FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Tuck, DM AF Tuck, DM TI "DNAPL migration through a fractured perching layer" by Daniel B. Stephens, James A. Kelsey, Mark A. Prieksat, Mel G. Piepho, Chao Shan, and Mark D. Ankeny, July-August 1998 issue, v. 36, no. 4 : 605-610. Discussion SO GROUND WATER LA English DT Editorial Material ID NONAQUEOUS PHASE LIQUIDS; POROUS-MEDIA; FIELD EXPERIMENT; TETRACHLOROETHYLENE; BEHAVIOR C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Tuck, DM (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Bldg 773-42A, Aiken, SC 29808 USA. NR 18 TC 2 Z9 2 U1 0 U2 0 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD JUL-AUG PY 1999 VL 37 IS 4 BP 485 EP 486 DI 10.1111/j.1745-6584.1999.tb01129.x PG 2 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 213JK UT WOS:000081268800004 ER PT J AU Hinds, JJ Ge, SM Fridrich, CJ AF Hinds, JJ Ge, SM Fridrich, CJ TI Numerical modeling of perched water under Yucca Mountain, Nevada SO GROUND WATER LA English DT Article ID CAPILLARY BARRIERS; TUFF AB The presence of perched water near the potential high-level nuclear waste repository area at Yucca Mountain, Nevada, has important implications for waste isolation. Perched water occurs because of sharp contrasts in rock properties, in particular between the strongly fractured repository host rock (the Topopah Spring welded tuff) and the immediately underlying vitrophyric (glassy) subunit, in which fractures are sealed by clays that were formed by alteration of the volcanic glass. The vitrophyre acts as a vertical barrier to unsaturated flow throughout much of the potential repository area. Geochemical analyses (Yang et al, 1996) indicate that perched water is relatively young, perhaps younger than 10,000 years. Given the low permeability of the rock matric, fractures and perhaps fault zones must play a crucial role in unsaturated flow. The geologic setting of the major perched water bodies under Yucca Mountain suggests that faults commonly form barriers to lateral flow at the level of the repository horizon, but may also form important pathways for vertical infiltration from the repository horizon down to the water table, Using the numerical code UNSAT2, two factors believed to influence the perched water system at Yucca Mountain, climate and fault-zone permeability; are explored. The two-dimensional model predicts that the volume of water held within the perched water system may greatly increase under wetter climatic conditions, and that perched water bodies may drain to the water table along fault zones. Modeling results also show fault flow to be significantly attenuated in the Paintbrush Tuff non-welded hydrogeologic unit. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. US Geol Survey, Denver, CO 80225 USA. RP Hinds, JJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS-90-1116, Berkeley, CA 94720 USA. NR 32 TC 6 Z9 6 U1 0 U2 6 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD JUL-AUG PY 1999 VL 37 IS 4 BP 498 EP 504 DI 10.1111/j.1745-6584.1999.tb01135.x PG 7 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 213JK UT WOS:000081268800009 ER PT J AU Musolino, SV AF Musolino, SV TI Andrew P. Hull - 1920-1999 - In memoriam SO HEALTH PHYSICS LA English DT Biographical-Item C1 Brookhaven Natl Lab, Upton, NY 11973 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD JUL PY 1999 VL 77 IS 1 BP 105 EP 107 DI 10.1097/00004032-199907000-00017 PG 3 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 205TN UT WOS:000080836800016 ER PT J AU Xiao, GH Lim, JH Yang, S Stryland, EV Bass, M Weichman, L AF Xiao, GH Lim, JH Yang, S Stryland, EV Bass, M Weichman, L TI Z-scan measurement of the ground and excited state absorption cross sections of Cr4+ in yttrium aluminum garnet SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE nonlinear optics; optical materials; optical saturation ID Q-SWITCHED LASERS; SATURABLE-ABSORBER; OPTIMIZATION; MODEL AB Z-scan measurements of the ground and excited state absorption cross sections of Cr4+-doped yttrium aluminum garnet are reported. These quantities are found to depend on crystal preparation but are independent of temperature from -60 degrees C to 98 degrees C. Their ratio is shown to weakly determine the energy output of a passively Q-switched Nd:glass laser using this material as the saturable absorber. C1 Univ Cent Florida, CREOL, Sch Opt, Orlando, FL 32801 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Xiao, GH (reprint author), Univ Cent Florida, CREOL, Sch Opt, Orlando, FL 32801 USA. NR 17 TC 52 Z9 53 U1 0 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JUL PY 1999 VL 35 IS 7 BP 1086 EP 1091 DI 10.1109/3.772180 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 211NK UT WOS:000081167000013 ER PT J AU Torres, JH Nelson, JS Tanenbaum, BS Milner, TE Goodman, DM Anvari, B AF Torres, JH Nelson, JS Tanenbaum, BS Milner, TE Goodman, DM Anvari, B TI Estimation of internal skin temperatures in response to cryogen spray cooling: Implications for laser therapy of port wine stains SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE cutaneous hypervascular lesions; dermatology; refrigerant; selective thermal injury; skin model ID PULSED PHOTOTHERMAL RADIOMETRY; BLOOD-VESSELS; DYE-LASER; BIOLOGICAL TISSUES; THERMAL RELAXATION; DURATION; CHROMOPHORES; TOXICOLOGY AB In many port wine stain (PWS) patients, successful clearing is not achieved even after multiple laser treatments because of inadequate heat generation within the targeted blood vessels. Use of higher radiant exposures has been suggested to improve lesion clearing, but risk of epidermal injury due to nonspecific absorption by melanin increases. It has been demonstrated that cryogen spray cooling (CSC) can protect the epidermis from nonspecific thermal injury during laser treatment of PWS, Inasmuch as epidermal melanin concentration and blood vessel depth vary among patients, evaluation of internal skin temperatures in response to CSC is essential for further development and optimization of treatment parameters on an individual patient basis, We present internal temperature measurements in an epoxy resin phantom in response to CSC and use the results in conjunction with a mathematical model to predict the temperature distribution within human skin for various cooling parameters, Measurements on the epoxy resin phantom show that cryogen film temperature is well below the cryogen boiling point, but a poor thermal contact exists at the cryogen-phantom interface. Based on phantom measurements and model predictions, internal skin temperature reduction remains confined to the upper 400 mu m for spurt durations as long as 200 ms. At the end of a 100 ms spurt, our results show a 31 degrees C temperature reduction at the surface, 12 degrees C at a depth of 100 mu m, and 4 degrees C at a depth of 200 mu m in human skin. Analysis of estimated temperature distributions in response to CSC and temperature profiles obtained by pulsed photothermal radiometry indicates that a significant protective effect is achieved at the surface of laser irradiated PWS skin. Protection of the epidermal basal layer, however, poses a greater challenge when high radiant exposures are used. C1 Rice Univ, Dept Bioengn, Houston, TX 77005 USA. Univ Calif Irvine, Beckman Laser Inst & Med Clin, Irvine, CA 92612 USA. Harvey Mudd Coll, Dept Engn, Claremont, CA 91711 USA. Univ Texas, Dept Elect & Comp Engn, Austin, TX 78712 USA. Univ Texas, Biomed Engn Program, Austin, TX 78712 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Torres, JH (reprint author), Rice Univ, Dept Bioengn, Houston, TX 77005 USA. NR 31 TC 56 Z9 56 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD JUL-AUG PY 1999 VL 5 IS 4 BP 1058 EP 1066 DI 10.1109/2944.796330 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 248CM UT WOS:000083257800026 ER PT J AU Telenkov, SA Tanenbaum, BS Goodman, DM Nelson, JS Milner, TE AF Telenkov, SA Tanenbaum, BS Goodman, DM Nelson, JS Milner, TE TI In vivo infrared tomographic imaging of laser-heated blood vessels SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE focal plane array; imaging; infrared; port wine stain; tomography ID PULSED PHOTOTHERMAL RADIOMETRY; LIGHT; SKIN AB We demonstrate a method for infrared tomographic imaging of the initial three-dimensional (3-D) temperature increase of in vivo blood vessels following pulsed laser exposure. Using a time-sequence of infrared images recorded by a fast focal plane array camera as input data, a reconstruction algorithm is used to compute the initial 3-D temperature increases in the chick chorioallantoic membrane and port wine stain in human skin. The noncontact tomographic imaging method is relevant to various laser therapies that rely on a photothermal mechanism for selective modification of tissue and mag find diagnostic application to determine optimal laser dosimetry, position, and size of targeted subsurface chromophores. C1 Univ Texas, Biomed Engn Program, Austin, TX 78712 USA. Harvey Mudd Coll, Dept Engn, Claremont, CA 91711 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Irvine, Beckman Laser Inst & Med Clin, Irvine, CA 92612 USA. RP Telenkov, SA (reprint author), Univ Texas, Biomed Engn Program, Austin, TX 78712 USA. NR 21 TC 27 Z9 27 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD JUL-AUG PY 1999 VL 5 IS 4 BP 1193 EP 1199 DI 10.1109/2944.796346 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 248CM UT WOS:000083257800042 ER PT J AU Muljadi, E Butterfield, CP Wan, YH AF Muljadi, E Butterfield, CP Wan, YH TI Axial-flux modular permanent-magnet generator with a toroidal winding for wind-turbine applications SO IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS LA English DT Article; Proceedings Paper CT 1998 Industry-Applications-Society Annual Meeting CY OCT 12-16, 1998 CL ST LOUIS, MISSOURI SP Ind Applicat Soc DE axial flux; modular generator; permanent magnet; wind energy AB Permanent-magnet (PM) generators have been used for wind turbines for many years. Many small wind-turbine manufacturers use direct-drive PM generators. For wind-turbine generators, the design philosophy must cover the following characteristics: low cost, light weight, low speed, high torque, and variable-speed generation. The generator is easy to manufacture and the design can be scaled up for a larger size without major retooling, A modular PM generator with axial flux direction was chosen. The permanent magnet used is NdFeB or ferrite magnet with flux guide to focus flux density in the air gap. Each unit module of the generator may consist of one, two, or more phases, Each generator can be expanded to two or more unit modules. Each unit module is built from simple modular poles. The stator winding is formed like a torus, Thus, the assembly process is simplified and the winding insertion in the slot is less tedious. We built a prototype of one unit module and performed preliminary tests in our laboratory, Follow-up tests will be conducted in our laboratory to improve the design. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Muljadi, E (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 7 TC 62 Z9 63 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-9994 J9 IEEE T IND APPL JI IEEE Trans. Ind. Appl. PD JUL-AUG PY 1999 VL 35 IS 4 BP 831 EP 836 DI 10.1109/28.777191 PG 6 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA 221XT UT WOS:000081753400013 ER PT J AU Brubaker, MA Lindgren, SR Frimpong, GK Walden, JM AF Brubaker, MA Lindgren, SR Frimpong, GK Walden, JM TI Streaming electrification measurements in a 1/4-scale transformer model SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE transformers; static electrification; lower plenum; high-low space; pump operation; streaming currents; charge distribution ID INSULATION AB Streaming electrification occurs in large power transformers when charge separation takes place at the oil/cellulose interface as the oil is circulated for cooling and can cause catastrophic failures. This study was performed with practical emphasis to examine the impact of cooling loop orientation and operation in the transformer lower plenum upon the electrification phenomenon. A simplified 1/4-scale shell-form transformer insulation structure was designed and fabricated for testing in an appropriately scaled tank complete with six individual cooling loops. Discrete electrodes along the oil flow path facilitated mapping of the internal streaming current distributions as a function of various operating conditions. The streaming current magnitudes and spatial distributions were found to vary with pump configuration, temperature and moisture. Furthermore, certain pumping arrangements which provided interfering transverse flows were shown to reduce local streaming electrification. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Elect Power Res Inst, Palo Alto, CA 94304 USA. ABB Elect Syst Technol Inst, Raleigh, NC 27606 USA. RP Brubaker, MA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 11 TC 6 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD JUL PY 1999 VL 14 IS 3 BP 978 EP 985 DI 10.1109/61.772343 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 209KY UT WOS:000081047900046 ER PT J AU Seinost, G Dykhuizen, DE Dattwyler, RJ Golde, WT Dunn, JJ Wang, IN Wormser, GP Schriefer, ME Luft, BJ AF Seinost, G Dykhuizen, DE Dattwyler, RJ Golde, WT Dunn, JJ Wang, IN Wormser, GP Schriefer, ME Luft, BJ TI Four clones of Borrelia burgdorferi sensu stricto cause invasive infection in humans SO INFECTION AND IMMUNITY LA English DT Article ID OUTER-SURFACE PROTEIN; EARLY LYME-DISEASE; FRAGMENT-LENGTH-POLYMORPHISM; OSPC GENE; C OSPC; GARINII; VACCINE; SERODIAGNOSIS; RECOMBINATION; CULTIVATION AB Lyme disease begins at the site of a tick bite, producing a primary infection with spread of the organism to secondary sites occurring early in the course of infection. A major outer surface protein expressed by the spirochete early in infection is outer surface protein C (OspC). In Borrelia burgdorferi sensu stricto, OspC is highly variable. Based on sequence divergence, alleles of ospC can be divided into 21 major groups. To assess whether strain differences defined by ospC group are linked to invasiveness and pathogenicity, we compared the frequency distributions of major ospC groups from ticks, from the primary erythema migrans skin lesion, and from secondary sites, principally from blood and spinal fluid. The frequency distribution of ospC groups from ticks is significantly different from that from primary sites, which in turn is significantly different from that from secondary sites. The major groups A, B, I, and K had higher frequencies in the primary sites than in ticks and were the only groups found in secondary sites. We define three categories of major ospC groups: one that is common in ticks but very rarely if ever causes human disease, a second that causes only local infection at the tick bite site, and a third that causes systemic disease. The finding that all systemic B. burgdorferi sensu stricto infections are associated with four ospC groups has importance in the diagnosis, treatment, and prevention of Lyme disease. C1 SUNY Stony Brook, Dept Med, Div Clin Immunol Allergy, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Med, Dept Ecol & Evolut, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. New York Med Coll, Dept Med, Valhalla, NY 10595 USA. Ctr Dis Control, Ft Collins, CO 80522 USA. RP Dattwyler, RJ (reprint author), SUNY Stony Brook, Dept Med, Div Clin Immunol Allergy, Stony Brook, NY 11794 USA. OI Dattwyler, Raymond/0000-0002-1983-1301; Luft, Benjamin/0000-0001-9008-7004 NR 43 TC 190 Z9 193 U1 1 U2 8 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0019-9567 J9 INFECT IMMUN JI Infect. Immun. PD JUL PY 1999 VL 67 IS 7 BP 3518 EP 3524 PG 7 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA 209RZ UT WOS:000081063800047 PM 10377134 ER PT J AU Allen, HW Abate, ML AF Allen, HW Abate, ML TI Work process analysis: a necessary step in the development of decision support systems. An aviation safety case study SO INTERACTING WITH COMPUTERS LA English DT Article DE work process analysis; decision support systems; aviation safety; human computer interface design; task analysis; system design AB This paper demonstrates the importance of work process modeling and supporting data analysis in system development. To illustrate the process of modeling for system development, we describe how traditional task analysis was used in our effort to understand the work processes associated with the Federal Aviation Administration's (FAA's) airworthiness and operations surveillance inspection activities. Further, the integration of risk assessment techniques resulted in a validated task analysis providing a review of the as-is state of surveillance activities. It is also shown how the as-is surveillance work processes that resulted from these studies were used as the foundation for a re-engineered (re-eng) surveillance work process model. We conclude by describing a follow-on activity, the development of a safety critical work process model, which reflects an integration of the as-is and re-engineered work process descriptions, the human factors literature, inspection data analysis, federal aviation regulations and identified areas of safety criticality. (C) 1999 Published by Elsevier Science B.V. C1 Sandia Natl Labs, Stat & Human Factors Dept, Albuquerque, NM 87185 USA. RP Abate, ML (reprint author), Sandia Natl Labs, Stat & Human Factors Dept, POB 5800, Albuquerque, NM 87185 USA. NR 7 TC 2 Z9 3 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0953-5438 J9 INTERACT COMPUT JI Interact. Comput. PD JUL PY 1999 VL 11 IS 6 SI SI BP 623 EP 643 DI 10.1016/S0953-5438(98)00047-2 PG 21 WC Computer Science, Cybernetics; Ergonomics SC Computer Science; Engineering GA 218RA UT WOS:000081564400003 ER PT J AU Wang, JG Hsiung, LM Nieh, TG AF Wang, JG Hsiung, LM Nieh, TG TI Microstructural instability in a crept fully lamellar TiAl alloy SO INTERMETALLICS LA English DT Article DE titanium aluminides, based on TiAl; creep; thermal stability; twinning; microstructure ID ROOM-TEMPERATURE; STOICHIOMETRIC COMPOSITION; TITANIUM ALUMINIDES; CREEP DEFORMATION; ALPHA(2) PLATES; TI-48AL-2MN-2NB; SPHEROIDIZATION; CRYSTALS; BEHAVIOR; TWINS AB A fully-lamellar TiAl alloy creep deformed at 760 degrees C with a stress of 138 MPa and a strain of similar to 1.5% was employed in the examination of microstructural instability. Fragmentation and spheroidization of alpha(2) lamellae and formation of recrystallized gamma grains (gamma(G)) inside the lamellar colony were observed. It was proposed that the fragmentation and spheroidization of alpha(2) lamellae during creep could be caused by either a subgrain boundary groove mechanism or an intersection of deformation twins with alpha(2) phase lamellae. Possible mechanisms were proposed. The formation of coarsened gamma(G) grains was frequently observed. The gamma(G) grains had crystallographic relationships with the lamellar structure as < (1) over bar 10 >(gamma G)//<(1) over bar 10 gamma>//[11 (2) over bar 0](alpha 2) and {111}gamma(G)perpendicular to{111}gamma//(0001)(alpha 2). Simple thermodynamical analysis was done on the formation of gamma(G) grains. Deformation and dynamically recrystallized structures in the gamma(G) grains were also observed. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Wang, JG (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-370,POB 808, Livermore, CA 94551 USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 34 TC 39 Z9 39 U1 0 U2 6 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD JUL PY 1999 VL 7 IS 7 BP 757 EP 763 DI 10.1016/S0966-9795(98)00125-3 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 201TE UT WOS:000080611000002 ER PT J AU Hsiung, LM Nieh, TG AF Hsiung, LM Nieh, TG TI Creep deformation of fully lamellar TiAl controlled by the viscous glide of interfacial dislocations SO INTERMETALLICS LA English DT Article DE titanium aluminides, based on TiAl; creep (properties and mechanisms); defects : dislocation geometry and arrangement ID MECHANICAL-PROPERTIES; ALLOY AB Creep mechanisms of fully lamellar TiAl with a refined microstructure (gamma lamellae: 100-300 nm thick, alpha(2) lamellae: 10-50 nm thick) have been investigated. A nearly linear creep behavior (i.e. the steady-state creep rate is nearly proportional to the applied stress) was observed when the alloy was creep deformed at low applied stresses (< 400 MPa) and intermediate temperatures (650-810 degrees C). Since the operation and multiplication of lattice dislocations within both gamma and alpha(2) lamellae are very limited in a low stress level as a result of the refined lamellar microstructure, creep mechanisms based upon glide and/or climb of lattice dislocations become insignificant. Instead, the motion of interfacial dislocation arrays on gamma/alpha(2) and gamma/gamma interfaces (i.e. interface sliding) has found to be a predominant deformation mechanism. According to the observed interfacial substructure caused by interface sliding and the measured activation energy for creep, it is proposed that creep deformation of the refined lamellar TiAl in the intermediate-temperature and low-stress regime is primarily controlled by the viscous glide of interfacial dislocations. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Div Mat Sci & Technol, Livermore, CA 94551 USA. RP Hsiung, LM (reprint author), Lawrence Livermore Natl Lab, Div Mat Sci & Technol, L-370,POB 808, Livermore, CA 94551 USA. EM hsiang1@llnl.gov RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 23 TC 29 Z9 29 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 EI 1879-0216 J9 INTERMETALLICS JI Intermetallics PD JUL PY 1999 VL 7 IS 7 BP 821 EP 827 DI 10.1016/S0966-9795(98)00135-6 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 201TE UT WOS:000080611000008 ER PT J AU Woods, JL Daniewicz, SR Nellums, R AF Woods, JL Daniewicz, SR Nellums, R TI Increasing the bending fatigue strength of carburized spur gear teeth by presetting SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article DE fatigue; finite element analysis; residual stress; spur gear AB Presetting is used to enhance the fatigue strength of many products. This study investigated the use of presetting as a method to increase the bending fatigue strength of carburized spur gear teeth. An elastic-perfectly plastic finite element model was formulated to predict the effects of presetting on a gear tooth. The model's results were verified both analytically and experimentally. It was determined that presetting induces compressive residual stress in the area of the tooth from which fatigue cracks typically originate. Fatigue tests and subsequent statistical analyses were conducted at three load levels with R = 0.10 to determine the effect of presetting on fatigue life. Both the finite element model and fatigue tests showed presetting as more effective than carburization in inducing compressive residual stress and thereby increasing fatigue strength. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Mississippi State Univ, Dept Mech Engn, Mississippi State, MS 39762 USA. Pacific NW Lab, Richland, WA 99352 USA. Eaton Corp, Southfield, MI 48037 USA. RP Daniewicz, SR (reprint author), Mississippi State Univ, Dept Mech Engn, POB ME, Mississippi State, MS 39762 USA. NR 22 TC 13 Z9 14 U1 1 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PD JUL PY 1999 VL 21 IS 6 BP 549 EP 556 DI 10.1016/S0142-1123(99)00011-0 PG 8 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 202AD UT WOS:000080629200003 ER PT J AU Simon, PM Esser, J Nagel, K AF Simon, PM Esser, J Nagel, K TI Simple queueing model applied to the city of Portland SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article DE large scale transportation simulations; traffic simulations; transportation planning; queueing models ID MICROSIMULATION AB We use a simple traffic micro-simulation model based on queueing dynamics as introduced by Gawron [IJMPC, 9(3):393, 1998] in order to simulate traffic in Portland/Oregon. Links have a flow capacity, that is, they do not release more vehicles per second than is possible according to their capacity. This leads to queue built-up if demand exceeds capacity. Links also have a storage capacity, which means that once a link is full, vehicles that want to enter the link need to wait. This leads to queue spill-back through the network. The model is compatible with route-plan-based approaches such as TRANSIMS, where each vehicle attempts to follow its pre-computed path. Yet, both the data requirements and the computational requirements are considerably lower than for the full TRANSIMS microsimulation. Indeed, the model uses standard emme/2 network data, and runs about eight times faster than real time with more than 100 000 vehicles simultaneously in the simulation on a single Pentium-type CPU. We derive the model's fundamental diagrams and explain. it. The simulation is used to simulate traffic on the emme/2 network of the Portland (Oregon) metropolitan region (20 000 links). Demand is generated by a simplified home-to-work destination assignment which generates about half a million trips for the morning peak. Route assignment is done by iterative feedback between micro-simulation and router. An iterative solution of the route assignment for the above problem can be achieved within about half a day of computing time on a desktop workstation. We compare results with field data and with results of traditional assignment runs by the Portland Metropolitan Planning Organization. Thus, with a model such as this one, it is possible to use a dynamic, activities-based approach to transportation simulation (such as in TRANSIMS) with affordable data and hardware. This should enable systematic research about the coupling of demand generation, route assignment, and micro-simulation output. C1 Univ Calif Los Alamos Natl Lab, Santa Fe Inst, Santa Fe, NM 87501 USA. RP Simon, PM (reprint author), Univ Calif Los Alamos Natl Lab, Santa Fe Inst, 1399 Hyde Pk Rd, Santa Fe, NM 87501 USA. NR 31 TC 18 Z9 18 U1 3 U2 5 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD JUL PY 1999 VL 10 IS 5 BP 941 EP 960 DI 10.1142/S0129183199000747 PG 20 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 260EZ UT WOS:000083937700015 ER PT J AU Mosher, JC AF Mosher, JC TI Efficiently solving the EEG/MEG forward model SO INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87544 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8760 J9 INT J PSYCHOPHYSIOL JI Int. J. Psychophysiol. PD JUL PY 1999 VL 33 IS 1 MA 14 BP 39 EP 39 PG 1 WC Psychology, Biological; Neurosciences; Physiology; Psychology; Psychology, Experimental SC Psychology; Neurosciences & Neurology; Physiology GA 223AF UT WOS:000081817000021 ER PT J AU Mosher, JC AF Mosher, JC TI Solutions to EEG/MEG inverse models SO INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87544 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8760 J9 INT J PSYCHOPHYSIOL JI Int. J. Psychophysiol. PD JUL PY 1999 VL 33 IS 1 MA 15 BP 39 EP 39 PG 1 WC Psychology, Biological; Neurosciences; Physiology; Psychology; Psychology, Experimental SC Psychology; Neurosciences & Neurology; Physiology GA 223AF UT WOS:000081817000022 ER PT J AU Wood, CC AF Wood, CC TI Volume models and source models for the electromagnetic inverse problem SO INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8760 J9 INT J PSYCHOPHYSIOL JI Int. J. Psychophysiol. PD JUL PY 1999 VL 33 IS 1 MA 13 BP 39 EP 39 PG 1 WC Psychology, Biological; Neurosciences; Physiology; Psychology; Psychology, Experimental SC Psychology; Neurosciences & Neurology; Physiology GA 223AF UT WOS:000081817000020 ER PT J AU Lucas, JN Deng, W Moore, D Hill, F Wade, M Lewis, A Sailes, F Kramer, C Hsieh, A Galvan, N AF Lucas, JN Deng, W Moore, D Hill, F Wade, M Lewis, A Sailes, F Kramer, C Hsieh, A Galvan, N TI Background ionizing radiation plays a minor role in the production of chromosome translocations in a control population SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID SISTER-CHROMATID EXCHANGES; IN-SITU HYBRIDIZATION; BIOLOGICAL DOSIMETRY; HUMAN-LYMPHOCYTES; DOSE RECONSTRUCTION; BODY IRRADIATION; EXPOSURE; ABERRATIONS; FREQUENCY; AGE AB Purpose: To obtain a relationship between background chromosome translocation frequency and age with translocation frequency measured to a high statistical precision, and to identify the role of background ionizing radiation in the production of chromosome translocations in a control population. Materials and methods: Lymphocytes from 35 healthy control individuals (15 females and 20 males) were scored, using fluorescence in situ hybridization, for the presence of chromosomal translocations. Translocation frequencies were measured to a high statistical precision (s.d. 25% or less for each individual). These control subjects were of varying ages, ranging from 0 (cord blood) to 98 years. Results: In a total of 521,492 metaphases (203,754 genome equivalent cells) scored, an average of 5,822 genome equivalent cells per individual, 764 translocations were observed in the 35 individuals. The translocation frequencies ranged from 0 (for cord blood) to 0.0167 (for a 98 year old) translocations per cell. The average age and translocation frequency was 50 years and 0.004 translocations per cell, respectively. The best fit of the relationship between translocations and age was: Y = 7 x 10(-4) + 6.9 x 10(-6) A + 1.35 x 10(-6) A(2), which does not obey the linear relationship expected from chronic background radiation alone. The curvilinear relationship observed clearly shows that other endogenous and exogenous clastogens or clastogenic events, in addition to radiation, serve to generate chromosome translocations in control populations. Conclusion: The background translocation frequency in control individuals follows a curvilinear relationship with age. No significant variation was observed between individuals of the same age. Clastogenic processes of normal aging and physiological factors in additional to ionizing radiation play a major role in the production of chromosome translocations in a control population. Background radiation, however, appears to play a minor role in chromosome translocation production in control individuals living near sea level. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Sichuan Inst Radiat Hlth & Protect, Sichuan Inst Occupat Hlth, Chengdu 610041, Peoples R China. RP Lucas, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 28 TC 40 Z9 41 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD JUL PY 1999 VL 75 IS 7 BP 819 EP 827 PG 9 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 218RF UT WOS:000081564900004 PM 10489893 ER PT J AU Williams, TO AF Williams, TO TI A generalized multilength scale nonlinear composite plate theory with delamination SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article DE laminated plates; multilength scale plate theory; HSDT; delamination; interfacial constitutive relations; buckling; geometric nonlinearity ID HIGH-ORDER THEORY; LAMINATED PLATES; MODEL; DEFORMATION; INTERFACE; STRESSES AB A new type of plate theory for the nonlinear analysis of laminated plates in the presence of delaminations and other history-dependent effects is presented. The formulation is based on a generalized two length scale displacement field obtained from a superposition of global and local displacement effects. The functional forms of global and local displacement fields are arbitrary. The theoretical framework introduces a unique coupling between the length scales and represents a novel two length scale or local-global approach to plate analysis. Appropriate specialization of the displacement field can be used to reduce the theory to any currently available, variationally derived, displacement based (discrete layer, 'smeared', or 'zig-zag') plate theory. The theory incorporates delamination and/or nonlinear elastic or inelastic interfacial behavior in a unified fashion through the use of interfacial constitutive (cohesive) relations. Arbitrary interfacial constitutive relations can be incorporated into the theory without the need for reformulation of the governing equations. The theory is sufficiently general that any material constitutive model can be implemented within the theoretical framework. The theory accounts for geometric nonlinearities to allow for the analysis of buckling behavior. The theory represents a comprehensive framework for developing any order and type of displacement based plate theory in the presence of delamination, buckling, and/or nonlinear material behavior as well as the interactions between these effects. The linear form of the theory is validated by comparison with exact solutions for the behavior of perfectly bonded and delaminated laminates in cylindrical bending. The theory shows excellent correlation with the exact solutions for both the inplane and out-of-plane effects and the displacement jumps due to delamination. The theory can accurately predict the through-the-thickness distributions of the transverse stresses without the need to integrate the pointwise equilibrium equations. The use of a low order of the general theory, i.e. use of both global and local displacement fields, reduces the computational expense compared to a purely discrete layer approach to the analysis of laminated plates without loss of accuracy. The increased efficiency, compared to a solely discrete layer theory, is due to the coupling introduced in the theory between the global and local displacement fields. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Williams, TO (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-3, Los Alamos, NM 87545 USA. NR 32 TC 28 Z9 28 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD JUL PY 1999 VL 36 IS 20 BP 3015 EP 3050 DI 10.1016/S0020-7683(98)00138-3 PG 36 WC Mechanics SC Mechanics GA 173ZY UT WOS:000079010700004 ER PT J AU Song, B Haggblom, MM Zhou, JZ Tiedje, JM Palleroni, NJ AF Song, B Haggblom, MM Zhou, JZ Tiedje, JM Palleroni, NJ TI Taxonomic characterization of denitrifying bacteria that degrade aromatic compounds and description of Azoarcus toluvorans sp nov and Azoarcus toluclasticus sp nov. SO INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY LA English DT Article DE Azoarcus toluvorans sp nov.; Azoarcus toluclasticus sp nov.; aromatic degradation; taxonomy ID ANAEROBIC DEGRADATION; TRICHLOROETHENE COMETABOLISM; THAUERA-AROMATICA; TOLULYTICUS TOL-4; SEQUENCE-ANALYSIS; TOLUENE; PHENOL; PROTEOBACTERIA; IDENTIFICATION; METABOLISM AB A taxonomic characterization of twenty-one strains capable of degrading aromatic compounds under denitrifying conditions, isolated from ten different geographical locations, was performed on the basis of general morphological and physiological characteristics, cellular fatty acids, DNA base composition, small ribosomal (16S) subunit DNA sequences, whole-cell protein patterns and genomic DNA fragmentation analysis, in addition to DNA similarity estimations using hybridization methods. The collection of strains was subdivided into a number of different groups. A first group, consisting of four strains, could be assigned to the previously described species Azoarcus tolulyticus. A second group (five strains) had DNA which reannealed highly to that of strains of the first group, and it is considered to represent a genomovar of A. tolulyticus. The third and fourth groups, composed of a total of five strains, represent a new species of Azoarcus, Azoarcus toluclasticus (group 3) and a genomovar of this species (group 4), respectively, Finally, the fifth group, with two strains, corresponds to another new species of the genus Azoarcus. Azoarcus toluvorans. In addition to these five groups, the collection includes five individual strains perhaps representing as many different new species. The above classification is partially consistent with the results of approaches other than DNA-DNA hybridization (electrophoretic patterns of whole-cell proteins and of the fragments obtained after digestion of total DNA with infrequently cutting restriction enzymes). On the other hand, no correlation of these groupings was found in terms of the cellular fatty acid composition. It is also unfortunate that no simple sets of easily determinable phenotypic properties could be defined as being characteristic of each of the groups. C1 Rutgers State Univ, Cook Coll, Biotechnol Ctr Agr & Environm, New Brunswick, NJ 08901 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. RP Palleroni, NJ (reprint author), Rutgers State Univ, Cook Coll, Biotechnol Ctr Agr & Environm, New Brunswick, NJ 08901 USA. RI Haggblom, Max/E-7597-2010 OI Haggblom, Max/0000-0001-6307-7863 FU NIEHS NIH HHS [ES-04911] NR 41 TC 58 Z9 59 U1 1 U2 6 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING, BERKS, ENGLAND RG7 1AE SN 0020-7713 J9 INT J SYST BACTERIOL JI Int. J. Syst. Bacteriol. PD JUL PY 1999 VL 49 BP 1129 EP 1140 PN 3 PG 12 WC Microbiology SC Microbiology GA 216ND UT WOS:000081448000023 PM 10425771 ER PT J AU Taatjes, CA AF Taatjes, CA TI Time-resolved infrared absorption measurements of product formation in Cl atom reactions with alkenes and alkynes SO INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY LA English DT Review ID FREQUENCY-MODULATION SPECTROSCOPY; DIFFERENTIAL CROSS-SECTIONS; GAS-PHASE REACTIONS; UNIMOLECULAR ELIMINATION-REACTIONS; TRANSITION-STATE REGION; LASER FLASH-PHOTOLYSIS; CHLORINE ATOMS; PRESSURE-DEPENDENCE; RATE COEFFICIENTS; RATE CONSTANTS AB The reactions of Cl with hydrocarbons have been the subjects of study since the early days of experimental chemical kinetics. The reactions of Cl atoms with alkanes are prototypical atom abstractions;the reactions with alkenes and alkynes display a richer chemistry because of the possibility of addition to form a chlorinated hydrocarbon radical. This review discusses recent infrared absorption investigations of the reactions of Cl with unsaturated hydrocarbons, with an emphasis on deconvolution of the addition and metathesis (i.e. abstraction or addition-elimination) pathways. These experiments are described in relation to other Cl + hydrocarbon reactions, and several examples illustrate the sensitivity of the kinetic and mechanistic behaviour of the Cl + alkene reactions to the thermochemistry of the individual systems. In the Cl + C(2)H(4) reaction, where metathesis is endothermic, addition dominates except at elevated temperatures or low pressures, but the exothermic metatheses of Cl with C(3) unsaturated species effectively compete with addition even at room temperature. An example of thermochemical differences creating qualitatively different kinetic behaviours is given by the reactions of Cl with the C(3)H(4) isomers allene (CH(2)=C=CH(2)) and propyne (CH=C-CH(3)). Whereas Cl+propyne displays kinetics similar to other Cl + alkene systems, the Cl + aliene reaction shows unusual behaviour driven by the formation of the resonance-stabilized chloroallyl radical. Characterization of the nature of abstraction in Cl + alkene systems and examination of the role of addition-elimination in exothermic reactions are suggested as important areas for further investigation. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Taatjes, CA (reprint author), Sandia Natl Labs, Combust Res Facil, Mail Stop 9055, Livermore, CA 94551 USA. NR 143 TC 28 Z9 28 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0144-235X J9 INT REV PHYS CHEM JI Int. Rev. Phys. Chem. PD JUL-SEP PY 1999 VL 18 IS 3 BP 419 EP 458 DI 10.1080/014423599229938 PG 40 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 246PL UT WOS:000083172600003 ER PT J AU Yagi, Y Serianni, G Ji, H Maejima, Y AF Yagi, Y Serianni, G Ji, H Maejima, Y TI Correlation studies on fast electrons and dynamo-related activities in a reversed-field pinch plasma SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS LA English DT Article DE reversed-field pinch; fast electron; dynamo electric field; electron energy analyzer; correlation; TPE-1RM20 ID MAGNETIC-FIELD; EDGE; FLUCTUATIONS; TRANSPORT; BEHAVIOR; PROBE; FLOW AB Correlation of fast electron current with magnetohydrodynamic activities is studied extensively in the edge of a reversed-field pinch (RFP) plasma in TPE-1RM20 using a complex probe in order to examine the origin of the driving force for fast electrons in RFP plasma. The East electron current is found to have a statistically meaningful coherence with the v x b dynamo electric field. However, the coherence is small and the fast electron current has finite correlations with the global magnetic modes which rotate toroidally and poloidally. Correlation with the externally applied electric field is also examined and is found to be small. Overall correlation studies are discussed in terms of the possible driving sources of fast electrons. C1 Electrotech Lab, Tsukuba, Ibaraki 3058586, Japan. Consorzio RFX, I-35127 Padua, Italy. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Yagi, Y (reprint author), Electrotech Lab, 1-1-4 Umezono, Tsukuba, Ibaraki 3058586, Japan. NR 32 TC 0 Z9 0 U1 0 U2 0 PU JAPAN SOC APPLIED PHYSICS PI TOKYO PA KUDAN-KITA BUILDING 5TH FLOOR, 1-12-3 KUDAN-KITA, CHIYODA-KU, TOKYO, 102-0073, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Brief Commun. Rev. Pap. PD JUL PY 1999 VL 38 IS 7A BP 4213 EP 4225 DI 10.1143/JJAP.38.4213 PG 13 WC Physics, Applied SC Physics GA 248MD UT WOS:000083278000051 ER PT J AU Vitello, P AF Vitello, P TI Pre-sheaths and turbulent flow in electronegative plasmas SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article; Proceedings Paper CT 4th International Conference on Reactive Plasmas (ICRP-4) CY OCT 19-23, 1998 CL MAUI, HAWAII SP Japan Soc Appl Physics DE electronegative plasma; coulomb scattering; boundary layer; turbulent flow; chlorine discharge; inductively coupled plasma ID INDUCTIVELY-COUPLED PLASMA; MOLECULAR CHLORINE; DISCHARGE; ATOMS; MODEL AB In electronegative plasmas Coulomb scattering between positive and negative ions can lead to the formation of a presheath boundary layer containing the bulk of the negative ions. This boundary layer may be unstable, showing time dependent turbultent behavior. The negative ion boundary layer forms when collisional momentum transfer for negative ions is dominated by Coulomb scattering between ions, rather than ion scattering with neutrals. This condition is met in Inductively Coupled Plasma reactors that operate at low pressure and high plasma density. Numerical simulations of a chlorine discharge in a Gaseous Electronics Conference reference cell modified for inductive plasma operation are presented using the INDUCT95 2D model. The behavior of the pre-sheath boundary layer structure as a function of applied power and neutral pressure is shown. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Vitello, P (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 20 TC 9 Z9 9 U1 0 U2 0 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO, 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD JUL PY 1999 VL 38 IS 7B BP 4283 EP 4290 DI 10.1143/JJAP.38.4283 PG 8 WC Physics, Applied SC Physics GA 241FE UT WOS:000082871400006 ER PT J AU Matsubara, I Paranthaman, M Chirayil, TG Sun, EY Martin, PM Kroeger, DM Verebelyi, DT Christen, DK AF Matsubara, I Paranthaman, M Chirayil, TG Sun, EY Martin, PM Kroeger, DM Verebelyi, DT Christen, DK TI Preparation of epitaxial YbBa2Cu3O7-delta on SrTiO3 single crystal substrates using a solution process SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE Yb-123 films; solution process; textured films; critical current density ID DIPPING-PYROLYSIS PROCESS; CRITICAL-CURRENT DENSITY; SOL-GEL SYNTHESIS; SUPERCONDUCTING PROPERTIES; FILMS; DEPOSITION; GROWTH; TAPES AB We have prepared YbBa2Cu3O7-delta (Yb-123) epitaxial films on SrTiO3 (100) single crystal substrates by a metal organic decomposition (MOD) method. Precursor solution was prepared by dissolving ytterbium acetylacetonate, barium neodecanoate, and copper (II) 2-ethylhexanoate in a mixture of solvents containing toluene/pyridine/propionic acid. The precursor solutions were spin coated on the substrates and fired at 730-770 degrees C in 100-ppm oxygen atmospheres followed by I atm Oz annealing. X-ray diffraction results from the theta-2theta, phi, and omega scans for the films revealed a (100) cubic texture. The full-width-at-half-maximum values for Yb-123 (103) and Yb-123 (005) were 1.5 degrees (in-plane epitaxy, Delta phi) and 0.73 degrees (out-of-plane epitaxy, Delta omega), respectively. The highest T-c obtained for Yb-123 films was 87.2K. The measured transport J(c) was 6.4 x 10(5) A/cm(2) at 77 K and self-field. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Matsubara, I (reprint author), Osaka Natl Res Inst, Ikeda, Osaka 5638577, Japan. RI Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 16 TC 8 Z9 8 U1 1 U2 4 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO, 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD JUL 1 PY 1999 VL 38 IS 7A BP L727 EP L730 DI 10.1143/JJAP.38.L727 PG 4 WC Physics, Applied SC Physics GA 218XU UT WOS:000081579000012 ER PT J AU Hull, JR AF Hull, JR TI Using high-temperature superconductors for levitation applications SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID BA-CU-O; ENERGY-STORAGE SYSTEMS; MAGNETIC BEARINGS; PERMANENT-MAGNETS; LOW-FRICTION; FIELD; YBA2CU3O7-DELTA; DEPENDENCE; STIFFNESS; FORCE AB Melt-textured, bulk high-temperature superconductors are finding increasing uses in superconducting bearings, flywheel energy storage, and other levitational applications. This article reviews the use of these materials irt magnetic-levitation applications. The behavior of levitational force, stiffness, damping, and rotational losses is discussed. C1 Argonne Natl Lab, Div Energy Technol, Electromech & Superconduct Sect, Argonne, IL 60439 USA. RP Hull, JR (reprint author), Argonne Natl Lab, Div Energy Technol, Electromech & Superconduct Sect, ET-335, Argonne, IL 60439 USA. NR 76 TC 7 Z9 7 U1 1 U2 9 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD JUL PY 1999 VL 51 IS 7 BP 13 EP 18 DI 10.1007/s11837-999-0101-z PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 213VX UT WOS:000081294900002 ER PT J AU Goyal, A Feenstra, R List, FA Paranthaman, M Lee, DF Kroeger, DM Beach, DB Morrell, JS Chirayil, TG Verebelyi, DT Cui, X Specht, ED Christen, DK Martin, PM AF Goyal, A Feenstra, R List, FA Paranthaman, M Lee, DF Kroeger, DM Beach, DB Morrell, JS Chirayil, TG Verebelyi, DT Cui, X Specht, ED Christen, DK Martin, PM TI Using RABiTS to fabricate high-temperature superconducting wire SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID ELECTRON-BEAM EVAPORATION; BUFFER LAYERS; GRAIN-BOUNDARIES; THICK-FILMS; BICRYSTALS; DEPOSITION; NI AB In order for many large-scale bulk applications of high-temperature superconducting materials to be realized, the cost/performance of the superconductors needs to be optimized. From a performance standpoint, a long flexible, single-crystal-like wire is required; from a cost-and-fabrication standpoint, an industrially scalable, low-cost process is required. Both of these critical requirements are met by Polling-assisted biaxially textured substrates, a conductor-fabrication technique that employs simple, scalable, thermomechanical processing techniques to obtain a near-single-crystal-like, flexible metal substrate in arbitrary lengths on which epitaxial oxide buffer layers and superconductors are then deposited. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Goyal, A (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6116, Oak Ridge, TN 37831 USA. RI Specht, Eliot/A-5654-2009; Paranthaman, Mariappan/N-3866-2015 OI Specht, Eliot/0000-0002-3191-2163; Paranthaman, Mariappan/0000-0003-3009-8531 NR 22 TC 31 Z9 31 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD JUL PY 1999 VL 51 IS 7 BP 19 EP 23 DI 10.1007/s11837-999-0102-y PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 213VX UT WOS:000081294900003 ER PT J AU Cheng, MD Nash, TM Kopetz, SE AF Cheng, MD Nash, TM Kopetz, SE TI Retrieval of aerosol optical thickness by means of the least-median-squares robust algorithm SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID ANTHROPOGENIC AEROSOLS; DEPTH MEASUREMENTS; WATER-VAPOR; RADIATION; CLIMATE; AIR AB Atmospheric aerosols play an active role in the atmospheric radiative energy transfer by interacting with the solar energy through light scattering and/or absorption. Such an interaction has the potential to counter balance or enhance the warming caused by the greenhouse gases (e.g, carbon dioxide, water vapor, and methane). The interactions would depend on a variety of factors such as the microphysics and chemistry of aerosol particles, and the environmental conditions. To model the energy transfer processes accurately, several aerosol parameters such as aerosol optical thickness (AOT), single scattering albedo, scattering phase function, refractive index, and chemical composition of aerosols have to be known. In this report, a robust method for aerosol optical thickness is presented. The method is based on the least median squares (LMS) regression technique. The LMS-based technique is fundamentally different From the traditional least-squares (LS) technique commonly used today to retrieve AOT. The LMS technique was found to resist influential outliers and sustain the impacts of outliers much better than the LS in our application. The outlier-resistance property is an important design consideration for an automatic AOT retrieval algorithm. We demonstrated the strength of the new technique by using the shortwave irradiance measurements taken by one of the Multi-filter Rotating Shadow-band Radiometers installed at the Southern Great Plains in Oklahoma, U.S.A., one of the three sites operated by the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program. The data cover a time period from September 1995 to May 1997. The LMS-retrieved mean top-of-atmosphere solar irradiance values (i.e. I-o) were stable based on the one-tailed Student's t tests. It was also found that the difference between the 75th and 25th percentiles (a non-parametric robust estimate of variation) of I-o over the 2-year period was 0.2 for the 499-nm channel, and 0.05 for the 860-nm channel. The monthly averaged AOT values over the 2-year period were from 0.05 to 0.30 for the 499-nm channel and from 0.03 to 0.15 for the 860-nm channels. AOT values peaked between May and September and reached minima in between November and January. The synoptic flow from the North might have contributed to the low level of AOT values during the wintertime, while the southerly flow, traversing through more industrial areas before reaching the site, could have contributed to the influx of particles during the summertime. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Johns Hopkins Univ, Baltimore, MD 21205 USA. RP Cheng, MD (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Cheng, Meng-Dawn/C-1098-2012; OI Kopetz, Scott/0000-0001-9647-3416; Cheng, Meng-Dawn/0000-0003-1407-9576 NR 39 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD JUL PY 1999 VL 30 IS 6 BP 805 EP 817 DI 10.1016/S0021-8502(98)00765-4 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 187KC UT WOS:000079784900009 ER PT J AU Maya, L Brown, GM Thundat, T AF Maya, L Brown, GM Thundat, T TI Porous platinum electrodes derived from the reduction of sputtered platinum dioxide films SO JOURNAL OF APPLIED ELECTROCHEMISTRY LA English DT Article DE platinum electrodes; platinum oxide; porous electrodes; sputtering ID DEPOSITION; CARBON C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Maya, L (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 13 TC 4 Z9 5 U1 1 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0021-891X J9 J APPL ELECTROCHEM JI J. Appl. Electrochem. PD JUL PY 1999 VL 29 IS 7 BP 883 EP 888 PG 6 WC Electrochemistry SC Electrochemistry GA 209EQ UT WOS:000081035600013 ER PT J AU Pearton, SJ Zolper, JC Shul, RJ Ren, F AF Pearton, SJ Zolper, JC Shul, RJ Ren, F TI GaN: Processing, defects, and devices SO JOURNAL OF APPLIED PHYSICS LA English DT Review ID N-TYPE GAN; FIELD-EFFECT TRANSISTORS; QUANTUM-WELL-STRUCTURE; STRUCTURE LASER-DIODES; CHEMICAL-VAPOR-DEPOSITION; CONTINUOUS-WAVE OPERATION; MOLECULAR-BEAM EPITAXY; LIGHT-EMITTING-DIODES; III-V NITRIDES; INDUCTIVELY-COUPLED PLASMA AB The role of extended and point defects, and key impurities such as C, O, and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation, and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes, and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics. (C) 1999 American Institute of Physics. [S0021-8979(99)00613-1]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Off Naval Res, Arlington, VA 22217 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. EM spear@mse.ufl.edu NR 610 TC 1187 Z9 1230 U1 60 U2 541 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 1 EP 78 DI 10.1063/1.371145 PG 78 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300001 ER PT J AU Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Heske, C van Buuren, T Dinh, VV Lee, HW Pakbaz, K Fox, G Jimenez, I AF Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Heske, C van Buuren, T Dinh, VV Lee, HW Pakbaz, K Fox, G Jimenez, I TI X-ray photoemission and photoabsorption of organic electroluminescent materials SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LIGHT-EMITTING-DIODES; INTERFACIAL ELECTRONIC-STRUCTURES; CORE-LEVEL PHOTOABSORPTION; UV PHOTOEMISSION; THIN-FILMS; SEMICONDUCTOR HETEROJUNCTIONS; BLUE ELECTROLUMINESCENCE; METAL INTERFACES; DEVICES; SPECTROSCOPY AB Thin films of tris-(8, hydroxyquinoline) aluminum (Alq(3)) and N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) were measured using synchrotron radiation-based core and valence level photoemission and core level photoabsorption to elucidate the element-specific electronic structure of organic electroluminescent materials. The energy level alignment of an Alq(3)/TPD interface is given for both occupied and unoccupied states. A comparison of freshly evaporated films of Alq(3) and TPD with films that have been exposed to intense radiation or oxidative conditions sheds light on possible damage mechanisms of the molecular solid. (C) 1999 American Institute of Physics. [S0021-8979(99)03613-0]. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Treusch, R (reprint author), DESY, HASYLAB, D-22603 Hamburg, Germany. RI Jimenez, Ignacio/F-7422-2010; Treusch, Rolf/C-3935-2015; OI Jimenez, Ignacio/0000-0001-5605-3185; Treusch, Rolf/0000-0001-8479-8862 NR 51 TC 31 Z9 31 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 88 EP 93 DI 10.1063/1.370703 PG 6 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300003 ER PT J AU Viecelli, JA Ree, FH AF Viecelli, JA Ree, FH TI Carbon clustering kinetics in detonation wave propagation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MIXTURES AB Much of the nonideality of insensitive carbon rich explosives such as TATB is thought to be caused by a late-time slow release of energy associated with diffusion limited growth of carbon clusters. We have adapted Shaw and Johnson's approximate analytic solution of the Smoluchowski rate equations for the evolution of the cluster size distribution function for use in hydrodynamic calculations and in Wood and Kirkwood approximate theory for the detonation velocity-curvature relationship. Solutions for the effect of carbon cluster growth on the structure of the reaction zone are obtained, and the results are compared with available experimental data. (C) 1999 American Institute of Physics. [S0021-8979(99)05613-3]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Viecelli, JA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 20 TC 17 Z9 18 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 237 EP 248 DI 10.1063/1.370722 PG 12 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300024 ER PT J AU Withrow, SP White, CW Meldrum, A Budai, JD Hembree, DM Barbour, JC AF Withrow, SP White, CW Meldrum, A Budai, JD Hembree, DM Barbour, JC TI Effects of hydrogen in the annealing environment on photoluminescence from Si nanoparticles in SiO2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ION-BEAM SYNTHESIS; SILICON NANOCRYSTALS; OPTICAL-PROPERTIES; IMPLANTED SIO2; LUMINESCENCE; SIO2-FILMS; NANOSTRUCTURES; DIFFUSION; INTERFACE; EMISSION AB The role of hydrogen in enhancing the photoluminescence (PL) yield observed from Si nanocrystals embedded in SiO2 has been studied. SiO2 thermal oxides and bulk fused silica samples have been implanted with Si and subsequently annealed in various ambients including hydrogen or deuterium forming gases (Ar+4%H-2 or Ar+4%D-2) or pure Ar. Results are presented for annealing at temperatures between 200 and 1100 degrees C. Depth and concentration profiles of H and D at various stages of processing have been measured using elastic recoil detection. Hydrogen or deuterium is observed in the bulk after annealing in forming gas but not after high temperature (1100 degrees C) anneals in Ar. The presence of hydrogen dramatically increases the broad PL band centered in the near infrared after annealing at 1100 degrees C but has almost no effect on the PL spectral distribution. Hydrogen is found to selectively trap in the region where Si nanocrystals are formed, consistent with a model of H passivating surface states at the Si/SiO2 interface that leads to enhanced PL. The thermal stability of the trapped H and the PL yield observed after a high temperature anneal have been studied. The hydrogen concentration and PL yield are unchanged for subsequent anneals up to 400 degrees C. However, above 400 degrees C the PL decreases and a more complicated H chemistry is evident. Similar concentrations of H or D are trapped after annealing in H-2 or D-2 forming gas; however, no differences in the PL yield or spectral distribution are observed, indicating that the electronic transitions resulting in luminescence are not dependent on the mass of the hydrogen species. (C) 1999 American Institute of Physics. [S0021-8979(99)07913-X]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Oak Ridge Y12 Plant, Oak Ridge, TN 37831 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Withrow, SP (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 27 TC 115 Z9 117 U1 0 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 396 EP 401 DI 10.1063/1.370699 PG 6 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300047 ER PT J AU Pecharsky, VK Gschneidner, KA AF Pecharsky, VK Gschneidner, KA TI Magnetocaloric effect from indirect measurements: Magnetization and heat capacity SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ROOM-TEMPERATURE; REFRIGERATOR AB Accurate values for the magnetocaloric effect can be obtained from both magnetization and heat-capacity data. A reliable estimate of the experimental errors in the calculated magnetocaloric effect can be made from the known experimental errors of the measured physical properties. Attempts in the past to simplify the basic thermodynamic relation to allow the calculation of the adiabatic temperature change from the heat capacity at constant field and the magnetic entropy change calculated from the magnetization data fail because the assumption that heat capacity is magnetic-field independent is erroneous. A suitable approach to carry out these calculations from the combined heat capacity and magnetization data is suggested. (C) 1999 American Institute of Physics. [S0021-8979(99)04013-X]. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Pecharsky, VK (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 25 TC 412 Z9 418 U1 9 U2 61 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 565 EP 575 DI 10.1063/1.370767 PG 11 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300073 ER PT J AU Rohlsberger, R Sturhahn, W Toellner, TS Quast, KW Hession, P Hu, M Sutter, J Alp, EE AF Rohlsberger, R Sturhahn, W Toellner, TS Quast, KW Hession, P Hu, M Sutter, J Alp, EE TI Phonon damping in thin films of Fe SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID NUCLEAR RESONANT SCATTERING; SYNCHROTRON-RADIATION; RESOLUTION AB The phonon density of states (DOS) in thin films of polycrystalline alpha-Fe was measured by inelastic nuclear resonant scattering of synchrotron radiation. The thin-film DOS exhibits significant deviations from the DOS of bulk Fe, which we attribute to phonon lifetime broadening in the confined geometry. The measured DOS can be described with a damped harmonic oscillator model for the phonons with different quality factors Q=25(2) and Q=13(1) for layer thicknesses of 28 and 13 nm, respectively. (C) 1999 American Institute of Physics. [S0021-8979(99)08413-3]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Rohlsberger, R (reprint author), Univ Rostock, August Bebel Str 55, D-18051 Rostock, Germany. RI Rohlsberger, Ralf/J-4173-2013 OI Rohlsberger, Ralf/0000-0001-6005-5183 NR 20 TC 34 Z9 35 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 584 EP 587 PG 4 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300076 ER PT J AU Anovitz, LM Elam, JM Riciputi, LR Cole, DR AF Anovitz, LM Elam, JM Riciputi, LR Cole, DR TI The failure of obsidian hydration dating: Sources, implications, and new directions SO JOURNAL OF ARCHAEOLOGICAL SCIENCE LA English DT Review DE obsidian; secondary ion mass spectrometry; SIMS; diffusion; hydration dating; glass; Becke line; anisotropy; finite difference modelling; Chalco; Copan; Xaltocan; Mesoamerica; Matano interface ID SILICA GLASS; WATER DIFFUSION; LOW-TEMPERATURE; RATES; MECHANISMS; HYDROGEN; MELTS; AGE C1 Oak Ridge Nat Lab, Chem & Analytical Sci Div, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Anthropol, Knoxville, TN 37996 USA. RP Anovitz, LM (reprint author), Oak Ridge Nat Lab, Chem & Analytical Sci Div, PO Box 2008 Bldg 4500s, Oak Ridge, TN 37831 USA. OI Anovitz, Lawrence/0000-0002-2609-8750 NR 106 TC 78 Z9 78 U1 1 U2 13 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0305-4403 J9 J ARCHAEOL SCI JI J. Archaeol. Sci. PD JUL PY 1999 VL 26 IS 7 BP 735 EP 752 DI 10.1006/jasc.1998.0342 PG 18 WC Anthropology; Archaeology; Geosciences, Multidisciplinary SC Anthropology; Archaeology; Geology GA 218AX UT WOS:000081532100002 ER PT J AU Clothiaux, EE Moran, KP Martner, BE Ackerman, TP Mace, GG Uttal, T Mather, JH Widener, KB Miller, MA Rodriguez, DJ AF Clothiaux, EE Moran, KP Martner, BE Ackerman, TP Mace, GG Uttal, T Mather, JH Widener, KB Miller, MA Rodriguez, DJ TI The atmospheric radiation measurement program cloud radars: Operational modes SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SIZE DISTRIBUTIONS; COMPLEMENTARY CODE AB During the past decade, the U.S. Department of Energy (DOE), through the Atmospheric Radiation Measurement (ARM) Program, has supported the development of several millimeter-wavelength radars for the study of clouds. This effort has culminated in the development and construction of a 35-GHz radar system by the Environmental Technology Laboratory (ETL) of the National Oceanic and Atmospheric Administration (NOAA). Radar systems based on the NOAA ETL design are now operating at the DOE ARM Southern Great Plains central facility in central Oklahoma and the DOE ARM North Slope of Alaska site near Barrow, Alaska. Operational systems are expected to come online within the next year at the DOE ARM tropical western Pacific sites located at Manus, Papua New Guinea, and Nauru. In order for these radars to detect the full range of atmospheric hydrometeors, specific modes of operation must be implemented on them that are tuned to accurately detect the reflectivities of specific types of hydrometeors. The set of four operational modes that are currently in use on these radars are presented and discussed. The characteristics of the data produced by these modes of operation are also presented in order to illustrate the nature of the cloud products that are, and will be, derived from them on a continuous basis. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NOAA, Environm Technol Lab, Boulder, CO USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Batelle, Pacific NW Natl Lab, Richland, WA USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Calif Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA USA. RP Clothiaux, EE (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. NR 14 TC 63 Z9 65 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUL PY 1999 VL 16 IS 7 BP 819 EP 827 DI 10.1175/1520-0426(1999)016<0819:TARMPC>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 217PG UT WOS:000081507700002 ER PT J AU Huang, XL Link, K Koide, A Dunn, JJ Luft, BJ Koide, S AF Huang, XL Link, K Koide, A Dunn, JJ Luft, BJ Koide, S TI H-1, C-13, and N-15 NMR backbone assignments of 37 kDa surface antigen OspC from Borrelia burgdorferi SO JOURNAL OF BIOMOLECULAR NMR LA English DT Article DE deuteration; lyme disease; outer surface proteins; vaccine design ID PROTEINS; COMPLEX C1 Univ Rochester, Med Ctr, Dept Biochem & Biophys, Rochester, NY 14642 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. SUNY Stony Brook, Sch Med, Div Infect Dis, Stony Brook, NY 11794 USA. RP Koide, S (reprint author), Univ Rochester, Med Ctr, Dept Biochem & Biophys, Rochester, NY 14642 USA. FU NIAID NIH HHS [AI3756] NR 10 TC 9 Z9 10 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0925-2738 J9 J BIOMOL NMR JI J. Biomol. NMR PD JUL PY 1999 VL 14 IS 3 BP 283 EP 284 DI 10.1023/A:1008398527355 PG 2 WC Biochemistry & Molecular Biology; Spectroscopy SC Biochemistry & Molecular Biology; Spectroscopy GA 220XC UT WOS:000081692800010 PM 10481278 ER PT J AU Au-Yeung, J Bell, AT Iglesia, E AF Au-Yeung, J Bell, AT Iglesia, E TI The dynamics of oxygen exchange with zirconia-supported PdO SO JOURNAL OF CATALYSIS LA English DT Article ID ISOTOPIC EXCHANGE; METHANE; CATALYSTS; COMBUSTION; PALLADIUM; OXIDATION; ACTIVATION; ADSORPTION; SIZE AB Isotopic tracer methods involving O-18 and O-16 were used to investigate the dynamics of O-2 adsorption and desorption from the surface of zirconia-supported PdO and the dynamics of O atom diffusion through the bulk of PdO. The rate coefficient for the recombination of O atoms is found to be 1.4 x 10(13) exp(-144,000/RT) s(-1) and the diffusivity of O atoms through bulk PdO is 1.6 x 10(-10) exp(-89,000/RT) cm(2)/s. In both cases, the activation energies are in units of kJ/mol. While oxygen exchange with pure ZrO2 was not observed under the conditions of the present experiments, such exchange did occur to a limited degree when PdO was supported on ZrO2, the degree of exchange increasing with decreasing PdO particle size. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, 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, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017; OI Iglesia, Enrique/0000-0003-4109-1001; Bell, Alexis/0000-0002-5738-4645 NR 22 TC 23 Z9 23 U1 0 U2 6 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 JUL 1 PY 1999 VL 185 IS 1 BP 213 EP 218 DI 10.1006/jcat.1999.2512 PG 6 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 210ZM UT WOS:000081135500020 ER PT J AU Ally, MR AF Ally, MR TI Solute and solvent activities of CaCl2(aq) solutions from the adsorption isotherm treatment SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID CONCENTRATED-SOLUTIONS; ACTIVITY-COEFFICIENTS; BET MODEL; WATER; ELECTROLYTES; SALTS AB The values of the two Brunauer-Emmett-Teller (BET) parameters calculated by Stokes and Robinson (1948) are reevaluated using recent experimental, data on the activity coefficients of CaCl2(aq) reported by Rard and Clegg (1997). At the 95% confidence level, no significant statistical differences are observed in the values df the BET parameters reported in this work and those reported by Stokes and Robinson (1948). The water activities a,, osmotic coefficients phi, and mean ionic activity coefficients, gamma(+/-) of CaCl2(aq) are then calculated from saturation to dilute solution. Since the standard state of the solute in the 1 BET model is the anhydrous liquid electrolyte rather than: the infinitely dilute solution, the technique of Ally and Braunstein (1996) is utilized to obtain the mean ionic activity coefficients of CaCl2(aq) over the, entire concentration range. The differences between the chemical potentials of the solute in the infinitely dilute solution standard state (hypothetical) and the anhydrous liquid electrolyte standard state (hypothetical) are shown to remain constant, as must be, since, the standard states are fixed at a given temperature. The ability of the model to predict a(w), phi, and gamma(+/-) with only two parameters is reported. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Ally, MR (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. NR 11 TC 13 Z9 13 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD JUL-AUG PY 1999 VL 44 IS 4 BP 792 EP 797 DI 10.1021/je980296c PG 6 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 216ZA UT WOS:000081473300024 ER PT J AU Davies, JA LeClaire, JE Continetti, RE Hayden, CC AF Davies, JA LeClaire, JE Continetti, RE Hayden, CC TI Femtosecond time-resolved photoelectron-photoion coincidence imaging studies of dissociation dynamics SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-STATES; LASER-PULSES; SPECTROSCOPY; NO2; PHOTODISSOCIATION; IONIZATION; ABSORPTION; MOLECULES; THRESHOLD; CLUSTERS AB We present the first results using a new technique that combines femtosecond pump-probe methods with energy- and angle-resolved photoelectron-photoion coincidence imaging. The dominant dissociative multiphoton ionization (DMI) pathway for NO2 at 375.3 nm is identified as three-photon excitation to a repulsive potential surface correlating to NO(C (2)Pi)+O(P-3) followed by one-photon ionization to NO+(X (1)Sigma(+)). Dissociation along this surface is followed on a femtosecond timescale. (C) 1999 American Institute of Physics. [S0021-9606(99)02525-8]. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. RP Hayden, CC (reprint author), Sandia Natl Labs, Combust Res Facil, POB 969, Livermore, CA 94551 USA. OI Continetti, Robert/0000-0002-0685-4459 NR 22 TC 160 Z9 162 U1 3 U2 41 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 1999 VL 111 IS 1 BP 1 EP 4 DI 10.1063/1.479248 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 208MQ UT WOS:000080995500001 ER PT J AU Yang, M Fleming, GR AF Yang, M Fleming, GR TI Third-order nonlinear optical response of energy transfer systems SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOSYNTHETIC ANTENNA COMPLEXES; POLAR SOLVATION DYNAMICS; PHOTON-ECHO MEASUREMENTS; RHODOBACTER-SPHAEROIDES; FLUORESCENCE DEPOLARIZATION; EXCITATION TRANSFER; B820 SUBUNIT; PEAK SHIFT; PROBE; SPECTROSCOPIES AB The third-order nonlinear optical response of energy transfer systems is theoretically investigated. A system composed of two chromophores having the same electronic transition energies is considered. The dynamics of energy transfer between the two chromophores is assumed to occur via a hopping (incoherent) mechanism. We introduce new types of pathways incorporating the hopping processes occurring while the system is in population states and reconstruct a third-order response function which is computationally viable. The nuclear propagators in the electronic population states are written as convolution integrals between those of the nonreactive two-state system weighted by some factors for the energy transfer. The response function is given by multitime correlation functions and these are analyzed by the cumulant expansion method. Based on this approach, the three-pulse photon echo peak shift for several models of energy transfer systems is discussed. It is shown that the rephasing capability of the induced signal is reduced by the memory loss due to resonant energy transfer. A previous model which incorporates resonant energy transfers in an intuitive way is reviewed and modified to supplement the loss of dynamic correlation of nuclear motion within the framework of the theory. The response function obtained by our new approach gives a more accurate description than the existing theory and a comparative discussion is given. The effect of inhomogeneity in rate constants on the third-order signal is discussed and the temperature dependence of the echo signal is examined. (C) 1999 American Institute of Physics. [S0021-9606(99)01325-2]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biophys Div, Berkeley, CA 94720 USA. RP Yang, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. OI Yang, Mino/0000-0001-9504-0280 NR 32 TC 46 Z9 48 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 1999 VL 111 IS 1 BP 27 EP 39 DI 10.1063/1.479359 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 208MQ UT WOS:000080995500006 ER PT J AU Sorkhabi, O Qi, F Rizvi, AH Suits, AG AF Sorkhabi, O Qi, F Rizvi, AH Suits, AG TI Ultraviolet photodissociation of furan probed by tunable synchrotron radiation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THERMAL-DECOMPOSITION; UNIMOLECULAR DECOMPOSITION; AB-INITIO; 193 NM; ISOXAZOLE; PHOTOIONIZATION; DISSOCIATION; SPECTROSCOPY; ABSORPTION; PYROLYSIS AB The photodissociation dynamics of furan at 193 nm have been studied using photofragment translational spectroscopy with tunable vacuum ultraviolet (VUV) probe provided by synchrotron radiation on the Chemical Dynamics Beamline at the Advanced Light Source. Three primary channels are observed: HCO+C3H3, CO+C3H4, and H2CCO+C2H2. The evidence suggests that the two closed-shell channels occur on the ground-state potential energy surface (PES) following internal conversion, while the radical channel likely takes place on an excited PES. All channels exhibit a barrier for dissociation with the acetylene+ketene channel having the largest value at about 25 kcal/mol. Angular distribution measurements show anisotropy only for the radical channel. These findings are consistent with a rapid excited state dissociation for the radical channel and slow dissociation for the other two pathways. The two ground-state dissociation channels-propyne+CO and acetylene+ketene-should be important in the thermal decomposition of furan as was found in pyrolytic studies [A. Lifshitz, M. Bidani, and S. Bidani, J. Phys. Chem. 90, 5373 (1986)] and theoretical investigations [R. Liu, X. Zhou, and L. Zhai, J. Comput. Chem. 19, 240 (1998)]. (C) 1999 American Institute of Physics. [S0021-9606(99)01625-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Sorkhabi, O (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Qi, Fei/A-3722-2012 NR 24 TC 29 Z9 29 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 1999 VL 111 IS 1 BP 100 EP 107 DI 10.1063/1.479257 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 208MQ UT WOS:000080995500014 ER PT J AU Haslam, AJ Jackson, G McLeish, TCB AF Haslam, AJ Jackson, G McLeish, TCB TI An investigation of the shape and crossover scaling of flexible tangent hard-sphere polymer chains by Monte Carlo simulation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RANDOM NUMBER GENERATORS; COMPUTER-SIMULATION; CHEMICAL-POTENTIALS; SYSTEMS; DIMENSIONS; DEPENDENCE; MOLECULES; EFFICIENT; DYNAMICS; DENSITY AB Results are presented from our simulation study of flexible, tangent hard-sphere polymer chains, using a Monte Carlo technique with a reptation algorithm. We examine the crossover region from the swollen (dilute) region to the semidilute regime using chains of degree up to N=2000. The (average) chain end-to-end distance is analyzed as a function of the number of chain links, as is a correlation function for the internal separation of segments, expressed in terms of their connectivity. We study the structure of the polymer chains using scattering functions, which are presented in addition to the segment-segment distribution functions from which they are calculated. Not surprisingly, the Flory exponent nu changes gradually from the dilute value of nu approximate to 0.59 to approximate to 1/2 at high density. We find that for chains of 2000 segments, this transition begins at the very low molecular volume fraction of about 0.1%. An analysis of the correlation function for internal segments provides a similar but more detailed picture, in that the role of the screening length xi becomes explicit. The pair distribution and scattering functions in the swollen, crossover, and melt regions are determined and the scaling behavior is reexamined in the context of these functions. The system considered will form a reference system for subsequent studies in which the model will be broadened to include a network and/or attractive interactions. In this paper we seek first of all to establish that reference, and to relate our work to previous studies in this area of interest. As an important technical point, we also note that the use of an inappropriate random number generator can cause the complete failure of simulations of this type. (C) 1999 American Institute of Physics. [S0021-9606(99)50424-8]. C1 Univ Sheffield, Dept Chem, Sheffield S3 7HF, S Yorkshire, England. Univ London Imperial Coll Sci Technol & Med, Dept Chem Engn & Chem Technol, London SW7 2BY, England. Univ Leeds, IRC Polymer Sci & Technol, Leeds LS2 9JT, W Yorkshire, England. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. RP Haslam, AJ (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Jackson, George/D-3649-2015; OI Jackson, George/0000-0002-8029-8868; McLeish, Tom/0000-0002-2025-0299 NR 53 TC 10 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 1999 VL 111 IS 1 BP 416 EP 428 DI 10.1063/1.479292 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 208MQ UT WOS:000080995500049 ER PT J AU Leung, LR Ghan, SJ AF Leung, LR Ghan, SJ TI Pacific Northwest climate sensitivity simulated by a regional climate model driven by a GCM. Part I: Control simulations SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; OROGRAPHIC PRECIPITATION; SPATIAL VARIABILITY; BOUNDARY-LAYER; CCM3; PARAMETERIZATION; RESOLUTION; LAKE AB A model nesting approach has been used to simulate the regional climate over the Pacific Northwest. The present-day global climatology is first simulated using the NCAR Community Climate Model (CCM3) driven by observed sea surface temperature and sea ice distribution at T42 (2.8 degrees) resolution. This large-scale simulation is used to provide lateral boundary conditions for driving the Pacific Northwest National Laboratory Regional Climate Model (RCM). One notable feature of the RCM is the use of subgrid parameterizations of orographic precipitation and vegetation cover, in which subgrid variations of surface elevation and vegetation are aggregated to a limited number of elevation-vegetation classes. An airflow model and a thermodynamic model are used to parameterize the orographic uplift/descent as air parcels cross over mountain barriers or valleys. The 7-yr climatologies as simulated by CCM3 and RCM are evaluated and compared in terms of large-scale spatial patterns and regional means. Biases are found in the simulation of large-scale circulations, which also affect the regional model simulation. Therefore, the regional simulation is not very different from the CCM3 simulation in terms of large-scale features. However, the regional model greatly improves the simulation of precipitation, surface temperature, and snow cover at the local scales. This is shown by improvements in the spatial correlation between the observations and simulations. The RCM simulation is further evaluated using station observations of surface temperature and precipitation to compare the simulated and observed relationships between surface temperature-precipitation and altitude. The model is found to correctly capture the surface temperature-precipitation variations as functions of surface topography over different mountain ranges, and under different climate regimes. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Leung, LR (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. RI Ghan, Steven/H-4301-2011 OI Ghan, Steven/0000-0001-8355-8699 NR 39 TC 67 Z9 69 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1999 VL 12 IS 7 BP 2010 EP 2030 DI 10.1175/1520-0442(1999)012<2010:PNCSSB>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700010 ER PT J AU Leung, LR Ghan, SJ AF Leung, LR Ghan, SJ TI Pacific northwest climate sensitivity simulated by a regional climate model driven by a GCM. Part II: 2xCO(2) simulations SO JOURNAL OF CLIMATE LA English DT Article ID WATER-RESOURCES; ATMOSPHERIC CO2 AB Global climate change due to increasing concentrations of greenhouse gases has stimulated numerous studies and discussions about its possible impacts on water resources. Climate scenarios generated by climate models at spatial resolutions ranging from about 50 km to 400 km may not provide enough spatial specificity for use in impact assessment. In Parts I and II of this paper. the spatial specificity issue is addressed by examining what information on mesoscale and small-scale spatial features can be gained by using a regional climate model with a subgrid parameterization of orographic precipitation and land surface cover, driven by a general circulation model. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. This paper describes and contrasts the large-scale and mesoscale features of the greenhouse warming climate signals simulated by the general circulation modal and regional climate model over the Pacific Northwest. Results indicate that changes in the large-scale circulation exhibit strong seasonal variability. There is an average warming of about 2 degrees C, and precipitation generally increases over the Pacific Northwest and decreases over California. The precipitation signal over the Pacific Northwest is only statistically significant during spring, when both the change in the large-scale circulation and increase in water vapor enhance the moisture convergence toward the north Pacific coast. The combined effects of surface temperature and precipitation changes are such that snow cover is reduced by up to 50% on average, causing large changes in the seasonal runoff. This paper also describes the high spatial resolution (1.5 km) climate signals simulated by the regional climate model. Reductions in snow cover of 50%-90% are found in areas near the snow line of the control simulation. Analyses of the variations of the climate signals with surface elevation ranging from sea level to 4000 m over two mountain ranges in the Pacific Northwest show that because of changes in the alitude of the freezing level, strong elevation dependency is found in the surface temperature, rainfall. snowfall, snow cover, and runoff signals. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Leung, LR (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. RI Ghan, Steven/H-4301-2011 OI Ghan, Steven/0000-0001-8355-8699 NR 22 TC 82 Z9 86 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1999 VL 12 IS 7 BP 2031 EP 2053 DI 10.1175/1520-0442(1999)012<2031:PNCSSB>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700011 ER PT J AU Fedkiw, RP Aslam, T Merriman, B Osher, S AF Fedkiw, RP Aslam, T Merriman, B Osher, S TI A non-oscillatory Eulerian approach to interfaces in multimaterial flows (the ghost fluid method) SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID EFFICIENT IMPLEMENTATION; HYPERBOLIC SYSTEMS; SCHEMES; RESOLUTION; DYNAMICS AB While Eulerian schemes work well for most gas flows, they have been shown to admit nonphysical oscillations near some material interfaces. In contrast, Lagrangian schemes work well at multimaterial interfaces, but suffer from their own difficulties in problems with large deformations and vorticity characteristic of most gas flows. We believe that the most robust schemes will combine the best properties of Eulerian and Lagrangian schemes. In this paper, we propose a new numerical method for treating interfaces in Eulerian schemes that maintains a Heaviside profile of the density with no numerical smearing along the lines of earlier work and most Lagrangian schemes. We use a level set function to track the motion of a multimaterial interface in an Eulerian framework. In addition, the use of ghost cells (actually ghost nodes in our finite difference framework) and a new isobaric fix technique allows us to keep the density profile from smearing out, while still keeping the scheme robust and easy to program with simple extensions to multidimensions and multilevel time integration, e.g., Runge-Kutta methods. In contrast, previous methods used ill-advised dimensional splitting for multidimensional problems and suffered from great complexity when used in conjunction with multilevel time integrators. (C) 1999 Academic Press. C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Fedkiw, RP (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90095 USA. NR 34 TC 795 Z9 891 U1 6 U2 63 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 JUL 1 PY 1999 VL 152 IS 2 BP 457 EP 492 DI 10.1006/jcph.1999.6236 PG 36 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 215DL UT WOS:000081366600002 ER PT J AU Colella, P Dorr, MR Wake, DD AF Colella, P Dorr, MR Wake, DD TI Numerical solution of plasma fluid equations using locally refined grids SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID INDUCTIVELY-COUPLED PLASMA; ADAPTIVE MESH REFINEMENT; ETCHING REACTORS; MODEL; DISTRIBUTIONS AB This paper describes a numerical method for the solution of plasma fluid equations on block-structured, locally refined grids. The plasmas under consideration are typical of those used for the processing of semiconductors. The governing equations consist of a drift-diffusion model of the electrons, together with an energy equation, coupled via Poisson's equation to a system of Euler equations for each ion species augmented with electric field, collisional, and source/sink terms. A discretization previously developed for a uniform spatial grid is generalized to enable local grid refinement. This extension involves the time integration of the discrete system on a hierarchy of levels, each of which represents a degree of refinement, together with synchronization steps to ensure consistency across levels. This approach represents an advancement of methodologies developed for neutral flows using block-structured adaptive mesh refinement (AMR) to include the significant additional effect of the electrostatic forces that couple the ion and electron fluid components. Numerical results that assess the accuracy and efficiency of the method and illustrate the importance of using adequate resolution are also presented. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Colella, P (reprint author), Lawrence Livermore Natl Lab, POB 808,L-561, Livermore, CA 94551 USA. NR 33 TC 25 Z9 25 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE 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 JUL 1 PY 1999 VL 152 IS 2 BP 550 EP 583 DI 10.1006/jcph.1999.6245 PG 34 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 215DL UT WOS:000081366600005 ER PT J AU He, XY Chen, SY Zhang, RY AF He, XY Chen, SY Zhang, RY TI A lattice Boltzmann scheme for incompressible multiphase flow and its application in simulation of Rayleigh-Taylor instability SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID HYDRODYNAMIC SPINODAL DECOMPOSITION; NAVIER-STOKES EQUATION; PHASE-TRANSITIONS; NONIDEAL GASES; FLUID-FLOWS; MODEL; DYNAMICS AB In this pager, we propose a new lattice Boltzmann scheme for simulation of multiphase flow in the nearly incompressible limit. The new scheme simulates fluid flows based on distribution functions. The interfacial dynamics, such as phase segregation and surface tension, are modeled by incorporating molecular interactions. The lattice Boltzmann equations are derived from the continuous Boltzmann equation with appropriate approximations suitable for incompressible flow. The numerical stability is improved by reducing the effect of numerical errors in calculation of molecular interactions. An index function is used to track interfaces between different phases. Simulations of the two-dimensional Rayleigh-Taylor instability yield satisfactory results. The interface thickness is maintained at 3-4 grid spacings throughout simulations without artificial reconstruction steps. (C) 1999 Academic Press. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP He, XY (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010 NR 38 TC 446 Z9 471 U1 8 U2 85 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL 1 PY 1999 VL 152 IS 2 BP 642 EP 663 DI 10.1006/jcph.1999.6257 PG 22 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 215DL UT WOS:000081366600008 ER PT J AU Rider, WJ Knoll, DA AF Rider, WJ Knoll, DA TI Time step size selection for radiation diffusion calculations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE radiation diffusion; wavespeed; time step size C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Hydrodynam Methods Grp, Los Alamos, NM 87545 USA. RP Rider, WJ (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Hydrodynam Methods Grp, MS D413, Los Alamos, NM 87545 USA. NR 6 TC 16 Z9 16 U1 1 U2 3 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 JUL 1 PY 1999 VL 152 IS 2 BP 790 EP 795 DI 10.1006/jcph.1999.6266 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 215DL UT WOS:000081366600013 ER PT J AU Muramatsu, Y Hayashi, T Perera, RCC AF Muramatsu, Y Hayashi, T Perera, RCC TI Theoretically predicted soft X-ray emission and absorption spectra of fullerene-like carbon nitride (C24N36) SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE carbon nitride; X-ray spectra; electronic structure ID MOLECULAR ORBITAL INTERPRETATION; C-60; SPECTROSCOPY; FILMS AB Theoretical C K and N K X-ray emission/absorption spectra of fullerene-like-structured carbon nitride (C24N36) clusters were obtained using discrete-variational (DV)-X alpha molecular orbital calculations. These calculations predicted that the energy widths of the C K and N K X-ray emission peaks would be about 8 and 6 eV, respectively; three low-energy satellites would appear in each emission spectrum; and there would be a narrow HOMO-LUMO energy gap of 0.38 eV. These theoretically predicted X-ray emission/absorption spectra will be useful in the synthesis and characterisation of fullerene-like carbon nitrides. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NTT, Integrated Informat & Energy Syst Labs, Musashino, Tokyo 1808585, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Muramatsu, Y (reprint author), NTT, Integrated Informat & Energy Syst Labs, 3-9-11 Midori Cho, Musashino, Tokyo 1808585, Japan. NR 21 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD JUL PY 1999 VL 104 IS 1-3 BP 155 EP 160 DI 10.1016/S0368-2048(99)00005-5 PG 6 WC Spectroscopy SC Spectroscopy GA 213ZP UT WOS:000081303400016 ER PT J AU Ohrwall, G Bozek, J Baltzer, P AF Ohrwall, G Bozek, J Baltzer, P TI Very high resolution electron spectroscopy with third generation synchrotron radiation sources: the resonant Auger decay spectrum of the Xe 4d(5/2)(-1)6p state SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE Auger resonant Raman; synchrotron radiation; xenon AB We have recorded an Auger decay spectrum of the resonantly excited Xe 4d(5/2)(-1)6p state between 36.4 and 37.3 eV kinetic energy. The spectrum was obtained under resonant Raman conditions, with a bandwidth of approximate to 6 meV for the exciting radiation, much smaller than the natural lifetime width of 110-120 meV. The full width at half maximum of the peaks in the spectrum was 10 meV, making it possible to completely resolve structure that overlapped in earlier studies. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ohrwall, G (reprint author), Univ Uppsala, Dept Phys, Box 530, S-75121 Uppsala, Sweden. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 12 TC 24 Z9 24 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD JUL PY 1999 VL 104 IS 1-3 BP 209 EP 212 DI 10.1016/S0368-2048(99)00009-2 PG 4 WC Spectroscopy SC Spectroscopy GA 213ZP UT WOS:000081303400021 ER PT J AU Schafer, J Young, AP Levin, TM Brillson, LJ Paggel, JJ Vanzetti, L Franciosi, A AF Schafer, J Young, AP Levin, TM Brillson, LJ Paggel, JJ Vanzetti, L Franciosi, A TI Cathodoluminescence spectroscopy of deep defect levels at the ZnSe/GaAs interface with a composition-control interface layer SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE ZnSe/GaAs; interface stoichiometry; heterovalent interfaces; deep level spectroscopy ID EXCITONIC GAIN; QUANTUM-WELLS; BAND OFFSETS; HETEROSTRUCTURES; ZNSE; GAAS AB In this work we investigate ZnSe/GaAs heterostructures with an additional 2 nm controlled interfacial layer (CIL) of Se- or Zn-rich composition to modify the band offset. The samples are analyzed as a function of annealing temperature by cathodoluminescence spectroscopy. The as-prepared samples show defect luminescence at similar to 0.9 eV, With staged annealing at increasing temperatures, both the Zn-rich as well as the Se-rich interfacial layer exhibits luminescence at similar to 1.9 eV, indicative of defect formation with an onset temperature of similar to 400 degrees C, Excitation-dependent spectroscopy provides evidence for defect formation near the interface, which extends into the ZnSe epilayer at higher temperatures. Compared to earlier work, where the threshold temperature for defect formation in bulk samples fabricated under Se-rich growth conditions occurs at temperatures as low as 325 degrees C, the resistance to defect formation has now been improved to that of stoichiometric ZnSe, These results demonstrate that epitaxially grown CILs provide a means to alter ZnSe/GaAs band offsets without degrading the heterojunction's resistance to defect formation at elevated temperatures. C1 Ctr Mat Res, Berkeley, CA 94720 USA. Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. INFM, TASC, Lab Nazl, I-34012 Trieste, Italy. Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy. Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. RP Schafer, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Mailstop 7-222,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 21 TC 0 Z9 0 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUL PY 1999 VL 28 IS 7 BP 881 EP 886 DI 10.1007/s11664-999-0214-8 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 217QP UT WOS:000081510700004 ER PT J AU Aceves, SM Smith, JR Westbrook, CK Pitz, WJ AF Aceves, SM Smith, JR Westbrook, CK Pitz, WJ TI Compression ratio effect on methane HCCI combustion SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article AB We have used the HCT (hydrodynamics, chemistry, and transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, burn duration, NOx production, gross indicated efficiency, and gross IMEP of a supercharged engine (3 arm, intake pressure) with 14:1, 16:1 and 18:1 compression ratios at 1200 rpm. HCT has been modified to incorporate the effect of heat transfer and to calculate the temperature that results from mixing the recycled exhaust with the fresh mixture. This study uses a single reaction zone that varies as a function of crank angle. The ignition process is controlled by adjusting the intake equivalence ratio and the residual gas trapping (RGT). RGT is internal exhaust gas recirculation, which recycles both thermal energy and combustion product species. Adjustment of equivalence ratio and RGT is accomplished by varying the timing of the exhaust valve closure in either two-stroke or four-stroke engines. Inlet manifold temperature is held constant at 300 K. Results show that, for each compression ratio, there is a range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated efficiency above 50 percent and NOx levels below 100 ppm. HCT results are also compared with a set of recent experimental data for natural gas. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Aceves, SM (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave,L-641, Livermore, CA 94551 USA. RI aceves, salvador/G-9052-2011 OI aceves, salvador/0000-0001-5687-7256 NR 26 TC 24 Z9 25 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JUL PY 1999 VL 121 IS 3 BP 569 EP 574 DI 10.1115/1.2818510 PG 6 WC Engineering, Mechanical SC Engineering GA 220AB UT WOS:000081640500027 ER PT J AU Choi, W Camassa, R AF Choi, W Camassa, R TI Exact evolution equations for surface waves SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article; Proceedings Paper CT 12th ASCE Engineering Mechanics Conference CY MAY 17-20, 1998 CL LA JOLLA, CALIFORNIA SP ASCE ID STEEP GRAVITY-WAVES; IDEAL FLUID; WATER; DYNAMICS; DEPTH AB This paper considers surface gravity-capillary waves in an ideal fluid of finite depth and generalizes exact evolution equations for free gravity waves obtained by Dyachenko et al. to those for forced gravity-capillary waves. The model derived here describes the time evolution of the free surface and the velocity potential evaluated at the free surface under external pressure forcing. Two integro-differential equations are written explicitly in terms of these two dependent variables, and no extra step is required to close the system. These equations are solved numerically for the particular case of stationary periodic waves, and the results compared with analogous ones available in the literature. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Choi, W (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 13 TC 28 Z9 28 U1 1 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD JUL PY 1999 VL 125 IS 7 BP 756 EP 760 DI 10.1061/(ASCE)0733-9399(1999)125:7(756) PG 5 WC Engineering, Mechanical SC Engineering GA 207PA UT WOS:000080944200005 ER PT J AU Garten, CT Wullschleger, SD AF Garten, CT Wullschleger, SD TI Soil carbon inventories under a bioenergy crop (switchgrass): Measurement limitations SO JOURNAL OF ENVIRONMENTAL QUALITY LA English DT Article ID CULTIVATION; STORAGE AB Approximately 5 yr after planting, coarse root (>2 mm) carbon (C) and soil organic C (SOC) inventories (0-10 cm deep) were compared under different types of plant cover at four switchgrass (Panicum virgatum L.) production field trials in the southeastern USA. There was significantly (p less than or equal to 0.05) more coarse root C under switchgrass (Alamo variety) and forest col-er than under tall fescue (Festuca arundinacea Schreb.), corn (Zea mays L,), or native pastures of mixed grasses. Inventories of SOC under switchgrass were not significantly greater than SOC inventories under other plant covers. At some locations the statistical power associated with ANOVA of SOC inventories was low, which raised questions about whether differences in SOC could be detected statistically. A minimum detectable difference (MDD) for SOC inventories was calculated. The MDD is the smallest detectable difference between treatment means once the variation, significance level, statistical power, and sample size are specified. The analysis indicated that a difference of approximate to 50 mg SOC/cm(2) or 5 Mg SOC/ ha, which is approximate to 10 to 15% of existing SOC, could be detected with reasonable sample sizes (n = 16) and good statistical power (1 - beta = 0.90). The smallest difference in SOC inventories that can be detected, and only with exceedingly large sample sizes (n > 100), is approximate to 2 to 3% (approximate to 10 mg SOC/cm(2) or 1 Mg SOC/ha), These measurement limitations have implications for monitoring and verification of proposals to ameliorate increasing global atmospheric CO2 concentrations by sequestering C in soils. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Garten, CT (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Wullschleger, Stan/B-8297-2012 OI Wullschleger, Stan/0000-0002-9869-0446 NR 16 TC 100 Z9 102 U1 4 U2 24 PU AMER SOC AGRONOMY PI MADISON PA 677 S SEGOE RD, MADISON, WI 53711 USA SN 0047-2425 J9 J ENVIRON QUAL JI J. Environ. Qual. PD JUL-AUG PY 1999 VL 28 IS 4 BP 1359 EP 1365 PG 7 WC Environmental Sciences SC Environmental Sciences & Ecology GA 214UF UT WOS:000081345400039 ER PT J AU Doeller, JE Gaschen, BK Parrino, V Kraus, DW AF Doeller, JE Gaschen, BK Parrino, V Kraus, DW TI Chemolithoheterotrophy in a metazoan tissue: Sulfide supports cellular work in ciliated mussel gills SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE sulphide; gill; ciliary beat frequency; oxygen consumption rate; mitochondrial cytochrome; antimycin A; mussel; Geukensia demissa; Mytilus edulis; Rana pipiens ID SOLEMYA-REIDI; ARENICOLA-MARINA; OXIDATIVE-PHOSPHORYLATION; FROG PALATE; MITOCHONDRIA; TOLERANCE; DETOXIFICATION; ADAPTATIONS; STIMULATION; FREQUENCY AB Hydrogen sulfide, a common constituent of marine intertidal sediments, is both a potent toxin of aerobic cellular respiration and an electron-rich molecule used by some prokaryotic organisms as a source of energy, In ciliated gills from Geukensia demissa, a marine mussel from sulfide-rich sediments, sulfide oxidation supports cellular work, Evidence for this comes from measurements of ciliary beat frequency (f(CB)) as a measure of ATP turnover rate, the rate of gill oxygen consumption ((M) over dot (O2)) as a measure of ATP production rate, and mitochondrial cytochrome redox state as an indicator of the path of electron flow, Results from experiments performed in the presence and absence of the mitochondrial complex III inhibitor antimycin A to limit endogenous carbon substrate oxidation showed that exposure to sulfide stimulated oxygen consumption and ciliary beating, with cytochrome c being the dominant reduced species. These results, along with the resultant f(CB)/(M) over dot (O2), ratio, are qualitatively and quantitatively consistent with the hypothesis that electrons from sulfide oxidation support mitochondrial ATP production, We propose that Geukensia demissa gills use sulfide as a respiratory substrate when given the choice and thus function metabolically as facultative chemolithoheterotrophs. Similar conclusions could not be drawn for the ciliated gills from Mytilus edulis, a marine mussel from aerated habitats, or for the ciliated lungs from the phylogenetically distinct leopard frog Rana pipiens. C1 Univ Alabama, Dept Biol, Birmingham, AL 35294 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Doeller, JE (reprint author), Univ Alabama, Dept Biol, 1300 Univ Blvd, Birmingham, AL 35294 USA. NR 32 TC 21 Z9 22 U1 2 U2 5 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD JUL PY 1999 VL 202 IS 14 BP 1953 EP 1961 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 222YX UT WOS:000081813900010 ER PT J AU Jenkins, RA Counts, RW AF Jenkins, RA Counts, RW TI Personal exposure to environmental tobacco smoke: salivary cotinine, airborne nicotine, and nonsmoker misclassification SO JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY LA English DT Article DE cotinine; environmental tobacco smoke; nicotine; personal exposure ID RESPIRABLE SUSPENDED PARTICLES; SELF-REPORT; CHEMICAL-COMPOSITION; PASSIVE SMOKING; SERUM COTININE; AIR-QUALITY; WOMEN; HEALTH; POPULATION; WORKPLACE AB A Large study was conducted to assess exposure to environmental tobacco smoke (ETS) in a geographically dispersed study population using personal breathing zone air sampling and salivary cotinine levels. Approximately 100 self-reported nonsmoking subjects in each of 16 metropolitan areas were recruited for this investigation. Cumulative distributions of salivary cotinine levels for subjects in smoking and nonsmoking homes and workplaces exhibited a general trend of decreasing salivary cotinine levels with decreasing time spent in smoking environments. Median salivary cotinine levels for the four experimental cells in the study (product of smoking and nonsmoking home and workplaces) were comparable to those reported for a large national study of serum levels of cotinine (Third National Health and Nutrition Examination Survey, NHANES III), when the latter was corrected for expected differences between serum and saliva concentrations. However, the most highly exposed group in this study had a median salivary cotinine concentration approximately a factor of 2 greater than that of the comparable group in the NHANES III study. Misclassification rates, both simple (for self-reported nonsmokers) and complex (self-reported Lifetime never smokers), were near the median of those reported for other studies. Estimated misclassification rates for self-reported lifetime never-smoking females are sufficiently high (2.95% using a discrimination revel of 106 ng/ml) that, if used in the Environmental Protection Agency (EPA) risk assessment related to ETS and lung cancer, would place the lower 90% confidence interval (CI) for relative risk at nearly 1.00, i.e., no statistically significant increased risk. For the 263 most highly exposed subjects in the study whose self-reported nonsmoking status was accurate, the correlation between airborne exposure to nicotine and average salivary cotinine is so small, on an individual basis, that it makes the relationship useless for estimating exposure on a quantitative basis. When subjects are grouped according to likely categories of nicotine exposure, correlation between group median airborne nicotine exposure and salivary cotinine level increases dramatically. The comparison improves for the most highly exposed subjects, suggesting that such quantitative comparisons are useful for only those subjects who are exposed to the higher levels of ETS. However, airborne nicotine exposure for most of the subjects does not account for estimated systemic levels of nicotine, based on salivary cotinine levels. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Jenkins, RA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Mail Stop 6120,Bldg 4500S,Bethel Valley Rd,POB 20, Oak Ridge, TN 37831 USA. NR 43 TC 23 Z9 23 U1 2 U2 6 PU STOCKTON PRESS PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1053-4245 J9 J EXPO ANAL ENV EPID JI J. Expo. Anal. Environ. Epidemiol. PD JUL-AUG PY 1999 VL 9 IS 4 BP 352 EP 363 DI 10.1038/sj.jea.7500036 PG 12 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 297VM UT WOS:000086103400009 PM 10489160 ER PT J AU Groninger, JW Johnsen, KH Seiler, JR Will, RE Ellsworth, DS Maier, CA AF Groninger, JW Johnsen, KH Seiler, JR Will, RE Ellsworth, DS Maier, CA TI Elevated carbon dioxide in the atmosphere - What might it mean for loblolly pine plantation forestry? SO JOURNAL OF FORESTRY LA English DT Article ID PHOTOSYNTHETIC CAPACITY; NET PHOTOSYNTHESIS; STOMATAL CONDUCTANCE; CO2 CONCENTRATIONS; ROOT RESTRICTION; GAS-EXCHANGE; TAEDA TREES; GROWTH; SEEDLINGS; WATER AB Research with loblolly pine suggests that projected increases iii atmospheric CO2 concentration will accelerate early growth and could result in shouter rotation length, reduced time until first commercial thinning, higher optimal planting density, and possibly higher maximum stocking level in managed stands. We discuss some of the physiological processes and stand dynamics that underlie these changes, as well as silvicultural strategies that may serve to ensure sustainability of intensively managed forest systems in the face of increasing CO2 and possible climate change. C1 So Illinois Univ, Dept Forestry, Carbondale, IL 62901 USA. USDA, Forest Serv, So Res Stn, Res Triangle Pk, NC USA. Virginia Tech, Dept Forestry, Blacksburg, VA USA. Univ Georgia, Dept Forestry, Athens, GA 30602 USA. Brookhaven Natl Lab, Div Environm Biol, Upton, NY 11973 USA. RP Groninger, JW (reprint author), So Illinois Univ, Dept Forestry, Carbondale, IL 62901 USA. RI Groninger, John/A-2566-2008; Will, Rodney/G-8111-2011; OI Ellsworth, David/0000-0002-9699-2272 NR 37 TC 12 Z9 12 U1 0 U2 3 PU SOC AMER FORESTERS PI BETHESDA PA 5400 GROSVENOR LANE, BETHESDA, MD 20814 USA SN 0022-1201 J9 J FOREST JI J. For. PD JUL PY 1999 VL 97 IS 7 BP 4 EP 10 PG 7 WC Forestry SC Forestry GA 213DK UT WOS:000081256700003 ER PT J AU Yur, G Chang, TF Rahman, HU Birn, J Chao, CE AF Yur, G Chang, TF Rahman, HU Birn, J Chao, CE TI Magnetotail structures in a laboratory magnetosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Meeting on the Interrelationship Between Plasma Experiments in the Laboratory and in Space CY 1997 CL MAUI, HAWAII ID INTERPLANETARY MAGNETIC-FIELD; CURRENT SHEET; SIMULATION; SUBSTORM; REGION; PLASMA AB The structure of the magnetotail is investigated in a laboratory simulated magnetosphere. This study builds upon our previous investigation of the magnetotail [Birn et al., 1992], which was explored magnetotail through models and magnetic field measurements in the simulated magnetosphere. In this paper the magnetic field measurements are complemented by measurements of ion and electron fluxes, plasma temperature and high-resolution optical images. Plasma fluxes are measured with a double-sided Faraday cup that measures the ion and electron fluxes of counterstreaming plasma simultaneously in both directions. The overall magnetotail structure is examined with high-resolution imaging using a gated optical imager and applying digital enhancement to the magnetotail region. These images confirm the structures inferred earlier from the magnetic field measurements, a Y-type magnetic neutral line for northward interplanetary magnetic field, and the expected X-type structure for southward IMF. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Riverside, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. Natl Cent Univ, Inst Space Sci, Chungli 320, Taiwan. RP Yur, G (reprint author), Ind Technol Res Inst, Hsinchu, Taiwan. NR 22 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1999 VL 104 IS A7 BP 14517 EP 14528 DI 10.1029/98JA02193 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211WW UT WOS:000081185700009 ER PT J AU Yamada, M AF Yamada, M TI Review of controlled laboratory experiments on physics of magnetic reconnection SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Meeting on the Interrelationship Between Plasma Experiments in the Laboratory and in Space CY 1997 CL MAUI, HAWAII ID CURRENT SHEET; PLASMA; FIELD; LAYERS; ASTROPHYSICS; REGIONS AB We review results from the most recent experiments in the past 2 decades in which magnetic reconnection has been generated and studied in controlled laboratory settings. As a whole, research on the fundamental physics of the reconnection process and its hydromagnetic consequences has been largely theoretical. Laboratory experiments are crucial for understanding the fundamental physics of magnetic reconnection since they can provide well-correlated plasma parameters at multiple plasma locations simultaneously, while satellites can only provide information from a single location at a given time in a space plasma. Thanks to the significant progress of data acquisition technology, the detailed magnetic field structures of the reconnection regions were measured and plasma acceleration and strong ion heating were identified. Extensive data have been accumulated in the electron MHD plasma regimes [in which electrons are magnetized] with relatively low Lundquist number of S = 1 - 10 as well as in MHD plasmas with S = 100 - 1000. This article puts a special focus on the most recent plasma merging experiments in the MHD regime since they are new and have been published in the past several years. Two distinctly different shapes of diffusion regions were identified both in the electron MHD plasma regime [Stenzel and Gekelman, 1983] and in the MHD plasmas in MRX [Yamada et al., 1997b]. The familiar two-dimensional (2-D) feature, a double-Y-shaped diffusion region, was identified when there is no or very little axial magnetic field (third vector component). In cohelicity merging with a sizable third field component, an O-shaped diffusion region appears and the reconnection rate decreases substantially; this is attributed to the axial field pressure and the incompressibility of the plasma. Another important achievement is the experimental verification of a generalized Sweet-Parker model [Ji et al., 1998], In this recent work it is found that the observed reconnection rate can be explained by a generalized Sweet-Parker model, which incorporates compressibility, downstream pressure and the effective resistivity. The latter is often enhanced over its classical values in the collisionless limit. A significant implication of this result is that the generalized Sweet-Parker model is valid in certain 2-D reconnection cases with axisymmetric geometry. In MI-ID plasmas, the thickness of this thin current layer is found to be of the order of the ion gyroradius and the ion skin depth as well. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Yamada, M (reprint author), Princeton Univ, Plasma Phys Lab, James Forrestal Campus,POB 451, Princeton, NJ 08543 USA. RI Yamada, Masaaki/D-7824-2015 OI Yamada, Masaaki/0000-0003-4996-1649 NR 50 TC 26 Z9 26 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1999 VL 104 IS A7 BP 14529 EP 14541 DI 10.1029/1998JA900169 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211WW UT WOS:000081185700010 ER PT J AU Lawrence, DJ Thomsen, MF Borovsky, JE McComas, DJ AF Lawrence, DJ Thomsen, MF Borovsky, JE McComas, DJ TI Measurements of early and late time plasmasphere refilling as observed from geosynchronous orbit SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-DENSITY; MODEL; ANALYZER; GEOS-2 AB Measurements of the cold ion density at geosynchronous orbit obtained by Los Alamos magnetospheric plasma analyzers over the course of 7 years are used to estimate the rate of plasmaspheric refilling at early times in the refilling process (less than or equal to 24 hours) and at late times (up to several days during intervals of prolonged geomagnetic quiet). While the measured refilling rates are highly variable, we find that plasmasphere refilling at geosynchronous orbit occurs as a two-step process: for early times the refilling rate is similar to 0.6-12 cm(-3) d(-1), while for later times the refilling rate rises up to 10-50 cm(-3) d(-1). These results are consistent with a model of plasmasphere refilling which uses Coulomb collisions as a dominant trapping mechanism [see Wilson et al. 1992]. C1 Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87544 USA. RP Lawrence, DJ (reprint author), Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87544 USA. RI Lawrence, David/E-7463-2015 OI Lawrence, David/0000-0002-7696-6667 NR 22 TC 47 Z9 47 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1999 VL 104 IS A7 BP 14691 EP 14704 DI 10.1029/1998JA900087 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211WW UT WOS:000081185700023 ER PT J AU Jorgensen, AM Spence, HE Hughes, TJ McDiarmid, D AF Jorgensen, AM Spence, HE Hughes, TJ McDiarmid, D TI A study of omega bands and Ps6 pulsations on the ground, at low altitude and at geostationary orbit SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FIELD AB We investigate the electrodynamic coupling between auroral omega bands and the inner magnetosphere, The goal of this study is to determine the features to which omega bands map in the magnetosphere. To establish the auroral-magnetosphere connection, we appeal to the case study analysis of the data rich event of September 26, 1989. At 6 magnetic local time (MLT), two trains of Ps6 pulsations (ground magnetic signatures of omega bands) were observed to drift over the Canadian Auroral Network For the OPEN Program Unified Study (CANOPUS) chain, At the same time periodic ionospheric flow patterns moved through the collocated Bistatic Auroral Radar System (BARS) field of view. Similar coincident magnetic variations were observed by GOES 6, GOES 7 and SCATHA, all of which had magnetic foot points near the CANOPUS/BARS stations. SCATHA, which was located at 6 MLT, 0.5 R-E earthward of GOES 7 observed the 10 min period pulsations, whereas GOES 7 did not. In addition, DMSP F6 and F8 were over-flying the region and observed characteristic precipitation and flow signatures, From this fortunate constellation of ground and space observations, we conclude that auroral omega bands are the electrodynamic signature of a corrugated current sheet (or some similar spatially localized magnetic structure) in the near-Earth geostationary magnetosphere. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Ottawa, ON K1A 0R6, Canada. RP Jorgensen, AM (reprint author), Univ Calif Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. RI Spence, Harlan/A-1942-2011; OI Spence, Harlan/0000-0002-2526-2205 NR 11 TC 14 Z9 14 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1999 VL 104 IS A7 BP 14705 EP 14715 DI 10.1029/1998JA900100 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211WW UT WOS:000081185700024 ER PT J AU Meyer, PD Gee, GW AF Meyer, PD Gee, GW TI Flux-based estimation of field capacity SO JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING LA English DT Article ID NEURAL NETWORKS; WATER-RETENTION; SOILS AB Field capacity has been defined as the water content at which the drainage flux from a soil ceases, or becomes negligible. Field capacity is most commonly estimated as the water content at a pressure head of 1/3 bar, which ignores its flux-based nature. A number of authors have proposed estimating field capacity as the water content at a given (negligible) flux, assuming unit gradient conditions. This flux-based method of estimating field capacity is discussed and the differences between this method and the more common pressure-based method are illustrated. The drainage flux considered to be negligible will depend on the particular application; values between 10(-6) and 10(-8) cm/s were considered here. The observed differences in field capacity resulting from the negligible flux range considered produce significant differences in the available water capacity. These differences directly impact the calculated drainage. The effect of available water capacity on the water budget for waste disposal facility covers at an arid and humid site was illustrated using the HELP code. At the arid site, drainage decreased by a factor of 4 (from 25 to 6 mm/year) as the available water capacity increased from 0.101 to 0.199. At the;humid site, drainage decreased from 190 to 173 mm/year over the same range of available water capacity. Finally, a simple procedure for the determination of an appropriate value for the negligible flux is discussed. Analysis of data from a lysimeter at Coshocton, Ohio, indicated that field capacity for the lysimeter soils was associated with a negligible drainage flux of about 3 x 10(-7) cm/s. C1 Pacific NW Nat Lab, Portland, OR 97204 USA. Pacific NW Nat Lab, Richland, WA 99352 USA. RP Meyer, PD (reprint author), Pacific NW Nat Lab, 620 SW 5th Ave,810, Portland, OR 97204 USA. OI Meyer, Philip/0000-0002-8714-4693 NR 15 TC 22 Z9 23 U1 1 U2 8 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 1090-0241 J9 J GEOTECH GEOENVIRON JI J. Geotech. Geoenviron. Eng. PD JUL PY 1999 VL 125 IS 7 BP 595 EP 599 DI 10.1061/(ASCE)1090-0241(1999)125:7(595) PG 5 WC Engineering, Geological; Geosciences, Multidisciplinary SC Engineering; Geology GA 208TF UT WOS:000081007200006 ER PT J AU Molloy, DP Vinikour, WS Anderson, RV AF Molloy, DP Vinikour, WS Anderson, RV TI New north American records of aquatic insects as paratenic hosts of Pheromermis (Nematoda : Mermithidae) SO JOURNAL OF INVERTEBRATE PATHOLOGY LA English DT Article DE Hesperophylax designatus; Lepidostoma liba; Glossosoma intermedium; Diplectrona modesta; Clioperla clio; Amphinemura delosa; Pheromermis vesparum; Pheromermis pachysoma; prevalence and intensity of infection AB Several species of aquatic insects in Trout Park Nature Preserve (Elgin, IL) were observed to have small, black spots (<0.1 mm diameter) visible within their bodies. Microscopic examination revealed these spots to be coiled juveniles of a mermithid (Nematoda: Mermithidae). Based on host habitat (seepage areas and rivulets), host species (aquatic insects), and size (mean diameter of coiled juveniles = 79 mu m), it is likely that these mermithids were in the genus Pheromermis. Since adult mermithids were not found, species determination was not feasible, and the possibility of a new species cannot be ruled out. Pheromermis pachysoma and Pheromermis vesparum, however, are two species known to use aquatic insects as paratenic (i.e., transport) hosts in order to reach their definitive hosts, vespid wasps. Wasp larvae are infected by consuming the flesh of adult aquatic insects that contain the coiled juveniles of these Pheromermis spp. Of the 19 macroinvertebrate species examined in this study, Pheromermis juveniles were found in 4 caddisfly species (Hesperophylax designatus, Lepidostoma liba, Glossosoma intermedium, and Diplectrona modesta) and in 2 stonefly species (Clioperla clio and Amphinemura delosa). In addition to all 6 insect species being new host records for Pheromermis infection, this also represents the first report of nematode infection in stoneflies within the Western Hemisphere and of a Pheromermis sp. in Illinois. Among trophic groups, insect detritivores have been frequently recorded infected with coiled Pheromermis juveniles because of their direct consumption of eggs, and we also observed this for detritivores in our investigation (e.g., L. liba and A. delosa). Because C. clio was intensively infected, however, our study also provided evidence that predatory insects can be paratenic hosts. Coiled juveniles were typically present in muscle and fat body and present in almost all body regions. Not every infected paratenic host had external signs of infection; thus, dissections are required for accurate determination of infection prevalence and intensity. Our findings, in conjunction with those made in previous studies, indicate that a wide variety of aquatic insects may be used as paratenic hosts by Pheromermis. Because of their small size, it is highly likely that coiled juveniles are either overlooked or mistaken for melanized integumental wounds during field studies of aquatic insects. A more careful inspection for these coiled juveniles in aquatic insects, especially detritivores and their predators in seepage areas, would probably reveal that Pheromermis is far more common than presently documented. (C) 1999 Academic Press. C1 New York State Museum, Biol Survey, Cultural Educ Ctr, Albany, NY 12230 USA. Argonne Natl Lab, Environm Assessment Div, Argonne, IL 60439 USA. Western Illinois Univ, Dept Sci Biol, Macomb, IL 61455 USA. RP Molloy, DP (reprint author), New York State Museum, Biol Survey, Cultural Educ Ctr, Albany, NY 12230 USA. NR 14 TC 4 Z9 4 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2011 J9 J INVERTEBR PATHOL JI J. Invertebr. Pathol. PD JUL PY 1999 VL 74 IS 1 BP 89 EP 95 DI 10.1006/jipa.1999.4860 PG 7 WC Zoology SC Zoology GA 216AA UT WOS:000081417100010 ER PT J AU Forte, TM Oda, MN Knoff, L Frei, B Suh, J Harmony, JAK Stuart, WD Rubin, EM Ng, DS AF Forte, TM Oda, MN Knoff, L Frei, B Suh, J Harmony, JAK Stuart, WD Rubin, EM Ng, DS TI Targeted disruption of the murine lecithin : cholesterol acyltransferase gene is associated with reductions in plasma paraoxonase and platelet-activating factor acetylhydrolase activities but not in apolipoprotein J concentration SO JOURNAL OF LIPID RESEARCH LA English DT Article DE LCAT deficiency; nascent HDL; lipid hydroperoxides; apoA-I; antioxidative enzymes; fast protein liquid chromatography ID LOW-DENSITY-LIPOPROTEIN; DEPENDENT DIABETES-MELLITUS; HUMAN SERUM PARAOXONASE; EXPRESSION; DEFICIENCY; PROTEIN; ENZYMES; ATHEROSCLEROSIS; HYDROPEROXIDES; PURIFICATION AB Lecithin:cholesteryl acyltransferase (LCAT) deficiency resulting from targeted disruption of the Leaf gene in the mouse is associated with dramatic decreases in HDL concentration and the accumulation of nascent HDL in the plasma. We examined whether LCAT deficiency in mice is associated with a concomitant decrease in two antioxidative enzymes, paraoxonase (PON) and platelet-activating factor acetylhydrolase (PAF-AH), In control Lcat(+/+) mice both these enzymes are transported on HDL, Compared to Lcat (+/+) mice, HDL-cholesterol is reduced 94% and apoA-I, 90%, in Lcat (-/-) mice; this reduction in HDL is paralleled by a 71% decrease in PAF-AH activity and in a 58% decrease in PON activity. Apolipoprotein J (apoJ) levels, rather than being decreased, were significantly (P = 0.01) higher (36%) in Lent (-/-) than in Lcat (+/+) mice, and the apo J/PON ratio was 3-fold greater in Lcat (-/-) than in Lcat (+/+) animals. Even though apolipoprotein A-I (apoA-I) concentration and PON activity were drastically reduced, there was no reduction in apoA-I and PON liver mRNA levels suggesting that post-transcriptional events are responsible for the reduction of plasma PON and apoA-I levels. Fast protein liquid chromatography (FPLC) revealed that in Leaf (+/+) mice both PON and PAF-AH activity is associated with large, apoA-I-containing HDL particles (9.7 nn by non-denaturing gradient gel electrophoresis) while in Lcat (-/-) mice both enzymes are associated with small 8.2 nm particies. We conclude that the concomitant reduction in HDL and apoA-I concentrations and PON and PAF-AH activities is best explained by rapid clearance of the small HDL particles found in LCAT deficiency. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94729 USA. Oregon State Univ, Linus Pauling Inst, Corvallis, OR 97331 USA. Univ Cincinnati, Coll Med, Dept Pharmacol & Cell Biophys, Cincinnati, OH 45267 USA. RP Forte, TM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94729 USA. FU NHLBI NIH HHS [HL 18574, HL 27333]; PHS HHS [NIH 56170] NR 44 TC 35 Z9 36 U1 0 U2 1 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD JUL PY 1999 VL 40 IS 7 BP 1276 EP 1283 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 212CN UT WOS:000081198900011 PM 10393212 ER PT J AU Klemme, BJ Adriaans, MJ Day, PK Sergatskov, DA Aselage, TL Duncan, RV AF Klemme, BJ Adriaans, MJ Day, PK Sergatskov, DA Aselage, TL Duncan, RV TI PdMn and PdFe: New materials for temperature measurement near 2 K SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article ID CRITICAL-DYNAMICS; GIANT-MOMENT; ALLOYS; FERROMAGNETISM; PALLADIUM; MICROGRAVITY; THERMOMETER; BEHAVIOR; RANGE; IRON AB Interest in the critical dynamics of superfluid He-4 in microgravity conditions has motivated the development of new high resolution thermometry technology for use in space experiments near 2 K. We have developed a magnetic thermometer using dilute magnetic alloys of Mn or Fe dissolved in a pure Pd matrix, similar to previous thermometers used at ultra-low temperatures. These metallic thermometers are easy to fabricate, chemically inert, and can have a low thermal resistance to the stage to be measured Also, the Curie temperature can be varied by changing the concentration of Fe of Mn, making them available for use in a wide temperature range. The derivative of the magnetic susceptibility was measured for PdMn and PdFe between 1.5 K and 4 K using a SQUID magnetometer. These measurements, as well as preliminary noise and drift measurements, show them to have sub-nK resolution with a drift of less than 10(-13) K/s. C1 Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Klemme, BJ (reprint author), Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. NR 22 TC 32 Z9 32 U1 1 U2 8 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD JUL PY 1999 VL 116 IS 1-2 BP 133 EP 146 DI 10.1023/A:1021883011172 PG 14 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 216JF UT WOS:000081438400007 ER PT J AU Boyd, JK AF Boyd, JK TI Electron spin transition solution applicable to an ensemble of isolated electrons SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE electron spin resonance; ESR; electron spin transition; analytic electron spin solution; fermion spin transition; rotating wave approximation ID ROTATING-WAVE APPROXIMATION; JAYNES-CUMMINGS MODEL; BLOCH-SIEGERT SHIFT; SPECTROSCOPY; ATOM AB An electron spin aligned with a static magnetic field changes its orientation when subjected to a time-varying magnetic field which is directed perpendicular to the static magnetic field. This well-known phenomenon is readily calculated when the time-varying magnetic field is circularly polarized; however, the evolution of the spin-state wavefunctions becomes much more difficult to calculate when the time-varying magnetic field is linearly polarized. For linear polarization and isolated spins, an analytic solution has been derived for the dynamical spin-state wavefunctions. Part of the solution procedure relies on an expansion using a small parameter, which is the ratio of the amplitude of the time-varying magnetic field to the static magnetic field. To verify the validity of the expansion technique, a numerical solution of the basic equations is compared to the analytic solution. Results are found to agree to better than 10% for exact resonance and better than 5% in general. (C) 1999 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Boyd, JK (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-095, Livermore, CA 94551 USA. NR 30 TC 2 Z9 2 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1090-7807 J9 J MAGN RESON JI J. Magn. Reson. PD JUL PY 1999 VL 139 IS 1 BP 109 EP 125 DI 10.1006/jmre.1999.1770 PG 17 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 217BX UT WOS:000081480600013 PM 10388590 ER PT J AU Fisher, IR Islam, Z Canfield, PC AF Fisher, IR Islam, Z Canfield, PC TI Magnetic and transport properties of single-crystal R2Cu2In (R = Gd-Tm, Lu) SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE rare-earth compounds; magnetic-phase transitions; magnetic anisotropy ID T=NI; PD; CE2T2IN; CU AB Magnetic and transport properties of the heavy-rare-earth-containing series of compounds R2Cu2In (R = Gd-Lu, excepting Yb) are presented for the first time. Measurements were made using single-crystal samples grown via a self-flux technique. The magnetic rare-earth compounds all order ferromagnetically. Ordering temperatures vary between 26.7 (R = Ho) and 85.5 K (R = Gd), but strong crystal electric field anisotropies result in T-C values that do not scale with the de Gennes factor of the rare earths. The compound Dy2Cu2In shows clear evidence of a second phase transition at a lower temperature than T-C = 45.5 K to an antiferromagnetic ground state at T-N = 22.0 K. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. RP Fisher, IR (reprint author), Iowa State Univ, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 6 TC 22 Z9 22 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUL PY 1999 VL 202 IS 1 BP 1 EP 10 DI 10.1016/S0304-8853(99)00383-2 PG 10 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 212MW UT WOS:000081221300001 ER PT J AU Isbell, DT Gusev, AI Taranenko, NI Chen, CH Hercules, DM AF Isbell, DT Gusev, AI Taranenko, NI Chen, CH Hercules, DM TI Separation and detection of carcinogen-adducted oligonucleotides SO JOURNAL OF MASS SPECTROMETRY LA English DT Letter ID THIN-LAYER CHROMATOGRAPHY; ASSISTED LASER DESORPTION/IONIZATION; FLIGHT MASS-SPECTROMETRY; DESORPTION IONIZATION; DNA-ADDUCTS; MATRIX; RESOLUTION C1 Vanderbilt Univ, Dept Chem, Nashville, TN 37235 USA. Rohm & Haas Co, Res Labs, Spring House, PA 19477 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Isbell, DT (reprint author), Vanderbilt Univ, Dept Chem, Box 1583, Nashville, TN 37235 USA. FU NIEHS NIH HHS [ES00267] NR 19 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1076-5174 J9 J MASS SPECTROM JI J. Mass Spectrom. PD JUL PY 1999 VL 34 IS 7 BP 774 EP 776 PG 3 WC Biophysics; Chemistry, Organic; Spectroscopy SC Biophysics; Chemistry; Spectroscopy GA 218NA UT WOS:000081557600009 PM 10407363 ER PT J AU Kriese, MD Gerberich, WW Moody, NR AF Kriese, MD Gerberich, WW Moody, NR TI Quantitative adhesion measures of multilayer films: Part I. Indentation mechanics SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID STRESSED THIN-FILMS; BLISTER TEST; FRACTURE ENERGY; BIMATERIAL INTERFACES; RESIDUAL-STRESSES; EDGE CRACKING; TOUGHNESS; DECOHESION; NANOINDENTATION; DELAMINATION AB The mechanics for calculating the quantitative driving force of indentation-induced delamination of thin-film multilayers is presented. The solution is based on the mechanics developed by Marshall and Evans [D.B. Marshall and A.G. Evans, J. Appl. Phys. 56, 2632 (1984).] and extended to the general case of a multilayer by use of standard bending and thin-plate analyses. Presented and discussed are the specific solutions for the bilayer case that show that in the limit of zero thickness of either layer, the solution converges to the single-layer case. In the range of finite thickness, the presence of the superlayer increases the driving force relative to that possible for the original film alone and can be optimized to the experimental situation by proper choice of thickness, elastic constants, and residual stress. The companion paper "Quantitative adhesion measures of multilayer films: Part II. Indentation of W/Cu, W/W, Cr/W" discusses experimental results with copper, tungsten, and chromium thin films. C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Kriese, MD (reprint author), Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. NR 43 TC 112 Z9 116 U1 0 U2 33 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1999 VL 14 IS 7 BP 3007 EP 3018 DI 10.1557/JMR.1999.0404 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 235PF UT WOS:000082550700045 ER PT J AU Kriese, MD Gerberich, WW Moody, NR AF Kriese, MD Gerberich, WW Moody, NR TI Quantitative adhesion measures of multilayer films: Part II. Indentation of W/Cu, W/W, Cr/W SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MICROWEDGE INDENTATION; BIMATERIAL INTERFACES; THIN-FILMS; FINE LINE; TOUGHNESS; MECHANICS; ENERGY; DELAMINATION; DIELECTRICS; SPECIMENS AB Sputtered copper and tungsten thin films both with and without tungsten and chromium superlayers were tested by using nanoindentation probing to initiate and drive delamination. The adhesion energies of the films were calculated from the induced delaminations using the analysis.presented in "Quantitative adhesion measures of multilayer films: Part I. Indentation mechanics." Copper films ranging in thickness from 150 to 1500 nm in the as-sputtered condition had measured adhesion energies ranging from 0.2 to 2 J/m(2), commensurate with the thermodynamic work of adhesion. Tungsten films ranging in thickness from 500 to 1000 nm in the as-sputtered condition had measured adhesion energies ranging from 5 to 15 J/m(2). The superlayer was shown to induce radial cracking when under residual tension, resulting in underestimation of the adhesion energy when the film was well adhered. Under conditions of weak adherence or residual compression, the superlayer provided an excellent means to induce a delamination and allowed an accurate and reasonably precise quantitative measure of thin film adhesion. C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Kriese, MD (reprint author), Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. NR 30 TC 70 Z9 70 U1 0 U2 17 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1999 VL 14 IS 7 BP 3019 EP 3026 DI 10.1557/JMR.1999.0405 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 235PF UT WOS:000082550700046 ER PT J AU Xu, HW Heaney, PJ Yates, DM Von Dreele, RB Bourke, MA AF Xu, HW Heaney, PJ Yates, DM Von Dreele, RB Bourke, MA TI Structural mechanisms underlying near-zero thermal expansion in beta-eucryptite: A combined synchrotron x-ray and neutron Rietveld analysis SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID PHASE-TRANSITIONS; DIFFRACTION; QUARTZ; MINERALS; SILICA AB The structures of ordered and disordered beta-eucryptite have been determined from Rietveld analysis of powder synchrotron x-ray and neutron diffraction data over a temperature range of 20 to 873 K. On heating, both materials show an expansion within the (001) plane and a contraction along the c axis. However, the anisotropic character of the thermal behavior of ordered beta-eucryptite is much more pronounced than that of the disordered compound; the linear expansion coefficients of the ordered and disordered phases are alpha(a), = 7.26 x 10(-6) K-1; ex, = -16.35 x 10(-6) K-1, and cr, -3.82 x 10-6 K-1, respectively. The thermal behavior of 5.98 x 10-6 K-1: beta-eucryptite can be attributed to three interdependent processes that all cause an increase in a but a decrease in c with increasing temperature: (i) Si/Al tetrahedral deformation, (ii) Li positional disordering, and (iii) tetrahedral tilting. Because disordered beta-eucryptite does not exhibit tetrahedral tilting, the absolute values of its axial thermal coefficients are smaller than those for the ordered sample. At low temperatures, both ordered and disordered beta-eucryptite exhibit a continuous expansion parallel to the c axis with decreasing temperature, whereas a remains approximately unchanged. Our difference Fourier synthesis reveals localization of Li ions below room temperature, and we suggest that repulsion between Li and Al/Si inhibits contraction along the a axes. C1 Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. Univ Calif Los Alamos Natl Lab, Manuel Lujan Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Xu, HW (reprint author), Univ Calif Davis, Thermochem Facil, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. NR 43 TC 45 Z9 46 U1 0 U2 9 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1999 VL 14 IS 7 BP 3138 EP 3151 DI 10.1557/JMR.1999.0421 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 235PF UT WOS:000082550700062 ER PT J AU McGibbon, AJ Pennycook, SJ Jesson, DE AF McGibbon, AJ Pennycook, SJ Jesson, DE TI Crystal structure retrieval by maximum entropy analysis of atomic resolution incoherent images SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE atomic resolution; crystal structure retrieval; incoherent imaging; maximum entropy; STEM; Z-contrast imaging ID SCATTERED ELECTRONS; RECONSTRUCTION; CDTE/GAAS(001); DECONVOLUTION; ENHANCEMENT; MICROSCOPY; STEM AB In this paper, we discuss the application of the maximum entropy method to atomic resolution Z-contrast images acquired in a scanning transmission electron microscope, Z-contrast is an incoherent imaging technique, and can be described as a convolution between an object function (the real-space map of the columnar scattering cross-section to high angles) and a point spread function (the effective electron probe). As such, we show that the technique is ideally suited to maximum entropy analysis which can, given an electron probe distribution, retrieve the 'most likely' Z-contrast object function. Using both simulated and experimentally acquired data, we explore the capabilities of maximum entropy analysis when applied to atomic resolution Z-contrast images, drawing conclusions on both the range of applicability of the technique and the nature of the retrieved crystal structures. Ultimately, we show the way in which the combination of Z-contrast imaging with maximum entropy analysis can be used to yield important information on unexpected atomic structures. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Pennycook, SJ (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. OI Jesson, David/0000-0003-0897-1445 NR 26 TC 24 Z9 24 U1 0 U2 5 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD JUL PY 1999 VL 195 BP 44 EP 57 PN 1 PG 14 WC Microscopy SC Microscopy GA 220DL UT WOS:000081649200007 ER PT J AU Latrous, H Oliver, J AF Latrous, H Oliver, J TI Self-diffusion coefficients and structure of the trivalent transplutonium ion berkelium in aqueous solution SO JOURNAL OF MOLECULAR LIQUIDS LA English DT Article ID HYDRATED RADII; ACTINIDE IONS; 25-DEGREES-C; GD-153(III); LANTHANIDE AB Self-diffusion coefficients D of the trivalent aquo ion Bk3+ have been determined in aqueous Nd(ClO4)(3)-HClO4 solutions (pH 2.5) at 25 degrees C by the open end capillary method (O.E.C.M.). The variation of D versus the square root of the concentration of inactive solution is not linear in the studied range of concentration. The limiting value Do at zero ionic strength is 5.95 * 10(-6) cm(2)s(-1). The graph D = f(root C) for Bk3+ ion can be compared to those of Am-241(3+) and Eu-152(3+) Obtained under the same conditions. Moreover, it may be argued that the Bk3+, Am3+ and Eu3+ aqueous ions in solution have the same hydration as other 5f and 4f tripositive ions in the absence of hydrolysis, complexing or ion pairing at pH 2.5. A semi-quantitative extension of the Debye-Onsager limiting law available in the range of concentrations up to 1M is proposed. The present study contributes to show the analogy of solvation structure of actinides ions in aqueous solution at pH 2.5 with that of the lanthanides trivalent ions as a help for predicting their transport properties, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fac Sci Tunis, Tunis 1060, Tunisia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Latrous, H (reprint author), Fac Sci Tunis, Tunis 1060, Tunisia. NR 16 TC 11 Z9 11 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7322 J9 J MOL LIQ JI J. Mol. Liq. PD JUL PY 1999 VL 81 IS 2 BP 115 EP 121 DI 10.1016/S0167-7322(99)00060-4 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 216JY UT WOS:000081440000003 ER PT J AU Sever, DM Ryan, TJ AF Sever, DM Ryan, TJ TI Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea): Part I. Evidence for oviducal sperm storage SO JOURNAL OF MORPHOLOGY LA English DT Article DE Reptilia; Serpentes; Seminatrix pygaea; ultrastructure; oviduct; sperm ID THAMNOPHIS-SIRTALIS-PARIETALIS; MULTIPLE PATERNITY; GARTER SNAKE; INSEMINATION; SELECTION; TRANSPORT; REPTILES; CYCLES AB Oviducal sperm storage in the viviparous (lecithotrophic) colubrid snake Seminatrix pygaea was studied by light and electron microscopy. Out of 17 adult snakes examined from May-October, sperm were found in the oviducts of only two specimens. In a preovulatory female sacrificed 14 May, sperm were found in the oviducal lumen and sperm storage tubules (SSTs) of the posterior infundibulum. In a nonvitellogenic female sacrificed 9 June, sperm were found in the lumen and glands of the posterior uterus and anterior vagina, indicating a recent mating. The glands in the posterior infundibulum and vagina were simple or compound tubular, whereas glands in the uterus always were simple tubular. The epithelium of the sperm storage glands was not modified from that lining the rest of the oviduct. The cuboidal or columnar epithelium consisted of alternating ciliated and secretory areas. The secretory product released into the lumen by a merocrine process contained mucoprotein. Lipid droplets also were numerous in the epithelium. Portions of sperm sometimes were embedded in the apical cytoplasm or in secretory material. A carrier matrix containing a mucoid substance, desquamated epithelium, lipids, membranous structures, and possibly phagocytes was found around sperm in the posterior uterus. J. Morphol. 241:1-18, 1999. (C) 1999 Wiley-Liss, Inc. C1 St Marys Coll, Dept Biol, Notre Dame, IN 46556 USA. Univ Missouri, Div Biol Sci, Columbia, MO 65211 USA. Savannah River Ecol Lab, Aiken, SC USA. RP Sever, DM (reprint author), St Marys Coll, Dept Biol, Notre Dame, IN 46556 USA. NR 40 TC 31 Z9 33 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0362-2525 J9 J MORPHOL JI J. Morphol. PD JUL PY 1999 VL 241 IS 1 BP 1 EP 18 PG 18 WC Anatomy & Morphology SC Anatomy & Morphology GA 212KA UT WOS:000081214800001 ER PT J AU Paddison, SJ Pratt, LR Zawodzinski, TA AF Paddison, SJ Pratt, LR Zawodzinski, TA TI Conformations of perfluoroether sulfonic acid side chains for the modeling of Nafion (R) SO JOURNAL OF NEW MATERIALS FOR ELECTROCHEMICAL SYSTEMS LA English DT Article DE modeling; Nafion (R); electronic structure; calculations; side chains; conformations; equilibrium geometries; energy barrier ID ION-EXCHANGE MEMBRANES; POLYMER-FILMS; TRANSPORT; WATER; IONOMERS; ELECTRON; MORPHOLOGY; RESONANCE; DIFFUSION; SYSTEM AB Optimized geometries for the acid CF3OCF2CF(CF3)O(CF2)(2)SO3H and the acid chain with backbone attachment CF(CF2CF3)(2)- OCF2CF(CF3)OCF2CF2SO3H were determined with electronic structure techniques exclusive of hydration effects. The minimum energy structures are folded with the two other oxygens in a gauche conformation. Rotation about the outermost ether group provides natural transition path to the partial unfolding of the side chain. The potential energy surface for this this rotation was determined and the results showed that the staggered fluorine conformation of the head group is unchanged with rotation. This rotation produced conformations approximately 40% longer (8.5 Angstrom)and about 3.5 kcal/mol higher in energy after surmounting a barrier of about 4.6 kcal/mol. Additional searching for stretched conformations of the side chain led to the discovery of an even longer (9.8 Angstrom) minimum energy conformation that was entirely unfolded with the ether oxygens located trans relative to one other. This unfolded conformation is essentially isoenergetic (+0.1 kcal/mol) with the (folded) minimum energy conformation. The existence of a small number of well-defined "short" and "long" side chain conformations, with substantially similar head-group chemistry, suggests the speculative view that hydration-dependent equilibria between these conformations should be a significant feature in physical models of the function of Nafion(R). Equilibrium geometries were also obtained for both the folded and the unfolded acid side chains, each with an associated single water molecule. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. EM paddison@lanl.gov RI Pratt, Lawrence/H-7955-2012; Paddison, Stephen/B-2935-2014 OI Pratt, Lawrence/0000-0003-2351-7451; NR 50 TC 47 Z9 47 U1 0 U2 6 PU ECOLE POLYTECHNIQUE MONTREAL PI MONTREAL PA C P 6079, SUCC CENTRE-VILLE, MONTREAL, PQ H3C 3A7, CANADA SN 1480-2422 J9 J NEW MAT ELECTR SYS JI J. New Mat.Electrochem. Syst. PD JUL PY 1999 VL 2 IS 3 BP 183 EP 188 PG 6 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 283NF UT WOS:000085281100006 ER PT J AU Chen, A Corrales, LR AF Chen, A Corrales, LR TI A semiempirical simulation methodology: atomistic and ionic dissociation of silica SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; COVALENTLY BONDED MATERIALS; VITREOUS SILICA; ABINITIO CALCULATIONS; POTENTIAL MODELS; FORCE-FIELDS; AB-INITIO; SIO2; PRESSURE; LIQUID AB Modeling defects, surfaces and interfaces of silica is complicated by the presence of charged and uncharged states of the atoms, and the existence of local nonstoichiometric structure. The changes in the local molecular environments associated with defects and surfaces are a consequence of changes in the electronic structure away from the bulk values. The ability to capture the electronic structure changes in simulations is highly desirable to study defects and surfaces. Moreover, the properties and problems of interest also require the use of large scale simulations. Hence, a semiempirical methodology is introduced that contains these desirable properties. The model approach is described and results using the model in the absence of long range interactions are presented. The motivation to ignore Coulombic interactions is driven by the desire to understand the model's ability to describe the bonding interactions and to what degree it captures any of the medium and long range order. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Corrales, LR (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999,K1-96, Richland, WA 99352 USA. NR 55 TC 4 Z9 4 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUL PY 1999 VL 249 IS 2-3 BP 81 EP 98 DI 10.1016/S0022-3093(99)00331-2 PG 18 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 221CG UT WOS:000081706000001 ER PT J AU Gibson, JK Haire, RG Ogawa, T AF Gibson, JK Haire, RG Ogawa, T TI Semi-empirical models of actinide alloying SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID PHASE-DIAGRAM; BINARY ALLOY; NEPTUNIUM; ELECTRONEGATIVITY; CONFIGURATIONS; BEHAVIOR; SYSTEMS; METALS; NP; AM AB Alloys of Np have been studied less than those of the neighboring elements, U and Pu; the higher actinides have received even less attention. Recent interest in Np-237, Am-241 and other actinide isotopes as significant, long-lived and highly radiotoxic nuclear waste components, and particularly the roles of metallic materials in new handling/separations and remediation technologies, demands that this paucity of information concerning alloy behaviors be addressed. An additional interest in these materials arises from the possibility of revealing fundamental properties and bonding interactions, which would further characterize the unique electronic structures (e.g., Sf electrons) of the actinide elements. The small empirical knowledge basis presently available for understanding and modeling the alloying behavior of Np is summarized here, with emphasis on our recent results for the Np-Am, Np-Zr and Np-Fe phase diagrams. In view of the limited experimental data base for neptunium and the transplutonium metals, the value of semi-empirical intermetallic bonding models for predicting actinide alloy thermodynamics is evaluated. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Japan Atom Energy Res Inst, Tokai, Ibaraki 31911, Japan. RP Gibson, JK (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 45 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD JUL PY 1999 VL 273 IS 2 BP 139 EP 145 DI 10.1016/S0022-3115(99)00038-0 PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 205GH UT WOS:000080812600003 ER PT J AU Klueh, RL Alexander, DJ Rieth, M AF Klueh, RL Alexander, DJ Rieth, M TI The effect of tantalum on the mechanical properties of a 9Cr-2W-0.25V-0.07Ta-0.1C steel SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID MARTENSITIC STEELS; TENSILE PROPERTIES; BEHAVIOR AB An Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel has excellent strength and impact toughness before and after irradiation in the Fast Flux Test Facility (FFTF) and the High Flux Reactor (HFR). The ductile-brittle transition temperature (DBTT) increased only 32 degrees C after 28 dpa at 365 degrees C in FFTF, compared to a shift of approximate to 60 degrees C for a 9Cr-2WV steel the same as the 9Cr-2WVTa steel but without tantalum. This difference occurred despite the two steels having similar tensile properties before and after irradiation. The 9Cr-2WVTa steel has a smaller prior-austenite grain size, but otherwise microstructures are similar before irradiation and show similar changes during irradiation,The irradiation behavior of the 9Cr-2WVTa steel differs from the 9Cr-2WV steel and other similar steels in two ways: (1) the shift in DBTT of the 9Cr-2WVTa steel irradiated in FFTF does not saturate with fluence by approximate to 28 dpa, whereas for the 9Cr-2WV steel and most similar steels, saturation occurs at <10 dpa, and (2) the shift in DBTT for 9Cr-2WVTa steel irradiated in FFTF and HFR increased with irradiation temperature, whereas it decreased for the 9Cr-2WV steel, as it does for most similar steels. The improved properties of the 9Cr-2WVTa steel and the differences with other steels were attributed to tantalum in solution. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Forschungszentrum Karlsruhe, Inst Mat Forsch 2, D-76021 Karlsruhe, Germany. RP Klueh, RL (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6376, Oak Ridge, TN 37831 USA. RI Rieth, Michael/E-4245-2017 OI Rieth, Michael/0000-0002-6231-6241 NR 17 TC 36 Z9 48 U1 2 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD JUL PY 1999 VL 273 IS 2 BP 146 EP 154 DI 10.1016/S0022-3115(99)00035-5 PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 205GH UT WOS:000080812600004 ER PT J AU Williford, RE Weber, WJ Devanathan, R Cormack, AN AF Williford, RE Weber, WJ Devanathan, R Cormack, AN TI Native vacancy migrations in zircon SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DIFFUSION; RADIATION; AMORPHIZATION; SIMULATION; GLASS; PHASE AB Energy minimization methods were used to simulate the migration of Zr, Si, and O vacancies in zircon (ZrSiO(4)). Two sets of interatomic potentials were employed for comparison: one with O-Si-O three-body terms for the SiO(4), and one without. Results for Si were inconclusive. but consistent with maintaining the integrity of the SiO(4) molecular units. Both Zr and O vacancies can migrate on three-dimensional sublattice networks, thus supporting the experimentally observed diffusional isotropy. The predicted Zr vacancy migration energy (1.16-1.38 eV) was in good agreement with experiment if supplemented by Zr vacancy formation via Schottky or Frenkel defects (6.21-12.28 eV/defect). Oxygen vacancy migration energies were predicted to be 0.99-1.16 eV, somewhat lower than the experimental Value of 4.64 eV measured in natural zircons, which thus may include significant contributions from vacancy formation mechanisms at 3.31-6.52 eV/defect. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Dept Mat, Richland, WA 99352 USA. Alfred Univ, New York State Coll Ceram, Alfred, NY 14802 USA. RP Williford, RE (reprint author), Pacific NW Lab, Dept Mat, POB 999,MS K2-444, Richland, WA 99352 USA. EM re_williford@pnl.gov RI Weber, William/A-4177-2008; Devanathan, Ram/C-7247-2008 OI Weber, William/0000-0002-9017-7365; Devanathan, Ram/0000-0001-8125-4237 NR 38 TC 24 Z9 25 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD JUL PY 1999 VL 273 IS 2 BP 164 EP 170 DI 10.1016/S0022-3115(99)00026-4 PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 205GH UT WOS:000080812600006 ER PT J AU Aglan, H Gan, YX Chin, B Grossbeck, M AF Aglan, H Gan, YX Chin, B Grossbeck, M TI Fatigue failure analysis of V-4Ti-4Cr alloy SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID FUSION-REACTOR APPLICATIONS; PERCENT VANADIUM ALLOY; DISLOCATION SUBSTRUCTURE; PROPAGATION; WELDABILITY; NIOBIUM-8; FIELD AB In the present work, the fatigue fracture and failure behavior of a V-4Ti-4Cr has been studied. Static tears were conducted to study the overloading behavior and to select the magnitude of the stress level for the fatigue studies. Fatigue tests were performed using single edge notched (SEN) specimens under tension-tension load control conditions. Fatigue crack propagation (FCP) data such as the crack length, number of cycles, and hysteresis loops were recorded to calculate the crack speed, the energy release rate, and the change in work expended on damage formation and dissipative processes within the material. Parameters characterizing the fatigue fracture resistance of V-4Ti-4Cr alloy, namely the specific energy of damage (gamma'), and the dissipative coefficient (beta'), were determined from the fatigue data using the modified crack layer (MCL) theory. Fracture surface examination using scanning electron microscopy (SEM) revealed ductile failure mechanisms under tensile overloading conditions. The fatigue fracture surface of the V-4Ti-4Cr consists of three distinct regions, corresponding to the threshold, stable and unstable crack propagation stages. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. Auburn Univ, Ctr Mat Res & Educ, Auburn, AL 36849 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Aglan, H (reprint author), Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. NR 61 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD JUL PY 1999 VL 273 IS 2 BP 192 EP 202 DI 10.1016/S0022-3115(99)00029-X PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 205GH UT WOS:000080812600010 ER PT J AU Snead, LL Hay, JC AF Snead, LL Hay, JC TI Neutron irradiation induced amorphization of silicon carbide SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID BEAM-INDUCED AMORPHIZATION; SIC SINGLE-CRYSTALS; AMORPHOUS TRANSITION; ION-IMPLANTATION; ELASTIC-MODULUS; CERAMICS; TEMPERATURE; DEPENDENCE; GRAPHITE; HARDNESS AB This paper provides the properties of bulk stoichiometric silicon carbide which has been amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 degrees C to a total fast neutron fluence of 2.6 x 10(25) n/m(2). Amorphization was seen in both materials as evidenced by TEM, electron diffraction and X-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density (-10.8%), elastic modulus as measured using a nanoindentation technique (-45%), hardness as measured by nanoindentation (-45%), and standard Vickers hardness (-24%). Similar property changes are observed for the amorphized CVD SiC. Using measured thermal conductivity data for the CVD SiC sample, the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than similar to 125 degrees C. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37830 USA. RP Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37830 USA. EM z2n@ornl.gov NR 57 TC 74 Z9 77 U1 3 U2 30 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD JUL PY 1999 VL 273 IS 2 BP 213 EP 220 DI 10.1016/S0022-3115(99)00023-9 PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 205GH UT WOS:000080812600012 ER PT J AU Fowler, JS Volkow, ND Wang, GJ Ding, YS Dewey, SL AF Fowler, JS Volkow, ND Wang, GJ Ding, YS Dewey, SL TI PET and drug research and development SO JOURNAL OF NUCLEAR MEDICINE LA English DT Review DE PET imaging; fluorodeoxyglucose; drug development ID POSITRON-EMISSION-TOMOGRAPHY; CEREBRAL BLOOD-FLOW; MONOAMINE-OXIDASE-B; BRAIN MAO-B; IN-VIVO; PARKINSONS-DISEASE; RECEPTOR OCCUPANCY; DOPAMINE TRANSPORTER; BABOON BRAIN; SCHIZOPHRENIC-PATIENTS AB The use of PET to examine the behavioral, therapeutic and toxic properties of drugs and substances of abuse is emerging as a powerful new scientific tool. PET provides a new perspective on drug research by virtue of its ability to directly assess both pharmacokinetic and pharmacodynamic events in humans and in animals. These parameters can be assessed directly in the human body both in healthy Volunteers and in patients. Moreover, the new generation of high-resolution, small animal cameras hold the promise of introducing imaging in the early stages of drug development and make it possible to carry out longitudinal studies in animals and to study genetically altered animals. This places PET in a unique position to contribute significantly to the process of drug development through understanding the molecular mechanisms underlying drug action while addressing some very practical questions such as determining effective drug doses for clinical trials for new drugs, determining the duration of drug action and examining potential drug interactions. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NIDA NIH HHS [DA06891, DA09490]; NINDS NIH HHS [NS15380] NR 102 TC 98 Z9 104 U1 0 U2 7 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 USA SN 0161-5505 EI 1535-5667 J9 J NUCL MED JI J. Nucl. Med. PD JUL PY 1999 VL 40 IS 7 BP 1154 EP 1163 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 212LN UT WOS:000081218300018 PM 10405137 ER PT J AU Chatziioannou, AF Cherry, SR Shao, YP Silverman, RW Meadors, K Farquhar, TH Pedarsani, M Phelps, ME AF Chatziioannou, AF Cherry, SR Shao, YP Silverman, RW Meadors, K Farquhar, TH Pedarsani, M Phelps, ME TI Performance evaluation of microPET: A high-resolution lutetium oxyorthosilicate PET scanner for animal imaging SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE PET; instrumentation; performance evaluation; animal imaging ID POSITRON EMISSION TOMOGRAPHY; ATTENUATION CORRECTION; COMPUTED-TOMOGRAPHY; SPATIAL-RESOLUTION; MULTICHANNEL PMT; GENE-EXPRESSION; 3D PET; DESIGN; SENSITIVITY; DETECTORS AB A new dedicated PET scanner, microPET, was designed and developed at the University of California, Los Angeles, for imaging small laboratory animals. The goal was to provide a compact system with superior spatial resolution at a fraction of the cost of a clinical PFT scanner. Methods: The system uses fiberoptic readout of individually cut lutetium oxyorthosilicate (LSO) crystals to achieve high spatial resolution. Each microPET detector consists of an 8 X 8 array of 2 x 2 x 10-mm LSO scintillation crystals that are coupled to a 64-channel photomultiplier tube by optical fibers. The tomograph consists of 30 detectors in a continuous ring with a 17.2-cm diameter and fields of view (FOVs) of 11.25 cm in the transaxial direction and 1.8 cm in the axial direction. The system has eight crystal rings and no interplane septa. It operates exclusively in the three-dimensional mode and has an electronically controlled bed that is capable of wobbling with a radius of 300 mu m. We describe the performance of the tomograph in terms of its spatial, energy and timing resolution, as well as its sensitivity and counting-rate performance. We also illustrate its overall imaging performance with phantom and animal studies that demonstrate the potential applications of this device to biomedical research. Results: Images reconstructed with three-dimensional filtered backprojection show a spatial resolution of 1.8 mm at the center of the FOV (CFOV), which remains <2.5 mm for the central 5 cm of the transaxial FOV. The resulting volumetric resolution of the system is <8 mu L. The absolute system sensitivity measured with a 0.74 MBq (20 mu Ci) Ge-68 point source at the CFOV is 5.62 Hz/kBq. The maximum noise equivalent counting rate obtained with a 6.4-cm diameter cylinder spanning the central 56% of the FOV is 10 kcps, whereas the scatter fraction is 37% at the CFOV for an energy window of 250-650 keV and the same diameter cylinder. Conclusion: This is the first PET scanner to use the new scintillator LSO and uses a novel detector design to achieve high volumetric spatial resolution. The combination of imaging characteristics of this prototype system (resolution, sensitivity, counting rate performance and scatter fraction) opens up new possibilities in the study of animal models with PET. C1 Univ Calif Los Angeles, Sch Med, Crump Inst Biol Imaging, Dept Mol & Med Pharmacol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, US DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Chatziioannou, AF (reprint author), Univ Calif Los Angeles, Sch Med, Crump Inst Biol Imaging, Dept Mol & Med Pharmacol, 700 Westwood Plaza,Box 951770, Los Angeles, CA 90095 USA. FU NCI NIH HHS [P50 CA086306, P50 CA086306-01, R01 CA69370] NR 40 TC 267 Z9 275 U1 1 U2 10 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 USA SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD JUL PY 1999 VL 40 IS 7 BP 1164 EP 1175 PG 12 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 212LN UT WOS:000081218300019 PM 10405138 ER PT J AU Sloof, GW Visser, FC Comans, EFI Bax, JJ Teerlink, T van der Vusse, GJ Knapp, FF AF Sloof, GW Visser, FC Comans, EFI Bax, JJ Teerlink, T van der Vusse, GJ Knapp, FF TI Metabolism of radioiodinated fatty acid analogs in ischemic and hypoxic canine myocardium SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE fatty acids; myocardial ischemia ID PHENYL PENTADECANOIC ACID; EMISSION TOMOGRAPHY; HEPTADECANOIC ACID; BLOOD-FLOW; 15-(P-IODOPHENYL)-3,3-DIMETHYLPENTADECANOIC ACID; CARDIAC METABOLISM; LIPID-METABOLISM; PALMITIC ACID; IODINE-123-BMIPP; HEART AB Myocardial metabolism of 17-[I-123]-iodoheptadecanoic acid (IHDA), 15-(p-[I-131]-iodophenyl)pentadecanoic acid (pIPPA) and 15-(p-[I-125]-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPP) was assessed during ischemia and hypoxia; The simultaneous investigation allowed us to evaluate differences in metabolic handling of these three fatty acids. Methods: In 17 open-chest dogs, the left ascending coronary artery was, cannulated and extracorporeal bypass (ECB) perfused. In 3 dogs, ECB flow was kept normal, and these control experiments showed that kinetics of the radioiodinated fatty acids were not affected by the ECB technique itself. In 9 dogs, ECB flow was reduced to one third (ischemia), and in 5 dogs, the ECB area was perfused with venous blood and was kept at control values (hypoxia). After simultaneous intraveneous injection of IHDA, pIPPA and DMIPP, seven paired biopsy specimens from the native and ECB-perfused myocardium were taken over an assay period of 35 min. Total activity and the distribution in the aqueous phase and lipid fractions were determined, and time-activity curves were constructed. Results: In ischemic (Is) but not in hypoxic (Hy) myocardium, peak total activity of IHDA, pIPPA and DMIPP decreased significantly versus normal (N) myocardium (IHDA: N = 700 +/- 267 versus Is = 335 +/- 158 dpm/mg/mCi; pIPPA: N = 988 +/- 318 versus Is = 438 +/- 180 dpm/mg/mCi; DMIPP: N = 352 +/- 146 versus Is = 179 +/- 82 dpm/mg/mCi; all P values < 0.001). The relative decrease was similar for IHDA, pIPPA or DMIPP. Half-time values of total activity were prolonged for IHDA and pIPPA but were shortened for DMIPP in ischemic and hypoxic myocardium (IHDA: N = 22, Is = 44 and Hy = 50 min; pIPPA: N = 24, Is = 95 and Hy = 169 min; DMIPP: N = 528, Is = 409 and Hy = 115 min). The aqueous phase activity for IHDA, pi PPA and DMIPP decreased significantly versus normal myocardium in both ischemic (IHDA: N = 71% +/- 9% versus Is = 36% +/- 9%, P < 0.001; pIPPA: N = 62% +/- 10% versus Is = 25% +/- 8%, P < 0.001; DMIPP: N = 26% +/- 11% versus Is = 18% +/- 3%, P < 0.05) and hypoxic (IHDA: N = 76% +/- 8% versus Hy = 62% +/- 8%, P < 0.05; pIPPA: N = 66% +/- 8% versus Hy = 46% +/- 10%, P < 0.05; DMIPP: N = 32% +/- 6% versus Hy = 24% +/- 4%, P < 0.05) myocardium. The relative decrease was significantly highest for pIPPA and lowest for DMIPP. Incorporation into triacylglycerols increased significantly for IHDA, pIPPA and DMIPP in both ischemic and hypoxic myocardium. In normal myocardium, DMIPP was already mainly incorporated into triacylglycerols. Activity of IHDA and pIPPA in acylcarnitine increased significantly in ischemic and hypoxic myocardium. Conclusion: Kinetics of the radioiodinated fatty acid analogs in myocardium are altered during oxygen deprivation in a similar fashion as documented in literature for natural fatty acids. However, the changes were different between IHDA, pIPPA and DMIPP, suggesting different metabolic handling and thus reflecting different aspects of myocardial fatty acid metabolism. C1 Free Univ Amsterdam Hosp, Dept Nucl Med, Amsterdam, Netherlands. Free Univ Amsterdam Hosp, Dept Cardiol, Amsterdam, Netherlands. Free Univ Amsterdam Hosp, Metab Lab, Amsterdam, Netherlands. Maastricht Univ, Cardiovasc Res Inst Maastricht, Dept Physiol, Maastricht, Netherlands. Oak Ridge Natl Lab, Nucl Med Grp, Oak Ridge, TN USA. RP Sloof, GW (reprint author), Univ Amsterdam, Acad Med Ctr, Dept Nucl Med, Meibergdreef 9, NL-1105 AZ Amsterdam, Netherlands. NR 39 TC 2 Z9 2 U1 0 U2 0 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 USA SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD JUL PY 1999 VL 40 IS 7 BP 1204 EP 1215 PG 12 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 212LN UT WOS:000081218300024 PM 10405143 ER PT J AU Casanova, H Thomason, MG Dongarra, JJ AF Casanova, H Thomason, MG Dongarra, JJ TI Stochastic performance prediction for iterative algorithms in distributed environments SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article DE convergence; distributed-memory; iterative algorithm; Markov chain; multiuser; parallel; performance prediction; stochastic modeling ID PARALLEL ASYNCHRONOUS ALGORITHMS; CONVERGENCE AB The parallelization of iterative algorithms is an important issue for efficient solution of large numerical problems. Several theoretical results concerning sufficient conditions for. and speed of convergence of parallel iterative algorithms are available. However, those results usually do not take into account the processor workloads and network communications at the application level. The approach in this paper develops a Markov chain based on random variables which describe aspects of the multiuser, distributed-memory environment and the phases of the algorithm. The performance characterization addresses stochastic characteristics of the algorithmic execution time such as mean values and standard deviations. We present simulation results as well as experimental results over different time periods. The results provide information about the impact of distributed environment and implementation style on long-run expected execution time characteristics. (C) Academic Press. C1 Univ Calif San Diego, Dept Comp Sci & Engn, La Jolla, CA 92093 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Math Sci Sect, Oak Ridge, TN 37821 USA. RP Casanova, H (reprint author), Univ Calif San Diego, Dept Comp Sci & Engn, La Jolla, CA 92093 USA. RI Dongarra, Jack/E-3987-2014 NR 31 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD JUL PY 1999 VL 58 IS 1 BP 68 EP 91 DI 10.1006/jpdc.1999.1543 PG 24 WC Computer Science, Theory & Methods SC Computer Science GA 214TG UT WOS:000081343200004 ER PT J AU Sorenson, JM Hura, G Soper, AK Pertsemlidis, A Head-Gordon, T AF Sorenson, JM Hura, G Soper, AK Pertsemlidis, A Head-Gordon, T TI Determining the role of hydration forces in protein folding SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SUPERCOOLED LIQUID WATER; X-RAY-DIFFRACTION; HYDROPHOBIC SURFACES; MOLECULAR-DYNAMICS; GLOBULAR-PROTEINS; ATTRACTIVE FORCES; CLATHRATE-LIKE; KINETICS; THERMODYNAMICS; HETEROPOLYMERS AB This article describes a combined experimental, theoretical, and computational effort to show how the complexity of aqueous hydration can influence the structure, folding and aggregation, and stability of model protein systems. The unification of the theoretical and experimental work is the development or discovery of effective amino acid interactions that implicitly include the effects of aqueous solvent. We show that consideration of the full range of complexity of aqueous hydration forces such as many-body effects, long-ranged character of aqueous solvation, and the assumptions made about the degree of protein hydrophobicity can directly impact the observed structure, folding, and stability of model protein systems. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Grad Grp Biophys, Berkeley, CA 94720 USA. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. Univ Texas, SW Med Ctr, Dept Biochem, Dallas, TX 75235 USA. RP Head-Gordon, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RI Head-Gordon, Teresa/E-5818-2011 NR 89 TC 79 Z9 79 U1 1 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5413 EP 5426 DI 10.1021/jp990434k PG 14 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200001 ER PT J AU Son, SF Asay, BW Henson, BF Sander, RK Ali, AN Zielinski, PM Phillips, DS Schwarz, RB Skidmore, CB AF Son, SF Asay, BW Henson, BF Sander, RK Ali, AN Zielinski, PM Phillips, DS Schwarz, RB Skidmore, CB TI Dynamic observation of a thermally activated structure change in 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) by second harmonic generation SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID HOT-SPOTS; TRIAMINOTRINITROBENZENE; DECOMPOSITION; IMPACT; SHOCK AB Using optical second harmonic generation (SHG) we observe, for the first time, a structural change in the energetic material (dry-aminated production grade) TATB (1,3,5-triamino-2,4,6-trinitrobenzene) upon heating. This structure change is verified by X-ray powder diffraction (XPD). The kinetics of this structure change are measured and are found to closely match commonly accepted thermal decomposition parameters for the first step, analogous to observations made for the beta to delta phase transition in HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). Consequently, these solid structure transitions appear to be coupled to the chemical decomposition mechanism or it may be the first physical process occurring. We apply this technique as a diagnostic to an ignition experiment. This experiment demonstrates that the structure change can be rapid (it is thermally activated) and that SHG can be used to indicate not only the solid structure change (large increase in SHG intensity) but also the onset to significant decomposition (subsequent drop in SHG intensity). The ability to selectively change the efficiency of the SHG, in a single piece of explosive, is also demonstrated and may have novel nonlinear optical applications. This application of SHG to TATE constitutes a fundamentally new probe in the dynamics of TATE decomposition, ignition, and combustion and may have application to optical integrated devices for frequency conversion and information encoding. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Son, SF (reprint author), Univ Calif Los Alamos Natl Lab, MS C920, Los Alamos, NM 87545 USA. OI Son, Steven/0000-0001-7498-2922 NR 20 TC 30 Z9 31 U1 2 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5434 EP 5440 DI 10.1021/jp983307h PG 7 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200003 ER PT J AU Gruen, DM Redfern, PC Horner, DA Zapol, P Curtiss, LA AF Gruen, DM Redfern, PC Horner, DA Zapol, P Curtiss, LA TI Theoretical studies on nanocrystalline diamond: Nucleation by dicarbon and electronic structure of planar defects SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID GRAIN-BOUNDARIES; EXCHANGE-ENERGY; DENSITY; PLASMAS; FILMS; MICROSTRUCTURE; APPROXIMATION; GROWTH AB Density functional theory and ab initio molecular orbital theory have been used to calculate the energetics of C-2 insertion into C9H12 and C9H14 clusters that model unhydrided and monohydrided (100) diamond surfaces, respectively. The reaction of C-2 with either the C9H12 Or C9H14 cluster is exothermic by more than 100 kcal/mol, but the lowest energy product is different for the two clusters. The reaction of singlet C-2 with the C=C double bond of the C9H12 cluster leads to either carbene structures or a cyclobutyne-like structure, with the former having the lower energy at both the HF/6-31G* and B3LYP/6-31G* levels of theory. No barrier for insertion into the C=C double bond of the C9H12 cluster was found at the HF/6-31G* and B3LYP/6-31G* levels of theory. The reaction of singlet C-2 with the HC-CH single bond or C-H bonds of the C9H14 cluster leads to a structure having a cyclobutene-like geometry. We propose that the disparate nucleation rates of diamond crystallites grown in hydrogen-rich vs hydrogen-poor C-60/Ar microwave plasmas are accounted for qualitatively by these results. The carbon dimer, C-2, is a possible growth or nucleation species produced by fragmentation of C-60 Periodic density functional calculations of the electronic structure of a simple model of an sp(2)-bonded diamond grain boundary show that pi-bonded planar defects introduce new electronic bands into the fundamental band gap of diamond. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. N Cent Coll, Naperville, IL 60566 USA. RP Curtiss, LA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Zapol, Peter/G-1810-2012 OI Zapol, Peter/0000-0003-0570-9169 NR 29 TC 46 Z9 46 U1 1 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 JUL 1 PY 1999 VL 103 IS 26 BP 5459 EP 5467 DI 10.1021/jp990165y PG 9 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200007 ER PT J AU Walker, TA Raghavan, SR Royer, JR Smith, SD Wignall, GD Melnichenko, Y Khan, SA Spontak, RJ AF Walker, TA Raghavan, SR Royer, JR Smith, SD Wignall, GD Melnichenko, Y Khan, SA Spontak, RJ TI Enhanced miscibility of low-molecular-weight polystyrene polyisoprene blends in supercritical CO2 SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SMALL-ANGLE NEUTRON; COMPRESSED FLUID ANTISOLVENT; BLOCK-COPOLYMER MELTS; CARBON-DIOXIDE; POLYMER BLENDS; HIGH-PRESSURE; HOMOPOLYMER BLENDS; DIBLOCK COPOLYMERS; PHASE-SEPARATION; SCATTERING AB While ongoing efforts continue to explore the high-pressure phase equilibria of polymer blends, few studies have attempted to address the impact of a supercritical (sc) fluid on such equilibria. In this work, we report on the phase behavior of an upper critical solution temperature (UCST) polymer blend in the presence of supercritical, carbon dioxide (scCO(2)), a nonselective plasticizing agent. Blends composed of low-molecular-weight polystyrene and polyisoprene have been examined as a function of temperature in scCO(2) by visual inspection, small-angle neutron scattering, and spectrophotometry. In the presence of scCO(2), the cloud point temperature is depressed by as much as 28 degrees C, depending on both blend composition and CO2 pressure. Complementary studies performed with nitrogen decouple the plasticization efficacy of CO2 from free-volume compression due to hydrostatic pressure. Existence of a pressure yielding a maximum in CO2-induced cloud point depression is established. These results provide evidence for enhanced polymer miscibility as a result of the plasticizing effectiveness and tunable solubility of scCO(2). C1 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 Chem Engn, Raleigh, NC 27695 USA. OI Wignall, George/0000-0002-3876-3244 NR 32 TC 29 Z9 30 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5472 EP 5476 DI 10.1021/jp990551f PG 5 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200009 ER PT J AU Wang, HH VanZile, ML Schlueter, JA Geiser, U Kini, AM Sche, PP Koo, HJ Whangbo, MH Nixon, PG Winter, RW Gard, GL AF Wang, HH VanZile, ML Schlueter, JA Geiser, U Kini, AM Sche, PP Koo, HJ Whangbo, MH Nixon, PG Winter, RW Gard, GL TI In-plane ESR microwave conductivity measurements and electronic band structure studies of the organic superconductor beta ''-(BEDT-TTF)(2)SF5CH2CF2SO3 SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE BEDT-TTF; AMBIENT-PRESSURE SUPERCONDUCTIVITY; CHARGE-TRANSFER SALT; SPIN-RESONANCE; BETA-(BEDT-TTF)2I3; TEMPERATURE; CONDUCTORS; DISORDER; METALS; SYSTEM AB The electronic structure of the organic superconductor beta "-(BEDT-TTF)(2)SF5CH2CF2SO3 (BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) was characterized with the use of electron spin resonance (ESR) spectroscopy and electronic band structure calculations. The room-temperature ESR line width is 24-27 G in the plane of a donor molecule layer (i.e., in the ab-plane) and similar to 32 G along the normal to this plane (i.e., along the c*-direction). The ab-plane anisotropy of the microwave conductivity was extracted for the first time from the ESR Dysonian line shape analysis. The in-plane conductivity varies sinusoidally, is maximal along the interstack direction (b-axis), and is minimal along the donor stack direction (a-axis). The Fermi surfaces of the title compound consist of a 2D hole pocket and a pair of 1D wavy lines. The directions for the in-plane conductivity maximum and minimum are in excellent agreement with the electronic band structure calculated for beta "-(BEDT-TTF)(2)SF5CH2CF2SO3, and the origin of the in-plane conductivity anisotropy lies in the one-dimensional part of the Fermi surface. This is the first time that an organic conductor shows Dysonian ESR line shape due to its 2D and strongly metallic nature, yet the 1D character is revealed simultaneously through the in-plane conductivity anisotropy. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. N Carolina State Univ, Dept Chem, Raleigh, NC 27695 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Wang, HH (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Kini, Aravinda/F-4467-2012 NR 30 TC 12 Z9 12 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5493 EP 5499 DI 10.1021/jp991268j PG 7 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200012 ER PT J AU Jirsak, T Dvorak, J Rodriguez, JA AF Jirsak, T Dvorak, J Rodriguez, JA TI Chemistry of thiophene on ZnO, S/ZnO, and Cs/ZnO surfaces: Effects of cesium on desulfurization processes SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID OXIDE SURFACES; ADSORPTION; SULFUR; OXIDATION; PHOTOEMISSION; CHEMISORPTION; DECOMPOSITION; REACTIVITY; HYDROGEN; S-2 AB The adsorption of thiophene (C4H4S) On clean ZnO and oxide surfaces precovered with S and Ca has been studied using synchrotron-based high-resolution photoemission and ab initio self-consistent-field (SCF) calculations. On polycrystalline ZnO, C4H4S is weakly chemisorbed, and most desorbs at temperatures below 250 K. A very small fraction of the adsorbed C4H4S (similar to 0.02 monolayer) that interacts with O-unsaturated Zn sites decomposes on the oxide surface. S adatoms weaken the bonding interactions of thiophene on ZnO, whereas Cs adatoms enhance the adsorption energy of the molecule by at least 5-10 kcal/mol and facilitate the cleavage of C-S bonds. Pure metallic Cs reacts vigorously with C4H4S decomposing the molecule at: very low temperatures (100-200 K). The: Cs atoms supported on ZnO are in an ionic state (Csdelta+), but they retain a large chemical affinity for thiophene. Small amounts of Cs (similar to 0.2 monolayer) are enough to activate the oxide surface. Results of ab initio SCF calculations indicate that the bonding interactions of thiophene with the (0001)-Zn and (000 (1) over bar)-O faces of ZnO are weak, and promotion with Cs adatoms considerably improves the energetics for C4H4S adsorption and C-S bond breaking. The Cs adatoms provide occupied states that are very efficient for bonding interactions with the frontier orbitals of C4H4S and other S-containing molecules. This should lead to an improvement in the performance of ZnO as a sorbent in desulfurization processes. 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 62 TC 46 Z9 48 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5550 EP 5559 DI 10.1021/jp991051p PG 10 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200020 ER PT J AU Jiang, JW Prausnitz, JM AF Jiang, JW Prausnitz, JM TI Molecular thermodynamics for protein precipitation with a polyelectrolyte SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MULTIPLE BONDING SITES; SMALL-ANGLE SCATTERING; MEAN SPHERICAL MODEL; PHASE-EQUILIBRIA; HARD-SPHERES; ASYMMETRIC ELECTROLYTES; SILICA SUSPENSIONS; ASSOCIATING FLUIDS; ATTRACTIVE FORCES; CATIONIC POLYMERS AB A molecular-thermodynamic framework is developed for phase equilibria in an aqueous system containing a charged globular protein and an oppositely charged linear polyelectrolyte. The globular protein is represented by a spherical macroion with its colons; the linear polyelectrolyte is represented by a charged hard-sphere chain (polyion) with corresponding counterions. The potential of mean force contains Coulombic interactions between macroions, polyions, and small ions; long-range dispersion attractions between protein macroions; and hydrophobic macroion-polyion and macroion-macroion associations. Analytic expressions for thermodynamic properties are obtained, and liquid-liquid phase equilibria (precipitation) are calculated for model systems. Adding polyelectrolyte to a protein solution leads to precipitation, but further addition of polyelectrolyte leads to redissolution of the protein. This destabilization-restabilization phenomenon follows from electrostatic interactions with coupled polymer adsorption. The effects on phase equilibria of protein charge, protein size, association energy between protein-polyion, polyion chain length, and polyion charge density are investigated for model systems and compared with experimental data. Brief consideration is given to fractional precipitation for binary aqueous mixtures of proteins with different charge densities. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI JIANG, Jianwen/G-1505-2013; OI Jiang, Jianwen/0000-0003-1310-9024 NR 62 TC 26 Z9 26 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 1 PY 1999 VL 103 IS 26 BP 5560 EP 5569 DI 10.1021/jp990455e PG 10 WC Chemistry, Physical SC Chemistry GA 216AB UT WOS:000081417200021 ER PT J AU Lin, JN Lu, GX Du, J Su, MZ Loong, CK Richardson, JW AF Lin, JN Lu, GX Du, J Su, MZ Loong, CK Richardson, JW TI Phase transition and crystal structures of BaZn2Si2O7 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE crystal structure; phase transitions; neutron scattering; inorganic compounds AB The phase transition and crystal structures of the low (LT) and high (HT) temperature phases of BaZn2Si2O7 were studied by neutron and X-ray diffraction techniques. BaZn2Si2O7 undergoes a first-order phase transition at about 250 degrees C. The LT phase of BaZn2Si2O7 is iso-structural with BaCo2Si2O7, crystallizing in the monoclinic space group C2/c with the lattice constants, a = 7.2782(43 Angstrom, b = 12.8009(7) Angstrom, c = 13.6869(7) Angstrom and beta = 90.093(6)degrees at room temperature. The structure of the HT phase, which was established by analyzing the X-lay powder-diffraction data using the direct method, crystallizes in the orthorhombic space group Ccm2(1), with the lattice constants, a = 7.6199(4) Angstrom, b = 13.0265(6) Angstrom and c = 6.7374(2)Angstrom at 280 degrees C. The underlying frameworks for both structures ale similar and can be regarded as an extensive three-dimensional tetrahedral system [Zn2Si2O7], in which both silicon and zinc atoms are coordinated tetrahedrally by oxygen atoms. The barium atoms are located within the channels of the framework, but their coordination polyhedra are different for the LT and HT structures. The lower coordination number of Ba atoms and the breaking of the Ba-O bonds in the HT phase may account for the endothermal behavior of the phase transition. The coefficient of volume expansion of the HT phase is smaller than that of the LT phase, and over the 280 degrees C-900 degrees C temperature range the cell constant along the a-axis decreases with increasing temperature. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Peking Univ, Dept Chem Mat, State Key Lab Rare Earth Mat Chem & Applicat, Beijing 100871, Peoples R China. Argonne Natl Lab, Div Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Lin, JN (reprint author), Peking Univ, Dept Chem Mat, State Key Lab Rare Earth Mat Chem & Applicat, Beijing 100871, Peoples R China. NR 11 TC 24 Z9 24 U1 5 U2 25 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD JUL PY 1999 VL 60 IS 7 BP 975 EP 983 DI 10.1016/S0022-3697(99)00004-9 PG 9 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 208DZ UT WOS:000080976100017 ER PT J AU Yukhimuk, AK Yukhimuk, VA Sirenko, OK Voitenko, YM AF Yukhimuk, AK Yukhimuk, VA Sirenko, OK Voitenko, YM TI Parametric excitation of electromagnetic waves in a magnetized plasma SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID INSTABILITY; GENERATION; RADIATION AB The parametric interaction of an upper-hybrid pump wave with kinetic Alfven and electromagnetic waves that propagate in parallel and perpendicular directions to the ambient magnetic field is investigated on the basis of two-fluid magnetohydrodynamics. A nonlinear dispersion relation describing three-wave interaction and instability growth rates are found. The theoretical results are used for the interpretation of satellite observations in the magnetospheric plasma. It is shown that as a result of the decay of an upper-hybrid wave. electromagnetic waves propagating in both parallel and perpendicular directions to the ambient magnetic field are generated. The instability growth rate is much higher in the case of left-polarized electromagnetic wave generation than in the case of ordinary electromagnetic wave generation. The nonlinear parametric processes studied here could also take place during powerful bursts on the Sun, and in the magnetosphere of Jupiter. C1 Natl Acad Sci Ukraine, Main Astron Observ, UA-252650 Kiev 22, Ukraine. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Yukhimuk, AK (reprint author), Natl Acad Sci Ukraine, Main Astron Observ, UA-252650 Kiev 22, Ukraine. NR 20 TC 6 Z9 6 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD JUL PY 1999 VL 62 BP 53 EP 64 DI 10.1017/S0022377899007709 PN 1 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 247FK UT WOS:000083210300003 ER PT J AU Chen, W Toda, A Moon, IK Wunderlich, B AF Chen, W Toda, A Moon, IK Wunderlich, B TI Analysis of transitions of liquid crystals and conformationally disordered crystals by temperature-modulated calorimetry SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE liquid crystal; conformationally disordered crystal (condis crystal); reversible phase transition; irreversible phase transition; temperature-modulated calorimetry ID DIFFERENTIAL SCANNING CALORIMETRY; DSC MEASUREMENTS; CRYSTALLIZATION; POLY(ETHYLENE-TEREPHTHALATE); POLYMERS C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Hiroshima Univ, Fac Arts & Sci, Higashihiroshima 739, Japan. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 26 TC 11 Z9 11 U1 1 U2 4 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 JUL 1 PY 1999 VL 37 IS 13 BP 1539 EP 1544 DI 10.1002/(SICI)1099-0488(19990701)37:13<1539::AID-POLB20>3.0.CO;2-T PG 6 WC Polymer Science SC Polymer Science GA 206KT UT WOS:000080878800020 ER PT J AU Urbina, A Paez, TL O'Gorman, C Barney, P Jungst, RG Ingersoll, D AF Urbina, A Paez, TL O'Gorman, C Barney, P Jungst, RG Ingersoll, D TI Reliability of rechargeable batteries in a photovoltaic power supply system SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT 21st International Power Sources Symposium on Research amd Development in Non-Mechanical Electrical Power Sources CY MAY 10-12, 1999 CL BRIGHTON, ENGLAND SP AEA Technol Batteries, Batteries Int, Battery Power Prod Technol, Brittania Refined Metals Ltd, BTR Power Syst, Hawker Batteries Grp Ltd, SAFT-NIFE, Missiles Space Batteries Ltd, Ultralife Batteries, Varta Ltd, Yardney Tech Prod DE photovoltaics; lead-acid batteries; mathematical modelling; hybrid power supplies AB We investigated the reliability of a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. A model system was constructed for this that includes the solar resource, the photovoltaic power supply system, the rechargeable battery and a load. The solar resource and the system load are modelled as stochastic processes. The photovoltaic system and the rechargeable battery are modelled deterministically, and an artificial neural network is incorporated into the model of the rechargeable battery to simulate damage that occurs during deep discharge cycles. The equations governing system behaviour are solved simultaneously in the Monte Carlo framework, and a first passage problem is solved to assess system reliability, (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Lithium Battery R&D Dept, Albuquerque, NM 87185 USA. RP Paez, TL (reprint author), Sandia Natl Labs, Lithium Battery R&D Dept, 9119,Mail Stop 0557, Albuquerque, NM 87185 USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUL-AUG PY 1999 VL 80 IS 1-2 BP 30 EP 38 DI 10.1016/S0378-7753(99)00062-2 PG 9 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 207MJ UT WOS:000080940400008 ER PT J AU Nagasubramanian, G Ingersoll, D Doughty, D Radzykewycz, D Hill, C Marsh, C AF Nagasubramanian, G Ingersoll, D Doughty, D Radzykewycz, D Hill, C Marsh, C TI Electrical and electrochemical performance characteristics of large capacity lithium-ion cells SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT 21st International Power Sources Symposium on Research amd Development in Non-Mechanical Electrical Power Sources CY MAY 10-12, 1999 CL BRIGHTON, ENGLAND SP AEA Technol Batteries, Batteries Int, Battery Power Prod Technol, Brittania Refined Metals Ltd, BTR Power Syst, Hawker Batteries Grp Ltd, SAFT-NIFE, Missiles Space Batteries Ltd, Ultralife Batteries, Varta Ltd, Yardney Tech Prod DE lithium-ion rechargeable cells AB We are currently evaluating large capacity (20-40 Ah) Bluestar (cylindrical) and Yardney (prismatic) lithium-ion cells for their electrical and electrochemical performance characteristics at different temperatures, The cell resistances were nearly constant from room temperature down to -20 degrees C, but increased by over 10 times at -40 degrees C. The specific energies and powers, as well as the energy densities and power densities are high and did not reach a plateau even at the highest discharge rates tested. For example, the prismatic lithium-ion cells gave close to 280 Wh dm(-3) from a 4 A discharge and 249 Wh dm(-3) at 20 A, both at room temperature. For the same current range the specific energy values were 102 Wh kg(-1) and 91 Wh kg(-1). Cycle life and other electrical and electrochemical properties of the cells will be presented. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Lithium Battery Res & Dev Dept 1521, Albuquerque, NM 87185 USA. USAF, Res Lab, Philips Res Site, Kirtland AFB, NM 87117 USA. Yardney Tech Prod, Pawcatuck, CT 06379 USA. RP Nagasubramanian, G (reprint author), Sandia Natl Labs, Lithium Battery Res & Dev Dept 1521, POB 5800, Albuquerque, NM 87185 USA. NR 4 TC 9 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUL-AUG PY 1999 VL 80 IS 1-2 BP 116 EP 118 DI 10.1016/S0378-7753(98)00255-9 PG 3 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 207MJ UT WOS:000080940400022 ER PT J AU Moody, KJ Grant, PM AF Moody, KJ Grant, PM TI Nuclear forensic analysis of thorium SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article AB A comprehensive radiochemical isolation procedure and data analysis/interpretation method for the nuclear forensic investigation of Th has been developed. The protocol includes sample dissolution, chemical separation, nuclear counting techniques, consideration of isotopic parent-daughter equilibria, and data interpretation tactics. Practical application of the technology was demonstrated by analyses of a questioned specimen confiscated at an illegal drug synthesis laboratory by law enforcement authorities. C1 Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Isotope Sci Div, Livermore, CA 94550 USA. RP Moody, KJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, L-178, Livermore, CA 94550 USA. NR 8 TC 6 Z9 6 U1 1 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 1999 VL 241 IS 1 BP 157 EP 167 DI 10.1007/BF02347304 PG 11 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 219LF UT WOS:000081608200023 ER PT J AU Bennahmias, M Radousky, HB Lorenzana, HE Goodwin, TJ Shelton, RN AF Bennahmias, M Radousky, HB Lorenzana, HE Goodwin, TJ Shelton, RN TI Raman and magnetic susceptibility evidence for a structural transition in (Eu(1.5-x)PrxCe(0.5))Sr2Cu2NbO10 compounds SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID ND; SM; (R1.5-XPRXCE0.5)SR2CU2NBO10-DELTA; SUPERCONDUCTIVITY; CERAMICS; PR; EU AB Understanding the unique role that Pr hybridization plays in promoting both the suppression of superconductivity and the onset of complex magnetism in high-T-c cuprates continues to be a dynamic area of research. Complex magnetic behavior is well known to occur in the (Pr1.5Ce0.5)Sr2Cu2MO10 (M = Nb Or Ta) compounds. Previously, two temperature-dependent transitions have been identified through magnetic susceptibility studies for the series of solid solutions (Eu1.5-x PrxCe0.5)Sr2Cu2NbO10 (0.0 less than or equal to x less than or equal to 1.5). In this paper, we present new measurements of the Raman-active modes and the magnetic susceptibility for these latter compounds. The data indicate a discontinuity in concentration space at a Pr doping level of x = 1.0, that we interpret as the signature of a subtle phase transition. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Radousky, HB (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94551 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD JUL PY 1999 VL 30 IS 7 BP 543 EP 545 PG 3 WC Spectroscopy SC Spectroscopy GA 217CR UT WOS:000081482700009 ER PT J AU Grealy, M Sreenan, JM AF Grealy, M Sreenan, JM TI Effect of adenylyl cyclase activation on intracellular and extracellular cAMP and cGMP in preimplantation cattle blastocysts SO JOURNAL OF REPRODUCTION AND FERTILITY LA English DT Article ID SMOOTH-MUSCLE CELLS; CYCLIC-AMP; NITRIC-OXIDE; ISOLATED UTERUS; GUINEA-PIG; PROLIFERATION; EMBRYOS; STIMULATION; OOCYTES; GMP AB The effects of direct and indirect activation of adenylyl cyclase on the production of intracellular and extracellular cAMP and cGMP by 13- to 16-day-old cattle embryos were determined. Embryos were incubated for 2h in a Krebs Ringer bicarbonate medium containing the phosphodiesterase inhibitor isobutyl methylxanthine, to which stimulating agents forskolin (100 mu mol l(-1)), cholera toxin (2 mu g ml(-1)), or both were added. Total (intra-and extracellular) basal cAMP and cGMP concentrations ranged from 6.65 +/- 0.895 to 3.4 +/- 0.708 fmol mu g(-1) protein in 13-day-old embryos and from 4.05 +/- 1.151 to 0.19 +/- 0.041 fmol mu g(-1) protein in 16-day-old embryos. Forskolin induced an increase (P < 0.001) in cAMP that ranged from 5.4-fold on day 13 to 2.7-fold on day 16, whereas cholera toxin induced an increase (P < 0.001) that ranged from 30-fold at day 13 to 21-fold at day 16, similar to the effect of forskolin and cholera toxin combined. Individually, forskolin and cholera toxin had no effect on cGMP concentrations, but together they induced an increase (P < 0.05). cAMP (P < 0.01) and cGMP (P < 0.001) concentrations decreased with embryo age from day 13 to day 16 for all treatments; the decrease was greater for cGMP than cAMP (5-24-fold versus 1.6-3.3-fold, respectively). It is concluded that inducible adenylyl cyclase is present in 13- to 16-day-old cattle embryos and that the embryos secrete cAMP and cGMP into the incubation medium. Ln addition, basal and inducible concentrations of cAMP and cGMP decrease with embryo age from day 13 to day 16. These observations indicate that cAMP and cGMP may have a role in the rapid embryonic cell proliferation that occurs at this time or in signalling to the endometrium. C1 TEAGASC, Agr & Food Dev Author, Anim Reprod Dept, Athenry, Co Galway, Ireland. RP Grealy, M (reprint author), Natl Univ Ireland Univ Coll Galway, Dept Biochem, Galway, Ireland. NR 31 TC 7 Z9 7 U1 0 U2 0 PU JOURNALS OF REPRODUCTION FERTILITY LTD PI CAMBRIDGE PA 22 NEWMARKET RD, CAMBRIDGE CB5 8DT, ENGLAND SN 0022-4251 J9 J REPROD FERTIL JI J. Reprod. Fertil. PD JUL PY 1999 VL 116 IS 2 BP 355 EP 361 PG 7 WC Reproductive Biology SC Reproductive Biology GA 214DB UT WOS:000081311400018 PM 10615261 ER PT J AU Jarzynski, C AF Jarzynski, C TI Microscopic analysis of Clausius-Duhem processes SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE irreversible processes ID FREE-ENERGY DIFFERENCES; NONEQUILIBRIUM MEASUREMENTS; STEADY-STATES AB Given a thermodynamic process which carries a system from one equilibrium state to another, we construct a quantity whose average, over an ensemble of microscopic realizations of the process, depends only on these end states, even if at intermediate times the system is our of equilibrium. This result (1) can be used to express the entropy difference between two equilibrium states in terms of an irreversible process connecting them, (2) leads to two statistical statements of the Clausius-Duhem inequality, and (3) can be generalized to situations in which the system begins and/or ends in nonequilibrium states. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Jarzynski, C (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-6 & T-13,MS B288, Los Alamos, NM 87545 USA. RI Jarzynski, Christopher/B-4490-2009 OI Jarzynski, Christopher/0000-0002-3464-2920 NR 11 TC 52 Z9 52 U1 2 U2 8 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD JUL PY 1999 VL 96 IS 1-2 BP 415 EP 427 DI 10.1023/A:1004541004050 PG 13 WC Physics, Mathematical SC Physics GA 235XZ UT WOS:000082570300016 ER PT J AU Hasnain, SS Hodgson, KO AF Hasnain, SS Hodgson, KO TI Structure of metal centres in proteins at subatomic resolution SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Review DE metalloproteins; superoxide dismutase; molybdenum enzymes; cupredoxins; MAD; EXAFS ID X-RAY-ABSORPTION; ERYTHROCYTE SUPEROXIDE-DISMUTASE; CURVED-WAVE THEORY; MOLECULAR ASSEMBLIES RELEVANT; MULTIPLE-SCATTERING ANALYSIS; FINE-STRUCTURE EXAFS; BLUE COPPER SITE; CRYSTAL-STRUCTURE; ANGSTROM RESOLUTION; ATOMIC-RESOLUTION AB Metalloproteins perform a wide variety of biological functions and, in doing so, in many cases exploit the redox properties and the coordination chemistry of the metal atom. The structural changes associated with the different coordination and redox changes can be quite small and can only be visualized at a very high resolution. The advent of synchrotron radiation has provided the possibility of studying these proteins by X-ray crystallography at 'atomic' resolutions. Synchrotron radiation has also revolutionized another X-ray technique, XAFS (X-ray absorption line structure), where modulations in atomic absorption take place due to the scattering of photo-excited electrons from the immediate surrounding of the photon-absorbing atom. The dependency of XAFS on synchrotron radiation is even more acute than protein crystallography, as a continuous X-ray spectrum of high intensity is required for the experiment. In fact, the source and monochomator requirements are very similar for XAFS and MAD (multiple-wavelength anamolous diffraction). The local nature of the XAFS has advantages in that no crystalline order is required and that the resolution is the same in the aqueous, amorphous or crystalline system, i.e. subatomic resolutions are intrinsically present in the data. This review written in recognition of Sir John Walker's Nobel prize, for which synchrotron radiation played a key role, also provides some recent case studies to illustrate the advantages of this technique and its synergy with the synchrotron-based crystallography. C1 CLRC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. SLAC, Stanford Synchrotron Radiat Lab, Stanford, CA USA. RP Hasnain, SS (reprint author), CLRC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. NR 118 TC 64 Z9 65 U1 0 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD JUL 1 PY 1999 VL 6 BP 852 EP 864 DI 10.1107/S0909049599006792 PN 4 PG 13 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 218MB UT WOS:000081555400007 ER PT J AU Russell, AM Ostenson, JE AF Russell, AM Ostenson, JE TI A low-temperature modification to the Charpy impact test, with an example study of the fracture toughness of Mg-12%Li between 4.2 to 77 K SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE fracture toughness; Charpy test; low temperature; magnesium-lithium alloy; ductile-brittle transition; impact strength AB A modification to the Charpy test for measuring impact fracture toughness has been developed that permits the specimen to be bathed in flowing liquid helium while mounted on the testing machine's anvil immediately prior to impact. This method permits samples to be tested at any temperature between 4.2 and 77 K, which extends the Charpy test to temperatures lower than those achievable by the conventional liquid bath immersion technique. A body-centered cubic Mg-12%Li single-phase alloy was tested by this new method and found to have anomalously high impact fracture toughness in the temperature range 4.2 to 77 K. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Russell, AM (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. OI Russell, Alan/0000-0001-5264-0104 NR 4 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD JUL PY 1999 VL 27 IS 4 BP 301 EP 303 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA 287YQ UT WOS:000085535400007 ER PT J AU Wang, M Saricks, C Wu, M AF Wang, M Saricks, C Wu, M TI Fuel ethanol produced from Midwest US corn: Help or hindrance to the vision of Kyoto? SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID NITROGEN; NITRATE; FIELD; SOIL AB In this study, we examined the role of corn-feedstock ethanol in reducing greenhouse gas (GHG) emissions, given present and near-future technology and practice for corn farming and ethanol production. We analyzed the full-fuel-cycle GHG effects of corn-based ethanol using updated information on corn operations in the upper Midwest and existing ethanol production technologies. Information was obtained from representatives of the U.S. Department of Agriculture, faculty of midwestern universities with expertise in tom production and animal feed, and acknowledged authorities in the held of ethanol plant engineering, design, and operations. Cases examined included use of E85 (85% ethanol and 15% gasoline by volume) and E10 (10% ethanol and 90% gasoline). Among key findings is that Midwest-produced ethanol outperforms conventional (current) and reformulated (future) gasoline with respect to energy use and GHG emissions (on a mass emission per travel mile basis). The superiority of the energy and GHG results is well outside the range of model "noise." An important facet of this work has been conducting sensitivity analyses. These analyses let us rank the factors in the corn-to-ethanol cycle that are most important for limiting GHG generation. These ran kings could help ensure that efforts to reduce that generation are targeted more effectively. C1 Argonne Natl Lab, Ctr Transportat Res, Argonne, IL 60439 USA. RP Wang, M (reprint author), Argonne Natl Lab, Ctr Transportat Res, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 46 TC 10 Z9 10 U1 2 U2 5 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD JUL PY 1999 VL 49 IS 7 BP 756 EP 772 PG 17 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 218ZR UT WOS:000081582900002 PM 28060657 ER PT J AU Doskey, PV Fukui, Y Sultan, M Al Maghraby, A Taher, A AF Doskey, PV Fukui, Y Sultan, M Al Maghraby, A Taher, A TI Source profiles for nonmethane organic compounds in the atmosphere of Cairo, Egypt SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID CHEMICAL MASS-BALANCE; SOURCE-RECONCILIATION; CALCULATED REACTIVITIES; SOURCE FINGERPRINTS; VOLATILE ORGANICS; AIR-QUALITY; EMISSIONS; HYDROCARBONS; OZONE; APPORTIONMENT AB Profiles of the sources of nonmethane organic compounds (NMOCs) were developed for emissions from vehicles, petroleum fuels (gasoline, liquefied petroleum gas [LPG], and natural gas), a petroleum refinery, a smelter and a cast iron factory in Cairo, Egypt. More than 100 hydrocarbons and oxygenated hydrocarbons were tentatively identified and quantified. Gasoline-vapor and whole-gasoline profiles could be distinguished from the other profiles by high concentrations of the C-5 and C-6 saturated hydrocarbons. The vehicle emission profile was similar to the whole-gasoline profile, with the exception of the unsaturated and aromatic hydrocarbons, which were present at higher concentrations in the vehicle emission profile. High levels of the C-2-C-4 saturated hydrocarbons, particularly n-butane, were characteristic features of the petroleum refinery emissions. The smelter and cast iron factory emissions were similar to the refinery emissions; however, the levels of benzene and toluene were greater in the former two sources. The LPG and natural gas emissions contained high concentrations of n-butane and ethane, respectively. The NMOC source profiles for Cairo were distinctly different from profiles for U.S. sources, indicating that NMOC source profiles are sensitive to the particular composition of petroleum fuels that are used in a location. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Cairo Univ, Ctr Environm Hazard Mitigat, Giza, Egypt. Cairo Univ, Dept Geol, Giza, Egypt. RP Doskey, PV (reprint author), Argonne Natl Lab, Div Environm Res, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 29 TC 22 Z9 23 U1 2 U2 6 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD JUL PY 1999 VL 49 IS 7 BP 814 EP 822 PG 9 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 218ZR UT WOS:000081582900007 PM 28060656 ER PT J AU de Souza, RE Schlenga, K Wong-Foy, A McDermott, R Pines, A Clarke, J AF de Souza, RE Schlenga, K Wong-Foy, A McDermott, R Pines, A Clarke, J TI NMR and MRI obtained with high transition temperature DC SQUIDs SO JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY LA English DT Article DE NMR; MRI; SQUID detected NMR ID QUANTUM INTERFERENCE DEVICE; NUCLEAR-MAGNETIC-RESONANCE; QUADRUPOLE RESONANCE; SAMPLES; SPECTROMETER; FREQUENCIES; SYSTEM AB We have measured nuclear magnetic resonance (NMR) signals from several samples at room temperature in magnetic fields ranging from about 0.05 mT to 2 mT using a spectrometer based on a high-T-c de SQUID (high transition temperature de Superconducting QUantum Interference Device). We are able to observe proton signals from 1 mL of mineral oil in 2 mT in a single transient. The sensitivity of this system has also allowed the detection of proton NMR at magnetic fields as low as 0.059 mT, which is comparable to the Earth's field. Such results make possible a number of new experiments in magnetic resonance imaging (MRI). We present a two-dimensional image of a phantom filled with mineral oil obtained in a field of 2 mT. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Fed Pernambuco, Dept Fis, BR-50670901 Recife, PE, Brazil. RP de Souza, RE (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 30 TC 11 Z9 11 U1 0 U2 3 PU SOC BRASILEIRA QUIMICA PI SAO PAULO PA CAIXA POSTAL 26037, 05599-970 SAO PAULO, BRAZIL SN 0103-5053 J9 J BRAZIL CHEM SOC JI J. Braz. Chem. Soc. PD JUL-AUG PY 1999 VL 10 IS 4 BP 307 EP 312 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 259BE UT WOS:000083873500009 ER PT J AU Fu, CL AF Fu, CL TI First principles calculations of structural and defect properties of high-temperature intermetallics SO JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS LA English DT Article DE first principles calculation; electronic structure; TiAl alloys; NiAl alloys; FeAl alloys; molybdenum silicides ID TRANSITION-METAL ALUMINIDES; POLYSYNTHETICALLY TWINNED CRYSTALS; INTERFACIAL ENERGIES; ELECTRONIC-STRUCTURE; LAMELLAR STRUCTURE; ELASTIC-CONSTANTS; FAULT ENERGIES; B2 STRUCTURE; FEAL; BEHAVIOR AB First principles quantum mechanical calculations based on the local-density-functional (LDF) theory have been used to investigate the electronic, structural, and defect properties of transition-metal aluminides and silicides. Three examples are given to show the predictive capability of modern LDF calculation: (1) interfacial properties of two-phase Ti-Al alloys, (2) point defect structure of NiAl and FeAl, and (3) elastic constants and coefficient of thermal expansion (CTE) of Mo5Si3. Emphasis is placed on the effect of interfaces on the planar fault energies in Ti-Al, the interaction between vacancies in B2 aluminides, and the interplay between bonding and the anisotropy in CTE in Mo5Si3. We show that first principles calculation not only yields results in excellent agreement with experiments (if available), but offers information on electronic structure from which a clearer understanding of atomic-level interactions that govern alloy behavior can be made. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Fu, CL (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 32 TC 0 Z9 0 U1 1 U2 4 PU CHINESE INST ENGINEERS PI TAIPEI PA #1, 4TH FL, SEC 2, JEN-AI RD, TAIPEI 10019, TAIWAN SN 0253-3839 EI 2158-7299 J9 J CHIN INST ENG JI J. Chin. Inst. Eng. PD JUL PY 1999 VL 22 IS 4 BP 457 EP 468 DI 10.1080/02533839.1999.9670484 PG 12 WC Engineering, Multidisciplinary SC Engineering GA 221RT UT WOS:000081740600008 ER PT J AU Giorgetti, M Passerini, S Smyrl, WH Mukerjee, S Yang, XQ McBreen, J AF Giorgetti, M Passerini, S Smyrl, WH Mukerjee, S Yang, XQ McBreen, J TI In situ X-ray absorption spectroscopy characterization of V2O5 xerogel cathodes upon lithium intercalation SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID VANADIUM PENTOXIDE GELS; NEAR-EDGE STRUCTURE; K-EDGE; ELECTROCHEMICAL CHARACTERIZATION; XAS; DIFFRACTION; ELECTRODE; AEROGELS; SPECTRA; HOSTS AB Vanadium pentoxide materials prepared through sol-gel processes act as excellent intercalation hosts for lithium as well as for polyvalent cations. Previous ex situ X-ray absorption spectroscopy and X-ray diffraction characterizations have shown that the electrochemical performance of vanadium pentoxide xerogels depends inversely on the long-range order of the V2O5-layered structure. Recently, new ways to prevent the self-organization of the dry materials, which takes place upon water removal from the starting hydrogel, have been introduced. In the present paper we report on the in situ X-ray absorption spectroscopy characterization of a spray-coated V2O5 (freeze-dried) xerogel cathode upon lithium intercalation. (C) 1999 The Electrochemical Society. S0013-4651(98)09-048-X. All rights reserved. C1 Univ Minnesota, Corros Res Ctr, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Brookhaven Natl Lab, Div Mat Sci, Dept Appl Sci, Upton, NY 11973 USA. RP Giorgetti, M (reprint author), Univ Minnesota, Corros Res Ctr, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. RI Passerini, Stefano/A-3859-2015; OI Passerini, Stefano/0000-0002-6606-5304; Giorgetti, Marco/0000-0001-7967-8364 NR 36 TC 76 Z9 78 U1 5 U2 27 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 JUL PY 1999 VL 146 IS 7 BP 2387 EP 2392 DI 10.1149/1.1391946 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 220EZ UT WOS:000081652700004 ER PT J AU Shao-Horn, Y Hackney, SA Armstrong, AR Bruce, PG Gitzendanner, R Johnson, CS Thackeray, MM AF Shao-Horn, Y Hackney, SA Armstrong, AR Bruce, PG Gitzendanner, R Johnson, CS Thackeray, MM TI Structural characterization of layered LiMnO2 electrodes by electron diffraction and lattice imaging SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID RECHARGEABLE LITHIUM BATTERIES; ORTHORHOMBIC LIMNO2; MANGANESE-DIOXIDE; CELLS; OXIDES; INTERCALATION; LIXCOO2; SYSTEM; TRANSFORMATION; CATHODE AB Electrode materials of the formula LiMnO2 were prepared by an ion-exchange process from alpha-NaMnO2 and were examined by X-ray diffraction and convergent-beam electron diffraction to determine crystal structure and phase purity. Electron diffraction data showed that a typical parent LiMnO2 sample consisted predominantly of layered LiMnO2 (C2/m) with lithiated-spinel Li-2[Mn-2]O-4 (F4(1)/ddm) present in minor concentration; orthorhombic LiMnO2 (Pmmm) was detected in trace quantity. An orientation relationship between the monoclinic layered LiMnO2 and tetragonal lithiated-spinel Li-2[Mn-2]O-4 was obtained from an analysis of single-crystal electron diffraction data. Electron diffraction analyses of three electrochemically cycled LixMnO2 (0 < x < 1) samples showed that the parent compound was unstable to repeated lithium intercalation/deintercalation and transformed to a spinel-type structure, consistent with previous reports. These LixMnO2 electrodes, like those derived from orthorhombic-LiMnO2, show greater stability compared to standard Li-y[Mn-2]O-4 spinel electrodes, when cycled between 4.6 and 2.0 V. The unexpected stability of the LixMnO2 electrodes (0.5 less than or equal to x < 1.0) at 3 V is attributed to the presence of Li1+zMn2-zO4 spinel domains (0 < z < 0.33) in a composite electrode structure. (C) 1999 The Electrochemical Society. S0013-4651(98)04-084-1. All rights reserved. C1 Michigan Technol Univ, Dept Met & Mat Engn, Houghton, MI 49931 USA. Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland. Argonne Natl Lab, Div Chem Technol, Electrochem Technol Program, Argonne, IL 60439 USA. RP Shao-Horn, Y (reprint author), Michigan Technol Univ, Dept Met & Mat Engn, Houghton, MI 49931 USA. NR 37 TC 123 Z9 126 U1 3 U2 88 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 JUL PY 1999 VL 146 IS 7 BP 2404 EP 2412 DI 10.1149/1.1391949 PG 9 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 220EZ UT WOS:000081652700007 ER PT J AU Hayes, SE Eckert, H Even, WR Guidotti, R AF Hayes, SE Eckert, H Even, WR Guidotti, R TI Structural and electrochemical characterization of glassy carbon prepared from silicon-doped polymethacrylonitrile/divinylbenzene copolymer SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID LITHIUM-ION BATTERIES; PITCH-POLYSILANE BLENDS; ANODE MATERIALS; INSERTION; POLYMERS AB There has been a great deal of discussion on the potential role of heteroatoms in carbons intended for lithium ion intercalation. Previous observations have been mixed, ranging from beneficial to detrimental effects on intercalation capacity, irreversible losses, and charge efficiencies. The introduction or substitution of silicon into a carbon matrix prepared by chemical vapor deposition has demonstrated a positive effect. The present study concerns substitutional effects in disordered carbons synthesized from polymer precursors. Solid-state nuclear magnetic resonance, photoacoustic IR spectroscopy, X-ray fluorescence, and high-resolution transmission electron microscopy were used to follow the modified carbon synthesis. Silicon is successfully incorporated into the polymer matrix by copolymerizing the precursors with tetravinylsilane. On oxidative stabilization and pyrolysis, however, the Si-C connectivity is replaced by Si-O coordination. These silicon species appear to be discrete, and no evidence for either a crystalline or amorphous secondary SiO2 phase is seen. These silicon species have a profound effect on the electrochemical performance. Irreversible loss processes are greatly increased, and charge efficiencies are decreased when compared to nonsubstituted controls. (C) 1999 The Electrochemical Society. S0013-4651(98)10-010-1. All rights reserved. C1 Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Hayes, SE (reprint author), Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. RI Hayes, Sophia/C-1075-2008; Eckert, Hellmut/G-3176-2012 OI Hayes, Sophia/0000-0002-2809-6193; NR 12 TC 8 Z9 8 U1 2 U2 7 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUL PY 1999 VL 146 IS 7 BP 2435 EP 2442 DI 10.1149/1.1391952 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 220EZ UT WOS:000081652700010 ER PT J AU Dudney, NJ Bates, JB Zuhr, RA Young, S Robertson, JD Jun, HP Hackney, SA AF Dudney, NJ Bates, JB Zuhr, RA Young, S Robertson, JD Jun, HP Hackney, SA TI Nanocrystalline LixMn2-yO4 cathodes for solid-state thin-film rechargeable lithium batteries SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID PHASE-DIAGRAM; LIMN2O4; SYSTEM; LI4MN5O12; CELL AB Thin-film cathodes of lithium manganese oxide, 0.3-3 mu m thick, were deposited by rf magnetron Sputtering of a LiMn2O4 ceramic target onto unheated substrates. The resulting films were dense, similar to 4.2 g/cm(3), with a similar to 50 Angstrom nanocrystalline spinel structure. The film composition was typically LixMn2-yO4 With y similar to 0.3 and 1.2 < x < 2.2. When cycled in a thin-film rechargeable lithium battery, specific cathode capacities of 145 +/- 23 and similar to 270 mAh/g were realized for discharge from 4.5 V to either 2.5 or 1.5 V,respectively. The discharge and charge current densities were limited by the resistivity of lithium transport into and through the cathode. After thousands of cycles at 25 degrees C, there was a small increase in cell resistance. After several hundred cycles at 100 degrees C, the discharge curves developed a stable knee at similar to 4 V characteristic of crystalline LiMn2O4 cathodes. The polarization of the discharge/charge cycles were interpreted in terms of free energy of mixing curves. (C) 1999 The Electrochemical Society. S0013-4651(98)11-060-1. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Kentucky, Dept Chem, Lexington, KY 40506 USA. Michigan Technol Univ, Dept Met & Mat Engn, Houghton, MI 49931 USA. RP Dudney, NJ (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Dudney, Nancy/I-6361-2016 OI Dudney, Nancy/0000-0001-7729-6178 NR 31 TC 112 Z9 120 U1 4 U2 50 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 JUL PY 1999 VL 146 IS 7 BP 2455 EP 2464 DI 10.1149/1.1391955 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 220EZ UT WOS:000081652700013 ER PT J AU Han, JH Shin, MC Kang, SH AF Han, JH Shin, MC Kang, SH TI Effect of grain structure on the current-density exponent in the black equation for Al-alloy interconnects SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Electronic Materials CY AUG 24-27, 1998 CL CHEJU, SOUTH KOREA ID ELECTROMIGRATION; FAILURE; LIFETIMES; MODEL; LINES AB Lifetimes of Al-based interconnects against electromigration-induced failures have been predicted by a well-known empirical relation (Black equation). The numerical value of the current-density exponent (n) contained in the Black equation has commonly been accepted as 2. However, the n value often deviates from 2, depending on the interconnect geometry or the applied current density. The work reported here shows that n also varies as a function of the microstructure. We have explored the Black equation over a wide range of interconnect grain structures. As they evolve from homogeneous polygranular lines to "quasi-bamboo" lines and eventually to almost perfect "bamboo" lines, the n value increases from 1.9 to 2.4 and finally to 3.1, respectively. The significance of the experimental results is discussed based on the microstructural mechanisms of electromigration failures. C1 KIST, Div Met, Seoul 136791, South Korea. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Han, JH (reprint author), KIST, Div Met, Seoul 136791, South Korea. NR 11 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 JUL PY 1999 VL 35 SU S BP S256 EP S259 PN 2 PG 4 WC Physics, Multidisciplinary SC Physics GA 223EM UT WOS:000081827900049 ER PT J AU Kang, SH Morris, JW AF Kang, SH Morris, JW TI The use of metallurgy in designing highly reliable microelectronic interconnects SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Electronic Materials CY AUG 24-27, 1998 CL CHEJU, SOUTH KOREA ID THIN-FILM INTERCONNECTS; ELECTROMIGRATION FAILURE; CONDUCTING LINES AB The reliability of an integrated circuit is often limited by electromigration-induced failure in thin-film interconnects. This article demonstrates how modifying the microstructure can inhibit the failure of Al-alloy interconnects that have quasi-bamboo microstructures. The microstructural mechanism of the failure is presented along with a constitutive equation that determines the failure kinetics. Useful metallurgical techniques, which can improve the reliability by modulating the failure kinetics, are discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. RP Kang, SH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. NR 10 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 JUL PY 1999 VL 35 SU S BP S260 EP S263 PN 2 PG 4 WC Physics, Multidisciplinary SC Physics GA 223EM UT WOS:000081827900050 ER PT J AU Lee, GD Wang, CZ Lu, ZY Ho, KM AF Lee, GD Wang, CZ Lu, ZY Ho, KM TI Addimer diffusions on Si(100) SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT Symposium 99 on Theoretical Solid State Physics CY JAN 25-27, 1999 CL TAEJON, SOUTH KOREA ID SI AD-DIMERS; SCANNING-TUNNELING-MICROSCOPY; SI(001); SURFACE; DYNAMICS; TEMPERATURE; NUCLEATION; BINDING; SILICON; GROWTH AB The diffusion pathways along the trough and between the trough and the 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. The calculated energy barriers are in excellent agreement with experiment. The rotaional diffusion pathway between the trough and the dimer row is much pathways by parallel and perpendicular addimer. as the energy barrier of the diffusion pathway by more energetically favorable than other diffusion The new pathway along the trough is nearly same dissociation of the addimer. C1 Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. US Dept Energy, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Lee, GD (reprint author), Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. RI Lee, Gun-Do/L-1259-2013 OI Lee, Gun-Do/0000-0001-8328-8625 NR 22 TC 1 Z9 1 U1 1 U2 2 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 JUL PY 1999 VL 35 SU S BP S27 EP S34 PN 1 PG 8 WC Physics, Multidisciplinary SC Physics GA 218UP UT WOS:000081570800006 ER PT J AU Morris, JW AF Morris, JW TI The microstructure and properties of solder joints SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Electronic Materials CY AUG 24-27, 1998 CL CHEJU, SOUTH KOREA AB Solder joints in microelectronic devices consist of low-melting alloys that wet and join metal contacts and are, ordinarily, used at high homologous temperatures in the as-solidified condition. Differences in solidification rate and substrate interactions have the consequence that even solder joints of similar composition exhibit a wide range of microstructures. The different microstructures have different properties; for this reason, the high-temperature creep properties that govern much of the mechanical behavior of the solder may differ significantly from joint to joint. The modern trend toward ultrafine-pitch solder joints raises new questions as the joints take on dimensions that are commensurate with the scale of the microstructure and the dimensions of common interfacial flaws. C1 Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA USA. RP Morris, JW (reprint author), Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. NR 9 TC 2 Z9 2 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 JUL PY 1999 VL 35 SU S BP S335 EP S339 PN 2 PG 5 WC Physics, Multidisciplinary SC Physics GA 223EM UT WOS:000081827900069 ER PT J AU Dowding, KJ Beck, JV Blackwell, BF AF Dowding, KJ Beck, JV Blackwell, BF TI Estimating temperature-dependent thermal properties SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA/ASME 7th Joint Thermophysics and Heat Transfer Conference CY JUN 15-18, 1998 CL ALBUQUERQUE, NEW MEXICO SP AIAA, ASME ID CARBON-CARBON COMPOSITE; HEAT-CAPACITY; CONDUCTIVITY AB Parameter estimation techniques are applied to estimate temperature-dependent thermal properties from a series of transient experiments. Several experiments with one- and two-dimensional heat flow that cover a range from room temperature to 500 degrees C are analyzed. Temperature dependent thermal properties are estimated by connecting the independent experiments in the series during the analysis. The techniques are applied to estimate effective properties of carbon carbon composite. The temperature dependence of two components of thermal conductivity and volumetric heat capacity are estimated to characterize the assumed orthotropic material. The techniques can be equally applied to other homogenous materials. Combining experiments during the analysis is referred to as a sequential analysis, which uses the concepts of regularization and prior information. Regularization controls variations in the estimated parameters. Prior information carries information from a previous analysis into a subsequent analysis. The functional dependence of the properties estimated with a sequential analysis show excellent agreement with previous analyses that considered the experiments independently. C1 Sandia Natl Labs, Thermal Sci Dept 9113, Albuquerque, NM 87185 USA. Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. RP Dowding, KJ (reprint author), Sandia Natl Labs, Thermal Sci Dept 9113, POB 5800, Albuquerque, NM 87185 USA. NR 18 TC 15 Z9 15 U1 0 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1999 VL 13 IS 3 BP 328 EP 336 DI 10.2514/2.6463 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 216VA UT WOS:000081464100009 ER PT J AU Cao, XA Ren, F Pearton, SJ Zeitouny, A Eizenberg, M Zolper, JC Abernathy, CR Han, J Shul, RJ Lothian, JR AF Cao, XA Ren, F Pearton, SJ Zeitouny, A Eizenberg, M Zolper, JC Abernathy, CR Han, J Shul, RJ Lothian, JR TI W and WSix Ohmic contacts on p- and n-type GaN SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID ELECTRICAL-PROPERTIES; THERMAL-STABILITY; TEMPERATURE; NITRIDE; GROWTH; FILMS AB W and WSi Ohmic contacts on both p- and n-type GaN have been annealed at temperatures from 300 to 1000 degrees C. There is minimal reaction (less than or equal to 100 Angstrom broadening of the metal/GaN interface) even at 1000 degrees C. Specific contact resistances in the 10(-5) Ohm cm(2) range are obtained for WSi, on Si-implanted GaN with a peak doping concentration of similar to 5 x 10(20) cm(-3), after annealing at 950 degrees C. On p-GaN, leaky Schottky diode behavior is observed for W, WSix and Ni/Au contacts at room temperature, but true Ohmic characteristics are obtained at 250-300 degrees C, where the specific contact resistances are, typically, in the 10(-2) Ohm cm(2) range. The best contacts for W and WSix are obtained after 700 degrees C annealing for periods of 30-120 s. The formation of beta-W2N interfacial phases appear to be important in determining the contact quality. (C) 1999 American Vacuum Society. [S0734-2101(99)00204-3]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Technion Israel Inst Technol, Dept Mat Engn, IL-32000 Haifa, Israel. Off Naval Res, Arlington, VA 22217 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Cao, XA (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 26 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1221 EP 1225 DI 10.1116/1.581799 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700026 ER PT J AU Wilson, RG Zavada, JM Cao, XA Singh, RK Pearton, SJ Guo, HJ Pennycock, SJ Fu, M Sekhar, JA Scarvepalli, V Shu, RJ Han, J Rieger, DJ Zolper, JC Abernathy, CR AF Wilson, RG Zavada, JM Cao, XA Singh, RK Pearton, SJ Guo, HJ Pennycock, SJ Fu, M Sekhar, JA Scarvepalli, V Shu, RJ Han, J Rieger, DJ Zolper, JC Abernathy, CR TI Redistribution and activation of implanted S, Se, Te, Be, Mg, and C in GaN SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID ION-IMPLANTATION; TEMPERATURE; DEFECTS AB A variety of different possible donor and acceptor impurities have been implanted into GaN and annealed up to 1450 degrees C. S+ and Te+ produce peak electron concentrations less than or equal to 5 X 10(18) cm(-3), well below that achievable with Si+. Mg produces p-type conductivity, but Be+- and C+- implanted samples remained n type. No redistribution was observed for any of the implanted species for 1450 degrees C annealing. Much more effective damage removal was achieved for 1400 degrees C annealing of high-dose (5 X 10(15) cm(-2)) Si+ implanted GaN, compared to the more commonly used 1100 degrees C annealing. (C) 1999 American Vacuum Society. [S0734-2101(99)01404-9]. C1 USA, Res Off, Res Triangle Pk, NC 27709 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Micropyret Heaters Int Inc, Cincinnati, OH 45215 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Off Naval Res, Arlington, VA 22217 USA. NR 23 TC 9 Z9 9 U1 3 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1226 EP 1229 DI 10.1116/1.581800 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700027 ER PT J AU Chen, XD Gibson, JM AF Chen, XD Gibson, JM TI Roughness at Si/SiO2 interfaces and silicon oxidation SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID GROWTH; KINETICS; STEPS; FILMS AB With a plan-view transmission electron microscopy technique of directly imaging buried Si/SiO2 interfaces, we studied the interface roughness resulting from the oxidation process. Our results show that thermal annealing in nitrogen at 900 degrees C can dramatically remove the interface roughness for Si(100)/SiO2 interfaces [X. Chen and J. M. Gibson, Appl. Phys. Lett. 70, 1462 (1997)]. In contrast, Si(111)/SiO2 interfaces,which tend to be smoother than Si(100)/SiO2 interfaces, are not affected by annealing. A model to link interface roughness and silicon oxidation kinetics was developed. This model not only qualitatively explains the difference between Si(111) and Si(100) interfaces that we saw but also shows that oxidation dynamics is the origin of the interface roughness. Hence, it might be a new approach to understand oxidation dynamics through studying interface roughness. (C) 1999 American Vacuum Society. [S0734-2101(99)06304-6]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Chen, XD (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Gibson, Murray/E-5855-2013 OI Gibson, Murray/0000-0002-0807-6224 NR 21 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1269 EP 1274 DI 10.1116/1.581807 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700035 ER PT J AU Mishra, SR Cummins, TR Waddill, GD Gammon, WJ van der Laan, G Goodman, KW Tobin, JG AF Mishra, SR Cummins, TR Waddill, GD Gammon, WJ van der Laan, G Goodman, KW Tobin, JG TI Investigation of resonant photoemission in Gd with x-ray linear dichroism SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID MAGNETIC CIRCULAR-DICHROISM; CORE-LEVEL PHOTOEMISSION; 4F PHOTOEMISSION; ULTRATHIN FILMS; ALLOY-FILMS; METAL; FE; GD(0001)/W(110); PHOTOABSORPTION; PHOTOELECTRONS AB The constructive summing of direct and indirect channels above the absorption threshold of a core level can cause a massive increase in the emission cross section, leading to a phenomenon called "resonant photoemission." Using novel magnetic linear dichroism in angular distribution photoelectron spectroscopy experiments and theoretical simulations, we have probed the nature of the resonant photoemission process in Gd metal. It now appears that temporal matching as well as energy matching is a requirement for true resonant photoemission. (C) 1999 American Vacuum Society. [S0734-2101(99)10004-6]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. Univ Missouri, Dept Phys, Rolla, MO 65401 USA. SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RP Tobin, JG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Tobin, James/O-6953-2015; van der Laan, Gerrit/Q-1662-2015 OI van der Laan, Gerrit/0000-0001-6852-2495 NR 49 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 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1313 EP 1318 DI 10.1116/1.581812 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700043 ER PT J AU Hochstrasser, M Schumann, FO Willis, RF Cummins, T Waddill, GD Mishra, SR Tobin, JG Rotenberg, E AF Hochstrasser, M Schumann, FO Willis, RF Cummins, T Waddill, GD Mishra, SR Tobin, JG Rotenberg, E TI Fermi surface study of pseudomorphic Fe1-xNix and Co1-xNix thin films on Cu(100) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID CU-NI; PHOTOEMISSION; INSTABILITY; ALLOYS; GROWTH; LEVEL AB We report angle resolved photoemission studies of the electronic behavior of ultrathin epitaxial layers of fcc structured binary alloys, Fe1-xNix and Co1-xNix, deposited by molecular beam epitaxy on Cu(100) substrates. In particular, we have used Fermi surface mapping to monitor changes in the Fermi surface with increasing magnetization density. Fe1-xNix and Co1-xNix binary alloys show a different behavior in the bulk. Co1-xNix is structurally and magnetically well-behaved. In particular, the magnetic moment varies linearly as a function of concentration. This is in sharp contrast to fcc Fe1-xNix which displays a magnetic instability at similar to 65% Fe content. An, extended regime of fcc stability is possible via epitaxy on Cu(100). The changes in the Fermi surfaces of Fe1-xNix and Co1-xNix pseudomorphic film alloys depending on various concentrations of Ni have been investigated in a large photon energy regime. We address the following question: To what degree is the Fermi surface sharply preserved in substitutional alloys? (C) 1999 American Vacuum Society. [S0734-2101(99)01004-0]. C1 Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Missouri, Rolla, MO 65401 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA USA. RP Hochstrasser, M (reprint author), Penn State Univ, Dept Phys, University Pk, PA 16802 USA. RI Rotenberg, Eli/B-3700-2009; Schumann, Frank /K-9364-2014; Tobin, James/O-6953-2015 OI Rotenberg, Eli/0000-0002-3979-8844; NR 14 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 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1322 EP 1325 DI 10.1116/1.581814 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700045 ER PT J AU Tobin, KW Karnowski, TP Gleason, SS Jensen, D Lakhani, F AF Tobin, KW Karnowski, TP Gleason, SS Jensen, D Lakhani, F TI Using historical wafermap data for automated yield analysis SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID DEFECT CLASSIFICATION AB To be productive and profitable in a modern semiconductor fabrication environment, large amounts of manufacturing data must be collected, analyzed, and maintained. This includes data collected from in- and off-line wafer inspection systems and from the process equipment itself. This data is increasingly being used to design new processes, control and maintain tools, and to provide the information needed for rapid yield learning and prediction. Because of increasing device complexity, the amount of data being generated is outstripping the yield engineer's ability to effectively monitor and correct unexpected trends and excursions. The 1997 SIA National Technology Roadmap for Semiconductors highlights a need to address these issues through "automated data reduction algorithms to source defects from multiple data sources and to reduce defect sourcing time." SEMATECH and the Oak Ridge National Laboratory have been developing new strategies and technologies for providing the yield engineer with higher levels of assisted data reduction for the purpose of automated yield analysis. In this article, we will discuss the current state of the art and trends in yield management automation. (C) 1999 American Vacuum Society. [S0734-2101(99)04404-8]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. SEMATECH, Austin, TX 78741 USA. RP Tobin, KW (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Escarabajal, Juan Antonio/C-5644-2012 NR 27 TC 3 Z9 3 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1369 EP 1376 DI 10.1116/1.581822 PN 1 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700053 ER PT J AU Hanson, DE Kress, JD Voter, AF AF Hanson, DE Kress, JD Voter, AF TI Reactive ion etching of Si by Cl and Cl-2 ions: Molecular dynamics simulations with comparisons to experiment SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID INDUCED THERMAL-DESORPTION; DIMERIZED SI(100) SURFACE; COMPUTER-SIMULATION; SILICON; CHLORINE; FLUORINE; CHEMISORPTION; CHEMISTRY; LAYER AB We present results of molecular dynamics simulations of reactive ion etching (RIE) of a reconstructed Si(100)(2x1) surface. The existing Stillinger-Weber interatomic potential for Si/Cl of Fell ed al. has been modified by correcting the Si-Si bond strength for a SiCln moiety bound to a Si surface and the Si-Cl bond strength in SiClm molecules. This potential has been used to study RTE of Si by Gland Cl-2 ions. The calculated properties such as the Si yield, product stoichiometry, stoichiometry of the chlorosilyl surface, and Cl content of the chlorosilyl layer are in reasonable agreement with experiment. The dissociative chemisorption probability of Cl-2 on Si(100)(2X1) as a function of energy has been simulated and the results are in reasonable agreement with experiment. (C) 1999 American Vacuum Society. [S0734-2101(99)06104-7]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hanson, DE (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 39 TC 14 Z9 14 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1510 EP 1513 DI 10.1116/1.581844 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700077 ER PT J AU Jayaraman, R McGrath, RT Hebner, GA AF Jayaraman, R McGrath, RT Hebner, GA TI Ion and neutral species in C2F6 and CHF3 dielectric etch discharges SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID COUPLED CHLORINE PLASMAS; ELECTRON-IMPACT; DENSITY AB Relative concentrations of reactive ions, neutral radicals, resist and substrate etch products have been measured in dielectric etch chemistries using an uncollided beam mass spectrometer/ion extractor from Hiden Analytical. Analysis techniques employed include both electron impact ionization and dissociative ionization of neutral gas, and potential bias extraction of positive ions from the reactor discharge volume. Measurements were made in C2F6 and CHF3 discharges in an inductively coupled plasma (GEC) research reactor operating with power densities, pressures, gas compositions and wafer materials typical of those found in etch processing tools. Wafer substrates investigated included blanket silicon wafers and silicon wafers with varying amounts of photoresist coverage of the surface (20%, 80% and 100%). In C2F6 discharges CF3+ was consistently the dominant fluorocarbon ion present, in agreement with published cross sections for dissociative ionization. Smaller concentrations of CF+, CF2+, and C2F5+, were also observed, though the dissociative ionization production of C2F5+ was a factor of 5 smaller than would be expected from published cross section values. The presence of photoresist, even in small amounts, was found to produce marked changes in the discharge composition. For example, in C2F6 discharges, concentrations of SiFx etch products relative to concentrations of CxFy species were notably diminished and larger concentrations of water vapor were observed when resist was present. In CHF3 discharges, CF3+ and CHF2+ were found to be the main species present, along with smaller concentrations of CF2+, CF+, CHF+, CH+ and F+. (C) 1999 American Vacuum Society. [S0734-2101(99)13704-7]. C1 Penn State Univ, University Pk, PA 16802 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Jayaraman, R (reprint author), Penn State Univ, University Pk, PA 16802 USA. NR 19 TC 33 Z9 33 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1545 EP 1551 DI 10.1116/1.581850 PN 1 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700084 ER PT J AU Yi, SI Liang, Y Chambers, SA AF Yi, SI Liang, Y Chambers, SA TI Effect of growth rate on the nucleation of alpha-Fe2O3 on alpha-Al2O3(0001) by oxygen-plasma-assisted molecular beam epitaxy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID FILMS; SURFACES; IRON AB We have investigated the role of growth rate on the nucleation of epitaxial alpha-Fe2O3 on alpha-Al2O3(0001). We show that a slow growth rate (similar to 1-2 Angstrom/min) must be employed during growth of the first 30 Angstrom in order to form relaxed, three-dimensional islands. A higher growth rate (similar to 0.1-0.3 Angstrom/s) can then be used. Island coalescence occurs, resulting in a laminar surface for film thicknesses as low as a few hundred Angstrom. If a higher initial growth rate is used, three-dimensional island growth is kinetically impeded, and film relaxation occurs by misfit dislocation generation. The film surface then roughens on a more macroscopic length scale, giving rise to a poor quality surface; (C) 1999 American Vacuum Society. [S0734-2101(99)20604-5]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99325 USA. RP Yi, SI (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99325 USA. NR 15 TC 9 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1737 EP 1742 DI 10.1116/1.581883 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700120 ER PT J AU Moutinho, HR Dhere, RG Al-Jassim, MM Levi, DH Kazmerski, LL AF Moutinho, HR Dhere, RG Al-Jassim, MM Levi, DH Kazmerski, LL TI Investigation of induced recrystallization and stress in close-spaced sublimated and radio-frequency magnetron sputtered CdTe thin films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc AB We have induced recrystallization of small grain CdTe thin films deposited at low temperatures by close-spaced sublimation (CSS), using a standard CdCl2 annealing treatment. We also studied the changes in the physical properties of CdTe films deposited by radio-frequency magnetron Sputtering after the same post-deposition processing. We demonstrated that the effects of CdCl2 on the physical properties of CdTe films are similar, and independent of the deposition. method. The recrystallization process is linked directly to the grain size and stress in the films. These studies indicated the feasibility of using lower-temperature processes in fabricating efficient CSS CdTe solar cells. We believe that, after the optimization of the parameters of the chemical treatment, these films can attain a quality similar to CSS films grown using current standard conditions. (C) 1999 American Vacuum Society. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Moutinho, HR (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 11 TC 53 Z9 56 U1 1 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1793 EP 1798 DI 10.1116/1.581892 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800006 ER PT J AU Gao, Y Mueller, AH Irene, EA Auciello, O Krauss, A Schultz, JA AF Gao, Y Mueller, AH Irene, EA Auciello, O Krauss, A Schultz, JA TI In situ study of interface reactions of ion beam sputter deposited (Ba0.5Sr0.5)TiO3 films on Si, SiO2, and Ir SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID ACCESS MEMORY APPLICATION; (BA,SR)TIO3 THIN-FILMS; SPECTROSCOPIC ELLIPSOMETRY; OPTICAL-PROPERTIES; MICROELECTRONICS; TITANATE AB (Ba0.5Sr0.5)TiO3 (BST) thin films were deposited on MgO, Si, SiO2 and Ir surfaces by ion: beam sputter deposition in oxygen at 700 degrees C. In situ spectroscopic ellipsometry (SE) has been used to investigate the evolution of the BST films on different surfaces-during both deposition and postannealing processes; First, the optical constants of the BST films in the photon energy range of 1.5-4.5 eV were determined by SE analysis on crystallized BST films;deposited on MgO single crystal substrates, The interfaces in BST/Si and BST/SiO2/Si structure were examined by SE and Auger electron spectroscopy depth profiles. Subcutaneous oxidation in the BST/Ir structure was:: observed by in situ SE during both ion beam sputter deposition and postdeposition annealing in oxygen at 700 degrees C. A study of the thermal stability of the Ir/TiN/SiO2/Si structure in oxygen at 700 degrees C was carried out using in situ SE. The oxidation of Ir was confirmed by x-ray diffraction. The surface composition and morphology evolution after oxidation were investigated by time of flight mass spectroscopy of recoiled ions (TOF-MSRI) and atomic force microscopy. It has been found that Ti from the underlying TiN barrier layer diffused through-the Ir layer onto the surface and thereupon became oxidized. It was also shown that the surface roughness increases with increasing oxidation time. The implications of the instability of Ir/TiN/SiO2/Si structure on the performance of capacitor; devices based on this substrate are discussed. It has been, shown that a combination of in situ SE and TOF-MSRI provides a powerful methodology for in situ monitoring of complex oxide film growth and postannealing processes. (C) 1999 American Vacuum Society. [S0734-2101(99)17604-8]. C1 Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Ionwerks Inc, Houston, TX 77005 USA. RP Gao, Y (reprint author), Univ N Carolina, Dept Chem, CB 3290, Chapel Hill, NC 27599 USA. NR 23 TC 40 Z9 41 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1880 EP 1886 DI 10.1116/1.582099 PN 2 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800022 ER PT J AU Carey, PG Smith, PM Theiss, SD Wickboldt, P AF Carey, PG Smith, PM Theiss, SD Wickboldt, P TI Polysilicon thin film transistors fabricated on low temperature plastic substrates SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID TFTS; DISPLAYS; GLASS; CVD AB we present device results from polysilicon thin film transistors (TFTs) fabricated at a maximum temperature of 100 degrees C on polyester substrates. Critical to our success has been the development off a processing cluster tool containing chambers dedicated to laser crystallization, dopant deposition, and gate oxidation. Our TFT fabrication process integrates multiple steps in this tool, and uses the laser to crystallize deposited amorphous silicon as well as create heavily doped TFT source/drain regions. By combining laser crystallization and-doping, a plasma enhanced chemical vapor deposition SiO2 layer for the gate dielectric, and postfabrication annealing at 150 degrees C, We have succeeded in fabricating TFTs with I-ON/I-OFF ratios >5 X 10(5) and electron mobilities >40 cm(2)/Vs on polyester substrates. (C) 1999 American Vacuum Society. [S0734-2101(99)16304-8]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Carey, PG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-271, Livermore, CA 94551 USA. NR 9 TC 80 Z9 82 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1946 EP 1949 DI 10.1116/1.581708 PN 2 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800032 ER PT J AU Affinito, JD Gross, ME Mounier, PA Shi, MK Graff, GL AF Affinito, JD Gross, ME Mounier, PA Shi, MK Graff, GL TI Ultrahigh rate, wide area, plasma polymerized films from high molecular weight low vapor pressure liquid or solid monomer precursors SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID DEPOSITION AB A new process has been developed for the high rate vacuum deposition of solid films from high molecular weight/low vapor pressure liquid, or even solid,monomer precursors. The gas resulting from the flash evaporation of a liquid monomer mixture or from a suspension of liquid monomer and, insoluble solid particles is used as the support medium for a glow discharge in a plasma enhanced chemical Gaper deposition-like process. Due to the high molecular weight/low vapor pressure nature of the precursors, the plasma of the flash evaporated gas cryocondenses at an extremely high rate on substrates at ambient, and higher, temperatures. Upon condensation the liquefied plasma immediately begins to polymerize to form a solid film due to the high concentration of radicals and ions contained in the liquid film. The process has been successfully implemented,in, a vacuum roll coating system in a roll-to-roll deposition process. Polymer films and molecularly doped polymer composite films of polymer and light emitting organic molecules have, been deposited at thicknesses ranging from about 0.1 to 24 mu m at web speeds between 96 and 0.5 linear meters per minute. This new deposition process will be discussed along with some properties of the films fabricated with this new process. (C) 1999 American Vacuum Society. [S0734-2101(99)09704-3]. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Affinito, JD (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 9 TC 18 Z9 18 U1 3 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1974 EP 1981 DI 10.1116/1.581713 PN 2 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800037 ER PT J AU Dong, CK Myneni, GR AF Dong, CK Myneni, GR TI Field emitter based extractor gauges and residual gas analyzers SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID COLD-CATHODE; EMISSION; VACUUM AB Attempts at using the Spindt-type molybdenum held emitter arrays in the extractor gauges and a residual gas analyzer are presented in this article. The sensitivity of the field emitter gauge is as high as 11 Torr(-1). The departure from linearity of the pressure versus ion current measurements did not exceed 10% over the pressure range of 10(-10)-10(-6) Torr. Stable sensitivities for nitrogen, helium, and hydrogen were achieved below 10(-7) Torr with the field emitter residual gas analyzer. The slightly reduced emission current and sensitivity, after long-term operation, are of concern and need to be addressed. Residual gas spectra indicate that when using field emitters; the electron stimulated desorption ions (O+, F+, and Cl+) are reduced as compared to those made using a hot filament source. (C) 1999 American Vacuum Society. [S0734-2101(99)18004-7]. C1 Thomas Jefferson Natl Accelerator Facil, Accelerator Dev, Newport News, VA 23606 USA. Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. RP Dong, CK (reprint author), Thomas Jefferson Natl Accelerator Facil, Accelerator Dev, Newport News, VA 23606 USA. NR 14 TC 10 Z9 12 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2026 EP 2033 DI 10.1116/1.581722 PN 2 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800046 ER PT J AU Chao, EH Paul, SF Davidson, RC AF Chao, EH Paul, SF Davidson, RC TI Dynamics of the m=1 diocotron mode in the electron diffusion gauge experiment SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID BACKGROUND NEUTRAL GAS; FINITE-LENGTH; ELASTIC COLLISIONS; PLASMA; WAVES; INSTABILITY; EXPANSION AB The evolution of-the m = 1 dicotron mode is studied experimentally over a wide range of system parameters for a pure electron plasma confined in a Malmberg-Penning trap. The frequency of the m = 1 diocotron mode is monitored and found to be higher than that predicted by Levy [Phys. Fluids 11, 920 (1968)] for an infinite-length plasma column. However, the experimental measurements,of the m = 1 mode frequency reported here are found to be in excellent agreement with the theoretical predictions for a finite-length plasma column. The growth and damping rates of the m = 1 diocotron: mode are also carefully measured and compared with theoretical predictions. Probably the strongest factor affecting the stability of the m = 1 diocotron mode in a, nonneutral plasma with a monotonically decreasing radial density profile is resistive-wall destabilization. The measured resistive growth rates are found to agree with theory, at least for moderate values of resistance. Even after minimizing the resistive-wall instability, and maintaining the background gas:pressure sufficiently low that pressure effects on the m = 1 diocotron mode are negligible, it is observed experimentally that there is an "anomalous"damping of the m = 1 diocotron mode that depends on the magnetic field, B, and the line density, N-L, through the ratio N-L/B, which is proportional to the oscillation frequency of the m = 1 diocotron mode. Although the cause of this damping is not understood from first principles, its effects can be minimized by tuning the frequency of the diocotron mode. Finally, although electron collisions with background neutral atoms had been expected to result in an unstable m = 1 diocotron mode, it was observed that increasing the background gas pressure causes a damping of the m = 1 mode. (C) 1999 American Vacuum Society. [S0734-2101(99)11104-7]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Chao, EH (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 19 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2034 EP 2040 DI 10.1116/1.581723 PN 2 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800047 ER PT J AU Chao, EH Davidson, RC Paul, SF AF Chao, EH Davidson, RC Paul, SF TI Non-neutral plasma expansion induced by electron-neutral collisions in a Malmberg-Penning trap SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID ELASTIC COLLISIONS; TRANSPORT; POSITRON; RELAXATION; PARTICLE; CATHODE; GAS AB Single species non-neutral plasmas have very robust confinement properties because the conservation of canonical angular momentum in a system with azimuthal symmetry provides, a powerful constraint on the allowed radial positions of the particles. If no external torques act on the plasma the plasma cannot expand radially to the wall. However, collisions with a background neutral gas will exert a torque on the rotating plasma thus allowing the mean-square radius to increase. In the electron diffusion gauge experiment, a pure electron plasma is confined in a Malmberg-Penning trap and the radial density profile is measured as a function of time. The base pressure is 5 x 10(-10) Torr and purified helium is injected to pressures greater than or equal to 5 x 10(-9) Torr. The magnetic field is varied between 100 and 600 G. The experimentally measured radial density profile shape is found to match closely the theoretically predicted (expanding) equilibrium profile, where a single free parameter proportional to the electron temperature T-is varied to best fit the experimental data. The best-fit value of the temperature T is found to stay approximately constant:;even as the plasma expands and the electrostatic energy decreases. The measured plasma expansion rate is found to scale with magnetic field strength as 1/B-3/2 instead of the expected 1/B-2 scaling. This modification in scaling may be caused by field asymmetries; which are believed to be an important factor in plasma expansion for the pressure ranges examined here. Nevertheless, the expansion rates are observed to increase with increasing background pressure, and: the absolute scaling with pressure is consistent with theoretical predictions, (C) 1999 American Vacuum Society, [S0734-2101(99)16604-1]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Chao, EH (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 21 TC 13 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2050 EP 2055 DI 10.1116/1.581724 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800049 ER PT J AU Albin, S Fu, W Varghese, A Lavarias, AC Myneni, GR AF Albin, S Fu, W Varghese, A Lavarias, AC Myneni, GR TI Diamond coated silicon field emitter array SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID CHEMICAL-VAPOR-DEPOSITION; EMISSION PROPERTIES; TIPS; FABRICATION; FILMS AB Diamond coated silicon tip arrays, with and without a self-aligned gate, were fabricated, and current-voltage characteristics of 400 tips were measured. Diamond films were grown uniformly on Si tips using microwave plasma after nucleation with 10 nm diamond Suspension and substrate bias. An emission current of 57 mu A was obtained at 5 V from the ungated array tips separated from an anode at 2 mu m. In the case of the gated arrays with 1.5 mu m aperture; an emission current of 3.4 mu A was measured at a gate voltage of 80 V for an anode separation of 200 mu m. The turn-on voltages for these two types of devices were 0.2 and 40 V, respectively; Diamond coated-Si tip arrays have potential applications in field emission based low voltage vacuum electronic devices and microsensors. (C) 1999 American Vacuum Society. [S0734-2101(99)05804-2]. C1 Old Dominion Univ, Microelect Res Lab, Norfolk, VA 23529 USA. Thomas Jefferson Natl Accelerator Facil, Accelerator Dev, Newport News, VA 23606 USA. RP Albin, S (reprint author), Old Dominion Univ, Microelect Res Lab, Norfolk, VA 23529 USA. NR 16 TC 6 Z9 7 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2104 EP 2108 DI 10.1116/1.581733 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800059 ER PT J AU Dylla, HF Biallas, G Dillon-Townes, LA Feldl, E Myneni, GR Parkinson, J Preble, J Siggins, T Williams, S Wiseman, M AF Dylla, HF Biallas, G Dillon-Townes, LA Feldl, E Myneni, GR Parkinson, J Preble, J Siggins, T Williams, S Wiseman, M TI Design and installation of a low particulate, ultrahigh vacuum system for a high power free-electron laser SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc AB A high-average power (kW) infrared (IR) free-electron laser (FEL) is currently being commissioned for the Jefferson Laboratory FEL User Facility. The IR FEL is driven by a unique superconducting rf linac which is recirculated to recover electron beam power that is not radiated in the FEL. The design and installation of the vacuum system for the FEL involved particular attention to minimizing particulate contamination which could cause problems with the superconducting acceleration cavities and the high power FEL optics. Particulate contamination levels of all vacuum components were monitored during the cleaning process using laser scattering. Cleaning, transport, and installation procedures were developed to minimize the contamination of the complete system. We will summarize a data base we compiled of particulate contamination levels of the various components installed in the FEL vacuum system. (C) 1999 American Vacuum Society. [S0734-2101(99)15304-1]. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Dylla, HF (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2113 EP 2118 DI 10.1116/1.581735 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800061 ER PT J AU Brangan, JR Thornberg, SM Keenan, MR AF Brangan, JR Thornberg, SM Keenan, MR TI Method for measuring deuterium in erbium deuteride films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc AB Determining the quantity of deuterium in an erbium deuteride film is essential for assessing the quality of the hydriding process but is a challenging measurement to make. First, the ideal gas law cannot be applied directly due to high temperature (950 degrees C) and low temperature (25 degrees C) regions in the same manifold. Additionally, the metal hydride does not release all of the deuterium rapidly upon heating and metal evaporation occurs during extended heating periods. Therefore, the method developed must provide a means to compensate for temperature inhomogeneities and the amount of deuterium retained in the metal film while heating Mr a minimal duration. This article presents two thermal desorption methods used to evaluate the kinetics and equilibria of the deuterium desorption process at high temperatures (950 degrees C). Of primary concern is the evaluation of the quantity of deuterium remaining in these films at the high temperature. A multiple volume expansion technique provided insight into the kinetics of the deuterium evolution and metal evaporation from the film. Finally, a repeated pump-down approach yielded data that indicated approximately 10% of the deuterium is retained in the metal film at 950 degrees C and approximately 1 Torr pressure. When the total moles of deuterium determined by this method were divided by the moles of erbium determined by inductively coupled argon plasma atomic emission spectroscopy, nearly stochiometric values of 2:1 were obtained for several erbium dideuteride films. Although this work presents data for erbium and deuterium, these methods are applicable to other metal hydrides as well. (C) 1999 American Vacuum Society. [S0734-2101 (99)03604-0]. C1 Sandia Natl Labs, Dept Analyt Chem, Albuquerque, NM 87185 USA. RP Brangan, JR (reprint author), Sandia Natl Labs, Dept Analyt Chem, POB 5800, Albuquerque, NM 87185 USA. NR 13 TC 1 Z9 1 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2125 EP 2131 DI 10.1116/1.581737 PN 2 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800063 ER PT J AU Kinder, L Zhang, XF Grigorov, IL Kwon, C Jia, QX Luo, L Zhao, J AF Kinder, L Zhang, XF Grigorov, IL Kwon, C Jia, QX Luo, L Zhao, J TI Growth and characterization of Ba0.6Sr0.4TiO3 thin films on Si with Pt electrodes SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc AB Both metalorganic chemical vapor deposition and pulsed laser deposition have been used to grow Ba0.6Sr0.4TiO3 (BST) thin films on Si with Pt electrodes. The smoother Pt electrodes allow the BST to:grow with greater crystallinity. Thin Nm Pt/BST/Pt capacitors with a dielectric thickness Of around 170 nm show dielectric constants over 400 and dielectric losses in the range of 0.01-0.03 at 10 kHz. The electric/dielectric properties of the BST films are further improved by first depositing a 27 nm BST seed layer by metalorganic chemical vapor deposition followed by a 145 nm BST layer deposited by pulsed laser deposition. (C) 1999 American Vacuum Society. [S0734-2101(99)03404-1]. C1 Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, Los Alamos, NM 87545 USA. Appl Mat Inc, PDD Prod Business Grp, High K Strateg Prod Unit, Santa Clara, CA 95054 USA. RP Jia, QX (reprint author), Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, POB 1663, Los Alamos, NM 87545 USA. RI Jia, Q. X./C-5194-2008 NR 7 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2148 EP 2150 DI 10.1116/1.582098 PN 2 PG 3 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800067 ER PT J AU Lee, JW Mackenzie, KD Johnson, D Hahn, YB Hays, DC Abernathy, CR Ren, F Pearton, SJ AF Lee, JW Mackenzie, KD Johnson, D Hahn, YB Hays, DC Abernathy, CR Ren, F Pearton, SJ TI Damage to III-V devices during electron cyclotron resonance chemical vapor deposition SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID HETEROJUNCTION BIPOLAR-TRANSISTORS; TEMPERATURE ECR-CVD; MOLECULAR-BEAM EPITAXY; HBTS; DEGRADATION; GAAS/ALGAAS; INGAP/GAAS; GROWTH; BASE AB GaAs-based metal semiconductor field effect transistors (MESFETs), heterojunction bipolar transistors (HBTs), and high electron mobility transistors (HEMTs) have been exposed to ECR SiH4/NH3 discharges for deposition of SiNx passivating layers. The effect of source power, rf chuck power, pressure, and plasma composition have been investigated. Effects due to both ion damage and hydrogenation of dopants are observed. For both HEMTs and MESFETs there are no conditions where substantial increases in channel sheet resistivity are not observed, due primarily to (Si-H)degrees complex formation. In HBTs the carbon-doped base layer is the most susceptible layer to hydrogenation. Ion damage in all three devices is minimized at low rf chuck power, moderate ECR source power, and high deposition rates. (C) 1999 American Vacuum Society. [S0734-2101(99)19504-6]. C1 PlasmaTherm Inc, St Petersburg, FL 33716 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Chonbuk Natl Univ, Sch Chem Engn & Technol, Chonju 561756, South Korea. RP Lee, JW (reprint author), PlasmaTherm Inc, St Petersburg, FL 33716 USA. NR 23 TC 3 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2183 EP 2187 DI 10.1116/1.582109 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800074 ER PT J AU Cho, H Hahn, YB Hays, DC Abernathy, CR Donovan, SM MacKenzie, JD Pearton, SJ Han, J Shul, RJ AF Cho, H Hahn, YB Hays, DC Abernathy, CR Donovan, SM MacKenzie, JD Pearton, SJ Han, J Shul, RJ TI Ill-nitride dry etching: Comparison of inductively coupled plasma chemistries SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID FIELD-EFFECT TRANSISTORS; LIGHT-EMITTING DIODES; GALLIUM NITRIDE; GAN; SEMICONDUCTORS; PERFORMANCE AB A systematic study of the etch characteristics of GaN, AlN, and InN has been performed with boron halide- (BI3 and. BBr3) and interhalogen- (ICl and IBr) based inductively coupled plasmas. Maximum etch selectivities of similar to 100:1 were achieved for InN over both GaN and AlN in the BI3 mixtures due to the relatively high volatility of the InIx etch products and-the lower bond strength of InN. Maximum selectivities of similar to 14 for InN over GaN and <25 for InN over AlN were Obtained with ICl and IBr chemistries. The etched surface morphologies of GaN in these four mixtures are similar or better that-those of the control sample. (C) 1999 American Vacuum Society. [S0734-2101(99)18504-X]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Cho, H (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 21 TC 11 Z9 11 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2202 EP 2208 DI 10.1116/1.582037 PN 2 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800077 ER PT J AU Yu, ET Zuo, SL Bi, WG Tu, CW Allerman, AA Biefeld, RM AF Yu, ET Zuo, SL Bi, WG Tu, CW Allerman, AA Biefeld, RM TI Nanometer-scale compositional variations in III-V semiconductor heterostructures characterized by scanning tunneling microscopy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc ID VAPOR-PHASE EPITAXY; STRAINED-LAYER SUPERLATTICES; HIGH-TEMPERATURE PERFORMANCE; SPINODAL DECOMPOSITION; SURFACE RECONSTRUCTION; ALLOY SEMICONDUCTORS; QUANTUM-WELLS; GROWTH; INTERFACE; INAS1-XSBX AB Nanometer-scale compositional structure in InAsxP1-x/InNyAsxP1-x-y //InP heterostructures grown by gas-source molecular beam epitaxy and in InAs1-xPx/InAs1-ySby/InAs heterostructures grown by metalorganic chemical vapor deposition has been characterized using cross-sectional scanning tunneling microscopy. InAsxP1-x alloy layers are found to contain As-rich and P-rich clusters with boundaries formed preferentially within ((1) over bar 11) and (1(1) over bar 1) crystal planes. Similar compositional clustering is observed within InNyAsxP1-x-y alloy layers. Imaging of InAs1-xPx/InAs1-xSby superlattices reveals nanometer-scale clustering within both the InAs1-xPx and InAs1-ySby alloy layers, with preferential alignment of compositional features in the [<(1)over bar 12>] direction. Instances are observed of compositional features correlated across a heterojunction interface, with regions whose composition corresponds to a smaller unstrained lattice constant relative to the surrounding alloy material appearing to propagate across the interface. (C) 1999 American Vacuum Society. [S0734-2101(99)15204-7]. C1 Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Yu, ET (reprint author), Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RI Yu, Edward/A-3515-2017 OI Yu, Edward/0000-0001-9900-7322 NR 43 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2246 EP 2250 DI 10.1116/1.581755 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800085 ER PT J AU Martin, PM Matson, DW Bennett, WD Lin, Y Hammerstrom, DJ AF Martin, PM Matson, DW Bennett, WD Lin, Y Hammerstrom, DJ TI Laminated plastic microfluidic components for biological and chemical systems SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th National Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTMORE, MARYLAND SP Amer Vacuum soc AB Laminated plastic microfluidic components are being developed for; biological testing systems. and chemical sensors. Applications include a DNA thermal cycler, DNA analytical systems, electrophoretic flow systems, dialysis systems, and metal sensors for ground water.. This article describes fabrication processes developed for these plastic microfluidic components, and the fabrication of a chromium metal sensor and a microdialysis device. Most of the components have a stacked architecture; Using this architecture, the fluid flows, or is pumped through; as many as nine laminated functional levels: Functions include pumping, mixing, reaction, detection, reservoirs, separations, and electronics. Polyimide, poly(methylmethacrylate) (PMMA), and polycarbonate materials with thickness between 25 and 125 mu m are used to construct the components.This makes the components low cost, inert to many biological fluids and chemicals; and disposable. The components are fabricated by excimer laser micromachining the microchannel patterns and microstructures in the various laminates. In some,cases, micropumps are integrated into these components to move the fluids. Vias and interconnects are also cut by the laser and integrated. with micropumps. The laminates are sealed and bonded by adhesive and thermal processes and are leak tight. The parts withstand pressures as high as 790 kPa. Typical channel widths are 50 to 100 mu m; :with aspect ratios near 5. (C) 1999 American Vacuum Society. [S0734-2101(99)06604-X]. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Martin, PM (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Lin, Yuehe/D-9762-2011 OI Lin, Yuehe/0000-0003-3791-7587 NR 8 TC 34 Z9 34 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 2264 EP 2269 DI 10.1116/1.581758 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DY UT WOS:000081485800088 ER PT J AU Torri, P Hirvonen, JP Kung, H Lu, YC Nastasi, M Gibson, PN AF Torri, P Hirvonen, JP Kung, H Lu, YC Nastasi, M Gibson, PN TI Mechanical properties, stress evolution and high-temperature thermal stability of nanolayered Mo-Si-N/SiC thin films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID COMPOSITES; OXIDATION; MOSI2 AB A study of the microstructure, thermal stability, nanoindentation mechanical properties, and residual stress evolution of nanolayered Mo-Si-N/SiC thin films as a function of vacuum annealing time and temperature is reported. Multilayers of Mo-Si-N (MoSi2.2N2.5) and SiC were deposited by magnetron sputtering from planar MoSi2 and SiC targets onto single crystal silicon wafers. The relative amount of both components was varied (12.5-50 vol. % of SiC) while keeping the bilayer thickness constant (12 nm), or the bilayer thickness was varied (6-24 nm) with constant Mo-Si-N to SIC ratio (25 vol. LTC Of SiC). Mechanical properties were measured by nanoindentation on as-deposited films and films annealed in vacuum at 500 and 900 degrees C. Microstructure and thermal stability were examined by cross-sectional transmission electron microscopy, glancing angle x-ray diffraction and nuclear resonance broadening. Stress evolution induced by thermal annealing was determined by measuring optically the change in curvature of coated silicon beams. In the as-deposited state, all films exhibited an amorphous microstructure. At 900 degrees C SiC still remained amorphous, but Mo-Si-N had developed a microstructure where nanocrystals of Mo-5-Si-3 were embedded in an amorphous matrix. The interface between Mo-Si-N and SiC was indirectly shown to be stable at least up to 41 h annealing at 1075 degrees C in vacuum. The potential of Mo-Si-N as a barrier layer against intermixing between nanolayered MoSi2 and SiC at 900 degrees C has been demonstrated. Hardness, modulus and residual stress followed the volume fraction rule of mixture of both constituents of the nanolayered Mo-Si-N/SiC structure. Consequently, by optimizing the volume fraction of the constituents, zero residual stress on a silicon substrate is possible after annealing. (C) 1999 American Vacuum Society. [S0734-211X(99)09404-4]. C1 Univ Helsinki, Accelerator Lab, Dept Phys, FIN-00014 Helsinki, Finland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Commiss European Communities, Joint Res Ctr, Inst Hlth & Consumer Protect, I-21020 Ispra, Italy. Commiss European Communities, Joint Res Ctr, Inst Adv Mat, NL-1755 ZG Petten, Netherlands. RP Torri, P (reprint author), Univ Helsinki, Accelerator Lab, Dept Phys, POB 9, FIN-00014 Helsinki, Finland. NR 16 TC 7 Z9 7 U1 0 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1999 VL 17 IS 4 BP 1329 EP 1335 DI 10.1116/1.590755 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 227LW UT WOS:000082082700005 ER PT J AU Cao, XA Zhang, AP Dang, GT Cho, H Ren, F Pearton, SJ Shul, RJ Zhang, L Hickman, R Van Hove, JM AF Cao, XA Zhang, AP Dang, GT Cho, H Ren, F Pearton, SJ Shul, RJ Zhang, L Hickman, R Van Hove, JM TI Inductively coupled plasma damage in GaN Schottky diodes SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID ETCHING-INDUCED DAMAGE; HIGH-TEMPERATURE; ALN; TRANSISTORS; INGAN; ALGAN; INN AB The effects of H-2 or N-2 plasma exposure on the current-voltage characteristics of GaN Schottky diodes were examined as a function of source power and rf chuck power. Under all conditions there was a strong reduction in diode reverse breakdown voltage and an increase in forward and reverse currents, The results are consistent with creation of a thin (less than or equal to 600 Angstrom) n-type conducting surface region after ion bombardment of the GaN surface. Much of the degradation in diode quality can be recovered by annealing in N-2 at 750 degrees C. (C) 1999 American Vacuum Society. [S0734-211X(99)06804-3]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SVT Associates, Eden Prairie, MN 55344 USA. RP Cao, XA (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 24 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1999 VL 17 IS 4 BP 1540 EP 1544 DI 10.1116/1.590785 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 227LW UT WOS:000082082700037 ER PT J AU Zuo, SL Yu, ET Allerman, AA Biefeld, RM AF Zuo, SL Yu, ET Allerman, AA Biefeld, RM TI Cross-sectional scanning tunneling microscopy of InAsSb/InAsP superlattices SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 26th Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI 26) CY JAN 17-21, 1999 CL SAN DIEGO, CALIFORNIA ID STRAINED-LAYER SUPERLATTICES; MOLECULAR-BEAM EPITAXY; SEMICONDUCTOR ALLOYS; MU-M; INAS1-XSBX; EMITTERS; GAINP; INAS AB Cross-sectional scanning tunneling microscopy (STM) has been used to characterize compositional structures in InAs0.87Sb0.13/InAs0.73P0.27 and InAs0.83Sb0.17/InAs0.60P0.40 strained-layer superlattice structures grown by metal-organic chemical vapor deposition. High-resolution STM images of the (110) cross section reveal compositional features within both the InAsxSb1-x and InAsyP1-y alloy layers oriented along the [(1) over bar 12] and [<1(1)over bar>2] directions-the same as those in which features would be observed for CuPt-B type ordered alloys, Typically one variant dominates in a given area, although occasionally the coexistence of both variants is observed. Furthermore, such features in the alloy layers appear to be correlated across heterojunction interfaces in a manner that provides support for m-V alloy ordering models which suggest that compositional order can arise from strain-induced order near the surface of an epitaxially growing crystal. Finally, atomically resolved (110) images obtained from the InAs0.87Sb0.13/InAs0.73P0.27 Sample reveal compositional features in the [112] and [<(11)over bar>2] directions, i.e,, those in which features would be observed for CuPt-A type ordering. (C) 1999 American Vacuum Society. [S0734-211X(99)08404-8]. C1 Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Zuo, SL (reprint author), Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RI Yu, Edward/A-3515-2017 OI Yu, Edward/0000-0001-9900-7322 NR 23 TC 7 Z9 7 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1999 VL 17 IS 4 BP 1781 EP 1785 DI 10.1116/1.590826 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 227LW UT WOS:000082082700082 ER PT J AU Williams, PL Uselton, SP AF Williams, PL Uselton, SP TI Metrics and generation specifications for comparing volume-rendered images SO JOURNAL OF VISUALIZATION AND COMPUTER ANIMATION LA English DT Article DE volume rendering; image comparison metrics ID GRAPHICAL PERCEPTION; COMPUTER-GRAPHICS; QUALITY; MODEL; COMPRESSION; NOISE AB The goal of this paper is to lay a foundation for objectively comparing volume-rendered images, lending to objective evaluation of their accuracy and quality. The key elements of the foundation are: (I) a rigorous specification of all the input and parameters that need to be specified to define the conditions under which a volume-rendered image is generated; and (2) the basis for a methodology for difference classification, including a suite of functions or metrics to quantify and classify the difference between two volume-rendered images that will support an analysis of the relative importance of partictular differences. The results of this method can be used to study the changes caused by modifying particular parameter values, to compare and quantify changes between images of similar data sets rendered in the same way, and to detect errors in the design, implementation or modification of a volume-rendering system. If a benchmark image is available, for example one created by a high-accuracy volume-rendering system, the method can be used to evaluate the accuracy of a given image. The key contribution of this paper is the separation of the difference into noise, bias and structured difference components. Copyright (C) 1999 John Wiley (C) Sons, Ltd. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Williams, PL (reprint author), Lawrence Livermore Natl Lab, L-560, Livermore, CA 94550 USA. EM plw@llnl.gov NR 63 TC 8 Z9 8 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1049-8907 J9 J VISUAL COMP ANIMAT JI J. Vis. Comput. Animat. PD JUL-SEP PY 1999 VL 10 IS 3 BP 159 EP 178 DI 10.1002/(SICI)1099-1778(199907/09)10:3<159::AID-VIS205>3.0.CO;2-A PG 20 WC Computer Science, Software Engineering SC Computer Science GA 261WQ UT WOS:000084033800005 ER PT J AU Aschieri, P AF Aschieri, P TI Real forms of quantum orthogonal groups, q-Lorentz groups in any dimension SO LETTERS IN MATHEMATICAL PHYSICS LA English DT Article DE real forms; automorphisms; q-Lorentz group; q-Minkowski space ID ALGEBRA AB We review known real forms of the quantum orthogonal groups SOq(N). New *-conjugations are then introduced and we contruct all real forms of quantum orthogonal groups. We thus give an RTT formulation of the *-conjugations on SOq(N) that is complementary to the U-q(g) *-structure classification of Twietmeyer. In particular, we easily find and describe the real forms SOq(N-1,1) for any value of N. Quantum subspaces of the q-Minkowski space are analyzed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Aschieri, P (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Theoret Phys Grp, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Aschieri, Paolo/J-2965-2012 NR 11 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0377-9017 J9 LETT MATH PHYS JI Lett. Math. Phys. PD JUL PY 1999 VL 49 IS 1 BP 1 EP 15 DI 10.1023/A:1007636508798 PG 15 WC Physics, Mathematical SC Physics GA 244LU UT WOS:000083053700001 ER PT J AU Wishard, LA Musser, LR AF Wishard, LA Musser, LR TI Preservation strategies for geoscience literature: New technologies for an old literature SO LIBRARY RESOURCES & TECHNICAL SERVICES LA English DT Article AB In this article we describe the complex nature and history of the literature of the geosciences. We evaluate preservation technologies applicable to the formats found in the literature, such as oversize, color and folded maps and plates. Technologies profiled include deacidification, encapsulation, storage options, and facsimile creation including xerographic, photographic, plm, and digital reproduction. We present applications of the technologies and discuss suggestions for developing preservation priorities for the literature. C1 Sandia Natl Labs, Tech Lib, Albuquerque, NM 87185 USA. Penn State Univ, Earth & Mineral Sci Lib, University Pk, PA 16802 USA. RP Wishard, LA (reprint author), Sandia Natl Labs, Tech Lib, POB 5800, Albuquerque, NM 87185 USA. NR 38 TC 2 Z9 2 U1 0 U2 0 PU AMER LIBRARY ASSOC PI CHICAGO PA 50 E HURON ST, CHICAGO, IL 60611 USA SN 0024-2527 J9 LIBR RESOUR TECH SER JI Libr. Res. Tech. Serv. PD JUL PY 1999 VL 43 IS 3 BP 131 EP 139 PG 9 WC Information Science & Library Science SC Information Science & Library Science GA 227KC UT WOS:000082078700001 ER PT J AU Shannon, M Stubbs, L AF Shannon, M Stubbs, L TI Molecular characterization of Zfp54, a zinc-finger-containing gene that is deleted in the embryonic lethal mutation t(w18) SO MAMMALIAN GENOME LA English DT Article ID HUMAN-CHROMOSOME 19Q; TRANSCRIPTIONAL REPRESSION; PROTEIN GENES; MOUSE; KRUPPEL; FAMILY; DOMAIN; SUBFAMILY; ELEMENTS; CLUSTER AB Mapping studies have indicated that hundreds of Kruppel-type zinc-finger (ZNF)-containing genes are present within the genomes of mammals. One-third or more of these genes contain a second, highly conserved element termed the Kruppel-associated box (KRAB). In a recent study, several partial cDNA clones encoding distinct KRAB elements were mapped in mouse. One of these sequences, clone KRAB 10, was assigned to mouse Chromosome (Chr) 9. We have isolated the complete coding portion of the KRAB 10-containing gene and demonstrate that it is identical to Zfp54, one of several related ZNF genes that are located on mouse Chr 17 in the interval that is deleted in the t(wt18) mutation. Sequence analysis has shown that the KRAB A domain encoded by Zfp54 is highly similar to the comparable motif encoded by its nearest known neighbor, Zfp51. However, other portions of the related proteins, including their ZNF domains, are noticeably different in structure. Studies of Zfp54 expression revealed the presence of transcript in several adult tissues and in embryos throughout development, however, elevated levels of transcript were detected only in adult testis and in 7-day-old embryos. These data suggest that Zfp54 gene expression is under spatial and temporal control and may, therefore, play important roles in male germ cell and embryonic development. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Shannon, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94550 USA. OI Stubbs, Lisa/0000-0002-9556-1972 NR 25 TC 6 Z9 6 U1 0 U2 0 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 JUL PY 1999 VL 10 IS 7 BP 739 EP 743 DI 10.1007/s003359901082 PG 5 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 211FL UT WOS:000081149800016 PM 10384051 ER PT J AU Shen, E Brooks, CR Kenik, EA AF Shen, E Brooks, CR Kenik, EA TI Effect of 2, 5, 7, and 9at.% Al on the solution heat-treated (1280 degrees C, 50 hours, water quenched) structure of Ni-20at.% Mo alloy SO MATERIALS CHARACTERIZATION LA English DT Article ID SHORT-RANGE ORDER; ELECTRON-MICROSCOPY; NI4MO; PHASE; TRANSFORMATION; SYSTEM C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. NR 23 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1044-5803 EI 1873-4189 J9 MATER CHARACT JI Mater. Charact. PD JUL PY 1999 VL 43 IS 1 BP 57 EP 67 DI 10.1016/S1044-5803(99)00005-4 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 240ZZ UT WOS:000082857800007 ER PT J AU Gomm, TJ Mauseth, JA AF Gomm, TJ Mauseth, JA TI State of the technology: Ultrasonic tomography SO MATERIALS EVALUATION LA English DT Article DE compound B-scans; reflective tomography; refraction correction algorithms; ultrasonic tomography AB A discussion on the state of the technology in ultrasonic tomography is presented. First and second generation designs are compared, along with the algorithms used to reconstruct the images. Four tomographic modes are explained. The limitations of ultrasonic tomography are discussed, particularly in context of detecting spent nuclear fuel rods inside a cylindrical canister. Compound B-scans are presented as an alternative to ultrasonic tomography. To apply this technology to the inspection needs of the NDT community, refraction correction algorithms may need to be developed. The results of a compound B-scan approach are expected to be very similar to a reflective tomography approach. This allows a choice of the two methods based on their individual limitations and the inspection constraints. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Gomm, TJ (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, 2525 Fremont Ave,MS 2114, Idaho Falls, ID 83415 USA. NR 4 TC 2 Z9 2 U1 1 U2 2 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD JUL PY 1999 VL 57 IS 7 BP 747 EP 752 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 221WJ UT WOS:000081749900007 ER PT J AU Mason, T Pineda, AR Wofsy, C Goldstein, B AF Mason, T Pineda, AR Wofsy, C Goldstein, B TI Effective rate models for the analysis of transport-dependent biosensor data SO MATHEMATICAL BIOSCIENCES LA English DT Article DE biosensors; BIACORE; mass transport; binding kinetics; diffusion-reaction ID MASS-TRANSPORT; OPTICAL BIOSENSOR; KINETIC-ANALYSIS; RATE CONSTANTS; CELL-SURFACE; BINDING; DIFFUSION AB Optical biosensors, including the BIACORE, provide an increasingly popular method for determining reaction rates of biomolecules. In a flow chamber, with one reactant immobilized on a chip on the sensor surface, a solution containing the other reactant (the analyte) flows through the chamber. The time course of binding of the reactants is monitored. Scientists using the BIACORE to understand biomolecular reactions need to be able to separate intrinsic reaction rates from the effects of transport in the biosensor, For a model to provide a useful basis for such an analysis, it must reflect transport accurately, while remaining simple enough to couple with a routine for estimating reaction rates from BIACORE data, Models have been proposed previously for this purpose, consisting of an ordinary differential equation with 'effective rate coefficients' incorporating reaction and transport parameters. In this paper we investigate both the theoretical basis and numerical accuracy of these and related models. (C) 1999 Published by Elsevier Science Inc. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Theoret Div T 10, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. Univ Arizona, Program Appl Math, Tucson, AZ 85721 USA. RP Goldstein, B (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Div T 10, Theoret Biol & Biophys Grp, MS K710, Los Alamos, NM 87545 USA. FU NIGMS NIH HHS [GM35556] NR 23 TC 47 Z9 47 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0025-5564 J9 MATH BIOSCI JI Math. Biosci. PD JUL PY 1999 VL 159 IS 2 BP 123 EP 144 DI 10.1016/S0025-5564(99)00023-1 PG 22 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 215LX UT WOS:000081384100003 PM 10414030 ER PT J AU Dvorkin, J Berryman, J Nur, A AF Dvorkin, J Berryman, J Nur, A TI Elastic moduli of cemented sphere packs SO MECHANICS OF MATERIALS LA English DT Article ID COMPOSITES; INCLUSIONS; POROSITY; MEDIA AB We present a method for estimating the effective elastic moduli of a dense random pack of identical elastic spheres with elastic binder (cement). The cement concentration in the pore space varies from a few percent (where it fills the space at grain contacts) to 100%. To construct the solution we start at a small cement concentration value where the effective moduli of the pack are given by the contact cement theory (CCT). The next, and most important, step is to obtain the (unknown a priori) elastic moduli at 100% cement concentration. To do so, we: (1) treat the starting cemented pack, that is a three-phase system of grains, cement, and voids, as an elastically equivalent two-phase system of voids in a homogeneous matrix; (2) apply an effective medium theory (EMT) to find the elastic moduli of this matrix; and (3) calculate the effective moduli of this matrix with the voids filled with cement. We treat these moduli as the desired moduli of the pack with 100% cement concentration. We interpolate between this point and the initial (small cement concentration) point by using the EMT to populate the no-void elastic body with voids. Using CCT as the initial construction point gives us control over the microstructure of the composite which proves to be crucial in this modeling. The results predict the compressional elastic modulus (that is the product of density and compressional-wave velocity squared) from wave-propagation experiments on epoxy-cemented glass beads, ice-cemented Ottawa sand, and in-situ acoustic data in natural sands cemented by gas hydrate within experimental accuracy. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Dvorkin, J (reprint author), Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. RI Berryman, James/A-9712-2008 NR 21 TC 23 Z9 26 U1 0 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD JUL PY 1999 VL 31 IS 7 BP 461 EP 469 DI 10.1016/S0167-6636(99)00009-5 PG 9 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA 216MC UT WOS:000081445600003 ER PT J AU von Wittenau, AES Cox, LJ Bergstrom, PM Chandler, WP Siantar, CLH Mohan, R AF von Wittenau, AES Cox, LJ Bergstrom, PM Chandler, WP Siantar, CLH Mohan, R TI Correlated histogram representation of Monte Carlo derived medical accelerator photon-output phase space SO MEDICAL PHYSICS LA English DT Article ID POWER BREMSSTRAHLUNG CONVERTER; ELECTRON CONTAMINATION; BEAMS; SIMULATION; DOSIMETRY; MODEL AB We present a method for condensing the photon energy and angular distributions obtained from Monte Carlo simulations of medical accelerators. This method represents the output as a series of correlated histograms and as such is well-suited for inclusion::as the photon-source package for Monte Carlo codes used to determine the dose distributions in photon teletherapy. The method accounts for the isocenter-plane variations of the photon energy spectral distributions with increasing distance from the beam central axis for radiation produced in the bremsstrahlung target as well as for radiation scattered by the various treatment machine components within the accelerator head. Comparison of the isocenter energy fluence computed by this algorithm with that of the underlying full-physics Monte Carlo photon phase space indicates that energy fluence errors are less than 1% of the maximum energy fluence for a range of open-field sizes. Comparison of jaw-edge penumbrae shows that the angular distributions of the photons are accurately reproduced. The Monte Carlo sampling efficiency (the fraction of generated photons which clear the collimator jaws) of the algorithm is approximately 83% for an open 10 x 10 field, rising to approximately 96% for an open 40 x 40 held. Data file sizes for a typical medical accelerator, at a given energy, are approximately 150 kB, compared to the 1 GB size of the underlying full-physics phase space file. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)02307-X]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Virginia Commonwealth Univ, Med Coll Virginia, Richmond, VA 23298 USA. RP von Wittenau, AES (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. FU NCI NIH HHS [CA74158] NR 31 TC 54 Z9 54 U1 0 U2 5 PU AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD JUL PY 1999 VL 26 IS 7 BP 1196 EP 1211 DI 10.1118/1.598613 PG 16 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 217TL UT WOS:000081515000004 PM 10435519 ER PT J AU Wheeler, FJ Nigg, DW Capala, J Watkins, PRD Vroegindeweij, C Auterinen, I Seppala, T Bleuel, D AF Wheeler, FJ Nigg, DW Capala, J Watkins, PRD Vroegindeweij, C Auterinen, I Seppala, T Bleuel, D TI Boron neutron capture therapy (BNCT): Implications of neutron beam and boron compound characteristics SO MEDICAL PHYSICS LA English DT Article DE BNCT neutron; glioma; treatment planning ID TUMORS AB The potential efficacy of boron neutron capture therapy (BNCT) for malignant glioma is a significant function of epithermal-neutron beam biophysical characteristics as well as boron compound biodistribution characteristics. Monte Carlo analyses were performed to evaluate the relative significance of these factors on theoretical tumor control using a standard model. The existing, well-characterized epithermal-neutron sources at the Brookhaven Medical Research Reactor (BMRR), the Petten High Flux Reactor (HFR), and the Finnish Research Reactor (FiR-1) were compared. Results for a realistic accelerator design by the E. O. Lawrence Berkeley National Laboratory (LBL) are also compared. Also the characteristics of the compound p-Boronophenylaline Fructose (BPA-F) and a hypothetical next-generation compound were used in a comparison of the BMRR and a hypothetical improved reactor. All components of dose induced by an external epithermal-neutron beam fall off quite rapidly with depth in tissue. Delivery of dose to greater depths is limited by the healthy-tissue tolerance and a reduction in the hydrogen-recoil and incident gamma dose allow for longer irradiation and greater dose at a depth. Dose at depth can also be increased with a beam that has higher neutron energy (without too high a recoil dose) and a more forward peaked angular distribution. Of the existing facilities, the FiR-1 beam has the better quality (lower hydrogen-recoil and incident gamma dose) and a penetrating neutron spectrum and was found to deliver a higher value of Tumor Control Probability (TCP) than other existing beams at shallow depth. The greater forwardness and penetration of the HFR the FiR-1 at greater depths. The hypothetical reactor and accelerator beams outperform at both shallow and greater depths. In all cases, the hypothetical compound provides a significant improvement in efficacy but it is shown that the full benefit of improved compound is not realized until the neutron beam is fully optimized. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)01907-0]. C1 Idaho Natl Lab, Ctr Adv Radiat Therapies, Idaho Falls, ID 83415 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Commiss European Communities, Joint Res Ctr, HFR Unit, NL-1755 ZG Petten, Netherlands. Tech Res Ctr Finland, Reactor Lab, VTT Chem Technol, FIN-02044 Espoo, Finland. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Wheeler, FJ (reprint author), Idaho Natl Lab, Ctr Adv Radiat Therapies, POB 1625, Idaho Falls, ID 83415 USA. NR 21 TC 28 Z9 29 U1 0 U2 1 PU AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD JUL PY 1999 VL 26 IS 7 BP 1237 EP 1244 DI 10.1118/1.598618 PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 217TL UT WOS:000081515000008 PM 10435523 ER PT J AU Wilson, L Keil, K Browning, LB Krot, AN Bourcier, W AF Wilson, L Keil, K Browning, LB Krot, AN Bourcier, W TI Early aqueous alteration, explosive disruption, and reprocessing of asteroids SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID TRANSIENT VOLCANIC EXPLOSIONS; MOUNT-ST-HELENS; CARBONACEOUS CHONDRITES; CI CHONDRITES; PARENT BODIES; SOLAR NEBULA; GAS-RELEASE; AL-26; PRESSURE; CONSTRAINTS AB Several classes of chondritic meteorites experienced heterogeneous aqueous alteration and subsequent brecciation before agglomeration into the final parent bodies. These processes resulted in intimate mixing of materials altered to various degrees. In the past, this mixing has been attributed solely to impact processes. However, our investigation of the physical consequences of aqueous alteration processes in bodies accreting from a mixture of silicate and ice grains shows that aqueous alteration was commonly accompanied by substantial gas production. The asteroids may have become so internally pressurized by these gases that the sudden onset of gas release led to partial or complete disaggregation of the body. In some cases, fragments may have escaped completely from the parent asteroid and could potentially have been incorporated into other accreting asteroids. In other cases, fragments originating from different parts of the initial body, having various sizes and temperatures and exhibiting varying degrees of alteration, may have re-accreted into a second-generation object and undergone further stages of alteration. Such events could have been repeated two or three times during the lifetime of Al-26, th, likely heat source for these processes. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Univ Lancaster, Inst Environm & Biol Sci, Div Environm Sci, Lancaster LA1 4YQ, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Hawaii Ctr Volcanol, Honolulu, HI USA. RP Wilson, L (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. NR 54 TC 57 Z9 57 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 IS 4 BP 541 EP 557 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 222FD UT WOS:000081772000003 ER PT J AU Davis, AM Pellin, MJ Lewis, RS Amari, S Clayton, RN AF Davis, AM Pellin, MJ Lewis, RS Amari, S Clayton, RN TI Molybdenum- and zirconium-isotopic compositions of supernova grains. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID SILICON-CARBIDE GRAINS C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Washington Univ, McDonnell Ctr Space Sci, St Louis, MO 63130 USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 7 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A30 EP A31 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400052 ER PT J AU Krot, AN Sahijpal, S McKeegan, KD Weber, D Greshake, A Ulyanov, AA Hutcheon, ID Keil, K AF Krot, AN Sahijpal, S McKeegan, KD Weber, D Greshake, A Ulyanov, AA Hutcheon, ID Keil, K TI Mineralogy, aluminum-magnesium-isotropic, and oxygen-isotopic studies of the relic calcium-aluminum inclusions in chondrules. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID ABUNDANCES; AL-26 C1 Univ Hawaii, Hawaii Inst Geophys & Planetol, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. Univ Calif Los Angeles, Los Angeles, CA USA. Inst Planetol, Munster, Germany. Museum Naturkunde, Berlin, Germany. Moscow State Univ, Moscow, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RI McKeegan, Kevin/A-4107-2008 OI McKeegan, Kevin/0000-0002-1827-729X NR 6 TC 13 Z9 13 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A68 EP A69 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400126 ER PT J AU Krot, AN Petaev, MI Brearley, AJ Kallemeyn, GW Sears, DWG Benoit, PH Hutcheon, ID Keil, K AF Krot, AN Petaev, MI Brearley, AJ Kallemeyn, GW Sears, DWG Benoit, PH Hutcheon, ID Keil, K TI In situ growth of fayalite and hedenbergite in the ungrouped carbonaceous chondrite MacAlpine Hills 88107. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID ASTEROIDAL ALTERATION; MOKOIA C1 Univ Hawaii, Hawaii Inst Geophys & Planetol, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. Fac Sci, Dept Chem, Tokyo, Japan. Univ Arkansas, Dept Biochem & Chem, Fayetteville, AR 72701 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RI McKeegan, Kevin/A-4107-2008 OI McKeegan, Kevin/0000-0002-1827-729X NR 9 TC 13 Z9 13 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A68 EP A68 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400125 ER PT J AU Reedy, RC Marti, K Lavielle, B Gilabert, E AF Reedy, RC Marti, K Lavielle, B Gilabert, E TI Solar-proton fluxes from Kryton-81 revisited. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif San Diego, Dept Chem, La Jolla, CA 92093 USA. CEN Bordeaux Gradignan, F-33175 Gradignan, France. NR 6 TC 1 Z9 1 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A96 EP A97 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400180 ER PT J AU Schnetzler, CC Fiske, PS Garvin, JB Frawley, JJ AF Schnetzler, CC Fiske, PS Garvin, JB Frawley, JJ TI Recent developments in the search for the site of the 780,000-year-old southeast Asia impact. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Univ Calif Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Herring Bay Geophys, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A102 EP A103 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400191 ER PT J AU Welten, KC Masarik, J Nishiizumi, K Caffee, MW Wieler, R AF Welten, KC Masarik, J Nishiizumi, K Caffee, MW Wieler, R TI The stone/metal ratios for beryllium-10 and aluminum-26 as empirical shielding parameters in ordinary chondrites. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID METEORITES C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. ETH Zurich, CH-8092 Zurich, Switzerland. NR 6 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A121 EP A122 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400228 ER PT J AU Welten, KC Caffee, MW McCoy, TJ AF Welten, KC Caffee, MW McCoy, TJ TI Lewis Cliff 88019, 88021, and 88174: Three heavily weathered H4 chondrites with low terrestrial ages: Implications for local weathering conditions in Antarctica. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Mass Spectrometry, Livermore, CA 94550 USA. Museum Hist Nat, Smithsonian Inst, Dept Mineral Sci, MRC 119, Washington, DC 20560 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1999 VL 34 SU S BP A121 EP A121 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 223EA UT WOS:000081826400227 ER PT J AU Faradjian, AK Friedman, LH Chrzan, DC AF Faradjian, AK Friedman, LH Chrzan, DC TI Frank-Read sources within a continuum simulation SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Article ID DISLOCATION DYNAMICS; 3D SIMULATION; SILICON AB A continuum level simulation of dislocation dynamics has been developed and used to study the evolution of Frank-Read sources. The model is based on isotropic elasticity theory and includes the self-stress of the dislocations, as well as the dislocation-dislocation interactions. The critical stress of a Frank-Read source is calculated as a function of the source length. The simulations are used to study the strain produced by a Frank-Read source as a function of time. It is noted that the total area swept out by the source as a function of time t scales as t(3). This scaling appears to hold for a linear dependence of the dislocation velocity on stress, as well as for a stress cubed dependence. It is noted that under some conditions, a subcritically stressed Frank-Read source may produce strain for a significant length of time before complete exhaustion of its motion. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Faradjian, AK (reprint author), Cornell Univ, Dept Comp Sci, Ithaca, NY 14853 USA. RI Friedman, Lawrence/G-5650-2011 OI Friedman, Lawrence/0000-0003-2416-9903 NR 28 TC 13 Z9 13 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD JUL PY 1999 VL 7 IS 4 BP 479 EP 494 DI 10.1088/0965-0393/7/4/301 PG 16 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 243KR UT WOS:000082996900001 ER PT J AU Hornyak, GL Dillon, AC Parilla, PA Schneider, JJ Czap, N Jones, KM Fasoon, FS Mason, A Heben, MJ AF Hornyak, GL Dillon, AC Parilla, PA Schneider, JJ Czap, N Jones, KM Fasoon, FS Mason, A Heben, MJ TI Template synthesis of carbon nanotubes SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden AB The template synthesis and characterization of carbon nanotubes (CNTs) formed in porous alumina membranes (PAM) by the thermal chemical vapor decomposition (CVD) of propylene (Pr) gas are described We found that the graphitic character of CNTs improved as CVD temperature was increased from 500 to 800 degrees C. Samples showed progressive increases in metallic appearance and layered tube wall structure and decreases in electrical resistance. No further enhancement of graphitization was observed among samples formed crt 800 900 and 1000 degrees C. X-ray diffraction (XRD) indicated that long-range order was absent in all CNTs tested. Localized crystalline domains of graphitic carbon, however, were detected by Raman spectroscopy and seen in light and darkfield transmission electron microscopy (TEM) images. CNTs formed in the presence of catalytic Fe and Co particles at 600 and 700 degrees C with a Pr/N-2 flow rate of 94 seem (standard cubic centimeters per minute) showed slightly lower electrical resistance than CNTs formed in control experiments. The catalytic effects of Fe and Co were observed for samples made at 800 degrees C with a 50 seem Pr/N-2 flow rate as "nanotubes within nanotubes" were formed. No major differences were found between catalyst-containing and control samples formed at temperatures greater than or equal to 800 degrees C at 94 seem. (C) 1999 Acta Metallurgica Inc. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Essen Gesamthsch, Inst Anorgan Chem, D-45117 Essen, Germany. RP Hornyak, GL (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Schneider, Jorg /C-6308-2013 OI Schneider, Jorg /0000-0002-8153-9491 NR 10 TC 37 Z9 39 U1 0 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 83 EP 88 DI 10.1016/S0965-9773(99)00071-9 PN A PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100018 ER PT J AU Keblinski, P Phillpot, SR Wolf, D Gleiter, H AF Keblinski, P Phillpot, SR Wolf, D Gleiter, H TI On the nature of grain boundaries in nanocrystalline diamond SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden ID AMORPHOUS-CARBON; TIGHT-BINDING; PLASMAS; SILICON; ENERGY; FILMS AB The atomic structures of a few representative large-unit-cell grain boundaries thought to largely determine the behavior of nanocrystalline diamond are determined via Monte-Carlo simulation. In these highly disordered grain boundaries up to 80% of the C atoms exhibit local sp(2) bonding. However, because the three-coordinated C atoms are poorly connected to each-other, graphite-like electrical conduction through the grain boundaries is unlikely without "bridging" impurities. Surprisingly, based on their fracture energies, the high-energy, large-unit-cell boundaries are more stable against brittle decohesion into free surfaces than low-energy ones and perhaps even the perfect crystal. (C) 1999 Acta Metallurgica Inc. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. RP Keblinski, P (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 15 TC 25 Z9 25 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 339 EP 344 DI 10.1016/S0965-9773(99)00130-0 PN A PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100077 ER PT J AU He, L Allard, LF Ma, E AF He, L Allard, LF Ma, E TI A method to produce two-phase nanocomposites in solid state SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden ID NANOCRYSTALLINE; MICROSTRUCTURE; MICROHARDNESS; STRENGTH AB We demonstrate that full-density, bulk, two-phase nanocomposites can be produced starting from a powder mixture of two coarse-grained individual phases in equilibrium. Instead of going through liquid or vapor phase precursors, mixing is achieved through mechanical milling, a highly nonequilibrium driven process imposing external forcing. The precursor created is a supersaturated solid solution with nanocrystalline grain sizes. Upon subsequent hot consolidation to bulk samples, phase separation occurs on the scale of the nano-grains, forming two-phase nanocomposites in situ. Transmission electron microscopy of the Cu60Fe40 sample presented in this paper confirm that, after full density processing using the sinter forging consolidation scheme, nanophase grains are maintained and a homogeneous two-phase microstructure is obtained. (C) 1999 Acta Metallurgica Inc. C1 Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP He, L (reprint author), Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. RI Ma, En/A-3232-2010 NR 10 TC 8 Z9 8 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 543 EP 546 DI 10.1016/S0965-9773(99)00179-8 PN A PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100126 ER PT J AU Stolyarov, VV Shestakova, LO Zhu, YT Valiev, RZ AF Stolyarov, VV Shestakova, LO Zhu, YT Valiev, RZ TI Formation of metastable states in nanostructured Al- and Ti -based alloys by the SPTS technique SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden AB Nanostructured Al and Ti-based alloys have been processed by severe plastic torsion straining (SPTS). It is shown that SPTS under high pressure of these quenched alloys results in refinement of their microstructures to grain sizes of 70-100nm and leads to formation of supersaturated solid solutions. Structural changes during heating of the obtained nanostructured alloys are investigated (C) 1999 Acta Metallurgica Inc. C1 Ufa State Aviat Tech Univ, Inst Phys Adv Mat, Ufa 450025, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Stolyarov, VV (reprint author), Ufa State Aviat Tech Univ, Inst Phys Adv Mat, Ufa 450025, Russia. RI Zhu, Yuntian/B-3021-2008 OI Zhu, Yuntian/0000-0002-5961-7422 NR 5 TC 10 Z9 10 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 5-8 SI SI BP 923 EP 926 DI 10.1016/S0965-9773(99)00268-8 PN B PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 224RN UT WOS:000081912200074 ER PT J AU Wilcoxon, JP Thurston, TR Martin, JE AF Wilcoxon, JP Thurston, TR Martin, JE TI Applications of metal and semiconductor nanoclusters as thermal and photo-catalysts SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden ID HETEROGENEOUS PHOTOCATALYSIS AB We discuss studies of photo and thermally driven reactions which illustrate the unique catalytic features of nanoclusters which may be of great technical utility. The application of photocatalysts of nanosize MoS2 to oxidize organic-pollutants to CO2 is discussed. Nanosize MoS2 shows improved rates of oxidation of organics such as phenol compared to alternative bulk powders such as TiO2 or ZnO. Selective hydrogenation of pyrene using both dispersed and supported nanoclusters of Ph, Pt, and Pd is also discussed. (C) 1999 Acta Metallurgica Inc. C1 Sandia Natl Labs, Org 1152, Albuquerque, NM 87185 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, Org 1152, POB 5800, Albuquerque, NM 87185 USA. NR 8 TC 39 Z9 39 U1 2 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 5-8 SI SI BP 993 EP 997 DI 10.1016/S0965-9773(99)00285-8 PN B PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 224RN UT WOS:000081912200091 ER PT J AU Lake, B Aeppli, G Mason, TE Schroder, A McMorrow, DF Lefmann, K Isshiki, M Nohara, M Takagi, H Hayden, SM AF Lake, B Aeppli, G Mason, TE Schroder, A McMorrow, DF Lefmann, K Isshiki, M Nohara, M Takagi, H Hayden, SM TI Spin gap and magnetic coherence in a clean high-temperature superconductor SO NATURE LA English DT Article ID LA2-XSRXCUO4; FLUCTUATIONS; LA1.86SR0.14CUO4; SPECTROSCOPY; ANISOTROPY; SCATTERING; DYNAMICS AB A notable aspect of high-temperature superconductivity in the copper oxides is the unconventional nature of the underlying paired-electron state. A direct manifestation of the unconventional state is a pairing energy-that is, the energy required to remove one electron from the superconductor-that varies (between zero and a maximum value) as a function of momentum, or wavevector(1,2): the pairing energy for conventional superconductors is wavevector-independent(3,4). The wavefunction describing the superconducting state will include the pairing not only of charges, but also of the spins of the paired charges. Each pair is usually in the form of a spin singlet(5), so there will also be a pairing energy associated with transforming the spin singlet into the higher-energy spin triplet form without necessarily unbinding the charges. Here we use inelastic neutron scattering to determine the wavevector-dependence of spin pairing in La2-xSrxCuO4, the simplest high-temperature superconductor. We find that the spin pairing energy (or 'spin gap') is wavevector independent, even though superconductivity significantly alters the wavevector dependence of the spin fluctuations at higher energies. C1 Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Riso Natl Lab, Dept Condensed Matter Phys & Chem, DK-4000 Roskilde, Denmark. NEC Res Inst, Princeton, NJ 08540 USA. Univ Karlsruhe, Dept Phys, D-76128 Karlsruhe, Germany. Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 1068666, Japan. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. RP Lake, B (reprint author), Univ Toronto, Dept Phys, 60 St George St, Toronto, ON M5S 1A7, Canada. RI McMorrow, Desmond/C-2655-2008; Takagi, Hidenori/B-2935-2010; Hayden, Stephen/F-4162-2011; NOHARA, Minoru/B-1476-2011; Mason, Thomas/M-5809-2014; Lefmann, Kim/M-9228-2014; OI McMorrow, Desmond/0000-0002-4947-7788; Hayden, Stephen/0000-0002-3209-027X; Mason, Thomas/0000-0003-1880-3971; Lefmann, Kim/0000-0003-4282-756X; Lake, Bella/0000-0003-0034-0964 NR 30 TC 94 Z9 94 U1 2 U2 14 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 1 PY 1999 VL 400 IS 6739 BP 43 EP 46 DI 10.1038/21840 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 213DA UT WOS:000081255700043 ER PT J AU van Schilfgaarde, M Abrikosov, IA Johansson, B AF van Schilfgaarde, M Abrikosov, IA Johansson, B TI Origin of the Invar effect in iron-nickel alloys SO NATURE LA English DT Article ID SPIN DYNAMICS; TRANSITION; INSTABILITY; ANOMALIES; DISORDER; MAGNETS; METALS; STATES; FILMS; FE AB In 1897 Guillaume(1) discovered that face-centred cubic alloys of iron and nickel with a nickel concentration of around 35 atomic per cent exhibit anomalously low (almost zero) thermal expansion over a wide temperature range. This effect, known as the Invar effect, has since been found in various ordered and random alloys and even in amorphous materials'. Other physical properties of Invar systems, such as atomic volume, elastic modulus, heat capacity, magnetization and Curie (or Neel) temperature, also show anomalous behaviour. Invar alloys are used in instrumentation, for example as hair springs in watches. It has long been realized that the effect is related to magnetism(2,3); but a full understanding is still lacking. Here we present nb initio calculations of the volume dependences of magnetic and thermodynamic properties for the most typical Invar system, a random face-centred cubic iron-nickel alloy, in which we allow for noncollinear spin alignments-that is, spins that may be canted with respect to the average magnetization direction. We find that the magnetic structure is characterized, even at zero temperature, by a continuous transition from the ferromagnetic state at high volumes to a disordered non-collinear configuration at low volumes. There is an additional, comparable contribution to the net magnetization from the changes in the amplitudes of the local magnetic moments. The non-collinearity gives rise to an anomalous volume dependence of the binding energy, and explains other peculiarities of Invar systems. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. RP van Schilfgaarde, M (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 28 TC 218 Z9 219 U1 13 U2 98 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 1 PY 1999 VL 400 IS 6739 BP 46 EP 49 DI 10.1038/21848 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 213DA UT WOS:000081255700044 ER PT J AU Waldo, GS Standish, BM Berendzen, J Terwilliger, TC AF Waldo, GS Standish, BM Berendzen, J Terwilliger, TC TI Rapid protein-folding assay using green fluorescent protein SO NATURE BIOTECHNOLOGY LA English DT Article DE protein folding; solubility; reporter; aggregation directed evolution; green fluorescent protein; inclusion body ID MOLECULAR EVOLUTION; DIRECTED EVOLUTION; ESCHERICHIA-COLI; IN-VITRO; EXPRESSION; IDENTIFICATION; CHROMOPHORE; MUTATIONS; FERRITIN; MUTANTS AB Formation of the chromophore of green fluorescent protein (GFP) depends on the correct folding of the protein. We constructed a "folding reporter" vector, in which a test protein is expressed as an N-terminal fusion with GFP. Using a test panel of 20 proteins, we demonstrated that the fluorescence of Escherichia coli cells expressing such GFP fusions is related to the productive folding of the upstream protein domains expressed alone. We used this fluorescent indicator of protein folding to evolve proteins that are normally prone to aggregation during expression in E. coli into closely related proteins that ford robustly and are fully soluble and functional. This approach to improving protein folding does not require functional assays for the protein of interest and provides a simple route to improving protein folding and expression by directed evolution. 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. Univ New Mexico, Albuquerque, NM 87131 USA. RP Waldo, GS (reprint author), Univ Calif Los Alamos Natl Lab, Struct Biol Grp, MS-M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 31 TC 521 Z9 537 U1 4 U2 79 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 JUL PY 1999 VL 17 IS 7 BP 691 EP 695 DI 10.1038/10904 PG 5 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 213WU UT WOS:000081296900030 PM 10404163 ER PT J AU Hwang, KY Chung, JH Kim, SH Han, YS Cho, YJ AF Hwang, KY Chung, JH Kim, SH Han, YS Cho, YJ TI Structure-based identification of a novel NTPase from Methanococcus jannaschii SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID COMPLETE GENOME SEQUENCE; TRANSFER-RNA SYNTHETASE; CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; SACCHAROMYCES-CEREVISIAE; THERMUS-THERMOPHILUS; PROTEIN; DATABASE; 6-N-HYDROXYLAMINOPURINE; RESOLUTION AB Almost half of the entire set of predicted genomic products from Methanococcus jannaschii are classified as functionally unknown hypothetical proteins. We present a structure-based identification of the biochemical function of a protein with an as yet unknown function from a M. jannaschii gene, Mj0226. The crystal structure of Mj0226 protein determined at 2.2 Angstrom, resolution reveals that the protein is a homodimer and each monomer folds into an elongated alpha/beta structure of a new ford family. Comparisons of Mj0226 protein with protein structures in the database, however, indicate that one part of the protein is homologous to some of the nucleotide-binding proteins. Biochemical analysis shows that Mj0226 protein is a novel nucleotide triphosphatase that can efficiently hydrolyze nonstandard nucleotides such as XTP to XMP or ITP to IMP, but not the standard nucleotides, in the presence of Mg2+ or Mn2+ ions. C1 Korea Inst Sci & Technol, Struct Biol Ctr, Seoul 130650, South Korea. Korea Univ, Grad Sch Biotechnol, Seoul 136701, South Korea. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Cho, YJ (reprint author), Korea Inst Sci & Technol, Struct Biol Ctr, POB 131, Seoul 130650, South Korea. NR 41 TC 101 Z9 105 U1 0 U2 3 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD JUL PY 1999 VL 6 IS 7 BP 691 EP 696 PG 6 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 212LE UT WOS:000081217500025 PM 10404228 ER PT J AU Hush, DR AF Hush, DR TI Training a sigmoidal node is hard SO NEURAL COMPUTATION LA English DT Article ID NEURAL NETWORKS; APPROXIMATION; COMPLEXITY; EFFICIENT AB This article proves that the task of computing near-optimal weights for sigmoidal nodes under the L-1 regression norm is NP-Hard. For the special case where the sigmoid is piecewise linear, we prove a slightly stronger result: that computing the optimal weights is NP-Hard. These results parallel that for the one-node pattern recognition problem-that determining the optimal weights for a threshold logic node is also intractable. Our results have important consequences for constructive algorithms that build a regression model one node at a time. It suggests that although such methods are (in principle) capable of producing efficient size representations (Barron, 1993; Jones, 1992), finding such representations may be computationally intractable. These results holds only in the deterministic sense; that is, they do not exclude the possibility that such representations may be found efficiently with high probability. In fact it motivates the use of heuristic or randomized algorithms for this problem. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hush, DR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 8 Z9 8 U1 0 U2 0 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 USA SN 0899-7667 J9 NEURAL COMPUT JI Neural Comput. PD JUL 1 PY 1999 VL 11 IS 5 BP 1249 EP 1260 DI 10.1162/089976699300016449 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA 208KL UT WOS:000080990000012 ER PT J AU Cvitanovic, P Dettmann, CP Mainieri, R Vattay, G AF Cvitanovic, P Dettmann, CP Mainieri, R Vattay, G TI Trace formulae for stochastic evolution operators: smooth conjugation method SO NONLINEARITY LA English DT Article AB The trace formula for the evolution operator associated with nonlinear stochastic flows with weak additive noise is cast in the path integral formalism. We integrate over the neighbourhood of a given saddlepoint exactly by means Of a smooth conjugacy, a locally analytic nonlinear change of field variables. The perturbative corrections are transferred to the corresponding Jacobian, which we expand in terms of the conjugating function, rather than the action used in defining the path integral. The new perturbative expansion which follows by a recursive evaluation of derivatives appears more compact than the standard Feynman diagram perturbation theory. The result is a stochastic analogue of the Gutzwiller trace formula with the '(h) over bar' corrections computed an order higher than what has so far been attainable in stochastic and quantum mechanical applications. C1 Niels Bohr Inst, Ctr Chaos & Turbulence Studies, DK-2100 Copenhagen, Denmark. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Eotvos Lorand Univ, Dept Solid State Phys, H-1088 Budapest, Hungary. RP Cvitanovic, P (reprint author), Niels Bohr Inst, Ctr Chaos & Turbulence Studies, Blegdamsvej 17, DK-2100 Copenhagen, Denmark. OI Cvitanovic, Predrag/0000-0001-6169-0509 NR 27 TC 15 Z9 15 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0951-7715 J9 NONLINEARITY JI Nonlinearity PD JUL PY 1999 VL 12 IS 4 BP 939 EP 953 DI 10.1088/0951-7715/12/4/312 PG 15 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 219RY UT WOS:000081621900012 ER PT J AU Hooper, EB Pearlstein, LD Bulmer, RH AF Hooper, EB Pearlstein, LD Bulmer, RH TI MHD equilibria in a spheromak sustained by coaxial helicity injection SO NUCLEAR FUSION LA English DT Article ID MAGNETIZED PLASMA SOURCE; CURRENT DRIVE; STABILITY; RELAXATION; LIMITS AB Spheromaks sustained by coaxial helicity injection differ from unsustained spheromaks in the profiles of the ratio of current to magnetic field and of the safety factor. Ideal MHD modelling with Taylor relaxed profiles in the injector predicts that the safety factor in the confined region will generally lie between 0.5 and 1, with a divergence on the separatrix since the open field lines carry current from the injector. The safety factor can be single or double valued, depending on the current profile. The modelling predicts that there are no mode rational surfaces with m = 1 except very near the separatrix; this is expected to determine the unstable resistive tearing modes associated with the dynamo which drives the discharge current. The resulting low magnetic shear has a beta (similar to 2%) at the Mercier limit, which can be improved by current profiles differing significantly from the Taylor state or by other effects such as plasma flow. Examples are presented for the Sustained Spheromak Physics Experiment recently constructed at LLNL. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Hooper, EB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 32 TC 61 Z9 61 U1 1 U2 3 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1999 VL 39 IS 7 BP 863 EP 871 DI 10.1088/0029-5515/39/7/303 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 224JB UT WOS:000081893300003 ER PT J AU Callahan-Miller, DA Tabak, M AF Callahan-Miller, DA Tabak, M TI A distributed radiator, heavy ion target driven by Gaussian beams in a multibeam illumination geometry SO NUCLEAR FUSION LA English DT Article ID INERTIAL CONFINEMENT FUSION; DESIGN AB An inertial confinement fusion target driven by ion beams in a multibeam illumination geometry is presented. Two dimensional integrated LASNEX calculations (ion beam deposition to fusion burn in one computer simulation) predict a gain of greater than 65 for this target. Each beam has a Gaussian density profile and is focused to an elliptically shaped spot. Multiple beam ellipses are overlayed to form an annulus on the end of the cylindrical hohlraum. The beams enter at angles relative to the cylindrical axis of the hohlraum that are consistent with both liquid wall chamber protection and the space required for a final focusing system upstream. For an accelerator that is 25% efficient (eta = 0.25), a gain G of 65 leads to eta G greater than 16; a reactor with a reasonably small recirculating power fraction requires eta G greater than 8-10. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Callahan-Miller, DA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 18 TC 43 Z9 43 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1999 VL 39 IS 7 BP 883 EP 891 DI 10.1088/0029-5515/39/7/305 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 224JB UT WOS:000081893300005 ER PT J AU Allshouse, GO Olson, RE Callahan-Miller, DA Tabak, M AF Allshouse, GO Olson, RE Callahan-Miller, DA Tabak, M TI Deposition and drive symmetry for light ion ICF targets SO NUCLEAR FUSION LA English DT Article ID INERTIAL CONFINEMENT FUSION; DESIGN; LIBRA AB Light ion beam ICF is a concept in which intense beams of low atomic number ions would be used to drive ICF targets to ignition and gain. Three dimensional analytic approximations indicate that at least twelve beams would be required to drive an indirect drive target with adequate symmetry. Here, results from two dimensional numerical simulations are presented describing the ion deposition and drive symmetry aspects of such a target for which the ion beams are approximated as ring sources. For adequate symmetry in the two dimensional calculations, the simulations required six ring sources and two pole sources during the low power 'foot' pulse and four ring sources during the main ion beam drive pulse. If each ring represents five individual beams, this corresponds to 32 beams in the foot pulse and 20 beams in the main pulse. The corresponding two dimensional integrated LASNEX calculation, simulating the target from ion beam input to ignition and burn in the same code run, produced 591 MJ of thermonuclear yield with lithium ion beam sources containing a total input energy of 16 MJ. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Allshouse, GO (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 10 Z9 10 U1 0 U2 2 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1999 VL 39 IS 7 BP 893 EP 899 DI 10.1088/0029-5515/39/7/306 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 224JB UT WOS:000081893300006 ER PT J AU Strachan, JD Bell, MG Bush, CE Chang, Z Fredrickson, ED Park, HK Ramsey, AT Scott, SD Taylor, G AF Strachan, JD Bell, MG Bush, CE Chang, Z Fredrickson, ED Park, HK Ramsey, AT Scott, SD Taylor, G TI Rollover: confinement degradation during TFTR discharges SO NUCLEAR FUSION LA English DT Article ID FUSION TEST REACTOR; BEAM FUELING PROFILE; ENERGY CONFINEMENT; MHD ACTIVITY; PLASMAS; SUPERSHOTS; DEUTERIUM; TRITIUM; MODES; POWER AB The time evolution is described of TFTR neutral beam heated plasmas that often featured a decreasing energy content called 'rollover'. Rollover affects the gross plasma parameters such as energy contest and fusion power produced, as well as the central plasma parameters and the plasma transport coefficients. Rollover was studied using a database of all the TFTR plasmas produced over a two year period. The plasma behaviour at the time of peak energy content was related to the behaviour at a later quasi-equilibrium time. The main conclusion is that limiter power handling issues were the underlying cause of TFTR rollover. This study re-emphasizes the fact that power handling is an important issue for plasma facing components in tokamaks. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Strachan, JD (reprint author), Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. NR 26 TC 5 Z9 5 U1 1 U2 2 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1999 VL 39 IS 7 BP 919 EP 931 DI 10.1088/0029-5515/39/7/308 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 224JB UT WOS:000081893300008 ER PT J AU Liu, Y Pogorelsky, IV Cline, D AF Liu, Y Pogorelsky, IV Cline, D TI Gas breakdown limit and maximum acceleration gradient for inverse Cherenkov laser accelerator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE accelerator; avalanche; breakdown; Cherenkov; ionization; laser; threshold; tunneling ID WAKE-FIELD ACCELERATION; ELECTRON-PLASMA WAVES; HIGH-INTENSITY LASERS; PULSE; SCATTERING; VACUUM; RAMAN AB Laser intensity thresholds for CO2 laser-induced gas breakdown, such as tunneling, multiphoton, and cascade ionization have been estimated for the inverse Cherenkov accelerator experiment at the Brookhaven Accelerator Test Facility. The gas breakdown is dominated by cascade ionization and the maximum acceleration gradient is up to 300 MeV/m for a 3 ps CO2 laser. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Angeles, Dept Phys & Astron, Ctr Adv Accelerators, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, Accelerator Test Facil, Upton, NY 11973 USA. RP Liu, Y (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Ctr Adv Accelerators, Los Angeles, CA 90095 USA. NR 40 TC 1 Z9 1 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 JUL 1 PY 1999 VL 430 IS 2-3 BP 171 EP 179 DI 10.1016/S0168-9002(99)00222-3 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600001 ER PT J AU Kim, SY Kim, YG Ryu, SS Kang, JH Simon-Gillo, J Sullivan, JP van Heck, HW Xu, GH AF Kim, SY Kim, YG Ryu, SS Kang, JH Simon-Gillo, J Sullivan, JP van Heck, HW Xu, GH TI Tests of MVD prototype pad detector with a beta(-) source SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID MULTIPLICITY-VERTEX DETECTOR; DESIGN; PREAMPLIFIER; ELECTRONICS; COLLISIONS; SHAPER AB The MVD group has been testing two versions of silicon pad detectors. One design uses a single metal layer for readout trace routing. The second type uses two layers of metal, allowing for greatly simplified signal routing. However, because the readout traces for the pads pass over the other pads in the same column (separated by an oxide layer), the double-metal design introduces crosstalk into the system. A simple test stand using a Sr-90 beta(-) source with scintillator triggers was made to estimate the crosstalk. The crosstalk between pads in the same column of the pad detector was 1.6-3.1%. The values measured between pads in different columns were very close to zero. The measured crosstalk was below our maximum allowed value of 7.8%. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Yonsei Univ, Dept Phys, Seodaemum Ku, Seoul 120749, South Korea. Univ Calif Los Alamos Natl Lab, Grp P25, Los Alamos, NM 87545 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. RP Kang, JH (reprint author), Yonsei Univ, Dept Phys, Seodaemum Ku, 134 Shinchon Dong, Seoul 120749, South Korea. NR 18 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 198 EP 209 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600004 ER PT J AU Afanasiev, S Alber, T Appelshauser, H Bachler, J Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Bieser, F Billmeier, A Blyth, CO Bock, R Bormann, C Bracinik, J Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Cyprian, M Dunn, J Eckardt, V Eckhardt, F Empl, T Eschke, J Ferguson, MI Fessler, H Fischer, HG Flierl, D Fodor, Z Frankenfeld, U Foka, P Freund, P Friese, V Ftacnik, J Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hlinka, V Huang, I Hummler, H Igo, G Irmscher, D Ivanov, M Janik, R Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Liebicher, K Lynen, U Malakhov, AI Margetis, S Markert, C Marks, C Mayes, B Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Pestov, Y Petridis, A Pikna, M Pimpl, W Pinsky, L Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Schafer, E Schmidt, R Schmischke, D Schmitz, N Schonfelder, S Semenov, AY Seyboth, J Seyboth, P Seyerlein, J Sikler, F Sitar, B Skrzypczak, E Squier, GTA Stelzer, H Stock, R Strmen, P Strobele, H Struck, C Susa, T Szarka, I Szentpetery, I Szymanski, P Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Vranic, D Wang, FQ Weerasundara, DD Wenig, S Whitten, C Wieman, H Wienold, T Wood, L Yates, TA Zimanyi, J Zhu, XZ Zybert, R AF Afanasiev, S Alber, T Appelshauser, H Bachler, J Barna, D Barnby, LS Bartke, J Barton, RA Betev, L Bialkowska, H Bieser, F Billmeier, A Blyth, CO Bock, R Bormann, C Bracinik, J Brady, FP Brockmann, R Brun, R Buncic, P Caines, HL Cebra, D Cooper, GE Cramer, JG Csato, P Cyprian, M Dunn, J Eckardt, V Eckhardt, F Empl, T Eschke, J Ferguson, MI Fessler, H Fischer, HG Flierl, D Fodor, Z Frankenfeld, U Foka, P Freund, P Friese, V Ftacnik, J Fuchs, M Gabler, F Gal, J Ganz, R Gazdzicki, M Gladysz, E Grebieszkow, J Gunther, J Harris, JW Hegyi, S Henkel, T Hill, LA Hlinka, V Huang, I Hummler, H Igo, G Irmscher, D Ivanov, M Janik, R Jacobs, P Jones, PG Kadija, K Kolesnikov, VI Kowalski, M Lasiuk, B Levai, P Liebicher, K Lynen, U Malakhov, AI Margetis, S Markert, C Marks, C Mayes, B Melkumov, GL Mock, A Molnar, J Nelson, JM Oldenburg, M Odyniec, G Palla, G Panagiotou, AD Pestov, Y Petridis, A Pikna, M Pimpl, W Pinsky, L Piper, A Porter, RJ Poskanzer, AM Poziombka, S Prindle, DJ Puhlhofer, F Rauch, W Reid, JG Renfordt, R Retyk, W Ritter, HG Rohrich, D Roland, C Roland, G Rudolph, H Rybicki, A Sammer, T Sandoval, A Sann, H Schafer, E Schmidt, R Schmischke, D Schmitz, N Schonfelder, S Semenov, AY Seyboth, J Seyboth, P Seyerlein, J Sikler, F Sitar, B Skrzypczak, E Squier, GTA Stelzer, H Stock, R Strmen, P Strobele, H Struck, C Susa, T Szarka, I Szentpetery, I Szymanski, P Sziklai, J Toy, M Trainor, TA Trentalange, S Ullrich, T Vassiliou, M Veres, G Vesztergombi, G Vranic, D Wang, FQ Weerasundara, DD Wenig, S Whitten, C Wieman, H Wienold, T Wood, L Yates, TA Zimanyi, J Zhu, XZ Zybert, R TI The NA49 large acceptance hadron detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE hadron detector; wide acceptance; tracking; particle identification; high track density ID TIME PROJECTION CHAMBERS; HEAVY-ION COLLISIONS; SYSTEM; PERFORMANCE; TRACKING; TPCS AB The NA49 detector is a wide acceptance spectrometer for the study of hadron production in p + p, p + A, and A + A collisions at the CERN SPS. The main components are 4 large-volume TPCs for tracking and particle identification via dE/dx. TOF scintillator arrays complement particle identification Calorimeters for transverse energy determination and triggering, a detector for centrality selection in p + A collisions, and beam definition detectors complete the set-up. A description of all detector components is given with emphasis on new technical realizations. Performance and operational experience are discussed in particular with respect to the high track density environment of central Pb + Pb collisions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 CERN, Div EP, CH-1211 Geneva 23, Switzerland. Joint Nucl Res Inst, Dubna 141980, Russia. Max Planck Inst Phys, D-80805 Munich, Germany. Gesell Schwerionenforsch, GSI, Darmstadt, Germany. KFKI, Res Inst Particle & Nucl Phys, Budapest, Hungary. Univ Birmingham, Birmingham, W Midlands, England. Inst Nucl Phys, Krakow, Poland. Univ Calif Los Angeles, Los Angeles, CA USA. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Frankfurt, Fachbereich Phys, D-6000 Frankfurt, Germany. Comenius Univ, Bratislava 81806, Slovakia. Univ Calif Davis, Davis, CA 95616 USA. Univ Washington, Nucl Phys Lab, Seattle, WA 98195 USA. Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany. Univ Houston, Houston, TX USA. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Yale Univ, New Haven, CT USA. Rudjer Boskovic Inst, Zagreb, Croatia. Univ Athens, Dept Phys, Athens, Greece. RP Wenig, S (reprint author), CERN, Div EP, CH-1211 Geneva 23, Switzerland. RI Barnby, Lee/G-2135-2010; Levai, Peter/A-1544-2014 OI Barnby, Lee/0000-0001-7357-9904; NR 33 TC 256 Z9 259 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 JUL 1 PY 1999 VL 430 IS 2-3 BP 210 EP 244 DI 10.1016/S0168-9002(99)00239-9 PG 35 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600005 ER PT J AU Hu, MY Toellner, TS Sturhahn, W Hession, PM Sutter, JP Alp, EE AF Hu, MY Toellner, TS Sturhahn, W Hession, PM Sutter, JP Alp, EE TI A high-resolution monochromator for inelastic nuclear resonant scattering experiments using Sn-119 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SYNCHROTRON-RADIATION; AVALANCHE PHOTODIODES; X-RAYS AB We report a silicon crystal monochromator with an angular acceptance of 14.1 mu rad and an energy bandwidth of 3.6 meV at 23.880 keV X-ray energy - an energy resolution delta E/E of 1.5 x 10(-7). In combination with an undulator source, the monochromator is used to measure the partial phonon density of states of Sn in (SnO2)-Sn-119 by the method of inelastic nuclear resonant scattering using the 23.880 keV nuclear transition of Sn-119. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. RP Hu, MY (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Hu, Michael/C-7571-2013 OI Hu, Michael/0000-0002-3718-7169 NR 19 TC 14 Z9 14 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 271 EP 276 DI 10.1016/S0168-9002(99)00229-6 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600008 ER PT J AU Deleplanque, MA Lee, IY Vetter, K Schmid, GJ Stephens, FS Clark, RM Diamond, RM Fallon, P Macchiavelli, AO AF Deleplanque, MA Lee, IY Vetter, K Schmid, GJ Stephens, FS Clark, RM Diamond, RM Fallon, P Macchiavelli, AO TI GRETA: utilizing new concepts in gamma-ray detection SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SEGMENTED GERMANIUM DETECTORS; SUPERDEFORMED BAND; SPECTROMETER; GAMMASPHERE; EUROBALL; LINE AB We present a new concept for gamma-ray detector arrays. An example, called GRETA (Gamma-Ray Energy Tracking Array), consists of highly segmented HPGe detectors covering 4 pi solid angle. The new feature is the ability to track the scattering sequence of incident gamma-rays and in every event, this potentially allows one to measure with high resolution the energy deposited, the location (incident angle) and the time of each gamma-ray that hits the array. GRETA will be of order of 1000 times more powerful than the best present arrays, such as Gammasphere or Euroball, and will provide access to new physics. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Deleplanque, MA (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. NR 32 TC 136 Z9 136 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 292 EP 310 DI 10.1016/S0168-9002(99)00187-4 PG 19 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600010 ER PT J AU Carman, DS Bland, LC Chant, NS Eads, A Gu, T Huber, GM Huffman, J Klyachko, A Markham, BC Roos, PG Schwandt, P Solberg, K AF Carman, DS Bland, LC Chant, NS Eads, A Gu, T Huber, GM Huffman, J Klyachko, A Markham, BC Roos, PG Schwandt, P Solberg, K TI A neutron detector for (p,np) coincidence studies SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutron detection; (n,p); drift chambers AB A neutron detector with moderate energy resolution (similar to 3 MeV) has been built for neutrons in the energy range 75-175 MeV. The detector was designed for coincidence scattering experiments. The design eliminates the need for long neutron flight paths necessary for comparable energy resolution time-of-flight measurements with a comparable efficiency-solid angle product (0.02 msr). The detector consists of thin plastic scintillators in which the neutron undergoes n-p elastic scattering. The second-scattered protons are tracked by drift chambers and detected in a sodium iodide array. The design motivations and features are presented along with results from detailed in-beam experimental tests. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Indiana Univ, Cyclotron Facil, Bloomington, IN 47408 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Regina, Regina, SK S4S 0A2, Canada. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. RP Carman, DS (reprint author), Thomas Jefferson Natl Accelerator Facil, Dept Phys, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 382 EP 399 DI 10.1016/S0168-9002(99)00159-X PG 18 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600018 ER PT J AU Russell, SJ AF Russell, SJ TI Unstable matrix equations and their relationship to measuring the emittance of an electron beam using beam position monitors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE beam instrumentation; data analysis; error analysis; matrix theory; measurement theory AB In general, the spatial distributions of electron beams from photoinjectors are unknown and are not well approximated by a Gaussian. Therefore, when measuring the emittance, it is important to make no assumptions about the beam's spatial distribution. An emittance diagnostic that fulfills this requirement uses beam position monitors to measure the second moment of the electron beam's image charge. This information, coupled with the beam line's transfer matrix, forms a set of linear equations. The least squares solution to these equations estimates the necessary beam parameters. More often than not, however, this solution is unstable and amplifies the errors in the second moment measurement. For this diagnostic to be viable, a stable implementation has to be found. Described here is an approach that accomplishes this task. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Russell, SJ (reprint author), Univ Calif Los Alamos Natl Lab, MS H851, Los Alamos, NM 87545 USA. NR 8 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 498 EP 506 DI 10.1016/S0168-9002(99)00234-X PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600026 ER PT J AU Pisharody, M Semones, E Job, PK AF Pisharody, M Semones, E Job, PK TI Dose measurements of bremsstrahlung-produced neutrons from thick targets SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ELECTRON STORAGE-RINGS; GAS BREMSSTRAHLUNG; RESONANCE AB Photons of sufficiently high energies (E-gamma greater than or equal to 5-15 MeV) can produce neutrons by means of photonuclear interactions. Bremsstrahlung from high energy electron storage rings, which have an energy range of zero to the maximum energy of the particle beam, can interact with beamline components like beam stops and collimators generating photoneutrons of varying energies. This paper presents the results of simultaneous measurements of bremsstrahlung power and corresponding photoneutron dose equivalent rate at the insertion device beamlines of the Advanced Photon Source, using a lead-glass calorimeter and an Andersson-Braun remmeter. Targets made of Fe, Cu, W, and Pb are placed in the bremsstrahlung beam inside the first optics enclosure of the insertion device beamlines. The photoneutron dose equivalent rates, normalized to bremsstrahlung power, beam current, and storage ring pressure, are measured for the four targets. The photoneutron dose equivalent rates, normalized to the bremsstrahlung power and corrected for systematic variations, are given as 2.2 +/- 0.5 rem/h/W for Fe, 3.0 +/- 0.5 rem/h/W for Cu, 3.8 +/- 0.5 rem/h/W for W, and 3.7 +/- 0.8 rem/h/W for Pb targets, at a distance of 0.8 m perpendicular from the target center. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Pisharody, M (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 7 Z9 8 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1999 VL 430 IS 2-3 BP 542 EP 558 DI 10.1016/S0168-9002(99)00215-6 PG 17 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 212KV UT WOS:000081216600031 ER PT J AU Agosteo, S Fasso, A Ferrari, A Sala, PR Silari, M de Fatis, PT AF Agosteo, S Fasso, A Ferrari, A Sala, PR Silari, M de Fatis, PT TI Attenuation curves in concrete for neutrons produced by 710 MeV alpha-particles on steel and water and by 337-390 MeV/u Ne ions on Al, Cu and Pb SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article DE ion accelerator; shielding; dose equivalent; attenuation length; source term ID MEV-NUCLEON; DISTRIBUTIONS; TARGETS; FLUENCE; CARBON; YIELDS; MODEL AB The attenuation in ordinary concrete of the total dose equivalent due to neutrons produced by 710 MeV alpha-particles on steel and water and by 337-390 MeV/u Ne ions on Al, Cu and Pb was calculated with the FLUKA Monte Carlo code. Experimental data (taken from the literature) of the neutron double differential distributions were utilized for the source in the calculations. The contribution of all secondaries (neutrons, photons and protons) produced in the concrete shield was considered. Source terms and attenuation lengths are given as a function of energy and emission angle. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Politecn Milan, Dipartimento Ingn Nucl, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. CERN, CH-1211 Geneva 23, Switzerland. Fdn TERA, I-28100 Novara, Italy. RP Agosteo, S (reprint author), Politecn Milan, Dipartimento Ingn Nucl, Via Ponzio 34-3, I-20133 Milan, Italy. EM stefano.agosteo@polimi.it RI sala, paola/E-2868-2013 OI sala, paola/0000-0001-9859-5564 NR 33 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1999 VL 155 IS 1-2 BP 102 EP 109 DI 10.1016/S0168-583X(99)00460-7 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 217BT UT WOS:000081480100015 ER PT J AU Jaschke, J Ruter, HD Gerdau, E Smirnov, GV Sturhahn, W Pollmann, J AF Jaschke, J Ruter, HD Gerdau, E Smirnov, GV Sturhahn, W Pollmann, J TI A single line linearly polarized source of 14.4 keV radiation by means of resonant absorption SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article DE polarized gamma-radiation; Mossbauer effect ID SYNCHROTRON-RADIATION; NUCLEAR; SCATTERING; ALPHA-FE-57; DIFFRACTION; CRYSTALS; RAYS AB A single line linear polarized source of 14.4 keV is realized in a conventional Mossbauer setup. In combination with the dichroism of a magnetized (FeBO3)-Fe-57 or alpha-Fe-57 absorber a single line unpolarized Co-57<(Cr)under bar>- Or Co-57<(Pt)under bar>-source delivers greater than or equal to 90% linear polarized radiation and about 25% of its primary intensity. The optimal value of the internal magnetic field of each absorber is selected by temperature adjustment. Calculations and measurements are in good agreement. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Hamburg, Inst Expt Phys 2, D-22761 Hamburg, Germany. Russian Sci Ctr, Kurchatov Inst, Moscow 123182, Russia. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Jaschke, J (reprint author), Univ Hamburg, Inst Expt Phys 2, Luruper Chaussee 149, D-22761 Hamburg, Germany. NR 29 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1999 VL 155 IS 1-2 BP 189 EP 198 DI 10.1016/S0168-583X(99)00242-6 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 217BT UT WOS:000081480100026 ER PT J AU Gambhir, SS Barrio, JR Herschman, HR Phelps, ME AF Gambhir, SS Barrio, JR Herschman, HR Phelps, ME TI Assays for noninvasive imaging of reporter gene expression SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE gene imaging; gene expression; reporter genes; thymidine kinase; dopamine 2 receptor ID HERPES-SIMPLEX VIRUS; THYMIDINE KINASE GENE; GREEN FLUORESCENT PROTEIN; RADIOLABELED ANTIVIRAL DRUG; RIBOSOMAL ENTRY SITE; CYTOSINE DEAMINASE; DOPAMINE-RECEPTOR; IN-VIVO; HEPATOMA-CELLS; THERAPY AB Repeated, noninvasive imaging of reporter gene expression is emerging as a valuable tool for monitoring the expression of genes in animals and humans. Monitoring of organ/cell transplantation in living animals and humans, and the assessment of environmental, behavioral, and pharmacologic modulation of gene expression in transgenic animals should soon be possible. The earliest clinical application is likely to be monitoring human gene therapy in tumors transduced with the herpes simplex virus type 1 thymidine kinase (HSV1-tk) suicide gene. Several candidate assays for imaging reporter gene expression have been studied, utilizing cytosine deaminase (CD), HSV1-tk, and dopamine 2 receptor (D2R) as reporter genes. For the HSV1-tk reporter gene, both uracil nucleoside derivatives (e.g., 5-iodo-2'-fluoro-2'-deoxy-1-beta-D-arabinofuranosyl-5-iodouracil [FIAU] labeled with I-124, I-131) and acycloguanosine derivatives {e.g., 8-[F-18]fluoro-9-[[2-hydroxy-1-(hydroxymethyl)ethoxy]methyl]guanine (8-[F-18]-fluoroganciclovir) ([F-18]FGCV), 9-[(3-[F-18]fluoro-1-hydroxy-2-propoxy)methyl]guanine ([F-18]FHPG)} have been investigated as reporter probes. For the D2R reporter gene, a derivative of spiperone {3-(2'-[F-18]-Fluoroethyl)spiperone ([F-18]FESP)} has been used with positron emission tomography (PET) imaging. In this review, the principles and specific assays for imaging reporter gene expression are presented and discussed. Specific examples utilizing adenoviral-mediated delivery of a reporter gene as well as tumors expressing reporter genes are discussed. (C) 1999 Elsevier Science Inc. All rights reserved. C1 Univ Calif Los Angeles, Sch Med, Crunp Inst Biol Imaging, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, Dept Mol & Med Pharmacol, Div Nucl Med,Lab Struct Biol & Mol Med,DOE, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, Dept Biomath, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, Jonsson Comprehens Canc Ctr, Los Angeles, CA 90095 USA. RP Gambhir, SS (reprint author), Univ Calif Los Angeles, Sch Med, Crunp Inst Biol Imaging, A-222B CIBI,700 Westwood Plaza, Los Angeles, CA 90095 USA. NR 74 TC 169 Z9 175 U1 0 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD JUL PY 1999 VL 26 IS 5 BP 481 EP 490 DI 10.1016/S0969-8051(99)00021-9 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 219BA UT WOS:000081586800001 PM 10473186 ER PT J AU Yu, JF Yin, DZ Min, XF Guo, ZL Zhang, J Wang, YX Knapp, FF AF Yu, JF Yin, DZ Min, XF Guo, ZL Zhang, J Wang, YX Knapp, FF TI [Re-188]rhenium sulfide suspension: A potential radiopharmaceutical for tumor treatment following intra-tumor injection SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE [Re-188]rhenium sulfide; suspension; biodistribution; intra-tumor injection; tumor-inhibiting ratio ID RADIATION SYNOVECTOMY; SOMATOSTATIN ANALOG; RE-188-RC-160; RADIOTHERAPY; RHENIUM; RE-188 AB Intralesional therapy has been shown to be an effective treatment for tumors. In this study, the suitability of [Re-188]rhenium sulfide suspension for tumor treatment following intra-tumor injection was evaluated. The [Re-188]rhenium sulfide suspension was radiolabeled with Re-188 with a radiochemical yield of more than 96%. In vitro stability studies revealed that more than 99% of the Re-188 remained in sulfide form over a 3-day period. After ultrasonication for 5 or 10 min, the main particle size was 1-5 mu m. Two [Re-188]rhenium sulfide suspensions ultrasonicated for 5 and 10 min, respectively, were injected into separate group of tumor-bearing mice that were killed after specified times to compare the retention of Re-188 in tumors and the leakage to different organs by periods and organs removed to gamma counting. The mean retention percentages of Re-188 in tumors injected with suspension ultrasonicated for 5 (or 10) min were as follows: 1 h, 90.5 +/- 7.7% (83.1 +/- 13.7%); 24 h, 92.2 +/- 8.6% (83.9 +/- 9.8%); 48 h, 88.3 +/- 10.9% (80.2 +/- 3.8%); and 72 h, 91.5 +/- 7.6% (78.8 +/- 3.0%). Tumor-inhibiting ratio was 96.5%. These results demonstrated that [Re-188]rhenium sulfide suspension is an effective radiopharmaceutical for tumor treatment by intralesional therapy. (C) 1999 Elsevier Science Inc. All rights reserved. C1 Acad Sinica, Shanghai Inst Nucl Res, Shanghai 201800, Peoples R China. Shanghai Kexing Pharmaceut Corp, Shanghai, Peoples R China. Oak Ridge Natl Lab, Nucl Med Grp, Oak Ridge, TN USA. RP Yu, JF (reprint author), Acad Sinica, Inst Nucl Res, POB 800-204, Shanghai 201800, Peoples R China. NR 28 TC 5 Z9 8 U1 1 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD JUL PY 1999 VL 26 IS 5 BP 573 EP 579 PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 219BA UT WOS:000081586800012 ER PT J AU Davis, IA Glowienka, KA Boll, RA Deal, KA Brechbiel, MW Stabin, M Bochsler, PN Mirzadeh, S Kennel, SJ AF Davis, IA Glowienka, KA Boll, RA Deal, KA Brechbiel, MW Stabin, M Bochsler, PN Mirzadeh, S Kennel, SJ TI Comparison of (225) actinium chelates: Tissue distribution and radiotoxicity SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE a-particle; biodistribution; radiotoxicity; tissue toxicity; biologic effective dose; chelators ID RADIOIMMUNOTHERAPY; BI-213; COMPLEXES; AC-225 AB The biodistribution and tissue toxicity of intravenously administered 225-actinium ((225)Ac) complexed with acetate, ethylene diamine tetraacetic acid (EDTA), 1, 4, 7, 10, 13-pentaazacyclopentadecane-N, N', N ", N''', N''''-pentaacetic acid (PEPA), or the "a" isomer of cyclohexyl diethylenetriamine pentaacetic acid (CHX-DTPA), were examined. The percent of injected dose per organ and per gram of tissue for each chelate complex was determined. (225)Ac-CHX-DTPA was evaluated further for radiotoxic effects. Mice receiving greater than or equal to 185 kBq (225)Ac-CHX-DTPA suffered 100% morbidity by 5 days and 100% mortality by 8 days postinjection, and all animals evaluated had significant organ damage. The in vivo instability of the (225)Ac-CHX-DTPA complex likely allowed accumulation of free (225)Ac in organs, which resulted in tissue (C) 1999 Elsevier Science Inc. All rights reserved. pathology. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. NCI, Radioimmune & Inorgan Chem Sect, ROB, DCS,NIH, Bethesda, MD 20892 USA. IPEN CNEN SP, CN ENSP, Sao Paulo, Brazil. Univ Tennessee, Coll Vet Med, Dept Pathol, Knoxville, TN USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, Bldg 4500S,MS-6101, Oak Ridge, TN 37831 USA. EM SJ9@ornl.gov RI Boll, Rose/C-4138-2016 OI Boll, Rose/0000-0003-2507-4834 FU NHLBI NIH HHS [HL09718] NR 25 TC 28 Z9 28 U1 4 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD JUL PY 1999 VL 26 IS 5 BP 581 EP 589 DI 10.1016/S0969-8051(99)00024-4 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 219BA UT WOS:000081586800013 PM 10473198 ER PT J AU Betak, E Droste, E Mikolajewski, S Ratynski, W Rurarz, E Kempisty, T Raman, S AF Betak, E Droste, E Mikolajewski, S Ratynski, W Rurarz, E Kempisty, T Raman, S TI Activation cross sections for reactions induced by 14.7-MeV neutrons on natural calcium and enriched Ca-44 targets SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID GAMMA-RAY; RELATIVE INTENSITIES; CO-56; DECAY; GA-66 AB Using 14.7-MeV neutrons and gamma-ray spectroscopy with high-purity germanium detectors, the activation cross sections have been measured for the following nuclear reactions: (a) Ca-44(n,p)K-44, sigma = (39 +/- 4) mb; (b) Ca-44(n,np)K-43, sigma = (3.0 +/- 0.3) mb; (c) Ca-44(n,ar)Ar-41, sigma = (31 +/- 3) mb; (d) Ca-42(n,p)K-42, sigma = (138 +/- 12) mb; (e) Ca-43(n,p)K-43, sigma = (90 +/- 9) mb; and (f) Ca-48(n,2n)Ca-47, sigma = (613 +/- 60) mb. A 98.6% enriched Ca-44 target was used for reactions (a) (b) and(c) and a natural calcium target for reactions (d) (e) and (f). These cross sections have been compared with some earlier published experimental values and with some results of calculations. The latter include those based on semiempirical formulas and those given by the preequilibrium plus compound-nucleus code GNASH. When applied to reactions (a), (d), (e), and(f), this code gives cross-section values that are consistently above the measured values. C1 Slovak Acad Sci, Inst Phys, Bratislava 84228, Slovakia. Soltan Inst Nucl Studies, PL-05400 Otwock, Poland. Radioistope Ctr, PL-05400 Otwock, Poland. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Betak, E (reprint author), Slovak Acad Sci, Inst Phys, Dubravska Cesta 9, Bratislava 84228, Slovakia. NR 50 TC 11 Z9 11 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD JUL PY 1999 VL 132 IS 3 BP 295 EP 307 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 210WW UT WOS:000081128500003 ER PT J AU Morel, JE McGhee, JM AF Morel, JE McGhee, JM TI A self-adjoint angular flux equation SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The traditional second-order self-adjoint forms of the transport equation are the even- and odd-parity equations. A useful alternative to these equations exists in the form of a second-order selfadjoint equation that has the angular flux as its unknown. The numerical advantages and disadvantages of this equation are contrasted both theoretically and computationally with those of the even- and odd-parity equations. C1 Univ Calif Los Alamos Natl Lab, Transport Methods Grp, XTM, Los Alamos, NM 87545 USA. RP Morel, JE (reprint author), Univ Calif Los Alamos Natl Lab, Transport Methods Grp, XTM, POB 1663,MS D409, Los Alamos, NM 87545 USA. NR 11 TC 29 Z9 36 U1 0 U2 2 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD JUL PY 1999 VL 132 IS 3 BP 312 EP 325 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 210WW UT WOS:000081128500005 ER PT J AU Leal, LC Hermann, OW Bowman, SM Parks, CV AF Leal, LC Hermann, OW Bowman, SM Parks, CV TI Automatic rapid process for the generation of problem-dependent SAS2H/ORIGEN-S cross-section libraries SO NUCLEAR TECHNOLOGY LA English DT Article DE depletion; reactor; spent fuel AB A methodology is described that serves as art alternative to the SAS2H path of the SCALE system to generate cross sections for point-depletion calculations with the ORIGEN-S code. Automatic Rapid Processing (ARP) is an algorithm that allows the generation of cross-section libraries suitable to the ORIGEN-S code by interpolation over pregenerated SAS2H libraries. The interpolations are carried out on the following variables: burnup, enrichment, and water density. The adequacy of the methodology is evaluated by comparing measured and computed spent-fuel isotropic compositions for pressurized water reactor and boiling water reactor systems. C1 Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37831 USA. RP Leal, LC (reprint author), Oak Ridge Natl Lab, Computat Phys & Engn Div, Bldg 6011,Mail Stop 6370,POB 2008, Oak Ridge, TN 37831 USA. OI Parks, Cecil/0000-0003-0323-8447; Bowman, Stephen/0000-0002-3717-2063 NR 9 TC 5 Z9 5 U1 0 U2 2 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD JUL PY 1999 VL 127 IS 1 BP 1 EP 23 PG 23 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 209TN UT WOS:000081065100001 ER PT J AU Blackwell, BF Dowding, KJ Cochran, RJ AF Blackwell, BF Dowding, KJ Cochran, RJ TI Development and implementation of sensitivity coefficient equations for heat conduction problems SO NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS LA English DT Article ID CARBON-CARBON COMPOSITE; THERMAL-PROPERTIES; UNCERTAINTIES AB Methods are discussed for computing the sensitivity of the temperature field to changes in material properties and initial/boundary condition parameters for heat conduction problems. The most general method is to derive sensitivity equations by differentiating the energy equation with respect to the parameter of interest and solving the resulting sensitivity equations numerically. An example problem in which there are 12 parameters of interest is presented and the resulting sensitivity equations and associated boundary/initial conditions are derived. The sensitivity equations are implemented in a general-purpose unstructured-grid control-volume finite-element code. Numerical results are presented for thermal conductivity and volumetric heat capacity sensitivity coefficients for heat conduction in a 2-D orthotropic body. The numerical results are compared with Be analytical solution to demonstrate that the numerical sensitivity method is second-order accurate as the mesh is refined spatially. C1 Sandia Natl Labs, Thermal Sci Dept 9113, Engn Sci Ctr, Albuquerque, NM 87185 USA. RP Blackwell, BF (reprint author), Sandia Natl Labs, Thermal Sci Dept 9113, Engn Sci Ctr, M-S 0835, Albuquerque, NM 87185 USA. NR 19 TC 10 Z9 10 U1 1 U2 3 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 1040-7790 J9 NUMER HEAT TR B-FUND JI Numer Heat Tranf. B-Fundam. PD JUL-AUG PY 1999 VL 36 IS 1 BP 15 EP 32 PG 18 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 227CZ UT WOS:000082061900002 ER PT J AU Dowding, KJ Blackwell, BF Cochran, RJ AF Dowding, KJ Blackwell, BF Cochran, RJ TI Application of sensitivity coefficients for heat conduction problems SO NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS LA English DT Article ID CARBON-CARBON COMPOSITE; THERMAL-PROPERTIES; DESIGN AB In parameter estimation, considerable insight is provided by examining sensitivity coefficients. This article focuses on the use of sensitivity coefficients in connection with estimating thermal properties in the heat conduction equation. It is demonstrated how sensitivity coefficients are used in the design/analysis of parameter estimation experiments. A general methodology for computing sensitivity coefficients can be an important design tool in many other regards also. A control-volume, finite-element program is used to implement numerical sensitivity coefficient calculations. In this approach, general problems can be studied. Several example cases are presented to demonstrate the insight gained from sensitivity coefficients. The cases are selected from experimental studies to characterize the thermal properties of carbon-carbon composite. However, no experimental data are reported. Sensitivity coefficients show that in an experiment that is not well designed, additional materials in the experimental configuration can have a larger impact on the temperature than the material of interest. Two-dimensional configurations demonstrate that there can be isolated areas of insensitivity and the difficulty of estimating multiple parameters. C1 Sandia Natl Labs, Thermal Sci Dept 9113, Albuquerque, NM 87185 USA. RP Dowding, KJ (reprint author), Sandia Natl Labs, Thermal Sci Dept 9113, M-S 0835, Albuquerque, NM 87185 USA. NR 15 TC 12 Z9 12 U1 0 U2 1 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 1040-7790 J9 NUMER HEAT TR B-FUND JI Numer Heat Tranf. B-Fundam. PD JUL-AUG PY 1999 VL 36 IS 1 BP 33 EP 55 PG 23 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 227CZ UT WOS:000082061900003 ER PT J AU Mirkarimi, PB AF Mirkarimi, PB TI Stress, reflectance, and temporal stability of sputter-deposited Mo Si and Mo Be multilayer films for extreme ultraviolet lithography SO OPTICAL ENGINEERING LA English DT Article DE thin films; optical fabrication; stress analysis; multilayers; microlithography; extreme ultraviolet ID X-RAY MIRRORS; MOLYBDENUM SILICON MULTILAYERS; MO/SI MULTILAYERS; THIN-FILMS; PROJECTION LITHOGRAPHY; INTERFACIAL ROUGHNESS; INTRINSIC STRESS; IMAGING-SYSTEM; SCATTERING; COATINGS AB Precisely figured optics coated with high-reflectance multilayer films are an integral part of an extreme ultraviolet (EUV) projection lithography system. Since multilayer film stress deforms these precisely figured optics, it is important that this stress be characterized and that suitable methods are developed to negate the effects of the stress. However, these techniques must reduce or compensate for the effects of film stress without significantly reducing the EUV reflectivity, since the reflectivity has a strong impact on the throughput of an EUV lithography system. Different techniques for reducing multilayer stress are examined. The technique of varying the base pressure (impurity level) yielded a 10% decrease in stress with a 2% decrease in reflectance for our multilayers. A study of annealing during Mo/Si deposition is performed; a stress reduction of 70% is observed at 200 degrees C, similar to what has been found for postdeposition annealing. However, the reflectance loss was 3.9% versus 1.3% for postdeposition annealing, indicating that if annealing is performed on our films it should be done after multilayer deposition. A decrease of approximately 9% in the bilayer period thickness was observed for annealing during deposition at temperatures near 120 to 140 degrees C, much larger than the thickness changes observed during postdeposition annealing. A new athermal buffer-layer technique is developed to compensate for the effects of stress. Using this technique with amorphous silicon and Mo/Be buffer layers it is possible to obtain Mo/Be and Mo/Si multilayer films with a near zero net film stress and less than a 1% degradation in reflectivity. It is important that the multilayer coated optics are stable with time and that the stress reduction and compensation techniques do not degrade the stability. The temporal stability of 100-nm-thick Mo, Si, and Be single-layer films, Mo/Si and Mo/Be multilayer films, and films treated with various stress reduction/compensation techniques are investigated. Results are reported showing the reflectance peak wavelength to be stable to within 0.15% for both the multilayers and the stress-compensated multilayers. Therefore, stability is maintained when these buffer-layer stress compensation techniques are applied. Mo/Si multilayer films exhibit a similar to 10% short-term decrease in the stress over the first few months after deposition, but the stress stabilizes thereafter. The Mo/Si reflectance is observed to be stable to within 0.4% over a period of over 400 days. The Mo/Be multilayer film stress was stable to within about 2% over 300 days, and the reflectance was observed to decrease by about 1.5% over the same period. For Mo/Si on a Mo/Be buffer layer the stress changed from -28 to +3 MPa, and the reflectance decreased by approximately 0.4% for a period of over 300 days. For Mo/Be on an a-Si buffer layer, the stress changed from -23 to -3 MPa, and the reflectance decreased by similar to 1.8% for a period of over 300 days; this drop in reflectance is believed to be due primarily to the Mo/Be and not the addition of the buffer layer. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)01907-8]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Mirkarimi, PB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 53 TC 45 Z9 46 U1 0 U2 9 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JUL PY 1999 VL 38 IS 7 BP 1246 EP 1259 DI 10.1117/1.602170 PG 14 WC Optics SC Optics GA 216GB UT WOS:000081432100023 ER PT J AU Murphy, JB AF Murphy, JB TI Phase space conservation and selection rules for astigmatic mode converters SO OPTICS COMMUNICATIONS LA English DT Article DE phase space; mode conversion; beam quality ID WIGNER DISTRIBUTION FUNCTION; GAUSSIAN BEAMS; 2ND-ORDER MOMENTS; OPTICAL-SYSTEMS; SPOT SIZE; PROPAGATION; ORDER; DIVERGENCE AB An astigmatic mode converter consists of a pair of cylindrical lenses which, when properly located and oriented, can transform a Hermite-Gauss mode (HG(nm)) with rectangular symmetry into a Laguerre-Gauss mode (LG(nm)) with cylindrical symmetry (see E. Abramochkin, V. Volstnikov, Opt. Commun. 83 (1991) 123; M.W. Beijersbergen, L. Alien, H.E.L.O. van der Veen, J.P. Woerdman, Opt. Commun. 96 (1993) 123; M.J. Padgett, J. Arlt, N. Simpson, Am. J. Phys. 64 (1996) 77; and J. Courtial, M.J. Padgett, Opt. Commun. 159 (1999) 13). In this paper we discuss how the conservation of phase space area determines the selection rules on which mode conversions are possible. A discussion of the beam quality factor M-2 is also given for both Hermite-Gauss and Laguerre-Gauss modes. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Upton, NY 11973 USA. EM jbm@bnl.gov NR 20 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 EI 1873-0310 J9 OPT COMMUN JI Opt. Commun. PD JUL 1 PY 1999 VL 165 IS 1-3 BP 11 EP 18 DI 10.1016/S0030-4018(99)00238-2 PG 8 WC Optics SC Optics GA 212KF UT WOS:000081215300003 ER PT J AU Gertsman, VY Lin, YP Zhilyaev, AP Szpunar, JA AF Gertsman, VY Lin, YP Zhilyaev, AP Szpunar, JA TI Special grain boundaries in zirconia corrosion films SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID ZRO2; MODEL AB Transmission electron microscopy (TEM) studies of the oxide film on the surface of a zirconium alloy have been performed and the crystallography of interfaces has been analysed. Regions of a peculiar microstructure consisting almost entirely of twins have been discovered in the zirconia film. The TEM results have been analysed in conjunction with the known texture data, and the orientation relationships between monoclinic ZrO2 and the alpha-Zr substrate are discussed. Computer simulation has been performed to reveal the possible grain boundary character distributions in different regions of the film. The relevance of the results obtained to the diffusion properties of the surface zirconia layer is discussed in this paper. It is suggested that a high concentration of special grain boundaries hinders transport through the zirconia film. C1 McGill Univ, Dept Met Engn, Montreal, PQ H3A 2A7, Canada. Ontario Hydro Technol, Zirconium Met Dept, Toronto, ON M8Z 5S4, Canada. RP Gertsman, VY (reprint author), Pacific NW Natl Lab, MS P8-16, Richland, WA 99352 USA. RI Zhilyaev, Alexander/E-5624-2010; OI Zhilyaev, Alexander/0000-0002-1902-8703 NR 20 TC 15 Z9 15 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD JUL PY 1999 VL 79 IS 7 BP 1567 EP 1590 PG 24 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 215PU UT WOS:000081391200005 ER PT J AU Luo, ZP Hashimoto, H Ihara, H Iyo, A Tokiwa, K AF Luo, ZP Hashimoto, H Ihara, H Iyo, A Tokiwa, K TI Transmission electron microscopy characterization of the high-T-c superconductor HgBa2Ca3Cu4O10+delta SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID O SYSTEM; HG; HGBA2CACU2O6+DELTA; PRESSURE; CARBON; PHASE AB The structures of HgBa2Ca3Cu4O10+delta (Hg-1234) samples have been characterized by means of high-resolution electron microscopy, electron diffraction, X-ray energy-dispersive spectroscopy (XEDS) and electron-energy-loss spectroscopy (EELS) techniques. A modulated structure with a modulation vector of q = (0.036-0.048)b* + 0.5c* was found for Hg-1234. High-resolution electron microscopy on the modulated structure revealed slight displacements of atomic layers along the c direction. The anomalous contrast induced by the modulation was observed to be distributed asymmetrically between the HgOdelta, layers, leading to the breakdown of the (001) mirror symmetry of the basic structure. XEDS compositional analyses showed a depletion of mercury for the modulated Hg-1234 compared with the unmodulated Hg-1234, while EELS analysis suggested the presence of carbon in the modulated Hg-1234 phase. In addition, a side-centred ordered (Cu,Hg)-1223 phase with low mercury content was identified as one of the major impurity phases in the Hg-1234 samples. C1 Okayama Univ Sci, Okayama 700, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Luo, ZP (reprint author), Okayama Univ Sci, Okayama 700, Japan. RI Luo, Zhiping/C-4435-2014 OI Luo, Zhiping/0000-0002-8264-6424 NR 18 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 JUL PY 1999 VL 79 IS 7 BP 429 EP 439 DI 10.1080/095008399177057 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 214DX UT WOS:000081313300004 ER PT J AU Dabestani, R Ivanov, IN AF Dabestani, R Ivanov, IN TI A compilation of physical, spectroscopic and photophysical properties of polycyclic aromatic hydrocarbons SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Review ID ROOM-TEMPERATURE PHOSPHORESCENCE; UNSATURATED ORGANIC-MOLECULES; EXCITED SINGLET-STATE; SILICA GEL/AIR INTERFACE; TRIPLET ENERGY-TRANSFER; DEPENDENT MASS-SPECTRA; PHOTOELECTRON-SPECTRA; QUANTUM YIELDS; POLYNUCLEAR AROMATICS; MOUSE SKIN 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. RI ivanov, ilia/D-3402-2015 OI ivanov, ilia/0000-0002-6726-2502 NR 276 TC 200 Z9 201 U1 6 U2 47 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 JUL PY 1999 VL 70 IS 1 BP 10 EP 34 DI 10.1111/j.1751-1097.1999.tb01945.x PG 25 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 218QY UT WOS:000081564200002 ER PT J AU Toeppen, J AF Toeppen, J TI Diffraction grating SO PHOTONICS SPECTRA LA English DT Letter C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Toeppen, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAURIN PUBL CO INC PI PITTSFIELD PA BERKSHIRE COMMON PO BOX 1146, PITTSFIELD, MA 01202 USA SN 0731-1230 J9 PHOTON SPECTRA JI Photon. Spect. PD JUL PY 1999 VL 33 IS 7 BP 83 EP 83 PG 1 WC Optics SC Optics GA 214RG UT WOS:000081340900031 ER PT J AU Finnemore, DK Gray, KE Maley, MP Welch, DO Christen, DK Kroeger, DM AF Finnemore, DK Gray, KE Maley, MP Welch, DO Christen, DK Kroeger, DM TI Coated conductor development: an assessment SO PHYSICA C LA English DT Article DE ionized beam-assisted deposition; rolling-assisted biaxially textured substrate; coated conductor tapes AB This paper summarizes the current status of basic research related to the understanding and development of coated conductor tapes for use in large scale superconducting applications. It reports highlights of a workshop and discussion meeting which dealt with many of the central issues associated with both thick film deposition methods and the defects that control the critical current densities. Topics included texture control in the metal substrate, smoothing the substrate surface before the grain aligned buffer layers are deposited, deposition methods for the buffer layers, deposition methods for high performance in the superconducting layer. The ionized beam-assisted deposition (IBAD) method, and the rolling-assisted biaxially textured substrate (RABiTS) method were the primary approaches to texture control. Emphasis was placed on the use of microscopic probes to study defects and grain boundaries in order to develop a science base for the factors that determine the superconducting critical current of practical conductors. In all of the discussion, an effort was made to identify basic research that would lead to a fundamental understanding of the mechanisms at work so that we can improve processing methods and enhance performance of the superconducting tape. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Dept Phys, Ames, IA 50011 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Finnemore, DK (reprint author), Iowa State Univ, Ames Lab, Dept Phys, Ames, IA 50011 USA. RI Christen, David/A-9709-2008 NR 0 TC 70 Z9 72 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 JUL 1 PY 1999 VL 320 IS 1-2 BP 1 EP 8 DI 10.1016/S0921-4534(99)00325-1 PG 8 WC Physics, Applied SC Physics GA 219BW UT WOS:000081588900001 ER PT J AU Ozyuzer, L Yusof, Z Zasadzinski, JF Li, TW Hinks, DG Gray, KE AF Ozyuzer, L Yusof, Z Zasadzinski, JF Li, TW Hinks, DG Gray, KE TI Tunneling spectroscopy of Tl2Ba2CuO6 SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article DE high-temperature superconductivity; tunneling; superconducting gap ID ORDER-PARAMETER SYMMETRY; T-C SUPERCONDUCTORS; PAIRING SYMMETRY; GAP ANISOTROPY; BI2SR2CACU2O8+DELTA; SURFACE; YBA2CU3O7-DELTA; JUNCTIONS; JOSEPHSON; TEMPERATURE AB New results from tunneling spectroscopies on near optimally doped single crystals of Tl2Ba2CuO6 (Tl-2201) junctions are presented. The superconductor-insulator-normal metal (SIN) tunnel junctions are obtained using the point-contact technique with a Au tip. The tunneling conductances reproducibly show a sharp cusp-like subgap, prominent quasiparticle peaks with a consistent asymmetry, and weakly decreasing backgrounds. A rigorous analysis of the SIN tunneling data is performed using two different models for the d(x2-y2) (d-wave) density of states (DOS). Based on these and earlier results, the tunneling DOS of Tl-2201 has exhibited the most reproducible data that are consistent with a d-wave gap symmetry. We show that the dip feature at 26 that is clearly seen in SIN tunneling data of Bi2Sr2CaCu2O8+delta is also present in Tl-2201, but at a weaker level. The gap values for crystals with a bulk T-c = 86 K are in the range of 19-25 meV. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Ctr Sci & Technol, Superconduct & Mat Sci Div, Argonne, IL 60439 USA. Izmir Inst Technol, Dept Phys, TR-35230 Izmir, Turkey. IIT, Sci & Technol Ctr Superconduct, Chicago, IL 60616 USA. RP Ozyuzer, L (reprint author), Argonne Natl Lab, Ctr Sci & Technol, Superconduct & Mat Sci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. EM ozyuzer@anl.gov RI Ozyuzer, Lutfi/H-3142-2011 NR 30 TC 14 Z9 14 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 JUL 1 PY 1999 VL 320 IS 1-2 BP 9 EP 20 DI 10.1016/S0921-4534(99)00324-X PG 12 WC Physics, Applied SC Physics GA 219BW UT WOS:000081588900002 ER PT J AU Jacobs, K Tittonen, I Wiseman, HM Schiller, S AF Jacobs, K Tittonen, I Wiseman, HM Schiller, S TI Quantum noise in the position measurement of a cavity mirror undergoing Brownian motion SO PHYSICAL REVIEW A LA English DT Article ID FREQUENCY-MODULATION SPECTROSCOPY; GRAVITATIONAL-WAVE DETECTORS; NONDEMOLITION MEASUREMENT; RADIATION-PRESSURE; MASTER EQUATION; FORCE MICROSCOPE; MOVABLE MIRROR; INTERFEROMETER; LIGHT; REDUCTION AB We perform a quantum theoretical calculation of the noise power spectrum for a phase measurement of the light output from a coherently driven optical cavity with a freely moving rear mirror. We examine how the noise resulting from the quantum back action appears among the various contributions from other noise sources. We do not assume an ideal (homodyne) phase measurement, but rather consider phase-modulation detection, which we show has a different shot noise level. We also take into account the effects of thermal damping of the mirror, losses within the cavity, and classical laser noise, We relate our theoretical results to experimental parameters, so as to make direct comparisons with current experiments simple. We also show that in this situation, the standard Brownian motion master equation is inadequate for describing the thermal damping of the mirror, as it produces a spurious term in the steady-state phase-fluctuation spectrum. The corrected Brownian motion master equation CL. Diosi, Europhys. Lett. 22, 1 (1993)] rectifies this inadequacy. [S1050-2917(99)02107-1]. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Opt Sect, London SW7 2BZ, England. Univ Konstanz, Fak Phys, D-78457 Constance, Germany. Univ Queensland, Dept Phys, St Lucia, Qld 4072, Australia. RP Jacobs, K (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-8,MS-B285, Los Alamos, NM 87545 USA. RI Wiseman, Howard/A-7266-2008; Jacobs, Kurt/E-7049-2011; Tittonen, Ilkka/C-6649-2013 OI Wiseman, Howard/0000-0001-6815-854X; Jacobs, Kurt/0000-0003-0828-6421; Tittonen, Ilkka/0000-0002-2985-9789 NR 62 TC 50 Z9 50 U1 2 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 JUL PY 1999 VL 60 IS 1 BP 538 EP 548 DI 10.1103/PhysRevA.60.538 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 212ZF UT WOS:000081247000076 ER PT J AU Baertschy, M Rescigno, TN Isaacs, WA McCurdy, CW AF Baertschy, M Rescigno, TN Isaacs, WA McCurdy, CW TI Benchmark single-differential ionization cross section results for the s-wave model of electron-hydrogen scattering SO PHYSICAL REVIEW A LA English DT Article ID CLOSE-COUPLING METHOD; IMPACT IONIZATION; ASYMPTOTIC FORM; R-MATRIX AB Exterior complex scaling enables one to compute the outgoing wave portion of the wave function for three charged particles without explicitly imposing the asymptotic boundary condition for three-body breakup. This technique is used in connection with a high-order finite difference scheme to provide numerically accurate single-differential ionization cross sections for the Temkin-Poet (s-wave) model of e-H scattering. These benchmark values are compared with results obtained from several recent close-coupling approaches that employ pseudostates to discretize the ionization continuum, but use a strictly two-body scattering formalism. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Baertschy, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. NR 21 TC 40 Z9 40 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1999 VL 60 IS 1 BP R13 EP R16 DI 10.1103/PhysRevA.60.R13 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 212ZF UT WOS:000081247000004 ER PT J AU McQueeney, RJ Sarrao, JL Osborn, R AF McQueeney, RJ Sarrao, JL Osborn, R TI Phonon densities of states of La2-xSrxNiO4: Evidence for strong electron-lattice coupling SO PHYSICAL REVIEW B LA English DT Article ID INELASTIC NEUTRON-SCATTERING; STRIPE ORDER; CHARGE; LA2NIO4; LA1.67SR0.33NIO4; PLANE; SPECTROSCOPY; ANOMALIES; POLARONS; DYNAMICS AB The inelastic neutron-scattering spectra were measured for several Sr concentrations of polycrystalline La2-xSrxNiO4. We find that the generalized phonon density-of-states is the same for x = 0 and x = 1/8. For x = 1/3 and x = 1/2, the band of phonons corresponding to the in-plane oxygen vibrations (80-90 meV) splits into two subbands centered at 75 and 85 meV. The; lower frequency hand increases in amplitude for the x = 1/2 sample, indicating that it is directly related to the hole concentration. These changes are associated with the coupling of oxygen vibrations to doped holes which reside in the NiO2 planes and are a signature of strong electron-lattice coupling. [S0163-1829(99)02126-8]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP McQueeney, RJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Osborn, Raymond/E-8676-2011; OI Osborn, Raymond/0000-0001-9565-3140; McQueeney, Robert/0000-0003-0718-5602 NR 34 TC 20 Z9 20 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 JUL 1 PY 1999 VL 60 IS 1 BP 80 EP 83 DI 10.1103/PhysRevB.60.80 PG 4 WC Physics, Condensed Matter SC Physics GA 218KE UT WOS:000081551100021 ER PT J AU Morozov, N Bulaevskii, LN Maley, MP Coulter, JY Koshelev, AE Li, TW AF Morozov, N Bulaevskii, LN Maley, MP Coulter, JY Koshelev, AE Li, TW TI Angular dependence of c-axis magnetoresistance in Bi2Sr2CaCu2O8+delta single crystals with columnar defects SO PHYSICAL REVIEW B LA English DT Article ID JOSEPHSON PLASMA RESONANCE; DECOUPLED VORTEX LIQUID; REVERSIBLE MAGNETIZATION; PHASE COHERENCE; SUPERCONDUCTORS; TRANSITION; DISSIPATION AB We measured the angular dependence of the c-axis magnetoresistance rho(c)(B) of Bi2Sr2CaCuO8+delta irradiated with heavy ions. At temperatures near 69 K the scaling of rho(c)(B) with the c-axis magnetic field component B, is broken and the in-plane field, B-parallel to, affects rho(c). At this temperature, at a specific field B(cr)approximate to B-Phi/2, magnetoresistance becomes independent of field orientation. This crossing point allows us to estimate the correlation length L of pancake positions along the c axis. We find L/s similar to 100 at B = B-cr, where s is the interlayer spacing. This provides evidence of strong enhancement of pancake alignment in the vortex liquid in crystals with columnar defects. [S00163-1829(99)14925-7]. C1 Univ Calif Los Alamos Natl Lab, MST, STC, Los Alamos, NM 87545 USA. Argonne Natl Lab, MSD, Argonne, IL 60439 USA. RP Morozov, N (reprint author), Univ Calif Los Alamos Natl Lab, MST, STC, MS-K763, Los Alamos, NM 87545 USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 18 TC 5 Z9 5 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 1 BP 96 EP 99 DI 10.1103/PhysRevB.60.96 PG 4 WC Physics, Condensed Matter SC Physics GA 218KE UT WOS:000081551100025 ER PT J AU Salem-Sugui, S Ghivelder, L Friesen, M Moloni, K Veal, B Paulikas, P AF Salem-Sugui, S Ghivelder, L Friesen, M Moloni, K Veal, B Paulikas, P TI Temperature dependence of the second magnetization peak in a deoxygenated YBa2Cu3O6.65 single crystal SO PHYSICAL REVIEW B LA English DT Article ID ANOMALOUS MAGNETIZATION; II SUPERCONDUCTORS; REVERSIBLE MAGNETIZATION; YBA2CU3O7-DELTA CRYSTALS; IRREVERSIBILITY LINE; PINNING MECHANISMS; HYSTERESIS-LOOP; CU-O; OXYGEN; CROSSOVER AB We report on magnetic measurements carried out in a YBa2Cu3O6.65, deoxygenated single crystal with superconducting transition temperature T-c= 62.5 K. The so-called fishtail or second magnetization peak (H-p) has been observed in magnetization curves from 60 K down to 1.8 K. In the region 6 I(K insulator transition in (ET)(2)(ReO4) is a weak structural modification in which anion reordering plays a minimal role. Correlation effects id this set of compounds are important, suggesting that a Hubbard gap picture may be appropriate for interpreting the low-lying electronic structure in these organic molecular solids. [S0163-1829(99)01326-0]. C1 SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Baker, SM (reprint author), SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. RI Zhu, Zhengtao/A-1633-2009 OI Zhu, Zhengtao/0000-0002-9311-2110 NR 50 TC 6 Z9 6 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 2 BP 931 EP 941 DI 10.1103/PhysRevB.60.931 PG 11 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800034 ER PT J AU Balbach, JJ Conradi, MS Barnes, RG Sibirtsev, DS Skripov, AV AF Balbach, JJ Conradi, MS Barnes, RG Sibirtsev, DS Skripov, AV TI Nuclear magnetic resonance study of the low-temperature localized H(D) motion in alpha-ScHx(D-x): Isotope effects SO PHYSICAL REVIEW B LA English DT Article ID METAL-HYDROGEN SYSTEMS; SCANDIUM; DIFFUSION; TRANSITION; RELAXATION; DEUTERIUM; PROTON; ATOMS AB Nuclear magnetic resonance measurements of the (SC)-S-45, H-1 and D-2 spin-lattice relaxation rates in the solid solutions alpha-ScHx (x=0, 0.11, and 0.27) and alpha-ScDx (x=0.05 and 0.22) have been performed over the temperature range 4.2-294 K. For the hydrided and deuterided samples we have found pronounced deviations of the (SC)-S-45 relaxation rate measured at 86.2 MHz from the Korringa behavior in the range 30-180 K. The excess (SC)-S-45 relaxation rate displays a peak near 100 K in alpha-ScHx and near 110-140 K in alpha-ScDx, resulting from the quadrupole interaction modulated by fast localized hopping of H(D) atoms. The amplitude of the (SC)-S-45 relaxation rate measured at 86.2 MHz from the Korringa behavior in the range 30-180 K. The excess (SC)-S-45 relaxation rate peak in the deuterided samples is found to be much higher than in the hydrided samples with comparable hydrogen content. This unusual isotope effect indicates that the fraction of D atoms participating in the fast localized motion in alpha-ScDx is approximately six times as large as the corresponding fraction of H atoms in alpha-ScHx. The results of our measurements of the H-1 and D-2 relaxation rates are consistent with this conclusion. The strong effect of H<-> D substitution on the fraction of atoms involved in the localized hopping should be accounted for in any microscopic model of hydrogen motion in Sc. [S0163-1829(99)15725-4]. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Russian Acad Sci, Urals Branch, Inst Met Phys, Ekaterinburg 620219, Russia. RP Balbach, JJ (reprint author), Washington Univ, Dept Phys, St Louis, MO 63130 USA. RI Skripov, Alexander/K-4525-2013 OI Skripov, Alexander/0000-0002-0610-5538 NR 22 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 JUL 1 PY 1999 VL 60 IS 2 BP 966 EP 971 DI 10.1103/PhysRevB.60.966 PG 6 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800038 ER PT J AU Jaime, M Lin, P Chun, SH Salamon, MB Dorsey, P Rubinstein, M AF Jaime, M Lin, P Chun, SH Salamon, MB Dorsey, P Rubinstein, M TI Coexistence of localized and itinerant carriers near T-C in calcium-doped manganites SO PHYSICAL REVIEW B LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; FERROMAGNETIC TRANSITION; POLARON CROSSOVER; PEROVSKITE; LA1-XCAXMNO3; RESISTIVITY; TRANSPORT; LA0.67CA0.33MNO3; LA2/3CA1/3MNO3; LA1-XSRXMNO3 AB We explore the possibility that polaronic distortions in the paramagnetic phase of La0.67Ca0.33MnO3 manganites persist in the ferromagnetic phase by considering the observed electrical resistivity to arise from coexisting field- and temperature-dependent polaronic and band-electron fractions. We use an effective medium approach to compute the total resistivity of the two-component system, and find that a limit with low percolation threshold explains the data rather well. To test the validity of this model, we apply it to the thermoelectric coefficient. We propose a plausible mean-field model that reproduces the essential features of a microscopic model and provides a comparison with the experimental mixing fraction, as well as the magnetization and magnetic susceptibility. C1 Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Jaime, M (reprint author), Univ Calif Los Alamos Natl Lab, MSK764, Los Alamos, NM 87545 USA. RI Jaime, Marcelo/F-3791-2015; OI Jaime, Marcelo/0000-0001-5360-5220; Chun, Seung-Hyun/0000-0001-8397-4481 NR 37 TC 161 Z9 163 U1 1 U2 13 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 2 BP 1028 EP 1032 DI 10.1103/PhysRevB.60.1028 PG 5 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800047 ER PT J AU Vaknin, D Zarestky, JL Ostenson, JE Chakoumakos, BC Goni, A Pagliuso, PJ Rojo, T Barberis, GE AF Vaknin, D Zarestky, JL Ostenson, JE Chakoumakos, BC Goni, A Pagliuso, PJ Rojo, T Barberis, GE TI Weakly (x=0) and randomly (x=0.033) coupled Ising antiferromagnetic planes in (Li1-3xFex)NiPO4 compounds SO PHYSICAL REVIEW B LA English DT Article ID CRITICAL-BEHAVIOR; LI3IN2(PO4)3; PHOSPHATE; LI-7 AB Neutron diffraction and magnetic susceptibility studies of (Li1-3xFex)NiPO4 (x = 0 and x = 0.033) compounds reveal remarkable differences between the magnetic properties of pure LiNiPO4 and those of its lightly iron-doped derivative. The spin system associated with the Ni2+ ions (S = 1) in the pure compound undergoes a collinear antiferromagnetic ordering at T-N = 19.1 +/- 0.5 K, with the characteristics of weakly coupled two-dimensional (2D) Ising square planes. By contrast, randomly intercalated iron spins (in Li sites) between Ni2+ planes comprise a spin-glass-like subsystem which, despite their minute amount, drives the antiferromagnetic transition to higher temperatures T-N= 25.2 +/- 0.5 K; and significantly modifies the critical behavior of the 2D Ni2+ system. It is argued that the doped compound can serve as a model system for studying the randomly coupled planar Ising model. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Basque Country, Euskal Herriko Unibertsitatea, Dept Quim Inorgan ISEM, Fac Ciencias, E-48080 Bilbao, Spain. Univ Estadual Campinas, Inst Fis, BR-13087970 Campinas, SP, Brazil. RP Vaknin, D (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Rojo, Teofilo/B-5197-2015; Chakoumakos, Bryan/A-5601-2016; Vaknin, David/B-3302-2009; Inst. of Physics, Gleb Wataghin/A-9780-2017 OI Rojo, Teofilo/0000-0003-2711-8458; Chakoumakos, Bryan/0000-0002-7870-6543; Vaknin, David/0000-0002-0899-9248; NR 39 TC 38 Z9 38 U1 0 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 2 BP 1100 EP 1110 DI 10.1103/PhysRevB.60.1100 PG 11 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800054 ER PT J AU Mints, RG Kogan, VG AF Mints, RG Kogan, VG TI Josephson junction between anisotropic superconductors SO PHYSICAL REVIEW B LA English DT Article ID TORQUE MAGNETOMETRY AB Sin-Gordon equation for Josephson junctions with arbitrary misaligned anisotropic banks is derived. As an application, the problem of Josephson vortices at twin planes of a Y-Ba-Cu-O-like material is considered. It is shown that for an arbitrary orientation of these vortices relative to the crystal axes of the banks, the junctions should experience a mechanical torque which is evaluated. This torque and its angular dependence may, in principle, be measured in small fields, since the Aux penetration into twinned crystals begins with nucleation of Josephson vortices at twin planes. [S0163-1829(99)08925-0]. C1 Tel Aviv Univ, Sch Phys & Astron, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Iowa State Univ, DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Mints, RG (reprint author), Tel Aviv Univ, Sch Phys & Astron, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. RI Mints, Roman/A-5091-2008 NR 7 TC 2 Z9 2 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 2 BP 1394 EP 1399 DI 10.1103/PhysRevB.60.1394 PG 6 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800088 ER PT J AU Wakimoto, S Shirane, G Endoh, Y Hirota, K Ueki, S Yamada, K Birgeneau, RJ Kastner, MA Lee, YS Gehring, PM Lee, SH AF Wakimoto, S Shirane, G Endoh, Y Hirota, K Ueki, S Yamada, K Birgeneau, RJ Kastner, MA Lee, YS Gehring, PM Lee, SH TI Observation of incommensurate magnetic correlations at the lower critical concentration for superconductivity in La2-xSrxCuO4 (x=0.05) SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; SPIN AB Neutron-scattering experiments have been performed on lightly doped La2-xSrxCuO4 single crystals in both the insulating (x = 0.03,0.04,0.05) and superconducting (x = 0.06) regions. Elastic magnetic peaks are observed at low temperatures in all samples with the maximum peak linewidth occurring at the critical concentration x,= 0.05. Incommensurate peaks are observed only at x = 0.05, the positions of which are rotated by 45 degrees in reciprocal space about (pi,pi) from those observed for x greater than or equal to 0.06 in the superconducting phase. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Wakimoto, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Hirota, Kazuma/C-6797-2008; Yamada, Kazuyoshi/C-2728-2009 NR 13 TC 149 Z9 149 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1999 VL 60 IS 2 BP R769 EP R772 DI 10.1103/PhysRevB.60.R769 PG 4 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800013 ER PT J AU Engel, J Bender, M Dobaczewski, J Nazarewicz, W Surman, R AF Engel, J Bender, M Dobaczewski, J Nazarewicz, W Surman, R TI beta decay rates of r-process waiting-point nuclei in a self-consistent approach SO PHYSICAL REVIEW C LA English DT Article ID GAMOW-TELLER STRENGTH; GROUND-STATE PROPERTIES; MEAN-FIELD DESCRIPTION; EFFECTIVE FORCES; HALF-LIVES; SKYRMES INTERACTION; SPHERICAL NUCLEI; DRIP-LINE; ISOTOPES; PARAMETRIZATION AB beta decay rates for spherical neutron-rich r-process waiting-point nuclei are calculated within a fully self-consistent quasiparticle random-phase approximation, formulated in the Hartree-Fock-Bogoliubov canonical single-particle basis. The same Skyrme force is used everywhere in the calculation except in the proton-neutron particle-particle channel. where a finite-range force is consistently employed. In all but the heaviest nuclei, the resulting half-lives are usually shorter by factors of 2 to 5 than those of calculations that ignore the proton-neutron particle-particle interaction. The shorter half-lives alter predictions for the abundance distribution of r-process elements and for the time it takes to synthesize them. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Engel, J (reprint author), Univ N Carolina, Dept Phys & Astron, CB 3255,Phillips Hall, Chapel Hill, NC 27599 USA. RI Bender, Michael/B-9004-2009 NR 63 TC 150 Z9 154 U1 0 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 JUL PY 1999 VL 60 IS 1 AR 014302 DI 10.1103/PhysRevC.60.014302 PG 12 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000011 ER PT J AU Forest, JL Pandharipande, VR Arriaga, A AF Forest, JL Pandharipande, VR Arriaga, A TI Quantum Monte Carlo studies of relativistic effects in light nuclei SO PHYSICAL REVIEW C LA English DT Article ID TRITON BINDING-ENERGY; FEW-BODY NUCLEI; SCATTERING; RETARDATION; EQUATION; SYSTEMS; STATES; HE-4; H-3 AB Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials, and their boost corrections. In this work we use the variational Monte Carlo method to study two kinds of relativistic effects in H-3 and He-4, using relativistic Hamiltonians. The first is due to the nonlocalities in the relativistic kinetic energy and relativistic one-pion exchange potential (OPEP), and the second is from boost interaction. The OPEP contribution is reduced by similar to 15% by the relativistic nonlocality, which may also have significant effects on pion exchange currents. However, almost all of this reduction is canceled by changes in the kinetic energy and other interaction terms, and the total effect of the nonlocalities on the binding energy is very small. The boost interactions, on the other hand, give repulsive contributions of similar to 0.4 (1.9) MeV in H-3 (He-4) and account for similar to 37% of the phenomenological part of the three-nucleon interaction needed in the nonrelativistic Hamiltonians. The wave functions of nuclei are not significantly changed by these effects. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Lisbon, Ctr Fis Nucl, P-1699 Lisbon, Portugal. Univ Lisbon, Fac Ciencias, Dept Fis, P-1700 Lisbon, Portugal. RP Forest, JL (reprint author), Jefferson Lab Theory Grp, 12000 Jefferson Ave, Newport News, VA 23606 USA. EM jforest@jlab.org; vijay@rsml.physics.uiuc.edu; arriaga@alf1.cii.fc.ul.pt RI Arriaga, Ana/N-2369-2015 OI Arriaga, Ana/0000-0002-8113-7425 NR 42 TC 24 Z9 25 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 JUL PY 1999 VL 60 IS 1 AR 014002 DI 10.1103/PhysRevC.60.014002 PG 16 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000008 ER PT J AU Hartley, DJ Riedinger, LL Jin, HQ Reviol, W Smith, BH Galindo-Uribarri, A Sarantites, DG LaFosse, DR Wilson, JN Mullins, SM AF Hartley, DJ Riedinger, LL Jin, HQ Reviol, W Smith, BH Galindo-Uribarri, A Sarantites, DG LaFosse, DR Wilson, JN Mullins, SM TI Rotational structures in La-125 and alignments in A approximate to 130 nuclei SO PHYSICAL REVIEW C LA English DT Article ID BAND-CROSSING FREQUENCIES; HIGH-SPIN STATES; SHAPE CHANGES; MASS REGION; NEUTRON; SPECTROSCOPY; PROTON; DEFORMATIONS; ENERGIES; PROLATE AB High-spin states in La-125 have been populated using the Mo-94(Ca-40,2 alpha p) reaction at a beam energy of 180 MeV. Four of the five previously known rotational structures have been extended to higher spin (I less than or equal to 71/2) and excitation energy. In addition, three new sequences were observed, two of which form a strongly-coupled band. This latter structure is likely based on the [404]9/2 proton orbital, which is associated with strong deformation driving behavior in nearby Pr and Pm nuclei. A systematic examination of the crossing frequencies based on the rotational alignment of h(11/2) protons and h(11/2) neutrons is also presented. The dependence of the crossing frequencies on deformation and Fermi surface can be inferred based on experimental observation and evidence for reduced proton and possibly neutron pairing fields is presented. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Australian Natl Univ, Dept Nucl Phys, Canberra, ACT 0200, Australia. RP Hartley, DJ (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 47 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1999 VL 60 IS 1 AR 014308 PG 11 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000017 ER PT J AU Klein, SR Nystrand, J AF Klein, SR Nystrand, J TI Exclusive vector meson production in relativistic heavy ion collisions SO PHYSICAL REVIEW C LA English DT Article ID PHOTON; PHOTOPRODUCTION; PHYSICS AB Exclusive vector meson production reactions such as Au+Au-->Au+Au+V, where V=rho, omega, phi, or J/psi, can proceed through photon-Pomeron and photon-meson interactions. Photons from the electromagnetic field of one nucleus interact coherently with the other nucleus. Photonuclear cross sections an scaled from gamma p data and convoluted with the photon spectrum to find the exclusive rates. The cross sections at the RHIC and LHC heavy ion colliders are huge, 10% of the total hadronic cross section at RHIC and 50% at LHC. These accelerators may be useful as vector meson factories. With iodine beams at RHIC, 640 rho are produced each second( 10(10)/yr); with calcium at the LHC the rate is 240 kHz. The phi rates are 39 Hz at RHIC and 15 kHz at LHC, while the J/psi rate is 0.3 Hz at RHIC and 780 Hz at the LHC. Because of the coherent couplings, the reactions kinematics are similar to coherent two-photon interactions; we discuss the interplay between the two reactions. [S0556-2813(99)00207-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Klein, SR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 30 TC 144 Z9 144 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 JUL PY 1999 VL 60 IS 1 AR 014903 DI 10.1103/PhysRevC.60.014903 PG 8 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000034 ER PT J AU Kondev, FG Riley, MA Hartley, DJ Brown, TB Laird, RW Lively, M Pfohl, J Sheline, RK Paul, ES Joss, DT Nolan, PJ Shepherd, SL Clark, RM Fallon, P Sarantites, DG Devlin, M LaFosse, DR Lerma, F Wadsworth, R Hibbert, IM O'Brien, NJ Simpson, J Archer, DE AF Kondev, FG Riley, MA Hartley, DJ Brown, TB Laird, RW Lively, M Pfohl, J Sheline, RK Paul, ES Joss, DT Nolan, PJ Shepherd, SL Clark, RM Fallon, P Sarantites, DG Devlin, M LaFosse, DR Lerma, F Wadsworth, R Hibbert, IM O'Brien, NJ Simpson, J Archer, DE TI Differential quadrupole moment measurements of the 1/2(+)[660] (i(13/2)) neutron intruder band in Nd-133 and Nd-135 SO PHYSICAL REVIEW C LA English DT Article ID HIGHLY DEFORMED BANDS; LIFETIME MEASUREMENTS; SUPERDEFORMED BAND; MASS REGION; SPIN STATES; MINIMUM; DEFORMATIONS; SPECTROSCOPY; ENERGIES; CE-133 AB Quadrupole moment measurements of the 1/2(+)[660] (i(13/2)) bands in Nd-133 (N = 73) and Nd-135 (N = 75) were performed using the Doppler-shift attenuation method. These results, coupled with the previously measured Q(0) for the same configuration in Nd-137 (N = 77), clearly demonstrate a trend of decreasing quadrupole deformation with increasing neutron number. The larger quadrupole moment in Nd-133 compared with that in Nd-135 and Nd-137 offers evidence for the role played by the large shell gap at N = 72 for beta(2) similar to 0.35-0.40 in stabilizing the shape at enhanced deformation. The comparison of results from gating below and above the level of interest provides information on the time scale of the sidefeeding contributions to highly deformed structures in the A similar to 130 region. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England. SERC, Daresbury Lab, CLRC, Warrington WA4 4AD, Cheshire, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kondev, FG (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RI Devlin, Matthew/B-5089-2013 OI Devlin, Matthew/0000-0002-6948-2154 NR 31 TC 24 Z9 24 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 JUL PY 1999 VL 60 IS 1 AR 011303 DI 10.1103/PhysRevC.60.011303 PG 5 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000003 ER PT J AU Myers, WD Swiatecki, WJ AF Myers, WD Swiatecki, WJ TI Thomas-Fermi fission barriers SO PHYSICAL REVIEW C LA English DT Article ID MODEL AB Using the self-consistent Thomas-Fermi model from our earlier work, backed by the liquid-drop-model scaling rule for fission barriers, we have constructed a simple algebraic equation for Thomas-Fermi fission barriers. The equation is accurate for proton numbers greater than about 70 and for neutron numbers up to at least 20 units on either side of beta stability. This has made it possible to make a comprehensive comparison of the Thomas-Fermi theory with 120 measured fission barriers. [S0556-2813(99)05507-7]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Myers, WD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 13 TC 104 Z9 104 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 JUL PY 1999 VL 60 IS 1 AR 014606 DI 10.1103/PhysRevC.60.014606 PG 4 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000031 ER PT J AU Ramsey-Musolf, MJ AF Ramsey-Musolf, MJ TI Low-energy parity-violation and new physics SO PHYSICAL REVIEW C LA English DT Article ID INELASTIC ELECTRON-SCATTERING; NEUTRAL-CURRENT; P(P)OVER-BAR COLLISIONS; POLARIZED ELECTRONS; NUCLEAR-STRUCTURE; NON-CONSERVATION; ROOT-S=1.8 TEV; GAUGE BOSONS; NONCONSERVATION; CESIUM AB The new physics sensitivity of a variety of low-energy parity-violating (PV) observables is analyzed. A comparison is made between atomic PV for a single isotope, atomic PV using isotope ratios, and PV electron-hadron and electron-electron scattering. The complementarity among these observables, as well as with high-energy processes, is emphasized. Theoretical uncertainties entering the interpretation of low-energy measurements are discussed. [S0556-2813(99)03207-0]. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. Thomas Jefferson Natl Lab, Theory Grp, Newport News, VA 23606 USA. RP Ramsey-Musolf, MJ (reprint author), Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. NR 83 TC 78 Z9 78 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 JUL PY 1999 VL 60 IS 1 AR 015501 DI 10.1103/PhysRevC.60.015501 PG 18 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000040 ER PT J AU Reinhard, PG Dean, DJ Nazarewicz, W Dobaczewski, J Maruhn, JA Strayer, MR AF Reinhard, PG Dean, DJ Nazarewicz, W Dobaczewski, J Maruhn, JA Strayer, MR TI Shape coexistence and the effective nucleon-nucleon interaction SO PHYSICAL REVIEW C LA English DT Article ID RELATIVISTIC MEAN-FIELD; GROUND-STATE PROPERTIES; NEUTRON-RICH NUCLEI; GENERATOR-COORDINATE METHOD; N = 20; SHELL-MODEL; EFFECTIVE FORCES; DRIP-LINE; SKYRMES INTERACTION; SELF-CONSISTENT AB The phenomenon of shape coexistence is discussed within the self-consistent Hartree-Fock method and the nuclear shell model. The occurrence of the coexisting configurations with different intrinsic shapes is traced back to the properties of the effective Hamiltonian. C1 Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Univ Erlangen Nurnberg, Inst Theoret Phys, D-91058 Erlangen, Germany. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. Goethe Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany. RP Reinhard, PG (reprint author), Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, POB 2008, Oak Ridge, TN 37831 USA. NR 90 TC 239 Z9 240 U1 2 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 EI 1089-490X J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1999 VL 60 IS 1 AR 014316 DI 10.1103/PhysRevC.60.014316 PG 20 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000025 ER PT J AU Rykaczewski, K Batchelder, JC Bingham, CR Davinson, T Ginter, TN Gross, CJ Grzywacz, R Karny, M MacDonald, BD Mas, JF McConnell, JW Piechaczek, A Slinger, RC Toth, KS Walters, WB Woods, PJ Zganjar, EF Barmore, B Ixaru, LG Kruppa, AT Nazarewicz, W Rizea, M Vertse, T AF Rykaczewski, K Batchelder, JC Bingham, CR Davinson, T Ginter, TN Gross, CJ Grzywacz, R Karny, M MacDonald, BD Mas, JF McConnell, JW Piechaczek, A Slinger, RC Toth, KS Walters, WB Woods, PJ Zganjar, EF Barmore, B Ixaru, LG Kruppa, AT Nazarewicz, W Rizea, M Vertse, T TI Proton emitters Ho-140 and Ho-141: Probing the structure of unbound Nilsson orbitals SO PHYSICAL REVIEW C LA English DT Article ID DEFORMED-NUCLEI; EXCITATION-ENERGIES; RADIOACTIVITY; DECAY; DEFORMATIONS AB Two new proton emitting states in the deformed nuclei Ho-140 (E-p = 1086 +/- 10 keV, T-1/2 = 6+/-3 ms) and Ho-141m (E-p = 1230+/-20 keV, T-1/2 = 8+/-3 mu s) have been identified. Experimental data are interpreted using the coupled-channels Schrodinger equation with outgoing wave boundary conditions. The observed resonances are discussed in terms of deformed single-proton orbitals close to the Z = 67 Fermi level. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Fac Phys, PL-00681 Warsaw, Poland. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. Univ Edinburgh, Edinburgh EH9 3JZ, Midlothian, Scotland. Vanderbilt Univ, Nashville, TN 37235 USA. Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst Phys & Nucl Engn Horia Hulubei, College Pk, MD 20742 USA. Hungarian Acad Sci, Inst Nucl Res, H-4001 Debrecen, Hungary. Univ Maryland, College Pk, MD 20742 USA. RP Rykaczewski, K (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RI ixaru, liviu/C-1238-2011 NR 36 TC 90 Z9 90 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1999 VL 60 IS 1 AR 011301 DI 10.1103/PhysRevC.60.011301 PG 5 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000001 ER PT J AU Toth, KS Bingham, CR Batchelder, JC Brown, LT Conticchio, LF Davids, CN Irvine, RJ Seweryniak, D Moltz, DM Walters, WB Wauters, J Zganjar, EF AF Toth, KS Bingham, CR Batchelder, JC Brown, LT Conticchio, LF Davids, CN Irvine, RJ Seweryniak, D Moltz, DM Walters, WB Wauters, J Zganjar, EF TI alpha-decay rates of Pb-180,Pb-182,Pb-184 and the Z=82 shell closure SO PHYSICAL REVIEW C LA English DT Article ID ATOMIC MASS EVALUATION; ISOTOPES; IDENTIFICATION; SEPARATION; ENERGIES; PO-190; NUCLEI; PB-190 AB The proton-rich isotopes Pb-180, Pb-182 and Pb-184 were produced in Mo-92 bombardments of Zr-90, Zr-92, and Zr-94, respectively, and their alpha-decay properties were investigated with the use of a fragment mass analyzer and a double-sided Si strip detector. These data yielded unambiguous identifications of Pb-180 and Pb-182 and half-lives for all three Pb nuclei that are mon precise than previously available values. An examination of alpha reduced widths in the Pb mass region leads to the conclusion that the Z = 82 shell gap is greatly reduced for neutron numbers midway between 82 and 126. Available mass data, manifested in Delta Q(alpha) values and two-proton separation energies of even-even nuclei with the same neutron numbers, support this conclusion. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Oak Ridge Associated Univ, UNIRIB, Oak Ridge, TN 37831 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Edinburgh, Edinburgh EH9 3JZ, Midlothian, Scotland. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Toth, KS (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 29 TC 35 Z9 35 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1999 VL 60 IS 1 AR 011302 DI 10.1103/PhysRevC.60.011302 PG 5 WC Physics, Nuclear SC Physics GA 216ZU UT WOS:000081475000002 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, H Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM 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 Jaques, J Jerger, SA Jesik, R Joff-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kelly, ML Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Loken, SC Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Moromisato, J Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oliveira, E Oltman, E Oshima, N Owen, D Padley, P Para, A Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, H Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, H Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, H Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM 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 Jaques, J Jerger, SA Jesik, R Joff-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kelly, ML Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Loken, SC Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Moromisato, J Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oliveira, E Oltman, E Oshima, N Owen, D Padley, P Para, A Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, H Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, H Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Measurement of the top quark pair production cross section in p(p)over-bar collisions using multijet final states SO PHYSICAL REVIEW D LA English DT Article ID COLLIDER DETECTOR; ROOT-S=1.8 TEV; JETS; MASS; COLLABORATION; FERMILAB; EVENTS AB We have studied production using multijet final states in collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity of 110.3 pb(-1). Each of the top quarks with these final states decays exclusively to a bottom quark and a W boson, with the W bosons decaying into quark-antiquark pairs. The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the It production cross section, and yields a cross section of 7.1+/-2.8 (stat)+/- 1.5 (syst) pb, assuming a top quark mass of 172.1 GeV/c(2). Combining this result with previous DO measurements, where one or both of the W bosons decay leptonically, gives a production cross section of 5.9+/-1.2 (stat)+/-1.1 (syst) ph. [S0556-2821(99)03607-3]. C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Univ Los Andes, Bogota, Colombia. CEA Saclay, DAPNIA, Serv Phys Particules, Gif Sur Yvette, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Arizona, Tucson, AZ 85721 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), NYU, New York, NY 10003 USA. RI Alves, Gilvan/C-4007-2013; Kim, Sun Kee/G-2042-2015; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Chekulaev, Sergey/O-1145-2015 OI Kim, Sun Kee/0000-0002-0013-0775; Aihara, Hiroaki/0000-0002-1907-5964; Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; NR 35 TC 16 Z9 16 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 012001 PG 26 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000004 ER PT J AU Balitsky, I AF Balitsky, I TI Factorization and high-energy effective action SO PHYSICAL REVIEW D LA English DT Article ID WEIZSACKER-WILLIAMS FIELDS; QUANTUM CHROMODYNAMICS; OPERATOR EXPANSION; NUCLEUS COLLISIONS; GLUON PRODUCTION; QCD; SCATTERING; APPROXIMATION; POMERON AB I demonstrate that the amplitude for high-energy scattering can be factorized as a convolution of the contributions due to fast and slow fields. The fast and slow fields interact by means of Wilson-line operators-infinite gauge factors ordered along the straight line. The resulting factorization formula gives a starting point for a new approach to the effective action for high-energy scattering in QCD. [S0556-2821(99)03413-X]. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. RP Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. EM balitsky@jlab.org NR 24 TC 226 Z9 226 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 014020 DI 10.1103/PhysRevD.60.014020 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000031 ER PT J AU Boer, D AF Boer, D TI Investigating the origins of transverse spin asymmetries at BNL RHIC SO PHYSICAL REVIEW D LA English DT Article ID DRELL-YAN PROCESS; DEEP-INELASTIC-SCATTERING; HADRON-HADRON SCATTERING; HIGHER-TWIST; POLARIZED ANTIPROTONS; QUANTUM CHROMODYNAMICS; E(+)E(-) ANNIHILATION; ANGULAR-DISTRIBUTIONS; PI(0) PRODUCTION; COUNTER-EXAMPLE AB We discuss possible origins of transverse spin asymmetries in hadron-hadron collisions and propose an explanation in terms of a chiral-odd T-odd distribution function with intrinsic transverse momentum dependence, which would signal a correlation between the transverse spin and the transverse momentum of quarks inside an unpolarized hadron. We will argue that despite its conceptual problems, it can account for single spin asymmetries, for example in pp dagger-->pi X, and at the same time for the large cos 2 phi asymmetry in the unpolarized Drell-Yan cross section, which still lacks understanding. We use the latter asymmetry to arrive at a crude model for this function and show explicitly how it relates unpolarized and polarized observables in the Drell-Yan process, as could be measured with the proton-proton collisions at BNL RHIC. Moreover, it would provide an alternative method of accessing the transversity distribution function h(1). For future reference we also list the complete set of azimuthal asymmetries in the unpolarized and polarized Drell-Yan process at leading order involving T-odd distribution functions with intrinsic transverse momentum dependence. [S0556-2821(99)04213-7]. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Boer, D (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RI Boer, Daniel/B-3493-2015 OI Boer, Daniel/0000-0003-0985-4662 NR 56 TC 212 Z9 213 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 014012 DI 10.1103/PhysRevD.60.014012 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000023 ER PT J AU Chua, CK He, XG Hou, WS AF Chua, CK He, XG Hou, WS TI CP violating b -> s gamma decay in supersymmetric models SO PHYSICAL REVIEW D LA English DT Article ID SEMILEPTONIC BRANCHING RATIO; RADIATIVE B-DECAYS; STANDARD-MODEL; PROCESS B->S-GAMMA; PHYSICS; CONSTRAINTS AB Supersymmetric models with nonuniversal squark masses can enrich the chiral structure and CP violating phenomena in b-->s gamma decays. Direct CP violation in b-->s gamma decay, mixing induced CP violation in radiative B-d,B-s decays (such as B-s-->phi gamma and B-d-->K-1,K-2*gamma), and Lambda polarization in Lambda(b) --> Lambda(gamma) decay can be substantially different from the standard model. Future experiments at e(+)e(-) and hadronic B factories will give important information on the underlying couplings for radiative b decays. [S0556-2821(99)05509-5]. C1 Natl Taiwan Univ, Dept Phys, Taipei 10764, Taiwan. Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Chua, CK (reprint author), Natl Taiwan Univ, Dept Phys, Taipei 10764, Taiwan. RI He, Xiao-Gang/C-8894-2013; He, Xiao-Gang/P-2242-2015 NR 21 TC 54 Z9 54 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 014003 DI 10.1103/PhysRevD.60.014003 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000014 ER PT J AU Dawson, S Reina, L AF Dawson, S Reina, L TI Associated Higgs boson production in the MSSM SO PHYSICAL REVIEW D LA English DT Article ID STANDARD MODEL; MASS AB We investigate the inclusive production of the Higgs bosons of the minimal supersymmetric model with a heavy quark pair (t (t) over bar and b (b) over bar), in e(+)e(-) collisions at high energies, root s = 500 GeV and root s = 1 TeV. The O(alpha(s)) QCD radiative corrections are included and the dependence of the production rates on the parameters of the MSSM is explored. The associated production of a Higgs boson with a b (b) over bar pair receives large resonant contributions and can have a significant rate. [S0556-2821(99)05013-4]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Dawson, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 19 TC 31 Z9 31 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 015003 DI 10.1103/PhysRevD.60.015003 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000037 ER PT J AU Ellis, RK Veseli, S AF Ellis, RK Veseli, S TI Strong radiative corrections to Wb(b)over-bar production in p(p)over-bar collisions SO PHYSICAL REVIEW D LA English DT Article ID ONE-LOOP AMPLITUDES; HADRON-COLLISIONS; CROSS-SECTIONS; HIGGS-BOSON; QCD; ALGORITHM AB We calculate the strong radiative corrections to the process -->W(-->e nu)g*(-->). At the Fermilab Tevatron, this process is the largest background to the associated Higgs boson production pp -->W(-->e nu)H(-->). The calculation is based on the subtraction procedure, and the corrections are found to be significant. [S0556-2821(99)50113-6]. C1 Fermi Natl Accelerator Lab, Theory Grp, Batavia, IL 60510 USA. RP Ellis, RK (reprint author), Fermi Natl Accelerator Lab, Theory Grp, POB 500, Batavia, IL 60510 USA. NR 24 TC 46 Z9 46 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 011501 DI 10.1103/PhysRevD.60.011501 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000002 ER PT J AU Gelb, JM Rosen, SP AF Gelb, JM Rosen, SP TI Another look at "just-so" solar neutrino oscillations SO PHYSICAL REVIEW D LA English DT Article ID VACUUM OSCILLATION; SPECTRUM AB We take another look at "just-so" solar neutrino oscillations, characterizing them by the energy E-pi/2 at which the distance-varying angle is pi/2, instead of by the usual Delta m(2). The rising spectrum recently observed by the SuperKamiokande Collaboration is consistent with an E-pi/2 similar to 6-9 MeV and marginally with 48 MeV. The pp neutrinos must then be reduced to one-half the standard solar model prediction, and Be-7 neutrinos must make up a significant part of the SAGE and GALLEX gallium signal. For E-pi/2 close to 9 and 48 MeV, the Be-7 neutrinos will also show a large seasonal variation, emphasizing the importance of direct measurements of the Be-7 neutrinos. [S0556-2821(99)50213-0]. C1 Univ Texas, Dept Phys, Arlington, TX 76019 USA. US DOE, Germantown, MD 20874 USA. RP Univ Texas, Dept Phys, POB 19059, Arlington, TX 76019 USA. EM gelb@alum.mit.edu; Peter.Rosen@oer.doe.gov NR 31 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1999 VL 60 IS 1 AR 011301 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 214LT UT WOS:000081330000001 ER PT J AU Troha, AL Van Meter, JR Landahl, EC Alvis, RM Unterberg, ZA Li, K Luhmann, NC Kerman, AK Hartemann, FV AF Troha, AL Van Meter, JR Landahl, EC Alvis, RM Unterberg, ZA Li, K Luhmann, NC Kerman, AK Hartemann, FV TI Vacuum electron acceleration by coherent dipole radiation SO PHYSICAL REVIEW E LA English DT Article ID HIGH-INTENSITY LASER; RELATIVISTIC ENERGIES; COMPTON-SCATTERING; FOCUS AB The validity of the concept of laser-driven vacuum acceleration has been questioned, based on an extrapolation of the well-known Lawson-Woodward theorem, which stipulates that plane electromagnetic waves cannot accelerate charged particles in vacuum. To formally demonstrate that electrons can indeed be accelerated in vacuum by focusing or diffracting electromagnetic waves, the interaction between a point charge and coherent dipole radiation is studied in detail. The corresponding four-potential exactly satisfies both Maxwell's equations and the Lorentz gauge condition everywhere, and is analytically tractable. It is found that in the far-field region, where the field distribution closely approximates that of a plane wave, we recover the Lawson-Woodward result, while net acceleration is obtained in the near-field region. The scaling of the energy gain with wave-front curvature and wave amplitude is studied systematically. [S1063-651X(99)00507-3]. C1 Univ Calif Lawrence Livermore Natl Lab, Inst Laser Sci & Appl, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37916 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Theoret Phys, Cambridge, MA 02139 USA. RP Troha, AL (reprint author), Univ Calif Lawrence Livermore Natl Lab, Inst Laser Sci & Appl, Livermore, CA 94550 USA. RI van meter, james/E-7893-2011 NR 19 TC 28 Z9 28 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUL PY 1999 VL 60 IS 1 BP 926 EP 934 DI 10.1103/PhysRevE.60.926 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 218KC UT WOS:000081550900116 PM 11969838 ER PT J AU Spieles, C Vogt, R Gerland, L Bass, SA Bleicher, M Frankfurt, L Strikman, M Stocker, H Greiner, W AF Spieles, C Vogt, R Gerland, L Bass, SA Bleicher, M Frankfurt, L Strikman, M Stocker, H Greiner, W TI Dissociation of expanding cc states in heavy ion collisions SO PHYSICS LETTERS B LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; PB-PB INTERACTIONS; J/PSI SUPPRESSION; CHARMONIUM SUPPRESSION; COLOR TRANSPARENCY; CROSS-SECTIONS; PROTON-NUCLEUS; SPS ENERGIES; 158 GEV/C AB We study J/psi suppression in AB collisions assuming that the charmonium states evolve from small, color transparent configurations. Their interaction with nucleons and nonequilibrated, secondary hadrons is simulated using the microscopic model UrQMD. The Drell-Yan lepton pair yield and the J/psi/Drell-Yan ratio are calculated as a function of the neutral transverse energy in Pb + Pb collisions at 160 GeV and found to be in reasonable agreement with existing data. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, Germany. Duke Univ, Dept Phys, Durham, NC 27708 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. RP Spieles, C (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Bleicher, Marcus/A-2758-2010; Stoecker, Horst/D-6173-2013; OI Stoecker, Horst/0000-0002-3282-3664; Bass, Steffen/0000-0002-9451-0954 NR 37 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUL 1 PY 1999 VL 458 IS 1 BP 137 EP 142 DI 10.1016/S0370-2693(99)00579-1 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 213YX UT WOS:000081301800018 ER PT J AU Atanasiu, CV Boozer, AH Zakharov, LE Subbotin, AA Miron, GI AF Atanasiu, CV Boozer, AH Zakharov, LE Subbotin, AA Miron, GI TI Determination of the vacuum field resulting from the perturbation of a toroidally symmetric plasma SO PHYSICS OF PLASMAS LA English DT Article ID STABILIZATION; COMPUTATION; EQUATIONS; ERATO AB By using the concept of a surface current, the description and calculation of the stability of modes and the plasma response function are greatly simplified. A robustly accurate and effective method is presented to determine these surface currents, considering that the perturbation is given by toroidally coupled tearing modes. A new form of the normal component of the magnetic field perturbation ((B) over tilde(n)), excited by a tearing mode with toroidal coupling, has been derived in terms of the solution of a hypergeometric differential equation, which is also appropriate in the large toroidal mode number (N) limit. Examples of calculations are given for different plasma cross-sectional shapes, including separatrix configurations. (C) 1999 American Institute of Physics. [S1070-664X(99)02107-2]. C1 EURATOM Assoc, Max Planck Inst Plasmaphys, D-85748 Garching, Germany. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. IV Kurchatov Atom Energy Inst, Russian Res Ctr, Moscow 123182, Russia. Inst Atom Phys, R-76900 Bucharest, Romania. RP Atanasiu, CV (reprint author), Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. NR 20 TC 8 Z9 8 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUL PY 1999 VL 6 IS 7 BP 2781 EP 2790 DI 10.1063/1.873235 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 208LV UT WOS:000080993600016 ER PT J AU Gorelenkov, NN Cheng, CZ Fu, GY AF Gorelenkov, NN Cheng, CZ Fu, GY TI Fast particle finite orbit width and Larmor radius effects on low-n toroidicity induced Alfven eigenmode excitation SO PHYSICS OF PLASMAS LA English DT Article ID TOKAMAKS; TFTR AB The effects of finite drift orbit width (FOW) and Larmor radius (FLR) of fast particles on the stability of low-n toroidicity-induced Alfven eigenmodes (TAE) are studied. The formulation is based on the solution of the low frequency gyrokinetic equation (omega much less than omega(c), where omega(c) is particle cyclotron frequency). A quadratic form has been derived in terms of invariant variables; energy epsilon, magnetic moment mu, and toroidal angular momentum P-phi;. The growth rate of the TAE is computed perturbatively using numerical averaging over the fast particle drift orbit. This new computational capability improves the NOVA-K code [G. Y. Fu, C. Z. Cheng, and K. L. Wong, Phys. Fluids B 5, 4040 (1994)] which included FOW effects in the growth rate calculation based on small radial orbit width approximation. The new NOVA-K version has been benchmarked for different regimes of particle TAE excitation. It is shown that both FOW and FLR effects are typically stabilizing; the TAE growth rate can be reduced by as much as a factor of 2 for tokamak fusion test reactor supershots [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. However, FOW may be destabilizing for the global modes, which are localized at the plasma edge. (C) 1999 American Institute of Physics. [S1070-664X(99)03107-9]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. TRINITI, Troitsk 142092, Moscow Region, Russia. RP Gorelenkov, NN (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Cheng, Chio/K-1005-2014 NR 16 TC 56 Z9 56 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUL PY 1999 VL 6 IS 7 BP 2802 EP 2807 DI 10.1063/1.873545 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 208LV UT WOS:000080993600019 ER PT J AU Redi, MH Batha, SH Budny, RV Darrow, DS Levinton, FM McCune, DC Medley, SS Petrov, MP von Goeler, S White, RB Zarnstorff, MC Zweben, SJ AF Redi, MH Batha, SH Budny, RV Darrow, DS Levinton, FM McCune, DC Medley, SS Petrov, MP von Goeler, S White, RB Zarnstorff, MC Zweben, SJ CA TFTR Team TI Neoclassical simulations of fusion alpha particles in pellet charge exchange experiments on the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID N MAGNETIC PERTURBATIONS; RIPPLE LOSS; TFTR; IONS; TRANSPORT; PLASMAS AB Neoclassical simulations of alpha particle density profiles in high fusion power plasmas on the Tokamak Fusion Test Reactor [Phys. Plasmas 5, 1577 (1998)] are found to be in good agreement with measurements of the alpha distribution function made with a sensitive active neutral particle diagnostic. The calculations are carried out in Hamiltonian magnetic coordinates with a fast, particle-following Monte Carlo code which includes the neoclassical transport processes, a recent first-principles model for stochastic ripple loss and collisional effects. New calculations show that monotonic shear alpha particles are virtually unaffected by toroidal field ripple. The calculations show that in reversed shear the confinement domain is not empty for trapped alphas at birth and allow an estimate of the actual alpha particle densities measured with the pellet charge exchange diagnostic. (C) 1999 American Institute of Physics. [S1070-664X(99)03807-0]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Redi, MH (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 24 TC 5 Z9 5 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUL PY 1999 VL 6 IS 7 BP 2826 EP 2833 DI 10.1063/1.873717 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 208LV UT WOS:000080993600022 ER PT J AU Cooper, F AF Cooper, F TI Inclusive dilepton production at RHIC: a field theory approach based on a non-equilibrium chiral phase transition SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NM DE dilepton production; non-equilibrium processes; closed time path (CTP) formalism ID EVOLUTION; PHOTON; MODEL AB Recently a real time picture of quantum field theory has been developed which allows one to look into the time evolution of a scattering process. We discuss two pictures for discussing non-equilibrium processes, namely the Schrodinger picture and the Heisenberg picture and show that a time-dependent variational method is equivalent to the leading order in large-N approximation in the Heisenberg picture. We then discuss the dynamics of a non-equilibrium chiral phase transition in mean field theory in the O(4) sigma model. We show how the pion spectrum can be enhanced at low momentum because of non-equilibrium effects. We then show how to use Schwinger's CTP formalism to calculate the inclusive dilepton spectrum coming from the pion plasma. We find that a noticeable enhancement occurs in this spectrum, but that there are large numerical uncertainties due to errors connected with the finite times used to do our numerical simulations. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Cooper, F (reprint author), Los Alamos Natl Lab, Div Theoret, MS B285, Los Alamos, NM 87545 USA. EM fcooper@lanl.gov NR 14 TC 4 Z9 4 U1 0 U2 0 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 JUL PY 1999 VL 315 IS 1-3 BP 59 EP 81 DI 10.1016/S0370-1573(99)00013-7 PG 23 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500005 ER PT J AU Chapline, G AF Chapline, G TI Is theoretical physics the same thing as mathematics? SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NEW MEXICO ID MOYAL QUANTIZATION; SYSTEMS AB The growing realization that the fundamental mathematical structure underlying superstring models is closely related to Langlands' program for the unification of mathematics suggests that the relationship between theoretical physics and mathematics is more intimate than previously thought. We show that quantum mechanics can be interpreted as a canonical method for solving pattern recognition problems, which suggests that mathematics is really just a reflection of the fundamental laws of physics. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Chapline, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 32 TC 11 Z9 11 U1 0 U2 3 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 JUL PY 1999 VL 315 IS 1-3 BP 95 EP 105 DI 10.1016/S0370-1573(99)00015-0 PG 11 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500007 ER PT J AU Timmermans, E Tommasini, P Hussein, MS Kerman, A AF Timmermans, E Tommasini, P Hussein, MS Kerman, A TI Feshbach resonances in atomic Bose-Einstein condensates SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NM DE Bose-Einstein condensates; Feshbach resonance; coherent matter wave dynamics ID ATTRACTIVE INTERACTIONS; COLLISIONS; GAS; SCATTERING; FIELDS AB The low-energy Feshbach resonances recently observed in the inter-particle interactions of trapped ultra-cold atoms involve an intermediate quasi-bound molecule with a spin arrangement that differs from the trapped atom spins. Variations of the strength of an external magnetic field then alter the difference of the initial and intermediate state energies (i.e. the 'detuning'). The effective scattering length that describes the low-energy binary collisions, similarly varies with the near-resonant magnetic field. Since the properties of the dilute atomic Bose-Einstein condensates (BECs) are extremely sensitive to the value of the scattering length, a 'tunable' scattering length suggests highly interesting many-body studies. In this paper, we review the theory of the binary collision Feshbach resonances, and we discuss their effects on the many-body physics of the condensate. We point out that the Feshbach resonance physics in a condensate can be considerably richer than that of an altered scattering length: the Feshbach resonant atom-molecule coupling can create a second condensate component of molecules that coexists with the atomic condensate. Far off-resonance, a stationary condensate does behave as a single condensate with effective binary collision scattering length. However, even in the off-resonant limit, the dynamical response of the condensate mixture to a sudden change in the external magnetic field carries the signature of the molecular condensate's presence: experimentally observable oscillations of the number of atoms and molecules. We also discuss the stationary states of the near-resonant condensate system. We point out that the physics of a condensate that is adiabatically tuned through resonance depends on its history, i.e. whether the condensate starts out above or below resonance. Furthermore, we show that the density dependence of the many-body ground-state energy suggests the possibility of creating a dilute condensate system with the liquid-like property of a self-determined density. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Harvard Smithsonian Ctr Astrophys, Inst Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Los Alamos Natl Lab, T-4, Los Alamos, NM 87545 USA. EM eddy@t4.lanl.gov NR 46 TC 450 Z9 453 U1 2 U2 30 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD JUL PY 1999 VL 315 IS 1-3 BP 199 EP 230 DI 10.1016/S0370-1573(99)00025-3 PG 32 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500013 ER PT J AU Ginocchio, JN AF Ginocchio, JN TI A relativistic symmetry in nuclei SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NEW MEXICO ID PSEUDOSPIN SYMMETRY; STATES; MODEL AB We review the status of a quasi-degenerate doublets in nuclei, called pseudospin doublers, which were discovered about 30 years ago and the origins of which have remained a mystery, until recently. We show that pseudospin doublets originate from an SU(2) symmetry of the Dirac Hamiltonian which occurs when the scalar and vector potentials are opposite in sign but equal in magnitude. Furthermore, we survey the evidence that pseudospin symmetry is approximately conserved for a Dirac Hamiltonian with realistic scalar and vector potentials. We briefly discuss the relationship of pseudospin symmetry with chiral symmetry and the implications of pseudospin symmetry for the antinucleon spectrum in nuclei. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ginocchio, JN (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 25 TC 145 Z9 149 U1 0 U2 2 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 JUL PY 1999 VL 315 IS 1-3 BP 231 EP 240 DI 10.1016/S0370-1573(99)00021-6 PG 10 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500014 ER PT J AU Hayes, AC AF Hayes, AC TI Nuclear structure issues determining neutrino-nucleus cross sections SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NEW MEXICO DE neutrino interactions; nuclear structure; shell model ID SCATTERING; C-12 AB We investigate the nuclear structure issues that determine the neutrino-nucleus cross sections of interest in nuclear, particle, and astrophysics. We discuss the uncertainties involved in calculating these cross sections, and the expected accuracy of model predictions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Hayes, AC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 16 TC 14 Z9 14 U1 0 U2 3 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 JUL PY 1999 VL 315 IS 1-3 BP 257 EP 271 DI 10.1016/S0370-1573(99)00026-5 PG 15 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500016 ER PT J AU Mandula, JE AF Mandula, JE TI The gluon propagator SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Article; Proceedings Paper CT Symposium in Honor of Richard Slansky on Looking Forward - Frontiers in Theoretical Science CY MAY 20-21, 1998 CL LOS ALAMOS, NM DE gluon; propagator; gauge; lattice ID NON-PERTURBATIVE CALCULATION; FUNDAMENTAL MODULAR REGION; MINIMAL LANDAU GAUGE; GHOST PROPAGATORS; INFRARED LIMIT; GRIBOV COPIES; LATTICE; CONFINEMENT; FIELD; SU(2) AB We discuss the current state of what is known non-perturbatively about the gluon propagator in QCD, with emphasis on the information coming from lattice simulations. We review specification of the lattice Landau gauge and the procedure for calculating the gluon propagator on the lattice. We also discuss some of the difficulties in non-perturbative calculations - especially Gribov copy issues. We trace the evolution of lattice simulations over the past dozen years, emphasizing how the improvement in computations has led not only to more precise determinations of the propagator, but has allowed more detailed information about it to be extracted. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 US DOE, Div High Energy Phys, Washington, DC 20585 USA. RP US DOE, Div High Energy Phys, Washington, DC 20585 USA. EM jeffrey.mandula@science.doe.gov NR 35 TC 50 Z9 50 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD JUL PY 1999 VL 315 IS 1-3 BP 273 EP 284 DI 10.1016/S0370-1573(99)00027-7 PG 12 WC Physics, Multidisciplinary SC Physics GA 214LM UT WOS:000081329500017 ER PT J AU Touryan, KJ AF Touryan, KJ TI More on bottom-up funding of FSU science: Another ongoing program, a plea for reform SO PHYSICS TODAY LA English DT Letter C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Touryan, KJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 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 JUL PY 1999 VL 52 IS 7 BP 15 EP 15 DI 10.1063/1.882742 PG 1 WC Physics, Multidisciplinary SC Physics GA 212VV UT WOS:000081239100002 ER PT J AU Shaw, R AF Shaw, R TI Discharge duty SO PHYSICS WORLD LA English DT Letter C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Shaw, R (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8585 J9 PHYS WORLD JI Phys. World PD JUL PY 1999 VL 12 IS 7 BP 18 EP 18 PG 1 WC Physics, Multidisciplinary SC Physics GA 215MD UT WOS:000081384700020 ER PT J AU Wootton, A AF Wootton, A TI Taking a small-scale approach to fusion SO PHYSICS WORLD LA English DT News Item C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Wootton, A (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8585 J9 PHYS WORLD JI Phys. World PD JUL PY 1999 VL 12 IS 7 BP 46 EP 46 PG 1 WC Physics, Multidisciplinary SC Physics GA 215MD UT WOS:000081384700030 ER PT J AU Stutman, D Finkenthal, M Soukhanovskii, V Menard, J Munsat, T Kaita, R Majeski, R AF Stutman, D Finkenthal, M Soukhanovskii, V Menard, J Munsat, T Kaita, R Majeski, R TI Spectroscopic evidence for high harmonic fast wave heating in the CDX-U spherical torus SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID IMPURITY TRANSPORT; TOKAMAK; PLASMAS AB We present evidence for high harmonic fast wave (HHFW) heating in the core of the CDX-U spherical torus (aspect ratio R/a approximate to 1.5) at the Princeton Plasma Physics Laboratory. We use a spectroscopic technique combining fast, multichordal measurements of the ultrasoft x-ray line emission from intrinsic C and O. The results show that in a few cases substantial (nearly 50%) increases in the core electron temperature can be obtained with only about 100 kW of radio-frequency power, compared to approximate to 150 kW ohmic input. Modifications of the core magnetohydrodynamic activity consistent with the estimated T-e increase are also observed. The majority of the discharges exhibit only modest core T-e increases however, with most of the heating occurring outside r/a approximate to 0.5. A proposed explanation for this effect consistent with the experimental observations is based on a neoclassical transport instability for low-Z impurities, similar to an effect recently described for high-Z impurities in large tokamaks. C1 Johns Hopkins Univ, Baltimore, MD 21218 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Stutman, D (reprint author), Johns Hopkins Univ, Baltimore, MD 21218 USA. RI Stutman, Dan/P-4048-2015; OI Menard, Jonathan/0000-0003-1292-3286 NR 20 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD JUL PY 1999 VL 41 IS 7 BP 867 EP 879 DI 10.1088/0741-3335/41/7/302 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 224AD UT WOS:000081873000003 ER PT J AU Gamwo, IK Soong, Y Lyczkowski, RW AF Gamwo, IK Soong, Y Lyczkowski, RW TI Numerical simulation and experimental validation of solids flows in a bubbling fluidized bed SO POWDER TECHNOLOGY LA English DT Article DE gas-solids flow; experimental validation solids flows; numerical simulation; bubbling fluidized bed hydrodynamics ID HYDRODYNAMICS; PRESSURE AB A transient two-phase simulation reactor model for describing the hydrodynamics in a bubbling-fluidized bed was performed. A summary of the numerical method refined for over a decade is presented. The hydrodynamic model, based on the two-fluid theory, was validated with regards to the solids flow patterns in a fluidized bed operated under isothermal conditions. The predicted trends compared well with the experimental solids velocity field. The simulation appears to mimic experimental results accurately: both the simulation and the experiment show that the solids motion follows a 'gulf-stream' pattern with solids rising upward in the middle of the bed and falling downward near the side walls. The weak vortex patterns observed in the lower portion of the bed have also been simulated. Comparison of predicted and experimental axial solids velocities were in generally good agreement. This good agreement was found to be a function of the solids viscosity and not of the nonuniform inlet gas velocity. (C) 1999 Elsevier Science S.A. C1 US DOE, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. Argonne Natl Lab, Div Energy Syst, Argonne, IL 60439 USA. RP Gamwo, IK (reprint author), Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. NR 29 TC 23 Z9 23 U1 0 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0032-5910 J9 POWDER TECHNOL JI Powder Technol. PD JUL PY 1999 VL 103 IS 2 BP 117 EP 129 DI 10.1016/S0032-5910(98)00218-6 PG 13 WC Engineering, Chemical SC Engineering GA 203YN UT WOS:000080735900006 ER PT J AU Aiken, DJ Barnett, AM AF Aiken, DJ Barnett, AM TI Alternative contact designs for thin epitaxial silicon solar cells SO PROGRESS IN PHOTOVOLTAICS LA English DT Article ID LATERAL OVERGROWTH; FILMS AB Two major opportunities for increasing the performance of crystalline silicon solar cells involve reducing their thickness and reducing the losses associated with their front metallic grid contacts. Front grid contacted thin epitaxial silicon solar cells based on the growth of crystalline silicon films on a substrate or superstrate have been reported for many years, as have wafer-based solar cells with alternative contact approaches, integrating these two concepts into a single device presents an opportunity for simultaneously reducing two major loss mechanisms associated with crystalline silicon solar cells. The opportunities that exist and challenges that must be overcome in order to realize such a device are described in this paper. The design space is defined and explored by considering a wide range of possible approaches. A specific approach was chosen and used to design, grow, and fabricate a proof-of-concept thin epitaxial silicon solar cell with an embedded semiconductor grid as an alternative to a conventional front metallic grid. The work presented here has resulted in a thin epitaxial silicon solar cell with a 7.8% designated area conversion efficiency, well isolated contacts, negligible series resistive power loss, and less than 1% shading of the designated area. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Delaware, Dept Elect & Comp Engn, Newark, DE 19716 USA. RP Aiken, DJ (reprint author), Sandia Natl Labs, POB 5800,MS 0752, Albuquerque, NM 87185 USA. NR 28 TC 1 Z9 1 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1062-7995 J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD JUL-AUG PY 1999 VL 7 IS 4 BP 275 EP 285 DI 10.1002/(SICI)1099-159X(199907/08)7:4<275::AID-PIP258>3.0.CO;2-S PG 11 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 235CF UT WOS:000082521200003 ER PT J AU Osterwald, CR Anevsky, S Bucher, K Barua, AK Chaudhuri, P Dubard, J Emery, K Hansen, B King, D Metzdorf, J Nagamine, F Shimokawa, R Wang, YX Wittchen, T Zaaiman, W Zastrow, A Zhang, J AF Osterwald, CR Anevsky, S Bucher, K Barua, AK Chaudhuri, P Dubard, J Emery, K Hansen, B King, D Metzdorf, J Nagamine, F Shimokawa, R Wang, YX Wittchen, T Zaaiman, W Zastrow, A Zhang, J TI The World Photovoltaic Scale: An international reference cell calibration program SO PROGRESS IN PHOTOVOLTAICS LA English DT Article AB This paper describes the World Photovoltaic Scale (WPVS) international reference cell calibration program. The WPVS provides a scale for PV performance measurements that has been established through round-robin calibration of a group of primary monocrystalline Si reference cells and is traceable to Systeme International (SI) units. Procedures for recalibration of the reference cell group have been devised, along with procedures for admittance and calibration of new reference cells. A reference cell package has been designed that meets the unique needs of the WP VS. It is hoped that the existing WPVS group will eventually be replaced with cells of the new design that have passed a comprehensive acceptance-test procedure. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. All Union Res Inst Optophys Measurements, Moscow, Russia. Fraunhofer Inst Solar Energy Syst, D-7800 Freiburg, Germany. Indian Assoc Cultivat Sci, Kolkata 700032, W Bengal, India. Lab Cent Ind Elect, Fontenay Aux Roses, France. Sandia Natl Labs, Albuquerque, NM 87185 USA. Phys Tech Bundesanstalt, D-3300 Braunschweig, Germany. Japan Qual Assurance Org, Tokyo, Japan. Electrotech Lab, Tsukuba, Ibaraki, Japan. Tianjin Inst Power Sources, Tianjin, Peoples R China. European Solar Test Installat, Ispra, Italy. Natl Inst Metrol, Beijing, Peoples R China. RP Osterwald, CR (reprint author), Natl Renewable Energy Lab, MS 3411,,1617 Cole Blvd, Golden, CO 80401 USA. EM carl_osterwald@nrel.gov NR 8 TC 33 Z9 35 U1 0 U2 12 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1062-7995 EI 1099-159X J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD JUL-AUG PY 1999 VL 7 IS 4 BP 287 EP 297 PG 11 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 235CF UT WOS:000082521200004 ER PT J AU Contreras, MA Egaas, B Ramanathan, K Hiltner, J Swartzlander, A Hasoon, F Noufi, R AF Contreras, MA Egaas, B Ramanathan, K Hiltner, J Swartzlander, A Hasoon, F Noufi, R TI Progress toward 20% efficiency in Cu(In,Ca)Se(2) polycrystalline thin-film solar cells SO PROGRESS IN PHOTOVOLTAICS LA English DT Article ID CHALCOPYRITE AB This short communication reports on achieving 18.8% total-area conversion efficiency for a ZnO/CdS/Cu(In,Ga)Se(2)/Mo polycrystalline thin-film solar cell. We also report a 15%-efficient, Cd-free device fabricated via physical vapor deposition methods. The Cd-free cell includes no buffer layer, and it is fabricated by direct deposition of ZnO on the Cu(ln,Ga)Se(2) thin-film absorber. Both results have been measured at the National Renewable Energy Laboratory under standard reporting conditions (1000 W/m(2), 25 degrees C, ASTM E 892 Global). The 18.8% conversion efficiency represents a new record for such devices (Notable Exceptions) and makes the 20% performance level by thin-film polycrystalline materials much closer to reality. We allude to rite enhancement in performance of such cells as compared to previous record cells, and we discuss possible and realistic routes to enhance the performance reward the 20% efficiency level. Published in 1999 by John Wiley & Sons, Ltd. This article is a US government work and is in the public domain in the United States. C1 NREL, Golden, CO 80401 USA. Colorado State Univ, Dept Phys, PV Lab, Ft Collins, CO 80523 USA. RP Contreras, MA (reprint author), NREL, MS 3211,1617 Cole Blvd, Golden, CO 80401 USA. EM miguel_contreras@nrel.gov NR 15 TC 918 Z9 933 U1 13 U2 165 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1062-7995 J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD JUL-AUG PY 1999 VL 7 IS 4 BP 311 EP 316 PG 6 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 235CF UT WOS:000082521200006 ER PT J AU Green, MA Emery, K Bucher, K King, DL Igari, S AF Green, MA Emery, K Bucher, K King, DL Igari, S TI Solar cell efficiency tables (version 14) SO PROGRESS IN PHOTOVOLTAICS LA English DT Article ID MULTICRYSTALLINE AB Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since January 1999 ape briefly described. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ New S Wales, Photovolt Special Res Ctr, Sydney, NSW 2052, Australia. Natl Renewable Energy Lab, Golden, CO 80401 USA. Fraunhofer Inst Solar Energy Syst, D-79100 Freiburg, Germany. Sandia Natl Labs, Div 6224, Albuquerque, NM 87185 USA. Japan Qual Assurance Org, Solar Techno Ctr, Solar Cell Test Res Div, Hamamatsu, Shizuoka 43112, Japan. RP Green, MA (reprint author), Univ New S Wales, Photovolt Special Res Ctr, Sydney, NSW 2052, Australia. EM m.green@unsw.edu.au NR 49 TC 21 Z9 21 U1 1 U2 11 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1062-7995 J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD JUL-AUG PY 1999 VL 7 IS 4 BP 321 EP 326 DI 10.1002/(SICI)1099-159X(199907/08)7:4<321::AID-PIP283>3.0.CO;2-H PG 6 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 235CF UT WOS:000082521200008 ER PT J AU Hirata, Y Nara, Y Ohnishi, A Harada, T Randrup, J AF Hirata, Y Nara, Y Ohnishi, A Harada, T Randrup, J TI Quantum fluctuation effects on hyperfragment formation from Xi(-) absorption at rest on C-12 SO PROGRESS OF THEORETICAL PHYSICS LA English DT Article ID ANTISYMMETRIZED MOLECULAR-DYNAMICS; HEAVY-ION REACTIONS; WAVE-PACKET DYNAMICS; STATISTICAL PROPERTIES; 2-NUCLEON COLLISIONS; FRAGMENT FORMATION; NUCLEON-EMISSION; HYPERNUCLEI; DEPENDENCE; VERSION AB Formation mechanisms of single, twin and double hypernuclei from Xi absorption at rest on C-12 are investigated with a refined microscopic transport model that incorporates the recently developed quantal Langevin treatment into antisymmetrized molecular dynamics. With a choice of the fluctuation strength that describes dynamical fragmentation processes in the p + C-12 reaction at 45 MeV quite well, the quantum fluctuations suppress the formation probability of double hyperfragments to around 10%, which is comparable to the experimental data, and the dynamical formation of twin hyperfragment can be described qualitatively. C1 Hokkaido Univ, Grad Sch Sci, Div Phys, Sapporo, Hokkaido 0600810, Japan. Japan Atom Energy Res Inst, Adv Sci Res Ctr, Tokai, Ibaraki 3191195, Japan. Sapporo Gakuin Univ, Dept Social Informat, Ebetsu, Hokkaido 0698555, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Hirata, Y (reprint author), Hokkaido Univ, Grad Sch Sci, Div Phys, Sapporo, Hokkaido 0600810, Japan. EM hirata@nucl.sci.hokudai.ac.jp RI Ohnishi, Akira/F-7403-2011 OI Ohnishi, Akira/0000-0003-1513-0468 NR 52 TC 14 Z9 14 U1 0 U2 0 PU PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE PI KYOTO PA C/O KYOTO UNIV, YUKAWA HALL, KYOTO, 606-8502, JAPAN SN 0033-068X J9 PROG THEOR PHYS JI Prog. Theor. Phys. PD JUL PY 1999 VL 102 IS 1 BP 89 EP 119 DI 10.1143/PTP.102.89 PG 31 WC Physics, Multidisciplinary SC Physics GA 223PC UT WOS:000081848600006 ER PT J AU Thornton, K Forstner, M Shen, MR West, MG Rupp, B Thelen, MP AF Thornton, K Forstner, M Shen, MR West, MG Rupp, B Thelen, MP TI Purification, characterization, and crystallization of the distal BRCT domain of the human XRCC1 DNA repair protein SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article DE BRCT domain; XRCC1; DNA ligase III; single-strand break repair; protein-protein interaction; crystallography ID LIGASE-III; DAMAGE; POLYMERASE; INTERACTS; MUTATIONS AB The XRCC1 DNA repair protein contains two regions of approximately 100 amino acids each that share homology with the BRCT (BRCA1 carboxyl terminus) domain superfamily. These two regions of XRCC1 have been shown to interact independently with DNA ligase III and poly(ADP-ribose)polymerase as part of a mechanism involved in the repair of DNA single-strand breaks. To understand how these BRCT regions specify protein-protein interactions and contribute to DNA repair function, we have overexpressed and purified the distal BRCT domain of XRCC1 with the goal of structure determination. The cDNA encoding this BRCT region (X1BRCTb) was inserted into the pET29 bacterial expression vector; the polypeptide was expressed in mostly soluble form and then purified by anion-exchange and gel filtration chromatography. Crystallization screening with the purified material resulted in the formation of large bipyramidal crystals. Crystals formed within several hours at room temperature from salt solutions of ammonium sulfate. Crystals diffract to similar to 2.85 Angstrom and were found to be in space group P4(1)2(1)2 (or its enantiomorph P4(3)2(1)2) with unit cell dimensions a = 100.43 Angstrom, c = 105.62 Angstrom. Crystals of similar character have also been obtained after incorporation of selenomethionine during expression of the protein. Efforts are now under way to determine the molecular structure of-the X1BRCTb domain. These studies are likely to give insight into the interaction between XRCC1 and DNA Ligase III and into general structural features of BRCT domains that exist in many other proteins. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mol & Struct Biol Div, Livermore, CA 94550 USA. RP Thelen, MP (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. RI Thelen, Michael/C-6834-2008; Thelen, Michael/G-2032-2014 OI Thelen, Michael/0000-0002-2479-5480; Thelen, Michael/0000-0002-2479-5480 FU NCI NIH HHS [CA76116] NR 21 TC 6 Z9 8 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-5928 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD JUL PY 1999 VL 16 IS 2 BP 236 EP 242 DI 10.1006/prep.1999.1070 PG 7 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 216BU UT WOS:000081421300005 PM 10419820 ER PT J AU Prive, GG Anderson, DH Wesson, L Cascio, D Eisenberg, D AF Prive, GG Anderson, DH Wesson, L Cascio, D Eisenberg, D TI Packed protein bilayers in the 0.90 angstrom resolution structure of a designed alpha helical bundle SO PROTEIN SCIENCE LA English DT Article DE atomic resolution; biomaterial; crystal engineering; peptide design; peptide physics ID CRYSTAL-STRUCTURE DETERMINATION; EUPLOTES-RAIKOVI; PHEROMONE ER-1; PEPTIDE; REFINEMENT AB A 12-residue peptide designed to form an ct-helix and self-associate into an antiparallel 4-alpha-helical bundle yields a 0.9 Angstrom crystal structure revealing unanticipated features. The structure was determined by direct phasing with the "Shake-and-Bake" program, and contains four crystallographically distinct 12-mer peptide molecules plus solvent for a total of 479 atoms. The crystal is formed from nearly ideal alpha-helices hydrogen bonded head-to-tail into columns, which in turn pack side-by-side into sheets spanning the width of the crystal. Within each sheet, the cr-helices run antiparallel and are closely spaced (9-10 Angstrom center-to-center). The sheets are more loosely packed against each other (13-14 Angstrom between helix centers). Each sheet is amphiphilic: apolar leucine side chains project from one face, charged lysine and glutamate side chains from the other face. The sheets are stacked with two polar faces opposing and two apolar faces opposing. The result is a periodic biomaterial composed of packed protein bilayers, with alternating polar and apolar interfaces. All of the 30 water molecules in the unit cell lie in the polar interface or between the stacked termini of helices. A section through the sheet reveals that the helices packed at the apolar interface resemble the four-ct-helical bundle of the design, but the helices overhang parts of the adjacent bundles, and the helix crossing angles are less steep than intended (7-11 degrees rather than 18 degrees). C1 Univ Calif Los Angeles, DOE, Inst Mol Biol, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Toronto, Ontario Canc Inst, Toronto, ON M5G 2M9, Canada. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, DOE, Inst Mol Biol, Lab Struct Biol & Mol Med, Box 951570, Los Angeles, CA 90095 USA. NR 29 TC 26 Z9 26 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD JUL PY 1999 VL 8 IS 7 BP 1400 EP 1409 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 213KL UT WOS:000081271700003 PM 10422828 ER PT J AU Patterson, WR Anderson, DH DeGrado, WF Cascio, D Eisenberg, D AF Patterson, WR Anderson, DH DeGrado, WF Cascio, D Eisenberg, D TI Centrosymmetric bilayers in the 0.75 angstrom resolution structure of a designed alpha-helical peptide, D,L-Alpha-1 SO PROTEIN SCIENCE LA English DT Article DE amphiphilic bilayer; atomic resolution; centrosymmetric; designed peptide; rigid body analysis ID CRYSTAL-STRUCTURE DETERMINATION; ATOMIC DISPLACEMENT PARAMETERS; MATING PHEROMONE ER-1; EUPLOTES-RAIKOVI; PROTEIN CRYSTALS; DIFFRACTION; MOTIONS AB We report the 0.75 Angstrom crystal structure of a racemic mixture of the 12-residue designed peptide "Alpha-1" (Acetyl-ELLKKLLEELKG), the L-enantiomer of which is described in the accompanying paper. Equivalent solutions of the centrosymmetric bilayers were determined by two direct phasing programs in space groups pi and P (1) over bar. The unit cell contains two L-alpha-helices and two D-alpha-helices. The columnar-sheet bilayer motif seen in L-Alpha-l is maintained in the D,L-Alpha-l structure except that each sheet of head-to-tail helices is composed of one enantiomer and is related to its neighboring sheets by inversion symmetry. Comparison to the L-Alpha-l structure provides further insight into peptide design. The high resolution and small asymmetric unit allowed building an intricate model (R = 13.1%, R-free = 14.5%) that incorporates much of the discrete disorder of peptide and solvent. Ethanolamine and 2-methyl-2,4-pentanediol (MPD) molecules bind near helix termini. Rigid body analysis identifies sites of restricted displacements and torsions. Side-chain discrete disorder propagates into the backbone of one helix but not the other. Although no side chain in Alpha-1 is rigid, the environments in the crystal restrict some of them to no or only one active torsion. C1 Univ Calif Los Angeles, Inst Mol Biol, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Penn, Sch Med, Dept Biochem & Biophys, Philadelphia, PA 19104 USA. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, Inst Mol Biol, DOE, Lab Struct Biol & Mol Med, Box 951570, Los Angeles, CA 90095 USA. NR 39 TC 31 Z9 31 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD JUL PY 1999 VL 8 IS 7 BP 1410 EP 1422 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 213KL UT WOS:000081271700004 PM 10422829 ER PT J AU Boatright, D Brandt, M Phillips, M AF Boatright, D Brandt, M Phillips, M TI The schools of public health and practice an environmental health partnership: Bringing students to the science SO PUBLIC HEALTH REPORTS LA English DT Article C1 Univ Oklahoma, Hlth Sci Ctr, Coll Publ Hlth, Dept Environm & Occupat Hlth, Norman, OK 73019 USA. Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Ind Hyg & Safety Grp, Los Alamos, NM 87545 USA. RP Boatright, D (reprint author), Univ Oklahoma, Hlth Sci Ctr, Coll Publ Hlth, Dept Environm & Occupat Hlth, Norman, OK 73019 USA. NR 8 TC 1 Z9 1 U1 0 U2 3 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 0033-3549 J9 PUBLIC HEALTH REP JI Public Health Rep. PD JUL-AUG PY 1999 VL 114 IS 4 BP 384 EP 387 DI 10.1093/phr/114.4.384 PG 4 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 224ZE UT WOS:000081929200026 PM 10501143 ER PT J AU Kaye, AB Handler, G Krisciunas, K Poretti, E Zerbi, FM AF Kaye, AB Handler, G Krisciunas, K Poretti, E Zerbi, FM TI gamma Doradus stars: Defining a new class of pulsating variables SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID LINE-PROFILE VARIATIONS; F-TYPE STARS; DELTA-SCUTI; NONRADIAL PULSATIONS; 9-AURIGAE; VARIABILITY; HD-164615; CAMPAIGN; UVBY AB In this paper we describe a new class of pulsating stars, the prototype of which is the bright, early, F-type dwarf gamma Doradus. These stars typically have between 1 and 5 periods ranging from 0.4 to 3 days with photometric amplitudes up to 0.1 mag in Johnson V. The mechanism for these observed variations is high-order, low-degree, nonradial, gravity-mode pulsation. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Univ Vienna, Astron Inst, A-1010 Vienna, Austria. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Osservatorio Astron Brera Merate, Milan, Italy. RP Kaye, AB (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. OI Zerbi, Filippo Maria/0000-0002-9996-973X NR 38 TC 128 Z9 128 U1 0 U2 0 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 JUL PY 1999 VL 111 IS 761 BP 840 EP 844 DI 10.1086/316399 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 219MW UT WOS:000081611900008 ER PT J AU Marshak, A Wiscombe, W Davis, A Oreopoulos, L Cahalan, R AF Marshak, A Wiscombe, W Davis, A Oreopoulos, L Cahalan, R TI On the removal of the effect of horizontal fluxes in two-aircraft measurements of cloud absorption SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE aircraft observations; short-wave radiation ID INDEPENDENT PIXEL APPROXIMATION; STRATOCUMULUS CLOUDS; SOLAR ABSORPTION; RADIATION AB Cloud absorption inferred from the difference between the net fluxes measured by stacked aircraft below and above clouds is strongly affected by the uncertainties due to cloud horizontal inhomogeneity. The simplest way to get rid of these uncertainties is to perform grand averages over flight legs; if flight legs are long enough, grand averaging may lead to a reliable estimate of cloud absorption. However, the amount of information on 'true' cloud absorption returned from such an expensive measurement program will be very limited-often one number per flight leg. This paper contains a discussion on how to enhance the harvest of true absorption data using two related methods: (a) subtraction and (b) conditional sampling. Both methods assume that, simultaneously with broadband measurements, some narrow non-absorbing-band net flux measurements are also available. Both methods are related to Ackerman-Cox type corrections, where subtracting fluxes in a transparent spectral band from those in an absorbing band partially removes the radiative effects of horizontal inhomogeneity and allows the recovery of spatially resolved cloud absorption. The output of the two methods is different: while the subtraction method provides a contiguous record of recovered cloud absorption, the conditional sampling method yields a discrete set of data points where the vertical net flux divergence reliably estimates true cloud absorption. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Marshak, A (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, 1000 Hilltop Circle, Baltimore, MD 21250 USA. RI Oreopoulos, Lazaros/E-5868-2012; Cahalan, Robert/E-3462-2012; Wiscombe, Warren/D-4665-2012; Marshak, Alexander/D-5671-2012 OI Oreopoulos, Lazaros/0000-0001-6061-6905; Cahalan, Robert/0000-0001-9724-1270; Wiscombe, Warren/0000-0001-6844-9849; NR 26 TC 14 Z9 14 U1 0 U2 0 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JUL PY 1999 VL 125 IS 558 BP 2153 EP 2170 DI 10.1002/qj.49712555811 PN B PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230MK UT WOS:000082254800010 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 International radiobiology archives of long-term animal studies: structure, possible uses and potential extension SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Review AB Animal experiments have contributed a great deal to our information on effects and risks arising from exposure to radionuclides. This applies, in particular, to alpha-emitting radionuclides where information from man is limited to thorotrast, Ra-224 and Ra-226. The late C.W. Mays was the first to suggest that animal data in conjunction with epidemiological data could allow estimates of human risks for radionuclides - predominantly from actinides - where information in man is scarce. The 'International Radiobiology Archives of Long-term Animal Studies' were created through the combined efforts of European, American and Japanese scientists and aim to safeguard the large amount of existing data on longterm animal experiments and make them available for, among others, an improved assessment of risks from alpha-emitting radionuclides. This paper summarizes the structure of the archives and reviews their present status and future plans. It also demonstrates the extensive information available in these archives on alpha-emitting radionuclides which is suitable for further analysis. Also, the structure of the animal archives could - in a slightly modified form - accommodate the epidemiological data available on Ra-224 and thorotrast and, thus, facilitate a. direct comparison of data from man, dogs and rodents. C1 European Late Effect Project Grp, B-2400 Mol, Belgium. GSF, Inst Radiobiol, Neuherberg, Germany. Pacific NW Lab, Richland, WA 99352 USA. GSF, Inst Pathol, Neuherberg, Germany. RP Gerber, GB (reprint author), European Late Effect Project Grp, De Heylanden 7, B-2400 Mol, Belgium. NR 7 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD JUL PY 1999 VL 38 IS 2 BP 75 EP 79 DI 10.1007/s004110050141 PG 5 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA 223ND UT WOS:000081846400001 PM 10461752 ER PT J AU Dingfelder, M Inokuti, M AF Dingfelder, M Inokuti, M TI The Bethe surface of liquid water SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article ID RAY-SCATTERING SPECTROSCOPY AB The Bethe surface of liquid water, which was previously calculated by using a semiempirical model, is compared with recently available data from IXS experiments (inelastic x-ray scattering; Compton scattering of high energy photons) in liquid water. No alarming discrepancy is found for a global view of the Bethe surface, in part because the two sets of data have been constrained by the Bethe sum rule. The shape of the Bethe ridge given by the new data is broader than that obtained through the impulse approximation. The extrapolation to the optical limit (viz., at zero momentum transfer) is shown, and the reliability of these data is discussed in detail. C1 GSF Forschungszentrum Umwelt & Gesundheit, Inst Radiat Protect, D-85764 Neuherberg, Germany. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Dingfelder, M (reprint author), GSF Forschungszentrum Umwelt & Gesundheit, Inst Radiat Protect, Ingolstadter Landstr 1, D-85764 Neuherberg, Germany. EM dingfelder@gsf.de NR 8 TC 29 Z9 29 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD JUL PY 1999 VL 38 IS 2 BP 93 EP 96 DI 10.1007/s004110050143 PG 4 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA 223ND UT WOS:000081846400003 PM 10461754 ER PT J AU Seppala, T Vahatalo, J Auterinen, I Kosunen, A Nigg, DW Wheeler, FJ Savolainen, S AF Seppala, T Vahatalo, J Auterinen, I Kosunen, A Nigg, DW Wheeler, FJ Savolainen, S TI Modelling of brain tissue substitutes for phantom materials in neutron capture therapy (NCT) dosimetry SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID BEAM AB The aim of this study was to define the most suitable brain tissue phantom material for neutron capture therapy (NCT), The calculated distributions of the thermal neutron fluence and the fast neutron and gamma dose in normal brain tissue defined by ICRU were compared to those in four brain tissue substitutes: water; PMMA and two normal brain tissue substitute liquids, A and B, defined by us. Liquid B is an excellent material to simulate the neutron and gamma interactions in normal brain tissue and it can be considered for use in situations for which higher accuracy is required, although it may not be suitable for routine use. Water is a suitable brain tissue substitute for periodic epithermal beam calibration, for routine quality control and for intercomparison of beams in NCT dosimetry. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Helsinki, Cent Hosp, Dept Radiol, FIN-00029 Helsinki, Finland. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Univ Helsinki, Lab Radiochem, FIN-00014 Helsinki, Finland. Radiat & Nucl Safety Author, FIN-00881 Helsinki, Finland. Lockheed Martin Idaho Technol Co, Ctr BNCT Measurement & Dev, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Savolainen, S (reprint author), Univ Helsinki, Cent Hosp, Dept Radiol, POB 380, FIN-00029 Helsinki, Finland. NR 26 TC 16 Z9 17 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUL PY 1999 VL 55 IS 3 BP 239 EP 246 DI 10.1016/S0969-806X(98)00342-9 PG 8 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 214YV UT WOS:000081355900002 ER PT J AU Lee, EH Rao, GR Mansur, LK AF Lee, EH Rao, GR Mansur, LK TI LET effect on cross-linking and scission mechanisms of PMMA during irradiation SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID BEAM EXPOSURE CHARACTERISTICS; POLY(METHYL METHACRYLATE); RADIATION DEGRADATION; POLYMER MATERIALS; ION; SENSITIVITY; RESISTS AB Mechanisms of scission and cross-linking are investigated for poly(methyl methacrylate) subjected to various irradiation sources, such as low LET radiation sources (MeV e-beams, Co-60 gamma-rays) and high LET ions (MeV He+, Ar+). PMMA properties were degraded upon irradiation by e-beam and gamma-rays, but were improved upon bombardment with high energy ion beams (HEIB) as a result of cross-linking. The results indicate that high LET produces a high concentration of free radicals over many neighboring molecular chains, facilitating track overlap and enhancing cross-linking over scission, while low LET affects only a single molecular chain, leading to chain scission. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Lee, EH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 35 TC 80 Z9 80 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUL PY 1999 VL 55 IS 3 BP 293 EP 305 DI 10.1016/S0969-806X(99)00184-X PG 13 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 214YV UT WOS:000081355900008 ER PT J AU Johnson, KL Nath, J Brenner, DJ Geard, CR Tucker, JD AF Johnson, KL Nath, J Brenner, DJ Geard, CR Tucker, JD TI Chromosome aberrations of clonal origin in irradiated and unexposed individuals: Assessment and implications SO RADIATION RESEARCH LA English DT Article ID UPPER AERODIGESTIVE TRACT; FREQUENCY; RADIATION; ACCIDENT; TRANSLOCATIONS; EXPOSURE; VICTIMS; DAMAGE; CANCER; AGE AB Chromosome painting has proven useful for the detection of chromosomal rearrangements, although the presence of cells containing clonal aberrations can have an effect on the outcome of cytogenetic analyses (e.g. aberration frequency and chromosomal distribution studies), Cells with clonal chromosomal changes have been found in studies of both radiation-exposed Chernobyl cleanup workers ("liquidators") and healthy unexposed human subjects. We have used a simple statistical method to aid in the identification of individuals from distinct Chernobyl radiation-exposed and unexposed control populations who may possess cells containing clonal rearrangements. A chi(2) value determined from the observed number of aberrations and the expected number based on chromosome length that corresponds to a probability less than 0.005 appears to be an indicator of clonality, These selected individuals can be analyzed further for clonality, thereby sparing detailed examination of the entire population. Here we present an analysis of individuals possessing clonal aberrations to assess the influence of clonality on the results of cytogenetic studies. Our results show that the subtraction of clonal events from the chi(2) calculation for the "outliers" results in nearly all of these values losing their statistically significant deviation from proportionality. These adjustments can also be made to prevent the overestimation of frequencies of chromosome aberrations for biodosimetry. The frequency of clonal aberrations appears to increase as a function of age in control subjects, whereas an age effect was not evident in Chernobyl liquidators. This suggests that spontaneous and radiation-induced clonal expansion are occurring in control subjects and liquidators, respectively. (C) 1999 by Radiation Research Society. C1 Columbia Univ, Ctr Radiol Res, New York, NY 10032 USA. W Virginia Univ, Genet & Dev Biol Program, Morgantown, WV 26506 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Johnson, KL (reprint author), New England Med Ctr, Div Genet, 750 Washington St, Boston, MA 02111 USA. FU NCI NIH HHS [CA-49062]; NCRR NIH HHS [P41 RR-1 1623]; NIEHS NIH HHS [ES 07361] NR 18 TC 21 Z9 22 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 JUL PY 1999 VL 152 IS 1 BP 1 EP 5 DI 10.2307/3580043 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 213BP UT WOS:000081252400001 PM 10381835 ER PT J AU Narayanan, PK LaRue, KEA Goodwin, EH Lehnert, BE AF Narayanan, PK LaRue, KEA Goodwin, EH Lehnert, BE TI Alpha particles induce the production of interleukin-8 by human cells SO RADIATION RESEARCH LA English DT Article ID BRONCHIAL EPITHELIAL-CELLS; SISTER-CHROMATID EXCHANGES; HUMAN LUNG FIBROBLASTS; HYDROGEN-PEROXIDE; GENE-EXPRESSION; TRANSFORMING GROWTH-FACTOR-BETA-1; ENDOTHELIAL-CELLS; REACTIVE OXYGEN; ACTIVATION; NEUTROPHIL AB The pulmonary microenvironment is a primary target for alpha particles like those emitted by inhaled radon and its progeny, While exposure to alpha particles has recently been associated with the generation of extracellular and intracellular reactive oxygen species (ROS; Cancer Res. 57, 3963-3971, 1997), little is known about how exposure to alpha particles mag affect the generation of oxidative stress-related mediators in the respiratory tract. Interleukin-8 (IL8) is a cytokine recognized for its potent role as a chemoattractant and activator of polymorphonuclear leukocytes, Oxidative stress can up-regulate expression of the gene that encodes IL8 (IL8) in a variety of cell types, In this study, we set out to investigate a potential linkage between the generation of ROS and production of ILS in alpha-particle-irradiated normal human lung fibroblasts, ELISA revealed that exposure of the fibroblasts to low doses of alpha particles (3.6-19 cGy) caused significant increases in generation of the IL8 protein as early as 30 min after irradiation. Northern blot analyses revealed that such increases were associated with increased IL8 mRNA levels, Cells exposed to alpha particles in the presence of antioxidants, i.e. superoxide dismutase and dimethyl sulfoxide, resulted in significant decreases in extracellular IL8 protein levels. Similar results were obtained with cells treated with dexamethasone, an inhibitor of transcription, Our results indicate that alpha-particle-induced increases in production of ns occur temporally in parallel with elevated production of ROS, Conceivably, such production of ILS induced by a particles may contribute to an inflammatory response in the lower respiratory tract. Additionally, the promitogenic effects of IL8 may be a factor in hyperplastic responses in the airway epithelial cells to inhaled radon and radon progeny and perhaps other stresses associated with ROS, (C) 1999 br Radiation Research Society. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Cell & Mol Biol Grp, Los Alamos, NM 87545 USA. RP Lehnert, BE (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Cell & Mol Biol Grp, LS-4,MS-M888, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [P41-RR01315] NR 54 TC 137 Z9 145 U1 0 U2 5 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 JUL PY 1999 VL 152 IS 1 BP 57 EP 63 DI 10.2307/3580049 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 213BP UT WOS:000081252400007 PM 10381841 ER PT J AU Adelstein, SJ Fry, RJM AF Adelstein, SJ Fry, RJM TI Henry Irving Kohn (1909-1996) - In Memoriam SO RADIATION RESEARCH LA English DT Biographical-Item C1 Harvard Univ, Sch Med, Boston, MA 02115 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Adelstein, SJ (reprint author), Harvard Univ, Sch Med, Boston, MA 02115 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUL PY 1999 VL 152 IS 1 BP 98 EP 100 PG 3 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 213BP UT WOS:000081252400013 ER PT J AU Stewart, RD AF Stewart, RD TI On the complexity of the DNA damages created by endogenous processes SO RADIATION RESEARCH LA English DT Letter C1 Pacific NW Lab, Richland, WA 99352 USA. RP Stewart, RD (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. RI Stewart, Rob/A-2511-2009 NR 8 TC 11 Z9 11 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 JUL PY 1999 VL 152 IS 1 BP 101 EP 102 DI 10.2307/3580056 PG 2 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 213BP UT WOS:000081252400014 PM 10428681 ER PT J AU Phaneuf, RA Havener, CC Dunn, GH Muller, A AF Phaneuf, RA Havener, CC Dunn, GH Muller, A TI Merged-beams experiments in atomic and molecular physics SO REPORTS ON PROGRESS IN PHYSICS LA English DT Review ID ELECTRON-IMPACT EXCITATION; ABSOLUTE CROSS-SECTIONS; ION STORAGE-RING; ENHANCED DIELECTRONIC RECOMBINATION; STIMULATED RADIATIVE RECOMBINATION; ENERGY-LOSS TECHNIQUE; HIGHLY-CHARGED IONS; 3S(2) S-1->3S3P P-3; VERY-LOW ENERGIES; DISSOCIATIVE-RECOMBINATION AB The merged-beams technique is powerful for the experimental study of certain classes of atomic and molecular processes that cannot be as readily or accurately addressed by other methods. The principal advantages of the technique are the ability to make quantitative studies of collisional interactions with high resolution at low relative energies, to collect products that have undergone appreciable angular scattering, and to investigate processes involving short-lived or chemically-reactive species. Despite continuing advances in ion-source and particle-beam technologies, merged-beams experiments remain a challenge, constituting a relatively small but growing fraction of the worldwide effort in atomic and molecular collisions research. This review outlines the fundamental principles of the merged-beams method, reviews techniques and progress, and focuses on three active programs to highlight the advantages of the method for addressing fundamental questions in atomic and molecular physics. C1 Univ Nevada, Dept Phys, Reno, NV 89557 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Univ Giessen, Inst Kernphys, D-35392 Giessen, Germany. RP Phaneuf, RA (reprint author), Univ Nevada, Dept Phys, Reno, NV 89557 USA. RI Muller, Alfred/A-3548-2009 OI Muller, Alfred/0000-0002-0030-6929 NR 141 TC 72 Z9 72 U1 3 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0034-4885 J9 REP PROG PHYS JI Rep. Prog. Phys. PD JUL PY 1999 VL 62 IS 7 BP 1143 EP 1180 DI 10.1088/0034-4885/62/7/202 PG 38 WC Physics, Multidisciplinary SC Physics GA 221ZA UT WOS:000081756700002 ER PT J AU Phillips, F Ochs, L Schrock, M AF Phillips, F Ochs, L Schrock, M TI The product is dead - Long live the product-service! SO RESEARCH-TECHNOLOGY MANAGEMENT LA English DT Article; Proceedings Paper CT Portland International Conference on Management of Engineering and Technology (PICMET 97) CY JUL 27-31, 1997 CL PORTLAND, OREGON SP Portland State Univ, Engn Management Program, Univ Tokyo, Univ Cambridge, IEEE Engn Management Soc, IEEE Oregon Sect, INFORMS Technol Management Soc q, Japan Soc Sci Policy & Res Management, Washington Cty Reg Strategies Board, Multnomah Cty Reg Strategies Board, KVO Advertising & Public Relat AB optimize product cycle time, producers of high-tech products long ago began marketing before they had fully specified the product. Now, they may no longer finalize the physical specification at all. We can thus proclaim, "The product is dead, " which implies the substitution of expert service for features, information, and capabilities that used to be intrinsic to the tangible product. Companies are finding that dispensing with the idea of product remains one of the few ways-if not the only way-of compressing the technology cycle still further. By adapting to customers' needs and by reducing information overload a comprehensive package of tangible goods, service and information can serve customers better than a traditional product. C1 Oregon Grad Inst Sci & Technol, Dept Management Sci & Technol, Portland, OR USA. Pacific NW Lab, Richland, WA 99352 USA. Technol Innovat & Management Inc, Aloha, OR USA. Mentor Graph Corp, Wilsonville, OR USA. RP Phillips, F (reprint author), Oregon Grad Inst Sci & Technol, Dept Management Sci & Technol, Portland, OR USA. EM fphillips@admin.ogi.edu; lochs@admin.ogi.edu; michael_schrock@mentorg.com RI Phillips, Fred/O-8311-2014 NR 25 TC 9 Z9 9 U1 0 U2 4 PU INDUSTRIAL RESEARCH INST INC PI WASHINGTON PA 1550 M ST., NW, WASHINGTON, DC 20005 USA SN 0895-6308 J9 RES TECHNOL MANAGE JI Res.-Technol. Manage. PD JUL-AUG PY 1999 VL 42 IS 4 BP 51 EP 56 PG 6 WC Business; Engineering, Industrial; Management SC Business & Economics; Engineering GA 215LN UT WOS:000081383300011 ER PT J AU Lobo, RPSM LaVeigne, JD Reitze, DH Tanner, DB Carr, GL AF Lobo, RPSM LaVeigne, JD Reitze, DH Tanner, DB Carr, GL TI Performance of new infrared beamline U12IR at the National Synchrotron Light Source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID RADIATION; NSLS; SPECTROSCOPY AB The instrumentation and performance of the new infrared beamline U12IR at the National Synchrotron Light Source of Brookhaven National Laboratory is described. This beamline utilizes infrared synchrotron radiation from a bending magnet. A combination of beamline design features and spectroscopic instrumentation allows the facility to reach the extremely low frequency limit of similar to 2 cm(-1) (i.e., 60 GHz or a photon energy of 250 mu eV). The infrared light from the synchrotron emission at U12IR is compared to standard thermal sources and reveals substantial benefits for the study of small samples. In particular, the intensity of the synchrotron radiation in the far infrared can be as much as 200 times greater than that from a blackbody when millimeter-sized samples are measured. The effects of diffraction and noise on beamline performance are also discussed. (C) 1999 American Institute of Physics. [S0034-6748(99)02407-7]. C1 Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Lobo, RPSM (reprint author), Univ Florida, Dept Phys, Gainesville, FL 32611 USA. OI Lobo, Ricardo/0000-0003-2355-6856 NR 21 TC 26 Z9 27 U1 1 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 JUL PY 1999 VL 70 IS 7 BP 2899 EP 2904 DI 10.1063/1.1149846 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 210AC UT WOS:000081082100001 ER PT J AU Renner, O Patel, PK Wark, JS Krousky, E Young, PE Lee, RW AF Renner, O Patel, PK Wark, JS Krousky, E Young, PE Lee, RW TI Vertical variant of a double channel-cut crystal spectrometer for investigation of laser-generated plasmas SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID X-RAY SPECTROSCOPY; RESOLUTION; NOVA AB The theoretical design of multicrystal instruments which define a new class of spectrometers based on the vertical dispersion principle is reported together with experimental confirmation of design. Previous designs in the vertical-variant scheme-which have been fielded successfully in laser-produced plasma experiments-have operated with one or two crystal surfaces in a configuration that deflects the diffracted radiation back in the general direction of the source. The additional reflecting surfaces described here direct the radiation along a radial vector from the source to the detector, independent of the Bragg angle. Thus, the experimental setup is more flexible and greatly facilitates the coupling of the spectrometer to a charge-coupled device or streak camera. One of these instruments, a double channel-cut crystal spectrometer working in the vertical dispersion mode (DCCV), employs a total of four diffracting crystal surfaces. A compact design of the DCCV prototype is compatible with small bore reentrant diagnostic access tubes (e.g., the 6 in. manipulator) employed at several large-scale laser facilities. This high-dispersion spectrometer combines a high spectral resolution [R=13 500 with Si(111) crystals] with a one-dimensional spatial resolution of the order of 20 mu m. (C) 1999 American Institute of Physics. [S0034-6748(99)02707-0]. C1 Acad Sci Czech Republ, Inst Phys, Prague 18221, Czech Republic. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Renner, O (reprint author), Acad Sci Czech Republ, Inst Phys, Prague 18221, Czech Republic. RI Patel, Pravesh/E-1400-2011; Renner, Oldrich/C-1591-2010; Krousky, Eduard/G-8784-2014 OI Renner, Oldrich/0000-0003-4942-2637; NR 14 TC 4 Z9 4 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1999 VL 70 IS 7 BP 3025 EP 3031 DI 10.1063/1.1149863 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 210AC UT WOS:000081082100021 ER PT J AU Hoffman, CM Sinnis, C Fleury, P Punch, M AF Hoffman, CM Sinnis, C Fleury, P Punch, M TI Gamma-ray astronomy at high energies SO REVIEWS OF MODERN PHYSICS LA English DT Review ID VERY-HIGH-ENERGY; INTERGALACTIC INFRARED RADIATION; ATMOSPHERIC CHERENKOV-TELESCOPES; DISCRETE ASTROPHYSICAL SOURCES; ACTIVE GALAXY MARKARIAN-421; UNIDENTIFIED EGRET SOURCES; PRIMORDIAL BLACK-HOLES; COSMIC-RAYS; CRAB-NEBULA; SUPERNOVA-REMNANTS AB Progress in high-energy gamma-ray astronomy has depended upon the development of sophisticated detectors and analysis techniques. Observations in this decade using space-based and ground-based detectors have observed gamma-ray emission from a variety of sources. For the first time a consistent picture of the gamma-ray sky has emerged. This article describes the detection techniques in gamma-ray astronomy, the nature of the astrophysical objects studied, and the present state of the observations. Several possible new directions in the field are also described. [S0034-6861(99)00304-9]. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ecole Polytech, LPNHE, IN2P3, CNRS, F-75230 Paris, France. Coll France, PCC, IN2P3, CNRS, F-75231 Paris, France. RP Hoffman, CM (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. OI Punch, Michael/0000-0002-4710-2165 NR 231 TC 53 Z9 54 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD JUL PY 1999 VL 71 IS 4 BP 897 EP 936 DI 10.1103/RevModPhys.71.897 PG 40 WC Physics, Multidisciplinary SC Physics GA 226UA UT WOS:000082039400004 ER PT J AU Carena, M Culbertson, R Frisch, H Eno, S Mrenna, S AF Carena, M Culbertson, R Frisch, H Eno, S Mrenna, S TI Searches for supersymmetric particles at the Tevatron collider SO REVIEWS OF MODERN PHYSICS LA English DT Review ID GRAND UNIFIED THEORIES; LIGHTEST HIGGS-BOSON; ELECTROWEAK SYMMETRY-BREAKING; TOP-QUARK MASS; INFRARED FIXED-POINT; R-PARITY VIOLATION; CHARGINO-NEUTRALINO PRODUCTION; GAUGE COUPLING UNIFICATION; LARGE TAN-BETA; FERMILAB-TEVATRON AB The authors review the status of searches for supersymmetric particles at the Tevatron collider. After discussing the theoretical aspects relevant to the production and decay of supersymmetric particles at the Tevatron, the authors present the current results for runs Ia and Ib as of the summer of 1997. [S0034-6861(99)00404-3]. C1 Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Carena, M (reprint author), Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 250 TC 11 Z9 11 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD JUL PY 1999 VL 71 IS 4 BP 937 EP 981 DI 10.1103/RevModPhys.71.937 PG 45 WC Physics, Multidisciplinary SC Physics GA 226UA UT WOS:000082039400005 ER PT J AU Hwu, JJ Joy, DC AF Hwu, JJ Joy, DC TI A study of electron beam-induced conductivity in resists SO SCANNING LA English DT Article DE electron beam-induced conductivity; electron beam resists; scanning electron microscopy; charging; bias method ID CARRIER MOBILITY; INSULATORS; DIELECTRICS; COPOLYMER; DECAY AB The charging of polymeric resist materials during electron beam irradiation leads to significant problems during imaging and lithography processes. Charging occurs because of charge deposition in the polymer and charge generation/trapping due to formation of electron-hole pairs in the dielectric. The presence of such charge also results in the phenomena of electron beam-induced conductivity (EBIC). Electron beam-induced conductivity data have been obtained for three commercial e-beam resists under a variety of dose rate and temperature conditions. From the observed values of induced conductivity under varying conditions significant information about the generation of electron-hole pair and the transport of charge in the resist can be obtained. Three electron beam resists, EBR900, ZEP7000, and PBS are examined by an external bias method. The difference in resist chemistry is considered to play the role in the initial state EBIC behaviors among three resists even though the way that it affects the behaviors is not clear. A comparison of the power consumption comparison is proposed as a measure to give a preliminary estimate of the carrier concentration and carrier drift velocity differences among the resists. A simple single trap model with constant activation energy is proposed and provides good agreement with experiment. C1 Univ Tennessee, Dept Biochem, EM Facil, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Hwu, JJ (reprint author), Univ Tennessee, Dept Biochem, EM Facil, Knoxville, TN 37996 USA. NR 32 TC 9 Z9 9 U1 0 U2 3 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD JUL-AUG PY 1999 VL 21 IS 4 BP 264 EP 272 PG 9 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 227UQ UT WOS:000082098700006 PM 10483881 ER PT J AU Zelicoff, AP AF Zelicoff, AP TI Bioweapons research SO SCIENTIFIC AMERICAN LA English DT Letter C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Zelicoff, AP (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD JUL PY 1999 VL 281 IS 1 BP 8 EP + PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 208AE UT WOS:000080967400005 ER PT J AU Six, J Schultz, PA Jastrow, JD Merckx, R AF Six, J Schultz, PA Jastrow, JD Merckx, R TI Recycling of sodium polytungstate used in soil organic matter studies SO SOIL BIOLOGY & BIOCHEMISTRY LA English DT Article ID DENSITY FRACTIONATION; CARBON; SIZE; FATE C1 Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Katholieke Univ Leuven, Lab Soil Fertil & Soil Biol, B-3001 Heverlee, Belgium. RP Six, J (reprint author), Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. NR 14 TC 40 Z9 44 U1 5 U2 41 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-0717 J9 SOIL BIOL BIOCHEM JI Soil Biol. Biochem. PD JUL PY 1999 VL 31 IS 8 BP 1193 EP 1196 DI 10.1016/S0038-0717(99)00023-1 PG 4 WC Soil Science SC Agriculture GA 205EW UT WOS:000080809200013 ER PT J AU Wu, L Pan, L Mitchell, J Sanden, B AF Wu, L Pan, L Mitchell, J Sanden, B TI Measuring saturated hydraulic conductivity using a generalized solution for single-ring infiltrometers SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID EARLY-TIME; INFILTRATION; FLOW AB Saturated hydraulic conductivity is a measure of the ability of a soil to transmit water and is one of the most important soil parameters. New single-ring infiltrometer methods that use a generalized solution to measure the field saturated hydraulic conductivity (K-s) were developed and tested in this study. The K-s values can be calculated either from the whole cumulative infiltration curve (Method 1) or from the steady-state part of the cumulative infiltration curve by using a correction factor (Method 2), Numerical evaluation showed that the K-s values calculated from the simulated infiltration curves of representative soil textural types were in the range of 87 to 130% of the real K-s values, Field infiltration tests were conducted on an Arlington fine sandy Loam (coarse-loamy, mixed, thermic, Haplic Durixeralfs), The geometric means of the K-s values calculated from the field-measured infiltration curves by Method 1 and Method 2 were not significantly different, The geometric mean of the Ei,calculated from the detached core samples, however, was about twice that of the li,calculated from the infiltration curves, which was consistent with earlier findings. Unlike the earlier approaches, Method 1 calculates K-s values from the whole infiltration curve without assuming a filed relationship (alpha = K-s/phi(m)) between saturated hydraulic conductivity and matric flux potential phi(m). C1 Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Earth Sci, Berkeley, CA 95720 USA. Univ Calif, Ctr Agr, Parlier, CA 93648 USA. Univ Calif Coop Ext, Bakersfield, CA 93307 USA. RP Wu, L (reprint author), Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA. RI Pan, Lehua/G-2439-2015 NR 19 TC 41 Z9 41 U1 0 U2 10 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD JUL-AUG PY 1999 VL 63 IS 4 BP 788 EP 792 PG 5 WC Soil Science SC Agriculture GA 240NP UT WOS:000082832300008 ER PT J AU Rubin, M Powles, R von Rottkay, K AF Rubin, M Powles, R von Rottkay, K TI Models for the angle-dependent optical properties of coated glazing materials SO SOLAR ENERGY LA English DT Article ID FILMS; TRANSMITTANCE; INDEXES AB Optical transmittance and reflectance of window materials can be measured accurately at normal incidence using standard equipment. Sunlight often strikes at angles for which the transmittance and reflectance are significantly different from their values at normal incidence. A reliable procedure for extrapolating from normal properties to oblique properties is thus needed for accurate annual energy performance calculations and product comparisons. The structural models for the materials are greatly constrained by the limited amount of data that is usually available. For monolithic materials such as uncoated glass or plastic substrates it is possible to solve directly for the optical indices and then apply Fresnel's equation to obtain the oblique properties. For coated glass, the situation is more complex, but a numerical solution is often possible. First, detailed optical models were constructed and accurate angle-dependent data were generated for a wide selection of coated glazing materials. Then, a set of very simple thin-film models were chosen that would converse given a limited amount of data. At 60 degrees incidence, the monolithic model was often accurate to within 2% but frequently deviated farther up to 8%. The single-layer thin-film model fared little better. Highly constrained multilayer models often deviated less than 1% although convergence became increasingly specific to similar coating types. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Univ Giessen, Inst Phys 1, D-35392 Giessen, Germany. RP Rubin, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS2-300, Berkeley, CA 94720 USA. RI Powles, Rebecca/C-4272-2008 NR 23 TC 23 Z9 23 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-092X J9 SOL ENERGY JI Sol. Energy PD JUL PY 1999 VL 66 IS 4 BP 267 EP 276 DI 10.1016/S0038-092X(99)00029-8 PG 10 WC Energy & Fuels SC Energy & Fuels GA 220HJ UT WOS:000081658900002 ER PT J AU Cao, XA LaRoche, JR Ren, F Pearton, SJ Lothian, JR Singh, RK Wilson, RG Guo, HJ Pennycook, SJ AF Cao, XA LaRoche, JR Ren, F Pearton, SJ Lothian, JR Singh, RK Wilson, RG Guo, HJ Pennycook, SJ TI Implanted p-n junctions in GaN SO SOLID-STATE ELECTRONICS LA English DT Article ID TEMPERATURE; NITRIDES; INN; ALN AB Si-29(+) ion implantation into GaN(Mg), followed by rapid thermal annealing at 1100 degrees C was used to create n(+)/p junctions. The junction ideality factor was similar to 2, indicative of a high density of generation-recombination centers, and the breakdown voltage was 13 V at 5.1 x 10(-4) A cm(-2) Transmission electron microscopy revealed a high density (> 10(10) cm(-2)) of implantation damage-related dislocations in the material, due to incomplete annealing of displaced lattice atoms. Higher annealing temperatures and improved junction passivation are needed for improved stand-off voltages. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Multiplex Inc, S Plainfield, NJ 07080 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Ren, F (reprint author), Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NR 17 TC 12 Z9 12 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUL PY 1999 VL 43 IS 7 BP 1235 EP 1238 DI 10.1016/S0038-1101(99)00012-X PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 219BZ UT WOS:000081589200010 ER PT J AU Song, YQ Goodson, BM Pines, A AF Song, YQ Goodson, BM Pines, A TI NMR and MRI using laser-polarized xenon SO SPECTROSCOPY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; NOBLE-GAS MRI; HYPERPOLARIZED XE-129; CROSS-POLARIZATION; SURFACE NMR; ALPHA-CYCLODEXTRIN; POLYMER SURFACE; ADSORBED XENON; SPIN-EXCHANGE; LIQUID XENON AB The application of optical pumping methods increases the nuclear spin polarization of noble gases by four to five orders of magnitude. This enormous increase in polarization translates directly into greatly enhanced signals for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Selected experiments devised to exploit this enhanced sensitivity are reviewed, including xenon NMR/MRI studies of biological systems and polarization transfer to molecules in solution and on surfaces. C1 Schlumberger Doll Res Ctr, Ridgefield, CT 06877 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 65 TC 23 Z9 23 U1 1 U2 8 PU ADVANSTAR COMMUNICATIONS PI DULUTH PA 131 W FIRST ST, DULUTH, MN 55802 USA SN 0887-6703 J9 SPECTROSCOPY JI Spectroscopy PD JUL PY 1999 VL 14 IS 7 BP 26 EP 33 PG 8 WC Spectroscopy SC Spectroscopy GA 216AZ UT WOS:000081419500003 ER PT J AU Iyer, AN Salib, S Vipulanandan, C Salama, K Balachandran, U AF Iyer, AN Salib, S Vipulanandan, C Salama, K Balachandran, U TI Phase development and critical current density of Bi-2223 tapes fabricated by groove rolling SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID AG-SHEATHED TAPES; IN-TUBE METHOD; CA-CU-O; SUPERCONDUCTING TAPES; CORE DENSITY; MICROHARDNESS PROFILES; REACTION-KINETICS; DEFORMATION; POWDER; CONDUCTORS AB The powder-in-tube technique is the most widely used method for fabricating silver-clad Bi-2223 wires and tapes. In this method the silver biller containing the precursor material is transformed to the final shape using metallurgical deformation techniques such as wire drawing and flat rolling. In the present study, a modified version of the powder-in-tube technique was adopted where the silver biller was reduced in size by groove rolling instead of wire drawing. Microstructural analysis during the initial deformation stage revealed crack formation in the superconductor core. Stress conditions during groove rolling were analysed and appropriate changes were incorporated in the deformation process. After groove rolling the wires were flat rolled to a final thickness of 250 mu m. Subsequent thermomechanical treatment resulted in tapes with critical current density of approximate to 19 700 A cm(-2) (critical current of approximate to 40 A). C1 Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. McDermott Energy Serv, Houston, TX 77079 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Iyer, AN (reprint author), Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. NR 28 TC 6 Z9 6 U1 1 U2 4 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 JUL PY 1999 VL 12 IS 7 BP 436 EP 441 DI 10.1088/0953-2048/12/7/306 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 217XQ UT WOS:000081524600008 ER PT J AU Dauble, DD Johnson, RL Garcia, AP AF Dauble, DD Johnson, RL Garcia, AP TI Fall chinook salmon spawning in the tailraces of lower Snake River hydroelectric projects SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article AB We conducted studies from 1993 to 1997 to identify and characterize potential spawning habitat of "endangered" fall chinook salmon Oncorhynchus tshawytscha in areas downstream of four Snake River dams. This information was needed to provide guidelines for future operation of the lower Snake River hydroelectric system, including assessment of reservoir drawdown, and for site-specific construction planning. We used Geographic information System mapping technology to direct our initial search efforts. Suitable spawning habitat was defined based on physical habitat characteristics of the tailrace areas. Redd surveys were conducted in primary search areas and planned construction sites from mid-November through December with an underwater Video system. The survey path and redd locations were mapped by using a Global Positioning System. During the 4-year study, fall chinook salmon redds were found in the tailrace downstream of Lower Granite (LGR), Little Goose (LGO), and Ice Harbor (TK) dams. The redds were the first verified sightings of salmon spawning at their locations since these dams were constructed in 1970, 1975, and 1972, respectively. The total area used for spawning was about 2,560 m(2) for the LGR site and 580 m(2) for the LGO site. Only one redd was found downstream of the IPI project. Redds were in water from 4.0 to 8.1 m deep and on cobble substrate. All redds were adjacent to the outfall Row from juvenile fish bypass systems and on the powerhouse side of the river. Although temporal use was variable among individual projects, within-site fidelity was high. Tailrace spawning accounted for about 12% of the redds in the main stem of the Snake River during 1993 and 1994 but declined to less than 5% in 1996 and 1997. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. US Fish & Wildlife Serv, Idaho Fishery Resource Off, Ahsahka, ID 83520 USA. RP Dauble, DD (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 30 TC 20 Z9 20 U1 3 U2 6 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 1999 VL 128 IS 4 BP 672 EP 679 DI 10.1577/1548-8659(1999)128<0672:FCSSIT>2.0.CO;2 PG 8 WC Fisheries SC Fisheries GA 351XB UT WOS:000089183800012 ER PT J AU Martinez, MJ Nilson, RH AF Martinez, MJ Nilson, RH TI Estimates of barometric pumping of moisture through unsaturated fractured rock SO TRANSPORT IN POROUS MEDIA LA English DT Article DE barometric pumping; two-phase flow; fractured rock ID TRANSPORT AB We present a theory for the motion of water vapor at depth in a discretely fractured permeable medium induced by atmospheric barometric pressure fluctuations, or 'barometric pumping'. The theory involves multiphase mass and energy transport in a fracture/matrix system, with discrete representation of the fracture system. The barometric pressure fluctuations are approximated as periodic in time, with amplitude corresponding to measured values. To simplify the analysis, a 'single-horizon' approximation is applied in which the time-mean gradient is used to evaluate the vertical advective flux in the fractures. Time-periodic solutions are obtained numerically, enabling the calculation of the net efflux of moisture per cycle. The model is applied to material representative of the Yucca Mountain region of southwestern Nevada. The results indicate that the efflux of moisture carried upward from significant depths by barometric pumping is much less than the near surface efflux that is commonly estimated by assuming that air enters the medium dry and is returned to the atmosphere fully saturated with water vapor. This near surface efflux consists primarily of moisture discharged from the upper layer which is frequently replenished by precipitation. Of greater interest to nuclear waste repository design and estimations of net infiltration in arid regions is the fraction of the total moisture efflux that comes from significant depths. This deep transport is quantified by the fracture/matrix transport model described here. Although the transport by barometric pumping from depth is small compared to the total moisture expelled from the surface layer, it is an order of magnitude greater than the vertical moisture flux carried from depth by diffusion. C1 Sandia Natl Labs, Engn Sci Ctr, Albuquerque, NM 87185 USA. Sandia Natl Labs, Combust & Phys Sci Ctr, Albuquerque, NM 87185 USA. RP Martinez, MJ (reprint author), Sandia Natl Labs, Engn Sci Ctr, POB 5800, Albuquerque, NM 87185 USA. NR 18 TC 11 Z9 12 U1 1 U2 2 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 JUL PY 1999 VL 36 IS 1 BP 85 EP 119 DI 10.1023/A:1006593628835 PG 35 WC Engineering, Chemical SC Engineering GA 199CJ UT WOS:000080461500005 ER PT J AU Liu, CX Ball, WP AF Liu, CX Ball, WP TI Application of inverse methods to contaminant source identification from aquitard diffusion profiles at Dover AFB, Delaware SO WATER RESOURCES RESEARCH LA English DT Article ID RELATIVE ENTROPY INVERSION; GROUNDWATER CONTAMINANT; RELEASE HISTORY; PARAMETER-ESTIMATION; PLUME; MEDIA; FLOW AB This paper presents a refinement and expansion of our previously described efforts to estimate contaminant plume history from observed contaminant concentrations within a low-permeability aquitard at the site of a field-scale groundwater remediation experiment at Dover Air Force Base. At this site, a two-layer aquitard has been contaminated with tetrachloroethene and trichloroethene through diffusive mass transfer from an overlying contaminated aquifer. Measurements of contaminant concentrations in the aquitard are used, together with independently obtained information about the sorption and diffusion properties of the aquitard medium, to estimate the timewise variation of the boundary concentration at the interface between the aquitard and aquifer, thus providing evidence related to the overlying plume history. In our refined analysis, we assume the contaminant source history to be a function of time with unknown form, and we supplement our interpretations with a second coring result at a different location. The results demonstrate how "forensic" interpretations of this kind can provide useful and important information regarding the contaminant release history at sites of groundwater contamination and cleanup; however, the results also show that the forensic problem is a highly nonunique problem associated with potentially large uncertainty. Interpretation of the estimated results therefore requires careful consideration in the context of other available information. C1 Pacific NW Lab, Richland, WA 99352 USA. Johns Hopkins Univ, Dept Geog & Environm Engn, Baltimore, MD 21218 USA. RP Liu, CX (reprint author), Pacific NW Lab, Mail Stop K8-96,POB 999, Richland, WA 99352 USA. RI Liu, Chongxuan/C-5580-2009; Ball, William/A-3285-2010 OI Ball, William/0000-0001-5217-8108 NR 39 TC 62 Z9 63 U1 1 U2 21 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 JUL PY 1999 VL 35 IS 7 BP 1975 EP 1985 DI 10.1029/1999WR900092 PG 11 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400003 ER PT J AU Shan, C Javandel, I Witherspoon, PA AF Shan, C Javandel, I Witherspoon, PA TI Characterization of leaky faults: Study of air flow in faulted vadose zones SO WATER RESOURCES RESEARCH LA English DT Article ID PERMEABILITY AB Characterization of leaky faults in vadose zones of large thickness is very important for engineering problems such as high-level nuclear waste disposal. This paper presents analytical solutions for air flow in faulted vadose zones of large or small thicknesses. The focus is on those sites where the fault zone is more permeable than its adjacent rock matrix. On the basis of the assumptions of a two-dimensional air flow in the matrix and a one-dimensional air flow in the fault zone, analytical solutions are presented for a sinusoidal atmospheric pressure variation. A procedure is then provided for extending the application of the solutions to an arbitrary atmospheric pressure variation. The solutions can help determine air permeability of leaky faults in the vadose zone. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Shan, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. NR 15 TC 6 Z9 7 U1 0 U2 3 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 JUL PY 1999 VL 35 IS 7 BP 2007 EP 2013 DI 10.1029/1999WR900037 PG 7 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400005 ER PT J AU Jardine, PM Sanford, WE Gwo, JP Reedy, OC Hicks, DS Riggs, JS Bailey, WB AF Jardine, PM Sanford, WE Gwo, JP Reedy, OC Hicks, DS Riggs, JS Bailey, WB TI Quantifying diffusive mass transfer in fractured shale bedrock SO WATER RESOURCES RESEARCH LA English DT Article ID CONTROLLING SUBSURFACE TRANSPORT; HETEROGENEOUS POROUS-MEDIA; OIL-RECOVERY MEOR; SOLUTE TRANSPORT; TRACER EXPERIMENTS; STORM EVENTS; RADIONUCLIDE MIGRATION; UPPER SUBCATCHMENT; AQUIFER SEDIMENTS; NATURAL-GRADIENT AB A significant limitation in defining remediation needs at contaminated sites often results from an insufficient understanding of the transport processes that control contaminant migration. The objectives of this research were to help resolve this dilemma by providing an improved understanding of contaminant transport processes in highly structured, heterogeneous subsurface environments that are complicated by fracture flow and matrix diffusion. Our approach involved a unique long-term, steady state natural gradient injection of multiple tracers with different diffusion coefficients (Br, He, Ne) into a fracture zone of a contaminated shale bedrock. The spatial and temporal distribution of the tracers was monitored for 550 days using an array of groundwater sampling wells instrumented within a fast flowing fracture regime and a slow flowing matrix regime. The tracers were transported preferentially along strike-parallel fractures, with a significant portion of the tracer plumes migrating slowly into the bedrock matrix. Movement into the matrix was controlled by concentration gradients established between preferential flow paths and the adjacent rock matrix. Observed differences in tracer mobility into the matrix were found to be a function of their free-water molecular diffusion coefficients. The multiple tracer technique confirmed that matrix diffusion was a significant process that contributed to the overall physical nonequilibrium that controlled contaminant transport in the shale bedrock. The experimental observations were consistent with numerical simulations of the multitracer breakthrough curves using a simple fracture flow model. The simulated results also demonstrated the significance of contaminant diffusion into the bedrock matrix. The multiple tracer technique and ability to monitor the fracture and matrix regimes provided the necessary experimental constraints for the accurate numerical quantification of the diffusive mass transfer process. The experimental and numerical results of the tracer study were also consistent with indigenous contaminant discharge concentrations within the fracture and matrix regimes of the field site. These findings suggest that the secondary source contribution of the bedrock matrix to the total off-site transport of contaminants is relatively large and potentially long-lived. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Colorado State Univ, Dept Earth Resources, Ft Collins, CO 80521 USA. Oak Ridge Natl Lab, Ctr Computat Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Instruments & Control Div, Oak Ridge, TN 37831 USA. RP Jardine, PM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Sanford, William/F-7380-2016 OI Sanford, William/0000-0001-9085-1367 NR 72 TC 75 Z9 76 U1 5 U2 49 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 JUL PY 1999 VL 35 IS 7 BP 2015 EP 2030 DI 10.1029/1999WR900043 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400006 ER PT J AU Wood, BD Kavvas, ML AF Wood, BD Kavvas, ML TI Ensemble-averaged equations for reactive transport in porous media under unsteady flow conditions SO WATER RESOURCES RESEARCH LA English DT Article ID NONSTATIONARY VELOCITY-FIELDS; NATURAL GRADIENT EXPERIMENT; SOLUTE TRANSPORT; HETEROGENEOUS AQUIFERS; STOCHASTIC-ANALYSIS; HYDRAULIC CONDUCTIVITY; PERTURBATION EXPANSION; LAGRANGIAN ANALYSIS; CUMULANT EXPANSION; SAND AQUIFER AB We present a method for deriving the ensemble-averaged reactive solute transport equation for unsteady, non-divergence-free flow field conditions. Our approach uses a cumulant expansion, Lie group theory, and time-ordered exponentials to develop the ensemble-averaged transport equation. The cumulant expansion is in powers of a alpha tau(c), where alpha measures the magnitude of the perturbations of the transport and reaction operators and tau(c) is the correlation time of these perturbations. Because the cumulant expansion avoids secular terms (terms in powers of time), the problem can be closed by rationally truncating the expansion. The truncated terms can be shown to be of lower order than those terms that are kept, provided that a particular constraint (in terms of the Kubo number) is met. The use of Lie group theory allows one to automatically combine the Eulerian and Lagrangian approaches. A particular time-ordered exponential that arises in the analysis can be interpreted as a translation operator that possesses a well-defined algebra. These translation operators appear in the second-order (covariance) terms of the cumulant expansion, and their effect is to shift one of the terms of the covariance functions relative to the other along the trajectory formed by the ensemble-averaged velocity field. This approach does not require neglecting the local dispersion tensor and has the advantage that no integral transformations are conducted; therefore all results are expressed in terms of real space variables. C1 Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA. RP Wood, BD (reprint author), Pacific NW Lab, MS K3-61,POB 999, Richland, WA 99352 USA. RI Wood, Brian/K-4025-2012; Wood, Brian/J-8362-2013 OI Wood, Brian/0000-0003-3152-7852; Wood, Brian/0000-0003-3152-7852 NR 80 TC 17 Z9 17 U1 0 U2 3 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 JUL PY 1999 VL 35 IS 7 BP 2053 EP 2068 DI 10.1029/1999WR900113 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400009 ER PT J AU Wood, BD Kavvas, ML AF Wood, BD Kavvas, ML TI Stochastic solute transport under unsteady flow conditions: Comparison of theory, Monte Carlo simulations, and field data SO WATER RESOURCES RESEARCH LA English DT Article ID NATURAL GRADIENT EXPERIMENT; HETEROGENEOUS POROUS-MEDIA; BORDEN TRACER-TEST; LAGRANGIAN ANALYSIS; SPATIAL MOMENTS; SAND AQUIFER; HYDRAULIC CONDUCTIVITY; GROUNDWATER-FLOW; DISPERSION; SITE AB In this, the second of two papers concerning the stochastic description of solute transport under unsteady flow conditions, we show how the ensemble-averaged solute transport equation derived in the companion paper [Wood and Kavvas, this issue] can be solved. A two-dimensional analysis is conducted under conditions that are representative of the Borden aquifer, and a solution to the ensemble-averaged solute transport equation is found numerically. The analytical model suggested by Dagan et al. [1996] is adopted for the velocity field mean and Lagrangian covariance functions. The numerical solution provides the ensemble-averaged concentration field under transient flow conditions; from this concentration field the first- and second-order moments of the ensemble-averaged solute plume are calculated. The ensemble-averaged plume moments compare favorably with the moments calculated using the approach of Dagan et al. [1996], with the plume moments from a Monte Carlo analysis, and with plume moments measured in the field. In our approach the Darcy-scale dispersion is not neglected, and it is shown that this dispersion term has a small but significant influence on the resulting solutions. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA. RP Wood, BD (reprint author), Pacific NW Lab, MS K3-61,POB 999, Richland, WA 99352 USA. RI Wood, Brian/K-4025-2012; Wood, Brian/J-8362-2013 OI Wood, Brian/0000-0003-3152-7852; Wood, Brian/0000-0003-3152-7852 NR 39 TC 13 Z9 13 U1 0 U2 2 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 JUL PY 1999 VL 35 IS 7 BP 2069 EP 2084 DI 10.1029/1999WR900112 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400010 ER PT J AU Ryon, RW Ruhter, WD AF Ryon, RW Ruhter, WD TI Uranium and plutonium solution assays by transmission-corrected X-ray fluorescence spectrometry SO X-RAY SPECTROMETRY LA English DT Article; Proceedings Paper CT European Conference on Energy Dispersive X-Ray Spectrometry 1998 (EDXRS-98) CY JUN 07-12, 1998 CL BOLOGNA, ITALY AB An x-ray fluorescence analysis technique was developed for uranium and plutonium solutions, which compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays, Co-57 is used to excite efficiently the K lines of the elements, and a mixed Co-57 plus Gd-153 transmission source is used to correct for variations in absorption. The absorption correction is a unique feature of the technique which permits accurate calibration with a single solution standard and the measurement of a wide range of concentrations (up to 300 g l(-1)). Without this correction procedure, up to six solution standards are required to correct for non-linearity over this concentration range. In addition, other elements present in the specimens and not present in the standards would otherwise reduce the accuracy or even invalidate the analyses. Specially designed equipment incorporates a planar intrinsic germanium detector, excitation and transmission radioisotopes and specimen holder. The apparatus can be inserted into a rubber glove of a glove-box, keeping the apparatus outside and the solutions inside the glove-box, thereby protecting the user and the equipment from possible contamination, This technique will be tested at the Bochvar Institute of Inorganic Materials in Moscow for possible use in the Russian complex of nuclear facilities. This is part of a cooperative program between laboratories in the USA and Russia to strengthen systems of nuclear materials protection, control and accountability (MPC&A) in both countries. A part of this program is to measure accurately and track inventories of materials, hence the need for good non-destructive analytical techniques. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Isotope Sci Div L 231, Livermore, CA 94551 USA. RP Ryon, RW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Isotope Sci Div L 231, POB 808, Livermore, CA 94551 USA. NR 6 TC 4 Z9 4 U1 0 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD JUL-AUG PY 1999 VL 28 IS 4 BP 230 EP 232 PG 3 WC Spectroscopy SC Spectroscopy GA 220XH UT WOS:000081693400005 ER PT J AU Kregsamer, P Streli, C Wobrauschek, P Gatterbauer, H Pianetta, P Palmetshofer, L Brehm, LL AF Kregsamer, P Streli, C Wobrauschek, P Gatterbauer, H Pianetta, P Palmetshofer, L Brehm, LL TI Synchrotron radiation-excited glancing incidence XRF for depth profile and thin-film analysis of light elements SO X-RAY SPECTROMETRY LA English DT Article; Proceedings Paper CT European Conference on Energy Dispersive X-Ray Spectrometry 1998 (EDXRS-98) CY JUN 07-12, 1998 CL BOLOGNA, ITALY ID X-RAY-FLUORESCENCE; REFLECTION AB First results of depth profile and thin-film analysis by glancing incidence x-ray fluorescence analysis of low-Z elements (carbon to aluminum), usually not detectable by conventional instruments, were obtained by synchrotron radiation excitation (SSRL, Beamline III-4) and by a special energy-dispersive spectrometer with high efficiency for low-energy fluorescence radiation [Ge(HP) detector with an ultra-thin 300 nm entrance window]. The results of calculations taking into account several sample parameters of interest agree with the measurements, Results are presented for the determination of depth profiles of Na, Mg and Al implanted in Si wafers and for thin films of Al and a C bulk sample. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Vienna, Atominst, A-1020 Vienna, Austria. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Univ Linz, Inst Halbleiter & Featkorperphys, A-4040 Linz, Austria. Dow Chem Co USA, Midland, MI 48667 USA. RP Kregsamer, P (reprint author), Univ Vienna, Atominst, Schuttelstr 115, A-1020 Vienna, Austria. OI Streli, Christina/0000-0002-5141-3177 NR 9 TC 11 Z9 13 U1 0 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD JUL-AUG PY 1999 VL 28 IS 4 BP 292 EP 296 DI 10.1002/(SICI)1097-4539(199907/08)28:4<292::AID-XRS354>3.3.CO;2-1 PG 5 WC Spectroscopy SC Spectroscopy GA 220XH UT WOS:000081693400015 ER PT J AU Hershler, R Mulvey, M Liu, HP AF Hershler, R Mulvey, M Liu, HP TI Biogeography in the Death Valley region: evidence from springsnails (Hydrobiidae : Tryonia) SO ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY LA English DT Article DE Colorado River; phylogenetic relationships; evolution; mitochondrial DNA; allozymes; gastropoda; pupfish; Cyprinodon ID SNAIL BIOMPHALARIA-GLABRATA; MITOCHONDRIAL-DNA VARIATION; GENETIC-VARIATION; COLORADO RIVER; SYSTEM; CALIFORNIA; CYPRINODONTIDAE; POPULATIONS; GASTROPODA; EVOLUTION AB Allozyme and mitochondrial DNA variation were analysed to examine evolution of the nine species of springsnails (genus Tryonia) living in the Death Valley system (Owens and Amargosa basins) of southeastern California and southwestern Nevada. Both allozyme and mtDNA evidence indicate that this highly endemic fauna is non-monophyletic. Species from the upper Amargosa basin comprise a clade most closely related to snails living in the Colorado basin. Snails from the lower Amargosa basin (Death Valley trough) reflect a complex evolutionary history and two of these species are more closely related to an estuarine species from western California than to other snails of the region. These results indicate a commonality of pattern with the well-studied Death Valley pupfishes (Cyprinodon), which also are non-monophyletic and include species that are most closely related to Colorado basin congeners. These biogeographic patterns are interpreted within the context of a recently proposed model for the early history of the lower Colorado River. (C) 1999 The Linnean Society of London. C1 Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Hershler, R (reprint author), Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. NR 55 TC 24 Z9 24 U1 1 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0024-4082 J9 ZOOL J LINN SOC-LOND JI Zool. J. Linn. Soc. PD JUL PY 1999 VL 126 IS 3 BP 335 EP 354 DI 10.1111/j.1096-3642.1999.tb01375.x PG 20 WC Zoology SC Zoology GA 218FE UT WOS:000081541900004 ER PT J AU Lavielle, B Marti, K Jeannot, JP Nishiizumi, K Caffee, M AF Lavielle, B Marti, K Jeannot, JP Nishiizumi, K Caffee, M TI The Cl-36-Ar-36-K-40-K-41 records and cosmic ray production rates in iron meteorites SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE cosmochemistry; iron meteorites; isotope ratios; stable isotopes; exposure age; cosmogenic elements; noble gases; radioactive isotopes ID PROTON-INDUCED REACTIONS; EXPOSURE AGES; ELEMENTS 6-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-29; NUCLIDE PRODUCTION; METEOROID SIZES; ENERGY-RANGE; AL-26; BE-10; SPALLATION; POTASSIUM AB This is the first contribution towards a reevaluation of exposure histories of iron meteorites and of the constancy of the cosmic ray flux over the last billion years, as recorded in these fossil detectors. We have performed new Cl-36, Al-26, Be-10, and noble gas measurements, including determination of the shielding parameter, S = He-4/Ne-21, in samples with published K data, The K isotopic data, coupled to Ar-36 and Cl-36 concentrations permit selection of meteorites which have only experienced simple (constant geometry) irradiation histories. These objects can be used for the calibration of shielding-dependent production rates within these metallic detectors. Tn order to carry out production rate calibrations based on K-40-K-41 data, we assume constancy of the cosmic flux during the interval 150 to 700 My ago. We note that meteorites with very old potassium ages cannot be included in this calibration, as these meteorites require distinct parameter sets. A calibration data set representing a total of 13 meteorites was used to compute long-term (0.5 Gy) average production rates, These average production rates of Cl-36 from this particular calibration set are significantly (28%) lower than those determined for the recent (less than or equal to 10 My) cosmic ray flux. We also document here the quality of the resulting potassium production rate parameter Mo(S) with a calculated isochron for irons of group IVA. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Bordeaux 1, CNRS, URA 451, Ctr Etud Nucl Bordeaux Gradignan, F-33175 Gradignan, France. Univ Calif San Diego, Dept Chem, La Jolla, CA 92093 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Div, Livermore, CA 94550 USA. RP Lavielle, B (reprint author), Univ Bordeaux 1, CNRS, URA 451, Ctr Etud Nucl Bordeaux Gradignan, BP 120, F-33175 Gradignan, France. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 38 TC 80 Z9 84 U1 0 U2 4 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 JUN 30 PY 1999 VL 170 IS 1-2 BP 93 EP 104 DI 10.1016/S0012-821X(99)00099-0 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 206QL UT WOS:000080890500008 ER PT J AU Bryan, JC Sachleben, RA Hay, BP AF Bryan, JC Sachleben, RA Hay, BP TI Structural aspects of cesium ion selectivity by tetrabenzo-24-crown-8 SO INORGANICA CHIMICA ACTA LA English DT Article DE crystal structures; molecular mechanics; cesium complexes; crown ether complexes ID MM3(96) FORCE-FIELD; CROWN-ETHERS; CONFORMATIONAL-ANALYSIS; NITRATE SOLUTIONS; RATIONAL DESIGN; DONOR GROUPS; EXTRACTION; COMPLEXES; LIGANDS; ALKALI AB The structural origins of the selectivity of the cesium ion over other alkali metal ions by tetrabenzo-24-crown-8 are investigated using molecular mechanics and single crystal X-ray diffraction. The structures containing Cs+ and Rb+ are the first reported for these ions with any 24-crown-8 ether. The same crown conformation is observed for Cs+, Rb+ and acetonitrile as guests, suggesting that this binding conformation is relatively low energy and inflexible. A different, higher energy, crown conformation is observed in the Na+ structure. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM bryanjc@ornl.gov NR 39 TC 22 Z9 22 U1 0 U2 3 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 JUN 30 PY 1999 VL 290 IS 1 BP 86 EP 94 DI 10.1016/S0020-1693(99)00119-X PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 209TE UT WOS:000081064300012 ER PT J AU Liska, R Wendroff, B AF Liska, R Wendroff, B TI Two-dimensional shallow water equations by composite schemes SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE shallow water equations; composite schemes; conservation laws; Lax-Friedrichs scheme; Lax-Wendroff scheme ID MODEL AB Composite schemes are formed by global composition of several Lax-Wendroff steps followed by a diffusive Lax-Friedrichs or WENO step, which filters out the oscillations around shocks typical for the Lax-Wendroff scheme. These schemes are applied to the shallow water equations in two dimensions. The Lax-Friedrichs composite is also formulated for a trapezoidal mesh, which is necessary in several example problems. The suitability of the composite schemes for the shallow water equations is demonstrated on several examples, including the circular dam break problem, the shock focusing problem and supercritical channel flow problems. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Czech Tech Univ, Fac Nucl Sci & Phys Engn, CR-11519 Prague 1, Czech Republic. Univ Calif Los Alamos Natl Lab, Grp T7, Los Alamos, NM 87544 USA. RP Liska, R (reprint author), Czech Tech Univ, Fac Nucl Sci & Phys Engn, Brehova 7, CR-11519 Prague 1, Czech Republic. RI Liska, Richard/C-3142-2009 OI Liska, Richard/0000-0002-6149-0440 NR 17 TC 40 Z9 42 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD JUN 30 PY 1999 VL 30 IS 4 BP 461 EP 479 DI 10.1002/(SICI)1097-0363(19990630)30:4<461::AID-FLD850>3.0.CO;2-4 PG 19 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA 211HJ UT WOS:000081154600005 ER PT J AU Bhupathiraju, VK Hernandez, M Krauter, P Alvarez-Cohen, L AF Bhupathiraju, VK Hernandez, M Krauter, P Alvarez-Cohen, L TI A new direct microscopy based method for evaluating in-situ bioremediation SO JOURNAL OF HAZARDOUS MATERIALS LA English DT Article DE metabolic activity; anaerobic; 5-cyano-2,3-ditolyl tetrazolium chloride (CTC); in-situ bioremediation; 5-(4,6-dichlorotriazinyl) aminofluoroscein (DTAF) ID 5-CYANO-2,3-DITOLYL TETRAZOLIUM CHLORIDE; RESPIRATORY ACTIVITY; DRINKING-WATER; SUBSURFACE SEDIMENTS; RESPIRING BACTERIA; METABOLIC-ACTIVITY; ACTIVATED-SLUDGE; ESCHERICHIA-COLI; FLOW-CYTOMETRY; COUNT METHODS AB A new epifluorescent microscopy based method using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and 5-(4,6-dichlorotriazinyl) aminofluoroscein (DTAF) was developed for quantifying total microbial biomass and evaluating levels of microbial activity. CTC is a tetrazolium dye that forms fluorescent intracellular formazan when biologically reduced by components of the electron transport system and/or dehydrogenases of metabolically active bacteria. DTAF is a fluorescein-based fluorochrome that selectively stains bacterial cell walls thereby enabling quantification of total bacterial biomass. CTC can be used in conjunction with DTAF to provide the optical resolution necessary to differentiate metabolically active cells from inactive cells in microbial populations associated with subsurface soils. The CTC/DTAF staining method has been shown to be effective for quantifying the metabolic activity of not only aerobic bacteria, but also diverse groups of anaerobic bacteria. This method allows for the rapid quantification of total and active bacterial numbers in complex soil samples without enrichment or cell elution. In this study, CTC/DTAF staining was applied to evaluate in-situ microbial activity in petroleum hydrocarbon contaminated subsurface soils from Sites 3 and 13 at Alameda Point, CA. At each site, subsurface microbial activity at two locations within contaminated plumes were examined and compared to activity at two geologically similar but uncontaminated background locations. Significant bacterial populations were detected in all soils examined, and the biomass estimates were several orders of magnitude higher than those obtained by conventional culture-based techniques. Both the total bacterial concentrations and the numbers of active bacteria in soils from contaminated areas were substantially higher than those observed in soils from background locations. Additionally, the percentages of metabolically active bacteria in the contaminated areas were consistently higher than those detected in background areas, suggesting that the enhanced microbial activity was due to microbial contaminant degradation. Although conventional heterotrophic plate counts failed to show significant microbial activity at either of the sites, soil gas carbon dioxide and methane measurements confirmed that hydrocarbon contaminant degradation was occurring in both areas. The CTC/DTAF staining protocol proved to be a rapid, reliable, and inexpensive method to evaluate the progress of in-situ bioremediation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. Univ Colorado, Dept Civil Environm & Architectural Engn, Boulder, CO 80309 USA. Univ Calif Lawrence Livermore Natl Lab, Environm Protect Dept, Livermore, CA 94550 USA. RP Alvarez-Cohen, L (reprint author), Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. FU NIEHS NIH HHS [P42-ES04705] NR 55 TC 26 Z9 27 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3894 J9 J HAZARD MATER JI J. Hazard. Mater. PD JUN 30 PY 1999 VL 67 IS 3 BP 299 EP 312 DI 10.1016/S0304-3894(99)00045-X PG 14 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 210LU UT WOS:000081107600005 PM 10370182 ER PT J AU Milewski, JO Dickerson, PG Nemec, RB Lewis, GK Fonseca, JC AF Milewski, JO Dickerson, PG Nemec, RB Lewis, GK Fonseca, JC TI Application of a manufacturing model for the optimization of additive processing of Inconel alloy 690 SO JOURNAL OF MATERIALS PROCESSING TECHNOLOGY LA English DT Article DE computer aided design and manufacture; directed light fabrication; Inconel alloy 690; laser; metal powder AB Directed light fabrication (DLF) is an additive processing method that fuses metal powders, delivered by inert gas into the focal zone of a high powered laser beam, to form a fully dense metal deposit. Computer aided design and manufacturing (CAD/CAM) was used to simulate and specify the metal deposition process for the formation of a three dimensional part using Inconel alloy 690. This study demonstrates the ability to directly fabricate a complex, near net shaped object using a DLF machine with an alloy that is difficult and costly to fabricate using conventional processing methods. The fabrication of a monolithic hexagonal shape with through holes is described with the associated CAD/CAM additive processing case study, metallographic examination, and part characterization. The deposition of a fully dense nickel base alloy component was performed and achieved a high degree of dimensional accuracy. A comparison between the DLF deposited shape and the original part definition illustrates that near-net-shape tolerance levels are attainable within a 0.1 mm envelope. The single step production of fully dense, near net shaped, three dimensional metal parts directly from a computer based manufacturing model is compared with conventional processing methods currently available. As a result, significant process flexibility - beyond that of conventional processing capabilities is recognized - with potentially lower production costs, higher quality components, and the realization of higher performance designs. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. SyntheMet Corp, Los Alamos, NM 87544 USA. RP Milewski, JO (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS G770, Los Alamos, NM 87545 USA. NR 13 TC 27 Z9 30 U1 3 U2 25 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-0136 J9 J MATER PROCESS TECH JI J. Mater. Process. Technol. PD JUN 30 PY 1999 VL 91 IS 1-3 BP 18 EP 28 DI 10.1016/S0924-0136(98)00412-9 PG 11 WC Engineering, Industrial; Engineering, Manufacturing; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 228YC UT WOS:000082164300003 ER PT J AU Li, X Wang, LS Boldyrev, AI Simons, J AF Li, X Wang, LS Boldyrev, AI Simons, J TI Tetracoordinated planar carbon in the Al4C- anion. A combined photoelectron spectroscopy and ab initio study SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ZIRCONIUM ALUMINUM COMPLEXES; MOLECULAR-ORBITAL METHODS; GAUSSIAN-BASIS SETS; ELECTRONIC-STRUCTURE; IONIZATION ENERGIES; TRIPLE-BOND; STABILIZATION; CLUSTERS; ATOMS; DILITHIOMETHANE AB The chemical structure and bonding of Al4C and Al4C- have been studied by photoelectron spectroscopy and ab initio calculations. While ALC is known to be a tetrahedral molecule, the data reported here suggest that Al4C- has D-4h symmetry (when averaged over zero-point vibrational motions) and thus is the smallest species identified to date that contains a tetracoordinated planar carbon atom. The experimental vertical electron detachment energy of Al4C- (2.65 +/- 0.06 eV) compares well to 2.71 eV calculated at the CCSD(T)/6-311+G(2df) level of theory. The excellent agreement between the calculated and experimental electron detachment energies, excitation energies, and other spectral features allows us to elucidate the structure of the tetracoordinated planar-carbon-containing Al4C- anion. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. RI Boldyrev, Alexander/C-5940-2009 OI Boldyrev, Alexander/0000-0002-8277-3669 NR 69 TC 181 Z9 183 U1 3 U2 23 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 JUN 30 PY 1999 VL 121 IS 25 BP 6033 EP 6038 DI 10.1021/ja9906204 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 212KX UT WOS:000081216800023 ER PT J AU Ilangovan, U Wojciak, JM Connolly, KM Clubb, RT AF Ilangovan, U Wojciak, JM Connolly, KM Clubb, RT TI NMR structure and functional studies of the Mu repressor DNA-binding domain SO BIOCHEMISTRY LA English DT Article ID INTEGRATION HOST FACTOR; SIDE-CHAIN RESONANCES; BACTERIOPHAGE-MU; LARGER PROTEINS; C-13 MAGNETIZATION; COUPLING-CONSTANTS; BACKBONE AMIDE; TRANSPOSITION; SPECTRA; SPECTROSCOPY AB The repressor protein of bacteriophage Mu establishes and maintains lysogeny by shutting down transposition functions needed for phage DNA replication. It interacts with several repeated DNA sequences within the early operator, preventing transcription from two divergent promoters. It also directly represses transposition by competing with the MuA transposase for an internal activation sequence (IAS) that is coincident with the operator and required for efficient transposition. The transposase and repressor proteins compete for the operator/IAS region using homologous DNA-binding domains located at their amino termini. Here we present the solution structure of the amino-terminal DNA-binding domain from the repressor protein determined by heteronuclear multidimensional nuclear magnetic resonance spectroscopy. The structure of the repressor DNA-binding domain provides insights into the molecular basis of several temperature sensitive mutations and, in combination with complementary experiments using flourescence anisotropy, surface plasmon resonance, and circular dichroism, defines the structural and biochemical differences between the transposase and repressor DNA-binding modules. We find that the repressor and enhancer domains possess similar three-dimensional structures, thermostabilities, and intrinsic affinities for DNA, This latter result suggests that the higher affinity of the full-length repressor relative to that of the MuA transposase protein originates from cooperative interactions between repressor protomers and not from intrinsic differences in their DNA-binding domains. In addition, we present the results of nucleotide and amino acid mutagenesis which delimits the minimal repressor DNA-binding module and coarsely defines the nucleotide dependence of repressor binding. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, DOE, Lab Struct Biol & Genet, Los Angeles, CA 90095 USA. RP Clubb, RT (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 405 Hilgard Ave, Los Angeles, CA 90095 USA. EM rclubb@mbi.ucla.edu NR 48 TC 20 Z9 20 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 JUN 29 PY 1999 VL 38 IS 26 BP 8367 EP 8376 DI 10.1021/bi990530b PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 213FW UT WOS:000081262900019 PM 10387082 ER PT J AU Adroja, DT Rainford, BD Malik, SK Takeya, H Gschneidner, KA Pecharsky, VK AF Adroja, DT Rainford, BD Malik, SK Takeya, H Gschneidner, KA Pecharsky, VK TI Neutron scattering studies on CeRhSb and PrTSb (T=Rh and Pd) compounds SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE Kondo insulator; crystal field excitations; neutron scattering study; CeRhSb; PrPdSb; PrRhSb ID ANTIFERROMAGNETIC CORRELATIONS; MAGNETIC-SUSCEPTIBILITY; TRANSPORT-PROPERTIES; HEAT-CAPACITY; CENISN; BEHAVIOR; GAP AB Inelastic neutron scattering studies have been carried out on the Kondo insulator CeRhSb as well as on PrTSb (T=Rh and Pd) compounds. The low energy neutron scattering spectra of CeRhSb at 2 K show no clear evidence of a gap type excitation. The high energy inelastic spectra of CeRhSb show a broad excitation centered about 35 meV, which is a characteristic of a Ce-based valence fluctuating compound. Inelastic spectra of PrRhSb show a presence of broad crystal field (CF) excitations with over-all crystal field splitting of 25 meV. On the other hand well-defined crystal field excitations corresponding to the 4f(2) configuration of the Pr3+ ion have been observed in PrPdSb. The crystal field parameters have been estimated from an analysis of inelastic neutron scattering data of PrPdSb. Analysis shows that the ground state of the Pr3+ ion is a crystal field doubler in this compound. The heat capacity calculated from the CF parameters suggests that the observed peak at 8 K in the heat capacity of PrPdSb is due to the magnetic ordering. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Southampton, Dept Phys, Southampton SO17 1BJ, Hants, England. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Adroja, DT (reprint author), Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. NR 17 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD JUN 29 PY 1999 VL 288 IS 1-2 BP 7 EP 12 DI 10.1016/S0925-8388(99)00086-9 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 208TE UT WOS:000081007100002 ER PT J AU Subramania, G Constant, K Biswas, R Sigalas, MM Ho, KM AF Subramania, G Constant, K Biswas, R Sigalas, MM Ho, KM TI Optical photonic crystals fabricated from colloidal systems SO APPLIED PHYSICS LETTERS LA English DT Article AB Photonic crystals of close-packed arrays of air spheres in a dielectric background of titania have been fabricated with a ceramic technique. Unlike previous methods, ordering of the spheres and the formation of the titania network are performed simultaneously. The photonic crystals exhibit a reflectance peak and a uniform color at the position of the first stop band. The wavelength of the reflectance peak scales very well with the sphere size. (C) 1999 American Institute of Physics. [S0003-6951(99)04526-X]. C1 US DOE, Ames Lab, Microelect Res Ctr, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Subramania, G (reprint author), US DOE, Ames Lab, Microelect Res Ctr, Ames, IA 50011 USA. RI Constant, Kristen/C-3673-2014 OI Constant, Kristen/0000-0001-7138-9365 NR 15 TC 182 Z9 187 U1 2 U2 25 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 JUN 28 PY 1999 VL 74 IS 26 BP 3933 EP 3935 DI 10.1063/1.124228 PG 3 WC Physics, Applied SC Physics GA 208MB UT WOS:000080994200005 ER PT J AU Kirtley, JR Tsuei, CC Moler, KA Kogan, VG Clem, JR Turberfield, AJ AF Kirtley, JR Tsuei, CC Moler, KA Kogan, VG Clem, JR Turberfield, AJ TI Variable sample temperature scanning superconducting quantum interference device microscope SO APPLIED PHYSICS LETTERS LA English DT Article ID HALL-PROBE MICROSCOPY; MAGNETIC FORCE MICROSCOPY; PENETRATION DEPTH; THIN-FILMS; VORTEX; YBA2CU3O7-DELTA; WAVE AB We demonstrate a design for a scanning superconducting quantum interference device (SQUID) microscope in which the sample temperature can be varied over a large range. In this design, both sample and SQUID are in the same vacuum space, separated by a few microns. By firmly anchoring the SQUID to a low-temperature bath, the sample temperature can be changed while the SQUID remains superconducting. This allows magnetic imaging at varying sample temperatures with micron-scale spatial resolution and the sensitivity of a low-T-c SQUID. We demonstrate this approach by imaging the temperature dependence of Abrikosov vortices in thin films of the high-temperature superconductor YBa2Cu3O7-delta. We extract the in-plane penetration depth lambda(ab)(T) in our samples from these measurements. (C) 1999 American Institute of Physics. [S0003-6951(99)04026-7]. C1 IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys, Ames, IA 50011 USA. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. RP Kirtley, JR (reprint author), IBM Corp, Thomas J Watson Res Ctr, POB 218, Yorktown Heights, NY 10598 USA. RI Moler, Kathryn/F-2541-2011 NR 21 TC 39 Z9 39 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 28 PY 1999 VL 74 IS 26 BP 4011 EP 4013 DI 10.1063/1.123244 PG 3 WC Physics, Applied SC Physics GA 208MB UT WOS:000080994200031 ER PT J AU Trajmar, S Kanik, I Khakoo, MA LeClair, LR Bray, I Fursa, D Csanak, G AF Trajmar, S Kanik, I Khakoo, MA LeClair, LR Bray, I Fursa, D Csanak, G TI Elastic electron scattering by laser-excited Ba-138(...6s6p P-1(1)) atoms SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID TRANSITION-PROBABILITIES; NEUTRAL BARIUM; CROSS-SECTIONS; SODIUM ATOMS; EXCITATION; IMPACT; ALIGNMENT; PARAMETERS; BA; ORIENTATION AB The results of a joint experimental and theoretical study concerning elastic electron scattering by laser-excited Ba-138(...6s6p P-1(1)) atoms are described. These studies demonstrate several important aspects of elastic electron collisions with coherently excited atoms, and are the first such studies. From the measurements, collision and coherence parameters, as well as cross sections associated with an atomic ensemble prepared with an arbitrary in-plane laser geometry and linear polarization (with respect to the collision frame), or equivalently with any magnetic sublevel superposition, have been obtained at 20 eV impact energy and at 10 degrees, 15 degrees and 20 degrees scattering angles. The convergent close-coupling (CCC) method was used within the non-relativistic LS-coupling framework to calculate the magnetic sublevel scattering amplitudes. From these amplitudes all the parameters and cross sections at 20 eV impact energy were extracted in the full angular range in 1 degrees steps. The experimental and theoretical results were found to be in good agreement, indicating that the CCC method can be reliably applied to elastic scattering by Ba-138(...6s6p P-1(1)) atoms, and possibly to other heavy elements when spin-orbit coupling effects are negligible. Small but significant asymmetry was observed in the cross sections for scattering to the left and to the right. It was also found that elastic electron scattering by the initially isotropic atomic ensemble resulted in the creation of significant alignment. As a byproduct of the present studies, elastic scattering cross sections for metastable Ba-138 atoms were also obtained. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91109 USA. Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. Flinders Univ S Australia, Elect Struct Mat Ctr, Adelaide, SA 5001, Australia. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Trajmar, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 49 TC 8 Z9 8 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 JUN 28 PY 1999 VL 32 IS 12 BP 2801 EP 2829 DI 10.1088/0953-4075/32/12/302 PG 29 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 214CK UT WOS:000081309900007 ER PT J AU Buffington, GD Madison, DH Peacher, JL Schultz, DR AF Buffington, GD Madison, DH Peacher, JL Schultz, DR TI Lattice, time-dependent approach for electron-hydrogen scattering SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID SPLINE COLLOCATION METHOD; IMPACT IONIZATION; INTERMEDIATE ENERGIES; 2ND-ORDER EXCHANGE; COUPLING METHODS; THRESHOLD AB A time-dependent approach for treating electron-hydrogen scattering is reported that utilizes a fully correlated two-electron wavefunction represented on a three-dimensional lattice using the basis-spline collocation method. The lattice, time-dependent approach obviates the need for consideration of the three-body Coulomb boundary conditions, avoids the use of severe approximations such as those of perturbation theory for slow collisions, and provides a relatively dense representation of the one- and two-electron continua. Probabilities for excitation and ionization are computed by projection onto lattice eigenstates of the H atom. Partial cross sections for excitation and ionization are obtained and compared with results of other theoretical methods for the S-1 and S-3 channels. C1 Ft Hays State Univ, Dept Phys, Hays, KS 67601 USA. Univ Missouri, Dept Phys, Rolla, MO 65409 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Buffington, GD (reprint author), Ft Hays State Univ, Dept Phys, Hays, KS 67601 USA. NR 33 TC 16 Z9 16 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 JUN 28 PY 1999 VL 32 IS 12 BP 2991 EP 3001 DI 10.1088/0953-4075/32/12/316 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 214CK UT WOS:000081309900021 ER PT J AU Roy, M Mitchell, JF Ramirez, AP Schiffer, P AF Roy, M Mitchell, JF Ramirez, AP Schiffer, P TI A study of the magnetic and electrical crossover region of La0.5 +/-delta Ca0.5 -/+delta MnO3 SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; DOUBLE EXCHANGE; GIANT MAGNETORESISTANCE; POLARON FORMATION; DOPED LAMNO3; CHARGE; LA1-XCAXMNO3; FIELD; TRANSITION; PHASE AB The ground states of La1-xCaxMnO3 change from double-exchange-associated conducting ferromagnets at x < 0.50 to charge-ordered antiferromagnets at x > 0.50 even when x is varied only slightly around 0.50. We have performed a careful study of the electrical and magnetic properties of these materials for a range of samples with slightly varying calcium doping around x Et; 0.50. The natures of the ground state and the transition were found to be sensitive not only to the calcium doping but also to the actual Mn4+ content of these materials. The low-temperature resistivity of the x approximate to 0.50 materials below the charge-ordering temperature was found to drop with decreasing temperature in the presence of magnetic fields of even a few teslas or a slight Ca underdoping (x less than or similar to 0.50), revealing the presence of some free carriers even in the charge-ordered states. The data therefore demonstrate a coexistence of ferromagnetic conducting and antiferromagnetic charge-ordered phases in the perovskite manganites. We also observe field-induced 'annealing' in the charge-ordered state due to the partial delocalization of the carriers. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Roy, M (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RI Schiffer, Peter/F-3227-2011; OI Schiffer, Peter/0000-0002-6430-6549 NR 50 TC 32 Z9 32 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUN 28 PY 1999 VL 11 IS 25 BP 4843 EP 4859 DI 10.1088/0953-8984/11/25/305 PG 17 WC Physics, Condensed Matter SC Physics GA 214CF UT WOS:000081309500010 ER PT J AU Barbieri, R Hall, LJ Romanino, A AF Barbieri, R Hall, LJ Romanino, A TI Precise tests of a quark mass texture SO NUCLEAR PHYSICS B LA English DT Article DE flavour; symmetries; masses; mixings ID U(2) FLAVOR SYMMETRY; PREDICTIONS; MODEL AB The relations \V-ub/V-cb\ = (mu/mc)(1/2) and \V-td/Vts\ = (m(d)/m(s))(1/2) between the CKM matrix elements and the quark masses are shown to imply a remarkably precise determination of the CKM unitarity triangle or of the Wolfenstein parameters rho, eta consistent with the data so far, We view this as a clean test of a quark mass texture neatly arising from a hierarchical breaking of a U(2) flavour symmetry. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Scuola Normale Super Pisa, I-56126 Pisa, Italy. Ist Nazl Fis Nucl, Sez Pisa, I-56126 Pisa, Italy. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Oxford, Dept Phys, Oxford OX1 3NP, England. RP Barbieri, R (reprint author), Scuola Normale Super Pisa, I-56126 Pisa, Italy. RI Romanino, Andrea/I-3480-2012 OI Romanino, Andrea/0000-0002-5915-4747 NR 15 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD JUN 28 PY 1999 VL 551 IS 1-2 BP 93 EP 101 DI 10.1016/S0550-3213(99)00215-1 PG 9 WC Physics, Particles & Fields SC Physics GA 212LJ UT WOS:000081217900004 ER PT J AU Paz, JP Zurek, WH AF Paz, JP Zurek, WH TI Quantum limit of decoherence: Environment induced superselection of energy eigenstates SO PHYSICAL REVIEW LETTERS LA English DT Article ID COHERENT STATES; WAVE-FUNCTION; PREDICTABILITY; CLASSICALITY; EMERGENCE AB We investigate decoherence in the limit where the interaction with the environment is weak and the evolution is dominated by the self-Hamiltonian of the system. We show that in this case quantized eigenstates of energy emerge as pointer states selected through the predictability sieve. C1 Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis JJ Giambiagi, RA-1428 Buenos Aires, DF, Argentina. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Paz, JP (reprint author), Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis JJ Giambiagi, Pabellon 1,Ciudad Univ, RA-1428 Buenos Aires, DF, Argentina. RI Paz, Juan/C-5947-2008 NR 29 TC 111 Z9 112 U1 1 U2 14 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5181 EP 5185 DI 10.1103/PhysRevLett.82.5181 PG 5 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700001 ER PT J AU Futagami, T Fukuda, Y Hayakawa, T Inoue, K Ishihara, K Ishino, H 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 Kanzaki, J Kobayashi, T Nakamura, K Nishikawa, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT 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 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 Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D George, JS Stachyra, AL Wai, LL Wilkes, RJ Young, KK AF Futagami, T Fukuda, Y Hayakawa, T Inoue, K Ishihara, K Ishino, H 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 Kanzaki, J Kobayashi, T Nakamura, K Nishikawa, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT 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 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 Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D George, JS Stachyra, AL Wai, LL Wilkes, RJ Young, KK CA Super Kamiokande Collaboration TI Observation of the east-west anisotropy of the atmospheric neutrino flux SO PHYSICAL REVIEW LETTERS LA English DT Article AB The east-west anisotropy. caused by the deflection of primary cosmic rays in the Earth's magnetic field, is observed for the first time in the flux of atmospheric neutrinos. Using a 45 kt yr exposure of the Super-Kamiokande detector, 552 e-like and 633 mu-like horizontally going events are selected in the momentum range between 400 and 3000 MeV/c. The azimuthal distributions of e-like and mu-like events agree with the expectation from atmospheric neutrino flux calculations, verifying that the flux of atmospheric neutrinos in the GeV energy range is reasonably well modeled by calculations that account for the geomagnetic field. C1 Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. Univ Tokyo, Inst Cosm Ray Res, 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, Ibaraki, Osaka 3050801, Japan. Kobe Univ, Dept Phys, Kobe, Hyogo 6578501, 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. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Niigata Univ, Dept Phys, Niigata 9502181, Japan. Osaka Univ, Dept Phys, 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, Kanagawa 2591292, Japan. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Futagami, T (reprint author), Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. RI 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; Obayashi, Yoshihisa/A-4472-2011 OI Sakurai, Nobuyuki/0000-0002-1002-217X; Ishino, Hirokazu/0000-0002-8623-4080; Koshio, Yusuke/0000-0003-0437-8505; NR 14 TC 87 Z9 87 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 JUN 28 PY 1999 VL 82 IS 26 BP 5194 EP 5197 DI 10.1103/PhysRevLett.82.5194 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700004 ER PT J AU Felix, J Avilez, C Christian, DC Church, MD Forbush, M Gottschalk, EE Gutierrez, G Hartouni, EP Holmes, SD Huson, FR Jensen, DA Knapp, BC Kreisler, MN Moreno, G Uribe, J Stern, BJ Wang, MHLS Wehmann, A Wiencke, LR White, JT AF Felix, J Avilez, C Christian, DC Church, MD Forbush, M Gottschalk, EE Gutierrez, G Hartouni, EP Holmes, SD Huson, FR Jensen, DA Knapp, BC Kreisler, MN Moreno, G Uribe, J Stern, BJ Wang, MHLS Wehmann, A Wiencke, LR White, JT TI Study of Lambda(0) polarization in four different exclusive pp reactions at 27.5 GeV/c SO PHYSICAL REVIEW LETTERS LA English DT Article ID PROTON-PROTON INTERACTIONS; HYPERON POLARIZATION; MAGNETIC-MOMENT; INCLUSIVE PRODUCTION; QUARK POLARIZATION; 300-GEV PROTONS; 400-GEV PROTONS; 12-GEV PROTONS; HIGH-ENERGIES; COLLISIONS AB We have measured the x(F) and P-T dependence of the polarization of Lambda(0) hyperons produced in exclusive final states pp --> p Lambda 0K(+) pi(+)pi(-), pp --> p Lambda(0)K(+)pi(+)pi(-)pi(+)pi(-), pp --> p Lambda(0)K(+)pi(+)pi(-)pi(+)pi(-)pi(+)pi(-), and pp --> p Lambda(0)K(+)pi(+)pi(-)pi(+)pi(-)pi(+)pi(-)pi(+)pi(-) at 27.5 GeV/c. We present an empirical parametrization for Lambda(0) polarization as a function of x(F) and P-T: P = (-0.443 +/- 0.037)x(F)P(T) for -1 less than or equal to x(F) less than or equal to 1 and 0 less than or equal to P-T less than or equal to 1.8 GeV/c. This parametrization is independent of the final state and provides a good description of the data. We note that the mechanism responsible for Lambda(0) polarization appears to be independent of the production mechanism. C1 Univ Guanajuato, Leon, Guanajuato, Mexico. Univ Massachusetts, Amherst, MA 01003 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Columbia Univ, Nevis Labs, Irvington, NY 10533 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RP Felix, J (reprint author), Univ Guanajuato, Leon, Guanajuato, Mexico. NR 51 TC 19 Z9 19 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 JUN 28 PY 1999 VL 82 IS 26 BP 5213 EP 5216 DI 10.1103/PhysRevLett.82.5213 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700009 ER PT J AU Devlin, M Afanasjev, AV Clark, RM LaFosse, DR Lee, IY Lerma, F Macchiavelli, AO MacLeod, RW Ragnarsson, I Ring, P Rudolph, D Sarantites, DG Thirolf, PG AF Devlin, M Afanasjev, AV Clark, RM LaFosse, DR Lee, IY Lerma, F Macchiavelli, AO MacLeod, RW Ragnarsson, I Ring, P Rudolph, D Sarantites, DG Thirolf, PG TI Superdeformation in Zn-68: Evidence for a new, neutron-rich island of superdeformation in A similar to 70 nuclei SO PHYSICAL REVIEW LETTERS LA English DT Article ID MEAN-FIELD THEORY; QUADRUPOLE-MOMENT MEASUREMENT; MASS REGION; ROTATIONAL BANDS; HIGH-SPIN; ZR-84 AB A superdeformed rotational structure is reported in the stable nucleus Zn-68. It has a transition quadrupole moment (Q(t)) of 2.5(-0.4)(+0.7) e b (beta(2) approximate to 0.4), as measured by the residual Doppler shift method. Theoretical calculations suggest that two different configurations are possible candidates for this band. One is built without h(11/2) neutrons, as seen in superdeformed bands in the A similar to 60 region, while the other involves one h(11/2) neutron in analogy with superdeformed bands in the A similar to 80 region. The second of these candidate configurations is preferred, thus establishing a new, neutron-rich (relative to the line of beta stability) region of superdeformation with Z similar to 30 and N similar to 38. C1 Washington Univ, Dept Chem, St Louis, MO 63130 USA. Lund Inst Technol, Dept Math Phys, S-22100 Lund, Sweden. 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. Univ Munich, Sekt Phys, D-85748 Garching, Germany. RP Devlin, M (reprint author), Washington Univ, Dept Chem, St Louis, MO 63130 USA. RI Rudolph, Dirk/D-4259-2009; Devlin, Matthew/B-5089-2013; Ring, Peter/O-1638-2015 OI Rudolph, Dirk/0000-0003-1199-3055; Devlin, Matthew/0000-0002-6948-2154; NR 26 TC 22 Z9 23 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 JUN 28 PY 1999 VL 82 IS 26 BP 5217 EP 5220 DI 10.1103/PhysRevLett.82.5217 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700010 ER PT J AU Catravas, P Leemans, WP Wurtele, JS Zolotorev, MS Babzien, M Ben-Zvi, I Segalov, Z Wang, XJ Yakimenko, V AF Catravas, P Leemans, WP Wurtele, JS Zolotorev, MS Babzien, M Ben-Zvi, I Segalov, Z Wang, XJ Yakimenko, V TI Measurement of electron-beam bunch length and emittance using shot-noise-driven fluctuations in incoherent radiation SO PHYSICAL REVIEW LETTERS LA English DT Article ID INJECTION; PULSES; RF AB Longitudinal and transverse phase space information has been obtained from a statistical analysis of fluctuations in the radiation spectrum of an electron bunch. Uncorrelated shot noise fluctuations in longitudinal beam density result in incoherent radiation with a spectrum that consists of spikes, with width inversely proportional to the bunch length. Measurements were performed at lambda = 620 nm on a 1-5 ps long, 44 MeV bunch propagating through a wiggler. Bunch length and emittance obtained with this single shot technique agree with independent measurements. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. Brookhaven Natl Lab, Accelerator Test Facil, Upton, NY 11973 USA. RP Catravas, P (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Beam Phys, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI wurtele, Jonathan/J-6278-2016 OI wurtele, Jonathan/0000-0001-8401-0297 NR 21 TC 30 Z9 30 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 JUN 28 PY 1999 VL 82 IS 26 BP 5261 EP 5264 DI 10.1103/PhysRevLett.82.5261 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700021 ER PT J AU Bogicevic, A AF Bogicevic, A TI Metal-on-metal bonding and rebonding revisited SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE-DIFFUSION; MOLECULAR-DYNAMICS; EXCHANGE; PT(001); ADATOM; SOLIDS AB Density-functional calculations for a wide variety of metals show that, contrary to rebonding theory, ad-dimers do not have notably longer surface bonds than adatoms, do not reside farther above the surface, and do not meet the rebonding arguments for augmented mobility. Rebonding contributes to destabilize ad-dimers, but does not explain inherently weak ad-dimer bonds. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Surface & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 21 Z9 21 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5301 EP 5304 DI 10.1103/PhysRevLett.82.5301 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700031 ER PT J AU Grigorov, IL Fitzsimmons, MR Siu, IL Walker, JC AF Grigorov, IL Fitzsimmons, MR Siu, IL Walker, JC TI Observation and analysis of multidomain epitaxy of alpha-Mn on MgO(111) SO PHYSICAL REVIEW LETTERS LA English DT Article ID THIN-FILMS; FE FILMS; GROWTH; SUPERLATTICES; SURFACE; PD(111); CU(111); PHASE AB Thin films of alpha-Mn were epitaxially grown on MgO(111) single-crystalline substrates at elevated temperatures in order to suppress the growth of metastable Mn phases previously reported. The alpha-Mn films were observed to have (110) texture, consistent with bcc (110) growth in Kurdjumov-Sachs orientation on the fee (111) substrate surface, with additional twinning. The structural features observed for alpha-Mn(110) resemble those of metastable "expanded" Mn, indicating a possible connection between the two phases. C1 Teledyne Elect Technol, Los Angeles, CA 90066 USA. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Grigorov, IL (reprint author), Teledyne Elect Technol, Los Angeles, CA 90066 USA. RI Lujan Center, LANL/G-4896-2012 NR 29 TC 18 Z9 18 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5309 EP 5312 DI 10.1103/PhysRevLett.82.5309 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700033 ER PT J AU Ortiz, G Harris, M Ballone, P AF Ortiz, G Harris, M Ballone, P TI Zero temperature phases of the electron gas SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM MONTE-CARLO; CORRELATION-ENERGY; WAVE-FUNCTIONS AB The stability of different phases of the three-dimensional nonrelativistic electron gas is analyzed using stochastic methods. With decreasing density, we observe a continuous transition from the paramagnetic to the ferromagnetic fluid, with an intermediate stability range (20 +/- 5 less than or equal to r(s) less than or equal to 40 +/- 5) for the partially spin-polarized liquid. The freezing transition into a ferromagnetic Wigner crystal occurs at r(s) = 65 +/- 10. We discuss the relative stability of different magnetic structures in the solid phase. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Univ Messina, Ist Nazl Fis Mat, I-98166 Messina, Italy. RP Ortiz, G (reprint author), Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 15 TC 146 Z9 146 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5317 EP 5320 DI 10.1103/PhysRevLett.82.5317 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700035 ER PT J AU Ahn, JS Bak, J Choi, HS Noh, TW Han, JE Bang, Y Cho, JH Jia, QX AF Ahn, JS Bak, J Choi, HS Noh, TW Han, JE Bang, Y Cho, JH Jia, QX TI Spectral evolution in (Ca,Sr)RuO3 near the Mott-Hubbard Transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID EPITAXIAL THIN-FILMS; OPTICAL CONDUCTIVITY; METAL; SPECTROSCOPY; INSULATOR; CRYSTAL; OXIDES; ENERGY; GAP; CA1-XSRXVO3 AB We investigated optical properties of (Ca,Sr)RuO3 films on the borderline of a metal-insulator transition. Our results show all of the predicted characteristics for a metallic Mott-Hubbard system, including (i) a mass enhancement in de limit, (ii) a U/2 excitation, and (iii) a U excitation. Also, self-consistency is exploited within the Gutzwiller-Brinkman-Rice picture for the Mott transition. Our finding displays that electron correlation should be important even in 4d materials. However, low frequency behaviors of electrodynamic quantities suggest extra scattering mechanisms in addition to the Mott-Hubbard correlation. C1 Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Chonnam Natl Univ, Dept Phys, Kwangju 500757, South Korea. Pusan Natl Univ, RCDAMP, Pusan 609735, South Korea. Pusan Natl Univ, Dept Phys, Pusan 609735, South Korea. Los Alamos Natl Lab, Supercond Technol Ctr, Los Alamos, NM 87545 USA. RP Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. RI Han, Jong/E-7311-2011; Noh, Tae Won /K-9405-2013; Jia, Q. X./C-5194-2008 OI Han, Jong/0000-0002-5518-2986; NR 29 TC 57 Z9 57 U1 0 U2 7 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 JUN 28 PY 1999 VL 82 IS 26 BP 5321 EP 5324 DI 10.1103/PhysRevLett.82.5321 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700036 ER PT J AU Balatsky, AV Bourges, P AF Balatsky, AV Bourges, P TI Linear dependence of peak width in chi(q, omega) vs T-c for YBa2Cu3O6+x superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID INELASTIC-NEUTRON-SCATTERING; SPIN DYNAMICS; MAGNETIC DYNAMICS; UNDERDOPED YBA2CU3O7-X; NORMAL-STATE; SYSTEM YBA2CU3O6+X; GAP; FLUCTUATIONS; BI2SR2CACU2O8+DELTA; PSEUDOGAP AB It is shown that the momentum space width of the peak in the spin susceptibility, Im chi(q,omega), is linearly proportional to the superconducting T-c: T-c = (h) over bar upsilon*Delta q with (h) over bar upsilon* similar or equal to 35 meV Angstrom. This relation is similar to the linear relation between incommensurate peak splitting and T-c in LaSrCuO superconductors, as first proposed by Yamada et al. [Phys. Rev. B 57, 6165 (1998)]. The velocity (h) over bar upsilon* is smaller than Fermi velocity or the spin-wave velocity of the parent compound and remains the same for a wide doping range. This result points towards strong similarities in magnetic state of YBa2Cu3O6+x and LaSrCuO. C1 Los Alamos Natl Lab, Div T, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, MST Div, Los Alamos, NM 87545 USA. Ctr Etud Saclay, Leon Brillouin Lab, F-91191 Gif Sur Yvette, France. RP Balatsky, AV (reprint author), Los Alamos Natl Lab, Div T, POB 1663, Los Alamos, NM 87545 USA. NR 41 TC 56 Z9 56 U1 0 U2 2 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 JUN 28 PY 1999 VL 82 IS 26 BP 5337 EP 5340 DI 10.1103/PhysRevLett.82.5337 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700040 ER PT J AU Latyshev, YI Yamashita, T Bulaevskii, LN Graf, MJ Balatsky, AV Maley, MP AF Latyshev, YI Yamashita, T Bulaevskii, LN Graf, MJ Balatsky, AV Maley, MP TI Interlayer transport of quasiparticles and Cooper pairs in Bi2Sr2CaCu2O8+delta superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID INTRINSIC JOSEPHSON-JUNCTIONS; D-WAVE SUPERCONDUCTORS; SINGLE-CRYSTALS; CONDUCTIVITY; GAP; DEPENDENCE; WHISKERS AB We study the c-axis transport of stacked, intrinsic junctions in Bi2Sr2CaCu2O8+delta single crystals, fabricated by the double-sided ion beam processing technique from single crystal whiskers. Measurements of the I-V characteristics of these samples allow us to obtain the temperature and voltage dependence of the quasiparticle c-axis conductivity in the superconducting state, the Josephson critical current, and the superconducting gap. We show that the BCS d-wave model in the clean limit for resonant impurity scattering, with a significant contribution from coherent interlayer tunneling, describes satisfactorily the low temperature and low energy c-axis transport of both quasiparticles and Cooper pairs. C1 Tohoku Univ, Elect Commun Res Inst, Aoba Ku, Sendai, Miyagi 9808577, Japan. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, Los Alamos, NM 87545 USA. Russian Acad Sci, Inst Radio Engn & Elect, Moscow 103907, Russia. RP Latyshev, YI (reprint author), Tohoku Univ, Elect Commun Res Inst, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan. NR 21 TC 109 Z9 109 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 JUN 28 PY 1999 VL 82 IS 26 BP 5345 EP 5348 DI 10.1103/PhysRevLett.82.5345 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700042 ER PT J AU Rubhausen, M Hammerstein, OA Bock, A Merkt, U Rieck, CT Guptasarma, P Hinks, DG Klein, MV AF Rubhausen, M Hammerstein, OA Bock, A Merkt, U Rieck, CT Guptasarma, P Hinks, DG Klein, MV TI Doping dependence of the electronic interactions in Bi-2212 cuprate superconductors: Doped antiferromagnets or antiferromagnetic Fermi liquids? SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAMAN-SCATTERING; ENERGY EXCITATIONS; LIGHT-SCATTERING; SINGLE-CRYSTALS; SPIN; GAP; BI2SR2CACU2O8+DELTA; FLUCTUATIONS; RESONANCE AB Electron-electron interactions in overdoped Bi-2212 are studied by inelastic light scattering. The optimally to slightly overdoped compounds exhibit two-magnon excitations with a dependence on the incident photon energy typical for doped antiferromagnets. For more overdoped samples, no two-magnon excitation is visible, indicating an antiferromagnetic correlation below twice the lattice parameter. In the same samples, the gap excitation shows a resonance similar to the two-magnon excitation. We interpret our results as a development towards a correlated Fermi liquid when the doping is increased. C1 Univ Hamburg, Inst Angew Phys, D-20355 Hamburg, Germany. Univ Hamburg, Zentrum Mikrostrukturforsch, D-20355 Hamburg, Germany. Univ Hamburg, Inst Theoret Phys 1, D-20355 Hamburg, Germany. Argonne Natl Lab, MSD STCS, Argonne, IL 60439 USA. Univ Illinois, STCS, Urbana, IL 61801 USA. RP Rubhausen, M (reprint author), Loomis, 1110 W Green St, Urbana, IL 61801 USA. NR 29 TC 27 Z9 27 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5349 EP 5352 DI 10.1103/PhysRevLett.82.5349 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700043 ER PT J AU Somaroo, S Tseng, CH Havel, TF Laflamme, R Cory, DG AF Somaroo, S Tseng, CH Havel, TF Laflamme, R Cory, DG TI Quantum simulations on a quantum computer SO PHYSICAL REVIEW LETTERS LA English DT Article ID ERROR-CORRECTION; COMPUTATION; UNIVERSAL; GATES AB We present a general scheme for performing a simulation of the dynamics of one quantum system using another. This scheme is used to experimentally simulate the dynamics of truncated quantum harmonic and anharmonic oscillators using nuclear magnetic resonance. We believe this to be the first explicit physical realization of such a simulation. C1 MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. Harvard Univ, Sch Med, BCMP, Boston, MA 02115 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87455 USA. RP Cory, DG (reprint author), MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. NR 17 TC 106 Z9 110 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 JUN 28 PY 1999 VL 82 IS 26 BP 5381 EP 5384 DI 10.1103/PhysRevLett.82.5381 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700051 ER PT J AU Park, W Fredrickson, ED AF Park, W Fredrickson, ED TI beta limit disruptions in tokamaks - Comment SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Park, W (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 4 TC 3 Z9 3 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5413 EP 5413 DI 10.1103/PhysRevLett.82.5413 PG 1 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700059 ER PT J AU Krumke, SO Noltemeier, H Wirth, HC Marathe, MV Ravi, R Ravi, SS Sundaram, R AF Krumke, SO Noltemeier, H Wirth, HC Marathe, MV Ravi, R Ravi, SS Sundaram, R TI Improving spanning trees by upgrading nodes SO THEORETICAL COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 24th International Colloquium on Algorithm, Languages and Programming (ICALP 97) CY JUL 07-11, 1997 CL BOLOGNA, ITALY SP UN, Educ Sci & Cultural Org, Venice Off, Italian Natl Council Res, CNR, GNIM, CNR, IEI, Univ Bologna, Univ Pisa, Univ Roma La Sapienza, Regione Emilia Romagna, TELECOM Italia, USAF, European Off Aerosp Res & Dev DE NP-hardness; approximation algorithms; network design; spanning tree ID REDUCTION; GRAPHS AB We study bottleneck constrained network upgrading problems. We are given an edge weighted graph G = (V, E) where node upsilon is an element of V can be upgraded at a cost of c(upsilon), This upgrade reduces the delay of each link emanating from v. The goal is to find a minimum cost set of nodes to be upgraded so that the resulting network has good performance. The performance is measured by the bottleneck weight of a minimum spanning tree. We give a polynomial time approximation algorithm with logarithmic performance guarantee, which is tight within a small constant factor as shown by our hardness results. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Konrad Zuse Zentrum Informat Tech Berlin ZIB, D-14195 Berlin, Germany. Univ Wurzburg, Dept Comp Sci, D-97074 Wurzburg, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Carnegie Mellon Univ, GSIA, Pittsburgh, PA 15213 USA. SUNY Albany, Dept Comp Sci, Albany, NY 12222 USA. MIT, Cambridge, MA 02139 USA. RP Krumke, SO (reprint author), Konrad Zuse Zentrum Informat Tech Berlin ZIB, Takustr 7, D-14195 Berlin, Germany. NR 16 TC 9 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3975 J9 THEOR COMPUT SCI JI Theor. Comput. Sci. PD JUN 28 PY 1999 VL 221 IS 1-2 BP 139 EP 155 DI 10.1016/S0304-3975(99)00030-4 PG 17 WC Computer Science, Theory & Methods SC Computer Science GA 214LA UT WOS:000081328400008 ER PT J AU Hypes, P AF Hypes, P TI Uranium in war SO NEW SCIENTIST LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hypes, P (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 USA SN 0262-4079 J9 NEW SCI JI New Sci. PD JUN 26 PY 1999 VL 162 IS 2192 BP 58 EP 58 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 211BG UT WOS:000081139600039 ER PT J AU Pruski, M Bailly, A Lang, DP Amoureux, JP Fernandez, C AF Pruski, M Bailly, A Lang, DP Amoureux, JP Fernandez, C TI Studies of heteronuclear dipolar interactions between spin-1/2 and quadrupolar nuclei by using REDOR during multiple quantum evolution SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ANGLE-SPINNING NMR; ECHO DOUBLE-RESONANCE; CROSS-POLARIZATION; ROTATIONAL-ECHO; MAS; SPECTRA; SOLIDS; SPINS; ROTOR AB A new technique for measurements of dipolar interactions in rotating solids is presented that combines the capabilities of multiple quantum magic angle spinning (MQMAS) with the rotational echo double resonance (REDOR). It employs the dipolar recoupling between spin-1/2 (I) and quadrupolar (S) nuclei by applying a series of pi pulses to the I spins. In contrast to the previously reported MQ-REDOR method, the recoupling sequence is applied during the triple quantum, rather than single quantum evolution. As the dipolar effect is enhanced by the MQ coherence order, this new technique exhibits improved sensitivity toward weak dipolar interactions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Lille, CNRS URA 801, Lab Dynam & Struct Mat Mol, F-59655 Villeneuve Dascq, France. Univ Caen, ISMRA, CNRS UMR 6506, Catalyse & Spectrochim Lab, F-14050 Caen, France. RP Pruski, M (reprint author), Iowa State Univ, Ames Lab, 230 Spedding Hall, Ames, IA 50011 USA. RI fernandez, christian/C-3158-2008 OI fernandez, christian/0000-0002-5476-3148 NR 25 TC 31 Z9 31 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 25 PY 1999 VL 307 IS 1-2 BP 35 EP 40 DI 10.1016/S0009-2614(99)00490-X PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 210GY UT WOS:000081097800006 ER PT J AU Holmes, RL Dimonte, G Fryxell, B Gittings, ML Grove, JW Schneider, M Sharp, DH Velikovich, AL Weaver, RP Zhang, Q AF Holmes, RL Dimonte, G Fryxell, B Gittings, ML Grove, JW Schneider, M Sharp, DH Velikovich, AL Weaver, RP Zhang, Q TI Richtmyer-Meshkov instability growth: experiment, simulation and theory SO JOURNAL OF FLUID MECHANICS LA English DT Article ID RAYLEIGH-TAYLOR; NUMERICAL-SIMULATION; NONLINEAR-THEORY; FRONT TRACKING; GAS-DYNAMICS; NOVA LASER; SHOCK-WAVE; DRIVEN; INTERFACE; FLOW AB Richtmyer-Meshkov instability is investigated for negative Atwood number and two-dimensional sinusoidal perturbations by comparing experiments, numerical simulations and analytic theories. The experiments were conducted on the NOVA laser with strong radiatively driven shocks with Mach numbers greater than 10. Three different hydrodynamics codes (RAGE, PROMETHEUS and FroriTier) reproduce the amplitude evolution and the gross features in the experiment while the fine-scale features differ in the different numerical techniques. Linearized theories correctly calculate the growth rates at small amplitude and early time, but fail at large amplitude and late time. A nonlinear theory using asymptotic matching between the linear theory and a potential flow model shows much better agreement with the late-time and large-amplitude growth rates found in the experiments and simulations. We vary the incident shock strength and initial perturbation amplitude to study the behaviour of the simulations and theory and to study the effects of compression and nonlinearity. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Drexel Univ, Dept Phys & Atmospher Sci, Philadelphia, PA 19104 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. SUNY Stony Brook, Dept Appl Math & Stat, Stony Brook, NY 11794 USA. Berkeley Res Associates, Springfield, VA USA. RP Holmes, RL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Velikovich, Alexander/B-1113-2009; OI ZHANG, Qiang /0000-0002-8659-5396 NR 49 TC 138 Z9 142 U1 9 U2 27 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUN 25 PY 1999 VL 389 BP 55 EP 79 DI 10.1017/S0022112099004838 PG 25 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 219FH UT WOS:000081596900003 ER PT J AU Gonzalez, RL Tinoco, I AF Gonzalez, RL Tinoco, I TI Solution structure and thermodynamics of a divalent metal ion binding site in an RNA pseudoknot SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA structure and thermodynamics; NMR; metal binding; pseudoknot; frameshifting ID MAMMARY-TUMOR VIRUS; RIBOSOMAL FRAMESHIFT SIGNAL; DOUBLE-STRANDED-RNA; CRYSTAL-STRUCTURE; MESSENGER-RNA; SIMIAN RETROVIRUS-1; HAMMERHEAD RIBOZYME; NMR STRUCTURE; MAJOR GROOVE; STABILITY AB Identification and characterization of a metal ion binding site in an RNA pseudoknot was accomplished using cobalt (III) hexammine, Co(NH3)(6)(3+), as a probe for magnesium (II) hexahydrate, Mg(H6O)(6)(2+), in nuclear magnetic resonance (NMR) structural studies. The pseudoknot causes efficient -1 ribosomal frameshifting in mouse mammary tumor virus. Divalent metal ions, such as Mg2+, are critical for RNA structure and function; Mg2+ preferentially stabilizes the pseudoknot relative to its constituent hairpins. The use of Co(NH3)(6)(3+) as a substitute for Mg2+ was investigated by ultraviolet absorbance melting curves, NMR titrations of the imino protons, and analysis of NMR spectra in the presence of Mg2+ or Co (NH3)(6)(3+) The structure of the pseudoknot-Co(NH3)(6)(3+) complex reveals an ion-binding pocket formed by a short, two-nucleotide loop and the major groove of a stem. Co(NH3)(6)(3+) stabilizes the sharp loop-to-stem turn and reduces the electrostatic repulsion of the phosphates in three proximal strands. Hydrogen bonds are identified between the Co(NH3)(6)(3+) protons and non-bridging phosphate oxygen atoms, 2' hydroxyl groups, and nitrogen and oxygen accepters on the bases. The binding site is significantly different from that previously characterized in the major groove surface of tandem G.U base-pairs, but is similar to those observed in crystal structures of a fragment of the 5 S rRNA and the P5c helix of the Tetrahymena thermophila group I intron. Changes in chemical shifts occurred at the same pseudoknot protons on addition of Mg2+ as on addition of Co(NH3)(6)(3+), indicating that both ions bind at the same site. Ion binding dissociation constants of approximately 0.6 mM and 5 mM (in 200 mM Na+ and a temperature of 15 degrees C) were obtained for Co(NH3)(6)(3+) and Mg2+, respectively, from the change in chemical shift as a function of metal ion concentration. An extensive array of non-sequence-specific hydrogen bond accepters coupled with conserved structural elements within the binding pocket suggest a general mode of divalent metal ion stabilization of this type of frameshifter pseudoknot. These results provide new thermodynamic and structural insights into the role divalent metal ions play in stabilizing RNA tertiary structural motifs such as pseudoknots. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Phys Biosci Div, Dept Biol Struct, Berkeley, CA 94720 USA. RP Tinoco, I (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM 10840] NR 61 TC 80 Z9 81 U1 0 U2 9 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUN 25 PY 1999 VL 289 IS 5 BP 1267 EP 1282 DI 10.1006/jmbi.1999.2841 PG 16 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 212NM UT WOS:000081223100010 PM 10373367 ER PT J AU Kuchumov, AR Taveau, JC Lamy, JN Wall, JS Weber, RE Vinogradov, SN AF Kuchumov, AR Taveau, JC Lamy, JN Wall, JS Weber, RE Vinogradov, SN TI The role of linkers in the reassembly of the 3.6 MDa hexagonal bilayer hemoglobin from Lumbricus terrestris SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE hemoglobin; Lumbricus terrestris; hexagonal bilayer; kinetics of reassembly; dodecamer subunits ID GIANT EXTRACELLULAR HEMOGLOBIN; MASS-SPECTROMETRIC COMPOSITION; 3-DIMENSIONAL RECONSTRUCTION; QUATERNARY STRUCTURE; CRYOELECTRON MICROSCOPY; MACROBDELLA-DECORA; FAMILIAL HYPERCHOLESTEROLEMIA; DODECAMER SUBUNIT; MOLECULAR-MASS; GLOBIN CHAINS AB The extent and kinetics of reassembly of the four groups of linkers L1-L4 with 213 kDa subassemblies of twelve globin chains D, (bac)(3)(d)(3), isolated from the similar to 3.6 MDa hexagonal bilayer (HBL) hemoglobin (Hb) of Lumbricus terrestris, was investigated using gel filtration. The reassembled HBL's were characterized by scanning transmission electron microscopic (STEM) mass mapping and their subunit content determined by reversed-phase chromatography. Ln reassembly by method (A), the linkers isolated by RP-HPLC at pH similar to 2.2 were added to D at neutral pH; in method (B), the linkers were renatured at neutral pH and then added to D. With method (A) the percentage of HBL reassembly varied from greater than or equal to 13 % in the absence of Ca(II) to less than or equal to 75 % in 1-10 mM Ca(II). Reassembly to HBL structures whose linker contents, STEM images and masses were similar to the native Hb was observed with all the linkers (greater than or equal to 75 %), with ternary and binary linker combinations (40-50%) and with individual linkers producing yields increasing in the following order: L1=1-3%, L2 approximate to L3 = 10-20% and L4 = 35-55%. The yield was two- to eightfold lower with method (B), except in the case of linkers L1-L3. Although the reassembly kinetics were always biphasic, with t(1/2) = 0.3-3.3 hours and 10-480 hours, the ratio of the amplitudes fast:slow was 1:0.6 with method (A) and 1:2.5 with method (B). These results are consistent with a scheme in which the slow HBL reassembly is dependent on a slow conversion of linker conformation at neutral pH from a reassembly incompetent to a reassembly competent conformation. Although all the linkers self-associate extensively at neutral pH, forming complexes ranging from dimers to >18-mers, the size of the complex does not affect the extent or rate of reassembly. The oxygen binding affinity of reassembled HBLs was similar to that of the native Hb, but their cooperativity was lower. A model of HBL reassembly was proposed which postulates that binding of linker dimers to two of the three T subunits of D causes conformational alterations resulting in the formation of complementary binding sites which permit lateral self-association of D subassemblies, and thus dictate the formation of a hexagonal structure due to the S-fold symmetry of D. (C) 1999 Academic Press. C1 Wayne State Univ, Sch Med, Dept Biochem & Mol Biol, Detroit, MI 48201 USA. Univ Tours, Lab Prot Complexes, F-37032 Tours, France. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Aarhus Univ, Inst Biol Sci, Dept Zoophysiol, DK-8000 Aarhus C, Denmark. RP Vinogradov, SN (reprint author), Wayne State Univ, Sch Med, Dept Biochem & Mol Biol, Detroit, MI 48201 USA. NR 28 TC 32 Z9 33 U1 0 U2 1 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUN 25 PY 1999 VL 289 IS 5 BP 1361 EP 1374 DI 10.1006/jmbi.1999.2825 PG 14 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 212NM UT WOS:000081223100015 PM 10373372 ER PT J AU Orji, CC Michalczyk, R Silks, LA AF Orji, CC Michalczyk, R Silks, LA TI Synthesis of 2 'beta-deoxy-[8-C-13;amino,9-N-15(2)] adenosine: Unusual annulation conditions to assemble the purine core SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID MAGNETIC-RESONANCE SPECTROSCOPY; NMR-SPECTROSCOPY; DNA OLIGONUCLEOTIDES; ENZYMATIC-SYNTHESIS; TRIPLET REPEATS; FRAGILE-X; RNA; HETERONUCLEAR; IDENTIFICATION; COMPLEXES AB Synthesis of 2'beta-Deoxy-[8-C-13;amino,9-N-15(2)] adenosine has been accomplished using a five-step process which employs a novel annulation of [C-13]formamide [N-(4-[N-15]amino-6-chloro-5-pyrimidinyl)] 2. To effect this dehydration, a complex of triethyl phosphite and TiCl2(i-OPr)(2) was used. 6-Chloro-[8-C-13; 9-N-15]purine was then converted in two steps to 2'beta-deoxy-[8-C-13;amino,9-N-15(2)]-adenosine. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Biosci & Biotechnol Grp, Los Alamos, NM 87545 USA. RP Silks, LA (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Biosci & Biotechnol Grp, CST-4,MS,E529, Los Alamos, NM 87545 USA. NR 49 TC 12 Z9 12 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD JUN 25 PY 1999 VL 64 IS 13 BP 4685 EP 4689 DI 10.1021/jo9824753 PG 5 WC Chemistry, Organic SC Chemistry GA 210ZV UT WOS:000081136200021 ER PT J AU Fein, JB Brady, PV Jain, JC Dorn, RI Lee, JU AF Fein, JB Brady, PV Jain, JC Dorn, RI Lee, JU TI Bacterial effects on the mobilization of cations from a weathered Pb-contaminated andesite SO CHEMICAL GEOLOGY LA English DT Article DE bacteria; leaching; weathering; dissolved materials; lead; biochemistry ID BACILLUS-SUBTILIS; REDUCTIVE DISSOLUTION; MINERAL DISSOLUTION; OLIVINE DISSOLUTION; SILICATE MINERALS; METAL ADSORPTION; ORGANIC-ACIDS; ION BINDING; CELL-WALLS; IRON AB Mobilization of contaminant Pb and other cations from a weathered andesite was examined by conducting water-rock leaching experiments to measure release rates of the major and minor elements found in the bulk rock. Experiments were conducted for over 600 h, at pH 3 and 6.5, as a function of grain size, and in the presence and absence of a common subsurface bacterial species, Bacillus subtilis. The acid leaching experiments exhibited enhanced Ph mobilities. The contact area between mineral surfaces and water controlled the amount of most elements leached into solution. Typically, bacteria accelerated the leaching of trace elements. However, major element levels were inversely correlated with bacterial content, and generally lower major element concentrations were observed in the presence of bacteria, relative to the bacteria-free systems. This effect was likely caused by bacterial enhancement of secondary mineral precipitation rates. Extremely low concentrations of Pb were leached into solution during the course of the experiments under conditions most closely approximating natural conditions (i.e., near neutral pH). Moreover, the release rate of Pb relative to other elements was low. Pb was associated with iron oxides precipitated in the rock pore spaces, and the experiments suggest that the iron oxides dissolved to a lesser extent than did other minerals in the rock matrix. The mobility of the Pb associated with these iron oxides was less than that of other heavy metals that were likely associated with the surrounding matrix. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Notre Dame, Notre Dame, IN 46556 USA. Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. Arizona State Univ, Dept Geog, Tempe, AZ 85287 USA. RP Fein, JB (reprint author), Univ Notre Dame, Notre Dame, IN 46556 USA. NR 52 TC 10 Z9 11 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JUN 24 PY 1999 VL 158 IS 3-4 BP 189 EP 202 DI 10.1016/S0009-2541(99)00047-9 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 206NC UT WOS:000080884900003 ER PT J AU Steinkamp, JA Lehnert, BE Lehnert, NM AF Steinkamp, JA Lehnert, BE Lehnert, NM TI Discrimination of damaged dead cells by propidium iodide uptake in immunofluorescently labeled populations analyzed by phase-sensitive flow cytometry SO JOURNAL OF IMMUNOLOGICAL METHODS LA English DT Article DE thymus cells; viability; propidium iodide; dye exclusion; phycoerythrin; Texas red; fluorescence lifetime; flow cytometry ID COLOR IMMUNOFLUORESCENCE; SINGLE LASER; VIABILITY; HOECHST-33342; PHYCOERYTHRIN; FLUOROCHROMES; ANTIGENS; LIFETIME; SIGNALS; SORTER AB We report a flow cytometric fluorescence lifetime-based method to discriminate damaged/dead from viable cells in immunofluorescently labeled populations using propidium iodide as a dye-exclusion viability probe. Fluorescence signals from propidium iodide and the anti-thymus cell-surface immunofluorescence marker fluorochromes, phycoerythrin and phycoerythrin/Texas Red (tandem conjugate), which have overlapping emission spectra with propidium iodide, are resolved based on differences in their fluorescence emission lifetimes using phase-sensitive detection. Mouse thymus cell samples were first labeled separately with anti-Thy 1.2 antibody directly conjugated to phycoerythrin and to phycoerythrin/Texas Red and propidium iodide. Labeled cells were then analyzed to determine the lifetimes of the immunofluorescence markers and propidium iodide. Based on these results, rat and mouse thymocytes labeled with anti-Thy 1.1 conjugated to phycoerythrin and anti-Thy 1.2 conjugated to phycoerythrin/Texas Red, respectively, were suspended in phosphate buffered saline containing propidium iodide, and were analyzed as they passed through a flow chamber and crossed a high-frequency, intensity-modulated (sinusoidal) laser excitation beam. The resulting immunofluorescence and propidium iodide signals were resolved based on differences in fluorescence lifetimes expressed as phase shifts using phase-sensitive detection and displayed as frequency distribution histograms and bivariate contour diagrams. This technology provides a new method to resolve immunofluorescence and propidium iodide signals from overlapping fluorescence emission spectra and a flow cytometric lifetime-based technique to quantify damaged/dead cells in immunofluorescence studies. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Steinkamp, JA (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Mail Stop 888, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [P41-RR013150, R01-RR07855] NR 33 TC 23 Z9 23 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1759 J9 J IMMUNOL METHODS JI J. Immunol. Methods PD JUN 24 PY 1999 VL 226 IS 1-2 BP 59 EP 70 DI 10.1016/S0022-1759(99)00053-8 PG 12 WC Biochemical Research Methods; Immunology SC Biochemistry & Molecular Biology; Immunology GA 211LD UT WOS:000081161800007 PM 10410972 ER PT J AU Tan, HS Espenson, JH AF Tan, HS Espenson, JH TI Regioselective hydroxylactonization of gamma,delta-unsaturated carboxylic acids with hydrogen peroxide catalyzed by methyltrioxorhenium SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE catalysis; rhenium; peroxide; lactonization ID METHYLRHENIUM TRIOXIDE; EPOXIDATION; DIHYDROXYLATION; DEACTIVATION; MECHANISM; KINETICS; LACTONES; OXIDES AB The oxidation of unsaturated carboxylic acids and esters to lactones with hydrogen peroxide is catalyzed by methyltrioxorhenium (MTO). The reaction proceeds regioselectively in high yield. On the basis of the results of this investigation and a comparison with previous work, a concerted process and mechanism have been suggested. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 20 TC 12 Z9 12 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD JUN 24 PY 1999 VL 142 IS 3 BP 333 EP 338 DI 10.1016/S1381-1169(98)00307-0 PG 6 WC Chemistry, Physical SC Chemistry GA 196JM UT WOS:000080305300005 ER PT J AU Maxwell, RS Kukkadapu, RK Amonette, JE Cho, H AF Maxwell, RS Kukkadapu, RK Amonette, JE Cho, H TI H-2 solid-state NMR investigation of terephthalate dynamics and orientation in mixed-anion hydrotalcite-like compounds SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID INTERCALATED WATER; NUCLEAR; SPECTROSCOPY; SYSTEMS AB The dynamics and orientations of interlayer terephthalate (TA) anions in mixed-anion hydrotalcite-like compounds [Mg1-xAlx(OH)(2)](A(y)B(1-y))(x/2). nH(2)O, where A = p-C6D4(COO)(2)(2-) and B = CO32-] were investigated by H-2 variable-temperature solid-state nuclear magnetic resonance (NMR) spectroscopy. Two dominant 003 d spacings, 7.6 and 14.2 Angstrom, were observed by X-ray diffraction (XRD) in these samples, suggesting that there were at least two interlayer environments. Over the range of layer charges studied (0.37 greater than or equal to x greater than or equal to 0.29), the intensity of the 7.6 Angstrom XRD peak increased with decreasing x, while the intensity of the 14.2 Angstrom peak increased with increasing x. Analysis of H-2 NMR line shapes indicated that the motion of some of the TA anions in every sample could be described as rotational diffusion (RD) about the C-COO- axis at temperatures ranging from 245 to 355 K, with the remainder being essentially immobile. The fraction of TA anions exhibiting rotation (X-RD), as estimated by H-2 NMR, was positively correlated with the TA content of the interlayer and thus seemed to correspond to the fraction of TA molecules in the 14.2 Angstrom phase. A large difference in XRD was observed between compounds having similar layer charge but different TA mole fractions. At temperatures of less than or equal to 330 K, X-RD increased with temperature. A secondary minimum in X-RD, however, was observed for each of the compounds at temperatures between 330 and 350 K. We conclude that the presence of CO32- anions in the interlayer regions, rather than layer charge, is the dominant factor affecting the dynamics and orientation of interlayer TA anions. C1 Pacific NW Lab, Environm Mol Sci Lab MSK8 98, Richland, WA 99352 USA. RP Pacific NW Lab, Environm Mol Sci Lab MSK8 98, POB 999, Richland, WA 99352 USA. EM hm.cho@pnl.gov NR 23 TC 10 Z9 10 U1 1 U2 4 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 JUN 24 PY 1999 VL 103 IS 25 BP 5197 EP 5203 DI 10.1021/jp990459j PG 7 WC Chemistry, Physical SC Chemistry GA 211FX UT WOS:000081151100007 ER PT J AU Henderson, MA Epling, WS Perkins, CL Peden, CHF Diebold, U AF Henderson, MA Epling, WS Perkins, CL Peden, CHF Diebold, U TI Interaction of molecular oxygen with the vacuum-annealed TiO2(110) surface: Molecular and dissociative channels SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ELECTRONIC-STRUCTURE; INTRINSIC DEFECTS; TITANIUM-DIOXIDE; TIO2 SURFACES; ADSORPTION; WATER; CO; PHOTOCATALYSIS; DESORPTION; H2O AB We have examined the interaction of molecular oxygen with the TiO2(110) surface using temperature-programmed desorption (TPD), isotopic labeling studies, sticking probability measurements, and electron energy loss spectroscopy (ELS). Molecular oxygen does not adsorb on the TiO:(110) surface in the temperature range between 100 and j00 K unless surface oxygen vacancy sites are present. These vacancy defects are generated by annealing the crystal at 850 K, and can be quantified reliably using water TPD. Adsorption of O-2 at 120 K on a TiO2(110) surface with 8% oxygen vacancies (about 4 x 10(13) sites/cm(2)) occurs with an initial sticking probability of 0.5-0.6 that diminishes as the surface is saturated. The saturation coverage at 120 K, as estimated by TPD uptake measurements, is approximately three times the surface vacancy population. Coverage-dependent TPD shows little or no Oz desorption below a coverage of 4 x 10(13) molecules/cm(2) (the vacancy population), presumably due to dissociative filling of the vacancy sites in a I:1 ratio. Above a coverage of 4 x 10(13) molecules/cm(2), a first-order O-2 TPD peak appears at 410 K. Oxygen molecules in this peak do not scramble oxygen atoms with either the surface or with ether coadsorbed oxygen molecules. Sequential exposures of O-16(2) and O-18(2) at 120 K indicate that each adsorbed O-2 molecule, irrespective of its adsorption sequence, has equivalent probabilities with respect to its neighbors to follow the two channels (molecular and dissociative), suggesting that Oz adsorption is not only precursor-mediated, as the sticking probability measurements indicate, but that all O-2 molecules reside in this precursor state at 120 K;. This precursor state may be associated with a weak 145 K O-2 TPD state observed at high Oz exposures. ELS measurements suggest charge transfer from the surface to the Oz molecule based on disappearance of the vacancy loss feature at 0.8 eV, and the appearance of a 3.8 eV loss that can be assigned to an adsorbed O-2(-) species based on comparisons with Ti-O-2: inorganic complexes in the literature. Utilizing results from recant spin-polarized DFT calculations in the literature, we propose a model when three O-2 molecules are bound in the vicinity of each vacancy site at 120 K. For adsorption temperatures above 150 E;, the dissociation channel completely dominates and the surface adsorbs oxygen in a 1:1 ratio with each vacancy site. ELS measurements indicate that the vacancies are filled, and the remaining oxygen adatom which is apparent in TPD, is transparent in ELS. On the basis of the variety of oxygen adsorption states observed in this study, further work is needed in order to determine which oxygen-related species play important roles in chemical and photochemical oxidation processes on TiO2 surfaces. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. RP Henderson, MA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999,MS K8-93, Richland, WA 99352 USA. RI Diebold, Ulrike/A-3681-2010; OI Diebold, Ulrike/0000-0003-0319-5256; Peden, Charles/0000-0001-6754-9928 NR 39 TC 351 Z9 353 U1 18 U2 162 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 JUN 24 PY 1999 VL 103 IS 25 BP 5328 EP 5337 DI 10.1021/jp990655q PG 10 WC Chemistry, Physical SC Chemistry GA 211FX UT WOS:000081151100024 ER PT J AU LoNostro, P Choi, SM Ku, CY Chen, SH AF LoNostro, P Choi, SM Ku, CY Chen, SH TI Fluorinated microemulsions: A study of the phase behavior and structure SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID BICONTINUOUS MICROEMULSIONS; DRUG-DELIVERY; FLUOROCARBONS; SYSTEMS; OXYGEN; MICROSTRUCTURE; INTERFACE; DIAGNOSIS; MIXTURES AB Fluorinated surfactants have been studied for their peculiar property to form micellar aggregates in water and oils (hydrocarbons or fluorocarbons) and to produce stable microemulsions. Because of their capacity to dissolve large amounts of gases (such as oxygen and carbon dioxide) and for their characteristic physicochemical properties, fluorocarbons have been tested for specific medical purposes and their microemulsions are among the most promising candidates for the production of suitable blood substitutes and other biocompatible fluids. We have synthesized a new partially fluorinated nonionic surfactant, namely, F(CF2)(7)-CO-(OCH2CH2)(7.2)-OCH3 (I), that forms stable microemulsions with water and perfluorocarbons such as perfluorooctane (PFO). In this paper we describe for the first time the phase behaviors of perfluorooctanoic acid (PFOA) in water/PFH and in water/PFO, and that of eater I in water/PFO. Small-angle neutron-scattering (SANS) experiments provide a detailed description of the microstructure of the H2O/PFO/PFOA ternary system. C1 Univ Florence, Dept Chem, I-50121 Florence, Italy. MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. Argonne Natl Lab, IPNS, Argonne, IL 60439 USA. RP LoNostro, P (reprint author), Univ Florence, Dept Chem, Via Gino Capponi 9, I-50121 Florence, Italy. RI Lo Nostro, Pierandrea/G-6585-2011 NR 22 TC 24 Z9 29 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 JUN 24 PY 1999 VL 103 IS 25 BP 5347 EP 5352 DI 10.1021/jp9827025 PG 6 WC Chemistry, Physical SC Chemistry GA 211FX UT WOS:000081151100026 ER PT J AU Cui, X Brenneman, M Meyne, J Oshimura, M Goodwin, EH Chen, DJ AF Cui, X Brenneman, M Meyne, J Oshimura, M Goodwin, EH Chen, DJ TI The XRCC2 and XRCC3 repair genes are required for chromosome stability in mammalian cells SO MUTATION RESEARCH-DNA REPAIR LA English DT Article DE XRCC2; XRCC3; chromosomal stability; chromosome rearrangement; human-hamster hybrid cells; DNA repair; homologous recombination; microcell-mediated chromosome transfer ID IONIZING-RADIATION; HOMOLOGOUS RECOMBINATION; SACCHAROMYCES-CEREVISIAE; CROSS-SENSITIVITY; TELOMERE REPEAT; RAD51 PROTEIN; HAMSTER-CELLS; MOUSE; INSTABILITY; RESISTANCE AB The irs1 and irs1SF hamster cell lines are mutated for the XRCC2 and XRCC3 genes, respectively. Both show heightened sensitivity to ionizing radiation and particularly to the DNA cross-linking chemical mitomycin C (MMC). Frequencies of spontaneous chromosomal aberration have previously been reported to be higher in these two cell lines than in parental. wild-type cell lines. Microcell-mediated chromosome transfer was used to introduce complementing or non-complementing human chromosomes into each cell line. irs1 cells received human chromosome 7 (which contains the human XRCC2 gene) or, as a control, human chromosome 4. irs1SF cells received human chromosome 14 (which contains the XRCC3 gene) or human chromosome 7. For each set of hybrid cell lines, clones carrying the complementing human chromosome recovered MMC resistance to near-wild-type levels, while control clones carrying noncomplementing chromosomes remained sensitive to MMC. Fluorescence in situ hybridization with a human-specific probe revealed that the human chromosome in complemented clones remained intact in almost all cells even after extended passage. However, the human chromosome in noncomplemented clones frequently underwent chromosome rearrangements including breaks, deletions, and translocations. Chromosome aberrations accumulated slowly in the noncomplemented clones over subsequent passages, with some particular deletions and unbalanced translocations persistently transmitted throughout individual subclones, Our results indicate that the XRCC2 and XRCC3 genes, which are now considered members of the RAD51 gene family, play essential roles in maintaining chromosome stability during cell division. This may reflect roles in DNA repair, possibly via homologous recombination. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Tottori Univ, Sch Life Sci, Dept Mol & Cell Genet, Tottori 6838503, Japan. RP Goodwin, EH (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Mail Stop M888, Los Alamos, NM 87545 USA. FU NCI NIH HHS [CA74046] NR 28 TC 99 Z9 109 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8777 J9 MUTAT RES-DNA REPAIR JI Mutat. Res.-DNA Repair PD JUN 23 PY 1999 VL 434 IS 2 BP 75 EP 88 DI 10.1016/S0921-8777(99)00010-5 PG 14 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 213AF UT WOS:000081249300002 PM 10422536 ER PT J AU Hirth, JP Hoagland, RG Holian, BL Germann, TC AF Hirth, JP Hoagland, RG Holian, BL Germann, TC TI Shock relaxation by a strain induced martensitic phase transformation SO ACTA MATERIALIA LA English DT Article DE computer simulation; martensite shear; metals; shock ID DEFORMATION AB As an alternative to the relaxation of a uniaxial shock loaded state by slip or twinning, a model is developed for relaxation by a martensitic transformation. For the case of copper shocked in a (110) direction, the elastically loaded, body-centered-orthorhombic structure is shown to relax to an isostatically strained f.c.c. crystal by a shuffle-type martensitic transformation. The specific model agrees well with results from an atomistic computer simulation of the shock relaxation process. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hoagland, RG (reprint author), Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. RI Hoagland, Richard/G-9821-2012 NR 20 TC 9 Z9 9 U1 0 U2 3 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 JUN 22 PY 1999 VL 47 IS 8 BP 2409 EP 2415 DI 10.1016/S1359-6454(99)00108-1 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 216JU UT WOS:000081439600010 ER PT J AU Schreckenbach, G AF Schreckenbach, G TI The Fe-57 nuclear magnetic resonance shielding in ferrocene revisited. A density-functional study of orbital energies, shielding mechanisms, and the influence of the exchange-correlation functional SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INCLUDING ATOMIC ORBITALS; NMR CHEMICAL-SHIFTS; CORRECT ASYMPTOTIC-BEHAVIOR; GAUSSIAN-BASIS SET; PERTURBATION-THEORY; HARTREE-FOCK; CORRELATION POTENTIALS; PRACTICAL TOOL; ELECTRON-GAS; TENSORS AB The Fe-57 nuclear magnetic resonance (NMR) shielding and chemical shift in ferrocene, Fe(C5H5)(2), are studied using density functional theory (DFT) and gauge-including atomic orbitals (GIAO). Electronic factors contributing to the chemical shift are discussed in detail. It is shown that the chemical shift is entirely determined by paramagnetic contributions which in turn are dominated by metal based occupied-virtual d-->d couplings. In particular, the HOMO-1(a(1)') and the HOMO (e(2)') couple with the LUMO (e(1)"). It is argued that the Fe-57 nucleus in ferrocene is less shielded than in the reference compound (iron pentacarbonyl) due to a smaller HOMO-LUMO gap, resulting in stronger interactions between occupied and virtual orbitals. The influence of the XC functional on the calculated molecular orbital (MO) energies of frontier orbitals is discussed. Different generalized gradient approximations (GGA) give similar results whereas hybrid functionals that incorporate part of the Hartree-Fock exchange stabilize occupied MOs strongly and destabilize virtual MOs. HOMO-LUMO gaps are nearly doubled as a result. The previously noted "dramatic influence" of different exchange-correlation (XC) functionals on the calculated chemical shifts is analyzed. The influence of the XC functional is realized through the paramagnetic part of the shielding; hybrid functionals increase it in absolute terms as compared to pure DFT (GGA). It is argued that three factors are responsible. These are (i) the increased occupied-virtual gaps, (ii) the more diffuse nature of virtual orbitals, and (iii) the coupling due to the Hartree-Fock exchange in hybrid functionals. The last two factors increase the paramagnetic part of the shielding, and this effect is only partly reversed by the increased occupied-virtual gaps that result in reduced interactions. It is suggested that new model XC functionals for the calculation of NMR shieldings should be developed aiming at both, accurate energetics and a correct representation of the XC potential. The wealth of precise experimental NMR data could be used as input for this purpose. (C) 1999 American Institute of Physics. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Seaborg Inst Transactinium Sci, Los Alamos, NM 87545 USA. RP Schreckenbach, G (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B268, Los Alamos, NM 87545 USA. NR 96 TC 64 Z9 64 U1 1 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 22 PY 1999 VL 110 IS 24 BP 11936 EP 11949 DI 10.1063/1.479133 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 204CN UT WOS:000080745500033 ER PT J AU Fried, LE Howard, WM AF Fried, LE Howard, WM TI The equation of state of supercritical HF, HCl, and reactive supercritical mixtures containing the elements H, C, F, and Cl SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LIQUID-HYDROGEN CHLORIDE; COMPUTER-SIMULATION; HIGH-PRESSURE; FLUID MIXTURES; HIGH-DENSITY; TEMPERATURE-MEASUREMENTS; SHOCK COMPRESSION; MOLECULAR-SYSTEMS; OF-STATE; FLUORIDE AB We develop a model of chemical equilibrium mixtures containing the elements H, C, F, and Cl. The model is based on a recently developed equation of state for the exponential-6 fluid, combined with a simple equation of state for condensed carbon. We show that the shock response of a wide variety of molecular and polymeric fluorocarbons and chlorocarbons can be modeled as a chemical equilibrium mixture of a small number of dissociation product molecules. In particular, we predict that shocked polyvinylidine fluoride (PVF2) decomposes into a fluid phase composed mostly of HF, and a phase containing condensed carbon. HF is known to strongly associate in the supercritical fluid phase. We predict that such an association also occurs under shock conditions. (C) 1999 American Institute of Physics. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Fried, LE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Fried, Laurence/L-8714-2014 OI Fried, Laurence/0000-0002-9437-7700 NR 61 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 22 PY 1999 VL 110 IS 24 BP 12023 EP 12032 DI 10.1063/1.479138 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 204CN UT WOS:000080745500041 ER PT J AU Honea, EC Ogura, A Peale, DR Felix, C Murray, CA Raghavachari, K Sprenger, WO Jarrold, MF Brown, WL AF Honea, EC Ogura, A Peale, DR Felix, C Murray, CA Raghavachari, K Sprenger, WO Jarrold, MF Brown, WL TI Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ATTENUATED-TOTAL-REFLECTION; INTERATOMIC FORCE-FIELDS; RARE-GAS MATRICES; AMORPHOUS-SILICON; SILVER CLUSTERS; EQUILIBRIUM STRUCTURES; ULTRATHIN FILMS; ARGON MATRICES; BULK PHASES; SPECTRA AB The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton (SPP) enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N-2 on a liquid He cooled substrate. Raman spectra from monodisperse samples of the smaller clusters studied, Si-4, Si-6 and Si-7, show sharp, well-resolved, vibrations which are in good agreement with predictions based on ab initio calculations. From these comparisons we confirm that Si-4 is a planar rhombus, and assign Si-6 as a distorted octahedron and Si-7 as a pentagonal bypyramid. Si-5 depositions down to 5 eV did not reveal a measurable Raman spectrum under our experimental conditions. Evidence for cluster-cluster aggregation (or fragmentation) was observed under some conditions, even for a "magic number" cluster such as Si-6. The spectra of the aggregated small clusters were identical to those observed for directly deposited larger cluster "bands," such as Si25-35. The Raman spectra of the aggregated clusters bear some similarity to those of bulk amorphous silicon. Cluster-deposited thin films were prepared by sublimating the matrix material. Even under these "soft landing" conditions, changes in the Raman spectrum are observed with the thin films showing even greater similarity to amorphous silicon. (C) 1999 American Institute of Physics. [S0021-9606(99)70521-0]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NEC Corp Ltd, Silicon Syst Res Labs, Tsukuba, Ibaraki, Japan. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 85 TC 79 Z9 79 U1 2 U2 21 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 JUN 22 PY 1999 VL 110 IS 24 BP 12161 EP 12172 DI 10.1063/1.479153 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 204CN UT WOS:000080745500056 ER PT J AU Kiely, JD Houston, JE AF Kiely, JD Houston, JE TI Contact hysteresis and friction of alkanethiol self-assembled monolayers on gold SO LANGMUIR LA English DT Article ID ATOMIC-FORCE MICROSCOPY; CHAIN-LENGTH DEPENDENCE; MOLECULAR ASSEMBLIES; UV PHOTOOXIDATION; SURFACE; FILMS; AU(111); TRANSITION; OXIDATION; ADHESION AB Nanoindentation has been combined with nanometer-scale friction measurements to identify dissipative mechanisms responsible for friction in hexadecanethiol self-assembled monolayers on Au. We have demonstrated that friction is primarily due to viscoelastic relaxations within the films, which give rise to contact hysteresis when deformation rates are within the ranges of 5 and 200 Angstrom/s. We observe that this contact hysteresis increases with exposure to air such that the friction coefficient increases from 0.004 to 0.075 when films are exposed to air for 40 days. Both hysteresis and friction increase with probe speed, and we present a model of friction that characterizes this speed dependence and that also predicts a linear dependence of friction on normal force in thin organic films. Finally, we identify several short-term wear regimes and identify that wear changes dramatically when films age. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Kiely, JD (reprint author), Sandia Natl Labs, Surface & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 36 TC 54 Z9 54 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUN 22 PY 1999 VL 15 IS 13 BP 4513 EP 4519 DI 10.1021/la9813681 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 210TC UT WOS:000081119900034 ER PT J AU Oden, PI AF Oden, PI TI Gravimetric sensing of metallic deposits using an end-loaded microfabricated beam structure (vol B53, pg 191, 1998) SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Correction C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Oden, PI (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD JUN 22 PY 1999 VL 56 IS 3 BP 259 EP 259 PG 1 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 212EL UT WOS:000081203900012 ER PT J AU Balasubramanian, M Melendres, CA Mansour, AN AF Balasubramanian, M Melendres, CA Mansour, AN TI An X-ray absorption study of the local structure of cerium in electrochemically deposited thin films SO THIN SOLID FILMS LA English DT Article DE cerium; corrosion; electrochemistry; X-ray absorption ID FINE-STRUCTURE; EDGE; INHIBITORS; CORROSION; ALUMINUM; ALLOYS; EXAFS AB We have utilized the technique of X-ray absorption fine structure (XAFS) to study the oxidation state and structure of cerium in electrochemically deposited thin films of cerium oxide (hydroxide). We find that anodic deposition results in a hydrous cerium oxide phase in which the oxidation state of cerium is 4+. This material is highly structurally disordered but still has a medium range local structure (similar to 4 Angstrom) similar to CeO2. On the other hand, cathodic deposition leads to a Ce3+ phase, which is susceptible to oxidation on exposure to air or by dissolved oxygen in solution. Our results may be relevant to understanding the structure of cerium inhibitors incorporated in corrosion films on aluminium and its alloys. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. USN, Ctr Surface Warfare, Carderock Div, Bethesda, MD 20817 USA. RP Balasubramanian, M (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 41 Z9 44 U1 1 U2 7 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 JUN 22 PY 1999 VL 347 IS 1-2 BP 178 EP 183 DI 10.1016/S0040-6090(98)01754-4 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 207RP UT WOS:000080949800025 ER PT J AU Moulzolf, SC Lad, RJ Blau, PJ AF Moulzolf, SC Lad, RJ Blau, PJ TI Microstructural effects on the friction and wear of zirconia films in unlubricated sliding contact SO THIN SOLID FILMS LA English DT Article DE zirconium oxide film; friction; wear; microstructure; sliding contact ID THIN-FILMS; PERFORMANCE; MICROPROBE; SURFACES; COATINGS; WATER; TESTS AB Friction and wear of sapphire and steel counterfaces sliding on unlubricated thin films of zirconia were studied using conventional multiple pass pin-on-disk testing and single pass testing with a 'friction microprobe'. The zirconia films were grown by electron-cyclotron-resonance (ECR) oxygen plasma assisted deposition on r-cut (01 (1) over bar 2) sapphire using different growth parameters to produce films with varying degrees of order. The microstructure of the zirconia films is correlated to the widely varying observed friction and wear characteristics. Anisotropic stress effects produced during scratch tests are also presented. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Maine, Surface Sci & Technol Lab, Orono, ME 04469 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Moulzolf, SC (reprint author), Univ Maine, Surface Sci & Technol Lab, Orono, ME 04469 USA. RI Lad, Robert/G-1669-2014 NR 20 TC 30 Z9 34 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 JUN 22 PY 1999 VL 347 IS 1-2 BP 220 EP 225 DI 10.1016/S0040-6090(99)00046-2 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 207RP UT WOS:000080949800031 ER PT J AU Chamberlin, DR Brundermann, E Haller, EE AF Chamberlin, DR Brundermann, E Haller, EE TI Planar contact geometry for far-infrared germanium lasers SO APPLIED PHYSICS LETTERS LA English DT Article ID GE; EMISSION AB We demonstrate operation of p-Ge far-infrared lasers with a planar contact geometry. The smallest laser crystal with this geometry has a maximum pulse length of 22 mu s, which is 10% longer than the pulse length of comparably doped lasers with the traditional contact geometry. Calculations of the electric field distribution show that the fraction of active crystal volume for this new geometry is similar to four times larger than that of traditional geometries. Experiments and calculations reveal that in the planar design, the minimum applied voltage necessary for lasing decreases when the crystal geometry approaches a flat planar structure. This is due to a significant increase of the total electric field caused by the Hall effect. (C) 1999 American Institute of Physics. [S0003-6951(99)01025-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chamberlin, DR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Bruendermann, Erik/J-7186-2016 OI Bruendermann, Erik/0000-0003-4119-3489 NR 14 TC 7 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1999 VL 74 IS 25 BP 3761 EP 3763 DI 10.1063/1.124219 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600003 ER PT J AU Geohegan, DB Puretzky, AA Rader, DJ AF Geohegan, DB Puretzky, AA Rader, DJ TI Gas-phase nanoparticle formation and transport during pulsed laser deposition of Y(1)Ba(2)Cu(3)O(7-d) SO APPLIED PHYSICS LETTERS LA English DT Article ID ABLATION; YBA2CU3O7-X AB The gas-phase growth and transport of nanoparticles are characterized at the low background oxygen pressures used for pulsed laser deposition of high-T(c) Y(1)Ba(2)Cu(3)O(7-d) superconducting films. Onset times and pressures for gas-phase nanoparticle formation were determined by intensified charge-coupled device imaging and optical spectroscopy of laser-induced fluorescence from diatomic oxides and Rayleigh scattering from gas-suspended nanoparticles. Nanoparticles are detected for oxygen pressures above 175 mTorr at room temperature, with growth continuing during seconds within the cloud of stopped vapor near the heater surface. Elevated heater temperatures create background density gradients which result in reduced resistance to the initial plume expansion. The temperature gradient also moves nanoparticles away from the heater surface as they grow, effectively limiting the time and spatial confinement necessary for continued growth or aggregation, and inhibiting deposition by thermophoresis. (C) 1999 American Institute of Physics. [S0003-6951(99)02225-1]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Sandia Natl Labs, Engn Sci Ctr, Albuquerque, NM 87185 USA. RP Geohegan, DB (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. EM odg@ornl.gov RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 14 TC 50 Z9 50 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1999 VL 74 IS 25 BP 3788 EP 3790 DI 10.1063/1.124180 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600012 ER PT J AU Sharp, JW Sales, BC Mandrus, DG Chakoumakos, BC AF Sharp, JW Sales, BC Mandrus, DG Chakoumakos, BC TI Thermoelectric properties of Tl2SnTe5 and Tl2GeTe5 SO APPLIED PHYSICS LETTERS LA English DT Article ID THALLIUM-TIN-TELLURIUM; TERNARY-SYSTEM; THERMAL-CONDUCTIVITY AB We report on the thermoelectric properties of two ternary tellurides with known crystal structures. Both compounds have a very low lattice thermal conductivity. Tl2SnTe5 appears to have a p-type figure of merit about the same as that of Bi2Te3, the best thermoelectric material among binary compounds. We have synthesized mainly polycrystalline samples, but a few small crystals have been grown and used for electrical measurements. Prospects for further improvement of these materials are discussed. (C) 1999 American Institute of Physics. [S0003-6951(99)02925-3]. C1 Marlow Ind, Div Res & Dev, Dallas, TX 75238 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Sharp, JW (reprint author), Marlow Ind, Div Res & Dev, Dallas, TX 75238 USA. RI Mandrus, David/H-3090-2014; Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 17 TC 49 Z9 49 U1 2 U2 12 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 JUN 21 PY 1999 VL 74 IS 25 BP 3794 EP 3796 DI 10.1063/1.124182 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600014 ER PT J AU Coulthard, I Freeland, JW Winarski, R Ederer, DL Jiang, JS Inomata, A Bader, SD Callcott, TA AF Coulthard, I Freeland, JW Winarski, R Ederer, DL Jiang, JS Inomata, A Bader, SD Callcott, TA TI Soft x-ray absorption of a buried SmCo film utilizing substrate fluorescence detection SO APPLIED PHYSICS LETTERS LA English DT Article ID CIRCULAR-DICHROISM; THIN-FILMS; PHOTOABSORPTION; SUPERLATTICES AB Oxygen K-shell x-ray fluorescence was monitored from the MgO substrate of a metallic heterostructure system containing a buried SmCo permanent magnet layer. This fluorescence was utilized as a detector to record transmission yield spectra for the SmCo film at both the Co-L-3,L-2 and Sm-M-5,M-4 absorption edges. Ordinarily, traditional transmission yield spectroscopy in the soft x-ray regime is impossible to perform with films on single-crystal substrates. The measured intensity ratios agree with simulations to confirm the thickness information. The potential and limitations of this technique are discussed in comparison to standard total electron and fluorescence yield techniques and magnetic circular dichroism. (C) 1999 American Institute of Physics. [S0003-6951(99)04525-8]. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Coulthard, I (reprint author), Argonne Natl Lab, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013 NR 13 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1999 VL 74 IS 25 BP 3806 EP 3808 DI 10.1063/1.124186 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600018 ER PT J AU Gilbert, CJ Ager, JW Schroeder, V Ritchie, RO Lloyd, JP Graham, JR AF Gilbert, CJ Ager, JW Schroeder, V Ritchie, RO Lloyd, JP Graham, JR TI Light emission during fracture of a Zr-Ti-Ni-Cu-Be bulk metallic glass SO APPLIED PHYSICS LETTERS LA English DT Article ID AMORPHOUS-ALLOYS; MECHANICAL-PROPERTIES; TOUGHNESS; BEHAVIOR AB A light emission phenomenon observed during dynamic fracture of a bulk metallic glass, Zr41.2Ti13.8Cu12.5Ni10Be22.5 (at. %), has been investigated using Charpy V-notch impact specimens. Unlike more conventional crystalline metals, these Zr-based amorphous alloys emit intense flashes of visible light when ruptured. The mechanisms for this surprising behavior are unknown and the phenomenon remains uncharacterized. Here we report spectroscopic measurements of the light emitted from specimens fractured in both room air and nitrogen gas. Spectra acquired from specimens ruptured in air exhibited a single broad peak, which could be fit to a blackbody temperature of similar to 3175 K. Emission from specimens fractured in nitrogen, however, was at least four orders of magnitude less intense. The spectrum was shifted to the red with an effective blackbody temperature of similar to 1400 K. Fracture surfaces of specimens ruptured in both air and nitrogen exhibited local melting, providing further evidence of intense heating during fracture. Based on these observations we argue that the intense light emission in air is associated with pyrolysis of fresh material exposed during rupture. (C) 1999 American Institute of Physics. [S0003-6951(99)04825-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Gilbert, CJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008; OI Ritchie, Robert/0000-0002-0501-6998; Ager, Joel/0000-0001-9334-9751 NR 18 TC 72 Z9 74 U1 1 U2 19 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1999 VL 74 IS 25 BP 3809 EP 3811 DI 10.1063/1.124187 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600019 ER PT J AU Gapud, AA Wu, JZ Fang, L Yan, SL Xie, YY Siegal, MP Overmyer, DL AF Gapud, AA Wu, JZ Fang, L Yan, SL Xie, YY Siegal, MP Overmyer, DL TI Supercurrents in HgBa2CaCu2O6+delta and TlBa2CaCu2O7 epitaxial thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID CRITICAL-CURRENT DENSITY; SUPERCONDUCTORS AB The availability of high-quality epitaxial thin films of HgBa2CaCu2O6+delta (Hg-1212) and TlBa2CaCu2O7 (Tl-1212) with high critical current densities (J(c)) has made it possible to examine and compare the J(c) of these species. Results reveal that the J(c) of 1212 species have very similar temperature behavior at low fields, strongly suggesting that the 30 K shift in critical temperature (T-c) induced by the exchange of Hg and Tl in the 1212 structure is due largely to a change in charge carrier density and/or electronic band structure. (C) 1999 American Institute of Physics. [S0003-6951(99)02825-9]. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Gapud, AA (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. OI Gapud, Albert/0000-0001-9048-9230 NR 18 TC 5 Z9 5 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 JUN 21 PY 1999 VL 74 IS 25 BP 3878 EP 3880 DI 10.1063/1.124210 PG 3 WC Physics, Applied SC Physics GA 206CB UT WOS:000080857600042 ER PT J AU Maria, L Campello, MP Domingos, A Santos, I Andersen, R AF Maria, L Campello, MP Domingos, A Santos, I Andersen, R TI Synthesis and structure of uranium(III) complexes with dihydrobis(pyrazolyl)borates SO JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS LA English DT Article ID ACTINIDE POLY(PYRAZOL-1-YL)BORATE COMPLEXES; CHEMISTRY; COORDINATION; LIGAND; 3-CENTER; ADDUCTS AB The synthesis of the novel uranium(III) complexes [UI2{H2B(3(t)Bu,5Me-pz)(2)}(THF)(2)] 1, [UI2{H2B(3(t)Bu,5Me-pz)(2)}(OPPh3)(2)] 2 (3(t)Bu,5Me-pz = 3-tert-butyl-5-methylpyrazolyl) and [U{Ph2B(pz)(2)}(3)] 3 are reported. The molecular structures have been determined by single crystal X-ray diffraction. In monomeric complexes 1 and 2 the U-III is seven-co-ordinated by the two pyrazolyl nitrogens, the two iodides and two oxygen atoms of the neutral ligands and by an agostic B-H ... U interaction. In monomeric 3 the uranium is six-co-ordinated by the nitrogen atoms of the chelating Ph2B(pz)(2) ligands which are arranged in a trigonal prismatic geometry around the uranium. C1 Inst Tecnol & Nucl, Dept Quim, P-2686 Sacavem, Portugal. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Santos, I (reprint author), Inst Tecnol & Nucl, Dept Quim, P-2686 Sacavem, Portugal. RI Maria, Leonor/I-5868-2013; Santos, Isabel /J-6036-2013; Campello, Maria Paula/B-5402-2010; Cabral Campello, Maria Paula/J-6851-2013 OI Maria, Leonor/0000-0001-7100-6627; Santos, Isabel /0000-0001-7362-0022; Cabral Campello, Maria Paula/0000-0003-2017-3358 NR 28 TC 30 Z9 30 U1 0 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0300-9246 J9 J CHEM SOC DALTON JI J. Chem. Soc.-Dalton Trans. PD JUN 21 PY 1999 IS 12 BP 2015 EP 2020 DI 10.1039/a900744j PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 214BT UT WOS:000081308300022 ER PT J AU Schmid, GJ Deleplanque, MA Lee, IY Stephens, FS Vetter, K Clark, RM Diamond, RM Fallon, P Macchiavelli, AO MacLeod, RW AF Schmid, GJ Deleplanque, MA Lee, IY Stephens, FS Vetter, K Clark, RM Diamond, RM Fallon, P Macchiavelli, AO MacLeod, RW TI A gamma-ray tracking algorithm for the GRETA spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE GRETA; high-multiplicity gamma-ray events ID SEGMENTED GERMANIUM DETECTORS; COMPTON POLARIMETER AB We discuss a gamma-ray tracking algorithm that has been developed for the proposed gamma-ray energy tracking array (GRETA). This algorithm has been designed so as to maximize the resolving power for detecting high-multiplicity gamma-ray events. The conceptual basis for this algorithm will be presented. In addition, Monte Carlo simulated data will be used to assess performance over a large range of relevant parameters. A discussion of the potential gamma-ray polarimeter performance of GRETA is also presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Schmid, GJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 9 TC 102 Z9 102 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 JUN 21 PY 1999 VL 430 IS 1 BP 69 EP 83 DI 10.1016/S0168-9002(99)00188-6 PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 209UF UT WOS:000081066700009 ER PT J AU Ackerbauer, P Werner, J Breunlich, WH Cargnelli, M Fussy, S Jeitler, M Kammel, P Marton, J Scrinzi, A Zmeskal, J Bistirlich, J Crowe, KM Kurck, J Petitjean, C Sherman, RH Bossy, H Daniel, H Hartmann, FJ Neumann, W Schmidt, G Faifman, MP AF Ackerbauer, P Werner, J Breunlich, WH Cargnelli, M Fussy, S Jeitler, M Kammel, P Marton, J Scrinzi, A Zmeskal, J Bistirlich, J Crowe, KM Kurck, J Petitjean, C Sherman, RH Bossy, H Daniel, H Hartmann, FJ Neumann, W Schmidt, G Faifman, MP TI Experimental investigation of muon-catalyzed dt fusion at cryogenic temperatures SO NUCLEAR PHYSICS A LA English DT Article DE muon catalyzed fusion; nuclear reaction; H-3(d,n); E at rest; measured neutron spectra; deuterium-tritium fusion reaction catalyzed by muons; deuterium-tritium fusion reaction in muonic; molecules; atoms and molecules, muonic; muonic molecule formation; excited state muon transfer ID D-T-FUSION; KINETIC-ENERGY DISTRIBUTION; 3-BODY MOLECULAR FORMATION; MESIC MOLECULES; TRANSFER RATES; OMEGA-S; HYDROGEN; DEUTERIUM; MIXTURE; COLLISIONS AB An experimental investigation of muon-catalyzed fusion (mu CF) in gaseous, liquid and solid mixtures of deuterium and tritium was performed. The target conditions included the range of densities of 0.03 less than or similar to phi less than or similar to 1.5, tritium concentrations of 2% less than or similar to c(r) less than or similar to 90% and temperatures of 13 less than or similar to T less than or similar to 40K. The study was based on the analysis of observed cycling rates extracted from the measured time distributions of the fusion neutrons. For the first time, the density dependence of the rates lambda((dt mu)d)(0) for the dt mu molecule formation in collisions of t mu atoms in the lower (F=0) hyperfine state with D-2 molecules was determined experimentally. Evidence for the proposed effects of below-threshold resonances on molecular formation was found. Measurements at low temperatures in mixtures of different molecular compositions revealed a clear predominance of the lambda((dt mu)d)(0) formation rate. The probability q(1s) for d mu atoms to reach the ground state was determined as a function of density and tritium concentration. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Austrian Acad Sci, Inst Medium Energy Phys, A-1090 Vienna, Austria. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Tech Univ Munich, Dept Phys, D-85747 Garching, Germany. Russian Res Ctr, Kurchatov Inst, Moscow 123182, Russia. RP Austrian Acad Sci, Inst Medium Energy Phys, Boltzmanngasse 3, A-1090 Vienna, Austria. RI Jeitler, Manfred/H-3106-2012; Marton, Johann/H-2668-2012 OI Marton, Johann/0000-0001-5139-7720 NR 80 TC 21 Z9 21 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD JUN 21 PY 1999 VL 652 IS 4 BP 311 EP 338 DI 10.1016/S0375-9474(99)00168-2 PG 28 WC Physics, Nuclear SC Physics GA 213WC UT WOS:000081295400001 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH 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 Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Potopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH 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 Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Potopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Search for charged Higgs bosons in decays of top quark pairs SO PHYSICAL REVIEW LETTERS LA English DT Article ID PRODUCTION CROSS-SECTION; DETECTOR; MASS AB We present a search for charged Higgs bosons in decays of pair-produced top quarks using 109.2 +/- 5.8 pb(-1) of data recorded from p (p) over bar collisions at root s 1.8 TeV by the D0 detector during 1992-1996 at the Fermilab Tevatron. No evidence is found for charged Higgs production, and most parts of the [MH+, tan beta] parameter space where the decay t --> H(+)b has a branching fraction close to or larger than that for t --> W(+)b are excluded at 95% confidence level. Assuming m(t) = 175 GeV and sigma(p (p) over bar --> t (t) over bar) = 5.5 pb, for MH+ = 60 GeV, we exclude tan beta < 0.97 and tan beta > 40.9. C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Univ Los Andes, Bogota, Colombia. CEA, Serv Phys Particules, DAPNIA, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), NYU, New York, NY 10003 USA. RI Sznajder, Andre/L-1621-2016; Kim, Sun Kee/G-2042-2015; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Chekulaev, Sergey/O-1145-2015 OI Sznajder, Andre/0000-0001-6998-1108; Baarmand, Marc/0000-0002-9792-8619; Kim, Sun Kee/0000-0002-0013-0775; Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; Belyaev, Alexander/0000-0002-1733-4408; NR 20 TC 88 Z9 88 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 JUN 21 PY 1999 VL 82 IS 25 BP 4975 EP 4980 DI 10.1103/PhysRevLett.82.4975 PG 6 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300007 ER PT J AU Passchier, I Alarcon, R Bauer, TS Boersma, D van den Brand, JFJ van Buuren, LD Bulten, HJ Ferro-Luzzi, M Heimberg, P Higinbotham, DW de Jager, CW Klous, S Kolster, H Lang, J Militsyn, BL Nikolenko, D Nooren, GJL Norum, BE Poolman, HR Rachek, I Simani, MC Six, E Szczerba, D de Vries, H Wang, K Zhou, ZL AF Passchier, I Alarcon, R Bauer, TS Boersma, D van den Brand, JFJ van Buuren, LD Bulten, HJ Ferro-Luzzi, M Heimberg, P Higinbotham, DW de Jager, CW Klous, S Kolster, H Lang, J Militsyn, BL Nikolenko, D Nooren, GJL Norum, BE Poolman, HR Rachek, I Simani, MC Six, E Szczerba, D de Vries, H Wang, K Zhou, ZL TI Charge form factor of the neutron from the reaction (2)(H)over-right-arrow((e)over-right- arrow,e ' n)p SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUASI-ELASTIC SCATTERING; POLARIZED ELECTRONS; INTERNAL TARGET; STORAGE-RING; HE-3; SPECTROMETER; NIKHEF; RADIUS AB We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an electron storage ring at a beam energy of 720 MeV. A Siberian snake was employed to preserve longitudinal polarization at the interaction paint. Vector-polarized deuterium was produced by an atomic beam source and injected into an open-ended cylindrical cell, internal to the electron storage ring. The spin correlation parameter A(ed)(V) was measured for the reaction 2 (H) over right arrow((e) over right arrow, e' n)p at a four-momentum transfer squared of 0.21 (GeV/c)(2) from which a value for the charge form factor of the neutron was extracted. C1 Natl Inst Nucl & High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Utrecht, Dept Phys, NL-3508 TA Utrecht, Netherlands. Vrije Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. ETH Zurich, Inst Teilchenphys, CH-8093 Zurich, Switzerland. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. RP Passchier, I (reprint author), Natl Inst Nucl & High Energy Phys, POB 41882, NL-1009 DB Amsterdam, Netherlands. RI Higinbotham, Douglas/J-9394-2014 OI Higinbotham, Douglas/0000-0003-2758-6526 NR 28 TC 202 Z9 202 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 JUN 21 PY 1999 VL 82 IS 25 BP 4988 EP 4991 DI 10.1103/PhysRevLett.82.4988 PG 4 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300010 ER PT J AU Rentmeester, MCM Timmermans, RGE Friar, JL de Swart, JJ AF Rentmeester, MCM Timmermans, RGE Friar, JL de Swart, JJ TI Chiral two-pion exchange and proton-proton partial-wave analysis SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-SHIFT ANALYSIS; COUPLING-CONSTANT; SCATTERING DATA; NUCLEAR-FORCES; LAGRANGIANS; POTENTIALS; MASSES AB The chiral two-pion exchange component of the long-range pp interaction is studied in an energy-dependent partial-wave analysis. We demonstrate its presence and importance and determine the chiral parameters c(i) (i = 1, 3, 4). The values agree well with those obtained from pion-nucleon amplitudes. C1 Univ Groningen, KVI, NL-9747 AA Groningen, Netherlands. Univ Nijmegen, Inst Theoret Phys, NL-6500 GL Nijmegen, Netherlands. Flinders Univ S Australia, Dept Phys, Bedford Pk, SA 5042, Australia. Univ Utrecht, Inst Theoret Phys, NL-3584 CC Utrecht, Netherlands. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Rentmeester, MCM (reprint author), Univ Groningen, KVI, Zernikelaan 25, NL-9747 AA Groningen, Netherlands. NR 48 TC 139 Z9 139 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 JUN 21 PY 1999 VL 82 IS 25 BP 4992 EP 4995 DI 10.1103/PhysRevLett.82.4992 PG 4 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300011 ER PT J AU Yethiraj, M Christen, DK Paul, DM Miranovic, P Thompson, JR AF Yethiraj, M Christen, DK Paul, DM Miranovic, P Thompson, JR TI Flux lattice symmetry in V3Si: Nonlocal effects in a high-kappa superconductor SO PHYSICAL REVIEW LETTERS LA English DT Article ID LINE-LATTICE; ERNI2B2C; YNI2B2C AB In the high-kappa cubic superconductor V3Si, phase transitions of the flux lattice structure occur as a function of applied field and temperature. With the field parallel to the fourfold [001] axis, the flux lattice transforms from triangular to square symmetry at approximately 1 T. With the field parallel to the twofold [110] axis, the lattice, which is a nearly perfect hexagonal array at the lowest fields, distorts as the field is increased; the rate of increase in this distortion changes abruptly at 1.3 T. As T-c is approached, the system tends towards a more isotropic hexagonal array of the flux lines. These transitions are largely but not completely in agreement with a recent theory of the effects on the flux line arrangements of nonlocal electrodynamics in the London limit. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. Univ Belgrade, Inst Phys, YU-11001 Belgrade, Yugoslavia. Univ Tennessee, Knoxville, TN 37996 USA. RP Yethiraj, M (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 9 TC 41 Z9 41 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 JUN 21 PY 1999 VL 82 IS 25 BP 5112 EP 5115 DI 10.1103/PhysRevLett.82.5112 PG 4 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300041 ER PT J AU Jahns, V Zehner, DM Watson, GM Gibbs, D AF Jahns, V Zehner, DM Watson, GM Gibbs, D TI Structure and phase behavior of the Ir(001) surface: X-ray scattering measurements SO SURFACE SCIENCE LA English DT Article DE iridium; roughening; single crystal surfaces; X-ray scattering; diffraction; and reflectivity ID ORIENTATIONAL EPITAXY; AU(001) SURFACE; HIGH-TEMPERATURE; AU(100) SURFACE; RECONSTRUCTION; GOLD; PLATINUM; PT(001); IR(100); IRIDIUM AB We present the results of X-ray scattering studies of the structure and phase behavior of the Ir(001) surface between room temperature and T = 2000 K. Two distinct phases have been identified. For temperatures above T = 1950 K, the Ir(001) surface is rough, similar to what has been observed for Pt(001) at elevated temperatures. Below about T = 1950 K, the surface reconstructs to farm a quasi-hexagonal unit cell, which is commensurate with the substrate lying beneath it. The measured X-ray intensities, both inplane and along the specular rod, are consistent with a buckled, (5 x 1) description of the structure, including a 15% expansion of the top layer spacing and an enhanced surface Debye-Waller factor. A detailed comparison is made of the phase behavior determined here for Ir(001) to that found earlier for Pt and Au(001). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. RP Gibbs, D (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 29 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 21 PY 1999 VL 430 IS 1-3 BP 55 EP 66 DI 10.1016/S0039-6028(99)00401-X PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 217GQ UT WOS:000081492000014 ER PT J AU Corradini, V Gavioli, L Mariani, C AF Corradini, V Gavioli, L Mariani, C TI Core-level photoemission study of 2D ordered Bi/Si(100) interfaces SO SURFACE SCIENCE LA English DT Article DE bismuth; metal-semiconductor interfaces; silicon; surface relaxation and reconstruction synchrotron radiation photoelectron spectroscopy ID SCANNING-TUNNELING-MICROSCOPY; SI(100) SURFACE; ELECTRONIC-STRUCTURE; SI(001) SURFACE; LOW-TEMPERATURE; BI; RECONSTRUCTIONS; BISMUTH; GROWTH; DIMERS AB A high resolution fore-level photoemission investigation of 2D ordered Bi layers grown on Si(100)-(2 x 1) is presented. We study the Si 2p and Bi 5d core-levels at room temperature as a function of coverage and in the reconstructed phases. The different Bi structural configurations around the monolayer coverage and in the (2 x n)-reconstructed phase are derived from the core-level lineshape evolution. By following the Fermi level pinning, the presence of Bi-induced occupied electronic states close to the Si mid-gap is suggested. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Modena, Dipartimento Fis, Ist Nazl Fis Mat, I-41100 Modena, Italy. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Mariani, C (reprint author), Univ Modena, Dipartimento Fis, Ist Nazl Fis Mat, Via G Campi 213-A, I-41100 Modena, Italy. RI Gavioli, Luca/G-5268-2010; mariani, carlo/L-7344-2013; OI Gavioli, Luca/0000-0003-2782-7414; Mariani, Carlo/0000-0002-7979-1700 NR 42 TC 7 Z9 7 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 21 PY 1999 VL 430 IS 1-3 BP 126 EP 136 DI 10.1016/S0039-6028(99)00426-4 PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 217GQ UT WOS:000081492000020 ER PT J AU Thundat, T Maya, L AF Thundat, T Maya, L TI Monitoring chemical and physical changes on sub-nanogram quantities of platinum dioxide SO SURFACE SCIENCE LA English DT Letter DE atomic force microscopy; chemical and physical changes; hydrogen reduction; microcantilevers; nanogram adsorbates; platinum oxide; surface topography; surface stress ID RESONATING MICROCANTILEVERS; MICROMECHANICAL SENSORS; CANTILEVERS AB We have measured in real-time the chemical reaction-induced weight loss and variation in physical and mechanical properties of sub-nanogram quantities of deposits utilizing the resonance response of microcantilevers. The hydrogen reduction of sub-nanogram quantities of alpha platinum oxide deposited on micromachined silicon cantilevers and resultant weight loss, as well as the kinetics of this process, were investigated. Comparison with theory suggests that this technique could be a powerful tool to measure physical and chemical changes occurring on sub-nanogram deposits. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Thundat, T (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 11 TC 19 Z9 19 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 21 PY 1999 VL 430 IS 1-3 BP L546 EP L552 DI 10.1016/S0039-6028(99)00422-7 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 217GQ UT WOS:000081492000006 ER PT J AU Wells, JD Moiseev, A Ormes, JF AF Wells, JD Moiseev, A Ormes, JF TI Illuminating dark matter and primordial black holes with interstellar antiprotons SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; elementary particles ID COSMIC-RAY ANTIPROTONS; GAMMA-RAYS; SOLAR MINIMUM; GALACTIC ANTIPROTONS; HALO; ANNIHILATIONS; MODULATION; PARTICLES; RADIATION; MASS AB Interstellar antiproton fluxes can arise from dark matter annihilating or decaying into quarks or gluons that subsequently fragment into antiprotons. Evaporation of primordial black holes can also produce a significant antiproton cosmic-ray flux. Since the background of secondary antiprotons from spallation has an interstellar energy spectrum that peaks at similar to 2 GeV and falls rapidly for energies below this, low-energy measurements of cosmic antiprotons are useful in the search for exotic antiproton sources. However, measurement of the flux near the Earth is challenged by significant uncertainties arising from the effects of the solar wind. We suggest evading this problem and more effectively probing dark matter signals by placing an antiproton spectrometer aboard an interstellar probe currently under discussion. We address the experimental challenges of a light, low-power-consuming detector, and present an initial design of such an instrument. This experimental effort could significantly increase our ability to detect, and have confidence in, a signal from exotic, nonstandard antiproton sources. Furthermore, solar modulation effects in the heliosphere could be better quantified and understood by comparing results to inverse modulated data derived from existing balloon and space-based detectors near the Earth. C1 CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wells, JD (reprint author), CERN, Div Theory, CH-1211 Geneva 23, Switzerland. NR 52 TC 12 Z9 12 U1 0 U2 0 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 JUN 20 PY 1999 VL 518 IS 2 BP 570 EP 575 DI 10.1086/307325 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211KA UT WOS:000081158700004 ER PT J AU Ryutov, D Drake, RP Kane, J Liang, E Remington, BA Wood-Vasey, WM AF Ryutov, D Drake, RP Kane, J Liang, E Remington, BA Wood-Vasey, WM TI Similarity criteria for the laboratory simulation of supernova hydrodynamics SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; instabilities; shock waves; supernova remnants; supernovae : general; supernovae : individual (SN 1987A) ID LARGE MAGELLANIC CLOUD; X-RAY-EMISSION; II SUPERNOVAE; SN 1987A; ELECTRON ACCELERATION; CIRCUMSTELLAR RING; NOVA LASER; MODEL; INSTABILITY; REMNANTS AB The conditions for validity and the limitations of experiments intended to simulate astrophysical hydrodynamics are discussed, with application to some ongoing experiments. For systems adequately described by the Euler equations, similarity criteria required for properly scaled experiments are identified. The conditions for the applicability of the Euler equations are formulated, based on the analysis of localization, heat conduction, viscosity, and radiation. Other considerations involved in such a scaling, including its limitations at small spatial scales, are discussed. The results are applied to experiments aimed at simulating three-dimensional hydrodynamics during supernova explosions and hydrodynamic instabilities in young supernova remnants. In addition, hydrodynamic situations with significant radiative effects are discussed. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Ryutov, D (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 43 TC 260 Z9 263 U1 2 U2 36 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 JUN 20 PY 1999 VL 518 IS 2 BP 821 EP 832 DI 10.1086/307293 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211KA UT WOS:000081158700026 ER PT J AU Basu, S Dappen, W Nayfonov, A AF Basu, S Dappen, W Nayfonov, A TI Helioseismic analysis of the hydrogen partition function in the solar interior SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; equation of state; Sun : interior; Sun : oscillations ID MEDIUM-L PROGRAM; VIRIAL EXPANSIONS; QUANTUM PLASMAS; 5-MINUTE OSCILLATION; STELLAR ENVELOPES; MODE FREQUENCIES; HELIUM DIFFUSION; CONVECTION ZONE; STATE; EQUATION AB The difference in the adiabatic gradient gamma(1) between inverted solar data and solar models is analyzed. To obtain deeper insight into the issues of plasma physics, the so-called intrinsic difference in gamma(1) is extracted, that is, the difference due to the change in the equation of state alone. Our method uses reference models based on two equations of state currently used in solar modeling, the Mihalas-Hummer-Dappen (MHD) equation of state and the OPAL equation of state (developed at Livermore). Solar oscillation frequencies from the SOI/MDI instrument on board the SOHO spacecraft during its first 144 days in operation are used. Our results confirm the existence of a subtle effect of the excited states in hydrogen that was previously studied only theoretically (Nayfonov & Dappen). The effect stems from an internal partition function of hydrogen, as is used in the MHD equation of state. Although it is a pure hydrogen effect, it takes place in somewhat deeper layers of the Sun, where more than 90% of hydrogen is ionized, and where the second ionization zone of helium is located. Therefore, the effect will have to be taken into account in reliable helioseismic determinations of the astrophysically relevant helium abundance of the solar convection zone. C1 Inst Adv Studies, Sch Nat Sci, Princeton, NJ 08540 USA. Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Aarhus Univ, Inst Phys & Astron, Theoret Astrophys Ctr, DK-8000 Aarhus, Denmark. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. RP Basu, S (reprint author), Inst Adv Studies, Sch Nat Sci, Princeton, NJ 08540 USA. OI Basu, Sarbani/0000-0002-6163-3472 NR 73 TC 49 Z9 49 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 JUN 20 PY 1999 VL 518 IS 2 BP 985 EP 993 DI 10.1086/307312 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211KA UT WOS:000081158700042 ER PT J AU Gu, MF Kahn, SM Savin, DW Beiersdorfer, P Brown, GV Liedahl, DA Reed, KJ Bhalla, CP Grabbe, SR AF Gu, MF Kahn, SM Savin, DW Beiersdorfer, P Brown, GV Liedahl, DA Reed, KJ Bhalla, CP Grabbe, SR TI Laboratory measurements of Fe XXIV line emission: 3 -> 2 transitions near excitation threshold SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; line : formation; methods : laboratory; X-rays : general ID X-RAY SPECTROMETER; BEAM ION-TRAP; DIELECTRONIC-RECOMBINATION; CROSS-SECTIONS; ELECTRON-BEAM; RADIATIVE RECOMBINATION; POLARIZATION AB Using the Electron Beam Ion Trap facility at Lawrence Livermore National Laboratory, we have measured relative cross sections for Fe XXIV line emission at electron energies between 0.7 and 3.0 keV. The measurements include line formation by direct electron impact excitation (DE), radiative cascades, resonant excitation (RE), and dielectronic recombination (DR) satellites with captured electrons in n greater than or equal to 5 levels. Good agreement with R-matrix and distorted wave calculations is found. In collisionally ionized plasmas, at temperatures near where the ion abundance peaks (kT(e) similar to 1.7 keV), the RE contributions are found to be less than or similar to 5% of the line emission, while the DR satellites contribute less than or similar to 10%. While good agreement with state-of-the-art atomic physics calculations is found, there is less good agreement with existing spectral synthesis codes in common astrophysical use. For the Fe XXIV 3p(3/2) --> 2s(1/2), 3p(1/2) --> 2s(1/2), and 3d(5/2) --> 2p(3/2) transitions, the synthesis code MEKAL underestimates the emissivity in coronal equilibrium by similar to 20% at temperatures near where the ion abundance peaks. In situations where the ionization balance is not solely determined by the electron temperature, RE and DR satellites may contribute a considerable fraction of the line emission. C1 Columbia Univ, Dept Phys, New York, NY 10027 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. RP Gu, MF (reprint author), Columbia Univ, Dept Phys, 538 W 120th St, New York, NY 10027 USA. RI Savin, Daniel/B-9576-2012 OI Savin, Daniel/0000-0002-1111-6610 NR 31 TC 33 Z9 35 U1 2 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1999 VL 518 IS 2 BP 1002 EP 1009 DI 10.1086/307326 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211KA UT WOS:000081158700044 ER PT J AU Fenimore, EE Ramirez-Ruiz, E Wu, BB AF Fenimore, EE Ramirez-Ruiz, E Wu, BB TI GRB 990123: Evidence that the gamma rays come from a central engine SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID BURSTS; AFTERGLOW; MODELS AB GRB 990123 was a long, complex gamma-ray burst with an optical transient that started early within the gamma-ray phase. The peak and power-law decay of the early optical emission strongly indicate the presence of a decelerating relativistic shell during that phase. Prior to this burst, it was not known if the shell decelerated during the burst, so an external shock origin for the gamma rays was still possible. If the gamma rays are produced in the external shock, then the pulse widths should reflect the observed deceleration of the shell and increase by a factor between 1.25 and 2.3, depending on the angular extent of the shell. We analyze the fine time structure observed in the gamma-ray data from BATSE and determine that the width of the peaks does not increase as expected for a decelerating shell; the later pulses are only 1.034 +/- 0.035 longer than the earlier pulses. The lack of pulse width evolution eliminates the only remaining kinematically acceptable external shock explanation for the gamma-ray phase and, thus, the gamma rays must originate at a central engine. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Nacl Autonoma Mexico, Fac Ciencias, Mexico City 04510, DF, Mexico. Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. RP Fenimore, EE (reprint author), Los Alamos Natl Lab, MS D436, Los Alamos, NM 87545 USA. NR 33 TC 37 Z9 41 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 JUN 20 PY 1999 VL 518 IS 2 BP L73 EP L76 DI 10.1086/312075 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211MA UT WOS:000081163800004 ER PT J AU van Breugel, W De Breuck, C Stanford, SA Stern, D Rottgering, H Miley, G AF van Breugel, W De Breuck, C Stanford, SA Stern, D Rottgering, H Miley, G TI A radio galaxy at z=5.19 SO ASTROPHYSICAL JOURNAL LA English DT Article DE early universe; galaxies : active; galaxies : distances and redshifts galaxies : formation; galaxies : individual (TN J0924-2201) ID REDSHIFT; EMISSION; SAMPLE; NUCLEI; Z=4.25; DUST AB We report the discovery of the most distant known active galactic nucleus, the radio galaxy TN J0924-2201 at z = 5.19. The radio source was selected from a new sample of ultrasteep spectrum sources, has an extreme radio spectral index alpha(365 MHz)(1.4 GHz) = -1.63, and is identified at near-IR wavelengths with a very faint, K = 21.3 +/- 0.3 object. Spectroscopic observations show a single emission line at lambda similar to 7530 Angstrom, which we identify as Ly alpha. The K-band image, sampling rest-frame U band, shows a multicomponent, radio-aligned morphology, which is typical of lower-redshift radio galaxies. TN J0924-2201 extends the near-IR Hubble, or K-z, relation for powerful radio galaxies to z > 5 and is consistent with models of massive galaxies forming at even higher redshifts. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP van Breugel, W (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. EM wil@igpp.llnl.gov; debreuck@strw.leidenuniv.nl; adam@igpp.llnl.gov; dan@bigz.berkeley.edu; rottgeri@strw.leidenuniv.nl; miley@strw.leidenuniv.nl OI De Breuck, Carlos/0000-0002-6637-3315 NR 29 TC 92 Z9 93 U1 0 U2 1 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 JUN 20 PY 1999 VL 518 IS 2 BP L61 EP L64 DI 10.1086/312080 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211MA UT WOS:000081163800001 ER PT J AU Matsubara, I Paranthaman, M Singhal, A Vallet, C Lee, DF Martin, PM Hunt, RD Feenstra, R Yang, CY Babcock, SE AF Matsubara, I Paranthaman, M Singhal, A Vallet, C Lee, DF Martin, PM Hunt, RD Feenstra, R Yang, CY Babcock, SE TI Preparation of textured YBCO films using all-iodide precursors SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article DE Y123 films; metal iodides; solution process; textured films ID DIPPING-PYROLYSIS PROCESS; CRITICAL-CURRENT DENSITY; SOL-GEL SYNTHESIS; THIN-FILMS; SUPERCONDUCTING TAPES; EPITAXIAL-GROWTH; BUFFER LAYERS; SRTIO3(100); DEPOSITION; LAALO3 AB We developed an all-iodide precursor approach to grow epitaxial YBa2Cu3O7-y (YBCO) films on single crystal substrates. The respective metal iodides were used as the starting materials. Initially, yttrium and barium iodides were dissolved in 2-methoxyethanol, whereas copper iodide was dissolved in ammonium iodide/dimethylformamide solution. The solutions were mixed together and concentrated to give a 2.5-M total cation precursor solution. The precursor solutions were spin coated on SrTiO3 (100) substrates and heat-treated at 800-830 degrees C in 300 ppm oxygen atmospheres. X-ray diffraction (XRD) results from the theta-2theta (theta-2 theta) scan, omega (omega) and phi (phi) scans for the films revealed a (100) cubic texture. The full-width-at-half-maximum (FWHM) values for YBCO (105) and YBCO (005) were 1.3 degrees (in-plane epitaxy, Delta phi) and 0.42 degrees (out-of-plane epitaxy, Delta omega), respectively. The YBCO films had a T-c of 90.3 K. The measured transport J(c), critical current density was 1.3 x 10(5) A/cm(2) at 77 K and self-field. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Matsubara, I (reprint author), Osaka Natl Res Inst, 1-8-31 Midorigaoka, Ikeda, Osaka 563, Japan. RI Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 20 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 EI 1873-2143 J9 PHYSICA C JI Physica C PD JUN 20 PY 1999 VL 319 IS 3-4 BP 127 EP 132 DI 10.1016/S0921-4534(99)00303-2 PG 6 WC Physics, Applied SC Physics GA 217VK UT WOS:000081519400001 ER PT J AU Rybaltchenko, LF Jansen, AGM Wyder, P Tjutrina, LV Canfield, PC Tomy, CV Paul, DM AF Rybaltchenko, LF Jansen, AGM Wyder, P Tjutrina, LV Canfield, PC Tomy, CV Paul, DM TI Point-contact study of the magnetic superconductor HoNi2B2C SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article DE magnetic superconductors; borocarbides; point contacts; order parameter ID ANDREEV-REFLECTION; ORDER; MAGNETORESISTANCE AB Point contacts (PC) based on the magnetic superconductor HoNi2B2C with a superconducting onset temperature T-c similar to 8.5 K have been investigated in order to determine the temperature and magnetic field dependences of the superconducting order parameter. The temperature dependence of the order parameter satisfies the Bardeen-Cooper-Schrieffer (BCS) theory only below the BCS transition temperature T-c(BCS) = 55-5.8 K, which exceeds slightly the Neel temperature T-N similar to 5.0 K. At higher temperatures, above T-N, the PC spectra dV/dI(V) indicate an anomalous, most likely gapless, superconducting state. At magnetic fields well below H-c2, a considerable increase (similar to 30%) in the characteristic voltage of the gap-related structure in the PC spectra is observed which points to an improved spin alignment with a decreasing influence of the pair breaking in modest fields. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Max Planck Inst Festkorperforsch, Grenoble High Magnet Field Lab, F-38042 Grenoble 9, France. CNRS, F-38042 Grenoble 9, France. Ukrainian Acad Sci, B Verkin Inst Low Temp Phys & Engn, UA-310164 Kharkov, Ukraine. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RP Jansen, AGM (reprint author), Max Planck Inst Festkorperforsch, Grenoble High Magnet Field Lab, BP 166, F-38042 Grenoble 9, France. EM ljansen@labs.polycnrs-gr.fr RI Canfield, Paul/H-2698-2014 NR 23 TC 15 Z9 15 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 EI 1873-2143 J9 PHYSICA C JI Physica C PD JUN 20 PY 1999 VL 319 IS 3-4 BP 189 EP 196 DI 10.1016/S0921-4534(99)00282-8 PG 8 WC Physics, Applied SC Physics GA 217VK UT WOS:000081519400009 ER PT J AU Eberling, JL Bankiewicz, KS Pivirotto, P Bringas, J Chen, K Nowotnik, DP Steiner, JP Budinger, TF Jagust, WJ AF Eberling, JL Bankiewicz, KS Pivirotto, P Bringas, J Chen, K Nowotnik, DP Steiner, JP Budinger, TF Jagust, WJ TI Dopamine transporter loss and clinical changes in MPTP-lesioned primates SO BRAIN RESEARCH LA English DT Article DE Parkinson's disease; MPTP; monkey; single photon emission computed tomography; dopamine transporter; beta-CIT ID I-123 BETA-CIT; POSITRON EMISSION TOMOGRAPHY; COCAINE RECOGNITION SITES; MONOAMINE REUPTAKE SITES; H-3 PAROXETINE BINDING; SEROTONIN UPTAKE SITES; PARKINSONS-DISEASE; HUMAN-BRAIN; SPECT; KINETICS AB Single photon emission computed tomography (SPECT) and the dopamine (DA) transporter tracer, 2 beta-carboxymethoxy-3 beta-(4-iodophenyl)tropane ([I-123]beta-CIT), were used to determine DA transporter density in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys with varying degrees of parkinsonism. The clinical stage of parkinsonism corresponded to SPECT measures of striatal DA transporter density suggesting that more severe parkinsonism was associated with a greater degree of dopaminergic terminal degeneration. These findings are similar to those reported earlier using positron emission tomography (PET) and the DA metabolism tracer, 6-[F-18]fluoro-L-m-tyrosine (FMT), indicating that both are good methods for evaluating nigrostriatal degeneration in MPTP primate models. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. NINDS, NIH, Bethesda, MD 20892 USA. CroMed Biosci, Orinda, CA USA. Guilford Pharmaceut, Baltimore, MD USA. Martinez VA Med Ctr, Dept Neurol, Martinez, CA USA. Univ Calif Davis, Davis, CA 95616 USA. RP Eberling, JL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 25 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-8993 J9 BRAIN RES JI Brain Res. PD JUN 19 PY 1999 VL 832 IS 1-2 BP 184 EP 187 DI 10.1016/S0006-8993(99)01491-2 PG 4 WC Neurosciences SC Neurosciences & Neurology GA 209UG UT WOS:000081066800024 PM 10375668 ER PT J AU Perrin, RM DeRocher, AE Bar-Peled, M Zeng, WQ Norambuena, L Orellana, A Raikhel, NV Keegstra, K AF Perrin, RM DeRocher, AE Bar-Peled, M Zeng, WQ Norambuena, L Orellana, A Raikhel, NV Keegstra, K TI Xyloglucan fucosyltransferase, an enzyme involved in plant cell wall biosynthesis SO SCIENCE LA English DT Article ID COMPLEX POLYSACCHARIDES; GOLGI-APPARATUS; ARABIDOPSIS; CELLULOSE; GLYCOSYLTRANSFERASES; OLIGOSACCHARIDES; GLYCOPROTEINS; FUCOSYLATION; LOCALIZATION; SIMULATIONS AB Cell walls are crucial for development, signal transduction, and disease resistance in plants. Cell walls are made of cellulose, hemicelluloses, and pectins. Xyloglucan (XG), the principal load-bearing hemicellulose of dicotyledonous plants. has a terminal fucosyl residue. A 60-kilodalton fucosyltransferase (FTase) that adds this residue was purified from pea epicotyls. Peptide sequence information from the pea FTase allowed the cloning of a homologous gene, AtFT1, from Arabidopsis. Antibodies raised against recombinant AtFTase immunoprecipitate FTase enzyme activity from solubilized Arabidopsis membrane proteins, and AtFT1 expressed in mammalian COS cells results in the presence of XG FTase activity in these cells. C1 Michigan State Univ, US DOE, Plant Res Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Bot & Plant Pathol, E Lansing, MI 48824 USA. Michigan State Univ, Dept Biochem, E Lansing, MI 48824 USA. Michigan State Univ, Cell & Mol Biol Program, E Lansing, MI 48824 USA. Univ Chile, Fac Sci, Dept Biol, Santiago, Chile. RP Keegstra, K (reprint author), Michigan State Univ, US DOE, Plant Res Lab, E Lansing, MI 48824 USA. RI Orellana, Ariel/E-2166-2014; Norambuena, Lorena/I-1248-2013 OI Orellana, Ariel/0000-0002-9243-808X; Norambuena, Lorena/0000-0002-6031-2394 NR 26 TC 168 Z9 179 U1 1 U2 21 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 JUN 18 PY 1999 VL 284 IS 5422 BP 1976 EP 1979 DI 10.1126/science.284.5422.1976 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 207JA UT WOS:000080932700043 PM 10373113 ER PT J AU Dixon, DA Feller, D Sandrone, G AF Dixon, DA Feller, D Sandrone, G TI Heats of formation of simple perfluorinated carbon compounds SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR WAVE-FUNCTIONS; CONFIGURATION-INTERACTION CALCULATIONS; GAUSSIAN-BASIS SETS; BENCHMARK CALCULATIONS; ATOMIZATION ENERGIES; SYSTEMATIC SEQUENCES; TRIPLE EXCITATIONS; DIATOMIC HYDRIDES; PI-BOND; IONIZATION AB The heats of formation of CF(3), its cation and anion, CF(4), C(2)F(4), and :CFCF(3) have been calculated at high levels of ab initio molecular orbital theory. Geometries and frequencies were determined, in general, with second-order perturbation theory. Total energies based on coupled cluster calculations with perturbative triples were determined with basis sets up through augmented quadruple-zeta in quality and were subsequently extrapolated to the complete one-particle basis set limit, so as to further reduce the basis set truncation error. Due to its importance as a standard, CF(4) was studied with even larger basis sets. Additional improvements in the atomization energy were achieved by applying corrections due to core/valence correlation, scalar relativistic, and atomic spin-orbit effects. Zero-point energies were based on the experimental fundamentals, when available, and harmonic frequencies obtained from MP2/cc-pVTZ calculations. Missing frequencies for :CFCF(3) were calculated at the MP2/DZP level. The calculated heats of formation (kcal/mol) are as follows: Delta H(f)(CF(4)) = -221.8 +/- 1.1 vs -221.6 +/- 0.3 (expt); Delta H(f)(CF(3)) = -111.9 +/- 1.0 vs -111.7 +/- 1.0 (expt); Delta H(f)(CF(3)(+)) = 98.0 +/- 1.2 vs 99.8 +/- 2.8 (expt); Delta H(f)(CF(3)(-)) = -151.9 +/- 0.7 vs -154.9 +/- 1.0 (expt); Delta H(f)(C(2)F(4)) = -159.8 +/- 1.5 vs -156.6 +/- 0.7 (expt); and Delta H(f)(:CFCF(3)) = -122.6 +/- 1.5, all at 0 K. These values are used to calculate a variety of bond energies and molecular energetics. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dixon, DA (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 68 TC 130 Z9 130 U1 0 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 JUN 17 PY 1999 VL 103 IS 24 BP 4744 EP 4751 DI 10.1021/jp990425b PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 211GM UT WOS:000081152600022 ER PT J AU Webb, EB Grest, GS Mondello, M AF Webb, EB Grest, GS Mondello, M TI Intracrystalline diffusion of linear and branched alkanes in the zeolites TON, EUO, and MFI SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; LONG N-ALKANES; SILICALITE; HYDROCARBONS; ADSORPTION; PARAFFINS; SORPTION; METHANE; BUTANE; DIFFUSIVITIES AB Diffusion constants D and activation energies for diffusion E-a were obtained for linear and branched alkanes inside the zeolites TON, EUO, and MFI via molecular dynamics simulations. Molecules with carbon numbers in the range n = 7-30 were studied in the dilute limit. The zeolites used have channels formed by 10-member silicate rings, but the diameter and connectivity of the channels differ between zeolites. Because the zeolites' channel features are different, it was observed that the influences of channel. structure on molecular transport, or lattice effects, were also different between zeolites. For linear alkanes in the relatively uniform channels of TON, lattice effects were least pronounced so the highest values for D were observed and D scaled as 1/n. Furthermore, E-a approximate to 1 kcal/mol at small n and decreased to nearly zero for large n. The features of the channels in EUO and MFI were such that lattice effects were observed for linear alkanes. Generally, D was lower than in TON and decreased faster than 1/n; in EUO, E-a increased with n, while in MFI the dependence of E-a on n was anisotropic. Monomethyl-branched alkanes diffused slower than their linear counterparts. Branched molecules are effectively bulkier making interactions with the channel walls more influential. Lattice effects were observed for branched molecules in all the zeolites; especially in the trends of D with branch position. C1 Exxon Res & Engn Co, Corp Res Sci Labs, Annandale, NJ 08801 USA. RP Webb, EB (reprint author), Sandia Natl Labs, POB 5800,MS 1411, Albuquerque, NM 87185 USA. NR 46 TC 45 Z9 46 U1 1 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 JUN 17 PY 1999 VL 103 IS 24 BP 4949 EP 4959 DI 10.1021/jp9845266 PG 11 WC Chemistry, Physical SC Chemistry GA 211FV UT WOS:000081150900004 ER PT J AU Tang, J Utschig, LM Poluektov, O Thurnauer, MC AF Tang, J Utschig, LM Poluektov, O Thurnauer, MC TI Transient W-band EPR study of sequential electron transfer in photosynthetic bacterial reaction centers SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID RHODOBACTER-SPHAEROIDES R-26; SUBSTITUTED REACTION CENTERS; HIGH-FIELD EPR; RADICAL PAIRS; SPIN POLARIZATION; RHODOPSEUDOMONAS-SPHAEROIDES; DIFFERENT QUINONES; PRIMARY DONOR; G-TENSOR; 95 GHZ AB Electron-spin polarized (ESP) EPR spectra at W-band (95 GHz) were obtained for deuterated Fe-removed/Zn-substituted photosynthetic bacterial reaction centers (RCs) to investigate the influence of the rate of charge separation on the observed P(+)Q(A)(-) charge separated state. Temperature dependent ESP EPR spectra for kinetically characterized Zn-substituted RCs from Rb. sphaeroides R-26 having different rates (kh) of the electron transfer from the bacteriopheophytin to the quinone acceptor were obtained. The Zn-RCs exhibited either the native "fast" (200 ps)(-1) k(Q) or a "slow" (3-6 ns)(-1) k(Q) at 298 K as determined from transient optical measurements. Sequential electron-transfer polarization modeling of the polarized W-band EPR spectra obtained with these samples was used to address the reason for the differences in the electron-transfer rates, Herein, we report the ka rate constant, the temperature dependence of k(Q), and the reorganization energy for the P(+)H(-)Q(A) and P(+)HQ(A)(-) electron-transfer step determined from SETP modeling of the experimental spectra. The reorganization energy for the electron-transfer process between P(+)H(-)Q(A) and P(+)HQ(A)(-), and not structural changes in the donor or acceptor, was found to be the dominant factor that is altered during Fe-removal procedures. C1 Argonne Natl Lab, Chem Div D200, Argonne, IL 60439 USA. RP Thurnauer, MC (reprint author), Argonne Natl Lab, Chem Div D200, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Tang, Jau/D-8382-2012 OI Tang, Jau/0000-0003-2078-1513 NR 40 TC 27 Z9 32 U1 2 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 JUN 17 PY 1999 VL 103 IS 24 BP 5145 EP 5150 DI 10.1021/jp990236t PG 6 WC Chemistry, Physical SC Chemistry GA 211FV UT WOS:000081150900029 ER PT J AU Keum, YY Nierste, U Sanda, AI AF Keum, YY Nierste, U Sanda, AI TI A short look at epsilon '/epsilon SO PHYSICS LETTERS B LA English DT Article DE violation, CP; interpretation of experiments; quark, mass; new interaction, search for; K0 ID HADRONIC MATRIX-ELEMENTS; TO-LEADING ORDER; ANOMALOUS DIMENSION MATRIX; WEAK NONLEPTONIC DECAYS; NEUTRAL KAON SYSTEM; DIRECT CP VIOLATION; LIGHT-QUARK MASSES; LARGE-N LIMIT; QCD CORRECTIONS; K->PI-PI DECAYS AB We analyze the theoretical implications of the new KTeV measurement of direct CP-violation in K --> pi pi decays. The result is found consistent with the Standard Model for low values of the strange quark mass m(s). If the hadronic parameters B-6((1/2)) and B-8((3/2)) satisfy 2B(6)((1/2)) - B-8((3/2)) less than or equal to 2, as suggested by lattice and 1/N-c calculations, we find an upper bound of 110MeV for m(s)(2 GeV). We parametrize potential new physics contributions to epsilon' / epsilon and illustrate their correlation with upper bounds an m(s). Finally we discuss a non-perturbative mechanism, which is not contained in the existing calculations of B-6((1/2)). This mechanism enhances B-6((1/2)) and thereby leads to a better understanding of the Delta I = 1/2 rule and the high measured value of Re(epsilon' / epsilon). (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 KEK, Theory Grp, Ibaraki, Osaka 3050801, Japan. Fermi Natl Accelerator Lab, Theory Div MS106, Batavia, IL 60510 USA. Nagoya Univ, Dept Phys, Nagoya, Aichi 446, Japan. RP Keum, YY (reprint author), KEK, Theory Grp, Ibaraki, Osaka 3050801, Japan. NR 42 TC 34 Z9 34 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 JUN 17 PY 1999 VL 457 IS 1-3 BP 157 EP 162 DI 10.1016/S0370-2693(99)00523-7 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 211PZ UT WOS:000081170500022 ER PT J AU Bigi, I Uraltsev, N AF Bigi, I Uraltsev, N TI Pauli interference in the 't Hooft model: heavy quark expansion and quark-hadron duality SO PHYSICS LETTERS B LA English DT Article ID INCLUSIVE WEAK DECAYS; RESONANCE PHYSICS; CHARM DECAYS; QCD; CONFINEMENT; MESONS; BEAUTY AB Pauli Interference in decays of heavy flavor mesons, a genuinely nonleptonic nonperturbative effect, is considered in the 't Hooft model. Analytic summation of the exclusive decay widths yields the same expression as obtained in the OPE-based approach. Threshold-related violations of local duality in PI are found to be suppressed. A novel case is identified where the OPE effect is completely saturated by a single final state. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Notre Dame du Lac, Dept Phys, Notre Dame, IN 46556 USA. Jefferson Lab, Newport News, VA 23606 USA. Petersburg Nucl Phys Inst, St Petersburg 188350, Russia. RP Univ Notre Dame du Lac, Dept Phys, Notre Dame, IN 46556 USA. EM bigi@undhep.hep.nd.edu; uraltsev@undhep.hep.nd.edu NR 30 TC 10 Z9 10 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 JUN 17 PY 1999 VL 457 IS 1-3 BP 163 EP 169 DI 10.1016/S0370-2693(99)00540-7 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 211PZ UT WOS:000081170500023 ER PT J AU Alessandrello, A Beeman, JW Brofferio, C Cremonesi, O Fiorini, E Giuliani, A Haller, EE Margesin, B Monfardini, A Nucciotti, A Pavan, M Pessina, G Pignatel, G Previtali, E Zanotti, L Zen, M AF Alessandrello, A Beeman, JW Brofferio, C Cremonesi, O Fiorini, E Giuliani, A Haller, EE Margesin, B Monfardini, A Nucciotti, A Pavan, M Pessina, G Pignatel, G Previtali, E Zanotti, L Zen, M TI Bolometric measurements of beta decay spectra of Re-187 with crystals of silver perrhenate SO PHYSICS LETTERS B LA English DT Article DE beta decay; antineutrino mass; geochronology ID RARE DECAYS; SYSTEMATICS; DETECTORS AB Crystals of silver perrhenate were used for the first time in the bolometric measurement of the spectrum of Re-187 with the aim of determining the electron antineutrino mass. The temperature rise was measured by means of neutron transmutation doped germanium and P-implanted silicon thermistors. The energy scale was calibrated using the K lines of Mn and the fluorescence L lines of Sn. Bolometers made from crystals of masses ranging from similar to 250 to similar to 500 mu g were run with FWHM resolutions on the Sn lines ranging from 25 to 60 eV. The end point of the spectrum was located at 2460 +/- 5(stat) +/- 10(syst) eV. The measured half lifetime was 43 +/- 4(stat) +/- 3(syst) Gyr, which is in good agreement with the values obtained with mass spectroscopy from the build-up of Os-187 in rhenium samples. The sensitivity of the measurement on a non-zero neutrino mass achievable with these bolometers is discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Trent, Dipartimento Ingn Mat, I-38050 Povo, TN, Italy. IRST, I-38050 Povo, TN, Italy. RP Fiorini, E (reprint author), Via Celoria 16, I-20133 Milan, Italy. RI Nucciotti, Angelo/I-8888-2012; Margesin, Benno/K-5826-2015; OI Nucciotti, Angelo/0000-0002-8458-1556; Margesin, Benno/0000-0002-1120-3968; Pessina, Gianluigi Ezio/0000-0003-3700-9757 NR 38 TC 32 Z9 32 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 17 PY 1999 VL 457 IS 1-3 BP 253 EP 260 DI 10.1016/S0370-2693(99)00519-5 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 211PZ UT WOS:000081170500034 ER PT J AU Loy, DA Carpenter, JP Alam, TM Shaltout, R Dorhout, PK Greaves, J Small, JH Shea, KJ AF Loy, DA Carpenter, JP Alam, TM Shaltout, R Dorhout, PK Greaves, J Small, JH Shea, KJ TI Cyclization phenomena in the sol-gel polymerization of alpha,omega-bis(triethoxysilyl) alkanes and incorporation of the cyclic structures into network silsesquioxane polymers SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID POLYHEDRAL OLIGOSILSESQUIOXANES; CONDENSATION; HYDROLYSIS; POLYCONDENSATION; PRECURSORS; OLIGOMERS AB Intramolecular cyclizations during acid-catalyzed sol-gel polymerizations of alpha,omega-bis(triethoxysilyl)-alkanes substantially lengthen gel times for monomers with ethylene (1), propylene (2), and butylene (3) bridging groups. These cyclization reactions were found, using mass spectrometry and Si-29 NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six- and seven-membered disilsesquioxane rings. 1,2-Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic dimer (5) that is composed of two annelated seven-membered rings. Under the same conditions, 1,3-bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and Z-1,4-bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six- and seven-membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dimers 8, 9, and 12. With NaOH as polymerization catalyst, these cyclic silsesquioxanes readily reacted to afford gels that were shown by CP MAS Si-29 NMR and infrared spectroscopies to retain some cyclic structures. Comparison of the porosity and microstructure of xerogels prepared from the cyclic monomers 6 and 7 with those of gels prepared directly from their acyclic precursors 2 and 3 indicates that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species cannot be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels. C1 Sandia Natl Labs, Catalysts Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Aging & Reliabil Bulk Mat Dept, Albuquerque, NM 87185 USA. Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Calif Los Alamos Natl Lab, Polymers & Coatings Grp, Los Alamos, NM 87545 USA. RP Loy, DA (reprint author), Sandia Natl Labs, Catalysts Dept, POB 5800, Albuquerque, NM 87185 USA. RI Loy, Douglas/D-4847-2009 OI Loy, Douglas/0000-0001-7635-9958 NR 44 TC 60 Z9 60 U1 2 U2 25 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 JUN 16 PY 1999 VL 121 IS 23 BP 5413 EP 5425 DI 10.1021/ja982751v PG 13 WC Chemistry, Multidisciplinary SC Chemistry GA 208RU UT WOS:000081006000008 ER PT J AU Mahadevan, V DuBois, JL Hedman, B Hodgson, KO Stack, TDP AF Mahadevan, V DuBois, JL Hedman, B Hodgson, KO Stack, TDP TI Exogenous substrate reactivity with a [Cu(III)(2)O-2](2+) core: Structural implications SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID C-H BOND; COPPER-COMPLEXES; DIOXYGEN; OXIDATION; HYDROXYLATION; INTERMEDIATE; ACTIVATION; EFFICIENT; REDUCTION; ALCOHOLS C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. RP Hedman, B (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. NR 24 TC 112 Z9 112 U1 0 U2 8 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 JUN 16 PY 1999 VL 121 IS 23 BP 5583 EP 5584 DI 10.1021/ja983635v PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 208RU UT WOS:000081006000031 ER PT J AU Peters, RG Warner, BP Burns, CJ AF Peters, RG Warner, BP Burns, CJ TI The catalytic reduction of azides and hydrazines using high-valent organouranium complexes SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ORGANOIMIDO; URANIUM C1 Los Alamos Natl Lab, Chem & Environm Res & Dev Grp, Los Alamos, NM 87545 USA. RP Burns, CJ (reprint author), Los Alamos Natl Lab, Chem & Environm Res & Dev Grp, CST-18, Los Alamos, NM 87545 USA. EM cjb@lanl.gov NR 13 TC 60 Z9 60 U1 0 U2 11 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 JUN 16 PY 1999 VL 121 IS 23 BP 5585 EP 5586 DI 10.1021/ja9844581 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 208RU UT WOS:000081006000032 ER PT J AU Lipschutz, ME Wolf, SF Hanchar, JM Culp, FB AF Lipschutz, ME Wolf, SF Hanchar, JM Culp, FB TI Geochemical and cosmochemical materials SO ANALYTICAL CHEMISTRY LA English DT Review ID PLASMA-MASS SPECTROMETRY; RARE-EARTH ELEMENTS; NEUTRON-ACTIVATION ANALYSIS; ATOMIC-ABSORPTION SPECTROMETRY; ABLATION ICP-MS; CERTIFIED REFERENCE MATERIALS; MARTIAN METEORITE ALH84001; ENERGY-LOSS SPECTROSCOPY; PLATINUM-GROUP ELEMENTS; GAMMA-RAY SPECTROMETER C1 Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. RP Lipschutz, ME (reprint author), Purdue Univ, Dept Chem, BRWN-WTHR Bldg, W Lafayette, IN 47907 USA. NR 294 TC 10 Z9 10 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 JUN 15 PY 1999 VL 71 IS 12 BP 1R EP 20R PG 20 WC Chemistry, Analytical SC Chemistry GA 206XW UT WOS:000080906600001 PM 10384779 ER PT J AU Workman, J Veltkamp, DJ Doherty, S Anderson, BB Creasy, KE Koch, M Tatera, JF Robinson, AL Bond, L Burgess, LW Bokerman, GN Ullman, AH Darsey, GP Mozayeni, F Bamberger, JA Greenwood, MS AF Workman, J Veltkamp, DJ Doherty, S Anderson, BB Creasy, KE Koch, M Tatera, JF Robinson, AL Bond, L Burgess, LW Bokerman, GN Ullman, AH Darsey, GP Mozayeni, F Bamberger, JA Greenwood, MS TI Process analytical chemistry SO ANALYTICAL CHEMISTRY LA English DT Review ID NEAR-INFRARED SPECTROSCOPY; VOLATILE ORGANIC-COMPOUNDS; INLET MASS-SPECTROMETRY; FLOW-INJECTION ANALYSIS; PARTIAL LEAST-SQUARES; SOLID-PHASE EXTRACTION; FIBEROPTIC RAMAN-SPECTROSCOPY; SUPERCRITICAL-FLUID EXTRACTION; CAPILLARY GAS-CHROMATOGRAPHY; FT-IR SPECTROSCOPY C1 Kimberly Clark Inc, Analyt Sci & Technol, Neenah, WI 54956 USA. Univ Washington, Ctr Proc Analyt Chem, Seattle, WA 98195 USA. Monsanto Co Searle, Chem Sci Grp, Skokie, IL 60077 USA. Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. Allied Signal Inc, Online Instrumentat Skill Ctr, Morristown, NJ 07962 USA. Dow Corning Corp, Proc Anal Expertise Ctr, Carrollton, KY 42701 USA. Pacific NW Lab, Richland, WA 99352 USA. Dow Corning Corp, Analyt & Testing Technol Ctr, Midland, MI 48686 USA. Procter & Gamble Co, Cincinnati, OH 43224 USA. Akzo Nobel Chem Inc, Analyt Dept, Dobbs Ferry, NY 10522 USA. RP Kimberly Clark Inc, Analyt Sci & Technol, Neenah, WI 54956 USA. NR 1246 TC 59 Z9 59 U1 0 U2 23 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD JUN 15 PY 1999 VL 71 IS 12 BP 121R EP 180R PG 60 WC Chemistry, Analytical SC Chemistry GA 206XW UT WOS:000080906600007 ER PT J AU Clement, RE Yang, PW Koester, CJ AF Clement, RE Yang, PW Koester, CJ TI Environmental analysis SO ANALYTICAL CHEMISTRY LA English DT Review ID PLASMA-MASS SPECTROMETRY; ATOMIC-ABSORPTION SPECTROMETRY; SOLID-PHASE MICROEXTRACTION; SUPERCRITICAL-FLUID EXTRACTION; VOLATILE ORGANIC-COMPOUNDS; POLYCYCLIC AROMATIC-HYDROCARBONS; PERFORMANCE LIQUID-CHROMATOGRAPHY; PRESSURE CHEMICAL-IONIZATION; CERTIFIED REFERENCE MATERIALS; X-RAY-FLUORESCENCE C1 Ontario Minist Environm, Lab Serv Branch, Etobicoke, ON M9P 3V6, Canada. Lawrence Livermore Natl Lab, Analyt Sci Div, Livermore, CA 94551 USA. RP Clement, RE (reprint author), Ontario Minist Environm, Lab Serv Branch, 125 Resources Rd, Etobicoke, ON M9P 3V6, Canada. NR 950 TC 20 Z9 20 U1 2 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD JUN 15 PY 1999 VL 71 IS 12 BP 257R EP 292R PG 36 WC Chemistry, Analytical SC Chemistry GA 206XW UT WOS:000080906600011 PM 10384786 ER PT J AU Fukui, K Sumpter, BG Runge, K Kung, CY Barnes, MD Noid, DW AF Fukui, K Sumpter, BG Runge, K Kung, CY Barnes, MD Noid, DW TI Collision dynamics and surface wetting of nano-scale polymer particles on substrates SO CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; CRYSTALLINE POLYETHYLENE; SIMULATION; CHAIN; NUCLEATION; DROPLETS; COLLAPSE AB Classical trajectory calculations are used to study collisions of nano-scale polyethylene (PE) particles on Si, C, and Al surfaces in a vacuum. The PE particles generated with up to 12000 atoms have been propagated up to 100 ps for those surfaces to investigate the self-organization of polymer particles (mechanical memory) via collisions. It is shown that particles with the initial velocity greater than 8 Angstrom/ps lose some chains while spreading on (coating) the surfaces during impact. In the simulation, the nano-ecale PE particles with the initial velocity less than 5 Angstrom/ps can self-organize back to their original spherical shape and do not show deformation of the shape. The results suggest that the experimentally observed deformation of a polymer particle on a substrate is due mainly to the surface interaction between the polymer particle and the substrate (surface wetting) and not to the collision. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Fukui, K (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 41 TC 14 Z9 14 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 15 PY 1999 VL 244 IS 2-3 BP 339 EP 349 DI 10.1016/S0301-0104(99)00131-7 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 211UQ UT WOS:000081180600016 ER PT J AU Ovchinnikov, YN Kresin, VZ AF Ovchinnikov, YN Kresin, VZ TI Heat capacity and upper critical field for inhomogeneous superconductors: Application to overdoped cuprates SO EUROPHYSICS LETTERS LA English DT Article ID TL2BA2CUO6+DELTA AB The presence of inhomogeneities has a great impact on the behavior of the heat capacity, particularly near the critical temperature. An expression for delta C = C-s - C-n is derived for this case, and is used to calculate the temperature dependence of the upper critical field. The analysis is in good agreement with the experimental data for overdoped cuprates. C1 Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ovchinnikov, YN (reprint author), Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow, Russia. NR 21 TC 4 Z9 4 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD JUN 15 PY 1999 VL 46 IS 6 BP 794 EP 800 DI 10.1209/epl/i1999-00334-5 PG 7 WC Physics, Multidisciplinary SC Physics GA 212YU UT WOS:000081245900015 ER PT J AU Cabrejos, ME Zhao, HL Guacucano, M Bueno, S Levican, G Garcia, E Jedlicki, E Holmes, DS AF Cabrejos, ME Zhao, HL Guacucano, M Bueno, S Levican, G Garcia, E Jedlicki, E Holmes, DS TI IST1 insertional inactivation of the resB gene: implications for phenotypic switching in Thiobacillus ferrooxidans SO FEMS MICROBIOLOGY LETTERS LA English DT Article DE Thiobacillus ferrooxidans; iron oxidation; insertion sequence; cytochrome biogenesis; resB; resC; lateral gene transfer; IST1 ID CYTOCHROME-C BIOGENESIS; SEARCH TOOL; SYSTEMS AB Thiobacillus ferrooxidans ATCC 19859 undergoes rapid phenotypic switching between a wild-type stare characterized by the ability to oxidize ferrous iron (FeII) and reduced sulfur compounds and a mutant state where it has lost the capacity to oxidize FeII but retains the ability to oxidize sulfur. The mutant has also gained the capacity to swarm. It is proposed that loss of FeII oxidation is due to the reversible transposition of the insertion sequence IST1 into resB encoding a putative cytochrome c-type biogenesis protein. Downstream from resB and co-transcribed with it is resC, encoding another putative cytochrome biogenesis protein. IST1 insertional inactivation of resB could result in the loss of activity of its target c-type cytochrome(s). This putative target cytochrome(s) is proposed to be essential for FeII oxidation but not for sulfur oxidation. Curiously, resB and I resC pertain to the proposed system II cytochrome biogenesis pathway whereas gamma Proteobacteria, of which T. ferrooxidans is a member, normally use system I. This could represent an example of lateral gene transfer. (C) 1999 Published by Elsevier Science B.V, All rights reserved. C1 Univ Santiago Chile, Fac Chem & Biol, Dept Sci Biol, Santiago, Chile. Univ Chile, Inst Biomed Sci, Santiago, Chile. Lawrence Livermore Natl Lab, Livermore, CA USA. RP Holmes, DS (reprint author), Univ Santiago Chile, Fac Chem & Biol, Dept Sci Biol, 3363 Alameda, Santiago, Chile. EM hogares@hotmail.com NR 18 TC 21 Z9 23 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1097 J9 FEMS MICROBIOL LETT JI FEMS Microbiol. Lett. PD JUN 15 PY 1999 VL 175 IS 2 BP 223 EP 229 DI 10.1111/j.1574-6968.1999.tb13624.x PG 7 WC Microbiology SC Microbiology GA 207DM UT WOS:000080920200011 PM 10386372 ER PT J AU Goldstein, DB Nerem, RS Barker, ES Austin, JV Binder, AB Feldman, WC AF Goldstein, DB Nerem, RS Barker, ES Austin, JV Binder, AB Feldman, WC TI Impacting lunar prospector in a cold trap to detect water ice SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POLES AB Lunar Prospector data support the contention that water ice reservoirs exist in the permanently shaded craters near the lunar poles. Yet the question remains whether the detected hydrogen abundance is actually water ice or is hydrogen in some other form. Present plans call for a controlled impact of Lunar Prospector into a polar crater at the end of July, 1999, in an attempt to liberate a small amount of water vapor that may be detected by ground- and space-based observatories. A positive spectral detection of water vapor or its photo-dissociated byproduct, OH, would be definite proof of the presence of water ice in the regolith. The following represents both an analysis of this method of searching for water ice as well as an announcement to the observing community of the event. C1 Univ Texas, Dept Aerosp Engn & Engn Mech, Austin, TX 78712 USA. Univ Texas, Space Res Ctr, Austin, TX 78712 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. Lunar Res Inst, Gilroy, CA USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Goldstein, DB (reprint author), Univ Texas, Dept Aerosp Engn & Engn Mech, Austin, TX 78712 USA. NR 14 TC 7 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1999 VL 26 IS 12 BP 1653 EP 1656 DI 10.1029/1999GL900384 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700003 ER PT J AU Duffy, PB Eby, M Weaver, AJ AF Duffy, PB Eby, M Weaver, AJ TI Effects of sinking of salt rejected during formation of sea ice on results of an ocean-atmosphere-sea ice climate model SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; MIXING PARAMETERIZATIONS; SENSITIVITY; DISTRIBUTIONS; SALINITY; LAYER AB We show that results of an ocean-atmosphere-sea-ice model are sensitive to the treatment of salt rejected during formation of sea ice. In our Control simulation, we place all rejected salt in the top ocean-model level. In the Plume simulation, we instantaneously mix rejected salt into the subsurface ocean, to a maximum depth which depends on local density gradients. This mimics the effects of subgrid-scale convection of rejected salt. The results of the Plume simulation are more realistic than those of the Control simulation: the spatial pattern of simulated salinities (especially in the Southern Ocean), deep-ocean temperatures, simulated sea-ice extents and surface air temperatures all agree better with observations. A similar pair of simulations using horizontal tracer diffusion instead of the Gent-McWilliams eddy parameterization show similar changes due to instantaneous mixing of rejected salt. C1 Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, Livermore, CA 94550 USA. Univ Victoria, Victoria, BC V8W 2Y2, Canada. RP Duffy, PB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, L-103, Livermore, CA 94550 USA. RI Weaver, Andrew/E-7590-2011; Eby, Michael/H-5278-2013 NR 16 TC 32 Z9 32 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1999 VL 26 IS 12 BP 1739 EP 1742 DI 10.1029/1999GL900286 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700025 ER PT J AU Richards, MA Bunge, HP Ricard, Y Baumgardner, JR AF Richards, MA Bunge, HP Ricard, Y Baumgardner, JR TI Polar wandering in mantle convection models SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VISCOSITY AB We calculate polar motion in models of 3-D spherical mantle convection at Rayleigh numbers up to 10(8) which include internal heating, radial viscosity variations, and an endothermic phase change. Isoviscous models yield rapid polar motion of order 3 degrees/Myr, but a factor of 30 increase in viscosity with depth reduces the rate of polar motion to about 0.5 degrees/Myr due to stabilization of the large-scale pattern of convection. Avalanching due to an endothermic phase change causes pulsating inertial interchange polar excursions of order 80-110 degrees and of duration 20-70 Myr. A layered viscosity model with an endothermic phase change yields only one inertial interchange event in 600 million years. These models show that the slow observed rate of post-Paleozoic true polar wander is not incompatible with higher rates inferred for earlier times. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Princeton Univ, Dept Geol & Geophys Sci, Princeton, NJ 08544 USA. Ecole Normale Super Lyon, Lab Sci Terre, F-69364 Lyon, France. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Richards, MA (reprint author), Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. RI ricard, yanick/C-6287-2009 OI ricard, yanick/0000-0002-0998-4670 NR 19 TC 37 Z9 38 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1999 VL 26 IS 12 BP 1777 EP 1780 DI 10.1029/1999GL900331 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700035 ER PT J AU Gutowski, M AF Gutowski, M TI Favorable performance of the DFT methods in predicting the minimum-energy structure of the lowest triplet state of WF4 SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article ID DENSITY-FUNCTIONAL-THEORY; HARTREE-FOCK; BASIS-SETS; MOLECULAR CALCULATIONS; CLOSED-SHELL; ELECTRON-GAS; APPROXIMATION; CHEMISTRY; POTENTIALS; STABILITY AB The tetrahedral structure of the lowest triplet state of the WF4 complex was examined using different variants of the density functional theory (DFT) and conventional ab initio methods. The low-level, conventional, ab initio methods, such as SCF, MP2, MP3, and CISD, predict the tetrahedral structure to be a minimum, whereas the DFT schemes predict an imaginary frequency for the e vibrational mode. Only after recovering electron correlation effects at the MP4 and higher levels, the conventional electronic structure methods also predict the T-d structure to be a second-order stationary point. This is not the correlation but the exchange part of the DFT functionals which is responsible for the discrepancy between the DFT and low-level, conventional, ab initio predictions. The lowering of symmetry to C-2v leads to a minimum on the lowest triplet potential energy surface and the electronic energy difference between the T-d and C-2v stationary points amounts to 0.85 and 0.96 kcal/mol at the B3LYP and CCSD(T) levels, respectively (C) 1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 369-375, 1999. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RP Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 35 TC 1 Z9 1 U1 0 U2 2 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0020-7608 EI 1097-461X J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD JUN 15 PY 1999 VL 73 IS 4 BP 369 EP 375 DI 10.1002/(SICI)1097-461X(1999)73:4<369::AID-QUA6>3.0.CO;2-B PG 7 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 197MM UT WOS:000080368600006 ER PT J AU Ohzono, T Glosli, JN Fujihira, M AF Ohzono, T Glosli, JN Fujihira, M TI Interpretation of difference in wearless friction observed between ordered organic monolayers with CH(3) and CF(3) terminal groups SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS LA English DT Article DE friction; molecular dynamics simulation; phenomenological simulation; interface; ordered organic monolayer ID ATOMIC-SCALE FRICTION; MOLECULAR-DYNAMICS SIMULATIONS; LANGMUIR-BLODGETT MONOLAYERS; STICK-SLIP MOTION; FORCE MICROSCOPY; DIAMOND SURFACES; SLIDING FRICTION; FILMS; GRAPHITE; TIP AB Molecular dynamics and corresponding simple phenomenological simulations are used to interpret the difference in wearless friction observed between two ordered monolayers with CHS and CF(3) terminal groups of the same alkyl chains bound at their ends to rigid substrates. The simulated interfaces correspond well to mesoscopic sliding interfaces. The simplified model previously proposed by us, where the frictional properties at such sliding interfaces are governed by two potentials which are closely related to the chemical and the structure of the film, suggests that the above frictional difference can be qualitatively interpreted by the difference in slopes of the corrugated interfacial potentials between two films at the repulsive regions. C1 Tokyo Inst Technol, Dept Biomol Engn, Midori Ku, Yokohama, Kanagawa 2268501, Japan. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Fujihira, M (reprint author), Tokyo Inst Technol, Dept Biomol Engn, Midori Ku, 4259 Nagatsuta, Yokohama, Kanagawa 2268501, Japan. EM mfujihir@bio.titech.ac.jp RI Ohzono, Takuya/M-5400-2016 OI Ohzono, Takuya/0000-0003-2185-2504 NR 42 TC 19 Z9 19 U1 0 U2 2 PU JAPAN SOC APPLIED PHYSICS PI TOKYO PA KUDAN-KITA BUILDING 5TH FLOOR, 1-12-3 KUDAN-KITA, CHIYODA-KU, TOKYO, 102-0073, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. Express Lett. PD JUN 15 PY 1999 VL 38 IS 6AB BP L675 EP L678 DI 10.1143/JJAP.38.L675 PG 4 WC Physics, Applied SC Physics GA 218XQ UT WOS:000081578700025 ER PT J AU Surh, MP AF Surh, MP TI Threshold stress behavior in thin film electromigration SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTERCONNECT LINES; ALUMINUM FILMS; AL-LINES; RELAXATION; METALLIZATIONS; MECHANISMS; GROWTH; MODEL AB Thin film electromigration is simulated using simple models for constitutive relations. Inhomogeneities in the mass deposition and stress fields can explain many features of the phenomenon. They imply that the threshold stress depends on the thin film microstructure and texture. The vacancy Z* parameter derived from the Blech threshold is increased in magnitude, in better agreement with experiments than earlier estimates. The predicted transient vacancy flux displays shorter decay times than the commonly used stress model, possibly in better agreement with experiment below threshold. Finally, nonlinear stress-strain relations are shown to be consistent with the behavior that is seen above threshold in passivated and unpassivated interconnects. (C) 1999 American Institute of Physics. [S0021-8979(99)05611-X]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Surh, MP (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. EM surh1@llnl.gov NR 24 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8145 EP 8154 DI 10.1063/1.370653 PG 10 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000018 ER PT J AU Mayer, TM Houston, JE Franklin, GE Erchak, AA Michalske, TA AF Mayer, TM Houston, JE Franklin, GE Erchak, AA Michalske, TA TI Electric field induced surface modification of Au SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; INTERFACIAL FORCE MICROSCOPY; ASSEMBLING MONOLAYER FILMS; NANOMETER-SCALE MECHANICS; GOLD NANOSTRUCTURES; QUANTUM CONTACT; SI(100) SURFACE; DIFFUSION; AU(111); TIP AB We discuss the role of localized high electric fields in the modification of Au surfaces with a W probe using the interfacial force microscope. Upon bringing a probe close to a Au surface, we measure both the interfacial force and the field emission current as a function of separation with a constant potential of 100 V between tip and sample. The current initially increases exponentially as the separation decreases. However, at a distance of less than similar to 500 Angstrom, the current rises sharply as the surface begins to distort and rapidly close the gap. Retraction of the tip before contact is made reveals the formation of a mound on the surface. We propose a simple model, in which the localized high electric field under the tip assists the production of mobile Au adatoms by detachment from surface steps, and a radial field gradient causes a net flux of atoms toward the tip by surface diffusion. These processes give rise to an unstable surface deformation which, if left unchecked, results in a destructive mechanical contact. We discuss our findings with respect to earlier work using voltage pulses in the scanning tunneling microscope as a means of nanofabrication. (C) 1999 American Institute of Physics. [S0021-8979(99)06812-7]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Mayer, TM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 40 TC 28 Z9 28 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8170 EP 8177 DI 10.1063/1.370656 PG 8 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000021 ER PT J AU Auciello, O Krauss, AR Gruen, DM Shah, P Corrigan, T Kordesch, ME Chang, RPH Barr, TL AF Auciello, O Krauss, AR Gruen, DM Shah, P Corrigan, T Kordesch, ME Chang, RPH Barr, TL TI Demonstration of Li-based alloy coatings as low-voltage stable electron-emission surfaces for field-emission devices SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MICROCATHODE ARRAYS; DIAMOND AB Alkali metals have extremely low work functions and are, therefore, expected to result in significant enhancement of the electron emission if they are used as coatings on Mo or Si microtip field-emission arrays (FEAs). However, the alkali metals are physically and chemically unstable in layers exceeding a few Angstrom in thickness. Maximum enhancement of electron emission occurs for alkali-metal layers 0.5-1 ML thick, but it is extremely difficult to fabricate and maintain such a thin alkali-metal coating. We present here an alternative means of producing chemically and thermally stable, self-replenishing lithium coatings approximately 1 ML thick, which results in a 13-fold reduction in the threshold voltage for electron emission compared with uncoated Si FEAs. (C) 1999 American Institute of Physics. [S0021-8979(99)02511-6]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Wisconsin, Dept Mat Sci, Milwaukee, WI 53211 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RP Auciello, O (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Chang, R.P.H/B-7505-2009 NR 24 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8405 EP 8409 DI 10.1063/1.370688 PG 5 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000055 ER PT J AU Zhang, WM Huebner, W Sampayan, SE Krogh, ML AF Zhang, WM Huebner, W Sampayan, SE Krogh, ML TI Response to "Comment on 'Mixed electron emission from lead zirconate-titanate ceramics'" [J-Appl. Phys. 85, 8495 (1999)] SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Understanding the mechanism of electron emission from ferroelectrics is in deed crucial for the application of ferroelectric cathodes. We appreciated the comments of Dorfman et al. on our recent article [J. Appl. Phys. 85, 6055 (1998)]. We believe the original proposed model is consistent and reasonable, i.e., the coexistence of ferroelectric and plasma emission from the same sample. (C) 1999 American Institute of Physics. [S0021-8979(99)05112-7]. C1 Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Allied Signal Fed Mfg & Technol, Kansas City, MO 64141 USA. RP Zhang, WM (reprint author), Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8497 EP 8498 DI 10.1063/1.370633 PG 2 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000073 ER PT J AU Shan, W Ager, JW Yu, KM Walukiewicz, W Haller, EE Martin, MC McKinney, WR Yang, W AF Shan, W Ager, JW Yu, KM Walukiewicz, W Haller, EE Martin, MC McKinney, WR Yang, W TI Dependence of the fundamental band gap of AlxGa1-xN on alloy composition and pressure SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GALLIUM NITRIDE; ELASTIC-CONSTANTS; PHOTOLUMINESCENCE; PARAMETERS; INN AB Optical absorption studies were performed to investigate the dependence of the fundamental band gap of Al-x Ga1-xN epitaxial films on Al content and applied hydrostatic pressure. The results of absorption measurements performed at atmospheric pressure yielded the variation of the band-gap energy E(x) = 3.43 + 1.44x + 1.33x(2) eV for the AlxGa1-xN system. Optical absorption edge associated with the direct Gamma band gap shifts linearly towards higher energy under applied pressure. By examining the pressure dependence of the absorption edge in samples with different AlN mole fractions and taking into account the difference of compressibility between the epitaxial films and sapphire substrate, the pressure coefficients for the direct Gamma band gaps of AlxGa1-xN were determined. (C) 1999 American Institute of Physics. [S0021-8979(99)03312-5]. 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. Honeywell Inc, Ctr Technol, Plymouth, MN 55420 USA. RP Shan, W (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012; McKinney, Wayne/F-2027-2014; OI Yu, Kin Man/0000-0003-1350-9642; McKinney, Wayne/0000-0003-2586-3139; Ager, Joel/0000-0001-9334-9751 NR 20 TC 76 Z9 76 U1 3 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8505 EP 8507 DI 10.1063/1.370696 PG 3 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000076 ER PT J AU Boyd, P LaRoche, J Gall, M Frew, R McKay, RML AF Boyd, P LaRoche, J Gall, M Frew, R McKay, RML TI Role of iron, light, and silicate in controlling algal biomass in subantarctic waters SE of New Zealand SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID EQUATORIAL PACIFIC-OCEAN; SUB-ANTARCTIC REGION; SUBTROPICAL CONVERGENCE; SOUTHERN-OCEAN; MARINE-PHYTOPLANKTON; EXPORT PRODUCTION; ATLANTIC SECTOR; ARCTIC PACIFIC; IN-SITU; DIATOMS AB Phytoplankton processes in subantarctic (SA) waters southeast of New Zealand were studied during austral autumn and spring 1997. Chlorophyll a (0.2-0.3 mu g L-l) and primary production (350-650 mg C m(-2) d(-1)) were dominated by cells <2 mu m (cyanobacteria) in both seasons. The photochemical efficiency of photosystem II (F-v/F-m) of cells was low (0.3), indicating physiological stress. Dissolved Fe (DFe) levels in surface waters were subnanomolar, and the molecular marker flavodoxin indicated that cells were iron stressed. In contrast, Subtropical Convergence (STC) and subtropical waters had higher algal biomass/production levels, particularly in spring. In these waters, DFe levels were >1 nmol kg(-1), there was little evidence of Fe-stressed algal populations, and F-v/F-m approached 0.60 at the STC. In addition to these trends, waters of SA origin were occasionally observed within the STC and north of the STC, and thus survey data were interpreted with caution. In vitro Fe enrichment incubations in SA waters resulted in a switch from flavodoxin expression to that of ferredoxin, indicating the alleviation of Fe stress. In another 6-day experiment, iron-mediated increases in chlorophyll a (in particular, increases in large diatoms) were of similar magnitude to those observed in a concurrent Si/Fe enrichment; ambient silicate levels were 4 mu M. A concurrent in vitro Fe enrichment, at irradiance levels comparable to the calculated mean levels experienced by cells in situ, resulted in relatively small increases (approximately twofold) in chlorophyll a. Thus, in spring, irradiance and Fe may both control diatom growth. In contrast: during summer, as mean irradiance increases and silicate levels decrease, Fe limitation, Fe/Si colimitation, or silicate limitation may determine diatom growth. C1 Univ Otago, Dept Chem, Ctr Chem & Phys Oceanog, Natl Inst Water & Atmospher Res, Dunedin, New Zealand. Brookhaven Natl Lab, Div Oceanog & Atmospher Sci, Upton, NY 11973 USA. Bowling Green State Univ, Dept Biol Sci, Bowling Green, OH 43403 USA. Natl Inst Water & Atmospher Res, Christchurch, New Zealand. RP Boyd, P (reprint author), Univ Otago, Dept Chem, Ctr Chem Oceanog, NIWA, POB 56, Dunedin, New Zealand. RI LaRoche, Julie/A-1109-2010; Frew, Russell/I-5591-2012; Boyd, Philip/J-7624-2014; OI Frew, Russell/0000-0002-6138-2116; Boyd, Philip/0000-0001-7850-1911; McKay, Robert/0000-0003-2723-5371 NR 59 TC 178 Z9 180 U1 2 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1999 VL 104 IS C6 BP 13395 EP 13408 DI 10.1029/1999JC900009 PG 14 WC Oceanography SC Oceanography GA 207BF UT WOS:000080914900010 ER PT J AU Cao, H He, Y Zhang, R Yuan, JP Sandreczki, TC Jean, YC Nielsen, B AF Cao, H He, Y Zhang, R Yuan, JP Sandreczki, TC Jean, YC Nielsen, B TI Degradation of polymer coating systems studied by positron annihilation spectroscopy. II. Correlation with free radical formation SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE photo-degradation; free volume; polymer coating; positron annihilation; free radical AB The photo-degradation of polymer coating systems due to irradiation by UV and Xenon light sources is studied using positron annihilation spectroscopy and electron spin resonance (ESR). Doppler broadened spectra of positron annihilation, as a function of slow positron implantation energy and ESR spectra, are measured in two types of polyurethane which were exposed, ex: situ, to UV irradiation for up to 800 h. The UV irradiation systematically decreases the S parameter as a function of exposure duration and increases the ESR signals. Thus, significant S parameter decrease is correlated with the ESR signal increase resulting from photo-degradation of polymers due to UV irradiation. Parallel in situ positron annihilation and ESR experiments are performed as a function of Xenon light exposure for up to 100 min. These results show that the photo-degradation of the polyurethane coatings involves initial free-radical formation, which is correlated with the subnanometer defects detected by positron annihilation spectroscopy. (C) 1999 John Wiley & Sons, Inc. C1 Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Jean, YC (reprint author), Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 23 TC 29 Z9 30 U1 0 U2 3 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 JUN 15 PY 1999 VL 37 IS 12 BP 1289 EP 1305 DI 10.1002/(SICI)1099-0488(19990615)37:12<1289::AID-POLB9>3.0.CO;2-P PG 17 WC Polymer Science SC Polymer Science GA 197BR UT WOS:000080345200009 ER PT J AU Garcia, VJ Schilling, CH AF Garcia, VJ Schilling, CH TI Ultrasonic velocity and reduction of surface area during solid-state sintering SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE ultrasonic velocity; surface area; solid-state sintering ID NONLINEAR ACOUSTOELASTIC PROPERTIES; POWDERS; CERAMICS; DENSIFICATION; SHAPES; DOMAIN; MEDIA; GREEN AB We studied the relationships between the ultrasonic velocity and the reduction of specific surface area during solid-state sintering and addressed three questions: (1) What must be the correlation between ultrasonic velocity and specific surface area reduction during the solid-state sintering of monosize spheres? (2) How is this correlation affected by the particle-size distribution and/or changes in packing coordination? (3) How do the answers to these questions help us improve the use of ultrasonic measurements to monitor sintering kinetics and microstructure evolution? From both a theoretical and experimental basis, we found a general power law that describes the relationship between ultrasonic velocity and the reduction of specific surface area during solid-state sintering: V-P/V-B proportional to (Delta S/S-o)(x). The power-law exponent x depends on three possible scenarios: (1) x <1 for ideal packing of monosize spheres; (2) x = 1 for random packing of monosize spheres where the average, particle coordination number changes upon sintering; and (3) x > 1 for specimens containing a broad distribution of particle sizes. We also demonstrated that this power law could be used with ultrasonic velocity measurements to obtain reasonable values of the activation energy for solid-state sintering. The power-law relationship is useful to characterize microstructure evolution during solid-state sintering and is useful to classify different materials in a ceramic manufacturing setting. It is also a simple modeling tool that opens the way to optimize control of the sintering process. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Garcia, VJ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 3053 Gilman Hall, Ames, IA 50011 USA. NR 52 TC 8 Z9 8 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 JUN 15 PY 1999 VL 265 IS 1-2 BP 42 EP 49 DI 10.1016/S0921-5093(99)00011-8 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 194TA UT WOS:000080208600006 ER PT J AU Park, JJ AF Park, JJ TI Creep strength of a tungsten-rhenium-hafnium carbide alloy from 2200 to 2400 K SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE steady-state creep; W-4Re-0.32Hfc; tungsten AB The high-temperature creep behavior of tungsten-4 wt.% rhenium-0.32 wt.% hafnium carbide (W-4Re-0.32HfC) was evaluated at temperatures ranging from 2200 to 2400 K and stresses ranging from 40 to 70 MPa in a vacuum less than 1.33 x 10(-6) MPa (1.0 x 10(-8) torr). The effects of temperature and stress on the steady-state creep rate were determined. The stress exponent for creep was 5.2, and the activation energy for creep was 594 kJ mol(-1). The creep strength of W-4Re-0.32HfC was compared with that of pure tungsten (W) and tungsten-5 wt.% rhenium (W-5Re) at a creep rate of 10(-6) s(-1) as a function of temperature. The temperature-compensated creep rate of W-4Re-0.32HfC was approximately two orders of magnitude less than that of pure W and one order of magnitude less than that of W-5Re. The creep strength of W-4Re-0.32HfC was correlated with its microstructural development during the high-temperature deformation. Transmission electron microscope (TEM) study of the creep tested samples revealed that the high creep strength of this alloy resulted from finely dispersed submicron-sized HfC particles. The strengthening effect of the HfC particles could be attributed to direct and indirect particle strengthening. Direct particle strengthening was caused by the retardation of subboundary dislocation movement by direct particle/dislocation interaction. Indirect particle strengthening was caused by the formation of subgrains, which in turn reduces the distance that dislocations can move before being immobilized at subgrain or grain boundaries. The strengthening effect of HfC particles was reduced as HfC particle diameter increased. (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, Los Alamos, NM 87545 USA. NR 14 TC 10 Z9 11 U1 1 U2 8 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 JUN 15 PY 1999 VL 265 IS 1-2 BP 174 EP 178 DI 10.1016/S0921-5093(98)01134-4 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 194TA UT WOS:000080208600020 ER PT J AU Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Donovan, SM Pearton, SJ Han, J Shul, RJ AF Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Donovan, SM Pearton, SJ Han, J Shul, RJ TI Comparison of ICl- and IBr-based plasma chemistries for inductively coupled plasma etching of GaN, InN and AlN SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE etch characteristics; inductively coupled plasma discharge; interhalogen compounds ID FIELD-EFFECT TRANSISTORS; MOLECULAR-BEAM EPITAXY; OHMIC CONTACTS; III-NITRIDES; SEMICONDUCTORS; GROWTH AB A parametric study of the etch characteristics of GaN, AlN and InN has been carried out with ICl/Ar and IBr/Ar chemistries in an inductively coupled plasma discharge. The etch rates of InN and AlN were relatively independent of plasma composition, while GaN showed increased etch rates with interhalogen concentration. Etch rates for all materials increased with increasing rf chuck power, indicating that higher ion bombardment energies are more efficient in enhancing sputter desorption of etch products. The etch rates increased for source powers up to 500 W and remained relatively flat thereafter for all materials, while GaN and InN showed maximum etch rates with increasing pressure. The etched GaN showed extremely smooth surfaces, which were somewhat better with IBr/Ar than with ICl/Ar. Maximum selectivities of similar to 14 for InN over GaN and > 25 for InN over AlN were obtained with both chemistries. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pearton, SJ (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 31 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD JUN 15 PY 1999 VL 60 IS 2 BP 95 EP 100 DI 10.1016/S0921-5107(99)00036-7 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 205TZ UT WOS:000080837800003 ER PT J AU Harringa, JL Cook, BA AF Harringa, JL Cook, BA TI Application of hot isostatic pressing for consolidation of n-type silicon-germanium alloys prepared by mechanical alloying SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE hot isostatic pressing; silicon-germanium; mechanical alloying ID GAP AB Improvements to state-of-the-art Si,,Ge,, thermoelectric alloys have been observed in laboratory-scale samples prepared by mechanical alloying (MA) and consolidated by hot pressing. This paper discusses consolidation of large-scale quantities of mechanically alloyed powders into production size compacts. Differences in thermoelectric properties have been observed between compacts prepared by conventional hot uniaxial pressing (HUP) and those prepared by hot isostatic pressing (HIP). due primarily to a difference in carrier concentration between alloys consolidated by the two techniques. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Harringa, JL (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 8 TC 7 Z9 8 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD JUN 15 PY 1999 VL 60 IS 2 BP 137 EP 142 DI 10.1016/S0921-5107(99)00023-9 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 205TZ UT WOS:000080837800011 ER PT J AU Li, ST Liu, GK Zhao, W AF Li, ST Liu, GK Zhao, W TI Converting Eu3+ between defect sites in BaFCl for persistent spectral hole burning SO OPTICS LETTERS LA English DT Article ID SILICATE-GLASSES; TEMPERATURE; DIFFUSION AB Persistent spectral hole burning (PSHB) is demonstrated in the F-7(0) --> D-5(0) optical transition of Eu3+ doped into crystals of BaFCl. For Eu3+ ions at two different lattice sites, persistent holes can be burned at temperatures below 77 K. The characteristics of the hole-burning process suggest that the observed PSHB effect is due to laser-excitation-induced site-to-site conversion. One type of Eu3+ site is converted into another type of defect site. This process is not optically reversible, and holes can be erased only when the temperature increases to 150 K. (C) 1999 Optical Society of America. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. RP Li, ST (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 12 TC 8 Z9 8 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 1999 VL 24 IS 12 BP 838 EP 840 DI 10.1364/OL.24.000838 PG 3 WC Optics SC Optics GA 208FK UT WOS:000080980000016 PM 18073871 ER PT J AU Maudlin, PJ Gray, GT Cady, CM Kaschner, GC AF Maudlin, PJ Gray, GT Cady, CM Kaschner, GC TI High-rate material modelling and validation using the Taylor cylinder impact test SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE anisotropic plasticity; polycrystal plasticity; Taylor anvil tests; tantalum deformation; zirconium deformation; rate-dependent plasticity ID DEFORMATION; POLYCRYSTALS; PLASTICITY; ALLOYS AB Taylor cylinder impact testing is used to validate anisotropic elastoplastic constitutive modelling by comparing polycrystal-computed yield-surface shapes (topography) with measured shapes from post-test Taylor specimens and quasi-static compression specimens. Measured yield-surface shapes are extracted from the experimental posttest geometries using classical r-value definitions modified for arbitrary stress state and specimen orientation. Rolled tantalum (body-centred-cubic metal) plate and clock-rolled zirconium (hexagonal-close-packed metal) plate are both investigated. The results indicate that an assumption of topography invariance with respect to strain rate is well justified for tantalum. However, a strong sensitivity of topography with respect to strain rate for zirconium was observed, implying that some accounting for a deformation mechanism rate dependence associated with lower-symmetry materials should be included in the constitutive modelling. Discussion of the importance of this rate dependence and texture evolution in formulating constitutive models appropriate for finite-element model applications is provided. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Maudlin, PJ (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Kaschner, George/H-4445-2013 NR 21 TC 34 Z9 34 U1 0 U2 13 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD JUN 15 PY 1999 VL 357 IS 1756 BP 1707 EP 1729 PG 23 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 211HT UT WOS:000081155400021 ER PT J AU Herman, GS AF Herman, GS TI Surface structure determination of CeO2(001) by angle-resolved mass spectroscopy of recoiled ions SO PHYSICAL REVIEW B LA English DT Article ID SCATTERING; YBA2CU3O7-X; CATALYSTS; CEO2(111); GROWTH; ENERGY; FILMS; CEO2 AB Angle-resolved mass spectroscopy of recoiled ions data was obtained for the CeO2(001) surface. Prior theoretical investigations have suggested that the (1 x 1) unreconstructed surface, terminated with bulk equivalent layers of either cerium or oxygen, is unstable due to a nonzero surface dipole. In this investigation, it was experimentally determined that the surface is terminated with 0.5 monolayers of oxygen. This model results in a stable surface with a zero dipole moment. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Herman, GS (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999,MSIN K8-93, Richland, WA 99352 USA. EM gs.herman@pnl.gov NR 23 TC 36 Z9 37 U1 2 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 23 BP 14899 EP 14902 DI 10.1103/PhysRevB.59.14899 PG 4 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500021 ER PT J AU Swenson, CA AF Swenson, CA TI Heat capacities (1 to 108 K) and linear thermal expansivities (1 to 300 K) of LuH0.148 single crystals: Thermal relaxation effects and the pairing transition SO PHYSICAL REVIEW B LA English DT Article ID SOLID-SOLUTION; NEUTRON-SCATTERING; LOW-TEMPERATURES; LONG-RANGE; HYDROGEN; LUTETIUM; YTTRIUM; DEUTERIUM; PROTON; MOTION AB Previous heat capacity (C-p) and linear thermal expansivity (alpha) data for the hexagonal alpha-LuHx and LuDx [LuH(D)(x)] single crystal alloys (x = 0, 0.005, 0.053) [C. A. Swenson, Phys. Rev. B 53, 3680 (1996)] have been extended to LuH0.148. A feature (a transition) near 170 K in alpha vs T for LuH0.053 crystals is much more pronounced for the present results, with the c-axis (a-axis) data showing an almost 40% (30%) decrease (increase) in alpha on cooling below 170 K. This transition, which was associated with the pairing of H along the c axis in next-nearest-neighbor tetrahedral sites on opposite sides of a lutetium ion, is not clearly defined, however, and, after a change in temperature, is characterized by isothermal drifts in the sample length with time constants which are very small at 175 K but increase to 100 h at 144 K. The migration energy associated with the temperature dependence of these time constants [0.26(3) eV] is approximately one-half that which is associated with high-temperature bulk diffusion. The conclusion is that pair breakup (pairing) does not occur (is not completed) at a unique transition temperature when the alloy is warmed (cooled), but is a thermally activated process, with the equilibrium fraction of paired H increasing with decreasing temperature, to achieve a saturation concentration below 140 K. The approach to pairing equilibrium for T< 175 K is diffusion limited. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Swenson, CA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 34 TC 1 Z9 1 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 23 BP 14926 EP 14936 DI 10.1103/PhysRevB.59.14926 PG 11 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500026 ER PT J AU van Veenendaal, M Fedro, AJ AF van Veenendaal, M Fedro, AJ TI Charge order and the metal-insulator transitions in A(1/2)A ' 1/2MnO3 SO PHYSICAL REVIEW B LA English DT Article ID MANGANESE OXIDES; SYSTEMS; STATES AB An interpretation is given for the metal-insulator transitions occurring in A (1/2)A(1/2)(')MnO(3) using the double-exchange model but including the coupling of the electron to the Jahn-Teller distortions and a finite Coulomb interaction between electrons in the twofold degenerate e(g) orbitals. We find that, whereas the ferromagnetic state is metallic, the insulating state is polaronic. As one lowers the temperature, a transition from the ferromagnetic state to the CE phase is observed, which is, due to the strong phonon renormalization of the bandwidth, accompanied by a change in resistivity of several orders of magnitude. In order to obtain the observed magnetic structure, i.e., CE type, it is essential to include the lowering of the on-site energy due to polaronic self-energy effects. We present a way of building the charge-ordered magnetic structures out of small units of a "localized" 3z(2)-r(2) polaron with four antiferromagnetic and two ferromagnetic neighboring t(2g) core spins. [S0163-1829(99)00923-6]. C1 No Illinois Univ, De Kalb, IL 60115 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP van Veenendaal, M (reprint author), Philips Res Labs, Prof Holstlaan 4, NL-5656 AA Eindhoven, Netherlands. NR 24 TC 4 Z9 4 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 JUN 15 PY 1999 VL 59 IS 23 BP 15056 EP 15061 DI 10.1103/PhysRevB.59.15056 PG 6 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500037 ER PT J AU Mattila, T Wang, LW Zunger, A AF Mattila, T Wang, LW Zunger, A TI Electronic consequences of lateral composition modulation in semiconductor alloys SO PHYSICAL REVIEW B LA English DT Article ID SHORT-PERIOD SUPERLATTICES; MOLECULAR-BEAM EPITAXY; LAYER ORDERING PROCESS; (INP)(2)/(GAP)(2) QUANTUM WIRES; CYCLOTRON-RESONANCE; BAND-STRUCTURE; VALENCE-BAND; III-V; GAAS; PHOTOEMISSION AB Lateral composition modulation (CM) is a periodic, position-dependent variation in alloy composition occurring in the substrate plane, perpendicular to the growth direction. It can be induced by growing size-mismatched short-period AC/BC superlattices (SL). Hers we study the electronic structure induced by such lateral composition modulation in GaAs/InAs, GaP/InP, and AlP/GaP, in search of optical properties relative to the corresponding random alloys. We investigate in detail the properties of (a) pure CM without any SL, (b) pure SL without any CM, and (c) the combined CM+SL system. The systems are modeled by constructing a large supercell where the cation sublattice sites are randomly occupied in the lateral (vertical) direction according to the composition variation induced by CM (SL). The atomic structure and strain induced by CM and SL are explicitly taken into account using an atomistic force field. This approach is found to be crucial for an accurate description of the microscopic strain in CM+SL systems. The electronic structure is solved using specially constructed empirical pseudopotentials and plane-wave expansion of the wave functions. We find that (i) CM in GaAs/InAs and GaP/InP systems induces type-I band alignment (electrons and holes localized in the same spatial region), while CM in AlP/GaP is shown as an example exhibiting type-II band alignment. (ii) Ch? and SL both induce significant contributions (which add up nearly linearly) to band-gap redshift with respect to random alloy. CM in GaP/InP is found to induce larger band-gap redshifts than in GaAs/InAs due to larger band offsets in the former system. (iii) The symmetry of electronic states at the valence band maximum is sensitively affected by CM: the lowest energy optical transitions exhibit strong polarization where transitions polarized perpendicular to the CM are favored, while transitions polarized parallel to the CM are surpressed by bring shifted to higher energy. These observations, as well as the magnitude of the predicted band-gap redshift, agree with available experimental data, and suggest that control of composition modulation during growth might be used to tailor band gaps, carrier localization, and transition polarizations relative to random alloys. [S0163-1829(99)02824-6]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Mattila, T (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. EM alex_zunger@nrel.gov RI Zunger, Alex/A-6733-2013 NR 63 TC 40 Z9 40 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 JUN 15 PY 1999 VL 59 IS 23 BP 15270 EP 15284 DI 10.1103/PhysRevB.59.15270 PG 15 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500063 ER PT J AU Lee, EY AF Lee, EY TI Monte Carlo dynamics below the Au-GaAs interface for ballistic-electron-emission microscopy SO PHYSICAL REVIEW B LA English DT Article ID ELASTIC-SCATTERING; TRANSPORT; SPECTROSCOPY; FIELD; INAS AB Monte Carlo simulations of hot electron transport in the Gamma, L, and X valleys of GaAs were performed to study the transport dynamics for ballistic-electron-emission microscopy (BEEM) of mesoscopic objects beneath the Au-GaAs interface. For the starting electron flux distribution at the interface, the distribution for the strong scattering limit of Smith-Lee-Narayanamurti theory [D. L. Smith, E. Y. Lee, and V. Narayanamurti, Phys. Rev. Lett. 80, 2433 (1998)] was used. For the subsequent electron transport within GaAs, phonon and intervalley scatterings were simulated. With increasing object depth beneath the Au-GaAs interface, the simulations predict (1) significant cooling of hot electrons, on the order of similar to 3 meV/nm at 1.5 V, and (2) significant redistribution of electrons among the conduction valleys. These effects should be taken into account for proper interpretation of BEEM experiments, especially for large biases and deep objects. [S0163-1829(99)07623-7]. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Lee, EY (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 20 TC 4 Z9 4 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 23 BP 15332 EP 15336 DI 10.1103/PhysRevB.59.15332 PG 5 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500070 ER PT J AU Dinh, LN McLean, W Schildbach, MA Balooch, M AF Dinh, LN McLean, W Schildbach, MA Balooch, M TI Synthesis and characterization of Si/Cs/O nanocluster thin films with negative electron affinity SO PHYSICAL REVIEW B LA English DT Article ID FIELD-EMISSION; WORK-FUNCTION; SI NANOCRYSTALS; EMITTER ARRAYS; POROUS SI; DIAMOND; SURFACE; PHOTOLUMINESCENCE; SILICON; CESIUM AB Patterned and unpatterned thin films of Si/Cs/O nanoclusters have been synthesized by the technique of supersaturated thermal vaporization of Si and Cs in an oxygen background gas. These films, which were deposited onto conducting or semiconducting substrates, exhibit negative electron affinity (NEA) as evidenced by ultraviolet photoemission spectroscopy. Photo, secondary, and field electron emission properties of these nanocluster films were investigated with photoelectron emission microscopy, field electron emission microscopy, secondary electron microscopy, and current-voltage measurements. Flat cathodes covered with thin films of Si/Cs/O nanoclusters exhibited high current outputs and lower turn-on fields (<8.7 V/mu m) than most NEA diamond surfaces and gated Si or Mo tip arrays. The films' NEA is unaffected by air exposure and is stable to high-temperature annealing (550 degrees C). The electron emission property of the NEA nanocluster films can be best explained by a subband gap abundant surface-state nanocluster model. A field-emission display unit with a simple diode structure containing a flat cathode coated with a thin film of Si/Cs/O nanoclusters has also been built to demonstrate the potential application of this material in cold cathode electron emitting devices, particularly field-emission flat panel displays. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dinh, LN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 44 TC 20 Z9 20 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 JUN 15 PY 1999 VL 59 IS 23 BP 15513 EP 15522 DI 10.1103/PhysRevB.59.15513 PG 10 WC Physics, Condensed Matter SC Physics GA 210ZB UT WOS:000081134500093 ER PT J AU Jennison, DR Verdozzi, C Schultz, PA Sears, MP AF Jennison, DR Verdozzi, C Schultz, PA Sears, MP TI Ab initio structural predictions for ultrathin aluminum oxide films on metallic substrates SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; OXYGEN; SURFACES; SAPPHIRE; ENERGIES; AL(111); AL2O3 AB On several metallic substrates, first-principles density-functional calculations of Al2O3 5-7 Angstrom films predict a structure, stabilized by interfacial electrostatics, which has no bulk counterpart. In two and three O-layer films, Al ions prefer distorted tetrahedral sites, over the normal octahedral sites. The film/substrate interface is found to consist of strongly chemisorbed oxygen and is the determining factor in geometry; these oxygens are only weakly perturbed by the presence of Al2O3 overlayers. In an experimentally relevant film (two O layers, as on NiAl), Al ions are nearly coplanar with surface O ions; thus observing "oxygen termination'' does not indicate a polar surface. As a test case, we find Pt overlayers bind similarly as to alpha-Al2O3, suggesting these films may indeed be useful models for thicker materials. [S0163-1829(99)50524-9]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM drjenni@sandia.gov NR 31 TC 66 Z9 66 U1 1 U2 7 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 JUN 15 PY 1999 VL 59 IS 24 BP 15605 EP 15608 PG 4 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700008 ER PT J AU Emery, VJ Kivelson, SA Zachar, O AF Emery, VJ Kivelson, SA Zachar, O TI Classification and stability of phases of the multicomponent one-dimensional electron gas SO PHYSICAL REVIEW B LA English DT Article ID T-J LADDER; HUBBARD-MODEL; KONDO-LATTICE; SPIN-GAP; GROUND-STATE; CHAIN; SUPERCONDUCTIVITY; THEOREM; LIQUID AB The classification of the ground-state phases of complex one-dimensional electronic systems is considered in the context of a fixed-point strategy. Examples are multichain Hubbard models, the Kondo-Heisenberg model, and the one-dimensional electron gas in an active environment.;It is shown that, in order to characterize the low-energy physics, it is necessary to analyze the perturbative stability of the possible fixed paints, to identify all discrete broken symmetries; and to specify the quantum numbers and elementary wave vectors of the gapless excitations. Many previously proposed exotic phases of multichain Hubbard models are shown to be unstable because of the "spin-gap proximity effect." A useful tool in this analysis is a generalization of Luttinger's theorem, which shows that there is a gapless even-charge mode, in any incommensurate N-component system. [S0163-1829(99)03124-0]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Univ Paris Sud, Phys Solides Lab, F-91405 Orsay, France. RP Emery, VJ (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 40 TC 38 Z9 38 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 JUN 15 PY 1999 VL 59 IS 24 BP 15641 EP 15653 DI 10.1103/PhysRevB.59.15641 PG 13 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700014 ER PT J AU Ravindran, P Delin, A James, P Johansson, B Wills, JM Ahuja, R Eriksson, O AF Ravindran, P Delin, A James, P Johansson, B Wills, JM Ahuja, R Eriksson, O TI Magnetic, optical, and magneto-optical properties of MnX (X=As, Sb, or Bi) from full-potential calculations SO PHYSICAL REVIEW B LA English DT Article ID ELECTRIC-FIELD GRADIENTS; FIRST-PRINCIPLES; MAGNETOCRYSTALLINE ANISOTROPY; 1ST-PRINCIPLES CALCULATION; HYPERFINE FIELDS; HEUSLER ALLOYS; BAND-STRUCTURE; MNBIAL FILMS; MNSB; SYSTEMS AB The magneto-optic (MO) Kerr and Faraday spectra for manganese pnictides are calculated using the all electron, relativistic, full-potential linear muffin-tin orbital method. The amplitude of our calculated spectra are found to be in good agreement with corresponding experimental spectra. Although the MO property is a rather complicated function of the diagonal and off-diagonal elements of the optical conductivity tenor, present theory nevertheless provides very practical insight about its origin in these compounds. The largest Kerr effect observed in MnBi can be understood as a combined effect of maximal exchange splitting of Mn 3d states and the nearly maximal spin-orbit (s-o) coupling of Bi. The frequency-dependent optical properties, namely reflectivity, absorption coefficient, electron-energy-loss spectra, refractive index, extinction coefficient are given. From our calculations (including spin-orbit coupling and orbital polarization) the site-projected spin and orbital moments are also obtained and compared to the available experimental values and a good agreement is found. The magnetic anisotropy energy is calculated with a minimal number of approximations for the three systems. A disagreement between theory and experiment is found. Using the generalized gradient corrected full-potential Linear augmented plane-wave method we have calculated the unscreened plasma frequencies and the hyperfine parameters such as electric-field gradient as well as the hyperfine field. [S0163-1829(99)01419-8]. C1 Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ravindran, P (reprint author), Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, Box 530, S-75121 Uppsala, Sweden. EM P.Ravindran@fysik.uu.se RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 98 TC 101 Z9 101 U1 3 U2 22 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 15680 EP 15693 DI 10.1103/PhysRevB.59.15680 PG 14 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700018 ER PT J AU Stumpf, RR Carpinelli, JM Weitering, HH AF Stumpf, RR Carpinelli, JM Weitering, HH TI Apparent charge transfer at the GexPb1-x/Ge(111) interface SO PHYSICAL REVIEW B LA English DT Article ID SUBMONOLAYER PHASES; MOSAIC PHASE; SURFACE; PB; GE(111) AB We investigate the apparent charge transfer between adatoms in the GexPb(1-x)/Ge(111) interface both experimentally and theoretically. Scanning tunneling microscopy and surface core-level measurements suggest significant charge transfer from the Ge adatoms to the Pb adatoms. However, first-principles calculations unambiguously find that the total electronic displacement is negligibly small and that the results of published experiments can be explained as a result of bond rearrangement. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Weitering, HH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 18 TC 14 Z9 14 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 15779 EP 15783 DI 10.1103/PhysRevB.59.15779 PG 5 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700029 ER PT J AU Wang, LW Zunger, A AF Wang, LW Zunger, A TI Linear combination of bulk bands method for large-scale electronic structure calculations on strained nanostructures SO PHYSICAL REVIEW B LA English DT Article ID SEMICONDUCTOR QUANTUM DOTS; PSEUDOPOTENTIAL CALCULATION; P METHOD; SUPERLATTICES; ENERGY; WIRES; EXCITONS; STATES; 8-BAND AB A "strained linear combination of bulk bands" method is introduced for calculating the single-particle electronic states of strained, million-atom nanostructure systems, within an empirical pseudopotential Hamiltonian. This method expands the wave functions of a nanostructure (superlattice, wire, and dot) as linear combinations of bulk Bloch states of the constituent materials, over band indices n and wave vectors k. This allows one to use physical intuition in selecting the n and k that are most relevant for a given problem. This constitutes a useful approximation over the "direct diagonalization" approach where the basis is complete (individual plane waves) but unintuitive. It also constitutes a dramatic improvement upon the k.p approach, where the continuum model Hamiltonian is used, losing the atomistic details of the system. For a pyramidal InAs quantum dot embedded in GaAs, we find electronic eigenenergies that are within 20 meV of the exact direct diagonalization calculation, while the speed of the current method is 100-1000 times faster. The sublinear scaling of the current method with the size of the system enables one to calculate the atomistic electronic states of a million-atom system on a personal computer in about 10 h. Sufficient detail is provided in the formalism, so that the method can be promptly implemented. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wang, LW (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 32 TC 158 Z9 161 U1 2 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 15806 EP 15818 DI 10.1103/PhysRevB.59.15806 PG 13 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700033 ER PT J AU Williamson, AJ Zunger, A AF Williamson, AJ Zunger, A TI InAs quantum dots: Predicted electronic structure of free-standing versus GaAs-embedded structures SO PHYSICAL REVIEW B LA English DT Article ID STRAIN AB Using an atomistic pseudopotential approach, we have contrasted the (i) strain profiles, (ii) strain-modified band offsets, (iii) energies of confined electrons and holes, and (iv) wave functions and Coulomb interactions between electrons and holes for three types of InAs quantum dots: (a) a free-standing spherical dot, (b) a GaAs-embedded spherical dot, and (c) a GaAs-embedded pyramidal dot. A comparison of (a) and (b) reveals the effects of strain, while a comparison of (b) and (c) reveals the effects of shape. We fmd that the larger band offsets in the "free-standing" dots (i) produce greater quantum confinement of electrons and holes and (ii) act to confine the wave functions more strongly within the dot, resulting in larger electron-hole Coulomb energies. The lower symmetry of the pyramidal dot produces a richer strain profile than the spherical dots, which splits the degeneracy of the hole states and polarizes the emitted light. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Williamson, AJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 20 TC 125 Z9 126 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 15819 EP 15824 DI 10.1103/PhysRevB.59.15819 PG 6 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700034 ER PT J AU Yu, ZG Smith, DL Saxena, A Bishop, AR AF Yu, ZG Smith, DL Saxena, A Bishop, AR TI Green's function approach for a dynamical study of transport in metal/organic/metal structures SO PHYSICAL REVIEW B LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; LIGHT-EMITTING-DIODES; ORGANIC THIN-FILMS; CHARGED SOLITON; ELECTRIC-FIELD; LATTICE FLUCTUATIONS; CONDUCTING POLYMERS; POLYACETYLENE; TRANSMISSION; MOTION AB We develop an efficient Green's function formalism to study transport in organic tunneling devices. We find a crossover behavior of the transport from free-electron-like to polaronlike as the ratio between the electronic and organic lattice vibration time scales is varied. If the electronic time scale is fast compared to the lattice vibration time scale, the lattice motion lags behind the incoming wave packet and the transmission is similar to that in a static case where the lattice is frozen. In the opposite limit, the lattice follows the electron and the first transmission peak shifts from the conduction-band edge toward the self-trapped polaron level. We investigate the transmission coefficient, the transfer of energy between the incident electron and the lattice, and the time evolution of the electron energy distribution function as the ratio of these time scales is changed. To simulate lattice fluctuations we study a preexisting lattice distortion and find enhanced subgap transmission. Our results are important for understanding electrical injection in polymer light-emitting diodes and other organic-based electronic device structures, and electrical transport in molecular wires. [S0163-1829(99)04223-X]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Yu, ZG (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Yu, Z/B-5547-2009 NR 33 TC 42 Z9 43 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 16001 EP 16010 DI 10.1103/PhysRevB.59.16001 PG 10 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700054 ER PT J AU Firlej, L Kirova, N Zahab, A AF Firlej, L Kirova, N Zahab, A TI Field-induced diffusion of gold and related phase transformations in the C-60 and C-70 fullerenes SO PHYSICAL REVIEW B LA English DT Article ID THIN-FILMS; CONDUCTIVITY AB The intercalation of metal M (M = Au, Ag, In) from the electrode into the polycrystalline C-60 and C-70 thin films is studied by time-dependent and space-resolved conductivity measurements under controlled oxygen-free atmosphere at different temperatures and electric fields. The time resistivity behavior is interpreted on the basis of electric-field-induced diffusion of metal ions from the electrodes to the interstitials of the fullerene crystal lattice and local formation of MxC60 and MxC70 phases. A comparison between the resistivity behaviors of C-60 and C-70 thin films provides evidence that the process is sensitive to the electronic level structure of the fullerenes molecules. [S0163-1829(99)08823-2]. C1 Univ Montpellier 2, Dynam Phases Condensees Grp, F-34095 Montpellier 05, France. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Firlej, L (reprint author), Univ Montpellier 2, Dynam Phases Condensees Grp, Pl E Bataillon, F-34095 Montpellier 05, France. NR 9 TC 11 Z9 11 U1 1 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1999 VL 59 IS 24 BP 16028 EP 16032 DI 10.1103/PhysRevB.59.16028 PG 5 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700057 ER PT J AU Lin, SY Fleming, JG Sigalas, MM Biswas, R Ho, KM AF Lin, SY Fleming, JG Sigalas, MM Biswas, R Ho, KM TI Photonic band-gap microcavities in three dimensions SO PHYSICAL REVIEW B LA English DT Article ID PERIODIC STRUCTURES; CRYSTALS AB The localization of light to less than a cubic wavelength, lambda(3), in all three dimensions has important quantum consequences. A defect formed inside a three-dimensional (3D) photonic crystal provides a unique optical environment for light localization. Single-mode defect cavities were built from an infrared 3D photonic crystal. A cavity state with a modal volume of 2X(lambda/2)(3) was observed. This is, to the best of our knowledge, the smallest cavity mode in a 3D photonic crystal ever observed at infrared wavelengths. [S0163-1829(99)51124-7]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Iowa State Univ, Dept Phys & Astron, US DOE, Ames Lab, Ames, IA 50011 USA. RP Lin, SY (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM SLIN@sandia.gov NR 17 TC 10 Z9 8 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 JUN 15 PY 1999 VL 59 IS 24 BP R15579 EP R15582 PG 4 WC Physics, Condensed Matter SC Physics GA 210ZD UT WOS:000081134700001 ER PT J AU Gao, Y Liu, J Shi, M Elder, SH Virden, JW AF Gao, Y Liu, J Shi, M Elder, SH Virden, JW TI Dense arrays of well-aligned carbon nanotubes completely filled with single crystalline titanium carbide wires on titanium substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID FIELD-EMISSION AB We report the synthesis of dense and uniform arrays of well-aligned carbon nanotubes on titanium substrates over large areas, in which all the tubes are simultaneously and completely filled with single crystals of titanium carbide. The carbon nanotubes were synthesized by thermal chemical vapor deposition of ethylene on iron-coated substrates, while the titanium carbide was simultaneously formed inside the nanotubes through a simultaneous solid state reaction. We propose a base dissolution and precipitation mechanism for the growth of titanium carbide filled carbon nanotubes. The same method can be used to fabricate oriented nanotube arrays filled with other carbides on a variety of substrates over large scale. Such well-aligned and densely packed uniform carbon nanotubes, completely filled with nanowires on conducting substrates, will have great potential in many applications. (c) 1999 American Institute of Physics. [S0003-6951(99)01924-5]. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Gao, Y (reprint author), Pacific NW Lab, POB 999,MS K8-93, Richland, WA 99352 USA. NR 14 TC 35 Z9 36 U1 0 U2 11 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 JUN 14 PY 1999 VL 74 IS 24 BP 3642 EP 3644 DI 10.1063/1.123208 PG 3 WC Physics, Applied SC Physics GA 202VB UT WOS:000080671900017 ER PT J AU Thompson, JR Ossandon, JG Krusin-Elbaum, L Song, KJ Christen, DK Ullmann, JL AF Thompson, JR Ossandon, JG Krusin-Elbaum, L Song, KJ Christen, DK Ullmann, JL TI Quantum constraints on technological superconductors SO APPLIED PHYSICS LETTERS LA English DT Article ID SPLAYED COLUMNAR DEFECTS; PROTON IRRADIATION; CURRENT-DENSITY; FLUX-CREEP; TAPES; BI2SR2CACU2O8; VORTICES AB Vortex pinning in textured Bi2Sr2CaCu2Ox/Ag superconducting tapes was enhanced by irradiation with 0.8 GeV protons, creating randomly oriented columnar defects. Measurements of the current density J versus time show that thermally-activated current decay was greatly decreased, compared with unirradiated tapes. However, temperature-independent quantum tunneling of vortices considerably limits J and its temporal stability, for a significant fraction of the finite-J(c) region. (c) 1999 American Institute of Physics. [S0003-6951(99)03324-0]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Univ Talca, Curico, Chile. IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Thompson, JR (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 13 TC 11 Z9 11 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 JUN 14 PY 1999 VL 74 IS 24 BP 3699 EP 3701 DI 10.1063/1.123225 PG 3 WC Physics, Applied SC Physics GA 202VB UT WOS:000080671900036 ER PT J AU Bourassa, J Lee, B Bernard, S Schoonover, J Ford, PC AF Bourassa, J Lee, B Bernard, S Schoonover, J Ford, PC TI Flash photolysis studies of Roussin's black salt anion: Fe4S3(NO)(7)(-) SO INORGANIC CHEMISTRY LA English DT Article ID NITRIC-OXIDE; NITROSYL COMPLEXES; METAL-COMPLEXES; EXCITED-STATE; RED SALT; PHOTOCHEMISTRY; SPECTROSCOPY AB A time-resolved optical (UV-vis) spectroscopic study of Roussin's black salt anion, Fe4S3(NO)(7)(-), revealed two separate intermediates, X and Y, following laser flash photolysis. Both intermediates react with nitric oxide with second-order kinetics to re-form the parent complex (k(NO)(X) = 1.3 x 10(7) M-1 s(-1); k(NO)(Y) = 7.0 x 10(5) M-1 S-1 in aqueous solutions). The shorter-lived intermediate X was observed in time resolved infrared spectroscopic studies. Isotopic labeling experiments involving the exchange of black salt nitrosyls with (NO2-)-N-15 or (NO)-N-15-O-18 were used to probe the correlation between nu(NO) bands and the anion structures. The identities of the intermediates are interpreted in terms of photolytic loss of chemically distinct nitrosyls found on the Fe4S3(NO)(7)(-) anion. C1 Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. Univ Calif Los Alamos Natl Lab, Integrated Spect Lab, Los Alamos, NM 87545 USA. RP Ford, PC (reprint author), Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. RI Bernhard, Stefan/A-9389-2008; Ford, Peter/D-1826-2011 OI Ford, Peter/0000-0002-5509-9912 NR 17 TC 54 Z9 54 U1 1 U2 3 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 JUN 14 PY 1999 VL 38 IS 12 BP 2947 EP 2952 DI 10.1021/ic981282v PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 207WY UT WOS:000080959800027 ER PT J AU Hansen, DL Cotter, J Fisher, GR Leung, KT Martin, R Neill, P Perera, RCC Simon, M Uehara, Y Vanderford, B Whitfield, SB Lindle, DW AF Hansen, DL Cotter, J Fisher, GR Leung, KT Martin, R Neill, P Perera, RCC Simon, M Uehara, Y Vanderford, B Whitfield, SB Lindle, DW TI Multi-ion coincidence measurements of methyl chloride following photofragmentation near the chlorine K-edge SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID MULTICOINCIDENCE MASS-SPECTROMETRY; ADVANCED LIGHT-SOURCE; PHOTOEXCITATION; MOLECULES; FRAGMENTATION; DISSOCIATION; DYNAMICS; HCL AB Relaxation dynamics of CH3Cl following core-shell photoexcitation in the neighbourhood of the chlorine K-edge (approximate to 2.8 keV) were studied via multi-ion coincidence measurements using a time-of-flight mass spectrometer. The data provide evidence for sequential fragmentation moderated by Coulombic interactions among the fragments. The sequential nature of the fragmentation indicates that chemical forces, especially between the carbon and chlorine atoms, are dominant in determining the kinematics of the fragmentation. This is especially true on resonance where fast dissociation is observed following electron excitations to the 8a(1) antibonding orbital. C1 Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Univ Paris Sud, LURE, F-91405 Orsay, France. CENS, SPAM, DRECAM, CEA, F-91191 Gif Sur Yvette, France. Mitsubishi Elect Co, Amagasaki, Hyogo 661, Japan. Univ Wisconsin, Dept Phys & Astron, Eau Claire, WI 54702 USA. RP Hansen, DL (reprint author), Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. NR 23 TC 11 Z9 11 U1 0 U2 5 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 JUN 14 PY 1999 VL 32 IS 11 BP 2629 EP 2647 DI 10.1088/0953-4075/32/11/312 PG 19 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 207EU UT WOS:000080923800013 ER PT J AU Srajer, G Yahnke, CJ Haeffner, DR Mills, DM Assoufid, L Harmon, BN Zuo, Z AF Srajer, G Yahnke, CJ Haeffner, DR Mills, DM Assoufid, L Harmon, BN Zuo, Z TI Magnetic Compton scattering study of the invar alloy Fe3Pt SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID POLARIZED SYNCHROTRON RADIATION; DEPENDENT MOMENTUM DISTRIBUTION; LOW-SPIN STATE; THERMAL-EXPANSION; IRON; TRANSITION; FE; FLUCTUATIONS; DYNAMICS; RAYS AB The magnetic Compton profile (MCP) for ordered Fe72Pt28 has been measured at T = 305 and 490 K. The shape of the MCPs are compared to one obtained from first principles band-structure calculations for the ferromagnetic ground state. The theoretical analysis includes a decomposition of the various orbital and atomic contributions. The experiments indicate a discernible change in the shape of the MCP with increasing temperature, and possible implications for the observed change in shape are discussed. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Srajer, G (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. NR 33 TC 4 Z9 4 U1 2 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUN 14 PY 1999 VL 11 IS 23 BP L253 EP L260 DI 10.1088/0953-8984/11/23/103 PG 8 WC Physics, Condensed Matter SC Physics GA 207FC UT WOS:000080924600003 ER PT J AU Savage, MJ Scaldeferri, KA Wise, MB AF Savage, MJ Scaldeferri, KA Wise, MB TI n+p -> d+gamma in effective field theory SO NUCLEAR PHYSICS A LA English DT Article ID CHIRAL LAGRANGIANS; NUCLEAR-FORCES AB The radiative capture process n + p --> d + gamma provides clear evidence for meson exchange currents in nuclear physics. We compute this process at low energies using a recently developed power counting for the effective field theory that describes nucleon-nucleon interactions. The leading order contribution to this process comes from the photon coupling to the nucleon magnetic moments. At subleading order there are other contributions. Among these are graphs where the photon couples directly to pions, i.e. meson exchange currents. These diagrams are divergent and require the presence of a local four-nucleon-one-photon counterterm. The coefficient of this operator is determined by the measured cross section, sigma(expt) = 334.2 +/- 0.5 mb, for incident neutrons with speed \upsilon\ = 2200 m/s. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Phys, Seattle, WA 98915 USA. Jefferson Lab, Newport News, VA 23606 USA. CALTECH, Pasadena, CA 91125 USA. RP Savage, MJ (reprint author), Univ Washington, Dept Phys, Seattle, WA 98915 USA. NR 28 TC 20 Z9 20 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD JUN 14 PY 1999 VL 652 IS 3 BP 273 EP 286 DI 10.1016/S0375-9474(99)00146-3 PG 14 WC Physics, Nuclear SC Physics GA 208ZK UT WOS:000081022400004 ER PT J AU Barbieri, R Giusti, L Hall, LJ Romanino, A AF Barbieri, R Giusti, L Hall, LJ Romanino, A TI Fermion masses and symmetry breaking of a U(2) flavour symmetry SO NUCLEAR PHYSICS B LA English DT Article DE flavour; symmetries; potential ID QUARK MASSES; PREDICTIONS; MODEL AB We show how a specific sequential breaking pattern of a U(2) flavour symmetry occurs automatically in a broad framework. The relative orientation in U(2) space of the spurion fields that breaks the U(2) symmetry is uniquely fixed, thus determining the form of the fermion mass matrices in a predictive way. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Scuola Normale Super Pisa, I-56126 Pisa, Italy. Ist Nazl Fis Nucl, Sez Pisa, I-56126 Pisa, Italy. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Oxford, Dept Phys, Oxford OX1 3NP, England. RP Barbieri, R (reprint author), Scuola Normale Super Pisa, I-56126 Pisa, Italy. RI Romanino, Andrea/I-3480-2012; Giusti, Leonardo/F-4311-2011 OI Romanino, Andrea/0000-0002-5915-4747; Giusti, Leonardo/0000-0003-2002-8134 NR 9 TC 35 Z9 35 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD JUN 14 PY 1999 VL 550 IS 1-2 BP 32 EP 40 DI 10.1016/S0550-3213(99)00195-9 PG 9 WC Physics, Particles & Fields SC Physics GA 210WM UT WOS:000081127700002 ER PT J AU Dziarmaga, J Laguna, P Zurek, WH AF Dziarmaga, J Laguna, P Zurek, WH TI Symmetry breaking with a slant: Topological defects after an inhomogeneous quench SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERFLUID HE-3; TRANSITIONS; STRINGS AB We show that in second-order phase transformations that are induced by an inhomogeneous quench the density of topological defects is drastically suppressed as the velocity with which the quench propagates falls below a threshold velocity. This threshold is approximately given by the ratio of the healing length to relaxation time at freeze-out, which is the instant when the critical slowing down results in a transition from the adiabatic to the impulse behavior of the order parameter. C1 Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Penn State Univ, CGPG, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Dziarmaga, J (reprint author), Jagiellonian Univ, Inst Phys, Reymonta 4, PL-30059 Krakow, Poland. NR 11 TC 60 Z9 60 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 JUN 14 PY 1999 VL 82 IS 24 BP 4749 EP 4752 DI 10.1103/PhysRevLett.82.4749 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300004 ER PT J AU Hewett, JL AF Hewett, JL TI Indirect collider signals for extra dimensions SO PHYSICAL REVIEW LETTERS LA English DT Article AB A recent suggestion that quantum gravity becomes strong near the weak scale can be probed by the exchange of Kaluza Klein towers of massive gravitons in fermion pair production in e(+)e(-) annihilation and in Drell-Yan production, including contributions from gluon-gluon fusion, at hadron colliders. These processes are found to provide strong bounds which are essentially independent of the number of extra dimensions. We also demonstrate that angular distributions provide a smoking gun signal for low-scale quantum gravity which cannot be mimicked by other new physics scenarios. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Hewett, JL (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 26 TC 388 Z9 388 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 JUN 14 PY 1999 VL 82 IS 24 BP 4765 EP 4768 DI 10.1103/PhysRevLett.82.4765 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300008 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chang, SM 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 Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM 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 Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmonov, D Karmgard, D Kehoe, R Kelly, ML Kim, SK Kilma, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzindki, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Loken, SC Lucotte, A Leuking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oliveira, E Oltman, E Oshima, N Owen, D Padley, P Para, A Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chang, SM 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 Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM 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 Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmonov, D Karmgard, D Kehoe, R Kelly, ML Kim, SK Kilma, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzindki, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Loken, SC Lucotte, A Leuking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oliveira, E Oltman, E Oshima, N Owen, D Padley, P Para, A Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Y Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Measurement of the high-mass Drell-Yan cross section and limits on quark-electron compositeness scales SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARTON DISTRIBUTIONS; PARITY VIOLATION; COLLISIONS; EVENTS; ENERGY; HERA AB We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb(-1) of data collected in p (p) over bar, collisions at root s = 1.8TeV by the D0 Collaboration during 1992-1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1 TeV depending on the assumed form of the effective contact interaction. C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio De Janeiro, Rio De Janeiro, Brazil. Univ Los Andes, Bogota, Colombia. CEA, DAPNIA, Serv Phys Particules, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Arizona, Tucson, AZ 85721 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Oklahoma City, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), NYU, New York, NY 10003 USA. RI Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Sznajder, Andre/L-1621-2016; Belyaev, Alexander/F-6637-2015; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Leflat, Alexander/D-7284-2012; Dudko, Lev/D-7127-2012; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013 OI Kim, Sun Kee/0000-0002-0013-0775; Sznajder, Andre/0000-0001-6998-1108; Baarmand, Marc/0000-0002-9792-8619; Belyaev, Alexander/0000-0002-1733-4408; Aihara, Hiroaki/0000-0002-1907-5964; Dudko, Lev/0000-0002-4462-3192; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; NR 22 TC 70 Z9 71 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 JUN 14 PY 1999 VL 82 IS 24 BP 4769 EP 4774 DI 10.1103/PhysRevLett.82.4769 PG 6 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300009 ER PT J AU Hattass, M Schenkel, T Hamza, AV Barnes, AV Newman, MW McDonald, JW Niedermayr, TR Machicoane, GA Schneider, DH AF Hattass, M Schenkel, T Hamza, AV Barnes, AV Newman, MW McDonald, JW Niedermayr, TR Machicoane, GA Schneider, DH TI Charge equilibration time of slow, highly charged ions in solids SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY-LOSS; AMORPHOUS-CARBON; HEAVY-IONS; L-SHELL; AUGER; FILMS AB We report observations of nonequilibrium charge state distributions of slow, highly charged (33+ less than or equal to q less than or equal to 75+) ions after transmission of thin carbon foils. Charge equilibration times are determined directly from the dependencies of exit charge states on projectile velocity (0.5 X 10(6) < v < 10(6) m/s) and foil thickness (5-10 nm). Ions like Xe44+ and Au68+ are found to equilibrate inside of solid matter in a time of only 7 fs. C1 Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94550 USA. Johannes Gutenberg Univ Mainz, Inst Kernphys, D-60486 Frankfurt, Germany. Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Paris 06, Lab Phys Atom & Nucl, F-75005 Paris, France. RP Hattass, M (reprint author), Lawrence Livermore Natl Lab, Phys & Space Technol Directorate, Livermore, CA 94550 USA. NR 31 TC 56 Z9 64 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 JUN 14 PY 1999 VL 82 IS 24 BP 4795 EP 4798 DI 10.1103/PhysRevLett.82.4795 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300015 ER PT J AU Reboredo, FA Ferconi, M Pantelides, ST AF Reboredo, FA Ferconi, M Pantelides, ST TI Theory of the nucleation, growth, and structure of hydrogen-induced extended defects in silicon SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-CRYSTAL SILICON; DIFFUSION; COMPLEXES AB Implantation and plasma indiffusion of H in crystalline Si are known to induce planar defects (platelets) whose structure has remained elusive. We report extensive first-principles calculations that reveal mechanisms for the nucleation and,growth of aggregates of second-neighbor hydrogenated vacancies. These defects exhibit the key features associated with platelets, including a preference for (111) and (100) planes, H release, and trapping of H-2 molecules. [S0031-9007(99)09314-X]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Reboredo, FA (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Reboredo, Fernando/B-8391-2009 NR 15 TC 58 Z9 59 U1 0 U2 10 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 JUN 14 PY 1999 VL 82 IS 24 BP 4870 EP 4873 DI 10.1103/PhysRevLett.82.4870 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300034 ER PT J AU Yeom, HW Takeda, S Rotenberg, E Matsuda, I Horikoshi, K Schaefer, J Lee, CM Kevan, SD Ohta, T Nagao, T Hasegawa, S AF Yeom, HW Takeda, S Rotenberg, E Matsuda, I Horikoshi, K Schaefer, J Lee, CM Kevan, SD Ohta, T Nagao, T Hasegawa, S TI Instability and charge density wave of metallic quantum chains on a silicon surface SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI(111)4X1-IN SURFACE; PHOTOEMISSION; TRANSITION; CONDUCTOR AB Self-assembled indium linear chains on the Si(lll) surface are found to exhibit instability of the metallic phase and 1D charge density wave (CDW). The room-temperature metallic phase of these chains undergoes a temperature-induced, reversible transition into a semiconducting phase. The 1D CDW along the chains is observed directly in real space by scanning tunneling microscopy at low temperature. The Fermi contours of the metallic phase measured by angle-resolved photoemission exhibit a perfect nesting predicting precisely the CDW periodicity. [S0031-9007(99)09330-8]. C1 Univ Tokyo, Res Ctr Spectrochem, Tokyo 1130033, Japan. Univ Tokyo, Dept Phys, Tokyo 1130033, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Tokyo, Dept Chem, Tsukuba, Ibaraki 3050801, Japan. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. RP Yeom, HW (reprint author), Univ Tokyo, Dept Appl Chem, KEK PF, 1-1 Oho, Tsukuba, Ibaraki 3050801, Japan. RI Rotenberg, Eli/B-3700-2009; Hasegawa, Shuji/F-8059-2010; Takeda, Sakura/B-3101-2011; Kevan, Stephen/F-6415-2010; NAGAO, Tadaaki/H-2582-2011 OI Rotenberg, Eli/0000-0002-3979-8844; Kevan, Stephen/0000-0002-4621-9142; NR 23 TC 395 Z9 396 U1 4 U2 60 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 JUN 14 PY 1999 VL 82 IS 24 BP 4898 EP 4901 DI 10.1103/PhysRevLett.82.4898 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300041 ER PT J AU Sonier, JE Hundley, MF Thompson, JD Brill, JW AF Sonier, JE Hundley, MF Thompson, JD Brill, JW TI Low field anomaly in the specific heat of s-wave superconductors due to the expansion of the vortex cores SO PHYSICAL REVIEW LETTERS LA English DT Article ID TEMPERATURE SPECIFIC-HEAT; DENSITY-OF-STATES; DEPENDENCE; LINES AB The magnetic field dependence of the electronic specific heat C(H) in the s-wave superconductor NbSe2 shows curvature at low fields, resembling the near root H term in C(H) which has been reported in high-T-c superconductors and attributed to a d(x2-y2)-wave pairing state. In NbSe2 we find that the low field behavior in C(H) is described quantitatively by the expansion of vortex cores and the field dependence of the magnetic induction B above H-c1. The associated change in the density of quasiparticle states localized in the vortex cores provides a simple explanation for the "low field anomaly" in C(H) observed in s-wave superconductors. [S0031-9007(99)09363-1]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. RP Sonier, JE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 23 TC 66 Z9 66 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 14 PY 1999 VL 82 IS 24 BP 4914 EP 4917 DI 10.1103/PhysRevLett.82.4914 PG 4 WC Physics, Multidisciplinary SC Physics GA 205CT UT WOS:000080804300045 ER PT J AU Bergara, A Pitarke, JM Ritchie, RH AF Bergara, A Pitarke, JM Ritchie, RH TI Plasmon excitation by charged particles interacting with metal surfaces SO PHYSICS LETTERS A LA English DT Article ID ELECTRON-EMISSION; IONS; SOLIDS; AL AB Recent experiments (R.A. Baragiola and C.A. Dukes, Phys. Rev. Lett. 76 (1996) 2547) with slow ions incident at grazing angle on metal surfaces have shown that bulk plasmons are excited under conditions where the ions do not penetrate the surface, contrary to the usual statement that probes exterior to an electron gas do not couple to the bulk plasmon. We here use the quantized hydrodynamic model of the bounded electron gas to derive an explicit expression for the probability of bulk plasmon excitation by external charged particles moving parallel to the surface. Our results indicate that for each q (the surface plasmon wave vector) there exists a continuum of bulk plasmon excitations, which we also observe within the semi-classical infinite-barrier (SCIB) model of the surface. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Euskal Herriko Unibertsitea, Zientzi Fak, Mat Kondentsatuaren Fis Saila, Bilbao 48080, Basque Country, Spain. Donostia Int Phys Ctr, E-20018 Donostia San Sebastian, Basque Country, Spain. CSIC, Ctr Mixto, UPV EHU, E-48080 Bilbao, Basque Country, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Bergara, A (reprint author), Euskal Herriko Unibertsitea, Zientzi Fak, Mat Kondentsatuaren Fis Saila, 644 Posta Kutzatila, Bilbao 48080, Basque Country, Spain. RI Pitarke, Jose/C-8602-2009; DONOSTIA INTERNATIONAL PHYSICS CTR., DIPC/C-3171-2014; Bergara, Aitor/G-2434-2016; CSIC-UPV/EHU, CFM/F-4867-2012 OI Pitarke, Jose/0000-0002-8253-8028; NR 27 TC 15 Z9 15 U1 0 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 EI 1873-2429 J9 PHYS LETT A JI Phys. Lett. A PD JUN 14 PY 1999 VL 256 IS 5-6 BP 405 EP 410 DI 10.1016/S0375-9601(99)00264-9 PG 6 WC Physics, Multidisciplinary SC Physics GA 209AE UT WOS:000081024200016 ER PT J AU Liu, Q Jin, CW Liao, XB Shen, ZY Chen, DJ Chen, Y AF Liu, Q Jin, CW Liao, XB Shen, ZY Chen, DJ Chen, Y TI The binding interface between an E2 (UBC9) and a ubiquitin homologue (UBL1) SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID CONJUGATING ENZYME; CRYSTAL-STRUCTURE; SACCHAROMYCES-CEREVISIAE; ANGSTROM RESOLUTION; PROTEIN; SYSTEM; GENE; IDENTIFICATION; DEGRADATION; MODIFIER AB Human UBC9 is a member of the E2 (ubiquitin conjugation enzyme) family of proteins. Instead of conjugating to ubiquitin, it conjugates with a ubiquitin homologue UBL1 (also known as SUMO-1, GMP1, SMTP3, PIC1, and sentrin). UBC9 has been shown to be involved in cell cycle regulation, DNA repair, and p53-dependent processes. The binding interfaces of the UBC9 and UBL1 complex have been determined by chemical shift perturbation using nuclear magnetic resonance spectroscopy. The binding site of UBL1 resides on the ubiquitin domain, and the binding site of UBC9 is located on a structurally conserved region of E2, Because the UBC9-UBL1 system shares many similarities with the ubiquitin system in structures and in conjugation with each other and with target proteins, the observed binding interfaces may be conserved in Ea-ubiquitin interactions in general. C1 City Hope Natl Med Ctr, Beckman Res Inst, Div Immunol, Duarte, CA 91010 USA. Univ Illinois, Dept Biochem & Mol Biol, Chicago, IL 60612 USA. Univ Illinois, Ctr Canc, Chicago, IL 60607 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, DNA Damage & Repair Grp, Los Alamos, NM 87545 USA. RP Chen, Y (reprint author), City Hope Natl Med Ctr, Beckman Res Inst, Div Immunol, 1450 E Duarte Rd, Duarte, CA 91010 USA. FU NIGMS NIH HHS [GM54190] NR 31 TC 70 Z9 70 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 JUN 11 PY 1999 VL 274 IS 24 BP 16979 EP 16987 DI 10.1074/jbc.274.24.16979 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 204TL UT WOS:000080780400046 PM 10358047 ER PT J AU Burma, S Kurimasa, A Xie, GF Taya, Y Araki, R Abe, M Crissman, HA Ouyang, H Li, GC Chen, DJ AF Burma, S Kurimasa, A Xie, GF Taya, Y Araki, R Abe, M Crissman, HA Ouyang, H Li, GC Chen, DJ TI DNA-dependent protein kinase-independent activation of p53 in response to DNA damage SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID IONIZING-RADIATION; CATALYTIC SUBUNIT; PHOSPHORYLATION; CELLS; CHECKPOINTS; EXPRESSION; MICE AB Phosphorylation at serine 15 of the human p53 tumor suppressor protein is induced by DNA damage and correlates with accumulation of p53 and its activation as a transcription factor. The DNA-dependent protein kinase (DNA-PK) can phosphorylate serine 15 of human p53 and the homologous serine 18 of murine p53 in vitro, Contradictory reports exist about the requirement for DNA-PK in vivo for p53 activation and cell cycle arrest in response to ionizing radiation. While primary SCID (severe combined immunodeficiency) cells, that have defective DNA-PK, show normal p53 activation and cell cycle arrest, a transcriptionally inert form of p53 is induced in the SCID cell line SCGR11. In order to unambiguously define the role of the DNA-PK catalytic subunit (DNA-PKcs) in p53 activation, we examined p53 phosphorylation in mouse embryonic fibroblasts (MEFs) from DNA-PKcs-null mice. We found a similar pattern of serine 18 phosphorylation and accumulation of p53 in response to irradiation in both control and DNA-PKcs-null MEFs, The induced p53 was capable of sequence-specific DNA binding even in the absence of DNA-PKcs. Transactivation of the cyclin-dependent-kinase inhibitor p21, a downstream target of p53, and the G(1) cell cycle checkpoint were also found to be normal in the DNA-PKcs -/- MEFs. Our results demonstrate that DNA-PKcs, unlike the related ATM protein, is not essential for the activation of p53 and G(1) cell cycle arrest in response to ionizing radiation. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Natl Canc Ctr, Res Inst, Tokyo 1040045, Japan. Natl Inst Radiol Sci, Chiba 2638555, Japan. Mem Sloan Kettering Canc Ctr, New York, NY 10021 USA. RP Chen, DJ (reprint author), Lawrence Berkeley Natl Lab, Div Life Sci, MS 74,1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-50519, CA-56909, CA078497] NR 25 TC 65 Z9 67 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUN 11 PY 1999 VL 274 IS 24 BP 17139 EP 17143 DI 10.1074/jbc.274.24.17139 PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 204TL UT WOS:000080780400068 PM 10358069 ER PT J AU Sanati, M Saxena, A AF Sanati, M Saxena, A TI Half-kink lattice solution of the phi(6) model SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID PHASE-TRANSITION; TRANSFORMATION; NI2MNGA AB Investigation of a great number of physical systems shows that a scaled Landau free energy density of the form F(phi) = a/2 phi(2) - 1/4 phi(4) + 1/6 phi(6) describes a first-order phase transition. To study the formation of static domain walls in these systems we include a spatial gradient (Ginzburg) term of the scalar order parameter phi. At the transition temperature (T-c) the potential has three degenerate minima corresponding to an asymmetric domain wall (i.e. a half-kink solution). We have obtained the associated kink lattice solution, its energy of formation and asymptotic kink-kink interaction. In addition, we report a 'pulse' lattice solution below T-c. C1 Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Sanati, M (reprint author), Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. NR 18 TC 9 Z9 9 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD JUN 11 PY 1999 VL 32 IS 23 BP 4311 EP 4320 DI 10.1088/0305-4470/32/23/309 PG 10 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 207EW UT WOS:000080924000010 ER PT J AU Kim, KJ AF Kim, KJ TI The equation of motion of an electron: a debate in classical and quantum physics SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC AB The current status of understanding of the equation of motion of an electron is summarized. Classically, a consistent, linearized theory exists for an electron of finite extent, as long as the size of the electron is larger than the classical electron radius. Nonrelativistic quantum mechanics seems to offer a fine theory even in the point-particle limit. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Chicago, Chicago, IL 60637 USA. RP Kim, KJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 0 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 1 EP 8 DI 10.1016/S0168-9002(99)00047-9 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900002 ER PT J AU Urbanus, WH Bongers, WA van der Geer, CAJ Manintveld, P Plomp, J Pluygers, J Poelman, AJ Smeets, PHM Schuller, FC Verhoeven, AGA Bratman, VL Denisov, GG Savilov, AV Shmelyov, MY Caplan, M Varfolomeev, AA AF Urbanus, WH Bongers, WA van der Geer, CAJ Manintveld, P Plomp, J Pluygers, J Poelman, AJ Smeets, PHM Schuller, FC Verhoeven, AGA Bratman, VL Denisov, GG Savilov, AV Shmelyov, MY Caplan, M Varfolomeev, AA TI First lasing of the Dutch Fusion-FEM: 730 kW, 200 GHz SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE maser; FEM; electron beam mm-waves ID BEAM AB A high-power electrostatic free-electron maser is operated at various frequencies. An output power of 730 kW at 206 GHz is generated with a 7.2 Al 1.77 MeV electron beam, and 360 kW at 167 GHz is generated with a 7.0 A, 1.61 MeV electron beam. It is shown experimentally and by simulations that, depending on the electron beam energy, the FEM can operate in single-frequency regime. First experiments were done without electron beam energy recovery system, and the pulse length was limited to 12 mu s. Nevertheless, many aspects of generation of mm-wave power have been explored, such as the dependency on the electron beam energy and beam current and cavity settings such as the feedback coefficient. The achieved parameters and the FEM dynamics are in good accordance with simulations. (C) 1999 Elsevier Science B.V. All rights reserved. C1 EURATOM Assoc, FOM, Inst Plasmafys Rijnhuizen, NL-3430 BE Nieuwegein, Netherlands. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603600, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Kurchatov Inst, Russian Res Ctr, Moscow 123182, Russia. RP Urbanus, WH (reprint author), EURATOM Assoc, FOM, Inst Plasmafys Rijnhuizen, POB 1207, NL-3430 BE Nieuwegein, Netherlands. NR 6 TC 5 Z9 5 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 12 EP 16 DI 10.1016/S0168-9002(99)00052-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900004 ER PT J AU Benson, S Biallas, G Bohn, C Douglas, D Dylla, HF Evans, R Fugitt, J Hill, R Jordan, K Krafft, G Legg, R Li, R Merminga, L Neil, GR Oepts, D Piot, P Preble, J Shinn, M Siggins, T Walker, R Yunn, B AF Benson, S Biallas, G Bohn, C Douglas, D Dylla, HF Evans, R Fugitt, J Hill, R Jordan, K Krafft, G Legg, R Li, R Merminga, L Neil, GR Oepts, D Piot, P Preble, J Shinn, M Siggins, T Walker, R Yunn, B TI First lasing of the Jefferson Lab IR Demo FEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE lasing; free-electron laser; recirculation AB As reported in previous work (Neil, Proceedings of the 1998 European Particle Accelerator Conference, Stockholm, Sweden, 1998, p. 88; Shinn, in: Free-Electron Laser Challenges, Proceedings of SPIE, vol. 2988, 1997, p. 170), Jefferson Lab is building a free-electron laser capable of generating a continuous wave kilowatt laser beam. The driver-accelerator consists of a superconducting, energy-recovery accelerator. The initial stage of the program was to produce over 100 W of average power with no recirculation. In order to provide maximum gain the initial wavelength was chosen to be 5 mu m and the initial beam energy was chosen to be 38.5 MeV. On June 17. 1998, the laser produced 155 W cw power at the laser output with a 98% reflective output coupler. On July 28th, 311 W cw power was obtained using a 90% reflective output coupler. A summary of the commissioning activities to date as well as some novel lasing results will be summarized in this paper. Present work is concentrated on optimizing lasing at 5 mu m, obtaining lasing at 3 mu m, and commissioning the recirculation transport in preparation for kilowatt lasing this fall. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Benson, S (reprint author), Thomas Jefferson Natl Accelerator Facil, 12000 Jefferson Ave, Newport News, VA 23606 USA. OI EVANS, ROBIN/0000-0002-7988-3189 NR 13 TC 27 Z9 28 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 27 EP 32 DI 10.1016/S0168-9002(99)00061-3 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900007 ER PT J AU Merminga, L Alexeev, P Benson, S Bolshakov, A Doolittle, L Neil, G AF Merminga, L Alexeev, P Benson, S Bolshakov, A Doolittle, L Neil, G TI Analysis of the FEL-RF interaction in recirculating, energy-recovering linacs with an FEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE FEL-RF interactions; beam-cavity interaction; electron-photon beam interaction AB Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, phase oscillations and optical cavity detuning. These effects in turn cause changes in the laser output power through a time-varying FEL gain function. All three effects change the beam-induced voltage in the cavities and can lead to unstable variations of the accelerating field and output laser power. We have developed a model of the coupled system and solved it both analytically and numerically. It includes the beam-cavity interaction, low level RF feedback, and the electron-photon interaction. The latter includes the FEL gain function in terms of cavity detuning, energy offset, and is valid both in the small signal gain and in the saturated regimes. We have demonstrated that in the limit of small perturbations, the linear theory agrees with the numerical solutions and have performed numerical simulations for the IR FEL presently being commissioned at Jefferson Lab. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Merminga, L (reprint author), Thomas Jefferson Natl Accelerator Facil, MS 58,12000 Jefferson Ave, Newport News, VA 23606 USA. NR 7 TC 11 Z9 12 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 58 EP 64 DI 10.1016/S0168-9002(99)00067-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900013 ER PT J AU Freund, HP Tatchyn, R AF Freund, HP Tatchyn, R TI Collective effects in short wavelength free-electron lasers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE free-electron lasers; one-dimensional theory ID MAGNETIC-FIELD AB The self-fields generated by the propagation of pulsed electron beams through the wiggler fields in free-electron lasers are calculated and shown to be diamagnetic. A one-dimensional theory for pulsed beams is applied to proposed designs for fourth generation light sources of high-intensity X-rays, which employ beams with current densities of several hundred MA/cm(2). The theory indicates that the diamagnetic effect is unlikely to affect either the growth length or the fundamental emission energy and bandwidth of these devices. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Sci Applicat Int Corp, Mclean, VA 22102 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Freund, HP (reprint author), Sci Applicat Int Corp, 1710 Goodridge Dr, Mclean, VA 22102 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 76 EP 81 DI 10.1016/S0168-9002(99)00073-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900016 ER PT J AU Taccetti, JM Jackson, RH Freund, HP Pershing, DE Granatstein, VL AF Taccetti, JM Jackson, RH Freund, HP Pershing, DE Granatstein, VL TI A Ka-band CHI-wiggler free-electron maser: experimental results SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE coaxial; wiggler; microwaves; free-electron maser; small-period wigglers AB Due to the nature of the Coaxial Hybrid Iron wiggler, a resonance between the transverse wiggler and cyclotron motions of the beam exists which can enhance the Free-Electron Maser interaction. The difference in behavior on either side of this resonance is presented. Amplification with a bandwidth on the order of a few percent was achieved. In spite of beam propagation problems, the gain was about 5 dB for operation below gyroresonance, and 7 dB above it, when wideband grazing intersection operation was achieved. A gain as high as 13.5 dB was obtained for cutting intersection between the beam line and the TE01 dispersion curve. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. USN, Res Lab, Washington, DC 20375 USA. Sci Applicat Int Corp, Mclean, VA 22102 USA. MRC, Newington, VA 22122 USA. Univ Maryland, College Pk, MD 20742 USA. RP Taccetti, JM (reprint author), Univ Calif Los Alamos Natl Lab, MS E526, Los Alamos, NM 87545 USA. NR 6 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 116 EP 120 DI 10.1016/S0168-9002(99)00083-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900023 ER PT J AU Nguyen, DC Sheffield, RL Fortgang, CM Goldstein, JC Kinross-Wright, JM Ebrahim, NA AF Nguyen, DC Sheffield, RL Fortgang, CM Goldstein, JC Kinross-Wright, JM Ebrahim, NA TI First lasing of the regenerative amplifier FEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE regenerative amplifier; high-gain; SASE; high power; RF-linac FEL; Cs2Te; photocathode ID AVERAGE-POWER FEL AB The regenerative amplifier free-electron laser (RAFEL) is a high-gain RF-linac FEL capable of producing high optical power from a compact design. The combination of a high-gain and small optical feedback enables the FEL to reach saturation and produce a high optical power and high extraction efficiency without the risk of optical damage to the mirrors. This paper summarizes the first lasing of the regenerative amplifier FEL and describes recent experimental results. The highest optical energy achieved thus far at 16.3 mu m is 1.7 J over a train of 900 micropulses. We infer pulse energy of 1.9 mJ in each 16 ps micropulse, corresponding to a peak power of 120 MW. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nguyen, DC (reprint author), Univ Calif Los Alamos Natl Lab, MS H851, Los Alamos, NM 87545 USA. NR 6 TC 23 Z9 23 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 125 EP 130 DI 10.1016/S0168-9002(99)00090-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900025 ER PT J AU Tremaine, A Rosenzweig, J Anderson, S Frigola, P Hogan, M Murokh, A Pellegrini, C Nguyen, D Sheffield, R AF Tremaine, A Rosenzweig, J Anderson, S Frigola, P Hogan, M Murokh, A Pellegrini, C Nguyen, D Sheffield, R TI Measured free-electron laser microbunching using coherent transition radiation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE CTR; FEL wavelength; microbunching; scattering effects ID BEAM; ACCELERATOR AB The microbunch distribution of an electron beam exiting a SASE free-electron laser has been measured using the emitted coherent transition radiation (CTR) produced from a thin aluminum foil placed at the end of the undulator. The wavelength of the coherent transition radiation is shown to be the same as the FEL wavelength, and thus a measure of the beam microbunch spacing. Also, the study of the CTR linewidth and angular acceptance of the radiation captured are shown to be derived from this coherent radiative process. Scattering effects on the forward emitted transition radiation from the electron beam traversing an aluminum foil are also considered. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Tremaine, A (reprint author), Univ Calif Los Angeles, 405 Higard Ave, Los Angeles, CA 90095 USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 209 EP 212 DI 10.1016/S0168-9002(99)00105-9 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900039 ER PT J AU Yu, LH AF Yu, LH TI Power spectrum calculation for the Cornell Wiggler A SASE experiment at BNL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE power spectrum; simulation code; SASE; coupling coefficient ID FREE-ELECTRON-LASER; AMPLIFIED SPONTANEOUS EMISSION; OUTPUT POWER; SIMULATION AB Recently, we showed (Yu, Phys. Rev. E 58 (1998) 4991) that the widely used simulation code TDA3D, even though a single-frequency code, can be used to determine the power spectrum in the SASE process with excellent approximation in the exponential growth regime. In this paper, we apply this method to the BNL Cornell Wiggler A SASE experiment as an example. When the gain is not very high, there are many modes in the radiation, which seems to make the analytical calculation very difficult. However, we show that the increment of the radiation due to SASE over the spontaneous radiation can be expanded in terms of guided modes with rapid convergence. Thus when the spontaneous radiation is subtracted from the SASE power during the calculation, there is a good agreement between the analytical theory and the numerical simulation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Yu, LH (reprint author), Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 213 EP 218 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900040 ER PT J AU Dejus, RJ Shevchenko, OA Vinokurov, NA AF Dejus, RJ Shevchenko, OA Vinokurov, NA TI An integral equation based computer code for high-gain free-electron lasers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE free-electron laser; simulation AB A computer code for gain optimization of high-gain free-electron lasers (FELs) is described. The electron motion is along precalculated period-averaged trajectories, and the finite-emittance electron beam is represented by a set of thin "partial" beams. The radiation field amplitudes are calculated at these thin beams only. The system of linear integral equations for these field amplitudes and the Fourier harmonics of the current of each thin beam is solved numerically. The code is aimed for design optimization of high-gain short-wavelength FELs with nonideal magnetic systems (breaks between undulators with quadrupoles and magnetic bunchers; field and steering errors). Both self-amplified spontaneous emission (SASE) and external input signal options can be treated. A typical run for a UV FEL, several gain lengths long, takes only 1 min on a Pentium II personal computer (333 MHz), which makes it possible to run the code in optimization loops. Results for the Advanced Photon Source FEL project are presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. RP Dejus, RJ (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 8 TC 10 Z9 10 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 225 EP 228 DI 10.1016/S0168-9002(99)00108-4 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900042 ER PT J AU Nuhn, HD AF Nuhn, HD TI FEL simulations for the LCLS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE FEL simulations; LCLS; GINGER ID FREE-ELECTRON LASERS AB A first design study report has recently been completed (The LCLS Design Study Group, LCLS Design Study Report, April 1998, SLAC-R-521) for the linac coherent light source (LCLS), a proposal to build an X-ray free electron laser (FEL) at the Stanford Linear Accelerator Center (SLAC) as a single pass self-amplified spontaneous emission (SASE) amplifier. The proposal includes the use of a very low emittance electron beam accelerated up to 15 GeV by the last third of the SLAC linac to produce sub-picosecond X-ray pulses with high brightness and full transverse coherence in a 112-m long undulator. Many aspects of the FEL design have been analyzed with FEL simulation codes. The paper discusses some of the results of these aspects, i.e. temporal X-ray pulse structure and power spectrum, trajectory errors and effects of undulator beam tube wakefields. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Nuhn, HD (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 12 TC 7 Z9 7 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 249 EP 256 DI 10.1016/S0168-9002(99)00116-3 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900047 ER PT J AU Lumpkin, AH Yang, BX AF Lumpkin, AH Yang, BX TI Potential diagnostics for the next-generation light sources SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE diagnostics; SASE; FEL; spatial resolution; X-ray streak camera; undulator AB There is continued interest in developing a diffraction-limited soft or hard X-ray source. Candidate paths include the storage-ring-based free-electron laser (FEL) and the linac-based self-amplified spontaneous emission (SASE) FEL for the two regimes, respectively. As previously discussed, target beam parameters are sigma(x,y) similar to 10 mu m, sigma(x',y') = 1 mu rad, and sigma(t) similar to 1 ps (0.1 ps for the linac case). We report the use of few- to sub-angstrom radiation emitted by a 7-GeV beam transitting a 198-period diagnostics undulator and a bending magnet to characterize the particle beam. A particle beam divergence as low as sigma(y') = 3.3 mu rad was measured using an X-ray monochromator. Additionally, a particle beam size of sigma(y) < 45 mu m and a bunch length of sigma(t) = 28 ps with 4-ps resolution were measured using an X-ray pinhole camera with a unique synchroscan and dual-sweep X-ray streak camera as the detector. The adjustable pinhole aperture was varied by more than a factor of 100 to assess spatial resolution and dynamic range issues in the system. These diagnostics demonstrations should scale to next-generation applications. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Lumpkin, AH (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 293 EP 298 DI 10.1016/S0168-9002(99)00130-8 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900054 ER PT J AU Li, R AF Li, R TI Self-consistent simulation of the CSR effect on beam emittance SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE microbunch; curved trajectory; space-charge forces AB When a microbunch with high charge traverses a curved trajectory, the curvature-induced Coherent Synchrotron Radiation (CSR) and space-charge forces may cause serious emittance degradation. Earlier analyses based on rigid-line charge model are helpful in understanding the mechanism of this curvature-induced bunch self-interaction. In reality, however, the bunch has finite transverse size and its dynamics respond to the CSR ford. In this paper, we present the first self-consistent simulation for the study of the impact of CSR on beam optics. With the bunch represented by a set of macroparticles, the dynamics of the bunch under the influence of the CSR force are simulated, where the CSR force in turn depends on the history of bunch charge distribution and current density in accordance to causality. This simulation is bench-marked with previous analytical results for a rigid-line bunch. The algorithm applied in the simulation will be presented, along with the simulation results obtained for bending systems in the Jefferson Lab FEL lattice. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Li, R (reprint author), Thomas Jefferson Natl Accelerator Facil, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 7 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1999 VL 429 IS 1-3 BP 310 EP 314 DI 10.1016/S0168-9002(99)00135-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900057 ER PT J AU Alley, R Bharadwaj, V Clendenin, J Emma, P Fisher, A Frisch, J Kotseroglou, T Miller, RH Palmer, DT Schmerge, J Sheppard, JC Woodley, M Yeremian, AD Rosenzweig, J Meyerhofer, DD Serafini, L AF Alley, R Bharadwaj, V Clendenin, J Emma, P Fisher, A Frisch, J Kotseroglou, T Miller, RH Palmer, DT Schmerge, J Sheppard, JC Woodley, M Yeremian, AD Rosenzweig, J Meyerhofer, DD Serafini, L TI The design for the LCLS RF photoinjector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE RF photoinjector; Linac coherent light source ID PULSES; GUN AB We report on the design of the RF photoinjector of the Linac Coherent Light Source. The RF photoinjector is required to produce a single 150 MeV bunch of similar to 1 nC and similar to 100 A peak current at a repetition rate of 120 Hz with a normalized rms transverse emittance of similar to 1 pi mm-mrad. The design employs a 1.6-cell S-band RF gun with an optical spot size at the cathode of a radius of similar to 1 mm and a pulse duration with an rms sigma of similar to 3 ps. The peak RF field at the cathode is 150 MV/m with extraction 57 degrees ahead of the RF peak. A solenoidal field near the cathode allows the compensation of the initial emittance growth by the end of the injection linac. Spatial and temporal shaping of the laser pulse striking the cathode will reduce the compensated emittance even further. Also, to minimize the contribution of the thermal emittance from the cathode surface, while at the same time optimizing the quantum efficiency, the laser wavelength for a Cu cathode should be tunable around 260 nm. Following the injection linac the geometric emittance simply damps linearly with energy growth. PARMELA simulations show that this design will produce the desired normalized emittance, which is about a factor of two lower than has been achieved to date in other systems. In addition to low emittance, we also aim for laser amplitude stability of 1% in the UV and a timing jitter in the electron beam of 0.5 ps rms, which will lead to less than 10% beam intensity fluctuation after the electron bunch is compressed in the main linac. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Calif Los Angeles, Los Angeles, CA USA. Univ Rochester, Dept Mech Engn, Dept Phys & Astron, Rochester, NY 14627 USA. Univ Milan, Ist Nazl Fis Nucl, Milan, Italy. RP Kotseroglou, T (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 11 TC 7 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 324 EP 331 DI 10.1016/S0168-9002(99)00072-8 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900060 ER PT J AU Lumpkin, AH Yang, BX Berg, WJ White, M Lewellen, JW Milton, SV AF Lumpkin, AH Yang, BX Berg, WJ White, M Lewellen, JW Milton, SV TI Optical techniques for electron-beam characterizations on the APS SASE FEL project SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE APS; OTR; YAG crystal; RF thermionic gun; beam size; bunch length AB At the Advanced Photon Source (APS) the injector linac's DC thermionic gun is being supplemented by a low-emittance RF thermionic gun that will support the SASE FEL project. To address the anticipated smaller beam sizes, the standard Chromox beam-profiling screens are being complemented by optical transition radiation (OTR) and Ce-doped YAG single-crystal converters. Direct comparisons of the effective conversion efficiency, spatial resolution, and time response of the three converter screen types have been performed using the DC thermionic gun's beam accelerated to 400-650 MeV. An apparent blurring of observed beam size with increasing incident charge areal density in the YAG crystal was observed for the first time. Only the OTR was prompt enough for the few-ps domain micropulse bunch length measurements performed with a streak camera. Initial beam images of the RF-thermionic gun beam have also been obtained. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Lumpkin, AH (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. NR 8 TC 22 Z9 23 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 336 EP 340 DI 10.1016/S0168-9002(99)00075-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900062 ER PT J AU Reis, DA Hernandez, M Schmerge, JF Winick, H Hogan, MJ AF Reis, DA Hernandez, M Schmerge, JF Winick, H Hogan, MJ TI Transverse emittance measurements from a photocathode RF gun with variable laser pulse length SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE GTF; photocathode; RF gun; LCLS AB The gun test facility (GTF) at SSRL was started in 1996 to develop an appropriate injector for the proposed linac coherent light source (LCLS) at SLAG. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1 pi mm mrad normalized rms emittance. The photoinjector at the GTF is 1.6 cell S-band symmetrized gun and emittance compensation solenoid. Emittance measurements, reported here, were made as function of laser pulse width using Gaussian longitudinal pulses. The lowest achieved emittance to date with 1 nC of charge is 5.6 pi mm mrad and was obtained with a pulse width of 5 ps (FWHM) and is in agreement with simulation. There are indications that the accelerator settings for these results may not have been optimal. Simulations also indicate that a normalized emittance meeting the LCLS requirement can be obtained using appropriately shaped transverse and temporal laser/electron beam pulses. Work has begun on producing temporal flat top laser pulses which combined with transverse clipping of the laser is expected to lower the emittance to approximately 1 pi mm mrad for 1 nC with optimal accelerator settings. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. RP Hernandez, M (reprint author), Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Box 4349, Stanford, CA 94309 USA. NR 10 TC 0 Z9 0 U1 1 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 341 EP 346 DI 10.1016/S0168-9002(99)00079-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900063 ER PT J AU Gluskin, E Benson, C Dejus, RJ Den Hartog, PK Deriy, BN Makarov, OA Milton, SV Moog, ER Ogurtsov, VI Trakhtenberg, EM Robinson, KE Vasserman, IB Vinokurov, NA Xu, S AF Gluskin, E Benson, C Dejus, RJ Den Hartog, PK Deriy, BN Makarov, OA Milton, SV Moog, ER Ogurtsov, VI Trakhtenberg, EM Robinson, KE Vasserman, IB Vinokurov, NA Xu, S TI The magnetic and diagnostics systems for the Advanced Photon Source self-amplified spontaneously emitting FEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE free-electron laser ID UNDULATOR AB A self-amplified spontaneously emitting (SASE) free-electron laser (FEL) for the visible-to-ultraviolet spectral range is under construction at the Advanced Photon Source at Argonne National Laboratory. The amplifier part of the FEL consists of twelve identical 2.7-m-long sections. Each section includes a 2.4-m-long, 33-mm-period hybrid undulator, a quadrupole lens, and a set of electron beam and radiation diagnostics equipment. The undulators will operate at a fixed magnetic gap (approx. 9.3 mm) with K = 3.1. The electron beam position will be monitored using capacitive beam position monitors, YAG scintillators with imaging optics, and secondary emission detectors. The spatial distribution of the photon beam will be monitored by position sensitive detectors equipped with narrow-band tilters. A high-resolution spectrograph will be used to observe the spectral distribution of the FEL radiation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. STI Optron, Bellevue, WA 98004 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. RP Moog, ER (reprint author), Argonne Natl Lab, Adv Photon Source, XFD-401,9700 S Cass Ave, Argonne, IL 60439 USA. NR 9 TC 33 Z9 33 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 358 EP 364 DI 10.1016/S0168-9002(99)00087-X PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900066 ER PT J AU Tatchyn, T Arthur, J Boyce, R Fasso, A Montgomery, J Vylet, V Walz, D Yotam, R Freund, AK Howells, M AF Tatchyn, T Arthur, J Boyce, R Fasso, A Montgomery, J Vylet, V Walz, D Yotam, R Freund, AK Howells, M TI X-ray optics design studies for the SLAG 1.5-15 angstrom Linac coherent light source (LCLS) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE X-ray optics design studies; Linac coherent light source; SASE; XRFEL ID FREE-ELECTRON LASERS; CRYSTALS; RADIATION; BEAMS AB In recent years, a number of systematic studies have been carried out on the design and R&D aspects of X-ray free-electron laser (XRFEL) schemes based on driving highly compressed electron bunches from a multi-GeV linac through long (30 m - 100 + m) undulators. These sources, when operated in the self-amplified spontaneous emission (SASE mode, feature singularly high peak output power densities and frequently unprecedented combinations of phase-space and output-parameter values. This has led to correspondingly pivotal design challenges and opportunities for the optical materials, systems, components, and experimental configurations for transporting and utilizing this radiation. In this paper we summarize the design and R&D status of the X-ray optics section of the SLAG Linac Coherent Light Source (LCLS), a 1.5 Angstrom SASE FEL driven by the last kilometer of the SLAG 3-kilometer S-band linac. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Tatchyn, T (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. NR 59 TC 2 Z9 2 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 397 EP 406 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900072 ER PT J AU Emma, P Carr, R Huhn, HD AF Emma, P Carr, R Huhn, HD TI Beam-based alignment for the LCLS FEL undulator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC AB The linac coherent light source (LCLS) (LCLS Design Study Report, SLAC-R-521, 1998) is an X-ray FEL based on a long, permanent magnet undulator comprised of multiple segments which provide space for electron beam position monitors (BPMs) and quadrupole focusing magnets. The 15 GeV electron trajectory within the undulator must be straight to similar to 5 mu m over a gain length of 11 m so that the photon beam overlaps efficiently with the electron beam. This alignment precision is not achievable with available mechanical survey methods. For this reason, an empirical beam-based alignment technique is developed that uses BPM readings in conjunction with large, deliberate variations in the electron energy. We describe here a detailed alignment simulation including BPM and magnet-mover calibration errors, quadrupole gradient errors, and dipole field errors which demonstrate that the alignment can be achieved with high confidence. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Emma, P (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 1 TC 15 Z9 15 U1 2 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 407 EP 413 DI 10.1016/S0168-9002(99)00117-5 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900073 ER PT J AU Tatchyn, R AF Tatchyn, R TI Principles of high-contrast energy modulation and microbunching of electron beams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 20th International Free Electron Laser Conference 5th FEL User Workshop CY AUG 16-22, 1998 CL WILLIAMSBURG, VIRGINIA SP Duke Unvi, Dept of Energy USA, Thomas Jefferson Natl Accelerator Facil, Du Pont, Off Naval Res, SNC DE microbunching; high-contrast modulation; free electron lasers; relativistic interferometry ID LASER AB Recent advancements in ultra-short-pulse terawatt IR/visible/UV laser technology have made it possible to consider particle-beam energy modulation schemes in which the practical field amplitudes of the laser and undulator fields in an ultrarelativistic electron bunch's average rest frame can attain comparable magnitudes. This parameter regime, well outside the radiation field strengths attainable by conventional free electron lasers, makes possible the exploitation of "relativistic interferometry". viz., the phenomenon of high-contrast interference, to isolate regions in the longitudinal space of an electron bunch on the order of one laser wavelength In this paper we review selected requirements on the laser and undulator fields to generate highly efficient microbunching followed by coherent radiation at a substantially reduced wavelength. Conditions on the electron beam quality, as well as selected possibilities for new modes of operation, are summarized. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Tatchyn, R (reprint author), Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 20 TC 2 Z9 2 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 JUN 11 PY 1999 VL 429 IS 1-3 BP 462 EP 470 DI 10.1016/S0168-9002(99)00142-4 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 210WD UT WOS:000081126900083 ER PT J AU Alcock, C Allsman, RA Alves, D Axelrod, TS Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Griest, K King, LJ Lehner, MJ Marshall, SL Minniti, D Peterson, BA Pratt, MR Quinn, PJ Rhie, SH Rodgers, AW Stetson, PB Stubbs, CW Sutherland, W Tomaney, A Vandehei, T AF Alcock, C Allsman, RA Alves, D Axelrod, TS Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Griest, K King, LJ Lehner, MJ Marshall, SL Minniti, D Peterson, BA Pratt, MR Quinn, PJ Rhie, SH Rodgers, AW Stetson, PB Stubbs, CW Sutherland, W Tomaney, A Vandehei, T TI Discovery and characterization of a caustic crossing microlensing event in the Small Magellanic Cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; gravitational lensing; Magellanic Clouds; stars : low-mass, brown dwarfs ID LIMB-DARKENING COEFFICIENTS; SYSTEMS; STARS; HALO AB We present photometric observations and analysis of the second microlensing event detected toward the Small Magellanic Cloud (SMC), MACHO Alert 98-SMC-1. This event was detected early enough to allow intensive observation of the light curve. These observations revealed 98-SMC-1 to be the first caustic crossing binary microlensing event toward the Magellanic Clouds to be discovered in progress. Frequent coverage of the evolving light curve allowed an accurate prediction for the date of the source crossing out of the lens caustic structure. The caustic crossing temporal width, along with the angular size of the source star, measures the proper motion of the lens with respect to the source and thus allows an estimate of the location of the lens. Lenses located in the Galactic halo would have a velocity projected to the SMC of <(upsilon)over cap> similar to 1500 kms(-1), while an SMC lens would typically have <(upsilon)over cap> similar to 60 kms(-1). The event light curve allows us to obtain a unique fit to the parameters of the binary lens and to estimate the proper motion of the lensing system. We have performed a joint fit to the MACHO/GMAN data presented here, including recent EROS data of this event from Afonso and collaborators. These joint data are sufficient to constrain the time t(*) for the lens to move an angle equal to the source angular radius: t(*) = 0.116 +/- 0.010 days. We estimate a radius for the lensed source of R-* = 1.1 +/- 0.1 R. from its unblended color and magnitude. This yields a projected velocity of <(upsilon)over cap> = 76 +/- 10 kms(-1). Only 0.12% of halo lenses would be expected to have a <(upsilon)over cap> value at least as small as this, while 38% of SMC lenses would be expected to have <(upsilon)over cap> as large as this. This implies that the lensing system is more likely to reside in the SMC than in the Galactic halo. Similar observations of future Magellanic Cloud microlensing events will help to determine the contribution of MACHOS to the Galaxy's dark halo. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, Canberra, ACT 0200, Australia. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, 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. European So Observ, D-85748 Garching, Germany. Natl Res Council Canada, Victoria, BC V8X 4M6, Canada. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. 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 36 TC 40 Z9 40 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 JUN 10 PY 1999 VL 518 IS 1 BP 44 EP 49 DI 10.1086/307265 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211JZ UT WOS:000081158600004 ER PT J AU Haiman, Z Spaans, M AF Haiman, Z Spaans, M TI Models for dusty Ly alpha emitters at high redshift SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : ISM; galaxies : stellar content; stars : formation; ultraviolet : galaxies ID RESONANCE-LINE RADIATION; STAR-FORMING GALAXIES; GUNN-PETERSON TROUGH; PRIMEVAL GALAXIES; COSMOLOGICAL CONSTANT; INTERGALACTIC MEDIUM; DISK GALAXIES; REIONIZATION; EMISSION; UNIVERSE AB Models are presented for the Ly alpha emission of dusty high-redshift galaxies by combining the Press-Schechter formalism with a treatment of the inhomogeneous dust distribution inside galaxies. It is found that the amount of Ly alpha radiation escaping from the galaxies strongly depends on the time over which the dust is produced through stellar activity and on the ambient inhomogeneity of the H II regions that surround the ionizing OB stars. Good agreement is found with recent observations, as well as with previous nondetections. Although a detailed determination of the individual model parameters is precluded by uncertainties, we find that (1) the dust content in primordial galaxies builds up in no more than similar to 5 x 10(8) yr, (2) the galactic H II regions are inhomogeneous with a cloud-covering factor of order unity, and (3) the overall star formation efficiency is at least similar to 5%. It is predicted that future observations can detect these Ly alpha galaxies up to redshifts of similar to 8. If the universe is reionized at z(r) less than or similar to 8, the corresponding decline in the number of Ly alpha emitters at z greater than or similar to z(r) could prove to be a useful probe of the reionization epoch. C1 NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Haiman, Z (reprint author), NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. NR 59 TC 108 Z9 108 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 JUN 10 PY 1999 VL 518 IS 1 BP 138 EP 144 DI 10.1086/307276 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211JZ UT WOS:000081158600012 ER PT J AU Fenimore, EE AF Fenimore, EE TI The average temporal and spectral evolution of gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma-rays : bursts ID MODELS AB We have averaged bright BATSE bursts to uncover the average overall temporal and spectral evolution of gamma-ray bursts (GRBs). We align the temporal structure of each burst by setting its duration to a standard duration, which we call T-[DUR]. The observed average "aligned T-[Dur]" profile for 32 bright bursts with intermediate durations (16-40 s) has a sharp rise (within the first 20% of T-[Dur]) and then a linear decay. Exponentials and power laws do not fit this decay. In particular, the power law seen in the X-ray afterglow (proportional to T-1.4) is not observed during the bursts, implying that the X-ray afterglow is not just an extension of the average temporal evolution seen during the gamma-ray phase. The average burst spectrum has a low-energy slope of -1.03, a high-energy slope of -3.31, and a peak in the nu F-nu distribution at 390 keV. We determine the average spectral evolution. Remarkably, it is also a linear function, with the peak of the nu F-nu distribution given by similar to 680 - 600(T/T-[Dur]) keV. Since both the temporal profile and the peak energy are linear functions, on average, the peak energy is linearly proportional to the intensity. This behavior is inconsistent with the external shock model. The observed temporal and spectral evolution is also inconsistent with that expected from variations in just a Lorentz factor. Previously, trends have been reported for GRB evolution, but our results are quantitative relationships that models should attempt to explain. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fenimore, EE (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D436, Los Alamos, NM 87545 USA. NR 14 TC 24 Z9 24 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 JUN 10 PY 1999 VL 518 IS 1 BP 375 EP 379 DI 10.1086/307245 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 211JZ UT WOS:000081158600031 ER PT J AU Fisher, IA Bell, AT AF Fisher, IA Bell, AT TI A mechanistic study of methanol decomposition over Cu/SiO2, ZrO2/SiO2, and Cu/ZrO2/SiO2 SO JOURNAL OF CATALYSIS LA English DT Article ID SUPPORTED COPPER-CATALYSTS; AEROGEL CATALYSTS; CARBON-MONOXIDE; INFRARED-SPECTROSCOPY; ZIRCONIUM DIOXIDE; METHYL FORMATE; CU-ZRO2 CATALYSTS; SYNTHESIS GAS; FORMIC-ACID; ZINC-OXIDE AB The interaction of methanol with Cu/SiO2, ZrO2/SiO2, and Cu/ZrO2/SiO2 has been investigated by in situ infrared spectroscopy and temperature programmed desorption and reaction with the aim of understanding the nature of the species and the mechanism involved in methanol decomposition. In the case of Cu/SiO2, methanol exposure results in the formation of methoxide species on Cu and SiO2 at 323 K. In the absence of methanol in the gas phase, methoxide species on Cu are dehydrogenated to give formaldehyde starting at similar to 340 K and are oxidized to formate species at similar to 373 K, which then decomposes to CO2 and H-2 at similar to 390 K. When methanol is present in the gas phase, methyl formate, CO2 and H-2, resulting from the decomposition of methyl formate, are formed in addition to the above reactions. When ZrO2/SiO2 or Cu/ZrO2/SiO2 is exposed to methanol, the majority of the surface species observed are associated with zirconia. Methanol adsorption on either ZrO2/SiO2 or Cu/ZrO2/SiO2 leads to methoxide formation on zirconia and SiO2 at 323 K. In the presence of Cu, methoxide species on zirconia are dehydrogenated to give formaldehyde starting at similar to 325 K, which is oxidized to formate species on zirconia at similar to 373 K, which decompose to CO, CO2, and H-2 at similar to 400 K. Methyl formate and dimethyl ether are also observed to form above 460 K. In the absence of Cu, methoxide species on zirconia decompose only very slowly at 523 K. Metallic Cu is proposed to provide sites on which hydrogen atoms formed during the dehydrogenation of species located on zirconia can recombine efficiently and desorb as H-2. Thus, methanol decomposition over Cu/ZrO2/SiO2 is envisioned to occur primarily on ZrO2, with the primary function of Cu being the removal of hydrogen. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Fisher, IA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. NR 59 TC 132 Z9 134 U1 10 U2 94 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 JUN 10 PY 1999 VL 184 IS 2 BP 357 EP 376 DI 10.1006/jcat.1999.2420 PG 20 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 206YU UT WOS:000080908900006 ER PT J AU Rider, WJ Knoll, DA Olson, GL AF Rider, WJ Knoll, DA Olson, GL TI A multigrid Newton-Krylov method for multimaterial equilibrium radiation diffusion SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE equilibrium radiation diffusion; multigrid; Newton-Krylov ID EQUATIONS; SYSTEMS; FLOWS AB We focus on a fully implicit, nonlinearly converged, solution of multimaterial equilibrium radiation diffusion problems. The nonlinear method of solution is a Newton-Krylov (generalized minimum residual, GMRES) method preconditioned by a multigrid method. The multigrid iteration matrix results from a Picard-type linearization of the governing equations. The governing equation is highly nonlinear with the principal forms of nonlinearity found in the fourth-order dependence of the radiation energy on temperature, the temperature dependence of the opacity, and flux limiting. The efficiency of both the linear and nonlinear iterative techniques is investigated. With the realistic time step control the solution of the linear system does not scale linearly with multigrid as might be expected from theory. In contrast, we find that the use of multigrid to precondition a Newton-Krylov (GMRES) method provides a robust, scalable solution for the nonlinear system. Also only through converging the nonlinearities within a time step does the solution method achieve its design accuracy. C1 Univ Calif Los Alamos Natl Lab, Hydrodynam Methods Grp, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Transport Methods Grp, Los Alamos, NM 87545 USA. RP Rider, WJ (reprint author), Univ Calif Los Alamos Natl Lab, Hydrodynam Methods Grp, Appl Theoret & Computat Phys Div, POB 1663,MS D413, Los Alamos, NM 87545 USA. NR 22 TC 28 Z9 32 U1 0 U2 2 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 JUN 10 PY 1999 VL 152 IS 1 BP 164 EP 191 DI 10.1006/jcph.1999.6240 PG 28 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 206FU UT WOS:000080867300007 ER PT J AU Azmy, YY AF Azmy, YY TI Iterative convergence acceleration of neutral particle transport methods via adjacent-cell preconditioners SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE preconditioning; adjacent-cell preconditioner; neutral particle transport; spectral analysis ID DIFFUSION-SYNTHETIC ACCELERATION; DISCRETE-ORDINATES EQUATIONS AB We propose preconditioning as a viable acceleration scheme for the inner iterations of transport calculations in slab geometry. In particular we develop Adjacent-Cell Preconditioners (AP) that have the same coupling stencil as cell-centered diffusion schemes. For lowest order methods, e.g., Diamond Difference, Step, and 0-order Nodal Integral Method (0NIM), cast in a Weighted Diamond Difference (WDD) form, we derive AP for thick (KAP) and thin (NAP) cells that for model problems are unconditionally stable and efficient. For the First-Order Nodal Integral Method (1NIM) we derive a NAP that possesses similarly excellent spectral properties for model problems, [Note that the order of NIM refers to the truncated order of the local expansion of the cell and edge fluxes in Legendre series.] The two most attractive features of our new technique are: (1) its cell-centered coupling stencil, which makes it more adequate for extension to multidimensional, higher order situations than the standard edge-centered or point-centered Diffusion Synthetic Acceleration (DSA) methods; and (2) its decreasing spectral radius with increasing cell thickness to the extent that immediate pointwise convergence, i.e., in one iteration, can be achieved for problems with sufficiently thick cells. We implemented these methods, augmented with appropriate boundary conditions and mixing formulas for material heterogeneities, in the test code AP1D that we use to successfully verify the analytical spectral properties for homogeneous problems. Furthermore, we conduct numerical tests to demonstrate the robustness of the KAP and NAP in the presence of sharp mesh or material discontinuities. We show that the AP for WDD is highly resilient to such discontinuities, but for 1NIM a few cases occur in which the scheme does not converge; however, when it converges, AP greatly reduces the number of iterations required to achieve convergence. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Oak Ridge Natl Lab, POB 2008,MS 6363, Oak Ridge, TN 37831 USA. EM yya@ornl.gov NR 18 TC 6 Z9 6 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN 10 PY 1999 VL 152 IS 1 BP 359 EP 384 DI 10.1006/jcph.1999.6251 PG 26 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 206FU UT WOS:000080867300015 ER PT J AU Lowman, JP Jarvis, GT AF Lowman, JP Jarvis, GT TI Effects of mantle heat source distribution on supercontinent stability SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID 3-DIMENSIONAL SPHERICAL-MODELS; EARTHS MANTLE; FLOOD BASALTS; CONTINENTAL COLLISIONS; LAYERED CONVECTION; GENERATION; BREAKUP; PLATES; GONDWANALAND; CRATONS AB A two-dimensional Cartesian geometry numerical model is used to study the influence of internal heating on the ability of mantle convection to rift and disperse an assembled supercontinent. Our wide aspect ratio models incorporate migrating plate boundaries and finite thickness rigid mobile oceanic and continental plates (similar to 12,000 km across). We examine models characterized by both whole mantle and upper mantle convection parameters. Specifying different degrees of internal heating in the mantle, we compare the patterns of convection that develop below stationary continental plates that form as a result of the aggregation of smaller mobile continents. Following continental collisions, we find that a reorganization of mantle flow may result in the development of deviatoric Stresses at the base of the continental lithosphere, which are capable of initiating continental breakup. Our results suggest that continental basal stresses are largely controlled by the wavelength of the subcontinental convection pattern and that the inclusion of internal heating in the mantle generally increases this wavelength. For models with 80% internal heating (in which active upwellings are intrinsically absent), basal stresses arise primarily from subduction at the continental margins and result in a geologically reasonable duration for our model supercontinent assemblages (similar to 200 Myr). For models with 40% or less internal heating, continental breakup is controlled by mantle upwellings and our supercontinents remain intact much longer (similar to 600-700 Myr). C1 York Univ, Ctr Res Earth & Space Sci, Toronto, ON M3J 1P3, Canada. York Univ, Dept Earth & Atmospher Sci, Toronto, ON M3J 2R7, Canada. RP Los Alamos Natl Lab, Inst Geophys & Planetary Phys, MS C305, Los Alamos, NM 87545 USA. EM lowman@lanl.gov; jarvis@mantle.eats.yorku.ca NR 49 TC 37 Z9 37 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 JUN 10 PY 1999 VL 104 IS B6 BP 12733 EP 12746 DI 10.1029/1999JB900108 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 205GM UT WOS:000080813000001 ER PT J AU Peters, DW Bourret, ED Power, MP Arnold, J AF Peters, DW Bourret, ED Power, MP Arnold, J TI Reactions of trialkylgalliums with substituted hydrazines leading to the formation of rings and cages: X-ray structures of ((Pr2GaNHNMe2)-Pr-i)(2) and ((MeGaNHNBu)-Bu-t)(4) SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE trialkylgallium; hydrazine; cage ID NANOCRYSTALLINE GALLIUM NITRIDE; SINGLE-SOURCE PRECURSORS; CRYSTAL-STRUCTURES; HETEROEPITAXIAL GAN; ARSENIC COMPOUNDS; COMPLEXES; AMINE; TRIMETHYLGALLIUM; DERIVATIVES; PHOSPHORUS AB The reaction of trialkylgalliums with substituted hydrazines forms simple Lewis acid-base adducts at room temperature. Subsequent thermolysis of these adducts leads to step by step alkane loss forming first dimeric rings, then tetrameric cages. Thus the dimeric compounds [Me2GaNHNMe2](2), [Et2GaNHNMe2](2), [Me2GaNHNPh2](2), [Et2GaNHNPh2](2), [(Pr2GaNHNMe2)-Pr-i](2), and [(Me2GaNHNHBu)-Bu-t](2), have been synthesized. In addition, [(Pr2GaNHNMe2)-Pr-i](2) has been characterized crystallographically. Although exclusively in the anti conformation in the solid state, the dimers are fluxional in solution at room temperature. The fluxionalityl is examined in detail by NMR spectroscopy. The tetrameric [(MeGaNHNBu)-Bu-t](4) has been isolated and crystallographically characterized. It is shown to have a cage structure consisting of two hexagonal and four pentagonal rings. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mat 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 43 TC 37 Z9 37 U1 2 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD JUN 10 PY 1999 VL 582 IS 1 BP 108 EP 115 DI 10.1016/S0022-328X(98)01193-0 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 208TL UT WOS:000081007800017 ER PT J AU LaViolette, RA Watwood, ME Ginn, TR Stoner, DL AF LaViolette, RA Watwood, ME Ginn, TR Stoner, DL TI Spatial disorder and degradation kinetics in intrinsic biodegradation schemes SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID BACTERIA AB The restoration of contaminated soils by intrinsic biodegradation employs microorganisms in the subsurface that degrade the contaminant substrate infiltrating the subsurface matrix. The outcome of intrinsic biodegradation has been difficult to predict. We examine a source of the difficulty with a computational model of diffusive-reactive transport that introduces spatial disorder in the arrangement of the degrading microorganisms. Spatial disorder alone, even on the small scales that characterize the distance between aggregates of microorganisms, is enough to induce a wide range of times to complete the degradation to an arbitrary limit. The mean time for the concentration to achieve the limit becomes twice that for the case of spatial order. Bounds on the range of the effective degradation kinetics can be obtained by computing the distribution of times to complete degradation. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Idaho State Univ, Dept Biol Sci, Pocatello, ID 83209 USA. Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA. RP LaViolette, RA (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 23 TC 3 Z9 3 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 10 PY 1999 VL 103 IS 23 BP 4480 EP 4484 DI 10.1021/jp984652+ PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 206YH UT WOS:000080907800008 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, G Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, C Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, C Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PC Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, G Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, C Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, C Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PC Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M CA L3 Collaboration TI Search for scalar leptons in e(+)e(-) collisions at root s=183 GeV SO PHYSICS LETTERS B LA English DT Article ID MEDIATED SUPERSYMMETRY-BREAKING; ELECTRON-POSITRON COLLISIONS; ANGLE BHABHA SCATTERING; STATE QED CORRECTIONS; W-PAIR PRODUCTION; MONTE-CARLO; STANDARD MODEL; L3 EXPERIMENT; LOCAL SUPERSYMMETRY; E+E COLLISIONS AB We report the result of a search for scaler leptons in e(+)e(-)collisions at 183 GeV centre-of-mass energy at LEP. No evidence for such particles is found in a data sample of 55.2 pb(-1). improved upper limits are set on the production cross-sections for stable as well as unstable scalar leptons, New exclusion contours in the parameter space of the Minimal Supersymmetric Standard Model are derived, as well as new lower limits on scalar lepton masses. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF H, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. Lab Annecy Le Vieux Phys Particules, CNRS, IN2P3, F-74941 Annecy Le Vieux, France. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. FBLJA Project, World Lab, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Chinese Univ Sci & Technol, USTC, Hefei 230029, Anhui, Peoples R China. Res Inst High Energy Phys, SEFT, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, Inst Phys Nucl Lyon, CNRS, IN2P3, F-69622 Villeurbanne, France. CIEMAT, E-28040 Madrid, Spain. Inst Theoret & Expt Phys, Moscow 117259, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Catholic Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Russian Acad Sci, Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago De Compostela, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, University, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF H, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. Natl Tsing Hua Univ, Dept Phys, Hsinchu, Taiwan. RP Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy. RI Duran, Ignacio/H-7254-2015; Sanchez, Eusebio/H-5228-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015; Achard, Pablo/C-2983-2009 OI Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Di Lodovico, Francesca/0000-0003-3952-2175; Castellini, Guido/0000-0002-0177-0643; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306; Achard, Pablo/0000-0002-4865-3196 NR 55 TC 4 Z9 4 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUN 10 PY 1999 VL 456 IS 2-4 BP 283 EP 296 DI 10.1016/S0370-2693(99)00447-5 PG 14 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 209AD UT WOS:000081024100026 ER PT J AU Mullins, DR Radulovic, PV Overbury, SH AF Mullins, DR Radulovic, PV Overbury, SH TI Ordered cerium oxide thin films grown on Ru(0001) and Ni(111) SO SURFACE SCIENCE LA English DT Article DE cerium oxide; low energy ion scattering (LEIS); low index single crystal surfaces; nickel; ruthenium; soft X-ray photoelectron spectroscopy; synchrotron radiation photoelectron spectroscopy ID X-RAY PHOTOELECTRON; ION-SCATTERING; SINGLE-CRYSTAL; SURFACES; ADSORPTION; OXIDATION; SPECTROSCOPY; OVERLAYERS; REDUCTION; PT(111) AB Cerium oxide thin films between 1-10 ML thick have been grown in situ on the Ru(0001) and Ni(111) surfaces. The films were highly ordered with an orientation determined by the orientation of the substrate on which they were grown, as shown by ion scattering spectroscopy and low-energy electron diffraction. The principal azimuths of the oxide films were aligned parallel to the principal azimuths of the substrates. The lattice constant of the films was nominally the same as for CeO2 with a fluorite structure. Optimal films were grown by dosing metallic Ce at a rate of ca 3 x 10(14) min(-1) cm(-2) in an oxygen background while the substrate was at 700 K. Fully oxidized films could be grown by using an oxygen pressure near 10(-7) Torr, whereas substoichiometric films could be grown by decreasing the oxygen pressure. The fully oxidized films were predominantly terminated by an oxygen layer, whereas the substoichiometric films had a significant amount of cerium in the top layer. The structure of the reduced oxide films was most consistent with a CeO2(111) surface that contained numerous oxygen vacancies. The films grown on Ru(0001) were fully stable in terms of structure and composition at temperatures up to 1000 K. The films grown on Ni(111) lost oxygen upon annealing to 1000 K. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Mullins, DR (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 32 TC 195 Z9 197 U1 3 U2 61 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 1999 VL 429 IS 1-3 BP 186 EP 198 DI 10.1016/S0039-6028(99)00369-6 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 209FH UT WOS:000081037200029 ER PT J AU Rodriguez, JA Dvorak, J Capitano, AT Gabelnick, AM Gland, JL AF Rodriguez, JA Dvorak, J Capitano, AT Gabelnick, AM Gland, JL TI Adsorption of thiophene on surfaces of clean and Ni-promoted molybdenum sulfide SO SURFACE SCIENCE LA English DT Letter DE aromatics; chemisorption; molybdenum sulfide; nickel; photoelectron spectroscopy; sulfur; thiophene ID TRANSITION-METAL SULFIDES; HYDROGEN-SULFIDE; MO CATALYSTS; HYDRODESULFURIZATION; DECOMPOSITION; HDS; DESULFURIZATION; MECHANISM; MO(110); SULFUR AB Synchrotron-based high-resolution photoemission has been used to study the interaction of thiophene with pure and Ni promoted MoSx films. The films exhibit Mo 3d and valence spectra that are very similar to those of MoS2. On the MoSx systems, the chemistry of thiophene closely resembles that seen on MoS2(0002). The molecules are weakly chemisorbed, and most of them desorb at temperatures around 200 K. A small fraction of the adsorbed thiophene is bonded to Mo sites that have S vacancies and desorbs between 250 and 300 K. The addition of Ni enhances the chemical activity of MoSx. On the NiMoSx systems, the adsorption energy of thiophene is at least 5-10 kcal mol(-1) larger than on pure MoSx. No dissociation of the molecules is observed on the NiMoSx surfaces. The Ni<->S interactions reduce the reactivity of nickel, and the presence of this metal alone is not enough to promote or facilitate the cleavage of C-S bonds in hydrodesulfurization (HDS) reactions. Hydrogen seems to play an important role in this aspect. The behavior of NiMoSx catalysts in HDS processes is discussed in the light of these results. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 35 TC 38 Z9 38 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 1999 VL 429 IS 1-3 BP L462 EP L468 DI 10.1016/S0039-6028(99)00348-9 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 209FH UT WOS:000081037200002 ER PT J AU Yang, CS Bley, RA Kauzlarich, SM Lee, HWH Delgado, GR AF Yang, CS Bley, RA Kauzlarich, SM Lee, HWH Delgado, GR TI Synthesis of alkyl-terminated silicon nanoclusters by a solution route SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID INFRARED-ABSORPTION PEAKS; OXIDIZED POROUS SILICON; COLLOIDAL SILICON; QUANTUM CONFINEMENT; NANOCRYSTALS; NANOPARTICLES; SPECTROSCOPY; LUMINESCENCE; IDENTIFICATION; CRYSTALLITES AB We describe the synthesis and characterization of alkyl-capped nanocrystalline Si ((R) over cap-n-Si) prepared by the reaction of SiCl(4) with Mg(2)Si in ethylene glycol dimethyl ether (glyme) and surface-terminated with various alkyl groups, (R) over cap-n-Si (R = methyl, ethyl, n-butyl, and n-octyl). This reaction produces crystalline nanoparticles with surfaces that can be chemically modified. The resultant crystalline nanoparticles can be suspended in organic solvents or isolated as a powder. The nanoclusters were characterized by transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction (SAED), and Fourier transform infrared (FTIR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, UV-vis absorption, and photoluminescence spectroscopy. The average cluster size depends on the reflux time of Mg2Si with SiCl(4), which provided nanoclusters with an average size bf 2-5 MI. HRTEM confirms the presence of crystalline nanoclusters, and SAED is consistent with diamond-structured silicon. FTIR spectra are consistent with alkyl surface termination and show very little or no evidence for oxygen on the surface of the nanoclusters, depending on the surface alkyl group. The alkyl termination can be removed by reaction in air at 450 degrees C, and a Si-O stretch is observed in the FTIR spectra: EPR spectroscopy is consistent with crystalline Si nanoclusters and shows no signal at 4 K. The optical absorption spectra show an absorption edge between 260 and 240 nm, depending on the surface alkyl group, while a strong UV-blue photoluminescence between 315 and 520 nm is observed. C1 Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kauzlarich, SM (reprint author), Univ Calif Davis, Dept Chem, 1 Shields Ave, Davis, CA 95616 USA. NR 41 TC 218 Z9 222 U1 9 U2 104 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 JUN 9 PY 1999 VL 121 IS 22 BP 5191 EP 5195 DI 10.1021/ja9828509 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA 206AP UT WOS:000080854100012 ER PT J AU Pond, AE Roach, MP Sono, M Rux, AH Franzen, S Hu, R Thomas, MR Wilks, A Dou, Y Ikeda-Saito, M de Montelano, PRO Woodruff, WH Boxer, SG Dawson, JH AF Pond, AE Roach, MP Sono, M Rux, AH Franzen, S Hu, R Thomas, MR Wilks, A Dou, Y Ikeda-Saito, M de Montelano, PRO Woodruff, WH Boxer, SG Dawson, JH TI Assignment of the heme axial ligand(s) for the ferric myoglobin (H93G) and heme oxygenase (H25A) cavity mutants as oxygen donors using magnetic circular dichroism SO BIOCHEMISTRY LA English DT Article ID SITE-DIRECTED MUTAGENESIS; RESONANCE RAMAN-SPECTROSCOPY; CYTOCHROME-C PEROXIDASE; SPERM WHALE MYOGLOBIN; M-HYDE-PARK; EXOGENOUS LIGANDS; PROXIMAL LIGAND; HORSERADISH-PEROXIDASE; CATALYTIC MECHANISM; THIOLATE LIGATION AB UV-visible absorption and magnetic circular dichroism (MCD) data are reported for the cavity mutants of sperm. whale H93G myoglobin and human H25A heme oxygenase in their ferric states at 4 OC. Detailed spectral analyses of H93G myoglobin reveal that its heme coordination structure has a single water ligand at pH 5.0, a single hydroxide ligand at pH 10.0, and a mixture of species at pH 7.0 including five-coordinate hydroxide-bound, and six-coordinate structures. The five-coordinate aquo structure at pH 5 is supported by spectral similarity to acidic horseradish peroxidase (pH 3.1), whose MCD data are reported herein for the first time, and acidic myoglobin (pH 3.4), whose structures have been previously assigned by resonance Raman spectroscopy. The five-coordinate hydroxide structure at pH 10.0 is supported by MCD and resonance Raman data obtained here and by comparison with those of other known five-coordinate oxygen donor complexes. In particular, the MCD spectrum of alkaline ferric H93G myoglobin is strikingly similar to that of ferric tyrosinate-ligated human H93Y myoglobin, whose MCD data are reported herein for the first time, and that of the methoxide adduct of ferric protoporphyrin IX dimethyl eater ((FePPIXDME)-P-III). Analysis of the spectral data for ferric H25A heme oxygenase at neutral pH in the context of the spectra of other five-coordinate ferric heme complexes with proximal oxygen donor ligands, in particular the p-nitrophenolate and acetate adducts of (FePPIXDME)-P-III, is most consistent with ligation by a carboxylate group of a nearby glutamyl (or aspartic) acid residue. C1 Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. Inst Mol Sci, Dept Struct Mol Sci, Okazaki, Aichi 444, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Univ Calif San Francisco, Sch Pharm, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. Case Western Reserve Univ, Sch Med, Dept Physiol & Biophys, Cleveland, OH 44106 USA. Univ S Carolina, Sch Med, Columbia, SC 29208 USA. RP Dawson, JH (reprint author), Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. RI Ikeda-Saito, Masao/A-5992-2008; OI Dawson, John/0000-0002-4902-4295 FU NIGMS NIH HHS [GM 26730, GM 27738, GM 51588] NR 47 TC 51 Z9 51 U1 2 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 8 PY 1999 VL 38 IS 23 BP 7601 EP 7608 DI 10.1021/bi9825448 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 206ZV UT WOS:000080911600022 PM 10360958 ER PT J AU Thompson, AP Heffelfinger, GS AF Thompson, AP Heffelfinger, GS TI Direct molecular simulation of gradient-driven diffusion of large molecules using constant pressure SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NANOPOROUS CARBON MEMBRANES; MONTE-CARLO SIMULATION; LENNARD-JONES FLUIDS; DYNAMICS SIMULATION; COMPUTER-SIMULATION; GAS PERMEATION; DCV-GCMD; COEFFICIENTS; FLOW; TRANSPORT AB Dual control volume grand canonical molecular dynamics (DCV-GCMD) is a boundary-driven nonequilibrium molecular-dynamics technique for simulating gradient-driven diffusion in multicomponent systems. Two control volumes are established at opposite ends of the simulation box. Constant temperature and chemical potential of diffusing species are imposed in the control volumes (i.e., constant-mu(1)... mu(n-1)mu(n) VT). This results in stable chemical potential gradients and steady-state diffusion fluxes in the region between the control volumes. We present results and detailed analysis for a new constant-pressure variant of the DCV-GCMD method in which one of the diffusing species for which a steady-state diffusion flux exists does not have to be inserted or deleted. Constant temperature, pressure, and chemical potential of all diffusing species except one are imposed in the control volumes (i.e., constant-mu(1) ... mu(n-1)N(n)PT). The constant-pressure method can be applied to situations in which insertion and deletion of large molecules would be prohibitively difficult. As an example, we used the method to simulate diffusion in a binary mixture of spherical particles with a 2:1 size ratio. Steady-state diffusion fluxes of both diffusing species were established. The constant-pressure diffusion coefficients agreed closely with the results of the standard constant-volume calculations. In addition, we show how the concentration, chemical potential, and flux profiles can be used to calculate local binary and Maxwell-Stefan diffusion coefficients. In the case of the 2:1 size ratio mixture, we found that the binary diffusion coefficients were asymmetric and composition dependent, whereas the Maxwell-Stefan diffusion coefficients changed very little with composition and were symmetric. This last result verified that the Gibbs-Duhem relation was satisfied locally, thus validating the assumption of local equilibrium. (C) 1999 American Institute of Physics. [S0021-9606(99)50418-2]. C1 Sandia Natl Labs, Mat Simulat Sci Dept, Albuquerque, NM 87185 USA. RP Thompson, AP (reprint author), Sandia Natl Labs, Mat Simulat Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 38 TC 36 Z9 36 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 JUN 8 PY 1999 VL 110 IS 22 BP 10693 EP 10705 DI 10.1063/1.478996 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 199FF UT WOS:000080469200008 ER PT J AU Leung, K Whaley, KB AF Leung, K Whaley, KB TI Surface relaxation in CdSe nanocrystals SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENERGY-ELECTRON-DIFFRACTION; EXCITON FINE-STRUCTURE; QUANTUM DOTS; SEMICONDUCTOR CLUSTERS; EXCHANGE; STATE; LUMINESCENCE; NANOCLUSTERS; ABSORPTION; CRYSTALLITES AB Total energy minimization is applied to semiempirical tight-binding CdSe nanocrystal models with diameter up to 31 Angstrom. The crystallites have wurtzite lattice structure and ligand-terminated surfaces. It is found that the qualitative features of the surface relaxation in nanocrystals and at bulk surfaces are similar. When surface relaxation is incorporated, the onsets of absorption are determined by interior-to-interior transitions with little contribution from surface-localized states. The fine structure and exchange splittings derived from these clusters are in good agreement with experimental measurements. The effects of ligand parametrization, surface atom composition, and the contribution of surface states to the exciton fine structure are analyzed. (C) 1999 American Institute of Physics. [S0021-9606(99)70320-X]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Leung, K (reprint author), Sandia Natl Labs, MS 1421, Albuquerque, NM 87185 USA. NR 49 TC 78 Z9 78 U1 2 U2 19 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 JUN 8 PY 1999 VL 110 IS 22 BP 11012 EP 11022 DI 10.1063/1.479037 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 199FF UT WOS:000080469200044 ER PT J AU Gibiansky, LV Milton, GW Berryman, JG AF Gibiansky, LV Milton, GW Berryman, JG TI On the effective viscoelastic moduli of two-phase media. III. Rigorous bounds on the complex shear modulus in two dimensions SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE two-component composite material; viscoelastic constants; shear modulus; translation bounds; Hashin-Shtrikman bounds; homogenization ID 2-PHASE MEDIA; COMPOSITES; BULK; ELASTICITY; BEHAVIOR AB The translation and the Hashin-Shtrikman methods are used to provide bounds on the effective complex shear modulus of a two-phase two-dimensional viscoelastic composite. They are both given by inequalities that depend on six parameters. The best bounds are obtained by optimizing these parameters over the admissible set, which is larger for the translation method than for the Hashin-Shtrikman method. Consequently, the translation method generally leads to tighter bounds than would be obtained via the standard Hashin-Shtrikman approach. Equivalence classes of two-dimensional viscoelastic composites (directly analogous to similar classes for the pure elastic problem) are found. Combination of the simplified versions of the translation or the Hashin-Shtrikman-type bounds and this equivalency results in simple algorithms for computing tight bounds for any choice of phase moduli and volume fractions. The bounds constrain the effective shear modulus to lie inside a region of the complex plane bounded by arcs of circles. The four points which correspond to the Hashin-Shtrikman-Walpole bounds on the shear modulus of an elastic composite always lie inside or on the boundary of the bounding region. In many cases the bounding region tends to hug the corresponding parallelogram in the complex compliance plane having these four points as vertices. C1 Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. Univ Utah, Dept Math, Salt Lake City, UT 84112 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Gibiansky, LV (reprint author), 49 Flints Grove Dr, N Potomac, MD 20878 USA. RI Berryman, James/A-9712-2008 NR 28 TC 15 Z9 15 U1 1 U2 3 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD JUN 8 PY 1999 VL 455 IS 1986 BP 2117 EP 2149 PG 33 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 211JA UT WOS:000081156100008 ER PT J AU Wiederrecht, GP Wasielewski, MR AF Wiederrecht, GP Wasielewski, MR TI Photorefractive Bragg gratings in nematic liquid crystals aligned by a magnetic field SO APPLIED PHYSICS LETTERS LA English DT Article ID POLYMER AB Photorefractive Bragg gratings are observed in low-molar-mass nematic liquid crystals doped with electron donor and acceptor molecules. This is accomplished by alignment of the nematic liquid crystals in a 0.3 T magnetic field, which produces thicker homeotropic aligned samples than traditional surfactant techniques. Grating fringe spacings as low as 3.7 mu m are achieved with 176-mu m-thick samples, producing grating Q values of 33. Up to this point, low molar mass nematic liquid crystals have exhibited photorefractive gratings with Q less than or equal to 1. Asymmetric two-beam coupling and photoconductivity experiments are performed to verify the photorefractive origin of the gratings. (C) 1999 American Institute of Physics. [S0003-6951(99)05023-8]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM wasielew@chem.nwu.edu NR 30 TC 9 Z9 9 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 JUN 7 PY 1999 VL 74 IS 23 BP 3459 EP 3461 DI 10.1063/1.124127 PG 3 WC Physics, Applied SC Physics GA 200BL UT WOS:000080519000011 ER PT J AU Jiang, W Thevuthasan, S Weber, WJ Namavar, F AF Jiang, W Thevuthasan, S Weber, WJ Namavar, F TI Ion-channeling study of the SiC/Si/SiO2/Si interface SO APPLIED PHYSICS LETTERS LA English DT Article ID STRAINED-LAYER SUPERLATTICE; SUPER-LATTICES AB Ion channeling has been used in a detailed study of 3C-SiC films grown by chemical vapor deposition on a Si/SiO2/Si substrate. For a 160-nm-thick [100]-oriented SiC film, the results show a minimum yield (chi(min)) of similar to 28% at the SiC-Si interface, while a SiC film with a thickness of similar to 2.4 mu m, grown under identical conditions, was almost defect free (chi(min) = 5.3%) in the surface region. Angular scans around the [110] axis revealed the existence of a superlattice structure at the SiC-Si interface. The strain-induced angular shift was determined to be 0.16 degrees +/- 0.05 degrees, indicating a kink between the SiC and Si layers along the inclined [110] axis. A modified model is suggested to interpret the experimental observations. (C) 1999 American Institute of Physics. [S0003-6951(99)02923-X]. C1 Pacific NW Lab, Richland, WA 99352 USA. Spire Corp, Bedford, MA 01730 USA. RP Jiang, W (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; OI Weber, William/0000-0002-9017-7365; Jiang, Weilin/0000-0001-8302-8313 NR 15 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 7 PY 1999 VL 74 IS 23 BP 3501 EP 3503 DI 10.1063/1.124143 PG 3 WC Physics, Applied SC Physics GA 200BL UT WOS:000080519000025 ER PT J AU Ahrenkiel, SP Johnston, SW Ahrenkiel, RK Arent, DJ Hanna, MC Wanlass, MW AF Ahrenkiel, SP Johnston, SW Ahrenkiel, RK Arent, DJ Hanna, MC Wanlass, MW TI Atomic ordering and temperature-dependent transient photoconductivity in Ga0.47In0.53As SO APPLIED PHYSICS LETTERS LA English DT Article ID GAINP; IN0.53GA0.47AS; RECOMBINATION; GA0.5IN0.5P; ALLOYS; FIELDS AB Influences of CuPtB atomic ordering on transient photoconductivity in epitaxial Ga0.47In0.53As films grown by metal-organic chemical vapor deposition are examined. Low-injection lifetimes of several ms are measured in double-variant ordered samples at 77 K; these lifetimes decrease rapidly with temperatures above 180 K, giving a thermal activation energy for recombination of 0.19 eV. Single-variant ordered samples exhibit typical lifetimes of 30-60 mu s, with no noticeable temperature dependence up to 300 K. Charge separation in double-variant samples may be driven by a type-II band alignment between ordered and disordered regions, or by an alternating internal electrical polarization between ordered variants. Recombination in both double- and single-variant samples may be influenced by inhibited transport across antiphase boundaries. (C) 1999 American Institute of Physics. [S0003-6951(99)05223-7]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Ahrenkiel, SP (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 15 TC 7 Z9 7 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 7 PY 1999 VL 74 IS 23 BP 3534 EP 3536 DI 10.1063/1.124152 PG 3 WC Physics, Applied SC Physics GA 200BL UT WOS:000080519000036 ER PT J AU Veenstra, TD AF Veenstra, TD TI Electrospray ionization mass spectrometry in the study of biomolecular non-covalent interactions SO BIOPHYSICAL CHEMISTRY LA English DT Review DE electrospray ionization mass spectrometry; protein metal interactions; protein ligand interactions; protein protein interactions; protein DNA interactions; gas-phase protein conformation ID DNA-BINDING DOMAIN; NONCOVALENT INTERACTIONS; CONFORMATIONAL-CHANGES; GEL-ELECTROPHORESIS; CALBINDIN D-28K; PROTEIN IONS; COMPLEXES; CALCIUM; STOICHIOMETRY; RECEPTOR AB In the past mass spectrometry has been limited to the study of small, stable molecules, however, with the emergence of electrospray ionization mass spectrometry (ESI-MS) large biomolecules as well as non-covalent biomolecular complexes can be studied. ESI-MS has been used to study non-covalent interactions involving proteins with metals, ligands, peptides, oligonucleotides, as well as other proteins. Although complementary to other well-established techniques such as circular dichroism and fluorescence spectroscopy, ESI-MS offers some advantages in speed, sensitivity, and directness particularly in the determination of the stoichiometry of the complex. One major advantage is the ability of ESI-MS to provide multiple signals each arising from a distinct population within the sample. In this review I will discuss some of the different types of non-covalent biomolecular interactions that have been studied using ESI-MS, highlighting examples which show the efficacy of using ESI-MS to probe the structure of biomolecular complexes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Veenstra, TD (reprint author), Pacific NW Lab, Environm & Mol Sci Lab, POB 999,MSIN K8-98, Richland, WA 99352 USA. NR 54 TC 122 Z9 124 U1 1 U2 29 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 J9 BIOPHYS CHEM JI Biophys. Chem. PD JUN 7 PY 1999 VL 79 IS 2 BP 63 EP 79 DI 10.1016/S0301-4622(99)00037-X PG 17 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 205RG UT WOS:000080833900001 PM 17030314 ER PT J AU Goldbach, A Saboungi, ML Iton, L Price, DL AF Goldbach, A Saboungi, ML Iton, L Price, DL TI Stabilization of selenium in zeolites: an anomalous X-ray scattering study SO CHEMICAL COMMUNICATIONS LA English DT Article ID RAMAN-SPECTROSCOPY; CHAINS AB The host-guest interactions in selenium/zeolite encapsulates are investigated with anomalous X-ray scattering (AXS) to rationalize the effects of the cation on the selenium incorporation. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Saboungi, ML (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM mls@anl.gov RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 20 TC 6 Z9 6 U1 0 U2 1 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 JUN 7 PY 1999 IS 11 BP 997 EP 998 DI 10.1039/a900253g PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 202VG UT WOS:000080672400024 ER PT J AU Jacob, J Espenson, JH AF Jacob, J Espenson, JH TI Stereospecific rhenium catalyzed desulfurization of thiiranes SO CHEMICAL COMMUNICATIONS LA English DT Article ID METHYLRHENIUM TRIOXIDE AB Methyltrioxorhenium catalyzes the efficient and stereospecific desulfurization of thiiranes by triphenylphosphine at room temperature, moreso when MTO has been pretreated with hydrogen sulfide, with a Re-V species as the active form of the catalyst. 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 26 TC 21 Z9 21 U1 0 U2 3 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 JUN 7 PY 1999 IS 11 BP 1003 EP 1004 DI 10.1039/a901708i PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 202VG UT WOS:000080672400027 ER PT J AU Markovic, NM Gasteiger, HA Grgur, BN Ross, PN AF Markovic, NM Gasteiger, HA Grgur, BN Ross, PN TI Oxygen reduction reaction on Pt(111): effects of bromide SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE oxygen reduction reaction; bromide; rotating ring-disk technique ID SINGLE-CRYSTAL SURFACES; HYDROGEN EVOLUTION; ACID-SOLUTIONS; ELECTRODES; ADSORPTION AB Using the rotating ring-disk technique (RRDE) the oxygen reduction reaction (orr) was studied on the Pt(111) surface in the presence of Br- anions. We found that the orr at the Pt(111) \ Br-ad interface is always accompanied quantitatively by H2O2 oxidation currents on the ring electrode, implying that in the presence of Br- anions the orr does not proceed entirely through the 4e(-) reduction pathway, as in the Br--free solution. We propose that strongly adsorbed Br- can simultaneously suppress both the adsorption of the O-2 molecule and the formation of pairs of platinum sites needed for the breaking of the O-O bond. Besides elucidating the effects of Br-ad, these studies also shed some light on the role of OHad on the kinetics of the orr on the Pt(111) surface in solution free of Br anions. We have developed a theoretical model and from simulations of I-E curves we propose two modes of action of the OHad state on the kinetics of the orr on the Pt(111) surface: (i) OHad can block the adsorption of O-2 on active platinum sites, i.e. they compete for the same sites, and (ii) OHad can alter the adsorption energy of intermediates which are formed during the orr on the bare Pt sites adjacent to the OHad. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Markovic, NM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. OI Grgur, Branimir/0000-0003-4684-9053 NR 32 TC 258 Z9 261 U1 11 U2 101 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 7 PY 1999 VL 467 IS 1-2 BP 157 EP 163 DI 10.1016/S0022-0728(99)00020-0 PG 7 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 236TE UT WOS:000082614000017 ER PT J AU Marinkovic, NS Marinkovic, JS Adzic, RR AF Marinkovic, NS Marinkovic, JS Adzic, RR TI In situ infrared spectroscopic investigations of sulfate adsorption at the Ag(111) electrode surface SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE FTIR spectroscopy; adsorption; sulfate; silver(111) electrode ID SCANNING-TUNNELING-MICROSCOPY; X-RAY-DIFFRACTION; IN-SITU; SILVER ELECTRODES; UNDERPOTENTIAL DEPOSITION; PLATINUM-ELECTRODES; PT(111) ELECTRODES; ANION ADSORPTION; WATER-MOLECULES; DOUBLE-LAYER AB Cyclic voltammetry and in situ infrared spectroelectrochemistry were employed to study the ionic adsorption on the Ag(111) electrode surface in sulfate-containing solutions of different pH. It has been concluded that the sulfate anion is the predominant species adsorbed at the electrode surface in acidic and neutral medium. The adsorption of sulfate in alkaline solutions is inhibited by the more strongly specifically adsorbed OH- ions. The potential dependence of surface coverage, estimated on the basis of spectroelectrochemical data, indicates that a considerable repulsion exists among the adsorbed sulfate species. The spectral data were compared to those obtained for sulfate adsorption on Pt(lll) and on underpotentially deposited Ag on the Pt(111) surface. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. RP Adzic, RR (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Marinkovic, Nebojsa/A-1137-2016 OI Marinkovic, Nebojsa/0000-0003-3579-3453 NR 45 TC 31 Z9 31 U1 4 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 7 PY 1999 VL 467 IS 1-2 BP 291 EP 298 DI 10.1016/S0022-0728(99)00034-0 PG 8 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 236TE UT WOS:000082614000031 ER PT J AU Marinkovic, NS Calvente, JJ Kloss, A Kovacova, Z Fawcett, WR AF Marinkovic, NS Calvente, JJ Kloss, A Kovacova, Z Fawcett, WR TI SNIFTIRS studies of the electrochemical double layer - Part II. Au(111) electrode in solutions with specifically adsorbed nitrate ions SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE gold(111) electrode; specific adsorption; nitrate ion; IR spectroscopy ID INFRARED-SPECTROSCOPY; WATER-ADSORPTION; PT(111); SURFACES; COADSORPTION; GOLD(111); SNIFTERS; SULFATE; ANIONS AB In-situ IR reflection spectroscopy has been used to probe the structure of the double layer on an Au(111) electrode in solutions containing specifically adsorbed nitrate ions. The adsorbed nitrate ion is found to be bonded to the gold surface through one of its oxygen atoms. Both adsorbed nitrate ions, as well as those in the solution are found to possess C-2v symmetry. Nitrate ions in the double layer form contact ion-pairs with hydronium ions, possibly with an extra water molecule incorporated in the ion-pair moiety. The extent of ion-pairing is found to depend on the applied potential. An indication of the onset of water chemisorption on the gold surface is also found with the present technique. On the basis of combined ATR and SNIFTIRS (subtractively normalized interfacial Fourier transform IR spectroscopy) experiments it is shown that the width of the deconvoluted nitrate band can be used to estimate the vicinity of the potential of zero charge (pzc). It was found that the pzc in 0.01 M HNO3 is close to that observed in 0.01 M HClO4, and that it shifts by ca. -100 mV per pH unit due to the specific adsorption of nitrate. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Sevilla, Dept Quim Fis, Seville, Spain. Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. RP Marinkovic, NS (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Calvente, Juan Jose/A-8261-2008; Marinkovic, Nebojsa/A-1137-2016 OI Calvente, Juan Jose/0000-0002-4229-6204; Marinkovic, Nebojsa/0000-0003-3579-3453 NR 34 TC 19 Z9 20 U1 1 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 7 PY 1999 VL 467 IS 1-2 BP 325 EP 334 DI 10.1016/S0022-0728(99)00039-X PG 10 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 236TE UT WOS:000082614000034 ER PT J AU Lee, D Bray, PJ Aselage, TL AF Lee, D Bray, PJ Aselage, TL TI The NQR and NMR studies of icosahedral borides SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID BORON CARBIDES; RESONANCE; SPECTROSCOPY AB Boron NMR and NQR studies have been performed on three icosahedral borides: alpha- and beta-rhombohedral boron and boron carbide(B12C3). Two B-11 NMR peaks, separated by significant chemical shifts in the range from 130 ppm to 280 ppm, were clearly observed for all of the icosahedral borides that were not enriched in the B-10 isotope. A single peak, however, was found for the B-10 enriched boron carbide powder (90.6 at.% enrichment.) Moreover, the peak separation in the B-11 NMR spectrum for the unenriched beta-boron was reduced when the sample was crushed into a fine powder. In addition to NMR responses, four strong NQR responses were observed for boron carbides from different manufacturers. Two resonance signals, observed at 513 kHz and 2769 kHz, correspond to one of the icosahedral boron sites and the boron in the CBC chain, respectively. The other two NQR responses, having frequencies of 361 and 380 kHz, are either B-10 responses for the chain site or B-11 responses for the other boron sites in the icosahedra. The NQR responses are not only consistent with the previous NMR studies performed independently by Silver and Bray (1959 J. Chem. Phys. 31 247) and by Hynes and Alexander (1971 J. Chem. Phys. 54 5296, 1972 J. Chem. Phys. Erratum 56), but also provide much higher accuracy for the values of the quadrupolar parameters. C1 Brown Univ, Dept Phys, Providence, RI 02912 USA. Sandia Natl Labs, Dept 1153, Albuquerque, NM 87185 USA. RP Lee, D (reprint author), Brown Univ, Dept Phys, Box 1843, Providence, RI 02912 USA. NR 25 TC 6 Z9 6 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUN 7 PY 1999 VL 11 IS 22 BP 4435 EP 4450 DI 10.1088/0953-8984/11/22/314 PG 16 WC Physics, Condensed Matter SC Physics GA 204YR UT WOS:000080794200016 ER PT J AU Xie, JJ Chen, SP AF Xie, JJ Chen, SP TI Ab initio calculations of the structure and energetics of As-vacancy complexes in silicon SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; IMPURITY DIFFUSION; SYSTEMS; ENERGY AB For atomistic simulation of vacancy-assisted dopant diffusion in silicon one needs details of the dopant-vacancy interaction, i.e. the potential as a functional of dopant-vacancy separations. In this paper, we present a detailed study on the energetics of As-vacancy reaction in silicon and the lattice distortions surrounding the As-vacancy defect by using an ab initio plane-wave pseudopotential method and the density functional theory (DFT). A potential-energy diagram as a function of As-vacancy separation, which can be used in the atomistic diffusion simulations, is provided. We also calculate the binding: energy and the formation energy of various complexes such as AsV, As-2 V and AsV2 (V represents a vacancy). We fmd that the stable configuration of As-2 V is As-V-As, whereas the stable configuration of AsV2 is As-V-V. The nature of the binding between As and a vacancy is explained in terms of the lattice distortions and the change of chemical band configuration introduced by the As-vacancy complex. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 18 TC 19 Z9 19 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 EI 1361-6463 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD JUN 7 PY 1999 VL 32 IS 11 BP 1252 EP 1257 DI 10.1088/0022-3727/32/11/311 PG 6 WC Physics, Applied SC Physics GA 204ZQ UT WOS:000080796900011 ER PT J AU Yang, H Gao, HR Angelici, RJ AF Yang, H Gao, HR Angelici, RJ TI Hydrodefluorination of fluorobenzene and 1,2-difluorobenzene under mild conditions over rhodium pyridylphosphine and bipyridyl complexes tethered on a silica-supported palladium catalyst SO ORGANOMETALLICS LA English DT Article ID CARBON-FLUORINE BONDS; INTERMOLECULAR C-F; SATURATED PERFLUOROCARBONS; MOLECULAR-STRUCTURE; OXIDATIVE ADDITION; ACTIVATION; HEXAFLUOROBENZENE; DEFLUORINATION; CRYSTAL; ARYL AB Fluorobenzene and 1,2-difluorobenzene are defluorinated under very mild conditions by H-2 (4 atm) at 70 degrees C in the presence of NaOAc. The heterogeneous catalysts for these reactions contain the rhodium pyridylphosphine (1) and bipyridyl (2) complexes [Rh(COD)(1)]BF4 and [Rh(COD)(2)]BF4 tethered to heterogeneous Pd-SiO2. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Angelici, RJ (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 33 TC 72 Z9 73 U1 2 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUN 7 PY 1999 VL 18 IS 12 BP 2285 EP 2287 DI 10.1021/om990151e PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 206ZF UT WOS:000080910200001 ER PT J AU Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Tajima, H Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Dumas, DJ Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Henderson, S Hopman, PI Katayama, N Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, H Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, WA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lee, J Lorenc, J Schwarthoff, H Wolf, A Zoeller, RM 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 Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, S Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wano, JC Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S AF Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Tajima, H Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Dumas, DJ Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Henderson, S Hopman, PI Katayama, N Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, H Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, WA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lee, J Lorenc, J Schwarthoff, H Wolf, A Zoeller, RM 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 Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, S Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wano, JC Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S CA Cleo Collaboration TI Measurement of charm meson lifetimes SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTOR; PHYSICS AB We report measurements of the D-0, D-,(+) and D-s(+) meson lifetimes using 3.7 fb(-1) of e(+)e(-) annihilation data collected near the Y(4S) resonance with the CLEO detector. The measured lifetimes of the D-0, D+, and D-s(+) mesons are 408.5 +/- 4.1(-3.4)(+3.5) fs, 1033.6 +/- 22.1(-12.7)(+9.9) fs, and 486.3 +/- 15.0(-5.1)(+4.9) fs. The precisions of these lifetimes are comparable to those of the best previous measurements, and the systematic errors are very different. In a single experiment we find that the ratio of the D-s(+) and D-0 lifetimes is 1.19 +/- 0.04. [S0031-9007(99)09313-8]. C1 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. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Comp Devices Canada, Nepean, ON K2H 5B7, Canada. Univ Texas, Austin, TX 78712 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Cincinnati, Cincinnati, OH 45221 USA. RP Bonvicini, G (reprint author), Wayne State Univ, Detroit, MI 48202 USA. RI Warburton, Andreas/N-8028-2013; Lohner, Herbert/B-2397-2014; Briere, Roy/N-7819-2014; OI Warburton, Andreas/0000-0002-2298-7315; Lohner, Herbert/0000-0002-7441-739X; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674; Poling, Ronald/0000-0001-7305-4702 NR 10 TC 26 Z9 26 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 JUN 7 PY 1999 VL 82 IS 23 BP 4586 EP 4590 DI 10.1103/PhysRevLett.82.4586 PG 5 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300005 ER PT J AU Ginocchio, JN AF Ginocchio, JN TI Resurrection of a symmetry in nucleon-nucleus scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID PSEUDOSPIN SYMMETRY; ELASTIC-SCATTERING; POTENTIALS; STATES; PB-208 AB We reexamine a symmetry in nucleon-nucleus scattering that previously had been proclaimed to be dead. We show that this symmetry is the continuum analog of pseudospin symmetry, a relativistic symmetry which manifests itself in the spectra of nuclei. Usings experimental data only, we show that pseudospin symmetry in nucleon-nucleus scattering is not dead but only modestly broken for 800 MeV proton scattering on nuclei. [S0031-9007(99)09284-4]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ginocchio, JN (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B283, Los Alamos, NM 87545 USA. NR 27 TC 38 Z9 38 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 JUN 7 PY 1999 VL 82 IS 23 BP 4599 EP 4602 DI 10.1103/PhysRevLett.82.4599 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300008 ER PT J AU Aranson, IS Tsimring, LS AF Aranson, IS Tsimring, LS TI Dynamics of axial separation in long rotating drums SO PHYSICAL REVIEW LETTERS LA English DT Article ID GRANULAR MATERIAL; SEGREGATION AB We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultraslow logarithmic coarsening. [S0031-9007(99)09348-5]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif San Diego, Inst Nonlinear Sci, La Jolla, CA 92093 USA. RP Aranson, IS (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Aranson, Igor/I-4060-2013 NR 14 TC 47 Z9 47 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 JUN 7 PY 1999 VL 82 IS 23 BP 4643 EP 4646 DI 10.1103/PhysRevLett.82.4643 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300019 ER PT J AU Glosli, JN Ree, FH AF Glosli, JN Ree, FH TI Liquid-liquid phase transformation in carbon SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-PRESSURE; METAL TRANSITION; WATER; SIMULATIONS; DYNAMICS AB A first order phase transition is found in liquid carbon using atomistic simulation methods and Brenner's bond order potential. The phase line is terminated by a critical point at 8801 K and 10.56 GPa and by a triple point on the graphite melting line at 5133 K and 1.88 GPa. The phase change is associated with density and structural changes. The low-density liquid is predominantly sp bonded with little sp(3) character. The high-density liquid is mostly sp3 bonded with little sp character. This is the first nonempirical evidence of a liquid-liquid transition between thermodynamically stable fluids. [S0031-9007(99)08961-9]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Glosli, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 25 TC 206 Z9 208 U1 2 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 JUN 7 PY 1999 VL 82 IS 23 BP 4659 EP 4662 DI 10.1103/PhysRevLett.82.4659 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300023 ER PT J AU Pasternak, MP Rozenberg, GK Machavariani, GY Naaman, O Taylor, RD Jeanloz, R AF Pasternak, MP Rozenberg, GK Machavariani, GY Naaman, O Taylor, RD Jeanloz, R TI Breakdown of the Mott-Hubbard state in Fe2O3: A first-order insulator-metal transition with collapse of magnetism at 50 GPa SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIAMOND-ANVIL CELL; HIGH-PRESSURE; FE-57 MOSSBAUER AB Electronic and structural properties of the high-pressure phase of Fe2O3 were determined by combining the methods of Mossbauer spectroscopy, x-ray diffraction, and electrical resistance, R(P, T), to 80 GPa. Because of a first-order phase transition taking place in the 50-75 GPa range and accompanied by a volume decrease of similar to 10%, a breakdown of the electronic d-d correlation occurred, leading to a Mott transition, a metallic and a nonmagnetic single Fe3+ electronic state. The high-pressure structure is of the distorted Rh2O3-II type. The accommodation of the denser phase within this six-coordinated structure is attributable to the metallic state. [S0031-9007(99)09286-8]. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. RP Pasternak, MP (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NR 17 TC 105 Z9 105 U1 3 U2 27 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 7 PY 1999 VL 82 IS 23 BP 4663 EP 4666 DI 10.1103/PhysRevLett.82.4663 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300024 ER PT J AU Stojkovic, BP Yu, ZG Bishop, AR Castro Neto, AH Gronbech-Jensen, N AF Stojkovic, BP Yu, ZG Bishop, AR Castro Neto, AH Gronbech-Jensen, N TI Charge ordering and long-range interactions in layered transition metal oxides SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; PHASE-SEPARATION; QUANTUM ANTIFERROMAGNETS; SPIN CORRELATIONS; HUBBARD-MODEL; STRIPES; FLUCTUATIONS; LA2-XSRXCUO4; SUMMATION; MAGNETISM AB We study the competition between long-range and short-range interactions among holes within a continuum formulation of the spin density wave picture of layered transition metal oxides. We focus on the problem of charge orderings and the charge phase diagram. The main interactions are the long-range Coulomb interaction and a magnetic dipolar short-range interaction generated by short-range antiferromagnetic fluctuations. Four different phases depending on the strength of the dipolar interaction and the density of holes exist: Wigner crystal, diagonal stripes, horizontal-vertical stripes (loops). and a glassy clumped phase. The effect of temperature, disorder, and lattice effects on these phases are discussed. [S0031-9007(99)09355-2]. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. RP Stojkovic, BP (reprint author), Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. RI Yu, Z/B-5547-2009; Castro Neto, Antonio/C-8363-2014; OI Castro Neto, Antonio/0000-0003-0613-4010; , Zhi-Gang/0000-0002-1376-9025 NR 37 TC 56 Z9 56 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 7 PY 1999 VL 82 IS 23 BP 4679 EP 4682 DI 10.1103/PhysRevLett.82.4679 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300028 ER PT J AU Janko, B AF Janko, B TI Theory of scanning tunneling spectroscopy of magnetic-field-induced discrete nodal states in a d-wave superconductor SO PHYSICAL REVIEW LETTERS LA English DT Article ID II SUPERCONDUCTORS; VORTEX-CORE; BI2SR2CACU2O8; CONDUCTIVITY; D(X2-Y2); ENERGY; LINES AB In the presence of an external magnetic field, the low lying elementary excitations of a d-wave superconductor have quantized energy and their momenta are locked near the node direction. It is argued that these discrete states can most likely be detected by a local probe, such as a scanning tunneling microscope. The low temperature local tunneling conductance on the Wigner-Seitz cell boundaries of the vortex lattice is predicted to show peaks spaced as +/- root n, n = {0, 1,2,...}. Away from the cell boundary, where the superfluid velocity is nonzero, each peak splits, in general, into four peaks, corresponding to the number of nodes in the order parameter. [S0031-9007(99)09303-5]. C1 Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Janko, B (reprint author), Argonne Natl Lab, Div Sci Mat, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 34 TC 12 Z9 12 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 7 PY 1999 VL 82 IS 23 BP 4703 EP 4706 DI 10.1103/PhysRevLett.82.4703 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300034 ER PT J AU Bao, W Raymond, S Shapiro, SM Motoya, K Fak, B Erwin, RW AF Bao, W Raymond, S Shapiro, SM Motoya, K Fak, B Erwin, RW TI Unconventional ferromagnetic and spin-glass states of the reentrant spin glass Fe0.7Al0.3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRON-SCATTERING; DYNAMICS; ALLOYS; COEXISTENCE; TRANSITION; BEHAVIOR; FEXCR1-X AB Spin excitations in a single crystal of Fe0.7Al0.3 were investigated over a wide range pf energy and reciprocal space with inelastic neutron scattering. In the ferromagnetic phase, propagating spin wave modes become paramagnonlike diffusive modes beyond a critical wave vector q(0), indicating substantial disorder in the long-range ordered state. In the spin glass phase, the spin dynamics are strongly q dependent, suggesting remnant short-range spin correlations. [S0031-9007(99)09306-0]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CEA Grenoble, DRFMC, SPSMS, F-38054 Grenoble, France. Sci Univ Tokyo, Noda, Chiba 278, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bao, W (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Bao, Wei/E-9988-2011 OI Bao, Wei/0000-0002-2105-461X NR 32 TC 42 Z9 42 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 JUN 7 PY 1999 VL 82 IS 23 BP 4711 EP 4714 DI 10.1103/PhysRevLett.82.4711 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300036 ER PT J AU Miller, BH Stojkovic, BP Dahlberg, ED AF Miller, BH Stojkovic, BP Dahlberg, ED TI Universal relationship between giant magnetoresistance and anisotropic magnetoresistance in spin valve multilayers SO PHYSICS LETTERS A LA English DT Article ID LAYERED MAGNETIC-STRUCTURES; ENHANCED MAGNETORESISTANCE; DEPENDENT SCATTERING; SUPERLATTICES AB We measure the giant magnetoresistance (GMR) with the current both parallel and perpendicular to the direction of the magnetization in the ferromagnetic (FM) layers and thus probe the anisotropy of the effective mean free paths for the spin-up and spin-down electrons, seen in the anisotropic magnetoresistance. We find that the difference of the GMR in the two configurations, when expressed in terms of the sheet conductance, displays a nearly universal behavior as a function of GMR. On interpreting the results within the Boltzmann transport formalism we demonstrate the importance of bulk scattering for GMR. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Miller, BH (reprint author), Seagate Technol, MS NRE 240,1 Disc Dr, Minneapolis, MN 55435 USA. NR 23 TC 4 Z9 4 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUN 7 PY 1999 VL 256 IS 4 BP 294 EP 298 DI 10.1016/S0375-9601(99)00166-8 PG 5 WC Physics, Multidisciplinary SC Physics GA 205CA UT WOS:000080802700009 ER PT J AU Crawford, CL Barnes, MJ Peterson, RA Wilmarth, WR Hyder, ML AF Crawford, CL Barnes, MJ Peterson, RA Wilmarth, WR Hyder, ML TI Copper-catalyzed sodium tetraphenylborate, triphenylborane, diphenylborinic acid and phenylboronic acid decomposition kinetic studies in aqueous alkaline solutions SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE copper-catalyzed decomposition; sodium tetraphenylborate; triphenylborane; diphenylborinic acid; phenylboronic acid; kinetics ID PULSE-RADIOLYSIS AB This work studied the kinetics of copper-catalyzed decomposition of tetraphenylborate, triphenylborane, diphenylborinic acid and phenylboronic acid (NaTPB, 3PB, 2PB and 1PB, respectively) in aqueous alkaline solution over the temperature range of 25 to 70 degrees C. The statistically designed test matrices added copper sulfate to maximum concentrations of 10 mg/l. The relative rates of decomposition increase in the order NaTPB < 1PB similar to 3PB < 2PB. Dependence of decomposition on the amount of added copper increases in the order 3PB similar to 2PB < 1PB similar to NaTPB. Activation energies ranged from 82 to 143 kJ mol(-1) over the temperature range studied. Final decomposition products involved benzene and phenol predominately. All 3PB, 2PB and 1PB intermediate phenylborate species proved relatively stable (< 8% decomposition over ca. 500 h) towards thermal hydrolysis in 1.5 M NaOH when contained in carbon-steel vessels sealed under air at ambient temperature (23-25 degrees C) with no added copper. Measurable (> 10(-7) M h(-1)) thermal hydrolysis of the phenylborate species occurs at 55 to 70 degrees C in alkaline (0.6-2.3 M OH-, 2-4.7 M Na+) solution with no added copper. The experiments suggest an important role for oxygen in copper-catalyzed phenylborate decomposition. NaTPB decomposes promptly under anoxic conditions while 3PB. 2PB and 1PB decompose faster in aerobic solutions. Benzene and phenol form as the predominant end-products from alkaline copper catalysis in static systems sealed under air. Both 2PB and 1PB decompose with near equal rates and quantitatively produce phenol under flowing air-purge conditions at 25-60 degrees C. Mechanisms for copper-catalyzed phenylborate decomposition likely involve a redox process giving loss of a phenyl group from the phenylborate with reduction of cupric ion, or dephenylation by reduced cuprous ion involving a phenylated copper intermediate. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science S.A. All rights reserved. C1 Westinghouse Savannah River Co, Aiken, SC 29808 USA. RP Barnes, MJ (reprint author), Westinghouse Savannah River Co, Savannah River Site, Aiken, SC 29808 USA. OI Peterson, Reid/0000-0003-3368-1896 NR 42 TC 17 Z9 18 U1 0 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD JUN 5 PY 1999 VL 581 IS 1-2 BP 194 EP 206 DI 10.1016/S0022-328X(99)00065-0 PG 13 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 207HP UT WOS:000080931700024 ER PT J AU Taatjes, CA AF Taatjes, CA TI Infrared frequency-modulation measurements of absolute rate coefficients for Cl+HD -> HCl(DCl)+D(H) between 295 and 700 K SO CHEMICAL PHYSICS LETTERS LA English DT Article ID THERMAL RATE-CONSTANT; REACTIVE SCATTERING; BRANCHING RATIO; DYNAMICS; KINETICS; HYDROGEN; CL+H-2; HD; SPECTROSCOPY; ABSTRACTION AB Absolute rate coefficients and HCl branching fractions for the Cl + HD reaction have been measured. The rate coefficient for Cl + HD is fit well by k(1) = (1.28 +/- 0.18) x 10(-16) T-1.67 e(-(1646) (+/- 60)/T) cm(3) molecule(-1) s(-1), approximately 30% smaller than the mean of literature rate coefficients for Cl + H-2 and D-2. The branching fraction into the HCl channel is 0.67 +/- 0.09 at 295 K and decreases at higher temperature. The present results agree well with literature measurements of relative rates, confirming different isotope effects in thermal conditions than in molecular beam measurements. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Taatjes, CA (reprint author), Sandia Natl Labs, Combust Res Facil, Mail Stop 9055, Livermore, CA 94551 USA. NR 34 TC 22 Z9 22 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 JUN 4 PY 1999 VL 306 IS 1-2 BP 33 EP 40 DI 10.1016/S0009-2614(99)00420-0 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 205HH UT WOS:000080814900005 ER PT J AU Kaledin, AL Heaven, MC Morokuma, K Neumark, DM AF Kaledin, AL Heaven, MC Morokuma, K Neumark, DM TI Cl-3(-) electron photodetachment spectrum: measurement and assignment SO CHEMICAL PHYSICS LETTERS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; GAUSSIAN-BASIS SETS; AB-INITIO; MOLECULAR CALCULATIONS; ION; CL; EMISSION; STATES; ATOMS; X=F AB An electron photodetachment spectrum of Cl-3(-) is reported for 193 nm (6.42 eV) excitation. The spectrum was assigned using high-level ab initio calculation for the Cl-3 radical and the Cl-3(-) ion. A broad band centered around 1.25 eV (electron kinetic energy) has been assigned to the Cl-3(-)(X (1)Sigma(g)(+)) --> Cl-3(X (2)Pi(u)) and Cl3(1 (2)Sigma(g)(+)) transitions. Vertical photodetachment accesses the transition state region for the Cl exchange reaction: Cl + Cl-2 --> Cl-2 + Cl. A narrow doubler hand at 0.55 eV is assigned to the Cl-3(-)(X (1)Sigma(g)(+)) --> Cl3(1 (2)Pi(g)) transition, split by spin-orbit interaction. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Emory Univ, Cherry L Emerson Ctr Sci Comp, Atlanta, GA 30322 USA. Emory Univ, Dept Chem, Atlanta, GA 30322 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Emory Univ, Cherry L Emerson Ctr Sci Comp, Atlanta, GA 30322 USA. EM morokuma@emory.edu RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 25 TC 4 Z9 4 U1 0 U2 1 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 JUN 4 PY 1999 VL 306 IS 1-2 BP 48 EP 52 DI 10.1016/S0009-2614(99)00419-4 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 205HH UT WOS:000080814900007 ER PT J AU Xie, XS Lu, HP AF Xie, XS Lu, HP TI Single-molecule enzymology SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Review ID FLUORESCENCE CORRELATION SPECTROSCOPY; ENZYME; KINETICS; DYNAMICS; FLUCTUATIONS; PROTEINS; DIAGNOSTICS; MICROSCOPY; CATALYSIS; BEHAVIOR C1 Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Xie, XS (reprint author), Harvard Univ, Dept Chem & Chem Biol, 12 Oxford St, Cambridge, MA 02138 USA. NR 51 TC 200 Z9 205 U1 3 U2 38 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 JUN 4 PY 1999 VL 274 IS 23 BP 15967 EP 15970 DI 10.1074/jbc.274.23.15967 PG 4 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 202TQ UT WOS:000080668600001 PM 10347141 ER PT J AU Ma, CY McCorkle, DL Ding, WX Pinnaduwage, LA AF Ma, CY McCorkle, DL Ding, WX Pinnaduwage, LA TI Methodology for gas chromatographic-mass spectral analysis of volatile organic compounds emerging from a low-pressure, flow-through reaction cell SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE instrumentation; sample handling; volatile organic compounds; benzene; methylene chloride ID HEADSPACE SAMPLES; AIR; GC AB A methodology has been developed for the analysis of volatile organic compounds (VOCs) emerging from a plasma discharge cell operating at a constant flow-rate under subatmospheric pressure (0.266 to 2.66 kPa). The analytical system consisted of a gas reservoir for trapping a portion of the VOC-rare gas mixture, a sampling loop for cryogenically concentrating the VOC products, and either gas chromatography-mass spectrometry (GC-MS) or gas chromatography-flame ionization detection (GC-FID). The methodology was evaluated for the analysis of methylene chloride, benzene and tetrachloroethylene, using n-octane as the internal standard. Calibration curves were constructed by plotting the pressure ratios of the gas standard relative to the internal standard versus the corresponding peak area ratios. Over a pressure range of 1.133 to 5.32 kPa, the linearity of the calibration curve for each gas standard was determined with correlation coefficients ranging from 0.96 to 0.98. The relative standard deviation for a minimum of triplicate analyses varied from 1.1 to 18.3% for most VOCs. The calibration curves were used to measure the concentration of premixed VOC-rare gas mixtures as a function of energy input of the plasma reactor. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Ma, CY (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 20 TC 2 Z9 2 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD JUN 4 PY 1999 VL 844 IS 1-2 BP 217 EP 224 DI 10.1016/S0021-9673(99)00270-8 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 210DT UT WOS:000081090400019 ER PT J AU Belz, J Diwan, M Eckhause, M Guss, CM Hancock, AD Heinson, AP Highland, VL Hoffmann, GW Irwin, GM Kane, JR Kettell, SH Kuang, Y Lang, K McDonough, J McFarlane, WK Molzon, WR Riley, PJ Ritchie, JL Schwartz, AJ Ware, B Welsh, RE Winter, RG Witkowski, M Wojcicki, SG Worm, SD Yamashita, A AF Belz, J Diwan, M Eckhause, M Guss, CM Hancock, AD Heinson, AP Highland, VL Hoffmann, GW Irwin, GM Kane, JR Kettell, SH Kuang, Y Lang, K McDonough, J McFarlane, WK Molzon, WR Riley, PJ Ritchie, JL Schwartz, AJ Ware, B Welsh, RE Winter, RG Witkowski, M Wojcicki, SG Worm, SD Yamashita, A TI A compact beam stop for a rare kaon decay experiment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE hadronic absorber; beam dump; cascade simulation ID NEUTRON AB We describe the development and testing of a novel beam stop for use in a rare kaon decay experiment at the Brookhaven Alternating Gradient Synchrotron. The beam stop is located inside a dipole spectrometer magnet in close proximity to straw drift chambers and intercepts a high-intensity neutral hadron beam. The design process, involving both Monte Carlo simulations and beam tests of alternative beam-stop shielding arrangements, had the goal of minimizing the leakage of particles from the beam stop and the resulting kit rates in detectors, while preserving maximum acceptance for events of interest. The beam tests consisted of measurements of rates in drift chambers, scintillation counter hodoscopes, a gas threshold Cherenkov counter, and a lead glass array. Measurements were also made with a set of specialized detectors which were sensitive to low-energy neutrons, photons, and charged particles. Comparisons are made between these measurements and a detailed Monte Carlo simulation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Temple Univ, Philadelphia, PA 19122 USA. Stanford Univ, Stanford, CA 94309 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Univ Calif Irvine, Irvine, CA 92717 USA. Univ Texas, Austin, TX 78712 USA. RP Worm, SD (reprint author), Fermilab, MS-318,POB 500, Batavia, IL 60510 USA. OI Heinson, Ann/0000-0003-4209-6146 NR 25 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 4 PY 1999 VL 428 IS 2-3 BP 239 EP 262 DI 10.1016/S0168-9002(98)01381-3 PG 24 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 206QK UT WOS:000080890400001 ER EF