J AU Pinder, JE McLeod, KW AF Pinder, JE McLeod, KW TI Indications of relative drought stress in longleaf pine from thematic mapper data SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID LEAF WATER-CONTENT; SPECTRAL REFLECTANCE; MULTISPECTRAL DATA; LANDSAT TM; LEAVES; MIDDLE; SYSTEM AB Multitemporal Thematic Mapper data indicated that the ratios of reflectances of band 5 to band 4 increased as longleaf pine were subjected to a prolonged drought that began in the fall of 1989 and continued through the fall of 1990. Mean ratios increased from 0.42 preceding the drought to 0.55 during the drought, but the amount of the increase varied from 0.05 to 0.25 among forest stands. Ratios returned to predrought levels once the drought was broken. Tree ring widths in 1990 were significantly smaller than were those for years of average rainfall before the drought, and residual drought stress effects contributed to smaller ring widths in subsequent years. The degree of reduction in ring widths was correlated to the degree of increase in the ratio of band 5 to band 4. The greatest size reductions in ring widths occurred in those stands with the greatest increase in band ratios. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Pinder, JE (reprint author), Univ Georgia, Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 48 TC 9 Z9 9 U1 0 U2 3 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD APR PY 1999 VL 65 IS 4 BP 495 EP 501 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 181EU UT WOS:000079428800010 ER PT J AU Kobayashi, H Hatano, N Miyashita, S AF Kobayashi, H Hatano, N Miyashita, S TI Non-adiabatic transition in spin-boson model and generalization of the Landau-Zener formula SO PHYSICA A LA English DT Article DE Landau-Zener formula; quantum dynamics; spin-boson model; exponential product formula ID MAGNETIC PARTICLES; QUANTUM AB Non-adiabatic transitions are studied in a spin-boson model with multiple scattering points. In order to generalize the Landau-Zener formula, which describes the case of a single scattering point, we define an "effective gap" for a set of scattering points. The generalized formula agrees very well with numerical results of the non-adiabatic dynamics, which we obtained by a direct numerical method. This will make the Landau-Zener formula yet more useful in analyzing experimental data of magnetic-moment inversion. (C) 1999 Elsevier Science B.V, All rights reserved. C1 Univ Tokyo, Grad Sch Sci, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Osaka Univ, Fac Sci, Dept Earth & Space Sci, Toyonaka, Osaka 5600043, Japan. RP Kobayashi, H (reprint author), Care Of Kuniba A, Univ Tokyo, Inst Phys, Meguro Ku, Tokyo 1538902, Japan. RI Hatano, Naomichi/K-8176-2012; MIYASHITA, SEIJI/G-5079-2014 OI Hatano, Naomichi/0000-0003-0277-1856; NR 12 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD APR 1 PY 1999 VL 265 IS 3-4 BP 565 EP 583 DI 10.1016/S0378-4371(98)00475-0 PG 19 WC Physics, Multidisciplinary SC Physics GA 182FV UT WOS:000079489200022 ER PT J AU Machavariani, GY Rozenberg, GK Pasternak, MP Naaman, O Taylor, RD AF Machavariani, GY Rozenberg, GK Pasternak, MP Naaman, O Taylor, RD TI High-pressure metallization and amorphization of the molecular crystal Sn(IBr)(2) SO PHYSICA B LA English DT Article; Proceedings Paper CT 36th Meeting of the European High Pressure Research Group (EHPRG) CY SEP 07-11, 1998 CL ACIREALE, ITALY SP European Phys Soc, Ist Nazl Fisica Materia, Consiglio Nazl Ricerche - Gruppo Nazl Struttura Materia, Ist Nazl Fisica Nucleare - Sezione Catania, Presidenza Provincia Regionale Catania, Azienda Provinciale Turismo Catania, Ente Parco dell'Etna, Banca Roma DE insulator-metal transition; amorphization; molecular solids ID SNI4; GEI4 AB An insulator-to-metal transition concurring with amorphization is found in the cubic (Pa (3) over bar) molecular crystal Sn(IBr)(2) at P approximate to 20 GPa. Measurements were carried out with diamond-anvil cells at pressures up to similar to 30 GPa using resistance measurements, X-ray diffraction (XRD), and Sn-119 Mossbauer spectroscopy (MS). With increasing pressure a new crystalline phase is observed in the 10-23 GPa range; at P approximate to 16 GPa, a gradual onset of structural disorder is first observed, and full amorphization takes place at P greater than or equal to 23 GPa. Both electronic properties as measured by R(P,T) and MS data are consistent with a gradual growth of disordered (SnI2Br2)(n) polymeric chains, formed by intermolecular I-I bonding allowing for electronic delocalization to occur. Upon decompression both XRD and Sn-119 MS show a significant pressure hysteresis. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Machavariani, GY (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NR 8 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD APR PY 1999 VL 265 IS 1-4 BP 105 EP 108 DI 10.1016/S0921-4526(98)01336-2 PG 4 WC Physics, Condensed Matter SC Physics GA 182ZH UT WOS:000079527700020 ER PT J AU Ree, FH Winter, NW Glosli, JN Viecelli, JA AF Ree, FH Winter, NW Glosli, JN Viecelli, JA TI Kinetics and thermodynamic behavior of carbon clusters under high pressure and high temperature SO PHYSICA B LA English DT Article; Proceedings Paper CT 36th Meeting of the European High Pressure Research Group (EHPRG) CY SEP 07-11, 1998 CL ACIREALE, ITALY SP European Phys Soc, Ist Nazl Fisica Materia, Consiglio Nazl Ricerche - Gruppo Nazl Struttura Materia, Ist Nazl Fisica Nucleare - Sezione Catania, Presidenza Provincia Regionale Catania, Azienda Provinciale Turismo Catania, Ente Parco dell'Etna, Banca Roma DE carbon clusters; kinetics; graphite-diamond transition; diffusion ID LIQUID PHASE-CHANGE; GRAPHITE; DIAMOND AB Physical processes that govern the growth kinetics of carbon clusters at high pressure and high temperature are: (a) structural sp(3)-to-sp(2) and sp(2)-to-sp bonding changes and (b) cluster diffusion.. Our study on item (a) deals with ab initio and semi-empirical quantum mechanical calculations to examine effects of cluster size on the relative stability of graphite and diamond clusters and the energy barrier between the two. We have also made molecular dynamics simulations using the Brenner bond order potential to show that the melting line of diamond based on the Brenner potential is reasonable and that the liquid structure changes from mostly sp-bonded carbon chains to mostly sp(3)-bonding over a narrow pressure interval. We examined item (b) by using the time-dependent cluster size distribution function obtained from the relevant Smoluchowski equations. The resulting surface contribution to the Gibbs free energy of carbon clusters was implemented in a thermochemical equilibrium code and also to a new detonation model in a hydrodynamic code to examine the behavior of carbon-rich explosives. We find that carbon-rich explosives are sensitive to the metastability of graphitic carbon clusters and also to a delayed release of the surface energy of carbon clusters by the slow diffusive clustering processes. Published by Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Ree, FH (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. EM ree1@llnl.gov NR 20 TC 40 Z9 41 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD APR PY 1999 VL 265 IS 1-4 BP 223 EP 229 DI 10.1016/S0921-4526(98)01380-5 PG 7 WC Physics, Condensed Matter SC Physics GA 182ZH UT WOS:000079527700042 ER PT J AU Shaltiel, D Bezalel, M Golosovsky, M Kwok, WK Fendrich, JA AF Shaltiel, D Bezalel, M Golosovsky, M Kwok, WK Fendrich, JA TI Induced microwave absorption by magnetic modulation in untwinned and twinned YBaCuO crystals and its comparison with resistivity measurements SO PHYSICA C LA English DT Article DE induced microwave absorption; magnetic modulation; YBaCuO crystals; resistivity ID HIGH-TEMPERATURE SUPERCONDUCTORS; LOCK-IN TRANSITION; MELTING TRANSITION; SINGLE-CRYSTALS; YBA2CU3O7-DELTA; FIELD; DISSIPATION; DEPENDENCE; LATTICE; STATE AB We studied the magnetic field modulated microwave absorption across T-c for an untwinned and for a twinned YBa2Cu3O7-delta crystal(T-c congruent to 93 K) which were cleaved from the same high quality single crystal. The absorption signals were analyzed using the Tinkham model. A good fit to the model was obtained for the untwinned crystal for B parallel to c and for B > 0.2 T, while for the twinned crystal we observed pronounced deviations from the model which we attribute to the presence of twin boundary pinning. The angular dependence of the activation energy of vortex motion in the untwinned crystal shows a sharp increase when the direction of magnetic field is almost parallel to the a-b plane, which is suggestive of a lock-in transition. Although field-dependent resistivity measurements on untwinned crystals clearly demonstrate a vortex melting transition, microwave studies do not reveal any signature of it. This agrees with results of other groups showing that high frequency measurements in YbaCuO(7-delta) single crystals, unlike Bi2Sr2CaCu2Ox single crystals, are rather insensitive to the vortex melting transition. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Argonne Natl Lab, Mat Sci & Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. RP Shaltiel, D (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. RI Golosovsky, Michael/E-1401-2012; Golosovsky, Michael/L-8303-2013 OI Golosovsky, Michael/0000-0003-3814-4539 NR 26 TC 6 Z9 6 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 APR 1 PY 1999 VL 315 IS 1-2 BP 23 EP 35 DI 10.1016/S0921-4534(99)00190-2 PG 13 WC Physics, Applied SC Physics GA 191RH UT WOS:000080035000003 ER PT J AU Ashworth, SP Suenaga, M AF Ashworth, SP Suenaga, M TI The calorimetric measurement of losses in HTS tapes due to ac magnetic fields and transport currents SO PHYSICA C LA English DT Article DE calorimetric measurement; HTS tapes; magnetic fields; transport currents AB We report a simple technique for the measurement of energy losses in HTS tape carrying ac currents in ac magnetic fields at liquid nitrogen temperatures. This method is based on measuring the temperature rise of a thermally insulated tape and in the present form is able to measure losses down to 0.01 W m(-1). We present data obtained by this method confirming previously published results for the losses at 100 Hz due to in phase ac currents and magnetic fields as measured electrically. Using this calorimetric method we are able to measure the effect of phase differences between current and field. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. RP Ashworth, SP (reprint author), Brookhaven Natl Lab, Div Mat Sci, POB 5000, Upton, NY 11973 USA. NR 4 TC 48 Z9 48 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 1 PY 1999 VL 315 IS 1-2 BP 79 EP 84 DI 10.1016/S0921-4534(99)00216-6 PG 6 WC Physics, Applied SC Physics GA 191RH UT WOS:000080035000009 ER PT J AU Qiu, YH Burgdorfer, J AF Qiu, YH Burgdorfer, J TI Group-theoretical approach to final-state angular correlations in double photoionization of helium SO PHYSICAL REVIEW A LA English DT Article ID NEAR-THRESHOLD; CROSS-SECTIONS; EXCITED-STATES; IONIZATION; CLASSIFICATION; ENERGIES; HE AB We extend the well-known O(4) group-theoretical method for the classification of doubly excited states to the two-electron continuum. The analytical continuation of the approximate dynamic symmetry group across the double ionization threshold is isomorphic to the homogeneous Lorentz group O(3,1). The infinite-dimensional irreducible representations of O(3,1) provide approximate wave functions, which incorporate electron-electron angular correlations. Moreover, the labels of the representations can be interpreted as approximate quantum numbers, which allow the extension of well-known propensity rules from double excitation to double ionization. Employing the dynamic O(3,1) symmetry group and a new method to calculate complex Wigner (9-j) coefficients, we determine the angular distributions of the photoelectrons for double photoionization of helium near threshold. We find remarkable agreement with recent measurements. Similarities to and differences from other calculations arl discussed. [S1050-2947(99)00204-8]. C1 Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Qiu, YH (reprint author), Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. NR 36 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1999 VL 59 IS 4 BP 2738 EP 2743 DI 10.1103/PhysRevA.59.2738 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 184JT UT WOS:000079609100035 ER PT J AU Jones, MD Ortiz, G Ceperley, DM AF Jones, MD Ortiz, G Ceperley, DM TI Spectrum of neutral helium in strong magnetic fields SO PHYSICAL REVIEW A LA English DT Article ID HARTREE-FOCK; ENERGY-LEVELS; SYSTEMS; ATOMS; STATES AB We present extensive and accurate calculations for the excited-state spectrum of spin-polarized neutral helium in a range of magnetic field strengths up to 10(12) G. Of considerable interest to models of magnetic white dwarf stellar atmospheres, we also present results for the dipole strengths of the low-lying transitions among these states. Our methods rely on a systematically saturated basis set approach to solving the Hartree Fock self-consistent field equations, combined with an ''exact' stochastic method to estimate the residual basis set truncation error and electron correlation effects. We also discuss the applicability of the adiabatic approximation to strongly magnetized multielectron atoms. [S1050-2947(99)02504-4]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. RP Jones, MD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Ceperley, David/A-6858-2008 NR 20 TC 37 Z9 37 U1 0 U2 3 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 APR PY 1999 VL 59 IS 4 BP 2875 EP 2885 DI 10.1103/PhysRevA.59.2875 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 184JT UT WOS:000079609100051 ER PT J AU Shiell, RC Evans, M Stimson, S Hsu, CW Ng, CY Hepburn, JW AF Shiell, RC Evans, M Stimson, S Hsu, CW Ng, CY Hepburn, JW TI Characteristics of correlation satellites below 25 eV in xenon probed by pulsed-field-ionization-zero-kinetic-energy photoelectron spectroscopy SO PHYSICAL REVIEW A LA English DT Article ID HIGH-RESOLUTION; RARE-GASES; CROSS-SECTIONS; SYNCHROTRON-RADIATION; 5S PHOTOIONIZATION; RYDBERG STATES; THRESHOLD; SPECTRA; XE; DISTRIBUTIONS AB The technique of pulsed-field-ionization-zero-kinetic-energy photoelectron spectroscopy, typically applied to the investigation of ionic states of atoms and molecules resulting from single electron excitation, has been used to probe all known correlation ionic states of xenon up to 25 eV. The high-resolution (1 meV) spectra that result show the formation of satellite states clearly resolved from their neighbors. Their intensities are com parable to that of the 5s5p(6 2)S(1/2) main line ionic state and for a given multiplet are relatively independent of the total angular momentum of the ionic state formed. The Rydberg states converging onto different ionic limits demonstrate effective lifetimes that are related to the excitation of the associated ionic core. These spectra allow the determination of relative intensities, and from them, the partial cross sections for the formation of each state at threshold. This supplements the existing intensity studies from the near-threshold to the x-ray region and increases our understanding of the dominant correlation processes within this atom as a function of photon energy. [S1050-2947(99)04804-0]. C1 Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Shiell, RC (reprint author), Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. NR 31 TC 8 Z9 8 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1999 VL 59 IS 4 BP 2903 EP 2909 DI 10.1103/PhysRevA.59.2903 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 184JT UT WOS:000079609100054 ER PT J AU Unanyan, RG Shore, BW Bergmann, K AF Unanyan, RG Shore, BW Bergmann, K TI Laser-driven population transfer in four-level atoms: Consequences of non-Abelian geometrical adiabatic phase factors SO PHYSICAL REVIEW A LA English DT Article ID MULTILEVEL SYSTEMS; GAUGE STRUCTURE; PULSES; MOLECULES; INVERSION; PASSAGE; STATES; TIME AB We analyze the influence of three pulsed laser fields interacting with a four-state atomic system for which there occur two degenerate population-trapping dressed states. We present a simple expression for the geometrical phase acquired by such an atom during a stimulated Pal-nan adiabatic passage (STIRAP) process using a delay between Stokes and pump pulses, during which the two Rabi frequencies adiabatically traverse a closed path in the parameter space. We describe: techniques that can produce (geometrical) state-vector phases that are independent of the longitudial velocity with which atoms move across a laser beam, and that are insensitive to radiative decay from the intermediate excited state. The geometrical phase can be changed by changing the relative delay of the pulses. The geometrical phase can be measured by observing the population in atomic stares. We show that when the pump and Stokes pulses are properly timed, high population transfer from the initial state to the target state is achieved. In the adiabatic limit the robustness of the population transfer is equivalent to that of STIRAP. [S1050-2947(99)05104-5]. C1 Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. Armenian Natl Acad Sci, Phys Res Inst, Ashtarak 378410 2, Armenia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Unanyan, RG (reprint author), Univ Kaiserslautern, Fachbereich Phys, Postfach 3049, D-67653 Kaiserslautern, Germany. RI BERGMANN, KLAAS/D-5543-2011 NR 22 TC 156 Z9 158 U1 1 U2 13 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 APR PY 1999 VL 59 IS 4 BP 2910 EP 2919 DI 10.1103/PhysRevA.59.2910 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 184JT UT WOS:000079609100055 ER PT J AU Yatsenko, LP Halfmann, T Shore, BW Bergmann, K AF Yatsenko, LP Halfmann, T Shore, BW Bergmann, K TI Photoionization suppression by continuum coherence: Experiment and theory SO PHYSICAL REVIEW A LA English DT Article ID ACCURATE OSCILLATOR-STRENGTHS; LASER-INDUCED STRUCTURE; HYDROGEN-LIKE ATOMS; POPULATION TRANSFER; TRANSITION-PROBABILITIES; HARMONIC-GENERATION; AUTOIONIZING STATES; BRANCHING RATIOS; STARK SHIFTS; IONIZATION AB We present experimental and theoretical results of a detailed study of laser-induced continuum structures (LICS's) in the photoionization continuum of helium out of the metastable state 2s S-1(0). The continuum dressing, with a 1064-nm laser, couples the same region of the continuum to the 4s S-1(0) state. The experimental data, presented for a range of intensities, show pronounced ionization suppression (by as much as 70% with respect to the fat-from-resonance value) as well as enhancement, in a Beutler-Fano resonance profile. This ionization suppression is a clear indication of population trapping mediated by coupling to a continuum. We present experimental results demonstrating the effect of pulse delay upon the LICS's, and for the behavior of LICS's for both weak and strong probe pulses. Simulations based upon numerical solution of the Schrodinger equation model the experimental results. The atomic parameters (Rabi frequencies and Stark shifts) are calculated using a simple model-potential method for the computation of the needed wave functions. The simulations of the LICS profiles are in excellent agreement with experiment. We also present an analytic formulation of pulsed LICS's. We show that in the case of a probe pulse shorter than the dressing one, the LICS profile is the convolution of the power spectra of the probe pulse with the usual Fano profile of stationary LICS's. We discuss some consequences of deviation from steady-state theory. [S1050-2917(99)06604-4]. C1 Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. Ukrainian Acad Sci, Inst Phys, UA-252650 Kiev, Ukraine. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Yatsenko, LP (reprint author), Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. RI Halfmann, Thomas/O-4588-2014; BERGMANN, KLAAS/D-5543-2011 OI Halfmann, Thomas/0000-0002-1222-2669; NR 76 TC 43 Z9 44 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1999 VL 59 IS 4 BP 2926 EP 2947 DI 10.1103/PhysRevA.59.2926 PG 22 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 184JT UT WOS:000079609100057 ER PT J AU de Leon, JM de Coss, R Bishop, AR Trugman, SA AF de Leon, JM de Coss, R Bishop, AR Trugman, SA TI Isotopic substitution in a model polaronic system SO PHYSICAL REVIEW B LA English DT Article ID METAL-INSULATOR-TRANSITION; OXIDE SUPERCONDUCTORS; PHASE-SEPARATION; AXIAL OXYGEN; YBA2CU3O7; ANHARMONICITY; LA2-XSRXCUO4; SCATTERING; PHONONS; ORIGIN AB The effect of isotopic substitution in the excitation spectrum of a model polaronic system is presented. To study this effect we use a three-site many-body Hamiltonian, with two phonon modes, which includes electronic correlations and electron-phonon interactions. Under isotopic substitution, the shift of the lowest excitation energy changes sign for intermediate electron-phonon coupling, coinciding with the onset of polaronic behavior. This manifests as a strong change of the dynamics of polaron tunneling, a behavior opposite to that found in purely phonon excitations. Additionally, a small change in the static polaronic distortion appears under isotopic substitution. This change in the local structure has opposite signs for low and intermediate electron-phonon coupling compared to that found in the strong-coupling limit. [S0163-1829(99)08013-3]. C1 Inst Politecn Nacl, Ctr Invest & Estudios Avanzados, Merida 97310, Yucatan, Mexico. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP de Leon, JM (reprint author), Inst Politecn Nacl, Ctr Invest & Estudios Avanzados, Merida 97310, Yucatan, Mexico. RI Mustre de Leon, Jose/B-5630-2009 OI Mustre de Leon, Jose/0000-0002-0513-2323 NR 24 TC 9 Z9 9 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 1999 VL 59 IS 13 BP 8359 EP 8362 DI 10.1103/PhysRevB.59.8359 PG 4 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100005 ER PT J AU Cynn, H Yoo, CS AF Cynn, H Yoo, CS TI Equation of state of tantalum to 174 GPa SO PHYSICAL REVIEW B LA English DT Article ID GOLD; CALIBRATION; PRESSURE; MBAR AB The volume compression of tantalum was measured to 174 GPa in a diamond-anvil cell using angle-resolved synchrotron x-ray diffraction. A third-order Birch-Murnaghan equation-of-state constrains the compression data rather well with the zero-pressure isothermal bulk modulus B-OT 194.7(4.8) Cpa and the first pressure derivative B'=3.4(0.1). These values are consistent with the previous ultrasonic results, B-OS=196 GPa and B'=3.8, but are different from the previous x-ray compression results, B-OT=231GPa and B'=2.5. The current compression data also demonstrate that the bce phase of Ta continues to be stable to 174 GPa, which qualifies tantalum for a pressure standard in static high-pressure experiments. [S0163-1829(99)04713-X]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Cynn, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 28 TC 92 Z9 96 U1 1 U2 17 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 APR 1 PY 1999 VL 59 IS 13 BP 8526 EP 8529 DI 10.1103/PhysRevB.59.8526 PG 4 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100041 ER PT J AU Fishman, RS Liu, SH AF Fishman, RS Liu, SH TI Magnetic susceptibility of gamma-Mn alloys SO PHYSICAL REVIEW B LA English DT Article ID SPIN-DENSITY WAVE; LATTICE DISTORTION; ANTIFERROMAGNETISM; DYNAMICS AB This paper provides theoretical results for the magnetic susceptibility in the single (S), double (D), and triple (T) spin-density wave (SDW) states of gamma-Mn alloys. Whereas the S SDW state is collinear, the D and T SDW states are noncollinear phases which are stabilized at higher impurity concentrations. As expected, the susceptibility along any spin direction is suppressed below the Neel temperature. Averaged over all possible domains, the magnetic susceptibility of each SDW phase approaches the same limit near the Neel temperature. At low temperatures, however, the average susceptibility depends on the relative sizes of the electron and hole Fermi surfaces. For Fermi surfaces of approximately the same size, the average susceptibility is largest in the S SDW state and smallest in the T SDW state. But when one Fermi surface is sufficiently larger than the other, the relative magnitudes of the average susceptibilities are reversed. As a consequence, the transition between different SDW phases with temperature or doping concentration should be marked by a sudden change in the magnetic susceptibility. [S0163-1829(99)03213-0]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Fishman, RS (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Fishman, Randy/C-8639-2013 NR 19 TC 8 Z9 8 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 APR 1 PY 1999 VL 59 IS 13 BP 8672 EP 8680 DI 10.1103/PhysRevB.59.8672 PG 9 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100058 ER PT J AU Fishman, RS Liu, SH AF Fishman, RS Liu, SH TI Magnetoelastic effects and spin excitations in gamma-Mn alloys SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC EXCITATIONS; DENSITY-WAVE; MARTENSITIC-TRANSFORMATION; ITINERANT ANTIFERROMAGNET; TEMPERATURE-DEPENDENCE; LATTICE DISTORTION; CHROMIUM; MANGANESE; TRANSITION; MN90CU10 AB A two-band model which includes the magnetoelastic interaction is used to study the magnetization and spin dynamics of gamma-Mn alloys. As previously believed, single (S), double (D), and triple (T) spin-density wave (SDW) states are found in fct (c < a and c > a) and fee (c = a) lattices, respectively. When the magnetoelastic coupling constant kappa exceeds the critical value kappa(c), both the structural and magnetic phase transitions become first order. This critical value drops to zero at the triple point, where the commensurate and incommensurate SDW phase boundaries meet. In agreement with experiments on fct MnNi and fee FeMn alloys, we find that the gap Delta(sw)(T) in the spin-wave dispersion is proportional to the 3/2 power of the sublattice magnetization M(T). For the noncollinear D and T SDW magnetic phases observed in MnNi and FeMn alloys, we find an additional class of collective modes. This class includes a Goldstone mode which is produced by the modified dispersion of holes not directly involved in the SDW. We also find high-frequency excitations with energies of order Delta, where 2 Delta approximate to 2 eV is the energy gap in the quasiparticle spectrum. Although these incoherent excitations have the same frequencies in the D and T SDW phases, their neutron-scattering cross sections should be 33% larger in the TSDW phase. [S0163-1829(99)05413-2]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Fishman, RS (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Fishman, Randy/C-8639-2013 NR 46 TC 8 Z9 8 U1 1 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 1999 VL 59 IS 13 BP 8681 EP 8694 DI 10.1103/PhysRevB.59.8681 PG 14 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100059 ER PT J AU Argyriou, DN Mitchell, JF Radaelli, PG Bordallo, HN Cox, DE Medarde, M Jorgensen, JD AF Argyriou, DN Mitchell, JF Radaelli, PG Bordallo, HN Cox, DE Medarde, M Jorgensen, JD TI Lattice effects and magnetic structure in the layered colossal magnetoresistance manganite La2-2xSr1+2xMn2O7, x = 0.3 SO PHYSICAL REVIEW B LA English DT Article ID INTERPLANE TUNNELING MAGNETORESISTANCE; LA1.2SR1.8MN2O7; CRYSTAL; LA1.4SR1.6MN2O7 AB We report on the temperature dependence of the crystal and magnetic structure of the layered colossal magnetoresistive manganite, La2-2xSr1+2xMn2O7, x = 0.3. Neutron-diffraction measurements show that the insulator-metal (IM) transition (T-IM) at similar to 100 K is accompanied by a ferromagnetic (FM) ordering of spins within MnO6 bilayers (intrabilayer coupling), but with an antiferromagnetic coupling between neighboring bilayers (interbilayer coupling). Below T-IM, the Mn spins rotate from similar to 45 degrees inclination to the c axis until they are almost parallel to the c axis at 5 K. Coincident with this spin reorientation, a FM c axis component develops below 75 K. Evidence from both neutron and synchrotron x-rap-diffraction experiments suggest that the FM c-axis magnetic moment results from a second layered manganite phase with composition 0.3 less than or equal to x less than or equal to 0.32. This observation emphasizes the need for thorough examination of the homogeneity when measuring bulk properties (e.g., magnetization, transport) of nominally x=0.3 samples. Associated with the electronic and magnetic transitions, a pronounced lattice response along the c axis (observed in both phases) signals a transfer of charge into d(x2)-(y2) orbitals in the low-temperature phase. That the lattice effects here are opposite in sign to those observed in the x=0.4 layered manganite points to the sensitivity of the spin-lattice-charge coupling to dopant concentration in these reduced-dimensionality manganites. [S0163-1829(99)00513-5]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. Brookhaven Natl Lab, Upton, NY 11973 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Argyriou, DN (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, POB 1663, Los Alamos, NM 87545 USA. RI Radaelli, Paolo/C-2952-2011; D20, Diffractometer/O-3123-2013; Bordallo, Heloisa/I-6836-2012 OI Radaelli, Paolo/0000-0002-6717-035X; D20, Diffractometer/0000-0002-1572-1367; Bordallo, Heloisa/0000-0003-0750-0553 NR 15 TC 106 Z9 113 U1 1 U2 13 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 APR 1 PY 1999 VL 59 IS 13 BP 8695 EP 8702 DI 10.1103/PhysRevB.59.8695 PG 8 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100060 ER PT J AU Kosugi, M Matsuda, Y Gaifullin, MB Bulaevskii, LN Chikumoto, N Konczykowski, M Shimoyama, J Kishio, K Hirata, K AF Kosugi, M Matsuda, Y Gaifullin, MB Bulaevskii, LN Chikumoto, N Konczykowski, M Shimoyama, J Kishio, K Hirata, K TI Josephson coupling in the vortex-liquid state of Bi2Sr2CaCu2O8+delta with columnar defects SO PHYSICAL REVIEW B LA English DT Article ID ION IRRADIATED BI2SR2CACU2O8+DELTA; PARALLEL MAGNETIC-FIELDS; T-C SUPERCONDUCTORS; PLASMA RESONANCE; LAYERED SUPERCONDUCTORS; REVERSIBLE MAGNETIZATION; SINGLE-CRYSTALS; MIXED-STATE; TRANSITION; VORTICES AB The interlayer Josephson coupling in the vortex-liquid phase of Bi2Sr2CaCu2O8+delta with columnar defects is studied by means of the Josephson plasma resonance. At high temperatures well above the Bose-glass melting line, double resonance peaks appear as a function of the magnetic field in a narrow temperature range deep within the vortex-liquid state. This indicates that two types of vortex liquid, the well-coupled and the decoupled pancake vortex liquids, appear in the irradiated crystals. The pancake vortices tend to align and couple with increasing magnetic field when it approaches approximately one-third of the matching field. From the angular and frequency dependences of the resonance, we estimate the c-axis correlation length of the pancake vortices quantitatively. [S0163-1829(99)06613-8]. C1 Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 106, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Int Superconduct Technol Ctr, Superconducting Res Lab, Minato Ku, Tokyo 105, Japan. Ecole Polytech, Solides Irradies Lab, F-91128 Palaiseau, France. Univ Tokyo, Dept Superconduct, Bunkyo Ku, Tokyo 113, Japan. Natl Res Inst Metals, Tsukuba, Ibaraki 305, Japan. RP Kosugi, M (reprint author), Oki Elect Ind Co Ltd, Hachioji, Tokyo 193, Japan. RI Gaifullin, Marat/G-4803-2015 NR 47 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 APR 1 PY 1999 VL 59 IS 13 BP 8970 EP 8977 DI 10.1103/PhysRevB.59.8970 PG 8 WC Physics, Condensed Matter SC Physics GA 186WQ UT WOS:000079754100093 ER PT J AU Manosa, L Zarestky, J Bullock, M Stassis, C AF Manosa, L Zarestky, J Bullock, M Stassis, C TI Low-lying phonon dispersion curves of D0(3) Cu3Al(+Be) SO PHYSICAL REVIEW B LA English DT Article ID SHAPE-MEMORY ALLOYS; PREMARTENSITIC STATE; ENTROPY CHANGE; MARTENSITE; PHASE AB The low-lying phonon dispersion curves of a DO3 ordered Cu3Al(+Be) shape-memory alloy were measured, at room temperature, along the [xi 00], [xi xi 0], [xi xi xi], [xi xi 1], and [1/2, 1/2, xi] symmetry directions. As in other bcc metals and alloys, we find that the frequencies of the TA(2)[xi xi 0] modes are relatively low and that the L[xi xi xi] branch exhibits a pronounced dip at xi=2/3. The measured low-lying phonon dispersion curves are quite similar to those of a bcc structure. Actually, a fifth-nearest-neighbor force constant bcc model provides a satisfactory fit to the low-lying phonon dispersion curves of this alloy. This model was used to evaluate the elastic constants, the phonon density of states, and the lattice specific heat. The results of these calculations are in good agreement with macroscopic measurements of the elastic constants and specific heat of this alloy. [S0163-1829(99)02114-1]. C1 Univ Barcelona, Fac Fis, Dept Estructura & Constituents Mat, E-08028 Barcelona, Spain. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Manosa, L (reprint author), Univ Barcelona, Fac Fis, Dept Estructura & Constituents Mat, Diagonal 647, E-08028 Barcelona, Spain. RI Manosa, Lluis/D-8579-2014 OI Manosa, Lluis/0000-0002-1182-2670 NR 14 TC 6 Z9 6 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 APR 1 PY 1999 VL 59 IS 14 BP 9239 EP 9242 DI 10.1103/PhysRevB.59.9239 PG 4 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300028 ER PT J AU Li, QA Gray, KE Mitchell, JF AF Li, QA Gray, KE Mitchell, JF TI Spin-independent and spin-dependent conductance anisotropy in layered colossal-magnetoresistive manganite single crystals SO PHYSICAL REVIEW B LA English DT Article ID RESISTIVITY; LA1.2SR1.8MN2O7 AB Results are reported for the conductance anisotropies in single crystals of the layered colossal magnetoresistive manganites. Well below the magnetic ordering temperatures, the zero-field anisotropy increases from similar to 230 for La1.24Sr1.76Mn2O7 to >10000 for La1.4Sr1.6Mn2O7, consistent with a c-axis antiferromagnetic ground state in the latter, while the spin-independent conductivity anisotropy only increases from similar to 230 to similar to 300. Significant c-axis ferromagnetic fluctuations are seen in La1.4Sr1.6Mn2O7, but no evidence is found for the recently reported two-dimensional magnetic ordering transition at higher temperatures. Direct evidence suggests that spin-orbit coupling is weaker than any other possible sources of orbital ordering. [S0163-1829(99)11613-8]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Li, QA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Li, Qingan/L-3778-2013 NR 17 TC 27 Z9 27 U1 1 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 APR 1 PY 1999 VL 59 IS 14 BP 9357 EP 9361 DI 10.1103/PhysRevB.59.9357 PG 5 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300040 ER PT J AU Moshopoulou, EG Bordet, P Capponi, JJ AF Moshopoulou, EG Bordet, P Capponi, JJ TI Superstructure and superconductivity in Li1-xNbO2 (x approximate to 0.7) single crystals SO PHYSICAL REVIEW B LA English DT Article ID BOND-VALENCE PARAMETERS; ELECTRONIC-STRUCTURE; LIXNBO2; SPECTRA; NAXNBO2 AB Single-crystal x-ray and electron diffraction studies established a direct relationship between lithium content, crystal structure, niobium valence, and the appearance of superconductivity in the system Li1-xNbO2. The induction of superconductivity by removal of x approximate to 0.3 lithium is accompanied by the appearance of a superstructure with unit cell axbx2c, where axbxc is the unit cell of the nonsuperconductor LiNbO2. Detailed structural analysis, based on both the main and superlattice reflections, demonstrated that the superconductor Li1-xNbO2 [x approximate to 0.79(9), T(c)approximate to 5.5 K] has P (3) over bar m1 symmetry,with interlayer ordering of lithium vacancies and weakly distorted [NbO2] network. As a result of this distortion, Nb rations of the different layers have different valences (3.7(+) and 2.6(+)). [S0163-1829(99)10713-6]. C1 Univ Grenoble 1, CNRS, Lab Cristallog, F-38042 Grenoble 09, France. RP Moshopoulou, EG (reprint author), Brookhaven Natl Lab, Dept Phys, Solid State Phys Grp, Bldg 510B, Upton, NY 11973 USA. EM evagelia@bnl.gov NR 24 TC 14 Z9 14 U1 1 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 1999 VL 59 IS 14 BP 9590 EP 9599 DI 10.1103/PhysRevB.59.9590 PG 10 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300068 ER PT J AU Hettler, MH Hirschfeld, PJ AF Hettler, MH Hirschfeld, PJ TI Scattering by impurity-induced order-parameter "holes" in d-wave superconductors SO PHYSICAL REVIEW B LA English DT Article ID HEAVY-FERMION SUPERCONDUCTORS; TEMPERATURE PENETRATION DEPTH; UNCONVENTIONAL SUPERCONDUCTORS; BOUND-STATES; YBA2CU3O6.95; SUPPRESSION AB Nonmagnetic impurities in d-wave superconductors cause strong local suppressions of the order parameter. We investigate the observable effects of the scattering of such suppressions in bulk samples by treating the order parameter "hole" as a pointlike off-diagonal scatterer heated within a self-consistent t-matrix approximation. Strong scattering potentials lead to a finite-energy spectral feature in the d-wave "impurity band," the observable effects of which include enhanced low-temperature microwave power absorption and a stronger sensitivity of the London penetration depth to disorder than found previously in simpler "dirty" d-wave models. [S0163-1829(99)03413-X]. C1 Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. RP Hettler, MH (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Hirschfeld, Peter /A-6402-2010 NR 25 TC 30 Z9 30 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 APR 1 PY 1999 VL 59 IS 14 BP 9606 EP 9610 DI 10.1103/PhysRevB.59.9606 PG 5 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300070 ER PT J AU Jiang, XY Li, QM Soukoulis, CM AF Jiang, XY Li, QM Soukoulis, CM TI Symmetry between absorption and amplification in disordered media SO PHYSICAL REVIEW B LA English DT Article ID SPONTANEOUS EMISSION; AMPLIFYING MEDIUM; LOCALIZATION; LIGHT; REFLECTION; LASER; BACKSCATTERING; TRANSMISSION; AMPLIFIERS AB We address the issue of whether amplification, like absorption, suppresses wave transmission at large gain, as has been claimed in previous studies of wave propagation in active random media. A closer examination reveals that the paradoxical symmetry between absorption and amplification is an artifact of unphysical solutions from the time-independent wave equation. Solutions from the time-dependent equation demonstrate clearly that when gain is above the threshold, the amplitude of both the transmitted and the reflected wave actually increases with time, apparently without bound. The implications of the current finding is discussed. [S0163-1829(99)50314-7]. C1 Iowa State Univ, Ames Lab, US Dept Energy, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Jiang, XY (reprint author), Iowa State Univ, Ames Lab, US Dept Energy, Ames, IA 50011 USA. RI Soukoulis, Costas/A-5295-2008 NR 27 TC 42 Z9 42 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 APR 1 PY 1999 VL 59 IS 14 BP R9007 EP R9010 DI 10.1103/PhysRevB.59.R9007 PG 4 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300001 ER PT J AU Kang, WN Kang, BW Chen, QY Wu, JZ Yun, SH Gapud, A Qu, JZ Chu, WK Christen, DK Kerchner, R Chu, CW AF Kang, WN Kang, BW Chen, QY Wu, JZ Yun, SH Gapud, A Qu, JZ Chu, WK Christen, DK Kerchner, R Chu, CW TI Scaling of the Hall resistivity in epitaxial HgBa2CaCu2O6+delta thin films with columnar defects SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; FLUX-FLOW; C-AXIS; STATE; BEHAVIOR; YBA2CU3O7; CONDUCTIVITY; DEPENDENCE; FIELD AB We have studied the Hall scaling relation rho(xy)=A rho(xx)(beta) for the mixed-state Hall effects of HgBa2CaCu2O6+delta thin films before and after irradiation by high-energy Xe ions. beta increases from 1.0+/-0.1 to 2.0+/-0.1 as a perpendicular magnetic field increases from 0 to 8 T, and increases from 1.0+/-0.1 to 1.5+/-0.05 as the angle between the columnar tracks and a 4 T field decreases from 75 degrees to 0 degrees. The observation of beta=1 is consistent with a recent theory based on d-wave superconductivity, in which the Hall angle was predicted to show a universal behavior that was independent of the mean free path of charge carriers in the low-field region. [S0163-1829(99)50114-8]. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Kang, WN (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. EM qchen@uh.edu NR 25 TC 18 Z9 20 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 APR 1 PY 1999 VL 59 IS 14 BP R9031 EP R9034 DI 10.1103/PhysRevB.59.R9031 PG 4 WC Physics, Condensed Matter SC Physics GA 186WT UT WOS:000079754300007 ER PT J AU Mueller, WF Jin, HQ Lewis, JM Reviol, W Riedinger, LL Carpenter, MP Baktash, C Garrett, JD Johnson, NR Lee, IY McGowan, FK Yu, CH Cwiok, S AF Mueller, WF Jin, HQ Lewis, JM Reviol, W Riedinger, LL Carpenter, MP Baktash, C Garrett, JD Johnson, NR Lee, IY McGowan, FK Yu, CH Cwiok, S TI High-spin structure in Au-181,Au-183 SO PHYSICAL REVIEW C LA English DT Article ID RARE-EARTH NUCLEI; SHAPE COEXISTENCE; ALIGNMENT PROCESSES; BAND STRUCTURES; INTRUDER BANDS; MASS NUCLEI; STATES; IR-177; DECAYS; REGION AB High-spin states were studied in Au-181,Au-183 and resulted in the identification of several new prolate rotational bands based on pi i (13/2), pi h(9/2), pi f (7/2), pi h(11/2), and within configurations. The alignment and moment of inertia features of the intruder bands are compared with ground-state bands in Pt nuclei. From these features, it can be concluded that a strongly interacting (pi h(9/2))(2) alignment is occurring in the pi i (13/2) bands in Au and the ground-state bands in Pt. In addition, bandhead energies and deformation parameters are calculated for deformed configurations in the framework of a microscopic-macroscopic shell-correction model. These calculations are compared with experimental values in Re and Ir, as well as, Au isotopes. Interaction properties between known pi h(9/2) and pi f (7/2) rotational bands are also discussed and compared with results from a cranked-shell model. Experimental B(M1)/B(E2) ratios between these bands are compared with results from a particle-rotor calculation. [S0556-2813(99)05304-2]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Warsaw Univ Technol, Inst Phys, PL-00662 Warsaw, Poland. RP Katholieke Univ Leuven, Inst Kern & Stralingsfys, B-3001 Louvain, Belgium. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 46 TC 42 Z9 44 U1 2 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1999 VL 59 IS 4 BP 2009 EP 2032 DI 10.1103/PhysRevC.59.2009 PG 24 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500023 ER PT J AU Aalseth, CE Avignone, FT Brodzinski, RL Collar, JI Garcia, E Gonzalez, D Hasenbalg, F Hensley, WK Kirpichnikov, IV Klimenko, AA Miley, HS Morales, A Morales, J de Solorzano, AO Osetrov, SB Pogosov, VS Puimedon, J Reeves, JH Salinas, A Sarsa, ML Smolnikov, AA Starostin, AS Tamanyan, AG Vasenko, AA Vasiliev, SI Villar, JA AF Aalseth, CE Avignone, FT Brodzinski, RL Collar, JI Garcia, E Gonzalez, D Hasenbalg, F Hensley, WK Kirpichnikov, IV Klimenko, AA Miley, HS Morales, A Morales, J de Solorzano, AO Osetrov, SB Pogosov, VS Puimedon, J Reeves, JH Salinas, A Sarsa, ML Smolnikov, AA Starostin, AS Tamanyan, AG Vasenko, AA Vasiliev, SI Villar, JA TI Neutrinoless double-beta decay of Ge-76: First results from the International Germanium Experiment (IGEX) with six isotopically enriched detectors SO PHYSICAL REVIEW C LA English DT Article ID SUPPRESSION; SE-82 AB The International Germanium Experiment (IGEX) has six HPGe detectors, isotopically enriched to 86% in Ge-76, containing approximately 90 active moles of Ge-76, These detectors of 2 kg each operate in the Canfranc Underground Laboratory (Spain) with pulse-shape analysis electronics, One detector (similar to 0.7 kg active volume) has been operating in the Baksan Low-Background Laboratory for several years. and two additional similar detectors will operate in Baksan. A maximum likelihood analysis of 74.84 active mole years of data yields a lower bound T(1/2)(0v)greater than or equal to 0.8 x 10(25) yr (90% C.L.), corresponding to [M-v] <(0.5-1.5) eV, depending on the theoretical nuclear matrix elements used to extract the neutrino mass parameter. [S0556-2813(99)01604-0]. C1 Univ S Carolina, Columbia, SC 29208 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Zaragoza, E-50009 Zaragoza, Spain. Inst Theoret & Expt Phys, Moscow 117259, Russia. Baksan Neutrino Observ, Inst Nucl Res, Neutrino 361609, Russia. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Univ S Carolina, Columbia, SC 29208 USA. RI Sarsa Sarsa, Maria Luisa/K-6108-2014; Villar, Jose Angel/K-6630-2014; OI Sarsa Sarsa, Maria Luisa/0000-0002-7552-1228; Villar, Jose Angel/0000-0003-0228-7589; Garcia Abancens, Eduardo/0000-0002-9827-2332 NR 22 TC 133 Z9 133 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1999 VL 59 IS 4 BP 2108 EP 2113 DI 10.1103/PhysRevC.59.2108 PG 6 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500033 ER PT J AU Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Britt, HC Chang, J Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Crawford, HJ Cumming, JB Debbe, R Dunlop, JC Eldredge, W Engelage, J Fung, SY Garcia, E Gushue, S Hamagaki, H Hansen, LF Hayano, RS Heintzelman, G Judd, E Kang, J Kim, EJ Kumagai, A Kurita, K Lee, JH Luke, J Miake, Y Mignerey, A Moskowitz, B Moulson, M Muentz, C Nagamiya, S Namboordiri, MN Ogilvie, CA Olness, J Remsberg, LP Sako, H Sangster, TC Seto, R Shea, J Shigaki, K Soltz, R Steadman, SG Stephans, GSF Tannenbaum, MJ Thomas, JH Ueno-Hayashi, S Videbaek, F Wang, F Wu, Y Xiang, H Xu, GH Yagi, K Yao, H Zajc, WA Zhu, F AF Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Britt, HC Chang, J Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Crawford, HJ Cumming, JB Debbe, R Dunlop, JC Eldredge, W Engelage, J Fung, SY Garcia, E Gushue, S Hamagaki, H Hansen, LF Hayano, RS Heintzelman, G Judd, E Kang, J Kim, EJ Kumagai, A Kurita, K Lee, JH Luke, J Miake, Y Mignerey, A Moskowitz, B Moulson, M Muentz, C Nagamiya, S Namboordiri, MN Ogilvie, CA Olness, J Remsberg, LP Sako, H Sangster, TC Seto, R Shea, J Shigaki, K Soltz, R Steadman, SG Stephans, GSF Tannenbaum, MJ Thomas, JH Ueno-Hayashi, S Videbaek, F Wang, F Wu, Y Xiang, H Xu, GH Yagi, K Yao, H Zajc, WA Zhu, F TI Simultaneous multiplicity and forward energy characterization of particle spectra in Au+Au collisions at 11.6A GeV/c SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION EXPERIMENTS AB In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (E-ZCAL) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events (sigma/sigma(int) < 12%) the proton dN/dy distributions do not depend on E-ZCAL but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on E-ZCAL and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/pi ratio even in the events with extreme multiplicity. [S0556-2813(99)03704-8]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Riverside, Riverside, CA 92507 USA. Columbia Univ, New York, NY 10027 USA. Nevis Labs, Irvington, NY 10533 USA. High Energy Accelerator Res Org, KEK, Ibaraki, Osaka 305, Japan. High Energy Accelerator Res Org, KEK, Tokyo 188, Japan. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Maryland, College Pk, MD 20742 USA. MIT, Cambridge, MA 02139 USA. Univ Tokyo, Sch Sci, Ctr Nucl Study, Tokyo 188, Japan. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Univ Tsukuba, Ibaraki, Osaka 305, Japan. Yonsei Univ, Seoul 120749, South Korea. RP Ahle, L (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Mignerey, Alice/D-6623-2011; seto, richard/G-8467-2011; Cumming, James/I-3358-2013; Hayano, Ryugo/F-7889-2012; HAMAGAKI, HIDEKI/G-4899-2014; OI Cumming, James/0000-0001-6930-0958; Hayano, Ryugo/0000-0002-1214-7806; Tannenbaum, Michael/0000-0002-8840-5314; Thomas, James/0000-0002-6256-4536; Ogilvie, Craig/0000-0002-5188-5123 NR 15 TC 62 Z9 64 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 APR PY 1999 VL 59 IS 4 BP 2173 EP 2188 DI 10.1103/PhysRevC.59.2173 PG 16 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500041 ER PT J AU Abdurashitov, JN Gavrin, VN Girin, SV Gorbachev, VV Ibragimova, TV Kalikhov, AV Khairnasov, NG Knodel, TV Kornoukhov, VN Mirmov, IN Shikhin, AA Veretenkin, EP Vermul, VM Yants, VE Zatsepin, GT Khomyakov, YS Zvonarev, AV Bowles, TJ Nico, JS Teasdale, WA Wark, DL Cherry, ML Karaulov, VN Levitin, VL Maev, VI Nazarenko, PI Shkol'nik, VS Skorikov, NV Cleveland, BT Daily, T Davis, R Lande, K Lee, CK Wildenhain, PS Elliott, SR Wilkerson, JF AF Abdurashitov, JN Gavrin, VN Girin, SV Gorbachev, VV Ibragimova, TV Kalikhov, AV Khairnasov, NG Knodel, TV Kornoukhov, VN Mirmov, IN Shikhin, AA Veretenkin, EP Vermul, VM Yants, VE Zatsepin, GT Khomyakov, YS Zvonarev, AV Bowles, TJ Nico, JS Teasdale, WA Wark, DL Cherry, ML Karaulov, VN Levitin, VL Maev, VI Nazarenko, PI Shkol'nik, VS Skorikov, NV Cleveland, BT Daily, T Davis, R Lande, K Lee, CK Wildenhain, PS Elliott, SR Wilkerson, JF CA SAGE Collaboration TI Measurement of the response of a gallium metal solar neutrino experiment to neutrinos from a Cr-51 source SO PHYSICAL REVIEW C LA English DT Article ID GALLEX; UNCERTAINTIES; CALIBRATION; ENRICHMENT; DETECTORS; MODELS; SAGE; SUN AB The neutrino capture rate measured by the Russian-American Gallium Experiment is well below that predicted by solar models. To check the response of this experiment to low-energy neutrinos, a 517 kCi source of Cr-51 was produced by irradiating 512.7 g of 92.4%-enriched Cr-50 in a high-flux fast neutron reactor. This source, which mainly emits monoenergetic 747-keV neutrinos, was placed at the center of a 13.1 ton target of liquid gallium and the cross section for the production of Ge-71 by the inverse beta decay reaction Ga-71(nu(e),e(-))Ge-71 was measured to be [5.55+/-0.60 (stat)+/-0.32 (syst)] X 10(-45) cm(2) The ratio of this cross section to the theoretical cross section of Bahcall for this reaction is 0.95 +/- 0.12 (expt)(-0.027)(+0.035) (theor) and to the cross section of Haxton is 0.87 +/- 0.11 (expt)+/- 0.09 (theor). This good agreement between prediction and observation implies that the overall experimental efficiency is correctly determined and provides considerable evidence for the reliability of the solar neutrino measurement. [S0556-2813(99)03803-0]. C1 Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Inst Phys & Power Engn, Obninsk, Russia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Mangyshlak Atom Energy Complex, Aktau, Kazakhstan. Univ Penn, Philadelphia, PA 19104 USA. Univ Washington, Seattle, WA 98195 USA. RP Russian Acad Sci, Inst Nucl Res, 60Th October Anniversary Prospect 7, Moscow 117312, Russia. RI Abdurashitov, Dzhonrid/B-2206-2014; Yants, Viktor/C-1038-2014; OI Abdurashitov, Dzhonrid/0000-0002-1577-1364; Wilkerson, John/0000-0002-0342-0217 NR 45 TC 134 Z9 134 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1999 VL 59 IS 4 BP 2246 EP 2263 DI 10.1103/PhysRevC.59.2246 PG 18 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500048 ER PT J AU Malov, DE Umar, AS Ernst, DJ Dean, DJ AF Malov, DE Umar, AS Ernst, DJ Dean, DJ TI Hadronic structure functions as distributions of classical strings SO PHYSICAL REVIEW C LA English DT Article ID COLLISIONS; MODEL AB Hadronic structure functions are modeled as a distribution of solutions to the classical string model of Nambu and Goto. In the model, the endpoints of the strings, identified as quarks, carry a finite amount of energy and momentum. The endpoint trajectories are assumed to be polygons and it is shown that the structure function in the scaling limit is directly related to the distribution of lengths of the straight line segments making up the polygons. The relationship is inverted to give an analytic expression for the distribution of straight line segments in terms of the structure function. The results are applied to the measured proton and pion structure functions. [S0556-2813(99)01504-6]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP Malov, DE (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Umar, Ahmet/J-4125-2013; OI Umar, Ahmet/0000-0002-9267-5253; Dean, David/0000-0002-5688-703X NR 22 TC 3 Z9 3 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 APR PY 1999 VL 59 IS 4 BP 2289 EP 2292 DI 10.1103/PhysRevC.59.2289 PG 4 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500056 ER PT J AU Savage, MJ AF Savage, MJ TI Pionic matrix elements in neutrinoless double-beta decay SO PHYSICAL REVIEW C LA English DT Article ID OPERATOR EXPANSION METHOD; GAUGE-THEORIES; CA-48; STATES; TE-128 AB Physics beyond the standard model of electroweak interactions that violates lepton number will, in general, induce operators involving the quark and lepton fields that violate lepton number. I point out that some matrix elements of particular operators are known. In the limit of exact SU(3) flavor symmetry the operator (u) over bar gamma(mu)(1 - gamma(5))d (u) over bar gamma(mu)(1 - gamma(5))d is part of the 27 representation responsible for Delta I = 3/2 strangeness changing decays in the standard model. At leading order in the chiral expansion there is only one coupling constant that describes the weak interactions of the pseudo-Goldstone bosons induced by the 27 representation. The observed branching fraction for K+ --> pi(+)pi(0) determines this coupling constant. Contributions of the form m(s) ln m(s) are used to estimate SU(3) breaking corrections to the relation between K+ --> pi(+) pi(0) and the pi(-)-->pi(+)e(-)e(-) interaction. [S0556-2813(99)03304-X]. C1 Univ Washington, Dept Phys, Seattle, WA 98915 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Univ Washington, Dept Phys, Seattle, WA 98915 USA. EM savage@phys.washington.edu NR 32 TC 1 Z9 1 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1999 VL 59 IS 4 BP 2293 EP 2296 DI 10.1103/PhysRevC.59.2293 PG 4 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500057 ER PT J AU Bleicher, M Reiter, M Dumitru, A Brachmann, J Spieles, C Bass, SA Stocker, H Greiner, W AF Bleicher, M Reiter, M Dumitru, A Brachmann, J Spieles, C Bass, SA Stocker, H Greiner, W TI Distinguishing hadronic cascades from hydrodynamic models in Pb(160A GeV)+Pb reactions by impact parameter variation SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; PHASE-TRANSITION AB We propose to study the impact parameter dependence of the (A) over bar/(p) over bar ratio in Pb(160A GeV) + Pb reactions. The (A) over bar/(p) over bar ratio is a sensible tool to distinguish between hadronic cascade models and hydrodynamical models, which assume chemical equilibrium and incorporate a possible phase transition to a quark-gluon plasma. [S0556-2813(99)50204-5]. C1 Univ Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, Germany. Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Duke Univ, Dept Phys, Durham, NC 27708 USA. RP Bleicher, M (reprint author), Univ Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, Germany. RI Bleicher, Marcus/A-2758-2010; Stoecker, Horst/D-6173-2013 OI Stoecker, Horst/0000-0002-3282-3664 NR 9 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1999 VL 59 IS 4 BP R1844 EP R1845 DI 10.1103/PhysRevC.59.R1844 PG 2 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500004 ER PT J AU Emel'yanov, V Khodinov, A Klein, SR Vogt, R AF Emel'yanov, V Khodinov, A Klein, SR Vogt, R TI Impact parameter dependence of J/psi and Drell-Yan production in heavy ion collisions at root S-NN = 17.3 GeV SO PHYSICAL REVIEW C LA English DT Article ID NUCLEAR-STRUCTURE; QUARK; QCD; PP AB In heavy inn collisions, J/psi and Drell-Yan production are expected to be affected by nuclear modifications to the free nucleon structure Functions. If these modifications, referred to here as shadowing, are proportional to the local nuclear density, the per nucleon cross sections will depend on centrality. Differences in quark and gluon shadowing will lead to a new source of impact parameter dependence of the J/psi to Drell-Yan production ratio. We calculate this ratio in the CERN NA50 acceptance with several shadowing parametrizations to explore its centrality dependence. [S0556-2813(99)50704-8]. C1 Moscow State Tech Univ, Moscow State Engn Phys Inst, Moscow 115409, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Emel'yanov, V (reprint author), Moscow State Tech Univ, Moscow State Engn Phys Inst, Kashirskoe Av 31, Moscow 115409, Russia. RI KHODINOV, ALEKSANDR/D-6269-2015 OI KHODINOV, ALEKSANDR/0000-0003-3551-5808 NR 24 TC 12 Z9 12 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 APR PY 1999 VL 59 IS 4 BP R1860 EP R1863 DI 10.1103/PhysRevC.59.R1860 PG 4 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500008 ER PT J AU Yu, CH Galindo-Uribarri, A Paul, SD Carpenter, MP Davids, CN Janssens, RVF Lister, CJ Seweryniak, D Uusitalo, J MacDonald, BD AF Yu, CH Galindo-Uribarri, A Paul, SD Carpenter, MP Davids, CN Janssens, RVF Lister, CJ Seweryniak, D Uusitalo, J MacDonald, BD TI Spectroscopy of the proton emitter I-109 SO PHYSICAL REVIEW C LA English DT Article ID GAMMA-RAY SPECTROSCOPY; HIGH-SPIN STATES; DRIP-LINE; EXCITED-STATES; NONCOLLECTIVE OBLATE; NUCLEI; DECAY; RADIOACTIVITY; FEATURES; BANDS AB Excited states in the proton-unbound nucleus I-109 were populated using the Fe-54(Ni-58.p2n) reaction at a beam energy of 220 MeV. Gamma rays in I-109 were identified using the rceoil-decay tagging technique. The analysis of proton-correlated gamma gamma coincidence data produced the yrast decay sequence in I-109, which can be tentatively assigned as built on the h(11/2) proton state based on systematic trends in the neighboring isotopes. This sequence is completely different from that reported previously. A comparison of the him band in I-109 with those in heavier iodines shows that I-109 continues the trend of decreasing quadrupole deformation with decreasing neutron number. [S0556-2813(99)50804-2]. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. RP Yu, CH (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 30 TC 24 Z9 24 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 APR PY 1999 VL 59 IS 4 BP R1834 EP R1838 DI 10.1103/PhysRevC.59.R1834 PG 5 WC Physics, Nuclear SC Physics GA 188HJ UT WOS:000079840500002 ER PT J AU Apanasevich, L Balazs, C Bromberg, C Huston, J Maul, A Tung, WK Kuhlmann, S Owens, J Begel, M Ferbel, T Ginther, G Slattery, P Zielinski, M AF Apanasevich, L Balazs, C Bromberg, C Huston, J Maul, A Tung, WK Kuhlmann, S Owens, J Begel, M Ferbel, T Ginther, G Slattery, P Zielinski, M TI k(T) effects in direct-photon production SO PHYSICAL REVIEW D LA English DT Article ID HIGH TRANSVERSE-MOMENTUM; TO-BACK JETS; 280 GEV/C; CROSS-SECTIONS; PARTON DISTRIBUTIONS; INELASTIC-SCATTERING; PROTON INTERACTIONS; GLUON DISTRIBUTION; HADRON COLLIDERS; BOSON PRODUCTION AB We discuss the phenomenology of initial-state parton-k(T) broadening in direct-photon production and related processes in hadron collisions. After a brief summary of the theoretical basis for a Gaussian-smearing approach, we present a systematic study of recent results on fixed-target and collider direct-photon production, using complementary data on diphoton and pion production that provide empirical guidance on the required amount of k(T) broadening. This approach provides a consistent description of the observed pattern of deviation of next-to-leading order QCD calculations relative to the direct-photon data, and accounts for the shape and normalization difference between fixed-order perturbative calculations and the data. We also discuss the uncertainties in this phenomenological approach, the implications of these results on the extraction of the gluon distribution of the nucleon, and the comparison of our findings to recent related work. [S0556-2821(99)03805-9]. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. RP Apanasevich, L (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 62 TC 116 Z9 117 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 APR 1 PY 1999 VL 59 IS 7 AR 074007 DI 10.1103/PhysRevD.59.074007 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900014 ER PT J AU Berger, EL Klasen, M Tait, T AF Berger, EL Klasen, M Tait, T TI Scale dependence of squark and gluino production cross sections SO PHYSICAL REVIEW D LA English DT Article ID HADRON COLLIDERS; PERTURBATIVE QCD; PYTHIA-5.7 AB We investigate the choice of the renormalization and factorization scales for the production of squarks and gluinos at the Fermilab Tevatron collider as a function of the produced sparticle masses. We determine a scale to be used in leading-order perturbative QCD calculations optimized such that the normalization of the next-to-leading order cross section is reproduced. Use of this optimal scale permits at least a partial implementation of next-to-leading order contributions in leading order Monte Carlo simulations. We provide next-to-leading order predictions of the production cross sections for pairs of supersymmetric particles at the hadronic center-of-mass energy 2 TeV. [S0556-2821(99)02707-1]. C1 Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. Michigan State Univ, E Lansing, MI 48824 USA. RP Berger, EL (reprint author), Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. NR 12 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 APR 1 PY 1999 VL 59 IS 7 AR 074024 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900031 ER PT J AU Chanowitz, MS AF Chanowitz, MS TI Higgs boson mass constraints from precision data and direct searches SO PHYSICAL REVIEW D LA English DT Article ID STANDARD MODEL; PHYSICS AB Two of the nine measurements of sin(2)theta (lepton)(eff), the effective weak interaction mixing angle, are found to be in significant conflict with the direct search limits for the standard model (SM) Higgs boson. Using a scale factor method, analogous to one used by the Particle Data Group, we assess the possible effect of these discrepancies on the SM fit of the Higgs boson mass. The scale factor fits increase the value of sin(2)theta(eff)(lepton) by as much as two standard deviations. The central value of the Higgs boson mass increases as much as a factor of 2, to similar or equal to 200 GeV, and the 95% confidence level upper limit increases to as much as 750 GeV. The scale factor is based not simply on the discrepant measurements, as was the case in-a previous analysis, but on an aggregate goodness-of-fit confidence level for the nine measurements and the limit. The method is generally applicable to fits in which one or more of a collection of measurements are in conflict with a physical boundary or limit. In the present context, the results suggest caution in drawing conclusions about the Higgs boson mass from the existing data. [S0556-2821(99)03707-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. EM chanowitz@lbl.gov NR 17 TC 8 Z9 8 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 APR 1 PY 1999 VL 59 IS 7 AR 073005 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900007 ER PT J AU Chivukula, RS Dobrescu, BA Georgi, H Hill, CT AF Chivukula, RS Dobrescu, BA Georgi, H Hill, CT TI Top quark seesaw theory of electroweak symmetry breaking SO PHYSICAL REVIEW D LA English DT Article ID TOPCOLOR-ASSISTED TECHNICOLOR; STANDARD MODEL; MASS; CONDENSATION; CONSTRAINTS AB We study electroweak symmetry breaking involving the seesaw mechanism of quark condensation. These models produce a composite Higgs boson involving the left-handed top quark, yet the top quark mass arises naturally at the observed scale: We describe a schematic model which illustrates the general dynamical ideas. We also consider a generic Low-energy effective theory which includes several composite scalars, and we use the effective potential formalism to compute their spectrum. We develop a more detailed model in which certain features of the schematic model are replaced by additional dynamics. [S0556-2821 (99)02105-0]. C1 Boston Univ, Dept Phys, Boston, MA 02215 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Chicago, Chicago, IL 60637 USA. RP Chivukula, RS (reprint author), Boston Univ, Dept Phys, 590 Commonwealth Ave, Boston, MA 02215 USA. EM sekhar@bu.edu; bdob@fnal.gov; georgi@physics.harvard.edu; hill@fnal.gov RI Chivukula, R. Sekhar/C-3367-2012 OI Chivukula, R. Sekhar/0000-0002-4142-1077 NR 21 TC 222 Z9 222 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 APR 1 PY 1999 VL 59 IS 7 AR 075003 DI 10.1103/PhysRevD.59.075003 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900042 ER PT J AU Gordon, LE Ramsey, GP AF Gordon, LE Ramsey, GP TI Spin structure of the proton and large p(T) processes in polarized pp collisions SO PHYSICAL REVIEW D LA English DT Article ID PROMPT PHOTON PRODUCTION; PARTON DISTRIBUTIONS; LEADING ORDER; SPLITTING FUNCTIONS; JET PRODUCTION; DELTA-G; NUCLEON; HERA-(N)OVER-RIGHT-ARROW; QCD AB QCD motivated polarized parton distributions, evolved directly in x space, are used to predict rates for prompt photon and jet production at BNL RHIC and DESY HERA-(N) over right arrow center of mass energies. Various scenarios for the polarized gluon distributions are considered and compared, and the possibility of using large p(T) processes in polarized pp collision experiments to choose between them is analyzed. [S0556-2821(99)05405-3]. C1 Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. Hampton Univ, Newport News, VA 23606 USA. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. Loyola Univ, Chicago, IL 60626 USA. RP Gordon, LE (reprint author), Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. EM lgordon@cebaf.gov; gpr@hep.anl.gov NR 27 TC 10 Z9 10 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 APR 1 PY 1999 VL 59 IS 7 AR 074018 DI 10.1103/PhysRevD.59.074018 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900025 ER PT J AU Hoang, AH Ligeti, Z Manohar, AV AF Hoang, AH Ligeti, Z Manohar, AV TI B decays in the upsilon expansion SO PHYSICAL REVIEW D LA English DT Article ID QUARK EFFECTIVE THEORY; SEMILEPTONIC BRANCHING RATIO; HEAVY-QUARK; WEAK DECAYS; PERTURBATION-THEORY; QCD CORRECTIONS; NONPERTURBATIVE CORRECTIONS; QUANTUM CHROMODYNAMICS; INCLUSIVE BEAUTY; PHOTON SPECTRUM AB Theoretical predictions for B decay rates are rewritten in terms of the Y(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. The theoretical consistency of this expansion is shown both at low and high orders. Our method improves the behavior of the perturbation series for semileptonic and nonleptonic inclusive decay modes, as well as for exclusive decay form factors. The results are applied to the determination of the semileptonic B branching ratio, charm counting, the ratio of B-->X tau (v) over bar and B-->Xe (v) over bar decay rates, and form factor ratios in B-->D*e (v) over bar decay. We also comment on why it is not possible to separate perturbative and nonperturbative effects in QCD. [S0556-2821(99)03207-5]. C1 CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Fermi Natl Accelerator Lab, Theory Grp, Batavia, IL 60510 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Hoang, AH (reprint author), CERN, Div Theory, CH-1211 Geneva 23, Switzerland. NR 68 TC 138 Z9 138 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 APR 1 PY 1999 VL 59 IS 7 AR 074017 DI 10.1103/PhysRevD.59.074017 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900024 ER PT J AU Kidonakis, N Vogt, R AF Kidonakis, N Vogt, R TI Soft-gluon resummation for heavy quark production in hadronic collisions SO PHYSICAL REVIEW D LA English DT Article ID PRODUCTION CROSS-SECTION; QCD HARD SCATTERING; P(P)OVER-BAR COLLISIONS; THRESHOLD RESUMMATION; DISTRIBUTIONS; LOGARITHMS; SERIES AB We discuss the heavy quark production cross section near partonic threshold in hadronic collisions, including the resummation of leading and next-to-leading logarithms arising from soft gluon emission. We show how to handle the complications due to the non-universal non-leading logarithms. We give analytical results for the q (q) over bar partonic subprocess and numerical results in the DIS scheme for top quark production at the Fermilab Tevatron where the q (q) over bar channel dominates. [S0556-2821(99)01707-5]. C1 Univ Edinburgh, Dept Phys & Astron, Edinburgh EH9 3JZ, Midlothian, Scotland. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Livermore, CA 95616 USA. RP Kidonakis, N (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. NR 41 TC 18 Z9 18 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 APR 1 PY 1999 VL 59 IS 7 AR 074014 DI 10.1103/PhysRevD.59.074014 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900021 ER PT J AU Lee, FX Leinweber, DB AF Lee, FX Leinweber, DB TI Light hadron spectroscopy on coarse lattices with O(a(2)) mean-field-improved actions SO PHYSICAL REVIEW D LA English DT Article ID WILSON FERMIONS; GAUGE-THEORIES; MASSES; SIMULATIONS; COMPUTERS; SPECTRUM; SCALE; QCD AB The masses and dispersions of light hadrons are calculated in lattice QCD using an O(a(2)) tadpole-improved gluon action and an O(a(2)) tadpole-improved next-nearest-neighbor fermion action originally proposed by Hamber and Wu. Two lattices of constant volume with lattice spacings of approximately 0.40 fm and 0.24 fm are considered. The results reveal some scaling violations at the coarser lattice spacing on the order of 5%. At the finer lattice spacing, the nucleon to rho mass ratio reproduces state-of-the-art results using unimproved actions. Good dispersion and rotational invariance up to momenta of pa similar or equal to 1 are alsb found. The relative merit of alternative choices for improvement operators is assessed through close comparisons with other plaquette-based tadpole-improved actions. [S0556-2821(99)03807-2]. C1 George Washington Univ, Dept Phys, Ctr Nucl Studies, Washington, DC 20052 USA. Jefferson Lab, Newport News, VA 23606 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ Adelaide, Dept Phys & Math Phys, Adelaide, SA 5005, Australia. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP George Washington Univ, Dept Phys, Ctr Nucl Studies, Washington, DC 20052 USA. EM fxlee@gwu.edu; dleinweb@physics.adelaide.edu.au RI Leinweber, Derek/J-6705-2013 OI Leinweber, Derek/0000-0002-4745-6027 NR 37 TC 13 Z9 13 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 APR 1 PY 1999 VL 59 IS 7 AR 074504 DI 10.1103/PhysRevD.59.074504 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900037 ER PT J AU Lewis, R Mobed, N AF Lewis, R Mobed, N TI Isospin violation and the proton's neutral weak magnetic form factor SO PHYSICAL REVIEW D LA English DT Article ID CHIRAL PERTURBATION-THEORY; PION-NUCLEON SCATTERING; SYMMETRY-BREAKING; EXPANSION AB The effects of isospin violation on the neutral weak magnetic form factor of the proton are studied using two-flavor chiral perturbation theory. The first nonzero contributions appear at O(p(4)) in the small-momentum expansion, and the O(p(5)) corrections are also calculated. The leading contributions from an explicit Delta(1232) isomultiplet are included as well. At such a high order in the chiral expansion, one might have expected a large number of unknown parameters to contribute. However, it is found that no unknown parameters can appear within loop diagrams, and a single tree-level counterterm at O(p(4)) is sufficient to absorb all divergences. The momentum dependence of the neutral weak magnetic form factor is independent of the counterterm, and is consistent with previous quark model estimates. Removal of higher-energy physics from the counterterm leaves a pion-cloud contribution to the form factor which is approximately 0.02 nuclear magnetons at q(2) = 0. [S0556-2821(99)02407-8]. C1 Jefferson Lab, Newport News, VA 23606 USA. Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada. RP Lewis, R (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 28 TC 12 Z9 12 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 APR 1 PY 1999 VL 59 IS 7 AR 073002 DI 10.1103/PhysRevD.59.073002 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900004 ER PT J AU Maltoni, F Petrelli, A AF Maltoni, F Petrelli, A TI Color-octet effects in radiative Y decays SO PHYSICAL REVIEW D LA English DT Article ID DIRECT PHOTON SPECTRUM; TO-LEADING ORDER; QUARKONIA PRODUCTION; LEPTONIC DECAYS; QCD; UPSILON; PHOTOPRODUCTION; FRAGMENTATION; ANNIHILATION; COLLISIONS AB We investigate the effects of color-octet contributions to the radiative Y decay within the Bodwin, Braaten, and Lepage nonrelativistic QCD (NRQCD) framework. We compute the short-distance coefficients at next-to-leading order (NLO) in a(s) for the most relevant color-octet intermediate states and consider photons coming both from the coupling to hard processes ("direct") and by collinear emission from light quarks ("fragmentation"). An estimate for the nonperturbative matrix elements which enter in the final result is then obtained. By comparing the NRQCD prediction at NLO for total decay rates with the experimental data, it is found that the nonperturbative parameters must be smaller than expected from the naive scaling rules of NRQCD. Nevertheless, color-octet contributions to the shape of the photon spectrum turn out to be significant. [S0556-2821(99)02705-8]. C1 CERN, Div TH, CH-1211 Geneva, Switzerland. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. Univ Pisa, Dipartimento Fis, Pisa, Italy. Sez INFN, Pisa, Italy. RP Maltoni, F (reprint author), CERN, Div TH, CH-1211 Geneva, Switzerland. EM fabio.maltoni@cern.ch; petrelli@hep.anl.gov NR 35 TC 28 Z9 28 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 1 PY 1999 VL 59 IS 7 AR 074006 DI 10.1103/PhysRevD.59.074006 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900013 ER PT J AU Oller, JA Oset, E Pelaez, JR AF Oller, JA Oset, E Pelaez, JR TI Meson-meson interactions in a nonperturbative chiral approach SO PHYSICAL REVIEW D LA English DT Article ID SYMMETRY-BREAKING SECTOR; COUPLED-CHANNEL ANALYSIS; PERTURBATION-THEORY; PI-SCATTERING; SCALAR MESONS; PHASE-SHIFT; GEV-C; DISPERSION; F(0)(980); A(0)(980) AB A nonperturbative method which combines constraints from chiral symmetry breaking and coupled channel unitarity is used to describe the meson-meson interaction up to about 1.2 GeV. The approach uses the O(p(2)) and O(p(4)) chiral Lagrangians. The seven free parameters of the O(p(4)) Lagrangian are fitted to the data. The results are in good agreement with a vast amount of experimental analyses. The amplitudes develop poles in the complex plane corresponding to the f(0,) a(0), rho, K-*, phi, sigma and kappa resonances, the latter two being very broad. The total and partial decay widths of the resonances are also well reproduced. Further extensions and applications of this chiral nonperturbative scheme are also discussed. [S0556-2821(99)05003-1]. C1 Univ Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46100 Valencia, Spain. Univ Valencia, CSIC, Ctr Mixto, IFIC, E-46100 Valencia, Spain. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Oller, JA (reprint author), Univ Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46100 Valencia, Spain. EM oller@condor.ific.uv.es; oset@condorl.ific.uv.es; pelaez@eucmax.sim.ucm.es RI Pelaez, Jose/K-9767-2014 OI Pelaez, Jose/0000-0003-0737-4681 NR 59 TC 431 Z9 431 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 APR 1 PY 1999 VL 59 IS 7 AR 074001 DI 10.1103/PhysRevD.59.074001 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900008 ER PT J AU Robertson, DG Swanson, ES Szczepaniak, AP Ji, CR Cotanch, SR AF Robertson, DG Swanson, ES Szczepaniak, AP Ji, CR Cotanch, SR TI Renormalized effective QCD Hamiltonian: Gluonic sector SO PHYSICAL REVIEW D LA English DT Article ID CHIRAL SYMMETRY; FIELD AB Extending previous QCD Hamiltonian studies, we present a new renormalization procedure which generates an effective Hamiltonian for the gluon sector. The formulation is in the Coulomb gauge where the QCD Hamiltonian is renormalizable and the Gribov problem can be resolved. We utilize elements of the Glazek and Wilson regularization method but now introduce a continuous cut-off procedure which eliminates non-local counterterms. The effective Hamiltonian is then derived to second order in the strong coupling constant. The resulting renormalized Hamiltonian provides a realistic starting point for approximate many-body calculations of hadronic properties for systems with explicit gluon degrees of freedom. [S50556-2821(99)01807-X]. C1 N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. Jefferson Lab, Newport News, VA 23606 USA. Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. Indiana Univ, Ctr Nucl Theory, Bloomington, IN 47405 USA. RP N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. RI Ji, Chueng/J-2623-2013 NR 13 TC 21 Z9 21 U1 0 U2 2 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 APR 1 PY 1999 VL 59 IS 7 AR 074019 DI 10.1103/PhysRevD.59.074019 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 181WX UT WOS:000079466900026 ER PT J AU Liu, YM Ecke, RE AF Liu, YM Ecke, RE TI Nonlinear traveling waves in rotating Rayleigh-Benard convection: Stability boundaries and phase diffusion SO PHYSICAL REVIEW E LA English DT Article ID ECKHAUS INSTABILITY; HOPF-BIFURCATION; PATTERN SELECTION; FLOW; STATES; MODES AB We present experimental measurements of a sidewall traveling wave in rotating Rayleigh-Benard convection. The fluid, water with Prandtl number about 6.3, was confined in a 1-cm-high cylindrical cell with radius-to-height ratio Gamma=5. We used simultaneous optical-shadowgraph, heat-transport, and local temperature measurements to determine the stability and characteristics of the traveling-wave state for dimensionless rotation rates 60 (b) over bar b)/BR(h(0) --> tau(+)tau(-)) of the Higgs boson h(0) may usefully differentiate between the Higgs sectors of the Minimal Supersymmetric Standard Model (MSSM) and non-supersymmetric models such as the Standard Model or its two Higgs doublet extensions. Although at tree level R-b/tau is the same in all these models, only in the MSSM can it receive a large radiative correction, for moderate to large values of the parameter tan beta. Such large corrections are motivated in supersymmetric unified schemes wherein the Yukawa couplings of the b-quark and the tau-lepton are equal at the unification scale; otherwise the b-quark mass prediction is too large by 15-30% for most of parameter space. Thus accurate measurements of the Higgs branching ratios can probe physics at the unification scale. The branching ratio of h(o) into charm quarks, as well as of the other Higgs bosons (H-o,A(o)) into (b) over bar b, tau(+)tau(-), (c) over bar c can provide additional information about the supersymmetric nature of the Higgs sector. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Babu, KS (reprint author), Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. NR 23 TC 70 Z9 70 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 APR 1 PY 1999 VL 451 IS 1-2 BP 77 EP 85 DI 10.1016/S0370-2693(99)00204-X PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 187EP UT WOS:000079774200012 ER PT J AU Mrenna, S Womersley, J AF Mrenna, S Womersley, J TI Can a light technipion be discovered at the Tevatron if it decays to two gluons? SO PHYSICS LETTERS B LA English DT Article ID TOPCOLOR-ASSISTED TECHNICOLOR; LOW-SCALE TECHNICOLOR; CHIRAL HIERARCHIES; SYMMETRY-BREAKING; STANDARD MODEL; CONDENSATE; HYPERCOLOR; PHYSICS AB In multiscale and topcolor-assisted models of walking technicolor, light, spin-one technihadrons can exist with masses of a few hundred GeV; they are expected to decay as rho(T) --> W pi(T). For M-rho T similar or equal to 200 GeV and M-pi T similar or equal to 100 GeV, the process --> rho(T) --> W pi(T) has a cross section of about a picobarn at the Tevatron. We demonstrate the detectability of this process with simulations appropriate to Run Il conditions, for the challenging case where the technipion decays dominantly into two gluons. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Davis, CA 95616 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Mrenna, S (reprint author), Univ Calif Davis, Davis, CA 95616 USA. OI Mrenna, Stephen/0000-0001-8731-160X NR 27 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 APR 1 PY 1999 VL 451 IS 1-2 BP 155 EP 160 DI 10.1016/S0370-2693(99)00199-9 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 187EP UT WOS:000079774200023 ER PT J AU Duan, JQ Holm, DD Li, KT AF Duan, JQ Holm, DD Li, KT TI Variational methods and nonlinear quasigeostrophic waves SO PHYSICS OF FLUIDS LA English DT Article ID NAVIER-STOKES EQUATIONS; STABILITY THEOREM; ROTATING FLUIDS; 3D EULER; INTEGRABILITY; REGULARITY; MODEL; FLOW AB In this paper, we discuss zonally periodic steady quasigeostrophic waves in a beta-plane channel, by using variational methods. A class of steady quasigeostrophic waves are determined by the potential vorticity field profile, g(.), which is a function of the stream function. We show that zonally periodic steady quasigeostrophic waves exist when the bottom topography and the potential vorticity field are bounded. We also show that these waves are unique if, in addition, the potential vorticity field profile is increasing and passes through the origin. Finally, we demonstrate that the zonal periodic wave in the case with g(psi)= arctan(psi) is nonlinearly stable in the sense of Liapunov, under a boundedness condition for the potential vorticity field, or equivalently, under suitable conditions on the bottom topography, beta parameter, and zonal period T. (C) 1999 American Institute of Physics. [S1070-6631(99)00804-1]. C1 Clemson Univ, Dept Math Sci, Clemson, SC 29634 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. Xian Jiao Tong Univ, Res Ctr Appl Math, Xian 710049, Peoples R China. Univ Cambridge, Isaac Newton Inst Math Sci, Cambridge CB2 1TN, England. RP Duan, JQ (reprint author), Clemson Univ, Dept Math Sci, Clemson, SC 29634 USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 20 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD APR PY 1999 VL 11 IS 4 BP 875 EP 879 DI 10.1063/1.869959 PG 5 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 178YZ UT WOS:000079297900013 ER PT J AU Berger, RL Lefebvre, E Langdon, AB Rothenberg, JE Still, CH Williams, EA AF Berger, RL Lefebvre, E Langdon, AB Rothenberg, JE Still, CH Williams, EA TI Stimulated Raman and Brillouin scattering of polarization-smoothed and temporally smoothed laser beams SO PHYSICS OF PLASMAS LA English DT Article ID INHOMOGENEOUS-PLASMA; IGNITION; TARGETS; LIGHT; NOISE AB Control of filamentation and stimulated Raman and Brillouin scattering is shown to be possible by use of both spatial and temporal smoothing schemes. The spatial smoothing is accomplished by the use of phase plates [Y. Kato and K. Mima, Appl. Phys. 329, 186 (1982)] and polarization smoothing [Lefebvre et al., Phys. Plasmas 5, 2701 (1998)] in which the plasma is irradiated with two orthogonally polarized, uncorrelated speckle patterns. The temporal smoothing considered here is smoothing by spectral dispersion [Skupsky et al., J. Appl. Phys. 66, 3456 (1989)] in which the speckle pattern changes on the laser coherence time scale. At the high instability gains relevant to laser fusion experiments, the effect of smoothing must include the competition among all three instabilities. (C) 1999 American Institute of Physics. [S1070-664X(99)02804-9]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Berger, RL (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Lefebvre, Erik/B-9835-2009 NR 17 TC 29 Z9 29 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1043 EP 1047 DI 10.1063/1.873713 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100001 ER PT J AU Mattor, N AF Mattor, N TI Local approximation for the phase velocity transform SO PHYSICS OF PLASMAS LA English DT Article AB A recent paper [N. Mattor, Phys. Plasmas 5, 1822 (1998)] introduced the phase velocity transform. This was used to derive closed fluid moment equations from a collisionless kinetic equation. Here, a local approximation for this transform is introduced, which allows much simpler calculation. A local approximation to the Hilbert transform is also given. (C) 1999 American Institute of Physics. [S1070-664X(99)01204-5]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Mattor, N (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 6 TC 3 Z9 3 U1 0 U2 1 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 APR PY 1999 VL 6 IS 4 BP 1059 EP 1064 DI 10.1063/1.873353 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100004 ER PT J AU Mattor, N AF Mattor, N TI Collisionless fluid equations: Lagrangian, Eulerian, and local forms SO PHYSICS OF PLASMAS LA English DT Article AB A recent paper [N. Mattor, Phys. Plasmas 5, 1822 (1998)] derived closed fluid moment equations from a collisionless kinetic equation. These fluid equations retain the effects of linear and nonlinear wave-particle resonances, traditionally thought to require kinetic equations. This paper gives three methods to calculate this term. In the Lagrangian form, the components making up the closure term are constant along phase rays, and so can be traced from the initial time. The Eulerian form evolves the components on a constant spatial grid and so does not require explicit calculation of phase rays. The local approximation is a heuristic method of approximating global integrals based on local gradients, and offers significant simplification over the other two methods. (C) 1999 American Institute of Physics. [S1070-664X(99)01304-X]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Mattor, N (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 10 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1065 EP 1071 DI 10.1063/1.873381 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100005 ER PT J AU Kolesnichenko, YI Lutsenko, VV White, RB Yakovenko, YV Zweben, SJ AF Kolesnichenko, YI Lutsenko, VV White, RB Yakovenko, YV Zweben, SJ TI Distributions of alpha particles escaping to the wall during sawtooth oscillations in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID FAST-ION TRANSPORT; NEUTRON EMISSION; TFTR; REDISTRIBUTION; JET; DISCHARGES; CRASHES AB It has been observed experimentally in deuterium-tritium shots of the Tokamak Fusion Test Reactor (TFTR) [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)] that crashes of sawtooth oscillations may result in very inhomogeneous flux of alpha particles to the wall. To explain this phenomenon, both theoretical analysis and numerical simulation have been carried out. It is concluded that the "crash-induced prompt loss,'' i.e., the orbital loss of marginally trapped particles arising because of the crash-induced orbit transformation of circulating particles, is responsible for the flux near the bottom of the vessel, whereas the crash-induced stochastic diffusion of moderately trapped particles explains the large signal near the equatorial plane of the torus. The calculated poloidal distributions of the integral alpha flux are in reasonable agreement with experimental data. The energy spectrum of the escaping particles has also been calculated, which can be used for diagnostics of the crash type. (C) 1999 American Institute of Physics. [S1070-664X(99)02304-6]. C1 Inst Nucl Res, Ctr Sci, UA-252650 Kyiv, Ukraine. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Kolesnichenko, YI (reprint author), Inst Nucl Res, Ctr Sci, UA-252650 Kyiv, Ukraine. RI White, Roscoe/D-1773-2013; OI White, Roscoe/0000-0002-4239-2685; Yakovenko, Yuriy/0000-0002-3499-5275 NR 20 TC 7 Z9 7 U1 0 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 APR PY 1999 VL 6 IS 4 BP 1117 EP 1130 DI 10.1063/1.873358 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100011 ER PT J AU Heidbrink, WW Ruskov, E Carolipio, EM Fang, J van Zeeland, MA James, RA AF Heidbrink, WW Ruskov, E Carolipio, EM Fang, J van Zeeland, MA James, RA TI What is the "beta-induced Alfven eigenmode?" SO PHYSICS OF PLASMAS LA English DT Article ID KINETIC BALLOONING MODES; RADIAL ELECTRIC-FIELD; DIII-D; NONLINEAR EVOLUTION; ALPHA-PARTICLES; FAST IONS; TOKAMAKS; FREQUENCY; EXCITATION; PLASMA AB An instability with a lower frequency than the toroidicity-induced Alfven eigenmode was initially identified as a beta-induced Alfven eigenmode (BAE). Instabilities with the characteristic spectral features of this "BAE'' are observed in a wide variety of tokamak plasmas, including plasmas with negative magnetic shear. These modes are destabilized by circulating beam ions and they transport circulating beam ions from the plasma core. The frequency scalings of these "BAEs'' are compared to theoretical predictions for Alfven modes, kinetic ballooning modes, ion thermal velocity modes, and energetic particle modes. None of these simple theories match the data. (C) 1999 American Institute of Physics. [S1070-664X(99)00204-9]. C1 Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Heidbrink, WW (reprint author), Univ Calif Irvine, Irvine, CA 92697 USA. NR 50 TC 56 Z9 56 U1 1 U2 5 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 APR PY 1999 VL 6 IS 4 BP 1147 EP 1161 DI 10.1063/1.873359 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100013 ER PT J AU Redd, AJ Kritz, AH Bateman, G Rewoldt, G Tang, WM AF Redd, AJ Kritz, AH Bateman, G Rewoldt, G Tang, WM TI Drift mode growth rates and associated transport SO PHYSICS OF PLASMAS LA English DT Article ID BALLOONING MODES; TOROIDAL PLASMA; SIMULATIONS; TURBULENCE; STABILITY; DRIVEN AB Drift mode linear growth rates and quasilinear transport are investigated using the FULL kinetic stability code [Rewoldt et al., Phys. Plasmas 5, 1815 (1998)] and a version of the Weiland transport model [Strand et al., Nucl. Fusion 38, 545 (1998)]. It is shown that the drift mode growth rates (as well as the marginal stability temperature gradient) obtained using the FULL code are dependent on the accuracy of the equilibrium employed. In particular, when an approximate equilibrium model is utilized by the FULL code, the results can differ significantly from those obtained using a more accurate numerical equilibrium. Also investigated are the effects of including full electron physics. It is shown, using both the FULL code and the Weiland model, that the nonadiabatic (e.g., trapped) electron response produces a significant increase in the linear growth rate of the ion-temperature-gradient (ITG) driven branch of the drift instability. Other consequences of the nonadiabatic electron response include a reduction in the marginal temperature gradient for the onset of the ITG mode and an additional contribution to transport due to the excitation of the Trapped Electron Mode (TEM). Physical explanations are given for the sensitivity of the mode growth rates to the equilibrium and the nonadiabatic electron response. Finally, linear growth rates for the ITG mode computed using the FULL code are compared with growth rates obtained using the Weiland model. (C) 1999 American Institute of Physics. [S1070-664X(99)01004-6]. C1 Lehigh Univ, Dept Phys, Bethlehem, PA 18015 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Redd, AJ (reprint author), Univ Washington, Seattle, WA 98195 USA. NR 31 TC 15 Z9 15 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 APR PY 1999 VL 6 IS 4 BP 1162 EP 1167 DI 10.1063/1.873360 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100014 ER PT J AU Arndt, S Merkel, P Monticello, DA Reiman, AH AF Arndt, S Merkel, P Monticello, DA Reiman, AH TI Finite-beta equilibria for Wendelstein 7-X configurations using the Princeton Iterative Equilibrium Solver code SO PHYSICS OF PLASMAS LA English DT Article ID 3-DIMENSIONAL MAGNETOHYDRODYNAMIC EQUILIBRIA; MAGNETIC ISLANDS; MHD EQUILIBRIUM; COMPUTATION; REGIONS AB Fixed- and free-boundary equilibria for Wendelstein 7-X (W7-X) [W. Lotz et al., Plasma Physics and Controlled Nuclear Fusion Research 1990 (Proc. 13th Int. Conf. Washington, DC, 1990), (International Atomic Energy Agency, Vienna, 1991), Vol. 2, p. 603] configurations are calculated using the Princeton Iterative Equilibrium Solver (PIES) [A. H. Reiman et al., Comput. Phys. Commun., 43, 157 (1986)] to deal with magnetic islands and stochastic regions. Usually, these W7-X configurations require a large number of iterations for PIES convergence. Here, two methods have been successfully tested in an attempt to decrease the number of iterations needed for convergence. First, periodic sequences of different blending parameters are used. Second, the initial guess is vastly improved by using results of the Variational Moments Equilibrium Code (VMEC) [S. P. Hirshmann et al., Phys. Fluids 26, 3553 (1983)]. Use of these two methods have allowed verification of the Hamada condition and tendency of "self-healing'' of islands has been observed. (C) 1999 American Institute of Physics. [S1070-664X(99)03503-X]. C1 Max Planck Inst Plasma Phys, Teilinst Greifswald, EURATOM Assoc, D-17489 Greifswald, Germany. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Arndt, S (reprint author), Max Planck Inst Plasma Phys, Teilinst Greifswald, EURATOM Assoc, Walther Rathenau Str 49 A, D-17489 Greifswald, Germany. EM Stefan.Arndt@ipp.mpg.de NR 30 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1246 EP 1252 DI 10.1063/1.873367 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100021 ER PT J AU Watanabe, TH Hayashi, T Sato, T Yamada, M Ji, H AF Watanabe, TH Hayashi, T Sato, T Yamada, M Ji, H TI Modeling of magnetic island formation in magnetic reconnection experiment SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOHYDRODYNAMIC SIMULATION; LABORATORY PLASMA; CONFIGURATION; RELAXATION; HELICITY AB Formation of a magnetic island found in the Magnetic Reconnection Experiment (MRX) [M. Yamada, H. Ji, S. Hsu, et al., Phys. Plasmas 4, 1936 (1997)] is investigated by a magnetohydrodynamic (MHD) relaxation theory and a numerical simulation. In the cohelicity injection with a mean toroidal field, the growing process of the island into a spheromak-type configuration is explained by quasistatic transition of the force-free and minimum energy state to a state with larger normalized helicity. It also turns out that no magnetic island would be generated in the counterhelicity case. The MHD simulation with inhomogeneous electric resistivity agrees with experimental results, which clearly shows formation and growth of the magnetic island in a diffusion region where the reconnection takes place. (C) 1999 American Institute of Physics. [S1070-664X(99)03904-X]. C1 Natl Inst Fus Sci, Theory & Comp Simulat ctr, Gifu 5095292, Japan. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Watanabe, TH (reprint author), Natl Inst Fus Sci, Theory & Comp Simulat ctr, Gifu 5095292, Japan. NR 17 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1253 EP 1257 DI 10.1063/1.873368 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100022 ER PT J AU Sanford, TWL Mock, RC Nash, TJ Whitney, KG Pulsifer, PE Apruzese, JP Mosher, D Peterson, DL Haines, MG AF Sanford, TWL Mock, RC Nash, TJ Whitney, KG Pulsifer, PE Apruzese, JP Mosher, D Peterson, DL Haines, MG TI Systematic trends in x-ray emission characteristics of variable-wire-number, fixed-mass, aluminum-array, Z-pinch implosions SO PHYSICS OF PLASMAS LA English DT Article ID SIMILAR ATOMIC NUMBERS; HIGH-POWER; PLASMAS; DIAGNOSTICS; ELEMENTS; SATURN AB Increasing the number of wires an order of magnitude from 10 to almost 200 while simultaneously fixing the total wire mass in annular aluminum-wire-array Z-pinch implosions on the 20 TW Saturn generator [Proceedings of the 6th International IEEE Pulsed Power Conference (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 1987), p. 310] demonstrates two separate power-law trends in the measured x-ray characteristics as a function of the initial interwire gap (g). These trends are approximately independent of the array radius. When g decreases from similar to 6 to 0.4 mm, the peak total radiated power increases by a factor of 20 and the total energy by a factor of 2. There is a more rapid increase in peak power and energy radiated as g decreases for gaps greater than;2 mm. This increase is related to a measured decrease in precursor plasma and to a calculated decreased sensitivity of the implosion to azimuthal asymmetries that occurs when individual wire plasmas begin to merge following their vaporization. The substantial increase in power arises from an inferred increase in plasma compression and can be correlated with an almost linear reduction in the calculated effective thickness of the plasma annulus near stagnation as g decreases. (C) 1999 American Institute of Physics. [S1070-664X(99)00404-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. USN, Res Lab, Radiat Hydrodynam Branch, Washington, DC 20375 USA. USN, Res Lab, Pulsed Power Phys Branch, Washington, DC 20375 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. RP Sanford, TWL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 54 TC 31 Z9 39 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1270 EP 1293 DI 10.1063/1.873370 PG 24 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100024 ER PT J AU Russell, DA DuBois, DF Rose, HA AF Russell, DA DuBois, DF Rose, HA TI Nonlinear saturation of stimulated Raman scattering in laser hot spots SO PHYSICS OF PLASMAS LA English DT Article ID STRONG LANGMUIR TURBULENCE; PARAMETRIC-INSTABILITIES; HOHLRAUM PLASMAS; BRILLOUIN; DECAY; SPACE; FLOW AB Two-dimensional simulation studies are reported of the nonlinear development of stimulated Raman scattering (SRS) from a compact laser hot spot using a reduced model, which includes saturation by pump depletion, Langmuir wave decay cascades, Langmuir wave collapse, and ponderomotive density profile modification. The needle-like intensity distribution in a speckle arising from a random phase plate processed laser beam promotes backscatter SRS. The dependence of the saturated reflectivity and (the comparable in magnitude! absorptivity, on ion acoustic wave and Langmuir wave damping, laser power, electron density, and temperature is studied. There are regimes in which the ponderomotive potential (as well as the Ohmic dissipation! of the induced Langmuir turbulence exceeds that of the localized laser pump. The results support the conclusion that the Langmuir wave Landau damping must be determined by an electron velocity distribution modified by quasilinear and Ohmic heating to account for SRS observed at low densities and high temperatures. (C) 1999 American Institute of Physics. [S1070-664X(99)00804-6]. C1 Lodestar Res Corp, Boulder, CO 80301 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Russell, DA (reprint author), Lodestar Res Corp, 2400 Cent Ave,P-5, Boulder, CO 80301 USA. EM dave@lodestar.com NR 41 TC 77 Z9 77 U1 1 U2 8 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 APR PY 1999 VL 6 IS 4 BP 1294 EP 1317 DI 10.1063/1.873371 PG 24 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100025 ER PT J AU Brizard, AJ Wurtele, JS AF Brizard, AJ Wurtele, JS TI Lagrangian formulation for neutrino-plasma interactions SO PHYSICS OF PLASMAS LA English DT Article ID DENSE-PLASMAS; GENERATION AB A Lagrangian formalism is used to derive coupled nonlinear equations for collective interactions between an intense neutrino flux and a relativistic cold plasma fluid with multiple particle species. In order to focus on the self-consistent (collective) treatment of neutrino-plasma interactions, quantum effects are ignored throughout and the (spinless) neutrinos are represented by a complex-valued Klein-Gordon scalar field. Through the application of Noether's method, the conservation laws for energy, momentum and wave action are derived explicitly. The transfer of energy, momentum and wave action between the neutrinos and the electromagnetic-plasma is discussed in the context of astrophysical applications (e.g., type II supernova explosions). (C) 1999 American Institute of Physics. [S1070-664X(99)01104-0]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Brizard, AJ (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI wurtele, Jonathan/J-6278-2016; OI wurtele, Jonathan/0000-0001-8401-0297; Brizard, Alain/0000-0002-0192-6273 NR 21 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1323 EP 1328 DI 10.1063/1.873373 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100027 ER PT J AU Daughton, W AF Daughton, W TI The unstable eigenmodes of a neutral sheet SO PHYSICS OF PLASMAS LA English DT Article ID HYBRID-DRIFT INSTABILITY; 2-DIMENSIONAL MAGNETOTAIL EQUILIBRIA; PLASMA SHEET; COLLISIONLESS RECONNECTION; PARTICLE SIMULATIONS; ELECTRON DYNAMICS; KINK INSTABILITY; TEARING MODE; STABILITY; SUBSTORM AB The linear stability of a Harris current sheet is examined using the Vlasov description for both ions and electrons. Orbit integrals are treated numerically using the exact particle orbits and including the global structure of the perturbation inside the integral. Both electromagnetic and electrostatic contributions to the field perturbation are retained and the eigenvalue problem for the system of integro-differential equations is solved using a Hermite expansion of the eigenfunction. For the tearing mode, results are in excellent agreement with established theory. For the recently discovered kink mode, results are consistent with kinetic simulations at low mass ratio m(i)/m(e) less than or equal to 16. However, in the limit of realistic electron mass, the growth rate of the kink mode is substantially reduced in contrast to results from kinetic simulations. It is demonstrated that a background population may dramatically alter the growth rate of the kink mode at realistic values of the mass ratio. This result may have relevance to the stability of the Earth's geomagnetic tail. (C) 1999 American Institute of Physics. [S1070-664X(99)02404-0]. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Daughton, W (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM daughton@lanl.gov RI Daughton, William/L-9661-2013 NR 49 TC 126 Z9 126 U1 0 U2 19 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD APR PY 1999 VL 6 IS 4 BP 1329 EP 1343 DI 10.1063/1.873374 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 179WY UT WOS:000079354100028 ER PT J AU Bouzar, H Jones, JB Stall, RE Louws, FJ Schneider, M Rademaker, JLW de Bruijn, FJ Jackson, LE AF Bouzar, H Jones, JB Stall, RE Louws, FJ Schneider, M Rademaker, JLW de Bruijn, FJ Jackson, LE TI Multiphasic analysis of xanthomonads causing bacterial spot disease on tomato and pepper in the Caribbean and Central America: Evidence for common lineages within and between countries SO PHYTOPATHOLOGY LA English DT Article ID CAMPESTRIS PV-VESICATORIA; STRAINS; RACE; RESISTANCE; FIELDS; COPPER; PCR; AVIRULENCE; PATHOVARS; PROFILES AB Four hundred thirty-three xanthomonad strains isolated fi om tomato or pepper plants from 32 different fields in four Caribbean and Central American countries were screened for the ability to hydrolyze starch and sodium polypectate and for resistance to copper and streptomycin. Of these, 95 representative strains were further characterized by various phnetic tests, and 63 of these strains were then analyzed by genomic fingerprinting. Most of the strains (>90%) were tolerant to copper. However, there was much more variability in sensitivity to streptomycin. All strains in Guadeloupe and 93% of the strains in Barbados were sensitive to streptomycin. The majority of strains were typical Xanthomonas campestris pv. vesicatoria group A strains. in Barbados, however, a unique group of strains was identified that was serologically similar to group A strains but was amylolytic. These strains were designated Al. The occurrence of X. campestris pv. vesicatoria group B strains in Central America was found to be limited to two fields in Costa Pica and one in Guatemala. No group B strains were identified in the Caribbean, in contrast to common occurrence in the central United States and in South America. T3 strains were not found in this study, despite the recent increase of such strains in Florida and Mexico. Unique strains from Costa Rica belonging to the X. gardneri group were identified. Little linkage was found among phenotypic and rep-polymerase chain reaction (rep-PCR) genomic fingerprinting profiles of the pathogens except at the species/pathovar level; strains displaying virtually identical fingerprint profiles were found to correspond to distinct races and vice versa. The rep-PCR genomic fingerprinting analyses suggest that certain lineages may have evolved or predominated in specific regions or specific countries. C1 Univ Florida, Gulf Coast Res & Educ Ctr, Bradenton, FL 34203 USA. Univ Florida, Dept Plant Pathol, Gainesville, FL 32611 USA. N Carolina State Univ, Dept Plant Pathol, Raleigh, NC 27695 USA. Michigan State Univ, DOE, Plant Res Lab, E Lansing, MI 48824 USA. Agriphi Inc, Logan, UT 84321 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. RP Jones, JB (reprint author), Univ Florida, Gulf Coast Res & Educ Ctr, Bradenton, FL 34203 USA. NR 44 TC 43 Z9 49 U1 0 U2 3 PU AMER PHYTOPATHOLOGICAL SOC PI ST PAUL PA 3340 PILOT KNOB ROAD, ST PAUL, MN 55121 USA SN 0031-949X J9 PHYTOPATHOLOGY JI Phytopathology PD APR PY 1999 VL 89 IS 4 BP 328 EP 335 DI 10.1094/PHYTO.1999.89.4.328 PG 8 WC Plant Sciences SC Plant Sciences GA 182PH UT WOS:000079507000011 PM 18944779 ER PT J AU Gao, MG Kieliszewski, MJ Lamport, DTA Showalter, AM AF Gao, MG Kieliszewski, MJ Lamport, DTA Showalter, AM TI Isolation, characterization and immunolocalization of a novel, modular tomato arabinogalactan-protein corresponding to the LeAGP-1 gene SO PLANT JOURNAL LA English DT Article ID DAUCUS-CAROTA L; SUSPENSION-CULTURED CELLS; PLASMA-MEMBRANE; SOMATIC EMBRYOGENESIS; NICOTIANA-ALATA; POLLEN-TUBE; ZEA-MAYS; MOLECULAR-CLONING; PYRUS-COMMUNIS; RICH EXTENSIN AB Arabinogalactan proteins (AGPs) are a family of hydroxyproline-rich glycoproteins implicated to function in plant growth and development. This report focuses on a novel, modular AGP found in tomato, LeAGP-1,which was predicted by DNA cloning and herein verified at the protein level as a major AGP component. LeAGP-1 was isolated from tomato suspension-cultured cells and verified to be an AGP by precipitation with (beta-D-galactosyl)(3) Yariv phenylglycoside and by amino acid composition analysis. Furthermore, LeAGP-1 was determined to correspond to LeAGP-1 clones based on three criteria: (1) amino acid composition identity, (2) amino acid sequence identity, and (3) specific immunoreactivity of glycosylated and deglycosylated LeAGP-1 with an antibody developed against the highly basic subdomain predicted from LeAGP-1 clones. The antibody was also used to immunolocalize LeAGP-1 in tomato to the cell surface of suspension-cultured cells, maturing metaxylem elements in young internodes and petioles, and stylar transmitting tissue cells. At the subcellular level, LeAGP-1 immunolocalized to the cell walls of these particular cells as well as to intercellular spaces between stylar transmitting tissue cells. LeAGP-1 now emerges as one of the most comprehensively studied AGPs in terms of (1) characterization at the genomic DNA, cDNA and protein levels, (2) known organ-specific and developmentally regulated mRNA expression patterns, (3) development of an antibody against a unique, peptide subdomain which specifically recognizes LeAGP-1 in its glycosylated and deglycosylated states, and (4) immunolocalization of a single, well-defined AGP molecule at the tissue and subcellular levels. C1 Ohio Univ, Dept Environm & Plant Biol, Mol & Cellular Biol Program, Athens, OH 45701 USA. Ohio Univ, Dept Chem, Mol & Cellular Biol Program, Athens, OH 45701 USA. Michigan State Univ, MSU DOE, Plant Res Lab, E Lansing, MI 48824 USA. RP Showalter, AM (reprint author), Ohio Univ, Dept Environm & Plant Biol, Mol & Cellular Biol Program, Athens, OH 45701 USA. EM showalte@ohio.edu NR 56 TC 53 Z9 57 U1 2 U2 12 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0960-7412 J9 PLANT J JI Plant J. PD APR PY 1999 VL 18 IS 1 BP 43 EP 55 DI 10.1046/j.1365-313X.1999.00428.x PG 13 WC Plant Sciences SC Plant Sciences GA 192JV UT WOS:000080076000005 PM 10341442 ER PT J AU Daughdrill, GW AF Daughdrill, GW TI Unfolding and disassociation of the FlgM/sigma(28) complex are thermodynamically coupled SO PROTEIN AND PEPTIDE LETTERS LA English DT Article ID ANTI-SIGMA FACTOR; C-TERMINAL HALF; SALMONELLA-TYPHIMURIUM; ESCHERICHIA-COLI; RNA-POLYMERASE; EXPORT; FLGM; SPECTROSCOPY AB FlgM and sigma(28) regulate the transcription of flagella and chemotaxis genes in E coli and S. typhimurium. In an attempt to determine the strength of the interaction between FlgM and sigma(28) thermal unfolding studies were performed using circular dichroism spectroscopy(CD). A single, cooperative, melting transition was observed for the FlgM/sigma(28) complex suggesting that unfolding and disassociation of the complex occur simultaneously. C1 Pacific NW Natl Lab, Div Macromol Struct & Dynam, Richland, WA 99352 USA. NR 16 TC 0 Z9 0 U1 1 U2 1 PU BENTHAM SCIENCE PUBL BV PI HILVERSUM PA PO BOX 1673, 1200 BR HILVERSUM, NETHERLANDS SN 0929-8665 J9 PROTEIN PEPTIDE LETT JI Protein Pept. Lett. PD APR PY 1999 VL 6 IS 2 BP 79 EP 86 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 192YU UT WOS:000080108000004 ER PT J AU Deret, S Denoroy, L Lamarine, M Vidal, R Mougenot, B Frangione, B Stevens, FJ Ronco, PM Aucouturier, P AF Deret, S Denoroy, L Lamarine, M Vidal, R Mougenot, B Frangione, B Stevens, FJ Ronco, PM Aucouturier, P TI Kappa light chain-associated Fanconi's syndrome: molecular analysis of monoclonal immunoglobulin light chains from patients with and without intracellular crystals SO PROTEIN ENGINEERING LA English DT Article DE Bence-Jones protein; human; kidney; myeloma; protein structure ID BENCE-JONES PROTEINS; TAMM-HORSFALL GLYCOPROTEIN; MULTIPLE-MYELOMA; HYPERVARIABLE REGIONS; CAST NEPHROPATHY; RENAL-FUNCTION; SEQUENCE; MODEL; ANTIBODY; OSTEOMALACIA AB Plasma cell dyscrasias may be responsible for Fanconi's syndrome, due to the toxicity of a free monoclonal kappa light chain toward kidney proximal tubules, Eight cases of Fanconi's syndrome were analyzed. We compared the structures of V kappa I. variability subgroup V domains from five cases of Fanconi's syndrome and one myeloma without renal involvement. Among Fanconi cases, four putative structures were obtained after molecular modeling by homology, and the other had previously been refined by X-ray crystallography, The complete sequences of one V kappa I, one V kappa III and N-terminal sequences of two V kappa I light chains, from patients with different forms of Fanconi's syndrome, were compared with four previously studied sequences. All three kappa chains responsible for a 'classical' form with intralysosomal crystals and a low mass myeloma, were encoded by the LCO2/O12 germline gene and had an unusual non-polar residue exposed to the solvent in the CDR-L1 loop, Of both V kappa I: light chains from patients with Fanconi's syndrome without intracellular crystals, one derived from LCO2/O12 and the other from LCO8/O18 gene. Another feature that could be related to non-crystallization was the absence of accessible side chains in the CDR-L3 loop which is known to be implicated in dimer formation. C1 Hop Necker, INSERM, U25, Clin Immunol Lab, F-75015 Paris, France. Univ Lyon 1, Lab Neuropharmacol & Neurochim, F-69373 Lyon, France. NYU, Med Ctr, Dept Pathol, New York, NY 10016 USA. INSERM, U489, F-75020 Paris, France. Hop Tenon, Div Renal, F-75020 Paris, France. Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne Natl Lab, Argonne, IL 60439 USA. RP Deret, S (reprint author), Hop Necker, INSERM, U25, Clin Immunol Lab, 161 Rue Sevres, F-75015 Paris, France. FU NIAMS NIH HHS [AR02594] NR 63 TC 39 Z9 43 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0269-2139 J9 PROTEIN ENG JI Protein Eng. PD APR PY 1999 VL 12 IS 4 BP 363 EP 369 DI 10.1093/protein/12.4.363 PG 7 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 197QY UT WOS:000080378200013 PM 10325408 ER PT J AU Blakely, EA Schimmerling, W AF Blakely, EA Schimmerling, W TI Tracy Chui-hsu Yang (1938-1998) - In memoriam SO RADIATION RESEARCH LA English DT Biographical-Item C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NASA Headquarters, Washington, DC 20546 USA. RP Blakely, EA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD APR PY 1999 VL 151 IS 4 BP 501 EP 502 PG 2 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 181MY UT WOS:000079446100017 ER PT J AU Woodruff, DL Stumpf, RP Scope, JA Paerl, HW AF Woodruff, DL Stumpf, RP Scope, JA Paerl, HW TI Remote estimation of water clarity in optically complex estuarine waters SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID MODERATELY TURBID ESTUARY; DISSOLVED ORGANIC-MATTER; NEUSE RIVER ESTUARY; ATTENUATION COEFFICIENT; NORTH-CAROLINA; OCEANIC WATERS; PHYTOPLANKTON; ABSORPTION; REFLECTANCE; QUALITY AB AVHRR satellite imagery was evaluated as a potential data source for monitoring light attenuation (K-PAR), as a measure of turbidity, in Pamlico Sound estuary, North Carolina. In situ water quality data and reflectance imagery collected on 10 different dates were used to calibrate a general optical equation relating satellite-derived reflectance (R-d), nominally R-(630 nm) to K-PAR. Additional spectral data (e.g., absorption, subsurface reflectance), related reflectance and K-PAR to changes in phytoplankton pigments, organic matter, and suspended sediments. Optically, Pamlico Sound, North Carolina is dominated by scattering from suspended sediments, whereas the tributary rivers are dominated by absorption from both dissolved and particulate organic matter. A general relationship developed between R-d and K-PAR (r(2)=0.72) in Pamlico Sound was found useful in a variety of environmental conditions; however a relationship between R-d and suspended sediment concentration was less robust, and affected by changing sediment characteristics. In the rivers, high and variable absorption in the visible wavelengths precluded development of a relationship between R-d and K-PAR. The relationship developed between R-d and K-PAR in Pamlico Sound is similar to those determined for Delaware Bay and Mobile Bay in previous studies, suggesting possible broader regional application of algorithms for coastal bays and estuaries having similar sediment characteristics, with direct application to SeaWiFS data. Published by Elsevier Science Inc. C1 NOAA, Natl Marine Fisheries Serv, Beaufort, NC USA. US Geol Survey, Ctr Coastal Geol, St Petersburg, FL USA. Univ N Carolina, Inst Marine Sci, Morehead City, NC 28557 USA. RP Woodruff, DL (reprint author), Battelle Marine Sci Lab, 1529 W Sequim Bay Rd, Sequim, WA 98382 USA. EM dana.woodruff@pnl.gov NR 49 TC 49 Z9 52 U1 2 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR PY 1999 VL 68 IS 1 BP 41 EP 52 DI 10.1016/S0034-4257(98)00108-4 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 178KG UT WOS:000079264400004 ER PT J AU Wang, LS Ding, CF Wang, XB Barlow, SE AF Wang, LS Ding, CF Wang, XB Barlow, SE TI Photodetachment photoelectron spectroscopy of multiply charged anions using electrospray ionization SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID FLIGHT MASS-SPECTROMETER; LYING ELECTRONIC STATES; GAS-PHASE; NEGATIVE-IONS; CONSTRUCTION PRINCIPLE; CLUSTER ANIONS; CARBON; HYDRATION; CHEMISTRY; ENERGIES AB A magnetic-bottle time-of-flight (TOF) photoelectron spectrometer, coupled with an electrospray ionization source, has been developed for the investigation of multiply charged anions in the gas phase. Anions formed in the electrospray source are guided by a radio-frequency quadrupole ion guide into a quadrupole ion trap, where the ions are accumulated. A unique feature of this apparatus involves the coupling of a TOF mass spectrometer to the ion trap with perpendicular ion extraction. The ion trap significantly improves the duty cycle of the experiments and allows photodetachment experiments to be performed with low repetition-rate lasers (10-20 Hz). This novel combination makes the photodetachment photoelectron spectroscopy studies of multiply charged anions possible for the first time. Furthermore, the perpendicular extraction of ions, pulsed out of the ion trap, to the TOF mass spectrometer allows the ion energies to be conveniently referenced to ground, simplifying the configuration of the TOF mass spectrometer and the subsequent magnetic-bottle TOF photoelectron spectrometer. The mass resolution ( M/Delta M) achieved is about 800 for smaller ions. The magnetic-bottle photoelectron spectrometer resolution is about 11 meV full width at half maximum for 0.5 eV photoelectrons with an overall resolution of Delta E/E similar to 2%. The detailed design, construction, and operation of the new apparatus are presented. (C) 1999 American Institute of Physics. [S0034-6748(99)00804-7]. 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 71 TC 171 Z9 171 U1 8 U2 33 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 APR PY 1999 VL 70 IS 4 BP 1957 EP 1966 DI 10.1063/1.1149694 PG 10 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500007 ER PT J AU Baker, KL Porter, JL Ruggles, LE Fehl, DL Chandler, GA Vargas, M Mix, LP Simpson, WW Deeney, C Chrien, RE Idzorek, GC AF Baker, KL Porter, JL Ruggles, LE Fehl, DL Chandler, GA Vargas, M Mix, LP Simpson, WW Deeney, C Chrien, RE Idzorek, GC TI Obtaining absolute spatial flux measurements with a time-resolved pinhole camera SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PLASMAS; DRIVE AB A technique is described to determine the spatial x-ray flux emitted from a hohlraum wall and subsequently transmitted through a diagnostic hole. This technique uses x-ray diodes, bolometers, and a time-resolved pinhole camera to determine the spatial flux of x rays emitted through a hohlraum's diagnostic hole. The primary motivation for this analysis was the relatively long duration, nearly 100 ns, of the x-ray drive present in z-pinch driven hohlraums. This radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and results in a partial obscuration that reduces the effective area over which diagnostics view the radiation. The effective change in area leads to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. An analysis similar to the one described below is then necessary to understand the radiation environment present in x-ray driven hohlraums when these diagnostics are used and hole closure is important. (C) 1999 American Institute of Physics. [S0034-6748(99)00204-X]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Baker, KL (reprint author), Univ Calif Davis, Livermore, CA 94551 USA. NR 18 TC 9 Z9 9 U1 3 U2 4 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 APR PY 1999 VL 70 IS 4 BP 2012 EP 2015 DI 10.1063/1.1149703 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500016 ER PT J AU Koelle, D Kleiner, R Ludwig, F Dantsker, E Clarke, J AF Koelle, D Kleiner, R Ludwig, F Dantsker, E Clarke, J TI High-transition-temperature superconducting quantum interference devices SO REVIEWS OF MODERN PHYSICS LA English DT Review ID HIGH-T-C; DC-SQUID MAGNETOMETERS; GRAIN-BOUNDARY JUNCTIONS; STEP-EDGE JUNCTIONS; LOW-FREQUENCY NOISE; MAGNETIC-FLUX NOISE; LOW 1/F NOISE; YBA2CU3O7 MULTILOOP MAGNETOMETERS; 30-DEGREES MISORIENTATION ANGLE; RESONANT-TUNNELING TRANSPORT AB The advent of high-T-c superconductors gave great impetus to the development of thin-film superconducting quantum interference devices (SQUIDs) for operation at temperatures up to the boiling point of liquid nitrogen, 77 K. The spectral density of the white flux noise can be calculated analytically for rf SQUIDs and by computer simulation for de SQUIDs; however, observed noise spectral densities are typically an order of magnitude higher. Low-frequency lif noise from thermally activated vortex motion is a much bigger issue in high-T-c SQUIDs at 77 K than in low-T-c SQUIDs because of the low flux-pinning energies in high-T-c superconductors. The magnitude of the noise depends strongly on the quality of the thin films, and much effort has been expended to improve techniques for depositing YBa2Cu3O7-x (YBCO) on lattice-matched single-crystal substrates. Substantial effort has also been invested in the development of new types of Josephson junctions, of which grain-boundary junctions are the most widely used in SQUIDs. Appropriate electronic read-out schemes largely eliminate lif noise from fluctuations in the junction critical current in both rf and dc SQUIDs. Typical levels of white flux noise are a few mu Phi(0) Hz(-1/2) (Phi(0) is the flux quantum). Magnetometers-consisting of a superconducting flux transformer coupled to a SQUID-achieve a white magnetic-field noise as low as 10 fT Hz(-1/)2, increasing to typically 30 fT Hz(-1/2) at 1 Hz. When these devices are operated in an unshielded environment, it is important to minimize the motion of trapped vortices and induced supercurrents, which can greatly increase the 1/f noise. The ambient noise is far greater than the intrinsic noise of the devices, but can be substantially reduced by various gradiometer configurations. There is now considerable effort to apply high-T-c SQUIDs in magnetocardiology, nondestructive evaluation, microscopy, and geophysics. [S0034-6861(99)00403-1]. C1 Univ Cologne, Lehrstuhl Angew Phys, Inst Phys 2, D-50937 Cologne, Germany. Univ Erlangen Nurnberg, Inst Phys 3, D-91058 Erlangen, Germany. Phys Tech Bundesanstalt, Sect Cryosensors, D-10587 Berlin, Germany. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Univ Cologne, Lehrstuhl Angew Phys, Inst Phys 2, D-50937 Cologne, Germany. RI Koelle, Dieter/E-5111-2011 NR 366 TC 257 Z9 261 U1 12 U2 94 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD APR PY 1999 VL 71 IS 3 BP 631 EP 686 DI 10.1103/RevModPhys.71.631 PG 56 WC Physics, Multidisciplinary SC Physics GA 191YU UT WOS:000080050500004 ER PT J AU Waters, RD Parker, FL AF Waters, RD Parker, FL TI Reliability analysis for hazardous waste treatment processes SO RISK ANALYSIS LA English DT Article DE reliability; Monte Carlo simulation; hazardous waste treatment; safety factor; packed tower; activated sludge ID PACKED-TOWER AERATION; HENRYS LAW CONSTANTS; ORGANIC-COMPOUNDS; TREATMENT PLANTS; DRINKING-WATER; VARIABILITY; CONTAMINANTS; UNCERTAINTY; FATE AB The reliability of a treatment process is addressed in terms of achieving a regulatory effluent concentration standard and the design safety factors associated with the treatment process. This methodology was then applied to two aqueous hazardous waste treatment processes: packed tower aeration and activated sludge (aerobic) biological treatment. The designs achieving 95 percent reliability were compared with those designs based on conventional practice to determine their patterns of conservatism. Scoping-level treatment costs were also related to reliability levels for these treatment processes. The results indicate that the reliability levels for the physical/chemical treatment process (packed tower aeration) based on the deterministic safety factors range from 80 percent to over 99 percent, whereas those for the biological treatment process range from near 0 percent to over 99 percent, depending on the compound evaluated. Increases in reliability per unit increase in treatment costs are most pronounced at lower reliability levels (less than about 80 percent) than at the higher reliability levels (greater than 90 percent, indicating a point of diminishing returns. Additional research focused on process parameters that presently contain large uncertainties may reduce those uncertainties, with attending increases in the reliability levels of the treatment processes. C1 Sandia Natl Labs, Carlsbad, NM 88220 USA. Vanderbilt Univ, Nashville, TN 37235 USA. RP Waters, RD (reprint author), Sandia Natl Labs, 115 N Main St, Carlsbad, NM 88220 USA. NR 43 TC 1 Z9 1 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 APR PY 1999 VL 19 IS 2 BP 249 EP 259 PG 11 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 223NJ UT WOS:000081846900008 PM 10765403 ER PT J AU Nordahl, T Bocher, M VanBrocklin, H O'Neil, J Espinoza, S Kusubov, N Budinger, T AF Nordahl, T Bocher, M VanBrocklin, H O'Neil, J Espinoza, S Kusubov, N Budinger, T TI Preliminary evidence of caudate dopamine asymmetry in humans SO SCHIZOPHRENIA RESEARCH LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging NSH&UCD, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-9964 J9 SCHIZOPHR RES JI Schizophr. Res. PD APR PY 1999 VL 36 IS 1-3 SI SI BP 244 EP 244 PG 1 WC Psychiatry SC Psychiatry GA 174XH UT WOS:000079061400709 ER PT J AU Smith, DH Seshadri, KS AF Smith, DH Seshadri, KS TI Infrared spectra of Mg2Ca(SO4)(3), MgSO4, hexagonal CaSO4, and orthorhombic CaSO4 SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE infrared spectra; Mg2Ca(SO4)(3); MgSO4; hexagonal CaSO4; orthorhombic CaSO4 AB Fourier-transform infrared (IR) spectra have been obtained from 450 to 1400 cm(-1) for the sulfate ion in Mg2Ca(SO4)(3), MgSO4, and the hexagonal and orthorhombic crystalline forms of CaSO4. This appears to be the first report of IR spectra for Mg2Ca(SO4)(3) and hexagonal CaSO4. Except for the number of satellite peaks, the spectra of Mg2Ca(SO4)(3) and hexagonal CaSO4 closely resemble those of MgSO4 and orthorhombic CaSO4. All of these spectra can be interpreted on the basis of C-2v symmetry for the anion. The cause(s) of satellite peaks are uncertain; the satellites suggest that the sulfate may occupy more than one position or orientation, with major:minor occupancy ratios of about 3:2. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US DOE, Fed Energy Technol Ctr, Morgantown, WV 26507 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. EG&G Tech Serv W Virginia Inc, Morgantown, WV 26507 USA. RP Smith, DH (reprint author), US DOE, Fed Energy Technol Ctr, POB 880,3610 Collins Ferry Rd, Morgantown, WV 26507 USA. EM dsmith@fetc.doe.gov NR 18 TC 20 Z9 20 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD APR PY 1999 VL 55 IS 4 BP 795 EP 805 DI 10.1016/S1386-1425(98)00206-6 PG 11 WC Spectroscopy SC Spectroscopy GA 173XP UT WOS:000079005300005 ER PT J AU Smith, DH Seshadri, KS AF Smith, DH Seshadri, KS TI Infrared spectroscopic method for analysis of Mg2Ca(SO4)(3) in mixtures with MgSO4 and/or CaSO4 SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE analytical method; Mg2Ca(SO4)3; MgSO4; CaSO4 ID COMBUSTION; WATER; PLANT AB Mg2Ca(SO4)(3) is prepared from, and may be found in, mixtures with MgSO4 and CaSO4. Such mixtures frequently occur in the ash produced by Various types of coal combustion, especially in filter cakes from pressurized fluidized bed combustion with dolomite as a SOx sorbent. Previously, qualitative analyses could be performed for Mg2Ca(SO4)(3) in these mixtures, but no quantitative analytical method was available. An infrared spectroscopic method has been developed that provides reasonably quantitative results for Mg2Ca(SO4)(3), MgSO4, and CaSO4 in their mixtures. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US DOE, Fed Energy Technol Ctr, Morgantown, WV 26507 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. EG&G Washington ESC, Morgantown, WV 26507 USA. RP Smith, DH (reprint author), US DOE, Fed Energy Technol Ctr, 3610 Collins Ferry Rd,POB 880, Morgantown, WV 26507 USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD APR PY 1999 VL 55 IS 4 BP 807 EP 816 DI 10.1016/S1386-1425(98)00224-8 PG 10 WC Spectroscopy SC Spectroscopy GA 173XP UT WOS:000079005300006 ER PT J AU Lin, Y Eldridge, JE Williams, JM Kini, AM Wang, HH AF Lin, Y Eldridge, JE Williams, JM Kini, AM Wang, HH TI Low-temperature softening of some Raman modes in BEDT-TTF and d(8)-BEDT-TTF SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE BEDT-TTF; bis(ethylenedithio) tetrathiafulvalene; Raman spectrum; temperature dependence ID ORGANIC SUPERCONDUCTOR; ELECTRON; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; ASSIGNMENT; SPECTRA; CATION AB We report the temperature-dependent frequencies of the strong features in the Raman spectra of neutral BEDT-TTF and d(8)-BEDT-TTF. We note an unusual softening of the features due to the modes involving the C-H vibrations in the terminal ethylene groups, as well as one mode involving the central double-bonded carbon atoms. We relate these softenings to the increased bending of the neutral molecule at low temperatures. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ British Columbia, Dept Phys, Vancouver, BC V6T 1Z1, Canada. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Eldridge, JE (reprint author), Univ British Columbia, Dept Phys, 6224 Agr Rd, Vancouver, BC V6T 1Z1, Canada. RI Kini, Aravinda/F-4467-2012 NR 13 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD APR PY 1999 VL 55 IS 4 BP 839 EP 843 DI 10.1016/S1386-1425(98)00230-3 PG 5 WC Spectroscopy SC Spectroscopy GA 173XP UT WOS:000079005300010 ER PT J AU Friedman, JH Fisher, NI AF Friedman, JH Fisher, NI TI Bump hunting in high-dimensional data SO STATISTICS AND COMPUTING LA English DT Article DE Data Mining; noisy function optimization; classification; association; rule induction AB Many data analytic questions can be formulated as (noisy) optimization problems. They explicitly or implicitly involve finding simultaneous combinations of values for a set of ("input") variables that imply unusually large (or small) values of another designated ("output") variable. Specifically, one seeks a set of subregions of the input variable space within which the value of the output variable is considerably larger (or smaller) than its average value over the entire input domain. In addition it is usually desired that these regions be describable in an interpretable form involving simple statements ("rules") concerning the input values. This paper presents a procedure directed towards this goal based on the notion of "patient" rule induction. This patient strategy is contrasted with the greedy ones used by most rule induction methods, and semi-greedy ones used by some partitioning tree techniques such as CART. Applications involving scientific and commercial data bases are presented. C1 Stanford Univ, Dept Stat, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. CSIRO, N Ryde, NSW 2113, Australia. NR 21 TC 169 Z9 172 U1 2 U2 16 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0960-3174 J9 STAT COMPUT JI Stat. Comput. PD APR PY 1999 VL 9 IS 2 BP 123 EP 143 DI 10.1023/A:1008894516817 PG 21 WC Computer Science, Theory & Methods; Statistics & Probability SC Computer Science; Mathematics GA 208VB UT WOS:000081011600004 ER PT J AU Jiang, W Weber, WJ Thevuthasan, S McCready, DE AF Jiang, W Weber, WJ Thevuthasan, S McCready, DE TI Rutherford backscattering spectrometry channeling study of ion-irradiated 6H-SiC SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Surface Analysis 98 CY JUN 16-19, 1998 CL PACIFIC NW NATL LAB, RICHLAND, WASHINGTON SP Amer Vacuum Soc, Appl Surface Sci Div, Pacific NW Natl Lab, William R Wiley Environm Molec Sci Lab, Amer Vacuum Soc, Pacific NW Chapter HO PACIFIC NW NATL LAB DE RBS; ion channeling; ion radiation effects; defect annealing; SiC ID BEAM-INDUCED AMORPHIZATION; SIC SINGLE-CRYSTALS; AMORPHOUS TRANSITION; SILICON-CARBIDE; DAMAGE; ACCUMULATION AB Single-crystal 6H-SiC (alpha-SiC) wafers were irradiated with He+, C+ and Si+ ions to fluences ranging from 7.5 x 10(17) to 1 x 10(20) ions m(-2) at various temperatures (160-870 K). Damage accumulation and subsequent defect annealing (up to 1170 K) have been studied using in situ 2.0 MeV He+ Rutherford backscattering spectrometry combined with ion channeling (RBS/C) methods. The defect concentration at the damage peak is observed to increase sigmoidally with increasing ion fluence during irradiation at low temperatures. The isochronal recovery of irradiation damage induced at low temperatures is observed to follow an exponential dependence on temperature. The relative disorder accumulated under 550 keV C+ ion irradiation as a function of irradiation temperature exhibits a significant decrease between 300 K and 670 K. Irradiation with 550 keV Si+ at 180 K to a fluence of 6.0 x 10(19) Si+ m(-2) produces an amorphous layer extending from the surface to a depth of 0.6 mu m. The thickness of this amorphous layer decreases linearly with annealing temperature up to 870 K., At low ion fluences, the defects produced by He+ irradiation at 160 K are more difficult to anneal at 300 K than those produced by Si+ irradiation, which suggests that trapping of helium may inhibit recombination. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Jiang, W (reprint author), Pacific NW Natl Lab, MSIN K8-93, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; OI Weber, William/0000-0002-9017-7365; Jiang, Weilin/0000-0001-8302-8313 NR 20 TC 23 Z9 23 U1 2 U2 6 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 APR PY 1999 VL 27 IS 4 BP 179 EP 184 DI 10.1002/(SICI)1096-9918(199904)27:4<179::AID-SIA459>3.0.CO;2-1 PG 6 WC Chemistry, Physical SC Chemistry GA 191GJ UT WOS:000080014000003 ER PT J AU Thevuthasan, S Jiang, W McCready, DE Chambers, SA AF Thevuthasan, S Jiang, W McCready, DE Chambers, SA TI Rutherford backscattering and channeling studies of Mg and Fe diffusion at the interface of gamma-Fe2O3(001)/MgO(001) SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Surface Analysis 98 CY JUN 16-19, 1998 CL PACIFIC NW NATL LAB, RICHLAND, WA SP Amer Vacuum Soc, Appl Surface Sci Div, Pacific NW Natl Lab, William R Wiley Environm Molec Sci Lab, Amer Vacuum Soc, Pacific NW Chapter HO PACIFIC NW NATL LAB DE RBS; Rutherford backscattering; channeling; diffusion; Mg; Fe ID MOLECULAR-BEAM EPITAXY; THIN-FILMS; GROWTH; FE3O4; ALPHA-FE2O3; GAMMA-FE2O3; PURE AB We have investigated the crystalline quality of an epitaxially-grown gamma-Fe2O3(001) film on MgO(001) substrate along with Mg and Fe inter-diffusion using Rutherford backscattering spectrometry (RBS) and channeling experiments. The channeling effect in the film appears to be reduced compared to an ideal single crystal, with the minimum yield for Fe determined to be in the range 16-18%, Growth at a substrate temperature of 450 degrees C promotes limited Mg out-diffusion into the film. Subsequent appealing results in further Mg out-diffusion, which increases in extent with increasing temperature. A minimum of 4 at.% Mg was detected throughout the film at temperatures below the onset of Fe in-diffusion, which was found to be 800 degrees C. This impurity cation concentration is comparable to the native vacancy concentration in gamma-Fe2O3 (4.8 at.%), suggesting that Mg occupies cation vacancy sites, as already established by Auger electron diffraction measurements for this system. The Mg concentration in the film was 8 at.%, while the associated Fe concentration in the substrate was 3.4 at.% after annealing at 800 degrees C. Moreover, these cation impurities were uniformly distributed throughout the film and substrate, with the fraction of substitution in both cases >90% at lower temperatures. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Thevuthasan, S (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. EM thev@pnl.gov NR 20 TC 5 Z9 5 U1 2 U2 2 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0142-2421 EI 1096-9918 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD APR PY 1999 VL 27 IS 4 BP 194 EP 198 DI 10.1002/(SICI)1096-9918(199904)27:4<194::AID-SIA468>3.0.CO;2-G PG 5 WC Chemistry, Physical SC Chemistry GA 191GJ UT WOS:000080014000005 ER PT J AU Bruch, R Merabet, H Bailey, M Showers, S Schneider, D AF Bruch, R Merabet, H Bailey, M Showers, S Schneider, D TI Development of X-ray and extreme ultraviolet (EUV) optical devices for diagnostics and instrumentation for various surface applications SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Surface Analysis 98 CY JUN 16-19, 1998 CL PACIFIC NW NATL LAB, RICHLAND, WA SP Amer Vacuum Soc, Appl Surface Sci Div, Pacific NW Natl Lab, William R Wiley Environm Molec Sci Lab, Amer Vacuum Soc, Pacific NW Chapter HO PACIFIC NW NATL LAB DE x-ray; ultraviolet; imaging; optical ID GLASS-CAPILLARY CONVERTERS; ELECTRON CAPTURE PROCESSES; HIGH-RESOLUTION; SYNCHROTRON-RADIATION; WAVELENGTH REGION; HIGH-SENSITIVITY; RANGE; COLLISIONS; EMISSION; SINGLE AB New methods of surface-sensitive instrumentation for the diagnostics of extreme ultraviolet (EUV), soft x-ray (SXR) and x-ray radiation have been developed. In particular, these methods of instrumentation are of great importance for studies of the interaction of electron, ion and photon beams with matter (atoms, molecules, ions, clusters, surfaces, micro- and submicron structures), Such collision studies are based on both glass capillary converters (GCCs) and multilayer mirrors (MLMs), gratings and crystals. The optical GCC device provides guiding, focusing and polarization analysis of short-wavelength radiation with a large bandwidth, and the MLM, grating and crystal optical elements are used for dispersing, focusing and polarization-sensitive studies of radiation within a more narrow bandwidth. In particular, we report here on the development of optical diagnostic devices, such as very compact EUV and SXR spectrometers, for measurements of polarization and spectral characteristics of short-wavelength radiation. Our high-throughput and high resolution compact spectrometers for the SXR range are based on grazing incidence spectrometers, MLMs and a sliced multi-layer grating (SMG) novel type of dispersion element. Furthermore, we will utilize a Schwarzschild objective with a spatial resolution of similar to 0.1-0.3 mu m for imaging surfaces following ion-surface interaction. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Nevada, Dept Phys, Reno, NV 89557 USA. Univ Nevada, Desert Res Inst, Ctr Atmospher Sci, Reno, NV 89506 USA. Lawrence Livermore Natl Lab, EBIT Facil, Livermore, CA 94550 USA. RP Bruch, R (reprint author), Univ Nevada, Dept Phys, Reno, NV 89557 USA. NR 50 TC 8 Z9 8 U1 1 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD APR PY 1999 VL 27 IS 4 BP 236 EP 246 DI 10.1002/(SICI)1096-9918(199904)27:4<236::AID-SIA549>3.0.CO;2-9 PG 11 WC Chemistry, Physical SC Chemistry GA 191GJ UT WOS:000080014000011 ER PT J AU Tonner, BP Droubay, T Denlinger, J Meyer-Ilse, W Warwick, T Rothe, J Kneedler, E Pecher, K Nealson, K Grundl, T AF Tonner, BP Droubay, T Denlinger, J Meyer-Ilse, W Warwick, T Rothe, J Kneedler, E Pecher, K Nealson, K Grundl, T TI Soft X-ray spectroscopy and imaging of interfacial chemistry in environmental specimens SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Surface Analysis 98 CY JUN 16-19, 1998 CL PACIFIC NW NATL LAB, RICHLAND, WASHINGTON SP Amer Vacuum Soc, Appl Surface Sci Div, Pacific NW Natl Lab, William R Wiley Environm Molec Sci Lab, Amer Vacuum Soc, Pacific NW Chapter HO PACIFIC NW NATL LAB DE XPS; XAFS; soft x-ray spectroscopy; Mn; Fe ID OXIDATION-STATE; TRANSITION-METALS; ABSORPTION; IRON; DICHROISM; MANGANESE AB Interfaces between minerals and water, and minerals and microbes, are chemically complex and traditionally have been considered beyond the capabilities of surface science techniques, except for model systems under controlled laboratory conditions. We report on some advances in soft x-ray spectroscopy and imaging that make it possible to extract meaningful chemical information about interfaces of specimens that have complex histories, involving environmental exposure, These measurements utilize x-ray absorption spectroscopy, in combination with spatial resolution, in a technique called x-ray spectromicroscopy. Examples are drawn from attempts at Mn and Fe speciation of biologically produced minerals, bio-corrosion deposits and clays. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. Univ Wisconsin, Dept Phys, Milwaukee, WI 53201 USA. Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Wisconsin, WATER Inst, Milwaukee, WI 53204 USA. RP Tonner, BP (reprint author), Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. RI Droubay, Tim/D-5395-2016 OI Droubay, Tim/0000-0002-8821-0322 NR 18 TC 16 Z9 16 U1 0 U2 4 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 APR PY 1999 VL 27 IS 4 BP 247 EP 258 DI 10.1002/(SICI)1096-9918(199904)27:4<247::AID-SIA553>3.0.CO;2-M PG 14 WC Chemistry, Physical SC Chemistry GA 191GJ UT WOS:000080014000012 ER PT J AU Dumas, P Weldon, MK Chabal, YJ Williams, GP AF Dumas, P Weldon, MK Chabal, YJ Williams, GP TI Molecules at surfaces and interfaces studied using vibrational spectroscopies and related techniques SO SURFACE REVIEW AND LETTERS LA English DT Review ID SUM-FREQUENCY GENERATION; INFRARED-ABSORPTION SPECTROSCOPY; ADSORBATE-INDUCED CHANGES; POTENTIAL-ENERGY SURFACE; HELIUM ATOM SCATTERING; ASYMMETRIC LINE-SHAPES; SINGLE-CRYSTAL SURFACE; DIELS-ALDER REACTIONS; HOLE PAIR MECHANISM; BURIED METAL LAYER AB Recent developments in the major experimental vibrational-spectroscopic techniques (i.e. infrared absorption, Raman scattering, high resolution electron loss, helium atom scattering and sum frequency generation) are reviewed and illustrated with selected results. Particular emphasis is given to two important topics which have attracted much attention in recent years: (i) the complex surface reactions taking place on technologically relevant surfaces and interfaces, and (ii) vibrational dynamics with emphasis on energy dissipation at surfaces. C1 Univ Paris Sud, Ctr Univ Paris Sud, LURE, F-91405 Orsay, France. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Brookhaven Natl Labs, Natl Synchrotron Light Source, Upton, NY 11970 USA. RP Dumas, P (reprint author), Univ Paris Sud, Ctr Univ Paris Sud, LURE, F-91405 Orsay, France. RI Chabal, Yves/A-5998-2011; NGUYEN LE, THANG LONG/C-9138-2011 OI Chabal, Yves/0000-0002-6435-0347; NR 147 TC 35 Z9 35 U1 3 U2 18 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD APR PY 1999 VL 6 IS 2 BP 225 EP 255 DI 10.1142/S0218625X99000263 PG 31 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 215LM UT WOS:000081383200008 ER PT J AU Kendelewicz, T Liu, P Doyle, CS Brown, GE Nelson, EJ Chambers, SA AF Kendelewicz, T Liu, P Doyle, CS Brown, GE Nelson, EJ Chambers, SA TI X-ray absorption and photoemission study of the adsorption of aqueous Cr(VI) on single crystal hematite and magnetite surfaces SO SURFACE SCIENCE LA English DT Article DE chromium; iron oxide; NEXAFS; solid liquid interfaces; surface chemical reaction; synchrotron radiation photoelectron spectroscopy; X-ray absorption spectroscopy ID SCANNING-TUNNELING-MICROSCOPY; TRANSITION-METAL OXIDES; CHROMATE REDUCTION; OXALATE ADSORPTION; CR(III) OXIDATION; WATER INTERFACE; FINE-STRUCTURE; IRON-OXIDES; SPECTROSCOPY; SORPTION AB The speciation of chromium in overlayers on atomically clean surfaces of single crystal magnetite (Fe3O4) and hematite (alpha-Fe2O3) were studied using Cr L-edge, Fe L-edge, and O K-edge X-ray absorption spectra collected with synchrotron radiation. The overlayers were produced by reaction of the surfaces with 5 mM or 50 mu M Na2CrO4 aqueous solutions in a N-2-filled glove bag in opaque containers at exposure times ranging from 1 min to over 60 min. X-ray absorption data were acquired using total electron yield and more surface-sensitive Auger yield detection. O 1s, Cr 2p, and Fe 2p photoemission spectra taken on the same samples corroborate findings from the Cr and Fe L-edge and O K-edge spectroscopy, and show that the outermost portion of the overlayers contains mostly Cr with little if any Fe, and are similar to 15 Angstrom thick for the high concentration exposures. The thickness of the overlayer increases with Cr(VI) solution concentration and exposure time up to this maximum thickness. The presence of chemically shifted components in the O Is photoemission spectra indicates OH- ligands around Cr and Fe. Comparison of the Cr L-edge X-ray absorption spectra of crystalline PbCrO4, which contains tetrahedrally coordinated Cr(VI), and crystalline FeCr2O4, which contains octahedrally coordinated Cr(III), with Cr L-edge spectra of the aqueous Cr(VI)-exposed iron oxide surfaces shows that Cr(VI) is reduced to Cr(III) on magnetite (111). For magnetite(111) surfaces reacted with 5 mM solutions for 10 min or longer, a significant amount of Cr(VI) is present in the outermost portion of the overlayer, indicating that Cr(VI) reduction is incomplete. Complete reduction of Cr(VI) was found on magnetite (111) exposed to the 50 mu M Na2CrO4 solution for 1 min or longer, indicating rapid reaction kinetics. We find that while Cr adsorbed on the (1 (1) over bar 02) surface of hematite (Fe2O3) remains in the original Cr(VI) form, small amounts are reduced to Cr(III) on (0001) hematite surfaces. This difference is due to the presence of Fe(II) on the (0001) hematite surfaces produced during annealing in a vacuum environment. These results corroborate earlier studies which have demonstrated that oxides containing Fe(II) in the near-surface region can reduce Cr(VI) to Cr(III), and they show that the overlayer consists of a mixture of FeOOH- and CrOOH-like phases, with the latter concentrated in the outermost 7-15 Angstrom and the former concentrated in the innermost portion of the passivating overlayer. At a thickness of >15 Angstrom, the passivating overlayer causes a reduction in the kinetics of the Cr(VI) + 3Fe(II) = Cr(III) + 3Fe(III) redox reaction. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Brown, GE (reprint author), Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. NR 54 TC 57 Z9 57 U1 4 U2 40 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 1 PY 1999 VL 424 IS 2-3 BP 219 EP 231 DI 10.1016/S0039-6028(98)00940-6 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 186DP UT WOS:000079712000015 ER PT J AU Sousa, L Robinson, V Fisher, J AF Sousa, L Robinson, V Fisher, J TI Forest products industry partners with government on R & D projects SO TAPPI JOURNAL LA English DT Article C1 US DOE, Off Ind Technol, Washington, DC 20545 USA. BCS Inc, Columbia, MD USA. RP Sousa, L (reprint author), US DOE, Off Ind Technol, Washington, DC 20545 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU TECH ASSN PULP PAPER IND INC PI NORCROSS PA 15 TECHNOLOGY PARK SOUTH, NORCROSS, GA 30092 USA SN 0734-1415 J9 TAPPI J JI TAPPI J. PD APR PY 1999 VL 82 IS 4 BP 88 EP 96 PG 9 WC Materials Science, Paper & Wood SC Materials Science GA 184MQ UT WOS:000079616300036 ER PT J AU Schlamadinger, B Marland, G AF Schlamadinger, B Marland, G TI Net effect of forest harvest on CO(2) emissions to the atmosphere: a sensitivity analysis on the influence of time SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID CARBON STORAGE; MANAGED FORESTS; STRATEGIES; TREES AB Forests can be harvested and regrown on a sustainable basis while harvested material is used to either store carbon in long-lived wood products or to displace carbon dioxide emissions from fossil fuel combustion. To frame the question whether this implies that harvesting forests is an effective strategy for mitigating the increase of carbon dioxide in the atmosphere, we use a carbon accounting model to ask how long it takes to return to the original carbon balance after a forest stand is clear-cut harvested for biofuels and other forest products. Although the numerical solution depends on a great variety of site-specific model input parameters, it is clear that the system will not return to its original carbon balance for a very long time (perhaps centuries) unless forest products are produced and used efficiently. Especially when the cycle of producing forest products involves initial harvest of a forest stand with a large standing stock of biomass, there is likely to be a long-standing debit in terms of net carbon emissions to the atmosphere. On the other hand, if forest harvest is produced and used with high efficiency and the rate of regrowth is high, potential carbon benefits can be very high over time and it is possible that there is never a carbon debit with respect to forest protection, even immediately following harvest. Any intent to use forest harvesting to help mitigate the buildup of carbon dioxide in the earth's atmosphere should be able to demonstrate that the forest regrowth and product use can compensate for the loss of carbon from the forest as a result of the initial harvest. C1 Joanneum Res Inst Energy Res, A-8010 Graz, Austria. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Schlamadinger, B (reprint author), Joanneum Res Inst Energy Res, Elisabethstr 5, A-8010 Graz, Austria. EM bernhard.schlamadinger@joanneum.ac.at NR 14 TC 16 Z9 16 U1 0 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 1999 VL 51 IS 2 BP 314 EP 325 DI 10.1034/j.1600-0889.1999.00014.x PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400014 ER PT J AU Tans, PP Wallace, DWR AF Tans, PP Wallace, DWR TI Carbon cycle research after Kyoto SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID ATMOSPHERIC CO2; ATLANTIC-OCEAN; THERMOHALINE CIRCULATION; 3-DIMENSIONAL SYNTHESIS; ANTHROPOGENIC CO2; DIOXIDE; TRANSPORT; FOREST; MODEL; FLUXES AB Recent progress in research of the global carbon cycle is reviewed and research needs for the immediate future are discussed, in light of the challenge posed to society to come to grips with the problem of man-made climate change. The carbon cycle in the oceans and on the land is reviewed, and how the atmosphere functions to couple them together. Major uncertainties still exist for any projection of the future atmospheric burden of carbon dioxide resulting from postulated emission scenarios of CO2. We present some ideas on how future policies designed to limit emissions or to sequester carbon can possibly be supported by scientific evidence of their effectiveness. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80304 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Tans, PP (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Mailcode R-E-CG1,325 Broadway, Boulder, CO 80304 USA. NR 49 TC 12 Z9 18 U1 1 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 1999 VL 51 IS 2 BP 562 EP 571 DI 10.1034/j.1600-0889.1999.00031.x PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400031 ER PT J AU Jankowski, AF AF Jankowski, AF TI Nanohardness and chemical bonding of boron nitride films SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 14th International Vacuum Congress/10th International Conference on Solid Surfaces/5th International Conference on Nanometre-Scale Science and Technology/10th International Conference on Quantitative Surface Analysis CY AUG 31-SEP 04, 1998 CL BIRMINGHAM, ENGLAND SP British Vacuum Council, Inst Phys, Int Union Vacuum Sci Tech & Applicat DE boron nitride; chemical bonding; hardness; reactive sputtering; X-ray absorption ID ABSORPTION FINE-STRUCTURE; PULSED-LASER DEPOSITION; THIN-FILMS; SPUTTER-DEPOSITION; ELASTIC-MODULUS; C-BN; GROWTH; HARDNESS; INDENTATION; STRESS AB Boron-nitride (BN) films are deposited by the reactive sputter deposition from fully dense, boron targets utilizing a planar magnetron source and an argon-nitrogen working gas mixture. Near-edge X-ray absorption fine structure analysis reveals distinguishing features of chemical bonding within the boron 1s photoabsorption cross-section. The hardness of the BN film surface is measured using nanoindentation. The sputter deposition conditions as well as the post-deposition treatments of annealing and nitrogen-ion implantation effect the chemical bonding and the film hardness. The hardness of a layered B/BN coating is decreased twofold after an anneal whereas the hardness of a BN film is increased four-fold by a 90 keV N(+) implant. A model is proposed to quantify the film hardness that ranges from 0.1 to 30 GPa using the relative peak intensities of the pi*-resonances to the boron 1s spectra. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Jankowski, AF (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM jankowski1@llnl.gov NR 31 TC 3 Z9 4 U1 0 U2 0 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 APR PY 1999 VL 343 SI SI BP 238 EP 241 DI 10.1016/S0040-6090(98)01634-4 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 210KC UT WOS:000081103100063 ER PT J AU Miller, CS Gammage, RB Jankovic, JT AF Miller, CS Gammage, RB Jankovic, JT TI Exacerbation of chemical sensitivity: a case study SO TOXICOLOGY AND INDUSTRIAL HEALTH LA English DT Article DE environmental illness; indoor air; multiple chemical sensitivity; questionnaire; volatile organic compound AB We report exacerbation of symptoms and chemical intolerances in three of four self-described chemically sensitive women following relocation to a newly constructed office building. Levels of total volatile organic compounds (TVOCs) in this building prior to occupancy were approximately 200 mu g/m(3) (toluene equivalent units) with a myriad of individual components present. By day 50 alter occupancy, the concentration of TVOCs in the building dropped to approximately 50 mu g/m(3). Nevertheless. three women reported significant worsening of their symptoms with spreading of their sensitivities to previously tolerated chemical exposures. One woman relocated to another building, while the other two managed their symptoms by reducing time spent in the building or by using a room air cleaner. By day 600 following occupancy, although TVOCs had increased significantly (perhaps due to cleaning agents), there were fewer individual VOCs present in the air, and some of the women were able to tolerate the air in the building. We conclude that complex mixtures of VOCs at very low levels tolerated by the majority of building occupants may pose problems for persons who report pre-existing chemical sensitivities. TVOC measurements may not correlate with symptoms in these individuals. Reasonable accommodations by an employer can reduce problem exposures, making it possible for some affected individuals to continue productive employment. C1 Univ Texas, Hlth Sci Ctr, Dept Family Practice, San Antonio, TX 78284 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Safety & Hlth Protect Div, Oak Ridge, TN 37831 USA. RP Miller, CS (reprint author), Univ Texas, Hlth Sci Ctr, Dept Family Practice, Suite 610-L,7703 Floyd Curl Dr, San Antonio, TX 78284 USA. NR 3 TC 4 Z9 4 U1 1 U2 2 PU STOCKTON PRESS PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 0748-2337 J9 TOXICOL IND HEALTH JI Toxicol. Ind. Health PD APR-JUN PY 1999 VL 15 IS 3-4 BP 398 EP 402 PG 5 WC Public, Environmental & Occupational Health; Toxicology SC Public, Environmental & Occupational Health; Toxicology GA 295BK UT WOS:000085945900013 PM 10416291 ER PT J AU Sun, Y Petersen, JN Bear, J Clement, TP Hooker, BS AF Sun, Y Petersen, JN Bear, J Clement, TP Hooker, BS TI Modeling microbial transport and biodegradation in a dual-porosity system SO TRANSPORT IN POROUS MEDIA LA English DT Article DE modeling; biodegradation; microbial transport; dual-porosity; kinetics ID POROUS-MEDIA; CONTAMINANT TRANSPORT; REACTIVE TRANSPORT; WATER; NUTRIENT; TERM AB A mathematical model describing microbial transport and growth in a heterogeneous aquifer domain, composed of overlapping subdomains of high-permeability and low-permeability materials, is developed. Each material is conceptually visualized as a continuum which occupies the entire considered spatial aquifer domain. Based on the assumption that advection in the low-permeability domain is negligible, the mathematical model is solved by using a publically available reactive transport code. The importance of modeling microbial transport and growth in such a dual-porosity system is demonstrated through a hypothetical case study. C1 Washington State Univ, Ctr Multiphase Environm Res, Pullman, WA 99164 USA. Technion Israel Inst Technol, Dept Civil Engn, IL-32000 Haifa, Israel. Pacific NW Natl Lab, Bioproc Grp, Richland, WA 99352 USA. RP Petersen, JN (reprint author), Washington State Univ, Ctr Multiphase Environm Res, Pullman, WA 99164 USA. RI Petersen, James/B-8924-2008; Sun, Yunwei/C-9751-2010 NR 24 TC 3 Z9 3 U1 1 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-3913 J9 TRANSPORT POROUS MED JI Transp. Porous Media PD APR PY 1999 VL 35 IS 1 BP 49 EP 65 DI 10.1023/A:1006551627151 PG 17 WC Engineering, Chemical SC Engineering GA 197GN UT WOS:000080357200004 ER PT J AU Su, GW Geller, JT Pruess, K Wen, F AF Su, GW Geller, JT Pruess, K Wen, F TI Experimental studies of water seepage and intermittent flow in unsaturated, rough-walled fractures SO WATER RESOURCES RESEARCH LA English DT Article ID WETTING FRONT INSTABILITY; POROUS-MEDIA; RELATIVE PERMEABILITY; ROCK FRACTURES; GRAVITY; DISPLACEMENT; INFILTRATION; SATURATION; MECHANISMS; MOVEMENT AB Flow visualization experiments were conducted on a transparent replica of a natural, rough-walled rock fracture from the Stripa Mine, Sweden, for inlet conditions of constant pressure and flow rate over a range of angles of inclination. The experiments demonstrated that infiltrating water proceeds through unsaturated rock fractures along nonuniform, localized preferential flow paths. Even though constant inlet conditions were maintained, pervasive unsteady or intermittent flow was also observed in these experiments, where portions of the flow channel underwent cycles of snapping and reforming. Experiments conducted on parallel plates with a sequence of apertures progressing from small to large to small reproduced intermittent flow. Measurements of the frequency of intermittent flow events and the volume of water metered between events were obtained from the fracture replica and parallel plate experiments and related to the Bond and capillary numbers to generalize the results. The frequency data from the fracture replica experiments did not follow the same trend as the data from the parallel plate experiments for similar Bond and capillary numbers, but the volume of water metered data was consistent in these experiments. C1 Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RP Su, GW (reprint author), Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. EM grace_su@lbl.gov; jtgeller@lbl.gov; k_pruess@lbl.gov; fxwen@bechtel.com NR 44 TC 93 Z9 93 U1 1 U2 15 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 APR PY 1999 VL 35 IS 4 BP 1019 EP 1037 DI 10.1029/1998WR900127 PG 19 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 181FH UT WOS:000079430100009 ER PT J AU Pruess, K AF Pruess, K TI A mechanistic model for water seepage through thick unsaturated zones in fractured rocks of low matrix permeability SO WATER RESOURCES RESEARCH LA English DT Article ID SANDY VADOSE ZONE; PREFERENTIAL FLOW; CAPILLARY BARRIERS; POROUS-MEDIUM; INFILTRATION; FIELD; FLUID; MASS AB The theme developed in this paper is that water seepage in thick unsaturated zones in fractured rocks of low matrix permeability cannot be understood by considering spatial and temporal averages. We suggest that most such seepage proceeds in an unsteady, episodic manner in localized preferential pathways. Mechanisms are proposed and explored which permit water to flow relatively freely in networks of interconnected fractures in the presence of strong suction pressures from an unsaturated rock matrix. Imbibition into the rock matrix is reduced by limited wetted area, the episodic nature of flow, and possibly also by the presence of mineral coatings of low permeability on the fracture walls. These effects and conditions combine to limit total imbibition rates to values less than saturated matrix hydraulic conductivity, leaving the rock matrix in partially saturated conditions even as water is flowing freely in portions of the fracture network. The proposed conceptual model is elaborated and substantiated with analytical estimates and numerical simulation studies. Mechanisms are demonstrated that can funnel distributed seepage into spatially localized preferential paths. Subsequent horizontal broadening from dispersive mechanisms is found to be a slow process for fractures of high intrinsic permeability. The presence of an unsaturated rock matrix provides constraints on fracture-matrix interface areas for imbibition and on the frequency of episodic deep seepage events. Further studies are needed to test the proposed model. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Pruess, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 50 TC 69 Z9 72 U1 2 U2 12 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 APR PY 1999 VL 35 IS 4 BP 1039 EP 1051 DI 10.1029/1998WR900100 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 181FH UT WOS:000079430100010 ER PT J AU Zhang, DX AF Zhang, DX TI Nonstationary stochastic analysis of transient unsaturated flow in randomly heterogeneous media SO WATER RESOURCES RESEARCH LA English DT Article ID ANISOTROPIC POROUS FORMATIONS; SOIL HYDRAULIC-PROPERTIES; VARIABLY SATURATED SOILS; STEADY-STATE FLOW; SOLUTE TRANSPORT; VELOCITY COVARIANCE; NUMERICAL-MODELS; GROUNDWATER-FLOW; MONTE-CARLO; FIELD-SCALE AB In this study, a first-order, nonstationary stochastic model of transient flow is developed which is applicable to the entire domain of a bounded vadose zone in the presence of sink/source. We derive general equations governing the statistical moments of the flow quantities by perturbation expansions. Owing to the mathematical complexity of the equations, in general we need to solve them numerically. The numerical moment equation approach, however, has the flexibility in handling different boundary conditions, flow configurations, input covariance structures, and soil constitutive relationships. The moment equations presented in this study are simpler and easier to solve than those in the literature for transient unsaturated how. We solve these moment equations by the method of finite differences and demonstrate the developed model through some one- and two-dimensional examples under various transient conditions. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp EES5, Los Alamos, NM 87545 USA. RP Zhang, DX (reprint author), Univ Calif Los Alamos Natl Lab, Geoanal Grp EES5, MS C306, Los Alamos, NM 87545 USA. RI Zhang, Dongxiao/D-5289-2009 OI Zhang, Dongxiao/0000-0001-6930-5994 NR 47 TC 52 Z9 58 U1 0 U2 1 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 APR PY 1999 VL 35 IS 4 BP 1127 EP 1141 DI 10.1029/1998WR900126 PG 15 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 181FH UT WOS:000079430100017 ER PT J AU Soukoulis, CM Economou, EN AF Soukoulis, CM Economou, EN TI Electronic localization in disordered systems SO WAVES IN RANDOM MEDIA LA English DT Article ID HIGHLY ANISOTROPIC SYSTEMS; OPTICAL-ABSORPTION EDGE; OFF-DIAGONAL DISORDER; QUANTUM PERCOLATION; SCALING THEORY; 2 DIMENSIONS; ANDERSON LOCALIZATION; 3-DIMENSIONAL SYSTEMS; FRACTAL CHARACTER; LANDAUER FORMULA AB A brief review is given of the current understanding of the electronic structure, transport properties and the nature of the electronic states in disordered systems. A simple explanation for the observed exponential behaviour in the density of states (Urbach tails) based on short-range Gaussian fluctuations is presented. The theory of Anderson localization in a disordered system is reviewed. Basic concepts, and the physics underlying the effects of weak localization, are discussed. The scaling as well as the self-consistent theory of localization are briefly reviewed. It is then argued that the problem of localization in a random potential within the so-called ladder approximation is formally equivalent to the problem of finding a bound state in a shallow potential well. Therefore all states are exponentially localized in d = 1 and d = 2. The fractal nature of the states is also discussed. Scaling properties in highly anisotropic systems are also discussed. A brief presentation of the recently observed metal-to-insulator transition in d = 2 is given and, finally, a few remarks about interaction effects in disordered systems are presented. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Soukoulis, CM (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Economou, Eleftherios /E-6374-2010; Soukoulis, Costas/A-5295-2008 NR 57 TC 40 Z9 41 U1 1 U2 13 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0959-7174 J9 WAVE RANDOM MEDIA JI Waves Random Media PD APR PY 1999 VL 9 IS 2 BP 255 EP 269 DI 10.1088/0959-7174/9/2/310 PG 15 WC Physics, Multidisciplinary SC Physics GA 199EA UT WOS:000080466400011 ER PT J AU Adler, TA Dogan, ON AF Adler, TA Dogan, ON TI Erosive wear and impact damage of high-chromium white cast irons SO WEAR LA English DT Article; Proceedings Paper CT 12th International Conference on Wear of Materials CY APR 25-29, 1999 CL ATLANTA, GA DE erosive wear; high-chromium white cast irons; spherical and angular particles ID SOLID PARTICLE IMPINGEMENT; ABRASION RESISTANCE; DEFORMATION; METALS; INDENTATION; HARDNESS; ALUMINUM; ALLOYS; MODEL AB High-chromium white cast irons rue used extensively in environments where small particle impact causes considerable damage. In this study, three white cast irons with a variation in carbide volume fraction were eroded by spherical and angular particles. The white cast irons eroded at a higher rate when the erodent was WC-Co spheres than when the erodent was alumina particles. When eroded by spherical WC-Co particles, the eutectic white cast iron eroded at a higher rate than the hypoeutectic white cast iron. The results of the erosion experiments were interpreted in terms of a mechanism of platelet formation involving strain localization. The greater strain hardening rate of the hypoeutectic white cast iron can account for the better erosion resistance compared to the eutectic white cast iron, based on the strain localization mechanism. The larger size and greater density of the WC-Co spheres can account for the higher erosion rates of the white cast irons when eroded with WC-Co spheres compared to the erosion rate with alumina particles. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 US Dept Energy, Albany Res Ctr, Albany, OR 97321 USA. RP Adler, TA (reprint author), US Dept Energy, Albany Res Ctr, 1450 Queen Ave SW, Albany, OR 97321 USA. EM adler@alrc.doe.gov NR 28 TC 19 Z9 20 U1 2 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD APR PY 1999 VL 225 BP 174 EP 180 DI 10.1016/S0043-1648(99)00010-1 PN 1 PG 7 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 190EM UT WOS:000079949200022 ER EF