FN Thomson Reuters Web of Science™ VR 1.0 PT J AU MCFARLAND, AR RODGERS, JC ORTIZ, CA MOORE, ME AF MCFARLAND, AR RODGERS, JC ORTIZ, CA MOORE, ME TI A CONTINUOUS SAMPLER WITH BACKGROUND SUPPRESSION FOR MONITORING ALPHA-EMITTING AEROSOL-PARTICLES SO HEALTH PHYSICS LA English DT Article DE AEROSOLS; RADIATION MONITORS; ALPHA PARTICLES; SAMPLING AB A continuous air monitor has been developed that includes provisions for improving the detection of alpha-emitting aerosol particles in the presence of radon/thoron progeny that are unattached to ambient aerosol particles. Wind tunnel tests show that 80% of 10-mu-m aerodynamic equivalent diameter particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L min-1 (2 cfm) and the wind speed is 1 m s-1. Uniformity of aerosol collection on the filter, as characterized by the coefficient of variation of the areal density deposits, is < 15% for 10-mu-m aerodynamic-equivalent-diameter aerosol particles. Tests with unattached radon daughters in a flow-through chamber showed that approximately 99% of the Po-218 was removed by an inlet screen that is designed to collect radon daughters that are in the size range of molecular clusters. The inlet screen offers the opportunity to improve the signal-to-noise ratio of energy spectra in the regions of interest (subranges of the energy spectrum) of transuranic elements and thereby enhance the performance of background compensation algorithms. C1 UNIV CALIF LOS ALAMOS SCI LAB, MEASUREMENTS TECHNOL SUPPORT SECT, HLTH PHYS MEASUREMENTS GRP HSE4, LOS ALAMOS, NM 87545 USA. RP MCFARLAND, AR (reprint author), TEXAS A&M UNIV SYST, DEPT MECH ENGN, AEROSOL TECHNOL LAB, COLLEGE STN, TX 77843 USA. NR 21 TC 11 Z9 12 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 MAY PY 1992 VL 62 IS 5 BP 400 EP 406 DI 10.1097/00004032-199205000-00003 PG 7 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA HP673 UT WOS:A1992HP67300003 PM 1559808 ER PT J AU HOFFMAN, FO THIESSEN, KM FRANK, ML BLAYLOCK, BG AF HOFFMAN, FO THIESSEN, KM FRANK, ML BLAYLOCK, BG TI DETERMINING THE COLLECTION EFFICIENCY OF GUMMED PAPER FOR THE DEPOSITION OF RADIOACTIVE CONTAMINANTS IN SIMULATED RAIN SO HEALTH PHYSICS LA English DT Note DE FALLOUT; RADIOACTIVITY, AIRBORNE; CONTAMINATION, ENVIRONMENTAL; MONITORING, AIR AB An extensive network of gummed paper collectors was used during the 1950s for routine monitoring of radioactive fallout from weapons testing. The experiments reported in this paper were designed to examine the collection efficiency of gummed paper for wet deposition of several types of soluble and insoluble radioactive contaminants under conditions similar to those found during natural rainstorms. The collection efficiencies for each substance were determined over a range of rainfall amounts and at two separate rainfall intensities. The collection efficiency of the gummed paper is highest for large insoluble particles and lowest for soluble ionic substances. The values for Be-7 and I-131 ranged from about 0.30 (30%) at 2.5 mm of rain to 0.04-0.06 (4%-6%) at 20 mm of rain. These values were negatively correlated with the amount of rain and were unaffected by rain intensity. This suggests that the collection efficiency of either ion is simply a matter of rapid saturation and runoff. Neither rain amount nor rain intensity has much effect on the collection efficiency of large insoluble particles. These particles seem to settle readily onto the surface of the gummed paper from which they are not easily removed by additional rain. Analysis of the collection efficiencies of the gummed paper included the activity of both the gummed paper and the standing water on the paper. A large portion of the activity for the ionic substances was found in the standing water. There was less activity by insoluble particles in standing water. This indicates that for estimates of deposition of soluble substances, considerable bias could be introduced into the results if the standing water is discarded prior to analysis. RP HOFFMAN, FO (reprint author), OAK RIDGE NATL LAB, DIV ENVIRONM SCI, OAK RIDGE, TN 37831 USA. FU PHS HHS [485-1737-A1] NR 3 TC 4 Z9 4 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 MAY PY 1992 VL 62 IS 5 BP 439 EP 442 DI 10.1097/00004032-199205000-00009 PG 4 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA HP673 UT WOS:A1992HP67300009 PM 1559814 ER PT J AU SCHWARTZ, JL ROTMENSCH, J ATCHER, RW JOSTES, RF CROSS, FT HUI, TE CHEN, D CARPENTER, S EVANS, HH MENCL, J BAKALE, G RAO, PS AF SCHWARTZ, JL ROTMENSCH, J ATCHER, RW JOSTES, RF CROSS, FT HUI, TE CHEN, D CARPENTER, S EVANS, HH MENCL, J BAKALE, G RAO, PS TI INTERLABORATORY COMPARISON OF DIFFERENT ALPHA-PARTICLE AND RADON SOURCES - CELL-SURVIVAL AND RELATIVE BIOLOGICAL EFFECTIVENESS SO HEALTH PHYSICS LA English DT Note DE RADON; RELATIVE BIOLOGICAL EFFECTIVENESS; ALPHA-PARTICLES; DOSIMETRY, ALPHA ID MUTAGENICITY; REPAIR; PU-238 AB Alpha radiation-induced cell killing was determined in four different laboratories in order to: 1) measure interlaboratory variability and 2) compare the effects of radon and radon daughter exposures with the effects of Pu-238 (an often-used model for radon exposure). The results suggest that differences in handling from laboratory to laboratory can affect both low and high linear energy transfer responses and should be considered when comparing results from different laboratories. C1 UNIV CHICAGO, DEPT RADIAT & CELLULAR ONCOL, CHICAGO, IL 60637 USA. ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. PACIFIC NW LAB, DEPT BIOL & CHEM, RICHLAND, WA 99352 USA. PACIFIC NW LAB, DEPT HLTH PHYS, RICHLAND, WA 99352 USA. UNIV CALIF LOS ALAMOS SCI LAB, GENET GRP, LOS ALAMOS, NM 87545 USA. CASE WESTERN RESERVE UNIV, DEPT RADIOL, CLEVELAND, OH 44106 USA. RP SCHWARTZ, JL (reprint author), ARGONNE NATL LAB, DIV BIOL & MED RES, ARGONNE, IL 60439 USA. OI Atcher, Robert/0000-0003-4656-2247 FU NCI NIH HHS [P30 CA43703] NR 14 TC 24 Z9 24 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 MAY PY 1992 VL 62 IS 5 BP 458 EP 461 DI 10.1097/00004032-199205000-00014 PG 4 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA HP673 UT WOS:A1992HP67300014 PM 1559819 ER PT J AU WERNICKE, JC AF WERNICKE, JC TI LANDFILL AS OPTION TO RECYCLING SO HYDROCARBON PROCESSING LA English DT Letter RP WERNICKE, JC (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU GULF PUBL CO PI HOUSTON PA BOX 2608, HOUSTON, TX 77252-2608 SN 0018-8190 J9 HYDROCARB PROCESS JI Hydrocarb. Process. PD MAY PY 1992 VL 71 IS 5 BP 44 EP 45 PG 2 WC Energy & Fuels; Engineering, Chemical; Engineering, Petroleum SC Energy & Fuels; Engineering GA HW755 UT WOS:A1992HW75500008 ER PT J AU CHU, TL CHU, SS BRITT, J FEREKIDES, C WANG, C WU, CQ ULLAL, HS AF CHU, TL CHU, SS BRITT, J FEREKIDES, C WANG, C WU, CQ ULLAL, HS TI 14.6-PERCENT EFFICIENT THIN-FILM CADMIUM TELLURIDE HETEROJUNCTION SOLAR-CELLS SO IEEE ELECTRON DEVICE LETTERS LA English DT Article AB Thin-film cadium sulfide/cadium telluride (CdS/CdTe) heterojunction solar cells have been prepared by the successive deposition of thin films of fluorine-doped SnO2, CdS, p-CdTe, and an ohmic contact on glass substrates, followed by the deposition of an antireflection coating. The properties of CdS/CdTe heterojunctions have been studied. Under global AM 1.5 conditions, a solar cell of about 1-cm2 area has an open-circuit voltage of 805 +/- 5 mV, a short-circuit current density of 24.4 +/- 0.3 mA/cm2, and a fill factor of (70.5 +/- 0.5)%, corresponding to a total area conversion efficiency of (14.6 +/- 0.3)%, verified by the National Renewable Energy Laboratory. C1 UNIV S FLORIDA,DEPT ELECT ENGN,TAMPA,FL 33620. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 5 TC 82 Z9 84 U1 2 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD MAY PY 1992 VL 13 IS 5 BP 303 EP 304 DI 10.1109/55.145061 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA HQ605 UT WOS:A1992HQ60500026 ER PT J AU HOFMANN, T SHARP, TE DANE, CB WISOFF, PJ WILSON, WL TITTEL, FK SZABO, G AF HOFMANN, T SHARP, TE DANE, CB WISOFF, PJ WILSON, WL TITTEL, FK SZABO, G TI CHARACTERIZATION OF AN ULTRAHIGH PEAK POWER XEF(C -] A) EXCIMER LASER SYSTEM SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID 248 NM; XECL; PULSES; AMPLIFICATION; GENERATION; KRF AB The gain characteristics of an electron-beam pumped XeF(C --> A) excimer amplifier operating in the blue-green spectral region were investigated for several laser pulse lengths. Saturation energy densities of 50 and 80 mJ/cm2 were measured for injected laser pulse durations of 250 fs and approximately 100 ps, respectively. A gain bandwidth of 60 nm was observed with approximately 100 ps pulse injection. Using an optimized unstable resonator design, the laser amplifier has produced 275 mJ pulses with a pulse duration of 250 fs and a 2.5 times diffraction limited beam quality, making the XeF(C --> A) amplifier the first compact laser system in the visible spectral region to reach peak powers at the terawatt level. C1 JATE UNIV,DEPT OPT & QUANTUM ELECTR,SZEGED,HUNGARY. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP HOFMANN, T (reprint author), RICE UNIV,DEPT ELECT & COMP ENGN,HOUSTON,TX 77251, USA. RI Clement, Tracy/A-8885-2008 NR 29 TC 27 Z9 27 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAY PY 1992 VL 28 IS 5 BP 1366 EP 1375 DI 10.1109/3.135279 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA HT023 UT WOS:A1992HT02300020 ER PT J AU CHIKOFSKY, EJ MARTIN, DE CHANG, H AF CHIKOFSKY, EJ MARTIN, DE CHANG, H TI ASSESSING THE STATE OF TOOLS ASSESSMENT SO IEEE SOFTWARE LA English DT Editorial Material C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL. AT&T BELL LABS,MURRAY HILL,NJ 07974. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD MAY PY 1992 VL 9 IS 3 BP 18 EP 21 PG 4 WC Computer Science, Software Engineering SC Computer Science GA HQ443 UT WOS:A1992HQ44300007 ER PT J AU NICINSKI, T AF NICINSKI, T TI EXTENDING TEAMWORK FOR ARCHITECTURE DIAGRAMS SO IEEE SOFTWARE LA English DT Article RP NICINSKI, T (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD MAY PY 1992 VL 9 IS 3 BP 54 EP 60 DI 10.1109/52.136168 PG 7 WC Computer Science, Software Engineering SC Computer Science GA HQ443 UT WOS:A1992HQ44300012 ER PT J AU STROBL, K GOLUB, I AF STROBL, K GOLUB, I TI A SIMPLE ALL-OPTICAL LIGHT SWITCH AND ITS RELATIONS TO OPTICAL COMPUTING - A DEMONSTRATION FOR TEACHING PHOTONICS SO IEEE TRANSACTIONS ON EDUCATION LA English DT Article ID NONLINEAR INTERFACE AB It is generally believed that, ultimately, photonics will outperform electronics in the area of ultrafast switching and computing. Today's student will help develop the necessary elements to make optical computing possible in tomorrow's world. In this paper, we discuss how a simple and inexpensive all-optical light switch can be built for teaching and demonstrating photonics in a classroom or for undergraduate lab experiments. The discussion of this readily understandable device will familiarize the student with the similarities and differences between photonics and electronics. As an example, we consider how this device relates to all-optical computing circuits, promoting a comparison between electronic and optical integrated circuits. RP STROBL, K (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP CLS-5,MS E535,LOS ALAMOS,NM 87545, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9359 J9 IEEE T EDUC JI IEEE Trans. Educ. PD MAY PY 1992 VL 35 IS 2 BP 115 EP 121 DI 10.1109/13.135575 PG 7 WC Education, Scientific Disciplines; Engineering, Electrical & Electronic SC Education & Educational Research; Engineering GA HU436 UT WOS:A1992HU43600005 ER PT J AU ULA, N COOPER, GA DAVIDSON, JC SWIERKOWSKI, SP HUNT, CE AF ULA, N COOPER, GA DAVIDSON, JC SWIERKOWSKI, SP HUNT, CE TI OPTIMIZATION OF THIN-FILM RESISTIVE-GATE AND CAPACTIVE-GATE GAAS CHARGE-COUPLED-DEVICES SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID CCD; CIRCUITS; ANALOG AB Computer simulation of high-speed gallium arsenide charge coupled devices is performed using a two-dimensional semiconductor device simulation program. The measured performance of fabricated GaAs CCD's is compared with modeled results. The effect of active layer thickness and doping concentration on the charge transfer efficiency (CTE) and the dynamic range is investigated using different layers. Various gate architectures are compared for optimum dynamic range and compatibility with GaAs MESFET technology. The effect of clock shape on CTE is studied. Sensitivity analysis is performed on output structures. Both capacitive-gate CCD (CGCCD) and resistive-gate CCD (RGCCD) techniques are considered. C1 UNIV CALIF DAVIS,DEPT ELECT ENGN & COMP SCI,DAVIS,CA 95616. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ENGN RES,SOLID STATE DEVICES & MICROSTRUCT GRP,LIVERMORE,CA 94550. NR 37 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 1992 VL 39 IS 5 BP 1032 EP 1040 DI 10.1109/16.129079 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA HP269 UT WOS:A1992HP26900003 ER PT J AU BERENDES, T SENGUPTA, SK WELCH, RM WIELICKI, BA NAVAR, M AF BERENDES, T SENGUPTA, SK WELCH, RM WIELICKI, BA NAVAR, M TI CUMULUS CLOUD-BASE HEIGHT ESTIMATION FROM HIGH SPATIAL-RESOLUTION LANDSAT DATA - A HOUGH TRANSFORM APPROACH SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SATELLITE DATA; SURFACE AB Cloud base height is an essential variable governing surface energy budgets, but it is notoriously difficult to determine using satellite data. This study develops a semiautomated methodology to estimate cumulus cloud base heights using high spatial resolution LANDSAT Multispectral Scanner data. The approach employs a variety of image processing techniques to match cloud edges with their corresponding shadow edges. Cloud base height then is estimated by computing the separation distance between the corresponding Generalized Hough Transform reference points. Sixteen subregions, each 30 km x 30 km in size, are selected for four LANDSAT scenes. Standard deviations of cloud base height within each of the subregions range from about 100 m to 150 m. Differences between cloud base heights computed using the Hough Transform and a manual verification technique are small (on the order of 100 m or less). The cloud base heights also compare favorably with the few surface observations available. On the basis of these results, it is estimated that cloud base height accuracies of 50-70 m may be possible using HIRIS and ASTER instruments in the EOS Global Climate Change program. C1 LAWRENCE LIVERMORE NATL LAB,LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. USN,OCEANOG & ATMOSPHER RES LAB,MONTEREY,CA 93943. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP BERENDES, T (reprint author), S DAKOTA SCH MINES & TECHNOL,INST ATMOSPHER SCI,RAPID CITY,SD 57701, USA. NR 24 TC 19 Z9 19 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1992 VL 30 IS 3 BP 430 EP 443 DI 10.1109/36.142921 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA JA318 UT WOS:A1992JA31800002 ER PT J AU JENSEN, CC PROFUMO, F LIPO, TA AF JENSEN, CC PROFUMO, F LIPO, TA TI A LOW-LOSS PERMANENT-MAGNET BRUSHLESS DC MOTOR UTILIZING TAPE WOUND AMORPHOUS IRON SO IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS LA English DT Article AB An axial field permanent-magnet brushless dc motor that utilizes tape-wound amorphous iron and an air-gap winding is proposed. Simplified waveforms and performance equations for this type of machine are presented. The machine equations and waveforms are verified with a proof-of-concept machine. No-load iron losses are compared with manufacturers data, and full-load iron losses are also presented. Output torque for rectangular and trapezoidal current waveforms are measured and compared. Machine designs from a computer program that demonstrate the possible benefits of this type of machine are presented. It is suggested that this type of machine could be considerably more efficient than induction machines and, additionally, cost competitive when a variable-speed drive is already a system requirement. C1 POLITECN TORINO, DEPT ELECT ENGN, I-10128 TURIN, ITALY. UNIV WISCONSIN, DEPT ELECT & COMP ENGN, MADISON, WI 53706 USA. RP JENSEN, CC (reprint author), FERMI NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. NR 7 TC 30 Z9 30 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-9994 J9 IEEE T IND APPL JI IEEE Trans. Ind. Appl. PD MAY-JUN PY 1992 VL 28 IS 3 BP 646 EP 651 DI 10.1109/28.137452 PG 6 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA HV432 UT WOS:A1992HV43200023 ER PT J AU BUCHER, IY CALAHAN, DA AF BUCHER, IY CALAHAN, DA TI MODELS OF ACCESS DELAYS IN MULTIPROCESSOR MEMORIES SO IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS LA English DT Article DE INTERLEAVED MEMORIES; MEMORY ACCESS DELAYS; MULTIPROCESSOR MEMORIES; PARALLEL COMPUTERS; QUEUING MODELS; SIMULATIONS; VECTOR COMPUTERS ID COMPUTER AB The performance of an interleaved common memory accessed uniformly by multiple processors is modeled by queueing and simulation methods. The model includes access conflicts at the bank level while assuming an ideal access network. A general scaling law is derived that indicates that memory access delays are given by the product of the bank reservation time and a function of the memory utilization, which is the average number of access requests arriving at a bank per bank reservation time. For light, uniform memory traffic, access delays are proportional to the square of the bank reservation time and to the ratio of the number of active memory access streams to the number of memory banks. With an assumption of random access patterns, an open and a closed queueing model are developed. To model pipelined access operations, a new negative feedback model is introduced that includes the open and the closed models as special cases and is also well suited for modeling linked access streams. Delay dependence on bank reservation time is quadratic for light loads and linear for very heavy loads. The queueing models are validated by simulations. C1 UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109. RP BUCHER, IY (reprint author), LOS ALAMOS NATL LAB,COMP RES GRP,LOS ALAMOS,NM 87545, USA. RI Bucher, Izhak/I-5309-2012 NR 14 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1045-9219 J9 IEEE T PARALL DISTR JI IEEE Trans. Parallel Distrib. Syst. PD MAY PY 1992 VL 3 IS 3 BP 270 EP 280 DI 10.1109/71.139201 PG 11 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA HV826 UT WOS:A1992HV82600002 ER PT J AU BOUNOU, M LEFEBVRE, S MALHAME, RP TRUDNOWSKI, DJ AF BOUNOU, M LEFEBVRE, S MALHAME, RP TRUDNOWSKI, DJ TI A SPECTRAL ALGORITHM FOR EXTRACTING POWER-SYSTEM MODES FROM TIME RECORDINGS SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article AB This paper presents a new technique for extracting power system modes contained in a recorded time signal. The technique is based on spectral analysis and uses the Z-transform identification algorithm of Corinthios. It permits identification of the damping factor and the frequency of the modal signal components and it is computationally attractive due to efficient Fast Fourier Transform (FFT) algorithms. Signals containing multiple modes, which may be relatively close or unstable, can be handled by the technique. The paper outlines the theory behind the spectral algorithm, and it presents several examples. Advantages and weaknesses of the technique are discussed. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. INST RECH HYDRO QUEBEC, VARENNES, QUEBEC, CANADA. RP BOUNOU, M (reprint author), ECOLE POLYTECH, DEPT ELECT ENGN, MONTREAL H3C 3A7, QUEBEC, CANADA. NR 14 TC 15 Z9 17 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD MAY PY 1992 VL 7 IS 2 BP 665 EP 672 DI 10.1109/59.141772 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA HN891 UT WOS:A1992HN89100025 ER PT J AU SCHRYVER, JC AF SCHRYVER, JC TI OBJECT-ORIENTED QUALITATIVE SIMULATION OF HUMAN MENTAL MODELS OF COMPLEX-SYSTEMS SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS LA English DT Article ID KNOWLEDGE AB A qualitative model of an expert's mental model of a complex system (advanced nuclear power plant) was developed from the qualitative physics of confluences. This model was implemented as a qualitative simulation using an object-oriented extension to Common Lisp (Flavors). An existing method for dynamic constraint satisfaction was found to be inadequate for complex systems. Invisible connections for flow compatibility, control connections, iterative propagation, and embedded propagation were among the new features provided for derivation of causal ordering. Deterministic output was guaranteed through stochastic state transition. A parametric Monte Carlo simulation study was performed using a fictitious loop fragment, and changes were observed in flow rate change through a pump. State transition models provided excellent fits to the simulation data. Analysis of the state models showed that all conditions converged to steady state. Strictly forward (with the flow) propagation facilitated consistency within intermediate pre-equilibrium states and convergence as compared to forward propagation with limited backward propagation. Uncertainty bias inhibited propagation of premature incorrect values. The psychological plausibility of qualitative simulation models was evaluated. A further extension of mythical causality is suggested, for which constraint propagation executes on multiple levels of aggregation. RP SCHRYVER, JC (reprint author), OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,COGNIT SYST & HUMAN FACTORS GRP,OAK RIDGE,TN 37831, USA. NR 23 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9472 J9 IEEE T SYST MAN CYB JI IEEE Trans. Syst. Man Cybern. PD MAY-JUN PY 1992 VL 22 IS 3 BP 526 EP 541 DI 10.1109/21.155952 PG 16 WC Computer Science, Cybernetics; Engineering, Electrical & Electronic SC Computer Science; Engineering GA JJ363 UT WOS:A1992JJ36300011 ER PT J AU MILLER, JA MELIUS, CF AF MILLER, JA MELIUS, CF TI A THEORETICAL-ANALYSIS OF THE REACTION BETWEEN HYDROGEN-ATOMS AND ISOCYANIC ACID SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID EXHAUST-GAS; KINETICS; NCO AB Using BAC-MP4 potential-surface parameters, supplemented by an MP2 normal-mode analysis at one transition state, and statistical theoretical methods, we have computed thermal rate coefficients for the reactions, (1) H + HNCO --> NCO + H2 and (2) H + HNCO --> NH2 + CO. Over the entire temperature range considered, 300 K < T < 3300 K, reaction (2) is the dominant product channel. The theoretical predictions are in excellent agreement with the experimental results available for k2 and k-1, the rate coefficient for the reverse of reaction (1). Modified Arrhenius expressions are given for k1, k-1, and k2. In addition, we identify and discuss a weakness in utilizing a Hartree-Fock normal-mode analysis in the prediction of k2. The present result for k2 is much smaller than that used in the initial modeling of the RAPRENO(x) process. The implications of this are discussed. RP MILLER, JA (reprint author), SANDIA NATL LABS, COMBUST RES FACIL, LIVERMORE, CA 94551 USA. NR 11 TC 18 Z9 18 U1 1 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAY PY 1992 VL 24 IS 5 BP 421 EP 432 DI 10.1002/kin.550240503 PG 12 WC Chemistry, Physical SC Chemistry GA HN400 UT WOS:A1992HN40000002 ER PT J AU KLEMM, LH LU, JJ KLEMM, RA AF KLEMM, LH LU, JJ KLEMM, RA TI KINETICS OF SOLVOLYSIS OF 1-ACETYL-4-(1-ETHOXYCARBONYL-1-CYANO) METHYLENE-1,4-DIHYDROQUINOLINE IN UNDRIED DMSO-D6 - FORMATION OF ACETIC-ANHYDRIDE AS AN INTERMEDIATE SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article AB The kinetics of solvolysis of the title compound (QAc) in undried DMSO-d6 to give 4-(1-ethoxycarbonyl-1-cyano)methylquinoline (QH) and HOAc at ambient temperature were investigated by H-1 nmr spectrometry. With a limited excess of water the solvolysis follows a three-step process of QAc + H2O --> k1 QH + HOAc, QAc + HOAc k-2 reversible k2 QH + Ac2O, and Ac2O + H2O --> k3 2 HOAc, where k2 > k1 and k3 < k1. Addition of pyridine-d5 to the reaction mixture markedly catalyzes the overall solvolysis, while addition of CF3CO2D to the reaction mixture simplifies the kinetics to pseudo first-order in [QAc] with k = 4.3 x 10(-3) min-1. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP KLEMM, LH (reprint author), UNIV OREGON,DEPT CHEM,EUGENE,OR 97403, USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAY PY 1992 VL 24 IS 5 BP 447 EP 454 DI 10.1002/kin.550240505 PG 8 WC Chemistry, Physical SC Chemistry GA HN400 UT WOS:A1992HN40000004 ER PT J AU KLEMM, RA KLEMM, LH AF KLEMM, RA KLEMM, LH TI KINETICS OF A 2ND-ORDER REACTION INVOLVING 2 INTERMEDIATE 2ND-ORDER REACTIONS SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article AB We have studied the kinetics of a reaction in which starting materials A and B react to form the products C and D directly, as well as by way of two additional intermediate reactions. In the first intermediate reaction, A and C react to form D and E, and in the second intermediate reaction, B and E react to form 2C. There are three conservation laws, which effectively reduce the number of variables to two, resulting in nonlinear coupled first order differential equations for [A](t) and [B](t). These equations are readily solved by standard numerical procedures, for various values of the relative reaction rates and starting concentrations. Our results are used to fit experimental data for the case in which A and B are 1-acetyl-4-(1-ethoxycarbonyl-1-cyano)methylene-1,4-dihydroquinoline and water, for which the first and third reverse reactions can be neglected. C1 UNIV OREGON,DEPT CHEM,EUGENE,OR 97403. RP KLEMM, RA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAY PY 1992 VL 24 IS 5 BP 455 EP 466 DI 10.1002/kin.550240506 PG 12 WC Chemistry, Physical SC Chemistry GA HN400 UT WOS:A1992HN40000005 ER PT J AU LIN, MC HE, YS MELIUS, CF AF LIN, MC HE, YS MELIUS, CF TI THEORETICAL INTERPRETATION OF THE KINETICS AND MECHANISMS OF THE HNO + HNO AND HNO + 2NO REACTIONS WITH A UNIFIED MODEL SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID GAS-PHASE PYROLYSIS; ALKYL NITRITES; TEMPERATURE AB Previously measured decay rates of HNO in the presence of NO have been kinetically modeled on the basis of thermochemical data calculated with the BAC-MP4 technique. The results of this modeling, aided by TST-RRKM calculations for the association of HNO and the isomerization, decomposition, and stabilization of the many dimers of HNO, reveal that the decay of HNO under NO-lean conditions occurs primarily by association forming cis- and trans-(HNO)2 at temperatures below 420 K. N2O, which is a relatively minor product, is believed to be formed by H2O elimination from cis-HON = NOH, a product of successive isomerization reactions: trans-(HNO)2 dagger --> HN(OH)NO dagger --> HN(O)NOH dagger --> cis-HON NOH dagger. The calculated rate constants, which fit experimental data quantitatively, can be represented by k = 10(16.2) x T-2.40e-590/T cm3/mol sec for the HNO recombination reaction and k = 10(-2.44)T3.98e-600)/T cm3/mol sec for N2O formation in the temperature range 80-420 K, at a total pressure of 710 torr H2 or He. Under NO-rich conditions, HNO reacts predominantly by the exothermic termolecular reaction, HNO + 2NO --> HN(NO)ONO --> HNNO + NO2, with a rate content of (16 +/- 1) x 10(9) cm6/mol2 sec at room temperature, based on both HNO decay and NO2 production. All existing thermal kinetic data on HNO + HNO and HNO + 2NO processes can be satisfactorily rationalized with a unified model based on the thermochemical data obtained by BAC-MP4 calculations. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94550. RP LIN, MC (reprint author), EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322, USA. NR 37 TC 43 Z9 43 U1 1 U2 5 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAY PY 1992 VL 24 IS 5 BP 489 EP 516 DI 10.1002/kin.550240509 PG 28 WC Chemistry, Physical SC Chemistry GA HN400 UT WOS:A1992HN40000008 ER PT J AU LAGE, JL BEJAN, A ANDERSON, R AF LAGE, JL BEJAN, A ANDERSON, R TI REMOVAL OF CONTAMINANT GENERATED BY A DISCRETE SOURCE IN A SLOT VENTILATED ENCLOSURE SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID MODEL AB This paper reports the results of a numerical study of the time-dependent removal of contaminant from a two-dimensional enclosure with one inlet and one outlet. The contaminant is generated beginning with the time t = 0 by a concentrated source located inside the enclosure. The contaminant is removed by the through flow established between the inlet and outlet ports. The flows studied cover the laminar and turbulent regimes represented by 30 less-than-or-equal-to Re less-than-or-equal-to 3000, where Re is the Reynolds number based on the inlet width and mean velocity. The effectiveness of the contaminant removal scheme is documented in terms of the removal efficiency eta(r), the volume-averaged concentration of contaminant CBAR, and the critical (clean up) time t(c). The effects of Re, ventilation jet orientation and source location are reported. It is shown that the movement and distribution of contaminant is complex and depends strongly on the source location. It is also shown how the relative positioning of the ports and the source location influence the contaminant removal process. The optimal inlet/outlet configuration associated with each position of the concentrated source of contaminant is reported. Slower ventilation schemes can lead to lower contaminant levels when a short contaminant removal time is not a major requirement. C1 SOLAR ENERGY RES INST,BLDG ENERGY TECHNOL PROGRAM,GOLDEN,CO 80401. RP LAGE, JL (reprint author), DUKE UNIV,DEPT MECH ENGN & MAT SCI,DURHAM,NC 27706, USA. RI Bejan, Adrian/D-3909-2012 NR 9 TC 22 Z9 22 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD MAY PY 1992 VL 35 IS 5 BP 1169 EP 1180 DI 10.1016/0017-9310(92)90177-T PG 12 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA HZ425 UT WOS:A1992HZ42500018 ER PT J AU FENG, WW HUNG, TK CHANG, GL AF FENG, WW HUNG, TK CHANG, GL TI EXTENSION AND TORSION OF HYPERVISCOELASTIC CYLINDERS SO INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS LA English DT Article AB The solution for finite deformations of a solid viscoelastic cylinder subjected to extension and torsion is presented. An experiment is performed on a latex rubber cylinder. Both axial load and torque histories of the deformed cylinder are recorded. The theoretical coupling relationship between torsion and extension is verified. With the theoretical and experimental results, the viscoelastic properties of the cylinder can be obtained. C1 UNIV PITTSBURGH,DEPT OBSTET GYNECOL,PITTSBURGH,PA 15261. UNIV PITTSBURGH,DEPT CIVIL ENGN,PITTSBURGH,PA 15261. NATL CHENG KUNG UNIV,INST BIOMED ENGN,TAINAN 70101,TAIWAN. RP FENG, WW (reprint author), LAWRENCE LIVERMORE NATL LAB,LAWRENCE LIVERMORE NATL LAB L-342,LIVERMORE,CA 94550, USA. NR 3 TC 3 Z9 4 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7462 J9 INT J NONLINEAR MECH JI Int. J. Non-Linear Mech. PD MAY PY 1992 VL 27 IS 3 BP 329 EP 335 DI 10.1016/0020-7462(92)90001-N PG 7 WC Mechanics SC Mechanics GA HW242 UT WOS:A1992HW24200001 ER PT J AU CARNES, BA GRDINA, DJ AF CARNES, BA GRDINA, DJ TI INVIVO PROTECTION BY THE AMINOTHIOL WR-2721 AGAINST NEUTRON-INDUCED CARCINOGENESIS SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID WHOLE-BODY EXPOSURE; CO-60 GAMMA-RAYS; FISSION NEUTRONS; CHEMICAL PROTECTION; IONIZING-RADIATION; ESCHERICHIA-COLI; GENETIC INJURY; V79 CELLS; MICE; SINGLE AB The ability of the compound S-2-(aminopropylamino)ethylphosphorothioic acid, designated WR-2721, to protect against neutron-induced carcinogenesis was investigated. Both sexes of the B6CF1 mouse were injected i.p. with 400 mg/kg of WR-2721 30 min prior to being irradiated by 10 cGy of neutrons. Neoplastic mortality in the groups receiving thiol was either reduced or delayed relative to irradiated mice not given protector. However, the time at which the protective effect of WR-2721 was expressed depended on the sex of the animal. Thiol-related shifts in the time of neoplastic death in females occurred only in the first half of the lifespan. Once a female survived to the mean age at death, no difference in the pattern of mortality could be detected between control and WR-2721-treated mice exposed to neutrons. Irrespective of thiol treatment, the timing of tumour-related death was nearly identical during the first half of life for males exposed to neutrons. In the last half of the lifespan, survival of thiol-protected males was enhanced relative to saline-injected males and even exceeded that observed in the control population. C1 UNIV CHICAGO,MED CTR,DEPT RADIAT & CELLULAR ONCOL,CHICAGO,IL 60637. RP CARNES, BA (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 37 TC 24 Z9 25 U1 2 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD MAY PY 1992 VL 61 IS 5 BP 567 EP 576 DI 10.1080/09553009214551381 PG 10 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA HU522 UT WOS:A1992HU52200002 PM 1349621 ER PT J AU COOK, NGW AF COOK, NGW TI NATURAL JOINTS IN ROCK - MECHANICAL, HYDRAULIC AND SEISMIC BEHAVIOR AND PROPERTIES UNDER NORMAL STRESS SO INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES & GEOMECHANICS ABSTRACTS LA English DT Article ID SATURATED ROCKS; FLUID-FLOW; FRACTURE; ATTENUATION; SURFACES; DISPERSION; WAVE; DEFORMATION; FREQUENCIES; ROUGHNESS AB The mechanical and hydraulic properties of many rock masses are affected significantly by the additional mechanical compliance and fluid conductivity that result from joints, fractures or faults. The effects of these features, generally referred to as joints, can be so pronounced in many problems in geology or geophysics, mining or petroleum engineering, hydrogeology and waste management that it is important to be able to locate and characterize them remotely within a rock mass using geophysical methods. The effect of joints on seismic wave propagation, therefore, becomes important also. Experimental measurements of the deformation of natural joints are analyzed in terms of theories concerning the roughness of the two joint surfaces and their deformation under stress. For many rocks, the deformation of the surfaces is reversible after the first few cycles of loading and unloading and is, therefore, elastic. The highly non-linear stress-deformation curves for joints must be a result of changes in the geometry of the areas of contact between asperities brought about by the elastic deformation of adjacent voids in response to changes in the applied stress. The flow of fluids between the surfaces of a joint must also depend upon the geometry of the void space between these surfaces. Measurements using liquid metal porosimetry, show that when the two surfaces of a natural joint are in contact with one another, this geometry becomes so complex that fluid through the joint cannot be approximated as laminar flow between parallel surfaces leading to a cubic relation between flux and aperture. At low stresses, fluid flow through a joint decreases much faster than the cube of the joint closure. This is shown to be a result of changes in contact area, tortuosity and hydraulic aperture brought about by deformation of the void space between the two surfaces of the joint. At high stresses, fluid flow through a joint asymptotes to an irreducible level, largely independent of joint closure and further changes in stress. The slope of a tangent to the curve relating the average closure between the two surfaces of a joint to the stress across the joint defines a specific stiffness for the joint at that stress. The effect of joints on seismic waves can be analyzed by using this specific stiffness as a boundary condition in the seismic wave equation. Displacements across this boundary are discontinuous while stresses are continuous. Although the specific stiffness of the joint and the properties of the rock on each side of it are assumed to be completely elastic, the displacement discontinuity leads to frequently-dependent reflection and transmission coefficients for compressional and shear waves as well as frequency-dependent group time delay for the transmitted waves. This concept can be extended to include a velocity discontinuity across the joint, where the contained fluid or the properties of the rock provide viscous as well as elastic coupling across a joint. Theoretical predictions based on the displacement discontinuity and velocity discontinuity theories agree very well with the results of laboratory measurements of seismic pulses transmitted across natural joints with different specific stiffnesses. C1 LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP COOK, NGW (reprint author), LAWRENCE BERKELEY LAB,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 54 TC 183 Z9 200 U1 7 U2 48 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0148-9062 J9 INT J ROCK MECH MIN JI Int. J. Rock Mech. Min. Sci. PD MAY PY 1992 VL 29 IS 3 BP 198 EP 223 DI 10.1016/0148-9062(92)93656-5 PG 26 WC Engineering, Geological; Mining & Mineral Processing SC Engineering; Mining & Mineral Processing GA HZ066 UT WOS:A1992HZ06600002 ER PT J AU HIXSON, RS WINKLER, MA AF HIXSON, RS WINKLER, MA TI THERMOPHYSICAL PROPERTIES OF MOLYBDENUM AND RHENIUM SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE DENSITY; ELECTRICAL RESISTIVITY; ENTHALPY; MOLYBDENUM; PULSE HEATING TECHNIQUE; RHENIUM; SOUND VELOCITY ID LIQUID AB Thermophysical properties measurements have been made on the metals molybdenum and rhenium at high temperatures and a pressure of 0.2 GPa. These measured properties include volume, temperature. enthalpy, and electrical resistivity. Values for these quantities are shown for both solid and liquid phases. In addition, sound velocities were measured for liquid molybdenum. RP HIXSON, RS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 13 TC 22 Z9 22 U1 1 U2 9 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1992 VL 13 IS 3 BP 477 EP 487 DI 10.1007/BF00503884 PG 11 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA HQ424 UT WOS:A1992HQ42400007 ER PT J AU GATHERS, GR AF GATHERS, GR TI ANALYSIS OF MULTIWAVELENGTH PYROMETRY USING NONLINEAR CHI-SQUARE FITS AND MONTE-CARLO METHODS SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE HIGH TEMPERATURE; MONTE CARLO; PYROMETRY; RADIATION THERMOMETRY ID SHOCK-TEMPERATURE-MEASUREMENTS; COMPRESSED WATER AB An analysis of multiwavelength pyrometry is made using Monte Carlo methods to evaluate the measurement error as a function of temperature for three, four, five, and six channels. Both a graybody and an emissivity with linear wavelength dependence are considered. Chi-2 is calculated using the observed intensity in each channel and is minimized with respect to the temperature and the emissivity coefficients, using the Levenberg Marquardt method. The influence of spectral span of the channels and the weight function used in the chi-2 fit are examined. For the case of linear wavelength dependence, the solutions are found to be nonunique, even with six channels. The results show little improvement of precision with increasing number of channels beyond four channels when the nonlinear variable T is free. Both the spectral span and the weight function are shown to be important variables. RP GATHERS, GR (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 15 TC 26 Z9 27 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1992 VL 13 IS 3 BP 539 EP 554 DI 10.1007/BF00503888 PG 16 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA HQ424 UT WOS:A1992HQ42400011 ER PT J AU EADES, JF AF EADES, JF TI A NOTE ON THE PERSISTENCE OF THE HERBICIDE DICHLOBENIL IN GROUNDWATER SO IRISH JOURNAL OF AGRICULTURAL AND FOOD RESEARCH LA English DT Article DE DICHLOBENIL; GROUNDWATER; HERBICIDE PERSISTENCE AB Dichlobenil was detected in the groundwater under an industrial site more than three years after the site had been treated with the herbicide. RP EADES, JF (reprint author), TEAGASC,OAK PK RES CTR,CARLOW,IRELAND. NR 0 TC 2 Z9 2 U1 0 U2 0 PU TEAGASC PI DUBLIN PA 19 SANDYMOUNT AVE, DUBLIN 4, IRELAND SN 0791-6833 J9 IRISH J AGR FOOD RES JI Irish J. Agr. Food Res. PD MAY PY 1992 VL 31 IS 1 BP 81 EP 83 PG 3 WC Agriculture, Multidisciplinary; Food Science & Technology SC Agriculture; Food Science & Technology GA JE752 UT WOS:A1992JE75200009 ER PT J AU FUNG, KH TANG, IN AF FUNG, KH TANG, IN TI AEROSOL-PARTICLE ANALYSIS BY RESONANCE RAMAN-SPECTROSCOPY SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID MORPHOLOGY-DEPENDENT RESONANCES; SOLUTION DROPLETS; SCATTERING; WATER; SIZE AB In this report, resonance Raman spectroscopy is used for the first time to enhance the low Raman scattering signal from suspended particles. Sodium nitrate is used as an internal standard for this study. The enhancement factor is measured to be 20 for sodium chromate in the pre-resonance scheme and 300 for the permanganate ion in the resonance conditions. The results have demonstrated the feasibility of applying resonance Raman spectroscopy to the chemical analysis of aerosol particles. RP FUNG, KH (reprint author), BROOKHAVEN NATL LAB, DEPT APPL SCI, DIV ENVIRONM CHEM, UPTON, NY 11973 USA. NR 21 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD MAY PY 1992 VL 23 IS 3 BP 301 EP 307 DI 10.1016/0021-8502(92)90330-X PG 7 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA HW834 UT WOS:A1992HW83400008 ER PT J AU HUYER, SA ROBINSON, MC LUTTGES, MW AF HUYER, SA ROBINSON, MC LUTTGES, MW TI UNSTEADY AERODYNAMIC LOADING PRODUCED BY A SINUSOIDALLY OSCILLATING DELTA WING SO JOURNAL OF AIRCRAFT LA English DT Article AB The unsteady aerodynamic loading produced by an oscillating delta wing was examined for a range of reduced frequencies and mean angles of attack. A three degree of freedom force balance recorded normal and tangential force data. These data were then reduced to provide unsteady lift and drag force coefficient values. The resultant aerodynamic loads were highly transient in nature and lift enhancement up to twice that of steady-state values was achieved for limiting test cases. The delta wing also experienced lift reduction during portions of the pitching cycle. Reduced dynamic drag was seen for instantaneous wing angles of attack below static stall. Hysteresis loops demonstrated the unsteadiness of the resultant flowfields and were seen for all test cases. Force balance measurements supported hypotheses on both unsteady separation mechanisms and dynamics for a delta wing. Unsteady lift integrations over time highlighted relations between reduced frequency and mean angle of attack for total bounded vorticity throughout the pitching cycle. RP HUYER, SA (reprint author), NATL RENEWABLE ENERGY LABS,GOLDEN,CO, USA. NR 0 TC 3 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1992 VL 29 IS 3 BP 366 EP 373 DI 10.2514/3.46171 PG 8 WC Engineering, Aerospace SC Engineering GA HX252 UT WOS:A1992HX25200013 ER PT J AU HALBROOK, RS GUZMAN, CE WILKINSON, KJ WATSON, AP MUNRO, NB SHUGART, LR AF HALBROOK, RS GUZMAN, CE WILKINSON, KJ WATSON, AP MUNRO, NB SHUGART, LR TI RAPID WHOLE-BLOOD CHOLINESTERASE ASSAY WITH POTENTIAL USE FOR BIOLOGICAL MONITORING DURING CHEMICAL WEAPONS DISPOSAL SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article AB A protocol is described to determine whole-blood cholinesterase activity using an automated high-speed centrifugal analyzer. Throughput rate was increased 10-fold (from 6 to 60 samples/h), and precision, as measured by a reduction in intra-aliquot variation, was significantly improved (from 4.7 to 3.0%) by using an automated system rather than a manual system. Similar cholinesterase activity was determined for samples analyzed by both the automated and manual protocols, and interlaboratory comparison Indicated no change in accuracy. The lower limit of detection was estimated to be 0.10-mu-mol/mL/min. The 10-fold increase in through-put facilitates use of the automated protocol when many analyses must be performed in a limited time. C1 OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831. RP HALBROOK, RS (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD MAY-JUN PY 1992 VL 75 IS 3 BP 549 EP 553 PG 5 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA HW428 UT WOS:A1992HW42800022 ER PT J AU FARTASH, A SCHULLER, IK GRIMSDITCH, M AF FARTASH, A SCHULLER, IK GRIMSDITCH, M TI THIN-FILM MODELING FOR MECHANICAL MEASUREMENTS - SHOULD MEMBRANES BE USED OR PLATES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTERNAL-FRICTION; ELASTIC-MODULUS; FOILS AB The two limits for modeling vibrating thin films, viz as a plate or as a membrane, are discussed. In terms of these limits the sources of experimental uncertanties are identified and the advantages of using films which can be modeled as membranes are explained. The mathematical formalism for treating films as vibrating membranes is developed and relations for self-consistency checks are presented. The drive mechanisms used to generate vibrations in the films are also discussed. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP FARTASH, A (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS 0319,LA JOLLA,CA 92093, USA. NR 15 TC 9 Z9 9 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1992 VL 71 IS 9 BP 4244 EP 4248 DI 10.1063/1.350804 PG 5 WC Physics, Applied SC Physics GA HR455 UT WOS:A1992HR45500021 ER PT J AU STEARNS, DG AF STEARNS, DG TI X-RAY-SCATTERING FROM INTERFACIAL ROUGHNESS IN MULTILAYER STRUCTURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LIGHT-SCATTERING; SURFACES; GROWTH; FILMS AB A quantitative theory of the nonspecular scattering of x rays from multilayer structures having rough interfaces is presented. The results are valid for arbitrary polarization and angles of incidence (measured from the normal) less than the critical angle for total external reflection. A structural model is adopted wherein each interface is assumed to be described by a surface having statistically random roughness with a well-behaved power spectrum. In addition, the model accounts for arbitrary correlation of the roughness between different interfaces. Calculations are presented for a variety of roughness configurations to investigate the dependence of the nonspecular scattering on the fundamental structural parameters. In particular, it is shown that the scattering from correlated roughness exhibits characteristic resonance behavior (quasi-Bragg diffraction). RP STEARNS, DG (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 38 TC 135 Z9 139 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1992 VL 71 IS 9 BP 4286 EP 4298 DI 10.1063/1.350810 PG 13 WC Physics, Applied SC Physics GA HR455 UT WOS:A1992HR45500027 ER PT J AU LI, Z FOSTER, CM DAI, XH XU, XZ CHAN, SK LAM, DJ AF LI, Z FOSTER, CM DAI, XH XU, XZ CHAN, SK LAM, DJ TI PIEZOELECTRICALLY-INDUCED SWITCHING OF 90-DEGREES DOMAINS IN TETRAGONAL BATIO3 AND PBTIO3 INVESTIGATED BY MICRO-RAMAN SPECTROSCOPY SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ZONE-CENTER PHONONS; PRESSURE; MODES AB Domain switching of 90-degrees ferroelectric domains in tetragonal BaTiO3 and PbTiO3 is induced by the application of stress along specific crystallographic axes. For BaTiO3, single-domain crystals are obtained from twinned specimens by the application of approximately 1.1 MPa of stress parallel to the a axis and twin boundaries are induced by application of approximately 0.22 MPa of stress parallel to the c axis. Similar piezoelectrically-induced domain switching was observed in PbTiO3 at elevated temperature. We observed the rotation of the crystallographic axes associated with domain switching via micro-Raman spectroscopy. These results were consistent with optical microscope images of the domain switching which demonstrates the usefulness of micro-Raman spectroscopy for the study of ferroelectric domain structures. A phenomenological treatment of domain switching in a piezoelectrically-coupled system is described. RP LI, Z (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 24 TC 62 Z9 62 U1 2 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1992 VL 71 IS 9 BP 4481 EP 4486 DI 10.1063/1.350792 PG 6 WC Physics, Applied SC Physics GA HR455 UT WOS:A1992HR45500058 ER PT J AU SETLOW, JK RANDESI, M ADAMS, JG SETLOW, B SETLOW, P AF SETLOW, JK RANDESI, M ADAMS, JG SETLOW, B SETLOW, P TI MUTATION AND KILLING OF ESCHERICHIA-COLI EXPRESSING A CLONED BACILLUS-SUBTILIS GENE WHOSE PRODUCT ALTERS DNA CONFORMATION SO JOURNAL OF BACTERIOLOGY LA English DT Article ID ULTRAVIOLET-LIGHT; UV MUTAGENESIS; RECA PROTEIN; INDUCTION; DEFICIENT; MUTANTS; SYSTEM; REPAIR AB Expression of the Bacillus subtilis gene coding for SspC, a small, acid-soluble protein, caused both killing and mutation in a number of Escherichia coli B and K-12 strains. SspC was previously shown to bind E. coli DNA in vivo, and in vitro this protein binds DNA and converts it into an A-like conformation. Analysis of revertants of nonsense mutations showed that SspC caused single-base changes, and a greater proportion of these were at A-T base pairs. Mutation in the recA gene abolished the induction of mutations upon synthesis of SspC, but the killing was only slightly greater than in RecA+ cells. Mutations in the umuC and umuD genes eliminated most of the mutagenic effect of SspC but not the killing, while the lexA mutation increased mutagenesis but did not appreciably affect the killing. Since there was neither killing nor mutation of E. coli after synthesis of a mutant SspC which does not bind DNA, it appears likely that the binding of wild-type SspC to DNA, with the attendant conformational change, was responsible for the killing and mutation. A strain containing the B. subtilis gene that is constitutive for the RecA protein at 42-degrees-C showed a lower frequency of mutation when that temperature was used to induce the RecA protein than when the temperature was 30-degrees-C, where the RecA level is low, suggesting that at the elevated temperature the high RecA level could be inhibiting binding of the B. subtilis protein to DNA. C1 UNIV CONNECTICUT,CTR HLTH,DEPT BIOCHEM,FARMINGTON,CT 06032. RP SETLOW, JK (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. FU NIGMS NIH HHS [GM-19698] NR 35 TC 9 Z9 10 U1 1 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD MAY PY 1992 VL 174 IS 9 BP 2943 EP 2950 PG 8 WC Microbiology SC Microbiology GA HR231 UT WOS:A1992HR23100027 PM 1314805 ER PT J AU WU, X GERSTEIN, BC KING, TS AF WU, X GERSTEIN, BC KING, TS TI THE EFFECT OF CHLORINE ON HYDROGEN CHEMISORPTION BY SILICA-SUPPORTED RU CATALYSTS - A PROTON NMR-STUDY SO JOURNAL OF CATALYSIS LA English DT Article ID SURFACE-AREA MEASUREMENTS; ACTIVATED CHEMISORPTION; REDUCTION TEMPERATURE; RUTHENIUM CATALYSTS; ADSORBED CHLORINE; RESONANCE; CO; PROMOTION; RU/AL2O3; RU/SIO2 C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP WU, X (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM ENGN,231 SWEENEY HALL,AMES,IA 50011, USA. NR 21 TC 28 Z9 29 U1 2 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY PY 1992 VL 135 IS 1 BP 68 EP 80 DI 10.1016/0021-9517(92)90269-N PG 13 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA HP047 UT WOS:A1992HP04700006 ER PT J AU ZHANG, R SCHWARZ, JA DATYE, A BALTRUS, JP AF ZHANG, R SCHWARZ, JA DATYE, A BALTRUS, JP TI THE EFFECT OF 2ND-PHASE OXIDES ON THE CATALYTIC PROPERTIES OF DISPERSED METALS - COBALT SUPPORTED ON 12-PERCENT WO3/AL2O3 SO JOURNAL OF CATALYSIS LA English DT Article ID TEMPERATURE-PROGRAMMED REDUCTION; RAY PHOTOELECTRON-SPECTROSCOPY; ENHANCED METHANATION ACTIVITY; TUNGSTEN-ALUMINA CATALYSTS; CO HYDROGENATION; RUTHENIUM CATALYSTS; NI/AL2O3 CATALYSTS; PARTICLE-SIZE; SURFACE; HYDRODESULFURIZATION C1 SYRACUSE UNIV,DEPT CHEM ENGN & MAT SCI,SYRACUSE,NY 13244. UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. US DOE,PITTSBURGH ENERGY TECHNOL CTR,PITTSBURGH,PA 15236. NR 37 TC 20 Z9 21 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY PY 1992 VL 135 IS 1 BP 200 EP 222 DI 10.1016/0021-9517(92)90280-U PG 23 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA HP047 UT WOS:A1992HP04700017 ER PT J AU OLINS, AL OLINS, DE BAZETTJONES, DP AF OLINS, AL OLINS, DE BAZETTJONES, DP TI BALBIANI RING HNRNP SUBSTRUCTURE VISUALIZED BY SELECTIVE STAINING AND ELECTRON SPECTROSCOPIC IMAGING SO JOURNAL OF CELL BIOLOGY LA English DT Article ID SALIVARY-GLAND CELLS; MICROSCOPE TOMOGRAPHY; RIBONUCLEOPROTEIN-PARTICLES; CHIRONOMUS-TENTANS; MESSENGER-RNA; DNA; TRANSCRIPTION; LOCALIZATION; SECTIONS; TRANSPORT AB The Balbiani Rings (BR) in the polytene chromosomes of Chironomus salivary glands are intense sites of transcription. The nascent RNPs fold during transcription into 40-50-nm granules, containing in the mature transcript approximately 37-kb RNA. Using a new nucleic acid specific stain, osmium ammine B on Lowicryl sections, in combination with electron energy filtered imaging of sections containing BR granules, we demonstrate a RNA-rich particulate substructure (10-nm particle diameter; 10-12 particles per BR granule). Elemental imaging supports that these particles are enriched in phosphorus. The possible relationship of these RNA-rich particles to ribonucleosomes is discussed, as well as models for their arrangement in the mature BR granules. C1 UNIV CALGARY,DEPT MED BIOCHEM,CALGARY T2N 4N1,ALBERTA,CANADA. RP OLINS, AL (reprint author), UNIV TENNESSEE,OAK RIDGE GRAD SCH BIOMED SCI,DIV BIOL,OAK RIDGE,TN 37831, USA. NR 38 TC 20 Z9 20 U1 0 U2 1 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD MAY PY 1992 VL 117 IS 3 BP 483 EP 491 DI 10.1083/jcb.117.3.483 PG 9 WC Cell Biology SC Cell Biology GA HR017 UT WOS:A1992HR01700002 PM 1374066 ER PT J AU BRAUNSTEIN, M PACK, RT AF BRAUNSTEIN, M PACK, RT TI SIMPLE THEORY OF DIFFUSE STRUCTURE IN CONTINUOUS ULTRAVIOLET-SPECTRA OF POLYATOMIC-MOLECULES .3. APPLICATION TO THE WULF-CHAPPUIS BAND SYSTEM OF OZONE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACES; EXCITED-STATES; PHOTO-DISSOCIATION; CONFIGURATION INTERACTION; TRIATOMIC-MOLECULES; ABSORPTION-SPECTRA; PHOTODISSOCIATION; DYNAMICS; O-3 AB We apply a simple model for the photodissociation absorption spectra of bent symmetric triatomic molecules to the Wulf-Chappuis band system of ozone (10 000-22 000 cm-1) to assign the electronic states and the diffuse vibrational bands involved. The conical intersection between the two lowest 1A" states is treated in an approximate way, and the role of the lowest excited triplet states is explored. The results indicate that the Wulf band is probably due to the 3A2 state of ozone which gains intensity through spin-orbit coupling. The 1 1A" (1A2) state gives rise to the featureless red wing of the Chappuis band. Most of the structure in the Chappuis band is reproduced in the model and is due to the 2 1A" (1B1) state as was previously supposed. A more complete treatment of the conical intersection and nonadiabatic effects will be necessary to quantitatively reproduce all features of the experimental spectra. RP UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET, T-12 MSB268, LOS ALAMOS, NM 87545 USA. NR 29 TC 57 Z9 58 U1 1 U2 2 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 MAY 1 PY 1992 VL 96 IS 9 BP 6378 EP 6388 DI 10.1063/1.462632 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700006 ER PT J AU GRAY, SK AF GRAY, SK TI WAVE PACKET DYNAMICS OF RESONANCE DECAY - AN ITERATIVE EQUATION APPROACH WITH APPLICATION TO HCO-]H+CO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; WAVEPACKET CALCULATIONS; MOLECULAR-DYNAMICS; QUANTUM SCATTERING; PROPAGATION; SURFACES AB Three-dimensional solutions to the time-dependent Schrodinger equation, corresponding to the decay of resonances in the HCO radical, are studied. Theoretical tools to facilitate such studies are discussed. A novel propagation scheme, based on iterative equation equivalents to the Schrodinger equation, is developed. The HCO calculations are performed by representing the wave function with a grid and basis set expansion, and by using a Lanczos procedure to evaluate operator actions. Resonance energies and decay widths are obtained by analyzing correlation functions over relatively short time periods with Prony's method of spectral analysis. Product distributions are also estimated, and results are compared with previous time-independent scattering results. Inspection of the time-evolving probability density yields a picture of the decay mechanism, and points to the origins of structure in the product distributions. RP GRAY, SK (reprint author), ARGONNE NATL LAB,DIV CHEM,THEORET CHEM GRP,ARGONNE,IL 60439, USA. NR 39 TC 148 Z9 148 U1 2 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6543 EP 6554 DI 10.1063/1.462593 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700023 ER PT J AU YOO, RK RUSCIC, B BERKOWITZ, J AF YOO, RK RUSCIC, B BERKOWITZ, J TI PHOTOIONIZATION OF AS2 AND AS4 - IMPLICATIONS FOR GROUP-V CLUSTERS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TEMPERATURE NEGATIVE-IONS; PHOTOELECTRON-SPECTROSCOPY; ELECTRONIC-STRUCTURE; ANTIMONY; TETRAMERS; ELEMENTS; IMPACT; MOLECULES; AS-4(+); SB-4(+) AB The vacuum ultraviolet photoionization mass spectrum of As4 is presented, from the ionization threshold to 600 angstrom. The apparent adiabatic ionization potential is less-than-or-equal-to 8.49 eV, but the true value may be significantly lower. Three broad autoionization features are observed, probably comprising members of a Rydberg series converging to the B approximately 2A1 state of As4+. The first fragment, As3+, has an appearance potential (0 K) of 11.23 +/- 0.05 eV, from which we extract DELTA-H(fo)o (As3+) less-than-or-equal-to 228.7 +/- 1.3 kcal/mol. The photoion yield curve of As2+ (As2) is obtained under conditions where As2 is dominant in the vapor. The adiabatic ionization potential is 9.69 +/- 0.02 eV. Two prominent autoionizing Rydberg series are observed, converging to the A (2)SIGMA(g)+ state of As2+, with an ionization potential of 10.238 +/- 0.002 eV. At higher energy, three members of a window resonance series can be seen, converging to the B (2)SIGMA(u)+ state of As2+, with an ionization potential of 15.37 eV. From an upper limit to the partial pressure of As3, equilibrium conditions, and assuming a triangular As3, we deduce DELTA-H(fo)o (As3) greater-than-or-equal-to 60.0 kcal/mol; other criteria suggest DELTA-H(fo)o (As3) congruent-to 63 kcal/mol. Consequently, the adiabatic ionization potential of As3 is < 7.32 eV, and probably less-than-or-equal-to 7.19 eV. Several implications are drawn, relevant to recent studies of antimony and bismuth clusters. RP YOO, RK (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Ruscic, Branko/A-8716-2008 OI Ruscic, Branko/0000-0002-4372-6990 NR 55 TC 29 Z9 31 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6696 EP 6709 DI 10.1063/1.462579 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700038 ER PT J AU DAVIS, HF SUITS, AG LEE, YT AF DAVIS, HF SUITS, AG LEE, YT TI REACTIONS OF BARIUM ATOMS WITH TRIATOMIC OXIDANTS .1. BA+NO2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID STATE; BAO; NO2; CHEMILUMINESCENCE; FLUORESCENCE; SPECTRUM; KINETICS; DYNAMICS; OXIDES; ALKALI AB Angular and velocity distributions of the neutral products resulting from the reaction Ba + NO2 were measured using the crossed molecular beams method. Despite a large reaction exoergicity (DELTA-H = -61 kcal/mol), formation of the dominant ground state BaO((1)SIGMA) + NO products results primarily from decay of long-lived Ba+NO2- collision complexes, even at incident collision energies as high as 59 kcal/mol or with electronic excitation of the Ba atom. A large fraction of the reaction exoergicity is channeled into product translational energy. This rather unusual behavior results from a large exit potential-energy barrier for decay of the initially formed singly ionic Ba+NO2- intermediate to ground state doubly ionic Ba2+O2-. A secondary source of forward scattered, internally excited BaO results from a direct reaction without the involvement of long-lived intermediates. An additional minor channel, formation of BaNO + O is observed from ground state Ba + NO2 at high collision energies by a direct reaction mechanism. Unlike the dominant BaO + NO channel, which involves harpooning at the first ionic-covalent curve crossing, formation of BaNO from reaction of ground state Ba likely results from the small range of collision geometries which are able to avoid long range electron transfer. The BaNO + O channel was enhanced substantially by electronic excitation of the incident barium atom. However, BaNO from reactions of electronically excited Ba primarily resulted from decay of collision complexes, rather than from a direct mechanism. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP DAVIS, HF (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720, USA. RI Lee, Yuan-Tseh/F-7914-2012 NR 87 TC 12 Z9 12 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6710 EP 6726 DI 10.1063/1.462580 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700039 ER PT J AU KENDALL, RA DUNNING, TH HARRISON, RJ AF KENDALL, RA DUNNING, TH HARRISON, RJ TI ELECTRON-AFFINITIES OF THE 1ST-ROW ATOMS REVISITED - SYSTEMATIC BASIS-SETS AND WAVE-FUNCTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION; NEGATIVE-IONS; BINDING-ENERGIES; OXYGEN; FLUORINE; HYDROGEN; CARBON AB The calculation of accurate electron affinities (EAs) of atomic or molecular species is one of the most challenging tasks in quantum chemistry. We describe a reliable procedure for calculating the electron affinity of an atom and present results for hydrogen, boron, carbon, oxygen, and fluorine (hydrogen is included for completeness). This procedure involves the use of the recently proposed correlation-consistent basis sets augmented with functions to describe the more diffuse character of the atomic anion coupled with a straightforward, uniform expansion of the reference space for multireference singles and doubles configuration-interaction (MRSD-CI) calculations. Comparison with previous results and with corresponding full CI calculations are given. The most accurate EAs obtained from the MRSD-CI calculations are (with experimental values in parentheses) hydrogen 0.740 eV (0.754), boron 0.258 (0.277), carbon 1.245 (1.263), oxygen 1.384 (1.461), and fluorine 3.337 (3.401). The EAs obtained from the MR-SDCI calculations differ by less than 0.03 eV from those predicted by the full CI calculations. C1 PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. ARGONNE NATL LAB, THEORET CHEM GRP, ARGONNE, IL 60439 USA. RP PACIFIC NW LAB, MOLEC SCI SOFTWARE GRP, RICHLAND, WA 99352 USA. RI Franco-Hurtado, Fernando/E-5599-2017 OI Franco-Hurtado, Fernando/0000-0001-5775-0150 NR 45 TC 8255 Z9 8278 U1 42 U2 337 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 MAY 1 PY 1992 VL 96 IS 9 BP 6796 EP 6806 DI 10.1063/1.462569 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700049 ER PT J AU MAZUMDAR, S GUO, D DIXIT, SN AF MAZUMDAR, S GUO, D DIXIT, SN TI HIGH-ENERGY 2-PHOTON STATES IN FINITE VERSUS INFINITE POLYENES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLYDIACETYLENE; SPECTRA; EXCITATIONS; ELECTROREFLECTANCE; EXCITONS; CRYSTALS AB Optical nonlinearity in pi-conjugated polyenes depends crucially on a single two-photon state that is located above the one-photon allowed exciton. In the case of the infinite polyene this single state should be thought of as a collection of states with very narrow bandwidth. The location of this two-photon state in the infinite polyene is of considerable interest. We present numerical data for finite chains and discuss in detail why extrapolation of finite chain data to obtain the energies of the high energy states in the infinite polyene requires considerable care. Based on upper and lower bounds that we put on the energy of the two-photon state in question, we predict it to be extremely close to the one-photon excition in the infinite chain limit. We present recent experimental data for a polydiacetylene that is consistent with our prediction. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550. RP MAZUMDAR, S (reprint author), UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721, USA. NR 27 TC 22 Z9 23 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6862 EP 6867 DI 10.1063/1.462576 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700056 ER PT J AU CURTISS, LA DEUTSCH, PW RAGHAVACHARI, K AF CURTISS, LA DEUTSCH, PW RAGHAVACHARI, K TI BINDING-ENERGIES AND ELECTRON-AFFINITIES OF SMALL SILICON CLUSTERS (N = 2-5) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-ENERGIES; GAUSSIAN-1 THEORY; GROUND-STATE; SI-3; MICROCLUSTERS; SI3 AB The Gaussian-2 (G2) theoretical procedure, based on ab initio molecular orbital theory, is used to calculate the energies of Si(n) and Si(n)- (n = 1-5) clusters. The G2 energies are used to derive accurate binding energies and electron affinities of these clusters. The calculated electron affinities of Si2-Si4 are in agreement to within 0.1 eV with results from recent photoelectron spectroscopic measurements. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. AT&T BELL LABS,MURRAY HILL,NJ 07974. PENN STATE UNIV,DEPT PHYS,MONACA,PA 15061. RP CURTISS, LA (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439, USA. NR 30 TC 65 Z9 65 U1 0 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6868 EP 6872 DI 10.1063/1.462577 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700057 ER PT J AU DANG, LX AF DANG, LX TI DEVELOPMENT OF NONADDITIVE INTERMOLECULAR POTENTIALS USING MOLECULAR-DYNAMICS - SOLVATION OF LI+ AND F- IONS IN POLARIZABLE WATER SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAS-PHASE; CL IONS; COMPLEXES; HYDRATION; ABINITIO; PAIR; NA+ AB Nonadditive intermolecular potentials for ion-H2O and ion-(H2O)2 complexes (ion = Li+ and F-) were derived using molecular-dynamics methods. The successive H2O binding energies and structural properties of Li+ (H2O)n and F-(H2O)n (n = 3-6) clusters, including simulations of aqueous ionic solutions, were examined using these potential parameters. The results reproduce well-observed solvation enthalpies as well as structural properties for these ions. For n < 5, water molecules distributed almost symmetrically around the Li+ ion, while water molecules preferred to cluster on the same side of the F- ion. These features are in agreement with earlier Monte Carlo, molecular dynamics, and molecular mechanics studies on similar systems. We studied the relationships between ionic clusters and bulk simulations by comparing structural properties for these simulations. In many cases, we found these properties were quite similar. These results provide valuable information in understanding the relationships between ionic clusters and solution chemistry. RP DANG, LX (reprint author), PACIFIC NW LAB, THEORY MODELING & SIMULAT MOLEC SCI RES CTR, POB 999, RICHLAND, WA 99352 USA. NR 33 TC 181 Z9 183 U1 3 U2 18 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 6970 EP 6977 DI 10.1063/1.462555 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700068 ER PT J AU SUMPTER, BG GETINO, C NOID, DW AF SUMPTER, BG GETINO, C NOID, DW TI COMPUTATIONAL STUDIES OF SUBMICRON PROBING OF POLYMER SURFACES .1. SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SCANNING TUNNELING MICROSCOPY; ATOMIC-FORCE-MICROSCOPE; MOLECULAR-DYNAMICS SIMULATIONS; COMPUTER-SIMULATION; CONFORMATIONAL DISORDER; GRAPHITE; TIP; POLYETHYLENE; IMAGES; MODEL AB The atomistic details of the interaction of an atomic force microscopic (AFM) probe with a polymer surface are examined by using the molecular-dynamics method. It is found that the perturbation of the AFM probe can produce a deformation of the local structure of the polymer surface. The dynamics study reveals how the structural changes evolve during the surface probing experiment, and whether the deformations result in permanent or reversible structural damage upon removing the probe. The effects of probe features (radius of curvature) and load force on the surface deformation(s) and image resolution are investigated in both a constant-force and constant-height AFM mode. Load forces between 10(-8) and 10(-11) N were determined to be an optimum working range for nondestructive AFM probing of polymer surfaces, and consequently for well-resolved surface image production. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. RP SUMPTER, BG (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 45 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 7072 EP 7085 DI 10.1063/1.462539 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700080 ER PT J AU ZHANG, BL WANG, CZ HO, KM AF ZHANG, BL WANG, CZ HO, KM TI SEARCH FOR THE GROUND-STATE STRUCTURE OF C84 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID STABILITY C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP ZHANG, BL (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 17 TC 73 Z9 73 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 7183 EP 7185 DI 10.1063/1.462532 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700096 ER PT J AU VRAKKING, MJJ BRACKER, AS LEE, YT AF VRAKKING, MJJ BRACKER, AS LEE, YT TI 2-PHOTON SPECTROSCOPY OF N2 - MULTIPHOTON IONIZATION, LASER-INDUCED FLUORESCENCE, AND DIRECT ABSORPTION VIA THE A'' 1-SIGMA-G+ STATE - COMMENT SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP VRAKKING, MJJ (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Lee, Yuan-Tseh/F-7914-2012 NR 11 TC 2 Z9 2 U1 2 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1992 VL 96 IS 9 BP 7195 EP 7196 DI 10.1063/1.462528 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR467 UT WOS:A1992HR46700102 ER PT J AU SMITHWICK, RW BOULET, JAM AF SMITHWICK, RW BOULET, JAM TI ELECTRICALLY DRIVEN OSCILLATIONS OF A MERCURY-DROPLET ELECTRODE SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article ID FLATTENED DROP; VIBRATION C1 UNIV TENNESSEE,DEPT ENGN SCI & MECH,KNOXVILLE,TN 37996. RP SMITHWICK, RW (reprint author), MARTIN MARIETTA ENERGY SYST INC,DEPT PLANT LAB,DIV QUAL SERV,OAK RIDGE Y-12 PLANT,BLDG 9995,OAK RIDGE,TN 37831, USA. NR 17 TC 6 Z9 6 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD MAY PY 1992 VL 150 IS 2 BP 567 EP 574 DI 10.1016/0021-9797(92)90225-B PG 8 WC Chemistry, Physical SC Chemistry GA HQ282 UT WOS:A1992HQ28200028 ER PT J AU KAMIMURA, T MONTALVO, E BARNES, DC LEBOEUF, JN TAJIMA, T AF KAMIMURA, T MONTALVO, E BARNES, DC LEBOEUF, JN TAJIMA, T TI IMPLICIT PARTICLE SIMULATION OF ELECTROMAGNETIC PLASMA PHENOMENA SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID TIME INTEGRATION C1 UNIV TEXAS,CTR FUS ENGN,AUSTIN,TX 78712. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712. RP KAMIMURA, T (reprint author), NATL INST FUS SCI,NAGOYA,JAPAN. NR 27 TC 6 Z9 6 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1992 VL 100 IS 1 BP 77 EP 90 DI 10.1016/0021-9991(92)90311-L PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA HV236 UT WOS:A1992HV23600007 ER PT J AU TALEZER, H KOSLOFF, R CERJAN, C AF TALEZER, H KOSLOFF, R CERJAN, C TI LOW-ORDER POLYNOMIAL-APPROXIMATION OF PROPAGATORS FOR THE TIME-DEPENDENT SCHRODINGER-EQUATION SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID DYNAMICS C1 DEPT PHYS CHEM,IL-91904 JERUSALEM,ISRAEL. FRITZ HABER INST,IL-91904 JERUSALEM,ISRAEL. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP TALEZER, H (reprint author), TEL AVIV UNIV,DEPT APPL MECH,IL-69978 TEL AVIV,ISRAEL. RI Kosloff, Ronnie/D-2388-2013 OI Kosloff, Ronnie/0000-0001-6201-2523 NR 17 TC 44 Z9 44 U1 2 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1992 VL 100 IS 1 BP 179 EP 187 DI 10.1016/0021-9991(92)90318-S PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA HV236 UT WOS:A1992HV23600014 ER PT J AU GARZON, FH RAISTRICK, ID BROWN, DR AF GARZON, FH RAISTRICK, ID BROWN, DR TI IMPROVED BARIUM FLUORIDE PROCESS YBA2CU3O7-X FILMS VIA POST-ANNEAL MONITORING SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 33RD ELECTRONIC MATERIALS CONF CY JUN, 1991 CL BOULDER, CO DE YBCO THIN FILMS; NDGAO3 SUBSTRATE; LAAIO3 SUBSTRATE; POST ANNEALING ID THIN-FILMS AB The continuous monitoring of the conversion, of Y, Cu and BaF2 precursors to form superconductor thin films has been achieved using a fluorine-specific-ion electrode immersed in an effluent gas-washing cell. High-quality thin films of YBa2Cu3O7-x deposited on NdGaO3, LaAlO3 and LaGaO3, have been produced by limiting the wet oxygen annealing phase of the post-deposition anneal. When the films were over-annealed in humidified oxygen the superconducting transition temperature as measured by inductive methods and the crystal quality, determined by x-ray rocking curves were degraded. RP GARZON, FH (reprint author), LOS ALAMOS NATL LAB,MAIL STOP D 429,LOS ALAMOS,NM 87545, USA. NR 5 TC 4 Z9 4 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1992 VL 21 IS 5 BP 483 EP 485 DI 10.1007/BF02655613 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA HV239 UT WOS:A1992HV23900003 ER PT J AU WU, XD LUO, L MUENCHAUSEN, R FOLTYN, SR DYE, RC NOGAR, NS AF WU, XD LUO, L MUENCHAUSEN, R FOLTYN, SR DYE, RC NOGAR, NS TI NEW BUFFER MATERIALS FOR HIGH-TC SUPERCONDUCTING THIN-FILMS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 33RD ELECTRONIC MATERIALS CONF CY JUN, 1991 CL BOULDER, CO DE YBCO; HIGH TC SUPERCONDUCTORS; OXIDE BUFFER LAYERS ID LASER DEPOSITION AB We have tested La2O3, Gd2O3, Y2O3, Dy2O3, and PrO1.82 as new buffer materials for high T(c) superconducting thin films. These oxides are structurally compatible with the superconductors. The cubic phase of La2O3 cannot be stabilized and Nd2O3 films have mixed cubic and hexagonal phases in the temperature and pressure ranges used in the experiment. All other oxides are suitable and also chemically compatible with YBa2Cu3O7-delta superconductor. YBa2Cu3O7-delta thin films on these buffer materials have a superconducting transition temperature of 90 K. (100) oriented films of these oxides were not obtained on R-plane sapphire without a CeO2 seed layer. RP WU, XD (reprint author), LOS ALAMOS NATL LAB,CTR EXPLORATORY RES & DEV,LOS ALAMOS,NM 87545, USA. NR 10 TC 9 Z9 9 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1992 VL 21 IS 5 BP 495 EP 498 DI 10.1007/BF02655615 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA HV239 UT WOS:A1992HV23900005 ER PT J AU ARENDT, P ELLIOTT, N DYE, R HUBBARD, K MALEY, M MARTIN, J COULTER, Y BENNETT, B AF ARENDT, P ELLIOTT, N DYE, R HUBBARD, K MALEY, M MARTIN, J COULTER, Y BENNETT, B TI FABRICATION AND CHARACTERIZATION OF TI-BA-CA-CU-O SUPERCONDUCTING FILMS ON LAAIO3 SUBSTRATES SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 33RD ELECTRONIC MATERIALS CONF CY JUN, 1991 CL BOULDER, CO DE TIBACACUO FILMS; SUPERCONDUCTIVITY; LAAIO3 SUBSTRATES ID CRITICAL CURRENTS; TAPES AB A multi-step process is used to fabricate Tl2Ba2Ca1Cu2O8 films on (100) LaAlO3 substrates. Submicron thick precursor films of Ba-Ca-Cu-O are rf magnetron sputter deposited from a single target. Film stoichiometry is measured by ion beam backscattering spectroscopy. Deficiencies of the alkaline earths that are found in the precursor films are then compensated for by the addition of appropriate CaF2 and/or BaF2 films onto the surface of the precursor film. Post deposition annealing of the films is then done in an atmosphere of thallium oxide and oxygen in order to form the superconducting phases. The annealed films are examined using x-ray diffraction (XRD), an ac inductance technique, and critical current in an external magnetic field. XRD shows the c-axis length of the superconducting phase to increase as the overall film stoichiometry approaches 2212. The transition widths measured by inductive coupling weakly correlate with 77 K critical current measurements. Our best critical current results are 1.5 * 10(6) amps/cm2 for a film measured at 4 K in an 8 T magnetic field (parallel to the films' c-axis). RP ARENDT, P (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 13 TC 7 Z9 7 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1992 VL 21 IS 5 BP 499 EP 501 DI 10.1007/BF02655616 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA HV239 UT WOS:A1992HV23900006 ER PT J AU SUNWOO, AJ MORRIS, JW LUCEY, GK AF SUNWOO, AJ MORRIS, JW LUCEY, GK TI SOLDERABILITY OF PRE-TINNED CU SHEET SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 33RD ELECTRONIC MATERIALS CONF CY JUN, 1991 CL BOULDER, CO DE WETTING KINETICS; CU-SN INTERMETALLICS; CARBON CONTAMINATION AB The reliability and integrity of pre-tinned copper-clad printed circuit (PC) boards are serious concerns in the manufacture of electronic devices. The factors that influence the wetting during soldering of Cu are discussed. The results suggest that pre-tinning with a Pb-rich solder, such as 95Pb-5Sn, is preferred to pre-tinning with eutectic solder, since the latter can develop exposed intermetallics during aging that wet poorly. The results also confirm that the use of flux leads to carbon contamination in the solder. C1 LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI,BERKELEY,CA 94720. USA,HARRY DIAMOND LABS,ADELPHI,MD 20783. RP SUNWOO, AJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 TC 4 Z9 4 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1992 VL 21 IS 5 BP 549 EP 557 DI 10.1007/BF02655623 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA HV239 UT WOS:A1992HV23900013 ER PT J AU RAILSBACK, SF BOWNDS, JM SALE, MJ STEVENS, MM TAYLOR, GH AF RAILSBACK, SF BOWNDS, JM SALE, MJ STEVENS, MM TAYLOR, GH TI AERATION AT OHIO RIVER BASIN NAVIGATION DAMS - CLOSURE SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Discussion C1 FED ENERGY REGULATORY COMMISS,OFF HYDROPOWER LICENSING,WASHINGTON,DC 20426. OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831. RP RAILSBACK, SF (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. OI Railsback, Steven/0000-0002-5923-9847 NR 2 TC 0 Z9 0 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD MAY-JUN PY 1992 VL 118 IS 3 BP 447 EP 451 DI 10.1061/(ASCE)0733-9372(1992)118:3(447.2) PG 5 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA HV096 UT WOS:A1992HV09600014 ER PT J AU REEVES, GD CAYTON, TE GARY, SP BELIAN, RD AF REEVES, GD CAYTON, TE GARY, SP BELIAN, RD TI THE GREAT SOLAR ENERGETIC PARTICLE EVENTS OF 1989 OBSERVED FROM GEOSYNCHRONOUS ORBIT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PROTON DRIFT ECHOES; INJECTION; 6.6-RE AB Los Alamos energetic proton instruments at geosynchronous orbit observed more major solar energetic particle events during 1989 than any other year since this series of detectors began observations in 1976. The temporal flux profiles of four intervals, which contain six distinct events, are compared illustrating the uniqueness of each event. Characteristic risetime and decay time are computed for each event. During two of these events, brief order-of-magnitude increases of the proton flux are observed. They are associated with sudden commencement events and dramatic changes in the solar wind. We conclude that these two brief events are likely the result of shock acceleration in the solar wind. We have fit the measured count rates to a spectral form which is exponential in rigidity, and we have examined the changes in spectral slope with time for each of the four intervals. In general, harder spectra are measured near the onset of an event followed by a softening of the spectrum as the fluxes decay. We have also investigated the effects of these events on geomagnetic activity by comparing the fluxes of > 30-keV electrons at geosynchronous orbit and Kp geomagnetic index during the early part of two of the solar energetic particle events. RP REEVES, GD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 21 TC 27 Z9 27 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1992 VL 97 IS A5 BP 6219 EP 6226 DI 10.1029/91JA03102 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HT743 UT WOS:A1992HT74300001 ER PT J AU REEVES, GD KETTMANN, G FRITZ, TA BELIAN, RD AF REEVES, GD KETTMANN, G FRITZ, TA BELIAN, RD TI FURTHER INVESTIGATION OF THE CDAW-7 SUBSTORM USING GEOSYNCHRONOUS PARTICLE DATA - MULTIPLE INJECTIONS AND THEIR IMPLICATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA SHEET; MAGNETOSPHERIC SUBSTORMS; MAGNETOTAIL; PHASE; ONSET; DISRUPTION; DIVERSION; BOUNDARY; DYNAMICS; GROWTH AB A substorm which occurred on April 24, 1979 was the subject of the CDAW 7 workshop and several in-depth studies of ISEE and ground-based data. In this paper we continue the analysis by looking in detail at geosynchronous energetic particle data from the Los Alamos charged particle analyzer instruments. Observations show three distinct injection events during this substorm. We have used a drift shell tracing technique to determine the time and location on the geosynchronous drift shell of each injection region. We then compare the timing of events on the ground, in the tail and at geosynchronous orbit. The first injection is very closely associated with observations from ISEE and ground-based measurements which have been interpreted as the signatures of plasmoid formation in the near-Earth tail. The later two injections occurred while ISEE 1 and 2 were in the lobes following the exit of the plasmoid downtail. All three injections are calculated to have originated in the same local time sector in which the ISEE spacecraft were located and also to have overlapped one another in local time extent These observations show that the spatial and temporal evolution of the substorm is more dynamic than previous studies have implied. We have considered possible interpretations of the more complete set of observations the context of the both the traditional near-Earth neutral line model and the inner magnetospheric current disruption model. Either model can provide an interpretation of the data but neither by itself, provides a completely satisfactory explanation. We suggest a new synthesis of these two models which provides a simple interpretation for all the observations. We propose that reconnection in the tail initiates the substorm but diverts much of the cross-tail current around the reconnection region enhancing the near-Earth cross-tail current. This creates an unstable situation and current disruptions dipolarize the field in three steps creating the three injections. RP REEVES, GD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 42 TC 34 Z9 34 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1992 VL 97 IS A5 BP 6417 EP 6428 DI 10.1029/91JA03103 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HT743 UT WOS:A1992HT74300018 ER PT J AU GOSLING, JT MCCOMAS, DJ PHILLIPS, JL BAME, SJ AF GOSLING, JT MCCOMAS, DJ PHILLIPS, JL BAME, SJ TI COUNTERSTREAMING SOLAR-WIND HALO ELECTRON EVENTS - SOLAR-CYCLE VARIATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID HELIOS PLASMA-EXPERIMENT; CORONAL TRANSIENTS; SKYLAB AB Previous work has suggested that counterstreaming solar wind halo electron events are a reliable signature of coronal mass ejections, CMEs, in the solar wind at 1 AU. Using observations of counterstreaming events made by the Los Alamos plasma experiment on ISEE 3 / ICE, we have determined the percentage of time that counterstreaming was observed each year during an approximately 12.4-year interval extending from August 1978 through December 1990. These annual percentages vary roughly in phase and amplitude both with the 11-year sunspot cycle and with annual CME rates derived from coronagraph observations. The total variation in annual percentages over the solar cycle was approximately a factor of 21. Near solar activity maximum, counterstreaming events accounted for approximately 14.7% of all ISEE 3 / ICE solar wind measurements, while near solar minimum they accounted for approximately 0.7% of all the measurements. Inferred rates of counterstreaming events at a single point in the ecliptic plane ranged from approximately 72/yr near solar maximum to less than 12/yr near solar minimum. These inferred rates axe in reasonable quantitative accord with predicted rates for CME events in the ecliptic plane derived from SMM coronagraph observations, further supporting the thesis that most CMEs in the solar wind at 1 AU can be reliably identified by the counterstreaming electron signature. RP UNIV CALIF LOS ALAMOS SCI LAB, MS D438, LOS ALAMOS, NM 87544 USA. NR 27 TC 57 Z9 59 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1992 VL 97 IS A5 BP 6531 EP 6535 DI 10.1029/92JA00302 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HT743 UT WOS:A1992HT74300027 ER PT J AU SERGEEV, VA BOSINGER, T BELIAN, RD REEVES, GD CAYTON, TE AF SERGEEV, VA BOSINGER, T BELIAN, RD REEVES, GD CAYTON, TE TI DRIFTING HOLES IN THE ENERGETIC ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT FOLLOWING SUBSTORM ONSET SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID PARTICLE MEASUREMENTS; SYNCHRONOUS ORBIT; CURRENT SHEET; PLASMA SHEET; GROWTH-PHASE; MAGNETOSPHERE; 6.6-RE; ECHOES; REGION AB A new type of substorm-related particle flux change was discovered at geosynchronous orbit. It is manifested as a decrease in energetic electron flux (of initial duration about 1-2 min) starting near local magnetic midnight at a time of high-energy particle injection to geosynchronous distance. Unlike "dropouts," which are observed only in the midnight local time sector, this flux signature drifted eastward showing the typical energy and LT dependent time patterns of electron drift. This phenomenon was seen only in electron fluxes above a certain threshold energy and was characterized by a moderate amplitude of flux variation (within a factor of 3). Below the threshold energy the normal substorm-associated increase in electron flux (drifting cloud of accelerated particles) was detected. The phenomenon in question, called a drifting electron hole, is explained as being a result of adiabatic redistribution of an already existing high-energy electron component recently described by Cayton et al. (1989). It is argued that in the case of a strong (inward directed) radial gradient of electron flux and of a hard energy spectrum the electron fluxes which are brought to a lower drift shell by the inward injection may still be smaller than the previously existing fluxes at this drift shell. This leads to an apparent loss of electrons in some localized portion of the drift shells (e.g., at geosynchronous orbit). Another explanation of the drifting electron hole based on rapid particle losses due to precipitation seems less probable. C1 UNIV OULU,DEPT PHYS,SF-90570 OULU,FINLAND. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. RP SERGEEV, VA (reprint author), UNIV ST PETERSBURG,INST PHYS,198904 ST PETERSBURG,USSR. RI Reeves, Geoffrey/E-8101-2011; Sergeev, Victor/H-1173-2013 OI Reeves, Geoffrey/0000-0002-7985-8098; Sergeev, Victor/0000-0002-4569-9631 NR 19 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1992 VL 97 IS A5 BP 6541 EP 6548 DI 10.1029/92JA00182 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HT743 UT WOS:A1992HT74300029 ER PT J AU SORENSEN, JH CARNES, SA ROGERS, GO AF SORENSEN, JH CARNES, SA ROGERS, GO TI AN APPROACH FOR DERIVING EMERGENCY PLANNING ZONES FOR CHEMICAL MUNITIONS EMERGENCIES SO JOURNAL OF HAZARDOUS MATERIALS LA English DT Article AB The selection of an emergency planning zone (EPZ) for hazardous materials is often a difficult technical as well as a political task. This paper describes a method used in the United States to establish EPZs in the Army's Chemical Stockpile Emergency Preparedness Program. A rationale for a zoned based approach to emergency planning for hazardous materials is developed. The method presented integrates risk analysis data with meteorological, topographical, demographic, and political concerns. The method is then applied at the Tooele Army Depot in Tooele, Utah. Although the analysis concerns chemical weapons, the process is relevant to other hazardous material problems. C1 TEXAS A&M UNIV SYST,COLL ARCHITECTURE,CTR HAZARD REDUCT & RECOVERY,COLLEGE STN,TX 77843. RP SORENSEN, JH (reprint author), OAK RIDGE NATL LAB,POB 2008,BLDG 4500N,MS 6206,OAK RIDGE,TN 37831, USA. NR 33 TC 13 Z9 13 U1 2 U2 2 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 MAY PY 1992 VL 30 IS 3 BP 223 EP 242 DI 10.1016/0304-3894(92)87001-V PG 20 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA JA797 UT WOS:A1992JA79700001 ER PT J AU DAUGHERTY, ML WATSON, AP VO-DINH, T AF DAUGHERTY, ML WATSON, AP VO-DINH, T TI CURRENTLY AVAILABLE PERMEABILITY AND BREAKTHROUGH DATA CHARACTERIZING CHEMICAL WARFARE AGENTS AND THEIR SIMULANTS IN CIVILIAN PROTECTIVE CLOTHING MATERIALS SO JOURNAL OF HAZARDOUS MATERIALS LA English DT Article AB The current analysis characterizes chemical protective clothing (CPC) that would be available to civilian emergency personnel responding to possible nerve or vesicant chemical warfare agent release with off-post consequences. Currently available commercial protective garments found in the public domain were identified through contacts with manufacturers, regulatory bodies, and distributors of protective clothing, as well as civilian emergency response personnel who use CPC. When appropriate data were available, individual protective clothing ensembles were further characterized by chemical resistance data for specific agents or their simulants. The literature analysis revealed a wide range of chemical protective garments that have been incompletely evaluated for use in a chemical agent environment. RP DAUGHERTY, ML (reprint author), OAK RIDGE NATL LAB, POB 2001, MS 6050, OAK RIDGE, TN 37831 USA. NR 54 TC 7 Z9 7 U1 1 U2 3 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 MAY PY 1992 VL 30 IS 3 BP 243 EP 267 DI 10.1016/0304-3894(92)87002-W PG 25 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA JA797 UT WOS:A1992JA79700002 ER PT J AU NIMICK, FB LEITH, JR AF NIMICK, FB LEITH, JR TI A MODEL FOR THERMAL-CONDUCTIVITY OF GRANULAR POROUS-MEDIA SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Note DE GEOPHYSICAL HEAT TRANSFER; POROUS MEDIA; THERMOPHYSICAL PROPERTIES C1 UNIV NEW MEXICO,DEPT MECH ENGN,ALBUQUERQUE,NM 87131. RP NIMICK, FB (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 8 TC 7 Z9 7 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD MAY PY 1992 VL 114 IS 2 BP 505 EP 508 DI 10.1115/1.2911302 PG 4 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HW623 UT WOS:A1992HW62300028 ER PT J AU HEDRICK, DB WHITE, T GUCKERT, JB JEWELL, WJ WHITE, DC AF HEDRICK, DB WHITE, T GUCKERT, JB JEWELL, WJ WHITE, DC TI MICROBIAL BIOMASS AND COMMUNITY STRUCTURE OF A PHASE-SEPARATED METHANOGENIC REACTOR DETERMINED BY LIPID ANALYSIS SO JOURNAL OF INDUSTRIAL MICROBIOLOGY LA English DT Article DE ACETOGENESIS; BIOMARKERS; CLUSTER ANALYSIS; FERMENTATION ID FATTY-ACID; SEDIMENTS AB An anaerobic phase-separation biomass reactor was established on cellulose with the hyrolysis and fermentation steps occurring in the first stage. and acetogenesis and methanogenesis in the second stage. Based upon lipid biomarker analysis eubacterial and eukaryotic cells accounted for approximately 6% of the volatile solids of the first stage and 17% of the second, while methanogens were approximately 1% of the volatile solids in the first stage and 9% of the second. Clustering the polar lipid fatty acids into groups based upon their distributions between the two stages of the reactor clarified the differences in community structure caused by phase-separated operation. Although inoculated from the same source, the two stages maintained very different microbial communities. Signature fatty acids known as indicators of unbalanced growth in eubacteria were significantly higher in the first stage of the reactor. C1 CORNELL UNIV,DEPT AGR & BIOL ENGN,ITHACA,NY 14853. UNIV TENNESSEE,DEPT MICROBIOL,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN. RP HEDRICK, DB (reprint author), UNIV TENNESSEE,INST APPL MICROBIOL,KNOXVILLE,TN 37932, USA. NR 25 TC 8 Z9 9 U1 1 U2 1 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE, HAMPSHIRE, ENGLAND RG21 6XS SN 0169-4146 J9 J IND MICROBIOL JI J. Indust. Microbiol. PD MAY-JUN PY 1992 VL 9 IS 3-4 BP 193 EP 199 DI 10.1007/BF01569623 PG 7 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA JD731 UT WOS:A1992JD73100005 ER PT J AU BABU, GRV WOLFRAM, JH CHAPATWALA, KD AF BABU, GRV WOLFRAM, JH CHAPATWALA, KD TI CONVERSION OF SODIUM-CYANIDE TO CARBON-DIOXIDE AND AMMONIA BY IMMOBILIZED CELLS OF PSEUDOMONAS-PUTIDA SO JOURNAL OF INDUSTRIAL MICROBIOLOGY LA English DT Article DE BIODEGRADATION; PSEUDOMONAS-PUTIDA; IMMOBILIZATION; SODIUM CYANIDE ID DEGRADATION; SYSTEM AB Pseudomonas putida, isolated from contaminated industrial wastewaters and soil sites, was found to utilize sodium cyanide (NaCN) as a sole source of carbon and nitrogen. Cells, immobilized in calcium alginate beads (1-2 mm diameter) were aerated in air-uplift-type fluidized batch bioreactor containing 100-400 ppm of NaCN. Degradation of NaCN was monitored for 168 h by analyzing gaseous and dissolved ammonia (NH3), CO2, pH and optical density. The results indicated that the alginate-immobilized cells of P. putida were able to degrade NaCN into NH3 and CO2 in a time-dependent manner. C1 SELMA UNIV,DIV NAT SCI,SELMA,AL 36701. EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83401. NR 17 TC 17 Z9 19 U1 0 U2 2 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE, HAMPSHIRE, ENGLAND RG21 6XS SN 0169-4146 J9 J IND MICROBIOL JI J. Indust. Microbiol. PD MAY-JUN PY 1992 VL 9 IS 3-4 BP 235 EP 238 DI 10.1007/BF01569629 PG 4 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA JD731 UT WOS:A1992JD73100011 ER PT J AU CALLAWAY, JC MORIMOTO, H GYNTHER, J AIRAKSINEN, MM WILLIAMS, PG AF CALLAWAY, JC MORIMOTO, H GYNTHER, J AIRAKSINEN, MM WILLIAMS, PG TI SYNTHESIS OF [H-3)PINOLINE, AN ENDOGENOUS TETRAHYDRO-BETA-CARBOLINE SO JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS LA English DT Article DE TRITIUM NMR; PINOLINE; BETA-CARBOLINE; TRYPTAMINE; ENDOGENOUS ID BRAIN AB Pinoline (6-methoxy-1,2,3,4-tetrahyro-9H-pyrido[3,4-b]indole) is an endogenous beta-carboline thought to be synthesized in the pineal gland from serotonin. It is a strong inhibitor of MAO-A and can displace [H-3]citalopram from the 5-HT uptake site on human platelets in nM concentrations. The hydrochloride salt of 6-MeO-DH-beta-C (6-methoxy-1,2-dihydro-9H-pyrido[3,4-b]indole), also a new compound, was synthesized as the immediate precursor to the title compound. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL TRITIUM LABELING FACIL,BERKELEY,CA 94720. UNIV KUOPIO,DEPT PHARMACOL & TOXICOL,SF-70211 KUOPIO,FINLAND. RP CALLAWAY, JC (reprint author), UNIV KUOPIO,DEPT PHARMACEUT CHEM,POB 1627,SF-70211 KUOPIO,FINLAND. NR 14 TC 8 Z9 8 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0362-4803 J9 J LABELLED COMPD RAD JI J. Label. Compd. Radiopharm. PD MAY PY 1992 VL 31 IS 5 BP 355 EP 364 DI 10.1002/jlcr.2580310504 PG 10 WC Biochemical Research Methods; Chemistry, Medicinal; Chemistry, Analytical SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Chemistry GA HT184 UT WOS:A1992HT18400003 ER PT J AU WEISS, JD AF WEISS, JD TI PULSED RADIATION-INDUCED ATTENUATION IN CERTAIN OPTICAL FIBERS SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article ID STEADY-STATE EXPOSURES AB Using the X-ray pulse from the HERMES 11 simulation machine at Sandia National Laboratories, we measured the pulsed radiation-induced attenuation in two optical fibers considered to be "non-rad-hard": the 50-mu-core, graded-index fiber from Corning and the plastic (PMMA) fiber from the Mitsubishi Rayon Company. These fibers were exposed to radiation up to doses of 19.5 and 28 krad(Si), respectively. In addition, fits of their post-radiation recovery were made to the geminate recombination model, from which the recombination-rate and generation constants, characteristic of this theory, were determined. These parameters should be useful in determining the response of the fibers to radiation conditions other than those encountered here. RP WEISS, JD (reprint author), SANDIA NATL LABS,FIELD MEASUREMENTS DIV 9313,ALBUQUERQUE,NM 87185, USA. NR 18 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD MAY PY 1992 VL 10 IS 5 BP 531 EP 538 DI 10.1109/50.136084 PG 8 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA HU282 UT WOS:A1992HU28200002 ER PT J AU WILLIAMS, PT VRANIZAN, KM KRAUSS, RM AF WILLIAMS, PT VRANIZAN, KM KRAUSS, RM TI CORRELATIONS OF PLASMA-LIPOPROTEINS WITH LDL SUBFRACTIONS BY PARTICLE-SIZE IN MEN AND WOMEN SO JOURNAL OF LIPID RESEARCH LA English DT Article DE GRADIENT GEL ELECTROPHORESIS; VERY LOW DENSITY LIPOPROTEINS; LOW DENSITY LIPOPROTEINS; HIGH DENSITY LIPOPROTEINS; SEX DIFFERENCES ID GRADIENT GEL-ELECTROPHORESIS; LOW-DENSITY LIPOPROTEINS; POSTMENOPAUSAL WOMEN; SUBCLASS PATTERNS; APOLIPOPROTEINS; CHOLESTEROL; PRECIPITATION; QUANTITATION; EXERCISE; RISK AB Nondenaturing gradient gel electrophoresis of plasma low density lipoprotein (LDL) has been used to identify major LDL subclasses that are influenced by genetic and other factors. In the present paper, this technique has been extended by measuring absorbance of lipid- or protein-stained gels as an index of concentration at intervals of 0.05 nm across the entire LDL particle size range (21.8-30 nm) in moderately overweight men (n = 115) and women (n = 78). When LDL absorbance levels were correlated with other lipoprotein variables, we found that the strengths of the correlations with each of triglycerides, apolipoprotein (apo) B, high density lipoprotein (HDL)2, and apoA-I achieve relative maximum values for two regions within the small LDL range (21-26 nm), one within LDL-IVB (22-23.2 nm) and a second within LDL-III (24.2-25.5 nm). We also found that the increase in LDL accompanying higher triglyceride levels occurs below 25.5 nm in men and between 24.5 and 26.5 nm in women, suggesting either that triglycerides are related to different LDL subclasses in men and women, or that particle sizes of metabolically homologous LDL subclasses may differ in men and women. As compared to analytic ultracentrifuge measurements, gradient gel measurements of LDL absorbance by the procedure described here provide greater resolution of LDL subclasses but less precision in estimating LDL levels. RP WILLIAMS, PT (reprint author), LAWRENCE BERKELEY LAB,DIV RES MED & RADIAT BIOPHYS,1 CYCLOTRON RD,47A,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL-24462, HL-02183, HL-18574] NR 21 TC 56 Z9 56 U1 0 U2 1 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD MAY PY 1992 VL 33 IS 5 BP 765 EP 774 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA HW810 UT WOS:A1992HW81000015 PM 1619368 ER PT J AU KOESTLER, C CHANDRAMOULI, M THOMAS, G SCHULTZ, L AF KOESTLER, C CHANDRAMOULI, M THOMAS, G SCHULTZ, L TI MICROSTRUCTURE OF MECHANICALLY ALLOYED ND16FE76B8-MAGNETS SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article ID FE-B MAGNETS; MAGNETIZATION REVERSAL AB High resolution electron microscopy and analytical electron microscopy were used to characterize mechanically alloyed Nd16Fe76B8 which were previously identified as isotropic and anisotropic magnets. In both samples, two rare earth-oxide phases, NdO and Nd2O3, and a boron-rich phase were observed. Two grain boundary phases, the NdFe2-phase and a non-equilibrium Nd-rich phase, were clearly identified in the isotropic samples and seem to be responsible for their higher coercivity. Due to the alignment of the grains, the anisotropic materials possess a better squareness of the B-H loop and a higher energy product. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720. SIEMENS AG,RES LABS,W-8520 ERLANGEN,GERMANY. RI Schultz, Ludwig/B-3383-2010 NR 25 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAY PY 1992 VL 110 IS 3 BP 264 EP 274 DI 10.1016/0304-8853(92)90211-6 PG 11 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA JD155 UT WOS:A1992JD15500006 ER PT J AU THADHANI, NN WORK, S GRAHAM, RA HAMMETTER, WF AF THADHANI, NN WORK, S GRAHAM, RA HAMMETTER, WF TI SHOCK-INDUCED REACTION SYNTHESIS (SRS) OF NICKEL ALUMINIDES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID TRANSFORMATION; COMBUSTION; ALLOYS; POWDER AB Shock-induced chemical reactions between nickel and aluminum powders (mixed in Ni3Al stoichiometry) are used for the synthesis of nickel aluminides. It is shown that the extent of shock-induced chemical reactions and the nature of the shock-synthesized products are influenced by the morphology of the starting powders. Irregular (flaky type) and fine morphologies of the powders undergo complete reactions in contrast to partial reactions occurring in coarse and uniform morphology powders under identical shock loading conditions. Furthermore, irregular morphology powders result in the formation of the equiatomic (B2 phase) NiAl compound while the Ni3Al (L1(2) phase) compound is the reaction product with coarse and regular morphology powders. Shock-induced reaction synthesis can be characterized as a bulk reaction process involving an intense "mechanochemical" mechanism. It is a process in which shock compression induces fluid-like plastic flow and mixing, and enhances the reactivity due to the introduction of defects and cleansing of particle surfaces, which strongly influence the synthesis process. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP THADHANI, NN (reprint author), NEW MEXICO INST MIN & TECHNOL,CTR EXPLOS TECHNOL RES,SOCORRO,NM 87801, USA. NR 51 TC 15 Z9 15 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1992 VL 7 IS 5 BP 1063 EP 1075 DI 10.1557/JMR.1992.1063 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA HT106 UT WOS:A1992HT10600005 ER PT J AU RAWERS, J ASAI, G DOAN, R DUNNING, J AF RAWERS, J ASAI, G DOAN, R DUNNING, J TI MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF NITROGEN-HIGH PRESSURE MELTED FE-CR-NI ALLOYS SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB A series of iron-chromium-nickel alloys was melted under a nitrogen atmosphere at several different pressures. Nitrogen-high pressure melting (N-HPM) was conducted under pressures ranging from 0.1 to 200 MPa. The total nitrogen concentrations achieved in these alloys were proportional to the square root of the nitrogen pressure used during melting. Nitrogen took the form of soluble interstitial nitrogen and metal nitride precipitates, FexN and CrN. Tensile properties of N-HPM alloys were directly proportional to the nitrogen concentration in the alloy. RP RAWERS, J (reprint author), US BUR MINES,ALBANY RES CTR,ALBANY,OR 97321, USA. NR 16 TC 17 Z9 17 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1992 VL 7 IS 5 BP 1083 EP 1092 DI 10.1557/JMR.1992.1083 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA HT106 UT WOS:A1992HT10600007 ER PT J AU KNOLL, RW HENAGER, CH AF KNOLL, RW HENAGER, CH TI OPTICAL AND PHYSICAL-PROPERTIES OF SPUTTERED SI-AL-O-N FILMS SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; SILICON-NITRIDE; THIN-FILM; MICROSTRUCTURE AB Mechanical and optical properties and structural characteristics are described for Si : N films with Al and O additions (SixAl1-xOyN1-y) deposited by reactive RF diode sputtering on Si and SiO2 substrates. The thermal and intrinsic stress components, elastic stiffness, coefficient of thermal expansion (CTE), and refractive index were measured for films ranging in thickness from approximately 2-mu-m to 50-mu-m. Some structural and microstructural data were obtained using x-ray diffraction, optical and scanning-electron microscopy, and surface profilometry. Alloying Si : N with Al to form Si : Al : N greatly reduced the compressive intrinsic and total stress found in pure Si : N films on Si. Addition of O to the Si : Al : N moderately increased the intrinsic stress, decreased the elastic stiffness, and produced a smoother, more glassy (amorphous) film. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP KNOLL, RW (reprint author), JOHNSON CONTROL INC, MILWAUKEE, WI 53202 USA. NR 15 TC 5 Z9 5 U1 2 U2 6 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1992 VL 7 IS 5 BP 1247 EP 1252 DI 10.1557/JMR.1992.1247 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA HT106 UT WOS:A1992HT10600027 ER PT J AU XU, M VOILES, ET CHUMBLEY, LS GOLDMAN, AI FINNEMORE, DK AF XU, M VOILES, ET CHUMBLEY, LS GOLDMAN, AI FINNEMORE, DK TI SYNTHESIS AND CHARACTERIZATION OF CERAMIC (SR1-XCAX)2CUO3 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID PHASE-EQUILIBRIA; CU-O; SYSTEM AB Ceramic (Sr1-xCax)2CuO3 samples have been prepared with x = 0.00, 0.25, 0.50, 0.55, 0.75, and 1.00 in order to study the change in lattice constants with the ratio of Sr/Ca. This phase is frequently an impurity phase in the fabrication of Bi-Sr-Ca-Cu-O superconductors, and it is important to be able to connect the lattice constants with stoichiometry. The behavior of the lattice constants closely follows Vegard's law. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP XU, M (reprint author), US DOE,AMES LAB,DEPT PHYS,AMES,IA 50011, USA. NR 11 TC 10 Z9 10 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1992 VL 7 IS 5 BP 1283 EP 1285 DI 10.1557/JMR.1992.1283 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA HT106 UT WOS:A1992HT10600032 ER PT J AU HARVEY, SD BEAN, RM UDSETH, HR AF HARVEY, SD BEAN, RM UDSETH, HR TI HIGH-RESOLUTION SEPARATION AND DETECTION OF DNA ADDUCTS OF BENZO[A]PYRENE SO JOURNAL OF MICROCOLUMN SEPARATIONS LA English DT Article DE BENZO[A]PYRENE-ADDUCTED DNA; CAPILLARY ZONE ELECTROPHORESIS; MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY; MICROCOLUMN HPLC; ELECTROSPRAY IONIZATION MASS SPECTROMETRY ID CAPILLARY ZONE ELECTROPHORESIS; MOUSE EPIDERMAL DNA; DIOL-EPOXIDE; COVALENT BINDING; TOPICAL APPLICATION; MICELLAR SOLUTIONS; INVITRO REACTION; DOSE-RESPONSE; NUCLEIC-ACIDS; SKIN AB Analysis of DNA adducts as indicators of human exposure to environmental levels of carcinogenic compounds represents an extreme challenge for trace analyses to chemists. At environmental exposure levels of benzo[a]pyrene, one can expect less than one adduct per 10(7) base pairs, or roughly 30 femtomoles of adduct per mg DNA. Microcolumn separation techniques are ideally suited for the trace analysis of DNA adducts due to the high separation efficiency, enhanced mass flow sensitivity, and ease of interfacing with highly specific and sensitive mass spectrometric detectors. This study describes the analysis of benzo[a]pyrene-adducted deoxyguanosine-5'-monophosphate with micellar electrokinetic capillary chromatographic separation followed by fluorescence detection. Alternatively, adducts can be cleaved from the DNA by treatment with acid, resulting in the formation of highly fluorescent benzo[a]pyrene tetrahydrotetrols. Analysis of the tetrahydrotetrols by either capillary zone electrophoresis or microcolumn HPLC with fluorescence detection is described, Detection limits for the benzo[a]pyrene tetrahydrotetrols with either of the aforementioned separation techniques were approximately 3 femtomoles. RP HARVEY, SD (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 36 TC 8 Z9 8 U1 1 U2 1 PU MICROSEPARATIONS INC PI PROVO PA DEPT CHEM BRIGHAM YOUNG UNIV, PROVO, UT 84602-1022 SN 1040-7685 J9 J MICROCOLUMN SEP JI J. Microcolumn Sep. PD MAY-JUN PY 1992 VL 4 IS 3 BP 191 EP 198 DI 10.1002/mcs.1220040303 PG 8 WC Chemistry, Analytical SC Chemistry GA HW205 UT WOS:A1992HW20500002 ER PT J AU LOO, BW WILLIAMS, S MEIZEL, S ROTHMAN, SS AF LOO, BW WILLIAMS, S MEIZEL, S ROTHMAN, SS TI X-RAY STEREOMICROSCOPY - HIGH-RESOLUTION 3-D IMAGING OF HUMAN SPERMATOZOA IN AQUEOUS SUSPENSION WITH NATURAL CONTRAST SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Note C1 UNIV CALIF DAVIS,SCH MED,DAVIS,CA 95616. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. UNIV CALIF DAVIS,DEPT CELL BIOL & ANAT,DAVIS,CA 95616. UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. RP LOO, BW (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. FU NICHD NIH HHS [HD-23098] NR 5 TC 9 Z9 9 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD MAY PY 1992 VL 166 BP RP5 EP RP6 PN 2 PG 2 WC Microscopy SC Microscopy GA HW411 UT WOS:A1992HW41100010 PM 1625335 ER PT J AU DAVIS, PJ BRINKER, CJ SMITH, DM AF DAVIS, PJ BRINKER, CJ SMITH, DM TI PORE STRUCTURE EVOLUTION IN SILICA-GEL DURING AGING DRYING .1. TEMPORAL AND THERMAL AGING SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID SPIN-LATTICE RELAXATION; NMR TECHNIQUE; SHRINKAGE; MECHANICS; SYNERESIS; MODULUS; SIZE AB Low field NMR spin-lattice relaxation measurements of pore fluids contained in silica gels are employed as a pore structure probe to ascertain the changes that occur in a two-step acid/base-catalyzed silica gel during aging in its mother liquor. It has been shown that both a narrowing of pore size distribution and an increase in mean pore size is obtained for a gel aged at 303 K over a time period of several weeks. By increasing the aging temperature from 303 to 333 K, the time required for this same degree of pore size distribution narrowing is decreased by an order of magnitude. Increasing the gel solids content from 15 to 30 wt% SiO2 results in smaller pore sizes and pore volumes (a factor of approximately 2) but a similar pore size narrowing with comparable kinetics. In contrast, little change in pore structure is observed in a two-step acid-catalyzed gel aged in its mother liquor at 303 K for similar time periods. C1 UNIV NEW MEXICO,NATL SCI FDN,CTR MICROENGINEERED CERAM,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,DIV 1846,ALBUQUERQUE,NM 87185. NR 21 TC 72 Z9 73 U1 2 U2 19 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 MAY PY 1992 VL 142 IS 3 BP 189 EP 196 DI 10.1016/S0022-3093(05)80025-0 PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA HX643 UT WOS:A1992HX64300001 ER PT J AU DAVIS, PJ BRINKER, CJ SMITH, DM ASSINK, RA AF DAVIS, PJ BRINKER, CJ SMITH, DM ASSINK, RA TI PORE STRUCTURE EVOLUTION IN SILICA-GEL DURING AGING DRYING .2. EFFECT OF PORE FLUIDS SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID NMR TECHNIQUE AB A two-step acid-base-catalyzed silica gel has been aged in a series of alcohol and water baths and some chemical and physical structures of the gel were measured using several techniques (low-field NMR, Si-29 and C-13 MAS-NMR, IR, Raman, nitrogen adsorption) on gels in wet and dry states. When the gel was placed in alcohol, the surface area increased as a result of esterification and depolymerization to 1500-2000 m2/g in the wet state which then decreased to 1000 m2/g after drying. In water, hydrolysis and condensation decreased surface area to 1000 m2/g (wet) and 500 m2/g (dry). This process was reversible. Alcohol-aging led to small pore size distributions (in much shorter times than previous studies of aging in the gel's mother liquor, approximately 90% ethanol, 10% H2O). Surface areas calculated from Si-29 MAS-NMR-derived Q distributions were in good agreement with adsorption-derived values for the samples dried from alcohol but water-dried samples appeared to contain some surface area which was inaccessible to adsorbing nitrogen after drying. These results indicate that the pore structure of silica gels may be dramatically altered during the aging process and that their wet gel features may be preserved (at least partially) upon drying. C1 SANDIA NATL LABS,DIV 1846,ALBUQUERQUE,NM 87185. SANDIA NATL LABS,DIV 1812,ALBUQUERQUE,NM 87185. RP DAVIS, PJ (reprint author), UNIV NEW MEXICO,NATL SCI FDN,CTR MICROENGINEERED CERAM,ALBUQUERQUE,NM 87131, USA. NR 18 TC 62 Z9 63 U1 1 U2 15 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 MAY PY 1992 VL 142 IS 3 BP 197 EP 207 DI 10.1016/S0022-3093(05)80026-2 PG 11 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA HX643 UT WOS:A1992HX64300002 ER PT J AU EMIG, JA GARZA, RG CHRISTENSEN, LD CORONADO, PR SOUERS, PC AF EMIG, JA GARZA, RG CHRISTENSEN, LD CORONADO, PR SOUERS, PC TI HELIUM RELEASE FROM 19-YEAR-OLD PALLADIUM TRITIDE SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID BUBBLES AB Eleven nineteen-year-old samples of palladium deuteride-tritide originally placed under 100 kPa of tritium have been monitored for pressure during their lifetimes. A model has been constructed, which relates the pressure to the tritium and He-3 concentrations inside the solid samples. Two tritide samples replenished with 2100 kPa of tritium throughout their lifetime started to copiously outgas He-3 at a helium/palladium atom ratio of 0.50 to 0.55. Four other samples were originally reacted with pure tritium and never replenished. These started to outgas mainly He-3 at a helium/palladium ratio of 0.36 to 0.37 at about one-eighth the rate of the replenished samples. All six samples started their outgassing at 6000 days. Two samples were made with D-T and replenished with tritium. Neither outgassed although the helium/palladium ratio is presently about 0.4. Three samples were also made with D-T and never replenished, and no outgassing was seen up to a helium/palladium ratio of 0.24. From the change in the volumes of two samples, we have calculated a helium bubble gas density of 1.8 x 10(5) mol/m3, in agreement with nuclear magnetic resonance data. RP EMIG, JA (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550, USA. NR 12 TC 24 Z9 31 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAY PY 1992 VL 187 IS 3 BP 209 EP 214 DI 10.1016/0022-3115(92)90499-B PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA HV687 UT WOS:A1992HV68700004 ER PT J AU GARNER, FA MITCHELL, MA AF GARNER, FA MITCHELL, MA TI THE COMPLEX ROLE OF PHOSPHORUS IN THE NEUTRON-INDUCED SWELLING OF TITANIUM-MODIFIED AUSTENITIC STAINLESS-STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ALLOYS; BEHAVIOR; CR; PRECIPITATION; IRRADIATION; SEGREGATION AB At very low levels (< 0.02 wt%), phosphorus additions to austenitic stainless steels often cause a substantial increase in void swelling. This phenomenon occurs in both simple model alloys and more complex solute-modified alloys typical of materials being considered for breeder reactor or fusion reactor service. This effect is observed in both annealed and cold-worked steels. At levels above 0.02% phosphorus, there is a reversal in behavior and swelling declines. This nonmonotonic behavior tends to occur at lower irradiation temperatures in relatively simple alloys, but often persists to much higher temperatures in more complex titanium-modified alloys employed in the fusion and breeder reactor programs. C1 UNIV ILLINOIS, URBANA, IL 61801 USA. RP GARNER, FA (reprint author), PACIFIC NW LAB, MAT RES DEPT, POB 999, RICHLAND, WA 99352 USA. NR 28 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAY PY 1992 VL 187 IS 3 BP 223 EP 229 DI 10.1016/0022-3115(92)90501-B PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA HV687 UT WOS:A1992HV68700006 ER PT J AU KENIK, EA AF KENIK, EA TI RADIATION-INDUCED SEGREGATION IN IRRADIATED TYPE-304 STAINLESS-STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Grain boundary radiation-induced segregation (RIS) in two Type 304 stainless steels neutron-irradiated at 288-degrees-C has been investigated by analytical electron microscopy. In the conventional alloy (CP), narrow (less-than-or-equal-to 5 nm width) RIS zones depleted in chromium and iron and enriched in silicon, phosphorus, and nickel were observed near grain boundaries. For the higher purity alloy (HP), similar width (less-than-or-equal-to 6 nm) RIS zones depleted in chromium and enriched in nickel and iron were observed at boundaries, though at reduced magnitudes relative to those in the CP material. No significant segregation of silicon or phosphorus was observed in the HP material. RIS zones associated with faulted dislocation loops in the CP material were detected and shown to be depleted in chromium and enriched in nickel and iron relative to the matrix. RP KENIK, EA (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 16 TC 44 Z9 44 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAY PY 1992 VL 187 IS 3 BP 239 EP 246 DI 10.1016/0022-3115(92)90503-D PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA HV687 UT WOS:A1992HV68700008 ER PT J AU HUANG, FH HAMILTON, ML AF HUANG, FH HAMILTON, ML TI THE FRACTURE-TOUGHNESS DATABASE OF FERRITIC ALLOYS IRRADIATED TO VERY HIGH NEUTRON EXPOSURES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID HT-9 AB A summary is presented of the entire fracture toughness database for HT9 and modified 9Cr-1Mo generated at Hanford. Fracture toughness tests were recently performed on miniature specimens of HT9 and modified 9Cr-1Mo irradiated in the Fast Flux Test Facility (FFTF) to exposures ranging from 35 to about 100 dpa. At test temperatures ranging from 20 to 430-degrees-C, values of toughness and tearing modulus at 35 to 100 dpa were no lower than those obtained previously in tests conducted on specimens irradiated in the Experimental Breeder Reactor-II (EBR-II), despite differences in orientation between the EBR-II and FFTF specimens. The data imply that the fracture toughness of HT9 is adequate to exposures on the order of 100 dpa at temperatures typical of fast reactor operation. Fracture toughness data generated on material irradiated in the High Flux Isotope Reactor, however, demonstrate that both alloys are unsuitable for use even to low neutron exposures at temperatures on the order of 50-degrees-C. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP HUANG, FH (reprint author), WESTINGHOUSE HANFORD CO, POB 1970, RICHLAND, WA 99352 USA. NR 21 TC 16 Z9 16 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAY PY 1992 VL 187 IS 3 BP 278 EP 293 DI 10.1016/0022-3115(92)90508-I PG 16 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA HV687 UT WOS:A1992HV68700013 ER PT J AU BARABASH, VR BARANOV, AG GAHL, J LITUNOVSKY, VL MCDONALD, J OVCHINNIKOV, IB AF BARABASH, VR BARANOV, AG GAHL, J LITUNOVSKY, VL MCDONALD, J OVCHINNIKOV, IB TI EXPERIMENTAL-STUDY OF PULSE PLASMA CARBON MATERIALS INTERACTION DURING THE SIMULATION OF THERMAL QUENCH PHASE OF TOKAMAK PLASMA DISRUPTION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Letter C1 UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP BARABASH, VR (reprint author), DV EFREMOV ELECTROPHYS APPARATUS INST,LENINGRAD,USSR. NR 6 TC 13 Z9 13 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 MAY PY 1992 VL 187 IS 3 BP 298 EP 302 DI 10.1016/0022-3115(92)90510-R PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA HV687 UT WOS:A1992HV68700015 ER PT J AU HAWKINS, RA CHOI, Y HUANG, SC HOH, CK DAHLBOM, M SCHIEPERS, C SATYAMURTHY, N BARRIO, JR PHELPS, ME AF HAWKINS, RA CHOI, Y HUANG, SC HOH, CK DAHLBOM, M SCHIEPERS, C SATYAMURTHY, N BARRIO, JR PHELPS, ME TI EVALUATION OF THE SKELETAL KINETICS OF FLUORINE-18-FLUORIDE ION WITH PET SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article ID BRAIN TRANSFER CONSTANTS; WHOLE-BODY RETENTION; TIME UPTAKE DATA; BLOOD-FLOW; GRAPHICAL EVALUATION; COMPUTED-TOMOGRAPHY; METABOLIC-RATE; BONE; GLUCOSE; F-18 AB To evaluate the feasibility of quantitatively assessing regional skeletal fluoride uptake in humans in focal and generalized bone disease, we investigated the skeletal kinetics of [F-18] fluoride ion with dynamic PET imaging. Dynamic image sets were acquired over a 60-min interval in a multiplane PET device, and input functions (plasma F-18 time-activity curves) were measured directly from arterialized blood and, in some cases, determined from image-derived left ventricular cavity activity measurements. Our results indicate: 1. A steady-state ratio of [F-18]fluoride ion concentration in plasma to whole blood greater than unity (1.23 for plasma to directly assayed whole blood and 1.44 for plasma to left ventricular cavity imaged concentrations. This concentration difference produces a scaling factor that must be considered when using image derived or directly measured input functions. 2. The preferred tracer kinetic model configuration for [F-18]fluoride ion skeletal kinetics is a three compartment model that includes a "bound" and "unbound" bone [F-18]fluoride ion compartment. 3. The rate constant for forward transport of [F-18]fluoride ion from plasma to the extravascular space of bone (K1) and the regional blood volume parameter generate estimates of bone blood flow and vascular volume, respectively, that are in the physiologic range of reported for mammals. Estimates of the uptake constant for fluoride in bone, using nonlinear regression (K(NLR) = 0.0360 +/- 0.0064 ml/min/ml), are in very good agreement with an estimate of the same parameter obtained with Patlak graphical analysis (K(PAT) = 0.0355 +/- 0.0061 ml/min/ml). 4. Generating parametric images of K(PAT) facilitates quantification of regional bone [F-18]fluoride ion kinetics. The method is computationally practical, and, with either the parametric imaging approach or with standard region of interest analysis, can be used to generate quantitative estimates of fluoride uptake (a "bone metabolic index") in focal skeletal regions or in more generalized distributions. C1 UNIV CALIF LOS ANGELES,SCH MED,BIOMED & ENVIRONM SCI,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,SCH MED,CRUMP INST BIOL IMAGING,LOS ANGELES,CA 90024. RP HAWKINS, RA (reprint author), UNIV CALIF LOS ANGELES,SCH MED,DEPT RADIOL SCI,DIV NUCL MED & BIOPHYS,LAB NUCL MED DOE,LOS ANGELES,CA 90024, USA. NR 35 TC 208 Z9 215 U1 0 U2 3 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD MAY PY 1992 VL 33 IS 5 BP 633 EP 642 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA HT117 UT WOS:A1992HT11700005 PM 1569473 ER PT J AU THOMAS, SR STABIN, MG CHEN, CT SAMARATUNGA, RC AF THOMAS, SR STABIN, MG CHEN, CT SAMARATUNGA, RC TI MIRD PAMPHLET NO 14 - A DYNAMIC URINARY-BLADDER MODEL FOR RADIATION-DOSE CALCULATIONS SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article AB The constant-volume urinary bladder model in the standard MIRD phatom has recognized limitations. Various investigators have developed detailed models incorporating more physiologically realistic feature such as expanding bladder contents and residual volume, and variable urinary input rate, initial volume and first void time. We have reviewed these published models and have developed a new model incorporating these factors. The model consists of a spherical source with variable volume to simulate the bladder contents and a wall represented by a spherical shell of constant volume. The wall thickness varies as the source expands or contacts. The model provides for variable urine entry rate (three different hydration states), initial bladder contents volume, residual volume and first void time. The voiding schedule includes an extended nighttime gap during which the urine entry rate is reduced to one-half the daytime rate. Radiation dose estimates have been calculated for the bladder wall surface (including photon and electron components) and at several depths in the wall (electron component) for [F-18]FDG, Tc-99m-DTPA, Tc-99m-HEDP, [Tc-99m-pertechnetate Tc-99m-RBCs, Tc-99m-glucoheptonate, Tc-99m-MAG3, [I-123]/[I-124]/[I-131]OIH and sodium [I-131]iodide(Nal). The initial bladder volume and first void time that provide the lowest radiation dose to the bladder wall are determined separately for each compound to give guidance for establishing dose reduction protocols. C1 UNIV CINCINNATI,COLL MED,DEPT RADIOL,CINCINNATI,OH 45221. OAK RIDGE ASSOCIATED UNIV,OAK RIDGE,TN 37830. UNIV CHICAGO,CHICAGO,IL 60637. SOC NUCL MED,MIRD COMM,NEW YORK,NY. NR 28 TC 30 Z9 30 U1 0 U2 1 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD MAY PY 1992 VL 33 IS 5 BP 783 EP 802 PG 20 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA HT117 UT WOS:A1992HT11700031 PM 1569492 ER PT J AU PAUL, ES CLARK, RM FORBES, SA FOSSAN, DB HUGHES, JR LAFOSSE, DR LIANG, Y MA, R NOLAN, PJ REGAN, PH VASKA, P WADSWORTH, R WARING, MP AF PAUL, ES CLARK, RM FORBES, SA FOSSAN, DB HUGHES, JR LAFOSSE, DR LIANG, Y MA, R NOLAN, PJ REGAN, PH VASKA, P WADSWORTH, R WARING, MP TI COLLECTIVE AND NONCOLLECTIVE HIGH-SPIN STATES IN I-115 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article ID ROTATIONAL BANDS; SHAPE CHANGES; NUCLEI AB The Mo-92(Al-27, 2p2n-gamma) reaction has been used to populate high-spin states in 115I. The dominant structures are associated with pi-h11/2[550]1/2- and pi-g9/2[404]9/2+ orbitals. At the highest spins, favoured states with I(pi) = 43/2- and 51/2-, associated with non-collective oblate configurations, are yrast. The systematics of such states in the odd-A 115I-I-121 isotopes are discussed. C1 UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. RP PAUL, ES (reprint author), UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BX,ENGLAND. NR 25 TC 49 Z9 49 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD MAY PY 1992 VL 18 IS 5 BP 837 EP 846 DI 10.1088/0954-3899/18/5/012 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA HU144 UT WOS:A1992HU14400012 ER PT J AU CAI, Y CHEN, SS CHANDRA, S AF CAI, Y CHEN, SS CHANDRA, S TI A THEORY FOR FLUIDELASTIC INSTABILITY OF TUBE-SUPPORT-PLATE-INACTIVE MODES SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID STABILITY AB Fluidelastic instability of loosely supported tubes, vibrating in a tube support plate (TSP)-inactive mode, is suspected to be one of the main causes of tube failure in some operating steam generators and heat exchangers. This paper presents a mathematical model for fluidelastic instability of loosely supported tubes exposed to nonuniform cross flow. The model incorporates all motion-dependent fluid forces based on the unsteady-flow theory. In the unstable region associated with a TSP-inactive mode, tube motion can be described by two linear models: TSP-inactive mode when tubes do not strike the TSP, and TSP-active mode when tubes do strike the TSP. The bilinear model (consisting of these linear models) presented here simulates the characteristics of fluidelastic instability of loosely supported tubes in stable and unstable regions associated with TSP-inactive modes. Analytical results obtained with the model are compared with published experimental data; they agree reasonably well. The prediction procedure presented for the fluidelastic instability response of loosely supported tubes is applicable to the stable and unstable regions of the TSP-inactive mode. C1 NE UTILITIES SERV CO,HARTFORD,CT. RP CAI, Y (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 25 TC 3 Z9 3 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD MAY PY 1992 VL 114 IS 2 BP 139 EP 148 DI 10.1115/1.2929021 PG 10 WC Engineering, Mechanical SC Engineering GA HW210 UT WOS:A1992HW21000002 ER PT J AU AINSWORTH, RA RUGGLES, MB TAKAHASHI, Y AF AINSWORTH, RA RUGGLES, MB TAKAHASHI, Y TI FLAW ASSESSMENT PROCEDURE FOR HIGH-TEMPERATURE REACTOR COMPONENTS SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article AB An interim high-temperature flaw assessment procedure is described. This is a result of a collaborative effort between Electric Power Research Institute in the US, Central Research Institute of Electric Power Industry in Japan, and Nuclear Electric plc in the UK. The procedure addresses pre-existing defects subject to creep-fatigue loading conditions. Laws employed to calculate the crack growth per cycle are defined in terms of fracture mechanics parameters and constants related to the component material. The crack growth laws may be integrated to calculate the remaining life of a component or to predict the amount of crack extension in a given period. Fatigue and creep crack growth per cycle are calculated separately, and the total crack extension is taken as the simple sum of the two contributions. An interaction between the two propagation modes is accounted for in the material properties in the separate calculations. In producing the procedure, limitations of the approach have been identified. Some of these limitations are to be addressed in an extension of the current collaborative program. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. CENT RES INST ELECT POWER IND,KOMAE RES LAB,TOKYO,JAPAN. RP AINSWORTH, RA (reprint author), NUCL ELECT PLC,BERKELEY NUCL LABS,BERKELEY,GLOS,ENGLAND. RI Ruggles-Wrenn, Marina/J-6103-2014; OI Ainsworth, Robert/0000-0001-9635-461X NR 18 TC 14 Z9 14 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD MAY PY 1992 VL 114 IS 2 BP 166 EP 170 DI 10.1115/1.2929024 PG 5 WC Engineering, Mechanical SC Engineering GA HW210 UT WOS:A1992HW21000005 ER PT J AU MAIYA, PS PAI, BK AF MAIYA, PS PAI, BK TI MODELING OF NOTCH EFFECTS ON STRESS-CORROSION CRACKING SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID STAINLESS-STEEL; TEMPERATURE; WATER AB The intergranular stress corrosion cracking (IGSCC) of sensitized Type 304 stainless steel (SS) has been investigated by slow strain rate tests (SSRTs) in 289-degrees-C water containing sulfate impurity. Both smooth and circumferentially notched specimens were used to assess the effects of strain concentrations on stress corrosion cracking (SCC). Experiments were conducted over a range of nominal strain rates of 10(-5) to 10(-7) s-1. A comparison of the results observed for the smooth and notched specimens suggests that the estimated growth rates of small cracks in SSRT specimen geometry is influenced by the presence of strain concentrations. In particular, the average crack growth rates estimated from tests performed at the same nominal strain rate are observed to increase with the notch depth, and power-law relationships exist between strain rate and SCC parameters such as failure time and crack growth rate. The strain concentration factors at the notch roots of Type 304 specimens subjected to axial load have been estimated by finite-element elastic-plastic stress analyses, as well as by Neuber's rule. The nominal and crack-tip strain rate effects on SCC in both smooth and notched specimens are interpreted in terms of a model based on elastic-plastic fracture mechanics and film-rupture mechanisms that invoke diffusion-controlled SCC growth kinetics. C1 PURDUE UNIV CALUMET,DEPT ENGN,HAMMOND,IN 46323. RP MAIYA, PS (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD MAY PY 1992 VL 114 IS 2 BP 171 EP 177 DI 10.1115/1.2929025 PG 7 WC Engineering, Mechanical SC Engineering GA HW210 UT WOS:A1992HW21000006 ER PT J AU RABERN, DA LEWIS, MW AF RABERN, DA LEWIS, MW TI 2-DIMENSIONAL AND 3-DIMENSIONAL SIMULATIONS OF MOVING PRESSURE FRONTS IN GUN TUBES SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article AB Options were added to the PRONTO2D and PRONTO3D structural dynamics finite element codes to include the effect of a traveling pressure front that follows a projectile while transiting pressurizing axisymmetric and nonstraight gun tubes. Pressure varied in magnitude and location with time and projectile displacement to predict the dynamic structural response of the projectile and gun tube. Two and three-dimensional simulations were performed to study the effect of this pressure front and its influence on projectile gun tube interaction and lateral movement of the projectile in the gun tube caused by variation of the gun centerline during projectile launch and recoil. Discussions of theory, implementation, and results from simulations are presented. RP RABERN, DA (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 14 TC 0 Z9 0 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD MAY PY 1992 VL 114 IS 2 BP 181 EP 188 DI 10.1115/1.2929027 PG 8 WC Engineering, Mechanical SC Engineering GA HW210 UT WOS:A1992HW21000008 ER PT J AU DELCUL, GD NAVE, SE BEGUN, GM PETERSON, JR AF DELCUL, GD NAVE, SE BEGUN, GM PETERSON, JR TI RAMAN-SPECTRA OF TETRAGONAL LANTHANIDE OXYCHLORIDES OBTAINED FROM POLYCRYSTALLINE AND SINGLE-CRYSTAL SAMPLES SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article AB The reported Raman spectra of the tetragonal [lead chlorofluoride-type structure, D4h7-P4/nmm (ITC No. 129)] lanthanide oxychlorides are inconsistent. Nuclear site symmetry analysis predicts six Raman bands. Five peaks are consistently observed, whereas the sixth remains controversial. Also, two different sets of irreducible representations are reported: 2A1g + 3E(g) + B2g (or B1g) + 3A2u + 3E(u) which include the three acoustic modes, A2u{T(z)} and E(u){T(x), T(y)}. The present analysis of the polarized Raman spectra from PrOCl and NdOCl single crystals clearly showed that the correct irreducible representation contains the B2g symmetry. The symmetries of three Raman-active bands are well determined, a fourth band displays two polarizations and a fifth band has no clear polarization and is assigned E(g) by default. The EuOCl Raman spectrum exhibits a weak electronic Raman band which originates in electron-phonon coupling as a result of the closeness between the vibrational and electronic eigenvalues. The low-energy band (LaOCl, 67 cm-1; EuOCl, 70 cm-1; and GdOCl, 65 cm-1) and the high-energy band (525 cm-1 for LaOCl) reported by others for selected lanthanide oxychlorides were not observed in the present work. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. DEPT CHEM,DIV TECH,OAK RIDGE,TN 37831. SAVANNAH RIVER ECOL LAB,ANALYT DEV SECT,AIKEN,SC 29802. OAK RIDGE NATL LAB,DIV CHEM,TRANSURANIUM RES LAB,OAK RIDGE,TN 37831. NR 27 TC 7 Z9 7 U1 4 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD MAY PY 1992 VL 23 IS 5 BP 267 EP 272 DI 10.1002/jrs.1250230505 PG 6 WC Spectroscopy SC Spectroscopy GA HY090 UT WOS:A1992HY09000004 ER PT J AU NARAYANAN, VA BEGUN, GM STOKES, DL SUTHERLAND, WS VO-DINH, T AF NARAYANAN, VA BEGUN, GM STOKES, DL SUTHERLAND, WS VO-DINH, T TI NORMAL RAMAN AND SURFACE-ENHANCED RAMAN-SCATTERING (SERS) SPECTRA OF SOME FUNGICIDES AND RELATED CHEMICAL-COMPOUNDS SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID SILVER ELECTRODE AB Surface-enhanced Raman scattering (SERS) spectra of Thiram (C6H12N2S4) and Ferbam (C9H18N3S6Fe); and normal Raman scattering (NRS) spectra of Thiram and Meta-sodium (C2H4NNaS2) were investigated. The SERS spectra of the two compounds and NRS spectrum of Metam-Sodium were recorded for the first time. The SERS signals useful for trace analysis of these fungicides are identified. The spectral features of these compounds are discussed and compared with the previous data. The importance of SERS analyses to ensure the environmentally safe use of such compounds is discussed. RP VO-DINH, T (reprint author), OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, OAK RIDGE, TN 37831 USA. NR 15 TC 23 Z9 23 U1 1 U2 9 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD MAY PY 1992 VL 23 IS 5 BP 281 EP 286 DI 10.1002/jrs.1250230507 PG 6 WC Spectroscopy SC Spectroscopy GA HY090 UT WOS:A1992HY09000006 ER PT J AU MACEK, RW HACKETT, RM AF MACEK, RW HACKETT, RM TI VISCOELASTIC ANALYSIS OF FILAMENT-WOUND COMPOSITE-MATERIAL SYSTEMS SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article AB A methodology for the viscoelastic analysis of filament-wound polymer matrix composites is developed and demonstrated. The procedure uses the elastic-viscoelastic correspondence principle with standard micromechanics models to obtain the viscoelastic properties of the composite. For global analysis, an efficient time-stepping algorithm is developed and implemented in a general purpose finite element code via a user-supplied material subroutine. The algorithm is verified by comparison to the exact analysis of a rigid inclusion in an infinite viscoelastic plate and the utility of the entire methodology is shown by analysis and testing of a composite spring. C1 UNIV MISSISSIPPI,DEPT CIVIL ENGN,UNIVERSITY,MS 38677. RP MACEK, RW (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PD MAY PY 1992 VL 11 IS 5 BP 567 EP 581 DI 10.1177/073168449201100506 PG 15 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA HW503 UT WOS:A1992HW50300006 ER PT J AU HOGAN, RE SKOCYPEC, RD AF HOGAN, RE SKOCYPEC, RD TI ANALYSIS OF CATALYTICALLY ENHANCED SOLAR ABSORPTION CHEMICAL REACTORS .1. BASIC CONCEPTS AND NUMERICAL-MODEL DESCRIPTION SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID HEAT-TRANSFER AB A detailed numerical model is presented for high-temperature, catalytically enhanced, solar absorption chemical reactors. In these reactors, concentrated solar energy is volumetrically absorbed throughout a porous absorber matrix impregnated with a catalyst. The catalyst promotes heterogeneous reactions with fluid-phase reactant species flowing through the absorber. This paper presents a description of a numerical model and the basic concepts of reactor operation. The numerical model of the absorber includes solar and infrared radiation, heterogeneous chemical reactions, conduction in the solid phase, and convection between the fluid and solid phases. The model is nonlinear primarily due to both the radiative transfer and the heterogeneous chemistry occurring in the absorber. The nonlinear two-point boundary value problem is solved using superposition with orthonormalization and an adaptive solution point scheme. This technique preserves accuracy throughout the domain. The model can be modified for other chemical reactions and can be simplified to model volumetric air-heating receivers. RP HOGAN, RE (reprint author), SANDIA NATL LABS,DEPT FLUID & THERMAL SCI,ALBUQUERQUE,NM 87185, USA. NR 17 TC 7 Z9 7 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD MAY PY 1992 VL 114 IS 2 BP 106 EP 111 DI 10.1115/1.2929987 PG 6 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA HW213 UT WOS:A1992HW21300005 ER PT J AU SKOCYPEC, RD HOGAN, RE AF SKOCYPEC, RD HOGAN, RE TI ANALYSIS OF CATALYTICALLY ENHANCED SOLAR ABSORPTION CHEMICAL REACTORS .2. PREDICTED CHARACTERISTICS OF A 100KW CHEMICAL REACTOR SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID HEAT-TRANSFER AB The CAtalytically Enhanced Solar Absorption Receiver (CAESAR) is a 100 kW(chemical) test reactor currently in operation. This type of high-temperature chemical reactor volumetrically absorbs concentrated solar energy throughout a catalytic porous absorber matrix volume, promoting heterogeneous reactions with fluid-phase reactant species flowing through the absorber. A numerical model of these reactors has been developed to provide guidance in the catalytic matrix design for CAESAR. In the CAESAR reactor, methane is reformed using carbon dioxide and a rhodium catalyst. In addition, the model is being used to evaluate both the reactor performance and test data. This paper presents the thermal and chemical characteristics of the reactor for varying incident solar flux, fluid mass flow, convective heat-transfer coefficient, solar and infrared extinction coefficients, and catalyst loading. Predicted CAESAR performance is based on a prototype absorber and anticipated operating conditions. Model results suggest the mass flux must be proportioned to the incident solar flux radial distribution to prevent unacceptably high local temperatures and to provide a reactor having more uniform exit conditions. Either the catalytic loading or geometric thickness of the absorber should be increased for conversion to approach equilibrium levels. Also, the optical density of the matrix (particularly at the sunlit side of the reactor) should be decreased to distribute solar energy more uniformly in depth and decrease matrix temperatures at the front of the absorber. RP SKOCYPEC, RD (reprint author), SANDIA NATL LABS,DEPT FLUID & THERMAL SCI,ALBUQUERQUE,NM 87185, USA. NR 9 TC 7 Z9 7 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD MAY PY 1992 VL 114 IS 2 BP 112 EP 118 DI 10.1115/1.2929988 PG 7 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA HW213 UT WOS:A1992HW21300006 ER PT J AU BUTTERFIELD, CP SCOTT, G MUSIAL, W AF BUTTERFIELD, CP SCOTT, G MUSIAL, W TI COMPARISON OF WIND-TUNNEL AIRFOIL PERFORMANCE DATA WITH WIND TURBINE BLADE DATA SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Horizontal axis wind turbine (HAWT) performance is usually predicted by using wind tunnel airfoil performance data in a blade element momentum theory analysis. This analysis assumes that the rotating blade airfoils will perform as they do in the wind tunnel. However, when stall-regulated HAWT performance is measured in full-scale operation, it is common to find that peak power levels are significantly greater than those predicted. Pitch-controlled rotors experience predictable peak power levels because they do not rely on stall to regulate peak power. This has led to empirical corrections to the stall predictions. Viterna and Corrigan ( 1981) proposed the most popular version of this correction. But very little insight has been gained into the basic cause of this discrepancy. The National Renewable Energy Laboratory (NREL), funded by the DOE, has conducted the first phase of an experiment which is focused on understanding the basic fluid mechanics of HAWT aerodynamics. Results to date have shown that unsteady aerodynamics exist during all operating conditions and dynamic stall can exist for high yaw angle operation. Stall hysteresis occurs for even small yaw angles and delayed stall is a very persistent reality in all operating conditions. Delayed stall is indicated by a leading edge suction peak which remains attached through angles of attack (AOA) up to 30 degrees. Wind tunnel results show this peak separating from the leading edge at 18 deg AOA. The effect of this anomaly is to raise normal force coefficients and tangent force coefficients for high AOA. Increased tangent forces will directly affect HAWT performance in high wind speed operation. This report describes pressure distribution data resulting from both wind tunnel and HAWT tests. A method of bins is used to average the HAWT data which is compared to the wind tunnel data. The analysis technique and the test set-up for each test are described. RP BUTTERFIELD, CP (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 10 TC 5 Z9 7 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD MAY PY 1992 VL 114 IS 2 BP 119 EP 124 DI 10.1115/1.2929989 PG 6 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA HW213 UT WOS:A1992HW21300007 ER PT J AU SMITH, MG GOODENOUGH, JB MANTHIRAM, A TAYLOR, RD PENG, WM KIMBALL, CW AF SMITH, MG GOODENOUGH, JB MANTHIRAM, A TAYLOR, RD PENG, WM KIMBALL, CW TI TIN AND ANTIMONY VALENCE STATES IN BASN0.85SB0.15O3-DELTA SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID SUPERCONDUCTIVITY; BAPB1-XBIXO3; BASN1-XSBXO3 C1 UNIV CALIF LOS ALAMOS SCI LAB,DEPT PHYS,LOS ALAMOS,NM 87545. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. RP SMITH, MG (reprint author), UNIV TEXAS,CTR MAT SCI & ENGN,ETC 5 160,AUSTIN,TX 78712, USA. NR 6 TC 45 Z9 47 U1 0 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAY PY 1992 VL 98 IS 1 BP 181 EP 186 DI 10.1016/0022-4596(92)90084-9 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA HR916 UT WOS:A1992HR91600020 ER PT J AU MILLER, DG SARTORIO, R PADUANO, L AF MILLER, DG SARTORIO, R PADUANO, L TI AN EXTRAPOLATION PROCEDURE TO OBTAIN THE TOTAL FRINGE NUMBER FROM GOUY FRINGE PATTERN DATA SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE LIQUID DIFFUSION; OPTICAL METHODS; GOUY FRINGES; FRINGE PATTERN ANALYSIS; EXTRAPOLATION OF FRINGE DATA; TOTAL NUMBER OF FRINGES; RAFFINOSE-KCL-H2O; SUCROSE-H2O; SRCL2-H2O ID SYSTEMS AB A rapid new procedure is described for getting the total number of fringes J from Gouy fringe pattern data. This PQ method is exact and the results excellent (within 0.01 - 0.03 fringe) for ideal systems (OMEGA(j) = 0 for all j, Q0 = 0). such systems include most binaries; for these, the diffusion coefficient is either constant or a polynomial function of concentration with small concentration differences. For multicomponent systems and some binaries, Q0 can be significantly different from 0. In these cases, the PQ method unambiguously gives the integer number of fringes. If in addition Q0/Q1 is larger than 2.0, then J obtained from a second extrapolation procedure is also good. C1 UNIV FEDERICO NAPOLI 2,DIPARTIMENTO CHIM,I-80134 NAPLES,ITALY. RP MILLER, DG (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. OI PADUANO, Luigi/0000-0002-1105-4237 NR 24 TC 17 Z9 17 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD MAY PY 1992 VL 21 IS 5 BP 459 EP 476 DI 10.1007/BF00649699 PG 18 WC Chemistry, Physical SC Chemistry GA HT296 UT WOS:A1992HT29600005 ER PT J AU SRINIVASAN, R DAVIS, BH CAVIN, OB HUBBARD, CR AF SRINIVASAN, R DAVIS, BH CAVIN, OB HUBBARD, CR TI CRYSTALLIZATION AND PHASE-TRANSFORMATION PROCESS IN ZIRCONIA - AN INSITU HIGH-TEMPERATURE X-RAY-DIFFRACTION STUDY SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article DE ZIRCONIA; PHASE TRANSFORMATIONS; CRYSTALLIZATION; PRECIPITATION; X-RAY DIFFRACTION ID POLYCRYSTALLINE ZIRCONIA; TETRAGONAL PHASE; CRYSTAL PHASE; ZRO2; STABILIZATION; OXIDE; PH AB Amorphous zirconia precursors were made by the precipitation of a zirconium tetrachloride solution with either slow (8 h) or rapid additions of ammonium hydroxide at a pH of 10.5. Following calcination at 500-degrees-C for 4 h, the rapidly precipitated precursor exhibited predominantly monoclinic ZrO2 phase, while the slowly precipitated precursor produced the tetragonal ZrO2 phase. The crystallization and phase transformations were followed by in situ high-temperature X-ray diffraction (HTXRD) for both specimens in helium and in air. Each amorphous precursor first crystallizes as the tetragonal phase at about 450-degrees-C. A tetragonal-to-monoclinic phase transformation of the rapidly precipitated material was observed on cooling at about 275-degrees-C. Surface impregnation of sulfate ions following precipitation inhibited the tetragonal-to-monoclinic transformation for the rapidly precipitated ZrO2 sample. The crystallite size for the t-ZrO2 of all samples, irrespective of whether they transform to monoclinic, was approximately 11 nm, indicating that the t --> m transformation in these materials is not controlled by differences in crystallite size. It is therefore suggested that anionic vacancies control the tetragonal-to-monoclinic phase transformation on cooling, and that oxygen adsorption triggers this phase transformation. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831. RP SRINIVASAN, R (reprint author), UNIV KENTUCKY,CTR APPL ENERGY RES,LEXINGTON,KY 40511, USA. NR 36 TC 79 Z9 79 U1 5 U2 14 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1992 VL 75 IS 5 BP 1217 EP 1222 DI 10.1111/j.1151-2916.1992.tb05560.x PG 6 WC Materials Science, Ceramics SC Materials Science GA HU733 UT WOS:A1992HU73300025 ER PT J AU NAGY, Z WESSON, JM AF NAGY, Z WESSON, JM TI ERROR ANALYSIS OF THE POLARIZATION-RESISTANCE TECHNIQUE FOR CORROSION-RATE MEASUREMENTS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB The polarization-resistance measurement is a simple and rather popular technique for the determination of corrosion rates from electrochemical measurements, and the characteristics and limitations of this technique have been discussed in many publications. In this work, the error caused by the neglect of mass transport is examined, since this limitation, somewhat surprisingly, has not been considered earlier. It can be shown that, for the idealized polarization-resistance technique (i.e., when the slope of the polarization curve is taken at DELTA-E = 0), the percent error in the corrosion current density due to the neglect of mass transport is: - 100 (b(a)/b(c) . i(corr)/i(l)) (1 + b(a)/b(c))-1. The error increases with increasing i(corr)/i(l) and with increasing b(a)/b(c); the error is always negative, and, in extreme cases, it can be very large. This is a dangerous situation because the true corrosion rate can be much larger than the calculated rate. However, for small values of b(a)/b(c), which is often the case for practical corrosion reactions, the error can be negligible. For the practical polarization-resistance technique (i.e., when the slope of the polarization curve is measured with a finite DELTA-E value), the error due to the neglect of mass transport and the linearization error are combined. However, these errors are not simply additive because the linearization error itself is a function of the extent of the mass transport. The effect of several variables is discussed. The opportunity is also taken to reevaluate some other limitations of the polarization-resistance technique, namely, the errors caused by (i) linearization of the current potential equation, (ii) incorrect estimates of the Tafel slopes, (iii) neglect of reverse partial-reactions, and (iv) neglect of uncompensated solution resistance. These limitations have been discussed before, but our representations are more generalized, especially in that the effect of all pertinent variables is expressed in one single graph. C1 ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439. RP NAGY, Z (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 18 TC 4 Z9 4 U1 0 U2 1 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1992 VL 139 IS 5 BP 1261 EP 1266 DI 10.1149/1.2069394 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA HU228 UT WOS:A1992HU22800014 ER PT J AU MUELLER, A WANG, G RAPP, RA COURTRIGHT, EL AF MUELLER, A WANG, G RAPP, RA COURTRIGHT, EL TI DEPOSITION AND CYCLIC OXIDATION BEHAVIOR OF A PROTECTIVE (MO,W)(SI,GE)2 COATING ON NB-BASE ALLOYS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB A multicomponent diffusion coating has been developed to protect Nb-base alloys from high-temperature environmental attack. A solid solution of molybdenum and tungsten disilicide, (Mo,W)Si2, constituted the primary coating layer which supported a slow-growing protective silica scale in service. Germanium additions were made during the coating process to improve the cyclic oxidation resistance by increasing the thermal expansion coefficient of the vitreous silica film formed and to avoid pesting by decreasing the viscosity of the protective film. The development of the halide-activated pack cementation coating process to produce this (Mo,W)(Si,Ge)2 coating on Nb-base alloys is described. The results of cyclic oxidation for coupons coated under different conditions in air at 1370-degrees-C are presented. Many coupons have successfully passed 200 1 h cyclic oxidation tests at 1370-degrees-C with weight-gain values in the range of 1.2 to 1.6 mg/cm2. C1 OHIO STATE UNIV, DEPT MAT SCI & ENGN, COLUMBUS, OH 43210 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 25 TC 52 Z9 52 U1 4 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1992 VL 139 IS 5 BP 1266 EP 1275 DI 10.1149/1.2069395 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA HU228 UT WOS:A1992HU22800015 ER PT J AU BREVETT, CAS JOHNSON, DC AF BREVETT, CAS JOHNSON, DC TI ANODIC OXIDATIONS OF SULFITE, THIOSULFATE, AND DITHIONITE AT DOPED PBO2-FILM ELECTRODES SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB The anodic oxidations of SO32-, S2O32-, and S2O42- Were examined at pure and doped PbO2-film electrodes at 25 and 65-degrees-C in a NaHCO3/Na2CO3 buffer (pH 10). Values of half-wave potentials (E1/2) vary only slightly with the identity of dopant. The numbers of electrons transferred in the electrochemical processes (n, eq mol-1), as determined by coulometry and hydrodynamic amperometry, are consistently less than expected for complete oxidation to sulfate (SO42-). Estimated values of heterogeneous rate constants and reaction orders are also compared. Results of wet-chemical analyses are interpreted to indicate that some dithionate (S2O62-) is formed during the anodic reactions. A possible mechanistic scheme based on anodic transfer of oxygen is considered. C1 DEPT CHEM,AMES,IA 50011. AMES LAB,AMES,IA 50011. NR 12 TC 30 Z9 30 U1 0 U2 0 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1992 VL 139 IS 5 BP 1314 EP 1319 DI 10.1149/1.2069403 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA HU228 UT WOS:A1992HU22800023 ER PT J AU FULLER, TF NEWMAN, J AF FULLER, TF NEWMAN, J TI EXPERIMENTAL-DETERMINATION OF THE TRANSPORT NUMBER OF WATER IN NAFION-117 MEMBRANE SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB The transport number of water in Nafion (R) 117 membrane over a wide range of water contents is determined experimentally using a concentration cell. The transport number of water, the ratio t(o)m/z(o), is about 1.4 for a membrane equilibrated with saturated water vapor at 25-degrees-C, decreases slowly as the membrane is dehydrated, and falls sharply toward zero as the concentration of water approaches zero. The relationship between the transference number, the transport number, and the electro-osmotic drag coefficient is presented, and their relevance to water management in solid-polymer-electrolyte fuel cells is discussed. Results are compared with other data available in the literature and with the theoretical maximum. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. RP FULLER, TF (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Newman, John/B-8650-2008 OI Newman, John/0000-0002-9267-4525 NR 15 TC 211 Z9 222 U1 2 U2 23 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1992 VL 139 IS 5 BP 1332 EP 1337 DI 10.1149/1.2069407 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA HU228 UT WOS:A1992HU22800026 ER PT J AU KUMAR, BVKV DICKEY, FM DELAURENTIS, JM AF KUMAR, BVKV DICKEY, FM DELAURENTIS, JM TI CORRELATION FILTERS MINIMIZING PEAK LOCATION ERRORS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article AB A new measure, termed the peak location error (PLE), is introduced to characterize the ability of a correlation filter to locate a target in the input. It is shown that the filter minimizing the PLE is the classical matched filter. Comparison is made between the minimal PLE and the error achievable with phase-only filters. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP KUMAR, BVKV (reprint author), CARNEGIE MELLON UNIV,PITTSBURGH,PA 15213, USA. NR 11 TC 21 Z9 21 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD MAY PY 1992 VL 9 IS 5 BP 678 EP 682 DI 10.1364/JOSAA.9.000678 PG 5 WC Optics SC Optics GA HQ478 UT WOS:A1992HQ47800005 ER PT J AU MOERNER, WE SMALL, GJ AF MOERNER, WE SMALL, GJ TI PERSISTENT SPECTRAL HOLE BURNING - INTRODUCTION SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Editorial Material C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP MOERNER, WE (reprint author), IBM CORP,DIV RES,ALMADEN RES CTR,650 HARRY RD,SAN JOSE,CA 95120, USA. RI Moerner, William/C-3260-2008 OI Moerner, William/0000-0002-2830-209X NR 0 TC 1 Z9 1 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 712 EP 712 PG 1 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400009 ER PT J AU SHU, LC SMALL, GJ AF SHU, LC SMALL, GJ TI MECHANISM OF NONPHOTOCHEMICAL HOLE BURNING - CRESYL VIOLET IN POLYVINYL-ALCOHOL FILMS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL MEETING ON PERSISTENT SPECTRAL HOLE-BURNING SCIENCE AND APPLICATIONS CY SEP 26-28, 1991 CL MONTEREY, CA SP OPT SOC AMER ID DOPED MTHF GLASS; LOW-TEMPERATURE GLASSES; AMORPHOUS SOLIDS; ORGANIC GLASSES; OPTICAL LINEWIDTHS; SPECTRAL HOLES; KINETICS; RELAXATION; TETRACENE; DYNAMICS AB Polarized nonphotochemical hole-burned spectra of Cresyl Violet in polyvinyl alcohol films are presented for various burn temperatures (T(B)). For T(B) = 15 K, but not for T(B) = 2.2 K, a significant rotation of Cresyl Violet is indicated. The broad, tailing antihole is observed to depend on T(B). The quantum efficiency distributions for the zero-phonon hole and pseudo-phonon sideband are quite similar, proving that the phonons created by excitation of the phonon sideband are not important for hole burning. The quantum efficiency is independent of T(B) over the range studied, 1.6-15 K. Over this range essentially 100% of the zero-phonon lines can be burned. The results show that the standard two-level-system (extrinsic) model for nonphotochemical hole burning is inadequate. The results are discussed in terms of an outside-in hierarchy of configurational relaxation events model [Chem. Phys. 141, 447 (1990)] as well as other models. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP SHU, LC (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 46 TC 64 Z9 65 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 724 EP 732 DI 10.1364/JOSAB.9.000724 PG 9 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400012 ER PT J AU SHU, LC SMALL, GJ AF SHU, LC SMALL, GJ TI DISPERSIVE KINETICS OF NONPHOTOCHEMICAL HOLE BURNING AND SPONTANEOUS HOLE FILLING - CRESYL VIOLET IN POLYVINYL FILMS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL MEETING ON PERSISTENT SPECTRAL HOLE-BURNING SCIENCE AND APPLICATIONS CY SEP 26-28, 1991 CL MONTEREY, CA SP OPT SOC AMER ID AMORPHOUS SOLIDS; 2-LEVEL SYSTEMS; RELAXATION DYNAMICS; LOW-TEMPERATURES; ORGANIC GLASSES; TRANSITIONS; DENSITY; GROWTH; STATES; DECAY AB The dispersive kinetics of nonphotochemical burning and spontaneous filling of the zero-phonon hole of Cresyl Violet in polyvinyl alcohol at 1.6 K are analyzed in terms of the standard external two-level system (TLS(ezt)) model for probe-glass systems and a distribution function for the tunnel frequency derived from a normal distribution function for the tunnel parameter-lambda. Average values for the relaxation rates for burning and filling are determined. It is shown that the dominant mechanism for filling is not global spectral diffusion but rather antihole reversion. A high degree of positive correlation between the rates of burning and filling associated with the TLS(ext) is found. A new methodology that permits a more physically reasonable interpretation of spontaneous hole-filling kinetics is described. It is based on the hypothesis that only a fraction of burned sites, on reversion to the ground state, yield sites with resonance frequencies that lie within the hole profile. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP SHU, LC (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 29 TC 28 Z9 28 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 733 EP 737 DI 10.1364/JOSAB.9.000733 PG 5 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400013 ER PT J AU SHU, LC SMALL, GJ AF SHU, LC SMALL, GJ TI LASER-INDUCED HOLE FILLING - CRESYL VIOLET IN POLYVINYL-ALCOHOL FILMS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL MEETING ON PERSISTENT SPECTRAL HOLE-BURNING SCIENCE AND APPLICATIONS CY SEP 26-28, 1991 CL MONTEREY, CA SP OPT SOC AMER ID RARE-EARTH IONS; SPECTRAL DIFFUSION; AMORPHOUS SOLIDS; ORGANIC GLASSES; PHOTOSYSTEM-I; TRANSITIONS; LINEWIDTHS AB Laser-induced hole filling results are reported for the case in which the primary burn frequency, omega(B), and the secondary (filling) frequency, omega(S), lie in the origin absorption band of Cresyl Violet. Both two-laser and one-laser (with a Fourier-transform spectrometer) experiments were performed. The one-laser experiments permit monitoring of the entire hole spectrum, which consists of the zero-phonon hole at omega(B), its companion phonon sideband holes, and the blue-shifted antihole. From the dependence of the filling efficiency on omega(B) - omega(S) it is concluded that the dominant mechanism involves electronic excitation of the antihole sites by means of their broad phonon sideband. It is shown that the antihole sites retain at least a partial memory of their preburn configurations. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP SHU, LC (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 22 TC 30 Z9 31 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 738 EP 745 DI 10.1364/JOSAB.9.000738 PG 8 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400014 ER PT J AU AMBROSE, WP SIEVERS, AJ AF AMBROSE, WP SIEVERS, AJ TI PERSISTENT INFRARED SPECTRAL HOLE BURNING OF NO2- AND NO3- IONS IN POTASSIUM-IODIDE .2. SPECTRAL CHANGES FAR FROM THE BURN FREQUENCY SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL MEETING ON PERSISTENT SPECTRAL HOLE-BURNING SCIENCE AND APPLICATIONS CY SEP 26-28, 1991 CL MONTEREY, CA SP OPT SOC AMER ID KI SINGLE-CRYSTALS; ALKALI-HALIDES; RAMAN; MOLECULES; MODES; KBR; CN AB We combine persistent IR spectral hole burning with high-resolution Fourier-transform interferometry to observe IR spectral changes far from the laser burn frequency for NO2- and NO3- ions in KI single crystals. Three separate vibrational mode types are investigated, and information about the symmetries of the modes is obtained. First the technique is used to separate isotopically modified and mixed stretch modes. Isotope-dependent complex structures in the NO2-nu-1- and [nu-1 + nu-3]-mode regions appear to arise because of resonances between nu-1 and [nu-3 + phonon sideband] modes. Phonon-gap-mode sidebands on the NO2-nu-3 mode are examined and compared with results from far-infrared and Raman scattering studies. The number of resolved KI:NO2- gap modes is increased to five, and the translational and librational character of these modes is discussed in terms of their symmetry assignments. Defect-cluster lines of NO2- are hole burned, and many related satellite lines are observed to change. New assignments for NO2-:NO2- defect pairs and lines belonging to single NO2- defects associated with near-neighbor alkali or halide defects are made. Satellite lines of NO3- are also found to hole burn, and changes in these modes produce changes in additional NO2- satellite lines. Hence defect clusters involving both NO2- and NO3- ions are identified also. C1 CORNELL UNIV,ATOM & SOLID STATE PHYS LAB,ITHACA,NY 14853. CORNELL UNIV,CTR MAT SCI,ITHACA,NY 14853. RP AMBROSE, WP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 20 TC 2 Z9 2 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 753 EP 762 DI 10.1364/JOSAB.9.000753 PG 10 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400016 ER PT J AU ARNOLD, S COMUNALE, J WHITTEN, WB RAMSEY, JM FULLER, KA AF ARNOLD, S COMUNALE, J WHITTEN, WB RAMSEY, JM FULLER, KA TI ROOM-TEMPERATURE MICROPARTICLE-BASED PERSISTENT HOLE-BURNING SPECTROSCOPY SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL MEETING ON PERSISTENT SPECTRAL HOLE-BURNING SCIENCE AND APPLICATIONS CY SEP 26-28, 1991 CL MONTEREY, CA SP OPT SOC AMER ID ENHANCED ENERGY-TRANSFER; AEROSOL-PARTICLE; PHOTON LIFETIME; RESONANCES AB We present an analytical model for hole burning in a random collection of microparticles, based on single-particle properties. The model indicates that the linewidth of the central hole is approximately Lorentzian in shape and is controlled by the photon lifetimes in individual particles. Our conclusion is consistent with experiments on a two-dimensional layer of connected microparticles. Electrodynamic calculations for a pair of particles in contact provide an explanation for the apparent lack of importance of interparticle interactions in the experiments and suggest conditions under which the effects of such interactions should appear. C1 OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. RP ARNOLD, S (reprint author), POLYTECH INST NEW YORK,DEPT PHYS,MICROPARTICLE PHOTOPHYS LAB,333 JAY ST,BROOKLYN,NY 11201, USA. NR 12 TC 29 Z9 30 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1992 VL 9 IS 5 BP 819 EP 824 DI 10.1364/JOSAB.9.000819 PG 6 WC Optics SC Optics GA HT834 UT WOS:A1992HT83400028 ER PT J AU MITSUDA, S GEHRING, PM SHIRANE, G YOSHIZAWA, H ONUKI, Y AF MITSUDA, S GEHRING, PM SHIRANE, G YOSHIZAWA, H ONUKI, Y TI INCOMMENSURATE MAGNETIC PHASES IN NDIN3 NEAR TN SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Letter AB Neutron diffraction studies reveal the presence of two incommensurate magnetic phases (IC1 and IC2) between the paramagnetic and antiferromagnetic (AF) phases of the rare-earth compound NdIn3, in a narrow temperature range just below T(N) = 6 K, where the collinear magnetic moments parallel to the tetragonal c axis are rectangularly modulated along the c axis. With decreasing temperature, the modulation wave number changes discontinuously from approximately 0.04c* in the IC1 phase through approximately 0.016c* in the IC2 phase to 0c* in the AF phase. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. UNIV TOKYO,INST SOLID STATE PHYS,TOKYO 106,JAPAN. UNIV TSUKUBA,INST MAT SCI,TSUKUBA,IBARAKI 305,JAPAN. RP MITSUDA, S (reprint author), SCI UNIV TOKYO,DEPT PHYS SCI,TOKYO 162,JAPAN. OI Gehring, Peter/0000-0002-9236-2046 NR 4 TC 8 Z9 8 U1 0 U2 0 PU PHYSICAL SOCIETY JAPAN PI TOKYO PA KIKAI-SHINKO BUILDING, 3-5-8 SHIBA-KOEN, MINATO-KU, TOKYO 105, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD MAY PY 1992 VL 61 IS 5 BP 1469 EP 1472 DI 10.1143/JPSJ.61.1469 PG 4 WC Physics, Multidisciplinary SC Physics GA HX569 UT WOS:A1992HX56900011 ER PT J AU MAIENSCHEIN, JL HUDSON, RS TSUGAWA, RT FEARON, EM SOUERS, PC COLLINS, GW AF MAIENSCHEIN, JL HUDSON, RS TSUGAWA, RT FEARON, EM SOUERS, PC COLLINS, GW TI SEPARATION OF HYDROGEN ISOTOPES BY SELECTIVE ADSORPTION WITH PRODUCTION OF HIGH-PURITY D-T AND T(2) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID ZEOLITES; TRITIUM AB Selective adsorption on a solid at 20 K provides the means to separate hydrogen isotopes, and particularly to purify small quantities of molecular D-T or produce pure J = 1 T2 for nuclear spin polarization. We develop adsorption isotherms and separation factors for several solids from literature data. Our computational model of adsorption column operation, developed to determine column sensitivity to key parameters, is described. Model results show that column diameter and length, particle diameter, choice of solid, and the fractional void space of the packed solid are all key parameters in determination of total purification capacity of a column. Zeolite 13X is shown to be the optimal adsorbent. Column design and operation is discussed in context of the calculational results. We present experimental data that demonstrate successful operation of an adsorption column in purification of D-T gas by removal of T2, and discuss advantages of this technique over conventional separation means. RP MAIENSCHEIN, JL (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 79 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1992 VL 10 IS 3 BP 556 EP 569 DI 10.1116/1.578188 PG 14 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HU242 UT WOS:A1992HU24200023 ER PT J AU MORAN, JM NIGG, DW WHEELER, FJ BAUER, WF AF MORAN, JM NIGG, DW WHEELER, FJ BAUER, WF TI MACROSCOPIC GEOMETRIC HETEROGENEITY EFFECTS IN RADIATION-DOSE DISTRIBUTION ANALYSIS FOR BORON NEUTRON-CAPTURE THERAPY SO MEDICAL PHYSICS LA English DT Article ID BRAIN; WATER; DOGS AB Calculations of radiation flux and dose distributions for boron neutron capture therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This paper describes such a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for the tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for this model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous-tissue model. Comparison of the results showed that peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10%-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models. RP MORAN, JM (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. RI Bauer, William/B-8357-2016 OI Bauer, William/0000-0002-7190-9700 NR 19 TC 16 Z9 16 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0094-2405 J9 MED PHYS JI Med. Phys. PD MAY-JUN PY 1992 VL 19 IS 3 BP 723 EP 732 DI 10.1118/1.596816 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA HZ958 UT WOS:A1992HZ95800029 PM 1508112 ER PT J AU BROCKMAN, FJ KIEFT, TL FREDRICKSON, JK BJORNSTAD, BN LI, SMW SPANGENBURG, W LONG, PE AF BROCKMAN, FJ KIEFT, TL FREDRICKSON, JK BJORNSTAD, BN LI, SMW SPANGENBURG, W LONG, PE TI MICROBIOLOGY OF VADOSE ZONE PALEOSOLS IN SOUTH-CENTRAL WASHINGTON-STATE SO MICROBIAL ECOLOGY LA English DT Article ID DEEP SUBSURFACE SEDIMENTS; BACTERIA; SOIL; ENVIRONMENTS; RESPIRATION; METABOLISM; DIVERSITY; CAROLINA; NUMBERS; WATER AB Three unsaturated subsurface paleosols influenced by moisture recharge, including a highly developed calcic paleosol, were studied to investigate the microbiology of paleosols. Two near-surface paleosols, one impacted by moisture recharge and the other beyond the influence of recharge, were also sampled to directly assess the effect of moisture recharge on the activity and composition of the microbial community associated with paleosols. The highly developed paleosol had a higher population of culturable heterotrophs, a greater glucose mineralization potential, a higher microbial diversity based on colony morphology, and a more than 20-fold higher concentration of ATP than the two weakly developed paleosols. The recharged near-surface paleosol, as compared to the near-surface paleosol unaffected by recharge, had a lower population of culturable heterotrophs, smaller mineralization rate constant, and lower richness based on colony morphology. The recharged paleosols contained predominantly gram-negative isolates, whereas the paleosol unaffected by recharge contained predominantly gram-positive isolates. Storage at 4-degrees-C of subsurface and near-surface paleosol samples containing high water potential increased the population of culturable aerobic heterotrophs, decreased diversity in colony morphology, and increased first-order rate constants and decreased lag times for glucose mineralization. These results indicate that aerobic heterotrophs are present in deep vadose zone paleosols and that there is potential for stimulation of their in situ growth and activity. C1 NEW MEXICO INST MIN & TECHNOL, SOCORRO, NM 87801 USA. SPOKANE FALLS COMMUNITY COLL, SPOKANE, WA USA. RP BROCKMAN, FJ (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. RI Long, Philip/F-5728-2013 OI Long, Philip/0000-0003-4152-5682 NR 57 TC 88 Z9 89 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD MAY-JUN PY 1992 VL 23 IS 3 BP 279 EP 301 DI 10.1007/BF00164101 PG 23 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA JA623 UT WOS:A1992JA62300006 PM 24192936 ER PT J AU PHAM, H AF PHAM, H TI OPTIMAL SYSTEM-PROFIT DESIGN OF K-TO-1-OUT-OF-N SYSTEMS SO MICROELECTRONICS AND RELIABILITY LA English DT Article AB A k-to-l-out-of-n system is a noncoherent system in which no fewer than k and no more than l out of n units are to function for the successful operation of the system. Examples of noncoherent systems are found in communication, multiprocessor and transportation systems. A noncoherent system is very general and includes the parallel, series and N-Modular Redundancy (NMR) systems as special cases. In this paper, for fixed k and l we determine the optimal system size which maximizes the average system profit. A numerical example is provided to illustrate the results. RP PHAM, H (reprint author), EG&G IDAHO INC,NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD MAY PY 1992 VL 32 IS 5 BP 711 EP 718 DI 10.1016/0026-2714(92)90629-Y PG 8 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA HN347 UT WOS:A1992HN34700018 ER PT J AU CUDDEFORD, P AMENDT, P AF CUDDEFORD, P AMENDT, P TI THE RADIUS DEPENDENCE OF VELOCITY DISPERSION IN SPIRAL GALAXIES SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID SURFACE MASS DENSITY; GALACTIC DISK; 3-DIMENSIONAL DISTRIBUTION; SPHERICAL GALAXIES; STELLAR KINEMATICS; ROTATION CURVES; MODAL APPROACH; DARK MATTER; SUN; MODEL AB The analytical model discussed in two previous papers is used to solve for the radial profile of the radial velocity dispersion on the plane of symmetry of an old galactic disc population. For a realistic total mass distribution consistent with an almost flat rotation curve and an exponential density profile, it is found that for relatively small radii a constant-anisotropy model provides a reasonable approximation to the solution (as found observationally by Lewis & Freeman), while for large R the solution is consistent with an approximately constant Toomre-Q profile, as suggested theoretically by Toomre and numerically by Sellwood & Carlberg. Possible applications of this result are discussed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. SISSA,I-34014 TRIESTE,ITALY. OSSERV ASTRON TRIESTE,I-34131 TRIESTE,ITALY. NR 56 TC 14 Z9 14 U1 1 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 1992 VL 256 IS 1 BP 166 EP 176 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HR604 UT WOS:A1992HR60400015 ER PT J AU BADER, DC MCKEE, TB AF BADER, DC MCKEE, TB TI MESOSCALE BOUNDARY-LAYER EVOLUTION OVER COMPLEX TERRAIN .2. FACTORS CONTROLLING NOCTURNAL BOUNDARY-LAYER STRUCTURE SO MONTHLY WEATHER REVIEW LA English DT Article ID NUMERICAL-SIMULATION; FLUXES; MODEL; FLOWS AB The development of the nocturnal boundary layer (NBL) over a sloping plateau upwind of a high mountain barrier is studied with a numerical model and field observations. Six numerical simulations and one observed case are used to describe the effects of wind speed, wind direction, and sunset mixed-layer depth on the NBL structure 6 h after sunset. When there is a component of wind into barrier, a two-layer structure develops. A 75-175-m-deep inversion layer that is topped by a 200-300-m-deep, less stable transition layer extends over the length of the plateau. Shear between the 3-4 m s-1 drainage winds in the inversion layer and the large-scale wind mix cold air vertically to build the transition layer. The inversion layer appears to be relatively insensitive to changes in the external parameters, but transition-layer depth is proportional to wind speed. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. RI Bader, David/H-6189-2011 OI Bader, David/0000-0003-3210-339X NR 10 TC 2 Z9 2 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1992 VL 120 IS 5 BP 802 EP 816 DI 10.1175/1520-0493(1992)120<0802:MBLEOC>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HR104 UT WOS:A1992HR10400009 ER PT J AU DORAN, JC SKYLLINGSTAD, ED AF DORAN, JC SKYLLINGSTAD, ED TI MULTIPLE-SCALE TERRAIN FORCING OF LOCAL WIND FIELDS SO MONTHLY WEATHER REVIEW LA English DT Article ID TURBULENCE CLOSURE-MODEL; NUMERICAL-SIMULATION; SLOPE; FLOWS AB Observations and numerical simulations with a hydrostatic model are used to examine effects of regional and local terrain, synoptic forcing, and stability on the wind fields of an intermountain basin. The study area is centered on the Hanford site in southeast Washington. Two wintertime case studies are presented, each characterized by a surface inversion but with different synoptic forcing. In both cases. the local topography produces a region of blocked flow and significant horizontal wind shear, but slight differences in the direction of the synoptic winds lead to marked differences in the subsequent development of the wind fields over the site. Numerical experiments show that these differences are related to flow through gaps in the Cascade Mountains over 100 km to the west. Additional experiments show that a modest increase in vertical wind shear can cause significant alterations in the local flow patterns, the elimination of the blocked-flow region, and less sensitivity to regional or local terrain effects. Increased solar insolation also weakens the blocking effect of local terrain, but the effects of the Cascade Mountains can still be discerned. RP DORAN, JC (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 11 TC 4 Z9 4 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1992 VL 120 IS 5 BP 817 EP 825 DI 10.1175/1520-0493(1992)120<0817:MSTFOL>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HR104 UT WOS:A1992HR10400010 ER PT J AU FOSTER, I GROPP, W STEVENS, R AF FOSTER, I GROPP, W STEVENS, R TI THE PARALLEL SCALABILITY OF THE SPECTRAL TRANSFORM METHOD SO MONTHLY WEATHER REVIEW LA English DT Article AB This paper investigates the suitability of the spectral transform method for parallel implementation. The spectral transform method is a natural candidate for general circulation models (GCMs) designed to run on large-scale parallel computers due to the large number of existing serial and moderately parallel implementations. Analytic and empirical studies are presented that allow the parallel performance, and hence the scalability, of the spectral transform method to be quantified on different parallel computer architectures. Both the shallow-water equations and complete GCMs are considered. Results indicate that for the shallow-water equations, parallel efficiency is generally poor because of high communication requirements. It is predicted that for complete global climate models, the parallel efficiency will be significantly better; nevertheless. projected teraflop computers will have difficulty achieving acceptable throughput necessary for long-term regional climate studies. RP FOSTER, I (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. OI Gropp, William/0000-0003-2905-3029 NR 20 TC 22 Z9 22 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1992 VL 120 IS 5 BP 835 EP 850 DI 10.1175/1520-0493(1992)120<0835:TPSOTS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HR104 UT WOS:A1992HR10400012 ER PT J AU CASEY, WH EGGLESTON, C JOHNSSON, PA WESTRICH, HR HOCHELLA, MF AF CASEY, WH EGGLESTON, C JOHNSSON, PA WESTRICH, HR HOCHELLA, MF TI AQUEOUS SURFACE-CHEMISTRY AND CORROSION OF MINERALS SO MRS BULLETIN LA English DT Article ID ATOMIC-FORCE MICROSCOPE; DISSOLUTION C1 STANFORD UNIV, DEPT APPL EARTH SCI, STANFORD, CA 94305 USA. SANDIA NATL LABS, DIV GEOCHIM, ALBUQUERQUE, NM 87185 USA. STANFORD UNIV, DEPT GEOL, STANFORD, CA 94305 USA. RP CASEY, WH (reprint author), UNIV CALIF DAVIS, DEPT LAND AIR & WATER RESOURCES, DAVIS, CA 95616 USA. NR 30 TC 5 Z9 5 U1 1 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0883-7694 EI 1938-1425 J9 MRS BULL JI MRS Bull. PD MAY PY 1992 VL 17 IS 5 BP 23 EP 29 PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA HU968 UT WOS:A1992HU96800002 ER PT J AU SCHWARTZ, JL MOAN, E MUSTAFI, R FINK, L YASUI, LS AF SCHWARTZ, JL MOAN, E MUSTAFI, R FINK, L YASUI, LS TI FASTER RATES OF DNA UNWINDING UNDER ALKALINE CONDITIONS IN XRS-5 CELLS MAY REFLECT CHROMATIN STRUCTURE ALTERATIONS SO MUTATION RESEARCH LA English DT Article DE CHROMOSOME STRUCTURE; NUCLEAR MATRIX; ALKALINE UNWINDING; DNA STRAND BREAKS; RADIATION SENSITIVITY ID DOUBLE-STRAND BREAKS; NEUTRAL FILTER ELUTION; RAY-SENSITIVE MUTANTS; HAMSTER OVARY CELLS; MAMMALIAN-CELLS; REPAIR; RADIATION; DAMAGE; LINE AB The Chinese hamster ovary (CHO) cell line xrs-5 is a radiation-sensitive mutant isolated from CHO-K1 cells. The radiation sensitivity is associated with a defect in DNA double-strand break rejoining. The DNA alkaline unwinding technique was used to measure the DNA single-strand breakage caused by gamma-rays in xrs-5 and CHO-K1 cells. Greater rates of DNA unwinding were found in xrs-5 cells as compared to CHO-K1. Independent measurement of DNA strand breakage by DNA filter elution or pulsed-field gel electrophoresis failed to show any difference between the two cell lines. The greater rate of unwinding in xrs-5 cells may reflect an alteration in chromosome structure. C1 UNIV CHICAGO,MED CTR,DEPT RADIAT & CELLULAR ONCOL,CHICAGO,IL 60637. NO ILLINOIS UNIV,DEPT BIOL SCI,DE KALB,IL 60115. RP SCHWARTZ, JL (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,9700 S CASS AVE,BIM 202,ARGONNE,IL 60439, USA. FU NCI NIH HHS [CA45011] NR 17 TC 7 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD MAY PY 1992 VL 282 IS 1 BP 13 EP 17 DI 10.1016/0165-7992(92)90067-R PG 5 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA HR096 UT WOS:A1992HR09600003 PM 1374151 ER PT J AU WILKIE, TM GILBERT, DJ OLSEN, AS CHEN, XN AMATRUDA, TT KORENBERG, JR TRASK, BJ DEJONG, P REED, RR SIMON, MI JENKINS, NA COPELAND, NG AF WILKIE, TM GILBERT, DJ OLSEN, AS CHEN, XN AMATRUDA, TT KORENBERG, JR TRASK, BJ DEJONG, P REED, RR SIMON, MI JENKINS, NA COPELAND, NG TI EVOLUTION OF THE MAMMALIAN G-PROTEIN ALPHA-SUBUNIT MULTIGENE FAMILY SO NATURE GENETICS LA English DT Article ID GTP-BINDING PROTEIN; GENETIC-LINKAGE MAP; SIGNAL-TRANSDUCTION; MOLECULAR CHARACTERIZATION; HEREDITARY OSTEODYSTROPHY; INTERSPECIFIC BACKCROSS; INSITU HYBRIDIZATION; ADENYLATE-CYCLASE; PERTUSSIS TOXIN; HIGH-RESOLUTION AB Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. The multigene family of G protein alpha-subunits, which interact with receptors and effectors, exhibit a high level of sequence diversity. In mammals, 15 G-alpha subunit genes can be grouped by sequence and functional similarities into four classes. We have determined the murine chromosomal locations of all 15 G-alpha subunit genes using an interspecific backcross derived from crosses of C57BL/6J and Mus spretus mice. These data, in combination with mapping studies in humans, have provided insight into the events responsible for generating the genetic diversity found in the mammalian alpha-subunit genes and a framework for elucidating the role of the G-alpha subunits in disease. C1 NCI,FREDERICK CANC RES & DEV CTR,ABL BASIC RES PROGRAM,MAMMALIAN GENET LAB,FREDERICK,MD 21702. CALTECH,DIV BIOL 14775,PASADENA,CA 91125. JOHNS HOPKINS UNIV,SCH MED,HOWARD HUGHES MED INST,DEPT MOLEC BIOL & GENET,BALTIMORE,MD 21205. LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI L452,LIVERMORE,CA 94550. CEDARS SINAI MED CTR,DEPT PEDIAT,CTR BIRTH DEFECTS,LOS ANGELES,CA 90048. NR 76 TC 212 Z9 214 U1 1 U2 9 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1061-4036 J9 NAT GENET JI Nature Genet. PD MAY PY 1992 VL 1 IS 2 BP 85 EP 91 DI 10.1038/ng0592-85 PG 7 WC Genetics & Heredity SC Genetics & Heredity GA JC980 UT WOS:A1992JC98000005 PM 1302014 ER PT J AU WATERSTON, R MARTIN, C CRAXTON, M HUYNH, C COULSON, A HILLIER, L DURBIN, R GREEN, P SHOWNKEEN, R HALLORAN, N METZSTEIN, M HAWKINS, T WILSON, R BERKS, M DU, Z THOMAS, K THIERRYMIEG, J SULSTON, J AF WATERSTON, R MARTIN, C CRAXTON, M HUYNH, C COULSON, A HILLIER, L DURBIN, R GREEN, P SHOWNKEEN, R HALLORAN, N METZSTEIN, M HAWKINS, T WILSON, R BERKS, M DU, Z THOMAS, K THIERRYMIEG, J SULSTON, J TI A SURVEY OF EXPRESSED GENES IN CAENORHABDITIS-ELEGANS SO NATURE GENETICS LA English DT Article ID CHROMOSOME; DNA; MUTATIONS; SEQUENCE; GENOME AB As an adjunct to the genomic sequencing of Caenorhabditis elegans, we have investigated a representative cDNA library of 1,517 clones. A single sequence read has been obtained from the 5' end of each clone, allowing its characterization with respect to the public databases, and the clones are being localized on the genome map. The result is the identification of about 1,200 of the estimated 15,000 genes of C. elegans. More than 30% of the inferred protein sequences have significant similarity to existing sequences in the databases, providing a route towards in vivo analysis of known genes in the nematode. These clones also provide material for assessing the accuracy of predicted exons and splicing patterns and will lead to a more accurate estimate of the total number of genes in the organism than has hitherto been available. C1 LAWRENCE LIVERMORE NATL LAB, CTR HUMAN GENOME, LIVERMORE, CA 94550 USA. MRC, MOLEC BIOL LAB, CAMBRIDGE CB2 2QH, ENGLAND. CTR RECH BIOL MOLEC & PHYS MATH, CNRS, F-34044 MONTPELLIER, FRANCE. RP WASHINGTON UNIV, SCH MED, DEPT GENET, BOX 8232, 4566 SCOTT AVE, ST LOUIS, MO 63110 USA. RI THIERRY-MIEG, Jean/F-1975-2017 OI THIERRY-MIEG, Jean/0000-0002-0396-6789 NR 32 TC 345 Z9 345 U1 0 U2 1 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 1061-4036 EI 1546-1718 J9 NAT GENET JI Nature Genet. PD MAY PY 1992 VL 1 IS 2 BP 114 EP 123 DI 10.1038/ng0592-114 PG 10 WC Genetics & Heredity SC Genetics & Heredity GA JC980 UT WOS:A1992JC98000010 PM 1302004 ER PT J AU BARKIGIA, KM THOMPSON, MA FAJER, J PANDEY, RK SMITH, KM VICENTE, MGH AF BARKIGIA, KM THOMPSON, MA FAJER, J PANDEY, RK SMITH, KM VICENTE, MGH TI CONFORMATIONAL FLEXIBILITY OF CHLORIN MACROCYCLES - STRUCTURAL DETERMINATIONS AND THEORETICAL CALCULATIONS OF A BENZOCHLORIN, A MESO-DIMETHYL CHLORIN AND A NICKEL CHLORIN SO NEW JOURNAL OF CHEMISTRY LA English DT Article ID DIFFERENTIAL-OVERLAP TECHNIQUE; PHOTOSYNTHETIC REACTION CENTER; BACTERIOCHLOROPHYLL-B DIMER; RANDOM PHASE APPROXIMATION; INTERMEDIATE NEGLECT; MOLECULAR-STRUCTURE; PROSTHETIC GROUP; HEME-D; RHODOPSEUDOMONAS-VIRIDIS; ELECTRONIC-STRUCTURE AB X-ray Structures of three chlorins with different peripheral substituents are reported. The conformations of the molecules range from nearly planar to severely puckered and illustrate the multi-conformational surfaces that chlorins can adopt. These results further demonstrate the skeletal flexibility of porphyrin derivatives and reinforce the premise that conformational variations can modulate the physical and chemical properties of porphinoids in vitro and in vivo (Barkigia et al., J. Am. Chem. Soc., 1988, 110, 7566). Interest in the roles of chlorins in solar energy conversion, electron transfer, and photodynamic therapy raises the question whether theoretical computations can offer a rationale for the properties of existing compounds or provide guidelines for the syntheses of new molecules. The crystallographic data reported here were thus used to calculate the optical properties of the chlorins with the semi-empirical spectroscopic INDO/S method, both in its standard form that includes single-only excitations in the configuration interactions from the ground state, and with the random phase approximation that includes some double excitations. The calculations yield reasonable agreement with experiment including the Soret bands, and further suggest that one of the ruffled structures observed in the crystals may be more relaxed in solution. The results thus illustrate the usefulness (and limitations) of the theory. Crystallographic data: Benzochlorin 1. N4C39H48: triclinic space group P1BAR, a = 13.441(8) angstrom, b = 13.941(4) angstrom, c = 9.1 38(2) angstrom, alpha = 100.94(2)-degrees, beta = 95.91(4)-degrees, gamma = 79.05(4)-degrees, Z = 2; R(F) = 0.071 and R(wF) = 0.072, based on 2444 reflections with F0 > 2-sigma-F0, T= 200K. Dimethyl chlorin 2, N4C38H52: monoclinic space group C2/c, a = 22.249(9) angstrom, b = 11.704(3) angstrom, c = 27.646(6) angstrom, beta = 105.56(3)-degrees, Z = 8; R(F) = 0.079 and R(wF) = 0.077 based on 3075 reflections with F0 > 3-sigma-F0, T= 298K. Ni chlorin 3, NiN4C36O4H40.CH3OH: monoclinic space group C2/c, a = 23.634(6) angstrom, b = 14.522(1) angstrom, c = 21.801(5) angstrom, beta = 114.27(2)-degrees, Z = 8; R(F) = 0.055 and R(wF) = 0.056 based on 2044 reflections with F0 > 2-sigma-F0, T = 298K. C1 UNIV CALIF DAVIS,DEPT CHEM,DAVIS,CA 95616. RP BARKIGIA, KM (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. RI Smith, Kevin/G-1453-2011 OI Smith, Kevin/0000-0002-6736-4779 NR 63 TC 31 Z9 31 U1 0 U2 1 PU GAUTHIER-VILLARS PI PARIS PA S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE SN 1144-0546 J9 NEW J CHEM JI New J. Chem. PD MAY PY 1992 VL 16 IS 5 BP 599 EP 607 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA JK625 UT WOS:A1992JK62500013 ER PT J AU HU, SG LI, J AF HU, SG LI, J TI ON EVENTUAL BOUNDEDNESS OF LOTKA-VOLTERRA ECOLOGICAL-SYSTEMS SO NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS LA English DT Article DE LOTKA-VOLTERRA SYSTEMS; PREDATOR PREY SYSTEMS; GRAPH THEORY; EVENTUAL BOUNDEDNESS C1 UNIV ALABAMA,DEPT MATH SCI,HUNTSVILLE,AL 35899. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP HU, SG (reprint author), HUAZHONG UNIV SCI & TECHNOL,DEPT MATH,WUHAN,PEOPLES R CHINA. NR 17 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0362-546X J9 NONLINEAR ANAL-THEOR JI Nonlinear Anal.-Theory Methods Appl. PD MAY PY 1992 VL 18 IS 10 BP 917 EP 928 DI 10.1016/0362-546X(92)90129-3 PG 12 WC Mathematics, Applied; Mathematics SC Mathematics GA HZ670 UT WOS:A1992HZ67000002 ER PT J AU KWONG, MK AF KWONG, MK TI ON THE UNBOUNDEDNESS OF THE NUMBER OF SOLUTIONS OF A DIRICHLET PROBLEM SO NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS LA English DT Article DE NONLINEAR BOUNDARY VALUE PROBLEM; VARIATION INDEX; SHOOTING METHOD; MULTIPLICITY OF SOLUTIONS ID UNIQUENESS RP KWONG, MK (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439, USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0362-546X J9 NONLINEAR ANAL-THEOR JI Nonlinear Anal.-Theory Methods Appl. PD MAY PY 1992 VL 18 IS 10 BP 993 EP 1001 DI 10.1016/0362-546X(92)90134-Z PG 9 WC Mathematics, Applied; Mathematics SC Mathematics GA HZ670 UT WOS:A1992HZ67000007 ER PT J AU CAMASSA, R FOREST, MG KNAPP, R AF CAMASSA, R FOREST, MG KNAPP, R TI ENHANCEMENT OF OPTICAL BISTABILITY BY PERIODIC LAYERING SO NONLINEARITY LA English DT Article ID MEDIA AB We study analytically and numerically the effect of a periodic perturbation in the index of refraction of a nonlinear optical medium. Using a one-dimensional model for monochromatic waves incident on the medium, we find that near resonance between the perturbation and the modulation of the electric field there can be a significant enhancement of optical bistability in the low intensity regime. In particular, we discuss in detail the case of the primary resonance, which is responsible for the most significant effects, and show how one can optimize the bistability curve for the implementation of an optical switch, based on the information provided by the resonance structure. C1 OHIO STATE UNIV,DEPT MATH,COLUMBUS,OH 43210. LOS ALAMOS NATL LAB,DIV COMP & COMMUNICAT,LOS ALAMOS,NM 87545. RP CAMASSA, R (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0951-7715 J9 NONLINEARITY JI Nonlinearity PD MAY PY 1992 VL 5 IS 3 BP 721 EP 742 DI 10.1088/0951-7715/5/3/006 PG 22 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA HY500 UT WOS:A1992HY50000006 ER PT J AU BILLONE, MC MONTGOMERY, RO RASHID, YR HEAD, JL AF BILLONE, MC MONTGOMERY, RO RASHID, YR HEAD, JL TI ADVANCEMENTS IN THE BEHAVIORAL MODELING OF FUEL-ELEMENTS AND RELATED STRUCTURES SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article AB An important aspect of the design and analysis of nuclear reactors is the ability to predict the behavior of fuel elements in the adverse environment of a reactor system. By understanding the thermomechanical behavior of the different materials which constitute a nuclear fuel element, analysis and predictions can be made regarding the integrity and reliability of fuel element designs. The SMiRT conference series, through the division on fuel elements and the post-conference seminars on fuel element modeling, provided technical forums for the international participation in the exchange of knowledge concerning the thermomechanical modeling of fuel elements. This paper discusses the technical advances in the behavioral modeling of fuel elements presented at the SMiRT conference series since its inception in 1971. Progress in the areas of material properties and constitutive relationships, modeling methodologies, and integral modeling approaches was reviewed and is summarized in light of their impact on the thermomechanical modeling of nuclear fuel elements. C1 ANATECH RES CORP,SAN DIEGO,CA. ROYAL NAVAL COLL,LONDON,ENGLAND. RP BILLONE, MC (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 33 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 1 BP 23 EP 36 DI 10.1016/0029-5493(92)90005-G PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HW788 UT WOS:A1992HW78800004 ER PT J AU PARKS, MB CLAUSS, DB AF PARKS, MB CLAUSS, DB TI PERFORMANCE OF CONTAINMENT PENETRATIONS UNDER SEVERE ACCIDENT LOADINGS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB The paper provides a summary of efforts to date to better understand the leakage behavior of containment penetrations when subjected to severe accident conditions. The research activities discussed herein are a part of the Containment Integrity Programs, which are managed by Sandia National Laboratories for the U.S. Nuclear Regulatory Commission. Past containment penetration research topics, which are briefly described, include testing of typical compression seals and gaskets, electrical penetration assemblies, and a personnel airlock, as well as an investigation of leakage due to ovalization of penetration sleeves. The primary focus of the paper is on recent or ongoing research programs on the behavior of inflatable seals, bellows, and of pressure unseating equipment hatches. RP PARKS, MB (reprint author), SANDIA NATL LABS,DIV CONTAINMENT TECHNOL,6523,ALBUQUERQUE,NM 87185, USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 177 EP 197 DI 10.1016/0029-5493(92)90138-L PG 21 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100004 ER PT J AU SHAH, VN LOWENSTEIN, DB TURNER, APL WARD, SR GORMAN, JA MACDONALD, PE WEIDENHAMER, GH AF SHAH, VN LOWENSTEIN, DB TURNER, APL WARD, SR GORMAN, JA MACDONALD, PE WEIDENHAMER, GH TI ASSESSMENT OF PRIMARY WATER-STRESS CORROSION CRACKING OF PWR STEAM-GENERATOR TUBES SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB This paper presents a model for assessing primary water stress corrosion cracking (PWSCC) damage to pressurized water reactor (PWR) steam generator tubes. PWSCC damage has been detected at three locations in the recirculating steam generator: expansion transition regions, U-bends, and tube dents. The model accounts for residual stresses, microstructure, and primary coolant temperatures. High residual tensile stresses and low mill-annealing temperatures contribute significantly to PWSCC. PWSCC is a thermally activated process; small increases in operating temperature accelerate damage. The model employs a Weibull distribution to represent tube degradation results obtained from inservice inspections and from destructive examinations. The model can be used to estimate the times to steam generator tube failures caused by PWSCC. This paper also evaluates remedial measures for PWSCC damage and presents a procedure for life assessment of steam generator tubes. C1 NUCL REGULATORY COMMISS,WASHINGTON,DC 20555. RP SHAH, VN (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 33 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 199 EP 215 DI 10.1016/0029-5493(92)90139-M PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100005 ER PT J AU CORWIN, WR NANSTAD, RK ISKANDER, SK HAGGAG, FM AF CORWIN, WR NANSTAD, RK ISKANDER, SK HAGGAG, FM TI HEAVY-SECTION STEEL IRRADIATION PROGRAM SUMMARY SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB In light-water-cooled nuclear power plants, a steel reactor pressure vessel (RPV) forms the primary containment boundary for the nuclear fuel assembly. Since a failure of the RPV carries the potential of major contamination release and severe accident, it is imperative to safe reactor operation to understand and be able to accurately predict realistic failure models of the vessel material. A major known risk arises from irradiation-induced degradation of the RPV fracture resistance which occurs as a result of normally occurring neutron flux during the service life of the reactor. Better understanding of the irradiation degradation of the vessel material will provide better input to improve the engineering models vital for prediction of RPV integrity and safe service life. For this reason, the Heavy-Section Steel Irradiation (HSSI) Program has been established with its primary goal to provide a thorough, quantitative assessment of the effects of neutron irradiation on the material behavior, and in particular the fracture toughness properties, of typical pressure vessel steels as they relate to light-water RPVs. The program includes the direct continuation of irradiation studies previously conducted within the Heavy-Section Steel Technology Program augmented by enhanced "aminations of the accompanying microstructural changes. Effects of specimen size, material chemistry, product form and microstructure, irradiation fluence, flux, temperature and spectrum, and postirradiation annealing are being examined on a wide range of fracture properties including fracture toughness (K(Ic) and J(Ic)), crack-arrest toughness (K(Ia)), ductile tearing resistance (dJ/da), Charpy V-notch impact energy, dropweight nil-ductility temperature (NDT), and tensile properties. Models based on observations of radiation-induced microstructural changes using field ion and high-resolution transmission electron microscopy provide a firmer basis for extrapolating the measured changes in fracture properties to wider ranges of irradiation conditions. The principal materials examined within the HSSI Program are highcopper welds since their postirradiation properties are most frequently limiting in the continued safe operation of commercial RPVs. In addition, a limited effort Will focus on stainless steel weld overlay cladding, typical of that used on the inner surface of RPVs, since its postirradiation fracture properties have the potential for strongly affecting the "tension of small surface flaws during overcooling transients. Results from the HSSI studies will be integrated to aid in resolving major regulatory issues facing the U.S. Nuclear Regulatory Commission which involve. RPV irradiation embrittlement such as pressurized-thermal shock, operating pressure-temperature limits, low-temperature overpressurization, and the specialized problems associated with low upper-shelf welds. Taken together the results of these studies also provide guidance and bases for evaluating both the aging behavior and the potential for plant life extension of light-water RPVs. RP CORWIN, WR (reprint author), OAK RIDGE NATL LAB,HEAVY SECT STEEL IRRADIAT PROGRAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 15 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 227 EP 243 DI 10.1016/0029-5493(92)90141-H PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100007 ER PT J AU CHRISTENSEN, JA AF CHRISTENSEN, JA TI MANAGING AGING IN NUCLEAR-POWER-PLANTS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB Aging degradation in nuclear power plants must be controlled to prevent safety margins from declining below limits provided in plant design bases. The NPAR Program and other aging-related programs conducted under the auspices of the NRC Office of Research are developing needed technical guidance for control of aging. Results from these programs, together with relevant information developed by industry and elsewhere, are implemented through various ongoing NRC and industry programs and initiatives as well as by means of conventional regulatory instruments. The aging control process central to these efforts consists of three key elements: (1) selection of components, systems, and structures (CSS) in which aging must be controlled, (2) understanding of the mechanisms and rates of degradation in these CSS, and (3) managing degradation through effective surveillance and maintenance. These elements are addressed in Recommended Practices Guidance that integrates information developed under NPAR and other studies of aging into a systems-oriented format that tracks directly with the Safety Analysis Reports and with the NRC Standard Review Plan (NUREG-0800). RP CHRISTENSEN, JA (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 13 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 245 EP 256 DI 10.1016/0029-5493(92)90142-I PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100008 ER PT J AU SCOTT, WB ENDERLIN, WI CHOCKIE, AD BJORKELO, KA AF SCOTT, WB ENDERLIN, WI CHOCKIE, AD BJORKELO, KA TI GOOD PRACTICES FOR EFFECTIVE MAINTENANCE TO MANAGE AGING OF NUCLEAR-POWER-PLANTS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB Maintenance is the primary means of detecting and correcting the effects of aging degradation at nuclear power plants. The effectiveness of the maintenance program has a direct impact on the operational safety of nuclear power plants. As part of the Nuclear Regulatory Commission NPAR program, the effectiveness of maintenance programs to manage aging were examined for four different governmental and industrial organizations. These were: the U.S. commercial aviation industry, the U.S. Navy ballistic submarine program, the U.S. Air Force B-52 bomber program, and the Japanese nuclear power industry. The purpose was to identify effective maintenance practices that could be adapted by commercial nuclear power plants to assist in managing equipment aging. The key maintenance areas discussed in this paper include the development of systematic maintenance programs, the application of appropriate and effective preventive maintenance tasks and inspections, the collection and evaluation of performance and operating records to assess the effectiveness of the maintenance programs, and the use of feedback and corrective actions to improve the maintenance programs. Also examined is the issue of diminishing manufacturing sources. C1 BATTELLE MEM INST, HUMAN AFFAIRS RES CTR, SEATTLE, WA 98105 USA. RP SCOTT, WB (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 8 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 257 EP 265 DI 10.1016/0029-5493(92)90143-J PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100009 ER PT J AU JACOBUS, MJ AF JACOBUS, MJ TI LOSS-OF-COOLANT ACCIDENT (LOCA) TESTING OF AGED CABLES WITH APPLICATION TO NUCLEAR-PLANT LIFE EXTENSION SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB Sandia National Laboratories is conducting long-term aging research on representative samples of U.S. nuclear power plant Class 1E cables. The objectives of this program are to determine the suitability of these cables for extended life (beyond 40-year design basis) and to assess various cable condition monitoring (CM) techniques for predicting remaining cable life. Twelve different cable products have been artifically aged at relatively mild exposure conditions in three test chambers to nominal equivalent lifetimes of 20, 40, and 60 years based on Arrhenius acceleration theory. After aging, the cables in each chamber were exposed to a sequential accident profile consisting of 1100 kGy of high dose rate gamma irradiation followed by a simulated design basis loss-of-coolant accident (LOCA) steam exposure. This paper presents selected results of the LOCA testing. Although some of the cables experienced electrical failures, the results of these tests indicate a good life extension potential for a number of popular U.S. cable products. Results of the CM techniques are still under evaluation and are not reported here. RP JACOBUS, MJ (reprint author), SANDIA NATL LABS,DIV ASSESSMENT 6447,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 267 EP 275 DI 10.1016/0029-5493(92)90144-K PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100010 ER PT J AU HAYNES, HD AF HAYNES, HD TI EVALUATION OF CHECK VALVE MONITORING METHODS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB Check valves are used extensively in nuclear plant safety systems and balance-of-plant (BOP) systems. Their failures have resulted in significant maintenance efforts and, on occasion, have resulted in water hammer, overpressurization of low-pressure systems and damage to flow system components. Consequently, in recent years check valves have received considerable attention by the Nuclear Regulatory Commission (NRC) and the nuclear power industry. Oak Ridge National Laboratory (ORNL) is carrying out a comprehensive two phase aging assessment of check valves in support of the Nuclear Plant Aging Research (NPAR) program. As part of the second phase, ORNL is evaluating several developmental and/or commercially available check valve diagnostic monitoring methods; in particular, those based on measurements of acoustic emission, ultrasonics, and magnetic flux. These three methods were found to provide different (and complementary) diagnostic information. The combination of acoustic emission with either ultrasonic or magnetic flux monitoring yields a monitoring system that succeeds in providing sensitivity to detect all major check valve operating conditions. The three check valve monitoring methods described in this paper are still under development and are presently being tested as part of a program directed by the Nuclear Industry Check Valve Group (NIC) in conjunction with the Electric Power Research Institute (EPRI). Phase 1 of this program (water testing) is being carried out at the Utah Water Research Laboratory located on the Utah State University campus. RP HAYNES, HD (reprint author), OAK RIDGE NATL LAB,DIV ENGN TECHNOL,POB 2009,OAK RIDGE,TN 37831, USA. NR 8 TC 3 Z9 3 U1 1 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 283 EP 294 DI 10.1016/0029-5493(92)90146-M PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100012 ER PT J AU BANDYOPADHYAY, K HOFMAYER, C AF BANDYOPADHYAY, K HOFMAYER, C TI PARAMETRIC STUDY OF RELAY SEISMIC CAPACITY SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB An evaluation of the existing relay test data base at Brookhaven National Laboratory (BNL) has indicated that the seismic capacity of a relay may depend on various parameters related to the design or the input motion. In order to investigate the effect of these parameters on the seismic fragility level, BNL has conducted a relay test program. Establishing the correlation between the single frequency fragility test input and the corresponding multifrequency response spectrum (TRS) is also an objective of this test program. The testing has been performed at Wyle Laboratories. This paper discusses the methodology used for testing and presents a brief summary of important test results. RP BANDYOPADHYAY, K (reprint author), ASSOCIATED UNIV INC,BROOKHAVEN NATL LAB,DEPT NUCL ENERGY,DIV STRUCT ANAL,UPTON,NY 11973, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 311 EP 317 DI 10.1016/0029-5493(92)90148-O PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100014 ER PT J AU CARTER, RJ AF CARTER, RJ TI HUMAN-FACTORS SURVEY OF ADVANCED INSTRUMENTATION AND CONTROLS TECHNOLOGIES IN NUCLEAR-PLANTS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB A survey of advanced instrumentation and controls (I&C) technologies and associated human factors issues in the nuclear industry was conducted. The objective of the survey was to provide background for the development of regulatory policy, criteria, and guides for review of advanced I&C systems as well as human engineering guidelines for evaluating these systems. The survey was administered at five U.S. nuclear utilities, two advanced reactor and three light water reactor (LWR) vendors, and a Canadian utility and vendor. The results appear to indicate that the nuclear industry has addressed a number of the human factors concerns and potential problems discussed during the survey. It has started to seriously consider the human factors implications of the introduction of advanced I&C into the control room. There are, however, a number of safety-related human factors issues that still need to be investigated. They include: Is an advanced I&C guideline for the interface of the human with displays and controls needed? What changes will there be in the role of the control room operator? The potential problem of information overload needs to be addressed. How should existing training technology be made applicable for advanced I&C? How will operator acceptance and trust be accomplished? RP CARTER, RJ (reprint author), OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,COGNIT SYST & HUMAN FACTORS GRP,POB 2008,OAK RIDGE,TN 37831, USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 319 EP 330 DI 10.1016/0029-5493(92)90149-P PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100015 ER PT J AU OHARA, J HIGGINS, J LUCKAS, W CROUCH, D AF OHARA, J HIGGINS, J LUCKAS, W CROUCH, D TI THE EFFECTS OF LOCAL-CONTROL STATION DESIGN VARIATION ON HUMAN-PERFORMANCE AND PLANT RISK SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB A human factors analysis was performed to assess how selected design variations to local control stations (LCSs) in nuclear power plants affect both human performance and plant risk. Modifications in the design of individual control panels and changes in their functional centralization were considered. The analysis methodology was accomplished in four stages. First, a list of LCS human engineering design deficiencies was developed using data collected from a variety of sources including visits to nuclear power plants. From these data, a set of potential upgrades were defined to correct the deficiencies. Second, the effects of the upgrades on human error probabilities (HEPs) were determined using a computer-based methodology for soliciting expert judgement. Third, the HEPs were propagated through a plant probabilistic risk assessment, and new core melt frequencies were established. The results indicated that implementation of either type of upgrades would improve human performance and lower risk, although the effect of functional centralization on performance and risk was found to be greater than panel design. RP OHARA, J (reprint author), BROOKHAVEN NATL LAB,DEPT NUCL ENERGY,REACTOR OPERAT ANAL GRP,BLDG 130,UPTON,NY 11973, USA. RI Higgins, James/D-6822-2013 NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 331 EP 340 DI 10.1016/0029-5493(92)90150-T PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100016 ER PT J AU SAMANTA, PK VESELY, WE KIM, IS AF SAMANTA, PK VESELY, WE KIM, IS TI TOWARD RISK-BASED CONTROL OF NUCLEAR-POWER-PLANT CONFIGURATIONS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 17TH MEETING ON WATER REACTOR SAFETY INFORMATION CY OCT 23-25, 1989 CL GAITHERSBURG, MD AB This paper presents an analysis of risks associated with component outage configurations during power operation of a nuclear power plant and discusses approaches and strategies for developing a risk-based configuration control system. A configuration, as used here, is a set of component states. The objective of risk-based configuration control is to detect and control plant configurations using a risk perspective. The configuration contributions to core-melt frequency and core-melt probability are studied for two plants. Some equipment configurations can cause large core melt frequency increases and there are a number of such configurations that are not currently controlled by technical specifications. However, the expected frequency of occurrences of the impacting configurations is small and the actual core-melt probability contributions are also generally small. Effective strategies and criteria for controlling configuration risks are presented. Such control strategies take into consideration the risks associated with configurations, the nature and characteristics of the configuration risks, and also the practical considerations such as adequate repair times and/or options to transfer to low risk configurations. Alternative types of criteria are discussed that are not overly restrictive to result in unnecessary plant shutdown, but rather motivate effective test and maintenance practices that control risk-significant configurations to allow continued operation with an adequate margin to meet challenges to safety. RP SAMANTA, PK (reprint author), BROOKHAVEN NATL LAB,DEPT NUCL ENERGY,DIV ENGN TECHNOL,RISK & RELIABIL ANAL GRP,BLDG 130,UPTON,NY 11973, USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1992 VL 134 IS 2-3 BP 355 EP 370 DI 10.1016/0029-5493(92)90152-L PG 16 WC Nuclear Science & Technology SC Nuclear Science & Technology GA JC311 UT WOS:A1992JC31100018 ER PT J AU SULLIVAN, TJ AF SULLIVAN, TJ TI READY FOR ANYTHING SO NUCLEAR ENGINEERING INTERNATIONAL LA English DT Article RP SULLIVAN, TJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU REED BUSINESS PUBLISHING LTD PI SUTTON PA QUADRANT HOUSE THE QUADRANT, SUTTON, SURREY, ENGLAND SM2 5AS SN 0029-5507 J9 NUCL ENG INT JI Nucl. Eng. Int. PD MAY PY 1992 VL 37 IS 454 BP 14 EP 16 PG 3 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HT518 UT WOS:A1992HT51800004 ER PT J AU DEVOTO, RS BLACKFIELD, DT FENSTERMACHER, ME BONOLI, PT PORKOLAB, M TINIOS, G AF DEVOTO, RS BLACKFIELD, DT FENSTERMACHER, ME BONOLI, PT PORKOLAB, M TINIOS, G TI MODELING OF LOWER HYBRID CURRENT DRIVE IN SELF-CONSISTENT ELONGATED TOKAMAK EQUILIBRIA SO NUCLEAR FUSION LA English DT Article ID ALCATOR-C TOKAMAK; BOOTSTRAP CURRENT; TEARING MODE; PLASMAS; CONFINEMENT; STABILIZATION; TRANSPORT; JT-60; WAVES AB A simulation model for current drive by lower hybrid slow waves has been generalized to accommodate elongated plasma cross-sections. Toroidal ray trajectories are computed from the magnetic field, density and temperature distributions obtained from a numerical, free boundary solution of the Grad-Shafranov equation. A numerical solution of a relativistic Fokker-Planck equation is used to compute the absorbed power and the driven current. This lower hybrid model has been incorporated into the ACCOME code which iterates between solutions of the Grad-Shafranov equation and computation of the driven current until a self-consistent solution is obtained. Current driven by neutral beams, neoclassical effects and an Ohmic electric field in addition to lower hybrid waves is included. The model is applied to the proposed ITER design under steady state, non-inductive operation. C1 MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. RP DEVOTO, RS (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 37 TC 32 Z9 32 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 MAY PY 1992 VL 32 IS 5 BP 773 EP 786 DI 10.1088/0029-5515/32/5/I05 PG 14 WC Physics, Fluids & Plasmas SC Physics GA HZ838 UT WOS:A1992HZ83800005 ER PT J AU TAKAHASHI, H CHANCE, MS KESSEL, CE LEBLANC, B MANICKAM, J OKABAYASHI, M AF TAKAHASHI, H CHANCE, MS KESSEL, CE LEBLANC, B MANICKAM, J OKABAYASHI, M TI USE OF THE S-ALPHA DIAGRAM FOR REPRESENTING TOKAMAK EQUILIBRIA IN PROFILE MODIFICATION RESEARCH SO NUCLEAR FUSION LA English DT Article ID BOOTSTRAP CURRENT; CONFINEMENT; PLASMAS; INJECTION; ASDEX; SHAPE AB In tokamak research involving plasma profile modification, it is proposed to represent a plasma equilibrium state as a trajectory in a diagram of shear and dimensionless pressure gradient commonly known as the S-alpha diagram. The method is a natural way of exhibiting local variations of the shear and pressure gradient and their interrelationship. A distinct equilibrium trajectory pattern may be associated with a set of experimentally observed phenomena, such as the level and kind of MHD activity or confinement, or with theoretically predicted properties such as the stability. When many qualitatively different trajectory patterns are identified with a set of observed or predicted characteristics, the diagram will serve as a tool for cataloguing the presently achievable plasma states as well as desired target states through 'pattern recognition'. Furthermore, types of trajectory changes produced by various profile modification techniques can also be represented in the same diagram. The method will help construct a desired state, starting from a given experimental state using profile modification techniques. It is demonstrated, using PBX-M experiments as examples, that distinct trajectory patterns can be associated with different operational regimes, and that some profile modification techniques and types of MHD activity produce characteristic trajectory changes. RP TAKAHASHI, H (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544, USA. NR 29 TC 2 Z9 2 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 MAY PY 1992 VL 32 IS 5 BP 815 EP 824 DI 10.1088/0029-5515/32/5/I08 PG 10 WC Physics, Fluids & Plasmas SC Physics GA HZ838 UT WOS:A1992HZ83800008 ER PT J AU WEYNANTS, RR VANOOST, G BERTSCHINGER, G BOEDO, J BRYS, P DELVIGNE, T DIPPEL, KH DURODIE, F EURINGER, H FINKEN, KH GRAY, DS HEY, JD HILLIS, DL HOGAN, JT KONEN, L LENERS, R MESSIAEN, AM POSPIESZCZYCK, A SAMM, U SCHORN, RP SCHWEER, B TELESCA, G VANNIEUWENHOVE, R VANDENPLAS, PE AF WEYNANTS, RR VANOOST, G BERTSCHINGER, G BOEDO, J BRYS, P DELVIGNE, T DIPPEL, KH DURODIE, F EURINGER, H FINKEN, KH GRAY, DS HEY, JD HILLIS, DL HOGAN, JT KONEN, L LENERS, R MESSIAEN, AM POSPIESZCZYCK, A SAMM, U SCHORN, RP SCHWEER, B TELESCA, G VANNIEUWENHOVE, R VANDENPLAS, PE TI CONFINEMENT AND PROFILE CHANGES INDUCED BY THE PRESENCE OF POSITIVE OR NEGATIVE RADIAL ELECTRIC-FIELDS IN THE EDGE OF THE TEXTOR TOKAMAK SO NUCLEAR FUSION LA English DT Article ID L-H TRANSITION; POLOIDAL ROTATION; PUMP LIMITER; TRANSPORT; BIFURCATION; HYDROGEN; PLASMAS; EXHAUST; MODEL AB Edge radial electric fields were induced in the edge of the TEXTOR tokamak by means of a polarization electrode in order to study their influence on the plasma edge profiles and its confinement. The studies include the generation of H-mode behaviour with either positive or negative polarity. Particle confinement (tau(p)) of deuterium and of impurity ions as well as energy confinement (tau(E)) are investigated. For positive fields which remain below the threshold for the L-H transition, an interesting regime of reduced particle confinement without noticeable energy confinement loss is found. A strong asymmetry in the edge density profiles with respect to the electric field sip is observed at these low polarization voltages. Above the threshold, H-mode behaviour with increased energy confinement and especially particle confinement can be produced with either polarity of the applied electric field. It is, however, found that, whereas the energy confinement in positive H-modes is at least as good as that in negative ones, the ratio tau(p)/tau(E) is about three times lower in the former case. C1 FORSCHUNGSZENTRUM JULICH, ASSOC EURATOM KFA, INST PLASMAPHYS, W-5170 JULICH 1, GERMANY. UNIV CALIF LOS ANGELES, INST PLASMA & FUS RES, LOS ANGELES, CA 90024 USA. OAK RIDGE NATL LAB, DIV FUS ENERGY, OAK RIDGE, TN 37831 USA. RP WEYNANTS, RR (reprint author), ECOLE ROYALE MIL, KONINKLIJKE MIL SCH, ASSOC EURATOM BELG STAAT, ASSOC EURATOM ETAT BELGE, BRUSSELS, BELGIUM. NR 26 TC 179 Z9 181 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 MAY PY 1992 VL 32 IS 5 BP 837 EP 853 DI 10.1088/0029-5515/32/5/I10 PG 17 WC Physics, Fluids & Plasmas SC Physics GA HZ838 UT WOS:A1992HZ83800010 ER PT J AU HOFMANN, F POMPHREY, N JARDIN, SC AF HOFMANN, F POMPHREY, N JARDIN, SC TI APPLICATION OF A NEW ALGORITHM TO PLASMA SHAPE CONTROL IN BPX SO NUCLEAR FUSION LA English DT Letter ID TOKAMAKS AB A new shape control algorithm has been tested by numerical simulation of a tokamak discharge in the Burning Plasma Experiment (BPX), using the TSC code. The algorithm controls the plasma shape and current according to a preprogrammed scenario without using any precalculated coil current waveforms. If the plasma parameters (heating scenario, density evolution, effective charge, etc.) change, the algorithm automatically maintains the given shape evolution and does not have to be readjusted. This allows independent programming of plasma current, density, heating power, shape and position. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544. RI Jardin, Stephen/E-9392-2010; pomphrey, neil/G-4405-2010 NR 7 TC 6 Z9 9 U1 0 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 MAY PY 1992 VL 32 IS 5 BP 897 EP 902 DI 10.1088/0029-5515/32/5/I14 PG 6 WC Physics, Fluids & Plasmas SC Physics GA HZ838 UT WOS:A1992HZ83800014 ER PT J AU HARRIS, JW ODYNIEC, G TONSE, S BOCK, R BROCKMANN, R RENFORDT, R ROLAND, G STOCK, R WENIG, S ALBER, T ECKARDT, V FESSLER, H KOWALSKI, M RAUCH, W SEYBOTH, J SEYBOTH, P SEYERLEIN, J AF HARRIS, JW ODYNIEC, G TONSE, S BOCK, R BROCKMANN, R RENFORDT, R ROLAND, G STOCK, R WENIG, S ALBER, T ECKARDT, V FESSLER, H KOWALSKI, M RAUCH, W SEYBOTH, J SEYBOTH, P SEYERLEIN, J TI 1ST EXPERIENCE WITH THE NA35-TPC IN HEAVY-ION COLLISIONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The NA35 collaboration has constructed a time projection chamber (TPC) with a sensitive volume of 240 x 125 x 112 cm3. The chamber is operated without a magnetic field and uses pad readout only. During the 1990 run with the S-32-beam at CERN 500k events were recorded. A description of the detector is given and the performance concerning the position measuring accuracy, two-track resolution, and particle identification by ionisation measurement is discussed. C1 GESELL SCHWERIONENFORSCH GMBH, W-6100 DARMSTADT 11, GERMANY. UNIV FRANKFURT, W-6000 FRANKFURT, GERMANY. MAX PLANCK INST PHYS & ASTROPHYS, W-8000 MUNICH 40, GERMANY. RP HARRIS, JW (reprint author), LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NR 6 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 33 EP 38 DI 10.1016/0168-9002(92)90676-U PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000006 ER PT J AU FRANKLIN, M FRY, A GAN, KK HAN, S KAGAN, H KANDA, S KANIA, D KASS, R KIM, SK MALCHOW, R MORROW, F OLSEN, S PALMER, WF PAN, LS SANNES, F SCHNETZER, S STONE, R SUGIMOTO, Y THOMSON, GB WHITE, C ZHAO, S AF FRANKLIN, M FRY, A GAN, KK HAN, S KAGAN, H KANDA, S KANIA, D KASS, R KIM, SK MALCHOW, R MORROW, F OLSEN, S PALMER, WF PAN, LS SANNES, F SCHNETZER, S STONE, R SUGIMOTO, Y THOMSON, GB WHITE, C ZHAO, S TI DEVELOPMENT OF DIAMOND RADIATION DETECTORS FOR SSC AND LHC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB Diamond is a nearly ideal material for use as a radiation detector in the high rate and high radiation environments of the SSC and LHC. The recent development of the chemical vapor deposition (CVD) method of diamond growth promises to make feasible the use of diamond in large quantities. We have carried out beam tests of various samples of CVD diamond supplied by several manufacturers and have measured signals from ionizing particles. Details of these measurements are presented. C1 SSC LAB,DEPT PHYS,DALLAS,TX 75237. OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. LAWRENCE LIVERMORE NATL LAB,DIV LASER,LIVERMORE,CA 94550. UNIV ROCHESTER,DEPT PHYS,ROCHESTER,NY 14627. RUTGERS STATE UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08854. KEK NAT LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 305,JAPAN. RP FRANKLIN, M (reprint author), HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138, USA. RI Kim, Sun Kee/G-2042-2015 OI Kim, Sun Kee/0000-0002-0013-0775 NR 8 TC 59 Z9 61 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 MAY 1 PY 1992 VL 315 IS 1-3 BP 39 EP 42 DI 10.1016/0168-9002(92)90677-V PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000007 ER PT J AU BARNETT, B BOSWELL, C MATTHEWS, J SKARHA, JE SNIDER, FD SPIES, A TSENG, J VEJCIK, S CARTER, H FLAUGHER, B GONZALES, B HRYCYK, M NELSON, C SEGLER, S SHAW, T TIPTON, P TKACZYK, S TURNER, K CARITHERS, WC ELY, R GOLD, M HABER, C HOLLAND, S KLEINFELDER, S MERRICK, T SCHNEIDER, O WESTER, W WONG, M AMIDEI, D DERWENT, PF BACCHETTA, N BISELLO, D BUSETTO, G CASTRO, A LORETI, M PESCARA, L BEDESCHI, F BOLOGNESI, V DELLAGNELLO, S GALEOTTI, S MARIOTTI, M MENZIONE, A PUNZI, G RAFFAELLI, F RISTORI, L TARTARELLI, F TURINI, N WENZEL, H ZETTI, F BAILEY, M GARFINKEL, AF SHAW, NM AF BARNETT, B BOSWELL, C MATTHEWS, J SKARHA, JE SNIDER, FD SPIES, A TSENG, J VEJCIK, S CARTER, H FLAUGHER, B GONZALES, B HRYCYK, M NELSON, C SEGLER, S SHAW, T TIPTON, P TKACZYK, S TURNER, K CARITHERS, WC ELY, R GOLD, M HABER, C HOLLAND, S KLEINFELDER, S MERRICK, T SCHNEIDER, O WESTER, W WONG, M AMIDEI, D DERWENT, PF BACCHETTA, N BISELLO, D BUSETTO, G CASTRO, A LORETI, M PESCARA, L BEDESCHI, F BOLOGNESI, V DELLAGNELLO, S GALEOTTI, S MARIOTTI, M MENZIONE, A PUNZI, G RAFFAELLI, F RISTORI, L TARTARELLI, F TURINI, N WENZEL, H ZETTI, F BAILEY, M GARFINKEL, AF SHAW, NM TI PROGRESS IN THE CONSTRUCTION OF THE CDF SILICON VERTEX DETECTOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB The mechanical design and construction progress of the CDF silicon vertex detector is described. Results on the location accuracy of the silicon strip detectors are presented and indicate an initial placement uncertainty of less than 10-mu-m. The water and gas cooling system, which is constructed of low mass materials and is used to remove heat from the readout electronics, is briefly described. Measurements of the performance of the silicon strip detectors are also given and show > 98.5% functioning strips for the assembled SVX detector. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV MICHIGAN,ANN ARBOR,MI 48109. UNIV PADUA,I-35100 PADUA,ITALY. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. PURDUE UNIV,W LAFAYETTE,IN 47907. RP BARNETT, B (reprint author), JOHNS HOPKINS UNIV,BALTIMORE,MD 21218, USA. RI Punzi, Giovanni/J-4947-2012; Holland, Stephen/H-7890-2013; Tartarelli, Giuseppe Francesco/A-5629-2016; OI Punzi, Giovanni/0000-0002-8346-9052; Tartarelli, Giuseppe Francesco/0000-0002-4244-502X; Turini, Nicola/0000-0002-9395-5230 NR 5 TC 6 Z9 6 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 MAY 1 PY 1992 VL 315 IS 1-3 BP 125 EP 132 DI 10.1016/0168-9002(92)90692-W PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000022 ER PT J AU GIUBELLINO, P PANIZZA, G HALL, G SOTTHIBANDHU, S ZIOCK, HJ FERGUSON, P SOMMER, WF EDWARDS, M CARTIGLIA, N HUBBARD, B LESLIE, J PITZL, D OSHAUGHNESSY, K ROWE, W SADROZINSKI, HFW SEIDEN, A SPENCER, E AF GIUBELLINO, P PANIZZA, G HALL, G SOTTHIBANDHU, S ZIOCK, HJ FERGUSON, P SOMMER, WF EDWARDS, M CARTIGLIA, N HUBBARD, B LESLIE, J PITZL, D OSHAUGHNESSY, K ROWE, W SADROZINSKI, HFW SEIDEN, A SPENCER, E TI STUDY OF THE EFFECTS OF NEUTRON-IRRADIATION ON SILICON STRIP DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA ID RADIATION-DAMAGE AB Silicon strip detectors and test structures were exposed to neutron fluences up to PHI = 6.1 x 10(14) n/cm2, using the ISIS neutron source at the Rutherford Appleton Laboratory (UK). In this paper we report some of our results concerning the effects of displacement damage, with a comparison of devices made of silicon of different resistivity. The various samples exposed showed a very similar dependence of the leakage current on the fluence received. We studied the change of effective doping concentration, and observed a behaviour suggesting the onset of type inversion at a fluence of approximately 2.0 x 10(13) n/cm2, a value which depends on the initial doping concentration. The linear increase of the depletion voltage for fluences higher than the inversion point could eventually determine the maximum fluence tolerable by silicon detectors. C1 UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON SW7 2AZ,ENGLAND. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064. RP GIUBELLINO, P (reprint author), IST NAZL FIS NUCL,TURIN,ITALY. OI Ferguson, Phillip/0000-0002-7661-4223 NR 17 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 156 EP 160 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000027 ER PT J AU BEDESCHI, F DELLAGNELLO, S GALEOTTI, S MARIOTTI, M MENZIONE, A PAOLETTI, R RAFFAELLI, F TARTARELLI, F TURINI, N ZETTI, F ELY, R GOLD, M HABER, C SCHINDLER, A SCHNEIDER, O WESTER, W WONG, M AMIDEI, D TIPTON, P TKACZYK, S CARTER, H HRYCYK, M BACCHETTA, N BISELLO, D BUSETTO, G LORETI, M PESCARA, L CASTRO, A BOSWELL, C SKARHA, J SNIDER, FD VEJCIK, S AF BEDESCHI, F DELLAGNELLO, S GALEOTTI, S MARIOTTI, M MENZIONE, A PAOLETTI, R RAFFAELLI, F TARTARELLI, F TURINI, N ZETTI, F ELY, R GOLD, M HABER, C SCHINDLER, A SCHNEIDER, O WESTER, W WONG, M AMIDEI, D TIPTON, P TKACZYK, S CARTER, H HRYCYK, M BACCHETTA, N BISELLO, D BUSETTO, G LORETI, M PESCARA, L CASTRO, A BOSWELL, C SKARHA, J SNIDER, FD VEJCIK, S TI SVX TEST BEAM RESULTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB An SVX sector prototype was operated at Fermilab in a configuration very close to the version to be installed in CDF. The sparse readout features of the SVXD chip [1,2], which provide the local data compaction that is necessary to deal with the detector high number of channels (40K) and typical Tevatron luminosities, were tested for the first time with a 230 GeV/c pion beam. A good background rejection and high hit efficiency was demonstrated in this mode of operation, with adequate signal to noise ratio and spatial resolution. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,PADUA,ITALY. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. RP BEDESCHI, F (reprint author), IST NAZL FIS NUCL,PISA,ITALY. RI Tartarelli, Giuseppe Francesco/A-5629-2016; OI Tartarelli, Giuseppe Francesco/0000-0002-4244-502X; Turini, Nicola/0000-0002-9395-5230 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 MAY 1 PY 1992 VL 315 IS 1-3 BP 188 EP 192 DI 10.1016/0168-9002(92)90702-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000032 ER PT J AU CLARK, AR GOOZEN, F GRUDBERG, P KLOPFENSTEIN, C KERTH, LT LOKEN, SC OLTMAN, E STROVINK, M TRIPPE, TG AF CLARK, AR GOOZEN, F GRUDBERG, P KLOPFENSTEIN, C KERTH, LT LOKEN, SC OLTMAN, E STROVINK, M TRIPPE, TG TI D0 VERTEX DRIFT CHAMBER CONSTRUCTION AND TEST-RESULTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA ID DETECTOR AB A jet-cell based vertex chamber has been built for the D0 experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO2(95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with [9.74 + 8.68(\E\ - 1.25)\ mu-m/ns where E is the electric field strength in kV/cm (1.0 kV/cm < \E\ < 1.6 kV/cm). An intrinsic spatial resolution of 60-mu-m or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630-mu-m. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP CLARK, AR (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 193 EP 196 DI 10.1016/0168-9002(92)90703-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000033 ER PT J AU ALPAT, B AMBROSI, G BARBAGLI, G BABUCCI, E BATTISTON, R BERTUCCI, B BILEI, GM BROOKS, M BURGER, WJ CARIA, M CASTELLINI, G CHECCUCCI, B CHEN, A COAN, TE COMMICHAU, V DONAT, A FIANDRINI, E GAU, SS HELLER, R HERVE, A HOFER, H LANDI, G LECOQ, P LEE, D LIN, WT MANTOVANI, G MILLS, GB NOWAK, H NOWAK, WD PAULUZZI, M POHL, M SANTOCCHIA, A SERVOLI, L TONISH, F VIERTEL, G WALDMEIER, S YEH, SC AF ALPAT, B AMBROSI, G BARBAGLI, G BABUCCI, E BATTISTON, R BERTUCCI, B BILEI, GM BROOKS, M BURGER, WJ CARIA, M CASTELLINI, G CHECCUCCI, B CHEN, A COAN, TE COMMICHAU, V DONAT, A FIANDRINI, E GAU, SS HELLER, R HERVE, A HOFER, H LANDI, G LECOQ, P LEE, D LIN, WT MANTOVANI, G MILLS, GB NOWAK, H NOWAK, WD PAULUZZI, M POHL, M SANTOCCHIA, A SERVOLI, L TONISH, F VIERTEL, G WALDMEIER, S YEH, SC TI THE DESIGN OF THE L3 SILICON MICROVERTEX DETECTOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB An upgrade of the L3 central tracking system, a silicon microvertex detector (SMD), is described. The detector consists of two layers of silicon, each equipped for r-phi and z readout with resolution almost-equal-to 6-mu-m and almost-equal-to 20-mu-m respectively. The SMD will provide full azimuthal coverage over the polar angular range 22-degrees less-than-or-equal-to theta less-than-or-equal-to 158-degrees. The total thickness is almost-equal-to 0.9% of one radiation length. C1 UNIV PERUGIA,I-06100 PERUGIA,ITALY. UNIV GENEVA,CH-1211 GENEVA 4,SWITZERLAND. NATL CENT UNIV,CHUNGLI,TAIWAN. INST HIGH ENERGY PHYS,BERLIN,GERMANY. RHEIN WESTFAL TH AACHEN,INST PHYS 3,W-5100 AACHEN,GERMANY. CERN,DIV PPE,CH-1211 GENEVA 23,SWITZERLAND. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. SWISS FED INST TECHNOL,INST HIGH ENERGY PHYS,CH-8092 ZURICH,SWITZERLAND. IST NAZL FIS NUCL,FLORENCE,ITALY. UNIV FLORENCE,I-50121 FLORENCE,ITALY. NATL TSING HUA UNIV,HSINCHU 300,TAIWAN. IROE,FLORENCE,ITALY. RP ALPAT, B (reprint author), IST NAZL FIS NUCL,PERUGIA,ITALY. RI Fiandrini, Emanuele/C-4549-2008; Servoli, Leonello/E-6766-2012; alpat, ali behcet/G-6290-2013; bertucci, bruna/J-5237-2012 OI Servoli, Leonello/0000-0003-1725-9185; alpat, ali behcet/0000-0002-0116-1506; NR 12 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 197 EP 200 DI 10.1016/0168-9002(92)90704-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000034 ER PT J AU ANASSONTZIS, E RESVANIS, L VOULGARIS, G YPSILANTIS, T TRIPP, R TORRES, S BIRAL, ARP CHINELLATO, JA TURTELLI, A CENCE, RJ HAYES, C HUDSON, J KELLEY, L LEARNED, JG PALUSELLI, D STENGER, VJ BARTOLI, B SINNIS, G WEEKES, D CRESTI, M PERUZZO, L PESCI, A SAGGION, A SARTORI, G LUKSYS, M ANGELINI, F BEDESCHI, F BELLAZZINI, R BERTOLUCCI, E CHIARELLI, G MARIOTTI, M MASSAI, MM MENZIONE, A SMITH, DA STEFANINI, A ZETTI, F CHUANG, KW KERRICK, A ONEIL, TJ TUMER, T ZYCH, AD BICCHI, P MEUCCI, M MOI, L PAOLETTI, R RIGATO, M SCRIBANO, A BUDINICH, M LIELLO, F MILOTTI, E AF ANASSONTZIS, E RESVANIS, L VOULGARIS, G YPSILANTIS, T TRIPP, R TORRES, S BIRAL, ARP CHINELLATO, JA TURTELLI, A CENCE, RJ HAYES, C HUDSON, J KELLEY, L LEARNED, JG PALUSELLI, D STENGER, VJ BARTOLI, B SINNIS, G WEEKES, D CRESTI, M PERUZZO, L PESCI, A SAGGION, A SARTORI, G LUKSYS, M ANGELINI, F BEDESCHI, F BELLAZZINI, R BERTOLUCCI, E CHIARELLI, G MARIOTTI, M MASSAI, MM MENZIONE, A SMITH, DA STEFANINI, A ZETTI, F CHUANG, KW KERRICK, A ONEIL, TJ TUMER, T ZYCH, AD BICCHI, P MEUCCI, M MOI, L PAOLETTI, R RIGATO, M SCRIBANO, A BUDINICH, M LIELLO, F MILOTTI, E TI A BACKGROUND-FREE DETECTOR FOR COSMIC-RAY SHOWERS IN THE ATMOSPHERE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB A detector of new design is planned to detect Cherenkov light in high energy cosmic ray showers. It is based on the detection of the middle-UV radiation by TMAE photosensitive chambers, giving detailed imaging of the shower, combined with the beneficial background screening of the ozone in the upper atmosphere. This allows us to greatly improve the duty-cycle, the sensitivity and the range of observations with respect to traditional Cherenkov experiments in the visible. A further advantage is the achievable big angular aperture which makes it possible to search for new sources with an efficiency similar to extensive air shower experiments. Details of the technique and achievable physics goals are presented. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV LOS ANDES,BOGOTA,COLOMBIA. CTR INT FIS,BOGOTA,COLOMBIA. UNIV ESTADUAL CAMPINAS,BR-13100 CAMPINAS,SP,BRAZIL. CNRQ,CAMPINAS,BRAZIL. UNIV HAWAII,HONOLULU,HI 96822. IST NAZL FIS NUCL,NAPLES,ITALY. NAPLES UNIV,I-80138 NAPLES,ITALY. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. IST NAZL FIS NUCL,PADUA,ITALY. CNRQ,PARAIBA,BRAZIL. UNIV PADUA,I-35100 PADUA,ITALY. UNIV PARAIBA,PARAIBA,BRAZIL. UNIV PISA,I-56100 PISA,ITALY. IST NAZL FIS NUCL,PISA,ITALY. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. UNIV SIENA,I-53100 SIENNA,ITALY. IST NAZL FIS NUCL,TRIESTE,ITALY. UNIV TRIESTE,I-34127 TRIESTE,ITALY. RP ANASSONTZIS, E (reprint author), UNIV ATHENS,ATHENS,GREECE. RI Chiarelli, Giorgio/E-8953-2012; Chinellato, Jose Augusto/I-7972-2012; OI Chiarelli, Giorgio/0000-0001-9851-4816; Chinellato, Jose Augusto/0000-0002-3240-6270; Milotti, Edoardo/0000-0001-7348-9765 NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 267 EP 271 DI 10.1016/0168-9002(92)90714-F PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000044 ER PT J AU SPADAFORA, AL AF SPADAFORA, AL TI TEST BEAM RESULTS FROM THE D0 LIQUID ARGON END CALORIMETER ELECTROMAGNETIC MODULE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB Results are presented from a test beam study of the D0 liquid argon end calorimeter electromagnetic module prior to its installation at the Fermilab Tevatron Collider. Using electron beams with energies ranging from 10-150 GeV we have obtained an energy resolution of 15.7%/square-root E(GeV) with a small constant term of 0.3% and a linearity of better than +/- 0.5%. The position resolution of the calorimeter is found to be approximately 1 mm for 100 GeV electrons. RP SPADAFORA, AL (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1992 VL 315 IS 1-3 BP 279 EP 284 DI 10.1016/0168-9002(92)90716-H PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000046 ER PT J AU AUBERT, B BAZAN, A BEAUGIRAUD, B CAVANNA, F COLAS, J LEBEAU, M LEFLOUR, T LEMAREC, JC MAIRE, M PETITPAS, P THION, J VIALLE, JP WINGERTERSEEZ, I GORDON, HA POLYCHRONAKOS, V RADEKA, V RAHM, D STEPHANI, D BAISIN, L BERSET, JC CHEVALLEY, JL FABJAN, CW FRANZ, A FARTHOUAT, P GILDEMEISTER, O JENNI, P LEFEBVRE, M MARIN, CP NESSI, M NESSITEDALDI, F PEPE, M POLESELLO, G RICHTER, W SIGRIST, A STEVENSON, GR WILLIS, WJ BAZE, JM GOSSET, L LAVOCAT, P MANSOULIE, B MEYER, JP RENARDY, JF TEIGER, J ZACCONE, H BATTISTONI, G CAMIN, D CAVALLI, D COSTA, G FERRARI, A GIANOTTI, F MANDELLI, L MAZZANTI, M PERINI, L PESSINA, G AUGE, E CHASE, RL CHOLLET, JC DELATAILLE, C FAYARD, L FOURNIER, D GUILHEM, G HRISOHO, A ICONOMIDOUFAYARD, L JEAN, P MERKEL, B NOPPE, JM PARROUR, G PETROFF, P REPELLIN, JP SCHAFFER, A SEGUIN, N VEILLET, JJ FUGLESANG, C AF AUBERT, B BAZAN, A BEAUGIRAUD, B CAVANNA, F COLAS, J LEBEAU, M LEFLOUR, T LEMAREC, JC MAIRE, M PETITPAS, P THION, J VIALLE, JP WINGERTERSEEZ, I GORDON, HA POLYCHRONAKOS, V RADEKA, V RAHM, D STEPHANI, D BAISIN, L BERSET, JC CHEVALLEY, JL FABJAN, CW FRANZ, A FARTHOUAT, P GILDEMEISTER, O JENNI, P LEFEBVRE, M MARIN, CP NESSI, M NESSITEDALDI, F PEPE, M POLESELLO, G RICHTER, W SIGRIST, A STEVENSON, GR WILLIS, WJ BAZE, JM GOSSET, L LAVOCAT, P MANSOULIE, B MEYER, JP RENARDY, JF TEIGER, J ZACCONE, H BATTISTONI, G CAMIN, D CAVALLI, D COSTA, G FERRARI, A GIANOTTI, F MANDELLI, L MAZZANTI, M PERINI, L PESSINA, G AUGE, E CHASE, RL CHOLLET, JC DELATAILLE, C FAYARD, L FOURNIER, D GUILHEM, G HRISOHO, A ICONOMIDOUFAYARD, L JEAN, P MERKEL, B NOPPE, JM PARROUR, G PETROFF, P REPELLIN, JP SCHAFFER, A SEGUIN, N VEILLET, JJ FUGLESANG, C TI LIQUID ARGON CALORIMETRY WITH LHC-PERFORMANCE SPECIFICATIONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA AB A novel geometry liquid argon calorimeter with accordion-shaped electrodes and converter plates has been recently conceived. Such a design allows for a fast readout and for a high granularity over large volumes with minimal dead spaces, properties which are considered essential for operation at the future hadron colliders. The first electromagnetic prototype based on this scheme has been built and tested at the CERN SPS. For a response peaking time of 140 ns an energy resolution of 10%/square-root E(GeV) and a space resolution of 4.4 mm/square-root E(GeV) with 2.7 cm cell size were achieved for electrons. A few preliminary results from a test with fast readout (response peaking time of less than 40 ns) are also presented. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. CERN,CH-1211 GENEVA 23,SWITZERLAND. CENS,F-91190 GIF SUR YVETTE,FRANCE. UNIV MILAN,I-20122 MILAN,ITALY. IST NAZL FIS NUCL,MILAN,ITALY. LAB ACCELERATOR LINEAIRE,ORSAY,FRANCE. MANNE SIEGBAHN INST,STOCKHOLM,SWEDEN. RP AUBERT, B (reprint author), LAB ANNECY LE VIEUX PHYS PARTICULES,ANNECY,FRANCE. OI Cavanna, Flavio/0000-0002-5586-9964; Pessina, Gianluigi Ezio/0000-0003-3700-9757 NR 10 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 MAY 1 PY 1992 VL 315 IS 1-3 BP 285 EP 293 DI 10.1016/0168-9002(92)90717-I PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000047 ER PT J AU DEBARBARO, P BODEK, A BUDD, RS FAN, Q SAKUMOTO, WK WINER, B PROUDFOOT, J UNDERWOOD, DG FOSTER, GW FREEMAN, J KIM, DH LIMON, PJ FUKUI, Y MISHINA, M BARNES, V APOLLINARI, G GIOKARIS, N GOULIANOS, K WHITE, S AF DEBARBARO, P BODEK, A BUDD, RS FAN, Q SAKUMOTO, WK WINER, B PROUDFOOT, J UNDERWOOD, DG FOSTER, GW FREEMAN, J KIM, DH LIMON, PJ FUKUI, Y MISHINA, M BARNES, V APOLLINARI, G GIOKARIS, N GOULIANOS, K WHITE, S TI RESEARCH-AND-DEVELOPMENT RESULTS ON SCINTILLATING TILE FIBER CALORIMETRY FOR THE CDF AND SDC DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5TH PISA MEETING ON ADVANCED DETECTORS : FRONTIER DETECTORS FOR FRONTIER PHYSICS CY MAY 26-31, 1991 CL ISOLA ELBA, ITALY SP ITALIAN PHYS SOC, EUROPEAN PHYS SOC, IST NAZL FIS NUCL, UNIV PISA ID READOUT AB We present results from R&D on scintillating tile calorimeters with wavelength-shifter-doped optical fiber readout. Studies of absolute light yields and measurements of spatial uniformity of response of various tile/fiber assemblies are described. Preliminary results on radiation hardness of the scintillating tile/fiber components are also presented. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. NATL LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 30032,JAPAN. PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907. ROCKEFELLER UNIV,DEPT PHYS,NEW YORK,NY 10021. RP DEBARBARO, P (reprint author), UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627, USA. NR 13 TC 16 Z9 16 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 MAY 1 PY 1992 VL 315 IS 1-3 BP 317 EP 321 DI 10.1016/0168-9002(92)90721-F PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HW330 UT WOS:A1992HW33000051 ER PT J AU JONES, KW SPANNE, P LINDQUIST, WB CONNER, WC FERRERO, M AF JONES, KW SPANNE, P LINDQUIST, WB CONNER, WC FERRERO, M TI DETERMINATION OF POLYMERIZATION PARTICLE MORPHOLOGY USING SYNCHROTRON COMPUTED MICROTOMOGRAPHY SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND EUROPEAN CONF ON ACCELERATORS IN APPLIED RESEARCH AND TECHNOLOGY ( ECAART 2 ) CY SEP 03-07, 1991 CL FRANKFURT MAIN, GERMANY SP BALZORS, BRUKER, BUNDESMINIST INNERDEUT BEZIEHUNGEN BONN, CERN, DAIMLER BENZ, DEUT FORSCHUNGSGEMEINSCH BONN, DEUT PHYS GESELL BAD HONNEF, EUROPEAN COMMUNITY BRUSSELS, HOECHST, UNIV FRANKFURT MAIN AB Polymerization of monomers over heterogeneous catalysts results in the fragmentation of the catalysts and subsequent transport in the polymer particles that are produced. Characterization of the process using nondestructive synchrotron computed microtomography techniques makes possible measurement of the distribution of the catalyst fragments in an individual particle and, in addition, gives an estimate of the particle porosity and surface area. The present experiment was carried out using the X-ray microscopy facility at the Brookhaven National Synchrotron Light Source (NSLS) X26 beam line. The tomographic sections were analyzed using autocorrelation techniques to determine porosity and surface area values. The results are compared to values obtained using conventional methods. This procedure makes possible the extraction of quantitative information about porosity and specific area from the tomograms. C1 SUNY STONY BROOK,STONY BROOK,NY 11794. UNIV MASSACHUSETTS,AMHERST,MA 01003. RP JONES, KW (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 10 TC 13 Z9 13 U1 1 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 MAY PY 1992 VL 68 IS 1-4 BP 105 EP 110 DI 10.1016/0168-583X(92)96059-8 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA JA788 UT WOS:A1992JA78800021 ER PT J AU JAMESON, RA LAWRENCE, GP BOWMAN, CD AF JAMESON, RA LAWRENCE, GP BOWMAN, CD TI ACCELERATOR-DRIVEN TRANSMUTATION TECHNOLOGY FOR INCINERATING RADIOACTIVE-WASTE AND FOR ADVANCED APPLICATION TO POWER PRODUCTION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND EUROPEAN CONF ON ACCELERATORS IN APPLIED RESEARCH AND TECHNOLOGY ( ECAART 2 ) CY SEP 03-07, 1991 CL FRANKFURT MAIN, GERMANY SP BALZORS, BRUKER, BUNDESMINIST INNERDEUT BEZIEHUNGEN BONN, CERN, DAIMLER BENZ, DEUT FORSCHUNGSGEMEINSCH BONN, DEUT PHYS GESELL BAD HONNEF, EUROPEAN COMMUNITY BRUSSELS, HOECHST, UNIV FRANKFURT MAIN AB Recent work at Los Alamos has revealed new techniques leading to greatly enhanced feasibility for using intense particle accelerators to drive systems for burning existing radioactive waste, and for electrical power generation with a much reduced waste stream in the future. The system requires the intense flux levels that can only be provided by an accelerator to exploit thermal energy neutrons for transmutation; thus the new physics of transmutation is different and more advanced than earlier ideas. Another key aspect affords the use of a dilute inventory system that reduces significantly the amount of fertile/fissile material required in the system at one time, with significant safety and engineering advantages. These concepts will be reviewed, and the requirements on the accelerator, which is on the order of 1.5 GeV, 50-250 mA continuous current, will be outlined. RP JAMESON, RA (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 14 TC 14 Z9 14 U1 1 U2 3 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 MAY PY 1992 VL 68 IS 1-4 BP 474 EP 480 DI 10.1016/0168-583X(92)96126-J PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA JA788 UT WOS:A1992JA78800088 ER PT J AU BENCH, G SAINT, A CHOLEWA, M LEGGE, GJF WEIRUP, DL PONTAU, AE AF BENCH, G SAINT, A CHOLEWA, M LEGGE, GJF WEIRUP, DL PONTAU, AE TI STIM TOMOGRAPHY - A 3-DIMENSIONAL HIGH-RESOLUTION IMAGING TOOL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND EUROPEAN CONF ON ACCELERATORS IN APPLIED RESEARCH AND TECHNOLOGY ( ECAART 2 ) CY SEP 03-07, 1991 CL FRANKFURT MAIN, GERMANY SP BALZORS, BRUKER, BUNDESMINIST INNERDEUT BEZIEHUNGEN BONN, CERN, DAIMLER BENZ, DEUT FORSCHUNGSGEMEINSCH BONN, DEUT PHYS GESELL BAD HONNEF, EUROPEAN COMMUNITY BRUSSELS, HOECHST, UNIV FRANKFURT MAIN ID TRANSMISSION ION MICROSCOPY; PROTON MICROPROBE; MICROTOMOGRAPHY; MICROBEAMS AB The ion microprobes now found in many accelerator laboratories were developed to perform quantitative elemental microanalysis with high sensitivity. The rapid evolution on this instrument of new computer based techniques has led to the development of high resolution quantitative 3D ion microtomography. This technique offers unique opportunities to examine internal structure of microscopic specimens. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. SANDIA NATL LABS,LIVERMORE,CA 94551. RP BENCH, G (reprint author), UNIV MELBOURNE,SCH PHYS,MICRO ANAL RES CTR,PARKVILLE,VIC 3052,AUSTRALIA. RI Cholewa, Marian/C-9474-2011 NR 23 TC 18 Z9 18 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1992 VL 68 IS 1-4 BP 481 EP 490 DI 10.1016/0168-583X(92)96127-K PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA JA788 UT WOS:A1992JA78800089 ER PT J AU FUNSTEN, HO MCCOMAS, DJ BARRACLOUGH, BL AF FUNSTEN, HO MCCOMAS, DJ BARRACLOUGH, BL TI THICKNESS UNIFORMITY AND PINHOLE DENSITY ANALYSIS OF THIN CARBON FOILS USING INCIDENT KEV IONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID OF-FLIGHT TECHNIQUE; SPACE AB The detection and characterization of thickness defects (nonuniformities and pinholes) in thin carbon foils is important in applications such as space-based particle analyzers. In this study we present a method of quantifying pinhole locations and sizes using scatter distributions of low energy ions which transit the foils. This technique, which we call transmitted ion mapping (TIM), is particularly suitable for analysis of ultrathin (less-than-or-equal-to 1-mu-g/cm2) foils in which thickness defects cannot be detected using optical microscopy due to foil transparency. Additionally, the foils are exposed to ion doses of less than 10(6) ions/cm2, so the method is nondestructive to the foils. As an illustration of this method, thickness nonuniformities and pinholes are examined in 0.2 and 0.5-mu-g/cm2 foils using incident 5 keV Ar+, Ne+, He+, and H+ ions. RP FUNSTEN, HO (reprint author), LOS ALAMOS NATL LAB,SPACE PLASMA PHYS GRP,LOS ALAMOS,NM 87545, USA. RI Funsten, Herbert/A-5702-2015 OI Funsten, Herbert/0000-0002-6817-1039 NR 24 TC 10 Z9 10 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 MAY PY 1992 VL 66 IS 4 BP 470 EP 478 DI 10.1016/0168-583X(92)95421-M PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HV597 UT WOS:A1992HV59700011 ER PT J AU ALTON, GD CARTER, HK LEE, IY JONES, CM KORMICKI, J OLSEN, DK AF ALTON, GD CARTER, HK LEE, IY JONES, CM KORMICKI, J OLSEN, DK TI STUDIES OF THE RELEASE PROPERTIES OF ISOL-TARGET MATERIALS USING ION-IMPLANTATION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID INTENSE BEAMS AB Experiments have been initiated which are designed to measure the time release characteristics of stable ion implanted species from selected refractory target materials which are potential candidates for forming radioactive beams at the proposed Oak Ridge Exotic Beam Facility (OREBF). The experiments are performed at the UNISOR facility by utilizing energetic HHIRF tandem accelerator ion beams to implant the species of interest into selected solid refractory target materials maintained at elevated temperatures within a FEBIAD-type ion source. In this report, we provide thermal time release data and estimates of efficiencies for releasing Cl from Zr5Si3 and As-75, Se-78 from Zr5Ge3. RP ALTON, GD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 17 TC 12 Z9 12 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 MAY PY 1992 VL 66 IS 4 BP 492 EP 502 DI 10.1016/0168-583X(92)95424-P PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HV597 UT WOS:A1992HV59700014 ER PT J AU YANG, WS FINCK, PJ KHALIL, H AF YANG, WS FINCK, PJ KHALIL, H TI RECONSTRUCTION OF PIN POWER AND BURNUP CHARACTERISTICS FROM NODAL CALCULATIONS IN HEXAGONAL-Z GEOMETRY SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID NEUTRON AB A reconstruction method is developed for recovering pin burnup characteristics from fuel cycle calculations performed in hexagonal-z geometry using the nodal diffusion option of the DIF3D/REBUS-3 code system. Intranodal distributions of group fluxes, nuclide densities, power density, burnup, and fluence are efficiently computed using polynomial shapes constrained to satisfy nodal information. The accuracy of the method is tested by performing several fast reactor numerical bench-mark calculations and by comparing predicted local burnups with values measured for experimental assemblies in the Experimental Breeder Reactor II. The results indicate that the reconstruction methods are quite accurate yielding maximum errors in power and nuclide densities that are < 2% for driver assemblies and typically < 5% for blanket assemblies. RP YANG, WS (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 16 TC 15 Z9 16 U1 0 U2 4 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAY PY 1992 VL 111 IS 1 BP 21 EP 33 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HR563 UT WOS:A1992HR56300002 ER PT J AU KIRK, BL AZMY, YY AF KIRK, BL AZMY, YY TI AN ITERATIVE ALGORITHM FOR SOLVING THE MULTIDIMENSIONAL NEUTRON DIFFUSION NODAL METHOD EQUATIONS ON PARALLEL COMPUTERS SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The one-group, steady-state neutron diffusion equation in two-dimensional Cartesian geometry is solved using the nodal integral method. The discrete variable equations comprise loosely coupled sets of equations representing the nodal balance of neutrons, as well as neutron current continuity along rows or columns of computational cells. An iterative algorithm that is more suitable for solving large problems concurrently is derived based on the decomposition of the spatial domain and is accelerated using successive overrelaxation. This algorithm is very well suited for parallel computers, especially since the spatial domain decomposition occurs naturally, so that the number of iterations required for convergence does not depend on the number of processors participating in the calculation. Implementation of our algorithm on the Intel IPSC/2 hypercube and Sequent Balance 8000 parallel computers is presented, and measured speedup and efficiency for test problems are reported. The results suggest that the efficiency of the hypercube quickly deteriorates when many processors are used, while the Sequent Balance retains very high efficiency for comparable number of participating processors. This leads to the conjecture that message-passing parallel computers are not as well suited for this algorithm as shared-memory machines. RP KIRK, BL (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAY PY 1992 VL 111 IS 1 BP 57 EP 65 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HR563 UT WOS:A1992HR56300005 ER PT J AU CRAMER, SN PEREY, FG AF CRAMER, SN PEREY, FG TI TIME-DEPENDENT MONTE-CARLO CALCULATIONS OF THE OAK-RIDGE ELECTRON LINEAR-ACCELERATOR TARGET NEUTRON-SPECTRUM SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The time-dependent spectrum of neutrons in the water-moderated Oak Ridge Electron Linear Accelerator (ORELA) target is calculated using a modified version of the MORSE multigroup Monte Carlo code with an analytic hydrogen scattering model. Distributions of effective neutron distance traversed in the target are estimated with a time- and energy-dependent algorithm from the leakage normal to the target face. The 10-eV to 20-MeV energy range is adequately represented in the MORSE code by the 174-group VITAMIN-E cross-section library with a P5 expansion. An approximate representation of the ORELA positron source facility, recently installed near the target, is included in the calculations to determine any perturbations the positron source might create in the computed neutron distributions from the target. A series of coupled Monte Carlo calculations is performed from the target to the positron source ard back to the target using a next-event estimation surface source for each step. The principal effect of the positron source is an increase in the distance for the lower energy neutron spectra, producing no real change in the distributions where the ORELA source is utilized for experiments. Different configurations for the target are investigated to simulate the placement of a shadow bar in the neutron beam. These beam configurations include neutrons escaping from (a) the central tantalum plates only, (b) the entire target with the tantalum plates blocked out, and (c) only a small area from the water. Comparisons of the current data with previous calculations having a less detailed model of the tantalum plates are satisfactory. RP CRAMER, SN (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 6 TC 3 Z9 3 U1 0 U2 3 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAY PY 1992 VL 111 IS 1 BP 102 EP 111 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HR563 UT WOS:A1992HR56300008 ER PT J AU HOHORST, JK ALLISON, CM AF HOHORST, JK ALLISON, CM TI DF-4 ANALYSIS USING SCDAP RELAP5 SO NUCLEAR TECHNOLOGY LA English DT Article DE SCDAP RELAP5; DF-4; DAMAGE PROGRESSION AB The SCDAP/RELAP5 severe accident analysis computer code, developed at the Idaho National Engineering Laboratory, is used to analyze the fourth in a series of debris formation experiments. The debris formation-four (DF-4) experiment deals with heatup and meltdown of a boiling water reactor (BWR)-representative fuel and control blade assembly segment, performed in the Annular Core Research Reactor at Sandia National Laboratories. The DF-4 experiment provides data that are used to validate core damage progression and BWR-specific models to gain an understanding of the phenomena occurring in the bundle during a severe BWR accident and to identify additional modeling needed in severe accident codes. The SCDAP/RELAP5 model used for this analysis accurately predicts the key damage events, which include control blade melting, channel box relocation and runaway oxidation, the order and timing of these events, and the maximum bundle temperature. From these analytical calculations, an accident scenario and insights into phenomena occurring during a severe BWR accident are developed. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAY PY 1992 VL 98 IS 2 BP 149 EP 159 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HP639 UT WOS:A1992HP63900002 ER PT J AU SANDOVAL, RP EINZIGER, RE JORDAN, H MALINAUSKAS, AP MINGS, WJ AF SANDOVAL, RP EINZIGER, RE JORDAN, H MALINAUSKAS, AP MINGS, WJ TI ESTIMATE OF THE CRUD CONTRIBUTION TO SHIPPING CASK CONTAINMENT REQUIREMENTS SO NUCLEAR TECHNOLOGY LA English DT Article DE SPENT FUEL; TRANSPORTATION CASKS; CRUD AB A methodology is developed to relate U.S. Code of Federal Regulations, Title 10, Part 71 (10CFR71) containment requirements to leak rates for the special case in which the only radioactive species having a potential for escape from the cask is that associated with debris ("crud") contained on the fuel assemblies being transported. The methodology accounts for the characteristics of the crud and for attenuation of the gas-borne crud particulates once they become suspended within the cask. Calculations are performed for typical spent-fuel transport cask geometries and the normal and accident conditions prescribed in 10CFR71. The most current published data are used for crud composition and structure, specific activity, spallation mechanics and fractions, and crud particle size. The containment criteria leak rates are calculated assuming 5-yr-old spent fuel. In each accident case, the containment leak rate criteria are well in excess of 10 cm3/s. Under normal conditions of transport, the regulatory containment requirements are met by leak rates ranging from 1.5 x 10(-3) cm3/s to 1.5 x 10(-4) cm3/s for the transport of boiling water reactor fuel assemblies and from 1.8 x 10(-2) cm3/s to 1.3 x 10(-3) cm3/s for pressurized water reactor fuel assemblies. The calculated leak rates are most sensitive to the cask design, type of fuel, and particle size distribution. Conservatism of the limiting leak rates is discussed. C1 PACIFIC NW LAB, MAT APPLICAT SECT, RICHLAND, WA 99352 USA. EG&G, DEV SAFETY ANAL METHODS GRP, GOLDEN, CO 80402 USA. US NUCL REGULATORY COMMISS PROGRAMS, WASHINGTON, DC USA. OAK RIDGE NATL LAB, CHEM DEV SECT, OAK RIDGE, TN 37831 USA. IDAHO NATL ENGN LAB, IDAHO FALLS, ID USA. RP SANDOVAL, RP (reprint author), SANDIA NATL LABS, YUCCA MT NUCL WASTE REPOSITORY DEPT, ALBUQUERQUE, NM 87185 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAY PY 1992 VL 98 IS 2 BP 196 EP 206 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HP639 UT WOS:A1992HP63900007 ER PT J AU SCHWEITZER, DG AF SCHWEITZER, DG TI CONSEQUENCES OF INSTABILITY AND NONSTOICHIOMETRY IN HIGH-TEMPERATURE NUCLEAR-FUELS SO NUCLEAR TECHNOLOGY LA English DT Note DE THERMODYNAMICS; PHASE EQUILIBRIA; SPACE PROPULSION AB The search for high-temperature nuclear fuels is based on obtaining melting-point data from binary and ternary phase relationships. Arguments are presented that properties of important high-temperature materials used in nuclear fuels and fuel-element protective coatings have been obtained from nonequilibrium-phase diagrams and that the materials themselves are thermodynamically unstable. These data are time dependent and should be used with caution. Multicomponent solids at high temperatures have defect-stabilized equilibrium structures that can exhibit large deviations from stoichiometry. The properties of these materials are consistent with the view that the compound acts as a solvent for the individual consituents whose activities are dependent on the overall composition of the solid solution and on the environment when the environment includes a gas containing one or more of the constituents in the solid. At high temperatures, almost all stoichiometric refractory carbides and nitrides are unstable and evaporate incongruently. In closed systems, incongruently evaporating materials eventually achieve stable configurations that are inherently mass dependent and geometry dependent. These mass-dependent, geometry-dependent properties include melting temperatures. Many nonequilibrium stoichiometric compounds yield apparent melting points when heated rapidly while exhibiting incongruent vaporization hundreds of degrees below the reported melting points. Experiments show that the composition of nonstoichiometric single phase solids that are in equilibrium with the same vapor composition can differ from the nonequilibrium time-dependent stoichiometric melting compositions by > 50%. Equilibrium compositions of nonstoichiometric nuclear fuels and fuel coatings are temperature dependent. The materials exhibit a wide range of evaporation rates at high temperatures. They undergo time-dependent compositional and structural changes when subjected to temperature cycles and temperature gradients. Such changes can lead to complex reactivity differences in gas environments and the development of time-varying internal stresses that are position dependent and composition dependent. Such effects limit the performance of high-temperature fuels. Understanding the theoretical causes of these effects is important in their minimization. Minimization of the effects is important in reducting the degradation rates of both nuclear fuels and protective coatings. RP SCHWEITZER, DG (reprint author), BROOKHAVEN NATL LAB,DEPT NUCL ENERGY,UPTON,NY 11973, USA. NR 30 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAY PY 1992 VL 98 IS 2 BP 245 EP 252 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA HP639 UT WOS:A1992HP63900013 ER PT J AU MOLLEY, PA KAST, BA AF MOLLEY, PA KAST, BA TI AUTOMATIC TARGET RECOGNITION AND TRACKING USING AN ACOUSTOOPTIC IMAGE CORRELATOR SO OPTICAL ENGINEERING LA English DT Article DE INFORMATION PROCESSING; OPTICAL PATTERN RECOGNITION; CORRELATORS; ACOUSTOOPTICS, HYBRID RECOGNITION SYSTEMS; TARGET TRACKING AB A hybrid electro-optic image processor has been developed for automatic target recognition and tracking using an acousto-optic correlator and digital electronics., The optical system performs the computationally intensive correlation operation on the large 2-D input scenes. The electronics provide the decision-making capability and also perform part of the postprocessing needed for increasing the peak-to-clutter ratio in cluttered scenes. The system is able to analyze each correlation plane and apply a real-time template selection.algorithm to accommodate scale or rotation changes of the target. A demonstration of the current system capabilities is presented using a terrain board with several different types of stationary and moving model vehicles. RP MOLLEY, PA (reprint author), SANDIA NATL LABS,DIV 1415,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAY PY 1992 VL 31 IS 5 BP 956 EP 962 DI 10.1117/12.57505 PG 7 WC Optics SC Optics GA HU370 UT WOS:A1992HU37000011 ER PT J AU DERI, RJ PENNINGS, ECM HAWKINS, RJ AF DERI, RJ PENNINGS, ECM HAWKINS, RJ TI QUENCHING OF RESONANTLY ENHANCED ABSORPTION BY MULTIMODE INTERFERENCE IN VERTICALLY COUPLED WAVE-GUIDE PHOTODETECTORS SO OPTICS LETTERS LA English DT Article ID PIN PHOTODIODE; WAVE-GUIDES; INTEGRATION AB We show that the resonantly enhanced absorption predicted for conventional vertically coupled waveguide photodetectors by steady-state eigenanalysis can overestimate detector absorption (waveguide-to-detector coupling efficiency) owing to modal power nonorthogonality. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP DERI, RJ (reprint author), BELLCORE,331 NEWMAN SPRINGS RD,RED BANK,NJ 07701, USA. NR 16 TC 7 Z9 7 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 1 PY 1992 VL 17 IS 9 BP 667 EP 669 DI 10.1364/OL.17.000667 PG 3 WC Optics SC Optics GA HP328 UT WOS:A1992HP32800013 PM 19794592 ER PT J AU FOO, T BERGMAN, RG AF FOO, T BERGMAN, RG TI SYNTHESIS AND C-H ACTIVATION REACTIONS OF (MU-5-INDENYL)(TRIMETHYLPHOSPHINE)IRIDIUM ALKYL AND HYDRIDE COMPLEXES SO ORGANOMETALLICS LA English DT Article ID CARBON-HYDROGEN-BONDS; METAL-SILYL COMPLEXES; SLIP-FOLD DISTORTION; R = H; MOLECULAR-STRUCTURES; INDENYL COMPLEXES; SUBSTITUTION-REACTIONS; REACTION CHEMISTRY; CRYSTAL-STRUCTURE; RHODIUM COMPLEX AB To obtain C-H oxidative addition products susceptible to further chemical transformation, the synthesis of a series of indenyliridium complexes that parallel the pentamethylcyclopentadienyl systems shown earlier to successfully activate alkane carbon-hydrogen bonds has been developed. Efficient routes to several members of the series (eta-5-C9H7)Ir(PMe3)(X)(Y), where X and Y are alkyl, aryl, and hydride ligands, are described. The structure of the (methyl)(phenyl)iridium complex (eta-5-C9H7)Ir(PMe3)(CH3)(Ph) (4b) has been determined by X-ray diffraction: space group P2(1)/c with a = 7.6688 (6) angstrom, b = 18.5650 (16) angstrom, c = 12.3855 (9) angstrom, alpha = 90.0-degrees, beta = 98.674 (7)-degrees, gamma = 90.0-degrees, and Z = 4; R = 0.0164; R(W) = 0.0223 on the basis of 1972 data having F(o)2 > 3-sigma(F(o)2). In spite of the increased lability of these complexes caused by the presence of the indenyl ligand, they retain both the thermal and photochemical C-H activating properties associated with the corresponding pentamethylcyclopentadienyl complexes. Thus (eta-5-C9H7)Ir(PMe3)H2 (7) undergoes loss of H2 on irradiation and in benzene and cyclohexane solvent leads to (eta-5-C9H7)Ir(PMe3)(C6H5)(H) (6b) and (eta-5-C9H7)Ir(PMe3)(C6H11)(H) (6d), respectively. Thermolysis of (eta-5-C9H7)Ir(PMe3)(CH3)(H) (6a) occurs to eliminate methane at a temperature lower than that for the Cp* analogue and in benzene and cyclohexane once again leads successfully to the phenyl and cyclohexyl hydrides 6b and 6d. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. NR 58 TC 44 Z9 44 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD MAY PY 1992 VL 11 IS 5 BP 1801 EP 1810 DI 10.1021/om00041a013 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA HT861 UT WOS:A1992HT86100013 ER PT J AU FOO, T BERGMAN, RG AF FOO, T BERGMAN, RG TI MIGRATORY INSERTION REACTIONS OF INDENYLIRIDIUM DIALKYLS AND ALKYL AND ARYL HYDRIDES SO ORGANOMETALLICS LA English DT Article ID CARBON-HYDROGEN-BONDS; INDUCED REDUCTIVE ELIMINATION; CRYSTAL-STRUCTURE; RHODIUM COMPLEX; ACTIVATION; REACTIVITY; CARBONYLATION; SUBSTITUTION; INTERMEDIATE; CHEMISTRY AB This paper reports the migratory insertion chemistry of indenyliridium complexes described in the companion paper. Complexes of general formula (eta-5-Ind)(PMe3)Ir(R)(R'), where R = alkyl or aryl and R' = alkyl, aryl, or hydride (4-6) react with dative ligands L such as tert-butylisocyanide and CO. These transformations lead to eta-5 to eta-1 isomerization of the indenyl ligand, giving octahedral iridium complexes of general formula (eta-1-Ind)(PMe3)(L)2Ir(R)(R') (8, 9, 11). Treatment of the methyl aryl and dimethyl eta-1-indenyl complexes 9a, 9d, and 9e with trimethylamine oxide removes CO, allowing the indenyl ligand to reestablish eta-5-coordination by inducing CO migratory insertion to give acyl complexes 10. Reaction of eta-1-indenyl aryl and methyl hydrides 6 (as well as the dihydride (eta-5-Ind)(PMe3)IrH2 (7)) with CO leads to reductive elimination of arene, methane, or H-2 rather than migratory insertion, forming (eta-1-Ind)(CO)3(PMe3)Ir (12) as the organometallic product. In contrast, treatment of methyl and aryl hydrides 6 with alkynes leads to the methyl vinyl complexes (eta-5-Ind)(PMe3)Ir(Me)(CR=C(R')(H)) (13) and reaction of 6a with ethylene gives the methyl ethyl complex (eta-5-Ind)(PMe3)Ir(Me)(Et) (14). Isotope labeling, stereochemical, and kinetic studies have been carried out on the insertion reaction of 6a with 3,3-di-methyl-1-butyne. The results of these experiments are most consistent with a mechanism involving initial reversible coordination of alkyne to the metal center (probably with concurrent eta-5-eta-3 isomerization of the indenyl ligand) followed by irreversible migration of the metal-bound hydrogen to the tert-butyl-substituted carbon of the alkyne and then rapid recoordination of the indenyl group. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. NR 49 TC 42 Z9 42 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD MAY PY 1992 VL 11 IS 5 BP 1811 EP 1819 DI 10.1021/om00041a014 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA HT861 UT WOS:A1992HT86100014 ER PT J AU PHILLIPS, DG COOKE, JA ANDERSON, AE AF PHILLIPS, DG COOKE, JA ANDERSON, AE TI A SUREFIRE RESOLUTION TO WORKPLACE CONFLICTS SO PERSONNEL JOURNAL LA English DT Article RP PHILLIPS, DG (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV HUMAN RESOURCES DEV,EMPLOYEE RELAT GRP,LOS ALAMOS,NM 87544, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ACC COMMUNICATIONS INC PI COSTA MESA PA 245 FISCHER AVE, COSTA MESA, CA 92626 SN 0031-5745 J9 PERS J JI Pers. J. PD MAY PY 1992 VL 71 IS 5 BP 111 EP 114 PG 4 WC Psychology, Applied SC Psychology GA HT387 UT WOS:A1992HT38700012 ER PT J AU BRUEMMER, SM CHARLOT, LA BRIMHALL, JL HENAGER, CH HIRTH, JP AF BRUEMMER, SM CHARLOT, LA BRIMHALL, JL HENAGER, CH HIRTH, JP TI DISLOCATION-STRUCTURES IN BE12NB AFTER HIGH-TEMPERATURE DEFORMATION SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article AB Dislocation structures and faults in vacuum-hot-pressed Be12Nb have been examined after compressive deformation at 1200-degrees-C. Both perfect and partial dislocations were observed in the deformed polycrystalline material. Most dislocations were found to be partials bounding planar faults in the grains characterized. Slip systems for individual partial dislocations were identified as 1/2<101]{121), 1/2<101]{101) and 1/2<100]{011). Several faults were bounded by identical 1/2<101] or 1/2<100] dislocations. Extended planar {101) faults created by emission of a single 1/2<101] partial from grain or twin boundaries were seen in both the vacuum-hot-pressed and deformed conditions. Perfect dislocations in the deformed microstructure were 1/2<111]{101) and 1/2<111]{121), with some evidence for <001]{100] and <101]{101) dislocations. The partial dislocations are related to a possible phase transformation from Be12Nb to Be17Nb2 which may enhance dislocation mobility and promote high-temperature deformation. C1 WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA. RP BRUEMMER, SM (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. OI Henager, Chuck/0000-0002-8600-6803 NR 15 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD MAY PY 1992 VL 65 IS 5 BP 1083 EP 1094 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA HX881 UT WOS:A1992HX88100005 ER PT J AU GAO, Y MERKLE, KL CHANG, HL ZHANG, TJ LAM, DJ AF GAO, Y MERKLE, KL CHANG, HL ZHANG, TJ LAM, DJ TI STUDY OF DEFECTS AND INTERFACES ON THE ATOMIC SCALE IN EPITAXIAL TIO2 THIN-FILMS ON SAPPHIRE SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; MATERIALS-SCIENCE; GROWTH; RUTILE AB TiO2 thin films grown on (1120BAR) sapphire (alpha-Al2O3) at 800-degrees-C by the metallo-organic chemical vapour deposition technique have been characterized by transmission electron microscopy. The TiO2 thin films are single-crystal rutile. The epitaxial orientation relationship between the rutile thin films (R) and the sapphire substrates (S) is (101)[001]R parallel-to (1120BAR)[0001]S. Growth twins are commonly observed in the films with (101) twin planes and <101> twinning directions. The atomic structure of twin boundaries and TiO2-alpha-Al2O3 interfaces have been investigated by high-resolution electron microscopy. When the interfaces are viewed in the direction of [010]R-[0001]S, the interfaces appear structurally coherent along the direction of [101BAR]R-[1100BAR]S. The small misfit (0.5%) is accommodated at interface steps. In contrast, in the direction of [101BAR]R-[1100BAR]S, the interfaces are semicoherent. Growth mechanisms are discussed, based on information about the atomic structure of the interfaces. RP GAO, Y (reprint author), ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 28 TC 23 Z9 23 U1 1 U2 8 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD MAY PY 1992 VL 65 IS 5 BP 1103 EP 1125 PG 23 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA HX881 UT WOS:A1992HX88100007 ER PT J AU SKJERPE, P OLSEN, A TAFTO, J SUENAGA, M ZHU, Y MOODENBAUGH, AR AF SKJERPE, P OLSEN, A TAFTO, J SUENAGA, M ZHU, Y MOODENBAUGH, AR TI TETRAGONAL YBA2(CU1-XMX)3O7+DELTA, M = FE, CO, AL, TWEED CONTRAST AND ORTHORHOMBIC MICROTWINS SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID YBA2CU3O7-DELTA; YBA2(CU1-XFEX)3O7-DELTA; SUPERCONDUCTIVITY; DIFFRACTION; NEUTRON AB Calculations predict that orthorhombic microtwins of the same orthorhombicity as pure YBa2Cu3O7-delta result in an apparent tetragonal symmetry in diffraction experiments when the twin period is reduced below about 20 nm. The diffuse electron scattering observed around the fundamental reflections from YBa2(CU1-xMx)3O7+delta, where M=Fe, Al, or Co and x greater-than-or-similar-to 0.03, is also well described by this model of non-periodic orthorhombic microtwins, suggesting that these trivalent cations on the chain sites promote the formation of chemical twins. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP SKJERPE, P (reprint author), UNIV OSLO,DEPT PHYS,OSLO 3,NORWAY. OI Moodenbaugh, Arnold/0000-0002-3415-6762 NR 20 TC 7 Z9 7 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD MAY PY 1992 VL 65 IS 5 BP 1067 EP 1077 DI 10.1080/13642819208217921 PG 11 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA HX880 UT WOS:A1992HX88000013 ER PT J AU BIRNBAUM, D SELTZER, S AF BIRNBAUM, D SELTZER, S TI A HIGHLY REACTIVE HETEROATOM ANALOG OF RETINAL AND ITS INTERACTION WITH BACTERIORHODOPSIN SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID CIS-TRANS ISOMERIZATION; PURPLE MEMBRANE; SCHIFF-BASE; RHODOPSIN; SPECTROSCOPY; MODEL; HALORHODOPSIN; HALOBACTERIA; SUBSTITUTION; RESOLUTION AB C18 formate ester (5) [2-(6-methyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3E,5E,7E-octatrienyl formate], a highly reactive analog of retinal, was synthesized and its interaction with bacterioopsin studied. The formate ester, in the absence of purple or bleached membrane, undergoes very rapid reaction (t1/2 = 0.9 min) in neutral buffer but with membrane present it diffuses more rapidly into the membrane where it reacts slowly. incorporation of 5 in the membrane results in a 38 nm (3900 cm-1) red shift which remains after reconstitution with retinal. Similar experiments with the corresponding C18 alcohol (4) results in a red shift, but this absorption blue shifts upon reconstitution with retinal. Washing the formate ester-treated membrane with bovine serum albumin or the corresponding lyophilized preparation with hexane, treatments that remove retinal oxime, fails to remove the UV-visible absorption, suggesting that a covalent bond between the C18 moiety and a nucleophilic group of the protein has probably formed. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. NR 40 TC 4 Z9 4 U1 0 U2 1 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD MAY PY 1992 VL 55 IS 5 BP 745 EP 752 PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA HR928 UT WOS:A1992HR92800017 ER PT J AU KONJEVIC, R KHURANA, JP POFF, KL AF KONJEVIC, R KHURANA, JP POFF, KL TI ANALYSIS OF MULTIPLE PHOTORECEPTOR PIGMENTS FOR PHOTOTROPISM IN A MUTANT OF ARABIDOPSIS-THALIANA SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SEEDLINGS; LIGHT AB The shape of the fluence-response relationship for the phototropic response of the JK224 strain of Arabidopsis thaliana depends on the fluence rate and wavelength of the actinic light. At low fluence rate (0.1-mu-mol m-2s-1), the response to 450-nm light is characterized by a single maximum at about 9-mu-mol m-2. At higher fluence rate (0.4-mu-mol m-2s-1), the response shows two maxima, at 4.5 and 9-mu-mol m-2. The response to 510-nm light shows a single maximum at 4.5-mu-mol m-2. Unilateral preirradiation with high fluence rate (25-mu-mol m-2s-1) 510-nm light eliminates the maximum at 4.5-mu-mol m-2 in the fluence response curve to a subsequent unilateral 450-nm irradiation, while the second maximum at 9-mu-mol m-2 is unaffected. Based on these results, it is concluded that a single photoreceptor pigment has been altered in the JK224 strain of Arabidopsis thaliana. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. FU NIDCR NIH HHS [DE-AC02-76ERO-1338] NR 16 TC 18 Z9 19 U1 0 U2 2 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD MAY PY 1992 VL 55 IS 5 BP 789 EP 792 PG 4 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA HR928 UT WOS:A1992HR92800022 PM 11536505 ER PT J AU HANSON, DK NANCE, SL SCHIFFER, M AF HANSON, DK NANCE, SL SCHIFFER, M TI 2ND-SITE MUTATION AT M43 (ASN-]ASP) COMPENSATES FOR THE LOSS OF 2 ACIDIC RESIDUES IN THE Q(B) SITE OF THE REACTION CENTER SO PHOTOSYNTHESIS RESEARCH LA English DT Note DE ELECTRON TRANSFER; PROTON TRANSFER; PHOTOSYNTHESIS; QUINONE; REACTION CENTER; SITE-SPECIFIC MUTAGENESIS; SUPPRESSOR MUTATIONS ID PHOTOSYNTHETIC REACTION-CENTER; BACTERIAL REACTION CENTERS; RHODOPSEUDOMONAS-CAPSULATA; RHODOBACTER-SPHAEROIDES; L-SUBUNIT; PROTON-TRANSFER; CHLOROFLEXUS-AURANTIACUS; ELECTRON-TRANSFER; PURPLE BACTERIUM; QUINONE AB Two acidic residues, L212Glu and L213Asp, in the Q(B) binding sites of the photosynthetic reaction centers of Rhodobacter capsulatus and Rhodobacter sphaeroides are thought to play central roles in the transfer of protons to the quinone anion(s) generated by photoinduced electron transfer. We constructed the site-specific double mutant L212Ala-L213Ala in R. capsulatus, that is incapable of growth under photosynthetic conditions. A photocompetent derivative of that strain has been isolated that carries the original L212Ala-L213Ala double mutation and a second-site suppressor mutation at residue M43 (Asn --> Asp), outside of the Q(B) binding site, that is solely responsible for restoring the photosynthetic phenotype. The Asp,Asn combination of residues at the L213 and M43 positions is conserved in the five species of photosynthetic bacteria whose reaction center sequences are known. In R. capsulatus and R. sphaeroides, the pair is L213Asp-M43Asn. But, the reaction centers of Rhodopseudomonas viridis, Rhodospirillum rubrum and Chloroflexus aurantiacus reverse the combination to L213Asn-M43Asp. In this respect, the Q(B) site of the suppressor strain resembles that of the latter three species in that it couples an uncharged residue at L213 with an acidic residue at M43. These reaction centers, in which L213 is an amide, must employ an alternative proton transfer pathway. The observation that the M43Asn --> Asp mutation in R. capsulatus compensates for the loss of both acidic residues at L212 and L213 suggests that M43Asp is involved in a new proton transfer route in this species that resembles the one normally used in reaction centers of Rps. viridis, Rsp. rubrum and C. aurantiacus. RP HANSON, DK (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 31 TC 34 Z9 34 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0166-8595 J9 PHOTOSYNTH RES JI Photosynth. Res. PD MAY PY 1992 VL 32 IS 2 BP 147 EP 153 DI 10.1007/BF00035949 PG 7 WC Plant Sciences SC Plant Sciences GA JB495 UT WOS:A1992JB49500007 PM 24408285 ER PT J AU BAYM, G EPSTEIN, RI LINK, B AF BAYM, G EPSTEIN, RI LINK, B TI DYNAMICS OF VORTICES IN NEUTRON-STARS SO PHYSICA B LA English DT Article; Proceedings Paper CT KORBER SYMP ON SUPERFLUID HE-3 IN ROTATION CY JUN 10-14, 1991 CL ESPOO, FINLAND SP ACAD FINLAND, FOREIGN MINIST FINLAND, COMMISS SCI & TECH COLLABORAT BETWEEN FINLAND & SOV, IET UNION, KORBER STIFT, NORDIC INST THEORET ATOM PHYS, N HOLLAND PUBL, UNIV HELSINKI, RES INST THEORET PHYS, WALDEMAR VON FRECKELLS STIFTELSE ID ROTATING SUPERFLUIDS; PULSAR GLITCHES; TEMPERATURE; HYDRODYNAMICS AB Neutron stars present an interesting challenge to low temperature physics: to understand the processes responsible for the sudden speed-ups, or "glitches", observed in many pulsars. Interactions between the neutron superfluid and thc neutron rich nuclei in the inner crust of neutron stars are likely responsible for glitches, post-glitch relaxations and other timing irregularities. Here we describe recent work on thc physics on these interactions and how they give rise to vortex pinning, vortex creep, and thc dissipative coupling between the superfluid and the crust. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP BAYM, G (reprint author), UNIV ILLINOIS,LOOMIS LAB PHYS,1110 W GREEN ST,URBANA,IL 61801, USA. NR 29 TC 28 Z9 28 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 1992 VL 178 IS 1-4 BP 1 EP 12 DI 10.1016/0921-4526(92)90173-P PG 12 WC Physics, Condensed Matter SC Physics GA JA629 UT WOS:A1992JA62900003 ER PT J AU LAM, QH JEFFRIES, CD AF LAM, QH JEFFRIES, CD TI DEPENDENCE OF COMPLEX PERMEABILITY AND HARMONIC POWER-GENERATION OF A SINTERED YBA2CU3O7-DELTA ROD ON APPLIED AC AND DC MAGNETIC-FIELDS SO PHYSICA C LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; BA-CU-O; CRITICAL-STATE MODEL; NONLINEAR ELECTRODYNAMICS; OXIDES AB Systematic experimental studies are reported for the AC permeability and harmonic generation power P(nf) in a sintered rod of granular YBa2Cu3O7-delta at 77 K as a function of simultaneously applied AC and DC magnetic fields from 0.01 to several hundred Oe. The separate contributions of the inter- and intragranular supercurrents are quite clearly resolved, enabling the development of a generalized critical state model, which with two components is found to well explain the AC permeability and harmonic generation power as functions of AC and DC fields up to the n = 9 harmonic. Intergranular currents dominate the behavior for fields less than about 50 Oe; intragranular currents dominate for fields greater than 100 Oe. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 19 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 1 PY 1992 VL 194 IS 1-2 BP 37 EP 46 DI 10.1016/0921-4534(92)90667-2 PG 10 WC Physics, Applied SC Physics GA HV263 UT WOS:A1992HV26300005 ER PT J AU LAM, QH JEFFRIES, CD AF LAM, QH JEFFRIES, CD TI TEMPERATURE-DEPENDENCE OF THE INTER-GRANULAR AND INTRAGRANULAR COMPONENTS OF THE COMPLEX PERMEABILITY IN A SINTERED YBA2CU3O7-DELTA CYLINDER - 2 TRANSITION-TEMPERATURES SO PHYSICA C LA English DT Article ID BA-CU-O; HIGH-TC SUPERCONDUCTORS; VORTEX-GLASS SUPERCONDUCTIVITY; AC SUSCEPTIBILITY; PHASE; CRYSTAL; LATTICE; MODELS AB For a cylindrical rod of sintered polycrystalline YBa2Cu3O7-delta, measurements are reported for the complex AC permeability mu'-i-mu" at H(DC) = 0 as a function of the amplitude H, of an applied AC field and for temperatures in the range 77.3 < T < 92 K. Two peaks mu" (H1) are observed, corresponding to the penetration fields H(g)*(T) and H(J)*(T) for the intra- and intergranular components of the sample, respectively. These penetration fields, and the critical current densities J(c,g)(T) and J(c,J)(T) derived from them by a generalized critical state model, extrapolate to zero at the temperatures T(cg) = 91.2 K and T(cJ) = 86.6 K. The upper critical temperature is that of the intrinsic grain material. The lower temperature is interpreted as that below which the grain order parameter phase becomes coherent throughout the sample. The value of (T(cg) - T(cJ)) can be understood from models (Shih, Ebner and Stroud; Clem) of a random 3D matrix of grains pressed into contact through Josephson weak links. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 35 TC 12 Z9 12 U1 2 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 MAY 1 PY 1992 VL 194 IS 1-2 BP 47 EP 54 DI 10.1016/0921-4534(92)90668-3 PG 8 WC Physics, Applied SC Physics GA HV263 UT WOS:A1992HV26300006 ER PT J AU NORMAN, MR AF NORMAN, MR TI WHAT IS THE SUPERCONDUCTING ORDER PARAMETER FOR UPT3 SO PHYSICA C LA English DT Article ID FERMION SYSTEM UPT3; MAGNETIC-FIELD; PHASE-DIAGRAM; UNCONVENTIONAL SUPERCONDUCTOR; TEMPERATURE-DEPENDENCE; DOUBLE TRANSITION; BROKEN SYMMETRY; ANISOTROPY; MODEL AB The author observed that information inferred from current interpretations of experimental data for the heavy electron superconductor UPt3 constrain the order parameter to be of E2u symmetry. Possible objections to the current interpretations will be given. RP NORMAN, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Norman, Michael/C-3644-2013 NR 28 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 1 PY 1992 VL 194 IS 1-2 BP 203 EP 204 DI 10.1016/0921-4534(92)90692-6 PG 2 WC Physics, Applied SC Physics GA HV263 UT WOS:A1992HV26300030 ER PT J AU WARNOCK, RL RUTH, RD AF WARNOCK, RL RUTH, RD TI LONG-TERM BOUNDS ON NONLINEAR HAMILTONIAN MOTION SO PHYSICA D LA English DT Article ID SYSTEMS; STABILITY; INTEGRATION AB In various important applications of Hamiltonian mechanics, notably in problems of accelerator design, it would be useful to set bounds on nonlinear motion for finite but very long times. Such bounds can be sought through construction of a canonical transformation to new action-angle variables (J, PSI), such that J is nearly constant, and PSI-advances almost linearly with the time. By examining the residual change in J during a time T0 from various initial conditions in the open domain-OMEGA of phase space, one can estimate the change in J during a much larger time T, on any orbit starting in a smaller open domain OMEGA-0 subset-of OMEGA. A numerical realization of this idea is described. The canonical transformations, equivalent to close approximations to invariant tori, are constructed by a new method in which surfaces are fitted to computed orbits. The perturbed tunes-nu (winding numbers) are determined as functions of J, and the inverse function J(nu is also computed. This leads to an accurate map of resonant tune lines into J space, which serves to locate dangerous regions of phase space. Near a single strong resonance, J varies more than usual but follows the pattern expected from the isolated resonance model. All calculations proceed from a time evolution map defined by a symplectic integrator or equivalent explicit formula. As an example, an accelerator problem in 2 1/2 degrees of freedom is treated. For betatron motion in a model accelerator with strong sextupole magnets, stability for 10(8) turns is predicted in a region of substantial nonlinearity. RP WARNOCK, RL (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 66 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD MAY PY 1992 VL 56 IS 2-3 BP 188 EP 215 DI 10.1016/0167-2789(92)90024-H PG 28 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA HX666 UT WOS:A1992HX66600006 ER PT J AU HOLM, DD KOVACIC, G AF HOLM, DD KOVACIC, G TI HOMOCLINIC CHAOS IN A LASER MATTER SYSTEM SO PHYSICA D LA English DT Article ID HAMILTONIAN-SYSTEMS; POWER SPECTRA; OPTICS; ORBITS AB In the slowly varying envelope approximation and the rotating wave approximation for the Maxwell-Schrodinger equations, we show that the presence of a small-amplitude probe laser in an excited, two-level, resonant medium leads to homoclinic chaos in the laser-matter dynamics. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP HOLM, DD (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,MS B284,LOS ALAMOS,NM 87545, USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 41 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD MAY PY 1992 VL 56 IS 2-3 BP 270 EP 300 DI 10.1016/0167-2789(92)90029-M PG 31 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA HX666 UT WOS:A1992HX66600011 ER PT J AU WELLS, JC OBERACKER, VE UMAR, AS BOTTCHER, C STRAYER, MR WU, JS PLUNIEN, G AF WELLS, JC OBERACKER, VE UMAR, AS BOTTCHER, C STRAYER, MR WU, JS PLUNIEN, G TI NONPERTURBATIVE ELECTROMAGNETIC LEPTON-PAIR PRODUCTION IN PERIPHERAL RELATIVISTIC HEAVY-ION COLLISIONS SO PHYSICAL REVIEW A LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; LATTICE FERMIONS; DILEPTON EMISSION; TIME AB We discuss a nonperturbative treatment of lepton-pair production caused by the strong and sharply pulsed electromagnetic fields generated in peripheral relativistic heavy-ion collisions with an emphasis on the capture process into the atomic K shell. We calculate, in a field-theoretical framework, impact-parameter-dependent probabilities and cross sections for such processes by solving the time-dependent Dirac equation on a three-dimensional Cartesian lattice using the basis-spline collocation method. We give a full discussion of the stationary states used in computing S-matrix elements. Use of the axial gauge for the electromagnetic potentials produces an interaction easier to implement on the lattice than the Lorentz gauge. Preliminary calculations are given for muon-pair production with capture into the K shell in collisions of Au-197 + Au-197 collider energies per nucleon of 2 and 100 GeV. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. RP WELLS, JC (reprint author), OAK RIDGE NATL LAB,CTR COMPUTAT INTENS PHYS,OAK RIDGE,TN 37831, USA. RI Umar, Ahmet/J-4125-2013; Wells, Jack/D-3675-2016 OI Umar, Ahmet/0000-0002-9267-5253; Wells, Jack/0000-0002-5083-3030 NR 51 TC 49 Z9 49 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6296 EP 6312 DI 10.1103/PhysRevA.45.6296 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300022 ER PT J AU SUN, WG MCCURDY, CW LENGSFIELD, BH AF SUN, WG MCCURDY, CW LENGSFIELD, BH TI THEORETICAL-STUDIES OF LOW-ENERGY ELECTRON-SILANE SCATTERING WITH AN ABINITIO DESCRIPTION OF TARGET RESPONSE SO PHYSICAL REVIEW A LA English DT Article ID CROSS-SECTIONS; POLYATOMIC-MOLECULES; COLLISIONS; METHANE; SIH4 AB Theoretical studies of low-energy electron-silane scattering are reported in which target polarization is included by using an ab initio optical potential. These calculations employ the complex Kohn scattering method and were undertaken both at the static-exchange level and with target polarization. A polarized virtual-orbital method, which was introduced in our earlier study of electron-methane scattering, was also employed in this study to generate a compact description of the closed channels included in the optical potential. Differential, integral, and momentum-transfer cross sections are reported at incident energies ranging from 0.2 to 20 eV. The computed total cross section shows a Ramsauer-Townsend minimum at 0.3 eV and a broad d-wave shape resonance at 3.0 eV. Excellent agreement is found between our polarized Kohn results and the recent experimental results of Wan, Moore, and Tossell [J. Chem. Phys. 91, 7340 (1989)]. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,THEORET ATOM & MOLEC PHYS GRP,LIVERMORE,CA 94550. RP SUN, WG (reprint author), OHIO STATE UNIV,DEPT CHEM,COLUMBUS,OH 43210, USA. NR 25 TC 22 Z9 22 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6323 EP 6331 DI 10.1103/PhysRevA.45.6323 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300025 ER PT J AU KRAVIS, SD CHURCH, DA JOHNSON, BM MERON, M JONES, KW LEVIN, JC SELLIN, IA AZUMA, Y BERRAHMANSOUR, N BERRY, HG DRUETTA, M AF KRAVIS, SD CHURCH, DA JOHNSON, BM MERON, M JONES, KW LEVIN, JC SELLIN, IA AZUMA, Y BERRAHMANSOUR, N BERRY, HG DRUETTA, M TI ELECTRON-TRANSFER FROM H-2 AND AR TO STORED MULTIPLY CHARGED ARGON IONS PRODUCED BY SYNCHROTRON RADIATION SO PHYSICAL REVIEW A LA English DT Article ID LOW ENERGIES; COLLISIONS; CAPTURE AB The rate coefficients for electron transfer from Ar and H-2 to Ar(q+) ions (3 less-than-or-equal-to q less-than-or-equal-to 6) have been measured using an ion-storage technique in a Penning ion trap. The ions were produced in the trap by K-shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar4+. The stored ion gas had an initial temperature near 480 K. The basic data determining the rate coefficients k(Ar(q+)) are the storage time constants of each charge state in the trap, in the presence of a measured pressure of target gas. The results of the measurements (in units of 10(-9) cm3 s-1) are k(Ar3+, H-2) = 4.3(0.7), k(Ar3+, Ar) = 1.6(0.2), k(Ar4+, H-2) = 5.2(0.6), k(Ar4+, Ar) = 2.5(0.3), k(Ar5+, H-2) = 5.9(0.7), k(Ar5+, Ar) = 2.9(0.3), k(Ar6+, H-2) = 8.5(l.2), and k(Ar6+, Ar) = 2.5(0.3). C1 TEXAS A&M UNIV SYST,DEPT PHYS,COLLEGE STN,TX 77843. BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. UNIV ST ETIENNE,TRAITEMENT SIGNAL & INSTRUMENT LAB,F-42100 ST ETIENNE,FRANCE. NR 24 TC 11 Z9 11 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6379 EP 6387 DI 10.1103/PhysRevA.45.6379 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300030 ER PT J AU GAO, RS DUTTA, CM LANE, NF SMITH, KA STEBBINGS, RF KIMURA, M AF GAO, RS DUTTA, CM LANE, NF SMITH, KA STEBBINGS, RF KIMURA, M TI EXPERIMENTAL AND THEORETICAL-STUDIES OF THE HE-2+-HE SYSTEM - DIFFERENTIAL CROSS-SECTIONS FOR DIRECT, SINGLE-CHARGE-TRANSFER, AND DOUBLE-CHARGE-TRANSFER SCATTERING AT KEV ENERGIES SO PHYSICAL REVIEW A LA English DT Article ID COLLISIONS; ABSOLUTE; HE; ELECTRON AB Measurements and calculations of differential cross sections for direct scattering, single charge transfer, and double charge transfer in collisions of 1.5-, 2.0-, 6.0-, and 10.0-keV He-3(2+) with a He-4 target are reported. The measurements cover laboratory scattering angles below 1.5-degrees with an angular resolution of about 0.03-degrees. A quantum-mechanical molecular-state representation is employed in the calculations; in the case of single charge transfer a two-state close-coupling calculation is carried out taking into account electron-translation effects. The theoretical calculations agree well with the experimental results for direct scattering and double charge transfer. For single charge transfer, the agreement is less satisfactory because of the limited number of molecular states incorporated in our calculations. The present calculation identifies the origins of oscillatory structures observed in the differential cross sections. C1 RICE UNIV,DEPT SPACE PHYS & ASTRON,HOUSTON,TX 77251. RICE UNIV,RICE QUANTUM INST,HOUSTON,TX 77251. ARGONNE NATL LAB,ARGONNE,IL 60439. RP GAO, RS (reprint author), RICE UNIV,DEPT PHYS,POB 1892,HOUSTON,TX 77251, USA. RI Gao, Ru-Shan/H-7455-2013 NR 16 TC 12 Z9 12 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6388 EP 6394 DI 10.1103/PhysRevA.45.6388 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300031 ER PT J AU SUSZCYNSKY, DM BOROVSKY, JE AF SUSZCYNSKY, DM BOROVSKY, JE TI MODIFIED STERNGLASS THEORY FOR THE EMISSION OF SECONDARY ELECTRONS BY FAST-ELECTRON IMPACT SO PHYSICAL REVIEW A LA English DT Article ID 10-100 KEV ELECTRONS; BACKSCATTERING; TARGETS; SOLIDS; FILMS AB The Sternglass theory [Sternglass, Phys. Rev. 108, 1 (1957)] for fast-ion-induced secondary-electron emission from metals has been modified to predict the secondary-electron yield from metals impacted by energetic (several keV to about 200 keV) electrons. The primary modification of the theory accounts for the contribution of the backscattered electrons to the production of secondary electrons based on a knowledge of the backscattered-electron energy distribution. The modified theory is in reasonable agreement with recent experimental data from gold targets in the 6-30-keV electron energy range. RP SUSZCYNSKY, DM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SPACE PLASMA PHYS GRP,LOS ALAMOS,NM 87545, USA. NR 30 TC 9 Z9 9 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6424 EP 6428 DI 10.1103/PhysRevA.45.6424 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300036 ER PT J AU COLLINS, LA MERTS, AL AF COLLINS, LA MERTS, AL TI MULTIPHOTON DETACHMENT OF NEGATIVE-IONS IN AN INTENSE RADIATION-FIELD SO PHYSICAL REVIEW A LA English DT Article ID 3-DIMENSIONAL SCHRODINGER-EQUATION; ELECTRIC-FIELDS; LASER FIELDS; H ION; ATOMS; ABSORPTION; IONIZATION; HALOGENS AB We have applied a momentum-space method to the solution of the three-dimensional time-dependent Schrodinger equation for electron detachment from a model negative ion, in particular H-. We have studied such phenomena as excess-photon detachment and threshold effects. For selected cases, we obtain excellent agreement with the Floquet calculations. We also present results in regimes of strong interest to experimental efforts. RP COLLINS, LA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP T-4,LOS ALAMOS,NM 87545, USA. NR 37 TC 19 Z9 19 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6615 EP 6621 DI 10.1103/PhysRevA.45.6615 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300055 ER PT J AU GARRETT, WR MOORE, MA HART, RC PAYNE, MG WUNDERLICH, R AF GARRETT, WR MOORE, MA HART, RC PAYNE, MG WUNDERLICH, R TI SUPPRESSION EFFECTS IN STIMULATED HYPER-RAMAN EMISSIONS AND PARAMETRIC 4-WAVE-MIXING IN SODIUM VAPOR SO PHYSICAL REVIEW A LA English DT Article ID MULTI-PHOTON IONIZATION; ENHANCED MULTIPHOTON IONIZATION; AMPLIFIED SPONTANEOUS EMISSION; UNFOCUSED LASER-BEAMS; 3RD-HARMONIC GENERATION; 3-PHOTON RESONANCE; HARMONIC-GENERATION; INTERFERENCE; COMPETITION; EXCITATION AB Experimental investigations of two-photon enhanced stimulated hyper-Raman and parametric four-wave-mixing emissions are described for tuning unfocused laser beams near two-photon resonance with 3D and 4D states in sodium vapor. Over wide ranges of vapor pressures, path lengths, and laser power densities, the gains for stimulated hyper-Raman (SHR) scattering and for parametric four-wave mixing (PFWM) can become very greatly reduced from values expected from simple considerations. The suppression of gain can arise from interferences produced at two-photon and three-photon resonances, and from ac Stark shifts produced by internally generated near-resonant fields. Quantitative comparisons are made between observed and theoretically predicted values for SHR and PFWM production. Of 12 predicted consequences of the interferences and Stark shifting on the nonlinear behavior, ten are demonstrated through the experiments. C1 UNIV TENNESSEE, DEPT PHYS, KNOXVILLE, TN 37996 USA. CALTECH, DIV GEOL & PLANETARY SCI, PASADENA, CA 91125 USA. RP GARRETT, WR (reprint author), OAK RIDGE NATL LAB, CHEM PHYS SECT, OAK RIDGE, TN 37831 USA. NR 50 TC 45 Z9 45 U1 1 U2 9 PU AMER 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 MAY 1 PY 1992 VL 45 IS 9 BP 6687 EP 6709 DI 10.1103/PhysRevA.45.6687 PG 23 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300064 ER PT J AU EDER, DC AMENDT, P WILKS, SC AF EDER, DC AMENDT, P WILKS, SC TI OPTICAL-FIELD-IONIZED PLASMA X-RAY LASERS SO PHYSICAL REVIEW A LA English DT Article ID IONIZATION AB A tabletop x-ray laser scheme involving lasing to the ground state of an ion following optical-field-induced ionization by a high-intensity short-pulse laser is studied, The role of the ground state in reducing the saturation intensity is calculated to be larger for H-like ions as compared with the effect in Li-like ions. Energy efficiencies of order 10(-5) are calculated for the 3d5/2-2p3/2 transition at 98 angstrom in Li-like Ne. The efficiency calculations are based on a driving laser with an intensity of 3 X 10(17) W/cm2, a wavelength of 0.25-mu-m, a pulse duration of 100 fsec, and an input energy of 25-100 mJ. A correction to the standard stimulated Raman scattering growth rate is given for a finite laser pulse. Use of short pulses is shown to be sufficient to control heating from stimulated Raman scattering in Li-like Ne. Extending the scheme to shorter wavelengths (e.g., Li-like Al at 52 angstrom) is difficult because of reduced efficiencies and excessive electron heating from Raman scattering. RP EDER, DC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 102 Z9 102 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6761 EP 6772 DI 10.1103/PhysRevA.45.6761 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300073 ER PT J AU ZHOU, B KISSEL, L PRATT, RH AF ZHOU, B KISSEL, L PRATT, RH TI MANY-ELECTRON CORRELATION-EFFECTS ON ANOMALOUS SCATTERING FACTORS SO PHYSICAL REVIEW A LA English DT Note ID PHOTOIONIZATION CROSS-SECTION; ARGON AB The effect of many-electron correlations on anomalous scattering factors in Rayleigh scattering is studied, in the case of the Ar atom, using dispersion relations and the relativistic random-phase approximation (RRPA). The correlation effect changes the Ar 3s-subshell photoionization cross sections significantly compared with the corresponding independent-particle approximation calculations; thereby the anomalous scattering factors of Rayleigh scattering from this subshell also experience marked structural changes. But the Ar 3p subshells dominate the coherent total-atom scattering amplitude so that subshell structural changes in the Ar 3s subshell due to many-electron correlation effects are not seen in the total-atom scattering cross section or the total-atom anomalous scattering factors, which are the physical observables in Rayleigh-scattering experiments. One anticipates this outcome generally for closed-shell atoms, while in the case of open shells one can anticipate a greater importance for the many-electron-correlation effects. C1 UNIV PITTSBURGH,DEPT PHYS & ASTRON,PITTSBURGH,PA 15260. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,COMP PHYS GRP,LIVERMORE,CA 94550. NR 20 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6906 EP 6909 DI 10.1103/PhysRevA.45.6906 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300092 ER PT J AU MAITI, A FALICOV, LM AF MAITI, A FALICOV, LM TI PHASE-DIAGRAM FOR SODIUM CLUSTERS SO PHYSICAL REVIEW A LA English DT Note ID ELECTRONIC SHELL STRUCTURE; METAL-CLUSTERS; MOLECULAR-DYNAMICS AB A temperature-size (T-N) phase diagram is derived for Na clusters of up to N approximately 1000 atoms. It is based on first-order pseudopotential calculations and the Lindemann criterion for melting. It contains three regions of stability: (1) a liquid (jellium) phase at temperatures above the melting line T(M)(N); (2) a phase related to the body-centered-cubic structure at temperatures below the melting line; and (3) a close-packed structure at very low temperatures and sufficiently large N. The melting line drops to T(M)(N) = 0 for N < 65. The phase diagram reduces a symptotically to the known phases of Na as N --> infinity, including the known martensitic transformation at T almost-equal-to 5 K. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP MAITI, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 27 TC 9 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY 1 PY 1992 VL 45 IS 9 BP 6918 EP 6921 DI 10.1103/PhysRevA.45.6918 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HT733 UT WOS:A1992HT73300095 ER PT J AU GARCIA, A COHEN, ML EGGERT, JH MOSHARY, F EVANS, WJ GOETTEL, KA SILVERA, IF AF GARCIA, A COHEN, ML EGGERT, JH MOSHARY, F EVANS, WJ GOETTEL, KA SILVERA, IF TI DIELECTRIC-PROPERTIES OF SOLID MOLECULAR-HYDROGEN AT HIGH-PRESSURE SO PHYSICAL REVIEW B LA English DT Article ID METALLIC HYDROGEN; PHASE-TRANSITION; EQUATION; STATE; TEMPERATURE; DEUTERIUM; H-2 AB We present experimental data on the dielectric behavior of solid molecular hydrogen to pressures up to 220 GPa. To complement these measurements, a calculation of the interband dielectric response was done for two prototype structures of hcp molecular solid hydrogen. It is shown that this theoretical approach allows a more complete analysis of the experimental data on compressed solid molecular hydrogen than previously possible. C1 HARVARD UNIV,LYMAN LAB PHYS,CAMBRIDGE,MA 02138. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP GARCIA, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Garcia, Alberto/A-7460-2008 OI Garcia, Alberto/0000-0001-5138-9579 NR 35 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 9709 EP 9715 DI 10.1103/PhysRevB.45.9709 PG 7 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300021 ER PT J AU COFFEY, MW CLEM, JR AF COFFEY, MW CLEM, JR TI THEORY OF RF MAGNETIC-PERMEABILITY OF ISOTROPIC TYPE-II SUPERCONDUCTORS IN A PARALLEL FIELD SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; VORTEX-GLASS SUPERCONDUCTIVITY; HIGH-TC SUPERCONDUCTORS; YBA2CU3O7-X; DEPENDENCE; MOTION; FORCES; CREEP AB A theoretical description of the complex rf magnetic permeability mu approximately = mu' + i-mu" of isotropic type-II superconductors in a parallel applied static magnetic field is presented. The results are based upon a self-consistent treatment of vortex dynamics which simultaneously includes the effects of pinning, flux flow, and flux creep, together with nonlocal vortex interactions. The results are expected to be valid over a wide range of frequencies, magnetic inductions, and temperatures. We show how a mu"-peak line, closely related to the irreversibility line, arises from the theoretical result for the permeability as a function of temperature, magnetic field, and frequency. This theory opens the possibility of investigating flux creep and depinning at frequencies into the GHz range. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP COFFEY, MW (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 45 TC 147 Z9 147 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 9872 EP 9881 DI 10.1103/PhysRevB.45.9872 PG 10 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300042 ER PT J AU HYBERTSEN, MS STECHEL, EB FOULKES, WMC SCHLUTER, M AF HYBERTSEN, MS STECHEL, EB FOULKES, WMC SCHLUTER, M TI MODEL FOR LOW-ENERGY ELECTRONIC STATES PROBED BY X-RAY ABSORPTION IN HIGH-TC CUPRATES SO PHYSICAL REVIEW B LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; SUPERCONDUCTING CU OXIDES; VALENCE-BOND STATE; OPTICAL-EXCITATIONS; HOLE CONCENTRATION; HUBBARD-MODEL; BAND; DENSITY; LA2-XSRXCUO4; PARAMETERS AB The low-energy electronic states in La2-xSrxCuO4 have recently been probed by soft-x-ray-absorption measurements as a function of doping (x) from the insulating well into the metallic (superconducting) regime. A model for understanding and interpreting those spectra is presented. The electronic structure of the active Cu-O planes is represented by an extended three-band Hubbard model whose parameters have been previously derived from quantum-chemical calculations. The essential additional Coulomb interaction between the core hole created in the absorption process and the nearby valence electrons has been included by calculating the necessary on-site and nearest-neighbor core-valence Coulomb parameters. The absorption spectra are calculated using exact-diagonalization techniques for finite clusters. The low-energy electronic structure can be represented within an effective one-band Hubbard model whose parameters are obtained by a mapping from the three-band model. The transition operator for the absorption process as well as the core-hole Coulomb potential are also mapped into the one-band model. The final calculations in the one-band model are performed for the insulator (half filling) and for several excess hole concentrations in the metal. The theoretical and experimental spectra are compared in detail. The calculations accurately account for the observed peak intensities as a function of doping. Important features include the gap between the preedge peaks in the metal, core-hole excitonic effects, and transfer of oscillator strength. In particular, the preedge peak separation is the charge-transfer gap (from the insulator) reduced by the core-hole exciton binding energy. The transfer of oscillator strength between the observed peaks, which is a key signature of the correlated band situation, is analyzed in detail. A doped charge-transfer insulator model for the electronic structure of the cuprates explains the essential features of the x-ray-absorption data. C1 SANDIA NATL LABS, DIV CONDENSED MATTER THEORY 1151, ALBUQUERQUE, NM 87185 USA. RP HYBERTSEN, MS (reprint author), AT&T BELL LABS, 600 MT AVE, MURRAY HILL, NJ 07974 USA. RI Stechel, Ellen/B-1253-2012; OI Foulkes, Matthew/0000-0001-8359-1122; Hybertsen, Mark S/0000-0003-3596-9754 NR 82 TC 108 Z9 108 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10032 EP 10050 DI 10.1103/PhysRevB.45.10032 PG 19 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300057 ER PT J AU KROL, A LIN, CS SOO, YL MING, ZH KAO, YH WANG, JH QI, M SMITH, GC AF KROL, A LIN, CS SOO, YL MING, ZH KAO, YH WANG, JH QI, M SMITH, GC TI SOFT-X-RAY-ABSORPTION STUDIES OF TL2BA2CA2CU3O10-DELTA HIGH-TC SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID BA-CU-O; ELECTRONIC-STRUCTURE; SPECTRA; TRANSITION; PHOTOEMISSION; TL2BA2CACU2O8; PHOTOELECTRON; FLUORESCENCE; DIHALIDES; SYMMETRY AB X-ray absorption around the oxygen K and the Cu L(III) edge of Tl2Ba2Ca2Cu3O10-delta high-T(c) superconductors with different oxygen content delta, was measured. Near the O 1s edge, three distinct pre-edge peaks with maxima at 528.3, 529.4, and 530.6 eV, respectively, are are revealed. They are ascribed to core-level revealed. They are ascribed to core-level excitations of oxygen 1s electrons to empty states which have predominantly oxygen 2p character, located in CuO2, BaO, and TlO planes, respectively. A strong dependence of T(c) on oxygen hole concentration at O(1) and O(1)' sites in the CuO2 layer is found. Near the Cu 2p3/2 edge, two main peaks are observed. The peak at 931.2 eV is ascribed to a 2p3d10 final state. This implies a predominately Cu2+ ground state which has mainly 3d9 character. The peak at 933 eV is ascribed to a 2p3d10L final state. This peak shows an intensity increase with T(c), i.e., with ligand hole concentration, and is believed to arise from a formally Cu3+ ground state which has mainly 3d9L character. No evidence of a monovalent (Cu1+) 3d10 ground state was found. C1 SUNY BUFFALO,DEPT CHEM,BUFFALO,NY 14260. BROOKHAVEN NATL LAB,UPTON,NY 11973. SUNY BUFFALO,NEW YORK STATE INST SUPERCONDUCT,BUFFALO,NY 14260. RP KROL, A (reprint author), SUNY BUFFALO,DEPT PHYS,BUFFALO,NY 14260, USA. NR 39 TC 21 Z9 21 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10051 EP 10056 DI 10.1103/PhysRevB.45.10051 PG 6 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300058 ER PT J AU SODERHOLM, L LOONG, CK KERN, S AF SODERHOLM, L LOONG, CK KERN, S TI INELASTIC-NEUTRON-SCATTERING STUDY OF THE ER-3+ ENERGY-LEVELS IN ERBA2CU3O7 SO PHYSICAL REVIEW B LA English DT Article ID CRYSTALLINE ELECTRIC-FIELD; OXYGEN; SUPERCONDUCTIVITY; GDBA2CU3O7-DELTA; YBA2CU3O7-X; MOSSBAUER; OPERATOR; MODEL AB Magnetic excitation spectra of ErBa2Cu3O7 have been measured by use of inelastic neutron scattering. Optimal experimental conditions allow the resolution of the transitions between the Er3+ ground state and all seven excited states within the 4I15/2 Russell-Saunders ground multiplet. The data are analyzed in terms of an intermediate-coupling crystal-field model, calculated using spherical-tensor techniques. Calculated spectra based on the results of this analysis are consistent with all experimental spectra, including those obtained at higher temperatures. The eigenfunctions and eigenvalues obtained from this analysis are used to calculate the magnetic properties expected of Er3+ in this crystal environment. RP SODERHOLM, L (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 37 TC 31 Z9 31 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10062 EP 10070 DI 10.1103/PhysRevB.45.10062 PG 9 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300060 ER PT J AU GRAY, KE KIM, DH VEAL, BW SEIDLER, GT ROSENBAUM, TF FARRELL, DE AF GRAY, KE KIM, DH VEAL, BW SEIDLER, GT ROSENBAUM, TF FARRELL, DE TI HIGH ANISOTROPY AND A DIMENSIONALITY CROSSOVER IN THE IRREVERSIBILITY BEHAVIOR OF OXYGEN-DEFICIENT YBA2CU3O7-Y SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTING STATES; CRITICAL FIELDS; FLUX; TEMPERATURE; CRYSTALS; LATTICE; TC AB The width in temperature of the reversible, lossy state of high-temperature superconductors (HTS's) in a magnetic field H depends on the degree of anisotropy. Compared to the parent compound YBa2Cu3O7, we show here that oxygen-deficient, YBa2Cu3O7-y single crystals, in which T(c) was varied from 10 to 55 K, are much more anisotropic and that the occurrence of the reversible, lossy state for the H parallel-to c axis is consistent with a crossover from three-dimensional (3D) vortex lines to 2D vortices, as recently proposed for the other highly anisotropic HTS's. These results, together with those from Tl2Ba2CaCu2Ox and Bi2Sr2CaCu2Ox, indicate universal behavior of almost isolated Cu-O bilayer units, albeit with different doping levels, and which display magnetic reversibility controlled by the residual weak interplanar coupling. C1 UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. CASE WESTERN RESERVE UNIV,DEPT PHYS,CLEVELAND,OH 44106. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. RP GRAY, KE (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Seidler, Gerald/I-6974-2012 NR 24 TC 46 Z9 46 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10071 EP 10074 DI 10.1103/PhysRevB.45.10071 PG 4 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300061 ER PT J AU ENGELBRECHT, JR RANDERIA, M ZHANG, L AF ENGELBRECHT, JR RANDERIA, M ZHANG, L TI LANDAU F FUNCTION FOR THE DILUTE FERMI GAS IN 2 DIMENSIONS SO PHYSICAL REVIEW B LA English DT Note ID BOSE CONDENSATION; HUBBARD-MODEL; STATE AB We study the Landau f function for a two-dimensional repulsive Fermi system in the dilute limit. We find the leading terms in the low-density expansion using second-order perturbation theory, following a method of Abrikosov and Khalatnikov. Further, using diagrammatic methods, we determine the essentially singular contribution coming from the two-hole bound state. The absence of a divergence in the f function, together with our earlier results on the quasiparticle lifetime, clearly demonstrates that the system is a Fermi liquid in the low-density regime. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. RP ENGELBRECHT, JR (reprint author), UNIV ILLINOIS,DEPT PHYS,1110 W GREEN ST,URBANA,IL 61801, USA. NR 14 TC 44 Z9 44 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10135 EP 10138 DI 10.1103/PhysRevB.45.10135 PG 4 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300076 ER PT J AU GRONBECHJENSEN, N BISHOP, AR FALO, F LOMDAHL, PS AF GRONBECHJENSEN, N BISHOP, AR FALO, F LOMDAHL, PS TI LANGEVIN-DYNAMICS SIMULATION OF RELAXATION IN LARGE FRUSTRATED JOSEPHSON-JUNCTION ARRAYS SO PHYSICAL REVIEW B LA English DT Note ID ISING SPIN-GLASS; IV CHARACTERISTICS; MODEL; BEHAVIOR AB Simulations of large two-dimensional arrays of Josephson junctions by a classical Langevin molecular-dynamics technique on the massively parallel Connection Machine 2 are reported. Long-time relaxation studies of initially random flux configurations are performed. Hierarchical scales in both time and space are revealed when the system is under the influence of thermal noise and/or spatial disorder, as well as a perpendicular magnetic field. C1 UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. UNIV CALIF LOS ALAMOS SCI LAB, ADV COMP LAB, LOS ALAMOS, NM 87545 USA. UNIV SARAGOSSA, CSIC, DEPT CIENCIA & TECNOL MAT & FLUIDOS, ZARAGOZA, SPAIN. RI Falo, Fernando/B-9137-2011 OI Falo, Fernando/0000-0002-9551-624X NR 26 TC 15 Z9 15 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 MAY 1 PY 1992 VL 45 IS 17 BP 10139 EP 10142 DI 10.1103/PhysRevB.45.10139 PG 4 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300077 ER PT J AU MACDONALD, AH AKERA, H NORMAN, MR AF MACDONALD, AH AKERA, H NORMAN, MR TI LANDAU QUANTIZATION AND PARTICLE-PARTICLE LADDER SUMS IN A MAGNETIC-FIELD SO PHYSICAL REVIEW B LA English DT Note ID FERMI-SURFACE; SUPERCONDUCTIVITY AB We evaluate the sum of particle-particle ladder diagrams for a two-dimensional (2D) electron gas in the presence of an external magnetic field. The evaluation depends on the observation that the quantized center-of-mass kinetic energy is conserved in electron-electron scattering events. For a delta-function interaction scattering channels with different center-of-mass kinetic energy separate and the integral equation reduces to an algebraic equation which can be solved explicitly. Divergences associated with superconducting instabilities are identified. In the weak-field limit a connection is established between the different scattering channels and different solutions of the linearized Ginzburg-Landau equations. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP MACDONALD, AH (reprint author), INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405, USA. RI Norman, Michael/C-3644-2013 NR 21 TC 35 Z9 35 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10147 EP 10150 DI 10.1103/PhysRevB.45.10147 PG 4 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300079 ER PT J AU SIGNORE, PJC KOSTER, JP KNETSCH, EA VANWOERKENS, CMCM MEISEL, MW BROWN, SE FISK, Z AF SIGNORE, PJC KOSTER, JP KNETSCH, EA VANWOERKENS, CMCM MEISEL, MW BROWN, SE FISK, Z TI INDUCTIVE RESPONSE OF ORIENTED UPT3 IN THE SUPERCONDUCTING STATE SO PHYSICAL REVIEW B LA English DT Note ID ANISOTROPIC SUPERCONDUCTORS; TEMPERATURE-DEPENDENCE; SPIN FLUCTUATIONS; PHASE-DIAGRAM; HEAT; FIELD; PENETRATION; DEPTH AB The inductive response of single crystals of UPt3 have been studied from 1 K to 70 mK using mutual inductance techniques to measure chi' and chi" at 31.7 and 317 Hz and tunnel diode resonant methods at 3 and 16 MHz, for the excitation fields parallel to the symmetry axis of the crystal. A double bump in the chi" measurements is clearly distinguishable and is consistent with the H = 0 phase diagrams of other workers. The temperature dependence of the magnetic penetration depth has been extracted from the measurements which indicate that the low-frequency results are linear for T/T(c) < 0.5, while the high-frequency data indicate a power-law dependence close to T2. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV FLORIDA,CTR ULTRA LOW TEMP RES,GAINESVILLE,FL 32611. RP SIGNORE, PJC (reprint author), UNIV FLORIDA,DEPT PHYS,GAINESVILLE,FL 32611, USA. NR 37 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10151 EP 10154 DI 10.1103/PhysRevB.45.10151 PG 4 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300080 ER PT J AU SEIDLER, GT ROSENBAUM, TF VEAL, BW AF SEIDLER, GT ROSENBAUM, TF VEAL, BW TI 2-DIMENSIONAL SUPERCONDUCTOR-INSULATOR TRANSITION IN BULK SINGLE-CRYSTAL YBA2CU3O6.38 SO PHYSICAL REVIEW B LA English DT Note ID PHASE-TRANSITIONS; DISORDER; FILMS; YBA2CU3O7-DELTA; ONSET AB We use a magnetic field to tune a highly anisotropic single crystal of oxygen-deficient YBa2Cu3O7-delta with a transition temperature of 2 K through the superconductor-insulator transition. The sheet resistance scales with temperature, 0.05 less-than-or-equal-to T less-than-or-equal-to 1.0 K, and field, 0 less-than-or-equal-to H less-than-or-equal-to 94 kOe, in a manner predicted by a theory for quantum phase transitions in disordered two-dimensional superconductors. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. RP SEIDLER, GT (reprint author), UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637, USA. RI Seidler, Gerald/I-6974-2012 NR 20 TC 60 Z9 60 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 17 BP 10162 EP 10164 DI 10.1103/PhysRevB.45.10162 PG 3 WC Physics, Condensed Matter SC Physics GA HR543 UT WOS:A1992HR54300083 ER PT J AU NIKZAD, S CALAWAY, WF YOUNG, CE PELLIN, MJ GRUEN, DM TOMBRELLO, TA HOUSLEY, RM AF NIKZAD, S CALAWAY, WF YOUNG, CE PELLIN, MJ GRUEN, DM TOMBRELLO, TA HOUSLEY, RM TI VELOCITY DISTRIBUTION AND YIELD MEASUREMENTS OF FE EJECTED FROM FES2 DURING ION-BOMBARDMENT SO PHYSICAL REVIEW B LA English DT Article ID LASER FLUORESCENCE; SURFACE; ATOMS; ALLOYS; SPECTROSCOPY; IMPACT; CR AB Secondary neutrals sputtered by 3-keV Ar+ from FeS2 and Fe were studied by use of laser postionization mass spectrometry and laser-induced fluorescence spectroscopy. The velocity distribution and yield of Fe from the FeS2 sample were measured. The velocity distribution of Fe sputtered from the sulfide is very similar to that of sputtered Fe from the pure metal with both distributions peaking at nearly the same velocity. The yield of Fe from the sulfide target, after prolonged bombardment, was at most 27% of the yield from the metal. The results are compared with Monte Carlo calculations using the TRIM (transport of ions in matter) code. The total sputtering yield of FeS2 was measured using profilometry and was compared with the same measurements of the sputtered metal targets. The surface of the FeS2 was examined by x-ray photoelectron spectroscopy before and after ion bombardment and indicates preferential sputtering of S at low primary ion doses. After prolonged bombardment, the surface becomes similar to that of FeS. The profilometry measurements and the yield measured by mass spectrometry indicate that some of the sputtered Fe is not observed in the neutral ground state; we propose that the unobserved Fe is in the form of clusters. C1 CALTECH,DEPT PHYS,PASADENA,CA 91125. CALTECH,DIV PHYS MATH & ASTRON,PASADENA,CA 91125. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ROCKWELL INT CORP,CTR SCI,THOUSAND OAKS,CA 91360. RP NIKZAD, S (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 41 TC 6 Z9 6 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10255 EP 10263 DI 10.1103/PhysRevB.45.10255 PG 9 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600007 ER PT J AU GOLDMAN, AI STASSIS, C DEBOISSIEU, M CURRAT, R JANOT, C BELLISSENT, R MOUDDEN, H GAYLE, FW AF GOLDMAN, AI STASSIS, C DEBOISSIEU, M CURRAT, R JANOT, C BELLISSENT, R MOUDDEN, H GAYLE, FW TI PHONONS IN ICOSAHEDRAL AND CUBIC AL-LI-CU SO PHYSICAL REVIEW B LA English DT Article ID ONE-DIMENSIONAL QUASICRYSTALS; INELASTIC NEUTRON-SCATTERING; QUASI-CRYSTALS; INCOMMENSURATE CRYSTALS; MOMENTS METHOD; SPECIAL POINTS; DIFFRACTION; MODES; MN; QUASILATTICES AB We describe the results of inelastic-neutron-scattering measurements on single grains of icosahedral Al-Li-Cu and the related cubic R phase. Measurements along the high-symmetry twofold, threefold, and fivefold axes of the icosahedral phase clearly show the existence of well-defined propagating modes, with isotropic dispersion, near strong Bragg peaks. The spectral weight of the acoustic phonons scale linearly with the integrated intensity of the associated zone centers. In several cases we are able to identify "quasi"-Brillouin-zones, with stationary points at the "special" high-symmetry points of a simple icosahedral lattice. While the phonon dispersion for transverse and longitudinal acoustic modes along the twofold axis of the cubic R phase is quite similar to that found for the icosahedral phase, differences are found in the higher-energy modes; the behavior of the higher-energy modes of the icosahedral phase is consistent with an enhanced degree of spatial localization for these excitations. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. CENS,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. NATL INST STAND & TECHNOL,DIV MET,GAITHERSBURG,MD 20899. RP GOLDMAN, AI (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 56 TC 44 Z9 44 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10280 EP 10291 DI 10.1103/PhysRevB.45.10280 PG 12 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600010 ER PT J AU LU, ZW WEI, SH ZUNGER, A AF LU, ZW WEI, SH ZUNGER, A TI ELECTRONIC-STRUCTURE OF ORDERED AND DISORDERED CU3AU AND CU3PD SO PHYSICAL REVIEW B LA English DT Article ID SPECIAL-QUASIRANDOM-STRUCTURES; ABSORPTION FINE-STRUCTURE; CORE-LEVEL SHIFTS; PARTIAL DENSITIES; RANDOM ALLOYS; LATTICE RELAXATIONS; BAND-STRUCTURE; METAL-ALLOYS; STATES; CU AB In ordered L1(2)-type A3B compounds, each A atom is coordinated by 8A + 4B atoms, while each B atom is coordinated by 12A atoms. By symmetry, all A-A, A-B, and B-B bond lengths are equal. When this structure disorders to form the substitutionally random A0.75 B0.25 alloy, each atom acquires a distribution of different types of coordination shells. Concomitantly with this reduction in site symmetries, (I) topologically different A atoms (and separately, different B atoms) can have unequal charges, and (II) the various bonds need not be of equal average lengths [R] (i.e.,[R(A-A)] not-equal [R(A-B)] not-equal [R(B-B)]). Furthermore, (III) there can be a distribution of bond length values around [R(ij)] for each of the three chemical bond types. In this work we study the effects of such charge fluctuations (I) and relaxational fluctuations [(II) and (III)] on the electronic structure of CU3Au and Cu3Pd. The random alloys are modeled by the special quasirandom structure (SQS), whereby the sites of a periodic supercell are occupied by A and B atoms so that the first few radial correlation functions closely reproduce the average correlation functions in an infinite substitutional random network. Instead of requiring that each atom "see" an identical, average medium, as is the case in the homogeneous site-coherent-potential approximation (SCPA), we thus create a distribution of distinct local environments whose average corresponds to the random alloy. Application of a first-principles local-density method (linearized augmented-plane-wave method) to the SQS then provides the energy-minimizing equilibrium relaxations, charge density, density of states, and formation enthalpy. We find that charge and relaxational fluctuations neglected in the SCPA lead to a significant stabilization of the alloy (approximately 30% lowering in mixing enthalpy) and to substantial (approximately 1 eV) nonrigid shifts in the electronic energy levels. RP NATL RENEWABLE ENERGY LAB, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 84 TC 84 Z9 84 U1 0 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10314 EP 10330 DI 10.1103/PhysRevB.45.10314 PG 17 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600014 ER PT J AU BAILLIE, CF GUPTA, R HAWICK, KA PAWLEY, GS AF BAILLIE, CF GUPTA, R HAWICK, KA PAWLEY, GS TI MONTE-CARLO RENORMALIZATION-GROUP STUDY OF THE 3-DIMENSIONAL ISING-MODEL SO PHYSICAL REVIEW B LA English DT Article ID REDUNDANT OPERATORS; SIMULATIONS; BEHAVIOR; D=3 AB We present results of a Monte Carlo renormalization-group study of the three-dimensional Ising model on 64(3) and 128(3) simple-cubic lattices. The eigenvalues of a linearized transformation matrix, constructed with the use of 53 even operators and 46 odd operators, are shown to be free of truncation errors. Our estimate of the critical coupling is 0.221 652 +/- 0.000 003 +/- 0.000 001 where the first error is statistical and the second due to the finite number of blocking steps. The results for the relevant exponents are nu = 0.624(2) and eta = 0.026(3). This estimate for nu lies 2-3-sigma below that obtained from other methods. The correction-to-scaling exponent is found to lie in the range omega = 0.8-0.85. We also find that the subleading magnetic exponent is relevant and present evidence that it corresponds to a redundant eigenvector of the majority-rule blocking transformation. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV EDINBURGH,DEPT PHYS,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. RP BAILLIE, CF (reprint author), UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309, USA. RI Hawick, Ken/E-1609-2013 OI Hawick, Ken/0000-0002-2447-3940 NR 40 TC 134 Z9 135 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10438 EP 10453 DI 10.1103/PhysRevB.45.10438 PG 16 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600027 ER PT J AU COFFEY, MW CLEM, JR AF COFFEY, MW CLEM, JR TI THEORY OF RF MAGNETIC-PERMEABILITY OF TYPE-II SUPERCONDUCTORS IN SLAB GEOMETRY WITH AN OBLIQUE APPLIED STATIC MAGNETIC-FIELD SO PHYSICAL REVIEW B LA English DT Article ID VORTEX-GLASS SUPERCONDUCTIVITY; BA-CU-O; FLUX CREEP; YBA2CU3O7-X; DEPENDENCE; CRYSTAL; FORCES AB A self-consistent theory of dynamic vortex response in the linear regime is extended to describe (a) the rf complex magnetic permeability-mu suitable for slab geometry and (b) the complicating effect of an oblique applied static magnetic field. The resulting theory, which is expected to be valid over a broad range of static-field magnitude and of frequency, for temperatures from absolute zero through the transition temperature, and for all angles of applied static field with respect to the superconductor surface and microwave field, includes in a unified manner vortex pinning, flux flow, and flux creep by using the complex dynamic vortex mobility. In particular, we show how mu depends upon the magnitude and direction of the internal magnetic induction B0 generated by a uniform array of vortices in the superconductor, and we give the corresponding numerical results. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP COFFEY, MW (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 48 TC 92 Z9 92 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10527 EP 10535 DI 10.1103/PhysRevB.45.10527 PG 9 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600037 ER PT J AU SCHMIEDESHOFF, GM FISK, Z SMITH, JL AF SCHMIEDESHOFF, GM FISK, Z SMITH, JL TI UPPER CRITICAL FIELDS OF THE HEAVY-FERMION SUPERCONDUCTOR UBE13 SO PHYSICAL REVIEW B LA English DT Article ID LOW-TEMPERATURE MAGNETORESISTIVITY; CRITICAL MAGNETIC-FIELD; DEMAGNETIZING FIELDS; PHASE-TRANSITION; UPT3; U1-XTHXBE13; DIAGRAM; MODEL; ORDER AB We report high-precision measurements of the upper critical magnetic field of UBe13 as determined from the behavior of magnetic forces and torques acting on our samples. Our results suggest the presence of two sharp features or "kinks" in the upper critical field as a function of temperature in both single-crystal and polycrystalline samples. We discuss these results in light of recent theoretical and experimental work on the coexistence of heavy-fermion superconductivity with magnetic and/or additional superconducting states. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP SCHMIEDESHOFF, GM (reprint author), BOWDOIN COLL,DEPT PHYS,BRUNSWICK,ME 04011, USA. NR 38 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10544 EP 10548 DI 10.1103/PhysRevB.45.10544 PG 5 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600039 ER PT J AU JIA, YX LIU, JZ LAN, MD KLAVINS, P SHELTON, RN RADOUSKY, HB AF JIA, YX LIU, JZ LAN, MD KLAVINS, P SHELTON, RN RADOUSKY, HB TI UPPER CRITICAL-FIELD HC2 OF SINGLE-CRYSTAL Y1-XPRXBA2CU3O7-DELTA SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; NORMAL-STATE PROPERTIES; MUON-SPIN RELAXATION; MAGNETIC-FIELD; CRITICAL FLUCTUATIONS; PR; YBA2CU3O7-DELTA; SUPPRESSION; PRBA2CU3O7; TRANSITION AB We report measurements of upper critical fields H(c2) of Y1-xPrxBa2CU3O7-delta single crystals, with x varying from 0 to 0.54. Values of H(c2) were determined resistively. For various Pr concentrations, we find that H(c2) shows a linear temperature dependence under a field up to 5 T both parallel and perpendicular to the c axis. The coherence length xi(ab)(0), xi(c)(0), and zero-temperature upper critical field H(c2)(0) for various Pr concentrations and field configurations are derived from these experimental results. A possible mechanism responsible for the observed composition dependence of the normalized upper-critical-field slope in the H parallel-to c case is discussed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP JIA, YX (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. NR 41 TC 41 Z9 42 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10609 EP 10615 DI 10.1103/PhysRevB.45.10609 PG 7 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600046 ER PT J AU GIAPINTZAKIS, J LEE, WC RICE, JP GINSBERG, DM ROBERTSON, IM WHEELER, R KIRK, MA RUAULT, MO AF GIAPINTZAKIS, J LEE, WC RICE, JP GINSBERG, DM ROBERTSON, IM WHEELER, R KIRK, MA RUAULT, MO TI PRODUCTION AND IDENTIFICATION OF FLUX-PINNING DEFECTS BY ELECTRON-IRRADIATION IN YBA2CU3O7-X SINGLE-CRYSTALS SO PHYSICAL REVIEW B LA English DT Article ID ENHANCEMENT AB An enhancement in J(c) of YBa2Cu3O7-x single crystals in a magnetic field is observed after irradiation with 1-MeV electrons. Typically, a factor-of-2 increase in J(c) is deduced from magnetic hysteresis loops at 10 K and 1 T with H parallel-to c. This enhancement is about 1/2 of that produced by proton and neutron irradiations under similar measurement conditions. In situ transmission-electron-microscopy studies found no visible defects induced by electron irradiation, which means that point defects or small clusters (of size < 2 nm) are responsible for the extra pinning. Annealing studies suggest that effective pinning centers for H parallel-to c do not include oxygen vacancies in the Cu-O chains. Based on calculations of cross sections for displacements on the different sublattices, and in conjunction with the results of a J(c) calculation by Kes, we suggest that the most likely pinning defect is the displacement of a Cu atom from the CuO2-plane sites. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. CTR SPECTROMETRIE NUCL & SPECTROMETRIE MASSE,F-91406 ORSAY,FRANCE. UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801. RP GIAPINTZAKIS, J (reprint author), UNIV ILLINOIS,DEPT PHYS,1110 W GREEN ST,URBANA,IL 61801, USA. NR 17 TC 72 Z9 72 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10677 EP 10683 DI 10.1103/PhysRevB.45.10677 PG 7 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600053 ER PT J AU SCHIRBER, JE OVERMYER, DL MOROSIN, B VENTURINI, EL BAUGHMAN, R EMIN, D KLESNAR, H ASELAGE, T AF SCHIRBER, JE OVERMYER, DL MOROSIN, B VENTURINI, EL BAUGHMAN, R EMIN, D KLESNAR, H ASELAGE, T TI PRESSURE-DEPENDENCE OF THE SUPERCONDUCTING TRANSITION-TEMPERATURE IN SINGLE-CRYSTAL NBBX (X NEAR 2) WITH T(C) = 9.4-K SO PHYSICAL REVIEW B LA English DT Note AB We have measured the pressure dependence of the superconducting transition temperature (9.4 K) of NbBx with x near 2 by direct comparison with elemental Nb. We find dT(c)/dP = 0.04 (+/- 0.015) K/kbar. RP SCHIRBER, JE (reprint author), SANDIA NATL LABS,DEPT PHYS,ALBUQUERQUE,NM 87185, USA. NR 8 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10787 EP 10788 DI 10.1103/PhysRevB.45.10787 PG 2 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600067 ER PT J AU KIM, DH GRAY, KE TROCHET, MD AF KIM, DH GRAY, KE TROCHET, MD TI SCALING BEHAVIOR OF FLUCTUATION CONDUCTIVITY OF HIGH-TEMPERATURE SUPERCONDUCTORS IN A MAGNETIC-FIELD SO PHYSICAL REVIEW B LA English DT Note ID RESISTIVE TRANSITION; CRITICAL CURRENTS; MAGNETORESISTANCE; RESISTANCE; FILMS; TAILS; TC AB Fluctuation conductivities of YBa2CU3Ox and T12Ba2CaCu2Ox films have been analyzed beyond the Gaussian approximation by using the two- (2D) and three-dimensional (3D) scaling functions in the critical region. Near the mean-field transition temperature T(c)(H), the fluctuation conductivity of YBa2CU3Ox shows a 3D scaling behavior similar to that seen in the single crystal, suggesting that fluctuations are coherent over the adjacent Cu-O layers in this region. The fluctuation conductivity of T12Ba2CaCU2Ox shows good agreement with 2D scaling behavior for temperatures higher than a few degrees above T(c)(H), but a deviation occurs very near and below T(c)(H). The poor scaling in that region may be caused by double transitions, which are systematically seen in the highly anisotropic high-T(c) superconductors like T12Ba2CaCU2Ox, preventing the determination of the validity of a 2D scaling formula near and below T, (H). RP KIM, DH (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 21 TC 42 Z9 42 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10801 EP 10804 DI 10.1103/PhysRevB.45.10801 PG 4 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600071 ER PT J AU WYSIN, GM BISHOP, AR AF WYSIN, GM BISHOP, AR TI DYNAMIC CORRELATIONS IN A CLASSICAL 2-DIMENSIONAL HEISENBERG-ANTIFERROMAGNET - REPLY SO PHYSICAL REVIEW B LA English DT Letter AB In a recent publication [Wysin and Bishop, Phys. Rev. B 42, 810 (1990)], we incorrectly derived the condition that the wave-vector- and time-dependent dynamic structure function S(q,t) for isotropic Heisenberg magnets should satisfy dS(q,t)/dt\t=0 = 0. In the preceding Comment by Brown, it has been pointed out that the derivation did not preserve the spin commutation relations. However, the above quantity is correctly determined by a sum of three-point spin correlations, [SnxSmySmz], which we show are all identically zero in any number of space dimensions. Therefore, the condition is valid, and indeed implies that a sum of Lorentzians cannot be used to fit the frequency-dependent dynamic correlation function S (q,omega). C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP WYSIN, GM (reprint author), KANSAS STATE UNIV AGR & APPL SCI,DEPT PHYS,MANHATTAN,KS 66506, USA. RI Wysin, Gary/I-8162-2012 OI Wysin, Gary/0000-0001-8422-800X NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1992 VL 45 IS 18 BP 10812 EP 10813 DI 10.1103/PhysRevB.45.10812 PG 2 WC Physics, Condensed Matter SC Physics GA HT386 UT WOS:A1992HT38600074 ER PT J AU PICKLESIMER, A RICE, RA BRANDENBURG, R AF PICKLESIMER, A RICE, RA BRANDENBURG, R TI DELTA DEGREES OF FREEDOM IN TRINUCLEI .3. THE ARGONNE DELTA MODEL SO PHYSICAL REVIEW C LA English DT Article ID ISOBAR AB The Argonne DELTA-model is used to study the effect of one-DELTA and DELTA-DELTA-degrees of freedom on the triton binding energy (E(T)). Exploratory calculations decompose the J less-than-or-equal-to 4 system of interest into restricted (JL2) calculations, with J less-than-or-equal-to 2 and L(N-DELTA), L(DELTA-DELTA) less-than-or-equal-to 2, and a 130 keV attractive correction. A JL2 dispersive calculation yields E(T) = 6.50 MeV, while a full JL2 calculation gives 7.16 MeV, revealing an attractive DELTA-three-body-force (3BF) contribution of 660 keV. Comparing to the nucleons-only value, E(T) = 7.58 MeV, the size of the repulsive-DELTA dispersive effect is 1080 keV. The one-DELTA and DELTA-DELTA-3BF contributions are found to be 440 and 220 keV, respectively, while the corresponding full J less-than-or-equal-to 4 values are 450 and 290 keV, respectively. The net J less-than-or-equal-to 4 result is E(T) = 7.29 MeV versus a nucleons-only value of 7.67 MeV: the attractive DELTA-3BF contribution is not quite sufficient to cancel the 1120 keV repulsive-DELTA dispersive effect. The cancellation between dispersive and 3BF effects is similar to that found for the Hannover DELTA-model, although the residual DELTA-repulsive effect found for the Argonne model is non-negligible: DELTA-effects are found not to resolve the triton binding energy defect. It is also evident from these results that DELTA-dispersive effects are not adequately represented in nucleons-only models simply by force of fitting the NN data. Thus, the present results confirm the qualitative implications of our previous studies using the Hannover DELTA-model, including the fact that DELTA-DELTA-effects are appreciable. C1 PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907. RP PICKLESIMER, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545, USA. NR 10 TC 32 Z9 32 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 MAY PY 1992 VL 45 IS 5 BP 2045 EP 2054 DI 10.1103/PhysRevC.45.2045 PG 10 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100002 ER PT J AU HAIDENBAUER, J HOLINDE, K JOHNSON, MB AF HAIDENBAUER, J HOLINDE, K JOHNSON, MB TI FOLDED-DIAGRAM NUCLEON-NUCLEON POTENTIAL FOR APPLICATION TO THE MANY-BODY PROBLEM SO PHYSICAL REVIEW C LA English DT Article ID MESON-EXCHANGE MODEL; DEUTERON ELASTIC-SCATTERING; HIGH MOMENTUM-TRANSFER; TRITON BINDING-ENERGY; MAGNETIC FORM-FACTOR; ASYMPTOTIC D-STATE; RETARDATION; RANGE; FREEDOM AB We calculate an energy-independent nucleon-nucleon potential using the folded-diagram expansion following closely the philosophy for selecting one- and two-meson-exchange terms that led to the successful Bonn energy-dependent interaction. Coupling parameters are very similar in the two cases, as is the reproduction of the scattering phase shifts and deuteron properties, including the electromagnetic form factors. We also present a simpler one-meson-exchange folded-diagram potential. We study the properties of the many-body system using the two energy-independent interactions. The triton is underbound by about 1 MeV, and nuclear matter underbinds at a saturation density considerably above the empirical density, suggesting the need for intrinsic three-body forces. These are considerably different from the properties attributed to the energy-dependent Bonn interactions, reflecting our earlier observation that numerous higher-order corrections need to be considered in the energy-dependent scheme to obtain comparable many-body results. C1 UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. RP HAIDENBAUER, J (reprint author), FORSCHUNGSZENTRUM JULICH, INST KERNPHYS, W-5170 JULICH 1, GERMANY. NR 51 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2055 EP 2067 DI 10.1103/PhysRevC.45.2055 PG 13 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100003 ER PT J AU FRANKLE, CM BOWMAN, CD BOWMAN, JD SEESTROM, SJ SHARAPOV, EI POPOV, YP ROBERSON, NR AF FRANKLE, CM BOWMAN, CD BOWMAN, JD SEESTROM, SJ SHARAPOV, EI POPOV, YP ROBERSON, NR TI NEUTRON RESONANCE SPECTROSCOPY ON CD-113 THE PARA-WAVE LEVELS SO PHYSICAL REVIEW C LA English DT Article AB Weak levels in the compound nucleus Cd-114 were located by neutron time-of-flight spectroscopy techniques. Neutron capture measurements were performed with both a natural cadmium target and a highly enriched Cd-113 target. A total of 22 new resonances were located in the neutron energy interval 20-500 eV and were assumed to be p wave. Resonance parameters, E0 and g-GAMMA(n), are given for the newly identified levels. The p-wave strength function was determined to be 10(4)S1 = 2.8 +/- 0.8 and the average level spacing = 14 eV. Comparison of the reduced widths with a Porter-Thomas distribution is consistent with having missed 15% of the p-wave levels. C1 DUBNA JOINT NUCL RES INST,DUBNA,USSR. DUKE UNIV,DURHAM,NC 27706. TRIANGLE UNIV NUCL LAB,DURHAM,NC 27706. RP FRANKLE, CM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 12 TC 6 Z9 6 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2143 EP 2146 DI 10.1103/PhysRevC.45.2143 PG 4 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100008 ER PT J AU WOLFS, FLH REHM, KE MA, WC SCHIFFER, JP WANG, TF AF WOLFS, FLH REHM, KE MA, WC SCHIFFER, JP WANG, TF TI ELASTIC-SCATTERING AND QUASI-ELASTIC TRANSFER IN THE SYSTEM SE-76, SE-82+PT-192, PT-198 SO PHYSICAL REVIEW C LA English DT Article ID TRANSFER CROSS-SECTIONS; NUCLEON-TRANSFER; NEUTRON TRANSFER AB Elastic scattering and quasielastic transfer yields have been measured for Se-76, Se-82 + Pt-192, Pt-198 using Se-76 and Se-82 'beams with laboratory energies of 487.7 and 499.0 MeV, respectively. The variation of the one-neutron transfer yields as function of projectile and target mass can be understood on the basis of Q matching. Quasielastic transfer contributes at most 30% to the total reaction cross section with the remainder probably accounted for by deep-inelastic scattering. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP WOLFS, FLH (reprint author), UNIV ROCHESTER,NUCL STRUCT RES LAB,ROCHESTER,NY 14627, USA. NR 20 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2283 EP 2289 DI 10.1103/PhysRevC.45.2283 PG 7 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100024 ER PT J AU BROOKS, ML BASSALLECK, B DIETERLE, BD REEDER, RA LEE, DM MCGILL, JA SCHILLACI, ME RISTINEN, RA SMYTHE, WR AF BROOKS, ML BASSALLECK, B DIETERLE, BD REEDER, RA LEE, DM MCGILL, JA SCHILLACI, ME RISTINEN, RA SMYTHE, WR TI NEUTRON-INDUCED PION-PRODUCTION ON C, AL, CU, AND W AT 200-600 MEV SO PHYSICAL REVIEW C LA English DT Article ID INTRANUCLEAR-CASCADE CALCULATION; CROSS-SECTIONS; CHARGED PIONS; PROTONS; NUCLEI; SPECTRA AB Inclusive double differential neutron induced pi+ and pi- production cross sections were measured as a function of neutron energy for four targets: C, Al, Cu, and W. The neutron energy range was 200-600 MeV and the pion angular range was 25-degrees-125-degrees (laboratory). The charge, scattering angle, and energy of the pions were measured. The measurements are compared with intranuclear cascade (INC) calculations and a previous experiment that measured the sum of the pi+ and pi--cross sections. Our data agree with the measured data, but the INC calculations give only moderate agreement both with the double differential cross sections as well as with angular distributions and total cross sections as a function of neutron energy. The ratio pi-:pi+ was found to increase rapidly with decreasing neutron energy and the pion production was found to increase approximately as A2/3 for the different targets. C1 UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131. UNIV COLORADO,BOULDER,CO 80309. RP BROOKS, ML (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 14 TC 4 Z9 4 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2343 EP 2354 DI 10.1103/PhysRevC.45.2343 PG 12 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100031 ER PT J AU WESTPHAL, AJ PRICE, PB SNOWDENIFFT, DP AF WESTPHAL, AJ PRICE, PB SNOWDENIFFT, DP TI UPPER LIMIT ON THE CROSS-SECTION FOR NUCLEAR-CHARGE PICKUP BY RELATIVISTIC URANIUM IONS SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-IONS; ATOMIC-COLLISIONS AB We have searched for examples of nuclear charge pickup by relativistic uranium ions in targets of both uranium and phosphate glass. We find none, which allows us to set an upper limit of 7.7 mb per target atom at the 90% confidence level on the cross section for this process. An extrapolation of the approximately quadratic dependence on projectile charge of the cross section for charge pickup predicts a cross section which would be approximately 10 times larger. This breakdown in the scaling can be understood by the propensity of the actinides to fission upon the deposition of sufficient excitation energy. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV NUCL SCI, BERKELEY, CA 94720 USA. RP WESTPHAL, AJ (reprint author), UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. NR 14 TC 20 Z9 20 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 EI 1089-490X J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2423 EP 2426 DI 10.1103/PhysRevC.45.2423 PG 4 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100040 ER PT J AU BARRETTE, J BELLWIED, R BRAUNMUNZINGER, P CLELAND, WE DAVID, G DEE, J DIETZSCH, O DUEK, E FATYGA, M FOX, D GREENE, SV HALL, JR HEMMICK, TK HERRMANN, N HOGUE, RW HONG, B JAYANANDA, K KRAUS, D KUMAR, BS LACASSE, R LISSAUER, D LLOPE, WJ LUDLAM, T MAJKA, R MAKOWIECKI, D MARK, SK MCCORKLE, S MITCHELL, JT MUTHUSWAMY, M OBRIEN, E POLYCHRONAKOS, V PRUNEAU, C ROTONDO, FS SANDWEISS, J SIMONGILLO, J SONNADARA, U STACHEL, J TAKAI, H TAKAGUI, EM THROWE, TG WATERS, L WILLIS, WJ WINTER, C WOLF, K WOLFE, D WOODY, CL XU, N ZHANG, Y ZHANG, Z ZOU, Z AF BARRETTE, J BELLWIED, R BRAUNMUNZINGER, P CLELAND, WE DAVID, G DEE, J DIETZSCH, O DUEK, E FATYGA, M FOX, D GREENE, SV HALL, JR HEMMICK, TK HERRMANN, N HOGUE, RW HONG, B JAYANANDA, K KRAUS, D KUMAR, BS LACASSE, R LISSAUER, D LLOPE, WJ LUDLAM, T MAJKA, R MAKOWIECKI, D MARK, SK MCCORKLE, S MITCHELL, JT MUTHUSWAMY, M OBRIEN, E POLYCHRONAKOS, V PRUNEAU, C ROTONDO, FS SANDWEISS, J SIMONGILLO, J SONNADARA, U STACHEL, J TAKAI, H TAKAGUI, EM THROWE, TG WATERS, L WILLIS, WJ WINTER, C WOLF, K WOLFE, D WOODY, CL XU, N ZHANG, Y ZHANG, Z ZOU, Z TI ELECTROMAGNETIC DISSOCIATION OF RELATIVISTIC SI-28 INTO P+AL-27 SO PHYSICAL REVIEW C LA English DT Article ID FRAGMENTATION CROSS-SECTIONS; DIPOLE RESONANCE; HEAVY-IONS; NUCLEON; EMISSION; READOUT AB We report a direct measurement of the final-state energy spectrum in the electromagnetic dissociation of Si-28 into p + Al-27 at an energy of 14.6 GeV/nucleon. The final-state energy is obtained through a calculation of the p-Al-27 invariant mass in kinematically reconstructed events. The final-state energy spectrum for all targets is peaked near the isovector giant-dipole resonance in Si-28 and the dependence of the magnitude of the cross section on target charge confirms that the excitation is largely electromagnetic. By exploiting the expected scaling behavior on target Z and A, the background from nuclear interactions is evaluated and subtracted, leaving a pure electromagnetic dissociation final-state energy distribution. This distribution is well reproduced by simulated events, in which the photon spectrum calculated in the Weiszacker-Williams approximation is combined with experimental data on the photonuclear reaction Si-28(gamma, p)Al-27, and slight differences are observed only at low final-state energy. C1 CERN,EUROPEAN ORG NUCL RES,CH-1211 GENEVA 23,SWITZERLAND. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. MCGILL UNIV,MONTREAL H3A 2T5,QUEBEC,CANADA. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. UNIV PITTSBURGH,PITTSBURGH,PA 15260. SUNY STONY BROOK,STONY BROOK,NY 11794. UNIV SAO PAULO,SAO PAULO,BRAZIL. TEXAS A&M UNIV SYST,COLLEGE STN,TX 77843. YALE UNIV,NEW HAVEN,CT 06520. RP BARRETTE, J (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Sonnadara, Upul/E-6359-2010; Takai, Helio/C-3301-2012 OI Takai, Helio/0000-0001-9253-8307 NR 18 TC 13 Z9 13 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2427 EP 2437 DI 10.1103/PhysRevC.45.2427 PG 11 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100041 ER PT J AU KRAKAUER, DA TALAGA, RL ALLEN, RC CHEN, HH HAUSAMMANN, R LEE, WP MAHLER, HJ LU, XQ WANG, KC BOWLES, TJ BURMAN, RL CARLINI, RD COCHRAN, DRF DOE, PJ FRANK, JS PIASETZKY, E POTTER, ME SANDBERG, VD AF KRAKAUER, DA TALAGA, RL ALLEN, RC CHEN, HH HAUSAMMANN, R LEE, WP MAHLER, HJ LU, XQ WANG, KC BOWLES, TJ BURMAN, RL CARLINI, RD COCHRAN, DRF DOE, PJ FRANK, JS PIASETZKY, E POTTER, ME SANDBERG, VD TI EXPERIMENTAL-STUDY OF NEUTRINO ABSORPTION ON CARBON SO PHYSICAL REVIEW C LA English DT Article ID REACTION CROSS-SECTIONS; C-12; DETECTOR AB The process of electron emission from - 30 MeV neutrino absorption on carbon, C-12(nu(e) e-)N-12, has been observed. The flux-weighted total cross section for the exclusive neutrino-induced nuclear transition C-12(nu(e), e-)N-12(g.s.) is [1.05 +/- 0.10(stat) +/- 0.10(syst)] X 10-(14) cm2 . The measured cross section and angular distribution d-sigma/d-OMEGA are in agreement with theoretical estimates. The inclusive nu(e), C-12 reaction rate, which accounted for the majority of all neutrino interactions observed in this experiment, was determined from a detailed fit of energy and angular distributions for the observed electrons. The inclusive C-12(nu(e), e-)X cross section is measured to be [1.41 +/- 0.23(tot)]X 10(-41) cm2. An upper limit for the sum of the C-13(nu(e),e-)X + Al-27(nu(e), e-)X inclusive absorption cross sections is presented. C1 UNIV CALIF IRVINE,IRVINE,CA 92717. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. TEL AVIV UNIV,IL-69978 TEL AVIV,ISRAEL. RP KRAKAUER, DA (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 25 TC 55 Z9 55 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 MAY PY 1992 VL 45 IS 5 BP 2450 EP 2463 DI 10.1103/PhysRevC.45.2450 PG 14 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100044 ER PT J AU FRICKE, SH ESBENSEN, H LANDOWNE, S AF FRICKE, SH ESBENSEN, H LANDOWNE, S TI ELASTIC-SCATTERING AND FUSION CALCULATIONS FOR O-16+CU-63, CU-65 SO PHYSICAL REVIEW C LA English DT Note ID COUPLED-CHANNELS CALCULATIONS; SYSTEMS AB Coupled channels calculations that simultaneously predict elastic scattering and fusion reaction cross sections are compared with the corresponding available measurements for O-16 + Cu-63, Cu-65 collisions. The calculations can reproduce the main features of the fusion and elastic scattering data sets but only separately by using significantly different ion-ion potentials. C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. RP FRICKE, SH (reprint author), UNIV DALLAS,DEPT PHYS,IRVING,TX 75062, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1992 VL 45 IS 5 BP 2500 EP 2502 DI 10.1103/PhysRevC.45.2500 PG 3 WC Physics, Nuclear SC Physics GA HU021 UT WOS:A1992HU02100050 ER PT J AU STRAUB, PB JAFFE, DE GLASS, HD ADAMS, MR BROWN, CN CHARPAK, G COOPER, WE CRITTENDEN, JA FINLEY, DA GRAY, R HEMMI, Y HSIUNG, YB HUBBARD, JR JONCKHEERE, AM JOSTLEIN, H KAPLAN, DM LEDERMAN, LM LUK, KB MAKI, A MANGEOT, P MCCARTHY, RL MIYAKE, K PLAAG, RE RUTHERFOORD, JP SAKAI, Y SANTIARD, JC SAULI, F SMITH, SR YOSHIDA, T YOUNG, KK AF STRAUB, PB JAFFE, DE GLASS, HD ADAMS, MR BROWN, CN CHARPAK, G COOPER, WE CRITTENDEN, JA FINLEY, DA GRAY, R HEMMI, Y HSIUNG, YB HUBBARD, JR JONCKHEERE, AM JOSTLEIN, H KAPLAN, DM LEDERMAN, LM LUK, KB MAKI, A MANGEOT, P MCCARTHY, RL MIYAKE, K PLAAG, RE RUTHERFOORD, JP SAKAI, Y SANTIARD, JC SAULI, F SMITH, SR YOSHIDA, T YOUNG, KK TI PARTICLE RATIOS OF HIGH-XT HADRONS IN P-A INTERACTIONS AT ROOT-S=38.8 GEV SO PHYSICAL REVIEW D LA English DT Article ID IMAGING CHERENKOV COUNTER; LARGE-TRANSVERSE-MOMENTUM; S = 27.4; NUCLEUS COLLISIONS; DIQUARK SCATTERING; CROSS-SECTIONS; IDENTIFICATION; PROGRESS; ISR AB We report measurements of the ratios K+/pi+, p/pi+, K-/pi-, pBAR/pi-, pi-/pi+, K-/K+, and pBAR/p for hadrons with 0.19 < x(t) < 0.62 produced in p-Be and p-W collisions at square-root s = 38.8 GeV. The K+/pi+ ratio at high X(t) gives the fragmentation-function ratio D(u)K+/D(u)pi+ at high z. The high-x(t) K-/pi- ratio gives an upper limit for D(d)K-/D(d)pi- at high z. The p(t) dependence of p/pi+ suggests that scattered constituent diquarks are the primary source of protons with p(t) < 6 GeV/c. We also present species correlations in high-mass h+h- pairs. Strong K+K- and ppBAR correlations were observed. C1 CENS,F-91190 GIF SUR YVETTE,FRANCE. CERN,CH-1211 GENEVA 23,SWITZERLAND. COLUMBIA UNIV,NEW YORK,NY 10027. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. KEK NAT LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 305,JAPAN. KYOTO UNIV,KYOTO 606,JAPAN. SUNY STONY BROOK,STONY BROOK,NY 11794. RP STRAUB, PB (reprint author), UNIV WASHINGTON,SEATTLE,WA 98195, USA. NR 15 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 1 PY 1992 VL 45 IS 9 BP 3030 EP 3037 DI 10.1103/PhysRevD.45.3030 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HR126 UT WOS:A1992HR12600004 ER PT J AU SAKUMOTO, WK DEBARBARO, P BODEK, A BUDD, HS KIM, BJ MERRITT, FS OREGLIA, MJ SCHELLMAN, H SCHUMM, BA BACHMANN, KT BLAIR, RE FOUDAS, C KING, BJ LEFMANN, WC LEUNG, WC MISHRA, SR OLTMAN, E QUINTAS, PZ RABINOWITZ, SA SCIULLI, F SELIGMAN, WG SHAEVITZ, MH BERNSTEIN, RH BORCHERDING, FO FISK, HE LAMM, MJ MARSH, W MERRITT, KW RAPIDIS, PA YOVANOVITCH, D SANDLER, PH SMITH, WH AF SAKUMOTO, WK DEBARBARO, P BODEK, A BUDD, HS KIM, BJ MERRITT, FS OREGLIA, MJ SCHELLMAN, H SCHUMM, BA BACHMANN, KT BLAIR, RE FOUDAS, C KING, BJ LEFMANN, WC LEUNG, WC MISHRA, SR OLTMAN, E QUINTAS, PZ RABINOWITZ, SA SCIULLI, F SELIGMAN, WG SHAEVITZ, MH BERNSTEIN, RH BORCHERDING, FO FISK, HE LAMM, MJ MARSH, W MERRITT, KW RAPIDIS, PA YOVANOVITCH, D SANDLER, PH SMITH, WH TI MEASUREMENT OF TEV MUON ENERGY-LOSS IN IRON SO PHYSICAL REVIEW D LA English DT Article ID 10 TEV AB We measure the energy loss of high-energy muons (up to 1 TeV) from cosmic-ray muons incident on the iron-scintillator calorimeter of the Chicago-Columbia-Fermilab-Rochester Collaboration (Lab E) neutrino detector at Fermilab. Measurements of the differential energy loss spectra in Fe and the average dE/dx energy loss in Fe are presented as functions of muon energy and are compared against calculations. There is reasonable agreement between the measurements and calculations except in the region of small energy losses (under a few GeV) for 1-TeV muons, where the measurement is about 30% lower than the calculation. This level of agreement with theory implies that reliable simulations of the performance of muon detectors for future TeV colliders can be done. C1 UNIV WISCONSIN,MADISON,WI 53706. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP SAKUMOTO, WK (reprint author), UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627, USA. OI Bernstein, Robert/0000-0002-7610-950X NR 21 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 1 PY 1992 VL 45 IS 9 BP 3042 EP 3050 DI 10.1103/PhysRevD.45.3042 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HR126 UT WOS:A1992HR12600006 ER PT J AU CARTER, MD BATCHELOR, DB JAEGER, EF AF CARTER, MD BATCHELOR, DB JAEGER, EF TI ELECTROMOTIVE EXCITATION OF A PLASMA SHEATH SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID IMPURITY PRODUCTION; ANTENNAS; EDGE AB The heating of the electrons in a plasma by radio frequency (rf) fields results in an electron distribution function that can be highly non-Maxwellian. The response of these heated electrons can lead to a substantially larger total potential drop than that obtained by arbitrarily choosing a single-temperature parameter to describe the electron distribution in a traditional Boltzmann approximation. Electromotively driven rf fields can have scale lengths along a static magnetic field line that are much larger than a Debye length and produce electron-sheath interactions that are best described as collisions. Estimates of the floating potential of a plasma that is excited by electromotively driven rf plasma currents parallel to a strong static magnetic field have been made using a Fermi acceleration heating model and linear estimates for the rf fields with plasma. When this non-Maxwellian distribution function is used for estimates of the static potential, the results show that the total potential drop is proportional to the rf oscillation energy and the square root of the ion to electron mass ratio. Numerical solutions to Poisson's equation are presented for non-Boltzmann electrons. Analytic estimates of parasitic rf power absorption and edge profile modification using a Bohm diffusion model are presented. Estimates for a purely electrostatic heating operator with rf fields that are assumed to scale as the Debye length along static magnetic field lines are also made for comparison with the electromagnetic result. RP CARTER, MD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 23 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1081 EP 1091 DI 10.1063/1.860466 PG 11 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900002 ER PT J AU ARTUN, M TANG, WM AF ARTUN, M TANG, WM TI GYROKINETIC ANALYSIS OF ION TEMPERATURE-GRADIENT MODES IN THE PRESENCE OF SHEARED FLOWS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID EDGE ELECTRIC-FIELD; H TRANSITION; TOKAMAK; TRANSPORT; PLASMAS AB The linearized gyrokinetic equation governing electrostatic microinstabilities in the presence of sheared equilibrium flows in both the z and y directions has been systematically derived for a sheared slab geometry, where in the large-aspect-ratio limit z and y directions correspond to the toroidal and poloidal directions, respectively. In the familiar long perpendicular wavelength regime (k(perpendicular-to)rho(i) < 1), the analysis leads to a comprehensive kinetic differential eigenmode equation that is solved numerically. The numerical results have been successfully cross-checked against analytic estimates in the fluid limit. For typical conditions, the ion temperature gradient (eta(i)) modes are found to be stabilized for y direction flows with a velocity shear scale comparable to that of the ion temperature gradient and velocities of a few percent of the sound speed. Sheared flows in the z direction taken alone are usually destabilizing, with the effect being independent of the sign of the flow. However, when both types are simultaneously considered, it is found that in the presence of sheared z-direction flow, sheared y-direction flow can be either stabilizing or destabilizing depending on the relative sign of these flows. However, for sufficiently large values of v(y)' the mode is completely stabilized regardless of the sign of v(z)'v(y)'. The importance of a proper kinetic treatment of this problem is supported by comparisons with fluid estimates. In particular, when such effects are favorable, significantly smaller values of sheared y-direction flow are required for stability than fluid estimates would indicate. RP ARTUN, M (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 17 TC 57 Z9 59 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1102 EP 1114 DI 10.1063/1.860118 PG 13 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900004 ER PT J AU NAKAJIMA, N CHENG, CZ OKAMOTO, M AF NAKAJIMA, N CHENG, CZ OKAMOTO, M TI HIGH-N HELICITY-INDUCED SHEAR ALFVEN EIGENMODES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAGNETOHYDRODYNAMIC MODES; PLASMA; INSTABILITY; SPECTRUM; PHYSICS; DESIGN; LIMIT AB The high-n helicity-induced shear Alfven eigenmodes (HAE) are considered both analytically and numerically for the straight helical magnetic system, where n is the toroidal mode number. The eigenmode equation for the high-n HAE modes is derived along the field line and, with the aid of the averaging method, is shown to reduce to the Mathieu equation asymptotically. The discrete HAE modes are shown to exist inside the continuum spectrum gaps. The continuous spectrum gaps appear around omega-2 = omega(A)2 [N(l(tau) - m)/2]2 for N = 1,2,..., where omega(A) is the toroidal Alfven transit frequency, and l, m, and tau are the polarity of helical coils, the toroidal pitch number of helical coils, and the rotational transform, respectively. For the same omega(A) and tau, the frequency of the helical continuum gap is larger than that of the continuum gap in tokamak plasmas by \l - tau--1(m)\. The polarity of helical coils l plays a crucial role in determining the spectrum gaps and the properties of the high-n HAE modes. The spectrum gaps near the magnetic axis are created by the helical ripple with circular flux surfaces for l = 1, and greater-than-or-equal-to 3 helicals. For l = 2 helical systems, the spectrum gaps are created by the ellipticity of the flux surfaces. These analytical results for the continuum gaps and the existence of the high-n HAE modes in the continuum gaps are confirmed numerically for the l = 2 case, and it is found that the HAE modes exist for mode structures with the even and the odd parities. C1 PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP NAKAJIMA, N (reprint author), NATL INST FUS SCI,NAGOYA 46401,JAPAN. RI Cheng, Chio/K-1005-2014 NR 23 TC 42 Z9 42 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1115 EP 1121 DI 10.1063/1.860119 PG 7 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900005 ER PT J AU BRIZARD, A AF BRIZARD, A TI NONLINEAR GYROFLUID DESCRIPTION OF TURBULENT MAGNETIZED PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID GYROKINETIC PARTICLE SIMULATION; GRADIENT-DRIVEN TURBULENCE; NUMERICAL-SIMULATION; MODE TURBULENCE; DRIFT MODES; MAGNETOHYDRODYNAMIC EQUATIONS; ELECTROMAGNETIC-WAVES; FLUID EQUATIONS; TOKAMAKS; TRANSPORT AB Nonlinear gyrofluid equations are obtained from the gyrocenter-fluid moments of the nonlinear gyrokinetic Vlasov equation, which describes an equilibrium magnetized nonuniform plasma perturbed by electromagnetic field fluctuations (delta-phi,delta-A(parallel-to),delta-B(parallel-to)), whose space-time scales satisfy the gyrokinetic ordering: omega much less than OMEGA(i), \k(parallel-to)\/k(perpendicular-to) much less than 1, and epsilon(perpendicular-to) = (k(perpendicular-to)rho(i)2 is-approximately-equal-to O(1). These low-frequency (reduced) fluid equations contain terms of arbitrary order in epsilon(perpendicular-to) and take into account the nonuniformity in the equilibrium density and temperature of the ion and electron species, as well as the nonuniformity in the equilibrium magnetic field. From the gyrofluid equations, one can systematically derive nonlinear reduced fluid equations with finite-Larmor-radius (FLR) corrections, which contain linear and nonlinear terms of O(epsilon(perpendicular-to), by expressing the gyrocenter-fluid moments appearing in the gyrofluid equations in terms of the particle-fluid moments, and then keeping terms up to O(epsilon(perpendicular-to)) in the epsilon(perpendicular-to) expansion of the gyrofluid equations. By using gyrocenter-fluid moments, this new gyrofluid approach effectively bypasses the issue of the gyroviscous cancellations, while retaining all the important diamagnetic effects and the gyroviscous corrections. From the present FLR-corrected reduced fluid equations, the reduced Braginskii equations are recovered for the ion and electron species (without collisional dissipation) and the ideal reduced magnetohydrodynamic (MHD) equations (in the absence of FLR effects). RP BRIZARD, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. OI Brizard, Alain/0000-0002-0192-6273 NR 50 TC 86 Z9 86 U1 1 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1213 EP 1228 DI 10.1063/1.860129 PG 16 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900015 ER PT J AU MYNICK, HE AF MYNICK, HE TI ANOMALOUS ENERGY EXCHANGE IN THE GBL AND QUASI-LINEAR THEORIES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID LENARD COLLISION OPERATOR; TRANSPORT; DIFFUSION; PLASMA AB The rate of turbulence-induced energy exchange W0 between species is computed in the framework of the quasilinear and generalized Balescu-Lenard (gBL) transport theories, and the relationship between these two similar theories is thereby elucidated. For both theories, general formal expressions for W0 are developed and then applied to the trapped electron mode for illustration. The general expressions for W0 in the two theories are formally closely related, but can yield predictions of very different magnitude in concrete applications. The fact that quasilinear theory is not valid for saturated steady-state turbulence gives rise to certain peculiarities in its predictions for this normal experimental situation, such as permitting energy to flow from the cooler to the hotter species, even in the limit of thermal equilibrium, where real-space gradients vanish. The gBL theory may be viewed as a modification of quasilinear theory to be valid for steady-state turbulence, keeping extra terms due to the self-consistent back reaction of particles on the fluctuations, which are just such as to eliminate these peculiarities. RP PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. NR 18 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1229 EP 1237 DI 10.1063/1.860130 PG 9 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900016 ER PT J AU FINN, JM NEBEL, R BATHKE, C AF FINN, JM NEBEL, R BATHKE, C TI SINGLE AND MULTIPLE HELICITY OHMIC STATES IN REVERSED-FIELD PINCHES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAGNETIC RECONNECTION; SELF-REVERSAL; DRIVEN; FLUCTUATIONS; SIMULATION; MODEL; FLOWS AB The properties of single helicity and multiple helicity Ohmic states in reversed-field pinches (RFP's) are investigated by a combination of analytic and numerical methods. The single helicity results show that toroidal field reversal can be provided in a helical Ohmic equilibrium driven by a toroidal loop voltage, and that reversal in helical symmetry is related to stellarator transform. Nevertheless, a constant lambda = j(parallel-to)/B state cannot be sustained because lambda must reverse at the toroidal field reversal surface. This helical equilibrium can be thought of as the saturated state of an unstable tearing mode. For a force-free plasma, helical reversal can be maintained by a relatively small value of beta-B/B because it is accompanied by an inward paramagnetic pinch velocity. Conversely, in models with del.v = O, a large outward diffusive velocity must build up to balance the inward paramagnetic pinch velocity, requiring poloidal beta to be of order unity. It is shown that in three dimensions no multihelical Ohmic equilibrium can exist if there is an area of destroyed flux surfaces. Numerical simulations in three dimensions (3D) indeed show that Ohmic states exist, but with fields varying on a resistive time scale. Also, a bifurcation is found between two distinct classes of solutions in 3D. The first is a broad spectrum multihelical state with almost no flux surfaces. The other class consists of narrow spectrum nearly single helicity states with a large fraction of the plasma volume occupied by good flux surfaces. The existence of this second class of states indicates the possibility of operating RFP's in a single helicity mode with good flux surfaces. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP FINN, JM (reprint author), UNIV MARYLAND,PLASMA RES LAB,COLLEGE PK,MD 20742, USA. NR 36 TC 87 Z9 87 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1262 EP 1279 DI 10.1063/1.860082 PG 18 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900020 ER PT J AU RAX, JM FISCH, NJ AF RAX, JM FISCH, NJ TI NONLINEAR RELATIVISTIC INTERACTION OF AN ULTRASHORT LASER-PULSE WITH A COLD-PLASMA SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID BEAT-WAVE ACCELERATOR; AMPLIFICATION AB The nonlinear, relativistic dynamics that results when intense (10(18) W/cm-2 and above) and ultrashort (one plasma period or shorter) laser pulse travels through a cold underdense plasma is investigated. Using a Lagrangian analysis of the plasma response, it can be demonstrated that the nonlinear wake, the collective dissipation, the nonlinear Compton losses, and the harmonic generation, are all determined by a finite set of integrated scalar quantities. This result holds for one-dimensional, short pulses of arbitrary amplitude, shape, and polarization, so that these very short intense laser pulses in a plasma can be viewed essentially as a quasiparticle characterized by a small set of global parameters. C1 CEN CADARACHE,CEA,ASSOC EURATOM,F-13108 ST PAUL DURANCE,FRANCE. RP RAX, JM (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 28 TC 27 Z9 27 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1323 EP 1331 DI 10.1063/1.860087 PG 9 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900025 ER PT J AU SLUTZ, SA JOHNSON, WA AF SLUTZ, SA JOHNSON, WA TI THE EFFECT OF A VIRTUAL CATHODE ON THE ELECTROMAGNETIC STABILITY OF HIGH-POWER ION DIODES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAGNETICALLY INSULATED GAPS; NEUTRAL ELECTRON FLOW; INSTABILITIES; EQUILIBRIUM; FIELD AB Previous stability analyses have shown magnetically insulated ion diode equilibria to be unstable. However, important equilibrium features such as a virtual-cathode and a charge-neutral region were not included. A stability analysis including these features is presented, which indicates that the stability behavior is strongly affected by the equilibrium model. In particular, the diocotron instability displaces the ion resonance instability found in the previous analyses. The calculated growth rates for the diocotron mode are consistent with a fast growing mode that has been observed in recently reported three-dimensional numerical simulations. These simulations exhibit a transition from the diocotron to an ion resonance mode and a subsequent increase in ion divergence due to the much lower frequency of the ion mode. The stability analysis presented in this paper demonstrates bow the evolution of the electron sheath reduces the diocotron growth rate resulting in unstable ion modes, thus explaining the transition to ion modes observed in the simulations. RP SLUTZ, SA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 27 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1349 EP 1359 DI 10.1063/1.860089 PG 11 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900027 ER PT J AU RATH, S SRIDHAR, S AF RATH, S SRIDHAR, S TI CORE INSTABILITY OF ELLIPTIC DRIFT VORTICES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Note ID PLASMA AB It is shown that two-dimensional drift vortices with elliptic cores are unstable to certain short-wavelength three-dimensional perturbations. Circular vortices are stable to those modes. At short wavelengths, the growth rate is independent of the wavelength and, for small ellipticity, it is proportional to the ellipticity. C1 CALTECH,PASADENA,CA 91125. RP RATH, S (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1367 EP 1369 DI 10.1063/1.860091 PG 3 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900031 ER PT J AU SMITH, RA ONEIL, TM LUND, SM RAMOS, JJ DAVIDSON, RC AF SMITH, RA ONEIL, TM LUND, SM RAMOS, JJ DAVIDSON, RC TI COMMENT ON THE STABILITY THEOREM OF DAVIDSON AND LUND SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Note C1 MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP SMITH, RA (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093, USA. NR 2 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAY PY 1992 VL 4 IS 5 BP 1373 EP 1373 DI 10.1063/1.860094 PG 1 WC Physics, Fluids & Plasmas SC Physics GA HR929 UT WOS:A1992HR92900034 ER PT J AU MATTIS, MP AF MATTIS, MP TI THE RIDDLE OF HIGH-ENERGY BARYON NUMBER VIOLATION SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID WEINBERG-SALAM THEORY; QUANTITATIVE THEORY; QUANTUM CHROMODYNAMICS; INSTANTON LIQUID; ELECTROWEAK INTERACTIONS; PERTURBATION-THEORY; GAUGE-THEORIES; BREAKDOWN; VACUUM; QCD AB The exciting possibility that anomalous baryon and lepton number violation, might be observable at the next generation of supercolliders is suggested by an instanton calculation due to Ringwald and Espinosa. In this review, the current controversial status of these claims is discussed, and several new technologies designed to analyze this question are reviewed. These technologies should contribute more generally to our understanding of weakly-coupled field theories in the nonperturbative regime where both energies and multiplicities are very large. RP MATTIS, MP (reprint author), LOS ALAMOS NATL LAB,DIV THEORET T-8,LOS ALAMOS,NM 87545, USA. NR 93 TC 96 Z9 96 U1 1 U2 1 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 MAY PY 1992 VL 214 IS 3 BP 159 EP 221 DI 10.1016/0370-1573(92)90033-V PG 63 WC Physics, Multidisciplinary SC Physics GA HX171 UT WOS:A1992HX17100001 ER PT J AU HAYTER, JB AF HAYTER, JB TI UNITED-STATES NEUTRON PLENITUDE SO PHYSICS WORLD LA English DT Letter RP HAYTER, JB (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 TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8585 J9 PHYS WORLD JI Phys. World PD MAY PY 1992 VL 5 IS 5 BP 18 EP 18 PG 1 WC Physics, Multidisciplinary SC Physics GA HU210 UT WOS:A1992HU21000020 ER PT J AU TSUJI, J SOMERVILLE, SC AF TSUJI, J SOMERVILLE, SC TI 1ST REPORT OF NATURAL INFECTION OF ARABIDOPSIS-THALIANA BY XANTHOMONAS-CAMPESTRIS PV CAMPESTRIS SO PLANT DISEASE LA English DT Note C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. NR 0 TC 11 Z9 11 U1 0 U2 2 PU AMER PHYTOPATHOLOGICAL SOC PI ST PAUL PA 3340 PILOT KNOB ROAD, ST PAUL, MN 55121 SN 0191-2917 J9 PLANT DIS JI PLANT DIS. PD MAY PY 1992 VL 76 IS 5 BP 539 EP 539 PG 1 WC Plant Sciences SC Plant Sciences GA HP213 UT WOS:A1992HP21300031 ER PT J AU HUGLY, S SOMERVILLE, C AF HUGLY, S SOMERVILLE, C TI A ROLE FOR MEMBRANE LIPID POLYUNSATURATION IN CHLOROPLAST BIOGENESIS AT LOW-TEMPERATURE SO PLANT PHYSIOLOGY LA English DT Article ID GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE ACTIVITY; ENHANCED THERMAL TOLERANCE; ARABIDOPSIS DEFICIENT; PALMITIC ACID; HIGHER-PLANTS; LEAF LIPIDS; MUTANT; DESATURATION; STABILITY; FLUIDITY AB Two different mutants of Arabidopsis thaliana deficient in chloroplast membrane lipid polyunsaturation were indistinguishable in appearance from the wild-type when grown at 22-degrees-C. By contrast, leaf tissues of the mutants that developed during growth at 5-degrees-C were chlorotic, whereas the wild type was not. This is the first direct evidence that chloroplast lipid polyunsaturation contributes to low-temperature fitness. Chloroplasts from mutant lines grown at 5-degrees-C were much smaller than those of the wild-type, and the thylakoid membrane content was reduced by up to 70%. However, there was no discernible effect of low temperature on chloroplasts that developed prior to exposure to low temperatures. These and related observations suggest that the high degree of chloroplast membrane lipid polyunsaturation is required for some aspect of chloroplast biogenesis. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. RI Somerville, Christopher/A-4048-2009 OI Somerville, Christopher/0000-0003-4647-0094 NR 19 TC 103 Z9 119 U1 0 U2 2 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1992 VL 99 IS 1 BP 197 EP 202 DI 10.1104/pp.99.1.197 PG 6 WC Plant Sciences SC Plant Sciences GA HU485 UT WOS:A1992HU48500029 PM 16668849 ER PT J AU KREPS, JA TOWN, CD AF KREPS, JA TOWN, CD TI ISOLATION AND CHARACTERIZATION OF A MUTANT OF ARABIDOPSIS-THALIANA RESISTANT TO ALPHA-METHYLTRYPTOPHAN SO PLANT PHYSIOLOGY LA English DT Article ID ANTHRANILATE SYNTHETASE; CELLS; PLANTS; SELECTION; FORMS AB Mutants of Arabidopsis thaliana have been selected for resistance to growth inhibition at the seedling stage by alpha-methyltryptophan (aMT). One mutant amt-1 has been characterized in detail. The appearance and growth rate of the mutant in the absence of the inhibitor are similar to wild type, both as plants and callus. However, mutant plant growth is unaffected by 25 micromolar aMT and mutant callus growth by 50 micromolar aMT, concentrations that completely inhibit the growth of wild-type plants and callus, respectively. Tryptophan levels in mutant and wild-type plants are 24.3 +/- 2.7 and 4.7 +/- 1.2 micrograms per gram fresh weight, respectively, and in the corresponding callus 64.0 +/- 2.6 and 31.8 +/- 8.4 micrograms per gram fresh weight, respectively. Anthranilate synthase (AS) activity levels in crude extracts from whole plants are 3.09 +/- 0.54 nanomoles per milligram protein per hour in amt-1 and 1.32 +/- 0.21 nanomoles per milligram protein per hour in wild-type plants. In crude extracts from callus, anthranilate synthase levels are 11.54 +/- 2.05 nanomoles per milligram protein per hour and 7.74 +/- 1.58 in amt-1 and wild type, respectively. Enzyme extracts are inhibited by L-tryptophan; the concentrations required for 50% inhibition (I50) are 3.9 and 1.9 micromolar for amt-1 and for wild type, respectively. The mutation segregates as a single nuclear allele and shows incomplete dominance. The concomitant increases in both AS activity and its I50 for tryptophan suggest that the mutation amt-1 either resides in one of the AS structural genes or causes increased expression of an AS isoform with an I50 greater than the average for the entire extract. C1 CASE WESTERN RESERVE UNIV,DEPT BIOL,CLEVELAND,OH 44106. MICHIGAN STATE UNIV,US DOE,PLANT BIOL LABS,E LANSING,MI 48824. NR 21 TC 26 Z9 26 U1 0 U2 0 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1992 VL 99 IS 1 BP 269 EP 275 DI 10.1104/pp.99.1.269 PG 7 WC Plant Sciences SC Plant Sciences GA HU485 UT WOS:A1992HU48500039 PM 16668861 ER PT J AU KAKEFUDA, G CHARNG, YY IGLESIAS, AA MCINTOSH, L PREISS, J AF KAKEFUDA, G CHARNG, YY IGLESIAS, AA MCINTOSH, L PREISS, J TI MOLECULAR-CLONING AND SEQUENCING OF ADP-GLUCOSE PYROPHOSPHORYLASE FROM SYNECHOCYSTIS PCC-6803 SO PLANT PHYSIOLOGY LA English DT Article ID BACTERIAL GLYCOGEN; BIOSYNTHESIS; SYNTHETASE C1 MICHIGAN STATE UNIV,DEPT BIOCHEM,E LANSING,MI 48824. MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. RI Charng, Yee-yung/F-3296-2015 OI Charng, Yee-yung/0000-0002-9107-3955 NR 10 TC 7 Z9 7 U1 0 U2 2 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1992 VL 99 IS 1 BP 359 EP 361 DI 10.1104/pp.99.1.359 PG 3 WC Plant Sciences SC Plant Sciences GA HU485 UT WOS:A1992HU48500056 PM 16668879 ER PT J AU DINI, JW AF DINI, JW TI PERSPECTIVE ON PLATING FOR PRECISION FINISHING SO PLATING AND SURFACE FINISHING LA English DT Article ID ELECTRODEPOSITION; NICKEL AB An overview of plating for precision finishing operations is given, followed by a brief review of the two processes (polishing and precision machining) by which a coating on a part can be converted to a precision surface. The coatings that work successfully in these applications are discussed, as well as their adhesion and stress aspects. Electroless nickel, a particularly attractive coating for precision finishing applications, is covered in some detail, from its early years as the "Kanigen" process, to the present. Because microstructural changes in deposits are important for precision parts, this aspect is covered for electroless nickel, copper and silver deposits. Finally, some thoughts are directed toward potential future electrodeposited coatings, including nickel-phosphorus alloys, and various silver alloys. RP DINI, JW (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV MAT FABRICAT,POB 808,LIVERMORE,CA 94550, USA. NR 46 TC 1 Z9 1 U1 0 U2 2 PU AMER ELECTROPLATERS SOC INC PI ORLANDO PA 12644 RESEARCH PKWY, ORLANDO, FL 32826-3298 SN 0360-3164 J9 PLAT SURF FINISH JI Plat. Surf. Finish. PD MAY PY 1992 VL 79 IS 5 BP 121 EP 128 PG 8 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA HT174 UT WOS:A1992HT17400010 ER PT J AU TALUKDAR, S RAMESH, VC QUADREL, R CHRISTIE, R AF TALUKDAR, S RAMESH, VC QUADREL, R CHRISTIE, R TI MULTIAGENT ORGANIZATIONS FOR REAL-TIME OPERATIONS SO PROCEEDINGS OF THE IEEE LA English DT Article AB The real-time operations of electric power networks are subject to two sets of forces. The first, including deregulation movements and growing environmental concerns, is acting to increase the complexity of operations. The second, including new computer technologies and emerging knowledge-based agents, provides some means for handling additional complexity. This paper argues that organizational changes will have to be made before the second set of forces can be applied to effectively counter the first. To make this argument, the paper presents a framework for discussing organizational structures. Then it reviews the structures of the two generations of computer-based, multiagent systems that have, been developed for operations. It points out that these structures are well-suited to the algorithmic tasks involved in operations but not to the knowledge-based tasks. The paper concludes with some suggestions for research into alternative structures. C1 PACIFIC NW LAB, MARINE RES LABS, SEQUIM, WA 98382 USA. UNIV WASHINGTON, DEPT ELECT ENGN, SEATTLE, WA 98105 USA. RP TALUKDAR, S (reprint author), CARNEGIE MELLON UNIV, ENGN DESIGN RES CTR, PITTSBURGH, PA 15213 USA. NR 72 TC 18 Z9 21 U1 4 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9219 J9 P IEEE JI Proc. IEEE PD MAY PY 1992 VL 80 IS 5 BP 765 EP 777 DI 10.1109/5.137231 PG 13 WC Engineering, Electrical & Electronic SC Engineering GA HV746 UT WOS:A1992HV74600012 ER PT J AU LU, KH CAMPISI, J AF LU, KH CAMPISI, J TI RAS PROTEINS ARE ESSENTIAL AND SELECTIVE FOR THE ACTION OF INSULIN-LIKE GROWTH FACTOR-I LATE IN THE G1-PHASE OF THE CELL-CYCLE IN BALB/C MURINE FIBROBLASTS SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE PROTOONCOGENES; SIGNAL TRANSDUCTION; GTP-BINDING PROTEIN; CELL CYCLE CONTROL; C-FOS ID MYC MESSENGER-RNA; C-FOS; XENOPUS OOCYTES; DNA-SYNTHESIS; PC12 CELLS; MICROINJECTION; EXPRESSION; DIFFERENTIATION; TRANSFORMATION; PROLIFERATION AB BALB/c 3T3 cells (A31 cells) require the sequential action of growth factors in order to proliferate from a quiescent growth state. Insulin-like growth factor I (IGF-I) is needed late in the G1 phase of the cell cycle, a time at which expression of the c-Ha-ras protooncogene is near maximal. An anti-ras antibody, introduced by microinjection, specifically blocked the ability of IGF-I to stimulate initiation of DNA synthesis. The antibody was specific for IGF-I; it failed to block serum, platelet-derived growth factor, or epidermal growth factor from inducing c-fos mRNA. By contrast, an anti-G alpha-subunit antibody had no effect on IGF-I-stimulated DNA synthesis but inhibited the induction of c-fos mRNA by platelet-derived growth factor or epidermal growth factor. BPA31 cells are tumorigenic A31-derived cells that progress through G, in the absence of IGF-I. BPA31 cells produced an autocrine IGF-I that was responsible for the loss of late G1 control; the anti-ras antibody arrested the growth of these cells in late G1. The results suggest that ras proteins are essential for an IGF-I-sensitive, G1 control point. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BLDG 83,BERKELEY,CA 94720. BOSTON UNIV,SCH MED,DEPT BIOCHEM,BOSTON,MA 02118. NR 31 TC 60 Z9 62 U1 0 U2 1 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 1 PY 1992 VL 89 IS 9 BP 3889 EP 3893 DI 10.1073/pnas.89.9.3889 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HR853 UT WOS:A1992HR85300045 PM 1570309 ER PT J AU BASS, MB PAULSEN, MD ORNSTEIN, RL AF BASS, MB PAULSEN, MD ORNSTEIN, RL TI SUBSTRATE MOBILITY IN A DEEPLY BURIED ACTIVE-SITE - ANALYSIS OF NORCAMPHOR BOUND TO CYTOCHROME-P-450(CAM) AS DETERMINED BY A 201-PSEC MOLECULAR-DYNAMICS SIMULATION SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE NORCAMPHOR; P450CIA1; SUBSTRATE SPECIFICITY ID PROTEIN; HYDROXYLATION; EQUILIBRIUM; REDUCTION; ISOMERASE; ENZYME; LOOP AB While cytochrome P-450(cam) catalyzes the hydroxylation of camphor to 5-exo-hydroxycamphor with 100% stereospecificity, norcamphor is hydroxylated by this enzyme yielding 45% 5-exo-, 47% 6-exo-, and 8% 3-exo-hydroxynorcamphor (Atkins, W.M., Sligar, S.G., J. Am. Chem. Soc. 109:3754-3760, 1987). The present study describes a 201-psec molecular dynamics (MD) simulation of norcamphor-bound cytochrome P-450cam to elucidate the relationship between substrate conformational mobility and formation of alternative products. First, these data suggest that the product specificity is, at least partially, due to the mobility of the substrate within the active site. Second, the high mobility of norcamphor in the active site leads to an average increase in separation between the heme iron and the substrate of about 1.0 angstrom; this increase in separation may be the cause of the uncoupling of electron transfer when norcamphor is the substrate. Third, the active site water located in the norcamphor-bound crystal structure possesses mobility that correlates well with the spin-state equilibrium of this enzyme-substrate complex. C1 PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. PACIFIC NW LAB, ENVIRONM SCI RES CTR, RICHLAND, WA 99352 USA. NR 30 TC 25 Z9 25 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-3585 J9 PROTEINS JI Proteins PD MAY PY 1992 VL 13 IS 1 BP 26 EP 37 DI 10.1002/prot.340130103 PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA HP212 UT WOS:A1992HP21200002 PM 1594575 ER PT J AU SOLARZ, RW KRUPKE, WF AF SOLARZ, RW KRUPKE, WF TI DIODE PUMPED LASERS FINDING COMMERCIAL APPLICATIONS SO R&D MAGAZINE LA English DT Article RP SOLARZ, RW (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CAHNERS-DENVER PUBLISHING CO PI HIGHLANDS RANCH PA 8773 S RIDGELINE BLVD, HIGHLANDS RANCH, CO 80126-2329 SN 0746-9179 J9 R&D MAG JI R D Mag. PD MAY PY 1992 VL 34 IS 6 BP 89 EP & PG 0 WC Engineering, Industrial; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA HV999 UT WOS:A1992HV99900022 ER PT J AU DUNPHY, EJ BECKETT, MA THOMPSON, LH WEICHSELBAUM, RR AF DUNPHY, EJ BECKETT, MA THOMPSON, LH WEICHSELBAUM, RR TI EXPRESSION OF THE POLYMORPHIC HUMAN DNA-REPAIR GENE-XRCC1 DOES NOT CORRELATE WITH RADIOSENSITIVITY IN THE CELLS OF HUMAN HEAD AND NECK TUMOR-CELL LINES SO RADIATION RESEARCH LA English DT Article ID SISTER CHROMATID EXCHANGE; RADIOBIOLOGICAL CHARACTERIZATION; GENE; RADIOTHERAPY; XRCC1 C1 UNIV CHICAGO,CTR RADIAT THERAPY,DEPT RADIAT & CELLULAR ONCOL,CHICAGO,IL 60615. LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. FU NCI NIH HHS [CA42596] NR 22 TC 16 Z9 16 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 820 JORIE BOULEVARD, OAK BROOK, IL 60523 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAY PY 1992 VL 130 IS 2 BP 166 EP 170 DI 10.2307/3578273 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA HV321 UT WOS:A1992HV32100004 PM 1574572 ER PT J AU MACKLIS, RM LIN, JY BERESFORD, B ATCHER, RW HINES, JJ HUMM, JL AF MACKLIS, RM LIN, JY BERESFORD, B ATCHER, RW HINES, JJ HUMM, JL TI CELLULAR KINETICS, DOSIMETRY, AND RADIOBIOLOGY OF ALPHA-PARTICLE RADIOIMMUNOTHERAPY - INDUCTION OF APOPTOSIS SO RADIATION RESEARCH LA English DT Article ID MONOCLONAL-ANTIBODY; TUMOR; LYMPHOMA; DAMAGE; MODEL C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DEPT BIOL,ARGONNE,IL 60439. RP MACKLIS, RM (reprint author), HARVARD UNIV,SCH MED,JOINT CTR RADIAT THERAPY,50 BINNEY ST,BOSTON,MA 02115, USA. OI Atcher, Robert/0000-0003-4656-2247 FU NCI NIH HHS [CA49017, CA50886] NR 26 TC 94 Z9 98 U1 0 U2 2 PU RADIATION RESEARCH SOC PI OAK BROOK PA 820 JORIE BOULEVARD, OAK BROOK, IL 60523 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAY PY 1992 VL 130 IS 2 BP 220 EP 226 DI 10.2307/3578279 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA HV321 UT WOS:A1992HV32100010 PM 1574578 ER PT J AU SWEATT, WC AF SWEATT, WC TI DEPTH OF FOCUS IN VELOCITY INTERFEROMETER SYSTEM FOR ANY REFLECTOR SYSTEMS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Velocity interferometer system for any reflector (VISARs) are used to measure the velocity of targets by monitoring the Doppler shift of laser light backscattered from them. In the design of these systems, there is a trade-off between signal-collecting efficiency and depth of focus. We present a VISAR architecture that maximizes the efficiency for any specified depth of focus for velocity sensitivities ranging from 20 m per second per fringe to several kilometers per second per fringe. We consider the usual system where the light going to and from the target is relayed with lenses. We also study fiber optically coupled systems. Our analysis shows that well-designed fiber-coupled systems can be as efficient as the equivalent lens-coupled systems, assuming that the divergence of the fiber-coupled laser beam is small. RP SWEATT, WC (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 5 TC 4 Z9 5 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 2945 EP 2949 DI 10.1063/1.1142591 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200006 ER PT J AU ROJAS, D SILVA, RJ RUSSO, RE AF ROJAS, D SILVA, RJ RUSSO, RE TI THERMAL LENS SPECTROSCOPY USING A DIODE-LASER AND OPTICAL FIBERS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ATOMIC-ABSORPTION SPECTROSCOPY; AQUEOUS-SOLUTION; TRACE ANALYSIS; SPECTROPHOTOMETRY; URANIUM AB A compact thermal lens spectrometer was developed using optical fibers and a diode laser for measurements of rare earth species in aqueous solutions. A cw GaAlAs diode laser coupled with a multimode step-index fiber was used as the excitation source. The thermal lens was probed with a He-Ne laser using a multimode 200-mu-m diameter core optical fiber as the aperture and to transmit the probe beam to the detector. The system was tested for the detection of Nd3+ in aqueous solutions at 794.6 nm. A sensitivity with detection limit of 79 +/- 4 M-1 and 8 X 10(-5) M was obtained for an incident power of 10 mW and a power density of 11 W/cm2. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV APPL SCI,MS 90-2024,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV NUCL CHEM,LIVERMORE,CA 94550. UNIV LOS ANDES,FAC CIENCIAS,DEPT QUIM,MERIDA 5101A,VENEZUELA. NR 24 TC 10 Z9 10 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 2989 EP 2993 DI 10.1063/1.1142597 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200013 ER PT J AU JENSEN, E BARTYNSKI, RA HULBERT, SL JOHNSON, ED AF JENSEN, E BARTYNSKI, RA HULBERT, SL JOHNSON, ED TI AUGER PHOTOELECTRON COINCIDENCE SPECTROSCOPY USING SYNCHROTRON RADIATION SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID VALENCE-VALENCE PROCESSES; X-RAY PHOTOEMISSION; ELECTRONIC-STRUCTURE; SIMPLE METALS; LINE-SHAPES; SURFACE; AL(111); OXYGEN AB The technique of Auger photoelectron coincidence spectroscopy (APECS) using synchrotron radiation is discussed. Technical considerations and experimental details are emphasized. Results from Cu(100), Ta(100), and Al(111) are presented to show the kinds of new information that APECS can provide. C1 RUTGERS STATE UNIV,DEPT PHYS,PISCATAWAY,NJ 08855. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973. RP JENSEN, E (reprint author), BRANDEIS UNIV,DEPT PHYS,WALTHAM,MA 02254, USA. NR 19 TC 53 Z9 53 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 3013 EP 3026 DI 10.1063/1.1142602 PG 14 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200018 ER PT J AU REYES, AP AHRENS, ET HEFFNER, RH HAMMEL, PC THOMPSON, JD AF REYES, AP AHRENS, ET HEFFNER, RH HAMMEL, PC THOMPSON, JD TI CUPROUS-OXIDE MANOMETER FOR HIGH-PRESSURE MAGNETIC-RESONANCE EXPERIMENTS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID CU2O AB We present a manometer designed to measure pressures of 1-20 kbar in temperatures between 4-300 K in cylinder-piston type chambers, with an accuracy of approximately 100 bar. The manometer is based on pressure-dependent zero-field Cu-63 nuclear quadrupole resonance frequency corresponding to \+/- 3/2] <-> \ +/- 1/2] transition in Cu2O. The nuclear quadrupole resonance frequency nu(Q) varies linearly with pressure and its temperature dependence is adequately explained by a model of lattice vibrational modes in O-Cu-O bonds. This manometer is particularly convenient for zero or high-field magnetic resonance experiments. RP REYES, AP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Hammel, P Chris/O-4845-2014 OI Hammel, P Chris/0000-0002-4138-4798 NR 18 TC 33 Z9 33 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 3120 EP 3122 DI 10.1063/1.1142564 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200033 ER PT J AU KUOKKALA, VT SCHWARZ, RB AF KUOKKALA, VT SCHWARZ, RB TI THE USE OF MAGNETOSTRICTIVE FILM TRANSDUCERS IN THE MEASUREMENT OF ELASTIC-MODULI AND ULTRASONIC-ATTENUATION OF SOLIDS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The authors describe a novel method and apparatus for measuring the elastic moduli and ultrasonic attenuation of small samples (millimeter dimensions) over a wide temperature range. In the most general case, a nonmagnetic sample is coated with a thin film of a magnetostrictive material (e.g., nickel or iron-cobalt alloy). This film performs both as a driving transducer and as a receiving transducer. An alternating magnetic field of variable frequency generates a periodic stress in the film and drives the sample into mechanical resonances. The permeability of the film changes when the sample is resonating and allows the detection of the resonances. The operation of the system and the mathematical procedures to deduce the elastic moduli and ultrasonic attenuation from the measured resonance spectra are exemplified with measurements on amorphous Ni80P20 in the temperature range of 80-520 K. C1 TAMPERE UNIV,INST MAT SCI,SF-33101 TAMPERE,FINLAND. RP KUOKKALA, VT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 15 TC 18 Z9 18 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 3136 EP 3142 DI 10.1063/1.1142566 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200036 ER PT J AU WISHART, JF VANELDIK, R AF WISHART, JF VANELDIK, R TI HIGH-PRESSURE PULSE-RADIOLYSIS - MODIFICATION OF AN OPTICAL-CELL FOR 2-MEV ELECTRON PULSE-RADIOLYSIS AT PRESSURES UP TO 200-MPA SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Note ID AQUEOUS-SOLUTIONS; ACTIVATION; MECHANISM; KINETICS AB The construction of a high-pressure cell for pulse-radiolysis experiments with 2-MeV electrons at pressures up to 200 MPa using optical UV-VIS detection is described. Details on the window construction are given, and typical results for the thiocyanate test system are presented. The cell enables systematic studies of the effect of pressure on pulse radiolytically induced reactions using lower energy accelerators than previously possible. C1 UNIV WITTEN HERDECKE,INST INORGAN CHEM,W-5810 WITTEN,GERMANY. RP WISHART, JF (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Wishart, James/L-6303-2013 OI Wishart, James/0000-0002-0488-7636 NR 16 TC 24 Z9 24 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1992 VL 63 IS 5 BP 3224 EP 3225 DI 10.1063/1.1142533 PG 2 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA HR942 UT WOS:A1992HR94200057 ER PT J AU CHARLSON, RJ SCHWARTZ, SE HALES, JM CESS, RD COAKLEY, JA HANSEN, JE HOFMANN, DJ AF CHARLSON, RJ SCHWARTZ, SE HALES, JM CESS, RD COAKLEY, JA HANSEN, JE HOFMANN, DJ TI AEROSOLS AND GLOBAL WARMING - RESPONSE SO SCIENCE LA English DT Letter C1 UNIV WASHINGTON, INST ENVIRONM STUDIES, SEATTLE, WA 98195 USA. BROOKHAVEN NATL LAB, DIV ENVIRONM CHEM, UPTON, NY 11973 USA. PACIFIC NW LAB, DEPT ATMOSPHER SCI, RICHLAND, WA 99352 USA. SUNY STONY BROOK, INST TERR & PLANETARY ATMOSPHERES, STONY BROOK, NY 11794 USA. OREGON STATE UNIV, DEPT ATMOSPHER SCI, CORVALLIS, OR 97331 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. RP CHARLSON, RJ (reprint author), UNIV WASHINGTON, DEPT ATMOSPHER SCI, SEATTLE, WA 98195 USA. RI Schwartz, Stephen/C-2729-2008 OI Schwartz, Stephen/0000-0001-6288-310X NR 6 TC 12 Z9 12 U1 3 U2 8 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 1 PY 1992 VL 256 IS 5057 BP 598 EP 599 DI 10.1126/science.256.5057.598-a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HR185 UT WOS:A1992HR18500003 PM 17843469 ER PT J AU GUSTAFSON, JR AF GUSTAFSON, JR TI EGGS-ACTLY SO SCIENCE LA English DT Letter RP GUSTAFSON, JR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 2 TC 0 Z9 0 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 1 PY 1992 VL 256 IS 5057 BP 600 EP 600 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HR185 UT WOS:A1992HR18500006 PM 1585168 ER PT J AU BATES, JK BRADLEY, JP TEETSOV, A BRADLEY, CR TENBRINK, MB AF BATES, JK BRADLEY, JP TEETSOV, A BRADLEY, CR TENBRINK, MB TI COLLOID FORMATION DURING WASTE FORM REACTION - IMPLICATIONS FOR NUCLEAR WASTE-DISPOSAL SO SCIENCE LA English DT Article AB Insoluble plutonium- and americium-bearing colloidal particles formed during simulated weathering of a high-level nuclear waste glass. Nearly 100 percent of the total plutonium and americium in test ground water was concentrated in these submicrometer particles. These results indicate that models of actinide mobility and repository integrity, which assume complete solubility of actinides in ground water, underestimate the potential for radionuclide release into the environment. A colloid-trapping mechanism may be necessary for a waste repository to meet long-term performance specifications. C1 MVA INC,NORCROSS,GA 30093. MCCRONE ASSOCIATES INC,WESTMONT,IL 60559. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP BATES, JK (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 24 TC 69 Z9 71 U1 0 U2 17 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 1 PY 1992 VL 256 IS 5057 BP 649 EP 651 DI 10.1126/science.256.5057.649 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HR185 UT WOS:A1992HR18500027 PM 17843487 ER PT J AU DUONG, H BEEMAN, M MCCLELLAND, RJ WOLFENSTINE, J AF DUONG, H BEEMAN, M MCCLELLAND, RJ WOLFENSTINE, J TI HIGH-TEMPERATURE DEFORMATION-BEHAVIOR OF KCL-RBCL SOLID-SOLUTION ALLOYS SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID CREEP-BEHAVIOR; SUBSTRUCTURE; MG C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP DUONG, H (reprint author), UNIV CALIF IRVINE,DEPT MECH & AEROSP ENGN,IRVINE,CA 92717, USA. NR 18 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAY 1 PY 1992 VL 26 IS 9 BP 1331 EP 1335 DI 10.1016/0956-716X(92)90644-T PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HP023 UT WOS:A1992HP02300005 ER PT J AU JANG, H SEIDMAN, DN MERKLE, KL AF JANG, H SEIDMAN, DN MERKLE, KL TI ATOMIC SCALE OBSERVATIONS OF THE CHEMICAL-COMPOSITION OF A METAL CERAMIC INTERFACE SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID INTERNAL INTERFACE; SEGREGATION C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NORTHWESTERN UNIV,MAT RES CTR,EVANSTON,IL 60208. RP JANG, H (reprint author), NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208, USA. RI Seidman, David/B-6697-2009 NR 29 TC 20 Z9 20 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAY 1 PY 1992 VL 26 IS 9 BP 1493 EP 1498 DI 10.1016/0956-716X(92)90672-2 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HP023 UT WOS:A1992HP02300033 ER PT J AU KAPER, HG KWONG, MK AF KAPER, HG KWONG, MK TI ON 2 CONJECTURES CONCERNING THE MULTIPLICITY OF SOLUTIONS OF A DIRICHLET PROBLEM SO SIAM JOURNAL ON MATHEMATICAL ANALYSIS LA English DT Article DE NONLINEAR BOUNDARY VALUE PROBLEM; MULTIPLICITY OF SOLUTIONS; VARIATION INDEX; TOPOLOGICAL DEGREE ID UNIQUENESS; RN AB It is shown that there exist two strictly convex functions, both denoted by f on (-infinity, infinity), the first satisfying the conditions f'(-infinity) < 1 and n2 < f'(infinity) < (n + 1)2 and the second satisfying the conditions (n - 1)2 < f'(-infinity) < n2 < f'(infinity) < (n + 1)2, such that the Dirichlet problem for the second-order nonlinear differential equation u" + f(u) = h(x) on [0, pi] has at least 2(n + 1) and five solutions, respectively. This settles in the negative two questions raised by Lazer and McKenna. RP KAPER, HG (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1410 J9 SIAM J MATH ANAL JI SIAM J. Math. Anal. PD MAY PY 1992 VL 23 IS 3 BP 571 EP 578 DI 10.1137/0523029 PG 8 WC Mathematics, Applied SC Mathematics GA HQ580 UT WOS:A1992HQ58000001 ER PT J AU CHEN, GQ AF CHEN, GQ TI GLOBAL-SOLUTIONS TO THE COMPRESSIBLE NAVIER-STOKES EQUATIONS FOR A REACTING MIXTURE SO SIAM JOURNAL ON MATHEMATICAL ANALYSIS LA English DT Article DE GLOBAL GENERALIZED SOLUTIONS; ASYMPTOTIC BEHAVIOR; EQUIVALENCE; COMBUSTION; DISCONTINUOUS ARRHENIUS FUNCTIONS; A PRIORI ESTIMATES; NAVIER-STOKES EQUATIONS ID DETONATION; MOTION; FLUIDS; GAS AB Existence theorems are established for global generalized solutions to the compressible Navier-Stokes equations for a reacting mixture with discontinuous Arrhenius functions, which describe dynamic combustion. Equivalence of the Navier-Stokes equations in the Euler coordinates and the Lagrange coordinates for the generalized solutions is verified. The asymptotic behavior of the generalized solutions with different boundary conditions is identified and proved. C1 ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. RP CHEN, GQ (reprint author), UNIV CHICAGO,DEPT MATH,CHICAGO,IL 60637, USA. RI Chen, Gui-Qiang G./A-1456-2012 OI Chen, Gui-Qiang G./0000-0001-5146-3839 NR 24 TC 54 Z9 58 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1410 J9 SIAM J MATH ANAL JI SIAM J. Math. Anal. PD MAY PY 1992 VL 23 IS 3 BP 609 EP 634 DI 10.1137/0523031 PG 26 WC Mathematics, Applied SC Mathematics GA HQ580 UT WOS:A1992HQ58000003 ER PT J AU WRIGHT, SJ AF WRIGHT, SJ TI STABLE PARALLEL ALGORITHMS FOR 2-POINT BOUNDARY-VALUE-PROBLEMS SO SIAM JOURNAL ON SCIENTIFIC AND STATISTICAL COMPUTING LA English DT Article DE PARALLEL ALGORITHMS; 2-POINT BOUNDARY VALUE PROBLEMS; ERROR ANALYSIS; STABILITY ID COLUMN ELIMINATION; LINEAR-SYSTEMS; ALTERNATE ROW; STABILITY; SOLVER AB Some of the most widely used algorithms for two-point boundary value ordinary differential equations, namely, finite-difference and collocation methods and standard multiple shooting, proceed by setting up and solving a structured system of linear equations. It is well known that the linear system can be set up efficiently in parallel; we show here that a structured orthogonal factorization technique can be used to solve this system, and hence the overall problem, in an efficient, parallel, and stable way. RP WRIGHT, SJ (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 21 TC 44 Z9 45 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0196-5204 J9 SIAM J SCI STAT COMP PD MAY PY 1992 VL 13 IS 3 BP 742 EP 764 DI 10.1137/0913044 PG 23 WC Mathematics, Applied SC Mathematics GA HP918 UT WOS:A1992HP91800008 ER PT J AU FASEL, JH PEYTONJONES, S HUDAK, P WADLER, P AF FASEL, JH PEYTONJONES, S HUDAK, P WADLER, P TI SIGPLAN NOTICES SPECIAL ISSUE ON THE FUNCTIONAL PROGRAMMING LANGUAGE HASKELL SO SIGPLAN NOTICES LA English DT Editorial Material C1 YALE UNIV,DEPT COMP SCI,NEW HAVEN,CT 06520. UNIV GLASGOW,DEPT COMP SCI,GLASGOW G12 8QQ,SCOTLAND. RP FASEL, JH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0362-1340 J9 SIGPLAN NOTICES JI Sigplan Not. PD MAY PY 1992 VL 27 IS 5 BP 1 EP 1 PG 1 WC Computer Science, Software Engineering SC Computer Science GA HR678 UT WOS:A1992HR67800001 ER PT J AU HUDAK, P FASEL, JH AF HUDAK, P FASEL, JH TI A GENTLE INTRODUCTION TO HASKELL SO SIGPLAN NOTICES LA English DT Article C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. RP HUDAK, P (reprint author), YALE UNIV,DEPT COMP SCI,NEW HAVEN,CT 06520, USA. NR 7 TC 11 Z9 11 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0362-1340 J9 SIGPLAN NOTICES JI Sigplan Not. PD MAY PY 1992 VL 27 IS 5 BP T1 EP T53 PG 53 WC Computer Science, Software Engineering SC Computer Science GA HR678 UT WOS:A1992HR67800002 ER PT J AU SOLHEIM, I PAYNE, TL CASTAIN, R AF SOLHEIM, I PAYNE, TL CASTAIN, R TI THE POTENTIAL IN USING BACKPROPAGATION NEURAL NETWORKS FOR FACIAL VERIFICATION SYSTEMS SO SIMULATION LA English DT Article AB A survey was conducted testing the aptitude of neural networks verify human faces. The motivation for such a study is the possibility of designing security systems. Pictures of 511 subjects were collected, The pictures captured both profiles and many natural expressions of the subject. Some of the subjects were wearing glasses, sunglasses or hats in some of the pictures. The images were compressed by a magnitude of 100, and converted into image vectors of 1400 pixels. The image vector were fed into a backpropagation neural network with one hidden layer and one output node. The networks were trained to yield an output that approached 1.0 for the target subject and 0.0 for the other subjects. Neural networks for 37 target subjects were trained using eight different training sets that consisted of different subsets of the data. The networks were then tested on the rest Of the data that consisted of 7,000 or more unseen pictures. Our results indicate that a false acceptance rate of less than 1% can be obtained, and a high verification rate can be obtained when certain restrictions are followed. RP SOLHEIM, I (reprint author), LOS ALAMOS NATL LAB,DIV SPACE SCI & TECHNOL,LOS ALAMOS,NM 87544, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD MAY PY 1992 VL 58 IS 5 BP 306 EP 310 PG 5 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA HX900 UT WOS:A1992HX90000003 ER PT J AU HACKER, BC AF HACKER, BC TI THE GEMINI PARAGLIDER - A FAILURE OF SCHEDULED INNOVATION, 1961-64 SO SOCIAL STUDIES OF SCIENCE LA English DT Article; Proceedings Paper CT SYMP ON FAILED INNOVATIONS, AT THE 18TH INTERNATIONAL CONGRESS OF HISTORY OF SCIENCE CY AUG, 1989 CL HAMBURG, GERMANY SP INT COMM HIST TECHNOL AB The paraglider was conceived during the 1950s as a lightweight hybrid of parachute and inflated wing that might allow astronauts to pilot spacecraft to airfield landings. From 1961 to 1964, the US National Aeronautics and Space Administration (NASA) sought to convert the idea into a practical landing system for the Gemini spacecraft. The spacecraft would carry the paraglider safely tucked away through most of a mission. Only after re-entering the atmosphere from orbit would the crew deploy the wing. Having now converted their spacecraft into a makeshift glider, they could fly to an airfield landing. How and why this ingenious scheme failed is the subject of this paper. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 112 TC 1 Z9 1 U1 0 U2 1 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON, ENGLAND EC2A 4PU SN 0306-3127 J9 SOC STUD SCI JI Soc. Stud. Sci. PD MAY PY 1992 VL 22 IS 2 BP 387 EP 406 DI 10.1177/030631292022002012 PG 20 WC History & Philosophy Of Science SC History & Philosophy of Science GA HX001 UT WOS:A1992HX00100011 ER PT J AU FAYER, MJ ROCKHOLD, ML CAMPBELL, MD AF FAYER, MJ ROCKHOLD, ML CAMPBELL, MD TI HYDROLOGIC MODELING OF PROTECTIVE BARRIERS - COMPARISON OF FIELD DATA AND SIMULATION RESULTS SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID SOIL; WATER AB Protective barriers, which consist of layers of silt loam over sand and gravel, have been proposed as covers for waste sites located in semiarid south-central Washington state. The ability of an uncalibrated model to predict water contents, water storage, and drainage in barriers was tested for durations as long as 1.5 yr. Eight nonvegetated lysimeters containing the barrier layering sequence have been monitored since November 1987. The lysimeters were subjected to one of three precipitation treatments: ambient, 2 x average, and breakthrough (i.e., until drainage occurred). Distributions of measured and simulated water contents with depth were similar, maximum differences ranged from 0.023 cm3/cm3 for the ambient treatment to 0.089 cm3/cm3 near the soil-sand interface for the breakthrough treatment. Simulated storage followed the trend in the measured values, although differences as much as 5 cm were observed at certain times. Generally, the model overpredicted evaporation in the winter and underpredicted it in the summer. Root-mean-square errors were 1.47 and 2.21 cm for the ambient and 2 x -average treatments, respectively. Sensitivity tests revealed that the hydraulic-conductivity function, snow cover, and potential evaporation were important to successful modeling of storage in a protective barrier. When the above parameters and processes were adjusted (though not optimized), the root-mean-square error for the 2 x -average treatment was reduced 63% to 0.81 cm. For the breakthrough treatment, simulated drainage was obtained only by using field-measured sorption and saturated-conductivity data. This result indicates that hysteresis is important to successful modeling of drainage through protective barriers. RP FAYER, MJ (reprint author), PACIFIC NW LAB, DEPT GEOSCI, POB 999, RICHLAND, WA 99352 USA. NR 25 TC 58 Z9 59 U1 0 U2 1 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAY-JUN PY 1992 VL 56 IS 3 BP 690 EP 700 PG 11 WC Soil Science SC Agriculture GA JD368 UT WOS:A1992JD36800004 ER PT J AU SMITH, SC AINSWORTH, CC TRAINA, SJ HICKS, RJ AF SMITH, SC AINSWORTH, CC TRAINA, SJ HICKS, RJ TI EFFECT OF SORPTION ON THE BIODEGRADATION OF QUINOLINE SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID MICROBIAL-DEGRADATION; CLAY PARTICLES; ADSORPTION; WATER; SOIL; MONTMORILLONITE; DESORPTION; SEDIMENTS; EXCHANGE; SYSTEMS AB Quinoline is an N-containing heterocyclic contaminant associated with creosote wastes and may be biologically degraded under aerobic and anaerobic conditions. Quinoline-degrading bacteria were utilized to investigate the rate of quinoline desorption from smectite clay at low surface concentrations and its subsequent mineralization. Fluorescence spectroscopy and C-14-quinoline mineralization techniques were used to compare the observed desorption rates to mineralization rates. Microbial utilization was desorption-rate limiting. Desorption and microbial utilization may be modeled as pseudo-first-order reactions whose first-order rate constant (k(obs)) is independent of surface concentration. The difference between quinoline disappearance from solution and from the day surface as observed by fluorescence spectroscopy was comparable to the difference between microbial utilization of the solution and the surface-bound species. The utilization of quinoline from solution was about 30 times more rapid than surface-bound quinoline. The surface-bound species appeared to be protected from microbial attack and, hence, desorption was required prior to utilization. The desorption process is suggested to be a chemical-reaction-controlled process rather than film diffusion controlled, as is typically suggested for an exchange process. The biotransformation of quinoline to 2-hydroxyquinoline, observed in solution by fluorescence spectroscopy, was about five to eight times faster than the subsequent disappearance of 2-hydroxyquinoline. When quinoline was sorbed, however, no 2-hydroxyquinoline was observed in solution or on the surface of the clay. It is suggested that quinoline may be transformed to 2-hydroxyquinoline at the cell surface and that 2-hydroxyquinoline is the species that is transported into the cell prior to further degradation. C1 OHIO STATE UNIV,DEPT AGRON,COLUMBUS,OH 43210. GROUNDWATER TECHNOL INC,CONCORD,CA 94520. RP SMITH, SC (reprint author), ENVIRONM SCI DEPT,PACIFIC NW LAB,MSIN K3-61,POB 999,RICHLAND,WA 99352, USA. NR 41 TC 62 Z9 67 U1 2 U2 6 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAY-JUN PY 1992 VL 56 IS 3 BP 737 EP 746 PG 10 WC Soil Science SC Agriculture GA JD368 UT WOS:A1992JD36800011 ER PT J AU FAULQUES, E RUSSO, RE AF FAULQUES, E RUSSO, RE TI RAMAN-SPECTRA OF IODIDE SPECIES IN INTERCALATED IBI2SR2CACU2O8+DELTA SO SOLID STATE COMMUNICATIONS LA English DT Article ID SUPERCONDUCTORS; SPECTROSCOPY; CRYSTALS; MODES AB We report Raman spectra of pristine Bi2Sr2CaCu2O8+delta and intercalated stage-1 IBi2Sr2CaCu2O8+delta single crystals. Low frequency spectra of the intercalated crystal taken at room and liquid nitrogen temperatures with the 488 nm Ar+ excitation line exhibit a strong band at 105 cm-1 and weaker bands at almost-equal-to 73 and almost-equal-to 150 cm-1. The results are confirmed by using the 647 nm Kr+ excitation line. These bands characterize the fundamental vibrations of I3- molecular anions embedded in the lattice. Drastic change of the micro-Raman scattering in the 200-700 cm-1 region is observed between pristine and iodinated crystals. A factor group analysis of stage-1 IBi2Sr2CaCu2O8+delta is presented based on possible structures and predicts that iodine vibrations can be Raman active in a non-centrosymmetric lattice. C1 LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720. NR 29 TC 27 Z9 27 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAY PY 1992 VL 82 IS 7 BP 531 EP 535 DI 10.1016/0038-1098(92)90226-Y PG 5 WC Physics, Condensed Matter SC Physics GA HY237 UT WOS:A1992HY23700010 ER PT J AU BATES, JL CHICK, LA WEBER, WJ AF BATES, JL CHICK, LA WEBER, WJ TI SYNTHESIS, AIR SINTERING AND PROPERTIES OF LANTHANUM AND YTTRIUM CHROMITES AND MANGANITES SO SOLID STATE IONICS LA English DT Article; Proceedings Paper CT WORKSHOP ON CERAMIC CONDUCTORS FOR SOLID STATE ELECTROCHEMICAL DEVICES CY MAY 12-14, 1991 CL SNOWBIRD, UT SP ELECT POWER RES INST, GAS RES INST ID POWDERS AB A new combustion process, the Glycine-Nitrate Process (GNP), is used for synthesizing ultra-fine, single- or multi-phase electrically conducting oxide powders. The resulting powders are crystalline, homogeneous, softly agglomerated, and vary in size between 1 and 100 nm depending upon composition and synthesis parameters, The process is simple, rapid, low-cost and environmentally compatible. GNP synthesized yttrium and lanthanum chromite powders can be air-sintered to high density below 1550-degrees-C. The air-sintering mechanisms are functions of alkaline-earth concentration, cation ratio, vapor loss and liquid-phase formation. Sintered densities increase with increasing alkaline-earth substitution and with increasing (La + Sr)/Cr and (Y + Ca)/Cr ratios. Large changes in air sinterability can occur with small changes in these cation ratios. Vaporization of Cr appears to be a major influence in La1-xSrxCrO3 air-sintering. Liquid-phase sintering appears to be a major factor in the sintering of Y1-xCaxCrO3. The electrical conductivity and thermal expansion also increase with increasing alkaline-earth substitution for the lanthanum or yttrium chromites and manganites. In addition, the electrical, thermal and structural properties of these perovskite materials are also influenced by the synthesis and processing conditions as well as by thermal cycling and heat treatment in air. RP BATES, JL (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 13 TC 27 Z9 30 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD MAY PY 1992 VL 52 IS 1-3 BP 235 EP 242 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA JD256 UT WOS:A1992JD25600027 ER PT J AU KUEPER, TW VISCO, SJ DEJONGHE, LC AF KUEPER, TW VISCO, SJ DEJONGHE, LC TI THIN-FILM CERAMIC ELECTROLYTES DEPOSITED ON POROUS AND NONPOROUS SUBSTRATES BY SOL-GEL TECHNIQUES SO SOLID STATE IONICS LA English DT Article; Proceedings Paper CT WORKSHOP ON CERAMIC CONDUCTORS FOR SOLID STATE ELECTROCHEMICAL DEVICES CY MAY 12-14, 1991 CL SNOWBIRD, UT SP ELECT POWER RES INST, GAS RES INST AB Successful deposition of ultra-thin ceramic membranes by the sol-gel process could lead to greatly improved electrolyte devices. The parameters of the sol-gel technique which affect film cracking and continuity have been investigated, and the effect of substrate conditions and substrate porosity have been determined. Crack-free yttria-stabilized zirconia films having thickness of approximately 0.2 to 0.5-mu-m have been deposited on continuous quartz substrates. Preliminary results have also indicated that continuous sub-micron electrolyte films can be deposited on porous substrates. RP KUEPER, TW (reprint author), LAWRENCE BERKELEY LAB,DIV MAT SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 9 TC 55 Z9 56 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD MAY PY 1992 VL 52 IS 1-3 BP 251 EP 259 DI 10.1016/0167-2738(92)90113-4 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA JD256 UT WOS:A1992JD25600030 ER PT J AU ELLISON, J PASSAGE, M YU, LC YEN, P MOHANDAS, TK SHAPIRO, L AF ELLISON, J PASSAGE, M YU, LC YEN, P MOHANDAS, TK SHAPIRO, L TI DIRECTED ISOLATION OF HUMAN GENES THAT ESCAPE X-INACTIVATION SO SOMATIC CELL AND MOLECULAR GENETICS LA English DT Article ID Y-CHROMOSOME; PSEUDOAUTOSOMAL REGION; LINKED GENES; CELL HYBRIDS; LOCUS; ZFX; EXPRESSION; PROTEIN; CLONING; MOUSE AB Existing methodologies have been combined to produce a directed approach to the isolation of human genes that escape X inactivation. A mouse-human somatic cell hybrid line was established that has an inactive X as its only human chromosome, and nuclear RNA from this cell line was used to construct a cDNA library. Transcribed human sequences were isolated by screening the library with labeled human DNA. The corresponding genomic sequences were isolated in phage or cosmid clones, and exons were identified by detection of transcripts on northern blots. By these means three human loci have been identified that contain genes expressed from an inactive X chromosome. Fluorescence in situ hybridization has been used to map these genes to Xp21.1-22.1, Xp22.1-22.2, and terminal Xp/Yp. One of the three genes (XE45) corresponds to the ZFX gene, while the other two genes (XE7 and XE59) represent novel cloned sequences. Physical and genetic evidence indicate that XE7 is a newly identified pseudoautosomal gene. C1 UNIV CALIF LOS ANGELES,SCH MED,HARBOR MED CTR,HOWARD HUGHES MED INST,TORRANCE,CA 90509. UNIV CALIF LOS ANGELES,SCH MED,HARBOR MED CTR,DEPT PEDIAT,TORRANCE,CA 90509. UNIV CALIF LOS ANGELES,SCH MED,HARBOR MED CTR,DEPT BIOL CHEM,TORRANCE,CA 90509. LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. FU NICHD NIH HHS [HD12178, HD15193] NR 51 TC 37 Z9 38 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0740-7750 J9 SOMAT CELL MOLEC GEN JI Somat.Cell Mol.Genet. PD MAY PY 1992 VL 18 IS 3 BP 259 EP 268 DI 10.1007/BF01233862 PG 10 WC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity GA JH561 UT WOS:A1992JH56100006 PM 1496421 ER PT J AU WIEDNER, U AMSLER, C AUGUSTIN, I BAKER, CA BARNETT, BM BATTY, CJ BECKMANN, R BEUCHERT, K BIRIEN, P BISTIRLICH, J BLUM, P BOSSINGHAM, R BOSSY, H BRAUNE, K BUGG, DV BURCHELL, M CASE, T CROWE, KM DUNNWEBER, W ENGELHARDT, D FAESSLER, M FELIX, C FOLGER, G HADDOCK, R HEINSIUS, FH HESSEY, NP LLINGER, P JAMNIK, D KALINOWSKY, H KAMMLE, B KIEL, T KLEMPT, E KOCH, H KONIGSMANN, K KUNZE, M LANDAU, R MATTHAY, H MERKEL, M MERLO, JP MEYER, CA MEYERBERKHOUT, U MONTANET, L NOBEL, A PETERS, K PINTER, G RAVNDAL, S SANJARI, A SCHAFER, E SCHMID, B STRASSBURGER, C STROHBUSCH, U SUFFERT, M URNER, D WALTHER, D WIEDNER, U WINTER, N ZOLL, J ZUPANCIC, C AF WIEDNER, U AMSLER, C AUGUSTIN, I BAKER, CA BARNETT, BM BATTY, CJ BECKMANN, R BEUCHERT, K BIRIEN, P BISTIRLICH, J BLUM, P BOSSINGHAM, R BOSSY, H BRAUNE, K BUGG, DV BURCHELL, M CASE, T CROWE, KM DUNNWEBER, W ENGELHARDT, D FAESSLER, M FELIX, C FOLGER, G HADDOCK, R HEINSIUS, FH HESSEY, NP LLINGER, P JAMNIK, D KALINOWSKY, H KAMMLE, B KIEL, T KLEMPT, E KOCH, H KONIGSMANN, K KUNZE, M LANDAU, R MATTHAY, H MERKEL, M MERLO, JP MEYER, CA MEYERBERKHOUT, U MONTANET, L NOBEL, A PETERS, K PINTER, G RAVNDAL, S SANJARI, A SCHAFER, E SCHMID, B STRASSBURGER, C STROHBUSCH, U SUFFERT, M URNER, D WALTHER, D WIEDNER, U WINTER, N ZOLL, J ZUPANCIC, C TI RECENT RESULTS FROM THE CRYSTAL BARREL EXPERIMENT SO SOVIET JOURNAL OF NUCLEAR PHYSICS-USSR LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON INTERACTIONS OF ANTINUCLEONS WITH NUCLEONS AND NUCLEI ( NAN-91 ) CY JUL 08-11, 1991 CL INST THEORET EXPT PHYS, MOSCOW, USSR SP ACAD SCI, USSR, MINIST ATOM POWER & IND, USSR HO INST THEORET EXPT PHYS ID ANNIHILATIONS; SCATTERING; PROTON AB The Crystal Barrel experiment has been constructed and installed at the Low Energy Antiproton Ring (LEAR) at CERN. It has been fully operational since late 1989. In this talk, recent results of meson spectroscopy in ppBAR annihilations are presented. The main emphasis is on all-neutral annihilations, the study of the strange quark content of the proton, and the investigation of the decay mode of eta-particles. A 2++ resonance decaying into pi-degrees pi-degrees at a mass of 1515 +/- 10 MeV, with a width of 120 +/- 10 MeV, has been seen in a 3-pi-degrees final state. C1 CERN,CH-1211 GENEVA 23,SWITZERLAND. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RUHR UNIV BOCHUM,W-4630 BOCHUM,GERMANY. ACAD SCI BUDAPEST,BUDAPEST,HUNGARY. UNIV KARLSRUHE,W-7500 KARLSRUHE,GERMANY. QUEEN MARY & WESTFIELD COLL,LONDON,ENGLAND. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV MAINZ,W-6500 MAINZ,GERMANY. UNIV MUNICH,W-8000 MUNICH 2,GERMANY. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. CTR RECH NUCL,F-67037 STRASBOURG,FRANCE. UNIV ZURICH,CH-8006 ZURICH,SWITZERLAND. RP WIEDNER, U (reprint author), UNIV HAMBURG,W-2000 HAMBURG 13,GERMANY. NR 17 TC 2 Z9 2 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0038-5506 J9 SOV J NUCL PHYS+ PD MAY PY 1992 VL 55 IS 5 BP 767 EP 777 PG 11 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA HZ539 UT WOS:A1992HZ53900024 ER PT J AU JOHNSON, SG FEAREY, BL MILLER, CM NOGAR, NS AF JOHNSON, SG FEAREY, BL MILLER, CM NOGAR, NS TI RESONANCE IONIZATION MASS-SPECTROMETRY OF THORIUM - DETERMINATION OF THE AUTOIONIZATION LEVEL STRUCTURE AND A RE-DETERMINATION OF THE IONIZATION-POTENTIAL SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article ID LASER SPECTROSCOPY; RYDBERG STATES; TRACE ANALYSIS; ATOMS; TH; SYSTEMATICS; FIELDS; PB AB We report on the use of resonance ionization mass spectrometry (RIMS) for the analysis of thorium isotopes. The U-238/Th-230 decay pair is useful for the dating of geologic samples in the less-than-or-equal-to 350000 year range, and details are needed on the resonance ionization spectrum of thorium in order to most efficiently effect ionization. This report describes the use of a two-color, two photon ionization process for thorium near the ionization threshold. A large number of autoionizing states are observed, a new value for the ionization potential, 50 890 +/- 20 cm-1 (6.310 +/- 0.002 eV), is reported, and electric field effects are described. C1 LOS ALAMOS NATL LAB,DIV CHEM & LASER SCI,MS J565,LOS ALAMOS,NM 87545. ARGONNE W NATL LAB,ANALYT CHEM GRP,IDAHO FALLS,ID 83703. LOS ALAMOS NATL LAB,DIV ISOTOPE & NUCL CHEM,LOS ALAMOS,NM 87545. NR 46 TC 18 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD MAY PY 1992 VL 47 IS 5 BP 633 EP 643 DI 10.1016/0584-8547(92)80058-O PG 11 WC Spectroscopy SC Spectroscopy GA HW856 UT WOS:A1992HW85600005 ER PT J AU CHU, CY ROUTBORT, JL CHEN, N BIONDO, AC KUPPERMAN, DS GORETTA, KC AF CHU, CY ROUTBORT, JL CHEN, N BIONDO, AC KUPPERMAN, DS GORETTA, KC TI MECHANICAL-PROPERTIES AND TEXTURE OF DENSE POLYCRYSTALLINE BI2SR2CACU2OX SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article AB Very dense Bi2Sr2CaCu2Ox bulk specimens were fabricated by hot isostatic pressing or sinter forging. The specimens exhibited textures in which the c-axes were aligned preferentially perpendicular to the top and bottom faces. Fracture toughness was found to be dependent on orientation, with the values ranging from 2.7 to 3.9 MPa m0.5. The average Vickers hardness for the specimens was almost-equal-to 700 MPa. Elastic anisotropy determined by velocity of sound measurements was consistent with textures determined by x-ray diffraction. C1 ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439. RP CHU, CY (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 27 TC 40 Z9 40 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD MAY PY 1992 VL 5 IS 5 BP 306 EP 312 DI 10.1088/0953-2048/5/5/006 PG 7 WC Physics, Applied; Physics, Condensed Matter SC Physics GA HX148 UT WOS:A1992HX14800006 ER PT J AU BAER, DR HUBBARD, CW GORDON, RL AF BAER, DR HUBBARD, CW GORDON, RL TI INFLUENCE OF CU, AG, IR AND PT ON THE WORK FUNCTION AND NEAR-SURFACE ELECTRON-DENSITY OF RE MASS-SPECTROMETER FILAMENTS SO SURFACE AND INTERFACE ANALYSIS LA English DT Article ID SINGLE-CRYSTAL SURFACES; FORMED RE-1-PERCENT PD; PHOTOELECTRON-SPECTROSCOPY; LEVEL SHIFTS; ADSORPTION; UPS; AU; CONDENSATION AB The influence of metal overlayers on the properties of polycrystalline Re mass spectrometer filaments has been examined using contact potential difference (CPD) measurements of the work function, x-ray photoelectron spectroscopy (XPS) measurements of overlayer binding energy (BE) and ultraviolet photoelectron spectroscopy (UPS) measurements of electron energy distribution curves (EDCs). Work function data for Cu-Re, Ag-Re and Ir-Re are compared to earlier results for Au-Re, Pd-Re and Pt-Re as part of the effort to understand the influence of surface additions to the work functions of ionization sources. The changes in work function owing to the addition of a metal overlayer do not always follow predictions of bulk electron transfer, such as the Miedema electronegativity. However, the observed changes in work function are consistent with a simple initial-state understanding of the XPS core-level data involving charge flow toward and away from the surface. The XPS binding energy shifts are consistent with shifts observed in the valence bands for Cu and Ag on Re. RP BAER, DR (reprint author), PACIFIC NW LAB, MS K2-57,BOX 999, RICHLAND, WA 99352 USA. RI Baer, Donald/J-6191-2013 OI Baer, Donald/0000-0003-0875-5961 NR 33 TC 4 Z9 4 U1 0 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD MAY PY 1992 VL 18 IS 5 BP 306 EP 314 DI 10.1002/sia.740180504 PG 9 WC Chemistry, Physical SC Chemistry GA HW470 UT WOS:A1992HW47000003 ER PT J AU VURENS, GH MAURICE, V SALMERON, M SOMORJAI, GA AF VURENS, GH MAURICE, V SALMERON, M SOMORJAI, GA TI GROWTH, STRUCTURE AND CHEMICAL-PROPERTIES OF FEO OVERLAYERS ON PT(100) AND PT(111) SO SURFACE SCIENCE LA English DT Article ID METAL SUPPORT INTERACTION; OXIDE-FILMS; THIN-FILMS; OXIDATION; CO; ADSORPTION; IRON; CHEMISORPTION; SURFACES; TITANIA AB Iron oxide was deposited on Pt(111) and Pt(100). In both cases the growth mode appears to be layer-by-layer for the first few layers, as indicated by Auger and ion scattering spectroscopies. Ordered structures were formed after annealing as indicated by LEED with (10 x 10) and c(2 x 10) expitaxial relationships, respectively. The Fe/Pt atomic ratio was the same for both substrates and the stoichiometry was approximately Fe:O = 1:1, with the (100) substrate containing less O relative to Fe than the (111) substrate. The oxidation state of Fe is 2 according to XPS. A model is proposed for both overlayers consisting of an FeO(111) bilayer of Fe2 and O2-. The chemical properties of these two oxide monolayers were found to be similar in regard to H2O adsorption, but very different toward CO chemisorption. Their stability towards alkali metal deposition was found to be different also. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV PARIS 06,ECOLE NATL SUPER CHIM PARIS,PHYSICOCHIM SURFACES LAB,UA 425,F-75231 PARIS 05,FRANCE. RP VURENS, GH (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Maurice, Vincent/F-9196-2015 OI Maurice, Vincent/0000-0001-5222-9972 NR 22 TC 77 Z9 77 U1 5 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 1 PY 1992 VL 268 IS 1-3 BP 170 EP 178 DI 10.1016/0039-6028(92)90960-E PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HR728 UT WOS:A1992HR72800032 ER PT J AU ZHOU, Y JENNINGS, G CAMPUZANO, JC AGRAWAL, VK TRENARY, M AF ZHOU, Y JENNINGS, G CAMPUZANO, JC AGRAWAL, VK TRENARY, M TI A MONTE-CARLO SIMULATION OF THE OVERLAYER STRUCTURE OF PF3 ON PT(111) SO SURFACE SCIENCE LA English DT Article ID VIBRATIONAL PHASE RELAXATION; ORDER-DISORDER TRANSITION; SURFACES; CO; NI(111); SPECTRA; MOTION AB Infrared reflection-absorption spectroscopy of the P-F symmetric stretch region of PF3 chemisorbed on Pt(111) shows two absorption bands whose relative intensities change as a function of temperature and coverage. These changes in the infrared spectra are attributed to changes in the PF3 overlayer structure. Here we have carried out Monte Carlo simulations of this system based on the Ising model. We find that when we consider the interaction energy between a molecule and up its third-nearest neighbors, a constrained lattice gas model reproduces the experimental infrared spectroscopy results. One of the two bands arises from those molecules which condense into compact ordered clusters, and the other band from the rest of the molecules. Because the exact relationship between the P-F stretch frequency and the adsorbate environment is not known, the contribution of each molecule to a particular band is not straightforward and a statistical method for assigning molecules to each infrared band is developed. Though the model is very simple, the simulation results are in quantitative agreement with the experimental data. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV ILLINOIS,DEPT CHEM MC111,CHICAGO,IL 60680. RP ZHOU, Y (reprint author), UNIV ILLINOIS,DEPT PHYS MC273,CHICAGO,IL 60680, USA. RI Campuzano, Juan Carlos/G-4358-2012 NR 33 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 1 PY 1992 VL 268 IS 1-3 BP 378 EP 386 DI 10.1016/0039-6028(92)90977-E PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HR728 UT WOS:A1992HR72800049 ER PT J AU SHUSTOROVICH, E BELL, AT AF SHUSTOROVICH, E BELL, AT TI OXYGEN-ASSISTED CLEAVAGE OF O-H, N-H, AND C-H BONDS ON TRANSITION-METAL SURFACES - BOND-ORDER-CONSERVATION MORSE-POTENTIAL ANALYSIS SO SURFACE SCIENCE LA English DT Article ID ELECTRON-ENERGY LOSS; FORMIC-ACID DECOMPOSITION; COPPER(110) CATALYST; SELECTIVE OXIDATION; PREADSORBED OXYGEN; REACTION-KINETICS; LOSS SPECTROSCOPY; AU(110) SURFACE; ATOMIC OXYGEN; ADSORPTION AB The energetics of O-H, N-H, and C-H bond cleavage on clean and (low-coverage) oxygen-preadsorbed metal surfaces has been analyzed using the BOC-MP (bond-order-conservation-Morse-potential) method. The molecules in question included CH3OH, HCOOH, and NH3, adsorbed on Ag(111), Cu(111), Ni(111), W(110), and CH4 adsorbed on Ni(111) and Ni(100). The reaction enthalpies, DELTA-H, and the activation energies, DELTA-E*, have been calculated for a variety of elementary steps corresponding to the direct and oxygen-assisted cleavage of X-H bonds (X = O, N, C). For the O-H and N-H bonds, the presence of preadsorbed oxygen always decreases the values of DELTA-H and DELTA-E* for Ag(111), but increases them for W(110). For Cu(111) and Ni(111), the changes in DELTA-H and DELTA-E* are less uniform but, as a whole, Cu(111) resembles Ag(111), whereas Ni(111) is closer to W(110). In other words, the effect of preadsorbed oxygen at low coverages on the O-H and N-H bond cleavage is projected to be reversed along the series Ag, Cu, Ni, W, from facilitating X-H bond cleavage on the least active metals such as Ag (or Au), to inhibiting this process on the most active metals, such as W (or Mo). The presence of preadsorbed oxygen on Ni(111) and Ni(100) is detrimental to the cleavage of C-H bonds in CH4. The BOC-MP model projections are in broad agreement with experimental observation. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. RP SHUSTOROVICH, E (reprint author), EASTMAN KODAK CO,CORP RES LABS,ROCHESTER,NY 14650, USA. OI Bell, Alexis/0000-0002-5738-4645 NR 46 TC 54 Z9 55 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 MAY 1 PY 1992 VL 268 IS 1-3 BP 397 EP 405 DI 10.1016/0039-6028(92)90979-G PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HR728 UT WOS:A1992HR72800051 ER PT J AU BOHNEN, KP CHAN, CT HO, KM AF BOHNEN, KP CHAN, CT HO, KM TI ON THE BILAYER GROWTH MODE OF AU ON AG(110) SO SURFACE SCIENCE LA English DT Letter ID NORM-CONSERVING PSEUDOPOTENTIALS; SCATTERING AB The energetics of the growth of Au on the Ag(110) surface is investigated using first principles total energy calculations. Our results indicate that a recently observed bilayer growth mode is actually energetically unfavorable for this system. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP BOHNEN, KP (reprint author), KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH,INST NUKL FESTKORPERPHYS,W-7500 KARLSRUHE 1,GERMANY. NR 18 TC 11 Z9 11 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 MAY 1 PY 1992 VL 268 IS 1-3 BP L284 EP L286 DI 10.1016/0039-6028(92)90936-Z PG 3 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HR728 UT WOS:A1992HR72800008 ER PT J AU SCHLYER, DJ VOLKOW, ND FOWLER, JS WOLF, AP SHIUE, CY DEWEY, SL BENDRIEM, B LOGAN, J RAULLI, R HITZEMANN, R BRODIE, J ALAVI, AA MACGREGOR, RR AF SCHLYER, DJ VOLKOW, ND FOWLER, JS WOLF, AP SHIUE, CY DEWEY, SL BENDRIEM, B LOGAN, J RAULLI, R HITZEMANN, R BRODIE, J ALAVI, AA MACGREGOR, RR TI REGIONAL DISTRIBUTION AND KINETICS OF HALOPERIDOL BINDING IN HUMAN BRAIN - A PET STUDY WITH [F-18] HALOPERIDOL SO SYNAPSE LA English DT Article DE DOPAMINE RECEPTORS; NEUROLEPTICS; SIGMA-RECEPTORS; SCHIZOPHRENIA ID POSITRON EMISSION TOMOGRAPHY; F-18 N-METHYLSPIROPERIDOL; ANTIPSYCHOTIC-DRUGS; DOPAMINE-RECEPTORS; SCHIZOPHRENIC-PATIENTS; NEUROLEPTIC DRUGS; OPIATE RECEPTORS; SIGMA-RECEPTORS; RAT-BRAIN; INVIVO AB The regional distribution and the kinetics of haloperidol uptake in human brain were examined using [F-18]haloperidol and PET in 9 controls and 5 schizophrenics while on haloperidol medication and after haloperidol washout. The regional distribution of [F-18]N-methylspiroperidol, a tracer for D2 receptors, was measured in 1 normal subject for comparison. The uptake of [F-18]haloperidol in the whole brain in normals was high (6.6% of the injected dose at 2 hr), and regional distribution was much more extensive than could be accounted for by the distribution of dopamine D2 receptors. In normals, the cerebellum, basal ganglia, and thalamus showed a greater concentration than the cortex, and there was minimal clearance of F-18 from the brain during the 10-hr period of the study. Medicated schizophrenics showed a total brain uptake of 4.0% and had a significant clearance of [F-18]haloperidol from brain and a higher concentration of [F-18]haloperidol in plasma. After withdrawal from medication, [F-18]haloperidol clearance from brain became slower than while on medication. These results are discussed in terms of the pharmacokinetics of haloperidol in the human brain and its binding to dopamine D2 receptors and to sigma receptors. C1 BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. SUNY STONY BROOK,STONY BROOK,NY 11794. VET ADM MED CTR,PSYCHIAT SERV,NORTHPORT,NY 11768. NYU MED CTR,NEW YORK,NY 10016. UNIV PENN,PHILADELPHIA,PA 19104. RP SCHLYER, DJ (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. FU NINDS NIH HHS [NS-15638] NR 39 TC 27 Z9 27 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-4476 J9 SYNAPSE JI Synapse PD MAY PY 1992 VL 11 IS 1 BP 10 EP 19 DI 10.1002/syn.890110103 PG 10 WC Neurosciences SC Neurosciences & Neurology GA HQ757 UT WOS:A1992HQ75700002 PM 1604422 ER PT J AU HATTEMERFREY, HA TRAVIS, C AF HATTEMERFREY, HA TRAVIS, C TI HUMAN EXPOSURE TO BENZO(A)PYRENE - SOME MORE OF THE STORY SO TOXICOLOGY AND INDUSTRIAL HEALTH LA English DT Letter C1 OAK RIDGE NATL LAB,CTR RISK MANAGEMENT,OAK RIDGE,TN 37831. RP HATTEMERFREY, HA (reprint author), DAMES & MOORE INC,1100 SANDERS RD,KNOXVILLE,TN 37932, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU PRINCETON SCIENTIFIC PUBL INC PI PRINCETON PA PO BOX 2155, PRINCETON, NJ 08543 SN 0748-2337 J9 TOXICOL IND HEALTH JI Toxicol. Ind. Health PD MAY-JUN PY 1992 VL 8 IS 3 BP 217 EP 219 PG 3 WC Public, Environmental & Occupational Health; Toxicology SC Public, Environmental & Occupational Health; Toxicology GA JF748 UT WOS:A1992JF74800008 ER PT J AU EVANS, RW AF EVANS, RW TI PUBLIC AND PRIVATE INSURER DESIGNATION OF TRANSPLANTATION PROGRAMS SO TRANSPLANTATION LA English DT Article ID CARDIAC TRANSPLANTATION; COST-EFFECTIVENESS; HOSPITAL VOLUME; SURGEON VOLUME; HEART-SURGERY; MORTALITY; CENTERS; THERAPY; MATTERS; FUTURE AB In an effort to assure quality and contain costs, several major private health insurers now restrict payment of transplantation procedures to designated programs, often referred to as centers of excellence. These insurers underwrite coverage for over 100 million people. Few transplantation programs meet the criteria set forth by insurers, thus raising concerns about patient access to care. The criteria being used by five private insurers and Medicare were obtained and reviewed. Insurers now designate kidney, heart, liver, heart-lung, pancreas, and bone marrow transplant programs based upon total annual transplant volume as well as one- and two-year patient and graft survival rates. Transplant center criteria vary according to procedure and type of recipient (i.e., pediatric vs. adult). Most insurers require hospitals to perform a minimum of at least 6, and up to 50 procedures annually. Expected one-year patient survival rates may exceed 90% and are often higher than 80%, although standards are usually lower for heart-lung and bone marrow transplantation. In addition, if centers meet the minimum volume and outcome criteria, insurers expect transplant centers to discount per procedure charges by as much as 25%. Patients are often offered incentives to use designated centers with insurers frequently paying travel costs and reducing or waiving copayment amounts. The designation of transplant programs by third-party payers has merit, although program volume requirements may have less validity than individual transplant surgeon and physician experience. Other problems are also apparent. For example, discount pricing is suspect, given the lack of data on actual transplant procedure costs. Also, some insurers intend to regionalize transplant programs, thus unnecessarily limiting patient access to care. Alternatively, the concentration of transplant activity at a smaller number of centers may enhance research opportunities. Nonetheless, transplant professionals, hospital administrators, and patient advocates remain wary of insurer objectives. There is concern that the designation of centers is simply another method by which insurers can avoid paying for transplants. RP BATTELLE SEATTLE RES CTR, HLTH & POPULAT RES CTR, SEATTLE, WA 98105 USA. NR 54 TC 15 Z9 15 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA TWO COMMERCE SQ, 2001 MARKET ST, PHILADELPHIA, PA 19103 USA SN 0041-1337 EI 1534-6080 J9 TRANSPLANTATION JI Transplantation PD MAY PY 1992 VL 53 IS 5 BP 1041 EP 1046 DI 10.1097/00007890-199205000-00014 PG 6 WC Immunology; Surgery; Transplantation SC Immunology; Surgery; Transplantation GA HU814 UT WOS:A1992HU81400014 PM 1585467 ER PT J AU WURZ, P LYKKE, KR PELLIN, MJ GRUEN, DM PARKER, DH AF WURZ, P LYKKE, KR PELLIN, MJ GRUEN, DM PARKER, DH TI CHARACTERIZATION OF FULLERENES BY LASER-BASED MASS-SPECTROMETRY SO VACUUM LA English DT Article; Proceedings Paper CT 3RD EUROPEAN VACUUM CONF ( EVC-3 ) / 5TH AUSTRIAN - HUNGARIAN - YUGOSLAV JOINT VACUUM CONF CY SEP 23-27, 1991 CL TECH UNIV WIEN, VIENNA, AUSTRIA HO TECH UNIV WIEN ID CARBON; C-60; BUCKMINSTERFULLERENE; FORM; C60 AB Mass characterization of C60 related high-mass carbon clusters, called fullerenes, and their compounds is of increasing interest as the unique properties of these materials become known. We are using laser desorption time-of-flight mass spectrometers to investigate direct emission of positive and negative ions and also neutral desorption. We show results on the laser desorption process, namely, desorption thresholds for positive ion, negative ion and neutral desorption and velocity distributions of desorbed neutral particles. Furthermore, post-ionization with the wavelengths 118, 212.8, 266, 355, and 532 nm is investigated. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. UNIV CALIF IRVINE,INST SURFACE & INTERFACE SCI,IRVINE,CA 92627. RP WURZ, P (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 26 TC 16 Z9 16 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0042-207X J9 VACUUM JI Vacuum PD MAY-JUL PY 1992 VL 43 IS 5-7 BP 381 EP 385 DI 10.1016/0042-207X(92)90041-T PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA JA721 UT WOS:A1992JA72100005 ER PT J AU EDWARDS, NT EDWARDS, GL KELLY, JM TAYLOR, GE AF EDWARDS, NT EDWARDS, GL KELLY, JM TAYLOR, GE TI 3-YEAR GROWTH-RESPONSES OF PINUS-TAEDA L TO SIMULATED RAIN CHEMISTRY, SOIL MAGNESIUM STATUS, AND OZONE SO WATER AIR AND SOIL POLLUTION LA English DT Article ID NET PHOTOSYNTHESIS; LOBLOLLY-PINE; ACIDIC RAIN; FIELD; ALLOCATION; AMBIENT; FORESTS; TREE AB Height, diameter, and biomass were measured for loblolly pine (Pinus taeda L) seedlings grown in soil containing 15 or 35-mu-g Mg g-1 and exposed from May to October in 1987, 1988, and 1989 to three O3 concentrations (sub-ambient, ambient, or twice-ambient) and to rain pH levels of 3.8 or 5.2. Reduction in biomass accumulation in seedlings exposed to twice-ambient O3 vs sub-ambient O3 was 14% (P = 0.03) in 1987, 11.4% (P = 0.002) by 1988, and 8% (P = 0.15) by 1989. The greatest height growth occurred in seedlings exposed to twice-ambient O3, and the greatest stem diameter growth occurred in seedlings exposed to sub-ambient O3. A comparison of stem volume (d2h) with stem biomass suggested that tissue density was reduced by elevated O3. Biomass accumulation response to rainfall chemistry was small (5.5% reduction in the low pH treatment in 1989) and not statistically significant for most plant tissues. Growth response to soil Mg status was not significant. Hoewever, in 1989 treatment interactions between rainfall chemistry and soil Mg status were observed. Height was 5% greater (P = 0.02) and biomass was 6% greater (P = 0.10) in seedlings grown in higher-Mg soil and receiving higher-pH rainfall than seedlings grown in any of the other pH-Mg treatment combinations. The data suggest direct adverse effects of near ambient O3 and indirect, slower acting and interacting adverse effects of rainfall chemistry and soil nutrient status on growth of loblolly pine. C1 OAK RIDGE NATL LAB,TENNESSEE VALLEY AUTHOR,COOPERAT FOREST STUDIES PROGRAM,OAK RIDGE,TN 37831. DESERT RES INST,CTR BIOL SCI,RENO,NV 89506. RP EDWARDS, NT (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 32 TC 17 Z9 17 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD MAY PY 1992 VL 63 IS 1-2 BP 105 EP 118 DI 10.1007/BF00475625 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA HT937 UT WOS:A1992HT93700008 ER PT J AU THOMA, SG GALLEGOS, DP SMITH, DM AF THOMA, SG GALLEGOS, DP SMITH, DM TI IMPACT OF FRACTURE COATINGS ON FRACTURE MATRIX FLOW INTERACTIONS IN UNSATURATED, POROUS-MEDIA SO WATER RESOURCES RESEARCH LA English DT Article ID KNUDSEN DIFFUSION; CAPILLARY RISE; MODEL; WATER AB Groundwater flow in unsaturated, fractured rock is often assumed to be dominated by the porous matrix component. This is frequently the result of reasoning that water flowing in the fractures is rapidly imbibed into the rock matrix by capillary suction forces with negligible resistance to uptake at the fracture/matrix interface. However, the existence of a low-permeability mineralized layer or coating at this interface may substantially reduce matrix imbibition and could consequently result in fracture-dominated flow. To test this idea, four tuff samples containing natural fractures were obtained from tuff formations in southern Nevada. By performing imbibition experiments into the matrix rock, across a mineralized fracture face and then across a fresh uncoated fracture face, water uptake as a function of time and coating was measured. A model combining Darcy's law and the Washburn equation has been used to describe the imbibition behavior. Before testing the tuff samples, the experimental technique and imbibition model were first tested using ordered sphere packings with known pore size and structure. From the tuff imbibition data, the ratio of the permeability through the mineralized face to the permeability through the uncoated face was found to be 0.3 (relatively little effect of the mineralized layer) for two samples, 0.01 for one sample, and 10(-7) (uptake strongly restricted by the mineralized layer) for one sample. Using a simple fracture flow model and the imbibition model mentioned above to simulate matrix uptake from the fracture, numerical simulations indicate that the existence of fracture coatings could significantly decrease the travel time and increase the travel depth of water flowing through fractures. C1 SANDIA NATL LABS,DIV 6416,ALBUQUERQUE,NM 87185. RP THOMA, SG (reprint author), UNIV NEW MEXICO,NSF,CTR MICROENGN CERAM,ALBUQUERQUE,NM 87131, USA. NR 37 TC 59 Z9 60 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1992 VL 28 IS 5 BP 1357 EP 1367 DI 10.1029/92WR00167 PG 11 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA HT438 UT WOS:A1992HT43800016 ER PT J AU DAILY, W RAMIREZ, A LABRECQUE, D NITAO, J AF DAILY, W RAMIREZ, A LABRECQUE, D NITAO, J TI ELECTRICAL-RESISTIVITY TOMOGRAPHY OF VADOSE WATER-MOVEMENT SO WATER RESOURCES RESEARCH LA English DT Article ID IMPEDANCE-COMPUTED-TOMOGRAPHY; CONDUCTIVITY; INVERSION AB Cross borehole electrical resistivity tomography (ERT) was used to image the resistivity distribution before and during two infiltration experiments. In both cases water was introduced into the vadose zone, and the change in resistivity associated with the plume of wetted soil was imaged as a function of time. The primary purpose of this work was to study the capabilities and limitations of ERT to image underground structure and groundwater movement in the vadose zone. A secondary goal was to learn specifics of unsaturated flow in a complex geologic setting. Tomographs of electrical resistivity taken before infiltration image coarser, well-drained soils (sands and gravels) as more resistive zones, whereas finer grained soils (silts and clays), which hold more water by capillarity, are imaged as more conductive. Images of changes in resistivity during infiltration show growth of the water infiltration plume with time that is consistent with known geology. In the ERT images we see the effects of capillary barriers and infer differences between capillary-driven flow through fine sediments and gravity-driven flow through very permeable sediments. Images are consistent with numerical flow simulations using hydrological parameter values consistent with soil types inferred from well logs. ERT can be a useful tool to monitor movement of circuitous moisture fronts in a heterogeneous field setting that would go undetected by borehole measurements. C1 UNIV ARIZONA,DEPT MIN & GEOL ENGN,TUCSON,AZ 85719. RP DAILY, W (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-156,LIVERMORE,CA 94550, USA. NR 37 TC 251 Z9 258 U1 4 U2 59 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1992 VL 28 IS 5 BP 1429 EP 1442 DI 10.1029/91WR03087 PG 14 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA HT438 UT WOS:A1992HT43800023 ER PT J AU TSANG, YW AF TSANG, YW TI USAGE OF EQUIVALENT APERTURES FOR ROCK FRACTURES AS DERIVED FROM HYDRAULIC AND TRACER TESTS SO WATER RESOURCES RESEARCH LA English DT Article ID SINGLE FRACTURE; GROUNDWATER-FLOW; CHANNEL MODEL; FLUID-FLOW; TRANSPORT; VALIDITY AB In the literature during the past several years there appear numerous references to the "equivalent aperture" of a rough-walled rock fracture as derived from various hydraulic and tracer tests. However, the similar or even identical terms used by different researchers for "equivalent aperture" often do not have the same meaning. This has led to some confusion in the comparison of their results. In particular, there is a serious apparent contradiction in the claims of some authors that "equivalent apertures" derived from tracer tests are much larger than those derived from hydraulic tests, and the findings of others that apertures estimated from tracer tests are consistently smaller than those estimated from hydraulic tests. This apparent contradiction of the field results in fact arises from the different definitions of the so-called "tracer aperture" as employed by different researchers. In this short technical note I have attempted to sort out the different definitions, denotations and usage of the various "equivalent apertures" and show that there are mainly three alternative definitions used in the literature. The meaning of each as related to experimental measurements is explained and their interrelationship discussed. It is shown that once the specific definition of "equivalent aperture" referred to by each researcher is identified, then the relative magnitudes of these "equivalent apertures" as reported by different groups of researchers are perfectly consistent with each other. RP TSANG, YW (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720, USA. NR 17 TC 97 Z9 99 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1992 VL 28 IS 5 BP 1451 EP 1455 DI 10.1029/92WR00361 PG 5 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA HT438 UT WOS:A1992HT43800026 ER PT J AU CHEN, ZX BODVARSSON, GS WITHERSPOON, PA AF CHEN, ZX BODVARSSON, GS WITHERSPOON, PA TI EXACT INTEGRAL SOLUTIONS FOR 2-PHASE FLOW - COMMENT SO WATER RESOURCES RESEARCH LA English DT Note C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. NR 2 TC 12 Z9 12 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1992 VL 28 IS 5 BP 1477 EP 1478 DI 10.1029/92WR00473 PG 2 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA HT438 UT WOS:A1992HT43800030 ER PT J AU BAHADUR, S GONG, DL ANDEREGG, JW AF BAHADUR, S GONG, DL ANDEREGG, JW TI THE ROLE OF COPPER-COMPOUNDS AS FILLERS IN TRANSFER FILM FORMATION AND WEAR OF NYLON SO WEAR LA English DT Article ID POLYTETRAFLUOROETHYLENE; FRICTION; ESCA; BEHAVIOR; XPS AB The friction and wear behavior of filled nylon 11 composites was studied. The fillers used were CuS, CuO, CuF2, and Cu(C2H3O2)2.H2O (copper acetate). A fixed filler proportion of 35% by volume was used. Sliding tests were performed in a pin-on-disk configuration at 1.0 m s-1 speed and 0.65 MPa nominal contact pressure under ambient conditions. The pin was made of composite specimens and the disk of hardened tool steel. It was found that CuS, CuF2 and CuO as fillers reduced the wear rate of nylon while Cu(C2H3O2)2.H2O increased it. The cause of this behavior was investigated in terms of the ability of these materials to develop a transfer film and its bonding to the counterface. The wear rates of nylon and copper-acetate-filled nylon were high because the ability of nylon to form a transfer film was poor and the composite transfer film had poor adhesion to the counterface. On the other hand, the wear-resistant nylon composites which were filled with CuS, CuO and CuF2 transferred well to the counterface and their transfer films were thin, uniform and strongly adherent to the counterface. The adhesion of the transfer film to the counterface for CuO-nylon composite was investigated by X-ray photoelectron spectroscopy analysis. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP BAHADUR, S (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT MECH ENGN,AMES,IA 50011, USA. NR 27 TC 73 Z9 85 U1 1 U2 8 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD MAY 1 PY 1992 VL 154 IS 2 BP 207 EP 223 DI 10.1016/0043-1648(92)90155-2 PG 17 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA HR410 UT WOS:A1992HR41000001 ER PT J AU WANG, BQ GENG, GQ LEVY, AV RAO, M KEISER, J AF WANG, BQ GENG, GQ LEVY, AV RAO, M KEISER, J TI CHARACTERISTICS OF SCALE LAYERS ON STEELS IN FLUIDIZED-BED COMBUSTOR SERVICE SO WEAR LA English DT Article ID EROSION AB The characteristics of the scale deposit layers that form on and protect steel surfaces eroded-corroded at elevated temeperature, i.e. the composition distribution, morphology, deformation, thickness, porosity and mechanical integrity, were determined and related to metal wastage under various laboratory test and in-service conditions. It was found that in the outer part of the scale layer either straight bed material or a mixture of it and iron oxide can form. Near the scale-metal interface the bed material content of the layer was markedly decreased and consisted primarily of iron oxide. The gradation of the constituents through the layer were determined using line scan and X-ray maps. The distribution of iron and calcium had a linear gradient through an inner layer near the substrate interface. The iron, calcium and sulfur in the outer layer were neither linear nor could they be correlated with the distance from the outside surface to the scale layer-metal interface. The composition distribution depended on both the chemical and mechanical processes that occurred. In the inner layer the chemical process predominated and in the outer layer only the mechanical process occurred. The erosion-corrosion (E-C) scales that formed under the test conditions used appeared to be relatively ductile, even at room temperature. The microhardness of the E-C surface layers could not be correlated with the E-C metal wastage. However, the single-particle impact behavior of a preformed layer could be related to the E-C metal wastage. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP WANG, BQ (reprint author), XIAN INST HIGHWAYS,XIAN,PEOPLES R CHINA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD MAY 1 PY 1992 VL 154 IS 2 BP 331 EP 348 DI 10.1016/0043-1648(92)90163-3 PG 18 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA HR410 UT WOS:A1992HR41000009 ER PT J AU SCHILD, D GLASSNER, BJ MORTIMER, RK CARLSON, M LAURENT, BC AF SCHILD, D GLASSNER, BJ MORTIMER, RK CARLSON, M LAURENT, BC TI IDENTIFICATION OF RAD16, A YEAST EXCISION REPAIR GENE HOMOLOGOUS TO THE RECOMBINATIONAL REPAIR GENE RAD54 AND TO THE SNF2 GENE INVOLVED IN TRANSCRIPTIONAL ACTIVATION SO YEAST LA English DT Article DE DNA REPAIR GENES; TRANSCRIPTIONAL ACTIVATION; SEQUENCE HOMOLOGY; ZINC FINGERS; POTENTIAL HELICASES ID SACCHAROMYCES-CEREVISIAE; MOLECULAR ANALYSIS; DNA; EXPRESSION; MANIPULATION; SUPERFAMILY; PROTEINS; HELICASE; MUTANTS; ENZYME AB The RAD54 gene of Saccharomyces cerevisiae is involved in the recombinational repair of DNA damage. The predicted amino acid sequence of the RAD54 protein shows significant homologies with the yeast SNF2 protein, which is required for the transcriptional activation of a number of diversely regulated genes. These proteins are 31 % identical in a 492-amino acid region that includes presumed nucleotide and Mg2+ binding sites. We noted previously that the SNF2 protein also shares homology with a partial open reading frame (ORF) that was reported with the sequence of an adjacent gene. This ORF also shares homology with the RAD54 protein. To test whether this ORF is involved in transcriptional activation or DNA repair, yeast strains deleted for part of it have been isolated. These strains do not show a Snf-like phenotype, but they are UV sensitive. This gene has been identified as RAD16, a gene involved in the excision repair of DNA damage. Analysis of the rad]6 deletion mutations indicates that RAD16 encodes a non-essential function and is not absolutely required for excision repair. Outside the region of homology to RAD54 and SNF2, the predicted RAD 1 6 protein contains a novel cysteine-rich motif that may bind zinc and that has been found recently in eleven other proteins, including the yeast RAD18 protein. The homologies between RAD16, RAD54 and SNF2 are also shared by several additional, recently isolated yeast and Drosophila genes. C1 UNIV CALIF BERKELEY, DEPT MOLEC & CELL BIOL, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, GRAD GRP BIOPHYS, BERKELEY, CA 94720 USA. COLUMBIA UNIV COLL PHYS & SURG, DEPT GENET & DEV, NEW YORK, NY 10032 USA. COLUMBIA UNIV COLL PHYS & SURG, INST CANC RES, NEW YORK, NY 10032 USA. RP LAWRENCE BERKELEY LAB, DEPT CELL & MOLEC BIOL, BERKELEY, CA 94720 USA. FU NIGMS NIH HHS [GM30990, F32 GM11933, GM34095] NR 46 TC 62 Z9 63 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0749-503X EI 1097-0061 J9 YEAST JI Yeast PD MAY PY 1992 VL 8 IS 5 BP 385 EP 395 DI 10.1002/yea.320080506 PG 11 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Microbiology; Mycology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Microbiology; Mycology GA HV555 UT WOS:A1992HV55500005 PM 1626430 ER PT J AU ROSS, DK SPENCE, JR VARY, JP AF ROSS, DK SPENCE, JR VARY, JP TI MODEL FOR COLD DARK MATTER SO ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI LA English DT Article ID BHABHA SCATTERING; NUCLEOSYNTHESIS; POSITRON AB We present a model for cold dark matter based upon continuum bound states of the e+ e- system. These continuum bound states, referred to as photonium states to distinguish them from the well-known bound states of positronium, are shown to have cross sections and life-time properties consistent with abundant production in the early universe and survival to the present time. Thus photonium can easily account for more than 90% of the total mass of the universe. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP ROSS, DK (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011, USA. NR 19 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0939-7922 J9 Z PHYS A-HADRON NUCL JI Z. Phys. A.-Hadrons Nuclei PD MAY PY 1992 VL 342 IS 2 BP 239 EP 244 DI 10.1007/BF01288476 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA HW372 UT WOS:A1992HW37200018 ER PT J AU MAYER, RH FORNAL, B BRODA, R BEARDEN, IG GRABOWSKI, ZW LUNARDI, S DALY, PJ LAURITSEN, T CARPENTER, MP JANSSENS, RVF KHOO, TL LIANG, Y AF MAYER, RH FORNAL, B BRODA, R BEARDEN, IG GRABOWSKI, ZW LUNARDI, S DALY, PJ LAURITSEN, T CARPENTER, MP JANSSENS, RVF KHOO, TL LIANG, Y TI NEW 19/2+ ISOMERS IN SN-119, SN-121 AND SN-123 SO ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI LA English DT Note AB Yrast 19/2+ isomers in Sn-119, Sn-121 and Sn-123 with half-lives in the 5-10-mu-s range have been identified by gamma-ray spectroscopy following Sn-122, Sn-124 + 344 MeV Se-80 reactions (approximately 15% above the Coulomb barrier). Isomeric decay schemes are presented and discussed. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP MAYER, RH (reprint author), PURDUE UNIV,W LAFAYETTE,IN 47907, USA. RI Bearden, Ian/M-4504-2014; Carpenter, Michael/E-4287-2015 OI Bearden, Ian/0000-0003-2784-3094; Carpenter, Michael/0000-0002-3237-5734 NR 4 TC 16 Z9 16 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0939-7922 J9 Z PHYS A-HADRON NUCL JI Z. Phys. A.-Hadrons Nuclei PD MAY PY 1992 VL 342 IS 2 BP 247 EP 248 DI 10.1007/BF01288478 PG 2 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA HW372 UT WOS:A1992HW37200020 ER PT J AU MOLTZ, DM BATCHELDER, JC LANG, TF OGNIBENE, TJ CERNY, J HAUSTEIN, PE REEDER, PL AF MOLTZ, DM BATCHELDER, JC LANG, TF OGNIBENE, TJ CERNY, J HAUSTEIN, PE REEDER, PL TI BETA-DELAYED 2-PROTON DECAY OF TI-39 SO ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI LA English DT Article ID EMISSION; AR-31; AL-22 AB The beta-delayed two-proton decay of the T(z)=-5/2 nuclide Ti-39 has been observed. The Sc-39 isobaric analog state has been calculated to lie at 8.82 MeV using the measured two-proton sum energy of 4750 +/- 40 keV for its decay to the K-37 ground state. Combining this excitation energy with a Coulomb displacement energy calculation has lowered the energy available for ground state two-proton emission of Ti-39 from 760 to 530 keV. C1 BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. UNIV CALIF SAN FRANCISCO, PHYS RES LAB, SAN FRANCISCO, CA 94080 USA. RP MOLTZ, DM (reprint author), LAWRENCE BERKELEY LAB, DEPT CHEM, DIV NUCL SCI, BERKELEY, CA 94720 USA. RI Lang, Thomas/B-2685-2012 OI Lang, Thomas/0000-0002-3720-8038 NR 22 TC 26 Z9 26 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0939-7922 J9 Z PHYS A-HADRON NUCL JI Z. Phys. A.-Hadrons Nuclei PD MAY PY 1992 VL 342 IS 3 BP 273 EP 276 DI 10.1007/BF01291509 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA HY428 UT WOS:A1992HY42800004 ER PT J AU DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A CATANESI, MG CREANZA, D DEPALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BAUERDICK, LAT BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BOUDREAU, J BURNETT, TH DREVERMANN, H FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S HILGART, J JOST, B KASEMANN, M KNOBLOCH, J LACOURT, A LANCON, E LEHRAUS, I LOHSE, T LUSIANI, A MARCHIORO, A MARTINEZ, M MATO, P MENARY, S MEYER, T MINTEN, A MIOTTO, A MIQUEL, R MOSER, HG NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROLANDI, L ROTH, A ROTHBERG, J SAICH, M SCHLATTER, D SCHMELLING, M TEJESSY, W WACHSMUTH, H WASSERBAECH, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BADAUD, F BARDADINOTWINOWSKA, M BENCHEIKH, AM ELFELLOUS, R FALVARD, A GAY, P GUICHENEY, C HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PIETRZYK, B PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOS, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BRIENT, JC FOUQUE, G GAMESS, A HARVEY, J ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E MONETA, L PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CERUTTI, F CHIARELLA, V ETTOREPIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP PASSALACQUA, L PEPEALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O COLRAIN, P HALLEY, AW TENHAVE, I LYNCH, JG MAITLAND, W MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BROODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G JACKSON, D KEEMER, NR NUTTALL, M PATEL, A SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T KLEINKNECHT, K RAAB, J RENK, B ROEHN, S SANDER, HG SCHMIDT, H STEEG, F WALTHER, SM WOLF, B AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A CARR, J COYLE, P DRINKHARD, J ETIENNE, F PAPALEXIOU, S PAYRE, P QIAN, Z SCHWEMLING, P TALBY, M ROUSSEAU, D ADLUNG, S BECKER, H BLUM, W BROWN, D CATTANEO, P COWAN, G DEHNING, B DIETL, H DYDAK, F FERNANDEZBOSMAN, M HANSLKOSANECKA, T JAHN, A KOZANECKI, W LANGE, E LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R ROTSCHEIDT, H SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U STIEGLER, U STDENIS, R TAKASHIMA, M THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GRIVAZ, JF HEUSSE, P JANOT, P KIM, DW LEDIBERDER, F LEFRANCOIS, J LUTZ, AM SCHUNE, MH VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F ABBANEO, D AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELLORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GATTO, C GIASSI, A GIORGI, MA LIGABUE, F MANNELLI, EB MARROCCHESI, PS MESSINEO, A PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T QUASI, IS STRONG, JA WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCHDEVAUX, B COLAS, P LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERLAS, JA PERRIER, F RANDER, J RENARDY, F ROUSSARIE, A SCHULLER, JP SCHWINDLING, J VALLAGE, B ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, RF CARTWRIGHT, S COMBLEY, F DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BARBERIO, E BRANDT, S GRUPEN, C MEINHARD, H MIRABITO, L SCHAFER, U SEYWERD, H GANIS, G GIANNINI, G GOBBO, B RAGUSA, F BELLANTONI, L CINABRO, D CONWAY, JS COWEN, DF FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JARED, RC JOHNSON, RP LECLAIRE, BW LISHKA, C PAN, YB PATER, JR SAADI, Y SHARMA, V SHI, ZH TANG, YH WALSH, AM WEAR, JA WEBER, FV WHITNEY, MH WU, SL ZOBERNIG, G AF DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A CATANESI, MG CREANZA, D DEPALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BAUERDICK, LAT BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BOUDREAU, J BURNETT, TH DREVERMANN, H FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S HILGART, J JOST, B KASEMANN, M KNOBLOCH, J LACOURT, A LANCON, E LEHRAUS, I LOHSE, T LUSIANI, A MARCHIORO, A MARTINEZ, M MATO, P MENARY, S MEYER, T MINTEN, A MIOTTO, A MIQUEL, R MOSER, HG NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROLANDI, L ROTH, A ROTHBERG, J SAICH, M SCHLATTER, D SCHMELLING, M TEJESSY, W WACHSMUTH, H WASSERBAECH, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BADAUD, F BARDADINOTWINOWSKA, M BENCHEIKH, AM ELFELLOUS, R FALVARD, A GAY, P GUICHENEY, C HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PIETRZYK, B PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOS, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BRIENT, JC FOUQUE, G GAMESS, A HARVEY, J ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E MONETA, L PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CERUTTI, F CHIARELLA, V ETTOREPIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP PASSALACQUA, L PEPEALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O COLRAIN, P HALLEY, AW TENHAVE, I LYNCH, JG MAITLAND, W MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BROODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G JACKSON, D KEEMER, NR NUTTALL, M PATEL, A SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T KLEINKNECHT, K RAAB, J RENK, B ROEHN, S SANDER, HG SCHMIDT, H STEEG, F WALTHER, SM WOLF, B AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A CARR, J COYLE, P DRINKHARD, J ETIENNE, F PAPALEXIOU, S PAYRE, P QIAN, Z SCHWEMLING, P TALBY, M ROUSSEAU, D ADLUNG, S BECKER, H BLUM, W BROWN, D CATTANEO, P COWAN, G DEHNING, B DIETL, H DYDAK, F FERNANDEZBOSMAN, M HANSLKOSANECKA, T JAHN, A KOZANECKI, W LANGE, E LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R ROTSCHEIDT, H SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U STIEGLER, U STDENIS, R TAKASHIMA, M THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GRIVAZ, JF HEUSSE, P JANOT, P KIM, DW LEDIBERDER, F LEFRANCOIS, J LUTZ, AM SCHUNE, MH VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F ABBANEO, D AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELLORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GATTO, C GIASSI, A GIORGI, MA LIGABUE, F MANNELLI, EB MARROCCHESI, PS MESSINEO, A PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T QUASI, IS STRONG, JA WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCHDEVAUX, B COLAS, P LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERLAS, JA PERRIER, F RANDER, J RENARDY, F ROUSSARIE, A SCHULLER, JP SCHWINDLING, J VALLAGE, B ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, RF CARTWRIGHT, S COMBLEY, F DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BARBERIO, E BRANDT, S GRUPEN, C MEINHARD, H MIRABITO, L SCHAFER, U SEYWERD, H GANIS, G GIANNINI, G GOBBO, B RAGUSA, F BELLANTONI, L CINABRO, D CONWAY, JS COWEN, DF FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JARED, RC JOHNSON, RP LECLAIRE, BW LISHKA, C PAN, YB PATER, JR SAADI, Y SHARMA, V SHI, ZH TANG, YH WALSH, AM WEAR, JA WEBER, FV WHITNEY, MH WU, SL ZOBERNIG, G TI MEASUREMENT OF TAU BRANCHING RATIOS SO ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS LA English DT Article ID LEPTON PRODUCTION; CELLO DETECTOR; DECAY MODES; PETRA; PIONS; PARAMETERS AB Using the data accumulated at LEP in 1989 and 1990 with the ALEPH detector, the inclusive and exclusive branching ratios of the tau-lepton have been measured assuming lepton universality in Z0 decays. The inclusive branching fractions for the tau-decay into one, three, and five charged particles have been determined to be (85.45 +/- 0.97)%, (14.35 +/- 0.48)%, and (0.10 +/- 0.05)%, respectively, in agreement with the world averages. New undetected decay modes are determined to have a branching fraction of less than 2.1% at 95% CL. The measured branching ratios for quasi-exclusive channels are slightly larger than, but consistent with the world averages, except for the modes tau --> 3 hadrons + nu(tau) and tau --> hadron + 2-pi(0)nu(tau), which are significantly larger. These latter branching ratios have been found to be (9.5 +/- 0.7)% and (10.2 +/- 1.1)%, respectively. The sum of all the measured quasi-exclusive branching ratios is (100.4 +/- 1.8)%. A fully exclusive analysis of modes with neutral pions shows no evidence for new photonic decay modes with a branching fraction limit of 3.4% at 95% CL. C1 UNIV AUTONOMA BARCELONA,FIS ALTAS ENERGIAS LAB,E-08193 BARCELONA,SPAIN. IST NAZL FIS NUCL,SEZIONE BARI,I-70126 BARI,ITALY. UNIV BARI,DIPARTIMENTO FIS,I-70126 BARI,ITALY. CHINESE ACAD SCI,DEPT HIGH ENERGY PHYS,BEIJING,PEOPLES R CHINA. CERN,EUROPEAN LAB PARTICLE PHYS,CH-1211 GENEVA 23,SWITZERLAND. UNIV CLERMONT FERRAND,PHYS CORPUSCULAIRE LAB,CNRS,F-63177 CLERMONT FERRAND,FRANCE. NIELS BOHR INST,DK-2100 COPENHAGEN,DENMARK. DEMOCRITOS NUCL RES CTR,ATHENS,GREECE. ECOLE POLYTECH,PHYS NUCL & HAUTES ENERGIES LAB,CNRS,F-91128 PALAISEAU,FRANCE. UNIV EDINBURGH,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. UNIV FLORENCE,DIPARTIMENTO FIS,I-50125 FLORENCE,ITALY. IST NAZL FIS NUCL,SEZIONE FIS,I-50125 FLORENCE,ITALY. FLORIDA STATE UNIV,SUPERCOMP COMPUTAT RES INST,TALLAHASSEE,FL 32306. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV GLASGOW,DEPT PHYS & ASTRON,GLASGOW G12 8QQ,SCOTLAND. UNIV HEIDELBERG,INST HOCHENERGIEPHYS,W-6900 HEIDELBERG,GERMANY. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,DEPT PHYS,LONDON SW7 2BZ,ENGLAND. UNIV INNSBRUCK,INST EXPTL PHYS,A-6020 INNSBRUCK,AUSTRIA. UNIV LANCASTER,DEPT PHYS,LANCASTER LA1 4YB,ENGLAND. UNIV MAINZ,INST PHYS,W-6500 MAINZ,GERMANY. FAC SCI LUMINY,CTR PHYS PARTICULES,CNRS,F-13288 MARSEILLE,FRANCE. MAX PLANCK INST PHYS & ASTROPHYS,WERNER HEISENBERG INST PHYS,W-8000 MUNICH 40,GERMANY. UNIV PARIS 11,ACCELERATEUR LINEAIRE LAB,CNRS,F-91405 ORSAY,FRANCE. UNIV PISA,IST NAZL FIS NUCL,SEZIONE PISA,DIPARTIMENTO FIS,I-560100 PISA,ITALY. UNIV LONDON,ROYAL HOLLOWAY & BEDFORD NEW COLL,DEPT PHYS,SURREY TW20 0EX,ENGLAND. RUTHERFORD APPLETON LAB,DEPT PARTICLE PHYS,DIDCOT OX11 0QX,OXON,ENGLAND. CENS,DEPT PHYS PARTICULES ELEMENTAIRES,F-91191 GIF SUR YVETTE,FRANCE. UNIV SHEFFIELD,DEPT PHYS,SHEFFIELD S3 7RH,S YORKSHIRE,ENGLAND. UNIV SIEGEN,FACHBEREICH PHYS,W-5900 SIEGEN,GERMANY. UNIV TRIESTE,DIPARTIMENTO FIS,I-34127 TRIESTE,ITALY. IST NAZL FIS NUCL,SEZIONE TRIESTE,I-34127 TRIESTE,ITALY. UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. SLAG,STANFORD,CA 94309. UNIV WASHINGTON,SEATTLE,WA 98195. CNR,IST COSMOGEOFIS,TURIN,ITALY. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. CERN,DIV PPE,CH-1211 GENEVA 23,SWITZERLAND. NAPLES UNIV,DIPARTIMENTO SCI FIS,I-80138 NAPLES,ITALY. SCUOLA NORMALE SUPER PISA,I-56010 PISA,ITALY. RP DECAMP, D (reprint author), LAB PHYS PARTICULES,CNRS,IN2P3,F-74019 ANNECY LE VIEUX,FRANCE. RI Bosman, Martine/J-9917-2014; Fernandez, Enrique/L-5387-2014; Mir, Lluisa-Maria/G-7212-2015; ciocci, maria agnese /I-2153-2015; Hansen, John/B-9058-2015; Lusiani, Alberto/N-2976-2015; Marrocchesi, Pier Simone/N-9068-2015; Lusiani, Alberto/A-3329-2016; Murtas, Fabrizio/B-5729-2012; Booth, Christopher/B-5263-2016; Pacheco Pages, Andres/C-5353-2011; Ferrante, Isidoro/F-1017-2012; Focardi, Ettore/E-7376-2012; Venturi, Andrea/J-1877-2012; Perrier, Frederic/A-5953-2011; Rolandi, Luigi (Gigi)/E-8563-2013; Colas, Paul/F-2876-2013; Delfino, Manuel/A-1545-2012; ANTONELLI, ANTONELLA/C-6238-2011; Buttar, Craig/D-3706-2011; Stahl, Achim/E-8846-2011; Passalacqua, Luca/F-5127-2011; St.Denis, Richard/C-8997-2012; Forti, Francesco/H-3035-2011; Ligabue, Franco/F-3432-2014; OI Bosman, Martine/0000-0002-7290-643X; Fernandez, Enrique/0000-0002-6405-9488; Mir, Lluisa-Maria/0000-0002-4276-715X; ciocci, maria agnese /0000-0003-0002-5462; Hansen, John/0000-0002-8422-5543; Lusiani, Alberto/0000-0002-6876-3288; Marrocchesi, Pier Simone/0000-0003-1966-140X; Lusiani, Alberto/0000-0002-6876-3288; Booth, Christopher/0000-0002-6051-2847; Pacheco Pages, Andres/0000-0001-8210-1734; Ferrante, Isidoro/0000-0002-0083-7228; Focardi, Ettore/0000-0002-3763-5267; Rolandi, Luigi (Gigi)/0000-0002-0635-274X; Delfino, Manuel/0000-0002-9468-4751; Stahl, Achim/0000-0002-8369-7506; Forti, Francesco/0000-0001-6535-7965; RASO, Giuseppe/0000-0002-5660-3711; Palazzi, Paolo/0000-0002-4861-391X; Bottigli, Ubaldo/0000-0002-0666-3433; Ligabue, Franco/0000-0002-1549-7107; Bloch-Devaux, Brigitte/0000-0002-2463-1232; Martinez Rodriguez, Manel/0000-0002-9763-9155; Murtas, Fabrizio/0000-0002-7041-6541; Garrido Beltran, Lluis/0000-0001-8883-6539; Edgecock, Rob/0000-0002-7896-3312 NR 34 TC 38 Z9 38 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0170-9739 J9 Z PHYS C PART FIELDS JI Z. Phys. C-Part. Fields PD MAY PY 1992 VL 54 IS 2 BP 211 EP 228 PG 18 WC Physics, Particles & Fields SC Physics GA HV559 UT WOS:A1992HV55900004 ER PT J AU WANG, CZ XU, CH CHAN, CT HO, KM AF WANG, CZ XU, CH CHAN, CT HO, KM TI DISINTEGRATION AND FORMATION OF C-60 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Letter ID C-60; BUCKMINSTERFULLERENE; SPECTRA; CARBON AB The disintegration and formation of the C60 fullerene are studied using molecular dynamics simulations. The interactions between carbon atoms are described with a tight-binding potential model that yields structural and vibrational properties of the molecule in good agreement with experimental data. The simulations show that C60 is stable against spontaneous disintegration up to 5000 K. The cage formation process is also observed by cooling and compressing 60 carbon atoms from the gas phase. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,MICROELECTR RES CTR,AMES,IA 50011. RP WANG, CZ (reprint author), US DOE,AMES LAB,AMES,IA 50010, USA. NR 13 TC 77 Z9 77 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 30 PY 1992 VL 96 IS 9 BP 3563 EP 3565 DI 10.1021/j100188a001 PG 3 WC Chemistry, Physical SC Chemistry GA HR490 UT WOS:A1992HR49000001 ER PT J AU WERST, DW AF WERST, DW TI RADICAL CATION COMPLEXES FORMED BY PI-LONE PAIR INTERACTIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON-SPIN-RESONANCE; DETECTED MAGNETIC-RESONANCE; PULSE-RADIOLYSIS; ORGANIC SULFIDES; FLUORESCENCE; DYNAMICS; SPECTRA; BONDS AB Time-resolved fluorescence-detected magnetic resonance (FDMR) is used to observe radical cations of thioethers in alkane and aromatic hydrocarbon solvents. Monomeric sulfide radical cations are stabilized at temperatures less than approximately 250 K in aromatic solvents such as toluene by electron donation from the solvent. The resulting arene-thioether complex radical cations are examples of mixed complex radical cations involving the interaction between lone-pair and pi-orbitals. The solvent interaction inhibits reactions of thioether radical cations (dimer formation and probably proton loss) and retards other radical cation reactions, such as dimer exchange. RP WERST, DW (reprint author), ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. NR 39 TC 20 Z9 20 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 30 PY 1992 VL 96 IS 9 BP 3640 EP 3646 DI 10.1021/j100188a017 PG 7 WC Chemistry, Physical SC Chemistry GA HR490 UT WOS:A1992HR49000017 ER PT J AU FAILOR, RA SOUERS, PC MAGNOTTA, F PRUSSIN, SG AF FAILOR, RA SOUERS, PC MAGNOTTA, F PRUSSIN, SG TI OZONE PRODUCTION IN THE REACTION OF T2 AND O2 GAS - A COMPARISON OF EXPERIMENTAL RESULTS AND MODEL PREDICTIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID KINETICS AB Ozone, predicted to be an important intermediate species in T2 oxidation, was monitored in situ by UV absorption spectroscopy for 0.01-1.0 mol % T2 in O2 (1 atm, 298 K). These are the first measurements of a tritium oxidation reaction intermediate. The experimental results were compared with the predictions of our comprehensive model of tritium oxidation. The experimentally determined temporal variation in ozone concentration is qualitatively reproduced by the model. As predicted, the measured initial rate of ozone production varied linearly with the initial T2 concentration ([T2]0), but with a value one-third of that predicted. The steady-state ozone concentration ([O3]SS) was predicted to be dependent on [T2]0(0.3), but measured values showed a [T2]0(0.6) dependence, resulting in [O3]SS a factor of 4 larger than predicted for a 1.0% T2-O2 mixture. Addition of H-2 to the T2-O2 mixture, to differentiate between the radiolytic and chemical behavior of the tritium, produced a decrease in [O3]SS which was larger than predicted. Changing the reaction cell surface-to-volume ratio showed indications of minor surface removal of ozone. No reasonable variation in model input parameters brought both the predicted initial ozone production rates and steady-state concentrations of ozone into agreement with the experimental results. Though qualitative agreement was achieved, further studies, with emphasis on surface effects, are necessary to explain quantitative differences and gain a greater understanding of the oxidation mechanism. C1 UNIV CALIF BERKELEY,DEPT NUCL ENGN,BERKELEY,CA 94720. RP FAILOR, RA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 28 TC 0 Z9 1 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 30 PY 1992 VL 96 IS 9 BP 3742 EP 3752 DI 10.1021/j100188a034 PG 11 WC Chemistry, Physical SC Chemistry GA HR490 UT WOS:A1992HR49000034 ER PT J AU WOLDEGABRIEL, G GOFF, F AF WOLDEGABRIEL, G GOFF, F TI K/AR DATES OF HYDROTHERMAL CLAYS FROM CORE HOLE VC-2B, VALLES CALDERA, NEW-MEXICO AND THEIR RELATION TO ALTERATION IN A LARGE HYDROTHERMAL SYSTEM SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article ID ACTIVE GEOTHERMAL SYSTEM; DIEGO CANYON IGNIMBRITES; JEMEZ VOLCANIC FIELD; BANDELIER TUFF; REDONDO DOME; MOUNTAINS; ZONE; GEOCHEMISTRY; CALIFORNIA; INDICATOR AB Seventeen K/Ar dates were obtained on illitic clays within Valles caldera ( 1. 13 Ma) to investigate the impact of hydrothermal alteration on Quaternary to Precambrian intracaldera and pre-caldera rocks in a large, long-lived hydrothermal system (approximately 1.0 Ma to present). Clay samples came from scientific core hole VC-2B (295-degrees-C at 1762 m) which was spudded in the Sulphur Springs thermal area and drilled into the boundary between the central resurgent dome and the western ring-fracture zone. Six illitic clays within Quaternary caldera-fill debris flow, tuffaceous sediment, and ash-flow tuff (48 to 587 m depth) yield ages from 0.35 to 1.09 Ma. Illite from Miocene pre-caldera sandstone (765 m) gives an age of 6.74 Ma. Two dates on illite from sandstones in Permian red beds (1008 and 1187 m) are 4.33 and 4.07 Ma, respectively. Surprisingly, three dates on illites from altered andesite pebbles within the red beds (1010-1014 m) are 0.95 to 1.06 Ma. Four illite dates on variably altered Precambrian quartz monzonite (1615-1762 m) range from 2.90 to 276 Ma. Post-Valles age illite is not correlated with alteration style (argillic to propylitic). Rather, post-Valles ages are uniformly obtained from illites in highly fractured, intensely altered, caldera-fill rocks and the Permian volcanic clasts. Generally, finer clay fractions from identical samples yield younger ages. Plots of Ar-40/Ar-36 versus K-40/Ar-36 and Ar-40* versus K-40 for the illites in caldera-fill rocks lie close to a 1-Ma isochron. Most illite dates older than Valles caldera are difficult to interpret because they correspond to the ages of pre-Valles volcanic and hydrothermal episodes in the Jemez volcanic field (less-than-or-equal-to 13 Ma). In addition, older dates may be caused by co-mingling of different illites during sample preparation, or by inherited argon or lost argon in illites from rocks with potentially complex hydrothermal histories. However, the range of ages obtained from illites in Permian sands and pebbles and from Precambrian crystalline rocks indicates that Valles hydrothermal activity is overwhelming illite produced by earlier geologic events. RP WOLDEGABRIEL, G (reprint author), LOS ALAMOS NATL LAB,DIV EARTH & ENVIRONM SCI,EES-1,MS D462,LOS ALAMOS,NM 87545, USA. NR 72 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD APR 30 PY 1992 VL 50 IS 3 BP 207 EP 230 DI 10.1016/0377-0273(92)90094-T PG 24 WC Geosciences, Multidisciplinary SC Geology GA HY659 UT WOS:A1992HY65900001 ER PT J AU COHN, JD DYKSTRA, H AF COHN, JD DYKSTRA, H TI THE MARINARI-PARISI MODEL AND COLLECTIVE FIELD-THEORY SO MODERN PHYSICS LETTERS A LA English DT Article AB We derive the supersymmetric collective field theory for the Marinari-Parisi model. For a specific choice of the superpotential, to leading order we find a one-parameter family of ground states which can be connected via instantons. At this level of analysis the instanton size implied by the underlying matrix model does not appear. RP COHN, JD (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-7323 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD APR 30 PY 1992 VL 7 IS 13 BP 1163 EP 1173 DI 10.1142/S0217732392003621 PG 11 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA HU035 UT WOS:A1992HU03500008 ER PT J AU CHASMAN, RR AF CHASMAN, RR TI THE FERMION DYNAMIC SYMMETRY MODEL AND SUPERDEFORMATION NEAR A=220 SO PHYSICS LETTERS B LA English DT Article ID INTERACTING BOSON MODEL; MASS REGION; STATES; DEFORMATION; OCTUPOLE; LIMIT AB The FDSM prediction of oblate superdeformed minima in nuclides with 84 < Z < 90 and 124 < N < 130 is studied with a Strutinsky method calculation of energy surfaces. Oblate superdeformed minima are found for slightly heavier nuclides. A critique of the application of the FDSM in the heavy elements is presented. Prolate superdeformation near A = 220 is re-examined. RP CHASMAN, RR (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 30 PY 1992 VL 280 IS 3-4 BP 187 EP 190 DI 10.1016/0370-2693(92)90053-7 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HV984 UT WOS:A1992HV98400003 ER PT J AU LIU, YJ LEVY, AV AF LIU, YJ LEVY, AV TI THE EROSION AND EROSION CORROSION OF CHROMIZED STEEL SO SURFACE & COATINGS TECHNOLOGY LA English DT Article AB The erosion and erosion-corrosion of chromized coatings on carbon and tool steels were investigated under test conditions which simulated those in the convection pass superheater tube banks of circulating fluidized-bed combustors. Coatings diffused by several different processes were obtained from coating suppliers and compared with a plasma-sprayed nickel-alloy-bonded chromium carbide composite. The two layers of chromized coatings, i.e. the hard brittle outer intermetallic layer and the more ductile Cr-Fe alloy layer eroded by different mechanisms at different rates. The plasma-sprayed nickel alloy-chromium carbide material had the lowest material wastage rate. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP LIU, YJ (reprint author), TSING HUA UNIV,BEIJING 100084,PEOPLES R CHINA. NR 7 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 30 PY 1992 VL 52 IS 2 BP 119 EP 128 DI 10.1016/0257-8972(92)90036-A PG 10 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HT942 UT WOS:A1992HT94200003 ER PT J AU ZAITSEV, SY KALABINA, NA ZUBOV, VP LUKASHEV, EP KONONENKO, AA UPHAUS, RA AF ZAITSEV, SY KALABINA, NA ZUBOV, VP LUKASHEV, EP KONONENKO, AA UPHAUS, RA TI MONOLAYERS OF PHOTOSYNTHETIC REACTION CENTERS OF GREEN AND PURPLE BACTERIA SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON LANGMUIR-BLODGETT FILMS CY AUG 26-30, 1991 CL PARIS, FRANCE ID LANGMUIR-BLODGETT-FILMS AB Monolayers of the reaction centers isolated from the photosynthetic bacteria Chloroflexus aurantiacus, Rhodobacter sphaeroides and Rhodopseudomonas viridis were prepared and investigated. The monolayer characteristics of these proteins were analyzed to determine the optimum conditions for stable film preparations. Monolayers were transferred onto quartz and metal supports by the Langmuir-Schaefer method to provide multilayers of definite thickness. These films retain the optical and photoelectrical properties of the native photosynthetic membranes. The sign of the photopotential provides evidence for a different orientation of the reaction centers of Rb. sphaeroides compared to those of Rps. viridis. C1 MV LOMONOSOV STATE UNIV,DEPT BIOPHYS,MOSCOW 119899,USSR. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP ZAITSEV, SY (reprint author), ACAD SCI USSR,INST BIOORGAN CHEM,MOSCOW 117871,USSR. RI Zaitsev, Sergei/B-9662-2014 OI Zaitsev, Sergei/0000-0003-1533-8680 NR 7 TC 22 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 30 PY 1992 VL 210 IS 1-2 BP 723 EP 725 DI 10.1016/0040-6090(92)90385-O PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HV025 UT WOS:A1992HV02500086 ER PT J AU RASER, LN THOMAS, LL KIM, JH COTTON, TM UPHAUS, RA AF RASER, LN THOMAS, LL KIM, JH COTTON, TM UPHAUS, RA TI FACTORS DETERMINING STABILITY OF BACTERIOCHLOROPHYLL MONOLAYERS SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON LANGMUIR-BLODGETT FILMS CY AUG 26-30, 1991 CL PARIS, FRANCE ID RESONANCE RAMAN-SPECTRA AB This study identifies the important chemical and physical factors determining the integrity of bacteriochlorophyll monolayers; these must be known if this pigment is to be used for model systems of the in vivo photosynthetic process. Spread monolayers of bacteriochlorophyll were subjected to variation of pH, temperature, subphase composition, incident light flux and atmospheres of various composition. Results were consistent with intuitive prediction as well as the known behavior of monolayers of chlorophyll a. Minimal decomposition was noted under conditions of darkness, presence of reducing agents either in the subphase or as an integral part of the monolayer, subambient temperatures, inert atmospheres and alkaline subphase pH. Major products arising from oxidative decomposition were 2'-desvinyl chlorophyll a, bacteriopheophytin, methyl bacteriopheophorbide and 10-hydroxy-bacteriochlorophyll a. C1 IOWA STATE UNIV,USDOE,AMES LAB,AMES,IA 50010. RP RASER, LN (reprint author), IOWA STATE UNIV,USDOE,DEPT CHEM,AMES,IA 50010, USA. NR 8 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 30 PY 1992 VL 210 IS 1-2 BP 753 EP 755 DI 10.1016/0040-6090(92)90394-Q PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HV025 UT WOS:A1992HV02500095 ER PT J AU YE, SY KIM, JH UPHAUS, RA COTTON, TM LU, TG DONG, SJ AF YE, SY KIM, JH UPHAUS, RA COTTON, TM LU, TG DONG, SJ TI ELECTROCHEMICAL-BEHAVIOR OF N-METHYL-N'-HEXADECYLVIOLOGEN MONOLAYERS ON SILVER ELECTRODES - EFFECTS OF COUNTERIONS SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON LANGMUIR-BLODGETT FILMS CY AUG 26-30, 1991 CL PARIS, FRANCE ID LANGMUIR-BLODGETT METHOD; SURFACES; GOLD AB N-Methyl-N'-hexadecylviologen (C16MV) has been the subject of several electrochemical and spectroelectrochemical studies which characterized the species present in various redox states for C16MV monolayers on silver electrode surfaces. Both self-assembled monolayers (SA) and Langmuir-Blodgett (LB) transferred systems have been studied. These indicated inconsistencies regarding the presence or absence of splitting of the first reduction peak in its cyclic voltammogram (CV). The present study demonstrates the important influence of the specific anionic species present in the supporting electrolyte. Splitting may or may not take place, depending on the size and relative strength of the adsorption of specific anions contributed by the supporting electrolyte. Small, strongly adsorbing anions such as iodide produced peak splitting in the CV of C16MV monolayers; bulky but weakly adsorbing anions such as perchlorate may disrupt the ordered structure of monolayers but produce no splitting. Ancillary data provided by surface enhanced Raman spectroscopy (SERS) was consistent with the electrochemical measurements. C1 ACAD SINICA,CHANGCHUN INST APPL CHEM,ELECTROANALYT CHEM LAB,CHANGCHUN 130022,PEOPLES R CHINA. IOWA STATE UNIV SCI & TECHNOL,USDOE,AMES LAB,AMES,IA 50011. RP YE, SY (reprint author), IOWA STATE UNIV SCI & TECHNOL,USDOE,DEPT CHEM,AMES,IA 50011, USA. NR 8 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 30 PY 1992 VL 210 IS 1-2 BP 822 EP 824 DI 10.1016/0040-6090(92)90414-7 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HV025 UT WOS:A1992HV02500115 ER PT J AU KIM, JH LEE, KAB UPHAUS, RA COTTON, TM AF KIM, JH LEE, KAB UPHAUS, RA COTTON, TM TI GOLD SURFACE ENHANCED RAMAN-SPECTROSCOPY OF AMPHIPHILIC SULFUR VIOLOGENS DURING ELECTRON-TRANSFER SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON LANGMUIR-BLODGETT FILMS CY AUG 26-30, 1991 CL PARIS, FRANCE ID MONOLAYERS AB Surface enhanced Raman spectroscopy (SERS) was used to characterize electron transfer through mediators present as self-assembled monolayers on gold electrode surfaces. The surface active species were three alkyl sulfides with the general structure: [octadecyl]-S-[CH2]n-[viologen]-[CH2]m dibromide, in which n was 5, 7 and 10, and the sum of n and m held constant. These structures thus present the electroactive moiety at varying distances from the surface upon which they are adsorbed. Cyclic voltammetry was used to confirm results of previous measurements on silver, after which SERS spectroelectrochemistry was used to identify the electroactive species formed following the electron transfer steps. Electrochemistry indicated that electron transfer was inversely proportional to the distance of the viologen from the gold surface; spectroelectrochemistry using SERS corroborated this, as the intensity of Raman scattering in SERS is a function of the distance of a scattering chromophore from the metal surface with which it is associated. Spectra of viologens were obtained for the neutral and radical species. Analysis of these data indicates agreement with the previous purely electrochemical studies of these compounds. These studies extend the utility of SERS spectroscopy for monolayer characterization by using gold surfaces to provide enhancement; silver surfaces have usually been used in previous SERS spectroelectrochemical studies. SERS employing gold surfaces may be especially significant in the case of biological molecules, because excitation in the red spectral regions greatly reduces background fluorescence, and a significantly decreased risk of photodecomposition is assured. For example, observation of gold SERS of chlorophyll or heme proteins by excitation into their Q-bands will permit acquisition of new information regarding these important compounds [cf. 6]. C1 SC JOHNSON & SON INC,DIV RES,RACINE,WI 53403. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP KIM, JH (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 6 TC 14 Z9 14 U1 1 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 30 PY 1992 VL 210 IS 1-2 BP 825 EP 827 DI 10.1016/0040-6090(92)90415-8 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HV025 UT WOS:A1992HV02500116 ER PT J AU ECKERT, J KUBAS, GJ WHITE, RP AF ECKERT, J KUBAS, GJ WHITE, RP TI THE BARRIER TO ROTATION OF DIHYDROGEN IN CR(CO)3(PCY3)2(ETA-2-H2), A COMPLEX WITH AN UNUSUALLY HIGH DIFFERENCE IN SOLID-STATE AND SOLUTION-STATE STABILITIES SO INORGANIC CHEMISTRY LA English DT Note ID MOLECULAR-HYDROGEN COMPLEXES; NEUTRON-SCATTERING; TRANSITION-METALS; NITROGEN; LIGANDS; MO AB The third member in the group 6 series of dihydrogen complexes, Cr(CO)3(PCy3)2(eta(2)-H2), has been synthesized as a solid which completely dissociates H2 in solution. Inelastic neutron scattering showed the barrier to rotation of the eta(2)-H2 to be 1.3 kcal/mol, compared to 1.7 and 2.2 kcal/mol for the Mo and W analogues. Nu(s)(M-H2) and nu(as)(M-H2) occurred at 950 and 1540 cm-1, similar to that for M = W but higher than for M = Mo (nu(s) = 885 cm-1). These results indicate that the overall M-H2 bond strength is less for Mo than for either Cr or W, but that d-pi --> sigma* H2 back-bonding is lowest for Cr. C1 INST MAX VON LAUE PAUL LANGEVIN,INC-4 GRP,F-38042 GRENOBLE,FRANCE. RP ECKERT, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LANSCE GRP,MS-H805,LOS ALAMOS,NM 87545, USA. NR 19 TC 21 Z9 21 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 29 PY 1992 VL 31 IS 9 BP 1550 EP 1551 DI 10.1021/ic00035a004 PG 2 WC Chemistry, Inorganic & Nuclear SC Chemistry GA HR759 UT WOS:A1992HR75900004 ER PT J AU CLARK, DL WATKIN, JG HUFFMAN, JC AF CLARK, DL WATKIN, JG HUFFMAN, JC TI PREPARATION AND X-RAY CRYSTAL-STRUCTURE OF K[ND(O-2,6-I-PR2C6H3)4] - A ONE-DIMENSIONAL CHAIN OF LANTHANIDE ARYLOXIDE ANIONS JOINED BY BIS(ETA-6-ARENE)-POTASSIUM INTERACTIONS SO INORGANIC CHEMISTRY LA English DT Note ID TRICOORDINATE CERIUM(III) ARYLOXIDES; MONOMERIC LN(OR)3 COMPLEXES; PERTURBED-PI-SYSTEMS; = TETRAHYDROFURAN; REACTIVITY; GADOLINIUM; ALKOXIDES; CHEMISTRY; POTASSIUM; YTTRIUM AB Reaction of NdCl3 with 3 equiv of potassium 2,6-diisopropylphenoxide in THF solution forms the salt K[Nd(O-2,6-i-Pr2C6H3)4]. The [Nd(OAr)4-] anion is pseudotetrahedral, while the potassium cation displays a novel bis(eta(6)-arene) interaction with the arene rings of aryloxide ligands of adjacent anions, thereby forming an quasi-one-dimensional infinite chain structure. This example of a lanthanide infinite chain structure based upon a bis(eta(6)-arene)-alkali-metal interaction appears to be without precendent. C1 INDIANA UNIV,CTR MOLEC STRUCT,BLOOMINGTON,IN 47405. RP CLARK, DL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPE & NUCL CHEM,MAIL STOP G739,LOS ALAMOS,NM 87545, USA. RI Clark, David/A-9729-2011 NR 42 TC 61 Z9 61 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 29 PY 1992 VL 31 IS 9 BP 1554 EP 1556 DI 10.1021/ic00035a006 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA HR759 UT WOS:A1992HR75900006 ER PT J AU CLARK, DL FRANKCOM, TM MILLER, MM WATKIN, JG AF CLARK, DL FRANKCOM, TM MILLER, MM WATKIN, JG TI FACILE SOLUTION ROUTES TO HYDROCARBON-SOLUBLE LEWIS BASE ADDUCTS OF THORIUM TETRAHALIDES - SYNTHESIS, CHARACTERIZATION, AND X-RAY STRUCTURE OF THBR4(THF)4 SO INORGANIC CHEMISTRY LA English DT Article ID HYDROGEN-DEUTERIUM EXCHANGE; BOND DISRUPTION ENTHALPIES; F-ELEMENT THERMOCHEMISTRY; SURFACE-CHEMISTRY; TRIVALENT URANIUM; ORGANOACTINIDES; (PENTAMETHYLCYCLOPENTADIENYL)THORIUM; TETRAHYDROFURAN; DERIVATIVES; REACTIVITY AB The direct combination of thorium metal turnings with 2 equiv of elemental bromine or iodine in THF solution at 0-degrees-C provides white crystalline ThX4(THF)4 (X = Br, 1; X = 1, 2; THF = tetrahydrofuran), in 70-80% isolated yield. These new compounds are soluble in hydrocarbon solvents and react readily with oxygen- and nitrogen-donor ligands in toluene solution to give ThBr4py4 (3), ThI4py4 (4), ThBr4(NCMe)4, (5), and ThBr4(DME)2 (6) in high yield (py = pyridine, DME = 1,2-dimethoxyethane). Compounds 1-6 have been characterized by elemental and thermogravimetric analysis, H-1 NMR, infrared, and diffuse-reflectance spectroscopy, and, for 1, a single-crystal X-ray structure determination. The X-ray diffraction study of 1 revealed a slightly distorted dodecahedral coordination geometry about the central thorium atom with two interpenetrating tetrahedra of bromide and THF ligands. Oxygen atoms of the THF ligands occupy A vertices (Th-O = 2.549 (17) angstrom, average) and bromide ions occupy B vertices (Th-Br = 2.859 (3) angstrom, average) of an irregular dodecahedron. 1 is an excellent synthetic precursor to thorium coordination and organometallic complexes and can be prepared on a 100-150-g scale in a single day. Crystal data for 1 (at -40-degrees-C): Rhombohedral space group R3BAR, with a = 26.317 (4) angstrom, c = 18.340 (4) angstrom, V = 11000 angstrom 3, d(calc) = 2.299 g cm-3, and Z = 18. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPE & NUCL CHEM,INORGAN & STRUCT CHEM GRP,LOS ALAMOS,NM 87545. COLORADO STATE UNIV,DEPT CHEM,FT COLLINS,CO 80523. RP CLARK, DL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,NUCL & RADIOCHEM GRP,INC-11,LOS ALAMOS,NM 87545, USA. RI Clark, David/A-9729-2011 NR 44 TC 41 Z9 41 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 29 PY 1992 VL 31 IS 9 BP 1628 EP 1633 DI 10.1021/ic00035a021 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA HR759 UT WOS:A1992HR75900021 ER PT J AU GOURLEY, PL FRITZ, IJ BRENNAN, TM HAMMONS, BE MCDONALD, AE MYERS, DR AF GOURLEY, PL FRITZ, IJ BRENNAN, TM HAMMONS, BE MCDONALD, AE MYERS, DR TI EPITAXIAL SURFACE-EMITTING LASER ON A LATTICE-MISMATCHED SUBSTRATE SO APPLIED PHYSICS LETTERS LA English DT Article AB We have demonstrated continuous-wave, room-temperature, photopumped operation ot a vertical-cavity surface-emitting laser having a 0.8% lattice mismatch with its GaAs substrate. Such mismatch provides flexibility in designing resonators with new lasing wavelengths. The laser resonator comprises lattice-matched In0.12Ga0.88As and In0.10Al0.90As quarter-wave layers for mirrors and a strained-layer superlattice of In0.23Ga0.77As/Al0.35Ga0.65As for an active region. The structure lases in the range 1.05- 1.10-mu-m under continuous-wave photoexcitation in the wavelength range 900-950 nm. The differential power efficiency is as high as 68% and the threshold is 2 kW/cm2 (1.8 kA/cm2 injection current-density equivalent). Dislocation line densities observed by photoluminescence microscopy are about 6 X 10(2)/CM in both the active region and the uppermost mirror layers. The lines predominate along one <110> direction along which the laser light is preferentially polarized. These observations suggest a way of polarizing surface-emitting lasers by intentional patterning of grating lines on the wafer surface. RP GOURLEY, PL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 4 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 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2057 EP 2059 DI 10.1063/1.107088 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000005 ER PT J AU COOGAN, JJ ROSE, EA AF COOGAN, JJ ROSE, EA TI OBSERVATION OF SCREENING EFFECT IN LARGE-AREA, COLD-CATHODE DIODES SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRON AB In this work we report the first observation of the screening effect in large-area, cold-cathode diodes. A framing camera was used to observe the formation of emission centers (ECs) on a 200 cm2 velvet emitter. The density of ECs increased as a function of applied magnetic field as predicted. The current per EC decreased as the magnetic field was increased. These phenomena suggest methods of increasing the spatial and temporal uniformity of high-power electron beams. RP COOGAN, JJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 12 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2062 EP 2064 DI 10.1063/1.107439 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000007 ER PT J AU LUCAS, CA LORETTO, D AF LUCAS, CA LORETTO, D TI NEW INSIGHT INTO THE STRUCTURE AND GROWTH OF CAF2/SI(111) SO APPLIED PHYSICS LETTERS LA English DT Article ID INTERFACE; TEMPERATURE; EPITAXY AB We have used transmission electron microscopy and x-ray crystal truncation rod measurements to investigate thin ( < 50 angstrom) CaF2 films grown on Si ( 111 ) substrates by molecular beam epitaxy. The results indicate that CaF2/Si can be structurally as perfect as NiSi2/Si and CoSi2/Si, and that a reconstructed layer is present at the CaF2/Si(111) interface. RP LUCAS, CA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720, USA. OI Lucas, Christopher/0000-0001-5743-3868 NR 18 TC 31 Z9 31 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2071 EP 2073 DI 10.1063/1.107092 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000010 ER PT J AU ONG, TP XIONG, FL CHANG, RPH WHITE, CW AF ONG, TP XIONG, FL CHANG, RPH WHITE, CW TI MECHANISM FOR DIAMOND NUCLEATION AND GROWTH ON SINGLE-CRYSTAL COPPER SURFACES IMPLANTED WITH CARBON SO APPLIED PHYSICS LETTERS LA English DT Article ID GRAPHITE FORMATION; FILM; DEPOSITION AB The nucleation and growth of diamond crystals on single-crystal copper surfaces implanted with carbon ions has been studied. Microwave plasma-enhanced chemical vapor deposition was used for diamond growth. The single-crystal copper substrates were implanted either at room temperature or at elevated temperature (approximately 820-degrees-C) with carbon ions prior to diamond nucleation. This procedure leads to the formation of a graphite film on the copper surface which greatly enhances diamond crystallite nucleation. From our study we construct a simple lattice model for diamond growth on graphite as <111> diamond parallel to <0001> graphite and <110> diamond parallel to <1120BAR> graphite. C1 NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Chang, R.P.H/B-7505-2009 NR 16 TC 29 Z9 31 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2083 EP 2085 DI 10.1063/1.107096 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000014 ER PT J AU EVERIST, SC MILLER, SL MCWHORTER, PJ AF EVERIST, SC MILLER, SL MCWHORTER, PJ TI MODELING THE CYCLING DEGRADATION OF SILICON-OXIDE-NITRIDE-OXIDE-SEMICONDUCTOR TRANSISTORS SO APPLIED PHYSICS LETTERS LA English DT Article ID NONVOLATILE TRANSISTORS; RETENTION; TEMPERATURE AB A model has been developed to predict cycling-induced threshold voltage shifts of silicon-oxide-nitride-oxide-semiconductor transistors. The model is based on the mechanism of hole transport through the tunnel oxide. It has been experimentally demonstrated that the model accurately predicts cycling behavior for a wide range of cycling parameters. Only two simple experiments are required to determine the model parameters. RP EVERIST, SC (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2101 EP 2103 DI 10.1063/1.107102 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000020 ER PT J AU PORTELLA, MT BIGOT, JY SCHOENLEIN, RW CUNNINGHAM, JE SHANK, CV AF PORTELLA, MT BIGOT, JY SCHOENLEIN, RW CUNNINGHAM, JE SHANK, CV TI K-SPACE CARRIER DYNAMICS IN GAAS SO APPLIED PHYSICS LETTERS LA English DT Article ID PHOTOEXCITED CARRIERS; QUANTUM WELLS; RELAXATION AB We investigate the k-space scattering dynamics of carriers in GaAs by measuring the transient relaxation of an anisotropic population produced by a linearly polarized 9 femtosecond infrared pulse. The redistribution of carrier momentum is shown to occur in the first tens of femtoseconds after excitation, and the relaxation times are found to vary with carrier density, from 25 to 60 fs for a carrier density range from 8 X 10(17) to 8 X 10(16) cm-3. Our results indicate that carrier momentum is rapidly redistributed via carrier-carrier scattering, and the nature of the density dependence suggests that the scattering is mediated by a screened Coulomb interaction between the carriers. RP PORTELLA, MT (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Schoenlein, Robert/D-1301-2014 OI Schoenlein, Robert/0000-0002-6066-7566 NR 19 TC 44 Z9 44 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2123 EP 2125 DI 10.1063/1.107083 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000028 ER PT J AU ASHBY, CIH MARTENS, J PLUT, TA GINLEY, DS PHILLIPS, JM AF ASHBY, CIH MARTENS, J PLUT, TA GINLEY, DS PHILLIPS, JM TI IMPROVED AQUEOUS ETCHANT FOR HIGH T(C) SUPERCONDUCTOR MATERIALS SO APPLIED PHYSICS LETTERS LA English DT Article ID FILMS AB We have developed an aqueous etchant suitable for producing feature sizes of 1-mu-m or less in YBa2Cu3O7 and TlBaCaCuO while not degrading high-frequency surface resistance. The 10%-300% increase in surface resistance previously seen in aqueous solutions is largely due to the presence of dissolved CO2; decarbonation of the water by bubbling N2 before and during etching can produce a better than 50% reduction in the surface-resistance degradation. Surface-resistance degradation can be further reduced by selecting the appropriate solution pH for ethylenediaminetetraacetic acid (EDTA)-based etchants. We have minimized increases in surface resistance to less than 5% following etching in decarbonated disodium EDTA solutions for both YBa2Cu3O7 and TlBaCaCuO superconductors. Similar improvements can be expected from decarbonation and pH control of other aqueous processing solutions. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. RP ASHBY, CIH (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 12 TC 21 Z9 21 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2147 EP 2149 DI 10.1063/1.107065 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000036 ER PT J AU HETTINGER, JD KIM, DH GRAY, KE WELP, U KAMPWIRTH, RT EDDY, M AF HETTINGER, JD KIM, DH GRAY, KE WELP, U KAMPWIRTH, RT EDDY, M TI EFFECTIVE ELECTRIC-FIELD IN DC MAGNETIZATION MEASUREMENTS - COMPARING MAGNETIZATION TO TRANSPORT CRITICAL CURRENTS SO APPLIED PHYSICS LETTERS LA English DT Article ID BA-CU-O; YBA2CU3O7-DELTA SINGLE-CRYSTALS; SUPERCONDUCTORS; FILMS AB We report values of critical current (J(c)) for Tl2Ba2CaCu2Ox(Tl-2212) epitaxial thin films in magnetic fields up to 5 T and at temperatures of 5, 40, and 77 K determined from dc magnetization and using a standard transport technique. Although we verify the applicability of Bean's model [Rev. Mod. Phys. 36, 31 (1964)], these values only agree at small applied magnetic fields and at low temperatures. Our results indicate that the differences observed in J(c)'s determined from the two techniques may be understood by considering only the field-dependent, nonlinear E-J characteristic and the "effective" electric-field criterion used in determining J(c). C1 SUPERCONDUCTOR TECHNOL INC,SANTA BARBARA,CA 93111. RP HETTINGER, JD (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 14 TC 19 Z9 19 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 27 PY 1992 VL 60 IS 17 BP 2153 EP 2155 DI 10.1063/1.107067 PG 3 WC Physics, Applied SC Physics GA HQ500 UT WOS:A1992HQ50000038 ER PT J AU JONES, RAL NORTON, LJ SHULL, KR KRAMER, EJ FELCHER, GP KARIM, A FETTERS, LJ AF JONES, RAL NORTON, LJ SHULL, KR KRAMER, EJ FELCHER, GP KARIM, A FETTERS, LJ TI INTERFACIAL SEGMENT DENSITY PROFILES OF END-ANCHORED POLYMERS IN A MELT SO MACROMOLECULES LA English DT Article ID BLOCK COPOLYMERS; ADSORPTION; BLENDS; BRUSH; POLYSTYRENE AB The segment density profile of end-functionalized deuterated polystyrene (EF-dPS) polymers anchored in a surrounding melt of hydrogenated polystyrene (hPS) to an interface with silicon was determined by neutron reflectometry. Thin films of mixtures with various volume fractions of the EF-dPS and hPS were spun cast from toluene solutions onto the silicon. These films as cast were uniform as a function of depth. After heating to 184-degrees-C for approximately 1 day to allow equilibrium segregation to be achieved in the films, neutron reflection measurements were performed. The EF-dPS segment density profiles phi(z) needed to fit the reflectivity data showed a high phi at the silicon interface which increased to a maximum approximately 10 nm away from the interface and then fell monotonically to the bulk segment density phi infinity. The interface excess determined by integration of these profiles was in excellent agreement with that directly determined by forward recoil spectrometry on the same samples. The form of the profiles is consistent with the predictions of a self-consistent mean field theory if, in addition to a large attachment free energy of the end group to the silicon, there is a weak preferential attraction of the silicon for the more polarizable hPS segments relative to the less polarizable dPS segments. C1 CORNELL UNIV,DEPT MAT SCI & ENGN,ITHACA,NY 14853. CORNELL UNIV,CTR MAT SCI,ITHACA,NY 14853. UNIV CAMBRIDGE,DEPT PHYS,CAMBRIDGE CB3 0HE,ENGLAND. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. RI Shull, Kenneth/B-7536-2009; OI Jones, Richard/0000-0001-5400-6369 NR 40 TC 94 Z9 94 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 27 PY 1992 VL 25 IS 9 BP 2359 EP 2368 DI 10.1021/ma00035a012 PG 10 WC Polymer Science SC Polymer Science GA HR586 UT WOS:A1992HR58600012 ER PT J AU CHAKRABORTY, AK ADRIANI, PM AF CHAKRABORTY, AK ADRIANI, PM TI GLASSY RELAXATION AT POLYMER SOLID INTERFACES SO MACROMOLECULES LA English DT Article ID KINETIC ISING-MODEL; TRANSITION; ADHESION AB We present a kinetic Ising model for the cooperative dynamics associated with the relaxation of adsorbed polymer chains. At low temperatures, the chain molecules are frozen in nonequilibrium conformations. Over a range of temperatures the dynamics of relaxation are found to be described by stretched exponential (KWW) functions. Average relaxation times exhibit a strongly non-Arrhenius temperature dependence. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM ENGN,BERKELEY,CA 94720. RP CHAKRABORTY, AK (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720, USA. NR 24 TC 51 Z9 51 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 27 PY 1992 VL 25 IS 9 BP 2470 EP 2473 DI 10.1021/ma00035a027 PG 4 WC Polymer Science SC Polymer Science GA HR586 UT WOS:A1992HR58600027 ER PT J AU BEADLE, P ARMES, SP GOTTESFELD, S MOMBOURQUETTE, C HOULTON, R ANDREWS, WD AGNEW, SF AF BEADLE, P ARMES, SP GOTTESFELD, S MOMBOURQUETTE, C HOULTON, R ANDREWS, WD AGNEW, SF TI ELECTRICALLY CONDUCTIVE POLYANILINE COPOLYMER LATEX COMPOSITES SO MACROMOLECULES LA English DT Article ID COLLOIDAL DISPERSIONS; MAGNETIC-RESONANCE; EMERALDINE POLYMER; PARTICLES; FILMS; TRANSPORT AB We have prepared and characterized a series of polyaniline-copolymer latex composites by chemically polymerizing aniline in the presence of a film-forming chlorinated copolymer latex. The mass loading of polyaniline in the resulting macroscopic precipitates can be easily controlled by varying the initial concentration of the copolymer latex particles. These composites have been characterized in terms of their chemical composition, electrical conductivity, relative thermal stability, and morphology by elemental microanalyses, FTIR microscopy, dc conductivity measurements as a function of temperature, thermogravimetric analysis, and scanning electron microscopy, respectively. C1 UNIV SUSSEX, SCH CHEM & MOLEC SCI, BRIGHTON BN1 9QJ, E SUSSEX, ENGLAND. UNIV CALIF LOS ALAMOS SCI LAB, ELECTR RES GRP, LOS ALAMOS, NM 87545 USA. UNIV CALIF LOS ALAMOS SCI LAB, DIV ISOTOPE & NUCL CHEM, LOS ALAMOS, NM 87545 USA. OI Armes, Steven/0000-0002-8289-6351 NR 39 TC 102 Z9 103 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD APR 27 PY 1992 VL 25 IS 9 BP 2526 EP 2530 DI 10.1021/ma00035a035 PG 5 WC Polymer Science SC Polymer Science GA HR586 UT WOS:A1992HR58600035 ER PT J AU SATCHLER, GR AF SATCHLER, GR TI LOCAL POTENTIAL MODEL FOR PION-NUCLEUS SCATTERING AND PI(+)/PI(-) EXCITATION RATIOS SO NUCLEAR PHYSICS A LA English DT Article ID GIANT QUADRUPOLE-RESONANCE; COUPLED-CHANNELS CALCULATIONS; EVEN-EVEN NUCLIDES; INELASTIC-SCATTERING; ELASTIC-SCATTERING; ELECTRON-SCATTERING; COULOMB-EXCITATION; CHARGE-EXCHANGE; 3,3 RESONANCE; PB-208 AB Local potentials of Woods-Saxon shape are introduced to describe the elastic scattering of pions from the nuclei Ca-40, Ca-48, Ni-58, Zr-90, Sn-118 and Pb-208 at energies in the 100-300 MeV range. Good fits to the measurements are easily obtained and potential ambiguities are discussed. The optical potentials are then applied, using the deformed-potential prescription and independent information on B(E2) and B(E3) values, to inelastic scattering exciting the lowest 2+ and 3-collective states of these nuclei, as well as the giant quadrupole resonances. This procedure is parallel to that used in the analysis of scattering data for other hadrons. Sufficiently good agreement with experimental data is obtained to establish the validity of this approach for pions also. Remaining discrepancies are similar to those found when using a more microscopic and nonlocal approach. In particular, our semi-empirical method does not change the apparently anomalous M(n)/M(p) ratios for the giant resonances deduced from comparisons of pi+ and pi--scattering. These discrepancies are discussed in detail, and in relation to results obtained using other hadronic probes. We suggest that they arise from uncertainties in the data rather than in deficiencies in our understanding of the scattering. RP SATCHLER, GR (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 63 TC 57 Z9 57 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 27 PY 1992 VL 540 IS 3-4 BP 533 EP 576 DI 10.1016/0375-9474(92)90173-H PG 44 WC Physics, Nuclear SC Physics GA HZ335 UT WOS:A1992HZ33500007 ER PT J AU BLUDMAN, SA KENNEDY, DC LANGACKER, PG AF BLUDMAN, SA KENNEDY, DC LANGACKER, PG TI SEESAW MODEL SOLUTIONS OF THE SOLAR NEUTRINO PROBLEM SO NUCLEAR PHYSICS B LA English DT Article ID LEPTON NUMBER; MAJORANA NEUTRINOS; HEAVY NEUTRINOS; BETA-DECAY; OSCILLATIONS; MATTER; MASSES; VIOLATION; BARYON; LIMITS AB We re-examine solutions to the solar neutrino problem involving neutrino oscillations, decaying neutrinos and a cooler center of the sun. Comparison of the Homestake and Kamiokande II observations implies that low-energy neutrinos are more suppressed than high-energy, disfavoring the large-mass adiabatic MSW resonance and allowing us to exclude non-standard solar models with a simple reduction of core temperature. Diagonal (sin(2)2-theta congruent-to 0.004-0.5, DELTA-m2 congruent-to 0.08-10 meV2), vertical large-angle (sin2 congruent-to 0.6-0.9, DELTA-m2 congruent-to 0.08-2, 4-60 meV2), and part of the horizontal (sin(2)2-theta congruent-to 0.02-0.6, DELTA-m2 congruent-to 80 meV2) MSW solutions are compatible with these data (meV = 10(-3) eV). The present SAGE results disfavor non-standard solar models and the horizontal MSW solution. Assuming nu(e) --> nu(mu) conversion, we show that seesaw models of neutrino masses imply m(nu(mu)) = 0.3-9 meV, intermediate-scale symmetry breaking O(10(9)-10(12)) GeV, and a tau-neutrino mass with cosmological ramifications in some cases and laboratory or atmospheric nu(mu)-nu(tau) oscillations. While seesaw predictions for neutrino masses are model-dependent and subject to large uncertainties, we prove that leptonic mixing angles are similar to quark mixings for a wide range of models. We also present two specific seesaw models compatible with electroweak neutral current and proton decay constraints, including radiative corrections to the seesaw predictions. C1 UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP BLUDMAN, SA (reprint author), UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720, USA. NR 83 TC 56 Z9 56 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 27 PY 1992 VL 374 IS 2 BP 373 EP 391 DI 10.1016/0550-3213(92)90358-I PG 19 WC Physics, Particles & Fields SC Physics GA HR445 UT WOS:A1992HR44500007 ER PT J AU WATKINS, R WIDROW, LM AF WATKINS, R WIDROW, LM TI ASPECTS OF REHEATING IN 1ST-ORDER INFLATION SO NUCLEAR PHYSICS B LA English DT Article ID EXTENDED INFLATION; CHAOTIC INFLATION; SYMMETRY-BREAKING; UNIVERSE; COSMOLOGY; VACUUM AB We study reheating in theories where inflation is completed by a first-order phase transition. In these scenarios, the Universe decays from its false vacuum state by bubble nucleation. We follow the Universe through the phase transition beginning with bubble nucleation and ending with particle production from wall collisions. In the first stage of reheating. vacuum energy is converted into kinetic energy for the bubble walls. To help understand this phase we derive a simple expression for the equation of state of a universe filled with expanding bubbles. Eventually the bubble walls collide. The production of particles during wall collisions from both classical and quantum processes is examined. We study classical scalar wave production through numerical simulations of two-bubble collisions, clarifying and extending previous work by Hawking, Moss and Stewart. We go on to discuss direct quantum particle production due to couplings between the inflation and other fields. We calculate particle production for colliding walls in both sine-Gordon and phi-4 theories. Our results indicate that both classical and quantum processes are quite efficient for models with double-well potentials, but can be suppressed for models with potentials that are periodic. In addition, we show that particles with masses well above the mass of the inflation can be produced if the walls are highly relativistic. The relevance of our work for recently proposed models of first-order inflation is discussed. C1 FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV TORONTO,CANADIAN INST THEORET ASTROPHYS,TORONTO M5S 1A1,ONTARIO,CANADA. RP WATKINS, R (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, 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 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 27 PY 1992 VL 374 IS 2 BP 446 EP 468 DI 10.1016/0550-3213(92)90362-F PG 23 WC Physics, Particles & Fields SC Physics GA HR445 UT WOS:A1992HR44500011 ER PT J AU DODELSON, S FRIEMAN, JA TURNER, MS AF DODELSON, S FRIEMAN, JA TURNER, MS TI CONSTRAINTS TO THE DECAYS OF DIRAC NEUTRINOS FROM SN-1987A SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERNOVA 1987A; BETA-SPECTRUM; 17-KEV NEUTRINO; SN1987A; MASSES; BOUNDS; LIMITS; BURST; S-35 AB The wrong-helicity states of keV-mass Dirac neutrinos are emitted copiously from the cores of newly born neutron stars, including that associated with SN 1987A. If they decay into proper-helicity neutrinos-v(e), v(mu), or v(e)BAR, or v(mu)BAR-they should have produced distinctive high-energy events in the Kamiokande II and Irvine-Michigan-Brookhaven detectors. The absence of such events excludes these decay modes for a Dirac neutrino of mass between order 1 and 300 keV and lifetime 10(-9)[m(v)/(1 keV)] sec less than or similar to tau less than or similar to 5 x 10(7)[m(v)/(1 keV)] sec. This places severe constraints on models for Simpson's 17-keV neutrino. C1 UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. RP DODELSON, S (reprint author), FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 39 TC 18 Z9 18 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2572 EP 2575 DI 10.1103/PhysRevLett.68.2572 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000002 ER PT J AU SOMALWAR, SV BARKER, A BRIERE, RA GIBBONS, LK MAKOFF, G PAPADIMITRIOU, V PATTERSON, JR WAH, YW WINSTEIN, B WINSTON, R YAMAMOTO, H SWALLOW, EC BOCK, GJ COLEMAN, R ENAGONIO, J HSIUNG, YB RAMBERG, E STANFIELD, K TSCHIRHART, R YAMANAKA, T GOLLIN, GD KARLSSON, M OKAMITSU, JK DEBU, P PEYAUD, B TURLAY, R VALLAGE, B AF SOMALWAR, SV BARKER, A BRIERE, RA GIBBONS, LK MAKOFF, G PAPADIMITRIOU, V PATTERSON, JR WAH, YW WINSTEIN, B WINSTON, R YAMAMOTO, H SWALLOW, EC BOCK, GJ COLEMAN, R ENAGONIO, J HSIUNG, YB RAMBERG, E STANFIELD, K TSCHIRHART, R YAMANAKA, T GOLLIN, GD KARLSSON, M OKAMITSU, JK DEBU, P PEYAUD, B TURLAY, R VALLAGE, B TI MEASUREMENT OF THE QUADRATIC SLOPE PARAMETER IN THE K(L)-]3-PI-0 DECAY DALITZ PLOT SO PHYSICAL REVIEW LETTERS LA English DT Article AB We report a value of -[3.3 +/- 1.1 (stat) +/- 0.7(syst)] x 10(-3) for the quadratic slope parameter h in the Dalitz plot of the K(L) --> 3-pi-0 decay. This result is obtained from a sample of 5.1 X 10(6) decays. The validity of the DELTA-I = 1/2 rule in the quadratic term is investigated using this result. This is the first measurement of the 3-pi-0 slope parameter, and also the most sensitive measurement of any of the quadratic slope parameters for the charged or neutral kaons. C1 ELMHURST COLL,DEPT PHYS,ELMHURST,IL 60126. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. CENS,DEPT PHYS,F-91190 GIF SUR YVETTE,FRANCE. RP SOMALWAR, SV (reprint author), UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637, USA. RI Briere, Roy/N-7819-2014 OI Briere, Roy/0000-0001-5229-1039 NR 9 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2580 EP 2583 DI 10.1103/PhysRevLett.68.2580 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000004 ER PT J AU ALVERSON, G BAKER, WF BALLOCCHI, G BENSON, R BERG, D BLUSK, S BROMBERG, C BROWN, D CAREY, D CHAND, T CHANDLEE, C CHOUDHARY, BC CHUNG, WH DEBARBARO, L DESOI, W DLUGOSZ, W DUNLEA, J EASO, S ENGELS, E FAISSLER, W FANOURAKIS, G FERBEL, T GARELICK, D GINTHER, G GLASS, G GLAUBMAN, M GUTIERREZ, P HARTMAN, K HUSTON, J JOHNSTONE, C KAPOOR, V KOURBANIS, I LANARO, A LIRAKIS, C LOBKOWICZ, F LUKENS, P MANI, S MAUL, A MANSOUR, J MILLER, R NELSON, CA OH, B ORRIS, D POTHIER, E PREBYS, E RAJARAM, BM ROSER, R RUDDICK, K SHEPARD, P SHIVPURI, RK SINANIDIS, A SKOW, D SLATTERY, P SORRELL, L TOOTHACKER, W VARELAS, N WEERASUNDARA, D WHITMORE, J WU, G YASUDA, T YOSEF, C ZIELINSKI, M AF ALVERSON, G BAKER, WF BALLOCCHI, G BENSON, R BERG, D BLUSK, S BROMBERG, C BROWN, D CAREY, D CHAND, T CHANDLEE, C CHOUDHARY, BC CHUNG, WH DEBARBARO, L DESOI, W DLUGOSZ, W DUNLEA, J EASO, S ENGELS, E FAISSLER, W FANOURAKIS, G FERBEL, T GARELICK, D GINTHER, G GLASS, G GLAUBMAN, M GUTIERREZ, P HARTMAN, K HUSTON, J JOHNSTONE, C KAPOOR, V KOURBANIS, I LANARO, A LIRAKIS, C LOBKOWICZ, F LUKENS, P MANI, S MAUL, A MANSOUR, J MILLER, R NELSON, CA OH, B ORRIS, D POTHIER, E PREBYS, E RAJARAM, BM ROSER, R RUDDICK, K SHEPARD, P SHIVPURI, RK SINANIDIS, A SKOW, D SLATTERY, P SORRELL, L TOOTHACKER, W VARELAS, N WEERASUNDARA, D WHITMORE, J WU, G YASUDA, T YOSEF, C ZIELINSKI, M TI DIRECT PHOTON PRODUCTION AT HIGH P(T) IN PI -BE AND PBE COLLISIONS AT 500 GEV/C SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSVERSE-MOMENTUM; 280 GEV/C; PP INTERACTIONS; ETA-PRODUCTION; GLUON CONTENT; PROTONS; PIONS; ORDER; REAL; QCD AB We report new measurements of inclusive direct photon production at high transverse momenta (p(T)) for pi- and p-interactions on Be at 500 Gev/c. The yields as a function Of p(T) and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions. C1 UNIV DELHI,DELHI 110007,INDIA. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. NORTHEASTERN UNIV,BOSTON,MA 02115. UNIV OKLAHOMA,NORMAN,OK 73019. PENN STATE UNIV,UNIV PK,PA 16802. UNIV PITTSBURGH,PITTSBURGH,PA 15260. UNIV ROCHESTER,ROCHESTER,NY 14627. RP ALVERSON, G (reprint author), UNIV CALIF DAVIS,DAVIS,CA 95616, USA. RI Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011 NR 18 TC 16 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2584 EP 2587 DI 10.1103/PhysRevLett.68.2584 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000005 ER PT J AU LURIO, LB RABEDEAU, TA PERSHAN, PS SILVERA, IF DEUTSCH, M KOSOWSKY, SD OCKO, BM AF LURIO, LB RABEDEAU, TA PERSHAN, PS SILVERA, IF DEUTSCH, M KOSOWSKY, SD OCKO, BM TI LIQUID-VAPOR DENSITY PROFILE OF HELIUM - AN X-RAY STUDY SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE; HE-4; SILICON; FILMS AB The average liquid-vapor density profiles [rho(z)] of thick He-4 films adsorbed onto a silicon substrate were measured using x-ray reflectivity. The results are well represented by a 90%-10% interfacial width of 9.2 +/- 1 angstrom at 1.13 K which extrapolates to a T = 0 K, 90%-10% interfacial width of 7.6(-2)+1 angstrom. The sensitivity of the measurement to the width, shape, and asymmetry of the density profile is discussed. C1 BAR ILAN UNIV,DEPT PHYS,IL-52100 RAMAT GAN,ISRAEL. HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP LURIO, LB (reprint author), HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138, USA. NR 25 TC 66 Z9 66 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2628 EP 2631 DI 10.1103/PhysRevLett.68.2628 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000016 ER PT J AU DAVIS, HL HANNON, JB RAY, KB PLUMMER, EW AF DAVIS, HL HANNON, JB RAY, KB PLUMMER, EW TI ANOMALOUS INTERPLANAR EXPANSION AT THE (0001) SURFACE OF BE SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE-RELAXATION; METAL-SURFACES; MULTILAYER RELAXATION; ELECTRONIC-STRUCTURE; BERYLLIUM; DENSITY; ENERGY; MONOLAYERS; AL(100) AB Analysis of low-energy electron diffraction spectra for Be(0001) shows that the interplanar spacing between the first and second planes is expanded by 5.8% or 0.10 angstrom. The size of this expansion is large compared to that of close-packed fcc (111) surfaces, which show little or no expansion. This large expansion is discussed in terms of the unique bonding of Be. The second and third interplanar spacings show almost no relaxation. C1 UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. RP DAVIS, HL (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 27 TC 119 Z9 119 U1 2 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2632 EP 2635 DI 10.1103/PhysRevLett.68.2632 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000017 ER PT J AU BORING, AM ALBERS, RC ERIKSSON, O KOELLING, DD AF BORING, AM ALBERS, RC ERIKSSON, O KOELLING, DD TI HUBBARD PARAMETERS FOR METALLIC CE SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE; VOLUME COLLAPSE; ALPHA-CERIUM; GROUND-STATE; TRANSITION; PHOTOEMISSION AB We have obtained a phase diagram of the alpha --> gamma-transition (moment formation) as a function of the U and J Kanamori Hubbard parameters. Overlap and hybridization terms are obtained by a tight-binding fit to first-principles band calculations. At the one-electron level we obtain no fundamental change in the interaction energies in going through the alpha --> gamma-transition region. This is the first model to obtain self-consistent values for the Hubbard parameters in the solid state and they are in reasonable agreement with the experimentally derived values. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. ARGONNE NATL LAB,ARGONNE,IL 60439. RP BORING, AM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 29 TC 23 Z9 23 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2652 EP 2655 DI 10.1103/PhysRevLett.68.2652 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000022 ER PT J AU RAMIREZ, AP COLEMAN, P CHANDRA, P BRUCK, E MENOVSKY, AA FISK, Z BUCHER, E AF RAMIREZ, AP COLEMAN, P CHANDRA, P BRUCK, E MENOVSKY, AA FISK, Z BUCHER, E TI NONLINEAR SUSCEPTIBILITY AS A PROBE OF TENSOR SPIN ORDER IN URU2SI2 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON SUPERCONDUCTOR URU2SI2; FERMION SYSTEM URU2SI2; PHASE-TRANSITIONS; MAGNETIC ORDER; RESISTIVITY; SURFACE; GLASSES; UPT3; UPD3 AB The nonlinear susceptibility is discussed as a probe of multispin correlation functions. In the heavy-fermion compound URu2Si2, measurements of the leading nonlinear susceptibility (chi-3) reveal a sharp anomaly at 17.3 K closely matching that of the specific heat at the same temperature. We attribute this result to the development of anisotropic triplet pairing in the particle-hole channel of the heavy electron fluid. C1 RUTGERS STATE UNIV,SERIN PHYS LAB,PISCATAWAY,NJ 08854. NEC CORP LTD,RES INST,PRINCETON,NJ 08540. UNIV AMSTERDAM,NATUURKUNDIG LAB,1018 XE AMSTERDAM,NETHERLANDS. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CONSTANCE,W-7750 CONSTANCE,GERMANY. RP RAMIREZ, AP (reprint author), AT&T BELL LABS,600 MTN AVE,MURRAY HILL,NJ 07974, USA. RI Bruck, Ekkes/E-3365-2014 NR 37 TC 102 Z9 102 U1 1 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2680 EP 2683 DI 10.1103/PhysRevLett.68.2680 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000029 ER PT J AU GARCIA, AE AF GARCIA, AE TI LARGE-AMPLITUDE NONLINEAR MOTIONS IN PROTEINS SO PHYSICAL REVIEW LETTERS LA English DT Article ID HYDROPHOBIC PROTEIN; CRAMBIN; DYNAMICS; SIMULATION; MOLECULES; STATES; WATER AB A molecular-dynamics calculation on a hydrated protein, crambin, demonstrates that (i) neighboring dihedral angles are correlated to local transitions in the protein backbone, and that (ii) the amplitude of collective excitations, representing correlated global motions in the protein, samples multicentered distributions. The time dependence of the multicentered dihedral and collective excitations show rapid transitions from the center of one distribution to another, followed for some time by damped, low-amplitude motions around one center. The global nonlinear collective excitations are responsible for most of the atomic fluctuations of the molecule. An analysis appropriate to multimodal conformations is reported. RP GARCIA, AE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,THEORET BIOL & BIOPHYS GRP,LOS ALAMOS,NM 87545, USA. NR 27 TC 548 Z9 556 U1 2 U2 43 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2696 EP 2699 DI 10.1103/PhysRevLett.68.2696 PG 4 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000033 ER PT J AU VINOKUR, V GESHKENBEIN, V AF VINOKUR, V GESHKENBEIN, V TI EXACT SOLUTION FOR FLUX CREEP WITH LOGARITHMIC U(J) DEPENDENCE - SELF-ORGANIZED CRITICAL STATE IN HIGH-TC SUPERCONDUCTORS - REPLY SO PHYSICAL REVIEW LETTERS LA English DT Letter RP VINOKUR, V (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 4 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 27 PY 1992 VL 68 IS 17 BP 2707 EP 2707 DI 10.1103/PhysRevLett.68.2707 PG 1 WC Physics, Multidisciplinary SC Physics GA HQ440 UT WOS:A1992HQ44000040 ER PT J AU DIETZ, ML AF DIETZ, ML TI GAY SCIENTISTS SO SCIENTIST LA English DT Letter RP DIETZ, ML (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 1 TC 0 Z9 0 U1 1 U2 5 PU SCIENTIST INC PI PHILADELPHIA PA 3600 MARKET ST SUITE 450, PHILADELPHIA, PA 19104 SN 0890-3670 J9 SCIENTIST JI Scientist PD APR 27 PY 1992 VL 6 IS 9 BP 12 EP 12 PG 1 WC Information Science & Library Science; Multidisciplinary Sciences SC Information Science & Library Science; Science & Technology - Other Topics GA HP778 UT WOS:A1992HP77800011 ER PT J AU SCOTT, CD AF SCOTT, CD TI REMOVAL OF DISSOLVED METALS BY PLANT-TISSUE SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Note DE STRONTIUM; ADSORPTION; PLANT TISSUE; LYCOPERSICON-ESCULENTUM; NICOTIANA-TABACUM ID CADMIUM AB Various types of microbial biomass have been shown to adsorb metals dissolved in aqueous media. It has now been demonstrated that certain plant tissues are also effective for this type of adsorption process. In particular, tomato and tobacco roots harvested from field-grown plants were shown to adsorb Sr from an aqueous solution of SrCl2. Distribution coefficients in excess of 550 were measured and the adsorption isotherms at 25-degrees-C could be fitted to Langmuir-type expressions. The bioadsorbent could be regenerated and metals recovered by either a reduction in the pH to less than 2.0 or by use of a concentrated chloride salt solution. RP SCOTT, CD (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 12 TC 45 Z9 45 U1 2 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD APR 25 PY 1992 VL 39 IS 10 BP 1064 EP 1068 DI 10.1002/bit.260391011 PG 5 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA HM254 UT WOS:A1992HM25400010 PM 18600906 ER PT J AU SOPER, TS LARIMER, FW MURAL, RJ LEE, EH HARTMAN, FC AF SOPER, TS LARIMER, FW MURAL, RJ LEE, EH HARTMAN, FC TI ROLE OF ASPARAGINE-111 AT THE ACTIVE-SITE OF RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE FROM RHODOSPIRILLUM-RUBRUM AS EXPLORED BY SITE-DIRECTED MUTAGENESIS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID RIBULOSE-BISPHOSPHATE CARBOXYLASE; RIBULOSEBISPHOSPHATE CARBOXYLASE; 1,5-BISPHOSPHATE CARBOXYLASE; SUBUNIT INTERACTIONS; MUTANTS; ENZYME; HYBRIDIZATION; RESOLUTION AB Crystallographic studies of ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum suggest that active-site Asn111 interacts with Mg2+ and/or substrate (Lundqvist, T., and Schneider, G. (1991) J. Biol. Chem. 266, 12604-12611). To examine possible catalytic roles of Asn111, we have used site-directed mutagenesis to replace it with a glutaminyl, aspartyl, seryl, or lysyl residue. Although the mutant proteins are devoid of detectable carboxylase activity, their ability to form a quaternary complex comprised of CO2, Mg2+, and a reaction-intermediate analogue is indicative of competence in activation chemistry and substrate binding. The mutant proteins retain enolization activity, as measured by exchange of the C3 proton of ribulose bisphosphate with solvent, thereby demonstrating a preferential role of Asn111 in some later step of overall catalysis. The active sites of this homodimeric enzyme are formed by interactive domains from adjacent subunits (Larimer, F. W., Lee, E. H., Mural, R. J., Soper, T. S., and Hartman, F. C. (1987) J. Biol. Chem. 262, 15327-15329). Crystallography assigns Asn111 to the aminoterminal domain of the active site (Knight, S., Andersson, I., and Branden, C.-I. (1990) J. Mol. Biol. 215, 113-160). The observed formation of enzymatically active heterodimers by the in vivo hybridization of an inactive position-111 mutant with inactive carboxyl-terminal domain mutants is consistent with this assignment. RP SOPER, TS (reprint author), OAK RIDGE NATL LAB,DIV BIOL,PROT ENGN & MOLEC MUTAGENESIS PROGRAM,OAK RIDGE,TN 37831, USA. NR 37 TC 13 Z9 13 U1 3 U2 7 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 25 PY 1992 VL 267 IS 12 BP 8452 EP 8457 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA HQ185 UT WOS:A1992HQ18500076 PM 1569095 ER PT J AU MEIJER, G CHANDLER, DW AF MEIJER, G CHANDLER, DW TI DEGENERATE 4-WAVE-MIXING ON WEAK TRANSITIONS IN THE GAS-PHASE USING A TUNABLE EXCIMER LASER SO CHEMICAL PHYSICS LETTERS LA English DT Article ID STATE-SELECTIVE DETECTION; GRATING EXPERIMENTS; OPTICAL PROCESSES; DYNAMICS; OH; MOLECULES; FLAMES AB A simple degenerate four-wave mixing apparatus with a forward-geometry (DFWM-FG) is used to monitor weak absorptions of stable molecules in the gas phase. We demonstrate that DFWM-FG with a tunable ArF excimer laser enables the detection of H-2 via the two-photon allowed E,F 1-SIGMA(g)+, v' <-- X 1-SIGMA(g)+, v" = 0 transition and the detection of CO via the spin-forbidden a 3-PI, v' = 2 <-- X 1-SIGMA+, v" = 0 transition. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94550. RP MEIJER, G (reprint author), CATHOLIC UNIV NIJMEGEN,DEPT MOLEC & LASER PHYS,TOERNOOIVELD,6525 ED NIJMEGEN,NETHERLANDS. RI Meijer, Gerard/D-2141-2009 NR 22 TC 25 Z9 26 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 24 PY 1992 VL 192 IS 1 BP 1 EP 4 DI 10.1016/0009-2614(92)85418-A PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR944 UT WOS:A1992HR94400001 ER PT J AU KLOTS, CE AF KLOTS, CE TI STERIC FACTORS FOR BIMOLECULAR REACTIONS SO CHEMICAL PHYSICS LETTERS LA English DT Article AB A simple model for the steric factor in bimolecular reactions is developed. The assumptions are identified which underlie an earlier result of Pelzer and Wigner and of Johnston, when one of the reagents is an atom. The treatment is then extended to reactions between two molecules. In each case it is found that, as extraneous material is added to the molecular reagents, the steric factor will decrease but the pre-exponential factor will tend to remain constant. Contact is then made with analogous results from the statistical adiabatic model. RP KLOTS, CE (reprint author), OAK RIDGE NATL LAB,CHEM PHYS SECT,OAK RIDGE,TN 37831, USA. NR 8 TC 1 Z9 1 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 APR 24 PY 1992 VL 192 IS 1 BP 41 EP 44 DI 10.1016/0009-2614(92)85424-9 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR944 UT WOS:A1992HR94400007 ER PT J AU ZHENG, Y HUSSAIN, Z SHIRLEY, DA AF ZHENG, Y HUSSAIN, Z SHIRLEY, DA TI AMPLITUDES AND PHASE-SHIFTS IN ELECTRON ATOM FORWARD SCATTERING - STRONG DEPENDENCE ON ATOMIC VALENCE-ELECTRONS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ABSORPTION FINE-STRUCTURE; EXTENDED X-RAY; PHOTOELECTRON DIFFRACTION; RESOLVED PHOTOEMISSION; STRUCTURE SPECTROSCOPY; ABINITIO CALCULATIONS; HOLOGRAPHY; SOLIDS; CO AB Forward-scattering amplitudes and phase shifts for intermediate-energy electrons were systematically calculated for selected elements throughout the periodic table. Characteristic variations in the forward-scattering amplitudes with atomic number were found, which differ from those observed in back-scattering amplitudes. Strong effects of atomic valence electrons on the forward-scattering process are evident. RP ZHENG, Y (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,MS2-300,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 22 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 24 PY 1992 VL 192 IS 1 BP 108 EP 112 DI 10.1016/0009-2614(92)85436-E PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR944 UT WOS:A1992HR94400019 ER PT J AU KNICKELBEIN, MB AF KNICKELBEIN, MB TI ELECTRONIC SHELL STRUCTURE IN THE IONIZATION-POTENTIALS OF COPPER CLUSTERS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID METAL-CLUSTERS; POTASSIUM CLUSTERS; MASS DISTRIBUTIONS; PHOTOIONIZATION; PARTICLES; SILVER; MODEL; GOLD AB The ionization potentials (IPs) of copper clusters (Cu(n)) up to 150 atoms have been bracketed using laser photoionization. Large decreases in IP at n = 2, 8, 20. 30, 34, 40 and 60 atoms are observed, as well as a strong odd-even alternation extending beyond 100 atoms. These features correspond to electronic shell and subshell closings predicted for systems of n valence electrons confined to spherical or spheroidal potentials. The decreases in IP expected to accompany shell closings at n = 58 and 92 are absent, however, and a new set of local extrema are observed, including local maxima at n = 57 and 88-91 and minima at n = 49 and 92. The possibility of perturbations to the electronic energy level structure due to geometric packing constraints is discussed. RP KNICKELBEIN, MB (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 26 TC 132 Z9 137 U1 1 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 24 PY 1992 VL 192 IS 1 BP 129 EP 134 DI 10.1016/0009-2614(92)85440-L PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HR944 UT WOS:A1992HR94400023 ER PT J AU LEE, CE AF LEE, CE TI PERFECT Q-ARY SEQUENCES FROM MULTIPLICATIVE CHARACTERS OVER GF(P) SO ELECTRONICS LETTERS LA English DT Article DE BINARY SEQUENCES; CODES AND CODING AB A new coding rule based on multiplicative characteristics over GF (p) is identified for the construction of perfect q-ary sequences. A subset of these sequences achieves the maximum possible efficiency less than unity. The new coding rule is illustrated by demonstrating that the perfect ternary Ipatov sequences are incorporated in these perfect q-ary sequences. RP LEE, CE (reprint author), SANDIA NATL LABS,EXPLORATORY SYST DEV,DIV 1,ALBUQUERQUE,NM 87185, USA. NR 9 TC 23 Z9 25 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD APR 23 PY 1992 VL 28 IS 9 BP 833 EP 835 DI 10.1049/el:19920527 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA HR784 UT WOS:A1992HR78400016 ER PT J AU WALLACE, DWR WIRICK, CD AF WALLACE, DWR WIRICK, CD TI LARGE AIR SEA GAS FLUXES ASSOCIATED WITH BREAKING WAVES SO NATURE LA English DT Article ID EXCHANGE; OCEAN; OXYGEN; WATER; INTERFACE; RATES AB THE exchange of gases between the ocean and the atmosphere exerts an important influence on the cycling and global budget of trace gases. Air-sea gas flux is normally parameterized as the product of a gas-transfer velocity and the air-sea concentration difference 1,2. Despite suggestions 3-8 that the parameterization might be inappropriate when air-bubble penetration occurs, this 'thin-film' model remains widely accepted 9 and is employed regularly in regional 10 and global-scale 11 models. Here we present a time series of near-surface dissolved O2 from November to March in coastal waters. The time series is punctuated by sudden large increases in dissolved O2 associated with surface wave activity. A numerical simulation including air injection by bubbles shows similar behaviour. If the observed O2 'events' reflect the air-sea O2 flux, our results imply that conventional parameterizations might seriously underestimate gas invasion of surface waters under storm conditions. Our study confirms that important questions remain concerning air-sea gas transfer at high wind speeds. RP BROOKHAVEN NATL LAB, DEPT APPL SCI, DIV OCEANOG & ATMOSPHER SCI, UPTON, NY 11973 USA. NR 21 TC 74 Z9 75 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD APR 23 PY 1992 VL 356 IS 6371 BP 694 EP 696 DI 10.1038/356694a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HQ146 UT WOS:A1992HQ14600053 ER PT J AU CLOSS, GL FORBES, MDE PIOTROWIAK, P AF CLOSS, GL FORBES, MDE PIOTROWIAK, P TI SPIN AND REACTION DYNAMICS IN FLEXIBLE POLYMETHYLENE BIRADICALS AS STUDIED BY EPR, NMR, AND OPTICAL SPECTROSCOPY AND MAGNETIC-FIELD EFFECTS - MEASUREMENTS AND MECHANISMS OF SCALAR ELECTRON-SPIN SPIN COUPLING SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TERT-BUTYL; PIVALOYL RADICALS; REACTION-RATES; CYCLOALKANONES; SPECTRA; CHAINS; CIDNP AB A series of spectroscopic measurements on flexible polymethylene biradicals in liquid solution is reported. Time resolved electron paramagnetic resonance, chemically induced nuclear spin polarization, transient optical absorption, and external magnetic field effects on lifetimes are used to unravel the kinetics of two types of biradical, acyl-alkyl and bisalkyl, obtained from the photoinduced Norrish type I alpha-cleavage reaction of permethylated cycloalkanones. A kinetic picture for the biradical exit channels is presented which includes rate constants for spin-orbit coupling, decarbonylation, spin relaxation, and end-to-end contact of the chains. The relative merit of each of the various experimental techniques is discussed, and the close relationship between spin and chain dynamics in the biradical kinetics is clearly illustrated. Direct and indirect measurements of the singlet-triplet splitting (electronic spin-spin coupling) are made and compared for different chain lengths. The mechanism of the coupling as well as its temperature dependence is discussed in terms of through-bond and through-space models. The acyl-alkyl biradicals are shown to have kinetics dominated by spin-orbit coupling, whereas the bisalkyl biradical spectra decay on a slower time scale via spin relaxation. Optical measurement of the decarbonylation rate of the pivaloyl monoradical is also reported. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP CLOSS, GL (reprint author), UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637, USA. NR 30 TC 108 Z9 108 U1 2 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 22 PY 1992 VL 114 IS 9 BP 3285 EP 3294 DI 10.1021/ja00035a020 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA HQ814 UT WOS:A1992HQ81400020 ER PT J AU SELTZER, S AF SELTZER, S TI SOLVENT ISOTOPE EFFECTS ON RETINAL CIS-TRANS ISOMERIZATION IN THE DARK-ADAPTATION OF BACTERIORHODOPSIN SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ADAPTED BACTERIORHODOPSIN; SCHIFF-BASE; VIBRATIONAL SPECTROSCOPY; HALOBACTERIUM-HALOBIUM; PURPLE MEMBRANE; LIGHT; PHOTOCYCLE; RHODOPSIN; TYROSINE; MUTANTS AB The solvent isotope effect on the first-order rate constant for dark adaptation of bacteriorhodopsin, near neutral pH (pD), is inverse; k(D)/k(H) = 1.24. The fit of the variation of isotope effect with the atom fraction of deuterium in the solvent to the Gross-Butler equation leads to the conclusion that the proton(s) in motion is (are) less tightly bound in the reactant than in a reactive intermediate, formed prior to the rate-controlling step of cis-trans isomerization. The near-unity isotope effect on the equilibrium between the bound 13-cis- and all-trans-retinals in the dark-adapted state mixture indicates that the isotope effects on the forward and reverse rate constants for isomerization are approximately equal to each other and equal to the isotope effect on the observed rate constant for dark adaptation. The results support a previously proposed mechanism of rate-controlling Asp-212 nucleophilic catalysis of retinal cis-trans isomerization in the dark adaptation process. RP SELTZER, S (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 42 TC 9 Z9 9 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 22 PY 1992 VL 114 IS 9 BP 3516 EP 3520 DI 10.1021/ja00035a054 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA HQ814 UT WOS:A1992HQ81400054 ER PT J AU SAXTON, MJ AF SAXTON, MJ TI GAPS IN THE ERYTHROCYTE-MEMBRANE SKELETON - A STRETCHED NET MODEL SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID RED-CELL MEMBRANE; LATERAL DIFFUSION; HEREDITARY ELLIPTOCYTOSIS; MOLECULAR-BASIS; SPECTRIN; MOBILITY; SHAPE; SPHEROCYTOSIS; VESICULATION; ENDOCYTOSIS C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CHEM BIODYNAM LAB,BERKELEY,CA 94720. RP SAXTON, MJ (reprint author), UNIV CALIF DAVIS,INST THEORET DYNAM,DAVIS,CA 95616, USA. FU NIGMS NIH HHS [GM38133] NR 52 TC 10 Z9 10 U1 1 U2 1 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD APR 21 PY 1992 VL 155 IS 4 BP 517 EP 536 DI 10.1016/S0022-5193(05)80633-2 PG 20 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA HR167 UT WOS:A1992HR16700008 PM 1619964 ER PT J AU QIANG, H POLLAK, FH MAILHIOT, C PETTIT, GD WOODALL, JM AF QIANG, H POLLAK, FH MAILHIOT, C PETTIT, GD WOODALL, JM TI UNIAXIAL-STRESS STUDY OF THE QUANTUM TRANSITIONS IN A STRAINED LAYER (001) IN0.21GA0.79AS/GAAS SINGLE QUANTUM-WELL SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON MODULATED SEMICONDUCTOR STRUCTURES ( MSS-5 ) CY JUL 08-12, 1991 CL NARA, JAPAN SP YAMADA SCI FDN ID ELECTRIC-FIELD; SEMICONDUCTOR AB We have studied the effects of large, external uniaxial stress (T) along [100] and [110] on the optical properties of a strained layer (001) In0.21Ga0.79As/GaAs single quantum well (SQW). Because of the large stresses employed the observed energy shifts exhibit a nonlinear behavior due to the stress-induced coupling with the spin-orbit split band. For T parallel-to [110] the piezoelectric coupling produces an electric field along [001] which has a significant effect on both the energies and intensities of the various intersubband transitions. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP QIANG, H (reprint author), CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210, USA. NR 7 TC 17 Z9 17 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 21 PY 1992 VL 267 IS 1-3 BP 103 EP 106 DI 10.1016/0039-6028(92)91099-W PG 4 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM901 UT WOS:A1992HM90100028 ER PT J AU EBBERS, CA HAPPE, J NIELSEN, N VELSKO, SP AF EBBERS, CA HAPPE, J NIELSEN, N VELSKO, SP TI OPTICAL-ABSORPTION AT 1.06 MU-M IN HIGHLY DEUTERATED POTASSIUM DIHYDROGEN PHOSPHATE SO APPLIED OPTICS LA English DT Article DE DEUTERATED KDP; KH2PO4; OPTICAL ABSORPTION AB We have determined the relationship between residual proton (hydrogen) concentration and optical absorption at 1.06-mu-m in highly deuterated potassium dihydrogen phosphate (KDP). The proton concentration was determined by nuclear magnetic resonance (NMR) spectroscopy and the absorbance was measured by calorimetry. We obtained a hydrogen concentration dependence of 396 +/- 55 parts in 10(6) (ppm) cm-1/% hydrogen for the omicron- (ordinary-) polarized absorbance at 1.064-mu-m, and 45 +/- 7 ppm cm-1/% hydrogen for the e- (extraordinary) polarization. In addition, the KDP crystals we tested have residual (hydrogen-independent) omicron- and e-polarized absorbances of 958 +/- 228 ppm cm-1 and 343 +/- 28 ppm cm-1, respectively, whose origin is unknown. We also found that the crystal deuterium-hydrogen (D-H) ratio can be related to the D-H ratio of the growth solution by a simple ideal mixture model with a segregation coefficient of 0.684 +/- 0.044. RP EBBERS, CA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 5508,L250,LIVERMORE,CA 94550, USA. NR 11 TC 11 Z9 11 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1992 VL 31 IS 12 BP 1960 EP 1964 PG 5 WC Optics SC Optics GA HP607 UT WOS:A1992HP60700013 PM 20720844 ER PT J AU VIECELLI, JA CHAMBERS, DH KARR, TJ AF VIECELLI, JA CHAMBERS, DH KARR, TJ TI COMPUTATION OF SMALL-SCALE VELOCITY TURBULENCE AND ITS EFFECT ON OPTICAL SCINTILLATIONS AND STIMULATED THERMAL RAYLEIGH-SCATTERING SO APPLIED OPTICS LA English DT Article DE SCATTERING; SCINTILLATION; TURBULENCE ID FIELD AB Coherent high-power light beams propagating long distances through turbulent fluids are subject to many kinds of scattering effects; among these are small-scale thermal index instabilities, in which the fluid is heated by the small fraction of light that is absorbed, amplifying the pre-existing index fluctuations and producing small-angle stimulated thermal Rayleigh scattering. Turbulent velocity fluctuations can inhibit the rate of growth of these instabilities by dispersing the thermal peturbations created by the beam. Methods for computing the turbulent diffusion of the heating perturbations, compatible with fast-Fourier-transform beam propagation computations, are presented. Propagation calculations of scintillation coherence times and small-scale velocity turbulence thresholds for stimulated thermal Rayleigh scattering are included. RP VIECELLI, JA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 16 TC 0 Z9 0 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1992 VL 31 IS 12 BP 2085 EP 2094 PG 10 WC Optics SC Optics GA HP607 UT WOS:A1992HP60700032 PM 20720863 ER PT J AU ERDOGAN, T KING, O WICKS, GW HALL, DG ANDERSON, EH ROOKS, MJ AF ERDOGAN, T KING, O WICKS, GW HALL, DG ANDERSON, EH ROOKS, MJ TI CIRCULARLY SYMMETRICAL OPERATION OF A CONCENTRIC-CIRCLE-GRATING, SURFACE-EMITTING, ALGAAS/GAAS QUANTUM-WELL SEMICONDUCTOR-LASER SO APPLIED PHYSICS LETTERS LA English DT Article AB A surface-emitting semiconductor laser that utilizes a concentric-circle grating defined by electron-beam lithography is observed to oscillate in a circularly symmetric fashion. The laser emits a circularly symmetric beam with a total beam divergence of less than 1-degrees. Despite its broad-area geometry, the laser shows no evidence of filamentation. The laser maintains a relatively narrow wavelength spectrum approximately 1 angstrom in width. C1 CORNELL UNIV,NATL NANOFABRICAT FACIL,ITHACA,NY 14853. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP ERDOGAN, T (reprint author), UNIV ROCHESTER,INST OPT,ROCHESTER,NY 14627, USA. NR 11 TC 128 Z9 129 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 20 PY 1992 VL 60 IS 16 BP 1921 EP 1923 DI 10.1063/1.107151 PG 3 WC Physics, Applied SC Physics GA HP471 UT WOS:A1992HP47100001 ER PT J AU FLEETWOOD, DM REBER, RA WINOKUR, PS AF FLEETWOOD, DM REBER, RA WINOKUR, PS TI TRAPPED-HOLE ANNEALING AND ELECTRON TRAPPING IN METAL-OXIDE-SEMICONDUCTOR DEVICES SO APPLIED PHYSICS LETTERS LA English DT Article ID THERMALLY STIMULATED CURRENTS; SILICON DIOXIDE; INTERFACE TRAPS; POINT-DEFECTS; MOS DEVICES; RADIATION; CHARGE; TRANSISTORS; GENERATION; INSULATORS AB Thermally stimulated current- and capacitance-voltage techniques are combined to provide the first quantitative estimates of the contributions of trapped-hole annealing and electron trapping to oxide-trap charge neutralization in metal-oxide-semiconductor devices. For 350-nm nonradiation-hardened oxides, trapped electrons compensate approximately 15% of the radiation-induced trapped positive charge after x-ray irradiation (evidently forming dipolar defects), and approximately 65% of the trapped positive charge remaining after positive-bias annealing at 80-degrees-C. For 45-nm radiation-hardened oxides, trapped electrons compensate approximately 45% of the trapped positive charge after irradiation, and approximately 70% after annealing. Implications for models of oxide-trap-charge buildup and annealing are discussed. RP FLEETWOOD, DM (reprint author), SANDIA NATL LABS,DEPT 1332,ALBUQUERQUE,NM 87185, USA. NR 29 TC 30 Z9 30 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 20 PY 1992 VL 60 IS 16 BP 2008 EP 2010 DI 10.1063/1.107126 PG 3 WC Physics, Applied SC Physics GA HP471 UT WOS:A1992HP47100030 ER PT J AU FULLER, GM MAYLE, R MEYER, BS WILSON, JR AF FULLER, GM MAYLE, R MEYER, BS WILSON, JR TI CAN A CLOSURE MASS NEUTRINO HELP SOLVE THE SUPERNOVA SHOCK REHEATING PROBLEM SO ASTROPHYSICAL JOURNAL LA English DT Article DE ELEMENTARY PARTICLES; SHOCK WAVES; SUPERNOVAE GENERAL ID COSMOLOGICAL DARK MATTER; WEAK-INTERACTION RATES; GRAVITATIONAL COLLAPSE; STELLAR COLLAPSE; LIGHT NEUTRINOS; SOLAR NEUTRINOS; OSCILLATIONS; STARS; EQUATION; SN1987A AB We point out that a nu(mu) or nu(tau) neutrino with a cosmologically significant mass (10-100 eV) and a small mixing (vacuum mixing angle theta > 10(-4)) with a light nu(e) would result in a matter-enhanced Mikheyev-Smirnov-Wolf-enstein resonant transformation between these species in a region above the neutrino sphere but below the stalled shock during the reheating phase of a Type II supernova. The neutrino heating behind the shock is due to charged-current nu(e) and nuBAR e captures. Since the nu(mu) and nu(tau) have considerably higher average energies than do the nu(e), neutrino flavor mixing would result in higher effective nu(e) energies behind the shock and a concomitant increase in the heating rate. Our numerical calculations suggest that this effect results in a 60% increase in the supernova explosion energy, possibly helping to solve the energy problem of delayed-mechanism supernova models. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. RP FULLER, GM (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093, USA. NR 49 TC 95 Z9 95 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1992 VL 389 IS 2 BP 517 EP 526 DI 10.1086/171228 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HP119 UT WOS:A1992HP11900007 ER PT J AU BENZ, W HILLS, JG AF BENZ, W HILLS, JG TI 3-DIMENSIONAL HYDRODYNAMICAL SIMULATIONS OF COLLIDING STARS .3. COLLISIONS AND TIDAL CAPTURES OF UNEQUAL-MASS MAIN-SEQUENCE STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE CELESTIAL MECHANICS, STELLAR DYNAMICS; GLOBULAR CLUSTERS GENERAL; HYDRODYNAMICS; METHODS NUMERICAL ID STELLAR COLLISIONS; GLOBULAR CLUSTERS; BINARIES; SYSTEMS AB We used a three-dimensional smooth-particle hydrodynamics (SPH) code with 7000 particles to simulate 30 collisions between lower main-sequence (MS) stars whose masses differ by a factor of 5. We also simulated encounters with point-mass intruders to understand better how the finite radius of the intruder affects the dynamics. The two MS stars become gravitationally bound in a physical collision if their relative velocity, V, at infinity is less than a critical (dissipation) velocity, V(d). We find that V(d) decreases from 1000 km s-1 in a head-on collision to 150 km s-1 in a grazing one. If the less massive star is replaced by a point mass (e.g., a white dwarf), V(d) remains the same for grazing collisions and tidal encounters, but it drops to approximately 600 km s-1 in head-on collisions. If V > V(d), the lower mass ms star, which is the denser of the two, passes through the more massive MS star and escapes without becoming gravitationally bound to it. In collisions between two main-sequence stars, V(d) increases with V due to increased shock dissipation. In collisions between a point mass and a main-sequence star, V(d) decreases as V increases. The only dissipation in these cases is by gravitationally induced oscillations that decrease in importance as V increases. If the two MS stars coalesce in a physical collision, the denser (lower mass) MS star settles to the center of the other one. The violent mixing of the more massive star during the encounter and the settling of the low-mass star to its center should reset the nuclear clock of the coalesced star, so it contracts to the (helium-rich) MS. The fraction of the stellar mass lost in these collisions is much less than that lost in collisions between stars of equal mass and density. In particular, grazing collisions do not produce the large mass loss and accretion disks that characterize collisions between equal-mass stars. We find that tidal captures of binary stars in globular clusters can only occur in encounters in which the closest approach of the two stars to their center of mass is less than 2.0 times the sum of their radii. Coalescence of two MS stars in a globular cluster is more probable than their forming a binary by tidal capture. Tidal capture is not possible if the impact velocity at infinity exceeds 150 km s-1. Even at zero impact velocity, the coalesced star acquires a kick velocity of up to 4.5 km s-1 by asymmetric jetting during the collision. This velocity is not enough to eject the coalesced star from a globular cluster, but it largely compensates for the dynamical cooling resulting from the coalescence of the two stars. The coalescence of stars in globular clusters does not speed up the dynamical collapse of the core of the cluster. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. NR 17 TC 67 Z9 68 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1992 VL 389 IS 2 BP 546 EP 557 DI 10.1086/171230 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HP119 UT WOS:A1992HP11900009 ER PT J AU BALL, R ARENS, JF JERNIGAN, JG KETO, E MEIXNER, MM AF BALL, R ARENS, JF JERNIGAN, JG KETO, E MEIXNER, MM TI THERMAL DUST IMAGING - THE ONSET OF ASYMMETRY IN THE ULTRACOMPACT H-II REGION G5.89-0.39 SO ASTROPHYSICAL JOURNAL LA English DT Article DE DUST, EXTINCTION; H-II REGIONS; INFRARED INTERSTELLAR CONTINUUM; ISM INDIVIDUAL (G5.89-0.39); STARS FORMATION ID ACTIVE STAR FORMATION; INFRARED-EMISSION BANDS; H2O MASERS; MOLECULAR CLOUDS; IRAS SOURCES; OBJECTS; 10-MU-M; OUTFLOW; 20-MU-M; BUBBLES AB We have obtained images of the compact radio and infrared nebula G5.89-0.39 with the Berkeley/IGPP mid-infrared array camera. The images have a resolution of 1."1 and cover five wavelength bands between 8 and 13-mu-m. On the basis of the structure and spectral energy distribution, we concur with previously published assertions that G5.89-0.39 is an ultracompact H II region. The infrared emission is extended over 6" x 4".5, very similar to the object's size in published high-resolution radio continuum maps. The mid-infrared nebula is arcuate in shape, taking the form of a partial shell open to the south, unlike the radio images where the shell is complete. At our shortest wavelength the structure is sharp-edged as in the radio maps, but diffuse emission is seen at the longest wavelength. A deep silicate absorption band is the principal feature of the spectrum of the object at these wavelengths. The ratio of the 12.5 to the 8.5-mu-m surface brightness indicates a gradual cooling of the dust toward the western side of the infrared nebula, and a more abrupt temperature drop at the inner boundary of a zone of cool, diffuse emission in the southeast. The radio and infrared structure of G5.89-0.39 can be understood in the context of a previously published model in which the O star is surrounded by a dust-free cavity that is in turn embedded in a dusty molecular cloud. The ionization front is trapped in the swept-up material that lines the boundary of this cavity, and the mid-infrared emission arises from warm dust in the same location. The new element which our infrared data add to this picture is a clear indication of how the source deviates from spherical symmetry. The intensities and temperatures of the dust are well fitted by a simple model that places the star off-center in the radio shell, implying that the expansion of the ionization front has been anisotropic. Correlations between specific features in the radio and mid-infrared images suggest that the expansion has been shaped by density variations in the molecular medium surrounding the star and that, as a consequence, G5.89-0.39 may be undergoing a rapid transition from a state of approximate spherical symmetry to one of fairly irregular morphology. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. HARVARD SMITHSONIAN CTR ASTROPHYS,SMITHSONIAN ASTROPHYS OBSERV,CAMBRIDGE,MA 02138. NR 32 TC 20 Z9 20 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1992 VL 389 IS 2 BP 616 EP 627 DI 10.1086/171234 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HP119 UT WOS:A1992HP11900013 ER PT J AU BERRY, EA HUANG, LS EARNEST, TN JAP, BK AF BERRY, EA HUANG, LS EARNEST, TN JAP, BK TI X-RAY-DIFFRACTION BY CRYSTALS OF BEEF-HEART UBIQUINOL - CYTOCHROME-C OXIDOREDUCTASE SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE CYTOCHROME-C OXIDOREDUCTASE; ELECTRON TRANSPORT; MEMBRANE PROTEINS; ENZYMES; X-RAY DIFFRACTION ID COMPLEX-III; MEMBRANE; MITOCHONDRIA; REDUCTASE; PROTEINS; SUBUNITS RP BERRY, EA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720, USA. FU NCRR NIH HHS [S07RR05918-08]; NIGMS NIH HHS [GM36884] NR 25 TC 32 Z9 33 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD APR 20 PY 1992 VL 224 IS 4 BP 1161 EP 1166 DI 10.1016/0022-2836(92)90476-Z PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA HT233 UT WOS:A1992HT23300022 PM 1314906 ER PT J AU BERG, C RAAEN, S RUCKMAN, MW AF BERG, C RAAEN, S RUCKMAN, MW TI PHOTOEMISSION-STUDIES OF EU-RH AND EU-PD INTERFACES SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID SURFACE; METALS; CERIUM; STATE AB Photoemission studies using synchrotron radiation, as well as a laboratory x-ray source, have been performed on Eu/Rh and Eu/Pd overlayer systems. Europium was deposited at room temperature onto evaporated films of Rh and Pd. Substrate core level attenuation curves, as well as shifts in substrate peak positions upon Eu deposition, suggest the formation of interfacial alloys even at room temperature. Eu 4f states were studied by resonant photoemission, which showed the Eu to be divalent at the surface. Constant final state (CFS) measurements revealed the presence of trivalent Eu below the surface. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP BERG, C (reprint author), UNIV TRONDHEIM,INST FYS,N-7034 TRONDHEIM,NORWAY. OI Raaen, Steinar/0000-0001-5565-0690 NR 19 TC 2 Z9 2 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 20 PY 1992 VL 4 IS 16 BP 4213 EP 4220 DI 10.1088/0953-8984/4/16/021 PG 8 WC Physics, Condensed Matter SC Physics GA HQ151 UT WOS:A1992HQ15100021 ER PT J AU BASS, JM BLACKMAN, JA COOKE, JF AF BASS, JM BLACKMAN, JA COOKE, JF TI THE ROLE OF THE EXCHANGE MATRIX IN THE ITINERANT-ELECTRON THEORY OF FERROMAGNETISM SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID MAGNETIC EXCITATIONS; NICKEL; IRON AB For HCP cobalt the spin-wave spectrum along the c-axis has been calculated, within the theory of itinerant-electron ferromagnetism, using the most general form of the electron-electron interaction exchange matrix. An attempt has been made to determine the relative magnitudes of the matrix elements, and the sensitivity of the spin-waves to the inclusion of the various distinct types of matrix elements is described. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP BASS, JM (reprint author), UNIV READING,DEPT PHYS,POB 220,READING RG6 2AF,BERKS,ENGLAND. NR 12 TC 3 Z9 3 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 20 PY 1992 VL 4 IS 16 BP L275 EP L280 DI 10.1088/0953-8984/4/16/005 PG 6 WC Physics, Condensed Matter SC Physics GA HQ151 UT WOS:A1992HQ15100005 ER PT J AU CHRISTENSEN, K OLAMI, Z BAK, P AF CHRISTENSEN, K OLAMI, Z BAK, P TI DETERMINISTIC 1/F NOISE IN NONCONSERVATIVE MODELS OF SELF-ORGANIZED CRITICALITY SO PHYSICAL REVIEW LETTERS LA English DT Article ID SYSTEMS AB Generic, deterministic, nonconservative models displaying self-organized criticality are shown to exhibit 1/f noise. The exponent of the power spectrum depends on the level of conservation. RP CHRISTENSEN, K (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 19 TC 84 Z9 84 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 APR 20 PY 1992 VL 68 IS 16 BP 2417 EP 2420 DI 10.1103/PhysRevLett.68.2417 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100003 ER PT J AU LINK, B AF LINK, B TI DEFLAGRATION INSTABILITY IN THE QUARK-HADRON PHASE-TRANSITION SO PHYSICAL REVIEW LETTERS LA English DT Article ID PRIMORDIAL NUCLEOSYNTHESIS; EARLY UNIVERSE; BUBBLE-GROWTH; DIFFUSION AB With the aim of determining the scale of inhomogeneities produced by the transition of quarks to hadrons in the early Universe, we study the hydrodynamic stability of slow combustion (deflagration). For a front velocity-upsilon, the phase boundary is unstable on a time scale tau approximately (1/upsilon-3) fm; surface tension stabilizes bubbles below a critical size. For supercoolings implied by the bubble separations of interest for inhomogeneous nucleosynthesis (approximately 1 m), tau is much less than the duration of the phase transition. Bubble disruption could restore homogeneous nucleosynthesis. C1 UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801. RP LINK, B (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS-D436,LOS ALAMOS,NM 87545, USA. NR 22 TC 24 Z9 24 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 APR 20 PY 1992 VL 68 IS 16 BP 2425 EP 2428 DI 10.1103/PhysRevLett.68.2425 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100005 ER PT J AU AMOS, NA AVILA, C BAKER, WF BERTANI, M BLOCK, MM DIMITROYANNIS, DA EARTLY, DP ELLSWORTH, RW GIACOMELLI, G GOMEZ, B GOODMAN, JA GUSS, CM LENNOX, AJ MONDARDINI, MR NEGRET, JP OREAR, J PRUSS, SM RUBINSTEIN, R SADR, S SANABRIA, JC SHUKLA, S SPAGNOLI, M VERONESI, I ZUCCHELLI, S AF AMOS, NA AVILA, C BAKER, WF BERTANI, M BLOCK, MM DIMITROYANNIS, DA EARTLY, DP ELLSWORTH, RW GIACOMELLI, G GOMEZ, B GOODMAN, JA GUSS, CM LENNOX, AJ MONDARDINI, MR NEGRET, JP OREAR, J PRUSS, SM RUBINSTEIN, R SADR, S SANABRIA, JC SHUKLA, S SPAGNOLI, M VERONESI, I ZUCCHELLI, S TI MEASUREMENT OF RHO, THE RATIO OF THE REAL TO THE IMAGINARY PART OF THE (P)BAR-P FORWARD ELASTIC-SCATTERING AMPLITUDE, AT ROOT-S = 1.8 TEV SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOTAL CROSS-SECTION; INTERSECTING STORAGE-RINGS; ANTIPROTON-PROTON; PP; PBAR AB We have measured-rho, the ratio of the real to the imaginary part of the ppBAR forward elastic-scattering amplitude, at square-root s = 1.8 TeV. Our result, rho = 0.140 +/- 0.069, is compared with extrapolations from lower-energy data based on dispersion relations, and with the UA4 value at square-root s = 546 GeV. C1 UNIV BOLOGNA,I-40126 BOLOGNA,ITALY. CORNELL UNIV,ITHACA,NY 14853. IST NAZL FIS NUCL,BOLOGNA,ITALY. UNIV MARYLAND,COLLEGE PK,MD 20742. GEORGE MASON UNIV,FAIRFAX,VA 22030. RP AMOS, NA (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 23 TC 132 Z9 132 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 20 PY 1992 VL 68 IS 16 BP 2433 EP 2436 DI 10.1103/PhysRevLett.68.2433 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100007 ER PT J AU GEHLSEN, MD ROSEDALE, JH BATES, FS WIGNALL, GD HANSEN, L ALMDAL, K AF GEHLSEN, MD ROSEDALE, JH BATES, FS WIGNALL, GD HANSEN, L ALMDAL, K TI MOLECULAR-WEIGHT SCALING IN CRITICAL POLYMER MIXTURES SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANGLE NEUTRON-SCATTERING; CRITICAL-BEHAVIOR; THERMODYNAMICS; BLENDS AB Symmetric binary mixtures of partially deuterated polymers were prepared at the critical composition. The segment-segment interaction energy parameter chi(eff) was varied by adjusting the difference in deuterium content DELTA-X(D) between species. Chi(eff) was measured as a function of temperature, DELTA-X(D), and molecular weight by small-angle neutron scattering. The critical point for demixing was determined to scale as chi(eff,c) is similar to N(-delta) with delta = 1.01 +/- 0.05, where N is the degree of polymerization. This result confirms the mean-field prediction of Flory and Huggins. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RISO NATL LAB,DK-4000 ROSKILDE,DENMARK. RP GEHLSEN, MD (reprint author), UNIV MINNESOTA,DEPT CHEM ENGN & MAT SCI,MINNEAPOLIS,MN 55455, USA. OI Wignall, George/0000-0002-3876-3244; Bates, Frank/0000-0003-3977-1278; Almdal, Kristoffer/0000-0002-5490-9303 NR 21 TC 95 Z9 96 U1 0 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 APR 20 PY 1992 VL 68 IS 16 BP 2452 EP 2455 DI 10.1103/PhysRevLett.68.2452 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100012 ER PT J AU ITCHKAWITZ, BS BADDORF, AP DAVIS, HL PLUMMER, EW AF ITCHKAWITZ, BS BADDORF, AP DAVIS, HL PLUMMER, EW TI SHEAR DISPLACEMENT OF THE K(110) SURFACE SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSFORMATION; HIGH-PRESSURE; POTASSIUM; TRANSITION; LEED; DIFFRACTION; LITHIUM; W(110); SODIUM; METALS AB A low-energy electron diffraction analysis of the clean K(110) surface has been performed at 25 K, providing a quantitative structural determination of a clean alkali-metal surface. The K(110) surface exhibits a novel surface phase consisting of a lateral shear displacement between the first two surface planes while preserving their two-dimensional periodicity. The atomistic description of this surface structure is related to that of the bulk martensitic phase transitions of the alkali metals. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP ITCHKAWITZ, BS (reprint author), UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104, USA. RI Baddorf, Arthur/I-1308-2016 OI Baddorf, Arthur/0000-0001-7023-2382 NR 28 TC 15 Z9 15 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 20 PY 1992 VL 68 IS 16 BP 2488 EP 2491 DI 10.1103/PhysRevLett.68.2488 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100021 ER PT J AU CHAU, LL HUANG, DW YU, Y AF CHAU, LL HUANG, DW YU, Y TI SYMMETRIES OF THE LARGE-U HUBBARD-MODEL AT HALF FILLING SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTIVITY; MEAN-FIELD-THEORY; VALENCE BOND STATE; ANTIFERROMAGNET; MECHANISM; LIMIT AB Symmetries of the Hubbard model in the large-U limit are discussed. We show that the global SU(2) symmetry of the full even-lattice Hubbard model generated by Yang's eta-pairing operators becomes a local symmetry in the large-U limit and is applicable to even-odd mixed lattices. This extends the well-known SU(2) local symmetry of Anderson, for which we construct the generators. The associated local gauge theory of the extended symmetry can be similarly formulated and has interesting physical implications: new mean-field theories with parity-changed pairings. We point out the importance of searching for the parity-dependent Aharonov-Bohm-type of effects related to these local gauge symmetries. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. ACAD SINICA,INST THEORET PHYS,BEIJING 100080,PEOPLES R CHINA. RP CHAU, LL (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. NR 23 TC 3 Z9 3 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 20 PY 1992 VL 68 IS 16 BP 2539 EP 2542 DI 10.1103/PhysRevLett.68.2539 PG 4 WC Physics, Multidisciplinary SC Physics GA HP801 UT WOS:A1992HP80100034 ER PT J AU ARONOV, IE BOGACHEK, EN KRIVE, IV AF ARONOV, IE BOGACHEK, EN KRIVE, IV TI AHARONOV-BOHM EFFECT IN A MESOSCOPIC METALLIC RING WITH A MICROWAVE INDUCED SUPERSTRUCTURE SO PHYSICS LETTERS A LA English DT Article ID QUANTUM COHERENCE; SYSTEMS AB Aharonov-Bohm oscillations in a mesoscopic metallic ring exposed to a microwave electromagnetic field are considered. It is shown that the oscillation amplitude decreases periodically with the radiation intensity. C1 ACAD SCI UKSSR,INST LOW TEMP PHYS & ENGN,KHARKOV 310164,UKRAINE,USSR. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. ACAD SCI UKSSR,INST LOW TEMP PHYS & ENGN,KHARKOV 310164,UKRAINE,USSR. RP ARONOV, IE (reprint author), ACAD SCI UKSSR,INST RADIOPHYS & ELECTR,KHARKOV 310085,UKRAINE,USSR. NR 21 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD APR 20 PY 1992 VL 164 IS 3-4 BP 331 EP 333 DI 10.1016/0375-9601(92)91115-8 PG 3 WC Physics, Multidisciplinary SC Physics GA HT164 UT WOS:A1992HT16400018 ER PT J AU YAO, XQ FRANZEN, HF AF YAO, XQ FRANZEN, HF TI TERNARY METAL-RICH TA-NB-S AT HIGH-TEMPERATURES SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article ID CRYSTAL-STRUCTURE AB Two new ternary metal-rich compounds, Nb21-x-TaxS8 and NbxTa2-xS, isostructural with the binary metal-rich compounds Nb21S8 and Ta2S respectively, were prepared by means of high temperature techniques in the ternary Ta-Nb-S system. Single-crystal structure refinements were carried out for crystals of Nb21-xTaxS8 (R/R(w) = O.027/0.043) and NbxTa2-xS (R/R(w) = O.040/0.043), and the compositions were determined as Nb14.8Ta6.2S9 and Nb0.20Ta1.80S respectively from the structure refinements. Stoichiometric ranges of ternary solid-solution-type metal-rich compounds found in the Ta-Nb-S system were determined. Common structural features of these metal-rich compounds are discussed. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP YAO, XQ (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 15 TC 9 Z9 9 U1 2 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 17 PY 1992 VL 182 IS 2 BP 299 EP 312 DI 10.1016/0925-8388(92)90604-8 PG 14 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA HW076 UT WOS:A1992HW07600015 ER PT J AU HASAN, A SRIVASTAVA, PC AF HASAN, A SRIVASTAVA, PC TI SYNTHESIS AND BIOLOGICAL STUDIES OF UNSATURATED ACYCLONUCLEOSIDE ANALOGS OF S-ADENOSYL-L-HOMOCYSTEINE HYDROLASE INHIBITORS SO JOURNAL OF MEDICINAL CHEMISTRY LA English DT Article ID ADENOSYLMETHIONINE-DEPENDENT METHYLTRANSFERASES; ADENOSYLHOMOCYSTEINE HYDROLASE; NEPLANOCIN-A; MOLECULAR DISSECTIONS; POTENTIAL INHIBITORS; ANTIVIRAL AGENTS; NUCLEOSIDES; MECHANISM; ALCOHOLS; CELLS AB The design, synthesis, and biological evaluation of several unsaturated acyclonucleosides related to augustmycin A are described. The (propargyloxy)methyl acyclonucleoside analogues of 6-chloropurine, adenine, 6-methoxypurine, hypoxanthine, 6-mercaptopurine, and azathioprine have been prepared. The 9-[(propargyloxy)methyl]adenine (5) and 9-[(propargyloxy)methyl]hypoxanthine (12) analogues were converted to the corresponding 5'-tributylstannyl intermediates (9 and 13), respectively, which gave 9-[[[(Z)-5-iodo-5-propenyl]oxy]methyl]adenine (10) and 9-[[[(Z)-5-iodo-5-propenyl]oxy]methyl]hypoxanthine (14), respectively, after iododestannylation. The [I-125]-radiolabeled congeners of 10 and 14 were prepared as potential metabolic markers. Among the unsaturated acyclonucleosides tested, 9-[(propargyloxy)methyl]-6-chloropurine (3), 9-[(propargyloxy)methyl]-6-mercaptopurine (15), 9-[(proparglyoxy)methyl]azathioprine (17), and angustmycin A analogue 10 showed inhibition of cancer cell growth, but only at a minimal level, and 17 also showed 14% cancer cel death in vitro. Compound 10 provided approximately 50% protection against HIV at 10(-4) M concentrations. Biodistribution results of [I-125]-10 in mice indicate that compound 10 is readily metabolized via deiodination in vivo, possibly by serving as a substrate for the enzyme S-adenosyl-L-homocysteine hydrolase. C1 OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831. NR 34 TC 18 Z9 18 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-2623 J9 J MED CHEM JI J. Med. Chem. PD APR 17 PY 1992 VL 35 IS 8 BP 1435 EP 1439 DI 10.1021/jm00086a012 PG 5 WC Chemistry, Medicinal SC Pharmacology & Pharmacy GA HQ011 UT WOS:A1992HQ01100012 PM 1573637 ER PT J AU LYKKE, KR WURZ, P AF LYKKE, KR WURZ, P TI DIRECT DETECTION OF NEUTRAL PRODUCTS FROM PHOTODISSOCIATED-C60 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Letter ID SINGLE-PHOTON IONIZATION; CARBON CLUSTER IONS; MULTIPHOTON IONIZATION; BUCKMINSTERFULLERENE; PARTICLES; UV AB Neutral products from photodissociated C60 detected with one-photon ionization are reported for the first time. The distribution of neutral fragments is very similar to the distribution of ion fragments. This suggests that multiphoton ionization/fragmentation of C60 does not require a ladder-switching mechanism. RP LYKKE, KR (reprint author), ARGONNE NATL LAB,DIV MAT SCI CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 23 TC 48 Z9 49 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 16 PY 1992 VL 96 IS 8 BP 3191 EP 3193 DI 10.1021/j100187a004 PG 3 WC Chemistry, Physical SC Chemistry GA HQ013 UT WOS:A1992HQ01300004 ER PT J AU BROECKER, WS PENG, TH AF BROECKER, WS PENG, TH TI INTERHEMISPHERIC TRANSPORT OF CARBON-DIOXIDE BY OCEAN CIRCULATION SO NATURE LA English DT Article ID EDDY DIFFUSION-MODEL; 25-DEGREES-N LATITUDE; ATLANTIC-OCEAN; CURRENTS; CYCLE AB ALTHOUGH anthropogenic emissions of carbon dioxide have today created a greater atmospheric CO2 concentration in the Northern than in the Southern Hemisphere, a comparison of interhemispheric CO2 profiles from 1980 and 1962 led Keeling and Heimann 1,2 to conclude that, before the Industrial Revolution, natural CO2 sources and sinks acted to set up a reverse (south to north) gradient which drove about one gigatonne of carbon each year through the atmosphere from the Southern to the Northern Hemisphere. At steady state, this flux must have been balanced by a counter flow of carbon from north to south through the ocean. Here we present a means to estimate this natural flux by a separation of oceanic carbon anomalies into those created by biogenic processes and those created by CO2 exchange between the ocean and atmosphere. We find that before the Industrial Revolution, deep water formed in the northern Atlantic Ocean carried about 0.6 gigatonnes of carbon annually to the Southern Hemisphere, providing support for Keeling and Heimann's proposal. The existence of this oceanic carbon pump also raises questions about the need for a large terrestrial carbon sink in the Northern Hemisphere, as postulated by Tans et al. 3, to balance the present global carbon budget. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37830. RP BROECKER, WS (reprint author), COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964, USA. NR 18 TC 88 Z9 89 U1 1 U2 14 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 16 PY 1992 VL 356 IS 6370 BP 587 EP 589 DI 10.1038/356587a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP031 UT WOS:A1992HP03100043 ER PT J AU RITSON, DM AF RITSON, DM TI TELLERS WAR - THE TOP-SECRET STORY BEHIND THE STAR-WARS DECEPTION - BROAD,WL SO NATURE LA English DT Book Review RP RITSON, DM (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 16 PY 1992 VL 356 IS 6370 BP 627 EP 627 DI 10.1038/356627a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP031 UT WOS:A1992HP03100060 ER PT J AU LAURITSEN, T JANSSENS, RVF CARPENTER, MP MOORE, EF AHMAD, I FERNANDEZ, PB KHOO, TL KUEHNER, JA PREVOST, D WADDINGTON, JC GARG, U REVIOL, W YE, D DRIGERT, MW AF LAURITSEN, T JANSSENS, RVF CARPENTER, MP MOORE, EF AHMAD, I FERNANDEZ, PB KHOO, TL KUEHNER, JA PREVOST, D WADDINGTON, JC GARG, U REVIOL, W YE, D DRIGERT, MW TI DYNAMIC MOMENT OF INERTIA OF THE HG-192 SUPERDEFORMED BAND AT HIGH ROTATIONAL FREQUENCIES SO PHYSICS LETTERS B LA English DT Article ID NUCLEI; A=190 AB The superdeformed band in Hg-192 has been extended to higher transition energies from a new analysis of a large set of double and triple coincidence data. Contrary to the results of cranked shell model calculations including monopole pairing, the dynamic moment of inertia J(2) is found to continue to increase with rotational frequency. C1 MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4L8,ONTARIO,CANADA. UNIV NOTRE DAME,NOTRE DAME,IN 46556. EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. RP LAURITSEN, T (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 22 TC 30 Z9 30 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 16 PY 1992 VL 279 IS 3-4 BP 239 EP 243 DI 10.1016/0370-2693(92)90386-I PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HQ370 UT WOS:A1992HQ37000008 ER PT J AU KALASHNIKOV, OK AF KALASHNIKOV, OK TI QCD INFRARED POLE AT FINITE TEMPERATURE SO PHYSICS LETTERS B LA English DT Article AB It is shown that the well-known infrared singularity (which is an attribute of any perturbative Green functions within statistical QCD) is still not ruled out although (when the axial gauge being fixed) the nonzero gluon magnetic mass seems to solve this problem. C1 PN LEBEDEV PHYS INST,DEPT THEORET PHYS,MOSCOW 117924,USSR. RP KALASHNIKOV, OK (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 22 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 16 PY 1992 VL 279 IS 3-4 BP 367 EP 372 DI 10.1016/0370-2693(92)90406-T PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HQ370 UT WOS:A1992HQ37000028 ER PT J AU DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R ARIZTIZABAL, F CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A PASCUAL, A CREANZA, D DEPALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BAUERDICK, LAT BLUCHER, E BONVICINI, G BOSSI, F BOUDREAU, J BURNETT, TH DREVERMANN, H FORTY, RW HAGELBERG, R HAYWOOD, S HILGART, J JACOBSEN, R JOST, B KASEMANN, M KNOBLOCH, J LANCON, E LEHRAUS, I LOHSE, T LUSIANI, A MARTINEZ, M MATO, P MATTISON, T MEINHARD, H MENARY, S MEYER, T MINTEN, A MIOTTO, A MIQUEL, R MOSER, HG NASH, J PALAZZI, P PERLAS, JA RANJARD, F REDLINGER, G ROLANDI, L ROTH, A ROTHBERG, J RUAN, T SAICH, M SCHLATTER, D SCHMELLING, M TEJESSY, W WACHSMUTH, H WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BADAUD, F BARDADINOTWINOWSKA, M BENCHEIKH, AM ELFELLOUS, R FALVARD, A GAY, P GUICHENEY, C HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PIETRZYK, B PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BRIENT, JC FOUQUE, G GAMESS, A HARVEY, J ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ PARSONS, MI VEITCH, E MONETA, L PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L WASSERBAECH, S ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CERUTTI, F CHIARELLA, V DETTORREPIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP PASSALACQUA, L PEPEALTARELLI, M PICCHI, P ALTOON, B BOYLE, O COLRAIN, P HALLEY, AW TENHAVE, I LYNCH, JG MAITLAND, W MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M COLLING, DJ DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G JACKSON, D KEEMER, NR NUTTALL, M PATEL, A SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T KLEINKNECHT, K RAAB, J RENK, B ROEHN, S SANDER, HG SCHMIDT, H STEEG, F WALTHER, SM WOLF, B AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A CARR, J COYLE, P DRINKARD, J ETIENNE, F PAPALEXIOU, S PAYRE, P QIAN, Z ROUSSEAU, D SCHWEMLING, P TALBY, M ADLUNG, S BECKER, H BLUM, W BROWN, D CATTANEO, P COWAN, G DEHNING, B DIETL, H DYDAK, F FERNANDEZBOSMAN, M FRANK, M HANSLKOZANECKA, T LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R ROTSCHEIDT, H SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U STIEGLER, U STDENIS, R TAKASHIMA, M THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GRIVAZ, JF HEUSSE, P JANOT, P KIM, DW LEDIBERDER, F LEFRANCOIS, J LUTZ, AM SCHUNE, MH VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F ABBANEO, D AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELLORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GATTO, C GIASSI, A GIORGI, MA LIGABUE, F MANNELLI, EB MARROCCHESI, PS MESSINEO, A PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T QUAZI, IS STRONG, JA WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCHDEVAUX, B COLAS, P KOZANECKI, W LEMAIRE, MC LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J MOHAND, DS VALLAGE, B JOHNSON, RP LITKE, AM WEAR, J ASHMAN, JG BABBAGE, W BOOTH, CN BUTTAR, C CARNEY, RE CARTWRIGHT, S COMBLEY, F HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BARBERIO, E BRANDT, S GRUPEN, C MIRABITO, L SCHAFER, U SEYWERD, H GANIS, G GIANNINI, G GOBBO, B RAGUSA, F BELLANTONI, L CINABRO, D CONWAY, JS COWEN, DF FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JARED, RC LECLAIRE, BW LISHKA, C PAN, YB PATER, JR SAADI, Y SHARMA, V SCHMITT, M SHI, ZH TANG, YH WALSH, AM WEBER, FV WHITNEY, MH WU, SL WU, X ZOBERNIG, G AF DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R ARIZTIZABAL, F CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A PASCUAL, A CREANZA, D DEPALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BAUERDICK, LAT BLUCHER, E BONVICINI, G BOSSI, F BOUDREAU, J BURNETT, TH DREVERMANN, H FORTY, RW HAGELBERG, R HAYWOOD, S HILGART, J JACOBSEN, R JOST, B KASEMANN, M KNOBLOCH, J LANCON, E LEHRAUS, I LOHSE, T LUSIANI, A MARTINEZ, M MATO, P MATTISON, T MEINHARD, H MENARY, S MEYER, T MINTEN, A MIOTTO, A MIQUEL, R MOSER, HG NASH, J PALAZZI, P PERLAS, JA RANJARD, F REDLINGER, G ROLANDI, L ROTH, A ROTHBERG, J RUAN, T SAICH, M SCHLATTER, D SCHMELLING, M TEJESSY, W WACHSMUTH, H WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BADAUD, F BARDADINOTWINOWSKA, M BENCHEIKH, AM ELFELLOUS, R FALVARD, A GAY, P GUICHENEY, C HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PIETRZYK, B PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BRIENT, JC FOUQUE, G GAMESS, A HARVEY, J ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ PARSONS, MI VEITCH, E MONETA, L PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L WASSERBAECH, S ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CERUTTI, F CHIARELLA, V DETTORREPIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP PASSALACQUA, L PEPEALTARELLI, M PICCHI, P ALTOON, B BOYLE, O COLRAIN, P HALLEY, AW TENHAVE, I LYNCH, JG MAITLAND, W MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M COLLING, DJ DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G JACKSON, D KEEMER, NR NUTTALL, M PATEL, A SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T KLEINKNECHT, K RAAB, J RENK, B ROEHN, S SANDER, HG SCHMIDT, H STEEG, F WALTHER, SM WOLF, B AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A CARR, J COYLE, P DRINKARD, J ETIENNE, F PAPALEXIOU, S PAYRE, P QIAN, Z ROUSSEAU, D SCHWEMLING, P TALBY, M ADLUNG, S BECKER, H BLUM, W BROWN, D CATTANEO, P COWAN, G DEHNING, B DIETL, H DYDAK, F FERNANDEZBOSMAN, M FRANK, M HANSLKOZANECKA, T LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R ROTSCHEIDT, H SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U STIEGLER, U STDENIS, R TAKASHIMA, M THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GRIVAZ, JF HEUSSE, P JANOT, P KIM, DW LEDIBERDER, F LEFRANCOIS, J LUTZ, AM SCHUNE, MH VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F ABBANEO, D AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELLORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GATTO, C GIASSI, A GIORGI, MA LIGABUE, F MANNELLI, EB MARROCCHESI, PS MESSINEO, A PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T QUAZI, IS STRONG, JA WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCHDEVAUX, B COLAS, P KOZANECKI, W LEMAIRE, MC LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J MOHAND, DS VALLAGE, B JOHNSON, RP LITKE, AM WEAR, J ASHMAN, JG BABBAGE, W BOOTH, CN BUTTAR, C CARNEY, RE CARTWRIGHT, S COMBLEY, F HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BARBERIO, E BRANDT, S GRUPEN, C MIRABITO, L SCHAFER, U SEYWERD, H GANIS, G GIANNINI, G GOBBO, B RAGUSA, F BELLANTONI, L CINABRO, D CONWAY, JS COWEN, DF FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JARED, RC LECLAIRE, BW LISHKA, C PAN, YB PATER, JR SAADI, Y SHARMA, V SCHMITT, M SHI, ZH TANG, YH WALSH, AM WEBER, FV WHITNEY, MH WU, SL WU, X ZOBERNIG, G TI MEASUREMENT OF THE TAU-LEPTON LIFETIME SO PHYSICS LETTERS B LA English DT Article AB The mean lifetime of the tau-lepton is measured from a sample of Z --> tau+-tau- decays observed with the ALEPH detector at LEP in 1989 and 1990. A new technique is applied to the events containing two one-prong decays: the lifetime is measured from the observed correlation between the impact parameters and azimuthal angles of the two charged tracks. The lifetime is also determined from measured vertex displacements for three-prong decays and track impact parameters for one-prong decays, The combined result is tau(tau) = 291 +/- 13 (stat.) +/- 6 (syst.) fs. C1 UNIV AUTONOMA BARCELONA,INST FIS ALTES ENERGIES,E-08193 BARCELONA,SPAIN. IST NAZL FIS NUCL,SEZ BARI,BARI,ITALY. UNIV BARI,DIPARTIMENTO FIS,I-70126 BARI,ITALY. CHINESE ACAD SCI,INST HIGH ENERGY PHYS,BEIJING,PEOPLES R CHINA. CERN,EUROPEAN LAB PARTICLE PHYS,CH-1211 GENEVA 23,SWITZERLAND. UNIV CLERMONT FERRAND,INST NATL PHYS NUCL & PHYS PARTICULES,CNRS,PHYS CORPUSULAIRE LAB,F-63177 CLERMONT FERRAND,FRANCE. NIELS BOHR INST,COPENHAGEN,DENMARK. DEMOCRITOS NUCL RES CTR,ATHENS,GREECE. ECOLE POLYTECH,INST NATL PHYS NUCL & PHYS PARTICULES,CNRS,F-91128 PALAISEAU,FRANCE. UNIV EDINBURGH,DEPT PHYS,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. UNIV FLORENCE,DIPARTIMENTO FIS,I-50125 FLORENCE,ITALY. IST NAZL FIS NUCL,SEZ FIRENZE,I-50125 FLORENCE,ITALY. FLORIDA STATE UNIV,SUPERCOMP COMPUTAT RES INST,TALLAHASSEE,FL 32306. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. INST NAZL FIS NUCL,LAB NAZL,I-00044 FRASCATI,ITALY. UNIV GLASGOW,DEPT PHYS & ASTRON,GLASGOW G12 8QQ,SCOTLAND. UNIV HEIDELBERG,INST HOCHENERGIEPHYS,W-6900 HEIDELBERG,GERMANY. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,DEPT PHYS,LONDON SW7 2BZ,ENGLAND. UNIV INNSBRUCK,INST EXPTL PHYS,A-6020 INNSBRUCK,AUSTRIA. UNIV LANCASTER,DEPT PHYS,LANCASTER LA1 4YB,ENGLAND. UNIV MAINZ,INST PHYS,W-6500 MAINZ,GERMANY. FAC SCI LUMINY,INST NATL PHYS NUCL & PHYS PARTICULES,CNRS,CTR PHYS PARTICULES,F-13288 MARSEILLE,FRANCE. MAX PLANCK INST PHYS & ASTROPHYS,WERNER HEISENBERG INST PHYS,W-8000 MUNICH 40,GERMANY. UNIV PARIS 11,INST NATL PHYS NUCL & PHYS PARTICULES,CNRS,F-91405 ORSAY,FRANCE. UNIV PISA,DIPARTIMENTO FIS,INST NAZL FIS NUCL,SEZ PISA,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. UNIV LONDON,ROYAL HOLLOWAY & BEDFORD NEW COLL,DEPT PHYS,SURREY TW20 0EX,ENGLAND. RUTHERFORD APPLETON LAB,DEPT PARTICLE PHYS,DIDCOT OX11 0QX,OXON,ENGLAND. CENS,DEPT PHYS PARTICULES ELEMENTAIRES,F-91191 GIF SUR YVETTE,FRANCE. UNIV CALIF SANTA CRUZ,INST PARTICLE PHYS,SANTA CRUZ,CA 95064. UNIV SHEFFIELD,DEPT PHYS,SHEFFIELD S3 7RH,S YORKSHIRE,ENGLAND. UNIV SIEGEN,FACHBEREICH PHYS,W-5900 SIEGEN,GERMANY. UNIV TRIESTE,DIPARTIMENTO FIS,I-34127 TRIESTE,ITALY. IST NAZL FIS NUCL,SEZ TRIESTE,TRIESTE,ITALY. UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. UNIV TURIN,IST FIS GEN,I-10124 TURIN,ITALY. NAPLES UNIV,DIPARTIMENTO SCI FIS,I-80138 NAPLES,ITALY. CNR,IST COSMO GEOFIS,TURIN,ITALY. CERN,PPE DIV,CH-1211 GENEVA 23,SWITZERLAND. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP DECAMP, D (reprint author), CNRS,INST NATL PHYS NUCL & PHYS PARTICULES,PHYS PARTICULES LAB,F-74019 ANNECY LE VIEUX,FRANCE. RI Ligabue, Franco/F-3432-2014; Bosman, Martine/J-9917-2014; Fernandez, Enrique/L-5387-2014; Mir, Lluisa-Maria/G-7212-2015; ciocci, maria agnese /I-2153-2015; Hansen, John/B-9058-2015; Lusiani, Alberto/N-2976-2015; Marrocchesi, Pier Simone/N-9068-2015; Lusiani, Alberto/A-3329-2016; Murtas, Fabrizio/B-5729-2012; Booth, Christopher/B-5263-2016; Pacheco Pages, Andres/C-5353-2011; Ferrante, Isidoro/F-1017-2012; ANTONELLI, ANTONELLA/C-6238-2011; Colas, Paul/F-2876-2013; Delfino, Manuel/A-1545-2012; Buttar, Craig/D-3706-2011; Stahl, Achim/E-8846-2011; Passalacqua, Luca/F-5127-2011; St.Denis, Richard/C-8997-2012; Forti, Francesco/H-3035-2011; Focardi, Ettore/E-7376-2012; Venturi, Andrea/J-1877-2012; Perrier, Frederic/A-5953-2011; Rolandi, Luigi (Gigi)/E-8563-2013 OI Palazzi, Paolo/0000-0002-4861-391X; RASO, Giuseppe/0000-0002-5660-3711; Bottigli, Ubaldo/0000-0002-0666-3433; Ligabue, Franco/0000-0002-1549-7107; Bloch-Devaux, Brigitte/0000-0002-2463-1232; Murtas, Fabrizio/0000-0002-7041-6541; Garrido Beltran, Lluis/0000-0001-8883-6539; Edgecock, Rob/0000-0002-7896-3312; Miquel, Ramon/0000-0002-6610-4836; Bosman, Martine/0000-0002-7290-643X; Fernandez, Enrique/0000-0002-6405-9488; Mir, Lluisa-Maria/0000-0002-4276-715X; ciocci, maria agnese /0000-0003-0002-5462; Hansen, John/0000-0002-8422-5543; Lusiani, Alberto/0000-0002-6876-3288; Marrocchesi, Pier Simone/0000-0003-1966-140X; Lusiani, Alberto/0000-0002-6876-3288; Booth, Christopher/0000-0002-6051-2847; Pacheco Pages, Andres/0000-0001-8210-1734; Ferrante, Isidoro/0000-0002-0083-7228; Delfino, Manuel/0000-0002-9468-4751; Stahl, Achim/0000-0002-8369-7506; Forti, Francesco/0000-0001-6535-7965; Focardi, Ettore/0000-0002-3763-5267; Rolandi, Luigi (Gigi)/0000-0002-0635-274X NR 22 TC 21 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 16 PY 1992 VL 279 IS 3-4 BP 411 EP 421 DI 10.1016/0370-2693(92)90413-X PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HQ370 UT WOS:A1992HQ37000035 ER PT J AU JEFFREY, GA RUBLE, JR MATIAS, P MCMULLAN, RK LUGER, P BUSCHMANN, J AF JEFFREY, GA RUBLE, JR MATIAS, P MCMULLAN, RK LUGER, P BUSCHMANN, J TI NEUTRON-DIFFRACTION REFINEMENT OF TRANS-2,5-DICHLORO-1,4-DIOXANE AT 97 K SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article AB C4H6Cl2O2, M(r) = 157.00, triclinic, P1BAR, a = 4.504 (2), b = 5.423 (2), c = 6.592 (3) angstrom, alpha = 85.53 (2), beta = 103.75 (2), gamma = 106.51 (1)-degrees, V = 149.9 (2) angstrom 3, Z = 1, D(n) = 1.739 Mg m-3, lambda(n)(Be, 002) V 1.0504 angstrom, mu = 0.1924 mm-1, F(000) = 34.911 fm, T = 97 K, R(F2) = 0.021, wR(F2) = 0.036 for 1183 unique reflections. The bond lengths not involving H atoms are in agreement with an earlier X-ray anlaysis to within 0.004 angstrom. C-Cl bonds are axial and longer than normal; C-O bonds are shorter than normal. The equatorial C-H bond lengths are significantly longer than the axial C-H bonds. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. FREE UNIV BERLIN,INST KRISTALLOG,W-1000 BERLIN 33,GERMANY. RP JEFFREY, GA (reprint author), UNIV PITTSBURGH,DEPT CRYSTALLOG,PITTSBURGH,PA 15260, USA. RI Matias, Pedro/B-7180-2008 OI Matias, Pedro/0000-0001-6170-451X NR 15 TC 0 Z9 0 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD APR 15 PY 1992 VL 48 BP 707 EP 709 DI 10.1107/S0108270191011113 PN 4 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA HR804 UT WOS:A1992HR80400038 ER PT J AU ZELICOFF, AP AF ZELICOFF, AP TI MYOCARDIAL-INFARCTION PREDICTION BY ARTIFICIAL NEURAL NETWORKS SO ANNALS OF INTERNAL MEDICINE LA English DT Letter RP ZELICOFF, AP (reprint author), SANDIA NATL LABS,DIV 9241,ALBUQUERQUE,NM 87185, USA. NR 2 TC 2 Z9 2 U1 0 U2 0 PU AMER COLL PHYSICIANS PI PHILADELPHIA PA INDEPENDENCE MALL WEST 6TH AND RACE ST, PHILADELPHIA, PA 19106-1572 SN 0003-4819 J9 ANN INTERN MED JI Ann. Intern. Med. PD APR 15 PY 1992 VL 116 IS 8 BP 701 EP 701 PG 1 WC Medicine, General & Internal SC General & Internal Medicine GA HN844 UT WOS:A1992HN84400029 PM 1546880 ER PT J AU GADBOIS, DM HAMAGUCHI, JR SWANK, RA BRADBURY, EM AF GADBOIS, DM HAMAGUCHI, JR SWANK, RA BRADBURY, EM TI STAUROSPORINE IS A POTENT INHIBITOR OF P34CDC2 AND P34CDC2-LIKE KINASES SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article ID ORNITHINE DECARBOXYLASE INDUCTION; MOUSE EPIDERMAL-CELLS; PROTEIN-KINASE; C INHIBITOR; PHASE; GENE C1 UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616. RP GADBOIS, DM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,MAIL STOP M880,LOS ALAMOS,NM 87545, USA. NR 20 TC 133 Z9 133 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD APR 15 PY 1992 VL 184 IS 1 BP 80 EP 85 DI 10.1016/0006-291X(92)91160-R PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA HP168 UT WOS:A1992HP16800012 PM 1567459 ER PT J AU CLAUSING, RE HEATHERLY, L HORTON, LL SPECHT, ED BEGUN, GM WANG, ZL AF CLAUSING, RE HEATHERLY, L HORTON, LL SPECHT, ED BEGUN, GM WANG, ZL TI TEXTURES AND MORPHOLOGIES OF CHEMICAL VAPOR-DEPOSITED (CVD) DIAMOND SO DIAMOND AND RELATED MATERIALS LA English DT Article ID FILMS C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RI Specht, Eliot/A-5654-2009 OI Specht, Eliot/0000-0002-3191-2163 NR 13 TC 72 Z9 74 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD APR 15 PY 1992 VL 1 IS 5-6 BP 411 EP 415 DI 10.1016/0925-9635(92)90139-F PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA JE678 UT WOS:A1992JE67800003 ER PT J AU VANDERSLUYS, WG HUFFMAN, JC EHLER, DS SAUER, NN AF VANDERSLUYS, WG HUFFMAN, JC EHLER, DS SAUER, NN TI DISSOLUTION OF URANIUM METAL USING IODINE AND 2-PROPANOL - SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF TETRAIODOTETRAISOPROPOXYBIS(2-PROPANOL)DIURANIUM SO INORGANIC CHEMISTRY LA English DT Note ID ALKOXIDES; PRECURSORS; CHEMISTRY; ADDUCTS AB Clean uranium metal turnings react with iodine in 2-propanol at room temperature to give solutions of the monomer, UI2(O-i-Pr)2(HO-i-Pr)2. Concentration of the solution gives purple crystals which readily lose solvent. Recrystallization of the monomer from toluene gives green crystals of the dimer U2I4(O-i-Pr)4(HO-i-Pr)2, which has been structurally characterized. U + I2 + 2HO-i-Pr --> HO-i-Pr H-2 + UI2(O-i-Pr)2(HO-i-Pr)2 UI2(O-i-Pr)2(HO-i-Pr)2 --> -2HO-i-Pr U2I4(O-i-Pr)4(Ho-i-Pr)2 C1 INDIANA UNIV,CTR MOLEC STRUCT,DEPT CHEM,BLOOMINGTON,IN 47401. UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPE & NUCL CHEM,INORGAN & STRUCT CHEM GRP,LOS ALAMOS,NM 87545. RP VANDERSLUYS, WG (reprint author), UNIV MONTANA,DEPT CHEM,MISSOULA,MT 59812, USA. NR 15 TC 12 Z9 12 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 15 PY 1992 VL 31 IS 8 BP 1316 EP 1318 DI 10.1021/ic00034a004 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA HP288 UT WOS:A1992HP28800004 ER PT J AU BELYTSCHKO, T PLASKACZ, EJ AF BELYTSCHKO, T PLASKACZ, EJ TI SIMD IMPLEMENTATION OF A NONLINEAR TRANSIENT SHELL PROGRAM WITH PARTIALLY STRUCTURED MESHES SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article ID STABLE TIME STEPS; NONLINEAR DYNAMICS; CONNECTION MACHINE; FINITE-ELEMENTS; EIGENVALUES; ALGORITHMS AB The implementation of an explicit transient program for the three-dimensional non-linear finite element analysis of shells on a massively parallel SIMD computer, the CONNECTION Machine, is described. Particular emphasis is placed on interprocessor communication using router and NEWS schemes. A hybrid communication scheme, where NEWS is used within structured subdomains and the router is used to exchange nodal forces between subdomains, is examined. It is shown that the 'mesh-structure index' of most large meshes is sufficient to make hybrid schemes effective and this is verified by computer runs. Some benchmark non-linear calculations with 8K to 32K elements are also presented. C1 ARGONNE NATL LAB, DIV COMP & TELECOMMUN, ARGONNE, IL 60439 USA. RP NORTHWESTERN UNIV, INST TECHNOL, ROBERT R MCCORMICK SCH ENGN & APPL SCI, DEPT CIVIL ENGN, EVANSTON, IL 60208 USA. RI Belytschko, Ted/B-6710-2009 NR 33 TC 11 Z9 11 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0029-5981 EI 1097-0207 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD APR 15 PY 1992 VL 33 IS 5 BP 997 EP 1026 DI 10.1002/nme.1620330508 PG 30 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA HJ796 UT WOS:A1992HJ79600007 ER PT J AU STOFFELS, JJ LAUE, HJ AF STOFFELS, JJ LAUE, HJ TI ION TRANSMISSION STUDIES OF MULTIPLE-SECTOR ISOTOPE-RATIO MASS SPECTROMETERS SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article DE ION TRANSMISSION EFFICIENCY; ANALYZER FOCUSING; V-FILAMENT ION SOURCE; ISOTOPE-RATIO MASS SPECTROMETERS AB Theoretical and experimental studies were conducted to determine the ion transmission efficiency of multiple-sector isotope-ratio mass spectrometers with tandem magnets of normal geometry. The computer program GIOS (general ion optical systems) was used to perform theoretical calculations of focusing properties and ion transmission efficiency. Actual transmission through multiple-sector instruments was determined from measurements of the ion beam vertical profile at the focus of each sector. Transmission was found to be strongly dependent on source filament geometry. The studies also determined a way to significantly increase ion transmission without changing the basic geometry of existing instruments. A cylindrical einzel lens located near the focus between the magnets provides vertical focusing of the ion beam without perturbing focal properties in the plane of mass dispersion. With a single V-filament ion source, a transmission increase from almost-equal-to 75% to almost-equal-to 100% was achieved. C1 PURDUE UNIV, W LAFAYETTE, IN 47907 USA. RP STOFFELS, JJ (reprint author), PACIFIC NW LAB, POB 999,BATTELLE BLVD, RICHLAND, WA 99352 USA. NR 14 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD APR 15 PY 1992 VL 114 IS 1-2 BP 47 EP 60 DI 10.1016/0168-1176(92)85021-Q PG 14 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA HP438 UT WOS:A1992HP43800004 ER PT J AU MENDEL, CW SAVAGE, ME ZAGAR, DM SIMPSON, WW GRASSER, TW QUINTENZ, JP AF MENDEL, CW SAVAGE, ME ZAGAR, DM SIMPSON, WW GRASSER, TW QUINTENZ, JP TI EXPERIMENTS ON A CURRENT-TOGGLED PLASMA-OPENING SWITCH SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Plasma-opening switches have been used to improve pulsed-power wave shapes for over a decade. These switches have used the inertia of the plasma to hold the switch closed. This results in conflicting requirements when long hold-off time and fast opening are required, and also results in variation in opening current due to variation in initial plasma fill. The current-toggled plasma-opening switch attempts to overcome these problems by using external magnetic fields rather than inertia to control the plasma conductor. Data will be presented showing several features of the operation of this switch. These data will be compared to models used to design the switch. The comparisons indicate that the mass can be measured approximately from fast coil data and that the slow coil flux does set the opening level of the current. They also indicate that the opening current is somewhat dependent upon plasma mass, and that the design of the field coils that provide the control fields must be done more carefully to provide a switch that opens satisfactorily. RP MENDEL, CW (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 17 TC 47 Z9 51 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1992 VL 71 IS 8 BP 3731 EP 3746 DI 10.1063/1.350883 PG 16 WC Physics, Applied SC Physics GA HP366 UT WOS:A1992HP36600010 ER PT J AU TAN, ZQ HEALD, SM AF TAN, ZQ HEALD, SM TI INTERFACIAL REACTIONS BETWEEN NICKEL CHROMIUM-ALLOYS AND ALUMINUM SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ABSORPTION FINE-STRUCTURE; REFLECTIVITY; AL AB We have studied the interface structure and reactions of Ni-Cr alloy and Al thin film bilayers using glancing-angle x-ray reflectivity and extended x-ray-absorption fine structure techniques. The Al/Ni-Cr bilayers were prepared by evaporation in ultrahigh vacuum with a clean interface (Clean) or an interface exposed to 600 Langmuir oxygen (O-exposed). No interfacial reaction is observed at room temperature in either the Clean or the O-exposed samples. Upon annealing for 10 minutes, initial reaction occurs at about 250-degrees-C in the Clean sample and 310-degrees-C in the O-exposed sample. The oxygen impurity at the interface retards the initial reaction and also modifies the diffusion behavior. In both Clean and O-exposed systems, the reaction starts between Ni and Al forming NiAl3. The reaction results in a Cr-rich region near the interface which transforms to the bcc structure. Only at higher temperatures do Cr and Al react to form CrAl7. The role of various diffusion channels and oxygen impurity at the interface in relationship to the reaction pattern will be discussed. RP TAN, ZQ (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 12 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1992 VL 71 IS 8 BP 3766 EP 3772 DI 10.1063/1.350887 PG 7 WC Physics, Applied SC Physics GA HP366 UT WOS:A1992HP36600014 ER PT J AU CHAUDHURI, J GONDHALEKAR, V JANKOWSKI, AF AF CHAUDHURI, J GONDHALEKAR, V JANKOWSKI, AF TI ANALYSIS OF THE STRAIN PROFILE IN THIN AU/NI MULTILAYERS BY X-RAY-DIFFRACTION SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID METALLIC MULTILAYERS; GOLD-NICKEL; MODULUS; FILMS; NI AB The strain relaxation in Au/Ni multilayers was analyzed in detail using a dynamical theory of x-ray diffraction. The depth profile of strain in the modulation direction was determined by an iterative fitting of the calculated rocking curve with the experimental one. The repeat periods of Au/Ni multilayers used in this study range from 0.82 to 9.0 nm. The analysis indicates that the theoretical x-ray patterns are extremely sensitive to the amount of strain at the interface. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP CHAUDHURI, J (reprint author), WICHITA STATE UNIV,NATL INST AVIAT RES,DEPT MECH ENGN,WICHITA,KS 67208, USA. RI Chaudhuri, Jharna/E-8863-2013 NR 24 TC 18 Z9 18 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1992 VL 71 IS 8 BP 3816 EP 3820 DI 10.1063/1.350896 PG 5 WC Physics, Applied SC Physics GA HP366 UT WOS:A1992HP36600023 ER PT J AU WAHLSTRAND, KJ YEE, JH AF WAHLSTRAND, KJ YEE, JH TI FOURIER-SERIES METHOD APPLIED TO DIFFERENT SHAPED QUANTUM-WELL LASER POTENTIALS SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Here we present a method using Fourier series representation of the potential to obtain the eigenvalues and eigenfunctions for a general isolated quantum well potential. We compare the method with analytical results in the case of a square well and get excellent agreement. Finally, we apply the method to two different graded-index, separate confinement heterostructure potentials of interest and compute the corresponding gain with k selection. We find the gain to be much narrower in energy range for multiple quantum wells as compared with a single quantum well. RP WAHLSTRAND, KJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,MAIL CODE L-156,LIVERMORE,CA 94550, USA. NR 5 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1992 VL 71 IS 8 BP 3894 EP 3897 DI 10.1063/1.350856 PG 4 WC Physics, Applied SC Physics GA HP366 UT WOS:A1992HP36600035 ER PT J AU JOHNSON, WA MENDEL, CW SEIDEL, DB AF JOHNSON, WA MENDEL, CW SEIDEL, DB TI TER AZIMUTHAL MODES FOR A BICONIC TRANSMISSION-LINE IN THE SMALL-GAP LIMIT SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Azimuthally asymmetric modes in a biconic transmission line with a small-gap angle may be approximated by "transmission-line-like" modes. It is shown that the errors in these approximations are second order in the gap angle and approximate error bounds are provided. As an example demonstrating the application of this analysis in biconic structures, an analysis to characterize of the electromagnetic waves in the vacuum feed of the Particle Beam Fusion Accelerator II is provided. RP JOHNSON, WA (reprint author), SANDIA NATL LABS,FUS RES DEPT,ALBUQUERQUE,NM 87185, USA. NR 5 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1992 VL 71 IS 8 BP 4034 EP 4039 DI 10.1063/1.350827 PG 6 WC Physics, Applied SC Physics GA HP366 UT WOS:A1992HP36600058 ER PT J AU WEDEMAYER, GJ KIDD, DG WEMMER, DE GLAZER, AN AF WEDEMAYER, GJ KIDD, DG WEMMER, DE GLAZER, AN TI PHYCOBILINS OF CRYPTOPHYCEAN ALGAE - OCCURRENCE OF DIHYDROBILIVERDIN AND MESOBILIVERDIN IN CRYPTOMONAD BILIPROTEINS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID BILIN ATTACHMENT SITES; CHROOMONAS SP CRYPTOPHYCEAE; SP-NOV CRYPTOPHYCEAE; AMINO-ACID-SEQUENCE; ALPHA-SUBUNIT; PICOSECOND FLUORESCENCE; INVITRO ATTACHMENT; B-PHYCOERYTHRIN; ENERGY-TRANSFER; BETA-SUBUNIT AB Structures of the open-chain tetrapyrrole (bilin) prosthetic groups of the cryptophycean biliproteins phycocyanin 645 (Cr-PC 645; from strain UW374), phycoerythrin 566 (Cr-PE 566; from strain Bermani) and phycoerythrin 545 (Cr-PE 545; from Proteomonas sulcata Hill & Wetherbee) were examined by absorption, H-1 NMR spectroscopy, and mass spectrometry. These biliproteins carry the following covalently attached bilins: Cr-PC 645 (alpha-subunit) has one mesobiliverdin, (beta-subunit), two phycocyanobilins and a doubly linked 15,16-dihydrobiliverdin; Cr-PC 566 (alpha), bilin 584, (beta), phycoerythrobilin and two bilin 584 chromophores (Wedemayer, G. J., Wemmer, D. E., and Glazer, A. N. (1991) J. Biol. Chem. 266, 4731-4741); Cr-PE 545 (alpha) has one 15,16-dihydrobiliverdin and (beta), only phycoerythrobilins. This is the first report of naturally occurring biliproteins carrying either 15,16-dihydrobiliverdin or mesobiliverdin chromophores. Native cryptomonad phycobiliproteins have been classified on the basis of the position of their long wavelength absorption maxima. However, comparison of the bilins of Cr-PE 566 from strain Bermani with those of Cr-PE 566 of strain CBD shows that the two proteins carry different bilins on the alpha-subunit. Consequently, the identity of the bilin prosthetic groups on cryptophycean phycobiliproteins cannot be unambiguously inferred from simple inspection of the visible absorption spectra. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV BIOCHEM & MOLEC BIOL,STANLEY DONNER ASU,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT PLANT BIOL,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720. FU NIGMS NIH HHS [GM28994] NR 66 TC 42 Z9 45 U1 0 U2 2 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 15 PY 1992 VL 267 IS 11 BP 7315 EP 7331 PG 17 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA HN485 UT WOS:A1992HN48500021 PM 1559975 ER PT J AU BRAUNSTEIN, M MCKOY, V DIXIT, SN AF BRAUNSTEIN, M MCKOY, V DIXIT, SN TI ROTATIONALLY RESOLVED PHOTOIONIZATION OF MOLECULAR-OXYGEN SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENHANCED MULTIPHOTON IONIZATION; SHAPE-RESONANCE; BRANCHING RATIOS; PHOTO-IONIZATION; PHOTOELECTRON-SPECTRA; CROSS-SECTIONS; ANGULAR-DISTRIBUTIONS; PROPENSITY RULES; KINETIC-ENERGY; C3-PI-G STATE AB We report the results of theoretical studies of the rotationally resolved photoelectron spectra of ground state O2 leading to the X (2)PI(g) state of O2+ via the absorption of a single vacuum ultraviolet photon. These studies elaborate on a recent report [M. Braunstein et al., J. Chem. Phys. 93, 5345 (1990)] where we showed that a shape resonance near threshold creates a significant dependence of the rotational branching ratios on the ion vibrational level. We also showed that analysis of the rotational branches yields detailed information on the angular momentum composition of the shape resonance. We continue this analysis giving a comprehensive derivation of the rotationally resolved cross sections and photoelectron angular distributions. We discuss the selection rules implied by these expressions and present very high resolution cross sections (J --> J+) obtained using static-exchange photoelectron orbitals and explicitly taking into account the internuclear distance dependence of the electronic transition moment. These cross sections illustrate the selection rules and show more explicitly the angular momentum composition of the shape resonance. We also present rotationally resolved photoelectron angular distributions which would be expected at low energy. C1 CALTECH,ARTHUR AMOS NOYES LAB CHEM PHYS,PASADENA,CA 91125. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,THEORET ATOM & MOLEC PHYS GRP,LIVERMORE,CA 94550. NR 41 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 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 5726 EP 5733 DI 10.1063/1.462671 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800019 ER PT J AU MELISSAS, VS TRUHLAR, DG GARRETT, BC AF MELISSAS, VS TRUHLAR, DG GARRETT, BC TI OPTIMIZED CALCULATIONS OF REACTION PATHS AND REACTION-PATH FUNCTIONS FOR CHEMICAL-REACTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-STATE-THEORY; INTRINSIC REACTION COORDINATE; SEMICLASSICAL TUNNELING CALCULATIONS; ORDINARY DIFFERENTIAL EQUATIONS; POTENTIAL-ENERGY SURFACE; COLLINEAR REACTIONS; HYDROGEN MOLECULES; STEEPEST DESCENT; REACTION RATES; APPROXIMATION AB In this paper we optimize several algorithms for the computation of reaction rates based on information calculated along minimum energy reaction paths and we evaluate the efficiencies of the optimized algorithms. The investigations are based on the calculation of chemical reaction rate constants using variational transition state theory and multidimensional semiclassical transmission coefficients including reaction path curvature. Several methods are evaluated and compared by a systematic set of applications to test cases involving the hydrogen-atom transfer reactions CH3 + H-2 --> CH4 + H and OH + H-2 --> H2O + H. For each method we present general recommendations for all algorithmic choices other than gradient step size so that future calculations may be carried out reasonably efficiently by varying only one parameter. In the process of these optimizations we have found that the accuracy of the Euler stabilization method can be significantly increased by choosing the auxiliary parameters differently than in previous work; the optimized algorithm is called ES1*. Our final recommendations for future work are (i) when the Hessian/gradient computational cost ratio is low (less-than-or-similar-to 3): The Page-McIver algorithm with the Hessian recalculated at every step, with a cubic starting step, and with curvature calculated from the derivative of the gradient, and (ii) when the Hessian/gradient computational cost ratio is moderate or large: the ES1* algorithm with a Hessian step size three times larger than the gradient step size, with a quadratic starting step, and with curvature calculated from the derivative of the gradient. C1 UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. RP MELISSAS, VS (reprint author), UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. RI Garrett, Bruce/F-8516-2011; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 86 TC 88 Z9 88 U1 2 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 5758 EP 5772 DI 10.1063/1.462674 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800022 ER PT J AU BUNTINE, MA BALDWIN, DP CHANDLER, DW AF BUNTINE, MA BALDWIN, DP CHANDLER, DW TI PHOTODISSOCIATION DYNAMICS OF DOUBLY EXCITED RYDBERG STATES OF MOLECULAR-HYDROGEN SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RESONANT MULTIPHOTON IONIZATION; VIBRATIONAL BRANCHING RATIOS; PHOTOIONIZATION DYNAMICS; PHOTOELECTRON-SPECTROSCOPY; DISSOCIATIVE IONIZATION; LINEAR-MOLECULES; CROSS-SECTIONS; LYMAN-ALPHA; H-2; AUTOIONIZATION AB We have applied photofragment ion imaging to investigate the dissociation dynamics of low-lying, doubly excited states of molecular hydrogen. A doubly excited electronic state is one in which both of the hydrogen electrons reside in excited molecular orbitals. Two-step, two-color multiphoton excitation of H-2, first via 201.8 nm, two-photon excitation into the E, F (1)SIGMA(g)+ (upsilon(E) = 0, J = 1) state, followed by approximately 563 nm, 1 + m (m = 1, 2) excitation through the B" (1)SIGMA(u)+ (upsilon = 0, J = 0, 2), D (1)PI(u) (upsilon = 2, J = 1, 2), and B' (1)SIGMA(u)+ (upsilon = 4, J = 0, 2) states provides a ready means of populating several low-lying doubly excited states of H-2 at increasing internuclear separations. From these doubly excited repulsive states, both dissociation and autoionization processes are possible. Because the excitation energy remains relatively constant as each intermediate state is accessed, differences in the photodissociation dynamics via each state can be ascribed directly to the effects of changing internuclear separation and electronic symmetry of the intermediate and dissociative states. H+ fragments detected from each photodissociation pathway are distinguished by their differing velocities, determined from an ion image. C1 SANDIA NATL LABS,LIVERMORE,CA 94550. RP BUNTINE, MA (reprint author), STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305, USA. RI Buntine, Mark/B-6878-2009 OI Buntine, Mark/0000-0003-0525-2795 NR 53 TC 33 Z9 33 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 5843 EP 5856 DI 10.1063/1.462682 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800031 ER PT J AU MCCARTHY, MI HESS, AC AF MCCARTHY, MI HESS, AC TI PERIODIC HARTREE-FOCK STUDIES OF THE PROPERTIES OF THE CL2/MGO (001) INTERFACE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CO ADSORPTION THEOREON; MGO(110) SURFACE; CARBON-MONOXIDE; MGO SURFACES; CHEMISORPTION; ABINITIO AB The properties of the Cl2/MgO (001) interface were investigated using the ab initio periodic Hartree-Fock LCAO method. The calculations treated a system that was periodic in two dimensions with the adsorbate aligned perpendicular to a three-layer slab of MgO (001). The total energy was calculated as the periodic net of Cl2 molecules approached either an oxygen or magnesium site on the surface. The finite thickness of the slab was set such that the interlayer atoms resembled those found in the bulk. The basis set for the solid has an optimized split valence form with 8-61G on Mg and 8-51G on O. The binding energy is reported as a function of Cl2 surface coverage, with a 6-21G* basis set on Cl, in the range from 1:1 to 1:8. At the most dilute coverage (1:8), the Cl2 molecule is bound over an oxygen with a binding energy of 4.1 kcal/mol. The energetics of Cl2 approaching a magnesium show a purely repulsive interaction at all coverages. The interfacial properties are probed with calculations of the band structure, total and projected density of states, density deformation maps, Mulliken analyses, and electrostatic potential maps. The charge density and density deformation maps indicate that the binding of the adsorbate involves very little charge transfer (only approximately 0.03 \e\) between the surface and the molecule. The calculated electrostatic potential and the electric field maps reveal that the interaction is dominated by the electrostatic interaction between the molecule and the surface. A simple electrostatic description of the attractive forces in the binding energy can account for the preference of the adsorbate to bind over oxygen. The total and projected density of states indicate that the higher energy valence states in the slab are dominated by contributions from the 2s and 2p orbitals centered on the oxygens. These states overlap and mix with the states resulting from the 3s and 3p orbitals of the Cl2 net. This mixing occurs to a much smaller extent between chlorine and magnesium orbitals. RP MCCARTHY, MI (reprint author), PACIFIC NW LAB, MOLEC SCI RES CTR, MS K2-18,POB 999, RICHLAND, WA 99352 USA. NR 28 TC 39 Z9 39 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 6010 EP 6017 DI 10.1063/1.462641 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800045 ER PT J AU FELLER, D AF FELLER, D TI APPLICATION OF SYSTEMATIC SEQUENCES OF WAVE-FUNCTIONS TO THE WATER DIMER SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SET SUPERPOSITION ERROR; QUADRATIC CONFIGURATION-INTERACTION; CALCULATED INTERACTION ENERGY; 2 HF MOLECULES; COMPLEXES; JEZIORSKI; SURFACE; PALDUS; CIZEK; SCF AB A systematic series of calculations encompassing a wide range of basis sets and correlated methods has been used to estimate the complete basis set, full CI hydrogen bond strength in the water dimer system. The largest basis set included up through h polarization functions on oxygen and g functions on hydrogen. The complete basis set limit for the self-consistent-field (SCF) interaction energy is estimated to be -3.55 kcal/mol with an accompanying correlation contribution of approximately -1.5 kcal/mol. This leads to an interaction energy of -5.1 kcal/mol, exclusive of vibrational zero-point considerations, and is in good agreement with experimental measurements of -5.4 +/- 0.7 kcal/mol. Inclusion of an approximate adjustment for the basis set superposition error via the Boys/Bernardi counterpoise correction was found to substantially improve agreement with DELTA-E infinity, our estimate of the complete basis set interaction energy, at the both the SCF and correlated levels for basis sets that were lacking in sufficient near-valence diffuse functions. For diffuse-function-augmented basis sets, application of the CP correction was found to sometimes worsen agreement with DELTA-E infinity. RP FELLER, D (reprint author), PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NR 37 TC 943 Z9 947 U1 5 U2 43 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 6104 EP 6114 DI 10.1063/1.462652 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800056 ER PT J AU SHAVIV, R WESTRUM, EF GRUBER, JB BEAUDRY, BJ PALMER, PE AF SHAVIV, R WESTRUM, EF GRUBER, JB BEAUDRY, BJ PALMER, PE TI THERMOPHYSICAL PROPERTIES OF THE LANTHANIDE SESQUISULFIDES .3. DETERMINATION OF SCHOTTKY AND LATTICE HEAT-CAPACITY CONTRIBUTIONS OF GAMMA-PHASE SM2S3 AND EVALUATION OF THE THERMOPHYSICAL PROPERTIES OF THE GAMMA-PHASE LN2S3 SUBSET SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 350-K; TRIHYDROXIDES; GAMMA-ND2S3; MORPHOLOGY; SPECTRA AB We report the experimental heat capacity of gamma-phase Sm2S3 and derived thermophysical properties at selected temperatures. The entropy, enthalpy increments, and Gibbs energy function are 21.50R, 3063R.K, and 11.23R at 298.15 K. The experimental heat capacity is made up of lattice and electronic (Schottky) contributions. The lattice contribution is determined for all gamma-phase lanthanide sesquisulfides (Ln2S3) using the Komada/Westrum model. The difference between the experimental heat capacity and the deduced lattice heat capacity is analyzed as the Schottky contribution. Comparisons are made between the calorimetric Schottky contributions and those determined based on crystal-field electronic energy levels of Ln3+ ions in the lattice and between the Schottky contributions obtained from the empirical volumetric priority approach and from the Komada/Westrum theoretical approach. Predictions for the thermophysical properties of gamma-phase Eu2S3 and gamma-phase Pm2S3 (unavailable for experimental determination) are also presented. C1 UNIV MICHIGAN,DEPT CHEM,ANN ARBOR,MI 48109. SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95192. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. NR 33 TC 14 Z9 14 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 6149 EP 6156 DI 10.1063/1.462857 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800062 ER PT J AU KUROKI, K SPENCE, D DILLON, MA AF KUROKI, K SPENCE, D DILLON, MA TI ENERGY-LOSS SPECTROSCOPY OF CF4 AT NONZERO SCATTERING ANGLES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID ELECTRON-IMPACT; PHOTOELECTRON C1 NATL RES INST POLICE SCI,TOKYO,JAPAN. RP KUROKI, K (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 15 TC 16 Z9 16 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1992 VL 96 IS 8 BP 6318 EP 6319 DI 10.1063/1.462624 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HN268 UT WOS:A1992HN26800081 ER PT J AU SPITZIG, WA CHUMBLEY, LS VERHOEVEN, JD GO, YS DOWNING, HL AF SPITZIG, WA CHUMBLEY, LS VERHOEVEN, JD GO, YS DOWNING, HL TI EFFECT OF TEMPERATURE ON THE STRENGTH AND CONDUCTIVITY OF A DEFORMATION PROCESSED CU-20-PERCENT-FE COMPOSITE SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID WORKED INSITU COMPOSITES; PLATE-LIKE STRUCTURES; CU-NB COMPOSITES; SHAPE INSTABILITIES; MICROSTRUCTURE; RESISTIVITY; ALLOYS AB The high temperature (22-600-degrees-C) properties were evaluated for a Cu-20%Fe composite deformation processed from a powder metallurgy compact. The ultimate tensile strengths decreased with increasing temperature but were appreciably better than those of similarly processed Cu at temperatures up to 450-degrees-C. At 600-degrees-C, the strength of Cu-20%Fe was only slightly better than that of Cu as a result of the pronounced coarsening of the Fe filaments. However, at temperatures of 300 and 450-degrees-C, the strength of Cu-20%Fe is about seven and six times greater, respectively, than that of Cu, as compared to about a two fold advantage at room temperature. Therefore, Cu-20%Fe composites made by deformation processing of powder metallurgy compacts have mechanical properties much superior to those of similarly processed Cu at room temperature and at temperatures up to 450-degrees-C. The pronounced decrease in electrical conductivity of deformation processed Cu 20%Fe as compared to Cu is attributed to the appreciable dissolution of Fe into the Cu matrix which occurred during the fabrication of the starting compacts where temperatures up to 675-degrees-C were used. While the powder metallurgy compacts used for the starting material for deformation processing in this study did not lead to a high conductivity composite, the powder metallurgy approach should still be a viable one if processing temperatures can be reduced further to prevent the dissolution of Fe into the Cu matrix. C1 DRAKE UNIV,DEPT PHYS,DES MOINES,IA 50311. RP SPITZIG, WA (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 22 TC 24 Z9 33 U1 1 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 15 PY 1992 VL 27 IS 8 BP 2005 EP 2011 DI 10.1007/BF01117911 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA HQ667 UT WOS:A1992HQ66700003 ER PT J AU BHATTACHARYA, AK PETROVIC, JJ AF BHATTACHARYA, AK PETROVIC, JJ TI DUCTILE PHASE TOUGHENING AND R-CURVE BEHAVIOR IN A B4C-AL CERMET SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID FRACTURE-TOUGHNESS; CRACK RESISTANCE; STRENGTH; REINFORCEMENTS; CERAMICS; ALUMINA AB The R-curve behaviour of a B4C-Al cermet was studied experimentally using the indentation/strength technique. Microstructural observations clearly indicate that the dominant mechanism contributing towards increasing toughness with crack length is due to bridging of ductile Al phases. It is inferred that ductile toughening, along with toughening due to residual stresses generated upon cooling of the cermet, contribute to this toughening behaviour. Close agreement between experimental results and a simple model is also established. RP BHATTACHARYA, AK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 18 TC 18 Z9 18 U1 1 U2 3 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 15 PY 1992 VL 27 IS 8 BP 2205 EP 2210 DI 10.1007/BF01117938 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA HQ667 UT WOS:A1992HQ66700030 ER PT J AU GOURDIN, WH LASSILA, DH AF GOURDIN, WH LASSILA, DH TI THE MECHANICAL-BEHAVIOR OF PRE-SHOCKED COPPER AT STRAIN RATES OF 10-3-104S-1 AND TEMPERATURES OF 25-400-DEGREES-C SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID RING AB We report the results of our study of the mechanical behavior of pre-shock-loaded oxygen-free electronic (OFE) grade copper. From quasi-static data for samples of 30-mu-m grain size shocked to 10 GPa for 1-mu-s, we derive a value of the thermal component of the mechanical threshold stress (MTS) characteristic of this material that is in good agreement with values in the literature. Using the MTS model for the flow stress of OFE copper, we show that our value of the threshold stress provides an excellent description of split Hopkinson pressure bar data for a strain rate of 2700 s-1. We then calculate the stress-strain behavior of electromagnetically launched expanding rings of 10-mu-m OFE copper previously shocked to 11.5 GPa for 1.6-mu-s, and we find excellent agreement with experimental observations, despite the large strain rate and temperature excursions characteristic of these experiments. We consider the possible influence of differences in the shock pressure and duration between the 10 and 30-mu-m materials on the value of the thermal component of the MTS, and we suggest that experimental scatter implied in the literature is too large to resolve any such differences. The effects of temperature and the limits of plastic flow are discussed briefly within the context of the MTS model. RP GOURDIN, WH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 18 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 15 PY 1992 VL 151 IS 1 BP 11 EP 18 DI 10.1016/0921-5093(92)90176-2 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA HQ705 UT WOS:A1992HQ70500002 ER PT J AU WU, W GORETTA, KC ROUTBORT, JL AF WU, W GORETTA, KC ROUTBORT, JL TI EROSION OF 2014 AL REINFORCED WITH SIC OR AL2O3 PARTICLES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID CERAMIC MATRIX COMPOSITES; DUCTILE METALS; SOLID PARTICLES; ALUMINUM; FRACTURE; MECHANISM AB Solid-particle erosion of 2014 aluminum, 2014 aluminum +20 vol.% SiC particles, and 2014 aluminum + 20 vol.% Al2O3 particles was studied at room temperature. The alloys were tested in the as-cast, annealed, as-quenched, and T6 conditions. Experiments were conducted with Al2O3 or SiC abrasives in vacuum over ranges of abrasive size, velocity and angle of impact. Erosion rates were influenced by reinforcement and heat treatment. Reduced overall and local ductility, attributed to reinforcement or heat treatment, generally caused more rapid erosion of the composites. Data suggest that erosion rate can be minimized by proper microstructural control and heat treatment. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP WU, W (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 42 TC 28 Z9 29 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 15 PY 1992 VL 151 IS 1 BP 85 EP 95 DI 10.1016/0921-5093(92)90185-4 PG 11 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA HQ705 UT WOS:A1992HQ70500011 ER PT J AU PERRY, MD STRICKLAND, D DITMIRE, T PATTERSON, FG AF PERRY, MD STRICKLAND, D DITMIRE, T PATTERSON, FG TI CRLISRALF6 REGENERATIVE AMPLIFIER SO OPTICS LETTERS LA English DT Article ID CHIRPED-PULSE AMPLIFICATION AB The design and performance of a flash-lamp-pumped regenerative amplifier that utilizes the new laser material Cr:LiSrAlF6 is described. The device can be used for tunable and/or short-pulse amplification to the 10-mJ level at a repetition rate of 10 Hz. Using chirped-pulse amplification, we have achieved 8-mJ pulses with a duration of 150 fs. RP PERRY, MD (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,MC L-493,LIVERMORE,CA 94550, USA. RI Strickland, Donna/J-3163-2012 OI Strickland, Donna/0000-0003-2925-5413 NR 15 TC 36 Z9 36 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 15 PY 1992 VL 17 IS 8 BP 604 EP 606 DI 10.1364/OL.17.000604 PG 3 WC Optics SC Optics GA HM730 UT WOS:A1992HM73000018 PM 19794572 ER PT J AU YANG, S CLAUS, H VEAL, BW WHEELER, R PAULIKAS, AP DOWNEY, JW AF YANG, S CLAUS, H VEAL, BW WHEELER, R PAULIKAS, AP DOWNEY, JW TI NEW OBSERVATION OF A PHASE-BOUNDARY IN OXYGEN DEFICIENT YBA2CU3O7-DELTA SINGLE-CRYSTALS SO PHYSICA C LA English DT Article ID SHORT-RANGE ORDER; TEMPERATURE; NONSTOICHIOMETRY; BA2YCU3O7-DELTA AB We have measured the superconducting transition temperature T(c) of oxygen deficient single crystals of YBa2Cu3Ox, where x = 7 - delta in the range 6.5 < x < 6.9, after the crystals were subjected to a series of quenching and aging experiments. A change in the nature of the equilibrium state was observed at temperatures above a concentration dependent threshold temperature T*. We associate T* with the onset of a transition from a vacancy ordered eow temperature (ortho II and/or ortho III) phase to a high temperature ortho I phase. The nature of the vacancy ordering below T* varies with x. We believe that, upon heating above T*, a signigicant concentration of chain fragments develops in normally vacant chains of the ordered structure. When the crystals were quenched from temperatures above T*, and subsequently permitted to anneal at 51-degrees-C, two relaxation processes were found. The two processes have relaxation times differing by about two orders of magnitude. The faster relaxation process is associated with changes in vacancy short-range disorder. The slower process is attributed to restoration of long-range chain vacancy order as misplaced fragments anneal out. T* is determined for different oxygen concentrations and compared to theoretical phase diagram calculations. Electron diffraction measurements on well annealed single crystals with stoichiometries x = 6.50 and 6.65 show that different chain ordered phases (primarily ortho II and ortho III, respectively) exist at each of these compositions. Chain vacancy order is also observed at temperatures above T*. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP YANG, S (reprint author), UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60680, USA. NR 25 TC 45 Z9 47 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 15 PY 1992 VL 193 IS 3-4 BP 243 EP 252 DI 10.1016/0921-4534(92)90725-R PG 10 WC Physics, Applied SC Physics GA HR931 UT WOS:A1992HR93100001 ER PT J AU IZUMI, F JORGENSEN, JD SHIMAKAWA, Y KUBO, Y MANAKO, T PEI, SY MATSUMOTO, T HITTERMAN, RL KANKE, Y AF IZUMI, F JORGENSEN, JD SHIMAKAWA, Y KUBO, Y MANAKO, T PEI, SY MATSUMOTO, T HITTERMAN, RL KANKE, Y TI PRESSURE-INDUCED STRUCTURAL-CHANGES AND CHARGE-TRANSFER IN TL2BA2CUO6+Z SO PHYSICA C LA English DT Article ID NEUTRON POWDER; TC; DIFFRACTION AB Tl2Ba2CuO6+z has negative pressure coefficients of T(c), dT(c)/dp, that vary appreciably with oxygen content. We refined the structure parameters for three samples of Tl2Ba2CuO6+z with T(c)s of 0, 46 and 79 K from time-of-flight neutron powder diffraction data measured at 0-0.622 GPa and room temperature. The lattice parameters of the tetragonal unit cells and the unit-cell volume decreased linearly with increasing pressure. The three samples have similar bulk moduli, K = 82.2-87.6 GPa, which are 29-43% smaller than those of other hole-doped superconductors (118-147 GPa). An axial Cu-O(2) bond, and to a lesser extent an equatorial Cu-O (1) bond, within a [CuO6] octahedron are compressed pronouncedly under high pressure in Tl2Ba2CuO6+z. We propose that this marked shrinkage of the two Cu-O bonds at high pressure is caused by the transfer of electrons from the CuO2 conduction sheets to the charge reservoirs (BaO-TlO-TlO-BaO sheets), lowering the T(c) of this superconductor that is overdoped with holes. This charge-transfer model is consistent with the results of recent Hall-coefficient measurements under high pressure. C1 NEC CORP LTD,FUNDAMENTAL RES LABS,TSUKUBA,IBARAKI 305,JAPAN. NATL RES INST MET,MEGURO KU,TOKYO 153,JAPAN. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. RP IZUMI, F (reprint author), NATL INST RES INORGAN MAT,1-1 NAMIKI,TSUKUBA,IBARAKI 305,JAPAN. RI KUBO, Yoshimi/H-2851-2011 NR 25 TC 28 Z9 28 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 15 PY 1992 VL 193 IS 3-4 BP 426 EP 436 DI 10.1016/0921-4534(92)90966-G PG 11 WC Physics, Applied SC Physics GA HR931 UT WOS:A1992HR93100021 ER PT J AU OLIVIER, BJ SORENSEN, CM TAYLOR, TW AF OLIVIER, BJ SORENSEN, CM TAYLOR, TW TI SCALING DYNAMICS OF AEROSOL COAGULATION SO PHYSICAL REVIEW A LA English DT Article ID DIFFUSION-LIMITED AGGREGATION; CLUSTER-SIZE-DISTRIBUTION; BROWNIAN COAGULATION; COLLOIDAL GOLD; EVOLUTION AB A combination of static and quasielastic light scattering and the theory of scaling solutions to Smoluchowski's equation was used to determine the absolute coagulation rate K'0 and kernel homogeneity lambda of a coagulating liquid-drop aerosol. Droplet sizes ranged from 0.23 to 0.42-mu-m, implying Knudsen numbers in the range 0.26 and 0.14. The temporal evolution of the number concentration M0 and the modal radius r(M) of an assumed zeroth-order log-normal distribution showed near-power-law behavior similar to that predicted by the scaling theory. From the temporal scaling behavior of M0(t) and r(M)(t), the absolute coagulation rate was calculated. The coagulation rates from each method were in good agreement. The rate also agreed well with theory that corrected the Brownian rate, good for the continuum regime, by the average Cunningham correction factor. In addition, the time dependence of the moments M0 and r(M), hence the determination of K'0, was in good agreement with a real-time numerical solution of Smoluchowski's equation for initial conditions analogous to our experimental ones. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. KANSAS STATE UNIV AGR & APPL SCI,DEPT PHYS,MANHATTAN,KS 66506. CLEVELAND STATE UNIV,DEPT PHYS,CLEVELAND,OH 44115. RI Sorensen, Christopher/G-4900-2013 OI Sorensen, Christopher/0000-0002-1980-3394 NR 35 TC 13 Z9 13 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5614 EP 5623 DI 10.1103/PhysRevA.45.5614 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800040 ER PT J AU SHIH, MC BOHANON, TM MIKRUT, JM ZSCHACK, P DUTTA, P AF SHIH, MC BOHANON, TM MIKRUT, JM ZSCHACK, P DUTTA, P TI X-RAY-DIFFRACTION STUDY OF THE SUPERLIQUID REGION OF THE PHASE-DIAGRAM OF A LANGMUIR MONOLAYER SO PHYSICAL REVIEW A LA English DT Article ID ODD-NUMBERED PARAFFINS; ROTATOR PHASE; NORMAL-ALKANES; MOLECULES; FILMS AB Lipid-monolayer isotherms often show a kink that changes to a flat section and back to a kink within a narrow temperature range. In heneicosanoic acid monolayers, along a high-pressure isobar, we have observed a slightly distorted "rotator-I" phase between the known distorted hexagonal and hexagonal phases. Isotherms show a flat section only where this new phase occurs. The diffraction peaks are broader in this phase than in the adjacent phases; this reentrant behavior occurs in the same region of the phase diagram where the viscosity shows anomalous trends (first reported, we believe, by Copeland, Harkins, and Boyd [J. Chem. Phys. 10, 357 (1942)] and thought to indicate a "superliquid" phase). C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37830 USA. RP NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. NR 22 TC 100 Z9 100 U1 1 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5734 EP 5737 DI 10.1103/PhysRevA.45.5734 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800053 ER PT J AU BORISOV, AB BOROVSKIY, AV SHIRYAEV, OB KOROBKIN, VV PROKHOROV, AM SOLEM, JC LUK, TS BOYER, K RHODES, CK AF BORISOV, AB BOROVSKIY, AV SHIRYAEV, OB KOROBKIN, VV PROKHOROV, AM SOLEM, JC LUK, TS BOYER, K RHODES, CK TI RELATIVISTIC AND CHARGE-DISPLACEMENT SELF-CHANNELING OF INTENSE ULTRASHORT LASER-PULSES IN PLASMAS SO PHYSICAL REVIEW A LA English DT Article ID BEAT-WAVE ACCELERATOR; ELECTROMAGNETIC-WAVES; IONIZATION; GENERATION; AMPLIFICATION; RADIATION; ELECTRONS; SYSTEM AB A simple derivation in the Coulomb gauge of the nonlinear Schrodinger equation describing propagation of powerful ultrashort circularly polarized laser pulses in underdense cold inhomogeneous plasmas is presented. Numerical solutions are given for the two-dimensional axisymmetric case for both initially homogeneous plasmas and static preformed plasma columns. These solutions account for (i) diffraction, (ii) refraction arising from variations in the refractive index due to the spatial profile of the electron density distribution, (iii) the relativistic electronic mass shift, and (iv) the charge displacement resulting from the transverse ponderomotive force. The most important spatial modes of propagation corresponding to (1) purely relativistic focusing and (2) the combined action of both the relativistic and charge-displacement mechanisms are described. The latter leads to the formation of stable confined modes of propagation having paraaxially localized regions of high intensity and corresponding paraaxially situated cavitated channels in the electron density. It is further demonstrated that the dynamical solutions of the propagation tend asymptotically to the lowest eigenmodes of the governing nonlinear Schrodinger equation. Finally, the calculations illustrate the dynamics of the propagation and show that the relativistic mechanism promotes the initial concentration of the radiative energy and that the subsequent charge displacement stabilizes this confinement and produces waveguidelike channels. C1 MV LOMONOSOV STATE UNIV,CTR RES COMP,COMP SIMULAT LAB,MOSCOW 119899,USSR. ACAD SCI USSR,INST GEN PHYS,MOSCOW 117942,USSR. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP BORISOV, AB (reprint author), UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60680, USA. NR 41 TC 256 Z9 259 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5830 EP 5845 DI 10.1103/PhysRevA.45.5830 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800066 ER PT J AU FINKENTHAL, M LIPPMANN, S HUANG, LK ZWICKER, A MOOS, HW GOLDSTEIN, WH OSTERHELD, AL AF FINKENTHAL, M LIPPMANN, S HUANG, LK ZWICKER, A MOOS, HW GOLDSTEIN, WH OSTERHELD, AL TI O-SHELL EMISSION OF HEAVY-ATOMS IN AN OPTICALLY THIN TOKAMAK PLASMA SO PHYSICAL REVIEW A LA English DT Article AB Heavy atoms Au (Z = 79), Pb (Z = 82), Bi (Z = 83), and U (Z = 92) have been introduced in the low-density density (n(e) approximately 10(13) cm-3) high-temperature (T(e) greater-than-or-equal-to 1 keV) TEXT tokamak (Fusion Research Center, University of Texas at Austin) plasma. The emission has been measured in the 50-200-angstrom range using a photometrically calibrated, time-resolving grazing-incidence spectrometer. The O-shell ion emission has been identified by comparison with ab initio energy-level calculations and line-intensity predictions of collisional radiative models for various charge states with 5p(6)5d(k) ground-state configurations. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV L,LIVERMORE,CA 94550. HEBREW UNIV JERUSALEM,RACAH INST PHYS,IL-91904 JERUSALEM,ISRAEL. RP FINKENTHAL, M (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. NR 15 TC 2 Z9 3 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 APR 15 PY 1992 VL 45 IS 8 BP 5846 EP 5853 DI 10.1103/PhysRevA.45.5846 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800067 ER PT J AU MENDEL, CW ROSENTHAL, SE SEIDEL, DB AF MENDEL, CW ROSENTHAL, SE SEIDEL, DB TI LOW-PRESSURE RELATIVISTIC ELECTRON FLOW SO PHYSICAL REVIEW A LA English DT Article ID APPLIED MAGNETIC-FIELD; STABILITY PROPERTIES; DIODE; INSULATION AB Most theories of electron flow have involved laminar flows or special flows of a single-orbital type. A general theory of electron flow has been published [C. W. Mendel, Jr., D. B. Seidel, and S. A. Slutz, Phys. Fluids 26, 3628 (1983)]. This theory can be used to make some general statements about these flows, but solutions to particular problems are complex and difficult. By constraining the general theory to flows where the electron pressure normal to the flow direction is small compared to the electromagnetic pressure, finite electron orbits can be taken into account in a general manner. An example of the utility of the theory under this assumption is given. RP MENDEL, CW (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 23 TC 9 Z9 9 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5854 EP 5865 DI 10.1103/PhysRevA.45.5854 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800068 ER PT J AU ALTON, GD SPARROW, RA OLSON, RE AF ALTON, GD SPARROW, RA OLSON, RE TI PLASMA AS A HIGH-CHARGE-STATE PROJECTILE STRIPPING MEDIUM SO PHYSICAL REVIEW A LA English DT Article ID COLLISIONS; TARGET; IONS AB The classical trajectory Monte Carlo model has been used to computationally study the charge-state distributions that result from interactions between a high-energy, multielectron projectile and neutral and fully ionized targets. These studies are designed to determine the properties of a plasma for producing highly stripped ions as a possible alternative to gas and foil strippers that are commonly used to enhance the charge states of energetic ion beams. The results of these studies clearly show that a low-atomic-number, highly ionized plasma can yield higher charge states than a neutral target of the same density. The effect is principally attributable to the reduction in the number of available electron-capture channels. In this article, we compare the charge-state distributions that result during passage of a 20-MeV Pb projectile through neutral gas and fully ionized (singly charged) plasma strippers and estimate the effects of multiple scattering on the quality of the beam. C1 UNIV MISSOURI,ROLLA,MO 65401. RP ALTON, GD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 13 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5957 EP 5963 DI 10.1103/PhysRevA.45.5957 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800078 ER PT J AU BOHN, CL DELAYEN, JR AF BOHN, CL DELAYEN, JR TI CUMULATIVE BEAM BREAKUP IN LINEAR ACCELERATORS WITH PERIODIC-BEAM CURRENT SO PHYSICAL REVIEW A LA English DT Article ID INSTABILITIES AB An analytic formalism of cumulative beam breakup in linear accelerators is developed. This formalism is applied to both low-velocity ion accelerators and high-energy electron accelerators. It includes arbitrary velocity, acceleration, focusing, initial conditions, beam-cavity resonances, finite bunch length, and arbitrary charge distribution within the bunches, and variable cavity geometry and spacing along the accelerator. For both direct-current beams and beams comprised of delta-function bunches, both the steady-state and transient displacements of the beam are calculated, and scaling laws are determined for the transient beam breakup. The steady-state transverse displacement of particles between bunches is also calculated since, if allowed to impinge on the accelerating structures, these particles could cause activation over long periods of continuous-wave operation. The formalism is then applied to high-current ion accelerators by studying the effects of finite bunch length and arbitrary charge distribution within the bunches. The role of focusing in controlling cumulative beam breakup is quantified in each of these cases. Additionally, the effects of random initial conditions and a distribution of deflecting-mode frequencies in the cavities are also quantified. RP BOHN, CL (reprint author), ARGONNE NATL LAB,DIV ENGN PHYS,ARGONNE,IL 60439, USA. NR 29 TC 14 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 5964 EP 5993 DI 10.1103/PhysRevA.45.5964 PG 30 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800079 ER PT J AU SANCHEZ, A SCHARF, R BISHOP, AR VAZQUEZ, L AF SANCHEZ, A SCHARF, R BISHOP, AR VAZQUEZ, L TI SINE-GORDON BREATHERS ON SPATIALLY PERIODIC POTENTIALS SO PHYSICAL REVIEW A LA English DT Article ID DYNAMICS; SOLITONS; PERTURBATIONS; SCATTERING; IMPURITIES; WAVES AB We have carried out an extensive simulation program to study the behavior of sine-Gordon breathers initially at rest in the presence of perturbations that are periodic in space and constant in time. We report here a number of different observed phenomena and the range of the relevant parameters (the ratio of the breather width to the perturbation wavelength and the perturbation magnitude) for which each one of them occurs. We also propose some qualitative explanations valid for certain regimes. C1 UNIV COMPLUTENSE MADRID,FAC CIENCIAS FIS,DEPT FIS TEOR 1,E-28040 MADRID,SPAIN. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP SANCHEZ, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Sanchez, Angel/A-9229-2008; OI Sanchez, Angel/0000-0003-1874-2881; Vazquez, Luis/0000-0003-4054-1197 NR 24 TC 18 Z9 18 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 6031 EP 6037 DI 10.1103/PhysRevA.45.6031 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800084 ER PT J AU STRANDBURG, KJ PESHKIN, MA BOYD, DF CHAMBERS, C OKEEFE, B AF STRANDBURG, KJ PESHKIN, MA BOYD, DF CHAMBERS, C OKEEFE, B TI PHASE-TRANSITIONS IN DILUTE, LOCALLY CONNECTED NEURAL NETWORKS SO PHYSICAL REVIEW A LA English DT Note AB We report numerical studies of the "memory-loss" phase transition in Hopfield-like symmetric neural networks in which the neurons are connected to all other neurons within a local neighborhood (dense, short-range connectivity). The number of connections per neuron K scales as the number of neurons N raised to a power less than 1 (i.e., K approximately N(eta), eta < 1). We use the recently developed Lee-Kosterlitz finite-size scaling technique to determine the critical value of eta below which the first-order phase transition disappears. C1 NORTHWESTERN UNIV,EVANSTON,IL 60208. RP STRANDBURG, KJ (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Peshkin, Michael/B-7604-2009; Peshkin, Michael/D-9449-2016 OI Peshkin, Michael/0000-0001-6126-3320 NR 7 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP 6135 EP 6138 DI 10.1103/PhysRevA.45.6135 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800101 ER PT J AU SCHARF, R KIVSHAR, YS SANCHEZ, A BISHOP, AR AF SCHARF, R KIVSHAR, YS SANCHEZ, A BISHOP, AR TI SINE-GORDON KINK-ANTIKINK GENERATION ON SPATIALLY PERIODIC POTENTIALS SO PHYSICAL REVIEW A LA English DT Article AB A spatially periodic perturbation can lead to a breakup of large-amplitude sine-Gordon breathers into kink and antikink solutions, each oscillating around a minimum of the perturbing potential. This behavior can be understood by studying the effective potential experienced by the breather (bound kink-antikink) or the (free) kink-antikink solution as long as kink and antikink are sufficiently far apart. The resulting kinks and antikinks move independently and nearly radiationlessly in the presence of the perturbation and can travel arbitrarily far for sufficiently large initial kinetic energy. Upon interacting with each other they are strongly affected by the perturbation, lose energy by radiating, and can end in a bound state having the character of a distorted breather. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. UNIV COMPLUTENSE MADRID,FAC CIENCIAS FIS,DEPT FIS TEOR 1,E-28040 MADRID,SPAIN. RP SCHARF, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Sanchez, Angel/A-9229-2008 OI Sanchez, Angel/0000-0003-1874-2881 NR 16 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR 15 PY 1992 VL 45 IS 8 BP R5369 EP R5372 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ038 UT WOS:A1992HQ03800012 ER PT J AU FERNANDO, GW WATSON, RE WEINERT, M AF FERNANDO, GW WATSON, RE WEINERT, M TI HEATS OF FORMATION OF TRANSITION-METAL ALLOYS - FULL-POTENTIAL APPROACH AND THE PT-TI SYSTEM SO PHYSICAL REVIEW B LA English DT Article ID ORBITAL METHOD AB The heats of formation, DELTA-H, of the ordered phases of Pt-Ti are calculated using various approximations. This alloy system was chosen because of the availability of experimental data for DELTA-H for both high- and low-symmetry phases. The difference in the calculated heats of formation between a muffin-tin and a full-potential treatment can be substantial, as much as 0.25 eV/atom. While the total energies of the compounds and the reference elemental metals are all lowered (i.e., increased in binding), the change in DELTA-H depends on which energy is lowered more. For PtTi in the high-symmetry CsCl structure, DELTA-H is reduced, implying that the decrease of the total energy due to the full potential is larger for the elemental reference solids than for the compound. The calculated heats of formation are in accord with the experimental values and the known phase-diagram behavior, i.e., all the low-temperature phases predicted to occur as a function of composition are in fact observed. RP FERNANDO, GW (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 16 TC 14 Z9 14 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8233 EP 8238 DI 10.1103/PhysRevB.45.8233 PG 6 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600001 ER PT J AU SURH, MP LOUIE, SG COHEN, ML AF SURH, MP LOUIE, SG COHEN, ML TI BAND-GAPS OF DIAMOND UNDER ANISOTROPIC STRESS SO PHYSICAL REVIEW B LA English DT Article ID DENSITY-FUNCTIONAL APPROACH; INSULATOR-METAL TRANSITION; STATIC DIELECTRIC MATRICES; 1ST-PRINCIPLES CALCULATION; QUASIPARTICLE ENERGIES; SOLID HYDROGEN; PRESSURE; SEMICONDUCTORS; SILICON; FLUORESCENCE AB Quasiparticle excitation energies are calculated using the GW method for diamond under hydrostatic pressures up to 500 GPa and for one tetragonal configuration under an assumed additional stress in the [001] direction. The self-energy operator is approximated with a model for the static screened Coulomb interaction and a plasmon pole approximation for the dynamically screened interaction. The band gaps increase with hydrostatic pressure. In contrast, the minimum gap decreases upon the application of additional [001] stress, with an extrapolated ultimate metallization pressure of 400 GPa, whereas current experimental extrapolations are for a transition at 700-900 GPa. The lower theoretical value is likely due to excessive anisotropy in the model for the applied stress. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP SURH, MP (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 48 TC 35 Z9 35 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8239 EP 8247 DI 10.1103/PhysRevB.45.8239 PG 9 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600002 ER PT J AU NAKANO, A VASHISHTA, P KALIA, RK YANG, LH AF NAKANO, A VASHISHTA, P KALIA, RK YANG, LH TI PROBING LOCALIZATION AND MOBILITY OF AN EXCESS ELECTRON IN A-SI BY QUANTUM MOLECULAR-DYNAMICS SO PHYSICAL REVIEW B LA English DT Article ID AMORPHOUS-SILICON; TRANSPORT; STATE; DIFFUSION; DENSITY; GAS AB The behavior of an excess electron in a-Si is studied over a wide temperature range using the quantum-molecular-dynamics approach. The electron is found to be localized in a nearly spherical void of radius approximately 3 angstrom, and is surrounded by a ring of eight Si atoms. The simulation results for the electron mobility are in good agreement with the time-of-flight measurements. C1 LOUISIANA STATE UNIV, DEPT PHYS & ASTRON, BATON ROUGE, LA 70803 USA. UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DIV PHYS H, LIVERMORE, CA 94550 USA. RP LOUISIANA STATE UNIV, CONCURRENT COMP LAB MAT SIMULAT, BATON ROUGE, LA 70803 USA. NR 26 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8363 EP 8368 DI 10.1103/PhysRevB.45.8363 PG 6 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600019 ER PT J AU VIGNALE, G SKUDLARSKI, P RASOLT, M AF VIGNALE, G SKUDLARSKI, P RASOLT, M TI CURRENT-DENSITY-FUNCTIONAL THEORY OF THE SURFACE-PROPERTIES OF ELECTRON-HOLE DROPLETS IN A STRONG MAGNETIC-FIELD SO PHYSICAL REVIEW B LA English DT Article ID CHARGE-DENSITY; LIQUID AB We present an application of the current-density functional formalism to a nonuniform many-fermion system in a strong magnetic field. To this end, we construct a current-dependent local ground-state energy functional and derive self-consistent equations for the current density associated with a given density profile. We apply the formalism to the calculation of the surface properties of an electron-hole droplet and we find that the surface tension of the droplet is a rapidly increasing function of the magnetic field. C1 OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. RP UNIV MISSOURI, DEPT PHYS & ASTRON, COLUMBIA, MO 65211 USA. NR 15 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 APR 15 PY 1992 VL 45 IS 15 BP 8494 EP 8497 DI 10.1103/PhysRevB.45.8494 PG 4 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600034 ER PT J AU WU, JZ TRICKEY, SB SABIN, JR BOETTGER, JC AF WU, JZ TRICKEY, SB SABIN, JR BOETTGER, JC TI STRUCTURE, ENERGETICS, AND MOLECULAR-ORDERING TO ATOMIC-ORDERING TRANSITIONS IN HYDROGEN THIN-FILMS SO PHYSICAL REVIEW B LA English DT Article ID METALLIC HYDROGEN; ULTRATHIN FILMS; DILAYER; MONOLAYERS AB One, two, and three layers of hydrogen display a rich variety of features, some intrinsic to ultrathin films, others essentially manifestations of crystalline H behavior. We present calculations, in the framework of local-density-functional theory, of the structure-energy behavior of 22 molecular and atomiclike H films in a variety of hexagonal, square, and rectangular symmetries. The equilibrium phases are molecular in character, subject to some modifications to account for the two-dimensional space group. Thus, the energetically flavored three-layer configuration (the low aspect ratio, c/a < 1, hexagonal system) does not break up-down symmetry (one short and one long interlayer spacing, analogous with a possible linear H-3 geometry) because relaxation to this configuration is incompatible with the drastically different equilibrium intraplanar lattice spacings of the two possible component dilayers. Within the space groups and stackings considered, even the most energetically favored three-layer configuration (hexagonal with overhead stacking) is unbound with respect to the most-bound two-layer and one-layer configurations, an indication that layer-by-layer buildup of crystalline H will involve an intricate sequence of symmetries rather than simple epitaxy. The insulator-metal transition and two versions of the atomic-molecular ordering transition are investigated. For the monolayer transition from (molecular, square) to [monatomic, fcc (100)] ordering, the lattice constants change smoothly, whereas for the dilayer transition from molecularlike (c/a < 1) to atomiclike ordering (c/a > 1) the lattice constants change discontinuously. C1 UNIV FLORIDA,DEPT CHEM,GAINESVILLE,FL 32611. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP WU, JZ (reprint author), UNIV FLORIDA,DEPT PHYS,QUANTUM THEORY PROJECT,GAINESVILLE,FL 32611, USA. NR 34 TC 4 Z9 4 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8610 EP 8622 DI 10.1103/PhysRevB.45.8610 PG 13 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600047 ER PT J AU ORLANDO, TM BURNS, AR JENNISON, DR STECHEL, EB AF ORLANDO, TM BURNS, AR JENNISON, DR STECHEL, EB TI ELECTRONICALLY STIMULATED ADSORBATE DISSOCIATION IN THE PRESENCE OF AN ELECTRONEGATIVE COADSORBATE - (NO2+O) ON PT(111) SO PHYSICAL REVIEW B LA English DT Article ID SURFACE PHOTOCHEMISTRY; NITROGEN-DIOXIDE; ATOMIC OXYGEN; DESORPTION; NO; PHOTODISSOCIATION; PD(111); DISTRIBUTIONS; DEPENDENCE; BR/NI(111) AB The effects of an electronegative coadsorbate on the stimulated dissociation of a chemisorbed molecule are investigated using state-resolved laser-ionization spectroscopy of those dissociation fragments which leave the surface. Specifically, we examine the NO(2-PI(OMEGA) = 1/2,3/2) and O(P-3(J)) fragment energies and yields resulting from electron- (6-350 eV) stimulated dissociation of chemisorbed NO2 as a function of preadsorbed atomic O coverage. The most dramatic effect associated with O coverage (up to THETA(O) = 0.75 monolayer) is a large (a factor of 26) enhancement in the specific NO2 dissociation yield. There is also an O-induced narrowing of the translational energy distributions and a decrease in both the rotational and vibrational energy of the NO fragment. The dissociation threshold of approximately 10 eV, together with lifetime arguments, suggest that the dominant excitation(s) are shallow-valence two-hole excitations. The above observations can be understood in terms of reduced substrate charge-transfer screening of these excitations. In addition, we observe a distinct propensity (> 4:1 at low J) for populating the upper (OMEGA = 3/2) over the lower (OMEGA = 1/2) level of the spin-orbit-split NO(2-PI(OMEGA)) ground state, whereas the spin-orbit population of the O(P-3(J)) fragment is statistical (2J + 1) within experimental error. The O(P-3(J)) yield derives from dissociation of nitro-bound NO2 (N end down); no O(P-3(J)) yield can be associated with side-bonded NO2. C1 SANDIA NATL LABS,DIV 1151,ALBUQUERQUE,NM 87185. RI Stechel, Ellen/B-1253-2012 NR 51 TC 13 Z9 13 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8679 EP 8688 DI 10.1103/PhysRevB.45.8679 PG 10 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600055 ER PT J AU SMITH, AP MACDONALD, AH GUMBS, G AF SMITH, AP MACDONALD, AH GUMBS, G TI QUASI-PARTICLE EFFECTIVE MASS AND ENHANCED G-FACTOR FOR A 2-DIMENSIONAL ELECTRON-GAS AT INTERMEDIATE MAGNETIC-FIELDS SO PHYSICAL REVIEW B LA English DT Note ID HARTREE-FOCK APPROXIMATION; EXCHANGE ENHANCEMENT; INVERSION-LAYERS; SYSTEMS; SUSCEPTIBILITY; ENERGY AB The single-particle self-energy in a Landau quantized two-dimensional electron gas has been evaluated in magnetic fields corresponding to arbitrarily large integer filling factors using the random-phase approximation. Quasiparticle energy separations have been determined for Landau levels near the Fermi level and comparisons are made with values determined from recent activation energy measurements on integral quantum Hall plateaus. Conclusions are drawn concerning the field strengths required for the validity of commonly adopted strong-field approximations. A series of transitions characterized by jumps in the spin polarization is predicted to occur near odd filling factors for sufficiently low densities. C1 INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405. CUNY HUNTER COLL,DEPT PHYS,NEW YORK,NY 10021. RP SMITH, AP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. OI Smith, Arthur/0000-0002-6035-7736 NR 23 TC 61 Z9 61 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 15 BP 8829 EP 8832 DI 10.1103/PhysRevB.45.8829 PG 4 WC Physics, Condensed Matter SC Physics GA HR336 UT WOS:A1992HR33600088 ER PT J AU ZHU, J WANG, XW LOUIE, SG AF ZHU, J WANG, XW LOUIE, SG TI 1ST-PRINCIPLES PSEUDOPOTENTIAL CALCULATIONS OF MAGNETIC IRON SO PHYSICAL REVIEW B LA English DT Article ID GROUND-STATE PROPERTIES; GENERALIZED GRADIENT APPROXIMATION; DENSITY-FUNCTIONAL THEORY; FERROMAGNETIC BCC IRON; TOTAL-ENERGY; ELECTRONIC-PROPERTIES; TRANSITION-METALS; EXCHANGE ENERGY; FCC IRON; SOLIDS AB An ab initio pseudopotential density-functional study of magnetic iron using both the standard local-spin-density approximation and a generalized gradient-expansion approximation is described. The core-valence overlap in this material is found to be important and is treated carefully in the calculation. A mixed-basis approach is employed and the results are comparable with those from all-electron calculations which made use of the same local-spin-density-functional (LSDA) formalism. Results from both all-electron and pseudopotential calculations are found to have significant differences with experimental results. To go beyond LSDA, a recently proposed gradient-expansion exchange and correlation functional is implemented. The calculated results show significantly better agreement with experiment, giving the bec ferromagnetic phase as the stable structure. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. NR 40 TC 63 Z9 63 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 16 BP 8887 EP 8893 DI 10.1103/PhysRevB.45.8887 PG 7 WC Physics, Condensed Matter SC Physics GA HR130 UT WOS:A1992HR13000003 ER PT J AU ABERNATHY, DL MOCHRIE, SGJ ZEHNER, DM GRUBEL, G GIBBS, D AF ABERNATHY, DL MOCHRIE, SGJ ZEHNER, DM GRUBEL, G GIBBS, D TI ORIENTATIONAL EPITAXY AND LATERAL STRUCTURE OF THE HEXAGONALLY RECONSTRUCTED PT(001) AND AU(001) SURFACES SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; REGISTERED PHASE-TRANSITION; SINGLE-CRYSTAL GRAPHITE; X-RAY; COMMENSURATE-INCOMMENSURATE; RESOLUTION FUNCTION; INPLANE STRUCTURE; MONOLAYER XENON; PT(100) SURFACE; CLEAN PT(100) AB We present results of synchrotron-x-ray-scattering studies of the orientational epitaxy exhibited by clean, hexagonally reconstructed Pt(001) and Au(001) surfaces. For the Pt(001) surface, a high-symmetry direction of the hexagonal overlayer is aligned with a high-symmetry direction of the bulk between 1820 and 1685 K. Between 1685 and approximately 1580 K, the relative rotation angle varies continuously from 0-degrees to 0.75-degrees with a one-half-power-law dependence on the reduced temperature. At approximately 1580 K, domains with a rotation angle of 0.8-degrees appear discontinuously, in coexistence with those with a rotation angle of 0.75-degrees. The two rotation angles reach approximately 0.9-degrees and approximately 0.75-degrees for the continuously and discontinuously rotated components, respectively, at 300 K. At all temperatures, the overlayer is incommensurate along both directions of the surface, with weakly temperature-dependent incommensurabilities. The areal density of the Pt(001) overlayer is compressed by approximately 8% with respect to the hexagonal (111) planes in the bulk. In addition, the extent of translational order within the surface layer decreases with decreasing temperature. The Au(001) surface exhibits a strongly discontinuous rotational transformation at approximately 980 K and there is coexistence between rotated and unrotated domains, in agreement with previous measurements. Rotated domains appear at a rotation angle of approximately 0.8-degrees and their number grows with decreasing temperature at the expense of unrotated domains. Our measurements reveal the existence of additional favored rotation angles: one of 0.9-degrees and one that varies smoothly from 0-degrees to 0.5-degrees. The relative domain populations depend on temperature. A mean-field theory of rotational transformations, which accounts for the continuous rotational behavior of the Pt(001) surface, is presented, and it is shown that there are no corrections to mean-field behavior from fluctuations for a rotational transformation. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP ABERNATHY, DL (reprint author), MIT,ELECTR RES LAB,CAMBRIDGE,MA 02139, USA. RI Abernathy, Douglas/A-3038-2012 OI Abernathy, Douglas/0000-0002-3533-003X NR 63 TC 57 Z9 57 U1 0 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1992 VL 45 IS 16 BP 9272 EP 9291 DI 10.1103/PhysRevB.45.9272 PG 20 WC Physics, Condensed Matter SC Physics GA HR130 UT WOS:A1992HR13000048 ER PT J AU FULLER, GM SCHRAMM, DN AF FULLER, GM SCHRAMM, DN TI LATE-PHASE-TRANSITION-INDUCED FLUCTUATIONS IN THE COSMIC NEUTRINO DISTRIBUTION AND THE FORMATION OF STRUCTURE IN THE UNIVERSE SO PHYSICAL REVIEW D LA English DT Article ID BROKEN LEPTON NUMBER; SOLAR NEUTRINOS; FALSE VACUUM; MATTER; OSCILLATIONS; GENERATION; GALAXIES; SCALE AB We show that late-time (T(c) less-than-or-equal-to 1 eV) cosmic vacuum phase transitions which induce separation of phases and which involve a discontinuity in neutrino properties (e.g., mass) across phase boundaries could give rise to spatial inhomogeneities in the distribution of neutrinos. The nucleation physics of the phase transition would determine the spatial scale of the fluctuations. These density perturbations would be born in the nonlinear regime and could have masses in the range of 10(6)M.-10(13)M.. If the fluctuations are shells, as expected, and there is gravitational modification of the original phase-transition nucleation scale then the upper limit on their masses could be considerably larger (almost-equal-to 10(18)M.), possibly encompassing the largest structures in the Universe. The motivation for this work stems, in part, from the possibility that future experiments (i.e., solar neutrino experiments) may suggest new, low-energy-scale weak-interaction phenomena, such as neutrino flavor mixing. C1 UNIV CHICAGO,DEPT PHYS & ASTRON,CHICAGO,IL 60637. FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,DEPT ASTROPHYS,CHICAGO,IL 60637. RP FULLER, GM (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093, USA. NR 51 TC 16 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2595 EP 2600 DI 10.1103/PhysRevD.45.2595 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500004 ER PT J AU FRIEMAN, JA JAFFE, AH AF FRIEMAN, JA JAFFE, AH TI COSMOLOGICAL CONSTRAINTS ON PSEUDO NAMBU-GOLDSTONE BOSONS SO PHYSICAL REVIEW D LA English DT Article ID SUPERSTRING MODELS; INVISIBLE AXIONS; COSMIC STRINGS; EARLY-UNIVERSE; DOMAIN-WALLS; EVOLUTION; SN-1987A; TEXTURE AB Particle-physics models with pseudo Nambu-Goldstone bosons (PNGB's) are characterized by two mass scales: a global spontaneous-symmetry-breaking scale f and a soft (explicit) symmetry-breaking scale LAMBDA. We investigate general model-insensitive constraints on this two-dimensional parameter space arising from the cosmological and astrophysical effects of PNGB's. In particular, we study constraints arising from vacuum misalignment and thermal production of PNGB's, topological defects, and the cosmological effects of PNGB decay products, as well as astrophysical constraints from stellar PNGB emission. Bounds on the Peccei-Quinn axion scale, 10(10) GeV less-than-or-similar-to f(PQ) less-than-or-similar-to 10(10)-10(12) GeV, emerge as a special case, where the soft breaking scale is fixed at LAMBDA(QCD) congruent-to 100 MeV. C1 UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP FRIEMAN, JA (reprint author), FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,NASA,BATAVIA,IL 60510, USA. RI Jaffe, Andrew/D-3526-2009 NR 45 TC 14 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2674 EP 2684 DI 10.1103/PhysRevD.45.2674 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500013 ER PT J AU ANDERSON, GW HALL, LJ AF ANDERSON, GW HALL, LJ TI ELECTROWEAK PHASE-TRANSITION AND BARYOGENESIS SO PHYSICAL REVIEW D LA English DT Article ID SMALL-FLUCTUATION DETERMINANT; BARYON-NUMBER VIOLATION; FINITE TEMPERATURE; SYMMETRY BEHAVIOR; EARLY UNIVERSE; FALSE VACUUM; ASYMMETRY; GAUGE; COMPUTATION; SPHALERONS AB We give an analytic treatment of the one-Higgs-doublet, electroweak phase transition which demonstrates that the phase transition is first order. The phase transition occurs by the nucleation of thin-walled bubbles and completes as a temperature where the order parameter < phi > T is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon-number violation is an exponentially sensitive function of < phi > T. In very minimal extensions of the standard model it is quite easy to increase < phi > T so that anomalous baryon-number violation is suppressed after the completion of the phase transition. Hence, baryogenesis at the electroweak phase transition is tenable in minimal extensions of the standard model with one Higgs doublet. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. OI Anderson, Greg/0000-0003-0346-7258 NR 39 TC 279 Z9 279 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2685 EP 2698 DI 10.1103/PhysRevD.45.2685 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500014 ER PT J AU LEE, KY NAIR, VP WEINBERG, EJ AF LEE, KY NAIR, VP WEINBERG, EJ TI BLACK-HOLES IN MAGNETIC MONOPOLES SO PHYSICAL REVIEW D LA English DT Article ID ZERO-ORDER STRUCTURE; MILLS-HIGGS SYSTEM; WORMHOLE SOLUTIONS AB We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs-field vacuum expectation value v is less than or equal to a critical value v(cr), which is of the order of the Planck mass. In the limiting case, the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For v < v(cr), we find additional solutions which are singular at r = 0, but which have this singularity hidden within a horizon. These have nontrivial matter fields outside the horizon, and may be interpreted as small black holes lying within a magnetic monopole. The nature of these solutions as a function of v and of the total mass M and their relation to the Reissner-Nordstrom solutions are discussed. C1 FERMI NATL ACCELERATOR LAB,THEORY GRP,BATAVIA,IL 60510. FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,NASA,BATAVIA,IL 60510. RP LEE, KY (reprint author), COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027, USA. RI Lee, Kimyeong/K-1070-2013 OI Lee, Kimyeong/0000-0003-3451-1514 NR 18 TC 155 Z9 155 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2751 EP 2761 DI 10.1103/PhysRevD.45.2751 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500020 ER PT J AU DOWKER, F GREGORY, R TRASCHEN, J AF DOWKER, F GREGORY, R TRASCHEN, J TI EUCLIDEAN BLACK-HOLE VORTICES SO PHYSICAL REVIEW D LA English DT Article ID COSMIC STRINGS; BARYON NUMBER; STABILITY; FIELD AB We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an Abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the back reaction shows that the effect of the vortex is to cut a slice out of the Euclidean Schwarzschild geometry. The consequences of these solutions for black-hole thermodynamics are discussed. C1 UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV MASSACHUSETTS,DEPT PHYS,AMHERST,MA 01002. RP DOWKER, F (reprint author), FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,NASA,POB 500,BATAVIA,IL 60510, USA. NR 25 TC 40 Z9 40 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2762 EP 2771 DI 10.1103/PhysRevD.45.2762 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500021 ER PT J AU PAZ, JP SINHA, S AF PAZ, JP SINHA, S TI DECOHERENCE AND BACK REACTION IN QUANTUM COSMOLOGY - MULTIDIMENSIONAL MINISUPERSPACE EXAMPLES SO PHYSICAL REVIEW D LA English DT Article ID LOGICAL REFORMULATION; EARLY UNIVERSE; MECHANICS; SPACETIME; ANISOTROPY; EMERGENCE; ENVIRONMENT; DISSIPATION; KINEMATICS; GRAVITY AB We study some aspects of the semiclassical limit of quantum cosmology using multidimensional minisuperspace models with scalar perturbations. Regarding the minisuperspace coordinates as the "relevant" degrees of freedom and the scalar field modes as the "irrelevant" ones, we study the reduced density matrix to analyze the existence of decoherence and correlations. For a Bianchi type-I model we show that the correlations predicted from the peak of the Wigner function associated with a decohered WKB branch are the same as those determined by the semiclassical Einstein equations. We discuss the renormalization of the divergent quantities that appear in the calculation and show that usual dimensional-regularization techniques only allow us to regulate the phase of the reduced density matrix. This illustrates the fundamental difference that exists between the divergences found in the back-reaction equations and the ones that affect the quantum coherence. We analyze a class of models with adiabatic behavior in which there are no problematic divergences affecting the decoherence factor. Finally, we discuss some aspects of the relation between our approach, based on the use of the reduced density matrix, and that formulated in terms of spacetime histories. C1 UNIV MARYLAND,DEPT PHYS & ASTRON,COLLEGE PK,MD 20742. RP PAZ, JP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Paz, Juan/C-5947-2008 NR 58 TC 37 Z9 37 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1992 VL 45 IS 8 BP 2823 EP 2842 DI 10.1103/PhysRevD.45.2823 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HP205 UT WOS:A1992HP20500029 ER PT J AU SURERUS, KK OERTLING, WA FAN, CL GURBIEL, RJ EINARSDOTTIR, O ANTHOLINE, WE DYER, RB HOFFMAN, BM WOODRUFF, WH FEE, JA AF SURERUS, KK OERTLING, WA FAN, CL GURBIEL, RJ EINARSDOTTIR, O ANTHOLINE, WE DYER, RB HOFFMAN, BM WOODRUFF, WH FEE, JA TI REACTION OF CYANIDE WITH CYTOCHROME-BA3 FROM THERMUS-THERMOPHILUS - SPECTROSCOPIC CHARACTERIZATION OF THE FE(II)A3-CN-BULLET-CU(II)B-CN COMPLEX SUGGESTS 4 N-14 ATOMS ARE COORDINATED TO CU(B) SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE CYANIDE COMPLEX ID BOVINE SUPEROXIDE-DISMUTASE; NUCLEAR DOUBLE-RESONANCE; C-OXIDASE; COPPER PROTEINS; SPIN-RESONANCE; RAMAN; BINDING; SITES; IRON AB Cytochrome ba3 from Thermus thermophilus reacts slowly with excess HCN at pH 7.4 to create a form of the enzyme in which Cu(A), cytochrome b, and Cu(B) remain oxidized, while cytochrome a3 is reduced by one electron, presumably with the formation of cyanogen. We have examined this form of the enzyme by UV-visible, resonance Raman, EPR, and electron nuclear double resonance spectroscopies in conjunction with permutations of C-13- and N-15-labeled cyanide. The results support a model in which one CN- binds through the carbon atom to ferrous a3, supporting a low-spin (S = 0) configuration on the Fe; bridging by this cyanide to the Cu(B) is weak or absent. Four N-14 atoms, presumably donated by histidine residues of the protein. provide a strong equatorial ligand field about Cu(B); a second CN- is coordinated through the carbon atom to Cu(B) in an axial position. C1 UNIV CALIF LOS ALAMOS SCI LAB,ISOTOPE & STRUCT CHEM GRP,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,CHEM & LASER SCI GRP,LOS ALAMOS,NM 87545. NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. JAGIELLONIAN UNIV,INST MOLEC BIOL,PL-31007 KRAKOW,POLAND. MED COLL WISCONSIN,NATL BIOMED ESR CTR,MILWAUKEE,WI 53226. FU NHLBI NIH HHS [HL13531]; NIDDK NIH HHS [DK36263]; NIGMS NIH HHS [GM35342] NR 30 TC 52 Z9 53 U1 0 U2 5 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1992 VL 89 IS 8 BP 3195 EP 3199 DI 10.1073/pnas.89.8.3195 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP043 UT WOS:A1992HP04300007 PM 1314380 ER PT J AU WANG, D FANG, H CANTOR, CR SMITH, CL AF WANG, D FANG, H CANTOR, CR SMITH, CL TI A CONTIGUOUS NOT-I RESTRICTION MAP OF BAND Q22.3 OF HUMAN CHROMOSOME-21 SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID SOMATIC-CELL GENETICS; ALZHEIMERS-DISEASE; DOWNS-SYNDROME; DNA-SEQUENCES; DELETION; REGION; EXPRESSION; UNIQUE; PROBES; LOCUS AB A contiguous high-resolution Not I restriction map of the distal region of the long arm of human chromosome 21 was constructed by three strategies: linking clones to identify adjacent pieces of DNA, partial digestion to identify neighboring fragments, and cell line polymorphisms to prove identity or adjacency of DNA fragments. Twenty-nine single-copy DNA probes and rive linking clone probes were used to determine the order of 30 Not I fragments, covering 10 megabases of DNA in band q22.3. Smaller Not I fragments occur preferentially in this region, suggesting that band q22.3 is unusually rich in genes, since Not I sites occur almost exclusively in CpG islands. Comparison of the physical map and genetic maps in this region reveals a 10-fold higher than average recombination frequency. C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720. OI Smith, Cassandra/0000-0002-0346-8907 NR 50 TC 23 Z9 23 U1 0 U2 0 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1992 VL 89 IS 8 BP 3222 EP 3226 DI 10.1073/pnas.89.8.3222 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP043 UT WOS:A1992HP04300013 PM 1565613 ER PT J AU OSTRANDER, EA JONG, PM RINE, J DUYK, G AF OSTRANDER, EA JONG, PM RINE, J DUYK, G TI CONSTRUCTION OF SMALL-INSERT GENOMIC DNA LIBRARIES HIGHLY ENRICHED FOR MICROSATELLITE REPEAT SEQUENCES SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE MARKER-SELECTED LIBRARIES; CA REPEATS; SEQUENCE-TAGGED SITES; GENETIC MAPPING; DOG GENOME ID POLYMERASE CHAIN-REACTION; SITE-SPECIFIC MUTAGENESIS; PHENOTYPIC SELECTION; EUKARYOTIC GENOMES; THERMUS-AQUATICUS; POLYMORPHISMS; GENE AB We describe an efficient method for the construction of small-insert genomic libraries enriched for highly polymorphic, simple sequence repeats. With this approach, libraries in which 40-50% of the members contain (CA)n repeats are produced, representing an almost-equal-to 50-fold enrichment over conventional small-insert genomic DNA libraries. Briefly, a genomic library with an average insert size of less than 500 base pairs was constructed in a phagemid vector. Amplification of this library in a dut ung strain of Escherichia coli allowed the recovery of the library as closed circular single-stranded DNA with uracil frequently incorporated in place of thymine. This DNA was used as a template for second-strand DNA synthesis, primed with (CA)n or (TG)n oligonucleotides, at elevated temperatures by a thermostable DNA polymerase. Transformation of this mixture into wild-type E. coli strains resulted in the recovery of primer-extended products as a consequence of the strong genetic selection against single-stranded uracil-containing DNA molecules. In this manner, a library highly enriched for the targeted microsatellite-containing clones was recovered. This approach is widely applicable and can be used to generate marker-selected libraries bearing any simple sequence repeat from cDNAs, whole genomes, single chromosomes, or more restricted chromosomal regions of interest. C1 HARVARD UNIV,SCH MED,HOWARD HUGHES MED INST,DEPT GENET,BOSTON,MA 02115. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR HUMAN GENOME,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MOLEC & CELLULAR BIOL,BERKELEY,CA 94720. OI Ostrander, Elaine/0000-0001-6075-9738 FU NIEHS NIH HHS [ESO1896] NR 22 TC 200 Z9 238 U1 2 U2 19 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1992 VL 89 IS 8 BP 3419 EP 3423 DI 10.1073/pnas.89.8.3419 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP043 UT WOS:A1992HP04300054 PM 1314388 ER PT J AU JACKSON, JD AF JACKSON, JD TI ARE THE STRAY 60-HZ ELECTROMAGNETIC-FIELDS ASSOCIATED WITH THE DISTRIBUTION AND USE OF ELECTRIC-POWER A SIGNIFICANT CAUSE OF CANCER SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE LEUKEMIA; NONIONIZING RADIATION AB The putative causal relation between ambient low-frequency (50 or 60 Hz) electromagnetic fields (necessarily present in living and working environments because of our ever increasing use of electrical devices) and cancer, especially leukemia, can be tested on the large scale by examining historical data on the growth of the generation and consumption of electric power since 1900 and corresponding data on cancer death and incidence rates. The United States per capita generation and residential consumption of electric power have grown roughly exponentially since 1900; total per capita generation has increased by a factor of 10 since 1940, and per capita residential consumption has increased by a factor of 20 in the same period. The ubiquitous stray fields from power distribution lines and internal and external wiring in buildings have grown in the same proportions. In contrast to the explosive increase in the generation and use of electricity, the age-adjusted cancer death rate for the population as a whole shows only a slight rise since 1900. When respiratory cancers (largely caused by tobacco use) are subtracted, the remaining death rate has actually fallen since 1940. That the death rate may have fallen because of better diagnosis and treatment, despite a rising incidence rate, is not substantiated, especially for leukemia, including childhood leukemia, where the incidence rate has been constant or declining slightly for the past 25 yr. The absence of any appreciable change in the national cancer incidence rates during a period in which residential use of electric power has increased dramatically shows that the associated stray 50- or 60-Hz electromagnetic fields pose no significant hazard to the average individual. C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. RP JACKSON, JD (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 9 TC 28 Z9 28 U1 0 U2 1 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1992 VL 89 IS 8 BP 3508 EP 3510 DI 10.1073/pnas.89.8.3508 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP043 UT WOS:A1992HP04300072 PM 1565645 ER PT J AU PRIVE, GG MILBURN, MV TONG, L DEVOS, AM YAMAIZUMI, Z NISHIMURA, S KIM, SH AF PRIVE, GG MILBURN, MV TONG, L DEVOS, AM YAMAIZUMI, Z NISHIMURA, S KIM, SH TI X-RAY CRYSTAL-STRUCTURES OF TRANSFORMING P21 RAS MUTANTS SUGGEST A TRANSITION-STATE STABILIZATION MECHANISM FOR GTP HYDROLYSIS SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MURINE SARCOMA-VIRUS; C-HA-RAS; GENE-PRODUCT; MACROMOLECULAR CRYSTALLOGRAPHY; TRIPHOSPHATE CONFORMATION; BIOCHEMICAL-PROPERTIES; NUCLEOTIDE-SEQUENCE; WEISSENBERG CAMERA; ONCOGENIC RAS-P21; CATALYTIC DOMAIN AB RAS genes isolated from human tumors often have mutations at positions corresponding to amino acid 12 or 61 of the encoded protein (p21), while retroviral ras-encoded p21 contains substitutions at both positions 12 and 59. These mutant proteins are deficient in their GTP hydrolysis activity, and this loss of activity is linked to their transforming potential. The crystal structures of the mutant proteins are presented here as either GDP-bound or GTP-analogue-bound complexes. Based on these structures, a mechanism for the p21 GTPase reaction is proposed that is consistent with the observed structural and biochemical data. The central feature of this mechanism is a specific stabilization complex formed between the Gln-61 side-chain and the pentavalent gamma-phosphate of the GTP transition state. Amino acids other than glutamine at position 61 cannot stabilize the transition state, and amino acids larger than glycine at position 12 would interfere with the transition-state complex. Thr-59 disrupts the normal position of residue 61, thus preventing its participation in the transition-state complex. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NATL CANC CTR,RES INST,TOKYO 104,JAPAN. RI Prive, Gilbert/A-3039-2008 FU NCI NIH HHS [CA 45593] NR 36 TC 115 Z9 115 U1 0 U2 6 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1992 VL 89 IS 8 BP 3649 EP 3653 DI 10.1073/pnas.89.8.3649 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP043 UT WOS:A1992HP04300101 PM 1565661 ER PT J AU DEMAREE, JD WAS, GS SORENSEN, NR AF DEMAREE, JD WAS, GS SORENSEN, NR TI CHEMICAL AND STRUCTURAL EFFECTS OF PHOSPHORUS ON THE CORROSION BEHAVIOR OF ION-BEAM MIXED FE-CR-P ALLOYS SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID METALLOID METALLIC GLASSES; AMORPHOUS IRON-ALLOYS; PASSIVITY; RESISTANCE; CHEMISTRY; AUGER AB An experimental program was conducted to determine the mechanisms by which phosphorus affects the corrosion and passivation behavior of Fe-Cr-P alloys. To identify separately the effects of structure and chemistry on the corrosion behavior, thin films of Fe-10Cr-xP (0 less-than-or-equal-to x less-than-or-equal-to 35 at.%) were prepared by ion beam mixing. Films with a phosphorus content greater than approximately 20 at.% were found to be entirely amorphous. Devitrification of the amorphous phase was accomplished by heating the samples to 450-degrees-C in an inert environment. Standard polarization tests of the alloys in sulfuric acid (with and without Cl-) indicated that the films containing phosphorus were more corrosion resistant than Fe-10Cr, at both active and passive potentials. There was a monotonic relationship between the amount of phosphorus in the alloy and the corrosion resistance, with the open-circuit corrosion rate of Fe-10Cr-35P nearly four orders of magnitude lower than that of Fe-10Cr. Devitrification of the alloys had no significant effect on the corrosion rate, indicating that the primary effect of phosphorus is chemical in nature, and not structural. The passive oxides were depth-profiled using X-ray photoelectron spectroscopy, which indicated that phosphorus was a primary constituent, as phosphate. The presence of phosphate in the passive oxides reduced the overall corrosion rate directly, by suppressing anodic dissolution. The presence of phosphorus did enhance chromium enrichment in the oxide, but that was not thought to be the primary mechanism by which phosphorus increased the corrosion resistance. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP DEMAREE, JD (reprint author), UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109, USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 6 EP 12 DI 10.1016/0257-8972(92)90206-P PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900003 ER PT J AU HOU, P CHIA, V BROWN, I AF HOU, P CHIA, V BROWN, I TI DISTRIBUTION OF ION-IMPLANTED YTTRIUM IN CR2O3 SCALES AND IN THE UNDERLYING NI-25WT-PERCENT-CR ALLOY SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID OXIDATION; METALS AB Implantation of yttrium and other reactive metals has been known to have significant effects on the oxidation behavior of Cr2O3-forming alloys. The oxide growth rate decreases by nearly a factor of ten, and the adhesion of oxide scales to alloys is greatly improved. To understand better the mechanisms by which these elements affect oxidation, it is important to know whether or not they are present in the metal ahead of the oxide layer. In this study, the diffusivity of implanted yttrium in an Ni-25wt.%Cr alloy and its distribution in the oxide scale after different oxidation times were evaluated using secondary ion mass spectroscopy. It was found that only 17 ppm yttrium was left in the alloy after just 20 min of oxidation at 1000-degrees-C. The implanted yttrium remained concentrated at the oxide-gas interface as the oxide thickened with time. Within the oxide layer, the yttrium concentration progressively dropped to zero at the scale-alloy interface. These results are discussed in relation to several important mechanisms proposed for the beneficial effects of reactive element additions on scale adhesion. C1 CHARLES EVANS & ASSOCIATES,REDWOOD CITY,CA 94063. RP HOU, P (reprint author), LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 17 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 73 EP 78 DI 10.1016/0257-8972(92)90217-X PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900014 ER PT J AU KUSTAS, FM MISRA, MS WEI, R WILBUR, PJ KNAPP, JA AF KUSTAS, FM MISRA, MS WEI, R WILBUR, PJ KNAPP, JA TI HIGH-TEMPERATURE NITROGEN IMPLANTATION OF TI-6AL-4V .1. MICROSTRUCTURE CHARACTERIZATION SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID ION-IMPLANTATION AB A high temperature ion implantation method, employing a high current density beam (e.g. 500-mu-A cm-2) of nitrogen ions was used to modify the near-surface microstructure of Ti-6Al-4V. A systematic study was performed with nitrogen implantation at temperatures from 400-degrees-C to more than 1000-degrees-C, and to a range of doses from (0.1-1.0) x 10(18) N2+-N2+-N+ cm-2. Microstructure characterization by Rutherford backscattering spectroscopy (RBS) and glancing incidence X-ray diffraction (GID) was performed to determine the nitrogen distribution and compound formation. RBS analysis showed enhanced nitrogen penetrations for the 800-degrees-C and 1000-degrees-C implantations compared with implantations at temperatures less than 600-degrees-C. GID indicated TiN and Ti2N concentrations were the greatest for the 800-degrees-C implantation treatment. C1 COLORADO STATE UNIV,FT COLLINS,CO 80523. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP KUSTAS, FM (reprint author), MARTIN MARIETTA AEROSP CO,ASTRONAUT GRP,DENVER,CO 80201, USA. NR 13 TC 24 Z9 24 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 100 EP 105 DI 10.1016/0257-8972(92)90221-U PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900018 ER PT J AU RAO, GR LEE, EH CHIN, BA AF RAO, GR LEE, EH CHIN, BA TI ION-IMPLANTATION EFFECTS ON FATIGUE PROPERTIES OF FE-13CR-15NI ALLOYS SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID CRACK INITIATION; NICKEL; LIFE AB Bend fatigue tests and microhardness measurements were carried out on eight complex Fe-13Cr-15Ni alloys based on the composition Fe-13Cr-15Ni-2Mo-2Mn-0.2Ti-0.8Si-0.06C, implanted simultaneously with 400 keV boron and 550 keV nitrogen ions to a dose of 2.3 x 10(16) ions cm-2 for each ion. For all eight alloys, the dual implantation improved the surface hardness but reduced the fatigue life. Optical microscopy revealed that the implantation suppressed surface slip band formation and slip band crack initiation. Transmission electron microscopy was used to characterize the near-surface microstructures. It is evident that the suppression of slip band formation promoted grain boundary cracking to relieve stresses developed in the grains, thus leading to a reduced fatigue life. A similar study of four simple alloys based on the ternary Fe-13Cr-15Ni indicated that while dual implantation improved fatigue life, up to 250% in one case, triple implantation with boron, nitrogen and carbon ions reduced fatigue life, again owing to a shift to grain boundary cracking. Improvement in fatigue properties of polycrystalline alloys by multiple ion implantation is thus limited by the presence of grain boundaries. C1 AUBURN UNIV,MAT ENGN PROGRAM,AUBURN,AL 36849. RP RAO, GR (reprint author), OAK RIDGE NATL LAB,POB 2008,BLDG 5500,OAK RIDGE,TN 37831, USA. NR 18 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 112 EP 117 DI 10.1016/0257-8972(92)90223-W PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900020 ER PT J AU PAWEL, JE MCHARGUE, CJ ROMANA, LJ WERT, JJ AF PAWEL, JE MCHARGUE, CJ ROMANA, LJ WERT, JJ TI ION-BEAM-ENHANCED ADHESION OF IRON FILMS TO SAPPHIRE SUBSTRATES SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID IMPLANTATION; INTERFACES AB The effect of implantation of different ion species on the adhesion of iron films to sapphire substrates was investigated. The implantation energies were adjusted to ensure that the ion concentration profiles, damage profiles, and recoil distributions were the same for each species. For all implantations, the peak ion concentration was at the film-substrate interface. The adhesion of the films was measured by a pull test and a scratch test. For a fluence of 1 x 10(15) ions cm-2, implantation of chromium (300 keV) and iron (320 keV) increased the bond strength whereas implantation of nickel (340 keV) did not. The effect is proposed to be due to changes in the interfacial energy resulting from the presence of the ion species at the interface. Only a narrow zone is affected; the mixing at the interface is less than 10 nm. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. VANDERBILT UNIV,NASHVILLE,TN 37235. RP PAWEL, JE (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 26 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 129 EP 132 DI 10.1016/0257-8972(92)90226-Z PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900023 ER PT J AU WEI, R WILBUR, PJ ERDEMIR, A KUSTAS, FM AF WEI, R WILBUR, PJ ERDEMIR, A KUSTAS, FM TI THE EFFECTS OF BEAM ENERGY AND SUBSTRATE-TEMPERATURE ON THE TRIBOLOGICAL PROPERTIES OF HARD-CARBON FILMS ON ALUMINUM SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID DIAMOND AB Hard-carbon films were applied on flat 6061-T6 aluminum substrates using a broad-beam ion source operating on methane and producing carbonaceous ions with energies that varied from 250 to 1050 eV. Films were evaluated using a reciprocating alumina ball-on-flat sliding wear tester operating in an ambient air test environment. The films facilitated substantial reductions in friction coefficients to 0.08-0.2 from 0.4-0.7 for uncoated aluminum. At a sufficiently high normal load. the films failed and friction coefficients increased to the higher range. The best film caused this critical normal load to increase from less than 0.1 N for untreated aluminum to greater than 30 N. A near-optimal beam ion energy (450 eV) was identified for good quality films. At lower energies (e.g. 250 eV) films were discontinuous, while at higher energies (e.g. 1050 eV) high sputter rates limited film growth. When an aluminum flat was held at low temperature during processing, the films were smooth and adhered well, but they became rougher and adhered poorly as the temperature was increased above approximately 300-degrees-C. C1 ARGONNE NATL LAB,TRIBOL PROGRAM,ARGONNE,IL 60439. MARTIN MARIETTA AEROSP CO,DENVER,CO 80201. RP WEI, R (reprint author), COLORADO STATE UNIV,DEPT MECH ENGN,FT COLLINS,CO 80523, USA. NR 10 TC 44 Z9 48 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 139 EP 145 DI 10.1016/0257-8972(92)90228-3 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900025 ER PT J AU HSIEH, JH WU, W ERCK, RA FENSKE, GR SU, YY MAREK, M AF HSIEH, JH WU, W ERCK, RA FENSKE, GR SU, YY MAREK, M TI NB-CR ALLOY COATINGS PRODUCED BY ION-BEAM-ASSISTED DEPOSITION SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID FILMS; METAL AB Nb-Cr alloy coatings were deposited onto 316L stainless steel using a dual-crucible electron beam evaporation source, together with simultaneous bombardment by 250 eV argon ions. Through control of alloy composition and the atomic ratio [Ar+]/[Nb + Cr], a dense and column-free coating was obtained. This coating contained 50 at.% Cr and was deposited under the bombardment of 250 eV Ar+ at an ion-to-metal-atom ratio of 0.68. All of the coated samples showed better corrosion behavior than did the uncoated samples. Overall, the Nb-30%Cr coating appears to be the most corrosion resistant and behaves similarly to pure niobium. C1 GEORGIA INST TECHNOL,SCH MAT ENGN,ATLANTA,GA 30332. RP HSIEH, JH (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 9 TC 11 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 212 EP 216 DI 10.1016/0257-8972(92)90240-B PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900037 ER PT J AU LEE, YC LEE, EH MANSUR, LK AF LEE, YC LEE, EH MANSUR, LK TI HARDNESS AND WEAR PROPERTIES OF BORON-IMPLANTED POLY(ETHERETHERKETONE) AND POLY-ETHER-IMIDE SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID INDENTATION; COMPOSITES AB The effects of boron beam irradiation on the hardness, friction, and wear of polymer surfaces were investigated. Typical high-performance thermoplastics, poly(ether-ether-ketone) (PEEK) and a poly-ether-imide (Ultem) were studied after 200 keV boron ion beam treatment at ambient temperature to doses of 2.3 x 10(14), 6.8 x 10(14), and 2.2 x 10(15) ions cm-2. The hardnesses of pristine and boron-implanted materials were characterized by a conventional Knoop method and a load depth sensing nanoindentation technique. Both measurements showed a significant increase in hardness with increasing dose. The increase in hardness was also found to depend on the penetration depth of the diamond indenter. Wear and friction properties were characterized by a reciprocating sliding friction tester with an SAE 52100 high-carbon, chrome steel ball at 0.5 and 1 N normal loads. Wear and frictional properties varied in a complex fashion with polymer type and dose, but not much with normal load. A substantial reduction in friction coefficient was observed for PEEK at the highest dose but no reduction was observed for Ultem. The wear damage was substantially reduced at the highest dose for both Ultem and PEEK. For the system studied, the highest dose, 2.2 x 10(15) ions cm-2, appears to be optimum in improving wear resistance for both PEEK and Ultem. RP LEE, YC (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 19 TC 22 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 267 EP 272 DI 10.1016/0257-8972(92)90250-E PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900047 ER PT J AU ALEXANDER, DE WAS, GS AF ALEXANDER, DE WAS, GS TI APPLICATION OF A THERMAL SPIKE MODEL TO EXPERIMENTAL ION-INDUCED GRAIN-GROWTH DATA SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID THIN-FILMS AB A model of ion-induced grain growth is developed incorporating the irradiation effect concept of thermal spikes. The results of the model predict that for normal grain growth the ion-induced mobility is linearly proportional to the quantity F(D)2/DELTA-H(coh)3, where F(D) is the ion and recoil energy deposited in nuclear interactions and DELTA-H(coh) is the cohesive energy. This linearity is shown to be supported by the data from six of seven previous ion-induced grain growth experiments. The model analysis is combined with the experimental data to determine values of the proportionality constant, beta(IIGG), relating the cohesive energy to the activation energy for grain growth (Q = -beta(IIGG)DELTA-H(coh)). The values are found to span a range, 0.05 less-than-or-equal-to beta(IIGG) less-than-or-equal-to 0.10, which is less than the value previously determined for the thermal spike treatment of ion beam mixing (beta(IM) = 0.14), and therefore consistent with the idea that atom migration across grain boundaries is easier than migration within the lattice. The consistency of results from the analysis of an entirely different phenomenon adds further credence to the thermal spike treatment of ion-induced grain growth. Finally, it is recommended that additional experiments be performed to evaluate further the model's validity. C1 UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109. RP ALEXANDER, DE (reprint author), ARGONNE NATL LAB,DIV MAT SCI,MSD 212,ARGONNE,IL 60439, USA. NR 16 TC 3 Z9 3 U1 2 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 333 EP 337 DI 10.1016/0257-8972(92)90260-H PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900057 ER PT J AU DEARNALEY, G ING, JL SUGDEN, S BROWN, IG GODECHOT, X AF DEARNALEY, G ING, JL SUGDEN, S BROWN, IG GODECHOT, X TI ANOMALOUS RANGES OF IONS IMPLANTED INTO CARBON SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV AB The range and distribution of ions in matter is or major importance in the modification of materials by implantation. In this investigation the metal vapor vacuum arc (MEVVA) ion source was used as a versatile means of generating beams of metallic ions to implant 26 different species into carbon targets to a dose of 10(16) ions cm-2. Vitreous carbon was chosen as the target in order to provide an electrically conducting low Z value material in which no channeling can occur and redistribution of implanted atoms by diffusion is very unlikely. Range distributions were determined by Rutherford backscattering spectroscopy. The charge state distribution for each ion species was monitored and used in conjunction with PRAL and TRIM code calculations to arrive at the theoretically predicted ion ranges. Mean ion energies were between 78 and 192 keV. The results show significant anomalies in range which are not inconsistent with an oscillatory Z1 dependence. For ion species in the region around Z1 = 75, the ratio of measured to calculated ranges can rise as high as 1.28 +/- 0.08, while around Z1 = 41 this ratio is significantly lower than 1.O. These findings are discussed in relation to other experimental observations and current theoretical ideas. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP DEARNALEY, G (reprint author), HARWELL LAB,DIDCOT OX11 0RA,OXON,ENGLAND. NR 15 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 364 EP 367 DI 10.1016/0257-8972(92)90265-C PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900062 ER PT J AU WILLIAMS, JM LEE, IS BUCHANAN, RA AF WILLIAMS, JM LEE, IS BUCHANAN, RA TI CHARGE INJECTION PROPERTIES OF IRIDIUM OXIDE-FILMS PRODUCED ON TI-6AL-4V ALLOY SUBSTRATES BY ION-BEAM MIXING TECHNIQUES SO SURFACE & COATINGS TECHNOLOGY LA English DT Article AB The charge injection capabilities of iridium oxide films, as produced on Ti-6Al-4V alloy substrates by ion-beam mixing techniques, were investigated. Iridium oxide is a valence change oxide. and therefore has high values of charge injection density upon voltage cycling in electrolytes. Because of this property, iridium oxide films are useful as working elements in neural prostheses. Iridium films of three thicknesses, produced by sputter deposition followed by ion beam mixing, were tested in cyclic voltammetry out to 1000 cycles or more. Two surface preparations, mechanical polishing and an acid passivation treatment, were also used as controls. Surface analysis was primarily by Rutherford backscattering spectrometry. Both the ion-beam mixing and the acid pretreatment increased the lifetimes of films, in comparison with the mechanically polished standards. Reductions in charge injection capability, when they occurred, were attributed to loss of iridium from the films, and there was a close correlation between the charge injection density and the iridium inventory. C1 UNIV TENNESSEE, DEPT MAT SCI & ENGN, KNOXVILLE, TN 37996 USA. RP OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. NR 13 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 385 EP 391 DI 10.1016/0257-8972(92)90269-G PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900066 ER PT J AU ROMANA, L THEVENARD, P RAMOS, S CANUT, B GEA, L BRUNEL, M HORTON, LL MCHARGUE, CJ AF ROMANA, L THEVENARD, P RAMOS, S CANUT, B GEA, L BRUNEL, M HORTON, LL MCHARGUE, CJ TI FORMATION OF SMALL METALLIC PRECIPITATES OF NIOBIUM IN ALPHA-AL2O3 IMPLANTED WITH NIOBIUM IONS SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV AB Niobium implantations were performed in alpha-Al2O3 single crystals to study the chemical interactions between the implanted species and the oxide and to study the microstructural evolution of the implanted layer. The investigation focused on both as-implanted specimens and specimens that underwent post-implantation anneals in a reducing atmosphere. Ion implantations were performed at 300 K with 150 keV particle energies and fluences ranging from 10(16) to 2 x 10(17) ions cm-2 . Rutherford backscattering spectroscopy (RBS) and X-ray photoemission spectroscopy (XPS) allowed the characterization of the implanted profiles and determination of the chemical state of the implanted ions. X-ray diffraction at glancing incidence and RBS analysis in a channeling geometry were performed to follow the microstructural evolution of the implanted layer. The oxidation state of niobium and the microstructure of the implanted layer were dependent on the atomic concentration of niobium in alpha-Al2O3. An amorphous phase was observed after a threshold fluence of 5 x 10(16) ions cm-2. The amorphous phase contained small metallic precipitates of niobium with a mean diameter of 1 nm. The physical properties of such niobium clusters embedded in an amorphous oxide layer were studied in detail. Electrical conductivity measurements showed that a hopping process between the metallic precipitates was the likely mechanism operating for this system. C1 CRISTALLOG LAB,CNRS,GRENOBLE,FRANCE. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV TENNESSEE,KNOXVILLE,TN 37996. RP ROMANA, L (reprint author), UNIV LYON 1,DEPT PHYS MAT,43 BLVD 11 NOVEMBRE 1918,F-69622 VILLEURBANNE,FRANCE. NR 18 TC 7 Z9 7 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 410 EP 414 DI 10.1016/0257-8972(92)90273-D PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900070 ER PT J AU ROMANA, LJ SKLAD, PS WHITE, CW MCCALLUM, JC CHOUDHURY, A HORTON, LL MCHARGUE, CJ AF ROMANA, LJ SKLAD, PS WHITE, CW MCCALLUM, JC CHOUDHURY, A HORTON, LL MCHARGUE, CJ TI FORMATION AND ANNEALING BEHAVIOR OF AN AMORPHOUS LAYER INDUCED BY TIN IMPLANTATION INTO SAPPHIRE SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID ION-IMPLANTATION AB The formation and annealing behavior of an amorphous layer produced by tin implantation into sapphire was studied. Tin ions with 180 keV energy were implanted into alpha-Al2O3 at 300 K with fluences ranging from 10(15) to 10(17) ions cm-2. The thermal stability of the damaged layer was investigated with post-implantation annealing treatments at temperatures up to 1375 K in either oxidizing or reducing atmospheres. The atomic spatial distribution of the ions was determined by Rutherford backscattering spectroscopy in random and channeling geometries. The structure of the implanted layer was determined by analytical electron microscopy. The degree of disorder was found to increase linearly with fluence up to the threshold for amorphization, approximately 1 x 10(16) ions cm-2. The microstructure of the implanted layer after the thermal treatments depended on the annealing atmosphere. The well known amorphous --> gamma-Al2O3 --> alpha-Al2O3 phase transition was observed during annealing in a reducing atmosphere. However, anneals in an oxidizing environment led to the formation of the compound SnO2, which was found to stabilize the cubic gamma-Al2O3 phase. RP ROMANA, LJ (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 16 TC 2 Z9 2 U1 0 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 415 EP 419 DI 10.1016/0257-8972(92)90274-E PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900071 ER PT J AU JAMES, MR LAM, NQ REHN, LE BALDO, PM FUNK, L STUBBINS, JF AF JAMES, MR LAM, NQ REHN, LE BALDO, PM FUNK, L STUBBINS, JF TI HIGH-TEMPERATURE IMPLANTATION OF GOLD INTO NICKEL SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID SEGREGATION; REDISTRIBUTION; BOMBARDMENT; SURFACE; IONS AB The role of irradiation temperature on implant distributions was investigated in the Au-Ni system. Gold ions were implanted at 300 keV into polycrystalline nickel samples at temperatures between 25 and 700-degrees-C to a dose of 10(16) cm-2. The spatial gold distributions were analyzed with Rutherford backscattering spectrometry, using both 1.7 and 3.0 MeV He-4, and secondary ion mass spectrometry. The results showed that the gold profiles were practically insensitive to target temperature below about 200-degrees-C. At higher temperatures, systematic decreases in the surface and peak concentrations and longer penetration tails were observed. The evolution of the implant distribution in time and space during implantation was also calculated theoretically by means of a comprehensive kinetic model. In general, the effects observed experimentally can be reproduced theoretically, and interpreted in terms of substantial sputtering at low temperatures, and dominant radiation-induced segregation at higher temperatures. In addition, a systematic fitting of model calculations to experimental measurements allowed the determination of various defect parameters. C1 UNIV ILLINOIS,DEPT NUCL ENGN,URBANA,IL 61801. RP JAMES, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 20 TC 0 Z9 0 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 435 EP 440 DI 10.1016/0257-8972(92)90277-H PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900074 ER PT J AU RANKIN, J THEVENARD, P ROMANA, LJ BOATNER, LA WHITE, CW MCHARGUE, CJ HORTON, LL AF RANKIN, J THEVENARD, P ROMANA, LJ BOATNER, LA WHITE, CW MCHARGUE, CJ HORTON, LL TI ION-BOMBARDMENT, ULTRASONIC, AND PULSED LASER-BEAM EFFECTS ON SMALL METALLIC CLUSTERS OF POTASSIUM IN MGO SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV AB Small metallic precipitates of potassium were produced in ion-implanted layers (5 x 10(16) K+ ions cm-2, 150 keV, 300 K) on {100} faces of single crystals of MgO by thermal annealing in air at 1000 K. The resulting potassium aggregates had a mean size of 7 nm as characterized by optical absorption measurements and analytical electron microscopy. The effects of three distinct treatments on these precipitates and the implanted layer as a whole were investigated. Ion bombardment with Ar2+(1 x 10(16) ions cm-2, 300 keV, 300 K) results in a dissolution of the metallic clusters and the production of F+ and V- centers, as evidenced by the relative changes in the corresponding absorption bands. Rutherford backscattering spectroscopy indicates that this dissolution of precipitates does not result in any long-range redistribution of the potassium. Laser irradiation at a frequency near the absorption resonance of the potassium metal (1-mu-m wavelength) produces an exfoliation of the implanted layer. A similar effect occurs in ultrasonically treated samples where the entire implanted layer is removed after a 12 min exposure to an energy flux of 120 W cm-2. The similarities and differences among these treatments are discussed along with suggestions for further study. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP RANKIN, J (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 12 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 471 EP 475 DI 10.1016/0257-8972(92)90284-H PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900081 ER PT J AU BROWN, IG DICKINSON, MR GALVIN, JE GODECHOT, X MACGILL, RA AF BROWN, IG DICKINSON, MR GALVIN, JE GODECHOT, X MACGILL, RA TI VERSATILE HIGH-CURRENT METAL-ION IMPLANTATION FACILITY SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON SURFACE MODIFICATION OF METALS BY ION BEAMS ( SMMIB-91 ) CY JUL 14-19, 1991 CL GEORGETOWN UNIV, WASHINGTON, DC SP USN, OFF NAVAL RES, USA, RES OFF, ANATECH, COMMONWEALTH SCI, IMPLANT SCI, NISSIN ELECT, PEABODY SCI, SPIRE, ULTRA HIGH VACUUM INSTRUMENTS HO GEORGETOWN UNIV ID VAPOR VACUUM-ARC; PLASMA AB A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. RP BROWN, IG (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 28 TC 23 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD APR 15 PY 1992 VL 51 IS 1-3 BP 529 EP 533 DI 10.1016/0257-8972(92)90293-J PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HV289 UT WOS:A1992HV28900090 ER PT J AU KELLOGG, GL AF KELLOGG, GL TI SURFACE-DIFFUSION OF PT ADATOMS ON NI SURFACES SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID ATOMIC EXCHANGE MECHANISM; SELF-DIFFUSION AB The diffusion of individual Pt adatoms on the (100), (110), (311), and (111) surfaces of Ni has been investigated by field ion microscopy. On the (100) and (110) surfaces Pt adatoms replace Ni substrate atoms at temperatures below the onset of hopping displacements. The minimum temperature required for replacement is 250 and 105 K for the (100) and (110) surfaces, respectively. On the (311) and (111) surfaces, Pt adatoms migrate by conventional site-to-site hopping. The activation barriers for displacements on the (100), (110), and (311) planes are estimated from the migration temperatures and compared to activation barriers measured previously for self-diffusion on Pt and Ni. RP KELLOGG, GL (reprint author), SANDIA NATL LABS,DIV 1114,ALBUQUERQUE,NM 87185, USA. NR 17 TC 35 Z9 35 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 18 EP 23 DI 10.1016/0039-6028(92)90991-E PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800005 ER PT J AU MILLER, MK RUSSELL, KF AF MILLER, MK RUSSELL, KF TI FRACTAL ANALYSIS OF FIELD EVAPORATION MICROGRAPHS OF FE-CR ALLOYS SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID MICROSTRUCTURES AB Fractal analysis has been performed on the interphase interface between the chromium-enriched alpha' phase and the iron-rich alpha phase from digitized two-dimensional sections of the microstructure obtained by field evaporation microscopy. The field evaporation micrographs revealed that the interphase interface was rough on the atomic scale. The fractal dimension of the interface was found to be between 1.1 and 1.5 indicating that the interface is fractal in nature. RP MILLER, MK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,MS 6376,OAK RIDGE,TN 37831, USA. NR 9 TC 11 Z9 11 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 232 EP 236 DI 10.1016/0039-6028(92)91025-7 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800039 ER PT J AU JAYARAM, R MILLER, MK AF JAYARAM, R MILLER, MK TI AN APFIM ANALYSIS OF GRAIN-BOUNDARIES AND PRECIPITATION IN BORON-DOPED NIAL SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID ATOM PROBE; NI3AL AB An atom probe characterization of a stoichiometric NiAl alloy doped with 100 wt. ppm of boron has been performed. Field ion micrographs revealed boron segregation to the grain boundaries. Atom probe analysis of the grain boundaries measured a boron coverage of up to 30% of a monolayer. A low number density of (Ti, V, Cr)B2 precipitates with a size distribution ranging from 10 to < 1 nm radius was also observed in the matrix. Atom probe analysis of the matrix revealed that approximately 2/3 of the boron remained in solid solution. The increase in the yield stress observed over the undoped alloy is due to a combination of boron solid solution strengthening and precipitation hardening from the boride precipitates. RP JAYARAM, R (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 15 TC 22 Z9 22 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 310 EP 315 DI 10.1016/0039-6028(92)91038-D PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800052 ER PT J AU JAYARAM, R MILLER, MK AF JAYARAM, R MILLER, MK TI AN APFIM TEM STUDY OF CREPT MODEL NI-MO-TA-AL SUPERALLOYS SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID NICKEL-BASE SUPERALLOYS; CREEP-PROPERTIES; ATOM PROBE AB The influence of initial microstructure and Mo composition on the high-temperature creep behaviour of two crept model Ni-x at.%Mo-2.0 at.%Ta-13.7 at.%Al(x = 8.7 and 9.2 at.%) superalloys has been investigated by the techniques of transmission electron microscopy (TEM) and atom probe field ion microscopy (APFIM). Acicular delta-phase precipitates of approximate stoichiometry NiMo have been observed by TEM and APFIM in both alloys. However, a marked difference in gamma' morphology is observed between the alloys due to different initial microstructures. Small variations in the initial morphologies of the gamma' microstructure rather than Mo composition play a significant role in affecting creep strength in this alloy system. RP JAYARAM, R (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 12 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 316 EP 321 DI 10.1016/0039-6028(92)91039-E PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800053 ER PT J AU HYDE, JM CEREZO, A HETHERINGTON, MG MILLER, MK SMITH, GDW AF HYDE, JM CEREZO, A HETHERINGTON, MG MILLER, MK SMITH, GDW TI 3-DIMENSIONAL CHARACTERIZATION AND MODELING OF SPINODALLY DECOMPOSED IRON-CHROMIUM ALLOYS SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK AB The iron-chromium system has a spinodal region within which a random solid solution is thermodynamically unstable with respect to small composition fluctuations. The resulting decomposition yields Cr-enriched alpha' and Fe-rich alpha phases forming complex and often interconnected morphologies. The resultant physical properties of the alloy are dependent on the scale and morphology of the microstructure and the amplitude of composition fluctuations. In this paper, the results of a series of thermally aged Fe-Cr specimens that have been analyzed with the position sensitive atom probe (POSAP) are compared with the results from a Monte Carlo simulation of the decomposition process. The resulting microstructures have been analyzed in terms of scale, composition amplitude and morphology. The scale has been measured by an autocorrelation analysis and the composition amplitude calculated from an analysis of the frequency distribution of block compositions. New morphological analysis techniques based on the measurement of a fractal dimension, and counting the number of handles within the microstructure, have been applied to characterize the detailed morphology on a subnanometre scale. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP HYDE, JM (reprint author), UNIV OXFORD,DEPT MAT,PARKS RD,OXFORD OX1 3PH,ENGLAND. NR 15 TC 20 Z9 20 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 370 EP 377 DI 10.1016/0039-6028(92)91048-G PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800062 ER PT J AU ZHANG, J MILLER, MK WILLIAMS, DB GOLDSTEIN, JI AF ZHANG, J MILLER, MK WILLIAMS, DB GOLDSTEIN, JI TI AN APFIM AEM STUDY OF PHASE DECOMPOSITIONS IN FE-NI ALLOYS AT LOW-TEMPERATURES SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID IRON-METEORITES; ORDERED FENI; TRANSFORMATIONS; PROBE AB A combined atom probe field ion microscopy and analytical electron microscopy characterization has been performed on laboratory aged martensitic and austenitic specimens of FeNi and FeNiP alloys. These techniques revealed that the martensitic 24.1 and 28.6at.%Ni alloys decomposed during aging for 1 year at 300-degrees-C to form face centered cubic precipitates of approximately 56at.%Ni in a body centered cubic matrix containing approximately 20at.%Ni. Some thin platelets were observed in the field ion micrographs of the austenitic Fe-42.9at.%Ni alloy and the Fe-43.2at.%Ni-0.44at.%P alloy after aging at 400 and 350-degrees-C. Atom probe analysis revealed phosphorus clustering in the ternary alloy aged at 300-degrees-C. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP ZHANG, J (reprint author), LEHIGH UNIV,DEPT MAT SCI & ENGN,BETHLEHEM,PA 18015, USA. NR 24 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 433 EP 440 DI 10.1016/0039-6028(92)91057-I PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800071 ER PT J AU MILLER, MK RUSSELL, KF AF MILLER, MK RUSSELL, KF TI AN APFIM INVESTIGATION OF A WEATHERED REGION OF THE SANTA CATHARINA METEORITE SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID ALLOYS AB An atom probe field ion microscope characterization has been performed on a weathered region of the Santa Catharina meteorite (USNM #3043). This meteorite consists primarily of a metallic matrix, oxides, and Schreibersite (FeNi)3P. The metallic matrix was found to have decomposed into a random distribution of approximately 12 nm diameter precipitates with compositions ranging from 38.6-54 at.% Ni in a matrix with lower nickel levels. Atom probe composition profiles between precipitates revealed a characteristic W-shaped nickel profile ranging from approximately 15% nickel adjacent to the precipitates to approximately 25% nickel in the central region away from the precipitates. RP MILLER, MK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 441 EP 445 DI 10.1016/0039-6028(92)91058-J PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800072 ER PT J AU MILLER, MK CEREZO, A HETHERINGTON, MG HYDE, JM AF MILLER, MK CEREZO, A HETHERINGTON, MG HYDE, JM TI ESTIMATION OF COMPOSITION AMPLITUDE - PA AND LBM VERSUS V SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK AB A comparison is made of the methods that are used for estimating the composition amplitudes of the co-existing phases present in a two phase material from composition profiles obtained by random area analyses in the atom probe field ion microscope. The parameters evaluated are the 2P(a) parameter from the P(a) method, the mu(2) - mu(1) parameter from the LBM model, and the V and peak difference parameters from the Variation method. A comparison is also made of the methods by fitting the parameters generated by the Variation method to theoretical distributions assumed by the P(a) and LBM methods. C1 UNIV OXFORD,DEPT MAT,OXFORD OX1 3PH,ENGLAND. RP MILLER, MK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 6 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 446 EP 452 DI 10.1016/0039-6028(92)91059-K PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800073 ER PT J AU MILLER, MK JAYARAM, R AF MILLER, MK JAYARAM, R TI SOME FACTORS AFFECTING ANALYSIS IN THE ATOM PROBE SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID FIELD EVAPORATION AB Preferential evaporation and retention of elements during pulsed field evaporation of a specimen is known to affect the results of a chemical analysis in the atom probe field ion microscope. Field evaporation produced by increasing the standing voltage on the specimen alters the surface chemistry because the more easily field evaporated elements will be removed preferentially. This change in surface chemistry will result in incorrect compositions being measured for small precipitates, boundaries or surfaces. The use of pulsed field evaporation should be adopted in these cases to avoid this problem. The shape of the specimen was found to change between DC and pulsed field evaporated conditions. RP MILLER, MK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 6 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 458 EP 462 DI 10.1016/0039-6028(92)91061-F PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800075 ER PT J AU CEREZO, A HETHERINGTON, MG HYDE, JM MILLER, MK SMITH, GDW UNDERKOFFLER, JS AF CEREZO, A HETHERINGTON, MG HYDE, JM MILLER, MK SMITH, GDW UNDERKOFFLER, JS TI VISUALIZATION OF 3-DIMENSIONAL MICROSTRUCTURES SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID ATOM PROBE AB A variety of techniques are now available which can yield three-dimensional data on the atomic scale microstructures of materials. These include sequences of field-ion micrographs, field evaporation microscopy and direct chemical measurements from three-dimensional atom probes such as the position-sensitive atom probe. Methods of computer reconstruction of the microstructures from the various forms of data are discussed, together with the problems associated with the different data types. Despite the different methods for the collection of microstructural data, a common format is produced which allows topological measurements to be performed. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. MIT,MEDIA LAB,CAMBRIDGE,MA 02139. RP CEREZO, A (reprint author), UNIV OXFORD,DEPT MAT,PARKS RD,OXFORD OX1 3PH,ENGLAND. NR 9 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 471 EP 480 DI 10.1016/0039-6028(92)91063-H PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800077 ER PT J AU CEREZO, A HYDE, JM MILLER, MK BEVERINI, G SETNA, RP WARREN, PJ SMITH, GDW AF CEREZO, A HYDE, JM MILLER, MK BEVERINI, G SETNA, RP WARREN, PJ SMITH, GDW TI NEW DIMENSIONS IN ATOM-PROBE ANALYSIS SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK ID FIELD-ION MICROSCOPY; DECOMPOSITION; DETECTORS; PHOTON; ANODES AB A new class of atom-probe instruments has recently been developed which combine single atom sensitivity mass spectrometry with position sensing, and have the potential of reconstructing nanometre-scale composition variations in three-dimensions. These techniques will be very powerful in the study of the early stages of phase transformations, and surface and interface segregation. Some recent results obtained with the first of these instruments, the position-sensitive atom probe, are described. Difficulties arise in this instrument when more than one ion is evaporated from the analysis area on a single field evaporation pulse, which can limit the accuracy of analysis performed on the resultant data. Other three-dimensional atom-probe instruments currently under development are described, and their expected performance in this respect is discussed. The significance of defining composition on the sub-nanometre scale is addressed, and the importance of atomic-scale modelling of the phenomena under investigation is indicated. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP CEREZO, A (reprint author), UNIV OXFORD,DEPT MAT,PARKS RD,OXFORD OX1 3PH,ENGLAND. NR 29 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 481 EP 493 DI 10.1016/0039-6028(92)91064-I PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800078 ER PT J AU MILLER, MK AF MILLER, MK TI IMPLEMENTATION OF THE OPTICAL ATOM PROBE SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 38TH INTERNATIONAL FIELD EMISSION SYMP : FIELD EMISSION 91 CY AUG 05-09, 1991 CL VIENNA, AUSTRIA SP BUNDESMINIST WISSENSCH & FORSCH, OSTERREICH FORSCHUNGSGEMEINSCH, WIENER FREMDENVERKEHRSVERBAND, ERSTE OSTERREICH SPAR CASSE BANK AB A serial version of a three-dimensional atom probe has been constructed. The main components of the optical atom probe (OAP) are a Galileo Electro-optics FIM70 detector, a fiberoptics reducing taper, an ITT4111 image intensifier tube, an EG & G reticon MC9256 CCD camera, a Data Design Corporation AC100 CAMAC module and a LeCroy 4208 time-to-digital converter. The instrument may be used in several modes such as a field-ion microscope, a computerized field evaporation microscope, a wide angle atom probe, and a three-dimensional atom probe. RP MILLER, MK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 8 TC 30 Z9 31 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 15 PY 1992 VL 266 IS 1-3 BP 494 EP 500 DI 10.1016/0039-6028(92)91065-J PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA HM788 UT WOS:A1992HM78800079 ER PT J AU BOESTEN, L TANAKA, H KOBAYASHI, A DILLON, MA KIMURA, M AF BOESTEN, L TANAKA, H KOBAYASHI, A DILLON, MA KIMURA, M TI CROSSED-BEAM EXPERIMENT FOR THE SCATTERING OF LOW-ENERGY ELECTRONS FROM CF4 SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID VIBRATIONAL-EXCITATION; POLYATOMIC-MOLECULES; SELECTION-RULES; IMPACT; SECTIONS; ATTACHMENT; COLLISIONS; RANGE; CH4; PERFLUOROALKANES AB Differential scattering cross sections (DCS) for electron-CF4 collisions in the energy range from 1.5 to 100 eV were measured with a crossed beam instrument for scattering angles of 15-degrees to 130-degrees. The DCS are normalized by reference to He. Integral and momentum transfer cross sections are compared with measurements of total cross sections, swarm experiments and theory. The integrated DCS show a broad structure at 7 eV of symmetry T2 as predicted by theory, and one broad peak from 15 to 25 eV. The observed peaks differ in magnitude and angular distribution from recent SMC calculations. Evidence of a shape resonance of T2 symmetry was observed in the recorded angular distributions for vibrational modes nu(0), nu(1), nu(3), and nu(4). In addition a large cross section for nu(3) excitation with 2 eV electrons was found to occur by a direct mechanism. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP BOESTEN, L (reprint author), SOPHIA UNIV,DEPT GEN SCI & PHYS,TOKYO 102,JAPAN. NR 51 TC 73 Z9 73 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD APR 14 PY 1992 VL 25 IS 7 BP 1607 EP 1620 DI 10.1088/0953-4075/25/7/029 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HQ156 UT WOS:A1992HQ15600030 ER PT J AU KREMSER, C HEISS, W UNTERRAINER, K GORNIK, E HALLER, EE HANSEN, WL AF KREMSER, C HEISS, W UNTERRAINER, K GORNIK, E HALLER, EE HANSEN, WL TI STIMULATED-EMISSION FROM P-GE DUE TO TRANSITIONS BETWEEN LIGHT-HOLE LANDAU-LEVELS AND EXCITED-STATES OF SHALLOW IMPURITIES SO APPLIED PHYSICS LETTERS LA English DT Article ID MAGNETIC-FIELDS; LASER; GERMANIUM AB We investigate the far infrared emission spectra obtained from the so-called p-Ge light-heavy-hole laser. The occurrence of a frequency gap between the observed low-frequency and high-frequency range is for the first time explained by self-absorption due to impurity transitions. In the high-frequency range we find evidence of transitions between light-hole Landau levels and excited states of shallow impurities to be responsible for the lasing transitions. C1 TECH UNIV MUNICH,WALTER SCHOTTKY INST,W-8046 GARCHING,GERMANY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP KREMSER, C (reprint author), UNIV INNSBRUCK,INST EXPTL PHYS,A-6020 INNSBRUCK,AUSTRIA. RI Kremser, Christian/A-5031-2008; Heiss, Wolfgang/F-1200-2011; Unterrainer, Karl/J-4248-2016 OI Heiss, Wolfgang/0000-0003-0430-9550; Unterrainer, Karl/0000-0003-1970-9071 NR 14 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 13 PY 1992 VL 60 IS 15 BP 1785 EP 1787 DI 10.1063/1.107164 PG 3 WC Physics, Applied SC Physics GA HN481 UT WOS:A1992HN48100005 ER PT J AU SCHNEIDER, RP BRYAN, RP LOTT, JA OLBRIGHT, GR AF SCHNEIDER, RP BRYAN, RP LOTT, JA OLBRIGHT, GR TI VISIBLE (657 NM) INGAP/INALGAP STRAINED QUANTUM-WELL VERTICAL-CAVITY SURFACE-EMITTING LASER SO APPLIED PHYSICS LETTERS LA English DT Article AB We report the first visible (657 nm) vertical-cavity surface-emitting laser. The photopumped undoped structure was grown using low-pressure metalorganic vapor-phase epitaxy in a single-growth sequence on misoriented GaAs substrates. The optical cavity consists of an In0.54Ga0.46P/In0.48(Al0.7Ga0.3)0.52 P strained quantum-well active region and a lattice-matched In0.48(AlyGa1-y)0.52 P (0.7 less-than-or-equal-to y less-than-or-equal-to 1.0) graded spacer region, while the distributed Bragg reflectors are composed of Al0.5Ga0.5As/AlAs quarter-wave stacks. Room-temperature optically pumped lasing was achieved with a very low-threshold power, clearly demonstrating the viability of this new technology. These results provide the foundation for visible semiconductor laser-diode arrays for a number of applications including laser projection displays, holographic memories, and plastic fiber communication. C1 PHOTON RES INC,BROOMFIELD,CO 80021. RP SCHNEIDER, RP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 22 TC 26 Z9 26 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 13 PY 1992 VL 60 IS 15 BP 1830 EP 1832 DI 10.1063/1.107178 PG 3 WC Physics, Applied SC Physics GA HN481 UT WOS:A1992HN48100020 ER PT J AU MIKLICH, AH CLARKE, J COLCLOUGH, MS CHAR, K AF MIKLICH, AH CLARKE, J COLCLOUGH, MS CHAR, K TI FLICKER (1/F) NOISE IN BIEPITAXIAL GRAIN-BOUNDARY JUNCTIONS OF YBA2CU3O7-X SO APPLIED PHYSICS LETTERS LA English DT Article ID DC SQUIDS AB At low frequencies f the 1/f noise power in single biepitaxial junctions of YBa2Cu3 O7-x peaks sharply for bias currents just above the noise reduced critical current and increases as I2 for high bias currents I. This behavior is explained by a model in which both critical current fluctuations delta-I0 and resistance fluctuations delta-R contribute to the measured voltage noise. The magnitude of the normalized critical-current fluctuations \delta-I0/I0\ is alway much greater than that of the normalized resistance fluctuations \delta-R/R\. Switching the bias current between positive and negative values at 2 kHz greatly reduces the magnitude of the 1/f noise from both sources, implying that the coherence of the noise generating process is not affected by the current reversal. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. CONDUCTUS INC,SUNNYVALE,CA 94086. RP MIKLICH, AH (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 18 TC 71 Z9 71 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 13 PY 1992 VL 60 IS 15 BP 1899 EP 1901 DI 10.1063/1.107147 PG 3 WC Physics, Applied SC Physics GA HN481 UT WOS:A1992HN48100043 ER PT J AU LIBURDY, RP AF LIBURDY, RP TI CALCIUM SIGNALING IN LYMPHOCYTES AND ELF FIELDS - EVIDENCE FOR AN ELECTRIC-FIELD METRIC AND A SITE OF INTERACTION INVOLVING THE CALCIUM-ION CHANNEL SO FEBS LETTERS LA English DT Article DE INTRACELLULAR CALCIUM; CALCIUM TRANSPORT; SIGNAL TRANSDUCTION; LYMPHOCYTE; EXTREMELY-LOW-FREQUENCY (ELF) ELECTRIC AND MAGNETIC FIELD ID ELECTROMAGNETIC-FIELDS; ACTIVATION; CELLS; EXPOSURE; RECEPTOR; HZ AB Calcium influx increased during mitogen-activated signal transduction in thymic lymphocytes exposed to a 22 mT, 60 Hz magnetic field (E(induced) = 1.7 mV/cm, 37-degrees-C, 60 min). To distinguish between an electric or a magnetic field dependence a special multi-ring annular cell culture plate based on Faraday's Law of Induction was employed. Studies show a dependence on the strength of the induced electric field at constant magnetic flux density. Moreover, exposure to a pure 60 Hz electric field or to a magnetically-induced electric field of identical strength resulted in similar changes in calcium transport. The first real-time monitoring of [Ca2+]i during application of a 60 Hz electric field revealed an increase in [Ca2+]i observed 100 s after mitogen stimulation; this suggests that the plateau phase rather than the early phase of calcium signaling was influenced. The hypothesis was tested by separating, in time, the early release of calcium from intracellular stores from the influx of extracellular calcium. In calcium-free buffer, 60 Hz fields exerted little influence on the early release of calcium from intracellular stores. In contrast, addition of extracellular calcium during exposure enhanced calcium influx through the plasma membrane. Alteration of the plateau phase of calcium signaling implicates the calcium channel as a site of field interaction. In addition, an electric field exposure metric is mechanistically consistent with a cell-surface interaction site. RP LIBURDY, RP (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV RES MED & RADIAT BIOPHYS,BERKELEY,CA 94720, USA. FU NCI NIH HHS [CA53711] NR 35 TC 165 Z9 171 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD APR 13 PY 1992 VL 301 IS 1 BP 53 EP 59 DI 10.1016/0014-5793(92)80209-Y PG 7 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA HQ681 UT WOS:A1992HQ68100013 PM 1333413 ER PT J AU CHAPELLE, F BURGIO, GF CHOMAZ, P RANDRUP, J AF CHAPELLE, F BURGIO, GF CHOMAZ, P RANDRUP, J TI FLUCTUATIONS IN NUCLEAR-DYNAMICS - COMPARISON OF DIFFERENT METHODS SO NUCLEAR PHYSICS A LA English DT Article ID COLLISIONS AB We compare several methods for incorporating the effect of the fluctuating collision integral in Boltzmann-Uehling-Uhlenbeck simulations of nuclear dynamics: the method of correlated pseudo-particle collisions proposed by Bauer, Bertsch and Das Gupta, the method of projection onto collective variables (specifically the local quadrupole moment of the momentum distribution) proposed by Ayik and Gregoire, and the method of direct simulation on a lattice in phase space recently proposed by Burgio, Chomaz and Randrup. Considering a periodic two-dimensional nucleon gas in a constant one-body field, we examine the evolution of the fluctuations of the phase-space occupancy and their correlations. RP CHAPELLE, F (reprint author), LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 10 TC 23 Z9 23 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 APR 13 PY 1992 VL 540 IS 1-2 BP 227 EP 260 DI 10.1016/0375-9474(92)90202-U PG 34 WC Physics, Nuclear SC Physics GA HV790 UT WOS:A1992HV79000012 ER PT J AU ALVAREZ, O SINGER, IM WINDEY, P AF ALVAREZ, O SINGER, IM WINDEY, P TI THE SUPERSYMMETRIC SIGMA-MODEL AND THE GEOMETRY OF THE WEYL-KAC CHARACTER FORMULA SO NUCLEAR PHYSICS B LA English DT Article ID ATIYAH-SINGER INDEX; ELLIPTIC GENERA; STRING THEORY; 2 DIMENSIONS; FIELD-THEORY; BOSONIZATION AB Field theoretic and geometric ideas are used to construct a chiral supersymmetric field theory for which the ground state is a specified irreducible representation of a centrally extended loop group. The character index of the associated supercharge (an appropriate Dirac operator on LG/T) is the Weyl-Kac character formula which we compute explicitly by the steepest-descent approximation. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. MIT,DEPT MATH,CAMBRIDGE,MA 02139. UNIV PARIS 06,CNRS,PHYS THEOR & HAUTES ENERGIES LAB,F-75252 PARIS 05,FRANCE. RP ALVAREZ, O (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 32 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 13 PY 1992 VL 373 IS 3 BP 647 EP 687 DI 10.1016/0550-3213(92)90270-L PG 41 WC Physics, Particles & Fields SC Physics GA HQ189 UT WOS:A1992HQ18900004 ER PT J AU DAWSON, S KAUFFMAN, RP AF DAWSON, S KAUFFMAN, RP TI PRODUCTION-RATES FOR HIGGS BOSON PLUS MULTIPLE JETS AT THE SUPERCONDUCTING SUPER COLLIDER SO PHYSICAL REVIEW LETTERS LA English DT Article ID GAUGE-THEORIES; HIGH-ENERGIES; BREMSSTRAHLUNG; MASS; AMPLITUDES; QUARK AB We consider the gluon fusion process gg --> ggH in the limit that the top quark is much heavier than the Higgs boson. At high energy hadron colliders such as the CERN Large Hadron Collider and the Superconducting Super Collider, this process is an important source of Higgs bosons at large transverse momentum. C1 UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. RP DAWSON, S (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 21 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 13 PY 1992 VL 68 IS 15 BP 2273 EP 2276 DI 10.1103/PhysRevLett.68.2273 PG 4 WC Physics, Multidisciplinary SC Physics GA HP054 UT WOS:A1992HP05400005 ER PT J AU MCDONALD, JW SCHNEIDER, D CLARK, MW DEWITT, D AF MCDONALD, JW SCHNEIDER, D CLARK, MW DEWITT, D TI OBSERVATION OF HIGH ELECTRON-EMISSION YIELDS FOLLOWING HIGHLY CHARGED ION IMPACT (UP TO TH(75+)) ON SURFACES SO PHYSICAL REVIEW LETTERS LA English DT Article ID TUNGSTEN SURFACE; METAL-SURFACE; SLOW; TRAP AB Doubly differential electron emission yields following the impact of fast (3.95 x 10(7) cm/sec) Ar9,12,18+, Ne9+, Xe30,44+, and Th70.75+ ions on Cu and Au targets have been measured. The electron emission is dominated by low-energy electrons (< 50 eV). It is found that the total yield, which rises to about 100 electrons per ion, is a nonlinear function of the total potential energy of the incident ion (up to about 200 keV). C1 UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. RP MCDONALD, JW (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 25 TC 44 Z9 45 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 13 PY 1992 VL 68 IS 15 BP 2297 EP 2300 DI 10.1103/PhysRevLett.68.2297 PG 4 WC Physics, Multidisciplinary SC Physics GA HP054 UT WOS:A1992HP05400011 ER PT J AU BORISOV, AB BOROVSKIY, AV KOROBKIN, VV PROKHOROV, AM SHIRYAEV, OB SHI, XM LUK, TS MCPHERSON, A SOLEM, JC BOYER, K RHODES, CK AF BORISOV, AB BOROVSKIY, AV KOROBKIN, VV PROKHOROV, AM SHIRYAEV, OB SHI, XM LUK, TS MCPHERSON, A SOLEM, JC BOYER, K RHODES, CK TI OBSERVATION OF RELATIVISTIC AND CHARGE-DISPLACEMENT SELF-CHANNELING OF INTENSE SUBPICOSECOND ULTRAVIOLET (248 NM) RADIATION IN PLASMAS SO PHYSICAL REVIEW LETTERS LA English DT Article ID TUNNELING IONIZATION; LASER-PULSES; FIELD AB Experimental studies examining a new relativistic regime of high-intensity short-pulse propagation in plasmas have been performed which present evidence for the formation of a stable mode of spatially confined (channeled) propagation. For an electron density of approximately 1.35 x 10(21) cm-3 and a power of approximately 3 x 10(11) W, the results indicate a channel radius < 1-mu-m and a peak intensity approximately 10(19) W/cm2. Comparison of these findings with a dynamical theory yields agreement for both the longitudinal structure and the radial extent of the propagation observed. C1 ACAD SCI USSR,INST GEN PHYS,MOSCOW 117942,USSR. UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60680. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP BORISOV, AB (reprint author), MV LOMONOSOV STATE UNIV,CTR RES COMP,COMP SIMULAT LAB,MOSCOW 119899,USSR. NR 17 TC 274 Z9 274 U1 2 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 APR 13 PY 1992 VL 68 IS 15 BP 2309 EP 2312 DI 10.1103/PhysRevLett.68.2309 PG 4 WC Physics, Multidisciplinary SC Physics GA HP054 UT WOS:A1992HP05400014 ER PT J AU NELSON, DR VINOKUR, VM AF NELSON, DR VINOKUR, VM TI BOSON LOCALIZATION AND PINNING BY CORRELATED DISORDER IN HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTORS; VORTEX-GLASS SUPERCONDUCTIVITY; BA-CU-O; FLUX LIQUIDS; CRYSTAL; CREEP AB The physics of flux lines in the cuprate superconductors pinned by columnar defects is mapped onto boson localization in two dimensions. The theory predicts a Bose glass phase with an infinite tilt modulus and zero linear resistivity, as well as an entangled flux liquid. We describe correlations and transport in these phases, and propose a scaling theory for the irreversibility line which separates them. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. ACAD SCI USSR,INST SOLID STATE PHYS,MOSCOW V-71,USSR. RP NELSON, DR (reprint author), HARVARD UNIV,LYMAN LAB PHYS,CAMBRIDGE,MA 02138, USA. NR 25 TC 532 Z9 532 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 APR 13 PY 1992 VL 68 IS 15 BP 2398 EP 2401 DI 10.1103/PhysRevLett.68.2398 PG 4 WC Physics, Multidisciplinary SC Physics GA HP054 UT WOS:A1992HP05400037 ER PT J AU ERCK, R AF ERCK, R TI LONG-LIVED MICE SO NEW SCIENTIST LA English DT Letter RP ERCK, R (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, 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 SN 0262-4079 J9 NEW SCI JI New Sci. PD APR 11 PY 1992 VL 134 IS 1816 BP 49 EP 49 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HP336 UT WOS:A1992HP33600057 ER PT J AU TYNAN, K OLSEN, A TRASK, B DEJONG, P THOMPSON, J ZIMMERMANN, W CARRANO, A MOHRENWEISER, H AF TYNAN, K OLSEN, A TRASK, B DEJONG, P THOMPSON, J ZIMMERMANN, W CARRANO, A MOHRENWEISER, H TI ASSEMBLY AND ANALYSIS OF COSMID CONTIGS IN THE CEA-GENE FAMILY REGION OF HUMAN CHROMOSOME-19 SO NUCLEIC ACIDS RESEARCH LA English DT Article ID HUMAN CARCINOEMBRYONIC ANTIGEN; CDNA CLONES; EXPRESSION; LOCALIZATION; EVOLUTION; LIBRARIES; MEMBERS; CLONING; REVEAL AB The carcinoembryonic antigen (CEA)-like genes are members of a large gene family which is part of the immunoglobulin superfamily. The CEA family is divided into two major subgroups, the CEA-subgroup and the pregnancy-specific glycoprotein (PSG)-subgroup. In the course of an effort to develop a set of overlapping cosmids spanning human chromosome 19, we identified 245 cosmids in a human chromosome 19 cosmid library (6 - 7X redundant) by hybridization with an IgC-like domain fragment of the CEA gene. A fluorescence-based restriction enzyme digest fingerprinting strategy was used to assemble 212 probe-positive cosmids, along with 115 additional cosmids from a collection of approximately 8,000 randomly selected cosmids, into five contigs. Two of the contigs contain CEA-subgroup genes while the remaining three contigs contain PSG-subgroup genes. These five contigs range in size from 100 kb to over 300 kb and span an estimated 1 Mb. The CEA-like gene family was determined by fluorescence in situ hybridization to map in the q13.1-q13.2 region of human chromosome 19. Analysis of the two CEA-subgroup contigs provided verification of the contig assembly strategy and insight into the organization of 9 CEA-subgroup genes. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,DIV BIOMED SCI,LIVERMORE,CA 94550. UNIV FREIBURG,INST IMMUNOBIOL,W-7800 FREIBURG,GERMANY. RI Zimmermann, Wolfgang/L-9277-2013 NR 36 TC 40 Z9 40 U1 0 U2 1 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 11 PY 1992 VL 20 IS 7 BP 1629 EP 1636 DI 10.1093/nar/20.7.1629 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA HQ054 UT WOS:A1992HQ05400028 PM 1579453 ER PT J AU BAUM, SA HECKMAN, TM VANBREUGEL, W AF BAUM, SA HECKMAN, TM VANBREUGEL, W TI SPECTROSCOPY OF EMISSION-LINE NEBULAE IN POWERFUL RADIO GALAXIES - INTERPRETATION SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES ISM; H-II REGIONS; ISM KINEMATICS AND DYNAMICS ID ACTIVE GALACTIC NUCLEI; COOLING FLOWS; ELLIPTICAL GALAXIES; SURFACE PHOTOMETRY; OPTICAL-SPECTRA; STAR FORMATION; IONIZED-GAS; LUMINOSITY; MORPHOLOGY; CLUSTERS AB We discuss our analysis of long-slit optical spectra of the emission-line nebulae associated with 21 low-redshift (z < 0.2) radio galaxies. We complement our data with similar data from the literature on 19 other low-redshift radio galaxies. We find that the nebulae can be classified kinematically into three types: rotators, calm nonrotators, and violent nonrotators. The kinematic classification correlates with the relative emission-line strengths in the nebulae and with the optical and radio properties of the galaxies. The nebulae in the rotator class have [O I] 6300 angstrom, [N II] 6584 angstrom, and [S II] 6717 angstrom emission lines that are weak relative to H-alpha. The rotators are nearly always associated with galaxies having luminous "high-ionization" nuclear emission-line regions and powerful edge-brightened (Fanaroff and Riley Class II) radio sources. The ionization of the nebulae in these sources is most likely dominated by photoionization from the nuclear continuum source. These galaxies usually inhabit regions of only modest galaxy density. Their radio jet and gas rotation axes are typically aligned to within 20-degrees. The calm nonrotator nebulae have [O I], [N II], and [S II] lines that are strong relative to H-alpha. They are preferentially associated with galaxies having "low-ionization" nuclear emission-line regions and less powerful, edge-dimmed (Fanaroff & Riley Class I) or amorphous radio sources. Heating and photoionization by the surrounding hot (10(7-8) K) ISM/ICM is likely to provide an important component of the ionization of the nebulae in these sources. These galaxies generally inhabit regions of high galaxy density. The violent nonrotators seem to be more similar to the rotators in their optical/radio properties, We propose that the rotators have dynamically young disks of gas recently acquired by the radio galaxy in an interaction or merger with a gas-rich galaxy. This is consistent with the data on the morphologies, colors, and stellar dynamics of radio galaxies with strong emission lines. This gas may fuel the nuclear activity and appears to be influential in the good collimation of these classical double (FRII class) radio sources. The calm nonrotators include seven radio galaxies with well-known "cooling flows." We suggest that these nebulae are in general the optical signature of a cooling flow which may fuel the active nucleus. The violent nonrotators may be related to the rotators, but either tidal forces or interactions with outflowing radio plasma have induced large noncircular motions in the ionized gas. The association of the large-scale gas kinematics with the radio and optical properties of the active galaxy then suggests that the angular momentum of the gas which fuels the AGN may be an important parameter in the determinant of how activity is manifest in an AGN. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP BAUM, SA (reprint author), NETHERLANDS FDN RES ASTRON,POSTBUS 2,7990 AA DWINGELOO,NETHERLANDS. NR 59 TC 120 Z9 120 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1992 VL 389 IS 1 BP 208 EP 222 DI 10.1086/171198 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM689 UT WOS:A1992HM68900015 ER PT J AU KETO, E BALL, R ARENS, J JERNIGAN, G MEIXNER, M AF KETO, E BALL, R ARENS, J JERNIGAN, G MEIXNER, M TI SUBARCSECOND MIDINFRARED IMAGING OF THE NUCLEI OF THE INFRARED BRIGHT GALAXIES NGC-1614 AND NGC-7469 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES INDIVIDUAL (NGC-1614, NGC-7469); GALAXIES NUCLEI; INFRARED GALAXIES; STARS FORMATION ID STAR FORMATION; APERTURE SYNTHESIS; GALACTIC NUCLEI; PHOTOMETRY; EMISSION; 10-MU-M AB We report on the first subarcsecond resolution mid-IR images of the nuclei of two galaxies from the IRAS bright sample, NGC 1614 and NGC 7469. Our results show that the starburst galaxy NGC 1614 contains a double structure in the nuclear region. Most of the flux, 78% of 650 +/- 50 mJy, is emitted in two unresolved regions of 0.6" FWHM (190 pc at 64 Mpc) of nearly equal strength separated by 0.6" (200 pc). Most of the remaining flux is derived from a small arm 1" in length (310 pc). The Seyfert I galaxy NGC 7469 shows an elongated structure, 1.4" x 0.7" (450 x 220 pc at 66 Mpc). C1 UNIV HAWAII,NASA,INFRARED TELESCOPE FACIL,HONOLULU,HI 96822. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94760. RP KETO, E (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 23 TC 23 Z9 23 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1992 VL 389 IS 1 BP 223 EP 226 DI 10.1086/171199 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM689 UT WOS:A1992HM68900016 ER PT J AU BROWN, LE AF BROWN, LE TI POSSIBLE SOURCES OF THE POPULATION-I LITHIUM ABUNDANCE AND LIGHT-ELEMENT EVOLUTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXY ABUNDANCES; GALAXY EVOLUTION; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES ID GALACTIC CHEMICAL EVOLUTION; HADRON PHASE-TRANSITION; METAL-DEFICIENT DWARFS; SOLAR NEIGHBORHOOD; PRIMORDIAL LITHIUM; NEUTRON DIFFUSION; NUCLEOSYNTHESIS; GALAXY; STARS; ORIGIN AB We examine one-zone numerical models of Galactic chemical evolution of the light elements (lithium, beryllium, boron, and deuterium) with a broad sample of possible stellar lithium production sites and star formation histories (including the multiple merger model of Mathews & Schramm. We investigate primordial values of Li-7/H = 10(-8) or 10(-10). Scenarios starting with primordial Li-7/H approximately 10(-10) are well fitted by several of our models. We obtain the best agreement with observations for star formation histories with an overall decrease in the star formation rate with time. Models with high primordial lithium are constrained by observations of lithium and potassium in the interstellar medium of the Large Magellanic Cloud (LMC) to have initial Li abundances close to the Population I value of approximately 10(-9). Li-7 production in intermediate- or high-mass stars (m > 4 M.) is found to fit observations somewhat better than production in low-mass (1 - 5 M.) stars. Since elevated levels of lithium are commonly observed in intermediate-mass stars in the LMC, it seems likely that this is indeed the major source of the Population I Li-7 abundance. The current predictions for low-level yields of Li-7 from supernova envelope shocks do not change these conclusions. C1 UNIV CHICAGO,CHICAGO,IL 60637. FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. NR 71 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1992 VL 389 IS 1 BP 251 EP 268 DI 10.1086/171202 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM689 UT WOS:A1992HM68900019 ER PT J AU RAFTERY, D LONG, H REVEN, L TANG, P PINES, A AF RAFTERY, D LONG, H REVEN, L TANG, P PINES, A TI NMR OF OPTICALLY PUMPED XENON THIN-FILMS SO CHEMICAL PHYSICS LETTERS LA English DT Article AB NMR of Xe-129 has been observed in thin films of xenon frozen onto the surfaces of glass sample cells with various geometries. The Xe-129 polarization was enhanced by optical pumping, and the xenon was then transferred to a high-field pulsed NMR spectrometer allowing the observation of strong signals from xenon films of approximately 1-mu-m thickness. The line shape depends on the film geometry because of the bulk diamagnetic susceptibility chi(D) of solid xenon. The spectral line shape and resonance frequency also depend on temperature. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP RAFTERY, D (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Reven, Linda/F-3679-2011 NR 25 TC 29 Z9 29 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 10 PY 1992 VL 191 IS 5 BP 385 EP 390 DI 10.1016/0009-2614(92)85396-R PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HP501 UT WOS:A1992HP50100002 ER PT J AU HEMBERGER, PH NOGAR, NS WILLIAMS, JD COOKS, RG SYKA, JEP AF HEMBERGER, PH NOGAR, NS WILLIAMS, JD COOKS, RG SYKA, JEP TI LASER PHOTODISSOCIATION PROBE FOR ION TOMOGRAPHY STUDIES IN A QUADRUPOLE ION-TRAP MASS-SPECTROMETER SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DENSITY DISTRIBUTION; GAS AB Ion tomography studies based on spatially resolved photodissociation of benzoyl cation (C6H5CO+) in an ion-trap mass spectrometer are presented. Changes in radially averaged parent ion distributions are observed as a function of applied RF potential during photodissociation and under conditions of resonant excitation with a supplementary ac voltage. This work also demonstrates stabilization of ion trajectories by helium buffer gas when the trap is used in the mass-selective instability mode of operation. C1 PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. FINNIGAN MAT CORP,SAN JOSE,CA 95134. RP HEMBERGER, PH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87545, USA. RI Cooks, R/G-1051-2015 OI Cooks, R/0000-0002-9581-9603 NR 29 TC 51 Z9 51 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 10 PY 1992 VL 191 IS 5 BP 405 EP 410 DI 10.1016/0009-2614(92)85400-5 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HP501 UT WOS:A1992HP50100006 ER PT J AU AUDUNSSON, H LEVI, S HODGES, F AF AUDUNSSON, H LEVI, S HODGES, F TI MAGNETIC PROPERTY ZONATION IN A THICK LAVA FLOW SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID FE-TI OXIDES; ALTERNATING-FIELD; OXYGEN FUGACITY; BASALT AB In this study, grain size and composition-dependent magnetic properties of titanomagnetite minerals are used as indicators of intraflow structures and magmatic evolution in an extensive and thick (30-60 m) basaltic lava flow. Similar zonation occurs in this flow at three localities separated by tens of kilometers. The magnetic properties subdivide the flow to three zones. The upper layer, representing the top 1/3 of the lava (less-than-or-equal-to 20 m), has higher magnetic stability due to smaller and more deuterically oxidized titanomagnetite grains, approaching pure magnetite. The central layer in the underlying 2/3 of the flow (less-than-or-equal-to 35 m) has larger, magnetically less stable, and less oxidized grains with relatively uniform magnetic properties. The basal layer, the bottom 1/10 of the flow (less-than-or-equal-to 5 m), has near primary, least oxidized titanomagnetites (Ulv68Mag32). The upper intraflow boundary of the magnetic properties appears to coincide with the transition from entablature (above) to colonnade (below), distinguishing between regions of faster and slower cooling. Microprobe data indicate that the intraflow-oxidation state (Fe3+/Fe2+) of the initially precipitated primary titanomagnetites increases with falling equilibrium temperature from the flow margins to a maximum near the center, the position of lowest equilibrium temperature. In contrast, Curie temperature measurements indicate that titanomagnetite oxidation increases with height in the flow. Modification of the initially symmetric equilibrium titanomagnetite compositions was caused by subsolidus high-temperature oxidation possibly due to hydrogen loss produced by dissociation of magmatic water, as well as unknown contributions of circulating air and percolating water from above. The titanomagnetites of the basal layer of the flow remain essentially unaltered. C1 OREGON STATE UNIV, COLL OCEANOG, CORVALLIS, OR 97331 USA. PACIFIC NW LAB, RICHLAND, WA USA. NR 46 TC 14 Z9 14 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1992 VL 97 IS B4 BP 4349 EP 4360 DI 10.1029/91JB01508 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HQ336 UT WOS:A1992HQ33600003 ER PT J AU GIBSON, RG NANEY, MT AF GIBSON, RG NANEY, MT TI TEXTURAL DEVELOPMENT OF MIXED, FINELY PORPHYRITIC SILICIC VOLCANIC-ROCKS, INYO DOMES, EASTERN CALIFORNIA SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID LONG-VALLEY CALDERA; OBSIDIAN DOME; GRANITIC SYSTEMS; GLASS MOUNTAIN; MAGMA; EMPLACEMENT; CHAIN; CRYSTALLIZATION; CONSTRAINTS; THERMOMETRY AB Magma mixing in silicic volcanic rocks of the Inyo chain is manifest by bimodal mineral chemistry and distinctive banding, defined by either variations in (1) glass color and chemistry or (2) microlite abundance within colorless glass. Bands composed of brown or microlite-rich, colorless glass are characterized by more Mg-rich mafic silicates and more calcic plagioclase than microlite-poor, colorless glass domains. A rhyolitic and a dacitic mixing end-member can be defined on the basis of this mineral distribution. Thermobarometry using the mineral assemblages unique to each end-member indicates that prior to mixing, the dacite was more oxidized and water-rich than the rhyolitic magma. Determined mineral crystallization conditions compare favorably with experimentally derived phase equilibria for melts of broadly similar composition. The spatial association of contrasting mineral assemblages with the flow banding in these rocks implies that the banding is a direct product of magma mixing. It formed as either (1) volumes of the comingled magmas were immediately vented to the surface and quenched, preserving domains of two distinct glass compositions, or (2) bands of dacitic magma precipitated microlites when comingled with the rhyolitic magma in an attempt for the two magmas to approach equilibrium. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP GIBSON, RG (reprint author), AMOCO PROD CO,RES,POB 3385,TULSA,OK 74102, USA. NR 49 TC 11 Z9 11 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1992 VL 97 IS B4 BP 4541 EP 4559 DI 10.1029/91JB03063 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HQ336 UT WOS:A1992HQ33600016 ER PT J AU BENZ, HM ZANDT, G OPPENHEIMER, DH AF BENZ, HM ZANDT, G OPPENHEIMER, DH TI LITHOSPHERIC STRUCTURE OF NORTHERN CALIFORNIA FROM TELESEISMIC IMAGES OF THE UPPER MANTLE SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID ANDREAS FAULT ZONE; GORDA PLATE; TRAVEL-TIMES; TOMOGRAPHIC IMAGE; CRUSTAL STRUCTURE; TRIPLE JUNCTION; VOLCANIC-ROCKS; BENEATH; SUBDUCTION; WASHINGTON AB Teleseismic P wave travel time residuals from 120 earthquakes recorded across the U.S. Geological Survey California seismic network were used to determine the lithosphere P wave velocity structure beneath northern California, a region characterized by complex interactions between the Pacific, North American, and Gorda plates. Lateral P wave velocity variations beneath the array were determined by inversion of 9383 travel time residuals. Inversion results for the crust show strong correlations to volcanic features. The active volcanic fields, Shasta-Medicine Lake, Lassen, and Clear Lake, are characterized by crustal low-velocity anomalies that average approximately -6%, possibly identifying partially molten magma bodies. Cooled, solidified magma bodies beneath the extinct volcanic fields, Sonoma, southern Clear Lake, and Sutter Buttes, are denoted by relative velocity highs averaging +3%. The largest upper mantle velocity variations occur in the depth range 30-110 km, where velocities vary from -5.5% to +9.5%. These velocity variations reflect changes in the thickness and geometry of the Pacific, North American, and Gorda plates where they interact at the Mendocino Triple Junction. North of the Mendocino Triple Junction, the steep 70-degrees east dipping portion of the Gorda plate is imaged as a +5% velocity high to depths near 270 km. A presumed segment of the Gorda plate, observed beneath the northern Great Valley and south of the inferred edge of the plate, is characterized by a +9% velocity high in the depth range 30-70 km. Beneath the northern Coast Ranges, shallow asthenosphere is imaged in the depth range 30-100 km as a pronounced southward tapering -4% low-velocity zone, which we interpret as the slab window. Results from this study provide improved constraints on Gorda plate subduction, evolution of the San Andreas fault system, and development of the lithosphere beneath western North America. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,IGPP CTR GEOSCI L-202,LIVERMORE,CA 94550. RP BENZ, HM (reprint author), US GEOL SURVEY,345 MIDDLEFIELD RD,MS 977,MENLO PK,CA 94025, USA. OI Oppenheimer, David/0000-0002-6569-3640 NR 48 TC 98 Z9 99 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1992 VL 97 IS B4 BP 4791 EP 4807 DI 10.1029/92JB00067 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HQ336 UT WOS:A1992HQ33600030 ER PT J AU KIM, KJ FANE, AG FELL, CJD JOY, DC AF KIM, KJ FANE, AG FELL, CJD JOY, DC TI FOULING MECHANISMS OF MEMBRANES DURING PROTEIN ULTRAFILTRATION SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE FOULING; MICROFILTRATION; ULTRAFILTRATION; ELECTRON MICROSCOPY ID COTTAGE CHEESE WHEY; PRETREATMENT; ADSORPTION AB Fouling mechanisms of various ultrafiltration membranes were studied by high resolution field emission scanning electron microscopic (FESEM) examination of deposits formed during ultrafiltration of albumin protein. Fouling appears to be a surface phenomenon even for membranes that pass substantial amounts of protein. There was no FESEM observable protein within the pores. Two different types of foulant deposit were observed on the membrane surface; fouling by multilayer (cake) coating and fouling by aggregates of proteins. While aggregating type fouling was observed for membranes with high initial UF fluxes, those with lower initial UF flux showed cake formation. Aggregation may be initiated by rapid supersaturation of proteins above the pores due to high convective flows. C1 UNIV NEW S WALES,CTR MEMBRANE & SEPARAT TECHNOL,POB 1,KENSINGTON,NSW 2033,AUSTRALIA. UNIV TENNESSEE,EM FACIL,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. NR 32 TC 116 Z9 125 U1 2 U2 27 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD APR 10 PY 1992 VL 68 IS 1-2 BP 79 EP 91 PG 13 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA HR263 UT WOS:A1992HR26300007 ER PT J AU JANKOWSKI, AF AF JANKOWSKI, AF TI A15 STRUCTURE FORMATION IN TI-PD SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article ID ALLOYS AB Vapor phase formation of thin films in the Ti-Pd alloy system is investigated using magnetron sputter deposition. Crystalline as-deposited structures are produced with nominal compositions of 20, 25 and 30 at.%Pd. The high temperature b.c.c. phase is produced on room temperature substrates via quenching from the vapor phase. An A15 structure of Ti3Pd is rigorously identified for the first time, in agreement with predictions from electronic structure calculations. RP JANKOWSKI, AF (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 9 PY 1992 VL 182 IS 1 BP 35 EP 42 DI 10.1016/0925-8388(92)90571-P PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA HP945 UT WOS:A1992HP94500004 ER PT J AU ZUNDELEVICH, Y AF ZUNDELEVICH, Y TI THE MEDIATED ELECTROCHEMICAL DISSOLUTION OF PLUTONIUM OXIDE - KINETICS AND MECHANISM SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article AB The design and optimization of large-scale systems for electrochemical dissolution of PuO2 in the presence of Ag2+ ions acting as mediators require a knowledge of true dissolution kinetics, usually obscured by limiting capacities of the electrolytic cells. Analysis conducted in this study identified the PuO2 surface reaction with silver(II) as the rate-controlling step and led to a mathematical model of the process based on first-order heterogeneous kinetics. By applying the model for simulation of a large-scale PuO2 dissolution experiment reported by Bourges et al., a first-order rate constant k = 0.0004 cm min-1 for electrochemical dissolution of PuO2 at 25-degrees-C has been determined. The model was then used to demonstrate the strong effects of the PuO2 size distribution, the silver(I) concentration, the anodic current and some other operational parameters on the dissolution time and the current efficiency. The results of this investigation provide a means for rational design and operation of plutonium-processing systems and stress the importance of operation at the limiting current. RP ZUNDELEVICH, Y (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-367,LIVERMORE,CA 94550, USA. NR 9 TC 11 Z9 11 U1 1 U2 10 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 9 PY 1992 VL 182 IS 1 BP 115 EP 130 DI 10.1016/0925-8388(92)90580-3 PG 16 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA HP945 UT WOS:A1992HP94500013 ER PT J AU DEXHEIMER, SL KLEIN, MP AF DEXHEIMER, SL KLEIN, MP TI DETECTION OF A PARAMAGNETIC INTERMEDIATE IN THE S1-STATE OF THE PHOTOSYNTHETIC OXYGEN-EVOLVING COMPLEX SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID RAY ABSORPTION-SPECTROSCOPY; WATER-SPLITTING ENZYME; PHOTOSYSTEM-II; RES SIGNAL; O-2-EVOLVING COMPLEX; ELECTRON-TRANSPORT; MANGANESE COMPLEX; S2 STATE; S1 STATE; EVOLUTION AB We report the detection of a new electron paramagnetic resonance (EPR) signal that demonstrates the presence of a paramagnetic intermediate in the resting (S1) state of the photosynthetic oxygen-evolving complex. The signal was detected using the method of parallel polarization EPR, which is sensitive to DELTA-m = 0 transitions in high spin systems. The properties of the parallel polarization EPR signal in the S1 state are consistent with an S = 1 spin state of an exchange-Coupled manganese center that corresponds to the reduced form of the species giving rise to the multiline EPR signal in the light-induced S2 state. The implications for the electronic structure of the oxygen-evolving complex are discussed. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. NR 47 TC 117 Z9 119 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 8 PY 1992 VL 114 IS 8 BP 2821 EP 2826 DI 10.1021/ja00034a010 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA HM897 UT WOS:A1992HM89700010 ER PT J AU DOORN, SK STOUTLAND, PO DYER, RB WOODRUFF, WH AF DOORN, SK STOUTLAND, PO DYER, RB WOODRUFF, WH TI PICOSECOND INFRARED STUDY OF ULTRAFAST ELECTRON-TRANSFER AND VIBRATIONAL-ENERGY RELAXATION IN A MIXED-VALENT RUTHENIUM DIMER SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID NON-RRKM DECOMPOSITION; STATE-TO-STATE; COMPLEXES; EXCITATION C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,MAIL STOP J-567,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV INORGAN & NUCL CHEM,LOS ALAMOS,NM 87545. NR 22 TC 64 Z9 64 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 8 PY 1992 VL 114 IS 8 BP 3133 EP 3134 DI 10.1021/ja00034a067 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA HM897 UT WOS:A1992HM89700067 ER PT J AU DEBOER, RJ SEGEL, LA PERELSON, AS AF DEBOER, RJ SEGEL, LA PERELSON, AS TI PATTERN-FORMATION IN ONE-DIMENSIONAL AND 2-DIMENSIONAL SHAPE-SPACE MODELS OF THE IMMUNE-SYSTEM SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID CLONAL SELECTION; IDIOTYPIC NETWORKS; 3-DIMENSIONAL STRUCTURE; ANTIBODY REPERTOIRE; MATHEMATICAL MODEL; SOMATIC MUTATION; CELL-SURFACE; COMPLEX; DYNAMICS; ANTIGEN C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. WEIZMANN INST SCI,DEPT APPL MATH & COMP SCI,IL-76100 REHOVOT,ISRAEL. RI De Boer, Rob/B-6050-2011 OI De Boer, Rob/0000-0002-2130-691X FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI 28433] NR 45 TC 77 Z9 79 U1 1 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD APR 7 PY 1992 VL 155 IS 3 BP 295 EP 333 DI 10.1016/S0022-5193(05)80601-0 PG 39 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA HP649 UT WOS:A1992HP64900003 PM 1619955 ER PT J AU CHUNG, BC VIRSHUP, GF KLAUSMEIERBROWN, M RISTOW, ML WANLASS, MW AF CHUNG, BC VIRSHUP, GF KLAUSMEIERBROWN, M RISTOW, ML WANLASS, MW TI 25.2-PERCENT EFFICIENCY (1-SUN, AIR MASS-0) ALGAAS/GAAS/INGAASP 3-JUNCTION, 2-TERMINAL SOLAR-CELL SO APPLIED PHYSICS LETTERS LA English DT Article ID SUN AB A 25.2% efficiency measured under 1 sun, air mass 0 illumination has been achieved in a two-terminal AlGaAs/GaAs/InGaAsP three-junction solar cell. The cascade cell consists of a monolithic AlGaAs (E(g) = 1.93 eV)/GaAs two-junction mechanically stacked on an InGaAsP (E(g) = 0.95 eV) single-junction cell. The component cell of the AlGaAs/GaAs two-junction structure were electrically connected using a metal interconnect fabricated during post-growth processing. To minimize the obscuration effect introduced by the grid lines and metal interconnect, a prismatic cover glass was bonded to the AlGaAs/GaAs cascade cell. The results obtained with this structure represent the highest 1-sun, air mass 0 efficiency achieved in any solar cell operating under a two-terminal configuration. The implications of achieving this high efficiency in a two-terminal, three-junction solar cell for terrestrial and space applications are described as well. C1 VS CORP,SAN JOSE,CA 95129. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP CHUNG, BC (reprint author), VARIAN RES CTR,PALO ALTO,CA 94304, USA. NR 7 TC 10 Z9 11 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 6 PY 1992 VL 60 IS 14 BP 1691 EP 1693 DI 10.1063/1.107213 PG 3 WC Physics, Applied SC Physics GA HM466 UT WOS:A1992HM46600015 ER PT J AU SEAGER, CH VENTURINI, EL SCHUBERT, WK AF SEAGER, CH VENTURINI, EL SCHUBERT, WK TI SPIN DEPENDENT PHOTOCURRENTS IN RIBBON SOLAR-CELLS SO APPLIED PHYSICS LETTERS LA English DT Article ID GRAIN-BOUNDARY RECOMBINATION; HYDROGEN PASSIVATION; SILICON; JUNCTION; SEMICONDUCTORS AB Microwave resonance induced variations in the short circuit photocurrent of edge-defined film-fed growth ribbon silicon solar cells have been observed. These signals have zero-crossing g values and linewidths which are similar to electron spin resonance and spin dependent transport (SDT) observations on silicon bicrystals, damaged silicon, and polycrystalline silicon. The SDT signals seen here depend on cell illumination levels in a way that suggests that the values of recombination velocity at electrically active linear boundaries decrease with illumination intensity. Hydrogen processed cells show markedly smaller SDT response, consistent with the passivation of Si dangling bond defects. While only dangling bond SDT response is apparent at 300 K, we suggest that similar experiments performed at low temperatures may have the resolution to identify the centers responsible for the majority of the electron-hole recombination events in these cells. RP SEAGER, CH (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 20 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 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 6 PY 1992 VL 60 IS 14 BP 1732 EP 1734 DI 10.1063/1.107200 PG 3 WC Physics, Applied SC Physics GA HM466 UT WOS:A1992HM46600029 ER PT J AU KRISHNAN, KM MENON, ESK HUANG, P SINGH, PP DEFONTAINE, D AF KRISHNAN, KM MENON, ESK HUANG, P SINGH, PP DEFONTAINE, D TI SHORT-RANGE ORDER EFFECTS ON COPPER L(3,2) TRANSITIONS IN CU-PD ALLOYS SO APPLIED PHYSICS LETTERS LA English DT Article ID STATES; BAND AB The unoccupied d-electron density of states of a range of Cu1-xPdx (x = 0 - 0.35) alloys, based on measurements of copper L3,2 transitions in electron energy-loss spectroscopy, is shown to be critically dependent on short-range order. This finding is supported by band structure calculations where the d-hole count at the Cu site for disordered alloys is found to be independent of the composition. Based on the above, a linear correlation between the degree of short-range order, as defined by the splitting of the diffuse maxima in the diffraction patterns, and the d-band occupancy has been established. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP KRISHNAN, KM (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 9 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 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 6 PY 1992 VL 60 IS 14 BP 1762 EP 1764 DI 10.1063/1.107210 PG 3 WC Physics, Applied SC Physics GA HM466 UT WOS:A1992HM46600039 ER PT J AU BURKARDT, M AF BURKARDT, M TI THE PHOTON DISTRIBUTION OF ATOMS AND MOLECULES SO NUCLEAR PHYSICS B LA English DT Article ID GLUON DISTRIBUTIONS; SMALL-X; RECOMBINATION AB In the weak coupling limit of QED, it is shown how to express the parton distributions - in particular the photon distribution - in terms of the non-relativistic wave functions. A sum rule is derived, relating the momentum carried by the photons to the binding energy, thus allowing quantitative predictions about the modification of the photon distribution as molecules are formed from atoms. The physical content is illustrated in a semi-classical picture as well as by providing analytic results for positronium. RP BURKARDT, M (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305, USA. NR 28 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 6 PY 1992 VL 373 IS 2 BP 371 EP 395 DI 10.1016/0550-3213(92)90437-G PG 25 WC Physics, Particles & Fields SC Physics GA HP994 UT WOS:A1992HP99400003 ER PT J AU ALBRECHT, A STEBBINS, A AF ALBRECHT, A STEBBINS, A TI PERTURBATIONS FROM COSMIC STRINGS IN COLD DARK MATTER SO PHYSICAL REVIEW LETTERS LA English DT Article ID GALAXY FORMATION; DENSITY-FLUCTUATIONS; SCALE STRUCTURE; EVOLUTION; UNIVERSE AB We present a systematic linear analysis of the perturbations induced by cosmic strings in cold dark matter. We calculate the power spectrum and find that the strings produce a great deal of power on small scales. We show that the perturbations on interesting scales are the result of many uncorrelated string motions, which indicates a more "Gaussian" distribution than was previously supposed. RP ALBRECHT, A (reprint author), NASA,FERMILAB ASTROPHYS CTR,POB 500,BATAVIA,IL 60510, USA. NR 25 TC 70 Z9 70 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 1992 VL 68 IS 14 BP 2121 EP 2124 DI 10.1103/PhysRevLett.68.2121 PG 4 WC Physics, Multidisciplinary SC Physics GA HM440 UT WOS:A1992HM44000004 ER PT J AU NELSON, JS FEIBELMAN, PJ AF NELSON, JS FEIBELMAN, PJ TI CALCULATION OF THE STRUCTURE OF THE AL(331) STEPPED SURFACE SO PHYSICAL REVIEW LETTERS LA English DT Article ID THIN METAL-FILMS; MULTILAYER RELAXATION; DENSITY; ALUMINUM AB Car-Parinello-like calculations have been used to compute the relaxation of the Al(331) surface, with results that are in remarkable agreement with the low energy electron diffraction analysis of Adams and Sorenson. Rapid screening of the steps on Al(331) is illustrated by comparing its charge density and relaxations to those of Al(110) and Al(111). RP NELSON, JS (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 16 TC 50 Z9 50 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 1992 VL 68 IS 14 BP 2188 EP 2191 DI 10.1103/PhysRevLett.68.2188 PG 4 WC Physics, Multidisciplinary SC Physics GA HM440 UT WOS:A1992HM44000021 ER PT J AU SANDY, AR MOCHRIE, SGJ ZEHNER, DM GRUBEL, G HUANG, KG GIBBS, D AF SANDY, AR MOCHRIE, SGJ ZEHNER, DM GRUBEL, G HUANG, KG GIBBS, D TI RECONSTRUCTION OF THE PT(111) SURFACE SO PHYSICAL REVIEW LETTERS LA English DT Article ID COMMENSURATE-INCOMMENSURATE TRANSITION; X-RAY-SCATTERING; AU(001) SURFACE; DISLOCATIONS; PLATINUM; IRIDIUM; PHASES; LIQUID; GOLD AB The structure of the clean Pt(111) surface has been studied between 300 K and 0.92T(m) (T(m) = 2045 K) via x-ray scattering. The surface is unreconstructed for temperatures less than 0.65T(m), but reconstructs at higher temperatures to form a layer isotropically compressed and incommensurate with the underlying bulk (111) planes. A disordered arrangement of discommensurations separates regions with ideal fcc stacking from regions with faulted stacking. With increasing temperature both the compression of the surface layer and the orientational order of the discommensurations increase. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP SANDY, AR (reprint author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA. NR 22 TC 109 Z9 109 U1 1 U2 16 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 1992 VL 68 IS 14 BP 2192 EP 2195 DI 10.1103/PhysRevLett.68.2192 PG 4 WC Physics, Multidisciplinary SC Physics GA HM440 UT WOS:A1992HM44000022 ER PT J AU MALSHUKOV, AG MAHAN, GD AF MALSHUKOV, AG MAHAN, GD TI MAGNON RENORMALIZATION OF A LOCALIZED HOLE SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-J MODEL; ORTHOGONALITY CATASTROPHE; GROUND-STATE; SINGLE HOLE; ANTIFERROMAGNET; SUPERCONDUCTORS; MOTION; METALS; BAND AB The exact quasiparticle renormalization is calculated for a localized hole in a quantum Heisenberg antiferromagnet. A bound magnon pole causes large increases in the quasiparticle renormalization. However, the renormalization remains finite. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP MALSHUKOV, AG (reprint author), ACAD SCI USSR,INST SPECT,TROITSK 142092,USSR. NR 22 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 1992 VL 68 IS 14 BP 2200 EP 2203 DI 10.1103/PhysRevLett.68.2200 PG 4 WC Physics, Multidisciplinary SC Physics GA HM440 UT WOS:A1992HM44000024 ER PT J AU BARTYNSKI, RA YANG, S HULBERT, SL KAO, CC WEINERT, M ZEHNER, DM AF BARTYNSKI, RA YANG, S HULBERT, SL KAO, CC WEINERT, M ZEHNER, DM TI SURFACE ELECTRONIC-STRUCTURE AND OFF-SITE AUGER TRANSITIONS ON TAC(111) OBSERVED WITH AUGER-PHOTOELECTRON COINCIDENCE SPECTROSCOPY SO PHYSICAL REVIEW LETTERS LA English DT Article ID DESORPTION; CHARGE; TACX AB The Ta N7VV Auger spectrum of TaC(111) has been measured in coincidence with photoemission from the bulk and surface shifted Ta 4f7/2 core levels. Good agreement is found between the surface Auger spectrum and a self-convolution of the density of states (SCDOS) at surface Ta sites determined by a first-principles calculation. The bulk spectrum disagrees with the bulk SCDOS but is well described by an incoherent sum of the bulk SCDOS and the surface spectrum. A novel off-site Auger decay mechanism, first observed on Ta(100), accounts for these observations. C1 BROOKHAVEN NATL LAB, NATL SYNCHROTRON LIGHT SOURCE, UPTON, NY 11973 USA. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. RP RUTGERS UNIV STATE UNIV, DEPT PHYS & ASTRON, POB 849, PISCATAWAY, NJ 08855 USA. NR 22 TC 30 Z9 30 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 1992 VL 68 IS 14 BP 2247 EP 2250 DI 10.1103/PhysRevLett.68.2247 PG 4 WC Physics, Multidisciplinary SC Physics GA HM440 UT WOS:A1992HM44000036 ER PT J AU KIM, L CAO, W CHEN, E HUNT, A AF KIM, L CAO, W CHEN, E HUNT, A TI AEROGEL - USE OF SOL-GEL PROCESSING TO PRODUCE A HIGH-PERFORMANCE MATERIAL SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 1 EP IEC PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK162 UT WOS:A1992HK16200029 ER PT J AU WYMAN, CE AF WYMAN, CE TI MICROBIAL CONVERSION OF RENEWABLE RESOURCES INTO FUELS, CHEMICALS, AND MATERIALS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 1 EP BIOT PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16100527 ER PT J AU CASEY, WH BANFIELD, JF WESTRICH, HR AF CASEY, WH BANFIELD, JF WESTRICH, HR TI REACTIVITY TRENDS IN ORTHOSILICATE WEATHERING SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV WISCONSIN,DEPT GEOL,MADISON,WI 53706. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 2 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16102472 ER PT J AU EHLER, DS SAUER, NN FRANKCOM, TM AF EHLER, DS SAUER, NN FRANKCOM, TM TI TREATMENT OF URANIUM AND LEAD FOR WASTE-DISPOSAL SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPE & NUCL CHEM,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 2 EP TECH PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16101468 ER PT J AU MARTIN, RL AF MARTIN, RL TI ABINITIO CLUSTER STUDIES OF LA2CUO4 SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 5 EP COMP PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16101890 ER PT J AU BROWN, NJ GARAY, J AF BROWN, NJ GARAY, J TI MODELING AND SENSITIVITY ANALYSIS STUDY OF THE SELECTIVE REDUCTION OF NOX BY HNCO SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 6 EP IEC PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK162 UT WOS:A1992HK16200034 ER PT J AU HARPEL, MR LARIMER, FW LEE, EH MURAL, RJ SOPER, TS HARTMAN, FC AF HARPEL, MR LARIMER, FW LEE, EH MURAL, RJ SOPER, TS HARTMAN, FC TI FUNCTIONAL-SIGNIFICANCE OF INTERSUBUNIT ELECTROSTATIC INTERACTIONS AT THE ACTIVE-SITE OF R-RUBRUM RIBULOSE-BISPHOSPHATE (RUBP) CARBOXYLASE OXYGENASE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN 37831. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 6 EP BIOL PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16100676 ER PT J AU THOMPSON, LH WEBER, CA FELTON, JS AF THOMPSON, LH WEBER, CA FELTON, JS TI DNA-REPAIR PATHWAYS AS A MAJOR MODULATOR OF MUTAGENESIS AND CARCINOGENESIS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 7 EP CHAS PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16101366 ER PT J AU FELTON, JS KNIZE, MG BUONARATI, MH THOMPSON, LH TURTELTAUB, KW AF FELTON, JS KNIZE, MG BUONARATI, MH THOMPSON, LH TURTELTAUB, KW TI GENOTOXICITY AND DNA-BINDING OF MUTAGENS CARCINOGENS IN COOKED FOOD SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 8 EP CHAS PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16101367 ER EF