FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Considine, DB Douglass, AR Connell, PS Kinnison, DE Rotman, DA AF Considine, DB Douglass, AR Connell, PS Kinnison, DE Rotman, DA TI A polar stratospheric cloud parameterization for the global modeling initiative three-dimensional model and its response to stratospheric aircraft SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TOTAL REACTIVE NITROGEN; ANTARCTIC STRATOSPHERE; SHUTTLE MISSIONS; SULFURIC-ACID; OZONE HOLE; HNO3; ICE; PHOTOCHEMISTRY; VALIDATION; DEPLETION AB We describe a new parameterization of polar stratospheric clouds (PSCs) which was written for and incorporated into the three-dimensional (3-D) chemistry and transport model (CTM) developed for NASA's Atmospheric Effects of Aviation Project (AEAP) by the Global Modeling Initiative (GMI). The parameterization was designed to respond to changes in NOy and H2O produced by high-speed civilian transport (HSCT) emissions. The parameterization predicts surface area densities (SADs) of both Type 1 and Type 2 PSCs for use in heterogeneous chemistry calculations. Type 1 PSCs are assumed to have a supercooled ternary sulfate (STS) composition, and Type 2 PSCs are treated as water ice with a coexisting nitric acid trihydrate (NAT) phase. Sedimentation is treated by assuming that the PSC particles obey lognormal size distributions, resulting in a realistic mass flux of condensed phase H2O and HNO3, We examine a simulation of the Southern Hemisphere high-latitude lower stratosphere winter and spring seasons driven by temperature and wind fields from a modified version of the National Center for Atmospheric Research (NCAR) Middle Atmosphere Community Climate Model Version 2 (MACCM2). Predicted PSC SADs and median radii for both Type 1 and Type 2 PSCs are consistent with observations, Gas phase HNO3 and H2O concentrations in the high-latitude lower stratosphere qualitatively agree with Cryogenic Limb Array Etalon Spectrometer (CLAES) HNO3 and Microwave Limb Sounder (MLS) H2O observations. The residual denitrification and dehydration of the model polar vortex after polar winter compares well with atmospheric trace molecule spectroscopy (ATMOS) observations taken during November 1994. When the NO, and H2O emissions of a standard 500-aircraft HSCT fleet with a NOx emission index of 5 are added, NOx and H2O concentrations in the Southern Hemisphere polar vortex before winter increase by up to 3%. This results in earlier onset of PSC formation, denitrification, and dehydration. Active Cry increases and produces small (similar to 1%) decreases in lower stratospheric vortex O-3 concentrations during the spring relative to the HSCT-free run. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. EM dbc@atmos.umd.edu RI Douglass, Anne/D-4655-2012 NR 53 TC 42 Z9 42 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 16 PY 2000 VL 105 IS D3 BP 3955 EP 3973 DI 10.1029/1999JD900932 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 286ZP UT WOS:000085479000033 ER PT J AU Bakac, A AF Bakac, A TI Hydrogen atom abstraction by metal-oxo and metal-superoxo complexes: Kinetics and thermodynamics SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID AQUEOUS-SOLUTION; ACYL RADICALS; SUPEROXOCHROMIUM(III) ION; AQUACHROMIUM(IV) ION; ELECTRON-TRANSFER; PULSE-RADIOLYSIS; PROTON-TRANSFER; RATE CONSTANTS; ALDEHYDES; OXIDATION AB The superoxochromium complex CraqOO2+ abstracts a hydrogen atom from CMe3CHO in acidic aqueous solution with k = 0.16 M-1 s(-1). This rate constant is only similar to 10(2) times smaller than that for the reaction of CraqO2+ with the same aldehyde, k = 23 M-1 s(-1), in contrast to the much greater reactivity difference between alkoxyl and alkylperoxyl radicals, k(t-BuO)/k(t-BuOO) approximate to 10(6) The, absolute rate constants for hydrogen atom abstraction from a common reagent by metal-ore and -superoxo species and the corresponding organic oxygen-centered radicals, RO. and ROO., can now be compared for the first time: k(BuO) (9 x 10(7) M-1 s(-1)) > k(CrO)(23) greater than or equal to k(BuOO)(8) > k(CrOO) (0.16) The reactivity of individual species is explained by the energetics of the O-H bands in ROH, ROOH, CraqOH2+, and CraqOOH2+. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Bakac, A (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 52 TC 36 Z9 36 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 FEB 16 PY 2000 VL 122 IS 6 BP 1092 EP 1097 DI 10.1021/ja993371s PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 285HT UT WOS:000085384200012 ER PT J AU Thompson, LH West, MG AF Thompson, LH West, MG TI XRCC1 keeps DNA from getting stranded SO MUTATION RESEARCH-DNA REPAIR LA English DT Review DE XRCC1; DNA; single-strand breaks ID BASE-EXCISION-REPAIR; SISTER-CHROMATID EXCHANGE; HAMSTER CELL-LINE; MOLECULAR NICK-SENSOR; CROSS-LINKING AGENTS; LIGASE-III ACTIVITY; POLYMERASE-BETA; POLY(ADP-RIBOSE) POLYMERASE; BREAK REPAIR; MAMMALIAN-CELLS C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Thompson, LH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,POB 808, Livermore, CA 94551 USA. NR 149 TC 298 Z9 319 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8777 J9 MUTAT RES-DNA REPAIR JI Mutat. Res.-DNA Repair PD FEB 16 PY 2000 VL 459 IS 1 BP 1 EP 18 DI 10.1016/S0921-8777(99)00058-0 PG 18 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 286JF UT WOS:000085439400001 PM 10677679 ER PT J AU Pluth, JM Ramsey, MJ Tucker, JD AF Pluth, JM Ramsey, MJ Tucker, JD TI Role of maternal exposures and newborn genotypes on newborn chromosome aberration frequencies SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article DE newborns; chromosome aberrations; CYP 1A1; maternal smoking ID MICROSOMAL EPOXIDE HYDROLASE; GLUTATHIONE S-TRANSFERASES; HPRT MUTANT LYMPHOCYTES; LUNG-CANCER; GENETIC-POLYMORPHISM; CYTOGENETIC DAMAGE; SMOKING MOTHERS; DNA-ADDUCTS; CIGARETTE SMOKERS; TOBACCO-SMOKE AB Maternal exposures may induce chromosome damage and birth defects in the fetus. Polymorphic variation in genes coding for enzymes involved in metabolic activation and detoxification of environmental procarcinogens may account for some of the differences in chromosome aberration frequencies in newborns. In this study, 40 mothers completed questionnaires regarding exposures they received during their pregnancy. Umbilical cord blood samples were analyzed for chromosome aberrations. An average of 1020 metaphase cell equivalents (equal to 1020 G-banded cells) were examined from each newborn. In 26 of the newborns, genotyping analysis was performed for genes functioning in metabolic activation and detoxification (cytochrome P450 genes: CYP2D6 and CYP1A1, and phase II genes: NAT1, NAT2, GSTT1, GSTM1, GSTP1, and epoxide hydrolase). A significant association between the CYP1A1 MspI polymorphism and chromosome aberration frequencies was observed in the newborns (p = 0.02), with heterozygotes showing higher aberration frequencies than the wild type homozygotes. Some large differences in chromosome aberration frequencies for other genotypes were also noted, but these were not statistically significant. Exposure to tobacco smoke in utero also appeared to increase translocation frequencies. The mean frequency of translocations per 100 cell equivalents from newborns of mothers who smoked during pregnancy was significantly higher than that of newborns whose mothers did not smoke (0.21 vs. 0.11, respectively, p = 0.045). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Stanford Univ, Dept Radiat Oncol, Canc Biol Res Lab, Stanford, CA 94305 USA. RP Tucker, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. NR 46 TC 49 Z9 53 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5718 J9 MUTAT RES-GEN TOX EN JI Mutat. Res. Genet. Toxicol. Environ. Mutagen. PD FEB 16 PY 2000 VL 465 IS 1-2 BP 101 EP 111 DI 10.1016/S1383-5718(99)00217-X PG 11 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 291XT UT WOS:000085765600012 PM 10708975 ER PT J AU Ramirez-Vick, JE Garcia, AA Lee, J AF Ramirez-Vick, JE Garcia, AA Lee, J TI Immobilization of silver ions onto paramagnetic particles for binding and release of a biotin-labeled oligonucleotide SO REACTIVE & FUNCTIONAL POLYMERS LA English DT Article DE oligonucleotide; silver ions; DNA recovery; FAM; FITC; Texas Red; paramagnetic particles; DNA elution ID CHROMATOGRAPHY; RETENTION; BEHAVIOR AB Paramagnetic particles with amino functional groups can be derivatized using glutaraldehyde and thiourea in order to immobilize silver ions. The silver immobilization procedure did not alter the surface morphology of the particles according to Tapping mode AFM imaging. Rutherford backscattering showed that silver resides on the particle surface while iron is present throughout the particle. Particle-Induced X-Ray Emission spectroscopy determined that the derivatized particles have a silver capacity of 7 wt%. Paramagnetic particles containing immobilized silver ions have an affinity binding constant of the order 10(8) for mono- and tri-biotin-labeled oligonuceotide with primary sequence 3'-GCCCCTTTTTAAAAACCCCG-5' while the original amino particles have little affinity for the oligonucleotide. Measurement of binding and release was enabled by attaching either fluorescein isothioocyanate (FITC) to the 3'-end or Texas Red or fluorescein phosphoramidite (FAM) to the 5'-end of the oligonucleotide. Up to a 97% release of the FAM labeled biotinylated oligonucleotide from the particle surface can be achieved using an aqueous solution of thiodiglycol. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Mayo Clin Scottsdale, Scottsdale, AZ 85259 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Arizona State Univ, Dept Chem Bio & Mat Engn, Tempe, AZ 85287 USA. RP Lee, J (reprint author), Mayo Clin Scottsdale, 13400 E Shea Blvd, Scottsdale, AZ 85259 USA. OI Ramirez-Vick, Jaime/0000-0001-9845-3734 NR 11 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-5148 J9 REACT FUNCT POLYM JI React. Funct. Polym. PD FEB 16 PY 2000 VL 43 IS 1-2 BP 53 EP 62 DI 10.1016/S1381-5148(98)00095-9 PG 10 WC Chemistry, Applied; Engineering, Chemical; Polymer Science SC Chemistry; Engineering; Polymer Science GA 288FD UT WOS:000085550900007 ER PT J AU Arenkov, P Kukhtin, A Gemmell, A Voloshchuk, S Chupeeva, V Mirzabekov, A AF Arenkov, P Kukhtin, A Gemmell, A Voloshchuk, S Chupeeva, V Mirzabekov, A TI Protein microchips: Use for immunoassay and enzymatic reactions SO ANALYTICAL BIOCHEMISTRY LA English DT Article DE fluorescence detection; immunoassay; antigen; antibody; enzyme; microchips ID OLIGONUCLEOTIDE MICROCHIPS; HYBRIDIZATION; GELS; DNA AB Different proteins such as antibodies, antigens, and enzymes were immobilized within the 100 x 100 x 20-mu m gel pads of protein microchips. A modified polyacrylamide gel has been developed to accommodate proteins of a size up to 400,000 daltons, Electrophoresis in the microchip reaction chamber speeded up antigen-antibody interactions within the gel. Protein microchips were used in immunoassays for detection of antigens or antibodies, as well as to carry out enzymatic reactions and to measure their kinetics in the absence or presence of an inhibitor. A protein microchip can be used several times in different immunoassays and enzymatic kinetic measurements. (C) 2000 Academic Press. C1 Argonne Natl Lab, Biochip Technol Ctr, Argonne, IL 60439 USA. Russian Acad Sci, Engelhardt Inst Mol Biol, Joint Human Genome Program, Moscow 117984, Russia. RP Mirzabekov, A (reprint author), Argonne Natl Lab, Biochip Technol Ctr, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 412 Z9 438 U1 7 U2 40 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD FEB 15 PY 2000 VL 278 IS 2 BP 123 EP 131 DI 10.1006/abio.1999.4363 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 285GN UT WOS:000085381500005 PM 10660453 ER PT J AU O'Brien, JC Jones, VW Porter, MD Mosher, CL Henderson, E AF O'Brien, JC Jones, VW Porter, MD Mosher, CL Henderson, E TI Immunosensing platforms using spontaneously adsorbed antibody fragments on gold SO ANALYTICAL CHEMISTRY LA English DT Article ID THIN-LAYER SPECTROELECTROCHEMISTRY; SELF-ASSEMBLED MONOLAYERS; QUARTZ-CRYSTAL MICROBALANCE; ATOMIC-FORCE MICROSCOPY; SOLID-LIQUID INTERFACES; INFRARED SPECTROELECTROCHEMISTRY; PROTEIN ADSORPTION; TAPPING-MODE; SURFACES; LENGTH AB This paper describes the construction and characterization of miniaturized antigenic immunosurfaces composed of spontaneously adsorbed Fab'-SH fragments on gold. Rabbit Fab'-SH fragments contain a free sulfhydryl group that forms a thiolate bond with a gold substrate as detailed by X-ray photoelectron spectroscopy. This approach creates surfaces of higher epitope density, a factor critical to the early detection of disease, than surfaces composed of adsorbed whole molecule IgG on gold, The viability and specificity of antigenic Fab'-SH immunosurfaces is demonstrated using atomic force microscopy and confocal fluorescence microscopy, and possible explanations for the larger epitope density are discussed. C1 US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. NR 49 TC 65 Z9 65 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD FEB 15 PY 2000 VL 72 IS 4 BP 703 EP 710 DI 10.1021/ac990581e PG 8 WC Chemistry, Analytical SC Chemistry GA 285HE UT WOS:000085383000008 PM 10701253 ER PT J AU Fellers, RS Sasaki, J Colvin, M AF Fellers, RS Sasaki, J Colvin, M TI Metabolic oxidation of carcinogenic arylamines by P-450 monooxygenases: Theoretical support for the one-electron-transfer mechanism. SO BIOCHEMISTRY LA English DT Meeting Abstract C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Computat Biol Grp, Livermore, CA 94550 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 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 15 PY 2000 VL 39 IS 6 MA 47 BP 1552 EP 1552 PG 1 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 285NX UT WOS:000085396100090 ER PT J AU Michalczyk, R Orji, CC Silks, LA AF Michalczyk, R Orji, CC Silks, LA TI NMR studies of the dynamics of DNA oligonucleotides using heteronuclear labeling and relaxation measurements. SO BIOCHEMISTRY LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Paradigm Organ Inc, Raleigh, NC 27606 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 15 PY 2000 VL 39 IS 6 MA 132 BP 1571 EP 1572 PG 2 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 285NX UT WOS:000085396100173 ER PT J AU Reeder, RJ Nugent, M Lamble, GM Tait, CD Morris, DE AF Reeder, RJ Nugent, M Lamble, GM Tait, CD Morris, DE TI Uranyl incorporation into calcite and aragonite: XAFS and luminescence studies SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID LASER-INDUCED FLUORESCENCE; CARBONATE COMPLEXES; AQUEOUS-SOLUTION; URANIUM; SPECTROSCOPY; ION; COORDINATION; SPECIATION; CHEMISTRY; INTERFACE AB X-ray absorption, luminescence, and Raman spectroscopic studies of U(VI)-containing calcite and aragonite show that the UO22+ ion, the dominant and mobile form of dissolved uranium in near-surface waters, has a disordered and apparently less stable coordination environment when incorporated into calcite in comparison to aragonite, both common polymorphs of CaCO3. Our findings suggest that calcite, a widely distributed authigenic mineral in soils and near-surface sediments and a principal weathering product of concrete-based containment structures, is not likely to be a suitable host for the long-term sequestration of U(VI). The more stable coordination provided by aragonite suggests that its long-term retention should be favored in this phase, until it inverts to calcite. Consequently, future remobilization of U(VI) coprecipitated with calcium carbonate minerals should not be ruled out in assessments of contaminated sites. Our observation of a similar equatorial coordination of UO22+ in aragonite acid the dominant aqueous species [UO2(CO3)(3)(4-)] but a different coordination in calcite indicates that a change in UO22+ coordination is required for its incorporation into calcite. This may explain the observed preferential uptake of U(VI) by aragonite relative to calcite. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Seaborg Inst Transactinium Sci, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Reeder, RJ (reprint author), SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RI Morris, David/A-8577-2012 NR 35 TC 133 Z9 135 U1 10 U2 55 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 FEB 15 PY 2000 VL 34 IS 4 BP 638 EP 644 DI 10.1021/es990981j PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 284UY UT WOS:000085352300016 ER PT J AU Tiemann, KJ Gardea-Torresdey, JL Gamez, G Dokken, K Cano-Aguilera, I Renner, MW Furenlid, LR AF Tiemann, KJ Gardea-Torresdey, JL Gamez, G Dokken, K Cano-Aguilera, I Renner, MW Furenlid, LR TI Effects of oxidation state on metal ion binding by Medicago sativa (alfalfa): Atomic and X-ray absorption spectroscopic studies with Fe(II) and Fe(III) SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID HEAVY-METALS; REMOVAL AB We present here experimental results that investigate the effects of metal-ion binding on iron-ion sorption to and recovery from alfalfa biomass. Fe(II)- and Fe(III)-ion binding were measured in order to ascertain the differences in binding strengths due to changes in oxidation state. Stronger binding was found for iron(III)-biomass as compared to iron(II)-biomass. The optimal pH for iron uptake was determined to be 5. The results of pH binding profile, iron desorption, and temperature-dependent binding experiments as well as X-ray spectroscopic (XAS) measurements all suggest that binding of iron by alfalfa biomass may be occurring through carboxyl ligands. The XAS experiments further demonstrate that the metal binding proceeds without an oxidation state change, and both iron(II) and iron(III) have similar coordination environments. The information presented will assist in understanding the binding of other metals to alfalfa biomass and in developing methods for their recovery. C1 Univ Texas, Dept Chem & Environm Sci & Engn, El Paso, TX 79968 USA. Univ Guanajuato, Fac Quim, Guanajuato, Mexico. Brookhaven Natl Lab, Dept Appl Sci, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Gardea-Torresdey, JL (reprint author), Univ Texas, Dept Chem & Environm Sci & Engn, El Paso, TX 79968 USA. RI Gamez, Gerardo/C-9733-2011 OI Gamez, Gerardo/0000-0002-8827-6647 NR 25 TC 27 Z9 28 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 15 PY 2000 VL 34 IS 4 BP 693 EP 698 DI 10.1021/es9909071 PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 284UY UT WOS:000085352300024 ER PT J AU Smith, JS Tachibana, I Pohl, U Lee, HK Thanarajasingam, U Portier, BP Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN Jenkins, RB AF Smith, JS Tachibana, I Pohl, U Lee, HK Thanarajasingam, U Portier, BP Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN Jenkins, RB TI A transcript map of the chromosome 19q-arm glioma tumor suppressor region SO GENOMICS LA English DT Article ID EXON AMPLIFICATION; GENE; HETEROZYGOSITY; ASTROCYTOMAS; 19Q; OLIGODENDROGLIOMAS; PROGRESSION; CANDIDATE; CLONING AB Allelic loss of the chromosome 19q arm is a frequent event in human diffuse gliomas, suggesting that it contains a tumor suppressor gene. Recent deletion mapping studies have broadly implicated a 1.6-Mb interval between D19S241E and D19S596, with a limited subset of tumors, suggesting that the region may be as narrow as 150 kb. Focusing on this smaller interval, we have used cDNA selection, exon amplification, and genomic sequencing to identify three novel transcripts (EHD2, GLTSCR1, and GLTSCR2) and to map two known genes (SEPW1 and CRX). A partial transcript map of 19 transcripts and two EST markers has been constructed for the 1.6-Mb interval D19S241E-D19S596. Ten of these transcripts, including the 5 mapped to the 150-kb deletion interval, have been examined for alterations in a panel of gliomas with allelic loss of 19q. Tumor-specific alterations have not been identified in the transcripts examined thus far. Collectively, these data should facilitate subsequent efforts to identify and characterize the remaining transcripts in the 1.6-Mb interval, (C) 2000 Academic Press. C1 Mayo Clin & Mayo Fdn, Sch Med, Dept Cytogenet, Rochester, MN 55905 USA. Mayo Clin & Mayo Fdn, Dept Lab Med & Pathol, Div Lab Genet, Rochester, MN 55905 USA. Massachusetts Gen Hosp, Mol Neurooncol Lab, Dept Pathol Neuropathol, Charlestown, MA 02129 USA. Massachusetts Gen Hosp, Neurosurg Serv, Charlestown, MA 02129 USA. Harvard Univ, Sch Med, Charlestown, MA 02139 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, Livermore, CA 94550 USA. RP Jenkins, RB (reprint author), Mayo Clin & Mayo Fdn, Sch Med, Dept Cytogenet, 200 1st St,SW, Rochester, MN 55905 USA. RI imoto, Issei/D-8065-2012 FU NCI NIH HHS [CA 69285, CA 50905] NR 41 TC 86 Z9 92 U1 1 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 15 PY 2000 VL 64 IS 1 BP 44 EP 50 DI 10.1006/geno.1999.6101 PG 7 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 295VH UT WOS:000085988200005 PM 10708517 ER PT J AU Kim, J Bergmann, A Stubbs, L AF Kim, J Bergmann, A Stubbs, L TI Exon sharing of a novel human zinc-finger gene, ZIM2, and paternally expressed gene 3 (PEG3) SO GENOMICS LA English DT Article ID IMPRINTED GENE; SUBFAMILY; PROTEINS AB We have identified a novel human gene, ZIM2 (zinc-finger gene 2 from imprinted domain), located 25 kb downstream of PEG3 (paternally expressed gene 3), ZIM2 produces two different-size transcripts, 2.5 and 9.0 kb in length, with highest levels of expression in adult testis and modest levels in fetal kidney and brain. The 2.5-kb transcript of ZIM2 consists of 11 exons and encodes a Kruppel-type (C2H2) zinc-finger protein with a conserved Kruppel-associated box (KRAB) domain. Rapid amplification of cDNA ends and cDNA sequencing studies showed that ZIM2 and PEG3 transcripts share identical 5'-ends, composed of 7 small exons, Alternative splicing events connect these 7 exons either with the remaining 2 exons of PEG3 or with the remaining 4 exons of ZIM2. Interestingly, the third among the 7 shared exons exhibits sequence similarity to leucine-rich domains that are found at the N-terminal region of a subset of KRAB-containing zinc-finger genes. Sequencing of the 5'-termini of both transcripts indicates that ZIM2 and PEG3 share identical transcription start sites and may also share upstream regulatory elements, although the two genes show distinct patterns of tissue-specific expression. (C) 2000 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. DOE Joint Genome Inst, Walnut Creek, CA 94598 USA. RP Kim, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, Biol & Biotechnol Res Program, L-451,7000 East Ave, Livermore, CA 94551 USA. OI Stubbs, Lisa/0000-0002-9556-1972 NR 14 TC 37 Z9 38 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 15 PY 2000 VL 64 IS 1 BP 114 EP 118 DI 10.1006/geno.1999.6112 PG 5 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 295VH UT WOS:000085988200014 PM 10708526 ER PT J AU Borkowski, M Choppin, GR Moore, RC Free, SJ AF Borkowski, M Choppin, GR Moore, RC Free, SJ TI Thermodynamic modeling of metal-ligand interactions in high ionic strength NaCl solutions: the Co2+-citrate and Ni2+-citrate systems SO INORGANICA CHIMICA ACTA LA English DT Article DE cobalt complexes; nickel complexes; citrate complexes ID STABILITY-CONSTANTS; NATURAL-WATERS; COMPLEXES; 25-DEGREES-C; COEFFICIENTS; PARAMETERS; PREDICTION AB The complexation of Co(II) and Ni(II) by citrate in 0.3-5 m NaCl solutions has been investigated. The stability constants for CoCit(-) and NiCit(-) were measured as a function of NaCl concentration using a solvent extraction method with HDEHP in toluene. The stability constants for both complexes decreased with increasing NaCl concentrations up to 5 m. The data were modeled using the ion-interaction formalism developed by Pitzer. The dimensionless standard chemical potentials for the CoCit(-) and NiCit(-) complexes were calculated to be - 2.561 and - 0.697, respectively. Binary interaction parameters calculated in this work were beta(0) = - 0.2249 and C-Phi = 0.0539 for NiCit(-) and Na+ interactions and beta(0) = - 0.5407 and C-Phi = 0.1353 for CoCit(-) and Na+ interactions. Because of limited data, the B-(1) value for both CoCit(-) and NiCit(-) with Na+ was fixed at an average value of 0.29 which was obtained by averaging 1-1 interactions for other carboxylic acid salts. Higher order interaction parameters wen not required to model the data. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. Sandia Natl Labs, Albuquerque, NM 87187 USA. RP Choppin, GR (reprint author), Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. NR 17 TC 7 Z9 7 U1 0 U2 10 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 FEB 15 PY 2000 VL 298 IS 2 BP 141 EP 145 DI 10.1016/S0020-1693(99)00421-1 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 280UK UT WOS:000085122000002 ER PT J AU Mahan, AH Gedvilas, LM Webb, JD AF Mahan, AH Gedvilas, LM Webb, JD TI Si-H bonding in low hydrogen content amorphous silicon films as probed by infrared spectroscopy and x-ray diffraction SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HOT-WIRE TECHNIQUE; A-SI; VIBRATIONAL-SPECTRA; GLOW-DISCHARGE; DEVICE QUALITY; DEPOSITION; ALLOYS AB A systematic series of hydrogenated amorphous silicon (a-Si:H films) has been deposited by the hot wire chemical vapor deposition (HWCVD) technique onto crystalline silicon substrates, and the H bonding has been examined by infrared spectroscopy. All deposition parameters were kept the same, except that the substrate temperature (T-S) was varied to affect changes in the film H content. Although the peak position of the Si-H stretch mode changes minimally with increasing substrate temperature, the stretch mode shape changes, becoming more intense (compared to the height of the wag mode) and considerably narrower. We show, through annealing experiments, that this narrow stretch mode may be a universal feature of low H content films, and suggest interpretations for this finite (narrow) linewidth. By correlations with x-ray diffraction data, we also show that the narrowing of the stretch mode peak for low H content HWCVD films is an indication of improved lattice ordering, and suggest that this improved ordering might also exist for other types of low H content a-Si:H films as well. However, for the as-grown HWCVD films the narrowing of the stretch mode peak width at lower H contents does not completely compensate for the increase in peak height, and as a result the integrated intensity of the peak mode (relative to that of the wag mode) increases. We comment on the differences between as-grown, low H content a-Si:H HWCVD films and high H content films annealed to reduce the film H content to comparable levels, and discuss possible reasons for these intensity changes versus sample H content. (C) 2000 American Institute of Physics. [S0021-8979(00)00704-0]. C1 NREL, Golden, CO 80401 USA. RP Mahan, AH (reprint author), NREL, 1617 Cole Blvd, Golden, CO 80401 USA. NR 49 TC 40 Z9 40 U1 0 U2 9 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 FEB 15 PY 2000 VL 87 IS 4 BP 1650 EP 1658 DI 10.1063/1.372073 PG 9 WC Physics, Applied SC Physics GA 278MA UT WOS:000084992500010 ER PT J AU Han, DX Yue, GZ Lorentzen, JD Lin, J Habuchi, H Wang, Q AF Han, DX Yue, GZ Lorentzen, JD Lin, J Habuchi, H Wang, Q TI Optical and electronic properties of microcrystalline silicon as a function of microcrystallinity SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID AMORPHOUS-SILICON; GRAIN-BOUNDARIES; FILMS; ABSORPTION AB Films were prepared by hot wire chemical vapor deposition at similar to 240 degrees C with varied hydrogen dilution ratios R = H-2:SiH4 from 1 to 20. The optical and electronic properties as a function of microcrystallinity were studied. We found: (a) At low H dilution R less than or equal to 2, there is no measurable crystallinity by Raman spectroscopy and x-ray diffraction in the a-Si:H matrix, but an optical absorption peak at similar to 1.25 eV appears; when R = 2, the film shows the lowest subgap absorption, the highest photosensitivity, and the largest optical gap. (b) When R greater than or equal to 3, the c-Si phase is measurable by Raman and a low-energy photoluminescence (PL) band (0.84-1.0 eV) appears in addition to the high-energy band (1.3-1.4 eV). Meanwhile, all the absorption spectra show a featureless line shape. (c) An energy redshift is observed for both PL peaks as the film grows thicker. Finally, (d) the conductivity activation energy first decreases from 0.68 to 0.12 eV, then increases with increasing microcrystallinity. A mode of two sets of energy bands of electronic states for these two-phase materials is suggested. (C) 2000 American Institute of Physics. [S0021-8979(00)00104-3]. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Gifu Natl Coll Technol, Sinsei, Gifu 5010495, Japan. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Han, DX (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NR 22 TC 68 Z9 71 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 FEB 15 PY 2000 VL 87 IS 4 BP 1882 EP 1888 DI 10.1063/1.372108 PG 7 WC Physics, Applied SC Physics GA 278MA UT WOS:000084992500045 ER PT J AU Crone, BK Davids, PS Campbell, IH Smith, DL AF Crone, BK Davids, PS Campbell, IH Smith, DL TI Device model investigation of bilayer organic light emitting diodes SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHARGE-CARRIER RECOMBINATION; ELECTROLUMINESCENT DIODES; CONJUGATED POLYMERS; MOBILITY; DEPENDENCE; VINYLENE); ELECTRON AB Organic materials that have desirable luminescence properties, such as a favorable emission spectrum and high luminescence efficiency, are not necessarily suitable for single layer organic light-emitting diodes (LEDs) because the material may have unequal carrier mobilities or contact limited injection properties. As a result, single layer LEDs made from such organic materials are inefficient. In this article, we present device model calculations of single layer and bilayer organic LED characteristics that demonstrate the improvements in device performance that can occur in bilayer devices. We first consider an organic material where the mobilities of the electrons and holes are significantly different. The role of the bilayer structure in this case is to move the recombination away from the electrode that injects the low mobility carrier. We then consider an organic material with equal electron and hole mobilities but where it is not possible to make a good contact for one carrier type, say electrons. The role of a bilayer structure in this case is to prevent the holes from traversing the device without recombining. In both cases, single layer device limitations can be overcome by employing a two organic layer structure. The results are discussed using the calculated spatial variation of the carrier densities, electric field, and recombination rate density in the structures. (C) 2000 American Institute of Physics. [S0021-8979(00)06504-X]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Crone, BK (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Davids, Paul/D-1550-2010 NR 25 TC 109 Z9 111 U1 2 U2 19 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 FEB 15 PY 2000 VL 87 IS 4 BP 1974 EP 1982 DI 10.1063/1.372123 PG 9 WC Physics, Applied SC Physics GA 278MA UT WOS:000084992500060 ER PT J AU Batista, ER Xantheas, SS Jonsson, H AF Batista, ER Xantheas, SS Jonsson, H TI Electric fields in ice and near water clusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISTRIBUTED MULTIPOLE ANALYSIS; AB-INITIO; DIPOLE-MOMENT; LIQUID WATER; POTENTIAL FUNCTIONS; MOLECULAR-DYNAMICS; WAVE-FUNCTIONS; ABINITIO; SPECTROSCOPY; SIMULATION AB We have studied the electric field near water clusters and in ice Ih using first principles calculations. We employed Moller-Plesset perturbation theory (MP2) for the calculations of the clusters up to and including the hexamer, and density functional theory (DFT) with a gradient dependent functional [Perdew-Wang (PW91)] for ice Ih as well as the clusters. The electric field obtained from the first principles calculations was used to test the predictions of an induction model based on single center multipole moments and polarizabilities of an isolated water molecule. We found that the fields obtained from the induction model agree well with the first principles results when the multipole expansion is carried out up to and including the hexadecapole moment, and when polarizable dipole and quadrupole moments are included. This implies that accurate empirical water interaction potential functions transferable to various environments such as water clusters and ice surfaces could be based on a single center multipole expansion carried out up to the hexadecapole. Since point charges are not included, the computationally intensive Ewald summations can be avoided. Molecular multipole moments were also extracted from the first principles charge density using zero flux dividing surfaces as proposed by Bader. Although the values of the various molecular multipoles obtained with this method are quite different from the ones resulting from the induction model, the rate of convergence of the electric field is, nevertheless, quite similar. (C) 2000 American Institute of Physics. [S0021-9606(00)52505-7]. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Univ Washington, Dept Phys, POB 351560, Seattle, WA 98195 USA. EM sotiris.xantheas@pnl.gov; hannes@u.washington.edu RI Jonsson, Hannes/G-2267-2013; Xantheas, Sotiris/L-1239-2015; OI Jonsson, Hannes/0000-0001-8285-5421; Xantheas, Sotiris/0000-0002-6303-1037 NR 55 TC 49 Z9 49 U1 0 U2 14 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 2000 VL 112 IS 7 BP 3285 EP 3292 DI 10.1063/1.480912 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 280HW UT WOS:000085097300022 ER PT J AU Parks, EK Kerns, KP Riley, SJ AF Parks, EK Kerns, KP Riley, SJ TI The binding of CO to nickel clusters. I. Determination of saturation coverages SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHASE METAL-CLUSTERS; CARBON-MONOXIDE; MOLECULAR NITROGEN; ADSORPTION; SURFACE; CHEMISORPTION; PHOTOEMISSION; NI(100) AB The reactions of small nickel clusters Ni-n (n = 3-60) with carbon monoxide are studied in a gas-phase flow-tube reactor. Cluster coverage is determined as a function of CO pressure at temperatures between -160 and 20 degrees C. The reactions are kinetically controlled under these conditions, but the CO uptake is characterized by a transition from a fast kinetics to a slow kinetics process. Sticking probabilities in the fast kinetics region are near unity at low temperature. The coverage at the transition is consistent with random filling of the cluster surface with van der Waals CO molecules in a standing up configuration with the carbon end toward the metal. Higher coverages in most cases are a consequence of changes in nickel cluster structure to more open ones having larger surface areas. (C) 2000 American Institute of Physics. [S0021-9606(00)00806-0]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Parks, EK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 41 TC 24 Z9 24 U1 1 U2 10 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 FEB 15 PY 2000 VL 112 IS 7 BP 3384 EP 3393 DI 10.1063/1.480920 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 280HW UT WOS:000085097300031 ER PT J AU Kerns, KP Parks, EK Riley, SJ AF Kerns, KP Parks, EK Riley, SJ TI The binding of CO to nickel clusters. II. Structural implications and comparisons with electron counting rules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID METAL-CLUSTERS; CHEMICAL CHARACTERIZATION; BONDING CAPABILITIES; INORGANIC OLIGOMERS; CARBONYL CLUSTERS; MOLECULAR-BEAMS; NI-N; MAGNETISM; DIANIONS; MONOXIDE AB The saturation levels of small nickel clusters Ni-n (n =2-20) with CO are determined. Modeling of the CO-covered clusters shows that in almost all cases saturation is governed by the geometrical sizes of the nickel clusters and the van der Waals size of the CO molecules. While electron counting rules, along with an assumed cluster structure, can predict saturation levels, the predictions generally overestimate the levels based on geometry. In the case of the smallest clusters (n less than or equal to 13), CO adsorption appears to cause changes in structure to more open ones that result in increased adsorption, giving coverages close to the electron counting rule predictions for the bare cluster geometries. Larger clusters, with internal metal atoms, seem to be more resistant to structural changes. Comparisons with earlier studies of nickel cluster positive and negative ions are made and the significance of a short reaction time scale on the nature of the reaction products is discussed. (C) 2000 American Institute of Physics. [S0021-9606(00)00906-5]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Kerns, KP (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 41 TC 28 Z9 28 U1 1 U2 9 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 FEB 15 PY 2000 VL 112 IS 7 BP 3394 EP 3407 DI 10.1063/1.480499 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 280HW UT WOS:000085097300032 ER PT J AU O'Day, PA Newville, M Neuhoff, PS Sahai, N Carroll, SA AF O'Day, PA Newville, M Neuhoff, PS Sahai, N Carroll, SA TI X-ray absorption spectroscopy of strontium(II) coordination - I. Static and thermal disorder in crystalline, hydrated, and precipitated solids and in aqueous solution SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE X-ray absorption spectroscopy; EXAFS; strontium; anharmonic disorder; cumulant expansion; zeolite ID MULTIPLE-SCATTERING CALCULATIONS; MOLECULAR-DYNAMICS SIMULATIONS; FINE-STRUCTURE; EXAFS ANALYSIS; K-EDGE; HEULANDITE; XAFS; IONS; CLINOPTILOLITE; DEHYDRATION AB Detailed analyses of crystalline, hydrated, and precipitated strontium compounds and an aqueous strontium solution by synchrotron extended X-ray absorption fine structure (EXAFS) were used to quantify local thermal and static disorder and to characterize strontium coordination in a variety of oxygen-ligated bonding environments. Analysis of anharmonic vibrational disorder (i.e., significant contribution from a third cumulant term (C-3) in the EXAFS phase-shift function) in compounds with low and high static disorder around strontium showed that first-shell anharmonic contributions were generally not significant above experimental error in the EXAFS fits (R +/- 0.02 Angstrom with and without C-3) The only case in which a significant apparent decrease in Sr-O distance was observed with increasing temperature, and for which a third cumulant term was significant, was for dilute strontium in aqueous solution. Empirical parameterization of Debye-Waller factor (sigma(2)) for strontium compounds as a function of backscatterer atomic number (Z), interatomic Sr-Z distance, and temperature of spectral data collection showed systematic increases in sigma(2) as a function of increasing temperature and Sr-Z bond length. At values of sigma(2) greater than approximate to 0.025 Angstrom(2) (for N < 12 and RSr-Z > 3 Angstrom), backscattering was generally not significant above noise levels in spectra of compounds of known crystal structure. Comparison of the EXAFS spectra of freshly precipitated SrCO3 (spectra collected wet) to that of dry, powdered strontianite (SrCO3(s)) indicated no significant differences in the local atomic structure around strontium. Analysis of partially hydrated strontium in natural Ca-zeolite (heulandite) showed that strontium is substituted only in the calcium (Ca2) site. Backscattering from aluminum and silicon atoms in the zeolite framework were apparent in the EXAFS spectra at low and room temperature at distances from central strontium of <4.2 Angstrom. Comparison of strontium structural coordination determined in this and previous studies suggests that previous EXAFS determinations of hydrated strontium may have underestimated first-shell interatomic distances and coordination numbers because minor contributions to the EXAFS phase-shift and amplitude functions were not accounted for, either theoretically or empirically. (C) 2000 Academic Press. C1 Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Univ Chicago, Consortium Adv Radiat Sources, Chicago, IL 60637 USA. Stanford Univ, Dept Geog & Environm Sci, Stanford, CA 94305 USA. Lawrence Livermore Natl Lab, Earth & environm Sci Directorate, Livermore, CA 94550 USA. RP O'Day, PA (reprint author), Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. EM oday@asu.edu NR 47 TC 56 Z9 56 U1 3 U2 23 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 EI 1095-7103 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD FEB 15 PY 2000 VL 222 IS 2 BP 184 EP 197 DI 10.1006/jcis.1999.6621 PG 14 WC Chemistry, Physical SC Chemistry GA 289TX UT WOS:000085639000005 ER PT J AU Sahai, N Carroll, SA Roberts, S O'Day, PA AF Sahai, N Carroll, SA Roberts, S O'Day, PA TI X-ray absorption spectroscopy of strontium(II) coordination - II. Sorption and precipitation at kaolinite, amorphous silica, and goethite surfaces SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE strontium; kaolinite; goethite; amorphous silica; outer-sphere; hydration; sorption; precipitation; EXAFS; strontianite ID MULTIPLE-SCATTERING CALCULATIONS; HYDROUS FERRIC-OXIDE; CRYSTAL-STRUCTURE; ION ADSORPTION; FINE-STRUCTURE; CLAY-MINERALS; CESIUM; COMPLEXATION; MECHANISM; BEHAVIOR AB Sorption of dissolved strontium on kaolinite, amorphous silica, and goethite was studied as a function of pH, aqueous strontium concentration, the presence or absence of atmospheric CO2 or dissolved phosphate, and aging over a 57-day period. Selected sorption samples ([Sr(aq)](i) approximate to 0.5-1 x 10(-3) m) were examined with synchrotron X-ray absorption spectroscopy (XAS) at low (13-23 K)and room temperatures to determine the local molecular coordination around strontium, Quantitative analyses of the extended X-ray absorption fine structure (EXAFS) of kaolinite, amorphous silica, and most goethite sorption samples showed a single first shell of 9-10 (+/-1) oxygen atoms around strontium at an average Sr-O bond-distance of 2.61 (+/-0.02) Angstrom, indicating hydrated surface complexes. The EXAFS spectra were unchanged after reaction for up to 57 days. Likewise, in kaolinite sorption samples prepared in 100% nitrogen atmosphere, the presence of dissolved phosphate (0.5 x 10(-3) m) in addition to strontium did not change the local coordination around strontium. In two goethite sorption samples reacted in air at pH similar to 8.5, the EXAFS spectra (collected at low and room temperature) clearly showed that the local structure around strontium is that of strontianite (SrCO3(s)), We also noted an increase in strontium uptake on goethite in the presence of atmospheric CO2 in batch experiments, relative to CO2-free experiments. These observations suggest that sorption of carbonate may nucleate the precipitation of SrCO3 in the pH range in which carbonate sorption on goethite is near a maximum. At higher pH, carbonate surface sorption decreases as dissolved CO2 decreases. For goethite sorption samples above pH 8.6, hydrated surface complexes, rather than a precipitate, were observed in the EXAFS spectra. (C) 2000 Academic Press. C1 Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Lawrence Livermore Natl Lab, Earth & Environm Sci Directorate, Livermore, CA 94550 USA. RP O'Day, PA (reprint author), Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. EM oday@asu.edu NR 59 TC 91 Z9 91 U1 8 U2 47 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 EI 1095-7103 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD FEB 15 PY 2000 VL 222 IS 2 BP 198 EP 212 DI 10.1006/jcis.1999.6562 PG 15 WC Chemistry, Physical SC Chemistry GA 289TX UT WOS:000085639000006 ER PT J AU Thompson, HA Parks, GA Brown, GE AF Thompson, HA Parks, GA Brown, GE TI Formation and release of cobalt(II) sorption and precipitation products in aging kaolinite-water slurries SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE adsorption; aging; desorption; dissolution; EXAFS; hydrotalcite; precipitation; ripening; solid solution; stability ID RAY-ABSORPTION-SPECTROSCOPY; ADSORPTION-DESORPTION BEHAVIOR; GOETHITE-SOLUTION INTERFACE; GAMMA-AL2O3 SURFACE; ANION-EXCHANGE; METAL SORPTION; KINETICS; COMPLEXES; CLAYS; IONS AB The uptake and release behavior of cobalt(II) was studied over thousands of hours in CO2-free aqueous suspensions of kaolinite under three pairs of total cobalt concentration (Co-T) and near-neutral pH (7.5-7.8) conditions. Dissolved cobalt, aluminum, and silicon concentrations were monitored by ICPMS, and cobalt-containing products were identified by EXAFS spectroscopy. In each uptake experiment, cobalt sorbed to kaolinite as a mixture of surface-adsorbed monomers or polymers and hydrotalcite-like precipitates of the approximate composition CoxAl(OH)(2x+2)(A(n-))(1/n), where 2 less than or equal to x less than or equal to 4 and A(n-) is nitrate or silicate anion, Precipitate stoichiometry varied with experimental conditions, with the highest Co:Al ratio in the high Co-T/high pH experiment. Cobalt surface adsorption occurred within seconds, whereas precipitation was slower and continued for the duration of the experiments. Consequently, the proportion of precipitate in the sorbed mixture increased with time in all experiments. The most rapid precipitation occurred in the high Co-T/high pH experiment, where solutions were most supersaturated with respect to cobalt hydrotalcite. Precipitates incorporated some previously adsorbed cobalt, as well as cobalt from solution. Cobalt release from the solid phase was effected by lowering solution pH to 7.0. Release experiments initiated after shorter sorption times returned a larger fraction of cobalt to solution than those initiated after longer sorption times, for a fixed duration of release. In other words, sorption product stability increased with sorption time. Specifically, under the conditions of the release experiments, the hydrotalcite-like precipitates are more stable than smaller adsorbates, and precipitates that formed over longer time periods are more stable than those that formed rapidly. The latter result suggests that precipitates ripened or modified their structure or composition to become more stable over the course of the several-thousand-hour sorption experiments. Precipitates that formed over hundreds of hours or longer did not dissolve over thousands of hours at the lower pH. (C) 2000 Academic Press. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Thompson, HA (reprint author), Univ Calif Los Alamos Natl Lab, MS J586, Los Alamos, NM 87545 USA. NR 34 TC 30 Z9 30 U1 1 U2 11 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD FEB 15 PY 2000 VL 222 IS 2 BP 241 EP 253 DI 10.1006/jcis.1999.6631 PG 13 WC Chemistry, Physical SC Chemistry GA 289TX UT WOS:000085639000010 ER PT J AU Whelan, G McDonald, JP Taira, RY Gnanapragasam, EK Yu, C Lew, CS Mills, WB AF Whelan, G McDonald, JP Taira, RY Gnanapragasam, EK Yu, C Lew, CS Mills, WB TI Source-term development for a contaminant plume for use by multimedia risk assessment models SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE multimedia modeling; conceptual site model; risk assessment; groundwater modeling; source-term modeling ID BENCHMARKING ANALYSIS; MEPAS; MMSOILS; RESRAD AB Multimedia modelers from the US Environmental Protection Agency (EPA) and US Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: MEPAS, MMSOILS, PRESTO, and RESRAD. These models represent typical analytically based tools that are used in human-risk and endangerment assessments at installations containing radioactive and hazardous contaminants, The objective is to demonstrate an approach for developing an adequate source term by simplifying an existing, real-world, Sr-90 plume at DOE's Hanford installation in Richland, WA, for use in a multimedia benchmarking exercise between MEPAS, MMSOILS, PRESTO, and RESRAD.:Source characteristics and a release mechanism are developed and described; also described is a typical process and procedure that an analyst would follow in developing a source term for using this class of analytical tool in a preliminary assessment. (C) 2000 Elsevier Science B.V; All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Tetra Tech, Lafayette, CA USA. RP Whelan, G (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 29 TC 3 Z9 3 U1 0 U2 0 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 FEB 15 PY 2000 VL 41 IS 3-4 BP 205 EP 223 DI 10.1016/S0169-7722(99)00066-2 PG 19 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 279FV UT WOS:000085034500001 ER PT J AU Kwon, YK Annis, BK Chen, W Wunderlich, B AF Kwon, YK Annis, BK Chen, W Wunderlich, B TI Equilibrium short-range order in the isotropic phase of a poly(ester-imide) with a C22H44 alkane spacer SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE poly(ester-imide); nanophase; DSC; wide- and small-angle X-ray scattering ID STATE C-13 NMR; X = BR; ALKYLAMMONIUM SALTS; MESOPHASES; MOTION; CRYSTALLIZATION; TRANSITIONS; SCATTERING; POLYIMIDES; DISORDER AB Small-angle X-ray scattering (SAXS) was performed on a sample of poly(4,4'- phthaloimidobenzoyldoeicosamethyleneoxycarbonyl) (PEIM-22) as a function of temperature. Wide-angle X-ray diffraction and differential scanning calorimetry were used to follow the isotropization of the crystalline PEIM-22. The crystals of PEIM-22 consist of biphasic layers up to the isotropization temperature. A series of SAXS peaks are observed for the crystals between theta = 0.3 and 3.5 degrees. The width of these peaks indicates the formation of a smectic-like, crystalline layer structure of a coherently scattering domain size of only 3-4 repeating units. In the isotropic phase, a single, broader peak remained at a spacing of approximate to 2.6 nm, suggesting even at high temperature the existence of equilibrium, short-range, local order. The SAXS profiles were calculated based on a model of alternating layers of a linear, paracrystalline lattice. The results were discussed together with similar data on model compounds in the literature, and it is suggested that the short-range order in the isotropic phase is due to a nanometer-scale separation of the polar, aromatic phthaloimidobenzoyl from the flexible doeicosamethyleneoxycarbonyl. (C) 2000 John Wiley & Sons, Inc. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 41 TC 2 Z9 2 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD FEB 15 PY 2000 VL 38 IS 4 BP 611 EP 621 DI 10.1002/(SICI)1099-0488(20000215)38:4<611::AID-POLB13>3.0.CO;2-0 PG 11 WC Polymer Science SC Polymer Science GA 279VU UT WOS:000085066400013 ER PT J AU Pyda, M Wunderlich, B AF Pyda, M Wunderlich, B TI Reversible and irreversible heat capacity of poly(trimethylene terephthalate) analyzed by temperature-modulated differential scanning calorimetry SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE poly(trimethylene terephthalate); heat capacity; reversible melting; temperature-modulated differential scanning calorimetry (TMDSC); irreversible melting ID GLASS-TRANSITION REGION; POLYMER CRYSTALS; POLYSTYRENE AB The heat capacity of poly(trimethylene terephthalate) (PTT) has been analyzed using temperature-modulated differential scanning calorimetry (TMDSC) and compared with results obtained earlier from adiabatic calorimetry and standard differential scanning calorimetry (DSC). Using quasi-isothermal TMDSC, the apparent reversing and nonreversing heat capacities were determined from 220 to 540 K, including glass and melting transitions. Truly reversible and time-dependent irreversible heat effects were separated. The extrapolated vibrational heat capacity of the solid and the total heat capacity of the liquid served as baselines for the analysis. As one approaches the melting region from lower temperature, semicrystalline PTT shows a reversing heat capacity, which is larger than that of the liquid, an observation that is common also for other polymers. This higher heat capacity is interpreted as a reversible surface or bulk melting and crystallization, which does not need to undergo molecular nucleation. Additional time-dependent, reversing contributions, dominating at temperatures even closer to the melting peak, are linked to reorganization and recrystallization (annealing), while the major melting is fully irreversible (nonreversing contribution). (C) 2000 John Wiley & Sons, Inc. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 44 TC 73 Z9 73 U1 3 U2 15 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD FEB 15 PY 2000 VL 38 IS 4 BP 622 EP 631 DI 10.1002/(SICI)1099-0488(20000215)38:4<622::AID-POLB14>3.3.CO;2-L PG 10 WC Polymer Science SC Polymer Science GA 279VU UT WOS:000085066400014 ER PT J AU Stevens, DE Bell, JB Almgren, AS Beckner, VE Rendleman, CA AF Stevens, DE Bell, JB Almgren, AS Beckner, VE Rendleman, CA TI Small-scale processes and entrainment in a stratocumulus marine boundary layer SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NAVIER-STOKES EQUATIONS; INSTABILITY; SIMULATIONS; PROJECTION; MODELS; FLOW AB Numerical studies of boundary layer meteorology are increasingly reliant on large eddy simulation (LES) models, but few detailed validation studies of these types of models have been done. In this paper the authors investigate the behavior of an LES model for simulation of a marine boundary layer. Specifically, the authors focus on the mechanisms that control numerical predictions of entrainment into the tops of marine stratus in a moist generalization of the 1995 Global Energy and Water Cycle Experiment Cloud System Studies model intercomparison. For the computational study the authors present a sequence of simulations of varying resolution, from a typical resolution (50 m horizontal and 25 m vertical mesh size) to a fine resolution (8 m horizontal and 4 m vertical mesh size). The authors also explore variations in the model such as different subgrid models and modifications of the advection scheme. It was found that the thickness of the inversion, the depth of entraining eddies, and the shape of vertical velocity spectra were determined mainly by the mesh spacing used. However, the entrainment rate was found to have a distinct dependence on the amount of combined numerical and subgrid-scale mixing. This indicates that the use of large eddy simulation to study mixing in stratocumulus boundary layers needs to account for both sources of mixing. C1 Univ Calif Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94551 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Comp Sci, Berkeley, CA 94720 USA. RP Stevens, DE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Div Atmospher Sci, L-103, Livermore, CA 94551 USA. NR 27 TC 13 Z9 13 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD FEB 15 PY 2000 VL 57 IS 4 BP 567 EP 581 DI 10.1175/1520-0469(2000)057<0567:SSPAEI>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 301MR UT WOS:000086314400008 ER PT J AU Schlamp, S Cummings, EB Sobota, TH AF Schlamp, S Cummings, EB Sobota, TH TI Laser-induced thermal-acoustic velocimetry with heterodyne detection SO OPTICS LETTERS LA English DT Article AB Laser-induced thermal acoustics (LITA) was used with heterodyne detection to measure simultaneously and in a single laser pulse the sound speed and flow velocity of NO2-seeded air in a low-speed wind tunnel up to Mach number M = 0.1. The uncertainties of the velocity and the sound speed measurements were similar to 0.2 m/s and 0.5% respectively. Measurements were obtained through a nonlinear least-squares fit to a general, analytic closed-form solution for heterodyne-detected LITA signals from thermal gratings. Agreement between theory and experiment is exceptionally good. (C) 2000 Optical Society of America OCIS codes: 000.2170, 050.2770, 120.6780, 120.7280, 190.4380. C1 CALTECH, Grad Aeronaut Labs, Pasadena, CA 91125 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Adv Projects Res Inc, La Verne, CA 91750 USA. RP Schlamp, S (reprint author), CALTECH, Grad Aeronaut Labs, Pasadena, CA 91125 USA. RI Schlamp, Stefan/A-9143-2008 OI Schlamp, Stefan/0000-0002-9933-3096 NR 10 TC 26 Z9 26 U1 2 U2 4 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 FEB 15 PY 2000 VL 25 IS 4 BP 224 EP 226 DI 10.1364/OL.25.000224 PG 3 WC Optics SC Optics GA 284FB UT WOS:000085319200012 PM 18059836 ER PT J AU Sankaran, V Walsh, JT Maitland, DJ AF Sankaran, V Walsh, JT Maitland, DJ TI Polarized light propagation through tissue phantoms containing densely packed scatterers SO OPTICS LETTERS LA English DT Article ID MEDIA; PARTICLES; CORNEA AB We demonstrate that polarized light is maintained differently in densely packed versus dilute suspensions of polystyrene microspheres. The degrees of linear and circular polarization were measured versus scatterer concentration in aqueous suspensions of 0.48-, 0.99-, 2.092-, and 9.14-mu m-diameter polystyrene microspheres. The results indicate that, for dilute suspensions of microspheres where independent scattering is assumed, the degrees of linear and circular polarization decrease as the scatterer concentration increases. For dense suspensions, however, the degree of polarization begins to increase as the scatterer concentration increases. The preferential propagation of linear over circular polarization states in dense suspensions is similar to results seen in biological tissue. (C) 2000 Optical Society of America OCIS codes: 170.3660, 170.7050, 260.5430, 290.4210. C1 Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94551 USA. Northwestern Univ, Dept Biomed Engn, Evanston, IL 60208 USA. RP Sankaran, V (reprint author), Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94551 USA. EM sankaran1@llnl.gov RI Walsh, Joseph/B-7636-2009 NR 16 TC 45 Z9 45 U1 0 U2 1 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 FEB 15 PY 2000 VL 25 IS 4 BP 239 EP 241 DI 10.1364/OL.25.000239 PG 3 WC Optics SC Optics GA 284FB UT WOS:000085319200017 PM 18059841 ER PT J AU Gotter, R Siu, WK Bartynski, RA Hulbert, SL Wu, XL Zitnik, M Nozoye, H AF Gotter, R Siu, WK Bartynski, RA Hulbert, SL Wu, XL Zitnik, M Nozoye, H TI Core-valence coupling in the Ru 4p photoexcitation/Auger decay process: Auger-photoelectron coincidence spectroscopy study SO PHYSICAL REVIEW B LA English DT Article ID COSTER-KRONIG; SPECTRA; METALS; RATES; NB AB The N23VV Auger spectrum of Ru has been measured in coincidence with 4p(1/2) and with 4p(3/2) photoelectrons, Unlike other metals that exhibit bandlike Auger decays, we find that the two Auger spectra are not shifted by-the difference in core level binding energies, A consistent description of these transitions and the core level line shape requires consideration of the relativistic multiplet splitting in the intermediate core hole state and two-valence-hole Auger final state. The results suggest that the large linewidth of the 4p levels is primarily due to multiplet splitting, and that an N-2(N3N45)N45N45 super-Coster-Kronig transition is only a minor decay channel. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Rutgers State Univ, Surface Modificat Lab, Piscataway, NJ 08855 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Ljubljana, Jozef Stefan Inst, Ljubljana 61000, Slovenia. Natl Inst Mat & Chem, Tsukuba, Ibaraki, Japan. RP Bartynski, RA (reprint author), Rutgers State Univ, Dept Phys & Astron, POB 849, Piscataway, NJ 08855 USA. EM bart@physics.rutgers.edu NR 20 TC 4 Z9 4 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 FEB 15 PY 2000 VL 61 IS 7 BP 4373 EP 4376 DI 10.1103/PhysRevB.61.4373 PG 4 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200001 ER PT J AU Liu, SD Jayanthi, CS Wu, SY Qin, XR Zhang, ZY Lagally, MG AF Liu, SD Jayanthi, CS Wu, SY Qin, XR Zhang, ZY Lagally, MG TI Formation of chain and V-shaped structures in the initial stage growth of Si/Si(100) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI AD-DIMERS; SI(100) SURFACE; AB-INITIO; TOTAL-ENERGY; SI(001); BINDING; DIFFUSION; DYNAMICS; SILICON AB New growth structures (chain and V-shaped structures) have recently been observed in scanning tunneling microscopy studies of Si and Ge adatoms deposited on Si(100). We have studied the basic building block, the nature and the formation of these growth structures by using a combination of theoretical techniques including the O(N) nonoarthogonal tight-binding molecular dynamics and local analysis of the electronic structure. We find that the interplay between the binding energy, diffusion barrier, and temperature is the key to the formation of these structures. C1 Univ Louisville, Dept Phys, Louisville, KY 40292 USA. Univ Wisconsin, Madison, WI 53706 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Liu, SD (reprint author), Univ Louisville, Dept Phys, Louisville, KY 40292 USA. NR 27 TC 12 Z9 12 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 7 BP 4421 EP 4424 DI 10.1103/PhysRevB.61.4421 PG 4 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200013 ER PT J AU Zhang, Y Mascarenhas, A Xin, HP Tu, CW AF Zhang, Y Mascarenhas, A Xin, HP Tu, CW TI Valence-band splitting and shear deformation potential of dilute GaAs1-xNx alloys SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; ELECTROREFLECTANCE; LUMINESCENCE; GAASN; GAP AB The valence-band splitting in thin GaAs1-xNx (0.011 less than or equal to x less than or equal to 0.033) epilayers strained coherently by the GaAs substrate is observed in electroreflectance. This study reveals that the valence-band deformation potential does not follow the linear interpolation of those for GaAs and GaN, but shows a rather strong composition dependence with a surprising bowing in a small composition region of the alloy. These results contradict the currently held view that the conduction band is greatly altered but that the valence band is only weakly perturbed by dilute nitrogen doping of GaAs. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RP Zhang, Y (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 27 TC 53 Z9 55 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 7 BP 4433 EP 4436 DI 10.1103/PhysRevB.61.4433 PG 4 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200016 ER PT J AU Kim, Y Munteanu, FM Perry, CH Rickel, DG Simmons, JA Reno, JL AF Kim, Y Munteanu, FM Perry, CH Rickel, DG Simmons, JA Reno, JL TI Magnetic-field-induced charged exciton studies in a GaAs/Al0.3Ga0.7As single heterojunction SO PHYSICAL REVIEW B LA English DT Article ID GAAS/ALXGA1-XAS QUANTUM-WELLS; ELECTRON-GAS; GAAS; PHOTOLUMINESCENCE AB The magnetophotoluminescence (MPL) behavior of a GaAs/Al0.3Ga0.7As single heterojunction has been investigated to 60 T. We observed negatively charged singlet (X-s(-)) and triples (X-t(-)) exciton states that are formed at high magnetic fields beyond the v=1 quantum Hall state. The variation of the charged exciton binding energies are in good agreement with theoretical predictions. The MPL transition intensities for the X-s(-) and X-t(-) states showed variations (maxima and minima) at the v=1/3 and 1/5 fractional quantum Hall states as a consequence of a large reduction of electron-hole screening at these filling factors. C1 Univ Calif Los Alamos Natl Lab, High Field Magnet Lab, Los Alamos, NM 87545 USA. Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kim, Y (reprint author), Univ Calif Los Alamos Natl Lab, High Field Magnet Lab, POB 1663, Los Alamos, NM 87545 USA. NR 18 TC 26 Z9 26 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 FEB 15 PY 2000 VL 61 IS 7 BP 4492 EP 4495 DI 10.1103/PhysRevB.61.4492 PG 4 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200031 ER PT J AU Biswas, R Sigalas, MM Subramania, G Soukoulis, CM Ho, KM AF Biswas, R Sigalas, MM Subramania, G Soukoulis, CM Ho, KM TI Photonic band gaps of porous solids SO PHYSICAL REVIEW B LA English DT Article ID PERIODIC DIELECTRIC STRUCTURES; SPONTANEOUS EMISSION; COLLOIDAL CRYSTALS; WAVELENGTHS; SYSTEMS; LATTICE; SPHERES AB Colloidal inverse photonic crystals composed of ordered lattices of air spheres in a high dielectric background are found to have three-dimensional photonic gaps for face-centered cubic, hexgaonal close-packed, and double hexagonal close-packed stacking sequences. Conditions for the occurrence of the complete gap are a sufficient dielectric contrast and a geometry near close packed. Although the lower pseudogaps of these stacking sequences differ, the lowest stop band in the stacking direction is insensitive to the stacking sequence; hence their experimental reflection should be similar. Transmission calculations with structural disorder show the lower pseudogap is relatively unaffected but the higher gap, is very difficult to observe with moderate disorder. C1 Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Microelect Res Ctr, Ames, IA 50011 USA. RP Biswas, R (reprint author), Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. RI Soukoulis, Costas/A-5295-2008 NR 38 TC 52 Z9 60 U1 0 U2 8 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 FEB 15 PY 2000 VL 61 IS 7 BP 4549 EP 4553 DI 10.1103/PhysRevB.61.4549 PG 5 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200046 ER PT J AU Dilley, NR Bauer, ED Maple, MB Dordevic, S Basov, DN Freibert, F Darling, TW Migliori, A Chakoumakos, BC Sales, BC AF Dilley, NR Bauer, ED Maple, MB Dordevic, S Basov, DN Freibert, F Darling, TW Migliori, A Chakoumakos, BC Sales, BC TI Thermoelectric and optical properties of the filled skutterudite YbFe4Sb12 SO PHYSICAL REVIEW B LA English DT Article ID LATTICE THERMAL-CONDUCTIVITY; ANTIMONIDES; TRANSITION; LAFE4P12; EARTH; CEFE4SB12 AB Transport measurements, including magnetoresistivity, Hall resistivity, thermal conductivity, and thermopower, and an assessment of the dimensionless thermoelectric figure of merit ZT below room temperature are reported on a polycrystalline sample of the strongly correlated electron material YbFe4Sb12. Neutron diffraction measurements are presented, which reveal large amplitude thermal vibrations of the Yb ion, consistent with speculations that the ion is weakly bound in an oversized atomic "cage" formed in the skutterudite crystal structure. Infrared spectroscopy measurements reveal a resonance in the dissipative part of the optical conductivity sigma(1)(omega), which develops below T*approximate to 70 K, the characteristic temperature for the Yb ion valence fluctuations. The frequency dependence of the optical constants is suggestive of a hybridization band gap in the quasiparticle density of states at low temperatures. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif San Diego, Inst Pure & Appl Phys Sci, La Jolla, CA 92093 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Dilley, NR (reprint author), Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RI Bauer, Eric/D-7212-2011; Chakoumakos, Bryan/A-5601-2016; OI Chakoumakos, Bryan/0000-0002-7870-6543; Freibert, Franz/0000-0003-4434-3446 NR 31 TC 66 Z9 67 U1 0 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 FEB 15 PY 2000 VL 61 IS 7 BP 4608 EP 4614 DI 10.1103/PhysRevB.61.4608 PG 7 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200053 ER PT J AU Levine, G AF Levine, G TI Linear and nonlinear susceptibilities of a decoherent two-level system SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM AB The linear and nonlinear dynamical susceptibilities of a two-level system are calculated as it undergoes a transition to a decoherent state. Analogously to the Glover-Tinkham-Ferrell sum rule of superconductivity, spectral weight in the linear susceptibility is continuously transferred from a finite frequency resonance to nearly zero frequency, corresponding to a broken symmetry in the thermodynamic limit. In this respect, the behavior of the present model (the Mermin model) differs from the spin-boson model. The third order nonlinear susceptibility, corresponding to two-photon absorption, has an unexpected nonmonotonic behavior as a function of the environmental coupling, reaching a maximum within the decoherent phase of the model. Both linear and nonlinear susceptibilities may be expressed in a universal form. C1 Hofstra Univ, Dept Phys, Hempstead, NY 11550 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Levine, G (reprint author), Hofstra Univ, Dept Phys, Hempstead, NY 11550 USA. NR 10 TC 6 Z9 6 U1 1 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 FEB 15 PY 2000 VL 61 IS 7 BP 4636 EP 4643 DI 10.1103/PhysRevB.61.4636 PG 8 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200057 ER PT J AU Jones, MD Boettger, JC Albers, RC Singh, DJ AF Jones, MD Boettger, JC Albers, RC Singh, DJ TI Theoretical atomic volumes of the light actinides SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; HIGH-PRESSURES; DENSITY; METALS; CRYSTAL; PU; ELEMENTS; SYSTEMS; TH; PA AB The zero-pressure zero-temperature equilibrium volumes and bulk moduli are calculated for the light actinides Th through Pu using two independent all-electron, full-potential, electronic-structure methods: the full-potential linear augmented-plane-wave method and the linear combinations of Gaussinn-type orbitals-fitting function method. The results produced by these two distinctly different electronic-structure techniques are in good agreement with each other, but differ significantly from previously published calculations using the full-potential linear muffin-tin-orbital (FP-LMTO) method. The theoretically calculated equilibrium volumes are in some cases nearly 10% larger than the previous FP-LMTO calculations, bringing them much closer to the experimentally observed volumes. We also discuss the anomalous upturn in equilibrium volume seen experimentally for alpha-Pu. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. USN, Res Lab, Washington, DC 20375 USA. RP Jones, MD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Singh, David/I-2416-2012 NR 45 TC 89 Z9 92 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 FEB 15 PY 2000 VL 61 IS 7 BP 4644 EP 4650 DI 10.1103/PhysRevB.61.4644 PG 7 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200058 ER PT J AU Choi, IH Eom, SH Yu, PY AF Choi, IH Eom, SH Yu, PY TI Pressure-induced deep donor level in the chalcopyrite semiconductor alloy Ag0.25Cu0.75GaS2 SO PHYSICAL REVIEW B LA English DT Article ID RAMAN MODES; CUGAS2; DEPENDENCE; AGGAS2 AB We report the appearance of a deep donor in the photoluminescence spectra of the chalcopyrite semiconductor alloy Ag0.25Cu0.75GaS2 under hydrostatic pressures exceeding 5 GPa. The recombination peaks of this deep donor with accepters exhibit either zero or a small negative pressure coefficient. Our results suggest the existence of a deep donor level which is resonant with the conduction band at ambient pressure. C1 Chung Ang Univ, Dept Phys, Seoul 156756, South Korea. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Choi, IH (reprint author), Chung Ang Univ, Dept Phys, Seoul 156756, South Korea. NR 17 TC 3 Z9 3 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 FEB 15 PY 2000 VL 61 IS 7 BP 4689 EP 4692 DI 10.1103/PhysRevB.61.4689 PG 4 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200065 ER PT J AU Munteanu, FM Kim, Y Perry, CH Rickel, DG Simmons, JA Reno, JL AF Munteanu, FM Kim, Y Perry, CH Rickel, DG Simmons, JA Reno, JL TI Crossing behavior of the singlet and triplet state of the negatively charged magnetoexciton in a GaAs/Al0.55Ga0.45As quantum well SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; MAGNETIC-FIELDS; EXCHANGE INTERACTION; ELECTRON-GAS; HEAVY-HOLE; GAAS; EXCITONS; PHOTOLUMINESCENCE; SPECTROSCOPY; INTERRUPTION AB Polarized magnetophotoluminescence (MPL) measurements on a high-mobility delta-doped GaAs/Al0.55Ga0.45As single quantum well from 0 to 60 T at temperatures between 0.37 and 2.1 K are reported. In addition to the neutral heavy-hole magnetoexciton (X-0), the singlet (X-s(-)) and tripler (X-t(-)) states of the negatively charged magnetoexciton are observed in both polarizations. The energy-dispersive and time-resolved MPL data suggest that their development is fundamentally related to the formation of the neutral magnetoexciton. At a magnetic field of 40 T the singlet and the triplet states cross as a result of the role played by the higher Landau levels and higher-energy subbands in their energetic evolution, confirming theoretical predictions. We also observed the formation of two higher-energy peaks. One of them is completely right circularly polarized and its appearance can be considered a result of the electron-hole exchange interaction enhancement with an associated electron g factor of 3.7 times the bull; value. The other peak completely dominates the MPL spectrum at fields around 30 T. Its behavior with magnetic field and temperature indicates that it may be related to previous anomalies observed in the integer and fractional quantum Hall regimes. C1 Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Munteanu, FM (reprint author), Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, POB 1663, Los Alamos, NM 87545 USA. NR 41 TC 24 Z9 24 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 FEB 15 PY 2000 VL 61 IS 7 BP 4731 EP 4738 DI 10.1103/PhysRevB.61.4731 PG 8 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200072 ER PT J AU Ostanin, S Uzdin, VM Demangeat, C Wills, JM Alouani, M Dreysse, H AF Ostanin, S Uzdin, VM Demangeat, C Wills, JM Alouani, M Dreysse, H TI Effect of hydrogen on the interlayer exchange coupling in Fe/V superlattices SO PHYSICAL REVIEW B LA English DT Article ID INTERFACE; FILMS; MULTILAYERS; MONOLAYERS; SCATTERING; MAGNETISM; CLUSTERS; SYSTEMS; MOMENTS; LAYERS AB Electronic and magnetic structures of Fe/V superlattices with and without hydrogen in the vanadium spacer are investigated using a relativistic full-potential linear muffin-tin orbital method. We obtained short-range induced spin polarization in V as well as reduced Fe polarization at the Fe/V interface. The value of the magnetic moment induced on the vanadium atoms depends strongly on the distortion caused by the lattice mismatch and hydrogen loading whereas the total moment of the Fe and V interface layers remains almost unchanged. Hydrogenation of the V spacer leads to the decrease of the interface magnetic moment on the V atoms and to a reduction of the density of states (DOS) at the Fermi level. A low DOS could be one of the reasons for the experimental increase of the resistivity of the samples under hydrogen loading and leads to the disappearance of the antiferromagnetic exchange coupling in the Fe/(VH) superlattices for large hydrogen concentration. Doping the V film by a gold monolayer increases the DOS at the Fermi level and could recover the antiferromagnetic coupling. C1 GEMME, IPCMS, F-67037 Strasbourg, France. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. RP Ostanin, S (reprint author), GEMME, IPCMS, 23 Rue Loess, F-67037 Strasbourg, France. RI Alouani, Mebarek/A-9101-2011; Uzdin, Valery/H-5622-2013 OI Alouani, Mebarek/0000-0002-7985-5276; Uzdin, Valery/0000-0002-9505-0996 NR 31 TC 33 Z9 33 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 7 BP 4870 EP 4876 DI 10.1103/PhysRevB.61.4870 PG 7 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200092 ER PT J AU Cheng, LK Sturchio, NC Bedzyk, MJ AF Cheng, LK Sturchio, NC Bedzyk, MJ TI Local structure of Co2+ incorporated at the calcite surface: An x-ray standing wave and SEXAFS study SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; SOLID-SOLUTIONS; WATER INTERFACE; BOND LENGTHS; SPECTROSCOPY; RESOLUTION; SIMULATION; ADSORPTION; SALTS; ZINC AB Following adsorption from a dilute water solution, the lattice site and first-neighbor bonding distances of Co2+ ions incorporated at the calcite (10 (1) over bar 4) surface were determined with atomic resolution by the combination of x-ray standing wave triangulation and polarization-dependent surface extended x-ray absorption fine-structure spectroscopy. The incorporated Co2+ ions selectively occupy the Ca2+ lattice sites with an inward relaxation of 0.34 Angstrom. The Co2+ ions remain octahedrally coordinated, with a first-neighbor Co-O bonding distance of 2.11 Angstrom. The octahedral coordination suggests that a coadsorbed species from the solution remains bonded to the Co2+ ion above the surface. The structure of Co2+ incorporated at the calcite surface is successfully described by a model in which the Co2+ sites are mainly determined by relaxation due to surface lattice asymmetry, and the first-neighbor Co-O relaxation by reconformation of the adjacent carbonate molecules. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Northwestern Univ, Inst Environm Catalysis, Evanston, IL 60208 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Cheng, LK (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Bedzyk, Michael/B-7503-2009; Cheng, Likwan/C-1436-2013; Bedzyk, Michael/K-6903-2013 NR 35 TC 20 Z9 20 U1 2 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 7 BP 4877 EP 4883 DI 10.1103/PhysRevB.61.4877 PG 7 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200093 ER PT J AU Cadilhe, AM Stoldt, CR Jenks, CJ Thiel, PA Evans, JW AF Cadilhe, AM Stoldt, CR Jenks, CJ Thiel, PA Evans, JW TI Evolution of far-from-equilibrium nanostructures on Ag(100) surfaces: Protrusions and indentations at extended step edges SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; CLUSTER DIFFUSION; SELF-DIFFUSION; VICINAL SI(001); ADATOM ISLANDS; METAL-SURFACES; GROWTH; DYNAMICS; ATOMS; HOMOEPITAXY AB Scanning tunneling microscopy is used to monitor the formation and relaxation of nanoprotrusions and nanoindentations at extended step edges following submonolayer deposition of Ag on Ag(100). Deposition of up to about 1/4 ML Ag produces isolated two-dimensional (2D) Ag clusters, which subsequently diffuse, collide, and coalesce with extended step edges, thus forming protrusions. Deposition of larger submonolayer amounts of Ag causes existing step edges to advance across terraces, incorporating 2D islands. The resulting irregular step structure rapidly straightens after terminating deposition, except for a few larger indentations. Relaxation of these far-from-equilibrium step-edge nanoconfigurations is monitored to determine rates for restructuring versus local geometry and feature size. This behavior is analyzed utilizing kinetic Monte Carlo simulations of an atomistic lattice-gas model for relaxation of step-edge nanostructures. In this model, mass transport is mediated by diffusion along the step edge (i.e., ''periphery diffusion''). The model consistently fits observed behavior, and allows a detailed characterization of the relaxation process, including assessment of key activation energies. C1 Iowa State Univ, IPRT, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, IPRT, Dept Math, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Cadilhe, AM (reprint author), Iowa State Univ, IPRT, Dept Chem, Ames, IA 50011 USA. RI Cadilhe, Antonio/G-1479-2016 OI Cadilhe, Antonio/0000-0002-0252-6992 NR 71 TC 22 Z9 22 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 7 BP 4910 EP 4925 DI 10.1103/PhysRevB.61.4910 PG 16 WC Physics, Condensed Matter SC Physics GA 287GB UT WOS:000085497200099 ER PT J AU Liu, R Tonjes, WC Greanya, VA Olson, CG Frindt, RF AF Liu, R Tonjes, WC Greanya, VA Olson, CG Frindt, RF TI Fermi surface of 2H-TaSe2 and its relation to the charge-density wave SO PHYSICAL REVIEW B LA English DT Article ID TRANSITION-METAL DICHALCOGENIDES; BAND STRUCTURES; LAYER COMPOUNDS; MECHANISM AB The Fermi surface (FS) of 2H-TaSe2 was investigated by high resolution angle resolved photoemission. Two FS pockets, one centered at the Gamma point and the other centered at the K point, were observed and are found to be in excellent agreement with the band calculation results. Although the FS centered at the Gamma point appears to have nested segments with the observed charge density wave (CDW) wave vectors, the CDW-induced energy gap is nearly zero on that FS. Instead, the gap opens in the extended saddle band region and on the FS centered at the K point. The implication of these results on the CDW mechanism is discussed. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Fundamental Mat Res, E Lansing, MI 48824 USA. Ames Lab, Ames, IA 50011 USA. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. RP Olson, CG (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 13 TC 37 Z9 37 U1 1 U2 12 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 FEB 15 PY 2000 VL 61 IS 8 BP 5212 EP 5216 DI 10.1103/PhysRevB.61.5212 PG 5 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000030 ER PT J AU Vitkalov, SA Bowers, CR Simmons, JA Reno, JL AF Vitkalov, SA Bowers, CR Simmons, JA Reno, JL TI ESR detection of optical dynamic nuclear polarization in GaAs/AlxGa1-xAs quantum wells at unity filling factor in the quantum Hall effect SO PHYSICAL REVIEW B LA English DT Article ID 2-DIMENSIONAL ELECTRON-GAS; LANDAU-LEVEL; GAAS-ALXGA1-XAS HETEROSTRUCTURES; PUMPED NMR; MAGNETIC-RESONANCE; GALLIUM-ARSENIDE; SPIN RESONANCE; NU=1; GAAS; EXCITATIONS AB This paper presents a study of the enhancement of the Zeeman energy of two-dimensional (2D) conduction electrons near the v=1 filling factor of the quantum Hall effect by optical dynamic nuclear polarization. The change in the Zeeman energy is determined from the Overhauser:shift of the transport detected electron spin resonance in GaAs/AlxGa1-xAs multiquantum wells. in a separate experiment the NMR signal enhancement factor is obtained by radio frequency detected nuclear magnetic resonance under similar conditions in the same sample. These measurements afford an estimation of the hyperfine coupling constant between the nuclei and 2D conduction electrons. C1 Univ Florida, Dept Chem, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Bowers, CR (reprint author), Univ Florida, Dept Chem, Gainesville, FL 32611 USA. NR 39 TC 14 Z9 14 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2000 VL 61 IS 8 BP 5447 EP 5451 DI 10.1103/PhysRevB.61.5447 PG 5 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000057 ER PT J AU Gole, JL DeVincentis, JA Seals, L Lillehei, PT Prokes, SM Dixon, DA AF Gole, JL DeVincentis, JA Seals, L Lillehei, PT Prokes, SM Dixon, DA TI Chloride salt enhancement and stabilization of the photoluminescence from a porous silicon surface SO PHYSICAL REVIEW B LA English DT Article ID ELECTROCHEMICAL METHOXYLATION; VISIBLE-PHOTOLUMINESCENCE; LUMINESCENCE MECHANISM; OPTICAL-PROPERTIES; ANODIC-OXIDATION; IN-SITU; FILMS; IDENTIFICATION; DISSOLUTION; EXCITATION AB In a postetch treatment, chloride salts are used to greatly enhance and stabilize the photoluminescence (PL) from a porous silicon (PS) surface. We compare the enhancement and stabilization induced by solutions of the strong acid HCl (H++Cl-), saturated NaCl (in MeOH, where Me denotes methyl), and a tetrabutylammonium perchlorate [TBAP(Cl-)] solution. The extent and duration of the stabilization process and its dependence on the chloride-ion concentration, the identity of the cation, and the solvent composition are outlined and contrasted to strongly quenching NaF (Na++F-) and NaOH (Na++OH-) treatments. Treatment with HCl is found to produce the most efficient enhancement of the PL signal. The H+- and Cl--ion concentrations in solution are critical as the stability of the strong HCl-induced enhancement of the nitrogen-laser-induced luminescence from the PS surface depends, as well, on the presence of methanol. PS surfaces treated in an HCl/H2O solution display a strongly enhanced in situ luminescence, which decays rapidly in an ex situ environment without treatment in ultrahigh-purity (UHP) methanol. Samples treated in an HCl(H2O)/MeOH solution (greater than 2M) maintain their enhancement for extended periods. Chloride-ion stabilization appears independent of the method of preparing the PS structure, implying that chloride salt treatment largely stabilizes the surface structure of the luminescent PS. Scanning electron micrographs demonstrate the profound change that accompanies the HCl treatment of the PS surface. Energy dispersive spectroscopy reveals chloride incorporation into the PS surface at strongly photoluminescent regions, Raman scattering demonstrates that the PL is correlated with the creation of amorphous structural regions. In conjunction with detailed quantum-chemical modeling, in which we examine the derivatization of the PS surface, time-dependent histograms obtained for the HCl-treated systems indicate that the resulting luminescence, initiated through the pumping of the HCl-modified surface, displays the manifestation of a significant surface interaction. It is suggested that this interaction might result in the formation of both chlorosilanones and chlorosilylenes, the latter of which are formed in either a photochemically induced or chloride-catalyzed conversion of the silanone, The modification of the PS surface appears to facilitate the formation of a photoluminescing "blue-green" precursor state as well as a "deep red" emitter, both of which appear to be associated, at least in part, with surface-bound silylene isomers. The importance of these results to sensor development is considered. C1 Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. USN, Res Lab, Div Elect Sci & Technol, Washington, DC 20375 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Gole, JL (reprint author), Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 57 TC 26 Z9 26 U1 2 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 FEB 15 PY 2000 VL 61 IS 8 BP 5615 EP 5631 DI 10.1103/PhysRevB.61.5615 PG 17 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000077 ER PT J AU Moodenbaugh, AR Nielsen, B Sambasivan, S Fischer, DA Friessnegg, T Aggarwal, S Ramesh, R Pfeffer, RL AF Moodenbaugh, AR Nielsen, B Sambasivan, S Fischer, DA Friessnegg, T Aggarwal, S Ramesh, R Pfeffer, RL TI Hole-state density of La1-xSrxCoO3-delta(0 <= x <= 0.5) across the insulator/metal phase boundary SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-ABSORPTION; ELECTRONIC-STRUCTURE; K-EDGE; TRANSITION; LACOO3; LA1-XSRXCOO3-DELTA; LA1-XSRXMNO3; SPECTROSCOPY; SYSTEMS; CO AB Oxygen K near-edge x-ray-absorption fine-structure (NEXAFS) of polycrystalline and film La1-xSrxCoO3-delta at room temperature was studied using fluorescence yield techniques. The bulk-sensitive nature of fluorescence yield (relative to electron yield), combined with the 0.2 eV incident photon resolution, allow us to accurately determine the evolution with x and delta of the oxygen K NEXAFS. For LaCoO3, a complex prepeak is centered near an energy E = 530.5 eV. This peak, which has a full width at half maximum of about 3.0 eV, has been identified with oxygen bonding to Co 3d electrons. With Sr substitution we observe a distinct oxygen hole peak with an intensity proportional to x, centered near E = 528.8 eV, with a full width at half maximum of 1.2 eV. In oxygen-reduced samples the hole peak tends to decrease in intensity as oxygen is removed. Comparisons are made with theoretical work and with earlier oxygen K near-edge studies on similar materials, most of which utilized electron yield. The behavior of the prepeak features with Sr (hole) doping parallels that observed in the oxide superconductors. Oxygen K NEXAFS of La0.5Sr0.5CoO3-delta thin films is compared with bulk results to estimate relative oxygen contents of the films. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. Rutgers State Univ, Serin Phys Lab, Piscataway, NJ 08854 USA. RP Moodenbaugh, AR (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Nielsen, Bent/B-7353-2009; OI Nielsen, Bent/0000-0001-7016-0040; Moodenbaugh, Arnold/0000-0002-3415-6762 NR 21 TC 41 Z9 41 U1 0 U2 15 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 FEB 15 PY 2000 VL 61 IS 8 BP 5666 EP 5671 DI 10.1103/PhysRevB.61.5666 PG 6 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000081 ER PT J AU Choi, J Borca, CN Dowben, PA Bune, A Poulsen, M Pebley, S Adenwalla, S Ducharme, S Robertson, L Fridkin, VM Palto, SP Petukhova, NN Yudin, SG AF Choi, J Borca, CN Dowben, PA Bune, A Poulsen, M Pebley, S Adenwalla, S Ducharme, S Robertson, L Fridkin, VM Palto, SP Petukhova, NN Yudin, SG TI Phase transition in the surface structure in copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%) SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; POLY(VINYLIDENE FLUORIDE); CRYSTAL-STRUCTURE; FERROELECTRIC TRANSITION; W(001) SURFACE; BAND-STRUCTURE; RECONSTRUCTION; POLYMERS; LATTICE; POLYETHYLENE AB Surface structures and a surface structure phase transition are identified that are distinct from the known bulk ferroelectric-paraelectric phase transition of crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%). The temperature-dependent changes in the surface structure are accompanied by the physical rotation of the polar group (CH2-CF2). These changes in the surface structure are compared to the bulk phase transition. We show that the bulk structural transition, while distinct from the surface, is qualitatively similar in both thick and thin Langmuir-Blodgett-grown films. C1 Univ Nebraska, Ctr Mat Res & Anal, Behlen Lab Phys, Dept Phys & Astron, Lincoln, NE 68588 USA. Oak Ridge Natl Lab, HFIR, Oak Ridge, TN 37831 USA. Russian Acad Sci, Inst Crystallog, Moscow 117333, Russia. RP Choi, J (reprint author), Univ Nebraska, Ctr Mat Res & Anal, Behlen Lab Phys, Dept Phys & Astron, Lincoln, NE 68588 USA. RI Ducharme, Stephen/A-1909-2009 OI Ducharme, Stephen/0000-0003-0936-7995 NR 57 TC 98 Z9 99 U1 0 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 FEB 15 PY 2000 VL 61 IS 8 BP 5760 EP 5770 DI 10.1103/PhysRevB.61.5760 PG 11 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000094 ER PT J AU Hamilton, JC Sorensen, MR Voter, AE AF Hamilton, JC Sorensen, MR Voter, AE TI Compact surface-cluster diffusion by concerted rotation and translation SO PHYSICAL REVIEW B LA English DT Article ID IR(111); METALS; IR AB First-principles calculations show that a pseudomorphic Ir monolayer on Lr(111) has an unexpected metastable on-top configuration only slightly above the stable fee configuration. The energy required for any translation of the monolayer parallel to the surface is small. This :opens the possibility that whole clusters can move by rotation and/or translation through configurations: with many atoms in on-top sites. One such diffusion mechanism, the ''cartwheel shuffle'' could explain otherwise mysterious long jumps and high prefactors seen in the diffusion of 19-atom Ir clusters on Ir(111). C1 Sandia Natl Labs, Livermore, CA 94550 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hamilton, JC (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 18 TC 16 Z9 16 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 FEB 15 PY 2000 VL 61 IS 8 BP R5125 EP R5128 DI 10.1103/PhysRevB.61.R5125 PG 4 WC Physics, Condensed Matter SC Physics GA 290ZD UT WOS:000085707000019 ER PT J AU Chalmers, G Schalm, K AF Chalmers, G Schalm, K TI Holographic normal ordering and multiparticle states in the AdS-CFT correspondence SO PHYSICAL REVIEW D LA English DT Article ID FIELD-THEORY CORRELATORS; LOCAL OPERATOR PRODUCTS; YANG-MILLS THEORY; DE-SITTER-SPACE; DIFFERENTIAL REGULARIZATION; GAUGE THEORIES; LIGHT-CONE; RENORMALIZATION; VECTOR; MODEL AB The general correlator of composite operators of N = 4 supersymmetric gauge field theory is divergent. We introduce a means for renormalizing these correlators by adding a boundary theory on the AdS space correcting for the divergences. Such renormalizations are not equivalent to the standard normal ordering of current algebras in two dimensions. The correlators contain contact terms that contribute to the OPE; we relate them diagrammatically to correlation functions of compound composite operators dual to multi-particle states. C1 Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. SUNY Stony Brook, Inst Theoret Phys, Stony Brook, NY 11794 USA. RP Chalmers, G (reprint author), Argonne Natl Lab, Div High Energy Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. EM chalmers@pcl9.hep.anl.gov; konrad@insti.physics.sunysb.edu NR 47 TC 17 Z9 17 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 FEB 15 PY 2000 VL 61 IS 4 AR 046001 DI 10.1103/PhysRevD.61.046001 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285HG UT WOS:000085383200047 ER PT J AU Chodos, A Cooper, F Mao, WJ Minakata, H Singh, A AF Chodos, A Cooper, F Mao, WJ Minakata, H Singh, A TI Two-dimensional model with chiral condensates and Cooper pairs having a QCD-like phase structure SO PHYSICAL REVIEW D LA English DT Article ID GROSS-NEVEU MODEL; FINITE-TEMPERATURE; COLOR SUPERCONDUCTIVITY; SYMMETRY-BREAKING; FIELD-THEORIES; 2 DIMENSIONS; DENSITY; TRANSITION; BEHAVIOR; MATTER AB We generalize our previous model to an O(N) symmetric two-dimensional model which possesses chiral symmetry breaking ([<(psi)over bar>psi] condensate) and superconducting (Cooper pair [psi psi] condensates) phases at large N. At zero temperature and density, the model can be solved analytically in the large-N limit. We perform the renormalization explicitly and obtain a closed form expression of the effective potential. There exists a renormalization group invariant parameter delta that determines which of the [<(psi)over bar>psi] (delta>0) or [psi psi] (delta<0) condensates exist in the vacuum. At finite temperatures and densities, we map out the phase structure of the model by a detailed numerical analysis of the renormalized effective potential. For delta positive and sufficiently large, the phase diagram in the mu-T (chemical potential-temperature) plane exactly mimics the features expected for QCD with two light flavors of quarks. At low temperatures there exists low-mu, chiral symmetry breaking and high-mu Cooper pair condensate regions which are separated by a first-order phase transition. At high mu, when the temperature is raised, the system undergoes a second-order phase transition from the superconducting phase to an unbroken phase in which both condensates vanish. For a range of values of delta the theory possesses a tricritical point (mu(tc), and T-tc); for mu > mu(tc) (mu < mu(tc)) the phase transition from the low temperature chiral symmetry breaking phase to unbroken phase is first order (second order). For the range of delta in which the system mimics QCD, we expect the model to be useful for the investigation of dynamical aspects of nonequilibrium phase transitions, and to provide information relevant to the study of relativistic heavy ion collisions and the dense interiors of neutron stars. C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Tokyo Metropolitan Univ, Dept Phys, Tokyo 1920397, Japan. Univ Tokyo, Inst Cosm Ray Res, Res Ctr Cosm Neutrinos, Tokyo 1888502, Japan. RP Chodos, A (reprint author), Yale Univ, Dept Phys, New Haven, CT 06520 USA. EM alan.chodos@yale.edu; cooper@schwinger.lanl.gov; maow@physics.bc.edu; minakata@phys.metro-u.ac.jp; singh@lanl.gov NR 34 TC 35 Z9 37 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 FEB 15 PY 2000 VL 61 IS 4 AR 045011 DI 10.1103/PhysRevD.61.045011 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285HG UT WOS:000085383200046 ER PT J AU Davoudiasl, H AF Davoudiasl, H TI Compton scattering at the NLC and large extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID MILLIMETER; COLLIDERS; TEV AB We study Compton scattering, gamma e --> gamma e, in the context of the recent proposal for weak scale quantum gravity (WSQG) with large extra dimensions. It is shown that, with an ultraviolet cutoff M(S)similar to 1 TeV for the effective gravity theory. the cross section for this process at the Next Linear Collider (NLC) deviates from the prediction of the standard model significantly. Our results suggest that, for typical proposed NLC energies end luminosities. WSQG can be tested in the range 4 TeV less than or similar to M(S)less than or similar to 16 TeV, making gamma e --> gamma e an important test channel. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM hooman@slac.stanford.edu NR 56 TC 16 Z9 16 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 FEB 15 PY 2000 VL 61 IS 4 AR 044018 DI 10.1103/PhysRevD.61.044018 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285HG UT WOS:000085383200034 ER PT J AU Barenblatt, GI Ingerman, EA Shvets, H Vazquez, JL AF Barenblatt, GI Ingerman, EA Shvets, H Vazquez, JL TI Very intense pulse in the groundwater flow in fissurized-porous stratum SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article AB An asymptotic solution is obtained corresponding to a very intense pulse: a sudden strong increase and fast subsequent decrease of the water level at the boundary of semi-infinite fissurized-porous stratum. This flow is of practical interest: it gives a model of a groundwater flow after a high water period or after a failure of a dam around a collector of liquid waste. It is demonstrated that the fissures have a dramatic influence on the groundwater flow, increasing the penetration depth and speed of fluid penetration into the stratum. A characteristic property of the flow in fissurized-porous stratum is the rapid breakthrough of the fluid at the first stage deeply into the stratum via a system of cracks, feeding of porous blocks by the fluid in cracks, and at a later stage feeding of advancing fluid flow in fissures by the fluid, accumulated in porous blocks. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Autonoma Madrid, Dept Matemat, E-28049 Madrid, Spain. RP Barenblatt, GI (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. RI Vazquez, Juan Luis/E-3406-2013 OI Vazquez, Juan Luis/0000-0002-9871-257X NR 8 TC 3 Z9 3 U1 0 U2 4 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 FEB 15 PY 2000 VL 97 IS 4 BP 1366 EP 1369 DI 10.1073/pnas.97.4.1366 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 285VU UT WOS:000085409600015 PM 10677469 ER PT J AU Chong, JPJ Hayashi, MK Simon, MN Xu, RM Stillman, B AF Chong, JPJ Hayashi, MK Simon, MN Xu, RM Stillman, B TI A double-hexamer archaeal minichromosome maintenance protein is an ATP-dependent DNA helicase SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID REPLICATION LICENSING SYSTEM; ORIGIN RECOGNITION COMPLEX; COMPLETE GENOME SEQUENCE; MCM PROTEINS; VIRAL ORIGIN; CELL-CYCLE; T-ANTIGEN; XENOPUS; YEAST; INITIATION AB The minichromosome maintenance (MCM) proteins are essential for DNA replication in eukaryotes. Thus far, all eukaryotes have been shown to contain six highly related MCMs that apparently function together in DNA replication. Sequencing of the entire genome of the thermophilic archaeon Methanobacterium thermo-autotrophicum has allowed us to identify only a single MCM-like gene (ORF Mt1770). This gene is most similar to MCM4 in eukaryotic cells. Here we have expressed and purified the M. thermoaototrophicum MCM protein. The purified protein forms a complex that has a molecular mass of approximate to 850 kDa, consistent with formation of a double hexamer, The protein has an ATP-independent DNA-binding activity, a DMA-stimulated ATPase activity that discriminates between single- and double-stranded DNA, and a strand-displacement (helicase) activity that can unwind up to 500 base pairs. The 3' to 5' helicase activity requires both ATP hydrolysis and a functional nucleotide-binding site. Moreover, the double hexamer form is the active helicase, It is therefore likely that an MCM complex acts as the replicative DNA helicase in eukaryotes and archaea, The simplified replication machinery in archaea may provide a simplified model for assembly of the machinery required for initiation of eukaryotic DNA replication. C1 Cold Spring Harbor Lab, Cold Spring Harbor, NY 11724 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Stillman, B (reprint author), Cold Spring Harbor Lab, 1 Bungtown Rd, Cold Spring Harbor, NY 11724 USA. RI Hayashi, Mariko/L-1187-2013; OI Chong, James/0000-0001-9447-7421; Stillman, Bruce/0000-0002-9453-4091 FU NCRR NIH HHS [P41 RR001777, P41-RR01777]; NIGMS NIH HHS [GM45436, R01 GM045436] NR 45 TC 239 Z9 243 U1 0 U2 4 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 FEB 15 PY 2000 VL 97 IS 4 BP 1530 EP 1535 DI 10.1073/pnas.030539597 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 285VU UT WOS:000085409600046 PM 10677495 ER PT J AU Wang, S Guo, M Ouyang, H Li, XL Cordon-Cardo, C Kurimasa, A Chen, DJ Fuks, Z Ling, CC Li, GC AF Wang, S Guo, M Ouyang, H Li, XL Cordon-Cardo, C Kurimasa, A Chen, DJ Fuks, Z Ling, CC Li, GC TI The catalytic subunit of DNA-dependent protein kinase selectively regulates p53-dependent apoptosis but not cell-cycle arrest SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID RADIATION-INDUCED APOPTOSIS; V(D)J RECOMBINATION; P53; DAMAGE; MICE; PHOSPHORYLATION; CHECKPOINT; DEFICIENCY; PARADIGM; ANTIGEN AB DNA damage induced by ionizing radiation (IR) activates p53, leading to the regulation of downstream pathways that control cell-cycle progression and apoptosis, However, the mechanisms for the IR-induced p53 activation and the differential activation of pathways downstream of p53 are unclear. Here we provide evidence that the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) serves as an upstream effector for p53 activation in response to IR, linking DNA damage to apoptosis, DNA-PKcs knockout (DNA-PKcs-/-) mice were exposed to whole-body IR, and the cell-cycle and apoptotic responses were examined in their thymuses. Our data show that IR induction of apoptosis and Bar expression, both mediated via p53, was significantly suppressed in the thymocytes of DNA-PKcs-/- mice. In contrast, IR-induced cell-cycle arrest and p21 expression were normal. Thus, DNA-PKcs deficiency selectively disrupts p53-dependent apoptosis but nor cell-cycle arrest. We also confirmed previous findings that p21 induction was attenuated and cell-cycle arrest was defective in the thymoctyes of whole body-irradiated Atm-/- mice, but the apoptotic response was unperturbed. Taken together, our results support a model in which the upstream effecters DNA-PKcs and Atm selectively activate p53 to differentially regulate cell-cycle and apoptotic responses. Whereas Atm selects for cell-cycle arrest but not apoptosis, DNA-PKcs selects for apoptosis but not cell-cycle arrest. C1 Mem Sloan Kettering Canc Ctr, Dept Med Phys, New York, NY 10021 USA. Mem Sloan Kettering Canc Ctr, Dept Radiat Oncol, New York, NY 10021 USA. Mem Sloan Kettering Canc Ctr, Dept Pathol, New York, NY 10021 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Li, GC (reprint author), Mem Sloan Kettering Canc Ctr, Dept Med Phys, Box 72,1275 York Ave, New York, NY 10021 USA. FU NCI NIH HHS [R01 CA056909, CA-31397, CA-56909, CA-78497, T32 CA061801] NR 39 TC 124 Z9 130 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 15 PY 2000 VL 97 IS 4 BP 1584 EP 1588 DI 10.1073/pnas.97.4.1584 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 285VU UT WOS:000085409600055 PM 10677503 ER PT J AU Garcia, AE Hummer, G AF Garcia, AE Hummer, G TI Water penetration and escape in proteins SO PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS LA English DT Article DE hydration; water pentration; protein dynamics; cytochrome c ID PANCREATIC TRYPSIN-INHIBITOR; HIGH-RESOLUTION NMR; HEART CYTOCHROME-C; HYDROGEN-EXCHANGE; AQUEOUS-SOLUTION; BOUND WATER; DISORDERED WATER; HYDRATION; DYNAMICS; ENERGY AB The kinetics of water penetration and escape in cytochrome c (cyt c) is studied by molecular dynamics (MD) simulations at various temperatures. Water molecules that penetrate the protein interior during the course of an MD simulation are identified by monitoring the number of water molecules in the first coordination shell (within 3.5 Angstrom) of each water molecule in the system. Water molecules in the interior of cyt c have 0-3 water molecules in their first hydration shell and this coordination number persists for extended periods of time. At T = 300 K we identify over 200 events in which water molecules penetrate the protein and reside inside for at least 5 picoseconds (ps) within a 1.5 nanoseconds (ns) time period. Twenty-seven (27) water molecules reside for at least 300 ps, 17 water molecules reside in the protein interior for times longer than 500 ps, and two interior water molecules do not escape; at T = 360 K one water molecule does not escape; at 430 K all water molecules exchange, Some of the internal water molecules show mean square displacements (MSD) of 1 Angstrom(2) characteristic of structural waters. Others show MSD as large as 12 Angstrom(2), suggesting that some of these water molecules occupy transient cavities and diffuse extensively within the protein. Motions of protein-bound water molecules are rotationally hindered, but show large librations. Analysis of the kinetics of water escape in terms of a survival time correlation function shows a power law behavior in time that can be interpreted in terms of a broad distribution of energy barriers, relative to kappa(B)T, for water exchange. At T = 300 K estimates of the roughness of the activation energy distribution is 4-10 kJ/mol (2-4 kappa(B)T) Activation enthalpies for water escape are 6-23 kJ/mol, The difference in activation entropies between fast exchanging (0.01 ns) and slow exchanging (0.1-1 ns) water molecules is -27 J/K/mol. Dunitz (Science 1997;264:670.) has estimated the maximum entropy loss of a water molecule due to binding to be 28 J/K/mol. Therefore, our results suggest that the entropy of interior water molecules is similar to entropy of bulk water. Published 2000 Wiley-Liss, Inc.(dagger) C1 Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Theoret Biol & Biophys Grp, T10,MS K710, Los Alamos, NM 87545 USA. EM angel@+10.lanl.gov RI Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 43 TC 149 Z9 149 U1 3 U2 25 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0887-3585 EI 1097-0134 J9 PROTEINS JI Proteins PD FEB 15 PY 2000 VL 38 IS 3 BP 261 EP 272 DI 10.1002/(SICI)1097-0134(20000215)38:3<261::AID-PROT3>3.0.CO;2-Q PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 281LB UT WOS:000085160600003 PM 10713987 ER PT J AU Nordlund, K Beck, U Metzger, TH Patel, JR AF Nordlund, K Beck, U Metzger, TH Patel, JR TI Diffuse x-ray streaks from stacking faults in Si analyzed by atomistic simulations SO APPLIED PHYSICS LETTERS LA English DT Article ID DISLOCATION LOOPS; SILICON DEFECTS; POINT-DEFECTS; SCATTERING; PHASES AB Since extrinsic stacking faults can form during postimplantation annealing of Si, understanding their properties is important for reliable control of semiconductor manufacturing processes. We demonstrate how grazing incidence x-ray scattering methods can be used as a nondestructive means for detecting extrinsic stacking faults in Si. Atomistic analysis of diffuse intensity streaks is used to determine the size of the faults, the minimum size at which the streak pattern in the scattering will be visible, and the magnitude of atomic displacements in the center of the stacking fault. (C) 2000 American Institute of Physics. [S0003-6951(00)02907-7]. C1 Univ Helsinki, Accelerator Lab, FIN-00014 Helsinki, Finland. LMU Munchen, Sekt Phys, D-80539 Munich, Germany. LMU Munchen, Ctr Nanosci, D-80539 Munich, Germany. Stanford Univ, SSRL, SLAC, Stanford, CA 94309 USA. ALS, LBL, Berkeley, CA 94720 USA. RP Nordlund, K (reprint author), Univ Helsinki, Accelerator Lab, POB 43, FIN-00014 Helsinki, Finland. RI Nordlund, Kai/L-8275-2014 OI Nordlund, Kai/0000-0001-6244-1942 NR 18 TC 16 Z9 16 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 14 PY 2000 VL 76 IS 7 BP 846 EP 848 DI 10.1063/1.125604 PG 3 WC Physics, Applied SC Physics GA 280TP UT WOS:000085120100018 ER PT J AU Lozykowski, HJ Jadwisienczak, WM Brown, I AF Lozykowski, HJ Jadwisienczak, WM Brown, I TI Photoluminescence and cathodoluminescence of GaN doped with Tb SO APPLIED PHYSICS LETTERS LA English DT Article ID LUMINESCENCE AB We report the observation of the visible cathodoluminescence and photoluminescence of Tb3+ ions implanted in GaN. The sharp characteristic emission lines corresponding to Tb3+ intra-4f(8)-shell transitions are resolved in the spectral range from 350 to 900 nm, and observed over the temperature range of 7-330 K. The luminescence shows transitions which originate in the D-5(3) and D-5(4) levels and terminated in the F-7 manifolds. The cathodoluminescence emission is only weakly temperature dependent. The results indicate that Tb-doped GaN epilayers may be suitable as a material for visible optoelectronic devices. (C) 2000 American Institute of Physics. [S0003-6951(00)03707-4]. C1 Ohio Univ, Sch Elect Engn & Comp Sci, Athens, OH 45701 USA. Ohio Univ, Condensed Matter & Surface Sci Program, Athens, OH 45701 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Nicholas Copernicus Univ, Lab Solid State Optoelect, Inst Phys, PL-87400 Torun, Poland. RP Lozykowski, HJ (reprint author), Ohio Univ, Sch Elect Engn & Comp Sci, Athens, OH 45701 USA. NR 10 TC 60 Z9 62 U1 2 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 FEB 14 PY 2000 VL 76 IS 7 BP 861 EP 863 DI 10.1063/1.125609 PG 3 WC Physics, Applied SC Physics GA 280TP UT WOS:000085120100023 ER PT J AU Collins, PG Fuhrer, MS Zettl, A AF Collins, PG Fuhrer, MS Zettl, A TI 1/f noise in carbon nanotubes SO APPLIED PHYSICS LETTERS LA English DT Article ID ROPES AB The electrical noise characteristics of single-walled carbon nanotubes have been investigated. For all three cases of individual isolated nanotubes, thin films of interconnected nanotubes, and bulk nanotube mats, anomalously large bias-dependent 1/f noise is found. The noise magnitude greatly exceeds that commonly observed in metal films, carbon resistors, or even carbon fibers with comparable resistances. A single empirical expression describes the noise for all nanotube samples, suggesting a common noise-generating mechanism proportional only to the number of nanotubes in the conductor. We consider likely sources of the fluctuations, and consequences for electronic applications of nanotubes if the excessive noise cannot be suppressed. (C) 2000 American Institute of Physics. [S0003-6951(00)02701-7]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Collins, PG (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X NR 21 TC 180 Z9 181 U1 1 U2 19 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 FEB 14 PY 2000 VL 76 IS 7 BP 894 EP 896 DI 10.1063/1.125621 PG 3 WC Physics, Applied SC Physics GA 280TP UT WOS:000085120100034 ER PT J AU Sant'Anna, MM Melo, WS Santos, ACF Shah, MB Sigaud, GM Montenegro, EC AF Sant'Anna, MM Melo, WS Santos, ACF Shah, MB Sigaud, GM Montenegro, EC TI Absolute measurements of electron capture cross sections of C3+ from atomic and molecular hydrogen SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID CHARGED IONS; COLLISIONS; VELOCITY; CARBON; HE2+-H; H-2; HE+ AB Absolute measurements of single- and double-electron-capture cross sections by C3+ projectiles on atomic and molecular hydrogen targets were performed for projectile energies between 1.0 and 3.5 MeV for the single- and 1.0 and 2.0 MeV for the double-capture processes. The sigma(H)/sigma(H2) cross section ratios were measured using an absolutely calibrated tungsten-tube furnace for the production of atomic hydrogen. The single-capture data are compared with calculations based on the boundary-corrected first Born approximation, the eikonal approximation and a semiclassical model, presenting a good overall agreement. Calculations for the double capture using an analytical expression, obtained within the independent electron approximation and based on the same semiclassical model, give a reasonable qualitative description of the data. C1 Pontificia Univ Catolica Rio de Janeiro, Dept Fis, BR-22452970 Rio De Janeiro, Brazil. Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. RP Sant'Anna, MM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. RI Sigaud, Geraldo/B-6341-2008; santos, antonio/G-2033-2010; Sant'Anna, Marcelo/B-9355-2013 OI santos, antonio/0000-0001-7402-6594; Sant'Anna, Marcelo/0000-0001-5342-5799 NR 27 TC 8 Z9 8 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 FEB 14 PY 2000 VL 33 IS 3 BP 353 EP 364 DI 10.1088/0953-4075/33/3/305 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 287AG UT WOS:000085480600007 ER PT J AU Hiess, A Boucherle, JX Givord, F Schweizer, J Lelievre-Berna, E Tasset, F Gillon, B Canfield, PC AF Hiess, A Boucherle, JX Givord, F Schweizer, J Lelievre-Berna, E Tasset, F Gillon, B Canfield, PC TI Magnetism in intermediate-valence YbAl3: a polarized neutron diffraction study SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID KONDO RESONANCE; COMPOUND YBAL3; INTERMETALLIC COMPOUNDS; CESN3; YTTERBIUM; BEHAVIOR; DENSITY AB Polarized neutron diffraction experiments on YbAl3 have revealed the following: (i) a field-induced magnetic moment on the ytterbium site only, which is well described by a Yb3+ free-ion form factor; (ii) a second maximum at T approximate to 15 K in the temperature dependence of the localized magnetic moment in addition to the well-known maximum at T = 130 K; and (iii) a small temperature-independent positive conduction electron polarization The possible microscopic origin of those observations is discussed. A comparison with the isostructural intermediate-valence compound CeSn3 reveals important differences which increase our understanding of the ground state in those compounds. C1 CEA, Dept Rech Fondamentale Mat Condensee, F-38054 Grenoble 9, France. Commiss European Communities, JRC, Inst Transuranium Elements, D-76125 Karlsruhe, Germany. Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France. CEA Saclay, Leon Brillouin Lab, F-91191 Gif Sur Yvette, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Hiess, A (reprint author), CEA, Dept Rech Fondamentale Mat Condensee, F-38054 Grenoble 9, France. RI Canfield, Paul/H-2698-2014 NR 29 TC 13 Z9 13 U1 0 U2 6 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 FEB 14 PY 2000 VL 12 IS 6 BP 829 EP 840 DI 10.1088/0953-8984/12/6/307 PG 12 WC Physics, Condensed Matter SC Physics GA 287MT UT WOS:000085510400019 ER PT J AU Soderlind, P Ross, M AF Soderlind, P Ross, M TI Rubidium at high pressure and temperature SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID CRYSTAL-STRUCTURE; X-RAY; CESIUM; METALS; STATE; IRON; GPA AB In the present paper we report theoretical calculations for the Hugoniot of shock-compressed rubidium. We use an all-electron full-potential method based on density-functional theory to obtain the total energy, pressure and electronic density of states. Thermal contributions to the equation of state (EOS) were introduced through temperature dependent occupation of the electronic states and a Gruneisen model was used for determining the nuclear thermal motion, The calculated Hugoniot is in very good agreement with the shock experiments. A temperature of about 10 000 K is reached at the pressure of about 300 kbar, the highest reached experimentally. Rubidium was chosen for this study because it undergoes a sequence of unusual pressure-induced structural transitions which have been attributed to s-d electron transfer. Since most studies of s-d transfer have been carried out at temperatures below 500 K, Little is known of how it effects the equation of state at very high temperature. We found that the predicted Rb Hugoniot is very sensitive to the thermal s-d electron transfer, which leads to a considerable lowering of the predicted Hugoniot pressure and temperature. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Soderlind, P (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 24 TC 9 Z9 9 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD FEB 14 PY 2000 VL 12 IS 6 BP 921 EP 931 PG 11 WC Physics, Condensed Matter SC Physics GA 287MT UT WOS:000085510400026 ER PT J AU Bussmann-Holder, A Buttner, H Bishop, AR AF Bussmann-Holder, A Buttner, H Bishop, AR TI Stabilization of ferroelectricity in quantum paraelectrics by isotopic substitution SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID POLARIZABILITY MODEL; TOTAL-ENERGY; ORIGIN; PHASE; PEROVSKITES; ANOMALIES; OXIDES AB SrTiO3 and KTaO3 are incipient ferroelectrics whose phase transition temperature is suppressed by quantum fluctuations. The recent observation of induced ferroelectricity due to exchange of O-16 by O-18 (1999 Phys. Rev. Lett. 82 3540) is reproduced for the dielectric data by an anharmonic electron-phonon interaction model, and a first order phase transition is predicted. Furthermore it is shown that this isotope effect does not occur in KTaO3 since its local double-well potential is much shallower than that in SrTiO3. C1 Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Univ Bayreuth, Lehrstuhl Theoret Phys 1, D-95440 Bayreuth, Germany. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Bussmann-Holder, A (reprint author), Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. NR 26 TC 44 Z9 44 U1 1 U2 12 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 FEB 14 PY 2000 VL 12 IS 6 BP L115 EP L120 DI 10.1088/0953-8984/12/6/108 PG 6 WC Physics, Condensed Matter SC Physics GA 287MT UT WOS:000085510400008 ER PT J AU Arkani-Hamed, N Dimopoulos, S Kaloper, N March-Russell, J AF Arkani-Hamed, N Dimopoulos, S Kaloper, N March-Russell, J TI Rapid asymmetric inflation and early cosmology in theories with sub-millimeter dimensions SO NUCLEAR PHYSICS B LA English DT Article ID EXTRA DIMENSIONS; COMPACTIFICATIONS; TEV AB It was recently pointed out that the fundamental Planck mass could be close to the TeV scale with the observed weakness of gravity at long distances being due the existence of new sub-millimeter spatial dimensions. In this picture the standard model fields are localized to a (3 + I)-dimensional wall or "3-brane". We show that in such theories there exist attractive models of inflation that occur while the size of the new dimensions are still small. We show that it is easy to produce the required number of efoldings, and further that the density perturbations delta rho/rho as measured by COBE can be easily reproduced, both in overall magnitude and in their approximately scale-invariant spectrum. In the minimal approach, the inflaton field is just the moduli describing the size of the internal dimensions, the role of the inflationary potential being played by the stabilizing potential of the internal space. We show that under quite general conditions, the inflationary era is followed by an epoch of contraction of our world on the brane, while the internal dimensions slowly expand to their stabilization radius. We find a set of exact solutions which describe this behavior, generalizing the well-known Kasner solutions. During this phase, the production of bulk gravitons remains suppressed. The period of contraction is terminated by the blue-shifting of Hawking radiation left on our wall at the end of the inflationary de Sitter phase. The temperature to which this is reheated is consistent with the normalcy bounds. We give a precise definition of the radion moduli problem. (C) 2000 Elsevier Science B.V. All rights resented. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Dept Phys, Stanford, CA 94309 USA. CERN, Div Theory, CH-1211 Geneva, Switzerland. RP Arkani-Hamed, N (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 51 TC 138 Z9 138 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 FEB 14 PY 2000 VL 567 IS 1-2 BP 189 EP 228 DI 10.1016/S0550-3213(99)00667-7 PG 40 WC Physics, Particles & Fields SC Physics GA 290MY UT WOS:000085681000008 ER PT J AU Gelmini, G Kusenko, A AF Gelmini, G Kusenko, A TI Unstable superheavy relic particles as a source of neutrinos responsible for ultrahigh-energy cosmic rays SO PHYSICAL REVIEW LETTERS LA English DT Article ID ZATSEPIN-KUZMIN CUTOFF; SPECTRUM; MATTER AB Decays of superheavy relic particles may produce extremely energetic neutrinos. Their annihilations on the relic neutrinos can be the origin of the cosmic rays with energies beyond the Greisrn-Zatsepin-Kuzmin cutoff. The redshift acts as a cosmological filter selecting the sources at some particular value z(e) +/- delta z, for which the present neutrino energy is close to the Z pole of the annihilation cross section. We predict no directional correlation of the ultrahigh-energy cosmic rays with the galactic halo. At the same time, there can be some directional correlations in the data, reflecting the distribution of matter at redshift z = z(e) +/- delta z. Both of these features are manifest in the existing data. Our scenario is consistent with the neutrino mass reported by super-Kamiokande and requires no lepton asymmetry or clustering of the background neutrinos. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Gelmini, G (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 38 TC 75 Z9 76 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 FEB 14 PY 2000 VL 84 IS 7 BP 1378 EP 1380 DI 10.1103/PhysRevLett.84.1378 PG 3 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100005 ER PT J AU Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Lorenc, J Pedlar, TK Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP 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 Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G 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 Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F AF Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Lorenc, J Pedlar, TK Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP 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 Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G 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 Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F CA CLEO Collaboration TI First observation of the decay B -> J/psi Phi K SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTOR AB We present the first observation of the decay B --> J/psi phi K. Using 9.6 X 10(6) B (B) over bar meson pairs collected with the CLEO detector, we have observed ten fully reconstructed B --> J/psi phi K candidates, whereas the estimated background is 0.5 +/- 0.2 event. We obtain a branching fraction of B(B --> J/psi phi K) = (8.8(-3.0)(+3.5)[stat] +/- 1.3[syst]) X 10(-5). This is the first observed B meson decay requiring the creation of an additional s (s) over bar quark pair. C1 Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 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, Ottawa, ON, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. RP Anastassov, A (reprint author), Ohio State Univ, Columbus, OH 43210 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 NR 9 TC 16 Z9 16 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 FEB 14 PY 2000 VL 84 IS 7 BP 1393 EP 1397 DI 10.1103/PhysRevLett.84.1393 PG 5 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100009 ER PT J AU Jones, MK Aniol, KA Baker, FT Berthot, J Bertin, PY Bertozzi, W Besson, A Bimbot, L Boeglin, WU Brash, EJ Brown, D Calarco, JR Cardman, LS Chang, CC Chen, JP Chudakov, E Churchwell, S Cisbani, E Dale, DS De Leo, R Deur, A Diederich, B Domingo, JJ Epstein, MB Ewell, LA Fissum, KG Fleck, A Fonvieille, H Frullani, S Gao, J Garibaldi, F Gasparian, A Gerstner, G Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Green, A Hansen, JO Howell, CR Huber, GM Iodice, M de Jager, CW Jaminion, S Jiang, X Kahl, W Kelly, JJ Khayat, M Kramer, LH Kumbartzki, G Kuss, M Lakuriki, E Lavessiere, G LeRose, JJ Liang, M Lindgren, RA Liyanage, N Lolos, GJ Macri, R Madey, R Malov, S Margaziotis, DJ Markowitz, P McCormick, K McIntyre, JI van der Meer, RLJ Michaels, R Milbrath, BD Mougey, JY Nanda, SK Offermann, EAJM Papandreou, Z Perdrisat, CF Petratos, GG Piskunov, NM Pomatsalyuk, RI Prout, DL Punjabi, V Quemener, G Ransome, RD Raue, BA Roblin, Y Roche, R Rutledge, G Rutt, PM Saha, A Saito, T Sarty, AJ Smith, TP Sorokin, P Strauch, S Suleiman, R Takahashi, K Templon, JA Todor, L Ulmer, PE Urciuoli, GM Vernin, P Vlahovic, B Voskanyan, H Wijesooriya, K Wojtsekhowski, BB Woo, RJ Xiong, F Zainea, GD Zhou, ZL AF Jones, MK Aniol, KA Baker, FT Berthot, J Bertin, PY Bertozzi, W Besson, A Bimbot, L Boeglin, WU Brash, EJ Brown, D Calarco, JR Cardman, LS Chang, CC Chen, JP Chudakov, E Churchwell, S Cisbani, E Dale, DS De Leo, R Deur, A Diederich, B Domingo, JJ Epstein, MB Ewell, LA Fissum, KG Fleck, A Fonvieille, H Frullani, S Gao, J Garibaldi, F Gasparian, A Gerstner, G Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Green, A Hansen, JO Howell, CR Huber, GM Iodice, M de Jager, CW Jaminion, S Jiang, X Kahl, W Kelly, JJ Khayat, M Kramer, LH Kumbartzki, G Kuss, M Lakuriki, E Lavessiere, G LeRose, JJ Liang, M Lindgren, RA Liyanage, N Lolos, GJ Macri, R Madey, R Malov, S Margaziotis, DJ Markowitz, P McCormick, K McIntyre, JI van der Meer, RLJ Michaels, R Milbrath, BD Mougey, JY Nanda, SK Offermann, EAJM Papandreou, Z Perdrisat, CF Petratos, GG Piskunov, NM Pomatsalyuk, RI Prout, DL Punjabi, V Quemener, G Ransome, RD Raue, BA Roblin, Y Roche, R Rutledge, G Rutt, PM Saha, A Saito, T Sarty, AJ Smith, TP Sorokin, P Strauch, S Suleiman, R Takahashi, K Templon, JA Todor, L Ulmer, PE Urciuoli, GM Vernin, P Vlahovic, B Voskanyan, H Wijesooriya, K Wojtsekhowski, BB Woo, RJ Xiong, F Zainea, GD Zhou, ZL CA Jefferson Lab Hall A Collaboration TI G(Ep)/G(Mp) ratio by polarization transfer in (e)over-right-arrowp -> e(p)over-right-arrow SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTROMAGNETIC FORM-FACTORS; LARGE-MOMENTUM-TRANSFER; QUARK-MODEL; ELECTRON-SCATTERING; NUCLEON; PROTON AB The ratio of the proton's elastic electromagnetic form factors, G(Ep)/G(Mp), was obtained by measuring P-t and P-l, the transverse and the longitudinal recoil proton polarization, respectively For elastic (e) over right arrow p --> e (p) over right arrow, G(Ep)/G(Mp) is proportional to P-t/P-l. Simultaneous measurement of P-t and P-l in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G(Ep)/G(Mp) show a systematic decrease as Q(2) increases from 0.5 to 3.5 GeV2, indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton. C1 Coll William & Mary, Williamsburg, VA 23187 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Norfolk State Univ, Norfolk, VA 23504 USA. Univ Georgia, Athens, GA 30602 USA. Univ Regina, Regina, SK S4S 0A2, Canada. Univ Blaise Pascal, CNRS, IN2P3, F-63177 Clermont Ferrand, France. Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. Duke Univ, Durham, NC 27708 USA. TUNL, Durham, NC 27708 USA. Eastern Kentucky Univ, Richmond, KY 40475 USA. Florida Int Univ, Miami, FL 33199 USA. Florida State Univ, Tallahassee, FL 32306 USA. CNRS, IN2P3, Inst Sci Nucl, F-38026 Grenoble, France. Hampton Univ, Hampton, VA 23668 USA. Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy. Univ Bari, I-70126 Bari, Italy. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Ist Super Sanita, I-00161 Rome, Italy. Joint Inst Nucl Res, LHE, Dubna 141980, Moscow Region, Russia. Kent State Univ, Kent, OH 44242 USA. Univ Kentucky, Lexington, KY 40506 USA. Kharkov Phys & Technol Inst, UA-310108 Kharkov, Ukraine. Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. Univ Maryland, College Pk, MD 20742 USA. MIT, Cambridge, MA 02139 USA. Univ New Hampshire, Durham, NH 03824 USA. N Carolina Cent Univ, Durham, NC 27707 USA. Old Dominion Univ, Norfolk, VA 23508 USA. Inst Phys Nucl, F-91406 Orsay, France. CEA Saclay, F-91191 Gif Sur Yvette, France. Syracuse Univ, Syracuse, NY 13244 USA. Temple Univ, Philadelphia, PA 19122 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Tohoku Univ, Sendai, Miyagi 980, Japan. Univ Virginia, Charlottesville, VA 22901 USA. Univ Western Cape, Cape Town, South Africa. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Jones, MK (reprint author), Coll William & Mary, Williamsburg, VA 23187 USA. RI Kuss, Michael/H-8959-2012; Sarty, Adam/G-2948-2014; McIntyre, Justin/P-1346-2014; Cisbani, Evaristo/C-9249-2011 OI McIntyre, Justin/0000-0002-3706-4310; Cisbani, Evaristo/0000-0002-6774-8473 NR 38 TC 680 Z9 684 U1 1 U2 12 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 FEB 14 PY 2000 VL 84 IS 7 BP 1398 EP 1402 DI 10.1103/PhysRevLett.84.1398 PG 5 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100010 ER PT J AU Mihaila, B Heisenberg, JH AF Mihaila, B Heisenberg, JH TI Microscopic calculation of the inclusive electron scattering structure function in O-16 SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHARGE-INDEPENDENCE BREAKING; MONTE-CARLO CALCULATIONS; GROUND-STATE; COULOMB SUM; NUCLEI; SYSTEMS; FORM AB We calculate the charge form factor and the longitudinal structure function for O-16 and compare with the available experimental data, up to a momentum transfer of 4 fm(-1). The ground-state correlations are generated using the coupled-cluster [exp(S)] method, together with the realistic v18 NN interaction and the Urbana IX three-nucleon interaction. Center-of-mass corrections are dealt with by adding a center-of-mass Hamiltonian to the usual internal Hamiltonian, and by means of a many-body expansion for the computation of the observables measured in the center-of-mass system. C1 Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Mihaila, B (reprint author), Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. RI Mihaila, Bogdan/D-8795-2013 OI Mihaila, Bogdan/0000-0002-1489-8814 NR 28 TC 31 Z9 31 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 FEB 14 PY 2000 VL 84 IS 7 BP 1403 EP 1406 DI 10.1103/PhysRevLett.84.1403 PG 4 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100011 ER PT J AU Santala, MIK Zepf, M Watts, I Beg, FN Clark, E Tatarakis, M Krushelnick, K Dangor, AE McCanny, T Spencer, I Singhal, RP Ledingham, KWD Wilks, SC Machacek, AC Wark, JS Allott, R Clarke, RJ Norreys, PA AF Santala, MIK Zepf, M Watts, I Beg, FN Clark, E Tatarakis, M Krushelnick, K Dangor, AE McCanny, T Spencer, I Singhal, RP Ledingham, KWD Wilks, SC Machacek, AC Wark, JS Allott, R Clarke, RJ Norreys, PA TI Effect of the plasma density scale length on the direction of fast electrons in relativistic laser-solid interactions SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-INTENSITY-LASER; HOT-ELECTRONS; ABSORPTION; TARGETS; LIGHT AB The angular distribution of bremsstrahlung gamma rays produced by fast electrons accelerated in relativistic laser-solid interaction has been studied by photoneutron activation in copper. We show that the gamma-ray beam moves from the target normal to the direction of the k(laser) vector as the scale length is increased. Similar behavior is found also in 2D particle-in-cell simulations. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Plasma Phys Grp, London SW7 2BZ, England. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England. RP Santala, MIK (reprint author), Helsinki Univ Technol, POB 2200, Helsinki 02015, Finland. RI Zepf, Matt/M-1232-2014 NR 23 TC 163 Z9 172 U1 0 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 14 PY 2000 VL 84 IS 7 BP 1459 EP 1462 DI 10.1103/PhysRevLett.84.1459 PG 4 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100025 ER PT J AU Mitas, L Grossman, JC Stich, I Tobik, J AF Mitas, L Grossman, JC Stich, I Tobik, J TI Silicon clusters of intermediate size: Energetics, dynamics, and thermal effects SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM MONTE-CARLO; DENSITY-FUNCTIONAL THERMOCHEMISTRY; TOTAL-ENERGY CALCULATIONS; MOLECULAR-DYNAMICS; EXACT-EXCHANGE; GEOMETRIES; SPECTRA AB A combination of the best available theoretical techniques for energetics, dynamics, and thermodynamics is employed in an extensive study of Si-n (n = 20, 25) clusters. For T = 0 we solve the electronic structure by the density functional and the highly accurate quantum Monte Carlo approaches. Finite temperature and dynamical effects are investigated by the ab initio molecular dynamics method. This combination of methods enables us to find several new low-energy isomers and to explain the differences in properties, behavior, and stability of elongated versus compact types of structures and to elucidate the origin of the existing discrepancies between theory and experiments. C1 Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Slovak Univ Technol Bratislava, Dept Phys, Bratislava 81219, Slovakia. Joint Res Ctr Atom Technol & Angstrom Technol Par, Tsukuba, Ibaraki 305, Japan. RP Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. NR 26 TC 130 Z9 132 U1 2 U2 13 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 FEB 14 PY 2000 VL 84 IS 7 BP 1479 EP 1482 DI 10.1103/PhysRevLett.84.1479 PG 4 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100030 ER PT J AU Xu, L Salmeron, M Bardon, S AF Xu, L Salmeron, M Bardon, S TI Wetting and molecular orientation of 8CB on silicon substrates SO PHYSICAL REVIEW LETTERS LA English DT Article ID POLARIZATION FORCE MICROSCOPY; LIQUID-CRYSTAL; CAPILLARY PHENOMENA; SURFACE; CONDENSATION; TRANSITION; MONOLAYERS; RESOLUTION; FILMS; WATER AB The wetting properties of 8CB (4'-n-octyl-4-cyanobiphenyl) on silicon wafers have been studied with scanning polarization force microscopy (SPFM). Layer-by-layer spreading of 8CB droplets is observed. With the help of the surface potential mapping capability of SPFM, we found that the molecular dipole of the first monolayer of 8CB is parallel to the surface. A layer of nearly Vertical molecular dimers on top of the monolayer has an associated surface potential of 40 mV, which is attributed to a distortion of the dimer. The dimer distortion propagates to the subsequent smectic bilayers, producing an additional 7 mV potential increase in the second layer, 2 mV on the third, and similar to 1 mV on the fourth. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Coll France, Phys Mat Condensee Lab, F-75231 Paris, France. RP Xu, L (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 19 TC 46 Z9 47 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 14 PY 2000 VL 84 IS 7 BP 1519 EP 1522 DI 10.1103/PhysRevLett.84.1519 PG 4 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100040 ER PT J AU Berman, GP Doolen, GD Tsifrinovich, VI AF Berman, GP Doolen, GD Tsifrinovich, VI TI Influence of superpositional wave function oscillations on Shor's quantum algorithm SO PHYSICAL REVIEW LETTERS LA English DT Article ID ERROR-CORRECTION; COMPUTATION; COMPUTER; IMPLEMENTATION AB We investigate the influence of superpositional wave function oscillations on the performance of Shor's quantum algorithm for factorization of integers. It is shown that wave function oscillations can modify the required quantum interference. This undesirable effect can be routinely eliminated using a resonant pulse implementation of quantum computation, but requires special analysis for nonresonant implementations. We also discuss the influence of this effect on implementation of other quantum algorithms. 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. Polytech Univ, IDS Dept, Brooklyn, NY 11201 USA. RP Berman, GP (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 21 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 14 PY 2000 VL 84 IS 7 BP 1615 EP 1618 DI 10.1103/PhysRevLett.84.1615 PG 4 WC Physics, Multidisciplinary SC Physics GA 283GB UT WOS:000085267100064 ER PT J AU Cairney, JM Munroe, PR Schneibel, JH AF Cairney, JM Munroe, PR Schneibel, JH TI Examination of fracture surfaces using focused ion beam milling SO SCRIPTA MATERIALIA LA English DT Article DE composites; intermetallic; fracture ID MECHANICAL-PROPERTIES; MELT INFILTRATION; COMPOSITES; FEAL; MICROSTRUCTURE C1 Univ New S Wales, Sydney, NSW 2052, Australia. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Cairney, JM (reprint author), Univ New S Wales, Sydney, NSW 2052, Australia. RI Cairney, Julie/J-7931-2012; Munroe, Paul/I-9313-2016; OI Munroe, Paul/0000-0002-5091-2513; Cairney, Julie/0000-0003-4564-2675 NR 14 TC 20 Z9 22 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD FEB 14 PY 2000 VL 42 IS 5 BP 473 EP 478 DI 10.1016/S1359-6462(99)00374-7 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 291AN UT WOS:000085710700010 ER PT J AU He, L Allard, LF Ma, E AF He, L Allard, LF Ma, E TI Fe-Cu two-phase nanocomposites: Application of a modified rule of mixtures SO SCRIPTA MATERIALIA LA English DT Article DE nanocomposites; iron-copper alloys; hardness; microstructure ID NANOCRYSTALLINE COPPER; STRENGTH; COMPOSITES; MICROSTRUCTURE; ALLOYS; MICROHARDNESS; DEFORMATION; BEHAVIOR; NB C1 Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP He, L (reprint author), Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. RI Ma, En/A-3232-2010 NR 31 TC 15 Z9 16 U1 1 U2 11 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 FEB 14 PY 2000 VL 42 IS 5 BP 517 EP 523 DI 10.1016/S1359-6462(99)00300-0 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 291AN UT WOS:000085710700017 ER PT J AU Kele, M Guiochon, G AF Kele, M Guiochon, G TI Repeatability and reproducibility of retention data and band profiles on reversed-phase liquid chromatography columns - IV. Results obtained with luna C-18 (2) columns SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article; Proceedings Paper CT 23rd International Symposium on High Performance Liquid Phase Separations and Related Techniques CY MAY 30-JUN 04, 1999 CL GRANADA, SPAIN DE band profiles; luna C-18 (2); stationary phases, LC; retention data ID PRINCIPAL COMPONENTS-ANALYSIS; BASIC COMPOUNDS; HOMOLOGOUS SERIES; STATIONARY PHASES; BEHAVIOR; SILICA AB The reproducibility of retention data and band profile characteristics was investigated for a series of columns packed with Luna C-18 (2), a silica-based, reversed-phase adsorbent. High precision data were obtained and statistically compared among five columns from the same batch (column-to-column reproducibility) and nine columns from as many different batches (batch-to-batch reproducibility). These data were acquired under five different sets of chromatographic conditions, for a group of 30 neutral, acidic, and basic compounds selected as probes following an experimental protocol previously described. This work is part of a study on the precision of chromatographic analyses. Its purpose is to illustrate the contribution of the stationary phase reproducibility to this precision. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 29 TC 62 Z9 62 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD FEB 11 PY 2000 VL 869 IS 1-2 BP 181 EP 209 DI 10.1016/S0021-9673(99)01092-4 PG 29 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 285RJ UT WOS:000085401600018 PM 10720237 ER PT J AU Volkow, ND Wang, GJ Fowler, JS Franceschi, D Thanos, PK Wong, C Gatley, SJ Ding, YS Molina, P Schlyer, D Alexoff, D Hitzemann, R Pappas, N AF Volkow, ND Wang, GJ Fowler, JS Franceschi, D Thanos, PK Wong, C Gatley, SJ Ding, YS Molina, P Schlyer, D Alexoff, D Hitzemann, R Pappas, N TI Cocaine abusers show a blunted response to alcohol intoxication in limbic brain regions SO LIFE SCIENCES LA English DT Article DE drug addiction; reward; brain glucose metabolism; positron emission tomography; neurotoxicity ID ETHANOL; METABOLISM; BENZODIAZEPINES; RAT AB Cocaine and alcohol are frequently used simultaneously and this combination is associated with enhanced toxicity. We recently showed that active:cocaine abusers have a markedly enhanced sensitivity to benzodiazepines. Because both benzodiazepines and alcohol facilitate GABAergic neurotransmission we questioned whether cocaine abusers would also have an enhanced sensitivity to alcohol that could contribute to the toxicity. In this study we compared the effects of alcohol (0.75 g/kg) on regional brain glucose metabolism between cocaine abusers (n=9) and controls (n=10) using PET and FDG. Alcohol significantly decreased whole brain metabolism and this effect was greater in controls (26+/-6%) than in abusers (17+/-10%) even though they had equivalent levels of alcohol in plasma. Analysis of the regional measures showed that cocaine abusers had a blunted response to alcohol in limbic regions, cingulate gyrus, medial frontal and orbitofrontal cortices, Conclusions: The blunted response to alcohol in cocaine abusers contrasts with their enhanced sensitivity to benzodiazepines suggesting that targets other than GABA-benzodiazepine receptors are involved in the blunted sensitivity to alcohol and that the toxicity from combined cocaine-alcohol use is not due to an enhanced sensitivity to alcohol in cocaine abusers. The blunted response to alcohol in limbic regions and in cortical regions connected to limbic areas could result from a decreased sensitivity of reward circuits in cocaine abusers. (C) 2000 Elsevier Science Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. SUNY Stony Brook, Dept Psychiat, Stony Brook, NY 11794 USA. Louisiana State Univ, Dept Physiol, New Orleans, LA 70112 USA. RP Volkow, ND (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. EM volkow@bnl.gov FU NIDA NIH HHS [DA06891] NR 24 TC 7 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0024-3205 J9 LIFE SCI JI Life Sci. PD FEB 11 PY 2000 VL 66 IS 12 BP PL161 EP PL167 DI 10.1016/S0024-3205(00)00421-5 PG 7 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA 286XP UT WOS:000085474400013 PM 10737368 ER PT J AU Revnivtsev, MG Trudolyubov, SP Borozdin, KN AF Revnivtsev, MG Trudolyubov, SP Borozdin, KN TI RXTE observations of Galactic microquasar XTE J1748-288 during its 1998 outburst SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE black hole physics; binaries : general; stars : individual : XTE J1748-288; novae, cataclysmic variables; X-rays : general ID QUASI-PERIODIC OSCILLATIONS; X-RAY SOURCES; NOVA-MUSCAE; HIGH STATE; GS-1124-683; VARIABILITY; CYGNUS-X-1; DISCOVERY; SCORPIUS; GX-339-4 AB We present an analysis of the RXTE observations of the recently discovered Galactic microquasar XTE J1748-288 during its 1998 outburst. General spectral and temporal properties of the source and their evolution were very typical for the Galactic black hole candidates (BHC) and, in particular, black hole X-ray novae. The spectral evolution of the source during the outburst can be considered a sequence of qualitatively distinct states. During the first observations, corresponding to a maximum of the X-ray flux, the spectrum of the source consisted of a dominating hard power-law component and a soft thermal component, which can be described by a model for the multicolour-disc emission. The hard component contributed greater than or equal to 80 per cent to the X-ray luminosity in the 3-25 keV energy band. Overall the two-component spectral shape is an attribute of the very high state observed previously in BHC, but the domination of the hard component is unusual. Later on, as the X-ray source faded, its energy spectrum qualitatively changed, showing high and then low states, both typical for black hole binaries. As the energy spectrum changed, the fast variability also evolved dramatically. Initially the power-density spectrum was formed by a dominating band-limited noise component, quasi periodical oscillation features at 20-30 Hz and at similar to 0.5 Hz, and a very low-frequency noise component. After a significant decrease of the contribution of the hard spectral component, the amplitude of the fractional variability decreased by an order of magnitude and the power-density spectrum adopted a power-law shape with a broad quasi periodical oscillation peak around 0.03 Hz. When the system switched to the low state, the power-density spectrum shape changed again and the quasi periodical oscillations have not been detected since. When the source was observed in the very high state, a clear correlation between quasi periodical oscillation parameters and X-ray flux was seen. Such a correlation gives an insight into our understanding of the accretion process in X-ray black hole binaries. 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, MG (reprint author), Russian Acad Sci, Space Res Inst, Profsoyuznaya 84-32, Moscow 117810, Russia. NR 42 TC 47 Z9 47 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 11 PY 2000 VL 312 IS 1 BP 151 EP 158 DI 10.1046/j.1365-8711.2000.03144.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 289RA UT WOS:000085634700016 ER PT J AU Huffman, PR Brome, CR Butterworth, JS Coakley, KJ Dewey, MS Dzhosyuk, SN Gilliam, DM Golub, R Greene, GL Habicht, K Lamoreaux, SK Mattoni, CEH McKinsey, DN Wietfeldt, FE Doyle, JM AF Huffman, PR Brome, CR Butterworth, JS Coakley, KJ Dewey, MS Dzhosyuk, SN Gilliam, DM Golub, R Greene, GL Habicht, K Lamoreaux, SK Mattoni, CEH McKinsey, DN Wietfeldt, FE Doyle, JM TI Progress towards magnetic trapping of ultra-cold neutrons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN DE beta decay; extreme ultraviolet; liquid helium; magnetic trap; neutron lifetime; scintillation; superthermal; ultra-cold neutrons; weak force ID SUPERFLUID HE-4; LIFETIME; STORAGE; SCATTERING; HELIUM AB We report progress towards magnetic trapping: of ultra-cold neutrons (UCN) in preparation for a neutron lifetime measurement. UCN will be produced by inelastic scattering of cold (0.89 nm) neutrons in a reservoir of superfluid He-4 and confined in a three-dimensional magnetic trap. As the trapped neutrons decay, recoil electrons will generate scintillations in the liquid He, which should be detectable with nearly 100% efficiency. This direct measure of the number of UCN decays vs, time can be used to determine the neutron beta-decay lifetime. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIST, Gaithersburg, MD 20899 USA. Harvard Univ, Cambridge, MA 02138 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, D-1000 Berlin, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Huffman, PR (reprint author), NIST, Gaithersburg, MD 20899 USA. RI Habicht, Klaus/K-3636-2013; OI Habicht, Klaus/0000-0002-9915-7221; Huffman, Paul/0000-0002-2562-1378 NR 27 TC 4 Z9 4 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 FEB 11 PY 2000 VL 440 IS 3 BP 522 EP 527 DI 10.1016/S0168-9002(99)01030-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900010 ER PT J AU Snow, WM Chowdhuri, Z Dewey, MS Fei, X Gilliam, DM Greene, GL Nico, JS Wietfeldt, FE AF Snow, WM Chowdhuri, Z Dewey, MS Fei, X Gilliam, DM Greene, GL Nico, JS Wietfeldt, FE TI A measurement of the neutron lifetime by counting trapped protons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN DE neutron decay; Penning trap ID B-10; FLUX AB A measurement of the neutron lifetime tau(n) performed by trapping and counting decay protons from in-beam neutron decays in a Penning trap is in progress at the National Institute of Standards and Technology (NIST). A description of the measurement technique, the status of the data analysis, and prospects for improvements in the measurement are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Snow, WM (reprint author), Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. NR 17 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 528 EP 534 DI 10.1016/S0168-9002(99)01031-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900011 ER PT J AU Fischer, P Ioffe, A Jacobson, DL Arif, M Mezei, F AF Fischer, P Ioffe, A Jacobson, DL Arif, M Mezei, F TI 4 pi-Periodicity of the spinor wave function under space rotation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN ID NEUTRON; PHASE; PRECESSION AB We report the results of an experiment which observed the 4 pi-symmetry of the neutron wave function under space rotation by the use of a slowly rotating magnetic field which trapped the precessing neutron spin and turned it in space. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, Berlin Neutron Scattering Ctr, D-14109 Berlin, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ioffe, A (reprint author), Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 575 EP 578 DI 10.1016/S0168-9002(99)01039-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900019 ER PT J AU Jones, GL Adams, JM Anaya, JM Bowles, TJ Chupp, TE Coulter, KP Dewey, MS Freedman, SJ Fujikawa, BK Garcia, A Greene, GL Hwang, SR Lising, LJ Mumm, HP Nico, JS Robertson, RGH Steiger, TD Teasdale, WA Thompson, AK Wasserman, EG Wietfeldt, FE Wilkerson, JF AF Jones, GL Adams, JM Anaya, JM Bowles, TJ Chupp, TE Coulter, KP Dewey, MS Freedman, SJ Fujikawa, BK Garcia, A Greene, GL Hwang, SR Lising, LJ Mumm, HP Nico, JS Robertson, RGH Steiger, TD Teasdale, WA Thompson, AK Wasserman, EG Wietfeldt, FE Wilkerson, JF TI Time reversal in polarized neutron decay: the emiT experiment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN DE neutron beta decay; angular correlation; weak interaction ID LEFT-RIGHT-SYMMETRY AB The standard electro-weak model predicts negligible violation of time-reversal invariance in light quark processes. We report on an experimental test of time-reversal invariance in the beta decay of polarized neutrons as a search for physics beyond the standard model. The emiT collaboration has measured the time-reversal-violating triple-correlation in neutron beta decay between the neutron spin, electron momentum, and neutrino momentum often referred to as the D coefficient. The first run of the experiment produced 14 million events which are currently being analyzed. However, a second run with improved detectors should provide greater statistical precision and reduced systematic uncertainties. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Univ Washington, Seattle, WA 98195 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Jones, GL (reprint author), Hamilton Coll, Clinton, NY 13323 USA. OI Universidad del Rosario, Biblioteca/0000-0003-3491-9392; Wilkerson, John/0000-0002-0342-0217; Anaya, Juan-Manuel/0000-0002-6444-1249; Garcia, Alejandro/0000-0001-6056-6645 NR 13 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 648 EP 652 DI 10.1016/S0168-9002(99)01056-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900031 ER PT J AU Serebrov, A Mityukhlyaev, V Zakharov, A Kharitonov, A Shustov, V Kuz'minov, V Lasakov, M Tal'daev, R Aldushchenkov, A Varlamov, V Vasil'ev, A Sazhin, M Greene, G Bowles, T Hill, R Seestrom, S Geltenbort, P AF Serebrov, A Mityukhlyaev, V Zakharov, A Kharitonov, A Shustov, V Kuz'minov, V Lasakov, M Tal'daev, R Aldushchenkov, A Varlamov, V Vasil'ev, A Sazhin, M Greene, G Bowles, T Hill, R Seestrom, S Geltenbort, P TI Studies of a solid-deuterium source for ultra-cold neutrons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN AB The results of experiments and calculations for a solid-deuterium UCN source are presented. It was experimentally shown that the UCN yield is increased by a factor 3 at the solidification of liquid deuterium and a factor 10 at a temperature 10 K, with respect to the liquid phase. The gain factor for UCN yield with respect to hydrogen gas or deuterium gas at room temperature is equal to 1230. (C) 2000 Elsevier Science B.V. FLU rights reserved. C1 Russian Acad Sci, St Petersburg Nucl Phys Inst, Gatchina 188350, Leningrad Dist, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Serebrov, A (reprint author), Russian Acad Sci, St Petersburg Nucl Phys Inst, Gatchina 188350, Leningrad Dist, Russia. RI Mityukhlyaev, Vitaly/B-2824-2014; Serebrov, Anatoly/A-6771-2014 OI Serebrov, Anatoly/0000-0002-6734-038X NR 8 TC 32 Z9 33 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 658 EP 665 DI 10.1016/S0168-9002(99)01058-X PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900033 ER PT J AU Hill, RE Anaya, JM Bowles, TJ Greene, GL Hogan, G Lamoreaux, S Marek, L Mortenson, R Morris, CL Saunders, A Seestrom, SJ Teasdale, W Hoedl, S Liu, CY Smith, DA Young, A Filippone, BW Hua, J Ito, T Pasyuk, E Geltenbort, P Garcia, A Fujikawa, B Baessler, S Serebrov, A AF Hill, RE Anaya, JM Bowles, TJ Greene, GL Hogan, G Lamoreaux, S Marek, L Mortenson, R Morris, CL Saunders, A Seestrom, SJ Teasdale, W Hoedl, S Liu, CY Smith, DA Young, A Filippone, BW Hua, J Ito, T Pasyuk, E Geltenbort, P Garcia, A Fujikawa, B Baessler, S Serebrov, A TI Performance of the prototype LANL solid deuterium ultra-cold neutron source SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN AB A prototype of a solid deuterium (SD2) source of Ultra-Cold Neutrons (UCN) is currently being tested at LANSCE. The source is contained within an assembly consisting of a 4 K polyethylene moderator surrounded by a 77 K beryllium flux trap in which is embedded a spallation target. Time-of-flight measurements have been made of the cold neutron spectrum emerging directly from the flux trap assembly. A comparison is presented of these measurements with results of Monte Carlo (LAHET/MCNP) calculations of the cold neutron fluxes produced in the prototype assembly by a beam of 800 MeV protons incident on the tungsten target. A UCN detector was coupled to the assembly through a guide system with a critical velocity of 8 m/s (Ni-58). The rates and time-of-flight data from this detector art: compared with calculated values. Measurements of UCN production as a function of SD. volume (thickness) are compared with predicted values. The dependence of UCN production on SD, temperature and proton beam intensity are also presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Princeton Univ, Princeton, NJ 08544 USA. CALTECH, Pasadena, CA 91125 USA. Joint Inst Nucl Res Dubna, Dubna, Russia. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Univ Notre Dame, Notre Dame, IN 46556 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Washington, Seattle, WA 98195 USA. Petersburg Nucl Phys Inst, St Petersburg, Russia. RP Hill, RE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Yuan, Junhua/C-7923-2009; Serebrov, Anatoly/A-6771-2014; OI Serebrov, Anatoly/0000-0002-6734-038X; Garcia, Alejandro/0000-0001-6056-6645 NR 3 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 674 EP 681 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900035 ER PT J AU Serebrov, A Vasiliev, A Lasakov, M Rudnev, Y Krasnoshekova, I Geltenbort, P Butterworth, J Bowles, T Morris, C Seestrom, S Smith, D Young, AR AF Serebrov, A Vasiliev, A Lasakov, M Rudnev, Y Krasnoshekova, I Geltenbort, P Butterworth, J Bowles, T Morris, C Seestrom, S Smith, D Young, AR TI Depolarization of UCN stored in material traps SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN DE depolarization; ultra-cold neutrons; storage AB Depolarization of ultra-cold neutrons (UCN) stored in material traps was first observed. The probability of UCN spin flip per reflection depends on the trap material and varies from 7 x 10(-6) (beryllium) to 10(-4)(glass). (C) 2000 Elsevier Science B.V. Ail rights reserved. C1 Russian Acad Sci, Petersburg Inst Nucl Phys, Gatchina 188350, Leningrad Dist, Russia. Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Princeton Univ, Princeton, NJ 08544 USA. RP Serebrov, A (reprint author), Russian Acad Sci, Petersburg Inst Nucl Phys, Gatchina 188350, Leningrad Dist, Russia. RI Serebrov, Anatoly/A-6771-2014 OI Serebrov, Anatoly/0000-0002-6734-038X NR 6 TC 10 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 717 EP 721 DI 10.1016/S0168-9002(99)01068-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900042 ER PT J AU Snow, WM Bazhenov, A Blessinger, CS Bowman, JD Chupp, TE Coulter, KP Freedman, SJ Fujikawa, BK Gentile, TR Greene, GL Hansen, G Hogan, GE Ishimoto, S Jones, GL Knudson, JN Kolomenski, E Lamoreaux, SK Leuschner, MB Masaike, A Masuda, Y Matsuda, Y Morgan, GL Morimoto, K Morris, CL Nann, H Penttila, SI Pirozhkov, A Pomeroy, VR Rich, DR Serebrov, A Sharapov, EI Smith, DA Smith, TB Welsh, RC Wietfeld, FE Wilburn, WS Yuan, VW Zerger, J AF Snow, WM Bazhenov, A Blessinger, CS Bowman, JD Chupp, TE Coulter, KP Freedman, SJ Fujikawa, BK Gentile, TR Greene, GL Hansen, G Hogan, GE Ishimoto, S Jones, GL Knudson, JN Kolomenski, E Lamoreaux, SK Leuschner, MB Masaike, A Masuda, Y Matsuda, Y Morgan, GL Morimoto, K Morris, CL Nann, H Penttila, SI Pirozhkov, A Pomeroy, VR Rich, DR Serebrov, A Sharapov, EI Smith, DA Smith, TB Welsh, RC Wietfeld, FE Wilburn, WS Yuan, VW Zerger, J TI Measurement of the parity violating asymmetry A(gamma) in (n)over-right-arrow+p -> d+gamma SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT International Workshop on Particle Physics with Slow Neutrons CY OCT 22-24, 1998 CL INST LAUE LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin, City Grenoble, Neutrons Sci HO INST LAUE LANGEVIN DE neutral current; parity violation; neutron-proton capture; deuteron; weak pion-nucleon coupling ID PION-NUCLEON COUPLINGS; ANAPOLE MOMENT; COLLISIONS AB The weak interaction between neutrons and protons has never been resolved experimentally. In analogy with the strong NN interaction, the weak NN interaction at low energy can be parametrized in terms of a meson exchange model with parity violating meson-nucleon couplings. Unlike the measured proton-proton weak interaction, the neutron-proton weak interaction is sensitive to the weak pion-nucleon coupling constant H-pi(1). This coupling, which is responsible for the longest-ranged part of the weak NN interaction and is therefore an essential part of any description of weak interactions in nuclei, remains undetermined despite many years of effort. A measurement of the gamma ray directional asymmetry A(gamma) in the capture of polarized neutrons by parahydrogen has been proposed at Los Alamos National Laboratory. The goal of this experiment is to determine A(gamma) with a relative standard uncertainty of < 5 x 10(-9), which is smaller than all modern predictions for the size of the asymmetry. The design of the experiment is presented, with an emphasis on the techniques used for controlling systematic errors. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. Petersburg Nucl Phys Inst, Petersburg, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NIST, Gaithersburg, MD 20899 USA. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Kyoto Univ, Dept Phys, Kyoto 606, Japan. Joint Inst Nucl Res, Dubna, Russia. RP Snow, WM (reprint author), Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. RI Matsuda, Yasuyuki/C-3007-2008; Serebrov, Anatoly/A-6771-2014 OI Matsuda, Yasuyuki/0000-0002-9847-3791; Serebrov, Anatoly/0000-0002-6734-038X NR 22 TC 55 Z9 55 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 2000 VL 440 IS 3 BP 729 EP 735 DI 10.1016/S0168-9002(99)01071-2 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 282ZD UT WOS:000085250900044 ER PT J AU Klimov, VI Mikhailovsky, AA McBranch, DW Leatherdale, CA Bawendi, MG AF Klimov, VI Mikhailovsky, AA McBranch, DW Leatherdale, CA Bawendi, MG TI Quantization of multiparticle Auger rates in semiconductor quantum dots SO SCIENCE LA English DT Article ID NANOCRYSTALS; SPECTRUM AB We have resolved single-exponential relaxation dynamics of the 2-, 3-, and 4-electron-hole pair states in nearly monodisperse cadmium selenide quantum dots with radii ranging from 1 to 4 nanometers. Comparison of the discrete relaxation constants measured for different multiple-pair states indicates that the carrier decay rate is cubic in carrier concentration, which is characteristic of an Auger process. We observe that in the quantum-confined regime, the. Auger constant is strongly size-dependent and decreases with decreasing the quantum dot size as the radius cubed. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. MIT, Dept Chem, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RP Klimov, VI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST 6,MS J585, Los Alamos, NM 87545 USA. NR 16 TC 787 Z9 797 U1 18 U2 205 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD FEB 11 PY 2000 VL 287 IS 5455 BP 1011 EP 1013 DI 10.1126/science.287.5455.1011 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 282WU UT WOS:000085245400038 ER PT J AU Scholl, A Stohr, J Luning, J Seo, JW Fompeyrine, J Siegwart, H Locquet, JP Nolting, F Anders, S Fullerton, EE Scheinfein, MR Padmore, HA AF Scholl, A Stohr, J Luning, J Seo, JW Fompeyrine, J Siegwart, H Locquet, JP Nolting, F Anders, S Fullerton, EE Scheinfein, MR Padmore, HA TI Observation of antiferromagnetic domains in epitaxial thin films SO SCIENCE LA English DT Article ID MAGNETIC DICHROISM; X-RAY; TEMPERATURE; MOMENTS AB Antiferromagnetic domains in an epitaxial thin film, LaFeO3 on SrTiO3(100), were observed using a high-spatial-resolution photoelectron emission microscope with contrast generated by the large x-ray magnetic Linear dichroism effect at the multiplet-split L edge of Fe. The antiferromagnetic domains are linked to 90 degrees twinned crystallographic regions in the film. The Neel temperature of the thin film is reduced by 70 kelvin relative to the bulk material, and this reduction is attributed to epitaxial strain. These studies open the door for a microscopic understanding of the magnetic coupling across antiferromagnetic-ferromagnetic interfaces. C1 Univ Calif Berkeley, Adv Light Source, Berkeley, CA 94720 USA. IBM Corp, Almaden Res Ctr, Div Res, San Jose, CA 95120 USA. IBM Corp, Div Res, Zurich Res Lab, CH-8803 Ruschlikon, Switzerland. Univ Neuchatel, Inst Phys, CH-2000 Neuchatel, Switzerland. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. RP Scholl, A (reprint author), Univ Calif Berkeley, Adv Light Source, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Fullerton, Eric/H-8445-2013; Seo, Jin Won/J-3980-2013; Scholl, Andreas/K-4876-2012; Raoux, Simone/G-3920-2016 OI Fullerton, Eric/0000-0002-4725-9509; Seo, Jin Won/0000-0003-4937-0769; NR 23 TC 198 Z9 199 U1 7 U2 81 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD FEB 11 PY 2000 VL 287 IS 5455 BP 1014 EP 1016 DI 10.1126/science.287.5455.1014 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 282WU UT WOS:000085245400039 ER PT J AU Fuehrer, PL Friehe, CA Hristov, TS Cooper, DI Eichinger, WE AF Fuehrer, PL Friehe, CA Hristov, TS Cooper, DI Eichinger, WE TI Statistical-uncertainty-based adaptive filtering of lidar signals SO APPLIED OPTICS LA English DT Article ID ATMOSPHERIC BOUNDARY-LAYER; LOG POWER ESTIMATION; WATER RAMAN-LIDAR; RETURN POWER AB An adaptive filter signal processing technique is developed to overcome the problem of Raman lidar water-vapor mixing ratio (the ratio of the water-vapor density to the dry-air density) with a highly variable statistical uncertainty that increases with decreasing photomultiplier-tube signal strength and masks the true desired water-vapor structure. The technique, applied to horizontal scans, assumes only statistical horizontal homogeneity. The result is a variable spatial resolution water-vapor signal with a constant variance out to a range limit set by a specified signal-to-noise ratio. The technique was applied to Raman water-vapor lidar data obtained at a coastal pier site together with in situ instruments located 320 m from the lidar. The micrometeorological humidity data were used to calibrate the ratio of the lidar gains of the H2O and the N-2 photomultiplier tubes and set the water-vapor mixing ratio variance for the adaptive filter. For the coastal experiment the! effective limit of the lidar range was found to be approximately 200 m for a maximum noise-to-signal variance ratio of 0.1 with the implemented data-reduction procedure. The technique can be adapted to off-horizontal scans with a small reduction in the constraints and is also applicable to other remote-sensing devices that exhibit the same inherent range-dependent signal-to-noise ratio problem. (C) 2000 Optical Society of America. C1 Univ Calif Irvine, Dept Mech & Aerosp Engn, Irvine, CA 92697 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Iowa, Dept Civil & Environm Engn, Iowa City, IA 52242 USA. RP Univ Calif Irvine, Dept Mech & Aerosp Engn, Irvine, CA 92697 USA. EM perry@wave.eng.uci.edu NR 7 TC 0 Z9 0 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 FEB 10 PY 2000 VL 39 IS 5 BP 850 EP 859 DI 10.1364/AO.39.000850 PG 10 WC Optics SC Optics GA 284EU UT WOS:000085318400023 PM 18337962 ER PT J AU Haiman, Z Knox, L AF Haiman, Z Knox, L TI Correlations in the far-infrared background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; diffuse radiation; cosmology : theory; cosmology : observations; galaxies : evolution; galaxies : formation ID DUST; GALAXY; COBE AB We compute the expected angular power spectrum of the cosmic far infrared background (FIRB). We find that the signal due to source correlations dominates the shot noise for l less than or similar to 1000 and results in anisotropies with rms amplitudes [l(l + 1)C-l/2 pi](1/2) between 5% and 10% of the mean for l greater than or similar to 150. The angular power spectrum depends on several unknown quantities, such as the UV flux density evolution, optical properties of the dust, biasing of the sources of the FIRE, and cosmological parameters. However, when we require our models to reproduce the observed direct current level of the FIRE, we find that the anisotropy is at least a few percent in all cases. This anisotropy is detectable with proposed instruments, and its measurement will provide strong constraints on models of galaxy evolution and large-scale structure at redshifts up to at least z similar to 5. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Haiman, Z (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. NR 54 TC 45 Z9 45 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 FEB 10 PY 2000 VL 530 IS 1 BP 124 EP 132 DI 10.1086/308374 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 290YC UT WOS:000085704600009 ER PT J AU Brickhouse, NS Dupree, AK Edgar, RJ Liedahl, DA Drake, SA White, NE Singh, KP AF Brickhouse, NS Dupree, AK Edgar, RJ Liedahl, DA Drake, SA White, NE Singh, KP TI Coronal structure and abundances of Capella from simultaneous EUVE and ASCA spectroscopy SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; stars : abundances; stars : coronae; stars : individual (Capella); ultraviolet : stars; X-rays : stars ID X-RAY-EMISSION; CANUM-VENATICORUM BINARIES; EXTREME-ULTRAVIOLET OBSERVATIONS; CHROMOSPHERICALLY ACTIVE STARS; LOCAL INTERSTELLAR-MEDIUM; K-TYPE STARS; LINE EMISSION; COOL STARS; AR-LACERTAE; OUTER ATMOSPHERES AB We report analysis of the simultaneous 1996 March EUVE and ASCA observations of the spectroscopic binary Capella. The EUVE spectrum is dominated by lines of highly ionized Fe, requiring a continuous emission-measure distribution over a wide range of temperatures. The ASCA spectrum shows He-like line emission features of S, Si, and Mg, as well as unresolved L-shell emission lines of Fe and Ni and H-like and He-like Ne lines. The flux in these line features cannot be determined independently from the continuum flux. The ASCA spectrum is relatively soft, with few counts above 4 keV. The emission-measure distribution determined by Line-Based Analysis of the EUV Fe line intensities is well constrained from T(e)similar to 6 x 10(5) to 2 x 10(7) K, but it is not constrained above this range since Fe XXIV is the highest temperature line observed with EUVE. Since repeated observations of Capella by EUVE have shown that emission-line intensities of the hottest EUV-emitting material (Fe XXI to XXIV) vary by factors up to 4, the ASCA spectrum is important for extending the temperature coverage. Thus, the high-energy cut-off of the ASCA spectrum provides a constraint on the highest temperature emission measures. In principle, elemental abundances are determined from global fits to the ASCA spectrum; however, no well-fitting model has been found for the high signal-to-noise ASCA performance verification spectrum of Capella (1993 September 2). The newer ASCA spectrum of Capella (1996 March 3-4) shows a similar pattern of fitting difficulties. Using the EUVE measurements (1996 March 3-7) to constrain models, we have conducted sensitivity studies of the atomic data, source physics, and instrument calibration. The plasma spectral emission models (Raymond-Smith, MEKAL, SPEX) around 1.2 keV appear to have flux deficits relative to the observed ASCA count spectrum. New atomic models by Liedahl and Brickhouse, calculated with the HULLAC code, provide a set of lines-missing from the existing plasma codes-to fill in this flux deficit. Incorporating these additional lines dramatically improves the spectral model fits to the data, allowing reliable determination of elemental abundances. The successful application of the new atomic models to the Capella problem can have widespread implications, affecting spectral models of galaxies, cluster cooling flows, and supernova remnants, as well as other stellar coronae. Analysis with the new atomic models of the simultaneous ASCA and EUVE data confirms the previous EUVE results that the continuous emission-measure distribution of Capella has a strong enhancement at T(e)similar to 6 x 10(6) K. While a two-temperature model actually provides a better fit to the ASCA spectrum than the EUVE-derived continuous model, the EUVE data are not well fitted with only two temperatures. We find that the abundances of Mg, Si, S, and Fe are consistent with solar photospheric values, while Ne appears to be underabundant by a factor of similar to 3 to 4. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Tata Inst Fundamental Res, Dept Astron & Astrophys, Bombay 400005, Maharashtra, India. RP Brickhouse, NS (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. RI White, Nicholas/B-6428-2012; OI White, Nicholas/0000-0003-3853-3462; Brickhouse, Nancy/0000-0002-8704-4473 NR 74 TC 85 Z9 86 U1 0 U2 6 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 FEB 10 PY 2000 VL 530 IS 1 BP 387 EP 402 DI 10.1086/308350 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 290YC UT WOS:000085704600034 ER PT J AU Liu, WH Schultz, DR AF Liu, WH Schultz, DR TI Ultraviolet emission from oxygen precipitating into Jovian aurora SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; molecular processes; planets and satellites : individual (Jupiter); ultraviolet : solar system ID ELECTRON-ELECTRON INTERACTION; HUBBLE-SPACE-TELESCOPE; CROSS-SECTIONS; JUPITER AURORA; CAPTURE; COLLISIONS; IONS; IONIZATION; HE; SPECTROSCOPY AB The ultraviolet emission-line spectra of precipitating oxygen atoms and ions excited by charge transfer interaction with the molecular hydrogen in the auroral atmosphere of Jupiter are calculated using our computed cross sections of state-selective charge transfer. The charge transfer processes preferentially populate the ground states of neutral oxygen and low-charge ions and the highly excited states of high-charge ions, yielding low UV and high X-ray efficiencies, respectively. Much weaker than the underlying emission spectrum of H-2 excited by energetic electron precipitation, the UV emission from oxygen is not expected to be discernible in the Jovian auroral spectrum. This reconciles the absence of UV emission with the presence of X-ray emission from the heavy ions precipitating in the Jovian aurora. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Liu, WH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 32 TC 22 Z9 23 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 FEB 10 PY 2000 VL 530 IS 1 BP 500 EP 503 DI 10.1086/308367 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 290YC UT WOS:000085704600044 ER PT J AU Adzic, RR Wang, JX AF Adzic, RR Wang, JX TI Structure of active phases during the course of electrocatalytic reactions SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID SURFACE-CATALYZED REACTION; O-2 REDUCTION; AU(111) AB Structures of ordered adsorbates have been determined during the course of the electrocatalytic reduction of oxygen by using synchrotron surface X-ray scattering techniques. The origin of the catalytic action of Tl adlayers on O-2 reduction on Au has been determined, and a possibility of measuring the adsorption configuration-specific activity in O-2 reduction has been demonstrated in the reaction on Ag(100) with Br adlayer. On the Au(111) electrode surface, the oxidation/redeposition of T1 in catalyzing the four-electron oxygen reduction is revealed from the analysis of X-ray diffraction intensity as a function of the O-2 reduction current for the (3 x root 3)-2TlBr adlayer. This indicates that the redox property of the metal adsorbates is responsible for the catalytic effect. On Ag(100) with the c(2 x 2) Br adlayer, the O-2 reduction current resulting solely from adsorption in the "end-on" configuration through the 4-fold symmetry holes in the c(2 x 2) Br lattice is observed, showing that the "bridge" adsorption may not be necessary for the four-electron O-2 reduction on Ag at large overpotentials. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. RP Adzic, RR (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. RI Wang, Jia/B-6346-2011 NR 12 TC 9 Z9 9 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 FEB 10 PY 2000 VL 104 IS 5 BP 869 EP 872 DI 10.1021/jp9917446 PG 4 WC Chemistry, Physical SC Chemistry GA 281PN UT WOS:000085170000001 ER PT J AU Lewis, JP Sewell, TD Evans, RB Voth, GA AF Lewis, JP Sewell, TD Evans, RB Voth, GA TI Electronic structure calculation of the structures and energies of the three pure polymorphic forms of crystalline HMX SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID N-N BOND; BRILLOUIN-ZONE; SPECIAL POINTS; AB-INITIO; PSEUDOPOTENTIALS; SYSTEMS AB The molecular structures and energetic stabilities of the three pure polymorphic forms of crystalline HMX were calculated using a first-principles electronic-structure method. The computations were performed using the local density approximation in conjunction with localized "fireball" orbitals and a minimal basis set. Optimized cell parameters and molecular geometries were obtained, subject only to preservation of the experimental lattice angles and relative lattice lengths. The latter constraint was removed in some calculations for beta-HMX. Within these constraints, the comparison between theory and experiment is found to be good. The structures, relative energies of the polymorphs, and bulk moduli are in general agreement with the available experimental data. C1 Univ Utah, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Lewis, JP (reprint author), Univ Utah, Henry Eyring Ctr Theoret Chem, 315 S 1400 E RM Dock, Salt Lake City, UT 84112 USA. NR 26 TC 47 Z9 50 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD FEB 10 PY 2000 VL 104 IS 5 BP 1009 EP 1013 DI 10.1021/jp9926037 PG 5 WC Chemistry, Physical SC Chemistry GA 281PN UT WOS:000085170000020 ER PT J AU Truhlar, DG Garrett, BC AF Truhlar, DG Garrett, BC TI Multidimensional transition state theory and the validity of Grote-Hynes theory SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID EQUILIBRIUM SOLVATION DYNAMICS; ACTIVATED CHEMICAL-REACTIONS; POLAR-SOLVENTS; MODEL AB The Grote-Hynes theory of nonequilibrium solvation effects on reaction kinetics is examined using the perspective provided by multidimensional transition state theory. The analysis is performed for a model in which a solute reaction coordinate is bilinearly coupled to a harmonic solvent bath, and we derive intermediate quantities that shed light on the ability of Grote-Hynes theory to capture relevant physical features of the reaction dynamics. One example is a separatrix distribution, in particular, the distribution P(r) of Values of the solute reaction coordinate on the variationally optimized transition state dividing surface for the multidimensional model. Another example is the reactive probability density dp/dP(B) on a trial transition state dividing surface orthogonal to the solute reaction coordinate. The model is seen to be capable of producing wide P(r) distributions and bimodal dp/dP(B) distributions. The bimodal distribution of the reactive probability density can exist on a trial transition state dividing surface transverse to the solute reaction coordinate even if there is no solvent barrier. The bimodality of the reactive probability density arises from the wings of the Gaussian solvent coordinate distribution in regions away from the saddle point. The model is in good agreement with recent simulations of Na+Cl- ion pair dissociation in water. The deviations from conventional transition state theory can be interpreted as arising from solvent friction or from the participation of the solvent in the reaction coordinate. C1 Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Univ Minnesota, Inst Supercomp, Minneapolis, MN 55455 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Truhlar, DG (reprint author), Univ Minnesota, Dept Chem, 207 Pleasant St SE, Minneapolis, MN 55455 USA. RI Garrett, Bruce/F-8516-2011; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 21 TC 37 Z9 38 U1 0 U2 5 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 FEB 10 PY 2000 VL 104 IS 5 BP 1069 EP 1072 DI 10.1021/jp992430l PG 4 WC Chemistry, Physical SC Chemistry GA 281PN UT WOS:000085170000027 ER PT J AU Mesecar, AD Koshland, DE AF Mesecar, AD Koshland, DE TI Structural biology - A new model for protein stereospecificity SO NATURE LA English DT Article C1 Univ Illinois, Dept Med Chem & Pharmacognosy, Ctr Pharmaceut Biotechnol, Chicago, IL 60607 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Mesecar, AD (reprint author), Univ Illinois, Dept Med Chem & Pharmacognosy, Ctr Pharmaceut Biotechnol, 900 S Ashland Ave MC 870, Chicago, IL 60607 USA. OI Mesecar, Andrew/0000-0002-1241-2577 NR 9 TC 80 Z9 81 U1 0 U2 10 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD FEB 10 PY 2000 VL 403 IS 6770 BP 614 EP 615 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 283RD UT WOS:000085288200039 PM 10688187 ER PT J AU Voloshin, SA Poskanzer, AM AF Voloshin, SA Poskanzer, AM TI The physics of the centrality dependence of elliptic flow SO PHYSICS LETTERS B LA English DT Article ID COLLISIONS; DISTRIBUTIONS AB The centrality dependence of elliptic flow and how it is related to the physics of expansion of the system created in high energy nuclear collisions is discussed. Since in the hydro limit the centrality dependence of elliptic flow is mostly defined by the elliptic anisotropy of the overlapping region of the colliding nuclei, and in the low density limit by the product of the elliptic anisotropy and the multiplicity, we argue that the centrality dependence of elliptic flow should be a good indicator of the degree of equilibration reached in the reaction. Then we analyze experimental data obtained at AGS and SPS energies. The observed difference in the centrality dependence of elliptic flow could imply a transition from a hadronic to a partonic nature of the system evolution. Finally we exploit the multiplicity dependence of elliptic flow to make qualitative predictions for RHIC and LHC. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Wayne State Univ, Dept Phys & Astron, Detroit, MI 48201 USA. RP Voloshin, SA (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Voloshin, Sergei/I-4122-2013 NR 17 TC 110 Z9 111 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 FEB 10 PY 2000 VL 474 IS 1-2 BP 27 EP 32 DI 10.1016/S0370-2693(00)00017-4 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285KG UT WOS:000085387800005 ER PT J AU Bonini, GF Habib, S Mottola, E Rebbi, C Singleton, R Tinyakov, PG AF Bonini, GF Habib, S Mottola, E Rebbi, C Singleton, R Tinyakov, PG TI Periodic instantons in SU(2) Yang-Mills-Higgs theory SO PHYSICS LETTERS B LA English DT Article AB The properties of periodic instanton solutions of the classical SU(2) gauge theory with a Higgs doublet field are described analytically at low energies, and found numerically for all energies up to and beyond the sphaleron energy. Interesting new classes of bifurcating complex periodic instanton solutions to the Yang-Mills-Higgs equations are described. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Heidelberg, Inst Theoret Phys, D-69120 Heidelberg, Germany. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Amer Univ Cairo, Dept Sci, Physiol Sect, Cairo 11511, Egypt. Inst Nucl Res, Moscow 117312, Russia. RP Bonini, GF (reprint author), Univ Heidelberg, Inst Theoret Phys, D-69120 Heidelberg, Germany. NR 11 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 FEB 10 PY 2000 VL 474 IS 1-2 BP 113 EP 121 DI 10.1016/S0370-2693(00)00022-8 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285KG UT WOS:000085387800018 ER PT J AU Aranda, A Carone, CD Lebed, RF AF Aranda, A Carone, CD Lebed, RF TI U(2) flavor physics without U(2) symmetry SO PHYSICS LETTERS B LA English DT Article ID ANOMALIES; MODEL AB We present a model of fermion masses based on a minimal, non-Abelian discrete symmetry that reproduces the Yukawa matrices usually associated with U(2) theories of flavor. Mass and mixing angle relations that follow from the simple form of the quark and charged lepton Yukawa textures are therefore common to both theories. We show that the differing representation structure of our horizontal symmetry allows for new solutions to the solar and atmospheric neutrino problems that do not involve modification of the original charged fermion Yukawa textures, or the introduction of sterile neutrinos. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Coll William & Mary, Dept Phys, Nucl & Particle Theory Grp, Williamsburg, VA 23187 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Aranda, A (reprint author), Coll William & Mary, Dept Phys, Nucl & Particle Theory Grp, Williamsburg, VA 23187 USA. OI Aranda, Alfredo/0000-0002-8639-5167; Vancea, Ion/0000-0002-5135-9924 NR 22 TC 60 Z9 60 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 FEB 10 PY 2000 VL 474 IS 1-2 BP 170 EP 176 DI 10.1016/S0370-2693(99)01497-5 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285KG UT WOS:000085387800025 ER PT J AU Faber, M Greensite, J Olejnik, S AF Faber, M Greensite, J Olejnik, S TI First evidence for center dominance in SU(3) lattice gauge theory SO PHYSICS LETTERS B LA English DT Article DE lattice gauge theories; quantum chromodynamics; confinement ID CENTER VORTICES; CONFINEMENT; VACUUM; SIMULATIONS AB The dominance of center degrees of freedom is observed in SU(3) lattice gauge theory in maximal center gauge. The full asymptotic string tension is reproduced, after center projection, by the center elements alone. This provides further evidence for the role played by center vortices in the mechanism of color confinement in quantum chromodynamics, but more extensive simulations with a better gauge-fixing procedure are still needed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94117 USA. Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. Slovak Acad Sci, Inst Phys, SK-84228 Bratislava, Slovakia. RP Olejnik, S (reprint author), Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. EM faber@kph.tuwien.ac.at; greensit@quark.sfsu.edu; fyziolej@savba.sk RI Olejnik, Stefan/C-6145-2008; Korol, Aleksandr/A-6244-2014; Sharyy, Viatcheslav/F-9057-2014; OI Olejnik, Stefan/0000-0002-0910-7125; Korol, Aleksandr/0000-0001-8448-218X; Sharyy, Viatcheslav/0000-0002-7161-2616; Greensite, Jeff/0000-0003-1720-9436 NR 32 TC 22 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 10 PY 2000 VL 474 IS 1-2 BP 177 EP 181 DI 10.1016/S0370-2693(00)00013-7 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285KG UT WOS:000085387800026 ER PT J AU Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, CG Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Hartmann, J Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S KReisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kiatmura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Weest, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB AF Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, CG Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Hartmann, J Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S KReisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kiatmura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Weest, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB CA ZEUS Collaboration TI Measurement of the E-T(2),jet/Q(2) dependence of forward-jet production at HERA SO PHYSICS LETTERS B LA English DT Article ID INITIAL STATE RADIATION; QCD COHERENCE; SMALL-X; DISTRIBUTIONS; SCATTERING; GENERATOR; CASCADES AB The forward-jet cross section in deep inelastic e(+)p scattering has been measured using the ZEUS detector at HERA with an integrated luminosity of 6.36 pb(-1). The jet cross section is presented as a function of jet transverse energy squared, E-T,jet(2), and Q(2) in the kinematic ranges 10(-2) < E-T,jet(2)/Q(2) < 10(2) and 2.5.10(-4) < x < 8.0.10(-2). Since the perturbative QCD predictions for this cross section are sensitive to the treatment of the log(E-T,jet(2)/Q(2)) terms, this measurement provides an important test. The measured cross section is compared to the predictions of a next-to-leading order pQCD calculation as well as to various leading-order Monte Carlo models. Whereas the predictions of all models agree with the measured cross section in the region of small E-T,jet(2)/Q(2), only one model, which includes a resolved photon component, describes the data over the whole kinematic range. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, PL-31007 Krakow, Poland. Deutsch Elekt Synchrotron DESY, Hamburg, Germany. DESY Zeuthen, Zeuthen, Germany. Univ Florence, I-50121 Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, Frascati, Italy. Univ Freiburg i Br, Fak Phys, Freiburg i Br, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Exp Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, D-5170 Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Engn Phys Inst, Moscow, Russia. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. NIKHEF, Amsterdam, Netherlands. Univ Amsterdam, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany. Tel Aviv Univ, Sch Phys, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, Alessandria, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Warsaw Univ, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. RP Breitweg, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016; Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012; Goncalo, Ricardo/M-3153-2016 OI De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240; dusini, stefano/0000-0002-1128-0664; Goncalo, Ricardo/0000-0002-3826-3442 NR 23 TC 25 Z9 25 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 10 PY 2000 VL 474 IS 1-2 BP 223 EP 233 DI 10.1016/S0370-2693(99)01478-1 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 285KG UT WOS:000085387800031 ER PT J AU Terborg, R Hoeft, JT Polcik, M Lindsay, R Schaff, O Bradshaw, AM Toomes, RL Booth, NA Woodruff, DP Rotenberg, E Denlinger, J AF Terborg, R Hoeft, JT Polcik, M Lindsay, R Schaff, O Bradshaw, AM Toomes, RL Booth, NA Woodruff, DP Rotenberg, E Denlinger, J TI The coverage dependence of the local structure of C on Ni(100): a structural precursor to adsorbate-induced reconstruction SO SURFACE SCIENCE LA English DT Article DE carbon; chemisorption; nickel; photoelectron diffraction; surface reconstruction; surface structure ID MODE PHOTOELECTRON DIFFRACTION; INDUCED SURFACE STRESS; PHONON-DISPERSION; CARBON; RESOLUTION; CU(110); SYSTEM; LEED AB The local structure around adsorbed carbon atoms on Ni(100) has been determined by C Is scanned-energy mode photoelectron diffraction both at low coverage (0.15 ML) and at 0.5 ML in the 'clock'-reconstructed (2 x 2)p4g phase. At low coverage the C atoms occupy simple undistorted hollow sites; the radial strain of the Ni atoms surrounding the adsorbed carbon, proposed on the basis of STM images, is not found. The comparative study of the (2 x 2)p4g phase confirms the structural parameters of earlier studies, but allows direct comparison between the two phases free from systematic errors. The C-Ni near-neighbour distances to both top and second layer Ni atoms are unchanged by reconstruction, but the Ni-Ni nearest-neighbour distance in the top layer increases significantly. This implies that the adsorbate-induced compressive stress is associated with Ni-Ni, rather than Ni-C, repulsion as has previously been proposed. Special care has been taken to check for coupling of structural parameters in the analysis which might influence the precision of these comparisons, and a new methodology for identifying and assessing such parameter coupling is described. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. MPG Arbeitsgrp Elektronensyst, Fritz Haber Inst, D-14195 Berlin, Germany. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Woodruff, DP (reprint author), Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RI Rotenberg, Eli/B-3700-2009 OI Rotenberg, Eli/0000-0002-3979-8844 NR 29 TC 31 Z9 31 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 10 PY 2000 VL 446 IS 3 BP 301 EP 313 DI 10.1016/S0039-6028(99)01159-0 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 285LN UT WOS:000085390700016 ER PT J AU Reardon, BJ Bingert, SR AF Reardon, BJ Bingert, SR TI Inversion of tantalum micromechanical powder consolidation and sintering models using Bayesian inference and genetic algorithms SO ACTA MATERIALIA LA English DT Article DE powder consolidation; sintering; hot isostatic pressing (HIP); computer simulation; genetic algorithms AB A Bayesian enhanced genetic algorithm (GA) addresses the inverse and ill-posed problem of optimizing the 19 parameters of micromechanical powder densification models for tantalum using limited and uncertain data sets that leave the optimization problem underdetermined. Additionally, the posterior probability density evolved by the GA provides a parameter sensitivity analysis as well as a guide to experimental design which significantly assists in the development of accurate models with a minimum of experimentation. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reardon, BJ (reprint author), Univ Calif Los Alamos Natl Lab, MST-6,MS G770, Los Alamos, NM 87545 USA. NR 37 TC 5 Z9 5 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB 9 PY 2000 VL 48 IS 3 BP 647 EP 658 DI 10.1016/S1359-6454(99)00407-3 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 288KV UT WOS:000085562700004 ER PT J AU Chen, D Gilbert, CJ Zhang, XF Ritchie, RO AF Chen, D Gilbert, CJ Zhang, XF Ritchie, RO TI High-temperature cyclic fatigue-crack growth behavior in an in situ toughened silicon carbide SO ACTA MATERIALIA LA English DT Article DE ceramics; structural SiC; mechanical properties (fatigue); high temperature; grain bridging ID R-CURVE BEHAVIOR; B-C ADDITIONS; POLYCRYSTALLINE ALUMINA; NITRIDE CERAMICS; FRACTURE-TOUGHNESS; MONOLITHIC ALUMINA; FRICTIONAL-WEAR; MECHANISMS; COMPOSITE; CREEP AB The growth of fatigue cracks at elevated temperatures (25-1300 degrees C) is examined under cyclic loading in an in situ toughened, monolithic silicon carbide with AI-B-C additions (termed ABC-SiC), with specific emphasis on the roles of temperature, load ratio, cyclic frequency, and loading mode (static vs cyclic). Extensive crack-growth data are presented, based on measurements from an electrical potential-drop crack-monitoring technique, adapted for use on ceramics at high temperatures. It was found that at equivalent stress-intensity levels, crack velocities under cyclic loads were significantly faster than those under static loads. Fatigue thresholds were found to decrease with increasing temperature up to 1200 degrees C; behavior at 1300 degrees C, however, was similar to that at 1200 degrees C. Moreover, no effect of frequency was detected (between 3 and 1000 Hz), nor evidence of creep cavitation or crack bridging by viscous ligaments or grain-boundary glassy phases in the crack wake. Indeed, fractography and crack-path sectioning revealed a fracture mode at 1200-1300 degrees C that was essentially identical to that at room temperature, i.e. predominantly intergranular cracking with evidence of grain bridging in the crack wake. Such excellent crack-growth resistance is attributed to a process of grain-boundary microstructural evolution at elevated temperatures, specifically involving crystallization of the amorphous grain-boundary films/phases. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. 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. RP Ritchie, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 60 TC 24 Z9 24 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB 9 PY 2000 VL 48 IS 3 BP 659 EP 674 DI 10.1016/S1359-6454(99)00406-1 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 288KV UT WOS:000085562700005 ER PT J AU Tellers, DM Bergman, RG AF Tellers, DM Bergman, RG TI C-H bond activation by a rare cationic iridium dinitrogen complex. An important electronic effect in the chemistry of the hydridotris(pyrazolyl)borate ligand SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PINCER COMPLEX; DEHYDROGENATION; RHODIUM C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Bergman, RG (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 26 TC 70 Z9 70 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 FEB 9 PY 2000 VL 122 IS 5 BP 954 EP 955 DI 10.1021/ja993347e PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 283UP UT WOS:000085294700027 ER PT J AU Rempe, SB Pratt, LR Hummer, G Kress, JD Martin, RL Redondo, A AF Rempe, SB Pratt, LR Hummer, G Kress, JD Martin, RL Redondo, A TI The hydration number of Li(+) in liquid water SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; DILUTE AQUEOUS-SOLUTIONS; SET AB-INITIO; ELECTROLYTE-SOLUTIONS; NEUTRON-SCATTERING; METAL-CATIONS; IONS; CL; MOBILITY; SHELL C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Pratt, LR (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Rempe, Susan/H-1979-2011; Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 44 TC 133 Z9 134 U1 3 U2 22 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 FEB 9 PY 2000 VL 122 IS 5 BP 966 EP 967 DI 10.1021/ja9924750 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 283UP UT WOS:000085294700033 ER PT J AU Dai, S Burleigh, MC Ju, YH Gao, HJ Lin, JS Pennycook, SJ Barnes, CE Xue, ZL AF Dai, S Burleigh, MC Ju, YH Gao, HJ Lin, JS Pennycook, SJ Barnes, CE Xue, ZL TI Hierarchically imprinted sorbents for the separation of metal ions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MESOPOROUS MOLECULAR-SIEVES; PORE STRUCTURE; TEMPLATES; POLYMERS; OXIDES C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RP Dai, S (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Dai, Sheng/K-8411-2015 OI Dai, Sheng/0000-0002-8046-3931 NR 28 TC 178 Z9 183 U1 3 U2 47 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 FEB 9 PY 2000 VL 122 IS 5 BP 992 EP 993 DI 10.1021/ja993168x PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 283UP UT WOS:000085294700046 ER PT J AU Forsythe, KM Gray, SK AF Forsythe, KM Gray, SK TI A transition state real wave packet approach for obtaining the cumulative reaction probability SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISCRETE VARIABLE REPRESENTATION; THERMAL RATE CONSTANTS; ABSORBING BOUNDARY-CONDITIONS; QUANTUM CALCULATIONS; CHEMICAL-REACTIONS; H-2+OH REACTION; SCATTERING; DYNAMICS; ACCURATE; EQUATION AB We show how the transition state wave packet method of Zhang and Light can be applied within a real wave packet formalism. We also implement random superpositions into the approach, as in the recent work of Matzkies and Manthe, which can significantly reduce the number of propagations at higher temperatures. The net result is a very efficient approach for calculating the cumulative reaction probability, and hence the thermal rate constant, for bimolecular chemical reactions. Full dimensional quantum calculations, including all relevant total angular momenta, of the cumulative reaction probability and thermal rate constant for the D + H-2--> HD + H are used as illustration. [S0021-9606(00)01205-8]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Forsythe, KM (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 49 TC 13 Z9 13 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 FEB 8 PY 2000 VL 112 IS 6 BP 2623 EP 2633 DI 10.1063/1.480836 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000007 ER PT J AU Shea, DA Goodman, L White, MG AF Shea, DA Goodman, L White, MG TI Acetone n-radical cation internal rotation spectrum: The torsional potential surface SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RYDBERG STATES; RESOLUTION; SPECTROSCOPY; MOLECULES; TRANSITION; LIFETIMES AB The one color REMPI and two color ZEKE-PFI spectra of acetone-d(3) have been recorded. The 3p(x) Rydberg state of acetone-d(3) lies at 59 362.3 cm(-1) and both of the torsional modes are visible in this spectrum. The antigearing Rydberg (a(2)) mode, v(12)*, has a frequency of 62.5 cm(-1), while the previously unobserved gearing (b(1)) mode, v(17)*, is found at 119.1 cm(-1). An ionization potential of 78 299.6 cm(-1) for acetone-d(3) has been measured. In acetone-d(3) n-radical cation ground state, the fundamentals of both of the torsional modes have been observed, v(12)(+) at 51.0 cm(-1) and v(17)(+) at 110.4 cm(-1), while the first overtone of v(12)(+) has been measured at 122.4 cm(-1). Deuterium shifts show that v(12)(+) behaves like a local C-3 upsilon rotor, but that v(17)(+) is canonical. Combining this data with that for acetone-d(0) and aacetone-d(6) has allowed us to fit the observed frequencies to a torsional potential energy surface based on an ab initio C-2 upsilon cation ground state geometry. This potential energy surface allows for prediction of the v(17) vibration in acetone-d(0) and acetone-d(6). The barrier to synchronous rotation is higher in the cation ground state than in the neutral ground state, but significantly lower than in the 3s Rydberg state. The 3p(x) Rydberg and cation ground state potential energy surfaces are found to be very similar to each other, strongly supporting the contention that the 3p(x) Rydberg state has C-2 upsilon geometry and is a good model for the ion core. The altered 3s Rydberg state potential surface suggests this state has significant valence character. (C) 2000 American Institute of Physics. [S0021-9606(00)01206-X]. C1 Rutgers State Univ, Wright & Rieman Chem Labs, New Brunswick, NJ 08903 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Shea, DA (reprint author), Rutgers State Univ, Wright & Rieman Chem Labs, New Brunswick, NJ 08903 USA. NR 36 TC 10 Z9 10 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 2000 VL 112 IS 6 BP 2762 EP 2768 DI 10.1063/1.480850 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000021 ER PT J AU Raptis, CA Bacon, JA Pratt, ST AF Raptis, CA Bacon, JA Pratt, ST TI Double-resonance spectroscopy of autoionizing states of ammonia SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ZEKE PHOTOELECTRON-SPECTROSCOPY; HIGH RYDBERG STATES; VIBRATIONAL AUTOIONIZATION; ENERGY; IONIZATION; PHOTOIONIZATION; NH3; DYNAMICS; PREDISSOCIATION; SELECTION AB New double-resonance ionization data are presented on the autoionizing Rydberg states of NH3 excited via selected rotational levels of the (C) over tilde' (1)A(1)(0100) and (0200) states. Extrapolation of the Rydberg series provides a determination of the adiabatic ionization energy of NH3 that is in excellent agreement with that obtained by using zero kinetic energy photoelectron spectroscopy (ZEKE-PES). A comparison is presented between the field-free spectrum obtained by using a time-of-flight mass spectrometer and the 1-Tesla-spectrum obtained by using a magnetic-bottle electron spectrometer. Finally, the rotational and vibrational autoionization mechanisms are discussed. [S0021-9606(00)01006-0]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Raptis, CA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 37 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 2000 VL 112 IS 6 BP 2815 EP 2825 DI 10.1063/1.480856 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000027 ER PT J AU Xu, L Ogletree, DF Salmeron, M Tang, HA Gui, J Marchon, B AF Xu, L Ogletree, DF Salmeron, M Tang, HA Gui, J Marchon, B TI De-wetting of lubricants on hard disks SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLARIZATION FORCE MICROSCOPY; SOLID-SURFACES; WATER; CONDENSATION; FILMS; MICA AB The de-wetting process of Zdol-type lubricants on hard disks has been studied at the molecular scale with scanning polarization force microscopy (SPFM) and ellipsometry. It was found that de-wetting occurred over hours to days when the initial lubricant layer was thicker than one monolayer (similar to 20 Angstrom thick). De-wetting was found to take place in a layered fashion for Zdol-TX and Z-Tetraol, with weakly bound second layers accreting into droplets, however, no layering was seen for Zdol during de-wetting, only droplets. The droplets eventually grew to the point where they could be observed by optical microscopy. In all cases, the first monolayer remained bound to the surface. Although the atomic force microscopy (AFM) tip could easily penetrate this first layer, it did not remove it. (C) 2000 American Institute of Physics. [S0021-9606(00)71306-7]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Seagate Technol Inc, Adv Tribol Res Grp, Fremont, CA 94538 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Marchon, Bruno/H-5665-2013; Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 17 TC 44 Z9 44 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 2000 VL 112 IS 6 BP 2952 EP 2957 DI 10.1063/1.480868 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000041 ER PT J AU Snyder, JA Jaffe, JE Gutowski, M Lin, ZJ Hess, AC AF Snyder, JA Jaffe, JE Gutowski, M Lin, ZJ Hess, AC TI LDA and GGA calculations of alkali metal adsorption at the (001) surface of MgO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; DOPED MAGNESIUM-OXIDE; MGO(001) SURFACE; HELIUM DIFFRACTION; FIRST-PRINCIPLES; MGO(100); ENERGY; STATE; ATOMS; APPROXIMATION AB The adsorption geometry, binding energy and electronic structure of alkali metal overlayers on the MgO (001) surface have been studied by means of density functional theory, using Gaussian-type orbitals to expand the wave functions and electronic charge density. A two-dimensionally periodic slab of MgO with alkali metal adsorbed at one surface was used to model the semi-infinite system. Li, Na, and K were considered at both half- and quarter-monolayer coverage. Results were compared for the local density approximation and for two different forms of the generalized gradient approximation. In all cases Li was found to interact with the surface approximately twice as strongly as Na and three times as strongly as K. The epitaxial binding energies were, however, always less than or close to the bulk cohesive energies of the respective alkali metals, suggesting an instability of the adsorbed film toward the formation of two- or three-dimensional islands, in agreement with experiment. Spin polarized and unpolarized calculations were compared to detect metal-insulator transitions in the alkali overlayer. Only Li adsorbed at 1:4 coverage was found to have lower energy in a spin polarized (hence nonmetallic) state. (C) 2000 American Institute of Physics. [S0021-9606(00)71006-3]. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Gdansk, Dept Chem, PL-08952 Gdansk, Poland. RP Snyder, JA (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Lin, Zijing/D-4050-2009 NR 39 TC 37 Z9 37 U1 1 U2 10 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 FEB 8 PY 2000 VL 112 IS 6 BP 3014 EP 3022 DI 10.1063/1.480875 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000049 ER PT J AU Hooper, JB McCoy, JD Curro, JG AF Hooper, JB McCoy, JD Curro, JG TI Density functional theory of simple polymers in a slit pore. I. Theory and efficient algorithm SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FORMULATION; LIQUIDS; MELTS AB Previous applications of density functional (DF) theory required a single chain Monte Carlo simulation to be performed within a self-consistent loop. In the current work, a methodology is developed which permits the simulation to be taken out of the iterative loop. Consequently, the calculation of the self-consistent, medium-induced potential, or field, is decoupled from the simulation. This approach permits different densities, different forms of U-M(r), and different wall-polymer interactions to be investigated from a single Monte Carlo simulation. The increase in computational efficiency is immense. (C) 2000 American Institute of Physics. [S0021-9606(00)52905-5]. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP McCoy, JD (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. RI McCoy, John/B-3846-2010 OI McCoy, John/0000-0001-5404-1404 NR 13 TC 65 Z9 65 U1 0 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 FEB 8 PY 2000 VL 112 IS 6 BP 3090 EP 3093 DI 10.1063/1.480884 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000058 ER PT J AU Hooper, JB Pileggi, MT McCoy, JD Curro, JG Weinhold, JD AF Hooper, JB Pileggi, MT McCoy, JD Curro, JG Weinhold, JD TI Density functional theory of simple polymers in a slit pore. II. The role of compressibility and field type SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYMMETRICAL DIBLOCK COPOLYMERS; NONUNIFORM POLYATOMIC SYSTEMS; SELF-CONSISTENT-FIELD; HARD-SPHERE MIXTURES; CHAIN MOLECULES; IMMISCIBLE POLYMERS; QUANTUM-SYSTEMS; FORMULATION; LIQUIDS; APPROXIMATION AB Simple tangent, hard site chains near a hard wall are modeled with a density functional (DF) theory that uses the direct correlation function, c(r), as its "input." Two aspects of this DF theory are focused upon: (1) the consequences of variations in c(r)'s detailed form; and (2) the correct way to introduce c(r) into the DF formalism. The most important aspect of c(r) is found to be its integrated value, c(0). Indeed, it appears that, for fixed c(0), all reasonable guesses of the detailed shape of c(r) result in surprisingly similar density distributions, rho(r). Of course, the more accurate the c(r), the better the rho(r). As long as the length scale introduced by c(r) is roughly the hard site diameter and as long as the solution remains liquid-like, the rho(r) is found to be in good agreement with simulation results. The c(r) is used in DF theory to calculate the medium-induced potential, U-M(r), from the density distribution, rho(r). The form of U-M(r) can be chosen to be one of a number of different forms. It is found that the forms for U-M(r)which yield the most accurate results for the wall problem are also those which were suggested as accurate in previous, related studies. (C) 2000 American Institute of Physics. [S0021-9606(00)53005-0]. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP McCoy, JD (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. RI McCoy, John/B-3846-2010 OI McCoy, John/0000-0001-5404-1404 NR 42 TC 40 Z9 40 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 FEB 8 PY 2000 VL 112 IS 6 BP 3094 EP 3103 DI 10.1063/1.480885 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 279KM UT WOS:000085043000059 ER PT J AU Datta, A Kmetko, J Richter, AG Yu, CJ Dutta, P Chung, KS Bai, JM AF Datta, A Kmetko, J Richter, AG Yu, CJ Dutta, P Chung, KS Bai, JM TI Effect of headgroup dissociation on the structure of Langmuir monolayers SO LANGMUIR LA English DT Article ID X-RAY-DIFFRACTION; LIPID MONOLAYERS; PHASE-DIAGRAM; WATER; SYNCHROTRON; TRANSITIONS; INTERFACE; PRESSURE; IONS AB We present results of grazing incidence X-ray diffraction studies concerning the effect of pH (and thus, of headgroup dissociation) on Langmuir monolayers of fatty acids, in the absence of any divalent cations in the aqueous subphase. An increase in pH transforms the distorted-hexagonal S phase first to the partially disordered Rotator-I phase with less distortion, and then to the completely disordered Rotator-II phase with an undistorted hexagonal structure. The S-Rotator-I and Rotator-I-Rotator-II transitions are pushed to lower temperatures with increase in pH. The fact that the effects of pH increase are almost identical to the effects of increasing temperature indicates the important role of headgroup-headgroup interactions in these monolayer phases. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37830 USA. RP Datta, A (reprint author), Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RI Datta, Alokmay/C-1252-2008; Bai, Jianming/O-5005-2015 NR 22 TC 23 Z9 23 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 8 PY 2000 VL 16 IS 3 BP 1239 EP 1242 DI 10.1021/la990540d PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 281UJ UT WOS:000085178900052 ER PT J AU Carpick, RW Sasaki, DY Burns, AR AF Carpick, RW Sasaki, DY Burns, AR TI First observation of mechanochromism at the nanometer scale SO LANGMUIR LA English DT Article ID ATOMIC-FORCE MICROSCOPE; LANGMUIR-BLODGETT-FILMS; FIELD OPTICAL MICROSCOPY; POLYDIACETYLENE LIPOSOMES; SHEAR-FORCE; FIBER TIPS; FLUORESCENCE; DIACETYLENE; ACID; DIFFRACTION AB A mechanically induced color transition ("mechanochromism") in poly(diacetylene) thin films has been generated at the nanometer scale using the tips of two different scanning probe microscopes. A blue-to-red chromatic transition in poly(diacetylene) molecular trilayer films, polymerized fr om 10,12-pentacosadiynoic acid (poly-PCDA), was found to result from shear forces acting between the tip and the poly-PCDA molecules, as independently observed with near-field scanning optical microscopy and atomic force microscopy (AFM), Red domains were identified by a fluorescence emission signature. Transformed regions as small as 30 nm in width were observed with AFM. The irreversibly transformed domains preferentially grow along the polymer backbone direction. Significant rearrangement of poly-PCDA bilayer segments is observed by AFM in transformed regions. The rearrangement of these segments appears to be a characteristic feature of the transition. To our knowledge, this is the first observation of nanometer-scale mechanochromism in any material. C1 Sandia Natl Labs, Nanomol Mat & Interfaces Dept, Albuquerque, NM 87185 USA. RP Burns, AR (reprint author), Sandia Natl Labs, Nanomol Mat & Interfaces Dept, POB 5800, Albuquerque, NM 87185 USA. NR 42 TC 144 Z9 146 U1 14 U2 67 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 8 PY 2000 VL 16 IS 3 BP 1270 EP 1278 DI 10.1021/la990706a PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 281UJ UT WOS:000085178900057 ER PT J AU Brezina, M Cleary, AJ Falgout, RD Henson, VE Jones, JE Manteuffel, TA McCormick, SF Ruge, JW AF Brezina, M Cleary, AJ Falgout, RD Henson, VE Jones, JE Manteuffel, TA McCormick, SF Ruge, JW TI Algebraic multigrid based on element interpolation (AMGE) SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE algebraic multigrid; finite elements; interpolation weights ID VARIATIONAL-PROBLEMS; CONVERGENCE; ASSUMPTIONS AB We introduce AMGe, an algebraic multigrid method for solving the discrete equations that arise in Ritz-type finite element methods for partial differential equations. Assuming access to the element sti ness matrices, we have that AMGe is based on the use of two local measures, which are derived from global measures that appear in existing multigrid theory. These new measures are used to determine local representations of algebraically smooth error components that provide the basis for constructing effective interpolation and, hence, the coarsening process for AMG. Here, we focus on the interpolation process; choice of the coarse grids based on these measures is the subject of current research. We develop a theoretical foundation for AMGe and present numerical results that demonstrate the efficacy of the method. C1 Univ Colorado, Dept Appl Math, Boulder, CO 80309 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. RP Brezina, M (reprint author), Univ Colorado, Dept Appl Math, Campus Box 526, Boulder, CO 80309 USA. EM mbrezina@colorado.edu; cleary@llnl.gov; rfalgout@llnl.gov; vhenson@llnl.gov; jjones@llnl.gov; tmanteuf@colorado.edu; stevenm@colorado.edu; jruge@colorado.edu NR 24 TC 132 Z9 141 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD FEB 8 PY 2000 VL 22 IS 5 BP 1570 EP 1592 PG 23 WC Mathematics, Applied SC Mathematics GA 414PH UT WOS:000167674900005 ER PT J AU Ustundag, E Clausen, B Bourke, MAM AF Ustundag, E Clausen, B Bourke, MAM TI Neutron diffraction study of the reduction of NiAl2O4 SO APPLIED PHYSICS LETTERS LA English DT Article ID METAL-CERAMIC MICROSTRUCTURES; NICKEL ALUMINATE SPINEL; AL-O SYSTEM AB The reduction of a solid NiAl2O4 cylinder to a metal-ceramic composite consisting of Ni particles in an Al2O3 matrix was monitored in situ at 1220 degrees C with neutron powder diffraction. The reaction kinetics was determined with a time resolution of 30 min. The reduction is associated with a volume shrinkage. A comparison of finite element calculations and the changes in the measured lattice parameters suggests that creep has relaxed the residual strains that would otherwise result from the volume shrinkage. The data also indicate that structural evolution in unreduced NiAl2O4 via a change in the cationic sublattice towards inverse spinel occurred and that led to a variation in lattice parameters. (C) 2000 American Institute of Physics. [S0003-6951(00)02806-0]. C1 CALTECH, Keck Lab, Dept Mat Sci, Pasadena, CA 91125 USA. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Ustundag, E (reprint author), CALTECH, Keck Lab, Dept Mat Sci, Pasadena, CA 91125 USA. RI Ustundag, Ersan/C-1258-2009; Clausen, Bjorn/B-3618-2015 OI Ustundag, Ersan/0000-0002-0812-7028; Clausen, Bjorn/0000-0003-3906-846X NR 13 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 7 PY 2000 VL 76 IS 6 BP 694 EP 696 DI 10.1063/1.125864 PG 3 WC Physics, Applied SC Physics GA 279YY UT WOS:000085075200012 ER PT J AU Noh, M Jellison, GE Namavar, F Weitering, HH AF Noh, M Jellison, GE Namavar, F Weitering, HH TI Isolation of a metallic Si(111)7x7 surface reconstruction via separation by implanted oxygen SO APPLIED PHYSICS LETTERS LA English DT Article ID 2-MODULATOR GENERALIZED ELLIPSOMETRY; SPECTROSCOPY; INTERFACE; SI AB High-quality Si(111)7x7 surface reconstructions have been observed on (111)-oriented Si/SiO2/Si substrates, prepared via separation by implantation of oxygen, or "SIMOX," with top layer thicknesses as small as 220 Angstrom. Scanning tunneling microscopy and spectroscopy data indicate that the electrically and physically isolated top layer is electrically conducting, in contrast to that of (100) SIMOX material, which accumulates charge under typical imaging conditions. We speculate that the 7x7 reconstruction on (111) SIMOX material is an efficient conduction channel, allowing atomic resolution imaging of the isolated Si top layer. (C) 2000 American Institute of Physics. [S0003-6951(00)00506-4]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Spire Corp, Bedford, MA 01730 USA. RP Weitering, HH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 14 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 7 PY 2000 VL 76 IS 6 BP 733 EP 735 DI 10.1063/1.125877 PG 3 WC Physics, Applied SC Physics GA 279YY UT WOS:000085075200025 ER PT J AU Aytug, T Wu, JZ Cantoni, C Verebelyi, DT Specht, ED Paranthaman, M Norton, DP Christen, DK Ericson, RE Thomas, CL AF Aytug, T Wu, JZ Cantoni, C Verebelyi, DT Specht, ED Paranthaman, M Norton, DP Christen, DK Ericson, RE Thomas, CL TI Growth and superconducting properties of YBa2Cu3O7-delta films on conductive SrRuO3 and LaNiO3 multilayers for coated conductor applications SO APPLIED PHYSICS LETTERS LA English DT Article ID CRITICAL-CURRENT DENSITY; THIN-FILMS; TAPES; DEPOSITION; JUNCTIONS AB Conductive multilayers of YBa2Cu3O7-delta/SrRuO3/LaNiO3 (YBCO/SRO/LNO), YBCO/SRO, and YBCO/LNO were grown epitaxially on single-crystal LaAlO3 and SrTiO3 substrates. Property characterizations revealed that the YBCO films on SRO and SRO/LNO buffer structures have excellent structural and superconducting properties. The YBCO/LNO, however, suffers degradation in superconducting transition temperatures and critical current densities, despite a good crystalline structure. The SRO/LNO bilayer showed excellent electrical contact with YBCO. These results have demonstrated the structural and chemical compatibility of SRO/LNO multilayers with YBCO and their potential use as conductive buffer layers for YBCO-based coated conductors as well as for other high-temperature superconducting applications. (C) 2000 American Institute of Physics. [S0003-6951(00)04206-6]. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. 3M Co, St Paul, MN 55144 USA. RP Aytug, T (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RI Specht, Eliot/A-5654-2009; Paranthaman, Mariappan/N-3866-2015; Cantoni, Claudia/G-3031-2013 OI Specht, Eliot/0000-0002-3191-2163; Paranthaman, Mariappan/0000-0003-3009-8531; Cantoni, Claudia/0000-0002-9731-2021 NR 15 TC 21 Z9 23 U1 1 U2 10 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 FEB 7 PY 2000 VL 76 IS 6 BP 760 EP 762 DI 10.1063/1.125886 PG 3 WC Physics, Applied SC Physics GA 279YY UT WOS:000085075200034 ER PT J AU Li, JW Duewer, F Gao, C Chang, HY Xiang, XD Lu, YL AF Li, JW Duewer, F Gao, C Chang, HY Xiang, XD Lu, YL TI Electro-optic measurements of the ferroelectric-paraelectric boundary in Ba1-xSrxTiO3 materials chips SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS AB The combinatorial material chip strategy is used to study the ferroelectric-paraelectric phase boundary of the Ba1-xSrxTiO3 thin film system. The electro-optic (EO) effect at different compositions is measured using a modified direct-current/alternating-current birefringence EO measurement technique. We find that Ba1-xSrxTiO3 thin films exhibit relaxor like behavior with diffused ferroelectric domains existing well past the previously defined ferroelectric-paraelectric boundary (x > 0.3). (C) 2000 American Institute of Physics. [S0003-6951(00)01006-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NZ Appl Technol Corp, Woburn, MA 01801 USA. RP Xiang, XD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Xiang, Xiaodong/A-9445-2012; Xiang, Xiaodong/A-5936-2017 NR 8 TC 47 Z9 48 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 7 PY 2000 VL 76 IS 6 BP 769 EP 771 DI 10.1063/1.125889 PG 3 WC Physics, Applied SC Physics GA 279YY UT WOS:000085075200037 ER PT J AU Yoo, JH Jeong, SH Mao, XL Greif, R Russo, RE AF Yoo, JH Jeong, SH Mao, XL Greif, R Russo, RE TI Evidence for phase-explosion and generation of large particles during high power nanosecond laser ablation of silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE; FILMS AB The craters resulting from high-irradiance (1x10(9)-1x10(11) W/cm(2)) single-pulse laser ablation of single-crystal silicon show a dramatic increase in volume at a threshold irradiance of 2.2x10(10) W/CM2. Time-resolved shadowgraph images show ejection of large particulates from the sample above this threshold irradiance, with a time delay similar to 300 ns. A numerical model was used to estimate the thickness of a superheated layer near the critical state. Considering the transformation of liquid metal into liquid dielectric near the critical state (i.e., induced transparency), the calculated thickness of the superheated layer at a delay time of 200-300 ns agreed with the measured crater depths. This agreement suggests that induced transparency promotes the formation of a deep superheated layer, and explosive boiling within this layer leads to particulate ejection from the sample. (C) 2000 American Institute of Physics. [S0003-6951(00)03206-X]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Kwangju Inst Sci & Technol, Kwangju 500712, South Korea. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 21 TC 153 Z9 157 U1 5 U2 37 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 FEB 7 PY 2000 VL 76 IS 6 BP 783 EP 785 DI 10.1063/1.125894 PG 3 WC Physics, Applied SC Physics GA 279YY UT WOS:000085075200042 ER PT J AU Allen, PG Bucher, JJ Shuh, DK Edelstein, NM Craig, I AF Allen, PG Bucher, JJ Shuh, DK Edelstein, NM Craig, I TI Coordination chemistry of trivalent lanthanide and actinide ions in dilute and concentrated chloride solutions SO INORGANIC CHEMISTRY LA English DT Article ID ABSORPTION FINE-STRUCTURE; ANOMALOUS CONCENTRATION-DEPENDENCE; HYDRATION NUMBER CHANGE; X-RAY-DIFFRACTION; INNER-SPHERE; PERCHLORATE SOLUTIONS; AQUEOUS-SOLUTIONS; LUMINESCENCE LIFETIMES; STRUCTURE SPECTROSCOPY; PARAMETRIC ANALYSIS AB We have used EXAFS spectroscopy to investigate the inner sphere coordination of trivalent lanthanide (Ln) and actinide (An) ions in aqueous solutions as a function of increasing chloride concentration. At low chloride concentration, the hydration numbers and corresponding Ln,An-O bond lengths an as follows: La3+, N = 9.2, R = 2.54 Angstrom; Ce3+, N = 9.3, R = 2.52 Angstrom; Nd3+, N = 9.5, R = 2.49 Angstrom; Eu3+, N = 9.3, R = 2.43 Angstrom; Yb3+, N = 8.7, R = 2.32 Angstrom; Y3+, N = 9.7, R = 2.36 Angstrom; Am3+, N = 10.3, R = 2.48 Angstrom; Cm3+, N = 10.2, R = 2.45 Angstrom. In ca. 14 M LiCl, the early Ln(3+) ions (La, Ce, Nd, and Eu) show inner sphere C1- complexation along with a loss of H2O. The average chloride coordination numbers and Ln-CI bond lengths are as follows: La3+, N = 2.1, R = 2.92 Angstrom; Ce3+, N = 1.8, R = 2.89 Angstrom; Nd3+, N = 1.9, R = 2.85 Angstrom; Eu3+, N = 1.1, R = 2.81 Angstrom The extent of Cl- ion complexation decreases going across the Ln(3+) series to the point where Yb3+ shows no Cl- complexation and no loss of coordinated water molecules. The actinide ions, Am3+ and Cm3+, show the same structural effects as the early Ln(3+) ions, i.e., Cl(-)ion replacement of the H2O at high chloride thermodynamic activities. The Cl(-)ion coordination numbers and An-CI bond lengths are: Am3+, N = 1.8, R = 2.81 Angstrom; Cm3+, N = 2.4, R = 2.76 A. When combined with results reported previously for Pu3+ which showed no significant chloride complexation in 12 M LiCl, these results suggest that the extent of chloride complexation is increasing across the An(3+) series. The origin of the differences in chloride complex formation between the Ln(3+) and An(3+) ions and the relevance to earlier work is discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Actinide Chem Grp, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Seaborg Inst Transactinium Sci, Livermore, CA 94551 USA. RP Allen, PG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Actinide Chem Grp, Berkeley, CA 94720 USA. OI Craig, Ian/0000-0003-4481-3700 NR 42 TC 188 Z9 189 U1 4 U2 61 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 FEB 7 PY 2000 VL 39 IS 3 BP 595 EP 601 DI 10.1021/ic9905953 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 283FQ UT WOS:000085266100031 PM 11229583 ER PT J AU Taunton, J Rowning, BA Coughlin, ML Wu, M Moon, RT Mitchison, TJ Larabell, CA AF Taunton, J Rowning, BA Coughlin, ML Wu, M Moon, RT Mitchison, TJ Larabell, CA TI Actin-dependent propulsion of endosomes and lysosomes by recruitment of N-WASP SO JOURNAL OF CELL BIOLOGY LA English DT Article DE actin assembly; fertilization; Wiskott-Aldrich; phorbol ester; Rho-GDI ID CORTICAL GRANULE EXOCYTOSIS; ALDRICH-SYNDROME PROTEIN; XENOPUS-LAEVIS; CELL-CYCLE; KINASE-C; EGGS; POLYMERIZATION; TRANSLOCATION; LOCALIZATION; MICROTUBULES AB We examined the spatial and temporal control of actin assembly in living Xenopus eggs. Within minutes of egg activation, dynamic actin-rich comet tails appeared on a subset of cytoplasmic vesicles that were enriched in protein kinase C (PKC), causing the vesicles to move through the cytoplasm. Actin comet tail formation in vivo was stimulated by the PKC activator phorbol myristate acetate (PMA), and this process could be reconstituted in a cell-free system. We used this system to define the characteristics that distinguish vesicles associated with actin comet tails from other vesicles in the extract. We found that the protein, N-WASP, was recruited to the surface of every vesicle associated with an actin comet tail, suggesting that vesicle movement results from actin assembly nucleated by the Arp2/3 complex, the immediate downstream target of N-WASP, The motile vesicles accumulated the dye acridine orange, a marker for endosomes and lysosomes. Furthermore, vesicles associated with actin comet tails had the morphological features of multivesicular endosomes as revealed by electron microscopy. Endosomes and lysosomes from mammalian cells preferentially nucleated actin assembly and moved in the Xenopus egg extract system. These results define endosomes and lysosomes as recruitment sites for the actin nucleation machinery and demonstrate that actin assembly contributes to organelle movement. Conversely, by nucleating actin assembly, intracellular membranes may contribute to the dynamic organization of the actin cytoskeleton. C1 Harvard Univ, Sch Med, Dept Cell Biol, Boston, MA 02115 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Washington, Sch Med, Dept Pharmacol, Howard Hughes Med Inst, Seattle, WA 98195 USA. RP Taunton, J (reprint author), Harvard Univ, Sch Med, Dept Cell Biol, 240 Longwood Ave, Boston, MA 02115 USA. RI Moon, Randall/B-1743-2014 OI Moon, Randall/0000-0002-9352-1408 FU NIGMS NIH HHS [GM35126, R01 GM035126] NR 39 TC 302 Z9 308 U1 0 U2 5 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD FEB 7 PY 2000 VL 148 IS 3 BP 519 EP 530 DI 10.1083/jcb.148.3.519 PG 12 WC Cell Biology SC Cell Biology GA 283DG UT WOS:000085260400011 PM 10662777 ER PT J AU Paxton, AT van Schilfgaarde, M MacKenzie, M Craven, AJ AF Paxton, AT van Schilfgaarde, M MacKenzie, M Craven, AJ TI The near-edge structure in energy-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID X-RAY-ABSORPTION; GENERALIZED GRADIENT APPROXIMATION; ROCK-SALT STRUCTURE; MOMENTS DEVELOPMENTS; UNOCCUPIED STATES; STRUCTURE ELNES; DENSITY THEORY; SPIN DYNAMICS; LOSS SPECTRA; K-EDGES AB We investigate the ability of the local density approximation (LDA) in density functional theory to predict the near-edge structure in electron energy-loss spectroscopy in the dipole approximation. We include screening of the core hole within the LDA using Slater's transition state theory. We find that anion K-edge threshold energies are systematically overestimated by 4.22 +/- 0.44 eV in twelve transition metal carbides and nitrides in the rock-salt (B1) structure. When we apply this 'universal' many-electron correction to energy-loss spectra calculated within the transition state approximation to LDA, we find quantitative agreement with experiment to within one or two eV for TiC, TiN and VN. We compare our calculations to a simpler approach using a projected Mulliken density which honours the dipole selection rule, in place of the dipole matrix element itself. We find remarkably close agreement between these two approaches. Finally, we show an anomaly in the near-edge structure in CrN to be due to magnetic structure. In particular, we find that the N K edge in fact probes the magnetic moments and alignments of ther sublattice. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Atomist Simulat Grp, Belfast BT7 1NN, Antrim, North Ireland. Sandia Natl Labs, Livermore, CA 94551 USA. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. RP Queens Univ Belfast, Dept Pure & Appl Phys, Atomist Simulat Grp, Belfast BT7 1NN, Antrim, North Ireland. OI Paxton, Anthony/0000-0003-4182-8210 NR 58 TC 59 Z9 59 U1 1 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD FEB 7 PY 2000 VL 12 IS 5 BP 729 EP 750 DI 10.1088/0953-8984/12/5/319 PG 22 WC Physics, Condensed Matter SC Physics GA 293AH UT WOS:000085829000022 ER PT J AU Borchi, E Bruzzi, M Li, Z Pirollo, S AF Borchi, E Bruzzi, M Li, Z Pirollo, S TI Thermally stimulated currents analysis of the shallow levels in irradiated silicon detectors SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID SEMICONDUCTORS; SPECTROSCOPY AB Thermally stimulated current measurements in the temperature range 10-20 K have been performed on a set of silicon p(+)/n/n(+) junction detectors. The samples were irradiated with fluences from 6.4 x 10(11) cm(-2) up to 1.1 x 10(14) cm(-2) (1 MeV neutron equivalent) in order to investigate the changes in the shallow level concentrations induced by irradiation. The measurements showed a broadening of the peak shape and a decrease in the height of the spectral components as the fluence increases. A phosphorus removal of approximately one order of magnitude is observed for the most irradiated sample, while the boron component is almost independent of the fluence. At the highest level of irradiation the phosphorus and boron levels show comparable concentrations. C1 Univ Florence, Dipartimento Energet, I-50139 Florence, Italy. INFM, I-50125 Florence, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Borchi, E (reprint author), Univ Florence, Dipartimento Energet, Via S Marta 3, I-50139 Florence, Italy. RI Bruzzi, Mara/K-1326-2015 OI Bruzzi, Mara/0000-0001-7344-8365 NR 18 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD FEB 7 PY 2000 VL 33 IS 3 BP 299 EP 304 DI 10.1088/0022-3727/33/3/318 PG 6 WC Physics, Applied SC Physics GA 288BD UT WOS:000085541200020 ER PT J AU Habib, S Lythe, G AF Habib, S Lythe, G TI Dynamics of kinks: Nucleation, diffusion, and annihilation SO PHYSICAL REVIEW LETTERS LA English DT Article ID OVERDAMPED SOLITON MOTION; SINE-GORDON SOLITONS; STATISTICAL-MECHANICS; ANTIKINK NUCLEATION; THERMAL NUCLEATION; LANGEVIN EQUATION; 1+1 DIMENSIONS; FIELD; MODEL; TEMPERATURES AB We investigate the nucleation, annihilation, and dynamics of kinks in a classical (1 + 1)-dimensional phi(4) field theory at finite temperature. From large scale Langevin simulations, we establish that the nucleation rate is proportional to the square of the equilibrium density of kinks. We identify two annihilation time scales: one due to kink-antikink pail recombination after nucleation, the other from nonrecombinant annihilation. We introduce a mesoscopic model of diffusing kinks based on "paired" and "survivor": kinks and antikinks. Analytical predictions for the dynamical time scales, as well as the corresponding length stales, are in good agreement with thr simulations. 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. RP Habib, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-8,MS B285, Los Alamos, NM 87545 USA. OI Lythe, Grant/0000-0001-7966-5571 NR 44 TC 36 Z9 36 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 7 PY 2000 VL 84 IS 6 BP 1070 EP 1073 DI 10.1103/PhysRevLett.84.1070 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500003 ER PT J AU Spayde, DT Averett, T Barkhuff, D Beck, DH Beise, EJ Benson, C Breuer, H Carr, R Covrig, S DelCorso, J Dodson, G Dow, K Eppstein, C Farkhondeh, M Filippone, BW Frazier, P Hasty, R Ito, TM Jones, CE Korsch, W Kowalski, S Lee, P Maneva, E McCarty, K McKeown, RD Mikell, J Mueller, B Naik, P Pitt, M Ritter, J Savu, V Sullivan, M Tieulent, R Tsentalovich, E Wells, SP Yang, B Zwart, T AF Spayde, DT Averett, T Barkhuff, D Beck, DH Beise, EJ Benson, C Breuer, H Carr, R Covrig, S DelCorso, J Dodson, G Dow, K Eppstein, C Farkhondeh, M Filippone, BW Frazier, P Hasty, R Ito, TM Jones, CE Korsch, W Kowalski, S Lee, P Maneva, E McCarty, K McKeown, RD Mikell, J Mueller, B Naik, P Pitt, M Ritter, J Savu, V Sullivan, M Tieulent, R Tsentalovich, E Wells, SP Yang, B Zwart, T TI Parity violation in elastic electron-proton scattering and the proton's strange magnetic form factor SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRAL-CURRENT; BREAKING; NUCLEON; MOMENT AB We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92 +/- 0.61 +/- 0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections. C1 CALTECH, Kellogg Radiat Lab, Pasadena, CA 91125 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. MIT, Bates Linear Accelerator Ctr, Nucl Sci Lab, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Louisiana Tech Univ, Dept Phys, Ruston, LA 71272 USA. RP Averett, T (reprint author), CALTECH, Kellogg Radiat Lab, Pasadena, CA 91125 USA. RI Maneva, Elitza/A-7890-2008; Savu, Veronica/C-6069-2009; Averett, Todd/A-2969-2011; Lee, Patricia/B-6146-2012; Maneva, Elitza/E-9215-2013; OI Maneva, Elitza/0000-0002-8638-1013; Sullivan, Matthew/0000-0003-4263-0273 NR 16 TC 126 Z9 128 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 FEB 7 PY 2000 VL 84 IS 6 BP 1106 EP 1109 DI 10.1103/PhysRevLett.84.1106 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500012 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, BS Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, A Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Cobal, M Cocca, E Connolly, A Conway, J Cooper, J Cordelli, M Costanzo, D Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, J Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Meschi, E Mesropian, C Miao, T Miller, JS Miller, R Minato, H Miscetti, S Mishina, M Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takashima, R Takikawa, K Tanaka, M Takano, T Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Vologouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Toshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, BS Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, A Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Cobal, M Cocca, E Connolly, A Conway, J Cooper, J Cordelli, M Costanzo, D Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, J Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Meschi, E Mesropian, C Miao, T Miller, JS Miller, R Minato, H Miscetti, S Mishina, M Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takashima, R Takikawa, K Tanaka, M Takano, T Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Vologouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Toshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S CA CDF Collaboration TI Search for color singlet technicolor particles in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID LOW-SCALE TECHNICOLOR; FERMILAB; TEVATRON; DETECTOR; PHYSICS AB We search for color singlet technirho and technipion production in p (p) over bar collisions at root s = 1.8 TeV recorded with the Collider Detector at Fennilab. These exotic technimesons are present in a model of walking technicolor. The signatures studied an lepton plus two jets plus E-T and multijet final states. No excess of events is seen in either final state. We set an upper limit on the technirho production cross section and exclude a region in the technipion mass versus technirho mass plane. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Cantabria, Inst Fis, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Nucl Res Inst, RU-141980 Dubna, Russia. Duke Univ, Durham, NC 27708 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kyungpook Natl Univ, Korean Hadron Collider Lab, Taegu 702701, South Korea. Seoul Natl Univ, Seoul 151742, South Korea. Sungkyunkwan Univ, Suwon 440746, South Korea. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 305, Japan. MIT, Cambridge, MA 02139 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, Ist Nazl Fis Nucl, Sezione Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Affolder, T (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Scodellaro, Luca/K-9091-2014; Paulini, Manfred/N-7794-2014; Prokoshin, Fedor/E-2795-2012; Introzzi, Gianluca/K-2497-2015; vilar, rocio/D-7454-2014 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Scodellaro, Luca/0000-0002-4974-8330; Paulini, Manfred/0000-0002-6714-5787; Prokoshin, Fedor/0000-0001-6389-5399; Introzzi, Gianluca/0000-0002-1314-2580; NR 14 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 FEB 7 PY 2000 VL 84 IS 6 BP 1110 EP 1115 DI 10.1103/PhysRevLett.84.1110 PG 6 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500013 ER PT J AU Turner, AM Turner, L AF Turner, AM Turner, L TI Manifestation of random phase in a finite ensemble of a turbulent fluid SO PHYSICAL REVIEW LETTERS LA English DT Article AB A field can be specified by a set of spectral coefficients, {c(j)(t)}, relative to an expansion basis. In fluid turbulence, one often assumes the condition that if one were to extract data from an ensemble of realizations, one would find that the average, [c(i)*(t)c(i')(t)], would vanish unless i = i', as in the case of a homogeneous ensemble in which the i's represent wave vectors. We analytically treat an extension to the case in which one has a larger number of coefficients than realizations introducing intrinsic linear dependences that vitiate the stated condition. C1 Princeton Univ, Princeton, NJ 08544 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Turner, AM (reprint author), Princeton Univ, Princeton, NJ 08544 USA. NR 12 TC 4 Z9 4 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 FEB 7 PY 2000 VL 84 IS 6 BP 1176 EP 1179 DI 10.1103/PhysRevLett.84.1176 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500029 ER PT J AU Bates, JW Montgomery, DC AF Bates, JW Montgomery, DC TI The D'yakov-Kontorovich instability of shock waves in real gases SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLUX-CORRECTED TRANSPORT; STABILITY; EMISSION AB In the 1950s, D'yakov and Kontorovich predicted that under certain conditions perturbed shock waves in nonideal gases can become unstable by emitting undamped sound and entropy-vortex waves. For the last 45 years, though, little progress has been made in the identification and numerical modeling of physical conditions for which this phenomenon might occur. Using a van der Waals equation of state, we present for the first time a dynamical simulation of a D'yakov-Kontorovich instability. The two-dimensional emission pattern of acoustic waves appearing in the simulation agrees with the prediction of a linearized theory. C1 Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. RP Los Alamos Natl Lab, Div Appl Phys, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 23 Z9 23 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 7 PY 2000 VL 84 IS 6 BP 1180 EP 1183 DI 10.1103/PhysRevLett.84.1180 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500030 ER PT J AU Bai, M Allgower, C Ahrens, L Alessi, J Brown, K Bunce, G Cameron, P Chu, CM Courant, ED Glenn, JW Huang, H Jeon, D Kponou, AE Krueger, K Luccio, A Makdisi, YI Lee, SY Ratner, L Reece, K Roser, T Spinka, H Syphers, MJ Tsoupas, N Underwood, DG van Asselt, W Williams, N Yokosawa, A AF Bai, M Allgower, C Ahrens, L Alessi, J Brown, K Bunce, G Cameron, P Chu, CM Courant, ED Glenn, JW Huang, H Jeon, D Kponou, AE Krueger, K Luccio, A Makdisi, YI Lee, SY Ratner, L Reece, K Roser, T Spinka, H Syphers, MJ Tsoupas, N Underwood, DG van Asselt, W Williams, N Yokosawa, A TI Observation of a hybrid spin resonance SO PHYSICAL REVIEW LETTERS LA English DT Article ID POLARIZATION; ACCELERATION; BEAM AB A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchroton (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors. C1 Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Bai, M (reprint author), Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. RI Jeon, Dong-O/S-2137-2016 OI Jeon, Dong-O/0000-0001-6482-5878 NR 13 TC 5 Z9 5 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 FEB 7 PY 2000 VL 84 IS 6 BP 1184 EP 1187 DI 10.1103/PhysRevLett.84.1184 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500031 ER PT J AU Lefevre, T Gardelle, J Rullier, JL Vermare, C Donohue, JT Meurdesoif, Y Lidia, SM AF Lefevre, T Gardelle, J Rullier, JL Vermare, C Donohue, JT Meurdesoif, Y Lidia, SM TI Free-electron laser as a driver for a resonant cavity at 35 GHz SO PHYSICAL REVIEW LETTERS LA English DT Article ID KLYSTRON 2-BEAM ACCELERATOR AB An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity. C1 CEA, CESTA, F-33114 Le Barp, France. CEN Bordeaux Gradignan, F-33175 Gradignan, France. Univ Bordeaux 1, Ctr Phys Theor & Modelisat, F-33405 Talence, France. EO Lawrence Berkeley Natl Lab MS, Ctr Beam Phys, Berkeley, CA 94720 USA. RP Lefevre, T (reprint author), CEA, CESTA, BP 2, F-33114 Le Barp, France. NR 14 TC 4 Z9 4 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 FEB 7 PY 2000 VL 84 IS 6 BP 1188 EP 1191 DI 10.1103/PhysRevLett.84.1188 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500032 ER PT J AU Bernabei, S Bell, MG Budny, RV Fredrickson, ED Gorelenkov, NN Hosea, JC Majeski, R Mazzucato, E Phillips, CK Schilling, G Wilson, JR AF Bernabei, S Bell, MG Budny, RV Fredrickson, ED Gorelenkov, NN Hosea, JC Majeski, R Mazzucato, E Phillips, CK Schilling, G Wilson, JR TI Nature of monster sawteeth and their relationship to Alfven instabilities in tokamaks SO PHYSICAL REVIEW LETTERS LA English DT Article ID EIGENMODES; TFTR; PLASMAS AB A correlation is explored between the presence of energetic particle modes (EPM) and long-period sawtooth oscillations in tokamak plasmas heated by rf waves. The eventual crash of these sawteeth is explained in terms of the loss of the stabilizing fast particles due to the EPM. The absence of long-period sawteeth in high q(a) discharges is explained in terms of ion loss due to toroidal Alfven eigenmodes. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. TRINITI, Troitsk 142092, Russia. RP Bernabei, S (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 13 TC 25 Z9 25 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 FEB 7 PY 2000 VL 84 IS 6 BP 1212 EP 1215 DI 10.1103/PhysRevLett.84.1212 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500038 ER PT J AU Zhang, SB Wei, SH Zunger, A AF Zhang, SB Wei, SH Zunger, A TI Microscopic origin of the phenomenological equilibrium "doping limit rule'' in n-type III-V semiconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID BAND; ENERGIES; CENTERS; DONOR; GAAS; GAS AB The highest equilibrium free-carrier doping concentration possible in a given material is limited by the "pinning energy" which shows a remarkable universal alignment in each class of semiconductors. Our first-principles total energy calculations reveal that equilibrium n-type doping is ultimately limited by the spontaneous formation of close-shell acceptor defects: the (3-)-charged cation vacancy in AlN, GaN, InP, and GaAs and the (1-)-charged DX center in AlAs, AlP, and GaP. This explains the alignment of the pinning energies and predicts the maximum equilibrium doping levels in different materials. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 23 TC 123 Z9 125 U1 4 U2 33 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 FEB 7 PY 2000 VL 84 IS 6 BP 1232 EP 1235 DI 10.1103/PhysRevLett.84.1232 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500043 ER PT J AU Vekhter, I Bulaevskii, LN Koshelev, AE Maley, MP AF Vekhter, I Bulaevskii, LN Koshelev, AE Maley, MP TI Interlayer quasiparticle transport in the vortex state of Josephson coupled superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC-FIELD DEPENDENCE; D-WAVE SUPERCONDUCTOR; THERMAL-CONDUCTIVITY; BI2SR2CACU2O8+DELTA; JUNCTIONS; PHASE; RESISTANCE; PARAMETER; CRYSTALS; HEAT AB We calculate the dependence of the interlayer quasiparticle conductivity, sigma(q), in a Josephson coupled d-wave superconductor on the magnetic field B parallel to c and the temperature T. We consider a clean superconductor with resonant impurity scattering and a dominant coherent interlayer tunneling. When pancake vortices in adjacent layers are weakly correlated, at low T the conductivity increases sharply with B over a field scale determined by the impurity scattering, before reaching an extended region of slow linear growth. At high T the conductivity initially decreases and then reaches the same linear regime. For correlated pancakes, sigma(q) increases much more strongly with the applied field. C1 Univ Guelph, Dept Phys, Guelph, ON N1G 2W1, Canada. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Vekhter, I (reprint author), Univ Guelph, Dept Phys, Guelph, ON N1G 2W1, Canada. RI Vekhter, Ilya/M-1780-2013; Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 36 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 7 PY 2000 VL 84 IS 6 BP 1296 EP 1299 DI 10.1103/PhysRevLett.84.1296 PG 4 WC Physics, Multidisciplinary SC Physics GA 281UE UT WOS:000085178500059 ER PT J AU Dawson, SP D'Angelo, MV Pearson, JE AF Dawson, SP D'Angelo, MV Pearson, JE TI Towards a global classification of excitable reaction-diffusion systems SO PHYSICS LETTERS A LA English DT Article ID SELF-REPLICATING SPOTS; PATTERN-FORMATION; LANDOLT REACTION; MODEL; FERROCYANIDE AB Patterns in reaction-diffusion systems near primary bifurcations can be studied locally and classified by means of amplitude equations. This is not possible for excitable reaction-diffusion systems. In this paper we propose a global classification of two variable excitable reaction-diffusion systems. In particular, we claim that the topology of the underlying two-dimensional homogeneous dynamics organizes the system's behavior. We believe that this classification provides a useful tool for the modeling of any real system whose microscopic details are unknown. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis, RA-1428 Buenos Aires, DF, Argentina. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Dawson, SP (reprint author), Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis, Ciudad Univ,Pabellon 1, RA-1428 Buenos Aires, DF, Argentina. OI Ponce Dawson, Silvina/0000-0001-6550-4267 NR 20 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD FEB 7 PY 2000 VL 265 IS 5-6 BP 346 EP 352 DI 10.1016/S0375-9601(00)00008-6 PG 7 WC Physics, Multidisciplinary SC Physics GA 284DE UT WOS:000085314800005 ER PT J AU Selby, PB AF Selby, PB TI Stillbirths among offspring of male radiation workers SO LANCET LA English DT Letter ID MICE C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. RP Selby, PB (reprint author), Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU LANCET LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0140-6736 J9 LANCET JI Lancet PD FEB 5 PY 2000 VL 355 IS 9202 BP 492 EP 493 DI 10.1016/S0140-6736(00)82042-5 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA 283ZW UT WOS:000085306800042 PM 10841147 ER PT J AU Ahmed, M Peterka, DS Suits, AG AF Ahmed, M Peterka, DS Suits, AG TI H abstraction dynamics by crossed-beam velocity map imaging: Cl+CH3OH -> CH2OH+HCl SO CHEMICAL PHYSICS LETTERS LA English DT Article ID HYDROGEN ABSTRACTION; SYNCHROTRON-RADIATION; OXALYL CHLORIDE; ATOMS; PHOTODISSOCIATION; KINETICS; METHANOL AB The crossed-beam reaction of ground state Cl (P-2(3/2)) atoms with CH3OH have been studied using the technique of velocity map imaging (VELMI). The hydroxymethyl (CH2OH) radical was detected via single-photon ionization using 157 nm laser light. The full double-differential cross-sections were obtained at a collision energy of 8.7 kcal/mol. The angular distribution was predominantly in the sideways-backward direction with respect to the incoming alcohol beam suggesting direct abstraction dynamics. The average translational energy release was 6.1 kcal/mol, out of 15.1 kcal/mol available. The technique of vacuum ultraviolet one-photon ionization in conjunction with VELMI promises to be useful for studying the reaction dynamics for many polyatomic systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Suits, AG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Ahmed, Musahid/A-8733-2009 NR 21 TC 36 Z9 36 U1 0 U2 7 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 FEB 4 PY 2000 VL 317 IS 3-5 BP 264 EP 268 DI 10.1016/S0009-2614(99)01406-2 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 282PT UT WOS:000085227800013 ER PT J AU Parra, M Gascard, P Walensky, LD Gimm, JA Blackshaw, S Chan, N Takakuwa, Y Berger, T Lee, G Chasis, JA Snyder, SH Mohandas, N Conboy, JG AF Parra, M Gascard, P Walensky, LD Gimm, JA Blackshaw, S Chan, N Takakuwa, Y Berger, T Lee, G Chasis, JA Snyder, SH Mohandas, N Conboy, JG TI Molecular and functional characterization of protein 4.1B, a novel member of the protein 4.1 family with high level, focal expression in brain SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID PRE-MESSENGER-RNA; MEMBRANE SKELETAL PROTEIN-4.1; SPECTRIN-ACTIN-BINDING; ERYTHROCYTE PROTEIN-4.1; STRUCTURAL PROTEIN-4.1; 4.1-BINDING SITE; TERNARY COMPLEX; GLYCOPHORIN-C; CELL-BODIES; DOMAIN AB Brain-enriched isoforms of skeletal proteins in the spectrin and ankyrin gene families have been described. Here we characterize protein 4.1B, a novel homolog of erythrocyte protein 4.1R that is encoded by a distinct gene. In situ hybridization revealed high level, focal expression of 4.1B mRNA in select neuronal populations within the mouse brain, including Purkinje cells of the cerebellum, pyramidal cells in hippocampal regions CA1-3, thalamic nuclei, and olfactory bulb. Expression was also detected in adrenal gland, kidney, testis, and heart. 4.1B protein exhibits high homology to the membrane binding, spectrin-actin binding, and C-terminal domains of 4.1R, including motifs for interaction with NuMA and FKBP13, cDNA characterization and Western blot analysis revealed multiple spliceoforms of protein 4.1B, with functionally relevant heterogeneity in the spectrin-actin and NuMA binding domains. Regulated alternative splicing events led to expression of unique 4.1B isoforms in brain and muscle; only the latter possessed a functional spectrin-actin binding domain. By immunofluorescence, 4.1B was localized specifically at the plasma membrane in regions of cell-cell contact. Together these results indicate that 4.1B transcription is selectively regulated among neuronal populations and that alternative splicing regulates expression of 4.1B isoforms possessing critical functional domains typical of other protein 4.1 family members. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Johns Hopkins Univ, Sch Med, Dept Neurosci, Baltimore, MD 21205 USA. Tokyo Womens Med Univ, Sch Med, Dept Biochem, Tokyo 162, Japan. Univ Calif Davis, Dept Anim Sci, Davis, CA 95616 USA. RP Conboy, JG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, MS 74-174, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL45182]; NIDDK NIH HHS [DK32094, P01 DK032094]; NIMH NIH HHS [MH18501] NR 56 TC 88 Z9 95 U1 0 U2 1 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 FEB 4 PY 2000 VL 275 IS 5 BP 3247 EP 3255 DI 10.1074/jbc.275.5.3247 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 281FD UT WOS:000085146500033 PM 10652311 ER PT J AU Rudisser, S Tinoco, I AF Rudisser, S Tinoco, I TI Solution structure of cobalt(III)hexammine complexed to the GAAA tetraloop, and metal-ion binding to G center dot A mismatches SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA structure; NMR; metal-ion binding; group I intron; P5abc ID RELAXATION MATRIX APPROACH; RESPONSIVE ELEMENT RNA; CRYSTAL-STRUCTURE; NMR-SPECTROSCOPY; HAMMERHEAD RIBOZYME; HYDROGEN-BONDS; RIBOSOMAL-RNA; MAJOR GROOVE; REV PEPTIDE; BASE-PAIRS AB The solution structure of a 22 nt RNA hairpin and its complex with Co(NH3)(6)(3+) bound to the GAAA tetraloop has been determined by NMR spectroscopy. Co(NH3)(6)(3+) has a similar geometry to Mg(H2O)(6)(2+) and can be used as a probe for binding sites of completely solvated magnesium ions. The hairpin contains tandem G.A mismatches, similar to the P5abc region of a group I intron, and is closed by a GAAA tetraloop. The tandem G A mismatches are imino hydrogen bonded in contrast with the sheared G A mismatches found in a different context in the crystal structure of the P4-P6 domain. Chemical shift changes of the imino protons upon titration of the RNA hairpin with Mg2+ and with Co(NH3)(6)(3+) were used to identify ion-binding sites. Paramagnetic resonance broadening upon titration with Mn2+ was also used. The titration curves gave dissociation binding constants for the magnesium ions in the millimolar range, similar to the binding in the major groove of RNA at tandem G.U base-pairs. Although the largest chemical shift change occurred at an imino proton of one of the G A base-pairs, no nuclear Overhauser enhancement cross-peaks between the cobalt ligand and neighboring RNA protons were seen, presumably due to the high mobility of the Co(NH3)(6)(3+) at this site. Nuclear Overhauser enhancement cross-peaks between Co(NH3)(6)(3+) and the GAAA tetraloop were observed, which allowed the determination of the structure of the tetraloop binding site. The Co(NH3)(6)(3+) is bound in the major groove of the GAAA tetraloop with hydrogen bonds to guanine base N7 and to phosphate oxygen atoms of the tetraloop. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Tinoco, I (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM 10840] NR 80 TC 86 Z9 89 U1 0 U2 6 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 4 PY 2000 VL 295 IS 5 BP 1211 EP 1223 DI 10.1006/jmbi.1999.3421 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 281NJ UT WOS:000085167000010 PM 10653698 ER PT J AU Yonker, CR AF Yonker, CR TI Solution dynamics of perfluorobenzene, benzene, and perdeuteriobenzene in carbon dioxide as a function of pressure and temperature SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR MODELING APPROACH; SELF-DIFFUSION; LIQUID; ETHANE; NMR; HEXAFLUOROETHANE AB The F-19, H-1, and H-2 relaxation times of perfluorobenzene, benzene, and perdeuteriobenzene were measured in carbon dioxide using capillary high-pressure NMR spectroscopy. The pressure range for the measurement of the F-19, H-1, and H-2 nuclear relaxation times was between 400 and 2300 atm over a temperature range of 298-423 K, The density regime of the solvent, carbon dioxide, over these conditions was between 0.55 and 1.27 g/cm(3). Over this wide range of solvent conditions, the contributions to the molecular relaxation processes for both H-1 and F-19 in CO2 were determined. These conditions were chosen to address the occurrence of specific molecular interactions between CO2 and fluorine. From the comparison of the relaxation processes for F-19 and H-1 in CO2, especially at high densities, any interaction between fluorine and carbon dioxide should be prevalent. No specific interaction between fluorine and CO2 contributing to the molecular relaxation of these nuclei was noted over the temperature and pressure range investigated in this study. C1 Pacific NW Natl Lab, Environm & Energy Sci Div, Richland, WA 99352 USA. RP Yonker, CR (reprint author), Pacific NW Natl Lab, Environm & Energy Sci Div, Richland, WA 99352 USA. NR 18 TC 31 Z9 31 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 3 PY 2000 VL 104 IS 4 BP 685 EP 691 DI 10.1021/jp992725z PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 280WF UT WOS:000085126200002 ER PT J AU Ratsep, M Johnson, TW Chitnis, PR Small, GJ AF Ratsep, M Johnson, TW Chitnis, PR Small, GJ TI The red-absorbing chlorophyll a antenna states of photosystem I: A hole-burning study of Synechocystis sp PCC 6803 and its mutants SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID RHODOPSEUDOMONAS-ACIDOPHILA STRAIN-10050; PHOTOSYNTHETIC REACTION CENTERS; LIGHT-HARVESTING ANTENNAS; PRIMARY CHARGE SEPARATION; ENERGY-TRANSFER DYNAMICS; EXCITON LEVEL STRUCTURE; ELECTRON-DONOR STATE; PURPLE BACTERIA; HIGH-PRESSURE; SYNECHOCOCCUS-ELONGATUS AB Low temperature (4.2 K) absorption and hole-burned spectra are presented for the trimeric (wild-type, WT) photosystem I complex of the cyanobacterium Synechocystis sp. PCC 6803, its monomeric form, and mutants deficient in the PsaF, K, L, and M protein subunits. High-pressure- and Stark-hole-burning data for the WT trimer are presented as well as its temperature-dependent Q(nu)-absorption and -fluorescence spectra. Taken as a whole, the data lead to assignment: of a new and lowest energy antenna Q(y)-state, located at 714 nm at low temperatures. It is this state that is responsible for the fluorescence in the low-temperature limit and not the previously identified antenna Q(y)-state near 708 nm. The data indicate that the 714 nm state is associated with strongly coupled chlorophyll a molecules (perhaps a dimer) and possesses significant charge transfer character. The red chlorophylls absorbing at 708 and 714 nm do not appear to be directly bound to any of the above protein subunits. The results are consistent with a location close to the interfacial regions between PsaL and M and the PsaA/B heterodimeric core. It is likely that the red chlorophylls are bound to PsaA and/or PsaB. C1 Iowa State Univ Sci & Technol, Ames Lab, US Dept Energy, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Biochem Biophys & Mol Biol, Ames, IA 50011 USA. RP Small, GJ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, US Dept Energy, Ames, IA 50011 USA. NR 52 TC 86 Z9 89 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD FEB 3 PY 2000 VL 104 IS 4 BP 836 EP 847 DI 10.1021/jp9929418 PG 12 WC Chemistry, Physical SC Chemistry GA 280TW UT WOS:000085120700028 ER PT J AU Phillips, DR Rupak, G Savage, MJ AF Phillips, DR Rupak, G Savage, MJ TI Improving the convergence of NN effective field theory SO PHYSICS LETTERS B LA English DT Article ID NUCLEON-NUCLEON-SCATTERING; CHIRAL LAGRANGIANS; DEUTERON SCATTERING; RANGE INTERACTIONS; 2-NUCLEON SYSTEMS; FORCES; REGULARIZATION; RENORMALIZATION; MESON AB We study a low-energy effective field theory (EFT) describing the NN system in which all exchanged particles are integrated out. We show that fitting the residue of the S-3(1) amplitude at the deuteron pole, rather than the S-3(1) effective range, dramatically improves the convergence of deuteron observables in this theory. Reproducing the residue ensures that the tail of the deuteron wave function, which is directly related to NN scattering data via analytic continuation, is correctly reproduced in the EFT at next-to-leading order. The role of multi-nucleon-electroweak operators which produce deviations from effective-range theory can then be explicitly separated from the physics of the wave function tail. Such an operator contributes to the deuteron quadrupole moment, mu(Q), at low order, indicating a sensitivity to short-distance physics. This is consistent with the failure of impulse-approximation calculations in NN potential models to reproduce mu(Q). The convergence of NN phase shifts in the EFT is unimpaired by the use of this new expansion. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Phillips, DR (reprint author), Univ Washington, Dept Phys, Seattle, WA 98195 USA. NR 68 TC 75 Z9 75 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 3 PY 2000 VL 473 IS 3-4 BP 209 EP 218 DI 10.1016/S0370-2693(99)01496-3 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 283QJ UT WOS:000085286200003 ER PT J AU Gross, KJ Guthrie, S Takara, S Thomas, G AF Gross, KJ Guthrie, S Takara, S Thomas, G TI In-situ X-ray diffraction study of the decomposition of NaAlH4 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE metal hydrides; X-ray diffraction; NaAlH4; Na3AlH6; Rietveld refinement ID PHASE AB Phase transitions and crystal structure modifications were observed during the thermal-desorption decomposition of the alanate NaAlH4. This was accomplished through the use of in-situ X-ray powder diffraction. A sequence of theta-2 theta scans were collected while heating the sample under a vacuum. The resulting diffraction patterns were assembled to provide a real-time representation of the decomposition reactions. It was found that upon heating, NaAlH4 initially experienced a lattice expansion principally in the c-axis direction. This was followed by continuous structural distortions observed as erratic variations in the Bragg intensities. Melting of NaAlH4 was observed at 180 degrees C followed by the rapid precipitation of a cubic Na3AlHx phase. This phase then underwent a slow transformation into a Na-rich cubic phase. The decomposition of NaAlH4 doped with a double catalyst (Ti + Zr) was also investigated. The uncatalyzed sample showed no decomposition when held under a vacuum at 150 degrees C for several hours. The catalyzed sample, on the other hand, began to decompose readily into the monoclinic (alpha)-Na3AlH6 phase when heated to 100 degrees C in vacuum. At 150 degrees C the (alpha)-Na3AlH6 phase decomposed in a second reaction according to alpha-Na3AlH6->3 NaH + Al + 3/2 H-2. The two decomposition reactions appear to be interdependent as the second transformation commenced only after the first reaction neared completion. The observed growth of a narrow Al (111) diffraction peak indicates the formation of aluminum crystallites (>100 nm) as a part of the decomposition reactions. This, and the fact that this solid state process is assisted through the interaction of a surface catalyst suggests long-range transport of a metal species. Some mechanisms are proposed to explain the catalytically enhanced kinetics of these materials. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Univ Hawaii, Dept Chem, Honolulu, HI 96822 USA. RP Gross, KJ (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. RI Takara, Satoshi/A-1484-2011 NR 28 TC 214 Z9 216 U1 1 U2 31 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD FEB 2 PY 2000 VL 297 IS 1-2 BP 270 EP 281 DI 10.1016/S0925-8388(99)00598-8 PG 12 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 270AJ UT WOS:000084513000045 ER PT J AU Levitskaia, TG Bryan, JC Sachleben, RA Lamb, JD Moyer, BA AF Levitskaia, TG Bryan, JC Sachleben, RA Lamb, JD Moyer, BA TI A surprising host-guest relationship between 1,2-dichloroethane and the cesium complex of tetrabenzo-24-crown-8 SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ALKALI-METAL CATIONS; CROWN-ETHERS; COORDINATION CHEMISTRY; PARTITION-COEFFICIENTS; SOLVENT-EXTRACTION; MOLECULAR-DYNAMICS; ION SELECTIVITY; FREE-ENERGY; ANIONS; PARAMETERS AB The structure of the complex [Cs(tetrabenzo-24-crown-8)(1,2-dichloroethane)(2)](NO3). H2O was shown by X-ray crystallography to involve an unprecedented bidentate coordination of two 1,2-dichloroethane solvent molecules to the Cs+ cation via the four chlorine atoms. The coordination of the solvent molecules occurs within two clefts between facing benzo groups, one pair of benzo groups related to the other pair by an improper noncrystallographic 90 degrees rotation. Resembling the seam on a tennis ball, the crown ether envelops the metal cation within a cagelike arrangement of eight crown ether oxygen atoms. Good geometric and electronic complementarity characterizes the apparent host-guest relationship between the cleft environment and the solvent molecules. The complete encapsulation of the cation by the crown ether and two solvent molecules explains well the speciation behavior observed in liquid-liquid extraction of CsNO3 or CsClO4 from aqueous solution to 1,2-dichloroethane solutions of the alkylated analogues 4,4 "- or 4,5 "-bis(tert-octylbenzo)dibenzo-24-crown-8. In the extraction process studied at 25 degrees C, simple 1:1 metal/crown complexes form in the solvent phase, as modeled by the program SXLSQI. The complex cation and counteranion an present both as ion-pairs, postulated to be ligand-separated ion-pairs as suggested by the crystal structure, and as dissociated ions. In agreement with a theoretical treatment of ion-pairing the ion-pairs possess unusually low stability and exhibit no discrimination between the anions, largely ascribed to the large effective radius of the complex metal cation. Values of log K-f corresponding to the formation of the complex cations Cs[bis(tert-octylbenzo)dibenzo-24-crown-8](+) in 1,2-dichloroethane at 25 degrees C average 10.5 +/- 0.2 for both positional isomers of the crown ether and for their 3:2 mixture. Overall, these results provide insight into the role of clefts as host environments for inclusion of neutral molecules and show how even solvent molecules with exceptionally a weak donor-acceptor properties may participate in supramolecular assemblies. In addition, the results are unique in enabling a clear assessment of the effect of the encapsulation of the metal cation on the ion-pairing tendency of the metal complex and implications for anion selectivity. C1 Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. RP Moyer, BA (reprint author), Oak Ridge Natl Lab, Chem & Analyt Sci Div, POB 2008, Oak Ridge, TN 37831 USA. RI Solominow, Sonia/A-4021-2008; Moyer, Bruce/L-2744-2016 OI Moyer, Bruce/0000-0001-7484-6277 NR 86 TC 36 Z9 36 U1 4 U2 15 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 FEB 2 PY 2000 VL 122 IS 4 BP 554 EP 562 DI 10.1021/ja992760j PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 281MU UT WOS:000085165200002 ER PT J AU Grossman, JC Lester, WA Louie, SG AF Grossman, JC Lester, WA Louie, SG TI Quantum Monte Carlo and density functional theory characterization of 2-cyclopentenone and 3-cyclopentenone formation from O(P-3) plus cyclopentadiene SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CROSSED MOLECULAR-BEAM; STRUCTURAL-PROPERTIES; GAUSSIAN-2 THEORY; EXACT EXCHANGE; BASIS-SETS; ATOMS; ENERGIES; STATE; THERMOCHEMISTRY; O(3P)+C2H4 AB We investigate reaction paths for the formation of ground-state 2-cyclopentenone and 3-cyclopentenone arising from the electrophilic addition of O(P-3) to a double bond of cyclopentadiene. Our calculations show that one possible mechanism for these reactions is the formation initially of a triplet diradical that undergoes intersystem crossing to a diradical singlet followed by passage of the system through the transition state to ground-state products. Equilibrium geometries and total energies are computed for all species using the Hartree-Fock method, the local spin density approximation, four generalized gradient approximations, the G2 model chemistry method, and the quantum Monte Carlo (QMC) approach in both the variational (VMC) and diffusion (DMC) variants. Using DMC as a gauge of accuracy, a comparison of these approaches reveals that the density functional methods show mixed performance, with the gradient-corrected B3PW91 functional giving the best reaction pathway energetics overall for the group. The G2 energetics are in good agreement with DMC for stable species but differ significantly for transition states. A resonance found in precursors to formation of 3-cyclopentenone (3CP) provides a possible explanation for the appearance of 3CP in trace amounts in cyclopentadiene combustion reactors. C1 Lawrence Berkeley Lab, Div Chem Sci, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Lawrence Berkeley Lab, Div Chem Sci, Div Chem Sci, Berkeley, CA 94720 USA. NR 46 TC 13 Z9 13 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 2 PY 2000 VL 122 IS 4 BP 705 EP 711 DI 10.1021/ja983879f PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 281MU UT WOS:000085165200021 ER PT J AU Ge, NH Wong, CM Harris, CB AF Ge, NH Wong, CM Harris, CB TI Femtosecond studies of electron dynamics at interfaces SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID TIME-RESOLVED PHOTOEMISSION; SMALL POLARONS; SURFACES; STATES; LOCALIZATION; SPECTROSCOPY; CRYSTALS; AG(111) AB A delocalized electron at a metal-dielectric interface interacts with the adlayer and spatially localizes or self-traps on the femtosecond time scale into what is termed a small polaron. The dynamics can be studied by two-photon photoemission. Theoretical and experimental analyses reveal the interaction energy and the lattice vibrational mode that mediates electron localization. These results contribute to a fundamental understanding of electron behavior in weakly bonded solids and can lead to a better understanding of carrier dynamics in many different systems, including organic light-emitting diodes. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Harris, CB (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 41 TC 49 Z9 49 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD FEB PY 2000 VL 33 IS 2 BP 111 EP 118 DI 10.1021/ar980138a PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA 286CA UT WOS:000085425000006 PM 10673319 ER PT J AU Han, BG Nunomura, W Wu, HY Mohandas, N Jap, BK AF Han, BG Nunomura, W Wu, HY Mohandas, N Jap, BK TI Crystallization and preliminary X-ray crystallographic analysis of the 30 kDa membrane-binding domain of protein 4.1 from human erythrocytes SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID GLYCOPHORIN-C; CALMODULIN; SPECTRIN; SITE AB The 30 kDa membrane-binding domain of protein 4.1 from human erythrocytes has been expressed in Escherichia coli and crystallized in a form suitable for X-ray crystallographic study. Crystals were grown using a salting-in technique. Crystals have a tetragonal plate shape and belong to the C2 space group, with unit-cell parameters a = 163.9, b = 106.5, c = 93.5 Angstrom, beta = 95.5 degrees. The crystals diffract to 2.8 Angstrom resolution. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Jap, BK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RI Han, Bong-Gyoon/J-9120-2012 FU NIDDK NIH HHS [DK32094] NR 10 TC 7 Z9 7 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 FEB PY 2000 VL 56 BP 187 EP 188 DI 10.1107/S090744499901495X PN 2 PG 2 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 288HX UT WOS:000085557600010 PM 10666600 ER PT J AU Khlebtsova, N Hung, LW Henderson, K Moon, R Earnest, T AF Khlebtsova, N Hung, LW Henderson, K Moon, R Earnest, T TI Expression, crystallization and preliminary X-ray studies of the PDZ domain of Dishevelled protein SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID SIGNALING PATHWAYS; RECOGNITION; DROSOPHILA; POLARITY AB Dishevelled (Dsh) protein is an important component of the Wnt signal-transduction pathway. It has three relatively conserved domains: DIX, PDZ and DEP. The PDZ domain of the Xenopus laevis homolog of Dsh, which consists of residues 254-348, was overexpressed as a soluble protein in Escherichia coli, purified and crystallized. The crystals were obtained by the vapor-diffusion method, using 1.4 M sodium formate as a precipitant. The crystals diffracted to 2.3 Angstrom resolution. The space group was determined to be P6(1)22 or P6(5)22, with unit-cell dimensions a = b = 95.9, c = 93.9 Angstrom. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Macromol Crystallog Facil,Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Biophys Grp, Berkeley, CA 94720 USA. Univ Washington, Sch Med, Howard Hughes Med Inst, Seattle, WA 98195 USA. Univ Washington, Sch Med, Dept Pharmacol, Seattle, WA 98195 USA. RP Earnest, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Macromol Crystallog Facil,Phys Biosci Div, MS 6-2100, Berkeley, CA 94720 USA. RI Moon, Randall/B-1743-2014 OI Moon, Randall/0000-0002-9352-1408 NR 16 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 FEB PY 2000 VL 56 BP 212 EP 214 DI 10.1107/S0907444999016054 PN 2 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 288HX UT WOS:000085557600019 PM 10666609 ER PT J AU Russell, AM Chumbley, LS Tian, Y AF Russell, AM Chumbley, LS Tian, Y TI Deformation processed metal-metal composites SO ADVANCED ENGINEERING MATERIALS LA English DT Review ID IN-SITU COMPOSITES; CU-NB COMPOSITE; HIGH-STRENGTH; MECHANICAL-PROPERTIES; INTERPHASE BARRIER; INSITU COMPOSITES; YIELD STRENGTH; ALLOYS; MICROSTRUCTURE; WIRES AB Deformation processed metal-metal composites (DMMCs) are composites in which both the matrix and the reinforcing phase are ductile metals. The ductility of the metals permits the composite to be heavily deformed by drawing or rolling to reduce the thickness and spacing of the two phases to as small as 10 nm. Their nano-scale microstructures are exceptionally strong, with strengths approaching whisker strength in some cases. And since the materials are comprised of two essentially pure metals, their electrical conductivities are quite high for current flow in directions parallel to the composite's filaments or lamellae, leading to numerous potential applications. During the 1990s, continuing research has produced DMMCs in a wide range of matrix metals, including Al, Au, Mg, Sc, and Ti. Methods are also being developed to produce DMMCs with much larger dimensions in rod and sheet forms to permit their use in a wider variety of engineering applications. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Russell, AM (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 3053 Gilman Hall, Ames, IA 50011 USA. OI Russell, Alan/0000-0001-5264-0104 NR 66 TC 33 Z9 34 U1 0 U2 17 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 1438-1656 J9 ADV ENG MATER JI Adv. Eng. Mater. PD FEB PY 2000 VL 2 IS 1-2 BP 11 EP 22 DI 10.1002/(SICI)1527-2648(200002)2:1/2<11::AID-ADEM11>3.0.CO;2-Z PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 357JN UT WOS:000089494900009 ER PT J AU Miller, CF Hatcher, RD Ayers, JC Coath, CD Harrison, TM AF Miller, CF Hatcher, RD Ayers, JC Coath, CD Harrison, TM TI Age and zircon inheritance of eastern Blue Ridge plutons, southwestern North Carolina and northeastern Georgia,with implications for magma history and evolution of the southern Appalachian orogen SO AMERICAN JOURNAL OF SCIENCE LA English DT Article ID U-PB AGES; CONTINENTAL-CRUST; SUSPECT TERRANES; NEW-BRUNSWICK; COMPLEX; MELTS; CATHODOLUMINESCENCE; GEOCHRONOLOGY; METAMORPHISM; TEMPERATURE AB High-resolution ion microprobe analysis of zircon has provided ages for previously undated plutons of the high-grade eastern Blue Ridge of northeastern Georgia and southwestern North Carolina. These data, together with backscattered electron imaging, reveal the presence of nearly ubiquitous inherited cores of highly variable age and magmatic rims that have experienced variable Pb loss, thus making interpretation of conventional U-Pb analyses very difficult. Ion probe rim analyses indicate that the plutons were emplaced during both the mid-Ordovician (Taconian orogeny; Whiteside pluton, 465 Ma; Persimmon Creek Gneiss, 480 Ma) and mid-Devonian (Acadian orogeny; Rabun pluton, 375 Ma; Pink Beds pluton, 390 Ma;Looking Glass pluton, 380 Ma). A large trondhjemite dike north of Asheville is less confidently assigned an ape of 415 Ma. Zircons from all intrusions have predominantly 1.0 to 1.25 Ga cores (Grenvillian). In addition, both Devonian and Ordovician plutons have smaller populations of Late Proterozoic-early Paleozoic (0.5-0.75 Ga), Middle Proterozoic (1.4 Ga), and Late Archean (2.6-2.9 Ga) cores. The ubiquitous, round cores and thick magmatic rims suggest significant resorption and then protracted growth within the melts. Zircon saturation temperatures based on whole-rock (similar to melt) Zr concentrations are lower than expected for magma generation (710 degrees-760 degrees C). Zirconium concentrations may not reflect saturation at maximum temperature, if melting was very rapid ( 3. We find a large population of objects of intermediate radio loudness; there is no evidence in our sample for a bimodal distribution of radio characteristics. The sample includes similar to 29 broad absorption line quasars, both high and low ionization, and a number of new objects with remarkable optical spectra. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. WM Keck Observ, Kamuela, HI 96743 USA. Univ Chicago, Ctr Astron & Astrophys, Chicago, IL 60637 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. RP White, RL (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM rlw@stsci.edu RI Oegerle, William/C-9070-2012 NR 39 TC 253 Z9 254 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2000 VL 126 IS 2 BP 133 EP 207 DI 10.1086/313300 PG 75 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 308VA UT WOS:000086732500001 ER PT J AU Martinez-Pinedo, G Langanke, K Dean, DJ AF Martinez-Pinedo, G Langanke, K Dean, DJ TI Competition of electron capture and beta-decay rates in supernova collapse SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic processes; nuclear reactions, nucleosynthesis, abundances supernovae : general ID WEAK-INTERACTION RATES; GAMOW-TELLER STRENGTH; INTERMEDIATE-MASS NUCLEI; SHELL-MODEL; MONTE-CARLO; EVOLUTION; STARS; NI-56 AB We calculate supernova electron capture and beta-decay rates for various pf-shell nuclei using large-scale shell-model techniques. We show that the centroid of the Gamow-Teller strength distribution was systematically misplaced in previous rate estimates. Our total electron capture rates are significantly smaller than currently adopted in core collapse calculations, while the total beta-decay rates change less. Our calculation shows that for electron-to-baryon ratios, Y(e) = 0.42-0.46, beta-decay rates are larger than the competing electron capture rates. C1 Univ Aarhus, Inst Phys & Astron, Aarhus, Denmark. Univ Aarhus, Theoret Astrophys Ctr, Aarhus, Denmark. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP Martinez-Pinedo, G (reprint author), Univ Aarhus, Inst Phys & Astron, Aarhus, Denmark. EM martinez@ifa.au.dk RI Martinez-Pinedo, Gabriel/A-1915-2013; OI Martinez-Pinedo, Gabriel/0000-0002-3825-0131; Dean, David/0000-0002-5688-703X NR 30 TC 37 Z9 37 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2000 VL 126 IS 2 BP 493 EP 499 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 308VA UT WOS:000086732500009 ER PT J AU Mundorff, EC Hanson, MA Varvak, A Ulrich, H Schulz, PG Stevens, RC AF Mundorff, EC Hanson, MA Varvak, A Ulrich, H Schulz, PG Stevens, RC TI Conformational effects in biological catalysis: An antibody-catalyzed oxy-cope rearrangement SO BIOCHEMISTRY LA English DT Article ID MECHANISM; EVOLUTION; BINDING AB Antibody AZ-28 was generated against the chairlike transition-state analogue (TSA) 1 and catalyzes the oxy-Cope rearrangement of substrate 2 to product 3. The germline precursor to AZ-28 catalyzes the reaction with a 35-fold higher rate (k(cat)/k(uncat) = 163000), despite a 40-fold lower binding affinity for TSA.1 (K-D = 670 nM). To determine the structural basis for the differences in the binding and catalytic properties of the germline and affinity-matured antibodies, the X-ray crystal structures of the unliganded and TSA.1 complex of antibody AZ-28 have been determined at 2.8 and 2.6 Angstrom resolution, respectively; the structures of the unliganded and TSA.1 complex of the germline precursor to AZ-28 were both determined at 2.0 Angstrom resolution. In the affinity-matured antibody hapten complex the TSA is fixed in a catalytically unfavorable conformation by a combination of van der Waals and hydrogen-bonding interactions. The 2- and 5-phenyl substituents of TSA.1 are almost perpendicular to the cyclohexyl ring, leading to decreased orbital overlap and decreased stabilization of the putative transition state. The active site of the germline antibody appears to have an increased degree of flexibility-CDRH3 moves 4.9 Angstrom outward from the active site upon binding of TSA.1. We suggest that this conformational flexibility in the germline antibody, which results in a lower binding affinity for TSA.1, allows dynamic changes in the dihedral angle of the 2-phenyl substituent along the reaction coordinate. These conformational changes in turn lead to enhanced orbital overlap and increased catalytic rate. These studies Suggest that protein and substrate dynamics play a key role in this antibody-catalyzed reaction. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. Scripps Res Inst, Dept Chem & Mol Biol, La Jolla, CA 92037 USA. RP Stevens, RC (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 FU NIAID NIH HHS [AI39089] NR 26 TC 32 Z9 32 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 1 PY 2000 VL 39 IS 4 BP 627 EP 632 DI 10.1021/bi9924314 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 278WZ UT WOS:000085013100001 PM 10651626 ER PT J AU Lindberg, SE Vette, AF Miles, C Schaedlich, F AF Lindberg, SE Vette, AF Miles, C Schaedlich, F TI Mercury speciation in natural waters: Measurement of dissolved gaseous mercury with a field analyzer SO BIOGEOCHEMISTRY LA English DT Article DE gaseous; kinetics; mercury; methods; speciation; waters ID ATMOSPHERIC MERCURY; FLORIDA EVERGLADES; NUTRIENT REMOVAL; VOLATILE MERCURY; TEMPERATE LAKES; AIR; EXCHANGE; PROJECT; FLUXES; VAPOR AB Mercury evasion from water is commonly modeled using measurements of dissolved gaseous mercury (DGM). We developed a method using a recently available automated field-ready mercury vapor analyzer to rapidly measure the concentrations of DGM in surface waters. We summarize here results of laboratory tests of the method, field intercomparisons with a manual method, and selected data from recent sampling campaigns in Florida and Michigan. The method uses the 1.5 lpm flow of a Tekran(R) Model 2537A mercury analyzer to purge and analyze discrete water samples, generating near real time (5-min) data on DGM in samples and blanks. Application of the Tekran allowed for detailed analysis of DGM removal kinetics and short-term diel studies characterizing the influence of sunlight and precipitation on DGM production in surface waters. Gas removal kinetics for dozens of samples indicates a first-order rate constant, and supports a 20-min. purge time for surface water samples from Florida (40-min for Michigan samples). Blanks are measured during a second such purge. Our results indicate that DGMs determined by both automated and manual methods are generally comparable, and that DGM in Florida samples is unstable during storage (loss rate constant similar to 0.1-0.2 h(-1)), probably due to oxidation. This suggests that rapid in-field analysis is preferred to storage with delayed analysis. Our data indicate that DGM at the Florida site is influenced by inputs of reactive Hg in rainwater, and by production of surface DGM during photoreduction of oxidized Hg in the water column. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Michigan, Sch Publ Hlth, Air Qual Lab, Ann Arbor, MI 48109 USA. Univ Florida, Gainesville, FL USA. Tekran Inc, Toronto, ON, Canada. RP Lindberg, SE (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Vette, Alan/A-7330-2012 OI Vette, Alan/0000-0001-6749-1252 NR 37 TC 61 Z9 62 U1 2 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-2563 J9 BIOGEOCHEMISTRY JI Biogeochemistry PD FEB PY 2000 VL 48 IS 2 BP 237 EP 259 DI 10.1023/A:1006228612872 PG 23 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 269DN UT WOS:000084461300005 ER PT J AU Kozik, A Bradbury, EM Zalensky, AO AF Kozik, A Bradbury, EM Zalensky, AO TI Identification and characterization of a bovine sperm protein that binds specifically to single-stranded telomeric deoxyribonucleic acid SO BIOLOGY OF REPRODUCTION LA English DT Article ID DEFINED GENOME ARCHITECTURE; MEIOTIC PROPHASE; DNA; TRF1; RECOGNITION; NUCLEUS; LOCALIZATION; PURIFICATION; ORGANIZATION; TERMINUS AB Telomere DNA at the physical termini of chromosomes forms a single;stranded 3' overhang. In lower eukaryotes, e.g., ciliated protozoa, this DNA extension is capped by specific proteins that have been structurally and functionally characterized. Much less is known about single-stranded telomere DNA-binding proteins in vertebrates, Here we describe a new protein from bovine sperm designated bsSSTBP that specifically interacts with single-stranded (TTAGGG)(N) DNA. The bsSSTBP was extracted from nuclei by 0.6 M KCl. The native size of this protein, estimated by gel filtration, was 20-40 kDa. SOS-PACE of the UV cross-linked complex between bsSSTBP and telomere DNA indicated that several polypeptides are involved in complex formation. Bovine sSSTB had high specificity toward nucleotide sequence, since single nucleotide substitutions in the (TTAGGG), substrate suppressed binding. The minimal number of (TTAGGC) repeats required for binding of bsSSTBP was 3, and the protein recognized linear but not folded DNA structures. We propose that the bsSSTBP participates in telomere-telomere interactions and the telomere membrane localization observed in mature sperm. In mammals, somatic telomere-binding proteins are apparently substituted by sperm-specific ones that may lead to a structural reorganization of telomere domains to fulfill functions important during meiosis and fertilization. C1 Univ Calif Davis, Sch Med, Dept Biol Chem, Davis, CA 95616 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Zalensky, AO (reprint author), Univ Calif Davis, Sch Med, Dept Biol Chem, Davis, CA 95616 USA. NR 43 TC 8 Z9 9 U1 0 U2 0 PU SOC STUDY REPRODUCTION PI MADISON PA 1603 MONROE ST, MADISON, WI 53711-2021 USA SN 0006-3363 J9 BIOL REPROD JI Biol. Reprod. PD FEB PY 2000 VL 62 IS 2 BP 340 EP 346 DI 10.1095/biolreprod62.2.340 PG 7 WC Reproductive Biology SC Reproductive Biology GA 278JV UT WOS:000084987400016 PM 10642571 ER PT J AU Keller, D Bustamante, C AF Keller, D Bustamante, C TI The mechanochemistry of molecular motors SO BIOPHYSICAL JOURNAL LA English DT Article ID SINGLE KINESIN MOLECULES; RNA-POLYMERASE; FORCE GENERATION; DRIVEN RATCHETS; ATP HYDROLYSIS; MOTION; MODEL; MECHANISM; TRANSPORT; KINETICS AB A theory of molecular motors is presented that explains how the energy released in single chemical reactions can generate mechanical motion and force. In the simplest case the fluctuating movements of a motor enzyme are well described by a diffusion process on a two-dimensional potential energy surface, where one dimension is a chemical reaction coordinate and the other is the spatial displacement of the motor. The coupling between chemistry and motion results from the shape of the surface, and motor velocities and forces result from diffusion currents on this surface. This microscopic description is shown to possess an equivalent kinetic mechanism in which the rate constants depend on externally applied forces. By using this equivalence we explore the characteristic properties of several broad classes of motor mechanisms and give general expressions for motor velocity versus load force for any member of each class. We show that in some cases simple plots of 1/velocity vs. 1/concentration can distinguish between classes of motor mechanisms and may be used to determine the step at which movement occurs. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Univ Calif Berkeley, Dept Mol & Cellular Biol, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Bustamante, C (reprint author), Univ Calif Berkeley, Dept Phys, 173 Birge Hall, Berkeley, CA 94720 USA. NR 34 TC 183 Z9 188 U1 6 U2 35 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 2000 VL 78 IS 2 BP 541 EP 556 PG 16 WC Biophysics SC Biophysics GA 282YL UT WOS:000085249300001 PM 10653770 ER PT J AU Bryant, Z Pande, VS Rokhsar, DS AF Bryant, Z Pande, VS Rokhsar, DS TI Mechanical unfolding of a beta-hairpin using molecular dynamics SO BIOPHYSICAL JOURNAL LA English DT Article ID TITIN IMMUNOGLOBULIN DOMAINS AB Single-molecule mechanical unfolding experiments have the potential to provide insights into the details of protein folding pathways. To investigate the relationship between force-extension unfolding curves and microscopic events, we performed molecular dynamics simulations of the mechanical unfolding of the C-terminal hairpin of protein G. We have studied the dependence of the unfolding pathway on pulling speed, cantilever stiffness, and attachment points, Under conditions that generate low forces, the unfolding trajectory mimics the untethered, thermally accessible pathway previously proposed based on high-temperature studies. In this stepwise pathway, complete breakdown of backbone hydrogen bonds precedes dissociation of the hydrophobic cluster. Under more extreme conditions, the cluster and hydrogen bonds break simultaneously. Transitions between folding intermediates can be identified in our simulations as features of the calculated force-extension curves. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Rokhsar, DS (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 20 TC 58 Z9 58 U1 0 U2 9 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 2000 VL 78 IS 2 BP 584 EP 589 PG 6 WC Biophysics SC Biophysics GA 282YL UT WOS:000085249300004 PM 10653773 ER PT J AU O'Keefe, DM Brigmon, RL Chynoweth, DP AF O'Keefe, DM Brigmon, RL Chynoweth, DP TI Influence of methane enrichment by aeration of recirculated supernatant on microbial activities during anaerobic digestion SO BIORESOURCE TECHNOLOGY LA English DT Article DE anaerobic digestion; methane enrichment; ELISA; dehydrogenase; methane production; microbial inhibition ID FERMENTATION AB A methane enrichment process (MEP) was evaluated that involved air purging of recycled digester contents to strip CO2 and increase biogas methane content. The objective of this work was to determine if the aeration resulted in oxygen inhibition of microbial activities involved in anaerobic digestion of municipal solid waste. To assess the degree of biological perturbation associated with the MEP, the reactor effluent was sampled twice while the MEP was operating and twice while it was not operating. Analyses were run on composite samples (representing several different sample ports of the non-mixed reactor) and samples of digester effluent entering and leaving the MEP process. The analyses included volatile organic acids (VOA), effluent solids content, dehydrogenase activity, specific methanogenic activities (SMA), and enzyme-linked immunosorbent assay (ELISA) for methanogenic, sulfate-reducing, and cellulolytic bacterial species. Methane enrichment in these experiments occurred with the methane content of the biogas exceeding 90%. There were no effects of the MEP on effluent VOA concentration. The MEP had no effect on volatile solids (VS) levels of composite samples representing the non-mixed digester contents, however, VS was reduced in effluent passing through the MEP. Although MEP had an inhibitory effect on anaerobic populations leaving the MEP process, no inhibitory effects were observed in measurements of microbial activities in digester samples, including specific methane production rate, dehydrogenase, and numbers of specific organisms estimated using ELISA techniques. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Agr & Biol Engn, Gainesville, FL 32611 USA. Savannah River Technol Ctr, Aiken, SC 29808 USA. Full Circle Solut Inc, Gainesville, FL 32641 USA. RP Chynoweth, DP (reprint author), Univ Florida, Dept Agr & Biol Engn, Gainesville, FL 32611 USA. NR 14 TC 10 Z9 11 U1 1 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0960-8524 J9 BIORESOURCE TECHNOL JI Bioresour. Technol. PD FEB PY 2000 VL 71 IS 3 BP 217 EP 224 DI 10.1016/S0960-8524(99)90073-1 PG 8 WC Agricultural Engineering; Biotechnology & Applied Microbiology; Energy & Fuels SC Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels GA 256AT UT WOS:000083703000003 ER PT J AU Jackson, BP Lasier, PJ Miller, WP Winger, PW AF Jackson, BP Lasier, PJ Miller, WP Winger, PW TI Effects of calcium, magnesium, and sodium on alleviating cadmium toxicity to Hyalella azteca SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID TROUT SALMO-GAIRDNERI; CENTRAL ONTARIO LAKES; WATER HARDNESS; RAINBOW-TROUT; SALINITY; AMPHIPODA; COPPER; PH; ALKALINITY; CRUSTACEA C1 Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Aiken, SC 29802 USA. Univ Georgia, Warnell Sch Forest Resources, Patuxent Wildlife Res Ctr, US Geol Survey, Athens, GA 30602 USA. Univ Georgia, Dept Crop & Soil Sci, Athens, GA 30602 USA. RP Jackson, BP (reprint author), Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, PO Drawer E, Aiken, SC 29802 USA. NR 19 TC 24 Z9 26 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD FEB PY 2000 VL 64 IS 2 BP 279 EP 286 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 278MU UT WOS:000084994200018 PM 10656896 ER PT J AU Myers, SC Schultz, CA AF Myers, SC Schultz, CA TI Improving sparse network seismic location with Bayesian kriging and teleseismically constrained calibration events SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID HYPOCENTER LOCATION; EARTHQUAKE LOCATION; TRAVEL-TIMES; TECTONICS; ERRORS; MODEL AB Monitoring the Comprehensive Nuclear-Test-Ban Treaty will require improved seismic location capability for small-magnitude events, The International Monitoring System (IMS) is well suited to locate events that are large enough to be recorded at teleseismic distances. However, small events are likely to be recorded on a sparse subset of IMS stations at regional- to upper-mantle distances (less than 30 degrees), and sparse-network locations can be strongly effected by travel-time errors that result from path-specific velocity model inaccuracies. In an effort to improve sparse network location capability, we outline a procedure that applies empirical corrections to travel times determined with an appropriate velocity model. More specifically, Bayesian kriging and calibration events (constrained with a global network) are used to estimate epicenter-specific travel-time corrections. For a test (sparse) network of stations, we calculate travel-time residuals for the calibration events relative to the ak135 velocity model. Travel-time residuals are assigned to the respective calibration epicenter, forming a set of spatially varying travel-time correction points. The spatial set of correction points is declustered to reduce the dimension of the observations with minimal reduction in accuracy of the travel-time corrections. We then use the declustered set of calibration points and Bayesian kriging to form continuous travel-time correction surfaces for each station of the test network. The effectiveness of travel-time correction surfaces is evaluated by locating, with and without corrections, a subset of the 1991 Racha earthquake sequence (Caucasus Mountains), for which we have accurate locations that were independently determined with a dense local network. When no travel-time correction is applied, the mean horizontal distance between the local and test network locations is 42 km, and there is a distinct bias in sparse-network locations toward the north-northwest. The mean difference between local and sparse network locations is cut to 13 km when corrections are applied, and the bias in location is significantly reduced. When calibration events in the Racha vicinity are not used to make the correction surfaces, there is still a significant improvement in location, with mean mislocations of 15 km, When corrections are not applied, only one of the locally determined locations lies within the associated 90% coverage ellipse determined with the test (sparse) network. However, by using traveltime corrections and estimates of model uncertainty determined using kriging, representative error ellipses are obtained. This study demonstrates that kriging correction surfaces based on global-network-constrained calibration events can improve the ability to accurately locate lower magnitude events while providing representative coverage ellipses. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Myers, SC (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-205,POB 808, Livermore, CA 94551 USA. RI Myers, Stephen/K-1368-2014 OI Myers, Stephen/0000-0002-0315-5599 NR 20 TC 32 Z9 35 U1 0 U2 4 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 FEB PY 2000 VL 90 IS 1 BP 199 EP 211 DI 10.1785/0119980171 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 293NU UT WOS:000085859700014 ER PT J AU Phillips, WS AF Phillips, WS TI Precise microearthquake locations and fluid flow in the geothermal reservoir at Soultz-sous-Forets, France SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID CROSS-CORRELATION; CRYSTALLINE ROCK; EARTHQUAKES; CALIFORNIA; PARKFIELD; SEQUENCE; CLUSTERS; MEXICO; FAULT; ZONE AB I relocated two microearthquake clusters induced by hydraulic stimulation of a hot-dry-rock geothermal reservoir in the Rhine Graben near Soultz-sous-Forets, France. The two clusters were chosen from a collection of clusters identified within a 16,000-event data set obtained in 1993. I determined P- and S-wave arrival times, manually, choosing distinctive peaks if waveforms were similar at a given station, or first breaks if waveforms were emergent or nodal, judging weights accordingly. Requiring a minimum of five arrival times yielded populous clusters of 226 and 355 events. In both cases, relocation revealed two distinct planar patches of activity, 100 to 200 m across, intersecting and truncating one another along a common edge. Linear segments traverse the planar patches and may mark intersections with seismically inactive fractures. The earliest activity occurred along these segments. These segments may therefore mark permeable zones that could be important components of the fluid-flow network. The interpretation of linear segments as flow paths is supported by path dimension constraints derived from fluid-flow modeling studies and by the expected confining effects of hydrothermal sealing found in cored fractures. Orientations of the planar features are verified through consistency with orientations found in core and logging studies. In addition, focal mechanisms obtained by constraining slip planes parallel to active planes indicate normal to right-lateral strike slip, consistent with the measured stress field. Focal mechanisms indicate mass deficits at inside corners, implying that the concentrations of activity at fracture intersections may result from slip on one fracture causing extension and a resulting permeability increase in the other. The improved location precision results from a ten-fold improvement in the precision of arrival-time estimation for phases that were similar, as estimated from the standard deviation of residuals, grouped by station and phase, before and after repicking. Only a two-fold improvement was noted for poorly correlated or nodal phases. For this data set, the manual phase picking yielded more interpretable detail in the location patterns, compared to results of an automatic, cross-correlation technique. The manual results could be used to guide improvements to automatic techniques to obtain precise locations of the entire data set. C1 Univ Calif Los Alamos Natl Lab, Seism Res Ctr, Los Alamos, NM 87545 USA. RP Phillips, WS (reprint author), Univ Calif Los Alamos Natl Lab, Seism Res Ctr, POB 1663, Los Alamos, NM 87545 USA. NR 45 TC 40 Z9 43 U1 2 U2 6 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 FEB PY 2000 VL 90 IS 1 BP 212 EP 228 DI 10.1785/0119990047 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 293NU UT WOS:000085859700015 ER PT J AU Nagle, RD Kinney, OM Congdon, JD Beck, CW AF Nagle, RD Kinney, OM Congdon, JD Beck, CW TI Winter survivorship of hatchling painted turtles (Chrysemys picta) in Michigan SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID SUBZERO TEMPERATURES; HATCHING SUCCESS; FREEZE TOLERANCE; NESTING ECOLOGY; COLD-TOLERANCE; MORTALITY; EVOLUTIONARY; HIBERNATION; DEMOGRAPHY; MARGINATA AB Hatchling painted turtles (Chrysemys picta) often exhibit delayed emergence by remaining in shallow sub- terranean nest cavities throughout winter. As a result, those at northern latitudes are sometimes exposed to lethal subzero temperatures. Our field study compared survivorship of hatchling C. picta during a winter in which low subzero temperatures coincided with the absence of insulating snow cover (1995-1996) with survivorship during the following three winters (1996-1997, 1997-1998, and 1998-1999), which were characterized by more moderate conditions. Ambient-air and soil temperatures were monitored at a weather station located within similar to 1 km of all nests. During the first winter of our study (1995-1996), minimum ambient-air temperature reached -25.6%C on 2 February, concomitantly with the complete absence of snow cover, and soil temperatures fell to between -7 and -9%C. Resultant over-winter hatchling mortality was 45%. Because some hatchlings survived temperatures well below the lethal limits described for freeze tolerance (-1 to -4%C), it is likely that hatchlings in Michigan sometimes survive by supercooling. During the following three winters, soil temperatures remained above -2%C, except during brief periods when they fell to -4%C in the absence of snow cover. Over-winter hatchling mortality was < 3% during each of these last 3 years. Our study highlights the importance of insulating snow cover to survival of hatchling C. picta. Air temperature and snowfall data from southeastern Michigan over the past 33 years indicate that conditions associated with substantial winter mortality occurred in 3 out of 33 years (9.1%). We demonstrate that the impact of substantial over-winter mortality on hatchling recruitment is dependent on nest survivorship during the preceding nesting season. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Georgia, Inst Ecol, Athens, GA 30602 USA. RP Nagle, RD (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 33 TC 24 Z9 24 U1 2 U2 17 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD FEB PY 2000 VL 78 IS 2 BP 226 EP 233 DI 10.1139/cjz-78-2-226 PG 8 WC Zoology SC Zoology GA 292XG UT WOS:000085820200008 ER PT J AU Weiden, PL Breitz, HB Press, O Appelbaum, JW Bryan, JK Gaffigan, S Stone, D Axworthy, D Fisher, D Reno, J AF Weiden, PL Breitz, HB Press, O Appelbaum, JW Bryan, JK Gaffigan, S Stone, D Axworthy, D Fisher, D Reno, J TI Pretargeted radioimmunotherapy (PRIT (TM)) for treatment of non-Hodgkin's lymphoma (NHL): Initial phase I/II study results SO CANCER BIOTHERAPY AND RADIOPHARMACEUTICALS LA English DT Article DE PRIT; pretargeted radioimmunotherapy; non-Hodgkin's lymphoma; Y-90; streptavidin; RIT; radioimmunotherapy ID B-CELL LYMPHOMA; ANTIBODY THERAPY; ANTI-CD20 ANTIBODY; I-131; TOXICITY AB Pretargeted radioimmunotherapy (PRIT(TM)) was investigated in patients with non-Hodgkin's lymphoma (NHL). The PRIT approach used in this study is a multi-step delivery system in which an antibody is used to target streptavidin to a tumor associated antigen receptor and subsequently biotin is then used to target Y-90 radioisotope to the tumor localized streptavidin. A chimeric IgG1, anti-CD20 antibody, designated C2B8 or Rituximab, was conjugated to streptavidin (SA) and administered to patients with NHL. Thirty-four hours later, a clearing agent, synthetic biotin-N-acetyl-galactosamine, was administered to remove non-localized conjugate from the circulation. Finally, a DOTA-biotin ligand, labeled with In-111 for imaging and/or Y-90 for therapy was administered Ten patients with relapsed or refractory NHL were studied. In three patients, the C2B8/SA conjugate was radiolabeled with a trace amount of Re-186 in order to assess pharmacokinetics and biodistribution using gamma camera imaging. Seven patients received 30 or 50 mCi/m(2) Y-90 DOTA-biotin. Re-186 C2B8/SA images confirmed that the conjugate localized to known tumor sites and that the clearing agent removed >95% of the conjugate from the circulation. Radiolabeled biotin localized well to tumor. Unbound radiobiotin was rapidly excreted from the whole body and normal organs. The mean tumor dose calculated was 29 +/- 23 cGy/mCi Y-90 and the average whole body dose was 0.76 +/- 0.3 cGy/mCi Y-90, resulting in a mean tumor to whole body dose ratio of 38:1. Only grade I/II non-hematologic toxicity was observed Hematologic toxicity was also not severe; i.e., five of the seven patients who received -30 or 50 mCi/m(2) of Y-90-DOTA-biotin experienced only transient grade III (but no grade ly) hematologic toxicity. Although six of ten patients developed humoral immune responses to the streptavidin, these were delayed and transient and hence may not preclude retreatment. Six of seven patients who received 30 or 50mCi/m(2) Y-90 achieved objective tumor regression, including three complete and one partial response. The estimate of tumor to whole body dose ratio (38:1) achieved with PRIT in these NHL patients is higher than has been achieved in other studies using conventional RIT. Toxicity was mild and tumor response encouraging. PRIT clearly deserves additional study in patients with NHL. C1 Virginia Mason Med Ctr, Dept Med, Hematol Oncol Sect, Seattle, WA 98111 USA. Univ Washington, Sch Med, Seattle, WA USA. NeoRx Corp, Seattle, WA USA. Pacific NW Natl Lab, Richland, WA USA. RP Weiden, PL (reprint author), Virginia Mason Med Ctr, Dept Med, Hematol Oncol Sect, 1100 9th Ave,POB 900 H14-HEM, Seattle, WA 98111 USA. NR 24 TC 95 Z9 95 U1 0 U2 3 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1084-9785 J9 CANCER BIOTHER RADIO JI Cancer Biother. Radiopharm. PD FEB PY 2000 VL 15 IS 1 BP 15 EP 29 DI 10.1089/cbr.2000.15.15 PG 15 WC Oncology; Medicine, Research & Experimental; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Research & Experimental Medicine; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging GA 313NP UT WOS:000087006000003 PM 10740649 ER PT J AU Anderson, LE Morris, JE Sasser, LB Stevens, RG AF Anderson, LE Morris, JE Sasser, LB Stevens, RG TI Effect of constant light on DMBA mammary tumorigenesis in rats SO CANCER LETTERS LA English DT Article DE mammary gland development; light exposure; mammary cancer; dimethylbenzanthracene; carcinogenesis; rats ID BREAST-CANCER RISK; ELECTRIC-POWER; VARYING PHOTOPERIODS; HYPOTHESIS; MELATONIN; GROWTH AB A study of light, and mammary tumorigenesis was conducted in rats. One-hundred female Sprague-Dawley rats were divided by weight into two groups. One group was exposed to constant light (LL) from 26 days of age, and the second group was exposed to 8 h light and 16 h dark per day (LD). Both groups received an 8 mg dose of a chemical carcinogen, dimethylbenzanthracene (DMBA) at 52 days of age. At 13 weeks post-DMBA, there were significantly fewer mammary tumors in the LL group compared with the LD group. Constant light was clearly demonstrated to have a profound effect on mammary tissue development. Although virgin, the majority of the LL rats (29/50) had gross evidence of lactation at 141 days of age. None of the LD rats (0/50) showed evidence of milk production. These results suggest that constant light not only substantially accelerated mammary gland development, but pushed development of the tissue past the stage normally observed in virgin animals (to the lactation stage). (C) 2000 Elsevier Science ireland Ltd. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Anderson, LE (reprint author), Pacific NW Lab, POB 999,MS-P7-53, Richland, WA 99352 USA. NR 22 TC 29 Z9 32 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0304-3835 J9 CANCER LETT JI Cancer Lett. PD FEB 1 PY 2000 VL 148 IS 2 BP 121 EP 126 DI 10.1016/S0304-3835(99)00320-1 PG 6 WC Oncology SC Oncology GA 278UT UT WOS:000085007900002 PM 10695987 ER PT J AU Niu, SQ Hall, MB AF Niu, SQ Hall, MB TI Theoretical studies on reactions of transition-metal complexes SO CHEMICAL REVIEWS LA English DT Review ID ORGANOMETALLIC REACTION-MECHANISMS; C-H ACTIVATION; SIGMA-BOND METATHESIS; OLEFIN INSERTION REACTION; ETHYLENE POLYMERIZATION REACTION; CONSTRAINED-GEOMETRY CATALYSTS; CARBON-MONOXIDE SUBSTITUTION; OXIDATIVE-ADDITION-REACTIONS; MOLLER-PLESSET PERTURBATION; EFFECTIVE CORE POTENTIALS C1 Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. RP Hall, MB (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Hall, Michael/B-9118-2013 OI Hall, Michael/0000-0003-3263-3219 NR 444 TC 687 Z9 691 U1 10 U2 130 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2665 EI 1520-6890 J9 CHEM REV JI Chem. Rev. PD FEB PY 2000 VL 100 IS 2 BP 353 EP 405 DI 10.1021/cr980404y PG 53 WC Chemistry, Multidisciplinary SC Chemistry GA 284FD UT WOS:000085319500002 ER PT J AU Gallegos, JJ Ward, TL Boyle, TJ Rodriguez, MA Francisco, LP AF Gallegos, JJ Ward, TL Boyle, TJ Rodriguez, MA Francisco, LP TI Neo-pentoxide precursors for MOCVD thin films of TiO2 and ZrO2 SO CHEMICAL VAPOR DEPOSITION LA English DT Article DE metal alkoxide; neo-pentoxide; anatase; zirconium oxide ID CHEMICAL-VAPOR-DEPOSITION; CVD AB Two group IV precursors, titanium(IV) neo-pentoxide, [Ti(mu-ONep)(ONep)(3)](2) (1, where ONep = OCH2C(CH3)(3)), and zirconium(IV) neo-pentoxide, [Zr(mu-ONep)(ONep)(3)](2) (2), were found to possess relatively high volatility at low temperatures. These compounds were therefore investigated as metal-organic CVD (MOCVD) precursors using a lamp-heated cold-wall CVD reactor by direct vaporization without a carrier gas. The ONep derivatives proved to be competitive precursors for the production of thin films of the appropriate MO2 (M = Ti or Zr) materials in comparison to other metallo-organic precursors. Compound 1 was found to vaporize at 120 degrees C with a deposition rate of similar to 0.350 mu m/min onto a substrate at 330 degrees C forming the anatase phase with <1 % residual C found in the final film. Compound 2 was found to vaporize at 160 degrees C and deposited a crystalline material at 300 degrees C with <1% residual C found in the final film. A comparison with standard alkoxide and beta-diketonates is presented where appropriate. C1 Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. Univ New Mexico, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. RP Gallegos, JJ (reprint author), Sandia Natl Labs, Adv Mat Lab, 1001 Univ Blvd SE, Albuquerque, NM 87106 USA. NR 20 TC 42 Z9 42 U1 0 U2 3 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0948-1907 J9 CHEM VAPOR DEPOS JI Chem. Vapor Depos. PD FEB PY 2000 VL 6 IS 1 BP 21 EP 26 DI 10.1002/(SICI)1521-3862(200002)6:1<21::AID-CVDE21>3.0.CO;2-C PG 6 WC Electrochemistry; Materials Science, Coatings & Films; Physics, Condensed Matter SC Electrochemistry; Materials Science; Physics GA 281CW UT WOS:000085141400008 ER PT J AU Ward, BH Schlueter, JA Geiser, U Wang, HH Morales, E Parakka, JP Thomas, SY Williams, JM Nixon, PG Winter, RW Gard, GL Koo, HJ Whangbo, MH AF Ward, BH Schlueter, JA Geiser, U Wang, HH Morales, E Parakka, JP Thomas, SY Williams, JM Nixon, PG Winter, RW Gard, GL Koo, HJ Whangbo, MH TI Comparison of the crystal and electronic structures of three 2 : 1 salts of the organic donor molecule BEDT-TTF with pentafluorothiomethylsulfonate anions SF5CH2SO3-, SF5CHFSO3-, and SF5CF2SO3- SO CHEMISTRY OF MATERIALS LA English DT Article ID SPIN-PEIERLS TRANSITION; AMBIENT-PRESSURE SUPERCONDUCTIVITY; CHARGE-TRANSFER SALTS; BAND-STRUCTURE; INTERMOLECULAR INTERACTIONS; PHYSICAL-PROPERTIES; TEMPERATURE; SYSTEM; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; KAPPA-(BEDT-TTF)(2)CUBR AB Salts of the donor molecule, bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET), with pentafluorothiomethylsulfonate (SF5CX2SO3-, X = H or F) anions have been prepared. Three phases, beta"-(ET)(2)SF5CH2SO3, beta'-(ET)(2)SF5CF2SO3, and beta"-(ET)(2)SF5CHFSO3 were obtained by electrocrystallization with the corresponding LiSF5CX2SO3 electrolytes. The structures of these salts were determined by sing;le-crystal X-ray diffraction, and their physical properties were examined by electrical resistivity measurements as well as by ESR and Raman spectroscopy. The beta"-(ET)(2)SF5CH2SO3, beta-(ET)(2)SF5CHFSO3 and beta-(ET)(2)SF5CF2SO3 salts are considerably different in their crystal structures, physical properties, and electronic structures despite the similarity in the structures of the SF5CX2SO3- (X = H, F) anions. The beta"-(ET)(2)SF5-CH2SO3 salt has two kinds of ET donor molecules with considerably different charge densities. The electronic structure of beta"-(ET)(2)SF5CHFSO3 has both one-dimensional (1D) and two-dimensional (2D) Fermi surfaces which are similar to those found in the organic superconductor beta"-(ET)(2)SF5CH2CF2SO3. The ESR data for the beta'-(ET)(2)SF5CF2SO3 salt indicate that it opens a spin gap below 45 K. The differences in the physical properties of the three salts were analyzed by calculating the HOMO-HOMO interaction energies between nearest-neighbor ET molecules in their donor molecule layers. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 48 TC 46 Z9 46 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 EI 1520-5002 J9 CHEM MATER JI Chem. Mat. PD FEB PY 2000 VL 12 IS 2 BP 343 EP 351 DI 10.1021/cm990238q PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 287JN UT WOS:000085502900018 ER PT J AU McDaniel, AH Allendorf, MD AF McDaniel, AH Allendorf, MD TI Autocatalytic behavior of trimethylindium during thermal decomposition SO CHEMISTRY OF MATERIALS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; GALLIUM-RICH GAAS(100); CARRIER GAS; PHASE EPITAXY; KINETICS; TRIMETHYLGALLIUM; GROWTH; PYROLYSIS; METHYL; SPECTROSCOPY AB Pyrolysis of trimethylindium (TMIn) in a hot-wall flow-tube reactor has been investigated at temperatures between 573 and 723 K using a modulated molecular-beam mass-sampling technique and detailed numerical modeling. The TMIn was exposed to various mixtures of carrier gases: He, H-2, D-2, and C2H4, in an effort to elucidate the behavior exhibited by this compound in different chemical environments. The decomposition of TMIn is a heterogeneous, autocatalytic process with an induction period that is carrier-gas dependent and lasts on the order of minutes. After activation of the tube wall, the thermolysis exhibits a steady-state behavior that is surface mediated. This result is contrary to prior literature reports, which state that decomposition occurs in the gas phase via successive loss of the CH3 ligands. This finding also suggests that the bond dissociation energy for the (CH3)(2)In-CH3 bond derived from flow-tube investigations is erroneous and should be reevaluated. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP McDaniel, AH (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 52 TC 11 Z9 11 U1 0 U2 5 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 FEB PY 2000 VL 12 IS 2 BP 450 EP 460 DI 10.1021/cm990497f PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 287JN UT WOS:000085502900033 ER PT J AU Zhang, H Bartlett, RJ AF Zhang, H Bartlett, RJ TI Light-induced disappearance of nitrite in the presence of iron (III) SO CHEMOSPHERE LA English DT Article ID HYDROGEN-PEROXIDE; AQUEOUS-SOLUTION; NITROUS-ACID; PHOTOLYSIS; CONSUMPTION; OXIDATION; KINETICS; WATERS; CLOUDS; FOG AB Understanding of rapid disappearance of nitrite in natural waters and its impact on nitrogen natural cycling has remained limited. We found that NO2- disappeared rapidly in pH 3.2 aqueous Fe(III) solutions both in sunlight and in 356 nm light. Quantum yields of the NO; loss at 356 nm were 0.049-0.14 for initial levels of 10-80 mu m NO2- and 200 mu m Fe(III). The NO2- loss (at 356 nm) followed apparent first-order kinetics. The rate constants were 1.3x10(-3) (40 mu m NO2-) and 4.1 x 10(-4) s(-1) (80 mu m NO2-) for 100 mu m Fe(III), and 2.3 x 10(-3) (40 mu m NO2-) and 7.5 x 10(-4) s(-1) (80 mu m NO2-1) for 200 mu m Fe(III) (t(1/2) = 8.7, 27.9, 5.1, and 15.3 min, respectively). The rate constants were directly proportional to [Fe(III)](o) and inversely proportional to [NO2-](o). Agreement between the rate constants obtained experimentally and those calculated mechanistically supports the hypothesis that NO2- was oxidized to NO2 by (OH)-O-. radicals from photolysis of FeOH2+ complexes, and at high [NO2-](o) (e.g., 80 mu m) relative to [Fe(III)](o), hydrolysis of NO2 or N2O4 to form NO3- and NO2- could be significant. This study showed that light and Fe(III)-induced oxidation of NO2- (rate = similar to 10(-1)- 10(-2) mu m s(-1)) was more rapid than its direct photolysis (rate = similar to 10(-4) mu m s(-1)), and the photolysis could be a significant source of (OH)-O-. radicals only in cases where the Fe(III) level is much lower than the NO2- level ([Fe(III)]/[NO2-] < 1/80). This study suggests that the light and Fe(III)-induced oxidation of NO2- would be one potential important pathway responsible for the rapid transformation of NO2- in acidic surface waters, especially those affected by acid-mine drainage or volcanic activities. This study also may be of interest for modeling certain acidic atmospheric water environments. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Vermont, Dept Plant & Soil Sci, Burlington, VT 05405 USA. RP Zhang, H (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 20 TC 4 Z9 4 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD FEB PY 2000 VL 40 IS 4 BP 411 EP 418 DI 10.1016/S0045-6535(99)00295-7 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA 270GN UT WOS:000084527200012 PM 10665407 ER PT J AU Xu, WZ Johnston, CT Parker, P Agnew, SF AF Xu, WZ Johnston, CT Parker, P Agnew, SF TI Infrared study of water sorption on Na-, Li-, Ca-, and Mg-exchanged (SWy-1 and SAz-1) montmorillonite SO CLAYS AND CLAY MINERALS LA English DT Article DE exchangeable cation; FTIR; hydration; hysteresis; smectite; sorption; water ID INTERLAYER MOLECULAR-STRUCTURE; MONTE-CARLO SIMULATION; SWELLING CLAY-MINERALS; HOMOIONIC MONTMORILLONITE; VAPOR; ADSORPTION; DESORPTION; CHARGE; SPECTROSCOPY; MECHANISM AB An environmental infrared microbalance (EIRM) cell was used to study H2O sorption on two montmorillonite samples as a function of water content and type of exchangeable cation. The vibrational spectra showed that H2O sorbed to the clay at low-water content was strongly influenced by the exchangeable cation and by the close proximity to the clay surface. At water contents <6 H2O molecules per exchangeable cation, the H-O-H bending mode of H2O (nu(2) mode) shifts to a lower frequency and is characterized by an increase in molar absorptivity. In contrast, the positions of the asymmetric and symmetric OH-stretching modes of sorbed water (nu(1) and nu(3) modes) shift to higher energies. These observations indicate that H2O molecules sorbed to the clay surface at low-water content are less hydrogen bonded than in bulk H2O, In addition, the vibrational-stretching and bending bands of the structural OW groups of the 2:1 layer are also strongly influenced by H2O content and type of exchangeable cation. By using the EIRM cell, the molar absorptivities of the structural OH-bending vibrations were measured as a function of H2O content. The position and molar absorptivity of the structural OH-bending bands at 920, 883, and 840 cm(-1) are strongly influenced by H2O content and type of exchangeable cation. The molar absorptivity of the 920-cm(-1) band, which is assigned to the AlAlOH group, decreased strongly at low-H2O content. This reduction in intensity is assigned to a dehydration-induced change in orientation of the structural OH groups resulting from the penetration of H2O molecules into siloxane ditrigonal cavities that are not associated with a net negative charge from isomorphous substitutions. C1 Purdue Univ, Dept Agron, W Lafayette, IN 47907 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Xu, WZ (reprint author), Purdue Univ, Dept Agron, W Lafayette, IN 47907 USA. RI Johnston, Cliff/B-2215-2009 OI Johnston, Cliff/0000-0002-8462-9724 NR 41 TC 107 Z9 110 U1 6 U2 41 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 FEB PY 2000 VL 48 IS 1 BP 120 EP 131 DI 10.1346/CCMN.2000.0480115 PG 12 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 287XZ UT WOS:000085533900015 ER PT J AU Knox, SJ Goris, ML Tempero, M Weiden, PL Gentner, L Breitz, H Adams, GP Axworthy, D Gaffigan, S Bryan, K Fisher, DR Colcher, D Horak, ID Weiner, LM AF Knox, SJ Goris, ML Tempero, M Weiden, PL Gentner, L Breitz, H Adams, GP Axworthy, D Gaffigan, S Bryan, K Fisher, DR Colcher, D Horak, ID Weiner, LM TI Phase II trial of yttrium-90-DOTA-biotin pretargeted by NR-LU-10 antibody/streptavidin in patients with metastatic colon cancer SO CLINICAL CANCER RESEARCH LA English DT Article ID MONOCLONAL-ANTIBODIES; RADIOIMMUNOTHERAPY; RADIONUCLIDES; CARCINOMA; LUNG; MICE AB A Phase II study of yttrium-90-tetra-azacyclododecanetetra-acetic acid-biotin (Y-90-DOTA-biotin) pretargeted by NR-LU-10 antibody/streptavidin (SA) was performed. The primary objectives of the study were to evaluate the efficacy and safety of this therapy in patients with metastatic colon cancer. Twenty-five patients,were treated with a single dose of 110 mCi/m(2) (mean administered dose, 106.5 +/- 10.3 mCi/m(2)) of Y-90- DOTA-biotin. There were three components of the therapy. Patients first received NR-LU-10/SA on day 1. A clearing agent (biotin-galactose-human serum albumin) was administered similar to 48 h after the NR-LU-10/SA to remove residual circulating unbound NR-LU-10/SA. Lastly, 24 h after administration of clearing agent, patients received biotin-DOTA-labeled with 110 mCi/m(2) Y-90. All three components of the therapy were administered i.v. Both hematological and nonhematological toxicities were observed, Diarrhea was the most frequent grade 4 nonhematological toxicity (16%; with 16% grade 3 diarrhea). Hematological toxicity was less severe with 8% grade 3 and 8% grade 4 neutropenia and 8% grade 3 and 16% grade 1 thrombocytopenia. The overall response rate nas 8%. Two partial responders had freedom from progression of 16 weeks. Four patients (16%) had stable disease with freedom from progression of 10-20,weeks. Despite the relatively disappointing results of this study in terms of therapeutic efficacy and toxicity, proof of principle was obtained for the pretargeting approach. In addition, valuable new. information was obtained about normal tissue tolerance to low-dose-rate irradiation that will help to provide useful guidelines for future study designs. C1 Stanford Univ, Sch Med, Med Ctr, Dept Radiat Oncol A 093, Stanford, CA 94305 USA. Stanford Univ, Sch Med, Dept Diagnost Radiol, Div Nucl Med, Stanford, CA 94305 USA. Univ Nebraska, Med Ctr, Eppley Canc Ctr, Omaha, NE 68198 USA. Janssen Res Fdn, Titusville, NJ 08560 USA. Fox Chase Canc Ctr, Dept Med Oncol, Philadelphia, PA 19111 USA. NEORX Corp, Seattle, WA 98119 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Knox, SJ (reprint author), Stanford Univ, Sch Med, Med Ctr, Dept Radiat Oncol A 093, Stanford, CA 94305 USA. FU NCRR NIH HHS [M01-RR00070] NR 30 TC 153 Z9 156 U1 1 U2 7 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 1078-0432 J9 CLIN CANCER RES JI Clin. Cancer Res. PD FEB PY 2000 VL 6 IS 2 BP 406 EP 414 PG 9 WC Oncology SC Oncology GA 287JK UT WOS:000085502600013 PM 10690517 ER PT J AU Schinazi, RF Hurwitz, SJ Liberman, I Juodawlkis, AS Tharnish, P Shi, JX Liotta, DC Coderre, JA Olson, J AF Schinazi, RF Hurwitz, SJ Liberman, I Juodawlkis, AS Tharnish, P Shi, JX Liotta, DC Coderre, JA Olson, J TI Treatment of isografted 9L rat brain tumors with beta-5-o-carboranyl-2 '-deoxyuridine neutron capture therapy SO CLINICAL CANCER RESEARCH LA English DT Article ID 5-CARBORANYL-2'-DEOXYURIDINE; GLIOMAS AB beta-5-o-Carboranyl-2'-deoxyuridine (D-CDU) is a nontoxic pyrimidine nucleoside analogue designed for boron neutron capture therapy of brain tumors. Irt vitro studies indicated that D-CDU accumulates to levels 92- and 117-fold higher than the extracellular concentration in rat 9L and human U-251 glioma cells, respectively, and persists for several hours at levels 5-fold higher than the extracellular concentration. Furthermore, D-CDU was not toxic to rats injected i.p. with up to 150 mg/kg, On the basis of these studies, D-CDU was evaluated as a neutron capture therapy agent using rats bearing stereotactically implanted intracranial 9L, tumors at single i.p. doses of 30 mg/kg and 150 mg/kg of D-CDU (20% B-10 enriched), given 2 h before irradiation with thermal neutrons, Boron concentrations in tumors 2 h after dosing were 2.3 +/- 1.6 and 7.4 +/- 1.3 Erg boron/g tissue (mean +/- SD), corresponding to tumor/brain ratios of 11.5 +/- 3.6 and 6.8 +/- 2.0 mu g boron/g tissue for the low and high doses, respectively. All untreated animals died within 28 days, whereas half survived at days 32, 55, and 38 for groups receiving neutrons only, 30 mg/kg D-CDU, and 150 mg/kg D-CDU, respectively. Odds ratios of all treatment groups differed significantly from the untreated group (P < 0.002; logrank test). The median survival time for the 30 mg/kg-treated group but not for the 150 mg/kg-treated group was significantly longer than for rats treated with neutrons only (P = 0.036), which may correlate with the decreased tumor selectivity for D-CDU observed at the higher dose. Additional pharmacodynamic studies are warranted to determine optimal dosing strategies for D-CDU. C1 Vet Affairs Med Ctr, Decatur, GA 30033 USA. Emory Univ, Sch Med, Biochem Pharmacol Lab, Dept Pediat, Atlanta, GA 30322 USA. Emory Univ, Sch Med, Biochem Pharmacol Lab, Dept Neurosurg, Atlanta, GA 30322 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Schinazi, RF (reprint author), Vet Affairs Med Ctr, 151H,1670 Clairmont Rd, Decatur, GA 30033 USA. RI Schinazi, Raymond/B-6777-2017 NR 18 TC 15 Z9 15 U1 0 U2 2 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 1078-0432 J9 CLIN CANCER RES JI Clin. Cancer Res. PD FEB PY 2000 VL 6 IS 2 BP 725 EP 730 PG 6 WC Oncology SC Oncology GA 287JK UT WOS:000085502600055 PM 10690559 ER PT J AU Davis, WC AF Davis, WC TI Complete equation of state for unreacted solid explosive SO COMBUSTION AND FLAME LA English DT Article AB A complete equation of state, based on a reference isentrope derived using the Walsh mirror image approximation, is discussed and calibrated for unreacted PBX9501. There are very few relevant data for the calibration, and the emphasis is on how calibration may be done rather than on presenting a final perfect equation of state. (C) 1999 by The Combustion Institute. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Davis, WC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 7 TC 14 Z9 15 U1 0 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 FEB PY 2000 VL 120 IS 3 BP 399 EP 403 DI 10.1016/S0010-2180(99)00112-1 PG 5 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 266VE UT WOS:000084320300012 ER PT J AU Jadach, S Ward, BFL Was, Z AF Jadach, S Ward, BFL Was, Z TI The Monte Carlo program KORALZ, for the lepton or quark pair production at LEP/SLC energies - From version 4.0 to version 4.04 SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE radiative corrections; heavy lepton tau; Monte Carlo simulation; quantum electrodynamics; spin polarization; electroweak theory; anomalous couplings ID QED RADIATIVE-CORRECTIONS; ELECTROWEAK; PHOTOS; DECAYS AB Brief information on new features of KORALZ version 4.04 with respect to version 4.0 is given. The main difference is that the new version could be used at LEP2 energies, i.e. up to 240 GeV centre-of-mass system energy. The possibility to switch on different classes of anomalous couplings is also included. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Inst Nucl Phys, Krakow, Poland. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Jadach, S (reprint author), CERN, Div Theory, CH-1211 Geneva 23, Switzerland. NR 21 TC 32 Z9 32 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 2000 VL 124 IS 2-3 BP 233 EP 237 DI 10.1016/S0010-4655(99)00437-3 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 282BF UT WOS:000085195400009 ER PT J AU Ng, EG Raghavan, P AF Ng, EG Raghavan, P TI Towards a scalable hybrid sparse solver SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article DE sparse matrix factorization; conjugate gradient; incomplete Cholesky; preconditioners ID SOLVING TRIANGULAR SYSTEMS; LINEAR-SYSTEMS; CHOLESKY FACTORIZATION; ALGORITHM; ELIMINATION; MATRIX; MULTIPROCESSORS; EQUATIONS AB Consider the solution of very large, sparse linear systems, The most popular techniques can be broadly classified as either 'direct' or 'iterative', When the sparse matrix is symmetric and positive definite, direct methods use Cholesky factorization while iterative methods rely on Conjugate Gradients, Our goal is to develop a scalable and memory-efficient hybrid of the two methods that can be implemented with high efficiency on both serial and parallel computers and be suitable for a wide range of problems. We discuss our overall design with emphasis on performance and scalability issues, and report on progress to date. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC Div, Berkeley, CA 94720 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. RP Ng, EG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC Div, 1 Cyclotron Rd,MS 50F, Berkeley, CA 94720 USA. NR 56 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 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD FEB-MAR PY 2000 VL 12 IS 2-3 BP 53 EP 68 PG 16 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 318RH UT WOS:000087297300002 ER PT J AU Oblonsky, LJ Ryan, MP Isaacs, HS AF Oblonsky, LJ Ryan, MP Isaacs, HS TI In situ XANES study of the formation and reduction of the passive film formed on Fe in acetate solution SO CORROSION SCIENCE LA English DT Article DE iron; acetate; XANES; in situ; reduction; galvanostatic; passive films ID X-RAY-ABSORPTION; CATHODIC REDUCTION; BORATE BUFFER; IRON; DISSOLUTION; MECHANISM AB In situ X-ray absorption near edge structure (XANES) was used to study the formation and galvanostatic reduction of passive films that form on Fe in 1 and 0.1 M acetate solutions of DH 4.5-7.5, Passivation at anodic potentials was accompanied by dissolution of Fe; a small amount of dissolution at pH 5.5-7.5 and significantly more dissolution at pH 4.5, Passive him thickness was approximately 40-50 Angstrom and did not vary with pH. Nevertheless, the duration of the potential decay during galvanostatic reduction at -1 mu A cm(-2) increased substantially with pH from 380 s at pH 4.5 to 2500 s at pH 7.5. At the knee of the potential decay curve, a burst of dissolution occurred where the reduced passive film and remainder of the metallic Fe sample dissolved. The plot of the plateau potential versus pH had a slope of -94 mV/pH unit. The products of the reduction were Fe3O4 and Fe2+. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Oblonsky, LJ (reprint author), Dupont Co, Cent Res & Dev, Expt Stn, POB 80323, Wilmington, DE 19880 USA. NR 19 TC 16 Z9 17 U1 2 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0010-938X J9 CORROS SCI JI Corrosion Sci. PD FEB PY 2000 VL 42 IS 2 BP 229 EP 241 DI 10.1016/S0010-938X(99)00078-5 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 281XH UT WOS:000085186400003 ER PT J AU Katkov, II AF Katkov, II TI A two-parameter model of cell membrane permeability for multisolute systems SO CRYOBIOLOGY LA English DT Article; Proceedings Paper CT World Congress of Cryobiology CY JUL 12-15, 1999 CL MARSEILLE, FRANCE DE membrane; permeability; modeling; osmotic response; volume excursions; multisolute systems; cryoprotectants AB A two-parameter model of cell osmotic response (F. W. Kleinhans, 1998, Cryobiology 37, 271-289) is expanded for multisolute systems. The cell water volume W and intracellular osmolalities of N solutes are related as W[1 + LpRT Sigma(i=1)(N)(M-i/P-i)] = W-o[1 + LpRT Sigma(i-1)(N)(M-o)i/P-i)], where M-i is the intracellular osmolality of the ith solute (i = 1... N), P-i is the membrane permeability of the ith solute, L-p is the membrane hydraulic conductivity, R is the gas constant, T is the absolute temperature, and the subscript "0" denotes the initial values at time zero. The above formula allows calculating the final (equilibrium) volume when all entities are permeable. Simple algebraic expressions for calculation of the number and magnitude of transient maximum volume excursions are presented. These simple expressions can all be calculated by hand on a pocket calculator. Practical examples of one-, two-, and three-solute systems are discussed. Special attention has been given to situations when systems contain an impermeable component. All formulas are simple to use for optimization of variety of cryobiological protocols. Application of the theory for optimization of addition and dilution of a permeable cryoprotectant is also discussed. (C) 2000 Academic Press. C1 Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA. RP Katkov, II (reprint author), Universal Preservat Technol Inc, Semen & Embryo Preservat Lab, 11045 Roselle St,Suite C, San Diego, CA 92121 USA. RI Katkov, Igor/D-7163-2015 OI Katkov, Igor/0000-0001-9251-0494 FU NIAID NIH HHS [R01-AI36243]; NICHD NIH HHS [R01-HD30274] NR 10 TC 33 Z9 35 U1 0 U2 7 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0011-2240 J9 CRYOBIOLOGY JI Cryobiology PD FEB PY 2000 VL 40 IS 1 BP 64 EP 83 DI 10.1006/cryo.1999.2226 PG 20 WC Biology; Physiology SC Life Sciences & Biomedicine - Other Topics; Physiology GA 292EZ UT WOS:000085782300008 PM 10679151 ER PT J AU Norby, RJ AF Norby, RJ TI Atmospheric CO2 and ecosystem feedback between C and N cycles: Synthesis of an integrated experiment SO ECOLOGICAL APPLICATIONS LA English DT Article DE atmospheric CO2; carbon cycling; fine root turnover; global change; nitrogen cycling; open-top chambers; Populus tremuloides; scale soil microorganisms; tree growth; trembling aspen C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Norby, RJ (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Norby, Richard/C-1773-2012 OI Norby, Richard/0000-0002-0238-9828 NR 0 TC 0 Z9 0 U1 2 U2 5 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD FEB PY 2000 VL 10 IS 1 BP 1 EP 2 DI 10.1890/1051-0761(2000)010[0001:ACAEFB]2.0.CO;2 PG 2 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 280NG UT WOS:000085108400001 ER PT J AU Martens, SN Breshears, DD Meyer, CW AF Martens, SN Breshears, DD Meyer, CW TI Spatial distributions of understory light along the grassland/forest continuum: effects of cover, height, and spatial pattern of tree canopies SO ECOLOGICAL MODELLING LA English DT Article DE canopy microclimate; photosynthetically active radiation; ray tracing; savanna; shading; solar radiation ID NORTHERN NEW-MEXICO; PHOTOSYNTHETICALLY ACTIVE RADIATION; PINYON-JUNIPER WOODLANDS; DISCONTINUOUS CANOPIES; SEMIARID WOODLAND; ASYMMETRIC CROWNS; PLANT-COMMUNITIES; SOLAR-RADIATION; FOREST CANOPIES; SOIL-MOISTURE AB The understory light environment is a key determinant of vegetation pattern and ecosystem processes, and varies spatially perhaps more than any resource used by plants. Understory light varies along gradients of vegetation structure that range from grassland with no woody canopy cover to forest with nearly complete woody canopy cover. Spatial variability in understory light is largely determined by several characteristics of overstory plants - spatial pattern, height, and cover - which vary concurrently along the grassland/forest continuum. Using a spatially-explicit ray-tracing model, we quantified trends in mean and variance of understory light along the continuum. We modeled understory light over a glowing season for two types of plots: (1) generated plots in which cover, spatial pattern, and height of trees were varied systematically, and (2) three actual plots using stand data from pinon-juniper woodland sites for which cover, spatial pattern and height varied concurrently. Mean understory light decreased with increasing canopy cover and was sensitive to changes in height, as expected, but was not sensitive to spatial pattern. Variance in understory light was maximum at an intermediate value of cover that was dependent on both spatial pattern and cover - maximum variance occurred at lower values of cover as height increased and as spatial pattern progressed from regular to random to aggregated. These trends in the overall patterns of understory light were also examined with respect to changes in understory light in canopy and intercanopy locations. Variance in understory light for intercanopy locations was less than that for canopy locations at low canopy cover? but exceeded that for canopy locations as canopy cover increased. The value of canopy cover at which variance in intercanopy locations exceeded that in canopy locations was sensitive to variation in height but not in spatial pattern. The distributions of understory light for the actual plots were generally similar to those for corresponding generated plots, with dissimilarities attributable to differences in cover and height. The general trends highlighted by our simulations are broadly applicable to sites along the grassland/forest continuum. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Environm Sci Grp, Los Alamos, NM 87545 USA. RP Breshears, DD (reprint author), Univ Calif Los Alamos Natl Lab, Environm Sci Grp, Mail Stop J495, Los Alamos, NM 87545 USA. RI Breshears, David/B-9318-2009 OI Breshears, David/0000-0001-6601-0058 NR 55 TC 109 Z9 121 U1 8 U2 44 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD FEB 1 PY 2000 VL 126 IS 1 BP 79 EP 93 DI 10.1016/S0304-3800(99)00188-X PG 15 WC Ecology SC Environmental Sciences & Ecology GA 282GR UT WOS:000085210300007 ER PT J AU Yang, XQ Sun, X McBreen, J AF Yang, XQ Sun, X McBreen, J TI New phases and phase transitions observed in Li1-xCoO2 during charge: in situ synchrotron X-ray diffraction studies SO ELECTROCHEMISTRY COMMUNICATIONS LA English DT Article DE synchroton; X-ray diffraction; Li1-xCoO2; LiCoO2; phase transition; lithium batteries ID LIXCOO2; CELLS AB We have utilized synchrotron X-ray radiation to perform an 'in situ' X-ray diffraction study on a Li1-xCoO2 cathode in a Li\Li1-xCoO2 cell. The cell was charged at a C/10 rate from 3.5 to 5.2 V. In the composition range of x=0 to x=0.5, a new intermediate phase H2a was observed in addition to the two expected hexagonal phases, H1 and H2. Ln the region very close to x=0.5, some spectral signatures for the formation of a monoclinic phase Mi were also observed. Furthermore, in the x=0.8 to x=1 region, the formation of a CdI2 type hexagonal phase has been confirmed. However, this new phase originates from a CdCl2 type hexagonal phase, rather than from a monoclinic phase M2 as previously reported in the Literature. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Yang, XQ (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 7 TC 55 Z9 61 U1 5 U2 52 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1388-2481 J9 ELECTROCHEM COMMUN JI Electrochem. Commun. PD FEB PY 2000 VL 2 IS 2 BP 100 EP 103 DI 10.1016/S1388-2481(99)00155-1 PG 4 WC Electrochemistry SC Electrochemistry GA 282CN UT WOS:000085198900008 ER PT J AU Wang, HM Boisvert, D Kim, KK Kim, R Kim, SH AF Wang, HM Boisvert, D Kim, KK Kim, R Kim, SH TI Crystal structure of a fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 angstrom resolution SO EMBO JOURNAL LA English DT Article DE crystal structure; fibrillarin; ribosome biogenesis; rRNA methylation; snoRNA ID SMALL NUCLEOLAR RNAS; RIBOSOMAL-RNA; S-ADENOSYLMETHIONINE; DEPENDENT METHYLTRANSFERASES; MOLECULAR-CLONING; PROTEIN; DNA; SEQUENCE; DOMAIN; YEAST AB Fibrillarin is a phylogenetically conserved protein essential for efficient processing of pre-rRNA through its association with a class of small nucleolar RNAs during ribosomal biogenesis. The protein is the antigen for the autoimmune disease scleroderma. Here we report the crystal structure of the fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 Angstrom resolution. The structure consists of two domains, with a novel fold in the N-terminal region and a methyltransferase-like domain in the C-terminal region. Mapping temperature-sensitive mutations found in yeast fibrillarin Nop1 to the Methanococcus homologue structure reveals that many of the mutations cluster in the core of the methyltransferase-like domain. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 51 TC 122 Z9 128 U1 0 U2 5 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0261-4189 J9 EMBO J JI Embo J. PD FEB 1 PY 2000 VL 19 IS 3 BP 317 EP 323 DI 10.1093/emboj/19.3.317 PG 7 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 281AB UT WOS:000085135000001 PM 10654930 ER PT J AU Vine, E Mills, E Chen, A AF Vine, E Mills, E Chen, A TI Energy-efficiency and renewable energy options for risk management and insurance loss reduction SO ENERGY LA English DT Article AB This paper identifies a spectrum of risk management opportunities associated with technologies and procedures that use energy more efficiently or supply renewable energy. While the economic benefits of these measures have long been of interest to energy consumers seeking to reduce their energy expenditures, we have found that they also offer a novel and largely untapped pathway for achieving traditional risk management objectives. These technologies have many benefits, including insurance loss reduction and prevention. Early examples of research in energy efficiency and renewable energy technologies conducted by insurers are described, and new interdisciplinary collaborative applied research is proposed. These technologies should be of interest to the insurance and risk management communities (e.g., researchers, insurance companies, government, energy service companies, facility owners, and utility companies). (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Vine, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg 90-2000, Berkeley, CA 94720 USA. NR 14 TC 7 Z9 7 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD FEB PY 2000 VL 25 IS 2 BP 131 EP 147 DI 10.1016/S0360-5442(99)00068-7 PG 17 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 287QB UT WOS:000085516200002 ER PT J AU Kaplan, DI Serne, RJ Parker, KE Kutnyakov, IV AF Kaplan, DI Serne, RJ Parker, KE Kutnyakov, IV TI Iodide sorption to subsurface sediments and illitic minerals SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID IRON-OXIDES; SOIL; EXCLUSION AB Laboratory studies were conducted to quantify and identify the key processes by which iodide (I-) sorbs to subsurface arid sediments. A surprisingly large amount of I- sorbed to three alkaline subsurface sediments that were low in organic matter content; distribution coefficients (K-d's) ranged from 1 to 10 mL/g and averaged 3.3 mL/g. Experiments with pure mineral isolates, similar to the minerals identified in the clay fraction of the sediments, showed that there was little or no I- sorption to calcite (K-d = 0.04 +/- 0.01 mL/g), chlorite (K-d = -0.22 +/- 0.06 mL/g), goethite (K-d = 0.10 +/- 0.03 mL/g), montmorillonite (K-d = -0.42 +/- 0.08 mL/g), quartz (K-d = 0.04 +/- 0.02 mL/g), or vermiculite (K-d = 0.56 +/- 0.21 mL/g). Conversely, a significant amount of I- sorbed to illite (K-d = 15.14 +/- 2.84 mL/g). Treating the I-125(-)- laden illite mixtures with dissolved F-, Cl-, Br-, or I-127(-), caused 43 +/- 3%, 45 +/- 0%, 52 +/- 3%, and 83 +/- 1%, respectively, of the adsorbed I- to desorb. Finally, I- sorption to illite was strongly pH-dependent; the K-d values decreased from 46 to 22 mL/g as the pH values increased from 3.6 to 9.4. An appreciable amount of I- sorbed to illite even under alkaline conditions. These experiments suggest that illite removed I- from the aqueous phase predominantly by reversible physical adsorption to the pH-dependent edge sites. Illites may constitute a substantial proportion of the clay-size fraction of many arid sediments and therefore may play an important role in retarding I- movement in these sediments. C1 Westinghouse Savannah River Co, Aiken, SC 29808 USA. Pacific NW Natl Lab, Richland, WA USA. RP Kaplan, DI (reprint author), Westinghouse Savannah River Co, Aiken, SC 29808 USA. NR 29 TC 65 Z9 68 U1 0 U2 17 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 FEB 1 PY 2000 VL 34 IS 3 BP 399 EP 405 DI 10.1021/es990220g PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 279ZL UT WOS:000085077100028 ER PT J AU Reyes, CA Medina, M Crespo-Hernandez, C Cedeno, MZ Arce, R Rosario, O Steffenson, DM Ivanov, IN Sigman, ME Dabestani, R AF Reyes, CA Medina, M Crespo-Hernandez, C Cedeno, MZ Arce, R Rosario, O Steffenson, DM Ivanov, IN Sigman, ME Dabestani, R TI Photochemistry of pyrene on unactivated and activated silica surfaces SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; CRINIPELLIS-STIPITARIA; GEL/AIR INTERFACE; FLY-ASH; PHOTOPHYSICS; PHOTOLYSIS; GEL; IDENTIFICATION; SPECTROSCOPY; SIO2 AB Photolysis of pyrene at the solid/air interface of unactivated and activated silica gel proceeds slowly to give mainly oxidized pyrene products. We have identified 1-hydroxypyrene, 1,6-pyrenedione, and 1,8-pyrenedione among the main reaction products. The remaining minor products show molecular weights and spectral properties consistent with oxygenated pyrenes. Furthermore, small amounts of 1,1'-bipyrene dimer are also formed at higher surface coverages (2 x 10(-5) mol/g). When photolysis is carried out at 5 x 10(-5) mol/g pyrene, photodegradation rate drops sharply and pyrene loss becomes insignificant. No significant change in the product distribution is observed when the photolysis is carried out on unactivated or activated silica. Photodegradation rate is slightly faster on activated silica comp a red to unactivated silica. Mechanistic studies indicate that the precursor to photoproduct formation is pyrene cation radical which is postulated to be formed by electron transfer from pyrene excited state to oxygen (type I) or by photoionization of pyrene. The cation radical reacts with physisorbed water on silica to give the observed oxidation products. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Univ Puerto Rico, Dept Chem, Rio Piedras, PR 00931 USA. RP Dabestani, R (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI Crespo-Hernandez, Carlos/A-9915-2008; ivanov, ilia/D-3402-2015 OI Crespo-Hernandez, Carlos/0000-0002-3594-0890; ivanov, ilia/0000-0002-6726-2502 NR 49 TC 60 Z9 61 U1 2 U2 15 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 FEB 1 PY 2000 VL 34 IS 3 BP 415 EP 421 DI 10.1021/es9905391 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 279ZL UT WOS:000085077100030 ER PT J AU Liu, W Vidic, RD Brown, TD AF Liu, W Vidic, RD Brown, TD TI Optimization of high temperature sulfur impregnation on activated carbon for permanent sequestration of elemental mercury vapors SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GAS-PHASE MERCURY AB Following previous success with the use of activated carbon impregnated with sulfur at elevated temperatures for elemental mercury control, possible improvements in the impregnation procedure were evaluated in this study. Adsorbents prepared by thoroughly mixing sulfur and activated carbon in the furnace at the initial sulfur-to-carbon ratio (SCR) ranging from 4:1 to 1:2 showed similar adsorptive behavior in a fixed-bed system. Maintaining a stagnant inert atmosphere during the impregnation process improves sulfur deposition resulting in the enhanced dynamic capacity of the adsorbent when compared to other sulfur impregnated carbons. The fate of spent adsorbents was assessed using a toxicity characteristics leaching procedure (TCLP). Although mercury concentration in all leachates was below the TCLP limit (0.2 mg/L), virgin activated carbon lost a significant fraction of the adsorbed elemental mercury during storage, while no loss was observed for sulfur-impregnated carbons. This finding suggests that virgin activated carbon may not be appropriate adsorbent for permanent sequestration of anthropogenic elemental mercury emissions. C1 Univ Pittsburgh, Dept Civil & Environm Engn, Pittsburgh, PA 15261 USA. US DOE, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. RP Vidic, RD (reprint author), Univ Pittsburgh, Dept Civil & Environm Engn, 943 Benedum Hall, Pittsburgh, PA 15261 USA. OI Vidic, Radisav/0000-0001-7969-6845 NR 12 TC 46 Z9 49 U1 3 U2 17 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 FEB 1 PY 2000 VL 34 IS 3 BP 483 EP 488 DI 10.1021/es9813008 PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 279ZL UT WOS:000085077100040 ER PT J AU Chesser, RK Sugg, DW Lomakin, MD Van den Bussche, RA DeWoody, JA Jagoe, CH Dallas, CE Whicker, FW Smith, MH Gaschak, SP Chizhevsky, IV Lyabik, VV Buntova, EG Holloman, K Baker, RJ AF Chesser, RK Sugg, DW Lomakin, MD Van den Bussche, RA DeWoody, JA Jagoe, CH Dallas, CE Whicker, FW Smith, MH Gaschak, SP Chizhevsky, IV Lyabik, VV Buntova, EG Holloman, K Baker, RJ TI Concentrations and dose rate estimates of (134,137)cesium and (90)strontium in small mammals at Chornobyl, Ukraine SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Chornobyl; Chernobyl; dose; cesium; strontium ID CHERNOBYL ACCIDENT; POWER-PLANT; POPULATIONS; RADIATION; VICINITY AB Free-ranging mammals near the Chornobyl nuclear reactor are experiencing substantial radiation dose rates from intramuscular concentrations of Cs-134,Cs-137 and skeletal Sr-90. Radiocesium concentrations averaged 3,200 Bq/g of dry muscle, compared to a mean of 297 Bq Sr-90/g in bone for mammals in the Exclusion Zone, a region of restricted human activity surrounding the reactor. Estimates of dose rates from intramuscular sources of radiocesium averaged 2.4 mGy/d within 8 km of the reactor and ranged as high as 60 mGy/d. Overall dose rates from internal Sr-90 for mammals in the Exclusion Zone averaged 1.0 mGy/d, although doses to specific tissues are likely much higher. Mammals captured 30 km southeast of the reactor averaged only 2 Bq/g of muscle and were receiving an average of 1.4 mu Gy/d from internal radiocesium. Dramatic Variation exists in the spatial pattern of radiocesium in areas immediately surrounding the reactor and within and between remediated and unremediated regions. The variance of Sr-90 for taxa among sites was significantly less than that for Cs-134,Cs-137. Thermoluminescent dosimeters placed on free-ranging mice showed that dose rates from external sources of radiation were much greater than the dose rates from internal sources of radiocesium. Estimated dose rates in very small areas of the Chornobyl region exceed those reported to impede reproductive success in mammals. C1 Univ Georgia, Dept Genet, Athens, GA 30602 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. Int Res & Dev Agcy, UA-252001 Kiev, Ukraine. Texas Tech Univ, Dept Biol Sci, Lubbock, TX 79409 USA. Oklahoma State Univ, Dept Zool, Stillwater, OK 74078 USA. Univ Georgia, Dept Pharmacol & Toxicol, Athens, GA 30602 USA. Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. Chornobyl Sci & Tech Ctr Int Res, Chornobyl, Ukraine. RP Chesser, RK (reprint author), Univ Georgia, Dept Genet, Athens, GA 30602 USA. RI DeWoody, James/C-4909-2008 OI DeWoody, James/0000-0002-7315-5631 NR 42 TC 54 Z9 56 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 FEB PY 2000 VL 19 IS 2 BP 305 EP 312 DI 10.1897/1551-5028(2000)019<0305:CADREO>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 294ZW UT WOS:000085941900009 ER PT J AU McCarthy, JF Southworth, GR Ham, KD Palmer, JA AF McCarthy, JF Southworth, GR Ham, KD Palmer, JA TI Time-integrated, flux-based monitoring using semipermeable membrane devices to estimate the contribution of industrial facilities to regional polychlorinated biphenyl budgets SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE semipermeable membrane devices; polychlorinated biphenyls; principle components analysis; surface water; budget ID POLYCYCLIC AROMATIC-HYDROCARBONS; ORGANIC CONTAMINANTS; RIVER; WATER; ACCUMULATION; RESIDUES AB Passive monitoring of polychlorinated biphenyls (PCB) using semipermeable membrane devices (SPMD) was employed to evaluate the contribution of point and nonpoint sources to the Bur of PCB in a drainage system encompassing three U.S. Department of Energy (U.S. DOE) industrial and research facilities in eastern Tennessee, USA. Polychlorinated biphenyls concentrations were highest at outfalls containing process waste from the DOE industrial facilities. The significance of these releases was evaluated by calculating the PCB flux (mass per unit time) at different monitoring locations. The Bur was calculated from the time-integrated estimates of the aqueous concentrations of PCB and estimates of the volumetric flow rates of discharges and receiving streams during the deployment period. The DOE discharges accounted for most of the flux of PCB entering the Clinch River from the DOE drainage areas, but these sources constituted only 10% of the flux in the Clinch River about the DOE sources. Principal components analysis was helpful in attributing sources of PCB. In a stream receiving multiple inputs of PCB, congener profiles from upstream sources and discrete discharges were consistent with a mixture of those congener profiles in the downstream receiving water. In another stream with a single upstream source of PCB, changes in PCB Aux and congener profiles suggested an apparent steady-state distribution between dissolved PCB and PCB adsorbed to organic matter on the streambed. The flux of dissolved PCB along different stream reaches reflected changes in the sediment organic content. Subtle alterations in congener profiles moving downstream suggested preferential desorption of less chlorinated congeners and sorption of mon highly chlorinated congeners to sediment. Time-integrated flux-based monitoring can be useful across a range of spatial scales for evaluating the significance of point and nonpoint contaminant sources and can help identify and prioritize feasible remedial alternatives. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Washington Dept Fish & Wildlife, Ellensburg, WA 98926 USA. RP McCarthy, JF (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 26 TC 14 Z9 14 U1 0 U2 3 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 FEB PY 2000 VL 19 IS 2 BP 352 EP 359 DI 10.1897/1551-5028(2000)019<0352:TIFBMU>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 294ZW UT WOS:000085941900015 ER PT J AU Palmedo, H Guhlke, S Bender, H Sartor, J Schoeneich, G Risse, J Grunwald, F Knapp, FF Biersack, HJ AF Palmedo, H Guhlke, S Bender, H Sartor, J Schoeneich, G Risse, J Grunwald, F Knapp, FF Biersack, HJ TI Dose escalation study with rhenium-188 hydroxyethylidene diphosphonate in prostate cancer patients with osseous metastases SO EUROPEAN JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE prostate cancer; painful bone metastases; rhenium-188 hydroxyethylidene diphosphonate haematotoxicity; dose escalation ID PAINFUL BONE METASTASES; RE-186 HEDP; THERAPY; SR-89; PALLIATION; PLACEBO; TRIAL AB The aim of this study was to determine the maximum tolerated dose of rhenium-188 hydroxyethylidene diphosphonate (HEDP) in prostate cancer patients with osseous metastases who are suffering from bone pain, Twenty-two patients received a single injection of escalating doses of carrier-added Re-188-HEDP [1.3 GBq (35 mCi), 2.6 GBq (70 mCi), 3.3 GBq (90 mCi) and 4.4 GBq (120 mCi)]. Blood counts and biochemical parameters were measured weekly over a period of 8 weeks. Haematological toxicity (WHO grading) of grade 3 or 4 was considered unacceptable. Clinical follow-up studies including methods of pain documentation (medication, pain diary) were performed for 6 months after treatment, In the 1.3-GBq group. no haematological toxicity was observed. First haematotoxic results were noted in those patients with a dose of 2.6 GBq Re-188-HEDP. In the 3.3-GBq group, one patient showed a reversible thrombopenia of grade 1, one a reversible thrombopenia of grade 2 and three a reversible leukopenia of grade 1. In the 4.4-GBq group, thrombopenia of grades 3 and 4 was observed in one and two patients (baseline thrombocyte count <200 x 10(9)/l), respectively, and leukopenia of grade 3 was documented in one patient. The overall nadir of thrombopenia was at week 4. The individual, maximum percentage decrease in thrombocytes in the 1.3-, 2.6-, 3.3- and 4.4-GBq groups was 17%, 40%, 60% and 86%, respectively. In two patients, a transient increase in serum creatinine was observed (max, 1.6 mg/dl). Pain palliation was reported by 64% of patients, with a mean duration of 7.5 weeks. The response rate seemed to increase with higher doses, reaching 75% in the 4.4-GBq group, It is concluded that in prostate cancer patients, the maximum tolerated dose of Re-188-HEDP is 3.3 GBq if the baseline thrombocyte count is below 200x10(9)/l, In patients with thrombocyte counts significantly above 200x10(9)/1, a dose of 4.4 GBq might be tolerable, Thrombo- and leukopenia are the most important side-effects, Pain palliation can be achieved in 60%-75% of patients receiving a dose of 2.6 GBq or more of Re-188-HEDP. Studies in a larger patient population are warranted to evaluate further the palliative effect of Re-188-HEDP. C1 Univ Bonn, Dept Nucl Med, D-53127 Bonn, Germany. Univ Bonn, Dept Urol, D-53127 Bonn, Germany. Oak Ridge Natl Lab, Nucl Med Grp, Oak Ridge, TN USA. RP Palmedo, H (reprint author), Univ Bonn, Dept Nucl Med, Siegmund Freud Str 25, D-53127 Bonn, Germany. NR 20 TC 84 Z9 91 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-6997 J9 EUR J NUCL MED JI Eur. J. Nucl. Med. PD FEB PY 2000 VL 27 IS 2 BP 123 EP 130 DI 10.1007/s002590050017 PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 286UZ UT WOS:000085468400002 PM 10755716 ER PT J AU Korgul, A Urban, W Rzaca-Urban, T Rejmund, M Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Schulz, N Bentaleb, M Lubkiewicz, E Ahmad, I Morss, LR AF Korgul, A Urban, W Rzaca-Urban, T Rejmund, M Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Schulz, N Bentaleb, M Lubkiewicz, E Ahmad, I Morss, LR TI Properties of N=84, even-even nuclei populated in the spontaneous fission of Cm-248 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID HIGH-SPIN STATES; PRODUCT GAMMA-RAY; SHELL-MODEL; NEUTRON-RICH; OCTUPOLE COLLECTIVITY; SINGLE-PARTICLE; SN-132 REGION; EXCITATIONS; SPECTROSCOPY; ND-144 AB Excited states in the neutron-rich, N=84 nuclei Sn-134, Te-136 and Xe-138, populated in the spontaneous fission of Cm-248, Were Studied to medium spins using the EUROGAM2 array. OXBASH code calculations support the experimental identification of maximum aligned configurations in these isotopes. Empirical shell model calculations agree with the proposed excitation energy of the neutron h(9/2) excitation in the Sn-132 region. A discrepancy bct it een the observed and calculated excitation energy of the I-pi=12(+) level in Te-136 indicates possible admixtures of collective excitations in this nucleus. Clear signs of collective excitations are observed in Xe-138. C1 Univ Warsaw, Inst Phys Expt, PL-00681 Warsaw, Poland. Ctr Spectrometrie Nucl & Spectrometrie Masse, F-91405 Orsay, France. Univ Manchester, Dept Phys & Astron, Schuster Lab, Manchester M13 9PL, Lancs, England. IN2P3, CNRS, Inst Rech Subatom, F-67037 Strasbourg, France. Univ Strasbourg, F-67037 Strasbourg, France. Argonne Natl Lab, Argonne, IL 60439 USA. RP Univ Warsaw, Inst Phys Expt, Ul Hoza 69, PL-00681 Warsaw, Poland. NR 36 TC 58 Z9 58 U1 0 U2 6 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6001 EI 1434-601X J9 EUR PHYS J A JI Eur. Phys. J. A PD FEB PY 2000 VL 7 IS 2 BP 167 EP 176 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 338XE UT WOS:000088447900004 ER PT J AU Ciftja, O AF Ciftja, O TI The Fermi-sea-like limit of the composite fermion wave function SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID FILLED LANDAU-LEVEL; INCOMPRESSIBLE QUANTUM FLUID; STATES; APPROXIMATION; EXCITATIONS AB The experimentally observed filling factors of the fractional quantum Hall effect can be described in terms of the composite fermion wave function of the Jastrow-Slater form Psi(nu=p/(2mp+1))(CF) = (P) over cap(LLL)Pi(j 200 GeV2, have been measured with the ZEUS detector at HERA. A data sample of 47.7 pb(-1), collected at a center-of-mass energy of 300 GeV, has been used. The double-differential cross-section d sigma/dQ(2) falls by a factor of about 50000 as Q(2) increases from 280 to 30000 GeV2. The double differential cross section d(2)sigma/dxdQ(2) has also been measured. A comparison between the data and Standard Model (SM) predictions shows that contributions from antiquarks ((u) over bar and (c) over bar) and quarks (d and s) are both required by the data. The predictions of the SM give a good description of the full body of the data presented here. A comparison of the charged-current cross-section d sigma/dQ(2) with the recent ZEUS results for neutral-current scattering shows that the weak: and electromagnetic forces have similar strengths for Q(2) above M-W(2), M-Z(2). A fit to the data for d sigma/dQ(2) with the Fermi constant G(F) and M-W as free parameters yields G(F) = (1.171 +/- 0.034 (stat.)(-0.032)(+0.026) (syst.) (+0.016)(-0.015)(PDF)) x 10(-5) GeV-2 and M-W = 80.8(-4.5)(+4.9) (stat.) (+5.0)(-4.3) (syst.) (+1.4)(-1.3) (PDF) GeV. Results for M-W, where the propagator effect alone or the SM constraint between G(F) and M-W have been considered, are also presented. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Lab, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, D-2000 Hamburg, Germany. DESY Zeuthen, Zeuthen, Germany. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Expt Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Imperial Coll London, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, D-5170 Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. Univ Amsterdam, Amsterdam, Netherlands. NIKHEF, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford, England. Ist Nazl Fis Nucl, Padua, Italy. Univ Padua, Dipartimento Fis, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Ist Nazl Fis Nucl, Rome, Italy. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-57068 Siegen, Germany. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Turin, Fac Sci 2, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. IROE, Florence, Italy. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Graciani Diaz, Ricardo/I-5152-2016; Doyle, Anthony/C-5889-2009; Capua, Marcella/A-8549-2015; De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Hernandez Calama, Jose Maria/H-9127-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016; Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012 OI Graciani Diaz, Ricardo/0000-0001-7166-5198; Bailey, David C/0000-0002-7970-7839; Kasemann, Matthias/0000-0002-0429-2448; Doyle, Anthony/0000-0001-6322-6195; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Arneodo, Michele/0000-0002-7790-7132; Abbiendi, Giovanni/0000-0003-4499-7562; De Pasquale, Salvatore/0000-0001-9236-0748; Katz, Uli/0000-0002-7063-4418; Hernandez Calama, Jose Maria/0000-0001-6436-7547; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240; dusini, stefano/0000-0002-1128-0664 NR 61 TC 62 Z9 62 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 2000 VL 12 IS 3 BP 411 EP 428 DI 10.1007/s100529900280 PG 18 WC Physics, Particles & Fields SC Physics GA 295JM UT WOS:000085963000004 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 Case, T Cramer, O Crowe, KM Degener, T Doser, M Dunnweber, W Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Holzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Rothel, W 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 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 Case, T Cramer, O Crowe, KM Degener, T Doser, M Dunnweber, W Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Holzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Rothel, W 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 CA Crystal Barrel Collaboration TI (p)over-bar-p-annihilation into omega pi(0), omega eta and omega eta ' at 600, 1200 and 1940 MeV/c SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article AB The annihilation channels (p) over bar p-->omega pi(o), omega eta, omega eta' were studied with the CRYSTAL BARREL detector at LEAR at (p) over bar-momenta of 600, 1200, and 1940 MeV/c. In most cases angular distributions were measured which allowed a complete J(P)-analysis using the helicity formalism. The contribution of all relevant initial states could be determined. The maximal contributing angular moments are dependent on the (p) over bar-momentum and range up to J = 5. C1 Univ Karlsruhe, D-76021 Karlsruhe, Germany. Univ Hamburg, D-22761 Hamburg, Germany. CERN, CH-1211 Geneva, Switzerland. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Bonn, D-53115 Bonn, Germany. Hungarian Acad Sci, H-1525 Budapest, Hungary. Univ Bochum, D-44788 Bochum, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Queen Mary Univ London, London E1 4NS, England. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Munich, D-85748 Munich, Germany. Univ Paris 06, LPNHE, F-75252 Paris, France. Univ Paris 07, LPNHE, 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 OI Peters, Klaus/0000-0001-7133-0662 NR 9 TC 6 Z9 6 U1 0 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 2000 VL 12 IS 3 BP 429 EP 439 DI 10.1007/s100529900270 PG 11 WC Physics, Particles & Fields SC Physics GA 295JM UT WOS:000085963000005 ER PT J AU Burakovsky, L Page, PR AF Burakovsky, L Page, PR TI Tensor glueball-meson mixing phenomenology SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID DECAYS; STATES; MODEL; EXCITATIONS; XI(2230) AB The overpopulated isoscalar tensor states are sifted using Schwinger-type mass relations. TWO solutions are found: one Where the glueball is the f(J)(2220), and one where the glueball is more distributed, with f(2)(1820) having the largest component. The f(2)(1565) and f(J)(1710) cannot be accommodated as glueball-(hybrid) meson mixtures in the absense of significant coupling to decay channels. f(2)'(1525) --> pi pi is in agreement with experiment. The f(J)(2220) decays neither flavour democratically nor is narrow. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Theoret, MS-B283,POB 1663, Los Alamos, NM 87545 USA. EM burakov@t5.lanl.gov; prp@lanl.gov RI Page, Philip/L-1885-2015 OI Page, Philip/0000-0002-2201-6703 NR 62 TC 21 Z9 21 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 2000 VL 12 IS 3 BP 489 EP 498 DI 10.1007/s100529900281 PG 10 WC Physics, Particles & Fields SC Physics GA 295JM UT WOS:000085963000011 ER PT J AU Carena, M Ellis, J Lola, S Wagner, CEM AF Carena, M Ellis, J Lola, S Wagner, CEM TI Neutrino masses, mixing angles and the unification of couplings in the MSSM SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID SUPERSYMMETRIC STANDARD MODEL; GRAND UNIFIED THEORIES; INFRARED FIXED-POINT; TOP-QUARK MASS; ELECTROWEAK SYMMETRY-BREAKING; FERMION MASSES; YUKAWA TEXTURES; FAMILY SYMMETRY; SO(10) UNIFICATION; GAUGE SYMMETRIES AB In the light of the gathering evidence for nu(mu)-nu(tau) neutrino oscillations, coming in particular from the Super-Kamiokande data on atmospheric neutrinos, we re-analyze the unification of gauge and Yukawa couplings within the minimal supersymmetric extension of the Standard Model (MSSM). Guided by a range of different grand-unified models, we stress the relevance of large mixing in the lepton sector for the question of bottom-tau Yukawa coupling unification. We also discuss the dependence of the favoured value of tan beta on the characteristics of the high-energy quark and lepton mass matrices. In particular, we find that, in the presence of large lepton mixing, Yukawa unification can be achieved for intermediate Values of tan beta that were previously disfavoured. The renormalization-group sensitivity to the structures of different mass matrices may enable Yukawa unification to serve as a useful probe of GUT models. C1 CERN, Div Theory, CH-1211 Geneva, Switzerland. Argonne Natl Lab, Argonne, IL 60439 USA. RP Carena, M (reprint author), CERN, Div Theory, CH-1211 Geneva, Switzerland. RI Lola, Smaragda/L-6442-2014 OI Lola, Smaragda/0000-0002-1792-1856 NR 84 TC 34 Z9 34 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 2000 VL 12 IS 3 BP 507 EP 520 DI 10.1007/s100529900262 PG 14 WC Physics, Particles & Fields SC Physics GA 295JM UT WOS:000085963000013 ER PT J AU Gall, K Yang, N Horstemeyer, M McDowell, DL Fan, J AF Gall, K Yang, N Horstemeyer, M McDowell, DL Fan, J TI The influence of modified intermetallics and Si particles on fatigue crack paths in a cast A356 Al alloy SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE cast Al-Si alloy; fatigue crack propagation; silicon and intermetallic particles ID ALUMINUM-ALLOYS; AL-7SI-0.3MG ALLOY; FRACTURE-TOUGHNESS; SILICON PARTICLES; BEHAVIOR; LIFE; GROWTH; ADDITIONS; POROSITY; DEFECTS AB Mechanical fatigue tests were conducted on uniaxial specimens machined from a cast A356-T6 aluminium alloy plate at total strain amplitudes ranging from 0.1 to 0.8% (R = - 1). The cast alloy contains strontium-modified silicon particles (vol. fract. similar to 6%) within an AI-Si eutectic, dispersed a intermetallic particles, Al-15 (Fe,Mn)(3)Si-2 (vol. fract. similar to 1%), and an extremely low overall volume fraction of porosity (0.01%). During the initial stages of the fatigue process, we observed that a small semicircular fatigue crack propagated almost exclusively through the Al-1% Si dendrite cells. The small crack avoided the modified silicon particles in the Al-Si eutectic and only propagated along the a intermetallics if they were directly in line with the crack plane. These growth characteristics were observed up to a maximum stress intensity factor of similar to K-max(tr) = 7.0 MPa m(1/2) (maximum plastic zone size of 96 mu m). When the fatigue crack propagated with a maximum crack tip driving force above 7.0 MPa m(1/2) the larger fatigue crack tip process zone fractured an increased number of silicon particles and alpha intermetallics ahead of the crack tip, and the crack subsequently propagated preferentially through the damaged regions. As the crack tip driving force further increased, the area fraction of damaged alpha intermetallics and silicon particles on the fatigue fracture surfaces also increased. The final stage of failure (fast fracture) was observed to occur almost exclusively through the A-Si eutectic regions and the alpha intermetallics. C1 Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94550 USA. Georgia Inst Technol, Sch Mech Engn, GWW, Atlanta, GA 30332 USA. RP Gall, K (reprint author), Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94550 USA. NR 41 TC 44 Z9 50 U1 1 U2 9 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD FEB PY 2000 VL 23 IS 2 BP 159 EP 172 PG 14 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 300UZ UT WOS:000086272700008 ER PT J AU Dozortsev, D Coleman, A Nagy, P Diamond, MP Ermilov, A Weier, U Liyanage, M Reid, T AF Dozortsev, D Coleman, A Nagy, P Diamond, MP Ermilov, A Weier, U Liyanage, M Reid, T TI Nucleoli in a pronuclei-stage mouse embryo are represented by major satellite DNA of interconnecting chromosomes SO FERTILITY AND STERILITY LA English DT Article; Proceedings Paper CT XVI World Congress on Fertility and Sterility / 54th Annual Meeting of the American-Society-for-Reproductive-Medicine CY OCT 03-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Reprod Med, Int Federat Fertil & Steril DE zygote; nucleoli; alpha-satellite; centromeres; telomeres ID CHROMATIN; HYBRIDIZATION; ARRANGEMENTS; ASSOCIATION; INSITU; CELLS AB Objective: To investigate the arrangement of chromosomes within pronuclei-stage mouse zygotes. Design: In vitro study. Setting: Academic medical center. Patient(s): None. Intervention(s): None. Main Outcome Measure(s): Location of major alpha-satellite DNA, centromeres, and telomeres, and relative location of chromosomes. Result(s): Chromosomes appeared to be oriented inward by centromeres and to be interconnected by major alpha-satellite DNA, which appeared to be the sole DNA component of the nucleoli. This chromosomal arrangement persisted throughout interphase. Chromosomal painting failed to identify chromosomal ordering within pronuclei. Conclusion(s): Pronuclear nucleoli are represented by alpha-satellite sequences of interconnecting chromosomes that hold all chromosomes together during interphase. Chromosomes within the pronucleus are randomly positioned relative to each other. (Fertil Steril(R) 2000;73:366-71. (C)2000 by American Society for Reproductive Medicine.). C1 Wayne State Univ, Dept Obstet & Gynecol, Div Reprod Endocrinol, Detroit, MI USA. European Hosp, Rome, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NCI, Genet Lab, Div Basic Sci, Bethesda, MD 20892 USA. NIH, Genome Technol Branch, Natl Human Genome Res Inst, Bethesda, MD 20892 USA. RP Dozortsev, D (reprint author), Hutzel Hosp, Dept Obstet & Gynecol, 4707 St Antoine Blvd, Detroit, MI 48201 USA. OI Diamond, Michael/0000-0001-6353-4489 NR 19 TC 15 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0015-0282 J9 FERTIL STERIL JI Fertil. Steril. PD FEB PY 2000 VL 73 IS 2 BP 366 EP 371 DI 10.1016/S0015-0282(99)00491-4 PG 6 WC Obstetrics & Gynecology; Reproductive Biology SC Obstetrics & Gynecology; Reproductive Biology GA 281UF UT WOS:000085178600031 PM 10685545 ER PT J AU Cai, J Liu, HL Hu, Y Prausnitz, JM AF Cai, J Liu, HL Hu, Y Prausnitz, JM TI Critical properties of polydisperse fluid mixtures from an equation of state SO FLUID PHASE EQUILIBRIA LA English DT Article DE continuous thermodynamics; critical point; spinodal; equation of state ID LIQUID-LIQUID EQUILIBRIA; CONTINUOUS THERMODYNAMICS; PHASE-EQUILIBRIA; PRIMITIVE MODELS; MOLECULAR THEORY; BINARY-MIXTURES; STABILITY; WATER; POLYMERS; METHANOL AB Based on stability theory for polydisperse fluid mixtures, expressions have been developed for the spinodal criterion, critical criterion and various stability tests for systems containing one discrete component and one continuous homologue. Each criterion can be separated into two parts: the first part is the same in form as that for binary systems; when we assume particular mixing rules for parameters of the equation of state, that part is determined only by the average molar mass of the homologue. The second part is concerned with the distribution function that characterizes the continuous component. To illustrate results, the van der Waals equation of state is used to calculate critical properties; the composition dependences of parameters a(1/2) and b of the van der Waals equation are assumed to be linear functions of molar mass. Numerical results for the critical loci are obtained. For a discrete component j and a continuous component j, systematic variations of parameters in the distribution function for j or of the interaction parameter n(ij) Show transitions between qualitatively different types of phase behavior. (C) 2000 Elsevier Science B.V. All rights reserved. C1 E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Hu, Y (reprint author), E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China. EM yinghu@ecust.edu.cn NR 25 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD FEB 1 PY 2000 VL 168 IS 1 BP 91 EP 106 DI 10.1016/S0378-3812(99)00330-1 PG 16 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 293TM UT WOS:000085869500006 ER PT J AU Peshkin, M AF Peshkin, M TI Comment on "Quantum phase shift caused by spatial confinement" by B. E. Allman et al. SO FOUNDATIONS OF PHYSICS LETTERS LA English DT Editorial Material DE interferometry; phase shifts; force-free effects ID NEUTRONS AB The analysis of phase: shifts in executed and proposed interferometry experiments on photons and neutrons neglected forces exerted at: the boundaries of spatial constrictions. When those forces are included it is seen that the observed. phenomena, are not, in fact geometric in nature. A new proposal in the reply to this comment avoids that pitfall. C1 Argonne Natl Lab, Phys Div 203, Argonne, IL 60439 USA. RP Peshkin, M (reprint author), Argonne Natl Lab, Phys Div 203, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 9 TC 0 Z9 0 U1 1 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0894-9875 J9 FOUND PHYS LETT JI Found. Phys. Lett. PD FEB PY 2000 VL 13 IS 1 BP 97 EP 100 DI 10.1023/A:1007777821508 PG 4 WC Physics, Multidisciplinary SC Physics GA 310ZF UT WOS:000086859100009 ER PT J AU Becker, P Meinzer, FC Wullschleger, SD AF Becker, P Meinzer, FC Wullschleger, SD TI Hydraulic limitation of tree height: a critique SO FUNCTIONAL ECOLOGY LA English DT Review ID RAIN-FOREST TREES; TROPICAL FOREST; WATER RELATIONS; STOMATAL CONDUCTANCE; STAND DEVELOPMENT; PINUS-CONTORTA; ACER-SACCHARUM; CANOPY TREES; LIFE-HISTORY; FOLIAGE AREA C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Brunei Darussalam, Dept Biol, BE-1410 Gadong, Brunei. Hawaii Agr Res Ctr, Aiea, HI 96701 USA. RP Wullschleger, SD (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Wullschleger, Stan/B-8297-2012; Meinzer, Frederick/C-3496-2012 OI Wullschleger, Stan/0000-0002-9869-0446; NR 76 TC 95 Z9 103 U1 7 U2 29 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0269-8463 J9 FUNCT ECOL JI Funct. Ecol. PD FEB PY 2000 VL 14 IS 1 BP 4 EP 11 DI 10.1046/j.1365-2435.2000.00397.x PG 8 WC Ecology SC Environmental Sciences & Ecology GA 300BG UT WOS:000086232500002 ER PT J AU Beck, CW Congdon, JD AF Beck, CW Congdon, JD TI Effects of age and size at metamorphosis on performance and metabolic rates of Southern Toad, Bufo terrestris, metamorphs SO FUNCTIONAL ECOLOGY LA English DT Article DE Aerobic metabolism; complex life cycles; larval environment; larval period ID LIFE-HISTORY; LARVAL DENSITY; FROGS; FITNESS AB 1. Southern Toad, Bufo terrestris, tadpoles were reared at two temperatures and two food levels in a 2 x 2 factorial design. Effects of treatments on age and size at metamorphosis, metabolic rate (MR), sprint speed and endurance of metamorphs were measured. 2. Across all treatments, MR, sprint speed and endurance were negatively related to age at metamorphosis and positively related to mass at metamorphosis. Therefore, decreases in larval period duration and increases in mass at metamorphosis may be advantageous in terms of locomotor performance, but disadvantageous because of the cost of increased energy expenditure on maintenance, all else being equal. 3. After removing the effects of age and size at metamorphosis, neither of the treatments nor their interaction significantly affected locomotor performance. In contrast, MRs of metamorphs were significantly affected by the interaction between the food and temperature treatments, independent of age and size at metamorphosis. Thus, aspects of the larval environment may affect metamorph physiology, and possibly fitness, via mechanisms other than differences in age and size at metamorphosis. C1 Univ Georgia, Inst Ecol, Athens, GA 30602 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Beck, CW (reprint author), Emory Univ, Dept Biol, Atlanta, GA 30322 USA. NR 22 TC 65 Z9 69 U1 0 U2 27 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0269-8463 J9 FUNCT ECOL JI Funct. Ecol. PD FEB PY 2000 VL 14 IS 1 BP 32 EP 38 DI 10.1046/j.1365-2435.2000.00386.x PG 7 WC Ecology SC Environmental Sciences & Ecology GA 300BG UT WOS:000086232500005 ER PT J AU Tonn, BE AF Tonn, BE TI Ensuring the future SO FUTURES LA English DT Article AB Can intelligent life overcome a host of self-inflicted problems and flourish in the next century? This paper explores this question by examining threats to the future. Western culture, institutions and decision-making process are seen as anti-future and the strongest hazard to shaping a viable future for humanity. The paper offers an imaginative research programme to overcome this obstacle and discusses the inherent contradictions in the agenda. (C) 2000 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. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0016-3287 J9 FUTURES JI Futures PD FEB PY 2000 VL 32 IS 1 SI SI BP 17 EP 26 DI 10.1016/S0016-3287(99)00063-4 PG 10 WC Economics; Planning & Development SC Business & Economics; Public Administration GA 285ZK UT WOS:000085418100003 ER PT J AU Le Saux, O Urban, Z Goring, HHH Csiszar, K Pope, FM Richards, A Pasquali-Ronchetti, I Terry, S Bercovitch, L Lebwohl, MC Breuning, M van den Berg, P Kornet, L Doggett, N Ott, J de Jong, PTVM Bergen, AAB Boyd, CD AF Le Saux, O Urban, Z Goring, HHH Csiszar, K Pope, FM Richards, A Pasquali-Ronchetti, I Terry, S Bercovitch, L Lebwohl, MC Breuning, M van den Berg, P Kornet, L Doggett, N Ott, J de Jong, PTVM Bergen, AAB Boyd, CD TI Pseudoxanthoma elasticum maps to an 820-kb region of the p13.1 region of chromosome 16 (vol 62, pg 1, 1999) SO GENOMICS LA English DT Correction C1 Univ Hawaii Manoa, Pacific Biomed Res Ctr, Lab Matrix Pathobiol, Honolulu, HI 96822 USA. Columbia Univ, Dept Genet & Dev, New York, NY 10032 USA. Univ Wales Hosp, Inst Med Genet, MRC, Connect Tissue Genet Grp, Cardiff CF4 4XN, S Glam, Wales. Univ Cambridge, Dept Pathol, MRC, Connect Tissue Genet Grp, Cambridge CB2 1QP, England. Univ Modena, Dept Biomed Sci, I-41100 Modena, Italy. PXE Int Inc, Sharon, MA 02067 USA. Brown Univ, Dept Dermatol, Providence, RI 02908 USA. CUNY Mt Sinai Sch Med, Dept Dermatol, New York, NY 10029 USA. Leiden Univ, Dept Human Genet, NL-2333 AL Leiden, Netherlands. Univ Nijmegen St Radboud Hosp, Dept Neurol, NL-6500 MB Nijmegen, Netherlands. Univ Maastricht, Dept Med Physiol, NL-6200 MD Maastricht, Netherlands. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Rockefeller Univ, Lab Stat Genet, New York, NY 10021 USA. Netherlands Ophthalm Res Inst, NL-1100 AC Amsterdam, Netherlands. RP Le Saux, O (reprint author), Univ Hawaii Manoa, Pacific Biomed Res Ctr, Lab Matrix Pathobiol, Honolulu, HI 96822 USA. RI Urban, Zsolt/B-1977-2008; Breuning, Martijn/E-3429-2010; Urban, Zsolt/A-2018-2013; Bergen, Arthur/J-3637-2013 OI Urban, Zsolt/0000-0003-3890-1843; NR 1 TC 1 Z9 1 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 1 PY 2000 VL 63 IS 3 BP 439 EP 439 PG 1 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 292EH UT WOS:000085780800017 ER PT J AU Reneau, SL AF Reneau, SL TI Stream incision and terrace development in Frijoles Canyon, Bandelier National Monument, New Mexico, and the influence of lithology and climate SO GEOMORPHOLOGY LA English DT Article DE stream incision; stream terraces; lithologic control; climatic change; New Mexico ID SOUTHERN ROCKY-MOUNTAINS; ESPANOLA BASIN; COLORADO; YELLOWSTONE; VEGETATION; TIMBERLINE; ERUPTIONS; HISTORY; ARIZONA; EVENTS AB The record of stream incision and terrace development in Frijoles Canyon, NM, was investigated to examine the controls on channel evolution in this region. Frijoles Canyon developed after deposition of the voluminous ignimbrites of the Tshirege Member of the Bandelier Tuff at ca. 1.22 Ma, which provides excellent temporal constraints on canyon evolution. Base level fall along the Rio Grande, the master drainage in the region, contributed to initial incision of the stream. Development of a major knickpoint in basalt near the Rio Grande, however, has effectively isolated most of the stream channel from direct effects of this base level change since the Early or Middle Pleistocene. Late Quaternary evolution of the channel has included development of strath and fill terraces that record the effects of climatic Variations and local lithologic variations within the tuff on channel processes. A fill terrace, underlain by up to 13 m of coarse gravelly alluvium, records significant aggradation in the Early to Middle Holocene following a major regional climate change. Aggradation probably resulted from large increases in sediment supply in the Holocene relative to the Late Pleistocene, which was perhaps related to variations in intense summer rains. Rapid incision in the Middle to Late Holocene has stranded the underlying strath up to 21 m above the modern channel, and local rates of incision of up to 4 m/ka are more than 10 times the average rates since 1.22 Ma. Holocene incision displays great spatial variability associated with local lithologic variations, and results in a stream profile that has evolved rapidly in the last 10,000 years. The high rates of incision occur where easily eroded nonwelded tuff is exposed in the canyon bottom, whereas a more resistant vapor-phase altered tuff unit upstream has impeded incision. Incision may also have been affected by migration of knickpoints within the tuff. Paired strath terraces record periods of local base level stability and lateral erosion that were terminated by episodes of downcutting. The downcutting was probably controlled by rare high magnitude floods capable of stripping the pervasive gravel armor and exposing nonwelded tuff beneath the stream-bed. No tectonic influence an Late Quaternary terrace development or stream incision has been recognized despite Frijoles Canyon being crossed by the Pajarito fault zone, a major bounding structure of the Rio Grande Rift. Instead, climatic influences on sediment supply and flood characteristics, mediated by lithologic variations in the canyon bottom, have controlled Late Quaternary stream profile evolution. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Geol & Geochem Grp, Los Alamos, NM 87545 USA. RP Reneau, SL (reprint author), Univ Calif Los Alamos Natl Lab, Geol & Geochem Grp, MS D462, Los Alamos, NM 87545 USA. NR 73 TC 31 Z9 34 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD FEB PY 2000 VL 32 IS 1-2 BP 171 EP 193 DI 10.1016/S0169-555X(99)00094-X PG 23 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 297NA UT WOS:000086087900011 ER PT J AU Newman, GA Alumbaugh, DL AF Newman, GA Alumbaugh, DL TI Three-dimensional magnetotelluric inversion using non-linear conjugate gradients SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE 3-D magnetotelluric modelling; inversion; non-linear conjugate gradients; preconditioning ID 3-D ELECTROMAGNETIC-FIELDS; MARINE MAGNETOTELLURICS; PETROLEUM-EXPLORATION; EQUATIONS; RESPONSES; SYSTEM AB We have formulated a 3-D inverse solution for the magnetotelluric (MT) problem using the non-linear conjugate gradient method. Finite difference methods are used to compute predicted data efficiently and objective functional gradients. Only six forward modelling applications per frequency are typically required to produce the model update at each iteration. This efficiency is achieved by incorporating a simple line search procedure that calls for a sufficient reduction in the objective functional, instead of an exact determination of its minimum along a given descent direction. Additional efficiencies in the scheme are sought by incorporating preconditioning to accelerate solution convergence. Even with these efficiencies, the solution's realism and complexity are still limited by the speed and memory of serial processors. To overcome this barrier, the scheme has been implemented on a parallel computing platform where tens to thousands of processors operate on the problem simultaneously. The inversion scheme is tested by inverting data produced with a forward modelling code algorithmically different from that employed in the inversion algorithm. This check provides independent verification of the scheme since the two forward modelling algorithms are prone to different types of numerical error. C1 Sandia Natl Labs, Geophys Tech Dept, Albuquerque, NM 87185 USA. Univ Wisconsin, Dept Civil & Environm Engn, Madison, WI 53706 USA. RP Newman, GA (reprint author), Sandia Natl Labs, Geophys Tech Dept, POB 5800, Albuquerque, NM 87185 USA. EM ganewma@sandia.gov RI Newman, Gregory/G-2813-2015 NR 30 TC 149 Z9 184 U1 3 U2 31 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD FEB PY 2000 VL 140 IS 2 BP 410 EP 424 DI 10.1046/j.1365-246x.2000.00007.x PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 286RR UT WOS:000085459800012 ER PT J AU McAdams, KL Ergun, RE LaBelle, J AF McAdams, KL Ergun, RE LaBelle, J TI HF chirps: Eigenmode trapping in density depletions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WAVES AB Short-duration, narrow-bandwidth, HF chirps occur at slowly drifting frequencies above f(pe) when f(pe) > f(ce) [McAdams and LaBelle, 1999]. We put forth a model of the HF chirp emissions as quasi-trapped eigenmodes in a density depletion perpendicular to the ambient magnetic field. The escaping waves retain the frequency structure of the eigenmodes and are observed as HF chirps. We show that this model is quantitatively consistent with observed characteristics of HF chirps, most notably the frequency spacing of the chirp emissions (0.1-4 kHz), the fact that they are equally spaced independent of mode number, and the number of modes predicted for a given density cavity. Several mechanisms for the escape of the waves from the cavity are suggested. C1 Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP McAdams, KL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS D466, Los Alamos, NM 87545 USA. NR 8 TC 28 Z9 28 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 1 PY 2000 VL 27 IS 3 BP 321 EP 324 DI 10.1029/1999GL003655 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 282EY UT WOS:000085204900007 ER PT J AU Nicholl, MJ Rajaram, H Glass, RJ AF Nicholl, MJ Rajaram, H Glass, RJ TI Factors controlling satiated relative permeability in a partially-saturated horizontal fracture SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ROCK AB Recent work demonstrates that phase displacements within horizontal fractures large with respect to the spatial correlation length of the aperture field lead to a satiated condition that constrains the relative permeability to be less than one. We use effective media theory to develop a conceptual model for satiated relative permeability, then compare predictions to existing experimental measurements, and numerical solutions of the Reynolds equation on the measured aperture field within the flowing phase. The close agreement among all results and data show that for the experiments considered here, in-plane tortuosity induced by the entrapped phase is the dominant factor controlling satiated relative permeability. We also find that for this data set, each factor in the conceptual model displays an approximate power law dependence on the satiated saturation of the fracture. C1 Oklahoma State Univ, Sch Geol, Stillwater, OK 74078 USA. Univ Colorado, Dept Civil Environm & Architectural Engn, Boulder, CO 80309 USA. Sandia Natl Labs, Flow Visualizat & Proc Lab, Albuquerque, NM 87185 USA. RP Nicholl, MJ (reprint author), Oklahoma State Univ, Sch Geol, Stillwater, OK 74078 USA. NR 7 TC 25 Z9 25 U1 0 U2 2 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 FEB 1 PY 2000 VL 27 IS 3 BP 393 EP 396 DI 10.1029/1999GL006083 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 282EY UT WOS:000085204900025 ER PT J AU Geller, JT Kowalsky, MB Seifert, PK Nihei, KT AF Geller, JT Kowalsky, MB Seifert, PK Nihei, KT TI Acoustic detection of immiscible liquids in sand SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATTENUATION; VELOCITY; MEDIA AB Laboratory cross-well P-wave transmission at 90 kHz was measured in a 61 cm diameter by 76 cm tall water-saturated sand pack, before and after introducing a nonaqueous phase organic liquid (NAPL) (n-dodecane). In one experiment, NAPL was introduced to form a lens trapped by a low permeability layer; a second experiment considered NAPL residual trapped behind the front of flowing NAPL. The NAPL caused significant changes in the travel time and amplitude of first arrivals, as well as the generation of diffracted waves arriving after the direct wave. The spatial variations in NAPL saturation obtained from excavation at the end of the experiment correlated well with the observed variations in the P-wave amplitudes and travel times. NAPL residual saturation changes of 4% were detectable and the 40 to 80% NAPL saturation in the NAPL lens was clearly visible at acoustic frequencies. The results indicate that small NAPL saturations may be more easily detected with amplitude rather than travel time data, but that the relationships between the amplitude changes and NAPL saturation may be more complex than those for velocity. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. RP Geller, JT (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Nihei, Kurt/K-1239-2016 NR 9 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 1 PY 2000 VL 27 IS 3 BP 417 EP 420 DI 10.1029/1999GL010483 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 282EY UT WOS:000085204900031 ER PT J AU Berryman, JG AF Berryman, JG TI Seismic velocity decrement ratios for regions of partial melt in the lower mantle SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HIGH-PRESSURE; CORE; BASE; ATTENUATION; PERIDOTITE; ALUMINUM; BOUNDARY; LIQUID; PHASE AB For regions of partial melt in the lower mantle, both compressional and shear wave velocities decrease monotonically with increasing melt volume fraction. Those regions close to the core-mantle boundary thought to contain partial melt have a velocity decrement ratio (relative change in shear velocity over relative change of compressional velocity) of about 3. Arguments based on effective medium theories have been given to show that such high values of this ratio are predicted for partial melt systems. The present work confirms the value of 3 near the core-mantle boundary. It is shown, furthermore, that this velocity decrement ratio can be estimated without detailed knowledge of, or assumptions about, the microstructure of the partial melt system by using Gassmann's equation of poroelasticity together with some reasonable assumptions about the change (or lack of change) of the density and bulk modulus for lower mantle pressure and temperature conditions. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Berryman, JG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808 L-200, Livermore, CA 94551 USA. RI Berryman, James/A-9712-2008 NR 28 TC 41 Z9 41 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 1 PY 2000 VL 27 IS 3 BP 421 EP 424 DI 10.1029/1999GL008402 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 282EY UT WOS:000085204900032 ER PT J AU Oldenburg, CM Pruess, K AF Oldenburg, CM Pruess, K TI Simulation of propagating fronts in geothermal reservoirs with the implicit Leonard total variation diminishing scheme SO GEOTHERMICS LA English DT Article DE reservoir simulation; front propagation; numerical dispersion; higher-order schemes; total variation diminishing (TVD); Leonard scheme ID HYPERBOLIC CONSERVATION-LAWS; HIGH-RESOLUTION SCHEMES; FLUX; TRANSPORT AB Geothermal reservoir engineering requires accurate numerical solution of the advective-diffusive transport equations for strong advective flows of multiphase nonisothermal fluids. Conventional interface weighting schemes such as upstream weighting cause numerical dispersion. Numerical dispersion can be reduced by grid refinement, but this increases execution times and computer memory requirements. As an alternative, higher-order differencing schemes can be used to reduce numerical dispersion, but they often lead to spurious oscillations. These limitations have led to the development of higher-order schemes called total variation diminishing (TVD) schemes. For geothermal reservoir engineering, these schemes must be capable of handling flows that may not be physically total variation diminishing. We have implemented TVD schemes into the implicit geothermal reservoir simulator TOUGH2. We verify the Leonard TVD (LTVD) scheme by comparison to an analytical solution for two-dimensional flow and transport. The LTVD scheme reduces numerical dispersion for tracer transport in a two-phase geothermal reinjection problem. One-dimensional simulations show that the LTVD scheme works well even if the saturation variation increases with time. Because the location of the phase front is strongly coupled to temperature, phase front propagation is sensitive to grid resolution insofar as it affects the temperature field. Phase front propagation in a composite porous medium Buckley-Leverett flow problem, where phase saturations increase upon encountering a second medium, are slightly mole accurate for the LTVD scheme as compared to upstream weighting. We find that the LTVD scheme only performs well if the weighting and limiter are applied to saturation rather than to relative permeability. While there is some increased computational cost with the LTVD scheme due to increased linear equation solution time and smaller time-step size, the LTVD scheme is a practical and robust method for reducing numerical dispersion in complex flow problems relevant to geothermal reservoir engineering. (C) 2000 CNR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Oldenburg, CM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Oldenburg, Curtis/L-6219-2013 OI Oldenburg, Curtis/0000-0002-0132-6016 NR 26 TC 17 Z9 17 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0375-6505 J9 GEOTHERMICS JI Geothermics PD FEB PY 2000 VL 29 IS 1 BP 1 EP 25 DI 10.1016/S0375-6505(99)00048-6 PG 25 WC Energy & Fuels; Geosciences, Multidisciplinary SC Energy & Fuels; Geology GA 277ZT UT WOS:000084964000001 ER PT J AU Eckerman, KF Stabin, MG AF Eckerman, KF Stabin, MG TI Electron absorbed fractions and dose conversion factors for marrow and bone by skeletal regions SO HEALTH PHYSICS LA English DT Article DE dose, internal; modeling, dose assessment; bone marrow; skeleton ID RADIONUCLIDES; DOSIMETRY AB The possible inductions of bone cancer and leukemia are the two health effects of primary concern in the irradiation of the skeleton, The relevant target tissues to consider in the dosimetric evaluation have been the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia, The complex geometry of the soft tissue-bone intermixture makes calculations of absorbed doses to these target regions a difficult problem. In the case of photon or neutron radiations, charged particle equilibrium may not exist in the vicinity of a soft tissue-bone mineral interface. In this paper, absorbed fraction data are developed for calculations of the dose in the target tissues from electron emitters deposited within the volume or on the surfaces of trabecular bone, The skeletal average absorbed fractions presented are consistent with usage of this quantity in the contemporary dosimetric formulations of the International Commission on Radiological Protection (ICRP), Implementation of the new bone and marrow model is then developed within the context of the calculational schema of the Medical Internal Radiation Dose (MIRD) Committee. Model parameters relevant to the calculation of dose conversion factors (S values) for different regions of the skeleton of individuals of various age are described, and an example calculation is performed for a monoclonal antibody which localizes in the marrow. The utility of these calculations for radiation dose calculations in nuclear medicine is discussed. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Univ Fed Pernambuco, BR-50740240 Recife, PE, Brazil. EM kfe@ornl.gov NR 34 TC 81 Z9 84 U1 0 U2 3 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 FEB PY 2000 VL 78 IS 2 BP 199 EP 214 DI 10.1097/00004032-200002000-00009 PG 16 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 275WK UT WOS:000084843000008 PM 10647986 ER PT J AU Kaurin, DGL Carsten, AL Baum, JW AF Kaurin, DGL Carsten, AL Baum, JW TI Effective half-lives for patients administered radiolabeled antibodies and calculated dose to the public in close proximity to patients SO HEALTH PHYSICS LA English DT Article DE exposure, population; medical radiation; radiopharmaceuticals; effective dose ID MONOCLONAL-ANTIBODY AB Effective half-lives (T-e) for radiolabeled antibodies can be much longer than that of traditional radiopharmaceuticals, potentially resulting in larger doses to members of the public. Clearance-rate data from patients treated with radiolabeled antibodies (RABs) were obtained from ten institutions. Calculations were made to determine if a single- or biexponential clearance-rate model was statistically justified; the results indicated that the former model was justified for more than 95% of the data. Values of T-e for the different RABs are summarized. To plan actions to limit doses to less than 5 mSv annually for individuals continuously close to the patient (at 1 m), dose rates from patients at the time of release also are given as a function of T-e. C1 Brookhaven Natl Lab, Dept Adv Technol, Radiol Sci Div, Upton, NY 11973 USA. EM darryl.kaurin@mcmail.vanderbilt.edu NR 13 TC 3 Z9 3 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 FEB PY 2000 VL 78 IS 2 BP 215 EP 221 DI 10.1097/00004032-200002000-00010 PG 7 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 275WK UT WOS:000084843000009 PM 10647987 ER PT J AU Reif, RH Houck, RS AF Reif, RH Houck, RS TI Poor design of local exhaust hood leads to radioactive release in the work area SO HEALTH PHYSICS LA English DT Article DE exposure, occupational; ventilation; plutonium; waste management AB At a U.S. Department of Energy (DOE) waste handling facility, transuranic waste contained in standard 208-L (55-gallon)drums was being prepared to meet the DOE's Waste Isolation Pilot Project Waste Acceptance Criteria. During a particular waste handling: operation, it was necessary for the workers to open several 208-L drums with TRU waste and prepare the waste to meet the WIPP Waste Acceptance Criteria. This operation was performed while the waste drums where positioned adjacent to a drum ventilator, which was designed to capture emissions generated from the drums during waste handling activities, During this activity, the continuous air monitor alarmed and reached an instantaneous air concentration of 0.1 Bq m(-3), or a factor of 300 times higher than the derived air concentration fur inhalation class W Pu-239. The DOE conducted an investigation to determine why the drum ventilator did not control the transuranic emissions and to evaluate possible improvements to the drum ventilator and exposure controls. By adding upper and lower flanges to the drum ventilator, the capture velocity was increased by 88% without increasing the fan's speed. Adding flanges is a simple and inexpensive modification that enhances the performance of the drum ventilator. In addition to a poor design, the drum ventilator's capture velocity was compromised by competing air velocities that were generated by waste handling activities. C1 US DOE, Brookhaven Grp, Upton, NY 11973 USA. US DOE, Kirkland Area Off, Albuquerque, NM 87185 USA. EM rreif@bnl.gov NR 3 TC 0 Z9 0 U1 0 U2 1 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 FEB PY 2000 VL 78 IS 2 BP 222 EP 225 DI 10.1097/00004032-200002000-00011 PG 4 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 275WK UT WOS:000084843000010 PM 10647988 ER PT J AU Eifert, EJ Vickers, LD AF Eifert, EJ Vickers, LD TI The dissolution vessel for plutonium pits at the US DOE Pantex Plant SO HEALTH PHYSICS LA English DT Article DE operational topics; plutonium; occupational safety; weapons AB The U.S. DOE Pantex Plant has been given the mission to recertify and requalify plutonium pits for reuse in existing War Reserve nuclear weapons. The first process common to both recertification and requalification is cleaning the plutonium pit The pit will be cleaned in a dissolution vessel using N-methyl pyrrolidone (NMP) solvent, The recertification and requalification programs are both in the design concept phase at Pantex Plant. The U.S. DOE Pantex Plant secures the national security of the United States by using safe vessels for cleaning plutonium pits in a manner that protects the health and safety of employees, the public and the environment. C1 US DOE Pantex Plant, Amarillo, TX 79120 USA. NR 3 TC 0 Z9 0 U1 0 U2 2 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 FEB PY 2000 VL 78 IS 2 SU S BP S25 EP S27 DI 10.1097/00004032-200002001-00008 PG 3 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 278HX UT WOS:000084984200008 PM 10651401 ER PT J AU Miller, M Galloway, B VanDerpoel, G Johnson, E Copland, J Salazar, M AF Miller, M Galloway, B VanDerpoel, G Johnson, E Copland, J Salazar, M TI An alternative for cost-effective remediation of depleted uranium (DU) at certain environmental restoration sites SO HEALTH PHYSICS LA English DT Article DE operational topics; uranium; contamination; radiation protection AB Numerous sites in the United States and around the world are contaminated with depleted uranium (DU) in various forms. A prevalent form is fragmented DU originating from various scientific tests involving high explosives and DU during weapon development programs, at firing practice ranges, dr war theaters where DU was used in armor-piercing projectiles. The contamination at these sites is typically very heterogeneous, with discreet, visually identifiable DU fragments mixed with native soil. That is, the bulk-averaged DU activity is quite low, while specific DU fragments, which are distinct from the soil matrix, have much higher specific activity. DU is best known as a dark, black metal that is nearly twice as dense as lead, but DU in the environment readily weathers (oxidizes) to a distinctive bright yellow color that is readily visible. While the specific activity (amount of radioactivity per mass of soil) of DU is relatively low and presents only a minor radiological hazard, the fact that it is radioactive and visually identifiable makes it desirable to remove the DU "contamination" from the environment. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Sci Applicat Int Corp, Mclean, VA 22102 USA. NR 6 TC 4 Z9 4 U1 3 U2 5 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 FEB PY 2000 VL 78 IS 2 SU S BP S9 EP S12 DI 10.1097/00004032-200002001-00004 PG 4 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 278HX UT WOS:000084984200004 PM 10651397 ER PT J AU Kelly, EJ Campbell, K AF Kelly, EJ Campbell, K TI Separating variability and uncertainty in environmental risk assessment - Making choices SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE variability; uncertainty; risk; minimum variance unbiased estimation; Bayesian Estimation; two-stage Monte Carlo AB This article reviews some of the current guidance concerning the separation of variability and uncertainty in presenting the results of human health and ecological risk assessments. Such guidance and some of the published examples of its implementation using two-stage Monte Carlo simulation methods have not emphasized the fact that there is considerable judgment involved in determining which input parameters can be modeled as purely variable or purely uncertain, and which require explicit treatment in both dimensions. Failure to discuss these choices leads to confusion and misunderstanding of the proposed methods. We conclude with an example illustrating some of the reasoning and statistical calculations that might be used to inform such choices. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Kelly, EJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 15 TC 34 Z9 37 U1 1 U2 5 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 FEB PY 2000 VL 6 IS 1 BP 1 EP 13 DI 10.1080/10807030091124419 PG 13 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 298MQ UT WOS:000086143800001 ER PT J AU Adams, SM Greeley, MS Ryon, MG AF Adams, SM Greeley, MS Ryon, MG TI Evaluating effects of contaminants on fish health at multiple levels of biological organization: Extrapolating from lower to higher levels SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE bioindicators; biomarkers; gradient responses; ecological risk assessment; environmental stress ID RISK ASSESSMENT; BIOMARKERS; POPULATIONS; RESPONSES; COMMUNITY AB Effects of environmental stressors such as contaminants on the health of aquatic ecosystems usually involve a series of biological responses ranging from the biomolecular/biochemical to the population and community levels. To establish relationships and to determine the feasibility of extrapolating between higher and lower levels of biological organization, spatial patterns in fish responses to contaminant loading were investigated in a stream receiving point-source discharges of various contaminants near its headwaters. Relationships among fish responses at four major levels of biological organization (biochemical/physiological, individual, population, and community levels) were evaluated relative to patterns in contaminant loading along the spatial gradient of the stream. Both individual and integrated response analysis demonstrated that bioindicators at several levels of biological organization displayed similar downstream patterns in their response to contaminant loading within the stream. Some of the bioindicator responses at lower levels of organization appear to be useful for the ecological risk assessment process because of their sensitivity and apparent relationships to higher levels. By identifying and establishing relationships between levels of biological organization we should be better able to understand the mechanisms of stress responses in ecological systems that could ultimately result in improved predictive capability of ecological risk assessment and also allow for more informed decisions regarding remedial actions. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Adams, SM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Greeley, Mark/D-2330-2016 OI Greeley, Mark/0000-0002-6088-5942 NR 30 TC 38 Z9 40 U1 2 U2 18 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 FEB PY 2000 VL 6 IS 1 BP 15 EP 27 DI 10.1080/10807030091124428 PG 13 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 298MQ UT WOS:000086143800002 ER PT J AU Murphy, EM Ginn, TR AF Murphy, EM Ginn, TR TI Modeling microbial processes in porous media SO HYDROGEOLOGY JOURNAL LA English DT Review DE contamination; bacterial transport; numerical modeling; microbial processes ID BIOLOGICALLY REACTING SOLUTES; OXIDIZING MIXED CULTURE; SANDY AQUIFER; BACTERIAL TRANSPORT; IN-SITU; COMPETITIVE-INHIBITION; PHYSICAL HETEROGENEITY; CONTAMINANT TRANSPORT; MATHEMATICAL-MODELS; ESCHERICHIA-COLI AB The incorporation of microbial processes into reactive transport models has generally proceeded along two separate lines of investigation: (1) transport of bacteria as inert colloids in porous media, and (2) the biodegradation of dissolved contaminants by a stationary phase of bacteria. Research over the last decade has indicated that these processes are closely linked. This linkage may occur when a change in metabolic activity alters the attachment/detachment rates of bacteria to surfaces, either promoting or retarding bacterial transport in a groundwater-contaminant plume. Changes in metabolic activity, in turn, are controlled by the time of exposure of the microbes to electron acceptors/donor and other components affecting activity. Similarly, metabolic activity can affect the reversibility of attachment, depending on the residence time of active microbes. Thus, improvements in quantitative analysis of active subsurface biota necessitate direct linkages between substrate availability, metabolic activity, growth, and attachment/detachment rates. This linkage requires both a detailed understanding of the biological processes and robust quantitative representations of these processes that can be rested experimentally. This paper presents an overview of current approaches used to represent physicochemical and biological processes in porous media, along with new conceptual approaches that link metabolic activity with partitioning of the microorganism between the aqueous and solid phases. C1 Pacific NW Lab, Interfacial Geochem Grp, Richland, WA 99352 USA. Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA. RP Murphy, EM (reprint author), Pacific NW Lab, Interfacial Geochem Grp, MSIN K3-61,POB 999, Richland, WA 99352 USA. NR 138 TC 120 Z9 123 U1 2 U2 46 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1431-2174 J9 HYDROGEOL J JI Hydrogeol. J. PD FEB PY 2000 VL 8 IS 1 BP 142 EP 158 DI 10.1007/s100409900043 PG 17 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 300RZ UT WOS:000086267100013 ER PT J AU Keller, PE McMakin, DL Sheen, DM McKinnon, AD Summet, JW AF Keller, PE McMakin, DL Sheen, DM McKinnon, AD Summet, JW TI Privacy algorithm for cylindrical holographic weapons surveillance system SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB A novel personnel surveillance system has been developed to detect and identify threatening objects, which are undetectable by metal detectors, concealed on the human body. This new system can detect threats which are fabricated with plastic, liquid, metal, or ceramic. It uses millimeter-wave array technology and a cylindrical holographic imaging algorithm to provide full-body, 360-degree coverage of a person in near real-time. This system is ideally suited for mass transportation centers such as airport checkpoints that require high throughput rates and full coverage. Research and development efforts are underway to produce a privacy algorithm that removes the human features from the images while identifying the potential threats. This algorithm locates and segments the threats and places them on a wire-frame humanoid representation. The research areas for this algorithm development include artificial neural networks, image processing, edge detection, and dielectric measurements. This system is operational and results from this test and the privacy algorithm will be discussed in this paper. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Keller, PE (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 6 TC 10 Z9 11 U1 1 U2 6 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 FEB PY 2000 VL 15 IS 2 BP 17 EP 23 DI 10.1109/62.825667 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 291YX UT WOS:000085768300004 ER PT J AU Xiong, Y Zhou, Y Zhu, ZH Lo, YH Ji, C Bashar, SA Allerman, AA Hargett, T Sieg, R Choquette, KD AF Xiong, Y Zhou, Y Zhu, ZH Lo, YH Ji, C Bashar, SA Allerman, AA Hargett, T Sieg, R Choquette, KD TI Oxide-defined GaAs vertical-cavity surface-emitting lasers on Si substrates SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE semiconductor device fabrication; semiconductor lasers; vertical-cavity surface-emitting lasers (VCSEL's); wafer bonding ID MIRRORS AB By employing a reactive low-temperature wafer bonding technique, we have demonstrated oxide-defined 850 nm vertical-cavity surface-emitting lasers (VCSEL's) on Si substrates. Devices reach a differential quantum efficiency of 53% and a light output power of 7.1 mW under room temperature and continuous-wave operation without a heat sink. C1 Cornell Univ, Ithaca, NY 14853 USA. Nova Crystals Inc, Ithaca, NY 14850 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Xiong, Y (reprint author), Cornell Univ, Ithaca, NY 14853 USA. NR 9 TC 5 Z9 6 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 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD FEB PY 2000 VL 12 IS 2 BP 110 EP 112 DI 10.1109/68.823486 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 285XW UT WOS:000085414500004 ER PT J AU Yang, K Hains, CP Cheng, JL Allerman, AA AF Yang, K Hains, CP Cheng, JL Allerman, AA TI Efficient double intracavity-contacted vertical-cavity surface-emitting lasers with very low-threshold and low-power dissipation designed for cryogenic applications SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE low-temperature performance; MOCVD; quantum-well laser; semiconductor lasers; surface-emitting laser ID OPERATION AB Efficient continuous wave operation of oxide-confined double intracavity-contacted InGaAs-GaAs vertical-cavity surface-emitting lasers (VCSEL's) with low-threshold voltage, low-threshold current and low-power dissipation has been achieved over a wide range of cryogenic temperatures (77 K-250 K), Low operating voltages were obtained by routing current through two intracavity contacts to bypass both distributed Bragg reflector (DBR) mirrors, while lower optical losses were achieved by using undoped DBR mirrors with abrupt heterointerfaces. This resulted in low operating voltages (<1.5 V), submilliampere threshold currents (I-th similar to 0.15 mA), low-power dissipation (similar to 0.21 mW at threshold) and a high power conversion efficiency (eta(eff) = 31%). C1 Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Yang, K (reprint author), Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. NR 8 TC 3 Z9 3 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 FEB PY 2000 VL 12 IS 2 BP 113 EP 115 DI 10.1109/68.823487 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 285XW UT WOS:000085414500005 ER PT J AU Zhou, YX Cheng, J Allerman, AA AF Zhou, YX Cheng, J Allerman, AA TI High-speed wavelength-division multiplexing and demultiplexing using monolithic quasi-planar VCSEL and resonant photodetector arrays with strained InGaAs quantum wells SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE monolithic VCSEL arrays; multiwavelength sources; optical interconnects; resonant photodetectors; wavelength-division multiplexing AB We demonstrate the high-speed (gigabit-per-second) operation of a wavelength-division-multiplexed optical interconnect, which is implemented by multiplexing the optical data from a multiple-wavelength vertical-cavity surface-emitting laser (VCSEL) array into a single optical fiber, and demultiplexing the composite data stream using an array of resonance-enhanced photodetectors (REPD's) with matching resonance wavelengths. By using VCSEL's and REPD's with a new quasi-planar oxide-confinement design for improved high-speed performance, and using strained InGaAs-GaAs quantum wells to achieve a better tradeoff between optical responsivity and wavelength selectivity, wavelength-division-multiplexing (WDM) operation has been demonstrated under 1-Gb/s data modulation, with an optical crosstalk rejection ratio of better than -10 dB for wavelength channels that are spaced 4 nm apart. C1 Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Zhou, YX (reprint author), Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87106 USA. NR 5 TC 29 Z9 30 U1 1 U2 4 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 FEB PY 2000 VL 12 IS 2 BP 122 EP 124 DI 10.1109/68.823490 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 285XW UT WOS:000085414500008 ER PT J AU Chang, JT Fanning, MW Meaney, PM Paulsen, KD AF Chang, JT Fanning, MW Meaney, PM Paulsen, KD TI A conductive plastic for simulating biological tissue at microwave frequencies SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE dielectric materials; imaging; microwave; phantom; tissue equivalent ID HYPERTHERMIA APPLICATORS; PHANTOM MATERIAL; POLYMER BLENDS; CARBON-BLACK; POLYACRYLAMIDE; SYSTEM AB A conductive plastic composite that exhibits complex dielectric properties similar to biological tissues over the electromagnetic spectrum of 300-900 MHz has been synthesized from compressed carbon black mixed with a castable thermoplastic. This paper presents the techniques used to control the electrical properties of the conductive plastic and describes the challenges encountered in fabricating a material containing a high proportion of carbon black. While developed to serve as a housing material for a microwave antenna array for imaging biological bodies, the composite should be useful in any setting requiring a stable, solid, high-loss material that simulates biological tissues over the microwave spectrum. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. Dartmouth Hitchcock Med Ctr, Norris Cotton Canc Ctr, Lebanon, NH 03766 USA. RP Chang, JT (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 27 TC 14 Z9 14 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD FEB PY 2000 VL 42 IS 1 BP 76 EP 81 DI 10.1109/15.831707 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 302PZ UT WOS:000086375500009 ER PT J AU Kwan, TJT AF Kwan, TJT TI On the delay time for the onset of radiographic spot size growth SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 1st First International Symposium on Nonthermal Medical/Biological Treatments Using Electromagnetic Fields and Ionizes Gases (ElectroMed99) CY APR 12-14, 1999 CL NORFOLK, VIRGINIA SP USAF Off Sci Res, Natl Sci Fdn, IEEE Nucl & Plasma Sci Soc, Bioelectromagnet Soc, Old Dominion Univ, Eastern Virgina Med Sch, Coll William & Mary DE beam-target interaction; electron beam spot; ion neutralization; radiography AB We have revisited the physical mechanisms, which lead to a time delay of the onset of the undesirable spot size growth in high-dose X-ray radiography, In our theoretical model, the delay time is partially due to the time needed for the electron beam to thermally ionize the target spot resulting in target ions and partially due to the time needed for the ions to form a column of at least a quarter of the betatron wavelength of the electron beam, Based on our model, an analytic formula is derived, and it has been found to be consistent with experimental observations for different target materials and beam parameters, Our analysis shows that the delay time is directly proportional to the beam spot size at the target and inversely proportional to the beam current. Our calculations further show the spot size of the DARHT-1 beam with 2 kA current should be stable because the delay time of about 69 ns is longer than the beam pulse length. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Plasma Phys Applicat Grp, Los Alamos, NM 87544 USA. RP Kwan, TJT (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Plasma Phys Applicat Grp, POB 1663, Los Alamos, NM 87544 USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 2000 VL 28 IS 1 BP 268 EP 270 DI 10.1109/27.842920 PG 3 WC Physics, Fluids & Plasmas SC Physics GA 314XE UT WOS:000087082200039 ER PT J AU Starkweather, BA Zhang, XG Counce, RM AF Starkweather, BA Zhang, XG Counce, RM TI An experimental study of the change in the contact angle of an oil on a solid surface SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID DODECYL-SULFATE; ADSORBED LAYER; ADSORPTION; INTERFACE; TENSION; COUNTERIONS; MODEL AB The effects of pH and surfactant concentration on the change in the contact angle of an oil on both stainless steel and glass surfaces have been studied. The pH ranged from 7.0 to 10.0. Sodium dodecyl sulfate (SDS), an anionic surfactant, was the surfactant used in this study. Two different surfactant concentrations were used, one concentration near the critical micelle concentration (cmc) and one concentration significantly above the cmc. The interfacial tension between the oil and surfactant solutions was measured over the same pH and concentration ranges as the contact angle measurements. Increasing the pH as well as increasing the surfactant concentration causes a decrease in the oil/surfactant solution interfacial tension for solutions of SDS. Over the range of pH values and SDS concentrations studied, increasing the pH and surfactant concentration above the cmc hinders the change in the contact angle of the oil on both the stainless steel and glass surfaces despite the decrease in the interfacial tension. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37919 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Counce, RM (reprint author), Univ Tennessee, Dept Chem Engn, Knoxville, TN 37919 USA. NR 27 TC 25 Z9 26 U1 3 U2 11 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 FEB PY 2000 VL 39 IS 2 BP 362 EP 366 DI 10.1021/ie980693g PG 5 WC Engineering, Chemical SC Engineering GA 283YF UT WOS:000085303100016 ER PT J AU Weber, CF Beahm, EC Lee, DD Watson, JS AF Weber, CF Beahm, EC Lee, DD Watson, JS TI A solubility model for aqueous solutions containing sodium, fluoride, and phosphate ions SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID SOLGASMIX AB A computational model is developed to calculate thermodynamic phase equilibria in aqueous solutions of fluoride, phosphate, and hydroxide up to 100 degrees C. A variety of data are used, including isopiestic and electromotive force measurements, freezing point data, vapor pressure data at 100 degrees C, heat capacities, heats of dilution, and solubility measurements. Fitter's ion-interaction treatment is used to model electrolyte solutions, and many unknown parameters are determined from existing data through nonlinear least-squares fitting. Phase equilibria are determined by minimization of the total Gibbs energy using a modification of the code SOLGASMIX. Results calculated using the model accurately predict phase equilibria from many quantitative experiments. Qualitative experiments are performed to evaluate calculated solubilities in regions of sparse or nonexistent data; the calculated results are reasonable and exhibit a general qualitative agreement with such data. Model predictions are useful in understanding problems that may arise in the treatment of waste streams containing fluoride and phosphate anions in highly caustic solutions. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Weber, CF (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 25 TC 13 Z9 14 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD FEB PY 2000 VL 39 IS 2 BP 518 EP 526 DI 10.1021/ie990457l PG 9 WC Engineering, Chemical SC Engineering GA 283YF UT WOS:000085303100034 ER PT J AU Ju, YH Webb, OF Dai, S Lin, JS Barnes, CE AF Ju, YH Webb, OF Dai, S Lin, JS Barnes, CE TI Synthesis and characterization of ordered mesoporous anion-exchange inorganic/organic hybrid resins for radionuclide separation SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID FUNCTIONALIZED MONOLAYERS; MOLECULAR-SIEVES; PORE STRUCTURE; SILICA AB Ordered mesoporous anion-exchange hybrid resin materials were prepared by hydrolysis synthesis using the micellar template approach. The prepared samples were characterized via infrared spectroscopy, nitrogen sorption, and small-angle X-ray scattering. The uptakes of anionic thorium nitrate complexes by the new resins in 8 N nitric acid solutions were determined. The thorium loading capacity of the hybrid mesoporous silica functionalized with N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium is greater than that of the hybrid mesoporous silica functionalized with N-trimethoxylsilylpropyl-N,N,N-trimethylammonium The mesoporous hybrid anion-exchange resins were shown to be much more selective than a popular organic commercial anion-exchange resin. C1 Oak Ridge Natl Lab, Chem Technol Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Solid Sate Div, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RP Dai, S (reprint author), Oak Ridge Natl Lab, Chem Technol Div, POB 2008, Oak Ridge, TN 37831 USA. RI Dai, Sheng/K-8411-2015 OI Dai, Sheng/0000-0002-8046-3931 NR 27 TC 58 Z9 64 U1 0 U2 11 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 FEB PY 2000 VL 39 IS 2 BP 550 EP 553 DI 10.1021/ie990597v PG 4 WC Engineering, Chemical SC Engineering GA 283YF UT WOS:000085303100039 ER PT J AU Huebsch, JJ Kramer, MJ Zhao, HL Akinc, M AF Huebsch, JJ Kramer, MJ Zhao, HL Akinc, M TI Solubility of boron in Mo(5+y)Si(3-y) SO INTERMETALLICS LA English DT Article DE silicides AB Using X-ray analysis, optical microscopy, chemical analysis, and electron probe microanalysis (EPMA) it has been determined that the level of boron solubility in Mo(5+y)Si(3-y) at 1800 degrees C reaches a maximum value of approximately 2 at% in a narrow region within the homogeneity range of -0.08 less than or equal to y less than or equal to 0.04. Both the B doped and undoped Mo(5+y)Si(3-y) (T1) have the tetragonal W(5)Si(3) crystal structure, which corresponds to the I4/mcm space group. Within the single phase Mo(5+y)Si(3-y)B(x) (T1) region then is a contraction in the lattice Volume with increasing boron concentration while there is an increase in cell volume with an increase in Mo:Si ratio. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Kramer, MJ (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 11 TC 31 Z9 37 U1 1 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD FEB PY 2000 VL 8 IS 2 BP 143 EP 150 DI 10.1016/S0966-9795(99)00082-5 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 274GA UT WOS:000084754500007 ER PT J AU Miura, S Terada, Y Suzuki, T Liu, CT Mishima, Y AF Miura, S Terada, Y Suzuki, T Liu, CT Mishima, Y TI Thermal conductivity of Ni-Al powder compacts for reaction synthesis SO INTERMETALLICS LA English DT Article DE nickel-aluminides, based on TiAl; thermal properties; reaction synthesis; powder metallurgy ID COMBUSTION SYNTHESIS; FULL DENSITY AB Thermal conductivity of 3Ni-1Al elemental powder compacts was measured using a laser-flash method as a function of temperature, compact density and heat treatment. Temperature dependence of thermal conductivity of the compacts is similar to that of pure Ni and Al metals. Heat treatment has a significant effect on the thermal conductivity of the compacts as particles are joined together to form Ni solid solution and intermetallic phases on powder surfaces. Fast diffusion on powder surfaces during heat treatment results in the formation of intermetallic phase zones in the interior of the former Ni particles. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Hokkaido Univ, Div Mat Sci & Engn, Grad Sch Engn, Kita Ku, Sapporo, Hokkaido 0608628, Japan. Tokyo Inst Technol, Dept Met & Ceram Sci, Meguro Ku, Tokyo 1528552, Japan. Kochi Univ Technol, Kochi 7828520, Japan. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Tokyo Inst Technol, Interdisciplinary Grad Sch Sci & Engn, Midori Ku, Yokohama, Kanagawa 2268502, Japan. RP Miura, S (reprint author), Hokkaido Univ, Div Mat Sci & Engn, Grad Sch Engn, Kita Ku, Kita 13,Nishi 8, Sapporo, Hokkaido 0608628, Japan. RI Miura, Seiji/A-6431-2012; OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 18 TC 17 Z9 17 U1 2 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD FEB PY 2000 VL 8 IS 2 BP 151 EP 155 DI 10.1016/S0966-9795(99)00080-1 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 274GA UT WOS:000084754500008 ER PT J AU Fedoseyev, AI Friedman, MJ Kansa, EJ AF Fedoseyev, AI Friedman, MJ Kansa, EJ TI Continuation for nonlinear elliptic partial differential equations discretized by the multiquadric method SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article ID COMPUTATIONAL FLUID-DYNAMICS; DATA APPROXIMATION SCHEME; SCATTERED DATA; INTERPOLATION; BIFURCATION AB The Multiquadric Radial Basis Function (MQ) Method is a meshless collocation method with global basis functions. It is known to have exponentional convergence for interpolation problems. We descretize nonlinear elliptic PDEs by the MQ method. This results in modest-size systems of nonlinear algebraic equations which can be efficiently continued by standard continuation software such as AUTO and CONTENT. Examples are given of detection of bifurcations in 1D and 2D PDEs. These examples show high accuracy with small number of unknowns, as compared with known results from the literature. C1 Univ Alabama, Ctr Micrograv & Mat Res, Huntsville, AL 35899 USA. Univ Alabama, Dept Math Sci, Huntsville, AL 35899 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Fedoseyev, AI (reprint author), Univ Alabama, Ctr Micrograv & Mat Res, Huntsville, AL 35899 USA. NR 48 TC 37 Z9 37 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-1274 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD FEB PY 2000 VL 10 IS 2 BP 481 EP 492 DI 10.1142/S0218127400000323 PG 12 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA 305ZE UT WOS:000086571000015 ER PT J AU Khraishi, TA Hirth, JP Zbib, HM Khaleel, MA AF Khraishi, TA Hirth, JP Zbib, HM Khaleel, MA TI The displacement, and strain-stress fields of a general circular Volterra dislocation loop SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article DE dislocation; elasticity AB A closed-form analytical solution for the displacement, and strain-stress fields of a circular Volterra dislocation loop having a glide and prismatic components is obtained. Assuming linear elasticity and infinite isotropic material, the displacement field is found by integrating the Burgers displacement equation for a circular dislocation loop. The strain field is subsequently obtained and stresses follow from Hooke's law. The field equations are expressed in terms of complete elliptic integrals of the first, second, and/or third elliptic integrals. The general loop solution is, from the principle of superposition, the additive sum of the prismatic and glide solutions. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Zbib, HM (reprint author), Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. NR 20 TC 22 Z9 22 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD FEB PY 2000 VL 38 IS 3 BP 251 EP 266 DI 10.1016/S0020-7225(99)00038-5 PG 16 WC Engineering, Multidisciplinary SC Engineering GA 278EL UT WOS:000084974900001 ER PT J AU Drumheller, DS AF Drumheller, DS TI On theories for reacting immiscible mixtures SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article AB On some small scale each constituent of an immiscible mixture occupies a separate region of space. Given sufficient time and computing power: we could solve the continuum field equations and boundary conditions for this heterogeneous system. This usually represents an enormously difficult task that is well beyond today's computational capabilities. Mixture theories approximate this complex heterogeneous formulation with a set of field equations for an equivalent homogeneous material. In this work, we compare the theory for immiscible mixtures by Drumheller and Bedford with the theory of Passman, Nunziato, and Walsh. We describe the conditions under which these theories reduce to an equivalent formulation, and we also investigate the differences in their microinertial descriptions. Two variables play special roles in both theories. They are the true material density and the volume fraction. Here we use a kinematical approach based on two new variables - the true deformation gradient and the distention gradient. We show how the true deformation gradient is connected to the true material density and, in the absence of chemical reactions, the volume fraction is the inverse of the determinant of the distention gradient. However, when chemical reactions occur: the distention gradient and the volume fraction are not directly connected. We also present a mixture model for a granular explosive. This model is based upon the work of Baer and Nunziato, but our theory differs from their work in that we present a three-dimensional model, we cast the constitutive postulates in terms of the distention gradient rather than the volume fraction, and we incorporate elastic-plastic effects into the constitutive description of the solid granules. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Sandia Corp, Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Drumheller, DS (reprint author), Sandia Corp, Sandia Natl Labs, Mail Stop 1033,POB 5800, Albuquerque, NM 87185 USA. NR 19 TC 18 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD FEB PY 2000 VL 38 IS 3 BP 347 EP 382 DI 10.1016/S0020-7225(99)00047-6 PG 36 WC Engineering, Multidisciplinary SC Engineering GA 278EL UT WOS:000084974900008 ER PT J AU Wen, WW AF Wen, WW TI An integrated fine coal preparation technology: the GranuFlow Process SO INTERNATIONAL JOURNAL OF MINERAL PROCESSING LA English DT Article DE dewatering; bitumen; emulsion; microagglomerate; centrifuge; fine coal; moisture reduction; dust reduction; GranuFlow Process AB In order to alleviate the problems of fine coal handling and processing and to enhance the utilization of fines by utilities, US Department of Energy's (DOE's) Federal Energy Technology Center (FETC) developed and patented the GranuFlow Process. This paper summarizes recent test results of the GranuFlow Process with pilot-scale and plant-scale centrifuges in commercial plants. The main benefits of the GranuFlow Process are that it can potentially reduce the amount of waste coal that is stored in refuse impoundments, reduce the moisture content of the final clean coal product, improve handling by converting wet sticky fines to a granular, free-flowing material, prevent frozen coal problems in rail cars, and reduce the dustiness and fugitive dust losses during transportation and handling. Since Orimulsion is a low cost bitumen emulsion, this technology provides the coal industry with a cost-effective technology for fine coal processing. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 US Dept Energy, Natl Energy Technol Lab, Pittsburgh, PA 15236 USA. RP Wen, WW (reprint author), US Dept Energy, Natl Energy Technol Lab, POB 10940, Pittsburgh, PA 15236 USA. NR 15 TC 4 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-7516 J9 INT J MINER PROCESS JI Int. J. Miner. Process. PD FEB PY 2000 VL 58 IS 1-4 BP 253 EP 265 DI 10.1016/S0301-7516(99)00073-3 PG 13 WC Engineering, Chemical; Mineralogy; Mining & Mineral Processing SC Engineering; Mineralogy; Mining & Mineral Processing GA 299VK UT WOS:000086218400020 ER PT J AU Paunesku, T Chang-Liu, CM Shearin-Jones, P Watson, C Milton, J Oryhon, J Salbego, D Milosavljevic, A Woloschak, GE AF Paunesku, T Chang-Liu, CM Shearin-Jones, P Watson, C Milton, J Oryhon, J Salbego, D Milosavljevic, A Woloschak, GE TI Identification of genes regulated by UV/salicylic acid SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID NF-KAPPA-B; EUKARYOTIC INITIATION FACTOR-4B; IMMUNODEFICIENCY-VIRUS TYPE-1; RNA RECOGNITION MOTIF; SODIUM-SALICYLATE; TRANSCRIPTION FACTOR; ONCOPROTEIN BCL-3; CCAAT BINDING; PHORBOL ESTER; GROWTH-FACTOR AB Purpose: Previous work from the authors' group and others has demonstrated that some of the effects of UV irradiation on gene expression are modulated in response to the addition of salicylic acid to irradiated cells. The presumed effector molecule responsible for this modulation is NF-KB. In the experiments described here, differential-display RT-PCR was used to identify those cDNAs that are differentially modulated by UV radiation with and without the addition of salicylic acid. Materials and methods: Differential-display RT-PCR was used to identify differentially expressed genes. Results: Eight such cDNAs are presented: lactate dehydrogenase (LDH-beta), nuclear encoded mitochondrial NADH ubiquinone reductase 24kDa (NDUFV2), elongation initiation factor 4B (eIF4B), nuclear dots protein SP100, nuclear encoded mitochondrial ATPase inhibitor (IF1), a cDNA similar to a subunit of yeast CCAAT transcription factor HAP5, and two expressed sequence tags (AA187906 and AA513156). Conclusions: Sequences of four of these genes contained NF-kappa B DNA binding sites of the type that may attract transrepressor p55/p55 NF-kappa B homodimers. Down-regulation of these genes upon UV irradiation may contribute to increased cell survival via suppression of p53 independent apoptosis. C1 Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. Argonne Natl Lab, Elect & Comp Technol Div, Argonne, IL 60439 USA. RP Woloschak, GE (reprint author), Argonne Natl Lab, Biosci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Paunesku, Tatjana/A-3488-2017; Woloschak, Gayle/A-3799-2017 OI Paunesku, Tatjana/0000-0001-8698-2938; Woloschak, Gayle/0000-0001-9209-8954 FU NCI NIH HHS [CA73042]; NIEHS NIH HHS [ES07141]; NINDS NIH HHS [5P50 NS21442] NR 54 TC 8 Z9 8 U1 0 U2 0 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 FEB PY 2000 VL 76 IS 2 BP 189 EP 198 PG 10 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 284GM UT WOS:000085323300006 PM 10716640 ER PT J AU Durbin, PW Kullgren, B Xu, J Raymond, KN AF Durbin, PW Kullgren, B Xu, J Raymond, KN TI Multidentate hydroxypyridinonate ligands for Pu(IV) chelation in vivo: comparative efficacy and toxicity in mouse of ligands containing 1,2-HOPO or Me-3,2-HOPO SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID SIMULATED WOUND CONTAMINATION; ION SEQUESTERING AGENTS; IN-VIVO; INJECTED PU-238; DFO-HOPO; 3,4,3-LIHOPO; RAT; MICE; ACTINIDES; PLUTONIUM AB Purpose: To identify the most effective multidentate 1,2-HOPO and Me-3,2-HOPO ligands For chelation of Pu(IV) in vivo. Materials and methods: Two sets of ligands with four identical backbones were prepared containing two, three or four bidentate 1,2-HOPO or Me-3,2-HOPO groups, and 3,4,3-LI(1,2-HOPO) was resynthesized in a higher yielding procedure. They were evaluated in mouse for acute toxicity and reduction of tissue (238)pu, in comparison with CaNa3-DTPA (30 mu mol kg(-1)). Results: Nine HOPO ligands, promptly injected or given orally or injected at low dosage, are superior to CaNa3-DTPA for reducing (238)pU retention in mouse. Five, given by delayed injection or promptly injected or orally administered as ferric complexes, are superior to CaNa3-DTPA or FeNa2-DTPA respectively. The Me-3,2-HOPO ligands are more effective than their structural 1,2-HOPO analogues, demonstrating the greater affinity of Me-3,2-HOPO for Pu(IV) in vivo. Conclusions: The most efficacious ligand, 3,4,3-LI(1,2-HOPO), contains the less stably binding 1,2-HOPO group; therefore, its linear spermine backbone must confer advantages for Pu(IV) binding (greater solubility, more favorable arrangement of ligating groups, more flexible backbone). Effective low toxicity tetradentate 5-LIO(Me-3,2-HOPO) and hexadentate TREN-(Me-3,2-HOPO) and highly effective but moderately toxic 3,4,3-LI(1,2-HOPO) (LD50 similar to 300 mu molkg(-1) in mouse) are recommended for further investigation. C1 Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Durbin, PW (reprint author), Lawrence Berkeley Natl Lab, Div Chem Sci, Room 1150,Bldg 70A,1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NIEHS NIH HHS [ES02698] NR 40 TC 23 Z9 24 U1 1 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 FEB PY 2000 VL 76 IS 2 BP 199 EP 214 PG 16 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 284GM UT WOS:000085323300007 PM 10716641 ER PT J AU Saji, R Konno, H AF Saji, R Konno, H TI Dynamical features of the local fractal dimension of brain waves and its applicability for diagnosis of senile dementia SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article DE brain waves; electroencephalogram; local fractal dimension; stochastic process; beta distribution AB We have studied local irregularity of brain waves using "local fractal dimensions (LFDs)" for two groups of elderly people, one healthy and the other affected by senile dementia. It is determined that (a) the probability distribution of the LFDs for both groups is subject to the universal law of the beta distribution; (b) the stochastic processes of LFDs of the two groups show a marked difference. We have demonstrated the applicability of the present statistical method based on the LFD for estimating the degree of progression of dementia. C1 Univ Tsukuba, Grad Sch Adv Engn Syst, Tsukuba, Ibaraki 3058573, Japan. Univ Tsukuba, Inst Engn Mech & Syst, Tsukuba, Ibaraki 3058573, Japan. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Saji, R (reprint author), Univ Tsukuba, Grad Sch Adv Engn Syst, Tsukuba, Ibaraki 3058573, Japan. NR 14 TC 4 Z9 4 U1 1 U2 1 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 FEB PY 2000 VL 39 IS 2A BP 679 EP 684 DI 10.1143/JJAP.39.679 PG 6 WC Physics, Applied SC Physics GA 322ZA UT WOS:000087538500064 ER PT J AU Hall, AC Economy, J AF Hall, AC Economy, J TI Preparing high-and low-aspect ratio AIB(2) flakes from borax or boron oxide SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID MECHANICAL-PROPERTIES; COMPOSITES AB The commercial preparation of aluminum-diboride flakes in aluminum relies on relatively expensive starting materials. A new synthesis has been developed that allows AlB2 to be prepared directly from the reaction of borax (Na2B4O7. 10H(2)O) or boron oxide (B2O3) with aluminum. Aluminum metal at temperatures higher than 900 degrees C has been shown to reduce these boron-containing compounds, producing an Al2O3-containing slag and AlB2. A natural separation occurs, leaving AlB2 in the molten aluminum and Al2O3 as part of a slag that forms at the melt surface. Samples containing up to 10 vol.% AlB2 in an aluminum matrix have been directly prepared using this method. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. RP Hall, AC (reprint author), Sandia Natl Labs, POB 5800,Mail Stop 0340, Albuquerque, NM 87185 USA. NR 18 TC 9 Z9 11 U1 0 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD FEB PY 2000 VL 52 IS 2 BP 42 EP 44 DI 10.1007/s11837-000-0046-8 PG 3 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 285KV UT WOS:000085389000005 ER PT J AU Zemskova, SM Haynes, JA Besmann, TM Hunt, RD Beach, DB Golovlev, VN AF Zemskova, SM Haynes, JA Besmann, TM Hunt, RD Beach, DB Golovlev, VN TI Preparation and characterization of some alumosiloxanes as single-source MOCVD precursors for aluminosilicate coatings SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 12th European Conference on Chemical Vapour Deposition CY SEP 05-10, 1999 CL BARCELONA, SPAIN SP Elect Soc, Gen Catalunya Dept Presidencia Comm Univ Recerca, ICMAB, CSIC, ISCAR New Line, INORGTECH, CND AB Alumosiloxanes [Al(OSiMe3)(3)](2), (Me3SiO)(2)Al[OSi(OBu-t)(3)], [(acac)Al(OSiMe3)(2)](2), (OX)Al[OSi(OBu-t)(3)](2), (Me=CH3; Bu-t= t-C4H9; acac = C5H7O2; OX = C9H6NO) have been synthesized and their thermal properties have been studied by thermogravimetric analysis in Ar over the temperature range of 25-500 degrees C. The compounds [Al(OSiMe3)(3)](2) and [(acac)Al(OSiMe3)(2)](2) showed substantial volatility during heating regardless of their dimeric structures in the solid state; while the other compounds were largely decomposed under the same conditions. Therefore, [Al(OSiMe3)(3)](2) and [(acac)Al(OSiMe3)(2)](2) have been chosen as prospective precursors for the MOCVD of aluminosilicate coatings. Investigation of these compounds by laser mass-spectrometry (laser excitation at 355nm) has shown that the decomposition pathway proceeds through the formation of a number of heavy species originating from dimeric [>Al<(OSi)(2)>Al<] fragments of [Al(OSiMe3)(3)](2) and [(acac)Al(OSiMe3)(2)](2) molecules and silicon-containing light species of m/z 52 (C2Si) and 55(C2H3Si) originating from OSiMe3 ligands. Initial experiments have been carried out on the deposition of aluminosilicate coatings on silicon carbide from the precursors described. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Zemskova, SM (reprint author), Oak Ridge Natl Lab, POB 2008,1 Bethel Valley Rd, Oak Ridge, TN 37831 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD FEB PY 2000 VL 10 IS P2 BP 35 EP 42 DI 10.1051/jp4:2000205 PG 8 WC Physics, Multidisciplinary SC Physics GA 290ZP UT WOS:000085708000005 ER PT J AU Lehmberg, RH Rothenberg, JE AF Lehmberg, RH Rothenberg, JE TI Comparison of optical beam smoothing techniques for inertial confinement fusion and improvement of smoothing by the use of zero-correlation masks SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INDUCED SPATIAL INCOHERENCE; NIKE KRF LASER; 3RD-HARMONIC GENERATION; PROFILES; ILLUMINATION; UNIFORMITY; SYSTEM; LIGHT AB We present analytic theory and numerical simulations comparing the optical beam smoothing capabilities of the smoothing by spectral dispersion (SSD) technique using random temporal phase modulation, with that of the induced spatial incoherence technique. The analytic theory provides a simple formula for the SSD mode spectrum in the usual case where the phase mask at the focusing lens is random, and its asymptotic limit quantitatively relates the long wavelength mode smoothing to the width of the angular dispersion. With parameters and phase aberration relevant to the National Ignition Facility beams, the SSD simulations show that the large long wavelength components, which are also found in earlier simulations, can be significantly reduced by replacing the independent random phase masks in each pair of adjacent beams by a conjugate pair of zero-correlation masks. These simulations suggest that one can combine zero-correlation masks with random temporal phase modulation and multiple color cycles to achieve SSD smoothing approaching the optical bandwidth limit at all spatial frequencies, without using large angular dispersions. (C) 2000 American Institute of Physics. [S0021-8979(00)02103-4]. C1 USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Lehmberg, RH (reprint author), USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. NR 34 TC 12 Z9 12 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 FEB 1 PY 2000 VL 87 IS 3 BP 1012 EP 1022 DI 10.1063/1.371973 PG 11 WC Physics, Applied SC Physics GA 275LV UT WOS:000084822400003 ER PT J AU Wei, SH Zhang, SB Zunger, A AF Wei, SH Zhang, SB Zunger, A TI First-principles calculation of band offsets, optical bowings, and defects in CdS, CdSe, CdTe, and their alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SPECIAL QUASIRANDOM STRUCTURES; II-VI; DEFORMATION POTENTIALS; SEMICONDUCTOR ALLOYS; SOLID-SOLUTIONS; D-ORBITALS; FILMS; DISORDER; DENSITY; GAASN AB Using first principles band structure theory we have calculated (i) the alloy bowing coefficients, (ii) the alloy mixing enthalpies, and (iii) the interfacial valence band offsets for three Cd-based (CdS, CdSe, CdTe) compounds. We have also calculated defect formation energies and defect transition energy levels of Cd vacancy V-Cd and Cu-Cd substitutional defect in CdS and CdTe, as well as the isovalent defect Te-S in CdS. The calculated results are compared with available experimental data. (C) 2000 American Institute of Physics. [S0021-8979(00)01103-8]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Natl Renewable Energy Lab, Golden, CO 80401 USA. EM swei@nrel.gov RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 63 TC 225 Z9 228 U1 19 U2 101 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 FEB 1 PY 2000 VL 87 IS 3 BP 1304 EP 1311 DI 10.1063/1.372014 PG 8 WC Physics, Applied SC Physics GA 275LV UT WOS:000084822400045 ER PT J AU Fernandez, A Cerjan, CJ AF Fernandez, A Cerjan, CJ TI Nucleation and annihilation of magnetic vortices in submicron-scale Co dots SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SWITCHING FIELD; COBALT ISLANDS; LITHOGRAPHY; NANOSTRUCTURES AB We describe experiments on arrays of polycrystalline Co structures fabricated by interference lithography. The dots are thin (15-40 nm), submicron in size, and are patterned with a uniaxial, in-plane, shape anisotropy axis. We use magnetic force microscopy (MFM) in the presence of an applied field to directly observe magnetic reversal in the dots. These experiments reveal that reversal occurs predominantly through the nucleation and annihilation of a single magnetic vortex in each dot. Hysteresis loop measurements indicate that the vortices are stable over a wide range of applied fields and that the limits of this range depend on the size and thickness of the dots. Using the MFM data, we determine the statistical distribution of the single-vortex nucleation field for several different arrays. We attribute the observed variance to the random orientation of the polycrystalline grains. Finally, we show that the average vortex nucleation and annihilations fields are linearly correlated to the demagnetization field of a uniformly magnetized structure. (C) 2000 American Institute of Physics. [S0021-8979(00)03103-0]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Fernandez, A (reprint author), Etec Syst Inc, 26460 Corp Ave, Hayward, CA 94545 USA. NR 15 TC 85 Z9 85 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 FEB 1 PY 2000 VL 87 IS 3 BP 1395 EP 1401 DI 10.1063/1.372026 PG 7 WC Physics, Applied SC Physics GA 275LV UT WOS:000084822400058 ER PT J AU Derenzo, SE Klintenberg, MK Weber, MJ AF Derenzo, SE Klintenberg, MK Weber, MJ TI Determining point charge arrays that produce accurate ionic crystal fields for atomic cluster calculations SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYSTEMS AB In performing atomic cluster calculations of local electronic structure defects in ionic crystals, the crystal is often modeled as a central cluster of 5-50 ions embedded in an array of point charges. For most crystals, however, a finite three-dimensional repeated array of unit cells generates electrostatic potentials that are in significant disagreement with the Madelung (infinite crystal) potentials computed by the Ewald method. This is illustrated for the cubic crystal CaF2. We present a novel algorithm for solving this problem for any crystal whose unit cell information is known: (1) the unit cell is used to generate a neutral array containing typically 10 000 point charges at their normal crystallographic positions; (2) the array is divided into zone 1 (a volume defined by the atomic cluster of interest), zone 2 (several hundred additional point charges that together with zone 1 fill a spherical volume), and zone 3 (all other point charges); (3) the Ewald formula is used to compute the site potentials at all point charges in zones 1 and 2; (4) a system of simultaneous linear equations is solved to find the zone 3 charge values that make the zone 1 and zone 2 site potentials exactly equal to their Ewald values and the total charge and dipole moments equal to zero, and (5) the solution is checked at 1000 additional points randomly chosen in zone 1. The method is applied to 33 different crystal types with 50-71 ions in zone 1. In all cases the accuracy determined in step 5 steadily improves as the sizes of zones 2 and 3 are increased, reaching a typical rms error of 1 mu V in zone 1 for 500 point charges in zone 2 and 10 000 in zone 3. (C) 2000 American Institute of Physics. [S0021-9606(00)30103-9]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Ctr Funct Imaging, Berkeley, CA 94720 USA. RP Derenzo, SE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Ctr Funct Imaging, Berkeley, CA 94720 USA. NR 14 TC 46 Z9 46 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 2000 VL 112 IS 5 BP 2074 EP 2081 DI 10.1063/1.480776 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 277NR UT WOS:000084940100003 ER PT J AU Cho, MH Blank, DA Sung, J Park, K Hahn, S Fleming, GR AF Cho, MH Blank, DA Sung, J Park, K Hahn, S Fleming, GR TI Intrinsic cascading contributions to the fifth- and seventh-order electronically off-resonant Raman spectroscopies SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FEMTOSECOND 2-DIMENSIONAL SPECTROSCOPY; 5TH-ORDER NONLINEAR SPECTROSCOPY; TIME-RESOLVED 4-WAVE; LIQUID CS2; VIBRATIONAL-MODES; ECHO EXPERIMENTS; CONDENSED-PHASE; SCATTERING; MECHANISMS; MIXTURE AB The cascading polarization contributing to the femtosecond fifth- and seventh-order coherent Raman scattering processes is obtained in terms of the third- and fifth-order Raman response functions. It is found that four cascading processes contribute to the fifth-order Raman scattering signal. In the case of the seventh-order Raman scattering, there are 34 possible cascading processes contributing to the seventh-order Raman scattering signal, and they are classified as chi((5))x chi((3))- and chi((3))x chi((3))x chi((3))-types depending on the involved low-order nonlinear optical processes. Due to the complicated interference among these polarization fields, it may not be possible to experimentally measure the pure seventh-order Raman scattering signal without contamination from the cascaded contributions. (C) 2000 American Institute of Physics. [S0021-9606(00)00104-5]. C1 Korea Univ, Dept Chem, Seoul 136701, South Korea. Korea Univ, Ctr Electro & Photorespons Mol, Seoul 136701, South Korea. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Cho, MH (reprint author), Korea Univ, Dept Chem, Seoul 136701, South Korea. RI Park, Kisam/B-1372-2009 NR 37 TC 46 Z9 46 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 FEB 1 PY 2000 VL 112 IS 5 BP 2082 EP 2094 DI 10.1063/1.480777 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 277NR UT WOS:000084940100004 ER PT J AU Tilson, JL Shepard, R Naleway, C Wagner, AF Ermler, WC AF Tilson, JL Shepard, R Naleway, C Wagner, AF Ermler, WC TI Ab initio determination of americium ionization potentials SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RELATIVISTIC EFFECTIVE POTENTIALS; SPIN-ORBIT OPERATORS; ELECTRON; ENERGIES; CORE AB The first three ionization potentials of americium are calculated using ab initio spin-orbit configuration interaction techniques. These results are favorably compared to available experimental and previous theoretical work. The lowest two ionization potentials are accurately determined using wave functions constructed as simple single and double substitutions from a self-consistent field reference configuration with scalar relativistic effects included through an averaged relativistic pseudopotential. A determination of the third ionization potential to comparable accuracy requires inclusion of the spin-orbit operator and significant intermediate coupling with a resulting configuration expansion length in excess of 1.9 million double-group adapted functions. The solution to this problem was achieved by application of a new parallel spin-orbit configuration interaction component to the COLUMBUS Program System. A decomposition of the ionization potential calculation into parts either sensitive or largely insensitive to the spin-orbit operator is favorably tested, leading to hybrid calculations of improved accuracy. (C) 2000 American Institute of Physics. [S0021-9606(00)30303-8]. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Stevens Inst Technol, Dept Chem & Biol Chem, Hoboken, NJ 07030 USA. RP Tilson, JL (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ermler, Walter/B-6876-2011 NR 37 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 2000 VL 112 IS 5 BP 2292 EP 2300 DI 10.1063/1.480793 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 277NR UT WOS:000084940100028 ER PT J AU Parks, EK Kerns, KP Koretsky, GM Nieman, GC Riley, SJ AF Parks, EK Kerns, KP Koretsky, GM Nieman, GC Riley, SJ TI The decomposition of C-60 on nickel clusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID METAL-COATED FULLERENES; THERMAL-STABILITY; MOLECULAR-OXYGEN; ADSORPTION; CHEMISORPTION; FRAGMENTATION; SURFACES; PT(111); NI(110); RAMAN AB The adsorption of C-60 on nickel clusters Ni-n in the n = 8-31 size range is studied at elevated temperatures. Above 800 degrees C, decomposition of C-60 is seen on clusters containing oxide impurities by the loss of CO and/or CO2 molecules. The extent of decomposition depends on cluster size and C-60 coverage, which affect the charging of the metal core by electron transfer from the metal to the C-60. Both decreased cluster size and increased C-60 coverage reduce the electron transfer per C-60 molecule, weakening the C-60-Ni-n bond and decreasing the rate of decomposition. In spite of this effect, C-60 appears to decompose more readily on small nickel clusters than on bulk nickel surfaces. While decomposition is only observed for clusters having adsorbed O atoms, the oxygen may actually inhibit decomposition by withdrawing electronic charge from the metal, likewise weakening the C-60-Ni-n bond. (C) 2000 American Institute of Physics. [S0021-9606(00)70105-X]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Monmouth Coll, Dept Chem, Monmouth, IL 61462 USA. RP Parks, EK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 29 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 2000 VL 112 IS 5 BP 2479 EP 2485 DI 10.1063/1.480813 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 277NR UT WOS:000084940100050 ER PT J AU Derrendinger, L Sposito, G AF Derrendinger, L Sposito, G TI Flocculation kinetics and cluster morphology in illite/NaCl suspensions SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE flocculation of illite; fractal clusters; light scattering; scaling invariance in flocculation; universality classes ID LIMITED COLLOID AGGREGATION; ORGANIC-MATTER ROLE; FRACTAL DIMENSION; LIGHT-SCATTERING; HUMIC ACIDS; DIFFUSION; UNIVERSALITY; CHARGE; COAGULATION; BEHAVIOR AB Using static and dynamic light-scattering techniques, we investigated the flocculation of geologic specimen illite and soil illite colloids suspended in NaCl solution at pH 8, Our results show that the two universality classes proposed by Lin and co-workers to characterize the diffusion and reaction-limited regimes of cluster-cluster flocculation do not apply to illite colloids, which have nonspherical morphology. Static light-scattering measurements yielded mass fractal dimensions for the soil illite clusters that were significantly above those required by universality. Those for specimen illite were influenced by the initial colloid concentration, suggesting that cluster restructuring had occurred during flocculation. Dynamic light-scattering measurements revealed a significant departure from linear growth of the mean cluster size with time, as required by universality in the diffusion-limited regime, and, for specimen illite, an oscillatory dependence of the mean cluster radius on time was observed in the transition from diffusion-limited to reaction-limited flocculation, Overall, the morphology, interactions, and restructuring of primary particles are believed to be responsible for the departure from universality in the flocculation behavior of the illite colloids. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Ecosyst Sci Div, Berkeley, CA 94720 USA. RP Derrendinger, L (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Bldg 815, Upton, NY 11973 USA. NR 50 TC 7 Z9 11 U1 1 U2 9 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD FEB 1 PY 2000 VL 222 IS 1 BP 1 EP 11 DI 10.1006/jcis.1999.6606 PG 11 WC Chemistry, Physical SC Chemistry GA 281PB UT WOS:000085168900001 ER PT J AU Hu, MZC Payzant, EA Byers, CH AF Hu, MZC Payzant, EA Byers, CH TI Sol-gel and ultrafine particle formation via dielectric tuning of inorganic salt-alcohol-water solutions SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE sol-gel; homogeneous precipitation; nucleation; growth; monodispersed; powders; microspheres; nanospheres; zirconia; solution synthesis; hydrothermal ID HYDROLYSIS; OXIDE AB Under some conditions, inorganic salts can be as good precursors for sol-gel-type processing as those obtained from expensive metalloorganic precursors such as alkoxides. In this work, the formation of monodispersed hydrous zirconia microsphere particles (particularly nanosized) and gels was achieved in solutions of zirconyl chloride dissolved in alcohol-water mixed solvents. The dielectric property of the mixed alcohol-water solvent directly affects the nucleation and growth of zirconia clusters/particles in homogeneous solutions. A lower dielectric constant of mixed solvent corresponds to a lower solubility of inorganic solute and, thus, a shorter induction period for nucleation as well as higher solid particle growth kinetics. Dynamic light scattering (DLS) was used to monitor the homogeneous nucleation and growth processes, while final particles and gels were studied by scanning electron microscopy (SEM) and high-temperature X-ray diffraction (HTXRD). The sol-get processes in the mixed solvent system can be adjusted using the processing parameters, including the initial inorganic salt concentration (C), alcohol/aqueous medium volume ratio of the mixed solution (RH), incubation temperature (T), incubation time (t), concentration of hydroxypropyl cellulose (HPC), and ammonia neutralization, Monodispersed submicron and nanoscale(< 100 nm) zirconia microspheres/powders were successfully synthesized under conditions of high RH (5) and using HPC (molecular weight of 100,000, 2.0 x 10(-3) g/cm(3)) and ammonia neutralization. Initial salt concentration affects the particle size significantly. Gel materials were obtained under conditions of low RH (1.0). Microstructure and transparency of gels changed significantly from low (0.05 M) to high (0.2 M) concentration of the metal salt. We have also demonstrated that monodispersed particle production can be achieved not only at low temperatures (<100 degrees C) but also at room temperature using an inorganic salt precursor. (C) 2000 Academic Press. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Hu, MZC (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. EM i5h@ornl.gov RI Payzant, Edward/B-5449-2009; OI Payzant, Edward/0000-0002-3447-2060; Hu, Michael/0000-0001-8461-9684 NR 16 TC 47 Z9 52 U1 0 U2 21 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 EI 1095-7103 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD FEB 1 PY 2000 VL 222 IS 1 BP 20 EP 36 DI 10.1006/jcis.1999.6610 PG 17 WC Chemistry, Physical SC Chemistry GA 281PB UT WOS:000085168900003 ER PT J AU Biefeld, RM Phillips, JD AF Biefeld, RM Phillips, JD TI Growth of InSb on GaAs using InAlSb buffer layers SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE metal-organic chemical vapor deposition; epitaxy; electron mobility; InSb ID CHEMICAL-VAPOR-DEPOSITION AB We report the growth of InSb on GaAs using InAlSb buffers of high interest for magnetic field sensors. We have grown samples by metal-organic chemical vapor deposition consisting of similar to 0.55 mu m thick Insb layers with InAlSb buffers on GaAs substrates with measured electron mobilities of similar to 40000 cm(2)/V s. We have investigated the In1-xAlxSb buffers for compositions x less than or equal to 0.22 and have found that the best results are obtained near x = 0.12 due to the tradeoff of buffer layer band gap and lattice mismatch. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Dept 1113, Albuquerque, NM 87185 USA. RP Biefeld, RM (reprint author), Sandia Natl Labs, Dept 1113, Bldg 225,RM 9,1515 Eubank Bldg SE, Albuquerque, NM 87185 USA. RI Phillips, Jamie/E-9394-2010 NR 9 TC 11 Z9 11 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 2000 VL 209 IS 4 BP 567 EP 571 DI 10.1016/S0022-0248(99)00751-4 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 287LZ UT WOS:000085508500001 ER PT J AU Christe, KO Dixon, DA McLemore, D Wilson, WW Sheehy, JA Boatz, JA AF Christe, KO Dixon, DA McLemore, D Wilson, WW Sheehy, JA Boatz, JA TI On a quantitative scale for Lewis acidity and recent progress in polynitrogen chemistry SO JOURNAL OF FLUORINE CHEMISTRY LA English DT Article; Proceedings Paper CT 16th International Conference on Fluorine Chemistry (ICFC 99) CY MAY 09-11, 1999 CL TOKYO, JAPAN SP Japan Soc Promot Sci DE Lewis acidity scale; Ab initio calculations; fluoride affinity calculations; high energy density materials; polynitrogen compounds; synthesis ID FLUORIDE-ION AFFINITIES; CATION; ATOMS; BOND AB A quantitative scale for Lewis acidities based on fluoride ion affinities is discussed. it uses pF(-) values which represent the fluoride ion affinities in kcal/mol divided by 10. These values were obtained for 106 Lewis acids in a self-consistent manner using ab initio calculations at the MP2/PDZ level of theory. In the area of polynitrogen chemistry, the synthesis and characterization of the novel N-5(+) cation from N2F+ and HN3 is described. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ So Calif, Loker Hydrocarbon Res Inst, Dept Chem, Los Angeles, CA 90089 USA. Air Force Res Lab, Prop Sci & Adv Concepts Div, PRS, Edwards AFB, CA 93524 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Christe, KO (reprint author), Univ So Calif, Loker Hydrocarbon Res Inst, Dept Chem, Los Angeles, CA 90089 USA. RI Christe, Karl/O-4885-2014 OI Christe, Karl/0000-0003-0661-5519 NR 18 TC 190 Z9 193 U1 7 U2 40 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-1139 J9 J FLUORINE CHEM JI J. Fluor. Chem. PD FEB PY 2000 VL 101 IS 2 BP 151 EP 153 DI 10.1016/S0022-1139(99)00151-7 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 269QH UT WOS:000084488700002 ER PT J AU Ding, YS AF Ding, YS TI F-18-labeled biomolecules for PET studies in the neurosciences SO JOURNAL OF FLUORINE CHEMISTRY LA English DT Article; Proceedings Paper CT 16th International Conference on Fluorine Chemistry (ICFC 99) CY MAY 09-11, 1999 CL TOKYO, JAPAN SP Japan Soc Promot Sci DE F-18; PET; nucleophilic aromatic substitution; catecholamine; nAChR; COMT ID POSITRON EMISSION TOMOGRAPHY; NUCLEOPHILIC AROMATIC-SUBSTITUTION; F-18 AB F-18, a positron emitting isotope of fluorine, has a half-life of 110 min and a positron energy of 0.635 MeV. Positron emission tomography (PET), in conjunction with appropriate radiotracers labeled with F-18 has been used to assess functional activity, biochemical transformations and drug pharmacokinetics and pharmacodynamics in the human and animal body. The PET method, F-18-labeling of organic molecules, and some of the applications of F-18-labeled compounds in the neurosciences (brain and heart) are described. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Ding, YS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 21 TC 5 Z9 5 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-1139 J9 J FLUORINE CHEM JI J. Fluor. Chem. PD FEB PY 2000 VL 101 IS 2 BP 291 EP 295 DI 10.1016/S0022-1139(99)00173-6 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 269QH UT WOS:000084488700024 ER PT J AU Wang, C Richardson, JD Gosling, JT AF Wang, C Richardson, JD Gosling, JT TI A numerical study of the evolution of the solar wind from Ulysses to Voyager 2 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LARGE HELIOCENTRIC DISTANCES; OUTER HELIOSPHERE; INTERACTION REGIONS; INTERSTELLAR GAS; PIONEER-10; SIMULATION; MODEL; TEMPERATURE; HYDROGEN; AU AB Voyager 2 continues to explore the outer heliosphere as Ulysses studies the latitudinal dependence of the solar wind. During the year 1991 these spacecraft were within 2 degrees latitude and their radial separation was larger than 30 AU. This alignment presents a good opportunity to investigate the evolution of the solar wind and, in particular, the effect of pickup ions, which are an important component of the solar wind in the outer heliosphere. A numerical simulation study is used to model the evolution of solar wind structures from the location of Ulysses (1-5 AU) to Voyager 2 (33-36 AU) in 1891. The Ulysses observations were used as input into the numerical models and the theoretical predictions were compared with the Voyager 2 observations. The model produces profiles and magnitudes of the plasma parameters (e.g., flow speed and density) which are in reasonable agreement with the observations, The inclusion of pickup ions slows the solar wind, reduces the amplitudes of the speed variations and density spikes, and changes the speed of shock propagation. However, within 35 AU, pickup ions do not change the solar wind structures dramatically Our calculations favor a low interstellar neutral hydrogen density, i.e., n(H infinity) = 0.05 cm(-3), for this time period (1991). C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Wang, C (reprint author), MIT, Ctr Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 26 TC 50 Z9 51 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 FEB 1 PY 2000 VL 105 IS A2 BP 2337 EP 2344 DI 10.1029/1999JA900436 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281YP UT WOS:000085189300003 ER PT J AU Carlino, G Konishi, K Murayama, H AF Carlino, G Konishi, K Murayama, H TI Dynamics of supersymmetric SU(n(c)) and USp(2n(c)) gauge theories SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE nonperturbative effects; spontaneous symmetry breaking; global symmetries; supersymmetry and duality ID SUPERCONFORMAL FIELD-THEORIES; ELECTRIC-MAGNETIC DUALITY; YANG-MILLS THEORY; MODULI SPACE; 4 DIMENSIONS; QCD; VACUA; CONFINEMENT; MONOPOLES; SO(N(C)) AB We study dynamical flavor symmetry breaking in the context of a class of N = 1 supersymmetric SU(n(c)) and USp(2n(c)) gauge theories, constructed from the exactly solvable N = 2 theories by perturbing them with small adjoint and generic bare hypermultiplet (quark) masses. We find that the flavor U(n(f)) symmetry in SU(n(c)) theories is dynamically broken to U(r) x U(n(f) - r) groups for n(f) less than or equal to n(c). In the r = 1 case the dynamical symmetry breaking is caused by the condensation of monopoles in the n(f) representation. For general r, however, the monopoles in the <(n(f)C(r))under bar> representation, whose condensation could explain the flavor symmetry breaking but would produce too-many Nambu-Goldstone multiplets, actually "break up" into "magnetic quarks" which condense and induce confinement and the symmetry breaking. In USp(2n(c)) theories with n(f) less than or equal to n(c) + 1, the flavor SO(2n(f)) symmetry is dynamically broken to U(n(f)), but with no description in terms of a weakly coupled local field theory. In both SU(n(c)) and USp(2n(c)) theories, with larger numbers of quark flavors, besides the vacua with these properties, there exist also vacua with no flavor symmetry breaking. C1 Univ Genoa, Dipartimento Fis, I-16146 Genoa, Italy. Ist Nazl Fis Nucl, I-16146 Genoa, Italy. Univ Coll Swansea, Dept Phys, Swansea SA2 8PP, W Glam, Wales. Univ Pisa, Dipartimento Fis, I-56127 Pisa, Italy. Ist Nazl Fis Nucl, I-56127 Pisa, Italy. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Genoa, Dipartimento Fis, Via Dodecaneso 33, I-16146 Genoa, Italy. EM g.carlino@swansea.ac.uk; konishi@phys.washington.edu; murayama@lbl.gov RI Murayama, Hitoshi/A-4286-2011 NR 18 TC 36 Z9 36 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD FEB PY 2000 IS 2 AR 004 DI 10.1088/1126-6708/2000/02/004 PG 17 WC Physics, Particles & Fields SC Physics GA 345FG UT WOS:000088805500004 ER PT J AU Charig, A Kinscherf, K Gargiullo, B Roman, S Connors, TF Unkefer, C Horvath, IT AF Charig, A Kinscherf, K Gargiullo, B Roman, S Connors, TF Unkefer, C Horvath, IT TI Synthesis and characterization of [1,C-14] N-methylneodecanamide SO JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS LA English DT Article AB [1-C-14] N-methylneodecanamide (MNDA), a potent insect-repellent, was synthesized from [1-C-12] neodecanoic acid (NDA) by an exchange variant of the Koch reaction, followed by conversion to the acyl halide and methylamination. The product had all the characteristics of authentic commercial MNDA, and the radiocarbon was distributed among the isomers in the same proportions as the isomers were among the mass. C1 Colgate Palmolive Technol Ctr, Piscataway, NJ USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP Charig, A (reprint author), Colgate Palmolive Technol Ctr, Piscataway, NJ USA. RI Horvath, Istvan/M-8428-2013; Horvath, Istvan/A-6825-2010 OI Horvath, Istvan/0000-0002-6324-186X NR 10 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0362-4803 J9 J LABELLED COMPD RAD JI J. Label. Compd. Radiopharm. PD FEB PY 2000 VL 43 IS 2 BP 177 EP 184 PG 8 WC Biochemical Research Methods; Chemistry, Medicinal; Chemistry, Analytical SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Chemistry GA 277LW UT WOS:000084935900008 ER PT J AU Allayee, H Dominguez, KM Aouizerat, BE Krauss, RM Rotter, JI Lu, JY Cantor, RM de Bruin, TWA Lusis, AJ AF Allayee, H Dominguez, KM Aouizerat, BE Krauss, RM Rotter, JI Lu, JY Cantor, RM de Bruin, TWA Lusis, AJ TI Contribution of the hepatic lipase gene to the atherogenic lipoprotein phenotype in familial combined hyperlipidemia SO JOURNAL OF LIPID RESEARCH LA English DT Article DE familial combined hyperlipidemia; atherogenic lipoprotein phenotype; hepatic lipase; genetic linkage analysis ID CORONARY-ARTERY DISEASE; MEASURED GENOTYPE INFORMATION; TANDEM-REPEAT POLYMORPHISMS; SUBCLASS PATTERNS; APOLIPOPROTEIN-B; QUANTITATIVE PHENOTYPES; HEART-DISEASE; HUMAN GENOME; BUOYANT LDL; CHOLESTEROL AB Familial combined hyperlipidemia (FCH) is a common genetic lipid disorder with a frequency of 1-2% in the population. In addition to the hypercholesterolemia and/or hypertriglyceridemia that affected individuals exhibit, small, dense LDL particles and decreased HDL, cholesterol levels are traits frequently associated with FCH, Recently, we reported that families with FCH and families enriched for coronary artery disease (CAD) share genetic determinants for the atherogenic lipoprotein phenotype (ALP), a profile presenting with small, dense LDL particles, decreased HDL-cholesterol levels, and increased triglyceride levels. Other studies in normolipidemic populations have shown that the hepatic lipase (HL) gene is linked to HDL-cholesterol levels and that a polymorphism within the HL promoter (-514C-->T) is associated with increased HDL-cholesterol levels as well as larger, more buoyant LDL particles. In the present study, we tested whether the HL gene locus also contributes to ALP in a series of Dutch FCH families using nonparametric sibpair linkage analysis and association analysis. Evidence for linkage of LDL particle size (P < 0.019), HDL-cholesterol (P < 0.003), and triglyceride levels (P < 0.026) to the HL gene locus was observed. A genome scan in a subset of these families exhibited evidence for linkage of PPD (LOD = 2.2) and HDL-cholesterol levels (LOD = 1.2) to the HL gene locus as well. The -514C-->T promoter polymorphism was significantly associated (P < 0.0001) with higher HDL-cholesterol levels in the unrelated males of this population, but not in unrelated females. No association was observed between the polymorphism and LDL particle size or triglyceride levels. jlr Our results provide support that ALP is a multigenic trait and suggest that the relationship between small, dense LDL particles, HDL cholesterol, and triglyceride levels in FCH families is due, in part, to common genetic factors. C1 Univ Calif Los Angeles, Dept Microbiol & Mol Genet, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Human Genet, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Pediat, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Calif Berkeley, Div Life Sci, Lawrence Berkeley Natl Lab, Berkeley, CA USA. Steven Spielberg Pediat Res Ctr, Div Med Genet, Los Angeles, CA USA. Acad Hosp Maastricht, Dept Med, NL-6202 HX Maastricht, Netherlands. Acad Hosp Maastricht, Dept Endocrinol, NL-6202 HX Maastricht, Netherlands. RP Lusis, AJ (reprint author), Univ Calif Los Angeles, Dept Microbiol & Mol Genet, Los Angeles, CA 90095 USA. FU NCRR NIH HHS [P41 RR03655]; NHLBI NIH HHS [HL 18574, HL-28481] NR 52 TC 57 Z9 59 U1 0 U2 1 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD FEB PY 2000 VL 41 IS 2 BP 245 EP 252 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 287MR UT WOS:000085510200010 PM 10681408 ER PT J AU Illemassene, M Edelstein, NM Murdoch, KM Karbowiak, M Cavellec, R Hubert, S AF Illemassene, M Edelstein, NM Murdoch, KM Karbowiak, M Cavellec, R Hubert, S TI Site-selective spectroscopy and crystal field analysis of Cm3+ diluted in CsCdBr3 SO JOURNAL OF LUMINESCENCE LA English DT Article DE Cm3+; actinides; excited state absorption; lifetimes; symmetric dimer pair; CsCdBr3 ID EXCITED-STATE ABSORPTION; ANTI-STOKES LUMINESCENCE; UP-CONVERSION; ENERGY-TRANSFER; PAIRS; IONS; CSMGBR3; DYNAMICS; SPECTRA; BROMIDE AB The optical spectroscopy of the Cm-248(3+) ion diluted in the host crystal CsCdBr3 has been investigated by laser selective excitation, excited state absorption, and fluorescence spectroscopy. Three distinct Cm3+ sites were observed. The principal site was assigned to the symmetric dimer center and its electronic structure was studied in detail. Analysis of its spectra resulted in the assignment of 58 energy levels up to 40 300 cm(-1). These measured levels were fitted to the parameters of an empirical Hamiltonian with an rms deviation of 27.3 cm(-1). The lifetimes of the six fluorescing levels have been measured at liquid-helium temperatures. Weak blue I-6(7/2) --> S-8(7/2) upconversion fluorescence was observed when pumping the blue-green S-8(7/2) --> P-6(5/2) absorption transitions of the principal site. It is explained by a phonon-assisted energy transfer mechanism. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Inst Phys Nucl, Grp Radiochim, F-91406 Orsay, France. RP Edelstein, NM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NR 23 TC 11 Z9 11 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2313 J9 J LUMIN JI J. Lumines. PD FEB PY 2000 VL 86 IS 1 BP 45 EP 60 DI 10.1016/S0022-2313(99)00173-8 PG 16 WC Optics SC Optics GA 280KP UT WOS:000085102200006 ER PT J AU Hu, JZ Harper, JK Taylor, C Pugmire, RJ Grant, DM AF Hu, JZ Harper, JK Taylor, C Pugmire, RJ Grant, DM TI Modified spectral editing methods for C-13 CP/MAS experiments in solids SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE C-13 CP/MAS; spectral editing ID NMR-SPECTRA; STATE NMR; CPMAS NMR; FIELD AB The spectral editing approach of Zilm and coworkers utilizes polarization, polarization inversion, and spin depolarization methods for enhancing or suppressing NMR spectral lines in solids. The proposed pulse sequences allow nonprotonated C, CH, CH2, and CH3 types of carbon resonances to be separated from one another and identified accordingly. The former method tentatively separates the nonprotonated C and CH3 peaks with a cutoff shift of 35 ppm. This shift is a reasonable demarcation shift for a preponderance of organic molecules, but exceptions do exist that could constitute a serious drawback in a few instances. The new approach separates the nonprotonated C and CH3 carbon peaks unequivocally using modified pulse sequences similar to those of Zilm. Further, both the CH only and CH2 only spectra, respectively, can be acquired directly from combining so called (+) and (-) sequences using different spectral delay periods and pulse parameters. The (+) and the (-) pulse sequences produce signals for the nonprotonated and methyl carbons that have essentially the same amplitude but opposite phases. These spectra, combined with the previously reported CH3 and nonprontonated C only spectra, offer a complete spectral editing technique for solid samples. Examples of these spectral editing methods are provided for 3-methylglutaric acid, fumaric acid monoethyl ester, and two complex natural products: methyl o-methylpodocarpate and 10-deacetylbaccatin III. (C) 2000 Academic Press. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem Engn, Salt Lake City, UT 84112 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hu, JZ (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RI Hu, Jian Zhi/F-7126-2012 FU NIGMS NIH HHS [GM 08521-37] NR 12 TC 18 Z9 18 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1090-7807 J9 J MAGN RESON JI J. Magn. Reson. PD FEB PY 2000 VL 142 IS 2 BP 326 EP 330 DI 10.1006/jmre.1999.1933 PG 5 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 281MA UT WOS:000085163300014 PM 10648150 ER PT J AU Levin, EM Pecharsky, VK Gschneidner, KA Tomlinson, P AF Levin, EM Pecharsky, VK Gschneidner, KA Tomlinson, P TI Magnetic field and temperature-induced first-order transition in Gd-5(Si1.5Ge2.5): a study of the electrical resistance behavior SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE magnetic phase transitions; electrical resistance; magnetoresistance; magnetic diagram ID RESISTIVITY; MAGNETORESISTANCE; GD-5(SI1.8GE2.2); ER(CO1-XSIX)(2); ALLOYS AB Magnetic field (0-4 T) and temperature dependencies (4.2-320 K) of the electrical resistance of Gd-5(Si1.5Ge2.5), which undergoes a reversible first-order ferromagnetic<->paramagnetic phase transition, have been measured. The electrical resistance of Gd-5(Si1.5Ge2.5) indicates that the magnetic phase transition can be induced by both temperature and magnetic field. The temperature dependence of the electrical resistance, R(T), for heating at low temperatures in the zero magnetic field has the usual metallic character, but at a critical temperature of T-cr = 216 K the resistance shows a similar to 20% negative discontinuity due to the transition from the low-temperature high-resistance state to the high-temperature low-resistance state. The R(T) dependence for cooling shows a similar but positive similar to 25% discontinuity at 198 K. The isothermal magnetic field dependence of the electrical resistance from 212 less than or equal to T less than or equal to 224 K indicates the presence of temperature-dependent critical magnetic fields which can reversibly transform the paramagnetic phase into the ferromagnetic phase and vice versa. The critical magnetic fields diagram determined from the isothermal magnetic field dependencies of the electrical resistance of Gd-5(Si1.5Ge2.5) shows that the FM<->PM transition in zero magnetic field on cooling and heating occurs at 206 and 213 K, respectively. The full isothermal magnetic filed hysteresis for the FM<->PM transition is similar to 2 T, and the isofield temperature gap between critical magnetic fields is similar to 7 K. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Pecharsky, VK (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 18 TC 53 Z9 56 U1 2 U2 9 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 FEB PY 2000 VL 210 IS 1-3 BP 181 EP 188 DI 10.1016/S0304-8853(99)00619-8 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 281PR UT WOS:000085170300024 ER PT J AU Lohstroh, W Schulte, O Felsch, W Klose, F Maletta, H Felcher, GP Lauter, H AF Lohstroh, W Schulte, O Felsch, W Klose, F Maletta, H Felcher, GP Lauter, H TI The fragile magnetic structures of Fe/CeH2-delta multilayers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE metallic multilayers; interlayer exchange coupling; spin structures; neutron reflectometry ID X-RAY; REFLECTOMETER; REFLECTION; SCATTERING; DICHROISM; SURFACES AB Fe/CeH2-delta multilayers exhibit at room temperature evidence of interlayer exchange coupling. Subsequent Fe layers are either parallel or antiparallel to each other, depending on the Fe and CeH2-delta layer thickness. However, when both layers have thickness larger than similar to 15 Angstrom, the antiferromagnetic structure becomes fragmented into domains laterally limited to a few microns, and the magnetic structures become very fragile. Small magnetic fields of a few Oersteds acting on the samples during growth induce helimagnetic configurations which coexist with antiferromagnetic coupling. The magnetic structures can be permanently destroyed by applying magnetic fields larger than 150 Oe. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Gottingen, Inst Phys 1, D-37073 Gottingen, Germany. Argonne Natl Lab, Intense Pulsed Neutron Source, SNS Project, Argonne, IL 60439 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14109 Berlin, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Lohstroh, W (reprint author), Univ Gottingen, Inst Phys 1, Bunsenstr 9, D-37073 Gottingen, Germany. NR 21 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD FEB PY 2000 VL 210 IS 1-3 BP 357 EP 365 DI 10.1016/S0304-8853(99)00760-X PG 9 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 281PR UT WOS:000085170300046 ER PT J AU Lee, CH Yu, KL Lee, MH Huang, JCA Felcher, GP AF Lee, CH Yu, KL Lee, MH Huang, JCA Felcher, GP TI The magnetic depth profile at the interface of a permalloy/Co thin film studied by polarized neutron and X-ray reflectivity SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT International Symposium on Advanced Magnetic Technologies (ISAMT99) CY MAY 24-25, 1999 CL TAIPEI, TAIWAN DE magnetic thin films; X-ray reflectivity; neutron reflectivity ID GIANT MAGNETORESISTANCE; ROUGHNESS AB Polarized neutron and X-ray reflectivity are complementary tools for measuring the magnetic depth profile of a thin film. Tn this experiment, permalloy (Ni80Fe20, 30 nm) thin film was deposited on Al2O3(1 (1) over bar 00) substrates with Co(8 nm)/Mo(18 nm) as buffer layers. The depth profile between the permalloy and Co cannot be determined by X-ray reflectivity alone because the electron densities are too close together. Polarized neutron reflectivity, although available only with limited q range available, can determine the interface roughness between the permalloy and Co layer. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 30043, Taiwan. Natl Tsing Hua Univ, Nucl Sci & Technol Dev Ctr, Nucl Reactor Div, Hsinchu 30043, Taiwan. Natl Cheng Kung Univ, Dept Phys, Tainan 701, Taiwan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Lee, CH (reprint author), Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 30043, Taiwan. OI Lee, Chih-Hao/0000-0002-3898-6421 NR 10 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD FEB PY 2000 VL 209 IS 1-3 BP 110 EP 112 DI 10.1016/S0304-8853(99)00659-9 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 279BD UT WOS:000085022700028 ER PT J AU Purdue, JR Smith, MH Patton, JC AF Purdue, JR Smith, MH Patton, JC TI Female philopatry and extreme spatial genetic heterogeneity in white-tailed deer SO JOURNAL OF MAMMALOGY LA English DT Article DE gene flow; genetic spatial heterogeneity; Odocoileus virginianus; white-tailed deer ID VARIABILITY; POPULATION; DIFFERENTIATION; DISPERSAL AB We examined genetic variability and spatial heterogeneity of maternally (mtDNA) and biparentally (allozymes) inherited genes for a large, widely distributed mammal. White-tailed deer (Odocoileus virginianus) in 6 populations from the coastal plain in Georgia and South Carolina showed high levels of variability and spatial heterogeneity for mtDNA and allozymes. There was little sharing of mtDNA variants among samples separated by 30 to 100 km, and 12 of 13 allozyme loci showed significant differentiation among populations. Spatial genetic heterogeneity was positively correlated with geographical distance as predicted in Wright's isolation by distance model. High spatial heterogeneity is surprising considering the species' physical capacity for moving great distances. Dispersal must be limited, but more so in females because they accounted for only an estimated 13% of total dispersal. Social factors must strongly Limit dispersal in white-tailed deer and probably many other mammals. C1 Illinois State Museum, Zool Sect, Springfield, IL 62703 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Georgia, Inst Ecol, Dept Genet, Athens, GA 30602 USA. Univ Georgia, Sch Forest Resources, Athens, GA 30602 USA. LGL Ecol Res Associates Inc, Bryan, TX 77801 USA. RP Purdue, JR (reprint author), Illinois State Museum, Zool Sect, 1011 E Ash St, Springfield, IL 62703 USA. NR 32 TC 47 Z9 49 U1 1 U2 12 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 USA SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD FEB PY 2000 VL 81 IS 1 BP 179 EP 185 DI 10.1644/1545-1542(2000)081<0179:FPAESG>2.0.CO;2 PG 7 WC Zoology SC Zoology GA 286GP UT WOS:000085435500016 ER PT J AU Holesinger, TG Bingert, JF Teplitsky, M Li, Q Parrella, R Rupich, MP Riley, GN AF Holesinger, TG Bingert, JF Teplitsky, M Li, Q Parrella, R Rupich, MP Riley, GN TI Spatial variations in composition in high-critical-current-density Bi-2223 tapes SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CU-O SYSTEM; HIGH-TC SUPERCONDUCTORS; OXYGEN PARTIAL-PRESSURE; CLAD BSCCO-2223 TAPES; PHASE-STABILITY; TEMPERATURE-DEPENDENCE; CHEMICAL-COMPOSITION; ELECTRON-MICROSCOPY; THIN-FILMS; BI AB A detailed compositional analysis of high-critical-current-density (J(c)) (55 and 65 kA/cm(2) at 77 K) (Bi,Pb)(2)Sr2Ca2Cu3Oy (Bi-2223) tapes was undertaken by energy dispersive spectroscopy in the transmission electron microscope. Structural features were coupled with characteristic compositions of the Bi-2223 phase. The average of all compositional measurements of the Bi-2223 phase was determined to be Bi1.88Pb0.23Sr1.96Ca1.95Cu2.98Oy. However, spatial variations in the Bi-2223 composition and differing phase equilibria were found throughout the filament structure. In particular, a considerable range of Bi-2223 compositions can be found within a single tape, and the lead content of the Bi-2223 phase is significantly depressed in the vicinity of lead-rich phases. The depletion of lead in the Bi-2223 phase around the 3221 phases may be a current-limiting microstructure in these tapes. C1 Univ Calif Los Alamos Natl Lab, Div Sci Mat, Met Grp, MST 6, Los Alamos, NM 87545 USA. Amer Supercond Corp, Westborough, MA 01581 USA. RP Holesinger, TG (reprint author), Univ Calif Los Alamos Natl Lab, Div Sci Mat, Met Grp, MST 6, POB 1663, Los Alamos, NM 87545 USA. NR 58 TC 16 Z9 16 U1 0 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 FEB PY 2000 VL 15 IS 2 BP 285 EP 295 DI 10.1557/JMR.2000.0047 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 282TQ UT WOS:000085235300006 ER PT J AU Leventouri, T Chakoumakos, BC Moghaddam, HY Perdikatsis, V AF Leventouri, T Chakoumakos, BC Moghaddam, HY Perdikatsis, V TI Powder neutron diffraction studies of a carbonate fluorapatite SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SUBSTITUTION; APATITES; HYDROXYAPATITE AB Atomic positional disorder of a single-phase natural carbonate fluorapatite (francolite) is revealed from analysis of the atomic displacement parameters (ADPs) refined from neutron powder diffraction data as a function of temperature and carbonate content. The ADPs of the francolite show a strong disturbance at the P, O3, and F sites. When it is heat treated to partially or completely remove the carbonate, the ADPs as well as the other structural parameters resemble those of a fluorapatite (Harding: pegmatite) that was measured under the same conditions. The various structural changes are consistent with a substitution mechanism whereby-the planar carbonate group replaces a phosphate group and lies on the mirror plane of the apatite structure. C1 Florida Atlantic Univ, Dept Phys, Boca Raton, FL 33431 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Inst Geol & Mineral Explorat, Athens 11527, Greece. RP Leventouri, T (reprint author), Florida Atlantic Univ, Dept Phys, Boca Raton, FL 33431 USA. RI Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 25 TC 26 Z9 27 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 FEB PY 2000 VL 15 IS 2 BP 511 EP 517 DI 10.1557/JMR.2000.0076 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 282TQ UT WOS:000085235300035 ER PT J AU Engstrom, C Madan, A Birch, J Nastasi, M Hultman, L Barnett, SA AF Engstrom, C Madan, A Birch, J Nastasi, M Hultman, L Barnett, SA TI High-temperature stability of epitaxial, non-isostructural Mo/NbN superlattices SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID HARDNESS; LAYERS; GROWTH AB The effect of 1000 degrees C vacuum annealing on the structure and hardness of epitaxial Mo/NbN superlattice thin films was studied. The intensity of superlattice satellite peaks, measured by x-ray diffraction, decreased during annealing while new peaks corresponding to a MoNbN ternary phase appeared. The results are consistent with the Mo-Nb-N phase diagram, which shows no mutual solubility between Mo, NbN, and MoNbN. Even after 3-h anneals and a loss of most of the superlattice peak intensity, the room-temperature hardness was the same as for as-deposited superlattices, The retained hardness suggests that a residual nanocomposite structure is retained even after the formation of the ternary structure. C1 Northwestern Univ, Advanced Coating Technol Grp, Evanston, IL 60201 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL USA. Linkoping Univ, Dept Phys, S-58183 Linkoping, Sweden. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Engstrom, C (reprint author), Northwestern Univ, Advanced Coating Technol Grp, Evanston, IL 60201 USA. RI Barnett, Scott/B-7502-2009; Birch, Jens/M-4794-2016 OI Birch, Jens/0000-0002-8469-5983 NR 11 TC 17 Z9 17 U1 0 U2 8 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 FEB PY 2000 VL 15 IS 2 BP 554 EP 559 DI 10.1557/JMR.2000.0082 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 282TQ UT WOS:000085235300041 ER PT J AU He, XM Walter, KC Nastasi, M AF He, XM Walter, KC Nastasi, M TI Effects of bonding structure on the properties of plasma immersion ion processed diamondlike carbon films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AMORPHOUS HYDROGENATED CARBON; DEPOSITION AB Hydrogenated diamondlike carbon (a-C:H DLC) films were prepared on different substrates by using C2H2-Ar plasma immersion ion processing (PHP), and their bonding structure was modified by changing deposition parameters of the chamber pressure and the gas composition. The influence of the bending structure on the properties of the DLC films was investigated by using ion-beam analysis techniques and Raman, infrared, and ultraviolet/visible spectroscopies and by analyzing the measured properties. The increases in density, hardness, and refractive index were found to correlate with the increase of the sp(3)-bonded structure and the concurrent decrease of both the C-H bonds and the average size of sp(2)-bonded domains in the films. An optimal combination of optical and mechanical properties was highly dependent on the hydrogen status existing in DLC films that can be adjusted by means of modulation of the synthesis parameters. The prepared DLC films exhibited desirable properties, which included a hardness above 28 GPa, a density above 2.3 g cm(-3), a refractive index above 1.94, and band gap energies in the range of 1.8-1.85 eV. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP He, XM (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 26 TC 9 Z9 9 U1 0 U2 0 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 FEB PY 2000 VL 15 IS 2 BP 564 EP 571 DI 10.1557/JMR.2000.0084 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 282TQ UT WOS:000085235300043 ER PT J AU Tentler, D Gustavsson, P Elinder, G Eklof, O Gordon, L Mandel, A Dahl, N AF Tentler, D Gustavsson, P Elinder, G Eklof, O Gordon, L Mandel, A Dahl, N TI A microdeletion in 19q13.2 associated with mental retardation, skeletal malformations, and Diamond-Blackfan anaemia suggests a novel contiguous gene syndrome SO JOURNAL OF MEDICAL GENETICS LA English DT Article DE chromosome 19q13; microdeletion syndrome; fibre-FISH ID ANEMIA AB Diamond-Blackfan anaemia (DBA) is a constitutional red blood cell. hypoplasia which may be associated with a variety of developmental abnormalities, a gene for DBA was recently mapped to chromosome 19q13.2 and subsequently cloned. Analysis of 19q marker alleles in DNA of sporadic DBA cases showed de novo microdeletions in three patients also presenting with mental retardation. We have studied one of these patients and characterised the deletion by fluorescence in situ hybridisation (FISH) to extended DNA fibres. The deletion was shown to be continuous over a 3.2 Mb region and the fibre-FISH analysis showed both chromosomal breakpoints. in combination, the clinical and molecular findings suggest a contiguous gene syndrome with a gene locus for mental retardation and, probably, skeletal malformations included in the deletion. C1 Univ Uppsala, Clin Genet Unit, Dept Genet & Pathol, S-75185 Uppsala, Sweden. Karolinska Inst, Inst Sodersjukhuset, Dept Paediat, Stockholm, Sweden. Karolinska Hosp, Dept Paediat Radiol, S-10401 Stockholm, Sweden. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Dahl, N (reprint author), Univ Uppsala, Clin Genet Unit, Dept Genet & Pathol, S-75185 Uppsala, Sweden. NR 17 TC 18 Z9 18 U1 0 U2 2 PU BRITISH MED JOURNAL PUBL GROUP PI LONDON PA BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON WC1H 9JR, ENGLAND SN 0022-2593 J9 J MED GENET JI J. Med. Genet. PD FEB PY 2000 VL 37 IS 2 BP 128 EP 131 DI 10.1136/jmg.37.2.128 PG 4 WC Genetics & Heredity SC Genetics & Heredity GA 283ZZ UT WOS:000085307100010 PM 10662814 ER PT J AU Loo, BW Meyer-Ilse, W Rothman, SS AF Loo, BW Meyer-Ilse, W Rothman, SS TI Automatic image acquisition, calibration and montage assembly for biological X-ray microscopy SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE acinar cell; automatic image montage assembly; CCD camera; digital imaging microscopy; exocrine pancreas; image processing; microscope calibration; microscopic protein mass measurement; quantitative morphometry; synchrotron; transmission soft X-ray microscopy; zymogen granules ID TIME-DELAY; TRANSMISSION AB We describe a system for the automatic acquisition and processing of digital images in a high-resolution X-ray microscope, including the formation of large-field high-resolution image montages, A computer-controlled sample positioning stage provides approximate coordinates for each high-resolution subimage. Individual subimages are corrected to compensate for time-varying, non-uniform illumination and CCD-related artefacts. They are then automatically assembled into a montage, The montage assembly algorithm is designed to use the overlap between each subimage and multiple neighbours to improve the performance of the registration step and the fidelity of the result. This is accomplished by explicit use of recorded stage positions, optimized ordering of subimage insertion, and registration of subimages to the developing montage. Using this procedure registration errors are below the resolution limit of the microscope (43 nm), The image produced is a seamless, large-field montage at full resolution, assembled automatically without human intervention. Beyond this, it is also an accurate X-ray transmission map that allows the quantitative measurement of anatomical and chemical features of the sample. Applying these tools to a biological problem, we have conducted the largest X-ray microscopical study to date. C1 Univ Calif San Francisco, Bioengn Grad Grp, San Francisco, CA 94143 USA. Univ Calif Berkeley, Bioengn Grad Grp, Berkeley, CA USA. Univ Calif Davis, Sch Med, Davis, CA 95616 USA. Ernest O Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif San Francisco, Dept Physiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Stomatol, San Francisco, CA 94143 USA. RP Loo, BW (reprint author), Genter Corp, 2061 Challenger Dr, Alameda, CA 94501 USA. NR 24 TC 19 Z9 19 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 FEB PY 2000 VL 197 BP 185 EP 201 PN 2 PG 17 WC Microscopy SC Microscopy GA 286RM UT WOS:000085459300007 PM 10652011 ER PT J AU Kwiat, PG Mitchell, JR Schwindt, PDD White, AG AF Kwiat, PG Mitchell, JR Schwindt, PDD White, AG TI Grover's search algorithm: an optical approach SO JOURNAL OF MODERN OPTICS LA English DT Article ID QUANTUM LOGIC; EXPERIMENTAL REALIZATION; IMPLEMENTATION; ENTANGLEMENT; COMPUTATION; COMPUTER AB The essential operations of a quantum computer can be accomplished using solely optical elements, with different polarization or spatial modes representing the individual qubits. We present-a simple all-optical implementation of Grover's algorithm for efficient searching, in which a database of four elements is searched with a single query. By 'compiling' the actual set-up, we have reduced the required number:of optical elements from 24 to only 12. We discuss the extension to large databases, and the limitations of these techniques. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. RP Kwiat, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, P-23,MS-H803, Los Alamos, NM 87545 USA. RI White, Andrew/A-1088-2009 OI White, Andrew/0000-0001-9639-5200 NR 29 TC 105 Z9 108 U1 0 U2 18 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD FEB-MAR PY 2000 VL 47 IS 2-3 BP 257 EP 266 DI 10.1080/09500340008244040 PG 10 WC Optics SC Optics GA 282TL UT WOS:000085234900011 ER PT J AU Schneider, S James, DFV Milburn, GJ AF Schneider, S James, DFV Milburn, GJ TI Quantum controlled-NOT gate with 'hot' trapped ions SO JOURNAL OF MODERN OPTICS LA English DT Article ID COMPUTATIONS AB We present a novel method of performing quantum logic gates in trapped ion quantum computers which does not require the ions to be cooled down to the ground state of their vibrational modes, thereby avoiding one of the principal experimental difficulties encountered in realizing this technology. Our scheme employs adiabatic passages and a phase shift conditional on the phonon number state. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Queensland, Ctr Laser Sci, Dept Phys, St Lucia, Qld 4072, Australia. RP Schneider, S (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI MIlburn, Gerard/B-6381-2008; James, Daniel/B-9805-2009 OI MIlburn, Gerard/0000-0002-5404-9681; James, Daniel/0000-0003-3981-4602 NR 14 TC 21 Z9 21 U1 2 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD FEB-MAR PY 2000 VL 47 IS 2-3 BP 499 EP 505 DI 10.1080/09500340008244055 PG 7 WC Optics SC Optics GA 282TL UT WOS:000085234900026 ER PT J AU Hughes, RJ Morgan, GL Peterson, CG AF Hughes, RJ Morgan, GL Peterson, CG TI Quantum key distribution over a 48 km optical fibre network SO JOURNAL OF MODERN OPTICS LA English DT Article ID PRIVACY AMPLIFICATION; CRYPTOGRAPHY; FIBER AB The secure distribution of the secret random bit sequences known as 'key' material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is a new technique for secure key distribution with single-photon transmissions: Heisenberg's uncertainty principle ensures that act adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal photon states to generate shared key material over multi-kilometre optical fibre paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. Here we report the most recent results of our optical fibre experiment in which we have performed quantum key distribution over a 48 km optical fibre network at Los Alamos using photon interference states with the B92 and BB84 quantum key distribution protocols. C1 Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. RP Hughes, RJ (reprint author), Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. NR 36 TC 169 Z9 190 U1 2 U2 27 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 EI 1362-3044 J9 J MOD OPTIC JI J. Mod. Opt. PD FEB-MAR PY 2000 VL 47 IS 2-3 BP 533 EP 547 DI 10.1080/095003400148367 PG 15 WC Optics SC Optics GA 282TL UT WOS:000085234900029 ER PT J AU Hughes, RJ Buttler, WT Kwiat, PG Lamoreaux, SK Morgan, GL Nordholt, JE Peterson, CG AF Hughes, RJ Buttler, WT Kwiat, PG Lamoreaux, SK Morgan, GL Nordholt, JE Peterson, CG TI Free-space quantum key distribution in daylight SO JOURNAL OF MODERN OPTICS LA English DT Article ID PRIVACY AMPLIFICATION; OPTICAL-FIBER; CRYPTOGRAPHY; PHOTONS; CANNOT AB Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed in orbit. we present a feasibility analysis of surface-to-satellite quantum key generation. C1 Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Phys, P 23,MS H803, Los Alamos, NM 87545 USA. NR 40 TC 33 Z9 36 U1 2 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0950-0340 EI 1362-3044 J9 J MOD OPTIC JI J. Mod. Opt. PD FEB-MAR PY 2000 VL 47 IS 2-3 BP 549 EP 562 DI 10.1080/09500340008244059 PG 14 WC Optics SC Optics GA 282TL UT WOS:000085234900030 ER PT J AU Quirke, JME Hsu, YL Van Berkel, GJ AF Quirke, JME Hsu, YL Van Berkel, GJ TI Ferrocene-based electroactive derivatizing reagents for the rapid selective screening of alcohols and phenols in natural product mixtures using electrospray-tandem mass spectrometry SO JOURNAL OF NATURAL PRODUCTS LA English DT Article ID CHEMICAL DERIVATIZATION; PEPPERMINT OIL; IONIZATION; CHROMATOGRAPHY AB The alcohols and phenols of oil of cloves, lemon oil, rose absolut, and oil of peppermint were derivatized with ferroceneoyl azide to generate their ferroceneoyl carbamates. These derivatives are selectively detected at the attomole level, in nanomolar concentrations by electrospray-tandem mass spectrometry (ES-MS/MS) without the need for sample cleanup. The ES-MS/MS analyses of the four essential oils revealed all the expected alcohols, and, in the case of lemon oil, it detected alpha-terpineol as a trace component that was not readily observed by GC-MS. The ES-MS/MS analyses complements the more conventional GC-MS analysis. The ES-MS method has the advantage of speed, selectivity, and sensitivity over GCMS for detection of a targeted alcohol of a specific mass or structural type. The ES-MS method does not require a chromatographic separation of the components to accomplish its task. In contrast, GC-MS remains the preferred method for the determination of the total constituents of an oil. The ES-MS method may produce artifact ions, especially if the sample is wet and an excess of the ferroceneoyl azide is used; however, the artifacts did not interfere with the analyses. C1 Florida Int Univ, Dept Chem, Miami, FL 33199 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Quirke, JME (reprint author), Florida Int Univ, Dept Chem, Miami, FL 33199 USA. NR 22 TC 30 Z9 30 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0163-3864 J9 J NAT PROD JI J. Nat. Prod. PD FEB PY 2000 VL 63 IS 2 BP 230 EP 237 DI 10.1021/np990407l PG 8 WC Plant Sciences; Chemistry, Medicinal; Pharmacology & Pharmacy SC Plant Sciences; Pharmacology & Pharmacy GA 287KW UT WOS:000085505900015 PM 10691715 ER PT J AU Shouval, HZ Goldberg, DH Jones, JP Beckerman, M Cooper, LN AF Shouval, HZ Goldberg, DH Jones, JP Beckerman, M Cooper, LN TI Structured long-range connections can provide a scaffold for orientation maps SO JOURNAL OF NEUROSCIENCE LA English DT Article DE orientation map; synaptic plasticity; visual cortex; model; lateral connections; natural images ID CAT VISUAL-CORTEX; RECEPTIVE-FIELD PROPERTIES; STRIATE CORTEX; HORIZONTAL CONNECTIONS; OCULAR DOMINANCE; PREFERENCE MAPS; THALAMIC INPUT; SIMPLE CELLS; BCM THEORY; EXPERIENCE AB In the visual cortex of the cat and ferret, it is established that maturation of orientation selectivity is shaped by experience-dependent plasticity. However, recent experiments indicate that orientation maps are remarkably stable and experience-independent. We present a model to account for these seemingly paradoxical results. In this model, a scaffold consisting of non-isotropic lateral connections is laid down in horizontal circuitry before visual experience. These lateral connections provide an experience-independent framework for the developing orientation maps by inducing a broad orientation tuning bias in the model neurons. Experience-dependent plasticity of the thalamocortical connections sharpens the tuning while the preferred orientation of the neurons remains unchanged. This model is verified by computer simulations in which the scaffolds are generated both artificially and inferred from experimental optical imaging data. The plasticity is modeled by the BCM synaptic plasticity rule, and the input environment consists of natural images. We use this model to provide a possible explanation of the recent observation in which two eyes without common visual experience develop similar orientation maps. Finally, we propose an experiment involving the disruption of lateral connections to distinguish this model from models proposed by others. C1 Brown Univ, Dept Neurosci, Providence, RI 02912 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. Brown Univ, Inst Brain & Neural Syst, Providence, RI 02912 USA. Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. RP Shouval, HZ (reprint author), Brown Univ, Dept Neurosci, Box 1843, Providence, RI 02912 USA. NR 49 TC 28 Z9 28 U1 1 U2 2 PU SOC NEUROSCIENCE PI WASHINGTON PA 11 DUPONT CIRCLE, NW, STE 500, WASHINGTON, DC 20036 USA SN 0270-6474 J9 J NEUROSCI JI J. Neurosci. PD FEB 1 PY 2000 VL 20 IS 3 BP 1119 EP 1128 PG 10 WC Neurosciences SC Neurosciences & Neurology GA 278AG UT WOS:000084965300029 PM 10648717 ER PT J AU Shkrob, IA Tadjikov, BM Trifunac, AD AF Shkrob, IA Tadjikov, BM Trifunac, AD TI Magnetic resonance studies on radiation-induced point defects in mixed oxide glasses. I. Spin centers in B2O3 and alkali borate glasses SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; VITREOUS BORON TRIOXIDE; NEUTRON-DIFFRACTION; THERMO-LUMINESCENCE; SPECTROSCOPY; RAMAN; SCATTERING; CRYSTALS; SILICA; RINGS AB Radiation-induced spin centers in vitreous boron trioxide and alkali borate glasses were studied using pulsed electron paramagnetic resonance (EPR). It is shown that electrons and holes in these glasses are trapped on valence alternation defects, undercoordinated oxygen (holes) and overcoordinated oxygen (electrons). The local environment around these defects has major effect on spin parameters of the corresponding spin centers. The electronic and atomic structure of spin-1/2 centers and their diamagnetic precursors is analyzed using semiempirical and ab initio calculations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Shkrob, IA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 60 TC 45 Z9 45 U1 2 U2 14 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 FEB PY 2000 VL 262 IS 1-3 BP 6 EP 34 DI 10.1016/S0022-3093(99)00668-7 PG 29 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 284BX UT WOS:000085311800002 ER PT J AU Shkrob, IA Tadjikov, BM Trifunac, AD AF Shkrob, IA Tadjikov, BM Trifunac, AD TI Magnetic resonance studies on radiation-induced point defects in mixed oxide glasses. II. Spin centers in alkali silicate glasses SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Review ID MOLECULAR-DYNAMICS SIMULATION; TRAPPED-HOLE-CENTERS; ALPHA-QUARTZ; PHASE-SEPARATION; AMORPHOUS SILICA; SODA SILICA; MAS-NMR; SODIUM; LUMINESCENCE; OXYGEN AB Irradiation of alkali silicate glasses results in the formation of metastable spin centers, such as oxygen hole centers (OHC1 and OHC2), silicon peroxy radicals and a silicon dangling bond (E' center). In this work, electron paramagnetic resonance (EPR) and electron nuclear double magnetic resonance (ENDOR) are used to study these spin-1/2 defects. It is shown that in a subset of the OHC1 centers the drop SiO . radical is strongly coupled to a single alkali cation, Thermally activated swinging motion of this cation causes asymmetric T-2 relaxation and changes electron spin echo envelop modulation (ESEEM) spectra. It is argued that trapping of the hole by non-bridging oxygen atoms does not result in the release of a compensating alkali cation. Rather, the O-Alk bond elongates and the whole structure relaxes. This view is supported by semi-empirical and ab initio calculations. The observed axial symmetry of the g-tensor for OHC2 is the result of rapid tunneling of the electron between two degenerate sites with rate (0.2 - 50) x 10(11) s(-1) and activation energy similar to 10 meV. This center is a hole trapped on a tetrahedral >SiO22-:- unit or a planar -SiO2- unit. It is demonstrated that silicon peroxy radicals are not formed by charge trapping. Their generation is temperature-independent and occurs via the decay of self-trapped excitons. It seems likely that the same process yields silicon dangling bond centers. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM shkrob@anlchm.chm.anl.gov NR 109 TC 22 Z9 23 U1 3 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 EI 1873-4812 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD FEB PY 2000 VL 262 IS 1-3 BP 35 EP 65 DI 10.1016/S0022-3093(99)00669-9 PG 31 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 284BX UT WOS:000085311800003 ER PT J AU Smith, KL Blackford, MG Lumpkin, GR Zaluzec, NJ AF Smith, KL Blackford, MG Lumpkin, GR Zaluzec, NJ TI Ion beam-induced amorphisation of freudenbergite SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID IRRADIATION-INDUCED AMORPHIZATION; LEVEL NUCLEAR WASTE; IN-SITU; SYNROC; SODIUM; ZIRCONOLITE; TOPOLOGY; DAMAGE; IMMOBILIZATION; MGO-AL2O3-SIO2 AB Using the HVEM-tandem facility at Argonne National Laboratory, the critical dose of 1.5 MeV Kr+ ions for amorphisation of freudenbergite (D-c (freudenbergite)) at room temperature was found to be 1.6 +/- 0.3 x 10(18) ions m(-2) D-c (freudenbergite) is lower than D-c (zirconolite) and D-c (perovskite) (3.5-5.5 and 3.9-9.2x10(18) ion m(-2), respectively). Freudenbergite can occur in Synroc-C, a titanate wasteform designed for immobilising high level radioactive waste (HLW). In Synroc-C, zirconolite and perovskite will contain the majority of the actinides in HLW. Freudenbergite will contain less than 0.2 wt% actinides but will experience displacement damage due to the alpha decay of actinides in surrounding phases. In agreement with the experimental findings of previous authors, our calculations show that in Synroc-C, freudenbergite will remain crystalline after zirconolite and perovskite have become amorphous. Neither of the two current parameters (structural freedom, for susceptibility to amorphisation, S) for estimating the relative radiation resistance of different phases is capable of predicting the relative radiation resistance of freudenbergite, zirconolite and perovskite. The low D-c of freudenbergite may result from Na+ ions having significantly lower E-d values compared to the other elements in freudenbergite, zirconolite and perovskite, in the electric fields induced by heavy ion irradiation of TEM specimens. If this hypothesis is true, it challenges the assumption that heavy ion irradiation can be used to compare the relative radiation resistance of different phases and will have serious implications for the predictive parameters of radiation resistance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Australian Nucl Sci & Technol Org, Div Mat, Menai, NSW 2234, Australia. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Smith, KL (reprint author), Australian Nucl Sci & Technol Org, Div Mat, PMB 1, Menai, NSW 2234, Australia. EM kls@ansto.gov.au RI Lumpkin, Gregory/A-7558-2008 NR 45 TC 5 Z9 7 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD FEB PY 2000 VL 277 IS 2-3 BP 159 EP 168 DI 10.1016/S0022-3115(99)00210-X PG 10 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800004 ER PT J AU Rest, J Hofman, GL AF Rest, J Hofman, GL TI An alternative explanation for evidence that xenon depletion, pore formation, and grain subdivision begin at different local burnups SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID FISSION-PRODUCT BEHAVIOR; UO2 FUELS; IRRADIATION; MODEL AB In order to interpret the recent observation that xenon depletion, pore formation, and grain subdivision occur successively at increasing local burnups, a rate-theory-based model is used to investigate the nucleation and growth of cavities during low-temperature irradiation of UO2 in the presence of irradiation-induced interstitial-loop formation and growth. Consolidation of the dislocation structure takes into account the generation of forest dislocations and capture of interstitial dislocation loops. The loops accumulate and ultimately evolve into a low-energy cellular dislocation structure. The cell walls have been previously identified as recrystallization nuclei. The calculations indicate that nanometer-size bubbles are associated with this cellular dislocation structure while the observed micron-size bubbles are presumed to be either preexisting pores deformed by adjacent grains and/or new pores formed in the new recrystallized grain-boundary junctions. Subsequent to recrystallization, gas released from the recrystallized grains feeds the preexisting pores and the recrystallized grains may appear to form a preferential concentration of subdivided grains around the growing pores. This picture is illustrated in a sequence of photomicrographs of irradiated U3O8. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Rest, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 29 Z9 29 U1 3 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 FEB PY 2000 VL 277 IS 2-3 BP 231 EP 238 DI 10.1016/S0022-3115(99)00201-9 PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800013 ER PT J AU Lillard, RS Willcutt, GJ Pile, DL Butt, DP AF Lillard, RS Willcutt, GJ Pile, DL Butt, DP TI The corrosion of Alloy 718 during 800 MeV proton irradiation SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ELECTRICAL-CONDUCTIVITY; RADIOLYSIS; WATER; MGAL2O4 AB The real-time polarization resistance of Alloy 718 during high energy proton irradiation (rneasureJ with electrochemical impedance spectroscopy) decreased from 1.7 x 10(3) ohm m(2) in the absence of irradiation to 8.2 ohm m(2) at a proton beam current of 0.4 mA. Because the proton beam spot size was smaller than the sample (that is, proton flux decreased radially from the beam center), two methods for determing corrosion rate from polarization resistance were employed. The first method assumed that the distribution of corrosion was uniform across the entire probe surface. With this assumption, the corrosion rate was found to vary from 0.041 mu m/yr at an average proton current of 0.001 mA-3.1 mu m/yr at an average proton current of 0.40 mA. The second method used proton flux as a criterion for determining the area of highest damage. At a peak proton flux of 1.77 x 10(18) p/m(2)s, calculated at an average proton current of 0.40 mA, the corrosion rate was 60.9 mu m/yr. These results are discussed within the context of water radiolysis and direct 718/proton interactions. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, Los Alamos, NM 87545 USA. RP Lillard, RS (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, MST-6,POB 1663,MS G755, Los Alamos, NM 87545 USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 23 TC 7 Z9 7 U1 0 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 FEB PY 2000 VL 277 IS 2-3 BP 250 EP 262 DI 10.1016/S0022-3115(99)00196-8 PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800015 ER PT J AU Byun, TS Kim, SH Lee, BS Kim, IS Hong, JH AF Byun, TS Kim, SH Lee, BS Kim, IS Hong, JH TI Estimation of fracture toughness transition curves of RPV steels from ball indentation and tensile test data SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID PRESSURE-VESSEL STEELS; LOW-ALLOY STEEL; CLEAVAGE FRACTURE; STRESS TRIAXIALITY; WELD METAL; TEMPERATURE; INITIATION; SPECIMENS; BEHAVIOR; MODEL AB It was attempted to estimate the fracture toughness transition curves of reactor pressure vessel (RPV) steels from the ball indentation and tensile test data using the indentation energy to fracture (IEF) model and the relationships describing the effect of stress state on fracture. In the IEF model the fracture toughness is expressed as a function of the ball indentation test parameters and critical mean contact pressure. From the relationships among the stress components the fracture stress is derived as a function of stress triaxiality and flow property. In this approach the fracture stress calculated for the stress triaxiality of indentation deformation is assumed as the critical mean contact pressure. Indentation and tensile tests were performed on six RPV steels at transition temperatures of -160-25 degrees C. The values of critical mean contact pressure were in the range 2500-2500 MPa, The temperature dependence of the estimated fracture toughness, K-JC , agreed well with that obtained by the master curve method of ASTM E 1921 using three-point bend (TPB) specimens. In addition, the critical fracture stresses were obtained by considering the stress triaxiality for the crack tip. All test materials revealed the values of the critical fracture stress ranging from 2100 to 2500 MPa. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Korea Atom Energy Res Inst, Reactor Mat Dept, Taejon 305600, South Korea. Korea Adv Inst Sci & Technol, Dept Nucl Engn, Yusong Gu, Taejon 305701, South Korea. RP Byun, TS (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008,Bldg 5500,MS-6376, Oak Ridge, TN 37831 USA. NR 33 TC 22 Z9 23 U1 0 U2 7 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 FEB PY 2000 VL 277 IS 2-3 BP 263 EP 273 DI 10.1016/S0022-3115(99)00197-X PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800016 ER PT J AU Veilleux, JM El-Genk, MS Chamberlin, EP Munson, C FitzPatrick, J AF Veilleux, JM El-Genk, MS Chamberlin, EP Munson, C FitzPatrick, J TI Etching of UO2 in NF3 RF plasma glow discharge SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID SILICON AB A series of single effect, RF plasma, glow discharge experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. In the experiments, the plasma absorbed power was varied from 25 to 210 W and the pressure from similar to 10 to 40 Pa. The results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 100 W with initial etch rates ranging from 0.2 to 7.4 mu m/min. A primary etch mechanism is proposed in which F atoms created in the plasma diffuse to the UO2 surface and react to form successive intermediates of uranium fluorides and/or oxyfluorides with reactions continuing to form volatile UF6 which desorbs into the gas phase to be pumped away. Ions created in the plasma are too low in concentration to be the primary etch mechanism, yet they can deliver enough energy to enhance the reaction process. UO2 etching is a self-limiting process due to the formation of non-volatile uranium oxyfluorides and fluorides which form over the UO2 surface, slowing or completely blocking the reaction to UF6. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, EWST, Los Alamos, NM 87544 USA. Univ New Mexico, Inst Space Nucl Power Studies, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. RP Veilleux, JM (reprint author), Univ Calif Los Alamos Natl Lab, EWST, MS J514, Los Alamos, NM 87544 USA. NR 25 TC 12 Z9 12 U1 0 U2 2 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 FEB PY 2000 VL 277 IS 2-3 BP 315 EP 324 DI 10.1016/S0022-3115(99)00154-3 PG 10 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800021 ER PT J AU Keiser, DD Abraham, DP Richardson, JW AF Keiser, DD Abraham, DP Richardson, JW TI Influence of technetium on the microstructure of a stainless steel-zirconium alloy SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID CHEMISTRY; PHASE AB Stainless steel-zirconium alloys are being developed for the disposal of metallic waste generated during the electrometallurgical treatment of spent Experimental Breeder Reactor (EBR-II) fuel. The metallic waste contains the fission product technetium, which must be incorporated into a stable waste form matrix to prevent its release into the environment. The baseline waste form for metallic waste from EBR-II fuels is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. The microstructure of SS-15Zr alloys containing 2 wt% technetium was characterized using a combination of microscopy, spectroscopy, diffraction, and chemical analysis techniques. Peaks corresponding to the iron solid solutions ferrite and austenite, ZrFe2-type Laves polytypes C36 and C15, and an Fe23Zr6-type intermetallic were identified in diffraction patterns of the alloy. Discrete technetium-rich phases were not observed either in diffraction patterns or in the microstructure; the element partitioned into various phases of the SS-15Zr alloy. Technetium favors ferrite and austenite over the Zr-based intermetallics. The lattice parameters of the Zr-based intermetallics are smaller than those in an alloy without technetium, which appears to substitute at the zirconium sites of the intermetallic lattice. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Argonne Natl Lab W, Idaho Falls, ID 83403 USA. RP Abraham, DP (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM abraham@cmt.anl.gov NR 16 TC 20 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD FEB PY 2000 VL 277 IS 2-3 BP 333 EP 338 DI 10.1016/S0022-3115(99)00158-0 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 277YH UT WOS:000084960800023 ER PT J AU You, H AF You, H TI X-ray scattering study of soft-optic-mode freezing in lead magnesium niobate single crystals SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Williamsburg Workshop on Ferroelectrics 99 CY JAN 31-FEB 03, 1999 CL WILLIAMSBURG, VIRGINIA SP Off Naval Res DE PMN ID PBMG1/3NB2/3O3; DIFFRACTION AB An elementary scattering equation is derived to show that diffuse X-ray scattering intensity near a Bragg reflection can be attributed either entirely to optic modes or to acoustic modes in simple cases. It is used to ascertain that the observed diffuse scattering near odd-integer reflections originates from [110] transverse optic modes. Detailed temperature-dependent measurements reveal that, unlike usual phase transition, freezing of the optic mode is dispersive. That is, the freezing temperature increases with q. At temperatures lower than similar to 173 K, the modes of all length scale freeze to form a statically distorted structure. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP You, H (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI You, Hoydoo/A-6201-2011 OI You, Hoydoo/0000-0003-2996-9483 NR 21 TC 13 Z9 13 U1 0 U2 0 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 FEB PY 2000 VL 61 IS 2 BP 215 EP 220 DI 10.1016/S0022-3697(99)00284-X PG 6 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 263VY UT WOS:000084147000012 ER PT J AU Gosula, V Tkachuk, A Chung, K Chen, H AF Gosula, V Tkachuk, A Chung, K Chen, H TI X-ray scattering study of the transition dynamics in relaxer ferroelectric Pb(Mg1/3Nb2/3)O-3 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Williamsburg Workshop on Ferroelectrics 99 CY JAN 31-FEB 03, 1999 CL WILLIAMSBURG, VIRGINIA SP Off Naval Res DE X-ray diffraction; crystal structure; ferroelectricity; phase transitions ID LEAD MAGNESIUM NIOBATE; STRUCTURAL PHASE-TRANSITIONS; PBMG1/3NB2/3O3 CERAMICS; CRYSTAL-STRUCTURE; RAMAN-SCATTERING; PEROVSKITE; RB1-X(NH4)XH2PO4; DIFFRACTION; DISORDER; BEHAVIOR AB Results of a series of synchrotron radiation scattering studies of a Pb(Mg1/3Nb2/3)O-3 (PMN) single crystal are presented. The temperature dependence of the 1:1 chemical short-range order (SRO) peaks, e.g. 1/2(115), was studied in detail from 40 to 473 K. At low temperatures, the temperature dependence is very strong, but as the temperature is raised above room temperature, the dependence becomes very weak. Moreover, a secondary peak becomes evident below 100 K. It is suggested here that this change in behavior is due to an anti-phase tilting of the oxygen octahedra coupled with some ordering of the Pb displacements. The temperature dependence of the 1/2(hk2l) positions, e.g. 1/2(015) and 1/2(017), were carefully studied through the transition down to 40 K, as well. Peaks at these positions appear at low temperatures due to the in-phase tilting of the BO6 octahedra, but its long-range order is never established. These results imply that both ferroelectric and anti-ferroelectric fluctuations are present in the structure and are evidence of competing interactions in PMN. Along with the quenched disorder due to the B-site randomness, these interactions induce orientational frustration of electric dipoles (Pb-O) in the structure and lead to the observed dielectric behavior. Thus, PMN possesses the underlying physical characteristics of a dipole glass system. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Chen, H (reprint author), Univ Illinois, Dept Mat Sci & Engn, 1304 W Green St, Urbana, IL 61801 USA. NR 42 TC 18 Z9 18 U1 0 U2 1 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 FEB PY 2000 VL 61 IS 2 BP 221 EP 227 DI 10.1016/S0022-3697(99)00285-1 PG 7 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 263VY UT WOS:000084147000013 ER PT J AU Louca, D Roder, H Sarrao, JL Dimitrov, DA Wills, JM Swart, PJ Bishop, AR AF Louca, D Roder, H Sarrao, JL Dimitrov, DA Wills, JM Swart, PJ Bishop, AR TI The local atomic structure and phonons in Ba0.5Sr0.5TiO3 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Williamsburg Workshop on Ferroelectrics 99 CY JAN 31-FEB 03, 1999 CL WILLIAMSBURG, VIRGINIA SP Off Naval Res DE local disorder; phase transitions ID BATIO3; PHASE AB The study of the local atomic structure of the solid solution of Ba0.5Sr0.5TiO3 (BST) has shown that its microscopic properties are quite distinct from those of the end members of the series, BaTiO3 (BTO) and SrTiO3 (STO). In contrast to BTO and STO, the BST structure changes as a function of temperature at short length scales, but not on average. However, from the extraction of phonon dynamics from the diffraction measurement, the presence of a soft mode behavior similar to the soft mode observed in BTO is suggested. This indicates that lattice instabilities are driven by mechanisms that are similar to those observed in the ferroelectric transition of BTO and the structural transition of STO. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Louca, D (reprint author), Univ Virginia, Dept Phys, Charlottesville, VA 22903 USA. NR 13 TC 3 Z9 4 U1 0 U2 3 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 FEB PY 2000 VL 61 IS 2 BP 239 EP 242 DI 10.1016/S0022-3697(99)00287-5 PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 263VY UT WOS:000084147000015 ER PT J AU Yang, TJ Gopalan, V Swart, P Mohideen, U AF Yang, TJ Gopalan, V Swart, P Mohideen, U TI Experimental study of internal fields and movement of single ferroelectric domain walls SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Williamsburg Workshop on Ferroelectrics 99 CY JAN 31-FEB 03, 1999 CL WILLIAMSBURG, VIRGINIA SP Off Naval Res DE scanning force microscopy ID ATOMIC-FORCE MICROSCOPY; NANOSCALE VISUALIZATION; LITAO3; CRYSTALS; ORIGIN AB We have made a direct and submicron scale measurement of the strain, internal electric field of single 180 degrees domain walls in ferroelectric LiTaO3 using a collection mode Near-Field Scanning Optical Microscope. We unambiguously identify single domain walls by simultaneously recording nanometer scale topographic and optical images. The birefringence at the domain wall is used in the optical imaging. From the internal field structure we estimate the interface energy. We have also studied the pinning and movement of a single 180 degrees domain wall under an uniform applied electric field. The domain wall was observed to curve between the pinning defects with a radius of curvature uniquely given by the material parameters and the applied electric field. The change in birefringence with applied field is related to the second order electro-optic and piezo-optic coefficients and is used to infer the orientation of the internal field. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Mohideen, U (reprint author), Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 27 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD FEB PY 2000 VL 61 IS 2 BP 275 EP 282 DI 10.1016/S0022-3697(99)00293-0 PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 263VY UT WOS:000084147000021 ER PT J AU Fellner, C Newman, J AF Fellner, C Newman, J TI High-power batteries for use in hybrid vehicles SO JOURNAL OF POWER SOURCES LA English DT Article DE hybrid; vehicle; battery ID ROCKING-CHAIR; LITHIUM AB The idea of hybrid vehicles is not a recent development; Its early as the 1960s, several have companies attempted to develop bipolarlead/acid batteries for hybrid-electric vehicles [J.L. Arias, J.J Rowlett, E.D. Drake, Journal of Power Sources, 40 (1993) 63-73.]. Hybrid vehicles have the potential to increase fuel economy by using a primary engine operating at a constant power to supply average power requirements and a surge power unit for peak power demands and to recover braking energy. To date, no detailed system optimization analysis has been performed for hybrid vehicles. This study combines a simplified version of the lithium-ion battery model developed by Doyle [C.M. Doyle, Design and simulation of lithium rechargeable batteries, Dissertation, Fall, 1995.] with a vehicle model that determines battery-power requirements for a given driving cycle. Batteries are designed for either the highest vehicle mileage or minimal acceptable battery dimensions. Hybrid vehicles have the potential to more than double mileage as compared to conventional vehicles, and have a limited electric vehicle range. The battery goals of the Partnership for a New Generation of Vehicles (PNGV) are investigated and often found to be differing with actual requirements. Specifically, PNGV overstates power and especially energy requirements for load-leveling devices and calls for unnecessary demands on the development of alternate technologies. The role of the driving cycle was investigated and found to be relatively unimportant as long as it contains several essential features. The important parameters in the driving cycle are the time of discharge and the maximum current (or power) level. This study suggests that a combination of both a vehicle model and a battery model is required to determine the complex interaction between hybrid-vehicle weight and battery power. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Newman, J (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Newman, John/B-8650-2008 OI Newman, John/0000-0002-9267-4525 NR 8 TC 50 Z9 55 U1 1 U2 20 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD FEB PY 2000 VL 85 IS 2 BP 229 EP 236 DI 10.1016/S0378-7753(99)00344-4 PG 8 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 290BB UT WOS:000085655500007 ER PT J AU Jiang, W Tran, T Song, X Kinoshita, K AF Jiang, W Tran, T Song, X Kinoshita, K TI Thermal and electrochemical studies of carbons for Li-ion batteries 1. Thermal analysis of petroleum and pitch cokes SO JOURNAL OF POWER SOURCES LA English DT Article DE thermal analysis; coke; oxidation; Li-ion batteries ID GRAPHITE; SYSTEM AB Thermal analyses involving simultaneous thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study the air oxidation of petroleum (fluid and needle cokes) and coal-tar pitch cokes. The intent of this study is to understand the relationship between the structure of carbonaceous materials and their thermal oxidation behavior in air (Part 1). A correlation between the thermal oxidative properties of cokes and their electrochemical Li-intercalation performance is discussed in the following paper (Part 2). The carbon samples were heat-treated at temperatures up to 2800 degrees C, and three thermal parameters were determined - ignition temperature (T-i), temperature maximum (T-m) in the DTA. curves, and the temperature at which 15% carbon weight loss was attained (T-15). The measurements showed trends that are consistent with prior reports that the active sites on the surface and not the total surface area (TSA) are responsible for the thermal behavior of the carbons. Because of the difference in the graphitizability of petroleum and pitch cokes that was obtained by heat treatment, variations in the thermal parameters were observed. Needle cokes are the most easily graphitized and this is reflected in the higher values of the thermal parameters compared to the fluid and pitch cokes. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Kinoshita, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, 90-1142, Berkeley, CA 94720 USA. NR 20 TC 18 Z9 18 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD FEB PY 2000 VL 85 IS 2 BP 261 EP 268 DI 10.1016/S0378-7753(99)00342-0 PG 8 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 290BB UT WOS:000085655500011 ER PT J AU Tran, T Yebka, B Song, X Nazri, G Kinoshita, K Curtis, D AF Tran, T Yebka, B Song, X Nazri, G Kinoshita, K Curtis, D TI Thermal and electrochemical studies of carbons for Li-ion batteries 2. Correlation of active sites and irreversible capacity loss SO JOURNAL OF POWER SOURCES LA English DT Article DE irreversible capacity; carbon structure; Li-ion batteries ID GRAPHITE INTERCALATION COMPOUNDS; LITHIUM INTERCALATION; RECHARGEABLE BATTERIES; CARBONACEOUS MATERIALS; DISORDERED CARBONS; ANODE; INSERTION; ELECTROLYTE; BEHAVIOR; CELLS AB Thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) involving air oxidation of fluid coke, coal-tar pitch delayed coke and needle coke suggested that active sites are I,resent which can be correlated to the crystallographic parameters, L-a and L-c, and the d(002) spacing. This finding was extended to determine the relationship between active sites on carbon and their role in catalyzing electrolyte decomposition leading to irreversible capacity loss (ICL) in Li-ion batteries. Electrochemical data from this study with graphitizable carbons and from published Literature were analyzed to determine the relationship between the physical properties of carbon and the ICL during the first charge/discharge cycle. Based on this analysis, we conclude that the active surface area, and not the total BET surface area, has an influence on the ICL of carbo,ns for Li-ion batteries. This conclusion suggests that the carbon surface structure plays a significant role in catalyzing electrolyte decomposition. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RP Kinoshita, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 37 TC 22 Z9 22 U1 2 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD FEB PY 2000 VL 85 IS 2 BP 269 EP 278 DI 10.1016/S0378-7753(99)00343-2 PG 10 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 290BB UT WOS:000085655500012 ER PT J AU Althouse, PE AF Althouse, PE TI Radiological background levels found in glass fiber filters used for low-level environmental surveillance air sampling SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB Environmental surveillance monitoring of low-level radioactive particles in air requires a thorough understanding of low-level techniques and air sample collection media. High-volume air sampling for radioactive particles around Lawrence Livermore National Laboratory (LLNL) currently employs glass-fiber filters that are analyzed for gross alpha and gross beta activity and for specific isotopes. This study was conducted to determine the activities of radionuclides contained in blank glass-fiber filters. Data from this study provided a partial explanation of differences between current reported concentrations of radionuclides in air and those reported historically when cellulose filters were used in the LLNL monitoring effort. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Althouse, PE (reprint author), Univ Calif Lawrence Livermore Natl Lab, UCRL-JC-131844, Livermore, CA 94551 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 289 EP 293 DI 10.1023/A:1016068401980 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200003 ER PT J AU Kraig, DH Conrad, RC AF Kraig, DH Conrad, RC TI Air monitoring data reveal previously unknown contamination at radioactive waste disposal area, Los Alamos National Laboratory SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB Air monitoring at Area G, the low-level radioactive waste disposal area at Los Alamos National Laboratory, revealed increased air concentrations of (PU)-P-239 and Am-241 at one location along the north boundary. This air monitoring location is a couple of meters north of a dirt road used to access the easternmost part of Area G. Air concentrations of (PU)-P-238 were essentially unaffected, which was puzzling because both Pu-238 and Pu-239 are present in the local. slightly contaminated soils. Air concentrations of these radionuclides increased about a factor of ten in early 1995 and remained at those levels until the first quarter of 1996. During the spring of 1996 air concentrations again increased by a factor of about ten. No other radionuclides were elevated, and no other Area G stations showed elevations of these radionuclides. After several formal meetings did not provide an adequate explanation for the elevations, a gamma-survey was performed and showed a small area of significant contamination just south of the monitor location. We found that in February 1995, a trench for a water line had been dug within a meter or so of the air stations. Then, during early 1996, the dirt road was rerouted such that its new path was directly over the unknown contamination. It appears that the trenching brought contaminated material to the surface and caused the first rise in air concentrations and then the rerouting of the road over the contamination caused the second rise. during 1996. We also found that during 1976 and 1977 contaminated soils from the clean-up of an old processing facility had been spread over the filled pits in the vicinity of the air monitors. These soils, which were probably the source of the air contamination, were very low in Pu-238 which explains why we saw very little Pu-238 in the increased air concentrations. A layer of gravel and sand as spread over the contaminated area. Although air concentrations of Pu-239 and Am-241 dropped considerably, they have not returned to pre-1995 levels. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kraig, DH (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,Mail Stop J978, Los Alamos, NM 87545 USA. NR 5 TC 1 Z9 1 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 353 EP 359 DI 10.1023/A:1016049308340 PG 7 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200012 ER PT J AU Seymour, RS Richardson, B Morichi, M Bliss, M Craig, RA Sunberg, DS AF Seymour, RS Richardson, B Morichi, M Bliss, M Craig, RA Sunberg, DS TI Scintillating-glass-fiber neutron sensors, their application and performance for plutonium detection and monitoring SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB Most neutron detection sensors presently employ He-3 gas-filled detectors. Despite their excellent performance and widespread use, there are significant limitations to this technology. A significant alternative neutron sensor utilizing neutron-active material incorporated into a glass scintillator is presented that offers novel commercial sensors not possible or practical with gas tube technology. The scintillating optical fiber permits sensors with a multitude of sizes ranging from devices of a single fiber of 150 mum to sensors with tens of thousands of fibers with areas as large as 5 m(2) depending on the neutron flux to be measured. A second significant advantage is the use of high-speed electronics that allow a greater dynamic range, not possible with gas detectors. These sensors are flexible, conformable and less sensitive to vibration that optimizes the source-to-detector geometry and provides robust performance in field applications. The glass-fibers are sensitive to both gamma-rays and neutrons. However, the coincidence electronics are optimized for neutron to gamma-ray discrimination allowing very sensitive measurements with a low false-alarm rate. Applications include SNM surveillance, material control and accountability (MC&A), safeguard inspections, Pu health physics/bioassay and environmental characterization. C1 Oxford Instruments Inc, Nucl Measurements Grp, Oak Ridge, TN 37830 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Seymour, RS (reprint author), Oxford Instruments Inc, Nucl Measurements Grp, 601 Oak Ridge Turnpike, Oak Ridge, TN 37830 USA. RI Bliss, Mary/G-2240-2012 OI Bliss, Mary/0000-0002-7565-4813 NR 7 TC 6 Z9 6 U1 1 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 387 EP 388 DI 10.1023/A:1016009726996 PG 2 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200017 ER PT J AU Hamilton, TF Robison, WL Kehl, S Stoker, AC Conrado, CL AF Hamilton, TF Robison, WL Kehl, S Stoker, AC Conrado, CL TI The Marshall Islands radioassay quality assurance program: An overview SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB The Lawrence Livermore National Laboratory has developed an extensive quality assurance program to provide high quality data and assessments in support of the Marshall Islands Dose Assessment and Radioecology Program. Our quality assurance objectives begin with the premise of providing integrated and cost-effective program support (to meet wide-ranging programmatic needs, scientific peer review, and build public confidence) and continue through from design and implementation of large-scale field programs, sampling and sample preparation, radiometric and chemical analyses, documentation of quality assurance/quality control practices, exposure assessments, and dose/risk assessments until publication. The basic structure of our radioassay quality assurance/quality control program can be divided into four essential elements: (1) sample and data integrity control, (2) instrument validation and calibration, (3) method performance testing, validation, development and documentation, and (4) periodic peer review and on-site assessments. While our quality assurance objectives are tailored towards a single research program and the evaluation of major exposure pathways/critical radionuclides pertinent to the Marshall Islands, we have attempted to develop quality assurance practices that are consistent with proposed criteria designed for laboratory accreditation. C1 Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessments Div, Livermore, CA 94550 USA. RP Hamilton, TF (reprint author), Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessments Div, POB 808,L-453, Livermore, CA 94550 USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 415 EP 422 DI 10.1023/A:1016022029721 PG 8 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200022 ER PT J AU Robison, WL Conrado, CL Hamilton, TF Stoker, AC AF Robison, WL Conrado, CL Hamilton, TF Stoker, AC TI The effect of carbonate soil on transport and dose estimates for long-lived radionuclides at a US Pacific Test Site SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB The United States conducted a series of nuclear tests from 1946 to 1958 at Bikini, a coral atoll, in the Marshall Islands (MI). The aquatic and terrestrial environments of the atoll are still contaminated with several long-lived radionuclides that were generated during testing. The four major radionuclides found in terrestrial plants and soils are cesium-137, strontium-90, plutonium-239+240 and americium-241. Cesium-137 in the coral soils is more available for uptake by plants than Cs-137 associated with continental soils of North America or Europe. Soil-to-plant Cs-137 median concentration ratios (CR) (kBq.kg(-1) dry weight plant/kBq.kg(-1) dry weight soil) for tropical fruits and vegetables range between 0.8 and 36, much larger than the range of 0.005 to 0.5 reported for vegetation in temperate zones. Conversely, Sr-90 median CRs range from 0.006 to 1.0 at the atoll versus a range from 0.02 to 3.0 for continental silica-based soils. Thus, the relative uptake of Cs-137 and Sr-90 by plants in carbonate soils is reversed from that observed in silica-based soils. The CRs for Pu239+240 and Am-241 are very similar to those observed in continental soils. Values range from 10(-6) to 10(-4) for both Pu239+240 and Am-241. No significant difference is observed between the two in coral soil. The uptake of Cs-137 by plants is enhanced because of the absence of mineral binding sites and the low concentration of potassium in the coral soil. Cesium-137 is bound to the organic fraction of the soil, whereas Sr-90, Pu239+240 and Am-241 are primarily bound to soil particles. Assessment of plant uptake for Cs-137 and Sr-90 into locally grown food crops was a major contributing factor in: (1) reliably predicting the radiological dose for returning residents and (2) developing a strategy to limit the availability and uptake of Cs-137 into locally grown food crops. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Robison, WL (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 E Ave,L-286, Livermore, CA 94550 USA. NR 18 TC 5 Z9 5 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 459 EP 465 DI 10.1023/A:1016090517426 PG 7 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200027 ER PT J AU Vanmiddlesworth, L Handle, J Johns, P AF Vanmiddlesworth, L Handle, J Johns, P TI Iodine-129 in thyroid glands: A sensitive biological marker of fission product exposure SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc ID I-129; ACCIDENT AB Iodine-129 may have no radiation hazard but it is a useful marker. Animal thyroids concentrate the isotope to 4 orders of magnitude greater than the intake. This results in a potential biological and physical indicator of radioiodine contamination. Since 1943, I-129/I-127 ratio in animal thyroids from the Northern Hemisphere has increased 2 to 5 orders of magnitude. Since 1985, thyroids of deer living near a nuclear reprocessing facility have contained I-129, which are 3 to 7 orders of magnitude greater than pre-nuclear levels. Limited measurements of I-129 in thyroids from the Southern Hemisphere have shown little increase. An appendix is presented to show that I-129 may be helpful to evaluate past radiation hazard from fission products. C1 Univ Tennessee, Memphis, TN 38163 USA. Univ Hannover, Strahlenschutz & Radiooekol, Hannover, Germany. Univ Georgia, Savannah River Ecol Lab, Aiken, SC USA. RP Vanmiddlesworth, L (reprint author), Univ Tennessee, Memphis, TN 38163 USA. NR 14 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 467 EP 472 DI 10.1023/A:1016042618335 PG 6 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200028 ER PT J AU Ebaid, YY El-Tahawy, MS El-Lakany, AA Garcia, SR Brooks, GH AF Ebaid, YY El-Tahawy, MS El-Lakany, AA Garcia, SR Brooks, GH TI Environmental radioactivity measurements of Egyptian soils SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc ID URANIUM AB Soil and vegetation samples from 33 sites within the northwestern area of the River Nile delta in Egypt have been analyzed for natural and manmade radioactivity. Gamma-ray spectrometric measurements were performed where Bi-214 and Pb-214 were used for U-238-series determinations, while Tl-208 and Ac-228 were used for Th-232-series determinations. In addition, alpha-spectrometric measurements were also performed for the determination of different isotopes of uranium and plutonium. Other parameters examined included the determination of radium equivalent activities and relationship between the gamma-radiation values and subsequent dose level determinations and the soil types. C1 Natl Ctr Nucl Safety & Radiat Control, Cairo, Egypt. Cairo Univ, Fac Sci, Biophys Dept, Giza, Egypt. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ebaid, YY (reprint author), Natl Ctr Nucl Safety & Radiat Control, POB 7551, Cairo, Egypt. NR 14 TC 16 Z9 16 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 543 EP 550 DI 10.1023/A:1016075508765 PG 8 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200039 ER PT J AU Hooda, B Scott, GL Jones, SB AF Hooda, B Scott, GL Jones, SB TI Characterization of radioactive hazardous waste SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Conference on Low-Level Measurements of Actinides and Long-Lived Radionuclides in Biological and Environmental Samples CY SEP 21-25, 1998 CL SALT LAKE CITY, UTAH SP US DOE, Carlsbad Area Off, Oxford Instruments Inc, Envirocare, Westinghouse WIPP, Eichrom Ind Inc AB The characterization of radioactive hazardous waste, also known as transuranic "mixed waste" has to be completed before it can be classified for proper treatment (incinerator, mechanical compaction or thermal treatment), packing, and transport. The characterization of the TRU mixed waste is not only complex process but rather an expensive undertaking. The process knowledge is the basic foundation of characterization. It is the documented knowledge of processes and materials that generated the waste. The transuranic waste Quality Assurance Program Plan (QAPP) defines the Data Quality Objectives (DQO's) and provides the scope of analytical parameters and methods required to accurately characterize the radioactive mixed waste. Based on the historical data and process knowledge a sampling and analysis plan can be developed to characterize the radioactive hazardous waste. Based on the characterization, an assessment of the regulatory status can be made before the waste could be accepted for disposal at the WIPP facility. The Waste Acceptance Criteria (WAC) developed by WIPP defines the parameters for receiving and final disposal of the TRU waste. The sets of criteria, such as: heat generated, fissile gram equivalent (FGE), plutonium-equivalent (PE) curies, and specifications of a dose rate have to be met before the waste is accepted For deep geological disposal. The characterization of radioactive waste becomes even more complex due to the presence of iron base metals/alloys, aluminum base metals/alloys, organic, chelating agents that are mixed with plastic, rubber, cellulose, soils and cement. Some of the modern characterization technologies that are under development and currently used for TRU mixed wastes are: nondestructive examination, nondestructive assay, headspace gas analysis, and drum coring for Resources Conservation Recovery Act (RCRA) sampling. C1 Westinghouse, WIPP, Carlsbad, NM 88221 USA. US DOE, CAO, Carlsbad, NM 88221 USA. RP Hooda, B (reprint author), Westinghouse, WIPP, POB 2078, Carlsbad, NM 88221 USA. NR 4 TC 0 Z9 0 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD FEB PY 2000 VL 243 IS 2 BP 551 EP 553 DI 10.1023/A:1016027625604 PG 3 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375FE UT WOS:000165388200040 ER PT J AU Williford, RE Armstrong, TR Gale, JD AF Williford, RE Armstrong, TR Gale, JD TI Chemical and thermal expansion of calcium-doped lanthanum chromite SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE lanthanum chromite; calcium doping; coefficient of chemical expansion; coefficient of thermal expansion; atomistic models ID PEROVSKITE-TYPE OXIDES; DEFECT CHEMISTRY; SIMULATION; DERIVATION; STABILITY; TRANSPORT AB Atomistic free-energy minimization techniques were used to simulate three simultaneous volumetric shrinkage/expansion phenomena in calcium-doped lanthanum chromite solid oxide fuel cell (SOFC) interconnect materials. Four sets of interatomic potentials were developed and tested over the temperature range 0-1273 K. The predicted unit-cell volumes, elastic properties, volumetric shrinkage due to A-site doping of the ABO, perovskite (La1-xCax)CrO3, defect-induced volumetric expansion due to reducing atmospheres, and thermal expansion were in reasonable agreement with experiment, though not all concurrently with a single set of potentials. Potentials based either on simple oxides or on partial charge models appeared to give the best overall predictions. Additional experimental data are needed to improve the potentials. (C) 2000 Academic Press. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ London Imperial Coll Sci Technol & Med, Dept Chem, S Kensington SW7 2AY, England. RP Williford, RE (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. RI Gale, Julian/B-7987-2009 OI Gale, Julian/0000-0001-9587-9457 NR 34 TC 11 Z9 13 U1 1 U2 5 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 FEB 1 PY 2000 VL 149 IS 2 BP 320 EP 326 DI 10.1006/jssc.1999.8533 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 281NQ UT WOS:000085167700015 ER PT J AU Iversen, BB Palmqvist, AEC Cox, DE Nolas, GS Stucky, GD Blake, NP Metiu, H AF Iversen, BB Palmqvist, AEC Cox, DE Nolas, GS Stucky, GD Blake, NP Metiu, H TI Why are clathrates good candidates for thermoelectric materials? SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID MAXIMUM-ENTROPY METHOD; ELECTRON-DENSITY-DISTRIBUTION; GE AB Clathrates are periodic solids in which tetrahedrally coordinated atoms-form cages that surround a metal atom. We examine Slack's suggestion that the metal atoms scatter phonons but not electrons, thus lowering the thermal but not the electric conductivity. If this is true, as transport measurements indicate, these compounds are promising thermoelectric materials, (C) 2000 Academic Press. C1 Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. Marlow Ind Inc, Div Res & Dev, Dallas, TX 75238 USA. Aarhus Univ, Dept Chem, DK-8000 Aarhus C, Denmark. RP Iversen, BB (reprint author), Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. RI Palmqvist, Anders/C-4005-2011; OI Palmqvist, Anders/0000-0002-7579-3936 NR 19 TC 80 Z9 81 U1 2 U2 17 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 FEB 1 PY 2000 VL 149 IS 2 BP 455 EP 458 DI 10.1006/jssc.1999.8534 PG 4 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 281NQ UT WOS:000085167700035 ER PT J AU Nguyen-Trung, C Palmer, DA Begun, GM Peiffert, C Mesmer, RE AF Nguyen-Trung, C Palmer, DA Begun, GM Peiffert, C Mesmer, RE TI Aqueous uranyl complexes 1. Raman spectroscopic study of the hydrolysis of uranyl(VI) in solutions of trifluoromethanesulfonic acid and/or tetramethylammonium hydroxide at 25 degrees C and 0.1 MPa SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE hydrolysis; uranyl(VI); Raman, thermodynamics; aqueous; structure ID DIOXOURANIUM(VI) ION; EXCITATION PROFILE; NITRATE AB Raman spectra have been used to identify and characterize aqueous hydroxouranyl (VI) complexes from 0.0038 to 0.647M at pH from 0.24 to 14.96 adjusted with either HCF3SO3 and/or (CH3)(4)NOH under ambient conditions. In acidic media (0.24 less than or equal to pH less than or equal to 5.63, the existence of four species UO22+,(UO2)(2)(OH)(3+), (UO2)(2)(OH)(2)(2+), and (UO2)(3)(OH)(5)(+) was confirmed. At high uranium concentrations (Sigma U greater than or equal to 0.1M) and in strongly acidic solutions (pH less than or equal to 1.94), one additional weak band was observed at 883+/-1 cm(-1). This band was assumed to represent the species UO22+ with a reduced hydration number. In neutral and basic solutions (5.63 less than or equal to pH less than or equal to 14.96), five complexes were postulated: (UO2)(3)(OH)(7)(-), (UO2)(3)(OH)(8)(2-), (UO2)(3)(OH)(10)(4-), (UO2)(3)(OH)(11)(5-), and UO2(OH)(4)(2-), based on the assigned symmetrical stretching frequencies of the UO2 group in each complex. (UO2)3(OH)7- is the dominant species over most of the pH range (4.53-12.78). The stability ranges of the other trinuclear species are: (UO2)(3)(OH)(8)(2-) (10.97 less than or equal to pH less than or equal to 13.83), (UO2)(3)(OH)(10)(4-) (10.97 less than or equal to pH less than or equal to 13.85), and (UO2)(3)(OH)(11)(5-) (12.53 less than or equal to pH less than or equal to 14.10), which were identified for the first time. Finally the monomeric uranate anion UO2(OH)(4)(2-) dominates in highly basic solution (12.48 less than or equal to pH less than or equal to 14.96). The linear correlation between the symmetrical vibrational frequency nu(1) of the linear O = U = O entity and the average number (n) over bar of hydroxide ligands coordinated to each uranium atom in a given species has been reaffirmed and expanded: nu(1) (cm(-1)) = -22x (n) over bar + 870 The nu(1) correlation was also used to predict the vibration frequencies of the undetected monomers UO2(OH)(+), UO2(OH)(2)(o), UO2(OH)(3)(-) at 848+/-2, 826+/-2, and 804+/-2 cm(-1), respectively. Characteristic band areas for each uranyl hydrolyzed species were determined by Raman spectra decomposition and their hydrolysis quotients log Q, were calculated. Structures of the four triuranyl species ate proposed. C1 CREGU, F-54501 Vandoeuvre Nancy, France. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Nguyen-Trung, C (reprint author), CREGU, BP 23, F-54501 Vandoeuvre Nancy, France. NR 50 TC 63 Z9 65 U1 3 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 FEB PY 2000 VL 29 IS 2 BP 101 EP 129 DI 10.1023/A:1005197030188 PG 29 WC Chemistry, Physical SC Chemistry GA 287ZP UT WOS:000085537600001 ER PT J AU Nadiga, BT AF Nadiga, BT TI Scaling properties of an inviscid mean-motion fluid model SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE mean-motion fluid model; second-grade fluids; subgrid model; nonlinear dispersion; two-constraint statistical theory ID FLOWS AB An inviscid two-dimensional fluid model with nonlinear dispersion that arises simultaneously in coarse-grained descriptions of the dynamics of the Euler equation and in the description of non-Newtonian fluids of second grade is consider ed. The scaling of the equilibrium states of this model for conserved energy and enstrophy retains the corresponding scaling For the Euler equations on the large scales and at the same time greatly deemphasizes the importance of small scales. This is the first clear , demonstration of the beneficial effect of nonlinear dispersion in the model, and should highlight its utility as a subgrid model ill molt: realistic situations. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nadiga, BT (reprint author), Univ Calif Los Alamos Natl Lab, MS-B296, Los Alamos, NM 87545 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD FEB PY 2000 VL 98 IS 3-4 BP 935 EP 948 DI 10.1023/A:1018644029435 PG 14 WC Physics, Mathematical SC Physics GA 298PH UT WOS:000086148000019 ER PT J AU Reifman, J Feldman, EE Wei, TYC Glickert, RW AF Reifman, J Feldman, EE Wei, TYC Glickert, RW TI An intelligent emissions controller for fuel lean gas reburn in coal-fired power plants SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID NEURAL NETWORKS AB The application of artificial intelligence techniques for performance optimization of the fuel lean gas reburn (FLGR) system is investigated. A multilayer, feedforward artificial neural network is applied to model static nonlinear relationships between the distribution of injected natural gas into the upper region of the furnace of a coal-fired boiler and the corresponding oxides of nitrogen (NOx) emissions exiting the furnace. Based on this model, optimal distributions of injected gas are determined such that the largest NOx reduction is achieved for each value of total injected gas. This optimization is accomplished through the development of a new optimization method based on neural networks. This new optimal control algorithm, which can be used as an alternative generic tool for solving multidimensional nonlinear constrained optimization problems, is described and its results are successfully validated against an off-the-shelf tool for solving mathematical programming problems. Encouraging results obtained using plant data from one of Commonwealth Edison's coal-fired electric power plants demonstrate the feasibility of the overall approach. Preliminary results show that the use of this intelligent controller will also enable the determination of the most east-effective operating conditions of the FLGR system by considering, along with the optimal distribution of the injected gas, the cost differential between natural gas and coal and the open-market price of NOx emission credits. Further study, however, is necessary, including the construction of a more comprehensive database, needed to develop high-fidelity process models and to add carbon monoxide (CO) emissions to the model of the gas reburn system. C1 Argonne Natl Lab, Reactor Anal Div, Engn Res Program, Argonne, IL 60439 USA. Energy Syst Associates, Pittsburgh, PA USA. Argonne Natl Lab, Reactor Engn Div, Engn Res Program, Argonne, IL 60439 USA. RP Reifman, J (reprint author), Argonne Natl Lab, Reactor Anal Div, Engn Res Program, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 18 TC 3 Z9 3 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 FEB PY 2000 VL 50 IS 2 BP 240 EP 251 PG 12 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 280WG UT WOS:000085126300011 PM 10680354 ER PT J AU Cadle, SH Gorse, RA Bailey, BK Lawson, DR AF Cadle, SH Gorse, RA Bailey, BK Lawson, DR TI Real-world vehicle emissions: A summary of the ninth coordinating research council on-road vehicle emissions workshop SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article AB In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contribution of mobile sources to emission inventories, efforts to evaluate and improve mobile source emission models, progress of vehicle inspection/maintenance programs, and topics for future research. While significant progress has been made in understanding in-use vehicle emissions, further improvements are necessary. Moreover, the impact of current and future changes in emission control technologies and control programs will have to be monitored for effectiveness and incorporated into the emission factor models. C1 GM Corp, R&D Ctr, Warren, MI USA. Ford Motor Co, Allen Park, MI USA. Coordinating Res Council, Atlanta, GA USA. RP Lawson, DR (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 1 TC 3 Z9 3 U1 0 U2 3 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 FEB PY 2000 VL 50 IS 2 BP 278 EP 291 PG 14 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 280WG UT WOS:000085126300015 PM 10680358 ER PT J AU Huang, JY Yasuda, H Mori, H AF Huang, JY Yasuda, H Mori, H TI HRTEM and EELS studies on the amorphization of hexagonal boron nitride induced by ball milling SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID DIAMOND-LIKE CARBON; CUBIC BN; PRESSURE; TRANSITION; PHASES; SILICON AB We present a new approach, namely ball milling, to synthesize amorphous boron nitride (a-BN), The amorphization kinetics are revealed by X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS), HRTEM investigations indicate that, in the early stage of milling, the thick sp(2) layers are sliced into many thinner sheets because of cleavage;along the basal planes, In the intermediate stage of milling, deformation is accommodated primarily by simultaneous shearing along the basal planes. As a result of sustained shearing, a number of defects, such as stacking faults, (0002) [11 (2) over bar 0] twinning, simultaneous shearing of lattice planes, and half Frank loops with Burgers vectors of 1/2[0001], are introduced in the hexagonal BN (h-BN) grains. Simultaneous shearing also causes significant change in the lattice symmetry of most grains. In the final stage of milling, the fiberlike tightly bonded sp2 sheets are broken and refined further, until a nanocrystalline and amorphous mixture is formed. XRD of the sample mined for 180 b exhibits an amorphous halo pattern; nevertheless, HRTEM demonstrates that the end product is essentially a nanocrystalline and amorphous mixture. The grain sizes of the nanocrystals are <3 nm, and their stacking is turbostratic. EELS investigations of the a-BN indicate that bonding is :primarily sp2, but a small fraction of sp(3) a-BN is also found, which is assumed to be the nuclei of the cubic phase (c-BN) in the high-pressure and high-temperature experiments and thus facilitates the hexagonal to cubic transition, The present a-BN fabrication method can provide an effective way to facilitate the synthesis of sintered bulk c-BN materials. C1 Osaka Univ, Res Ctr Ultrahigh Voltage Electron Microscopy, Suita, Osaka 565, Japan. Chinese Acad Sci, Inst Met Res, Atom Imaging Solids Lab, Shenyang 110015, Peoples R China. RP Huang, JY (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI Huang, Jianyu/C-5183-2008 NR 35 TC 54 Z9 54 U1 7 U2 48 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 FEB PY 2000 VL 83 IS 2 BP 403 EP 409 PG 7 WC Materials Science, Ceramics SC Materials Science GA 291XJ UT WOS:000085764600023 ER PT J AU Superko, HR Krauss, RM AF Superko, HR Krauss, RM TI Garlic powder, effect on plasma lipids, postprandial lipemia, low-density lipoprotein particle size,high-density lipoprotein subclass distribution and lipoprotein(a) SO JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY LA English DT Article ID CORONARY-ARTERY DISEASE; HYPERCHOLESTEROLEMIC MEN; ANGIOGRAPHIC BENEFIT; CHOLESTEROL; ATHEROSCLEROSIS; THERAPY; HETEROGENEITY; PATTERNS; DIET; RISK AB OBJECTIVES To test the hypothesis that a garlic supplement alters plasma lipoproteins, postprandial lipemia, low-density lipoprotein (LDL) size and high-density lipoprotein (HDL) subclass distribution differently in 50 moderately hypercholesterolemic subjects classified as LDL subclass pattern A or B. BACKGROUND Garlic has been variably reported to reduce dr not affect plasma cholesterol values. Low-density lipoprotein pattern B is a common inherited disorder of lipoprotein metabolism that has been shown to have a significantly greater response to several lipid lowering treatments including low fat diet when Compared with LDL pattern A individuals. METHODS A double blind, randomized, placebo controlled trial in an outpatient lipid research clinic was performed and included fifty moderately hypercholesterolemic subjects (mean LDL cholesterol = 166 +/- 22 mg/dl) classified as LDL subclass pattern A (predominantly large LDL, n = 22) or B (predominantly small LDL, n = 28). Following a two-month stabilization period, subjects were randomly assigned to a placebo or 300 mg three times a day of a standardized garlic tablet for three months. RESULTS For all subjects, LDL pattern A and B subjects combined, garlic treatment for three months resulted in no significant change in total cholesterol, LDL cholesterol, HDL cholesterol, HDL subclass distribution, postprandial triglycerides, apolipoprotein B, lipoprotein (a) (Lp[a]), LDL peak particle diameter or LDL subclass distribution. There was no significant difference in response for the same parameters among subjects classified as LDL pattern A or B with the exception of significantly greater (p = 0.01) reduction in mean peak particle diameter in pattern A subjects treated with either garlic or placebo. There was no significant change in LDL subclass distribution. CONCLUSIONS This investigation confirms that garlic therapy has no effect on major plasma lipoproteins and further, that it has no impact on HDL subclasses, Lp(a), apolipoprotein B, postprandial triglycerides or LDL subclass distribution. Garlic may have a greater effect on LDL particle diameter in LDL pattern A compared with-pattern B subjects. This difference was not reflected in other plasma lipid measurements. (J Am Coll Cardiol 2000;35:321-6) (C) 2000 by the American College of Cardiology. C1 Berkeley Heart Lab, Cholesterol Genet & Heart Dis Inst, San Mateo, CA 94402 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Mol & nucl Med, Div Life Sci, Berkeley, CA USA. RP Superko, HR (reprint author), Berkeley Heart Lab, Cholesterol Genet & Heart Dis Inst, 1875 S Grant St,Suite 700, San Mateo, CA 94402 USA. OI Superko, H. Robert/0000-0002-3542-0393 FU NHLBI NIH HHS [HL 18574] NR 34 TC 50 Z9 53 U1 1 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0735-1097 J9 J AM COLL CARDIOL JI J. Am. Coll. Cardiol. PD FEB PY 2000 VL 35 IS 2 BP 321 EP 326 DI 10.1016/S0735-1097(99)90541-7 PG 6 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 282FK UT WOS:000085207100009 PM 10676676 ER PT J AU Schaaff, TG Stephenson, JL McLuckey, SA AF Schaaff, TG Stephenson, JL McLuckey, SA TI Gas phase H/D exchange kinetics: DI versus D2O SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID QUADRUPOLE ION-TRAP; PROTON-TRANSFER REACTIONS; CYTOCHROME-C IONS; MASS-SPECTROMETRY; PEPTIDE IONS; HYDROGEN/DEUTERIUM EXCHANGE; DEUTERIUM-EXCHANGE; MOLECULE REACTIONS; HIGH-RESOLUTION; ACID-RESIDUES AB The gas phase H/D exchange reactions of bradykinin (M + 3H)(3+) ions with D2O and DE were monitored in a quadrupole ion trap mass spectrometer. The H/D exchange kinetics of both chemical probes (D2O and DI) indicate the presence of two noninterconverting reactive gas phase ion populations of bradykinin (M + 3H)(3+) at room temperature. The H/D exchange involving DI, however, generally proceeds faster than that involving D2O. The rate observations described here can be rationalized on the basis of the "relay mechanism" (see Campbell et al. J. Am. Chem. Sec. 1995, 117, 12840-12854) recently proposed to account for H/D exchange between D2O and gaseous protonated polypeptides. The higher exchange rate with DI is believed to arise primarily as a result of its lower gas-phase acidity relative to that of D2O and, secondarily, as a result of the longer bond length of DI relative to that of OD in D2O. (C) 2000 American Society for Mass Spectrometry. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP McLuckey, SA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI Stephenson, James/A-9262-2009; McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 43 TC 33 Z9 34 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD FEB PY 2000 VL 11 IS 2 BP 167 EP 171 DI 10.1016/S1044-0305(99)00137-3 PG 5 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 283DK UT WOS:000085260700008 PM 10689670 ER PT J AU Horne, CR Bergmann, U Kim, JK Striebel, KA Manthiram, A Cramer, SP Cairns, EJ AF Horne, CR Bergmann, U Kim, JK Striebel, KA Manthiram, A Cramer, SP Cairns, EJ TI Structural investigations of Li(1.5+x)Na0.5MnO(2.85)I(0.12) electrodes by Mn X-ray absorption near edge spectroscopy SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID MANGANESE-DIOXIDE; LITHIUM INSERTION; OXIDES; EXTRACTION; LIMN2O4; SYSTEM; XANES; TEMPERATURE; BATTERIES; SPINELS AB Mn K-edge X-ray absorption near edge spectroscopy (XANES) has been performed on an amorphous, Mn-based oxide, Li1.5Na0.5MnO2.85I0.12, and on electrodes containing this material to determine the changes that occur in the local atomic and electronic structure with state of charge and with cycling. Comparison of the XANES data with those from lambda-MnO2, LiMn2O4, and Li2Mn2O4 reveals that the Mn are octahedrally coordinated and reduced from Mn4+ to Mn3+ during discharge to 2 V. Additional ly, it was found that the amorphous nature of Li1.5Na0.5MnO2.85I0.12 results in less dramatic changes upon inserting Li+, leading to increased cycling stability and the potential for better rate capabilities within the 4-2 V range in comparison to LiMn2O4. (C) 2000 The Electrochemical Society. S0013-4651(99)02-024-8. All rights reserved. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Struct Biol Div, Berkeley, CA USA. Univ Texas, Texas Mat Inst, Austin, TX USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. EM craigh@nanogram.com RI Cairns, Elton/E-8873-2012 OI Cairns, Elton/0000-0002-1179-7591 NR 39 TC 23 Z9 23 U1 1 U2 8 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 EI 1945-7111 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD FEB PY 2000 VL 147 IS 2 BP 395 EP 398 DI 10.1149/1.1393208 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400001 ER PT J AU Gu, WB Wang, CY Weidner, JW Jungst, RG Nagasubramanian, G AF Gu, WB Wang, CY Weidner, JW Jungst, RG Nagasubramanian, G TI Computational fluid dynamics modeling of a lithium/thionyl chloride battery with electrolyte flow SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID LITHIUM; CELLS AB A two-dimensional model is developed to simulate discharge of a lithium/thionyl chloride primary battery. As in earlier one-dimensional models, the model accounts for transport of species and charge, and electrode porosity variations and electrolyte flow induced by the volume reduction caused by electrochemical reactions. Numerical simulations are performed using a finite volume method of computational fluid dynamics. The predicted discharge curves for various temperatures show good agreement with published experimental data, and are essentially identical to results published for one-dimensional models. The detailed two-dimensional flow simulations show that the electrolyte is replenished from the cell head space predominantly through the separator into the front of the cathode during most parts of the discharge, especially for higher cell temperatures. (C) 2000 The Electrochemical Society. S0013-4651(99)06-102-9. All rights reserved. C1 Penn State Univ, Dept Mech Engn, GATE Ctr Adv Energy Storage, University Pk, PA 16802 USA. Univ S Carolina, Dept Chem Engn, Ctr Electrochem Engn, Columbia, SC 29208 USA. Sandia Natl Labs, Lithium Battery Res & Dev Dept, Albuquerque, NM 87185 USA. RP Gu, WB (reprint author), Penn State Univ, Dept Mech Engn, GATE Ctr Adv Energy Storage, University Pk, PA 16802 USA. RI Wang, Chao-Yang/C-4122-2009; OI Weidner, John/0000-0002-3928-9740 NR 13 TC 24 Z9 24 U1 2 U2 12 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 FEB PY 2000 VL 147 IS 2 BP 427 EP 434 DI 10.1149/1.1393213 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400006 ER PT J AU Ren, XM Springer, TE Zawodzinski, TA Gottesfeld, S AF Ren, XM Springer, TE Zawodzinski, TA Gottesfeld, S TI Methanol transport through nafion membranes - Electro-osmotic drag effects on potential step measurements SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID FUEL-CELL; POLYMER ELECTROLYTES; EXCHANGE MEMBRANES; WATER TRANSPORT; PROTON; ACID; ELECTROOXIDATION; CROSSOVER; PERFORMANCE; CATALYST AB This paper describes methanol flux measurements across Nafion, 1100 equivalent weight membranes under conditions of a direct methanol fuel cell but in which methanol is completely electro-oxidized on the opposite side in an inert atmosphere at sufficiently high electrode potential. Both the diffusion coefficient and the methanol concentration in the membrane were determined from the measured transient limiting current density following a potential step. Corrections for electro-osmotic drag effects are developed and found necessary even for low MeOH concentrations. The results agree well with those obtained from nuclear magnetic resonance measurements. The partition coefficient [p = [MeOH](membrane)/[MeOH](solution)] was approximately constant for the membranes in contact with methanol solutions of various concentration and from room temperature to 90 degrees C. The activation energy of methanol diffusion in a fully hydrated Nafion membrane between 30 and 130 degrees C is 4.8 kcal mol(-1), and that for protonic conduction under the same conditions is 2.3 kcal mol(-1). For a membrane dried in vacuum at above 100 degrees C, lower values of methanol permeation rate and protonic conductance were found. (C) 2000 The Electrochemical Society. S0013-4651(99)03-015-3. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ren, XM (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI ren, xiaoming/F-3953-2011 NR 41 TC 406 Z9 415 U1 1 U2 64 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 FEB PY 2000 VL 147 IS 2 BP 466 EP 474 DI 10.1149/1.1393219 PG 9 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400012 ER PT J AU Prakash, J Redey, L Vissers, DR AF Prakash, J Redey, L Vissers, DR TI Electrochemical behavior of nonporous Ni/NiCl2 electrodes in chloroaluminate melts SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID SODIUM AB The electrochemical behavior of nonporous Ni/NiCl2: electrodes was studied using an Al/Na[AlCl4]-NaCl/NiCl2/Ni cell in which the capacities of the fell were limited by the Ni/NiCl2 electrode. The limiting mechanism of the electrode was found to be associated with formation of NiCl2 on the surface of the nickel electrode. This phenomenon limits the mass-transfer processes of the nonporous electrode and thus its area capacity density. Based on the results of these investigations, an electrochemical model of the electrode reactions was developed which predicts the performance characteristics of porous Ni/NiCl2 electrodes for various conditions of operation. Modifying the electrolyte with the NaBr, Nal, and sulfur additives was found to produce higher nickel utilization and lower impedance values due to doping effects, which is believed to open up the lattice for better mass transport. Solubility of the nicker chloride in sodium-chloroaluminate melts as a function of temperature and additives was also determined. The solubility measurements indicated that the solubility of nickel chloride in the chloroaluminate melt is strongly dependent on the operational temperature of the cell and the chemical additives present in the electrolyte. The results of this study clearly indicate the importance of the chemical additives, basicity of the melt, and the lower operating temperature of the Na/NiCl2 cell for improved performance and cycle life. (C) 2000 The Electrochemical Society. S0013-4651(99)06-142-X. All rights reserved. C1 IIT, Dept Chem & Environm Engn, Ctr Electrochem Sci & Engn, Chicago, IL 60616 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Prakash, J (reprint author), IIT, Dept Chem & Environm Engn, Ctr Electrochem Sci & Engn, Chicago, IL 60616 USA. NR 15 TC 23 Z9 25 U1 0 U2 7 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 FEB PY 2000 VL 147 IS 2 BP 502 EP 507 DI 10.1149/1.1393224 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400017 ER PT J AU Neudecker, BJ Dudney, NJ Bates, JB AF Neudecker, BJ Dudney, NJ Bates, JB TI "Lithium-free" thin-film battery with in situ plated Li anode SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID NICKEL OXIDES LI-X(MNYNI1-Y)(2-X)O-2; ATOMIC-FORCE MICROSCOPY; DEPOSITION PROCESSES; ELECTROLYTES; ELECTROCHEMISTRY; MORPHOLOGY; DENSITY AB The "Li-free'' thin-film battery with the cell configuration Li diffusion blocking overlayer/Cu/solid lithium electrolyte (Lipon)/LiCoO2 is activated by in situ plating of metallic Li at the Cu anode current collector during the initial charge. Electrochemical cycling between 4.2 and 3.0 V is demonstrated over 1000 cycles at 1 mA/cm(2) or over 500 cycles at 5 mA/cm(2). As corroborated by scanning electron microscopy during electrochemical cycling, the overlayer is imperative for a high cycle stability; otherwise the plated Li rapidly develops a detrimental morphology, and the battery loses most of its capacity within a few cycles. The Li-free thin-film battery retains the high potential of a Li cell while permitting its fabrication in air without the complications of a metallic Li anode. Thus, the Li-free thin-film battery survives solder reflow conditions, simulated by a rapid heating to 250 degrees C for 10 min in air followed by quenching to room temperature, without any signs of degradation. (C) 2000 The Electrochemical Society. S0013-4651(99)06-007-3. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Neudecker, BJ (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Dudney, Nancy/I-6361-2016 OI Dudney, Nancy/0000-0001-7729-6178 NR 35 TC 206 Z9 216 U1 20 U2 162 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 FEB PY 2000 VL 147 IS 2 BP 517 EP 523 DI 10.1149/1.1393226 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400019 ER PT J AU Jeffcoate, CS Isaacs, HS Aldykiewicz, AJ Ryan, MP AF Jeffcoate, CS Isaacs, HS Aldykiewicz, AJ Ryan, MP TI Chromate in conversion coatings: A XANES study of its concentration and mobility SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID X-RAY ABSORPTION; SPECTROSCOPY; ALUMINUM; CHEMISTRY AB Samples of pure aluminum were prepared with four different areas on one surface: etched aluminum, etched aluminum exposed to various electrolytes, Alodine treated aluminum, and Alodine treated aluminium exposed to electrolyte. X-ray absorption near-edge structure (XANES) was used to measure both the distribution of chromium and the proportion of hexavalent chromium. The spatial distribution of the chromium species was mapped following exposure to a range of electrolytes: Samples were exposed for 499 and 835 h to 18 M Omega deionized water. 0.5 M NaCl, 0.5 M Na2SO4, and 0.5 M Na2SO3. Immersion in water and sulfate had a minimal effect on the ionic state and location of chromium species. Immersion in chloride induced crevice corrosion attack, as indicated by a reduction in the Cr content at the interface between the exposed and protected Alodine treated areas. Small losses in Cr attributable to the loss of Cr(VI) were also found on the exposed Alodine treated areas. Exposure to sulfite caused the most dramatic changes. The total chromium content of the exposed Alodine decreased by 13%, and the amount of Cr(VI) decreased by 69% of its original value. There was a marked deposition of chromium as Cr(III) on the etched exposed aluminum close to the Alodine interface. (C) 2000 The Electrochemical Society. S0013-4651(99)02-053-4. All rights reserved. C1 Ohio State Univ, Fontana Corros Ctr, Columbus, OH 43210 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Jeffcoate, CS (reprint author), Ohio State Univ, Fontana Corros Ctr, Columbus, OH 43210 USA. NR 21 TC 51 Z9 51 U1 1 U2 3 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 FEB PY 2000 VL 147 IS 2 BP 540 EP 547 DI 10.1149/1.1393229 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400022 ER PT J AU Paddison, SJ Paul, R Zawodzinski, TA AF Paddison, SJ Paul, R Zawodzinski, TA TI A statistical mechanical model of proton and water transport in a proton exchange membrane SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID POLYMER ELECTROLYTES; ION AB We present here a mathematical model that focuses on the computation of the effective friction coefficient of an hydronium ion in a water-filled pore of a proton-exchange membrane (PEM) with a nonuniform charge distribution on the walls of the pore. The total Hamiltonian is derived for the hydronium ion as it moves through the hydrated pore and is affected by the net potential due to inter action with the solvent molecules and the pendant side chains. The corresponding probability density is derived through solution of the Liouville equation, and this probability density is then used to compute the friction tensor for the hydronium ion. The conventionally derived continuum-model friction coefficient is then "corrected' with the effective friction coefficient computed in this model, and then the corresponding proton diffusion coefficient is calculated. For a Nafion(R) membrane pore with six water molecules associated with each fixed anionic site (a total of 36 sites) and experimentally estimated pore parameters, the model predicts a proton diffusion coefficient of 5.05 x 10(-10) m(2) s(-1). A similar calculation for a pore containing 13 water molecules/SO3- resulted in a diffusion coefficient of 8.36 x 10(-10) m(2) s(-1). Both of these theoretically calculated values are in good agreement with experimentally measured diffusion coefficients. (C) 2000 The Electrochemical Society. S0013-4651(99)06-060-7. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Elect & Electrochem Mat & Devices Grp, Los Alamos, NM 87545 USA. Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP Paddison, SJ (reprint author), Univ Calif Los Alamos Natl Lab, Elect & Electrochem Mat & Devices Grp, Los Alamos, NM 87545 USA. RI Paddison, Stephen/B-2935-2014 NR 26 TC 120 Z9 123 U1 1 U2 25 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 FEB PY 2000 VL 147 IS 2 BP 617 EP 626 DI 10.1149/1.1393243 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400036 ER PT J AU Zhang, AP Dang, G Ren, F Cao, XA Cho, H Lambers, ES Pearton, SJ Shul, RJ Zhang, L Baca, AG Hickman, R Van Hove, JM AF Zhang, AP Dang, G Ren, F Cao, XA Cho, H Lambers, ES Pearton, SJ Shul, RJ Zhang, L Baca, AG Hickman, R Van Hove, JM TI Cl-2/Ar high-density-plasma damage in GaN Schottky diodes SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID FIELD-EFFECT TRANSISTORS; ETCHING-INDUCED DAMAGE; NOISE AB Inductively coupled plasma etching of metallized GaN Schottky diodes in Cl-2/Ar discharges produces reductions in both reverse breakdown voltage and Schottky barrier height. The extent of these reductions is a function of both ion energy and ion flux. Two different postetch treatments were performed in an attempt to remove the ion-damaged GaN surface layer, namely, annealing in N-2 or W-ozone oxidation followed by dissolution of the oxide. Both treatments provide only partial restoration of the diode properties. (C) 2000 The Electrochemical Society. S0013-4651(99)04-052-5. All rights reserved. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SVT Associates, Eden Prairie, MN 55344 USA. RP Zhang, AP (reprint author), Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NR 29 TC 11 Z9 11 U1 3 U2 7 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 FEB PY 2000 VL 147 IS 2 BP 719 EP 722 DI 10.1149/1.1393258 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 283UL UT WOS:000085294400051 ER PT J AU Jimenez-Pique, E Dominguez-Rodriguez, A Martinez-Fernandez, J Lara-Curzio, E Singh, M AF Jimenez-Pique, E Dominguez-Rodriguez, A Martinez-Fernandez, J Lara-Curzio, E Singh, M TI Microstructure and mechanical properties of superplastically joined yttria-partially-stabilized zirconia (Y-PSZ) ceramics SO JOURNAL OF THE EUROPEAN CERAMIC SOCIETY LA English DT Article DE joining; mechanical properties; microstructure-final; plasticity; ZrO2-Y2O3 ID FLOW AB Joining of oxide ceramics has been recognized as a key issue in their successful utilization in a variety of demanding, high temperature applications. Superplastic joining of yttria-partially-stabilized zirconia (Y-PSZ) ceramics has been carried out to avoid the deleterious effects of joint interlayer materials. Microstructural characterization of superplastically formed joints indicate that the joint interface is indistinguishable from the bulk and that there is not grain growth across the interface. Compression tests conducted on double-notch specimens show that very good bonding was achieved in the superplastic joining process. From these experiments an underestimation of the shear strength was obtained as the specimens failed in the bulk. The room temperature flexural strength of joints measured had values up to 185 MPa. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Sevilla, Dept Fis Mat Condensada, Seville 41080, Spain. Div Met & Ceram, Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Dynacs Engn Co, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dominguez-Rodriguez, A (reprint author), Univ Sevilla, Dept Fis Mat Condensada, Box 1065, Seville 41080, Spain. RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; Jimenez-Pique, Emilio/0000-0002-6950-611X; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 10 TC 9 Z9 9 U1 1 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0955-2219 J9 J EUR CERAM SOC JI J. European Ceram. Soc. PD FEB PY 2000 VL 20 IS 2 BP 147 EP 151 DI 10.1016/S0955-2219(99)00154-5 PG 5 WC Materials Science, Ceramics SC Materials Science GA 275RU UT WOS:000084834600008 ER PT J AU Noda, T Suzuki, H Lyman, JL Newnam, BE AF Noda, T Suzuki, H Lyman, JL Newnam, BE TI Silicon isotope separation by the irradiation of infrared free electron laser SO JOURNAL OF THE JAPAN INSTITUTE OF METALS LA Japanese DT Article DE isotope separation; silicon isotope; free electron laser; tetra-fluorosilane; hexa-fluorodisilane AB Free electron laser (FEL) was irradiated to Si2F6 at 1000, 800 and 400 cm(-1) bands, respectively, where the infrared absorption occurs. The isotope ratios of Si-28, Si-29 and Si-30 in the SiF4 products were measured as a function of wavenumber of the laser using an IR spectrometer. Obvious concentration of Si-29 and Si-30 was detected at all absorption bands. Especially it was the first time to observe the isotopical selective decomposition of Si2F6 at 800 and 400 cm(-1) bands. The enrichment of Si-30 at the 1000 cm(-1) band was rather lower than that by pulse CO2 laser. The main reason was considered due to collisions among gas molecules during the longer pulse of the FEL compared to that of the CO2 laser. C1 Natl Res Inst Met, Tsukuba, Ibaraki 3050047, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Noda, T (reprint author), Natl Res Inst Met, 1-2-1 Sengen, Tsukuba, Ibaraki 3050047, Japan. NR 6 TC 0 Z9 0 U1 0 U2 1 PU JAPAN INST METALS PI SENDAI PA 1-14-32, ICHIBANCHO, AOBA-KU, SENDAI, 980-8544, JAPAN SN 0021-4876 EI 1880-6880 J9 J JPN I MET JI J. Jpn. Inst. Met. PD FEB PY 2000 VL 64 IS 2 BP 174 EP 175 PG 2 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 304FF UT WOS:000086472000014 ER PT J AU Averitt, RD Rodriguez, G Siders, JLW Trugman, SA Taylor, AJ AF Averitt, RD Rodriguez, G Siders, JLW Trugman, SA Taylor, AJ TI Conductivity artifacts in optical-pump THz-probe measurements of YBa2Cu3O7 SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID 2-FLUID INTERPRETATION; TERAHERTZ; SPECTROSCOPY; SUPERCONDUCTORS; DYNAMICS; GAP AB Transient changes in the complex conductivity of the high-temperature superconductor YBa2Cu3O7 have been measured with optical-pump THz-probe spectroscopy. Artifacts in the conductivity arise when optical excitation induces changes in the material response that occur on a time scale comparable with or faster than the THz pulse width. A model is presented that agrees with experiments and provides insight in distinguishing between artifacts and real features in transient conductivity measurements. (C) 2000 Optical Society of America [S0740-3224(00)01102-4]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Averitt, RD (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI Rodriguez, George/G-7571-2012 OI Rodriguez, George/0000-0002-6044-9462 NR 19 TC 43 Z9 44 U1 0 U2 10 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 FEB PY 2000 VL 17 IS 2 BP 327 EP 331 DI 10.1364/JOSAB.17.000327 PG 5 WC Optics SC Optics GA 283AZ UT WOS:000085255100021 ER PT J AU Konno, H Yamamoto, N Lomdahl, PS AF Konno, H Yamamoto, N Lomdahl, PS TI Method of nonlinear transformation for obtaining approximate analytic solution of nonlinear ordinary differential equation. II SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article DE nonlinear transformation; double exponential function; approximate analytic solution; nonlinear third order ordinary differential equation; harmonic balance method AB It is shown that the method of nonlinear transformation (NTR) is a powerful tool for obtaining approximate analytic solutions of nonlinear ordinary differential equations (ODEs), Special attention is paid to the performance of a family of double exponential NTRs. Applications of the double exponential NTRs to some nonlinear third order ODEs in the normal form are given with numerical examples. C1 Univ Tsukuba, Inst Informat Sci & Elect, Tsukuba, Ibaraki 3058573, Japan. Univ Tsukuba, Sch Engn Syst, Tsukuba, Ibaraki 3058573, Japan. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Konno, H (reprint author), Univ Tsukuba, Inst Informat Sci & Elect, Tsukuba, Ibaraki 3058573, Japan. NR 6 TC 1 Z9 1 U1 0 U2 1 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD FEB PY 2000 VL 69 IS 2 BP 362 EP 368 DI 10.1143/JPSJ.69.362 PG 7 WC Physics, Multidisciplinary SC Physics GA 289DY UT WOS:000085606300016 ER PT J AU Gehring, PM Lee, SH Hirota, K Masuda, T Uchinokura, K Hase, M Shirane, G AF Gehring, PM Lee, SH Hirota, K Masuda, T Uchinokura, K Hase, M Shirane, G TI Cold neutron inelastic scattering measurements of the spin-Peierls and antiferromagnetic excitations in Si-doped CuGeO3 single crystals SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article DE CuGe1-xSixO3; spin-Peierls excitation; antiferromagnetic spin wave; cold neutrons ID COMPOUND CUGEO3; SYSTEM CUGEO3; TRANSITION; STATE AB Cold neutron inelastic scattering experiments on four CuGe1-xSixO3 single crystals with x = 0, 0.004, 0.01, and 0.02 have been performed to study the effects of Si doping on the antiferromagnetic (AFM) and spin-Peierls (SP) excitations with high energy resolution. The intrinsic energy width Gamma of the AFM excitation measured along the c(x) ([001]) direction near the magnetic zone center (0. 1, 1/2) (q = 0) varies as q(2) for q less than or equal to 0.032 Angstrom(-1) = 0.06q(ZB). This observation directly supports the recent theoretical predictions of Saito and Fukuyama. For pure CuGeO3 lie intrinsic SP excitation energy width appears to be resolution-limited up tl, 0.085 Angstrom(-1) Upon doping, the widths of the SP excitations increase dramatically, but they are weakly g-dependent in the range we investigated. At x = 0.02 the SP phase is lost. The existence of a second gap in CuGeO3, first observed by Ain et al., is also confirmed. This second gap, which is quite sharp in the pure compound, is considerably broadened at Si concentrations as low as x = 0.004. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138056, Japan. Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Gehring, PM (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. EM peter.gehring@nist.gov RI Hirota, Kazuma/C-6797-2008; Hase, Masashi/B-8900-2008; OI Hase, Masashi/0000-0003-2717-461X; Gehring, Peter/0000-0002-9236-2046 NR 25 TC 2 Z9 2 U1 0 U2 1 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD FEB PY 2000 VL 69 IS 2 BP 592 EP 597 DI 10.1143/JPSJ.69.592 PG 6 WC Physics, Multidisciplinary SC Physics GA 289DY UT WOS:000085606300042 ER PT J AU Segalman, DJ Butcher, EA AF Segalman, DJ Butcher, EA TI Suppression of regenerative chatter via impedance modulation SO JOURNAL OF VIBRATION AND CONTROL LA English DT Article DE chatter; impedance modulation; regenerative vibration; time-periodic differential-difference equation ID ANALYTICAL PREDICTION; GENERAL FORMULATION; STABILITY AB A new technique for the suppression of machine tool chatter in turning based on modulation of the system impedance is analyzed. The modulation frequency is selected as half the spindle frequency Using the method of harmonic balance and a numerical root finding scheme on the transcendental characteristic equation, stability diagrams are computed for a variety of modulation amplitudes. The stability boundaries are verified by using the Nyquist stability criterion and growth exponents computed from transient simulations of the vibratory response. It is shown in this way that the impedance modulation technique successfully scrambles the regenerative process that leads to chatter and widens the stability region (by increasing the maximum allowed cutting depth), particularly for low values of the spindle speed. C1 Sandria Corp, Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Segalman, DJ (reprint author), Sandria Corp, Sandia Natl Labs, POB 5800,MS0847, Albuquerque, NM 87185 USA. NR 25 TC 14 Z9 15 U1 0 U2 3 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 1077-5463 J9 J VIB CONTROL JI J. Vib. Control PD FEB PY 2000 VL 6 IS 2 BP 243 EP 256 DI 10.1177/107754630000600205 PG 14 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 275HB UT WOS:000084813800005 ER PT J AU O'Neill, J Eberling, IL Schuff, N Jagust, W Reed, B Soto, G Ezekiel, F Klein, G Weiner, MW AF O'Neill, J Eberling, IL Schuff, N Jagust, W Reed, B Soto, G Ezekiel, F Klein, G Weiner, MW TI Method to correlate H-1 MRSI and (18)FDG-PET SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE NAA; CMRglc; FDG-PET; proton MRSI ID POSITRON EMISSION TOMOGRAPHY; MAGNETIC-RESONANCE SPECTROSCOPY; MATTER METABOLITE DIFFERENCES; ISCHEMIC VASCULAR DEMENTIA; ALZHEIMERS-DISEASE; N-ACETYLASPARTATE; BRAIN-TUMORS; GRAY-MATTER; SEGMENTATION; PET AB The in vivo neuronal contribution to human cerebral metabolic rate of glucose (CMRglc), measured by (18)FDG-PET, is unknown, Examining the effect of H-1 MRSI-derived N-acetyl aspartate (NAA) concentration on positron emission tomography (PET) measures of metabolic activity might indicate the relationship of CMRglc to neuron density. In a population of 19 demented, cognitively impaired, and control subjects, the Muller-Gartner algorithm was applied to whole-brain PEI data to isolate the PET signal originating in cortical gray matter alone (GMPET). An analogous procedure applied to multislice proton MRSI data yielded the N-acetyl aspartate concentration in cortical gray matter (GMNAA), In 18 of 19 subjects, a significant linear regression (P < 0.05) resulted when GMPET was plotted against GMNAA, whereby GMPET was higher for higher GMNAA, This suggests that CMRglc rises linearly with increasing neuron density in gray matter. This method may be used to investigate the relationship of CMRglc to neurons in various conditions. (C) 2000 Wiley-Liss, Inc. C1 Vet Affairs Med Ctr, Magnet Resonance Unit, San Francisco, CA 94121 USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif Davis, Dept Neurol, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Weiner, MW (reprint author), Vet Affairs Med Ctr, Magnet Resonance Unit, 114M,4150 Clement St, San Francisco, CA 94121 USA. FU NIA NIH HHS [AG10129, AG10897, AG12535, P01 AG012435, P30 AG010129, R01 AG010897, U01 AG012535] NR 39 TC 26 Z9 26 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn. Reson. Med. PD FEB PY 2000 VL 43 IS 2 BP 244 EP 250 DI 10.1002/(SICI)1522-2594(200002)43:2<244::AID-MRM11>3.0.CO;2-2 PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 278ML UT WOS:000084993500011 PM 10680688 ER PT J AU Kim, JC Schilling, CH Tomasik, P Auh, KH AF Kim, JC Schilling, CH Tomasik, P Auh, KH TI Plasticizing dense alumina slurries with mono- and di-saccharides SO MATERIALS LETTERS LA English DT Article DE alumina; Al2O3; alumina slurries; densification; plasticity; creep; burger model; slurry; mono-saccharide; di-saccharide ID PARTICLE PACKING; CONSOLIDATION; SUSPENSIONS; RHEOLOGY; AL2O3 AB Rheological properties of dense alumina slurries with different mono- and di-saccharides were studied in order to increase the solid content of dense slurries using creep testing method. Creep test showed good correlations with Burger model which is expressed as an exponential function of time. Among several mono- and di-saccharides studied here, fructose and sucrose were most effective in making dense alumina slurry plastic than other mono- and di-saccharides. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Hanyang Univ, Ceram Mat Res Inst, Seongdong Gu, Seoul 133791, South Korea. Univ Agr, Dept Chem & Phys, Krakow, Poland. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Kim, JC (reprint author), Hanyang Univ, Ceram Mat Res Inst, Seongdong Gu, 17 HanengdangDong, Seoul 133791, South Korea. NR 21 TC 9 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD FEB PY 2000 VL 42 IS 4 BP 221 EP 224 DI 10.1016/S0167-577X(99)00187-1 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 280AX UT WOS:000085080800002 ER PT J AU Kass, MD AF Kass, MD TI Ultrasonically induced fragmentation and strain in alumina particles SO MATERIALS LETTERS LA English DT Article DE alumina; sonication; fragmentation; sintering; strain energy ID HIGH-PURITY ALUMINA AB High purity alumina particles were sonicated in distilled water at 20 kHz. Ultrasonic fragmentation of the alumina particles produced a fine particle fraction, which was less than 1 mu m in diameter. This fraction became more pronounced with increased duration and applied power. Particle fragmentation was observed to increase slightly with large increases in slurry density, indicating that the formation and collapse of cavitation bubbles were relatively unaffected by the particulate loading levels. Of great importance, the sonified powders exhibited an exotherm consistent with lattice strain energy release, thereby potentially providing an additional driving force for densification during sintering. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Engn Technol Div, Oak Ridge, TN 37831 USA. RP Kass, MD (reprint author), Oak Ridge Natl Lab, Engn Technol Div, POB 2009,Bldg 9108,Mail Stop 8088, Oak Ridge, TN 37831 USA. NR 15 TC 12 Z9 12 U1 3 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD FEB PY 2000 VL 42 IS 4 BP 246 EP 250 DI 10.1016/S0167-577X(99)00192-5 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 280AX UT WOS:000085080800007 ER PT J AU Nelson, PW Murray, JD Perelson, AS AF Nelson, PW Murray, JD Perelson, AS TI A model of HIV-1 pathogenesis that includes an intracellular delay SO MATHEMATICAL BIOSCIENCES LA English DT Article DE HIV; delay; viral life cycle; T-cells ID DYNAMICS IN-VIVO; VIRAL DYNAMICS; INFECTION; THERAPY; VIRUS; LYMPHOCYTES; RESISTANCE; DECAY; AIDS; TIME AB Mathematical modeling combined with experimental measurements have yielded important insights into HIV-1 pathogenesis, For example, data from experiments in which HIV-infected patients are given potent antiretroviral drugs that perturb the infection process have been used to estimate kinetic parameters underlying HIV infection. Many of the models used to analyze data have assumed drug treatments to be completely efficacious and that upon infection a cell instantly begins producing virus. We consider a model that allows for less then perfect drug effects and which includes a delay in the initiation of virus production. We present detailed analysis of this delay differential equation model and compare the results to a model without delay. Our analysis shows that when drug efficacy is less than 100%, as may be the case in vivo, the predicted rate of decline in plasma virus concentration depends on three factors: the death rate of virus producing cells, the efficacy of therapy, and the length of the delay. Thus, previous estimates of infected cell loss rates can be improved upon by considering more realistic models of viral infection. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Duke Univ, Dept Math, Durham, NC 27708 USA. Univ Washington, Dept Appl Math, Seattle, WA 98195 USA. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Mail Stop K710, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RR06555] NR 31 TC 177 Z9 184 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0025-5564 J9 MATH BIOSCI JI Math. Biosci. PD FEB PY 2000 VL 163 IS 2 BP 201 EP 215 DI 10.1016/S0025-5564(99)00055-3 PG 15 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 285JF UT WOS:000085385400004 PM 10701304 ER PT J AU Becker, TL Cannon, RM Ritchie, RO AF Becker, TL Cannon, RM Ritchie, RO TI An approximate method for residual stress calculation in functionally graded materials SO MECHANICS OF MATERIALS LA English DT Article DE FGM; residual stress ID THERMAL-STRESSES; GRADIENT; OPTIMIZATION; REDUCTION; CYLINDER; SPHERE; MODEL AB Thermal residual stresses in functionally graded materials (FGMs) arise primarily from nonlinear spatial variations in the thermal expansion coefficient, but can be significantly adjusted by variations in modulus. Thermoelastic analysis of FGMs is complicated by such modulus gradients. A class of problems for which thermal stress solutions for materials with constant modulus call be used as a basis for approximations for FGMs is discussed. The size of the error in this approximation due to gradients in elastic modulus is investigated. Analytical and finite element solutions for the thermal stresses in various FGM geometries are compared to results from this approximate method, In a geometry of practical interest, a right cylinder graded along the z-axis, the error for a Ni-Al2O3 FGM was found to be within 15% for all gradients considered. The form of the approximation makes it easier to identify desirable types of spatial nonlinearity in expansion coefficient and variations in modulus; this would allow the manipulation of the location of compressive stresses. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mech Engn, Berkeley, CA 94720 USA. RP Ritchie, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 20 TC 39 Z9 39 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD FEB PY 2000 VL 32 IS 2 BP 85 EP 97 DI 10.1016/S0167-6636(99)00042-3 PG 13 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA 306RN UT WOS:000086610100002 ER PT J AU Nigg, DW Wemple, CA Risler, R Hartwell, JK Harker, YD Laramore, GE AF Nigg, DW Wemple, CA Risler, R Hartwell, JK Harker, YD Laramore, GE TI Modification of the University of Washington Neutron Radiotherapy Facility for optimization of neutron capture enhanced fast-neutron therapy SO MEDICAL PHYSICS LA English DT Article DE boron; neutron; BNCT; radiotherapy; cyclotron AB A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essentially the same fast-neutron physical depth-dose distribution as is produced by the current UW clinical system, but that also has an increased fraction of BNCT enhancement relative to the total therapeutic dose. The modified target is composed of a 5-millimeter layer of beryllium, followed by a 2.5-millimeter layer of tungsten, with a water-cooled copper backing. Measurements of the free-field neutron spectrum of the beam produced by the new target were performed using activation foils with a direct spectral unfolding technique. Water phantom measurements were performed using a tissue-equivalent ion chamber to characterize the fast-neutron depth-dose curve and sodium activation in soda-lime glass beads to characterize the thermal-neutron flux (and thus the expected neutron capture dose enhancement) as a function of depth. The results of the various measurements were quite consistent with expectations based on the design calculations for the modified target. The spectrum of the neutron beam produced by the new target features an enhanced low-energy flux component relative to the spectrum of the beam produced by the standard UW target. However, it has essentially the same high-energy neutron flux, with a reduced flux component in the mid-range of the energy spectrum. As a result, the measured physical depth-dose curve in a large water phantom has the same shape compared to the case of the standard UW clinical beam, but approximately twice the level of BNCT enhancement per unit background neutron dose at depths of clinical interest. In-vivo clinical testing of BNCT-enhanced fast-neutron therapy for canine lung tumors using the new beam was recently initiated. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)00802-6]. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Univ Washington, Dept Radiat Oncol, Seattle, WA 98195 USA. RP Nigg, DW (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 22 TC 21 Z9 21 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD FEB PY 2000 VL 27 IS 2 BP 359 EP 367 DI 10.1118/1.598839 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 286UY UT WOS:000085468300012 PM 10718140 ER PT J AU Hong, T Debroy, T Babu, SS David, SA AF Hong, T Debroy, T Babu, SS David, SA TI Modeling of inclusion growth and dissolution in the weld pool SO METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE LA English DT Article ID ALLOY-STEEL WELDS; ACICULAR FERRITE; FLUID-FLOW; HEAT AB The composition, size distribution, and number density-of oxide inclusions in weld metal are critical factors in determining weldment properties. A computational model has been developed to understand these factors, considering fluid flow and the temperature field in the weld pool during submerged are (SA) welding of low-alloy steels. The equations of conservation of mass, momentum, and energy are solved in three dimensions to calculate the velocity and temperature fields in the weld pool. The loci and corresponding thermal cycles of thousands of pride inclusions are numerically calculated in the weld pool. The inclusions undergo considerable recirculatory motion and experience strong temperature gyrations. The temperature-time history and the computed time-temperature-transformation (TTT) behavior of inclusions were then used to understand the growth and dissolution of oxide inclusions in the weld pool. The statistically meaningful characteristics of inclusion behavior in the weld pool, such as the residence time, number of temperature peaks, etc., were calculated for several thousand inclusions. The calculated trends agree with experimental observations and indicate that the inclusion formation can be described by combining thermodynamics and kinetics with the fundamentals of transport phenomena. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Hong, T (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RI Babu, Sudarsanam/D-1694-2010; DebRoy, Tarasankar/A-2106-2010 OI Babu, Sudarsanam/0000-0002-3531-2579; NR 26 TC 22 Z9 22 U1 1 U2 11 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5615 J9 METALL MATER TRANS B JI Metall. Mater. Trans. B-Proc. Metall. Mater. Proc. Sci. PD FEB PY 2000 VL 31 IS 1 BP 161 EP 169 DI 10.1007/s11663-000-0141-9 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 283CE UT WOS:000085257900017 ER PT J AU Griffiths, SK Ting, A Hruby, JM AF Griffiths, SK Ting, A Hruby, JM TI The influence of mask substrate thickness on exposure and development times for the LIGA process SO MICROSYSTEM TECHNOLOGIES LA English DT Article AB Optimizing mask substrate thickness is an important practical concern in the X-ray exposure of PMMA resists for LIGA. An overly thick substrate necessitates long exposure times due to excessive beam filtering, while a substrate too thin leads to long development times due to low absorbed doses at the PMMA bottom surface. To assist in this optimization, we have developed numerical models describing both the exposure and development of a PMMA resist. These exposure and development models are coupled in a single interactive code, permitting automated adjustment of mask substrate thickness to yield the minimum of a prescribed cost object function that depends on both the exposure and development times. Results are presented for several synchrotron sources and over a wide range of the PMMA thickness. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Griffiths, SK (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 5 TC 2 Z9 3 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-7076 J9 MICROSYST TECHNOL JI Microsyst. Technol. PD FEB PY 2000 VL 6 IS 3 BP 99 EP 102 DI 10.1007/s005420050006 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 286UT UT WOS:000085467800006 ER PT J AU Guckel, H Fischer, K Stiers, E Chaudhuri, B McNamara, S Ramotowski, M Johnson, ED Kirk, C AF Guckel, H Fischer, K Stiers, E Chaudhuri, B McNamara, S Ramotowski, M Johnson, ED Kirk, C TI Direct, high throughput LIGA for commercial applications: a progress report SO MICROSYSTEM TECHNOLOGIES LA English DT Article ID RAY AB Direct LIGA; LIGA without injection molding; has the potential to become a cost effective, high throughput form of LIGA. The process requires high energy photons; near 20,000 eV; which are best produced in facilities such as the X-ray ring at Brookhaven National Laboratory. The increased absorption lengths over lower energy photons eliminates the need for a membrane type X-ray mask. This in turn facilitates very large area X-ray masks fabricated from standard silicon wafers with 20 mu m gold absorbers. The absorption length increase in PMMA to 2 cm is used to implement stacked PMMA exposures in which 1 mm thick PMMA layers are used to produce exposed PMMA sheets. These sheets are eventually solvent bonded to working substrates with plating bases. New high energy X-ray masks have been developed. Two exposure stations at Brookhaven are operational. The recently commissioned manufacturing exposure station which uses a 22 inch scanner which can expose four separate PMMA-mask combination is in the testing phase. C1 Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Quantum Devices Inc, Barneveld, WI 53507 USA. RP Guckel, H (reprint author), Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. NR 6 TC 12 Z9 12 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-7076 J9 MICROSYST TECHNOL JI Microsyst. Technol. PD FEB PY 2000 VL 6 IS 3 BP 103 EP 105 DI 10.1007/s005420050007 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 286UT UT WOS:000085467800007 ER PT J AU Ramakrishnan, M Liu, WM DiCroce, PA Posner, A Zheng, JA Kohwi-Shigematsu, T Krontiris, TG AF Ramakrishnan, M Liu, WM DiCroce, PA Posner, A Zheng, JA Kohwi-Shigematsu, T Krontiris, TG TI Modulated binding of SATB1, a matrix attachment region protein, to the AT-rich sequence flanking the major breakpoint region of BCL2 SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID NUCLEAR MATRIX; FOLLICULAR LYMPHOMA; KU ANTIGEN; CELL-DEATH; GENE; RNA; MICROPREPARATION; TRANSLOCATIONS; PURIFICATION; POLYMERASE AB The t(14,18) chromosomal translocation that occurs in human follicular lymphoma constitutively activates the BCL2 gene and disrupts control of apoptosis. Interestingly, 70% of the t(14,18) translocations are confined to three 15-bp clusters positioned within a 150-bp region (major breakpoint region or [MBR]) in the untranslated portion of terminal exon 3, We analyzed DNA-protein interactions in the MBR, as these may play some role in targeting the translocation to this region. An 87-bp segment (87MBR) immediately 3' to breakpoint cluster 3 was essential for DNA-protein interaction monitored with mobility shift assays. We further delineated a core binding region within 87MBR: a 33-bp, very AT-rich sequence highly conserved between the human and mouse BCL2 gene (37MBR). We have purified and identified one of the core factors as the matrix attachment region (MAR) binding protein, SATB1, which is known to bind to AT-rich sequences with a high propensity to unwind. Additional factors in nuclear extracts, which we have not yet characterized further, increased SATB1 affinity for the 37MBR target four- to fivefold. Specific binding activity within 37MBR displayed cell cycle regulation in Jurkat T cells, while levels of SATB1 remained constant throughout the cell cycle, Finally, we demonstrated in vivo binding of SATB1 to the MBR, strongly suggesting the BCL2 major breakpoint region is a MAR. We discuss the potential consequences of our observations for both MBR fragility and regulatory function. C1 City Hope Natl Med Ctr, Beckman Res Inst, Div Mol Med, Duarte, CA 91010 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Krontiris, TG (reprint author), City Hope Natl Med Ctr, Beckman Res Inst, Div Mol Med, 1500 E Duarte Rd, Duarte, CA 91010 USA. FU NCI NIH HHS [R37 CA039681, CA 39681, CA51985, R01 CA039681] NR 30 TC 24 Z9 25 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD FEB PY 2000 VL 20 IS 3 BP 868 EP 877 DI 10.1128/MCB.20.3.868-877.2000 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 273XD UT WOS:000084733900015 PM 10629043 ER PT J AU Ziegler, MT Thomas, SR Danna, KJ AF Ziegler, MT Thomas, SR Danna, KJ TI Accumulation of a thermostable endo-1,4-beta-D-glucanase in the apoplast of Arabidopsis thaliana leaves SO MOLECULAR BREEDING LA English DT Article DE apoplast; biomass conversion; thermostable endo-1,4-beta-D-glucanase; transgenic Arabidopsis thaliana ID GREEN FLUORESCENT PROTEIN; CELL-WALL; EXPRESSION; PLANTS; TOBACCO; GENE; TRANSFORMATION; HYDROLASES; DEFICIENT; SEQUENCE AB Plant biomass, the most abundant renewable resource on earth, is a potential source of fermentable sugars for production of alternative transportation fuels and other chemicals. Bioconversion of plant biomass to fermentable glucose involves enzymatic hydrolysis of cellulose, a major polysaccharide constituent. Because commercially available microbial cellulases are prohibitively expensive for bioethanol processes, we have investigated the feasibility of producing these enzymes in plants as a low-cost, potentially high-volume alternative to traditional production methods. We have successfully expressed the catalytic domain of a thermostable (T-opt=81 degrees C) endo-1,4-beta-D-glucanase from the eubacterium, Acidothermus cellulolyticus, in the apoplast of tobacco BY-2 suspension cells and leaves of Arabidopsis thaliana plants. The apoplast-targeting cassette designed for this work consists of the cauliflower mosaic virus 35S promoter, the tobacco mosaic virus Omega translational enhancer, the sequence encoding the tobacco Pr1a signal peptide, and the polyadenylation signal of nopaline synthase. Recombinant E1 catalytic domain was targeted to the ER by the signal peptide and secreted into the apoplast via the default pathway. Secretion of the enzyme did not detectably affect the growth rate of transgenic BY-2 cells, although the protein was enzymatically active at elevated temperatures. Similarly, transgenic plants exhibited no abnormal phenotypes correlating with expression of the enzyme. Close agreement between independent immunochemical and activity-based assays indicates that the enzyme accumulated to concentrations up to 26% of the total soluble protein in leaves of primary A. thaliana transformants. The amount of functional endoglucanase produced illustrates that plants can accumulate very large quantities of enzyme for commercial biomass conversion. C1 Univ Colorado, Dept Mol Cellular & Dev Biol, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Biotechnol Ctr Fuels & Chem, Golden, CO 80401 USA. RP Danna, KJ (reprint author), Univ Colorado, Dept Mol Cellular & Dev Biol, Boulder, CO 80309 USA. EM danna@spot.colorado.edu NR 41 TC 82 Z9 88 U1 1 U2 17 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1380-3743 EI 1572-9788 J9 MOL BREEDING JI Mol. Breed. PD FEB PY 2000 VL 6 IS 1 BP 37 EP 46 DI 10.1023/A:1009667524690 PG 10 WC Agronomy; Plant Sciences; Genetics & Heredity; Horticulture SC Agriculture; Plant Sciences; Genetics & Heredity GA 309GT UT WOS:000086760700004 ER PT J AU Murray, JB Szoke, H Szoke, A Scott, WG AF Murray, JB Szoke, H Szoke, A Scott, WG TI Capture and visualization of a catalytic RNA enzyme-product complex using crystal lattice trapping and X-ray holographic reconstruction SO MOLECULAR CELL LA English DT Article ID HAMMERHEAD RIBOZYME; EFFICIENT CLEAVAGE; VIRUS SATELLITE; CRYSTALLOGRAPHY; MECHANISM; CORE; HAIRPIN; BINDING; MODEL; SITE AB We have determined the crystal structure of the enzyme-product complex of the hammerhead ribozyme by using a reinforced crystal lattice to trap the complex prior to dissociation and by employing X-ray holographic image reconstruction, a real-space electron density imaging and refinement procedure. Subsequent to catalysis, the cleavage site residue (C-17), together with its 2',3'-cyclic phosphate, adopts a conformation close to and approximately perpendicular to the Watson-Crick base-pairing faces of two highly conserved purines in the ribozyme's catalytic pocket (G-5 and A-6). We observe several interactions with functional groups on these residues that have been identified as critical for ribozyme activity by biochemical analyses but whose role has defied explanation in terms of previous structural analyses. These interactions may therefore be relevant to the hammerhead ribozyme reaction mechanism. C1 Univ Calif Santa Cruz, Sinsheimer Labs, Ctr Mol Biol RNA, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Sinsheimer Labs, Dept Chem & Biochem, Santa Cruz, CA 95064 USA. Lawrence Livermore Natl Labs, Livermore, CA 94551 USA. RP Scott, WG (reprint author), Univ Calif Santa Cruz, Sinsheimer Labs, Ctr Mol Biol RNA, Santa Cruz, CA 95064 USA. FU NCRR NIH HHS [1P41 RR12408-01A1]; NIAID NIH HHS [R01 AI43393-02] NR 45 TC 66 Z9 69 U1 1 U2 4 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 1097-2765 J9 MOL CELL JI Mol. Cell. PD FEB PY 2000 VL 5 IS 2 BP 279 EP 287 DI 10.1016/S1097-2765(00)80423-2 PG 9 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 289WN UT WOS:000085645100008 PM 10882069 ER PT J AU Kandrup, HE Pogorelov, IV Sideris, IV AF Kandrup, HE Pogorelov, IV Sideris, IV TI Chaotic mixing in noisy Hamiltonian systems SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE chaos; galaxies : formation; galaxies : kinematics and dynamics ID GALACTIC POTENTIALS; LYAPUNOV EXPONENTS; STOCHASTICITY; DYNAMICS; ORBITS; MODEL; CUSPS AB This paper summarizes an investigation of the effects of low-amplitude noise and periodic driving on phase-space transport in three-dimensional Hamiltonian systems, a problem directly applicable to systems like galaxies, where such perturbations reflect internal irregularities and/or a surrounding environment. A new diagnostic tool is exploited to quantify the extent to which, over long times, different segments of the same chaotic orbit evolved in the absence of such perturbations can exhibit very different amounts of chaos. First-passage-time experiments are used to study how small perturbations of an individual orbit can dramatically accelerate phase-space transport, allowing 'sticky' chaotic orbits trapped near regular islands to become unstuck on surprisingly short time-scales. The effects of small perturbations are also studied in the context of orbit ensembles with the aim of understanding how such irregularities can increase the efficacy of-chaotic mixing. For both noise and periodic driving, the effect of the perturbation scales roughly logarithmically in amplitude. For white noise, the details are unimportant: additive and multiplicative noise tend to have similar effects and the presence or absence of friction related to the noise by a fluctuation-dissipation theorem is largely irrelevant. Allowing for coloured noise can significantly decrease the efficacy of the perturbation; but only when the autocorrelation time, which vanishes for white noise, becomes so large that there is little power at frequencies comparable with the natural frequencies of the unperturbed orbit. This suggests strongly that noise-induced extrinsic diffusion, like modulational diffusion associated with periodic driving, is a resonance phenomenon. Potential implications for galaxies are discussed. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Univ Florida, Inst Fundamental Theory, Gainesville, FL 32611 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Aspen Ctr Phys, Aspen, CO USA. RP Kandrup, HE (reprint author), Univ Florida, Dept Astron, Gainesville, FL 32611 USA. NR 40 TC 21 Z9 21 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 1 PY 2000 VL 311 IS 4 BP 719 EP 732 DI 10.1046/j.1365-8711.2000.03097.x PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 285AX UT WOS:000085366900008 ER PT J AU Stoller, RE AF Stoller, RE TI Evaluation of neutron energy spectrum effects and RPV thru-wall attenuation based on molecular dynamics cascade simulations SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT SMiRT-14 Post Conference Seminar Number 2 CY AUG 25-26, 1997 CL LYON, FRANCE ID PRIMARY DAMAGE FORMATION; DISPLACEMENT CASCADES; IRON AB Displacement cascade formation in iron has been investigated by the method of molecular dynamics (MD) for cascade energies up to 40 keV. The results of these simulations have been used in the SPECOMP code to obtain effective, energy-dependent cross sections for two measures of primary damage production: (1) the number of surviving point defects expressed as a fraction of the those predicted by the standard secondary displacement model by Norgett et al., 1975 [M.J. Norgett, M.T. Robinson, and I.M. Torrens, Nucl. Eng. Des. 33, (1975) 50-54] and (2) the fraction of the surviving interstitials contained in clusters that formed during the cascade event. The primary knock-on atom (PKA) spectra for iron obtained from the SPECTER code have been used to weight these MD-based damage production cross sections in order to obtain spectrally-averaged values for several locations in commercial fission reactors and test reactors. An evaluation of these results indicates that neutron energy spectrum differences between the various environments do not lead to significant differences between the average primary damage formation parameters. In particular, spectrum-averaged defect production cross sections obtained for PWR and BWR neutron spectra were not significantly different. A representative application of the new defect production cross sections is provided by examining how they vary as a function of depth into the reactor pressure vessel wall. A slight difference was noted between the damage attenuation in a PWR vessel and a BWR vessel. This observation could be explained by a subtle difference in the energy dependence of the neutron spectra. Overall, the simulations indicate that spectrum-averaged defect production cross sections do not vary much among the various environments in light-water moderated fission reactors. As such, the results support the use of atomic displacements per atom (dpa) as a damage correlation parameter and provide guidance for choosing the primary damage source term in kinetic embrittlement models. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Stoller, RE (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Stoller, Roger/H-4454-2011 NR 13 TC 15 Z9 15 U1 0 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD FEB PY 2000 VL 195 IS 2 BP 129 EP 136 DI 10.1016/S0029-5493(99)00241-1 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279XE UT WOS:000085069700002 ER PT J AU Zhang, JM Dong, PS Brust, FW Shack, WJ Mayfield, ME McNeil, M AF Zhang, JM Dong, PS Brust, FW Shack, WJ Mayfield, ME McNeil, M TI Modeling of weld residual stresses in core shroud structures SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT SMiRT-14 Post Conference Seminar Number 2 CY AUG 25-26, 1997 CL LYON, FRANCE ID SURFACE CRACKS; FINITE AB This paper presents a computational model to predict residual stresses in a girth weld (H4) of a BWR core shroud. The H4 weld is a multi-pass submerged-are weld that joins two type 304 austenitic stainless steel cylinders. An axisymmetric solid element model was used to characterize the detailed evolution of residual stresses in the H4 weld. In the analysis, a series of advanced weld modeling techniques were used to address some specific welding-related issues, such as material melting/re-melting and history annihilation. In addition, a 3-D shell element analysis was performed to quantify specimen removal effects on residual stress measurements based on a sub-structural specimen from a core shroud. The predicted residual stresses in the H4 weld were used as the crack driving force for the subsequent analysis of stress corrosion cracking in the H4 weld. The crack growth behavior was investigated using an advanced finite element alternating method (FEAM). Stress intensity factors were calculated for both axisymmetric circumferential (360 degrees) and circumferential surface cracks. The analysis results obtained from these studies shed light on the residual stress characteristics in core shroud weldments and the effects of residual stresses on stress corrosion cracking behavior. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Battelle Columbus Labs, Columbus, OH 43202 USA. Argonne Natl Lab, Argonne, IL 60439 USA. USN, Regulatory Commiss, Washington, DC USA. RP Dong, PS (reprint author), Battelle Columbus Labs, 505 King Ave, Columbus, OH 43202 USA. EM dongp@battelle.org NR 33 TC 25 Z9 27 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD FEB PY 2000 VL 195 IS 2 BP 171 EP 187 DI 10.1016/S0029-5493(99)00251-4 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279XE UT WOS:000085069700006 ER PT J AU Colchin, RJ Maingi, R Fenstermacher, ME Carlstrom, TN Isler, RC Owen, LW Groebner, RJ AF Colchin, RJ Maingi, R Fenstermacher, ME Carlstrom, TN Isler, RC Owen, LW Groebner, RJ TI Measurement of neutral density near the X point in the DIII-D tokamak SO NUCLEAR FUSION LA English DT Article ID IMPROVED CONFINEMENT; POWER THRESHOLD; H-TRANSITION; MODEL; TRANSPORT; DIVERTOR; ASDEX; ITER AB Theories predict that neutrals play a role in the low to high (L-H) confinement mode transition in tokamak plasmas via charge exchange damping and other effects. Previous estimates of neutral damping have been based on calculations of the edge neutral density. This work introduces a new method of measuring the neutral density near the X point, where simulations predict it to be a maximum. The technique employed uses D-alpha light from a TV camera reconstructed onto a poloidal plane, along with Thomson scattering measurements of the electron temperature and density. Measured neutral densities span the range 10(9)-10(13) cm(-3). Good agreement, considering the neutral density error bars, is found between the measurements and the 2-D simulations. This work represents the first step in verifying previous 2-D simulations and in corroborating previous conclusions that the neutral damping is large enough to play a role in the L-K transition process. C1 Gen Atom Co, San Diego, CA 92138 USA. RP Colchin, RJ (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. OI Isler, Ralph/0000-0002-5368-7200 NR 28 TC 29 Z9 30 U1 1 U2 4 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD FEB PY 2000 VL 40 IS 2 BP 175 EP 180 DI 10.1088/0029-5515/40/2/303 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 289YM UT WOS:000085649600003 ER PT J AU Sober, DI Crannell, H Longhi, A Matthews, SK O'Brien, JT Berman, BL Briscoe, WJ Cole, PL Connelly, JP Dodge, WR Murphy, LY Philips, SA Dugger, MK Lawrence, D Ritchie, BG Smith, ES Lambert, JM Anciant, E Audit, G Auger, T Marchand, C Klusman, M Napolitano, J Khandaker, MA Salgado, CW Sarty, AJ AF Sober, DI Crannell, H Longhi, A Matthews, SK O'Brien, JT Berman, BL Briscoe, WJ Cole, PL Connelly, JP Dodge, WR Murphy, LY Philips, SA Dugger, MK Lawrence, D Ritchie, BG Smith, ES Lambert, JM Anciant, E Audit, G Auger, T Marchand, C Klusman, M Napolitano, J Khandaker, MA Salgado, CW Sarty, AJ TI The bremsstrahlung tagged photon beam in Hall B at JLab SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE CLAS; photon tagger; photon beam; scintillator hodoscope; time-based logic AB We describe the design and commissioning of the photon tagging beamline installed in experimental Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This system can tag photon energies over a range from 20% to 95% of the incident electron energy, and is capable of operation with beam energies up to 6.1 GeV. A single dipole magnet is combined with a hodoscope containing two planar arrays of plastic scintillators to detect energy-degraded electrons from a thin bremsstrahlung radiator. The first layer of 384 partially overlapping small scintillators provides photon energy resolution, while the second layer of 61 larger scintillators provides the timing resolution necessary to form a coincidence with the corresponding nuclear interaction triggered by the tagged photon. The definitions of overlap channels in the first counter plane and of geometric correlation between the two planes are determined using digitized time information from the individual counters. Auxiliary beamline devices are briefly described, and performance results to date under real operating conditions are presented. The entire photon-tagging system has met or exceeded its design goals. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. George Washington Univ, Dept Phys, Ctr Nucl Studies, Washington, DC 20052 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Georgetown Univ, Dept Phys, Washington, DC 20057 USA. CEA Saclay, DSM, DAPNIA, Serv Phys Nucl, Gif Sur Yvette, France. Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA. Norfolk State Univ, Dept Phys, Norfolk, VA 23504 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Montgomery Coll, Rockville, MD 20850 USA. RP O'Brien, JT (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RI Sarty, Adam/G-2948-2014 NR 13 TC 143 Z9 143 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 FEB 1 PY 2000 VL 440 IS 2 BP 263 EP 284 DI 10.1016/S0168-9002(99)00784-6 PG 22 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 279ZR UT WOS:000085077600001 ER PT J AU Aschenauer, E Bianchi, N Capitani, GP Carter, P Casalino, C Cisbani, E Coluzza, C De Leo, R De Sanctis, E De Schepper, D Djordjadze, V Filippone, B Frullani, S Garibaldi, F Hansen, JO Hommez, B Iodice, M Jackson, HE Kaiser, R Kanesaka, J Lagamba, L Muccifora, V Nappi, E Nowak, WD O'Neill, TG Potterveld, D Ryckbosch, D Sakemi, Y Sato, F Schwind, A Suetsugu, K Shibata, TA Thomas, E Tytgat, M Urciuoli, GM Van de Kerckhove, K Van de Vyver, R Yoneyama, S Zhang, LF AF Aschenauer, E Bianchi, N Capitani, GP Carter, P Casalino, C Cisbani, E Coluzza, C De Leo, R De Sanctis, E De Schepper, D Djordjadze, V Filippone, B Frullani, S Garibaldi, F Hansen, JO Hommez, B Iodice, M Jackson, HE Kaiser, R Kanesaka, J Lagamba, L Muccifora, V Nappi, E Nowak, WD O'Neill, TG Potterveld, D Ryckbosch, D Sakemi, Y Sato, F Schwind, A Suetsugu, K Shibata, TA Thomas, E Tytgat, M Urciuoli, GM Van de Kerckhove, K Van de Vyver, R Yoneyama, S Zhang, LF TI Used Optical characterization of n=1.03 silica aerogel as radiator in the RICH of HERMES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE RICH; aerogel; optical properties ID CHERENKOV AB The optical properties of silica aerogel tiles with a refractive index of 1.03 and dimensions 11 x 11 x 1 cm(3), produced by the Matsushita Electric Works (Japan), have been measured in the wavelength range from 200 to 900 nm. The tiles are used as one of the two radiators of the ring imaging Cherenkov counter of the HERMES experiment at DESY-HERA. The transmittance of light has been measured on 200 tiles by means of a double beam spectrophotometer. The light transflectance and reflectance have been measured on one tiles by means of a single-beam spectrophotometer and an integrating reflecting sphere. Typical values of the measured transmittances at a wavelength lambda = 400 nm are around 0.67. The measured transflectance increases almost linearly from 0.4 to 0.96 in the interval 200-300 nm, and remains nearly constant at the value 0.95 in the complementary lambda-range. The measured reflectance, mostly confined below 400 nm, is completely interpretable as backscattering from inside the aerogel, revealing an absence of light reflection at the aerogel surfaces. The transmittance data have been fitted with the Hunt formula, whose parameters have been used to evaluate the number of unscattered and scattered Cherenkov photons produced by aerogel. For stacks of 5 tiles and quantum efficiencies of phototubes with bialkali photocathodes, rings with up to 19 photoelectrons/event can be expected for beta = 1 particles. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy. Dipartimento Interateneo fis, I-70126 Bari, Italy. CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. DESY Zeuthen, D-15738 Zeuthen, Germany. Ist Nazl Fis Nucl, Grp Sanita, I-00161 Rome, Italy. Ist Nazl Fis Nucl, Grp Sanita, I-00161 Rome, Italy. Ist Super Sanita, Fis Lab, I-00161 Rome, Italy. Univ Rome La Sapienza, Dipartimento Fis, I-00100 Rome, Italy. Ist Nazl Fis Nucl, Sez Roma 1, I-00100 Rome, Italy. Argonne Natl Lab, Argonne, IL 60439 USA. State Univ Ghent, B-9000 Ghent, Belgium. Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. RP De Leo, R (reprint author), Ist Nazl Fis Nucl, Sez Bari, Via Amendola 173, I-70126 Bari, Italy. RI Cisbani, Evaristo/C-9249-2011 OI Cisbani, Evaristo/0000-0002-6774-8473 NR 9 TC 32 Z9 32 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 FEB 1 PY 2000 VL 440 IS 2 BP 338 EP 347 DI 10.1016/S0168-9002(99)00923-7 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 279ZR UT WOS:000085077600007 ER PT J AU Almazouzi, A Caturla, MJ Alurralde, M de la Rubia, TD Victoria, M AF Almazouzi, A Caturla, MJ Alurralde, M de la Rubia, TD Victoria, M TI Defect production and damage evolution in Al: a molecular dynamics and Monte Carlo computer simulation (vol 153, pg 105, 1999) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Correction C1 Euratom Assoc, Ctr Rech Phys Plasmas, Ecole Polytech Fed Lausanne, CH-5232 Villigen, Switzerland. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Comis Nacl Energia Atom, Ctr Atom Constituyentes, Dept Mat, RA-1429 Buenos Aires, DF, Argentina. RP Almazouzi, A (reprint author), Euratom Assoc, Ctr Rech Phys Plasmas, Ecole Polytech Fed Lausanne, CH-5232 Villigen, Switzerland. RI Caturla, Maria /D-6241-2012 OI Caturla, Maria /0000-0002-4809-6553 NR 1 TC 1 Z9 1 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 FEB PY 2000 VL 160 IS 2 BP 311 EP 311 PG 1 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 273JV UT WOS:000084704900016 ER PT J AU Namavari, M Barrio, JR Toyokuni, T Gambhir, SS Cherry, SR Herschman, HR Phelps, ME Satyamurthy, N AF Namavari, M Barrio, JR Toyokuni, T Gambhir, SS Cherry, SR Herschman, HR Phelps, ME Satyamurthy, N TI Synthesis of 8-[F-18]fluoroguanine derivatives: In vivo probes for imaging gene expression with positron emission tomography SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE 8-[F-18]fluoroganciclovir; 8-[F-18]fluuropenciclovir; 8-[F-18]fluoroacyclovir; PET; gene expression ID THYMIDINE KINASE GENE; SIMPLEX VIRUS TYPE-1; ANTIVIRAL ACTIVITY; PHARMACOKINETIC PROPERTIES; THERAPEUTIC EFFICACY; VIRAL-INFECTION; HERPES; 9-(1,3-DIHYDROXY-2-PROPOXYMETHYL)GUANINE; AGENT; CELLS AB A new method for the preparation of 8-[F-18]fluoroguanine derivatives based on a direct radiofluorination reaction has been developed. The radiofluorination of ganciclovir (1a) with [F-18]F-2 was carried out in absolute ethanol in the presence of tetraethylammonium hydroxide at room temperature to give 8-[F-18]fluoroganciclovir (3a) in an approximately 1% radiochemical yield. Similarly, 8-[F-18]fluoropenciclovir (3b), 8-[F-18]fluoroacyclovir (3c), and 8-[F-18]fluoroguanosine (3d) were synthesized from penciclovir (1b), acyclovir (1c), and guanosine (1d), respectively, using [F-18]F-2. The structural analyses of the final products (3a, 3b, 3c, and 3d) were carried out after F-18 decay by H-1, C-13, and F-18 nuclear magnetic resonance and high resolution mass spectroscopy. NUCL MED BIOL 27;2:157-162, 2000. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Univ Calif Los Angeles, Sch Med, Dept Mol & Med Pharmacol, Div Nucl Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90024 USA. Univ Calif Los Angeles, Sch Med, Inst Mol Biol, Los Angeles, CA 90024 USA. Univ Calif Los Angeles, Sch Med, Jonsson Comprehens Canc Ctr, Los Angeles, CA 90024 USA. RP Satyamurthy, N (reprint author), Univ Calif Los Angeles, Sch Med, Dept Mol & Med Pharmacol, Div Nucl Med, Los Angeles, CA 90095 USA. NR 29 TC 54 Z9 55 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD FEB PY 2000 VL 27 IS 2 BP 157 EP 162 DI 10.1016/S0969-8051(99)00095-5 PG 6 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 307XT UT WOS:000086680000007 PM 10773544 ER PT J AU Daskalov, GM Baker, RS Little, RC Rogers, DWO Williamson, JF AF Daskalov, GM Baker, RS Little, RC Rogers, DWO Williamson, JF TI Two-dimensional discrete ordinates photon transport calculations for brachytherapy dosimetry applications SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID ISOTROPIC BUILDUP FACTORS; POINT; BREMSSTRAHLUNG; FLUORESCENCE; INCOHERENT; COHERENT; I-125; LEAD AB The DANTSYS discrete ordinates computer code system is applied to quantitative estimation of water kerma rate distributions in the vicinity of discrete photon sources with energies in the 20- to 800-keV range in two-dimensional cylindrical r-z geometry. Unencapsulated sources immersed in cylindrical water phantoms of 40-cm diameter and 40-cm height are modeled in either homogeneous phantoms or shielded by IE, Fe, and Pb filters with thicknesses of 1 and 2 mean free paths. The obtained dose results are compared with corresponding photon Monte Carlo simulations. A 210-group photon cross-section library for applications in this energy range is developed and applied, together with a general-purpose 42-group library developed at Los Alamos National Laboratory, for DANTSYS calculations The accuracy of DANTSYS with the 42-group library relative to Monte Carlo exhibits large pointwise fluctuations from -42 to +84%. The major cause for the observed discrepancies is determined to be the inadequacy of the weighting function used for the 42-group library derivation. DANTSYS simulations with a finer 210-group library show excellent accuracy on and off the source transverse plane relative to Monte Carlo kerma calculations, varying from --4.9 to 3.7%. The P-3 Legendre polynomial expansion of the angular scattering function is shown to be sufficient for accurate calculations. The results demonstrate that DANTSYS is capable of calculating photon doses in very good agreement with Monte Carlo and that the multigroup cross-section library and efficient techniques for mitigation of ray effects are critical for accurate discrete ordinates implementation. C1 Natl Res Council Canada, INMS, IRS, Ottawa, ON K1A 0R6, Canada. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Washington Univ, Sch Med, St Louis, MO 63110 USA. RP Daskalov, GM (reprint author), Natl Res Council Canada, INMS, IRS, 1500 Montreal Rd, Ottawa, ON K1A 0R6, Canada. RI Rogers, David/A-1973-2008 NR 33 TC 16 Z9 16 U1 0 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 2000 VL 134 IS 2 BP 121 EP 134 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279UJ UT WOS:000085063200001 ER PT J AU Zika, MR Adams, ML AF Zika, MR Adams, ML TI Transport synthetic acceleration for long-characteristics assembly-level transport problems SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID DISCRETE-ORDINATES EQUATIONS; S-N EQUATIONS AB We apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, we take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems, Our main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. We devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, we define restriction and prolongation operations specific to the method of long characteristics to map between the Two grids. We implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; we prove that the long-characteristics discretization yields an SPD matrix. We present results of our acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Texas A&M Univ, Dept Nucl Engn, College Stn, TX 77843 USA. RP Lawrence Livermore Natl Lab, POB 808,L-023, Livermore, CA 94551 USA. EM zika@llnl.gov NR 46 TC 12 Z9 12 U1 0 U2 2 PU AMER NUCLEAR SOC PI LA GRANGE PK PA 555 N KENSINGTON AVE, LA GRANGE PK, IL 60526 USA SN 0029-5639 EI 1943-748X J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 2000 VL 134 IS 2 BP 135 EP 158 PG 24 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279UJ UT WOS:000085063200002 ER PT J AU Zika, MR Adams, ML AF Zika, MR Adams, ML TI Transport synthetic acceleration with opposing reflecting boundary conditions SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The transport synthetic acceleration (TSA) scheme is extended to problems with opposing reflecting boundary conditions. This synthetic method employs a simplified transport operator as its low-order approximation. A procedure is developed that allows the use of the conjugate gradient (CG) method to solve the resulting low-order system of equations. Several well-known transport iteration algorithms are cast in a linear algebraic form to show their equivalence to standard iterative techniques. Source iteration in the presence of opposing reflecting boundary conditions is shown to be equivalent to a (poorly) preconditioned stationary Richardson iteration, with the preconditioner defined by the method of iterating on the incident fluxes on the reflecting boundaries. The TSA method (and any synthetic method) amounts to a further preconditioning of the Richardson iteration. The presence of opposing reflecting boundary conditions requires special consideration when developing a procedure to realize the CG method for the proposed system of equations. The CG iteration may be applied only to symmetric positive definite matrices; this condition requires the algebraic elimination of the boundary angular corrections from the low-order equations. As a consequence of this elimination, evaluating the action of the resulting matrix on an arbitrary vector involves two transport sweeps and a transmission iteration. Results of applying the acceleration scheme to a simple test problem are presented. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Texas A&M Univ, Dept Nucl Engn, College Stn, TX 77843 USA. RP Zika, MR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-023, Livermore, CA 94551 USA. NR 17 TC 7 Z9 7 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 2000 VL 134 IS 2 BP 159 EP 170 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279UJ UT WOS:000085063200003 ER PT J AU Fessler, A Plompen, AJM Smith, DL Meadows, JW Ikeda, Y AF Fessler, A Plompen, AJM Smith, DL Meadows, JW Ikeda, Y TI Neutron activation cross-section measurements from 16 to 20 MeV for isotopes of F, Na, Mg, Al, Si, P, Cl, Ti, V, Mn, Fe, Nb, Sn and Ba SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID 13.4-14.9 MEV NEUTRONS; EXCITATION-FUNCTIONS; N,ALPHA REACTIONS; ENERGY-RANGE; N,P; AL-27(N,ALPHA)NA-24; FE-56(N,P)MN-56; THRESHOLD; PRODUCTS; SC-45 AB Cross sections have been measured with the activation technique at various neutron energies in the range of 16.0 to 20.5 MeV for the following 22 reactions: F-19(n, p)O-19, Na-23(n, p) Ne-23, Na-23(n,alpha)F-20, Mg-25(n, p)Na-25, Al-27(n,p)Mg-27, Si-28(n, p)Al-28, Si-29(n, p)Al-29, Si-29(n, np + pn + d)Al-28, (31)p(n, alpha)Al-28, Cl-35(n, 2n)34mCl, Cl-37(n, p)S-37, Ti-46(n, p) (SC)-S-46m, Ti-50(n, p)Sc50+m, V-51(n, p) Ti-51, Mn-55 (n, alpha)V-52, Fe-56 (n, p) Mn-56, Fe-57(n, np + pn + d)Mn-56, Fe-57(n,p)Mn-57, Nb-93(n,alpha)Y-90m, Nb-93(n, 2n)Nb-92m, Sn-119(n,p)In-119g, and Ba-138(n,2n)Ba-137m. The half-lives for the reaction products range from 11 s to 10.15 days. Quasi monoenergetic neutrons were produced via the H-3(d, n)He-4 reaction. In some cases isotopically enriched materials were used to enhance the reaction yield or to facilitate correction for interfering reactions leading to the same product. The gamma rays emitted from the irradiated samples were measured with a high-purity germanium detector. A pneumatic sample transport system was used to limit the decay of the radioactive products between neutron irradiation and gamma-ray counting. All cross sections were obtained as ratios to the standard reaction Al-27(n, alpha)Na-24, using as secondary neutron fluence references the Al-27(n, p)Mg-27 reaction as well as a calibrated Bonner sphere. Corrections have been applied for sample irradiation and counting environment geometric effects, neutron absorption and multiple scattering, time variation of neutron-source strength, neutron-source angular distributions, secondary neutrons from the target, gamma-ray absorption, and gamma-ray sum coincidences. A detailed analysis of the uncertainty sources was performed The present results are compared with other measurements and evaluated data. For seven reactions, measured cross sections have been obtained for the first time beyond 15 MeV. These new data help appreciably to resolve discrepancies in evaluated data files. C1 Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. Argonne Natl Lab, Argonne, IL 60439 USA. Japan Atom Energy Res Inst, Tokai, Ibaraki 31911, Japan. RP Fessler, A (reprint author), Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. NR 88 TC 44 Z9 44 U1 1 U2 4 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 2000 VL 134 IS 2 BP 171 EP 200 PG 30 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 279UJ UT WOS:000085063200004 ER PT J AU Slater, CO Hunter, HT AF Slater, CO Hunter, HT TI Validation of the vitamin-B6 and BUGLE-96 cross-section libraries for moderate-energy neutron and photon transport calculations SO NUCLEAR TECHNOLOGY LA English DT Article DE multigroup cross-section library; neutrons and photons; moderate energy ID 14-MEV NEUTRONS; MONTE-CARLO; TRANSMISSION; CODE; DUCT AB Newly produced multigroup cross-section libraries require detailed testing to ensure that they are suitable for the applications intended. This requires that the libraries be tested against approved experimental benchmarks and/or well-posed calculational benchmarks. Following this tradition, the recently produced fine-group VITAMIN-B6 library and its derivative BUGLE-96 broad-group library have been tested against calculational and experimental benchmarks that are sensitive to neutrons with energies in the moderate-energy, range (10.0 to 20.0 MeV). Iron is prominent in each benchmark as it is in many shielding configurations, and iron cross-section data have posed significant problems in many shielding designs. These benchmarks provide stringent tests for the iron cross sections. Calculated results obtained using the new libraries were compared to measured results or results front other calculations. In some cases, results were in good agreement. In other cases, there were significant discrepancies between results due to deficient measurements in a few comparisons and to method or data deficiencies in other comparisons. It is concluded that there is still need for further measurements and evaluations of the iron cross-section data in the energy region below 6.0 MeV. While fluxes in the moderate-energy range and the associated downscatter sources may be calculated adequately the inadequate low-energy cross sections can lead to rather large discrepancies in integral quantities such as dose or heating. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Slater, CO (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 33 TC 0 Z9 0 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 FEB PY 2000 VL 129 IS 2 BP 201 EP 217 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 277DL UT WOS:000084917400005 ER PT J AU Verbeke, JM Vujic, JL Leung, KN AF Verbeke, JM Vujic, JL Leung, KN TI Neutron beam optimization for boron neutron capture therapy using the D-D and D-T high-energy neutron sources SO NUCLEAR TECHNOLOGY LA English DT Article DE boron neutron capture therapy; neutron beam design; accelerator-based neutron source ID DESIGN AB A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of boron neutron capture therapy. Two figures-of-merit-the absorbed skin dose and the absorbed tumor dose at a given depth in the brain-are used to measure the neutron beam quality. Based on the results of this study: moderators, reflectors, and delimiters are designed and optimized to moderate the high-energy neutrons from the fusion reactions H-2(d,n)He-3 and H-3(d,n)He-4 down to a suitable energy spectrum. Two different computational models (MCNP and BNCT_RTPE) have been used to study the dose distribution in the brain. With the optimal beam-shaping assembly, a 1-A mixed denteron/triton beam of energy 150 keV accelerated onto a titanium target leads to a treatment time of 1 h. The dose near the center of the brain obtained with this configuration is >65% higher than the dose from a typical spectrum produced by the Brookhaven Medical Research Reactor and is comparable to the dose obtained by other accelerator-produced neutron beams. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Verbeke, JM (reprint author), Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. NR 29 TC 22 Z9 28 U1 0 U2 2 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 FEB PY 2000 VL 129 IS 2 BP 257 EP 278 PG 22 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 277DL UT WOS:000084917400009 ER PT J AU Naumburg, E Ellsworth, DS AF Naumburg, E Ellsworth, DS TI Photosynthesis sunfleck utilization potential of understory saplings growing under elevated CO2 in FACE SO OECOLOGIA LA English DT Article DE elevated CO2; shade tolerance; photosynthetic induction; stomatal conductance; understory trees ID LEAF GAS-EXCHANGE; LIGHT ENVIRONMENT; STOMATAL RESPONSES; CARBON GAIN; RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE; ATMOSPHERIC CO2; SUCCESSIONAL STATUS; VARIABLE SUNLIGHT; TREE SEEDLINGS; DYNAMIC LIGHT AB Few studies have evaluated elevated CO2 responses of trees in variable light despite its prevalence in forest understories and its potential importance for sapling survival. We studied two shade-tolerant species (Acer rubrum, Cornus florida) and two shade-intolerant species (Liquidambar styraciflua, Liriodendron tulipifera) growing in the understory of a Pinus taeda plantation under ambient and ambient+200 ppm CO2 in a free air carbon enrichment (FACE) experiment. Photosynthetic and stomatal responses to artificial changes in light intensity were measured on saplings to determine rates of induction gain under saturating light and induction loss under shade. We expected that growth in elevated CO2 would alter photosynthetic responses to variable Light in these understory saplings. The results showed that elevated CO2 caused the expected enhancement in steady-state photosynthesis in both high and low light, but did not affect overall stomatal conductance or rates of induction gain in the four species. Induction loss after relatively short shade periods (<6 min) was slower in trees grown in elevated CO2, than in trees grown in ambient CO2 despite similar decreases in stomatal conductance. As a result leaves grown in elevated CO2 that maintained induction well in shade had higher carbon gain during subsequent light flecks than was expected from steady-state light response measurements. Thus, when frequent sunflecks maintain stomatal conductance and photosynthetic induction during the day, enhancements of long-term carbon gain by elevated CO2 could be underestimated by steady-state photosynthetic measures. With respect to species differences, both a tolerant, A. rubrum, and an intolerant species, L. tulipifera, showed rapid induction gain, but A. rubrum also lost induction rapidly (c. 12 min) in shade. These results, as well as those from independent studies in the literature, show that induction dynamics are not closely related to species shade tolerance. Therefore, it cannot be concluded that shade-tolerant species necessarily induce faster in the variable light conditions common in understories. Although our study is the first to examine dynamic photosynthetic responses to variable light in contrasting species in elevated CO2, studies on ecologically diverse species will be required to establish whether shade-tolerant and -intolerant species show different photosynthetic responses in elevated CO2 during sunflecks. We conclude that elevated CO2 affects dynamic gas exchange most strongly via photosynthetic enhancement during induction as well as in the steady state. C1 Duke Univ, Sch Environm, Durham, NC 27708 USA. Brookhaven Natl Lab, Environm Biol & Instrumentat Div, Upton, NY 11973 USA. RP Duke Univ, Sch Environm, Durham, NC 27708 USA. EM elke.naumburg@duke.edu NR 65 TC 60 Z9 64 U1 3 U2 15 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0029-8549 EI 1432-1939 J9 OECOLOGIA JI Oecologia PD FEB PY 2000 VL 122 IS 2 BP 163 EP 174 DI 10.1007/PL00008844 PG 12 WC Ecology SC Environmental Sciences & Ecology GA 285JV UT WOS:000085386700003 PM 28308370 ER PT J AU Renusch, D Muralidharan, G Uran, S Grimsditch, M Veal, BW Wright, JK Williamson, RL AF Renusch, D Muralidharan, G Uran, S Grimsditch, M Veal, BW Wright, JK Williamson, RL TI Effect of edges and corners on stresses in thermally grown alumina scales SO OXIDATION OF METALS LA English DT Article DE alumina scales; stresses; strains; fluorescence; finite-element calculations ID CHROMIUM-DOPED SAPPHIRE; OPTICAL FLUORESCENCE; RESIDUAL-STRESSES; OXIDE SCALES; OXIDATION; ALLOYS; GENERATION; BEHAVIOR; CERAMICS; RELIEF AB Residual stress near edges and corners of thermally grown alumina scales were investigated. In this study, an edge is the intersection of two orthogonal flat surfaces and LI cor ner is the intersection of three such surfaces. Microfluorescence measurements, performed On alloys with composition Fe-28Al-5Cr (at.% bal Fe) oxidized at 900 degrees C, showed a large (>50%) reduction in hydrostatic stress in the vicinity of edges and corners. Surprisingly, significant stress reduction persists out to distances twenty to fifty times the scale thickness from the edge. Finite-element analysis calculations confirm the experimental results and provide a considerably moi e detailed picture of the stress distribution and its components and show that much Of the observed stress reduction near an edge, is due to plastic deformation of the underlying metal. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Western Michigan Univ, Kalamazoo, MI 49008 USA. EG&G Idaho Inc, Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Muralidharan, Govindarajan/J-6155-2015; OI Wright, Jill/0000-0001-8909-8144; Williamson, Richard/0000-0001-7734-3632 NR 44 TC 10 Z9 11 U1 0 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0030-770X EI 1573-4889 J9 OXID MET JI Oxid. Met. PD FEB PY 2000 VL 53 IS 1-2 BP 171 EP 191 DI 10.1023/A:1004543032584 PG 21 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 284ZH UT WOS:000085362400009 ER PT J AU Brightwell, R Fisk, LA Greenberg, DS Hudson, T Levenhagen, M Maccabe, AB Riesen, R AF Brightwell, R Fisk, LA Greenberg, DS Hudson, T Levenhagen, M Maccabe, AB Riesen, R TI Massively parallel computing using commodity components SO PARALLEL COMPUTING LA English DT Article DE massively parallel; workstation cluster; Beowulf; distributed memory; message passing; MPI AB The Computational Plant (Cplant) project at Sandia National Laboratories is developing a large-scale, massively parallel computing resource from a cluster of commodity computing and networking components. We are combining the benefits of commodity cluster computing with our expertise in designing, developing, using, and maintaining large-scale, massively parallel processing (MPP) machines. In this paper, we present the design goals of the cluster and an approach to developing a commodity-based computational resource capable of delivering: performance comparable to production-level MPP machines. We provide a description of the hardware components of a 96-node Phase I prototype machine and discuss the experiences with the prototype that led to the hardware choices for a 400-node Phase II production machine. We give a detailed description of the management and runtime software components of the cluster and offer computational performance data as well as performance measurements of functions that are critical to the management of large systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Scalable Comp Syst, Albuquerque, NM 87185 USA. CCS, IDA, Bowie, MD USA. Univ New Mexico, Dept Comp Sci, Albuquerque, NM 87131 USA. RP Brightwell, R (reprint author), Sandia Natl Labs, Scalable Comp Syst, POB 5800, Albuquerque, NM 87185 USA. NR 22 TC 47 Z9 48 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 FEB PY 2000 VL 26 IS 2-3 BP 243 EP 266 DI 10.1016/S0167-8191(99)00104-0 PG 24 WC Computer Science, Theory & Methods SC Computer Science GA 283EX UT WOS:000085264100004 ER PT J AU Han, K Zandbergen, HW Bottger, A Mittemeijer, EJ AF Han, K Zandbergen, HW Bottger, A Mittemeijer, EJ TI Crystallography of tempered iron-nitrogen martensite: the roles of (011) twin boundaries SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID ALPHA-IRON; N ALLOY; PRECIPITATION; FE AB The decomposition of iron-nitrogen martensite (alpha') containing 5.4 at.% N, was analysed by both conventional and high-resolution transmission electron microscopy of specimens annealed at 333, 373 and 403 K. As a result of the anneals, alpha" precipitates (the alpha" unit cell has ideally a composition indicated by Fe16N2) were obtained in a ferrite (alpha) matrix ('first stage of tempering). Because of the determined specific orientation relationship between alpha" and alpha'-alpha, unambiguous proof for extensive (011)-type twinning in the original martensite was obtained. The crystallography at and near the original (011)(alpha') twin boundary, after the decomposition alpha' --> alpha" + alpha was scrutinized. After decomposition three types of interface originated from the original (011)(alpha') twin boundary: alpha(T1)"-alpha(T2)", alpha(T1)-alpha(T2) and alpha(T2)"-alpha(T2): where -T1 and T2 denote the original alpha' crystals constituting the twin. It followed that the local lattice orientations of alpha" and alpha at or near the T1-T2 interface were dominated by the intrinsic precipitation process as observed in untwinned martensite, which led to particular clockwise and anticlockwise rotations of the alpha" and alpha lattices, with respect to the parent alpha', in T1 and vice versa in T2. While the alpha(T1)-alpha(T2) and alpha(T1)"-alpha(T2)" interfaces remained largely at the T1-T2 interface, the alpha(T1)"-alpha(T2) interface was tilted away from this interface to minimize the alpha"-alpha misfit strain energy. The misfit at the alpha(T1)-alpha(T2) and alpha(T1)"-alpha(T2) interfaces was largely accommodated elastically (occasionally misfit dislocations were also present). The misfit at the alpha(T1)"-alpha(T2)" interface was accommodated by a change in orientation of the (001)(alpha") lattice planes in both alpha(T1)" and alpha(T2)" near the T1-T2 interface. C1 Delft Univ Technol, Mat Sci Lab, NL-2628 AL Delft, Netherlands. RP Han, K (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RI Bottger, A.J./E-2384-2012 NR 23 TC 2 Z9 2 U1 1 U2 9 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD FEB PY 2000 VL 80 IS 2 BP 311 EP 336 PG 26 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 282TT UT WOS:000085235500004 ER PT J AU Jiang, JS Fullerton, EE Grimsditch, M Sowers, CH Pearson, J Bader, SD AF Jiang, JS Fullerton, EE Grimsditch, M Sowers, CH Pearson, J Bader, SD TI Epitaxial hard-soft magnetic heterostructures as model exchange-spring magnets SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article; Proceedings Paper CT Intenational Symposium on Magnetoelasticity and Electronic Structure of Transition Metals, Alloys and Films (ISOMES II) CY OCT 04-07, 1998 CL GERHARD MERCATOR UNIV, DUISBURG, GERMANY SP Gerhard Nercator Univ HO GERHARD MERCATOR UNIV ID PERMANENT-MAGNETS; FILMS; MAGNETORESISTANCE; SUPERLATTICES; ANISOTROPY; REMANENCE; BILAYERS; FE AB We present investigations of the magnetization reversal process in exchange-spring permanent magnets. Utilizing magnetic heterostructures, such as coupled hard-soft bilayers and multilayers whereby the deposition process provides nanometre-scale control of thickness and magnetic anisotropy, we have constructed a model system for studying the exchange hardening mechanism. Comparison of the experimental results with numerical simulations indicates that the exchange-spring behaviour can be understood from the intrinsic parameters of the hard and soft layers. The simulations are extended to estimate realistically the ultimate gain in performance that can potentially be realized in permanent magnets based on the exchange-spring principle. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Jiang, JS (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 20 TC 3 Z9 3 U1 0 U2 10 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD FEB PY 2000 VL 80 IS 2 BP 247 EP 256 DI 10.1080/13642810008208613 PG 10 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 282TV UT WOS:000085235700013 ER PT J AU Tappert, J Neumann, S Jungermann, J Kim, WS Ruckert, T Brand, RA Keune, W Kleemann, W Richomme, F Teillet, J Klose, F Maletta, H AF Tappert, J Neumann, S Jungermann, J Kim, WS Ruckert, T Brand, RA Keune, W Kleemann, W Richomme, F Teillet, J Klose, F Maletta, H TI Fe spin structure in Tb/Fe multilayers SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article; Proceedings Paper CT Intenational Symposium on Magnetoelasticity and Electronic Structure of Transition Metals, Alloys and Films (ISOMES II) CY OCT 04-07, 1998 CL GERHARD MERCATOR UNIV, DUISBURG, GERMANY SP Gerhard Nercator Univ HO GERHARD MERCATOR UNIV ID PERPENDICULAR MAGNETIC-ANISOTROPY; ULTRATHIN FERROMAGNETIC-FILMS; MOSSBAUER-SPECTROSCOPY; FE/TB MULTILAYERS; REORIENTATION TRANSITION; EARTH MULTILAYERS; THIN-FILMS; INTERFACE; TEMPERATURE; ORIENTATION AB The Fe spin structure in ultrahigh-vacuum-deposited hcp Tb(t(Tb))/bcc Fe(t(Fe)) multilayers (t(Tb) and t(Fe) are the Tb and Fe layer thicknesses respectively) with perpendicular magnetic anisotropy (PMA) and large coercivity at low temperatures was investigated by Fe-57 Mossbauer spectroscopy, the polar magneto-optical Kerr effect, and superconducting quantum interference device magnetometry. A spontaneous reversible temperature-driven Fe spin reorientation transition from orientation parallel to the film plane to an out-of plane orientation (with Fe spins tilted by an angle [theta] relative to the film normal direction) was observed upon cooling below the reorientation temperature T-R. At a fixed value of t(Tb), T-R was found to follow a t(Fe)(-1) behaviour, indicating that the PMA originates from the interfaces. Upon cooling, the perpendicular remanent magnetization shows a step-like increase near the magnetic ordering temperature of Tb, contrary to [theta](T), which exhibits no such anomaly. Apparently, strong coupling of Fe layers via magnetic Tb layers affects the perpendicular magnetic domain structure at remanence. Further, Fe-57 probe layer Mossbauer results concerning structure, composition and Fe spin orientation within Fe-on-Tb and Tb-on-Fe interfaces are reported. C1 Univ Duisburg Gesamthsch, Lab Angew Phys, D-47048 Duisburg, Germany. Univ Rouen, Grp Met Phys, F-76821 Mt St Aignan, France. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14109 Berlin, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. RP Tappert, J (reprint author), Univ Duisburg Gesamthsch, Lab Angew Phys, D-47048 Duisburg, Germany. NR 40 TC 14 Z9 14 U1 1 U2 4 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD FEB PY 2000 VL 80 IS 2 BP 257 EP 274 DI 10.1080/13642810008208614 PG 18 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 282TV UT WOS:000085235700014 ER PT J AU Khraishi, TA Hirth, JP Zbib, HM de La Rubia, TD AF Khraishi, TA Hirth, JP Zbib, HM de La Rubia, TD TI The stress field of a general circular Volterra dislocation loop: analytical and numerical approaches SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID 3D AB A closed-form analytical solution for the stress field of a circular Volterra dislocation loop, having glide and prismatic components, is obtained. Assuming linear elasticity and infinite isotropic material, the stress field is found by line integration of the Peach-Koehler equation for a circular dislocation loop. The field equations are expressed in terms of complete elliptic integrals of the first and second kinds. The general loop solution is, from the principle of superposition, the additive sum of the prismatic and glide solutions. Finally, the obtained stress solution is compared with the stress calculation results from segmented loops (six to 24 segments) having the same radius. Such comparisons are useful as a benchmarking measure for newly emerging dislocation dynamics codes which discretize a curved dislocation line in some form or another. C1 Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Khraishi, TA (reprint author), Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. NR 21 TC 23 Z9 23 U1 2 U2 10 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD FEB PY 2000 VL 80 IS 2 BP 95 EP 105 DI 10.1080/095008300176353 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 281HQ UT WOS:000085153200004 ER PT J AU Stishov, SM AF Stishov, SM TI Energy, compressibility and covalency in the carbon subgroup SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID DIAMOND AB It is shown that a scaling relation of the type K0V0/E-0 approximate to constant, where K-0, V-0 and E-0 are the bulk modulus, volume and total energy respectively at normal pressure, holds for the C subgroup of the Mendeleev periodic table of elements, which consists of C itself, Si, Ge, Sn and Pb. This means that so-called covalency does not contribute significantly to the compressibility of the corresponding substances. The extreme high value of the bulk modulus of diamond is clearly the result of its highest known atomic density. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Russian Acad Sci, Inst High Pressure Phys, Troitsk 142092, Moscow Region, Russia. RP Stishov, SM (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop H805, Los Alamos, NM 87545 USA. NR 7 TC 3 Z9 4 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD FEB PY 2000 VL 80 IS 2 BP 125 EP 128 DI 10.1080/095008300176380 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 281HQ UT WOS:000085153200007 ER PT J AU Ashworth, SP Suenaga, M AF Ashworth, SP Suenaga, M TI Experimental determination of the losses produced by the interaction of AC magnetic fields and transport currents in HTS tapes SO PHYSICA C LA English DT Article DE AC magnetic fields; transport currents; HTS tapes AB This paper presents the results of a comprehensive series of measurements by our newly developed calorimetric technique of the ac losses in high quality BSCCO-2223 tape. The measurements encompass the losses due to the simultaneous application of ac transport currents and ac magnetic fields of the same frequency; parallel or perpendicular to the tape. The variation of the losses with peak current, peak applied magnetic field and phase between current and field is reported. The results confirm our previously published work in that the losses can be estimated by assuming that only in the perpendicular field orientation do the self and applied fields interact and also that the equations previously developed for estimating losses hold for tapes with a wide range of critical currents. Based on these ideas we are able to suggest equations predicting the effect of a phase difference on losses which gives reasonable agreement with measurements. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Div Sci Mat, Upton, NY 11973 USA. RP Ashworth, SP (reprint author), Brookhaven Natl Lab, Div Sci Mat, Bldg 480,POB 5000, Upton, NY 11973 USA. NR 14 TC 42 Z9 42 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 1 PY 2000 VL 329 IS 3 BP 149 EP 159 DI 10.1016/S0921-4534(99)00564-X PG 11 WC Physics, Applied SC Physics GA 279CJ UT WOS:000085025500001 ER PT J AU Moon, JS Simmons, JA Johnson, BL Reno, JL AF Moon, JS Simmons, JA Johnson, BL Reno, JL TI Edge state propagation direction in the fractional quantum Hall regime: multi-terminal magnetocapacitance experiment SO PHYSICA E LA English DT Article DE edge states; capacitance; integer quantum Hall effect; fractional quantum Hall effect ID COMPOSITE FERMIONS; LANDAU-LEVEL; CAPACITANCE; CONDUCTANCE; CHARGE AB The propagation direction of fractional quantum Hall effect (FQHE) edge states has been investigated experimentally via the symmetry properties of the multi-terminal capacitances of a two-dimensional electron gas. Although strong asymmetries with respect to zero magnetic field appear, no asymmetries with respect to even denominator Landau level filling factor v are seen. This indicates that current-carrying FQHE edge states propagate in the same direction as integer QHE edge states. In addition, anomalous capacitance features, indicative of enhanced bulk conduction, are observed at v = 1/2 and 3/2. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Western Washington Univ, Dept Phys, Bellingham, WA 98225 USA. RP Moon, JS (reprint author), Sandia Natl Labs, Mail Stop 1415,POB 5800, Albuquerque, NM 87185 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 95 EP 99 DI 10.1016/S1386-9477(99)00057-0 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600024 ER PT J AU Fromer, N Schuller, C Chemla, DS Maranowski, K Gossard, AC AF Fromer, N Schuller, C Chemla, DS Maranowski, K Gossard, AC TI Dephasing in the presence of a two-dimensional electron gas at high magnetic fields SO PHYSICA E LA English DT Article DE coherent spectroscopy; quantum wells; two-dimensional electron gas ID QUANTUM-WELLS; SCATTERING; INTEGER AB By means of degenerate four-wave mixing (FWM), we investigate the quantum coherence of electron hole pairs in the presence of a two-dimensional electron gas in modulation-doped GaAs-AlGaAs quantum wells in the regime of the integer quantum-Hall effect. We observe large jumps in the decay time of the FWM signal at even Landau level filling factors. The main features of the experimental observations can be qualitatively reproduced by a model which takes into account the number of unoccupied states within the highest partially occupied Landau level. Furthermore, we observe quantum beats between up to three different Landau level transitions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RP Fromer, N (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, MS 2-300,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 210 EP 213 DI 10.1016/S1386-9477(99)00083-1 PG 4 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600051 ER PT J AU Woodside, MT Vale, C McCormick, KL McEuen, PL Kadow, C Maranowski, KD Gossard, AC AF Woodside, MT Vale, C McCormick, KL McEuen, PL Kadow, C Maranowski, KD Gossard, AC TI Scanned potential microscopy of edge states in a quantum Hall liquid SO PHYSICA E LA English DT Article DE scanned probe microscopy; quantum Hall effect; edge states ID REGIME; CHANNELS; BACKSCATTERING; CONDUCTORS; SCATTERING; CURRENTS; CONTACTS; ABSENCE AB Using a low-temperature atomic force microscope as a local voltmeter, we measure the Hall voltage profile in a quantum Hall conductor in the presence of a gate-induced non-equilibrium edge state population at v = 3. We observe sharp voltage drops at the sample edges which are suppressed by re-equilibrating the edge states. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. RP Woodside, MT (reprint author), Lawrence Berkeley Lab, MS 2-200, Berkeley, CA 94720 USA. NR 27 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 238 EP 241 DI 10.1016/S1386-9477(99)00115-0 PG 4 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600058 ER PT J AU Ulrichs, E Steinebach, C Schuller, C Heyn, C Heitmann, D AF Ulrichs, E Steinebach, C Schuller, C Heyn, C Heitmann, D TI Coulomb-interaction-induced crossover from confined to bulk quantum-dot states in a magnetic field SO PHYSICA E LA English DT Article DE quantum dots; Raman scattering; electronic excitations AB We have employed inelastic light scattering to investigate electronic excitations of quantum dots in a magnetic field. For small magnetic fields the dispersion of the single-particle excitations (SPEs) follows the Fock-Darwin behavior. But already at moderate fields of B greater than or equal to 0.6 T the SPEs deviate from that dispersion and follow directly the cyclotron resonance. This finding is explained by Coulomb-interaction-induced formation of bulk states in the center of the dot. Self-consistent ground-state calculations within the local-density approximation reproduce this result. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Hamburg, Inst Angew Phys, D-20355 Hamburg, Germany. Univ Hamburg, Zentrum Mikrostrukturforsch, D-20355 Hamburg, Germany. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Schuller, C (reprint author), Univ Hamburg, Inst Angew Phys, Jungiusstr 11, D-20355 Hamburg, Germany. OI Heyn, Christian/0000-0002-7147-4006 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 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 364 EP 366 DI 10.1016/S1386-9477(99)00168-X PG 3 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600086 ER PT J AU Blount, MA Moon, JS Simmons, JA Lyo, SK Wendt, JR Reno, JL AF Blount, MA Moon, JS Simmons, JA Lyo, SK Wendt, JR Reno, JL TI Magnetoconductance of independently tunable tunnel-coupled double quantum wires SO PHYSICA E LA English DT Article DE quantum point contact; magnetotransport; tunneling AB We report on our recent experimental studies of vertically coupled quantum point contacts subject to in-plane magnetic fields. Using a novel flip-chip technique, mutually aligned split gates on both sides of sub-micron thick double quantum well heterostructure define a closely coupled pair of ballistic one-dimensional (1D) constrictions. We observe quantized conductance steps due to each quantum well and demonstrate independent control of each 1D constriction width. In addition, a novel magnetoconductance feature at similar to 6 T is observed when a magnetic field is applied perpendicular to both the current and growth directions. This conductance dip is observed only when 1D subbands are populated in both the top and bottom constrictions. This data is consistent with a counting model whereby the number of subbands crossing the Fermi level changes with field due to the formation of an anticrossing in each pair of 1D subbands. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. RP Blount, MA (reprint author), Sandia Natl Labs, Mail Stop 1415,Box 5800, Albuquerque, NM 87185 USA. NR 5 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 689 EP 693 DI 10.1016/S1386-9477(99)00174-5 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600164 ER PT J AU Yi, KS Hong, SP Marinescu, DC Quinn, JJ AF Yi, KS Hong, SP Marinescu, DC Quinn, JJ TI Charge-spin coupled excitations of semiconductor quantum wells with broken spin symmetry SO PHYSICA E LA English DT Article DE spin-polarized quantum wells; collective modes; dilute magnetic semiconductors ID ELECTRON-GAS; COLLECTIVE EXCITATIONS; EXCHANGE; MODES AB The response functions and collective excitations of semiconductor quantum wells with arbitrary spin polarizations are investigated. We evaluate the charge response, the longitudinal and transverse spin response to a most general external disturbance. Numerical results for the dispersion curves are given for various degrees of spin polarization. The self-consistent spin-split subband structures are used along with the Hartree-Fock local field corrections in order to obtain numerical results. The finite degree of spin polarization introduces additional structure in the spectrum. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pusan Natl Univ, Dept Phys, Pusan 609735, South Korea. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Yi, KS (reprint author), Pusan Natl Univ, Dept Phys, Pusan 609735, South Korea. NR 15 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 802 EP 806 DI 10.1016/S1386-9477(99)00242-8 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600191 ER PT J AU Marinescu, DC Quinn, JJ Giuliani, GF AF Marinescu, DC Quinn, JJ Giuliani, GF TI Magnetic phase diagram of a semiconductor superlattice at nu=2 SO PHYSICA E LA English DT Article DE magneto-optics; coupled quantum wells AB The magnetic phase diagram of a periodic system of identical quantum wells subject to a strong magnetic field is investigated within the Hartree-Fock approximation. Weak tunneling between the wells accounts for the broadening of the individual energy levels of a single well into minibands of bandwidth Delta. For small tunneling probability, the quasi-two-dimensional system undergoes a ferromagnetic-to-paramagnetic transition as in the case of a single electron gas layer. For larger tunneling probability a critical value of Delta(c) is reached for which spin flip excitations between minibands can become soft and lead to a spin density wave coupling between the bands with Q = pi/a, with a the superlattice period. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. RP Marinescu, DC (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 7 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 807 EP 809 DI 10.1016/S1386-9477(99)00241-6 PG 3 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600192 ER PT J AU Kurdak, C Therrien, R Kycia, JB Clarke, J Campman, KL Gossard, AC AF Kurdak, C Therrien, R Kycia, JB Clarke, J Campman, KL Gossard, AC TI Observation of large conductance oscillations in a superconducting single-electron transistor coupled to a two-dimensional electron gas SO PHYSICA E LA English DT Article DE superconducting single-electron transistor; Josephson junction; two-dimensional electron gas ID INSULATOR TRANSITION AB We fabricated superconducting single-electron transistors (SETs) on a GaAs/AlGaAs heterostructure with a two-dimensional electron gas (2DEG) located 1000 Angstrom below the surface. The superconducting island is coupled to the leads by submicron tunnel junctions with a tunnel junction capacitance of 0.3 fF, and to the 2DEG by a gate capacitance of 1.5 fF. The tunnel resistances of the junctions are comparable to the quantum resistance and therefore the Coulomb blockade is suppressed by the strong Josephson coupling in these devices. In a device with a tunnel resistance of 9 k Omega, we observe large Coulomb blockade-like oscillations as a function of gate voltage with a peak-to-peak amplitude of 18e(2)/h. The dissipation of the SET is varied by changing the resistance of the 2DEG. Temperature and dissipation dependence of these large Coulomb blockade-like oscillations is explained by co-tunneling of the Cooper pairs across the SET. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RP Kurdak, C (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 12 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 852 EP 855 DI 10.1016/S1386-9477(99)00232-5 PG 4 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600203 ER PT J AU Fuhrer, MS Lim, AKL Shih, L Varadarajan, U Zettl, A McEuen, PL AF Fuhrer, MS Lim, AKL Shih, L Varadarajan, U Zettl, A McEuen, PL TI Transport through crossed nanotubes SO PHYSICA E LA English DT Article DE one-dimensional; electron transport; carbon nanotube ID CARBON NANOTUBES; ELECTRONIC-STRUCTURE; TUBULES AB In order to study the electronic properties of single-walled carbon nanotube junctions we have fabricated several devices consisting of two crossed nanotubes with electrical leads attached to each end of each nanotube. We correlate the properties of the junctions with the properties of the individual nanotubes: metal-metal, metal-semiconductor, and semiconductor-semiconductor junctions are all formed. We find that metal-metal SWNT junctions exhibit surprisingly high conductances of 0.1-0.2 e(2)/h. Semiconductor-semiconductor junctions also show significant linear response conductance. Metal-semiconductor junctions behave as D-type Schottky diodes. hll the junction types can reliably I,ass currents of hundreds of nanoamps. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Dept Phys, Berkeley, CA 94720 USA. RP Fuhrer, MS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Dept Phys, Mail Stop 2-200,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X NR 11 TC 25 Z9 25 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 868 EP 871 DI 10.1016/S1386-9477(99)00228-3 PG 4 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600207 ER PT J AU Wang, YJ Leem, YA McCombe, BD Wu, XG Peeters, FM Jones, ED Reno, JR Lee, XY Jiang, HW AF Wang, YJ Leem, YA McCombe, BD Wu, XG Peeters, FM Jones, ED Reno, JR Lee, XY Jiang, HW TI Strong resonant intersubband magnetopolaron effect in heavily modulation-doped GaAs/AlGaAs single quantum wells at high magnetic fields SO PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES LA English DT Article DE electron cyclotron resonance; electron-phonon interaction; subband ID POLARON-CYCLOTRON-RESONANCE; PHONON MODES; GAAS; HETEROSTRUCTURES AB Electron cyclotron resonance (CR) has been studied in magnetic fields up to 32 T in two heavily modulation-delta-doped GaAs/Al0.3Ga0.7As single quantum well samples. Little effect on electron CR is observed in either sample in the region of resonance with the GaAs LO phonons. However, above the LO-phonon frequency energy E-LO at B > 27 T, electron CR exhibits a strong avoided-level-crossing splitting for both samples at energies close to E-LO + (E-2 - E-1), where E-2, and E-1 are the energies of the bottoms of the second and the first subbands, respectively. The energy separation between the two branches is large, reaching a minimum of about 40 cm(-1) around 30.5 T for both samples. This splitting is due to a three-level resonance between the second LI, of the first electron subband and the lowest LL of the second subband plus an LO phonon. The large splitting in the presence: of high electron densities is due to the absence of occupation (Pauli-principle) effects in the final states and weak screening for this three-level process. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. Inst Semicond, Natl Lab Superlattices & Microstruct, Beijing, Peoples R China. Univ Instelling Antwerp, Dept Natuurkunde, B-2610 Antwerp, Belgium. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Wang, YJ (reprint author), Florida State Univ, Natl High Magnet Field Lab, 1800 E Paul Dirac Dr, Tallahassee, FL 32310 USA. EM wang@magnet.fsu.edu RI CMT, UAntwerpen Group/A-5523-2016 NR 16 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 EI 1873-1759 J9 PHYSICA E JI Physica E PD FEB PY 2000 VL 6 IS 1-4 BP 195 EP 200 DI 10.1016/S1386-9477(99)00086-7 PG 6 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 291ZX UT WOS:000085770600048 ER PT J AU Berman, GP James, DFV Hughes, RJ Gulley, MS Holzscheiter, MH Lopez, GV AF Berman, GP James, DFV Hughes, RJ Gulley, MS Holzscheiter, MH Lopez, GV TI Dynamical stability and quantum chaos of ions in a linear trap SO PHYSICAL REVIEW A LA English DT Article ID KICKED HARMONIC-OSCILLATOR; NONLINEAR RESONANCE; DIFFUSION; SYSTEMS; STATE; ATOM AB The realization of a paradigm chaotic system, namely, the harmonically driven oscillator, in the quantum domain using cold trapped ions driven by lasers is theoretically investigated. The simplest characteristics of regular and chaotic dynamics are calculated. The possibilities of experimental realization are discussed. C1 Univ Calif Los Alamos Natl Lab, Grp T13, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Grp T4, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Grp P23, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Grp P25, Los Alamos, NM 87545 USA. Univ Guadalajara, Dept Fis, Guadalajara 44420, Jalisco, Mexico. RP Berman, GP (reprint author), Univ Calif Los Alamos Natl Lab, Grp T13, POB 1663, Los Alamos, NM 87545 USA. EM gpb@lanl.gov RI James, Daniel/B-9805-2009 OI James, Daniel/0000-0003-3981-4602 NR 39 TC 4 Z9 4 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB PY 2000 VL 61 IS 2 AR 023403 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 284MV UT WOS:000085336900082 ER PT J AU Campbell, L Green, MA Brunger, MJ Teubner, PJO Cartwright, DC AF Campbell, L Green, MA Brunger, MJ Teubner, PJO Cartwright, DC TI Determination of differential cross sections for electron-impact excitation of electronic states of molecular oxygen SO PHYSICAL REVIEW A LA English DT Article ID NIGHTGLOW EMISSIONS; GROUND-STATE; SCATTERING; O2; O-2; COLLISIONS AB The development and initial results of a method for the determination of differential cross sections for electron scattering by molecular oxygen are described. The method has been incorporated into an existing package of computer programs which, given spectroscopic factors, dissociation energies and an energy-loss spectrum for electron-impact excitation, determine the differential cross sections for each electronic state relative to that of the elastic peak. Enhancements of the original code were made to deal with particular aspects of electron scattering from O-2, such as the overlap of vibrational levels of the ground state with transitions to excited states, and transitions to levels close to and above the dissocation energy in the Herzberg and Schumann-Runge continua. The utility of the code is specifically demonstrated for the "6-eV states" of O-2, where we report absolute differential cross sections for their excitation by 15-eV electrons. In addition an integral cross section, derived from the differential cross section measurements, is also reported fur this excitation process and compared against available theoretical results. The present differential and integral cross sections for excitation of the "6-eV states" of O-2 are the first to be reported in the literature for electron-impact energies below 20 eV. C1 Flinders Univ S Australia, Dept Phys, Adelaide, SA 5001, Australia. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Campbell, L (reprint author), Flinders Univ S Australia, Dept Phys, GPO Box 2100, Adelaide, SA 5001, Australia. RI Green, Michael/C-9634-2011 NR 40 TC 10 Z9 10 U1 0 U2 6 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 FEB PY 2000 VL 61 IS 2 AR 022706 DI 10.1103/PhysRevA.61.022706 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 284MV UT WOS:000085336900056 ER PT J AU Knospe, O Jellinek, J Saalmann, U Schmidt, R AF Knospe, O Jellinek, J Saalmann, U Schmidt, R TI Charge transfer and fragmentation in cluster-atom collisions SO PHYSICAL REVIEW A LA English DT Article ID DENSITY-FUNCTIONAL THEORY; OPTICAL-RESPONSE; ELECTRON-CAPTURE; TEMPERATURE-DEPENDENCE; METALLIC CLUSTERS; SODIUM CLUSTERS; SLOW COLLISIONS; CROSS-SECTIONS; IONS; C-60 AB Charge transfer and fragmentation in collisions of sodium cluster ions with caesium atoms have been investigated theoretically within a microscopic framework called nonadiabatic quantum molecular dynamics. To illustrate the complexity of nonadiabatic cluster collisions, in particular the interplay between charge transfer and fragmentation, Na-4(+) (2.7 keV) + Cs collisions are studied in detail with special emphasis on methodical aspects, It is shown that integral and exclusive charge transfer cross sections can be understood only if all types of fragmentation processes including statistical decay are taken into account. The influence of the cluster structure (isomers, temperature, size) on measured and measurable cross sections is studied for different charge transfer channels as well as for fragmentation. In particular, cross sections for the exotic formation of caesium anions in such collisions are predicted. C1 Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Stockholm Univ, S-10405 Stockholm, Sweden. Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany. RP Max Planck Inst Phys Komplexer Syst, Nothnitzer Str 38, D-01187 Dresden, Germany. NR 43 TC 19 Z9 19 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD FEB PY 2000 VL 61 IS 2 AR 022715 DI 10.1103/PhysRevA.61.022715 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 284MV UT WOS:000085336900065 ER PT J AU Zhang, HL Sampson, DH AF Zhang, HL Sampson, DH TI Effective collision strengths for hyperfine-structure transitions with inclusion of resonance effects SO PHYSICAL REVIEW A LA English DT Article ID HIGHLY CHARGED IONS; EXCITATION; IONIZATION; RATES AB Calculations are made of the resonance contribution to electron-impact excitation of Li-like Fe-57 and H-like N-14 ions to the upper hyperfine levels that produce mm lines of likely astrophysical interest. The resonance contribution is found to be very important for Fe-57, but rather unimportant for N-14. Inclusion of the effect of radiative decay is found to be slightly significant for Fe-57, but insignificant for N-14. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Zhang, HL (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, POB 1663, Los Alamos, NM 87545 USA. NR 14 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB PY 2000 VL 61 IS 2 AR 022707 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 284MV UT WOS:000085336900057 ER PT J AU Hart, GLW Klein, BM AF Hart, GLW Klein, BM TI Phonon and elastic instabilities in MoC and MoN SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE; HIGH-PRESSURE; SUPERCONDUCTIVITY; FILMS; TRANSITION AB We present several results related to the instability of MoC and MoN in the B1 (sodium chloride) structure. These compounds were proposed as potential superconductors with moderately high transition temperatures. We show that the elastic instability in B1-structure MoN, demonstrated several years ago, persists at elevated pressures, thus offering little hope of stabilizing this material without chemical doping. For MoC, another material for which stoichiometric fabrication in the B1 structure has not proven possible. we find that all of the cubic elastic constants are positive, indicating elastic stability. Instead, we find X-point phonon instabilities in MoC (and in MoN as well), further illustrating the rich behavior of carbo-nitride materials. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Hart, GLW (reprint author), Natl Renewable Energy Lab, Solid State Theory Grp, 1617 Cole Blvd, Golden, CO 80401 USA. EM ghart@nrel.gov OI Hart, Gus L. W./0000-0002-6149-9234 NR 33 TC 30 Z9 30 U1 3 U2 15 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 FEB 1 PY 2000 VL 61 IS 5 BP 3151 EP 3154 DI 10.1103/PhysRevB.61.3151 PG 4 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800007 ER PT J AU Bonca, J Gubernatis, JE Guerrero, M Jeckelmann, E White, SR AF Bonca, J Gubernatis, JE Guerrero, M Jeckelmann, E White, SR TI Stripes in a three-chain Hubbard ladder: A comparison of density-matrix renormalization group and constrained-path Monte Carlo results SO PHYSICAL REVIEW B LA English DT Article ID T-J LADDER; HARTREE-FOCK; MODEL; PHASE; MAGNETISM; STATES; HOLES; ORDER; SPINS AB Using both the density-matrix renormalization group method and the constrained-path quantum Monte Carlo method, we studied the ground-state energies and the spin and hole densities of a 12X3 Hubbard model with open boundary conditions and six holes doped away from half-filling. Results obtained with these two methods agree well in the small and intermediate U regimes. For U/t greater than or equal to 6 we find a ground-state with charge inhomogeneities consistent with stripes. C1 FMF, Dept Phys, Ljubljana, Slovenia. Jozef Stefan Inst, Ljubljana, Slovenia. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. RP Bonca, J (reprint author), FMF, Dept Phys, Ljubljana, Slovenia. RI White, Steven/B-4760-2008; Jeckelmann, Eric/C-7497-2009 OI White, Steven/0000-0003-3496-0707; Jeckelmann, Eric/0000-0002-0150-5938 NR 22 TC 24 Z9 24 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 FEB 1 PY 2000 VL 61 IS 5 BP 3251 EP 3254 DI 10.1103/PhysRevB.61.3251 PG 4 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800033 ER PT J AU Graf, MJ Balatsky, AV Sauls, JA AF Graf, MJ Balatsky, AV Sauls, JA TI Local time-reversal-symmetry breaking in d(x2-y2) superconductors SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-IMPURITIES; D(X(2)-Y(2))-WAVE SUPERCONDUCTOR; UNCONVENTIONAL SUPERCONDUCTORS; PARITY BREAKING; STATES; PHASE AB We show that an isolated impurity in a spin singlet d(x2)-(y2) superconductor generates a d(xy) order parameter with locally broken time-reversal symmetry. The origin of this effect is a coupling between the d(X2)-(y2) and the d(xy) order parameter induced by spin-orbit scattering off the impurity. The signature of locally broken time-reversal symmetry is an induced orbital charge current near the impurity, which generates a localized magnetic field in the vicinity of the impurity. We present a microscopic theory for the impurity-induced d(xy) component, discuss its spatial structure as well as the pattern of induced current and local magnetic field near the localized impurity spin. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RP Graf, MJ (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. OI Sauls, James/0000-0002-3619-2572 NR 22 TC 17 Z9 17 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 FEB 1 PY 2000 VL 61 IS 5 BP 3255 EP 3258 DI 10.1103/PhysRevB.61.3255 PG 4 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800034 ER PT J AU Berman, GP Tsifrinovich, VI AF Berman, GP Tsifrinovich, VI TI Modified approach to single-spin detection using magnetic resonance force microscopy SO PHYSICAL REVIEW B LA English DT Article AB The magnetic moment of a single spin interacting with a cantilever in magnetic resonance farce microscopy (MRFM) experiences quantum jumps in orientation rather than smooth oscillations. These jumps cannot be detected by a conventional MRFM based on observation of driven resonant oscillations of a cantilever. In this paper, we propose a method which should allow detection of the magnetic signal from a single spin using a modification of a conventional MRFM. We estimate the opportunity to detect the magnetic signal from a single proton. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Polytech Univ, IDS Dept, Metrotech Ctr 6, Brooklyn, NY 11201 USA. RP Berman, GP (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-13,MS B213, Los Alamos, NM 87545 USA. NR 9 TC 16 Z9 16 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 2000 VL 61 IS 5 BP 3524 EP 3527 DI 10.1103/PhysRevB.61.3524 PG 4 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800073 ER PT J AU Schilling, A Willemin, M Rossel, C Keller, H Fisher, RA Phillips, NE Welp, U Kwok, WK Olsson, RJ Crabtree, GW AF Schilling, A Willemin, M Rossel, C Keller, H Fisher, RA Phillips, NE Welp, U Kwok, WK Olsson, RJ Crabtree, GW TI Anisotropy of magnetization discontinuity at vortex-lattice melting in untwinned YBa2Cu3O7-delta SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; SINGLE-CRYSTALS; PHASE-TRANSITION; FLUX-LATTICE; CRITICAL-BEHAVIOR; DIMENSIONAL CROSSOVER; II SUPERCONDUCTORS; ANGULAR-DEPENDENCE; HEAT EXPERIMENTS; MIXED-STATE AB We measured the magnetic torque tau experienced by an untwinned YBa2Cu3O7-delta single crystal in external magnetic fields up to mu(0)H = 7 T below the critical temperature T-c = 93.3 K, as a function of Theta, the angle between H and the c axis of the crystal. At the vortex-lattice melting transition we observe discontinuities in both tau and (partial derivative tau/partial derivative H)(T), that are related to changes in the transverse components of the magnetization Vector M and (partial derivative M/partial derivative H)(T), respectively. We use thermodynamic relationships to determine the direction of the vector Delta M in space, and show that Delta M is always directed parallel to M. The discontinuities in magnetization Delta M and in entropy Delta S vanish slightly below the temperature where the melting field H-m(T) extrapolates to zero, which could indicate the existence of a lower critical point of the vortex-lattice melting line. From our (partial derivative tau/partial derivative H)(tau) data we are able to extract the differences in the reduced specific heat Delta C/T between the vortex-fluid and the vortex-solid phases, and we compare these results with corresponding thermal data. We finally examine the validity of standard angular scaling rules for anisotropic superconductors for the melting fields H-m(T,Theta) at temperatures as high as T/T-c= 0.99. C1 Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. IBM Corp, Div Res, Zurich Res Lab, CH-8803 Ruschlikon, Switzerland. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Argonne Natl Lab, Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. RP Schilling, A (reprint author), Univ Zurich, Inst Phys, Winterthurerstr 190, CH-8057 Zurich, Switzerland. NR 57 TC 12 Z9 12 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 FEB 1 PY 2000 VL 61 IS 5 BP 3592 EP 3603 DI 10.1103/PhysRevB.61.3592 PG 12 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800082 ER PT J AU Ozyuzer, L Zasadzinski, JF Kendziora, C Gray, KE AF Ozyuzer, L Zasadzinski, JF Kendziora, C Gray, KE TI Quasiparticle and Josephson tunneling of overdoped Bi2Sr2CaCu2O8+delta single crystals SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTING GAP ANISOTROPY; T-C SUPERCONDUCTORS; ORDER-PARAMETER; CLEAVED SURFACE; SPECTROSCOPY; TEMPERATURE; SYMMETRY; JUNCTIONS; SPECTRA; STATES AB The point contact tunneling technique is used to examine quasiparticle and Josephson currents in overdoped Bi2Sr2CaCu2O8+delta (Bi-2212) single crystals with bulk T-c values ranging from 82 K down to 62 K. Superconductor-insulator-normal-metal (SIN) tunnel junctions are formed between Bi-2212 crystals and a Au tip, which display well-resolved quasiparticle gap features including sharp conductance peaks. Reproducible superconductor- insulator-superconductor (SIS) tunnel junctions are also obtained between two pieces of the Bi-2212 crystals, resulting in simultaneous quasiparticle and Josephson currents. The dynamic conductances of both SIN and SIS junctions are qualitatively similar to those found on optimally doped Bi-2212, but with reduced gap values, e.g., Delta = 15-20 meV for T-c = 62 K. Fits to the conductance data in the gap region are obtained using a model with d(x2-y2) symmetry, and it is shown that this provides a better fit than s-wave symmetry. Both SIN and SIS tunneling conductances also display dip and hump features at high bias voltages similar to those found on optimal and underdoped crystals, indicating that these are intrinsic properties of the quasiparticles. The SIS data indicate that these features appear to be part of a larger spectrum that extends out to 300-400 mV. The Josephson current has been measured for 13 SIS junctions on the 62 K crystals with resistances varying over two decades. It is found that the maximum value depends on junction resistance in a manner consistent with Ambegaokar-Baratoff theory, but with a reduced IcRn product. C1 Argonne Natl Lab, Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. IIT, Chicago, IL 60616 USA. Izmir Inst Technol, Dept Phys, TR-35230 Izmir, Turkey. USN, Res Lab, Washington, DC 20375 USA. RP Ozyuzer, L (reprint author), Argonne Natl Lab, Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. RI Ozyuzer, Lutfi/H-3142-2011 NR 44 TC 43 Z9 43 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 2000 VL 61 IS 5 BP 3629 EP 3640 DI 10.1103/PhysRevB.61.3629 PG 12 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800087 ER PT J AU Wakimoto, S Birgeneau, RJ Kastner, MA Lee, YS Erwin, R Gehring, PM Lee, SH Fujita, M Yamada, K Endoh, Y Hirota, K Shirane, G AF Wakimoto, S Birgeneau, RJ Kastner, MA Lee, YS Erwin, R Gehring, PM Lee, SH Fujita, M Yamada, K Endoh, Y Hirota, K Shirane, G TI Direct observation of a one-dimensional static spin modulation in insulating La1.95Sr0.05CuO4 SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTING LA2-XSRXCUO4; MAGNETIC CORRELATIONS; NEUTRON-SCATTERING; DENSITY-WAVE; DOMAIN-WALLS; FLUCTUATIONS; TEMPERATURE; EXCITATIONS; TRANSPORT; LA2CUO4 AB We report the results of an extensive elastic neutron-scattering study of the incommensurate (IC) static spin correlations in La1.95Sr0.05CuO4, which is an insulating spin glass at low temperatures. Recent work by Wakimoto et nl, has revealed the presence of new two-dimensional satellite peaks in La1.95Sr0.05CuO4 at positions rotated by similar to 45 degrees in reciprocal space from those found in superconducting samples. The present neutron-scattering experiments on the same x = 0.05 crystal employ a narrower instrumental Q resolution and thereby have revealed that the crystal has only two, rather than four, orthorhombic twins at low temperatures with relative populations of 2:1. This has made possible the precise characterization of the IC elastic peaks around (1,0,0) and (0,1,0) (orthorhombic notation) in each domain separately. We find that, in a single twin, only two satellites are observed at (1,+/- 0.064,L)(ortho) and (0,1 +/- 0.064,L)(ortho), that is, the modulation vector is only along the orthorhombic b* axis. This demonstrates unambiguously that La1.95Sr0.05CuO4 has a one-dimensional rather than two-dimensional static diagonal spin modulation at low temperatures, consistent with certain stripe models. From the L dependence we conclude that the spin correlations are predominantly two dimensional. We have also reexamined the x = 0.04 crystal that previously was reported to show a single commensurate peak. By mounting the sample in the (H,K,0) zone, we have discovered that the x = 0.04 sample in fact has the same IC structure as the x = 0.05 sample. The incommensurability parameter delta for x = 0.04 and 0.05, where delta is the distance from (1/2,1/2) in tetragonal reciprocal lattice units, follows the linear relation delta similar or equal to x. These results demonstrate that the insulator to superconductor transition in the underdoped regime (0.05 less than or equal to x less than or equal to 0.06) in La2-xSrxCuO4 is coincident with a transition from diagonal to collinear static stripes at low temperatures thereby evincing the intimate coupling between the one-dimensional spin density modulation and the superconductivity. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, NCNR, Gaithersburg, MD 20889 USA. Kyoto Univ, Inst Chem Res, Uji 6100011, Japan. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Maryland, College Pk, MD 20742 USA. RP MIT, Dept Phys, Cambridge, MA 02139 USA. RI Hirota, Kazuma/C-6797-2008; Yamada, Kazuyoshi/C-2728-2009; Fujita, Masaki/D-8430-2013; OI Gehring, Peter/0000-0002-9236-2046 NR 33 TC 146 Z9 147 U1 1 U2 10 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 FEB 1 PY 2000 VL 61 IS 5 BP 3699 EP 3706 DI 10.1103/PhysRevB.61.3699 PG 8 WC Physics, Condensed Matter SC Physics GA 284LA UT WOS:000085332800095 ER PT J AU Shenderova, OA Brenner, DW Omeltchenko, A Su, X Yang, LH AF Shenderova, OA Brenner, DW Omeltchenko, A Su, X Yang, LH TI Atomistic modeling of the fracture of polycrystalline diamond SO PHYSICAL REVIEW B LA English DT Article ID BOUNDARY-CHARACTER-DISTRIBUTION; GRAIN-BOUNDARIES; MOLECULAR-DYNAMICS; BRITTLE-FRACTURE; FILMS; STRENGTH; SURFACES; SIMULATIONS; FAILURE; SILICON AB A series of molecular-dynamics simulations using a many-body interatomic potential has been performed to investigate the behavior under load of several [001] and [011] symmetrical tilt grain boundaries (GB's) in diamond. Cohesive energies, the work for fracture, maximum stresses and strains, and toughness as a function of GB type are evaluated. Results indicate that special short-period GB's possess higher strengths and greater resistance to crack propagation than GB's in nearby misorientation angles. Based on dynamic simulations, it was found that the mechanism of interface failure for GB's without preexisting flaws is not that implied by Orovan's criterion, but rather GB strength is defined by GB type instead of cleavage energy. In simulations of crack propagation within GB's on the other hand, it was found that critical stresses for crack propagation from atomistic simulation and from the Griffith criterion are consistent, indicating that GB cleavage energy is an important characteristic of GB toughness. Crack propagation in polycrystalline diamond samples under an applied load was also simulated and found to be predominantly transgranular rather than intergranular. C1 N Carolina State Univ, Raleigh, NC 27695 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Shenderova, OA (reprint author), N Carolina State Univ, Raleigh, NC 27695 USA. RI Brenner, Donald/D-1741-2009 NR 45 TC 171 Z9 176 U1 4 U2 45 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 FEB 1 PY 2000 VL 61 IS 6 BP 3877 EP 3888 DI 10.1103/PhysRevB.61.3877 PG 12 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700026 ER PT J AU Samara, GA Boatner, LA AF Samara, GA Boatner, LA TI Ferroelectric-to-relaxor crossover and oxygen vacancy hopping in the compositionally disordered perovskites KTa1-xNbxO3 : Ca SO PHYSICAL REVIEW B LA English DT Article ID RANDOM-FIELD INSTABILITY; LEAD-ZIRCONATE-TITANATE; LONG-RANGE ORDER; PHASE-TRANSITION; PRESSURE; SYSTEMS; STATES; NB AB It is shown that lattice disorder induced by Nb and Ca substitution has a strong influence on the dielectric and relaxational properties of KTaO3. Both substituents are believed to occupy off-center positions at the Ta site, and the difference in valence between the Ca2+ and Ta5+ ions leads to the formation of oxygen vacancies (V-O). Specifically, for a KTa1-xNbxO3:Ca crystal with x = 0.023 and with a 0.055 at. % Ca doping, we observe (i) a ferroelectric transition at atmospheric pressure (1 bar); (ii) a large enhancement of the transition temperature by Ca doping: (iii) a pressure-induced crossover from ferroelectric-to-relaxor behavior; (iv) the impending vanishing of the relaxer phase at high pressure; (v) the reorientation of the Ca-oxygen vacancy (Ca: V-O) pair defect; and (vi) the variation of the energetics and dynamics of this reorientation with pressure. Most of these effects are associated with Nb- and Ca-induced dipolar entities and appear to be general features of soft mode ferroelectrics with random-site polar nanodomains, The ferroelectric-to-relaxor crossover can be understood in terms of a large decrease with pressure in the correlation length among polar nanodomains-a unique property of soft ferroelectric mode systems. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Samara, GA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. OI Boatner, Lynn/0000-0002-0235-7594 NR 33 TC 62 Z9 62 U1 3 U2 22 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 FEB 1 PY 2000 VL 61 IS 6 BP 3889 EP 3896 DI 10.1103/PhysRevB.61.3889 PG 8 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700027 ER PT J AU Mittal, R Chaplot, SL Choudhury, N Loong, CK AF Mittal, R Chaplot, SL Choudhury, N Loong, CK TI Inelastic neutron scattering and lattice-dynamics studies of almandine Fe3Al2Si3O12 SO PHYSICAL REVIEW B LA English DT Article ID SILICATE GARNETS; LOWER-MANTLE; VIBRATIONAL SPECTROSCOPY; THERMODYNAMIC PROPERTIES; HYDROSTATIC COMPRESSION; ELASTIC PROPERTIES; PYROPE; TEMPERATURE; EQUILIBRIA; PHASE AB This paper reports detailed lattice dynamical studies involving experimental inelastic neutron-scattering measurements and theoretical shell model calculations of the vibrational and thermodynamic properties of the garnet mineral almandine Fe3Al2Si3O12. Inelastic neutron-scattering studies using the time-of-flight technique provide the measurement of the phonon density of stares (BOS) of almandine, which have been interpreted based on the model calculations. The calculated DOS is in good agreement with the inelastic neutron-scattering data and has been used to compute various macroscopic properties like the specific heat, thermal expansion, equation of state, and mean-square atomic displacements. C1 Bhabha Atom Res Ctr, Div Solid State Phys, Bombay 400085, Maharashtra, India. Argonne Natl Lab, Div Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Mittal, R (reprint author), Bhabha Atom Res Ctr, Div Solid State Phys, Bombay 400085, Maharashtra, India. NR 55 TC 19 Z9 19 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 FEB 1 PY 2000 VL 61 IS 6 BP 3983 EP 3988 DI 10.1103/PhysRevB.61.3983 PG 6 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700038 ER PT J AU Galanakis, I Ostanin, S Alouani, M Dreysse, H Wills, JM AF Galanakis, I Ostanin, S Alouani, M Dreysse, H Wills, JM TI Ab initio ground state and L-2,L-3 x-ray magnetic circular dichroism of Mn-based Heusler alloys SO PHYSICAL REVIEW B LA English DT Article ID HALF-METALLIC FERROMAGNETS; MULTIPLE-SCATTERING THEORY; MAGNETOOPTICAL PROPERTIES; THIN-FILMS; SUM-RULES; ABSORPTION-SPECTRA; PTMNSB; NIMNSB; SPECTROSCOPY; MULTILAYERS AB Relativistic full-potential calculations within the generalized gradient approximation (GGA) for a series of Mn-based Heusler alloys are presented. Calculated equilibrium lattice parameters deviate less than 1.2% from the experimental values. The main features of a half metallic system are present in the density of states for the PtMnSb and NiMnSb. We predict that PdMnSb shows half metallic character under hydrostatic pressure. The substitution of Sb in PtMnSb by Sn or Te destroys the minority spin band gap. Spin and orbital magnetic moments for all the systems are in good agreement with previous calculations and experimental data. L-2,L-3 x-ray absorption and x-ray magnetic circular dichroism (XMCD) spectra are calculated for all the five compounds. Pt spectra present big deviations from system to system in the PtMnY (Y=Sn,Sb,Te) compounds while Mn spectra show only small deviations. For all these spectra GGA underestimates the L-3/L-2 integrated branching ratio and produces a much smaller L-2 peak intensity for the Ni site in NiMnSb. The XMCD sum rules are used to compute the spin and orbital magnetic moments and the results are compared to the direct calculations. C1 IPCMS, GEMME, F-67037 Strasbourg, France. Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87544 USA. RP IPCMS, GEMME, 23 Rue du Loess, F-67037 Strasbourg, France. RI Alouani, Mebarek/A-9101-2011; Galanakis, Iosif/E-7969-2013 OI Alouani, Mebarek/0000-0002-7985-5276; NR 51 TC 72 Z9 72 U1 1 U2 16 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 FEB 1 PY 2000 VL 61 IS 6 BP 4093 EP 4102 DI 10.1103/PhysRevB.61.4093 PG 10 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700052 ER PT J AU L'abbe, C Coussement, R Odeurs, J Alp, EE Sturhahn, W Toellner, TS Johnson, C AF L'abbe, C Coussement, R Odeurs, J Alp, EE Sturhahn, W Toellner, TS Johnson, C TI Experimental demonstration of time-integrated synchrotron-radiation spectroscopy with crossed polarizer and analyzer SO PHYSICAL REVIEW B LA English DT Article ID NUCLEAR RESONANT SCATTERING; DIFFRACTION; MULTILAYER AB We present the results of a successful experiment performed with time-integrated synchrotron-radiation spectroscopy, a technique for studying hyperfine interactions. The measurement was performed on an enriched Fe sample in combination with a stainless-steel reference. A crossed polarizer/analyzer was used to reduce the prompt count rate. Time-integrated synchrotron-radiation spectroscopy is compared to the existing time differential synchrotron-radiation spectroscopy. The use of the polarizer/analyzer setup is discussed. Possible applications of time-integrated synchrotron-radiation spectroscopy are mentioned. C1 Katholieke Univ Leuven, Inst Kern Stralingsfys, B-3001 Louvain, Belgium. Argonne Natl Lab, Argonne, IL 60439 USA. RP L'abbe, C (reprint author), Katholieke Univ Leuven, Inst Kern Stralingsfys, Celestijnenlaan 200D, B-3001 Louvain, Belgium. NR 22 TC 11 Z9 11 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 FEB 1 PY 2000 VL 61 IS 6 BP 4181 EP 4185 DI 10.1103/PhysRevB.61.4181 PG 5 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700063 ER PT J AU Hart, GLW Pickett, WE Kurmaev, EZ Hartmann, D Neumann, M Moewes, A Ederer, DL Endoh, R Taniguchi, K Nagata, S AF Hart, GLW Pickett, WE Kurmaev, EZ Hartmann, D Neumann, M Moewes, A Ederer, DL Endoh, R Taniguchi, K Nagata, S TI Electronic structure of Cu1-xNixRh2S4 and CuRh2Se4: Band-structure calculations, x-ray photoemission, and fluorescence measurements SO PHYSICAL REVIEW B LA English DT Article ID METAL-INSULATOR-TRANSITION; THIOSPINEL CUIR2S4; SPINEL COMPOUNDS; SUPERCONDUCTIVITY AB The electronic structure of spinel-type Cu1-xNixRh2S4 (x = 0.0, 0.1, 0.3, 0.5, 1.0) and CuRh2Se4 compounds has been studied by means of x-ray photoelectron (XPS) and fluorescent spectroscopy. Cu L-3, Ni L-3, S L-2,L-3, and Se M-2,M-3 x-ray emission spectra (XES) were measured near thresholds at Beamline 8.0 of the Lawrence Berkeley Laboratory's Advanced Light Source. XES measurements of the constituent atoms of these compounds, reduced to the same binding energy scale, are found to be in excellent agreement with XPS valence bands. The calculated XES spectra which include dipole matrix elements show that the partial density of states reproduce experimental spectra quite well. States near the Fermi level (E-F) have strong Rh d and S(Se) p character in all compounds. In NiRh2S4 the Ni 3d states contribute strongly at E-F, whereas in both Cu compounds the Cu 3d bands are only similar to 1 eV wide and centered similar to 2.5 eV below E-F, leaving very little 3d character at E-F. The density of stares at the Fermi level is less in NiRh2S4 than in CuRh2S4. This difference may contribute to the observed decrease, as a function of Ni concentration, in the superconducting transition temperature in Cu1-xNixRh2S4. The density of states of the ordered alloy Cu0.5Ni0.5Rh2S4 shows behavior that is more "split-band"-like than "rigid-band"-like. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Russian Acad Sci, Inst Met Phys, Ural Div, Yekaterinburg 620219, Russia. Univ Osnabruck, Dept Phys, D-49069 Osnabruck, Germany. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70803 USA. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Muroran Inst Technol, Dept Mat Sci & Engn, Muroran, Hokkaido 0508585, Japan. RP Hart, GLW (reprint author), Nat Renewable Energy Lab, Golden, CO 80401 USA. EM ghart@nrel.gov RI Kurmaev, Ernst/J-4254-2013; OI Kurmaev, Ernst/0000-0003-4625-4930; Hart, Gus L. W./0000-0002-6149-9234 NR 35 TC 11 Z9 11 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 2000 VL 61 IS 6 BP 4230 EP 4237 DI 10.1103/PhysRevB.61.4230 PG 8 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700071 ER PT J AU Matsuda, M Lee, YS Greven, M Kastner, MA Birgeneau, RJ Yamada, K Endoh, Y Boni, P Lee, SJ Wakimoto, S Shirane, G AF Matsuda, M Lee, YS Greven, M Kastner, MA Birgeneau, RJ Yamada, K Endoh, Y Boni, P Lee, SJ Wakimoto, S Shirane, G TI Freezing of anisotropic spin clusters in La1.98Sr0.02CuO4 SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; LA2CUO4; MODEL AB A spin-glass compound, La1.98Sr0.02CuO4, shows quasi-three-dimensional magnetic ordering below similar to 40 K. A remarkable feature is that the magnetic correlation length along the orthorhombic a(ortho) axis is much longer than that along the b(ortho) axis, suggesting that the spin structure is closely related to the diagonal stripe structure. The spin-glass state can be expressed as a random freezing of quasi-three-dimensional spin clusters with anisotropic spin correlations (xi(a)'similar to 160 Angstrom, xi(b)'similar to 25 Angstrom, and xi(c)'similar to 4.7 Angstrom at 1.6 K). The new magnetic state is important as an intermediate phase between the three-dimensional antiferromagnetic ordered phase in La2CuO4 and the incommensurate phase in La1.95Sr0.05CuO4 in which the positions of the incommensurate peaks are rotated by 45 degrees in reciprocal space about (pi, pi) from those observed in the superconducting La2CuO4 compounds. C1 RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 9800812, Japan. PSI, Neutron Scattering Lab, CH-5232 Villigen, Switzerland. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Matsuda, M (reprint author), RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. RI Yamada, Kazuyoshi/C-2728-2009; Matsuda, Masaaki/A-6902-2016 OI Matsuda, Masaaki/0000-0003-2209-9526 NR 19 TC 33 Z9 33 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 FEB 1 PY 2000 VL 61 IS 6 BP 4326 EP 4333 DI 10.1103/PhysRevB.61.4326 PG 8 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700083 ER PT J AU Bulaevskii, LN Koshelev, AE Vinokur, VM Maley, MP AF Bulaevskii, LN Koshelev, AE Vinokur, VM Maley, MP TI Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors SO PHYSICAL REVIEW B LA English DT Article ID JOSEPHSON-COUPLED SUPERCONDUCTORS; VORTICES; LIQUID; PHASE AB We consider the magnetic-field dependence of the plasma resonance frequency in pristine and in irradiated Bi2Sr2CaCu2O8 crystals near T-c. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near T-c and (ii) at small melting fields (<20 G) the wandering length does not change much at the melting transition. This shows existence of the line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near T-c. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Bulaevskii, LN (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 15 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 FEB 1 PY 2000 VL 61 IS 6 BP R3819 EP R3822 DI 10.1103/PhysRevB.61.R3819 PG 4 WC Physics, Condensed Matter SC Physics GA 285AH UT WOS:000085364700016 ER PT J AU Blanpied, G Blecher, M Caracappa, A Djalali, C Duval, MA Giordano, G Hicks, K Hoblit, S Khandaker, M Kistner, OC Matone, G Miceli, L Mize, WK Molinari, C Preedom, BM Sandorfi, AM Schaerf, C Sealock, RM Rebreyend, D Thorn, CE Thornton, ST Viziri, K Whisnant, CS Zhao, X AF Blanpied, G Blecher, M Caracappa, A Djalali, C Duval, MA Giordano, G Hicks, K Hoblit, S Khandaker, M Kistner, OC Matone, G Miceli, L Mize, WK Molinari, C Preedom, BM Sandorfi, AM Schaerf, C Sealock, RM Rebreyend, D Thorn, CE Thornton, ST Viziri, K Whisnant, CS Zhao, X CA LEGS Collaboration TI Measurement of H-2((gamma)over-right-arrow,p)n with linearly polarized photons in the Delta resonance region SO PHYSICAL REVIEW C LA English DT Article ID DIFFERENTIAL CROSS-SECTION; D-STATE PROBABILITY; DEUTERON PHOTODISINTEGRATION; INTERMEDIATE ENERGIES; PI-THRESHOLD; H-2(GAMMA,P)N; OBSERVABLES; SYSTEMS; FREEDOM; NN AB The photodisintegration of deuterium with linearly polarized light has been measured in the energy range of 110-315 MeV. The results of five independent measurements using three detector systems, two liquid target,geometries, and two photon energy distribution end points are presented. These data are combined into one average data set with a systematic uncertainty of +/-5%. The statistical precision of this combined data set, coupled with the sensitivity to the strength of the shea range tensor interaction observed in the parallel-perpendicular cross section difference, makes this an attractive reaction for investigating aspects of the NN interaction. To do this reliably requires a complete, systematic description of the reaction through the Delta region. Recent NN-N Delta coupled-channel calculations which include fully retarded pion potentials are compared with multipole fits to the data. These calculations cannot reproduce the energy and angle dependence of the data. The character of the disagreement suggests that the remaining problems may lie with the treatment of the Delta. C1 Univ S Carolina, Dept Phys, Columbia, SC 29208 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Roma Tor Vergata, Rome, Italy. Ist Nazl Fis Nucl, Sez Roma 2, Rome, Italy. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. Ohio Univ, Dept Phys, Athens, OH 45701 USA. Inst Sci Nucl Grenoble, F-38026 Grenoble, France. Univ Genoa, I-16146 Genoa, Italy. Ist Nazl Fis Nucl, Sez Genova, I-16146 Genoa, Italy. Norfolk State Univ, Dept Phys, Norfolk, VA 23504 USA. Rensselaer Polytech Inst, Dept Phys, Troy, NY 12180 USA. RP Univ S Carolina, Dept Phys, Columbia, SC 29208 USA. EM whisnant@sc.edu NR 41 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 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 024604 PG 25 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800040 ER PT J AU Blundell, HG Godfrey, S Hay, G Swanson, ES AF Blundell, HG Godfrey, S Hay, G Swanson, ES TI A quark model calculation of gamma gamma ->pi pi including final-state interactions SO PHYSICAL REVIEW C LA English DT Article ID PHOTON-PHOTON COLLISIONS; PION; CHROMODYNAMICS; SCATTERING; MESONS AB A quark model calculation of the processes gamma gamma --> pi(+) pi(-) and gamma gamma --> pi(0) pi(0) is performed. At tree level, only charged pions couple to the initial state photons and neutral pions are not expected in the final state. However, a small but significant gamma gamma --> pi(0) pi(0) cross section is observed. We demonstrate that this may be accounted for by a rotation in isospin space induced by final-state interactions. The resulting pi(+) pi(-) cross section is In good agreement with experiment; while the pi(0) pi(0) cross section is in qualitative agreement with the data. C1 Carleton Univ, Dept Phys, Ottawa Carleton Inst Phys, Ottawa, ON K1S 5B6, Canada. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Blundell, HG (reprint author), Carleton Univ, Dept Phys, Ottawa Carleton Inst Phys, Ottawa, ON K1S 5B6, Canada. NR 36 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 025203 DI 10.1103/PhysRevC.61.025203 PG 7 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800062 ER PT J AU Brachmann, J Soff, S Dumitru, A Stocker, A Maruhn, JA Greiner, W Bravina, LV Rischke, DH AF Brachmann, J Soff, S Dumitru, A Stocker, A Maruhn, JA Greiner, W Bravina, LV Rischke, DH TI Antiflow of nucleons at the softest point of the equation of state SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; GLUON STRING MODEL; COLLECTIVE FLOW; ELLIPTIC FLOW; AU+AU COLLISIONS; PHASE-TRANSITION; ENERGY; DISAPPEARANCE; HYDRODYNAMICS; SIGNATURE AB We investigate flow in semiperipheral nuclear collisions at Alternating Gradient Synchrotron and Super Proton Synchrotron energies within macroscopic as well as microscopic transport models. The hot and dense zone assumes the shape of an ellipsoid which is tilted by an angle Theta with respect to the beam axis. If matter is close to the softest point of the equation of slate, this ellipsoid expands predominantly orthogonal to the direction given by Theta. This antiflow component is responsible for the previously predicted reduction of the directed transverse momentum around the softest point of the equation of state. C1 Univ Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, Germany. Moscow State Univ, Inst Nucl Phys, RU-119899 Moscow, Russia. Brookhaven Natl Lab, RIKEN, BNL Res Ctr, Upton, NY 11973 USA. RP Bravina, LV (reprint author), Univ Frankfurt, Inst Theoret Phys, Postfach 111932, D-60054 Frankfurt, Germany. NR 45 TC 114 Z9 115 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 024909 DI 10.1103/PhysRevC.61.024909 PG 8 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800058 ER PT J AU Dioszegi, I Shaw, NP Mazumdar, I Hatzikoutelis, A Paul, P AF Dioszegi, I Shaw, NP Mazumdar, I Hatzikoutelis, A Paul, P TI Nuclear viscosity of hot rotating Th-224 SO PHYSICAL REVIEW C LA English DT Article ID GIANT-DIPOLE-RESONANCE; LEVEL DENSITY PARAMETER; HEAVY-ION REACTIONS; TEMPERATURE-DEPENDENCE; INDUCED FISSION; ANGULAR-DISTRIBUTIONS; BAF2 SCINTILLATION; ELASTIC-SCATTERING; DIFFUSION PROCESS; NEUTRON EMISSION AB In a detailed investigation of giant dipole resonance (GDR) gamma-ray yield from the O-16+Pb-208 system, the absolute gamma-ray/fission multiplicities are extracted and reported over a wide range of excitation energy and angular momentum. The enhanced yield of GDR decay gamma rays from the compound system has been analyzed within the framework of a modified statistical model containing the nuclear viscosity as a foe parameter. The nuclear viscosity parameter gamma has been studied over a much wider range of excitation energy and angular momentum than in earlier works. The measured gamma-ray multiplicities as well as known neutron multiplicities and evaporation residue cross sections indicate a strongly damped fission motion. The systematics of the extracted dissipation coefficient is fitted equally well with either temperature or a deformation-dependent nuclear viscosity. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. NR 82 TC 89 Z9 89 U1 2 U2 5 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 FEB PY 2000 VL 61 IS 2 AR 024613 DI 10.1103/PhysRevC.61.024613 PG 17 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800049 ER PT J AU Djerroud, B Schaly, B Flibotte, S Ball, GC Courtin, S Cromaz, M Haslip, DS Lampman, T Macchiavelli, AO Nieminen, JM Svensson, CE Waddington, JC Ward, D Wilson, JN AF Djerroud, B Schaly, B Flibotte, S Ball, GC Courtin, S Cromaz, M Haslip, DS Lampman, T Macchiavelli, AO Nieminen, JM Svensson, CE Waddington, JC Ward, D Wilson, JN TI Fission barriers, coupled-channel, and shell effects at the Coulomb barrier in the A similar to 190 mass region SO PHYSICAL REVIEW C LA English DT Article ID INDUCED NUCLEAR-FISSION; GROUND-STATE MASSES; ENTRANCE-CHANNEL; SUPERDEFORMED BANDS; SCALING LAWS; FUSION; POPULATION; MODEL; PROBABILITIES; DEFORMATIONS AB A study of the role of coupled-channel effects in the enhancement of the population of high-spin states was undertaken with the reactions Ca-48+Nd-142 and Se-80+Pd-110, near the Coulomb barrier, leading to the same compound nucleus, Hg-190, at the same excitation energy. Statistical calculations with standard values for the level density parameters and fission barriers predict an enhancement of the high-spin population for the more mass-symmetric system, brought about by the coupling to inelastic channels in the fusion process. No enhancement was observed which we interpret as an inadequacy of the fission barriers used, and to the role of the shell corrections, in particular those at the saddle point. C1 McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. TRIUMF, Vancouver, BC V6T 2A3, Canada. Inst Rech Subatom, F-67037 Strasbourg, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. RP Djerroud, B (reprint author), McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. NR 42 TC 4 Z9 4 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 FEB PY 2000 VL 61 IS 2 AR 024607 DI 10.1103/PhysRevC.61.024607 PG 7 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800043 ER PT J AU Ghugre, SS Kharraja, B Garg, U Janssens, RVF Carpenter, MP Crowell, B Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R AF Ghugre, SS Kharraja, B Garg, U Janssens, RVF Carpenter, MP Crowell, B Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R TI Level structure of Tc-94,Tc-95,Tc-96 at high spins and shell-model calculations SO PHYSICAL REVIEW C LA English DT Article ID STATES AB High-spin states in the Tc-94,Tc-95,Tc-96 (N = 51, 52, and 53) nuclei have been investigated using the Cu-65 + S-36 reaction at a beam energy of 142 MeV. More than 60 new transitions have been identified and placed in their level schemes, which now extend up to spin J approximate to 22 (h) over bar and excitation energies E-x approximate to 12 MeV. Spherical shell-model calculations have been performed using different model spaces. A restricted model space, using Sr-88 as the core and the pi(p(1/2), g(9/2)) nu(d(5/2), s(1/2)) valence orbitals, reproduces the experimental excitation energies up to J approximate to 14 (h) over bar. The higher-angular-momentum states are dominated by the excitation of a g(9/2) neutron across the N = 50 magic core, as indicated by large-basis shell model calculations. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Soltan Inst Nucl Studies, PL-05400 Swierk, Poland. RP Ghugre, SS (reprint author), IUCDAEF Calcutta Ctr, Sector IIILB8, Bidhan Nagar, Calcutta 700091, W Bengal, India. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 18 TC 5 Z9 5 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 FEB PY 2000 VL 61 IS 2 AR 024302 PG 9 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800019 ER PT J AU Hardtke, D Voloshin, SA AF Hardtke, D Voloshin, SA TI Relationship between particle freeze-out distributions and Hanbury Brown-Twiss radius parameters SO PHYSICAL REVIEW C LA English DT Article ID QUANTUM MOLECULAR-DYNAMICS; COLLISIONS AB The relationship between pion and kaon space-time freeze-out distributions and the Hanbury Brown-Twiss (HBT) radius parameters in high-energy nucleus-nucleus collisions is investigated. We show that the HBT radius parameters in general do not reflect the rms deviations of the single particle production points. Instead, the HBT radius parameters are most closely related to the curvature of the two-particle space-time relative position distribution at the origin. We support our arguments by studies with a dynamical model (RQMD 2.4). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Wayne State Univ, Dept Phys & Astron, Detroit, MI 48201 USA. RP Hardtke, D (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Voloshin, Sergei/I-4122-2013 NR 9 TC 26 Z9 27 U1 0 U2 8 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 FEB PY 2000 VL 61 IS 2 AR 024905 DI 10.1103/PhysRevC.61.024905 PG 4 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800054 ER PT J AU Kharraja, B Garg, U Ghugre, SS Jin, H Janssens, RVF Ahmad, I Amro, H Carpenter, MP Fischer, S Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R Ruchowska, E Ma, WC Govil, IM AF Kharraja, B Garg, U Ghugre, SS Jin, H Janssens, RVF Ahmad, I Amro, H Carpenter, MP Fischer, S Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R Ruchowska, E Ma, WC Govil, IM TI Recoil-distance lifetime measurements in Ru-96,Ru-97,Ru-98: Search for possible onset of collectivity at N >= 52 SO PHYSICAL REVIEW C LA English DT Article ID SHELL-MODEL; HIGH SPINS; SPECTROSCOPY AB Lifetimes of high-spin states in the N=52-54 Ru nuclei have been investigated via the Cu-65(S-36, pyn) Ru-96,Ru-97,Ru-98 (y = 4,3,2) reactions using the recoil-distance Doppler-shift technique. The data were collected in coincidence mode. Lifetimes have been extracted for both the positive- and the negative-parity states in Ru-96 and Ru-98 and for the positive-parity states in Ru-97. The levels studied have lifetimes in the range 2-31 ps. The observed reduced transition probabilities B(E2) and B(M1) are compared with the predictions of the shell model. Theoretical implications of these results are discussed. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Soltan Inst Nucl Studies, PL-05400 Swierk, Poland. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Panjab Univ, Dept Phys, Chandigarh 160014, India. RP Kharraja, B (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 15 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 024301 PG 7 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800018 ER PT J AU Khaustov, P Alburger, DE Barnes, PD Bassalleck, B Berdoz, AR Biglan, A Burger, T Carman, DS Chrien, RE Davis, CA Fischer, H Franklin, GB Franz, J Gan, L Ichikawa, A Iijima, T Imai, K Kondo, Y Koran, P Landry, M Lee, L Lowe, J Magahiz, R May, M McCrady, R Meyer, CA Merrill, F Page, SA Paschke, K Pile, PH Quinn, B Ramsay, WD Rusek, A Sawafta, R Schmitt, H Schumacher, RA Stotzer, RW Sutter, R Takeutchi, F van Oers, WTH Yamamoto, K Yosoi, M Zeps, VJ AF Khaustov, P Alburger, DE Barnes, PD Bassalleck, B Berdoz, AR Biglan, A Burger, T Carman, DS Chrien, RE Davis, CA Fischer, H Franklin, GB Franz, J Gan, L Ichikawa, A Iijima, T Imai, K Kondo, Y Koran, P Landry, M Lee, L Lowe, J Magahiz, R May, M McCrady, R Meyer, CA Merrill, F Page, SA Paschke, K Pile, PH Quinn, B Ramsay, WD Rusek, A Sawafta, R Schmitt, H Schumacher, RA Stotzer, RW Sutter, R Takeutchi, F van Oers, WTH Yamamoto, K Yosoi, M Zeps, VJ CA AGS E885 Collaboration TI Search for double-Lambda hypernuclei formation via (Xi(-),C-12)(atom)-> B-12(Lambda Lambda)+n SO PHYSICAL REVIEW C LA English DT Article AB Measurement of the energy of neutrons in coincidence with the production of free Xi(-) hyperons can be used to determine the masses of B-12(Lambda Lambda) hypernuclear states and branching ratios of their formation from (Xi(-), C-12)(atom) --> B-12(Lambda Lambda)+n. The E885 Collaboration utilized the Alternating Gradient Synchrotron 1.8 GeV/c K- beam incident on a diamond target to accumulate the largest-to-date data sample of (K-,K+) events. A total of about 3x10(5) (K-,K+) events have been collected and analyzed. The neutron spectrum shows no apparent peaks from the neutron-emission channel of double-Lambda hypernuclear formation from (Xi(-), C-12)(atom) decay. The upper limit on the branching ratio of the above process has been set to be at or below 4% in the region of expected neutron energies. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 305, Japan. Kyoto Sangyo Univ, Kyoto 603, Japan. Kyoto Univ, Sakyo Ku, Kyoto 606, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Freiburg, D-79104 Freiburg, Germany. Univ Kentucky, Lexington, KY 40507 USA. Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. Univ New Mexico, Albuquerque, NM 87131 USA. RP Khaustov, P (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Schumacher, Reinhard/K-6455-2013; Meyer, Curtis/L-3488-2014 OI Schumacher, Reinhard/0000-0002-3860-1827; Meyer, Curtis/0000-0001-7599-3973 NR 16 TC 12 Z9 12 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 FEB PY 2000 VL 61 IS 2 AR 027601 DI 10.1103/PhysRevC.61.027601 PG 4 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800071 ER PT J AU Leviatan, A Ginocchio, JN AF Leviatan, A Ginocchio, JN TI F spin as a partial symmetry SO PHYSICAL REVIEW C LA English DT Article ID PARTIAL DYNAMICAL SYMMETRY; INTERACTING-BOSON MODEL; RARE-EARTH NUCLEI; EVEN-EVEN NUCLEI; PROTON; EXCITATIONS; SYSTEMATICS; SCATTERING; MULTIPLETS; STATES AB We use the empirical evidence that F-spin multiplets exist in nuclei for only selected states as an indication that F spin can be regarded as a partial symmetry. We show that there is a class of non-F-scalar IBM-2 Hamiltonians with partial F-spin symmetry, which reproduce the known systematics of collective bands in nuclei. These Hamiltonians predict that the scissors states have good F-spin and form F-spin multiplets, which is supported by the existing data. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. RP Leviatan, A (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NR 26 TC 17 Z9 17 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 024305 DI 10.1103/PhysRevC.61.024305 PG 4 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800022 ER PT J AU Nara, Y Otuka, H Ohnishi, A Niita, K Chiba, S AF Nara, Y Otuka, H Ohnishi, A Niita, K Chiba, S TI Relativistic nuclear collisions at 10A GeV energies from p+Be to Au+Au with the hadronic cascade model SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; STRANGE PARTICLE-PRODUCTION; CERN SPS; ULTRARELATIVISTIC ENERGIES; EVENT GENERATOR; PROTON-NUCLEUS; AA COLLISIONS; PARTON; FLOW; DYNAMICS AB A hadronic cascade model based on resonances and strings is used to study mass dependence of relativistic nuclear collisions from p + Be to Au+Au at AGS energies (similar to 10A GeV) systematically. Hadron transverse momentum and rapidity distributions obtained with both cascade calculations and Glauber-type calculations are compared with experimental data, leading to a detailed discussion concerning the importance of rescattering among hadrons. We find good agreement with the experimental data without ally change of model parameters with the cascade model. It is found that rescattering is of importance both for the explanation of the high transverse momentum tail and for the multiplicity of produced particles. C1 Japan Atom Energy Res Inst, Adv Sci Res Ctr, Naka Ku, Tokai, Ibaraki 3191195, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Hokkaido Univ, Grad Sch Sci, Div Phys, Sapporo, Hokkaido 0600810, Japan. Res Org Informat Sci & Technol, Naka Ku, Tokai, Ibaraki 3191195, Japan. RP Japan Atom Energy Res Inst, Adv Sci Res Ctr, Naka Ku, Tokai, Ibaraki 3191195, Japan. RI Ohnishi, Akira/F-7403-2011; Chiba, Satoshi/E-8193-2014 OI Ohnishi, Akira/0000-0003-1513-0468; NR 69 TC 150 Z9 151 U1 0 U2 2 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 FEB PY 2000 VL 61 IS 2 AR 024901 PG 19 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800050 ER PT J AU Payne, GL Glockle, W Friar, JL AF Payne, GL Glockle, W Friar, JL TI Boundary conditions for three-body scattering in configuration space SO PHYSICAL REVIEW C LA English DT Article ID BREAKUP AB The asymptotic behavior of three-body scattering wave functions in configuration space is studied by considering a model equation that has the same asymptotic form as the Faddeev equations. Boundary conditions for the wave function are derived, and their validity is verified by numerical calculations. It is shown that these boundary conditions for the partial differential equation can be used to obtain accurate numerical solutions for the wave function. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Ruhr Univ Bochum, Inst Theoret Phys 2, D-4630 Bochum, Germany. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Payne, GL (reprint author), Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. NR 8 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 FEB PY 2000 VL 61 IS 2 AR 024005 DI 10.1103/PhysRevC.61.024005 PG 9 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800017 ER PT J AU Petersen, TC Randrup, J AF Petersen, TC Randrup, J TI Dynamical simulation of disoriented chiral condensate formation in Bjorken rods SO PHYSICAL REVIEW C LA English DT Article ID HIGH-ENERGY COLLISIONS; QUARK-GLUON PLASMA; LINEAR SIGMA-MODEL; PHASE-TRANSITION; NUCLEAR COLLISIONS; DCC; FIELD; EVOLUTION; DOMAINS; FORM AB Using a semiclassical treatment of the linear a model, we simulate the dynamical evolution of an initially hot cylindrical rod endowed with a longitudinal Bjorken scaling expansion (a "Bjorken rod"). The field equation is propagated until full decoupling has occurred and the asymptotic many-body state of free pions is then obtained by a suitable Fourier decomposition of the held and a subsequent stochastic determination of the number of quanta in each elementary mode. The resulting transverse pion spectrum exhibits visible enhancements below 200 MeV due to the parametric amplification caused by the oscillatory relaxation of the chiral order parameter. Ensembles of such final states are subjected to various event-by-event analyses. The factorial moments of the multiplicity distribution suggest that the soft pions are nonstatistical. Furthermore, their emission patterns exhibit azimuthal correlations that have a bearing on the domain size in the source. Finally, the distribution of the neutral pion fraction shows a significant broadening for the soft pions which grows steadily as the number of azimuthal segments is increased. All of these features are indicative of disoriented chiral condensates and it may be interesting to apply similar analyses to actual data from high-energy nuclear collision experiments. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 39 TC 18 Z9 18 U1 1 U2 1 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 FEB PY 2000 VL 61 IS 2 AR 024906 DI 10.1103/PhysRevC.61.024906 PG 16 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800055 ER PT J AU Prendergast, EP van den Brink, A de Haas, AP Kamermans, R Kuijer, PG de Laat, CTAM Ostendorf, RW Oti, E Peghaire, A Snellings, RJM AF Prendergast, EP van den Brink, A de Haas, AP Kamermans, R Kuijer, PG de Laat, CTAM Ostendorf, RW Oti, E Peghaire, A Snellings, RJM TI Flow and multifragmentation of Mg-24+Al-27 at intermediate energies SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; AZIMUTHAL CORRELATION-FUNCTIONS; NUCLEUS-NUCLEUS COLLISIONS; COLLECTIVE MOTION; ANGULAR-CORRELATIONS; REACTION DYNAMICS; IMPACT-PARAMETER; DISTRIBUTIONS; DISAPPEARANCE; REDUCIBILITY AB An elaborated investigation was done into the reaction mechanism of heavy ion collisions at intermediate energies of small nuclear systems. Experimental data measured with the Huygens detectors and isospin quantum molecular dynamics (IQMD) simulations of Mg-24+Al-27 at 45 and 95A MeV were analyzed with respect to the impact-parameter selection, the in-plane flow and the IMF production at midrapidity. It was found that only the midcentral impact-parameter class could be identified effectively. The event-plane reconstruction and flow measurements were studied with IQMD and a GEANT detector simulation. This showed that the azimuthal-correlation method gives the best reconstruction. The experimentally measured in-plane flow was consistent with the balancing energy derived from literature of 114+/- 10A MeV. The azimuthal correlations and polar-angle distributions of IMF's emitted at midrapidity were used to distinguish between a dynamic scenario, i.e., IQMD, and a statistical scenario described by a simple decaying-source model. The IQMD simulations were in good agreement with the experimental data while a single decaying-source simulation fails to describe the data which shows that multifragmentation in these small systems is consistent with a dynamic process. C1 Univ Utrecht, NIKHEF, NL-3508 TA Utrecht, Netherlands. Kernfys Versneller Inst, NL-9747 AA Groningen, Netherlands. GANIL, F-14021 Caen, France. LBNL, Berkeley, CA 94720 USA. RP Prendergast, EP (reprint author), Univ Utrecht, NIKHEF, POB 80-000, NL-3508 TA Utrecht, Netherlands. NR 48 TC 3 Z9 5 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 FEB PY 2000 VL 61 IS 2 AR 024611 DI 10.1103/PhysRevC.61.024611 PG 9 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800047 ER PT J AU Sharapov, EI Bowman, JD Crawford, BE Delheij, PPJ Frankle, CM Iinuma, M Knudson, JN Lowie, LY Lynch, JE Masaike, A Matsuda, Y Mitchell, GE Penttila, SI Postma, H Roberson, NR Seestrom, SJ Stephenson, SL Yen, YF Yuan, VW AF Sharapov, EI Bowman, JD Crawford, BE Delheij, PPJ Frankle, CM Iinuma, M Knudson, JN Lowie, LY Lynch, JE Masaike, A Matsuda, Y Mitchell, GE Penttila, SI Postma, H Roberson, NR Seestrom, SJ Stephenson, SL Yen, YF Yuan, VW TI Parity violation in Th-232 neutron resonances above 250 eV SO PHYSICAL REVIEW C LA English DT Article ID NONCONSERVATION; STATES AB The analysis of parity nonconservation (PNC) measurements performed on Th-232 by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar analysis was performed on the data below 250 eV, for which longitudinal asymmetries were obtained previously. For energies below 250 eV, the p-wave neutron strength functions for the J = 1/2 and J = 3/2 states were extracted: S-1/2(1) = (1.68 +/-i 0.61) x 10(-4) and S-3/2(1) = (0.75 +/- 0.18) x 10(-4). The data provide constraints on the properties of local doorway states proposed to explain the PNC sign effect in thorium. C1 Joint Inst Nucl Res, Dubna 141980, Russia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Duke Univ, Durham, NC 27708 USA. Triangle Univ Nucl Lab, Durham, NC 27708 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Kyoto Univ, Dept Phys, Kyoto 60601, Japan. N Carolina State Univ, Raleigh, NC 27695 USA. Gettysburg Coll, Gettysburg, PA 17325 USA. Delft Univ Technol, NL-2600 GA Delft, Netherlands. RP Joint Inst Nucl Res, Dubna 141980, Russia. RI Matsuda, Yasuyuki/C-3007-2008 OI Matsuda, Yasuyuki/0000-0002-9847-3791 NR 23 TC 7 Z9 7 U1 0 U2 1 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 FEB PY 2000 VL 61 IS 2 AR 025501 DI 10.1103/PhysRevC.61.025501 PG 7 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800066 ER PT J AU Wang, FQ Xu, N AF Wang, FQ Xu, N TI Baryon phase-space density in heavy-ion collisions SO PHYSICAL REVIEW C LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; PB+PB COLLISIONS; SOURCE SIZE; PION INTERFEROMETRY; CERN SPS; DEPENDENCE; EXPANSION; THERMODYNAMICS; EQUILIBRATION; ENERGIES AB The baryon phase-space density at mid-rapidity from central heavy-ion collisions is estimated from proton spectra with interferometry and deuteron coalescence measurements. It is found that the mid-rapidity phase-space density of baryons is significantly lower at the super proton synchrotron than the Alternating-Gradient Synchrotron, while those of total particles (pion + baryon) are comparable. Thermal and chemical equilibrium model calculations tend to over-estimate the phase-space densities at both energies. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 47 TC 11 Z9 11 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 FEB PY 2000 VL 61 IS 2 AR 021904 DI 10.1103/PhysRevC.61.021904 PG 4 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800012 ER PT J AU Wu, CY Cline, D Simon, MW Teng, R Vetter, K Carpenter, MP Janssens, RVF Wiedenhover, I AF Wu, CY Cline, D Simon, MW Teng, R Vetter, K Carpenter, MP Janssens, RVF Wiedenhover, I TI Complex band interactions in Er-170 SO PHYSICAL REVIEW C LA English DT Article ID STATES; EXCITATION AB Inelastic excitation of Er-170 by a U-238 beam, studied at near-barrier energies, has led to the observation of unusual features in rotational bands built on low-lying vibrations. The population of the high-spin members of the K pi = 0(+), beta-vibrational band is enhanced due to mixing with the K-pi = 2(+), gamma-vibrational band at spin 4(+). Strong mixing of the K-pi=0(+) band with a rotationally aligned 2 qp band results in this band losing its beta-vibrational character and in a rapid gain in spin alignment leading to a crossing with the ground-state band between spins 20(+) and 22(+). The low-lying K-pi = 3(+) band also is populated. It subsequently decays to both the gamma-vibrational and the ground-state bands. The occurrence of appreciable K-forbidden E2 transitions from the K-pi = 3(+) to the ground-state band is attributed to mixing with the K-pi=2(+) band, caused by the interaction between the quadrupole gamma-vibrational and the hexadecapole vibrational motions. C1 Univ Rochester, Nucl Struct Res Lab, Rochester, NY 14627 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Cline, D (reprint author), Univ Rochester, Nucl Struct Res Lab, Rochester, NY 14627 USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 21 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 2000 VL 61 IS 2 AR 021305 DI 10.1103/PhysRevC.61.021305 PG 5 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800005 ER PT J AU Wulf, EA Canon, RS Gaff, SJ Kelley, JH Prior, RM Schreiber, EC Spraker, M Tilley, DR Weller, HR Viviani, M Kievsky, A Rosati, S Schiavilla, R AF Wulf, EA Canon, RS Gaff, SJ Kelley, JH Prior, RM Schreiber, EC Spraker, M Tilley, DR Weller, HR Viviani, M Kievsky, A Rosati, S Schiavilla, R TI New photodisintegration threshold observable in He-3 SO PHYSICAL REVIEW C LA English DT Article ID HEARN SUM-RULE; RADIATIVE-CAPTURE; DEUTERON; SYSTEMS AB Measurements of the cross section. vector and tensor analyzing powers, and linear gamma-ray polarization in the radiative capture reactions D(p, gamma) He-3 and p(d, gamma)He-3 at c.m, energies in the range 0-53 keV allow the determination of the reduced matrix elements (RMEs) relevant for these transitions. From these RMEs the value of the integral which determines the Gerasimov-Drell-Hearn sum rule for He-3 is obtained in the threshold region, corresponding to two-body breakup, and compared with the results of an ab initio microscopic three-body model calculation. The theoretical predictions for the value of this integral based on a "nucleons-only" assumption are an order of magnitude smaller than experiment. The discrepancy is reduced to about a factor of 2 when two-body currents are taken into account. This factor of 2 is due to an almost exact cancellation between the dominant E1 RMEs in the theoretical calculation. The excess E1 strength observed experimentally could provide useful insights into the nuclear interaction at low energies. C1 Duke Univ, Dept Phys, Durham, NC 27708 USA. Triangle Univ Nucl Lab, Durham, NC 27708 USA. N Georgia Coll & State Univ, Dept Phys, Dahlonega, GA 30597 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27696 USA. Ist Nazl Fis Nucl, Sez Pisa, I-56100 Pisa, Italy. Univ Pisa, Dept Phys, I-56100 Pisa, Italy. Jefferson Lab, Newport News, VA 23606 USA. Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. RP Wulf, EA (reprint author), Duke Univ, Dept Phys, Durham, NC 27708 USA. RI kievsky, alejandro/A-7123-2011; Wulf, Eric/B-1240-2012 NR 20 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 FEB PY 2000 VL 61 IS 2 AR 021601 PG 4 WC Physics, Nuclear SC Physics GA 283WJ UT WOS:000085298800006 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsey, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evans, H Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Green, JA Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hays, C Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Knuteson, B Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kubantsev, M Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lucotte, A Lueking, L Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Martin, RD Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reay, NW Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Sidwell, RA Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Stanton, NR Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Toback, D Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wah, HD Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Wood, DR Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsey, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evans, H Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Green, JA Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hays, C Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Knuteson, B Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kubantsev, M Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lucotte, A Lueking, L Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Martin, RD Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reay, NW Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Sidwell, RA Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Stanton, NR Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Toback, D Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wah, HD Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Wood, DR Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A CA DO Collaboration TI Measurement of the inclusive differential cross section for Z bosons as a function of transverse momentum in (p) over-barp collisions at root s=1.8 TeV SO PHYSICAL REVIEW D LA English DT Article ID = 1.8 TEV; W-BOSON; PBARP COLLISIONS; LEPTON PAIRS; MONTE-CARLO; MASS; DISTRIBUTIONS; COLLIDERS; ENERGY; QCD AB We present a measurement of the differential cross section as a function of transverse momentum of the Z boson in collisions at root s = 1.8 TeV using data collected by the DO experiment at the Fermilab Tevatron Collider during 1994-1996. We find good agreement between our data and the next-to-next-to-next-leading-logarithmic resummation prediction and extract values of the non-perturbative parameters for the resummed prediction from a fit to the differential cross section. C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Inst High Energy Phys, Beijing 100039, Peoples R China. Univ Los Andes, Bogota, Colombia. Univ San Francisco Quito, Quito, Ecuador. Univ Grenoble 1, Inst Sci Nucl, CNRS, IN2P3, Grenoble, France. CEA, Serv Phys Particules, DAPNIA, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Lancaster, Lancaster, England. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Kansas State Univ, Manhattan, KS 66506 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), NYU, New York, NY 10003 USA. RI Shivpuri, R K/A-5848-2010; Chekulaev, Sergey/O-1145-2015; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Kim, Sun Kee/G-2042-2015; Sznajder, Andre/L-1621-2016 OI Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; Belyaev, Alexander/0000-0002-1733-4408; Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108 NR 50 TC 45 Z9 45 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. 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Chiarelli, G Chiou, CN Chlebana, F Christofek, L Cropp, R Chu, ML Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Costanzo, D Couyoumtzelis, C Cronin-Hennessy, D Culbertson, R Dagenhart, D Daniels, T DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Feng, Z Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J F'ukui, Y Gadomski, S Galeotti, S Gallinaro, M Ganel, O Garcia-Sciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gold, M Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Green, C Groer, L Grosso-Pilcher, C Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hauser, J Hayashi, E Heinrich, J Heiss, A Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Huang, Z Huffman, BT Hughes, R Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Joshi, U Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kennedy, RD Kephart, R Kestenbaum, D Khazins, D Kikuchi, T Kim, BJ Kim, HS Kim, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korytov, A Kovacs, E Kowald, W Kroll, J Kruse, M Kuhlmann, SE Kuns, E Kurino, K Kuwabara, T Laasanen, AT Lami, S Lammel, S Lamoureux, JI Lancaster, M Lanzoni, M Latino, G LeCompte, T Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Long, O Loreti, M Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maksimovic, P Mangano, M Mariotti, M Marriner, JP Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, K McIntyre, P Melese, P Menguzzato, M Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Miyashita, S Moggi, N Moore, E Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pompos, A Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Reischl, M Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Saab, T Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semeria, F Shah, T Shapiro, MD Shaw, NM Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Sliwa, K Smith, C Snider, FD Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strohmer, R Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, J Suzuki, T Takahashi, T Takano, T Takashima, R Takikawa, K Tanaka, M Tannenbaum, B Tartarelli, F Taylor, W Tecchio, M Teng, PK Teramoto, Y Terashi, K Tether, S Theriot, D Thomas, TL Thurman-Keup, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Ukegawa, F Valls, J van den Brink, SC Vejcik, S Velev, G Volobouev, I Vidal, R Vilar, R Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Warburton, A Watanabe, T Watts, T Webb, R Wei, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Zanetti, A Zetti, F Zucchelli, S CA CDF Collaboration TI Measurement of b(b)over-bar rapidity correlations in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW D LA English DT Article ID = 1.8 TEV; CENTRAL TRACKING CHAMBER; SILICON VERTEX DETECTOR; BOTTOM-QUARK PRODUCTION; JET CROSS-SECTION; ELECTROMAGNETIC CALORIMETER; PARTON DISTRIBUTIONS; (P)OVER-BAR-P COLLISIONS; COLLIDER DETECTOR; HADRON-COLLISIONS AB We report the first direct measurement of rapidity correlations in collisions at root s=1.8 TeV. We select events with a high transverse momentum muon accompanied by a jet, and a second jet associated with a decay vertex displaced from the pp interaction vertex. Two independent samples are obtained corresponding to events with a forward (2.0<\eta\<2.6) or central (\eta\<0.6) muon. We measure the ratio of forward to central production to be 0.361 +/- 0.033( stat)(-0.031)(+0/015)(syst), in good agreement with the next-to-leading order QCD prediction 0.338(-0.097)(+0.014). C1 Natl Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Chicago, Chicago, IL 60637 USA. Duke Univ, Durham, NC 27708 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Cambridge, MA 02139 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Acad Sinica, Taipei 11530, Taiwan. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste Udine, Ist Nazl Fis Nucl, Trieste, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Abe, F (reprint author), Natl Lab High Energy Phys, 1-1 Oho, Tsukuba, Ibaraki 305, Japan. RI Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Introzzi, Gianluca/K-2497-2015; vilar, rocio/D-7454-2014 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Introzzi, Gianluca/0000-0002-1314-2580; NR 57 TC 5 Z9 5 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 FEB 1 PY 2000 VL 61 IS 3 AR 032001 PG 18 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600004 ER PT J AU Afanasev, A Carlson, CE Wahlquist, C AF Afanasev, A Carlson, CE Wahlquist, C TI Soft contributions to hard pion photoproduction SO PHYSICAL REVIEW D LA English DT Article ID TO-LEADING-ORDER; POLARIZED PARTON DISTRIBUTIONS; MESON PHOTOPRODUCTION; D/U RATIO; LARGE-X; NUCLEON; QUARK; COLLISIONS; SCATTERING; PHYSICS AB Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where perturbatively calculable processes dominate. Our soft process estimate is based on vector meson dominance and data based parametrisations of semiexclusive hadronic cross sections. We find that soft processes dominate in single pion photoproduction somewhat past 2 GeV transverse momentum at a few times 10 GeV incoming energy. The recent polarization asymmetry data are consistent with the perturbative asymmetry being diluted by polarization insensitive soft processes. Determining the polarized gluon distribution using hard pion photoproduction appears feasible with a few hundred GeV of incoming energy (in the target rest frame). C1 N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Coll William & Mary, Dept Phys, Nucl & Particle Theory Grp, Williamsburg, VA 23187 USA. RP Afanasev, A (reprint author), N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. NR 36 TC 15 Z9 15 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 FEB 1 PY 2000 VL 61 IS 3 AR 034014 DI 10.1103/PhysRevD.61.034014 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600034 ER PT J AU Arkani-Hamed, N Schmaltz, M AF Arkani-Hamed, N Schmaltz, M TI Hierarchies without symmetries from extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID DOMAIN-WALL; TEV; MILLIMETER; FERMIONS AB It is commonly thought that small couplings in a low-energy theory, such as those needed for the fermion mass hierarchy or proton stability, must originate from symmetries in a high-energy theory. We show that this expectation is violated in theories where the standard model fields are confined to a thick wall in extra dimensions, with the fermions "stuck" at different points in the wall. Couplings between them are then suppressed due to the exponentially small overlaps of their wave functions. This provides a framework for understanding both the fermion mass hierarchy and proton stability without imposing symmetries, but rather in terms of higher dimensional geography. A model independent prediction of this scenario is non-universal couplings of the standard model fermions to the ''Kaluza-Klein" excitations of the gauge fields. This allows a measurement of the fermion locations in the extra dimensions at the CERN LHC or NLC if the wall thickness is close to the TeV scale. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Arkani-Hamed, N (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM nima@slac.stanford.edu; schmaltz@slac.stanford.edu NR 28 TC 526 Z9 527 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 FEB 1 PY 2000 VL 61 IS 3 AR 033005 DI 10.1103/PhysRevD.61.033005 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600013 ER PT J AU Barbosa, RF Albuquerque, IF Bondar, NF Carrigan, R Chen, D Cooper, PS Dai, LS Denisov, AS Dobrovolsky, AC Dubbs, T Endler, AMF Escobar, CO Foucher, M Golovtsov, VL Gottschalk, H Gouffon, P Grachev, VT Khanzadeev, AV Kubantsev, MA Kuropatkin, NP Lach, J Langland, J Lang, PF Li, CZ Li, YS Luksys, M Mahon, JRP McCliment, E Morelos, A Newsom, C Maia, MCP Samsonov, VM Schegelsky, VA Shi, HZ Smith, VJ Tang, FU Terentyev, NK Timm, S Tkatch, II Uvarov, LN Vorobyov, AA Jie, Y Zhao, WH Zheng, SC Zhong, YY AF Barbosa, RF Albuquerque, IF Bondar, NF Carrigan, R Chen, D Cooper, PS Dai, LS Denisov, AS Dobrovolsky, AC Dubbs, T Endler, AMF Escobar, CO Foucher, M Golovtsov, VL Gottschalk, H Gouffon, P Grachev, VT Khanzadeev, AV Kubantsev, MA Kuropatkin, NP Lach, J Langland, J Lang, PF Li, CZ Li, YS Luksys, M Mahon, JRP McCliment, E Morelos, A Newsom, C Maia, MCP Samsonov, VM Schegelsky, VA Shi, HZ Smith, VJ Tang, FU Terentyev, NK Timm, S Tkatch, II Uvarov, LN Vorobyov, AA Jie, Y Zhao, WH Zheng, SC Zhong, YY TI Measurement of the (Sigma)over-bar(-) lifetime and direct comparison with the Sigma(+) lifetime SO PHYSICAL REVIEW D LA English DT Article ID ASYMMETRY PARAMETER; BRANCHING RATIO; RADIATIVE DECAY AB We have measured the lifetime of the <(Sigma)over bar>(-) using the Fermilab, Proton Center 375 GeV/c charged hyperon beam. We obtained (80.43+/-0.80+/-0.14) ps. We also measured the lifetime of the Sigma(+), obtaining (80.38 +/-0.40+/-0.14) ps, in agreement with the Particle Data Group value. A direct comparison between the two lifetimes from the ratio of the decay curves gives a fractional lifetime difference of Delta tau/<(tau)over bar>=(-0.06+/-1.12)%, consistent with equal lifetimes for baryon and antibaryon as required by CPT invariance. C1 Univ Sao Paulo, Inst Fis, BR-05508 Sao Paulo, Brazil. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Petersburg Nucl Phys Inst, Gatchina, Russia. Inst High Energy Phys, Beijing 100039, Peoples R China. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Iowa, Iowa City, IA 52242 USA. Inst Theoret & Expt Phys, Moscow 117259, Russia. SUNY Albany, Albany, NY 12222 USA. Univ Fed Paraiba, BR-58059900 Joao Pessoa, Paraiba, Brazil. Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. CNPq, Rio De Janeiro, Brazil. Yale Univ, JW Gibbs Lab, New Haven, CT 06511 USA. RP Barbosa, RF (reprint author), Univ Sao Paulo, Inst Fis, BR-05508 Sao Paulo, Brazil. RI Albuquerque, Ivone/H-4645-2012; Gouffon, Philippe/I-4549-2012 OI Albuquerque, Ivone/0000-0001-7328-0136; Gouffon, Philippe/0000-0001-7511-4115 NR 7 TC 1 Z9 1 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 FEB 1 PY 2000 VL 61 IS 3 AR 031101 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600001 ER PT J AU Brooks, TC Convery, ME Davis, WL Del Signore, KW Jenkins, TL Kangas, E Knepley, MG Kowalski, KL Taylor, CC Oh, SH Walker, WD Colestock, PL Hanna, B Martens, M Streets, J Ball, RC Gustafson, HR Jones, LW Longo, MJ Bjorken, JD Abashian, A Morgan, N Pruneau, CA AF Brooks, TC Convery, ME Davis, WL Del Signore, KW Jenkins, TL Kangas, E Knepley, MG Kowalski, KL Taylor, CC Oh, SH Walker, WD Colestock, PL Hanna, B Martens, M Streets, J Ball, RC Gustafson, HR Jones, LW Longo, MJ Bjorken, JD Abashian, A Morgan, N Pruneau, CA TI Search for disoriented chiral condensate at the Fermilab Tevatron SO PHYSICAL REVIEW D LA English DT Article ID HIGH-ENERGY COLLISIONS; HEAVY-ION COLLISIONS; CENTAURO-TYPE; EVENTS; FIELD AB We present results from MiniMax (Fermlab T-864), a small test/experiment at the Fermilab Tevatron designed to search for the production of a disoriented chiral condensate (DCC) in p-(p) over bar collisions at root s=1.8 TeV in the forward direction, similar to 3;4 < eta < similar to 4.2. Data, consisting of 1.3 x 10(6) events, are analyzed using the robust observables developed in an earlier paper. The results are consistent with generic, binomid-distribution partition of pions into charged and neutral species. Limits on DCC production in various models are presented. C1 Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Duke Univ, Dept Phys, Durham, NC 27708 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. Wayne State Univ, Dept Phys & Astron, Detroit, MI 48202 USA. RP Stanford Univ, Dept Phys, Stanford, CA 94305 USA. NR 44 TC 34 Z9 34 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 FEB 1 PY 2000 VL 61 IS 3 AR 032003 DI 10.1103/PhysRevD.61.032003 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600006 ER PT J AU Case, T Crowe, KM Heinsius, FH Kammel, P Lakata, M Degener, T Koch, H Kunze, M Kurilla, U Matthay, H Peters, K Ratajczak, M Stock, H Barnett, BM Herz, M Kalinowsky, H Klempt, E Pick, B Strassburger, C Suh, JS Thoma, U Wittmack, K Hidas, P Baker, CA Batty, CJ Doser, M Kisiel, J Landua, R Adomeit, J Meier, J Ouared, R Seibert, R Strohbusch, U Abele, A Bischoff, S Blum, P Engelhardt, D Herbstrith, A Holtzhaussen, C Tischhauser, M Bugg, DV Hodd, C Zou, BS Haddock, RP Braune, K Dunnweber, W Faessler, MA Hessey, NP Jamnik, D Kolo, C Roethel, W Volcker, C Uman, I Wallis-Plachner, S Walther, D Wiedner, U Berdoz, A McCrady, R Meyer, CA Suffert, M AF Case, T Crowe, KM Heinsius, FH Kammel, P Lakata, M Degener, T Koch, H Kunze, M Kurilla, U Matthay, H Peters, K Ratajczak, M Stock, H Barnett, BM Herz, M Kalinowsky, H Klempt, E Pick, B Strassburger, C Suh, JS Thoma, U Wittmack, K Hidas, P Baker, CA Batty, CJ Doser, M Kisiel, J Landua, R Adomeit, J Meier, J Ouared, R Seibert, R Strohbusch, U Abele, A Bischoff, S Blum, P Engelhardt, D Herbstrith, A Holtzhaussen, C Tischhauser, M Bugg, DV Hodd, C Zou, BS Haddock, RP Braune, K Dunnweber, W Faessler, MA Hessey, NP Jamnik, D Kolo, C Roethel, W Volcker, C Uman, I Wallis-Plachner, S Walther, D Wiedner, U Berdoz, A McCrady, R Meyer, CA Suffert, M CA Crystal Barrel Collaboration TI New analysis of the radiative decay omega ->eta gamma in proton-antiproton annihilation at rest SO PHYSICAL REVIEW D LA English DT Article ID PARTICLE PHYSICS; BRANCHING RATIO; OMEGA AB We report on a measurement of the branching ratio of the rare decay omega --> eta gamma relative to the well known decay omega --> pi(0)gamma. The omega's are produced in --> eta omega and --> pi(0)omega. Eigenstate mixing and interference effects. of the wand rho(0) are taken into account, as well as coherent interference with the background. We find evidence for the non-resonant annihilation channel B( --> eta eta gamma) = (3.5 +/- 1.3) x 10(-5) and limit the value of B(omega --> eta gamma) to the range of (0.7 to 5.5) x 10(-4) depending on the degree of coherence with the background. C1 Univ Calif Berkeley, LBNL, Berkeley, CA 94720 USA. Ruhr Univ Bochum, D-44780 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 4, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Univ Karlsruhe, D-76021 Karlsruhe, Germany. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Munich, D-80333 Munich, Germany. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Ctr Rech Nucl, F-67037 Strasbourg, France. RP Case, T (reprint author), Univ Calif Berkeley, LBNL, Berkeley, CA 94720 USA. RI Meyer, Curtis/L-3488-2014 OI Meyer, Curtis/0000-0001-7599-3973 NR 19 TC 2 Z9 2 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 FEB 1 PY 2000 VL 61 IS 3 AR 032002 DI 10.1103/PhysRevD.61.032002 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600005 ER PT J AU Lebed, RF AF Lebed, RF TI Radiative weak annihilation decays SO PHYSICAL REVIEW D LA English DT Article ID B-C MESON; SEARCH AB A class of meson decay modes sensitive to only one quark topology at leading C-F Order (annihilation of valence quarks through a W) is described. No experimental observations, or even upper limits, have been reported for these decays. This work presents a simpleminded (order-of-magnitude) calculation of their branching fractions, and compares to results of previous calculations where available. Although rare, one of these modes (D-s(+) --> rho(+) gamma) might already be observable at charm experiments; two others (D+ --> K*(+) gamma, B+ --> D-s*(+) gamma) should appear at the B factories, and the rest at hadron colliders. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Lebed, RF (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 18 TC 7 Z9 8 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 FEB 1 PY 2000 VL 61 IS 3 AR 033004 DI 10.1103/PhysRevD.61.033004 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600012 ER PT J AU Martin, SP AF Martin, SP TI Dimensionless supersymmetry breaking couplings, flat directions, and the origin of intermediate mass scales SO PHYSICAL REVIEW D LA English DT Article ID SYMMETRY-BREAKING; STANDARD MODEL; UNIFIED THEORIES; INVISIBLE AXION; GAUGE-THEORIES; DARK-MATTER; MU-PROBLEM; PHYSICS; BARYOGENESIS; SUPERGRAVITY AB The effects of supersymmetry breaking are usually parametrized by soft couplings of positive mass dimensions. However, realistic models also predict the existence of suppressed, but nonvanishing, dimensionless supersymmetry-breaking couplings. These couplings are technically hard, but do not lead to disastrous quadratic divergences in scalar masses, and may be crucial for understanding low-energy physics. In particular, analytic scalar quartic couplings that break supersymmetry can lead to intermediate scale vacuum expectation values along nearly flat directions. I study the one-loop effective potential for flat directions in the presence of dimensionless supersymmetry-breaking terms, and discuss the corresponding renormalization group equations. I discuss two applications: a minimal model of automatic R-parity conservation, and an extension of this minimal model which provides a solution to the mu problem and an invisible axion. C1 No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Martin, SP (reprint author), No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. NR 49 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 1 PY 2000 VL 61 IS 3 AR 035004 DI 10.1103/PhysRevD.61.035004 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600049 ER PT J AU Pripstein, D Gidal, G Ho, PM Kowitt, MS Luk, KB Isenhower, LD Sadler, ME Schnathorst, R Lederman, LM Schub, MH Brown, CN Cooper, WE Gounder, KN Mishra, CS Carey, TA Jansen, DM Jeppesen, RG Kapustinsky, JS Lane, DW Leitch, MJ Lillberg, JW McGaughey, PL Moss, JM Peng, JC Kaplan, DM Luebke, WR Preston, RS Sa, J Tanikella, V Childers, RL Darden, CW Wilson, JR Kiang, GC Teng, PK Chen, YC AF Pripstein, D Gidal, G Ho, PM Kowitt, MS Luk, KB Isenhower, LD Sadler, ME Schnathorst, R Lederman, LM Schub, MH Brown, CN Cooper, WE Gounder, KN Mishra, CS Carey, TA Jansen, DM Jeppesen, RG Kapustinsky, JS Lane, DW Leitch, MJ Lillberg, JW McGaughey, PL Moss, JM Peng, JC Kaplan, DM Luebke, WR Preston, RS Sa, J Tanikella, V Childers, RL Darden, CW Wilson, JR Kiang, GC Teng, PK Chen, YC TI Search for flavor-changing neutral currents and lepton-family-number violation in two-body D-0 decays SO PHYSICAL REVIEW D LA English DT Article ID SILICON STRIP DETECTORS; PARTICLE PHYSICS; MESON PRODUCTION; HIGH-SPEED; SYSTEM; CHARM; D-0->MU(+)MU(-); PREAMPLIFIER AB We present the results of a search for the three neutral charm decays D-0-->mu(+/-)e(-/+), D-0 --> mu(+)mu(-), and D-0 --> e(+)e(-). This study was based on data collected in Experiment 789 at the Fermi National Accelerator Laboratory using 800 GeV/c proton-Au and proton-Be interactions. No evidence is found for any of the decays. Upper limits on the branching ratios, at the 90% confidence level, of 1.56 x 10(-5) for D-0-->mu(+)mu(-), 8.19 x 10(-6) for D-0-->e(+)e(-) and 1.72 x 10(-5) for D-0-->mu(+/-)e(-/+) are obtained. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Abilene Christian Univ, Abilene, TX 79699 USA. Univ Chicago, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. No Illinois Univ, De Kalb, IL 60115 USA. Univ S Carolina, Columbia, SC 29208 USA. Acad Sinica, Inst Phys, Taipei, Taiwan. Natl Cheng Kung Univ, Tainan 70101, Taiwan. RP Pripstein, D (reprint author), CALTECH, Kellogg Lab, Pasadena, CA 91125 USA. NR 23 TC 5 Z9 6 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 FEB 1 PY 2000 VL 61 IS 3 AR 032005 DI 10.1103/PhysRevD.61.032005 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600008 ER PT J AU Tait, TMP AF Tait, TMP TI tW(-) mode of single top quark production SO PHYSICAL REVIEW D LA English DT Article ID W-GLUON FUSION; DEEP-INELASTIC SCATTERING; HEAVY-QUARK; QCD CORRECTIONS; HADRONIC COLLISIONS; FERMILAB-TEVATRON; CROSS-SECTION; COLLIDER; Q(Q)OVER-BAR->T(B)OVER-BAR; LEPTOPRODUCTION AB The t W- mode of single top quark production is proposed as an important means to study the weak interactions of the top quark. While the rate of this mode is most likely too small to be observed at ran II of the Fermilab Tevatron, it is expected to be considerably larger at the CERN LHC. In this article the inclusive t W- rate is computed, including O(1/log m(t)(w)/m(b)(2)) corrections, and when combined with detailed Monte Carlo simulations, including the top quark and W decay products, indicates that the t W- single top quark process may be extracted from the considerable t (t) over bar and W+ W- j backgrounds at low luminosity runs of the LHC. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Tait, TMP (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM tait@anl.gov NR 45 TC 80 Z9 80 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 FEB 1 PY 2000 VL 61 IS 3 AR 034001 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600021 ER PT J AU Weinstein, M AF Weinstein, M TI Quarks, gluons, and frustrated antiferromagnets SO PHYSICAL REVIEW D LA English DT Article ID SPIN; SEPARATION; CHAIN AB The contractor renormalization group method is used to establish the equivalence of various Hamiltonian free fermion theories and a class of generalized frustrated antiferromagnets. In particular, after a derailed discussion of a simple example, it is argued that a generalized frustrated SU(3) antiferromagnet whose single-site states have the quantum numbers of mesons and baryons is equivalent to a theory of free massless quarks. Furthermore, it is argued that for slight modification of the couplings which define the frustrated antiferromagnet Hamiltonian, the theory becomes a theory of quarks interacting with color gauge fields. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Weinstein, M (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 1 PY 2000 VL 61 IS 3 AR 034505 DI 10.1103/PhysRevD.61.034505 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 280AM UT WOS:000085079600045 ER PT J AU Schmidt, DM AF Schmidt, DM TI Continuous probability distributions from finite data SO PHYSICAL REVIEW E LA English DT Article ID INFERENCE AB Recent approaches to the problem of inferring a continuous probability distribution from a finite set of data have used a scalar held theory for the form of the prior probability distribution. This paper presents a more general form for the prior distribution that has a geometrical interpretation and can improve the specificity of likely solutions. It is also demonstrated that a numerical sampling of the posterior probability distribution can be used as an alternative to a histogram for visualization and to make probabilistic inferences from the data. C1 Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Schmidt, DM (reprint author), Univ Calif Los Alamos Natl Lab, Biophys Grp, POB 1663, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RR13630]; NIDA NIH HHS [DA/MH09972] NR 12 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1052 EP 1055 DI 10.1103/PhysRevE.61.1052 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600017 PM 11046373 ER PT J AU Mitkov, I Kladko, K Bishop, AR AF Mitkov, I Kladko, K Bishop, AR TI Localized structures in nonlinear lattices with diffusive coupling and external driving SO PHYSICAL REVIEW E LA English DT Article ID CHARGE-DENSITY WAVES; DYNAMICS; MODEL; PROPAGATION; NUCLEATION AB We study the stabilization of localized structures by discreteness in one-dimensional lattices of diffusively coupled nonlinear sites. We find that in an external driving field these structures may lose their stability by either relaxing to a homogeneous state or nucleating a pair of oppositely moving fronts. The corresponding bifurcation diagram demonstrates a cusp singularity. The obtained analytic results are in good quantitative agreement with numerical simulations. 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. RP Mitkov, I (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1106 EP 1109 DI 10.1103/PhysRevE.61.1106 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600024 ER PT J AU Fischer, R Hanson, KM Dose, V von der Linden, W AF Fischer, R Hanson, KM Dose, V von der Linden, W TI Background estimation in experimental spectra SO PHYSICAL REVIEW E LA English DT Article AB A general probabilistic technique for estimating background contributions to measured spectra is presented. A Bayesian model is used to capture the defining characteristics of the problem, namely, that the background is smoother than the signal. The signal is allowed to have positive and/or negative components. The background is represented in terms of a cubic spline basis. A variable degree of smoothness of the background is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity and allows uncertainties in the background to be estimated. Our technique is demonstrated on a particle induced x-ray emission spectrum from a geological sample and an Auger spectrum from iron, which contains signals with both positive and negative components. C1 EURATOM, Max Planck Inst Plasma Phys, D-85740 Garching, Germany. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Graz Univ Technol, Inst Theoret Phys, A-8010 Graz, Austria. RP EURATOM, Max Planck Inst Plasma Phys, D-85740 Garching, Germany. EM Rainer.Fischer@ipp.mpg.de; kmh@lanl.gov; von_der_Linden@itp.tu-graz.ac.at OI von der Linden, Wolfgang/0000-0001-7436-5078 NR 21 TC 41 Z9 41 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1152 EP 1160 DI 10.1103/PhysRevE.61.1152 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600031 ER PT J AU Meixner, M Zoldi, SM Bose, S Scholl, E AF Meixner, M Zoldi, SM Bose, S Scholl, E TI Karhunen-Loeve local characterization of spatiotemporal chaos in a reaction-diffusion system SO PHYSICAL REVIEW E LA English DT Article ID RAYLEIGH-BENARD CONVECTION; SPIRAL-DEFECT CHAOS; PATTERN-FORMATION; EXTENSIVE CHAOS; MODEL; DECOMPOSITION; TRANSITION; DIMENSION; DYNAMICS; SPIKING AB By computing the Karhunen-Loeve decomposition (KLD) correlation length xi(KLD) of a reaction-diffusion system in the extensive chaos regime, we show that it is a sensitive measure of spatial dynamical inhomogeneities. It reveals substantial spatial nonuniformity of the dynamics at the boundaries and can also detect slow spatial variations in system parameters. The intensive length xi(KLD) can be easily computed from small local subsystems and is found to have a similar parametric dependence as the two-point correlation length computed over the full system size. C1 Tech Univ Berlin, Inst Theoret Phys, D-10623 Berlin, Germany. 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. RP Meixner, M (reprint author), Tech Univ Berlin, Inst Theoret Phys, Hardenbergstr 36, D-10623 Berlin, Germany. NR 26 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1382 EP 1385 DI 10.1103/PhysRevE.61.1382 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600060 ER PT J AU Ramshaw, JD AF Ramshaw, JD TI Effect of slow compression on the linear stability of an accelerated shear layer SO PHYSICAL REVIEW E LA English DT Article AB An analysis is given of the effect of a slow uniform anisotropic compression or expansion an the linear stability of a normally accelerated planar interface between two fluids with different densities and tangential velocities, i.e., a combined Kelvin-Helmholtz and Rayleigh-Taylor instability, but generalized to an arbitrary time-dependent acceleration history. The compression is presumed to be sufficiently slow that the density remains uniform within each fluid and hence depends only on time. The perturbation is taken to be sinusoidal with amplitude h(t). The time evolution of It is determined by requiring pressure continuity across the interface in the usual way. The resulting Linearized stability equation is a second-order linear ordinary differential equation for h(t). Compared to the corresponding well-known result for incompressible fluids, it is found that normal compression has the effect of reducing the perturbation growth rate h by an obvious geometrical correction, while transverse compression does not directly affect the net growth rate but rather has the dynamical effect of increasing its time derivative. When attention is focused on the masses transported across the initial interface rather than h, the purely geometrical effects of compression no longer appear explicitly, while the dynamical effects remain. It is thereby shown that both normal and transverse compression dynamically enhance the mixing of material masses, in spite of the corresponding purely geometrical reduction in h. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Ramshaw, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-097, Livermore, CA 94551 USA. NR 9 TC 5 Z9 5 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1486 EP 1490 DI 10.1103/PhysRevE.61.1486 PG 5 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600072 ER PT J AU Wang, ZH Cohen, SA Ruzic, DN Goeckner, MJ AF Wang, ZH Cohen, SA Ruzic, DN Goeckner, MJ TI Nitrogen atom energy distributions in a hollow-cathode planar sputtering magnetron SO PHYSICAL REVIEW E LA English DT Article ID SURFACE; PLASMA; IONS AB Energy distributions of nitrogen atoms (N) in a hollow-cathode planar sputtering magnetron were obtained by use of optical emission spectroscopy. A characteristic line, N I 8216.3 Angstrom, well separated from molecular nitrogen emission bands, was identified. Jansson's nonlinear spectral deconvolution method, refined by minimization of chi(w)(2), was used to obtain the optimal deconvolved spectra. These showed nitrogen atom energies from 1 eV to beyond 500 eV. Based on comparisons with VFTRIM computer code results, it is proposed that the energetic N's are generated from N-2(+) ions after these ions are accelerated through the sheath and dissociatively reflect from the cathode. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Illinois, Dept Nucl Plasma & Radiol Engn, Urbana, IL 61801 USA. Univ Texas, Elect Engn Program, Plasma Sci Lab, Dallas, TX 75083 USA. RP Wang, ZH (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Goeckner, Matthew/A-8217-2009 NR 18 TC 18 Z9 18 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1904 EP 1911 DI 10.1103/PhysRevE.61.1904 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600120 ER PT J AU Baiko, DA Yakovlev, DG De Witt, HE Slattery, WL AF Baiko, DA Yakovlev, DG De Witt, HE Slattery, WL TI Coulomb crystals in the harmonic lattice approximation SO PHYSICAL REVIEW E LA English DT Article ID ONE-COMPONENT-PLASMA; WHITE-DWARFS; ION PLASMAS; EQUATION; MATTER; STATE; ENERGY AB The dynamic structure factor (S) over tilde(k,omega) and the two-particle distribution function g(r,t) of ions in a Coulomb crystal are obtained in a closed analytic form using the harmonic lattice (HL) approximation which takes into account all processes of multiphonon excitation and absorption. The static radial two-particle distribution function g(r) is calculated for classical (T greater than or similar to (h) over bar omega(p), where omega(p) is the ion plasma frequency) and quantum (T much less than (h) over bar omega(p)) body-centered-cubic (bcc) crystals. The results for the classical crystal are in a very good agreement with extensive Monte Carlo (MC) calculations at 1.5 less than or similar to r/a less than or similar to 7, where a is the ion-sphere radius. The HL Coulomb energy is calculated for classical and quantum bce and face-centered-cubic crystals, and anharmonic corrections are discussed. The inelastic part of the HL static structure factor S "(k), averaged over orientations of wave vector k, is shown to contain pronounced singularities at Bragg diffraction positions. The HL method can serve as a useful tool complementary to MC and other numerical methods. C1 AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Baiko, DA (reprint author), AF Ioffe Phys Tech Inst, Politekhnicheskaya 26, St Petersburg 194021, Russia. NR 16 TC 13 Z9 13 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1912 EP 1919 DI 10.1103/PhysRevE.61.1912 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600121 ER PT J AU Snyder, SC Crawford, DM Fincke, JR AF Snyder, SC Crawford, DM Fincke, JR TI Dependence on the scattering angle of the electron temperature and electron density in Thomson-scattering measurements on an atmospheric-pressure plasma jet SO PHYSICAL REVIEW E LA English DT Article ID LOCAL THERMODYNAMIC-EQUILIBRIUM; BURNING ARC; DEPARTURE AB Electron temperature and electron density measurements were made in an atmospheric-pressure argon plasma jet by line-shape analysis of Thomson-scattered laser light. The dependence of electron temperature and electron density on the scattering angle was investigated. Measurements were made using incident laser wavelengths of 532 and 355 nm. At 532 nm, the electron-ion collision frequency exceeds the Landau damping rate for shallow scattering angles, and the electron plasma wave resonance structure in thr Thomson line shape is broadened. This resulted in dramatic increase in the apparent electron temperature as a function of decreasing scattering angle. At 355 nm, collisions do not affect the Thomson line shape. In this case, an angular dependence of the measured electron temperature is not expected and was not observed. Data taken at 532 nm at larger scattering angles are consistent with the 355-nm results, and show that the electrons are not in thermodynamic equilibrium with the heavy particles. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Snyder, SC (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 10 TC 18 Z9 19 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1920 EP 1924 DI 10.1103/PhysRevE.61.1920 PG 5 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600122 ER PT J AU Radtke, R Biedermann, C Fuchs, T Fussmann, G Beiersdorfer, P AF Radtke, R Biedermann, C Fuchs, T Fussmann, G Beiersdorfer, P TI Measurement of the radiative cooling rates for high-ionization species of krypton using an electron beam ion trap SO PHYSICAL REVIEW E LA English DT Article ID DIELECTRONIC RECOMBINATION; SATELLITE LINES; CROSS-SECTIONS; HE-LIKE; POLARIZATION; PLASMAS; IMPURITIES; EXCITATION; SUBLEVELS; SPECTRA AB We describe a measurement of the radiative cooling rate for krypton made at the Berlin electron be;un ion trap (EBIT). The EBIT was tuned to a charge-state distribution approaching the ionization balance of a plasma at a temperature of about 5 keV. To determine the cooling rate, we made use of EBIT's capabilities to sample a wide range of electron-beam energies and distinguish between different radiation channels. We have measured the x-ray emission from bremsstrahlung, radiative recombination, dielectronic recombination, and line radiation following electron-impact excitation. The dominant contribution to the cooling rate is made by the n=3-2, n=4-2,... x rays of the L-shell spectra of krypton, which produce more than 75% of the total radiation loss. A difference with theoretical calculations is noted for the measured total cooling rate. The predicted Values are lower by a factor of 1.5-2, depending on the theoretical model. For our measurement of the cooling rate, we estimate an uncertainty interval of 22-30%. C1 EURATOM Assoc, Bereich Plasmadiagnost, Max Planck Inst Plasmaphys, D-10117 Berlin, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Radtke, R (reprint author), EURATOM Assoc, Bereich Plasmadiagnost, Max Planck Inst Plasmaphys, D-10117 Berlin, Germany. NR 23 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 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 1966 EP 1974 DI 10.1103/PhysRevE.61.1966 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600127 ER PT J AU Kevrekidis, PG Rasmussen, KO Bishop, AR AF Kevrekidis, PG Rasmussen, KO Bishop, AR TI Two-dimensional discrete breathers: Construction, stability, and bifurcations SO PHYSICAL REVIEW E LA English DT Article ID INTRINSIC LOCALIZED MODES; LATTICES; EXISTENCE AB We develop a methodology for the construction of two-dimensional discrete breather excitations. Application to the discrete nonlinear Schrodinger equation on a square lattice reveals three different types of breathers. Considering an elementary plaquette, the most unstable mode is centered on the plaquette, the most stable mode is centered on its vertices, while the intermediate (but also unstable) mode is centered at the middle of one of the edges. Below the turning points of each branch in a frequency-power phase diagram, the construction methodology fails and a continuation method is used to obtain the unstable branches of the solutions until a triple point is reached. At this triple point, the branches meet and subsequently bifurcate into the final, state of an extended phonon mode. 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. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Kevrekidis, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Rasmussen, Kim/B-5464-2009 OI Rasmussen, Kim/0000-0002-4029-4723 NR 26 TC 43 Z9 43 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 2006 EP 2009 DI 10.1103/PhysRevE.61.2006 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600133 ER PT J AU Daughton, W Murillo, MS Thode, L AF Daughton, W Murillo, MS Thode, L TI Empirical bridge function for strongly coupled Yukawa systems SO PHYSICAL REVIEW E LA English DT Article ID ONE-COMPONENT-PLASMA; HYPERNETTED-CHAIN EQUATION; INTEGRAL-EQUATIONS; IMPROVEMENT; LIMIT AB A simple bridge function for strongly coupled Yukawa systems is developed based upon a form previously extracted for a one-component plasma [H. Iyetomi, S. Ogata, and S. Ichimaru. Phys. Rev. A 46, 1051 (1992)]. Using the proposed bridge function in the modified hypernetted chain theory, excellent agreement is obtained with molecular dynamics simulations and the compressibility sum rule is satisfied to within a few percent. This result offers a simple and very accurate method to quickly compute correlation functions for Yukawa systems. C1 Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. RI Daughton, William/L-9661-2013 NR 26 TC 15 Z9 15 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 2129 EP 2132 DI 10.1103/PhysRevE.61.2129 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600156 ER PT J AU Mitkov, I Tartakovsky, DM Winter, CL AF Mitkov, I Tartakovsky, DM Winter, CL TI Reply to "Comment on 'Dynamics of wetting fronts in porous media'" SO PHYSICAL REVIEW E LA English DT Letter AB In our work [Phys. Rev. E 58, R5245 (1998)] we introduced a dynamic phenomenological approach to model propagation of localized wetting fronts in porous media. Gray and Miller in their Comment [Phys. Rev. E 61, 2150 (2000)] criticize our approach on several issues. The main criticism addresses the problem of mass conservation in our model. In this Reply we argue that their criticism is incorrect. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Sci Comp Grp, Los Alamos, NM 87545 USA. RP Mitkov, I (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RI Tartakovsky, Daniel/E-7694-2013; Winter, C. Larrabee/D-3918-2013 NR 3 TC 4 Z9 4 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2000 VL 61 IS 2 BP 2152 EP 2153 DI 10.1103/PhysRevE.61.2152 PG 2 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 285WD UT WOS:000085410600163 ER PT J AU Krapivsky, PL Grosse, I Ben-Naim, E AF Krapivsky, PL Grosse, I Ben-Naim, E TI Scale invariance and lack of self-averaging in fragmentation SO PHYSICAL REVIEW E LA English DT Article ID DISORDERED-SYSTEMS; DNA-SEQUENCES; FRACTALS; OBJECTS; MODEL AB We derive exact statistical properties of a recursive fragmentation process. We show that introducing a fragmentation probability 0 0, this can be generalized to h(i)=2 alpha(i)AS using S=[integral root gdt](2)/2 rather than the displacement Z=integral integral gdt(') dt. For impulsive accelerations, S remains constant during the coast phase and the amplitudes obey a power law h(i)similar to t(theta i) with theta(2)similar to 0.25 +/- 0.05 and theta(1)similar to theta(2)R(D theta) with D(theta)similar to 0.21 +/- 0.05. These values of D-alpha and D-theta compare favorably with numerical simulations and mix models. The average diameter at the mixing front for bubbles is found to increase as d(2)similar to h(2)(1+A)/4 in qualitative agreement with "merger" models, but the associated dh(i)/dt is two times larger than the terminal velocity of an isolated bubble. The spikes become relatively narrow at large R, yet they still grow as gt(2). (C) 2000 American Institute of Physics. [S1070-6631(00)00102-1]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dimonte, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 75 TC 180 Z9 182 U1 4 U2 33 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 FEB PY 2000 VL 12 IS 2 BP 304 EP 321 DI 10.1063/1.870309 PG 18 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 271MV UT WOS:000084598800010 ER PT J AU Kerstein, AR Dreeben, TD AF Kerstein, AR Dreeben, TD TI Prediction of turbulent free shear flow statistics using a simple stochastic model SO PHYSICS OF FLUIDS LA English DT Article ID SIMULATION; TRANSPORT AB One-dimensional turbulence, a stochastic simulation of turbulent flow evolution based on application of a mixing-length-type hypothesis to individual turbulent eddies, is used to predict transverse profiles of single-point statistics up to third order for two time-developing planar free shear flows, a mixing layer and a wake. Comparison of computed results to statistics obtained from direct numerical simulations of these flows indicates that the model, despite its simplicity, captures important features of turbulent free shear flow structure. Implications concerning the possible universality of some aspects of turbulent shear flow are discussed. (C) 2000 American Institute of Physics. [S1070-6631(00)01002-3]. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Kerstein, AR (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 11 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 2000 VL 12 IS 2 BP 418 EP 424 DI 10.1063/1.870319 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 271MV UT WOS:000084598800020 ER PT J AU Gary, SP Kazimura, Y Li, H Sakai, JI AF Gary, SP Kazimura, Y Li, H Sakai, JI TI Simulations of electron/electron instabilities: Electromagnetic fluctuations SO PHYSICS OF PLASMAS LA English DT Article ID NIGHTSIDE AURORAL REGION; PLASMA-WAVES; ELECTRON FORESHOCK; BEAM-PLASMA; POLAR-CAP; GENERATION; EMISSIONS; TRANSITION; DAYSIDE; 2F(P) AB Electron/electron instabilities arise in collisionless plasmas when the electron velocity distribution consists of two distinct components with a sufficiently large relative drift speed between them. If the less dense beam component is not too tenuous and sufficiently fast, the electron/electron beam instability is excited over a relatively broad range of frequencies. This instability is often studied in the electrostatic limit, which is appropriate at omega(e)/\Omega(e)\ much greater than 1, where omega(e) is the electron plasma frequency and Omega(e) is the electron cyclotron frequency, but is not necessarily valid at omega(e)/\Omega(e)\ similar to 1. Here linear Vlasov dispersion theory has been used and fully electromagnetic particle-in-cell simulations have been run in a spatially homogeneous, magnetized plasma model at beta(e) much less than 1 and 0.5 less than or equal to omega(e)/\Omega(e)\ less than or equal to 4.0. Theory and simulations (run to times of order 100 omega(e)(-1)) of the electron/electron beam instability show the growth of appreciable magnetic fluctuations at omega(e)/\Omega(e)\ < 2; these waves bear right-hand elliptical magnetic polarization. The simulations reproduce the well-known slowing and heating of the beam; at omega(e)/\Omega(e)\ < 1 this heating is predominantly parallel to the background magnetic field, but as omega(e)/\Omega(e)\ becomes greater than unity the perpendicular heating of the beam increases. The simulations also demonstrate that, for omega(e)/\Omega(e)\ similar to 1, electromagnetic fluctuations impart to the more dense electron core component significant heating perpendicular to the background magnetic field. (C) 2000 American Institute of Physics. [S1070-664X(00)00202-0]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Toyama Univ, Lab Plasma Astrophys, Toyama 930, Japan. RP Gary, SP (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 25 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2000 VL 7 IS 2 BP 448 EP 456 DI 10.1063/1.873829 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700006 ER PT J AU Sugama, H AF Sugama, H TI Gyrokinetic field theory SO PHYSICS OF PLASMAS LA English DT Article ID GUIDING CENTER MOTION; CONSERVATION-LAWS; VLASOV EQUATION; MAXWELL-VLASOV; PLASMAS; FORMULATION; PRINCIPLES; TOKAMAKS; MODES; FLOWS AB The Lagrangian formulation of the gyrokinetic theory is generalized in order to describe the particles' dynamics, as well as the self-consistent behavior of the electromagnetic fields. The gyrokinetic equation for the particle distribution function and the gyrokinetic Maxwell's equations, for the electromagnetic fields, are both derived from the variational principle for the Lagrangian consisting of the parts of particles, fields, and their interaction. In this generalized Lagrangian formulation, the energy conservation property for the total nonlinear gyrokinetic system of equations is directly shown from Noether's theorem. This formulation can be utilized in order to derive the nonlinear gyrokinetic system of equations and the rigorously conserved total energy for fluctuations with arbitrary frequencies. Simplified gyrokinetic systems of equations with the conserved energy are obtained from the Lagrangian with the small electron gyroradii, quasineutrality, and linear polarization-magnetization approximations. (C) 2000 American Institute of Physics. [S1070-664X(00)02502-7]. C1 Natl Inst Fus Sci, Toki 5095292, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Sugama, H (reprint author), Natl Inst Fus Sci, Toki 5095292, Japan. RI Sugama, Hideo/E-7541-2013 OI Sugama, Hideo/0000-0001-5444-1758 NR 37 TC 81 Z9 81 U1 0 U2 16 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 FEB PY 2000 VL 7 IS 2 BP 466 EP 480 DI 10.1063/1.873832 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700009 ER PT J AU Weitzner, H Berry, LA Jaeger, EF Batchelor, DB AF Weitzner, H Berry, LA Jaeger, EF Batchelor, DB TI Ion flow driven by waves in the ion cyclotron frequency range SO PHYSICS OF PLASMAS LA English DT Article AB An ion kinetic equation is solved by expansion in a parameter corresponding to the small parameter of neoclassical transport theory and the small parameter of geometrical optics. A slab model with perpendicular stratification of the magnetic field is assumed, and a given rf (radio frequency) field is present with a frequency corresponding to a modest multiple of the ion cyclotron frequency. The rf induced ion flow perpendicular to the magnetic field is calculated. The parallel flow may be large, but it cannot be calculated without an analysis of the electron transport. (C) 2000 American Institute of Physics. [S1070-664X(00)03602-8]. C1 NYU, Courant Inst Math Sci, New York, NY 10012 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Weitzner, H (reprint author), NYU, Courant Inst Math Sci, 251 Mercer St, New York, NY 10012 USA. NR 6 TC 6 Z9 6 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 FEB PY 2000 VL 7 IS 2 BP 564 EP 570 DI 10.1063/1.873842 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700019 ER PT J AU Lewandowski, JLV Lin, Z Lee, WW Hahm, TS AF Lewandowski, JLV Lin, Z Lee, WW Hahm, TS TI Sheared-flow modes in toroidal geometry SO PHYSICS OF PLASMAS LA English DT Article ID PARTICLE SIMULATION; TURBULENCE; TRANSPORT; MICROTURBULENCE; TOKAMAKS; DEVICES AB Using a Fourier-Bessel representation for the fluctuating (turbulent) electrostatic potential, an equation governing the sheared-flow modes in toroidal geometry is derived from the gyrokinetic Poisson equation, where both the adiabatic and nonadiabatic responses of the electrons are taken into account. It is shown that the principal geometrical effect on sheared-flow modes of the electrostatic potential is due to the flux-surface average of 1/B, where B is the magnetic field strength. (C) 2000 American Institute of Physics. [S1070-664X(00)00302-5]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Lewandowski, JLV (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 16 TC 3 Z9 3 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 FEB PY 2000 VL 7 IS 2 BP 588 EP 595 DI 10.1063/1.873845 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700022 ER PT J AU Ernst, DR Bell, RE Bell, MG Budny, RV Coppi, B Hammett, GW Hawryluk, RJ Hill, KW Mansfield, DK Mikkelsen, DR Park, HK Porkolab, M Scott, SD Schmidt, GL Synakowski, EJ Zarnstorff, MC AF Ernst, DR Bell, RE Bell, MG Budny, RV Coppi, B Hammett, GW Hawryluk, RJ Hill, KW Mansfield, DK Mikkelsen, DR Park, HK Porkolab, M Scott, SD Schmidt, GL Synakowski, EJ Zarnstorff, MC CA TFTR Grp TI Transitionless enhanced confinement and the role of radial electric field shear SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT Meeting of the American-Institute-of-Physics Division of Plasma Physics CY NOV, 1998 CL NEW ORLEANS, LOUISIANA SP Amer Inst Phys, Div Plasma Phys ID FUSION TEST REACTOR; TFTR SUPERSHOT PLASMAS; ION-TEMPERATURE; ASPECT RATIO; NEOCLASSICAL TRANSPORT; ENERGY CONFINEMENT; POLOIDAL ROTATION; VELOCITY PROFILES; TOKAMAK PLASMAS; TURBULENCE AB Evidence is presented for the role of radial electric field shear in enhanced confinement regimes attained without sharp bifurcations or transitions. Temperature scans at constant density, created in the reheat phase following deuterium pellet injection into supershot plasmas in the Tokamak Fusion Test Reactor [J. D. Strachan, , Phys. Rev. Lett. 58, 1004 (1987)] are simulated using a physics-based transport model. The slow reheat of the ion temperature profile, during which the temperature nearly doubles, is not explained by relatively comprehensive models of transport due to Ion Temperature Gradient Driven Turbulence (ITGDT), which depends primarily on the (unchanging) electron density gradient. An extended model, including the suppression of toroidal ITGDT by self-consistent radial electric field shear, does reproduce the reheat phase. The extended reheat at constant density is observed in supershot but not L-Mode plasmas. (C) 2000 American Institute of Physics. [S1070-664X(00)01102-2]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. MIT, Cambridge, MA 02139 USA. RP Ernst, DR (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Hammett, Gregory/D-1365-2011; Ernst, Darin/A-1487-2010 OI Hammett, Gregory/0000-0003-1495-6647; Ernst, Darin/0000-0002-9577-2809 NR 44 TC 11 Z9 11 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 FEB PY 2000 VL 7 IS 2 BP 615 EP 625 DI 10.1063/1.873867 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700025 ER PT J AU Jaeger, EF Berry, LA Batchelor, DB AF Jaeger, EF Berry, LA Batchelor, DB TI Second-order radio frequency kinetic theory with applications to flow drive and heating in tokamak plasmas SO PHYSICS OF PLASMAS LA English DT Article ID SHEAR SUPPRESSION; EDGE TURBULENCE; WAVES; POWER; TRANSPORT AB A comprehensive kinetic theory is developed to treat radio frequency (rf) driven plasma flow in one-dimensional geometry. The kinetic equation is expanded to second order in the perturbing rf electric field. No assumption is made regarding the smallness of the ion Larmor radius relative to wavelength. Moments of the second-order distribution function give time-averaged expressions for the rf-driven particle transport, forces, and heating, including the wave kinetic flux. On the transport time scale, the rf force in the poloidal direction is balanced by neoclassical viscosity, and the force in the radial direction is balanced by ambipolar electric fields. Comparison is made with previous theories which have relied on incompressible fluid approximations and a Reynolds stress model for the rf pressure. Substantial differences are seen in situations involving the ion Bernstein wave, which is compressional in nature. Linear electron Landau damping and magnetic pumping, by themselves, do not lead to significant poloidal flow. But ion cyclotron damping of either fast magnetosonic waves or ion Bernstein waves can drive significant flow at power levels typical of plasma heating experiments. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Jaeger, EF (reprint author), Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA. NR 30 TC 28 Z9 29 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2000 VL 7 IS 2 BP 641 EP 656 DI 10.1063/1.873868 PG 16 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700029 ER PT J AU Baker, KL Porter, JL Ruggles, LE Chandler, GA Deeney, C Vargas, M Moats, A Struve, K Torres, J McGurn, JS Simpson, WW Fehl, DL Jobe, DO Chrien, RE Matuska, W Idzorek, GC AF Baker, KL Porter, JL Ruggles, LE Chandler, GA Deeney, C Vargas, M Moats, A Struve, K Torres, J McGurn, JS Simpson, WW Fehl, DL Jobe, DO Chrien, RE Matuska, W Idzorek, GC TI Characterization of diagnostic hole-closure in Z-pinch driven hohlraums SO PHYSICS OF PLASMAS LA English DT Article ID INERTIAL CONFINEMENT FUSION; X-RAY POWER; HIGH-TEMPERATURES; RADIATION; INSTABILITY; SYMMETRY; OPACITY AB In this article we investigate the partial closure of diagnostic holes in Z-pinch driven hohlraums. These hohlraums differ from current laser-driven hohlraums in a number of ways such as their larger size, greater x-ray drive energy, and lower temperature. Although the diameter of the diagnostic holes on these Z-pinch driven hohlraums can be much greater than their laser-driven counterparts, 4 mm in diameter or larger, radiation impinges on the wall material surrounding the hole for the duration of the Z pinch, nearly 100 ns. This incident radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and partially obscure this diagnostic hole. This partial obscuration reduces the effective area over which diagnostics view the hohlraum's radiation. This reduction in area can lead 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. In this article we describe the techniques used to characterize the hole-closure in these hohlraums and present the experimental measurements of this process. (C) 2000 American Institute of Physics. [S1070-664X(00)02802-0]. C1 Sandia Natl Lab, 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 30 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2000 VL 7 IS 2 BP 681 EP 688 DI 10.1063/1.873852 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700032 ER PT J AU Lemke, RW Genoni, TC Spencer, TA AF Lemke, RW Genoni, TC Spencer, TA TI Investigation of rising-sun magnetrons operated at relativistic voltages using three-dimensional particle-in-cell simulation SO PHYSICS OF PLASMAS LA English DT Article ID EMISSION AB This work is an attempt to elucidate effects that may limit efficiency in magnetrons operated at relativistic voltages (V similar to 500 kV). Three-dimensional particle-in-cell simulation is used to investigate the behavior of 14 and 22 cavity, cylindrical, rising-sun magnetrons. Power is extracted radially through a single iris located at the end of every other cavity. Numerical results show that in general output power and efficiency increase approximately linearly with increasing iris width (decreasing vacuum Q) until the total Q becomes too low for stable oscillation in the pi-mode to be maintained. Beyond this point mode competition and/or switching occur and efficiency decreases. Results reveal that the minimum value of Q (maximum efficiency) that can be achieved prior to the onset of mode competition is significantly affected by the magnitude of the 0-space-harmonic of the pi-mode, a unique characteristic of rising suns, and by the magnitude of the electron current density (space-charge effects). By minimizing these effects, up to 3.7 GW output power has been produced at an efficiency of 40%. (C) 2000 American Institute of Physics. [S1070-664X(00)03502-3]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Mission Res Corp, Albuquerque, NM 87110 USA. USAF, Res Lab, Kirtland AFB, NM 87117 USA. RP Lemke, RW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 19 TC 11 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2000 VL 7 IS 2 BP 706 EP 714 DI 10.1063/1.873856 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 275LY UT WOS:000084822700036 ER PT J AU Xu, YS Shankland, TJ Duba, AG AF Xu, YS Shankland, TJ Duba, AG TI Pressure effect on electrical conductivity of mantle olivine SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article DE pressure; electrical conductivity; mantle olivine ID OXYGEN FUGACITY; POLYCRYSTALLINE OLIVINE; TEMPERATURE; TRANSITION; PROFILE; BENEATH; MODEL; MELT AB We report new measurements of electrical conductivity of olivine that were made in a multi-anvil press using solid buffers (Mo-MoO2) to stabilize oxygen partial pressure. The temperature range was 1000 degrees C-1400 degrees C and the pressure range was 4-10 GPa. When pressure effects are interpreted as activation volumes in the Arrhenius equation, they yield values of order 0.6 +/- 0.6 cm(3)/mole. Values of the pre-exponential factor sigma(0) are of the order of hundreds of S/m, and the zero-pressure activation energy is about 1.5 eV, in agreement with laboratory measurements at lower pressure conditions. In addition, we analyzed older literature data, which produced a similar result but with larger variation. The common practice of assuming that the pressure effect on electrical conductivity of olivine in the Earth's upper mantle depends weakly on pressure has rested on uncertain grounds. These new observations suggest that for upper mantle conditions (depths of 80-200 km) neglecting pressure effects on olivine conductivity is justified. A weak pressure effect also supports the small polaron (Fe3+) model as the dominant conduction mechanism, although the mainly positive activation volumes argue for a component of lattice deformation. When applied to the depth range 200-400 km in the Earth, the laboratory data yield conductivities of order 10(-2) S/m, slightly lower than the range of geophysical conductivity profiles but well within this range after allowing for probable effects of oxygen activity and temperature uncertainty. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Earth & Environm Sci Directorate, Livermore, CA 94551 USA. RP Shankland, TJ (reprint author), Univ Bayreuth, Bayer Geoinst, POB 101251, D-95440 Bayreuth, Germany. NR 50 TC 103 Z9 117 U1 8 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD FEB PY 2000 VL 118 IS 1-2 BP 149 EP 161 DI 10.1016/S0031-9201(99)00135-1 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 274KC UT WOS:000084764200012 ER PT J AU Rosenberg, LJ van Bibber, KA AF Rosenberg, LJ van Bibber, KA TI Searches for invisible axions SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID ELECTRIC-DIPOLE MOMENT; STRONG CP PROBLEM; COSMIC AXIONS; QUANTUM CHROMODYNAMICS; LIGHT PSEUDOSCALARS; MAGNETIC-FIELD; SOLAR AXIONS; UPPER LIMIT; BEAM-DUMP; PARTICLES AB The axion, a hypothetical elementary particle, emerged from a compelling solution to the Strong-CP problem in QCD, Subsequently, the axion was recognized to be a good Cold Dark Matter candidate. Although dark matter axions have only feeble couplings to matter and radiation, extremely sensitive searches are underway around the world. We review the state of experiments searching for the axion through its coupling to photons. Besides answering an outstanding question in particle physics, the discovery of dark matter axions may provide a detailed history of the formation of our Milky Way galaxy through the structure of the axion signal. (C) 2000 Elsevier Science B.V. All rights reserved. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94550 USA. RP Rosenberg, LJ (reprint author), MIT, Dept Phys, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM ljr@mitlns.mit.edu NR 79 TC 97 Z9 100 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD FEB PY 2000 VL 325 IS 1 BP 1 EP 39 DI 10.1016/S0370-1573(99)00045-9 PG 39 WC Physics, Multidisciplinary SC Physics GA 282ZV UT WOS:000085252400001 ER PT J AU Goodwin, I AF Goodwin, I TI Los Alamos director talks about security problems, morale, and recruiting young scientists at lab SO PHYSICS TODAY LA English DT Editorial Material C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 0 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 0031-9228 J9 PHYS TODAY JI Phys. Today PD FEB PY 2000 VL 53 IS 2 BP 46 EP 49 PG 4 WC Physics, Multidisciplinary SC Physics GA 281TY UT WOS:000085177900011 ER PT J AU Kharzeev, D Pisarski, R Tytgat, M AF Kharzeev, D Pisarski, R Tytgat, M TI More on history of P, CP, T violation in strong interactions - Reply SO PHYSICS TODAY LA English DT Letter C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Free Univ Brussels, Brussels, Belgium. RP Kharzeev, D (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 6 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 0031-9228 J9 PHYS TODAY JI Phys. Today PD FEB PY 2000 VL 53 IS 2 BP 76 EP 76 PG 1 WC Physics, Multidisciplinary SC Physics GA 281TY UT WOS:000085177900023 ER PT J AU Striolo, A Prausnitz, JM AF Striolo, A Prausnitz, JM TI Vapor-liquid equilibria for some concentrated aqueous polymer solutions SO POLYMER LA English DT Article DE vapor-liquid equilibrium; polymers; gravimetric-sorption method ID DYNAMIC LIGHT-SCATTERING; CRITICAL SOLUTION TEMPERATURE; POLY(VINYL ALCOHOL); MOLECULAR-WEIGHT; BORAX SOLUTIONS; WATER-VAPOR; PROTEIN INTERACTIONS; 2-PHASE SYSTEMS; SORPTION; VISCOELASTICITY AB Vapor-liquid-equilibrium data were obtained for binary aqueous solutions of six water-soluble linear polymers in the range 70-95 degrees C. A classical gravimetric sorption method was used to measure the amount of solvent absorbed as a function of vapor-phase water pressure. Polymers studied were polyvinylpyrrolidone, polyethyleneoxide, polyvinylalcohol, hydroxyethylcellulose, polyethylenimine, polymethylvinylether. The experimental data were reduced with Hino's lattice model that distinguished the interactions due to London dispersion forces and those due to hydrogen bonding. (C) 1999 Elsevier Science Ltd. AU rights reserved. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Striolo, Alberto/G-2926-2011 NR 66 TC 17 Z9 17 U1 2 U2 12 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD FEB PY 2000 VL 41 IS 3 BP 1109 EP 1117 DI 10.1016/S0032-3861(99)00256-6 PG 9 WC Polymer Science SC Polymer Science GA 256NV UT WOS:000083732400032 ER PT J AU Zhu, YW Jong, MC Frazer, KA Gong, E Krauss, RM Cheng, JF Boffelli, D Rubin, EM AF Zhu, YW Jong, MC Frazer, KA Gong, E Krauss, RM Cheng, JF Boffelli, D Rubin, EM TI Genomic interval engineering of mice identifies a novel modulator of triglyceride production SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID EMBRYONIC STEM-CELLS; SUPPRESSED EXPRESSION; CARNITINE; HYPERLIPOPROTEINEMIA; RECOMBINATION; HEMODIALYSIS; SEQUENCE; PLASMA; GENES; OCTN2 AB To accelerate the biological annotation of novel genes discovered in sequenced regions of mammalian genomes, we are creating large deletions in the mouse genome targeted to include clusters of such genes. Here we describe the targeted deletion of a 450-kb region on mouse chromosome 11, which, based on computational analysis of the deleted murine sequences and human 5q orthologous sequences, codes for nine putative genes. Mice homozygous for the deletion had a variety of abnormalities, including severe hypertriglyceridemia. hepatic and cardiac enlargement, growth retardation, and premature mortality. Analysis of triglyceride metabolism in these animals demonstrated a several-fold increase in hepatic very-low density lipoprotein triglyceride secretion, the most prevalent mechanism responsible for hypertriglyceridemia in humans. A series of mouse BAC and human YAC transgenes covering different intervals of the 450-kb deleted region were assessed for their ability to complement the deletion induced abnormalities. These studies revealed that OCTN2, a gene recently shown to play a role in carnitine transport, was able to correct the triglyceride abnormalities. The discovery of this previously unappreciated relationship between OCTN2, carnitine, and hepatic triglyceride production is of particular importance because of the clinical consequence of hypertriglyceridemia and the paucity of genes known to modulate triglyceride secretion. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, Berkeley, CA 94720 USA. TNO Prevent & Hlth, Gaubius Lab, NL-2333 CK Leiden, Netherlands. RP Rubin, EM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, 1 Cyclotron Rd,MS-84-171, Berkeley, CA 94720 USA. FU PHS HHS [NIH 50590, NIH 18574] NR 30 TC 30 Z9 32 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 1 PY 2000 VL 97 IS 3 BP 1137 EP 1142 DI 10.1073/pnas.97.3.1137 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 281BM UT WOS:000085138300035 PM 10655497 ER PT J AU Buchko, GW Hess, NJ Kennedy, MA AF Buchko, GW Hess, NJ Kennedy, MA TI Human nucleotide excision repair protein XPA: Summary of exafs studies on the Zn (II), Co (II) and Cd (II) associated minimal DNA-binding domain SO PROTEIN AND PEPTIDE LETTERS LA English DT Article ID XERODERMA-PIGMENTOSUM; DAMAGE-RECOGNITION; FACTOR TFIIH; ZINC; CELLS; RPA AB The zinc in the metal-binding core of the DNA-binding domain of the nucleotide excision repair protein XPA (M98-F219) can be replaced with cadmium (II) and cobalt(II). Here, we summarize extended X-ray fine structure spectra collected on each protein in the lyophilized state and in 15% frozen aqueous glycerol solution. Under both conditions the Zn2+, Cd2+, and Co2+ are tetrahedrally coordinated to the sulfur atom of four cysteine residues with the Zn-S and Co-S bond lengths nearly identical, at 2.34 Angstrom, and the Cd-S bond length at 2.54 Angstrom. C1 Pacific NW Lab, Environm Mol Sci Lab & Biogeochem Resources, Richland, WA 99352 USA. RI Buchko, Garry/G-6173-2015; OI Buchko, Garry/0000-0002-3639-1061; Hess, Nancy/0000-0002-8930-9500 NR 33 TC 9 Z9 10 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 FEB PY 2000 VL 7 IS 1 BP 49 EP 56 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 286VK UT WOS:000085469400008 ER PT J AU Wittig, A Sauerwein, WA Coderre, JA AF Wittig, A Sauerwein, WA Coderre, JA TI Mechanisms of transport of p-borono-phenylalanine through the cell membrane in vitro SO RADIATION RESEARCH LA English DT Article ID AMINO-ACID-TRANSPORT; NEUTRON-CAPTURE THERAPY; GLIOBLASTOMA-MULTIFORME; MELANOMA-CELLS; BRAIN-TUMORS; L-TYROSINE; IN-VITRO; BORONOPHENYLALANINE; RAT; ASTROCYTES AB The mechanisms of transport of p-(dihydroxyboryl)-phenylalanine (BPA) through the cell membrane were investigated in vitro, evaluating especially the systems responsible for the transport of neutral amino acids as potential carriers for BPA, Rat 9L, gliosarcoma cells and Chinese hamster V79 cells were exposed to BPA under controlled conditions and in a defined medium that was free of amino acids. The time course of B-10 (delivered by BPA) uptake and efflux was measured under different conditions. To analyze the intracellular boron content, direct-current plasma atomic emission spectroscopy (DCP-AES) was used after separating the cells from extracellular boron in the cell medium using an oil filtration technique. The dependence of factors such as cell type, temperature, composition and concentration of amino acids and specific substrates for amino acid transport systems in the culture medium or in intracellular compartments on BPA uptake and efflux were studied. The results of this study support the hypothesis that BPA is transported by the L system and that transport can be further stimulated by amino acids preaccumulated in the cell by either the L or A amino acid transport system. (C) 2000 by Radiation Research Society. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Univ Essen Gesamthsch, Dept Radiat Oncol, D-45122 Essen, Germany. RP Wittig, A (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. NR 40 TC 75 Z9 77 U1 2 U2 6 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 FEB PY 2000 VL 153 IS 2 BP 173 EP 180 DI 10.1667/0033-7587(2000)153[0173:MOTOPB]2.0.CO;2 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 280BK UT WOS:000085082000006 PM 10629616 ER PT J AU Metting, NF AF Metting, NF TI Responses of XRCC5 protein after heavy-ion traversal of cells SO RADIATION RESEARCH LA English DT Meeting Abstract C1 Pacific NW Lab, Mol Biosci Dept, Richland, WA 99352 USA. NR 0 TC 1 Z9 1 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 FEB PY 2000 VL 153 IS 2 BP 228 EP 228 PG 1 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 280BK UT WOS:000085082000023 ER PT J AU Lobrich, M Kuhne, M Rothkamm, K Rydberb, B Cooper, PK AF Lobrich, M Kuhne, M Rothkamm, K Rydberb, B Cooper, PK TI Comments on the paper "No detectable misrejoining in double-minute chromosomes" by Nevaldine et al. (Radiat. Res. 152, 154-159, 1999) SO RADIATION RESEARCH LA English DT Letter C1 Univ Saarlandes, Fachrichtung Biophys & Phys Grundiagen Med, D-66421 Homburg, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Lobrich, M (reprint author), Univ Saarlandes, Fachrichtung Biophys & Phys Grundiagen Med, D-66421 Homburg, Germany. RI Rothkamm, Kai/A-2164-2014 OI Rothkamm, Kai/0000-0001-7414-5729 NR 2 TC 0 Z9 0 U1 0 U2 0 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD FEB PY 2000 VL 153 IS 2 BP 239 EP 239 DI 10.1667/0033-7587(2000)153[0239:COTPND]2.0.CO;2 PG 1 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 280BK UT WOS:000085082000037 ER PT J AU Nevaldine, B Hahn, P AF Nevaldine, B Hahn, P TI Comments on the paper "No detectable misrejoining in double-minute chromosomes" by Nevaldine et al. (Radiat. Res. 152, 154-159, 1999) - Response SO RADIATION RESEARCH LA English DT Letter ID DOUBLE-STRAND BREAKS; HUMAN FIBROBLASTS; FRAGMENTS C1 Univ Saarlandes, Fachrichtung Biophys & Phys Grundiagen Med, D-66421 Homburg, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Nevaldine, B (reprint author), Univ Saarlandes, Fachrichtung Biophys & Phys Grundiagen Med, D-66421 Homburg, Germany. NR 3 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 FEB PY 2000 VL 153 IS 2 BP 239 EP 240 PG 2 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 280BK UT WOS:000085082000038 ER PT J AU Sullivan, GP Hyner, R Masella, P AF Sullivan, GP Hyner, R Masella, P TI The NICE3-Whyco technologies partnership: saving energy, dollars, and the environment in the metal plating industry SO RESOURCES CONSERVATION AND RECYCLING LA English DT Article DE electroplating; barrel plating; metal plating; NICE3; plating barrel; metal finishing; patented staggered-cell; density plating; energy saving technology; waste minimization technology AB In partnership with the US Department of Energy's Office of Industrial Technology, Whyco Technologies, Inc., has developed an innovative perforated plating barrel used in the plating of metal parts. This new technology employs a thin-walled construction, differing from the traditional thick-wall design required to provide adequate structural integrity. The thicker walls lowered the efficiency of transferring plating solution into and out of the barrel and diminished the electrical current pushed through the holes and onto the parts being plated. By machining pockets out of the traditional thick-walled perforated structure, Whyco produced a 'honeycomb' of staggered cells, allowing for the greatest number of holes per open area while maintaining structural integrity. Hydrodynamic pumping occurs during barrel rotation to create greater solution transfer than in traditional barrels. The Whyco barrel has higher current density plating, which leads to faster plating cycles, reduced bash concentration, and better plating of difficult chemistries such as in alloys. This new technology has helped the company reduce energy use by 16%, eliminate more than 480 tons/year of solid waste, and reduce wastewater by more than 17000 gallons/day. The resulting cost savings total more than $500 000 annually. The company has manufactured and sold more than 275 of these barrels to other electroplating companies that are reporting up to a 40% increase in plating productivity and similar energy and environmental impacts. (C) 2000 ACEEE Published by Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Sullivan, GP (reprint author), Pacific NW Natl Lab, MS K8-07, Richland, WA 99352 USA. NR 0 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-3449 J9 RESOUR CONSERV RECY JI Resour. Conserv. Recycl. PD FEB PY 2000 VL 28 IS 3-4 BP 199 EP 205 DI 10.1016/S0921-3449(99)00044-0 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 282EC UT WOS:000085203000004 ER PT J AU Bozell, JJ Moens, L Elliott, DC Wang, Y Neuenscwander, GG Fitzpatrick, SW Bilski, RJ Jarnefeld, JL AF Bozell, JJ Moens, L Elliott, DC Wang, Y Neuenscwander, GG Fitzpatrick, SW Bilski, RJ Jarnefeld, JL TI Production of levulinic acid and use as a platform chemical for derived products SO RESOURCES CONSERVATION AND RECYCLING LA English DT Article DE levulinic acid; methyltetrahydrofuran; delta-aminolevulinic acid; diphenolic acid; paper sludge; renewables to chemicals; platform chemicals ID DELTA-AMINOLEVULINIC-ACID; 5-AMINOLEVULINIC ACID; AQUEOUS-SOLUTIONS; COMPLEXES; HYDROGENATIONS; PHENOMENOLOGY; DEHYDRATION; CATALYSTS AB Levulinic acid (LA) can be produced cost effectively and in high yield from renewable feedstocks in a new industrial process. The technology is being demonstrated on a I ton/day scale at a facility in South Glens Falls, New York. Low cost LA can be used as a platform chemical for the production of a wide range of value-added products. This research has demonstrated that LA can be converted to methyltetrahydrofuran (MTHF), a solvent and fuel extender. MTHF is produced in >80% molar yield via a single stage catalytic hydrogenation process. A new preparation of delta-aminolevulinic acid (DALA), a broad spectrum herbicide, from LA has also been developed. Each step in this new process proceeds in high (> 80%) yield and affords DALA (as the hydrochloride salt) in > 90% purity, giving a process that could be commercially viable. LA is also being investigated as a starting material for the production of diphenolic acid (DPA), a direct replacement for bisphenol A. (C) 2000 ACEEE Published by Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Bozell, JJ (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Wang, Yong/C-2344-2013 NR 86 TC 365 Z9 393 U1 20 U2 173 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-3449 J9 RESOUR CONSERV RECY JI Resour. Conserv. Recycl. PD FEB PY 2000 VL 28 IS 3-4 BP 227 EP 239 DI 10.1016/S0921-3449(99)00047-6 PG 13 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 282EC UT WOS:000085203000007 ER PT J AU Yashchuk, VV Budker, D Davis, JR AF Yashchuk, VV Budker, D Davis, JR TI Laser frequency stabilization using linear magneto-optics SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 8th International Conference on Ion Sources (ICIS 99) CY SEP 06-10, 1999 CL KYOTO, JAPAN SP Electrochem Soc Japan, Grp Res & Dev Beam Engn, Beam Engn Res Soc Japan ID DIODE-LASER AB The design of a diode laser frequency stabilization system using the Zeeman effect is described. Various regimes of operation are analyzed using the Jones matrix approach. The system is different from the original Joint Institute for Laboratory Astrophysics design in that the magnetic fields are fully contained and thus it can be used in proximity of magnetically sensitive instruments. (C) 2000 American Institute of Physics. [S0034-6748(00)05102-9]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. BP Konstantinov Nucl Phys Inst, Gatchina 188350, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Yashchuk, VV (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Budker, Dmitry/F-7580-2016 OI Budker, Dmitry/0000-0002-7356-4814 NR 13 TC 81 Z9 84 U1 4 U2 18 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 FEB PY 2000 VL 71 IS 2 BP 341 EP 346 DI 10.1063/1.1150205 PN 1 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RE UT WOS:000085115100004 ER PT J AU Harss, B Pardo, RC Rehm, KE Borasi, F Greene, JP Janssens, RVF Jiang, CL Nolen, J Paul, M Schiffer, JP Segel, RE Specht, J Wang, TF Wilt, P Zabransky, B AF Harss, B Pardo, RC Rehm, KE Borasi, F Greene, JP Janssens, RVF Jiang, CL Nolen, J Paul, M Schiffer, JP Segel, RE Specht, J Wang, TF Wilt, P Zabransky, B TI Production of radioactive ion beams using the in-flight technique SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 8th International Conference on Ion Sources (ICIS 99) CY SEP 06-10, 1999 CL KYOTO, JAPAN SP Electrochem Soc Japan, Grp Res & Dev Beam Engn, Beam Engn Res Soc Japan ID FUSION AB Reactions with a heavy projectile incident on a light target can be used for the efficient in-flight production of secondary radioactive beams. An overview of this technique is given using data on F-17 beams produced via the p(O-17, F-17)n and d(O-16, F-17)n reactions. With primary O-16,O-17 beam currents of 100 pnA, intensities of up to 2x10(6) F-17/s on target were achieved. Using this beam, the p(F-17,alpha)O-14 reaction was measured. (C) 2000 American Institute of Physics. [S0034-6748(00)04002-8]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Tech Univ Munich, Phys Dept E12, Munich, Germany. Northwestern Univ, Evanston, IL 60208 USA. RP Harss, B (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 22 TC 69 Z9 69 U1 0 U2 1 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 FEB PY 2000 VL 71 IS 2 BP 380 EP 387 DI 10.1063/1.1150211 PN 1 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RE UT WOS:000085115100010 ER PT J AU Young, DL Coutts, TJ Kaydanov, VI AF Young, DL Coutts, TJ Kaydanov, VI TI Density-of-states effective mass and scattering parameter measurements by transport phenomena in thin films SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 8th International Conference on Ion Sources (ICIS 99) CY SEP 06-10, 1999 CL KYOTO, JAPAN SP Electrochem Soc Japan, Grp Res & Dev Beam Engn, Beam Engn Res Soc Japan ID CD2SNO4 AB A novel machine has been developed to measure transport coefficients in the temperature range of 50-350 K of thin films deposited on electrically insulating substrates. The measured coefficients-resistivity, Hall, Seebeck, and Nernst-are applied to solutions of the Boltzmann transport equation to give information about the film's density-of-states effective mass, the Fermi energy level, and an energy-dependent scattering parameter. The machine is designed to eliminate or compensate for simultaneously occurring transport phenomena that would interfere with the desired measured quantity, while allowing for all four coefficients to be measured on the same sample. An average density-of-states effective mass value of 0.29 +/- 0.04m(e) was measured on the transparent conductive oxide, cadmium stannate (CTO), over a carrier concentration range of 2-7x10(20) cm(-3). This effective mass value matched previous results obtained by optical and thermoelectric modeling. The measured scattering parameter indicates that neutral impurities or a mixture of scattering mechanisms may inhibit the transport of carriers in CTO. (C) 2000 American Institute of Physics. [S0034-6748(00)02802-1]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Colorado Sch Mines, Golden, CO 80401 USA. RP Young, DL (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 22 TC 43 Z9 43 U1 2 U2 20 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 FEB PY 2000 VL 71 IS 2 BP 462 EP 466 DI 10.1063/1.1150224 PN 1 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RE UT WOS:000085115100023 ER PT J AU Edgell, DH Kim, JS Wong, SK Pardo, RC Vondrasek, R AF Edgell, DH Kim, JS Wong, SK Pardo, RC Vondrasek, R TI A one-dimensional axial electron cyclotron resonance source model SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ION-SOURCE; CONFINEMENT AB A conventional zero-dimensional (uniform plasma parameters with no spatial variations) fluid model will provide a good match with an experimental electron cyclotron resonance ion source (ECRIS) charge-state distribution (CSD) if provided with a judicious set of user inputs. However, this arbitrarily chosen set of inputs is not necessarily unique. To be truly predictive, an ECRIS model should rely on experimental parameters as inputs. A multi-species model for an ECRIS plasma using experimental parameters as inputs is under development. The model eliminates electron temperature as a user input by employing a 2 V(v,theta) Fokker-Planck code with an ECR heating term to calculate the non-Maxwellian anisotropic electron distribution function. Further arbitrary user inputs are eliminated in favor of controlled parameters by bounce averaging the Fokker-Planck coefficients for a one-dimensional (1D)/2 V axial model. The neutral gas modeling has been extended to 1D using axially coupled particle balance equations. The improved model is able to reproduce experimental Faraday cup (CSDA) from the Argonne National Laboratory's ECR-II. Further elimination of arbitrary inputs is expected when the ion model is extended to 1D. (C) 2000 American Institute of Physics. [S0034-6748(00)52102-9]. C1 FARTECH Inc, San Diego, CA 92122 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Edgell, DH (reprint author), FARTECH Inc, San Diego, CA 92122 USA. NR 11 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 666 EP 668 DI 10.1063/1.1150254 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700015 ER PT J AU MacGill, RA Vizir, A Brown, IG AF MacGill, RA Vizir, A Brown, IG TI On the use of magnetic buckets for ion beam profile tailoring SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Magnetic multipole plasma confinement geometries employing permanent magnet "buckets" are used extensively for a range of laboratory plasma applications. Among the several consequences for plasma confinement is the important result that the plasma can acquire a more-or-less flat density profile, which when embodied in an ion source, can also lead to a flat profile for the extracted ion beam. For many applications a uniform ion beam current density profile is quite advantageous, for example, for carrying out large-area ion implantation. There are, however, inherent limitations on the extent to which this approach to beam "homogenization" can be utilized, and even for a perfectly flat profile in the immediate postextraction region, the beam will evolve toward Gaussian as it propagates downstream. Here we describe the rare-earth permanent magnet bucket that we have incorporated into our broad-beam vacuum arc ion source, and its effect on the beam profile at the extractor and downstream. The experimental results are compared with a simple model for the beam profile evolution with axial distance. We find that the beam loses memory of its initially flat profile and relaxes to a more-or-less Gaussian shape in a relatively short axial distance similar to w/4 theta, where w is the initial width of the flat beam profile and theta is the beamlet divergence half angle. (C) 2000 American Institute of Physics. [S0034-6748(00)56302-3]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP MacGill, RA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Vizir, Alexey/R-2139-2016 OI Vizir, Alexey/0000-0002-9563-8650 NR 10 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 672 EP 674 DI 10.1063/1.1150256 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700017 ER PT J AU Keidar, M Brown, IG Beilis, II AF Keidar, M Brown, IG Beilis, II TI Axial ion charge state distribution in the vacuum arc plasma jet SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MAGNETIC-FIELD AB We report on our experimental studies of the ion charge state distribution (CSD) of vacuum arc plasmas using a time-of-flight diagnostic method. The dependence of the CSD on the axial distance from the plasma source region was measured for a titanium vacuum arc. It was found that the axial CSD profile is nonuniform. Generally, the mean charge state increases approximately linearly with axial distance from about 1.7 at 12 cm up to 1.9 at 25 cm from the plasma source. A model for ion transport in the free boundary plasma jet is proposed which is based on the existence of an electric field in the quasineutral plasma. This model qualitatively explains the experimental results. (C) 2000 American Institute of Physics. [S0034-6748(00)58302-6]. C1 Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tel Aviv Univ, Elect Discharge & Plasma Lab, IL-69978 Tel Aviv, Israel. RP Keidar, M (reprint author), Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. NR 13 TC 6 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 698 EP 700 DI 10.1063/1.1150265 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700026 ER PT J AU Bugaev, AS Oks, EM Yushkov, GY Anders, A Brown, IG AF Bugaev, AS Oks, EM Yushkov, GY Anders, A Brown, IG TI Enhanced ion charge states in vacuum arc plasmas using a "current spike" method SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MAGNETIC-FIELD; DISTRIBUTIONS AB Ion charge state distributions of vacuum arc ion sources are correlated to the arc operating voltage. An enhancement of ion charge state via an increase of the arc voltage can be achieved utilizing the transient processes that accompany an arc current spike. A current spike of 100-1000 A and several microseconds width was produced on top of the main arc current pulse (100 A, 250 mu s). The ion charge state distribution was measured by charge-to-mass spectrometry. The measured charge state distributions were used as input data to the plasma model of partial local Saha equilibrium, giving the time-dependent electron temperature of the plasma at the freezing zone near the cathode spot. (C) 2000 American Institute of Physics. [S0034-6748(00)56602-7]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, Inst High Current Elect, Tomsk 634050, Russia. State Univ Control Syst & Radioelect, Tomsk 634050, Russia. RP Anders, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Oks, Efim/A-9409-2014; Anders, Andre/B-8580-2009; Yushkov, Georgy/O-8024-2015 OI Oks, Efim/0000-0002-9323-0686; Anders, Andre/0000-0002-5313-6505; Yushkov, Georgy/0000-0002-7615-6058 NR 13 TC 31 Z9 31 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 701 EP 703 DI 10.1063/1.1150266 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700027 ER PT J AU Lee, Y Ji, Q Leung, KN Zahir, N AF Lee, Y Ji, Q Leung, KN Zahir, N TI Nanobeam production with the multicusp ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID BEAMS AB A 1.8-cm-diam multicusp ion source to be used for focused ion beam applications has been tested for Xe, He, Ne, Ar, and Kr ions. The extractable ion and electron currents were measured. The extractable ion current is similar for all these ion species except for Ne+, but the extractable electron current behaves quite differently. The multicusp ion source will be used with a combined extractor-collimator electrode system that can provide a few hundred nA of Xe+ or Kr+ ions. Ion optics computation indicates that these beams can be further focused with an electrostatic column to a beam spot size of similar to 100 nm. (C) 2000 American Institute of Physics. [S0034-6748(00)58402-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Lee, Y (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 4 TC 14 Z9 14 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 722 EP 724 DI 10.1063/1.1150273 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700034 ER PT J AU Kuriyama, M Akino, N Ebisawa, N Grisham, L Hikita, S Honda, A Itoh, T Kawai, M Kazawa, M Kusaka, M Mogaki, K Ohga, T Okumura, Y Oohara, H Satoh, F Seki, H Tanai, Y Toyokawa, Y Umeda, N Usui, K Watanabe, K Yamaguchi, M Yamazaki, H AF Kuriyama, M Akino, N Ebisawa, N Grisham, L Hikita, S Honda, A Itoh, T Kawai, M Kazawa, M Kusaka, M Mogaki, K Ohga, T Okumura, Y Oohara, H Satoh, F Seki, H Tanai, Y Toyokawa, Y Umeda, N Usui, K Watanabe, K Yamaguchi, M Yamazaki, H TI Power flow in the negative-ion based neutral beam injection for JT-60 SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The negative ion based neutral beam injection system for JT-60 has operated since 1996 injecting neutral beam into JT-60 plasmas. A power flow measurement in the beam line and ion source with a water calorimeter had shown that 40%-50% of accelerated beam particles were intercepted on the two accelerator grids and the grounded grid at an ion source gas pressure of 0.2-0.3 Pa. Much of the beam loss was not caused by stripping loss of the negative ions, but rather by direct impingement of the negative ions onto the grids. After reducing the acceleration area by masking the edge area (about 13% of the extraction area) of the accelerator grid so as to minimize the edge effect of magnetic field in the arc chamber, the loss in the accelerator decreased by roughly 25%. In comparing a deuterium beam with a hydrogen beam, the neutral beam power with deuterium is lower by 30% than that of hydrogen at the same arc power, although the heat load onto the grounded grid does not change so much. The power deposition ratios along the beamline were as follows: the beam scraper in the ion source tank and the neutralizer cell received about 3% and about 7%, respectively, of the accelerated beam power, while the ion dumps for both D- and D+ received 20%-30% in total, and 30%-34% reached the neutral beam calorimeter. (C) 2000 American Institute of Physics. [S0034-6748(00)52602-1]. C1 Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 3110193, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Kuriyama, M (reprint author), Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 3110193, Japan. NR 3 TC 17 Z9 18 U1 0 U2 1 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 FEB PY 2000 VL 71 IS 2 BP 751 EP 754 DI 10.1063/1.1150283 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700044 ER PT J AU Kawai, M Grisham, L Itoh, T Kazawa, M Kuriyama, M Mogaki, K Okumura, Y Watanabe, K AF Kawai, M Grisham, L Itoh, T Kazawa, M Kuriyama, M Mogaki, K Okumura, Y Watanabe, K TI Study of plasma uniformity on JT-60U negative ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The negative ion source developed at JAERI for the N-NBI was intended to accelerate a 500 keV, 22 A D(-) beam for 10 s. Two of these ion sources are mounted in the beamline. It has been found that the spatial uniformity of the source plasma is not as good as expected in the design phase of the negative ion sources for JT-60U. The source plasma uniformity has been estimated through measuring spatial distributions of the arc current flowing into each filament group and also the ion saturation current with Langmuir probes placed at ten positions around the extraction area of the plasma grid. We then altered the relative values of the arc current-limiting resistors to the eight filament groups in each source to balance the arc. As a result of the optimization of the arc resistors, the nonuniformity of the source plasma has been reduced. (C) 2000 American Institute of Physics. [S0034-6748(00)57402-4]. C1 Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 3110193, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Kawai, M (reprint author), Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 3110193, Japan. EM kawaim@fusion.naka.jaeri.go.jp NR 2 TC 6 Z9 6 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 755 EP 757 DI 10.1063/1.1150284 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700045 ER PT J AU Moehs, DP Vondrasek, R Pardo, RC Xie, D AF Moehs, DP Vondrasek, R Pardo, RC Xie, D TI ATLAS 10 GHz electron cyclotron resonance ion source upgrade project SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID EXPERIENCE AB A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid coils from the existing ECR will be enclosed in an iron yoke to produce the axial mirror. Based on a current of 500 A, the final model predicts a minimum B field of 3 kG with injection and extraction mirror ratios of 4.4 and 2.9, respectively. (C) 2000 American Institute of Physics. [S0034-6748(00)57502-9]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Berkeley Ion Equipment Inc, Santa Clara, CA 95054 USA. RP Moehs, DP (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 8 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 761 EP 763 DI 10.1063/1.1150286 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700047 ER PT J AU Sherman, JD Bolme, GO Hansborough, LD Hardek, TW Kerstiens, DM Meyer, EA Schneider, JD Smith, HV Stettler, MW Stevens, RR Thuot, ME Zaugg, TJ Arvin, AA Bolt, AS Hegler, PH Richards, MC Boers, JE Kamperschroer, JH Figueroa, TL AF Sherman, JD Bolme, GO Hansborough, LD Hardek, TW Kerstiens, DM Meyer, EA Schneider, JD Smith, HV Stettler, MW Stevens, RR Thuot, ME Zaugg, TJ Arvin, AA Bolt, AS Hegler, PH Richards, MC Boers, JE Kamperschroer, JH Figueroa, TL TI Proton injector operational results on a high-power continuous-wave radio-frequency quadrupole accelerator SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A 50 keV proton injector utilizing a dc microwave source has been used to operate a 1.25 MeV continuous wave (cw) radio-frequency quadrupole (RFQ) accelerator. RFQ injection places stringent requirements on beam properties including centroid control, emittance, and phase-space matching. The ion source chosen for these applications is based on a microwave discharge operating at 2.45 GHz with an on-axis magnetic field near 875 G. The injector employs a space-charge-neutralized, two-solenoid-lens, low-energy beam transport (LEBT) system. Proton injector development with a 1.25 MeV RFQ has resulted in meeting the RFQ 75 mA design current specification in cw mode. Details of the ion source and LEBT operation are presented, and simulations for ion beam extraction and transport are compared with the injector measurements. The proton injector has been converted to 75 keV beam operation for injecting into a 6.7 MeV cw RFQ. (C) 2000 American Institute of Physics. [S0034-6748(00)62402-4]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Savannah River Site, Aiken, SC 29841 USA. Thunderbird Simulat, Garland, TX 75042 USA. Gen Atom Co, San Diego, CA 92121 USA. RP Sherman, JD (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 14 TC 2 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 767 EP 770 DI 10.1063/1.1150288 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700049 ER PT J AU Kwan, JW AF Kwan, JW TI High current injectors for heavy ion driven inertial fusion SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Conceptual heavy ion driven inertial fusion (HIF) drivers typically have an array of up to 100 parallel beams each supplying a beam current of approximate to 0.25 A. According to space-charge limitations in beam extraction and in the low energy beam transport section, there are two options in building injectors for HIF drivers. The traditional way is to use low current density, large aperture, contact ionization sources. The major disadvantage of this approach is the very large size of the injector and matching section. The other option is to use high current density, multiple beamlet ion sources. From various scaling rules, it is found that the multiple beamlet approach is the more attractive one because it can be smaller, and more efficient, although the requirements on the ion source are more demanding. (C) 2000 American Institute of Physics. [S0034-6748(00)59302-2]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Kwan, JW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 807 EP 809 DI 10.1063/1.1150300 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700061 ER PT J AU Brown, I AF Brown, I TI Status of vacuum arc ion sources (invited) (abstract) SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Brown, I (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 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 FEB PY 2000 VL 71 IS 2 BP 826 EP 826 DI 10.1063/1.1150304 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700065 ER PT J AU Anders, A Schein, J Qi, N AF Anders, A Schein, J Qi, N TI Pulsed vacuum-arc ion source operated with a "triggerless" arc initiation method SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Vacuum arcs can be initiated by simply applying a sufficiently high voltage (similar to 1 kV) between the anode and cathode, provided that there is a conducting path between these electrodes. Typically, the conducting path is obtained by coating the ceramic insulator. Plasma is formed explosively at the coating-cathode interface. Since neither a trigger supply nor a trigger electrode are required, the method has been dubbed "triggerless" arc initiation. Triggerless operation of a vacuum arc ion source was demonstrated for a number of cathode materials. It was found that triggerless operation is very reliable as long as the balance of deposition and erosion of the conducting material leads to a steady-state path resistance in the range from 1 Omega to 100 k Omega. (C) 2000 American Institute of Physics. [S0034-6748(00)50002-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Alameda Appl Sci Corp, San Leandro, CA 94577 USA. RP Anders, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 5 TC 22 Z9 23 U1 0 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 FEB PY 2000 VL 71 IS 2 BP 827 EP 829 DI 10.1063/1.1150305 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700066 ER PT J AU Whealton, JH Bacal, M Bruneteau, J Raridon, RJ AF Whealton, JH Bacal, M Bruneteau, J Raridon, RJ TI Increasing the space-charge limit and other effects of cesium seeding in hydrogen negative ion sources SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID VOLUME SOURCES; EXTRACTION; MODEL AB The role of cesium seeding in increasing the negative ion current in volume sources is described. By a reduction in the local plasma potential the current of extracted electrons is vastly reduced. As a result, cesium increases the fraction of the transverse space-charge limit available to the ions by as much as a factor of 3. In addition, cesium can increase the total space-charge limit by injection of Cs+ into the presheath-a newly recognized phenomenon consistent with experimental measurements and determined from application of a Double-Vlasov model for negative ion extraction. (C) 2000 American Institute of Physics. [S0034-6748(00)60002-3]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Ecole Polytech, Phys Milieux Ionises Lab, CNRS, UMR 7648, F-91128 Palaiseau, France. RP Whealton, JH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 872 EP 874 DI 10.1063/1.1150317 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700079 ER PT J AU Beebe, E Alessi, J Bellavia, S Hershcovitch, A Kponou, A Lockey, R Pikin, A Prelec, K Stein, P Kuznetsov, G Tiunov, M AF Beebe, E Alessi, J Bellavia, S Hershcovitch, A Kponou, A Lockey, R Pikin, A Prelec, K Stein, P Kuznetsov, G Tiunov, M TI Status of the Brookhaven National Laboratory high current electron beam ion source test stand SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB As part of a new, compact heavy ion injector for the AGS/RHIC complex at Brookhaven National Laboratory we are developing an electron beam ion source (EBIS) that would satisfy present and future requirements. Such a source should be capable of producing intensities of, e.g., Au35+ ions of about 3x10(9) particles/pulse or U45+ of about 2x10(9) particles/pulse. To achieve this, the required e-beam intensity is 10 A, at a pulse length of 100 ms. An EBIS test stand has been constructed, designed for the full electron beam power and having close to 1/2 of the trap length of an EBIS for RHIC. Initial electron beam tests have resulted in a 50 mu s, 13 A electron beam. Ion production and extraction has been shown with a 3.1 A, 50 ms electron beam, achieving an ion yield of 19 nC/pulse (neutralization degree of 61%); fast extraction trials have yielded extracted ion pulses of 1 mA peak current and 18 mu s at FWHM. Details of the test stand construction, results of the electron beam studies, and properties of the extracted ion pulse are presented. (C) 2000 American Institute of Physics. [S0034-6748(00)60302-7]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. RP Beebe, E (reprint author), Brookhaven Natl Lab, Bldg 930, Upton, NY 11973 USA. NR 7 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 893 EP 895 DI 10.1063/1.1150324 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700086 ER PT J AU Leung, KN AF Leung, KN TI The application and status of the radio frequency driven multi-cusp ion source (invited) SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The multi-cusp ion source has been operated with 2 and 13.5 MHz in either pulse or cw mode for positive or negative ion beam production. Application of this type of source includes spallation neutron source, ion implantation, ion beam lithography, focused ion beam systems, radioactive ion beam production, and neutron generators. In order to achieve long life and reliable operation, different antenna arrangements have been explored. It is found that several antenna configurations can provide over 100 h of rf induction discharge operations. (C) 2000 American Institute of Physics. [S0034-6748(00)51602-5]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Leung, KN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 10 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 1064 EP 1068 DI 10.1063/1.1150387 PN 2 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700136 ER PT J AU Bacal, M Bruneteau, AM Deniset, C Elizarov, LI Sube, F Tontegode, AY Whealton, JH AF Bacal, M Bruneteau, AM Deniset, C Elizarov, LI Sube, F Tontegode, AY Whealton, JH TI Effect of cesium and xenon seeding in negative hydrogen ion sources SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID VOLUME AB It is well known that cesium seeding in volume hydrogen negative ion sources leads to a large reduction of the extracted electron current and in some cases to the enhancement of the negative ion current. The cooling of the electrons due to the addition of this heavy impurity was proposed as a possible cause of the mentioned observations. In order to verify this assumption, we seeded the hydrogen plasma with xenon, which has an atomic weight almost equal to that of cesium. The plasma properties were studied in the extraction region of the negative ion source Camembert III using a cylindrical electrostatic probe while the negative ion relative density was studied using laser photodetachment. It is shown that the xenon mixing does not enhance the negative ion density and leads to the increase of the electron density, while the cesium seeding reduces the electron density. (C) 2000 American Institute of Physics. [S0034-6748(00)50502-4]. C1 Ecole Polytech, Phys Milieux Ionises Lab, CNRS, UMR 7648, F-91128 Palaiseau, France. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Bacal, M (reprint author), Ecole Polytech, Phys Milieux Ionises Lab, CNRS, UMR 7648, F-91128 Palaiseau, France. NR 13 TC 14 Z9 14 U1 0 U2 1 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 FEB PY 2000 VL 71 IS 2 BP 1082 EP 1085 DI 10.1063/1.1150391 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700140 ER PT J AU Brown, IG Monteiro, OR Bilek, MMM Keidar, M Oks, EM Vizir, A AF Brown, IG Monteiro, OR Bilek, MMM Keidar, M Oks, EM Vizir, A TI Some consequences to ion source behavior of high plasma drift velocity SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MODEL AB We consider the case of energetic ion beam formation when the ion streaming velocity within the source plasma is substantial, i.e., when the ions have a drift speed (in the positive downstream direction) that is on the order of or greater than the ion acoustic speed in the plasma. Some interesting consequences can follow, including the capability of a negatively biased substrate located in the plasma stream to maintain high bias voltage, and of an ion source with no extractor or "conventionally poor" extractor providing a kind of plasma immersion ion implantation mode of operation. Here we summarize the kind of plasma geometry in which this situation can occur, and describe some experimental observations we've made of these effects, with reference to a simple theoretical basis for the mechanism. (C) 2000 American Institute of Physics. [S0034-6748(00)65502-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. Cornell Univ, Dept Mech & Aerosp Engn, Ithaca, NY 14853 USA. Russian Acad Sci, Inst High Current Elect, Tomsk 634050, Russia. State Univ Control Syst & Radioelect, Tomsk 634050, Russia. RP Brown, IG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Oks, Efim/A-9409-2014; Vizir, Alexey/R-2139-2016 OI Oks, Efim/0000-0002-9323-0686; Vizir, Alexey/0000-0002-9563-8650 NR 13 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 1086 EP 1089 DI 10.1063/1.1150392 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700141 ER PT J AU Reijonen, J Eardley, M Gough, R Keller, R Leung, K Thomae, R Pickard, D Williams, MD AF Reijonen, J Eardley, M Gough, R Keller, R Leung, K Thomae, R Pickard, D Williams, MD TI Improvement of the lifetime of radio frequency antenna for plasma generation SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB At Lawrence Berkeley National Laboratory different antenna protection schemes have been investigated for the radio frequency-driven multicusp ion source. It was found that the antenna lifetime can be greatly enhanced by an additional shielding, which consists of porcelain, quartz or boron nitride. Different antenna configurations and their influence on the plasma generation will be discussed. Antenna life time greater than 500 hours continuous wave operation has been demonstrated in hydrogen plasma using a novel quartz antenna design. [S0034-6748(00)54202-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Reijonen, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 1 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 1134 EP 1136 DI 10.1063/1.1150407 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700157 ER PT J AU Thomae, R Gough, R Keller, R Leitner, M Leung, K Meyer, D Williams, M AF Thomae, R Gough, R Keller, R Leitner, M Leung, K Meyer, D Williams, M TI Measurements on H- sources for spallation neutron source application SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Lawrence Berkeley National Laboratory is engaged in the development of H- ion sources for the upgrade of the Los Alamos Neutron Science Center (LANSCE) facility and the spallation neutron source (SNS) to be built in the U.S. For the upgrade of the LANSCE facility, the H- ion generator has to deliver an output current of 40 mA. The repetition rate must be 120 Hz at a pulse length of 1 ms (12% duty factor). Furthermore, the normalized emittance must be less than 0.1 pi mm mrad. During the last years, the Ion Beam Technology Group of the LBNL improved the so-called surface conversion source for the generation of higher H- currents. In the first part of this article, we discuss the operation conditions of the source at the required 40 mA output current. The ion source for the 1 MW spallation neutron source is required to provide 35 mA of H- beam current at 6% duty factor (1 ms pulses at 60 Hz) with a normalized rms emittance of less than 0.2 pi mm mrad. The H- beam will be accelerated to 65 keV and matched into a 2.5 MeV RFQ. The ion source is expected to ultimately produce 70 mA of H- at 6% duty factor when the SNS is upgraded to 2 MW of power. For this application, a radio-frequency driven, magnetically filtered multicusp source is being developed at LBNL. Experimental results (including emittance measurements) on the performance of the prototype ion source operated at the demanded beam parameters will be presented in this article. (C) 2000 American Institute of Physics. [S0034- 6748(00)54802-3]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Ruhr Univ Bochum, D-44780 Bochum, Germany. RP Thomae, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 4 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 1213 EP 1215 DI 10.1063/1.1150431 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700181 ER PT J AU Mori, Y Ikegami, K Takagi, A Zelenski, AN Dutto, G Kadantsev, S Levy, CDP Wight, GW Alessi, J Okamura, M AF Mori, Y Ikegami, K Takagi, A Zelenski, AN Dutto, G Kadantsev, S Levy, CDP Wight, GW Alessi, J Okamura, M TI Optically pumped polarized H- ion source for RHIC spin project SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB In the RHIC spin experiment, the high intensity polarized H- ion source is requested. The required 2x10(32)/s cm(2) luminosity in RHIC can be obtained with a 0.5 mA injected H- ion beam intensity. In order to realize such beam intensity, a KEK optically pumped polarized H- ion source is being upgraded at TRIUMF for future installation at RHIC. The first results of polarization measurements are presented here. (C) 2000 American Institute of Physics. [S0034- 6748(00)50602-9]. C1 High Energy Accelerator Res Org, KEK, Tanashi Branch, Tanashi, Tokyo 1880002, Japan. TRIUMF, Vancouver, BC V6T 2A3, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Mori, Y (reprint author), High Energy Accelerator Res Org, KEK, Tanashi Branch, Tanashi, Tokyo 1880002, Japan. NR 7 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2000 VL 71 IS 2 BP 1237 EP 1239 DI 10.1063/1.1150436 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 280RL UT WOS:000085115700187 ER PT J AU Ren, F Han, J Hickman, R Van Hove, JM Chow, PP Klaassen, JJ LaRoche, JR Jung, KB Cho, H Cao, XA Donovan, SM Kopf, RF Wilson, RG Baca, AG Shul, RJ Zhang, L Willison, CG Abernathy, CR Pearton, SJ AF Ren, F Han, J Hickman, R Van Hove, JM Chow, PP Klaassen, JJ LaRoche, JR Jung, KB Cho, H Cao, XA Donovan, SM Kopf, RF Wilson, RG Baca, AG Shul, RJ Zhang, L Willison, CG Abernathy, CR Pearton, SJ TI GaN/AlGaN HBT fabrication SO SOLID-STATE ELECTRONICS LA English DT Article; Proceedings Paper CT Workshop on Wide Bandgap Bipolar Devices CY JAN 24-28, 1999 CL PANAMA CITY BEACH, FLORIDA ID ELECTRONICS; TRANSISTORS; DIODES AB Discrete GaN/AlGaN heterojunction bipolar transistors (HBTs) were fabricated on material grown by both metal organic chemical vapor deposition and molecular beam epitaxy. For both types of material, DC current gains of similar to 10 were achieved in 90 mu m emitter diameter devices measured at 300 degrees C. Some of the key processing steps, such as ohmic contact annealing temperature and mesa fabrication by low damage dry etching, are described, together with secondary ion mass spectrometry measurements of the dopant and background impurity profiles. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SVT Associates Co, Blue Lotus Micro Devices, Eden Prairie, MN 55344 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Bell Labs, Murray Hill, NJ 07974 USA. RP Ren, F (reprint author), Univ Florida, Dept Chem Engn, POB 116005, Gainesville, FL 32611 USA. NR 16 TC 27 Z9 30 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD FEB PY 2000 VL 44 IS 2 BP 239 EP 244 DI 10.1016/S0038-1101(99)00229-4 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 286GC UT WOS:000085434400007 ER PT J AU Simner, SP Hardy, JS Stevenson, JW Armstrong, TR AF Simner, SP Hardy, JS Stevenson, JW Armstrong, TR TI Sintering of lanthanum chromite using strontium vanadate SO SOLID STATE IONICS LA English DT Article DE lanthanum chromite; strontium vanadate; liquid phase sintering; properties ID SYSTEM AB Small proportions (5 and 10 wt.%) of strontium vanadate (Sr-3(VO4)(2)) were added to strontium-doped lanthanum chromite (La0.85Sr0.15CrO5) to produce high density fuel cell interconnect materials in air at 1550 degrees C without adversely affecting the desirable properties of the material. Compositions investigated were shown to have good electrical conductivity at SOFC operating temperatures in air and reducing environments, phase stability from room temperature to 1000 degrees C, negligible thermal expansion mismatch with yttria-stabilized zirconia electrolytes and relatively low dilation at pO(2) 10(-16) atm. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Dept Chem & Mat Sci, Richland, WA 99352 USA. RP Simner, SP (reprint author), Pacific NW Lab, Dept Chem & Mat Sci, MSIN K2-44,902 Battelle Blvd,POB 999, Richland, WA 99352 USA. RI Hardy, John/E-1938-2016 OI Hardy, John/0000-0002-1699-3196 NR 20 TC 33 Z9 36 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD FEB PY 2000 VL 128 IS 1-4 BP 53 EP 63 DI 10.1016/S0167-2738(99)00310-0 PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 292LM UT WOS:000085795800006 ER PT J AU Zacate, MO Minervini, L Bradfield, DJ Grimes, RW Sickafus, KE AF Zacate, MO Minervini, L Bradfield, DJ Grimes, RW Sickafus, KE TI Defect cluster formation in M2O3-doped cubic ZrO2 SO SOLID STATE IONICS LA English DT Article DE zirconia; defects; atomistic simulation; dopants; solid solutions ID SOLID-SOLUTIONS; STABILIZED ZIRCONIA; SIMULATION; EXAFS AB Atomistic simulation calculations based on energy minimization techniques have been used td study the energetics associated with M2O3, solution in ZrO2,. Results predict that the binding energy of an oxygen vacancy to one or two substitutional cations is a strong function of dopant cation radius. Oxygen Vacancies occupy sites that are first neighbour with respect to small dopants whereas oxygen vacancies are located in second neighbour sites with respect to large dopants. The crossover occurs at approximately Sc3+, which also exhibits the smallest binding energy. This behaviour is a consequence of long-range relaxation of the oxygen sublattice. The model is validated by comparing predicted lattice parameters of M2O3:ZrO2 solid solutions with experimental data. (C) 2000 Elsevier Science BN. ALI rights reserved. C1 Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2BP, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87454 USA. RP Grimes, RW (reprint author), Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2BP, England. NR 34 TC 189 Z9 197 U1 5 U2 47 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD FEB PY 2000 VL 128 IS 1-4 BP 243 EP 254 DI 10.1016/S0167-2738(99)00348-3 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 292LM UT WOS:000085795800026 ER PT J AU Waggoner, JR Mansure, AJ AF Waggoner, JR Mansure, AJ TI Development of the downhole dynamometer database SO SPE PRODUCTION & FACILITIES LA English DT Article C1 Sandia Natl Labs, Livermore, CA 94550 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR,, RICHARDSON, TX 75080 USA SN 1064-668X J9 SPE PROD FACIL JI SPE Prod. Fac. PD FEB PY 2000 VL 15 IS 1 BP 3 EP 5 PG 3 WC Engineering, Petroleum SC Engineering GA 287QP UT WOS:000085517500002 ER PT J AU Lao, JY Wang, JH Wang, DZ Yang, SX Tu, Y Wen, JG Wu, HL Ren, ZF Verebelyi, DT Paranthaman, M Aytug, T Christen, DK Bhattacharya, RN Blaugher, RD AF Lao, JY Wang, JH Wang, DZ Yang, SX Tu, Y Wen, JG Wu, HL Ren, ZF Verebelyi, DT Paranthaman, M Aytug, T Christen, DK Bhattacharya, RN Blaugher, RD TI Synthesis and characterization of thallium-based 1212 films with high critical current density on LaAlO3 substrates SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID CU-O SYSTEM; THIN-FILMS; SUPERCONDUCTING TAPES; BULK SUPERCONDUCTIVITY; DEPOSITION AB Growth of epitaxial Cr-doped (TI,Bi)-1212 films on LaAlO3 substrates by pulsed laser deposition (PLD) and post-deposition annealing in static air has been achieved. The films exhibit a high transport J(c) of over 1.5 x 10(6) A cm(-2) at 77 K and self-field. T-c values measured by the four-probe method are in the range 94-100 K. ICP emission spectroscopy measurement shows a thallium deficiency, with about 0.15 atom bismuth per formula in the film. XRD theta-2 theta, phi and omega scans show that the dominant phase is 1212, with excellent epitaxy. The film surface has typical PLD morphology as analysed by SEM. TEM analysis found some inclusions in the film, and HREM found that three 1201 layers exist between the interface of 1212 phase and substrate. C1 SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Lao, JY (reprint author), SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA. RI Ren, Zhifeng/B-4275-2014; Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 22 TC 14 Z9 15 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD FEB PY 2000 VL 13 IS 2 BP 173 EP 177 DI 10.1088/0953-2048/13/2/310 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 287VB UT WOS:000085526200011 ER PT J AU Iyer, AN Lu, W Mironova, M Vipulanandan, C Balachandran, U Salama, K AF Iyer, AN Lu, W Mironova, M Vipulanandan, C Balachandran, U Salama, K TI Current transport and microstructural development in BSCCO tapes and joints fabricated by groove rolling SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID CRITICAL-CURRENT-DENSITY; SUPERCONDUCTING TAPES; GRAIN-BOUNDARIES; PHASE-FORMATION; CORE DENSITY; MICROHARDNESS PROFILES; SHEATHED TAPES; ENHANCEMENT; CONDUCTORS; PB AB The powder-in-tube technique, which includes wire drawing and rolling, has been widely used to fabricate superconducting tapes for possible electric power applications. Ln the present study the starting billet was reduced in size by groove rolling instead of by wire drawing. To optimize the deformation and thermomechanical treatment processes, BSCCO wires of various dimensions were fabricated. The wires were hat rolled to a final thickness of 250 mu m. Short-length tapes were subjected to a series of thermal and deformation steps. Phase development and microstructural development during the process were monitored by XRD, SEM and TEM. Current transport properties of the tapes were determined in the temperature range of 20-77 K in self-field. Thermomechanical treatment resulted in tapes with average critical current densities of 18 000 A cm(-2) at 77 K. High-resolution electron microscopy revealed better texturing and grain structure at the superconductor-silver interface. Superconducting lap- and butt-joints have been formed by a chemical etching technique. Detailed microstructural and current transport properties of the joints have also been measured. C1 Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. NR 32 TC 5 Z9 6 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 EI 1361-6668 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD FEB PY 2000 VL 13 IS 2 BP 187 EP 194 DI 10.1088/0953-2048/13/2/313 PG 8 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 287VB UT WOS:000085526200014 ER PT J AU Komashko, VA Popov, AG Svetchnikov, VL Pronin, AV Melnikov, VS Galkin, AY Pan, VM Snead, CL Suenaga, M AF Komashko, VA Popov, AG Svetchnikov, VL Pronin, AV Melnikov, VS Galkin, AY Pan, VM Snead, CL Suenaga, M TI Critical current density of thin YBCO films on buffered sapphire substrates SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID TRANSPORT CRITICAL CURRENTS; LORENTZ-FORCE DEPENDENCE; SINGLE-CRYSTALLINE; COLUMNAR DEFECTS; OXIDE SUPERCONDUCTORS; PINNING MECHANISMS; YBA2CU3O7-X FILMS; ANISOTROPY; GROWTH AB The critical current density of YBa2Cu3O7-delta films de magnetron sputtered onto buffered (CeO2) sapphire substrates is measured. The peculiarities of these dependences are interpreted by taking into account the crystal defect (edge dislocations) film structure which in turn is determined by the film growth mode. C1 Natl Acad Sci Ukraine, Inst Met Phys, UA-252142 Kiev, Ukraine. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Komashko, VA (reprint author), Natl Acad Sci Ukraine, Inst Met Phys, 36 Vernadsky Blvd, UA-252142 Kiev, Ukraine. NR 21 TC 20 Z9 20 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD FEB PY 2000 VL 13 IS 2 BP 209 EP 214 DI 10.1088/0953-2048/13/2/316 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 287VB UT WOS:000085526200017 ER PT J AU Xie, YY Wu, JZ Aytug, T Gapud, AA Christen, DK Verebelyi, DT Song, KJ AF Xie, YY Wu, JZ Aytug, T Gapud, AA Christen, DK Verebelyi, DT Song, KJ TI Fabrication and physical properties of large-area HgBa2CaCu2O6 superconducting films SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID THIN-FILMS; TEMPERATURE; HGBA2CA2CU3O8+DELTA; LAALO3; GROWTH AB Epitaxial c-axis-orientated HgBa2CaCu2O6 (Hg-1212) superconducting thin films with their dimensions as large as 1/2 inch x 1/2 inch have been recently achieved using a cation-exchange process. Uniformity of the film was studied by slicing samples into eight pieces, on which uniform zero-resistance T-c values above 120 K were observed. In self-field, J(c) values of the film range from 14.6 x 10(6) to 23.7 x 10(6) A cm(-2) at 5 K, 1.77 x 10(6) to 3.85 x 10(6) A cm(-2) at 77 K and 0.54 x 10(6) to 1.38 x 10(6) A cm(-2) at 100 K. The scattering of J(c) is found to be within 44% across the film and could be smaller with improvement of processing. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Xie, YY (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. OI Gapud, Albert/0000-0001-9048-9230 NR 15 TC 10 Z9 10 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD FEB PY 2000 VL 13 IS 2 BP 225 EP 228 DI 10.1088/0953-2048/13/2/318 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 287VB UT WOS:000085526200019 ER EF