FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Yu, SY Brodrick, CW Ryan, MP Scully, JR AF Yu, SY Brodrick, CW Ryan, MP Scully, JR TI Effects of Nb and Zr alloying additions on the activation behavior of Ti in hydrochloric acid SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ANODIC OXIDE-FILMS; CORROSION BEHAVIOR; CHLORIDE SOLUTIONS; PASSIVE BEHAVIOR; HCL SOLUTION; TITANIUM; DISSOLUTION; CR; ELECTROCHEMISTRY; SPECTROSCOPY AB The activation behaviors of air-passivated commercially pure Ti, Ti-50 wt % Zr, and Ti-45 wt % Nb were investigated in hydrochloric acid (HCl) ranging from 0.1 to 10 M, and temperatures ranging from 13 to 52 degrees C. in situ electrochemical impedance spectroscopy and X-ray adsorption studies in 5 M HCl confirmed: (i) oxide dissolution occurred uniformly and (ii) rapid drops in open-circuit potential (OCP) corresponded with the exposure of the underlying metal to solution. Activation energies varied from 56.5 +/- 8, and 62.9 +/- 5, to 103 +/- 6.2 kJ/mol for Ti, Ti-45% Nb, and Ti-50% Zr, respectively. Activation energies, low dissolution rates (<10-7 mol/m(2) s or 10(-3) nm/s) and dependency of the log of the oxide dissolution rate on the log of hydrogen ion activity ranging from 0.4-0.6 suggest that cleavage of metal cation-oxide bonds occurs by a rate-determining ion transfer step involving protonation of O-2 in oxides by one H+ ion to form free OH-. (C) 1999 The Electrochemical Society. S0013-4651(98)11-107-2. All rights reserved. C1 Univ Virginia, Ctr Electrochem Sci & Engn, Charlottesville, VA 22903 USA. Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. RP Yu, SY (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 48 TC 53 Z9 56 U1 6 U2 14 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 DEC PY 1999 VL 146 IS 12 BP 4429 EP 4438 DI 10.1149/1.1392655 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 265PE UT WOS:000084251900017 ER PT J AU Lee, ES DiBartolomeo, DL Selkowitz, SE AF Lee, ES DiBartolomeo, DL Selkowitz, SE TI The effect of venetian blinds on daylight photoelectric control performance SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article AB We investigate how a venetian blind, a common but optically complex fenestration system, contributes to the unreliable performance of daylighting control systems. Using a fully instrumented, full-scale testbed facility, we monitored the daylighting performance of a modified closed-loop proportional photoelectric control system in a private office over the course of a year. The ratio of work-plane illuminance from daylight to photosensor signal is characterized in terms of solar condition and venetian blind angle. Variations in this ratio causes actual illuminance levels to be periodically insufficient. This type of characterization can be used by the installer to determine whether the initial control adjustments made during commissioning will lead to reliable performance under most daylight conditions. Commissioning guidelines are given with caution, based on our observations from this specific case study. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg Technol Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Lee, ES (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg Technol Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 12 TC 19 Z9 19 U1 0 U2 1 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD WIN PY 1999 VL 28 IS 1 BP 3 EP + PG 22 WC Optics SC Optics GA 172BP UT WOS:000078902700001 ER PT J AU Mills, E Borg, N AF Mills, E Borg, N TI Trends in recommended illuminance levels: An international comparison SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article AB This article compares recommended illuminance levels for typical commercial and industrial applications in 19 countries, including offices, classrooms, retail stores, hospitals, and manufacturing activities. The comparison reveals a 5 to 40-fold variation in current-day illuminance levels among countries for a given activity. While much emphasis is placed on energy efficiency as a determinant of lighting energy demand, illuminance levels are also a key factor. Illuminance recommendations have potentially large implications for energy use. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Bldg Sci, Berkeley, CA 94720 USA. RP Mills, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Bldg Sci, Berkeley, CA 94720 USA. NR 27 TC 16 Z9 16 U1 0 U2 5 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD WIN PY 1999 VL 28 IS 1 BP 155 EP + PG 10 WC Optics SC Optics GA 172BP UT WOS:000078902700016 ER PT J AU Nam, SK Lee, BK Zhang, C Kim, ES AF Nam, SK Lee, BK Zhang, C Kim, ES TI Dynamical states of a system due to localized wake forces in a BEPC storage ring SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article AB We examine the dynamical states of a system in the storage ring of the Beijing electron-posit,ron collider (BEPC) by using an extended model with the combination of a constant wake and a delta wake function. The influences of parameters on the stable equilibrium states and the transitions of the states in the BEPC ring are also investigated by using a new extended model with a constant wake function and a delta wake function. C1 Kangweon Natl Univ, Dept Phys, Chunchon 200701, South Korea. Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Nam, SK (reprint author), Kangweon Natl Univ, Dept Phys, Chunchon 200701, South Korea. NR 9 TC 1 Z9 1 U1 0 U2 0 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD DEC PY 1999 VL 35 IS 6 BP 476 EP 481 PG 6 WC Physics, Multidisciplinary SC Physics GA 265PG UT WOS:000084252100004 ER PT J AU Norrish, AE Ferguson, LR Knize, MG Felton, JS Sharpe, SJ Jackson, RT AF Norrish, AE Ferguson, LR Knize, MG Felton, JS Sharpe, SJ Jackson, RT TI Heterocyclic amine content of cooked meat and risk of prostate cancer SO JOURNAL OF THE NATIONAL CANCER INSTITUTE LA English DT Article ID COLON-CANCER; COLORECTAL-CANCER; FRIED FOODS; PRODUCTS; EXPOSURE AB Background: Some epidemiologic studies have described positive associations between prostate cancer risk and meat consumption, but underlying mechanisms have not been identified, Heterocyclic amines are mutagens formed during the cooking of meat. Well-done meat has been associated with increased risks of colorectal and breast cancers in humans. This study; examined associations between prostate cancer risk and 1) estimated daily intake of heterocyclic amines from cooked meat and 2) level of cooked-meat doneness, Methods: A population-based, case-control study involving 317 case patients with prostate cancer and 480 age-matched control subjects was carried out in Auckland, New Zealand, Levels of meat doneness and daily intake of heterocyclic amines were determined from self-reported dietary data and experimentally measured heterocyclic amine levels in locally sourced meat samples cooked under controlled conditions to varying degrees of doneness, Results: The heterocyclic amines found in the highest concentrations in meat samples were 2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]pyri- dine (IFP) and 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) from well-done chicken and pork and very web-done beefsteak. Meat doneness was weakly and inconsistently associated with prostate cancer risk for individual types of meat, but increased risk was observed for web-done beefsteak (relative risk = 1.68; 95% confidence interval = 1.02-2.77; two-sided P for trend = .03). A weak positive gradient of increased risk was associated with estimated daily exposure to IFP but not with the other major heterocyclic amines. Conclusions: Meat doneness and estimated intake of heterocyclic amines from cooked meat were not clearly associated with prostate cancer risk. C1 Univ Auckland, Dept Community Hlth, Auckland 1, New Zealand. Univ Auckland, Auckland Canc Soc Res Ctr, Auckland 1, New Zealand. Univ Auckland, Dept Med, Auckland 1, New Zealand. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Norrish, AE (reprint author), Univ Auckland, Dept Community Hlth, POB 92-019, Auckland 1, New Zealand. RI Ferguson, Lynnette/F-5989-2011 FU NCI NIH HHS [CA55861] NR 27 TC 119 Z9 120 U1 0 U2 5 PU NATL CANCER INSTITUTE PI BETHESDA PA 9030 OLD GEORGETOWN RD, BETHESDA, MD 20814 USA SN 0027-8874 J9 J NATL CANCER I JI J. Natl. Cancer Inst. PD DEC 1 PY 1999 VL 91 IS 23 BP 2038 EP 2044 DI 10.1093/jnci/91.23.2038 PG 7 WC Oncology SC Oncology GA 266ER UT WOS:000084288100016 PM 10580030 ER PT J AU Dykhuizen, RC Smith, MF Gilmore, DL Neiser, RA Jiang, X Sampath, S AF Dykhuizen, RC Smith, MF Gilmore, DL Neiser, RA Jiang, X Sampath, S TI Impact of high velocity cold spray particles SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article DE coating; cold spray; computational; experimental ID CONSTITUTIVE MODEL AB This article presents experimental data and a computational model of the cold spray solid particle impact process. Copper particles impacting onto a polished stainless steel substrate were examined in this study. The high velocity impact causes significant plastic deformation of both the particle and the substrate, but no melting was observed. The plastic deformation exposes clean surfaces that, under the high impact pressures, result in significant bond strengths between the particle and substrate. Experimental measurements of the splat and crater sizes compare well with the numerical calculations. It was shown that the crater depth is significant and increases with impact velocity. However, the splat diameter is much less sensitive to the impact velocity. It was also shown that the geometric lengths of the splat and crater scale linearly with the diameter of the impacting particle. The results presented will allow a better understanding of the bonding process during cold spray. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. SUNY Stony Brook, Dept Mat Sci & Engn, Ctr Thermal Spray Res, Stony Brook, NY 11794 USA. RP Dykhuizen, RC (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 213 Z9 231 U1 6 U2 54 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD DEC PY 1999 VL 8 IS 4 BP 559 EP 564 DI 10.1361/105996399770350250 PG 6 WC Materials Science, Coatings & Films SC Materials Science GA 263ZW UT WOS:000084156000012 ER PT J AU Gilmore, DL Dykhuizen, RC Neiser, RA Roemer, TJ Smith, MF AF Gilmore, DL Dykhuizen, RC Neiser, RA Roemer, TJ Smith, MF TI Particle velocity and deposition efficiency in the cold spray process SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article DE cold spray; deposition; gas dynamic; high velocity; solid state AB Copper powder was sprayed by the cold gas-dynamic method. In-flight particle velocities were measured with a laser two-focus system as a function of process parameters such as gas temperature, gas pressure, and powder feed rate. Mean particle velocities were uniform in a relatively large volume within the plume and agreed with theoretical predictions. The presence of a substrate was found to have no significant effect on in-flight particle velocities prior to impact. Cold-spray deposition efficiencies were measured on aluminum substrates as a function of particle velocity and incident angle of the plume. Deposition efficiencies of up to 95% were achieved, The critical velocity for deposition was determined to be about 640 m/s for the system studied. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Ktech Corp, Albuquerque, NM 87106 USA. RP Gilmore, DL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 11 TC 214 Z9 230 U1 6 U2 62 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD DEC PY 1999 VL 8 IS 4 BP 576 EP 582 DI 10.1361/105996399770350278 PG 7 WC Materials Science, Coatings & Films SC Materials Science GA 263ZW UT WOS:000084156000014 ER PT J AU Williams, TO Aboudi, J AF Williams, TO Aboudi, J TI A fully coupled thermo-mechanical micromechanics model SO JOURNAL OF THERMAL STRESSES LA English DT Article AB The development for a micromechanical model with full thermomechanical coupling, which is based on the combined effects of the mechanical and energy equations, is presented. The model is based on a combined approximate kinematic and thermal analysis of a repenting unit cell in a triply periodic away of inclusions. The unit cell is considered to consist of different subregions that can be composed of any desired material. The behavior of the material within the different subregions can be modeled using elastic, plastic, viscoelastic, viscoplastic, or damage constitutive models. The analysis satisfies the equations of motion and the energy equation for the different subregions of the unit cell in an average sense. The interfacial continuity conditions for the velocities, stresses, temperature, and thermal fluxes between the different subregions are also satisfied in an average sense. Arbitrary heat source terms are included in the energy equation to allow for the analysis of reactive materials. The resulting system of governing equations exhibits full coupling between the deformations and the thermal effects. The proposed model is analytical and provides closed-form expressions for the effective macroscopic kinematic and thermal behavior of a particulate composite. The influence of the thermomechanical coupling on behavior at both the macroscopic and microscopic levels is considered. The presence of the coupling can lend to significant localization of the thermal and deformation responses within different regions of the unit cell. It is shown that the presence of inelastic deformations in conjunction with thermomechanical coupling effects can result in appreciable deviation from an isothermal, inelastic analysis. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Tel Aviv Univ, Fac Engn, Ramat Aviv, Israel. RP Williams, TO (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1643,Mail Stop B216,T-3, Los Alamos, NM 87545 USA. NR 8 TC 6 Z9 6 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0149-5739 J9 J THERM STRESSES JI J. Therm. Stresses PD DEC PY 1999 VL 22 IS 9 BP 841 EP 873 DI 10.1080/014957399280599 PG 33 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 261NA UT WOS:000084014200002 ER PT J AU Kostrikis, LG Neumann, AU Thomson, B Korber, BT McHardy, P Karanicolas, R Deutsch, L Huang, YX Lew, JF McIntosh, K Pollack, H Borkowsky, W Spiegel, HML Palumbo, P Oleske, J Bardeguez, A Luzuriaga, K Sullivan, J Wolinsky, SM Koup, RA Ho, DD Moore, JP AF Kostrikis, LG Neumann, AU Thomson, B Korber, BT McHardy, P Karanicolas, R Deutsch, L Huang, YX Lew, JF McIntosh, K Pollack, H Borkowsky, W Spiegel, HML Palumbo, P Oleske, J Bardeguez, A Luzuriaga, K Sullivan, J Wolinsky, SM Koup, RA Ho, DD Moore, JP TI A polymorphism in the regulatory region of the CC-chemokine receptor 5 gene influences perinatal transmission of human immunodeficiency virus type 1 to African-American infants SO JOURNAL OF VIROLOGY LA English DT Article ID HIV-1 DISEASE PROGRESSION; MACROPHAGE-TROPIC HIV-1; ZIDOVUDINE TREATMENT; DELETION ALLELE; INFECTION; EXPRESSION; RESISTANCE; CCR5-DELTA-32; INDIVIDUALS; CXCR4 AB There are natural mutations in the coding and noncoding regions of the human immunodeficiency virus type I (HIV-1) CC-chemokine coreceptor 5 (CCR5) and in the related CCR2 protein (the CCR2-64I mutation). Individuals homozygous for the CCR5-Delta 32 allele, a which prevents CCR5 expression, strongly resist HIV-1 infection. Several genetic polymorphisms have been identified within the CCR5 5' regulatory region, same of which influence the rate of disease progression in adult AIDS study cohorts. We genotyped 1,442 infants (1,235 uninfected and 207 HIV-1 infected) for five CCR5 and CCR2 polymorphisms: CCR5-59353-T/C, CCR5-59356-C/T CCR5-59402-A/G, CCR5-Delta 32, and CCR2-64I. The clinical significance of each genotype was assessed by measuring whether it influenced the rate of perinatal HIV-1 transmission among 667 AZT-untreated mother-infant pairs (554 uninfected and 113 HIV-1 infected). We found that the mutant CCR5-59356-T allele is relatively common in African-Americans (20.6% allele frequency among 552 infants) and rare in Caucasians and Hispanics (3.4 and 5.6% of 174 and 458 infants, respectively; P < 0.001). There were 38 infants homozygous for CCR5-59356-T, of whom 35 were African-Americans. Among the African-American infants in the AZT-untreated group? there was a highly significant increase in HIV-1 transmission to infants with two mutant CCR5-59356-T alleles (47.6% of 21), compared to those with no or one mutant allele (13.4 to 14.1% of 187 and 71, respectively; P < 0.001). The increased relative risk was 5.9 (95% confidence interval, 2.3 to 15.3; P < 0.001). The frequency of the CCR5-59356-T mutation varies between population groups in the United States, a low frequency occurring in Caucasians and a higher frequency occurring in African-Americans. Homozygosity for CCR5-59356-T is strongly associated with an increased rate of perinatal HIV-1 transmission. C1 Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. NYU Med Ctr, New York, NY 10016 USA. Bar Ilan Univ, Fac Life Sci, Ramat Gan, Israel. Clin Trials & Surveys Corp, Baltimore, MD USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. NIAID, Div AIDS, Bethesda, MD 20892 USA. Harvard Univ, Sch Med, Dept Pediat, Boston, MA 02115 USA. Univ Massachusetts, Sch Med, Worcester, MA USA. Univ Med & Dent New Jersey, Sch Med, Dept Pediat, Newark, NJ 07103 USA. Northwestern Univ, Sch Med, Dept Med, Chicago, IL 60611 USA. Univ Texas, SW Med Ctr, Dept Med, Dallas, TX USA. RP Kostrikis, LG (reprint author), Rockefeller Univ, Aaron Diamond AIDS Res Ctr, 455 1st Ave, New York, NY 10016 USA. RI Wolinsky, Steven/B-2893-2012; Kostrikis, Leondios/A-5330-2016; OI Kostrikis, Leondios/0000-0002-5340-7109; Wolinsky, Steven/0000-0002-9625-6697; Korber, Bette/0000-0002-2026-5757 FU NIAID NIH HHS [N01AI85339, N01-AI85339, R01 AI041420, R01 AI41420, R01 AI43868, U01 AI034841, U01 AI034858] NR 42 TC 102 Z9 104 U1 1 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0022-538X J9 J VIROL JI J. Virol. PD DEC PY 1999 VL 73 IS 12 BP 10264 EP 10271 PG 8 WC Virology SC Virology GA 255ZD UT WOS:000083699300066 PM 10559343 ER PT J AU Robinson, AC Robinson, DW AF Robinson, AC Robinson, DW TI A best approximation evaluation of a finite element calculation SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT 7th Conference of the International-Linear-Algebra-Society in Honor of Hans Schneider CY JUN 03-06, 1998 CL MADISON, WISCONSIN SP Int Linear Algebra Soc DE best approximation; matrix inversion; computational quality AB We discuss an electrostatics problem whose solution must lie in the set S of all real n-by-n symmetric matrices with all row sums equal to zero. With respect to the Frobenius norm, we provide an algorithm that finds the member of S which is closest to any given n-by-n matrix, and determines the distance between the two. This algorithm makes it practical to find the distances to S of finite element approximate solutions of the electrostatics problem, and to reject those which are not sufficiently close. (C) 1999 Elsevier Science Inc. All rights reserved. AMS classification: 15A09; 65N15. C1 Brigham Young Univ, Dept Math, Provo, UT 84602 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Robinson, DW (reprint author), Brigham Young Univ, Dept Math, Provo, UT 84602 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD DEC 1 PY 1999 VL 303 BP 367 EP 375 PG 9 WC Mathematics, Applied; Mathematics SC Mathematics GA 268FJ UT WOS:000084403400023 ER PT J AU Bodart, PR Amoureux, JP Pruski, M Bailly, A Fernandez, C AF Bodart, PR Amoureux, JP Pruski, M Bailly, A Fernandez, C TI Applications of Al-27 multiple quantum magic angle spinning NMR to aluminophosphate molecular sieves SO MAGNETIC RESONANCE IN CHEMISTRY LA English DT Article DE NMR; (27)AL NMR; MQMAS; CP-MQMAS; MQ-REDOR; ALPO; aluminophosphate molecular sieves ID MAS-NMR; QUADRUPOLAR NUCLEI; CROSS-POLARIZATION; SPIN-1/2 NUCLEI; RESOLUTION; SPECTRA; TRIPLE; SPECTROSCOPY; DIFFRACTION; HYDRATION AB The advantages and drawbacks of various techniques that utilize multiple quantum magic angle spinning (MQMAS) NMR for studying molecular sieves and related materials are reviewed. The techniques include z-filtered MQMAS with rotor synchronization, MQMAS with cross-polarization and MQMAS with REDOR. Several methods of recovering quantitative intensities in MQMAS spectra are discussed. Examples of applications include studies of various types of aluminophosphate. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Scvi & Technol Lille, LDSMM, F-59655 Villeneuve Dascq, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Caen, ISMRA, F-14050 Caen, France. RP Amoureux, JP (reprint author), Univ Scvi & Technol Lille, LDSMM, F-59655 Villeneuve Dascq, France. RI fernandez, christian/C-3158-2008 OI fernandez, christian/0000-0002-5476-3148 NR 32 TC 12 Z9 12 U1 1 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0749-1581 J9 MAGN RESON CHEM JI Magn. Reson. Chem. PD DEC PY 1999 VL 37 SI SI BP S69 EP S74 DI 10.1002/(SICI)1097-458X(199912)37:133.0.CO;2-8 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 265FQ UT WOS:000084232000011 ER PT J AU Hetherington, HP Telang, F Pan, JW Sammi, M Schuhlein, D Molina, P Volkow, ND AF Hetherington, HP Telang, F Pan, JW Sammi, M Schuhlein, D Molina, P Volkow, ND TI Spectroscopic imaging of the uptake kinetics of human brain ethanol SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE NMR spectroscopy; brain; blood; alcohol; visibility ID MAGNETIC-RESONANCE SPECTROSCOPY; H-1 SPECTROSCOPY; RABBIT BRAIN; INVIVO; METABOLITES; ALCOHOL; RELAXATION AB Previous measurements of the ratio of brain to Venous blood alcohol have ranged from 21-100%, depending on the experimental model, pulse sequence, and the concentration reference used. The goal of this study was to evaluate the uptake kinetics and visibility of brain ethanol in comparison to Venous blood levels using a pulse sequence that minimizes uncertainties due to differences in J-modulation, T-1, and T-2 between ethanol and the concentration standard. This was achieved using a short TE (24 msec) spin echo sequence with a semiselective refocusing pulse to minimize J-modulation losses of the ethanol. Brain ethanol levels were measured with 10-min time resolution using a 16 x 16 spectroscopic imaging matrix with nominal voxels of 1.44 cc. During the course of the study, the brain/blood alcohol ratio declined from a Value of 1.54 +/- 0.74 at 35 min after drinking to a final Value of 0.93 +/- 0.16 at 85 min postdrinking. (C) 1999 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. N Shore Univ Hosp, Dept Surg, Manhasset, NY 11030 USA. RP Hetherington, HP (reprint author), Brookhaven Natl Lab, Dept Med, Rm 5-35,Bldg 490, Upton, NY 11973 USA. NR 29 TC 18 Z9 18 U1 0 U2 1 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 DEC PY 1999 VL 42 IS 6 BP 1019 EP 1026 DI 10.1002/(SICI)1522-2594(199912)42:6<1019::AID-MRM5>3.0.CO;2-Y PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 260PP UT WOS:000083959300005 PM 10571922 ER PT J AU Shen, J Rothman, DL Hetherington, HP Pan, JW AF Shen, J Rothman, DL Hetherington, HP Pan, JW TI Linear projection method for automatic slice shimming SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE automatic shimming; spectroscopic imaging; B-0 inhomogeneity; phase mapping ID MAGNETIC-FIELD; INVIVO; IMPROVEMENTS; ADJUSTMENT; BRAIN AB A fast, reliable automatic slice shimming method is described. In-slice shim adjustments are based on one-dimensional phase mapping of four in-slice linear projections through the slice center. For axial, coronal, and sagittal slices it is shown that all in-slice first-, second-, and third-order spherical harmonic terms of Bo inhomogeneity can be unequivocally determined and corrected. Through-slice shim adjustment is achieved using a one-dimensional projection of the entire slice or ROI along the slice-selection direction. Applications of this method to single-slice in vivo spectroscopic imaging of human brain have resulted in reproducible, high quality spectroscopic data. (C) 1999 Wiley-Liss, Inc. C1 Nathan S Kline Inst Psychiat Res, Ctr Adv Brain Imaging, Orangeburg, NY 10962 USA. NYU, Sch Med, Dept Radiol, New York, NY USA. NYU, Sch Med, Dept Psychiat, New York, NY USA. Yale Univ, Sch Med, Dept Diagnost Radiol, New Haven, CT USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Shen, J (reprint author), Nathan S Kline Inst Psychiat Res, Ctr Adv Brain Imaging, 140 Old Orangeburg Rd, Orangeburg, NY 10962 USA. FU NINDS NIH HHS [R29-NS32126, R01-NS37527] NR 13 TC 28 Z9 29 U1 2 U2 6 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 DEC PY 1999 VL 42 IS 6 BP 1082 EP 1088 DI 10.1002/(SICI)1522-2594(199912)42:6<1082::AID-MRM12>3.0.CO;2-G PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 260PP UT WOS:000083959300012 PM 10571929 ER PT J AU Rouquier, S Stubbs, L Gaillard-Sanchez, I Giorgi, D AF Rouquier, S Stubbs, L Gaillard-Sanchez, I Giorgi, D TI Sequence and chromosomal localization of the mouse ortholog of the human olfactory receptor gene 912-93 SO MAMMALIAN GENOME LA English DT Article ID HUMAN GENOME; FAMILY; MEMBERS C1 CNRS, IPR 1142, IGH, F-34396 Montpellier 5, France. Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, Livermore, CA 94550 USA. INRA, F-34000 Montpellier, France. RP Gaillard-Sanchez, I (reprint author), CNRS, IPR 1142, IGH, Rue Cardonille, F-34396 Montpellier 5, France. OI Stubbs, Lisa/0000-0002-9556-1972 NR 18 TC 7 Z9 8 U1 1 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-8990 J9 MAMM GENOME JI Mamm. Genome PD DEC PY 1999 VL 10 IS 12 BP 1172 EP 1174 DI 10.1007/s003359901185 PG 3 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 259XZ UT WOS:000083920400010 PM 10594242 ER PT J AU Covino, BS Bullard, SJ Holcomb, GR Russell, JH Cramer, SD Bennett, JE Laylor, HM AF Covino, BS Bullard, SJ Holcomb, GR Russell, JH Cramer, SD Bennett, JE Laylor, HM TI Chemically modified thermal-spray zinc anodes for galvanic cathodic protection (Reprinted) SO MATERIALS PERFORMANCE LA English DT Reprint AB Humectants, substances that promote the retention of moisture, were applied to new and previously aged thermal-sprayed Zn anodes to Improve the performance of galvanic cathodic protection systems. Anodes on steel-reinforced concrete were treated with aqueous solutions of the humectants lithium nitrate (LiNO3) and lithium bromide (LiBr). LiBr was the most beneficial humectant, increasing the average galvanic current density of new thermal-sprayed Zn anodes by as much as a factor of six. C1 US Dept Energy, Albany Res Ctr, Albany, OR 97321 USA. JE Bennett Consulting Inc, Chardon, OH 44024 USA. Oregon Dept Transportat, Salem, OR 97301 USA. RP Covino, BS (reprint author), US Dept Energy, Albany Res Ctr, 1450 Queen Ave SW, Albany, OR 97321 USA. RI Holcomb, Gordon/G-9070-2013 OI Holcomb, Gordon/0000-0003-3542-5319 NR 8 TC 2 Z9 2 U1 0 U2 1 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0094-1492 J9 MATER PERFORMANCE JI Mater. Perform. PD DEC PY 1999 VL 38 IS 12 BP 28 EP 32 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA 328KQ UT WOS:000087850400013 ER PT J AU Fryxell, GE Liu, J Mattigod, S AF Fryxell, GE Liu, J Mattigod, S TI Self-assembled monolayers on mesoporous supports (SAMMS) - an innovative environmental sorbent SO MATERIALS TECHNOLOGY LA English DT Article C1 Pacific NW Lab, Richland, WA 99352 USA. RP Fryxell, GE (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 0 TC 14 Z9 14 U1 0 U2 2 PU MATRICE TECHNOLOGY LIMITED PI POULTON PA PO BOX 41, POULTON FY6 8GD, ENGLAND SN 1066-7857 J9 MATER TECHNOL JI Mater. Technol. PD DEC PY 1999 VL 14 IS 4 BP 188 EP 191 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 319PN UT WOS:000087350500003 ER PT J AU Boyd, S Carr, R AF Boyd, S Carr, R TI A new bound for the ratio between the 2-matching problem and its linear programming relaxation SO MATHEMATICAL PROGRAMMING LA English DT Article DE 2-matching; traveling salesman problem; subtour elimination problem; polyhedral combinatorics ID TSP AB Consider the 2-matching problem defined on the complete graph, with edge costs which satisfy the triangle inequality. We prove that the value of a minimum cost 2-matching is bounded above by 4/3 times the value of its linear programming relaxation, the fractional 2-matching problem. This lends credibility to a long-standing conjecture that the optimal value for the traveling salesman problem is bounded above by 4/3 times the value of its linear programming relaxation, the subtour elimination problem. C1 Univ Ottawa, Dept Comp Sci, Ottawa, ON, Canada. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Boyd, S (reprint author), Univ Ottawa, Dept Comp Sci, Ottawa, ON, Canada. NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-5610 J9 MATH PROGRAM JI Math. Program. PD DEC PY 1999 VL 86 IS 3 BP 499 EP 514 DI 10.1007/s101070050102 PG 16 WC Computer Science, Software Engineering; Operations Research & Management Science; Mathematics, Applied SC Computer Science; Operations Research & Management Science; Mathematics GA 273HN UT WOS:000084702000004 ER PT J AU Mason, TA Maudlin, PJ AF Mason, TA Maudlin, PJ TI Effects of higher-order anisotropic elasticity using textured polycrystals in three-dimensional wave propagation problems SO MECHANICS OF MATERIALS LA English DT Article DE third-order elasticity; anisotropic elasticity; wave propagation; crystallographic texture ID CONSTANTS; MICROSCOPY; PLASTICITY; AGGREGATE AB Increasingly, more precise analysis of components in complicated systems is required to better understand material behavior under high strain-rate deformation; Applications such as warhead/target interactions and crash-worthiness testing are typical examples, Historically, in order to keep these analyses tractable, only a minimal description of the material behavior was included by simplifying the material characterization down to just a few parameters. Recent works have focused on including a greater degree of information regarding the micro- and meso-structure of polycrystals in the modeling of material behavior under a variety of loading conditions. One of the first steps in this effort is the inclusion of a material's crystallographic texture into the estimation of elastic properties. An additional step is the extension of the constitutive modeling to include anisotropic non-linear elastic behavior. Both of these steps are undertaken here in terms of third-order elastic stiffness tensors, as determined for various single crystal and polycrystal test materials of interest, and applied in three-dimensional (3-D) FEM simulation of the collapse of hemispherical shells. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Mason, TA (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663,Mail Stop G755, Los Alamos, NM 87545 USA. NR 43 TC 10 Z9 10 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD DEC PY 1999 VL 31 IS 12 BP 861 EP 882 DI 10.1016/S0167-6636(99)00030-7 PG 22 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA 260PD UT WOS:000083958300005 ER PT J AU Cahn, RN Cederstrom, B Danielsson, M Hall, A Lundqvist, M Nygren, D AF Cahn, RN Cederstrom, B Danielsson, M Hall, A Lundqvist, M Nygren, D TI Detective quantum efficiency dependence on x-ray energy weighting in mammography SO MEDICAL PHYSICS LA English DT Article DE mammography; DQE; energy weighting; single-photon counting ID DQE; SPECTRUM; NOISE; SNR AB An evaluation of the dependence of detective quantum efficiency (DQE) on the incident energy spectrum has been made for mammography. The DQE dependence on the energy spectrum has been evaluated for energy-integrating detectors, photon-counting detectors, and detectors that measure the energy of each photon. To isolate the effect of the x-ray energy spectrum the detector has been assumed to be ideal, i.e., all noise sources are assumed to be zero except for quantum fluctuations. The result shows that the improvement in DQE, if the energy-integrating detector is compared to a single-photon counting detector, is of the order of 10%. Comparing the energy-integrating detector and the detector measuring the energy for each photon the improvement is around 30% using a molybdenum anode spectrum typical in mammography. It is shown that the optimal weight factors to combine the data in the case the energy is measured are very well approximated if the weight factors are proportional to E-3. Another conclusion is that in calculating the DQE, a detector should be compared to one that uses ideal energy weighting for each photon since this provides the best signal-to-noise ratio. This has generally been neglected in the literature. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)01312-7]. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94707 USA. Royal Inst Technol, S-10405 Stockholm, Sweden. RP Cahn, RN (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94707 USA. NR 13 TC 100 Z9 100 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD DEC PY 1999 VL 26 IS 12 BP 2680 EP 2683 DI 10.1118/1.598807 PG 4 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 267LJ UT WOS:000084359200022 PM 10619253 ER PT J AU Gall, K Yang, N Horstemeyer, M McDowell, DL Fan, JH AF Gall, K Yang, N Horstemeyer, M McDowell, DL Fan, JH TI The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID ALUMINUM-ALLOYS; BEHAVIOR; GROWTH; LIFE; INITIATION; DEFECTS; CRACKS AB Constant-amplitude high-cycle fatigue tests (sigma(max) = 133 MPa, sigma(max)/sigma(y) = 0.55, and R = 0.1) were conducted on cylindrical samples machined from a cast A356-T6 aluminum plate: The fracture surface of the sample with the smallest fatigue-crack nucleating defect was examined using a scanning electron microscope (SEM). For low crack-tip driving forces (fatigue-crack growth rates of da/dN < 1 x 10(-7) m/cycle), we discovered that a small semicircular surface fatigue crack propagated primarily through the Al-1 pct Si dendrite cells. The silicon particles in the eutectic remained intact and served as barriers at low fatigue-crack propagation rates. When the semicircular fatigue crack inevitably crossed the three-dimensional Al-Si eutectic network, it propagated primarily along the interface between the silicon particles and the Al-1 pct Si matrix. Furthermore, nearly all of the silicon particles were progressively debonded by the fatigue cracks propagating at low rates, with the exception of elongated particles with a major axis perpendicular to the crack plane, which were fractured. As the fatigue crack grew with a high crack-tip driving force (fatigue-crack growth rates of da/dN > 1 x 10(-6) m/cycle), silicon particles ahead of the crack tip were fractured, and the crack subsequently propagated through the weakest distribution of prefractured particles in the Al-Si eutectic. Only small rounded silicon particles were observed to debond while the fatigue crack grew at high rates. Using fracture-surface markings and fracture mechanics, a macroscopic measure of the maximum critical driving force between particle debonding vs fracture during fatigue-crack growth was calculated to be approximately K-max(tr) approximate to 6.0 MPa root m for the present cast A356 alloy. C1 Univ Colorado, Dept Engn Mech, Boulder, CO 80309 USA. Sandia Natl Labs, Mat & Engn Sci Ctr, Livermore, CA 94550 USA. Georgia Inst Technol, GWW Sch Mech Engn, Atlanta, GA 30332 USA. RP Gall, K (reprint author), Univ Colorado, Dept Engn Mech, Boulder, CO 80309 USA. OI Horstemeyer, Mark/0000-0003-4230-0063 NR 31 TC 89 Z9 96 U1 1 U2 15 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD DEC PY 1999 VL 30 IS 12 BP 3079 EP 3088 DI 10.1007/s11661-999-0218-2 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 269DK UT WOS:000084460900005 ER PT J AU Choi, JH Sung, C Shin, KH Allard, LF AF Choi, JH Sung, C Shin, KH Allard, LF TI Elemental segregation in Co-Cr-P-Pt/Cr magnetic thin films by imaging filter SO METALS AND MATERIALS-KOREA LA English DT Article DE high resolution transmission electron microscopy (HRTEM); energy filter; compositional segregation; elemental mapping ID DENSITY AB The microstructure and magnetic properties of the Co-Cr-P-Pt thin films with Cr underlayer used in longitudinal magnetic recording were characterized as a function of Pt content from 0 to 18.8 at.% Pt. The effects of platinum addition in the Co-Cr-P-Pt system on microstructural features were investigated and related to changes of magnetic properties of thin films. The increase of in-plane coercivity may be related to the segregations at the grain boundary and to the changes of other microstructural features. These changes in magnetic properties were elucidated by TEM equipped with energy dispersive x-ray spectroscopy (EDS) and Gatan Image Filter (GIF(TM)). C1 Univ Massachusetts, Ctr Adv Mat, Lowell, MA 01854 USA. Korea Inst Sci & Technol, Div Met, Seongbuk Ku, Seoul 136791, South Korea. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Choi, JH (reprint author), Univ Massachusetts, Ctr Adv Mat, Lowell, MA 01854 USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU KOREAN INST METALS MATERIALS PI SEOUL PA POSCO CENTER, 4TH FL (EAST WING), 892 DAECHI-4-DONG, KANGNAM-KU, SEOUL 135-777, SOUTH KOREA SN 1225-9438 J9 MET MATER-KOREA JI Met. Mater.-Korea PD DEC PY 1999 VL 5 IS 6 BP 551 EP 554 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 271DF UT WOS:000084578300008 ER PT J AU Roy, AK Fleming, DL Freeman, DC Lum, BY AF Roy, AK Fleming, DL Freeman, DC Lum, BY TI Stress corrosion cracking of alloy C-22 and Ti Gr-12 using double-cantilever-beam technique SO MICRON LA English DT Review DE stress corrosion cracking; double-cantilever-beam specimen; nickel-base alloy; titanium alloy; stress intensity factor; scanning electron microscopy AB Susceptibility to stress corrosion cracking (SCC) of two candidate alloys for the inner container of the multi-barrier nuclear waste package was evaluated by using wedge-loaded precracked double-cantilever-beam (DCB) specimens in deaerated acidic brine (pH approximate to 2.70) at 90 degrees C. Materials tested included Alloy C-22 and Ti Grade-12. Duplicate samples of each material were loaded at different initial stress intensity factor (K-I) values ranging between 22 and 43 MPa root m. Both metallography and the compliance methods were used to determine the final crack length. The final stress intensity for SCC (Kf) was computed from the measured final wedge load and the average crack length. The results indicate that, in general, the final crack lengths measured by metallography and compliance agreed well with one another, thus, providing very similar K-f values. The alloy C-22 showed higher susceptibility to SCC than Ti Grade-12 in terms of the average crack growth. Fractographic evaluation by scanning electron microscopy (SEM) of broken DCB, specimens revealed three distinct regions showing the characteristics of fatigue precrack, SCC, and fast fracture. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 LLNL, Framatome Cogema Fuels, Livermore, CA 94550 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Roy, AK (reprint author), LLNL, Framatome Cogema Fuels, 7000 E Ave,M-S L-369, Livermore, CA 94550 USA. NR 5 TC 5 Z9 5 U1 4 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0968-4328 J9 MICRON JI Micron PD DEC PY 1999 VL 30 IS 6 BP 649 EP 654 DI 10.1016/S0968-4328(99)00037-2 PG 6 WC Microscopy SC Microscopy GA 245NK UT WOS:000083114900007 ER PT J AU Natarajan, A Wang, W Ma, E Bhattacharya, RN Blaugher, RD AF Natarajan, A Wang, W Ma, E Bhattacharya, RN Blaugher, RD TI Development of a micromachining process for the fabrication of a superconductor magnetic-field sensor SO MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS LA English DT Article ID CA-CU-O; ELECTRODEPOSITION PROCESS; THIN-FILMS; OXIDE AB This paper reports an effort to introduce high temperature superconductor (HTS) into the MEMS (microelectromechanical systems) held, to develop fabrication procedures suitable for HTS, and using them to fabricate a prototype superconductor microsensor for magnetic field detection. The prototype device fabricated is a sensor based on the giant magnetoresistivity of a high temperature superconductor around its critical temperature. It was fabricated using optical lithography and electrodeposition of Tl1Ba2Ca2Cu3Ox (Tl-1223) type high Te superconductors. The test results of the prototype sensor fabricated show that the prototype sensor has a very high magnetoresistivity at medium to strong magnetic field strength and low magnetoresistivity at weak magnetic field. Our work suggests that in order to develop a high precision magnetic sensor for the detection of very weak magnetic fields, other HTS materials with less flux pinning effect and more weak links need to be pursued. The MEMS fabrication process developed is simple, repeatable, and applicable to microfabrication of other types of superconductor devices. C1 Louisiana State Univ, Dept Mech Engn, Microsyst Engn Team Mu SET, Baton Rouge, LA 70803 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Louisiana State Univ, Dept Mech Engn, Microsyst Engn Team Mu SET, Baton Rouge, LA 70803 USA. RI Ma, En/A-3232-2010 NR 17 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0946-7076 EI 1432-1858 J9 MICROSYST TECHNOL JI Microsyst. Technol. PD DEC PY 1999 VL 6 IS 2 BP 67 EP 72 DI 10.1007/s005420050177 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 272TN UT WOS:000084667200005 ER PT J AU Bogush, ML Velikodvorskaya, TV Lebedev, YB Nikolaev, LG Lukyanov, SA Fradkov, AF Pliyev, BK Boichenko, MN Usatova, GN Vorobiev, AA Andersen, GL Sverdlov, ED AF Bogush, ML Velikodvorskaya, TV Lebedev, YB Nikolaev, LG Lukyanov, SA Fradkov, AF Pliyev, BK Boichenko, MN Usatova, GN Vorobiev, AA Andersen, GL Sverdlov, ED TI Identification and localization of differences between Escherichia coli and Salmonella typhimurium genomes by suppressive subtractive hybridization SO MOLECULAR AND GENERAL GENETICS LA English DT Article DE Escherichia coli; Salmonella typhimurium; subtractive hybridization ID POLYMERASE CHAIN-REACTION; COENZYME-A SYNTHETASE; LIPOPOLYSACCHARIDE CORE; NEISSERIA-MENINGITIDIS; GENETIC-DIFFERENCES; SEQUENCE; PROTEIN; K-12; DNA; PURIFICATION AB The availability of bacterial genome sequences raises an important new problem - how can one move from completely sequenced microorganisms as a reference to the hundreds and thousands of other strains or isolates of the same or related species that will not be sequenced in the near future? An efficient way to approach this task is the comparison of genomes by subtractive hybridization. Recently we developed a sensitive and reproducible subtraction procedure for comparison of bacterial genomes, based on the method of suppression subtractive hybridization (SSH). In this work we demonstrate the applicability of subtractive hybridization to the comparison of the related but markedly divergent,bacterial species Escherichia coli and Salmonella typhimurium. Clone libraries representing sequence differences were obtained and, in the case of completely sequenced E. coli genome, the differences were directly placed in the genome map. About 60% of the differential clones identified by SSH were present in one of the genomes under comparison and absent from the other. Additional differences in most cases represent sequences that have diverged considerably in the course of evolution. Such an approach to comparative bacterial genomics can be applied both to studies of interspecies evolution - to elucidate the "strategies" that enable different genomes to fit their ecological niches - and to development of diagnostic probes for the rapid identification of pathogenic bacterial species. C1 Russian Acad Sci, Shemyakin Ovchinnikov Inst Bioorgan Chem, Moscow 117871, Russia. IM Sechenov Med Acad, Dept Microbiol, Moscow 119435, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Sverdlov, ED (reprint author), Russian Acad Sci, Shemyakin Ovchinnikov Inst Bioorgan Chem, Moscow 117871, Russia. RI Nikolaev, Lev/J-1666-2012; Lebedev, Yuri/G-6738-2012; Lukyanov, Sergey/F-9140-2014; Andersen, Gary/G-2792-2015 OI Lebedev, Yuri/0000-0003-4554-4733; Andersen, Gary/0000-0002-1618-9827 NR 43 TC 31 Z9 41 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0026-8925 J9 MOL GEN GENET JI Mol. Gen. Genet. PD DEC PY 1999 VL 262 IS 4-5 BP 721 EP 729 PG 9 WC Biochemistry & Molecular Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Genetics & Heredity GA 269EL UT WOS:000084463700014 PM 10628854 ER PT J AU Spiro, C Pelletier, R Rolfsmeier, ML Dixon, MJ Lahue, RS Gupta, G Park, MS Chen, X Mariappan, SVS McMurray, CT AF Spiro, C Pelletier, R Rolfsmeier, ML Dixon, MJ Lahue, RS Gupta, G Park, MS Chen, X Mariappan, SVS McMurray, CT TI Inhibition of FEN-1 processing by DNA secondary structure at trinucleotide repeats SO MOLECULAR CELL LA English DT Article ID SACCHAROMYCES-CEREVISIAE; MISMATCH REPAIR; CTG REPEATS; HUNTINGTON DISEASE; ESCHERICHIA-COLI; IN-VITRO; YEAST; REPLICATION; INSTABILITY; EXPANSION AB The mechanism by which trinucleotide expansion occurs in human genes is not understood. However, it has been hypothesized that DNA secondary structure may actively participate by preventing FEN-1 cleavage of displaced Okazaki fragments. We show here that secondary structure can, indeed, play a role in expansion by a FEN-1-dependent mechanism. Secondary structure inhibits flap processing at GAG, CGG, or CTG repeats in a length-dependent manner by concealing the 5' end of the flap that is necessary for both binding and cleavage by FEN-1. Thus, secondary structure can defeat the protective function of FEN-1, leading to site-specific expansions. However, when FEN-1 is absent from the cell, alternative pathways to simple inhibition of flap processing contribute to expansion. C1 Mayo Clin & Mayo Fdn, Dept Pharmacol, Rochester, MN 55905 USA. Mayo Clin & Mayo Fdn, Dept Biochem & Mol Biol, Rochester, MN 55905 USA. Mayo Clin & Mayo Fdn, Mol Neurosci Program, Rochester, MN 55905 USA. Univ Nebraska, Med Ctr, Eppley Inst Res Canc & Allied Dis, Omaha, NE 68198 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP McMurray, CT (reprint author), Mayo Clin & Mayo Fdn, Dept Pharmacol, 200 1St St Sw, Rochester, MN 55905 USA. FU NCI NIH HHS [P30 CA36727]; NIDDK NIH HHS [DK 43694-01A2]; NIMH NIH HHS [MH-56207] NR 39 TC 126 Z9 127 U1 0 U2 3 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 DEC PY 1999 VL 4 IS 6 BP 1079 EP 1085 DI 10.1016/S1097-2765(00)80236-1 PG 7 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 269PC UT WOS:000084485900019 PM 10635332 ER PT J AU Mason, TE Taylor, AD AF Mason, TE Taylor, AD TI Neutron scattering in materials research SO MRS BULLETIN LA English DT Editorial Material C1 Spallat Neutron Source, Oak Ridge, TN USA. Rutherford Appleton Lab, ISIS Spallat Neutron Source, Oxford, England. RP Mason, TE (reprint author), Spallat Neutron Source, Oak Ridge, TN USA. RI Mason, Thomas/M-5809-2014 OI Mason, Thomas/0000-0003-1880-3971 NR 6 TC 3 Z9 4 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD DEC PY 1999 VL 24 IS 12 BP 14 EP 14 PG 1 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 266XB UT WOS:000084324600017 ER PT J AU Radaelli, PG Jorgensen, JD AF Radaelli, PG Jorgensen, JD TI Neutron diffraction from novel materials SO MRS BULLETIN LA English DT Article ID POWDER-DIFFRACTION; STRUCTURAL-PROPERTIES; OXIDE SUPERCONDUCTORS; CRYSTAL-STRUCTURE; T-C; C-60; PHASE; LA1.2SR1.8MN2O7; TEMPERATURE; CHARGE C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. RP Radaelli, PG (reprint author), Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. RI Radaelli, Paolo/C-2952-2011 OI Radaelli, Paolo/0000-0002-6717-035X NR 34 TC 0 Z9 0 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD DEC PY 1999 VL 24 IS 12 BP 24 EP 28 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 266XB UT WOS:000084324600019 ER PT J AU Lindner, P Wignall, G AF Lindner, P Wignall, G TI Neutron-scattering measurements of "soft matter" SO MRS BULLETIN LA English DT Article ID SUPERCRITICAL CARBON-DIOXIDE; SMALL-ANGLE NEUTRON; BLENDS C1 Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. ORNL, Div Solid State, Oak Ridge, TN USA. RP Lindner, P (reprint author), Inst Max Von Laue Paul Langevin, BP 156X, F-38042 Grenoble, France. NR 23 TC 7 Z9 7 U1 1 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD DEC PY 1999 VL 24 IS 12 BP 34 EP 39 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 266XB UT WOS:000084324600021 ER PT J AU Craig, TA Benson, LM Tomlinson, AJ Veenstra, TD Naylor, S Kumar, R AF Craig, TA Benson, LM Tomlinson, AJ Veenstra, TD Naylor, S Kumar, R TI Analysis of transcription complexes and effects of ligands by microelectrospray ionization mass spectrometry SO NATURE BIOTECHNOLOGY LA English DT Article DE mass spectrometry; vitamin D receptors; retinoic acid receptors; transcription; DNA response elements ID RETINOID-X RECEPTOR; DNA-BINDING DOMAIN; ELECTROSPRAY-IONIZATION; VITAMIN-D; NUCLEAR RECEPTOR; D-3 RECEPTOR; RESPONSE ELEMENTS; MOLECULAR ACTIONS; ACID RECEPTORS; PROTEIN AB The human vitamin D receptor (VDR) and retinoid X receptor-alpha (RXR alpha) modulate gene activity by forming homodimeric or heterodimeric complexes with specific DNA sequences and interaction with other elements of the transcriptional apparatus in the presence of their known endogenous ligands 1 alpha,25-dihydroxyvitamin D-3 (1,25-[OH](2)D-3) and 9-cis-retinoic acid (9-c-RA). We used rapid buffer exchange gel filtration in conjunction with microelectrospray ionization mass spectrometry (mu ESI-MS) to study the binding of these receptors to the osteopontin vitamin D response element (OP VDRE). In the absence of DNA, both VDR and RXR alpha existed primarily as monomers, but in the presence of OP VDRE, homodimeric RXR alpha and heterodimeric RXR alpha-VDR complexes were shown to bind OP VDRE. Addition of 9-c-RA increased RXR alpha homodimer-OP VDRE complexes, and addition of 1,25-(OH)2D3 resulted in formation of 1,25-(OH)(2)D-3-VDR-RXR alpha-OP VDRE complexes. Addition of low-affinity binding ligands had no detectable effect on the VDR-RXR alpha-OP VDRE transcription complex. These results demonstrate the utility of mu ESI-MS in analyzing multimeric, high-molecular-weight protein-protein and protein-DNA complexes, and the effects of ligands on these transcriptional complexes. C1 Mayo Clin, Nephrol Res Unit, Rochester, MN 55905 USA. Mayo Clin, Biomed Mass Spectrometry Facil, Rochester, MN 55905 USA. Mayo Clin, Dept Biochem & Mol Biol, Rochester, MN 55905 USA. Mayo Clin, Dept Med, Rochester, MN 55905 USA. Mayo Clin, Dept Pharmacol, Rochester, MN 55905 USA. Mayo Clin, Clin Pharmacol Unit, Rochester, MN 55905 USA. Pacific NW Natl Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Naylor, S (reprint author), Mayo Clin, Nephrol Res Unit, Rochester, MN 55905 USA. FU NIDDK NIH HHS [R01 DK025409, DK 25409] NR 42 TC 33 Z9 33 U1 0 U2 5 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1087-0156 J9 NAT BIOTECHNOL JI Nat. Biotechnol. PD DEC PY 1999 VL 17 IS 12 BP 1214 EP 1218 PG 5 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 264FV UT WOS:000084170700031 PM 10585721 ER PT J AU Kim, SH Kaminker, P Campisi, J AF Kim, SH Kaminker, P Campisi, J TI TIN2, a new regulator of telomere length in human cells SO NATURE GENETICS LA English DT Article ID SACCHAROMYCES-CEREVISIAE; REPLICATIVE SENESCENCE; CHROMOSOME STABILITY; RETROVIRAL VECTORS; HUMAN FIBROBLASTS; GENE-TRANSFER; RAP1 PROTEIN; LIFE-SPAN; IN-VITRO; YEAST AB Telomeres are DNA-protein structures that cap linear chromosomes and are essential for maintaining genomic stability and cell phenotype. We identified a novel human telomere-associated protein, TIN2, by interaction cloning using the telomeric DNA-binding-protein TRF1 as a bait. TIN2 interacted with TRF1 in vitro and in cells, and colocalized with TRF1 in nuclei and metaphase chromosomes. A mutant TIN2 that lacks amino-terminal sequences effects elongated human telomeres in a telomerase-dependent manner. Our findings suggest that TRF1 is insufficient for control of telomere length in human cells, and that TIN2 is an essential mediator of TRF1 function. C1 Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Berkeley, CA 94720 USA. RP Campisi, J (reprint author), Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Berkeley, CA 94720 USA. FU NIA NIH HHS [AG00266, AG09909, R37 AG009909, T32 AG000266] NR 47 TC 336 Z9 355 U1 2 U2 13 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1061-4036 J9 NAT GENET JI Nature Genet. PD DEC PY 1999 VL 23 IS 4 BP 405 EP 412 PG 8 WC Genetics & Heredity SC Genetics & Heredity GA 261RZ UT WOS:000084023900014 PM 10581025 ER PT J AU Herrera, VLM Makrides, SC Xie, HX Adari, H Krauss, RM Ryan, US Ruiz-Opazo, N AF Herrera, VLM Makrides, SC Xie, HX Adari, H Krauss, RM Ryan, US Ruiz-Opazo, N TI Spontaneous combined hyperlipidemia, coronary heart disease and decreased survival in Dahl salt-sensitive hypertensive rats transgenic for human cholesteryl ester transfer protein SO NATURE MEDICINE LA English DT Article ID MONOCYTE CHEMOATTRACTANT PROTEIN-1; APOLIPOPROTEIN-A-I; MESSENGER-RNA; AORTIC ATHEROSCLEROSIS; MICE; GENE; SUSCEPTIBILITY; LIPOPROTEINS; TISSUES; PLASMA AB The acceleration of atherosclerosis by polygenic (essential) hypertension is well-characterized in humans; however, the lack of an animal model that simulates human disease hinders the elucidation of pathogenic mechanisms. We report here a transgenic atherosclerosis-polygenic hypertension model in Dahl salt-sensitive hypertensive rats that overexpress the human cholesteryl ester transfer protein (Tg[hCETP](DS)). Male Tg[hCETP](DS) rats fed regular rat chow showed age-dependent severe combined hyperlipidemia, atherosclerotic lesions, myocardial infarctions and decreased survival. These findings differ from various mouse atherosclerosis models, demonstrating the necessity of complex disease modeling in different species. The data demonstrate that cholesteryl ester transfer protein can be proatherogenic. The interaction of polygenic hypertension and hyperlipidemia in the pathogenesis of atherosclerosis in Tg[hCETP](DS) rats substantiates epidemiological observations in humans. C1 Boston Univ, Sch Med, Whitaker Cardiovasc Inst, Boston, MA 02118 USA. Avant Immunotherapies, Needham, MA 02494 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol Med, Berkeley, CA 94720 USA. RP Herrera, VLM (reprint author), Boston Univ, Sch Med, Whitaker Cardiovasc Inst, 700 Albany St, Boston, MA 02118 USA. NR 48 TC 88 Z9 90 U1 2 U2 4 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1078-8956 J9 NAT MED JI Nat. Med. PD DEC PY 1999 VL 5 IS 12 BP 1383 EP 1389 DI 10.1038/70956 PG 7 WC Biochemistry & Molecular Biology; Cell Biology; Medicine, Research & Experimental SC Biochemistry & Molecular Biology; Cell Biology; Research & Experimental Medicine GA 262DE UT WOS:000084049700037 PM 10581080 ER PT J AU Newcomer, BR Boska, MD Hetherington, HP AF Newcomer, BR Boska, MD Hetherington, HP TI Non-P-i buffer capacity and Initial phosphocreatine breakdown and resynthesis kinetics of human gastrocnemius/soleus muscle groups using 0.5 s time-resolved P-31 MRS at 4.1 T SO NMR IN BIOMEDICINE LA English DT Article DE P-31 of exercising muscle; non-P-i buffer capacity ID HUMAN SKELETAL-MUSCLE; MAGNETIC-RESONANCE; PRODUCTION-RATES; EXERCISE; RECOVERY; INVIVO AB High-time-resolution (0.5 s) P-31 MRS has been used to evaluate the initial phosphoreatine (PCr) breakdown and resynthesis kinetics, to calculate the non-P-i/non-bicarbonate buffer capacity (beta(non-P/non-bicarb)), and to calculate the constant relating the change in intracellular pH to the muscle's H+ efflux rate (lambda), The slope of PCr vs time demonstrates that a slope calculated using the first 10 s of recovery underestimates initial PCr recovery rates by up to 56%. A 1-2 s time window is needed to produce a slope that is statistically equivalent to the slope measured using a 0.5 s time window (p = 0.008, one-way RM-ANOVA, Student-Newman-Keuls multiple comparison test). In addition, there was no delay or acceleration in PCr recovery after a 90 s maximum voluntary contraction (MVC) in normal subjects. This demonstrates that. oxidative metabolism is occurring at the end of a 90-s MVC in normal individuals. Fitting recovery data has determined that beta(non-Pi/non-bicarb) = 24.3 +/- 5.4 slyke (mmol/L/pH unit) and that lambda = 0.129 +/- 0.077 mM/(ph s) for human gastrocnemius/soleus muscle. beta(non-Pi/non-bicarb) is in agreement with measurements in cat biceps, cat soleus and rat gastrocnemius muscles. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Alabama, Dept Crit & Diagnost Care, Birmingham, AL 35294 USA. Henry Ford Hosp, NMR Neurol Dept, Detroit, MI 48202 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Newcomer, BR (reprint author), Univ Alabama, Dept Crit & Diagnost Care, Birmingham, AL 35294 USA. FU NCRR NIH HHS [RR07723] NR 19 TC 20 Z9 20 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0952-3480 J9 NMR BIOMED JI NMR Biomed. PD DEC PY 1999 VL 12 IS 8 BP 545 EP 551 DI 10.1002/(SICI)1099-1492(199912)12:8<545::AID-NBM595>3.0.CO;2-J PG 7 WC Biophysics; Radiology, Nuclear Medicine & Medical Imaging; Spectroscopy SC Biophysics; Radiology, Nuclear Medicine & Medical Imaging; Spectroscopy GA 282RM UT WOS:000085232300008 PM 10668047 ER PT J AU Hamilton, MA Rogers, RD Nelson, LO Holmes, RG Milner, TN AF Hamilton, MA Rogers, RD Nelson, LO Holmes, RG Milner, TN TI Biodecontamination: cost-benefit analysis of a novel approach for decontamination of massive concrete structures SO NUCLEAR ENERGY-JOURNAL OF THE BRITISH NUCLEAR ENERGY SOCIETY LA English DT Article ID CORROSION AB A major liability facing the owners and operators of nuclear facilities worldwide is the decontamination and decommissioning (D&D) of contaminated massive concrete structures. A biodecontamination technology which harnesses the action of naturally occurring bacteria is currently under joint development by BNFL and the Idaho National Engineering and Environmental Laboratory. This emerging technology was judged to exhibit advantages in cost, worker health and safety risk reduction, and programmatic effectiveness. The process takes approximately six months to one year to remove the contaminated surface and can advantageously be applied during the care and maintenance phase of a D&D programme. A detailed assessment of the biodecontamination process in relation to the next best and base technologies was performed. The findings of this study, which recommended a large-scale technology demonstration,will be presented. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID USA. RP Hamilton, MA (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU BRITISH NUCLEAR ENERGY SOC PI WESTMINSTER, LONDON PA 1-7 GREAT GEORGE ST, WESTMINSTER, LONDON, ENGLAND SW1P 3AA SN 0140-4067 J9 NUCL ENERG-J BR NUCL JI Nucl. Energy-J. Br. Nucl. Energy Soc. PD DEC PY 1999 VL 38 IS 6 BP 351 EP 355 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 274KT UT WOS:000084765600011 ER PT J AU Park, JJ Buksa, JJ Houts, MG Arthur, ED AF Park, JJ Buksa, JJ Houts, MG Arthur, ED TI Estimates of the service lifetime of 304 stainless steel for use in the blanket region of the LANL ABC system SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article AB The corrosion and fluence limits of stainless steel were evaluated to determine if it could be used as a blanket material in the accelerator-based conversion of plutonium (ABC) system at Los Alamos National Laboratory (LANL). Data from the Molten Salt Breeder Reactor program at Oak Ridge National Laboratory and the redox potential of the ABC system indicated that, from a corrosion perspective, 304L stainless steel might be useful for system components having lifetimes of up to 2 years. To determine the applicability of 304 stainless steel, its service lifetime was estimated from fluence-limit data used in the design of the Fast Flux Test Facility. The fluxes for components of the system were calculated with the Monte Carlo N-Particle (MCNP) code. After fluence limits of the stainless steel components were calculated for various temperatures, the expected lifetimes of the components were established for various fluxes and temperatures, based on 5 and 10% residual ductility criteria. The results showed that expected lifetimes for the components would be less than 1.6 years, and therefore, they do not meet the present goal of replacing the components every 2 years. However, it should be noted that the data obtained in this research are tentative and are likely to change as the LANL ABC system design moves forward. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Park, JJ (reprint author), Univ Calif Los Alamos Natl Lab, MS E508,POB 1663, Los Alamos, NM 87545 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 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 DEC PY 1999 VL 194 IS 2-3 BP 151 EP 159 DI 10.1016/S0029-5493(99)00193-4 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 262CU UT WOS:000084048700003 ER PT J AU Chopra, OK Chung, HM Kassner, TF Park, JH Shack, WJ Zhang, J Brust, FW Dong, P AF Chopra, OK Chung, HM Kassner, TF Park, JH Shack, WJ Zhang, J Brust, FW Dong, P TI Current research on environmentally assisted cracking in light water reactor environments SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 25th Water Reactor Safety Information Meeting CY OCT 20-22, 1997 CL BETHESDA, MD ID PRESSURE-VESSEL STEELS; LOW-ALLOY STEELS; FATIGUE; CARBON; BEHAVIOR; LIFE AB The effect of dissolved oxygen level on fatigue life of austenitic stainless steels is discussed and the results of a detailed study of the effect of the environment on the growth of cracks during fatigue initiation are presented. Initial test results are given for specimens irradiated in the Halden reactor. Impurities introduced by shielded metal are welding that may affect susceptibility to stress corrosion cracking are described. Results of calculations of residual stresses in core shroud weldments are summarized. Crack growth rates of high-nickel alloys under cyclic loading with R ratios from 0.2 to 0.95 in high-purity water that contains <5 and 300 ppb dissolved oxygen at 240, 289, and 320 degrees C, are summarized. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Battelle Mem Inst, Columbus Labs, Columbus, OH 43201 USA. RP Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. EM omesh_chopra@qmgate.anl.gov NR 37 TC 20 Z9 21 U1 2 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 EI 1872-759X J9 NUCL ENG DES JI Nucl. Eng. Des. PD DEC PY 1999 VL 194 IS 2-3 BP 205 EP 223 DI 10.1016/S0029-5493(99)00206-X PG 19 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 262CU UT WOS:000084048700009 ER PT J AU Rubin, AM Chen, JT Sewell, R Lambright, J Kazarians, M Nowlen, SP Bohn, MP Chokshi, N AF Rubin, AM Chen, JT Sewell, R Lambright, J Kazarians, M Nowlen, SP Bohn, MP Chokshi, N TI An update of preliminary perspectives gained from individual plant examination of external events (IPEEE) submittal reviews SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 25th Water Reactor Safety Information Meeting CY OCT 20-22, 1997 CL BETHESDA, MARYLAND AB As a result of the US Nuclear Regulatory Commission (USNRC) initiated Individual Plant Examination of External Events (IPEEE) program, virtually every operating commercial nuclear power reactor in the United States has performed an assessment of severe accident risk due to external events. The USNRC staff has received all 70 IPEEE submittals. This paper is based on the information available for those 41 plants for which at least preliminary Technical Evaluation Reports have been prepared by the review teams. The goal of the review is to ascertain whether the licensee's IPEEE process is capable of identifying external events-induced severe accident vulnerabilities and cost-effective safety improvements to either eliminate or reduce the impact of these vulnerabilities. The review does not, however, attempt to validate or verify the results of the licensee's IPEEE. The primary objective of this paper is to provide an update on the preliminary perspectives and insights gained from the IPEEE process. For most licensees the principal objectives of the IPEEE program have been met, and the program has had some impact on improving plant safety. (C) 1999 Elsevier Science S.A. All rights reserved. C1 US Nucl Regulatory Commiss, Off Nucl Regulatory Res, Washington, DC 20555 USA. Energy Res Inc, Rockville, MD 20852 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Rubin, AM (reprint author), US Nucl Regulatory Commiss, Off Nucl Regulatory Res, Washington, DC 20555 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 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 DEC PY 1999 VL 194 IS 2-3 BP 225 EP 250 DI 10.1016/S0029-5493(99)00207-1 PG 26 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 262CU UT WOS:000084048700010 ER PT J AU Korsah, K Ewing, PD Kercel, S Wood, RT Antonescu, C Tanaka, T AF Korsah, K Ewing, PD Kercel, S Wood, RT Antonescu, C Tanaka, T TI Current research results on the technical basis for environmental qualification of safety-related digital I&C hardware in nuclear power plants SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 25th Water Reactor Safety Information Meeting CY OCT 20-22, 1997 CL BETHESDA, MARYLAND AB This paper presents progress to date of an NRC-sponsored confirmatory research program initiated to address hardware issues associated with the use of safety-related digital instrumentation and control (I&C) hardware in nuclear power plants. In particular, the potential vulnerability of digital technology to environmental stress effects and means for establishing environmental compatibility for digital I&C systems were studied. The research approach involved evaluating existing military and industrial guidance, identifying the most significant environmental stressors and, for advanced I&C systems in nuclear power plants, investigating the likely failure modes-both at the integrated circuit and system level-for digital technologies under varying levels of environmental stress. Environmental stressors used in the studies included smoke exposure, electromagnetic and radio-frequency interference (EMI/RFI), temperature, and humidity. The insights gained from these studies are being used to recommend appropriate methods for qualifying safety-related digital equipment in nuclear power plants. To characterize the EMI/RFI environment at current LWRs and to estimate the expected environment at ALWRs, ORNL conducted a long-term survey of ambient electromagnetic conditions at several nuclear power plants. A representative sampling of power plant conditions (reactor type, operating mode, site location) were monitored over extended observation periods (e.g., continuous measurements for up to 5 weeks at a single location) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. The results of this study contributed to the technical basis for a Nuclear Regulatory Commission Draft Regulatory Guide (DG-1029) issued for comment in 1998. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37831 USA. US Nucl Regulatory Commiss, Rockville, MD 20852 USA. Sandia Natl Labs, Albuquerque, NM 87123 USA. RP Korsah, K (reprint author), Oak Ridge Natl Lab, Div Instrumentat & Controls, POB 2008, Oak Ridge, TN 37831 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 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 DEC PY 1999 VL 194 IS 2-3 BP 251 EP 257 DI 10.1016/S0029-5493(99)00208-3 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 262CU UT WOS:000084048700011 ER PT J AU Tanaka, TJ Nowlen, SP Antonescu, C AF Tanaka, TJ Nowlen, SP Antonescu, C TI Recent results of an experimental study on the impact of smoke on digital I & C equipment SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 25th Water Reactor Safety Information Meeting CY OCT 20-22, 1997 CL BETHESDA, MARYLAND AB A program to assess the impact of smoke on digital instrumentation and control (I & C) safety systems began in 1994, funded by the US Nuclear Regulatory Commission Office of Research. Digital I & C safety systems are likely replacements for today's analog systems. The nuclear industry has little experience in qualifying digital electronics for critical systems, part of which is understanding system performance during plant fires. The results of tests evaluating the performance of digital circuits and chip technologies exposed to the various smoke and humidity conditions representative of cable fires are discussed. Tests results show that low to moderate smoke densities can cause intermittent failures of digital systems. Smoke increases leakage currents between biased contacts, leading to shorts. Chips with faster switching times, and thus higher output drive currents, are less sensitive to leakage currents and thus to smoke. Contact corrosion from acidic gases in smoke and stray inductance or capacitance are less important contributors to system upset. Transmission line coupling was increased because the smoke acted as a conductive layer between the lines. Permanent circuit damage was not obvious in the 24 h of circuit monitoring. Test results also show that polyurethane, parylene, and acrylic conformal coatings are more effective in protecting against smoke than epoxy or silicone. Common sense mitigation measures are discussed. Unfortunately we are a long way from standard tests for smoke exposure that capture the variations in smoke exposure possible in an actual fire. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Accid & Consequence Anal Dept, Albuquerque, NM 87185 USA. US Nucl Regulatory Commiss, Washington, DC 20555 USA. Off Nucl Regulatory Res, Washington, DC 20555 USA. RP Tanaka, TJ (reprint author), Sandia Natl Labs, Accid & Consequence Anal Dept, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 0 Z9 1 U1 0 U2 2 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 DEC PY 1999 VL 194 IS 2-3 BP 259 EP 269 DI 10.1016/S0029-5493(99)00209-5 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 262CU UT WOS:000084048700012 ER PT J AU Tracy, JG AF Tracy, JG TI High-purity enrichment of Sr-84 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE calutron; isotope separation; strontium AB High-purity Sr-84 (i.e., > 99 at %) is an important tool in many areas of basic and applied research, in particular for spikes used in isotopic dilution/mass spectrometer investigations in geochemistry, cosmochemistry, and paleoclimate-age studies. In nature, the Sr-84 abundance is only 0.56%; however, it can be enriched to the specified requirements by using a high-resolution separator, such as the 180 degrees-sector separator, or by completing two passes through a high-production, lower-resolution machine, such as the calutron. The latter option was used for this enrichment to produce similar to Ig of strontium with a final Sr-84 concentration of 99.64%. Three innage runs were made, vaporizing a total of similar to 17 g of metal feed that had been pre-enriched in the calutron to similar to 70% Sr-84. A partial recovery, followed by recycle of the unresolved feed, was made after the second innage run. A process efficiency of 5.44% was achieved, and 4.33 g of the unresolved feed material was recovered. A modified ion-source unit using materials compatible with strontium and the use of krypton as mass markers to aid in operations are described. Standard contamination analyses were performed to evaluate the enrichment and to compare measured results with predicted product purity. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, Oak Ridge, TN 37831 USA. RP Tracy, JG (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, POB 2009,Bldg 9204-3, Oak Ridge, TN 37831 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 1 PY 1999 VL 438 IS 1 BP 1 EP 6 DI 10.1016/S0168-9002(99)00638-5 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300002 ER PT J AU Brashear, DR Zevenbergen, LA AF Brashear, DR Zevenbergen, LA TI Preparation of enriched rare-earth metals by hydrofluorination and reduction SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE erbium; fluoride; induction heating; rare earth; reduction of oxide AB Enriched rare-earth metals are employed in many areas of basic and applied research. Capabilities for preparing enriched rare-earth metals at Oak Ridge National Laboratory have been limited in recent years to reduction-distillation of the oxides of Sm. Eu, and Yb, using La as a reductant. The capability for producing enriched Ce, Nd, Gd, Dy, Er, and Lu in gram quantities has recently been restored via hydrofluorination of the oxide followed by metallothermic reduction employing Ca as a reductant. Typical yields for gram-quantity conversion of rare-earth oxides have been demonstrated to be 90% or greater. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, Oak Ridge, TN 37831 USA. RP Brashear, DR (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, POB 2009,Bldg 9204-3, Oak Ridge, TN 37831 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 1 PY 1999 VL 438 IS 1 BP 23 EP 29 DI 10.1016/S0168-9002(99)00643-9 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300007 ER PT J AU Marcus, C Zevenbergen, LA AF Marcus, C Zevenbergen, LA TI The reduction and distillation of isotopically enriched zinc oxides under high vacuum conditions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE induction heating; reduction of oxide; vacuum deposition; zinc AB Historically, enriched zinc (Zn) metal was produced at the Oak Ridge National Laboratory's Isotope Enrichment Facility (IEF) by either electrodeposition, followed by melting to produce a metal ingot, or purified by hydrogen reduction and distillation at atmospheric pressure in a tube furnace as a prelude to electroplating. Electroplated material was generally poor in quality, and losses were high during subsequent melting. Adapting the distillation purifying technique as an ultimate means of recovery of Zn metal proved to be difficult and inefficient. To resolve these problems, the well-established vacuum reduction/distillation process was adapted for the conversion of Zn oxide to metal. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, Oak Ridge, TN 37831 USA. RP Marcus, C (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Isotope Enrichment Program, POB 2009,Bldg 9204-3, Oak Ridge, TN 37831 USA. NR 5 TC 9 Z9 11 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 DEC 1 PY 1999 VL 438 IS 1 BP 30 EP 35 DI 10.1016/S0168-9002(99)00644-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300008 ER PT J AU Greene, JP Thomas, GE Garcia, A Komives, A Stoner, JO AF Greene, JP Thomas, GE Garcia, A Komives, A Stoner, JO TI Preparation of a 1 mg/cm(2) C-13 target SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE C-13; electron beam heating; multi-layer target; thick target AB We give a description for the production of C-13 foils and the preparation of an approximately 1-mg/cm(2) thick target. A recent experiment to measure the mass of Ca-36, via the Ca-40(He-4,He-8)Ca-36 reaction, required precise determination of the accelerated beam energy and calibration of the focal plane of a magnetic spectrometer to achieve the most accurate value for the Ca-36 mass. A 1 mg/cm(2) C-13 target was essential for these purposes. Target preparation and performance along with some preliminary results will be discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Notre Dame, South Bend, IN 46556 USA. ACF Met, Tucson, AZ 85719 USA. RP Greene, JP (reprint author), Argonne Natl Lab, Div Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Garcia, Alejandro/0000-0001-6056-6645 NR 11 TC 3 Z9 3 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 DEC 1 PY 1999 VL 438 IS 1 BP 52 EP 57 DI 10.1016/S0168-9002(99)00651-8 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300012 ER PT J AU Greene, JP Janssens, RVF Ahmad, I AF Greene, JP Janssens, RVF Ahmad, I TI Preparation of actinide targets by molecular plating for coulomb excitation studies at ATLAS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE actinide; plutonium; curium; electrodeposition; characterization of target ID ELECTRODEPOSITION AB Molecular plating is now routinely used to prepare sources and targets of actinide elements. Although the technique is simple and fairly reproducible, because of the radioactive nature of the targets, it is very useful to record various parameters in the preparation process. At Argonne, similar to 200 mu g/cm(2) thick targets of Pu and Cm were required for Coulomb Excitation (COULEX) studies with the Argonne-Notre Dame boron germanate (BGO) gamma-ray facility and later with the GAMMASPHERE. These targets were plated on 50 mg/cm(2) Au backings and were covered with 150 mu g/cm(2) Au foil. Targets of Pu-239. Pu-240, Pu-242, Pu-244 and Cm-248 were prepared by dissolving the material in isopropyl alcohol and electroplating the actinide ions by applying 600 V. The amount of these materials on the target was determined by alpha particle counting and gamma-ray counting. Details of the molecular plating and counting will be discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Greene, JP (reprint author), Argonne Natl Lab, Div Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 7 TC 11 Z9 12 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 1 PY 1999 VL 438 IS 1 BP 119 EP 123 DI 10.1016/S0168-9002(99)00668-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300023 ER PT J AU O'Neil, JP VanBrocklin, HF AF O'Neil, JP VanBrocklin, HF TI Preparation of fluorine-18 gas from an 11 MeV cyclotron: a target system for the CTI RDS 111 cyclotron SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TN SP Int Nucl Target Dev Soc DE gas target; fluorine-18 AB A fully operational (18)F-fluorine gas production system for the CTI model RDS 111 cyclotron turret target system is presented. The system design and merger with the existing CTI model RDS 112-style fluorine system and experiments toward the optimization of production parameters will be included. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Ctr Funct Imaging, Biomed Isotope Facil, Berkeley, CA 94720 USA. RP O'Neil, JP (reprint author), Lawrence Berkeley Natl Lab, Ctr Funct Imaging, Biomed Isotope Facil, 1 Cyclotron Rd MS 55-121, Berkeley, CA 94720 USA. EM jponeil@lbl.gov NR 8 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 DEC 1 PY 1999 VL 438 IS 1 BP 166 EP 172 DI 10.1016/S0168-9002(99)00671-3 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300028 ER PT J AU Alton, GD Beene, JR Liu, Y AF Alton, GD Beene, JR Liu, Y TI Criteria for selection of target materials and design of high-efficiency-release targets for radioactive ion beam generation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE actinide; carbon - C; characterization of target; cooling of target; CVD; electrodeposition; electrophoresis; fiber target; foam target; heating of target; heavy-ion target; ion implantation; ion source; isotope separation; liquid target; multi-layer target; pellet target; protective layer; radioactive beam; radioactive target; target list; vacuum deposition; very thin target ID FACILITY; IMPLANTATION AB In this report, we define criteria for choosing target materials and for designing, mechanically stable, short-diffusion-length, highly permeable targets for generation of high-intensity radioactive ion beams (RIBs) for use at nuclear physics and astrophysics research facilities based on the ISOL principle. In addition, lists of refractory target materials are provided and examples are given of a number of successful targets, based on these criteria, that have been fabricated and tested for use at the Holifield Radioactive Ion Beam Facility(HRIBF). (C) 1999 Elsevier Science B.V. AII rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Alton, GD (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. NR 22 TC 29 Z9 29 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 DEC 1 PY 1999 VL 438 IS 1 BP 190 EP 209 DI 10.1016/S0168-9002(99)00949-3 PG 20 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300032 ER PT J AU Liu, Y Alton, GD AF Liu, Y Alton, GD TI High-efficiency-release targets for use at ISOL facilities: computational design SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 19th World Conference of the International-Nuclear-Target-Development-Society CY OCT 05-09, 1998 CL OAK RIDGE, TENNESSEE SP Int Nucl Target Dev Soc DE carbon-C; characterization of target; fiber target; fluorine-F; heating of target; radioactive beam ID ION-BEAM FACILITY AB This report describes efforts made at the Oak Ridge National Laboratory to design high-efficiency-release targets that simultaneously incorporate the short diffusion lengths, high permeabilities, controllable temperatures, and heat-removal properties required for the generation of useful radioactive ion beam (RIB) intensities for nuclear physics and astrophysics research using the isotope separation on-line (ISOL) technique. Short diffusion lengths are achieved either by using thin fibrous target materials or by coating thin layers of selected target material onto low-density carbon fibers such as reticulated-vitreous-carbon fiber (RVCF) or carbon-bonded-carbon fiber (CBCF) to form highly permeable composite target matrices. Computational studies that simulate the generation and removal of primary beam deposited heat from target materials have been conducted to optimize the design of target/heat-sink systems for generating RIBs. The results derived from diffusion release-rate simulation studies for selected targets and thermal analyses of temperature distributions within a prototype target/heat-sink system subjected to primary ion beam irradiation are presented in this report. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Liu, Y (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 1 PY 1999 VL 438 IS 1 BP 210 EP 216 DI 10.1016/S0168-9002(99)00950-X PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261QP UT WOS:000084020300033 ER PT J AU Charlton, WS Stanbro, WD Perry, RT Fearey, BL AF Charlton, WS Stanbro, WD Perry, RT Fearey, BL TI Comparisons of calculated and measured Np-237, Am-241, and Am-243 concentrations as a function of the Pu-240/Pu-239 isotopic ratio in spent fuel SO NUCLEAR TECHNOLOGY LA English DT Article DE international safeguards; actinide calculations; burnup calculations ID CODE AB The Los Alamos National Laboratory (LANL) has developed a system for determining Np-237, Am-241, and (243)A, concentrations in spent fuel from measurements of the Pu-240/Pu-239 isotopic ratio using calculations performed with the HELIOS lattice-physics code. Benchmark calculations for several pressurized water reactors (PWRs) were performed and compared to measured values from the literature for fuels with burnups ranging from 0 to 50 000 MWd/tonne U. A direct correlation can be found between the Pu-240/Pu-239 isotopic ratio and the higher-actinide concentrations for each fuel type. Comparisons of calculated with measured values suggests that the LANL technique would yield Np-237 and Am-241 concentrations within +/-5% and Am-243 concentrations within +/-15% for PWRs. Expanding this system for all reprocessing applications will require more measured data (especially for boiling water reactors and WEE-type reactors), but the existing results show a marked improvement over the previous ORIGEN calculations. Also, a better determination of the Am-243 concentrations may support a greater confidence in the calculated results or suggest an alteration to the existing nuclear data. The present state of these neutronics calculations suggests that the technology exists to reduce the need for direct measurement of the Np-237, Am-241, and (243)AM concentrations in spent fuel. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Charlton, WS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 15 TC 7 Z9 7 U1 1 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 DEC PY 1999 VL 128 IS 3 BP 285 EP 299 PG 15 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 256CR UT WOS:000083708800001 ER PT J AU Kim, YS Olander, DR Yagnik, SK AF Kim, YS Olander, DR Yagnik, SK TI Liquid-metal-bonded gap for light water reactor fuel rods SO NUCLEAR TECHNOLOGY LA English DT Article DE light water reactor; fuel rods; liquid-metal gap; compatibility tests AB As a means of improving the gap-thermal conductance, a liquid metal (LM) is proposed as the gap-filling material replacing helium gas in the conventional light water reactor fuel rod. The potential application of the concept includes power reactor fuel rods, special-purpose test-reactor experimental rods, and mixed-oxide fuel rods. Novel fabrication methods to ensure a uniform LIM-filled gap between the fuel and the cladding of minirods have been developed. The main concern was overcoming the large surface tension of an LM to eliminate LM-free spats in the gap. Compatibility tests of the LM with a Zircaloy tube have been conducted. Liquid gallium showed excessive reaction with Zircaloy at 350 degrees C for a month. Liquid Bi-Sn-Pb alloy, on the other hand, showed a nearly negligible reaction with Zircaloy under the same conditions. Thermal superiority of the LM-bonded gap over a conventional helium-gas gap in a miniature fuel rod was confirmed through theoretical calculations and experimental measurements. The experiments involved water-quenching the element from 600 degrees C and measuring the decrease of the fuel centerline temperature. The LM-bonded element reached 100 degrees C in 10 s, while the gas-bonded element required nearly 100 s to attain this temperature. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Elect Power Res Inst, Palo Alto, CA 94304 USA. RP Kim, YS (reprint author), Argonne Natl Lab, Idaho Falls, ID 83403 USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD DEC PY 1999 VL 128 IS 3 BP 300 EP 312 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 256CR UT WOS:000083708800002 ER PT J AU Shapira, Y AF Shapira, Y TI Model case analysis of an algebraic multilevel method SO NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS LA English DT Article DE algebraic multilevel method; coarsening procedure; diffusion problem; discontinuous coefficients ID FINITE-ELEMENT SPACES; ELLIPTIC PROBLEMS; MULTIGRID ALGORITHMS; INDEFINITE PROBLEMS; LINEAR-SYSTEMS; PRECONDITIONERS; CONVERGENCE; COEFFICIENTS; SOLVER AB A multilevel method for the solution of sparse linear systems is introduced. The method is defined in terms of the coefficient matrix alone; no underlying PDE or mesh is assumed. An upper bound for the condition number is available for a class of SPD problems. In particular, for certain discretizations of diffusion boundary value problems, this bound grows only polynomially with the number of levels used, regardless of whether or not the discontinuities in the diffusion coefficient align with the coarse grids. Numerical results in line with the analysis are presented. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Shapira, Y (reprint author), Technion Israel Inst Technol, Dept Comp Sci, IL-32000 Haifa, Israel. NR 43 TC 4 Z9 4 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1070-5325 J9 NUMER LINEAR ALGEBR JI Numer. Linear Algebr. Appl. PD DEC PY 1999 VL 6 IS 8 BP 655 EP 685 DI 10.1002/(SICI)1099-1506(199912)6:8<655::AID-NLA168>3.0.CO;2-P PG 31 WC Mathematics, Applied; Mathematics SC Mathematics GA 273YF UT WOS:000084736400002 ER PT J AU Maino, G Mashnik, SG Prozorkevich, AV Smolyansky, SA AF Maino, G Mashnik, SG Prozorkevich, AV Smolyansky, SA TI Dynamical symmetries in nuclear muon capture SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS LA English DT Article ID BETA-DECAY; MODEL AB Muon capture on N not equal Z nuclei is discussed within an algebraic approach in the frame of the version 3 of the interacting boson model (IBM) of nuclear structure, thus including the isospin degree of freedom. A simple formula for the capture rate is worked out and compared with experimental data. Inclusive measurements are suggested in order to verify the validity of an IBM-4 supersymmetry scheme for the sd-shell nuclei. C1 ENEA, Div Appl Phys, I-40129 Bologna, Italy. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Saratov NG Chernyshevskii State Univ, Dept Phys, Saratov 410071, Russia. RP ENEA, Div Appl Phys, Via Don G Fiammelli 2, I-40129 Bologna, Italy. EM maino@bologna.enea.it RI Maino, Giuseppe/D-4628-2015 OI Maino, Giuseppe/0000-0002-6514-908X NR 39 TC 0 Z9 0 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 1124-1861 J9 NUOVO CIMENTO A JI Nuovo Cimento Soc. Ital. Fis. A-Nucl. Part. Fields PD DEC PY 1999 VL 112 IS 12 BP 1489 EP 1499 PG 11 WC Physics, Particles & Fields SC Physics GA 303CT UT WOS:000086403800009 ER PT J AU Adams, JJ Bibeau, C Page, RH Krol, DM Furu, LH Payne, SA AF Adams, JJ Bibeau, C Page, RH Krol, DM Furu, LH Payne, SA TI 4.0-4.5-mu m lasing of Fe : ZnSe below 180 K, a new mid-infrared laser material SO OPTICS LETTERS LA English DT Article ID ZINC CHALCOGENIDES AB Lasing of Fe:ZnSe is demonstrated, for the first time to the authors' knowledge, for temperatures ranging from 15 to 180 K. The output wavelength of the Fe:ZnSe laser was observed to tune with temperature from 3.98 mu m at 15 K to 4.54 mu m at 180 K. With an Er:YAG laser operating at 2.698 mu m as the pump source, a maximum energy per pulse of 12 mu J at 130 K was produced. Laser slope efficiencies of 3.2% at 19 K and 8.2% at 150 K were determined for an output coupling of 0.6%. A laser emission linewidth of 0.007 mu m at 3.98 mu m was measured at 15 K Absorption and emission spectra and emission lifetimes for Fe:ZnSe are also discussed. (C) 1999 Optical Society of America. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Adams, JJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 12 TC 116 Z9 119 U1 1 U2 14 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 DEC 1 PY 1999 VL 24 IS 23 BP 1720 EP 1722 DI 10.1364/OL.24.001720 PG 3 WC Optics SC Optics GA 260PW UT WOS:000083959900022 PM 18079914 ER PT J AU Kelly, D Grace, KM Song, X Swanson, BI Frayer, D Mendes, SB Peyghambarian, N AF Kelly, D Grace, KM Song, X Swanson, BI Frayer, D Mendes, SB Peyghambarian, N TI Integrated optical biosensor for detection of multivalent proteins SO OPTICS LETTERS LA English DT Article AB We have developed a simple, highly sensitive and specific optical waveguide sensor for the detection of multivalent proteins. The optical biosensor is based on optically tagged glycolipid receptors embedded within a fluid phospholipid bilayer membrane formed upon the surface of a planar optical waveguide. Binding of multivalent cholera toxin triggers a fluorescence resonance energy transfer that results in;a two-color optical change that is monitored by measurement of emitted luminescence above the waveguide surface. The sensor approach is highly sensitive and specific and requires no additional reagents and washing steps. Demonstration of protein-receptor recognition by use of planar optical waveguides provides a path forward for the development of fieldable miniaturized biosensor arrays. (C) 1999 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. RP Kelly, D (reprint author), Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, POB 1663, Los Alamos, NM 87545 USA. RI Mendes, Sergio/A-4708-2008 OI Mendes, Sergio/0000-0002-9462-9058 NR 13 TC 17 Z9 19 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD DEC 1 PY 1999 VL 24 IS 23 BP 1723 EP 1725 DI 10.1364/OL.24.001723 PG 3 WC Optics SC Optics GA 260PW UT WOS:000083959900023 PM 18079915 ER PT J AU Nicholson, JW Jasapara, J Rudolph, W Omenetto, FG Taylor, AJ AF Nicholson, JW Jasapara, J Rudolph, W Omenetto, FG Taylor, AJ TI Full-field characterization of femtosecond pulses by spectrum and cross-correlation measurements SO OPTICS LETTERS LA English DT Article ID LASER-PULSES; ULTRASHORT; PHASE AB We present a practical and accurate technique for retrieving the amplitude and the phase of ultrashort pulses from a nonlinear (second-order) intensity cross correlation and the spectrum that overcomes shortcomings of previous attempts. We apply the algorithm to theoretical and experimental data and compare it with frequency-resolved optical gating. (C) 1999 Optical Society of America. C1 Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nicholson, JW (reprint author), Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. NR 15 TC 92 Z9 92 U1 3 U2 16 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 DEC 1 PY 1999 VL 24 IS 23 BP 1774 EP 1776 DI 10.1364/OL.24.001774 PG 3 WC Optics SC Optics GA 260PW UT WOS:000083959900040 PM 18079930 ER PT J AU Omenetto, FG Nicholson, JW Taylor, AJ AF Omenetto, FG Nicholson, JW Taylor, AJ TI Second-harmonic generation-frequency-resolved optical gating analysis of low-intensity shaped femtosecond pulses at 1.55 mu m SO OPTICS LETTERS LA English DT Article ID CHEMICAL-REACTIONS; LASER-PULSES; PHASE; COMPRESSION AB We illustrate observation and characterization of medium- and low-intensity shaped ultrashort pulses at lambda = 1.55 mu m through single-shot geometry (multishot-average) second-harmonic generation-frequency-resolved optical gating. The pulses are shaped by amplitude filters in the Fourier plane of a compact folded shaper. Sensitivity to pulses with energies of less than 20 pJ and high dynamic range is reported for this configuration. Application of this method to the propagation of similar to 170-fs pulses through a 50-m fiber link is also illustrated. (C) 1999 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Omenetto, FG (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MSK764, Los Alamos, NM 87545 USA. NR 15 TC 16 Z9 16 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD DEC 1 PY 1999 VL 24 IS 23 BP 1780 EP 1782 DI 10.1364/OL.24.001780 PG 3 WC Optics SC Optics GA 260PW UT WOS:000083959900042 PM 18079932 ER PT J AU Leyens, C AF Leyens, C TI Environmental effects on orthorhombic alloy Ti-22Al-25Nb in air between 650 and 1000 degrees C SO OXIDATION OF METALS LA English DT Article DE orthorhombic titanium-aluminide alloy; oxide scale; embrittlement; nitride layer; moisture ID OXIDATION BEHAVIOR; NITROGEN; OXYGEN; RESISTANCE AB The environmental behavior of an orthorhombic titanium-aluminide alloy, Ti-22Al-25Nb, was studied in dry and humid air between 650 and 1000 degrees C by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Microhardness measurements were performed after exposure to gage hardening due to nitrogen and oxygen ingress. The parabolic rate constant of Ti-22Al-25Nb was of the same order as conventional titanium alloys and Ti3Al-base titanium aluminides at and below 750 degrees C. Between 800 and 1000 degrees C, the oxidation resistance of Ti-22Al-25Nb was as good as gamma-TiAl base aluminides; however, the growth rate changed from parabolic to linear after several tens of hours at 900 and 1000 degrees C. The mixed oxide scale consisted of TiO2, AlNbO4, and Al2O3 with TiO2 being the dominant oxide phase. Underneath the oxide scale, a nitride layer formed in the temperature range investigated and, at 1000 degrees C, internal oxidation was observed below this layer. In all cases, oxygen diffused deeply into the subsurface zone and caused severe embrittlement. Microhardness measurements revealed that Ti-22Al-25Nb was hardened in a zone as far as 300 mu m below the oxide scale exposed to air at 900 degrees C for 500 hr. The peak hardness depended on exposure time and reached five times the average hardness of the bulk material under the above conditions. C1 DLR, German Aerosp Ctr, Mat Res Inst, D-51170 Cologne, Germany. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Leyens, C (reprint author), DLR, German Aerosp Ctr, Mat Res Inst, D-51170 Cologne, Germany. NR 34 TC 22 Z9 24 U1 6 U2 12 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 DEC PY 1999 VL 52 IS 5-6 BP 475 EP 503 DI 10.1023/A:1018816300624 PG 29 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 227CH UT WOS:000082060400007 ER PT J AU Jacobson, NS Brady, MP Mehrotra, GM AF Jacobson, NS Brady, MP Mehrotra, GM TI Thermodynamics of selected Ti-Al and Ti-Al-Cr alloys SO OXIDATION OF METALS LA English DT Article DE Ti-Al; Ti-Al-Cr; thermodynamics; Knudsen-cell; mass spectrometry ID ALUMINA SCALE FORMATION; OXIDATION BEHAVIOR; MASS-SPECTROMETRY; SYSTEM; PHASE; STABILITY AB Two alloys in the Ti-Al system (Ti-45 a/o Al, Ti-62Al) and three alloys in the Ti-Al-Cr system (Ti-47Al-2Cr, Ti-47Al-13Cr, Ti-51Al-12Cr) were selected for a thermodynamic study because of interest in their high-temperature oxidation behavior. Activities of Al and Ti were measured using a twin Knudsen-cell assembly with one cell acting as an internal standard. For the Ti-45Al alloy. Al activity was also measured with an EMF technique. The Ti-Al-Cr data were consistent with the Al and Ti activities expected from the adjacent binary Ti-Al phase fields, Implications of this work on oxidation properties are discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Wright State Univ, Dayton, OH 45435 USA. RP NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RI Brady, Michael/A-8122-2008; Jacobson, Nathan/A-9411-2009 OI Brady, Michael/0000-0003-1338-4747; NR 47 TC 34 Z9 35 U1 6 U2 11 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 DEC PY 1999 VL 52 IS 5-6 BP 537 EP 556 DI 10.1023/A:1018820401533 PG 20 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 227CH UT WOS:000082060400009 ER PT J AU Falkenstein, Z AF Falkenstein, Z TI Ozone formation with (V)UV-enhanced dielectric barrier discharges in dry and humid gas mixtures of O-2, N-2/O-2, and Ar/O-2 SO OZONE-SCIENCE & ENGINEERING LA English DT Article DE ozone; (V)UV dielectric barrier discharge; singlet oxygen; photochemical decomposition; excimer; Joshi effect; humid gas mixtures; hydroxyl radical formation; oxygen; nitrogen; argon ID ULTRAVIOLET ILLUMINATION; ATMOSPHERIC CHEMISTRY; PHOTOCHEMICAL DATA; ORGANIC-COMPOUNDS; LIGHT-SOURCE; GENERATION; MECHANISMS; OXIDATION; KINETICS; PLASMAS AB The effect of (V)UV illumination at 172 nm and 253.7 nm on ozone formation with dielectric barrier discharges in air-like mixtures of nitrogen/oxygen and argon/oxygen as function of the water concentration is presented. Although (V)UV at these wavelengths efficiently cleaves ozone, the ozone concentration in a combined (V)UV/dielectric barrier discharge in oxygen-containing gases is reduced only very little. This corresponds to an enhanced concentration of atomic singlet oxygen, which, in presence of water, increases the production of hydroxyl radicals. This is confirmed by measurements of the removal rates of 2-propanol and of its byproducts in dry and humid air in a combined (V)UV/dielectric barrier discharge treatment. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Falkenstein, Z (reprint author), GE, Corp Res & Dev, Lighting Syst Grp, Niskayuna, NY 12309 USA. NR 44 TC 8 Z9 8 U1 0 U2 4 PU CRC PRESS INC PI BOCA RATON PA 2000 CORPORATE BLVD NW, JOURNALS CUSTOMER SERVICE, BOCA RATON, FL 33431 USA SN 0191-9512 J9 OZONE-SCI ENG JI Ozone-Sci. Eng. PD DEC PY 1999 VL 21 IS 6 BP 583 EP 603 DI 10.1080/01919512.1999.10382895 PG 21 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 273TG UT WOS:000084723100004 ER PT J AU Strohmaier, E Dongarra, JJ Meuer, HW Simon, HD AF Strohmaier, E Dongarra, JJ Meuer, HW Simon, HD TI The marketplace of high-performance computing SO PARALLEL COMPUTING LA English DT Article DE high-performance computing; HPC market; supercomputer market; HPC technology; supercomputer technology AB In this paper we analyze the major trends and changes in the High-Performance Computing (HPC) market place since the beginning of the journal 'Parallel Computing'. The initial success of vector computers in the 1970s was driven by raw performance. The introduction of this type of computer systems started the area of 'Supercomputing'. In the 1980s the availability of standard development environments and of application software packages became more important. Next to performance these factors determined the success of MP vector systems, especially at industrial customers. MPPs became successful in the early 1990s due to their better price/performance ratios, which was made possible by the attack of the 'killer-micros'. In the lower and medium market segments the MPPs were replaced by microprocessor based symmetrical multiprocessor (SMP) systems in the middle of the 1990s. There success formed the basis for the use of new cluster concepts for very high-end systems. In the last few years only the companies which have entered the emerging markets for massive parallel database servers and financial applications attract enough business volume to be able to support the hardware development for the numerical high-end computing market as well. Success in the traditional floating point intensive engineering applications seems to be no longer sufficient for survival in the market. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Math Sci Sect, Oak Ridge, TN 37831 USA. Univ Mannheim, Ctr Comp, D-68131 Mannheim, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Strohmaier, E (reprint author), Univ Tennessee, Dept Comp Sci, 107 Ayres Hall, Knoxville, TN 37996 USA. RI Dongarra, Jack/E-3987-2014 NR 8 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 J9 PARALLEL COMPUT JI Parallel Comput. PD DEC PY 1999 VL 25 IS 13-14 BP 1517 EP 1544 DI 10.1016/S0167-8191(99)00067-8 PG 28 WC Computer Science, Theory & Methods SC Computer Science GA 266BY UT WOS:000084281800002 ER PT J AU Sunderam, VS Geist, GA AF Sunderam, VS Geist, GA TI Heterogeneous parallel and distributed computing SO PARALLEL COMPUTING LA English DT Article DE heterogeneous computing; networked computing; cluster computing; message passing interface (MPI); parallel virtual machine (PVM); NAS parallel benchmark; parallel I/O; meta computing AB Heterogeneous network-based distributed and parallel computing is gaining increasing acceptance as an alternative or complementary paradigm to multiprocessor-based parallel processing as well as to conventional supercomputing. While algorithmic and programming aspects of heterogeneous concurrent computing are similar to their parallel processing counterparts, system issues, partitioning and scheduling, and performance aspects are significantly different. In this paper, we discuss the evolution of heterogeneous concurrent computing, in the context of the parallel virtual machine (PVM) system, a widely adopted software system for network computing. In particular, we highlight the system level infrastructures that are required, aspects of parallel algorithm development that most affect performance, system capabilities and limitations, and tools and methodologies for effective computing in heterogeneous networked environments. We also present recent developments and experiences in the PVM project, and comment on ongoing and future work. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Emory Univ, Dept Math & Comp Sci, Atlanta, GA 30322 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Sunderam, VS (reprint author), Emory Univ, Dept Math & Comp Sci, Atlanta, GA 30322 USA. EM vss@mathcs.emory.edu NR 27 TC 13 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 EI 1872-7336 J9 PARALLEL COMPUT JI Parallel Comput. PD DEC PY 1999 VL 25 IS 13-14 BP 1699 EP 1721 DI 10.1016/S0167-8191(99)00088-5 PG 23 WC Computer Science, Theory & Methods SC Computer Science GA 266BY UT WOS:000084281800010 ER PT J AU Womble, DE Dosanjh, SS Hendrickson, B Heroux, MA Plimpton, SJ Tomkins, JL Greenberg, DS AF Womble, DE Dosanjh, SS Hendrickson, B Heroux, MA Plimpton, SJ Tomkins, JL Greenberg, DS TI Massively parallel computing: A Sandia perspective SO PARALLEL COMPUTING LA English DT Article DE massive parallel processing systems; hardware; system software; algorithms; applications; Sandia National Laboratories AB The computing power available to scientists and engineers has increased dramatically in the past decade, due in part to progress in making massively parallel computing practical and available. The expectation for these machines has been great. The reality is that progress has been slower than expected. Nevertheless, massively parallel computing is beginning to realize its potential for enabling significant breakthroughs in science and engineering. This paper provides a perspective on the state of the field, colored by the authors' experiences using large-scale parallel machines at Sandia National Laboratories. We address trends in hardware! system software and algorithms, and we also offer our view of the forces shaping the parallel computing industry. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. CCS, IDA, Bowie, MD 20715 USA. RP Womble, DE (reprint author), Sandia Natl Labs, POB 5800,Mail Stop 1110, Albuquerque, NM 87185 USA. OI Heroux, Michael/0000-0002-5893-0273 NR 16 TC 6 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 J9 PARALLEL COMPUT JI Parallel Comput. PD DEC PY 1999 VL 25 IS 13-14 BP 1853 EP 1876 DI 10.1016/S0167-8191(99)00068-X PG 24 WC Computer Science, Theory & Methods SC Computer Science GA 266BY UT WOS:000084281800015 ER PT J AU Johnson, MT Michael, JR Gilliss, SR Carter, CB AF Johnson, MT Michael, JR Gilliss, SR Carter, CB TI Iron oxide on (001) MgO SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; ALPHA-FE2O3 THIN-FILMS; SURFACE-STRUCTURE; EPITAXIAL-FILMS; LASER-ABLATION; GROWTH; SUBSTRATE; PT(111); ORIENTATION; DIFFRACTION AB Transmission and scanning electron microscopy have been used to characterize thin films of Fe oxide grown on (001)-oriented MgO using pulsed-laser deposition. Several films, each with a longer deposition time, and hence increasing thickness, were grown under similar conditions of oxygen pressure, deposition rate and substrate temperature. For shorter deposition times, i.e. thinner films, a spinel-structured Fe oxide film occurred, while for longer deposition times a corundum-structured Fe oxide film formed. In some instances it was found that the film had a mixture of the two structures of Fe oxide. The analysis of these films determined that the corundum-structured Fe oxide was being formed via a transformation from the spinel structure. This transformation process led to interesting thin-film morphologies and epitactic alignments. C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Johnson, MT (reprint author), Univ Minnesota, Dept Chem Engn & Mat Sci, 421 Washington Ave SE, Minneapolis, MN 55455 USA. RI Carter, C. Barry/E-6478-2010 OI Carter, C. Barry/0000-0003-4251-9102 NR 39 TC 10 Z9 10 U1 0 U2 7 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 DEC PY 1999 VL 79 IS 12 BP 2887 EP 2898 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 266BJ UT WOS:000084280500002 ER PT J AU Kim, KH Chang, CH Koo, YM MacDowell, AA AF Kim, KH Chang, CH Koo, YM MacDowell, AA TI Shape effect related to crystallographic orientation of deformation behaviour in copper single crystals SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article AB The deformation behaviour of pure copper single crystals has been investigated by scanning electron microscopy and synchrotron radiation using the in situ reflection Laue method. Two types of sample with the same orientation of tensile axes, but with different crystallographic orientations in the directions of the width and thickness of the samples, have been studied. They showed different characteristics of deformation behaviour, such as the activated slip systems, the movement of the tensile axis, and the mode of fracture. C1 Pohang Univ Sci & Technol, Ctr Adv Aerosp Mat, Pohang 790784, South Korea. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Kim, KH (reprint author), Pohang Univ Sci & Technol, Ctr Adv Aerosp Mat, Pohang 790784, South Korea. NR 9 TC 1 Z9 1 U1 0 U2 0 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 DEC PY 1999 VL 79 IS 12 BP 919 EP 924 DI 10.1080/095008399176517 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 260LN UT WOS:000083952300004 ER PT J AU Ji, HF Dabestani, R Hettich, RL Brown, GM AF Ji, HF Dabestani, R Hettich, RL Brown, GM TI Optical sensing of cesium using 1,3-alternate calix[4]-mono- and di(anthrylmethyl)aza-crown-6 SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SOLVENT-EXTRACTION; CROWN ETHERS; RECOGNITION; BINDING; IONS; CONFORMATION; FLUORESCENCE; TRANSPORT; MEMBRANE; CATIONS AB We have synthesized two derivatives of alkylanthracene covalently bonded to 1,3-alternate calix[4]aza-crown-6 at the nitrogen position to study the effect of alkali metal ion complexation on the emission properties of anthracene fluorophore. The mono- and dianthryl-substituted probes are weakly fluorescent because their emission is partially quenched by photoinduced electron transfer (PET) from the nitrogen lone pair to the excited singlet state of anthracene. Upon complexation of alkali metal ions (e.g. K+, Cs+) by the crown moiety, the nitrogen lone pair can no longer participate in the PET process causing an enhancement in the emission of anthracene fluorophore (fluorescent turn on). The maximum fluorescence enhancement observed upon complexation of cesium ions by mono- and dianthryl-substituted calix[4]aza-crown-6 relative to the uncomplexed form was 8.5- and 11.6-fold, respectively. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Dabestani, R (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008,MS-6100, Oak Ridge, TN 37831 USA. EM dabestanir@ornl.gov RI Hettich, Robert/N-1458-2016 OI Hettich, Robert/0000-0001-7708-786X NR 23 TC 16 Z9 16 U1 1 U2 2 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD DEC PY 1999 VL 70 IS 6 BP 882 EP 886 DI 10.1111/j.1751-1097.1999.tb08297.x PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 266KZ UT WOS:000084300300008 ER PT J AU Crombie, MK Gillies, RR Arvidson, RE Brookmeyer, P Weil, GJ Sultan, M Harb, M AF Crombie, MK Gillies, RR Arvidson, RE Brookmeyer, P Weil, GJ Sultan, M Harb, M TI An application of remotely derived climatological fields for risk assessment of vector-borne diseases: A spatial study of filariasis prevalence in the Nile delta, Egypt SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID SOIL-WATER CONTENT; LYMPHATIC FILARIASIS; SURFACE-TEMPERATURE; VEGETATION INDEXES; EVAPOTRANSPIRATION; TRANSMISSION; LANDSCAPE; COVER; NDVI AB This paper applies a relatively straight forward remote sensing method that is commonly used to derive climatological variables. Measurements of surface reflectance and surface radiant temperature derived from Landsat Thematic Mapper data were used to create maps of fractional vegetation and surface soil moisture availability for the southern Nile delta in Egypt. These climatological variables were subsequently used to investigate the spatial distribution of the vector borne disease Bancroftian filariasis in the Nile delta where it is focally endemic and a growing problem. Averaged surface soil moisture values, computed for a 5-km border area around affected villages, were compared to filariasis prevalence rates. Prevalence rates were found to be negligible below a critical soil moisture value of 0.2, presumably because of a lack of appropriate breeding sites for the Culex Pipiens mosquito species. With appropriate modifications to account for local conditions and vector species, this approach should be useful as a means to map, predict, and control insect vector-borne diseases that critically depend on wet areas for propagation. This type of analysis may help governments and health agencies that are involved in filariasis control to better focus limited resources to identifiable "high-risk" areas. C1 Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Utah State Univ, Dept Plants Soils & Biometeorol, Logan, UT 84322 USA. Utah State Univ, Dept Geog & Earth Resources, Logan, UT 84322 USA. Washington Univ, Sch Med, Dept Med, Div Infect Dis, St Louis, MO 63130 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Govt Egypt, Minist Hlth, Cairo, Egypt. RP Crombie, MK (reprint author), Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. RI Gillies, Robert/C-1309-2010 NR 34 TC 17 Z9 17 U1 1 U2 1 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD DEC PY 1999 VL 65 IS 12 BP 1401 EP 1409 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 262ZV UT WOS:000084098900009 ER PT J AU Romano, LT Van de Walle, CG Krusor, BS Lau, R Ho, J Schmidt, T Ager, JW Gotz, W Kern, RS AF Romano, LT Van de Walle, CG Krusor, BS Lau, R Ho, J Schmidt, T Ager, JW Gotz, W Kern, RS TI Effect of Si doping on the strain and defect structure of GaN thin films SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE residual stress; GaN films; dislocations ID RELAXATION; SAPPHIRE; STRESS AB The amount of strain was measured in GaN films using X-ray diffraction, Raman, and curvature techniques as a function of film thickness and the Si doping concentration. It was found that for a doping concentration of 2 x 10(19), the threshold thickness for crack formation was about 2.5 mu m. Transmission electron microscopy observations showed that cracking proceeds without plastic deformation (i.e., no dislocation motion), and occurs catastrophically along the low-energy {1 (1) under bar 0 0} cleavage plane of GaN. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Hewlett Packard Co, Div Optoelect, San Jose, CA 95131 USA. RP Romano, LT (reprint author), Xerox Corp, Palo Alto Res Ctr, 3333 Coyote Hill Rd, Palo Alto, CA 94304 USA. EM romano@parc.xerox.com RI Van de Walle, Chris/A-6623-2012; OI Van de Walle, Chris/0000-0002-4212-5990; Ager, Joel/0000-0001-9334-9751 NR 12 TC 6 Z9 6 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 50 EP 53 DI 10.1016/S0921-4526(99)00404-4 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200010 ER PT J AU Colton, JS Yu, PY Teo, KL Perlin, P Weber, ER Grzegory, I Uchida, K AF Colton, JS Yu, PY Teo, KL Perlin, P Weber, ER Grzegory, I Uchida, K TI Selective excitation of the yellow luminescence of GaN SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE gallium nitride; yellow luminescence; selective excitation; donor-acceptor pair complexes ID UNDOPED GAN; FILMS; PHOTOLUMINESCENCE; VACANCIES; EPITAXY AB The yellow luminescence of n-type GaN has been studied with selective excitation using a combination of Ar(+) -ion and dye lasers, Narrower structures whose peak energies follow the excitation photon energy over the width of the yellow luminescence have been observed. Unlike the yellow luminescence excited by the above band gap excitations, these fine structures exhibit thermal activated quenching behavior. We propose that these fine structures are due to emission occurring at complexes of shallow donors and deep accepters which can be resonantly excited by photons with energies below the band gap. The activation energy deduced from their intensity is that for delocalization of electrons out of the complexes. Our results therefore suggest that there is more than one recombination channel (usually assumed to be due to distant donor-acceptor pairs) to the yellow luminescence in GaN. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Natl Univ Singapore, Dept Elect Engn, Singapore 119260, Singapore. Polish Acad Sci, UNIPRES, High Pressure Res Ctr, PL-01142 Warsaw, Poland. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Electrocommun, Dept Commun & Syst, Chofu, Tokyo 182, Japan. RP Colton, JS (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM colton@socrates.berkeley.edu RI Teo, Kie Leong/B-1921-2008; OI Teo, Kie Leong/0000-0001-5073-4510 NR 21 TC 8 Z9 8 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 75 EP 79 DI 10.1016/S0921-4526(99)00410-X PG 5 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200016 ER PT J AU Wetzel, C Ager, JW Topf, M Meyer, BK Amano, H Akasaki, I AF Wetzel, C Ager, JW Topf, M Meyer, BK Amano, H Akasaki, I TI Correlation of vibrational modes and DX-like centers in GaN : O SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE local vibration mode; oxygen in GaN; DX-center ID GALLIUM NITRIDE; HYDROSTATIC-PRESSURE; ALUMINUM NITRIDE; LIGHT EMITTERS; SEMICONDUCTORS; OXYGEN AB Vibrational modes in O-doped GaN have been observed at 544 cm(-1) in Raman spectroscopy. Under perturbation of large hydrostatic pressure the mode appears as a set of three different lines Q(1...3) whose relative intensities change by pressure. A switching between the modes occurs near 10 and 20 GPa and is found to correlate with the electron capture process to the DX-like state of O. We employ a simple oscillator model to predict the vibrational frequencies of O(N) A localization energy of 23 cm(-1) with respect to the optical phonon band is predicted. This is in reasonable agreement with the observed vibrational frequencies. Therefore, we assign the Q modes to the local vibration of O on N site in GaN. Modes Q(1...3) are tentatively assigned to three different charge states of the O defect center. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Meijo Univ, High Tech Res Ctr, Dept Elect & Elect Engn, Tempaku Ku, Nagoya, Aichi 4688502, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Giessen, Inst Phys 1, D-35392 Giessen, Germany. RP Wetzel, C (reprint author), Meijo Univ, High Tech Res Ctr, Dept Elect & Elect Engn, Tempaku Ku, 1-501 Shiogamaguchi, Nagoya, Aichi 4688502, Japan. EM wetzel@meijo-u.ac.jp RI Wetzel, Christian/O-4017-2014; OI Wetzel, Christian/0000-0002-6055-0990; Ager, Joel/0000-0001-9334-9751 NR 21 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 109 EP 112 DI 10.1016/S0921-4526(99)00418-4 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200024 ER PT J AU Liliental-Weber, Z Benamara, M Swider, W Washburn, J Grzegory, I Porowski, S Dupuis, RD Eiting, CJ AF Liliental-Weber, Z Benamara, M Swider, W Washburn, J Grzegory, I Porowski, S Dupuis, RD Eiting, CJ TI Ordering in bulk GaN : Mg samples: defects caused by Mg doping SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE Mg doping; ordering; polytypoids; polarity; pinholes; nanotubes ID ALUMINUM NITRIDE; OXYGEN; POLYTYPOIDS AB Transmission electron microscopy studies show evidence of spontaneous ordering in Mg-doped, bulk GaN crystals grown by a high-pressure and high-temperature process. The ordering consists of Mg-rich planar defects on basal planes separated by 10.4 nm and occurs only for growth in the N to Ga polar direction (0 0 0 (1) over bar N polarity). These planar defects show characteristics of inversion domains and have a 1/3[ 1 (1) over bar 0 0] + c/2 shift vector. These monolayers are polytypoids. A model for these defects is suggested. No similar defects are formed on the opposite site of the crystal (Ga to N polar direction), where the growth rate is an order of magnitude faster compared to the growth with N-polarity, but pyramidal and rectangular defects, empty inside (pinholes) are observed. The same types of defects seen for the two growth polarities in the bulk crystals were also observed in MOCVD grown GaN samples with Mg delta doping, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Polish Acad Sci, High Pressure Res Ctr Unipress, Warsaw, Poland. Univ Texas, Microelect Res Ctr, Austin, TX 78712 USA. RP Liliental-Weber, Z (reprint author), Lawrence Berkeley Natl Lab, MS 62-203,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM z_liliental-weber@lbl.gov RI Liliental-Weber, Zuzanna/H-8006-2012 NR 16 TC 30 Z9 30 U1 3 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 124 EP 129 DI 10.1016/S0921-4526(99)00422-6 PG 6 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200028 ER PT J AU McHugo, SA Thompson, AC Lamble, G Flink, C Weber, ER AF McHugo, SA Thompson, AC Lamble, G Flink, C Weber, ER TI Metal impurity precipitates in silicon: chemical state and stability SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE silicon; defects; transition metals; X-ray analysis ID FE; INTERFACE; DEFECTS; IRON AB The chemical state and the stability of metal precipitates in silicon have been studied using synchrotron-based X-ray fluorescence and absorption, Specifically, we have studied the stability and chemical nature of iron and copper impurities in single and polycrystalline silicon. In polycrystalline silicon material, we observe the presence of iron oxide or silicate precipitates at dislocations. Furthermore, our results demonstrate dissolution of copper precipitates from oxygen precipitates and their growth-related defects. Based on these results, we suggest oxygen in silicon can complex and stabilize only some metal impurities, depending on the formation energies of the metal oxide compounds. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP McHugo, SA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, MS 2-400,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM samchugo@lbl.gov NR 15 TC 17 Z9 17 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 371 EP 374 DI 10.1016/S0921-4526(99)00480-9 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200086 ER PT J AU Istratov, AA Hieslmair, H Weber, ER AF Istratov, AA Hieslmair, H Weber, ER TI What do we know about iron in silicon after 45 yr of research SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE iron; silicon; iron-boron pairs; iron oxide; iron silicate; oxygen ID INTERSTITIAL IRON; PRECIPITATION; SOLUBILITY; DIFFUSION; KINETICS; PAIRS AB Iron is the most investigated metallic impurity in crystalline silicon. It is thought that the fundamental physical properties of Fe in Si, such as diffusivity, solubility, and reaction constants of pairing with baron, are firmly established. However, our analysis shows that there remains a good deal of contradiction in the literature data, and that the uncertainty of the reaction constants is too large for quantitative predictive simulations of iron defect reactions, such as gettering simulations. Possible reasons for discrepancies in the literature data are discussed, and improved measurement procedures are suggested. Finally, the current state of understanding of the reactions of iron to form iron oxides and silicates, which may be responsible for lifetime-killing intragranular defects in solar cells, is discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Istratov, AA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 62-203,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM istratov@socrates.berkeley.edu OI Hieslmair, Henry/0000-0002-5842-1882 NR 25 TC 1 Z9 1 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 412 EP 415 DI 10.1016/S0921-4526(99)00493-7 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200096 ER PT J AU Flink, C Feick, H McHugo, SA Mohammed, A Seifert, W Hieslmair, H Heiser, T Istratov, AA Weber, ER AF Flink, C Feick, H McHugo, SA Mohammed, A Seifert, W Hieslmair, H Heiser, T Istratov, AA Weber, ER TI Formation of copper precipitates in silicon SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE silicon; copper; precipitation formation ID DIFFUSION AB The formation of copper precipitates in silicon was studied after high-temperature intentional contamination of p- and n-type FZ and Cz-grown silicon and quench to room temperature. With the Transient Ion Drift (TID) technique on p-type silicon a critical Fermi level position at E(C)-0.2 eV was found. Only if the Fermi level position, which is determined by the concentrations of the accepters and the copper donors, surpasses this critical value precipitation takes place. If the Fermi level is below this level the supersaturated interstitial copper diffuses out. An electrostatic precipitation model is introduced that correlates the observed precipitation behavior with the electrical activity of the copper precipitates as detected with Deep Level Transient Spectroscopy (DLTS) on n-type and with Minority Carrier Transient Spectroscopy (MCTS) on p-type silicon. (C) 1999 Elsevier Science B.V, All rights reserved. C1 Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Flink, C (reprint author), Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. EM cflink@lbl.gov OI Hieslmair, Henry/0000-0002-5842-1882 NR 12 TC 9 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 437 EP 440 DI 10.1016/S0921-4526(99)00499-8 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200102 ER PT J AU Hieslmair, H Istratov, AA Flink, C McHugo, SA Weber, ER AF Hieslmair, H Istratov, AA Flink, C McHugo, SA Weber, ER TI Experiments and computer simulations of iron profiles in p/p(+) silicon: segregation and the position of the iron donor level SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE iron; donor level; heavily doped silicon; segregation ID BORON-DOPED SILICON; SOLUBILITY AB The position of the iron donor trap level in the silicon band gap at processing temperatures determines numerous important properties of iron such as its solubility and effective diffusivity. Thus this position influences the time and efficiency of the widely used p/p(+) segregation gettering, i.e. the removal of iron from an epitaxial p-type silicon layer (the device region) by a heavily p(+)-doped silicon substrate, In this work, the iron concentration profiles within a 70 mu m p-type epitaxial layer on a p(+)-type substrate were quantitatively measured using deep level transient spectroscopy in order to determine the position of the iron donor level. The samples are first intentionally contaminated with iron at 920 degrees C and then annealed at 472 degrees C for various times. The measured iron profiles are fitted with computer simulations in order to determine the iron trap level and the segregation coefficient at 472 degrees C, The results indicate that the iron trap level is at Ev + 0.32 eV at 472 degrees C. The results of this study and of previous studies indicate that the iron donor level decreases in proportion to the band-gap narrowing. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. RP Hieslmair, H (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 7-222,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM hhiesl@argon.berkeley.edu OI Hieslmair, Henry/0000-0002-5842-1882 NR 14 TC 15 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 441 EP 444 DI 10.1016/S0921-4526(99)00500-1 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200103 ER PT J AU Pennycook, SJ Chisholm, MF Yan, Y Duscher, G Pantelides, ST AF Pennycook, SJ Chisholm, MF Yan, Y Duscher, G Pantelides, ST TI A combined experimental and theoretical approach to grain boundary structure and segregation SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE grain boundaries; atomic structure; impurities; segregation; transformation; electron microscopy; total energy calculations ID SCATTERED ELECTRONS; CORE STRUCTURES; RESOLUTION; CRYSTALS; MGO AB Recently, the scanning transmission electron microscope has become capable of forming electron probes of atomic dimensions. Through the technique of Z-contrast imaging, it is now possible to form atomic resolution images with high compositional sensitivity from which atomic column positions can be directly determined. An incoherent image of this nature also allows atomic resolution chemical analysis to be performed, by locating the probe over particular columns or planes seen in the image while electron energy loss spectra are collected. Such data represent either an ideal starting point for first-principles theoretical calculations or a test of theoretical predictions. We present several examples where theory and experiment together give a very complete and often surprising atomic scale view of complex materials. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Pennycook, SJ (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. EM pky@ornl.gov RI Duscher, Gerd/G-1730-2014 OI Duscher, Gerd/0000-0002-2039-548X NR 23 TC 9 Z9 9 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 453 EP 457 DI 10.1016/S0921-4526(99)00521-9 PG 5 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200106 ER PT J AU Yarykin, N Cho, CR Zuhr, R Rozgonyi, G AF Yarykin, N Cho, CR Zuhr, R Rozgonyi, G TI In-situ studies of point-defect complexes in silicon implanted with heavy MeV ions SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE silicon; ion implantation; defects; deep levels AB In-situ deep-level transient spectroscopy measurements have been performed on silicon implanted with MeV ions at 85 K. It is observed that the implantation of heavier ions results in the formation of novel deep-level centers; their formation/annealing kinetics and depth distributions are studied. Divacancy formation in silicon implanted with Si(+) and Ge(+) MeV ions is found to occur at higher temperatures than expected from the isolated vacancy mobility, and to exhibit a strong dependence on the electrical bias applied during annealing. The phenomena are discussed under the assumption that vacancies and interstitials are trapped in clusters/disorder regions immediately after low-temperature implantation of heavier ions, and are released during subsequent annealing. (C) 1999 Elsevier Science B.V. All rights reserved. C1 N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27965 USA. Russian Acad Sci, Inst Microelect Technol, Chernogolovka 142432, Moscow Region, Russia. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Yarykin, N (reprint author), N Carolina State Univ, Dept Mat Sci & Engn, Box 7907, Raleigh, NC 27965 USA. EM nay@ipmt_hpm.ac.ru RI Yarykn, Nikolai/C-7277-2014 NR 12 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 485 EP 488 DI 10.1016/S0921-4526(99)00531-1 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200113 ER PT J AU Tarasov, I Ostapenko, S Feifer, V McHugo, S Koveshnikov, SV Weber, J Haessler, C Reisner, EU AF Tarasov, I Ostapenko, S Feifer, V McHugo, S Koveshnikov, SV Weber, J Haessler, C Reisner, EU TI Defect diagnostics using scanning photoluminescence in multicrystalline silicon SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE silicon; photoluminescence; dislocation; defects AB Scanning room-temperature photoluminescence (PL) spectroscopy was applied to multicrystalline silicon (mc-Si) wafers to assess electronic properties of the high-quality solar grade material. The intensity of band-to-band emission with the maximum at 1.09 eV measured across entire me-Si wafer positively correlates with minority carrier lifetime measured concurrently using laser-microwave reflection technique. We have found in me-Si wafers an intense "defect" PL band with the maximum at about 0.8 eV and half-width of similar to 75 meV at room temperature. It is strongly localized in "bad" areas possessing a reduced by a factor of two orders band-to-band PL intensity and a noticeable degraded lifetime. High-resolution PL mapping of the 0.8 eV band revealed a link to areas with high dislocation density. PL spectra down to 4.2 K were measured in regions with high and low "defect" band intensity demonstrating a correlation of the 0.8 eV band with distribution of the D3/D4 dislocation lines, The origin of the 0.8 eV band is discussed in a connection with dislocation network. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ S Florida, Ctr Microelect Res, Tampa, FL 33620 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source Ctr, Berkeley, CA 94720 USA. SEH Amer Inc, Vancouver, WA 98682 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Bayer AG, D-47829 Krefeld, Germany. RP Ostapenko, S (reprint author), Univ S Florida, Ctr Microelect Res, 4202 E Fowler Ave, Tampa, FL 33620 USA. EM ostapenk@eng.usf.edu NR 7 TC 15 Z9 15 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 549 EP 552 DI 10.1016/S0921-4526(99)00570-0 PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200129 ER PT J AU Kim, H Rodriguez, S Grimsditch, M Anthony, TR Ramdas, AK AF Kim, H Rodriguez, S Grimsditch, M Anthony, TR Ramdas, AK TI Jahn-Teller splitting and Zeeman effect of acceptors in diamond SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE Jahn-Teller splitting; Zeeman effect acceptors; diamond ID ISOTOPICALLY CONTROLLED DIAMONDS; ELECTRONIC RAMAN; INFRARED-SPECTRA; SPHERICAL MODEL; SEMICONDUCTORS; STATES AB Employing the high resolution of a 5 + 4 tandem Fabry-Perot interferometer, we discovered that Delta', the Raman active electronic transition between the spin-orbit split 1s(p(3/2)): Gamma(8) and 1s(p(1/2)): Gamma(7) acceptor ground states, is a doubler for a boron impurity in diamond with a clearly resolved spacing of 0.81 +/- 0.15cm(-1). The direct observation of a Stokes/anti-Stokes pair with 0.80 +/- 0.04 cm(-1) shift provides a striking confirmation that the lower 1s(p(3/2)): Gamma(8) ground state has experienced a splitting due to a static Jahn-Teller distortion. The Zeeman effect of Delta' has been investigated with a magnetic field along several crystallographic directions. Theory of the Zeeman effect, formulated in terms of the symmetry of the substitutional acceptor and the Luttinger parameters of the valence band, allows quantitative predictions of the relative intensities of the Zeeman components in full agreement with experiments. The observation of transitions within the Gamma(8) Zeeman multiplet, i.e., the Raman-electron-paramagnetic-resonances, is yet another novel feature to emerge from the present study. The investigation has also yielded g-factors characterizing the Zeeman multiplets. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. GE, Corp Res & Dev, Schenectady, NY 12309 USA. RP Kim, H (reprint author), Argonne Natl Lab, Adv Photon Source, B4202,XFD-401,9700 S Cass Ave, Argonne, IL 60439 USA. EM hjk@physics.purdue.edu NR 12 TC 4 Z9 4 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 624 EP 627 DI 10.1016/S0921-4526(99)00589-X PG 4 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200146 ER PT J AU Zhang, SB Wei, SH Zunger, A AF Zhang, SB Wei, SH Zunger, A TI Overcoming doping bottlenecks in semiconductors and wide-gap materials SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 20th International Conference on Defects in Semiconductors (ICDS-20) CY JUL 26-30, 1999 CL BERKELEY, CA SP Air Force Off Sci Res, Amer Xtal Technol Inc, Appl Mat Inc, Bell Labs Lucent Technol, Hewlett Packard Lab, IBM, Intel Corp, Lawrence Berkeley Natl Lab, Off Naval Res, Sula Technol, Xeeox Palo Alto Res Ctr DE doping; defect compensation; wide-gap materials; semiconductors ID MOLECULAR-BEAM EPITAXY; NATIVE DEFECTS; II-VI; ELECTRONIC-STRUCTURE; ALXGA1-XAS ALLOYS; DX CENTERS; GAAS; COMPENSATION; MECHANISM; ENERGIES AB There often exist strong doping bottlenecks that may severely restrict potential applications of semiconductors, especially in wide-band-gap materials where bipolar doping is impossible. Recent rapid progress in semiconductor research has reached a point where these doping limitations must be overcome in order to tune semiconductors for precisely required properties. Here, we discuss how to find out what causes the doping bottlenecks. We based our discussion on a set of recent, novel developments regarding the doping limitations: the "doping limit rule" distilled from both phenomenological studies and from first-principles calculations. The thermodynamic doping bottlenecks are identified as due mainly to the formation of intrinsic defects whose formation enthalpies depend on the Fermi energy, and always act to negate the effect of doping. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Zhang, SB (reprint author), Natl Renewable Energy Lab, 1617 Cole Bldg, Golden, CO 80401 USA. EM szhang@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 33 TC 29 Z9 30 U1 3 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD DEC PY 1999 VL 273-4 BP 976 EP 980 DI 10.1016/S0921-4526(99)00605-5 PG 5 WC Physics, Condensed Matter SC Physics GA 268ZX UT WOS:000084452200232 ER PT J AU Verebelyi, DT Schneider, CW Kuo, YK Skove, MJ Tessema, GX Payne, JE AF Verebelyi, DT Schneider, CW Kuo, YK Skove, MJ Tessema, GX Payne, JE TI Effect of magnetic substitutions (Ni, Co, Fe) for Cu on thermal conductivity of BiSCCO whiskers SO PHYSICA C LA English DT Article DE thermal conductivity; Bi-2212; BiSCCO; whiskers ID SINGLE-CRYSTAL; TEMPERATURE SUPERCONDUCTORS; UNTWINNED YBA2CU3O7-DELTA; O SUPERCONDUCTORS; AB PLANE; BI2SR2CACU2O8; INPLANE; HEAT AB We have measured the thermal conductivity kappa of Bi-2(SrCa)(3)(Cu1-xTx) O-y (T = Ni,Co,Fe) whiskers containing up to 1.5% Substitution for Cu. Increased substitution suppresses both T-c and the usual enhancement of kappa seen below T-c in undoped samples. Additionally, substitution strongly decreases thermal transport by carriers which reveals the phonon thermal conductivity of Bi-2(SrCa)(3)Cu2Oy. The phonon contribution was found to be glass-like and when subtracted from the measured kappa allows a fit of the electronic thermal conductivity to a phenomenological model that includes partial condensation of carriers in Bi-2(SrCa)(3)Cu2Oy. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. S Carolina State Univ, Dept Phys Sci, Orangeburg, SC 29117 USA. RP Verebelyi, DT (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 39 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD DEC 1 PY 1999 VL 328 IS 1-2 BP 53 EP 59 DI 10.1016/S0921-4534(99)00536-5 PG 7 WC Physics, Applied SC Physics GA 267UJ UT WOS:000084377400007 ER PT J AU Allman, BE Lee, WT Motrunich, OI Werner, SA AF Allman, BE Lee, WT Motrunich, OI Werner, SA TI Scalar Aharonov-Bohm effect with longitudinally polarized neutrons SO PHYSICAL REVIEW A LA English DT Article ID CASHER PHASE; ATOMIC SYSTEM; INTERFEROMETRY; INTERFERENCE; FIELD; PARTICLES AB In the scalar Aharonov-Bohm effect, a charged particle (electron) interacts with the scaler electrostatic potential U in the field-foe (i.e., force-free) region inside an electrostatic cylinder (Faraday cage). Using a perfect single-crystal neutron interferometer we have performed a ''dual'' scalar Aharonov-Bohm experiment by subjecting polarized thermal neutrons to a pulsed magnetic field. The pulsed magnetic field was spatially uniform, precluding any force on the neutrons. Aligning the direction of the pulsed magnetic field to the neutron magnetic moment also rules out any classical torque acting to change the neutron polarization. The observed phase shift is purely quantum mechanical in origin. A detailed description of the experiment, performed at the University of Missouri Research Reactor, and its interpretation is given in this paper. [S1050-2947(99)02310-0]. C1 Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Univ Missouri, Res Reactor Ctr, Columbia, MO 65211 USA. RP Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. NR 44 TC 7 Z9 7 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD DEC PY 1999 VL 60 IS 6 BP 4272 EP 4284 DI 10.1103/PhysRevA.60.4272 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000014 ER PT J AU Schwindt, PDD Kwiat, PG Englert, BG AF Schwindt, PDD Kwiat, PG Englert, BG TI Quantitative wave-particle duality and nonerasing quantum erasure SO PHYSICAL REVIEW A LA English DT Article ID PODOLSKY-ROSEN CHANNELS; INTERFERENCE EXPERIMENT; COMPLEMENTARITY; ERASER; STATES; LIGHT; INTERFEROMETER; COMMUNICATION; ABSORPTION; COHERENCE AB The notion of wave-particle duality may be quantified by the inequality V-2 + K-2 less than or equal to 1, relating interference fringe visibility V, and path knowledge K. With a single-photon interferometer in which-polarization is used to label the paths, we have investigated the relation for various situations, including pure, mixed, and partially mixed input states. A quantum-eraser scheme has been realized that recovers interference fringes even when no which way information is available to erase. [S1050-2947(99)02911-X]. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RP Kwiat, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, P-23, Los Alamos, NM 87545 USA. RI Englert, Berthold-Georg/G-2286-2012 OI Englert, Berthold-Georg/0000-0002-0690-927X NR 39 TC 98 Z9 100 U1 1 U2 9 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 DEC PY 1999 VL 60 IS 6 BP 4285 EP 4290 DI 10.1103/PhysRevA.60.4285 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000015 ER PT J AU Suzuki, S Shimakura, N Gu, JP Hirsch, G Buenker, RJ Kimura, M Stancil, PC AF Suzuki, S Shimakura, N Gu, JP Hirsch, G Buenker, RJ Kimura, M Stancil, PC TI Electron capture and excitation collisions of Si2+ ions with He atoms at intermediate energies SO PHYSICAL REVIEW A LA English DT Article ID CHARGE-TRANSFER; AB-INITIO; CI CALCULATIONS; HELIUM; SI4+; HYDROGEN; ABINITIO; CURVES; SI3+ AB We have investigated electron capture and excitation in collisions of Si2+ ions with He atoms in the collision energy range from 0.02-6 keV/u based on a molecular representation. Molecular states are determined by using the multireference single- and double-excitation configuration-interaction method. We have considered electron capture and excitation both by the ground singlet and metastable triplet Si2+ ions. The capture cross section by the ground singlet Si2+ ion increases with increasing collision energy and reaches a value of similar to 1.5 x 10(-16) cm(2), while that by the metastable triplet ion is found to be large with a magnitude of 4 x 10(-16) cm(2) at the highest energy studied. Weak but conspicuous oscillatory structures are found for both cases, which are due to multichannel interference. The present rate coefficient for the ground singlet Si2+ ion impact is found to be much smaller than those of the [Si4+ + He] system studied earlier. [S1050-2947(99)01311-6]. C1 Niigata Univ, Fac Sci, Niigata 95021, Japan. Berg Univ Gesamthsch Wuppertal, D-42097 Wuppertal, Germany. Yamaguchi Univ, Sch Med, Ube, Yamaguchi 755, Japan. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Suzuki, S (reprint author), Niigata Univ, Fac Sci, Niigata 95021, Japan. NR 31 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD DEC PY 1999 VL 60 IS 6 BP 4504 EP 4509 DI 10.1103/PhysRevA.60.4504 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000042 ER PT J AU Fursa, DV Trajmar, S Bray, I Kanik, I Csanak, G Clark, REH Abdallah, J AF Fursa, DV Trajmar, S Bray, I Kanik, I Csanak, G Clark, REH Abdallah, J TI Integral cross sections for electron scattering by ground-state Ba atoms SO PHYSICAL REVIEW A LA English DT Article ID BARIUM VAPOR LASERS; ELASTIC-SCATTERING; PLASMA CLOUDS; IMPACT; EXCITATION; STRONTIUM; IONIZATION; CALCIUM AB We have used the convergent close-coupling method and a unitarized first-order many-body theory to calculate integral cross sections for elastic scattering and momentum transfer, for excitation of the 5d(21)S, 6s6p(1)P(1), 6s7p(1)P(1), 6s8p(1)P(1), 6s5d(1)D(2), 5d(21)D(2), 6S6d(1)D(2), 6p5d(1)F(3), 6s4f(1)F(3), 6p5d(1)D(2), 6s6p(3)P(0,1,2), 6s5d(3)D(1,2,3), and 6p5d(3)D(2) states, for ionization and for total scattering by electron impact on the ground state of barium at incident electron energies from 1 to 1000 eV. These results and all available experimental data have been combined to produce a recommended set of integral cross sections. [S1050-2947(99)02912-1]. C1 Flinders Univ S Australia, Adelaide, SA 5001, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fursa, DV (reprint author), Flinders Univ S Australia, GPO Box 2100, Adelaide, SA 5001, Australia. RI Fursa, Dmitry/C-2301-2009; Bray, Igor/B-8586-2009 OI Fursa, Dmitry/0000-0002-3951-9016; Bray, Igor/0000-0001-7554-8044 NR 38 TC 12 Z9 13 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD DEC PY 1999 VL 60 IS 6 BP 4590 EP 4599 DI 10.1103/PhysRevA.60.4590 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000052 ER PT J AU LeBrun, T Southworth, SH Armen, GB MacDonald, MA Azuma, Y AF LeBrun, T Southworth, SH Armen, GB MacDonald, MA Azuma, Y TI Radiationless resonant Raman scattering at the Ar K edge SO PHYSICAL REVIEW A LA English DT Article ID INNER-SHELL PHOTOIONIZATION; POST-COLLISION INTERACTION; SYNCHROTRON RADIATION; POSTCOLLISION-INTERACTION; QUANTUM-THEORY; ARGON; ELECTRON; THRESHOLD; SPECTRA; FLUORESCENCE AB Partial cross sections for Ar K-L2L3(D-1(2))np, n=4 and 5 spectator Auger states excited by x-ray absorption across the K edge, were measured and compared with calculations based on the theory of radiationless resonant Raman scattering. Core relaxation and coherence among bound and continuum intermediate states produce shake-up, shake-down, and photoelectron-recapture effects in the cross sections. The width and position of the 4p spectator Auger peak are shown to be sensitive to resonance structure in the partial cross section via averaging over the x-ray bandwidth. [S1050-2947(99)09712-7]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Tennessee, Knoxville, TN 37996 USA. SERC, Daresbury Lab, CLRC, Warrington WA4 4AD, Cheshire, England. KEK, IMSS, Photon Factory, Tsukuba, Ibaraki 3050801, Japan. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 25 TC 23 Z9 23 U1 0 U2 4 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 DEC PY 1999 VL 60 IS 6 BP 4667 EP 4672 DI 10.1103/PhysRevA.60.4667 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000059 ER PT J AU Zhao, X Crane, SG Guckert, R Vieira, DJ AF Zhao, X Crane, SG Guckert, R Vieira, DJ TI Hyperfine structure and isotope shift of Rb-82 D-1 and D-2 transitions SO PHYSICAL REVIEW A LA English DT Article ID ATOMS; RUBIDIUM AB We report on the hyperfine-structure measurements of the 5 P-1/2 and 5 P-3/2 states as well as the isotope shift of the D-1 transition of radioactive Rb-82 (t(1/2)=75 s) atoms trapped in a magneto-optical trap. The systematic effects of light shift (ac Stark shift) and power broadening were explored to verify the accuracy of our trap and probe method against saturation spectroscopy results in Rb-85. The hyperfine-splitting magnetic-dipole coefficient (A) for the Rb-82 5P(1/2) State and the isotope shift of the D1 transition (delta v(82-85)) was measured to be 122.7(1.0) MHz and -150.8(2.0) MHz, respectively. The hyperfine splitting for the Rb-82 5P(3/2) state was determined to be 90.3(1.5) MHz in agreement with the previous measurement of 89.3(9.0) MHz [C. Thibault et al., Phys. Rev. C 23, 2720 (1981)]. These measurements provide key information that is needed to manipulate and determine the polarization of trapped Rb-82 atoms for a parity violating beta-asymmetry measurement. [S1050-2947(99)01012-4]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Utah State Univ, Dept Phys, Logan, UT 84322 USA. RP Zhao, X (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 11 TC 7 Z9 7 U1 1 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 DEC PY 1999 VL 60 IS 6 BP 4730 EP 4733 DI 10.1103/PhysRevA.60.4730 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000066 ER PT J AU Gulley, MS Zhao, XM Bryant, HC Strauss, CEM Funk, DJ Stintz, A Rislove, DC Kyrala, GA Ingalls, WB Miller, WA AF Gulley, MS Zhao, XM Bryant, HC Strauss, CEM Funk, DJ Stintz, A Rislove, DC Kyrala, GA Ingalls, WB Miller, WA TI Nonresonant excess photon detachment of negative hydrogen ions SO PHYSICAL REVIEW A LA English DT Article ID MULTIPHOTON DETACHMENT; 2-PHOTON DETACHMENT; ANGULAR-DISTRIBUTIONS; 3-PHOTON DETACHMENT; IONIZATION; ELECTRON; HALOGENS; FIELD; PHOTODETACHMENT; ABSORPTION AB One-photon detachment and two-photon nonresonant excess photon detachment of electrons from the H- ion (outer-electron binding energy = 0.7542 eV) are observed with 1.165 eV laser pulses from a Nd:YAG laser (where YAG denotes yttrium aluminum garnet). A Penning ion source produces a pulsed 8 mu A, 35 keV H- beam that intersects a laser beam cylindrically focused down to a 17 mu m full width at half maximum waist in the ion beam direction, creating a high-intensity interaction region with peak intensities of up to 10(11) W/cm(2). The interaction time is 7 ps. The detached electrons are detected by a time-of-flight apparatus. enabling us to detect a very small two-photon signal in the presence of a very large signal from single photon detachments. By rotating the linear polarization angle, we study the angular distribution of the electrons for both one- and two-photon detachments. The spectra are modeled to determine the asymmetry parameters and one- and two-photon cross sections. We find beta(2) to be 2.54+0.44/-0.60 and beta(4) to be 2.29+0.07/-0.31, corresponding to a D state of 89+3/-12% of the S wave and D wave detachments for the two-photon results. The relative phase angle between the S and D amplitudes is measured to be less than 59 degrees. The measured cross sections are found to be consistent with theoretical predictions. The one-photon photodetachment cross section is measured to be (3.6+/-1.7)x10(-17) cm(2) The two-photon photodetachment generalized cross section is (1.3+/-0.5)x10(-48) cm(4) sec, consistent with theoretical calculations of the cross section. The three-photon generalized cross section is less than 4.4x10(-79) cm(6) sec(2). [S1050-2947(99)02812-7]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. RP Gulley, MS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 40 TC 7 Z9 7 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 DEC PY 1999 VL 60 IS 6 BP 4753 EP 4763 DI 10.1103/PhysRevA.60.4753 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000070 ER PT J AU Yatsenko, LP Shore, BW Halfmann, T Bergmann, K Vardi, A AF Yatsenko, LP Shore, BW Halfmann, T Bergmann, K Vardi, A TI Source of metastable H(2s) atoms using the Stark chirped rapid-adiabatic-passage technique SO PHYSICAL REVIEW A LA English DT Article ID POPULATION TRANSFER; HYDROGEN; GENERATION; RADIATION; KRYPTON; STATES; VAPOR; LASER AB We propose the use of Stark chirped rapid-adiabatic-passage method, a technique in which the energy of a target state is swept through resonance by a slowly varying dynamic Stark shift to induce complete population transfer from the ground 1s state to the metastable 2s state of the hydrogen atom. Parasitic ionization processes are strongly reduced by using a two-color excitation scheme. Our detailed numerical calculations show that under judicious choice of pulse parameters, up to 98% of the population can be found in the 2s state at the end of the process. [S1050-2947(99)51112-8]. C1 Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Ukrainian Acad Sci, Inst Phys, UA-252650 Kiev, Ukraine. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Yatsenko, LP (reprint author), Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. RI Vardi, Amichay/D-8189-2011; Halfmann, Thomas/O-4588-2014; BERGMANN, KLAAS/D-5543-2011 OI Vardi, Amichay/0000-0002-8992-2129; Halfmann, Thomas/0000-0002-1222-2669; NR 27 TC 55 Z9 55 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 DEC PY 1999 VL 60 IS 6 BP R4237 EP R4240 DI 10.1103/PhysRevA.60.R4237 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 263WJ UT WOS:000084148000008 ER PT J AU Evans, JSO Jorgensen, JD Short, S David, WIF Ibberson, RM Sleight, AW AF Evans, JSO Jorgensen, JD Short, S David, WIF Ibberson, RM Sleight, AW TI Thermal expansion in the orthorhombic gamma phase of ZrW2O8 SO PHYSICAL REVIEW B LA English DT Article ID PRESSURE; COMPRESSIBILITY; TEMPERATURE AB The thermal expansion of the orthorhombic gamma phase of ZrW2O8 has been measured using neutron powder diffraction from 4.6 to 410 K, where it transforms to the cubic ct phase. At low temperature, gamma-ZrW2O8 has a negative thermal expansion, but the thermal expansion becomes:less negative with increasing temperature and is slightly positive at room temperature. This behavior can be! explained in terms of the contributing phonon modes: At low temperature, the vibrational modes lead to a negative:thermal expansion, but additional modes that become active upon increasing temperature add positive contributions. Above room temperature, the a and b axes increase more sharply while the c axis reverses its behavior and decreases with increasing temperature. This unusual behavior can be explained in terms of a thermally activated process, presumed to result from oxygen-atom migration, that makes an additional contribution to the thermal expansion. [S0163-1829(99)03346-9]. C1 Univ Durham, Dept Chem, Univ Agr Labs, Durham DH1 3LE, England. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA. Oregon State Univ, Adv Mat Res Ctr, Corvallis, OR 97331 USA. RP Evans, JSO (reprint author), Univ Durham, Dept Chem, Univ Agr Labs, South Rd, Durham DH1 3LE, England. RI Evans, John/E-6345-2012; Ibberson, Richard/P-8397-2015 OI Evans, John/0000-0001-6305-6341; Ibberson, Richard/0000-0003-0007-706X NR 18 TC 30 Z9 32 U1 0 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 DEC 1 PY 1999 VL 60 IS 21 BP 14643 EP 14648 DI 10.1103/PhysRevB.60.14643 PG 6 WC Physics, Condensed Matter SC Physics GA 263TQ UT WOS:000084141700042 ER PT J AU Shen, Z Stoldt, CR Jenks, CJ Lograsso, TA Thiel, PA AF Shen, Z Stoldt, CR Jenks, CJ Lograsso, TA Thiel, PA TI Fine structure on flat surfaces of quasicrystalline Al-Pd-Mn SO PHYSICAL REVIEW B LA English DT Article ID ENERGY-ELECTRON DIFFRACTION; ICOSAHEDRAL QUASI-CRYSTALS; ALPDMN; PHASE; LEED; ALCUFE; STM AB We have analyzed the fine structure revealed by scanning tunneling microscopy for a flat (within 0.8 Angstrom) fivefold surface of i-Al-Pd-Mn. Even though features in the image appear to be arranged randomly, self-similar features are separated by distinct distances. The distribution of such distances is compatible with the separations between pseudo-Mackay icosahedra tangent to the topmost layer, and with separations between other cluster-based units. We propose that the fine structure is due to electronic structure imposed by the clusters. [S0163-1829(99)01035-8]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Shen, Z (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 30 TC 56 Z9 57 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 1 PY 1999 VL 60 IS 21 BP 14688 EP 14694 DI 10.1103/PhysRevB.60.14688 PG 7 WC Physics, Condensed Matter SC Physics GA 263TQ UT WOS:000084141700048 ER PT J AU Krishnan, KM Ju, HL AF Krishnan, KM Ju, HL TI Role of stoichiometry and structure in colossal magnetoresistive La1-xSrxMn1-yRuyO3+delta SO PHYSICAL REVIEW B LA English DT Article ID INSULATOR-METAL TRANSITION; GIANT MAGNETORESISTANCE; THIN-FILMS; ELECTRONIC-STRUCTURE; DOUBLE EXCHANGE; DOPED LAMNO3; LA1-XSRXMNO3; MANGANITES; LA0.7CA0.3MNO3; RESISTIVITY AB We have systematically investigated the effect of stoichiometry: [divalent doping (x), controlled oxygen content (delta) by vacuum annealing at elevated temperatures, and substitution (y) of Ru] and structure (substrate induced strain and its relaxation on annealing) on the magnetic/transport properties of the colossal magnetoresistive La1-xSrxMn1-yRuyO3+delta bulk and thin films prepared by both sol-gel and pulsed laser deposition techniques. The following results have been found: (1) Oxygen-reduced La0.7Sr0.3MnOz show a larger resistivity and lower T-c than the corresponding bulk materials. Moreover, their resistivity acid MR behavior can be precisely controlled by vacuum annealing and, in fact, they duplicate all the salient features observed in divalent-doped manganites. (2) The metal-insulator transitions Of thin films grown on lattice-matched substrates is observed to be a function of thickness due to the accommodation of epitaxial strain and the associated Mn-O-Mn bond-distortions. (3) Ru doped La0.7Sr0.3Mn1-yRuyO3, 0 less than or equal to y less than or equal to 0.2 samples show a surprisingly small decrease in T-c. This is attributed to the exceptional ability of Ru, unlike other substitutions in Mn sites, to stabilize magnetic ordering at elevated temperatures. (4) Oxygen K-edge (core level excitation of oxygen 1s electrons into empty p-like states) electron-energy-loss spectra of divalent-doped La1-xSrxMnO3 (0T-MI indicative of fluctuations in the gap above the MI transition. We use these results to discuss several models for the MI transition. [S0163-1829(99)01942-6]. C1 Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Booth, CH (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94708 USA. EM chbooth@lbl.gov RI Booth, Corwin/A-7877-2008 NR 21 TC 14 Z9 15 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 DEC 1 PY 1999 VL 60 IS 21 BP 14852 EP 14856 DI 10.1103/PhysRevB.60.14852 PG 5 WC Physics, Condensed Matter SC Physics GA 263TQ UT WOS:000084141700068 ER PT J AU Rosenkranz, S Medarde, M Fauth, F Mesot, J Zolliker, M Furrer, A Staub, U Lacorre, P Osborn, R Eccleston, RS Trounov, V AF Rosenkranz, S Medarde, M Fauth, F Mesot, J Zolliker, M Furrer, A Staub, U Lacorre, P Osborn, R Eccleston, RS Trounov, V TI Crystalline electric field of the rare-earth nickelates RNiO3 (R = Pr, Nd, Sm, Eu, and Pr1-xLax, 0 <= x <= 0.7) determined by inelastic neutron scattering SO PHYSICAL REVIEW B LA English DT Article ID METAL-INSULATOR-TRANSITION; RAY-ABSORPTION SPECTROSCOPY; PRESSURE-DEPENDENCE; PRNIO3; DIFFRACTION; NDNIO3; 6-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-7; PEROVSKITE; NDGAO3; GAP AB The rue-earth based nickelates RNiO3 (R=Pr, Nd, Sm, Eu, and Pr1-xLax, 0 less than or equal to x less than or equal to 0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R3+ site within the electronic ground-state J multiplet (for R=Pr, Nd, and Pr1-xLax) as well as within the two lowest-lying J multiplets (for R = Sm and Eu) were directly: observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over: the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments, Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF parameters in an effective point charge model failed, probably due to the strong covalency in these compounds. Across the structural transition occurring in Pr1-xLaxNiO3 at x = 0.7, a change in the symmetry of the CEF ground state is observed, which has a profound influence on the thermodynamic properties. [S0163-1829(99)01145-5]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. ETH Zurich, Neutron Scattering Lab, CH-5232 Villigen, Switzerland. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Paul Scherrer Inst, Swiss Light Source Project, CH-5232 Villigen, Switzerland. Univ Maine, CNRS 6010, UPRES A, Lab Fluorures, F-72085 Le Mans, France. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. Petersburg Nucl Phys Inst, Gatchina 188358, Russia. RP Rosenkranz, S (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011; Staub, Urs/C-4914-2015; Fauth, Francois/K-9643-2014 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383; Fauth, Francois/0000-0001-9465-3106 NR 33 TC 19 Z9 19 U1 0 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 1 PY 1999 VL 60 IS 21 BP 14857 EP 14867 DI 10.1103/PhysRevB.60.14857 PG 11 WC Physics, Condensed Matter SC Physics GA 263TQ UT WOS:000084141700069 ER PT J AU Bermejo, FJ Fak, B Bennington, SM Fernandez-Perea, R Cabrillo, C Dawidowski, J Fernandez-Diaz, MT Verkerk, P AF Bermejo, FJ Fak, B Bennington, SM Fernandez-Perea, R Cabrillo, C Dawidowski, J Fernandez-Diaz, MT Verkerk, P TI Microscopic collective dynamics in liquid para-H-2 SO PHYSICAL REVIEW B LA English DT Article ID COHERENT NEUTRON-SCATTERING; SOLID HYDROGEN; EXCITATIONS; DEUTERIUM; PRESSURE AB Well-defined phonons with strong anomalous (upward) dispersion are observed by inelastic neutron scattering in liquid para-H-2 at a temperature of 15.7 K. The damping, being very small for the low-e phonons, increases with wave vector Q, and only broad features are observed for Q greater than or similar to 1 Angstrom(-1). This behavior is shown to deviate strongly from results of molecular simulations of a fully classical analogue using a realistic potential. [S0163-1829(99)01245-X]. C1 CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. Comis Nacl Energia Atom, Dept Rech Fondamentale Mat Condensee, SPSMS, MDN, F-38054 Grenoble, France. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Argonne Natl Lab, Argonne, IL 60439 USA. CSIC, Inst Opt, E-28006 Madrid, Spain. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France. Interfac Reactor Inst, NL-2629 JB Delft, Netherlands. RP Bermejo, FJ (reprint author), CSIC, Inst Estructura Mat, Serrano 123, E-28006 Madrid, Spain. RI Fernandez-Diaz, Maria Teresa/D-7373-2014; Fernandez-Perea, Ricardo/E-9118-2016 OI Fernandez-Perea, Ricardo/0000-0002-4011-2344 NR 30 TC 55 Z9 55 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 DEC 1 PY 1999 VL 60 IS 22 BP 15154 EP 15162 DI 10.1103/PhysRevB.60.15154 PG 9 WC Physics, Condensed Matter SC Physics GA 272BX UT WOS:000084631600032 ER PT J AU Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Britt, HC Chang, J Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Crawford, HJ Cumming, JB Debbe, R Dunlop, JC Eldredge, W Engelage, J Fung, SY Garcia, E Gushue, S Hamagaki, H Hansen, LF Hayano, RS Heintzelman, G Judd, E Kang, J Kim, EJ Kumagai, A Kurita, K Lee, JH Luke, J Miake, Y Mignerey, A Moskowitz, B Moulson, M Muentz, C Nagamiya, S Namboodiri, MN Ogilvie, CA Olness, J Remsberg, LP Sako, H Sangster, TC Seto, R Shea, J Shigaki, K Soltz, R Steadman, SG Stephans, GSF Tannenbaum, MJ Thomas, JH Ueno-Hayashi, S Videbaek, F Wang, F Wu, Y Xiang, H Xu, GH Yagi, K Yao, H Zajc, WA Zhu, F AF Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Britt, HC Chang, J Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Crawford, HJ Cumming, JB Debbe, R Dunlop, JC Eldredge, W Engelage, J Fung, SY Garcia, E Gushue, S Hamagaki, H Hansen, LF Hayano, RS Heintzelman, G Judd, E Kang, J Kim, EJ Kumagai, A Kurita, K Lee, JH Luke, J Miake, Y Mignerey, A Moskowitz, B Moulson, M Muentz, C Nagamiya, S Namboodiri, MN Ogilvie, CA Olness, J Remsberg, LP Sako, H Sangster, TC Seto, R Shea, J Shigaki, K Soltz, R Steadman, SG Stephans, GSF Tannenbaum, MJ Thomas, JH Ueno-Hayashi, S Videbaek, F Wang, F Wu, Y Xiang, H Xu, GH Yagi, K Yao, H Zajc, WA Zhu, F CA E802 Collaboration TI Proton and deuteron production in Au plus Au reactions at 11.6A GeV/c SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEUS-NUCLEUS COLLISIONS; PARTICLE-PRODUCTION; MODEL; FLOW; DISTRIBUTIONS; RESOLUTION; EXPANSION; DETECTOR; SPECTRA AB Proton and deuteron distributions from 11.6A GeV/c Au + Au collisions measured by the E802 Collaboration in experiment E-866 are presented. The invariant yield of protons and deuterons is studied as a function of the transverse mass for different cuts of rapidity and centrality. At low m(t)-m(0) the proton and deuteron invariant spectra deviate from a single exponential shape. The average m(t) as function of centrality and rapidity is used to explore the effect of collective transverse flow in the reaction. The ratio of the deuteron to squared proton yield as a function of transverse momentum, rapidity, and centrality is used to probe the coalescence model of deuteron production. This ratio is constant as a function of rapidity only for the most central cuts and decreases with the centrality for every rapidity cut. The ratio of the differential cross section of the deuteron to the squared differential cross section of the proton, for the most central cut, is not constant as a function of m(t)-m(0). [S0556-2813(99)04911-0]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Riverside, Riverside, CA 94720 USA. Columbia Univ, New York, NY 10027 USA. Nevis Labs, Irvington, NY 10533 USA. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 305, Japan. KEK, High Energy Acelerator Res Org, Tanashi, Tokyo 188, Japan. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Maryland, College Pk, MD 20742 USA. MIT, Cambridge, MA 02139 USA. Univ Tokyo, Sch Sci, Ctr Nucl Study, Tanashi, Tokyo 188, Japan. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Yonsei Univ, Seoul 120749, South Korea. RP Ahle, L (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Mignerey, Alice/D-6623-2011; seto, richard/G-8467-2011; Cumming, James/I-3358-2013; Hayano, Ryugo/F-7889-2012; HAMAGAKI, HIDEKI/G-4899-2014; OI Cumming, James/0000-0001-6930-0958; Hayano, Ryugo/0000-0002-1214-7806; Tannenbaum, Michael/0000-0002-8840-5314; Thomas, James/0000-0002-6256-4536; Ogilvie, Craig/0000-0002-5188-5123 NR 31 TC 97 Z9 99 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 DEC PY 1999 VL 60 IS 6 AR 064901 DI 10.1103/PhysRevC.60.064901 PG 16 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100062 ER PT J AU Ahmad, I Austin, SM Back, BB Betts, RR Calaprice, FP Chan, KC Chishti, A Conner, CM Dunford, RW Fox, JD Freedman, SJ Freer, M Gazes, SB Hallin, AL Happ, T Henderson, D Kaloskamis, NI Kashy, E Kutschera, W Last, J Lister, CJ Liu, M Maier, MR Mercer, DM Mikolas, D Perera, PAA Rhein, MD Roa, DE Schiffer, JP Trainor, TA Wilt, P Winfield, JS Wolanski, M Wolfs, FLH Wuosmaa, AH Young, AR Yurkon, JE AF Ahmad, I Austin, SM Back, BB Betts, RR Calaprice, FP Chan, KC Chishti, A Conner, CM Dunford, RW Fox, JD Freedman, SJ Freer, M Gazes, SB Hallin, AL Happ, T Henderson, D Kaloskamis, NI Kashy, E Kutschera, W Last, J Lister, CJ Liu, M Maier, MR Mercer, DM Mikolas, D Perera, PAA Rhein, MD Roa, DE Schiffer, JP Trainor, TA Wilt, P Winfield, JS Wolanski, M Wolfs, FLH Wuosmaa, AH Young, AR Yurkon, JE TI Positron-electron pairs produced in heavy-ion collisions SO PHYSICAL REVIEW C LA English DT Article ID APEX E(+)E(-) EXPERIMENT; COULOMB-BARRIER; NEUTRAL RESONANCES; BHABHA SCATTERING; ATOM COLLISIONS; TH COLLISIONS; SEARCH; EMISSION; SYSTEMS; LINES AB The production of positron-electron pairs in collisions of (238)U+ (232)Th at 5.95 MeV/nucleon, and of (238)U + (181)Ta at 5.95, 6.1, and 6.3 MeV/nucleon, has been studied with the APEX spectrometer at Argonne National Laboratory. Several analyses have been performed to search for sharp structures in sum-energy spectra for positron-electron pairs. Such features have been reported in previous experiments. No statistically convincing evidence for such behavior is observed in the present data. [S0556-2813(99)06311-6]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Michigan State Univ, NSCL, E Lansing, MI 48824 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Yale Univ, AW Wright Nucl Struct Lab, New Haven, CT 06511 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Birmingham, Sch Phys & Space Res, Birmingham B15 2TT, W Midlands, England. Univ Rochester, Nucl Sci Res Lab, Rochester, NY 14627 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. Gesell Schwerionenforsch mbH, D-64291 Darmstadt, Germany. Univ Washington, Nucl Phys Lab, Seattle, WA 98195 USA. RP Ahmad, I (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RI Hallin, Aksel/H-5881-2011; Freer, Martin/F-9379-2013 NR 39 TC 13 Z9 13 U1 0 U2 1 PU AMER 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 DEC PY 1999 VL 60 IS 6 AR 064601 DI 10.1103/PhysRevC.60.064601 PG 14 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100037 ER PT J AU Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Kumar, BS Lainis, T Lajoie, JG Lewis, RA Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z AF Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Kumar, BS Lainis, T Lajoie, JG Lewis, RA Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z CA E864 Collaboration TI Measurements of neutrons in 11.5A GeV/c Au plus Pb heavy-ion collisions SO PHYSICAL REVIEW C LA English DT Article ID COALESCENCE AB We present measurements from Brookhaven AGS Experiment 864 of neutron invariant multiplicity in 11.5A GeV/c Au+Pb collisions. The measurements span a rapidity range from center of mass to beam rapidity (y(beam) = 3.2) and are presented as a function of event centrality. The results are compared with E864 measurements of proton invariant multiplicity and an average n/p ratio at hadronic freeze-out of 1.19 +/- .08 is determined for the rapidity range y = 1.6 to y = 2.4. We discuss briefly the implications of this ratio within a simple equilibrium model of the collision system. [S0556-2813(99)02112-3]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Columbia Univ, New York, NY 10027 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Massachusetts, Amherst, MA 01003 USA. MIT, Cambridge, MA 02139 USA. Penn State Univ, University Pk, PA 16802 USA. Purdue Univ, W Lafayette, IN 47907 USA. US Mil Acad, W Point, NY 10996 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Wayne State Univ, Detroit, MI 48201 USA. Yale Univ, New Haven, CT 06520 USA. RP Armstrong, TA (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA. NR 23 TC 11 Z9 11 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 DEC PY 1999 VL 60 IS 6 AR 064903 PG 10 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100064 ER PT J AU Bateman, FB Haight, RC Chadwick, MB Sterbenz, SM Grimes, SM Vonach, H AF Bateman, FB Haight, RC Chadwick, MB Sterbenz, SM Grimes, SM Vonach, H TI Light charged-particle production from neutron bombardment of silicon up to 60 MeV: Role of level densities and isospin SO PHYSICAL REVIEW C LA English DT Article ID SI-29 AB Inclusive light charged-particle emission spectra and cross sections from neutron bombardment of silicon were measured at 30 degrees 60 degrees, 90 degrees, and 135 degrees over the neutron energy range from threshold to approximately 60 MeV. Source neutrons, continuous in energy, were provided by the spallation neutron source of the Los Alamos Weapons Neutron Research facility. Comparisons of our alpha-particle data with Hauser-Feshbach calculations, which include multistage emission processes and preequilibrium particle emission, indicate that the majority of alpha particles result from compound nuclear reactions. For proton and deuteron emission, direct and preequilibrium processes contribute significantly to the emission cross section. These data provide rigorous tests for the calculations while helping to guide the selection of input parameters such as nuclear level densities. The effects of assuming partial or complete isospin conservation are shown to be important for these reactions. [S0556-2813(99)02012-9]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ohio Univ, Athens, OH 45701 USA. Inst Radiumforsch & Kernphys, A-1090 Vienna, Austria. RP Bateman, FB (reprint author), NIST Radiat Interact & Dosimetry, 100 Bur Dr,Stop 8460, Gaithersburg, MD 20899 USA. NR 48 TC 33 Z9 33 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 DEC PY 1999 VL 60 IS 6 AR 064609 DI 10.1103/PhysRevC.60.064609 PG 14 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100045 ER PT J AU Bloch, JCR Roberts, CD Schmidt, SM Bender, A Frank, MR AF Bloch, JCR Roberts, CD Schmidt, SM Bender, A Frank, MR TI Nucleon form factors and a nonpointlike diquark SO PHYSICAL REVIEW C LA English DT Article ID QUARK MODEL; BARYON STRUCTURE; COVARIANT; VERTEX; QCD AB Nucleon form factors are calculated on q(2) is an element of [0,3] GeV2 using an ansatz for the nucleon's Faddeev amplitude motivated by quark-diquark solutions of the relativistic Faddeev equation. Only the scalar diquark is retained, and it and the quark are confined. A good description of the data requires a,, nonpointlike diquark correlation with an electromagnetic radius of 0.8 r(pi). The composite, nonpointlike nature of the diquark is crucial. It provides for diquark-breakup terms that are of greater importance than the diquark photon absorption contribution. [S0556-2813(99)51711-1]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Adelaide, Ctr Subatom Struct Matter, Adelaide, SA 5005, Australia. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. RP Bloch, JCR (reprint author), Argonne Natl Lab, Div Phys, Bldg 203, Argonne, IL 60439 USA. NR 26 TC 47 Z9 47 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 062201 PG 5 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100008 ER PT J AU Bloch, JCR Roberts, CD Schmidt, SM AF Bloch, JCR Roberts, CD Schmidt, SM TI Diquark condensation and the quark-quark interaction SO PHYSICAL REVIEW C LA English DT Article ID NJL MODEL; QCD; SUPERCONDUCTIVITY; BOSONIZATION; CONFINEMENT; SPECTRUM; DENSITY; BARYONS AB We employ a bispinor gap equation to study superfluidity at nonzero chemical potential, mu not equal 0, in two- and three-color QCD, exploring the gap's sensitivity to the nature of the quark-quark interaction. The two-color theory, QC(2)D, is an excellent exemplar; the order of truncation of the quark-quark scattering kernel K has no qualitative impact, which allows a straightforward elucidation of the effects of mu when the coupling is strong. in the three-color theory the rainbow-ladder truncation admits diquark bound states, a defect that is eliminated by an improvement of K. The corrected gap equation describes a superfluid phase that is semiquantitatively similar to that obtained using the rainbow truncation. A model study suggests that the width of the superfluid gap and the transition point in QC(2)D provide reliable quantitative estimates of those quantities in QCD. [S0556-2813(99)07112-5]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Bloch, JCR (reprint author), Argonne Natl Lab, Div Phys, Bldg 203, Argonne, IL 60439 USA. NR 31 TC 21 Z9 21 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 DEC PY 1999 VL 60 IS 6 AR 065208 PG 7 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100074 ER PT J AU Brown, CM Milosevich, Z Kaplan, M Vardaci, E DeYoung, P Whitfield, JP Peterson, D Dykstra, C Karol, PJ McMahan, MA AF Brown, CM Milosevich, Z Kaplan, M Vardaci, E DeYoung, P Whitfield, JP Peterson, D Dykstra, C Karol, PJ McMahan, MA TI Light charged particle emission in the matched reactions 280 MeV Ar-40+Al-27 and 670 MeV Mn-55+C-12: Inclusive studies SO PHYSICAL REVIEW C LA English DT Article ID EVAPORATIVE EMISSION; HOT NUCLEI; FUSION; H-1; DEEXCITATION; SPECTRA; MODEL; HE-4 AB In order to test the statistical model's ability to predict the behavior of relatively light mass systems (A approximate to 67) with large angular momenta, two matched heavy ion nuclear reactions were used to produce Ga-67* composite nuclei at an excitation energy of 127 MeV. Light charged particles (protons, deuterons, tritons, and a particles) were used as probes to characterize the composite systems and track the deexcitation processes. From these measurements, energy spectra, cross sections, angular distributions, anisotropy ratios, and particle multiplicities were deduced. Measuring many degrees of freedom provides a stringent test for the statistical models. What is found is that models which did well in predicting the behavior of heavy composite systems (A approximate to 150), are unable to simultaneously reproduce energy spectra, angular distributions, and particle multiplicities for the lighter systems (A approximate to 67), where angular momentum plays a dominant role. This implies that more rigorous models and/or additional physics are needed to understand the behavior of the hot, high-spin nuclear matter in this mass region. [S0556-2813(99)03712-7]. C1 Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA. Hope Coll, Dept Phys, Holland, MI 49423 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Brown, CM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-414, Livermore, CA 94551 USA. NR 27 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 DEC PY 1999 VL 60 IS 6 AR 064612 DI 10.1103/PhysRevC.60.064612 PG 16 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100048 ER PT J AU Caggiano, JA Bazin, D Benenson, W Davids, B Sherrill, BM Steiner, M Yurkon, J Zeller, AF Blank, B AF Caggiano, JA Bazin, D Benenson, W Davids, B Sherrill, BM Steiner, M Yurkon, J Zeller, AF Blank, B TI Spectroscopy of the Li-10 nucleus SO PHYSICAL REVIEW C LA English DT Article ID STATES AB In an attempt to clarify the situation regarding the low-lying structure of Li-10, a spectroscopic measurement of the structure of Li-10 with the Be-9(Be-9,B-8)Li-10 reaction at E(Be-9) =40.1(1) MeV/nucleon was performed using the S800 spectrograph at Michigan State University. The data are fit best with a single p-wave resonance at - S-n = 0.500(60) MeV with a width of Gamma = 400(60) keV. No higher lying states were observed and there is no evidence of a state at similar to 250 keV in the data. An excess strength at threshold was observed, but cannot be definitively attributed to a state. [S0556-2813(99)05211-5]. C1 Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. CEN Bordeaux Gradignan, F-33175 Gradignan, France. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Sherrill, Bradley/B-4098-2009; Sherrill, Bradley/B-3378-2011 NR 24 TC 30 Z9 30 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 064322 DI 10.1103/PhysRevC.60.064322 PG 5 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100035 ER PT J AU Chen, JW Savage, MJ AF Chen, JW Savage, MJ TI np -> d gamma for big-bang nucleosynthesis SO PHYSICAL REVIEW C LA English DT Article AB The cross section for np-->d gamma is calculated at energies relevant to big-bang nucleosynthesis using the recently developed effective field theory that describes the two-nucleon sector. The E1 amplitude is computed up to (NLO)-L-3 and depends only upon nucleon-nucleon phase shift data. In contrast, the M1 contribution is computed up to next-to-leading order, and the four-nucleon-one-magnetic-photon counterterm that enters is determined by the cross section for cold neutron capture. The uncertainty in the calculation for nucleon energies up to E similar to 1 MeV is estimated to be less than or similar to 4%. [S0556-2813(99)02612-6]. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Chen, JW (reprint author), Univ Washington, Dept Phys, Seattle, WA 98195 USA. OI Chen, Jiunn-Wei/0000-0002-8650-9371 NR 17 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 065205 DI 10.1103/PhysRevC.60.065205 PG 6 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100071 ER PT J AU Cullen, DM King, SL Reed, AT Sampson, JA Walker, PM Wheldon, C Xu, F Dracoulis, GD Lee, IY Macchiavelli, AO MacLeod, RW Wilson, AN Barton, C AF Cullen, DM King, SL Reed, AT Sampson, JA Walker, PM Wheldon, C Xu, F Dracoulis, GD Lee, IY Macchiavelli, AO MacLeod, RW Wilson, AN Barton, C TI High-K multiquasiparticle configurations and limiting moments of inertia in W-178 SO PHYSICAL REVIEW C LA English DT Article ID QUASI-PARTICLE STATES; ROTATING NUCLEI; ISOMERS; HF-175 AB Three new high-K multiquasiparticle intrinsic states, K-pi = (29(+)), K-pi = 30(+), and K-pi =(34(+)), have been assigned in W-178. The configurations of these states are based on ten, eight, and ten, unpaired nucleons, respectively, and they represent the highest-seniority intrinsic K states observed no date. The gamma-ray intensity branching ratios and associated \g(K)-g(R)\ values have been used to contribute to the specifications of the underlying single-particle configurations of the states. Configuration-constrained potential energy surface calculations indicate that the nucleus retains stably deformed axially symmetric shapes. This evidence, coupled with the experimental gamma-ray decay rates, suggests that K remains a good quantum number in these highest-seniority intrinsic state configurations. The aligned angular moments of the K-pi = (29(+)), K-pi = 30(+), and K-pi = (34(+)) bands are observed to be lower than those of the other eight quasiparticle, K-pi = 25(+) and K-pi = 28(-) bands in W-178. These differences are interpreted as the effects of reduced pairing due to blocking by the constituent particles. While the dynamic moments of inertia are similar, they remain substantially less than those of a classical rigid rotor, apparently saturating at a value of about 56 (h) over bar(2) MeV-1. [S0556-2813(99)03611-0]. C1 Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Australian Natl Univ, RSPhysSE, Dept Nucl Phys, Canberra, ACT 0200, Australia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Yale Univ, Wright Nucl Struct Lab, New Haven, CT 06511 USA. RP Cullen, DM (reprint author), Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. RI Dracoulis, George/A-8123-2008; Wheldon, Carl/F-9203-2013; Sampson, Janet/G-4960-2013; Xu, Furong/K-4178-2013 NR 26 TC 22 Z9 22 U1 1 U2 4 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 DEC PY 1999 VL 60 IS 6 AR 064301 DI 10.1103/PhysRevC.60.064301 PG 11 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100014 ER PT J AU Kahana, DE Kahana, SH AF Kahana, DE Kahana, SH TI H dibaryon and the hard core SO PHYSICAL REVIEW C LA English DT Article ID COLLISIONS; MODEL AB The H dibaryon, a single, maximally symmetric bag containing two up, two down, and two strange quarks, has long been sought after in a variety of experiments. Its creation has been attempted with K-'s or protons as projectiles and most recently in relativistic heavy ion induced reactions. We concentrate on the latter, but our conclusions are more generally applicable. The two baryons coalescing to form the single dibaryon, likely hn in the case of heavy ions, must penetrate the short range repulsive barrier which is expected to exist between them. We find that this barrier can profoundly affect the probability of producing the H state, should it actually exist. [S0556-2813(99)03912-6]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kahana, DE (reprint author), 31 Pembrook Dr, Stony Brook, NY 11790 USA. OI Kahana, David Ewan/0000-0003-1266-9089 NR 25 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 065206 DI 10.1103/PhysRevC.60.065206 PG 5 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100072 ER PT J AU Lane, GJ Dracoulis, GD Byrne, AP Poletti, AR McGoram, TR AF Lane, GJ Dracoulis, GD Byrne, AP Poletti, AR McGoram, TR TI Population of high-spin states in U-234 by an incomplete-fusion reaction SO PHYSICAL REVIEW C LA English DT Article AB Excited states in U-234 have been populated using the incomplete-fusion reaction Th-232(Be-9,alpha 3n) at 52 MeV. The emitted gamma rays were observed using the CAESAR array, while the ct particles were detected with an array of 14 plastic scintillator detectors of phoswich type. This reaction can populate U-234 at higher spin than the conventional Th-232(alpha,2n) reaction because the ''He-5'' fragment from breakup of the beam can be viewed as initiating a Th-232(He-5,3n) reaction. Similar reactions could provide a Valuable alternative technique for the study of relatively heavy, neutron-rich isotopes. In the present work, states in the ground-state band of U-234 were observed up to J(pi)=18(+) and previous tentative observations of (9(-)) and (11(-)) states in the octupole band were confirmed. A new state at 1366 keV, which is possibly the 8(+) member of the gamma band, has also been identified. [S0556-2813(99)02911-8]. C1 Australian Natl Univ, RS Phys SE, Dept Nucl Phys, Canberra, ACT 0200, Australia. Australian Natl Univ, The Faculties, Dept Phys, Canberra, ACT 0200, Australia. Univ Auckland, Dept Phys, Auckland, New Zealand. RP Lane, GJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd,MS-88, Berkeley, CA 94720 USA. RI Dracoulis, George/A-8123-2008; Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 14 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 067301 DI 10.1103/PhysRevC.60.067301 PG 3 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100082 ER PT J AU Nicoli, MP Haas, F Freeman, RM Aissaoui, N Beck, C Elanique, A Nouicer, R Morsad, A Szilner, S Basrak, Z Brandan, ME Satchler, GR AF Nicoli, MP Haas, F Freeman, RM Aissaoui, N Beck, C Elanique, A Nouicer, R Morsad, A Szilner, S Basrak, Z Brandan, ME Satchler, GR TI Elastic scattering of O-16+O-16 at energies E/A between 5 and 8 MeV SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION SCATTERING; NUCLEAR-MATTER; O-16; SYSTEM; POTENTIALS; BEHAVIOR; FUSION AB The elastic scattering of O-16+O-16 has been measured at nine energies between E-lab = 75 and 124 MeV. The data cover up to 100 degrees in the c.m. and can be described in terms of phenomenological and folding model potentials which reproduce the main features observed. In agreement with studies at higher energies in this and similar systems, refractive effects are present in the angular distributions at all energies. In particular, the passage of Airy minima through 90 degrees at E-c.m. = 40, 47.5, and 62 MeV explains the deep minima observed in the excitation function. The real part of the optical potential is found to vary very little with energy over the studied interval, but the imaginary part shows a rapid change in its shape at incident energy about 90 MeV. Nonetheless, the energy dependence of the volume integral of the real and imaginary parts is in agreement with dispersion relation predictions. [S0556-2813(99)05611-3]. C1 Inst Rech Subatom, IN2P3, CNRS, UMR 7500, F-67037 Strasbourg 2, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Univ Hassan II, Fac Sci Ben Msik, Casablanca, Morocco. Rudjer Boskovic Inst, Zagreb, Croatia. Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Nicoli, MP (reprint author), Inst Rech Subatom, IN2P3, CNRS, UMR 7500, Boite Postale 28, F-67037 Strasbourg 2, France. RI Brandan, Maria-Ester/K-9014-2012 OI Brandan, Maria-Ester/0000-0002-1165-3440 NR 42 TC 67 Z9 67 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 DEC PY 1999 VL 60 IS 6 AR 064608 DI 10.1103/PhysRevC.60.064608 PG 10 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100044 ER PT J AU Sakhaee, M Zhu, SJ Hamilton, JH Ramayya, AV Hwang, JK Zhang, XQ Yang, LM Zhu, LY Gan, CY Jones, EF Gore, PM Ginter, TN Babu, BRS Ma, WC Konnicki, J Beyer, CJ Long, GL Deng, JK Li, K Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Asztalos, S Lee, IY Macchiavelli, AO Chu, SY Giegorich, KE Mohar, MF Stoyer, MA Lougheed, RW Lee, IY Moody, KJ Wild, JF Prussin, SG Ter-Akopian, GM Daniel, AV Oganessian, YT AF Sakhaee, M Zhu, SJ Hamilton, JH Ramayya, AV Hwang, JK Zhang, XQ Yang, LM Zhu, LY Gan, CY Jones, EF Gore, PM Ginter, TN Babu, BRS Ma, WC Konnicki, J Beyer, CJ Long, GL Deng, JK Li, K Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Asztalos, S Lee, IY Macchiavelli, AO Chu, SY Giegorich, KE Mohar, MF Stoyer, MA Lougheed, RW Lee, IY Moody, KJ Wild, JF Prussin, SG Ter-Akopian, GM Daniel, AV Oganessian, YT TI Identification of levels in neutron-rich Ce-145 and Ce-147 nuclei SO PHYSICAL REVIEW C LA English DT Article ID OCTUPOLE CORRELATIONS; SPONTANEOUS FISSION; BARIUM ISOTOPES; BAND STRUCTURES; SPECTROSCOPY; DEFORMATION; FRAGMENTS; XE-139; CF-252; RAYS AB High-spin structures in the neutron-rich nuclei Ce-145 and Ce-147 produced in the spontaneous fission of Cf-252 have been investigated by prompt gamma-ray spectroscopy. A collective band structure in Ce-145 is identified. Several sidebands along with the new high-spin states in Ce-147 are also identified. Particle-plus-rotor model calculations indicate that the yrast bands in Ce-145 and Ce-147 most probably originate from coupling of the nu i(13/2) orbital to the ground states of Ce-144 and Ce-146. The ground state configurations of Ce-145,Ce-147 are (nu h(9/2) + nu f(7/2)) and nu h(9/2), respectively. [S0556-2813(99)05312-1]. C1 Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Idaho Natl Environm Engn Lab, Idaho Falls, ID 83415 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Joint Inst Nucl Res, Flerov Lab Nucl React, Dubna 141980, Russia. RP Sakhaee, M (reprint author), Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. RI Long, Gui Lu/B-1170-2008; Long, Gui Lu/B-8988-2014 OI Long, Gui Lu/0000-0002-9023-1579 NR 20 TC 10 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 067303 DI 10.1103/PhysRevC.60.067303 PG 3 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100084 ER PT J AU Smith, AG Simpson, GS Billowes, J Dagnall, PJ Durell, JL Freeman, SJ Leddy, M Phillips, WR Roach, AA Smith, JF Jungclaus, A Lieb, KP Teich, C Gall, BJP Hoellinger, F Schulz, N Ahmad, I Greene, JP Algora, A AF Smith, AG Simpson, GS Billowes, J Dagnall, PJ Durell, JL Freeman, SJ Leddy, M Phillips, WR Roach, AA Smith, JF Jungclaus, A Lieb, KP Teich, C Gall, BJP Hoellinger, F Schulz, N Ahmad, I Greene, JP Algora, A TI Correlated spins of complementary fragment pairs in the spontaneous fission of Cf-252 SO PHYSICAL REVIEW C LA English DT Article ID ANGULAR-MOMENTUM; GAMMA-RAYS AB A study of the gamma-ray decay of low-lying excited states in fragments produced in the spontaneous fission of Cf-252 has revealed a significant correlation between the angles of emission of the 2(1)(+) --> 0(1)(+) transitions of complementary fragment pairs. Calculations of the amount of dealignment that is needed to reproduce the measured a(2) values, and a comparison with the results of previous fragment-gamma angular distribution measurements, suggests that at scission there may be significant population of m not equal 0 substates associated with the projection of the fragment spin vector on the fission axis. Fragments from the spontaneous fission of Cm-248 emit 2(1)(+) --> 0(1)(+) gamma rays that show markedly reduced interfragment correlations, suggesting that either a larger role is played by the relative angular momentum of the fragments, or that the dealignment introduced by the neutron emission and statistical gamma decay to the 2(1)(+) state is larger in Cm-248 than Cf-252 fission. [S0556-2813(99)03412-3]. C1 Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. Univ Gottingen, Inst Phys 2, D-37073 Gottingen, Germany. IN2P3, CNRS, Inst Rech Subatom, F-67037 Strasbourg, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Argonne Natl Lab, Argonne, IL 60439 USA. Lab Nazl Legnaro, I-35020 Legnaro, PD, Italy. RP Smith, AG (reprint author), Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. RI Freeman, Sean/B-1280-2010; Algora, Alejandro/E-2960-2015 OI Freeman, Sean/0000-0001-9773-4921; Algora, Alejandro/0000-0002-5199-1794 NR 17 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 064611 PG 4 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100047 ER PT J AU Srivastava, BK Albergo, S Bieser, F Brady, FP Caccia, Z Cebra, DA Chacon, AD Chance, JL Choi, Y Costa, S Danielewicz, P Elliott, JB Gilkes, ML Hauger, JA Hirsch, AS Hjort, EL Insolia, A Justice, M Keane, D Kintner, JC Lindenstruth, V Lisa, MA Matis, HS McMahan, M McParland, C Muller, WFJ Olson, DL Partlan, MD Porile, NT Potenza, R Rai, G Rasmussen, J Ritter, HG Romanski, J Romero, JL Russo, GV Sann, H Scharenberg, RP Scott, A Shao, Y Symons, TJM Tincknell, M Tuve, C Wang, S Warren, P Wieman, HH Wienold, T Wolf, K AF Srivastava, BK Albergo, S Bieser, F Brady, FP Caccia, Z Cebra, DA Chacon, AD Chance, JL Choi, Y Costa, S Danielewicz, P Elliott, JB Gilkes, ML Hauger, JA Hirsch, AS Hjort, EL Insolia, A Justice, M Keane, D Kintner, JC Lindenstruth, V Lisa, MA Matis, HS McMahan, M McParland, C Muller, WFJ Olson, DL Partlan, MD Porile, NT Potenza, R Rai, G Rasmussen, J Ritter, HG Romanski, J Romero, JL Russo, GV Sann, H Scharenberg, RP Scott, A Shao, Y Symons, TJM Tincknell, M Tuve, C Wang, S Warren, P Wieman, HH Wienold, T Wolf, K TI Comparison of the 1A (GeVAu)-Au-197+C interaction with first-stage transport codes SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; QUANTUM MOLECULAR-DYNAMICS; INTRANUCLEAR CASCADE CALCULATION; HE-3+ AG-NAT; AU-197 REACTIONS; NUCLEAR-MATTER; TPC DETECTOR; GEV GOLD; MULTIFRAGMENTATION; ENERGY AB The properties of the remnant resulting from the emission of prompt particles in the interaction of 1A GeV Au-197+C interactions have been compared with intranuclear cascade and Boltzmann-Uehling-Uhlenback transport calculations. The number of first-stage particles and the energy spectra of first-stage protons are also compared. Both models can fit the general but not the detailed features of the data. [S0556-2813(99)03312-9]. C1 Purdue Univ, W Lafayette, IN 47907 USA. Univ Catania, I-95129 Catania, Italy. Ist Nazl Fis Nucl, Sez Catania, I-95129 Catania, Italy. Univ Calif Davis, Davis, CA 95616 USA. GSI Darmstadt, D-64220 Darmstadt, Germany. Kent State Univ, Kent, OH 44242 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Texas A&M Univ, College Stn, TX 77843 USA. Michigan State Univ, Dept Phys, E Lansing, MI 48824 USA. Michigan State Univ, NSCL, E Lansing, MI 48824 USA. RP Purdue Univ, W Lafayette, IN 47907 USA. RI TUVE', Cristina/P-3933-2015; Insolia, Antonio/M-3447-2015 OI TUVE', Cristina/0000-0003-0739-3153; Insolia, Antonio/0000-0002-9040-1566 NR 37 TC 8 Z9 8 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 064606 DI 10.1103/PhysRevC.60.064606 PG 7 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100042 ER PT J AU Veal, KD Brune, CR Geist, WH Karwowski, HJ Ludwig, EJ Bartosz, EE Cathers, PD Drummer, TL Kemper, KW Eiro, AM Santos, FD Kozlowska, B Maier, HJ Thompson, IJ AF Veal, KD Brune, CR Geist, WH Karwowski, HJ Ludwig, EJ Bartosz, EE Cathers, PD Drummer, TL Kemper, KW Eiro, AM Santos, FD Kozlowska, B Maier, HJ Thompson, IJ TI Determination of the asymptotic D- to S-state ratio for Li-6 via ((6)(Li)over-right-arrow,d) transfer reactions SO PHYSICAL REVIEW C LA English DT Article ID MONTE-CARLO CALCULATIONS; ELASTIC-SCATTERING; POLARIZED LI-6; LIGHT-NUCLEI; (D)OVER-RIGHT-ARROW,T REACTIONS; MODEL; POTENTIALS; DEUTERON; TRITON; HE-3 AB Measurements of cross section, vector analyzing power A(y), and tensor analyzing powers A(zz) and A(xz) over the angular range 10 degrees less than or equal to theta(lab) less than or equal to 40 degrees have been performed at E(Li-6) = 34 MeV for the Ni-58((6)<(Li)over right arrow>, d)Zn-62 and Ca-40((6)<(Li)over right arrow>, d)Ti-44 reactions leading to the ground state and first excited state of both residual nuclei. The reactions an described by distorted-wave Born approximation calculations, assuming a direct alpha-particle transfer mechanism. The asymptotic D/S state ratio eta for the d + alpha relative wave function in Li-6 is determined. In this one-step analysis, the best fit to the tensor observables leads to a value of eta = +0.0003 +/- 0.0009. This value is in disagreement with most of the previous theoretical and empirical determinations of eta. An investigation of two-step reaction mechanisms is performed, allowing the J(pi) = 3(+), 2(+), and 1(+) states in Li-6 to contribute to the transfer reaction channel. Reasonable agreement is achieved with the cross section and vector analyzing power data for several possible two-step amplitudes. It is found that the fitted magnitude of eta increases with increasing two-step amplitude, giving eta = -0.0030 +/- 0.0022 for unit amplitude, therefore not changing significantly from our one-step result. [S0556-2813(99)00812-2]. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Triangle Univ Nucl Lab, Durham, NC 27788 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Lisbon, Dept Fis, P-1699 Lisbon, Portugal. Univ Lisbon, Ctr Fis Nucl, P-1699 Lisbon, Portugal. Univ Silesia, Inst Phys, Katowice, Poland. Univ Munich, D-8046 Garching, Germany. Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. RP Veal, KD (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 57 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 064003 PG 14 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100012 ER PT J AU Vincent, SM Regan, PH Mohammadi, S Blumenthal, D Carpenter, M Davids, CN Gelletly, W Ghugre, SS Henderson, DJ Janssens, RVF Hjorth-Jensen, M Kharraja, B Lister, CJ Pearson, CJ Seweryniak, D Schwartz, J Simpson, J Warner, DD AF Vincent, SM Regan, PH Mohammadi, S Blumenthal, D Carpenter, M Davids, CN Gelletly, W Ghugre, SS Henderson, DJ Janssens, RVF Hjorth-Jensen, M Kharraja, B Lister, CJ Pearson, CJ Seweryniak, D Schwartz, J Simpson, J Warner, DD TI Near yrast study of the fpg shell nuclei Ni-58, Cu-61, and Zn-61 SO PHYSICAL REVIEW C LA English DT Article ID HIGH-SPIN STATES; GAMMA-RAY SPECTROSCOPY; ESCAPE SUPPRESSED SPECTROMETER; ROTATIONAL BAND; EXCITED-STATES; BETA-DECAY; COINCIDENCE; PERFORMANCE; DETECTORS; STABILITY AB The medium spin, near yrast states of the fpg shell nuclei Ni-58, Cu-61, and Zn-61 have been studied following the fusion evaporation of a Mg-24 beam and a Ca-40 target. Discrete transitions were unambiguously identified using the AYEBALL gamma-ray array in conjunction with the Argonne fragment mass analyzer and a split anode ionization chamber. The decay schemes of Ni-58(28), Cu-61(29), and Zn-61(30) have been extended with the results of gamma-gamma coincidences and directional correlation from oriented state measurements used to determine the level excitation energies, spins, and parities of a number of near yrast states. The decay schemes deduced are compared with previous work and interpreted in terms of shell model calculations, with a restricted basis of the f(5/2), p(3/2), p(1/2) orbitals outside a Ni-58(28) core, and either the g(9/2) orbital with a closed core, or f(7/2) excitations from the core. [S0556-2813(99)01112-7]. C1 Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. IUCDAEF, Calcutta Ctr, Calcutta 700064, W Bengal, India. Univ Oslo, Dept Phys, N-0316 Oslo, Norway. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Yale Univ, AW Wright Nucl Struct Lab, New Haven, CT 06511 USA. SERC, Daresbury Lab, CLRC, Warrington WA4 4AD, Cheshire, England. Payam E Nour Univ, Dept Phys, Fariman 9391433, Iran. RP Vincent, SM (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RI Hjorth-Jensen, Morten/B-1417-2008; Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 61 TC 23 Z9 26 U1 0 U2 1 PU AMER 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 DEC PY 1999 VL 60 IS 6 AR 064308 DI 10.1103/PhysRevC.60.064308 PG 18 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100021 ER PT J AU Wang, FQ AF Wang, FQ TI Residual correlation in two-proton interferometry from Lambda-proton strong interactions SO PHYSICAL REVIEW C LA English DT Article AB We investigate the residual effect of Lambda p strong interactions in pp correlations with one proton from Lambda decays. It is found that the residual correlation is about 10% of the Lambda p correlation strength, and has a broad distribution centered around q approximate to 40 MeV/c. The residual correlation cannot explain the observed structure on the tail of the recently measured pp correlation function in central Pb+Pb collisions by NA49 at the Super Proton Synchrotron. [S0556-2813(99)05512-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Wang, FQ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD DEC PY 1999 VL 60 IS 6 AR 067901 PG 3 WC Physics, Nuclear SC Physics GA 266RF UT WOS:000084313100091 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M 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 Blusk, S Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C 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, D Cerri, A 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 da Costa, JG Costanzo, D 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 Gadomski, S 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 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 Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R 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, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K 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 IV Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loreti, M Lucchesi, D Lukens, P Lusin, S 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, C Miao, T Miller, R Miller, JS 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 Parri, A Partos, D Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D 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 Truitt, S 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 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 Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, A AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M 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 Blusk, S Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C 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, D Cerri, A 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 da Costa, JG Costanzo, D 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 Gadomski, S 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 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 Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R 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, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K 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 IV Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loreti, M Lucchesi, D Lukens, P Lusin, S 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, C Miao, T Miller, R Miller, JS 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 Parri, A Partos, D Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D 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 Truitt, S 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 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 Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, A CA CDF Collaboration TI Measurement of the B-0(B)over-bar-(0) oscillation frequency using l(-)D *(+) pairs and lepton flavor tags SO PHYSICAL REVIEW D LA English DT Article ID = 1.8 TEV; PHOTON CROSS-SECTION; SEMILEPTONIC B-DECAY; P(P)OVER-BAR COLLISIONS; PARTICLE PHYSICS; LIFETIME; DETECTOR; CDF AB The oscillation frequency Delta m(d) of B-0(B) over bar(0) mixing is measured using the partially reconstructed semileptonic decay (B) over bar(0) --> l(-) <(nu)over bar>D*(+) X. The data sample was collected with the CDF detector at the Fermilab Tevatron collider during 1992-1995 by triggering on the existence of two lepton candidates in an event, and corresponds to about 110 pb(-1) of (p) over bar p collisions at root s = 1.8 TeV. We estimate the proper decay time of the (B) over bar(0) meson from the measured decay length and reconstructed momentum of the l(-) D*(+) system. The charge of the lepton in the final state identifies the flavor of the (B) over bar(0) meson at its decay. The second lepton in the event is used to infer the flavor of the (B) over bar(0) meson at production. We measure the oscillation frequency to be Delta m(d)=0.516 +/- 0.099(-0.035)(+0.029) ps(-1), where the first uncertainty is statistical and the second is systematic. [S0556-2821(99)04623-8]. 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 Cantabria, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Inst Nucl Res, 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, Dept Chem, Suwon 440746, South Korea. KEK, High Energy Accelerator Res Org, 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 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. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, 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 Affolder, T (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Prokoshin, Fedor/E-2795-2012; 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; Introzzi, Gianluca/K-2497-2015; vilar, rocio/D-7454-2014 OI Prokoshin, Fedor/0000-0001-6389-5399; 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; Introzzi, Gianluca/0000-0002-1314-2580; NR 41 TC 15 Z9 15 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 1 PY 1999 VL 60 IS 11 AR 112004 DI 10.1103/PhysRevD.60.112004 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100011 ER PT J AU Barger, V Kao, C AF Barger, V Kao, C TI Trilepton signature of minimal supergravity at the upgraded Fermilab Tevatron SO PHYSICAL REVIEW D LA English DT Article ID NEUTRALINO DARK-MATTER; LARGE TAN-BETA; SUPERSYMMETRIC STANDARD MODEL; W+/-Z PRODUCTION; GRAND UNIFICATION; RELIC DENSITY; B->S-GAMMA CONSTRAINTS; PBARP COLLIDERS; LEPTONIC DECAYS; EVENT RATES AB The prospects for detecting trilepton events (l = e or mu) from chargino-neutralino (chi(1)(+/-)chi(2)(0)) associated production are investigated for the upgraded Fermilab Tevatron Collider in the context of the minimal supergravity model (MSUGRA). In some regions of parameter space, chi(1)(+/-) and chi(2)(0) decay dominantly into final states with tau leptons and the contributions from tau-leptonic decays enhance the trilepton signal substantially when soft cuts on lepton transverse momenta are used. Additional sources of the MSUGRA trilepton signal and dominant irreducible backgrounds are discussed. The dilepton (l(+)l(-)) invariant mass distribution near the end point is considered as a test of MSUGRA mass relations. Discovery contours for p (p) over bar 3l + X at 2 TeV with an integrated luminosity of 2-30 fb(-1) an presented in the MSUGRA parameter space of (m(0), m(1/2)) for several choices of tan beta. [S0556-2821(99)07223-9]. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Barger, V (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 90 TC 74 Z9 74 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 DEC 1 PY 1999 VL 60 IS 11 AR 115015 DI 10.1103/PhysRevD.60.115015 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100087 ER PT J AU Bern, Z Del Duca, V Kilgore, WB Schmidt, CR AF Bern, Z Del Duca, V Kilgore, WB Schmidt, CR TI Infrared behavior of one-loop QCD amplitudes at next-to-next-to-leading order SO PHYSICAL REVIEW D LA English DT Article ID JET CROSS-SECTIONS; GAUGE-THEORY AMPLITUDES; MULTI-GLUON SCATTERING; YANG-MILLS THEORY; E+E-ANNIHILATION; HELICITY AMPLITUDES; PERTURBATIVE QCD; RADIATIVE-CORRECTIONS; HADRON COLLIDERS; PARTON PROCESSES AB We present universal factorization formulas describing the behavior of one-loop QCD amplitudes as external momenta become either soft or collinear. Our results are valid to all orders in the dimensional regularization parameter, epsilon. Terms through O(epsilon(2)) can contribute in infrared divergent phase space integrals associated with next-to-next-to-leading order jet cross sections. [S0556-2821(99)07417-2]. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Ist Nazl Fis Nucl, Sez Torino, I-10125 Turin, Italy. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RI del duca, vittorio/F-6992-2012 NR 95 TC 145 Z9 145 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 DEC 1 PY 1999 VL 60 IS 11 AR 116001 DI 10.1103/PhysRevD.60.116001 PG 25 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100091 ER PT J AU Bloch, JCR Mizerny, VA Prozorkevich, AV Roberts, CD Schmidt, SM Smolyansky, SA Vinnik, DV AF Bloch, JCR Mizerny, VA Prozorkevich, AV Roberts, CD Schmidt, SM Smolyansky, SA Vinnik, DV TI Pair creation: Back reactions and damping SO PHYSICAL REVIEW D LA English DT Article ID STRONG ELECTRIC-FIELD; HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; FLUX-TUBE; DECAY AB We solve the quantum Vlasov equation for fermions and bosons, incorporating spontaneous pair creation in the presence of back reactions and collisions. Pair creation is initiated by an external impulse field and the source term is non-Markovian. A simultaneous solution of Maxwell's equation in the presence of feedback yields an internal current and electric field that exhibit plasma oscillations with a period tau(pl). Allowing for collisions, these oscillations are damped on a time scale tau(r) determined by the collision frequency. Plasma oscillations cannot affect the early stages of the formation of a quark-gluon plasma unless tau(r)much greater than tau(pl) and tau(pl) similar to 1/Lambda(QCD)similar to 1 fm/c. [S0556-2821(99)06123-8]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Saratov State Univ, Dept Phys, Saratov, Russia. RP Bloch, JCR (reprint author), Argonne Natl Lab, Div Phys, Bldg 203, Argonne, IL 60439 USA. NR 26 TC 73 Z9 74 U1 0 U2 4 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 DEC 1 PY 1999 VL 60 IS 11 AR 116011 DI 10.1103/PhysRevD.60.116011 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100101 ER PT J AU Bloch, JCR Kalinovsky, YL Roberts, CD Schmidt, SM AF Bloch, JCR Kalinovsky, YL Roberts, CD Schmidt, SM TI Describing a(1) and b(1) decays SO PHYSICAL REVIEW D LA English DT Article ID DYSON-SCHWINGER EQUATIONS; PROPAGATORS; PHYSICS; QUARK; MESON AB Two-body pion-radiating and weak decays of light axial-vector mesons and the rho are studied as an application of the Dyson-Schwinger equations. Models based on the rainbow-ladder truncation are capable of providing a good description, and yield the correct sign and magnitude of the a(1) --> rho pi and b(1) --> omega pi D/S ratios, with no additional mechanism necessary. [S0556-2821(99)50321-4]. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Joint Inst Nucl Res, Lab Comp Tech & Automat, Dubna 141980, Russia. RP Bloch, JCR (reprint author), Argonne Natl Lab, Div Phys, Bldg 203, Argonne, IL 60439 USA. NR 26 TC 35 Z9 35 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 1 PY 1999 VL 60 IS 11 AR 111502 DI 10.1103/PhysRevD.60.111502 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100006 ER PT J AU Blum, T Soni, A Wingate, M AF Blum, T Soni, A Wingate, M TI Calculation of the strange quark mass using domain wall fermions SO PHYSICAL REVIEW D LA English DT Article ID LATTICE QCD; WILSON FERMIONS; MATRIX-ELEMENTS; CHIRAL FERMIONS; 4-FERMION OPERATORS; PERTURBATION-THEORY; DECAY CONSTANTS; GAUGE-THEORIES; BREAKING; OVERLAP AB We present a first calculation of the strange quark mass using domain wall fermions. This paper contains an overview of the domain wall discretization and a pedagogical presentation of the perturbative calculation necessary for computing the mass renormalization. We combine the latter with numerical simulations to estimate the strange quark mass. Our final result in the quenched approximation is 95(26) MeV in the <(MS)over bar> scheme at a scale of 2 GeV. We find that domain wail fermions have a small perturbative mass renormalization, similar to Wilson quarks, and exhibit good scaling behavior. [S0556-2821(99)01723-3]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. NR 54 TC 25 Z9 25 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 DEC 1 PY 1999 VL 60 IS 11 AR 114507 DI 10.1103/PhysRevD.60.114507 PG 22 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100068 ER PT J AU Brodsky, SJ Merino, C Pelaez, JR AF Brodsky, SJ Merino, C Pelaez, JR TI Measuring the QCD Gell-Mann-Low Psi function SO PHYSICAL REVIEW D LA English DT Article ID FREE GAUGE THEORIES; RENORMALIZATION-SCHEME; QUANTUM CHROMODYNAMICS; EFFECTIVE CHARGES; DECAY AB We present a general method for extracting the Gell-Mann-Low logarithmic derivative of an effective charge of an observable directly from data as a mean for empirically verifying the universal terms of the QCD beta function. Our method avoids the biases implicit in fitting to QCD-motivated forms as well as the interpolation errors introduced by constructing derivatives from discrete data. We also derive relations between moments of effective charges as new tests of perturbative QCD. [S0556-2821(99)00221-0]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Santiago de Compostela, Dept Fis Particulas, Santiago De Compostela 15706, Spain. Univ Complutense Madrid, Dept Fis Teor, E-28040 Madrid, Spain. RP Brodsky, SJ (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM pelaez@eucmax.sim.ucm.es RI Pelaez, Jose/K-9767-2014 OI Pelaez, Jose/0000-0003-0737-4681 NR 18 TC 0 Z9 0 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 1 PY 1999 VL 60 IS 11 AR 114007 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100026 ER PT J AU Campbell, JM Ellis, RK AF Campbell, JM Ellis, RK TI Update on vector boson pair production at hadron colliders SO PHYSICAL REVIEW D LA English DT Article ID ALPHA-S CALCULATION; W+/-Z PRODUCTION; HIGGS-BOSON; GAUGE-INVARIANCE; RADIATIVE-CORRECTIONS; PARTON DISTRIBUTIONS; UNSTABLE PARTICLES; QCD CORRECTIONS; W-W+; COLLISIONS AB We present numerical results (including full one-loop QCD corrections) for the processes and pp --> W+ W-, W+/- Z/gamma* and Z/gamma* Z/gamma* followed by the decay of the massive vector bosons into leptons. In addition to their intrinsic importance as tests of the standard model, these processes are also backgrounds to conjectured non-standard model processes. Because of the small cross sections at the Fermilab Tevatron, full experimental control of these backgrounds will be hard to achieve. This accentuates the need for up-to-date theoretical information. A comparison is made with earlier work and cross section results are presented for pp collisions at root s = 2 TeV and pp collisions at root s = 14TeV. Practical examples of the use of our calculations are presented. [S0556-2821(99)01323-5]. C1 Fermilab, Theory Dept, Batavia, IL 60510 USA. RP Campbell, JM (reprint author), Fermilab, Theory Dept, POB 500, Batavia, IL 60510 USA. NR 39 TC 581 Z9 581 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 DEC 1 PY 1999 VL 60 IS 11 AR 113006 DI 10.1103/PhysRevD.60.113006 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100017 ER PT J AU Capstick, S Page, PR AF Capstick, S Page, PR TI Constructing hybrid baryons with flux tubes SO PHYSICAL REVIEW D LA English DT Article ID QUARK-MODEL; MESONS; QCD; HADRONS; P11 AB Hybrid baryon states are described in quark potential models as having explicit excitation of the gluon degrees of freedom. Such states are described in a model motivated by the strong coupling limit of Hamiltonian lattice gauge theory, where three flux tubes meeting at a junction play the role of the glue. The adiabatic approximation for the quark motion is used, and the flux tubes and junction are modeled by beads which are attracted to each other and the quarks by a linear potential, and vibrate in various string modes. Quantum numbers and estimates of the energies of the lightest hybrid baryons are provided. [S0556-2821(99)50221-X]. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Florida State Univ, Supercomp Computat Res Inst, Tallahassee, FL 32306 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Capstick, S (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RI Page, Philip/L-1885-2015 OI Page, Philip/0000-0002-2201-6703 NR 28 TC 40 Z9 41 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 DEC 1 PY 1999 VL 60 IS 11 AR 111501 DI 10.1103/PhysRevD.60.111501 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100005 ER PT J AU Dixon, L Kunszt, Z Signer, A AF Dixon, L Kunszt, Z Signer, A TI Vector boson pair production in hadronic collisions at O(alpha(s)): Lepton correlations and anomalous couplings SO PHYSICAL REVIEW D LA English DT Article ID ALPHA-S CALCULATION; W+/-Z PRODUCTION; WW-GAMMA COUPLINGS; TO-LEADING ORDER; QCD CORRECTIONS; WZ PRODUCTION; P(P)OVER-BAR COLLISIONS; PARTON DISTRIBUTIONS; GLOBAL ANALYSIS; ROOT-S=1.8 TEV AB We present cross sections for the production of electroweak vector boson pairs, WW, WZ, and ZZ, in p (p) over bar and pp collisions, at next-to-leading order in alpha(s). We treat the leptonic decays of the bosons in the narrow-width approximation, but retain all spin information via decay angle correlations. We also include the effects of WWZ and WW gamma anomalous couplings. [S0556-2821(99)06421-8]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. ETH Zurich, Inst Theoret Phys, Zurich, Switzerland. Univ Durham, Dept Phys, Durham DH1 3LE, England. RP Dixon, L (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Kunszt, Zoltan/G-3420-2013 NR 45 TC 108 Z9 109 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 DEC 1 PY 1999 VL 60 IS 11 AR 114037 DI 10.1103/PhysRevD.60.114037 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100056 ER PT J AU Fujii, H Kharzeev, D AF Fujii, H Kharzeev, D TI Long-range forces of QCD SO PHYSICAL REVIEW D LA English DT Article ID NUCLEAR-BOUND QUARKONIUM; HADRONIC TRANSITIONS; LOW-ENERGY; SUPPRESSION; COLLISIONS; ANOMALIES; PARTICLE; GLUONIUM; STATES; VAN AB We consider the scattering of two color dipoles (e.g., heavy quarkonium states) at low energy-a QCD :analogue of van der Waals interaction. Even though the couplings: of the dipoles to the gluon field can be described in perturbation theory, which leads to a potential:proportional to (N-c(2)-1)/R-7, large distances R the interaction becomes totally nonperturbative. Low-energy QCD theorems are used to evaluate the leading long-distance contribution similar to(N-f(2)-1)/(11N(c)-2N(f))(2) R(-5/2)exp(-2 mu R) (mu is the Goldstone boson mass), which is shown to arise from the correlated two-boson exchange. The sum rule which relates the overall strength of the interaction to the energy density of the QCD vacuum is derived. Surprisingly, we find that when the size of the dipoles shrinks to zero (the heavy quark limit in the case of quarkonia), the nonperturbative part of the interaction vanishes more slowly than the perturbative part as a: consequence of the scale anomaly. As an: application, we evaluate elastic pi J/psi, and pi J/psi --> pi psi' cross sections. [S0556-2821(99)01123-6]. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Fujii, H (reprint author), Univ Tokyo, Inst Phys, Tokyo 1538902, Japan. NR 56 TC 30 Z9 30 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 DEC 1 PY 1999 VL 60 IS 11 AR 114039 DI 10.1103/PhysRevD.60.114039 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100058 ER PT J AU Isgur, N AF Isgur, N TI Flux tube zero-point motion, hadronic charge radii, and hybrid meson production cross sections SO PHYSICAL REVIEW D LA English DT Article ID HEAVY MESONS; FORM-FACTORS; QUARK-MODEL; B-DECAYS; PHOTOPRODUCTION; FACTORIZATION; BREAKING; QCD AB Flux tube zero-point motion produces quark displacements transverse to the flux tube which make significant Contributions to hadronic charge radii. In heavy quark systems, these contributions can be related by Bjorken's sum rule to the rates for semileptonic decay to hybrid mesons. This connection can be generalized to other leptoproduction processes, where transverse contributions to elastic form factor slopes are related to the cross sections for the production of the associated hybrid starts. I identify the flux tube overlap integral responsible for these effects as the strong QCD analogue of the Sudakov form factor of perturbative QCD. [S0556-2821(99)05121-8]. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Isgur, N (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 36 TC 23 Z9 23 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 DEC 1 PY 1999 VL 60 IS 11 AR 114016 DI 10.1103/PhysRevD.60.114016 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100035 ER PT J AU Lee, W Sharpe, SR AF Lee, W Sharpe, SR TI Partial flavor symmetry restoration for chiral staggered fermions SO PHYSICAL REVIEW D LA English DT Article ID PERTURBATIVE CORRECTIONS; LATTICE QCD; WILSON FERMIONS; OPERATORS; BILINEARS; MESONS AB We study the leading discretization errors for staggered fermions by first constructing the continuum effective Lagrangian, including terms of O(a(2)), and then constructing the corresponding effective chiral Lagrangian. The terms of O(a(2)) in the continuum effective Lagrangian completely break the SU(4) flavor symmetry down to the discrete subgroup respected by the lattice theory. We find, however, that the O(a(2)) terms in the potential of the chiral Lagrangian maintain an SO(4) subgroup of SU(4). It follows that the leading discretization errors in the pion masses are SO(4) symmetric, implying three degeneracies within the seven lattice irreducible representations. These predictions hold also for perturbatively improved versions of the action. These degeneracies are observed, to a surprising degree of accuracy, in existing data. We argue that the SO(4) symmetry does not extend to the masses and interactions of other hadrons (vector mesons, baryons, etc.) or to higher order in a(2). We show how it is possible that, for physical quark masses of O(a(2)), the new SO(4) symmetry can be spontaneously broken, leading to a staggered analogue of the Aoki phase of Wilson fermions. This does not, however, appear to happen for presently studied versions of the staggered action. [S0556-2821(99)06923-4]. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Tsukuba, Ctr Computat Phys, Tsukuba, Ibaraki 3058577, Japan. RP Los Alamos Natl Lab, Mail Stop B 285, Los Alamos, NM 87545 USA. EM wlee@lanl.gov; sharpe@phys.washington.edu NR 26 TC 137 Z9 137 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 DEC 1 PY 1999 VL 60 IS 11 AR 114503 DI 10.1103/PhysRevD.60.114503 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100064 ER PT J AU Ligeti, Z Wise, MB AF Ligeti, Z Wise, MB TI (B)over-bar -> K* gamma from D -> K*(l)over-bar-v SO PHYSICAL REVIEW D LA English DT Article ID RARE-B-DECAYS; UB-VERTICAL-BAR; FORM-FACTORS; V-UB; MASS-SPECTRUM; MESON DECAYS; B->K-ASTERISK-GAMMA; HEAVY; LATTICE; TRANSITIONS AB The (B) over bar-->K*gamma branching fraction is predicted using heavy quark spin symmetry at large recoil to relate the tensor and (axial-)vector form factors, using heavy quark flavor symmetry to relate the B decay form factors to the measured D-->K*(l) over bar nu form factors, and extrapolating the semileptonic B decay form factors to large recoil assuming nearest pole dominance. This prediction agrees with data surprisingly well, and we comment on its implications for the extraction of \V-ub\ from (B) over bar-->rho l<(nu)over bar>. [S0556-2821(99)07023-X]. C1 Fermi Natl Accelerator Lab, Theory Grp, Batavia, IL 60510 USA. CALTECH, Pasadena, CA 91125 USA. RP Ligeti, Z (reprint author), Fermi Natl Accelerator Lab, Theory Grp, POB 500, Batavia, IL 60510 USA. NR 34 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 DEC 1 PY 1999 VL 60 IS 11 AR 117506 DI 10.1103/PhysRevD.60.117506 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100107 ER PT J AU Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JP Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Patton, S Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Spencer, MB Wolf, A Zoeller, MM AF Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JP Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Patton, S Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Spencer, MB Wolf, A Zoeller, MM CA CLEO Collaboration TI Study of 3-prong hadronic tau decays with charged kaons SO PHYSICAL REVIEW D LA English DT Article ID PHYSICS; LEPTONS; MESONS AB Using a sample of 4.7 fb(-1) integrated luminosity accumulated with the CLEO-II detector at the Cornell Electron Storage Ring (CESR), we have measured the ratios of the branching fractions B(tau(-) --> K- h(+) pi(-) nu(tau))/B(tau(-) --> h(-) h(+) h(-) v(tau)) = (5.16+/-0.20+/-0.50) X 10(-2), B(tau(-) --> K- h(+) pi(-) pi(0) nu(tau))/B(tau(-) --> h(-) h(+) h(-) pi(0) nu(tau)) = (2.54+/-0.44+/-0.39) X 10(-2), B(tau(-) --> K- K+ pi(-) nu(tau))/B(tau(-) --> h(-) h(+) h(-) nu(tau)) = (1.52+/-0.14+/-0.29) X 10(-2), and the upper limit B(tau(-) --> K- K+ pi(-) pi(0) nu(tau))/B(tau(-) --> h(-) h(+) h(-) pi(0) nu(tau)) < 0.0154 at 95% C.L. Coupled with additional experimental information, we use our results to extract information on the structure of three-prong tau decays to charged kaons. [S0556-2821(99)03319-6]. C1 Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Montreal, PQ, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Texas, Austin, TX 78712 USA. RP Richichi, SJ (reprint author), Univ Oklahoma, Norman, OK 73019 USA. RI Briere, Roy/N-7819-2014 OI Briere, Roy/0000-0001-5229-1039 NR 23 TC 20 Z9 20 U1 1 U2 3 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 DEC 1 PY 1999 VL 60 IS 11 AR 112002 DI 10.1103/PhysRevD.60.112002 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100009 ER PT J AU Rizzo, TG AF Rizzo, TG TI Tests of low scale gravity via gauge boson pair production in gamma gamma collisions SO PHYSICAL REVIEW D LA English DT Article ID LINEAR COLLIDERS; DIMENSIONS; BEAMS; TEV; GAMMA-GAMMA->W+W; MILLIMETER; COUPLINGS; MOMENTS; FUSION AB Arkani-Hamed, Dimopoulos, and Dvali have recently proposed that gravity may become strong at energies near 1 TeV thus removing the hierarchy problem. This scenario can be tested in several ways at present and future colliders. In this paper we examine the exchange of towers of Kaluza-Klein gravitons and their influence on the production of pairs of massive gauge bosons in gamma gamma collisions. These tower exchanges are shown to lead to a new dimension-eight operator that can significantly alter the standard model expectations for these processes. The role of polarization for both the initial state photons and the final-state gauge bosons in improving sensitivity to graviton exchange is emphasized. We find the discovery reach for graviton tower exchange in the gamma gamma --> W+W- channel to be significantly greater than for any other process so far examined. [S0556-2821(99)04321-0]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Rizzo, TG (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 73 TC 34 Z9 34 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 1 PY 1999 VL 60 IS 11 AR 115010 DI 10.1103/PhysRevD.60.115010 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100082 ER PT J AU Wong, CY AF Wong, CY TI Soft gluon emission process in the color-octet model for heavy quarkonium production SO PHYSICAL REVIEW D LA English DT Article ID FIXED TARGET ENERGIES; PI-N INTERACTIONS; J-PSI; J/PSI HADROPRODUCTION; JET FRAGMENTATION; COLLISIONS; PHOTOPRODUCTION; ANNIHILATION; DECAY AB The color-octet model has been used successfully to analyze many problems in heavy quarkonium production. We examine some of the conceptual and practical problems of the soft gluon emission process in the color-octet model. We use a potential model to describe the initial and final states in the soft gluon emission process, as the emission occurs at a late stage, after the production of the heavy quark pair. It is found in this model that the soft gluon M1 transition S-1(0)(8)-->S-3(1)(1) dominates over the E1 transition P-3(J)(8)-->S-3(1)(1) for J/psi and psi' production. Such a dominance may help resolve the questions of isotropic polarization and color-octet matrix element universality in the color-octet model. [S0556-2821(99)03721-2]. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Wong, CY (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 37 TC 19 Z9 19 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 DEC 1 PY 1999 VL 60 IS 11 AR 114025 DI 10.1103/PhysRevD.60.114025 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 263RB UT WOS:000084138100044 ER PT J AU Hochberg, D Molina-Paris, C Perez-Mercader, J Visser, M AF Hochberg, D Molina-Paris, C Perez-Mercader, J Visser, M TI Effective action for stochastic partial differential equations SO PHYSICAL REVIEW E LA English DT Article ID RENORMALIZATION-GROUP ANALYSIS; FIELD-THEORY RENORMALIZATION; PARISI-ZHANG EQUATION; STATISTICAL DYNAMICS; BURGERS-EQUATION; ZETA-FUNCTIONS; FLUCTUATIONS; TURBULENCE; UNIVERSE; SYMMETRY AB Stochastic partial differential equations (SPDEs) are the basic tool for modeling systems where noise is important. SPDEs are used for models of turbulence, pattern formation, and the structural development of the universe itself. It is reasonably well known that certain SPDEs can be manipulated to be equivalent to (nonquantum) field theories that nevertheless exhibit deep and important relationships with quantum field theory. In this paper we systematically extend these ideas: We set up a functional integral formalism and demonstrate how to extract all the one-loop physics for an arbitrary SPDE subject to arbitrary Gaussian noise. It is extremely important to realize that Gaussian noise does nor imply that the field variables undergo Gaussian fluctuations, and that these nonquantum field theories are fully interacting. The limitation to one loop is not as serious as might be supposed: Experience with quantum field theories (QFTs) has taught us that one-loop physics is often quite adequate to give a good description of the salient issues. The limitation to one loop does, however, offer marked technical advantages: Because at one loop almost any field theory can be rendered finite using zeta function technology, we can sidestep the complications inherent in the Martin-Sig,aia-Rose formalism (the SPDE analog of the Becchi-Rouet-Stora-Tyutin formalism used in QFT) and instead focus attention on a minimalist approach that uses only the physical fields (this "direct approach" is the SPDE analog of canonical quantization using physical fields). After setting up the general formalism for the characteristic functional (partition function), we show how to define the effective action to all loops, and then focus on the one-loop effective action and its specialization to constant fields: the effective potential. The physical interpretation of the effective action and effective potential for SPDEs is addressed and we show that key features carry over from QFT to the case of SPDEs. An important result is that the amplitude of the two-point function governing the noise acts as the loop-counting parameter and is the analog of Planck's constant h in this SPDE context. We derive a general expression for the one-loop effective potential of an arbitrary SPDE subject to translation-invariant;Gaussian noise, and compare this with the one-loop potential for QFT. [S1063-651X(99)12011-7]. C1 Lab Astrofis Espacial & Fis Fundamental, E-28080 Madrid, Spain. INTA, Ctr Astrobiol, Madrid 28850, Spain. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. RP Hochberg, D (reprint author), Lab Astrofis Espacial & Fis Fundamental, Apartado 50727, E-28080 Madrid, Spain. NR 57 TC 35 Z9 36 U1 0 U2 12 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 DEC PY 1999 VL 60 IS 6 BP 6343 EP 6360 DI 10.1103/PhysRevE.60.6343 PN A PG 18 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NM UT WOS:000084600400022 PM 11970549 ER PT J AU Tsironis, GP Bishop, AR Savin, AV Zolotaryuk, AV AF Tsironis, GP Bishop, AR Savin, AV Zolotaryuk, AV TI Dependence of thermal conductivity on discrete breathers in lattices SO PHYSICAL REVIEW E LA English DT Article ID ENERGY-TRANSPORT; HEAT-CONDUCTION; OSCILLATORS; DYNAMICS; CHAINS AB We study the properties of heat conduction in chains of coupled particles subjected to different anharmonic on-site potentials. Particular emphasis is placed on the role of breathers in saturation of the thermal conductivity for chains with hard anharmonicity; When the chain particles are subject to on-site potentials with soft anharmonicity, we find a characteristic temperature, below which the conductivity decreases but while above which it increases. [S1063-651X(99)05912-7]. C1 Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Crete, Dept Phys, Rethimnon, Greece. Fdn Res & Technol, FORTH, Iraklion 71003, Greece. RP Los Alamos Natl Lab, Div Theory, MS-B258, Los Alamos, NM 87545 USA. RI Tsironis, George/C-2683-2011 NR 13 TC 65 Z9 67 U1 1 U2 1 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 DEC PY 1999 VL 60 IS 6 BP 6610 EP 6613 DI 10.1103/PhysRevE.60.6610 PN A PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NM UT WOS:000084600400054 PM 11970581 ER PT J AU Janaki, TM Rangarajan, G Habib, S Ryne, RD AF Janaki, TM Rangarajan, G Habib, S Ryne, RD TI Computation of the Lyapunov spectrum for continuous-time dynamical systems and discrete maps SO PHYSICAL REVIEW E LA English DT Article ID EXPONENTS AB In this paper, we describe in detail a method of computing Lyapunov exponents for a continuous-time dynamical system and extend the method to discrete maps. Using this method, a partial Lyapunov spectrum can be computed using fewer equations as compared to the computation of the full spectrum, there is no difficulty in evaluating degenerate Lyapunov spectra, the equations are straightforward to generalize to higher dimensions, and the minimal set of dynamical variables is used. Explicit proofs and other details not given in previous work are included here. [S1063-651X(99)07212-8]. C1 Indian Inst Sci, Dept Math, Bangalore 560012, Karnataka, India. Univ Calif Los Alamos Natl Lab, Theoret Div T8, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, LANSCE 1, LANSCE Div, Los Alamos, NM 87545 USA. RP Janaki, TM (reprint author), Indian Inst Sci, Dept Math, Bangalore 560012, Karnataka, India. NR 12 TC 19 Z9 19 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD DEC PY 1999 VL 60 IS 6 BP 6614 EP 6626 DI 10.1103/PhysRevE.60.6614 PN A PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NM UT WOS:000084600400055 PM 11970582 ER PT J AU Sides, SW Grest, GS Lacasse, MD AF Sides, SW Grest, GS Lacasse, MD TI Capillary waves at liquid-vapor interfaces: A molecular dynamics simulation SO PHYSICAL REVIEW E LA English DT Article ID X-RAY; POLYMER/POLYMER INTERFACES; SURFACE; MIXTURES; FILMS AB Evidence for capillary waves at a liquid-vapor interface are presented from extensive molecular dynamics simulations of a system containing up to 1.24 million Lennard-Jones particles. Careful measurements show that the total interfacial width depends logarithmically on L-parallel to the length of the simulation cell parallel to the interface, as predicted theoretically. The strength of the divergence of the interfacial width on L-parallel to depends inversely on the surface tension gamma. This allows us to measure gamma two ways since gamma can also be obtained from the difference in the pressure parallel and perpendicular to the interface. These two independent measures of gamma agree provided that the interfacial order parameter profile is fit to an error function and not a hyperbolic tangent, as often assumed. We explore why these two common fitting functions give different results for gamma. [S1063-651X(99)02512-X]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Exxon Res & Engn Co, Corp Res Sci Labs, Annandale, NJ 08801 USA. RP Sides, SW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 26 TC 94 Z9 96 U1 0 U2 14 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 DEC PY 1999 VL 60 IS 6 BP 6708 EP 6713 DI 10.1103/PhysRevE.60.6708 PN A PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NM UT WOS:000084600400063 PM 11970590 ER PT J AU Mach, P Pindak, R Levelut, AM Barois, P Nguyen, HT Baltes, H Hird, M Toyne, K Seed, A Goodby, JW Huang, CC Furenlid, L AF Mach, P Pindak, R Levelut, AM Barois, P Nguyen, HT Baltes, H Hird, M Toyne, K Seed, A Goodby, JW Huang, CC Furenlid, L TI Structures of chiral smectic-C mesophases revealed by polarization-analyzed resonant x-ray scattering SO PHYSICAL REVIEW E LA English DT Article ID ANTIFERROELECTRIC LIQUID-CRYSTALS; SMC-ALPHA-STAR; DEVILS STAIRCASE; FORBIDDEN REFLECTIONS; PHASE-TRANSITION; TILT ANGLE; BIREFRINGENCE; MHPOBC; FILMS; MODEL AB We report polarization-analyzed, resonant x-ray diffraction at the sulfur K edge performed upon freestanding liquid-crystal films. Our studies of the thiobenzoate liquid-crystal enantiomer 100TBBB1M7 yield the polarization states of resonant satellite peaks arising from characteristic superlattices in the chiral smectic-C (SmC*) variant phases, including the antiferroelectric SmCA*, ferrielectric SmCFI1* and SmCFI2*, as well as SmCalpha*. The observed polarizations agree with the clock model of chiral smectic-C variants, and rule out other proposals made to date for these structures. Data from the 100TBBB1M7 racemate also support the clock model. Our resonant diffraction results from a thiophene liquid-crystal compound reveal the same superlattice periodicities seen in corresponding antiferroelectric and ferrielectric phases of 100TBBB1M7. [S1063-651X(99)12411-5]. C1 Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Ctr Univ Paris Sud, Lab Phys Solide, F-91405 Orsay, France. Univ Bordeaux 1, Ctr Rech Paul Pascal, CNRS, F-33600 Pessac, France. Univ Hull, Sch Chem, Kingston Upon Hull HU6 7RX, N Humberside, England. Brookhaven Natl Lab, NLSL, Upton, NY 11973 USA. RP Bell Labs, Lucent Technol, 600 Mt Ave, Murray Hill, NJ 07974 USA. NR 34 TC 137 Z9 138 U1 2 U2 11 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 DEC PY 1999 VL 60 IS 6 BP 6793 EP 6802 DI 10.1103/PhysRevE.60.6793 PN A PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NM UT WOS:000084600400072 PM 11970599 ER PT J AU Moore, JD Cui, ST Cochran, HD Cummings, PT AF Moore, JD Cui, ST Cochran, HD Cummings, PT TI Transient rheology of a polyethylene melt under shear SO PHYSICAL REVIEW E LA English DT Article ID CONCENTRATED POLYMER SYSTEMS; MOLECULAR-DYNAMICS SIMULATION; COX-MERZ RULE; LINEAR POLYETHYLENE; POLYMETHYLENE MELTS; ENTANGLED POLYMERS; SELF-DIFFUSION; ROUSE MODEL; BEHAVIOR; MOTION AB Using nonequilibrium molecular dynamics simulation, we have studied the response of a C-100 model polymer melt to a step change from equilibrium to a constant, high shear rate flow. The transient shear stress of the model polymer melt exhibits pronounced overshoot at the strain value predicted by the reptation model, in striking similarity to melts of longer, entangled polymer governed by reptation motion. Ar the maximum of shear stress overshoot, the molecular orientational order and the alignment angle are found to be midway between those characteristic of Newtonian flow and full alignment with the flow. The Doi-Edwards theory is found to be applicable but only by taking into account the shear-rate-dependence of the terminal relaxation time. We further analyze the molecular origins of such behavior in short polymer chains by decomposing the total stress into the contributions from various molecular interactions. [S1063-651X(99)08911-4]. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. RP Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RI Moore, Jonathan/B-8201-2009; Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 37 TC 18 Z9 18 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 DEC PY 1999 VL 60 IS 6 BP 6956 EP 6959 DI 10.1103/PhysRevE.60.6956 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NQ UT WOS:000084600700008 PM 11970633 ER PT J AU Wallace, DC AF Wallace, DC TI Application of liquid dynamics theory the the glass transition SO PHYSICAL REVIEW E LA English DT Article ID SUPERCOOLED LIQUIDS; MOLECULAR-DYNAMICS; ARGON; MODEL AB In monatomic liquid dynamics theory, the system moves among a large number of intersecting nearly harmonic valleys in the many-particle potential energy surface, The same potential surface underlies the motion of atoms in the supercooled liquid. As temperature is decreased below the melting temperature, the motion among the potential valleys will begin to freeze out, and the system will pass out of equilibrium. It is therefore necessary to develop a nonequilibrium theory, based on the Hamiltonian motion. The motion is separated into two distinct parts, and idealized as follows: (a) the vibrational motion within a single valley is assumed to be purely harmonic, and remaining in equilibrium; and (b) the transit motion, which carries the system from one valley to another, is assumed to be, instantaneous, and energy and momentum conserving. This idealized system is capable of exhibiting a,glass transition behavior. An elementary model, incorporating the idealized motion, is the independent atom model, originally developed to treat self diffusion in monatomic liquids. For supercooled liquids, in the independent atom model, the vanishing of self diffusion at a finite temperature implies the same property for the transit probability. The vanishing of the transit probability at a finite temperature supports the view that transits are not merely thermally activated, but are controlled by phase-space correlations. For supercooled liquid sodium, the transit probability has Vogel-Tamann-Fulcher temperature dependence. The independent atom model is shown to be capable of exhibiting all the essential glass transition properties, including rate dependence of the glass transition temperature, and both exponential and nonexponential relaxation. [S1063-651X(99)01412-9]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Wallace, DC (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 29 TC 5 Z9 5 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD DEC PY 1999 VL 60 IS 6 BP 7049 EP 7056 DI 10.1103/PhysRevE.60.7049 PN B PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NQ UT WOS:000084600700019 PM 11970644 ER PT J AU Jeon, D Holmes, JA Danilov, VV Galambos, JD Olsen, DK AF Jeon, D Holmes, JA Danilov, VV Galambos, JD Olsen, DK TI Effects of resonances on halo formation in high-intensity storage rings SO PHYSICAL REVIEW E LA English DT Article ID CHARGED-PARTICLE BEAM; SPACE-CHARGE; ENVELOPE AB Numerical calculations for the Spallation Neutron Source accumulator ring indicate that lattice resonances excited by the space-charge potential can increase a mismatch significantly by deforming the beam distribution in phase space. Hence increased mismatch leads to enhanced envelops oscillations that are driving the 2:1 parametric resonance leading to halo formation, even for initially matched beams. We have observed this behavior for the 2 v(x) - 2 v(y) = 0 resonance and for the 4 v(y) = 23 resonance. This mechanism for halo formation peculiar to rings through resonance driven mismatch is very sensitive to the tunes, which emphasizes the importance of a careful choice of operating point in tune space. [S1063-651X(99)10012-6]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Jeon, D (reprint author), Oak Ridge Natl Lab, SNS Bldg MS-8218,104 Union Valley Rd, Oak Ridge, TN 37831 USA. RI Jeon, Dong-O/S-2137-2016 OI Jeon, Dong-O/0000-0001-6482-5878 NR 18 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 DEC PY 1999 VL 60 IS 6 BP 7479 EP 7483 DI 10.1103/PhysRevE.60.7479 PN B PG 5 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NQ UT WOS:000084600700071 PM 11970696 ER PT J AU Maniadis, P Tsironis, GP Bishop, AR Zolotaryuk, AV AF Maniadis, P Tsironis, GP Bishop, AR Zolotaryuk, AV TI Soliton-breather reaction pathways SO PHYSICAL REVIEW E LA English DT Article ID HYDROGEN-BONDED CHAINS; SINE-GORDON SOLITONS; NONLINEAR LATTICES; INTEGRABLE SYSTEMS; DISCRETE; LOCALIZATION; MODELS AB We use a collective coordinate approach to investigate corpuscular properties of breathers in nonlinear lattice systems. We calculate the breather internal energy and inertial mass and use them to analyze the reaction pathways of breathers with kinks that are preformed in the lattice. We find that there is an effective kink-breather intraction potential that, under some circumstances, is attractive and has a double well shape. Furthermore, we find that in some cases the internal energy of a moving breather can be relased during the reaction with the kink and subsequently transformed to kink translational energy. These breather properties seem to be model independent. [S1063-651X(99)05411-2]. C1 Univ Crete, Dept Phys, Rethimnon, Greece. Fdn Res & Technol Hellas, FORTH, Iraklion 71003, Crete, Greece. Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Bogolyubov Inst Theoret Phys, UA-252143 Kiev, Ukraine. RP Univ Crete, Dept Phys, Rethimnon, Greece. RI Tsironis, George/C-2683-2011; Maniadis, Panagiotis/A-7861-2012 NR 29 TC 13 Z9 14 U1 0 U2 2 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 DEC PY 1999 VL 60 IS 6 BP 7618 EP 7621 DI 10.1103/PhysRevE.60.7618 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 271NQ UT WOS:000084600700100 PM 11970725 ER PT J AU Etter, T Noyes, HP AF Etter, T Noyes, HP TI Process, system, causality, and quantum mechanics: A psychoanalysis of animal faith SO PHYSICS ESSAYS LA English DT Article DE core laws of quantum mechanics; foundations of quantum mechanics; measurement theory; laboratory object; link theory; EPR paradox; Markov processes; time reversal; future boundary conditions; negative probabilities AB We shall argue in this paper that a central piece of modern physics does not really belong to physics at all but to elementary probability theory. Given a joint probability distribution J on a set of random variables containing x and y, define a link between x and y to be the condition x = y an J. Define the state D of a link x = y as the joint probability distribution matrix on x and y without the link. The two core laws of quantum mechanics are the Born probability rule and the unitary dynamical law, whose best known form is Schrodinger's equation. Von Neumann formulated these two laws in the language of Hilbert space as prob(P) = trace(PD) and D'T = TD, respectively, where P is a projection, D and D' are (von Neumann) density matrices, and T is a unitary transformation. We'll see that if we regard link stares as density matrices, the algebraic forms of these two core laws are completely general theorems about links. When we extend probability theory by allowing cases to count negatively, we find that the Hilbert space framework of quantum mechanics proper emerges from the assumption that all D's are symmetrical in rows and columns. On the other hand, Markovian systems emerge when we assume that one of every linked variable pair has a uniform probability distribution. By representing quantum and Markovian structure in this way, we see clearly both how they differ and also how they can coexist in natural harmony with each other, as they must in quantum measurement, which we will examine. Looking beyond quantum mechanics, we see how both structures have their special places in a much larger continuum of formal systems that we have yet to look for in nature. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94039 USA. RP Etter, T (reprint author), 112 Blackburn Ave, Menlo Park, CA 94025 USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU PHYSICS ESSAYS PUBLICATION PI HULL PA C/O ALFT INC, 189 DEVEAULT ST, UNIT NO. 7, HULL, PQ J8Z1S7, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD DEC PY 1999 VL 12 IS 4 BP 733 EP 765 PG 33 WC Physics, Multidisciplinary SC Physics GA 397PD UT WOS:000166703300013 ER PT J AU Montgomery, HE AF Montgomery, HE CA CDF Collaboration D0 Collaboration TI Recent results from the Tevatron Collider SO PHYSICS OF ATOMIC NUCLEI LA English DT Article; Proceedings Paper CT Conference on Fundamental Interactions of Elementary Particles CY NOV 16-20, 1998 CL RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS, MOSCOW, RUSSIA SP Russian Acad Sci, Inst Theoret & Exptl Phys, Dept Nucl Phys HO RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS ID P(P)OVER-BAR COLLISIONS; ROOT-S=1.8 TEV; CROSS-SECTION AB In as much as space permits, we discuss some examples of interesting results recently obtained by the CDF and D0 experiments at the Tevatron Collider. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Montgomery, HE (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD DEC PY 1999 VL 62 IS 12 BP 1955 EP 1962 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 282DD UT WOS:000085200500001 ER PT J AU Chung, SU AF Chung, SU CA BNL-E852 Collaboration TI New results on exotic mesons from BNL-E852 SO PHYSICS OF ATOMIC NUCLEI LA English DT Article; Proceedings Paper CT Conference on Fundamental Interactions of Elementary Particles CY NOV 16-20, 1998 CL RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS, MOSCOW, RUSSIA SP Russian Acad Sci, Inst Theoret & Exptl Phys, Dept Nucl Phys HO RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS ID 18 GEV/C; SYSTEM AB We have so far found evidence for two exotic mesons with the quantum numbers I(G)J(PC) = 1(-)1(-+) at masses 1.4 and 1.6 GeV. They are seen in the decay channels pi eta, pi rho, and pi eta' with varying degrees of strength. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Chung, SU (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 24 TC 0 Z9 0 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD DEC PY 1999 VL 62 IS 12 BP 1971 EP 1975 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 282DD UT WOS:000085200500003 ER PT J AU Alde, D Binon, F Blick, AM Boutemeur, M Bricman, C Dolgopolov, AV Donskov, SV Gouanere, M Inyakin, AV Khaustov, GV Knapp, EA Kolosov, VN Kondashov, AA Lednev, AA Lishin, VA Mikhailov, YV Peigneux, JP Polovnikov, SA Polyakov, VA Poulet, M Sadovsky, SA Samoylenko, VD Shagin, PM Singovsky, AV Sobol, AE Stroot, JP Sugonyaev, VP Zvyagin, AV AF Alde, D Binon, F Blick, AM Boutemeur, M Bricman, C Dolgopolov, AV Donskov, SV Gouanere, M Inyakin, AV Khaustov, GV Knapp, EA Kolosov, VN Kondashov, AA Lednev, AA Lishin, VA Mikhailov, YV Peigneux, JP Polovnikov, SA Polyakov, VA Poulet, M Sadovsky, SA Samoylenko, VD Shagin, PM Singovsky, AV Sobol, AE Stroot, JP Sugonyaev, VP Zvyagin, AV CA GAMS Collaboration TI New results of the GAMS collaboration on meson spectroscopy SO PHYSICS OF ATOMIC NUCLEI LA English DT Article; Proceedings Paper CT Conference on Fundamental Interactions of Elementary Particles CY NOV 16-20, 1998 CL RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS, MOSCOW, RUSSIA SP Russian Acad Sci, Inst Theoret & Exptl Phys, Dept Nucl Phys HO RUSSIAN ACAD SCI, INST THEORET & EXPTL PHYS, DEPT NUCL PHYS ID GEV/C AB New results on meson spectroscopy that were obtained by the GAMS collaboration over the years 1997 and 1998 are presented. A partial-wave analysis of the pi(0)pi(0) system formed in charge-exchange pi(-)p interaction at a momentum of 100 GeV/c has been performed. The eta eta system produced in the reaction pi(-)p --> eta eta n at a momentum of 38 GeV/c has been studied. The results of a partial-wave analysis of the pi(0)pi(0) system formed in central proton-proton collisions at a momentum of 450 GeV/c have been discussed. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Inst Interuniv Sci Nucl, Brussels, Belgium. Protvino High Energy Phys Inst, Protvino 142284, Moscow, Russia. Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. CERN, CH-1211 Geneva 23, Switzerland. RP Alde, D (reprint author), Univ Calif Los Alamos Natl Lab, POB 1163, Los Alamos, NM 87545 USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD DEC PY 1999 VL 62 IS 12 BP 1993 EP 1998 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 282DD UT WOS:000085200500006 ER PT J AU He, GW Doolen, GD Chen, SY AF He, GW Doolen, GD Chen, SY TI Calculations of longitudinal and transverse velocity structure functions using a vortex model of isotropic turbulence SO PHYSICS OF FLUIDS LA English DT Article ID INTENSE VORTICITY; INTERMITTENCY; INCREMENTS; FILAMENTS; HIERARCHY; LAWS AB The longitudinal structure function (LSF) and the transverse structure function (TSF) in isotropic turbulence are calculated using a vortex model. The vortex model is composed of the Rankine and Burgers vortices which have the exponential distributions in the vortex Reynolds number and vortex radii. This model exhibits a power law in the inertial range and satisfies the minimal condition of isotropy that the second-order exponent of the LSF in the inertial range is equal to that of the TSF. Also observed are differences between longitudinal and transverse structure functions caused by intermittency. These differences are related to their scaling differences which have been previously observed in experiments and numerical simulations. (C) 1999 American Institute of Physics. [S1070-6631(99)02512-X]. 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. Chinese Acad Sci, Inst Mech, Lab Nonlinear Mech Continuous Media, Beijing 100080, Peoples R China. RP He, GW (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010 NR 29 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD DEC PY 1999 VL 11 IS 12 BP 3743 EP 3748 DI 10.1063/1.870236 PG 6 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 252HK UT WOS:000083495900015 ER PT J AU Barnes, DC AF Barnes, DC TI Uniform-density, spherical electron focus SO PHYSICS OF PLASMAS LA English DT Article ID PENNING TRAP; BRILLOUIN LIMIT; PLASMA AB An equilibrium electron distribution is exhibited which forms a uniform electron density focus within a spherical system. Such a focus may be used to form a spherical, harmonic well for ion focusing as previously discussed. A self-consistent density and space-charge potential are calculated and the optimum focus radius is determined. Nonideal effects on electron and ion motion in the resulting electrostatic well are briefly discussed and strategies for their minimization are derived. (C) 1999 American Institute of Physics. [S1070-664X(99)00912-X]. C1 Univ Calif Los Alamos Natl Lab, Appl theoret & Computat Div, Los Alamos, NM 87545 USA. RP Barnes, DC (reprint author), Univ Calif Los Alamos Natl Lab, Appl theoret & Computat Div, B-259, Los Alamos, NM 87545 USA. NR 11 TC 8 Z9 8 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 DEC PY 1999 VL 6 IS 12 BP 4472 EP 4478 DI 10.1063/1.873734 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900010 ER PT J AU Brunner, S Valeo, E Krommes, JA AF Brunner, S Valeo, E Krommes, JA TI Collisional delta-f scheme with evolving background for transport time scale simulations SO PHYSICS OF PLASMAS LA English DT Article ID GYROKINETIC PARTICLE SIMULATION; ELECTRON DISTRIBUTIONS; HEAT-TRANSPORT; PLASMAS AB The delta f approach is extended for simulating the transport time-scale evolution of near-Maxwellian distributions in collisional plasmas. This involves simultaneously advancing weighted marker particles for representing the intrinsically kinetic component delta f, and fluid equations for the parameters of the shifted Maxwellian background f(SM). The issue of increasing numerical noise in a collisional delta f algorithm, due to marker particle weight spreading, is addressed in detail, and a solution to this problem is proposed. To obtain higher resolution in critical regions of phase space, a practical procedure for implementing sources and sinks of marker particles is developed. As a proof of principal, this set of methods is applied for computing electrical Spitzer conductivity as well as collisional absorption in a homogeneous plasma. (C) 1999 American Institute of Physics. [S1070-664X(99)02912-2]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. EM sbrunner@pppl.gov RI Brunner, Stephan/B-6200-2009 OI Brunner, Stephan/0000-0001-7588-7476 NR 24 TC 60 Z9 60 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4504 EP 4521 DI 10.1063/1.873738 PG 18 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900014 ER PT J AU Brizard, AJ Chan, AA AF Brizard, AJ Chan, AA TI Nonlinear relativistic gyrokinetic Vlasov-Maxwell equations SO PHYSICS OF PLASMAS LA English DT Article ID RUNAWAY ELECTRONS; MAGNETIC-FIELD; TOKAMAK; MAGNETOSPHERE; GENERATION; PARTICLES; TRANSPORT; PLASMAS; TEXTOR AB A set of self-consistent nonlinear gyrokinetic equations is derived for relativistic charged particles in a general nonuniform magnetized plasma. Full electromagnetic-field fluctuations are considered with spatial and temporal scales given by the low-frequency gyrokinetic ordering. Self-consistency is obtained by combining the nonlinear relativistic gyrokinetic Vlasov equation with the low-frequency Maxwell equations in which charge densities and current densities are expressed in terms of moments of the gyrokinetic Vlasov distribution. For these self-consistent gyrokinetic equations, a low-frequency energy conservation law is also derived. (C) 1999 American Institute of Physics. [S1070-664X(99)01012-5]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Rice Univ, Dept Space Phys & Astron, Houston, TX 77005 USA. RP Brizard, AJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. OI Brizard, Alain/0000-0002-0192-6273 NR 39 TC 33 Z9 33 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4548 EP 4558 DI 10.1063/1.873742 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900018 ER PT J AU Carreras, BA Balbin, R van Milligen, B Pedrosa, MA Garcia-Cortes, I Sanchez, E Hidalgo, C Bleuel, J Endler, M Thomsen, H Chankin, A Davies, S Erents, K Matthews, GF AF Carreras, BA Balbin, R van Milligen, B Pedrosa, MA Garcia-Cortes, I Sanchez, E Hidalgo, C Bleuel, J Endler, M Thomsen, H Chankin, A Davies, S Erents, K Matthews, GF TI Characterization of the frequency ranges of the plasma edge fluctuation spectra SO PHYSICS OF PLASMAS LA English DT Article ID TURBULENCE; TOKAMAK AB Frequency spectra of fluctuations for the ion saturation current, floating potential, and turbulent transport measured in the plasma edge of plasma confinement experiments (tokamaks and stellarators) have been analyzed to identify the frequency ranges characterized by a power dependence. Three main regions can be identified. For the intermediate frequency region, the decay of the spectra is close to 1/f, as is expected in self-organized criticality systems. This region is particularly important for the role that it plays in plasma transport and the self-similarity of the fluctuations and fluxes. The effect of plasma rotation on the decay indices has also been studied. (C) 1999 American Institute of Physics. [S1070-664X(99)00212-8]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. CIEMAT, Asociac Euratom, E-28040 Madrid, Spain. Max Planck Inst Plasma Phys, EURATOM Assoc, D-85740 Garching, Germany. JET Joint Undertaking, Abingdon OX14 3EA, Oxon, England. RP Carreras, BA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Sanchez, Edilberto/D-4620-2009; van Milligen, Boudewijn/H-5121-2015; Garcia-Cortes, Isabel/H-3341-2015; Balbin, Rosa/F-8210-2010 OI Sanchez, Edilberto/0000-0003-1062-7870; van Milligen, Boudewijn/0000-0001-5344-6274; Garcia-Cortes, Isabel/0000-0002-5223-391X; Balbin, Rosa/0000-0001-5231-1300 NR 18 TC 27 Z9 27 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 DEC PY 1999 VL 6 IS 12 BP 4615 EP 4621 DI 10.1063/1.873748 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900025 ER PT J AU Zakharov, LE Pletzer, A AF Zakharov, LE Pletzer, A TI Theory of perturbed equilibria for solving the Grad-Shafranov equation SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOHYDRODYNAMIC EQUILIBRIA; TOKAMAK EQUILIBRIA; MHD EQUILIBRIA; RECONSTRUCTION; PROFILE; COMPUTATION; DIFFUSION; EVOLUTION; CODE AB The theory of perturbed magnetohydrodynamic equilibria is presented for different formulations of the tokamak equilibrium problem. For numerical codes, it gives an explicit Newton scheme for solving the Grad-Shafranov equation subject to different constraints. The problem of stability of axisymmetric modes is shown to be a particular case of the equilibrium perturbation theory. (C) 1999 American Institute of Physics. [S1070-664X(99)03012-8]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Zakharov, LE (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 42 TC 57 Z9 57 U1 2 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4693 EP 4704 DI 10.1063/1.873756 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900033 ER PT J AU Rewoldt, G Ku, LP Tang, WM Cooper, WA AF Rewoldt, G Ku, LP Tang, WM Cooper, WA TI Drift mode calculations in nonaxisymmetric geometry SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOHYDRODYNAMIC EQUILIBRIA; BALLOONING INSTABILITIES; STABILITY; STELLARATOR; SPECTRUM; PLASMAS AB A fully kinetic assessment of the stability properties of toroidal drift modes has been obtained for nonaxisymmetric (stellarator) geometry, in the electrostatic limit. This calculation is a comprehensive solution of the linearized gyrokinetic equation, using the lowest-order "ballooning representation" for high toroidal mode number instabilities, with a model collision operator. Results for toroidal drift waves destabilized by temperature gradients and/or trapped particle dynamics are presented, using three-dimensional magnetohydrodynamic equilibria generated as part of a design effort for a quasiaxisymmetric stellarator. Comparisons of these results with those obtained for typical tokamak cases indicate that the basic trends are similar. (C) 1999 American Institute of Physics. [S1070- 664X(99)03212-7]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Ecole Polytech Fed Lausanne, Ctr Rech Phys Plasmas, PPB Ecublens, CH-1015 Lausanne, Switzerland. RP Rewoldt, G (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 23 TC 25 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4705 EP 4713 DI 10.1063/1.873757 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900034 ER PT J AU Bel'kov, SA Mkhitarian, LS Vinokurov, OA Wilson, DC Goldman, SR AF Bel'kov, SA Mkhitarian, LS Vinokurov, OA Wilson, DC Goldman, SR TI Radiation hydrodynamic effects in two beryllium plates with an idealized aluminum joint SO PHYSICS OF PLASMAS LA English DT Article ID NATIONAL-IGNITION-FACILITY AB A beryllium capsule formed from two hemispherical shells with a thin bond is one possible ignition target for the National Ignition Facility [J. A. Paisner , Laser Focus World 30, 75 (1994)] Nonuniformities in density, opacity, and interface position at the joint between these hemishells will initiate two-dimensional (2-D) perturbations of the shock wave and material behind the shock as the shock passes through the shell perpendicular to the joint width. Rarefaction of material flow behind the shock front can cause the interface between the shell and joint material to oscillate in position. The amplitude of these oscillations may be comparable to the joint width. The evolution of these perturbations is studied by numerically simulating shock passage through flat beryllium plates containing aluminum joints. Using the MIMOSA-ND code [D. Sofronov , Vopr. At. Nauki Tekh., Ser: Mat. modelirovanie fizicheskih processov 2, 3 (1990)] two different cases are calculated-a wide (10 mu m) and a narrow (1 mu m) joint of aluminum between two 150 mu m long semiinfinite beryllium plates. Both cases showed good agreement with an analytic representation of the oscillation behavior. For the narrow joint, a special technique allows the calculation of mixing between the joint and surrounding material caused by the Kelvin-Helmholtz instability. (C) 1999 American Institute of Physics. [S1070-664X(99)02411-8]. C1 Russian Fed Nucl Ctr, Inst Expt Phys, Sarov 607190, Nizhny Novgorod, Russia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Russian Fed Nucl Ctr, Inst Expt Phys, Sarov 607190, Nizhny Novgorod, Russia. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4728 EP 4738 DI 10.1063/1.873760 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900037 ER PT J AU Lewandowski, JLV AF Lewandowski, JLV TI Drift wave simulations with reduced stellarator equilibria SO PHYSICS OF PLASMAS LA English DT Article AB A three-field model to study drift-resistive, low-frequency waves in low-beta, nonaxisymmetric plasmas [J. L. V. Lewandowski, Phys. Plasmas 4, 4023 (1997)] is used to analyze the effect of the inhomogeneities in the stellarator magnetic field on the fastest (linear) growth rate, gamma. Extensive numerical calculations for a toroidal heliac show that not all Fourier components in the representation of the equilibrium configuration are important as far as gamma is concerned. (C) 1999 American Institute of Physics. [S1070-664X(99)03112-2]. 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 6 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4788 EP 4790 DI 10.1063/1.873769 PG 3 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900046 ER PT J AU Mendel, CW Seidel, DB AF Mendel, CW Seidel, DB TI Flow impedance in a uniform magnetically insulated transmission line SO PHYSICS OF PLASMAS LA English DT Article AB In two recent publications [C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas 2, 1332 (1995), C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas 3, 4207 (1996)] relativistic electron flow in cylindrical magnetically insulated transmission lines was analyzed and modeled under the assumption of negligible electron pressure. The model allows power flow in these lines to be accurately calculated under most conditions. The model was developed for coaxial right circular cylindrical electrodes. It is shown here that the model applies equally well to arbitrary cylindrical systems, i.e., systems consisting of electrodes of arbitrary cross section. (C) 1999 American Institute of Physics. [S1070-664X(99)03712-X]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Cove Consulting, Albuquerque, NM 87110 USA. RP Mendel, CW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 4 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 1999 VL 6 IS 12 BP 4791 EP 4793 DI 10.1063/1.873770 PG 3 WC Physics, Fluids & Plasmas SC Physics GA 255TH UT WOS:000083685900047 ER PT J AU Reese, CC Solomatov, VS Baumgardner, JR Yang, WS AF Reese, CC Solomatov, VS Baumgardner, JR Yang, WS TI Stagnant lid convection in a spherical shell SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article DE stagnant lid convection; planetary heat flow; mantle rheology ID TEMPERATURE-DEPENDENT VISCOSITY; THERMAL-CONVECTION; VARIABLE VISCOSITY; MANTLE; FLUID; EVOLUTION; VENUS AB A compelling explanation for the observed lack of mobile surface plates on the terrestrial planets is that the strong temperature dependence of silicate rheology leads to a quasi-rigid stagnant lid at the cool surface of the convecting planetary mantle. We investigate such stagnant lid convection in an internally heated spherical shell. For the parameter range we study, convection beneath the lid is steady in time and characterized by cylindrical upwellings surrounded by cold sheet-like downwellings that exhibit dodecahedronal (l = 6, m = {0,5}) symmetry. The scaling relationship we obtain for the heat flux is very similar to results from two-dimensional numerical experiments and asymptotic boundary layer analyses. It seems that the predictions of two-dimensional models, in particular, low heat transport efficiency and extensive melting, also apply in fully three-dimensional spherical geometry. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Inst Geophys & Planetary Phys, Los Alamos, NM 87545 USA. RP Reese, CC (reprint author), New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. NR 27 TC 33 Z9 34 U1 2 U2 5 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 DEC PY 1999 VL 116 IS 1-4 BP 1 EP 7 DI 10.1016/S0031-9201(99)00115-6 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 262ND UT WOS:000084072600001 ER PT J AU Afanasjev, AV Fossan, DB Lane, GJ Ragnarsson, I AF Afanasjev, AV Fossan, DB Lane, GJ Ragnarsson, I TI Termination of rotational bands: Disappearance of quantum many-body collectivity SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review DE rotational bands; band termination; quantum many-body collectivity; cranked Nilsson-Strutinsky model; compton suppressed gamma-ray detector array ID HIGH-SPIN STATES; GAMMA-RAY SPECTROSCOPY; INTERACTING BOSON MODEL; FOCK-BOGOLIUBOV THEORY; ORTHOGONALITY CONDITION MODEL; HIGH ANGULAR-MOMENTUM; MEAN-FIELD-THEORY; FULL PF SHELL; EXCITED-STATES; SUPERDEFORMED BANDS AB One of the most interesting features of nuclei is the process by which specific configurations, manifest as collective rotational bands at intermediate spin values, gradually lose their collectivity and terminate in a non-collective state at the maximum spin which can be built within the configuration. Recent advances in both experiment and theory allow the study of this nuclear structure feature in detail. The bands, which show such a continuous transition from high collectivity to a pure particle-hole (terminating) state, are generally called terminating bands or to underline their continuous character, smooth terminating bands. The best examples of such bands known at present are in the neutron-deficient A similar to 110 mass region, where terminating configurations involving proton particle-hole excitations across the Z = 50 gap can be observed over their entire spin range. The main features of band termination as a specific high-spin phenomenon inherent to finite many-fermion strongly interacting systems are overviewed, based mainly on the configuration-dependent cranked Nilsson-Strutinsky approach. The extensive experimental results on smooth terminating bands in the A similar to 110 mass region, which have been addressed by these theoretical calculations, are presented along with the theoretical comparisons in a systematic way. In addition, specific features of band termination in other parts of the periodic chart and other possible theoretical approaches are briefly reviewed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lund Inst Technol, Dept Math Phys, S-22100 Lund, Sweden. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Tech Univ Munich, Dept Phys, D-85747 Garching, Germany. Latvian Acad Sci, Nucl Res Ctr, LV-2169 Salaspils, Latvia. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Afanasjev, AV (reprint author), Lund Inst Technol, Dept Math Phys, POB 118, S-22100 Lund, Sweden. RI Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 264 TC 242 Z9 244 U1 0 U2 5 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 DEC PY 1999 VL 322 IS 1-2 BP 1 EP 124 DI 10.1016/S0370-1573(99)00035-6 PG 124 WC Physics, Multidisciplinary SC Physics GA 253EA UT WOS:000083542600001 ER PT J AU Zweiback, J AF Zweiback, J TI 'Entropy engine' fuels discussion of PT ad policies SO PHYSICS TODAY LA English DT Letter C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Zweiback, J (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 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 DEC PY 1999 VL 52 IS 12 BP 79 EP 79 PG 1 WC Physics, Multidisciplinary SC Physics GA 263UA UT WOS:000084142600022 ER PT J AU Stevens, M AF Stevens, M TI Clash on research priorities concludes on dissonant note SO PHYSICS TODAY LA English DT Letter C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Stevens, M (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD DEC PY 1999 VL 52 IS 12 BP 81 EP 81 DI 10.1063/1.882919 PG 1 WC Physics, Multidisciplinary SC Physics GA 263UA UT WOS:000084142600026 ER PT J AU Campbell, EM Hogan, WJ AF Campbell, EM Hogan, WJ TI The National Ignition Facility - applications for inertial fusion energy and high-energy-density science SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 26th European-Physical-Society Conference on Controlled Fusion and Plasma Physics CY JUN 14-18, 1999 CL MAASTRICHT, NETHERLANDS SP FOM Rijnhuizen, Netherlands, ERM/KMS Brussels, Belgium, Forschung Julich, Germany, European Phys Soc, Plasma Phys Div ID HOT-ELECTRONS; NOVA LASER; INSTABILITY; TARGETS AB Research in inertial fusion sciences and applications worldwide is making dramatic progress. The National Ignition Facility (MF) in the US and the Laser MegaJoule (LMJ) in France are being built to achieve fusion ignition in the laboratory. Experiments that have been done on current Inertial Confinement Fusion (ICF) facilities in the US and around the world have demonstrated that the drive characteristics required for ignition are now well understood and a new plan for inertial fusion energy development has been put together by the community. Besides examining the conditions necessary for fusion ignition, targets were designed without fusion capsules. Equilibrium temperatures of hundreds of electron volts and megabar pressures were used to study astrophysical processes and measure equations of states at these extreme conditions. Recent studies of laser-matter interactions with femtosecond lasers have revealed some startling new phenomena due to the ability to achieve irradiances > 1020 W cm(-2). This paper will review recent results in fusion and high energy density science achieved by high intensity lasers at LLNL and will look ahead to what may achieved on NIF. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Campbell, EM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 28 TC 46 Z9 47 U1 3 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD DEC PY 1999 VL 41 SU 12B BP B39 EP B56 DI 10.1088/0741-3335/41/12B/303 PG 18 WC Physics, Fluids & Plasmas SC Physics GA 275PV UT WOS:000084829300004 ER PT J AU Luce, TC Lin-Liu, YR Harvey, RW Giruzzi, G Lohr, JM Petty, CC Politzer, PA Prater, R Rice, BW AF Luce, TC Lin-Liu, YR Harvey, RW Giruzzi, G Lohr, JM Petty, CC Politzer, PA Prater, R Rice, BW TI Modification of the current profile in DIII-D by off-axis electron cyclotron current drive SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 26th European-Physical-Society Conference on Controlled Fusion and Plasma Physics CY JUN 14-18, 1999 CL MAASTRICHT, NETHERLANDS SP FOM Rijnhuizen, Netherlands, ERM/KMS Brussels, Belgium, Forschung Julich, Germany, European Phys Soc, Plasma Phys Div ID TOKAMAK PLASMAS AB Localized non-inductive currents clue to electron cyclotron wave absorption have been measured on the DIII-D tokamak. Clear evidence of non-inductive currents is seen on the internal magnetic field measurements by motional Stark effect spectroscopy. The magnitude and location of the non-inductive current is evaluated by comparing the total and ohmic current profiles of discharges with and without electron cyclotron wave power. The measured current agrees with Fokker-Planck calculations near the magnetic axis, but exceeds the predicted value as the location of the current drive is moved to the half-radius. C1 Gen Atom Co, San Diego, CA 92186 USA. CompX, Del Mar, CA 92014 USA. CEA, Ctr Etud Cadarache, F-13108 St Paul Durance, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Luce, TC (reprint author), Gen Atom Co, POB 85608, San Diego, CA 92186 USA. NR 7 TC 16 Z9 17 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD DEC PY 1999 VL 41 SU 12B BP B119 EP B127 DI 10.1088/0741-3335/41/12B/308 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 275PV UT WOS:000084829300009 ER PT J AU Morris, AW Akers, RJ Connor, JW Counsell, GF Fonck, RJ Gryaznevich, MP Gusev, V Hender, TC Kaye, SM Maddison, GP Majeski, R Martin, TJ McClements, KG Medvedev, S Peng, YKM Roach, CM Robinson, DC Sharapov, S Sykes, A Valovic, M Walsh, MJ Wilson, HR AF Morris, AW Akers, RJ Connor, JW Counsell, GF Fonck, RJ Gryaznevich, MP Gusev, V Hender, TC Kaye, SM Maddison, GP Majeski, R Martin, TJ McClements, KG Medvedev, S Peng, YKM Roach, CM Robinson, DC Sharapov, S Sykes, A Valovic, M Walsh, MJ Wilson, HR TI The role of the spherical tokamak in clarifying tokamak physics SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 26th European-Physical-Society Conference on Controlled Fusion and Plasma Physics CY JUN 14-18, 1999 CL MAASTRICHT, NETHERLANDS SP FOM Rijnhuizen, Netherlands, ERM/KMS Brussels, Belgium, Forschung Julich, Germany, European Phys Soc, Plasma Phys Div ID PERFORMANCE; PLASMAS; START; CONFINEMENT; TRANSPORT; SHEAR; BETA AB The spherical tokamak (ST) provides a unique environment in which to perform complementary and exacting tests of the tokamak physics required for a burning plasma experiment of any aspect ratio, while also having the potential for long-term fusion applications in its own right. New experiments are coming on-line in the UR (MAST), USA (NSTX, Pegasus), Russia (Globus-M), Brazil (ETE) and elsewhere, and the status of these devices will be reported, along with newly-analysed data from START. Those physics issues where the ST provides an opportunity to remove degeneracy in the databases or clarify one's understanding will be emphasized. C1 UKAEA Euratom Fus Assoc, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England. Univ Wisconsin, Dept Engn Phys, Madison, WI USA. AF Ioffe Physicotech Inst, St Petersburg, Russia. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Russian Acad Sci, MV Keldysh Appl Math Inst, Moscow, Russia. Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. Walsh Sci, Culham Sci Ctr, Abingdon, Oxon, England. RP Morris, AW (reprint author), UKAEA Euratom Fus Assoc, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England. RI Medvedev, Sergey/C-3492-2016 OI Medvedev, Sergey/0000-0002-9358-9402 NR 67 TC 7 Z9 7 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD DEC PY 1999 VL 41 SU 12B BP B191 EP B207 DI 10.1088/0741-3335/41/12B/314 PG 17 WC Physics, Fluids & Plasmas SC Physics GA 275PV UT WOS:000084829300015 ER PT J AU Reiman, A Fu, G Hirshman, S Ku, L Monticello, D Mynick, H Redi, M Spong, D Zarnstorff, M Blackwell, B Boozer, A Brooks, A Cooper, WA Drevlak, M Goldston, R Harris, J Isaev, M Kessel, C Lin, Z Lyon, JF Merkel, P Mikhailov, M Miner, W Nakajima, N Neilson, G Nuhrenberg, C Okamoto, M Pomphrey, N Reiersen, W Sanchez, R Schmidt, J Subbotin, A Valanju, P Watanabe, KY White, R AF Reiman, A Fu, G Hirshman, S Ku, L Monticello, D Mynick, H Redi, M Spong, D Zarnstorff, M Blackwell, B Boozer, A Brooks, A Cooper, WA Drevlak, M Goldston, R Harris, J Isaev, M Kessel, C Lin, Z Lyon, JF Merkel, P Mikhailov, M Miner, W Nakajima, N Neilson, G Nuhrenberg, C Okamoto, M Pomphrey, N Reiersen, W Sanchez, R Schmidt, J Subbotin, A Valanju, P Watanabe, KY White, R TI Physics design of a high-beta quasi-axisymmetric stellarator SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 26th European-Physical-Society Conference on Controlled Fusion and Plasma Physics CY JUN 14-18, 1999 CL MAASTRICHT, NETHERLANDS SP FOM Rijnhuizen, Netherlands, ERM/KMS Brussels, Belgium, Forschung Julich, Germany, European Phys Soc, Plasma Phys Div ID TOKAMAK AB Key physics issues in the design of a high-beta quasi-axisymmetric stellarator configuration are discussed. The goal of the design study is a compact stellarator configuration with aspect ratio comparable to that of tokamaks and good transport and stability properties. Quasi-axisymmetry has been used to provide good drift trajectories. Ballooning stabilization has been accomplished by strong axisymmetric shaping, yielding a stellarator configuration whose core is in the second stability regime for ballooning modes. A combination of externally generated shear and non-axisymmetric corrugation of the plasma boundary provides stability to external kink modes even in the absence of a conducting wall. The resulting configuration is also found to be robustly stable to vertical modes, increasing the freedom to perform axisymmetric shaping. Stability to neoclassical tearing modes is conferred by a monotonically increasing i profile. A gyrokinetic delta f code has been used to confirm the adequacy of the neoclassical confinement. Neutral beam losses have been evaluated with Monte Carlo codes. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Australian Natl Univ, Plasma Res Lab, Canberra, ACT, Australia. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. PPB, CRPP, CH-1015 Lausanne, Switzerland. EURATOM, IPP, D-17491 Greifswald, Germany. IV Kurchatov Atom Energy Inst, Moscow 123182, Russia. Univ Texas, Austin, TX 78712 USA. Natl Inst Fus Sci, Nagoya, Aichi, Japan. RP Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Sanchez, Raul/C-2328-2008; pomphrey, neil/G-4405-2010; Spong, Donald/C-6887-2012; White, Roscoe/D-1773-2013; Isaev, Maxim/A-7910-2012 OI Spong, Donald/0000-0003-2370-1873; White, Roscoe/0000-0002-4239-2685; Isaev, Maxim/0000-0002-8492-0650 NR 26 TC 30 Z9 30 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD DEC PY 1999 VL 41 SU 12B BP B273 EP B283 DI 10.1088/0741-3335/41/12B/320 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 275PV UT WOS:000084829300021 ER PT J AU Johnson, JL AF Johnson, JL TI On magnetohydrodynamic equilibrium and stability in stellarators SO PLASMA PHYSICS REPORTS LA English DT Review ID PLASMA CONFIGURATIONS; MODES AB Although the ideal MHD model is difficult to justify for fusion plasma devices, it has provided much guidance in the design of stellarator and tokamak devices. A few ideas that arise from this model are considered. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Johnson, JL (reprint author), Princeton Univ, Plasma Phys Lab, Forrestal Campus, Princeton, NJ 08543 USA. NR 31 TC 0 Z9 0 U1 1 U2 1 PU MAIK NAUKA/INTERPERIODICA/SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013-1578 USA SN 1063-780X EI 1562-6938 J9 PLASMA PHYS REP+ JI Plasma Phys. Rep. PD DEC PY 1999 VL 25 IS 12 BP 933 EP 942 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 296UG UT WOS:000086044300001 ER PT J AU Rognlien, TD Ryutov, DD AF Rognlien, TD Ryutov, DD TI Pseudoclassical transport equations for magnetized edge-plasmas in the slab approximation SO PLASMA PHYSICS REPORTS LA English DT Article ID SCRAPE-OFF LAYER; ELECTRIC-FIELD; DIII-D; TOKAMAK; DIVERTOR; CONFINEMENT; SIMULATION; TURBULENCE; DRIFTS; MODEL AB The classical fluid transport equations are analyzed in a magnetized slab geometry containing two regions, the first being where the magnetic field lines are in contact with material surfaces and the second adjoining region where fields lines form closed flux surfaces. These fluid equations are used as a framework to describe the transport of particles, momentum, and energy. Anomalous transport across the magnetic field arising from turbulence is modeled by assuming enhancement of the classical terms in a systematic manner by increasing the collision frequencies, thereby retaining the basic symmetry and conservation properties of the ion and electron system. A reduced set of equations is derived for the plasma edge region by taking advantage of the strong magnetic field and long-thin geometry of the edge to eliminate variables and subdominant terms. As a specific example, parameters typical of the tokamak edge region are considered. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rognlien, TD (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 32 TC 13 Z9 13 U1 1 U2 2 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-780X J9 PLASMA PHYS REP JI Plasma Phys. Rep. PD DEC PY 1999 VL 25 IS 12 BP 943 EP 957 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 296UG UT WOS:000086044300002 ER PT J AU Carreras, BA Lynch, VE Ichiguchi, K Tatsumo, T Wakatani, M AF Carreras, BA Lynch, VE Ichiguchi, K Tatsumo, T Wakatani, M TI On the beta-limit induced by ideal interchange modes in stellarator configurations SO PLASMA PHYSICS REPORTS LA English DT Article ID STABILITY AB The theoretically determined ideal interchange beta-limit for stellarator devices is generally lower than the operational beta values in the experiment. Usually, these beta-limit determinations are based on the assumption of smooth pressure profiles. However, when staircaselike pressure profiles are considered, the beta-limit increases. These types of profiles may be the result of the nonlinear profile modification by the resistive branch of the interchange instability. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Fus Sci, Toki 5095292, Japan. Kyoto Univ, Grad Sch Energy Sci, Kyoto, Japan. RP Carreras, BA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Lynch, Vickie/J-4647-2012 OI Lynch, Vickie/0000-0002-5836-7636 NR 12 TC 4 Z9 4 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-780X J9 PLASMA PHYS REP JI Plasma Phys. Rep. PD DEC PY 1999 VL 25 IS 12 BP 958 EP 962 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 296UG UT WOS:000086044300003 ER PT J AU Weinberg, AM AF Weinberg, AM TI Scientific millenarianism SO PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY LA English DT Article C1 Oak Ridge Associated Univ, Oak Ridge, TN 37830 USA. RP Weinberg, AM (reprint author), Oak Ridge Associated Univ, Oak Ridge, TN 37830 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER PHILOSOPHICAL SOC PI PHILADELPHIA PA 104 SOUTH FIFTH ST, PHILADELPHIA, PA 19106-3387 USA SN 0003-049X J9 P AM PHILOS SOC JI Proc. Amer. Philos. Soc. PD DEC PY 1999 VL 143 IS 4 BP 531 EP 539 PG 9 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 287JB UT WOS:000085501800001 ER PT J AU Kasprzyk, DJ Bell, DA Flesner, RL Larson, SA AF Kasprzyk, DJ Bell, DA Flesner, RL Larson, SA TI Characterization of a slurry process used to make a plastic-bonded explosive SO PROPELLANTS EXPLOSIVES PYROTECHNICS LA English DT Article AB The effects of agitation rate, air sweep rate, and reactor temperature in the production of PBX 9501, a plastic-bonded explosive molding powder, were investigated. These variables affected the agglomerate length, the agglomerate shape, and the bulk density of the molding powder, but had very little effect on the properties of pressed pieces made from the molding powder. C1 Univ Wyoming, Dept Chem & Petr Engn, Laramie, WY 82071 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Bell, DA (reprint author), Univ Wyoming, Dept Chem & Petr Engn, Laramie, WY 82071 USA. NR 6 TC 9 Z9 11 U1 2 U2 2 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0721-3115 J9 PROPELL EXPLOS PYROT JI Propellants Explos. Pyrotech. PD DEC PY 1999 VL 24 IS 6 BP 333 EP 338 DI 10.1002/(SICI)1521-4087(199912)24:6<333::AID-PREP333>3.3.CO;2-K PG 6 WC Chemistry, Applied; Engineering, Chemical SC Chemistry; Engineering GA 276LH UT WOS:000084878900002 ER PT J AU Bowie, JU AF Bowie, JU TI Helix-bundle membrane protein fold templates SO PROTEIN SCIENCE LA English DT Article DE fold recognition; helix packing; protein folds; transmembrane helices ID AMINO-ACID-SEQUENCES; CRYSTALLOGRAPHIC REFINEMENT; 3-DIMENSIONAL STRUCTURE; TRANSMEMBRANE DOMAIN; STRUCTURE PREDICTION; BACTERIORHODOPSIN; RECOGNITION; RESOLUTION; FAMILIES; PACKING AB In the fold recognition approach to structure prediction, a sequence is tested for compatibility with an already known fold. For membrane proteins, however, few folds have been determined experimentally. Here the feasibility of computing the vast majority of likely membrane protein folds is tested. The results indicate that conformation space can be effectively sampled for small numbers of helices. The vast majority of potential monomeric membrane protein structures can be represented by about 30-folds for three helices, but increases exponentially to about 1,500,000 folds for seven helices. The generated folds could serve as templates for fold recognition or as starting points for conformational searches that are well distributed throughout conformation space. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Bowie, JU (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 405 Hilgard Ave, Los Angeles, CA 90095 USA. NR 35 TC 34 Z9 35 U1 0 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD DEC PY 1999 VL 8 IS 12 BP 2711 EP 2719 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 266RP UT WOS:000084314100018 PM 10631987 ER PT J AU Wall, ME Subramaniam, S Phillips, GN AF Wall, ME Subramaniam, S Phillips, GN TI Protein structure determination using a database of interatomic distance probabilities SO PROTEIN SCIENCE LA English DT Article DE knowledge-based modeling; low-resolution; molecular dynamics; structure refinement; X-ray crystallography ID STRUCTURE REFINEMENT; DYNAMICS AB The accelerated pace of genomic sequencing has increased the demand for structural models of gene products. Improved quantitative methods are needed to study the many systems (e.g., macromolecular assemblies) for which data are scarce. Here, we describe a new molecular dynamics method for protein structure determination and molecular modeling. An energy function, or database potential, is derived from distributions of interatomic distances obtained from a database of known structures. X-ray crystal structures are refined by molecular dynamics with the new energy function replacing the Van der Waals potential. Compared to standard methods, this method improved the atomic positions, interatomic distances, and side-chain dihedral angles of structures randomized to mimic the early stages of refinement. The greatest enhancement in side-chain placement was observed for groups that are characteristically buried. More accurate calculated model phases will follow from improved interatomic distances. Details usually seen only in high-resolution refinements were improved, as is shown by an R-factor analysis. The improvements were greatest when refinements were carried out using X-ray data truncated at 3.5 Angstrom. The database potential should therefore be a valuable tool for determining X-ray structures, especially when only low-resolution data are available. C1 Rice Univ, Dept Biochem & Cell Biol, Houston, TX 77005 USA. Rice Univ, Keck Ctr Computat Biol, Houston, TX 77005 USA. Univ Illinois, Beckman Inst Adv Sci & Technol, Dept Biochem, Urbana, IL 61801 USA. Univ Illinois, Beckman Inst Adv Sci & Technol, Dept Mol & Integrat Biol, Urbana, IL 61801 USA. Univ Illinois, Beckman Inst Adv Sci & Technol, Dept Chem Engn, Urbana, IL 61801 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. RP Wall, ME (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, MSG758, Los Alamos, NM 87545 USA. FU NIAMS NIH HHS [AR 40252] NR 28 TC 11 Z9 14 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD DEC PY 1999 VL 8 IS 12 BP 2720 EP 2727 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 266RP UT WOS:000084314100019 PM 10631988 ER PT J AU Sorenson, JM Head-Gordon, T AF Sorenson, JM Head-Gordon, T TI Redesigning the hydrophobic core of a model beta-sheet protein: Destabilizing traps through a threading approach SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE protein design; off-lattice models; protein folding; multiple histogram method; multistate kinetics ID PHASE-TRANSITIONS; GLOBULAR-PROTEINS; FOLDING KINETICS; LANDSCAPE PERSPECTIVE; ENERGY LANDSCAPE; LATTICE MODELS; FOLDED STATES; DYNAMICS; SEQUENCES; PATHWAYS AB An off-lattice 46-bead model of a small all-beta protein has been recently criticized for possessing too many traps and long-lived intermediates compared with the folding energy landscape predicted for real proteins and models using the principle of minimal frustration. Using a novel sequence design approach based on threading for finding beneficial mutations for destabilizing traps, we proposed three new sequences for folding in the beta-sheet model. Simulated annealing on these sequences found the global minimum more reliably, indicative of a smoother energy landscape, and simulated thermodynamic variables found evidence for a more cooperative collapse transition, lowering of the collapse temperature, and higher folding temperatures. Folding and unfolding kinetics were acquired by calculating first-passage times, and the new sequences were found to fold significantly faster than the original sequence, with a concomitant lowering of the glass temperature, although none of the sequences have highly stable native structures. The new sequences found here are more representative of real proteins and are good folders in the T-f > T-g sense, and they should prove useful in future studies of the details of transition states and the nature of folding intermediates in the context of simplified folding models. These results show that our sequence design approach using threading can improve models possessing glasslike folding dynamics. Proteins 1999;37:582-591. Published 1999 Wiley-Liss, Inc.dagger C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci & Life Sci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Head-Gordon, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci & Life Sci Div, Berkeley, CA 94720 USA. RI Head-Gordon, Teresa/E-5818-2011 NR 70 TC 24 Z9 25 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD DEC 1 PY 1999 VL 37 IS 4 BP 582 EP 591 DI 10.1002/(SICI)1097-0134(19991201)37:4<582::AID-PROT9>3.0.CO;2-M PG 10 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 261DK UT WOS:000083993200009 PM 10651274 ER PT J AU Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Geha, M Griest, K Lehner, MJ Marshall, SL Minniti, D Peterson, BA Popowski, P Pratt, MR Nelson, CA Quinn, PJ Stubbs, CW Sutherland, W Tomaney, AB Vandehei, T Welch, DL AF Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Geha, M Griest, K Lehner, MJ Marshall, SL Minniti, D Peterson, BA Popowski, P Pratt, MR Nelson, CA Quinn, PJ Stubbs, CW Sutherland, W Tomaney, AB Vandehei, T Welch, DL CA MACHO Collaboration TI Calibration of the MACHO photometry database SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID RR LYRAE STARS; MAGELLANIC-CLOUD; STELLAR PHOTOMETRY; STANDARD STARS; COUSINS; PROGRAM; SYSTEM; BINARY; HALO AB The MACHO Project is a microlensing survey that monitors the brightnesses of similar to 60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. Calibrated MACHO photometry may be properly compared with all other observations on the Kron-Cousins standard system, enhancing the astrophysical value of these data. For similar to 9 million stars in the LMC bar, independent photometric measurements of similar to 20,000 stars with V < 18 mag in field-overlap regions demonstrate an internal precision sigma(V) = 0.021, sigma(R) = 0.019, sigma(V-R) = 0.028 mag. The accuracy of the zero point in this calibration is estimated to be +/- 0.035 mag for stars with colors in the range -0.1 mag < V--R < 1.2 mag. A comparison of calibrated MACHO photometry with published photometric sequences and new Hubble Space Telescope observations shows agreement. The current calibration zero-point uncertainty for the remainder of the MACHO photometry database is estimated to be +/-0.10 mag in V or R and +/-0.04 mag in V-R. We describe the first application of calibrated MACHO data: the construction of a color-magnitude diagram used to calculate our experimental sensitivity for detecting microlensing in the LMC. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, Supercomp Facil, Canberra, ACT 0200, Australia. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston Creek, ACT 2611, Australia. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. Pontificia Univ Catolica Chile, Dept Astron, Santiago 22, Chile. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. European So Observ, D-85748 Garching, Germany. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RP Alcock, C (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Stubbs, Christopher/C-2829-2012; Quinn, Peter/B-3638-2013; OI Stubbs, Christopher/0000-0003-0347-1724; Lehner, Matthew/0000-0003-4077-0985 NR 37 TC 114 Z9 115 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD DEC PY 1999 VL 111 IS 766 BP 1539 EP 1558 DI 10.1086/316469 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 262XC UT WOS:000084092700007 ER PT J AU Holden, NE AF Holden, NE TI Temperature dependence of the Westcott g-factor for neutron reactions in activation analysis - (Technical Report) SO PURE AND APPLIED CHEMISTRY LA English DT Article AB The Westcott g-factors, which allow the user to determine reaction rates for nuclear reactions taking place at various temperatures, have been calculated using data from the Evaluated Neutron Nuclear Data Library, ENDF/B-VI. Nuclides chosen have g-factors which are significantly different from unity and result in different reaction rates compared to nuclides whose neutron capture cross-section varies as the reciprocal of the neutron velocity. Values are presented as a function of temperature up to 673.16 K (400 degrees C). C1 Brookhaven Natl Lab, Reactor Div, Upton, NY 11973 USA. RP Holden, NE (reprint author), Brookhaven Natl Lab, Reactor Div, Upton, NY 11973 USA. NR 9 TC 42 Z9 42 U1 0 U2 4 PU INT UNION PURE APPLIED CHEMISTRY PI RES TRIANGLE PK PA 104 TW ALEXANDER DR, PO BOX 13757, RES TRIANGLE PK, NC 27709-3757 USA SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD DEC PY 1999 VL 71 IS 12 BP 2309 EP 2315 DI 10.1351/pac199971122309 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 343XQ UT WOS:000088728300014 ER PT J AU O'Malley, YX Zhao, WL Barcellos-Hoff, MH Robbins, MEC AF O'Malley, YX Zhao, WL Barcellos-Hoff, MH Robbins, MEC TI Radiation-induced alterations in rat mesangial cell Tgfb1 and Tgfb3 gene expression are not associated with altered secretion of active Tgfb isoforms SO RADIATION RESEARCH LA English DT Article ID TRANSFORMING GROWTH-FACTOR; PROMOTER-LUCIFERASE CONSTRUCT; MOLECULAR-WEIGHT COMPLEX; FACTOR-BETA ISOFORMS; EXTRACELLULAR-MATRIX; HUMAN-PLATELETS; FACTOR-BETA-1; PURIFICATION; RECEPTORS; FIBROSIS AB Despite evidence of selective radiation-induced modulation of expression of rat mesangial cell Tgfb gene isoforms, it is unclear whether these changes in gene expression are accompanied by changes in protein secretion. To address this issue, primary cultures of rat mesangial cells (passage number 6-11) were placed in serum-free medium 24 h prior to irradiation with single doses of 0.5-20 Gy of (137)Cs gamma rays. After irradiation, cells were maintained in serum-free medium for a further 24 h, Irradiation of quiescent mesangial cells resulted in a significant (P less than or equal to 0.05) dose-independent increase in steady-state levels of Tgfb1 mRNA 24 h postirradiation. In contrast, steady-state levels of Tgfb3 mRNA exhibited a dose-dependent reduction after irradiation; this reduction was statistically significant after doses of 5 and 10 Gy compared to control cells (P less than or equal to 0.05), These radiation-induced changes in Tgfb gene expression were associated with modest increases in Tgfb protein as determined using mink lung epithelial cells transfected with the Pail promoter-luciferase construct. Twenty-four hours after a single dose of 5 Gy, the total Tgfb protein secreted by the mesangial cells was 181 +/- 2.0% of that secreted by unirradiated control cells (P less than or equal to 0.01), However, this increase was seen in terms of latent Tgfb protein; radiation failed to increase significantly the amount of active Tgfb protein secreted by mesangial cells. Both quiescent and irradiated rat mesangial cells secreted active Tgfb as primarily the Tgfb3 isoform. These data reinforce the need to interpret changes in Tgfb gene expression with caution. (C) 1999 by Radiation Research Society. C1 Univ Iowa, Dept Radiol, Radiat Res Lab, Iowa City, IA 52242 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP O'Malley, YX (reprint author), Univ Iowa, Dept Radiol, Radiat Res Lab, Iowa City, IA 52242 USA. FU NIDDK NIH HHS [DK-51612] NR 39 TC 11 Z9 13 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 DEC PY 1999 VL 152 IS 6 BP 622 EP 628 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 264EW UT WOS:000084168500006 PM 10581532 ER PT J AU Pierce, DA Mendelsohn, ML AF Pierce, DA Mendelsohn, ML TI A model for radiation-related cancer suggested by atomic bomb survivor data SO RADIATION RESEARCH LA English DT Article ID CARCINOGENESIS; ARMITAGE; DOLL AB The age-time patterns of excess cancer risk among A-bomb survivors followed up by the Radiation Effects Research Foundation inevitably carry implications regarding the mechanisms of radiation-related cancer. It has recently been found, quite surprisingly and in contrast to impressions given by the relative risks, that for most solid cancers the excess incidence rates themselves depend very little on age at exposure or time since exposure, but mainly on attained age. This paper investigates a mechanistic model that conforms to these age-time patterns. The essence of the model, which is highly idealized, is that: (a) a cancer is caused by mutations that accumulate in a stem cell throughout life, essentially the Armitage-Doll multistage model, and (b) radiation is a general mutagen that can cause virtually any of these mutations. Although postulate (b) departs from previous modeling considerations, the extent to which it explains various aspects of the data in substantial detail is remarkable. A strength of the model is that, similarly to the Armitage-Doll multistage model but differently from many others, it predicts characteristic age-time patterns of excess rates rather independently of its parameter values. The consequence of (a) is that, in Armitage-Doll fashion, background rates increase throughout life as a power of age. The consequence of (b) is that excess absolute rates do not depend on age at exposure and increase with age to a power one less than that of the background rates. Thus the excess relative risk, which is the ratio of these rates, decreases throughout life as 1/age with no dependence on age at exposure. Although this age pattern of relative risks corresponds closely to the RERF data for solid cancer, the interpretation of such a description is quite different from the usual one in which age at exposure plays a primary role. (C) 1999 by Radiation Research Society. C1 Radiat Effects Res Fdn, Dept Stat, Minami Ku, Hiroshima 7320815, Japan. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Pierce, DA (reprint author), Radiat Effects Res Fdn, Dept Stat, Minami Ku, 5-2 Hijiyama Pk, Hiroshima 7320815, Japan. NR 19 TC 58 Z9 62 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 DEC PY 1999 VL 152 IS 6 BP 642 EP 654 DI 10.2307/3580260 PG 13 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 264EW UT WOS:000084168500009 PM 10581535 ER PT J AU Moore, DH Tucker, JD AF Moore, DH Tucker, JD TI Biological dosimetry of Chernobyl cleanup workers: Inclusion of data on age and smoking provides improved radiation dose estimates SO RADIATION RESEARCH LA English DT Article ID IN-SITU HYBRIDIZATION; INDUCED TRANSLOCATIONS; CYTOGENETIC DAMAGE; HUMAN-LYMPHOCYTES; ABERRATIONS; PERSISTENCE; IRRADIATION; EXPOSURE; VITRO AB We report the results of a study of chromosome translocations in 126 Russian subjects who participated in the cleanup activities at Chernobyl and another 53 subjects, from other places in Russia, who were not exposed at Chernobyl, In agreement:with our earlier study, we find increased translocation frequencies among the exposed compared to Russian controls. We describe statistical methods for estimating the dose of ionizing radiation determined by scoring chromosome translocations found in circulating lymphocytes sampled several years after exposure. Two statistical models were fitted to the data. One model assumed that translocation frequencies followed an overdispersed Poisson distribution. The second model assumed that translocation frequencies followed a negative binomial distribution, In addition, the effects of radiation exposure were modeled as additive or as multiplicative to the effects of age and smoking history. We found that the negative binomial model fit the data better than the overdispersed Poisson model. We could not distinguish between the additive and the multiplicative model with our data. Individual dose estimates ranged from 0 (for 43 subjects) to 0.56 Gy (mean 0.14 Gy) under the multiplicative model and from 0 to 0.95 Gy (mean 0.15 Gy) under the additive model. Dose estimates were similar under the two models when the number of translocations was less than 4 per 100 cells. The additive model tended to estimate larger doses when the number of translocations was greater than 4 per 100 cells, We also describe a method for estimating upper 95% tolerance bounds for numbers of translocations in unexposed individuals. We found that inclusion of data on age and smoking history was important for dose estimation. Ignoring these factors could result in gross overestimation of exposures, particularly in older subjects who smoke. (C) 1999 by Radiation Research Society. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA. Calif Pacific Med Ctr, Inst Res, San Francisco, CA 94143 USA. RP Tucker, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. FU NCI NIH HHS [CA59431] NR 27 TC 20 Z9 20 U1 0 U2 1 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 DEC PY 1999 VL 152 IS 6 BP 655 EP 664 DI 10.2307/3580261 PG 10 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 264EW UT WOS:000084168500010 PM 10581536 ER PT J AU Gerber, GB Wick, RR Watson, CR Gossner, W Kellerer, AM AF Gerber, GB Wick, RR Watson, CR Gossner, W Kellerer, AM TI The international radiobiology archives of long-term animal studies: A tool to assess risks from alpha-particle-emitting radionuclides and a possible extension to epidemiological data SO RADIATION RESEARCH LA English DT Meeting Abstract C1 European Late Effects Project Grp, Neuherberg, Germany. GSF, Inst Radiobiol, Neuherberg, Germany. Pacific NW Lab, Richland, WA USA. GSF, Inst Pathol, Neuherberg, Germany. NR 1 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 DEC PY 1999 VL 152 IS 6 SU S BP S171 EP S171 PG 1 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 265JQ UT WOS:000084240000065 ER PT J AU Rowland, RE Lucas, HF AF Rowland, RE Lucas, HF TI Causes of death of radium cases below the threshold for radium-induced malignancies SO RADIATION RESEARCH LA English DT Meeting Abstract C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 2 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 DEC PY 1999 VL 152 IS 6 SU S BP S159 EP S160 PG 2 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 265JQ UT WOS:000084240000039 ER PT J AU Stehney, AF AF Stehney, AF TI Organ distribution of thorium in thorium workers: Good agreement with new models of the International Commission on Radiological Protection SO RADIATION RESEARCH LA English DT Article; Proceedings Paper CT International Workshop on the Health Effects of Thorotrast, Radium, Radon and Other Alpha-Emitters CY JAN 20-22, 1999 CL UNIV TOKYO, TOKYO, JAPAN SP Univ Tokyo, Japanese Govt, Sci & Technol Agency HO UNIV TOKYO ID PROCESSING PLANT; MORTALITY AB Higher than environmental levels of Th-232 have been found in autopsy samples of lungs and other organs from four former employees of a thorium refinery. Working periods of the subjects ranged from 3 to 24 years, and times from end of work to death ranged from 6 to 31 years. Examination of the distribution of thorium among the organs showed that concentrations in the lung relative to pulmonary lymph nodes, bone or liver were much higher calculated from the dosimetric models in Publication 30 of the International Commission on Radiological Protection (ICRP). Much better agreement was found with more recently proposed models in Publications 68 and 69 of the ICRP, Radiation doses estimated from the amounts of thorium in the autopsy samples were compatible with health studies that found no significant difference in mortality from that of the general population of men in the U.S. (C) 1999 by Radiation Research Society. C1 Argonne Natl Lab, Environm Safety & Hlth Div, Argonne, IL 60439 USA. RP Stehney, AF (reprint author), 1132 Curtiss St, Downers Grove, IL 60515 USA. NR 16 TC 2 Z9 2 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 DEC PY 1999 VL 152 IS 6 SU S BP S110 EP S114 DI 10.2307/3580126 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 265JQ UT WOS:000084240000026 PM 10564949 ER PT J AU Lang, JC Srajer, G Wang, J Lee, PL AF Lang, JC Srajer, G Wang, J Lee, PL TI Performance of the advanced photon source 1-BM beamline optics SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SYNCHROTRON AB Bending magnet beamlines at third-generation synchrotron sources combined with well-designed optics offer unique capabilities for providing high x-ray fluxes into relatively small focal spots. This article provides a description of the x-ray optics used in the Advanced Photon Source 1-BM beamline. The performance of these optics in terms of the delivered flux ( 9 x 10(11) ph/s/100 mA at 10 keV), energy resolution [Delta E/E approximate to 1.5 x 10(-4) with Si(111)], and focusing properties (spot size approximate to 0.25x0.60 mm) is compared with that expected from ideally reflecting and shaped optics. (C) 1999 American Institute of Physics. [S0034-6748(99)03612-6]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Lang, JC (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. NR 13 TC 38 Z9 38 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 DEC PY 1999 VL 70 IS 12 BP 4457 EP 4462 DI 10.1063/1.1150096 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 262EF UT WOS:000084052100001 ER PT J AU Morozov, VA Meyer, FW AF Morozov, VA Meyer, FW TI Simultaneous energy distribution and ion fraction measurements using a linear time-of-flight analyzer with a floatable drift tube SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MASS-SPECTROMETRY; SCATTERING; SURFACE; DEPENDENCE; HYDROGEN AB A technique for simultaneous energy distribution and ion fraction measurements using a linear time-of-flight analyzer with a floatable drift tube is described. Analytical expressions for the relative collection efficiency and viewing region of the apparatus are developed as functions of the analyzed particle reduced energy and dimensionless apparatus parameters. The method was applied to studies of large-angle scattering of singly charged oxygen ions incident on Au(110), and carried out at the Oak Ridge National Laboratory's Multicharged Ion Research Facility. Energy distributions of the scattered projectiles and the negative ion fraction are presented as a function of scattered projectile energy. As a by-product of the measurements, the relative ion detection efficiency of the particle detector was reconstructed as a function of ion impact energy on the detector. (C) 1999 American Institute of Physics. [S0034-6748(99)02112-7]. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Morozov, VA (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 17 TC 22 Z9 22 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 DEC PY 1999 VL 70 IS 12 BP 4515 EP 4522 DI 10.1063/1.1150104 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 262EF UT WOS:000084052100009 ER PT J AU Anders, A MacGill, RA McVeigh, TA AF Anders, A MacGill, RA McVeigh, TA TI Efficient, compact power supply for repetitively pulsed, "triggerless" cathodic arcs SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ION SOURCES; VACUUM AB A power supply for "triggerless," repetitively pulsed cathodic arcs has been developed. It is based on a thyristor-switched, high-voltage, high-current, pulse-forming network (PFN). It can provide high pulsed currents (up to 2 kA), with duration of 600 mu s, and pulse repetition rate of up to 10 Hz. Higher repetition rates are possible at lower current. The rectangular pulse shape and amplitude are reproducible to within a few percent. Cathodic arc initiation is extremely reliable because the charging voltage is much higher than the minimum starting voltage for the triggerless arc initiation method. The energy utilization efficiency is very high by intentionally mismatching load and PFN impedances and by using an efficiency-enhancing diode; the stored energy is dissipated primarily in the arc. [S0034-6748(99)02012-2]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 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 7 TC 21 Z9 21 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 DEC PY 1999 VL 70 IS 12 BP 4532 EP 4535 DI 10.1063/1.1150106 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 262EF UT WOS:000084052100011 ER PT J AU Khang, Y Park, Y Salmeron, M Weber, ER AF Khang, Y Park, Y Salmeron, M Weber, ER TI Low temperature ultrahigh vacuum cross-sectional scanning tunneling microscope for luminescence measurements SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We have constructed a scanning tunneling microscope with simultaneous light collection capabilities in order to investigate the opto-electronic properties of semiconductors. The microscope has in situ sample cleavage mechanism for cross-sectional sample. In order to reach low temperature (4 K), we used a specially designed cryostat. The efficiency of light collection generated in the tip-surface junction was greatly improved by use of a small parabolic mirror with the tip located at its focal point. (C) 1999 American Institute of Physics. [S0034-6748(99)04912-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Khang, Y (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 12 TC 7 Z9 7 U1 3 U2 5 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 DEC PY 1999 VL 70 IS 12 BP 4595 EP 4599 DI 10.1063/1.1150118 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 262EF UT WOS:000084052100023 ER PT J AU Steinkamp, JA Keij, JF AF Steinkamp, JA Keij, JF TI Fluorescence intensity and lifetime measurement of free and particle-bound fluorophore in a sample stream by phase-sensitive flow cytometry SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MODULATION FLUOROMETRY; DEUTERIUM-OXIDE; SINGLE CELLS; LASER DIODE; MICROSCOPY; RESOLUTION; SIGNALS; DNA; FLUOROCHROMES; EMISSIONS AB We report a novel method to quantify fluorescence intensity and lifetime of free (solution) and particle-bound fluorophore in a flow stream. The technique combines flow cytometry and frequency-domain lifetime spectroscopy principles to make unique fluorescence measurements on free fluorophore and fluorophore-labeled particles. Fluorophore-labeled microspheres suspended in a fluorophore solution are analyzed as they flow through a chamber and pass across an intensity-modulated laser beam consisting of a continuous-wave (cw) direct-current (dc) and high-frequency (sine wave) excitation component. Fluorescence emission signals consisting of a dc-offset steady-state sinusoidal signal (fluorophore solution) and a sinusoidally modulated Gaussian-shaped signal pulse (fluorophore-labeled particles) are processed electronically to quantify intensities and lifetimes. The cw-excited, particle-associated fluorophore (pulse) and steady-state (dc) solution fluorescence intensity signals are measured using low-pass filtering to remove the high-frequency signal components and an ac-coupled and a gated dc amplifier to process the respective particle-bound and free fluorophore signals. The high-frequency excited, particle-bound fluorophore and free fluorophore lifetimes are individually measured using two pairs of phase-sensitive detectors to provide signals proportional to the sine and cosine of the respective phase shifts, which are ratioed to determine the respective lifetimes. The fluorescence signal intensity and lifetime detection channel outputs are displayed as frequency distribution histograms using a computer-based data acquisition system. [S0034-6748(99)00612-7]. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Cytometry Grp LS 5, Los Alamos, NM 87545 USA. RP Steinkamp, JA (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Cytometry Grp LS 5, Mail Stop M888, Los Alamos, NM 87545 USA. NR 40 TC 12 Z9 12 U1 0 U2 12 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 DEC PY 1999 VL 70 IS 12 BP 4682 EP 4688 DI 10.1063/1.1150143 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 262EF UT WOS:000084052100037 ER PT J AU Biwer, BM Butler, JP AF Biwer, BM Butler, JP TI Vehicle emission unit risk factors for transportation risk assessments SO RISK ANALYSIS LA English DT Article DE risk assessment; transportation risk; diesel exhaust; fugitive dust; vehicle emissions ID PARTICULATE AIR-POLLUTION; MORTALITY; STATES; RESUSPENSION AB When the transportation risk posed by shipments of hazardous chemical and radioactive materials is being assessed, it is necessary to evaluate the risks associated with both vehicle emissions and cargo-related risks. Diesel exhaust and fugitive dust emissions from vehicles transporting hazardous shipments lead to increased air pollution, which increases the risk of latent fatalities in the affected population along the transport route. The estimated risk from these vehicle-related sources can often be as large or larger than the estimated risk associated with the material being transported. In this paper, data from the U.S. Environmental Protection Agency's Motor Vehicle-Related Air Toxics Study are first used to develop latent cancer fatality estimates per kilometer of travel in rural and urban areas for all diesel truck classes. These unit risk factors are based on studies investigating the carcinogenic nature of diesel exhaust. With the same methodology, the current per-kilometer latent fatality risk factor used in transportation risk assessments for heavy diesel trucks in urban areas is revised and the analysis expanded to provide risk factors for rural areas and all diesel truck classes, These latter fatality estimates may include, but are not limited to, cancer fatalities and are based primarily on the most recent epidemiological data available on mortality rates associated with ambient air PM-10 concentrations. C1 Argonne Natl Lab, Environm Assessment Div, Argonne, IL 60439 USA. RP Biwer, BM (reprint author), Argonne Natl Lab, Environm Assessment Div, Argonne, IL 60439 USA. NR 40 TC 4 Z9 4 U1 0 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD DEC PY 1999 VL 19 IS 6 BP 1157 EP 1171 PG 15 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 266HZ UT WOS:000084295700011 PM 10765454 ER PT J AU Hertwich, EG McKone, TE Pease, WS AF Hertwich, EG McKone, TE Pease, WS TI Parameter uncertainty and variability in evaluative fate and exposure models SO RISK ANALYSIS LA English DT Article DE multimedia modeling; uncertainty; variability; exposure efficiency; toxicity scoring; toxics release inventory (TRI); life cycle assessment (LCA) ID FUGACITY MODEL; AIR AB The human toxicity potential, a weighting scheme used to evaluate toxic emissions for life cycle assessment and toxics release inventories, is based on potential dose calculations and toxicity factors. This paper evaluates the variance in potential dose calculations that can be attributed to the uncertainty in chemical-specific input parameters as well as the variability in exposure factors and landscape parameters. A knowledge of the uncertainty allows us to assess the robustness of a decision based on the toxicity potential; a knowledge of the sources of uncertainty allows us to focus our resources if we want to reduce the uncertainty. The potential dose of 236 chemicals was assessed. The chemicals were grouped by dominant exposure route, and a Monte Carlo analysis was conducted for one representative chemical in each group. The variance is typically one to two orders of magnitude. For comparison, the point estimates in potential dose for 236 chemicals span ten orders of magnitude. Most of the variance in the potential dose is due to chemical-specific input parameters, especially half-lives, although exposure factors such as fish intake and the source of drinking water can be important for chemicals whose dominant exposure is through indirect routes, Landscape characteristics are generally of minor importance. C1 Univ Calif Berkeley, Energy & Resources Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Environm Defense Fund, Oakland, CA 94618 USA. RP Hertwich, EG (reprint author), Univ Calif Berkeley, Energy & Resources Grp, Berkeley, CA 94720 USA. OI Hertwich, Edgar/0000-0002-4934-3421 NR 37 TC 64 Z9 65 U1 0 U2 17 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD DEC PY 1999 VL 19 IS 6 BP 1193 EP 1204 DI 10.1023/A:1007094930671 PG 12 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 266HZ UT WOS:000084295700014 PM 10765456 ER PT J AU Silverman, KS Zheng, MX Wu, M Tinoco, I Cech, TR AF Silverman, KS Zheng, MX Wu, M Tinoco, I Cech, TR TI Quantifying the energetic interplay of RNA tertiary and secondary structure interactions SO RNA-A PUBLICATION OF THE RNA SOCIETY LA English DT Article DE DMS modification; NMR; nondenaturing gel electrophoresis; P4-P6; P5abc; secondary structure rearrangement; tP5abc ID TETRAHYMENA RIBOZYME; DOMAIN; INTRON; NMR AB To understand the RNA-folding problem, we must know the extent to which RNA structure formation is hierarchical (tertiary folding of preformed secondary structure). Recently, nuclear magnetic resonance (NMR) spectroscopy was used to show that Mg(2+)-dependent tertiary interactions force secondary structure rearrangement in the 56-nt tP5abc RNA, a truncated subdomain of the Tetrahymena group I intron. Here we combine mutagenesis with folding computations, nondenaturing gel electrophoresis, high-resolution NMR spectroscopy, and chemical-modification experiments to probe further the energetic interplay of tertiary and secondary interactions in tP5abc, Point mutations predicted to destabilize the secondary structure of folded tP5abc greatly disrupt its Mg(2+)-dependent folding, as monitored by nondenaturing gels. Imino proton assignments and sequential NOE walks of the two-dimensional NMR spectrum of one of the tP5abc mutants confirm the predicted secondary structure, which does not change in the presence of Mg(2+), In contrast to these data on tP5abc, the same point mutations in the context of the P4-P6 domain (of which P5abc is a subdomain) shift the Mg(2+) dependence of P4-P6 folding only moderately, and dimethyl sulfate (DMS) modification experiments demonstrate that Mg(2+) does cause secondary structure rearrangement of the P4-P6 mutants' P5abc subdomains. Our data provide experimental support for two simple conclusions: (1) Even single point mutations at bases involved only in secondary structure can be enough to tip the balance between RNA tertiary and secondary interactions. (2) Domain context must be considered in evaluating the relative importance of tertiary and secondary contributions. This tertiary/secondary interplay is likely relevant to the folding of many large RNA and to bimolecular snRNA-snRNA and snRNA-intron RNA interactions. C1 Univ Colorado, Dept Chem & Biochem, Howard Hughes Med Inst, Boulder, CO 80309 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Phys Biosci Div, Dept Biol Struct, Berkeley, CA 94720 USA. RP Silverman, KS (reprint author), Univ Colorado, Dept Chem & Biochem, Howard Hughes Med Inst, Campus Box 215, Boulder, CO 80309 USA. EM Scott.Silverman@colorado.edu NR 24 TC 21 Z9 21 U1 1 U2 6 PU COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT PI COLD SPRING HARBOR PA 1 BUNGTOWN RD, COLD SPRING HARBOR, NY 11724 USA SN 1355-8382 J9 RNA JI RNA-Publ. RNA Soc. PD DEC PY 1999 VL 5 IS 12 BP 1665 EP 1674 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263JR UT WOS:000084122000014 ER PT J AU Sincell, MW Gehmeyr, M Mihalas, D AF Sincell, MW Gehmeyr, M Mihalas, D TI The quasi-stationary structure of radiating shock waves. I. The one-temperature fluid SO SHOCK WAVES LA English DT Article DE radiating shock waves; supercritical shocks; subcritical shocks; adaptive grid; numerical methods ID HYDRODYNAMICS AB We calculate the quasi-stationary structure of a radiating shock wave propagating through a spherically symmetric shell of cold gas by solving the time-dependent equations of radiation hydrodynamics on an implicit adaptive grid. We show that this code successfully resolves the shock wave in both the subcritical and supercritical cases and, for the first time; we have reproduced all the expected features including the optically thin temperature spike at a supercritical shock front - without invoking analytic jump conditions at the discontinuity. We solve the full moment equations for the radiation flux and energy density, but the shock wave structure can also be reproduced if the radiation flux is assumed to be proportional to the gradient of the energy density (the diffusion approximation), as long as the radiation energy density is determined by the appropriate radiative transfer moment equation. We find that Zel'dovich and Raizer's (1967) analytic solution for the shock wave structure accurately describes a subcritical shock but it underestimates the gas temperature, pressure, and the radiation flux in the gas ahead of a supercritical shock. We argue that this discrepancy is a consequence of neglecting terms which are second order in the minimum inverse shock compression ratio [eta(1) = (gamma - 1)/(gamma + 1), where gamma is the adiabatic index] and the inaccurate treatment of radiative transfer near the discontinuity. In addition, we verify that the maximum temperature of the gas immediately behind the shock is gives by T+ = 4T(1)/(gamma + 1); where T-1 is the gas temperature far behind the shock. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Lab Computat Astrophys, Urbana, IL 61801 USA. RP Mihalas, D (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Grp XTM MSD409, POB 1663, Los Alamos, NM 87545 USA. NR 9 TC 20 Z9 20 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD DEC PY 1999 VL 9 IS 6 BP 391 EP 402 DI 10.1007/s001930050169 PG 12 WC Mechanics SC Mechanics GA 273QC UT WOS:000084717500003 ER PT J AU Sincell, MW Gehmeyr, M Mihalas, D AF Sincell, MW Gehmeyr, M Mihalas, D TI The quasi-stationary structure of radiating shock waves. II. The two-temperature fluid SO SHOCK WAVES LA English DT Article DE radiating shock waves; numerical methods AB We solve the equations of radiation hydrodynamics in the two-temperature fluid approximation on an adaptive grid. The temperature structure depends upon the electron-ion energy exchange length, l(ei), and the election conduction length, I-ec. Three types of radiating shock structure are observed: subcritical, where preheating of the unshocked gas is negligible; electron supercritical, where radiation preheating raises the temperature of the unshocked electron fluid to be equal to the final electron temperature; supercritical, ii here preheating and electron-ion energy exchange raise the preshock T-e,T-i to their final post shock values. No supercritical shock develops when l(ei) is larger than the photospheric depth of the shocked gas because a negligible amount of the ion energy is transferred to the electrons and the shock is weakly radiating. Electron conduction smooths the T-e profile on a length scale l(ec), reducing the radiation flux. C1 Observ Paris Meudon, Dept Astrophys Extragalact & Cosmol, Meudon, France. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Lab Computat Astrophys, Urbana, IL 61801 USA. RP Mihalas, D (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Grp XTM MSD409, POB 1663, Los Alamos, NM 87545 USA. NR 10 TC 7 Z9 7 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD DEC PY 1999 VL 9 IS 6 BP 403 EP 411 DI 10.1007/s001930050170 PG 9 WC Mechanics SC Mechanics GA 273QC UT WOS:000084717500004 ER PT J AU Du, Q Faber, V Gunzburger, M AF Du, Q Faber, V Gunzburger, M TI Centroidal Voronoi tessellations: Applications and algorithms SO SIAM REVIEW LA English DT Article DE Voronoi tessellations; centroids; vector quantization; data compression; clustering ID EXPLORATORY PROJECTION PURSUIT; GEOMETRICAL MODELS; OPTIMAL QUANTIZER; THEOREM; DESIGN; APPROXIMATION; CONVERGENCE; TERRITORIES; EFFICIENT; INTEGRALS AB A centroidal Voronoi tessellation is a Voronoi tessellation whose generating points are the centroids (centers of mass) of the corresponding Voronoi regions. We give some applications of such tessellations to problems in image compression, quadrature, finite difference methods, distribution of resources, cellular biology, statistics, and the territorial behavior of animals. We discuss methods for computing these tessellations, provide some analyses concerning both the tessellations and the methods for their determination, and, finally, present the results of some numerical experiments. C1 Iowa State Univ, Dept Math, Ames, IA 50011 USA. Hong Kong Univ Sci & Technol, Kowloon, Hong Kong. Univ Calif Los Alamos Natl Lab, Commun & Comp Div, Los Alamos, NM 87545 USA. RP Du, Q (reprint author), Iowa State Univ, Dept Math, Ames, IA 50011 USA. RI Du, Qiang/B-1021-2008 OI Du, Qiang/0000-0002-1067-8937 NR 64 TC 715 Z9 751 U1 5 U2 50 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD DEC PY 1999 VL 41 IS 4 BP 637 EP 676 DI 10.1137/S0036144599352836 PG 40 WC Mathematics, Applied SC Mathematics GA 262XY UT WOS:000084094600002 ER PT J AU Zhang, DX Tchelepi, H AF Zhang, Dongxiao Tchelepi, Hamdi TI Stochastic Analysis of Immiscible Two-Phase Flow in Heterogeneous Media SO SPE JOURNAL LA English DT Article AB We present a stochastic analysis of immiscible two-phase flow (Buckley-Leverett displacement) in heterogeneous reservoirs. Since the detailed spatial variabilities of reservoir properties such as permeability and porosity cannot be described deterministically, both permeability and porosity, or either, are treated as random space functions. In turn, water saturation and oil production rate are also random variables. The main purpose of this study is to estimate the saturation field (by its expected value) and the associated uncertainty (by its standard deviation) for Buckley-Leverett displacement in such random media. The expected value and standard deviation may be used to construct confidence intervals for the saturation field in a reservoir and to evaluate the risk associated with a project caused by the incomplete knowledge of reservoir properties. Through transforming to coordinates attached to streamlines, the evaluation of saturation statistical moments is simplified to that of travel time and transverse displacement probability density functions. The latter do not vary with the two-phase composition but entirely depend on the total velocity under some conditions. Through some one-and two-dimensional examples, we found that the well-known discontinuities existing in saturation profiles and oil production curves for homogeneous media disappear in the case of heterogeneous media. This is due to heterogeneity fingering, or the so-called "heterogeneity induced dispersion." The effect of heterogeneity on oil production is the earlier water breakthrough and later oil arrival. The oil production is expected to take longer in heterogeneous media than in homogeneous media. C1 [Zhang, Dongxiao] Los Alamos Natl Lab, Los Alamos, NM 87545 USA. [Tchelepi, Hamdi] Chevron Petr Technol Co, La Habra, CA USA. RP Zhang, DX (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM dzhang@vega.lanl.gov; jhamt@chevron.com RI Zhang, Dongxiao/D-5289-2009 OI Zhang, Dongxiao/0000-0001-6930-5994 FU U.S. Dept. of Energy [97528] FX This work was partially funded by LDRD Project No. 97528 from Los Alamos Natl. Laboratory, which is operated by the U. of California for the U.S. Dept. of Energy. The authors wish to thank Dr. Liyong Li for making comparisons of the approach presented in this paper with Monte Carlo simulations and providing Fig. 5 to us. We also want to thank the two anonymous reviewers for their helpful comments on this paper. NR 39 TC 20 Z9 21 U1 0 U2 1 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR,, RICHARDSON, TX 75080 USA SN 1086-055X EI 1930-0220 J9 SPE J JI SPE J. PD DEC PY 1999 VL 4 IS 4 BP 380 EP 388 PG 9 WC Engineering, Petroleum SC Engineering GA V33KF UT WOS:000209017000011 ER PT J AU Vasco, DW Yoon, S Datta-Gupta, A AF Vasco, D. W. Yoon, Seongsik Datta-Gupta, Akhil TI Integrating Dynamic Data Into High-Resolution Reservoir Models Using Streamline-Based Analytic Sensitivity Coefficients SO SPE JOURNAL LA English DT Article AB One of the outstanding challenges in reservoir characterization is to build high-resolution reservoir models that satisfy static as well as dynamic data. However, integration of dynamic data typically requires the solution of an inverse problem that can be computationally intensive and becomes practically infeasible for fine-scale reservoir models. A critical issue here is computation of sensitivity coefficients, the derivatives of dynamic production history with respect to model parameters such as permeability and porosity. We propose a new analytic technique that has several advantages over existing approaches. First, the method utilizes an extremely efficient three-dimensional multiphase streamline simulator as a forward model. Second, the parameter sensitivities are formulated in terms of one-dimensional integrals of analytic functions along the streamlines. Thus, the computation of sensitivities for all model parameters requires only a single simulation run to construct the velocity field and generate the streamlines. The integration of dynamic data is then performed using a two-step iterative inversion that involves (i) "lining up" the breakthrough times at the producing wells and then (ii) matching the production history. Our approach follows from an analogy between streamlines and ray tracing in seismology. The inverse method is analogous to seismic waveform inversion and thus, allows us to utilize efficient methods from geophysical imaging. We have applied the proposed approach to a highly heterogeneous carbonate reservoir in west Texas. The reservoir model consists of 50,000 cells and includes multiple patterns with 42 wells. Water-cut histories from 27 producing wells are utilized to characterize porosity and permeability distribution in the reservoir, a total of 100,000 parameters. C1 [Vasco, D. W.] Lawrence Berkeley Natl Lab, Berkeley, CA 94704 USA. [Yoon, Seongsik] Texas A&M U, College Stn, TX USA. [Datta-Gupta, Akhil] Texas A&M U, Dept Petr Engn, College Stn, TX USA. RP Vasco, DW (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94704 USA. EM ssyoon@tamu.edu; datta-gupta@tamu.edu RI Vasco, Donald/I-3167-2016 OI Vasco, Donald/0000-0003-1210-8628 FU Office of Oil Gas and Shale Technologies, of the U.S. Dept. of Energy [DE-AC03-76SF00098] FX Akhil Datta-Gupta and Seongsik Yoon would like to acknowledge the financial support of the industrial sponsors of the Joint Industry Project on integrated reservoir description. Don Vasco was supported by the Assistant Secretary for Fossil Energy, Office of Oil Gas and Shale Technologies, of the U.S. Dept. of Energy under contract No. DE-AC03-76SF00098. NR 27 TC 46 Z9 46 U1 0 U2 1 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR,, RICHARDSON, TX 75080 USA SN 1086-055X EI 1930-0220 J9 SPE J JI SPE J. PD DEC PY 1999 VL 4 IS 4 BP 389 EP 399 DI 10.2118/59253-PA PG 11 WC Engineering, Petroleum SC Engineering GA V33KF UT WOS:000209017000012 ER PT J AU Schilling, CH Tomasik, P Kim, JC AF Schilling, CH Tomasik, P Kim, JC TI Processing technical ceramics with maltodextrins: Crosslinking by acetalation SO STARCH-STARKE LA English DT Article; Proceedings Paper CT 50th Starch Convention of the Association-of-Cereal-Research CY APR 21-23, 1999 CL DETMOLD, GERMANY SP Assoc Cereal Res ID INJECTION-MOLDING PROCESS; ALUMINA AB Technical ceramics are made by a sequential process of: (i) mixing ceramic powder with an organic carrier liquid (e.g.. organic solvents, polyethylene wax) to form a plastic slurry, (ii) molding the plastic slurry into a three-dimensional shape, (iii) thermal treatment to evaporate or pyrolyze the organic carrier, and (iv) kiln firing. In this paper, the use of aqueous polysaccharide solutions is examined as environmentally-friendly, economically-viable substitutes for organic carrier liquids in ceramic molding. The central focus of the present study is to examine optimum conditions for crosslinking model slurries of maltodextrin and colloidal aluminum oxide by acetalation of maltodextrin. Crosslinking is needed to prevent the common problem of cracks that form in ceramic shapes during thermal treatment (stage iii above). Experiments involving rheology and differential thermal analysis revealed that glyoxal and glutaraldehyde are effective crosslinkers, whereas formaldehyde and pyruvic acid did not exhibit measureable changes in slurry rheology over a wide range of concentrations. Glutaraldehyde reacted faster than glyoxal, however, glyoxal produced the strongest gels. Basic conditions catalyzed acetalation. The sequence of blending the slurry components had no significant effect on slurry rheology. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Univ Agr, Dept Chem, PL-31120 Krakow, Poland. Hanyang Univ, Ceram Mat Res Inst, Seoul 133791, South Korea. RP Schilling, CH (reprint author), Iowa State Univ, Ames Lab, Gilman Hall, Ames, IA 50011 USA. NR 20 TC 11 Z9 12 U1 1 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0038-9056 J9 STARCH-STARKE JI Starch-Starke PD DEC PY 1999 VL 51 IS 11-12 BP 397 EP 405 DI 10.1002/(SICI)1521-379X(199912)51:11/12<397::AID-STAR397>3.0.CO;2-L PG 9 WC Food Science & Technology SC Food Science & Technology GA 285WR UT WOS:000085411800003 ER PT J AU Li, Q Tsay, YN Zhu, Y Suenaga, M Gu, GD Koshizuka, N AF Li, Q Tsay, YN Zhu, Y Suenaga, M Gu, GD Koshizuka, N TI Supercurrent transport across [001] twist grain boundaries in Bi2Sr2CaCu2O8+delta bicrystals SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article; Proceedings Paper CT 9th International Workshop on Critical Currents in Superconductors (IWCC 9) CY JUL 07-10, 1999 CL UNIV WISCONSIN, MADISON, WISCONSIN HO UNIV WISCONSIN ID SUPERCONDUCTOR AB A series of 35 bulk Bi2Sr2CaCu2O8+delta (Bi2212) bicrystals containing a single high-quality [001] twist grain boundary was prepared in order to investigate the supercurrent transport mechanism in textured Pi-based superconducting tape. The misorientation angles of the bicrystals ranged from 0 to 180 degrees. These twist grain boundaries carried critical current as high as their constituent single crystals, regardless of the misorientation angle. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. ISTEC, Superconduct Res Lab, Koto Ku, Tokyo 135, Japan. RP Li, Q (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NR 12 TC 9 Z9 9 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 DEC PY 1999 VL 12 IS 12 BP 1046 EP 1049 DI 10.1088/0953-2048/12/12/302 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 264UG UT WOS:000084200400002 ER PT J AU Lee, GD Wang, CZ Lu, ZY Ho, KM AF Lee, GD Wang, CZ Lu, ZY Ho, KM TI Addimer diffusion on the Si(100) surface SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID SI AD-DIMERS; SI(001); DYNAMICS; NUCLEATION; BINDING; MODEL AB Diffusion of silicon addimer along the trough and from the trough to the top of dimer row on the Si(100) surface are investigated by tight-binding molecular dynamics calculations using the environment-dependent tight-binding silicon potential and by ab initio calculations using the Car-Parrinello method. The studies discover new diffusion pathways consisting of rotation of addimer. These new pathways have energy barriers in excellent agreement with experiment data and are more energetically favorable than other diffusion pathways studied previously. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Wang, CZ (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI 上官, 敏慧/E-8964-2012; Lee, Gun-Do/L-1259-2013 OI Lee, Gun-Do/0000-0001-8328-8625 NR 20 TC 1 Z9 1 U1 1 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1015 EP 1023 DI 10.1142/S0218625X99001098 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100008 ER PT J AU Wang, CZ Ho, KM AF Wang, CZ Ho, KM TI Atomistic simulation of laser ablation of diamond and silicon (111) surface SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID SI; TRANSITIONS; DYNAMICS; DISORDER; GAAS AB Tight-binding molecular dynamics simulations are performed to study femtosecond-laser ablation of diamond and silicon (111) surface. The simulation results show that under intense ultrafast laser ablation the diamond (111) surface graphitizes while the silicon (111) surface melts spontaneously. All structural changes occur within a few hundred femtoseconds, which is much shorter than the typical lattice dynamics time scale, in consistent with experimental observations. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Wang, CZ (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 16 TC 1 Z9 1 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1025 EP 1030 DI 10.1142/S0218625X99001104 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100009 ER PT J AU Kim, KH Kang, JS Olson, CG AF Kim, KH Kang, JS Olson, CG TI The growth and electronic structures of epitaxial CrSi2 films prepared on Si(111) substrate SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID THIN-FILMS; SI-CR; GAP; DISILICIDES; SILICIDES AB Highly epitaxial CrSi2 films were grown on Si(111) substrate by Cr deposition on Si(111)-(7 x 7) surface at 450 degrees C followed by in situ annealing at 900-1100 degrees C in ultrahigh vacuum. CrSi2(001) plane was grown parallel to the Si(111) plane with a CrSi2[210]//Si[110] matching face relationship. The valence band (VB) photoemission for the 1200-Angstrom-thick CrSi2 was measured at room temperature and 20 K by using synchrotron radiation (h nu = 20-120 eV). Overall shapes of the two energy distribution curves (EDC's) were similar. Two peaks were observed in the EDC's corresponding to the bonding and the nonbonding Cr-d states in the CrSi2. The onset of the VB photoemission measured at 20 K was located at about 0.32 eV below Fermi level, due to the energy band gap opening at low temperature. C1 Gyeongsang Natl Univ, Dept Phys, Chinju 660701, South Korea. Catholic Univ Korea, Dept Phys, Pucheon 422743, South Korea. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Kim, KH (reprint author), Gyeongsang Natl Univ, Dept Phys, Chinju 660701, South Korea. NR 23 TC 2 Z9 2 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1103 EP 1108 DI 10.1142/S0218625X99001220 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100021 ER PT J AU Pizzagalli, L Catellani, A Galli, G Gygi, F Baratoff, A AF Pizzagalli, L Catellani, A Galli, G Gygi, F Baratoff, A TI Theoretical study of Si and N adsorption on the Si-terminated SiC(001) surface SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID FIRST-PRINCIPLES CALCULATIONS; BETA-SIC(100) SURFACE; EPITAXIAL-GROWTH; ATOMIC-STRUCTURE; MOLECULAR-DYNAMICS; THIN-FILMS; AB-INITIO; RECONSTRUCTION; NITROGEN; NITRIDE AB We report the results of first principles molecular dynamics simulations of the adsorption of Si and N atoms on a Si-terminated p(2 x 1) SiC(001) surface. In particular, we discuss different structural models for the Si-rich (3 x 2) surface, and the adsorption of 1/8, 1/2 and 1 monolayer nitrogen on the p(2 x 1) surface. Our simulations show that a SiC(001)-p(2 x 1) surface covered by a nitrogen monolayer is an inert substrate which inhibits growth. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. CNR, MASPEC, I-43100 Parma, Italy. Univ Basel, Dept Phys & Astron, CH-4056 Basel, Switzerland. RP Pizzagalli, L (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-415, Livermore, CA 94550 USA. RI Pizzagalli, Laurent/A-1445-2013; OI Catellani, Alessandra/0000-0001-5197-7186 NR 47 TC 1 Z9 1 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1143 EP 1150 DI 10.1142/S0218625X99001268 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100025 ER PT J AU Carrier, X Doyle, CS Kendelewicz, T Brown, GE AF Carrier, X Doyle, CS Kendelewicz, T Brown, GE TI Reaction of CO2 with MgO(100) surfaces SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID CARBON-DIOXIDE; METAL-OXIDES; PROBE MOLECULES; MGO SURFACES; ADSORPTION; CHEMISORPTION; ORIENTATION; CHEMISTRY; BASICITY; FORMATE AB Synchrotron-based photoemission spectroscopy (C 1s and O 1s regions) as well as C K-edge NEXAFS spectroscopy have been used to investigate the formation of carbonate species on the surface of MgO(100) after exposure to CO2 at pressures ranging from 0.8 to 260 Torr. These results are tentatively compared with a two-stage model for the reaction of H2O on MgO(100) [Liu et al., Surf. Sci. 412/413, 287 (1998)]. At p(CO2) values below a threshold pressure (predicted to be in the range of 10(-9)-10(-6) Torr), the reaction of CO2 with MgO(100) is fairly limited and CO2 is assumed to react with defect sites only. At pressures greater than or equal to 0.8 Torr, CO2 reacts with terrace sites, resulting in extensive formation of CO32- groups on the MgO(100) surface. However, carbonate formed at "high" pressures (P-CO2 greater than or equal to 0 0.8 Torr) begins to desorb at the low pressure of the analysis chamber (10-11 Torr), which is consistent with equilibrium thermodynamic predictions of the "threshold" pressure for the reaction MgO + CO2 = MgCO3.(.) Results from polarization-dependent C K-edge NEXAFS spectroscopy suggest that the carbonate molecules formed on the surface are structurally disordered. The chemical nature of adventitious carbon formed on the MgO(100) surface was also investigated, and is clearly different from CO32-. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Carrier, X (reprint author), Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. RI Carrier, Xavier/A-4405-2015 OI Carrier, Xavier/0000-0002-5440-4559 NR 34 TC 18 Z9 18 U1 0 U2 16 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1237 EP 1245 DI 10.1142/S0218625X99001396 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100038 ER PT J AU Doyle, CS Kendelewicz, T Carrier, X Brown, GE AF Doyle, CS Kendelewicz, T Carrier, X Brown, GE TI The interaction of carbon dioxide with single crystal CaO(100) surfaces SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID X-RAY PHOTOELECTRON; XPS; SPECTROSCOPY; ORIENTATION; CALCITE; CA AB We have carried out synchrotron-based photoemission spectroscopy (O 1s, C 1s, Ca 2p, Ca 3p/O 2s/VB) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy (C K-edge) study of the interaction of CO2 with UHV-cleaved synthetic single crystal CaO(100) surfaces. Our data are compared with data collected from a high quality natural sample of CaCO3(<10(1)over bar 4>) (calcite). The CaO (100) surface readily undergoes hydroxylation with the ambient p(H2O) associated with most UHV systems. Carbon coverages were observed to be lower for the most hydroxylated sample. Comparison of our C K-edge data for CO2/CaO(100) and calcite indicates that there is formation of a surface carbonate species at CO2 pressures above 10(-6) Torr. The reaction of CaO(100) with CO2 occurs at far lower CO2 Pressures than for MgO(100), which is consistent with equilibrium thermodynamic predictions. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Doyle, CS (reprint author), Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. RI Carrier, Xavier/A-4405-2015 OI Carrier, Xavier/0000-0002-5440-4559 NR 17 TC 21 Z9 21 U1 2 U2 27 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1247 EP 1254 DI 10.1142/S0218625X99001403 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100039 ER PT J AU Kendelewicz, T Doyle, CS Carrier, X Brown, GE AF Kendelewicz, T Doyle, CS Carrier, X Brown, GE TI Reaction of water with clean surfaces of MnO(100) SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID PHOTOEMISSION AB Water adsorption on the MnO(100) single crystal surface was quantitatively monitored using chemical shifts in the O 1s core level spectra. We find that the initial reactions at low water vapor pressures of 10(-8)-10(-4) Torr are limited to a small fraction of a monolayer and involve dissociation of water at or near defect centers resulting in surface hydroxyls. Even at these low pressures, there is an increase in water adsorption with increasing dosing time. Water uptake increases dramatically for vapor pressures between 10(-4) and 10(-2) Torr and then stabilizes above 10(-2) Torr. At this pressure, hydroxyl coverages slightly exceed a monolayer. Hydroxyl species formed on this surface are unstable and can be removed by annealing to 200 degrees C. These data are compared with those from similar studies of the interaction of water vapor with MgO(100) and the surfaces of iron oxides (alpha-Fe2O3 and Fe3O4), and some quantitative similarities and differences are discussed. In particular, the role of cooperative interactions in the condensed water overlayer in surface hydroxylation is emphasized. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Kendelewicz, T (reprint author), Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. RI Carrier, Xavier/A-4405-2015 OI Carrier, Xavier/0000-0002-5440-4559 NR 20 TC 8 Z9 8 U1 2 U2 7 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1255 EP 1263 DI 10.1142/S0218625X99001414 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100040 ER PT J AU Salmeron, M Bluhm, H AF Salmeron, M Bluhm, H TI Structure and properties of ice and water film interfaces in equilibrium with vapor SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia, Amer Vacuum Soc, Pacific NW Chapter, US DOE, Canadian Soc Chem, Div Surfaces Sci, Canadian Assoc Phys, Div Surfaces Sci, ELMITEC, Elsevier Sci, Int Union Pure & Appl Phys, Leybold, NRC, Natl Vacuum Technol, OCI, Vacuum Microengn, OMICRON, Phys Electr, SPECS, VG Sci HO UNIV BRITISH COLUMBIA ID POLARIZATION FORCE MICROSCOPY; SURFACE; SPECTROSCOPY; MICA C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 16 TC 10 Z9 10 U1 1 U2 4 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD DEC PY 1999 VL 6 IS 6 BP 1275 EP 1281 DI 10.1142/S0218625X99001438 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 305TU UT WOS:000086557100042 ER PT J AU Rodriguez, JA Jirsak, T Chaturvedi, S Kuhn, M AF Rodriguez, JA Jirsak, T Chaturvedi, S Kuhn, M TI Reaction of SO2 with ZnO(000(1)over-bar)-O and ZnO powders: photoemission and XANES studies on the formation of SO3 and SO4 SO SURFACE SCIENCE LA English DT Article DE alkali metals; photoelectron spectroscopy; single crystal surfaces; sulfur; sulphur dioxide; surface chemical reaction; X-ray absorption spectroscopy; zinc oxide ID SURFACE ELECTRONIC-STRUCTURE; TRANSITION-METAL SURFACES; OXIDE SURFACES; SULFUR-DIOXIDE; ADSORPTION; CHEMISTRY; FILMS; CS; CU; CHEMISORPTION AB Synchrotron-based high-resolution photoemission and X-ray absortion near-edge spectroscopy (XANES) have been used to study the interaction of SO2 with ZnO(000 (1) over bar)-O and polycrystalline films and bulk powders of ZnO. The adsorption of SO2 on the (000 (1) over bar) oxygen-terminated face of ZnO at 110 K produced SO3 species which were stable up to temperatures well above 400 K. On polycrystalline ZnO, the Zn<->SO2 interactions were very weak, there was no decomposition of the admolecule, and evidence for bonding of zinc to SO2 was found only at low temperatures (similar to 100 K) when the adsorbate had a limited mobility on the surface. At 300 K and moderate pressures, SO2 only reacted with the oxygen centers of ZnO forming mainly SO3 groups. Part of the formed SO3 decomposed at temperatures between 400 and 600 K with evolution of SO2 into the gas phase (ZnSO3,solid-->SO2,gas + ZnOsolid). At 600 K, a significant amount of SO2 was still present on the ZnO systems. Reaction with O-2 led to an SO3-->SO4 transformation on ZnO(000 (1) over bar)-O and powders of ZnO previously exposed to SO2. SO4 was directly formed during the adsorption of SO2 on polycrystalline surfaces of zinc oxide that were rich in oxygen atoms which had a low coordination number (<3) and a relatively high mobility. On ZnO(000 (1) over bar)-O and polycrystalline ZnO, there was no decomposition of sulfur dioxide. Promotion with potassium and cesium facilitated the cleavage of S-O bonds. After dosing SO2 to (root 3 x root 3)-K/ZnO(000 (1) over bar)-O and (root 3 x root 3)-Cs/ZnO(000 (1) over bar)-O at 300 K, several sulfur species (S, SO3, SO4) coexisted on the alkali-metal-promoted surfaces whereas only SO3 was formed on the pure ZnO(000 (1) over bar)-O system. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 55 TC 56 Z9 56 U1 3 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 1 PY 1999 VL 442 IS 3 BP 400 EP 412 DI 10.1016/S0039-6028(99)00952-8 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 260ZD UT WOS:000083982600010 ER PT J AU Mormile, MR Romine, MF Garcia, T Ventosa, A Bailey, TJ Peyton, BM AF Mormile, MR Romine, MF Garcia, T Ventosa, A Bailey, TJ Peyton, BM TI Halomonas campisalis sp nov., a denitrifying, moderately haloalkaliphilic bacterium SO SYSTEMATIC AND APPLIED MICROBIOLOGY LA English DT Article DE Halomonas campisalis sp nov.; moderate halophile; alkaliphile; denitrification; ion exchange ID BIOLOGICAL TREATMENT; WASTE-WATER; ALKALIPHILES; DIVERSITY AB The isolation and characterization of a denitrifying bacterium that is both moderately halophilic and alkaliphilic is described. The organism was isolated for use in the development of a bioprocess that could potentially reduce the costs of ion exchange resin regenerant disposal. The process of ion exchange, after resin regeneration, produces a briny, alkaline waste that is difficult and expensive to dispose. The biological removal of nitrate and subsequent reuse of these brines can potentially provide a cost-saving alternative to disposing of this waste product. To achieve our objective, a moderately halophilic, alkaliphilic bacterium was isolated from sediment samples taken from the salt plain of Alkali Lake in Washington State (USA). The haloalkaliphilic bacterium, designated strain 4A, is motile with rod-shaped cells that are 3 to 5 mu m long and 1 mu m wide. Electron accepters used include oxygen, nitrate, and nitrite. In addition, it has similar specific nitrate reduction rates and biomass yields as non-halophilic denitrifying bacteria. It is capable of using a variety of electron donors. This organism can grow at NaCl concentrations ranging from 0.2 to 4.5 M with optimum growth occurring at 1.5 M and pH values ranging from 6 to 12 with 9.5 being the optimum pH. The temperature range for growth of strain 4A is 4-50 degrees C with optimal growth occurring at 30 degrees C. The G + C content is 66 mol%. Phylogenetic analyses based upon 16S rDNA gene sequence placed isolate 4A in the genus Halomonas. In addition, DNA-DNA hybridization experiments clearly indicate that it is a unique species. Phenotypic and phylogenetic studies indicate that isolate 4A represents a new species. We propose the name Halomonas campisalis for this species and strain 4A (ATCC 700597) as the type strain. Due to its denitrification ability, broad carbon utilization range and its high salinity and pH tolerance this organism, and similar ones, hold promise for the treatment of saline, alkaline waste. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Seville, Fac Pharm, Dept Microbiol & Parasitol, Seville, Spain. Washington State Univ, Dept Chem Engn, Pullman, WA USA. RP Mormile, MR (reprint author), Univ Missouri, Dept Biol Sci, Rolla, MO 65401 USA. RI GARCIA GUTIERREZ, MARIA TERESA /K-6515-2014; OI GARCIA GUTIERREZ, MARIA TERESA /0000-0002-0916-6256; Mormile, Melanie/0000-0001-9054-2687; Peyton, Brent/0000-0003-0033-0651 NR 30 TC 89 Z9 93 U1 2 U2 16 PU GUSTAV FISCHER VERLAG PI JENA PA VILLENGANG 2, D-07745 JENA, GERMANY SN 0723-2020 J9 SYST APPL MICROBIOL JI Syst. Appl. Microbiol. PD DEC PY 1999 VL 22 IS 4 BP 551 EP 558 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 286JV UT WOS:000085441000008 PM 10794143 ER PT J AU Dimmel, DR Althen, E Savidakis, M Courchene, C Bozell, JJ AF Dimmel, DR Althen, E Savidakis, M Courchene, C Bozell, JJ TI New quinone-based pulping catalysts SO TAPPI JOURNAL LA English DT Article ID NITROGEN-DIOXIDE OXIDATION; LIGNIN-DERIVED QUINONES; BENZOQUINONES AB 2,617-Dimethylanthraquinone (or DiMAO) and its precursor, octahydro-DiMAQ (or ODiMAQ), have been synthesized from benzoquinone in high yield and at potentially low cost. Both catalysts were twice as active as anthraquinone in soda, kraft, and polysulfide pulping systems. Pulps produced using these catalysts were as easy to bleach as the corresponding AQ pulps and had the same strength properties. Analysis of unbleached pulps indicated that ODiMAQ was converted to DiMAQ during pulping and that there was approximately four times as much DiMAQ in these cooks as there was residual anthraquinone in the AQ cooks. Consequently, the end-of-cook concentration of DiMAQ may be higher than that of anthraquinone. C1 Inst Paper Sci & Technol, Atlanta, GA 30318 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Dimmel, DR (reprint author), Inst Paper Sci & Technol, 500 10th St NW, Atlanta, GA 30318 USA. NR 14 TC 6 Z9 7 U1 1 U2 1 PU TECH ASSN PULP PAPER IND INC PI NORCROSS PA 15 TECHNOLOGY PARK SOUTH, NORCROSS, GA 30092 USA SN 0734-1415 J9 TAPPI J JI TAPPI J. PD DEC PY 1999 VL 82 IS 12 BP 83 EP 89 PG 7 WC Materials Science, Paper & Wood SC Materials Science GA 262JZ UT WOS:000084064900014 ER PT J AU Taljat, B Zacharia, T Keiser, JR Wang, XL AF Taljat, B Zacharia, T Keiser, JR Wang, XL TI Modeling studies of a composite tube floor in black liquor recovery boilers SO TAPPI JOURNAL LA English DT Article ID RESIDUAL-STRESSES AB Stress-strain analysis of a composite tube floor in black liquor recovery boilers used a commercially available finite element (FE) code. The analysis examined the stress state in an SS304L/SA210 composite tube floor at the normal operating cycle of a boiler and the stresses that develop from temperature excursions during operation. Measurement of residual stresses from tube manufacturing used neutron diffraction. With the residual stresses from assembly welding computed by finite elements, the residual stress measurements were incorporated into the FE models developed for analysis of in-service conditions. Results show high compressive stresses in the overlay material that exceed the yield stress at normal service conditions. They significantly exceed the yield stress during a temperature excursion and become tensile after returning to normal service conditions. A parametric study calculated stresses in the floor tubes as a function of the yield stress and the coefficient of thermal expansion of the overlay material. The analysis provided a generalized solution of stresses in the composite tubes for many overlay materials. Using these results, a recommendation for overlay materials with the most suitable mechanical properties is possible. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Taljat, B (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI Wang, Xun-Li/C-9636-2010 OI Wang, Xun-Li/0000-0003-4060-8777 NR 15 TC 0 Z9 0 U1 0 U2 0 PU TECH ASSN PULP PAPER IND INC PI NORCROSS PA 15 TECHNOLOGY PARK SOUTH, NORCROSS, GA 30092 USA SN 0734-1415 J9 TAPPI J JI TAPPI J. PD DEC PY 1999 VL 82 IS 12 BP 99 EP 108 PG 10 WC Materials Science, Paper & Wood SC Materials Science GA 262JZ UT WOS:000084064900016 ER PT J AU Floro, J AF Floro, J TI Papers presented at the MRS Symposium: Growth Instabilities and Decomposition During Heteroepitaxy, Boston, USA, December 1998 - Preface SO THIN SOLID FILMS LA English DT Editorial Material C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Floro, J (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 1 PY 1999 VL 357 IS 1 BP VII EP VII PG 1 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 269QK UT WOS:000084488900001 ER PT J AU Brown, GW Hawley, ME Theis, CD Yeh, J Schlom, DG AF Brown, GW Hawley, ME Theis, CD Yeh, J Schlom, DG TI Atomic force microscopy examination of the evolution of the surface morphology of Bi4Ti3O12 grown by molecular beam epitaxy SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Symposium on Growth Instabilities and Decomposit ion During Heteroepitaxy at the MRS Fall Meeting CY DEC, 1998 CL BOSTON, MASSACHUSETTS SP Mat Res Soc DE atomic force microscopy; surface morphology; molecular beam epitaxy; Stranski-Krastonov growth ID SCANNING TUNNELING MICROSCOPY; BISMUTH TITANATE; THIN-FILMS; DEPOSITION; ROUGHNESS; SRTIO3 AB The surface morphology of (001) Bi4Ti3O12 grown on (001) SrTiO3 by reactive molecular beam epitaxy (MBE) has been examined using atomic force microscopy (AFM). Initial nucleation of a 1/4 unit cell thick layer is followed by growth of 1/2 unit cell thick layers. Between 9 and 16 layers, a transition to 3-dimensional growth occurs, leading to well-defined mounds. This implies a Stranski-Krastonov growth mode. During growth, the morphology follows a behavior consistent with the dynamic scaling hypothesis and we extract values for the scaling exponents alpha and beta from the AFM data. A thickness variation in alpha is observed and reflects the strain relief associated with the Stranski-Krastonov growth. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div MST8, Los Alamos, NM 87545 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RP Brown, GW (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RI Schlom, Darrell/J-2412-2013 OI Schlom, Darrell/0000-0003-2493-6113 NR 22 TC 4 Z9 4 U1 1 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 1 PY 1999 VL 357 IS 1 BP 13 EP 17 DI 10.1016/S0040-6090(99)00466-6 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 269QK UT WOS:000084488900004 ER PT J AU Jones, ED Follstaedt, DM Lee, SR Reno, JL Millunchick, JM Ahrenkiel, SP Mascarenhas, A Norman, AG Zhang, Y Twesten, RD AF Jones, ED Follstaedt, DM Lee, SR Reno, JL Millunchick, JM Ahrenkiel, SP Mascarenhas, A Norman, AG Zhang, Y Twesten, RD TI Photoluminescence studies of lateral composition modulated short-period AlAs/InAs superlattices SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Symposium on Growth Instabilities and Decomposit ion During Heteroepitaxy at the MRS Fall Meeting CY DEC, 1998 CL BOSTON, MASSACHUSETTS SP Mat Res Soc DE photoluminescence studies; AlAs/InAs superlattices; spontaneous lateral composition modulation ID QUANTUM-WIRE HETEROSTRUCTURES; GROWTH; GAXIN1-XP; ALLOYS AB We present low temperature photoluminescence data for a series of layers exhibiting spontaneous lateral composition modulation in (AlAs)(m) (InAs)(n) short period superlattices grown on InP with differing average lattice constants, i.e. varying global strain, The low temperature photoluminescence peak energies were found to be much lower than the corresponding energy expected for the equivalent InxAl1-xAs alloys. The bandgap energy reductions are found to approach 500 meV and this reduction is found to correlated with the 'strength' of the composition modulation wave amplitude. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Phys & Chem Sci Ctr, Albuquerque, NM 87185 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Illinois, Ctr Microanal, Urbana, IL 61801 USA. RP Jones, ED (reprint author), Sandia Natl Labs, Phys & Chem Sci Ctr, POB 5800, Albuquerque, NM 87185 USA. RI Norman, Andrew/F-1859-2010 OI Norman, Andrew/0000-0001-6368-521X NR 15 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 1 PY 1999 VL 357 IS 1 BP 31 EP 34 DI 10.1016/S0040-6090(99)00470-8 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 269QK UT WOS:000084488900008 ER PT J AU Gerling, MC Jossart, G Duh, QY Weier, HU Clark, OH Young, DM AF Gerling, MC Jossart, G Duh, QY Weier, HU Clark, OH Young, DM TI Invasion of human follicular thyroid carcinoma cells in an in vivo invasion model SO THYROID LA English DT Article ID RECONSTITUTED BASEMENT-MEMBRANE; INTERSTITIAL COLLAGENASE; INVITRO ASSAY; GROWTH-FACTOR; TUMOR-CELLS; HUMAN SKIN; MATRIX; ANGIOGENESIS; INHIBITOR AB Models that demonstrate histological invasion of extracellular matrix barriers by tumor cell lines are useful for assessing new methods to treat or prevent tumor metastasis. An in vivo invasion model using acellular human dermal matrix has been described in a murine squamous cell carcinoma line. The present study examined the application of this tumor invasion model to another epithelial cell line derived from a different species. A human follicular thyroid carcinoma cell line, known to be invasive by other assays, was grown on the dermal-epidermal basement membrane surface of human acellular dermal matrix in culture and then grafted in athymic mice. Immunohistochemical staining of type TV collagen was used to identify the basement membrane and invasion was determined as penetration of the basement membrane by tumor cells. Identification of the human tumor cells in the in vivo grafts was done by in situ hybridization with species specific probes. FTC-133 tumor cells did not invade the matrix after 4 weeks of growth in in vitro culture, but there was extensive loss of the basement membrane and infiltration of the tumor cells into the dermis after 2 weeks growth in vivo. This study suggests that the in vivo dermal matrix model of invasion is applicable to a broad range of epithelial carcinoma cell lines to study their capability to penetrate basement membrane. A model such as this may be useful for studying the local effects of genetic manipulations of implanted tumor cell populations, leading to the development of therapeutic agents that block invasion. C1 Univ Calif San Diego, Sch Med, San Francisco, CA USA. Univ Calif San Francisco, Dept Surg, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Young, DM (reprint author), NB 3A Dept Surg, 1001 Potrero Ave, San Francisco, CA 94110 USA. NR 26 TC 2 Z9 2 U1 2 U2 3 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1050-7256 J9 THYROID JI Thyroid PD DEC PY 1999 VL 9 IS 12 BP 1221 EP 1226 DI 10.1089/thy.1999.9.1221 PG 6 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 273TH UT WOS:000084723200011 PM 10646662 ER PT J AU Sun, YW Clement, TP AF Sun, YW Clement, TP TI A decomposition method for solving coupled multi-species reactive transport problems SO TRANSPORT IN POROUS MEDIA LA English DT Article DE analytical solution; partial differential equation; reactive transport; multi-species; decomposition ID DECAY AB Concerns over the problems associated with mixed waste groundwater contamination have created a need for more complex models that can represent reactive contaminant fate and transport in the subsurface. In the literature, partial differential equations describing solute transport in porous media are solved either for a single reactive species in one, two or three dimensions, or for a limited number of reactive species in one dimension. Those solutions are constrained by many simplifying assumptions. Often, it is desirable to simulate transport in two or three dimensions for a more practical system that might have multiple reactive species. This paper presents a decomposition method to solve the partial differential equations of multi-dimensional, multi-species transport problems that are coupled by linear reactions. A matrix method is suggested as a tool for describing the reaction network. In this way, the level of complexity required to solve the multi-species reactive transport problem is significantly reduced. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Sun, YW (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Sun, Yunwei/C-9751-2010 NR 13 TC 30 Z9 30 U1 0 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-3913 J9 TRANSPORT POROUS MED JI Transp. Porous Media PD DEC PY 1999 VL 37 IS 3 BP 327 EP 346 DI 10.1023/A:1006507514019 PG 20 WC Engineering, Chemical SC Engineering GA 240JL UT WOS:000082822800004 ER PT J AU Yashar, PC Sproul, WD AF Yashar, PC Sproul, WD TI Nanometer scale multilayered hard coatings SO VACUUM LA English DT Article ID X-RAY-DIFFRACTION; EPITAXIAL TIN/NBN SUPERLATTICES; HIGH MECHANICAL HARDNESS; CNX/ZRN MULTILAYERS; THIN-FILMS; POLYCRYSTALLINE; NANOINDENTATION; STABILIZATION; DEPOSITION; TIN/CRN AB Multilayer coatings with layer thicknesses in the nanometer range have been shown to exhibit extremely high hardnesses, making them useful as abrasion-resistant coatings. Hardness values in excess of 5000 kg/mm(2) have been achieved in multilayers composed of two nitride materials, such as TiN and VN, with bilayer periods of 5-10 nm. This article begins with a review of the deposition of multilayered coatings by reactive sputtering and the characterization of these coatings by transmission electron microscopy and X-ray diffraction. The hardness enhancements observed in both isostructural and non-isostructural nanometer-scale multilayers are then reviewed. Several explanations for this enhancement in hardness have been developed in order to understand the hardening process and to develop coatings with even higher hardness. Models based on dislocation motion within layers and across layer interfaces, as well as Hall-Fetch-type models, have successfully been applied to multilayers to explain this hardness enhancement, and they are briefly outlined. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. React Sputtering Inc, Santa Barbara, CA 93111 USA. RP Yashar, PC (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mail Stop G755, Los Alamos, NM 87545 USA. NR 57 TC 302 Z9 310 U1 3 U2 77 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0042-207X J9 VACUUM JI Vacuum PD DEC PY 1999 VL 55 IS 3-4 BP 179 EP 190 DI 10.1016/S0042-207X(99)00148-7 PG 12 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 264HY UT WOS:000084175900002 ER PT J AU Webb, JD Keyes, BM Ahrenkiel, RK Wanlass, MW Ramanathan, K Gedvilas, LM Olson, MR Dippo, P Jones, KM AF Webb, JD Keyes, BM Ahrenkiel, RK Wanlass, MW Ramanathan, K Gedvilas, LM Olson, MR Dippo, P Jones, KM TI Fourier transform-luminescence spectroscopy of semiconductor thin films and devices SO VIBRATIONAL SPECTROSCOPY LA English DT Article DE Fourier transform; semiconductor; thin films ID ROOM-TEMPERATURE MEASUREMENT; FT-RAMAN SPECTROPHOTOMETER; PHOTOLUMINESCENCE SPECTRA; CRYSTALS AB We have been successful in adapting Fourier transform (FT) Raman accessories and spectrophotometers for sensitive measurements of the photoluminescence (PL) spectra of photovoltaic materials and devices. In many cases, the sensitivity of the FT technique allows rapid room temperature measurements of weak luminescence spectra that cannot be observed using dispersive PL spectrophotometers. We present here the results of a number of studies of material and device quality obtained using FT-luminescence spectroscopy, including insights into bandgap variations, defect and impurity effects, and relative recombination rates. We also describe our approach to extending the range of the FT-Raman spectrophotometer to cover the region from 11,500 to 3700 cm(-1), enabling FT-luminescence measurements to be made from 1.42 to 0.46 eV, and our investigation of FT-PL microspectroscopy. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Webb, JD (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 24 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-2031 J9 VIB SPECTROSC JI Vib. Spectrosc. PD DEC PY 1999 VL 21 IS 1-2 BP 3 EP 15 DI 10.1016/S0924-2031(99)00051-X PG 13 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 264HX UT WOS:000084175800001 ER PT J AU Tartakovsky, DM AF Tartakovsky, DM TI Stochastic modeling of heterogeneous phreatic aquifers SO WATER RESOURCES RESEARCH LA English DT Article ID FLOW; MEDIA AB Phreatic flow in heterogeneous aquifers is analyzed by treating hydraulic conductivity as a random field with known statistics. A set of equations for the first and second ensemble moments of hydraulic head and phreatic surface is derived. These equations allow one to predict the behavior of phreatic aquifers, as well as to assess the uncertainty associated with such predictions. Perturbation analysis in variance of log hydraulic conductivity is employed to close the moments equations. This leads to a recursive initial boundary value problem. C1 Univ Calif Los Alamos Natl Lab, Sci Comp Grp, Los Alamos, NM 87545 USA. RP Tartakovsky, DM (reprint author), Univ Calif Los Alamos Natl Lab, Sci Comp Grp, Los Alamos, NM 87545 USA. RI Tartakovsky, Daniel/E-7694-2013 NR 14 TC 8 Z9 8 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD DEC PY 1999 VL 35 IS 12 BP 3941 EP 3945 DI 10.1029/1999WR900280 PG 5 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 264GX UT WOS:000084173200030 ER PT J AU Ferrari, ES Roberts, KJ Sansone, M Adams, D AF Ferrari, ES Roberts, KJ Sansone, M Adams, D TI A multi-edge X-ray absorption spectroscopy study of the reactivity of zinc di-alkyl-di-thiophosphates anti-wear additives 2. In situ studies of steel/oil interfaces SO WEAR LA English DT Article DE anti-corrosion/wear additives; zinc di-alkyl-di-thiophosphate; X-ray absorption spectroscopy; synchrotron radiation; metal/oil interfaces ID K-EDGE; FILMS; MECHANISM; SURFACES; SPECTRA AB Multi-edge X-ray absorption spectroscopy, using synchrotron radiation, was used to examine changes in the structure and chemical composition of steel/oil interfaces when mediated by the presence of the anti-wear additive zinc di-alkyl-di-thiophosphate (ZDDP). The experiments were carried out at the Zn, Fe, O and C K-edges and the Zn and Fe L-II/(III)-edges. Examination of the steel substrate, prior to reaction, revealed that the metal surface was partly oxidised, with the oxide structure mostly involving the iron atoms having a tetrahedral coordination to oxygen. Distinct changes to the oxide structure were observed following its reaction associated with the formation of its interface with ZDDP formulated in lubrication oil. Temperature programmed studies on the interfacial structure were consistent with a model involving ion exchange between Zn atoms in ZDDP and Fe(II) cations in the oxide in a reaction that appeared to be reversible below 75 degrees C. Grazing incidence absorption spectroscopy measurements provided evidence for the breakdown of the ZDDP molecule following its adsorption onto the steel substrate surface. At higher temperatures chemical reaction between the additive and the surface oxide layer led to the formation of an amorphous anti-wear film. The structure of this film was consistent with a Zn-O bond (1.98 Angstrom) typical of partly oxidised sulphur atoms associated with the formation of a random network glass structure with corner sharing thiophosphate and sulphate anions containing network-modifying Zn cations, A reaction scheme consistent with the proposed structure is discussed. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Heriot Watt Univ, Dept Mech & Chem Engn, Ctr Mol & Interface Engn, Edinburgh EH14 4AS, Midlothian, Scotland. CCLRL, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. Brookhaven Natl Lab, Exxon PRT, Upton, NY 11973 USA. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. Infineum UK, Abingdon OX13 6BB, Oxon, England. RP Roberts, KJ (reprint author), Heriot Watt Univ, Dept Mech & Chem Engn, Ctr Mol & Interface Engn, Edinburgh EH14 4AS, Midlothian, Scotland. NR 31 TC 27 Z9 27 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD DEC PY 1999 VL 236 IS 1-2 BP 259 EP 275 DI 10.1016/S0043-1648(99)00286-0 PG 17 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 271JP UT WOS:000084590700029 ER PT J AU Hou, PY Niu, Y Sum, TJ Stringer, J AF Hou, PY Niu, Y Sum, TJ Stringer, J TI Effect of HCl on the corrosion and wear of in-bed tubes in a laboratory simulated bubbling fluidized bed SO WEAR LA English DT Article; Proceedings Paper CT International Conference on Erosion, Abrasion and Wear CY SEP 13-17, 1998 CL CHURCHILL COLL, CAMBRIDGE, ENGLAND SP Electr Power Res Inst HO CHURCHILL COLL DE corrosion; wear; in-bed tube ID STEEL; CHLORIDES; OXIDATION; PRESSURE; WASTAGE AB Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. The effect of chlorine on in-bed tube wastage and its possible mechanism are being studied using the EPRI/LBNL FBC wastage simulator. This test rig was designed to simulate dense particle impacts on tube bottoms with well-controlled parameters, and has been proven to closely reflect situations found in operating bubbling FBCs, In this study, HCl gas was chosen to be the Cl source and was introduced into the fluidizing air with a 50-ppm concentration. Tests were performed at temperatures ranging from ambient to 400 degrees C using 1018 low carbon steel rods in a bed of commercial SiO(2) sand that had an average size of 800 mu m. The wear profile after each test was measured using a profilometer. Results showed an increase in material wastage rates in the presence of HCl, and that the rate was significantly higher with higher test temperatures. Microstructural and chemical analysis of the wear surface and corrosion products are reported. It is concluded that the dominating effect of HCl on the wastage rates is due to an enhanced oxidation and a reduced scale adherence. (C) 1999 Elsevier Science S.A. AU rights reserved. C1 Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Chinese Acad Sci, Inst Corros & Protect Met, Shenyang, Peoples R China. Elect Power Res Inst, Palo Alto, CA 94304 USA. RP Hou, PY (reprint author), Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 26 TC 6 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD DEC PY 1999 VL 233 BP 635 EP 646 DI 10.1016/S0043-1648(99)00247-1 PG 12 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 271JM UT WOS:000084590500070 ER PT J AU Beck, HP Monzel, H Haberkorn, R Stephens, PW Dinnebier, R AF Beck, HP Monzel, H Haberkorn, R Stephens, PW Dinnebier, R TI Synthesis and crystal structure of Rb3PbCl5 SO ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE LA German DT Article DE ternary halides; lone pair cation ID BINARY-SYSTEM INCL-SNCL2; PHASE-DIAGRAM; REDETERMINATION AB The synthesis of the hitherto unknown compound Rb3PbCl5 in the quasi-binary system RbCl/PbCl2 and its structure determination is reported. This 3:1-phase decomposes peritectoidally at 305 degrees C and crystallizes in a so far unknown structure type in the orthorhombic space group Pnma (a = 863.498(5) pm, b = 1573.11(1) pm, c = 838.875(5) pm). It shows typical structural characteristics of ns(2)-configurated cations, although there are more noble gas-configurated cations than ns(2)-configurated cations in the structure. C1 Univ Saarlandes, Inst Anorgan & Analyt Chem & Radiochem, D-66041 Saarbrucken, Germany. SUNY, Dept Phys & Astron, New York, NY USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Bayreuth, Inst Kristallog, Bayreuth, Germany. RP Beck, HP (reprint author), Univ Saarlandes, Inst Anorgan & Analyt Chem & Radiochem, Postfach 15 11 50, D-66041 Saarbrucken, Germany. RI Dinnebier, Robert/B-5642-2015 OI Dinnebier, Robert/0000-0003-2778-2113 NR 17 TC 4 Z9 4 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0044-2313 J9 Z ANORG ALLG CHEM JI Z. Anorg. Allg. Chem. PD DEC PY 1999 VL 625 IS 12 BP 1998 EP 2002 DI 10.1002/(SICI)1521-3749(199912)625:12<1998::AID-ZAAC1998>3.0.CO;2-U PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 267PR UT WOS:000084368900011 ER PT J AU Cannon, RM Esposito, L AF Cannon, RM Esposito, L TI High temperature colloidal behavior: Particles in liquid silicates SO ZEITSCHRIFT FUR METALLKUNDE LA English DT Review ID INTERGRANULAR FILM THICKNESS; IMPROVED FRACTURE-TOUGHNESS; TOUGHENED SILICON-CARBIDE; GRAIN-BOUNDARY PHENOMENA; PHASE-SINTERED ALUMINA; HAMAKER CONSTANTS; MICROSTRUCTURAL DESIGN; PLAUSIBLE CONCEPTS; AMORPHOUS FILMS; NITRIDE AB A provisional framework for comprehending many trends in the evolution of solid-liquid systems at high temperature emerged from synthesizing aspects of theories for interfacial wetting and stable grain boundary films with those for sintering and microstructural evolution of materials with low dihedral angles. The energetic factors that dictate the morphology and connectivity of solid particle networks that may provide a basis to describe and understand colloidal systems under conditions wherein particles can change shape. The stability of such networks plus the role of interfacial adsorption layers are elucidated. A critique of reported behavior of several ceramic systems yields some support for these ideas but identifies discrepancies. Experiments were performed involving Si(3)N(4) and other powders dispersed into glass forming silicates, and also involving grain boundary penetration by similar liquids into dense, liquid phase sintered Si(3)N(4). Several general trends emerged in terms of flocculation behavior of Si(3)N(4) particles. The existence of equilibrium boundary films implies that particles being generally attractive should tend to form stable networks with relatively high density. However, two processes eventually disrupt well packed flocs and even dense polycrystalline material upon exposure to the liquids. One ensues from a transient wetting of grain boundaries that are not pre-equilibrated with the liquid. Secondly, anisotropic grain growth can generate sufficient forces to rupture a flocculated, partially sintered particle network. This can lead to a suspension of very low particle density that yet contains small clusters of flocculated particles. With MgO and Al(2)O(3), an observed tendency to form small flocs or chains is interpreted to mean that for certain special particle alignments, low energy boundaries are formed. This may also lead to loose, interconnected networks. With metallic particles, open networks quickly formed, which were stabilized by growth of necks with dry boundaries which did not readily admit particle rearrangement. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Cannon, RM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. EM cannon@socrates.berkeley.edu OI Esposito, Laura/0000-0001-6196-4901 NR 102 TC 31 Z9 32 U1 1 U2 9 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0044-3093 J9 Z METALLKD JI Z. Metallk. PD DEC PY 1999 VL 90 IS 12 BP 1002 EP 1015 PG 14 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 269LQ UT WOS:000084479300008 ER PT J AU Crofts, AR Guergova-Kuras, M Huang, LS Kuras, R Zhang, ZL Berry, EA AF Crofts, AR Guergova-Kuras, M Huang, LS Kuras, R Zhang, ZL Berry, EA TI Mechanism of ubiquinol oxidation by the bc(1) complex: Role of the iron sulfur protein and its mobility SO BIOCHEMISTRY LA English DT Article ID CYTOCHROME-C OXIDOREDUCTASE; PHOTOSYNTHETIC REACTION-CENTER; MITOCHONDRIAL BC1 COMPLEX; BOVINE HEART-MITOCHONDRIA; FORMING HYDROGEN-BONDS; ELECTRON-TRANSFER; RHODOBACTER-CAPSULATUS; RHODOPSEUDOMONAS-SPHAEROIDES; UBIHYDROQUINONE OXIDATION; CRYSTAL-STRUCTURE AB Native structures of ubihydroquinone:cytochrome c oxidoreductase (bc(1) complex) from different sources, and structures with inhibitors in place, show a 16-22 Angstrom displacement of the [2Fe-2S] cluster and the position of the C-terminal extrinsic domain of the iron sulfur protein. None of the structures shows a static configuration that would allow catalysis of all partial reactions of quinol oxidation. We have suggested that the different conformations reflect a movement of the subunit necessary for catalysis. The displacement from an interface with cytochrome cl in native crystals to an interface with cytochrome b is induced by stigmatellin or 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT) and involves ligand formation between His-161 of the [2Fe-2S] binding cluster and the inhibitor. The movement is a rotational displacement, so that the same conserved docking surface on the iron sulfur protein interacts with cytochrome cl and with cytochrome b. The mobile extrinsic domain retains essentially the same tertiary structure, and the anchoring N-terminal tail remains in the same position. The movement occurs through an extension of a helical segment in the short linking span. We report details of the protein structure for the two main configurations in the chicken heart mitochondrial complex and discuss insights into mechanism provided by the structures and by mutant strains in which the docking at the cytochrome b interface is impaired. The movement of the iron sulfur protein represents a novel mechanism of electron transfer, in which a tethered mobile head allows electron transfer through a distance without the entropic loss from free diffusion. C1 Univ Illinois, Ctr Biophys & Computat Biol, Urbana, IL 61801 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Crofts, AR (reprint author), Univ Illinois, Ctr Biophys & Computat Biol, Urbana, IL 61801 USA. FU NIDDK NIH HHS [DK 44842]; NIGMS NIH HHS [GM 35438] NR 72 TC 87 Z9 88 U1 2 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD NOV 30 PY 1999 VL 38 IS 48 BP 15791 EP 15806 DI 10.1021/bi990961u PG 16 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263FU UT WOS:000084115400012 PM 10625445 ER PT J AU Crofts, AR Barquera, B Gennis, RB Kuras, R Guergova-Kuras, M Berry, EA AF Crofts, AR Barquera, B Gennis, RB Kuras, R Guergova-Kuras, M Berry, EA TI Mechanism of ubiquinol oxidation by the bc(1) complex: Different domains of the quinol binding pocket and their role in the mechanism and binding of inhibitors SO BIOCHEMISTRY LA English DT Article ID CYTOCHROME-C OXIDOREDUCTASE; IRON-SULFUR PROTEIN; ELECTRON-TRANSFER CHAIN; RHODOPSEUDOMONAS-SPHAEROIDES; RHODOBACTER-SPHAEROIDES; BOVINE HEART; Q(O) SITE; Q-CYCLE; UBIQUINOL-CYTOCHROME-C2 OXIDOREDUCTASE; UBIHYDROQUINONE OXIDATION AB Structures Of mitochondrial ubihydroquinone:cytochrome c oxidoreductase (bc(1) complex) from several animal sources have provided a basis for understanding the functional mechanism at the molecular level. Using structures of the chicken complex with and without inhibitors, we analyze the effects of mutation on quinol oxidation at the Q(o) site of the complex. We suggest a mechanism for the reaction that incorporates two features revealed by the structures, a movement of the iron sulfur protein between two separate reaction domains on cytochrome c(1) and cytochrome b and a bifurcated volume for the Q(o) site. The volume identified by inhibitor binding as the Q(o) site has two domains in which inhibitors of different classes bind differentially; a domain proximal to heme b(L), where myxothiazole and beta-methoxyacrylate(MOA-) type inhibitors bind (class II), and a distal domain close to the iron sulfur protein docking interface, where stigmatellin and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiaole (UHDBT) bind (class I). Displacement of one class of inhibitor by another is accounted for by the overlap of their volumes, since the exit tunnel to the lipid phase forces the hydrophobic "tails" to occupy common space. We conclude that the site can contain only one "tailed" occupant, either an inhibitor or a quinol or one of their reaction products. The differential sensitivity of strains with mutations in the different domains is explained by the proximity of the affected residues to the binding domains of the inhibitors. New insights into mechanism are provided by analysis of mutations that affect changes in the electron paramagnetic resonance (EPR) spectrum of the iron sulfur protein, associated with its interactions with the Q(o)-site occupant. The structures show that all interactions with the iron sulfur protein must occur at the distal position. These include interactions between quinone, or class I inhibitors, and the reduced iron sulfur protein and formation of a reaction complex between quinol and oxidized iron sulfur protein. The step with high activation energy is after formation of the reaction complex, likely in formation of the semiquinone and subsequent dissociation of the complex into products. We suggest that further progress of the reaction requires a movement of semiquinone to the proximal position, thus mapping the bifurcated reaction to the bifurcated volume. We suggest that such a movement, together with a change in conformation of the site, would remove any semiquinone formed from further interaction with the oxidized [2Fe-2S] center and also from reaction with O-2 to form superoxide anion. We also identify two separate reaction paths for exit of the two protons released in quinol oxidation. C1 Univ Illinois, Ctr Biophys & Computat Biol, Urbana, IL 61801 USA. Univ Illinois, Dept Biochem, Urbana, IL 61801 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Crofts, AR (reprint author), Univ Illinois, Ctr Biophys & Computat Biol, 388 Morrill Hall,505 S Goodwin, Urbana, IL 61801 USA. FU NIDDK NIH HHS [DK 44842]; NIGMS NIH HHS [GM 35438] NR 67 TC 131 Z9 135 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD NOV 30 PY 1999 VL 38 IS 48 BP 15807 EP 15826 DI 10.1021/bi990962m PG 20 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263FU UT WOS:000084115400013 PM 10625446 ER PT J AU Crofts, AR Hong, SJ Zhang, ZL Berry, EA AF Crofts, AR Hong, SJ Zhang, ZL Berry, EA TI Physicochemical aspects of the movement of the rieske iron sulfur protein during quinol oxidation by the bc(1) complex from mitochondria and photosynthetic bacteria SO BIOCHEMISTRY LA English DT Article ID CYTOCHROME-C OXIDOREDUCTASE; ELECTRON-TRANSFER CHAIN; RHODOPSEUDOMONAS-SPHAEROIDES; RHODOBACTER-SPHAEROIDES; BOVINE HEART; BC1 COMPLEX; Q(O) SITE; Q-CYCLE; UBIQUINONE; MECHANISM AB Crystallographic structures for the mitochondrial ubihydroquinone:cytochrome c oxidoreductase (bc(1) complex) from different sources, and with different inhibitors in cocrystals, have revealed that the extrinsic domain of the iron sulfur subunit is not fixed [Zhang, Z., Huang, L., Shulmeister, V. M., Chi, Y.-I., Kim, K. K., Hung, L.-W., Crofts, A. R., Berry, E. A., and Kim, S.-H. (1998) Nature (London), 392, 677-684], but moves between reaction domains on cytochrome cl and cytochrome b subunits. We have suggested that the movement is necessary for quinol oxidation at the Q(o) site of the complex. In this paper, we show that the electron-transfer reactions of the high-potential chain of the complex, including oxidation of the iron sulfur protein by cytochrome c(1) and the reactions by which oxidizing equivalents become available at the Q(o) site, are rapid compared to the rate-determining step. Activation energies of partial reactions that contribute to movement of the iron sulfur protein have been measured and shown to be lower than the high activation barrier associated with quinol oxidation. We conclude that the movement is not the source of the activation barrier. We estimate the occupancies of different positions for the iron sulfur protein from the crystallographic electron densities and discuss the parameters determining the binding of the iron sulfur protein in different configurations. The low activation barrier is consistent with a movement between these locations through a constrained diffusion. Apart from ligation in enzyme-substrate or inhibitor complexes, the binding forces in the native structure are likely to be less than or equal to RT, suggesting that the mobile head can explore the reaction interfaces through stochastic processes within the time scale indicated by kinetic measurements. C1 Univ Illinois, Ctr Biophys & Computat Biol, ARC, Urbana, IL 61801 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Crofts, AR (reprint author), Univ Illinois, Ctr Biophys & Computat Biol, ARC, 388 Morrill Hall,505 S Goodwin, Urbana, IL 61801 USA. FU NIDDK NIH HHS [DK 44842]; NIGMS NIH HHS [GM 35438] NR 44 TC 47 Z9 49 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 NOV 30 PY 1999 VL 38 IS 48 BP 15827 EP 15839 DI 10.1021/bi990963e PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263FU UT WOS:000084115400014 PM 10625447 ER PT J AU Kerrick, DM Caldeira, K AF Kerrick, DM Caldeira, K TI Was the Himalayan orogen a climatically significant coupled source and sink for atmospheric CO2 during the Cenozoic? SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE metamorphism; chemical weathering; Cenozoic; carbon dioxide; Himalayas; paleoclimatology ID CARBON-CYCLE; EVOLUTION; ANNAPURNA; COLLISION; SEDIMENTS; FEEDBACK; CLIMATE; BALANCE; BUDGET; MODEL AB The hypothesis that the Himalayan orogen was a climatically significant coupled source and sink for atmospheric CO2 during the Cenozoic is evaluated in light of the timing, duration and CO2 fluxes associated with Himalayan metamorphism and chemical weathering. We suggest that diachronous Eohimalayan metamorphism occurred over a similar to 20 m.y. time span (Middle Eocene to Early Oligocene) with total metamorphic CO2 production of similar to 4-10 x 10(18) mel. Because this is much greater than the amount of carbon stored in the atmosphere and oceans, and because uplift and accelerated erosion began at least similar to 5 m.y. after the peak of metamorphism, we conclude that it is implausible that CO2 produced by metamorphism in the Himalayan orogen was consumed millions of years later by erosion-enhanced weathering in this orogen. Assuming a global climate/silicate-weathering feedback, we estimate that metamorphic CO2 degassing from the Himalayan orogen would have produced a warming of <0.5 degrees C, and enhanced weathering in this orogen would have produced a cooling of <0.2 degrees C: thus, direct climate effects of this degassing and weathering were likely to have been minor. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, Livermore, CA 94550 USA. RP Kerrick, DM (reprint author), Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. RI Caldeira, Ken/E-7914-2011 NR 47 TC 24 Z9 24 U1 1 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD NOV 30 PY 1999 VL 173 IS 3 BP 195 EP 203 DI 10.1016/S0012-821X(99)00229-0 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 260GN UT WOS:000083941300005 ER PT J AU Pang, HM Pavski, V Yeung, ES AF Pang, HM Pavski, V Yeung, ES TI DNA sequencing using 96-capillary array electrophoresis SO JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS LA English DT Review DE DNA sequencing; capillary array electrophoresis ID CAPILLARY GEL-ELECTROPHORESIS; LASER-INDUCED FLUORESCENCE; HIGH-SPEED; POLY(ETHYLENE OXIDE); FILLED CAPILLARIES; LOW-COST; SEPARATIONS; FRAGMENTS; OPTIMIZATION; TEMPERATURE AB Practical DNA sequencing in a rugged capillary array electrophoresis system coupled directly to 96-well microtiter plates is demonstrated. A CCD detector was used to monitor all capillaries simultaneously with laser-induced fluorescence at 1.75 frames per second. The reconstructed electropherograms show good signal-to-noise ratios and resolution for the entire capillary array. The system used standard dye labeling and image splitting to obtain fluorescence intensities in two wavelength regions to allow calling up to 410 bases for the DNA sequence. The use of a replaceable poly(ethylene oxide) matrix and a protective poly(vinylpyrrolidone) coating allows high separation speed and short turnaround time for high throughput DNA sequencing. Critical evaluation of the system performance over repeated runs with base calling is presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. FU NHGRI NIH HHS [HG-01385] NR 32 TC 28 Z9 30 U1 4 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-022X J9 J BIOCHEM BIOPH METH JI J. Biochem. Biophys. Methods PD NOV 30 PY 1999 VL 41 IS 2-3 BP 121 EP 132 DI 10.1016/S0165-022X(99)00042-1 PG 12 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 265YY UT WOS:000084274900005 PM 10626770 ER PT J AU Lyness, JN Delves, LM AF Lyness, JN Delves, LM TI On the implementation of a modified Sag-Szekeres quadrature method SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article ID VARIABLE TRANSFORMATION AB We describe a modified Sag-Szekeres multidimensional quadrature algorithm and discuss its implementation as a general-purpose library procedure on serial and parallel architectures. Examples illustrate its effectiveness for both smooth and singular integrands. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Liverpool, Inst Adv Sci Computat, Liverpool L69 3BX, Merseyside, England. NR 8 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD NOV 30 PY 1999 VL 112 IS 1-2 BP 189 EP 200 DI 10.1016/S0377-0427(99)00221-6 PG 12 WC Mathematics, Applied SC Mathematics GA 259UE UT WOS:000083911700014 ER PT J AU Samon, JM Schultz, JM Hsiao, BS Seifert, S Stribeck, N Gurke, I Collins, G Saw, C AF Samon, JM Schultz, JM Hsiao, BS Seifert, S Stribeck, N Gurke, I Collins, G Saw, C TI Structure development during the melt spinning of polyethylene and poly(vinylidene fluoride) fibers by in situ synchrotron small- and wide-angle X-ray scattering techniques SO MACROMOLECULES LA English DT Article ID PARTIALLY CRYSTALLINE POLYMERS; DENSITY-FLUCTUATIONS; POLYPROPYLENE; RADIATION; POLY(ETHYLENE-TEREPHTHALATE); INDUCTION; KINETICS; PET AB In the present study, the structural and morphological development during melt spinning of polyethylene and poly(vinylidene fluoride) fibers was studied using simultaneous in-situ synchrotron small- and wide-angle X-ray scattering (SWAXS) techniques. The spinning apparatus consisted of a single screw extruder, which was mounted on a horizontal platform that could be translated in the vertical direction allowing different spinneret distances to be sampled with the X-ray beam. Effects of take-up speed (10.6-61.0 mpm) and spinneret distance (30-87.5 cm) on crystallinity and morphological parameters were investigated. A suggested model of structural development during crystallization details the formation of defective shish crystals, followed by the formation of kebob crystals. The defective shish-kebob structure eventually transforms into a well-defined lamellar structure. This model is consistent with the qualitative appearance of the two-dimensional SAXS and WAXS patterns, as well as the quantitative analysis of the SAXS/WAXS data using position-sensitive wire detectors. C1 Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Argonne Natl Lab, Dept Chem, Argonne, IL 60439 USA. Hoechst Celanese Corp, Corp Res & Technol, Summit, NJ 07901 USA. Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RP Hsiao, BS (reprint author), Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. NR 41 TC 70 Z9 71 U1 1 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 30 PY 1999 VL 32 IS 24 BP 8121 EP 8132 DI 10.1021/ma9906332 PG 12 WC Polymer Science SC Polymer Science GA 261QL UT WOS:000084020000024 ER PT J AU Dair, BJ Honeker, CC Alward, DB Avgeropoulos, A Hadjichristidis, N Fetters, LJ Capel, M Thomas, EL AF Dair, BJ Honeker, CC Alward, DB Avgeropoulos, A Hadjichristidis, N Fetters, LJ Capel, M Thomas, EL TI Mechanical properties and deformation behavior of the double gyroid phase in unoriented thermoplastic elastomers SO MACROMOLECULES LA English DT Article ID GRAIN-BOUNDARY MORPHOLOGY; STAR BLOCK COPOLYMERS; TRIBLOCK COPOLYMER; MICROPHASE SEPARATION; DIBLOCK COPOLYMERS; MOLECULAR-WEIGHT; CUBIC PHASES; TRANSITION; SYSTEMS; ORIENTATION AB The mechanical properties of the double gyroid (DG) cubic phase in glassy-rubbery block copolymer systems are examined. The stress-strain properties of an isoprene-rich polystyrene/polyisoprene/polystyrene (SIS) triblock and a polystyrene/polyisoprene (SI) starblock DG, both comprised of two separate interpenetrating glassy networks embedded in rubbery matrices, are compared to those of the sphere, cylinder, and lamellar morphologies. This 9-dimensionally interpenetrating periodic nanocomposite is found to have superior properties over those of its classical counterparts, attributable to the morphology rather than to the volume fraction of the glassy component, the architecture of the molecule, or the molecular weight. The DG is the only polygranular/isotropic thermoplastic elastomer morphology which exhibits necking and drawing and which requires considerably higher stresses for deformation up to 200% strain than any of the three classical microdomain morphologies. The deformation behavior of the DG is further investigated as a function of applied strain using in situ synchrotron small-angle X-ray scattering. Yielding and necking are observed at similar to 20% strain, accompanied by sudden changes in the SAXS patterns: the characteristic Bragg rings of the DG disappear and are replaced by a lobe pattern containing streaks and diffuse scattering. Analysis of the {211} reflection in the SAXS data indicates that PS networks play a large role in governing the deformation behavior. The necking behavior of the DG suggests a different deformation mechanism. The DG samples recover both microscopically and macroscopically upon unloading and annealing, indicating that the complex interconnected nanocomposite structure was not permanently damaged, even after having been stretched to 600% strain. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Univ Athens, Dept Chem, Athens 15771, Greece. Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. Exxon Res & Engn Co, Corp Res Sci Lab, Annandale, NJ 08801 USA. RP Thomas, EL (reprint author), MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RI Avgeropoulos, Apostolos/I-5772-2012 NR 64 TC 76 Z9 77 U1 3 U2 32 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 30 PY 1999 VL 32 IS 24 BP 8145 EP 8152 DI 10.1021/ma990666h PG 8 WC Polymer Science SC Polymer Science GA 261QL UT WOS:000084020000027 ER PT J AU Trice, RW Su, YJ Faber, KT Wang, H Porter, W AF Trice, RW Su, YJ Faber, KT Wang, H Porter, W TI The role of NZP additions in plasma-sprayed YSZ: microstructure, thermal conductivity and phase stability effects SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE thermal barrier coatings; zirconium phosphate; yttria stabilized zirconia; thermal conductivity ID CHEMICAL-STABILITY; EXPANSION CERAMICS; COATINGS; FAMILY AB A concept for lowering the thermal conductivity of plasma-sprayed yttria-stabilized zirconia (YSZ) was evaluated by adding a low thermal conductivity secondary phase. Ca0.5Sr0.5Zr4P6O24, a member of the zirconium phosphate or NZP family, was co-sprayed with YSZ using the recently patented small-particle plasma-spray process. The amount of NZP phase in the YSZ varied from 4 to 18 vol.%. Transmission electron microscopy revealed that the plasma-sprayed NZP existed as 30-50 nm size grains when sprayed with YSZ. Between 100 and 1200 degrees C, reductions in the thermal conductivity of NZP/VSZ composite coatings compared to YSZ-only coatings were traced to porosity effects. The NZP phase destabilized the t'-ZrO2 phase of the YSZ, favoring the formation of t-ZrO2, then m-ZrO2, a phase with a high-thermal conductivity. Due to this phase change, a large hysteresis was observed in thermal conductivity during the initial heat-up and cool down cycles of the NZP containing samples. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Faber, KT (reprint author), Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Faber, Katherine/B-6741-2009; Wang, Hsin/A-1942-2013 OI Wang, Hsin/0000-0003-2426-9867 NR 26 TC 12 Z9 13 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD NOV 30 PY 1999 VL 272 IS 2 BP 284 EP 291 DI 10.1016/S0921-5093(99)00468-2 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 257MP UT WOS:000083785900007 ER PT J AU Aumentado, J Chandrasekhar, V Eom, J Baldo, PM Rehn, LE AF Aumentado, J Chandrasekhar, V Eom, J Baldo, PM Rehn, LE TI Proximity effect thermometer for local electron temperature measurements on mesoscopic samples SO APPLIED PHYSICS LETTERS LA English DT Article ID SPIN-GLASS WIRES AB Using the strong temperature-dependent resistance of a normal metal wire in proximity to a superconductor, we have been able to measure the local temperature of electrons heated by flowing a direct-current (dc) in a metallic wire to within a few tens of millikelvin at low temperatures. By placing two such thermometers at different parts of a sample, we have been able to measure the temperature difference induced by a dc flowing in the samples. This technique may provide a flexible means of making quantitative thermal and thermoelectric measurements on mesoscopic metallic samples. (C) 1999 American Institute of Physics. [S0003-6951(99)04648-3]. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Aumentado, J (reprint author), Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RI Aumentado, Jose/C-2231-2009 OI Aumentado, Jose/0000-0001-5581-1466 NR 11 TC 17 Z9 17 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 29 PY 1999 VL 75 IS 22 BP 3554 EP 3556 DI 10.1063/1.125386 PG 3 WC Physics, Applied SC Physics GA 258NT UT WOS:000083845800040 ER PT J AU Berger, EL Harris, BW Sullivan, Z AF Berger, EL Harris, BW Sullivan, Z TI Single-top-squark production via R-parity-violating supersymmetric couplings in hadron collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLLIDERS; MODELS AB Single-top-squark production via qq' --> (t) over tilde(1) probes R-parity-violating extensions of the minimal supersymmetric standard model through the lambda(3ij)" couplings. For masses in the range 180-325 GeV, and lambda(3ij)" > 0.02-0.06, we show that discovery of the top squark is possible with 2 fb(-1) of integrated luminosity at run II of the Fermilab Tevatron. The bound on lambda(3ij)" can be reduced by up to 1 order of magnitude with existing data from run I, and by 2 orders of magnitude at run IT if the top squark is not found. C1 Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. RP Berger, EL (reprint author), Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. NR 15 TC 51 Z9 51 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 NOV 29 PY 1999 VL 83 IS 22 BP 4472 EP 4475 DI 10.1103/PhysRevLett.83.4472 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100007 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adams, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M 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, N da Motta, W 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, B 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, E 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 Wahl, HD Warchol, J Watts, G Wayne, M Weerts, W 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 Adams, I Adams, DL Adams, M Ahn, S Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M 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, N da Motta, W 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, B 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, E 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 Wahl, HD Warchol, J Watts, G Wayne, M Weerts, W 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 D0 Collaboration TI Search for R-Parity violating supersymmetry in the dielectron channel SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODEL AB We report on a search for R-parity-violating supersymmetry in p (p) over bar collisions at root s = 1.8 TeV using the DO detector at Fermilab. Events with at least two electrons and four or more jets were studied. We observe two events in 99 +/- 4.4 pb(-1) of data, consistent with the expected background of 1.8 +/- 0.4 events. This result is interpreted within the framework of minimal low-energy supergravity supersymmetry models. Squarks with mass below 243 GeV/c(2) and gluinos with mass below 227 GeV/c(2) are excluded at the 95% C.L. for A(0) = 0, mu < 0, tan beta = 2, and a finite value for any one of the six R-parity-violating couplings lambda(1jk)' (j = 1, 2 and k = 1, 2, 3). C1 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, Peoples R China. Univ Los Andes, Bogota, Colombia. Univ San Francisco, Quito, Ecuador. Univ Grenoble 1, CNRS, IN2P3, Inst Sci Nucl, Grenoble, France. CEA, Serv Phys Particules, DAPNIA, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Lancaster, Lancaster, England. Univ Arizona, Tucson, AZ 85721 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. 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. NYU, New York, NY 10003 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), Univ Buenos Aires, Buenos Aires, DF, Argentina. RI Peters, Michael/B-4973-2009; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Leflat, Alexander/D-7284-2012; Dudko, Lev/D-7127-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016; OI Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Belyaev, Alexander/0000-0002-1733-4408; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108; Hays, Chris/0000-0003-2371-9723 NR 29 TC 28 Z9 28 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 29 PY 1999 VL 83 IS 22 BP 4476 EP 4481 DI 10.1103/PhysRevLett.83.4476 PG 6 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100008 ER PT J AU Appel, R Atoyan, GS Bassalleck, B Bergman, DR Brown, DN Cheung, N Dhawan, S Do, H Egger, J Eilerts, S Felder, C Fischer, H Gach, M Herold, W Issakov, VV Kaspar, H Kraus, DE Lazarus, DM Leipuner, L Lichard, P Lowe, J Lozano, J Ma, H Majid, W Menzel, W Pislak, S Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thomas, TL Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thomas, TL Thompson, JA Truol, P Weyer, H Zeller, ME AF Appel, R Atoyan, GS Bassalleck, B Bergman, DR Brown, DN Cheung, N Dhawan, S Do, H Egger, J Eilerts, S Felder, C Fischer, H Gach, M Herold, W Issakov, VV Kaspar, H Kraus, DE Lazarus, DM Leipuner, L Lichard, P Lowe, J Lozano, J Ma, H Majid, W Menzel, W Pislak, S Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thomas, TL Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thomas, TL Thompson, JA Truol, P Weyer, H Zeller, ME TI New measurement of the properties of the rare decay K+->pi(+)e(+)e(-) SO PHYSICAL REVIEW LETTERS LA English DT Article AB A low-background sample of 10 300 events has been collected for the decay mode K+ --> pi(+)e(+)e(-) experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The branching ratio is measured to be [2.94 +/- 0.05(stat) +/- 0.13(syst) +/- 0.05(model)] x 10(-7), the vector nature of this decay is firmly established, and the decay form factor f(z) = f(0)(1 + delta z)(z = M-ee(2)/m(K)(2)) is determined to have delta = 2.14 +/- 0.13 +/- 0.15, The experiment is described and results discussed in the context of chiral perturbation theory. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Yale Univ, Dept Phys, New Haven, CT 06511 USA. Univ Basel, Inst Phys, CH-4046 Basel, Switzerland. Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. RP Appel, R (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Lichard, Peter/A-4459-2010 OI Lichard, Peter/0000-0003-1581-8545 NR 23 TC 55 Z9 56 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 NOV 29 PY 1999 VL 83 IS 22 BP 4482 EP 4485 DI 10.1103/PhysRevLett.83.4482 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100009 ER PT J AU Luce, TC Lin-Liu, YR Harvey, RW Giruzzi, G Politzer, PA Rice, BW Lohr, JM Petty, CC Prater, R AF Luce, TC Lin-Liu, YR Harvey, RW Giruzzi, G Politzer, PA Rice, BW Lohr, JM Petty, CC Prater, R TI Generation of localized noninductive current by electron cyclotron waves on the DIII-D tokamak SO PHYSICAL REVIEW LETTERS LA English DT Article ID CURRENT DRIVE; PLASMAS; TRANSPORT AB Localized currents due to electron cyclotron current drive have been measured for the first time in experiments on the DIII-D tokamak. The location of driven current in the plasma has been varied from near the center of the tokamak out to half of the minor radius. The measured current drive efficiency agrees with quasilinear Fokker-Planck calculations near the center and exceeds the predicted value with increasing minor radius. Reduction of the trapped electron fraction due to finite collisionality is a leading candidate to explain the discrepancy. C1 Gen Atom Co, San Diego, CA 92186 USA. CompX, Del Mar, CA 92014 USA. Ctr Etud Cadarache, CEA, St Paul Durance, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Luce, TC (reprint author), Gen Atom Co, San Diego, CA 92186 USA. NR 17 TC 59 Z9 59 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 NOV 29 PY 1999 VL 83 IS 22 BP 4550 EP 4553 DI 10.1103/PhysRevLett.83.4550 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100026 ER PT J AU Borca, CN Adenwalla, S Choi, JW Sprunger, PT Ducharme, S Robertson, L Palto, SP Liu, JL Poulsen, M Fridkin, VM You, H Dowben, PA AF Borca, CN Adenwalla, S Choi, JW Sprunger, PT Ducharme, S Robertson, L Palto, SP Liu, JL Poulsen, M Fridkin, VM You, H Dowben, PA TI Lattice-stiffening transition in copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%) SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE FERROELECTRIC TRANSITION; LANGMUIR-BLODGETT-FILMS; ELECTRONIC-STRUCTURE; PHOTOEMISSION; SYSTEMS AB We report the discovery of a compressibility phase transition at 160 K in crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%). This phase transition is distinct from the known bulk ferroelectric-paraelectric phase transition at 353 It and surface ferroelectric phase transition at 295 K. The new phase transition is characterized by an increase in the effective Debye temperature from 48 to 245 K along the [010] direction as the temperature falls below 160 K. This phase transition is evident in neutron scattering, x-ray diffraction, angle-resolved photoemission, and in the dipole active phonon modes in electron energy-loss spectroscopy. C1 Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Univ Nebraska, Ctr Mat Res & Anal, Lincoln, NE 68588 USA. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70806 USA. Oak Ridge Natl Lab, High Flux Isotope Reactor, Oak Ridge, TN 37831 USA. Russian Acad Sci, Inst Cristallog, Moscow 117333, Russia. Argonne Natl Lab, Mat Sci Div 223, Argonne, IL 60439 USA. RP Dowben, PA (reprint author), Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. RI You, Hoydoo/A-6201-2011; Ducharme, Stephen/A-1909-2009 OI You, Hoydoo/0000-0003-2996-9483; Ducharme, Stephen/0000-0003-0936-7995 NR 29 TC 32 Z9 32 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 29 PY 1999 VL 83 IS 22 BP 4562 EP 4565 DI 10.1103/PhysRevLett.83.4562 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100029 ER PT J AU Wickham, LK Schwarz, KW Stolken, JS AF Wickham, LK Schwarz, KW Stolken, JS TI Rules for forest interactions between dislocations SO PHYSICAL REVIEW LETTERS LA English DT Article ID BCC SINGLE-CRYSTALS; GLIDE PLANES; SIMULATIONS AB The dynamical interactions of dislocations existing on intersecting glide planes have been investigated using numerical simulations based on isotropic linear elastic theory. It is found that such dislocations either repel, attract and form growing junctions, or attract and form bound crossed states. Which of these occurs can be predicted from a surprisingly simple analysis of the initial configurations. The outcome is determined primarily by the angles which the dislocations initially make with the glide-plane intersection edge, and is largely independent of the initial distance between the dislocations, their initial curvature, or ambient applied stresses. The results provide a rule for dealing with forest interactions within the context of large multiple-dislocation computations. C1 IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Wickham, LK (reprint author), IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. NR 10 TC 49 Z9 50 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 NOV 29 PY 1999 VL 83 IS 22 BP 4574 EP 4577 DI 10.1103/PhysRevLett.83.4574 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100032 ER PT J AU Xu, J Mills, AP Ueda, A Henderson, DO Suzuki, R Ishibashi, S AF Xu, J Mills, AP Ueda, A Henderson, DO Suzuki, R Ishibashi, S TI Vacancy clusters on surfaces of Au nanoparticles embedded in MgO SO PHYSICAL REVIEW LETTERS LA English DT Article ID ION-IMPLANTATION; POSITRONS AB MeV implantation of gold ions into MgO(100) followed by annealing is a method to form gold nanoparticles for obtaining modified optical properties. We show from variable-energy positron spectroscopy that clusters of 2 Mg and 2 O vacancies (v(4)) are attached to the gold nanoparticle surfaces within the projected range (R-p). We also find that v(4) vacancy clusters are created at depths less than R-p, and extend into the region greater than R-p due to damage induced by knock-on collisions. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Fisk Univ, Dept Phys, Chem Phys Lab, Nashville, TN 37208 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Xu, J (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 15 TC 40 Z9 42 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 NOV 29 PY 1999 VL 83 IS 22 BP 4586 EP 4589 DI 10.1103/PhysRevLett.83.4586 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100035 ER PT J AU Woodfield, BF Wright, DA Fisher, RA Phillips, NE Tang, HY AF Woodfield, BF Wright, DA Fisher, RA Phillips, NE Tang, HY TI Superconducting-normal phase transition in (Ba1-xKx)BiO3,x=0.40, 0.47 SO PHYSICAL REVIEW LETTERS LA English DT Article ID POLYCRYSTALLINE BA0.6K0.4BIO3; HEAT AB Specific-heat measurements on (Ba1-xKx)BiO3, x = 0.40 and 0.47, 0.7 less than or equal to T less than or equal to 35 K, 0 less than or equal to H less than or equal to 9 T, have determined the coefficient (gamma) of the normal-state conduction electron specific heat, and shown well-defined specific-heat anomalies at T-c that are consistent with the value of gamma and BCS expressions. These results contradict the suggestion in a recent Letter that gamma is several orders of magnitude greater than these experimental values and that the absence of a correspondingly large specific-heat anomaly constitutes evidence that the transition is an Ehrenfest fourth-order transition. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Natl Chi Nan Univ, Dept Appl Chem, Nantou 545, Taiwan. RP Woodfield, BF (reprint author), Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. NR 13 TC 16 Z9 16 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 29 PY 1999 VL 83 IS 22 BP 4622 EP 4625 DI 10.1103/PhysRevLett.83.4622 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100044 ER PT J AU Fromer, NA Schuller, C Chemla, DS Shahbazyan, TV Perakis, IE Maranowski, K Gossard, AC AF Fromer, NA Schuller, C Chemla, DS Shahbazyan, TV Perakis, IE Maranowski, K Gossard, AC TI Electronic dephasing in the quantum Hall regime SO PHYSICAL REVIEW LETTERS LA English DT Article ID EXCITON-EXCITON CORRELATIONS; FERMI-EDGE SINGULARITY; HIGH MAGNETIC-FIELDS; TRANSFORMATION APPROACH; COLLECTIVE EXCITATIONS; SEMICONDUCTORS; SPECTROSCOPY; SCATTERING; INTEGER; SYSTEM 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 quantum Hall effect regime. With increasing magnetic field, we observe a crossover from Markovian to non-Markovian behavior, as well as large jumps in the decay time of the FWM signal at even Landau level filling factors. The main observations can be qualitatively reproduced by a model which takes into account scattering by the collective excitations of the two-dimensional electron gas. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Fromer, NA (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Perakis, Ilias/G-9186-2011 NR 30 TC 30 Z9 30 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 NOV 29 PY 1999 VL 83 IS 22 BP 4646 EP 4649 DI 10.1103/PhysRevLett.83.4646 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100050 ER PT J AU Dodge, JS Schumacher, AB Bigot, JY Chemla, DS Ingle, N Beasley, MR AF Dodge, JS Schumacher, AB Bigot, JY Chemla, DS Ingle, N Beasley, MR TI Time-resolved optical observation of spin-wave dynamics SO PHYSICAL REVIEW LETTERS LA English DT Article ID ABSORPTION AB We have created a nonequilibrium population of antiferromagnetic spin waves in Cr2O3, and characterized its dynamics, using frequency- and time-resolved nonlinear optical spectroscopy of the exciton-magnon transition. We observe a time-dependent pump-probe line shape, which results from excitation induced renormalization of the spin-wave band structure. We present a model that reproduces the basic characteristics of the data, in which we postulate the optical nonlinearity to be dominated by interactions with long-wavelength spin waves, and the dynamics to be due to spin-wave thermalization. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Karlsruhe, Inst Angew Phys, Karlsruhe, Germany. RP Dodge, JS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 14 TC 32 Z9 32 U1 4 U2 16 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 29 PY 1999 VL 83 IS 22 BP 4650 EP 4653 DI 10.1103/PhysRevLett.83.4650 PG 4 WC Physics, Multidisciplinary SC Physics GA 258YW UT WOS:000083868100051 ER PT J AU Meyer, RR Zakeri, G AF Meyer, RR Zakeri, G TI Multicoordination methods for solving convex block-angular programs SO SIAM JOURNAL ON OPTIMIZATION LA English DT Article DE large-scale optimization; decomposition; coordination; parallel computing AB Several decomposition methods are considered for solving block-angular programs (BAPs) in parallel. We present a computational comparison of synchronous multicoordination methods. The most efficient of these approaches is shown to involve an intermediate number of blocks in the coordination phase. C1 Univ Wisconsin, Dept Comp Sci, Ctr Parallel Optimizat, Madison, WI 53706 USA. Argonne Natl Labs, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Meyer, RR (reprint author), Univ Wisconsin, Dept Comp Sci, Ctr Parallel Optimizat, 1210 W Dayton St, Madison, WI 53706 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1052-6234 J9 SIAM J OPTIMIZ JI SIAM J. Optim. PD NOV 29 PY 1999 VL 10 IS 1 BP 121 EP 131 DI 10.1137/S1052623496313635 PG 11 WC Mathematics, Applied SC Mathematics GA 273JE UT WOS:000084703500008 ER PT J AU Riley, ME Ritchie, AB AF Riley, ME Ritchie, AB TI Excitation and ionization in H(1s)-H(1s) collisions SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID STATE HYDROGEN-ATOMS; CROSS-SECTIONS; IMPACT; H(2S) AB Hydrogen atom-hydrogen atom scattering is a prototype for many of the fundamental principles of atomic collisions. In this paper we present an approximation to the H + H system for scattering in the intermediate energy regime of 1-100 keV. The approximation ignores electron exchange and two-electron excitation by assuming that one of the atoms is frozen in the Is state. We allow for the evolution of the active electron by numerically solving the 3D Schrodinger equation. This approximation is by nature most appropriate for higher-energy collisions. The results capture many features of the problem and are in harmony with recent theoretical studies. Excitation and ionization cross sections are computed and compared with other theory and experiment. Neu insight into the mechanism of excitation and ionization is inferred from the solutions. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Riley, ME (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD NOV 28 PY 1999 VL 32 IS 22 BP 5279 EP 5288 DI 10.1088/0953-4075/32/22/306 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 264TC UT WOS:000084196700009 ER PT J AU Gu, MF Savin, DW Beiersdorfer, P AF Gu, MF Savin, DW Beiersdorfer, P TI Effects of electron spiralling on the anisotropy and polarization of photon emission from an electron beam ion trap SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID RAY-LINE POLARIZATION; HIGHLY-CHARGED IONS; SATELLITE LINES; SOLAR-FLARES; SPECTROSCOPY; FE; PLASMA AB We present a theoretical formalism for calculating the anisotropy and polarization of photon emission due to a spiralling beam of electrons colliding with an ensemble of atoms or ions. For an axisymmetric beam with a given velocity angular distribution, the polarization and angular distribution of the resulting radiation can be characterized by the expansion coefficients of the distribution function in terms of Legendre polynomials. We present simple expressions for dipole and quadrupole radiation and apply the results to the case of an electron beam ion trap. C1 Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. RP Gu, MF (reprint author), Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. RI Savin, Daniel/B-9576-2012 OI Savin, Daniel/0000-0002-1111-6610 NR 26 TC 24 Z9 24 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD NOV 28 PY 1999 VL 32 IS 22 BP 5371 EP 5378 DI 10.1088/0953-4075/32/22/314 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 264TC UT WOS:000084196700017 ER PT J AU Curtiss, LA Raghavachari, K Redfern, PC Baboul, AG Pople, JA AF Curtiss, LA Raghavachari, K Redfern, PC Baboul, AG Pople, JA TI Gaussian-3 theory using coupled cluster energies SO CHEMICAL PHYSICS LETTERS LA English DT Article ID QUADRATIC CONFIGURATION-INTERACTION; DENSITY-FUNCTIONAL THEORIES; COMPUTATION; GEOMETRIES; AFFINITIES; EXCHANGE; SET AB Variations of Gaussian-3 (G3) theory are presented in which the quadratic configuration interaction (QCISD(T)) energy calculation is replaced by a coupled cluster (CCSD(T)) energy calculation. This modification is made to four G3 methods that have been previously introduced. The replacement of the QCISD(T) energy by the CCSD(T) energy results in little change in the accuracy of the methods as assessed on the G2/97 test set, although the maximum deviations decrease slightly. These new G3 methods based on the coupled cluster technique are a useful alternative to the G3 methods based on quadratic configuration interaction. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Curtiss, LA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 25 TC 130 Z9 130 U1 4 U2 16 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 NOV 26 PY 1999 VL 314 IS 1-2 BP 101 EP 107 DI 10.1016/S0009-2614(99)01126-4 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 260MW UT WOS:000083955300016 ER PT J AU Herbold, CW Miller, JH Goheen, SC AF Herbold, CW Miller, JH Goheen, SC TI Cytochrome c unfolding on an anionic surface SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE ion-exchange chromatography; cytochromes; proteins ID PERFORMANCE LIQUID-CHROMATOGRAPHY; HYDROPHOBIC-INTERACTION CHROMATOGRAPHY; MONOCLONAL-ANTIBODY BINDING; EXCHANGE CHROMATOGRAPHY; STRUCTURAL-CHANGES; HYDROGEN-EXCHANGE; ALPHA-LACTALBUMIN; KINETIC MECHANISM; FIBRINOGEN; ADSORPTION AB It is now well accepted that the adsorption of proteins to solid supports sometimes involves surface-mediated unfolding. A detailed understanding of the adsorption and surface-mediated unfolding process is lacking. We selected a well studied protein, horse heart cytochrome c, and a weakly ionic support to examine some of the characteristics of protein adsorption under near-physiological conditions. We used high-performance liquid chromatography (HPLC) to investigate the effect of temperature on surface-mediated unfolding. Samples of cytochrome c were introduced to an anionic support, and a NaCl gradient was used to desorb the protein at different times and temperatures. The profiles and retention times were monitored to examine the adhesive properties of cytochrome c to the anionic support. We found that protein retention increased with time at temperatures as low as 0 degrees C, and a significant loss of cytochrome c occurred between 55 degrees C and 70 degrees C. The loss of recovery of cytochrome c indicates irreversible surface-mediated unfolding. The changes in retention time may indicate more subtle transitions, including reversible surface-mediated unfolding of cytochrome c. These results suggest that perturbations in the structure as well as unfolding of cytochrome c can be detected at a lower temperature on an anionic surface than in solution thereby acting like a catalyst for protein unfolding. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Dept Chem Sci, Richland, WA 99352 USA. RP Goheen, SC (reprint author), Pacific NW Lab, Dept Chem Sci, POB 999,MSIN P8-08, Richland, WA 99352 USA. OI Herbold, Craig/0000-0003-3479-0197 NR 34 TC 17 Z9 17 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD NOV 26 PY 1999 VL 863 IS 2 BP 137 EP 146 DI 10.1016/S0021-9673(99)00975-9 PG 10 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 258TF UT WOS:000083854700002 PM 10593494 ER PT J AU Heiken, G AF Heiken, G TI Volcanism - Will Vesuvius erupt? Three million people need to know SO SCIENCE LA English DT Editorial Material C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Heiken, G (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 6 TC 9 Z9 9 U1 1 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD NOV 26 PY 1999 VL 286 IS 5445 BP 1685 EP + DI 10.1126/science.286.5445.1685 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 259UK UT WOS:000083912200021 ER PT J AU Black, DE Peterson, LC Overpeck, JT Kaplan, A Evans, MN Kashgarian, M AF Black, DE Peterson, LC Overpeck, JT Kaplan, A Evans, MN Kashgarian, M TI Eight centuries of North Atlantic Ocean atmosphere variability SO SCIENCE LA English DT Article ID SEA-SURFACE TEMPERATURE; TROPICAL ATLANTIC; CLIMATE-CHANGE; LAST DEGLACIATION; GREENLAND SEA; UNITED-STATES; CARIACO BASIN; ICE-AGE; CIRCULATION; MODEL AB Climate in the tropical North Atlantic is controlled Largely by variations in the strength of the trade winds, the position of the Intertropical Convergence Zone, and sea surface temperatures. A high-resolution study of Caribbean sediments provides a subdecadally resolved record of tropical upwelling and trade wind Variability spanning the past 825 years. These results confirm the importance of a decadal (12- to 13-year) mode of Atlantic variability believed to be driven by coupled tropical ocean-atmosphere dynamics. Although a well-defined interdecadal mode of variability does not appear to be characteristic of the tropical Atlantic, there is evidence that century-scale variability is substantial. The tropical Atlantic may also have been involved in a major shift in Northern Hemisphere climate variability that took place about 700 years ago. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Colorado, NOAA, Paleoclimatol Program, Boulder, CO 80309 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Black, DE (reprint author), Univ S Carolina, Dept Geol Sci, Columbia, SC 29208 USA. RI Kashgarian, Michaele/E-1665-2011; OI Kashgarian, Michaele/0000-0001-7824-8418; Black, David/0000-0002-9601-6642 NR 58 TC 153 Z9 154 U1 0 U2 17 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 NOV 26 PY 1999 VL 286 IS 5445 BP 1709 EP 1713 DI 10.1126/science.286.5445.1709 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 259UK UT WOS:000083912200030 ER PT J AU Miller, WH AF Miller, WH TI Generalization of the linearized approximation to the semiclassical initial value representation for reactive flux correlation functions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT Workshop on Time-Dependent Quantum Molecular Dynamics CY FEB 13-MAR 17, 1999 CL BRIAN HEAD, UTAH SP Henry Eyring Ctr, Off Naval Res, IBM Corp, Univ Florida Quantum Theory Project, Univ Utah Ctr High Performance Comp ID TRANSITION-STATE THEORY; QUANTUM-STATISTICAL MECHANICS; COMPLEX MOLECULAR-SYSTEMS; THERMAL RATE CONSTANTS; WAVEPACKET PROPAGATION; WIGNER APPROACH; DYNAMICS METHOD; TIME; PHASE; LONG AB The semiclassical (SC) initial value representation (NR) provides a general and practical approach for including quantum effects in classical molecular dynamics simulations. The linearized approximation (LA) to the SCIVR simplifies the description much further, reducing it to the well-known classical Wigner model (i.e., a classical trajectory calculation with a Wigner distribution of initial conditions); the LA is able to describe quantum effects well for short times (t less than or similar to (h) over bar beta) but not so fur longer times. It is shown here how the full SC-IVR approach, which is able to describe quantum effects for long times, can be cast in a form very similar in structure to the LA, with specific application to flux correlation functions relevant to chemical reaction rates. This formulation may thus make it possible to carry out full SC-IVR calculations while still retaining much of the simplifying aspects of its linearized approximation. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Miller, WH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 65 TC 23 Z9 23 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD NOV 25 PY 1999 VL 103 IS 47 BP 9384 EP 9387 DI 10.1021/jp9915275 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 261LL UT WOS:000084010600002 ER PT J AU Klippenstein, SJ Harding, LB AF Klippenstein, SJ Harding, LB TI A direct transition state theory based study of methyl radical recombination kinetics SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT Workshop on Time-Dependent Quantum Molecular Dynamics CY FEB 13-MAR 17, 1999 CL BRIAN HEAD, UT SP Henry Eyring Ctr, Off Naval Res, IBM Corp, Univ Florida Quantum Theory Project, Univ Utah Ctr High Performance Comp ID POTENTIAL-ENERGY SURFACE; CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; REACTION COORDINATE; HIGH-PRESSURE; REACTION CH3+CH3->C2H6; UNIMOLECULAR REACTIONS; ASSOCIATION REACTIONS; MASTER EQUATION; RATE CONSTANTS AB Multireference configuration interaction based quantum chemical estimates are directly implemented in a variational transition state theory based analysis of the kinetics of methyl radical recombination. Separations ranging from 5.5 to 1.9 Angstrom are considered for two separate forms for the reaction coordinate. The a priori prediction for the high-pressure limit rate constant gradually decreases with increasing temperature, with a net decrease of a factor of 1.7 from 300 to 1700 K. Near room temperature, this theoretical estimate is in quantitative agreement with the experimental data. At higher temperatures, comparison between theory and experiment requires a model for the pressure dependence. Master equation calculations employing the exponential down energy transfer model suggest that the theoretical and experimental high-pressure limits gradually diverge with increasing temperature, with the former bring about 3 times greater than the latter at 1700 K. The comparison with experiment also suggests that the energy transfer coefficient, [Delta E-down], increases with increasing temperature. C1 Case Western Reserve Univ, Dept Chem, Cleveland, OH 44106 USA. Argonne Natl Lab, Theoret Chem Grp, Argonne, IL 60439 USA. RP Klippenstein, SJ (reprint author), Case Western Reserve Univ, Dept Chem, Cleveland, OH 44106 USA. OI Klippenstein, Stephen/0000-0001-6297-9187 NR 61 TC 64 Z9 64 U1 0 U2 11 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 NOV 25 PY 1999 VL 103 IS 47 BP 9388 EP 9398 DI 10.1021/jp991574x PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 261LL UT WOS:000084010600003 ER PT J AU Gray, SK Petrongolo, C Drukker, K Schatz, GC AF Gray, SK Petrongolo, C Drukker, K Schatz, GC TI Quantum wave packet study of nonadiabatic effects in O(D-1)+H-2 -> OH+H SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT Workshop on Time-Dependent Quantum Molecular Dynamics CY FEB 13-MAR 17, 1999 CL BRIAN HEAD, UTAH SP Henry Eyring Ctr, Off Naval Res, IBM Corp, Univ Florida Quantum Theory Project, Univ Utah Ctr High Performance Comp ID POTENTIAL-ENERGY SURFACE; ISOTOPIC BRANCHING RATIO; REACTIVE SCATTERING; REACTION DYNAMICS; + H-2; HD; STATES; O(D-1); DISTRIBUTIONS; ABSTRACTION AB We develop a wave packet approach to treating the electronically nonadiabatic reaction dynamics of O(D-1) + H-2 --> OH + H, allowing for the 1(1)A' and 2(1)A' potential energy surfaces and couplings, as well as the three internal nuclear coordinates. Two different systems of coupled potential energy surfaces are considered, a semiempirical diatomics-in-molecules (DIM) system due to Kuntz, Niefer, and Sloan, and a recently developed ab initio system due to Dobbyn and Knowles (DK). Nonadiabatic quantum results, with total angular momentum J = 0, are obtained and discussed. Several single surface calculations are carried out for comparison with the nonadiabatic results. Comparisons with trajectory surface hopping (TSH) calculations, and with approximate quantum calculations, are also included. The electrostatic coupling produces strong interactions between the 1(1)A' and 21A' states at short range (where these states have a conical intersection) and weak but, interestingly, nonnegligible interactions between these states at longer range. Our wave packet results show that if the initial state is chosen to be effectively the 1A' state (for which insertion to form products occurs on the adiabatic surface), then there is very little difference between the adiabatic and coupled surface results. In either case the reaction probability is a relatively flat function of energy, except for resonant oscillations. However, the 2A' reaction, dynamics (which involves a collinear transition state) is strongly perturbed by nonadiabatic effects in two distinct ways. At energies above the transition state barrier, the diabatic limit is dominant, and the 2A' reaction probability is similar to that for 1A ", which has no coupling with the other surfaces. At energies below the barrier, we find a significant component of the reaction probability from long range electronic coupling that effectively allows the wave packet to avoid having to tunnel through the barrier. This effect, which is observed on both the DIM and DK surfaces, is estimated to cause a 10% contribution to the room temperature rate constant from nonadiabatic effects. Similar results are obtained from the TSH and approximate quantum calculations. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Siena, Dept Chem, I-53100 Siena, Italy. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Gray, SK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Petrongolo, Carlo/J-8745-2016 OI Petrongolo, Carlo/0000-0002-9655-7641 NR 57 TC 66 Z9 66 U1 3 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD NOV 25 PY 1999 VL 103 IS 47 BP 9448 EP 9459 DI 10.1021/jp991601j PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 261LL UT WOS:000084010600009 ER PT J AU Faken, DB Voter, AF Freeman, DL Doll, JD AF Faken, DB Voter, AF Freeman, DL Doll, JD TI Dimensional strategies and the minimization problem: Barrier-avoiding algorithms SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT Workshop on Time-Dependent Quantum Molecular Dynamics CY FEB 13-MAR 17, 1999 CL BRIAN HEAD, UTAH SP Henry Eyring Ctr, Off Naval Res, IBM Corp, Univ Florida Quantum Theory Project, Univ Utah Ctr High Performance Comp ID MULTIPLE-MINIMA PROBLEM; LENNARD-JONES CLUSTERS; GLOBAL OPTIMIZATION; RELAXING DIMENSIONALITY; WATER CLUSTERS; DYNAMICS AB In the present paper we examine the role of dimensionality in the minimization problem. Since it has such a powerful influence on the topology of the associated potential energy landscape, we argue that it may prove useful to alter the dimensionality of the space of the original minimization problem. We explore this general idea in the context of finding the minimum energy geometries of Lennard-Jones clusters. We show that it is possible to locate barrier-free, high-dimensional pathways that connect local, three-dimensional cluster minima. The performance of the resulting, "barrier-avoiding minimization" algorithm is examined for clusters containing as many as 55 atoms. C1 Brown Univ, Dept Chem, Providence, RI 02912 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Rhode Isl, Dept Chem, Kingston, RI 02881 USA. RP Doll, JD (reprint author), Brown Univ, Dept Chem, Providence, RI 02912 USA. NR 28 TC 16 Z9 16 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD NOV 25 PY 1999 VL 103 IS 47 BP 9521 EP 9526 DI 10.1021/jp9920949 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 261LL UT WOS:000084010600019 ER PT J AU Zhu, L Seff, K Olson, DH Cohen, BJ Von Dreele, RB AF Zhu, L Seff, K Olson, DH Cohen, BJ Von Dreele, RB TI Hydronium ions in zeolites. 1. Structures of partially and fully dehydrated Na,H3O-X by X-ray and neutron diffraction SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID POWDER-DIFFRACTION; CRYSTAL-STRUCTURE; PROTON POSITIONS; HYDROLYSIS; EXCHANGE; COMPLEX; NAX AB The crystal chemistry of hydronium ions in zeolite X has been investigated by single-crystal X-ray and powder neutron diffraction. By titration of Na96Si96Al96O384 With HCl, a break in the pH was observed at 6.35, at about 33 H3O+ ions per unit cell. The structure of zeolite X in equilibrium with 0.1 M aqueous Na+ at pH 6.35 was determined by single-crystal X-ray diffraction techniques in the cubic space group Fd (3) over bar at 20 degrees C after partial dehydration (Na-60(H3O)(32)(H2O)(24)Si100Al92O384, a = 25.128(4) Angstrom) and in Fd (3) over bar m after complete dehydration (Na60H32Si100Al92O384, a = 25.101(2) Angstrom). In the partially dehydrated crystal, Na+ ions are found at three different crystallographic sites and H3O+ ions are found at two. Two different site I' positions are occupied by 16 Na+ and 16 H3O+ ions, respectively, per unit cell; a water molecule bridges between two of each in each sodalite cage to give eight near tetrahedral (H3O+)(2)H2O(Na+)(2) clusters. Two different site III' positions in the supercage are occupied by 16 Na+ and 16 H3O+ ions, respectively; a water molecule bridges between one of each to give 16 (H3O+)(H2O)(Na+) clusters. Thus a structural basis for the great selectivity of zeolite Na-X for H3O+ at near neutral pHs is demonstrated. The remaining 28 Na+ ions are at site II. In the fully dehydrated single crystal, the 60 Na+ ions are found at four crystallographic sites. Approximately 6 and 20 Na+ ions per unit cell at sites I and I', respectively, effectively fill the double six-rings. Thirty-two Na+ ions fill site II and the remaining two are at site III'. To avoid Na+ ions, at least 20 of the 32 H+ ions per unit cell should be in the supercage. Finally, neutron diffraction of Na-54(D3O)(42)Si96Al96O354. similar to 80D(2)O at 10 K revealed the structures of the 16 D3O+ ions in the sodalite units: D-O = 1.13(1) Angstrom and D-O-D = 88(1)degrees. Each deuteron hydrogen bonds to a framework oxygen atom at 1.53(1) degrees. The O ... O hydrogen-bonding distance is 2.63(1) Angstrom and the O-D ... O angle is 161 degrees. C1 Univ Hawaii Manoa, Dept Chem, Honolulu, HI 96822 USA. Univ Penn, Dept Chem Engn, Philadelphia, PA 19104 USA. Univ Calif Los Alamos Natl Lab, LANSCE, Los Alamos, NM 87545 USA. RP Seff, K (reprint author), Mobil Technol Co, POB 480, Paulsboro, NJ 08066 USA. NR 31 TC 25 Z9 25 U1 2 U2 9 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 NOV 25 PY 1999 VL 103 IS 47 BP 10365 EP 10372 DI 10.1021/jp991070z PG 8 WC Chemistry, Physical SC Chemistry GA 261LF UT WOS:000084010100007 ER PT J AU Gottesman, D Chuang, IL AF Gottesman, D Chuang, IL TI Demonstrating the viability of universal quantum computation using teleportation and single-qubit operations SO NATURE LA English DT Article ID ERROR-CORRECTION; COMPUTERS; STATE AB Algorithms such as quantum factoring(1) and quantum search(2) illustrate the great theoretical promise of quantum computers; but the practical implementation of such devices will require careful consideration of the minimum resource requirements, together with the development of procedures to overcome inevitable residual imperfections in physical systems(3-5). Many designs have been proposed, but none allow a large quantum computer to be built in the near future(6). Moreover, the known protocols for constructing reliable quantum computers from unreliable components can be complicated often requiring many operations to produce a desired transformation(3-5,7,8). Here we show how a single technique-a generalization of quantum teleportation(9)-reduces resource requirements for quantum computers and unifies known protocols for fault-tolerant quantum computation. We show that single quantum bit (qubit) operations, Bell-basis measurements and certain entangled quantum states such as Greenberger-Horne-Zeilinger (GHZ) states(10)-all of which are within the reach of current technology-are sufficient to construct a universal quantum computer. We also present systematic constructions for an infinite class of reliable quantum gates that make the design of fault-tolerant quantum computers much more straightforward and methodical. C1 IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Microsoft Corp, Res, Redmond, WA 98052 USA. RP Chuang, IL (reprint author), IBM Corp, Almaden Res Ctr, 650 Harry Rd, San Jose, CA 95120 USA. NR 23 TC 795 Z9 818 U1 4 U2 51 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 25 PY 1999 VL 402 IS 6760 BP 390 EP 393 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 259VA UT WOS:000083913600049 ER PT J AU Rutz, K Bender, M Reinhard, PG Maruhn, JA AF Rutz, K Bender, M Reinhard, PG Maruhn, JA TI Pairing gap and polarisation effects SO PHYSICS LETTERS B LA English DT Article ID MEAN-FIELD THEORY; DENSITY; MODEL AB The phenomenological adjustment of the nuclear pairing strength is usually performed with respect to the odd-even staggering of the binding energies. We find that the results strongly depend on the way in which the ground states of the odd nuclei are computed. A thorough calculation including all time-even and time-odd polarisation effects induced by the odd nucleon produces about 30% reduced odd-even staggering as compared to the standard spherical calculations in the relativistic mean-field model. The pairing strength must be enhanced by about 20% to compensate for that effect. The enhanced strength has dramatic consequences for the predicted deformation properties of the underlying mean-field models, possibly implying that new adjustments of their parameters become necessary as well. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Erlangen Nurnberg, Inst Theoret Phys 2, D-91058 Erlangen, Germany. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RP Rutz, K (reprint author), Univ Frankfurt, Inst Theoret Phys, Robert Mayer Str 10, D-60325 Frankfurt, Germany. RI Bender, Michael/B-9004-2009 NR 22 TC 39 Z9 39 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 25 PY 1999 VL 468 IS 1-2 BP 1 EP 6 DI 10.1016/S0370-2693(99)01190-9 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 260FZ UT WOS:000083940000001 ER PT J AU Brandenburg, A Burrows, PN Muller, D Oishi, N Uwer, P AF Brandenburg, A Burrows, PN Muller, D Oishi, N Uwer, P TI Measurement of the running b-quark mass using e(+)e(-) -> b(b)over-barg events SO PHYSICS LETTERS B LA English DT Article ID TO-LEADING-ORDER; JET CROSS-SECTIONS; E+E-ANNIHILATION; QCD-CORRECTIONS; ALPHA-S; GAUGE THEORIES; 3-JET; COLLIDERS; ALPHA(S)(M(Z)(2)); OBSERVABLES AB We have studied the determination of the running b-quark mass, m(b)(M-z), using Z(0) decays into 3 or more hadronic jets. We calculated the ratio of greater than or equal to 3-jet fractions in e(+)e(-)--> b (b) over bar versus e(+)e(-) --> q(i)(q) over bar(i) (q(i) = u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted m(b)(M-z) value. Our best estimate, taking correlations into account, is m(b)(M-z) = 2.56 +/- 0.27 (stat.)(-0.38)(+0.28) (syst.)(-1.48)(+0.49) (theor.) GeV/c(2). (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Rhein Westfal TH Aachen, Inst Theoret Phys, D-52056 Aachen, Germany. DESY, Theory Grp, D-22603 Hamburg, Germany. Univ Oxford, Oxford OX1 3RH, England. Stanford Linear Accelerator Ctr, Menlo Park, CA 94025 USA. Nagoya Univ, Nagoya, Aichi 464, Japan. Ctr Etud Saclay, Serv Phys Theor, F-91191 Gif Sur Yvette, France. RP Brandenburg, A (reprint author), Rhein Westfal TH Aachen, Inst Theoret Phys, D-52056 Aachen, Germany. NR 53 TC 28 Z9 28 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 25 PY 1999 VL 468 IS 1-2 BP 168 EP 177 DI 10.1016/S0370-2693(99)01194-6 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 260FZ UT WOS:000083940000025 ER PT J AU Abele, A Adomeit, J Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV 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 Hodd, C Holtzhaussen, 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 Roethel, 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 Zou, BS AF Abele, A Adomeit, J Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV 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 Hodd, C Holtzhaussen, 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 Roethel, 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 Zou, BS CA Crystal Barrel Collaboration TI Antiproton-proton annihilation at rest into K+K-pi(0) SO PHYSICS LETTERS B LA English DT Article ID (P)OVER-BAR-P ANNIHILATION; PHI; STATE; MESON AB The annihilation channel (p) over bar p --> K+K- pi(o) in liquid hydrogen at rest has been studied with the Crystal Barrel detector at LEAR. The measured branching ratio is: BR((p) over bar p --> K(+)K(-)pi(o)) = (2.37 +/- 0.15) x 10(-3). A partial wave analysis shows that this reaction is dominated by the pi(K (K) over bar)(s), KK*(892) and pi phi(1020) intermediate states. Weak signals are observed for pi a(2)(1320), pi f(2)(1270), pi f'(2)(1525) and K(K pi)(s). A satisfactory description of the Dalitz plot requires the introduction of pi(K (K) over bar)(p) intermediate states with at least one pole. (C) 1999 Published by Elsevier Science B.V. All rights reserved. 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. Univ Paris 06, 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 Calif Berkeley, LBNL, Berkeley, CA 94720 USA. RI Peters, Klaus/C-2728-2008; Meyer, Curtis/L-3488-2014 OI Peters, Klaus/0000-0001-7133-0662; Meyer, Curtis/0000-0001-7599-3973 NR 28 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 25 PY 1999 VL 468 IS 1-2 BP 178 EP 188 DI 10.1016/S0370-2693(99)01191-0 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 260FZ UT WOS:000083940000026 ER PT J AU Nash, CS Bursten, BE AF Nash, CS Bursten, BE TI Prediction of the bond lengths, vibrational frequencies, and bond dissociation energy of octahedral seaborgium hexacarbonyl, Sg(CO)(6) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID RELATIVISTIC EFFECTIVE POTENTIALS; SPIN-ORBIT OPERATORS; EFFECTIVE CORE POTENTIALS; TRANSITION-METAL; ELECTRONIC-STRUCTURE; M(CO)(6) M=CR; W(CO)(6); MO; COMPLEXES; CR(CO)(6) C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Univ Calif Lawrence Livermore Natl Lab, Glenn T Seaborg Inst Transactinium Sci, Livermore, CA 94550 USA. RP Nash, CS (reprint author), Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. NR 36 TC 15 Z9 15 U1 1 U2 10 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 NOV 24 PY 1999 VL 121 IS 46 BP 10830 EP 10831 DI 10.1021/ja9928273 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 261NB UT WOS:000084014300021 ER PT J AU Skulan, J DePaolo, DJ AF Skulan, J DePaolo, DJ TI Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ANIMALS; CYCLE; DIET AB Calcium from bone and shell is isotopically lighter than calcium of soft tissue from the same organism and isotopically lighter than source (dietary) calcium. When measured as the Ca-44/Ca-40 isotopic ratio, the total range of Variation observed is 5.5 parts per thousand, and as much as 4 parts per thousand variation is found in a single organism. The observed intraorganismal calcium isotopic Variations and the isotopic differences between tissues and diet indicate that isotopic fractionation occurs mainly as a result of mineralization. Soft tissue calcium becomes heavier or lighter than source calcium during periods when there is net gain or loss of mineral mass, respectively. These results suggest that variations of natural calcium isotope ratios in tissues may be useful for assessing the calcium and mineral balance of organisms without introducing isotopic tracers. C1 Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. Univ Calif Berkeley, Dept Integrat Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. EO Lawrence Berkeley Natl Lab, Berkeley Ctr Isotope Geochem Earth Sci Div, Berkeley, CA 94720 USA. RP Skulan, J (reprint author), Univ Wisconsin, Dept Geol & Geophys, 1215 W Dayton St, Madison, WI 53706 USA. NR 12 TC 93 Z9 99 U1 3 U2 18 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 NOV 23 PY 1999 VL 96 IS 24 BP 13709 EP 13713 DI 10.1073/pnas.96.24.13709 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 259AY UT WOS:000083872900023 PM 10570137 ER PT J AU Smith, DJ Forrest, S Ackley, DH Perelson, AS AF Smith, DJ Forrest, S Ackley, DH Perelson, AS TI Variable efficacy of repeated annual influenza vaccination SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE original antigenic sin; vaccine efficacy; repeated vaccination; antigenic distance ID VACCINES; ANTIBODY AB Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza Vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W. Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33-35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel. W. A., Gate, T. R., Couch, R. a., Huggins. L. L, & Hess, K. R. (1997) Vaccine 15, 1114-1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among Vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the Vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed Vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for Vaccination strategies for other antigenically variable pathogens that might require repeated vaccination. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Santa Fe Inst, Santa Fe, NM 87501 USA. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS-K710,T-10, Los Alamos, NM 87545 USA. FU NIAID NIH HHS [AI28433, R01 AI028433, R37 AI028433] NR 17 TC 138 Z9 140 U1 1 U2 11 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD NOV 23 PY 1999 VL 96 IS 24 BP 14001 EP 14006 DI 10.1073/pnas.96.24.14001 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 259AY UT WOS:000083872900074 PM 10570188 ER PT J AU Marina, OA Mogensen, M AF Marina, OA Mogensen, M TI High-temperature conversion of methane on a composite gadolinia-doped ceria-gold electrode SO APPLIED CATALYSIS A-GENERAL LA English DT Article DE doped ceria; electrochemical methane oxidation; methane activation; solid oxide fuel cell ID OXIDE FUEL-CELLS; SOLID ELECTROLYTE; OXIDATION; ACTIVATION; ANODES AB Direct electrochemical oxidation of methane was attempted on a gadolinia-doped ceria Ce(0.6)Gd(0.4)O(1.8) (CG4) electrode in a solid oxide fuel cell using a porous gold-CG4 mixture as current collector Gold is relatively inert to methane in contrast to other popular SOFC anode materials such as nickel and platinum. CG4 was found to exhibit a low electrocatalytic activity for methane oxidation as well as no significant reforming activity implying that the addition of an electrocatalyst or cracking catalyst to the CG4 anode is required for SOFC operating on methane. The methane conversion observed at the open-circuit potential and low anodic overpotentials seems to be due to thermal methane cracking in the gas phase and on the alumina surfaces in the cell housing. At high anodic overpotentials, at electrode potentials where oxygen evolution was expected to take place, the formation of CO(2) increased sharply. No carbon deposition was observed on the CG4 electrode after operating at 1000 degrees C during 350 h of total testing time with partial pressures of methane and steam in the range of 0.5-33 and 3-26 kPa, respectively. (C) 1999 Elsevier Science B.V, All rights reserved. C1 Riso Natl Lab, Dept Mat Res, DK-4000 Roskilde, Denmark. RP Marina, OA (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. EM Olga.Matina@pnl.gov RI Mogensen, Mogens/B-1852-2010; Mogensen, Mogens/J-6328-2013 OI Mogensen, Mogens/0000-0002-0902-0580 NR 24 TC 104 Z9 107 U1 2 U2 26 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0926-860X J9 APPL CATAL A-GEN JI Appl. Catal. A-Gen. PD NOV 22 PY 1999 VL 189 IS 1 BP 117 EP 126 DI 10.1016/S0926-860X(99)00259-8 PG 10 WC Chemistry, Physical; Environmental Sciences SC Chemistry; Environmental Sciences & Ecology GA 258XF UT WOS:000083864400012 ER PT J AU Colton, JS Yu, PY Teo, KL Weber, ER Perlin, P Grzegory, I Uchida, K AF Colton, JS Yu, PY Teo, KL Weber, ER Perlin, P Grzegory, I Uchida, K TI Selective excitation and thermal quenching of the yellow luminescence of GaN SO APPLIED PHYSICS LETTERS LA English DT Article ID LASER-DIODES; UNDOPED GAN; FILMS; PHOTOLUMINESCENCE; VACANCIES; EPITAXY AB We report the observation of narrower structures in the yellow luminescence of bulk and thin-film n-type GaN, using the technique of selective excitation. These fine structures exhibit thermal quenching associated with an activated behavior. We attribute these fine structures to phonons and electronic excitations of a shallow donor-deep acceptor complex, and determine its activation energy for delocalization. Our results suggest that in addition to distant donor-acceptor pairs, the yellow luminescence can also involve emission complexes of shallow donors and deep acceptors. (C) 1999 American Institute of Physics. [S0003-6951(99)04347-8]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Natl Univ Singapore, Dept Elect Engn, Singapore 119260, Singapore. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Polish Acad Sci, High Pressure Res Ctr, UNIPRESS, PL-01142 Warsaw, Poland. Univ Electrocommun, Dept Commun & Syst, Chofu, Tokyo 182, Japan. RP Colton, JS (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Teo, Kie Leong/B-1921-2008; OI Teo, Kie Leong/0000-0001-5073-4510 NR 26 TC 26 Z9 26 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 NOV 22 PY 1999 VL 75 IS 21 BP 3273 EP 3275 DI 10.1063/1.125322 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000011 ER PT J AU Yu, KM Walukiewicz, W Muto, S Jin, HC Abelson, JR Clerc, C Glover, CJ Ridgway, MC AF Yu, KM Walukiewicz, W Muto, S Jin, HC Abelson, JR Clerc, C Glover, CJ Ridgway, MC TI Local structures of Ga atoms in amorphous silicon and hydrogenated amorphous silicon before and after synchrotron x-ray irradiation SO APPLIED PHYSICS LETTERS LA English DT Article ID ABSORPTION FINE-STRUCTURE; ALPHA-SI; IMPURITIES AB The influence of intense x-ray irradiation on the local bonding structure of Ga dopants in both hydrogen-free (a-Si) and hydrogenated (a-Si:H) amorphous Si thin films has been studied. Prior to x-ray exposure, extended x-ray absorption fine structure measurements revealed that H reduced the static disorder around the Ga atoms in amorphous Si. Thereafter, x-ray irradiation modified the local structure in the a-Si and a-Si:H samples. The Ga coordination number increased from < 3.5 to similar to 3.80 atoms for both types of amorphous material as consistent with a greater fraction of electrically active, tetrahedrally coordinated dopant atoms. Also, greater structural disorder was observed around Ga atoms after x-ray irradiation suggesting that tetrahedrally coordinated Ga atoms were less well ordered than in threefold-coordinated sites. (C) 1999 American Institute of Physics. [S0003-6951(99)00147-3]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Div Mat Sci, Berkeley, CA 94720 USA. Nagoya Univ, Ctr Integrated Res Sci & Engn, Div Energy Sci, Chikusa Ku, Nagoya, Aichi 4648601, Japan. Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. CNRS, Ctr Spectrometrie Nucl & Spectrometrie Masse, F-91405 Orsay, France. Australian Natl Univ, Res Sch Phys Sci & Engn, Dept Elect Mat Engn, Canberra, ACT, Australia. RP Yu, KM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Div Mat Sci, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012; Ridgway, Mark/D-9626-2011; Muto, Shunsuke/G-5741-2012 OI Yu, Kin Man/0000-0003-1350-9642; Ridgway, Mark/0000-0002-0642-0108; Muto, Shunsuke/0000-0001-6275-0649 NR 19 TC 2 Z9 2 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 22 PY 1999 VL 75 IS 21 BP 3282 EP 3284 DI 10.1063/1.125325 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000014 ER PT J AU Kleinschmit, MW Yeadon, M Gibson, JM AF Kleinschmit, MW Yeadon, M Gibson, JM TI Nucleation of single-crystal CoSi2 with oxide-mediated epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON; GROWTH AB Oxide-mediated epitaxy (OME) has shown promise as a technique for the formation of epitaxial CoSi2 on a variety of Si surfaces. With our in situ ultra-high-vacuum transmission electron microscope we have studied the phase formation sequence of the deposited Co during an anneal on both clean and oxide (OME) -covered Si (001) samples. The striking difference in OME is the absence of polycrystalline CoSi2 nucleation. We discuss the origin and consequences of this observation, and report other details of the phase evolution sequence. (C) 1999 American Institute of Physics. [S0003-6951(99)01347-9]. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Inst Mat Res & Engn, Singapore 119260, Singapore. Univ Illinois, Dept Mat Sci, Urbana, IL 61801 USA. Argonne Natl Lab, Mat Res Div, Argonne, IL 60439 USA. RP Kleinschmit, MW (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Gibson, Murray/E-5855-2013 OI Gibson, Murray/0000-0002-0807-6224 NR 10 TC 23 Z9 23 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 22 PY 1999 VL 75 IS 21 BP 3288 EP 3290 DI 10.1063/1.125327 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000016 ER PT J AU Wang, XL Hoffmann, CM Hsueh, CH Sarma, G Hubbard, CR Keiser, JR AF Wang, XL Hoffmann, CM Hsueh, CH Sarma, G Hubbard, CR Keiser, JR TI Influence of residual stress on thermal expansion behavior SO APPLIED PHYSICS LETTERS LA English DT Article ID COMPOSITES AB We demonstrate that the thermal expansion behavior of a material can be substantially modified by the presence of residual stresses. In the case of a composite tube made of two layers of dissimilar steels, in situ neutron diffraction measurements revealed a significant difference in the coefficients of thermal expansion along the radial and tangential directions. It is shown that the observed difference in thermal expansion is due to the change of residual stresses with temperature. (C) 1999 American Institute of Physics. [S0003-6951(99)01647-2]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Wang, XL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011; Wang, Xun-Li/C-9636-2010 OI Wang, Xun-Li/0000-0003-4060-8777 NR 12 TC 10 Z9 10 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 22 PY 1999 VL 75 IS 21 BP 3294 EP 3296 DI 10.1063/1.125329 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000018 ER PT J AU Mao, MY Miranda, PB Kim, DS Shen, YR AF Mao, MY Miranda, PB Kim, DS Shen, YR TI Characterization of hydrogen-terminated Si(111) surfaces by sum-frequency surface vibrational spectroscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID PHONON AB Sum-frequency surface vibrational spectroscopy was used to characterize H-terminated Si(111) surfaces prepared by different methods. It was found that flash heating of a sample to 1500 K followed by H-2 dosing at 900 K yields a surface as good in quality as a wet chemically treated surface. Both surfaces are far superior than that prepared by atomic H adsorption. (C) 1999 American Institute of Physics. [S0003-6951(99)03647-5]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Mao, MY (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Miranda, Paulo/C-5933-2012; Kim, Doseok/J-8776-2013 OI Miranda, Paulo/0000-0002-2890-0268; NR 12 TC 6 Z9 6 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 22 PY 1999 VL 75 IS 21 BP 3357 EP 3359 DI 10.1063/1.125350 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000039 ER PT J AU Stadler, S Idzerda, YU Chen, Z Ogale, SB Venkatesan, T AF Stadler, S Idzerda, YU Chen, Z Ogale, SB Venkatesan, T TI The magnetism of a buried La0.7Sr0.3MnO3 interface SO APPLIED PHYSICS LETTERS LA English DT Article ID RAY-ABSORPTION-SPECTROSCOPY; THIN-FILMS; GIANT MAGNETORESISTANCE; OXYGEN DIFFUSION; SINGLE-CRYSTALS; DEVICES AB Using x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) techniques, we have investigated the electronic structure and magnetic properties of La0.7Sr0.3MnO3 (LSMO) as a function of YBa2Cu3O7-delta (YBCO) cap layer thickness. The Mn L-2,L-3 XAS and XMCD data clearly show that the magnetic properties and electronic structure of the LSMO are adversely affected by the YBCO overlayer caused by cation displacement/exchange that effectively reduces the concentration of the La atoms in the LSMO near the YBCO/LSMO interface. (C) 1999 American Institute of Physics. [S0003-6951(99)03746-8]. C1 USN, Res Lab, Mat Phys Branch, Washington, DC 20375 USA. Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. RP Stadler, S (reprint author), Brookhaven Natl Lab, NSLS Bldg 725A-U4B, Upton, NY 11973 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 30 TC 36 Z9 37 U1 5 U2 30 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 NOV 22 PY 1999 VL 75 IS 21 BP 3384 EP 3386 DI 10.1063/1.125359 PG 3 WC Physics, Applied SC Physics GA 256MA UT WOS:000083728000048 ER PT J AU Sears, TJ Johnson, PM BeeBe-Wang, J AF Sears, TJ Johnson, PM BeeBe-Wang, J TI Infrared spectrum of the CH2 out-of-plane fundamental of C2H5 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FREQUENCY-MODULATION SPECTROSCOPY; DIODE-LASER; ROTOR MODEL; ABSORPTION; ETHYL; RELAXATION; MOLECULES; ROTATION; METHYL AB Measurements of the ethyl radical -CH2 out-of-plane rocking vibrational fundamental by transient diode laser absorption spectroscopy are reported. The new data provide information on the structure of, and the barrier to internal rotation in, the radical, and how these quantities change on vibrational excitation. We find that the effective barrier decreases from approximately 17 cm(-1) in the zero point level to 10 cm(-1) in the excited vibrational level. The assigned data set now contains approximately 450 rotation-torsional transitions and has been fit to a model effective Hamiltonian. The derived molecular parameters generally reproduce the measured line positions to better than 0.01 cm(-1), but this does not approach the estimated measurement accuracy of 0.001-0.002 cm(-1). (C) 1999 American Institute of Physics. [S0021-9606(99)00144-0]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. RP Sears, TJ (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Sears, Trevor/B-5990-2013 OI Sears, Trevor/0000-0002-5559-0154 NR 26 TC 24 Z9 24 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 22 PY 1999 VL 111 IS 20 BP 9213 EP 9221 DI 10.1063/1.479835 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 253PX UT WOS:000083565900013 ER PT J AU Johnson, PM Sears, TJ AF Johnson, PM Sears, TJ TI Vibrational effects on the torsional motion of ethyl radical SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTERNAL-ROTATION AB For molecules such as ethyl radical that have a small torsional barrier, the interaction between the internal rotation and the other normal modes of the molecule can have a substantial effect on the magnitude of the barrier itself. In ethyl this is experimentally demonstrated by a large change in the torsional barrier on vibrational excitation of the methylene group inversion motion. A simple method is applied to ethyl, involving the use of electronic structure calculations to estimate both the electronic and vibrational contributions to the barrier. Good agreement is found with experimental results from the infrared spectrum of the rocking vibration of the ethyl radical. (C) 1999 American Institute of Physics. [S0021-9606(99)00244-5]. C1 SUNY Stony Brook, Dept Chem, Stony Brook, NY 11974 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Johnson, PM (reprint author), SUNY Stony Brook, Dept Chem, Stony Brook, NY 11974 USA. RI Sears, Trevor/B-5990-2013 OI Sears, Trevor/0000-0002-5559-0154 NR 10 TC 20 Z9 20 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 22 PY 1999 VL 111 IS 20 BP 9222 EP 9226 DI 10.1063/1.479836 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 253PX UT WOS:000083565900014 ER PT J AU van Mourik, T Dunning, TH AF van Mourik, T Dunning, TH TI A new ab initio potential energy curve for the helium dimer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TOTAL ATOMIZATION ENERGIES; MOLECULAR WAVE-FUNCTIONS; GAUSSIAN-BASIS SETS; PLESSET PERTURBATION-THEORY; COUPLED-CLUSTER APPROACH; QUARTIC FORCE-FIELDS; BENCHMARK CALCULATIONS; ELECTRON CORRELATION; VIBRATIONAL FREQUENCIES; VARIATIONAL CALCULATIONS AB The He-2 interaction potential has been computed employing augmented correlation-consistent basis sets and several methods beyond those commonly used to recover electron correlation, namely fifth-order Moller-Plesset perturbation theory (MP5), coupled cluster theory with full triple excitations (CCSDT), and full configuration interaction (FCI). Calculations employing the largest basis sets were not feasible for the most sophisticated methods (MP5, CCSDT, and FCI). Nonetheless, because of the rapid convergence of the calculated interaction energy differences with basis set, it was possible to obtain reliable estimates of the complete basis set MP5, CCSDT, and FCI results. The MP5 method is predicted to yield a well depth of 10.67 +/- 0.03 K at the complete basis set (CBS) limit. Thus, the accuracy of the MP5 method is comparable to that of the CCSD(T) method which yields a D-e of 10.68 +/- 0.02 K. The CCSDT method yields an estimated well depth of 10.98 +/- 0.03 K. Thus, the full effect of connected triple excitations on the He-2 well depth is 1.74 K (CCSDT-CCSD). Comparing the basis set dependence of the CCSDT and FCI well depths, the effect of connected quadruple excitations on the well depth is estimated to be just 0.015-0.020 K. Thus, the current calculations predict the FCI He-2 well depth to be 11.00 +/- 0.03 K, in excellent agreement with the recent quantum Monte Carlo calculations of Anderson [J. Chem. Phys. 99, 345 (1993)]. Taking advantage of the rapid convergence of the full triples and quadruples correlation corrections to the CCSD(T) interaction energy with basis set, an estimated FCI/CBS potential energy curve has been constructed for He-2 from 3.5 to 15.0 a(0). The resulting curve lies between the HFD-B3-FCI1 and SAPT2 semi-empirical potentials of Aziz , being closer to the SAPT2 potential. (C) 1999 American Institute of Physics. [S0021-9606(99)30144-6]. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Univ London Univ Coll, Christopher Ingold Labs, 20 Gordon St, London WC1H 0AJ, England. EM t.vanmourik@ucl.ac.uk; thom.dunning@pnl.gov RI van Mourik, Tanja/A-4007-2008 NR 79 TC 69 Z9 69 U1 2 U2 7 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 NOV 22 PY 1999 VL 111 IS 20 BP 9248 EP 9258 DI 10.1063/1.479839 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 253PX UT WOS:000083565900018 ER PT J AU Saitoh, TR Hashimoto, N Sletten, G Bark, RA Tormanen, S Bergstrom, M Furuno, K Furutaka, K Hagemann, GB Hayakawa, T Komatsubara, T Maj, A Mitarai, S Oshima, M Sampson, J Shizuma, T Varmette, PG AF Saitoh, TR Hashimoto, N Sletten, G Bark, RA Tormanen, S Bergstrom, M Furuno, K Furutaka, K Hagemann, GB Hayakawa, T Komatsubara, T Maj, A Mitarai, S Oshima, M Sampson, J Shizuma, T Varmette, PG TI Structure of the doubly odd nucleus Ta-180 description of 23 bands SO NUCLEAR PHYSICS A LA English DT Article DE Yb-176(B-11,alpha 3n)Ta-180, E=52, 55 and 57 MeV, slow beam pulsing; measured gamma-gamma coincidences, DCO ratios, alpha-gamma coincidences; Ta-180 deduced levels, K, I, pi, T-1/2,T- configurations, rotational bands; deduced B(M1)/B(E2) ratios and g(K) factors; band mixing analysis; BCS calculations with blocking; high-K isomer predicted; astrophysical consequence; intermediate states ID QUASI-PARTICLE STATES; INTRINSIC STATES; ROTATIONAL BANDS; DECAY; TRANSITIONS; SOFTNESS; ISOMER; REGION AB The structure of the doubly-odd nucleus Ta-180 has been studied by gamma-gamma coincidence measurements with a DC beam at 52 and 57 MeV and time-correlated gamma-gamma coincidence measurements with a pulsed beam at 55 MeV via the Yb-176(B-11, alpha 3n)Ta-180 reaction. In all measurements, gamma-rays were detected in coincidence with charged particles. In the time-correlated gamma-gamma coincidence measurements with a pulsed B-11 beam, three rotational bands and one octupole vibrational band have been identified above the I-pi = 15- T-1/2 = 30 mu s isomer. The configuration of three bands built on 8(+) states has been discussed by means of three-band mixing calculations. BCS calculations with blocking have been used in support of configuration assignment of four- and six-quasiparticle structures. Totally, 19 rotational bands, one beta-, one gamma- and two octupole-vibrational bands, plus one intrinsic state have been identified with two-, four- and six-quasiparticle configurations. The K values of these bands range from 0 to 19. The K-forbidden transition rates are discussed on the basis of mixing between states with widely different K-values. The BBCS calculations predict a K-pi = 22(-) isomer not identified experimentally in this nor in previous works. A search for specific intermediate states which could explain the transformation from K-pi = 9(-) to 1(+) during the astrophysical s- and r- processes was negative. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Univ Tsukuba, Dept Phys, Ibaraki, Osaka, Japan. Univ Tsukuba, Tandem Accelerator Ctr, Ibaraki, Osaka, Japan. Japan Atom Energy Res Inst, Ibaraki, Osaka, Japan. Henryk Niewodniczanski Inst Nucl Phys, Krakow, Poland. Kyushu Univ, Dept Phys, Fukuoka 812, Japan. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 3BX, Merseyside, England. RP Saitoh, TR (reprint author), Brookhaven Natl Lab, Phys Dept Bldg 510A, Upton, NY 11973 USA. RI Sampson, Janet/G-4960-2013; Hayakawa, Takehito/K-8478-2015 NR 34 TC 28 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD NOV 22 PY 1999 VL 660 IS 2 BP 121 EP 170 DI 10.1016/S0375-9474(99)00356-5 PG 50 WC Physics, Nuclear SC Physics GA 272EM UT WOS:000084637600001 ER PT J AU Saitoh, TR Saitoh-Hashimoto, N Sletten, G Bark, RA Bergstrom, M Regan, P Tormanen, S Varmette, PG Walker, PM AF Saitoh, TR Saitoh-Hashimoto, N Sletten, G Bark, RA Bergstrom, M Regan, P Tormanen, S Varmette, PG Walker, PM TI Collective and intrinsic structures in W-183 SO NUCLEAR PHYSICS A LA English DT Article DE Yb-176(C-14,alpha 3n)W-183 E=68 MeV, slow beam pulsing; measured gamma-gamma coincidences, DCO ratios, alpha-gamma coincidences; W-183 deduced levels, K, I, pi, T-1/2,T- configurations, rotational bands; deduced B(M1)/B(E2) ratios and g(K) factors; BCS calculations with blocking ID STATES; SPECTROSCOPY; TRANSITIONS AB The structure of W-183 has been studied by employing the Yb-176(C-14, alpha 3n) reaction at 68 MeV. Five previously known rotational structure with one-quasiparticle configurations have been extended to higher spin states, and five new rotational bands with three- and five-quasiparticle configurations and a gamma-vibration of a one-quasiparticle structure have been newly identified. In the nu 7/2(-)[503] and nu 11/2(+)[615] rotational structures, a signal of an admixture of an octupole vibrational structure has been observed in their in-band B(M1)/B(E2) ratios and g(K) factors. In the K-pi = 19(-) rotational band, a Coriolis effect on the nu 1/2(-)[510] neutron has been identified. In all, 17 K-forbidden transitions have been observed. Energies of intrinsic states below 4 MeV have been calculated based on the Blocked BCS theory, and they are used in support of the configuration assignments. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Univ Tsukuba, Dept Phys, Ibaraki, Osaka, Japan. Univ Tsukuba, Tandem Accelerator Ctr, Ibaraki, Osaka, Japan. Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. RP Saitoh, TR (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 21 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD NOV 22 PY 1999 VL 660 IS 2 BP 171 EP 196 DI 10.1016/S0375-9474(99)00381-4 PG 26 WC Physics, Nuclear SC Physics GA 272EM UT WOS:000084637600002 ER PT J AU Pesiri, DR Morita, DK Walker, T Tumas, W AF Pesiri, DR Morita, DK Walker, T Tumas, W TI Vanadium-catalyzed epoxidations of olefinic alcohols in liquid carbon dioxide SO ORGANOMETALLICS LA English DT Article ID ACYCLIC HOMOALLYLIC ALCOHOLS; TERT-BUTYL HYDROPEROXIDE; ASYMMETRIC EPOXIDATION; OXIDATION; MECHANISM; MOLYBDENUM; PEROXIDES; COMPLEXES; KINETICS; STATE AB The selective epoxidation of olefinic alcohols with t-BuOOH in the presence of vanadium catalysts proceeds in liquid carbon dioxide with high conversions and selectivities. Rates measured in liquid CO2 for the oxovanadium(V) triisopropoxide catalyzed epoxidation of allylic and homoallylic alcohols using tert-butyl hydroperoxide are comparable to those measured in methylene chloride, toluene, and n-hexane. The reactivity of the vanadium(IV) bis(acetylacetonato) oxide catalyst in liquid CO2 was found to be substantially lower than in organic solvents, presumably due to its low solubility in CO2. Highly fluorinated acac-type ligands increased the catalytic reactivity of VO(acac)(2)-catalyzed epoxidations by enhancing catalyst precursor solubility. Heterogeneous epoxidation reactions were also carried out in liquid CO2 using vanadium complexes supported on cation-exchange polymers. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Tumas, W (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS-J514, Los Alamos, NM 87545 USA. NR 43 TC 17 Z9 17 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD NOV 22 PY 1999 VL 18 IS 24 BP 4916 EP 4924 DI 10.1021/om990467m PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 259FR UT WOS:000083884300006 ER PT J AU Wang, WD Espenson, JH AF Wang, WD Espenson, JH TI Metathesis reactions of tris (adamantylimido) methylrhenium and aldehydes and imines SO ORGANOMETALLICS LA English DT Article ID MAIN-GROUP ELEMENTS; TRANSITION-METALS; IMIDO COMPLEXES; MULTIPLE BONDS; NITRENE TRANSFER; REACTIVITY; RHENIUM; OXO; AZIRIDINATION; MECHANISM AB The tris(imido)methylrhenium compound CH3Re(NAd)(3) (Ad = 1-adamantyl) was prepared and characterized. It reacts with aromatic aldehydes ArCHO forming the imines ArCH=NAd. The reaction occurs in three stages, during which CH3Re(NAd)(2)O and CH3Re(NAd)O-2 could be detected. In the third and slowest stage CH3ReO3 (MTO) was formed, eventually in quantitative yield. The second-order rate constant for PhCHO in C6D6 at 298 K is 1.4 x 10(-4) L mol(-1) s(-1). Electron-donating substituents at the para-position of ArCHO cause a significant diminution in rate. Treated by the Hammett equation, the reaction constant is rho = +0.90. The reactions between CH3Re(NAd)(3) and linear aliphatic aldehydes occur much faster than do reactions of nonlinear aliphatic or aromatic aldehydes, indicating an important steric effect. Ketones do not react. The imidorhenium complex evidently undergoes a metathesis reaction with the aldehyde. Analogously, CH3Re(NAd)(3) reacts with imines. Imine-imine metathesis is catalyzed by MTO homogeneously and by MTO supported on Nb2O5. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 36 TC 26 Z9 26 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD NOV 22 PY 1999 VL 18 IS 24 BP 5170 EP 5175 DI 10.1021/om990462p PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 259FR UT WOS:000083884300037 ER PT J AU Schenkel, T Barnes, AV Niedermayr, TR Hattass, M Newman, MW Machicoane, GA McDonald, JW Hamza, AV Schneider, DH AF Schenkel, T Barnes, AV Niedermayr, TR Hattass, M Newman, MW Machicoane, GA McDonald, JW Hamza, AV Schneider, DH TI Deposition of potential energy in solids by slow, highly charged ions SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-EMISSION; SILICON; SURFACE; EXCITATION; SIO2; DETECTORS; TRANSPORT; YIELDS; IMPACT; LIMIT AB We have measured the deposition of potential energy of slow (similar to 6 x 10(5) m/s), highly charged ions in solids with an ion implanted silicon detector. A large fraction (about 35% or 60 keV) of the potential energy dissipated by Au69+ ions can be traced in electronic excitations deep (>50 nm) inside the solid. In contrast, only about 10% of the potential energy has been accounted for in measurements of emitted secondary particles. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Schenkel, T (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 32 TC 41 Z9 44 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 22 PY 1999 VL 83 IS 21 BP 4273 EP 4276 DI 10.1103/PhysRevLett.83.4273 PG 4 WC Physics, Multidisciplinary SC Physics GA 256UV UT WOS:000083745600013 ER PT J AU Madsen, N Bowe, P Drewsen, M Hornekaer, LH Kjaergaard, N Labrador, A Nielsen, JS Schiffer, JP Shi, P Hangst, JS AF Madsen, N Bowe, P Drewsen, M Hornekaer, LH Kjaergaard, N Labrador, A Nielsen, JS Schiffer, JP Shi, P Hangst, JS TI Density limitations in a stored laser-cooled ion beam SO PHYSICAL REVIEW LETTERS LA English DT Article ID STORAGE-RING; SPACE-CHARGE; SYNCHROTRON AB We present a new technique for transverse beam profile diagnostics of a stored ion beam, imaging the fluorescence light from a laser-excited ion beam onto a high resolution charge-coupled device detector. This technique has much higher sensitivity and spatial resolution than conventional techniques. Using this method we have obtained evidence for space-charge-dominated behavior of a stored, laser-cooled beam of Mg-24(+) ions. However, the transverse size of the longitudinally cooled beam is larger than that expected for a space-charge limited beam. This seems to confirm expectations from molecular dynamics simulations, showing that to reach a crystalline beam, other techniques have to be applied. C1 Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Chicago, Chicago, IL 60637 USA. RP Madsen, N (reprint author), CERN, CH-1211 Geneva 23, Switzerland. RI Kjaergaard, Niels/B-1806-2008; Madsen, Niels/G-3548-2013 OI Kjaergaard, Niels/0000-0002-7830-9468; Madsen, Niels/0000-0002-7372-0784 NR 20 TC 22 Z9 22 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 NOV 22 PY 1999 VL 83 IS 21 BP 4301 EP 4304 DI 10.1103/PhysRevLett.83.4301 PG 4 WC Physics, Multidisciplinary SC Physics GA 256UV UT WOS:000083745600020 ER PT J AU Terry, RE Davis, J Deeney, C Velikovich, AL AF Terry, RE Davis, J Deeney, C Velikovich, AL TI Current switching and mass interpenetration offer enhanced power from nested-array Z pinches SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY POWER AB Nested-array Z pinches are concentric, two layer wire assemblies-an exterior (driver) layer and an interior (target) layer. On the 20-MA Z accelerator they produce record-high x-ray power, 40% over a single array, but the mechanism of power enhancement remains unclear. The observed kinematics of the nested arrays is best described by a model that allows the drive mass to penetrate the target mass. At assembly the load filament's mutual inductance requires current to switch rapidly from the drive to the target array. C1 USN, Radiat Hydrodynam Branch, Div Plasma Phys, Res Lab, Washington, DC 20375 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Terry, RE (reprint author), USN, Radiat Hydrodynam Branch, Div Plasma Phys, Res Lab, Washington, DC 20375 USA. RI Velikovich, Alexander/B-1113-2009 NR 14 TC 30 Z9 31 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 NOV 22 PY 1999 VL 83 IS 21 BP 4305 EP 4308 DI 10.1103/PhysRevLett.83.4305 PG 4 WC Physics, Multidisciplinary SC Physics GA 256UV UT WOS:000083745600021 ER PT J AU Sadigh, B Lenosky, TJ Theiss, SK Caturla, MJ de la Rubia, TD Foad, MA AF Sadigh, B Lenosky, TJ Theiss, SK Caturla, MJ de la Rubia, TD Foad, MA TI Mechanism of boron diffusion in silicon: An ab initio and kinetic Monte Carlo study SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; INTERSTITIAL BORON; IMPURITY DIFFUSION; POINT-DEFECTS; PSEUDOPOTENTIALS; SYSTEM AB An exhaustive first-principles study of the energetics of B-Si interstitial complexes of various configurations and charge states is used to elucidate the diffusion mechanism of B in Si. Total energy calculations and molecular dynamics simulations show that B diffuses by an interstitialcy mechanism. Substitutional B captures a Si interstitial with a binding energy of 0.90 eV. This complex is itself a fast diffuser, with no need to first "kick out" the B into an interstitial channel. The migration barrier is about 0.68 eV. Kinetic Monte Carlo simulations confirm that this mechanism leads to a decrease in the diffusion length with increasing temperature, as observed experimentally. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Appl Mat Corp, Implant Div, Santa Clara, CA 95054 USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Caturla, Maria /D-6241-2012 OI Caturla, Maria /0000-0002-4809-6553 NR 30 TC 146 Z9 149 U1 5 U2 36 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 NOV 22 PY 1999 VL 83 IS 21 BP 4341 EP 4344 DI 10.1103/PhysRevLett.83.4341 PG 4 WC Physics, Multidisciplinary SC Physics GA 256UV UT WOS:000083745600030 ER PT J AU Vasiliu-Doloc, L Rosenkranz, S Osborn, R Sinha, SK Lynn, JW Mesot, J Seeck, OH Preosti, G Fedro, AJ Mitchell, JF AF Vasiliu-Doloc, L Rosenkranz, S Osborn, R Sinha, SK Lynn, JW Mesot, J Seeck, OH Preosti, G Fedro, AJ Mitchell, JF TI Charge melting and polaron collapse in La1.2Sr1.8Mn2O7 SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-SCATTERING; MAGNETORESISTANCE; LA1-XSRXMNO3; DISTORTION; STRIPES AB X-ray and neutron scattering measurements directly demonstrate the existence of polarons in the paramagnetic phase of optimally doped colossal magnetoresistive oxides. The polarons exhibit short-range correlations that grow with decreasing temperature, but disappear abruptly at the ferromagnetic transition because of the sudden charge delocalization. The "melting" of the charge ordering as we cool through T-C occurs with the collapse of the quasistatic polaron scattering, and provides important new insights into the relation of polarons to colossal magnetoresistance. C1 No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Vasiliu-Doloc, L (reprint author), No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383 NR 23 TC 144 Z9 144 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 22 PY 1999 VL 83 IS 21 BP 4393 EP 4396 DI 10.1103/PhysRevLett.83.4393 PG 4 WC Physics, Multidisciplinary SC Physics GA 256UV UT WOS:000083745600043 ER PT J AU Armstrong, TA Barish, KN Batsouli, S Bennett, MJ Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, RR De Cataldo, G Dee, P Diebold, GE Dover, CB Ewell, LA Emmet, W Fachini, P Fadem, B Finch, LE George, NK Giglietto, N Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, RA Huang, HZ Jaradat, H Kim, B Kumar, BS Lajoie, JG Lainis, T Lewis, RA Li, Q Li, Y Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Petridis, A Pless, IA Pope, JK Porile, NT Pruneau, C Rabin, MSZ Reid, JD Rimai, A Riso, J Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Skank, H Slaughter, AJ Sleage, G Smith, GA Spinelli, P Srivastava, BK Tincknell, ML Toothacker, WS Van Buren, G Wilson, WK Wohn, FK Wolin, EJ Xu, Z Zhao, K AF Armstrong, TA Barish, KN Batsouli, S Bennett, MJ Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, RR De Cataldo, G Dee, P Diebold, GE Dover, CB Ewell, LA Emmet, W Fachini, P Fadem, B Finch, LE George, NK Giglietto, N Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, RA Huang, HZ Jaradat, H Kim, B Kumar, BS Lajoie, JG Lainis, T Lewis, RA Li, Q Li, Y Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Petridis, A Pless, IA Pope, JK Porile, NT Pruneau, C Rabin, MSZ Reid, JD Rimai, A Riso, J Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Skank, H Slaughter, AJ Sleage, G Smith, GA Spinelli, P Srivastava, BK Tincknell, ML Toothacker, WS Van Buren, G Wilson, WK Wohn, FK Wolin, EJ Xu, Z Zhao, K CA BNL E864 Collaboration TI A spectrometer for study of high mass objects created in relativistic heavy ion reactions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE spectrometer; calorimeter; heavy ions; tracking; trigger ID SCINTILLATING-FIBER CALORIMETER; STRANGE QUARK MATTER; COLLISIONS; SEARCH AB Experiment E864 at the Brookhaven AGS accelerator uses a high sensitivity, large acceptance spectrometer, designed to search for strangelets and other novel forms of matter produced in high-energy heavy ion collisions. The spectrometer has excellent acceptance and rate capabilities for measuring the production properties of known particles and nuclei such as (p) over bar, (d) over bar and He-6. The experiment uses a magnetic spectrometer and employs redundant time of flight and position detectors and a hadronic calorimeter. In this paper we describe the design and performance of the spectrometer. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames, IA 50011 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Yale Univ, New Haven, CT 06520 USA. Wayne State Univ, Detroit, MI 48201 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Bari, Ist Nazl Fis Nucl, Bari, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. Vanderbilt Univ, Nashville, TN 37235 USA. MIT, Cambridge, MA 02139 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. US Mil Acad, W Point, NY 10996 USA. Univ Massachusetts, Amherst, MA 01003 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Hill, JC (reprint author), Iowa State Univ, Ames, IA 50011 USA. RI giglietto, nicola/I-8951-2012 OI giglietto, nicola/0000-0002-9021-2888 NR 16 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD NOV 21 PY 1999 VL 437 IS 2-3 BP 222 EP 246 DI 10.1016/S0168-9002(99)00679-8 PG 25 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 257PJ UT WOS:000083790400006 ER PT J AU Huber, JS Moses, WW Andreaco, MS Loope, M Melcher, CL Nutt, R AF Huber, JS Moses, WW Andreaco, MS Loope, M Melcher, CL Nutt, R TI Geometry and surface treatment dependence of the light collection from LSO crystals SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SCINTILLATION LIGHT; DETECTOR AB We study the relative light collection efficiency for narrow LSO crystals as a function of surface finish and geometry. We explore both a specular and diffuse surface reflector finish, using LSO crystals that are either polished or etched. The crystals have a square cross-section with widths of 1.8, 2.2, 2.5, or 2.6 mm and lengths of 10, 20 or 30 mm. When optically coupled to a PMT on a square end and wrapped with Tenon on 5 sides, we excite them at 5 mm incremental depths with 511 keV photons and measure the photopeak position. The light collection is characterized by a maximum output (based on the photopeak position when excited at the PMT end) and a depth-dependent loss factor. Both the maximum output and loss factor are effectively independent of width, and the maximum output is only weakly dependent on length (6696 +/- 612, 5796 +/- 432, and 5328 +/- 288 photons for 10, 20, and 30 mm lengths). The loss factor is effectively independent of length, with a 0, 18, 27, and 22% reduction at excitation depths of 0, 10, 20, and 30 mm. The light collection is only weakly dependent on surface finish if it is polished or etched beyond a minimum time. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. CTI Inc, Knoxville, TN 37932 USA. RP Huber, JS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Mail Stop 55-121,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM jshuber@lbl.gov RI Melcher, Charles/E-9818-2012 OI Melcher, Charles/0000-0002-4586-4764 NR 13 TC 38 Z9 39 U1 1 U2 7 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 NOV 21 PY 1999 VL 437 IS 2-3 BP 374 EP 380 DI 10.1016/S0168-9002(99)00766-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 257PJ UT WOS:000083790400017 ER PT J AU Rudy, CR AF Rudy, CR TI Correlative assay of uranium with calorimetry, neutron counting, and mass spectrometry data SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A methodology has been developed for assaying unirradiated enriched uranium that uses calorimetry, passive neutron counting, and historical mass spectrometry data. Calorimetry can be used to measure the thermal power of bulk uranium enriched in the isotope U-235 and neutron counting can be used to determine its spontaneous-fission neutron emission rate. The thermal power and neutron-emission properties of uranium change in a regular way with increasing U-235 enrichment that can be quantified using mass spectrometry data. The measured ratio of the thermal power and spontaneous neutron fission rate can be used to determine the U-235 enrichment and the total mass of the U-234, U-235 and U-238 isotopes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Grp NIS5, Los Alamos, NM 87545 USA. RP Rudy, CR (reprint author), Univ Calif Los Alamos Natl Lab, Grp NIS5, MS E540, Los Alamos, NM 87545 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD NOV 21 PY 1999 VL 437 IS 2-3 BP 501 EP 507 DI 10.1016/S0168-9002(99)00775-5 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 257PJ UT WOS:000083790400029 ER PT J AU Hwu, Y Tsai, WL Lai, B Mancini, DC Je, JH Noh, DY Youn, HS Hwang, CS Cerrina, F Swiech, W Bertolo, M Tromba, G Margaritondo, G AF Hwu, Y Tsai, WL Lai, B Mancini, DC Je, JH Noh, DY Youn, HS Hwang, CS Cerrina, F Swiech, W Bertolo, M Tromba, G Margaritondo, G TI Use of photoelectron microscopes as X-ray detectors for imaging and other applications SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SYNCHROTRON-RADIATION; SPECTROMICROSCOPY; CONTRAST; RESOLUTION; MEPHISTO; SURFACES AB We demonstrate with practical tests that a photoelectron emission microscope (PEEM) can be advantageously used as a high-lateral-resolution detector of X-rays. The advantages of this approach are discussed, in particular for coherence-based techniques. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Acad Sinica, Inst Phys, Taipei, Taiwan. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Pohang Univ Sci & Technol, Dept Mat Sci & Engn, Pohang, South Korea. Kwangju Inst Sci & Technol, Dept Mat Sci & Engn, Kwangju, South Korea. Kwangju Inst Sci & Technol, Ctr Elect Mat Res, Kwangju, South Korea. Pohang Univ Sci & Technol, Pohang Accelerator Lab, Pohang, South Korea. Synchrotron Radiat Res Ctr, Hsinchu, Taiwan. Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA. Sincrotrone Trieste, I-34012 Trieste, Italy. Ecole Polytech Fed Lausanne, Inst Phys Appl, CH-1015 Lausanne, Switzerland. RP Hwu, Y (reprint author), Acad Sinica, Inst Phys, Taipei, Taiwan. RI Margaritondo, Giorgio/B-1367-2008 NR 24 TC 9 Z9 9 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 NOV 21 PY 1999 VL 437 IS 2-3 BP 516 EP 520 DI 10.1016/S0168-9002(99)00757-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 257PJ UT WOS:000083790400031 ER PT J AU Cote, P Mateo, M Olszewski, EW Cook, KH AF Cote, P Mateo, M Olszewski, EW Cook, KH TI Internal kinematics of the Andromeda II dwarf spheroidal galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : individual (Andromeda II); galaxies : kinematics and dynamics ID TO-LIGHT RATIOS; URSA-MINOR; DARK-MATTER; SATELLITE GALAXIES; RADIAL-VELOCITIES; MASS; DRACO; SPECTROSCOPY; COMPANIONS; CLUSTERS AB The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of similar or equal to 2 km s(-1) for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And IT). We find a weighted mean radial velocity of (v) over bar(r), = -188 +/- 3 km s(-1) and a central velocity dispersion of sigma(0) = 9.3(-2.6)(+2.7) km s(-1). There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/L(V) = 20.9(-10.1)(+13.9) M(circle dot)/L(V,circle dot). This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II. C1 CALTECH, Pasadena, CA 91125 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Cote, P (reprint author), CALTECH, Mail Stop 105-24, Pasadena, CA 91125 USA. NR 33 TC 48 Z9 48 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 1999 VL 526 IS 1 BP 147 EP 151 DI 10.1086/307999 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258XA UT WOS:000083863900012 ER PT J AU Feldmeier, A Shlosman, I Vitello, P AF Feldmeier, A Shlosman, I Vitello, P TI Dynamics of line-driven winds from disks in cataclysmic variables. II. Mass-loss rates and velocity laws SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; novae, cataclysmic variables; stars : mass loss; stars : winds, outflows ID HOT LUMINOUS STARS; HOPKINS ULTRAVIOLET TELESCOPE; ACCRETION DISKS; STELLAR WINDS; Z-CAMELOPARDALIS; B-STARS; EMISSION; SPECTROSCOPY; DIAGNOSTICS; SPECTRUM AB We analyze the dynamics of two-dimensional stationary, line-driven winds from accretion disks in cataclysmic variable (CV) stars by generalizing the formalism of Castor, Abbott, and Klein (CAK) for O stars. In Paper I, we solved the wind Euler equation, derived its two eigenvalues, and addressed the solution topology and wind geometry. Here, we focus on mass-loss rates and velocity laws of the wind. We find that disk winds, even in luminous nova-like variables, have low optical depth, even in the strongest driving lines. This suggests that thick-to-thin transitions in these lines occur in the wind. For disks with a realistic radial temperature law, the mass loss is dominated by gas emanating from the inner decade in radius. The total mass-loss rate associated with the wind from a disk of luminosity 10 L. is similar to 10(-1)2 M. yr(-1), or 10(-4) of the mass accretion rate. This is 1 order of magnitude below the lower limit obtained from fitting P Cygni line profiles using kinematical wind models when the Lyman continuum is suppressed. The difficulties associated with such small mass-loss rates for line-driven winds from disks in CVs are principal and confirm our previous work on this subject. We conjecture that this issue may be resolved by detailed non-LTE calculations of the CAK line force within the context of CV disk winds and/or by better accounting for the disk energy distribution and wind ionization structure. We find that the wind velocity profile is well approximated by the empirical law used in kinematical modeling. The acceleration length scale is given by the footpoint radius of the wind streamline in the disk. This suggests an upper limit of similar to 10r(wd) to the acceleration scale, which is smaller by factor of a few as compared with values derived from line fitting. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Feldmeier, A (reprint author), Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. NR 33 TC 15 Z9 15 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 NOV 20 PY 1999 VL 526 IS 1 BP 357 EP 364 DI 10.1086/307977 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258XA UT WOS:000083863900031 ER PT J AU Wolff, MT Wood, KS Imamura, JN Middleditch, J Steiman-Cameron, TY AF Wolff, MT Wood, KS Imamura, JN Middleditch, J Steiman-Cameron, TY TI X-ray and optical observations of BL Hydri SO ASTROPHYSICAL JOURNAL LA English DT Article DE novae, cataclysmic variables; radiation mechanisms : nonthermal stars : individual (BL Hydri); white dwarfs; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; MAGNETIC WHITE-DWARFS; RADIATIVE SHOCKS; TIMING EXPLORER; AM-HER; EMISSION; HYI; POLARIMETRY; PERFORMANCE; SEARCH AB We acquired hard X-ray and unfiltered optical photometric data of the AM Herculis system BL Hydri. The X-ray data were obtained using the Proportional Counter Array detector of the Rossi X-Ray Timing Explorer satellite on 1997 October 17. The optical data were obtained using the 1.5 m telescope of the Cerro Tololo Inter-American Observatory on 1997 September 24. At the time of our observations, BL Hyi was in an unusual high-luminosity state with average visual magnitude m(v) approximate to 14.4 and orbital phase-averaged 2-10 keV X-ray flux approximate to 1.5 x 10(-11) ergs cm(-2) s(-1), roughly 50% larger than had been seen previously. The X-ray light curves suggested that two accretion poles were active. The primary X-ray emission region was extended, covering similar to 45 degrees in longitude on the white dwarf, while the secondary X-ray emission region was consistent with a point source with flux similar to 33% that of the primary region. The X-ray spectra were well fitted by absorbed bremsstrahlung with Gaussian emission-line models; and absorbed power law with Gaussian emission-line models. For the thermal models, the X-ray spectra were consistent with kT(X) approximate to 11 keV and an emission line at E approximate to 6.7-6.8 keV with equivalent width EW = 0.86-1.2 keV. The absorbed power-law models had slope alpha approximate to 2.1 and an emission line at E = 6.7-6.8 keV with EW = 1.1-1.5 keV. The optical data showed, 2.7% +/- 0.2% rms quasi-periodic oscillations (QPOs) over the frequency range 0.2-0.8 Hz modulated strongly on the orbital period suggesting that the QPOs were connected with the dominant accretion hot spot. We did not did corresponding QPOs in the X-ray emission for an upper limit of 20% rms. There were no detections of other short-period QPOs or coherent features in either the optical or the X-ray data. The X-ray and optical data were consistent with a radiative shock model. Based primarily on the X-ray continuum and line spectrum, we infer that the mass of the white dwarf in the BL Hyi system is 0.3-0.7 M., depending on the relative cyclotron and hard X-ray luminosities. C1 USN, Res Lab, Washington, DC 20375 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Univ Oregon, Inst Theoret Sci, Eugene, OR 97403 USA. Univ Calif Los Alamos Natl Lab, Comp Informat & Commun Div, Los Alamos, NM 87545 USA. Indiana Univ, Dept Astron, Bloomington, IN 47405 USA. RP Wolff, MT (reprint author), USN, Res Lab, Code 7621-9, Washington, DC 20375 USA. NR 30 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 1999 VL 526 IS 1 BP 435 EP 444 DI 10.1086/307982 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258XA UT WOS:000083863900037 ER PT J AU Nayfonov, A Dappen, W Hummer, DG Mihalas, D AF Nayfonov, A Dappen, W Hummer, DG Mihalas, D TI The MHD equation of state with post-Holtsmark microfield distributions SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; equation of state; MHD; stars : atmospheres ID LARKIN PARTITION-FUNCTION; STRONGLY COUPLED PLASMAS; STELLAR ENVELOPES; SOLAR OSCILLATIONS; OPAL; FREQUENCIES; QUANTITIES; MODEL AB The Mihalas-Hummer-Dappen (MHD) equation of state is a part of the Opacity Project (OP), where it mainly provides ionization equilibria and level populations of a large number of astrophysically relevant species. Its basic concept is the idea of perturbed atomic and ionic states. At high densities, when many-body effects become dominant, the concept of perturbed atoms loses its sense. For that reason, the MHD equation of state was originally restricted to the plasma of stellar envelopes, that is, to relatively moderate densities, which should not exceed rho < 10(-2) g cm(-3). However, helioseismological analysis has demonstrated that this restriction is much too conservative. The principal feature of the original Hummer & Mihalas paper is an expression for the destruction probability of a bound state (ground state or excited) of a species (atomic or ionic), linked to the mean electric microfield of the plasma. Hummer dr Mihalas assumed, for convenience, a simplified form of the Holtsmark microfield for randomly distributed ions. An improved MHD equation of state (Q-MHD) is introduced. It is based on a more realistic microfield distribution that includes plasma correlations. Comparison with an alternative post-Holtsmark formalism (APEX) is made, and good agreement is shown. There is a clear signature of the choice of the microfield distribution in the adiabatic index gamma(1), which makes it accessible to present-day helioseismological analysis. However, since these thermodynamic effects of the microfield distribution are quite small, it also follows that the approximations chosen in the original MHD equation of state were reasonable. A particular feature of the original MHD papers was an explicit list of the adopted free energy and its first- and second-order analytical derivatives. The corresponding Q-MHD quantities are given in the Appendix. C1 Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Aarhus Univ, Inst Phys & Astron, Theoret Astrophys Ctr, DK-8000 Aarhus, Denmark. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nayfonov, A (reprint author), Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. NR 43 TC 36 Z9 36 U1 1 U2 5 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 NOV 20 PY 1999 VL 526 IS 1 BP 451 EP 464 DI 10.1086/307972 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258XA UT WOS:000083863900039 ER PT J AU Liu, WH Schultz, DR AF Liu, WH Schultz, DR TI Jovian X-ray aurora and energetic oxygen ion precipitation SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; planets and satellites : individual (Jupiter); X-rays : general ID ELECTRON-ELECTRON INTERACTION; EXTREME ULTRAVIOLET OBSERVATIONS; DIFFERENTIAL CROSS-SECTIONS; FULLY STRIPPED IONS; MOLECULAR-HYDROGEN; ANGULAR-DISTRIBUTIONS; INTERMEDIATE ENERGIES; COLLISIONS; JUPITER; IONIZATION AB The X-ray line spectra of highly charged oxygen ions excited by charge transfer interaction with the molecular hydrogen in the auroral atmosphere of Jupiter are calculated. The calculations utilize our calculated cross sections of state-selective charge transfer and the available cross-section data of ionization and stripping. Comparison of these spectra with high-resolution spectral observations may provide a sensitive probe of the characteristics of the heavy ions precipitating into the Jovian auroral atmosphere. On the basis of the much higher X-ray efficiency of heavy ions than of electrons, it is concluded that the Jovian aurora may be accounted for by a combination of energetic heavy-ion precipitation and energetic electron precipitation, which produces the auroral X-ray and ultraviolet emissions, respectively. 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 42 TC 28 Z9 28 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 1999 VL 526 IS 1 BP 538 EP 543 DI 10.1086/307994 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258XA UT WOS:000083863900046 ER PT J AU Uraltsev, N AF Uraltsev, N TI Theoretical uncertainties in Gamma(sl)(b -> u) SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Workshop on the Derivation of V(cb) and V(mu-b): Experimental Status and Theory Uncertainties CY MAY 28-JUN 02, 1999 CL CERN, GENEVA, SWITZERLAND HO CERN ID OPERATOR PRODUCT EXPANSION; HEAVY FLAVOR TRANSITIONS; CB-VERTICAL-BAR; QUANTUM CHROMODYNAMICS; B-MESON; DECAYS; QCD; QUARKS; DISTRIBUTIONS; RESUMMATION AB I review the existing theoretical uncertainties in relating the semileptonic decay width in b --> u transitions to the underlying Kobayashi-Maskawa mixing element \V-ub\. The theoretical error bars are only a few per cent in \V-ub\, with uncertainties from the impact of the nonperturbative effects nearly negligible. C1 Jefferson Lab, Newport News, VA 23606 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Petersburg Nucl Phys Inst, St Petersburg 188350, Russia. RP Uraltsev, N (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 34 TC 53 Z9 53 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD NOV 20 PY 1999 VL 14 IS 29 BP 4641 EP 4652 DI 10.1142/S0217751X99002177 PG 12 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 256NH UT WOS:000083731100005 ER PT J AU Halpern, MB Schwartz, C AF Halpern, MB Schwartz, C TI Infinite-dimensional free algebra and the forms of the master field SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article AB We find an infinite-dimensional free algebra which lives at large N in any SU(N)invariant action or Hamiltonian theory of bosonic matrices. The natural basis of this algebra is a free-algebraic generalization of Chebyshev polynomials and the dual basis is closely related to the planar connected parts. This leads to a number of free-algebraic forms of the master field including an algebraic derivation of the Gopakumar-Gross form. For action theories, these forms of the master field immediately give a number of new free-algebraic packagings of the planar Schwinger-Dyson equations. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, ERnest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Halpern, MB (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 14 TC 8 Z9 8 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD NOV 20 PY 1999 VL 14 IS 29 BP 4653 EP 4685 DI 10.1142/S0217751X99002189 PG 33 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 256NH UT WOS:000083731100006 ER PT J AU Vu, HX Bezzerides, B DuBois, DF AF Vu, HX Bezzerides, B DuBois, DF TI ASPEN: A fully kinetic, reduced-description particle-in-cell model for simulating parametric instabilities SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE massively parallel; fully kinetic; reduced-description; two dimensional; particle-in-cell; parametric instabilities; stimulated Brillouin scattering; stimulated Raman scattering; Langmuir decay instability ID ELECTROMAGNETIC PLASMA SIMULATION; STIMULATED SCATTERING PROCESSES; LASER-IRRADIATED PLASMAS; RAMAN-SCATTERING; CODE; IMPLICIT; SATURATION; FREQUENCY; BRILLOUIN AB A fully kinetic, reduced-description particle-in-cell (RPIC) model is presented in which deviations from quasineutrality, electron and ion kinetic effects, and nonlinear interactions between low-frequency and high-frequency parametric instabilities are modeled correctly The model is based on a reduced description where the electromagnetic field is represented by three separate temporal envelopes in order to model parametric instabilities with low-frequency and high-frequency daughter waves. Because temporal envelope approximations are invoked, the simulation can be performed an the electron time scale instead of the time scale of the light waves. The electrons and ions are represented by discrete finite-size particles, permitting electron and ion kinetic effects to be modeled properly. The Poisson equation is utilized to ensure that space-charge effects are included. The RPIC model is fully three dimensional and has been implemented in two dimensions on the Accelerated Strategic Computing Initiative (ASCI) parallel computer at Los Alamos National Laboratory and the resulting simulation code has been named ASPEN. We believe this code is the first particle-in-cell code capable of simulating the interaction between low-frequency and high-frequency parametric instabilites in multiple dimensions. Test simulations of stimulated Raman scattering, stimulated Brillouin scattering, and Langmuir decay instability are presented. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. RP Vu, HX (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Div, Los Alamos, NM 87545 USA. NR 37 TC 27 Z9 27 U1 0 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD NOV 20 PY 1999 VL 156 IS 1 BP 12 EP 42 DI 10.1006/jcph.1999.6350 PG 31 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 258NA UT WOS:000083844200002 ER PT J AU Korhonen, P Kulmala, M Laaksonen, A Viisanen, Y McGraw, R Seinfeld, JH AF Korhonen, P Kulmala, M Laaksonen, A Viisanen, Y McGraw, R Seinfeld, JH TI Ternary nucleation of H2SO4, NH3, and H2O in the atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; CLOUD CONDENSATION NUCLEI; METHANE SULFONIC-ACID; SULFURIC-ACID; PARTICLE NUCLEATION; THERMODYNAMIC MODEL; GROWTH; RATES; WATER; EQUILIBRIUM AB Classical theory of binary homogeneous nucleation is extended to the ternary system H2SO4-NH3-H2O For NH3 mixing ratios exceeding about 1 ppt, the presence of NH3 enhances the binary H2SO4-H2O nucleation rate by several orders of magnitude. The Gibbs free energies of formation of the critical H2SO4-NH3-H2O cluster, as calculated by two independent approaches, are in substantial agreement. The finding that the H2SO4-NH3-H2O ternary nucleation rate is independent of relative humidity over a large range of H2SO4 concentrations has wide atmospheric consequences. The limiting component for ternary H2SO4-NH3-H2O nucleation is, as in the binary H2SO4-H2O case, H2SO4; however, the H2SO4 concentration needed to achieve significant nucleation rates is several orders of magnitude below that required in the binary case. C1 CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. Univ Kuopio, Dept Appl Phys, FIN-70211 Kuopio, Finland. Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. Univ Helsinki, Dept Phys, Helsinki 00014, Finland. CALTECH, Dept Chem Engn, Pasadena, CA 91125 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. RP Seinfeld, JH (reprint author), CALTECH, Div Engn & Appl Sci, Mail Code 104-44, Pasadena, CA 91125 USA. EM seinfeld@its.caltech.edu RI Laaksonen, Ari/B-5094-2011; Kulmala, Markku/I-7671-2016 OI Laaksonen, Ari/0000-0002-1657-2383; Kulmala, Markku/0000-0003-3464-7825 NR 43 TC 230 Z9 235 U1 9 U2 45 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV 20 PY 1999 VL 104 IS D21 BP 26349 EP 26353 DI 10.1029/1999JD900784 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 257KN UT WOS:000083781200018 ER PT J AU Michelsen, HA Webster, CR Manney, GL Scott, DC Margitan, JJ May, RD Irion, FW Gunson, MR Russell, JM Spivakovsky, CM AF Michelsen, HA Webster, CR Manney, GL Scott, DC Margitan, JJ May, RD Irion, FW Gunson, MR Russell, JM Spivakovsky, CM TI Maintenance of high HCl/Cl-y and NOx/NOy in the Antarctic vortex: A chemical signature of confinement during spring SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC POLAR VORTEX; HALOGEN OCCULTATION EXPERIMENT; ARCTIC STRATOSPHERE; HYDROGEN-CHLORIDE; SULFURIC-ACID; OZONE LOSS; ATMOS/ATLAS-3 MEASUREMENTS; POTENTIAL VORTICITY; WINTER STRATOSPHERE; INSTRUMENTS ABOARD AB Observations made in the 1994 Antarctic vortex show that Cl-y recovered completely into HCl following conversion of Cl-y reservoir species to active radicals, and NOx constituted a 4-5 times higher fraction of NOy inside the vortex than outside. Measurements made in October and November from the Airborne Southern Hemisphere Ozone Expedition/Measurements of the Atmospheric Effects of Stratospheric Aircraft (ASHOE/MAESA) ER-2 aircraft mission, the third Atmospheric Laboratory for Applications and Science (ATLAS-3) space shuttle mission, and the Upper Atmosphere Research Satellite (UARS) demonstrate that this unusual partitioning of Cl-y and NOy was maintained for at least 4 weeks in the springtime vortex. In response to severe ozone loss, abundances of HCl and NOx remained high despite temperatures low enough to reactivate Cl-y and convert NOx to HNO3 via heterogeneous processes. Thus, under severely ozone depleted conditions, high HCl and NOx abundances in the vortex are maintained until the vortex breaks up or an influx of ozone-rich extravortex air is entrained into the vortex. These observations suggest that the flux of extravortex air entering the core of the lower stratospheric vortex was small or negligible above similar to 400 K during late spring, despite weakening of the vortex during this time period. Results of a photochemical model constrained by the measurements suggest that extravortex air entrained into the vortex during October and early November made up less than 5% of the vortex core air at 409 K. The model results also show that heterogeneous chemistry has little effect on the Cl-y and NOy partitioning once high abundances of HCl have been attained under ozone depleted conditions, even when aerosol loading is high. C1 Sandia Natl Labs, Livermore, CA 94551 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Atmospher & Environm Res Inc, San Ramon, CA USA. RP Michelsen, HA (reprint author), Sandia Natl Labs, MS 9055,POB 969, Livermore, CA 94551 USA. EM hamiche@ca.sandia.gov; chris.r.webster@jpl.nasa.gov; manney@mls.jpl.nasa.gov; dcscott@alpha1.jpl.nasa.gov; jjm@mark4sun.jpl.nasa.gov; rmay@alpha1.jpl.nasa.gov; fwi@caesar.jpl.nasa.gov; mrg@caesar.jpl.nasa.gov; jmr@lcas.hamptonu.edu; cms@io.harvard.edu NR 100 TC 28 Z9 28 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV 20 PY 1999 VL 104 IS D21 BP 26419 EP 26436 DI 10.1029/1999JD900473 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 257KN UT WOS:000083781200023 ER PT J AU Ramratnam, B Bonhoeffer, S Binley, J Hurley, A Zhang, LQ Mittler, JE Markowitz, M Moore, JP Perelson, AS Ho, DD AF Ramratnam, B Bonhoeffer, S Binley, J Hurley, A Zhang, LQ Mittler, JE Markowitz, M Moore, JP Perelson, AS Ho, DD TI Rapid production and clearance of HIV-1 and hepatitis C virus assessed by large volume plasma apheresis SO LANCET LA English DT Article ID DYNAMICS IN-VIVO; ACQUIRED IMMUNODEFICIENCY SYNDROME; INTERFERON-ALPHA; MONKEY MODEL; TURNOVER; INFECTION; THERAPY; TYPE-1; SYSTEM AB Background In chronic HIV-1 infection, dynamic equilibrium exists between viral production and clearance. The half-life of free virions can be estimated by inhibiting virion production with antiretroviral agents and modelling the resulting decline in plasma HIV-1 RNA. To define HIV-1 and hepatitis C virus (HCV) dynamics, we used plasma apheresis to increase virion clearance temporarily while leaving Virion production unaffected. Methods Plasma virus loads were measured frequently before, during, and after apheresis in four HIV-1-infected patients, two of whom were also co-infected with HCV. Rates of virion clearance were derived by non-linear least-square fitting of plasma virus load to a model of Viral dynamics. Findings Virion clearance rate constants were 0.0063/min (9.1/day) to 0.025/min (36.0/day; half-life 28-110 min) for HIV-1 and 0.0038/min (5.5/day) to 0.0069/min (9.9/day; half-life 100-182 min) for HCV. These values provided estimates of daily particle production of 9.3 log(10)-10.2 log(10) particles for HIV-1 and 11.6 log(10)-13.0 log(10) particles for HCV. Interpretation Our findings confirm that HIV-1 and HCV are produced and cleared extremely rapidly. New estimates for HIV-1 clearance are up to ten times higher than previous ones, whereas HCV clearance is similar to previous estimates. C1 Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. ETH Zentrum NW, Zurich, Switzerland. Friedrich Miescher Inst, CH-4002 Basel, Switzerland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Ho, DD (reprint author), Rockefeller Univ, Aaron Diamond AIDS Res Ctr, 455 1st Ave, New York, NY 10016 USA. RI Bonhoeffer, Sebastian/A-2735-2008 OI Bonhoeffer, Sebastian/0000-0001-8052-3925 FU NCRR NIH HHS [MO1-RR00102]; NIAID NIH HHS [AI40387, AI41534] NR 20 TC 281 Z9 283 U1 1 U2 3 PU LANCET LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0140-6736 J9 LANCET JI Lancet PD NOV 20 PY 1999 VL 354 IS 9192 BP 1782 EP 1785 DI 10.1016/S0140-6736(99)02035-8 PG 4 WC Medicine, General & Internal SC General & Internal Medicine GA 258RM UT WOS:000083853000013 PM 10577640 ER PT J AU Yan, YF Chisholm, MF Pennycook, SJ Pantelides, ST AF Yan, YF Chisholm, MF Pennycook, SJ Pantelides, ST TI Structures of pure and Ca-segregated MgO (001) surfaces SO SURFACE SCIENCE LA English DT Article DE ab initio calculations; magnesium oxide; segregation; surface ID MGO(001) SURFACE; AG/MGO(001); RELAXATION; ENERGETICS; MODEL AB The structures of pure and Ca-segregated MgO (001) surfaces have been studied using first-principles density-functional theory. The relaxation and rumpling for the pure surface are found to be 0.48% and 1.62%, respectively. Ca segregation significantly modifies the surface structure. The surface-segregated Ca atoms protrude outwards owing to the size mismatch between Ca and Mg. Consequently, their nearest neighbor oxygen atoms are pulled up. The value of the protrusion of Ca atoms is strongly dependent on the Ca coverage of the surface. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Yan, YF (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 18 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD NOV 20 PY 1999 VL 442 IS 2 BP 251 EP 255 DI 10.1016/S0039-6028(99)00923-1 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 258LE UT WOS:000083840000017 ER PT J AU Szoke, A AF Szoke, A TI Time-resolved holographic diffraction at atomic resolution SO CHEMICAL PHYSICS LETTERS LA English DT Article ID X-RAY CRYSTALLOGRAPHY; PROTEIN PHOTOCYCLE INTERMEDIATE; ELECTRON-DIFFRACTION; MICROSCOPY; IMAGES AB This article proposes a new way to obtain the diffraction patterns of well oriented molecules at atomic resolution. The method bridges internal source holography, X-ray crystallography and gas phase electron diffraction. It can accurately recover the scatterer in three spatial dimensions. Using pump-probe techniques, it is capable of simultaneous femtosecond time resolution and Angstrom spatial resolution in three dimensions. It can be implemented using existing sources of short pulses of monochromatic electrons or X-rays. It is applicable to the measurement of surface and bulk chemical reactions. The possibility of elucidating enzymatic reactions in macromolecules is of particular interest. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Szoke, A (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-30, Livermore, CA 94551 USA. NR 35 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD NOV 19 PY 1999 VL 313 IS 5-6 BP 777 EP 788 DI 10.1016/S0009-2614(99)00915-X PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 261AJ UT WOS:000083985400009 ER PT J AU Matsumoto, Y Kim, K Hurwitz, J Gary, R Levin, DS Tomkinson, AE Park, MS AF Matsumoto, Y Kim, K Hurwitz, J Gary, R Levin, DS Tomkinson, AE Park, MS TI Reconstitution of proliferating cell nuclear antigen-dependent repair of apurinic/apyrimidinic sites with purified human proteins SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID BASE-EXCISION-REPAIR; DNA-POLYMERASE-DELTA; AUXILIARY PROTEIN; TERMINAL REGION; PCNA BINDING; REQUIREMENT; INVOLVEMENT; EPSILON; BETA; IDENTIFICATION AB An apurinic/apyrimidinic (AP) site is one of the most abundant lesions spontaneously generated in living cells and is also a reaction intermediate in base excision repair. In higher eukaryotes, there are two alternative pathways for base excision repair: a DNA polymerase P-dependent pathway and a proliferating cell nuclear antigen (PCNA)-dependent pathway. Here we have reconstituted PCNA-dependent repair of AP sites with six purified human proteins: AP endonuclease, replication factor C, PCNA, flap endonuclease 1 (FEN1), DNA polymerase delta, and DNA ligase I. The length of nucleotides replaced during the repair reaction (patch size) was predominantly two nucleotides, although longer patches of up to seven nucleotides could be detected. Neither replication protein A nor Ku70/80 enhanced the repair activity in this system. Disruption of the PCNA-binding site of either FEN1 or DNA ligase I significantly reduced efficiency of AP site repair but did not affect repair patch size. C1 Fox Chase Canc Ctr, Dept Radiat Oncol, Philadelphia, PA 19111 USA. Mem Sloan Kettering Canc Ctr, Program Mol Biol, New York, NY 10021 USA. Univ Calif Los Alamos Natl Lab, Life Sci Div M888, Los Alamos, NM 87545 USA. Univ Texas, Hlth Sci Ctr, Dept Mol Med, San Antonio, TX 78245 USA. RP Matsumoto, Y (reprint author), Fox Chase Canc Ctr, Dept Radiat Oncol, 7701 Burholme Ave, Philadelphia, PA 19111 USA. RI Gary, Ronald/A-8650-2008 OI Gary, Ronald/0000-0001-5079-1953 FU NCI NIH HHS [CA06927, CA63154, CA71630] NR 42 TC 138 Z9 145 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 NOV 19 PY 1999 VL 274 IS 47 BP 33703 EP 33708 DI 10.1074/jbc.274.47.33703 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 256UQ UT WOS:000083745200077 PM 10559261 ER PT J AU Sohlberg, K Sumpter, BG Noid, DW AF Sohlberg, K Sumpter, BG Noid, DW TI Semi-empirical study of a prototype rotaxane-based molecular shuttle SO JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM LA English DT Article DE semi-empirical calculations; rotaxane; molecular shuttle ID STABILITY AB We report the results of AMI semi-empirical electronic structure calculations on a prototype photochemically driven molecular shuttle based on a rotaxane. As inferred experimentally, the ring component of the rotaxane is shown to favor a different position about the shaft component depending on whether the shaft is in the trans or cis conformation. The calculations show that the shuttling action of the cyclodextrin ring is accompanied by the (de)formation of a kink in the shaft. Published by Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Sohlberg, K (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, 4500N MS6197, Oak Ridge, TN 37831 USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 14 TC 17 Z9 17 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 J MOL STRUC-THEOCHEM JI Theochem-J. Mol. Struct. PD NOV 19 PY 1999 VL 491 BP 281 EP 286 DI 10.1016/S0166-1280(99)00190-6 PG 6 WC Chemistry, Physical SC Chemistry GA 253EQ UT WOS:000083544000029 ER PT J AU Horita, J Driesner, T Cole, DR AF Horita, J Driesner, T Cole, DR TI Pressure effect on hydrogen isotope fractionation between brucite and water at elevated temperatures SO SCIENCE LA English DT Article ID OXYGEN; 500-DEGREES-C; EXCHANGE; MINERALS; SYSTEM; QUARTZ; 100-DEGREES-C; SPECTROSCOPY; TOURMALINE; ANORTHITE AB Experimental evidence for a pressure effect on isotopic partitioning at elevated temperatures demonstrates that equilibrium deuterium-protium fractionation between the mineral brucite [Mg(OH)(2)] and pure water systematically increases by 12.4 per mil as pressure increases from 15 to 800 megapascals at 380 degrees C, A linear relation is observed between the measured fractionation factor and the density of water (0.070 to 1.035 grams per cubic centimeter). The trend of the isotope pressure effect is the same as that of recent theoretical studies, but the magnitude is smaller. The pressure effect must be accounted for in the interpretation of isotopic data of geologic systems involving water (paleotemperature, source of fluids). C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Horita, J (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB MS 6110, Oak Ridge, TN 37831 USA. RI Driesner, Thomas/N-6361-2016 NR 39 TC 27 Z9 31 U1 2 U2 10 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD NOV 19 PY 1999 VL 286 IS 5444 BP 1545 EP 1547 DI 10.1126/science.286.5444.1545 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 257DZ UT WOS:000083768300053 ER PT J AU Bewley, MC Springer, K Zhang, YB Freimuth, P Flanagan, JM AF Bewley, MC Springer, K Zhang, YB Freimuth, P Flanagan, JM TI Structural analysis of the mechanism of adenovirus binding to its human cellular receptor, CAR SO SCIENCE LA English DT Article ID GP120 ENVELOPE GLYCOPROTEIN; TYPE-5 FIBER PROTEIN; CRYSTAL-STRUCTURE; DOMAIN; HIV; RESOLUTION; CD4 AB Binding of virus particles to specific host cell surface receptors is known to be an obligatory step in infection even though the molecular basis for these interactions is not well characterized. The crystal structure of the adenovirus fiber knob domain in complex with domain I of its human cellular receptor, coxsackie and adenovirus receptor (CAR), is presented here. Surface-exposed Loops on knob contact one face of CAR, forming a high-affinity complex. Topology mismatches between interacting surfaces create interfacial solvent-filled cavities and channels that may be targets for antiviral drug therapy. The structure identifies key determinants of binding specificity, which may suggest ways to modify the tropism of adenovirus-based gene therapy vectors. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Flanagan, JM (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. FU NCRR NIH HHS [1P41 RR12408-01A1] NR 23 TC 309 Z9 314 U1 1 U2 14 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 NOV 19 PY 1999 VL 286 IS 5444 BP 1579 EP 1583 DI 10.1126/science.286.5444.1579 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 257DZ UT WOS:000083768300064 PM 10567268 ER PT J AU Manaa, MR Fried, LE AF Manaa, MR Fried, LE TI Intersystem crossings in model energetic materials SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID EXCITED-STATES; NITRIC-ACID; LIQUID NITROMETHANE; AB-INITIO; GRADIENT; DECOMPOSITION; EXCITATION; GEOMETRIES; MOLECULES; SURFACES AB We consider the role of the lowest singlet-tripler intersystem crossing in molecular nitromethane, nitramine, and nitric acid using ab initio complete active space self-consistent field (CAS SCF) wave functions. These systems represent the simplest models of C-(NO2), N-(NO2), and O-(NO2) bonds in energetic materials. The lowest triplet state of these molecules exhibits a minimum equilibrium structure where the nitro group is no longer coplanar with the X (C, N, O) atom, in contrast to the equilibrium geometry of the ground-state singlets. CAS SCF and density functional theory (DFT) fully optimized triplet potential energy curves confirm that the triplets are adiabatically bound with respect to X-(NO2) bond dissociation pathway, with energy barriers at the CAS SCF level of 33, 25, and 15 kcal/mol, respectively. DFT optimizations produced barriers 9-15 kcal/mol lower than the CAS SCF. Singlet-triplet minimum energy crossing points have been located at 13, 8, and 4 kcal/mol above the respective triplet minima. The reported calculations should predict fast nonradiative transitions due to the crossings with the ground surfaces. This prediction is discussed in connection with the energetic properties of these systems. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94551 USA. RP Manaa, MR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, POB 808,L-282, Livermore, CA 94551 USA. RI Fried, Laurence/L-8714-2014 OI Fried, Laurence/0000-0002-9437-7700 NR 45 TC 35 Z9 35 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD NOV 18 PY 1999 VL 103 IS 46 BP 9349 EP 9354 DI 10.1021/jp992460o PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 260XL UT WOS:000083978700026 ER PT J AU Wang, R Parikh, AN Beers, JD Shreve, AP Swanson, B AF Wang, R Parikh, AN Beers, JD Shreve, AP Swanson, B TI Nonequilibrium pattern formation in Langmuir-phase assisted assembly of alkylsiloxane monolayers SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ATOMIC-FORCE MICROSCOPY; X-RAY REFLECTIVITY; SURFACES; FILMS; INSTABILITIES; ELLIPSOMETRY; ADSORPTION; SHAPES; WATER; LIGHT AB Prepolymerized n-octadecyltrichlorosilane (OTS) monolayers were deposited onto oxidized silicon substrates from precursor Langmuir monolayers (at an air-water interface) in two-dimensional liquid expanded (LE), Liquid condensed (LC), or mixed (LE/LC coexistence phase) states at four different pulling rates. Morphologies of the transferred monolayers have been investigated: using atomic force microscopy (AFM). The OTS monolayers formed from the LE phase precursor reveal an incipient condensation transition exhibiting a novel ring-in-a-ring morphology, wherein uniformly distributed circular domains consisting of two concentric walls of ordered OTS molecules in a high density phase both sandwich and encapsulate disordered OTS molecules in a reduced density phase. On the other hand, the monolayers formed from the LC/LE phase precursor implicate a complete condensation transition, evidenced in the AFM images showing a uniform tiling of near-circular domains composed of ordered OTS molecules in a dense monolayer phase. The monolayers derived from the 2D solid or LC precursor state reveal near-complete surface coverages and uniform film structures, comparable to those obtained by adsorption from a dilute organic solution of OTS molecules (conventional self-assembly process). These structural reconstructions at the substrate surface, namely lateral redistribution into 2D domains, condensation transitions and film coverages, are discussed in terms of the competition between short range and long range interactions. The most dominant effect of increasing pulling rates is the appearance of coalesced domain structures, presumably due to drainage of the water layer at the substrate surface as well as occasional substrate pinning. These results substantiate the idea that templating surface self-assembly of monolayers by using their Langmuir-phase precursors provides a useful alternative to classical solution-phase self-assembly approaches, and affords a wide range of control over film structures and surface morphologies. C1 Univ Calif Los Alamos Natl Lab, Div Biosci, Los Alamos, NM 87545 USA. RP Wang, R (reprint author), Univ Calif Los Alamos Natl Lab, Div Biosci, POB 1663, Los Alamos, NM 87545 USA. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 NR 31 TC 18 Z9 18 U1 0 U2 1 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 NOV 18 PY 1999 VL 103 IS 46 BP 10149 EP 10157 DI 10.1021/jp992030y PG 9 WC Chemistry, Physical SC Chemistry GA 260XJ UT WOS:000083978500013 ER PT J AU Schatz, T Cook, AR Meisel, D AF Schatz, T Cook, AR Meisel, D TI Capture of charge carriers at the silica nanoparticle-water interface SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ELECTRON-TRANSFER PROCESSES; METHYL VIOLOGEN; PULSE-RADIOLYSIS; RADIATION-CHEMISTRY; AQUEOUS-SOLUTION; SIO2; PHOTOCHEMISTRY; RADICALS; COLLOIDS; YIELDS AB Aqueous suspensions of methyl viologen, MV2+, adsorbed onto silica nanoparticles were irradiated using pulse radiolysis, and the yield of the radical cation was determined. It is shown that the yield of MV+ increases upon increasing the weight percent of SiO2 in the sample. This increase parallels the increase in the yield of hydrated electrons that was previously observed to result from an increase in the absorbed dose by the silica particles. The increase in adsorbate abundance at the surface changes the surface-charge density, but it is shown that the increase in the yield is not merely due to changes in the surface potential; an acceptor state at the surface is required. However, the possibility that the presence of an acceptor at the interface affects charge separation within the particle cannot be dismissed. C1 Univ Notre Dame, Radiat Lab, Notre Dame, IN 46556 USA. Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Meisel, D (reprint author), Univ Notre Dame, Radiat Lab, Notre Dame, IN 46556 USA. OI Cook, Andrew/0000-0001-6633-3447 NR 24 TC 22 Z9 22 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 18 PY 1999 VL 103 IS 46 BP 10209 EP 10213 DI 10.1021/jp992269e PG 5 WC Chemistry, Physical SC Chemistry GA 260XJ UT WOS:000083978500020 ER PT J AU Fukuda, Y Ishihara, K Itow, Y Kajita, T Kameda, J Kasuga, S Kobayashi, K Kobayashi, Y Koshio, Y Miura, M Nakahata, M Nakayama, S Obayashi, Y Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, H Takeuchi, Y Totsuka, Y Yamada, S Earl, M Habig, A Kearns, E Messier, MD Scholberg, K Stone, JL Sulak, LR Walter, CW Goldhaber, M Barszczak, T Casper, D Gajewski, W Kropp, WR Mine, S Price, LR Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Kibayashi, A Learned, JG Matsuno, S Stenger, VJ Takemori, D Ishii, T Ishino, H Kobayashi, T Nakamura, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT Inagaki, T Nishikawa, K Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Goodman, JA Sullivan, GW Hill, J Jung, CK Martens, K Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Doki, W Kirisawa, M Inaba, S Miyano, K Okazawa, H Saji, C Takahashi, M Takahata, M Higuchi, K Nagashima, Y Takita, M Yamaguchi, T Yoshida, M Kim, SB Etoh, M Hasegawa, A Hasegawa, T Hatakeyama, S Inoue, K Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Hatakeyama, Y Koike, M Nemoto, M Nishijima, K Fujiyasu, H Futagami, T Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D George, JS Stachyra, AL Wilkes, RJ Young, KK AF Fukuda, Y Ishihara, K Itow, Y Kajita, T Kameda, J Kasuga, S Kobayashi, K Kobayashi, Y Koshio, Y Miura, M Nakahata, M Nakayama, S Obayashi, Y Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, H Takeuchi, Y Totsuka, Y Yamada, S Earl, M Habig, A Kearns, E Messier, MD Scholberg, K Stone, JL Sulak, LR Walter, CW Goldhaber, M Barszczak, T Casper, D Gajewski, W Kropp, WR Mine, S Price, LR Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Kibayashi, A Learned, JG Matsuno, S Stenger, VJ Takemori, D Ishii, T Ishino, H Kobayashi, T Nakamura, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT Inagaki, T Nishikawa, K Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Goodman, JA Sullivan, GW Hill, J Jung, CK Martens, K Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Doki, W Kirisawa, M Inaba, S Miyano, K Okazawa, H Saji, C Takahashi, M Takahata, M Higuchi, K Nagashima, Y Takita, M Yamaguchi, T Yoshida, M Kim, SB Etoh, M Hasegawa, A Hasegawa, T Hatakeyama, S Inoue, K Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Hatakeyama, Y Koike, M Nemoto, M Nishijima, K Fujiyasu, H Futagami, T Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D George, JS Stachyra, AL Wilkes, RJ Young, KK CA Super Kamiokande Collaboration TI Neutrino-induced upward stopping muons in Super-Kamiokande SO PHYSICS LETTERS B LA English DT Article DE neutrino oscillations; Super-Kamiokande; upward stopping muons; upward throughgoing muons; atmospheric muon neutrinos; cosmic rays ID CTEQ PARTON DISTRIBUTIONS; ATMOSPHERIC NEUTRINOS; FLUX; OSCILLATIONS AB A total of 137 upward stopping muons of minimum energy 1.6 GeV are observed by Super-Kamiokande during 516 detector live days. The measured muon flux is 0.39 +/- 0.04(stat.) +/- 0.02(syst.) X 10(-13) cm(-2)s(-1)sr(-1) compared to an expected flux of 0.73 +/- 0.16(theo.)X 10(-13) cm(-2)s(-1)sr(-1). Using our previously-published measurement of the upward through-going muon flux, we calculate the stopping/through-going flux ratio R, which has less theoretical uncertainty. The measured value of R = 0.22 +/- 0.02(stat.) +/- 0.01(syst.) is significantly smaller than the value 0.37(-0.04)(+0.05)(theo.) expected using the best theoretical information (the probability that the measured R is a statistical fluctuation below the expected value is 0.39%). A simultaneous fitting to zenith angle distributions of upward stopping and through-going muons gives a result which is consistent with the hypothesis of neutrino oscillations with the parameters sin(2)2 theta > 0.7 and 1.5 X 10(-3) < Delta m(2) < 1.5 X 10(-2) eV(2) at 90% confidence level, providing a confirmation of the observation of neutrino oscillations by Super-Kamiokande using the contained atmospheric neutrino events. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan. Boston Univ, Dept Phys, Boston, MA 02215 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. Calif State Univ Dominguez Hills, Dept Phys, Carson, CA 90747 USA. George Mason Univ, Dept Phys, Fairfax, VA 22030 USA. Gifu Univ, Dept Phys, Gifu 5011193, Japan. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. KEK, High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 3050801, Japan. Kobe Univ, Dept Phys, Kobe, Hyogo 6578501, Japan. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87544 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Niigata Univ, Dept Phys, Niigata 9502181, Japan. Osaka Univ, Dept Phys, Toyonaka, Osaka 5600043, Japan. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tokyo, Tokyo 1130033, Japan. Tokai Univ, Dept Phys, Hiratsuka, Kanagawa 1521292, Japan. Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Fukuda, Y (reprint author), Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan. RI Obayashi, Yoshihisa/A-4472-2011; Takeuchi, Yasuo/A-4310-2011; Nakamura, Kenzo/F-7174-2010; Sobel, Henry/A-4369-2011; Suzuki, Yoichiro/F-7542-2010; Martens, Kai/A-4323-2011; Wilkes, R.Jeffrey/E-6011-2013; Kim, Soo-Bong/B-7061-2014; Sakurai, Nobuyuki/M-5009-2014; Ishino, Hirokazu/C-1994-2015; Koshio, Yusuke/C-2847-2015; Kibayashi, Atsuko/K-7327-2015 OI Sakurai, Nobuyuki/0000-0002-1002-217X; Ishino, Hirokazu/0000-0002-8623-4080; Koshio, Yusuke/0000-0003-0437-8505; NR 21 TC 214 Z9 214 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 18 PY 1999 VL 467 IS 3-4 BP 185 EP 193 DI 10.1016/S0370-2693(99)01188-0 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259TW UT WOS:000083910900001 ER PT J AU Matchev, KT Pierce, DM AF Matchev, KT Pierce, DM TI New backgrounds in trilepton, dilepton and dilepton plus tau jet SUSY signals at the tevatron SO PHYSICS LETTERS B LA English DT Article DE supersymmetry; tevatron; trileptons; dileptons ID CHARGINO-NEUTRALINO PRODUCTION; FERMILAB-TEVATRON; P(P)OVER-BAR COLLISIONS; SUPERSYMMETRY REACH; PBARP COLLIDERS; ROOT-S=1.8 TEV; SUPERGRAVITY; SEARCH; PYTHIA-5.7; GENERATION AB We determine the Tevatron's reach in supersymmetric parameter space in trilepton, Like-sign dilepton, and dilepton plus tau-jet channels, taking all relevant backgrounds into account. We show results for the minimal supergravity model. With a standard set of cuts we find that the previously unaccounted for W gamma* background is larger than all other backgrounds combined. We include cuts on the dilepton invariant mass and the W-boson transverse mass to reduce the W gamma* background to a reasonable level. We optimize cuts at each point in supersymmetry parameter space in order to maximize signal-to-noise. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Matchev, KT (reprint author), Fermi Natl Accelerator Lab, Dept Theoret Phys, POB 500, Batavia, IL 60510 USA. NR 47 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 NOV 18 PY 1999 VL 467 IS 3-4 BP 225 EP 231 DI 10.1016/S0370-2693(99)01155-7 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259TW UT WOS:000083910900007 ER PT J AU Burakovsky, L Page, PR Goldman, T AF Burakovsky, L Page, PR Goldman, T TI Generalized Schwinger mass formula SO PHYSICS LETTERS B LA English DT Article DE Schwinger's formula; mass matrix; isosinglet-mesons mixing ID SPECTROSCOPY AB We generalize Schwinger's original mass formula to the case of an additional isosinglet mixing with the nonet mesons. We then make further generalization to either (i) an arbitrary number of additional isosinglets mixing with nonet mesons, or (ii) an arbitrary number of mesons mixing with an additional isosinglet. In the former case, we present an explicit relation, while in the latter case, we show by numerical example that the new mass formula is only weakly affected by the inclusion of additional mesons, and hence holds with good accuracy for each of the 3 X 3 mass sub-matrices. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Burakovsky, L (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B283, Los Alamos, NM 87545 USA. RI Page, Philip/L-1885-2015 OI Page, Philip/0000-0002-2201-6703 NR 19 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 18 PY 1999 VL 467 IS 3-4 BP 255 EP 262 DI 10.1016/S0370-2693(99)01163-6 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259TW UT WOS:000083910900011 ER PT J AU Buchko, GW Daughdrill, GW de Lorimier, R Rao, S Isern, NG Lingbeck, JM Taylor, JS Wold, MS Gochin, M Spicer, LD Lowry, DF Kennedy, MA AF Buchko, GW Daughdrill, GW de Lorimier, R Rao, S Isern, NG Lingbeck, JM Taylor, JS Wold, MS Gochin, M Spicer, LD Lowry, DF Kennedy, MA TI Interactions of human nucleotide excision repair protein XPA with DNA and RPA70 Delta C327: Chemical shift mapping and N-15 NMR relaxation studies SO BIOCHEMISTRY LA English DT Article ID MAGNETIC-RESONANCE RELAXATION; MODEL-FREE APPROACH; XERODERMA-PIGMENTOSUM; BACKBONE DYNAMICS; BINDING DOMAIN; DAMAGED DNA; TRANSCRIPTION FACTOR; MAMMALIAN-CELLS; FACTOR TFIIH; SH2 DOMAIN AB Human XPA is an essential component in the multienzyme nucleotide excision repair (NER) pathway. The solution structure of the minimal DNA binding domain of XPA (XPA-MBD: M98-F219) was recently determined [Buchko et al. (1998) Nucleic Acids Res. 26, 2779-2788, Ikegami et al, (1998) Nat. Struct. Biol. 5, 701-706] and shown to consist of a compact zinc-binding core and a loop-rich C-terminal subdomain connected by a linker sequence. Here, the solution structure of XPA-MBD was further refined using an entirely new class of restraints based on pseudocontact shifts measured in cobalt-substituted XPA-MBD, Using this structure, the surface of XPA-MBD which interacts with DNA and a fragment of the largest subunit of replication protein A (RPA70 Delta C327: M1-Y326) was determined using chemical shift mapping. DNA binding in XPA-MBD was highly localized in the loop-rich subdomain for DNA with or without a lesion [dihydrothymidine (dhT) or 6-4-thymidine-cytidine (64TC)], or with DNA in single- or- double-stranded form, indicating that the character of the lesion itself is not the driving force for XPA binding DNA. RPA70 Delta C327 was found to contact regions in both the zinc-binding and loop-rich subdomains, Some overlap of the DNA and RPA70 Delta C327 binding regions was observed in the loop-rich subdomain, indicating a possible cooperative DNA-binding mode between XPB and RP870 Delta C327. To complement the chemical shift mapping data, the backbone dynamics of free XPA-MBD and XPA-MBD bound to DNA oligomers containing dhT or 64TC lesions were investigated using N-15 NMR relaxation data. The dynamic analyses for the XPA-MBD complexes with DNA revealed localized increases and decreases in S-2 and an increase in the global correlation time. Regions of XPA-MBD with the largest increases in S-2 overlapped regions having the largest chemical shifts changes upon binding DNA, indicating that the loop-rich subdomain becomes more rigid upon binding DNA, Interestingly, S-2 decreased for some residues in the zinc-binding core upon DNA association, indicating a possible concerted structural rearrangement on binding DNA, C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Duke Univ, Med Ctr, Dept Biochem, Durham, NC 27710 USA. Duke Univ, Med Ctr, Dept Radiol, Durham, NC 27710 USA. Univ Iowa, Coll Med, Dept Biochem, Iowa City, IA 52240 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. RP Kennedy, MA (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Wold, Marc/F-5806-2010; Isern, Nancy/J-8016-2013; Buchko, Garry/G-6173-2015 OI Buchko, Garry/0000-0002-3639-1061 FU NIGMS NIH HHS [R29 GM053164-05, R01 GM044721, R29 GM053164] NR 67 TC 55 Z9 58 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 NOV 16 PY 1999 VL 38 IS 46 BP 15116 EP 15128 DI 10.1021/bi991755p PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 259NF UT WOS:000083899400007 PM 10563794 ER PT J AU Segel, DJ Eliezer, D Uversky, V Fink, AL Hodgson, KO Doniach, S AF Segel, DJ Eliezer, D Uversky, V Fink, AL Hodgson, KO Doniach, S TI Transient dimer in the refolding kinetics of cytochrome c characterized by small-angle X-ray scattering SO BIOCHEMISTRY LA English DT Article ID SIZE-EXCLUSION CHROMATOGRAPHY; MICROSECOND TIME-SCALE; STRUCTURAL CHARACTERIZATION; SOLVENT DENATURATION; GLOBULAR-PROTEINS; UNFOLDED STATES; MOLTEN GLOBULE; INTERMEDIATE; DIFFRACTION; EXCHANGE AB The equilibrium unfolding and the kinetic refolding of cytochrome c (Cyt c) in the presence of imidazole were studied with small-angle X-ray scattering (SAXS). The equilibrium unfolding experiments showed the radius of gyration, R-g, of native Cyt c to swell similar to 1 Angstrom with the addition of imidazole. The thermodynamic parameter rn also reflects an expansion of the protein as its lower value demonstrates an increase in solvent-accessible surface area over that of native Cyt c in the absence of imidazole. Refolding was studied in the presence of imidazole as it prevents misligated intermediate states from forming during the refolding process, simplifying the kinetics, and making them easier to resolve. Time-resolved decreases in the forward scattering amplitude, I(0), demonstrated the transient formation of an aggregated intermediate. Final protein and denaturant concentrations were varied in the refolding kinetics, and the singular value decomposition (SVD) method was employed to characterize the associated state, This state was determined to be a dimer, with properties consistent with a molten globule. C1 Stanford Univ, LAM Appl Phys, Dept Chem & Phys, Stanford, CA 94305 USA. Russian Acad Sci, Inst Biol Instrumentat, Pushchino 142292, Moscow Region, Russia. Univ Calif Santa Cruz, Dept Chem & Biochem, Santa Cruz, CA 95064 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Cornell Univ, Weill Med Coll, Dept Biochem, New York, NY 10021 USA. RP Doniach, S (reprint author), Stanford Univ, LAM Appl Phys, Dept Chem & Phys, McCullough Bldg, Stanford, CA 94305 USA. RI Uversky, Vladimir/F-4515-2011 OI Uversky, Vladimir/0000-0002-4037-5857 FU NCRR NIH HHS [RR-01209] NR 46 TC 56 Z9 56 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD NOV 16 PY 1999 VL 38 IS 46 BP 15352 EP 15359 DI 10.1021/bi991337k PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 259NF UT WOS:000083899400034 PM 10563821 ER PT J AU Yim, H Kent, M McNamara, WF Ivkov, R Satija, S Majewski, J AF Yim, H Kent, M McNamara, WF Ivkov, R Satija, S Majewski, J TI Structure within thin epoxy films revealed by solvent swelling: A neutron reflectivity study SO MACROMOLECULES LA English DT Article ID POLY(METHYL METHACRYLATE); POLYMER BLENDS; SPIN-CAST; INTERFACE SEGREGATION; END-GROUPS; SURFACE; POLY(DIMETHYLSILOXANE); NETWORKS; MICROSTRUCTURE; SPECTROSCOPY AB Structure within thin epoxy films is investigated by neutron reflectivity (NR) as a function of resin/cross-linker composition and cure temperature. Variation in the cross-link density normal to the substrate surface is examined by swelling the films with the good solvent d-nitrobenzene (d-NB). The principal observation is a large excess of d-NB near the air surface. This is not a wetting layer, but rather indicates a lower cross-link density in the near-surface region. This effect is due to preferential segregation of the cross-linker to the air surface, driven by the lower surface tension of the cross-linker relative to the epoxide oligomers. The magnitude of the effect is a function of composition and cure temperature. Exclusion of d-NB from the region immediately adjacent to the substrate surface is also observed, possibly indicating a tightly bound layer of epoxy. Regarding swelling in the bulk of the films, the behavior is nonsymmetric with departure from the stoichiometric ratio. The films deficient in curing agent show greater equilibrium swelling and faster swelling kinetics than the films with an excess of curing agent. C1 Sandia Natl Labs, Dept 1832, Albuquerque, NM 87185 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Los Alamos Natl Lab, LANCSE, Los Alamos, NM USA. RP Kent, M (reprint author), Sandia Natl Labs, Dept 1832, POB 5800, Albuquerque, NM 87185 USA. RI Lujan Center, LANL/G-4896-2012; Ivkov, Robert/A-3902-2015 OI Ivkov, Robert/0000-0002-2930-5276 NR 50 TC 34 Z9 34 U1 3 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 16 PY 1999 VL 32 IS 23 BP 7932 EP 7938 DI 10.1021/ma990990c PG 7 WC Polymer Science SC Polymer Science GA 257HB UT WOS:000083775500029 ER PT J AU Stokes, DL Sepaniak, MJ Vo-Dinhl, T AF Stokes, DL Sepaniak, MJ Vo-Dinhl, T TI Demonstration of a separations-based fiberoptic sensor for bioanalysis SO ANALYTICA CHIMICA ACTA LA English DT Article DE remote sensor; fiberoptic; capillary electrophoresis; bioanalysis; laser-induced fluorescence; DNA ID MOLECULARLY-IMPRINTED POLYMERS; DNA RESTRICTION DIGESTS; CAPILLARY ELECTROPHORESIS; GEL-ELECTROPHORESIS; CHEMICAL-ANALYSIS; CHAIN-REACTION; OPTIMIZATION; SYSTEM; CHIPS AB We present a newly-developed separations-based fiberoptic sensor (SBFOS) for biomedical applications. The sensor features a linear 10 cm effective length section of capillary coupled with a single optical fiber for laser-induced fluorescence (LIF) detection of fluorescently-labeled analytes separated by capillary electrophoresis (CE). The single optical fiber, arranged perpendicular to and touching the capillary, transmits both laser excitation to the sensor and analytical signal from the sensor to a PMT-based detection system. The resulting compact, robust design may prove to be an attractive alternative to conventional CE laboratory systems due to the portability and potential for automation and multiplexing. The sensor has been evaluated with size selective separations of phi X-174 HaeIII digest DNA samples. Baseline resolution for fragments differing by 10 base pairs was routinely observed in separations requiring approximately 10 min. This short analysis time, combined with rapid sensor regeneration capability, enabled the temporal analysis of a digestion of phi X-174 phage DNA by HaeIII restriction enzyme. The use of viscous matrices permits sensor operation in any orientation without introducing complications associated with gravity-driven hydrostatic flow. Relative standard deviations in migration rates of the phi X-174 DNA fragments have generally been less than 5%. Furthermore, efficiencies of up to 2.5 million plates/m have been observed, giving the compact sensor a separation quality which is competitive with larger conventional CE systems. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Life Sci, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. RP Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 43 TC 2 Z9 2 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 EI 1873-4324 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD NOV 15 PY 1999 VL 399 IS 3 BP 201 EP 212 DI 10.1016/S0003-2670(99)00463-8 PG 12 WC Chemistry, Analytical SC Chemistry GA 253MH UT WOS:000083560000001 ER PT J AU Stokes, DL Pal, A Narayanan, VA Vo-Dinh, T AF Stokes, DL Pal, A Narayanan, VA Vo-Dinh, T TI Evaluation of a chemical vapor dosimeter using polymer-coated SERS substrates SO ANALYTICA CHIMICA ACTA LA English DT Article DE surface-enhanced Raman scattering; chemical dosimeter; vapor monitor; poly(vinylpyrrolidone); benzoic acid; 2-aminopyrimidine; 2,4-dinitrophenol ID ENHANCED RAMAN-SCATTERING; SILVER ELECTRODE; ELECTROMAGNETIC THEORY; ISLAND FILMS; SPECTROSCOPY; SPECTROMETRY; SURFACES; SPECTRA; PYRIDINE AB This paper describes the development and evaluation of an improved passive chemical dosimeter using poly (vinylpyrrolidone) coating on a surface-enhanced Raman scattering (SERS) substrate for monitoring airborne chemicals. Experimental studies are performed to demonstrate the longevity, enhancement of Raman signals, and selectivity of the dosimeter. The new substrate has been used to monitor exposure to vapors of benzoic acid, 2-aminopyrimidine, and 2,4-dinitrophenol over 20-day periods. The improved performance of the newly developed polymer-coated substrate is compared to that of uncoated SERS substrates. Results of substrate optimization and shelf-life studies are discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Life Sci, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. Indian Inst Technol, Dept Chem, Kharagpur 721302, W Bengal, India. Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Div Life Sci, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. NR 34 TC 17 Z9 18 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD NOV 15 PY 1999 VL 399 IS 3 BP 265 EP 274 DI 10.1016/S0003-2670(99)00462-6 PG 10 WC Chemistry, Analytical SC Chemistry GA 253MH UT WOS:000083560000007 ER PT J AU Zhang, YH Tan, HD Yeung, ES AF Zhang, YH Tan, HD Yeung, ES TI Multiplexed automated DNA sequencing directly from single bacterial colonies SO ANALYTICAL CHEMISTRY LA English DT Article ID CAPILLARY-ARRAY ELECTROPHORESIS; DYE-LABELED TERMINATORS; HUMAN-GENOME-PROJECT; PLASMID DNA; ESCHERICHIA-COLI; PURIFICATION METHOD; PCR AMPLIFICATION; ANALYSIS DEVICE; LARGE-SCALE; HIGH-SPEED AB Sample preparation has been one of the major bottlenecks for large-scale DNA sequencing projects in terms of time and cost. To improve sample throughput and to integrate the front-end tasks to capillary-array DNA sequencers, protocols for directly sequencing the plasmids from a single bacterial colony in fused-silica capillaries were developed. After the colony is picked, lysis is accomplished in situ in the plastic sample tube using either a thermocycler or a heating block. Upon heating, the plasmids are released while chromosomal DNA and membrane proteins are denatured and precipitate to the bottom of the tube. After adding enzyme and Sanger reagents, the resulting solution was aspirated into the reaction capillaries by a syringe pump, and cycle sequencing was initiated. No deleterious effect upon the reaction efficiency, the on-line purification system, or the capillary electrophoresis separation was observed, even though the crude lysate was used as the template. Multiplexed online DNA sequencing data from 8 parallel channels allowed base calling up to 620 bp with an accuracy of 98%. The entire system can be automatically regenerated for repeated operation. By the marriage of colony sequencing with the capillary array sequencer, both the front end and the back end of DNA sequencing are combined in a miniaturized format. This protocol will ultimately reduce the cost of sequencing to well below current levels. C1 Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. NR 59 TC 18 Z9 18 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 1999 VL 71 IS 22 BP 5018 EP 5025 DI 10.1021/ac9904462 PG 8 WC Chemistry, Analytical SC Chemistry GA 255AK UT WOS:000083647100002 PM 10575960 ER PT J AU Bender, F Dahint, R Josse, F Ricco, AJ Martin, SJ AF Bender, F Dahint, R Josse, F Ricco, AJ Martin, SJ TI Characteristics of acoustic plate modes on rotated Y-cuts of quarts utilised for biosensing applications SO ANALYTICAL CHEMISTRY LA English DT Article ID MASS SENSITIVITY; LIQUID SENSORS AB Acoustic plate modes (APM) on various quartz substrates have been investigated in order to determine their usefulness for liquid-sensing applications. The modes have been characterized in terms of their mass sensitivity, mode separation, temperature sensitivity, and reproducibility of the experimental results. Promising characteristics are found for rotated Y-cuts of quartz with the direction of acoustic mode propagation being perpendicular to the X-axis of the quartz crystal. Experiments on the detection of immunochemical reactions are performed using different quartz APM sensors, and the results are compared to similar experiments utilizing APM devices on ZX-LiNbO3. C1 Univ Heidelberg, D-69120 Heidelberg, Germany. Marquette Univ, Dept Elect & Comp Engn, Microsensor Res Lab, Milwaukee, WI 53201 USA. Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. RP Dahint, R (reprint author), Univ Heidelberg, Neuenheimer Feld 253, D-69120 Heidelberg, Germany. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 11 TC 3 Z9 4 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 1999 VL 71 IS 22 BP 5064 EP 5068 DI 10.1021/ac990559l PG 5 WC Chemistry, Analytical SC Chemistry GA 255AK UT WOS:000083647100009 PM 10575962 ER PT J AU Jeong, SH Borisov, OV Yoo, JH Mao, XL Russo, RE AF Jeong, SH Borisov, OV Yoo, JH Mao, XL Russo, RE TI Effects of particle size distribution on inductively coupled plasma mass spectrometry signal intensity during laser ablation of glass samples SO ANALYTICAL CHEMISTRY LA English DT Article ID ATOMIC EMISSION-SPECTROSCOPY; SURFACE; PLUMES AB The relation between laser-generated particles and ICPMS signal intensity was investigated using single-pulse laser ablation sampling of solids. The particle size distribution of glass samples was measured using an optical particle counter for different laser ablation conditions. Ablation of a new surface produced fewer particles and lower ICPMS signal intensity than a preablated surface. Laser power density of 0.4-0.5 GW/cm(2) was found to be a threshold value, across which particle size distribution changed. Laser beam diameter was a more influential parameter than power density in efficient particle generation. Particle loss during transport from the ablation chamber to the ICPMS was significant for a low carrier gas now rate of 0.1 L/min, while almost no loss was observed for a higher now rate of 0.26 L/min, The onset of ICPMS intensity time profiles decreased as more large particles were generated. ICPMS intensity data were calibrated with respect to the particle mass entering the ICPMS. Particle entrainment efficiency of the LA-ICPMS system was estimated and found to be a strong function of laser power density. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 22 TC 76 Z9 77 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 1999 VL 71 IS 22 BP 5123 EP 5130 DI 10.1021/ac990455a PG 8 WC Chemistry, Analytical SC Chemistry GA 255AK UT WOS:000083647100017 ER PT J AU Hadd, AG Jacobson, SC Ramsey, JM AF Hadd, AG Jacobson, SC Ramsey, JM TI Microfluidic assays of acetylcholinesterase inhibitors SO ANALYTICAL CHEMISTRY LA English DT Article ID ORGANO-PHOSPHORUS COMPOUNDS; CAPILLARY ELECTROPHORESIS; PCR AMPLIFICATION; MICROCHIP DEVICE; SAMPLE INJECTION; ENZYME ASSAYS; GLASS CHIP; FLOW; SEPARATIONS; INTEGRATION AB A microfabricated device for flow injection analysis and electrophoretic separation of acetylcholinesterase (AChE) inhibitors is described. Solutions of inhibitor, enzyme, substrate, and derivitizing agent were mixed within the channels of the microchip using computer-controlled electrokinetic transport. AChE-catalyzed hydrolysis of acetylthiocholine to thiocholine was measured in an onchip reaction of thiocholine with coumarinylphenylmaleimide, and the resulting thioether was detected by laser-induced fluorescence. Inhibitors reduced the fluorescence signal and produced a negative peak diagnostic for the type of inhibition. A Gaussian peak was observed for competitive inhibitors, whereas a broad negative peak was observed for irreversible inhibitors. From a microchip assay for tacrine, an inhibition constant, K-i, of 1.5 +/- 0.2 nM was derived, which compared well with a standard cuvette assay, A now injection assay of two irreversible inhibitors, carbofuran and eserine, was performed. With a Ei-min stopped-flow reaction time, a detection limit of 10 nM carbofuran was obtained. As a potential multiplex screening device, a mixture of four cationic inhibitors, tacrine, edrophonium, and tetramethyl- and tetraethylammonium chloride, was separated and detected within 70 s. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 42 TC 171 Z9 174 U1 2 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 1999 VL 71 IS 22 BP 5206 EP 5212 DI 10.1021/ac990591f PG 7 WC Chemistry, Analytical SC Chemistry GA 255AK UT WOS:000083647100028 ER PT J AU Luo, Y Hall, DC Kou, L Steingart, L Jackson, JH Blum, O Hou, H AF Luo, Y Hall, DC Kou, L Steingart, L Jackson, JH Blum, O Hou, H TI Oxidized AlxGa1-xAs heterostructure planar waveguides SO APPLIED PHYSICS LETTERS LA English DT Article ID WAVE-GUIDES; MU-M; OXIDATION; ALGAAS AB Waveguiding by total internal reflection is demonstrated within AlxGa1-xAs semiconductor heterostructures which have been fully oxidized in water vapor at similar to 490 degrees C. Refractive index, mode propagation constant, propagation loss (less than or equal to 3 cm(-1)) at lambda(0) = 1.3 and 1.55 mu m, secondary ion mass spectrometry depth profile, and Fourier transform infrared transmission spectra measurements are presented to characterize a multimode single-heterostructure oxide waveguide. An index contrast of Delta n = 0.06 is observed between oxidized x = 0.4 and x = 0.8 AlxGa1-xAs oxide layers. Absorption loss at 1.55 mu m is observed due to OH groups. Near-field images are presented showing waveguiding in a single-mode oxide double heterostructure. (C) 1999 American Institute of Physics. [S0003-6951(99)05446-7]. C1 Univ Notre Dame, Dept Elect Engn, Notre Dame, IN 46556 USA. Metricon Corp, Pennington, NJ 08534 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Luo, Y (reprint author), Univ Notre Dame, Dept Elect Engn, Notre Dame, IN 46556 USA. NR 13 TC 13 Z9 13 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 NOV 15 PY 1999 VL 75 IS 20 BP 3078 EP 3080 DI 10.1063/1.125236 PG 3 WC Physics, Applied SC Physics GA 254NV UT WOS:000083619800010 ER PT J AU Misra, A Nastasi, M AF Misra, A Nastasi, M TI Limits of residual stress in Cr films sputter deposited on biased substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID POLYCRYSTALLINE THIN-FILMS; ION-ASSISTED DEPOSITION; INTRINSIC STRESS; PLASTIC-FLOW; BOMBARDMENT AB Stress evolution in thin Cr films on Si substrates is studied as a function of substrate bias. With increasing bias voltage, the tensile stress is observed to increase to a maximum, transition to compressive stress that also reaches a maximum. We relate the tensile stress maximum to the maximum in attractive interatomic forces between the coalescing islands, and the compressive stress maximum to the saturation in Frenkel defect concentration, with smaller contribution from entrapped Ar. We show that the maxima in both tensile and compressive residual stress correspond to the film yield strength. Compressive yield strength is higher as compared to tensile due to hardening from point defects. (C) 1999 American Institute of Physics. [S0003-6951(99)04045-0]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Misra, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 27 TC 20 Z9 20 U1 0 U2 9 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 NOV 15 PY 1999 VL 75 IS 20 BP 3123 EP 3125 DI 10.1063/1.125251 PG 3 WC Physics, Applied SC Physics GA 254NV UT WOS:000083619800025 ER PT J AU Heron, RJ Lewis, RA Kane, BE Facer, GR Clark, RG Dzurak, AS Lumpkin, NE Starrett, RP Rickel, DG Pfeiffer, LN West, KW AF Heron, RJ Lewis, RA Kane, BE Facer, GR Clark, RG Dzurak, AS Lumpkin, NE Starrett, RP Rickel, DG Pfeiffer, LN West, KW TI Quantum point contact in a magnetic field: Far-infrared resonant heating observed in photoconductivity SO APPLIED PHYSICS LETTERS LA English DT Article ID QUANTIZED CONDUCTANCE; WIRES; TRANSPORT AB We report on the far-infrared photoresponse of a quantum point contact device fabricated on a top-gated GaAs/AlGaAs heterostructure. The top-gated architecture avoids the disorder built into conventional modulation-doped structures. We observe a distinctive far-infrared magnetophotoresponse. This depends on the wavelength of the radiation and on the carrier density, which is controlled by the gate voltage. We conclude by comparison with transport data that the oscillations observed in photoconductivity and which are centred around the cyclotron energy arise from the resonant heating of electrons by the far-infrared radiation. (C) 1999 American Institute of Physics. [S0003-6951(99)03346-X]. C1 Univ Wollongong, Dept Phys, Wollongong, NSW 2522, Australia. Univ New S Wales, Semicond Nanofabricat Facil, Sydney, NSW 2052, Australia. Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Univ Wollongong, Dept Phys, Wollongong, NSW 2522, Australia. EM r.lewis@uow.edu RI Dzurak, Andrew/C-5973-2009; Lewis, Roger/D-3135-2014 OI Lewis, Roger/0000-0002-4598-7553 NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 15 PY 1999 VL 75 IS 20 BP 3150 EP 3152 DI 10.1063/1.125260 PG 3 WC Physics, Applied SC Physics GA 254NV UT WOS:000083619800034 ER PT J AU Krishnamurthy, S Berding, MA Sher, A van Schilfgaarde, M Chen, AB AF Krishnamurthy, S Berding, MA Sher, A van Schilfgaarde, M Chen, AB TI Direct gap in ordered silicon carbon alloys SO APPLIED PHYSICS LETTERS LA English DT Article ID SI-GE SUPERLATTICES; OPTICAL-TRANSITIONS; SEMICONDUCTOR ALLOYS; SI(001); GROWTH AB We show that alloying silicon with a few percent of carbon can render the band gap direct with strong optical absorption, provided the carbon atoms are ordered. The addition of carbon introduces a significant s character into the conduction band minimum, resulting in a large dipole matrix element. First-principles calculations of the optical absorption in ordered in CxSi1-x alloys for x = 1/54 and 1/32 show a near band edge absorption coefficient about half that of GaAs. (C) 1999 American Institute of Physics. [S0003-6951(99)03845-0]. C1 SRI Int, Menlo Park, CA 94025 USA. Sandia Natl Labs, Livermore, CA 94550 USA. Auburn Univ, Dept Phys, Auburn, AL 36849 USA. RP Krishnamurthy, S (reprint author), SRI Int, 333 Ravenswood Ave, Menlo Park, CA 94025 USA. NR 25 TC 8 Z9 8 U1 0 U2 0 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 NOV 15 PY 1999 VL 75 IS 20 BP 3153 EP 3155 DI 10.1063/1.125261 PG 3 WC Physics, Applied SC Physics GA 254NV UT WOS:000083619800035 ER PT J AU Schnyders, HS Saboungi, ML Enderby, JE AF Schnyders, HS Saboungi, ML Enderby, JE TI Noninvasive simultaneous determination of conductivity and permeability SO APPLIED PHYSICS LETTERS LA English DT Article AB Simultaneous measurements of both the conductivity and permeability are presented using noninvasive methods based on inductive coupling. Explicit expressions for cylindrical and spherical geometries are derived. The technique, especially relevant to liquids and solids in extreme environments, will also be valuable for nanomaterials and other systems where external contacts are difficult to establish. (C) 1999 American Institute of Physics. [S0003-6951(99)02046-X]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. RP Schnyders, HS (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 7 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 15 PY 1999 VL 75 IS 20 BP 3213 EP 3215 DI 10.1063/1.125281 PG 3 WC Physics, Applied SC Physics GA 254NV UT WOS:000083619800054 ER PT J AU Boultwood, J Fidler, C Strickson, AJ Watkins, F Kostrzewa, M Jaju, RJ Muller, U Jabs, EW Cheng, JF Wainscoat, JS AF Boultwood, J Fidler, C Strickson, AJ Watkins, F Kostrzewa, M Jaju, RJ Muller, U Jabs, EW Cheng, JF Wainscoat, JS TI Isolation and analysis of novel candidate genes mapping to the critical region of the 5q-syndrome. SO BLOOD LA English DT Meeting Abstract C1 John Radcliffe Hosp, Dept Cellular Sci, LRF Mol Haematol Unit, Oxford OX3 9DU, England. Inst Humangenet, Giessen, Germany. Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 4042 BP 188B EP 188B PN 2 PG 1 WC Hematology SC Hematology GA 257PM UT WOS:000083790700868 ER PT J AU Auffray, I de Jong, K Kuypers, FA Huang, CH Chasis, J Mohandas, N AF Auffray, I de Jong, K Kuypers, FA Huang, CH Chasis, J Mohandas, N TI The expression of murine glycophorin a is decreased in red blood cells of human glycophorin a transgenic mice: In vivo evidence for glycophorin A-band 3 interaction during erythroid membrane biogenesis. SO BLOOD LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Childrens Hosp, Oakland Res Inst, Oakland, CA 94609 USA. New York Blood Ctr, Lindsley F Kimball Res Inst, New York, NY 10021 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 824 BP 189A EP 189A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790300873 ER PT J AU de Jong, K Emerson, RK Butler, J Mohandas, N Kuypers, FA AF de Jong, K Emerson, RK Butler, J Mohandas, N Kuypers, FA TI Ineffective erythropoiesis in sickle cell mice. SO BLOOD LA English DT Meeting Abstract C1 Childrens Hosp Oakland, Res Inst, Oakland, CA 94609 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 857 BP 196A EP 196A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790300906 ER PT J AU Croisille, L Chiron, M Vainchenker, W Romeo, PH Rince, P Willig, TN Tchernia, G AF Croisille, L Chiron, M Vainchenker, W Romeo, PH Rince, P Willig, TN Tchernia, G TI Diamond-Blackfan anemia with mutations in RPS19 gene: A different pattern of in vitro erythroid differentiation? SO BLOOD LA English DT Meeting Abstract C1 Hop Kremlin Bicetre, Dept Hematol, Paris, France. IGR, INSERM U362, Villejuif, France. Hop Henri Mondor, INSERM U474, F-94010 Creteil, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Human Genome, Berkeley, CA 94720 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 1834 BP 414A EP 414A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790301883 ER PT J AU Punzalan, RC Holzman, S Trost, BA Paszty, C Narla, M Scott, JP Hillery, CA AF Punzalan, RC Holzman, S Trost, BA Paszty, C Narla, M Scott, JP Hillery, CA TI Spontaneous stroke and increased erythrocyte adhesion in transgenic knockout sickle cell mice. SO BLOOD LA English DT Meeting Abstract C1 Med Coll Wisconsin, Dept Pediat, Milwaukee, WI 53226 USA. Med Coll Wisconsin, Dept Pathol, Milwaukee, WI 53226 USA. Blood Ctr SE Wisconsin Inc, Blood Res Inst, Milwaukee, WI 53233 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Human Genome, Berkeley, CA 94720 USA. NR 0 TC 3 Z9 3 U1 1 U2 1 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 1857 BP 419A EP 419A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790301906 ER PT J AU Fabry, ME Suzuka, SM Gilman, JG Costantini, FD Paszty, C Smithies, O Nagel, RL AF Fabry, ME Suzuka, SM Gilman, JG Costantini, FD Paszty, C Smithies, O Nagel, RL TI Second generation knock-out sickle mice are useful for validation of gene therapy strategies. SO BLOOD LA English DT Meeting Abstract C1 Albert Einstein Coll Med, Div Hematol, Bronx, NY 10467 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ N Carolina, Chapel Hill, NC USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 2866 BP 645A EP 645A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790302915 ER PT J AU Chasis, J Parsons, S Gimm, A Spring, F Lee, G Anstee, D Mohandas, N AF Chasis, J Parsons, S Gimm, A Spring, F Lee, G Anstee, D Mohandas, N TI Binding interactions of extracellular and cytoplasmic domains of erythrocyte adhesion protein lutheran. SO BLOOD LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. Bristol Inst Transfus Sci, Bristol, Avon, England. NR 0 TC 3 Z9 3 U1 1 U2 1 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 2977 BP 671A EP 671A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790303026 ER PT J AU Hou, VC Gee, S Wu, M Lersch, R Conboy, JG AF Hou, VC Gee, S Wu, M Lersch, R Conboy, JG TI Alternative splicing of protein 4.1 exon 16 is regulated in part through coordinated activity of exon splicing enhancer and silencer elements. SO BLOOD LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 2978 BP 672A EP 672A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790303027 ER PT J AU Gazda, H Lipton, JM Niemeyer, CM Willig, TN Tchernia, G Narla, M Ploszynska, A Vlachos, A Glader, BE Rokicka-Milewska, R Ohara, A Baker, D Webber, A Viskochil, DH Nathan, DG Beggs, AH Sieff, CA AF Gazda, H Lipton, JM Niemeyer, CM Willig, TN Tchernia, G Narla, M Ploszynska, A Vlachos, A Glader, BE Rokicka-Milewska, R Ohara, A Baker, D Webber, A Viskochil, DH Nathan, DG Beggs, AH Sieff, CA TI Evidence for linkage of familial Diamond-Blackfan Anemia to chromosome 8p23.2-23.1 and for non-19q non-8p disease. SO BLOOD LA English DT Meeting Abstract C1 Harvard Univ, Sch Med, Dana Farber Canc Inst, Boston, MA 02115 USA. Harvard Univ, Sch Med, Childrens Hosp, Boston, MA 02115 USA. CUNY Mt Sinai Sch Med, Div Pediat Hematol Oncol, New York, NY 10029 USA. Univ Freiburg, Childrens Hosp, D-7800 Freiburg, Germany. Hop Bicetre, Dept Hematol, Kremlin Bicetre, France. LBNL, Berkeley, CA USA. Univ Gdansk, Dept Pediat Hematol Oncol, PL-80952 Gdansk, Poland. Stanford Univ, Div Pediat Hematol Oncol, Sch Med, Stanford, CA 94305 USA. Warsaw Sch Med, Dept Pediat Hematol Oncol, Warsaw, Poland. Toho Univ, Sch Med, Dept Pediat, Tokyo, Japan. Princess Margaret Hosp Children, Dept Pediat Haematol Oncol, Perth, WA, Australia. Univ Utah, Sch Med, Div Med Genet, Salt Lake City, UT 84112 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 2983 BP 673A EP 673A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790303032 ER PT J AU Kaul, DK Fabry, ME Paszty, C Liu, XD Nagel, RL AF Kaul, DK Fabry, ME Paszty, C Liu, XD Nagel, RL TI Pronounced vascular tone and hemodynamic alterations in transgenic knockout sickle mice are ameliorated in a knockout sickle mouse line expressing anti-sickling gamma-globin. SO BLOOD LA English DT Meeting Abstract C1 Albert Einstein Coll Med, Bronx, NY 10467 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 15 PY 1999 VL 94 IS 10 SU 1 MA 2996 BP 676A EP 676A PN 1 PG 1 WC Hematology SC Hematology GA 257PH UT WOS:000083790303045 ER PT J AU Liu, WM Guerra-Vladusic, FK Kurakata, S Lupu, R Kohwi-Shigematsu, T AF Liu, WM Guerra-Vladusic, FK Kurakata, S Lupu, R Kohwi-Shigematsu, T TI HMG-I(Y) recognizes base-unpairing regions of matrix attachment sequences and its increased expression is directly linked to metastatic breast cancer phenotype SO CANCER RESEARCH LA English DT Article ID PROTEIN HMG-I; DNA-BINDING PROTEIN; CHROMOSOMAL LOOP ANCHORAGE; EPIDERMAL GROWTH-FACTOR; MOBILITY-GROUP PROTEINS; NUCLEAR MATRIX; NEU-ONCOGENE; DEPENDENT TRANSCRIPTION; PROGNOSTIC-SIGNIFICANCE; PROGRESSION MARKER AB Base-unpairing regions (SURs) contain a specialized DNA context with an exceptionally high unwinding propensity, and are typically identified within various matrix attachment regions. A BUR affinity column was used to purify a doublet of M-r 20,000 proteins from human breast carcinoma cells. These proteins were identified as the high-mobility group (HMG) protein, HMG-I, and its splicing variant, HMG-Y. We show that HMG-I(Y) specifically binds BURs. Mutating BURs so as to abrogate their unwinding property greatly reduced their binding affinity to HMG-I(Y), Numerous studies have indicated that elevated HMG-I(Y) expression is correlated with more advanced cancers and with increased metastatic potential. We studied whether the expression of HMG-I(Y) responds to signaling through the heregulin (HRG)-erbB pathway and the extracellular matrix. HMG-I(Y) expression was increased in MCF-7 cells after stable transfection with an HRG expression construct that led cells to acquire estrogen independence and metastasizing ability. A high level of HMG-I(Y) expression was detected in metastatic MDA-MB-231 cells, but the expression was virtually diminished, and the metastasizing ability was lost after cells were stably transfected with an antisense HRG cDNA construct. HMG-I(Y) was also decreased in MDA-MB-231 cells when treated with a chemical inhibitor for matrix metalloproteinase-9 that led to a reduction of invasive capability in vitro. The level of HMG-I(Y) expression, therefore, is dynamically regulated in human breast cancer cells in response to varying types of signaling that affect metastatic ability, including the HRG-erbB pathway and those from the extracellular matrix. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Sankyo Co Ltd, Biol Res Labs, Shinagawa Ku, Tokyo 140, Japan. RP Kohwi-Shigematsu, T (reprint author), Univ Calif Berkeley, Berkeley Natl Lab, 1 Cyclotron Rd,70A-1118, Berkeley, CA 94720 USA. FU NCI NIH HHS [R03 CA70824]; NIDDK NIH HHS [R01-DK-49049] NR 88 TC 53 Z9 53 U1 0 U2 0 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD NOV 15 PY 1999 VL 59 IS 22 BP 5695 EP 5703 PG 9 WC Oncology SC Oncology GA 258RQ UT WOS:000083853300013 PM 10582687 ER PT J AU Lazar, A Reilly, PTA Whitten, WB Ramsey, JM AF Lazar, A Reilly, PTA Whitten, WB Ramsey, JM TI Real-time surface analysis of individual airborne environmental particles SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID FLIGHT MASS-SPECTROMETRY; AEROSOL-PARTICLES; CHEMICAL-ANALYSIS; AROMATIC-HYDROCARBONS; MICROPARTICLES; IONIZATION AB Typically, in real-time aerosol mass spectrometry (RTAMS), individual airborne particles are ablated and ionized with a single focused laser pulse. This technique yields information that permits bulk characterization of the particle, but information about the particle's surface is often masked or diluted by the particle bulk. Here we show that it is possible to probe the surface composition of individual airborne particles by separating the desorption and ionization steps using a two-laser real-time aerosol mass spectrometry technique (L2RTAMS). First, a weak excimer laser pulse was used to desorb the semivolatile components of the particle surface when the particle was in the center of the ion trap. After a short delay, another excimer laser pulse was used to ionize the semivolatile surface components in the gas phase and subsequently mass analyzed. The results from the one- and two-laser techniques were compared and found to be complementary. The L2RTAMS technique was found very sensitive to polycyclic aromatic hydrocarbons (PAHs). PAHs, of the type emitted from diesel engines, were found on particle surfaces of National Institute of Standards and Technology (NIST) standard reference materials (SRMs) from Indiana Harbor Canal (1645) and urban particulate matter (1648). PAH partitioning on the environmental particles is discussed. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Reilly, PTA (reprint author), Oak Ridge Natl Lab, POB 2008,M-S 6142, Oak Ridge, TN 37831 USA. NR 27 TC 26 Z9 27 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD NOV 15 PY 1999 VL 33 IS 22 BP 3993 EP 4001 DI 10.1021/es9905849 PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255UQ UT WOS:000083688900007 ER PT J AU Urrutia, MM Roden, EE Zachara, JM AF Urrutia, MM Roden, EE Zachara, JM TI Influence of aqueous and solid-phase Fe(II) complexants on microbial reduction of crystalline iron(III) oxides SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID METAL-EDTA COMPLEXES; ADSORPTION; IRON; DISSOLUTION; ETHYLENEDIAMINETETRAACETATE; CONTAMINANTS; SEDIMENTS; OXIDATION; MANGANESE; COATINGS AB The influence of aqueous (NTA and EDTA) and solid-phase (aluminum oxide, layer silicates) Fe(II) complexants on the long-term microbial reduction of synthetic goethite by Shewanella alga strain BrY was studied. NTA enhanced goethite reduction by promoting aqueous Fe(II) accumulation, in direct proportion Po its concentration in culture medium (0.01-5 mM). In contrast EDTA failed to stimulate goethite reduction at concentrations less than or equal to 1 mM, and 5 mM EDTA enhanced the final extent of reduction by only 25% in relation to nonchelator controls. The minor effect of EDTA compared to NTA, despite the greater stability of the Fe(II)EDTA complex, likely resulted from sorption of Fe(II)EDTA complexes to goethite, Equilibrium Fe(II) speciation calculations showed that Fe(II)(aq) should increase with NTA at the expense of the solid-phase Fe(II) species, whereas the opposite trend was true for EDTA due to Fe(II)EDTA adsorption. The presence of aluminum oxide and layer silicates led to a variable but significant (1.5 to > 3-fold) increase in the extent of goethite reduction. Speciation of Fe(II) verified the binding of Fe(II) by these solid-phase materials. Our results support the hypothesis that iron(III) oxide reduction may be enhanced by aqueous or solid-phase compounds which prevent or delay Fe(II) sorption to oxide and FeRB cell surfaces. C1 Univ Alabama, Dept Biol Sci, Tuscaloosa, AL 35487 USA. Pacific NW Lab, Environm Dynam & Simulat Dept, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Urrutia, MM (reprint author), Univ Alabama, Dept Biol Sci, Box 870206, Tuscaloosa, AL 35487 USA. NR 26 TC 107 Z9 113 U1 5 U2 29 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 NOV 15 PY 1999 VL 33 IS 22 BP 4022 EP 4028 DI 10.1021/es990447b PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255UQ UT WOS:000083688900011 ER PT J AU Nelson, NT Oostrom, M Wietsma, TW Brusseau, ML AF Nelson, NT Oostrom, M Wietsma, TW Brusseau, ML TI Partitioning tracer method for the in situ measurement of DNAPL saturation: Influence of heterogeneity and sampling method SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID POROUS-MEDIA; LIQUID AB The purpose of this work was to examine the effect of porous-media heterogeneity, nonuniform distribution of dense nonaqueous phase liquid (DNAPL), and sampling method on the performance of the partitioning tracer method for measuring DNAPL saturation in water-saturated subsurface systems. Experiments were conducted in an intermediate-scale flow cell that contained two discrete zones of trichloroethene (TCE) at residual saturation. One zone (zone 2) consisted of similar to 10% saturation formed in the same sand as used for the flow-cell matrix. The other zone (zone 1) consisted of similar to 10% saturation in a finer sand emplaced within the coarser matrix. Aqueous samples were collected using depth-specific sampling, using vertically integrated sampling, and at the extraction well. A dual-energy gamma radiation system was used to measure TCE saturation before and after the tracer experiment, allowing the measurements obtained from the tracer experiment to be compared to a previously tested method. The saturations estimated using the data collected at paint-sampling ports located downgradient of zones 1 and 2 were approximately 7% and 50% of the true values, respectively. The saturations estimated using the data obtained from the vertically integrated ports were 0% and 6% of the true values, respectively. Finally, the saturation estimated using the extraction-well data was 30% of the cell-wide averaged value. These results indicate that the presence of porous-media heterogeneity and a variable distribution of DNAPL saturation can lead to reduced accuracy of the partitioning tracer test. The reduced performance can be improved, in part, by using depth-specific sampling. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Univ Arizona, Dept Soil Water & Environm Sci, Tucson, AZ 85721 USA. Pacific NW Lab, Environm Technol Div, Richland, WA 99352 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Brusseau, ML (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Shantz Bldg,Room 429, Tucson, AZ 85721 USA. NR 22 TC 33 Z9 34 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD NOV 15 PY 1999 VL 33 IS 22 BP 4046 EP 4053 DI 10.1021/es990022p PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255UQ UT WOS:000083688900015 ER PT J AU Conrad, ME Templeton, AS Daley, PF Alvarez-Cohen, L AF Conrad, ME Templeton, AS Daley, PF Alvarez-Cohen, L TI Seasonally-induced fluctuations in microbial production and consumption of methane during bioremediation of aged subsurface refinery contamination SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CARBON-ISOTOPE; CRUDE-OIL; ANAEROBIC DEGRADATION; REDUCING CONDITIONS; OXIDATION; BIODEGRADATION; SOIL; FRACTIONATION; HYDROCARBONS; ACETATE AB Intrinsic bioremediation of 90-130 year old refinery wastes in shallow, saturated soils was studied over a 1-year period by measuring the compositions and isotopic ratios of soil gas and groundwater samples. CH4 concentrations in soil gas samples from areas with high residual refinery waste concentrations were found to fluctuate greatly in response to seasonal changes in groundwater levels. The C-14 content of the CH4 was low (0.03-0.10 times modern), indicating that it was predominantly formed from the refinery wastes. The delta(13)C and delta D values of the CH4 were consistent with formation via acetate fermentation. The source of the acetate to drive this reaction is not clear but could be due to either aerobic degradation of the hydrocarbons caused by influx of oxygen-enriched rainwater or anaerobic hydrocarbon degradation. In the vadose zone, the delta(13)C and delta D values of the CH4 increased as its concentration decreased, indicating that the CH4 was being oxidized by methanotrophic bacteria. This is confirmed by large decreases in the delta(13)C values and C-14 content of coexisting CO2. The results of this study show that soil microorganisms can utilize highly weathered hydrocarbons to produce significant concentrations of CH4. They also demonstrate how easily misleading conclusions about levels of intrinsic bioremediation can be drawn from spatially or temporally limited sample sets. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Div Environm Restorat, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RP Conrad, ME (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, MS 70A-3363, Berkeley, CA 94720 USA. EM MSConrad@lbl.gov RI Conrad, Mark/G-2767-2010; OI TEMPLETON, ALEXIS/0000-0002-9670-0647 NR 48 TC 21 Z9 22 U1 1 U2 7 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 NOV 15 PY 1999 VL 33 IS 22 BP 4061 EP 4068 DI 10.1021/es990582o PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255UQ UT WOS:000083688900017 ER PT J AU Thornton, EC Amonette, JE AF Thornton, EC Amonette, JE TI Hydrogen sulfide gas treatment of Cr(VI)-contaminated sediment samples from a plating-waste disposal site - Implications for in-situ remediation SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB Twenty sediment samples were collected at depths ranging from 5 to 100 feet beneath a chromate-contaminated plating-waste sire and analyzed for Cr(VI), total chromium, and related constituents. Three of the samples were selected for treatment with dilute hydrogen sulfide (H2S) gas to evaluate this approach as a possible in-situ remediation technique. Gas treatment was performed in soil-packed columns using 100 ppm (mu L L-1) H2S mixtures, and treatment progress was assessed by monitoring the breakthrough of H2S. Evaluation of treatment efficacy included (1) water-leaching of the treated and untreated columns for 10 days, (2) repetitive extraction of treated and untreated subsamples by water, 0.01 M phosphate (pH 7) or 6 M HCl solutions, and (3) Cr K-edge X-ray absorption near-edge structure (XANES) spectroscopy of treated and untreated subsamples. Results of the water-leaching studies showed that the H2S treatment decreased Cr(VI) levels in the column effluent by 90% to nearly 100%. Repetitive extractions by water and phosphate solutions echoed these results, and the extraction by HCl released only 35-40% as much Cr in the treated as in the untreated samples. Analysis by XANES spectroscopy showed that a substantial portion of the Cr in the samples remained as Cr(VI) after treatment, even though it was not available to the water and phosphate extracting solutions. These results indicate that the residual Cr(VI) was sequestered in unreacted grain interiors under impermeable coatings formed during H2S treatment However, this fraction is immobile and thus unavailable to the environment. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Thornton, EC (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 23 TC 73 Z9 78 U1 3 U2 21 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 NOV 15 PY 1999 VL 33 IS 22 BP 4096 EP 4101 DI 10.1021/es9812507 PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255UQ UT WOS:000083688900023 ER PT J AU Regueiro, RA Borja, RI AF Regueiro, RA Borja, RI TI A finite element model of localized deformation in frictional materials taking a strong discontinuity approach SO FINITE ELEMENTS IN ANALYSIS AND DESIGN LA English DT Article ID DYNAMIC STRAIN LOCALIZATION; ONE-DIMENSIONAL EXAMPLES; GRANULAR MEDIA; PLANE-STRAIN; ELASTO-(VISCO-)PLASTIC SOLIDS; LOADING CONDITIONS; COMPRESSION TESTS; CIRCULAR DISKS; SOIL MECHANICS; SHEAR BANDS AB A finite element model of localized deformation in frictional materials taking a strong discontinuity approach is presented. A rate-independent, non-associated, strain-softening Drucker-Prager plasticity model is formulated in the context of strong discontinuities and implemented along with an enhanced quadrilateral element within the framework of an assumed enhanced strain finite element method. For simple model problems such as uniform compression, the strong discontinuity approach has been shown to lead to mesh-independent finite element solutions when localized deformation is present. In this paper, a finite element analysis of localized deformation occurring in a more complex model problem of slope stability is conducted in a nearly mesh-independent manner. The effect of dilatancy on the orientation of slip lines is demonstrated for the slope stability problem. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Dept Civil & Environm Engn, Stanford, CA 94305 USA. RP Regueiro, RA (reprint author), Sandia Natl Labs, POB 969, Livermore, CA 94551 USA. OI Regueiro, Richard/0000-0002-1669-1753 NR 75 TC 43 Z9 47 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-874X J9 FINITE ELEM ANAL DES JI Finite Elem. Anal. Des. PD NOV 15 PY 1999 VL 33 IS 4 BP 283 EP 315 DI 10.1016/S0168-874X(99)00050-5 PG 33 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA 263ME UT WOS:000084127800006 ER PT J AU Mak, JE Brenninkmeijer, CAM Southon, JR AF Mak, JE Brenninkmeijer, CAM Southon, JR TI Direct measurement of the production rate of C-14 near Earth's surface SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERE; ABUNDANCE; (CO)-C-14 AB Environmental C-14 is well known for its application in carbon dating organic material, as well as its use as a geochemical tracer in the oceans and atmosphere; More recently,C-14 in the form of atmospheric (CO)-C-14 has been used to estimate the concentration of hydroxyl radical, which is the primary oxidant of the atmosphere. This latter application is dependent upon accurate knowledge of the cosmogenic production rate, which has been calculated, but not directly measured. We have measured the atmospheric production rate of C-14 near the earth's surface on a 300-meter research tower in Colorado, at the South Pole, at Scott Base, Antarctica, and near Mount Cook, New Zealand. The observed production rate near the surface was 50% of the production rate calculated by an earlier study. We also find that the 'ground effect', which causes an increase in the thermal neutron flux resulting in an enhancement of the production rate of C-14, is significantly smaller than calculated in earlier studies. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Max Planck Inst Chem, D-55020 Mainz, Germany. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Mak, JE (reprint author), SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. RI Brenninkmeijer, Carl/B-6860-2013 NR 24 TC 7 Z9 7 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 NOV 15 PY 1999 VL 26 IS 22 BP 3381 EP 3384 DI 10.1029/1999GL010791 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 255PC UT WOS:000083677500013 ER PT J AU Lahti, DW Espenson, JH AF Lahti, DW Espenson, JH TI Kinetics and mechanism of oxygen atom abstraction from sulfenatocobalt(III) complexes by hydrated methyldioxorhenium(V) SO INORGANIC CHEMISTRY LA English DT Article ID COORDINATED SULFENIC ACIDS; HYDROGEN-PEROXIDE; OXIDATION; THIOLATE; OXIDES; SULFUR AB Cationic sulfenatocobalt(III) complexes, with the remaining ligands amines, are deoxygenated upon reaction with hydrated methyldioxorhenium(V). The reactions of (Am)(5)Co-S(O)R2+ yield the thiolato complexes (Am)(5)Co-SR2+ and methyltrioxorhenium(VII), MTO. A kinetic study of these reactions was carried out, using the known reaction between MTO and hypophosphorous acid to prepare the Re(V) reagent in solution. The second-order rate constants between (Am)(5)Co-S(O)R2+ and MeReO2(aq), after correction for protonation, fall in the range 47-455 L mol(-1) s(-1) in aqueous solution at 25.0 degrees C and 1.0 M ionic strength. In the analysis of the pH effects, allowance was made for the formation of the protonated species (Am)(5)Co-S(OH)R3+ at high [H3O+]. The values of pK(a) are in the range 0.49-0.96, as determined from fitting the rate-pH profiles. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 22 TC 7 Z9 7 U1 0 U2 2 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 NOV 15 PY 1999 VL 38 IS 23 BP 5230 EP 5234 DI 10.1021/ic990425q PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 256ZA UT WOS:000083755300006 ER PT J AU Chen, XY Ji, M Fisher, DR Wai, CM AF Chen, XY Ji, M Fisher, DR Wai, CM TI Ionizable calixarene-crown ethers with high selectivity for radium over light alkaline earth metal ions SO INORGANIC CHEMISTRY LA English DT Article ID SOLVENT-EXTRACTION; MONOCLONAL-ANTIBODIES; BIOLOGICAL-SYSTEMS; CATIONS; COMPLEXATION; ACID; RADIOIMMUNOTHERAPY; RADIONUCLIDES; CHLOROFORM; TRANSPORT AB Two new ionizable calixarene-crown ethers, p-tert-butylcalix[4]arene-crown-6-dicarboxylic acid (3) and p-tert-butylcalix[4]arene-crown-6-dihydroxamic acid (4) with preorganized ionophoric cavities, exhibit high selectivity for Ra-223 over lighter alkaline earth metal ions. The ionizable calixcrowns show promising binding properties for developing a Ra-223-based alpha-emitter radioimmunotherapy. C1 Univ Idaho, Dept Chem, Moscow, ID 83844 USA. Pacific NW Lab, Hanford Radioisotopes & Med Sci Program, Richland, WA 99352 USA. RP Wai, CM (reprint author), Univ Idaho, Dept Chem, Moscow, ID 83844 USA. NR 41 TC 20 Z9 21 U1 0 U2 6 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 NOV 15 PY 1999 VL 38 IS 23 BP 5449 EP + DI 10.1021/ic990135+ PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 256ZA UT WOS:000083755300036 ER PT J AU Crone, BK Campbell, IH Davids, PS Smith, DL Neef, CJ Ferraris, JP AF Crone, BK Campbell, IH Davids, PS Smith, DL Neef, CJ Ferraris, JP TI Device physics of single layer organic light-emitting diodes SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CONJUGATED POLYMERS; ELECTRON; FILMS; MODEL AB We present experimental and device model results for electron only, hole only, and bipolar organic light-emitting diodes fabricated using a soluble poly (p-phenylene vinylene) based polymer. Current-voltage (I-V) characteristics were measured for a series of electron only devices in which the polymer thickness was varied. The I-V curves were described using a device model from which the electron mobility parameters were extracted. Similarly, the hole mobility parameters were extracted using a device model description of I-V characteristics for a series of hole only devices where the barrier to hole injection was varied by appropriate choices of hole injecting electrode. The electron and hole mobilities extracted from the single carrier devices are then used, without additional adjustable parameters, to describe the measured current-voltage characteristics of a series of bipolar devices where both the device thickness and contacts were varied. The model successfully describes the I-V characteristics of single carrier and bipolar devices as a function of polymer thickness and for structures that are contact limited, space charge limited, and for cases in between. We find qualitative agreement between the device model and measured external luminance for a thickness series of devices. We investigate the sensitivity of the device model calculations to the magnitude of the bimolecular recombination rate prefactor. (C) 1999 American Institute of Physics. [S0021-8979(99)05922-8]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Texas, Richardson, TX 75080 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 67 Z9 67 U1 0 U2 15 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 NOV 15 PY 1999 VL 86 IS 10 BP 5767 EP 5774 DI 10.1063/1.371591 PG 8 WC Physics, Applied SC Physics GA 251GH UT WOS:000083435900066 ER PT J AU Li, D Nishijima, A Morris, DE Guthrie, GD AF Li, D Nishijima, A Morris, DE Guthrie, GD TI Activity and structure of hydrotreating Ni, Mo, and Ni-Mo sulfide catalysts supported on gamma-Al2O3-USY zeolite SO JOURNAL OF CATALYSIS LA English DT Article DE Ni-Mo/gamma-Al2O3-USY zeolite; hydrocracking; hydrodesulfurization; NH3 temperature-programmed desorption; X-ray photoelectron spectroscopy; diffuse reflectance spectroscopy ID NI-MO/GAMMA-AL2O3-B2O3 CATALYSTS; HYDROGEN SPILLOVER; HYBRID CATALYSTS; LATTICE OXYGENS; ALUMINA; ADSORPTION; MECHANISM; NICKEL; IONS; HYDROCRACKING AB The catalytic hydrocracking (HC) of diphenylmethane (DPM) and hydrodesulfurization (HDS) of dibenzothiophene (DBT) over Ni, Mo, and Ni-Mo sulfide catalysts supported on a mixed ultrastable Y (USY) zeolite and gamma-Al2O3 were studied. The catalysts were characterized using NH3 temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), and chemical composition analysis. Because addition of zeolite to a conventional alumina support improves acidity, Ni, Mo, and Ni-Mo catalysts supported on the combined supports had much higher HC activity. Ni was found to be uniformly distributed throughout the catalysts; however, Mo preferentially entered the structure of gamma-Al2O3 or was accommodated as oxide aggregates on gamma-Al2O3, rather than associating with zeolite. Ni and Mo catalysts supported on gamma-Al2O3-USY zeolite were good HDS catalysts and showed a shallow maximum in catalytic activity at a NiO and MoO3 content of 5 mol%. The higher activity at this content occurred because Ni or Mo species had higher surface concentrations, higher dispersion, and were more easily sulfided, Ni-Mo catalysts supported on gamma-Al2O3-USY zeolite had high HDS activity, which showed a prominent maximum at a NiO/(NiO + MoO3) ratio of about 0.4, because at this ratio the surface species of Ni and Mo were well dispersed and more easily sulfided to form a Ni-Mo-S phase responsible for the high HDS activity. The Ni-Mo catalysts supported on gamma-Al2O3-USY zeolite have slightly higher HDS activity than gamma-Al2O3-supported Ni-Mo catalysts. (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Natl Inst Mat & Chem Res, Dept Surface Chem, Tsukuba, Ibaraki 305, Japan. RP Li, D (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, EES-1,MS D462, Los Alamos, NM 87545 USA. RI Morris, David/A-8577-2012; Li, Dien/N-6370-2014 NR 31 TC 43 Z9 49 U1 7 U2 37 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD NOV 15 PY 1999 VL 188 IS 1 BP 111 EP 124 DI 10.1006/jcat.1999.2663 PG 14 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 256HC UT WOS:000083719000012 ER PT J AU Au-Yeung, J Chen, KD Bell, AT Iglesia, E AF Au-Yeung, J Chen, KD Bell, AT Iglesia, E TI Isotopic studies of methane oxidation pathways on PdO catalysts SO JOURNAL OF CATALYSIS LA English DT Article AB Mechanistic details of CH4 oxidation were examined on PdO/ZrO2 catalysts using isotopic tracer methods and measurements of kinetic isotope effects. Normal kinetic isotope effects were observed using CH4/O-2 and CD4/O-2 reactant mixtures. The (k(H)/k(D)) ratio was between 2.6 and 2.5, and it decreased slightly as the reaction temperature increased from 527 to 586 K. These kinetic isotope effects reflect a combination of kinetic and thermodynamic effects, and the measured values are consistent with rate-determining C-H bond activation steps on surfaces predominantly covered with OH groups. Isotopic equilibration rates for CH4/CD4/O-2 mixtures were much lower than methane combustion rates, suggesting that C-H bond activation steps are irreversible on PdO at 473-600 K. Reactions of CH4/O-18(2) mixtures on pd(16)O-(ZrO2)-O-16 led to the initial formation of (CO2)-O-16, followed by a gradual increase in the concentration of other CO2 isotopomers as lattice O-16 atoms are replaced by O-18 from O-18(2). The involvement of lattice oxygens in C-H bond activation steps is consistent with a Mars-van Krevelen redox mechanism. Reactions of CH4/O-16(2)/O-18(2) mixtures lead to all CO2 isotopomers without the concurrent formation of (OO)-O-16-O-18. Thus, dissociative oxygen chemisorption is also irreversible during methane combustion. Oxygen atoms in (CO2)-O-16 exchange with (PdO)-O-18-(ZrO2)-O-18 catalysts at temperatures lower than those required for methane combustion, suggesting that CO2 desorption is quasi-equilibrated. These mechanistic conclusions are consistent with the measured dependence of CH4 oxidation rates on O-2, CH4, H2O, and CO2 concentrations. The resemblance between the reaction kinetics on PdO/ZrO2 and on other supported PdO catalysts suggests that the mechanistic conclusions reached in this study are generally valid for methane combustion catalysts based on PdO. (C) 1999 academic Press. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. EO Lawrence Berkeley Natl Lab, Div Mat & Chem Sci, Berkeley, CA 94720 USA. RP Iglesia, E (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017; OI Iglesia, Enrique/0000-0003-4109-1001; Bell, Alexis/0000-0002-5738-4645 NR 11 TC 54 Z9 54 U1 1 U2 24 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD NOV 15 PY 1999 VL 188 IS 1 BP 132 EP 139 DI 10.1006/jcat.1999.2643 PG 8 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 256HC UT WOS:000083719000014 ER PT J AU VanderWiel, DP Pruski, M King, TS AF VanderWiel, DP Pruski, M King, TS TI A kinetic study on the adsorption and reaction of hydrogen over silica-supported ruthenium and silver-ruthenium catalysts during the hydrogenation of carbon monoxide SO JOURNAL OF CATALYSIS LA English DT Article DE Fischer-Tropsch; ruthenium; silver; bimetallic catalysts; hydrogen adsorption; carbon monoxide hydrogenation ID FISCHER-TROPSCH SYNTHESIS; NUCLEAR-MAGNETIC-RESONANCE; CU BIMETALLIC CATALYSTS; ADSORBED HYDROGEN; CO HYDROGENATION; MICROCALORIMETRIC MEASUREMENTS; HYDROCARBON SYNTHESIS; METHANATION REACTION; POLYCRYSTALLINE RU; RU/SIO2 CATALYSTS AB The simultaneous adsorption and reaction of hydrogen with preadsorbed carbon monoxide was investigated over a series of silica-supported ruthenium and silver-ruthenium bimetallic catalysts to elucidate the role of site sensitivity on hydrogen adsorption and methane formation. The specific rate of methane synthesis, which is a direct measure of the catalyst activity toward the Fischer-Tropsch synthesis, measured at 460 Torr and temperatures from 400 to 500 K, varied from 0.01 x 10(-3) to 3 x 10(-3) s(-1). As little as 3% Ag reduced the methanation rate of Ru by 80%. The temperature dependence of the turnover frequency showed that the apparent activation energy for methanation dropped from 24 kcal mol(-1) for the monometallic ruthenium case to 18 kcal mol(-1) for the bimetallic case. Since silver does not adsorb or react with either hydrogen or carbon monoxide, these results show that silver does not act merely as a dilutant in the bimetallic system. These observations are elucidated in terms of a new model for surface-sensitive hydrogen adsorption, termed "portal site mediated adsorption," where low-coordination edge and corner sites on the catalyst surface act as sinks for rapid, dissociative adsorption of weakly bound, highly mobile surface hydrogen. In situ H-1-NMR measurements of surface hydrogen coverages during reaction were used to confirm the kinetic model treatment of the reaction data. (C) 1999 Academic Press. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Kansas State Univ, Manhattan, KS 66506 USA. RP VanderWiel, DP (reprint author), Pacific NW Natl Lab, POB 999,MSIN K8-93, Richland, WA 99352 USA. NR 71 TC 35 Z9 36 U1 2 U2 18 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD NOV 15 PY 1999 VL 188 IS 1 BP 186 EP 202 DI 10.1006/jcat.1999.2646 PG 17 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 256HC UT WOS:000083719000019 ER PT J AU Rakitzis, TP Hall, GE Costen, ML Zare, RN AF Rakitzis, TP Hall, GE Costen, ML Zare, RN TI Relationship between bipolar moments and molecule-frame polarization parameters in Doppler photofragment spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ANGULAR-MOMENTUM; PHOTODISSOCIATION; FRAGMENTS; ORIENTATION; LIGHT; ICN AB In terms of the molecular-frame polarization parameters a(q)((k))(p), an equation is derived that describes the shape of a photofragment Doppler profile as a function of the three angles Gamma, Delta, and Phi that specify the photolysis and probe laser polarizations about the detection axis. This expression is specialized to linearly polarized photolysis and probe laser beams. For the particular value of the angle between the probe laser polarization and the detection axis, Delta=pi/2, this equation can be reduced to the form of well-known laboratory-frame expressions that use the bipolar moment formalism introduced by Dixon. Comparison of these forms shows the equivalence of the two formalisms and gives the relationships between the bipolar moments beta(Q)(K)(k(1)k(2)) and the molecule-frame a(q)((k))(p) parameters. We show that linear combinations of the bipolar moments completely describe photofragment polarization in the molecular frame and possess distinct quantum mechanical significance. In particular, it is shown that the coherent contribution to the photofragmentalignment is proportional to the linear combination (1/5)beta(0)(2)(02)-(1/7)beta(0)(2)(22)-(12/35)beta(0)(2)(42). (C) 1999 American Institute of Physics. [S0021-9606(99)01543-3]. C1 Fdn Res & Technol Hellas, Inst Elect Struct & Laser, Heraklion 71110, Greece. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RP Rakitzis, TP (reprint author), Fdn Res & Technol Hellas, Inst Elect Struct & Laser, Heraklion 71110, Greece. RI Zare, Richard/A-8410-2009; Rakitzis, T. Peter/C-5564-2011; Hall, Gregory/D-4883-2013; Costen, Matthew/K-5178-2012 OI Rakitzis, T. Peter/0000-0002-0385-3936; Hall, Gregory/0000-0002-8534-9783; Costen, Matthew/0000-0002-6491-9812 NR 12 TC 37 Z9 37 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 1999 VL 111 IS 19 BP 8751 EP 8754 DI 10.1063/1.480223 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400001 ER PT J AU Choi, CH Ivanic, J Gordon, MS Ruedenberg, K AF Choi, CH Ivanic, J Gordon, MS Ruedenberg, K TI Rapid and stable determination of rotation matrices between spherical harmonics by direct recursion SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article AB Recurrence relations are derived for constructing rotation matrices between complex spherical harmonics directly as polynomials of the elements of the generating 3x3 rotation matrix, bypassing the intermediary of any parameters such as Euler angles. The connection to the rotation matrices for real spherical harmonics is made explicit. The recurrence formulas furnish a simple, efficient, and numerically stable evaluation procedure for the real and complex representations of the rotation group. The advantages over the Wigner formulas are documented. The results are relevant for directing atomic orbitals as well as multipoles. (C) 1999 American Institute of Physics. [S0021- 9606(99)01341-0]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP Choi, CH (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 11 TC 81 Z9 82 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 NOV 15 PY 1999 VL 111 IS 19 BP 8825 EP 8831 DI 10.1063/1.480229 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400011 ER PT J AU Asmis, KR Taylor, TR Neumark, DM AF Asmis, KR Taylor, TR Neumark, DM TI Anion photoelectron spectroscopy of B2N- SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BORON NITROGEN CLUSTERS; SYMMETRY-BREAKING; ELECTRON-AFFINITIES; DOUBLES MODEL; BASIS-SETS; BN; ATOMS; TRANSITION; NITRIDE; SPECTRA AB Vibrationally resolved 355 and 266 nm anion photoelectron spectra of B2N are presented. Photodetachment to two electronic states of linear B-N-B is observed and, aided by electronic structure calculations, assigned to the (X) over tilde (1)Sigma(g)(+)-->(X) over tilde (2)Sigma(u)(+)+e(-) and (X) over tilde (1)Sigma(g)(+)-->(A) over tilde (2)Sigma(g)(+)+e(-) transitions. The electron affinity of B2N is 3.098 +/- 0.005 eV and the (A) over tilde (2)Sigma(g)(+) term energy T-0 is 0.785 +/- 0.005 eV. Observation of excitations involving uneven quanta of the antisymmetric stretching mode (v(3)) indicates a breakdown of the Franck-Condon (FC) approximation and results from Herzberg-Teller vibronic coupling between the (A) over tilde (2)Sigma(u)(+) and (A) over tilde (2)Sigma(g)(+) states involving the v(3) mode. Measurement of the angular dependence of the photodetached electrons serves as a sensitive probe for the identification of these FC forbidden transitions. A linear vibronic coupling model qualitatively reproduces the perturbed v(3) potentials of the (X) over tilde and (A) over tilde states. Artifactual symmetry breaking along the v(3) coordinate is observed in the ab initio wave functions for the neutral ground state up to the coupled-cluster level of theory, even when Brueckner orbitals are used. No evidence is found for an energetically low-lying cyclic state of B2N, which has been invoked in the assignment of the matrix infrared spectrum of B2N. However, the matrix infrared data agrees well with the peak spacing observed in the photoelectron spectra and reassigned to the linear (X) over tilde (2)Sigma(u)(+) ground state. (C) 1999 American Institute of Physics. [S0021-9606(99)00743-6]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Asmis, KR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM dan@radon.cchem.berkeley.edu RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 51 TC 63 Z9 63 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 1999 VL 111 IS 19 BP 8838 EP 8851 DI 10.1063/1.480230 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400013 ER PT J AU Evans, M Ng, CY AF Evans, M Ng, CY TI Rotationally resolved pulsed field ionization photoelectron study of CO+(X (2)Sigma(+),v(+)=0-42) in the energy range of 13.98-21.92 eV SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENHANCED MULTIPHOTON IONIZATION; HIGH-RESOLUTION; SYNCHROTRON-RADIATION; DIATOMIC-MOLECULES; SELECTION-RULES; CARBON-MONOXIDE; SPECTROSCOPY; THRESHOLD; CO; STATE AB We have obtained rotationally resolved pulsed field ionization-photoelectron (PFI-PE) spectra of CO in the energy range of 13.98-21.92 eV, covering the ionization transitions CO+(X (2)Sigma(+),v(+)=0-42,N+)<-- CO(X (1)Sigma(+),v"=0,N"). The PFI-PE bands for CO+ (X (2)Sigma(+), v(+)=8-22, 24, and 28-39) obtained here represent the first rotationally resolved spectroscopic data for these states. The high-resolution features observed in the PFI-PE spectra allow the identification of vibrational bands for the CO+ (X (2)Sigma(+), v(+)=10, 14, 15, 17, 18, 21, 24, 25, 29-31, 33, 35-37, and 39) states, which strongly overlap with prominent vibrational bands of the CO+(A (2)Pi(3/2,1/2),B (2)Sigma(+)) states. The simulation using the Buckingham-Orr-Sichel model has provided accurate molecular constants for CO+(X (2)Sigma(+),v(+)=0-42), including ionization energies, vibrational constants (omega(e)(+)=2218.8 +/- 3.5 cm(-1), omega(e)(+)x(e)(+)=16.20 +/- 0.32 cm(-1), omega(e)(+)y(e)(+)=0.074 +/- 0.011 cm(-1), and omega(e)(+)z(e)(+)=-0.001 83 +/- 0.000 13 cm(-1)), and rotational constants [B-e(+)=1.9797 +/- 0.0051 cm(-1), alpha(e)(+)=0.0201 +/- 0.0011 cm(-1), gamma(e)(+)=0.000 122 +/- 0.000 067 cm(-1), z(e)(+)=-(5.2 +/- 1.1)x10(-6) cm(-1)]. Enhancement of Delta N < 0 rotational branches, attributable to field-induced rotational autoionization, was clearly discernible in PFI-PE bands for CO+ (X (2)Sigma(+), v(+)=0-5, 11, and 12). Significant local enhancements due to near-resonance autoionization were observed for low v(+) (< 10) PFI-PE bands of CO+(X (2)Sigma(+)), where the density of interloper Rydberg states converging to higher ionic levels is high as manifested in the photoion spectrum. The observation of a long vibrational progression in the Franck-Condon gap region, where strong autoionization states are absent, is consistent with the suggestion that high-n Rydberg states converging to highly excited vibrational levels of CO+(X (2)Sigma(+)) are partially populated via direct excitation to a repulsive neutral state. The relatively minor band intensity variation observed for high v(+) PFI-PE bands is also in accord with the direct excitation model. Since Delta N=0, +/- 1, +/- 2, and +/- 3 rotational branches are observed in the PFI-PE spectra, we conclude that the ejected photoelectrons are restricted to angular momentum continuum states l=0-4. (C) 1999 American Institute of Physics. [S0021-9606(99)00643-1]. C1 Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Ng, CY (reprint author), Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. NR 56 TC 32 Z9 33 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 1999 VL 111 IS 19 BP 8879 EP 8892 DI 10.1063/1.480259 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400018 ER PT J AU Hirata, S Lee, TJ Head-Gordon, M AF Hirata, S Lee, TJ Head-Gordon, M TI Time-dependent density functional study on the electronic excitation energies of polycyclic aromatic hydrocarbon radical cations of naphthalene, anthracene, pyrene, and perylene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIFFUSE INTERSTELLAR BANDS; VIBRONIC ABSORPTION-SPECTRA; MATRIX-ISOLATED NAPHTHALENE; SOLID ARGON; VIBRATIONAL-SPECTRA; INFRARED-SPECTRUM; RESPONSE THEORY; SPECTROSCOPY; IONIZATION; APPROXIMATION AB Time-dependent density functional theory (TDDFT) and its modification, the Tamm-Dancoff approximation to TDDFT, are employed to calculate the electronic excitation energies and oscillator strengths for a series of polycyclic aromatic hydrocarbon radical cations. For the radical cations of naphthalene and anthracene, TDDFT using the Becke-Lee-Yang-Parr functional and the 6-31G** basis set provides the excitation energies that are roughly within 0.3 eV of the experimental data. The assignments of the electron transitions proposed by TDDFT accord with the previous assignments made by accurate ab initio calculations, except that TDDFT indicates the existence of a few additional transitions of pi*<--sigma character among the several low-lying transitions. The calculated energies for these pi*<--sigma transitions are found to be consistent with the onset of a sigma electron ionization manifold in the photoelectron spectra. For the pyrene radical cation, TDDFT supports the previous assignments made by semiempirical calculations, whereas for the perylene radical cation, TDDFT suggests the energy ordering of the three lowest-lying excited states be changed from those of the semiempirical results. (C) 1999 American Institute of Physics. [S0021-9606(99)30542-0]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Head-Gordon, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Lee, Timothy/K-2838-2012 NR 54 TC 186 Z9 187 U1 6 U2 61 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 NOV 15 PY 1999 VL 111 IS 19 BP 8904 EP 8912 DI 10.1063/1.480235 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400020 ER PT J AU Larsen, DS Ohta, K Fleming, GR AF Larsen, DS Ohta, K Fleming, GR TI Three pulse photon echo studies of nondipolar solvation: Comparison with a viscoelastic model SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATIONAL POPULATION RELAXATION; SAPPHIRE REGENERATIVE AMPLIFIER; MOLECULAR-DYNAMICS SIMULATION; SHORT-TIME DYNAMICS; NONPOLAR SOLVATION; POLAR SOLVATION; ULTRAFAST SOLVATION; DIPOLAR LIQUIDS; RHODOBACTER-SPHAEROIDES; DIELECTRIC FRICTION AB Three pulse stimulated photon echo peak shift (3PEPS) measurements were used to probe the solvation of a quadrupolar solute in three room temperature nondipolar solvents; benzene, CCl4, and CS2, and the results were compared with those for two polar solvents, methanol and acetonitrile, and one weakly polar solvent, toluene. Our data reveal three distinct solvent dynamical time scales; a sub-100 fs ultrafast component attributed to inertial motions, a slow (similar to 2-3 ps) component attributed to structural relaxation, and an intermediate time scale (similar to 600 fs) of uncertain origin. The six solvents were chosen to reflect a range of possible interactions, but exhibit similar dynamics, suggesting that similar mechanisms may be at work or that different mechanisms may exist, but occur on similar time scales. A viscoelastic continuum solvation model proposed to describe nonpolar solvation [J. Phys. Chem. A 102, 17 (1998)] was used for a preliminary analysis of our data. (C) 1999 American Institute of Physics. [S0021-9606(99)50643-0]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Larsen, DS (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 76 TC 83 Z9 83 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 1999 VL 111 IS 19 BP 8970 EP 8979 DI 10.1063/1.480240 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400027 ER PT J AU Curro, JG Webb, EB Grest, GS Weinhold, JD Putz, M McCoy, JD AF Curro, JG Webb, EB Grest, GS Weinhold, JD Putz, M McCoy, JD TI Comparisons between integral equation theory and molecular dynamics simulations for realistic models of polyethylene liquids SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MONTE-CARLO SIMULATIONS; INTERACTION SITE MODEL; SATURATED-HYDROCARBON POLYMERS; PAIR CORRELATION-FUNCTIONS; LOCAL-STRUCTURE; INTERMOLECULAR POTENTIALS; CLOSURE APPROXIMATIONS; EQUILIBRIUM-THEORY; PHASE-EQUILIBRIA; MIXING BEHAVIOR AB Molecular dynamics (MD) simulations were performed on dense liquids of polyethylene chains of 24 and 66 united atom CH2 units. A series of models was studied ranging in atomistic detail from coarse-grained, freely-jointed, tangent site chains to realistic, overlapping site models subjected to bond angle restrictions and torsional potentials. These same models were also treated with the self-consistent, polymer reference interaction site model (PRISM) theory. The intramolecular and total structure factors, as well as, the intermolecular radial distribution functions g(r) and direct correlation functions C(r) were obtained from theory and simulation. Angular correlation functions were also obtained from the MD simulations. Comparisons between theory and simulation reveal that PRISM theory works well for computing the intermolecular structure of coarse-grained chain models, but systematically underpredicts the extent of intermolecular packing, and overpredicts the compressibility, as more realistic details are introduced into the model. We found that the PRISM theory could be considerably improved by adding a tail function to C(r) beyond the effective hard core diameter. The range of this tail function was determined by requiring the theory to yield the correct compressibility. The intermolecular radial distribution functions from this modified PRISM theory were in excellent agreement with g(r)'s obtained from the simulations. (C) 1999 American Institute of Physics. [S0021-9606(99)50843-X]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Ctr Microengineered Mat, Albuquerque, NM 87106 USA. New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87185 USA. RP Curro, JG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI McCoy, John/B-3846-2010 OI McCoy, John/0000-0001-5404-1404 NR 61 TC 25 Z9 25 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 1999 VL 111 IS 19 BP 9073 EP 9081 DI 10.1063/1.480335 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 251GQ UT WOS:000083437400038 ER PT J AU Denn, MM Marrucci, G AF Denn, MM Marrucci, G TI Squeeze flow between finite plates SO JOURNAL OF NON-NEWTONIAN FLUID MECHANICS LA English DT Article DE squeeze flow; infinite/finite plates AB The general solution for squeeze flow between closely-spaced plates of arbitrary shape includes an in-plane potential how whose components satisfy the Cauchy-Riemann conditions, and the velocity held and the pressure are both determined by the boundary conditions at the edge of the plates. In contrast, the velocity field for the infinite-plate limit only requires boundary conditions at the surfaces of the plates. The infinite-plate problem is singular, and makes sense only as a limit of a sequence of hows in finite geometries, each of which has a well-defined coordinate origin. (C)1999 Elsevier Science B.V. All rights reserved. C1 CUNY City Coll, Levich Inst, New York, NY 10031 USA. Univ Naples, Dipartimento Ingn Chim, I-80125 Naples, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Denn, MM (reprint author), CUNY City Coll, Levich Inst, 1 M Steinman Hall,140th St & Convent Ave, New York, NY 10031 USA. NR 6 TC 8 Z9 8 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0257 J9 J NON-NEWTON FLUID JI J. Non-Newton. Fluid Mech. PD NOV 15 PY 1999 VL 87 IS 2-3 BP 175 EP 178 DI 10.1016/S0377-0257(99)00062-2 PG 4 WC Mechanics SC Mechanics GA 254XW UT WOS:000083640400007 ER PT J AU Nguyen, D Kim, JS Guiver, MD Eisenberg, A AF Nguyen, D Kim, JS Guiver, MD Eisenberg, A TI Clustering in carboxylated polysulfone ionomers: A characterization by dynamic mechanical and small-angle X-ray scattering methods SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE dynamic mechanical; small-angle X-ray scattering; ionomers; carboxylated polysulfone ID VISCOELASTIC PROPERTIES; SULFONATED POLYSULFONE AB The dynamic mechanical properties and morphology of carboxylated polysulfone ionomers were investigated by dynamic mechanical thermal analysis and small-angle X-ray scattering (SAXS) techniques. It was found that at 25 mol % of ions, ionomers show two glass transitions: one at about 200 degrees C (the matrix T-g) and the other at about 235 degrees C (the cluster T-g). It was also found that with increasing ion content up to about 37 mol %, the matrix T-g shifted to higher temperatures and the size of tan delta peak decreased. The cluster T-g did not change. From the results, it is suggested that even at high ion content, the ionomers contain a significant amount of unclustered material, but that the increase in the ion content does not increase the amount of clustered material. SAXS profiles showed the ionic peak, which represents the presence of multiplets in the cluster regions. In addition, the difference in the matrix and cluster T-g's of this ionomer system was found to be about 35 degrees. Thus, it is postulated that ionic group aggregation is subject to steric hindrance owing to the bulkiness of benzene ring, and tension on polymer chains surrounding the multiplet owing to chain rigidity, which limit the size and stability of the multiplet significantly. (C) 1999 John Wiley & Sons, Inc. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Chosun Univ, Dept Polymer Sci & Engn, Kwangju 501600, South Korea. Natl Res Council Canada, Inst Chem Proc & Environm Technol, Ottawa, ON K1A 0R6, Canada. McGill Univ, Dept Chem, Montreal, PQ H3A 2K6, Canada. RP Nguyen, D (reprint author), Brookhaven Natl Lab, Dept Phys, Bldg 750, Upton, NY 11973 USA. RI Eisenberg, Adi/B-8676-2008; Guiver, Michael/I-3248-2016 OI Guiver, Michael/0000-0003-2619-6809 NR 20 TC 10 Z9 10 U1 2 U2 10 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 NOV 15 PY 1999 VL 37 IS 22 BP 3226 EP 3232 DI 10.1002/(SICI)1099-0488(19991115)37:22<3226::AID-POLB7>3.0.CO;2-M PG 7 WC Polymer Science SC Polymer Science GA 252FN UT WOS:000083491600007 ER PT J AU Stock, JM Lewis, CJ Nagy, EA AF Stock, JM Lewis, CJ Nagy, EA TI The Tuff of San Felipe: an extensive middle Miocene pyroclastic flow deposit in Baja California, Mexico SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Gulf of California; Baja California; Mexico; ignimbrite; Ar-40/Ar-39 ID VOLCANISM; PROVINCE; RECORD; NEVADA; FERMIN; GULF; AREA AB We document the existence of a widespread Miocene ash-flow tuff sheet in northeastern Baja California, Mexico. The Tuff of San Felipe (new name) was erupted from a vent east of the Sierra San Felipe of NE Baja California at ca. 12.6 Ma. This is the only widespread middle Miocene pyroclastic flow deposit identified in northeastern Baja California. Its distinctive age and widespread distribution make it an important marker horizon for structural reconstruction of this part of the Gulf Extensional Province, which is on the Pacific plate. The vent position, near the modern Gulf of California coast, allows the possibility that exposures of the Tuff of San Felipe may be preserved, east of the Gulf on the North America plate in Sonora, yielding a tie point for the past relative position of the two plates. This paper summarizes all known information including petrography, geochemistry, geochronology, paleomagnetics, geographic distribution, and field appearance of this important tuff. It is a densely welded, crystal-rich, lithic-lapilli pyroclastic Mow deposit, with 5-15% alkali feldspar, and can be 180 m thick in some locations near the vent. The Tuff of San Felipe is >40 m thick up to 40 km SW of the vent and >10 m thick at least 25 km NNW of the vent. A minimum volume estimate for the deposit is 54 km(3). Some recent Ar-40/Ar-39 age determinations suggest that the tuff is about 12.6 Ma in age. In all locations studied, the Tuff of San Felipe has a unique, low-inclination, reversed magnetization, which may record a field transition or a geomagnetic excursion within reversed polarity subchron C5Ar.2r (12.401 to 12.678 Ma). This low-inclination magnetization, as well as the mineralogy and age, is key to correlating the tuff across the region, because deposits are highly disrupted by subsequent normal faulting and outcrops are sparse and discontinuous away from the vent. The documentation of these characteristics is important because the Tuff of San Felipe is a key structural marker for the subsequent development of the Pacific-North America plate boundary in the Gulf of California, and it will be important to identify this tuff in outcrops elsewhere on the Baja California Peninsula and on the North America plate in Sonora. (C) 1999 Elsevier Science B.V. All rights reserved. C1 CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Stock, JM (reprint author), CALTECH, 252-21, Pasadena, CA 91125 USA. OI Stock, Joann Miriam/0000-0003-4816-7865 NR 41 TC 26 Z9 27 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD NOV 15 PY 1999 VL 93 IS 1-2 BP 53 EP 74 DI 10.1016/S0377-0273(99)00079-7 PG 22 WC Geosciences, Multidisciplinary SC Geology GA 267TF UT WOS:000084374800004 ER PT J AU Burton, H AF Burton, H TI The woman who knew too much: Alice Stewart and the secrets of radiation. SO LIBRARY JOURNAL LA English DT Book Review C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Burton, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD NOV 15 PY 1999 VL 124 IS 19 BP 95 EP 95 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 256ZG UT WOS:000083755900246 ER PT J AU Stahl, K Hanson, JC AF Stahl, K Hanson, JC TI Multiple cation sites in dehydrated brewsterite. An in-situ X-ray synchrotron powder diffraction study SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article DE brewsterite; in-situ powder diffraction; X-ray synchrotron radiation; zeolite dehydration AB The dehydration process of the zeolite brewsterite, Sr0.67Ba0.33Al2Si6O16.5H(2)O, has been studied in situ by X-ray synchrotron radiation powder diffraction. Sixty-one consecutive powder patterns were collected between 310 and 684 K, in steps of 6 K, at 5 min intervals, and the crystal structures were refined using the Rietveld method. At 310 K, the original cation and four water sites are fully occupied. As water is expelled, three alternative cation sites successively appear. These cation sites generally have more framework oxygens in their coordination spheres, and/or show an increasing ability to share water molecules between themselves. Most aspects of the brewsterite dehydration process can be related to the variations in the cation site occupancies. The total water content during the dehydration can be fully modelled, based on the occupancies of two of the cation sites. Also, the maxima in the dehydration rate and the reduction in unit cell volume are strongly correlated to cation site occupancies. The connection between the tetrahedral sheets building the brewsterite framework, the T4-O9-T4 angle, is reduced by 25 degrees between 550 and 610 K. The strain at this 'weak link' is believed to be the direct cause of the destruction of crystallinity, whereas the clustering of cations inherent to an effective water sharing is considered as the cause of this framework strain. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Tech Univ Denmark, Dept Chem, DK-2800 Lyngby, Denmark. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Stahl, K (reprint author), Tech Univ Denmark, Dept Chem, Bldg 207, DK-2800 Lyngby, Denmark. RI Hanson, jonathan/E-3517-2010; OI Stahl, Kenny/0000-0002-4459-3026 NR 10 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD NOV 15 PY 1999 VL 32 IS 1-2 BP 147 EP 158 DI 10.1016/S1387-1811(99)00100-6 PG 12 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 252JW UT WOS:000083499200015 ER PT J AU Reeves, SR Pekot, LJ Koperna, GJ Ammer, JR AF Reeves, SR Pekot, LJ Koperna, GJ Ammer, JR TI Gas storage deliverability - 1 - Novel fracturing enhances deliverability SO OIL & GAS JOURNAL LA English DT Article C1 Adv Resources Int Inc, Houston, TX USA. Adv Resources Int Inc, Arlington, VA USA. US DOE, Morgantown, WV USA. RP Reeves, SR (reprint author), Adv Resources Int Inc, Houston, TX USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 USA SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD NOV 15 PY 1999 VL 97 IS 46 BP 43 EP + PG 5 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 259NV UT WOS:000083900700019 ER PT J AU Orgassa, D Fujiwara, H Schulthess, TC Butler, WH AF Orgassa, D Fujiwara, H Schulthess, TC Butler, WH TI First-principles calculation of the effect of atomic disorder on the electronic structure of the half-metallic ferromagnet NiMnSb SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-PROPERTIES; HEUSLER COMPOUNDS; PTMNSB; MAGNETORESISTANCE; TRANSPORT; FILMS AB The electronic structure of the half-metallic ferromagnet NiMnSb with three different types of atomic disorder is calculated using the layer Korringa-Kohn-Rostoker method in conjunction with the coherent potential approximation. Results indicate the presence of minority-spin states at the Fermi energy for degrees of disorder as low as a few percent. The resulting spin polarization below 100% is discussed in the light of experimental difficulties confirming the half-metallic property of NiMnSb thin films directly. [S0163-1829(99)04743-8]. C1 Univ Alabama, Ctr Mat Informat Technol, MINT, Tuscaloosa, AL 35487 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Orgassa, D (reprint author), Univ Alabama, Ctr Mat Informat Technol, MINT, Tuscaloosa, AL 35487 USA. EM dorgassa@mint.ua.edu NR 21 TC 179 Z9 179 U1 2 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 NOV 15 PY 1999 VL 60 IS 19 BP 13237 EP 13240 DI 10.1103/PhysRevB.60.13237 PG 4 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400001 ER PT J AU Kang, JS Olson, CG Jung, JH Lee, ST Noh, TW Min, BI AF Kang, JS Olson, CG Jung, JH Lee, ST Noh, TW Min, BI TI Temperature-dependent resonant photoemission study of the metallic and charge-ordered phases of Pr1-xSrxMnO3 SO PHYSICAL REVIEW B LA English DT Article ID COLOSSAL-MAGNETORESISTANCE MANGANITES; ELECTRONIC-STRUCTURE; MANGANESE OXIDES; LATTICE-DYNAMICS; LA1-XSRXMNO3; LA1-XCAXMNO3; SPECTRA; PEROVSKITES; TRANSPORT; FILMS AB A resonant photoemission study has been performed for Pr1-xSrxMnO3 (x = 1/3,1/2) and the partial spectral weight (PSW) distributions of both Pr 4f and Mn 3d electrons have been determined. With varying temperature (T) and x, metal-insulator transitions are observed in the photoemission data. The Pr ions in Pr1-xSrxMnO3 are trivalent, and Pr 4f PSW exhibits a dominant hybridization peak indicating large Pr 4f-O 2p mixing. The Mn 3d PSW at low T shows a charge gap for x = 1/2, and a reduced spectral intensity near E-F for x = 1/3, suggesting the localized nature due to the lattice polaron formation. [S0163-1829(99)00944-3]. C1 Catholic Univ Korea, Dept Phys, Puchon 422743, South Korea. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Seoul Natl Univ, Ctr Strongly Correlated Mat Res, Seoul 151742, South Korea. Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea. RP Kang, JS (reprint author), Catholic Univ Korea, Dept Phys, Puchon 422743, South Korea. RI Jung, Jong Hoon/G-8426-2011; Noh, Tae Won /K-9405-2013 NR 33 TC 17 Z9 18 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 NOV 15 PY 1999 VL 60 IS 19 BP 13257 EP 13260 DI 10.1103/PhysRevB.60.13257 PG 4 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400006 ER PT J AU Myers, KD Bud'ko, SL Antropov, VP Harmon, BN Canfield, PC Lacerda, AH AF Myers, KD Bud'ko, SL Antropov, VP Harmon, BN Canfield, PC Lacerda, AH TI de Haas-van Alphen and Shubnikov-de Haas oscillations in RAgSb2 (R = Y, La-Nd, Sm) SO PHYSICAL REVIEW B LA English DT Article AB de Haas-van Alphen and Shubnikov-de Haas oscillations have been used to study the Fermi surface of the simple tetragonal RAgSb2 series of compounds with R = Y, La-Nd, and Sm. The high quality of the flux-grown single crystals, coupled with very small extremal cross sections of Fermi surface, allow the observation of quantum oscillations at modest fields (H<30 kG) and high temperatures (up to 25 K in SmAgSb2). For H parallel to c, the effective masses, determined from the temperature dependence of the amplitudes, are quite small, typically between 0.07 and 0.5m(0). The topology of the Fermi surface was determined from the angular dependence of the frequencies for R = Y, La, and Sm. In SmAgSb2, antiferromagnetic ordering below 8.8 K is shown to dramatically alter the Fermi surface. For LaAgSb2 and CeAgSb2, the effect of applied hydrostatic pressure on the frequencies was also studied. Finally, the experimental data were compared to the Fermi surface calculated within the tight-binding linear muffin-tin orbital approximation. Overall, the calculated electronic structure was found to be consistent with the experimental data. [S0163-1829(99)09443-6]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Alamos Natl Lab, Los Alamos Facil, Natl High Field Lab, Los Alamos, NM 87545 USA. RP Myers, KD (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 17 TC 25 Z9 25 U1 3 U2 20 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 NOV 15 PY 1999 VL 60 IS 19 BP 13371 EP 13379 DI 10.1103/PhysRevB.60.13371 PG 9 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400034 ER PT J AU Pagliuso, PG Rettori, C Sarrao, JL Cornelius, A Hundley, MF Fisk, Z Oseroff, SB AF Pagliuso, PG Rettori, C Sarrao, JL Cornelius, A Hundley, MF Fisk, Z Oseroff, SB TI Electron spin resonance of Gd3+ and Nd3+ in LuInA(4) (A = Cu,Ni) SO PHYSICAL REVIEW B LA English DT Article ID COMPOUND; YBINCU4; ESR; LUINCU4; METALS AB Low-temperature (1.6 K less than or similar to T less than or similar to 60 K) data of electron spin resonance for Gd3+ and Nd3+ diluted in LuInA(4) (A = Cu, Ni) compounds are presented. The results are interpreted in terms of a density of states: at the Fermi level built up of a single s band for the Cu-based system and a multiple (s and d) bands for the Ni-based system. The susceptibility and specific heat data show negligible electron-electron exchange enhancement for both compounds. For the Cu-based system the exchange interaction between the rare-earth (Gd3+ and Nd3+) local moment and the conduction electrons depends on the conduction-electron wave vector. [S0163-1829(99)02939-2]. C1 UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. San Diego State Univ, San Diego, CA 92182 USA. RP Pagliuso, PG (reprint author), UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. RI Cornelius, Andrew/A-9837-2008; Rettori, Carlos/C-3966-2012; Pagliuso, Pascoal/C-9169-2012; Inst. of Physics, Gleb Wataghin/A-9780-2017 OI Rettori, Carlos/0000-0001-6692-7915; NR 28 TC 11 Z9 11 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 1999 VL 60 IS 19 BP 13515 EP 13519 DI 10.1103/PhysRevB.60.13515 PG 5 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400051 ER PT J AU Laaziri, K Kycia, S Roorda, S Chicoine, M Robertson, JL Wang, J Moss, SC AF Laaziri, K Kycia, S Roorda, S Chicoine, M Robertson, JL Wang, J Moss, SC TI High-energy x-ray diffraction study of pure amorphous silicon SO PHYSICAL REVIEW B LA English DT Article ID STRUCTURAL RELAXATION; NEUTRON-DIFFRACTION; MOLECULAR-DYNAMICS; HYDROGEN; SCATTERING; SI; GENERATION; ELECTRONS; DENSITY; ATOMS AB Medium and high-energy x-ray diffraction has been used to study the atomic structure of pure amorphous Si prepared by MeV Si implantation into crystalline silicon. Both as-implanted and annealed samples were studied. The inelastically scattered x rays were removed by fitting the energy spectrum for the scattered x rays. The atomic scattering factor of silicon, previously known reliably up to 20 Angstrom(-1), has been extended to 55 Angstrom(-1). The radial distribution function of amorphous Si, before and after annealing, has been determined through an unbiased Fourier transformation of the normalized scattering data. Gaussian fits to the first neighbor peak in these functions shows that scattering data out to at least 40 Angstrom(-1) is required to reliably determine the radial distribution function. The first-shell coordination number increases from 3.79 to 3.88 upon thermal annealing at 600 degrees C, whereas that of crystalline Si determined from similar measurements on a Si powder analyzed using the same technique is 4.0. Amorphous Si is therefore under coordinated relative to crystalline Si. Noise in the distribution function, caused by statistical. variations in the scattering data at high-momentum transfer, has been reduced without affecting the experimental resolution through filtering of the interference function after subtracting the contribution of the first-neighbor peak. The difference induced by thermal annealing in the remainder of the radial distribution functions, thus revealed, is much smaller than previously believed. [S0163-1829(99)00943-1]. C1 Univ Montreal, Dept Phys, Grp Rech Phys & Technol Couches Minces, Montreal, PQ H3C 3J7, Canada. Cornell Univ, Wilson Lab, CHESS, Ithaca, NY 14853 USA. Oak Ridge Natl Lab, Div Solid State, Neutron Scattering Grp, Oak Ridge, TN 37831 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. RP Laaziri, K (reprint author), Univ Montreal, Dept Phys, Grp Rech Phys & Technol Couches Minces, CP 6128,Succursale Ctr Ville, Montreal, PQ H3C 3J7, Canada. EM Sjoerd.Roorda@umontreal.ca RI Roorda, Sjoerd/N-2604-2014 NR 53 TC 139 Z9 139 U1 3 U2 31 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 NOV 15 PY 1999 VL 60 IS 19 BP 13520 EP 13533 DI 10.1103/PhysRevB.60.13520 PG 14 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400052 ER PT J AU Soo, YL Huang, S Kao, YH Chen, JG Hulbert, SL Geisz, JF Kurtz, S Olson, JM Kurtz, SR Jones, ED Allerman, AA AF Soo, YL Huang, S Kao, YH Chen, JG Hulbert, SL Geisz, JF Kurtz, S Olson, JM Kurtz, SR Jones, ED Allerman, AA TI Local structures and interface morphology of InxGa1-xAs1-yNy thin films grown on GaAs SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-ABSORPTION; FINE-STRUCTURE; EDGE; PERFORMANCE; GAINNAS AB X-ray absorption fine-structure techniques have been utilized to probe the short-range structures around N and In in InxGa1-xAs1-yNy compounds containing about 3% of N and 8% of In. Our results indicate that N impurities!; most likely substitute for As atoms in the system. The In-As interatomic distance in these compounds remains practically the same as in InAs, while the coordination number of As atoms around In shows possible variations with changes in the material characteristics. The N atoms play an important role in affecting the changes of band gap while also serving as "strain moderators" by providing a tensile strain in the film to counteract the compressive strain caused by the In impurities. Further, grazing incidence x-ray scattering measurements of InxGa1-xAs1-yNy/GaAs heterojunctions provide direct evidence that the InxGa1-xAs1-yNy thin films can indeed be lattice matched to GaAs substrates resulting in a reasonably smooth heterointerface. [S0163-1829(99)11643-6]. C1 SUNY Buffalo, Dept Phys, Amherst, NY 14260 USA. Univ Delaware, Dept Mat Sci & Engn, Newark, DE 19716 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Soo, YL (reprint author), SUNY Buffalo, Dept Phys, Amherst, NY 14260 USA. NR 17 TC 15 Z9 16 U1 3 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 NOV 15 PY 1999 VL 60 IS 19 BP 13605 EP 13611 DI 10.1103/PhysRevB.60.13605 PG 7 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400061 ER PT J AU Lee, TL Pillai, MR Woicik, JC Labanda, G Lyman, PF Barnett, SA Bedzyk, MJ AF Lee, TL Pillai, MR Woicik, JC Labanda, G Lyman, PF Barnett, SA Bedzyk, MJ TI Atomic-resolution study of lattice distortions of buried InxGa1-xAs monolayers in GaAs(001) SO PHYSICAL REVIEW B LA English DT Article ID STRAINED-SEMICONDUCTOR ALLOYS; ABSORPTION FINE-STRUCTURE; RAY STANDING WAVES; HETEROSTRUCTURES; FILMS; DIFFRACTION; GA1-XINXAS; INAS AB X-ray standing wave measurements were used to study the strain in one monolayer of pseudobinary alloy InxGa1-xAs buried in GaAs(001) by molecular-beam epitaxy. The measured In position along the [001] direction exhibited a nearly linear dependence on the In concentration I, thus supporting the validity of macroscopic continuum elasticity theory at the one-monolayer limit. A random-cluster calculation using a valence force field was performed to explain microscopically the origin of the vertical expansion of the strained monolayer observed by the experiment. The calculated As-In-As bond angle and the positions of the first-nearest-neighbour As atoms of In suggest that the nearly linear dependence of the In height on the alloy composition is a combined result of the As-In-As bond bending and the local lattice distortion at the GaAs/InyGa1-yAs interface. The calculated In-As and Ca-As bond lengths were found to depend weakly on the In concentration, consistent with an earlier calculation for the case of a thick InxGa1-xAs film on GaAs(001) and the available x-ray absorption fine-structure data. [S0163-1829(99)05143-7]. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Northwestern Univ, Mat Res Ctr, Evanston, IL 60208 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Lee, TL (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Bedzyk, Michael/B-7503-2009; Barnett, Scott/B-7502-2009; Bedzyk, Michael/K-6903-2013 NR 31 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 NOV 15 PY 1999 VL 60 IS 19 BP 13612 EP 13618 DI 10.1103/PhysRevB.60.13612 PG 7 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400062 ER PT J AU Twesten, RD Follstaedt, DM Lee, SR Jones, ED Reno, JL Millunchick, JM Norman, AG Ahrenkiel, SP Mascarenhas, A AF Twesten, RD Follstaedt, DM Lee, SR Jones, ED Reno, JL Millunchick, JM Norman, AG Ahrenkiel, SP Mascarenhas, A TI Characterizing composition modulations in InAs/AlAs short-period superlattices SO PHYSICAL REVIEW B LA English DT Article ID LATERAL COMPOSITION MODULATION; MOLECULAR-BEAM-EPITAXY; TRANSMISSION-ELECTRON-MICROSCOPY; LAYER ORDERING PROCESS; III-V-ALLOYS; SURFACE SEGREGATION; GROWTH; GE; CONTRAST; INALAS AB The formation of quantum wires has much interest due to their novel electronic properties which may lead to enhanced optoelectronic device performance and greater photovoltaic efficiencies. One method of forming these structures is through spontaneous lateral modulation found during the epitaxial growth of III/V alloys. In this paper, we report and summarize our investigations on the formation of lateral modulation in the molecular-beam epitaxy grown InAlAs/InP(001) system. This system was grown as a short-period superlattice where n monolayers of InAs are deposited followed by m monolayers of AlAs (with n and m similar to 2) and this sequence is repeated to grow a low strain InAlAs ternary alloy on InP(001) that exhibits lateral modulation. Films were grown under a variety of conditions (growth temperature, effective alloy composition, superlattice period, and growth rate). These films have been extensively analyzed using x-ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM) and microcharacterization, in addition to photon-based spectroscopes. Here we present results of several microstructural characterizations using a wide range of TEM-based techniques, and compare them to results from the other methods to obtain a unified understanding of composition modulation. Two strong points consistently emerge:(1) The lateral modulation wavelength is insensitive to growth temperature and effective alloy composition, but the strength of the lateral modulation is greatest near an effective alloy composition of In0.46Al0.54As, which corresponds to a slightly tensile global strain with respect to InP. (2) The composition variation for the strongly modulated films is as much as 0.38 InAs mole fraction. in addition, for these strongly modulated films, the modulation wave is asymmetric showing strongly peaked, narrower InAs-rich regions separated by flat AlAs-rich regions. We discuss these results and their possible implications in addition to detailing the techniques used to obtain them. [S0163-1829(99)10743-4]. C1 Univ Illinois, Ctr Microanal Mat, Urbana, IL 61801 USA. Sandia Natl Labs, Phys & Chem Sci Ctr, Albuquerque, NM 87185 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Univ Illinois, Ctr Microanal Mat, Urbana, IL 61801 USA. RI Norman, Andrew/F-1859-2010 OI Norman, Andrew/0000-0001-6368-521X NR 46 TC 39 Z9 39 U1 0 U2 6 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 NOV 15 PY 1999 VL 60 IS 19 BP 13619 EP 13635 DI 10.1103/PhysRevB.60.13619 PG 17 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400063 ER PT J AU Klimov, VI McBranch, DW Leatherdale, CA Bawendi, MG AF Klimov, VI McBranch, DW Leatherdale, CA Bawendi, MG TI Electron and hole relaxation pathways in semiconductor quantum dots SO PHYSICAL REVIEW B LA English DT Article ID OPTICAL-PROPERTIES; ENERGY-RELAXATION; DOPED GLASSES; LUMINESCENCE PROPERTIES; CARRIER RELAXATION; CHARGE SEPARATION; CDSE NANOCRYSTALS; DYNAMICS; CONFINEMENT; ABSORPTION AB Femtosecond (fs) broad-band transient absorption (TA) is used to study the intraband relaxation and depopulation dynamics of electron and hole quantized states in CdSe nanocrystals (NC's) with a range of surface properties. Instead of the drastic reduction in the energy relaxation rate expected due to a "phonon bottleneck," we observe a fast subpicosecond 1P-to-1S electron relaxation, with the rate exceeding that due to phonon emission in bulk semiconductors. The energy relaxation is enhanced with reducing the NC's radius, and does not show any dependence on the NC surface properties (quality of the surface passivation). These data indicate that electron energy relaxation occurs by neither multiphonon emission nor by coupling to surface defects, but is likely meditated by Auger-type electron-hole energy transfer. We use fs infrared TA to probe electron and hole intraband transitions, which allows us to distinguish between electron and hole relaxation pathways leading to the depopulation of NC quantized states. In contrast to the electron relaxation, which is controlled by NC surface passivation, the depopulation of hole quantized states is extremely fast (sub-ps-to-ps time scales) in all types of samples, independent of NC surface treatment (including NC's overcoated with a ZnS layer). Our results indicate that ultrafast hole dynamics are not due to trapping at localized surface defects such as a vacancy, but rather arise from relaxation into intrinsic NC states or intrinsically unpassivated interface slates. [S0163-1829(99)02843-X]. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. MIT, Dept Chem, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RP Klimov, VI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-6,MS-J585, Los Alamos, NM 87545 USA. EM klimov@lanl.gov NR 50 TC 370 Z9 374 U1 23 U2 186 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 NOV 15 PY 1999 VL 60 IS 19 BP 13740 EP 13749 DI 10.1103/PhysRevB.60.13740 PG 10 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400075 ER PT J AU Mendoza, CI Barrera, RG Fuchs, R AF Mendoza, CI Barrera, RG Fuchs, R TI Electron energy loss in ordered arrays of polarizable spheres SO PHYSICAL REVIEW B LA English DT Article ID COMPOSITE MEDIA; LOSS SPECTRA; SYSTEMS AB We develop a theory for the energy loss of swift electrons traveling parallel to an ordered array of polarizable spheres. The energy loss is given in terms of a surface response function which is expressed as a spectral representation. The poles and weights in this representation are determined through the eigenvalues and eigenvectors of an interaction matrix. This matrix takes account of the quasistatic electromagnetic interaction between the polarized spheres to an arbitrary multipolar order. We use our theory to calculate the energy-loss spectra for cubic arrays of aluminum spheres with various numbers of layers and compare the results with those obtained using a dielectric continuum model. [S0163-1829(99)05843-9]. C1 Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Mendoza, CI (reprint author), Univ Nacl Autonoma Mexico, Inst Fis, Apartado Postal 20364, Mexico City 01000, DF, Mexico. NR 26 TC 2 Z9 2 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 1999 VL 60 IS 19 BP 13831 EP 13845 DI 10.1103/PhysRevB.60.13831 PG 15 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400086 ER PT J AU Miyamoto, Y Rubio, A Louie, SG Cohen, ML AF Miyamoto, Y Rubio, A Louie, SG Cohen, ML TI Self-inductance of chiral conducting nanotubes SO PHYSICAL REVIEW B LA English DT Article ID BORON-NITRIDE NANOTUBES; INDIVIDUAL CARBON NANOTUBES; ELECTRONIC-PROPERTIES; SINGLE-WALL; MICROTUBULES; TRANSPORT; TUBULES; ROPES AB Chiral conductivity in nanotubes has recently been predicted theoretically. The realization and application of chiral conducting nanotubes can be of great interest from both fundamental and technological viewpoints. These chiral currents, if they are realized, can be detected by measuring the self-inductance. We have treated Maxwell's equations for chiral conducting nanotubes (nanocoils) and find that the self-inductance and the resistivity of nanocoils should depend on the frequency of the alternating current even when the capacitance of the nanocoils is not taken into account. This is in contrast to elementary treatment of ordinary coils. This fact is useful to distinguish nanocoils by electrical measurements. [S0163-1829(99)00843-7]. C1 NEC Corp Ltd, Fundamental Res Labs, Tsukuba, Ibaraki 3058501, Japan. Univ Valladolid, Dept Fis Teor, E-47011 Valladolid, Spain. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Miyamoto, Y (reprint author), NEC Corp Ltd, Fundamental Res Labs, 34 Miyukigaoka, Tsukuba, Ibaraki 3058501, Japan. RI Rubio, Angel/A-5507-2008; OI Rubio, Angel/0000-0003-2060-3151; Miyamoto, Yoshiyuki/0000-0001-6834-0499 NR 30 TC 20 Z9 20 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 NOV 15 PY 1999 VL 60 IS 19 BP 13885 EP 13889 DI 10.1103/PhysRevB.60.13885 PG 5 WC Physics, Condensed Matter SC Physics GA 260GD UT WOS:000083940400093 ER PT J AU Delin, A Eriksson, O Johansson, B Auluck, S Wills, JM AF Delin, A Eriksson, O Johansson, B Auluck, S Wills, JM TI Calculated magneto-optical properties of cubic and tetragonal Fe, Co, and Ni SO PHYSICAL REVIEW B LA English DT Article ID FIRST-PRINCIPLES; KERR ROTATION; ORIENTATION DEPENDENCE; FILMS; NICKEL; BAND; SYSTEMS; SURFACE; ANISOTROPY; METALS AB Recent experiments suggest that the linear magneto-optical signal from thin surfaces differs significantly from the corresponding hulk signal. Using an ab initio full potential linear muffin-tin orbital method, we have therefore calculated the polar magneto-optical Kerr signal for tetragonal and cubic Fe, Co, and Ni, in order to elucidate the role of tetragonal distortion on magneto-optical spectra. Our calculations indicate that for all three metals, the amplitudes and positions of the peaks in the Kerr spectra do change due to the tetragonal distortion, but the effect is not dramatic, and far from the observed differences. We therefore conclude that the large observed differences must have another origin, and discuss possible sources. Furthermore, since magnetooptical spectra are very sensitive to details in the wave functions and density, calculation of such spectra constitutes an important test of any ab initio method. The highly accurate method used in the present calculations differs from previously used methods in several respects, and a comparison between the different methods is made. [S0163-1829(99)04340-4]. C1 Uppsala Univ, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Roorkee, Dept Phys, Roorkee 247667, Uttar Pradesh, India. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. RP Uppsala Univ, Dept Phys, Condensed Matter Theory Grp, POB 530, S-75121 Uppsala, Sweden. RI Eriksson, Olle/E-3265-2014; Delin, Anna/P-2100-2014 OI Eriksson, Olle/0000-0001-5111-1374; Delin, Anna/0000-0001-7788-6127 NR 73 TC 30 Z9 30 U1 1 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 NOV 15 PY 1999 VL 60 IS 20 BP 14105 EP 14114 DI 10.1103/PhysRevB.60.14105 PG 10 WC Physics, Condensed Matter SC Physics GA 261NP UT WOS:000084015500031 ER PT J AU Hwang, CY Swan, AK Hong, SC AF Hwang, CY Swan, AK Hong, SC TI Suppression of ferromagnetic order of Fe overlayers on the Rh(001) surface SO PHYSICAL REVIEW B LA English DT Article ID IRON FILMS; TRANSITION; FCC; ANTIFERROMAGNETISM; INSTABILITIES; MAGNETISM; CU(001); EPITAXY; GROWTH AB The magnetic phase of thin Fe overlayers on top of a Rh(001) surface has been probed using the surface magneto-optical Kerr effect. Quite surprisingly, we have found a suppression of ferromagnetic order up to six atomic layers of Fe. Not until Fe coverage reaches above seven layers does a ferromagnetic order start to develop. The suppression of ferromagnetic order is attributed to the tetragonally distorted cubic structure, which has been predicted to favor anitiferromagnetic ordering from our first-principles calculation using the full potential linearized augmented plane-wave method. [S0163-1829(99)12943-6]. C1 Korea Res Inst Stand & Sci, Mat Evaluat Ctr, Taejon, South Korea. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Ulsan, Dept Phys, Ulsan 680749, South Korea. RP Hwang, CY (reprint author), Korea Res Inst Stand & Sci, Mat Evaluat Ctr, POB 102, Taejon, South Korea. NR 30 TC 21 Z9 21 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 1999 VL 60 IS 20 BP 14429 EP 14433 DI 10.1103/PhysRevB.60.14429 PG 5 WC Physics, Condensed Matter SC Physics GA 261NP UT WOS:000084015500072 ER PT J AU Choi, HJ Ihm, J Yoon, YG Louie, SG AF Choi, HJ Ihm, J Yoon, YG Louie, SG TI Possible explanation for the conductance of a single quantum unit in metallic carbon nanotubes SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; MICROTUBULES; TUBULES AB The quantum conductance of a metallic carbon nanotube with one end immersed in a jellium metal is studied. We find that the incident pi*-band electrons, having a very high angular momentum with respect to the tube axis, go through the tube without being scattered by the free electrons in surrounding metal and contribute a quantum unit (2e(2)/h) to the conductance. On the other hand, the incident pi-band electrons, with the p(z) atomic orbitals in phase along the tube circumference, experience strong resonant back-scattering because the low-angular-momentum states at the Fermi level have a dominantly metallic character in the nanotube-jellium metal coexistence region. These results provide a possible explanation for the experimentally observed conductance of one quantum unit instead of two for nanotubes with one end dipped into liquid metal such as mercury. [S0163-1829(99)51044-8]. C1 Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Seoul Natl Univ, Ctr Theoret Phys, Seoul 151742, South Korea. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Choi, HJ (reprint author), Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. RI Yoon, Young-Gui/C-2978-2008; Choi, Hyoung Joon/N-8933-2015 OI Yoon, Young-Gui/0000-0002-1071-8628; Choi, Hyoung Joon/0000-0001-8565-8597 NR 17 TC 8 Z9 8 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 1999 VL 60 IS 20 BP R14009 EP R14011 DI 10.1103/PhysRevB.60.R14009 PG 3 WC Physics, Condensed Matter SC Physics GA 261NP UT WOS:000084015500018 ER PT J AU Bettencourt, LMA Habib, S Lythe, G AF Bettencourt, LMA Habib, S Lythe, G TI Controlling one-dimensional Langevin dynamics on the lattice SO PHYSICAL REVIEW D LA English DT Article ID STATISTICAL-MECHANICS; NUMERICAL SIMULATIONS; DISCRETE BREATHERS; CONTINUUM-LIMIT; 1+1 DIMENSIONS; MONTE-CARLO; KINKS; FIELDS; MODEL AB Stochastic evolutions of classical field theories have recently become popular in the study of problems such as the determination of the rates of topological transitions and the statistical mechanics of nonlinear coherent structures. To obtain high precision results from numerical calculations, a careful accounting of spacetime discreteness effects is essential, as well as the development of schemes to systematically improve convergence to the continuum. With a kink-bearing phi(4) held theory as the application arena; we present such an analysis for a (1+1)-dimensional Langevin system. Analytical predictions and results from high resolution numerical solutions are found to be in excellent agreement. [S0556-2821(99)02822-2]. C1 Los Alamos Natl Lab, Div Theoret, CNLS, Los Alamos, NM 87545 USA. RP Bettencourt, LMA (reprint author), Los Alamos Natl Lab, Div Theoret, CNLS, T-6-T-11,MS B288, Los Alamos, NM 87545 USA. EM lmbett@lanl.gov; habib@lanl.gov; grantlythe@bigfoot.com NR 42 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 1550-7998 EI 1550-2368 J9 PHYS REV D JI Phys. Rev. D PD NOV 15 PY 1999 VL 60 IS 10 AR 105039 DI 10.1103/PhysRevD.60.105039 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 258WH UT WOS:000083862300120 ER PT J AU Parry, MF Sornborger, AT AF Parry, MF Sornborger, AT TI Domain wall production during inflationary reheating SO PHYSICAL REVIEW D LA English DT Article ID PHASE-TRANSITIONS; PARTICLE-PRODUCTION; INFLATON DECAY; UNIVERSE; LATTICE AB We numerically investigate the decay, via parametric resonance, of the inflaton with an m(2) phi(2) potential into a scalar matter field with a symmetry breaking potential. We consider the case where symmetry breaking takes place during inflation, but where thermal symmetry restoration cannot occur during or after preheating. We show that when expansion is not taken into account during reheating, non-thermal symmetry restoration and defect production is possible. However in an expanding universe the fields do not spend sufficient time in the instability bands, thus symmetry restoration and subsequent domain wall production do not occur. [S0556-2821(99)06220-7]. C1 Brown Univ, Dept Phys, Providence, RI 02912 USA. Fermi Natl Accelerator Lab, NASA Fermilab Astrophys Grp, Batavia, IL 60510 USA. RP Parry, MF (reprint author), Brown Univ, Dept Phys, Providence, RI 02912 USA. EM parry@het.brown.edu; ats@traviata.fnal.gov NR 18 TC 9 Z9 9 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 NOV 15 PY 1999 VL 60 IS 10 AR 103504 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 258WH UT WOS:000083862300009 ER PT J AU DeMille, D Budker, D Derr, N Deveney, E AF DeMille, D Budker, D Derr, N Deveney, E TI Search for exchange-antisymmetric two-photon states SO PHYSICAL REVIEW LETTERS LA English DT Article ID BOSE STATISTICS; SMALL VIOLATIONS; SYMMETRIZATION POSTULATE; SPIN-0 PARTICLES; PAULI PRINCIPLE; LIMIT; FERMI AB Atomic two-photon J = 0 <-> J' = 1 transitions are forbidden for photons of the same energy. This selection rule is related to the fact that photons obey Bose-Einstein statistics. We hare searched for small violations of this selection rule by studying transitions in atomic Ba. We set a limit on the probability nu that photons are in exchange-antisymmetric states: nu = 1.2 < x 10(-7). C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Amherst Coll, Dept Phys, Amherst, MA 01002 USA. RP DeMille, D (reprint author), Yale Univ, Dept Phys, New Haven, CT 06520 USA. RI Budker, Dmitry/F-7580-2016 OI Budker, Dmitry/0000-0002-7356-4814 NR 24 TC 31 Z9 31 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 NOV 15 PY 1999 VL 83 IS 20 BP 3978 EP 3981 DI 10.1103/PhysRevLett.83.3978 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400002 ER PT J AU Ramsey-Musolf, MJ AF Ramsey-Musolf, MJ TI Electric dipole moments and the mass scale of new T-violating, P-conserving interactions SO PHYSICAL REVIEW LETTERS LA English DT Article ID EXPERIMENTAL LIMIT; NEUTRON; ODD AB We consider the implications of experimental limits on the permanent electric dipole moment (EDM) of the electron and neutron for possible new time-reversal violating (TV) parity-conserving (PC) interactions. We show that the constraints derived from one-loop contributions to the EDM exceed previously reported two-loop limits by more than an order of magnitude and imply a lower bounden the new TVPC mass scale A(TVPC) Of 150 TeV for new TVPC strong interactions. These results imply a value of 10(-15) or smaller for the ratio of low-energy TVPC matrix elements to those of the residual strong interaction. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Thomas Jefferson Natl Accelerator Facil, Theory Grp, Newport News, VA 23606 USA. RP Ramsey-Musolf, MJ (reprint author), Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. NR 14 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 NOV 15 PY 1999 VL 83 IS 20 BP 3997 EP 4000 DI 10.1103/PhysRevLett.83.3997 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400007 ER PT J AU Gronau, M AF Gronau, M TI Resonant two-body D decays SO PHYSICAL REVIEW LETTERS LA English DT Article ID NONLEPTONIC WEAK DECAYS; CHARMED MESON DECAYS; B-MESONS; 2-BODY AB The contribution of a K*(1430) 0(+) resonance to D-0 --> K(-)pi(+) is calculated by applying the soft pion theorem to D+ --> K*pi(+), and is found to be about 30% of the measured amplitude and to be larger than the Delta I = 3/2 component of this amplitude. We estimate a 70% contribution to the total amplitude from a higher K*(1950) resonance. This implies large deviations from factorization in D decay amplitudes, a lifetime difference between D-0 and D+, and an enhancement of D-0-(D) over bar(0) mixing due to SU(3) breaking. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Technion Israel Inst Technol, Dept Phys, IL-32000 Haifa, Israel. RP Gronau, M (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 32 TC 21 Z9 21 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 NOV 15 PY 1999 VL 83 IS 20 BP 4005 EP 4008 DI 10.1103/PhysRevLett.83.4005 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400009 ER PT J AU Lefort, T Kwiatkowski, K Hsi, WC Pienkowski, L Beaulieu, L Back, B Breuer, H Gushue, S Korteling, RG Laforest, R Martin, E Ramakrishnan, E Remsberg, LP Rowland, D Ruangma, A Viola, VE Winchester, E Yennello, SJ AF Lefort, T Kwiatkowski, K Hsi, WC Pienkowski, L Beaulieu, L Back, B Breuer, H Gushue, S Korteling, RG Laforest, R Martin, E Ramakrishnan, E Remsberg, LP Rowland, D Ruangma, A Viola, VE Winchester, E Yennello, SJ TI Heating Au-197 nuclei with 8 GeV/c antiproton and pi(-) beams SO PHYSICAL REVIEW LETTERS LA English DT Article ID TO-PROTON RATIO; HOT NUCLEI; ANNIHILATION; MATTER; 4-PI AB Comparison of the heating effect produced by 8 GeV/c pi(-) and antiproton beams incident on Au-197 nuclei has been conducted with the Indiana silicon sphere 4 pi detector array. Event reconstruction indicates formation of thermal-like heavy residues with excitation energies up to 1.7 GeV. Enhanced energy deposition is observed for antiprotons relative to negative pions. For events with excitation energies that exceed 1000 MeV, there is a 50% increase in cross section for the antiproton beam relative to the pi(-) beam. The predominant decay mode at these high excitation energies is multifragmentation in which three or more Z greater than or equal to 3 fragments are emitted. C1 Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. Indiana Univ, IUCF, Bloomington, IN 47405 USA. Warsaw Univ, Heavy Ion Lab, PL-02097 Warsaw, Poland. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Simon Fraser Univ, Dept Chem, Burnaby, BC V5A 1S6, Canada. Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. Texas A&M Univ, Cyclotron Lab, College Stn, TX 77843 USA. RP Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. RI Beaulieu, Luc/A-6803-2009; Rowland, Douglas/F-3104-2014; Yennello, Sherry/B-5803-2015 OI Beaulieu, Luc/0000-0003-0429-6366; Rowland, Douglas/0000-0001-8059-6905; Yennello, Sherry/0000-0003-3963-5217 NR 19 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 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 15 PY 1999 VL 83 IS 20 BP 4033 EP 4036 DI 10.1103/PhysRevLett.83.4033 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400016 ER PT J AU Ben-Naim, E Chen, SY Doolen, GD Redner, S AF Ben-Naim, E Chen, SY Doolen, GD Redner, S TI Shocklike dynamics of inelastic gases SO PHYSICAL REVIEW LETTERS LA English DT Article ID GRANULAR FLOWS; HYDRODYNAMICS; KINETICS AB We provide a simple physical picture which suggests that the asymptotic dynamics of inelastic gases in one dimension is independent of the degree of inelasticity. Statistical characteristics, including velocity fluctuations and the velocity distribution, are identical to those of a perfectly inelastic sticky gas, which in turn is described by the inviscid Burgers equation. Asymptotic predictions of this continuum theory, including the t(-2/3) temperature decay and the development of discontinuities in the velocity profile, are verified numerically for inelastic gases. 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. Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. RP Ben-Naim, E (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Ben-Naim, Eli/C-7542-2009; Chen, Shiyi/A-3234-2010 OI Ben-Naim, Eli/0000-0002-2444-7304; NR 25 TC 74 Z9 74 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 NOV 15 PY 1999 VL 83 IS 20 BP 4069 EP 4072 DI 10.1103/PhysRevLett.83.4069 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400025 ER PT J AU Badro, J Struzhkin, VV Shu, JF Hemley, RJ Mao, HK Kao, CC Rueff, JP Shen, GY AF Badro, J Struzhkin, VV Shu, JF Hemley, RJ Mao, HK Kao, CC Rueff, JP Shen, GY TI Magnetism in FeO at megabar pressures from X-ray emission spectroscopy SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOSSBAUER; PHASE; FLUORESCENCE; TEMPERATURE; COLLAPSE; WUSTITE; FE2O3; GPA AB We report evidence for a preserved magnetic state in FeO up to 143 GPa at room temperature using high-resolution x-ray emission spectroscopy. This observation is based on the spectral line shape of the Fe K beta emission line. Up to the highest pressure, FeO remains a magnetic insulator. Combining our results with previous Mossbauer data, we present a new magnetic phase diagram of FeO. Features like a closed-loop P-T antiferromagnetic domain confirm that high-pressure investigations can reveal new physical properties and unexpected phenomena. C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Carnegie Inst Washington, Ctr High Pressure Res, Washington, DC 20015 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Chicago, GSECARS, Chicago, IL 60637 USA. RP Badro, J (reprint author), Carnegie Inst Washington, Geophys Lab, 5251 Broad Branch Rd NW, Washington, DC 20015 USA. RI Shen, Guoyin/D-6527-2011; Struzhkin, Viktor/J-9847-2013; Rueff, Jean-Pascal/D-8938-2016; Badro, James/A-6003-2011 OI Struzhkin, Viktor/0000-0002-3468-0548; Rueff, Jean-Pascal/0000-0003-3594-918X; NR 23 TC 117 Z9 121 U1 1 U2 36 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 NOV 15 PY 1999 VL 83 IS 20 BP 4101 EP 4104 DI 10.1103/PhysRevLett.83.4101 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400033 ER PT J AU Kim, HJ Ramdas, AK Rodriguez, S Grimsditch, M Anthony, TR AF Kim, HJ Ramdas, AK Rodriguez, S Grimsditch, M Anthony, TR TI Spontaneous symmetry breaking of acceptors in "Blue" diamonds SO PHYSICAL REVIEW LETTERS LA English DT Article ID ISOTOPICALLY CONTROLLED DIAMONDS; SEMICONDUCTING DIAMOND; ELECTRONIC RAMAN; INFRARED-SPECTRA; GROUND-STATE; BORON; SILICON; SPECTROSCOPY AB The electronic Raman transition between the lower 1s(p(3/2)) and the higher 1s(p(1/2)) State of a hole bound to a boron acceptor in diamond, examined under the high resolution of a Fabry-Perot interferometer, reveals a doublet separated by (0.81 +/- 0.15) cm(-1), indicative of a spontaneous symmetry breaking of the fourfold degenerate ground state. The direct transition between the levels into which 1s(p(3/2)) : Gamma(8) resolves, with a Raman shift of (0.80 +/- 0.04) cm(-1), provides a remarkable confirmation of the symmetry lowering shown to arise from a static Jahn-Teller distortion. C1 Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Gen Elect Co, Corp Res & Dev, Schenectady, NY 12309 USA. RP Kim, HJ (reprint author), Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NR 23 TC 19 Z9 19 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 NOV 15 PY 1999 VL 83 IS 20 BP 4140 EP 4143 DI 10.1103/PhysRevLett.83.4140 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400043 ER PT J AU Sonier, JE Brewer, JH Kiefl, RF Morris, GD Miller, RI Bonn, DA Chakhalian, J Heffner, RH Hardy, WN Liang, R AF Sonier, JE Brewer, JH Kiefl, RF Morris, GD Miller, RI Bonn, DA Chakhalian, J Heffner, RH Hardy, WN Liang, R TI Field induced reduction of the low-temperature superfluid density in YBa2Cu3O6.95 SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC PENETRATION DEPTH; VORTEX LATTICE; SUPERCONDUCTORS; DEPENDENCE; YBA2CU3O7-DELTA; CORE AB A novel high magnetic field (8 T) spectrometer for muon spin relation has been used to measure the temperature dependence of the in-plane magnetic penetration depth lambda(ab) in YBa2Cu3O6.95. At low H and low T, lambda(ab) exhibits the characteristic linear T dependence associated with the energy gap of a d(x2-y2)-wave superconductor. However, at higher fields lambda(ab) is essentially temperature independent at low T. We discuss possible interpretations of this surprising new feature in the low-energy excitation spectrum. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. RP Sonier, JE (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Chakhalian, Jak/F-2274-2015; OI Brewer, Jesse H./0000-0002-8211-1235 NR 26 TC 89 Z9 89 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 NOV 15 PY 1999 VL 83 IS 20 BP 4156 EP 4159 DI 10.1103/PhysRevLett.83.4156 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400047 ER PT J AU Li, Q Tsay, YN Suenaga, M Klemm, RA Gu, GD Koshizuka, N AF Li, Q Tsay, YN Suenaga, M Klemm, RA Gu, GD Koshizuka, N TI Bi2Sr2CaCu2O8+delta bicrystal c-axis twist Josephson junctions: A new phase-sensitive test of order parameter symmetry SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTORS; YBA2CU3O7-DELTA; PLANE; GAP AB We prepared atomically clean Bi2Sr2CaCu2O8+delta Josephson junctions between identical single crystal cleaves stacked and twisted an angle phi(0) about the c axis. For each bicrystal, the ratio J(c)(J)/J(c)(S) of the c axis twist junction critical current density to that across either single crystal part is unity, independent of phi(0) and the ratio A(J)/A(S) of junction areas; Our results provide strong evidence for incoherent c-axis tunneling and that the dominant superconducting order parameter contains an isotropic s-wave component for T less than or equal to T-c, but not the purported d(x2-y2)-wave component. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. ISTEC, Superconduct Res Lab, Koto Ku, Tokyo 135, Japan. RP Li, Q (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NR 23 TC 129 Z9 129 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 NOV 15 PY 1999 VL 83 IS 20 BP 4160 EP 4163 DI 10.1103/PhysRevLett.83.4160 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400048 ER PT J AU Carrington, A Bonalde, IJ Prozorov, R Giannetta, RW Kini, AM Schlueter, J Wang, HH Geiser, U Williams, JM AF Carrington, A Bonalde, IJ Prozorov, R Giannetta, RW Kini, AM Schlueter, J Wang, HH Geiser, U Williams, JM TI Low-temperature penetration depth of kappa-(ET)(2)Cu[N(CN)(2)]Br and kappa-(ET)(2)Cu(NCS)(2) SO PHYSICAL REVIEW LETTERS LA English DT Article ID MICROWAVE SURFACE IMPEDANCE; D-WAVE SUPERCONDUCTORS; ORGANIC SUPERCONDUCTOR; C-13 NMR; TRANSITION-TEMPERATURE; BEDT-TTF; T-C; KAPPA-(BEDT-TTF)(2)CU(NCS)(2); KAPPA-(BEDT-TTF)2CU(NCS)2; YBA2CU3O6.95 AB We present high-precision measurements of the penetration depth of single crystals of kappa-(ET)(2)Cu[N(CN)(2)]Br and kappa-(ET)(2)Cu(NCS)(2) at temperatures down to 0.4 K. We find that, at low temperatures, the in-plane penetration depth (lambda\\) varies as a fractional power law, lambda\\ similar to T-3/2. While this may he taken as evidence for novel pair excitation processes, we show thar the data are also consistent with a quasilinear variation of the superfluid density, as is expected for a d-wave superconductor with impurities or a small residual gap. Our data for the interplane penetration depth show similar features and give a direct measurement of the absolute value, lambda(perpendicular to)(0) = 100 +/- 20 mu m. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Argonne Natl Lab, Chem & Mat Sci Div, Argonne, IL 60439 USA. RP Carrington, A (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Kini, Aravinda/F-4467-2012; Prozorov, Ruslan/A-2487-2008 OI Prozorov, Ruslan/0000-0002-8088-6096 NR 38 TC 111 Z9 111 U1 1 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 15 PY 1999 VL 83 IS 20 BP 4172 EP 4175 DI 10.1103/PhysRevLett.83.4172 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400051 ER PT J AU Welp, U Berger, A Miller, DJ Vlasko-Vlasov, VK Gray, KE Mitchell, JF AF Welp, U Berger, A Miller, DJ Vlasko-Vlasov, VK Gray, KE Mitchell, JF TI Direct imaging of the first-order spin-flop transition in the layered manganite La(1.4)Sr(1.6)Mn(2)O(7) SO PHYSICAL REVIEW LETTERS LA English DT Article ID INTERPLANE TUNNELING MAGNETORESISTANCE; CRYSTAL; LA1.2SR1.8MN2O7 AB Magnetic field induced transitions in aritiferromagnetic La(1.4)Sr(1.6)Mn(2)O(7) were studied using magnetization measurements and a high-resolution magneto-optical imaging technique. We report the direct observation of the formation of ferromagnetic domains appearing at the first-order spin-flop transition. The magnetization proceeds through nucleation of polarized domains at crystal defect sites and not by domain wall motion. A small magnetic hysteresis is caused by the nucleation and annihilation of domains in the mixed state. The results establish a direct link between the magnetic structure on the atomic scale and the macroscopic transport and magnetic properties of the sample. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Welp, U (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Gao, Jinlong/C-1489-2010; Berger, Andreas/D-3706-2015 OI Berger, Andreas/0000-0001-5865-6609 NR 24 TC 33 Z9 33 U1 2 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 15 PY 1999 VL 83 IS 20 BP 4180 EP 4183 DI 10.1103/PhysRevLett.83.4180 PG 4 WC Physics, Multidisciplinary SC Physics GA 255NQ UT WOS:000083676400053 ER PT J AU Zetner, PW Trajmar, S Kanik, I Wang, S Csanak, G Clark, REH Abdallah, J Fursa, D Bray, I AF Zetner, PW Trajmar, S Kanik, I Wang, S Csanak, G Clark, REH Abdallah, J Fursa, D Bray, I TI Differential cross sections for electron-impact excitation out of the metastable levels of the barium atom SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID LASER-EXCITED BARIUM; COHERENCE PARAMETERS; SCATTERING; ...6S5D(1)D(2); TRANSITION; IONS AB We report an experimental and theoretical investigation of low-energy electron scattering from Ba-138 atoms prepared in the metastable D-3(2) and D-1(2) levels by laser-optical pumping. Differential cross sections were measured for excitation out of these metastable levels to a variety of higher-lying levels at electron-impact energies of 10, 20 and 36.7 eV. A comparison of experimental data with the results of theoretical approaches using the unitarized distorted-wave approximation and the convergent close-coupling scheme is given. C1 Univ Manitoba, Dept Phys & Astron, Winnipeg, MB R3T 2N2, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Flinders Univ S Australia, Sch Phys Sci, Adelaide, SA 5001, Australia. RP Zetner, PW (reprint author), Univ Manitoba, Dept Phys & Astron, Winnipeg, MB R3T 2N2, Canada. RI Fursa, Dmitry/C-2301-2009; Bray, Igor/B-8586-2009 OI Fursa, Dmitry/0000-0002-3951-9016; Bray, Igor/0000-0001-7554-8044 NR 40 TC 15 Z9 15 U1 0 U2 3 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 NOV 14 PY 1999 VL 32 IS 21 BP 5123 EP 5146 DI 10.1088/0953-4075/32/21/306 PG 24 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 259VE UT WOS:000083914000009 ER PT J AU Shashkov, DA Chisholm, MF Seidman, DN AF Shashkov, DA Chisholm, MF Seidman, DN TI Atomic-scale structure and chemistry of ceramic/metal interfaces - I. Atomic structure of {222} MgO/Cu (Ag) interfaces SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE scanning transmission electron microscopy (STEM); binary oxide; segregation; dislocations; {222} MgO/Cu (Ag) interfaces ID GRAIN-BOUNDARIES; ELECTRON-MICROSCOPY; SEGREGATION; RESOLUTION; ALLOYS; STEM; (222)MGO/CU; CRYSTALS; IMAGES; ENERGY AB Ceramic/metal (C/M) {222} MgO/Cu (Ag) heterophase interfaces. prepared by internal oxidation, are studied by scanning transmission electron microscopy (STEM). The observed spacing between misfit dislocations (1.45 nm) in a (110) projection is in agreement with the prediction of Bollmann's geometric O-lattice theory and experimental values In the literature for {222} MgO/Cu interfaces. It is concluded that the {222} MgO/Cu (Ag) interfaces are semicoherent and contain a trigonal network of pure edge misfit dislocations parallel to (110)-type directions, with an (a/6)(211)-type Burgers vector. Misfit dislocations are also found in a standoff position at a distance of a single (111) spacing of the Cu (Ag) matrix. Extra intensity at the interface, in some angular dark-field images indicates silver segregation, in agreement with our atom-probe field-ion microscope results. On the metal side of the interface, extra intensity is observed in five atomic layers, which corresponds to a total silver enrichment of approximately 0.7 effective monolayers. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Seidman, David/B-6697-2009 NR 56 TC 28 Z9 28 U1 3 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD NOV 12 PY 1999 VL 47 IS 15-16 BP 3939 EP 3951 DI 10.1016/S1359-6454(99)00255-4 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800002 ER PT J AU Campbell, GH Belak, J Moriarty, JA AF Campbell, GH Belak, J Moriarty, JA TI Atomic structure of the Sigma 5 (310)/[001] symmetric tilt grain boundary in molybdenum SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE transmission electron microscopy (TEM); grain boundaries; theory and modeling of defects ID BCC TRANSITION-METALS; INTERATOMIC POTENTIALS; SCREW DISLOCATIONS; SIMULATION; MO; DEFECTS; FORCES AB Atomistic simulations offer an important route towards understanding and modeling materials behavior. Incorporating the essential physics into the models of interatomic interactions is increasingly difficult as materials with more complex electronic structures than f.c.c. transition metals are addressed. For b.c.c. metals, interatomic potentials have been developed that incorporate angularly dependent interactions to accommodate the physics of partially filled d-bands. A good test of these new models is to predict the structure of crystal defects and compare them with experimentally observed defect structures. To that end, the Sigma 5 (310)/[001] symmetric tilt grain boundary in Mo has been fabricated and characterized by HREM. The experimentally observed structure is found to agree with predictions based on atomistic simulations using angular-force interatomic potentials developed from model generalized pseudopotential theory (MGPT), but disagrees with predictions based on radial-force potentials, such as those obtained from the Finnis-Sinclair method or the embedded atom method (EAM). (C) 1999 Acta Metallurgica Inc. Published bl Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94550 USA. RP Campbell, GH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RI Campbell, Geoffrey/F-7681-2010 NR 25 TC 27 Z9 27 U1 0 U2 10 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 3977 EP 3985 DI 10.1016/S1359-6454(99)00258-X PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800005 ER PT J AU Radmilovic, V Kilaas, R Dahmen, U Shiflet, GJ AF Radmilovic, V Kilaas, R Dahmen, U Shiflet, GJ TI Structure and morphology of S-phase precipitates in aluminum SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE S-phase; Al2CuMg intermetallic; quantitative high resolution electron microscopy; interface; invariant line; precipitates; structural ledges; growth ledges; Moire analysis ID LI-CU-MG; ALLOY; LITHIUM AB This work presents a crystallographic and morphological analysis of S-phase precipitation in Al alloys. Using quantitative high resolution electron microscopy, four models for the crystal structure of the S-phase (Al2CuMg) in Al-based alloys are critically evaluated, and a new model is proposed. This model is identical to that of Perlitz and Westgren, but with an exchange of Cu and Mg. Two distinct precipitate morphologies are observed. Both are laths elongated along (100) directions common to the matrix and the precipitate and lie on {021} planes of the matrix. Type I precipitates have interfaces of the type (021)(Al)parallel to(001)(s) while type II precipitates have interfaces of the type (021)(Al)parallel to(043)(s), i.e. the two types differ in the S-phase lattice plane that is conjugate to the {021}(Al) habit plane. The interface plane of type I precipitates tends to be atomically flat containing only growth ledges while that of type II precipitates is stepped, The orientation relationship of the two types of precipitate differs by a rotation of about 5 degrees around the lath axis. The difference between the two types of precipitate is discussed in terms of their lattice correspondence, and type II precipitates are shown to follow an invariant line strain. Moire analysis of lattice distortions revealed that {020}(Al) planes remain undistorted while {002}(Al) planes suffer significant shear during S-phase nucleation. Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. Univ Virginia, Charlottesville, VA 22903 USA. Univ Belgrade, Dept Met Phys, Belgrade, Yugoslavia. RP Radmilovic, V (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. NR 47 TC 71 Z9 75 U1 1 U2 20 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 3987 EP 3997 DI 10.1016/S1359-6454(99)00259-1 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800006 ER PT J AU Dickey, EC Fan, X Pennycock, SJ AF Dickey, EC Fan, X Pennycock, SJ TI Direct atomic-scale imaging of ceramic interfaces SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE ceramic; interface; scanning transmission electron microscopy (STEM); electron energy loss spectroscopy (EELS) ID ELECTRON-ENERGY-LOSS; SCATTERED ELECTRONS; GRAIN-BOUNDARIES; CRYSTALS; RECONSTRUCTION; REDUCTION; COMPOSITE; SPECTRA; METALS; OXIDES AB Understanding the atomic structure and chemistry of internal interfaces is often critical to developing interface structure-property relationships. Results are presented from several studies in which Z-contrast scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) have been employed to solve the atomic structures of oxide interfaces, The Z-contrast imaging technique directly reveals the projected cation sublattices constituting the interface, while EELS provides chemical and local electronic structure information. Because Z-contrast imaging and EELS can be performed simultaneously, direct correlations between structure and chemistry can be made at the atomic scale. The utility of Z-contrast imaging and EELS is demonstrated in three examples: a ZrO2 24 degrees [100] symmetric tilt grain boundary, a NiO-cubic ZrO2 eutectic interface and a Ni-cubic ZrO2 metal-ceramic interface. The power and versatility of Z-contrast and EELS for solving interface structures in oxide systems is clearly demonstrated in these three material systems. Published bl Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. RP Pennycock, SJ (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Dickey, Elizabeth/A-3368-2011 OI Dickey, Elizabeth/0000-0003-4005-7872 NR 23 TC 23 Z9 23 U1 2 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD NOV 12 PY 1999 VL 47 IS 15-16 BP 4061 EP 4068 DI 10.1016/S1359-6454(99)00266-9 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800014 ER PT J AU Vetrano, JS Simonen, EP Bruemmer, SM AF Vetrano, JS Simonen, EP Bruemmer, SM TI Evidence for excess vacancies at sliding grain boundaries during superplastic deformation SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE transmission electron microscopy (TEM); aluminium alloys; grain boundaries; segregation; interfacial diffusion ID MG ALLOYS; SEGREGATION; ALUMINUM AB Rapid quenching of AI-Mg alloys during superplastic deformation has revealed the presence of nano-scale cavities along many grain boundaries. They were observed only under deformation conditions where grain boundary sliding was the dominant mechanism. Fine-probe compositional measurements revealed that the cavity surface is enriched in Mg, and in situ heating in the transmission electron microscope demonstrated that they are not stable above 175 degrees C. Kinetic analysis of cavity formation during a quench concludes that the cavities did not exist during deformation but were formed as the sample cooled. It is proposed that these cavities are evidence for a localized excess of vacancies during grain boundary sliding. (C) 1999 Elsevier Science Ltd All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Vetrano, JS (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 23 TC 11 Z9 11 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 4125 EP 4129 DI 10.1016/S1359-6454(99)00271-2 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800019 ER PT J AU Saiz, E Cannon, RM Tomsia, AP AF Saiz, E Cannon, RM Tomsia, AP TI Energetics and atomic transport at liquid metal/Al(2)O(3) interfaces SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CA DE liquid metals; oxides; diffusion; surfaces & interfaces; atomic force microscopy (AFM) ID SURFACE THERMAL GROOVES; GRAIN-BOUNDARY; POLYCRYSTALLINE ALUMINA; DIHEDRAL ANGLES; MASS-TRANSPORT; PURE METALS; TENSION; SAPPHIRE; OXYGEN; WETTABILITY AB The objective is to study interfacial mass transport mechanisms and to estimate interfacial energies for metal/Al(2)O(3) systems. Experiments have been performed with molten drops of Ni, Cu, or Au on pure, polycrystalline alumina at oxygen partial pressures for which no adsorption is expected and with Al to determine the effect of extremely low p(O(2)). After removing the metal drops, grain boundary grooves at the interface and oxide surface have been analyzed using AFM and SEM. Several sources of error are assessed, and corrections are proposed for large systematic errors that occur for root angles. These experiments yield higher grain boundary energies and lower M/Al(2)O(3) interfacial energies than previously reported. Transport rates near the metal/ceramic interface are two to four orders of magnitude faster than on the oxide surface and the results suggest that diffusion through the liquid metal is usually the main atomic transport mechanism. Experiments with Al indicate that, at the far lower oxygen activities, transport is faster at both the interface and alumina surface and that the interfaces are more anisotropic and have lower energy. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Tomsia, AP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 51 TC 96 Z9 96 U1 3 U2 23 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 4209 EP 4220 DI 10.1016/S1359-6454(99)00279-7 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800027 ER PT J AU Bloyer, DR Gomez-Vega, JM Saiz, E McNaney, JM Cannon, RM Tomsia, AP AF Bloyer, DR Gomez-Vega, JM Saiz, E McNaney, JM Cannon, RM Tomsia, AP TI Fabrication and characterization of a bioactive glass coating on titanium implant alloys SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA DE biomaterials; titanium alloys; non-metallic (silicates); bonding; stress corrosion ID STRESS-CORROSION AB Ongoing research is reported aimed at improving biofixation through the use of bioactive glass coatings on Ti-based implant alloys. The optimized processing conditions for coating with one promising bioactive glass composition are discussed, and the stress corrosion crack growth behavior in a simulated human physiological environment is presented. This glass can be successfully used to coat Ti implant alloys, and preliminary tests indicate that interfacial fracture resistance is good. (C) 1999 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 Tomsia, AP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI McNaney, James/F-5258-2013 NR 15 TC 39 Z9 45 U1 1 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 4221 EP 4224 DI 10.1016/S1359-6454(99)00280-3 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800028 ER PT J AU Krishnan, KM AF Krishnan, KM TI Magnetism and microstructure: The role of interfaces SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Materials Science and Mechanics of Interfaces CY OCT 25-30, 1998 CL LA JOLLA, CALIFORNIA ID MOLECULAR-BEAM EPITAXY; CO/PT MULTILAYERS; PERMANENT-MAGNETS; THIN-FILMS; ANISOTROPY AB The role of microstructure in determining the magnetic properties of materials is introduced and the role of interfaces, including intergranular phases, is presented in the context of three different classes of materials exhibiting novel magnetic behavior. This includes perpendicular interface anisotropy in metallic multilayers, origin of coercivity in hard magnets and the role of interface roughening in giant magnetoresistive materials. It is demonstrated that in these systems the microstructure of the interfaces (structural and compositional roughness, compound formation, strain and defects) and intergranular coupling and/or isolation are the appropriate length scales that determine their magnetic and magnetotransport properties. This approach not only makes ii possible to atomically engineer thin films and nanostructures but also offers opportunities to elucidate the physics of magnetism and build new materials with unique properties. Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Div Mat Sci, Berkeley, CA 94720 USA. RP Krishnan, KM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Div Mat Sci, Berkeley, CA 94720 USA. NR 27 TC 15 Z9 16 U1 0 U2 8 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 NOV 12 PY 1999 VL 47 IS 15-16 BP 4233 EP 4244 DI 10.1016/S1359-6454(99)00282-7 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 262JN UT WOS:000084063800030 ER PT J AU Curtiss, LA Redfern, PC Raghavachari, K Pople, JA AF Curtiss, LA Redfern, PC Raghavachari, K Pople, JA TI Gaussian-3 theory: a variation based on third-order perturbation theory and an assessment of the contribution of core-related correlation SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DENSITY-FUNCTIONAL THEORIES; ANHARMONIC-FORCE FIELD; BASIS-SET CONVERGENCE; POLARIZATION FUNCTIONS; 2ND-ROW COMPOUNDS; MODEL CHEMISTRY; ENERGIES; MOLECULES; GEOMETRY; THERMOCHEMISTRY AB A variation of Gaussian-3 (G3) theory is presented in which third-order perturbation theory is used in place of fourth-order perturbation theory to decrease the computational requirements. This method, referred to as G3(MP3) theory, is assessed on 299 energies from the G2/97 test set. The average absolute deviation from experiment of G3(MP3) theory for the 299 energies is 1.22 kcal/mol. The importance of core-related correlation in various G3 methods is also discussed. (C) 1999 XXX. Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Curtiss, LA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. EM curtiss@anl.gov NR 24 TC 53 Z9 54 U1 2 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 NOV 12 PY 1999 VL 313 IS 3-4 BP 600 EP 607 DI 10.1016/S0009-2614(99)01082-9 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 260XA UT WOS:000083977700032 ER PT J AU Myneni, SCB Brown, JT Martinez, GA Meyer-Ilse, W AF Myneni, SCB Brown, JT Martinez, GA Meyer-Ilse, W TI Imaging of humic substance macromolecular structures in water and soils SO SCIENCE LA English DT Article ID MICROSCOPY; ACIDS AB Humic substances (HSs) are the natural organic polyelectrolytes formed from the biochemical weathering of plant and animal remains. Their macromolecular structure and chemistry determine their role in biogeochemical processes. In situ spectromicroscopic evidence showed that the HS macromolecular structures (size and shape) vary as a function of HS origin (soil versus fluvial), solution chemistry, and the associated mineralogy. The HSs do not simply form coils in acidic or strong electrolyte solutions and elongated structures in dilute alkaline solutions. The macromolecular structural changes of HSs are likely to modify contaminant solubility, biotransformation, and the carbon cycle in soils and sediments. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. Univ Puerto Rico, Agr Expt Stn, Rio Piedras, PR 00928 USA. RP Myneni, SCB (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. NR 21 TC 165 Z9 176 U1 8 U2 91 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 NOV 12 PY 1999 VL 286 IS 5443 BP 1335 EP 1337 DI 10.1126/science.286.5443.1335 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 255NF UT WOS:000083675500035 ER PT J AU Wilcoxon, JP Provencio, PP AF Wilcoxon, JP Provencio, PP TI Use of surfactant micelles to control the structural phase of nanosize iron clusters SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID INVERSE MICELLES; PARTICLES; CATALYSTS AB We have synthesized iron nanoclusters using two chemical types of inverse micelle systems to control the growth process. Surprisingly, we have found that the phase of the resulting nanosize iron depends strongly on the chemical nature of the surfactant used during the growth of the clusters. For example, use of nonionic surfactant micelles for this room-temperature synthesis produces the normally-high-temperature gamma-phase with a fee structure as determined by selected area electron diffraction (SAD) and high-resolution lattice fringe images. Use of a cationic quaternary ammonium surfactant micelle system, on the other hand, produces the normal bcc alpha-iron phase as determined by SAD. This strong dependence of the structure of nanosize clusters on surfactant type may reflect different binding-site preferences for the chemically different surfactants during the growth stage of the cluster synthesis. This is analogous to the well-known role of surfactants as habit modifiers during macroscopic crystalline growth processes in solution, but is the first example of such control of structural phase during nanocluster synthesis. C1 Sandia Natl Labs, Div 1152, Albuquerque, NM 87185 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, Div 1152, POB 5800, Albuquerque, NM 87185 USA. NR 16 TC 87 Z9 93 U1 2 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 11 PY 1999 VL 103 IS 45 BP 9809 EP 9812 DI 10.1021/jp992133g PG 4 WC Chemistry, Physical SC Chemistry GA 256KU UT WOS:000083725100002 ER PT J AU Smith, BB Nozik, AJ AF Smith, BB Nozik, AJ TI A wave packet model for electron transfer and its implications for the semiconductor-liquid interface SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CHARGE-EXCHANGE; DYNAMICS; SURFACE; CHEMISORPTION; SCATTERING; FRICTION AB This paper establishes the computational feasibility and examines the implications of a particular technique for simulations of time dependent electron transfer (ET) at semiconductor-liquid interfaces (SLIs). The methodology uses a one electron formalism employing wave packets, pseudopotentials, and molecular dynamics, which we dub WPMD. We describe a detailed mechanism for SLI ET by using the methodology. The model is versatile enough to address conventional SLI ET, surface state and adsorption mediated ET, photoexcited ET, and ET between quantum dots and other microstructures. We contrast the perspectives of our WPMD model of SLI ET with those in traditional literature and find substantial differences. The use of standard Landau-Zener theory for SLI ET is found particularly problematic. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Smith, BB (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Nozik, Arthur/A-1481-2012; Nozik, Arthur/P-2641-2016 NR 66 TC 12 Z9 12 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 11 PY 1999 VL 103 IS 45 BP 9915 EP 9932 DI 10.1021/jp990836s PG 18 WC Chemistry, Physical SC Chemistry GA 256KU UT WOS:000083725100018 ER PT J AU DiMasi, E Tostmann, H Ocko, BM Pershan, PS Deutsch, M AF DiMasi, E Tostmann, H Ocko, BM Pershan, PS Deutsch, M TI Competition between surface layering and surface phase formation in dilute liquid Hg-Au alloys SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID X-RAY REFLECTIVITY; ATOMIC-FORCE MICROSCOPY; VAPOR INTERFACE; MERCURY; GALLIUM; FILMS; GOLD AB We present temperature-dependent X-ray reflectivity measurements of liquid Hg alloyed with 0.06-0.20 atom % Au. At low Au concentrations, we find temperature-dependent surface-induced layering similar to that observed in pure HE, except that the presence of Au reduces the layering amplitude. Upon approaching the solubility limit of Au in Hg. a new surface phase forms which is 1-2 atomic diameters thick and has a density of about half that of bulk Hg. We present a surface phase diagram, summarizing the evolution of this unexpected surface structure upon varying composition and temperature, Such surface modifications may account for the variations observed in catalytic and electrochemical reactions at liquid metal surfaces upon alloying. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Bar Ilan Univ, Dept Phys, IL-52100 Ramat Gan, Israel. RP DiMasi, E (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 32 TC 7 Z9 7 U1 1 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 NOV 11 PY 1999 VL 103 IS 45 BP 9952 EP 9959 DI 10.1021/jp9921553 PG 8 WC Chemistry, Physical SC Chemistry GA 256KU UT WOS:000083725100021 ER PT J AU Hunt, AW Cassidy, DB Selim, FA Haakenaasen, R Cowan, TE Howell, RH Lynn, KG Gotovchenko, JA AF Hunt, AW Cassidy, DB Selim, FA Haakenaasen, R Cowan, TE Howell, RH Lynn, KG Gotovchenko, JA TI Spatial sampling of crystal electrons by in-flight annihilation of fast positrons SO NATURE LA English DT Article ID CHARGE AB Energetic, positively charged particles travelling along a low-index crystal direction undergo many highly correlated, small-angle scattering events; the effect of these interactions is to guide or 'channel' (refs 1-8) the particles through the lattice, Channelling effectively focuses positive particles into the interstitial regions of the crystal: nuclear collisional processes such as Rutherford backscattering are suppressed, while the number of interactions with valence electrons increases. The interaction of channelled positrons with electrons produces annihilation radiation that can in principle(9-12) serve as a quantitative, spatially selective probe of electronic charge and spin densities within the crystal: in the interstitial regions, two-photon annihilation is enhanced relative to single-photon annihilation, because the latter process requires a nuclear recoil to conserve momentum. Here we report observations of single- and two-photon annihilation from channelled positrons, using a monoenergetic beam flux of 10(5) particles per second. Comparison of these two annihilation modes demonstrates the ability of channelled positrons to selectively sample valence electrons in a crystal. Useful practical implementation of the technique will require the development of more intense positron beams with fluxes approaching 10(7) particles per second. C1 Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Alexandria, Dept Engn Phys, Alexandria 21544, Egypt. Norwegian Def Res Estab, N-2027 Kjeller, Norway. Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Rowland Inst Sci Inc, Cambridge, MA 02142 USA. RP Gotovchenko, JA (reprint author), Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RI Selim, Farida/N-8077-2016; Cowan, Thomas/A-8713-2011; OI Cowan, Thomas/0000-0002-5845-000X; Cassidy, David/0000-0001-8332-5553 NR 20 TC 17 Z9 17 U1 0 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 11 PY 1999 VL 402 IS 6758 BP 157 EP 160 DI 10.1038/45990 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 256FZ UT WOS:000083716400041 ER PT J AU Appelshauser, H Bachler, J Bailey, SJ Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Billmeier, A Blyth, CO Bock, R Boimska, B Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Carr, LD Cebra, D Cooper, GE Cramer, JG Cristinziani, M Csata, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Geist, W Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Lednicky, R Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Prindle, DJ Puhlhofer, F Susa, T Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Sikler, F Skrzypczak, E Snellings, R Squier, GTA Stock, R Strobele, H Struck, C Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wood, L Xu, N Yates, TA Zimanyi, J Zhu, XZ Zybert, R AF Appelshauser, H Bachler, J Bailey, SJ Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Billmeier, A Blyth, CO Bock, R Boimska, B Bormann, C Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Carr, LD Cebra, D Cooper, GE Cramer, JG Cristinziani, M Csata, P Dunn, J Eckardt, V Eckhardt, F Ferguson, MI Fischer, HG Flierl, D Fodor, Z Foka, P Freund, P Friese, V Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Geist, W Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hummler, H Igo, G Irmscher, D Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Lednicky, R Levai, P Malakhov, AI Margetis, S Markert, C Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Petridis, A Piper, A Porter, RJ Poskanzer, AM Prindle, DJ Puhlhofer, F Susa, T Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Semenov, AY Schafer, E Schmischke, D Schmitz, N Schonfelder, S Seyboth, P Sikler, F Skrzypczak, E Snellings, R Squier, GTA Stock, R Strobele, H Struck, C Szentpetery, I Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Voloshin, S Vranic, D Wang, F Weerasundara, DD Wenig, S Whitten, C Wood, L Xu, N Yates, TA Zimanyi, J Zhu, XZ Zybert, R TI Two-proton correlations from 158 A GeV Pb+Pb central collisions SO PHYSICS LETTERS B LA English DT Article ID SMALL RELATIVE MOMENTA; HEAVY-ION COLLISIONS; NUCLEAR COLLISIONS; ULTRARELATIVISTIC ENERGIES; HADRONIC-INTERACTIONS; CERN SPS; INTERFEROMETRY; DEPENDENCE; DYNAMICS; MULTIPLICITY AB The two-proton correlation function at midrapidity from Pb + Pb central collisions at 158 A GeV has been measured by the NA49 experiment. The results are compared to model predictions from static thermal Gaussian proton source distributions and transport models rqmd and venus. An effective proton source size is determined by minimizing chi(2)/ndf between the correlation functions of the data and those calculated for the Gaussian sources, yielding sigma(eff) = 3.85 +/- 0.15(stat.)(-0.25)(+0.60)(syst.) fm. Both the rqmd and the venus model are consistent with the data within the error in the correlation peak region. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Inst Phys Nucl, Krakow, Poland. Gesellsch Schwerionenforsch GSI, Darmstadt, Germany. Univ Calif Davis, Davis, CA 95616 USA. Joint Nucl Res Inst, Dubna, Russia. Univ Frankfurt, Fachbereich Phys, D-6000 Frankfurt, Germany. Kent State Univ, Kent, OH 44242 USA. Univ Calif Los Angeles, Los Angeles, CA USA. Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Warsaw Univ, Inst Phys Expt, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Washington, Inst Phys Expt, Seattle, WA 98195 USA. Yale Univ, New Haven, CT USA. Rudjer Boskovic Inst, Zagreb, Croatia. Univ Athens, Dept Phys, Athens, Greece. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Birmingham, Birmingham, W Midlands, England. KFKI Res Inst Particle & Nucl Phys, Budapest, Hungary. CERN, Geneva, Switzerland. Inst Phys, Prague, Czech Republic. RP Appelshauser, H (reprint author), Univ Heidelberg, Inst Phys, Philosophenweg 12, D-6900 Heidelberg, Germany. RI Barnby, Lee/G-2135-2010; Voloshin, Sergei/I-4122-2013; Levai, Peter/A-1544-2014; Lednicky, Richard/K-4164-2013; Carr, Lincoln/E-3819-2016; OI Barnby, Lee/0000-0001-7357-9904; Carr, Lincoln/0000-0002-4848-7941; Cristinziani, Markus/0000-0003-3893-9171 NR 44 TC 25 Z9 26 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD NOV 11 PY 1999 VL 467 IS 1-2 BP 21 EP 28 DI 10.1016/S0370-2693(99)01152-1 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259TU UT WOS:000083910700004 ER PT J AU Catterall, S Mottola, E AF Catterall, S Mottola, E TI The conformal mode in 2D simplicial gravity SO PHYSICS LETTERS B LA English DT Article ID 4D QUANTUM-GRAVITY; RANDOM SURFACES; SCALAR CURVATURE; BOSONIC STRINGS; SECTOR; DIMENSIONS; GEOMETRY AB We verify that summing 2D DT geometries correctly reproduces the Polyakov action for the conformal mode, including all ghost contributions, at large volumes. The Gaussian action is reproduced even for c(m) = 10, well into the branched polymer phase, which confirms the expectation that the DT measure is indeed correct in this regime as well (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Syracuse Univ, Dept Phys, Syracuse, NY 13244 USA. Los Alamos Natl Lab, Theoret Div T8, Los Alamos, NM 87545 USA. RP Syracuse Univ, Dept Phys, Syracuse, NY 13244 USA. EM smc@suhep.phy.syr.edu; emil@lanl.gov OI Catterall, Simon/0000-0003-2735-2682 NR 32 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 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD NOV 11 PY 1999 VL 467 IS 1-2 BP 29 EP 39 DI 10.1016/S0370-2693(99)01053-9 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259TU UT WOS:000083910700005 ER PT J AU Wang, LQ Exarhos, GJ Liu, J AF Wang, LQ Exarhos, GJ Liu, J TI Nuclear magnetic resonance - Characterization of self-assembled nanostructured materials SO ADVANCED MATERIALS LA English DT Article ID MESOPOROUS MOLECULAR-SIEVES; STATE C-13 NMR; X-RAY; QUADRUPOLAR NUCLEI; DOUBLE-ROTOR; MONOLAYERS; SURFACTANT; SOLIDS; ANGLE; DYNAMICS AB Self-assembly has been widely used for the preparation of novel nanostructured materials. To both accelerate the dynamics of this processing route and develop new nanostructures, it is critical to understand the attendant interfacial interactions that occur in solution between the different precursor components, and how such molecular level interactions affect nanostructured ordering. Extensive discussions of experimental techniques for characterizing nanoscale materials, such as small-angle X-ray or neutron scattering, high-resolution electron microscopy, and surface force microscopy can be found elsewhere.([l]) This review will focus on nuclear magnetic resonance (NMR) methods, which are sensitive to local chemical environments and provide complementary information on the molecular scale, in contrast to other analytical techniques. The first section provides a brief introduction to fundamental NMR principles and their applications. It is followed by examples to illustrate how NMR can be used to derive information related to long-range ordering on the nanometer scale, the molecular conformation on a sub-nanometer scale, and their correlation to interfacial binding. C1 Pacific NW Lab, Dept Mat, Richland, WA 99352 USA. RP Liu, J (reprint author), Pacific NW Lab, Dept Mat, MSIN K2-44,Battelle Blvd, Richland, WA 99352 USA. NR 67 TC 24 Z9 24 U1 0 U2 6 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD NOV 10 PY 1999 VL 11 IS 16 BP 1331 EP 1341 DI 10.1002/(SICI)1521-4095(199911)11:16<1331::AID-ADMA1331>3.0.CO;2-8 PG 11 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 255UF UT WOS:000083688000006 ER PT J AU Dillon, AC Gennett, T Jones, KM Alleman, JL Parilla, PA Heben, MJ AF Dillon, AC Gennett, T Jones, KM Alleman, JL Parilla, PA Heben, MJ TI A simple and complete purification of single-walled carbon nanotube materials SO ADVANCED MATERIALS LA English DT Article ID VIBRATIONAL-MODES; RAMAN-SCATTERING; SPECTROSCOPY C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Heben, MJ (reprint author), Natl Renewable Energy Lab, 167 Cole Blvd, Golden, CO 80401 USA. NR 15 TC 422 Z9 433 U1 17 U2 128 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD NOV 10 PY 1999 VL 11 IS 16 BP 1354 EP 1358 DI 10.1002/(SICI)1521-4095(199911)11:16<1354::AID-ADMA1354>3.0.CO;2-N PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 255UF UT WOS:000083688000010 ER PT J AU Frenk, CS White, SDM Bode, P Bond, JR Bryan, GL Cen, R Couchman, HMP Evrard, AE Gnedin, N Jenkins, A Khokhlov, AM Klypin, A Navarro, JF Norman, ML Ostriker, JP Owen, JM Pearce, FR Pen, UL Steinmetz, M Thomas, PA Villumsen, JV Wadsley, JW Warrren, MS Xu, G Yepes, G AF Frenk, CS White, SDM Bode, P Bond, JR Bryan, GL Cen, R Couchman, HMP Evrard, AE Gnedin, N Jenkins, A Khokhlov, AM Klypin, A Navarro, JF Norman, ML Ostriker, JP Owen, JM Pearce, FR Pen, UL Steinmetz, M Thomas, PA Villumsen, JV Wadsley, JW Warrren, MS Xu, G Yepes, G TI The Santa Barbara cluster comparison project: A comparison of cosmological hydrodynamics solutions SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; dark matter; galaxies : clusters : general; large-scale structure of universe; X-rays : galaxies ID SMOOTHED PARTICLE HYDRODYNAMICS; X-RAY-CLUSTERS; FLUX-CORRECTED TRANSPORT; HIGH-RESOLUTION; GALAXY CLUSTERS; GAS-DYNAMICS; N-BODY; UNIVERSE; SIMULATION; ALGORITHM AB We have simulated the formation of an X-ray cluster in a cold dark matter universe using 12 different codes. The codes span the range of numerical techniques and implementations currently in use, including smoothed particle hydrodynamics (SPH) and grid methods with fixed, deformable, or multilevel meshes. The goal of this comparison is to assess the reliability of cosmological gasdynamical simulations of clusters in the simplest astrophysically relevant case, that in which the gas is assumed to be nonradiative. We compare images of the cluster at different epochs, global properties such as mass, temperature and X-ray luminosity, and radial profiles of various dynamical and thermodynamical quantities. On the whole, the agreement among the various simulations is gratifying, although a number of discrepancies exist. Agreement is best for properties of the dark matter and worst for the total X-ray luminosity. Even in this case, simulations that adequately resolve the core radius of the gas distribution predict total X-ray luminosities that agree to within a factor of 2. Other quantities are reproduced to much higher accuracy. For example, the temperature and gas mass fraction within the virial radius agree to within about 10%, and the ratio of specific dark matter kinetic to gas thermal energies agree to within about 5%. Various factors, including differences in the internal timing of the simulations, contribute to the spread in calculated cluster properties. Based on the overall consistency of results, we discuss a number of general properties of the cluster we have modeled. C1 Univ Durham, Dept Phys, Durham DH1 3LE, England. Max Planck Inst Astrophys, D-85740 Garching, Germany. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Toronto, Dept Astron, Toronto, ON M5S 3H8, Canada. MIT, Dept Phys, Cambridge, MA 02139 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. USN, Res Lab, Computat Phys & Fluid Dynam Lab, Washington, DC 20375 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88001 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 2P6, Canada. Univ Illinois, NCSA, Lab Computat Astrophys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Sussex, Brighton BN1 9QH, E Sussex, England. Univ Calif Santa Cruz, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Autonoma Madrid, Dept Fis Teor 100 11, E-28049 Madrid, Spain. RP Univ Durham, Dept Phys, Durham DH1 3LE, England. RI Pearce, Frazer/H-1503-2012; OI Warren, Michael/0000-0002-1218-7904; Evrard, August/0000-0002-4876-956X; Yepes, Gustavo/0000-0001-5031-7936; Thomas, Peter/0000-0001-6888-6483 NR 56 TC 344 Z9 346 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 1999 VL 525 IS 2 BP 554 EP 582 DI 10.1086/307908 PN 1 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 257HP UT WOS:000083776700002 ER PT J AU Sako, M Liedahl, DA Kahn, SM Paerels, F AF Sako, M Liedahl, DA Kahn, SM Paerels, F TI The X-ray spectrum and global structure of the stellar wind in Vela X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; pulsars : individual (Vela X-1); stars : neutron; stars : winds, outflows; X-rays : stars ID RADIATION-DRIVEN WINDS; CROSS-SECTIONS; LINE EMISSION; CIRCUMSTELLAR MATTER; ABSORPTION-SPECTRUM; HOT STARS; ACCRETION; BINARY; MASS; ULTRAVIOLET AB We present a quantitative analysis of the X-ray spectrum of the eclipsing high mass X-ray binary Vela X-1 (4U 0900-40) using archival data from the ASCA Solid-State Imaging Spectrometer. The observation covers a time interval centered on the eclipse of the X-ray pulsar by the companion. The spectrum exhibits two distinct sets of discrete features: (1) recombination lines and radiative recombination continua from mostly hydrogenic and helium-like species produced by photoionization in an extended stellar wind; and (2) fluorescent K-shell lines associated with near-neutral species also present in the circumsource medium. These features are superposed on a faint continuum, which is most likely nonthermal emission from the accreting neutron star that is scattered into our line of sight by free electrons in the wind. Using a detailed spectral model that explicitly accounts for the recombination cascade kinetics for each of the constituent charge states, we are able to obtain a statistically acceptable (chi(r)(2) = 0.88) fit to the observed spectrum and to derive emission measures associated with the individual K-shell ions of several elements. From calculations of the ionization balance using the photoionization code, XSTAR, we assign ionization parameters, xi, to several ions, and construct a differential emission measure (DEM) distribution. The DEM distribution spans a broad range in xi (Delta log xi greater than or similar to 2) and is centered around log xi = 2.5. We find that the total emission measure of the visible portion of the highly ionized wind is similar to 3 x 10(56) cm(-3). The qualitative aspects of the inferred DEM distribution are consistent with a wind model derived from the Hatchett & McCray picture of an X-ray source immersed in a stellar wind with a generalized Castor, Abbott, & Klein velocity profile. Using this formalism, theoretical DEM distributions, parameterized only by a mass-loss rate and a wind velocity profile, are calculated and used to predict the detailed X-ray spectrum, which is then compared to the ASCA data. Again, we find a statistically acceptable fit (chi(r)(2) = 1.01), with a best-fit mass-loss rate of similar to 2.7 x 10(-7) M. yr(-1). This is approximately a factor of 10 lower than previous estimates of the mass-loss rate for the Vela X-1 companion star, which have primarily been determined from C IV and Si IV P Cygni profiles, and X-ray absorption measurements. We argue that this discrepancy can be reconciled if the X-ray-irradiated portion of the wind in Vela X-1 is structurally inhomogeneous, consisting of hundreds of cool, dense clumps embedded in a hotter, more ionized gas. Most of the mass is contained in the clumps, while most of the wind volume (>95%) is occupied by the highly ionized component. We show quantitatively that this interpretation is also consistent with the presence of the X-ray fluorescent lines in the ASCA spectrum, which are produced in the cooler, clumped component. C1 Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. RP Sako, M (reprint author), Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. NR 62 TC 82 Z9 82 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 1999 VL 525 IS 2 BP 921 EP 934 DI 10.1086/307924 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 257HP UT WOS:000083776700037 ER PT J AU Bell, AT AF Bell, AT TI NMR applied to zeolite synthesis SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article; Proceedings Paper CT VIIIth International Symposium in Colloid and Interface Sciences CY MAY 24-29, 1998 CL NAMUR, BELGIUM SP Natl Rech Sci, Region Wallonne, Minist Comm Francaise, Fac Univ Notre Dame Paix, Bruker, Exxon Chem Europe Inc, Solvay, Procter & Gambler, Vel & New DE NMR; zeolite synthesis ID ALUMINOSILICATE SOLUTIONS; SILICATE; ANIONS; MECHANISM; RATIO AB Zeolites are synthesized from highly alkaline aluminosilicate gels. The structure of the gel and the connectivity of the Si and Al atoms in both the solid and liquid portions of the gel can be probed by NMR. Results are presented showing the applications of Si-29 MAS NMR to study the transformations occurring during the synthesis of NaY zeolite and the purely siliceous form of ZSM-5, known as silicalite. Structure directing tetrapropylammonium (TPA(+)) cations are required for the synthesis of silicalite. It is demonstrated that H-1-Si-29 and H-1-C-13 CP MAS NMR provide information about the relationship of the TPA(+) cations to the siliceous portions of the synthesis gel and about the conformation of the propyl groups of the cation. The use of liquid-line Si-29 and Al-27 NMR to identify the composition and structure of silicate and aluminosilicate species in TPA silicate and aluminosilicate solutions is illustrated as well. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Div Chem Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Bell, AT (reprint author), Univ Calif Berkeley, Div Chem Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. EM bell@cchem.berkeley.edu OI Bell, Alexis/0000-0002-5738-4645 NR 19 TC 13 Z9 13 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 EI 1873-4359 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD NOV 10 PY 1999 VL 158 IS 1-2 BP 221 EP 234 DI 10.1016/S0927-7757(99)00149-1 PG 14 WC Chemistry, Physical SC Chemistry GA 257HM UT WOS:000083776500029 ER PT J AU McLemore, DK Dixon, DA Strauss, SH AF McLemore, DK Dixon, DA Strauss, SH TI Density functional theory and fluorocarboranes I. Trends in B-H and B-F distances and dissociation energies for CB11H12-nFn- anions (n=0, 1, 6, 11) SO INORGANICA CHIMICA ACTA LA English DT Article DE fluorocarborane; density functional theory; dissociation energies ID WEAKLY COORDINATING ANIONS; CARBORANE ANIONS; METAL CLUSTERS; BORON; FLUORINATION; ELECTROPHILES; CHEMISTRY; C2BN-2HN; BORANES; CB9H10 AB Density functional theory (DFT) methods have been used to predict the geometries and a variety of energetic quantities of fluorinated closo-monocarborane clusters. Geometries were optimized at the local DFT level and energetics obtained at the gradient-corrected level. The species studied were CB11H12- 2-, 7-, and 12-CB11H11F-, 7,8,9,10,11,12-CB11H6F6- (CB11H6F6-), 1-H-CB11F11- and fragments of the parent anion obtained by removing an H atom or an H- ion from a given cluster vertex. For the anions CB11H12-, 12-CB11H11F-, CB11H6F6- and 1-H-CB11F11- the optimized CB11 cores were icosahedral cages with C-5p symmetry. The predicted C-B, B-B, C-H, B-H, and B-F bond distances are in good agreement with available experimental data and, in the case of CB11H12-, with bond distances predicted at the MP2 or Hartree-Fock levels of theory. The calculations show that dissociation of H- from CB11H12- or F- from CB11H11F- varies by more than 12 kcal mol(-1) depending on which type of boron vertex is chosen (the dissociations are most endothermic for upper-belt B-H and B-F bonds). In contrast, the dissociation of H or F atoms varies by less than 2 kcal mol(-1) for the three types of boron vertices. The calculations predict that 2-CB11H11F- marginally more stable than 7-CB11H11F- or 12-CB11H11F- (the relative energies are 0, 0.91, and 0.17 kcal mol(-1), respectively), despite the observation that 12-CB11H11F- is the only isomer formed when CB11H12- is treated with liquid anhydrous HF. Therefore, the DFT results suggest that regioselective fluorination of CB11H12- under the conditions that have been used is under kinetic control. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. Pacific NW Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. EM strauss@chem.colostate.edu NR 47 TC 17 Z9 17 U1 1 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 EI 1873-3255 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD NOV 10 PY 1999 VL 294 IS 2 BP 193 EP 199 DI 10.1016/S0020-1693(99)00285-6 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 253QZ UT WOS:000083568400010 ER PT J AU Huhmann-Vincent, J Scott, BL Kubas, GJ AF Huhmann-Vincent, J Scott, BL Kubas, GJ TI Reactions of H-2, silanes, and olefins with superelectrophilic cationic rhenium complexes: heterolytic cleavage of H-2 and relation to the structure and function of hydrogenases SO INORGANICA CHIMICA ACTA LA English DT Article DE crystal structures; rhenium complexes; silane complexes; dihydrogen complexes; olefin complexes ID METAL DIHYDROGEN COMPLEXES; RAY CRYSTAL-STRUCTURE; MOLECULAR-HYDROGEN; H-H; TRANSITION-METALS; SIGMA-BOND; LIGAND; REACTIVITY; ACTIVATION; COORDINATION AB The reaction of cis-Re(CO)(4)(PR3)Me (R = Ph, Cy) with the Lewis acid B(C6F5)(3) was studied by NMR spectroscopy, and was found to provide an equilibrium mixture of the solvent-coordinated complex [cis-Re(CO)(4)(PR3)(ClCH2Cl)][MeB(C6F5)(3)] and the reactants. Reaction of cis-Re(CO)(4)(PR3)Me with HX (X = H, SiEt3) in the presence of B(C6F5)(3) at low temperature yielded the sigma-bonded complexes [cis-Re(CO)(4)(PR3)(eta(2)-HX)][MeB(C6F5)(3)] which decomposed at room temperature via intramolecular heterolytic cleavage of the X-H bond to produce MeX and the hydride-bridged dimer [cis-Re(CO)(4)(PR3)](2)(mu-H){MeB(C6F5)(3)}. The unstable H-2 binding and cleavage on this and other highly electrophilic organometallic complexes that contain strong a-acceptor CO ligands can be related to the structure and function of metalloenzymes such as Fe-containing hydrogenases that catalyze H-2 <--> H+ + 2e(-). The latter contain dinuclear organometallic-like active sites with CO ligands, which would promote binding and heterolytic cleavage of molecular H-2 in biological systems. The Fe-Fe and Ni-Fe bonds in hydrogenases are likely sites for protonation to form a bridging hydride as the initial step in the mechanism of H, formation, and electrophilic fragments such as [Re(CO)(4)(L)](+) strongly prefer to form bridging rather than terminal hydrides. The reaction of olefins and Et3SiH with the [cis-Re(Co)(4)(PR3)(ClCH2Cl)][BArF] (BArF = B[3,5-(CF3)(2)(C6H3)(4)(-)]) system was also investigated, and the X-ray crystal structure of the dimer {[cis -Re(CO)(4)(PPh3)](2)(mu-H)}{BArF} was determined. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Kubas, GJ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 95 TC 54 Z9 54 U1 0 U2 2 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 NOV 10 PY 1999 VL 294 IS 2 BP 240 EP 254 DI 10.1016/S0020-1693(99)00243-1 PG 15 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 253QZ UT WOS:000083568400016 ER PT J AU Brozik, JA Scott, BL Swanson, BI AF Brozik, JA Scott, BL Swanson, BI TI Synthetic control of intrinsic ground-state defects in a mixed valence quasi-one-dimensional Pt halide chain SO INORGANICA CHIMICA ACTA LA English DT Article DE platinum complexes; quasi-one-dimensional chain; hydrogen bonding interactions; charge density wave ID PHOTOINDUCED DEFECTS; PLATINUM COMPLEXES AB The new linear chain compound [Pt(en)(2)Cl-2][Pt(en)(2)][Pt(CN)(4)](2) has been synthesized through two independent methods to yield a quasi-one-dimensional chain with very strong hydrogen bonding interactions. The high charge density wave (CDW) character will be discussed in terms of an unusual hydrogen bonding network which bridges adjacent chains but does not bridge adjacent oxidized and reduced units within a chain. Such a network is unique and breaks from known CDW trends derived from the template effect. The results of the structural analysis by X-ray crystallography have shown that the chains grown from two independent methods are isostructural with one another. Spectroscopic results (resonance Raman and diffuse reflectance) clearly demonstrate the presence of ground-state polaronic defects in crystals grown from solution of stoichiometric amounts of subunits while crystals grown from Pt(IV) rich solutions display a complete absence of ground-state polaronic signatures. These results will be discussed in terms of how one can chemically control the presence and amount of ground-state reduced site defects in the general class of MX materials. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Swanson, BI (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 17 TC 15 Z9 15 U1 0 U2 0 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 NOV 10 PY 1999 VL 294 IS 2 BP 275 EP 280 DI 10.1016/S0020-1693(99)00275-3 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 253QZ UT WOS:000083568400019 ER PT J AU Wenk, HR Tome, CN AF Wenk, HR Tome, CN TI Modeling dynamic recrystallization of olivine aggregates deformed in simple shear SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID HIGH-TEMPERATURE CREEP; UPPER MANTLE ANISOTROPY; PREFERRED ORIENTATION; PLASTIC-DEFORMATION; FABRIC DEVELOPMENT; SINGLE-CRYSTALS; POLYCRYSTALLINE ICE; TEXTURE DEVELOPMENT; FLOW; LHERZOLITES AB Experiments by Zhang and Karato [1995] have shown that in simple shear dislocation creep of olivine at low strains, an asymmetric texture develops with a [100] maximum rotated away from the shear direction against the sense of shear. At large strain where recrystallization is pervasive, the texture pattern is symmetrical, and [100] is parallel to the shear direction. The deformation texture can be adequately modeled with a viscoplastic self-consistent polycrystal plasticity theory. This model can be expanded to include recrystallization, treating the process as a balance of boundary migration (growth of relatively underformed grains at the expense of highly deformed grains) and nucleation (strain-free nuclei replacing highly deformed grains). If nucleation dominates over growth, the model predicts a change from the asymmetric to the symmetric texture as recrystallization proceeds and stabilization in the "easy slip" orientation for the dominant (010)[100] slip system. This result is in accordance with the experiments and suggests that the most highly deformed orientation components dominate the recrystallization texture. The empirical model will be useful to simulate more adequately the development of anisotropy in the mantle where olivine is largely recrystallized. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Wenk, HR (reprint author), Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. EM wenk@seismo.berkeley.edu; tome@lanl.gov RI Tome, Carlos/D-5058-2013 NR 70 TC 67 Z9 67 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD NOV 10 PY 1999 VL 104 IS B11 BP 25513 EP 25527 DI 10.1029/1999JB900261 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 255DE UT WOS:000083653600023 ER PT J AU Musgrave, KB Donahue, JP Lorber, C Holm, RH Hedman, B Hodgson, KO AF Musgrave, KB Donahue, JP Lorber, C Holm, RH Hedman, B Hodgson, KO TI An X-ray spectroscopic investigation of bis(dithiolene)molybdenum(IV,V,VI) and -tungsten(IV,V,VI) complexes: Symmetrized structural representations of the active sites of molybdoenzymes in the DMSO reductase family and of tungstoenzymes in the AOR and F(M)DH families SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DIMETHYL-SULFOXIDE REDUCTASE; OXYGEN-ATOM TRANSFER; ALDEHYDE FERREDOXIN OXIDOREDUCTASE; BODY DISTRIBUTION-FUNCTIONS; ABSORPTION-SPECTROSCOPY; CRYSTAL-STRUCTURE; RHODOBACTER-SPHAEROIDES; MOLYBDENUM-COFACTOR; ESCHERICHIA-COLI; FORMATE DEHYDROGENASE AB Molybdenum and tungsten oxotransferase and hydroxylase enzymes catalyze the generalized reaction X + H2O <----> XO + 2H(+) + 2e(-) involving substrate and product X/XO. All such enzymes contain one or two pterin dithiolene ligands bound to a molybdenum or tungsten atom in the enzyme cofactor. Recent investigations in these laboratories together with earlier work by others have afforded a set of 10 complexes, all structurally characterized by X-ray diffraction, that are relevant to the active sites of several families of enzymes containing two pterin dithiolenes: [(MO)-O-IV(bdt)(2)](2-) (1, 6), [M-V(bdt)(2)](1-) (2, 7), [M-IV((OSiBuPh2)-Ph-t)(bdt)(2)](1-) (3, 8), [(MO2)-O-VI(bdt)(2)](2-) (4, 9), and [(MO)-O-VI((OSiBuPh2)-Ph-t)(bdt)(2)](1-) (5, 10) [M = Mo (1-5), W (6-10); bdt = benzene-1,2-dithiolate(2-)]. In particular, complexes 3 and 5 simulate the reduced and oxidized sites, respectively, of one DMSO reductase. This set of complexes of accurately known structure provides a heretofore unavailable opportunity to examine by X-ray absorption spectroscopy (XAS) the effects of different oxidation states, ligand types, and coordination geometries on absorption edge and EXAFS features. Molybdenum K-edge or tungsten L-2,L-3-edge spectra and EXAFS analysis (using the GNXAS protocol) are reported for 1-10. Systematic shifts of edge energies over the M(IV,V,VI) oxidation states are observed, and features in the second derivative edge spectra are correlated with the number (0-2) of oxo ligands. While the field of molybdenum and tungsten enzymes has been substantially advanced by protein crystallography, there exist variances in metal-dithiolene interactions for a given enzyme and structural differences among closely related enzymes. Further, protein crystallographic results are not always consistent with conclusions from XAS and other spectroscopic studies. These molecules serve as benchmarks or calibrants with respect to the corresponding structural properties of enzyme sites containing two pterin dithiolene cofactor ligands and one br two oxygen-based ligands such as members of the DMSO family of molybdoenzymes and the AOR and F(M)DH families of tungstoenzymes. Because of the internal consistency of EXAFS and X-ray crystallography results, these complexes will prove useful for future comparisons with enzymes of both known and unknown structure and may help to clarify discrepancies seen in protein crystallography. C1 Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Holm, RH (reprint author), Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. RI Lorber, Christian/G-5490-2012 OI Lorber, Christian/0000-0003-1361-5373 NR 49 TC 38 Z9 38 U1 2 U2 10 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 NOV 10 PY 1999 VL 121 IS 44 BP 10297 EP 10307 DI 10.1021/ja990753p PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 256HL UT WOS:000083719800006 ER PT J AU Tsai, YC Johnson, MJA Mindiola, DJ Cummins, CC Klooster, WT Koetzle, TF AF Tsai, YC Johnson, MJA Mindiola, DJ Cummins, CC Klooster, WT Koetzle, TF TI A cyclometalated resting state for a reactive molybdenum amide: Favorable consequences of beta-hydrogen elimination including reductive cleavage, coupling, and complexation SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID 3-COORDINATE MOLYBDENUM(III); NITRIDO COMPLEXES; TRIPLE BONDS; ACETONITRILE; DINITROGEN; TANTALUM; NIOBIUM; DERIVATIVES; COMPOUND; CRYSTAL C1 MIT, Dept Chem, Cambridge, MA 02139 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Cummins, CC (reprint author), MIT, Dept Chem, Room 2-227, Cambridge, MA 02139 USA. RI Cummins, Christopher/J-2961-2014 OI Cummins, Christopher/0000-0003-2568-3269 NR 22 TC 98 Z9 98 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD NOV 10 PY 1999 VL 121 IS 44 BP 10426 EP 10427 DI 10.1021/ja9917464 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 256HL UT WOS:000083719800026 ER PT J AU Dosa, PI Erben, C Iyer, VS Vollhardt, KPC Wasser, IM AF Dosa, PI Erben, C Iyer, VS Vollhardt, KPC Wasser, IM TI Metal encapsulating carbon nanostructures from oligoalkyne metal complexes SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SINGLE-WALLED NANOTUBES; CATALYTIC PYROLYSIS; CRYSTAL-STRUCTURE; GROWTH; HYDROCARBONS; FULLERENES; DECOMPOSITION; ISOMERIZATION; NANOPARTICLES; PRECURSORS C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Vollhardt, KPC (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 51 TC 93 Z9 94 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD NOV 10 PY 1999 VL 121 IS 44 BP 10430 EP 10431 DI 10.1021/ja9924602 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 256HL UT WOS:000083719800028 ER PT J AU Aytug, T Yu, Y Yan, SL Xie, YY Wu, JZ AF Aytug, T Yu, Y Yan, SL Xie, YY Wu, JZ TI Response of superconducting characteristics of Hg-based high-T-c thin films to photolithographic processes SO PHYSICA C LA English DT Article DE high-temperature superconductivity; Hg-1212; stability; photolithography ID AQUEOUS ENVIRONMENTS; TEMPERATURE; YBA2CU3O7-X; STABILITY; WATER; PHASE AB The stability of the properties of Hg-based superconducting thin films has been studied during conventional photolithographic patterning processes. The patterning process was divided into individual steps such as photoresist baking, developing and etching in order to observe the effect of each step separately on the superconducting properties of the samples. After baking of the photoresist, a considerable degradation in the superconducting properties was observed, while samples did not show any visible degradation after they were etched with acid solution. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RP Aytug, T (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 3115,Ms 6061,Bethel Valley Rd, Oak Ridge, TN 37831 USA. NR 20 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV 10 PY 1999 VL 325 IS 1-2 BP 56 EP 60 DI 10.1016/S0921-4534(99)00509-2 PG 5 WC Physics, Applied SC Physics GA 261LT UT WOS:000084011200009 ER PT J AU Ynzunza, RX Palomares, FJ Tober, ED Wang, Z Morais, J Denecke, R Daimon, H Chen, Y Hussain, Z Van Hove, MA Fadley, CS AF Ynzunza, RX Palomares, FJ Tober, ED Wang, Z Morais, J Denecke, R Daimon, H Chen, Y Hussain, Z Van Hove, MA Fadley, CS TI Structure determination for saturated(1 x 1) oxygen on W(110) from full solid angle photoelectron diffraction with chemical-state resolution SO SURFACE SCIENCE LA English DT Article DE electron-solid interactions, scattering, diffraction; low energy electron diffraction (LEED); low index single crystal surfaces; oxygen; photoelectron diffraction; surface structure, morphology, roughness, and topography; synchrotron radiation photoelectron spectroscopy; tungsten ID ENERGY-ELECTRON-DIFFRACTION; ADSORPTION; SURFACE AB The local atomic geometry of oxygen adsorbed in a stable one monolayer (1 x 1) structure on W(110) has been determined for the first time from full solid angle site-resolved photoelectron diffraction (PD). This structure also exhibits an additional (1 x 12) periodicity, but PD allows determination of the local structure within this periodicity. The data were obtained with a new beamline and experimental system at the Advanced Light Source. W 4f(7/2) spectra excited at kinetic energies of approximately 140 eV were resolved into bulk and 'oxide' components, with the latter corresponding to the first layer of tungsten atoms bound directly to three oxygen atoms each. Analyzing these data with multiple scattering theory and R-factor analysis shows that the oxygen atoms sit in pseudo-threefold hollow sites at a vertical distance of 0.91 +/- 0.05 Angstrom above the first tungsten layer, and with a lateral position shifted by 0.1 Angstrom along [<1(1)over bar>0] or [(1) over bar 10] directions and away from that yielding three equal bond distances. Future applications of this method to systems with large unit cells which make beam-in/beam-out diffraction analyses difficult and/or with a lack of long range order are thus suggested. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Ynzunza, RX (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008; Palomares, Francisco Javier/C-4605-2011; Morais, Jonder/E-5022-2013 OI Van Hove, Michel/0000-0002-8898-6921; Palomares, Francisco Javier/0000-0002-4768-2219; Morais, Jonder/0000-0002-4143-1208 NR 22 TC 15 Z9 15 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 NOV 10 PY 1999 VL 442 IS 1 BP 27 EP 35 DI 10.1016/S0039-6028(99)00787-6 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 255KU UT WOS:000083668700014 ER PT J AU Laurer, JH Khan, SA Spontak, RJ Satkowski, MM Grothaus, JT Smith, SD Lin, JS AF Laurer, JH Khan, SA Spontak, RJ Satkowski, MM Grothaus, JT Smith, SD Lin, JS TI Morphology and rheology of SIS and SEPS triblock copolymers in the presence of a midblock-selective solvent SO LANGMUIR LA English DT Article ID ANGLE X-RAY; THERMOPLASTIC ELASTOMER GELS; DIBLOCK COPOLYMER; BLOCK-COPOLYMER; NEUTRON-SCATTERING; COPOLYMER/HOMOPOLYMER BLENDS; MECHANICAL-PROPERTIES; THERMOREVERSIBLE GELS; PHASE-DIAGRAM; FUMED SILICA AB While numerous fundamental studies have sought to elucidate the effect of a parent homopolymer on the morphological characteristics and mechanical properties of microphase-ordered block copolymer blends, few comparable efforts have extended such studies to concentrated copolymer solutions in the presence of a low-molar-mass block-selective solvent. In this work, we investigate the microstructures that form in blends of a poly(styrene-block-isoprene-block-styrene) (SIS) triblock copolymer with a midblock-selective aliphatic mineral oil. To discern the influence of midblock/oil compatibility on blend morphology and properties, identical blends with a poly[styrene-block-(ethylene-alt-propylene)-block-styrene] (SEPS) copolymer, the hydrogenated variant of the SIS copolymer, have likewise been examined. The saturated midblock of the SEPS copolymer is responsible for the observed shifts in morphology stability limits and higher dynamic elastic sheer moduli relative to the SIS analogue. These results reveal that the morphologies and properties of such triblock copolymer/oil blends are sensitive to the chemical/statistical nature of the copolymer midblock and may be judiciously tailored to satisfy application-specific requirements. C1 N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. N Carolina State Univ, Dept Chem Engn, Raleigh, NC 27695 USA. Procter & Gamble Co, Corp Res Div, Cincinnati, OH 45239 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Spontak, RJ (reprint author), N Carolina State Univ, Dept Mat Sci & Engn, Box 7907, Raleigh, NC 27695 USA. NR 64 TC 57 Z9 57 U1 0 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD NOV 9 PY 1999 VL 15 IS 23 BP 7947 EP 7955 DI 10.1021/la981441n PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 255RU UT WOS:000083684600012 ER PT J AU Marek, T Szeles, C Suvegh, K Kiss, E Vertes, A Lynn, KG AF Marek, T Szeles, C Suvegh, K Kiss, E Vertes, A Lynn, KG TI Characterization of arachidate Langmuir-Blodgett films by variable energy positron beams SO LANGMUIR LA English DT Article ID X-RAY-DIFFRACTION; REFLECTION ABSORPTION-SPECTROSCOPY; CADMIUM ARACHIDATE; PHOTOELECTRON-SPECTROSCOPY; INFRARED-SPECTROSCOPY; ATTENUATION LENGTH; LEAD STEARATE; CD-ARACHIDATE; FATTY-ACIDS; MULTILAYER AB Arachidate Langmuir-Blodgett (LB) films of different chemical composition and number of monomolecular layers deposited on silylated silica glass substrates were studied by means of positron annihilation spectroscopy. The applied methods included the measurement of the Doppler broadening of the annihilation photopeak with variable energy positron beams and bulk positron lifetime measurements. The studied samples were 58 monomolecular layers (MML) thick Mg- and Cd-arachidate, arachidic acid (50 MML) and a series of Pb-arachidate samples with 4, 10, 20, 40, and 58 MML. The investigation showed that the variable energy positron beam technique is capable of measuring the thickness of the deposited LB films. The measured positron annihilation parameters are sensitive to the chemical composition of the films and the behavior of the films in a vacuum. The results confirmed the stability of salt base LB films in high vacuum conditions and showed the desorption of pure acid films. These investigations have also shown that a strong positron trap is formed in the near-surface region of the hydrophobized substrate as a consequence of the silylation process. The results suggest that positron beams provide valuable complementary information to results obtained by other techniques. C1 Brookhaven Natl Lab, Dept Mat Sci & Phys, Upton, NY 11973 USA. Eotvos Lorand Univ, Dept Nucl Chem, H-1518 Budapest, Hungary. Eotvos Lorand Univ, Dept Colloid Chem & Colloid Technol, H-1518 Budapest, Hungary. RP Brookhaven Natl Lab, Dept Mat Sci & Phys, Upton, NY 11973 USA. EM marek@para.chem.elte.hu RI Kiss, E/H-4455-2011; Marek, Tamas/A-7606-2012 OI Kiss, E/0000-0002-4757-4437; Marek, Tamas/0000-0001-6076-4289 NR 49 TC 14 Z9 14 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD NOV 9 PY 1999 VL 15 IS 23 BP 8189 EP 8196 DI 10.1021/la990109o PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 255RU UT WOS:000083684600045 ER PT J AU Chow, WW Jones, ED Modine, NA Allerman, AA Kurtz, SR AF Chow, WW Jones, ED Modine, NA Allerman, AA Kurtz, SR TI Laser gain and threshold properties in compressive-strained and lattice-matched GaInNAs/GaAs quantum wells SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR AB The optical gain spectra for compressive-strained and lattice-matched GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of lasing threshold current density for different GaInNAs/GaAs laser structures. (C) 1999 American Institute of Physics. [S0003-6951(99)05245-6]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Chow, WW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 72 Z9 72 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 NOV 8 PY 1999 VL 75 IS 19 BP 2891 EP 2893 DI 10.1063/1.125181 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900007 ER PT J AU Yan, Y Al-Jassim, MM Matsuda, K Tatsuoka, H Kuwabara, H Pennycook, SJ AF Yan, Y Al-Jassim, MM Matsuda, K Tatsuoka, H Kuwabara, H Pennycook, SJ TI The mechanism for the high-quality single-phase growth of MnSi films on Si (111) in the presence of Sb flux SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; DIFFUSION; CRYSTALS; SILICON AB The microstructures of high-quality single-phase MnSi layers grown on Si (111) by Mn deposition and reaction with Si in the presence of Sb flux are characterized by Z-contrast imaging. It is found that there is a transition layer consisting of two Sb monolayers sandwiching a Mn layer in between the Si substrate and the single-phase MnSi film. This Sb-Mn-Sb sandwich layer effectively prevents deposited Mn atoms from direct reaction with Si atoms in the substrate to form Mn silicides. This explains why high-quality single-phase MnSi layers can be grown with remarkably smooth interface on Si (111) substrates. (C) 1999 American Institute of Physics. [S0003-6951(99)01645-9]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Shizuoka Univ, Fac Engn, Hamamatsu, Shizuoka 4328561, Japan. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Yan, Y (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 21 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 8 PY 1999 VL 75 IS 19 BP 2894 EP 2896 DI 10.1063/1.125182 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900008 ER PT J AU Reboredo, FA Franceschetti, A Zunger, A AF Reboredo, FA Franceschetti, A Zunger, A TI Excitonic transitions and exchange splitting in Si quantum dots SO APPLIED PHYSICS LETTERS LA English DT Article ID NANOCRYSTALS; SILICON AB In a quantum dot made of an indirect gap material such as Si, the electron-hole Coulomb interaction alone can give rise to "dark" excitons even in the absence of exchange interaction. We present the predicted excitonic spectra for hydrogen-passivated Si dots and find very good agreement with the recent experiment of Wolkin, Jorne, Fauchet, Allan, and Delerue [Phys. Rev. Lett. 82, 197 (1999)]. The calculated splitting between dark and bright excitons, arising from Coulomb and exchange interactions, agrees very well with the optical data of Calcott, Nash, Canham, Kane, and Brumhead [J. Phys Condens. Matter 5, L91 (1993)]. (C) 1999 American Institute of Physics. [S0003-6951(99)04845-7]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Reboredo, FA (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Reboredo, Fernando/B-8391-2009; Zunger, Alex/A-6733-2013 NR 12 TC 31 Z9 31 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 8 PY 1999 VL 75 IS 19 BP 2972 EP 2974 DI 10.1063/1.125205 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900034 ER PT J AU Shen, J Swan, AK Wendelken, JF AF Shen, J Swan, AK Wendelken, JF TI Determination of critical thickness of spin reorientation in metastable magnetic ultrathin films SO APPLIED PHYSICS LETTERS LA English DT Article ID FCC CO(001) STRUCTURES; SURFACE ANISOTROPY; FE FILMS; CU(100); TEMPERATURE; INPLANE; FE/CU(100); DEPENDENCE; CU(001) AB We investigate the spin reorientation of structurally unstable magnetic ultrathin films (base films) using magnetic capping layers. The capping layers, whose effective anisotropy constant is opposite that of the base films, are grown on the base films with no transformed structure and induce a spin reorientation after exceeding a critical thickness. The critical thickness of the capping layers can be used to deduce the critical thickness as well as the anisotropy constants of the base films. We use Co to cap the well-known Fe/Cu(100) system as an example to demonstrate the proposed approach. (C) 1999 American Institute of Physics. [S0003-6951(99)02145-2]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Shen, J (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 20 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 8 PY 1999 VL 75 IS 19 BP 2987 EP 2989 DI 10.1063/1.125210 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900039 ER PT J AU Gao, C Duewer, F Xiang, XD AF Gao, C Duewer, F Xiang, XD TI Quantitative microwave evanescent microscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID SPATIAL-RESOLUTION; FORCE AB We have developed a scanning evanescent microwave microscope with shielded tip geometry allowing quantitative characterization of the electrical impedance of insulating and conducting materials. By modeling the tip-sample capacitance, quantitative estimates of the sample (both dielectric and conducting) electrical impedance (real and imaginary) and tip-sample separation can be made. Measurements of the tip-sample capacitance versus tip-sample separation have been made and agree with estimated values. Also, the slope of the tip-sample capacitance with respect to the tip-sample distance is calculated to implement tip-sample distance regulation for dielectric materials. (C) 1999 American Institute of Physics. [S0003-6951(99)04245-X]. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Xiang, XD (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Xiang, Xiaodong/A-9445-2012; Xiang, Xiaodong/A-5936-2017 NR 16 TC 39 Z9 42 U1 1 U2 6 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 NOV 8 PY 1999 VL 75 IS 19 BP 3005 EP 3007 DI 10.1063/1.125216 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900045 ER PT J AU Fischer, AJ Choquette, KD Chow, WW Hou, HQ Geib, KM AF Fischer, AJ Choquette, KD Chow, WW Hou, HQ Geib, KM TI Coupled resonator vertical-cavity laser diode SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR MICROCAVITY; EMISSION AB We report the operation of an electrically injected monolithic coupled resonator vertical-cavity laser which consists of an active cavity containing InxGa1-xAs quantum wells optically coupled to a passive GaAs cavity. This device demonstrates modulation characteristics arising from dynamic changes in the coupling between the active and passive cavities. A composite mode theory is used to model the output modulation of the coupled resonator vertical-cavity laser. It is shown that the laser intensity can be modulated by either forward or reverse biasing the passive cavity. Under forward biasing, the modulation is due to carrier induced changes in the refractive index, while for reverse bias operation the modulation is caused by field dependent cavity enhanced absorption. (C) 1999 American Institute of Physics. [S0003-6951(99)03445-2]. C1 Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, Albuquerque, NM 87185 USA. RP Fischer, AJ (reprint author), Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, POB 5800, Albuquerque, NM 87185 USA. NR 12 TC 36 Z9 36 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 NOV 8 PY 1999 VL 75 IS 19 BP 3020 EP 3022 DI 10.1063/1.125220 PG 3 WC Physics, Applied SC Physics GA 252CV UT WOS:000083483900050 ER PT J AU Weitzel, KM Malow, M Jarvis, GK Baer, T Song, Y Ng, CY AF Weitzel, KM Malow, M Jarvis, GK Baer, T Song, Y Ng, CY TI High-resolution pulsed field ionization photoelectron-photoion coincidence study of CH4: Accurate 0 K dissociation threshold for CH3+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID METHANE; METHYL AB The formation of methyl cation (CH3+) from methane (CH4) has been investigated in high resolution using the newly perfected pulsed field ionization photoelectron-photoion coincidence (PFI-PEPICO) scheme. The PFI-PEPICO data reveal that fragmentation of CH4 in high-n Rydberg states occurs at energies above the dissociation threshold prior to pulsed field ionization. The crossover point of the breakdown curves is found to depend strongly on the Stark field in the ion source and thus traditional simulation procedures based on such a feature for ion dissociation energy determination are not appropriate in PFI-PEPICO studies. We show that for a prompt dissociation process, the disappearance energy of the parent molecule provides an accurate measure of the 0 K ion dissociation threshold, as that for CH3+ from CH4 is 14.323+/-0.001 eV. (C) 1999 American Institute of Physics. [S0021-9606(99)01742-0]. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Free Univ Berlin, Inst Chem Phys & Theoret Chem, D-14195 Berlin, Germany. RP Ng, CY (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. NR 18 TC 75 Z9 75 U1 2 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 NOV 8 PY 1999 VL 111 IS 18 BP 8267 EP 8270 DI 10.1063/1.480169 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 249RB UT WOS:000083345100002 ER PT J AU Li, X Wang, LS AF Li, X Wang, LS TI Electronic structure and chemical bonding between the first row transition metals and C-2: A photoelectron spectroscopy study of MC2- (M=Sc, V, Cr, Mn, Fe, and Co) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THERMODYNAMIC PROPERTIES; CARBON CLUSTERS; GROWTH; METALLOCARBOHEDRENES; CARBIDES; FULLERENES; NANOTUBES; CHROMIUM; STATES; ATOMS AB Vibrationally resolved photoelectron spectra of MC2- (M=Sc, V, Cr, Mn, Fe, and Co) are reported at two detachment photon energies, 532 and 355 nm. All the spectra showed a well resolved vibrational progression in the ground state detachment features. Electron affinities, vibrational frequencies, and information about the low-lying electronic states were obtained for the first row transition metal dicarbide molecules. The measured electron affinities for the MC2 species show strong metal-dependence with a minimum at VC2 and a maximum at MnC2. The ground state vibrational frequencies were observed to decrease from ScC2 to a minimum in CrC2 and then increases slightly in MnC2 and FeC2. The trends of the electron affinities and vibrational frequencies for the MC2 species were found to correlate well with the corresponding monoxides, suggesting that the chemical bonding in M-C-2 is analogous to that in M-O. The M-C-2 bonding was thus interpreted to be quite ionic, and MC2 can be qualitatively viewed as M2+ C-2(2-), analogous to M2+O2-. (C) 1999 American Institute of Physics. [S0021-9606(99)00742-4]. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. NR 40 TC 91 Z9 94 U1 1 U2 26 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 NOV 8 PY 1999 VL 111 IS 18 BP 8389 EP 8395 DI 10.1063/1.480218 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 249RB UT WOS:000083345100016 ER PT J AU Tan, HS Yoshikawa, A Gordon, MS Espenson, JH AF Tan, HS Yoshikawa, A Gordon, MS Espenson, JH TI Experimental and theoretical study of oxygen insertion into trialkylsilanes by methyltrioxorhenium catalyst SO ORGANOMETALLICS LA English DT Article ID METHYLRHENIUM TRIOXIDE; COMPLEXES; MECHANISM; OXIDATION; PEROXIDE; OXO AB Among the reactions of hydrogen peroxide that are catalyzed by methyltrioxorhenium, the oxidation of alkylsilanes is unique. It is not a reaction in which an oxygen atom is added to a substrate, but one featuring a net insertion, R3Si-H + H2O2 --> R3Si-OH + H2O. Kinetics studies were carried out on 10 compounds. Rate constant were determined far the bimolecular reaction of the silane with the peroxo compound CH3Re(O)(eta(2)-O-2)(2)(H2O). The variation of rate constant with the alkyl groups R follows two trends: the values of log(k) are linear functions of(a) the stretching frequency of the Si-H group and (b) the total Taft constant for these substituents. The reactions of (n-Bu)(3)Si-H and (n-Bu)(3)Si-D exhibit a kinetic isotope effect of 2.1 at 0 degrees C. From these data, a model for the transition state was formulated in which O-H and Si-O bond making accompany Si-H bond breaking. Quantum mechanical calculations have been carried out on the gas-phase reaction between Et3SiH and CH3Re(O)(2)(eta(2)-O-2). These results support this structure, calculating a structure and energy that are in agreement. The theoretical activation energy is 28.5 kcal mol(-1), twice the experimental value in aqueous acetonitrile, 12.4 kcal mol(-1). The difference can be attributed to the salvation of the polar transition state in this medium. C1 Univ Iowa, Ames Lab, Ames, IA 50011 USA. Univ Iowa, Dept Chem, Ames, IA 50011 USA. RP Gordon, MS (reprint author), Univ Iowa, Ames Lab, Ames, IA 50011 USA. NR 19 TC 17 Z9 18 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD NOV 8 PY 1999 VL 18 IS 23 BP 4753 EP 4757 DI 10.1021/om990579d PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 256PT UT WOS:000083734700012 ER PT J AU Beenakker, W Klasen, M Kramer, M Plehn, T Spira, M Zerwas, PM AF Beenakker, W Klasen, M Kramer, M Plehn, T Spira, M Zerwas, PM TI Production of charginos, neutralinos, and sleptons at hadron colliders SO PHYSICAL REVIEW LETTERS LA English DT Article ID FERMILAB TEVATRON; PAIR PRODUCTION; CROSS-SECTIONS; SUPERSYMMETRY; SEARCH; COLLISIONS; RESUMMATION; PHYSICS; SQUARK; QCD AB We analyze the production of charginos, neutralinos, and sleptons at the hadron colliders Tevatron and LHC in the direct channels p (p) over bar/pp --> <(chi)over tilde>(i)<(chi)over tilde>(j) + X and (l) over bar (l) over bar' + X. The cross sections for these reactions are given in next-to-leading order supersymmetric QCD. By including the higher-order corrections, the predictions become theoretically stable, being nearly independent of the factorization and renormalization scales. Since the corrections increase the cross sections, the discovery range for these particles is extended in the refined analysis. C1 Univ Durham, Dept Phys, Durham DH1 3LE, England. Argonne Natl Lab, Argonne, IL 60439 USA. CERN, Div Theoret Phys, CH-1211 Geneva, Switzerland. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Hamburg, Inst Theoret Phys 2, D-22603 Hamburg, Germany. Deutsch Elektronen Synchrotron, D-22603 Hamburg, Germany. RP Beenakker, W (reprint author), Univ Durham, Dept Phys, Durham DH1 3LE, England. NR 33 TC 207 Z9 207 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 NOV 8 PY 1999 VL 83 IS 19 BP 3780 EP 3783 DI 10.1103/PhysRevLett.83.3780 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200009 ER PT J AU Shaing, KC Aydemir, AY Hiwatari, R Houlberg, WA Ogawa, Y Zarnstorff, MC AF Shaing, KC Aydemir, AY Hiwatari, R Houlberg, WA Ogawa, Y Zarnstorff, MC TI Bifurcation and relaxation of radial electric field in enhanced reversed shear tokamak plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID POLOIDAL ROTATION; W7-AS STELLARATOR; CONFINEMENT; DISCHARGES; TRANSITION; TFTR; MODE AB It is shown that toroidal magnetic field ripple induced thermal and fast ion loss can drive the radial electric field to bifurcate over the local maximum of the parallel (or poloidal) viscosity. The subsequent plasma profile evolution reduces the hot particle density and relaxes the radial electric field. This behavior is consistent with the experimental observations in enhanced reversed shear mode in tokamaks. C1 Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. Univ Tokyo, Sch Engn, Tokyo, Japan. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Shaing, KC (reprint author), Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. OI Hiwatari, Ryoji/0000-0001-7201-4311 NR 26 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 8 PY 1999 VL 83 IS 19 BP 3840 EP 3843 DI 10.1103/PhysRevLett.83.3840 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200024 ER PT J AU Kress, JD Bickham, SR Collins, LA Holian, BL Goedecker, S AF Kress, JD Bickham, SR Collins, LA Holian, BL Goedecker, S TI Tight-binding molecular dynamics of shock waves in methane SO PHYSICAL REVIEW LETTERS LA English DT Article ID TEMPERATURE; HYDROCARBONS; URANUS; CARBON AB The behavior of shock-compressed methane at high temperatures and pressures is studied using nonequilibrium molecular dynamics and linear-scaling tight-binding electronic structure theory in simulations containing as many as 1728 molecules. For certain piston velocities, a chemical dissociation wave evolves that lags behind the compressive shock front. At about 1 ps, the dissociation region consists mainly of molecular hydrogen and hydrocarbon polymers. Shock wave experiments, which access much longer time scales, suggest that the hydrocarbons ultimately decompose into elemental carbon. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Max Planck Inst Solid State Res, Stuttgart, Germany. RP Kress, JD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 17 TC 43 Z9 44 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 8 PY 1999 VL 83 IS 19 BP 3896 EP 3899 DI 10.1103/PhysRevLett.83.3896 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200038 ER PT J AU Temmerman, WM Szotek, Z Svane, A Strange, P Winter, H Delin, A Johansson, B Eriksson, O Fast, L Wills, JM AF Temmerman, WM Szotek, Z Svane, A Strange, P Winter, H Delin, A Johansson, B Eriksson, O Fast, L Wills, JM TI Electronic configuration of Yb compounds SO PHYSICAL REVIEW LETTERS LA English DT Article ID PR METAL; PRESSURE; CERIUM AB The total energy differences between divalent and trivalent configurations of Yb ions in a number of Yb compounds are studied. Two different band theoretical methods, which differ in the treatment of the localized f electrons, are used. The results show that in all Yb compounds the valence energy differences are equal to the energy needed to localize an f electron. These valence energy differences correlate with the number of f electrons hybridizing with the conduction bands in the trivalent configuration. For divalent YbS, the pressure induced f-electron delocalization implies an intermediate valency, as also indicated by experiment. C1 SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. Univ Keele, Dept Phys, Keele ST5 5BG, Staffs, England. Forschungszentrum Karlsruhe, INFP, D-76021 Karlsruhe, Germany. Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. 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 Temmerman, WM (reprint author), SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RI Strange, Paul/C-9022-2012; Eriksson, Olle/E-3265-2014; Delin, Anna/P-2100-2014; OI Eriksson, Olle/0000-0001-5111-1374; Delin, Anna/0000-0001-7788-6127; Strange, Paul/0000-0001-5818-8032 NR 20 TC 44 Z9 44 U1 2 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 8 PY 1999 VL 83 IS 19 BP 3900 EP 3903 DI 10.1103/PhysRevLett.83.3900 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200039 ER PT J AU Civale, L Silhanek, AV Thompson, JR Song, KJ Tomy, CV Paul, DM AF Civale, L Silhanek, AV Thompson, JR Song, KJ Tomy, CV Paul, DM TI Fourfold basal plane anisotropy of the nonlocal magnetization of YNi2B2C SO PHYSICAL REVIEW LETTERS LA English DT Article ID VORTEX LATTICE TRANSITIONS; NEUTRON-SCATTERING; LUNI2B2C AB Studies of single crystal YNi2B2C have revealed a fourfold anisotropy of the equilibrium maenetization in the square crystallographic basal plane. This pi/2 periodicity occurs deep in the superconductive mixed state. In this crystal symmetry, an ordinary superconductive mass anisotropy (as in usual London theory) allows only a constant, isotropic response. In contrast, the experimental results are well described by generalized London theory incorporating nonlocal electrodynamics, as needed for this clean, intermediate-kappa superconductor. C1 Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RP Civale, L (reprint author), Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. NR 14 TC 21 Z9 21 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 NOV 8 PY 1999 VL 83 IS 19 BP 3920 EP 3923 DI 10.1103/PhysRevLett.83.3920 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200044 ER PT J AU Yu, S Gorny, KR Pennington, CH Hults, WL Smith, JL AF Yu, S Gorny, KR Pennington, CH Hults, WL Smith, JL TI Electron-mediated O-17-Cu-63 spin-spin coupling and electron spin correlations in YBa2Cu3O7 SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; NUCLEAR MAGNETIC-RELAXATION; CUPRATE SUPERCONDUCTORS; TRANSVERSE RELAXATION; LATTICE RELAXATION; NMR EXPERIMENTS; NORMAL-STATE; ECHO DECAY; RESONANCE; CU AB We report spin-echo double resonance NMR measurements of O-17-Cu-63 indirect (electron-mediated) nuclear spin-spin coupling between Cu and O atoms in the CuO2 planes of YBa2CuO7 The magnitude of the measured coupling is anomalously large, to the extent that it is inconsistent with the antiferromagnetic correlations that are invoked to explain the contrasting T-1 behaviors of Cu-63 and O-17. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Yu, S (reprint author), Ohio State Univ, Dept Phys, 174 W 18th Ave, Columbus, OH 43210 USA. NR 39 TC 3 Z9 3 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 8 PY 1999 VL 83 IS 19 BP 3924 EP 3927 DI 10.1103/PhysRevLett.83.3924 PG 4 WC Physics, Multidisciplinary SC Physics GA 253FQ UT WOS:000083546200045 ER PT J AU Liu, HC Mao, XL Yoo, JH Russo, RE AF Liu, HC Mao, XL Yoo, JH Russo, RE TI Early phase laser induced plasma diagnostics and mass removal during single-pulse laser ablation of silicon SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article DE laser ablation; laser induced plasma spectroscopy; plasma temperature; electron number density; crater ID ELECTRON-DENSITY; SPECTROSCOPY; TEMPERATURE; DEPOSITION AB The electron number density and temperature during the early phase (< 300 ns) of laser-induced plasmas from silicon using a 266-nm, 3-ns Nd:YAG laser were deduced via spectroscopic methods. These parameters were measured as a function of delay time vs. irradiance in the range of 2-80 GW/cm(2), and compared with crater volume measurements. A dramatic change in plasma characteristics (electron number density, temperature, and degree of ionization) as well as a sharp increase of mass removal was observed when the irradiance was increased beyond a threshold of 20 GW/cm(2). Possible mechanisms such as inverse bremsstrahlung and self-regulation were used to describe these data in the low irradiance region. Laser self-focusing and critical temperature are discussed to explain the dramatic changes after the irradiance reaches the threshold. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Chinese Acad Sci, Guangzhou Inst Geochem, Canton 510640, Peoples R China. RP Russo, RE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 43 TC 127 Z9 131 U1 2 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD NOV 8 PY 1999 VL 54 IS 11 BP 1607 EP 1624 DI 10.1016/S0584-8547(99)00092-0 PG 18 WC Spectroscopy SC Spectroscopy GA 252MM UT WOS:000083505300005 ER PT J AU Schmidt, JAR Arnold, J AF Schmidt, JAR Arnold, J TI Mono-amidinate complexes stabilized by a new sterically-hindered amidine SO CHEMICAL COMMUNICATIONS LA English DT Article ID ORGANOMETALLIC COMPOUNDS; ORGANOYTTRIUM CHEMISTRY; COORDINATION CHEMISTRY; CRYSTAL-STRUCTURES; = H; DERIVATIVES; LIGANDS; LANTHANIDES; TERPHENYLS; ALUMINUM AB A novel amidinate ligand incorporating a bulky terphenyl group is used to prepare unusual, low-coordinate lithium and yttrium mono-amidinate complexes. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Arnold, J (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Arnold, John/F-3963-2012 OI Arnold, John/0000-0001-9671-227X NR 29 TC 70 Z9 70 U1 1 U2 8 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD NOV 7 PY 1999 IS 21 BP 2149 EP 2150 DI 10.1039/a905620c PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 247UM UT WOS:000083238700003 ER PT J AU Cedeno, W Vemuri, VR AF Cedeno, W Vemuri, VR TI Analysis of speciation and niching in the multi-niche crowding GA SO THEORETICAL COMPUTER SCIENCE LA English DT Article DE genetic algorithms; multimodal functions; niching; speciation AB The multi-niche crowding genetic algorithm (MNC GA) has demonstrated its ability to maintain population diversity and stable subpopulations while allowing different species to evolve naturally in different niches of the fitness landscape. These properties are a consequence, in part, to the effect of crowding selection and worst among most similar replacement genetic operators. In this paper we take a closer look at these genetic operators and present mathematical results that show their effect on the population when used in the MNC GA. We also present some guidelines about the parameter values to use in these genetic operators to achieve the desired niching pressure during a run. We conclude with a list of unexplored avenues that might be helpful in a future analysis of the behaviour of the MNC GA. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Hewlett Packard Corp, Res & Dev, Wilmington, DE 19808 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Hewlett Packard Corp, Res & Dev, 1850 Ctr Ville Rd,MS-2C10, Wilmington, DE 19808 USA. EM wcedeno@lf.hp.com; vemuri1@llnl.gov NR 24 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3975 EI 1879-2294 J9 THEOR COMPUT SCI JI Theor. Comput. Sci. PD NOV 6 PY 1999 VL 229 IS 1-2 BP 177 EP 197 DI 10.1016/S0304-3975(99)00093-6 PG 21 WC Computer Science, Theory & Methods SC Computer Science GA 257WV UT WOS:000083806200008 ER PT J AU Tholudur, A Ramirez, WF McMillan, JD AF Tholudur, A Ramirez, WF McMillan, JD TI Mathematical modeling and optimization of cellulase protein production using Trichoderma reesei RL-P37 SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE kinetic modeling; neural networks; parameter function modeling; cellulase production; Trichoderma reesei ID XYLOSE-BASED MEDIA; FED-BATCH CULTURE; ENHANCED PRODUCTION; ENZYME-PRODUCTION; RUT C30; GROWTH; NETWORKS AB The enzyme cellulase, a multienzyme complex made up of several proteins, catalyzes the conversion of cellulose to glucose in an enzymatic hydrolysis-based biomass-to-ethanol process. Production of cellulase enzyme proteins in large quantities using the fungus Trichoderma reesei requires understanding the dynamics of growth anti enzyme production. The method of neural network parameter function modeling, which combines the approximation capabilities of neural networks with fundamental process knowledge, is utilized to develop a mathematical model of this dynamic system. in addition, kinetic models are also developed. Laboratory data from bench-scale fermentations involving growth and protein production by T. reesei on lactose and xylose are used to estimate the parameters in these models. The relative performances of the various models and the results of optimizing these models on two different performance measures are presented. An;approximately 33% lower root-mean-squared error (RMSE) in protein predictions and about 40% lower total RMSE is obtained with the neural network-based model as opposed to kinetic models. Using the neural network-based model, the RMSE in predicting optimal conditions for two performance indices, is about 67% and 40% lower, respectively, when compared with the kinetic models. Thus, both model predictions and optimization results from the neural network-based model are found to be closer to the experimental data than the kinetic models developed in this work. It is shown that the neural network parameter function modeling method can be useful as a "macromodeling" technique to rapidly develop dynamic models of a process. (C) 1999 John Wiley & Sons, Inc. C1 Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Biotechnol Ctr Fuels & Chem, Golden, CO USA. RP Ramirez, WF (reprint author), Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. NR 32 TC 27 Z9 28 U1 1 U2 5 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD NOV 5 PY 1999 VL 66 IS 1 BP 1 EP 16 DI 10.1002/(SICI)1097-0290(1999)66:1<1::AID-BIT1>3.0.CO;2-K PG 16 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 260GJ UT WOS:000083940900001 PM 10556790 ER PT J AU Wang, XB Wang, LS AF Wang, XB Wang, LS TI Vibrationally resolved photoelectron spectroscopy of PO3- and the electronic structure of PO3 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID META-PHOSPHATE ANION; GAS-PHASE; SOLID ARGON; PHOSPHORUS; ABINITIO; METAPHOSPHATE; HYDRATION; STATES; RACEMIZATION; MECHANISMS AB A vibrationally resolved photoelectron spectrum has been obtained for PO3- at 193 nm in the gas phase. Transitions to the ground (X(2)A'(2)) and first excited state (A(2)E ") of PO3 were observed. The current spectrum represents the first observation of the E-2 " state, which splits into two states, B-2(1) and (2)A(2), due to the Jahn-Teller effect. The (2)A'(2) ground state shows a vibrational progression in the nu(1) symmetric stretching mode with a frequency of 1000 (100) cm(-1). The adiabatic electron affinity of PO3 was measured to be very high, 4.95 (0.06) eV. The B-2(1) and (2)A(2) states of PO3 show very broad features due to the large geometry changes between these states and the anion ground state. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. EM ls.wang@pnl.gov NR 32 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD NOV 5 PY 1999 VL 313 IS 1-2 BP 179 EP 183 DI 10.1016/S0009-2614(99)00993-8 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 256KE UT WOS:000083723800028 ER PT J AU Langan, P Schoenborn, BP AF Langan, P Schoenborn, BP TI Need for neutron diffraction instruments SO SCIENCE LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Langan, P (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Langan, Paul/N-5237-2015 OI Langan, Paul/0000-0002-0247-3122 NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD NOV 5 PY 1999 VL 286 IS 5442 BP 1089 EP 1089 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 253AJ UT WOS:000083534200018 PM 10610521 ER PT J AU Richter, B AF Richter, B TI Megascience Forum: Valuable from IUPAP's perspective SO SCIENCE LA English DT Letter C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Richter, B (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD NOV 5 PY 1999 VL 286 IS 5442 BP 1089 EP 1089 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 253AJ UT WOS:000083534200017 ER PT J AU Chen, CY Li, YM Bailey, K O'Connor, TP Young, L Lu, ZT AF Chen, CY Li, YM Bailey, K O'Connor, TP Young, L Lu, ZT TI Ultrasensitive isotope trace analyses with a magneto-optical trap SO SCIENCE LA English DT Article ID ICE CORE; SAMPLES; ATOMS; KR-81 AB Laser manipulation of neutral atoms has been used to count individual krypton-85 and krypton-81 atoms present in a natural krypton gas sample with isotopic abundances in the range of 10(-11) and 10(-13), respectively. This method of isotope trace analysis is free of contamination from other isotopes and elements and can be applied to several different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10(-7). System improvements could increase the efficiency by many orders of magnitude. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Lu, ZT (reprint author), Argonne Natl Lab, Div Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 32 TC 117 Z9 121 U1 1 U2 16 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 NOV 5 PY 1999 VL 286 IS 5442 BP 1139 EP 1141 DI 10.1126/science.286.5442.1139 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 253AJ UT WOS:000083534200038 ER PT J AU Schaaff, TG Whetten, RL AF Schaaff, TG Whetten, RL TI Controlled etching of Au : SR cluster compounds SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID NANOCRYSTAL GOLD MOLECULES; SELF-ASSEMBLED MONOLAYERS; 3-DIMENSIONAL MONOLAYERS; NANOPARTICLES; DYNAMICS; SPECTRA; NMR; SIZE AB When Au:SR cluster compounds (R = (CH2)(5)CH3) with an Au metallic cluster core mass of similar to 14 kDa (similar to 75 atoms, 1.1 nm equivalent diameter), are heated in neat dodecane-thiol solution under inert atmosphere, species with smaller Au core masses are formed, presumably by the removal of Au atoms from the outermost surface layer of the cluster's Au core. This process was monitored through laser desorption mass spectrometry, optical absorption spectroscopy, and X-ray diffraction, where all three methods indicate a substantial decrease (>50%, by mass or number of Au atoms) in the size of the cluster compound's inorganic core. The optical absorption spectra and laser desorption mass spectra of the compounds generated by etching are strikingly similar to compounds previously separated without an etching step. The dual function of the thiol as both stabilizing adsorbate and efficient etchant sets this cluster (or nanocrystal) system apart from other metallic and semiconductor systems. C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. RP Schaaff, TG (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 36 TC 179 Z9 179 U1 3 U2 32 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 NOV 4 PY 1999 VL 103 IS 44 BP 9394 EP 9396 DI 10.1021/jp993229d PG 3 WC Chemistry, Physical SC Chemistry GA 257CC UT WOS:000083763700004 ER PT J AU Xue, ZY Schrader, GL AF Xue, ZY Schrader, GL TI In situ laser Raman spectroscopy studies of VPO catalyst transformations SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID VANADYL PYROPHOSPHATE CATALYSTS; MALEIC-ANHYDRIDE SYNTHESIS; N-BUTANE OXIDATION; P-O CATALYSTS; SELECTIVE OXIDATION; HYDROGEN PHOSPHATE; OXIDE CATALYSTS; VO(HPO4).0.5H2O; (VO)2H4P2O9; CHEMISTRY AB VPO catalyst transformations were investigated using in situ laser Raman spectroscopy. During reduction-oxidation step changes, (VO)(2)P2O7 was readily converted to alpha(II)-, delta-VOPO4, and ultimately to beta-VOPO4 in O-2/N-2; these V5+ phases were eliminated in n-butane/N-2. A wet N-2 feed (5-10% H2O in N-2) transformed (VO)(2)P2O7 and alpha(I)-, alpha(II)-, beta-, delta-, gamma-VOPO4 to V2O5 at temperatures above 400 degrees C. The presence of water vapor facilitated the loss of oxygen atoms involved in V-O-P bonding, and separated vanadium oxide and phosphorus oxide species were formed. The isolated vanadium oxide species could be transformed to V2O5; phosphorus species likely diffused from the catalyst lattice in the form of acid phosphates. C1 Iowa State Univ, Dept Chem Engn, Ames, IA 50011 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP Schrader, GL (reprint author), Iowa State Univ, Dept Chem Engn, Ames, IA 50011 USA. NR 35 TC 49 Z9 50 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 4 PY 1999 VL 103 IS 44 BP 9459 EP 9467 DI 10.1021/jp9912713 PG 9 WC Chemistry, Physical SC Chemistry GA 257CC UT WOS:000083763700011 ER PT J AU Markovic, NM Lucas, CA Grgur, BN Ross, PN AF Markovic, NM Lucas, CA Grgur, BN Ross, PN TI Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article AB The Pt(100)-CO interaction in aqueous electrolytes was examined by using rotating disk methods in combination with in-situ surface X-ray scattering (SXS) measurements. The analysis of the SXS results indicates that the topmost platinum atoms expand away from the second layer by ca. 4% when H-upd was completely displaced from Pt(100) by CO to form a saturated layer of CO. Assuming that gas-phase heats of adsorption for CO apply as well to the liquid-solid interface, we estimate that the Gibbs energy change for the displacement of Hupd by CO On Pt(100) is close to -90 kJ/mol. A Pt(100)-CO surface normal interlayer spacing of 1.4 +/- 0.4 Angstrom was extracted from SXS measurements, suggesting that CO is adsorbed primarily at the 2-fold bridge-bonded sites, or possibly a mixture of bridge and atop sites. In contrast to the Pt(111)-CO system, no structures of COad with long-range order were formed on Pt(100). Two different forms of COad are formed at the Pt(100)-electrolyte interface: the weakly adsorbed state which is oxidized in the pre-ignition potential region, and the strongly adsorbed state which is oxidized in the ignition potential region. Although the nature of COad is different before and after the ignition potential, we proposed that the mechanism for CO oxidation on Pt(100) is the same in both the pre-ignition and ignition potential regions, e.g., adsorbed CO reacts with hydroxyl species (OHad) through a Langmuir-Hinshelwood type reaction. The kinetics of CO oxidation on Pt(hkl) surfaces is found to vary with crystal face. The difference in activity is attributed to the structure-sensitive adsorption of CO, OHad, and anions from the supporting electrolytes. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. RP Markovic, NM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Mail Stop 2-100, Berkeley, CA 94720 USA. OI Grgur, Branimir/0000-0003-4684-9053 NR 36 TC 79 Z9 81 U1 3 U2 20 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 NOV 4 PY 1999 VL 103 IS 44 BP 9616 EP 9623 DI 10.1021/jp991566g PG 8 WC Chemistry, Physical SC Chemistry GA 257CC UT WOS:000083763700033 ER PT J AU Jankowiak, R Ratsep, M Picorel, R Seibert, M Small, GJ AF Jankowiak, R Ratsep, M Picorel, R Seibert, M Small, GJ TI Excited states of the 5-chlorophyll photosystem II reaction center SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PRIMARY CHARGE SEPARATION; REACTION-CENTER COMPLEX; PHOTOSYNTHETIC REACTION CENTERS; D1-D2-CYT B-559 COMPLEX; PRIMARY ELECTRON-DONOR; RHODOPSEUDOMONAS-VIRIDIS; EXCITATION-ENERGY; CHLOROPHYLL-A; SPECTROSCOPIC CHARACTERIZATION; SUBPICOSECOND EQUILIBRATION AB Results of 4.2 K hole burning, chemical reduction (sodium dithionite, in dark and with illumination), and oxidation (ferricyanide) experiments are reported for the isolated PS II reaction center containing five chlorophyll (Chl) molecules (RC-5). Q(y) states at 679.6 and 668.3 nm are identified as being highly localized on pheophytin a of the D-1 branch (Pheo(1)) and pheophytin a of the D-2 branch (Pheo(2)), respectively. The Pheo(1)-Q(x) and Pheo(2)-Q(x) transitions were found to lie on the low and high energy sides of the single Pheo-Q(x) absorption band, at 544.4 and 541.2 nm, respectively. The Q(y) band of the 684 nm absorbing Chl, which is more apparent in absorption in RC-5 than in RC-6 samples, is assigned to the peripheral Chl on the D1 side. The results are consistent with that peripheral Chl being Chl, (Stewart, D. H.; Cua, A.; Chisholm, D. A.; Diner, B. A.; Bocian, D. F.; Brudvig, G. W. Biochemistry 1998, 37, 10040). The results indicate that P680, the primary electron donor, is the main acceptor for energy transfer from the Pheo(1)-Q(y) state and that excitation energy transfer from the Pheo(1)-Q(y) state and P680* to the 684 nm Chl is inefficient. It is concluded that the procedure used to prepare RC-5 has only a small effect on the energies of the Q(y) states associated with the core cofactors of the 6-Chl RC as well as the 684 nm Chl. Implications of the results for the multimer model (Durrant, J. R.; Klug, D. R; Kwa, S. L. S.; van Grondelle, R.; Porter, G.; Dekker, J. P. Proc. Natl. Acad. Sci. U.S.A. 1995, 92, 4798) are considered. In that model the Q(y)-states of the core are significantly delocalized over several cofactors. The results presented provide no support for this model. C1 Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. CSIC, E-50080 Zaragoza, Spain. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Small, GJ (reprint author), Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. RI PICOREL, RAFAEL/K-7930-2014 OI PICOREL, RAFAEL/0000-0003-3791-129X NR 61 TC 47 Z9 49 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 4 PY 1999 VL 103 IS 44 BP 9759 EP 9769 DI 10.1021/jp9906738 PG 11 WC Chemistry, Physical SC Chemistry GA 257CC UT WOS:000083763700052 ER PT J AU Franceschetti, A Zunger, A AF Franceschetti, A Zunger, A TI The inverse hand-structure problem of finding an atomic configuration with given electronic properties SO NATURE LA English DT Article ID ALLOYS AB Modern crystal-growth techniques, such as molecular beam epitaxy or metal-organic chemical-vapour deposition, are capable of producing prescribed crystal structures, sometimes even in defiance of equilibrium, bulk thermodynamics. These techniques open up the possibility of exploring different atomic arrangements in search of a configuration that possesses given electronic and optical properties'. Unfortunately, the number of possible combinations is so vast, and the electronic properties are so sensitive to the details of the crystal structure, that simple trial-and-error methods (such as those used in combinatorial synthesis(2)) are unlikely to be successful. Here we describe a theoretical method that addresses the problem of finding the atomic configuration of a complex, multi-component system having a target electronic-structure property. As an example, we predict that the configuration of an Al0.25Ga0.75As alloy having the largest Optical bandgap is a (GaAs)(2)(AlAs)(1)(GaAs)(4)(AlAs)(1) superlattice oriented in the [201] direction. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Franceschetti, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 12 TC 140 Z9 140 U1 1 U2 23 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 4 PY 1999 VL 402 IS 6757 BP 60 EP 63 DI 10.1038/46995 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 254XC UT WOS:000083638600040 ER PT J AU Marcotte, EM Pellegrini, M Thompson, MJ Yeates, TO Eisenberg, D AF Marcotte, EM Pellegrini, M Thompson, MJ Yeates, TO Eisenberg, D TI A combined algorithm for genome-wide prediction of protein function SO NATURE LA English DT Article ID SACCHAROMYCES-CEREVISIAE; COLON-CANCER; GENES; YEAST; DATABASE; INTERACT; MUTATION; HOMOLOG; MSH6 AB The availability of over 20 fully sequenced genomes has driven the development of new methods to find protein function and interactions. Here we group proteins by correlated evolution(1), correlated messenger RNA expression patterns(2) and patterns of domain fusion(3) to determine functional relationships among the 6,217 proteins of the yeast Saccharomyces cervisiae. Using these methods, we discover over 93,000 pairwise links between functionally related yeast proteins. Links between characterized and uncharacterized proteins allow a general function to be assigned to more than half of the 2,557 previously uncharacterized yeast proteins. Examples of functional links are given for a protein family of previously unknown function, a protein whose human homologues are implicated in colon cancer and the yeast prion Sup35. C1 Univ Calif Los Angeles, Inst Mol Biol, US DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, Inst Mol Biol, US DOE, Lab Struct Biol & Mol Med, POB 951570, Los Angeles, CA 90095 USA. OI Yeates, Todd/0000-0001-5709-9839 NR 26 TC 621 Z9 652 U1 2 U2 15 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 4 PY 1999 VL 402 IS 6757 BP 83 EP 86 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 254XC UT WOS:000083638600047 PM 10573421 ER PT J AU Balana, ME Lupu, R Labriola, L Charreau, EH Elizalde, PV AF Balana, ME Lupu, R Labriola, L Charreau, EH Elizalde, PV TI Interactions between progestins and heregulin (HRG) signaling pathways: HRG acts as mediator of progestins proliferative effects in mouse mammary adenocarcinomas SO ONCOGENE LA English DT Article DE progestin; heregulin; mouse mammary tumors; type I insulin-like growth factor receptor ID BREAST-CANCER CELLS; NEU DIFFERENTIATION FACTOR; EPIDERMAL GROWTH-FACTOR; FACTOR-I RECEPTOR; MEDROXYPROGESTERONE ACETATE; TRANSDUCTION PATHWAYS; ESTROGEN-RECEPTOR; EPITHELIAL-CELLS; TUMOR-CELLS; EXPRESSION AB The present study addressed links between progestin and heregulin (HRG) signaling pathways in mammary tumors. An experimental model of hormonal carcinogenesis, in which the synthetic progestin medroxyprogesterone acetate (MPA) induced mammary adenocarcinomas in female Balb/c mice, was used. MPA induced an in vivo up-regulation of HRG mRNA expression in progestin-dependent (HD) tumor lines. Mammary tumor progression to a progestin-independent (HI) phenotype was accompanied by a high constitutive expression of HRG. The HRG message arose from the tumor epithelial cells. Primary cultures of malignant epithelial cells from a HD tumor line were used to investigate HRG involvement on cell proliferation. HRG induced a potent proliferative effect on these cells and potentiated MPA mitogenic effects. Blocking endogenous HRG synthesis by antisense oligodeoxynucleotides (ASODNs) to HRG mRNA inhibited MPA-induced cell growth, indicating that HRG acts as a mediator of MPA-induced growth. High levels of ErbB-2 and ErbB-3 expression and low ErbB-4 levels mere found in HD cells. Treatment of these cells with either MPA or HRG resulted in tyrosine phosphorylation of both ErbB-2 and ErbB-3. Furthermore, both HRG and MPA proliferative effects mere abolished when cells were treated with ASODNs to ErbB-2 mRNA, providing evidence for a critical role of ErbB-2 in HRG-induced growth. Finally, blocking type I insulin-like growth factor receptor (IGF-IR) expression with ASODN resulted in the complete inhibition of HRG proliferative effect, demonstrating that a functional IGF-IR is required for HRG mitogenic activity. These results provide the first evidence of interactions between progestins and HRB/ErbB signal transduction pathways in mammary cancer and the first demonstration that IGF-IR is required for HRG proliferative effects. C1 Inst Biol & Med Expt, RA-1428 Buenos Aires, DF, Argentina. Univ Calif Berkeley, Lawrence Berkeley Natl Labs, Berkeley, CA 94710 USA. RP Elizalde, PV (reprint author), Inst Biol & Med Expt, Obligado 2490, RA-1428 Buenos Aires, DF, Argentina. RI Labriola, Leticia/E-9059-2012 OI Labriola, Leticia/0000-0003-3899-6088 NR 43 TC 43 Z9 43 U1 0 U2 1 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD NOV 4 PY 1999 VL 18 IS 46 BP 6370 EP 6379 DI 10.1038/sj.onc.1203028 PG 10 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 260DK UT WOS:000083934100022 PM 10597237 ER PT J AU Mohapatra, RN Nandi, S Perez-Lorenzana, A AF Mohapatra, RN Nandi, S Perez-Lorenzana, A TI Neutrino masses and oscillations in models with large extra dimensions SO PHYSICS LETTERS B LA English DT Article ID COMPACTIFICATION; MILLIMETER AB We discuss the profile of neutrino masses and mixings in models with large extra dimensions when right handed neutrinos are present in the branes along with the usual standard model particles. In these models, string scale must be bigger than 10(8) GeV to have desired properties for the neutrinos at low energies. The lightest neutrino mass is zero and there is oscillations to sterile neutrinos that are different from other models with the bulk neutrino. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Inst Politecn Nacl, Ctr Invest & Estudios Avanzados, Dept Fis, Mexico City 07000, DF, Mexico. RP Mohapatra, RN (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NR 54 TC 108 Z9 108 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 NOV 4 PY 1999 VL 466 IS 2-4 BP 115 EP 121 DI 10.1016/S0370-2693(99)01119-3 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 257YT UT WOS:000083810900006 ER PT J AU Atwood, D Soni, A AF Atwood, D Soni, A TI General analysis of B decays to two pseudoscalars for EWP, rescattering and color suppression effects SO PHYSICS LETTERS B LA English DT Article ID PENGUIN DIAGRAMS; ANGLE-GAMMA; CP AB A general analysis for B decays to two pseudoscalars, involving ten modes, is presented. a Pimple model for final state interactions and rescattering effects is proposed. We show how the data can be used to deduce important information on electroweak penguins (EWP), rescattering and color suppression effects and on the CKM parameters in a largely model independent way by using chi(2)-minimization. We fmd that the current data suggests the presence of color-suppressed tree at levels somewhat larger than simple theoretical estimates. Once the data improves the extraction of alpha and/or gamma may become feasible with this method as we illustrate with the existing data. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Brookhaven Natl Lab, Theory Grp, Upton, NY 11973 USA. RP Atwood, D (reprint author), Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. NR 29 TC 8 Z9 8 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 NOV 4 PY 1999 VL 466 IS 2-4 BP 326 EP 332 DI 10.1016/S0370-2693(99)01086-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 257YT UT WOS:000083810900036 ER PT J AU Langan, P Nishiyama, Y Chanzy, H AF Langan, P Nishiyama, Y Chanzy, H TI A revised structure and hydrogen-bonding system in cellulose II from a neutron fiber diffraction analysis SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID D-CELLOTETRAOSE HEMIHYDRATE; STATE C-13 NMR; CRYSTAL-STRUCTURE; PACKING ANALYSIS; NATIVE CELLULOSE; POLYSACCHARIDES; HYDRATION; MODEL; DNA AB The crystal and molecular structure and hydrogen bonding system in cellulose II have been revised using new neutron diffraction data extending to 1.2 Angstrom resolution collected from two highly crystalline fiber samples of mercerized flax, Mercerization was achieved in NaOH/H2O for one sample and in NaOD/D2O for the other, corresponding to the labile hydroxymethyl moieties being hydrogenated and deuterated, respectively. Fourier difference maps were calculated in which neutron difference amplitudes were combined with phases calculated from two revised X-ray models of cellulose II, A and B'. The revised phasing models were determined by refinement against the X-ray data set of Kolpak and Blackwell,(8) using the LALS methadology.(37) Both models A and B' have two antiparallel chains organized in a P2(1) space group and unit cell parameters: a = 8.01 Angstrom; b = 9.04 Angstrom, c = 10.36 Angstrom, and gamma = 117.1 degrees.(15) Model A has equivalent backbone conformations for both chains but different conformations for the hydroxymethyl moieties: gt for the origin chain and fg for the center chain. Model B', based on the recent crystal structures of cellotetraose,(21-23) has different conformations for the two chains but nearly equivalent conformations for the hydroxymethyl moieties. On the basis of the X-ray data alone, model A and model B' could not be differentiated. From the neutron Fourier difference maps, possible labile hydrogen atom positions were identified for each model and refined using LALS. We were able to eliminate model A in favor of model B'. The hydrogen-bonding scheme identified for model B' is significantly different from previous proposals based on the crystal structures of cellotetraose,(21-23) MD simulations of cellulose II,(25),and any potential hydrogen-bonding network in the structure of cellulose II determined in earlier X-ray fiber diffraction studies.(7,8) The exact localization of the labile hydrogen atoms involved in this bonding, together with their donor and acceptor characteristics, is presented and discussed. This study provides, for the first time, the coordinates of all of the atoms in cellulose II. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Tokyo, Grad Sch Agr & Life Sci, Tokyo 113, Japan. Univ Grenoble 1, CNRS, Ctr Rech Macromol Vegetales, F-38041 Grenoble, France. RP Langan, P (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, MS-M888, Los Alamos, NM 87545 USA. RI Nishiyama, Yoshiharu/A-3492-2012; Chanzy, Henri/A-3526-2012; Langan, Paul/N-5237-2015 OI Nishiyama, Yoshiharu/0000-0003-4069-2307; Langan, Paul/0000-0002-0247-3122 NR 44 TC 200 Z9 202 U1 9 U2 91 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 NOV 3 PY 1999 VL 121 IS 43 BP 9940 EP 9946 DI 10.1021/ja9916254 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 254YH UT WOS:000083641500006 ER PT J AU Izumi, Y Glaser, T Rose, K McMaster, J Basu, P Enemark, JH Hedman, B Hodgson, KO Solomon, EI AF Izumi, Y Glaser, T Rose, K McMaster, J Basu, P Enemark, JH Hedman, B Hodgson, KO Solomon, EI TI Ligand K-edge and metal L-edge X-ray absorption spectroscopy and density functional calculations of oxomolybdenum complexes with thiolate and related ligands: Implications for sulfite oxidase SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID OXYGEN-ATOM TRANSFER; BLUE COPPER SITE; ELECTRON-PARAMAGNETIC-RESONANCE; IRON MOLYBDENUM COFACTOR; OXO-TRANSFER; DIOXOMOLYBDENUM(VI) COMPLEXES; PHOTOELECTRON-SPECTROSCOPY; STRUCTURAL INSIGHTS; SULFUR COVALENCY; DONOR LIGANDS AB X-ray absorption spectra have been measured at the S K-, Cl K-, and Mo L-3- and L-2-edges for the d(0) dioxomolybdenum(VI) complexes LMoO2(SCH2Ph), LMoO2Cl, and LMoO2(OPh) (L = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) to investigate ligand-metal covalency and its effects on oxo transfer reactivity. Two dominant peaks are observed at the S K-edge (2470.5 and 2472.5 eV) for LMoO2(SCH2Ph) and at the Cl K-edge (2821.9 and 2824.2 eV) for LMoO2Cl, demonstrating two major covalent contributions from S and Cl to the Mo d orbitals. Density functional calculations were performed on models of the three Mo complexes, and the energies and characters of the Mo 4d orbitals were interpreted in terms of the effects of two strong cis-oxo bonds and additional perturbations due to the thiolate, chloride, or alkoxide ligand. The major perturbation effects are for thiolate and Cl- pi mixed with the d(xz) orbital and sigma mixed with the d(z)(2) orbital. The calculated 4d orbital energy splittings for models of these two major contributions to the bonding of thiolate and Cl ligands (2.47 and 2.71 eV, respectively) correspond to the splittings observed experimentally for the two dominant ligand K-edge peaks for LMoO2(SCH2Ph) and LMoO2Cl (2.0 and 2.3 eV, respectively) after consideration of final state electronic relaxation. Quantification of the S and Cl covalencies in the d orbital manifold from the pre-edge intensity yields, similar to 42% and similar to 17% for LMoO2(SCH2Ph) and LMoO2Cl respectively. The Mo L-2-edge spectra provide a direct probe of metal 4d character for the three Mo complexes. The spectra contain a strong, broad peak and two additional sharp peaks at higher energy, which are assigned to 2p transitions to the overlapping t(2g) set and to the d(z)(2) and d(xy) levels, respectively. The total peak intensities of the Mo L-2-edges for LMoO2(OPh) and LMoO2Cl are similar to and larger than those for LMoO2(SCH2Ph), which agrees with the calculated trend in ligand-metal covalency. The theoretical and experimental description of bonding developed from these studies provides insight into the relationship of electronic structure to the oxo transfer chemistry observed for the LMoO2X complexes. These results imply that anisotropic covalency of the Mo-S-cys bond in sulfite oxidase may promote preferential transfer of one of the oxo groups during catalysis. C1 Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. RP Enemark, JH (reprint author), Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. RI Basu, Partha/G-2424-2011; McMaster, Jonathan/P-2978-2015; Glaser, Thorsten/H-5187-2013; OI McMaster, Jonathan/0000-0003-0917-7454; Glaser, Thorsten/0000-0003-2056-7701; Izumi, Yasuo/0000-0001-8366-1864 NR 74 TC 57 Z9 57 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD NOV 3 PY 1999 VL 121 IS 43 BP 10035 EP 10046 DI 10.1021/ja9903678 PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA 254YH UT WOS:000083641500019 ER PT J AU Boldyrev, AI Simons, J Li, X Wang, LS AF Boldyrev, AI Simons, J Li, X Wang, LS TI pi- and sigma-coordinated Al in AlC2- and AlCSi-. A combined photoelectron spectroscopy and ab initio study SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAUSSIAN-BASIS SETS; SI2C; ATOMS; MOLECULES; EXCHANGE; CLUSTERS; SPECTRUM; STATES; C4LI4 AB Vibrationally resolved photoelectron spectroscopy is combined with ab initio calculations to investigate the structure and chemical bonding in AlC2- and AlCSi-. AlC2- was found to have a C-2v structure whereas AlCSi- was found to be almost linear, thus establishing pi-coordination of Al in AlC2- and sigma-coordination in AlCSi-. The adiabatic electron affinities of AlC2- and AlCSi were measured to be 2.65(3) and 2.50(6) eV, respectively. The calculated vertical (2.87 eV) and adiabatic (2.60 eV) electron detachment energies for AlC2- agree well with the 2.73(0.03) and 2.65(0.93) eV experimental values, respectively. The calculated (2.86 eV) and experimental (2.64 +/- 0.04 eV) vertical detachment energies for AlCSi- were also in good agreement. The calculated vibrational frequency for AlC2 and vertical detachment energies for other higher energy features in both AlC2- and AlCSi- were also in good agreement with the experimental measurements. The combined experimental and theoretical effort allows us to elucidate the structures of AlC2- and AlCSi- and the nature of their chemical bonding. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Boldyrev, AI (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RI Boldyrev, Alexander/C-5940-2009 OI Boldyrev, Alexander/0000-0002-8277-3669 NR 35 TC 29 Z9 30 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD NOV 3 PY 1999 VL 121 IS 43 BP 10193 EP 10197 DI 10.1021/ja992102z PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA 254YH UT WOS:000083641500037 ER PT J AU Bielicki, JK Oda, MN Forte, TM AF Bielicki, JK Oda, MN Forte, TM TI Influence of Arg -> Cys substitutions on apolipoprotein A-I (apoA-I) dimerization and cellular cholesterol efflux SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 8 BP 2 EP 2 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100009 ER PT J AU Oda, MN Voss, J Forte, TM AF Oda, MN Voss, J Forte, TM TI Apolipoprotein A-I (apoA-I) lipid-free structure examined by EPR spectroscopy: Insights into C-terminal function SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Lab, Berkeley, CA USA. Univ Calif Davis, Davis, CA 95616 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 7 BP 2 EP 2 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100008 ER PT J AU Blanche, PJ Hoff, LG Shoukry, MI Krauss, RM AF Blanche, PJ Hoff, LG Shoukry, MI Krauss, RM TI Absence of hepatic lipase results in reduction of human-like small dense LDL in fat-fed Human-ApoB transgenic mice SO CIRCULATION LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 64 BP 13 EP 13 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100065 ER PT J AU Spencer, RH Grandas, OH Stevens, SL Goldman, MH Stabin, MG Knapp, FF Costanza, MJ Freeman, MB Scott, JC Bresee, SJ Donnell, RL Wortham, DC AF Spencer, RH Grandas, OH Stevens, SL Goldman, MH Stabin, MG Knapp, FF Costanza, MJ Freeman, MB Scott, JC Bresee, SJ Donnell, RL Wortham, DC TI Dosimetry considerations of (188)rhenium perrhenate liquid-filled balloons in the prevention of restenosis of injured swine iliac arteries SO CIRCULATION LA English DT Meeting Abstract C1 Univ Tennessee, Mem Res Ctr & Hosp, Knoxville, TN USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 156 BP 31 EP 31 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100157 ER PT J AU Weinberger, J Schiff, PB Trichter, F Wuu, CS Knapp, FF Schwartz, A AF Weinberger, J Schiff, PB Trichter, F Wuu, CS Knapp, FF Schwartz, A TI Results of the Columbia safety and feasibility (CURE) trial of liquid radioisotopes for coronary vascular brachytherapy SO CIRCULATION LA English DT Meeting Abstract C1 Columbia Presbyterian Med Ctr, New York, NY 10032 USA. ORNL, Oak Ridge, TN USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 385 BP 75 EP 75 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100386 ER PT J AU Blanche, PJ Holl, LG Rubin, EM Krauss, RM AF Blanche, PJ Holl, LG Rubin, EM Krauss, RM TI Effect of dietary milkfat and added cholesterol on plasma Lp(a), ApoB and lipid levels in human-apoB : apo(a) transgenic mice SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 593 BP 115 EP 115 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100593 ER PT J AU Ueda, Y Gong, EL Royer, L Rubin, EM Francone, OL AF Ueda, Y Gong, EL Royer, L Rubin, EM Francone, OL TI SR-BI transgenics: Insights into atherogenesis and lipoprotein metabolism. SO CIRCULATION LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Pfizer Inc, Groton, CT 06340 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 975 BP 189 EP 189 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417100974 ER PT J AU Rizzo, M Wang, JM Blanche, PJ Barbagallo, CM Taylor, JM Krauss, RM AF Rizzo, M Wang, JM Blanche, PJ Barbagallo, CM Taylor, JM Krauss, RM TI Expression of hepatic lipase in human apoB transgenic rabbits reduces total LDL and increases small, dense LDL SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. Univ Calif San Francisco, Gladstone Inst Cardiovasc Dis, San Francisco, CA 94141 USA. Ist Med Int & Geriatria, Palermo, Italy. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 1324 BP 255 EP 255 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417101323 ER PT J AU McCall, MR Carr, AC Forte, TM Frei, B AF McCall, MR Carr, AC Forte, TM Frei, B TI LDL modified by hypochlorous acid (HOCL) is a potent inhibitor of lecithin: Cholesterol acyltransferase (LCAT) activity in plasma SO CIRCULATION LA English DT Meeting Abstract C1 Oregon State Univ, Corvallis, OR 97331 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 1359 BP 261 EP 261 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417101358 ER PT J AU Bielicki, JK Lee, M Forte, TM AF Bielicki, JK Lee, M Forte, TM TI Phospholipid hydroperoxides (PL-OOH) inhibit plasma lecithin : cholesterol acyltransferase (LCAT) activity: evidence that paraoxonase (PON) may play a role in preserving LCAT activity during early atherogenesis SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 2104 BP 401 EP 401 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417102102 ER PT J AU Jong, MC Zhu, Y Frazer, KA Gong, RL Krauss, RM Zhang, J Cheng, JF Rubin, EM Berkeley, L AF Jong, MC Zhu, Y Frazer, KA Gong, RL Krauss, RM Zhang, J Cheng, JF Rubin, EM Berkeley, L TI Transgene complementation of a 450 kb targeted deletion identifies OCTN2 as a modulator of triglyceride production SO CIRCULATION LA English DT Meeting Abstract C1 Gaubius, Leiden, Netherlands. Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3214 BP 610 EP 610 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103210 ER PT J AU Bristow, J Friddle, CJ Koga, T Rubin, EM AF Bristow, J Friddle, CJ Koga, T Rubin, EM TI Novel cardiac hypertrophy genes identified by cDNA microarray analysis SO CIRCULATION LA English DT Meeting Abstract C1 Univ Calif San Francisco, San Francisco, CA 94143 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3362 BP 638 EP 638 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103358 ER PT J AU Krauss, RM Cantor, RM Holl, LG Bianche, PJ Rithaporn, T Rawlings, RS Fernstrom, HS Orr, JR Dreon, DM Davis, RC Lusis, AJ Rotter, JI AF Krauss, RM Cantor, RM Holl, LG Bianche, PJ Rithaporn, T Rawlings, RS Fernstrom, HS Orr, JR Dreon, DM Davis, RC Lusis, AJ Rotter, JI TI Linkage of LDL subclass phenotypes to the LDL receptor gene locus on high-fat and low-fat diets SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. Univ Calif Los Angeles, Los Angeles, CA USA. Childrens Hosp Oakland, Oakland, CA 94609 USA. Cedars Sinai Med Ctr, Los Angeles, CA 90048 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3471 BP 659 EP 659 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103467 ER PT J AU Erickson, SK Lear, SR Shefer, S Blanche, PJ Berkeley, L Batta, AK Krauss, RM Salen, G AF Erickson, SK Lear, SR Shefer, S Blanche, PJ Berkeley, L Batta, AK Krauss, RM Salen, G TI Effect of cholesterol 7 alpha-hydroxylase (cyp7A) gene knockout on lipid homeostasis SO CIRCULATION LA English DT Meeting Abstract C1 Univ Calif San Francisco, San Francisco, CA 94143 USA. Univ Med & Dent New Jersey, Newark, NJ 07103 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. VA Med Ctr, E Orange, NJ USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3620 BP 686 EP 687 PG 2 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103614 ER PT J AU Olin, KL Krauss, RM La Belle, M Hokanson, JE Wight, TN Chait, A AF Olin, KL Krauss, RM La Belle, M Hokanson, JE Wight, TN Chait, A TI ApoCIII modulates lipoprotein binding to the vascular proteoglycan, biglycan SO CIRCULATION LA English DT Meeting Abstract C1 Univ Washington, Seattle, WA 98195 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3658 BP 693 EP 694 PG 2 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103652 ER PT J AU Marathe, S Tribble, DL Kuriakose, G La Belle, M Chu, BM Gong, EL Johns, A Williams, KJ Tabas, I AF Marathe, S Tribble, DL Kuriakose, G La Belle, M Chu, BM Gong, EL Johns, A Williams, KJ Tabas, I TI Sphingomyelinase (SMase) transgenic and knockout mice: Direct evidence that SMase is atherogenic in vivo SO CIRCULATION LA English DT Meeting Abstract C1 Columbia Univ, New York, NY USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. Berlex Bioscis, Richmond, CA USA. Thomas Jefferson Univ, Philadelphia, PA 19107 USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 3665 BP 695 EP 695 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417103659 ER PT J AU Superko, HR Krauss, RM AF Superko, HR Krauss, RM TI Non-high density lipoprotein cholesterol does not reflect the presence of small LDL pattern B SO CIRCULATION LA English DT Meeting Abstract C1 Berkeley HeartLab, San Mateo, CA USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 4226 BP 801 EP 801 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417104218 ER PT J AU Marshall, RC Powers-Risius, P Huesman, MK Taylor, SE Reutter, BW Schustz, AM AF Marshall, RC Powers-Risius, P Huesman, MK Taylor, SE Reutter, BW Schustz, AM TI Quantitative assessment of reperfusion following severe ischemic injury in isolated rabbit heart SO CIRCULATION LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 2 PY 1999 VL 100 IS 18 SU S MA 4573 BP 866 EP 866 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 250YD UT WOS:000083417104563 ER PT J AU Gracias, DH Chen, Z Shen, YR Somorjai, GA AF Gracias, DH Chen, Z Shen, YR Somorjai, GA TI Molecular characterization of polymer and polymer blend surfaces. Combined sum frequency generation surface vibrational spectroscopy and scanning force microscopy studies SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID STRETCHING MODES; POLYETHYLENE; POLYPROPYLENE; MODULUS C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Gracias, David/A-1942-2010; Chen, Zhan/G-8312-2016 OI Gracias, David/0000-0003-2735-4725; Chen, Zhan/0000-0001-8687-8348 NR 32 TC 83 Z9 84 U1 2 U2 27 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 NOV PY 1999 VL 32 IS 11 BP 930 EP 940 DI 10.1021/ar990034f PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 259CV UT WOS:000083877100003 ER PT J AU Terwilliger, TC AF Terwilliger, TC TI Reciprocal-space solvent flattening SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID DENSITY-MODIFICATION; PHASE PROBLEM; MACROMOLECULAR CRYSTALLOGRAPHY; COMBINING CONSTRAINTS; MAXIMUM-ENTROPY; IMPROVEMENT; EXTENSION; REFINEMENT; RESOLUTION; HISTOGRAM AB Solvent flattening is a powerful tool for improving crystallographic phases for macromolecular structures obtained at moderate resolution, but uncertainties in the optimal weighting of experimental phases and modified phases make it difficult to extract all the phase information possible. Solvent flattening is essentially an iterative method for maximizing a likelihood function which consists of (i) experimental phase information and (ii) information on the likelihood of various arrangements of electron density in a map, but the likelihood function is generally not explicitly defined. In this work, a procedure is described for reciprocal-space maximization of a likelihood function based on experimental phases and characteristics of the electron-density map. The procedure can readily be applied to phase improvement based on solvent flattening and can potentially incorporate information on a wide variety of other characteristics of the electron-density map. C1 Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Los Alamos, NM 87545 USA. RP Terwilliger, TC (reprint author), Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Mail Stop M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 30 TC 172 Z9 176 U1 0 U2 12 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 NOV PY 1999 VL 55 BP 1863 EP 1871 DI 10.1107/S0907444999010033 PN 11 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 260LE UT WOS:000083951500013 PM 10531484 ER PT J AU Terwilliger, TC Berendzen, J AF Terwilliger, TC Berendzen, J TI Evaluation of macromolecular electron-density map quality using the correlation of local r.m.s. density SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID SHAKE-AND-BAKE; CRYSTALLOGRAPHY; IMPROVEMENT; RESOLUTION; HISTOGRAM; EXTENSION AB It has recently been shown that the standard deviation of local r.m.s. electron density is a good indicator of the presence of distinct regions of solvent and protein in macromolecular electron-density maps here, it is demonstrated that a complementary measure, the correlation of local r.m.s. density in adjacent regions on the unit cell, is also a good measure of the presence of distinct solvent and protein regions. The correlation of local r.m.s. density is essentially a measure of how contiguous the solvent (and protein) regions are in the electron-density map. This statistic can be calculated in real space or in reciprocal space and has potential uses in evaluation of heavy-atom solutions in the MIR and MAD methods as well as for evaluation of trial phase sets in ab initio phasing procedures. C1 Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Terwilliger, TC (reprint author), Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Mail Stop M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 23 TC 60 Z9 60 U1 0 U2 3 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 NOV PY 1999 VL 55 BP 1872 EP 1877 DI 10.1107/S090744499901029X PN 11 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 260LE UT WOS:000083951500014 PM 10531485 ER PT J AU Weber, F AF Weber, F TI From Boson condensation to quark deconfinement: The many faces of neutron star interiors SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXIIIrd School of Theoretical Physics CY SEP 15-22, 1999 CL USTRON, POLAND SP Univ Silesia, Inst Phys, Fdn Polish German Collaborat, Polish St Comm Sci Res ID HEAVY-ION COLLISIONS; STRANGE STARS; GENERAL-RELATIVITY; REALISTIC EQUATIONS; KAON PRODUCTION; NUCLEON MATTER; MASS; CONSTRAINTS; DIBARYONS; DENSITY AB Gravity compresses the matter in the cores of neutron stars to densities which are significantly higher than the density of ordinary atomic nuclei, thus providing a high-pressure environment in which numerous particle processes - from the generation of new baryonic particles to quark deconfinement to the formation of Boson condensates and H-matter - may compete with each other. There are theoretical suggestions of even more 'exotic' processes inside pulsars, such as the formation of absolutely stable strange quark matter, a configuration of matter even more stable than the most stable atomic nucleus, iron. In the latter event, neutron stars would be largely composed of pure quark matter, eventually enveloped in nuclear crust matter. No matter which physical processes are actually realized inside neutron stars, each one leads to fingerprints, some more pronounced than others though, in the observable stellar quantities. This feature combined with the tremendous recent progress in observational radio and X-ray astronomy, renders neutron stars to nearly ideal probes for a wide range of dense matter studies, complementing the quest of the behavior of superdense matter in terrestrial collider experiments. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Nucl Sci Div, Berkeley, CA 94720 USA. RP Weber, F (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Nucl Sci Div, MS 70A-3307, Berkeley, CA 94720 USA. NR 82 TC 13 Z9 14 U1 0 U2 0 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD NOV PY 1999 VL 30 IS 11 BP 3149 EP 3169 PG 21 WC Physics, Multidisciplinary SC Physics GA 277UR UT WOS:000084952400007 ER PT J AU Harlander, R AF Harlander, R TI Asymptotic expansions - Methods and applications SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXIIIrd School of Theoretical Physics CY SEP 15-22, 1999 CL USTRON, POLAND SP Univ Silesia, Inst Phys, Fdn Polish German Collaborat, Polish St Comm Sci Res ID MINIMAL SUBTRACTION SCHEME; 2-LOOP QCD CORRECTIONS; OPERATOR EXPANSIONS; FEYNMAN DIAGRAMS; ZERO RECOIL; O(ALPHA(2)(S)) CORRECTIONS; B->C TRANSITIONS; MASS CORRECTIONS; GREEN-FUNCTIONS; STANDARD MODEL AB Different viewpoints on the asymptotic expansion of Feynman diagrams are reviewed. The relations between the field theoretic and diagrammatic approaches are sketched. The focus is on problems with large masses or large external momenta. Several recent applications also for other limiting cases are touched upon. Finally, the pros and cons of the different approaches are briefly discussed. C1 Brookhaven Natl Lab, Dept Phys, HET, Upton, NY 11973 USA. RP Harlander, R (reprint author), Brookhaven Natl Lab, Dept Phys, HET, Upton, NY 11973 USA. NR 66 TC 8 Z9 8 U1 0 U2 0 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD NOV PY 1999 VL 30 IS 11 BP 3443 EP 3462 PG 20 WC Physics, Multidisciplinary SC Physics GA 277UR UT WOS:000084952400027 ER PT J AU Alvin, KF Park, KC AF Alvin, KF Park, KC TI Extraction of substructural flexibility from global frequencies and mode shapes SO AIAA JOURNAL LA English DT Article ID STRUCTURAL DAMAGE DETECTION; STIFFNESS; ALGORITHM; MATRICES AB A computational procedure for extracting substructure-by-substructure flexibility properties from global modal parameters is presented. The present procedure consists of two key features: an element-based direct flexibility method, which uniquely determines the global flexibility without resorting to case-dependent redundancy selections, and the projection of kinematically inadmissible modes that are contained in the iterated substructural matrices. The direct flexibility. method is used as the basis of an inverse problem, whose goal is to determine substructural flexibilities given the global flexibility; geometrically determined substructural rigid-body modes, and the local to global assembly operators. The resulting procedure, given accurate global flexibility, extracts the exact element-by-element substructural flexibilities for determinate structures. For indeterminate structures, the accuracy depends on the iteration tolerance limits. The procedure is illustrated using both simple and complex numerical examples and appears to be effective for structural applications such as damage localization and finite element model reconciliation. C1 Sandia Natl Labs, Struct Dynam & Vibrat Control Dept, Albuquerque, NM 87185 USA. Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Univ Colorado, Ctr Aerosp Struct, Boulder, CO 80309 USA. RP Alvin, KF (reprint author), Sandia Natl Labs, Struct Dynam & Vibrat Control Dept, POB 5800, Albuquerque, NM 87185 USA. RI park, k.c./E-8898-2010 NR 25 TC 11 Z9 12 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD NOV PY 1999 VL 37 IS 11 BP 1444 EP 1451 DI 10.2514/2.621 PG 8 WC Engineering, Aerospace SC Engineering GA 255AM UT WOS:000083647400013 ER PT J AU Hu, MZC Reeves, M AF Hu, MZC Reeves, M TI Ligand-grafted biomaterials for adsorptive separations of uranium in solution SO AICHE JOURNAL LA English DT Article ID DI(2-ETHYLHEXYL)PHOSPHORIC ACID HDEHP; POLYURETHANE FOAM SORBENTS; LANTHANIDE ELEMENTS; HEAVY-METALS; CELL-WALLS; EXTRACTION; COMPLEXES; ACTINIDE; MEDIA; NITROBENZENE AB Many organic molecules, particularly biologicals, contain functional groups (ligands) that actively interact with metal ions in solution by adsorption, ion exchange, or chelation/coordination/complexation. Water-soluble organics have limitations as reagents for metal-ion separations from aqueous solutions. However, if the ligand molecule(s) are grafted on to an insoluble matrix the resulting ligand(s)-containing product becomes useful for separations applications related to metal recovery or remediation. It was discovered that biomolecules containing a primary amino group, secondary amino group, or hydroxyl group could be grafted into a polyurethane polymeric network via in situ polymerization reactions. With carboxyl groups, grafted material showed goon selectivity among a group of divalent metal cations, and a uranium-binding capacity of more than 10 mg/g of polymer. The material can be regenerated by sodium bicarbonate or sodium carbonate solution and reused. Data from a stirred-tank reactor showed fast uranium-binding kinetics, and breakthrough-elution studies with a packed-column reactor indicated promising process behavior. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Reeves, M (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. OI Hu, Michael/0000-0001-8461-9684 NR 62 TC 8 Z9 8 U1 0 U2 10 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD NOV PY 1999 VL 45 IS 11 BP 2333 EP 2345 DI 10.1002/aic.690451109 PG 13 WC Engineering, Chemical SC Engineering GA 254PD UT WOS:000083620600008 ER PT J AU Sultan, M Fiske, M Stein, T Gamal, M Hady, YA El Araby, H Madani, A Mehanee, S Becker, R AF Sultan, M Fiske, M Stein, T Gamal, M Hady, YA El Araby, H Madani, A Mehanee, S Becker, R TI Monitoring the urbanization of the Nile Delta, Egypt SO AMBIO LA English DT Article; Proceedings Paper CT World Conference on Science CY JUN 26, 1999 CL BUDAPEST, HUNGARY SP UNESCO, ICSU AB Comparisons of processed and coregistered digital mosaics of LANDSAT MSS and TM scenes, acquired over the Nile Delta in 1972, 1984, and 1990, indicate that urban growth is endangering Egypt's agricultural productivity. Urban areas occupied a minimum of 3.6%, 4.7%, and 5.7% of the Nile Delta in 1972, 1984, and 1990, respectively, an increase of 58% in 18 years. Approximately half of this increase occurred between 1984 and 1990. If this trend continues, Egypt could lose 12% of its total agricultural area to urbanization by 2010. Despite the fact that growth is pronounced around the cities, it is the growth around the thousands of small villages that poses the largest threat to the agricultural productivity of the Nile Delta. The cumulative growth rate for the cities and large villages between 1972 acid 1990 is 37%, and that for the small villages is 77% for the same time period. C1 Argonne Natl Lab, Div Environm Res, Int Programs, Argonne, IL 60439 USA. Cairo Univ, Dept Geophys, Cairo, Egypt. Univ Illinois, Dept Earth & Environm Sci, Chicago, IL USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Cairo Univ, Ctr Environm Hazard Mitigat, Giza, Egypt. RP Sultan, M (reprint author), Argonne Natl Lab, Div Environm Res, Int Programs, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Becker, Richard/A-9120-2010; Madani, Ahmed/K-5892-2012 OI Becker, Richard/0000-0003-2514-2040; NR 4 TC 7 Z9 7 U1 1 U2 4 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0044-7447 J9 AMBIO JI Ambio PD NOV PY 1999 VL 28 IS 7 BP 628 EP 631 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 267KM UT WOS:000084357200011 ER PT J AU Anovitz, LM Blencoe, JG AF Anovitz, LM Blencoe, JG TI Dry melting of high albite SO AMERICAN MINERALOGIST LA English DT Article ID SILICATE MELTS; HIGH-PRESSURE; MINERAL GLASSES; CARBON-DIOXIDE; WATER MELTS; MODEL; NAALSI3O8; LIQUIDS; MAGMAS; SPECTROSCOPY AB The properties of albitic melts are central to thermodynamic models for synthetic and natural granitic liquids. We have analyzed published phase-equilibrium and thermodynamic data for the dry fusion of high albite to develop a more accurate equation for the Gibbs free energy of this reaction to 30 kbar and 1400 degrees C. Strict criteria for reaction reversal were used to evaluate the phase-equilibrium data, and the thermodynamic properties of solid and liquid albite were evaluated using the published uncertainties in the original measurements. Results suggest that neither available phase-equilibrium experiments nor thermodynamic data tightly constrain the location of the reaction. Experimental solidus temperatures at 1 atm range from 1100 to 1120 degrees C. High-pressure experiments were not reversed completely and may have been affected by several sources of error, but the apparent inconsistencies among the results of the various experimentalists are eliminated when only half-reversal data are considered. Uncertainties in thermodynamic data yield large variations in permissible reaction slopes. Disparities between experimental and calculated melting curves are, therefore, largely attributable to these difficulties, and there is no fundamental disagreement between the available phase-equilibrium and thermodynamic data for the dry melting of albite. Consequently, complex speciation models for albitic melts, based on the assumption that these discrepancies represent a real characteristic of the system, are unjustified at this time. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Geochem Grp, Oak Ridge, TN 37831 USA. RP Anovitz, LM (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Geochem Grp, Oak Ridge, TN 37831 USA. RI Anovitz, Lawrence/P-3144-2016 OI Anovitz, Lawrence/0000-0002-2609-8750 NR 73 TC 12 Z9 13 U1 0 U2 2 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD NOV-DEC PY 1999 VL 84 IS 11-12 BP 1830 EP 1842 PG 13 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 254AB UT WOS:000083588400010 ER PT J AU Ni, J Lipert, RJ Dawson, GB Porter, MD AF Ni, J Lipert, RJ Dawson, GB Porter, MD TI Immunoassay readout method using extrinsic Raman labels adsorbed on immunogold colloids SO ANALYTICAL CHEMISTRY LA English DT Article ID PHOTOTHERMAL DEFLECTION SPECTROSCOPY; ENZYME-IMMUNOASSAY; GOLD ELECTRODES; SURFACE; AU; SCATTERING; SERUM; NANOPARTICLES; ANTIGEN; SYSTEM AB An immunoassay readout method based on surface-enhanced Raman scattering (SERS) is described. The method exploits the SERS-derived signal from reporter molecules that are coimmobilized with biospecific species on gold colloids. This concept is demonstrated in a dual-analyte sandwich assay, in which two different antibodies covalently bound to a solid substrate specifically capture two different antigens from an aqueous sample. The captured antigens in turn bind selectively to their corresponding detection antibodies. The detection antibodies are conjugated with gold colloids that are labeled with different Raman reporter molecules, which serve as extrinsic labels for each type of antibody. The presence of a specific antigen is established by the characteristic SERS spectrum of the reporter molecule. A near-infrared diode laser was used to excite efficiently the SERS signal while minimizing fluorescence interference. We show that, by using different labels with little spectral overlap, two different antigenic species can be detected simultaneously. The potential of this concept to function as a readout strategy for multiple analytes is briefly discussed. C1 US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Porter, MD (reprint author), US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. RI Lipert, Robert/A-8571-2009 NR 42 TC 363 Z9 374 U1 11 U2 114 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 1999 VL 71 IS 21 BP 4903 EP 4908 DI 10.1021/ac990616a PG 6 WC Chemistry, Analytical SC Chemistry GA 252EX UT WOS:000083490100041 PM 10565281 ER PT J AU Gong, XY Yeung, ES AF Gong, XY Yeung, ES TI An absorption detection approach for multiplexed capillary electrophoresis using a linear photodiode array SO ANALYTICAL CHEMISTRY LA English DT Article ID ZONE-ELECTROPHORESIS; SEPARATION AB A novel absorption detection method for highly multiplexed capillary electrophoresis is presented for zone electrophoresis and for micellar electrokinetic chromatography. The approach involves the use of a linear photodiode array on which a capillary array is imaged by a camera lens. Either a tungsten lamp or a mercury lamp can be used as the light source such that all common wavelengths for absorption detection are accessible by simply interchanging narrow-band filters. Each capillary spans several diodes in the photodiode array for absorption measurements. Over 100 densely packed capillaries can be monitored by a single photodiode array element with 1024 diodes. The detection limit for rhodamine 6G for each capillary in the multiplexed array is similar to 1.8 x 10(-8) M injected (S/N = 2). The cross-talk between adjacent capillaries is less than 0.2%. Simultaneous analysis of 96 samples is demonstrated. C1 Iowa State Univ Sci & Technol, Ames Lab, USDOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), Iowa State Univ Sci & Technol, Ames Lab, USDOE, Ames, IA 50011 USA. NR 20 TC 62 Z9 62 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 1999 VL 71 IS 21 BP 4989 EP 4996 DI 10.1021/ac9900634 PG 8 WC Chemistry, Analytical SC Chemistry GA 252EX UT WOS:000083490100055 PM 21662842 ER PT J AU Fox, NJ Cowley, SWH Davda, VN Enno, G Friis-Christensen, E Greenwald, RA Hairston, MR Lester, M Lockwood, M Luhr, H Milling, DK Murphree, JS Pinnock, M Reeves, GD AF Fox, NJ Cowley, SWH Davda, VN Enno, G Friis-Christensen, E Greenwald, RA Hairston, MR Lester, M Lockwood, M Luhr, H Milling, DK Murphree, JS Pinnock, M Reeves, GD TI A multipoint study of a substorm occurring on 7 December, 1992, and its theoretical implications SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article DE ionosphere (auroral ionosphere; plasma; convection); magnetospheric physics (storms and substorms) ID ENERGETIC PARTICLE MEASUREMENTS; CONVECTION PATTERNS; MAGNETOSPHERE; IONOSPHERE; 6.6-RE; RADARS AB On 7 December 1992, a moderate substorm was observed by a variety of satellites and ground-based instruments. Ionospheric flows were monitored near dusk by the Goose Bay HF radar and near midnight by the EISCAT radar. The observed flows are compared here with magnetometer observations by the IMAGE array in Scandinavia and the two Greenland chains, the auroral distribution observed by Freja and the substorm cycle observations by the SABRE radar, the SAMNET magnetometer array and LANL geosynchronous satellites. Data from Galileo Earth-encounter II are used to estimate the IMF B-z component. The data presented show that the substorm onset electrojet at midnight was confined to closed field lines equatorward of the preexisting convection reversal boundaries observed in the dusk and midnight regions. No evidence of substantial closure of open flux was detected following this substorm onset. Indeed the convection reversal boundary on the duskside continued to expand equatorward after onset due to the continued presence of strong southward IMF, such that growth and expansion phase features were simultaneously present. Clear indications of closure of open flux were not observed until a subsequent substorm intensification 25 min after the initial onset. After this time, the substorm auroral bulge in the nightside hours propagated well poleward of the pre-existing convection reversal boundary, and strong flow perturbations were observed by the Goose Bay radar, indicative of flows driven by reconnection in the tail. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys, Leicester LE1 7RH, Leics, England. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. Danish Space Res Inst, DK-2100 Copenhagen, Denmark. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Texas, Richardson, TX 75080 USA. Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. British Antarctic Survey, Cambridge CB3 0ET, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fox, NJ (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Lockwood, Mike/G-1030-2011; Reeves, Geoffrey/E-8101-2011; Fox, Nicola/P-6692-2016; OI Lockwood, Mike/0000-0002-7397-2172; Reeves, Geoffrey/0000-0002-7985-8098; Fox, Nicola/0000-0003-3411-4228; Hairston, Marc/0000-0003-4524-4837; Greenwald, Raymond/0000-0002-7421-5536 NR 31 TC 14 Z9 14 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD NOV PY 1999 VL 17 IS 11 BP 1369 EP 1384 DI 10.1007/s005850050863 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 259DE UT WOS:000083878000002 ER PT J AU Smolyansky, SA Prozorkevich, AV Maino, G Mashnik, SG AF Smolyansky, SA Prozorkevich, AV Maino, G Mashnik, SG TI A covariant generalization of the real-time Green's functions method in the theory of kinetic equations SO ANNALS OF PHYSICS LA English DT Article ID RELATIVISTIC TRANSPORT-THEORY; HARTREE-FOCK APPROXIMATION; NUCLEAR-MATTER; VLASOV-TYPE; HADRONIC MATTER; HADRODYNAMICS; EXPANSIONS; COLLISIONS; FREEDOM; MODEL AB A generalized quantum relativistic kinetic equation (RKE) of the Kadanoff-Baym type is obtained on the basis of the Heisenberg equations of motion where the time evolution and space translation are separated From each other by means of the covariant method. The same approach is used also for a covariant modification of the real-time Green's Functions method based on the Wigner representation. The suggested approach does not contain arbitrariness' elements and uncertainties which often arise from derivation of RKE on the basis of the motion equations of the Kadanoff-Baym type for the correlation functions in the case of systems with inner degrees of freedom. Possibilities of the proposed method are demonstrated by examples of derivation of RKE of the Vlasov type and collision integrals of the Boltzmann-Uehling-Uhienbeck (BUU) type in the Frame of the oo-version of quantum hadrodynamics, for the simplest case of spin saturated nuclear matter without antinuclear component. Here. the quasiparticle approximation in a covariant performance is used. A generalization of the method for the description of strong non-equilibrium slates based on the non-equilibrium statistical operator is then proposed as well. (C) 1999 Academic Press. C1 Saratov State Univ, Dept Phys, Saratov 410071, Russia. ENEA, Div Appl Phys, I-40129 Bologna, Italy. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Smolyansky, SA (reprint author), Saratov State Univ, Dept Phys, Saratov 410071, Russia. RI Maino, Giuseppe/D-4628-2015 OI Maino, Giuseppe/0000-0002-6514-908X NR 57 TC 9 Z9 9 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD NOV 1 PY 1999 VL 277 IS 2 BP 193 EP 218 DI 10.1006/aphy.1999.5954 PG 26 WC Physics, Multidisciplinary SC Physics GA 256CP UT WOS:000083708600003 ER PT J AU Wise, MG McArthur, JV Shimkets, LJ AF Wise, MG McArthur, JV Shimkets, LJ TI Methanotroph diversity in landfill soil: Isolation of novel type I and type II methanotrophs whose presence was suggested by culture-independent 16S ribosomal DNA analysis SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID PARTICULATE METHANE MONOOXYGENASE; GRADIENT GEL-ELECTROPHORESIS; FUNCTIONAL GENE PROBE; SPRING MICROBIAL MAT; PHYLOGENETIC ANALYSIS; RNA ANALYSIS; TRICHLOROETHYLENE OXIDATION; FAMILY METHYLOCOCCACEAE; METHYLOTROPHIC BACTERIA; MAXIMUM-LIKELIHOOD AB The diversity of the methanotrophic community in mildly acidic landfill cover soil was assessed by three methods: two culture-independent molecular approaches and a traditional culture-based approach. For the first of the molecular studies, two primer pairs specific for the 16S rRNA gene of validly published type I (including the former type X) and type II methanotrophs were identified and tested. These primers were used to amplify directly extracted soil DNA, and the products were used to construct type I and type LT clone libraries. The second molecular approach, based on denaturing gradient gel electrophoresis (DGGE), provided profiles of the methanotrophic community members as distinguished by sequence differences in variable region 3 of the 16S ribosomal DNA. For the culturing studies, an extinction-dilution technique was employed to isolate slow-growing but numerically dominant strains. The key variables of the series of enrichment conditions were initial pH (4.8 versus 6.8), air/CH4/CO2 headspace ratio (50:45:5 versus 90:9:1), and concentration of the medium (1x nitrate minimal salts [NMS] versus 0.2x NMS). Screening of the isolates showed that the nutrient-rich Ix NMS selected for type I methanotrophs, while the nutrient-poor 0.2 x NMS tended to enrich for type II methanotrophs. Partial sequencing of the 16S rRNri gene from selected clones and isolates revealed some of the same novel sequence types. Phylogenetic analysis of the type I clone library suggested the presence of a new phylotype related to the Methylobacter-Methylomicrobium group, and this was confirmed by isolating two members of this cluster, The type II clone library also suggested the existence of a novel group of related species distinct from the validly published Methylosinus and Methylocystis genera, and two members of this cluster were also successfully cultured. Partial sequencing of the pmoA gene, which codes for the 27-kDa polypeptide of the particulate methane monooxygenase, reaffirmed the phylogenetic placement of the four isolates. Finally, not all of the bands separated by DGGE could be accounted for by the clones and isolates. This polyphasic assessment of community structure demonstrates that much diversity among the obligate methane oxidizers has yet to be formally described. C1 Univ Georgia, Dept Microbiol, Athens, GA 30602 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Shimkets, LJ (reprint author), Univ Georgia, Dept Microbiol, 527 Biol Sci Bldg, Athens, GA 30602 USA. NR 62 TC 129 Z9 138 U1 1 U2 27 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD NOV PY 1999 VL 65 IS 11 BP 4887 EP 4897 PG 11 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 252AQ UT WOS:000083478900026 PM 10543800 ER PT J AU Guo, XX Shi, DJ Xu, XD Ouyang, YS Ru, BG AF Guo, XX Shi, DJ Xu, XD Ouyang, YS Ru, BG TI Metal-induced expressing of mammal Metallothionein-1 gene in cyanobacteria to promote cadmium-binding preferences SO APPLIED MICROBIOLOGY AND BIOTECHNOLOGY LA English DT Article ID PROKARYOTIC METALLOTHIONEIN; LOCUS AB The metal(zinc)-inducible smtA gene promoter (smt O-P) from cyanobacteria was applied for the expression of mouse MT-1 cDNA in the filamentous cyanobacterium Anabaena sp. PCC 7120 to enhance its metal-binding capability and to change its main binding specificity from zinc to cadmium. Shuttle expression vector pKT-MRE transformed the cyanobacterial cells by triparent conjugal transfer. Positive clones were screened and identified by streptomycin, DNA dot blot, SDS-PAGE and Western blot analysis. Photosynthetic oxygen evolution and metal atom absorption indicated that under the cadmium stress the metal-induced expression of foreign mMT-1 doubled their cadmium resistance and developed cells showing a much higher preference to absorb cadmium other than zinc in medium. The cadmium content in cell extract rose from 11% to 36%, and the cadmium cleared from media by transgenic cells rose from 18% to 62%. There was only a slight enhancement for zinc binding in the wild or transgenic type. C1 Chinese Acad Sci, Inst Bot, Res Ctr Photosynth, Beijing 100093, Peoples R China. Peking Univ, Natl Lab Prot & Plant Genet Engn, Beijing 100871, Peoples R China. Michigan State Univ, US DOE, MSU, Plant Res Lab, E Lansing, MI 48824 USA. RP Shi, DJ (reprint author), Chinese Acad Sci, Inst Bot, Res Ctr Photosynth, Beijing 100093, Peoples R China. NR 16 TC 5 Z9 16 U1 1 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0175-7598 J9 APPL MICROBIOL BIOT JI Appl. Microbiol. Biotechnol. PD NOV PY 1999 VL 52 IS 6 BP 806 EP 810 PG 5 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 261KJ UT WOS:000084008100011 ER PT J AU Kowalski, MP Barbee, TW Heidemann, KF Gursky, H Rife, JC Hunter, WR Fritz, GG Cruddace, RG AF Kowalski, MP Barbee, TW Heidemann, KF Gursky, H Rife, JC Hunter, WR Fritz, GG Cruddace, RG TI Efficiency calibration of the first multilayer-coated holographic ion-etched flight grating for a sounding rocket high-resolution spectrometer SO APPLIED OPTICS LA English DT Article ID WAVELENGTH REGION; CRYSTAL MONOCHROMATOR; PERFORMANCE AB We have fabricated the four flight gratings for a sounding rocket high-resolution spectrometer using a holographic ion-etching technique. The gratings are spherical (4000-mm radius of curvature), large (160 mm x 90 mm), and have a laminar groove profile of high density (3600 grooves/mm). They have been coated with a high-reflectance multilayer of Mo/Si. Using an atomic force microscope, we examined the surface characteristics of the first grating before and after multilayer coating. The average roughness is approximately 3 Angstrom rms after coating. Using synchrotron radiation, we completed an efficiency calibration map over the wavelength range 225-245 Angstrom. At an angle of incidence of 5 degrees and a wavelength of 234 Angstrom, the average efficiency in the first inside order is 10.4 +/- 0.5%, and the derived groove efficiency is 34.8 +/- 1.6%. These values exceed all previously published results for a high-density grating. (C) 1999 Optical Society of America. OCIS codes: 050.1950, 120.6200, 120.6660, 260.7200, 310.1620, 350.1260. C1 USN, Res Lab, Washington, DC 20375 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Carl Zeiss, D-73446 Oberkochen, Germany. SFA Inc, Largo, MD 20774 USA. RP Kowalski, MP (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 14 TC 21 Z9 21 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 NOV 1 PY 1999 VL 38 IS 31 BP 6487 EP 6493 DI 10.1364/AO.38.006487 PG 7 WC Optics SC Optics GA 253LF UT WOS:000083557500003 PM 18324179 ER PT J AU Rubel, GO Fung, KH AF Rubel, GO Fung, KH TI Influence of saline media on the fluorescence emission of Bacillus spores SO APPLIED OPTICS LA English DT Article AB Single-particle levitation in conjunction with 264.3-nm laser excitation is used to measure the fluorescence emission of individual particles of Bacillus globigii spores. With precise humidity control, the fluorescence emission of wetted and desiccated Bacillus spore particles is measured from 300 to 450 nm. Comparison of spectra for Bacillus spores suspended in a standard buffer aqueous solution and for a desiccated 10-mu m-diameter aggregate Bacillus spore particle shows that the spectra is virtually indistinguishable. However, at 85% relative humidity, corresponding to a 4.5M sodium chloride solution, the spore spectra redshifts by approximately 25 nm. It is postulated that the spectra redshifting is a result of specific interactions between the tyrosine fluorophore of the Bacillus spore and the phosphate moieties in the buffer solution. (C) 1999 Optical Society of America. C1 Soldier Biol Chem Command, Edgewood Chem Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. Brookhaven Natl Lab, Dept Adv Technol, Global Secur Div, Upton, NY 11973 USA. RP Rubel, GO (reprint author), Soldier Biol Chem Command, Edgewood Chem Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. EM gxrubel@sbccom.apgea.army.mil NR 6 TC 0 Z9 0 U1 0 U2 0 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 NOV 1 PY 1999 VL 38 IS 31 BP 6673 EP 6676 DI 10.1364/AO.38.006673 PG 4 WC Optics SC Optics GA 253LF UT WOS:000083557500028 PM 18324204 ER PT J AU Fan, X Dickey, EC Pennycook, SJ Sunkara, MK AF Fan, X Dickey, EC Pennycook, SJ Sunkara, MK TI Z-contrast imaging and electron energy-loss spectroscopy analysis of chromium-doped diamond-like carbon films SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSITION-METALS; CRYSTALS; 3D AB Metal-doped diamond-like carbon films were produced for the purpose of an electrochemical nanoelectrode. In this study we use Z-contrast scanning transmission electron microscopy to directly observe metal cluster formation and distributions within the chromium-doped carbon films. At low doping (similar to 6 at. % Cr), Cr is uniformly distributed within the C matrix; at high doping (similar to 12 at. % Cr), Cr-rich clusters are formed. Analyzing electron energy loss spectroscopy Cr L-2,L-3 white line ratios, we find that the Cr tends to be metallic-like when it is uniformly distributed in the C matrix and carbide-like in the Cr-rich clusters. The carbon is more diamond-like at low doping and more graphite/carbide-like at high doping according to the sp(2)/sp(3) electron percentage measurements. (C) 1999 American Institute of Physics. [S0003-6951(99)00844-X]. C1 Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Louisville, Dept Chem Engn, Louisville, KY 40292 USA. RP Dickey, EC (reprint author), Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. RI Sunkara, Mahendra/A-3033-2008; Dickey, Elizabeth/A-3368-2011 OI Dickey, Elizabeth/0000-0003-4005-7872 NR 15 TC 33 Z9 33 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 1 PY 1999 VL 75 IS 18 BP 2740 EP 2742 DI 10.1063/1.125134 PG 3 WC Physics, Applied SC Physics GA 248VB UT WOS:000083295500012 ER PT J AU Yoon, M Larson, BC Tischler, JZ Haynes, TE Chung, JS Ice, GE Zschack, P AF Yoon, M Larson, BC Tischler, JZ Haynes, TE Chung, JS Ice, GE Zschack, P TI Use of x-ray microbeams for cross-section depth profiling of MeV ion-implantation-induced defect clusters in Si SO APPLIED PHYSICS LETTERS LA English DT Article ID DIFFUSE-SCATTERING; TEMPERATURE; SILICON; LOOPS AB We have used submicron-resolution synchrotron x-ray beams to study the size, type, and depth distribution of ion-implantation-induced defect clusters in Si. A 0.65 mu m resolution x-ray beam, generated using Fresnel zone plate focusing optics, was used to study (001)-oriented Si implanted at 300 degrees C with 10 MeV Si ions. Diffuse scattering measurements were made near the (220) Bragg reflection, as a function of depth on a (110) cross-sectioned sample, with a 0.65 mu m depth resolution. The microbeam focusing optics and the depth-resolved scattering measurements are discussed, and an analysis of the intensity and lineshape of the diffuse scattering is presented in terms of existing models of vacancy and interstitial clusters in Si. (C) 1999 American Institute of Physics. [S0003-6951(99)03144-7]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Illinois, Mat Res Lab, Argonne, IL 60439 USA. RP Yoon, M (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Haynes, Tony/P-8932-2015 OI Haynes, Tony/0000-0003-2871-4745 NR 13 TC 21 Z9 21 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 NOV 1 PY 1999 VL 75 IS 18 BP 2791 EP 2793 DI 10.1063/1.125151 PG 3 WC Physics, Applied SC Physics GA 248VB UT WOS:000083295500029 ER PT J AU Tanzer, TA Bohn, PW Roshchin, IV Greene, LH Klem, JF AF Tanzer, TA Bohn, PW Roshchin, IV Greene, LH Klem, JF TI Near-surface electronic structure on InAs(100) modified with self-assembled monolayers of alkanethiols SO APPLIED PHYSICS LETTERS LA English DT Article ID RAMAN-SPECTROSCOPY; OPTICAL-DETECTION; GAAS-SURFACES; INAS; PASSIVATION; SCATTERING; ACCUMULATION; PROBE; BAND; INP AB Surface chemical modification is used to eliminate the problem of high surface recombination velocity and control surface band bending on InAs(100). Alkanethiols, RSH; R=CH3(CH2)(n), both neat and in ethanolic solutions, are used to passivate this surface against oxidation, as characterized by Raman scattering and x-ray photoelectron spectroscopy of the adsorbate-covered and bare surfaces. The magnitude of the interfacial band bending is obtained by analysis of Raman scattering from the unscreened longitudinal optical phonon, which arises from the near-surface charge accumulation region. Removing the native oxide with a Br-2:CH3OH chemomechanical etch reduces the surface band bending, but atmospheric oxidation increases band bending to its original level over several hours. In contrast, alkanethiol passivation of InAs(100) prevents band bending for periods of up to several weeks. (C) 1999 American Institute of Physics. [S0003-6951(99)03644-X]. C1 Univ Illinois, Dept Chem, Urbana, IL 61801 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Bohn, PW (reprint author), Univ Illinois, Dept Chem, Urbana, IL 61801 USA. RI Roshchin, Igor/I-5162-2012 NR 31 TC 31 Z9 31 U1 1 U2 9 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 NOV 1 PY 1999 VL 75 IS 18 BP 2794 EP 2796 DI 10.1063/1.125152 PG 3 WC Physics, Applied SC Physics GA 248VB UT WOS:000083295500030 ER PT J AU Bangalore, AS Demirgian, JC Boparai, AS Small, GW AF Bangalore, AS Demirgian, JC Boparai, AS Small, GW TI Effect of spectral resolution on pattern recognition analysis using passive Fourier transform infrared sensor data SO APPLIED SPECTROSCOPY LA English DT Article DE spectral resolution; qualitative analysis; remote sensing; Fourier transform infrared spectroscopy; pattern recognition ID PIECEWISE-LINEAR DISCRIMINANTS; AUTOMATED DETECTION; SPECTROMETRY; OPTIMIZATION; VAPOR AB The Fourier transform infrared (FT-IR) spectral data of two nerve agent simulants, diisopropyl methyl phosphonate (DIMP) and dimethyl methyl phosphonate (DMMP), are used as test cases to determine the spectral resolution that gives optimal pattern recognition performance. DIMP is used as the target analyte for detection, while DMMP is used to test the ability of the automated pattern recognition methodology to detect the analyte selectively, Interferogram data are collected by using a Midac passive FT-IR instrument. The methodology is based on the application of pattern recognition techniques to short segments of single-beam spectra obtained by Fourier processing the collected interferogram data. The work described in this article evaluates the effect of varying spectral resolution on the pattern recognition results. The objective is to determine the optimal spectral resolution to be used for data collection. The results of this study indicate that the data with a nominal spectral resolution of 16 cm(-1) provide sufficient selectivity to give pattern recognition results comparable to that obtained by using higher resolution data. We found that, while higher resolution does not increase selectivity sufficiently to provide better pattern recognition results, lower resolution decreases selectivity and degrades the pattern recognition results. These results can be used as guidelines to maximize detection sensitivity, to minimize the time needed for data collection, and to reduce data storage requirements. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Ohio Univ, Dept Chem, Ctr Intelligent Chem Instrumentat, Clipper Labs, Athens, OH 45701 USA. RP Bangalore, AS (reprint author), ChemIcon Inc, 7301 Penn Ave, Pittsburgh, PA 15208 USA. NR 19 TC 8 Z9 8 U1 0 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD NOV PY 1999 VL 53 IS 11 BP 1382 EP 1391 DI 10.1366/0003702991945722 PG 10 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 259ME UT WOS:000083897000013 ER PT J AU Siriwardane, RV Poston, JA Fisher, EP Shen, MS Miltz, AL AF Siriwardane, RV Poston, JA Fisher, EP Shen, MS Miltz, AL TI Decomposition of the sulfates of copper, iron (II), iron (III), nickel, and zinc: XPS, SEM, DRIFTS, XRD, and TGA study SO APPLIED SURFACE SCIENCE LA English DT Article DE transition metal oxide; fuel gas; copper ID GAS-SOLID REACTIONS; THERMAL-DECOMPOSITION; STRUCTURAL MODEL; MOVING BOUNDARY; TEMPERATURE; KINETICS; SORBENTS; OXIDE AB The bulk and surface characteristics during decomposition of the transition metal sulfates of copper, iron (II), iron (III), nickel, and zinc are investigated utilizing various spectroscopic techniques. An oxidized form of sulfur was detected on the surface during decomposition of all metal sulfate samples, except zinc sulfate. Surface characteristics were not necessarily representative of the bulk characteristics. Oxy-sulfate was observed with copper sulfate only. Lower decomposition temperatures were observed in vacuum as compared to those at atmospheric pressure. Uniform sulfur distribution was observed across sample cross sections. Analysis consisted of Scanning electron microscopy/X-ray microanalysis, X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis, and X-ray diffraction. (C) 1999 Published by Elsevier Science B.V. AU rights reserved. C1 US Dept Energy, Fed Energy Technol Ctr, Morgantown, WV 26507 USA. EG>SWV, Morgantown, WV 26507 USA. RP Siriwardane, RV (reprint author), US Dept Energy, Fed Energy Technol Ctr, POB 880,3610 Collins Ferry Rd, Morgantown, WV 26507 USA. NR 36 TC 78 Z9 80 U1 3 U2 39 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD NOV PY 1999 VL 152 IS 3-4 BP 219 EP 236 DI 10.1016/S0169-4332(99)00319-0 PG 18 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 265YC UT WOS:000084273000012 ER PT J AU Seinost, G Golde, WT Berger, BW Dunn, JJ Qiu, D Dunkin, DS Dykhuizen, DE Luft, BJ Dattwyler, RJ AF Seinost, G Golde, WT Berger, BW Dunn, JJ Qiu, D Dunkin, DS Dykhuizen, DE Luft, BJ Dattwyler, RJ TI Infection with multiple strains of Borrelia burgdorferi sensu stricto in patients with Lyme disease SO ARCHIVES OF DERMATOLOGY LA English DT Article ID FRAGMENT-LENGTH-POLYMORPHISM; INTERGENIC SPACER AMPLICONS; CLINICAL MANIFESTATIONS; OSPC; GARINII; PROTEIN; ANTIGEN; JAPAN; MICE AB Objective: To assess human skin biopsy specimens from erythema migrans lesions for the presence of infection with multiple strains of the lyme disease spirochete, Borrelia burgdorferi. Design: Skin biopsy specimens were obtained prospectively from patients with erythema migrans. To determine allelic differences and strain identification of B burgdorferi, the biopsy specimens were analyzed by cold single-strand conformation polymorphism of an amplified fragment of the outer surface protein C (ospC) gene. Further single-strand conformation polymorphism patterns of amplified ospC genes from culture isolates were compared with polymerase chain reaction products obtained directly from erythema migrans biopsy specimens. Setting: A private dermatology office and a university medical center outpatient department. Patients: Sixteen patients presenting with erythema migrans. Results: Two of the 16 patients in this cohort were infected with 2 B burgdorferi sensu stricto strains, as evidenced by 2 ospC alleles in their skin biopsy results. Conclusion: This is the first documented description of the existence of more than a single strain of B burgdorferi sensu stricto in a human specimen. C1 SUNY Stony Brook, Dept Med, Div Allergy, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Dermatol, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Ecol & Evolut, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Dattwyler, RJ (reprint author), SUNY Stony Brook, Dept Med, Div Allergy Clin Immunol, HSC 16T-040, Stony Brook, NY 11794 USA. OI Dattwyler, Raymond/0000-0002-1983-1301; Luft, Benjamin/0000-0001-9008-7004 NR 18 TC 25 Z9 27 U1 0 U2 3 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 USA SN 0003-987X J9 ARCH DERMATOL JI Arch. Dermatol. PD NOV PY 1999 VL 135 IS 11 BP 1329 EP 1333 DI 10.1001/archderm.135.11.1329 PG 5 WC Dermatology SC Dermatology GA 254CD UT WOS:000083593600004 PM 10566830 ER PT J AU Arena, SM Halbrook, RS Arenal, CA AF Arena, SM Halbrook, RS Arenal, CA TI Predicting starling chick carcass PCB concentrations from PCB concentrations in ingested animal matter SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID POLYCHLORINATED-BIPHENYLS; STURNUS-VULGARIS; TREE SWALLOWS; FOX RIVER; GREEN-BAY; REPRODUCTION; CONTAMINATION; WISCONSIN; TOXICITY; USA AB Preremediation studies at Crab Orchard National Wildlife Refuge (CONWR) revealed statistically significant accumulations of polychlorinated biphenyls (PCBs) and effects in starling chicks (Sturnus vulgaris) from contaminated sites, including decreased nest attentiveness, decreased hedging success, and an increase in chick mortality. Although the expected route of exposure for starling chicks is thought to be via diet, this has not: previously been documented at CONWR. The purpose of this study was to develop an equation to predict starling chick carcass PCB concentrations from PCB concentrations in ingested animal matter During 1995 and 1996, stomach contents from 14 and 22 starling chicks collected from contaminated and reference sites, respectively, were evaluated. Animal, plant, and mineral matter in the stomach contents were separated and animal matter from stomachs of individuals from the same nest were combined, dried, and percent dry weight calculated. Composite samples of animal matter were then analyzed for the presence of PCBs (Aroclor 1254). Stomach contents were primarily composed of animal matter (76%), and the percent animal matter in the stomachs did not differ significantly among locations (range = 38.4% to 100%). The mean PCB concentration in composite samples of animal matter from stomachs of chicks collected from contaminated sites (1.82 +/- 1.17 mg/kg) was significantly greater than the concentrations in composite samples from two reference locations (<0.24 mg/kg). PCB concentrations in stomach contents were correlated (Pearson correlation coefficient = 0.91, p < 0.005) with concentrations in carcasses of chicks from which the stomachs had been collected. The regression TC = 6.19 x X-1,X-398, where Y = starling chick carcass PCB concentration and X = starling stomach animal matter PCB concentration, indicated that PCB concentrations in consumed animal matter accounted for 82% of the variability in starling carcass concentrations. C1 So Illinois Univ, Cooperat Wildlife Res Lab, Carbondale, IL 62901 USA. Univ Illinois, Dept Vet Biosci, Urbana, IL 61802 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Halbrook, RS (reprint author), So Illinois Univ, Cooperat Wildlife Res Lab, Carbondale, IL 62901 USA. NR 29 TC 1 Z9 1 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD NOV PY 1999 VL 37 IS 4 BP 548 EP 553 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 246FC UT WOS:000083152900016 PM 10508904 ER PT J AU Cohen, MH Ogle, PM Tran, HD Goodrich, RW Miller, JS AF Cohen, MH Ogle, PM Tran, HD Goodrich, RW Miller, JS TI Polarimetry and unification of low-redshift radio galaxies SO ASTRONOMICAL JOURNAL LA English DT Review DE galaxies : active; galaxies : nuclei; polarization; quasars : general ID ACTIVE GALACTIC NUCLEI; HUBBLE-SPACE-TELESCOPE; HIGH-RESOLUTION MAPS; BROAD-LINE EMISSION; SEYFERT 2 GALAXIES; CYGNUS-A; OPTICAL SPECTROSCOPY; COMPLETE SAMPLE; 3.6 CM; POLARIZATION AB We have made high-quality measurements of the polarization spectra of 13 FR II radio galaxies and taken polarization images for II of these with the Keck telescopes. Seven of the eight narrow-line radio galaxies (NLRGs) are polarized, and six of the seven show prominent broad Balmer lines in polarized light. The broad lines are also weakly visible in total flux. Some of the NLRGs show bipolar regions with roughly circumferential polarization vectors, revealing a large reflection nebula illuminated by a central source. Our observations powerfully support the hidden quasar hypothesis for some NLRGs. According to this hypothesis, the continuum and broad lines are blocked by a dusty molecular torus, but can be seen by reflected, hence polarized, light. Classification as a NLRG, a broad-line radio galaxy (BLRG), or a quasar therefore depends on orientation. However, not all objects fit into this unification scheme. Our sample is biased toward objects known in advance to be polarized, but the combination of our results with the 1996 findings of Hill, Goodrich, & DePoy show that at least six out of a complete, volume and flux-limited sample of nine FR II NLRGs have broad lines, seen either in polarization or P alpha. The BLRGs in our sample range from 3C 382, which has a quasar-like spectrum, to the highly reddened IRAS source FSC 2217+259. This reddening sequence suggests a continuous transition from unobscured quasar to reddened BLRG to NLRG. Apparently the obscuring torus does not have a distinct edge. The BLRGs have polarization images that are consistent with a point source broadened by seeing and diluted by starlight. We do not detect extended nebular or scattered emission, perhaps because it is swamped by the nuclear source. Our starlight-corrected BLRG spectra can be explained with a two-component model: a quasar viewed through dust and quasar light scattered by dust. The direct flux is more reddened than the scattered flux, causing the polarization to rise steeply to the blue. Strong rotations of the electric vector position angle across Ha in 3C 227 and 3C 445 may be explained by systematic orbital motions in an equatorial broad-line region. C1 CALTECH, Pasadena, CA 91125 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Keck Observ, CARA, Kamuela, HI 96743 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Cohen, MH (reprint author), CALTECH, Pasadena, CA 91125 USA. EM mhc@astro.caltech.edu; pmo@space.mit.edu; tran@adcam.pha.jhu.edu; goodrich@keck.hawaii.edu; miller@ucolick.org NR 104 TC 69 Z9 69 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD NOV PY 1999 VL 118 IS 5 BP 1963 EP 1987 DI 10.1086/301074 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 264LB UT WOS:000084182800006 ER PT J AU Laurent-Muehleisen, SA Kollgaard, RI Feigelson, ED Brinkmann, W Siebert, J AF Laurent-Muehleisen, SA Kollgaard, RI Feigelson, ED Brinkmann, W Siebert, J TI The RGB sample of intermediate BL Lacertae objects SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : general; galaxies : active; radio continuum : galaxies; surveys; X-rays : galaxies ID ALL-SKY SURVEY; ACTIVE GALACTIC NUCLEI; MEDIUM-SENSITIVITY SURVEY; LAC OBJECTS; RADIO CONSTRAINTS; PARENT POPULATION; OPTICAL POLARIZATION; GALAXIES; CATALOG; MODELS AB Combining newly identified and previously known BL Lacertae objects from the ROSAT All-Sky Survey-Green Bank (RGB) catalog, we present a sample of 127 BL Lacertae objects, the largest ever derived from a single uniform survey. A complete sample of 33 objects brighter than O = 18.0 mag is also presented. These samples are compared to other known BL Lac samples and are generally found to exhibit properties intermediate between those of the previously disparate classes of high- and low-energy-peaked BL Lacertae objects (HBLs and LBLs, respectively). This result is most dramatic in the distribution of the X-ray to radio logarithmic flux ratios, where the KGB BL Lacertae objects are shown to peak precisely where the sharp dichotomy between the two subclasses was previously seen. The alpha(ro) versus alpha(ox) diagram also shows the RGB sample smoothly bridges the gap between the previously distinct subclasses of LBLs and HBLs. The range of broadband spectral energy distributions (SEDs) exhibited by the RGB objects also shows that, contrary to prior claims, searches based on relatively deep surveys cannot limit follow-up spectroscopy to targets with a narrow range of SEDs since BL Lacertae objects clearly constitute a homogeneous population with a wide range of SEDs. As in results based on the Einstein Extended Medium Sensitivity Survey (EMSS) and 1 Jy BL Lac samples, we find a weak but statistically significant correlation between the composite X-ray spectral index alpha(xox) and the radio-optical spectral index alpha(ro). This implies that the more LBL-like RGB BL Lacertae objects have secondary sources of X-ray emission, possibly from inverse Compton components. This result, in addition to other characteristics of the RGB sample, indicates that the simple unified scheme, which postulates that HBLs and LBLs differ solely by orientation, may be in need of revision. We also present both the X-ray and radio log N-log S distributions for which the competing HBL/LBL unification scenarios have differing predictions. The unknown effects of the triple flux limit inherent ill the RGB Complete sample makes quantitative analysis uncertain, but the characteristics of the RGB sample compare well both with results obtained from previous samples and with general theoretical predictions based on a simple Monte Carlo simulation. Our analysis indicates that the unimodal distribution of BL Lac properties found in the RGB sample likely reliably reflects the underlying population, while the bimodal distribution found in earlier studies arose primarily from observational selection effects. The presence of not only intermediate but also extreme HBL and LBL objects is the KGB survey's unique strength and offers clear avenues for future studies that can undoubtedly address the question of how HBLs and LBLs are related. C1 Univ Calif Davis, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Laurent-Muehleisen, SA (reprint author), Univ Calif Davis, 7000 E Ave, Livermore, CA 94550 USA. NR 80 TC 115 Z9 117 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1999 VL 525 IS 1 BP 127 EP 143 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251MR UT WOS:000083449900010 ER PT J AU Tripp, R Branch, D AF Tripp, R Branch, D TI Determination of the Hubble constant using a two-parameter luminosity correction for type Ia supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE distance scale; supernovae : general ID CEPHEID DISTANCE SCALE; METALLICITY; H-0; MAGNITUDES; GALAXIES AB In this paper, we make a comprehensive determination of the Hubble constant H-0 by using two parameters-the B-V color and the rate of decline Delta m(15)-to simultaneously standardize the luminosities of all nearby Cepheid-calibrated Type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a manner as possible in order to avoid systematic effects. A simultaneous chi(2) minimization yields a standardized absolute luminosity of the Cepheid-calibrated supernovae as well as the Hubble constant obtained from the more distant sample. With an adopted LMC distance modulus of 18.50, we find H-0 = 62 km s(-1) Mpc(-1) and a standardized absolute magnitude of -19.46. The sensitivity of H-0 to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty delta H-0, dominated by uncertainties in the primary distance indicators, is estimated to be 5 km s(-1) Mpc(-1). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Inst Nucl & Particle Phys, Berkeley, CA 94720 USA. Univ Oklahoma, Dept Phys & Astron, Norman, OK 73019 USA. RP Tripp, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Inst Nucl & Particle Phys, Berkeley, CA 94720 USA. NR 30 TC 63 Z9 64 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 NOV 1 PY 1999 VL 525 IS 1 BP 209 EP 214 DI 10.1086/307883 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251MR UT WOS:000083449900017 ER PT J AU Atkins, R Benbow, W Berley, D Chen, ML Coyne, DG Delay, RS Dingus, BL Dorfan, DE Ellsworth, RW Espinoza, C Evans, D Falcone, A Fleysher, L Fleysher, R Gisler, G Goodman, JA Haines, TJ Hoffman, CM Hugenberger, S Kelley, LA Leonor, I McConnell, M McCullough, JF McEnery, JE Miller, RS Mincer, AI Morales, MF Murray, MM Nemethy, P Ryan, JM Schneider, M Shen, B Shoup, A Sinnis, C Smith, AJ Sullivan, GW Thompson, TN Tumer, T Wang, K Wascko, MO Westerhoff, S Williams, DA Yang, T Yodh, GB AF Atkins, R Benbow, W Berley, D Chen, ML Coyne, DG Delay, RS Dingus, BL Dorfan, DE Ellsworth, RW Espinoza, C Evans, D Falcone, A Fleysher, L Fleysher, R Gisler, G Goodman, JA Haines, TJ Hoffman, CM Hugenberger, S Kelley, LA Leonor, I McConnell, M McCullough, JF McEnery, JE Miller, RS Mincer, AI Morales, MF Murray, MM Nemethy, P Ryan, JM Schneider, M Shen, B Shoup, A Sinnis, C Smith, AJ Sullivan, GW Thompson, TN Tumer, T Wang, K Wascko, MO Westerhoff, S Williams, DA Yang, T Yodh, GB TI TeV observations of Markarian 501 with the Milagrito water Cerenkov detector SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (Markarian 501); gamma rays : observations ID ACTIVE GALAXY MARKARIAN-421; PHOTONS AB The Milagrito water Cerenkov detector near Los Alamos, New Mexico, was operated as a sky monitor at energies of a few TeV between 1997 February and 1998 May, including the period of the strong, long-lasting 1997 flare of Markarian 501. Milagrito served as a rest run for the full Milagro detector. An event excess with a significance of 3.7 sigma from Markarian 501 was observed, in agreement with expectations. C1 Univ Utah, Salt Lake City, UT 84112 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Maryland, College Pk, MD 20742 USA. Natl Sci Fdn, Arlington, VA 22230 USA. Univ Calif Irvine, Irvine, CA 92697 USA. George Mason Univ, Fairfax, VA 22030 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Hampshire, Durham, NH 03824 USA. NYU, New York, NY 10003 USA. Univ Calif Riverside, Riverside, CA 92521 USA. RP Atkins, R (reprint author), Univ Utah, Salt Lake City, UT 84112 USA. OI Wascko, Morgan/0000-0002-8348-4447 NR 16 TC 21 Z9 21 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1999 VL 525 IS 1 BP L25 EP L28 DI 10.1086/312332 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251MT UT WOS:000083450000007 ER PT J AU Ogle, PM Cohen, MH Miller, JS Tran, HD Goodrich, RW Martel, AR AF Ogle, PM Cohen, MH Miller, JS Tran, HD Goodrich, RW Martel, AR TI Polarization of broad absorption line QSOs. I. A spectropolarimetric atlas SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atlases; polarization; quasars : absorption lines; quasars : general; techniques : polarimetric ID ACTIVE GALACTIC NUCLEI; QUASI-STELLAR OBJECTS; FE-II; KECK SPECTROPOLARIMETRY; WAVELENGTH DEPENDENCE; STATISTICAL BEHAVIOR; LOW-RESOLUTION; EMISSION-LINE; GALAXIES; REGIONS AB We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission-line polarization of BAL QSOs yield clues about their structure. We confirm that BAL QSOs are in general more highly polarized than non-BAL QSOs, consistent with a more equatorial viewing direction for the former than the latter. We have identified two new highly polarized QSOs in our sample (12321+1325 and 1333+2840). The polarization rises weakly to the blue in most objects, perhaps owing to scattering and absorption by dust particles. We find that a polarization increase in the BAL troughs is a general property of polarized BAL QSOs, indicating an excess of scattered light relative to direct light, and consistent with the unification of BAL QSOs and non-BAL QSOs. We have also discovered evidence of resonantly scattered photons in the red wing of the C IV broad emission lines of a few objects. In most cases, the broad emission lines have lower polarization and a different position angle than the continuum. The polarization characteristics of low-ionization BAL QSOs are similar to those of high-ionization BAL QSOs, suggesting a similar BAL wind geometry. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, UCO, Lick Observ, Santa Cruz, CA 95064 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. WM Keck Observ, Kamuela, HI 96743 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Ogle, PM (reprint author), MIT, Ctr Space Res, NE80-6095,77 Massachusetts Ave, Cambridge, MA 02139 USA. EM pmo@space.mit.edu NR 69 TC 116 Z9 116 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 1999 VL 125 IS 1 BP 1 EP 34 DI 10.1086/313272 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 264BZ UT WOS:000084161300001 ER PT J AU Derevianko, A Johnson, WR Cheng, KT AF Derevianko, A Johnson, WR Cheng, KT TI Non-dipole effects in photoelectron angular distributions for rare gas atoms SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID MULTIPOLE CORRECTIONS; LOW ENERGIES; APPROXIMATION; IONIZATION AB We present a theoretical study of O(ka) and O(k(2)a(2)) corrections to the dipole approximation in photoionization of rare gas atoms, where k is the magnitude of the photon wave vector and a is the radius of the ionized subshell. In the dipole approximation, the photoelectron angular distribution is characterized by the single parameter beta. The O(ka) corrections are characterized by two parameters gamma and delta, and the O(k(2)a(2)) corrections are characterized by three parameters lambda, mu, and nu, constrained by the relation lambda + mu + nu = 0 and a correction Delta beta to the dipole parameter beta. Formulas are given for the non-dipole parameters in terms of reduced matrix elements of electric and magnetic multipole operators. Tables and graphs of the seven angular distribution parameters, calculated in the relativistic independent-particle approximation (IPA), are given for electron energies ranging from 20 to 5000 eV for all 41 subshells of the rare gas atoms He, Ne, Ar, Kr, and Xe. Tables and graphs of the O(ka) parameters are also given in the energy range 2-60 eV for the n = 3 and 4 shells of Kr, and for the n = 4 and 5 shells of Xe, where interesting non-dipole effects are found. Comparisons of the IPA calculations with correlated relativistic random-phase approximation calculations are made for selected subshells of Ar and Kr, illustrating the influence of correlation on the non-dipole parameters. (C) 1999 Academic Press. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Derevianko, A (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RI Derevianko, Andrei/G-8356-2011 NR 16 TC 90 Z9 91 U1 4 U2 7 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD NOV PY 1999 VL 73 IS 2 BP 153 EP 211 DI 10.1006/adnd.1999.0818 PG 59 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 266XP UT WOS:000084325800001 ER PT J AU Xu, S Gu, J Rhodes, T Belknap, B Rosenbaum, G Offer, G White, H Yu, LC AF Xu, S Gu, J Rhodes, T Belknap, B Rosenbaum, G Offer, G White, H Yu, LC TI The M center dot ADP center dot P-i state is required for helical order in the thick filaments of skeletal muscle SO BIOPHYSICAL JOURNAL LA English DT Article ID RABBIT PSOAS MUSCLE; X-RAY-DIFFRACTION; MYOSIN MOTOR DOMAIN; RELAXED FIBER STIFFNESS; SPIN-LABELED MYOSIN; PARALLEL INHIBITION; STRUCTURAL-CHANGES; FORCE GENERATION; ATP HYDROLYSIS; IONIC-STRENGTH AB The thick filaments of mammalian and avian skeletal muscle fibers are disordered at low temperature, but become increasingly ordered into an helical structure as the temperature is raised. Wray and colleagues (Schlichting, I.,and J. Wray. 1986. J. Muscle Res. Cell Motil. 7:79; Wray, J., R. S. Goody, and K. Holmes. 1986, Adv. Exp. Med. Biol. 226:49-59) interpreted the transition as reflecting a coupling between nucleotide state and global conformation with M . ATP (disordered) being favored at 0 degrees C and M . ADP . P-i (ordered) at 20 degrees C. However, hitherto this has been limited to a qualitative correlation and the biochemical state of the myosin heads required to obtain the helical array has not been unequivocally identified. In the present study we have critically tested whether the helical arrangement of the myosin heads requires the M . ADP . P-i state. X-ray diffraction patterns were recorded from skinned rabbit psoas muscle fiber bundles stretched to non-overlap to avoid complications due to interaction with actin, The effect of temperature on the intensities of the myosin based layer lines and on the phosphate burst of myosin hydrolyzing ATP in solution were examined under closely matched conditions, The results showed that the fraction of myosin mass in the helix closely followed that of the fraction of myosin in the M . ADP . P-i state. Similar results were found by using a series of nucleoside triphosphates, including CTP and GTP, In addition, fibers treated by N-phenylmaleimide (Barnett, V. A., A. Ehrlich, and M, Schoenberg. 1992, Biophys. J 61:358-367) so that the myosin was exclusively in the M ATP state revealed no helical order. Diffraction patterns from muscle fibers in nucleotide-free and in ADP-containing solutions did not show helical structure. All these confirmed that in the presence of nucleotides, the M . NDP . P-i state is required for helical order. We also found that the spacing of the third meridional refection of the thick filament is linked to the helical order. The spacing in the ordered M . NDP . P-i state is 143.4 Angstrom, but in the disordered state, it is 144.2 Angstrom. This may be explained by the different interference functions for the myosin heads and the thick filament backbone. C1 NIAMSD, NIH, Phys Biol Lab, Bethesda, MD 20892 USA. Eastern Virginia Med Sch, Dept Physiol Sci, Norfolk, VA 23501 USA. Argonne Natl Lab, Chicago, IL USA. Univ Bristol, Dept Vet Clin Sci, Bristol, Avon, England. RP Yu, LC (reprint author), NIAMSD, NIH, Phys Biol Lab, Bldg 6,Room 408, Bethesda, MD 20892 USA. NR 71 TC 39 Z9 39 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD NOV PY 1999 VL 77 IS 5 BP 2665 EP 2676 DI 10.1016/S0006-3495(99)77101-8 PG 12 WC Biophysics SC Biophysics GA 253KC UT WOS:000083554900031 PM 10545367 ER PT J AU Selby, PB AF Selby, PB TI Reasons it is doubtful that preconceptional paternal irradiation with plutonium-239 had any effect on cancer induction by methyl-nitroso-urea SO BRITISH JOURNAL OF CANCER LA English DT Letter 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, 1060 Commerce Pk Dr, Oak Ridge, TN 37830 USA. NR 5 TC 0 Z9 0 U1 1 U2 1 PU CHURCHILL LIVINGSTONE PI EDINBURGH PA JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH EH1 3AF, MIDLOTHIAN, SCOTLAND SN 0007-0920 J9 BRIT J CANCER JI Br. J. Cancer PD NOV PY 1999 VL 81 IS 6 BP 1094 EP 1095 DI 10.1038/sj.bjc.6690812 PG 2 WC Oncology SC Oncology GA 252AC UT WOS:000083477700024 PM 10576670 ER PT J AU Leung, LR Hamlet, AF Lettenmaier, DP Kumar, A AF Leung, LR Hamlet, AF Lettenmaier, DP Kumar, A TI Simulations of the ENSO hydroclimate signals in the Pacific Northwest Columbia River basin SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID REGIONAL CLIMATE MODEL; LATERAL BOUNDARY-CONDITIONS; NORTHERN-HEMISPHERE; OROGRAPHIC PRECIPITATION; SPATIAL VARIABILITY; EL-NINO; PREDICTIONS; TEMPERATURE; SKILL; PARAMETERIZATION AB Natural fluctuations in the atmosphere-ocean system related to the El Nino-Southern Oscillation (ENSO) induce climate variability over many parts of the world that is potentially predictable with lead times from seasons to decades. This study examines the potential of using a model nesting approach to provide seasonal climate and streamflow forecasts suitable for water resources management. Two ensembles of perpetual January simulations were performed with a regional climate model driven by a general circulation model (GCM), using observed climatological sea surface temperature (SST) and the mean SST of the warm ENSO years between 1950 and 1994. The climate simulations were then used to drive a macroscale hydrology model to simulate streamflow. The differences between the two ensembles of simulations are defined as the warm ENSO signals. The simulated hydroclimate signals were compared with observations. The analyses focus on the Columbia River basin in the Pacific Northwest. Results show that the global and regional models simulated a warming over the Pacific Northwest that is quite close to the observations. The models also correctly captured the strong wet signal over California and the weak dry signal over the Pacific Northwest during warm ENSO years. The regional climate model consistently performed better than the GCM in simulating the spatial distribution of regional climate and climate signals. When the climate simulations were used to drive a macroscale hydrology model at the Columbia River basin, the simulated streamflow signal resembles that derived from hydrological simulations driven by observed climate. The streamflow simulations were considerably improved when a simple bias correction scheme was applied to the climate simulations. The coupled regional climate and macroscale hydrologic simulations demonstrate the prospect for generating and utilizing seasonal climate forecasts for managing reservoirs. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. NOAA, NCEP, EMC, Climate Modeling Branch, Washington, DC USA. RP Leung, LR (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. RI lettenmaier, dennis/F-8780-2011 OI lettenmaier, dennis/0000-0003-3317-1327 NR 37 TC 56 Z9 58 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD NOV PY 1999 VL 80 IS 11 BP 2313 EP 2329 DI 10.1175/1520-0477(1999)080<2313:SOTEHS>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 253NG UT WOS:000083562200009 ER PT J AU Lal, A Lash, AE Altschul, SF Velculescu, V Zhang, L McLendon, RE Marra, MA Prange, C Morin, PJ Polyak, K Papadopoulos, N Vogelstein, B Kinzler, KW Strausberg, RL Riggins, GJ AF Lal, A Lash, AE Altschul, SF Velculescu, V Zhang, L McLendon, RE Marra, MA Prange, C Morin, PJ Polyak, K Papadopoulos, N Vogelstein, B Kinzler, KW Strausberg, RL Riggins, GJ TI A public database for gene expression in human cancers SO CANCER RESEARCH LA English DT Article ID P53-INDUCED APOPTOSIS; SERIAL ANALYSIS; GLIOBLASTOMA; PROGRESSION; PROFILES; CELLS; TUMOR AB A public database, SAGEmap, was created as a component of the Cancer Genome Anatomy Project to provide a central location for depositing, retrieving, and analyzing human gene expression data. This database uses serial analysis of gene expression to quantify transcript levels in both malignant and normal human tissues. By accessing SAGEmap (http://www.ncbi.nlm.nih.gov/SAGE) the user can compare transcript populations between any of the posted libraries. As an initial demonstration of the database's utility, gene expression in human glioblastomas was compared with that of normal brain white matter. Of the 47,174 unique transcripts expressed in these two tissues, 471 (1.0%) were differentially expressed by more than 5-fold (P < 0.001). Classification of these genes revealed functions consistent with the biological properties of glioblastomas, in particular: angiogenesis, transcription, and cell cycle related genes. C1 Duke Univ, Med Ctr, Dept Pathol, Durham, NC 27710 USA. Natl Lib Med, Natl Ctr Biotechnol Informat, NIH, Bethesda, MD 20894 USA. Johns Hopkins Univ, Sch Med, Johns Hopkins Oncol Ctr, Baltimore, MD 21231 USA. Johns Hopkins Univ, Sch Med, Howard Hughes Med Inst, Baltimore, MD 21231 USA. Johns Hopkins Univ, Sch Med, Dept Pathol, Baltimore, MD 21231 USA. Washington Univ, Genome Sequencing Ctr, St Louis, MO 63108 USA. Univ Calif Lawrence Livermore Natl Lab, IMAGE Consortium, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. NIA, Gerontol Res Ctr, Biol Chem Lab, Baltimore, MD 21224 USA. Dana Farber Canc Inst, Dept Adult Oncol, Boston, MA 02115 USA. Columbia Univ, Dept Pathol, New York, NY 10032 USA. NCI, Off Director, Canc Genome Anat Project, Bethesda, MD 20892 USA. RP Riggins, GJ (reprint author), Duke Univ, Med Ctr, Dept Pathol, Box 3156, Durham, NC 27710 USA. RI Papadopoulos, Nickolas/K-7272-2012; Marra, Marco/B-5987-2008; OI Lash, Alex/0000-0003-3787-1590 NR 20 TC 322 Z9 338 U1 1 U2 6 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD NOV 1 PY 1999 VL 59 IS 21 BP 5403 EP 5407 PG 5 WC Oncology SC Oncology GA 252KG UT WOS:000083500200002 PM 10554005 ER PT J AU Singh, V Panchal, CB Eckhoff, SR AF Singh, V Panchal, CB Eckhoff, SR TI Effect of corn oil on thin stillage evaporators SO CEREAL CHEMISTRY LA English DT Article AB Removal of the germ at the front end of the dry-grind ethanol process using the Quick Germ process reduces the amount of oil in thin stillage. Thin stillage with 4-6% solids is dewatered to 25-30% solids by evaporation. Thin stillage evaporators in a dry-grind ethanol plant foul and have to be periodically taken down for maintenance and cleaning. Fouling caused by thin stillage containing different amounts of oil was studied using an annular fouling probe. It was determined that the rate of fouling in a dry-grind ethanol plant is three times higher when compared with that in a wet-milling ethanol plant. The addition of oil to wet-milled thin stillage significantly affected the rate of fouling. Fouling resistance increased with an increase in oil concentration for wet-milled thin stillage up to a concentration of 1.41%. At a concentration of 1.47%, the rate of fouling decreased. As the concentration of oil increased in dry-grind ethanol thin stillage, the rate of fouling decreased. These results suggest that the Quick Germ process will reduce the rate of heat transfer equipment fouling in a dry-grind ethanol plant, which will decease capital costs and maintenance costs. C1 Univ Illinois, Dept Agr Engn, Urbana, IL 61801 USA. Argonne Natl Lab, Ind Technol Dev Ctr, Argonne, IL 60439 USA. RP Singh, V (reprint author), Univ Illinois, Dept Agr Engn, Urbana, IL 61801 USA. RI Eckhoff, Steven/F-2505-2010 NR 14 TC 12 Z9 12 U1 0 U2 4 PU AMER ASSOC CEREAL CHEMISTS PI ST PAUL PA 3340 PILOT KNOB RD, ST PAUL, MN 55121-2097 USA SN 0009-0352 J9 CEREAL CHEM JI Cereal Chem. PD NOV-DEC PY 1999 VL 76 IS 6 BP 846 EP 849 DI 10.1094/CCHEM.1999.76.6.846 PG 4 WC Chemistry, Applied; Food Science & Technology SC Chemistry; Food Science & Technology GA 257UB UT WOS:000083799300004 ER PT J AU Chang, SL Zhou, CQ AF Chang, SL Zhou, CQ TI Benefits of CFD simulation SO CHEMICAL PROCESSING LA English DT Article AB Computational fluid dynamic (CFD) simulation, a powerful tool for developing advanced energy conversion and combustion systems, can provide the key to designing and operating complex flow systems. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Purdue Univ, Hammond, IN USA. RP Chang, SL (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU PUTMAN PUBL CO PI CHICAGO PA 301 E ERIE STREET, CHICAGO, IL 60611 USA SN 0009-2630 J9 CHEM PROCESS JI Chem. Process. PD NOV PY 1999 VL 62 IS 11 BP 45 EP + PG 5 WC Engineering, Chemical SC Engineering GA 260ZP UT WOS:000083983600009 ER PT J AU Holmes, D Kumaraswamy, S Matzger, AJ Vollhardt, KPC AF Holmes, D Kumaraswamy, S Matzger, AJ Vollhardt, KPC TI On the nature of nonplanarity in the [N]phenylenes SO CHEMISTRY-A EUROPEAN JOURNAL LA English DT Article DE ab initio calculations; acenes; nonplanarity; phenylenes; polycycles; solid-state structures ID DOUBLE-BOND DEFORMATION; CRYSTAL-PACKING; STATISTICAL-ANALYSIS; MOLECULAR-GEOMETRY; AROMATIC SYSTEMS; PHENYLENES; DERIVATIVES; TRIS(BENZOCYCLOBUTADIENO)BENZENE; CYCLOHEXATRIENE; HYDROCARBONS AB The [N]phenylenes display marked deformation from planarity in the crystalline state. In order to probe the generality of this phenomenon, several derivatives were synthesized and their single-crystal X-ray structures were obtained. All new compounds displayed some degree of nonplanarity. Thus, for example, the parent triangular [4]phenylene (4b) has a median bend angle at the ring junction of 1.5 degrees and a range of 0.3 degrees to 3.5 degrees, whereas hexakis[triisopropylsilyl(ethynyl)] triangular [4]phenylene (4c) possesses the bulkiest appendages and the largest median bend angle and range (3.8 degrees and 1.7 degrees-5.6 degrees, respectively). A detailed analysis of the bending and twisting angles at the ring junctions, however, revealed that the magnitude of deformations were independent of topology, molecular size, and substituent type. In contrast to the phenylenes, a Cambridge Structural Database (CSD) search of unsubstituted and non-peri-substituted naphthalenes and anthracenes shows these molecules to be virtually planar in the solid state. A comparison of the single-point energies (HF/6-31G*) of the phenylenes with the acenes calculated for molecules possessing a fixed bend angle at the ring fusion of 3 degrees, 6 degrees, 9 degrees, and 12 degrees reveals the former to be 26% to 45% easier to deform than the latter. Based on these results, the nonplanarity seen for the phenylenes is most likely a consequence of crystal-packing forces deforming particularly flexible molecules. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Vollhardt, KPC (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Matzger, Adam/G-7497-2016 OI Matzger, Adam/0000-0002-4926-2752 NR 85 TC 313 Z9 315 U1 4 U2 45 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0947-6539 J9 CHEM-EUR J JI Chem.-Eur. J. PD NOV PY 1999 VL 5 IS 11 BP 3399 EP 3412 DI 10.1002/(SICI)1521-3765(19991105)5:11<3399::AID-CHEM3399>3.0.CO;2-V PG 14 WC Chemistry, Multidisciplinary SC Chemistry GA 254XV UT WOS:000083640300033 ER EF