FN Thomson Reuters Web of Science™ VR 1.0 PT J AU KORNEEV, VA JOHNSON, LR AF KORNEEV, VA JOHNSON, LR TI SCATTERING OF ELASTIC-WAVES BY A SPHERICAL INCLUSION .1. THEORY AND NUMERICAL RESULTS SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE ELASTIC WAVES; DIFFRACTION; SCATTERING; SPHERE ID BORN APPROXIMATION; MATRIX; FLAWS AB A complete and exact solution for the problem of an incident P wave scattered by an elastic spherical inclusion is presented and described. The solution can be obtained from either analytical formulae or stable numerical procedures. A method of estimating the number of terms that must be retained in the harmonic series in order to achieve a specified accuracy is given. The results are investigated by calculating synthetic seismograms, scattering diagrams, and scattering cross-sections for a broad frequency band and for both low-velocity and high-velocity inclusions. The fields within the shadow zone are formed primarily from three different types of waves, P waves transmitted through the sphere, P waves diffracted around the sphere, and S waves converted at the boundary of the sphere. The relative contribution from these different waves depends upon the distance of the observation point from the sphere. C1 LAWRENCE BERKELEY LAB, CTR COMP SEISMOL, BERKELEY, CA 94720 USA. RP KORNEEV, VA (reprint author), LAWRENCE BERKELEY LAB, DEPT GEOL & GEOPHYS, BERKELEY, CA 94720 USA. NR 37 TC 29 Z9 30 U1 1 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X EI 1365-246X J9 GEOPHYS J INT JI Geophys. J. Int. PD OCT PY 1993 VL 115 IS 1 BP 230 EP 250 DI 10.1111/j.1365-246X.1993.tb05601.x PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LZ782 UT WOS:A1993LZ78200017 ER PT J AU KORNEEV, VA JOHNSON, LR AF KORNEEV, VA JOHNSON, LR TI SCATTERING OF ELASTIC-WAVES BY A SPHERICAL INCLUSION .2. LIMITATIONS OF ASYMPTOTIC SOLUTIONS SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE DIFFRACTION; ELASTIC WAVES; SCATTERING; SPHERE ID ATTENUATION AB Starting with the exact solution for the scattering of a plane P wave by a homogeneous spherical inclusion, various types of approximate solutions are developed and discussed. The standard Rayleigh and Mie approximations are extended to the case of inclusions having arbitrary contrasts in material properties. For the low-contrast case, solutions are developed which are valid over a wide frequency range. Several aspects of these solutions are discussed, including the importance of near-field terms and the relative strength of the scattered P and S fields. The various types of approximate solutions are compared with each other and with the exact solution by calculating and displaying their normalized scattering cross-sections. C1 LAWRENCE BERKELEY LAB, CTR COMP SEISMOL, BERKELEY, CA 94720 USA. RP LAWRENCE BERKELEY LAB, DEPT GEOL & GEOPHYS, BERKELEY, CA 94720 USA. NR 10 TC 25 Z9 26 U1 0 U2 6 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X EI 1365-246X J9 GEOPHYS J INT JI Geophys. J. Int. PD OCT PY 1993 VL 115 IS 1 BP 251 EP 263 DI 10.1111/j.1365-246X.1993.tb05602.x PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LZ782 UT WOS:A1993LZ78200018 ER PT J AU REVZAN, KL FISK, WJ SEXTRO, RG AF REVZAN, KL FISK, WJ SEXTRO, RG TI MODELING RADON ENTRY INTO FLORIDA SLAB-ON-GRADE HOUSES SO HEALTH PHYSICS LA English DT Article DE RADON; SOIL; TRANSPORTATION; MODELING ID AIR-FLOW; BUILDINGS AB Radon entry into a Florida house whose concrete slab is supported by a permeable concrete-block stem wall and a concrete footer is modeled. The slab rests on backfill material; the same material is used to fill the footer trench. A region of undisturbed soil is assumed to extend 10 m beyond and below the footer. The soil is assumed homogeneous and isotropic except for certain simulations in which soil layers of high permeability or radium content are introduced. Depressurization of the house induces a pressure field in the soil and backfill. The Laplace equation, resulting from Darcy's law and the continuity equation, is solved using a steady-state finite-difference model to determine this field. The mass-transport equation is then solved to obtain the diffusive and advective radon entry rates through the slab; the permeable stem wall; gaps at the intersections of the slab, stem wall, and footer; and gaps in the slab. These rates are determined for variable soil, backfill, and stem-wall permeability and radium content, slab-opening width and position, slab and stem-wall diffusivity, and water table depth. The variations in soil permeability and radium content include cases of horizontally stratified soil. We also consider the effect of a gap between the edge of the slab and the stem wall that restricts the passage of soil gas from the stem wall into the house. Calculations indicate that the total radon entry rate is relatively low unless the soil or backfill permeability or radium content is high. Variations in most of the factors, other than the soil permeability and radium content, have only a small effect on the total radon entry rate. However, for a fixed soil permeability, the total radon entry rate may be reduced by a factor of 2 or more by decreasing the backfill permeability, by making the stem wall impermeable and pp-free, (possibly by constructing a one-piece slab/stem-wall/footer), or by increasing the pressure in the interior of the stem wall (by ensuring that there is a large pressure drop across the slab/stem-wall gap), thereby reducing radon entry into the wall from the soil. Use of an impermeable stem wall and a low-permeability fill in combination is predicted to reduce the radon entry rate by 71%. RP REVZAN, KL (reprint author), LAWRENCE BERKELEY LAB, DIV APPL SCI, INDOOR ENVIRONM PROGRAM, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 24 TC 12 Z9 12 U1 0 U2 3 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1993 VL 65 IS 4 BP 375 EP 385 DI 10.1097/00004032-199310000-00004 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA LZ437 UT WOS:A1993LZ43700004 PM 8376117 ER PT J AU STEWART, RD TANNER, JE LEONOWICH, JA AF STEWART, RD TANNER, JE LEONOWICH, JA TI AN EXTENDED TABULATION OF EFFECTIVE DOSE-EQUIVALENT FROM NEUTRONS INCIDENT ON A MALE ANTHROPOMORPHIC PHANTOM SO HEALTH PHYSICS LA English DT Article DE NEUTRON DOSIMETRY; DOSE EQUIVALENT, EFFECTIVE; DOSIMETRY, EXTERNAL; RADIATION PROTECTION AB The limiting quantity in radiation protection for whole body exposures in the United States is currently based on the effective dose equivalent (EDE). Because EDE is computed from the individual organ dose equivalents, it is essentially impossible to measure EDE directly. However, calculated organ dose equivalents, and the resulting EDE, can be correlated to the response of a detector located at one or more locations on the human body. Until now, calculations of the effective dose equivalent and corresponding organ dose equivalents have been tabulated for relatively few standard irradiation geometries and energies. In this work, a more extensive tabulation of EDE is compiled and compared to the works of other researchers. This tabulation includes calculations of the EDE for a total of 493 different combinations of source particle energy and angle of incidence. This extensive tabulation of the EDE should allow researchers to improve algorithms for the evaluation of neutron personnel dosimetry. RP STEWART, RD (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. RI Stewart, Robert/A-3609-2013 OI Stewart, Robert/0000-0001-5946-0595 NR 19 TC 14 Z9 14 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 OCT PY 1993 VL 65 IS 4 BP 405 EP 413 DI 10.1097/00004032-199310000-00008 PG 9 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 LZ437 UT WOS:A1993LZ43700008 PM 8376121 ER PT J AU NELSON, IC THOMAS, VW KATHREN, RL AF NELSON, IC THOMAS, VW KATHREN, RL TI PLUTONIUM IN SOUTH-CENTRAL WASHINGTON-STATE AUTOPSY TISSUE SAMPLES - 1970-1975 SO HEALTH PHYSICS LA English DT Article DE DOSE, INTERNAL; BIOASSAY; PLUTONIUM; CONTAMINATION, ENVIRONMENTAL AB Results are presented of postmortem human tissue sampling and analysis for plutonium of Hanford Site workers, residents of the nearby Tri-Cities, and individuals residing farther away from the Hanford Site for the period 1970-1975. The majority of Hanford Site workers and nearby residents coming to autopsy had tissue concentrations of plutonium no larger than those who lived farther away from Hanford and whose likely source of plutonium was limited to nuclear weapons testing fallout. Thus, Hanford operations up to that time apparently had made no significant addition to plutonium in those individuals sampled postmortem. C1 WASHINGTON STATE UNIV TRICITIES, US TRANSURANIUM & URANIUM REGISTRIES, RICHLAND, WA 99352 USA. RP NELSON, IC (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. RI WSU, USTUR/I-1056-2013 NR 10 TC 10 Z9 10 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1993 VL 65 IS 4 BP 422 EP 428 DI 10.1097/00004032-199310000-00011 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 LZ437 UT WOS:A1993LZ43700011 PM 8376124 ER PT J AU GAILEY, PC EASTERLY, CE AF GAILEY, PC EASTERLY, CE TI RESPONSE TO ADAIR EMP HEALTH-EFFECTS PAPER SO HEALTH PHYSICS LA English DT Letter RP GAILEY, PC (reprint author), OAK RIDGE NATL LAB, POB 2008, MAIL STOP 6101, OAK RIDGE, TN 37831 USA. NR 5 TC 1 Z9 5 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 OCT PY 1993 VL 65 IS 4 BP 437 EP 438 PG 2 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 LZ437 UT WOS:A1993LZ43700016 PM 8376127 ER PT J AU PANCHAL, CB RABAS, TJ AF PANCHAL, CB RABAS, TJ TI THERMAL PERFORMANCE OF ADVANCED HEAL EXCHANGERS FOR AMMONIA REFRIGERATION SYSTEMS SO HEAT TRANSFER ENGINEERING LA English DT Article AB Current practice in the ammonia industry is to use plain tubes. This article demonstrates that the coefficient of performance (COP) can be increased by about 11% using tubes with ammonia-side enhancement and by about 26% using tubes with ammonia-side and water-side enhancement. Further improvements with respect to energy and cost are possible with the compact heat exchanger types-plate-frame and plate-fin-because they can be optimized for the system conditions for each application. These findings are based on experimentally determined overall heat transfer coefficients that were obtained for candidate heat exchangers for the Ocean Thermal Energy Conversion (OTEC) program. RP PANCHAL, CB (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 29 TC 9 Z9 9 U1 0 U2 2 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD OCT-DEC PY 1993 VL 14 IS 4 BP 42 EP 57 DI 10.1080/01457639308939810 PG 16 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA MM245 UT WOS:A1993MM24500005 ER PT J AU RABAS, TJ PANCHAL, CB SASSCER, DS SCHAEFER, R AF RABAS, TJ PANCHAL, CB SASSCER, DS SCHAEFER, R TI COMPARISON OF RIVER-WATER FOULING RATES FOR SPIRALLY INDENTED AND PLAIN TUBES SO HEAT TRANSFER ENGINEERING LA English DT Article AB This article presents river-water fouling rates at 12 Tennessee Valley Authority (TVA) power plant condensers, nine of which were retubed with a commercially available enhanced tube. Four were located on the Cumberland River, six on the Ohio, and two on the Clinch River The overall heat transfer coefficients were calculated from logged field data taken over periods extending from 1 to 10 years. The fouling resistances were next calculated with the separate resistance method and with a bundle correction factor to the condensing, single-tube Nusselt prediction. The bundle correction factor was determined for each condenser using the data taken within 1000 hours after each cleaning. With the use of this new bundle factor method, fouling rate data can be obtained even with variable operating conditions. The fouling rates with the enhanced tubes ranged from about the same as to about twice that of the plain tubes. However, the thermal performance with the enhanced tubes remained superior to that obtained with plain tubes for more than a year without cleaning. Also after one year of operation, the enhanced-tube fouling resistance values were less than the minimum value of the TEMA Standards for river water, and the plain-tube fouling resistance values were always less than one-half of this value. After shutdown and brush and/or acid cleaning, the thermal performance values for both the plain and enhanced tubes were restored to essentially the new, clean levels. C1 NORTHWESTERN UNIV,EVANSTON,IL 60208. TENNESSEE VALLEY AUTHOR,CHATTANOOGA,TN 37402. RP RABAS, TJ (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 31 TC 13 Z9 18 U1 0 U2 0 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD OCT-DEC PY 1993 VL 14 IS 4 BP 58 EP 73 DI 10.1080/01457639308939811 PG 16 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA MM245 UT WOS:A1993MM24500006 ER PT J AU SHEN, Y HOLMAN, K DOGGETT, NA CALLEN, DF SUTHERLAND, GR RICHARDS, RI AF SHEN, Y HOLMAN, K DOGGETT, NA CALLEN, DF SUTHERLAND, GR RICHARDS, RI TI 4 DINUCLEOTIDE REPEAT POLYMORPHISMS ON HUMAN CHROMOSOME-16 SO HUMAN MOLECULAR GENETICS LA English DT Article C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. RP SHEN, Y (reprint author), ADELAIDE CHILDRENS HOSP INC,DEPT CYTOGENET & MOLEC GENET,ADELAIDE,SA 5006,AUSTRALIA. RI Sutherland, Grant/D-2606-2012; Callen, David/G-1975-2012 NR 2 TC 6 Z9 6 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0964-6906 J9 HUM MOL GENET JI Hum. Mol. Genet. PD OCT PY 1993 VL 2 IS 10 BP 1745 EP 1745 DI 10.1093/hmg/2.10.1745 PG 1 WC Biochemistry & Molecular Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Genetics & Heredity GA MC223 UT WOS:A1993MC22300044 PM 8268938 ER PT J AU WAHL, DE AF WAHL, DE TI TOWED ARRAY SHAPE ESTIMATION USING FREQUENCY-WAVE-NUMBER DATA SO IEEE JOURNAL OF OCEANIC ENGINEERING LA English DT Article DE SELF-SURVEY; SELF-COHERING; AND ARRAY SHAPE ESTIMATION ID SHARPNESS AB Towed array beamforming algorithms require accurate array shape information in order to perform properly. Very often, these algorithms assume the array is linear. Unfortunately, the mechanical forces on the array due to ship motion and sea dynamics can change the assumed shape of the array which consequently degrades the performance of the beamforming algorithm. This paper presents a data-driven approach to estimating the relative shape of a nominally linear array. The algorithm is robust in that it optimally combines information contained in a wide band of frequencies and source bearings. At the heart of the algorithm is a Maximum Likelihood (ML) estimation scheme. The Cramer-Rao Lower bound is derived and compared to the performance of the ML estimator. The utility of the algorithm is verified using both simulated and actual towed array data experiments. RP WAHL, DE (reprint author), SANDIA NATL LABS,TECH STAFF,DEPT ANAL 2,DIV 5912,ALBUQUERQUE,NM 87185, USA. NR 19 TC 16 Z9 18 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0364-9059 J9 IEEE J OCEANIC ENG JI IEEE J. Ocean. Eng. PD OCT PY 1993 VL 18 IS 4 BP 582 EP 590 DI 10.1109/48.262308 PG 9 WC Engineering, Civil; Engineering, Ocean; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA MX800 UT WOS:A1993MX80000021 ER PT J AU BAIRD, B HIRSCH, MW EECKMAN, F AF BAIRD, B HIRSCH, MW EECKMAN, F TI A NEURAL-NETWORK ASSOCIATIVE MEMORY FOR HANDWRITTEN CHARACTER-RECOGNITION USING MULTIPLE CHUA CHARACTERS SO IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING LA English DT Article ID EEG; PATTERNS; CORTEX AB A neural network architecture and learning algorithm for associative memory storage of analog patterns, continuous sequences, and chaotic attractors in the same is described. System performance using many different attractors from the family of Chua attractors the Chua hardware circuit is investigated in an the problem of real time handwritten digit recognition. of these attractors outperform the previously studied Lorenz attractor system in terms of accuracy and speed of convergence In the normal form projection algorithm, which was developed at Berkeley for associative memory storage of dynamic attractors, a matrix inversion determines network weights, given prototype patterns to be stored. There are N units of capacity in an N node network with 3N2 weights. It costs one unit per static two per Fourier component of each periodic trajectory, and least three per chaotic attractor. There are no spurious attractors and for periodic attractors there is a Liapunov function a special coordinate system which governs the approach transient states to stored trajectories. Unsupervised or supervised incremental learning algorithms for pattern classification, such as competitive learning or bootstrap Widrow-Hoff can easily be implemented. The architecture can be ''folded'' into a recurrent network with higher order weights that can be used as a model of cortex that stores oscillatory and chaotic attractors by a Hebb rule. A novel computing architecture has been constructed of recurrently interconnected associative memory modules of this Architectural variations employ selective synchronization of modules with chaotic attractors that communicate by broadspectrum chaotic signals to control the flow of computation. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP BAIRD, B (reprint author), UNIV CALIF BERKELEY,DEPT MATH,BERKELEY,CA 94720, USA. NR 24 TC 11 Z9 11 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1057-7130 J9 IEEE T CIRCUITS-II JI IEEE Trans. Circuits Syst. II-Analog Digit. Signal Process. PD OCT PY 1993 VL 40 IS 10 BP 667 EP 674 DI 10.1109/82.246169 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA MK911 UT WOS:A1993MK91100010 ER PT J AU FORSYTH, EB AF FORSYTH, EB TI THE AGING OF ELECTRICAL INSULATION AT CRYOGENIC TEMPERATURES SO IEEE TRANSACTIONS ON ELECTRICAL INSULATION LA English DT Review AB The application of superconductive conductors requires the development of electrical insulation capable of operating for many years at temperatures as low as 4 K and ranging to similar to 100 K for the most recent superconductors. The insulation is subjected to stresses caused by the cryogenic environment, possibly high pressures and radiation, in addition to the electrical stresses associated with service, Experimental results of aging tests for small samples are reported and the operating experiences of superconducting devices in service for about a decade are discussed. RP FORSYTH, EB (reprint author), ASSOCIATED UNIV INC,BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 32 TC 3 Z9 3 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9367 J9 IEEE T ELECTR INSUL PD OCT PY 1993 VL 28 IS 5 BP 845 EP 854 DI 10.1109/14.237745 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA MC766 UT WOS:A1993MC76600010 ER PT J AU ROTEM, D SCHLOSS, GA SEGEV, A AF ROTEM, D SCHLOSS, GA SEGEV, A TI DATA ALLOCATION FOR MULTIDISK DATABASES SO IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING LA English DT Note AB This paper deals with I/O throughput maximization in a single processor/multidisk database system, by means of optimal allocation of entire relations (or other nonfragmented data objects) to disks. We examine the cases in which such allocation is beneficial, and present a mathematical formulation of the problem. This formulation is shown to be flexible enough to accommodate various objectives and.constraints of a typical system design. C1 SAN JOSE STATE UNIV,SCH BUSINESS,DEPT MKT & QUANTITAT STUDIES,SAN JOSE,CA 95192. SUNY STONY BROOK,DEPT COMP SCI,STONY BROOK,NY 11794. UNIV CALIF BERKELEY,WALTER A HAAS SCH BUSINESS,BERKELEY,CA 94720. RP ROTEM, D (reprint author), LAWRENCE BERKELEY LAB,DEPT COMP SCI RES & DEV,DIV INFORMAT & COMP SCI,BERKELEY,CA 94720, USA. NR 18 TC 7 Z9 7 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 1041-4347 J9 IEEE T KNOWL DATA EN JI IEEE Trans. Knowl. Data Eng. PD OCT PY 1993 VL 5 IS 5 BP 882 EP 887 DI 10.1109/69.243516 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA MH081 UT WOS:A1993MH08100012 ER PT J AU RADEKA, V RESCIA, S REHN, LA MANFREDI, PF SPEZIALI, V AF RADEKA, V RESCIA, S REHN, LA MANFREDI, PF SPEZIALI, V TI MONOLITHIC JUNCTION FIELD-EFFECT TRANSISTOR CHARGE PREAMPLIFIER FOR CALORIMETRY AT HIGH-LUMINOSITY HADRON COLLIDERS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article AB The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFET) suggest that a monolithic preamplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described. C1 INTERFET CORP,GARLAND,TX 75042. INFN,SEZ MILANO,I-20133 MILAN,ITALY. UNIV PAVIA,DIPARTIMENTO ELETTR,I-27100 PAVIA,ITALY. RP RADEKA, V (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Rescia, Sergio/D-8604-2011 OI Rescia, Sergio/0000-0003-2411-8903 NR 4 TC 10 Z9 10 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD OCT PY 1993 VL 40 IS 5 BP 1321 EP 1324 DI 10.1109/23.234543 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA LY724 UT WOS:A1993LY72400001 ER PT J AU ANDERS, S ANDERS, A YU, KM YAO, XY BROWN, IG AF ANDERS, S ANDERS, A YU, KM YAO, XY BROWN, IG TI ON THE MACROPARTICLE FLUX FROM VACUUM-ARC CATHODE SPOTS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article ID PLASMA; EVAPORATION; FILMS; GENERATION; PARTICLES; TRANSPORT; EMISSION; DENSITY AB The plasma in vacuum arc cathode spots is always accompanied by a production of metallic macroparticles of size 0.1 - 10 mum. We have studied the macroparticle contamination of vacuum arc deposited thin films generated by a plasma source with an optional axial magnetic field, and have concentrated our attention on the macroparticle flux near the discharge axis. We have varied the arc current, metal species, deposition system geometry and axial magnetic field strength. Distribution functions for macroparticles of Pb, Ag, Cu, Pt, W, and Ni have been determined, normalized to the film thickness deposited or the charge transferred. Application of the axial magnetic field led to a considerable reduction of the normalized macroparticle flux since the plasma was effectively focused by the field whereas the macroparticle production was not influenced. The macroparticle content normalized to the deposited film thickness was reduced to about 20-35% of that without additional magnetic field. RP ANDERS, S (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Yu, Kin Man/J-1399-2012; Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016 OI Yu, Kin Man/0000-0003-1350-9642; Anders, Andre/0000-0002-5313-6505; NR 40 TC 62 Z9 63 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1993 VL 21 IS 5 BP 440 EP 446 DI 10.1109/27.249623 PG 7 WC Physics, Fluids & Plasmas SC Physics GA MQ586 UT WOS:A1993MQ58600010 ER PT J AU BROWN, IG AF BROWN, IG TI VACUUM-ARC ION SOURCES FOR PARTICLE ACCELERATORS AND ION-IMPLANTATION SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article ID CHARGE-STATE DISTRIBUTIONS; BROAD-BEAM; CATHODE EROSION; PLASMA; GENERATION; CARBON; ALLOY AB The vacuum arc is a prolific generator of highly ionized metal plasma. This method of plasma production can be used to advantage to construct a high current metal ion source. We have developed a succession of such metal vapor vacuum arc ion sources at Berkeley, initially for the production of intense beams of uranium ions for injection into the Bevalac heavy ion synchrotron for fundamental nuclear physics research, and also for the production of large area beams of a wide range of metal ion species for carrying out ion implantation for materials surface modification. The beam parameters can be attractive, and the source has provided a valuable addition to the spectrum of ion sources available to the experimenter. We have produced beams from 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with pulsed beam currents in the ampere range. Typically the source is repetitively pulsed with pulse length 250 microseconds and duty cycle of order 1%. We have recently, tested a dc embodiment from which a large area titanium beam with steady-state ion current 600 mA was produced. Separately we have used a 50 cm diameter set of beam formation grids to form a beam of area 1000 cm2 at an energy of 100 keV and a pulsed beam current of approximately 10 A. The source can also be seen as a tool for the study of vacuum arc plasmas, and we have studied vacuum arc ion charge state distributions in this way. Here we describe the general features and performance characteristics of the sources and their use for accelerator injection and ion implantation applications. RP LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NR 77 TC 16 Z9 16 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 EI 1939-9375 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1993 VL 21 IS 5 BP 537 EP 546 DI 10.1109/27.249640 PG 10 WC Physics, Fluids & Plasmas SC Physics GA MQ586 UT WOS:A1993MQ58600027 ER PT J AU JACKSON, PJ ANDERSON, WL DEWITT, JG KE, HYD KUSKE, CR MONCRIEF, RM RAYSON, GD AF JACKSON, PJ ANDERSON, WL DEWITT, JG KE, HYD KUSKE, CR MONCRIEF, RM RAYSON, GD TI ACCUMULATION OF TOXIC METAL-IONS ON CELL-WALLS OF DATURA-INNOXIA SUSPENSION CELL-CULTURES SO IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-PLANT LA English DT Article DE BIOREMEDIATION; DATURA INNOXIA; METAL BINDING; METAL LUMINESCENCE; PLANT CELL WALLS; PLANT SUSPENSION CULTURES ID EU(III) LUMINESCENCE; BINDING-SITES; CADMIUM; ALGAE; ONCOMODULIN AB Rapidly dividing cell suspension cultures derived from Datura innoxia (Mill.) selectively remove certain toxic metal ions from nutrient and waste solutions. Many ions, including necessary micronutrients, bind tightly to different components of the primary cell wall. Cell viability is not required for metal chelation to the extracellular matrix, and biopolymers purified from these cultures can be used to selectively remove metal ions from waste streams. Binding of normally toxic metals to the primary cell wall significantly reduces their toxicity. Chemical and metal luminescence methods that generate information about metal binding and cell-wall components responsible for this are presented. The feasibility of using plant cells and their components for bioremediation is discussed. C1 NEW MEXICO STATE UNIV,DEPT CHEM,LAS CRUCES,NM 88003. RP JACKSON, PJ (reprint author), LOS ALAMOS NATL LAB,DIV LIFE SCI,GENOM & STRUCT BIOL GRP LS2,MAIL STOP M880,LOS ALAMOS,NM 87545, USA. NR 24 TC 7 Z9 7 U1 0 U2 1 PU SOC IN VITRO BIOLOGY PI UPPER MARLBORO PA 9315 LARGO DR W #255, UPPER MARLBORO, MD 20774-4755 SN 1054-5476 J9 IN VITRO CELL DEV-PL JI In Vitro Cell. Dev. Biol.-Plant PD OCT PY 1993 VL 29P IS 4 BP 220 EP 226 PG 7 WC Plant Sciences; Cell Biology; Developmental Biology SC Plant Sciences; Cell Biology; Developmental Biology GA MU411 UT WOS:A1993MU41100012 ER PT J AU WOO, LK MAURYA, MR JACOBSON, RA RINGROSE, SL AF WOO, LK MAURYA, MR JACOBSON, RA RINGROSE, SL TI SYNTHESIS, CHARACTERIZATION, AND X-RAY CRYSTAL-STRUCTURE OF A TRIMETALLIC DIPORPHYRIN COMPLEX SO INORGANICA CHIMICA ACTA LA English DT Note ID (5,10,15,20-TETRAMETHYLPORPHYRINATO)NICKEL(II); MONONUCLEAR; PORPHYRIN AB Treatment of two equivalents of cis-5,15-bis(o-[2-nicotinoy-lamido]phenyl-2,8,12,18-tetraethyl-3,7,13,17-tetramethylporphyrinato nickel(II), [Ni(DPE)-(NH-CO-py)2], with [M(DMSO)4](ClO4)2 in methanol produces trinuclear complexes, [Ni(DPE)-(NH-CO-PY)2]2M(ClO4)2 where M is Pd or Pt. The trinuclear Ni2Pd complex crystallizes from CHCl3 to yield an octasolvate. An X-ray structure determination for [NiO2N8C56H52]2Pd(ClO4)2.8HCCl3 was carried out. Crystal data are as follows: monoclinic, P2(1/n) (No. 14), a = 14.378(7), b = 23.413(6), c = 21.140(6) angstrom, beta = 105.30(3)-degrees, V= 6865(4) angstrom, Z = 2, R = 0.076 and R(w) = 0.082. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP WOO, LK (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 12 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 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD OCT PY 1993 VL 212 IS 1-2 BP 337 EP 340 DI 10.1016/S0020-1693(00)92341-7 PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA ME409 UT WOS:A1993ME40900041 ER PT J AU SUGAMA, T CARCIELLO, NR AF SUGAMA, T CARCIELLO, NR TI POLYPHENYLETHERKETONE AND POLYPHENYLETHERSULFONE ADHESIVES FOR METAL-TO-METAL JOINTS SO INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES LA English DT Article DE POLYPHENYLETHERKETONE; POLYPHENYLETHERSULFONE; STEELS; ADHESION; INTERFACE; BOND STRENGTH ID RAY PHOTOELECTRON-SPECTROSCOPY; POLYMER SURFACES; INTERFACES; PEEK AB Two major factors play an important part in improving adhesive bonding in crystalline polyphenyletherketone (PEK) and amorphous polyphenylethersulfone (PES) polymer-to-metal joint systems: (1) the mechanical strength of reaction product layers formed at polymer/metal interfaces is greater than that of the polymer itself; and (2) the extent of mechanically weak Fe2O3 layers on interfacial metal surfaces, which should be minimized to avoid the undesirable cohesive failure mode through these layers. As a result, the most promising failure mechanism for good bond performance was the mixed cohesive failure modes in which separation occurred in both the polymer and adhesive layers at the polymer/metal interfaces. RP SUGAMA, T (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV ENERGY EFFICIENCY & CONSERVAT,UPTON,NY 11973, USA. NR 14 TC 20 Z9 20 U1 0 U2 4 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0143-7496 J9 INT J ADHES ADHES JI Int. J. Adhes. Adhes. PD OCT PY 1993 VL 13 IS 4 BP 257 EP 266 DI 10.1016/0143-7496(93)90029-9 PG 10 WC Engineering, Chemical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA MF236 UT WOS:A1993MF23600005 ER PT J AU HE, Y LIU, XP LIN, MC MELIUS, CF AF HE, Y LIU, XP LIN, MC MELIUS, CF TI THERMAL-REACTION OF HNCO WITH NO2 AT MODERATE TEMPERATURES SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID NITRIC-OXIDE; CYANURIC ACID; REDUCTION; CHEMISTRY; KINETICS AB The thermal reaction of HNCO with NO2 has been studied in the temperature range of 623 to 773 K by FTIR spectrometry. Major products measured are CO2 and NO with a small amount of N2O. Kinetic modeling of the time resolved concentration profiles of the reactants and products, aided by the thermochemical data of various likely reactive intermediates computed by means of the BAC-MP4 method, allows us to conclude that the reaction is initiated exclusively by a new bimolecular process: (1) NO2 + HNCO --> HN(CO)ONO --> HNNO + CO2 with a rate constant, k1 = 2.5 x 10(12)e-13,100/T cm3/mols. The well-known bimolecular reaction (10) NO2 + NO2 --> 2NO + O2 is the only strong competitive process in this important reactive system throughout the temperature range studied. Kinetic modeling of NO formation and NO2 decay rates gave rise to values of k10 which were in close agreement with literature data. (C) 1993 John Wiley & Sons, Inc. C1 EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322. SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94552. NR 26 TC 23 Z9 24 U1 1 U2 3 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 OCT PY 1993 VL 25 IS 10 BP 845 EP 863 DI 10.1002/kin.550251006 PG 19 WC Chemistry, Physical SC Chemistry GA LZ261 UT WOS:A1993LZ26100005 ER PT J AU LYCZKOWSKI, RW DOMANUS, HM BOTTONI, M SHA, WT AF LYCZKOWSKI, RW DOMANUS, HM BOTTONI, M SHA, WT TI ANALYSIS OF CRITICAL AND SUBCRITICAL FLOW BOILING SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article AB Low pressure flow boiling has been computer-simulated by means of the Homogeneous Equilibrium Mixture (HEM) and algebraic slip model of two-phase flow using a transient computer code. Numerical difficulties were experienced when the two-phase velocity exceeded the HEM model's speed of sound at the inception of boiling during the solution procedure. An apparent anomaly experienced was the calculation of pressure undershoots ('kinks') across a two-phase boiling region surrounded by single-phase subcooled liquid. It is clearly shown that,the HEM model's speed of sound is a critical state for the evaluation of the pressure gradient. When this speed of sound is not exceeded at the inception of boiling, numerically stable and accurate results are computed. Some means of resolving these apparently fundamental and generic problems are suggested. C1 ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439. RP LYCZKOWSKI, RW (reprint author), ARGONNE NATL LAB,DIV ENERGY SYST,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 17 TC 2 Z9 2 U1 0 U2 3 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 OCT PY 1993 VL 36 IS 15 BP 3813 EP 3822 DI 10.1016/0017-9310(93)90061-A PG 10 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA LX918 UT WOS:A1993LX91800017 ER PT J AU PASAMEHMETOGLU, KO CHAPPIDI, PR UNAL, C NELSON, RA AF PASAMEHMETOGLU, KO CHAPPIDI, PR UNAL, C NELSON, RA TI SATURATED POOL NUCLEATE BOILING MECHANISMS AT HIGH HEAT FLUXES SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID MACROLAYER; EVAPORATION; MODEL; FLOW AB A new model has been developed where the coupled transient two-dimensional conduction equation is solved for the heater and the liquid macrolayer, while allowing for the time-wise thinning of the macrolayer. The major conclusions are: (1) dominant evaporation occurs at the liquid-vapor-solid contact point (triple point) and is required to match boiling curve behavior quantitatively; (2) evaporation at the stem interface and bubble-macrolayer interface is negligible (except near critical heat flux); and (3) the results are sensitive to closure relationships, especially to the active site-density correlation. RP PASAMEHMETOGLU, KO (reprint author), LOS ALAMOS NATL LAB, DIV NUCL TECHNOL & ENGN, ENGN & SAFETY ANAL GRP, LOS ALAMOS, NM 87545 USA. NR 24 TC 20 Z9 20 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 EI 1879-2189 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 1993 VL 36 IS 15 BP 3859 EP 3868 DI 10.1016/0017-9310(93)90066-F PG 10 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA LX918 UT WOS:A1993LX91800022 ER PT J AU DEAN, DJ BOTTCHER, C STRAYER, MR WELLS, JC AF DEAN, DJ BOTTCHER, C STRAYER, MR WELLS, JC TI PARALLEL IMPLEMENTATION OF 3+1-DIMENSIONAL RELATIVISTIC HYDRODYNAMICS SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article DE RELATIVISTIC HYDRODYNAMICS; BASIS-SPLINE COLLOCATION METHOD ID FLUX-CORRECTED TRANSPORT; HEAVY-ION COLLISIONS; ALGORITHM; LATTICE AB We discuss the parallel implementation of 3+1-dimensional relativistic hydrodynamics. The discretization of these equations is performed with a basis-spline collocation method. An iterative procedure for the time evolution will also be discussed. Approximately 60% of the computational effort is spent in performing vector-matrix multiplications that may easily be vectorized. Furthermore, for large lattices, these operations may be spread across the nodes of a parallel machine. We show how to accomplish this partitioning for the hydrodynamic evolution equations. A double-ring, message-passing algorithm is shown to enhance overall code performance when compared to a single ring on iPSC/i860 architectures. Overall code performance is discussed, and an application to relativistic nuclear collision physics is presented. C1 OAK RIDGE NATL LAB, DIV PHYS, CTR COMPUTAT INTENS FIS, OAK RIDGE, TN 37831 USA. VANDERBILT UNIV, DEPT PHYS & ASTRON, NASHVILLE, TN 37235 USA. RP CALTECH, KELLOGG RADIAT LAB, PASADENA, CA 91125 USA. RI Wells, Jack/D-3675-2016 OI Wells, Jack/0000-0002-5083-3030 NR 22 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0129-1831 EI 1793-6586 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD OCT PY 1993 VL 4 IS 5 BP 1023 EP 1040 DI 10.1142/S0129183193000793 PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ME121 UT WOS:A1993ME12100010 ER PT J AU SANDERS, CL LAUHALA, KE MCDONALD, KE AF SANDERS, CL LAUHALA, KE MCDONALD, KE TI LIFE-SPAN STUDIES IN RATS EXPOSED TO (PUO2)-PU-239 AEROSOL .3. SURVIVAL AND LUNG-TUMORS SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID INHALED (PUO2)-PU-239; INHALATION CARCINOGENESIS; PLUTONIUM; TUMORS; AUTORADIOGRAPHY; PUO2(PU-239); IRRADIATION; AGGREGATION; INDUCTION; EXPOSURES AB Female, young adult, Wistar rat were given a single inhalation exposure to a submicron sized aerosol of high-fired (PuO2)-Pu-239 and observed during their lifespan for primary lung tumours. Rats were distributed among sham-control (n = 1052) and exposed (n = 2105) groups. Survival was significantly reduced only in rat with lung doses > 30 Gy. A total of 99 primary lung tumours were found, of which 92% were malignant and 80% were carcinomas. Of malignant lung tumours, 49 were squamous cell carcinoma, 23 adenocarcinoma, nine hemangiosarcoma, seven adenosquamous carcinoma, and three fibrosarcoma. One adenocarcinoma was found in controls and only four adenomas were seen in the exposed rat at lung doses < 1.5 Gy. The lowest doses at which lung tumours appeared in exposed rats were 1.5 Gy for squamous cell carcinoma, 3.1 Gy for adenocarcinoma. 4.1 Gy for hemangiosarcoma, and about 9 Gy for adenosquamous carcinoma and fibrosarcoma. Pulmonary squamous metaplasia was not seen in controls and was first seen in exposed rats only at lung doses > 1 Gy. Primary lung tumours were the presumed cause of death (fatal) in 60% of rats with malignant lung tumours; causes of death were equally distributed among all tumour types and doses. The incidence of all lung tumours was 0.095% in control rats, 0.21% in 1877 rats with lung doses < 1 Gy, and 41% in 228 rats with doses > 1 Gy. Lung tumour incidence increased in a linear manner from 6.9% at 2.3 Gy to an incidence of 64-88% at 16-44 Gy. Absolute malignant lung tumour risk averaged 270 lung tumours per 10(4) rat-Gy above a lung dose of 1 Gy. All types of malignant lung tumours induced by inhaled (PuO2)-Pu-239 exhibited a threshold at a lung dose > 1 Gy. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP SANDERS, CL (reprint author), WASHINGTON STATE UNIV TRI CITIES, CTR HLTH RES & EDUC, 100 SPROUT RD, RICHLAND, WA 99352 USA. NR 52 TC 44 Z9 45 U1 1 U2 3 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 OCT PY 1993 VL 64 IS 4 BP 417 EP 430 DI 10.1080/09553009314551601 PG 14 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 MD008 UT WOS:A1993MD00800008 PM 7901303 ER PT J AU PONCY, JL RATEAU, G BURGADA, R BAILLY, T LEROUX, Y RAYMOND, KN DURBIN, PW MASSE, R AF PONCY, JL RATEAU, G BURGADA, R BAILLY, T LEROUX, Y RAYMOND, KN DURBIN, PW MASSE, R TI EFFICACY OF 3,4,3-LIHOPO FOR REDUCING THE RETENTION OF PU-238 IN RAT AFTER INHALATION OF THE TRIBUTYL-PHOSPHATE COMPLEX SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID PLUTONIUM TRIBUTYLPHOSPHATE; BABOONS; LIGANDS; DTPA; DECORPORATION; EXCRETION; AMERICIUM; THERAPY; PU AB The efficacy of 3,4,3-LIHOPO, a siderophore analogue, has been tested for removing Pu-238 from rat after inhalation of plutonium as the tri-N-butylphosphate (TBP) complex. The amounts of Pu retained in the lung of untreated rat, 7 days after exposure ranged from 0.86 to 37 kBq. The results have been compared with DTPA, the current therapy of choice for man. The ligand 3,4,3-LIHOPO was more effective than DTPA for removing Pu from the body when repeated treatment began 1 h after inhalation. This observation was independent of the mass of Pu deposited in the lungs. The efficacy of 3,4,3-LIHOPO was mainly due to the decrease of Pu retention in lung, 1.5 times less than after DTPA administration; in liver and skeleton, retention was about four times less. Seven days after internal contamination, < 10% of the activity was found in organs other than lung when rat was treated with 3,4,3-LIHOPO. As this ligand showed an apparent lack of irreversible toxicity, it is likely to be of interest in the development of new decorporation treatments after inhalation of Pu as a TBP complex. C1 UNIV PARIS 06,CHIM ORGANOELEMENTS LAB,F-75252 PARIS,FRANCE. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV PARIS NORD,CHIM STRUCT BIOMOLEC LAB,F-39012 BOBIGNY,FRANCE. RP PONCY, JL (reprint author), CEA,DSV DPTE LRT,BP 12,F-91680 BRUYERES CHATEL,FRANCE. NR 19 TC 12 Z9 12 U1 1 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 OCT PY 1993 VL 64 IS 4 BP 431 EP 436 DI 10.1080/09553009314551611 PG 6 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 MD008 UT WOS:A1993MD00800009 PM 7901304 ER PT J AU QUICK, TM AF QUICK, TM TI EDM AND THE RESULTING HYDROGEN EMBRITTLEMENT OF MARAGING-STEEL SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article AB The use of electrical discharge machining (EDM), or spark erosion as it is sometimes called, introduces hydrogen into maraging steel 250 such that brittle fracture surfaces result from embrittlement accelerated by slow-strain-rate tensile tests. Brittle fracture features indicate potential premature failure due to hydrogen embrittlement. Experimental control was provided by test specimens machined by abrasive waterjet, a machining technique that does not evolve hydrogen as a part of the machining process. Hydrogen concentration measurements indicate the hydrogen concentration of specimens fabricated by EDM is approximately 0.5 ppm, while that of specimens machined by abrasive waterjet is approximately 0.1 ppm. On the basis of constant-load tests, the time to failure of test specimens machined by EDM and loaded to 50% of the yield strength is estimated to be a minimum of 30 years. RP QUICK, TM (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550, USA. NR 10 TC 1 Z9 1 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD OCT PY 1993 VL 45 IS 10 BP 52 EP 55 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA MB381 UT WOS:A1993MB38100009 ER PT J AU JERVIS, TR HIRVONEN, JP NASTASI, M AF JERVIS, TR HIRVONEN, JP NASTASI, M TI LASER-SURFACE PROCESSING IN THE ULTRA-VIOLET FOR TRIBOLOGICAL APPLICATIONS IN METALS AND CERAMICS SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID AISI-304 STAINLESS-STEEL; MECHANICAL-PROPERTIES; MULTILAYERED FILMS; TI; MICROSTRUCTURE; ALLOYS; LAYERS AB Surface modification using ion beams and infrared laser light has proven to be of benefit to tribological systems in a number of applications. We will describe the use of excimer laser light in the ultraviolet for surface alloying of metal and ceramic systems with excellent tribological results. Specifically, we have observed reduced friction in dry sliding conditions and a change in wear processes resulting in greatly reduced surface damage. We interpret these results in light of changes in the microstructural, mechanical, and tribochemical properties of the surface C1 TECH RES CTR FINLAND,ESPOO,FINLAND. LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP JERVIS, TR (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD OCT PY 1993 VL 25 IS 1 BP 4 EP 10 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA MW920 UT WOS:A1993MW92000001 ER PT J AU JULIEN, S CHORNET, E OVEREND, RP AF JULIEN, S CHORNET, E OVEREND, RP TI INFLUENCE OF ACID PRETREATMENT (H2SO4,HCL,HNO3) ON REACTION SELECTIVITY IN THE VACUUM PYROLYSIS OF CELLULOSE SO JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS LA English DT Article; Proceedings Paper CT PYROLYSIS 92 - 10TH INTERNATIONAL CONF ON FUNDAMENTAL ASPECTS, PROCESSES AND APPLICATIONS OF PHYROLYSIS CY SEP 28-20, 1992 CL HAMBURG, GERMANY DE CELLULOSE; FT-IR; INORGANIC IONS; LEVOGLUCOSAN; PYROLYSIS; VACUUM PYROLYSIS ID PRODUCT DISTRIBUTION; FLASH PYROLYSIS; HEATING RATE; BIOMASS; YIELD AB Vacuum pyrolysis of acid-impregnated (H2SO4, HCl, HNO3) purified cellulose was carried out at a heating rate of 10-degrees-C min-1 and a constant final temperature (380-degrees-C). The average pressure was 130 Pa in the retort. The objective was to study the influence of inorganic ion content on the thermal decomposition of cellulose. The pH of the acid solutions (H2SO4, HCl, HNO3) used to impregnate the cellulose was adjusted (to 0.5, 1.0, 2.0, 4.0, or 7.0) to introduce 1-0.01 atoms of acid per 100 mol of anhydroglucose units of cellulose. The substrates and solid residues were characterized by X-ray scattering, elemental analysis, TGA and FT-IR. The qualitative analysis of the inorganic ion content of pretreated cellulose by X-ray scattering showed, in the case of H2SO4 and HCl pretreatments, that inorganic ions (SO42- and Cl-) were incorporated into the cellulose. Thermograms of pretreated cellulose showed that high contents of inorganic ions (SO42- and Cl-) accelerated the beginning of the weight loss and increased the char yield, whereas the weight loss profile for HNO3 pretreated celluloses was nearly the same at different pH values. The FT-IR spectra of H2SO4 and HCl pretreated celluloses showed that the bands corresponding to ring stretching increased at low pH (0.5), thus indicating that the pyranose ring was altered, No change was observed with the HNO3 pretreatment. Overall, the FT-IR information showed that the residual solids had an olefinic and carbonyl character. The carbonyl character of the residual solid was the same with the H2SO4 and HCl pretreatments at low pH (0.5, 1.0) and with all the HNO3 pretreatments. The anions (SO42- and Cl incorporated by the acid pretreatment into the cellulose induced the formation of high yields of char and water and low yields of pyrolytic oil. The inorganic ions favored the formation of hydroxyacetaldehyde, acetic acid and formic acid at the expense of levoglucosan. We observed no significant change in product yields for cellulose pretreated with HNO3. C1 UNIV SHERBROOKE,DEPT CHEM ENGN,SHERBROOKE J1K 2R1,QUEBEC,CANADA. NATL RENEWABLE ENERGY INST,GOLDEN,CO 80401. OI Overend, Ralph/0000-0002-5442-0890 NR 30 TC 49 Z9 50 U1 3 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-2370 J9 J ANAL APPL PYROL JI J. Anal. Appl. Pyrolysis PD OCT PY 1993 VL 27 IS 1 BP 25 EP 43 DI 10.1016/0165-2370(93)80020-Z PG 19 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA MA348 UT WOS:A1993MA34800003 ER PT J AU MARLER, B DEROCHE, C GIES, H FYFE, CA GRONDEY, H KOKOTAILO, GT FENG, Y ERNST, S WEITKAMP, J COX, DE AF MARLER, B DEROCHE, C GIES, H FYFE, CA GRONDEY, H KOKOTAILO, GT FENG, Y ERNST, S WEITKAMP, J COX, DE TI THE STRUCTURE OF ZEOLITE ZSM-23 (MTT) REFINED FROM SYNCHROTRON X-RAY-POWDER DATA SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB The structure of zeolite ZSM-23 (structure-type code MTT) loaded with NH4F [a(o) = 11.129 (1), b(o) = 5.025 (1) and c(o) = 21.519 (1) angstrom and beta = 89.85 (4)-degrees] was refined from high-resolution synchrotron X-ray powder data. The Rietveld refinement converged in space group P12(1)1 (No. 4) to R(F) = 0.090 and R(wp) = 0.085, confirming the proposed model of the silicate framework. The use of complementary methods (synchrotron X-ray powder diffraction, Si-29 magic-angle-spinning, nuclear-magnetic-resonance spectroscopy, and distance and angle least-squares refinements) was essential for the determination of the true space-group symmetry, a prerequisite for the successful Rietveld structure refinement. C1 UBC,DEPT CHEM,VANCOUVER,BC,CANADA. UNIV STUTTGART,INST CHEM TECHNOL I,W-7000 STUTTGART 80,GERMANY. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP MARLER, B (reprint author), RUHR UNIV BOCHUM,INST MINERAL,W-4630 BOCHUM,GERMANY. RI Gies, Hermann/B-6637-2009 OI Gies, Hermann/0000-0002-2110-2458 NR 9 TC 25 Z9 26 U1 1 U2 8 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT 1 PY 1993 VL 26 BP 636 EP 644 DI 10.1107/S0021889893002006 PN 5 PG 9 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA ME347 UT WOS:A1993ME34700003 ER PT J AU DARKEN, LS JELLISON, GE AF DARKEN, LS JELLISON, GE TI RESOLUTION DEGRADATION OF COAXIAL P-TYPE GERMANIUM DETECTORS DUE TO HOLE TRAPPING BY POINT-DEFECTS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ACCEPTORS; CAPTURE AB A quantitative relationship has been experimentally determined correlation the resolution degradation of p-type coaxial high-purity germanium detectors to the concentration of residual hole-trapping point defects. Detector diameters ranged from 48 to 65 mm, and the average electric-field strength was 1500 V/cm. The concept of a ''standard level'' is proposed, which originates in the similar capture kinetics of many commonly observed residual acceptors in high-purity germanium. A method for calculating the electric-field dependence of hole capture is presented and used to compare the data reported here with published modeling results parameterized by the mean-free-drift length. Good general agreement is found. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP DARKEN, LS (reprint author), OXFORD INSTRUMENTS INC,601 OAK RIDGE TURNPIKE,OAK RIDGE,TN 37831, USA. NR 10 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1993 VL 74 IS 7 BP 4557 EP 4560 DI 10.1063/1.354374 PG 4 WC Physics, Applied SC Physics GA MB177 UT WOS:A1993MB17700039 ER PT J AU LUSH, GB MELLOCH, MR LUNDSTROM, MS MACMILLAN, HF ASHER, S AF LUSH, GB MELLOCH, MR LUNDSTROM, MS MACMILLAN, HF ASHER, S TI CONCENTRATION-DEPENDENT OPTICAL-ABSORPTION COEFFICIENT IN N-TYPE GAAS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MINORITY-CARRIER LIFETIME; INTERNAL QUANTUM EFFICIENCY; HEAVILY DOPED GAAS; P-TYPE GAAS; DOUBLE HETEROSTRUCTURES; REFRACTIVE-INDEX; EPITAXIAL GAAS AB The doping-dependent, near-band-edge optical-absorption coefficient alpha(hv) was deduced from optical transmission measurements in n-type GaAs thin films. The selenium-doped films were grown by metalorganic chemical-vapor deposition and doped to produce room-temperature electron concentrations from 1.3 X 10(17) to 3.8 X 10(18) cm-3. The transmission measurements covered photon energies between 1.35 and 1.7 eV and were performed on double heterostructures with the substrate removed by selective etching. The results show good qualitative agreement with previous studies and good quantitative agreement, except for the heavily doped samples. For n0 = 3.8 X 10(18) cm-3, alpha(1.42 eV) is approximately four times that reported by previous workers. Secondary-ion-mass spectrometry measurements on films grown under differing conditions demonstrate that alpha(hv) is sensitive to electrically inactive dopants and supports the hypothesis that precipitates or compensation influenced previous measurements. These comprehensive results on high-quality, uncompensated material should prove useful for fundamental studies of optical transitions in n-type GaAs as well as for modeling optoelectronic devices. C1 VARIAN RES CTR,PALO ALTO,CA 94303. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP LUSH, GB (reprint author), PURDUE UNIV,DEPT ELECT ENGN,W LAFAYETTE,IN 47907, USA. NR 35 TC 8 Z9 8 U1 3 U2 6 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 OCT 1 PY 1993 VL 74 IS 7 BP 4694 EP 4702 DI 10.1063/1.354336 PG 9 WC Physics, Applied SC Physics GA MB177 UT WOS:A1993MB17700058 ER PT J AU WOS, L AF WOS, L TI THE PROBLEM OF REASONING BY CASE ANALYSIS SO JOURNAL OF AUTOMATED REASONING LA English DT Article DE AUTOMATED REASONING; CASE ANALYSIS; UNSOLVED RESEARCH PROBLEM AB This article is the twenty-ninth of a series of articles discussing various open research problems in automated reasoning. The problem proposed for research asks one to find criteria that an automated reasoning program can apply to decide when to conduct a case analysis argument and to decide which cases are appropriate. When the choice of employing a case analysis argument is wise and the cases are well chosen, the likelihood that the reasoning program - or, for that matter, a person - will find an answer to the given question is sharply increased. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NR 5 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-7433 J9 J AUTOM REASONING JI J. Autom. Reasoning PD OCT PY 1993 VL 11 IS 2 BP 289 EP 291 DI 10.1007/BF00881909 PG 3 WC Computer Science, Artificial Intelligence SC Computer Science GA MX351 UT WOS:A1993MX35100006 ER PT J AU MA, D COOK, DN ALBERTI, M PON, NG NIKAIDO, H HEARST, JE AF MA, D COOK, DN ALBERTI, M PON, NG NIKAIDO, H HEARST, JE TI MOLECULAR-CLONING AND CHARACTERIZATION OF ACRA AND ACRE GENES OF ESCHERICHIA-COLI SO JOURNAL OF BACTERIOLOGY LA English DT Article ID DNA TOPOISOMERASE-I; NUCLEOTIDE-SEQUENCE; OUTER MEMBRANES; GYRASE GENES; PHYSICAL MAP; MUTATIONS; TRANSCRIPTION; EXPRESSION; MUTANTS; K-12 AB The DNA fragment containing the acrA locus of the Escherichia coli chromosome has been cloned by using a complementation test. The nucleotide sequence indicates the presence of two open reading frames (ORFs). Sequence analysis suggests that the first ORF encodes a 397-residue lipoprotein with a 24-amino-acid signal peptide at its N terminus. One inactive allele of acrA from strain N43 was shown to contain an IS2 element inserted into this ORF. Therefore, this ORF was designated acrA. The second downstream ORF is predicted to encode a transmembrane protein of 1,049 amino acids and is named acrE. Genes acrA and acrE are probably located on the same operon, and both of their products are likely to affect drug susceptibilities observed in wild-type cells. The cellular localizations of these polypeptides have been analyzed by making acrA=TnphoA and acrE=TnphoA fusion proteins. Interestingly, AcrA and AcrE share 65 and 77% amino acid identity with two other E. coli polypeptides, EnvC and EnvD, respectively. Drug susceptibilities in one acrA mutant (N43) and one envCD mutant (PM61) have been determined and compared. Finally, the possible functions of these proteins are discussed. C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV STRUCT BIOL,BERKELEY,CA 94720. RP MA, D (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. FU NIGMS NIH HHS [R1 GM 41911A-03-NF-03/92] NR 46 TC 302 Z9 311 U1 3 U2 9 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 OCT PY 1993 VL 175 IS 19 BP 6299 EP 6313 PG 15 WC Microbiology SC Microbiology GA MA074 UT WOS:A1993MA07400030 PM 8407802 ER PT J AU GUPTA, G ANANTHARAMAIAH, GM SCOTT, DR ELDRIDGE, JH MYERS, G AF GUPTA, G ANANTHARAMAIAH, GM SCOTT, DR ELDRIDGE, JH MYERS, G TI SOLUTION STRUCTURE OF THE V3 LOOP OF A THAILAND HIV ISOLATE SO JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; PRINCIPAL NEUTRALIZING DETERMINANT; ENVELOPE GLYCOPROTEIN GP120; ANTIBODIES; PROTEINS; PEPTIDES; DOMAIN; BONDS AB The principal neutralizing determinant (PND) of human immunodeficiency virus (HIV) is located inside the third variable loop (designated the V3 loop) of the envelope glycoprotein gp120. The V3 loop is typically 35 amino-acids long, and the Ist and the 35th residues in the loop are invariant cystines involved in a disulfide-bridge. Although PNDs from different HIV isolates contain a conserved GPG-sequence, the amino acids flanking the conserved sequence show hypervariability among HIV isolates; the GPG and the two flanking regions are collectively referred to as the GPG-crest or the PND. The amino acid sequence variability in the GPG-crest gives rise to different antigenic specificities for different PNDs from different HN isolates. By combining two-dimensional nuclear magnetic resonance (2D NMR) and molecular modeling techniques, we have developed a method to study(l) the global tertiary fold of the V3 loops of HIV and (2) the local structure of the PND at the tip of the V3 loop. In this article, we report the results of our structural studies on the V3 loop of a Thailand HIV isolate. The sequential assignment is made by combining DQF-COSY, TOCSY, and NOESY/ROESY experiments. Various intra- and inter-residue inter-proton distances are estimated by full-matrix analyses of the NOESY data at 100 and 400 ms of mixing times and of the ROESY data at 60 and 200 ms of mixing times. 100 inter-residue distances are used as structural constraints in a simulated annealing procedure to derive energetically stable structures. Two functional motifs in the V3 loop, i.e., the glycosylation site and the GPG-crest, form defined structures: a turn is located at the glycosylation site, and the GPG-crest forms a protruding domain with a type-II GPGQ turn. The other regions of the V3 loop are rather flexible - especially the C-terminal DIRKAYC-stretch. These flexible regions of the V3 loop lead to conformational flexure of the entire V3 loop without altering the local structures of the glycosylation site or the GPG-crest. However, the ROESY experiments revealed no slow exchange among different V3 loop conformations, and therefore the flexible conformations are in fast exchange within the NMR time scale. The extent of this conformational flexibility is also discussed. C1 UNIV ALABAMA,MED CTR,DEPT MED,BIRMINGHAM,AL 35294. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,NMR INSTRUMENT FACIL,AMES,IA 50011. UNIV ALABAMA,MED CTR,DEPT MED & MICROBIOL,BIRMINGHAM,AL 35294. RP GUPTA, G (reprint author), LOS ALAMOS NATL LAB,THEORET BIOL & BIOPHYS GRP,T-10,MS K710,LOS ALAMOS,NM 87545, USA. FU NIAID NIH HHS [R01 AI32891-01A2] NR 25 TC 47 Z9 50 U1 0 U2 2 PU ADENINE PRESS INC PI GUILDERLAND PA PO BOX 355/340, GUILDERLAND, NY 12084 SN 0739-1102 J9 J BIOMOL STRUCT DYN JI J. Biomol. Struct. Dyn. PD OCT PY 1993 VL 11 IS 2 BP 345 EP & PG 0 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA MF289 UT WOS:A1993MF28900010 PM 8286061 ER PT J AU RESCIGNO, TN LENGSFIELD, BH OREL, AE AF RESCIGNO, TN LENGSFIELD, BH OREL, AE TI INTERCHANNEL COUPLING AND GROUND-STATE CORRELATION-EFFECTS IN THE PHOTOIONIZATION OF CO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID KOHN VARIATIONAL METHOD; CROSS-SECTIONS; PHOTO-IONIZATION; ASYMMETRY PARAMETERS; MOLECULAR NITROGEN; CARBON-MONOXIDE; ELECTRON-IMPACT; WAVE-FUNCTIONS; EXPRESSIONS; SCATTERING AB We describe a general procedure for applying the complex Kohn variational method to the calculation of molecular photoionization cross sections and asymmetry parameters. In this initial application of the method, we examine the effects of interchannel coupling and ground state correlation on the X2SIGMA+(5sigma-1), A2Pi(1pi-1), and B2SIGMA+ (4sigma-1) partial photoionization cross sections and asymmetry parameters for the CO molecule. We find that the dominant effect of interchannel coupling is to remove a spurious pi-->pi* resonance feature from the continuum that appears at the frozen-core Hartree-Fock level. We also find that it appears to be important to combine the effects of final channel coupling with a correlated initial target state to achieve quantitatively correct cross sections. C1 UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94550. RP RESCIGNO, TN (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 26 TC 27 Z9 27 U1 1 U2 3 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 OCT 1 PY 1993 VL 99 IS 7 BP 5097 EP 5103 DI 10.1063/1.466010 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LY603 UT WOS:A1993LY60300023 ER PT J AU SUN, JQ RUEDENBERG, K AF SUN, JQ RUEDENBERG, K TI QUADRATIC STEEPEST DESCENT ON POTENTIAL-ENERGY SURFACES .1. BASIC FORMALISM AND QUANTITATIVE ASSESSMENT SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTRINSIC REACTION COORDINATE; REACTION PATHS; ALGORITHMS; DYNAMICS AB A novel second-order algorithm is formulated for determining steepest-descent lines on potential energy surfaces. The reaction path is deduced from successive exact steepest-descent lines of local quadratic approximations to the surface. At each step, a distinction is made between three points: the center for the local quadratic Taylor expansion of the surface, the junction of the two adjacent local steepest-descent line approximations, and the predicted approximation to the true steepest-descent line. This flexibility returns a more efficient yield from the calculated information and increases the accuracy of the local quadratic approximations by almost an order of magnitude. In addition, the step size is varied with the curvature and, if desired, can be readjusted by a trust region assessment. Applications to the Gonzalez-Schlegel and the Muller-Brown surfaces show the method to compare favorably with existing methods. Several measures are given for assessing the accuracy achieved without knowledge of the exact steepest-descent line. The optimal evaluation of the predicted gradient and curvature for dynamical applications is discussed. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP SUN, JQ (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 16 TC 63 Z9 63 U1 0 U2 8 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 OCT 1 PY 1993 VL 99 IS 7 BP 5257 EP 5268 DI 10.1063/1.465994 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LY603 UT WOS:A1993LY60300040 ER PT J AU SUN, JQ RUEDENBERG, K AF SUN, JQ RUEDENBERG, K TI QUADRATIC STEEPEST DESCENT ON POTENTIAL-ENERGY SURFACES .2. REACTION-PATH FOLLOWING WITHOUT ANALYTIC HESSIANS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ALGORITHMS AB A second order method is developed for determining steepest descent lines of potential energy surfaces by following steepest curves of successive local quadratic surface approximations. The basic principle is similar to that of a previously developed method where, however, the availability of analytically calculated exact Hessians was assumed wherever needed. By contrast, only the analytically calculated exact values of the energy and its gradient are used here and this difference entails marked changes in strategy. Applications to the Gonzalez-Schlegel and the Muller-Brown surfaces show that the method compares favorably with existing methods. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP SUN, JQ (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 8 TC 60 Z9 60 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 OCT 1 PY 1993 VL 99 IS 7 BP 5269 EP 5275 DI 10.1063/1.465995 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LY603 UT WOS:A1993LY60300041 ER PT J AU SUN, JQ RUEDENBERG, K ATCHITY, GJ AF SUN, JQ RUEDENBERG, K ATCHITY, GJ TI QUADRATIC STEEPEST DESCENT ON POTENTIAL-ENERGY SURFACES .3. MINIMA SEEKING ALONG STEEPEST DESCENT LINES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID OPTIMIZATION; GEOMETRIES; PATHS AB A simplified quadratic steepest descent method, based on the availability of energies and gradients, is formulated for use in minimum searching. It requires only a fraction of the computational effort needed for the previously developed accurate steepest descent procedures and, typically, involves less work than standard quasi-Newton minimum searches. At the same time, it follows the true steepest descent curves reasonably closely and reaches the closest minima. This is in contrast to quasi-Newton procedures which cannot be relied upon to do so. The performance is documented by applications to a variety of searches on the Muller-Brown surface. C1 IOWA STATE UNIV SCI & TECHNOL, DEPT CHEM, AMES, IA 50011 USA. RP US DOE, AMES LAB, AMES, IA 50011 USA. NR 26 TC 27 Z9 27 U1 3 U2 6 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 OCT 1 PY 1993 VL 99 IS 7 BP 5276 EP 5280 DI 10.1063/1.465996 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LY603 UT WOS:A1993LY60300042 ER PT J AU MELENKEVITZ, J CURRO, JG SCHWEIZER, KS AF MELENKEVITZ, J CURRO, JG SCHWEIZER, KS TI VARIATIONAL APPROACH TO THE CONFORMATION OF FLEXIBLE POLYMERS IN SOLUTION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTEGRAL-EQUATION THEORY; EQUILIBRIUM-THEORY; MOLECULAR LIQUIDS; EXCESS ELECTRONS; COPOLYMER MELTS; SIMPLE FLUIDS; CHAIN; SOLVENT; BLENDS; TRANSITION AB Approximate solutions to the self-consistent reference interaction-site model (RISM) integral equation theory of polymer liquids are employed to study the conformational properties of flexible polymers as a function of density and chain length. The nonlinear nature of the expression describing the medium-induced potential between two sites along the polymer chain necessitates the use of approximate methods to determine the intrachain pair-correlation function consistent with the interchain packing. In the limiting case where the polymer segment hard-core diameter approaches zero and the number of interaction sites comprising the chain goes to infinity, with the segment volume fraction held fixed, the intrachain pair correlation function is determined through a Feynman variational procedure for the effective free energy of a single chain in solution. The screening of the excluded volume interactions and the corresponding reduction of the polymer dimensions as a function of both polymer density and chain length is systematically studied with the results being in good agreement with scaling predictions. In addition, the variational method is successfully extended to chains having finite hard-core diameters, with the predictions of the theory comparing favorably with existing theories for polymer solutions based on field theoretic approaches. C1 UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. RP MELENKEVITZ, J (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 47 TC 68 Z9 68 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 OCT 1 PY 1993 VL 99 IS 7 BP 5571 EP 5580 DI 10.1063/1.465949 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LY603 UT WOS:A1993LY60300075 ER PT J AU HERDT, GC SWANSON, LW AF HERDT, GC SWANSON, LW TI VAN-DER-WAALS FORCES ON THIN LIQUID-FILMS IN CAPILLARY TUBES SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article C1 HEAT TRANSFER RES INC,COLL STN,TX 77840. RP HERDT, GC (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 23 TC 1 Z9 1 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 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD OCT 1 PY 1993 VL 160 IS 1 BP 72 EP 78 DI 10.1006/jcis.1993.1369 PG 7 WC Chemistry, Physical SC Chemistry GA LY247 UT WOS:A1993LY24700009 ER PT J AU BIEFELD, RM BAUCOM, KC KURTZ, SR FOLLSTAEDT, DM AF BIEFELD, RM BAUCOM, KC KURTZ, SR FOLLSTAEDT, DM TI THE GROWTH OF INP1-XSBX BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID STRAINED-LAYER SUPERLATTICES; PHASE EPITAXIAL-GROWTH; ALLOYS AB InP1-xSbx was grown by metalorganic chemical vapor deposition under a variety of conditions. The V/III vapor phase ratio was varied from 327 to 12 over a temperature range of 450-525-degrees-C, at pressures of 77 to 660 Torr and growth rates of 0.30 to 2.0 mum/h. For some samples, the V/III vapor phase ratio was optimized for InP1-xSbx lattice matched to InAs to give smooth morphologies and lattice matching with a minimized variation of composition versus changes in the TMSb/(TMSb + PH3) ratio. Examination by transmission electron microscopy indicates that the materials are not single phase, but have undergone a spinodal decomposition, which is consistent with thermodynamic calculations. When our specimen compositions are corrected for strain relaxation, the infrared photoluminescence measurements indicate a lower energy photoluminescence peak for these materials than had been previously reported in the literature. Infrared absorption and photoconductivity measurements indicate no sharp band edge as would be expected for a direct gap semiconductor. The observed broad spectra are consistent with alloy decomposition. RP BIEFELD, RM (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 13 TC 26 Z9 26 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD OCT PY 1993 VL 133 IS 1-2 BP 38 EP 46 DI 10.1016/0022-0248(93)90101-2 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA MB741 UT WOS:A1993MB74100005 ER PT J AU BENNAHMIAS, M RADOUSKY, HB GOODWIN, TJ SHELTON, RN AF BENNAHMIAS, M RADOUSKY, HB GOODWIN, TJ SHELTON, RN TI SUPERCONDUCTIVITY AND MAGNETISM IN NIOBIUM DOPED YBA2CU3O7 RELATED HIGH T(C) CERAMICS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE 123 RELATED CERAMICS; CERIUM; CRITICAL CURRENT DENSITY; DC IRREVERSIBILITY; LOWER CRITICAL FIELD; MAGNETIC ORDERING; MAGNETIC SUSCEPTIBILITY; NIOBIUM; PRASEODYMIUM ID CUPRATE; SAMPLES; ORDER; PR AB Magnetic characterization has been performed on the members of the cuprate-niobate RBa2Cu2NbO8 (R = Pr, Nd, and La) series and R1.5Ce0.5Sr2Cu2 NbO10 (R = Pr, Eu, Nd, and Sm) series. The PrBCNO samples show a signature in the magnetization of a magnetic ordering at 12K. The PrCSCNO sample is nonsuperconducting and shows two distinct orderings at 17K and 53K. No such magnetic phase transition is observed down to 2K in the Nd and La based RBCNO materials or the Nd, Sm, and Eu based RCSCNO materials. Measurements of the lower critical field curve, dc irreversibility line, and critical current densities are reported for each of the superconducting NdCSCNO, SmCSCNO, and EuCSCNO compounds. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. RP BENNAHMIAS, M (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94550, USA. NR 30 TC 2 Z9 2 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 OCT PY 1993 VL 22 IS 10 BP 1189 EP 1193 DI 10.1007/BF02818059 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800003 ER PT J AU SHI, DL AF SHI, DL TI FACTORS DOMINATING THE TRANSPORT CRITICAL-CURRENT BEHAVIOR IN HIGH-T(C) SUPERCONDUCTORS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE CRITICAL CURRENT DENSITY; GRAIN BOUNDARY; HIGH-TC; MICROSTRUCTURE; WEAK LINKS ID HIGH-TC SUPERCONDUCTORS; GRAIN-BOUNDARIES; MAGNETIC-RELAXATION; YBA2CU3OX; FIELD; MICROSTRUCTURE; DEPENDENCE AB The previous experimental studies on transport J(c) and grain boundary (micro)structure of YBaCu3Ox have been summarized. A novel interpretation is proposed for the transport current behavior in high-T(c) superconductors. Based on extensive transport, magnetization, and electron microscopy experimental data reported previously, we show that the transport J(c)(H) characteristics in high-T(c) superconductors are dominated by the portion of strongly coupled regions at the grain boundaries. As a result of inhomogeneity of the grain boundaries, the coupling strength varies and causes a distribution of J(gb) (intergranular J(c)) related to the fluctuations of the superconducting order parameter at the boundary area. We also discuss formation mechanisms of strongly coupled regions in bulk materials, and we present inductive methods that can be used to determine the coupling strength of a material. RP SHI, DL (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 28 TC 6 Z9 6 U1 1 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 OCT PY 1993 VL 22 IS 10 BP 1211 EP 1219 DI 10.1007/BF02818063 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800007 ER PT J AU MILLER, DJ HOLESINGER, TG ROUTBORT, JL GORETTA, KC CHUMBLEY, LS AF MILLER, DJ HOLESINGER, TG ROUTBORT, JL GORETTA, KC CHUMBLEY, LS TI CRYSTALLIZATION AND STABILITY OF THE BI2SR2CACU2OX SUPERCONDUCTOR SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE ANALYTICAL ELECTRON MICROSCOPY; BI-2212; CRITICAL CURRENT DENSITY; FLUX PINNING; HOT ISOSTATIC PRESSING; MECHANICAL CREEP; MELT PROCESSING; SPLAT-QUENCHED GLASS; OXYGEN PARTIAL PRESSURE ID CA-CU-O; GLASS-CERAMICS; BI; SYSTEM; OXYGEN; FILMS AB A basic study of the stability of the Bi2Sr2CaCu2Ox phase has been carried out in order to identify the composition and processing conditions for optimum superconducting properties. Analytical electron microscopy has been used to follow the crystallization of this phase during annealing in the solid state as well as from the melt. The crystal chemistry and phase purity is found to depend strongly on the processing conditions. Significant differences in crystallization behavior may be related to kinetic limitations of oxygen transport. The Bi2Sr2CaCu2Ox phase has also been subjected to thermomechanical processing in order to improve our understanding of the deformation processes involved during fabrication of wires and tapes. It has been found that mechanical deformation can have significant effects on the microstructure of the material which in turn result in changes in superconducting properties. C1 ARGONNE NATL LAB,CTR SCI & TECHNOL SUPERCONDUCTIV,ARGONNE,IL 60439. ARGONNE NATL LAB,ARGONNE,IL 60439. AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP MILLER, DJ (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 22 TC 5 Z9 5 U1 0 U2 2 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 OCT PY 1993 VL 22 IS 10 BP 1263 EP 1268 DI 10.1007/BF02818070 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800014 ER PT J AU KRAMER, MJ MCCALLUM, RW MARGULIES, L ARRASMITH, SR HOLESINGER, TG AF KRAMER, MJ MCCALLUM, RW MARGULIES, L ARRASMITH, SR HOLESINGER, TG TI TECHNIQUES FOR TEXTURING CERAMIC SUPERCONDUCTORS FROM AN AMORPHOUS PRECURSOR SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE AMORPHOUS; BI-SR-CA-CU-O; BI-SR-CA-CU-O+AG; TEM; TEXTURING; XRD ID BI2SR2CACU2OX; OXYGEN; TAPES AB Amorphous Bi2Sr2CaCu2O8 (Bi-2212) was crystallized under a uniaxial load of 1500 N at temperatures up to 880-degrees-C without Ag and 850-degrees-C with Ag to induce texture. Well textured samples (19 mm in diameter and 0.15 mm thick) were obtained for samples heated to within 99% of the melting temperature and quenched for samples with and without Ag. The rate limiting step for formation of the Bi-2212 from the amorphous precursor is a diffusion limited intercalation of (SrCa)CuO2 into Bi2Sr2CuO6 (Bi-2201) at T > 600-degrees-C. Samples rapidly heated to within a few degrees of the melting temperature and quenched show 20 to 30% Bi-2201 layers within the Bi-2212 structure. Annealing these samples at 850-degrees-C for > 60 h eliminates most of the Bi-2201 layers resulting in sharper superconducting transitions and higher intracrystalline critical currents with no adverse effects on grain size or texture. It is more difficult to remove the intercalations in the Ag added material. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP KRAMER, MJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011, USA. NR 16 TC 6 Z9 6 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 OCT PY 1993 VL 22 IS 10 BP 1269 EP 1274 DI 10.1007/BF02818071 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800015 ER PT J AU BALACHANDRAN, U ZHONG, W YOUNGDAHL, CA POEPPEL, RB AF BALACHANDRAN, U ZHONG, W YOUNGDAHL, CA POEPPEL, RB TI MICROSTRUCTURE AND ASSOCIATED PROPERTIES OF YBCO SUPERCONDUCTORS PREPARED BY MELT-PROCESSING TECHNIQUES SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE FLUX PINNING; FLUX TRAPPING; LEVITATION FORCE; MELT-PROCESSING; SEEDING ID CRITICAL CURRENT-DENSITY; YBACUO SUPERCONDUCTORS; OXIDE SUPERCONDUCTORS; HIGH-JC; YBA2CU3OX; GROWTH AB From the standpoint of applications, melt-processed bulk YBa2Cu3Ox (YBCO) superconductors are of considerable interest. In this paper, we studied the microstructure and levitation force of melt-processed YBCO, YBCO plus Y2BaCuO5, and YBCO + Pt. Large single-crystal samples, grown by a seeding technique, were also studied. The levitation force was highest in melt-processed samples made by the seeding technique. RP BALACHANDRAN, U (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 24 TC 21 Z9 21 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 OCT PY 1993 VL 22 IS 10 BP 1285 EP 1288 DI 10.1007/BF02818074 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800018 ER PT J AU GORETTA, KC WU, CT LANAGAN, MT POEPPEL, RB SCHWARTZ, J WU, S AF GORETTA, KC WU, CT LANAGAN, MT POEPPEL, RB SCHWARTZ, J WU, S TI PURE AND LITHIUM-DOPED BI2SR2CACU2OX SILVER-CLAD TAPES SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE BI-SR-CA-CU-O; CONDUCTOR; CURRENT DENSITY; DOPING; FABRICATION; LITHIUM ID CA-CU-O; CURRENT-DENSITY; PHASE-RELATIONS; MAGNETIC-FIELD; 2-2-1-2 WIRES; OXIDE TAPES; SUPERCONDUCTOR; MICROSTRUCTURE; TEMPERATURE; DEPENDENCE AB Silver-clad tapes with transport J(c) values to 10(5) A/cm2 at T = 4.2K were produced by a powder-in-tube process. Moderate reductions per pass and proper tape thicknesses were essential for producing good conductors. Partial-melt sintering, followed by a solid-state heat treatment, produced microstructures consisting of large, well-aligned 2212 grains and alkaline-earth cuprate phases. The deleterious effects of these second phases were minimized by proper heat treatments, but further reductions in the sizes and concentrations of these phases are needed to improve J(c) values substantially. Lithium additions raised T(c), improved flux pinning, and lowered melting points. They offer hope that the presence of alkaline-earth cuprates can be limited through use of low-temperature heat treatments. C1 UNIV ILLINOIS,DEPT NUCL ENGN,URBANA,IL 61801. RP GORETTA, KC (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. RI Schwartz, Justin/D-4124-2009 OI Schwartz, Justin/0000-0002-7590-240X NR 39 TC 3 Z9 3 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 OCT PY 1993 VL 22 IS 10 BP 1289 EP 1294 DI 10.1007/BF02818075 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800019 ER PT J AU HALDAR, P HOEHN, JG BALACHANDRAN, U MOTOWIDLO, LR AF HALDAR, P HOEHN, JG BALACHANDRAN, U MOTOWIDLO, LR TI PROCESSING AND TRANSPORT-PROPERTIES OF HIGH-J(C) SILVER-CLAD BI-2223 TAPES AND COILS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP ON HIGH TEMPERATURE SUPERCONDUCTORS, AT THE 122ND ANNUAL MEETING OF THE METALLURGICAL-SOC CY FEB, 1993 CL DENVER, CO SP METALLURG SOC DE CRITICAL CURRENT DENSITY; PANCAKE COILS; POWDER-IN-TUBE; SILVER CLADDING; THERMOMECHANICAL PROCESSING ID WIRES AB The powder-in-tube process has been used to fabricate long lengths of flexible, high-J(c), silver-clad Bi-2223 HTS conductors. By improving thermomechanical processing and precursor powder preparation, we have succeeded in achieving J(c) values of greater-than-or-equal-to 4 x 10(4) A/cm2 at liquid nitrogen (77K) temperature and >10(5) A/cm2 at liquid helium (4.2K) and liquid neon (27K) temperatures in short tape samples. Detailed measurements with high applied magnetic fields are reported. Several long tapes up to 10 m in length have also been fabricated and cowound into small superconducting pancake coils by the ''wind-and react' approach. Transport measurements at 77 and 4.2K for these coils are also reported. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. IGC ADV SUPERCONDUCTORS INC,WATERBURY,CT 06704. RP HALDAR, P (reprint author), INTERMAGNET GEN CORP,GUILDERLAND,NY 12084, USA. NR 6 TC 3 Z9 3 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 OCT PY 1993 VL 22 IS 10 BP 1295 EP 1297 DI 10.1007/BF02818076 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA MA738 UT WOS:A1993MA73800020 ER PT J AU ASSANIS, D KARVOUNIS, E SEKAR, R MARR, W AF ASSANIS, D KARVOUNIS, E SEKAR, R MARR, W TI HEAT RELEASE ANALYSIS OF OXYGEN-ENRICHED DIESEL COMBUSTION SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article AB A heat release correlation for oxygen-enriched diesel combustion is being developed through heat release analysis of cylinder pressure data from a single-cylinder diesel engine operating under various levels of oxygen enrichment. Results show that standard combustion correlations available in the literature do not accurately describe oxygen-enriched diesel combustion. A novel functional form is therefore proposed, which is shown to reproduce measured heat release profiles closely, under different operating conditions and levels of oxygen enrichment. The mathematical complexity of the associated curve-fitting problem is maintained at the same level of difficulty as for standard correlations. When the novel correlation is incorporated into a computer simulation of diesel engine operation with oxygen enrichment, the latter predicts pressure traces in excellent agreement with measured pressure data. This demonstrates the potential of the proposed combustion simulation to guide the application of oxygen-enriched technology successfully to a variety of multicylinder diesel systems. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP ASSANIS, D (reprint author), UNIV ILLINOIS,URBANA,IL 61801, USA. NR 9 TC 4 Z9 4 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD OCT PY 1993 VL 115 IS 4 BP 761 EP 768 DI 10.1115/1.2906772 PG 8 WC Engineering, Mechanical SC Engineering GA ME263 UT WOS:A1993ME26300013 ER PT J AU DAWSON, PR FOLLANSBEE, PS AF DAWSON, PR FOLLANSBEE, PS TI THE VARIABLE THRESHOLD ROD EXPERIMENT - A COMPARISON OF MEASURED AND COMPUTED DEFORMATIONS SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID KINETICS AB A novel experiment has been developed to induce inhomogeneous deformations under simple extension boundary conditions. By appropriate prior cold working of stock material and fabrication of test specimens with tailored dimensions, the location of the deformation zones along the gage length of tensile specimens was controlled. By design, the deformations were chosen to concentrate either toward the harder or softer ends of the specimens. The experiment provides a sensitive test to judge the ability of constitutive models to replicate the behavior of metals undergoing inhomogeneous deformation. A comparison of experimental results with simulated response using an isotropic state variable model is presented. C1 LANL,DIV LEADER MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP DAWSON, PR (reprint author), CORNELL UNIV,SIBLEY SCH MECH & AEROSP ENGN,ITHACA,NY 14853, USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD OCT PY 1993 VL 115 IS 4 BP 446 EP 454 DI 10.1115/1.2904244 PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA ME172 UT WOS:A1993ME17200019 ER PT J AU MURPHY, CE JOHNSON, TL AF MURPHY, CE JOHNSON, TL TI VEGETATIVE UPTAKE OF TC-99 FROM BURIED, SOLIDIFIED, LOW-LEVEL RADIOACTIVE-WASTE SO JOURNAL OF ENVIRONMENTAL QUALITY LA English DT Article ID TC; BEHAVIOR AB At the Savannah River Site, it is planned to dispose of liquid, low-level nuclear waste by incorporating the waste into a solid, concrete waste form called saltstone. Saltstone monoliths will be buried in clay-capped, subterranean vaults. Although the vault/cap burial system is designed to severely limit the access of vegetative roots to the saltstone, a study was begun in 1984 to determine the potential for root uptake of radionuclides, in case an unforeseen accident should cause exposure of the buried saltstone. Thirty-two lysimeters were designed, constructed, and filled with soil. Saltstone samples, containing the liquid, low-level supernate from a waste disposal demonstration program, were buried in some of the lysimeters. The blocks were placed at varying depths to investigate the relationship between source depth and plant uptake. Other lysimeters, not containing saltstone, were used as controls. Crops, grass, and trees were planted in the lysimeters and sampled periodically to determine radionuclide concentrations. Water samples also were collected from the lysimeter sumps and analyzed for radionuclide content. In the 5 yr following establishment of the lysimeters, only technetium-99 (Tc-99) and cesium-137 (Cs-137) could be detected at elevated concentrations in the vegetation. The Cs-137 concentration difference between the plants grown in control and saltstone lysimeters was so small that the difference was only barely detectible against background. The Tc-99 concentration was significantly higher in the vegetation and the sump water of the lysimeters containing saltstone, when compared to the control lysimeters. The Tc-99 uptake by the vegetation appears to be related to release of the Tc-99 from the saltstone into the soil water. The Tc-99 concentration in vegetation and sump waters shows a similar pattern, including an initial period of very low concentrations followed by a coincident build-up period and a period of relatively uniform concentration. Vegetative uptake factors were calculated for uptake of Tc'' from soil water. The results were very similar for the vegetative parts of all the species grown, 111 to 376 (nBq/kg(vegetation))/(nBq/kg(water)). The uptake factor calculated for the seeds of crops was less by a factor of 100 than the uptake factor for vegetative parts. RP MURPHY, CE (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER SITE,AIKEN,SC 29808, USA. NR 12 TC 13 Z9 13 U1 0 U2 2 PU AMER SOC AGRONOMY PI MADISON PA 677 S SEGOE RD, MADISON, WI 53711 SN 0047-2425 J9 J ENVIRON QUAL JI J. Environ. Qual. PD OCT-DEC PY 1993 VL 22 IS 4 BP 793 EP 799 PG 7 WC Environmental Sciences SC Environmental Sciences & Ecology GA MG004 UT WOS:A1993MG00400022 ER PT J AU TERRONES, G CHEN, CF AF TERRONES, G CHEN, CF TI CONVECTIVE STABILITY OF GRAVITY-MODULATED DOUBLY CROSS-DIFFUSIVE FLUID LAYERS SO JOURNAL OF FLUID MECHANICS LA English DT Article ID DIRECTIONAL SOLIDIFICATION; THERMOSOLUTAL CONVECTION; ONSET; INSTABILITY; BENARD AB A stability analysis is undertaken to theoretically study the effects of gravity modulation and cross-diffusion on the onset of convection in horizontally unbounded doubly diffusive fluid layers. We investigate the stability of doubly stratified incompressible Boussinesq fluid layers with stress-free and rigid boundaries when the stratification is either imposed or induced by Soret separation. The stability criteria are established by way of Floquet multipliers of the amplitude equations. The topology of neutral curves and stability boundaries exhibits features not found in modulated singly diffusive or unmodulated multiply diffusive fluid layers. A striking feature in gravity-modulated doubly cross-diffusive layers is the existence of bifurcating neutral curves with double minima, one of which corresponds to a quasi-periodic asymptotically stable branch and the other to a subharmonic neutral solution. As a consequence, a temporally and spatially quasi-periodic bifurcation from the basic state is possible, in which case there are two incommensurate critical wavenumbers at two incommensurate onset frequencies at the same Rayleigh number. In some instances, the minimum of the subharmonic branch is more sensitive to small parameter variations than that of the quasi-periodic branch, thus affecting the stability criteria in a way that differs substantially from that of unmodulated layers. C1 UNIV ARIZONA, DEPT AEROSP & MECH ENGN, TUCSON, AZ 85721 USA. RP TERRONES, G (reprint author), PACIFIC NW LAB, DEPT ANALYT SCI, RICHLAND, WA 99352 USA. OI Terrones, Guillermo/0000-0001-8245-5022 NR 26 TC 15 Z9 15 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD OCT PY 1993 VL 255 BP 301 EP 321 DI 10.1017/S0022112093002496 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA MF298 UT WOS:A1993MF29800014 ER PT J AU DUBOIS, DF HANSSEN, A ROSE, HA RUSSELL, D AF DUBOIS, DF HANSSEN, A ROSE, HA RUSSELL, D TI SPACE AND TIME DISTRIBUTION OF HF EXCITED LANGMUIR TURBULENCE IN THE IONOSPHERE - COMPARISON OF THEORY AND EXPERIMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA-DENSITY DEPLETIONS; DUCT-MODEL EXPLANATION; PARAMETRIC-INSTABILITIES; NONLINEAR EVOLUTION; HEATING EXPERIMENTS; NUMERICAL TEST; LINE SPECTRA; ARECIBO; RADAR; WAVES AB The predictions of strong Langmuir turbulence (SLT) theory are compared with radar observations of HF induced turbulence at Arecibo and Tromso. The altitude distribution of turbulence observed in the cold start experiments of Fejer et al. (1991) imply that the ionospheric electron density profile is modified by the induced turbulence. The preconditioned observations at Arecibo and the Tromso observations also appear to require a ''disturbed'' profile with several percent density fluctuations. With such density modifications postulated we conclude that SLT theory is in, at least, qualitative agreement with a large body of observations. Specifically SLT theory predicts, as part of a unified theory, and in distinction to the weak turbulence approximation, at least four unique physical signatures which can be compared to observations: (1.) A caviton continuum plus free mode peak in the plasma line power spectrum near reflection altitude for Arecibo conditions. (2.) A truncated decay-cascade spectrum at lower altitudes (or densities). (3.) A continuous spectrum underlying the decay-cascade spectrum. (4.) A zero frequency feature in the ion line power spectrum directly related to caviton dynamics. We find that there is sufficient ponderomotive pressure due to the Airy-layered, induced Langmuir turbulence, to modify the electron density profile in a manner consistent with the time behavior of unpreconditioned Arecibo observations. C1 UNIV OSLO,INST THEORET ASTROPHYS,N-0315 OSLO,NORWAY. LODESTAR RES CORP,BOULDER,CO 80301. RP DUBOIS, DF (reprint author), LOS ALAMOS NATL LAB,DIV THEORET MS B262,LOS ALAMOS,NM 87545, USA. NR 59 TC 83 Z9 83 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 JI J. Geophys. Res-Space Phys. PD OCT 1 PY 1993 VL 98 IS A10 BP 17543 EP 17567 DI 10.1029/93JA01469 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MA457 UT WOS:A1993MA45700030 ER PT J AU HASAN, A KNAPP, FF KILBOURN, MR BUCHSBAUM, DJ AF HASAN, A KNAPP, FF KILBOURN, MR BUCHSBAUM, DJ TI NEW AZOMYCIN ACYCLONUCLEOSIDES - SYNTHESIS AND BIODISTRIBUTION OF RADIOHALOGENATED ANALOGS IN TUMOR-BEARING MICE SO JOURNAL OF HETEROCYCLIC CHEMISTRY LA English DT Article ID CEREBRAL PERFUSION AGENTS; FATTY-ACIDS; MISONIDAZOLE; IODIDE; RIBOSIDE AB The design, synthesis and biological activities of several acyclonucleoside analogues related to misonidazole are described. The hydroxy-5, bromo-6, iodo-7, and fluoro-8 derivatives of ethoxymethylazomycin and iodopropenyloxymethylazomycin (12) have been prepared. Alkylation of silylated azomycin with haloethoxy-methylene chloride gave the corresponding acyclonucleosides. Similarly, propargyloxymethylene chloride gave propargyloxymethylazomycin (10), which after hydrostannylation and subsequent iododestannylation yielded iodopropenyloxymethylazomycin (12). The radiolabeled [I-125] or [F-18] compounds were prepared from the corresponding substrates. Biodistribution results of the radiolabeled analogues in mice showed that compound 7 had good tumor uptake (2.0% injected dose/g at 1 hour). The high radioactive levels in blood and stomach, however, were perhaps due to in vivo deiodination or metabolism. Compound [I-125]-12 showed the highest tumor uptake (4.8 and 3.6% injected dose/g at 1 and 4 hours respectively) of all of the compounds tested. Relatively low thyroid uptake of radioactivity in mice dosed with compound [I-125]-12 indicates significantly reduced in vivo deiodination in comparison to compound [I-125]-7. C1 OAK RIDGE NATL LAB,DIV HLTH SCI RES,NUCL MED GRP,OAK RIDGE,TN 37831. UNIV MICHIGAN,MED CTR,DEPT INTERNAL MED,ANN ARBOR,MI 48109. UNIV ALABAMA,DEPT RADIAT ONCOL,BIRMINGHAM,AL 35233. NR 31 TC 3 Z9 3 U1 0 U2 0 PU HETERO CORPORATION PI TAMPA PA BOX 20285, TAMPA, FL 33622-0285 SN 0022-152X J9 J HETEROCYCLIC CHEM JI J. Heterocycl. Chem. PD OCT-NOV PY 1993 VL 30 IS 5 BP 1351 EP 1355 PG 5 WC Chemistry, Organic SC Chemistry GA MM424 UT WOS:A1993MM42400029 ER PT J AU ATLURU, D GUDAPATY, S ODONNELL, MP WOLOSCHAK, GE AF ATLURU, D GUDAPATY, S ODONNELL, MP WOLOSCHAK, GE TI INHIBITION OF HUMAN MONONUCLEAR CELL-PROLIFERATION, INTERLEUKIN SYNTHESIS, MESSENGER-RNA FOR IL-2, IL-6, AND LEUKOTRIENE-B(4) SYNTHESIS BY A LIPOXYGENASE INHIBITOR SO JOURNAL OF LEUKOCYTE BIOLOGY LA English DT Article DE PERIPHERAL BLOOD MONONUCLEAR CELLS; INTERLEUKIN-2; INTERLEUKIN-6; LEUKOTRIENE-B(4) ID TYROSINE KINASE INHIBITOR; 5-LIPOXYGENASE INHIBITOR; ARACHIDONIC-ACID; SIGNAL TRANSDUCTION; ACTIVATION; PHOSPHORYLATION; GENISTEIN; CYCLOSPORINE; EXPRESSION; FK-506 AB Human peripheral blood mononuclear cells (PBMCs) were cultured in vitro with various stimuli and in the presence or absence of a 5-lipoxygenase (5-LO) inhibitor, A-63162, to measure its effects on PBMC proliferation, interleukin-2 receptor (IL-2R) expression, interleukin-2 (IL-2) synthesis, interleukin-6 (IL-6) synthesis, and accumulation of messenger RNA for IL-2 or IL-6. A-63162 inhibited PBMC proliferation stimulated by phytohemagglutinin (PHA) and phorbol myristate acetate (PMA) plus A23187, IL-2 receptor expression stimulated by PHA, and IL-2 or IL-6 synthesis induced by PHA plus PMA or PMA plus A23187. At the same concentration, A-63162 inhibited accumulation of mRNA for IL-2 or IL-6 and also inhibited leukotriene B4 (LTB4) synthesis. Our data indicate that the 5-LO inhibitor A-63162 has immunosuppressive activity that may be due to inhibition of LTB4 production or to direct inhibitory actions of A-63162 on IL-2 and IL-6 synthesis. C1 HENNEPIN CTY MED CTR,REG KIDNEY DIS PROGRAM,DEPT MED,DIV NEPHROL,MINNEAPOLIS,MN 55415. ANDHRA UNIV,DEPT BIOCHEM,WALTAIR 530003,ANDHRA PRADESH,INDIA. ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 FU NCI NIH HHS [CA46964] NR 30 TC 15 Z9 15 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0741-5400 J9 J LEUKOCYTE BIOL JI J. Leukoc. Biol. PD OCT PY 1993 VL 54 IS 4 BP 269 EP 274 PG 6 WC Cell Biology; Hematology; Immunology SC Cell Biology; Hematology; Immunology GA MA318 UT WOS:A1993MA31800001 PM 8409748 ER PT J AU FTHENAKIS, VM AF FTHENAKIS, VM TI HGSPRAY - A COMPLETE MODEL OF SPRAYING UNCONFINED GASEOUS RELEASES SO JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES LA English DT Article DE MODEL; WATER SPRAYING SYSTEM; HYDROFLUORIC ACID RELEASES ID TOXIC GASES AB The model presented here, HGSPRAY, is an expanded and refined version of the GAS-SPRAY model presented by this author in an earlier study. HGSPRAY simulates the momentum, mass and energy interactions between several water sprays and a turbulent plume of a heavy gas (HG) in air; the model can predict the flow velocities, temperature, water vapour and gas concentration fields in two-dimensional large geometries for spraying in any direction. The model has been verified with the data obtained from the Hawk field experiments of hydrofluoric acid (HF) mitigation, at the DOE Nevada Test Site. RP FTHENAKIS, VM (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 17 TC 11 Z9 11 U1 1 U2 1 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0950-4230 J9 J LOSS PREVENT PROC JI J. Loss Prev. Process Ind. PD OCT PY 1993 VL 6 IS 5 BP 327 EP 331 DI 10.1016/S0950-4230(05)80007-5 PG 5 WC Engineering, Chemical SC Engineering GA MC990 UT WOS:A1993MC99000007 ER PT J AU WU, RQ FREEMAN, AJ AF WU, RQ FREEMAN, AJ TI MAGNETISM OF FE ON W(OO1) AND THE EFFECTS OF OXYGEN-ADSORPTION SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article ID METASTABLE-ATOM-DEEXCITATION; ELECTRONIC-STRUCTURE; SURFACE RESONANCES; W(110); FILMS; FE(110); W(001); SPECTROSCOPY; AG; MONOLAYERS AB Structural, electronic and magnetic properties of monolayer and bilayer Fe on W(001), denoted by 1Fe/W(001), and 2Fe/W(001), and oxygen on 2Fe/W(001) have been calculated using the full potential linearized augmented plane wave method. The ferromagnetism of the Fe monolayer is found to be removed by the W(001) substrate (even as a metastable state) for the monolayer Fe/W(001) system; the AFM coupling becomes the ground state. Interestingly, an additional Fe overlayer can activate the ferromagnetism of the 'dead' Fe layer - which indicates the sensitivity of the magnetism to the overlayer thickness for Fe/W(001) especially around monolayer coverages. The bilayer Fe adopts a tetragonal (rather than bcc) structure on W(001), which keeps the interatomic distance between two Fe layers identical to that in bulk bcc Fe (4.69 a.u.). Oxygen adsorption induces a large change of the atomic structure and the Fe magnetic moment (an increase in the top layer and a reduction in the underlayer). Magnetic Fe overlayers induce a large magnetic moment of 0.19-0.22 mu(B) on the interfacial W atoms and a very large magnetic hyperfine interaction. The spin density at EF, m(r,E(F)), is negative in the surface-vacuum region for the bilayer Fe/W(001) system, but becomes positive on oxygen adsorption. C1 NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RI Wu, Ruqian/C-1395-2013 OI Wu, Ruqian/0000-0002-6156-7874 NR 43 TC 15 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 EI 1873-4766 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD OCT PY 1993 VL 127 IS 3 BP 327 EP 345 DI 10.1016/0304-8853(93)90049-8 PG 19 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA MF529 UT WOS:A1993MF52900012 ER PT J AU RAWERS, JC KIKUCHI, M AF RAWERS, JC KIKUCHI, M TI NITROGEN CONCENTRATION IN FE-CR-MN ALLOYS SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article; Proceedings Paper CT INTERNATIONAL AEROMAT 93 CONF : PROCESSING/SYNTHESIS OF MATERIALS CY JUN 06-09, 1993 CL ANAHEIM, CA SP AMER SOC MET INT DE FE-CR-MN STEELS; NITROGEN; SIEVERTS LAW; STEEL; THERMODYNAMICS ID SOLUBILITY; IRON AB Nitrogen addition to iron alloys improves mechanical properties. The composition of the alloy as well as the melt pressure influences nitrogen concentration. In this US Bureau of Mines study, nitrogen concentrations in Fe-Cr-Mn alloys were determined. New thermodynamic expressions were derived to relate nitrogen concentration to alloy composition and melt pressure. These expressions included nonlinear terms, such as pressure-concentration and Cr-Mn terms. C1 TOKYO INST TECHNOL,TOKYO 152,JAPAN. RP RAWERS, JC (reprint author), US BUR MINES,ALBANY RES CTR,ALBANY,OR, USA. NR 20 TC 3 Z9 3 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD OCT PY 1993 VL 2 IS 5 BP 651 EP 658 DI 10.1007/BF02650053 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA MH538 UT WOS:A1993MH53800003 ER PT J AU SINGH, JP JOO, J VASANTHAMOHAN, N POEPPEL, RB AF SINGH, JP JOO, J VASANTHAMOHAN, N POEPPEL, RB TI ROLE OF AG ADDITIONS IN THE MICROSTRUCTURAL DEVELOPMENT, STRAIN TOLERANCE, AND CRITICAL-CURRENT DENSITY OF AG-SHEATHED BSCCO SUPERCONDUCTING TAPES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID HIGH-FIELD; WIRES AB Ag-sheathed tapes of Bi-Sr-Ca-Cu-O (BSCCO) and BSCCO-Ag superconducting cores were made by a powder-in-tube technique and subjected to repeated cycles of pressing and heat treatments. These thermomechanical treatments resulted in enhanced texturing and grain growth that improved the critical current density (J(c)). Additions of Ag to the BSCCO core further increased texturing and brought an additional improvement in J(c). Strain tolerance of the tapes was evaluated by measuring J(c) before and after application of a predetermined level of tensile strain in a uniaxial mode. The fraction of J(c) retained after the strain application was higher in the BSCCO-Ag composite tapes than in the monolithic BSCCO. For a 1.2% applied strain, 90% of the initial J(c) was retained in the BSCCO-Ag composite tape, compared to only 40% in the monolithic BSCCO tapes. The higher strain tolerance of the BSCCO-Ag tapes may be related to improved mechanical properties (strength, flexibility, and fracture toughness) and grain connectivity due to Ag addition. RP SINGH, JP (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 19 TC 43 Z9 43 U1 0 U2 1 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 OCT PY 1993 VL 8 IS 10 BP 2458 EP 2464 DI 10.1557/JMR.1993.2458 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100005 ER PT J AU CHEN, N ROTHMAN, SJ ROUTBORT, JL AF CHEN, N ROTHMAN, SJ ROUTBORT, JL TI DIFFUSION OF SR IN BI2SR2CAN-1CUNO2N+4 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID TRACER DIFFUSION; BI2SR2CACU2OX; YBA2CU3O7-DELTA; SUPERCONDUCTOR; PHASE; COMPOUND; OXYGEN; RANGE AB Tracer diffusion of Sr-85 in polycrystalline Bi2Sr2Can-1CunO2n+4 has been investigated for n = 1, 2, and 3 in an oxygen atmosphere between 775 and 850-degrees-C. A radiotracer serial-sectioning technique was used to measure the concentration profiles, which were fit to a solution of the diffusion equation to calculate the diffusivities. The activation energies were 403, 553, and 519 kJ/mole, for n = 1, 2, and 3, respectively. However, the absolute values of D for the various layered superconductors did not differ by more than an order of magnitude over the measured temperature range. The diffusivity of Sr at 800-degrees-C for n = 1 or 2 over an oxygen partial pressure range of 10(3) to 10(5) Pa increased as the pressure decreased. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NR 24 TC 9 Z9 9 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 OCT PY 1993 VL 8 IS 10 BP 2465 EP 2470 DI 10.1557/JMR.1993.2465 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100006 ER PT J AU ASTA, M DEFONTAINE, D VANSCHILFGAARDE, M AF ASTA, M DEFONTAINE, D VANSCHILFGAARDE, M TI 1ST-PRINCIPLES STUDY OF PHASE-STABILITY OF TI-AL INTERMETALLIC COMPOUNDS SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID GROUND-STATE STRUCTURES; BINARY HCP ALLOYS; NEIGHBOR INTERACTIONS; ELECTRONIC-STRUCTURE; ISING-MODEL; THERMODYNAMIC PROPERTIES; CRYSTAL-STRUCTURE; L12 COMPOUNDS; METAL ALLOYS; SYSTEM AB Thermodynamic and structural properties of fcc- and hcp-based Ti-Al alloys are calculated from first-principles and are used to perform an ab initio study of phase stability for the intermetallic compounds in this system. The full potential linear muffin tin orbital method is used to determine heats of formation and other zero-temperature properties of 9 fcc- and 7 hcp-based intermetallic compounds, as well as of elemental fcc and hcp Ti and Al. From the results of these calculations, sets of effective cluster interactions are derived and are used in a cluster variation method calculation of the solid-state portion of the composition-temperature phase diagram for fcc- and hcp-based alloy phases. The results of our calculations are compared with those of experimental studies of stable and metastable phases in the Ti-Al system. C1 LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. RP ASTA, M (reprint author), UNIV CALIF BERKELEY, DEPT MAT SCI & MINERAL ENGN, BERKELEY, CA 94720 USA. NR 80 TC 71 Z9 72 U1 1 U2 9 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD OCT PY 1993 VL 8 IS 10 BP 2554 EP 2568 DI 10.1557/JMR.1993.2554 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100017 ER PT J AU ANNIS, BK PEDRAZA, DF WITHROW, SP AF ANNIS, BK PEDRAZA, DF WITHROW, SP TI TOPOGRAPHICAL CHANGES INDUCED BY HIGH-DOSE CARBON-BOMBARDMENT OF GRAPHITE SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; ATOMIC RESOLUTION; ION IMPACTS; SURFACE; DEFECTS; DAMAGE; ENERGY; AIR; TIP AB Highly oriented pyrolytic graphite has been implanted at room temperature with 165 keV C+-ions at doses from 6 x 10(17) to 3 x 10(19) ions/M2. Implantation-induced topographical changes of differing size scales were studied by optical, scanning electron, scanning tunneling, and atomic force microscopies. Defects with atomic resolution are seen for the lower dose implants. The formation of a vacancy line is revealed for the first time. At the higher doses a dendrite-like system of deep surface cracks is observed. This cracking develops as a result of the large basal plane contraction produced by irradiation which generates high shearing stresses between the implanted, damaged surface layer and the underlying material. Two independent systems of ridges have been characterized. One appears to follow a crystallographic direction while the other appears as a dense, intricate, generally curvilinear network with short ramifications. Additional experiments in which both the ion energy and dose rate have been varied indicate that ridge evolution progresses with increased energy and fluence, but is independent of dose rate. It is suggested that the ridge networks may form as a result of C transport by diffusion from the heavily damaged near-surface region or of a tectonic-plate-like motion or both. The geometric features of the ridge networks are related to the subsurface radiation damage as well. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP ANNIS, BK (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 41 TC 9 Z9 9 U1 0 U2 4 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 OCT PY 1993 VL 8 IS 10 BP 2587 EP 2599 DI 10.1557/JMR.1993.2587 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100020 ER PT J AU ROSS, J RUBIN, M GUSTAFSON, TK AF ROSS, J RUBIN, M GUSTAFSON, TK TI SINGLE-CRYSTAL WURTZITE GAN ON (111) GAAS WITH ALN BUFFER LAYERS GROWN BY REACTIVE MAGNETRON SPUTTER-DEPOSITION SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MOLECULAR-BEAM EPITAXY; GALLIUM NITRIDE; FILMS; SUBSTRATE AB We report the growth conditions necessary for highly oriented wurtzite GaN films on (111) GaAs, and single crystal GaN films on (111) GaAs using AlN buffer layers. The GaN films and AlN buffers are grown using rf reactive magnetron sputter deposition. Oriented basal plane wurtzite GaN is obtained on (111) GaAs at temperatures between 550 and 620-degrees-C. However, using a high temperature 200 angstrom AlN buffer layer epitaxial GaN is produced. Crystal structure and quality are measured using x-ray diffraction (XRD), reflection electron diffraction (RED), and a scanning electron microscope (SEM). This is the first report of single crystal wurtzite GaN on (111) GaAs using AIN buffer layers by any growth technique. Simple AlN/GaN heterostructures grown by rf reactive sputter deposition on (111) GaAs are also demonstrated. RP ROSS, J (reprint author), LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,MS 2-300,BERKELEY,CA 94720, USA. NR 20 TC 28 Z9 29 U1 0 U2 4 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 OCT PY 1993 VL 8 IS 10 BP 2613 EP 2616 DI 10.1557/JMR.1993.2613 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100023 ER PT J AU CHANG, HLM ZHANG, TJ ZHANG, H GUO, J KIM, HK LAM, DJ AF CHANG, HLM ZHANG, TJ ZHANG, H GUO, J KIM, HK LAM, DJ TI EPITAXY, MICROSTRUCTURE, AND PROCESSING-STRUCTURE RELATIONSHIPS OF TIO2 THIN-FILMS GROWN ON SAPPHIRE (0001) BY MOCVD SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; GAAS QUANTUM WELLS; PHOTOLUMINESCENCE; CU AB TiO2 thin films have been deposited on sapphire (0001) substrates under various conditions by metal-organic chemical vapor deposition. The structural properties of the deposited films were characterized by x-ray diffraction and transmission electron microscopy. The important growth parameters were found to be the deposition temperature and the deposition rate. The ranges studied for the two parameters were 400 to 850-degrees-C and 10 to 120 angstrom/min, respectively. Depending on the growth conditions, most of the deposited films were either single-phase anatase or rutile, or a mixture of the two. These films were all epitaxial, but none of them were single-crystal films. Three distinct epitaxial relationships were observed between the films and the substrates, and, depending on the growth conditions, a deposited film can contain one, two, or all three of them. The fact that the films we obtained, although epitaxial, were never single crystal is explained based on the consideration of the difference in the rotational symmetries of the substrate surface and the film growth plane. We believe that it should be generally true that, in heteroepitaxial growth, a true single-crystal film can never be obtained as long as the point symmetry group of the substrate surface is not a subgroup of that of the film growth plane. RP CHANG, HLM (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Kim, Hyung-Kook/J-2065-2012 OI Kim, Hyung-Kook/0000-0003-4974-5233 NR 20 TC 22 Z9 23 U1 0 U2 4 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 OCT PY 1993 VL 8 IS 10 BP 2634 EP 2643 DI 10.1557/JMR.1993.2634 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100026 ER PT J AU ZHANG, JG TRACY, CE BENSON, DK DEB, SK AF ZHANG, JG TRACY, CE BENSON, DK DEB, SK TI THE INFLUENCE OF MICROSTRUCTURE ON THE ELECTROCHROMIC PROPERTIES OF LIXWO3 THIN-FILMS .1. ION DIFFUSION AND ELECTROCHROMIC PROPERTIES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AMORPHOUS WO3; ELECTROLYTES AB The chemical diffusion coefficients of lithium ions in LixWO3 films were investigated as a function of lithium concentration and film porosity. Thin films were deposited with different porosities by thermal evaporation of WO3 powder in various partial water pressures. Our results indicate that diffusion coefficients increase with film porosity and decrease with increasing lithium concentration. Large diffusion coefficients that were found for small lithium concentrations appear to be due to the contribution of protons generated from ion exchange reactions between lithium and water incorporated in the film. Simultaneous electrical and in situ optical measurements were carried out to study the effect of porosity on the electrochromic properties of LixWO3. The coloring efficiency Of porous WO3 films increases by approximately 70% when deposited in partial water pressure of 10(-4) Torr, but decreases with further increments in water pressure. RP ZHANG, JG (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 21 TC 69 Z9 69 U1 2 U2 9 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 OCT PY 1993 VL 8 IS 10 BP 2649 EP 2656 DI 10.1557/JMR.1993.2649 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100028 ER PT J AU ZHANG, JG BENSON, DK TRACY, CE DEB, SK AF ZHANG, JG BENSON, DK TRACY, CE DEB, SK TI THE INFLUENCE OF MICROSTRUCTURE ON THE ELECTROCHROMIC PROPERTIES OF LIXWO3 FILMS .2. LIMITING MECHANISMS IN COLORING AND BLEACHING PROCESSES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID THIN-FILMS; WO3; ELECTRODES; MODEL AB Various factors affecting the coloring and bleaching processes of LixWO3 films have been studied. The rate of the coloring process is limited by the decreasing electromotive force in the LixWO3 film and by the components of the series circuit resistance, including the electrolyte resistance and the diffusion impedance within the film. The bleaching process in a thick film is limited by either the space charge or by the diffusion impedance, depending on the experimental conditions. A more complete and quantitative model of the coloring/bleaching process has been developed and shows good agreement with experimental results. Our analysis also indicates that the lithium concentration value of x near the LixWO3/electrolyte interface can greatly exceed its reversible limit during the coloring process, even though the average x value within the film remains much lower than the reversible limit. This phenomenon may introduce some irreversible structural changes in the film, which in turn may constitute one of the film's degradation mechanisms. RP ZHANG, JG (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 20 TC 27 Z9 28 U1 1 U2 3 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 OCT PY 1993 VL 8 IS 10 BP 2657 EP 2667 DI 10.1557/JMR.1993.2657 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA LZ661 UT WOS:A1993LZ66100029 ER PT J AU LEVERMORE, CD ZIMMERMAN, GB AF LEVERMORE, CD ZIMMERMAN, GB TI MODELING CHARGED-PARTICLE LOSS IN A FUEL SHELL MIXTURE SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID LASER COMPRESSION AB The hydrodynamic mixing of shell material into the fuel region of an inertial confinement fusion (ICF) target during compression will suppress the thermonuclear yield due to the loss of charged fusion reaction products to the entrained shell material. Adopting a binary Markovian model for this mixture an exact formula for the fraction of particles lost is derived. C1 UNIV ARIZONA,DEPT MATH,TUCSON,AZ 85721. RP LEVERMORE, CD (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 11 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD OCT PY 1993 VL 34 IS 10 BP 4725 EP 4729 DI 10.1063/1.530367 PG 5 WC Physics, Mathematical SC Physics GA LZ166 UT WOS:A1993LZ16600023 ER PT J AU REHN, LE BIRTCHER, RC AF REHN, LE BIRTCHER, RC TI EXPERIMENTAL STUDIES OF FREE DEFECT GENERATION DURING IRRADIATION - IMPLICATIONS FOR REACTOR ENVIRONMENTS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID MIGRATING DEFECTS; ION-IRRADIATION; DAMAGE; NICKEL AB Over the past several years, systematic experiments have revealed that irradiations which generate energetically dense cascades are much less effective than light-ion, MeV electron, or thermal neutron irradiations at producing freely-migrating defects. In this paper, the systematic results on freely-migrating defect production from ion-irradiation studies are briefly summarized. Difficulties with applying a simple extrapolation of the ion-irradiation results to neutron environments are discussed. This discussion, coupled with our existing knowledge of neutron-induced property changes, indicates that Compton scattering, and the (n, gamma), (n, He) and (n, p) nuclear reactions, are considerably more important for producing freely-migrating defects than was previously realized. RP REHN, LE (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 34 TC 25 Z9 25 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 OCT PY 1993 VL 205 BP 31 EP 39 DI 10.1016/0022-3115(93)90068-A PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200004 ER PT J AU WIEDERSICH, H AF WIEDERSICH, H TI IMPLICATIONS OF DEFECT CLUSTERS FORMED IN CASCADES ON FREE DEFECT GENERATION AND MICROSTRUCTURAL DEVELOPMENT SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID X-RAY SCATTERING; MIGRATING DEFECTS; ION-IRRADIATION; PRODUCTION BIAS; DAMAGE; CU AB A large fraction of the defects produced by irradiation with energetic neutrons or heavy ions originates in cascades; hence, not only increased recombination of vacancy and interstitial defects but also significant clustering of like defects occur. Both processes reduce the number of point defects available for long range migration compared to that available when defects are produced as isolated pairs. Effects of defect clustering will be discussed using a very simplified model: quasi-steady-state distributions of defect clusters develop which can become significant sinks for mobile defects. Although cluster sinks will cause segregation, the finite lifetime of clusters will not lead to lasting, local compositional changes. A transition from highly dense interstitial and vacancy cluster distributions to the void swelling regime occurs when the thermal evaporation of vacancies from small vacancy clusters becomes significant at higher temperatures. Unequal clustering of vacancies and interstitials leads to an imbalance of their fluxes in the matrix and, hence, to unequal contributions to atom transport by interstitials and by vacancies even in the quasi-steady state approximation. RP ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 38 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 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 1993 VL 205 BP 40 EP 51 DI 10.1016/0022-3115(93)90069-B PG 12 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200005 ER PT J AU VETRANO, JS ROBERTSON, IM KIRK, MA AF VETRANO, JS ROBERTSON, IM KIRK, MA TI INFLUENCE OF DILUTE IMPURITIES ON THE EVOLUTION OF DEFECT CASCADES IN NICKEL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ENERGETIC DISPLACEMENT CASCADES; DISLOCATION LOOPS; DYNAMICS AB We have employed transmission electron microscopy to study the formation of vacancy-type dislocation loops from defect cascades produced by a 50 keV Kr+ ion irradiation of Ni and its dilute alloys with Si and Al. An unusual and reproducible dependence of the probability of loop formation and loop size distributions on solute content was found. The results Are explained by impurity caused changes in both the collisional and thermal spike (molten zone) phase of the defect cascade. Specific mechanisms include disruption of focussons by impurities to change the energy density profile within the collision cascade, interruption of replacement collision sequences, and interstitial trapping to reduce recombination during the thermal spike phase. Applying these mechanisms to a statistical distribution of the spatial extent of cascades and to the molten zones, all the experimental observations can be explained. C1 UNIV ILLINOIS, DEPT MAT SCI & ENGN, URBANA, IL 61801 USA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 21 TC 5 Z9 5 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 1993 VL 205 BP 68 EP 73 DI 10.1016/0022-3115(93)90072-7 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200008 ER PT J AU GARNER, FA AF GARNER, FA TI EVOLUTION OF MICROSTRUCTURE IN FACE-CENTERED-CUBIC METALS DURING IRRADIATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID AUSTENITIC STAINLESS-STEELS; MECHANICAL-PROPERTIES; FAST-NEUTRONS; ALLOYS; CREEP; AISI-316; HELIUM; CR; PRECIPITATION; PHOSPHORUS AB When fcc metals and alloys are irradiated at elevated temperatures, they tend to evolve toward saturation microstructures that are independent of the starting state of the metal and the early details of irradiation history. This leads to property changes and rates of dimensional change that also eventually become independent of the starting state. The evolution of microstructure in complex alloys, especially during the transient regime, is usually determined by the complex interaction of many microstructural and microchemical processes. The more complex the alloy, the more difficult it is to identify and define the separate influence of each participating mechanism. The use of irradiation studies conducted on simple metals or model alloys assists in understanding the behavior of alloys of engineering relevance. A review of such studies shows that a number of prevailing perceptions of radiation-induced microstructural evolution are not universally correct. RP GARNER, FA (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 74 TC 45 Z9 46 U1 3 U2 12 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 OCT PY 1993 VL 205 BP 98 EP 117 DI 10.1016/0022-3115(93)90076-B PG 20 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200012 ER PT J AU MAZIASZ, PJ AF MAZIASZ, PJ TI OVERVIEW OF MICROSTRUCTURAL EVOLUTION IN NEUTRON-IRRADIATED AUSTENITIC STAINLESS-STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID SPECTRALLY-TAILORED EXPERIMENTS; RADIATION-INDUCED SEGREGATION; COMPOSITIONAL FLUCTUATIONS; TEMPERATURE-DEPENDENCE; SWELLING RESISTANCE; HFIR IRRADIATION; FUSION-REACTORS; EBR-II; ALLOYS; HELIUM AB Austenitic stainless steels are important structural materials common to several different reactor systems, including light water and fast breeder fission, and magnetic fusion reactors (LWR, FBR, and MFR, respectively). The microstructures that develop in 300 series austenitic stainless steels during neutron irradiation at 60-700-degrees-C include combinations of dislocation loops and networks, bubbles and voids, and various kinds of precipitate phases (radiation-induced, or -enhanced or -modified thermal phases). Many property changes in these steels during neutron irradiation are directly or indirectly related to radiation-induced microstructural evolution. Even more important is the fact that radiation-resistance of such steels during either FBR or MFR irradiation is directly related to control of the evolving microstructure during such irradiation. The purpose of this paper is to provide an overview of the large and complex body of data accumulated from various fission reactor irradiation experiments conducted over the many years of research on microstructural evolution in this family of steels. The data can be organized into several different temperature regimes which then define the nature of the dominant microstructural components and their sensitivities to irradiation parameters (dose, helium/dpa ratio, dose rate) or metallurgical variables (alloy composition, pretreatment). The emphasis in this paper will be on the underlying mechanisms driving the microstructure to evolve during irradiation or those enabling microstructural stability related to radiation resistance. RP MAZIASZ, PJ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN, USA. OI Maziasz, Philip/0000-0001-8207-334X NR 108 TC 134 Z9 136 U1 3 U2 37 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 OCT PY 1993 VL 205 BP 118 EP 145 DI 10.1016/0022-3115(93)90077-C PG 28 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200013 ER PT J AU GELLES, DS AF GELLES, DS TI EFFECTS OF STRESS ON MICROSTRUCTURAL EVOLUTION DURING IRRADIATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID INTERSTITIAL LOOPS; STAINLESS-STEEL; FE-18CR-14NI ALLOY; TENSILE-STRESS; CREEP; NICKEL AB Many theories have been postulated to describe irradiation creep but few have been supported with microstructural evidence. The purpose of this paper is to review microstructural studies of the effects of stress during irradiation to assess the validity of the available irradiation creep theories. Microstructural studies based on high-voltage electron, ion, proton and neutron irradiation are described, with major emphasis placed on interpreting behavior demonstrated in austenitic steels. Special attention is given to work on fast-neutron-irradiated Nimonic PE16, a precipitation-strengthened superalloy. RP GELLES, DS (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 46 TC 8 Z9 8 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 OCT PY 1993 VL 205 BP 146 EP 161 DI 10.1016/0022-3115(93)90078-D PG 16 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200014 ER PT J AU SEKIMURA, N GARNER, FA AF SEKIMURA, N GARNER, FA TI MICROSTRUCTURAL EVOLUTION OF NEUTRON-IRRADIATED FE-CR-NI TERNARY ALLOYS AT HIGH HELIUM GENERATION RATES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID NICKEL AB A series of Fe-Cr-Ni ternary alloys were irradiated to 12-14 dpa in the Oak Ridge Research Reactor (ORR). In this experiment, most of the helium atoms were produced by the Ni-58(n, gamma)Ni-59(n, alpha)Fe-56 sequential reaction, and, therefore, the helium generation rate was almost proportional to the nickel content, ranging from 27 to 58 appm He/dpa in 20 to 45 wt% Ni alloys. Irradiation temperatures were 330, 400, 500 and 600-degrees-C, and the specimen variables were the nickel level, the chromium level and cold-working. The high levels of helium, combined with details of the temperature history, were found to have dominated to microstructural development, sometimes overwhelming and even reversing the action of a given material variable. Microscopy examination showed that there was an unprecedented refinement of cavity microstructure at all temperatures, which accounts for the substantial alterations in both swelling and mechanical properties observed in earlier studies. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP SEKIMURA, N (reprint author), UNIV TOKYO, NUCL ENGN RES LAB, TOKAI, IBARAKI 31911, JAPAN. NR 15 TC 5 Z9 5 U1 0 U2 1 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 OCT PY 1993 VL 205 BP 190 EP 197 DI 10.1016/0022-3115(93)90081-9 PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200017 ER PT J AU GARNER, FA SEKIMURA, N GROSSBECK, ML ERMI, AM NEWKIRK, JW WATANABE, H KIRITANI, M AF GARNER, FA SEKIMURA, N GROSSBECK, ML ERMI, AM NEWKIRK, JW WATANABE, H KIRITANI, M TI INFLUENCE OF DETAILS OF REACTOR HISTORY ON MICROSTRUCTURAL DEVELOPMENT DURING NEUTRON-IRRADIATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID IMPROVED TEMPERATURE CONTROL; NI-CR ALLOYS; AUSTENITIC ALLOYS; MECHANICAL-PROPERTIES; FISSION; HELIUM; EVOLUTION; VARIABLES; SPECTRUM; STEEL AB Microstructurally-oriented irradiation experiments are shown in this paper to be strongly dependent on details of reactor history that frequently are not brought to the experimenter's attention. In some cases, these details can dominate the experiment so as to produce very misleading results. To aid in the design and interpretation of microstructurally-oriented experiments, a number of studies are reviewed to highlight history effects and then guidelines are presented to minimize the impact of reactor history in new experiments. C1 UNIV TOKYO, TOKYO 113, JAPAN. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. UNIV MISSOURI, ROLLA, MO 65401 USA. KYUSHU UNIV, FUKUOKA 812, JAPAN. NAGOYA UNIV, NAGOYA, AICHI 464, JAPAN. RP GARNER, FA (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 32 TC 30 Z9 30 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 OCT PY 1993 VL 205 BP 206 EP 218 DI 10.1016/0022-3115(93)90083-B PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200019 ER PT J AU MOTTA, AT HOWE, LM OKAMOTO, PR AF MOTTA, AT HOWE, LM OKAMOTO, PR TI AMORPHIZATION KINETICS OF ZR3FE UNDER ELECTRON-IRRADIATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID ALLOYS AB Previous investigations using Ar-40-ion bombardments have revealed that Zr3Fe, which has an orthorhombic crystal structure, undergoes an irradiation-induced transformation from the crystalline to the amorphous state. In the present investigation, 0.9 MeV electron irradiations were performed at 28-220 K in a high-voltage electron microscope (HVEM). By measuring the onset, spread and final size of the amorphous region, factoring in the Gaussian distribution of the beam, a kinetic description of the amorphization in terms of dose, dose rate and temperature was obtained. The critical temperature for amorphization by electron irradiation was found to be approximately 220 K, compared with 570-625 K for Ar-40-ion irradiation. Also, the dose-to-amorphization increased exponentially with temperature. Results indicated that the rate of growth of the amorphous region under the electron beam decreased with increasing temperature and the dose-to-amorphization decreased with increasing dose rate. The size of the amorphous region saturated after a given dose, the final size decreasing with increasing temperature, and it is argued that this is related to the existence of a critical dose rate, which increases with temperature, and below which no amorphization occurrs. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP MOTTA, AT (reprint author), ATOM ENERGY CANADA LTD RES,CHALK RIVER LABS,REACTOR MAT RES BRANCH,CHALK RIVER K0J 1J0,ON,CANADA. NR 26 TC 13 Z9 13 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 OCT PY 1993 VL 205 BP 258 EP 266 DI 10.1016/0022-3115(93)90088-G PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200024 ER PT J AU BUI, TX ROBERTSON, IM KLATT, JL AVERBACK, RS KIRK, MA AF BUI, TX ROBERTSON, IM KLATT, JL AVERBACK, RS KIRK, MA TI RADIATION-INDUCED SEGREGATION BEHAVIOR IN RANDOM AND ORDERED FACE-CENTERED-CUBIC MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID DISPLACEMENT AB Radiation-induced segregation has been studied in random solid solution alloys Ni-10%Al and Ni-6%Si, and in the ordered (L1(2) structure) intermetallics Ni3Si and Ni3Al. These materials were irradiated with 2 MeV He+ ions at a temperature between 0.45 and 0.55T(m) and at an ion dose rate of approximately 1 x 10(-4) dpa per second. Subsequent Auger Electron Spectroscopy analysis showed that silicon segregated to the surface in the Ni-6% Si and N3Si alloys, and aluminum segregated away from the near surface region in the Ni-10% Al alloy. The Ni3Al samples exhibited no detectable segregation with respect to depth from the sample surface. The mechanisms that may give rise to this resistance to radiation induced segregation will be examined in terms of the mobility of the alloying constituents, ordering energies and atomic sizes. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP BUI, TX (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801, USA. NR 12 TC 1 Z9 1 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 1993 VL 205 BP 312 EP 316 DI 10.1016/0022-3115(93)90094-F PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200030 ER PT J AU KENIK, EA AF KENIK, EA TI ELEMENTAL INHOMOGENEITIES DEVELOPED IN STAINLESS-STEELS BY RADIATION-INDUCED SEGREGATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID COMPOSITIONAL FLUCTUATIONS; INDUCED SENSITIZATION; IRRADIATED ALLOYS; PHASES AB Radiation-induced segregation (RIS) has been measured by analytical electron microscopy in a number of neutron-irradiated stainless steels stabilized with nickel or manganese. RIS to high angle grain boundaries, cavities, and dislocation loops was observed. Similar enrichment of nickel, silicon, and, in certain cases, phosphorus and depletion of chromium, iron, molybdenum, and manganese occurred at all three of these defect sinks. The origin of matrix composition fluctuations is discussed and an alternate mechanism, based on RIS to the initial dislocation loop microstructure, is suggested. RP KENIK, EA (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 28 TC 10 Z9 10 U1 0 U2 8 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 OCT PY 1993 VL 205 BP 317 EP 323 DI 10.1016/0022-3115(93)90095-G PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200031 ER PT J AU CARTER, RD DAMCOTT, DL ATZMON, M WAS, GS KENIK, EA AF CARTER, RD DAMCOTT, DL ATZMON, M WAS, GS KENIK, EA TI EFFECTS OF PROTON IRRADIATION ON THE MICROSTRUCTURE AND MICROCHEMISTRY OF TYPE-304L STAINLESS-STEEL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID GRAIN-BOUNDARY SEGREGATION; PHOSPHORUS; PRECIPITATION AB A research program has been undertaken to determine the origins of irradiation-assisted stress corrosion cracking (IASCC) in austenitic alloys in light water reactors, and the effect of impurities on IASCC susceptibility. Controlled purity alloys of 304L stainless steel were irradiated with protons at 400-degrees-C to a dose of 1 dpa and analyzed via Auger electron spectroscopy (AES) and scanning transmission electron microscopy (STEM). The alloys investigated were an ultra-high purity (UHP) alloy and UHP alloys containing phosphorus (UHP + P), sulfur (UHP + S), or silicon (UHP + Si). Microstructural and microchemical changes were quantified and compared with literature results for other irradiating species. Following irradiation, the alloys showed dislocation loop formation and growth, ''black dot'' loops, and a change in the nature of the dislocation network. AES and STEM microchemical analysis of the alloys revealed Cr depletion of up to 6 at% and Ni enrichment of up to 6.6 at% at the grain boundaries of the alloys, with more segregation observed in the alloys containing impurities than in the UHP alloy. Significant grain boundary enrichment of P and Si in the UHP + P and UHP + Si alloys, respectively, was also observed. The results of the analyses of proton-irradiated samples are shown to compare favorably with previous studies on samples irradiated with neutrons at or near LWR conditions. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP CARTER, RD (reprint author), UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109, USA. NR 36 TC 28 Z9 28 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 OCT PY 1993 VL 205 BP 361 EP 373 DI 10.1016/0022-3115(93)90101-4 PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200037 ER PT J AU SHIMOMURA, Y GUINAN, MW DELARUBIA, TD AF SHIMOMURA, Y GUINAN, MW DELARUBIA, TD TI ATOMISTICS OF VOID FORMATION IN IRRADIATED COPPER SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID EMBEDDED-ATOM-METHOD; CU; IMPURITIES; ENERGIES; ALLOYS; METALS AB Computer simulations of molecular dynamics and molecular statics are carried out to study the atomistics of void formation in irradiated copper. The isotropic many-body potential of the embedded atom method due to Daw and Baskes [5] is implemented. It is found that a relaxation of tri-vacancy to the Damask-Dienes type of stacking fault tetrahedron (3v-sft) is an important step for the formation of sft. In a 3v-sft, an atom inside a tetrahedral 4v moves with large amplitude at low frequency. To form a void in irradiated copper, gaseous atoms such as hydrogen and helium have to be included in a vacancy cluster. Hydrogen atoms are introduced in the present work. Gaseous atoms suppress the 3v-sft type of relaxation. The structure of hexa-vacancy fluctuates between a sft and a void. A hydrogen atom trapped in a hexa-vacancy preserves the structure of a void. In order to grow such a microvoid to a large void, several hydrogen atoms have to be included in a microvoid. A 8v-void which traps only singly hydrogen atom grows to sft by further absorption of vacancies, while it grows to a void when two hydrogen atoms are trapped. A sft of nine-vacancy which is composed by the mixture of a 6v-sft and 3v-sfts converts to a void when four hydrogen atoms come to the cluster. For the case of the formation of a tetrahedral 10v-void in the core of a displacement damage cascade, the vacancy cluster itself is stable. By absorbing vacancies, it grows to a large sft in which the 10v-void is still included. Even when only one hydrogen atom is trapped in vacancy clusters which grow from the 10v-void and whose size is below the 17-vacancy, it relaxes to avoid. Trapped hydrogen atoms move on the surface of a void and suppress the relaxation of sft. When hydrogen atoms come to a sft which grows from the 10v-void and whose size is larger than the 18-vacancy, it does not relax to a void. It is concluded that the critical step of void nucleation is in the range of six to fifteen vacancies in the presence of gaseous atoms. The preferential formation of voids along dislocation lines, which is observed in irradiated metals, is due to the existence of a high concentration of trapped gaseous atoms along dislocation lines. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP SHIMOMURA, Y (reprint author), HIROSHIMA UNIV,FAC ENGN,HIGASHI KU,HIROSHIMA 724,JAPAN. NR 17 TC 19 Z9 20 U1 1 U2 8 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 OCT PY 1993 VL 205 BP 374 EP 384 DI 10.1016/0022-3115(93)90102-5 PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200038 ER PT J AU GARNER, FA MCCARTHY, JM RUSSELL, KC HOYT, JJ AF GARNER, FA MCCARTHY, JM RUSSELL, KC HOYT, JJ TI SPINODAL-LIKE DECOMPOSITION OF FE-35NI AND FE-CR-35NI ALLOYS DURING IRRADIATION OR THERMAL AGING SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID FE-NI ALLOYS; MECHANICAL-PROPERTIES; COMPOSITIONAL FLUCTUATIONS; MICROSTRUCTURAL EVOLUTION; PHASE-SEPARATION; INVAR-ALLOYS; RADIATION; HELIUM; TEMPERATURE; DEPENDENCE AB Fe-35Ni and Fe-Cr-35Ni alloys appear to thermally decompose in a spinodal-like but very sluggish manner at temperatures between approximately 400 to 800-degrees-C, with the miscibility gap spanning nickel levels of approximately 30 to 40%. When irradiated with either charged particles or neutrons at these temperatures, the instability is accelerated and the miscibility gap widens to span approximately 25 to 50% Ni, developing very large and temperature-dependent wavelengths. This phenomenon is thought to be the result of the combined action of a natural instability and radiation-induced segregation, cooperating to produce a new form of compositional self-organization. Three experimental methods have been developed to allow a visualization of the decomposition on a large scale. C1 MIT, CAMBRIDGE, MA 02139 USA. WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA. RP GARNER, FA (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 51 TC 20 Z9 20 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 1993 VL 205 BP 411 EP 425 DI 10.1016/0022-3115(93)90105-8 PG 15 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200041 ER PT J AU BELLON, P OKAMOTO, PR SCHUMACHER, G AF BELLON, P OKAMOTO, PR SCHUMACHER, G TI NONEQUILIBRIUM STRUCTURES INDUCED BY ION IRRADIATION IN NI4MO SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID SHORT-RANGE ORDER AB We have studied the stability of equilibrium and metastable ordered phases (called LRO and SRO, respectively) in Ni4Mo during 500 keV Ne or 250 keV He irradiations. Some irradiations were performed in situ, allowing thus to follow the evolution of the samples, which were characterized by transmission electron microscopy (TEM). Dynamical equilibrium phase diagrams are built, by varying the irradiation flux, temperature and dose. At a fixed ion flux, there exists a temperature range were a ''mixed'' ordered state is stabilized, and remains stable up to the maximum doses reached (1.7 dpa). This state, which cannot be obtained by electron irradiation, consists in the coexistence of the two ordered phases at a very fine scale (less-than-or-equal-to 2 nm). Comparison with results already reported after electron irradiation is made, stressing the role played by displacement cascades in our results. Furthermore we observed alignment of dislocation loops along the [001] c-axis of the quadratic LRO phase. C1 ARGONNE NATL LAB, MSD, ARGONNE, IL 60439 USA. HAHN MEITNER INST BERLIN GMBH, W-1000 BERLIN 39, GERMANY. RP CE SACLAY, CEREM, SRMP, F-91191 GIF SUR YVETTE, FRANCE. NR 18 TC 11 Z9 11 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 1993 VL 205 BP 438 EP 444 DI 10.1016/0022-3115(93)90107-A PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200043 ER PT J AU SMALINSKAS, K CHEN, GS HAWORTH, J TAPPIN, DK ROBERTSON, IM KIRK, MA AF SMALINSKAS, K CHEN, GS HAWORTH, J TAPPIN, DK ROBERTSON, IM KIRK, MA TI A STUDY OF THE PROBABILITY OF VACANCY LOOP FORMATION IN NI-CU AND AG-PD ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON THE EVOLUTION OF MICROSTRUCTURE IN METALS DURING IRRADIATION CY SEP 28-OCT 02, 1992 CL CLEVELANDS HOUSE, MUSKOKA, CANADA SP ATOM ENERGY CANADA, ONTARIO HYDRO, CANDU OWNERS GRP HO CLEVELANDS HOUSE ID ENERGETIC DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; DISLOCATION LOOPS AB The molten-zone model for vacancy loop formation from a displacement cascade predicts that the probability of loop formation should scale with the melting temperature. To investigate this Possibility the areal defect density, the loop size, and the vacancy retention factor have been determined in a series of Cu-Ni and Ag-Pd alloys. The irradiations were performed at room temperature with 50 keV Kr+ ions and the resulting damage structure was examined by using transmission electron microscopy. In the Cu-Ni alloy series, the vacancy retention factor decreased with increasing solute content (melting temperature) but not in a simple manner. The behavior in the Cu-Ni system could be predicted when the effect of heat removal through the electronic system on the lifetime of the molten zone was taken into account. In the Ag-Pd alloy the change in the vacancy retention factor followed more closely the change in melting temperature, heat removal through the electronic system appeared to have little effect. C1 ARGONNE NATL LAB,DIV MAT,ARGONNE,IL 60439. RP SMALINSKAS, K (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,1304 W GREEN ST,URBANA,IL 61801, USA. NR 17 TC 2 Z9 2 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 OCT PY 1993 VL 205 BP 483 EP 489 DI 10.1016/0022-3115(93)90113-D PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA MA982 UT WOS:A1993MA98200049 ER PT J AU SETLOW, RB AF SETLOW, RB TI BROOKHAVEN-NATIONAL-LABORATORY AND THE BLIP UPGRADE SO JOURNAL OF NUCLEAR MEDICINE LA English DT Letter RP SETLOW, RB (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 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 OCT PY 1993 VL 34 IS 10 BP 1828 EP 1828 PG 1 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA MA617 UT WOS:A1993MA61700049 PM 8410311 ER PT J AU BETHEL, CAI MURAGESH, D HARRISON, MR MOHANDAS, N RUBIN, ER AF BETHEL, CAI MURAGESH, D HARRISON, MR MOHANDAS, N RUBIN, ER TI FETAL HEMATOPOIETIC STEM-CELL TRANSPLANTATION INTO BETA-THALASSEMIC MICE SO JOURNAL OF PEDIATRIC SURGERY LA English DT Article; Proceedings Paper CT 1992 ANNUAL MEETING OF THE SECTION-ON-SURGERY OF THE AMERICAN-ACADEMY-OF-PEDIATRICS CY OCT 09-11, 1992 CL SAN FRANCISCO, CA SP AMER ACAD PEDIAT, SECT SURG DE BETA-THALASSEMIA; HEMATOPOIETIC STEM CELLS; FETAL LIVER; CHIMERISM ID INUTERO TRANSPLANTATION; MEMBRANE-PROPERTIES; LIVER; DEFORMABILITY C1 UCSF,MED CTR,DEPT SURG,FETAL TREATMENT PROGRAM,585 HSE,3RD & PARNASSUS AVES,SAN FRANCISCO,CA 94131. LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. NR 24 TC 3 Z9 3 U1 0 U2 1 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 SN 0022-3468 J9 J PEDIATR SURG JI J. Pediatr. Surg. PD OCT PY 1993 VL 28 IS 10 BP 1232 EP 1238 DI 10.1016/S0022-3468(05)80304-5 PG 7 WC Pediatrics; Surgery SC Pediatrics; Surgery GA MD716 UT WOS:A1993MD71600003 PM 7903357 ER PT J AU BRANDOW, BH AF BRANDOW, BH TI HIGHLY ANISOTROPIC BUT NODELESS GAP FROM A VALENCE-FLUCTUATION PAIRING MECHANISM SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE GAP ANISOTROPY; VALENCE-FLUCTUATION MECHANISM ID HIGH-TC-SUPERCONDUCTORS; ANDERSON LATTICE MODEL; HIGH-TEMPERATURE SUPERCONDUCTIVITY; COPPER-OXIDE SUPERCONDUCTORS; LIFETIME AB We have refined and quantitatively explored a valence-fluctuation pairing mechanism, the finite-U mechanism introduced by Newns. This can provide an s-like (nodeless) gap. We use an Anderson-lattice Hamiltonian, with realistic parameter values derived from photoemission and BIS data. The Landau-Luttinger quasiparticle spectrum and the pairing interaction are obtained from a many-body variational formalism. Adequate pairing attraction is obtained, together with band narrowing (mass enhancement) and an extremely short coherence length, in reasonable agreement with experiment. These fully self-consistent results were obtained with an isotropic approximation to the band structure of a single CuO2 plane. Now, using a simplified treatment for a MoTe realistic band structure, we find that the gap has strong in-plane anisotropy, although it should probably still remain nodeless. This conclusion is consistent with a variety of data. RP BRANDOW, BH (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 26 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 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1137 EP 1140 DI 10.1016/0022-3697(93)90154-J PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400011 ER PT J AU GULACSI, M FAZEKAS, P AF GULACSI, M FAZEKAS, P TI PHASE-DIAGRAM OF THE ONE-DIMENSIONAL T-J-V MODEL SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE ONE-DIMENSIONAL SYSTEMS; EXTENDED T-J MODEL; VARIATIONAL METHOD; PHASE SEPARATION AB A cluster variational method in used to study the ground state properties of the one-dimensional t - J - V model, where V is the coupling constant of the density-density interaction term. The phase diagram of this extended model is determined for -2.0 less-than-or-equal-to V/J less-than-or-equal to 0.3. From the electron concentration dependence of the ground state energy, we determine the thermodynamic boundary where segregation into an electron-rich, and purely hole phase sets in. For increasing V the phase separation region is strongly diminished while the hole-hole pair formation region is increased. C1 INT CTR THEORET PHYS,I-34100 TRIESTE,ITALY. RES INST SOLID STATE PHYS,H-1525 BUDAPEST 114,HUNGARY. RP GULACSI, M (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 13 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1141 EP 1144 DI 10.1016/0022-3697(93)90155-K PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400012 ER PT J AU COFFEY, D BEDELL, KS AF COFFEY, D BEDELL, KS TI SIMILARITY OF THE LEADING CONTRIBUTIONS TO THE SELF-ENERGY AND THE THERMODYNAMICS IN 2-DIMENSIONAL AND 3-DIMENSIONAL FERMI LIQUIDS SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE 2 DIMENSIONS; FERMI LIQUIDS; THERMODYNAMICS ID HIGH-TEMPERATURE SUPERCONDUCTORS; HUBBARD-MODEL; 2 DIMENSIONS; NORMAL-STATE; BEHAVIOR; DENSITY AB We compare the self-energy and entropy of a two- and three- dimensional Fermi Liquids(FLs) using a model with a contact interaction between fermions. For a two-dimensional(2D) FL we find that there are T2 contributions to the entropy from interactions separate from those due to the collective modes. These T2 contributions arise from non-analytic corrections, to the real part of the self-energy and are analogous to T3lnT contributions present in the entropy of a three-dimensional(3D) FL. The difference between the 2D and 3D results arises solely from the different phase space factors. RP COFFEY, D (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1145 EP 1147 DI 10.1016/0022-3697(93)90156-L PG 3 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400013 ER PT J AU GULACSI, M BEDELL, KS AF GULACSI, M BEDELL, KS TI SINGLE-PARTICLE GREEN-FUNCTION OF THE 1D HUBBARD-MODEL SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE ONE-DIMENSIONAL SYSTEMS; BOSONIZATION; METAL-INSULATOR TRANSITION ID DIMENSIONAL ELECTRON-GAS; GROUND-STATE; EXPONENTS; SPECTRUM; LATTICE AB For the one-dimensional Hubbard model we extended the bosonization technique, away from half filling, in such a way that a general formula is obtained for the zero temperature equal-time single-particle Green function with validity over the whole doping range. With our method we can calculate, for the first time, the one-body Green function in both the Tomonaga-Luttinger and Luther-Emery universality classes, to characterize the crossover between these two behaviors and thus, to describe the Mott transition. The method also gives a tool to determine the coefficients of the correlation functions which cannot be determined with previously used methods. RP GULACSI, M (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 19 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1149 EP 1152 DI 10.1016/0022-3697(93)90157-M PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400014 ER PT J AU NORMAN, MR AF NORMAN, MR TI AFTER 7 YEARS, WHERES THE CONSENSUS SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE THEORY; HIGH TEMPERATURE SUPERCONDUCTORS AB A summary of the theoretical part of the conference is given. RP NORMAN, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Norman, Michael/C-3644-2013 NR 0 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1165 EP 1168 DI 10.1016/0022-3697(93)90161-J PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400018 ER PT J AU SHEN, ZX DESSAU, DS WELLS, BO KING, DM AF SHEN, ZX DESSAU, DS WELLS, BO KING, DM TI RECENT RESULTS FROM BI2SR2CACU2O8 AND ND2-XCEXCUO4 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE HIGH-TEMPERATURE SUPERCONDUCTOR; PHOTOEMISSION; FERMI SURFACE; SUPERCONDUCTING GAP ID HIGH-TEMPERATURE SUPERCONDUCTORS; CA-CU-O; PHOTOELECTRON-SPECTROSCOPY; ELECTRONIC-STRUCTURE; PHOTOEMISSION; GAP AB We review recent angle-resolved photoemission data from Bi2212 and NCCO. We concentrate on the data revealing the charge excitations near the Fermi level, the shape of the Fermi surfaces and the anisotropic nature of the superconducting gap. C1 STANFORD UNIV,STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94305. RP SHEN, ZX (reprint author), STANFORD UNIV,DEPT APPL PHYS,STANFORD ELECTR LAB,MCCULLOUGH BLDG,STANFORD,CA 94305, USA. NR 20 TC 11 Z9 11 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1169 EP 1176 DI 10.1016/0022-3697(93)90162-K PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400019 ER PT J AU GU, C VEAL, BW LIU, R DING, H PAULIKAS, AP CAMPUZANO, JC KOSTIC, P WHEELER, RW ZHANG, H AF GU, C VEAL, BW LIU, R DING, H PAULIKAS, AP CAMPUZANO, JC KOSTIC, P WHEELER, RW ZHANG, H TI PHOTOEMISSION-STUDIES OF ZN, CO, AND GD SUBSTITUTED YBA2CU3O7-DELTA SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE PHOTOEMISSION; SUBSTITUTION; OXYGEN STOICHIOMETRY; ELECTRONIC STRUCTURE ID FERMI-SURFACE TOPOLOGY; ELECTRONIC-STRUCTURE; HALL ANGLE; YBA2CU3O6.9; BANDS AB Zn and Co substitute for Cu in YBa2Cu3O7-delta at the plane and chain sites, respectively. We report a high resolution angle-resolved photoemission study on Zn and Co substituted YBa2Cu3O7-delta single crystals to determine the effects on electronic structure. The valence states near E(F) along GAMMA-S are virtually unaffected by the substitutions for samples that are superconducting. However, the spectral weight near E(F) disappears for a higher Co-doped, non-superconducting crystal. The results are compared with earlier studies on pure YBa2Cu3O7-delta with controlled oxygen stoichiometry. Measurement on Gd-123 crystals with reduced oxygen stoichiometries show gradual reduction of spectral weight for a band along GAMMA-Y(X), in contrast to the results for the bands along GAMMA-S. The differences are probably due to a different admix of Cu-O chain and plane characters in these bands. We also measured Gd 4f resonance spectra, which exhibit complex structure, indicating the presence of Gd atoms in chemically inequivalent (probably bulk and near surface) sites. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV ILLINOIS,CHICAGO,IL 60680. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP GU, C (reprint author), ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439, USA. RI Campuzano, Juan Carlos/G-4358-2012; OI Ding, Hong/0000-0003-4422-9248 NR 21 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1177 EP 1184 DI 10.1016/0022-3697(93)90163-L PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400020 ER PT J AU BANSIL, A LINDROOS, M GOFRON, K CAMPUZANO, JC AF BANSIL, A LINDROOS, M GOFRON, K CAMPUZANO, JC TI ANGLE-RESOLVED PHOTOEMISSION FROM YBA2CU3O7 - SIGNATURE OF CUO2 PLANE BANDS SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE HIGH-T(C) SUPERCONDUCTORS; ANGLE RESOLVED PHOTOEMISSION; YBA2CU3O7 ID FERMI-SURFACE; ELECTRONIC-STRUCTURE; DISPERSION; SPECTRA; DENSITY; ALLOYS; GAP AB We have carried out polarization dependent first principles calculations of the angle-resolved photoemission (ARPES) spectra within the local-density approximation (LDA) based band theory framework for the YBa2Cu3O7(001)-surface for k(parallel-to)-values along the GAMMAS line for all six possible ideal terminations of the lattice, together with parallel ARPES measurements. The theoretically predicted intensity and polarization dependence of the spectral feature arising from the CuO2 Plane bands near the Fermi energy is in remarkable overall accord with the measurements, giving confidence in the interpretation of the experimental data as being representative of the-bulk CuO2 bands. These results suggest that the LDA-based wave-functions implicit in the theory reasonably describe the physical situation at least near the Fermi energy, some renormalization of the quasi-particle spectrum notwithstanding. The question of surface termination is discussed; the present study favors the Y123(001)-surface to involve BaO topmost layer followed by the CuO2 plane layer. C1 TAMPERE UNIV TECHNOL,SF-33101 TAMPERE,FINLAND. ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV ILLINOIS,CHICAGO,IL 60680. RP BANSIL, A (reprint author), NORTHEASTERN UNIV,DEPT PHYS,BOSTON,MA 02115, USA. RI Campuzano, Juan Carlos/G-4358-2012 NR 28 TC 21 Z9 21 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1185 EP 1192 DI 10.1016/0022-3697(93)90164-M PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400021 ER PT J AU GOFRON, K CAMPUZANO, JC DING, H GU, C LIU, R DABROWSKI, B VEAL, BW CRAMER, W JENNINGS, G AF GOFRON, K CAMPUZANO, JC DING, H GU, C LIU, R DABROWSKI, B VEAL, BW CRAMER, W JENNINGS, G TI OCCURRENCE OF VANHOVE SINGULARITIES IN YBA2CU4O8 AND YBA2CU3O6.9 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE HIGH T(C) SUPERCONDUCTORS; VANHOVE SINGULARITIES; PHOTOEMISSION; ARPES; FERMI SURFACE ID HIGH-TC SUPERCONDUCTORS; LIFETIME; DENSITY; STATES AB We report seeing a saddle point in the energy band, known as a van Hove singularity. We measure an exact position of the singularity in both YBa2Cu4O8 (Y124) and YBa2Cu3O6.9 (Y123). In Y123 the van Hove singularity is at binding energy of less then 10 meV, closer ot E(F), than in Y124, which has a singularity at 19 meV. The singularity has and extended character along the GAMMA-Y direction. Another clearly resolved band exhibits a saddle point singularity at binding energy of 115 meV. Similar singularities are observed in the vicinity of the X point, extended along the GAMMA-X direction. In order to study these features the energy resolution of the system was improved to better than 10 meV. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP GOFRON, K (reprint author), UNIV ILLINOIS,DEPT PHYS,POB 4348,CHICAGO,IL 60680, USA. RI Campuzano, Juan Carlos/G-4358-2012; OI Ding, Hong/0000-0003-4422-9248 NR 26 TC 120 Z9 120 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1193 EP 1198 DI 10.1016/0022-3697(93)90165-N PG 6 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400022 ER PT J AU GUO, JH WASSDAHL, N SKYTT, P BUTORIN, S MA, Y NORDGREN, J AF GUO, JH WASSDAHL, N SKYTT, P BUTORIN, S MA, Y NORDGREN, J TI ELECTRONIC-STRUCTURE OF LA2-XSRXCUO4 STUDIED BY RESONANT SOFT-X-RAY FLUORESCENCE SPECTROSCOPY SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE SOFT X-RAY FLUORESCENCE; TUNABLE MONOCHROMATIZED SYNCHROTRON RADIATION; HIGH T(C) SUPERCONDUCTOR; LA2-XSRXCUO4 ID HIGH-TC SUPERCONDUCTORS; EMISSION-SPECTROSCOPY; BAND-STRUCTURE; SPECTRA; STATES; DESIGN; HOLES AB The O Kalpha X-ray fluorescence of La2-xSrxCuO4 have been recorded using tunable and high-resolution monochromatized synchrotron radiation excitation. A strong variation in the shape of the O Kalpha emission spectra depending on incidence photon energy is observed. The lineshape change results from varying of in-plane and apical oxygen contributions into the emission line. The X-ray emission bands which reflect the local 2p density of states as to the two inequivalent oxygen sites have been distinguished. C1 PACIFIC NW LAB, MSRC, RICHLAND, WA 99352 USA. RP GUO, JH (reprint author), UNIV UPPSALA, DEPT PHYS, BOX 530, S-75121 UPPSALA, SWEDEN. NR 18 TC 11 Z9 11 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1203 EP 1206 DI 10.1016/0022-3697(93)90167-P PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400024 ER PT J AU STERNE, PA HOWELL, RH FLUSS, MJ KAISER, JH KITAZAWA, K KOJIMA, H AF STERNE, PA HOWELL, RH FLUSS, MJ KAISER, JH KITAZAWA, K KOJIMA, H TI POSITRON-ANNIHILATION STUDY OF SR DOPING IN LA2-XSRXCUO4 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE LA2-XSRXCUO4; POSITRON ANNIHILATION; 2D-ACAR; FERMI SURFACE; SR DOPING; MOMENTUM DENSITIES ID FERMI-SURFACE; YBA2CU3O7-DELTA; BANDS AB We present a combined experimental and theoretical study of the effects of Sr doping on the electronic structure of La2-xSrxCuO4. Electron-positron momentum distributions have been measured to high statistical precision (> 4 x 10(8) counts) at room temperature for samples with Sr concentrations of x = 0.0, 0.1, 0.13 and 0.2. Analysis of all four spectra reveal strong features due to electron-positron wavefunction overlap, in quantitative agreement with theoretical calculations. The Sr doped samples show discontinuities consistent with the presence of a Fermi surface. The form and position of these features are in general agreement with the predictions of band theory. Correspondence between theory and experiment, as well as some differences, are revealed by a detailed study of the changes in electron-positron momentum density with increasing Sr doping. C1 UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV TEXAS,ARLINGTON,TX 76019. UNIV TOKYO,TOKYO 113,JAPAN. YAMANASHI UNIV,KOFU,YAMANASHI 400,JAPAN. RP STERNE, PA (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 13 TC 14 Z9 14 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1231 EP 1238 DI 10.1016/0022-3697(93)90173-O PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400030 ER PT J AU SMEDSKJAER, LC PANKALUOTO, R BANSIL, A MIJNARENDS, PE AF SMEDSKJAER, LC PANKALUOTO, R BANSIL, A MIJNARENDS, PE TI FERMIOLOGY OF YBA2CU3O6.9 - POSITRON-ANNIHILATION STUDIES SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE HIGH-T(C) SUPERCONDUCTORS; FERMI SURFACE; YBA2CU3O7 ID MOMENTUM DENSITY; ELECTRONIC-STRUCTURE; METALLIC YBA2CU3O7-X; 2D ACAR; SURFACE AB We present and discuss two-dimensional angular correlation of annihilation radiation (2D-ACAR) positron spectra of YBa2Cu3O6.9 (Y123) metallic single crystals. The c-axis as well as the a-axis projected spectra are considered with focus on delineating the Fermiology of Y123. The results are interpreted with the help of the corresponding predictions of the conventional band theory based model employing the local density approximation. The computed signature of the Cu-O chain related Fermi surface is in good overall accord with the 2D-ACAR measurements. C1 NORTHEASTERN UNIV,DEPT PHYS,BOSTON,MA 02115. DELFT UNIV TECHNOL,INST INTERFAC REACTOR,2629 JB DELFT,NETHERLANDS. TAMPERE UNIV TECHNOL,DEPT PHYS,SF-33101 TAMPERE 10,FINLAND. RP SMEDSKJAER, LC (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 32 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1239 EP 1245 DI 10.1016/0022-3697(93)90174-P PG 7 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400031 ER PT J AU GOODRICH, RG GRIENIER, C HALL, D LACERDA, A HAANAPPEL, EG RICKEL, D NORTHINGTON, T SCHWARZ, R MUELLER, FM KOELLING, DD VUILLEMIN, J VANBOCKSTAL, L NORTON, ML LOWNDES, DH AF GOODRICH, RG GRIENIER, C HALL, D LACERDA, A HAANAPPEL, EG RICKEL, D NORTHINGTON, T SCHWARZ, R MUELLER, FM KOELLING, DD VUILLEMIN, J VANBOCKSTAL, L NORTON, ML LOWNDES, DH TI DE-HAAS-VAN-ALPHEN MEASUREMENTS IN BA0.6K0.4BIO3 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB ID FERMI-SURFACE; 2H-NBSE2 AB dHvA measurements have been made on the 32 Kelvin cubic superconductor Ba0.6K0.4BiO3 (BKBO) using a new and non-destructive 50 Tesla pulsed field magnet at the NHMFL at Los Alamos, as well as in an 18 T superconducting magnet at Louisiana State University. Data were taken with the magnetic field aligned along the [001] crystallographic direction. Sample temperatures were varied from 1.5 to 3.9 Kelvin. The pulsed fields employed were high enough to drive the system well into the normal state. An analysis of these results showed that the frequencies of the observed dHvA oscillations arose from a several Fermi surface sheets. One cross-section was nearly identical with that predicted by a new LDA band calculation. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. CATHOLIC UNIV LEUVEN,DEPT NAT,LAGE TEMP HOGE VELDENFYS LAB,B-3000 LOUVAIN,BELGIUM. MARSHALL UNIV,HUNTINGTON,WV 25701. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP GOODRICH, RG (reprint author), LOUISIANA STATE UNIV,DEPT PHYS,BATON ROUGE,LA 70803, USA. NR 12 TC 30 Z9 30 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1251 EP 1258 DI 10.1016/0022-3697(93)90176-R PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400033 ER PT J AU HAANAPPEL, EG JOSS, W WYDER, P ASKENAZY, S MUELLER, FM TRUBENBACH, K MATTAUSCH, H SIMON, A OSOFSKY, M AF HAANAPPEL, EG JOSS, W WYDER, P ASKENAZY, S MUELLER, FM TRUBENBACH, K MATTAUSCH, H SIMON, A OSOFSKY, M TI THE DE-HAAS-VAN-ALPHEN EFFECT IN YBA2CU3O7-DELTA SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB ID MAGNETIC-FIELDS; FERMI-SURFACE; YBA2CU3O6.97 C1 MAX PLANCK INST FESTKORPERFORSCH,HOCHFELD MAGNETLAB,BP 166,F-38042 GRENOBLE 9,FRANCE. COMPLEXE SCI RANGUEIL,SERV CHAMPS MAGNET PULSES,F-31077 TOULOUSE,FRANCE. LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. MAX PLANCK INST FESTKORPERFORSCH,W-7000 STUTTGART,GERMANY. USN,RES LAB,WASHINGTON,DC 20375. NR 20 TC 14 Z9 14 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1261 EP 1267 DI 10.1016/0022-3697(93)90178-T PG 7 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400035 ER PT J AU COOPER, SL NYHUS, P REZNIK, D KLEIN, MV LEE, WC GINSBERG, DM VEAL, BW PAULIKAS, AP AF COOPER, SL NYHUS, P REZNIK, D KLEIN, MV LEE, WC GINSBERG, DM VEAL, BW PAULIKAS, AP TI INTER-BILAYER CHARGE DYNAMICS IN YBA2CU3O6+X SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE INFRARED REFLECTIVITY; RAMAN SCATTERING; C-AXIS CHARGE TRANSPORT ID SINGLE-CRYSTAL; OXIDE SUPERCONDUCTORS; CUO2 PLANES; RESISTIVITY; ANISOTROPY; CONDUCTIVITY AB We present optical reflectivity and Raman scattering studies of YBa2Cu3O6+x as a function of doping using c-axis polarized light. The c-axis optical response of YBa2Cu3O7 is characterized by a Drude-like conductivity and an electronic Raman continuum, indicating a weak coupling between adjacent CuO2 bilayers which is mediated by the CuO chains. With reduced doping, the c-axis Drude and continuum responses rapidly decrease, revealing a strong sensitivity of the inter-bilayer coupling strength to the removal of oxygen from the chain sites. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP COOPER, SL (reprint author), UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1307 EP 1314 DI 10.1016/0022-3697(93)90184-S PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400041 ER PT J AU MILLER, D RICHARDS, PL NICOL, EJ HELLMAN, ES HARTFORD, EH PLATT, CE SCHWEINFURTH, RA VANHARLINGEN, DJ AMANO, J AF MILLER, D RICHARDS, PL NICOL, EJ HELLMAN, ES HARTFORD, EH PLATT, CE SCHWEINFURTH, RA VANHARLINGEN, DJ AMANO, J TI DIRECT SUBMILLIMETER ABSORPTIVITY MEASUREMENTS ON EPITAXIAL BA1-XKXBIO3 FILMS AT 2K SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE HIGH TEMPERATURE SUPERCONDUCTIVITY; THIN FILMS; INFRARED SPECTROSCOPY; BKBO ID SUPERCONDUCTING BA1-XKXBIO3; ENERGY-GAP; THIN-FILMS; RESIDUAL LOSSES; CU-O; TRANSITION; MICROWAVE AB We have used a bolometric technique to obtain accurate low temperature loss data for epitaxial thin films of Ba0.6K0.4BiO3 from 30 cm-1 to 700 cm-1. These films were grown on MgO and SrTiO3 substrates by MBE, off-axis sputtering and laser deposition techniques. All films show a strong absorption onset near the BCS tunneling gap of 3.5k(B)T(C). We have analyzed these data using a Kramers-Kronig transformation and have corrected for finite film thickness effects. Our results indicate that the absorption onset is consistent with a superconducting energy gap. Comparison is made with predictions based on strong coupling Eliashberg theory using alpha2F(omega) spectra obtained from the literature. While we are able to fit the overall measured absorptivity, we are unable to fit the structure observed in our data. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. AT&T BELL LABS,MURRAY HILL,NJ 07974. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. HEWLETT PACKARD CORP,PALO ALTO,CA 94303. UNIV ILLINOIS,SCI & TECHNOL CTR SUPERCOND,URBANA,IL 61801. RP MILLER, D (reprint author), LAWRENCE BERKELEY LAB,DIV MED,BERKELEY,CA 94720, USA. OI Hellman, Eric/0000-0002-9085-5007 NR 19 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1323 EP 1326 DI 10.1016/0022-3697(93)90186-U PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400043 ER PT J AU COFFEY, D AF COFFEY, D TI EFFECT OF SPONTANEOUS DECAY OF SUPERCONDUCTOR QUASI-PARTICLES IN THE TUNNELING DENSITY-OF-STATES SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE SUPERCONDUCTIVITY; TUNNELING; QUASI-PARTICLES ID BI2SR2CACU2O8; ANISOTROPY AB Superconductivity has been successfully described with either the Landau-Ginzburg theory of second order phase transitions or with strong-coupling versions of the original BCS theory for almost fifty years. Recent tunnelling and photoemission data on the cuprate oxide superconductors may now provide evidence of corrections to the mean field approximation. It has been shown by Zasadzinski et al.a[1992] that there is a dip at eV congruent-to 3DELTA0 in the SIS tunneling conductance, which is the derivative of the current across a superconductor-insulator-superconductor junction with respect to the applied voltage, for a set of cuprate superconductors whose T(c)'s range from 5.5K to 100K. Recently L. Coffey and I[Coffey and Coffey 1993] proposed an explanation of this feature in terms of the spontaneous decay of mean field quasiparticles. We showed that corrections to the mean field approximation for a superconductor lead to different frequency thresholds for spontaneous quasiparticle decay with different superconductor order parameter symmetries. These effects lead to features in the superconductor density of states and in the SIS tunneling conductance and provide experimental evidence of d-wave symmetry for the superconductor order parameter in the cuprates. I discuss this model and also evidence of quasiparticle decay in ARPES data on Bi2Sr2CaCu2O8. RP COFFEY, D (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 24 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1369 EP 1376 DI 10.1016/0022-3697(93)90195-W PG 8 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400052 ER PT J AU REYES, AP HAMMEL, PC AHRENS, ET THOMPSON, JD CANFIELD, PC FISK, Z SCHIRBER, JE AF REYES, AP HAMMEL, PC AHRENS, ET THOMPSON, JD CANFIELD, PC FISK, Z SCHIRBER, JE TI PHASE-SEPARATION AND SUPERCONDUCTIVITY IN LA2CUO4+DELTA - EFFECTS OF OXYGEN DIFFUSION SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE NQR; NMR; HIGH-T(C) SUPERCONDUCTIVITY; LOCAL STRUCTURES; PHASE SEPARATION; OXYGEN DIFFUSION; LA2CUO4 ID NEUTRON-DIFFRACTION; LA-139 NMR; NQR; TC; TEMPERATURE; BEHAVIOR AB In oxygen-annealed LaCuO4+delta (delta approximately 0.03), bulk magnetization measurements show an increase of approximately 4K in the superconducting T(c) when the sample is cooled slowly through a narrow temperature range near 195K. At this temperature, La-139 NQR spectra exhibit a concomitant appearance of an anomalous feature associated with the metallic phase whose spectral weight increases with cooling rate. The data suggests a distribution of local structures and annealing-dependent volume fraction in this part of the sample. Interpretation of these results in terms of oxygen diffusion in a phase separated material is considered and a picture consistent with the observed changes in T(c) is obtained. The activation energy of oxygen diffusion derived from the model, Q approximately 0.25 eV, is in the same order of magnitude as the results obtained in La2-xSrxCuO4-y. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP REYES, AP (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Canfield, Paul/H-2698-2014; Hammel, P Chris/O-4845-2014 OI Hammel, P Chris/0000-0002-4138-4798 NR 33 TC 14 Z9 14 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1393 EP 1402 DI 10.1016/0022-3697(93)90199-2 PG 10 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400056 ER PT J AU KWEI, GH SCHIRBER, JE MOROSIN, B VENTURINI, EL VOIGT, JA GOLDSTONE, JA LAWSON, AC AF KWEI, GH SCHIRBER, JE MOROSIN, B VENTURINI, EL VOIGT, JA GOLDSTONE, JA LAWSON, AC TI PHASE-SEPARATION AND SUPERCONDUCTIVITY IN SUPEROXYGENATED LA2-XSRXCUO4+DELTA SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB ID LA2CUO4.032; SEARCH AB La2-xSrxCuO4+delta with x = 0.01, 0.025, 0.050, 0.10 and 0.16 and with excess oxygen delta incorporated using high-pressure O2 anneals has been examined using neutron diffraction data. Various models were fit by Rietveld least-squares refinement, with the maximum amount of delta being only of the order of 20 times the standard deviation. Delta is largest for x near 0, is zero for x = 0.10 and is intermediate for x = 0.16. Only the sample with x - 0.01 shows distinct phase separation into a nearly stoichiometric phase with delta almost-equal-to 0 and an oxygen-rich superconducting phase as the temperature is lowered. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP KWEI, GH (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544, USA. NR 10 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 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1403 EP 1406 DI 10.1016/0022-3697(93)90200-B PG 4 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400057 ER PT J AU SCHIRBER, JE OVERMYER, DL BAYLESS, WR ROSSEINSKY, MJ MURPHY, DW ZHU, Q ZHOU, O KNIAZ, K FISCHER, JE AF SCHIRBER, JE OVERMYER, DL BAYLESS, WR ROSSEINSKY, MJ MURPHY, DW ZHU, Q ZHOU, O KNIAZ, K FISCHER, JE TI FULLERENE SUPERCONDUCTORS - PHASE-STABILITY AND ANOMALOUSLY LOW T(C)S IN SOME TERNARY COMPOUNDS SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB DE FULLERENES; SUPERCONDUCTIVITY; INTERCALATION; RF IMPEDANCE; X-RAY DIFFRACTION; HIGH PRESSURE ID TRANSITION-TEMPERATURE; PRESSURE-DEPENDENCE; C-60; LATTICE AB AC impedance and x-ray diffraction measurements versus temperature and pressure on several ternary fullerene intercalation compounds are reported. The results support our previously established empirical correlation between superconducting onset temperature and 300K fcc lattice constant. Compounds which do not follow this correlation either phase separate or are otherwise unstable at low T and/or high P. C1 UNIV OXFORD,OXFORD OX1 3QR,ENGLAND. AT&T BELL LABS,MURRAY HILL,NJ 07974. UNIV PENN,PHILADELPHIA,PA 19104. RP SCHIRBER, JE (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87110, USA. NR 15 TC 16 Z9 16 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1427 EP 1431 DI 10.1016/0022-3697(93)90203-4 PG 5 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400060 ER PT J AU FISK, Z AF FISK, Z TI THE FOLKLORE OF SUPERCONDUCTIVITY SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT Conference on Spectroscopies in Novel Superconductors CY MAR 17-19, 1993 CL SANTA FE, NM SP LOS ALAMOS NATL LAB, ARGONNE NATL LAB RP FISK, Z (reprint author), LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP 1469 EP 1470 DI 10.1016/0022-3697(93)90210-I PG 2 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400067 ER PT J AU MUELLER, F BANSIL, A ARKO, A AF MUELLER, F BANSIL, A ARKO, A TI SPECTROSCOPIES IN NOVEL SUPERCONDUCTORS - PREFACE SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Editorial Material C1 NORTHEASTERN UNIV,BOSTON,MA 02115. RP MUELLER, F (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 1993 VL 54 IS 10 BP R9 EP R9 DI 10.1016/0022-3697(93)90142-E PG 1 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA MN594 UT WOS:A1993MN59400001 ER PT J AU LEVIN, E AF LEVIN, E TI LOW-X(B) NEWS FOR EXPERTS SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Review ID HEAVY-QUARK PRODUCTION; PARTON SATURATION; BEHAVIOR; MODEL; QCD AB This is a status report on the recent theoretical development in the region of small x(B) in deep-inelastic scattering. C1 ST PETERSBURG NUCL PHYS INST,GATCHINA 188350,RUSSIA. RP LEVIN, E (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 30 TC 7 Z9 7 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 OCT PY 1993 VL 19 IS 10 BP 1453 EP 1462 DI 10.1088/0954-3899/19/10/003 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA MF208 UT WOS:A1993MF20800004 ER PT J AU MAGILL, SR AF MAGILL, SR TI ZEUS RESULTS FROM THE 1ST YEAR - DIS CROSS-SECTION AND HADRONIC FINAL-STATES SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article ID QCD AB The first year of operation of the HERA electron-proton collider has resulted in deep inelastic scattering (DIS) physics results from both the H1 and ZEUS experiments. Reported here are results from the ZEUS collaboration on the measurement of the DIS neutral-current cross section, which has been made at higher Q2 and lower x(Bj) than previously reported from fixed-target experiments. The final-state hadronic energy flow has been studied, and comparison with various QCD Monte Carlo models shows that QCD radiation has a strong influence on its characteristics. The observation of multi-jet production in Dis neutral-current events is also reported here. RP MAGILL, SR (reprint author), ARGONNE NATL LAB,DIV HEP,BLDG 362,ARGONNE,IL 60439, USA. NR 23 TC 4 Z9 4 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 OCT PY 1993 VL 19 IS 10 BP 1535 EP 1547 DI 10.1088/0954-3899/19/10/010 PG 13 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA MF208 UT WOS:A1993MF20800011 ER PT J AU LAENEN, E LEVIN, E AF LAENEN, E LEVIN, E TI A NOTE ON HOT-SPOT HUNTING IN DEEP-INELASTIC SCATTERING SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Note ID REGION; HERA AB We consider the inclusive cross section for jet production with large transverse momentum in deep-inelastic scattering. This process has been proposed as a probe of small-x physics, particularly the measurement of 'hot spots' inside the proton. We present a numerical calculation of this process, taking into account a larger phase space. The theoretical reliability, as well as phenomenological uncertainties in the calculation are discussed. RP FERMILAB NATL ACCELERATOR LAB, POB 500, MS 106, BATAVIA, IL 60510 USA. NR 20 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 EI 1361-6471 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD OCT PY 1993 VL 19 IS 10 BP 1582 EP 1586 DI 10.1088/0954-3899/19/10/014 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA MF208 UT WOS:A1993MF20800015 ER PT J AU LYON, WS AF LYON, WS TI RAYS-ING AND LOWERING FEARS SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-LETTERS LA English DT Article RP LYON, WS (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU AKADEMIAI KIADO PI BUDAPEST PA PO BOX 245, H-1519 BUDAPEST, HUNGARY SN 0236-5731 J9 J RADIOAN NUCL CH LE JI J. Radioanal. Nucl. Chem.-Lett. PD OCT 1 PY 1993 VL 176 IS 4 BP 267 EP 271 DI 10.1007/BF02163491 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA MB184 UT WOS:A1993MB18400001 ER PT J AU KOLLAR, LP SPRINGER, GS SPINGARN, J MCCOLSKEY, JD AF KOLLAR, LP SPRINGER, GS SPINGARN, J MCCOLSKEY, JD TI COMPRESSIVE STRENGTH OF AXIALLY LOADED COMPOSITE CYLINDERS SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article AB Tests were performed to measure the failure loads of axially compressed glass-fiber-reinforced and graphite-fiber-reinforced composite cylinders. The data were compared with the results of a previous model, which was based on a three-dimensional stress analysis and the Tsai-Wu quadratic first-ply failure criterion. This model predicted the failure loads for glass-fiber-reinforced composites with good accuracy, but less accurately for failure loads of graphite-epoxy composites. C1 STANFORD UNIV,DEPT AERONAUT & ASTRONAUT,STANFORD,CA 94305. SANDIA NATL LABS,LIVERMORE,CA 94551. NATL INST STAND & TECHNOL,BOULDER,CO 80303. RI Kollar, Laszlo/B-6908-2009 OI Kollar, Laszlo/0000-0001-9313-2296 NR 2 TC 0 Z9 0 U1 0 U2 1 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 OCT PY 1993 VL 12 IS 10 BP 1070 EP 1080 DI 10.1177/073168449301201004 PG 11 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA LY511 UT WOS:A1993LY51100004 ER PT J AU DRUMHELLER, DS AF DRUMHELLER, DS TI ATTENUATION OF SOUND-WAVES IN DRILL STRINGS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB During drilling of deep wells, digital data are often transmitted from sensors located near the drill bit to the surface. Development of a new communication system with increased data capacity is of paramount importance to the drilling industry. Since steel drill strings are used, transmission of these data by elastic carrier waves traveling within the drill pipe is possible, but the potential communication range is uncertain. The problem is complicated by the presence of heavy-threaded tool joints every 10 m, which form a periodic structure and produce classical patterns of passbands and stop bands in the wave spectra. In this article, field measurements of the attenuation characteristics of a drill string in the Long Valley Scientific Well in Mammoth Lakes, California are presented. Wave propagation distances approach 2 km. A theoretical model is discussed which predicts the location, width, and attenuation of the passbands. Mode conversion between extensional and bending waves, and spurious reflections due to deviations in the periodic spacings of the tool joints are believed to be the sources of this attenuation. It is estimated that attenuation levels can be dramatically reduced by rearranging the individual pipes in the drill string according to length. RP DRUMHELLER, DS (reprint author), SANDIA NATL LABS,GEOTHERMAL RES DEPT,ALBUQUERQUE,NM 87185, USA. NR 7 TC 18 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD OCT PY 1993 VL 94 IS 4 BP 2387 EP 2396 DI 10.1121/1.407458 PG 10 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA MB552 UT WOS:A1993MB55200047 ER PT J AU SU, P VIRKAR, AV HUBBARD, CR CAVIN, OB PORTER, WD AF SU, P VIRKAR, AV HUBBARD, CR CAVIN, OB PORTER, WD TI CUBIC-TO-TETRAGONAL DISPLACIVE TRANSFORMATION IN GD2O3-BI2O3 CERAMICS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID OXIDE ION CONDUCTION; SINTERED OXIDES; STABILITY AB Gd2O3-doped Bi2O3 polycrystalline ceramics containing between 2 and 7 mol% Gd2O3 were fabricated by pressureless sintering Powder compacts. The as-sintered samples were tetragonal at room temperature. High-temperature X-ray diffraction (XRD) traces showed that the samples were cubic at elevated temperatures and transformed into the tetragonal polymorph during cooling. On the basis of conductivity measurements as a function of temperature and differential scanning calorimetry (DSC), the cubic --> tetragonal as well as tetragonal --> cubic transition temperatures were determined as a function of Gd2O3 concentration. The cubic --> tetragonal transformation appears to be a displacive transformation. It was observed that additions of ZrO2 as a dopant, which is known to suppress cation interdiffusion in rare-earth oxide-Bi2O3 systems, did not suppress the transition, consistent with it being a displacive transition. Annealing of samples at temperatures less-than-or-equal-to 660-degrees-C for several hundred hours led to decomposition into a mixture of monoclinic and rhombohedral phases. This shows that the tetragonal polymorph is a metastable phase. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP SU, P (reprint author), UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112, USA. NR 14 TC 10 Z9 10 U1 1 U2 3 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 OCT PY 1993 VL 76 IS 10 BP 2513 EP 2520 DI 10.1111/j.1151-2916.1993.tb03974.x PG 8 WC Materials Science, Ceramics SC Materials Science GA MC308 UT WOS:A1993MC30800014 ER PT J AU MICHALSKE, TA BUNKER, BC AF MICHALSKE, TA BUNKER, BC TI A CHEMICAL-KINETICS MODEL FOR GLASS FRACTURE SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID VITREOUS-SILICA; STRESS-CORROSION; CRACK-GROWTH; DISSOLUTION; FATIGUE; DEFECTS AB We utilize a chemical-kinetics-based model to describe the rate of crack extension in vitreous silica as a function of the applied stress and the presence of reactive species. Our approach builds upon previous fracture models that treat the atomic bond rupture process at the crack tip as a stress-enhanced hydrolysis reaction. We derive the stress dependence for siloxane hydrolysis from measurements of hydrolysis rates for strained silicate ring structures. The stress dependence determined for siloxane hydrolysis yields an activation volume of 2.0 cm3/mol, which is in good agreement with the stress dependence determined for silicate glass fracture. This result supports previous fracture models that are based on absolute reaction rate theory and predicts an exponential dependence of crack extension rate on applied stress intensity. RP MICHALSKE, TA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 33 TC 61 Z9 61 U1 0 U2 17 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 OCT PY 1993 VL 76 IS 10 BP 2613 EP 2618 DI 10.1111/j.1151-2916.1993.tb03989.x PG 6 WC Materials Science, Ceramics SC Materials Science GA MC308 UT WOS:A1993MC30800029 ER PT J AU CAMERON, D HEMBERGER, PH ALARID, JE LEIBMAN, CP WILLIAMS, JD AF CAMERON, D HEMBERGER, PH ALARID, JE LEIBMAN, CP WILLIAMS, JD TI THE EFFECTS OF AIR AND HELIUM ON THE PERFORMANCE OF THE ION-TRAP DETECTOR WHEN USED FOR REAL-TIME MONITORING OF SOME ATMOSPHERIC POLLUTANTS SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID PROCESS ANALYTICAL-CHEMISTRY; ORGANIC-COMPOUNDS; MASS-SPECTROMETRY; HAZARDOUS-WASTE; VOLATILE; IONIZATION; SITES AB The feasibility of using an ion trap detector for real-time monitoring of volatile organic compounds in atmospheric samples is demonstrated. Detection limits in the low part-per-million to low part-per-billion ranges are achieved with an operating dynamic range of at least 5 orders of magnitude. Sample introduction through semipermeable membranes and molecular leak valves was evaluated. The membrane introduction method provided detection limit enhancements of 10-300 times over the molecular leak method. The effects of partial pressure from air and helium buffer gas were studied, and it was determined that, for optimum amounts of air, the helium buffer gas had no apparent effect on sensitivity or resolution. Air acts as the buffer gas to enhance ion signals by collisionally damping ion motion. The enhancement of molecular ion abundance at high partial pressures of air is postulated to be due to charge exchange and possibly collisional stabilization reactions. C1 LOS ALAMOS NATL LAB,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87544. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. NR 47 TC 17 Z9 17 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD OCT PY 1993 VL 4 IS 10 BP 774 EP 781 DI 10.1016/1044-0305(93)80034-V PG 8 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA LZ488 UT WOS:A1993LZ48800003 PM 24227461 ER PT J AU WILLIAMS, JD COOKS, RG SYKA, JEP HEMBERGER, PH NOGAR, NS AF WILLIAMS, JD COOKS, RG SYKA, JEP HEMBERGER, PH NOGAR, NS TI DETERMINATION OF POSITIONS, VELOCITIES, AND KINETIC ENERGIES OF RESONANTLY EXCITED IONS IN THE QUADRUPOLE ION-TRAP MASS-SPECTROMETER BY LASER PHOTODISSOCIATION SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID PAUL TRAPS; EXCITATION; SIMULATION; CLOUDS AB The effects on ion motion caused by the application of a resonance AC dipole voltage to the end-cap electrodes of the quadrupole ion trap are described. An excimer laser is used to photodissociate benzoyl ions, and its triggering is phase locked to the AC voltage to follow the motion of the ion cloud as a function of the phase angle of the AC signal. Resonantly excited ions maintain a coherent motion in the presence of He buffer gas, which dissipates energy from the ions via collisions. Maximum ion displacements, which depend upon the potential well depth (q(z) value), occur twice each AC cycle. Axial components of ion velocities are determined by differentiating the displacements of the distributions with respect to time. The experimental data show that these velocities are maximized when the ion cloud passes through zero axial displacement, and they compare favorably with results calculated using a simple harmonic oscillator model. Axial components of ion kinetic energies are low (<5 eV) under the chosen experimental conditions. At low values of q(z) (approximately 0.2), the width of the ion distribution increases as the ion cloud approaches the center of the trap and decreases as it approaches the end-cap electrodes. This effect is created by compaction of the ion trajectories when ion velocities are decreased. C1 PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. FINNIGAN MAT CORP,SAN JOSE,CA. LOS ALAMOS NATL LAB,DIV CLS,LOS ALAMOS,NM 87544. RI Cooks, R/G-1051-2015 OI Cooks, R/0000-0002-9581-9603 NR 44 TC 25 Z9 25 U1 0 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD OCT PY 1993 VL 4 IS 10 BP 792 EP 797 DI 10.1016/1044-0305(93)80037-Y PG 6 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA LZ488 UT WOS:A1993LZ48800006 PM 24227464 ER PT J AU MA, YP DOEFF, MM VISCO, SJ DEJONGHE, LC AF MA, YP DOEFF, MM VISCO, SJ DEJONGHE, LC TI RECHARGEABLE NA NAXCOO2 AND NA15PB4 NAXCOO2 POLYMER ELECTROLYTE CELLS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID SODIUM; INSERTION; LITHIUM; DENSITY AB Cells using polyethylene oxide as a sodium ion conducting electrolyte, P2 phase NaxCoO2 as the positive electrode ans either sodium or sodium/lead alloy as the negative electrode were assembled, discharged, and cycled. NaxCoO2 intercalates sodium over a range of x = 0.3-0.9, giving theoretical energy densities of 1600 Wh/liter (for sodium) or 1470 Wh/liter (for sodium/lead alloy). Cells could be discharged at rates UP to 2.5 mA/cm2 Corresponding to 25% depth of discharge and typically were discharged and charged at 6.5 mA/cm2 (100% depth of discharge) or approximately 1-2 C rate. Over one hundred cycles to 60% utilization or more, and two hundred shallower cycles at this rate have been obtained in this laboratory. Experimental evidence suggests that the cathode is the limiting factor in determining cycle life and not the Na/PEO interface as previously thought. Estimates of practical energy and power densities based on the cell performances and the following configuration are presented: 30-45 w/o electroactive material in the positive electrode, a twofold excess of sodium, 10 mum separators, and 5 mum current collectors composed of metal coated plastic. On the basis of these calculations, practical power densities of 335 W/liter for continuous discharge at 0.5 mA/cm2 and up to 2.7 kW/liter for short periods of time should be attainable. This level of performance approaches or exceeds that seen for some lithium/polymer systems under consideration for electric vehicle applications, but with a lower anticipated cost. RP MA, YP (reprint author), LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Doeff, Marca/G-6722-2013 OI Doeff, Marca/0000-0002-2148-8047 NR 27 TC 57 Z9 60 U1 2 U2 24 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 OCT PY 1993 VL 140 IS 10 BP 2726 EP 2733 DI 10.1149/1.2220900 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA MD880 UT WOS:A1993MD88000004 ER PT J AU WILSON, MS GARZON, FH SICKAFUS, KE GOTTESFELD, S AF WILSON, MS GARZON, FH SICKAFUS, KE GOTTESFELD, S TI SURFACE-AREA LOSS OF SUPPORTED PLATINUM IN POLYMER ELECTROLYTE FUEL-CELLS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID PHOSPHORIC-ACID; CARBON AB Life tests of polymer-electrolyte fuel cells using supported Pt catalyst in thin film catalyst layers are run for up to 4000 h at maximum power. Particle ripening is readily evident using these types of electrodes in which the high catalyst utilization efficiency apparently subjects the majority of the platinum to conditions that sustain particle growth. X-ray diffraction analyses indicate that the initial platinum specific surface areas of 100 m2/g Pt eventually stabilize to about 40 to 50 m2/g in the cathode and 60 to 70 m2/g in the anode. Interestingly, this loss in surface area does not affect the apparent catalytic activity of these fuel cell electrodes. A crystallite migration particle growth mechanism is suggested by the shape of the particle size distribution curves. Since the presence of liquids is known to lower the activation energy for particle growth, the particle size difference between the two electrodes may possibly be attributable to the different hydration levels at the anode and the cathode in operating polymer electrolyte fuel cells. C1 LOS ALAMOS NATL LAB,CERAM SCI & TECHNOL,LOS ALAMOS,NM 87545. RP WILSON, MS (reprint author), LOS ALAMOS NATL LAB,ELECTR MAT & DEVICE RES,LOS ALAMOS,NM 87545, USA. NR 20 TC 301 Z9 305 U1 3 U2 35 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 OCT PY 1993 VL 140 IS 10 BP 2872 EP 2877 DI 10.1149/1.2220925 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA MD880 UT WOS:A1993MD88000029 ER PT J AU BARTRAM, ME HOWARD, AJ BACA, AG SHUL, RJ RIEGER, DJ AF BARTRAM, ME HOWARD, AJ BACA, AG SHUL, RJ RIEGER, DJ TI A NEW METHOD FOR PROMOTING PHOTORESIST ADHESION ON TUNGSTEN FILMS FOR SELF-ALIGNED REFRACTORY GATES ON GAAS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB A new method has been developed for promoting the adhesion of a cresol-formaldehyde novolak resin-based photoresist (AZ5214-E) on tungsten films sputter-deposited on GaAs. Tungsten treated with heated propylene glycol monomethyl ethyl acetate followed by a solvent rinse results in a nonpolar surface which is suitable for reliable photoresist adhesion promotion. This Si-free process has allowed a subtractive dry etch tungsten patterning process to be applied for the first time to the fabrication of self-aligned refractory gates for a novel field-effect transistor. Systematic testing of the new method suggests that dissociative chemisorption of the photoresist solvent is responsible for creating a nonpolar surface for adhesion of the photoresist. In addition to these results, an explanation for the failure of a number of alkylsilyl-based compounds to promote photoresist adhesion on tungsten is presented. RP BARTRAM, ME (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 8 TC 0 Z9 0 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 OCT PY 1993 VL 140 IS 10 BP 2998 EP 3001 DI 10.1149/1.2220946 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA MD880 UT WOS:A1993MD88000050 ER PT J AU SMITH, RD WAHL, JH LIGHTWAHL, KJ WINGER, BE AF SMITH, RD WAHL, JH LIGHTWAHL, KJ WINGER, BE TI NEW DEVELOPMENTS IN MICROSCALE SEPARATIONS AND MASS-SPECTROMETRY FOR BIOMONITORING - CAPILLARY ELECTROPHORESIS AND ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS ID ZONE ELECTROPHORESIS; FLUORESCENCE AB In this article, we briefly highlight the use of capillary electrophoresis for sampling, manipulating, and separating extremely small sample sizes. The extraordinary sensitivity that can be obtained by combined capillary electrophoresis-mass spectrometry is then demonstrated using recent results. We briefly describe the ability to detect noncovalently associated complexes (e.g., double-stranded DNA) by electrospray ionization-mass spectrometry, and conclude with recent results that show the potential for using high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry for characterization of biomolecules. RP SMITH, RD (reprint author), PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 14 TC 6 Z9 6 U1 0 U2 2 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 147 EP 158 PG 12 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700002 PM 7693958 ER PT J AU EDMONDS, CG LOO, JA SMITH, RD FUCIARELLI, AF THRALL, BD MORRIS, JE SPRINGER, DL AF EDMONDS, CG LOO, JA SMITH, RD FUCIARELLI, AF THRALL, BD MORRIS, JE SPRINGER, DL TI EVALUATION OF HISTONE SEQUENCE AND MODIFICATIONS BY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY AND TANDEM MASS-SPECTROMETRY SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS C1 PACIFIC NW LAB, DEPT BIOL & CHEM, RICHLAND, WA 99352 USA. RP EDMONDS, CG (reprint author), PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 FU NIGMS NIH HHS [GM 474423] NR 0 TC 8 Z9 8 U1 0 U2 1 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 159 EP 159 PG 1 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700003 PM 8230293 ER PT J AU SPRINGER, DL BULL, RJ GOHEEN, SC SYLVESTER, DM EDMONDS, CG AF SPRINGER, DL BULL, RJ GOHEEN, SC SYLVESTER, DM EDMONDS, CG TI ELECTROSPRAY-IONIZATION MASS-SPECTROMETRIC CHARACTERIZATION OF ACRYLAMIDE ADDUCTS TO HEMOGLOBIN SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS ID ELECTROPHORESIS; GLYCIDAMIDE; DOSIMETRY; EXPOSURE; SPECTRA; MICE; RAT AB The most common procedure to identify hemoglobin adducts has been to cleave the adducts from the protein and characterize the adducting species, by, for example, derivatization and gas chromatography/mass spectrometry. To extend these approaches we used electrospray ionization mass spectrometry (ESI-MS) to characterize adducted hemoglobin. For this we incubated [C-14]acrylamide with the purified human hemoglobin (type A0 under conditions that yielded high adduct levels. When the hemoglobin was separated by reversed-phase high-performance liquid chromatography (HPLC), 65% of the radioactivity copurified with the beta-subunit. Three adducted species were prominent in the ESI mass spectrum of the intact beta-subunit, indicating acrylamide adduction (i.e., mass increase of 71 Da) and two additional unidentified moieties with mass increments of 102 and 135 Da. Endoproteinase Glu-C digestion of the adducted beta-subunit resulted in a peptide mixture that, upon reversed-phase HPLC separation, provided several radiolabeled peptides. Using ESI-MS we identified these as the V91-101 and V102-122 peptides that represent the cysteine-containing peptides of the beta-subunit. These results provide definitive information on acrylamide-modified human hemoglobin and demonstrate that ESI-MS provides valuable structural information on chemically adducted proteins. C1 WASHINGTON STATE UNIV, COLL PHARM, PULLMAN, WA 99164 USA. PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. RP SPRINGER, DL (reprint author), PACIFIC NW LAB, DEPT BIOL & CHEM, P7-56,POB 999, RICHLAND, WA 99352 USA. NR 30 TC 30 Z9 30 U1 0 U2 2 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 161 EP 176 PG 16 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700004 PM 8230294 ER PT J AU HELMENSTINE, A UZIEL, M VODINH, T AF HELMENSTINE, A UZIEL, M VODINH, T TI MEASUREMENT OF DNA-ADDUCTS USING SURFACE-ENHANCED RAMAN-SPECTROSCOPY SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS AB Hazardous pollutants emitted from energy-related technologies, chemical industries, or waste materials are of increasing public concern because of their potential adverse health effects. Many pollutants have chemical groups of toxicological importance that can be characterized and detected by Raman spectroscopy. Raman spectroscopy, however, has not been widely used in trace organic detection, even though the information contained in a Raman spectrum is valuable for chemical identification. One limitation of conventional Raman spectroscopy is its low sensitivity, which often necessitates the use of powerful and costly laser sources for sample excitation. Raman spectroscopists have recently been able to analyze dilute biological samples as a result of enhancements in the Raman scattering cross section by factors up to 10(10) when a compound is adsorbed on or near a special electron-conducting surface. These spectacular enhancement factors of the normally weak Raman scattering process help overcome the low sensitivity of Raman spectroscopy through a combination of electromagnetic and chemical interactions between the analyte molecule and the surface. The technique associated with this phenomenon is known as surface-enhanced Raman scattering spectroscopy (SERS). The special conductive surface responsible for the scattering enhancement is referred to as a SERS substrate. For the past few years we have developed the SERS technique, using practical SERS-active substrate materials based on silver-coated microspheres deposited on glass. A wide variety of biomarkers have been investigated, including benzo[a]pyrene, dibenz[a,h]anthracene epoxides, 1,N9-ethenoadenine, 3,N4-ethenocytosine, and other substances. These biomarkers were measured at nanogram and subnanogram levels. The experimental results are of great analytical interest, since these chemicals are difficult to detect by other techniques, such as luminescence spectroscopy, because of the weak luminescence quantum yields of these DNA adducts. In this paper the potential usefulness of the SERS technique for assessing environmental and health effects from human exposure to toxic pollutants is demonstrated. C1 OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,ADV MONITORING DEV GRP,OAK RIDGE,TN 37831. NR 7 TC 10 Z9 10 U1 0 U2 6 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 195 EP 202 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700006 PM 8230295 ER PT J AU MEZNARICH, HK MCCOY, LS BALE, TL STIEGLER, GL SIKOV, MR AF MEZNARICH, HK MCCOY, LS BALE, TL STIEGLER, GL SIKOV, MR TI BRAIN FIBRONECTIN EXPRESSION IN PRENATALLY IRRADIATED MICE SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS ID CELL MATRIX INTERACTIONS; INDUCED LUNG INJURY; IONIZING-RADIATION; X-IRRADIATION; MESSENGER-RNA; CYTOSKELETAL ELEMENTS; ADHESION MOLECULES; GENE-EXPRESSION; LAMININ; PROTOONCOGENE AB Activation of gene transcription by radiation has been recently demonstrated in vitro. However, little is known on the specificity of these alterations on gene transcription. Prenatal irradiation is a known teratogen that affects the developing mammalian central nervous system (CNS). Altered neuronal migration has been suggested as a mechanism for abnormal development of prenatally irradiated brains. Fibronectin (FN), an extracellular glycoprotein, is essential for neural crest cell migration and neural cell growth. In addition, elevated levels of FN have been found in the extracellular matrix of irradiated lung. To test whether brain FN is affected by radiation, either FN level in insoluble matrix fraction or expression of FN mRNA was examined pre- and postnatally after irradiation. Mice (CD1), at 13 d of gestation (DG), served either as controls or were irradiated with gamma rays at 0.5 or 1 Gy. Control and irradiated animals were killed either at 13 DG, 14 DG, 17 DG, or 5, 6, or 14 d postnatal. Brain and liver were collected from offspring and analyzed for either total FN protein levels or relative mRNAs for FN and tubulin. Results of prenatal irradiation on reduction of postnatal brain weight relative to whole body weight and morphological reduction in cerebral cortex regions of postnatal brains are comparable to that reported by others. Insoluble matrix fraction (IMF) per gram of brain, liver, lung, and heart weight was not significantly different either between control and irradiated groups or between postnatal stages, suggesting that radiation did not affect the IMF. However, total amounts of FN in brain IMF at 17 DG were significantly different (p <.02) between normal (1.66 +/- 0.80 mug) and irradiated brains (0.58 +/- 0.22 mug). FN mRNA was detectable at 13, 14, and 17 DG, but was not detectable at 6 and 14 d postnatal, indicating that FN mRNA is developmentally regulated. After 0.5 Gy of irradiation, expression of FN mRNA was reduced to 36% +/- 22% (1 h), 52% +/- 10% (1 d), and 76% +/- 10% (4 d) of the control level. After 1 Gy of irradiation, relative FN mRNA was 62% +/- 28% (1 h) and 75% +/- 3% (4 days) to the control level, respectively. This reduction was comparable to that reported by others for the cytoskeletal protein beta-actin. In contrast, mRNA for tubulin, another cytoskeletal protein, increased at 1 h after irradiation but then approached normal postnatally. The longer lasting alteration of FN may be more directly related to neural development, particularly if the reduction in FN is nonuniform. RP MEZNARICH, HK (reprint author), PACIFIC NW LAB, DEPT BIOL & CHEM, POB 999 P7-53, RICHLAND, WA 99352 USA. NR 41 TC 7 Z9 7 U1 0 U2 1 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 263 EP 275 PG 13 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700012 PM 8230301 ER PT J AU BROOKS, AL KHAN, MA JOSTES, RF CROSS, FT AF BROOKS, AL KHAN, MA JOSTES, RF CROSS, FT TI METAPHASE CHROMOSOME-ABERRATIONS AS MARKERS OF RADIATION EXPOSURE AND DOSE SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article; Proceedings Paper CT 31ST HANFORD SYMP ON HEALTH AND THE ENVIRONMENT CY OCT 20-23, 1992 CL RICHLAND, WA SP US DOE, BATTELLE, PACIFIC NW LABS, UNIV WASHINGTON SCH PUBLIC HLTH AND COMMUNITY MED, DEPT ENVIRONM HLTH, NIEHS ID FLUORESCENCE INSITU HYBRIDIZATION; HUMAN-LYMPHOCYTES; DNA; TRANSLOCATIONS; RADON AB Chromosome aberration frequency provides the most reliable biological marker of dose to detect acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses (Lloyd et al., 1992). In animal studies chromosome aberrations provide a method to relate exposure to cellular dose. Using an in vivo/in vitro approach, aberrations provided a biological marker of dose from radon progeny exposure, which was used to convert exposure, work level months (WLM) to dose in grays (Gy) delivered to rat tracheal epithelial cells. injection of Chinese hamsters with Ce-144, which produced a low-dose rate exposure of bone marrow to low-linear energy transfer (LET) radiation, increased the cell sensitivity for the induction of chromatid exchanges by subsequent external Co-60 exposure. Our paper provides information on using molecular chromosome probes to ''paint'' chromosomes and score chromosome damage. This approach illustrates how technical advances make it possible to understand the mechanisms involved in the formation of chromosome aberrations. These studies demonstrate the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness. RP BROOKS, AL (reprint author), PACIFIC NW LAB, DEPT BIOL & CHEM, CELLULAR & MAMMALIAN BIOL SECT, BATTELLE BLVD, RICHLAND, WA 99352 USA. FU NCI NIH HHS [R01 CA45590] NR 35 TC 16 Z9 17 U1 1 U2 3 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 277 EP 288 PG 12 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700013 PM 8230302 ER PT J AU SEVER, LE SMITH, R SPRINGER, DC JARVIS STANSBURY WOODS, JS HULKA, BS SCHULTE OMIECINSKI, CJ TENFORDE STENNER STEVENS AF SEVER, LE SMITH, R SPRINGER, DC JARVIS STANSBURY WOODS, JS HULKA, BS SCHULTE OMIECINSKI, CJ TENFORDE STENNER STEVENS TI LOOKING INTO THE CRYSTAL BALL - THE DEVELOPMENT AND APPLICATION OF BIOMARKERS TO THE STUDY OF HUMAN HEALTH-EFFECTS SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Discussion C1 PACIFIC NW LAB, DEPT BIOL & CHEM, RICHLAND, WA 99352 USA. BATTELLE MEM INST, SEATTLE RES CTR, SEATTLE, WA USA. UNIV WASHINGTON, SCH PUBL HLTH & COMMUNITY MED, DEPT ENVIRONM HLTH, SEATTLE, WA 98195 USA. UNIV N CAROLINA, DEPT EPIDEMIOL, CHAPEL HILL, NC 27599 USA. RP SEVER, LE (reprint author), PACIFIC NW LAB, DEPT PHARM PRACTICE, RICHLAND, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD OCT-NOV PY 1993 VL 40 IS 2-3 BP 465 EP 492 PG 28 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA MJ197 UT WOS:A1993MJ19700030 ER PT J AU DUNBAR, NW RICIPUTI, LR JACOBS, GK NANEY, MT CHRISTIE, W AF DUNBAR, NW RICIPUTI, LR JACOBS, GK NANEY, MT CHRISTIE, W TI GENERATION OF RHYOLITIC MELT IN AN ARTIFICIAL MAGMA - IMPLICATIONS FOR FRACTIONAL CRYSTALLIZATION PROCESSES IN NATURAL MAGMAS SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article ID DIFFERENTIATION; CHAMBERS; ROCKS AB A large (1.3x 10(7) g) artificial mafic melt with a bulk composition similar to an unusually calcic basalt (17 wt.% CaO) was produced by in-situ heating of soil, and subsequently cooled and crystallized. The final crystalline assemblage consisted dominantly of acicular diopsidic to hedenbergitic pyroxene and anorthitic feldspar, with a subordinate amount of potassic feldspar. Electron microprobe analyses reveal the presence of a small amount (approximately 10 vol.%) of rhyolitic glass (71% SiO2) within the crystalline network. This glass is the residual material left after crystallization of pyroxene and feldspar, analogous to rhyolitic melt which may be generated from fractional crystallization of a basaltic magma. Ion microprobe imaging indicates that the rhyolitic glass is generally present in isolated triangular- to rectangular-shaped interstices left by crystallization of acicular and tabular phases, and that the glass is enriched in trace elements (such as Zr and Cs) which are incompatible within the crystalline phases. No evidence of coalescence or migration of the rhyolitic melt is suggested by glass morphology. Although these observations were made in an artificial magmatic system, analogies to a natural system may be drawn. The isolated nature and low abundance of the rhyolitic glass highlights the difficulty of extracting and segregating evolved melts produced by high degrees of crystallization of a primitive parent, particularly one characterized by elongated, rather than equant, crystals. The distribution of the rhyotitic glass supports the suggestion that extraction of significant amounts of evolved melts from rocks may require repeated partial melting of crystallized material in order to allow the evolved liquid to phasically separate from the parent, and also suggests that the geometry of crystals may be an important factor in melt segregation. C1 OAK RIDGE NATL LAB,DEPT ENVIRONM SCI,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DEPT ANALYT CHEM,OAK RIDGE,TN 37831. NR 15 TC 5 Z9 5 U1 1 U2 1 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 OCT PY 1993 VL 57 IS 3-4 BP 157 EP 166 DI 10.1016/0377-0273(93)90010-O PG 10 WC Geosciences, Multidisciplinary SC Geology GA MR800 UT WOS:A1993MR80000002 ER PT J AU KENNAMER, RA MCCREEDY, CD BRISBIN, IL AF KENNAMER, RA MCCREEDY, CD BRISBIN, IL TI PATTERNS OF RADIOCESIUM CONTAMINATION IN EGGS OF FREE-RANGING WOOD DUCKS SO JOURNAL OF WILDLIFE MANAGEMENT LA English DT Article ID RADIONUCLIDES; VARIANCE; SWALLOWS AB Studies of biological consequences of nuclear industrial contaminants in the environment increase in importance as the potential for exposure of wildlife populations rises. Thus, we examined levels of radiocesium (cesium-137) contamination in wood duck (Aix sponsa) eggs from a Department of Energy nuclear facility in South Carolina during 1990. Radiocesium levels in individual eggs from 5 locations on the site ranged from below detectable concentrations (<0.147 Bq/g) to a maximum of 2.21 Bq/g wet mass. Eggs from an abandoned reactor cooling reservoir contained the greatest burdens; mean egg concentrations there were more than an order of magnitude higher than those from other locations studied. Eggs from a second abandoned cooling reservoir, Carolina Bays, and 2 lotic ecosystems, one of which had received reactor effluent radionuclide releases, all contained similar low radiocesium levels that were, on average, below detection limits. Variation in radiocesium concentrations of eggs from the most contaminated cooling reservoir was partitioned into within- and among-clutch variation. Approximately 33% of the variation in radiocesium content occurred among eggs laid by the same female, and may have resulted because females fed in both contaminated and uncontaminated habitats during egg formation. Radiation dose rates to developing wood duck embryos, resulting from internal and external sources examined in this study, were below those expected to affect hatchability or any other aspect of the breeding biology of these birds. Wood ducks and their eggs may be useful as bioindicators of radiocesium uptake, but we caution that local foraging patterns could cause variation in contaminant deposition within clutches. RP KENNAMER, RA (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29801, USA. NR 45 TC 11 Z9 12 U1 0 U2 2 PU WILDLIFE SOC PI BETHESDA PA 5410 GROSVENOR LANE, BETHESDA, MD 20814-2197 SN 0022-541X J9 J WILDLIFE MANAGE JI J. Wildl. Manage. PD OCT PY 1993 VL 57 IS 4 BP 716 EP 724 DI 10.2307/3809071 PG 9 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA MB571 UT WOS:A1993MB57100008 ER PT J AU MCCORQUODALE, SM AF MCCORQUODALE, SM TI WINTER FORAGING BEHAVIOR OF ELK IN THE SHRUB-STEPPE OF WASHINGTON SO JOURNAL OF WILDLIFE MANAGEMENT LA English DT Article ID HABITAT USE; MULE DEER; QUALITY; SELECTION; COLORADO; DIETS AB Numerous models of ungulate foraging behavior have been published, but data on foraging behavior for wild North American ungulates relevant to model testing are scarce. I studied the detailed foraging behavior of elk (Cervus elaphus) from autumn through early spring in Washington's shrub-steppe using focal animal sampling and collected corollary data on elk diets, forage quality, and home ranges. I tested the hypotheses that foraging effort is proportional to energetic payoffs determined by the quality and abundance of various forages, and elk home-range size reflects relative foraging movements (i.e., macro and micro movements are related). Elk were mobile foragers during autumn and spring and were relatively sedentary during mid-winter. High mobility was associated with low diet diversity and generally with reduced forage harvesting rates. This mobile foraging occurred during periods of higher quality forage availability. Thus, mobile foraging appeared to reflect increased effort when energetic payoffs of selective foraging were enhanced. Degree of dietary specialization was limited by the relative abundance of preferred forages, being greater when grass quality was high, and less when forb quality was high. Indices of elk movement while foraging were also positively related to home-range size and distance between relocations of radio-collared elk. These data are generally consistent with ungulate foraging model predictions. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 34 TC 17 Z9 17 U1 1 U2 3 PU WILDLIFE SOC PI BETHESDA PA 5410 GROSVENOR LANE, BETHESDA, MD 20814-2197 SN 0022-541X J9 J WILDLIFE MANAGE JI J. Wildl. Manage. PD OCT PY 1993 VL 57 IS 4 BP 881 EP 890 DI 10.2307/3809093 PG 10 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA MB571 UT WOS:A1993MB57100030 ER PT J AU BURTON, HD AF BURTON, HD TI WOMEN IN CHEMISTRY AND PHYSICS - A BIOBIBLIOGRAPHIC SOURCEBOOK - GRINSTEIN,LS SO LIBRARY JOURNAL LA English DT Book Review RP BURTON, HD (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD OCT 1 PY 1993 VL 118 IS 16 BP 90 EP 90 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA LZ834 UT WOS:A1993LZ83400045 ER PT J AU PEYTON, BW POTHEN, A YUAN, XQ AF PEYTON, BW POTHEN, A YUAN, XQ TI PARTITIONING A CHORDAL GRAPH INTO TRANSITIVE SUBGRAPHS FOR PARALLEL SPARSE TRIANGULAR SOLUTION SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT WORKSHOP ON COMPUTATIONAL LINEAR ALGEBRA IN ALGEBRAIC AND RELATED PROBLEMS CY JUL 27-31, 1992 CL ESSEN UNIV, INST EXPTL MATH, ESSEN, GERMANY SP DEUT FORSCHUNGSGEMEINSCH, VOLKSWAGEN FDN, ESSEN UNIV, IBM DEUTSCHLAND, SIEMENS HO ESSEN UNIV, INST EXPTL MATH ID ELIMINATION AB A recent approach for solving sparse triangular systems of equations on massively parallel computers employs a factorization of the triangular coefficient matrix to obtain a representation of its inverse in product form. The number of general communication steps required by this approach is proportional to the number of factors in the factorization. The triangular matrix can be symmetrically permuted to minimize the number of factors over suitable classes of permutations, and thereby the complexity of the parallel algorithm can be minimized. Algorithms for minimizing the number of factors over several classes of permutations have been considered in earlier work. Let F = L + L(T) denote the symmetric filled matrix corresponding to a Cholesky factor L, and let G(F) denote the adjacency graph of F. We consider the problem of minimizing the number of factors over all permutations which preserve the structure of G(F). The graph model of this problem is to partition the vertices G(F) into the fewest transitively closed subgraphs over all perfect elimination orderings while satisfying a certain precedence relationship. The solution to this chordal-graph partitioning problem can be described by a greedy scheme which eliminates a largest permissible subgraph at each step. Further, the subgraph eliminated at each step can be characterized in terms of lengths of chordless paths in the current elimination graph. This solution relies on several results concerning transitive perfect elimination orderings introduced in this paper. We describe a partitioning algorithm with O(Absolute value of V + Absolute value of E) time and space complexity. C1 UNIV WATERLOO,DEPT COMP SCI,WATERLOO N2L 3G1,ONTARIO,CANADA. IBM CORP,CANADA LAB,N YORK M3C 1H7,ON,CANADA. RP PEYTON, BW (reprint author), OAK RIDGE NATL LAB,MATH SCI SECT,POB 2008,BLDG 6012,OAK RIDGE,TN 37831, USA. OI Pothen, Alex/0000-0002-3421-3325 NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD OCT PY 1993 VL 192 BP 329 EP 353 DI 10.1016/0024-3795(93)90248-M PG 25 WC Mathematics, Applied; Mathematics SC Mathematics GA LY733 UT WOS:A1993LY73300016 ER PT J AU GARROTT, RA EBERHARDT, LL BURN, DM AF GARROTT, RA EBERHARDT, LL BURN, DM TI MORTALITY OF SEA OTTERS IN PRINCE-WILLIAM SOUND FOLLOWING THE EXXON-VALDEZ OIL-SPILL SO MARINE MAMMAL SCIENCE LA English DT Article DE BOOTSTRAPPING; BOAT SURVEYS; CENSUS TECHNIQUES; SIGHTING PROBABILITIES; MORTALITY; POPULATION GROWTH; CONTAMINANTS; ENHYDRA-LUTRIS; IMPACTS OF OIL SPILL; CARCASS RECOVERY RATES; PRINCE-WILLIAM SOUND; ALASKA AB This paper presents an estimate of the total number of sea otters that died as a direct consequence of the oil spill that occurred when the T/V Exxon Valdez grounded in Prince William Sound, Alaska on 24 March 1989. We compared sea otter counts conducted from small boats throughout the Sound during the summers of 1984 and 1985 to counts made after the spill during the summer of 1089. We used ratio estimators, corrected for sighting probability, to calculate otter densities and population estimates for portions of the Sound affected by die oil spill. We estimated the otter population in the portion of Prince William Sound affected by the oil was 6,546 at the time of the spill and that the post-spill population in the summer of 1989 was 3,898, yielding a loss estimate of approximately 2,650. Bootstrapping techniques were used to approximate confidence limits on die loss estimate of about 500-5,000 otters. The wide confidence limits are a result of die complex scheme required to estimate losses and limitations of the data. Despite the uncertainty of the loss estimate it is dear that a significant fraction of the otters in the spill zone survived. We observed otters persisting in relatively dean embayments throughout the oil spill zone suggesting that the highly convoluted coastline of Prince William Sound produced refuges that allowed some. sea otters in the oil spill area to survive. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. US FISH & WILDLIFE SERV, MARINE MAMMALS MANAGEMENT, ANCHORAGE, AK 99508 USA. RP GARROTT, RA (reprint author), UNIV WISCONSIN, DEPT WILDLIFE ECOL, 226 RUSSELL LABS, MADISON, WI 53706 USA. NR 22 TC 45 Z9 45 U1 3 U2 29 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD OCT PY 1993 VL 9 IS 4 BP 343 EP 359 DI 10.1111/j.1748-7692.1993.tb00468.x PG 17 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA MH887 UT WOS:A1993MH88700001 ER PT J AU CHAWLA, KK CHOUDHURY, A VENKATESH, R HELLMANN, JR AF CHAWLA, KK CHOUDHURY, A VENKATESH, R HELLMANN, JR TI MICROSTRUCTURAL CHARACTERIZATION BY SECONDARY-ION MASS-SPECTROMETRY OF (ALUMINA PLUS ZIRCONIA) FIBER GLASS COMPOSITES WITH AND WITHOUT A TIN DIOXIDE INTERPHASE SO MATERIALS CHARACTERIZATION LA English DT Article ID MATRIX COMPOSITES; HIGH-STRENGTH; TOUGHNESS AB Alumina + zirconia fiber (PRD-166)/glass (N51A) matrix composites were fabricated with and without a tin dioxide barrier layer. A qualitative comparison of the elemental distribution was made between the two composite systems by secondary ion microscopy. Secondary ion mass spectrometry would appear to be especially useful to obtain the distribution of light elements such as B, Na, Cl, etc. in ceramic and glass composites. Our study of PRD-166/glass and PRD-166/SnO2/glass composites shows that tin dioxide serves as an effective barrier between this (alumina + zirconia) fiber and the silica-based glass. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. PENN STATE UNIV,STATE COLL,PA 16803. RP CHAWLA, KK (reprint author), NEW MEXICO INST MIN & TECHNOL,SOCORRO,NM 87801, USA. NR 20 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1044-5803 J9 MATER CHARACT JI Mater. Charact. PD OCT PY 1993 VL 31 IS 3 BP 167 EP 176 DI 10.1016/1044-5803(93)90057-3 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA MA198 UT WOS:A1993MA19800005 ER PT J AU THOMPSON, RB AF THOMPSON, RB TI ULTRASONIC CHARACTERIZATION OF TEXTURE AND FORMABILITY OF ROLLED METAL SHEETS SO MATERIALS EVALUATION LA English DT Article DE ALUMINUM; ELECTROMAGNETIC ACOUSTIC TRANSDUCERS; ALUMINUM; NONDESTRUCTIVE CHARACTERIZATION; PLASTIC DEFORMATION; STEEL; TRANSDUCERS; TUBING; ULTRASONIC TESTING AB The texture (preferred grain orientation) of metal sheet plays a central role in determining the material's response to subsequent deformation. Recent advances in inferring forming characteristics from ultrasonic velocity measurements are reviewed. After a brief discussion of the underlying physical principles, progress towards the prediction of the normal anisotropy of steel sheet,a parameter that is important in determining the ability of the sheet to be deeply drawn into a variety of shapes such as those used in automobile door panels, is reviewed. Less well developed applications such as the prediction of the earing behavior of aluminum sheet and of the Kearns texture parameters of hexagonal metal sheet and tubing are then summarized. The paper concludes with a discussion of possible directions of future research. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT ENGN MECH,AMES,IA 50011. RP THOMPSON, RB (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,CTR NDE,AMES,IA 50011, USA. NR 22 TC 3 Z9 3 U1 2 U2 3 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD OCT PY 1993 VL 51 IS 10 BP 1162 EP & PG 0 WC Materials Science, Characterization & Testing SC Materials Science GA MC453 UT WOS:A1993MC45300007 ER PT J AU SMARTT, HB JOHNSON, JA EINERSON, CJ AF SMARTT, HB JOHNSON, JA EINERSON, CJ TI THE ROLE OF INTELLIGENT SYSTEMS IN WELD PROCESS-CONTROL SO MATERIALS EVALUATION LA English DT Article DE ARTIFICIAL INTELLIGENCE; FUZZY SYSTEMS; INTELLIGENT SYSTEMS; NONDESTRUCTIVE TESTING; NEURAL NETWORKS; QUALITY CONTROL; WELDING AB In materials processing, the process parameters are generally controlled based on knowledge of the relationships between the parameters and the desired material properties. Post-processing quality control is then used to determine if the processing was successful. A primary goal of intelligent sensing and control is to bring quality control into the process by incorporating sensing capability, knowledge of process physics, control capability, and process engineering such that the intelligent processing system is aware of the state of the process and knows how to make a good product based on that awareness. Methods of incorporating intelligent systems, such as fuzzy expert systems and artificial neural networks, into control schemes are discussed along with standard classical and modern control theory. The methods of intelligent systems such as neural networks and fuzzy systems are often means of generating an input-output mapping function. An example of an intelligent control system employs both fuzzy logic and a neural network to control heat input and mass input in gas metal arc welding (GMAW). Two cameras are used to measure the area of the joint to be filled and the temperature gradient in the solidified weld metal. This information is processed by a fuzzy logic system to determine the required mass to fill the joint and the heat input to the weld to maintain a specified cooling rate. This information is processed by a neural network which maps this to the welding parameters, travel speed and electrode speed. Hardware actuators on the weld machine then implement the require values. RP SMARTT, HB (reprint author), IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 24 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD OCT PY 1993 VL 51 IS 10 BP 1166 EP 1173 PG 8 WC Materials Science, Characterization & Testing SC Materials Science GA MC453 UT WOS:A1993MC45300008 ER PT J AU HENAGER, CH BRUEMMER, SM HIRTH, JP AF HENAGER, CH BRUEMMER, SM HIRTH, JP TI STRENGTH AND TOUGHNESS OF BERYLLIUM NIOBIUM INTERMETALLIC COMPOUNDS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT CONF ON THE SCIENCE OF ORDERED INTERMETALLIC ALLOYS - STRUCTURAL MATERIALS : PROPERTIES, MICROSTRUCTURE AND PROCESSING CY OCT 14-15, 1992 CL NAVAL SURFACE WARFARE CTR, ANNAPOLIS, MD SP USN, OFF NAVAL RES HO NAVAL SURFACE WARFARE CTR ID BE12NB AB Bend and compression strengths, fracture toughness, and high-temperature microhardness of Be-Nb intermetallic compounds were measured at temperatures up to 1200-degrees-C. Be12Nb and Be17Nb2 materials exhibited brittle behavior at temperatures below 1100-degrees-C in bending and below 800-degrees-C in compression. Hot isostatically pressed (HIP) Be12Nb had the highest low-temperature strengths (250 MPa in bending and 2750 MPa in compression) resulting from its greater fracture toughness (K(IC)=4 MPa M1/2) compared with the other Be-Nb materials, vacuum hot pressed (BBP)Be12Nb, and HIP Be17Nb2, which had K(IC)=2.5 MPa m1/2. Measured strengths for the HIP Be12Nb were more than twice that measured for the VHP Be12Nb or for VHP Be17Nb2. The HIP Be12Nb also exhibited good high-temperature mechanical properties, having a bend strength of 250 MPa at 1200-degrees-C, compared with less than 100 MPa for the VHP Be12Nb. However, intergranular embrittlement was observed at intermediate temperatures, reducing the HIP Be12Nb bend strength and fracture toughness below those measured for the other materials. HIP Be17Nb2 exhibited poor low-temperature properties, but high-temperature bend strengths of 740 MPa at 1100-degrees-C and 400 MPa at 1200-degrees-C were measured. Strength in compression was similar for all materials above 800-degrees-C, decreasing sharply to about 600 MPa at 1000-degrees-C and to 200 MPa at 1200-degrees-C. Microhardness and indentation creep tests also revealed similar high-temperature behavior among the materials. Power-law creep exponents ranging from 4.1 to 6.6 and activation energies of 220-290 kJ mol were measured for the beryllides, with the HIP Be12Nb having the highest activation energy for creep. C1 WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA. RP HENAGER, CH (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. OI Henager, Chuck/0000-0002-8600-6803 NR 27 TC 0 Z9 0 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 OCT 1 PY 1993 VL 170 IS 1-2 BP 185 EP 197 DI 10.1016/0921-5093(93)90380-W PG 13 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ME438 UT WOS:A1993ME43800019 ER PT J AU OHNUMA, M SASAKI, O KUWANO, H KATANO, S MORII, Y FUNAHASHI, S CHILD, HR HAMAGUCHI, Y AF OHNUMA, M SASAKI, O KUWANO, H KATANO, S MORII, Y FUNAHASHI, S CHILD, HR HAMAGUCHI, Y TI CRYSTALLIZATION PROCESS OF FE80P20-XSIX AMORPHOUS-ALLOYS SO MATERIALS TRANSACTIONS JIM LA English DT Article DE IRON-PHOSPHORUS-SILICON AMORPHOUS ALLOY; CRYSTALLIZATION PROCESS; X-RAY DIFFRACTION; NEUTRON DIFFRACTION; TRANSMISSION ELECTRON MICROSCOPY; METASTABLE PHASE; FRANK-KASPER COORDINATION POLYHEDRON AB The crystallization process of Fe80P20-xSix amorphous alloys has been studied by electrical resistivity, X-ray diffraction, neutron diffraction, and transmission electron microscopy. This process is classified into two different patterns with a boundary of 6 at%Si. In the alloys containing less than 6 at%Si, alpha-Fe and Fe3P, both of which are stable phases, precipitate from the amorphous matrix directly. In the crystallization of the amorphous alloys containing over 6 at%Si, two complex phases are observed in the early stages. We found that these two phases are isostructural with the alpha-Mn type and beta-Mn type phase. After these two metastable phases disappear, another metastable phase which is probably Fe2P appears. In the final stage of the crystallization, however, existing crystalline phases are stable alpha-Fe (or ordered Fe3Si) and Fe3P. In the isothermal crystallization process of the Fe80P14Si6 amorphous alloy, only the alpha-Mn type phase is observed as the metastable phase at high temperatures such as 683, 703 and 723 K; however, at a lower temperature such as 668 K, no metastable phase is observed. The precipitation of the metastable alpha-Mn type and/or beta-Mn type phases, which consist of the Frank-Kasper coordination polyhedra, can be closely related to the local structure in these amorphous alloys. C1 JAPAN ATOM ENERGY RES INST,DEPT MAT SCI & ENGN,TOKAI,IBARAKI 31911,JAPAN. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP OHNUMA, M (reprint author), MURORAN INST TECHNOL,DEPT MAT SCI & ENGN,MURORAN,HOKKAIDO 050,JAPAN. NR 11 TC 5 Z9 5 U1 0 U2 1 PU JAPAN INST METALS PI SENDAI PA AOBA ARAMAKI, SENDAI 980, JAPAN SN 0916-1821 J9 MATER T JIM JI Mater. Trans. JIM PD OCT PY 1993 VL 34 IS 10 BP 874 EP 881 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA MH141 UT WOS:A1993MH14100002 ER PT J AU LYNESS, JN SOREVIK, T AF LYNESS, JN SOREVIK, T TI LATTICE RULES BY COMPONENT SCALING SO MATHEMATICS OF COMPUTATION LA English DT Article DE LATTICE RULES, NUMBER-THEORETIC RULES; ZAREMBA INDEX; FIGURE OF MERIT; SCALED LATTICE ID INTEGRATION AB We introduce a theory of rectangular scaling of integer lattices. This may be used to construct families of lattices. We determine the relation between the Zaremba index rho(LAMBDA) of various members of the same family. It appears that if one member of a family has a high index, some of the other family members of higher order may have extraordinarily high indices. We have applied a technique based on this theory to lists of good lattices available to us. This has enabled us to construct lists of excellent previously unknown lattices of high order in three and four dimensions and of moderate order in five dimensions. C1 UNIV BERGEN,DEPT INFORMAT,N-5020 BERGEN,NORWAY. RP LYNESS, JN (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439, USA. NR 10 TC 7 Z9 7 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0025-5718 J9 MATH COMPUT JI Math. Comput. PD OCT PY 1993 VL 61 IS 204 BP 799 EP 820 DI 10.2307/2153254 PG 22 WC Mathematics, Applied SC Mathematics GA MC664 UT WOS:A1993MC66400017 ER PT J AU RAO, KTV MCNULTY, JC RITCHIE, RO AF RAO, KTV MCNULTY, JC RITCHIE, RO TI THE EFFECTS OF PROLONGED THERMAL EXPOSURE ON THE FRACTURE AND FATIGUE BEHAVIOR OF ALUMINUM-LITHIUM ALLOY-8090 SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID CRACK CLOSURE; ALLOYS; MICROSTRUCTURE; TOUGHNESS; GROWTH; STEELS; PREDICTION; STRESS; STATE AB Aluminum-lithium alloys are currently being considered for applications at moderately elevated temperatures; accordingly, a study has been made on the effects of prolonged (100 and 1000 hours overaging) thermal exposure at 149-degrees-C and 260-degrees-C on the mechanical properties of a peak-aged Al-Li-Cu-Mg-Zr alloy 8090-T8771. In the as-received T8771 temper, the alloy exhibits an excellent combination of strength (approximately 500 MPa) and toughness (35 MPa square-root m) with moderate tensile elongation (4 pct). Overaging at 149-degrees-C results in a approximately 50 pct reduction in ductility and toughness, primarily associated with the growth of equilibrium phases along grain/subgrain boundaries, resulting in formation of solute-depleted precipitate-free zones and coarsening of matrix delta' and S precipitates; strength levels and fatigue-crack growth rates, however, remain largely unchanged. Thermal exposures at 260-degrees-C, conversely, lead to dramatic reductions in strength (by approximately 50 to 80 pct), toughness (by approximately 30 pct) and fatigue-crack propagation resistance; crack-growth rates at all DELTAK levels above approximately 5 MPa square-root m are 2 to 3 orders of magnitude faster. Microstructurally, this was associated with complete dissolution of delta', severe coarsening of S and T2 precipitates in the matrix, and formation of equilibrium Cu- and Mg-rich intermetallic phases in the matrix and along grain boundaries. The resulting lack of planar-slip deformation and low yield strength of 8090 following overaging exposures at 260-degrees-C increase the cumulative crack-tip damage per cycle and reduce the tendency for crack-path deflection, thereby accelerating fatigue-crack growth rates. Despite this degradation in properties, the 8090-T8771 alloy has better strength retention and generally superior fatigue-crack growth properties compared to similarly overaged Al-Li-Cu-Zr 2090 and Al-Cu-Zn-Mg 7150 alloys. C1 LAWRENCE BERKELEY LAB, CTR ADV MAT, DIV MAT SCI, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV CALIF SANTA BARBARA, COLL ENGN, DEPT MAT, SANTA BARBARA, CA 93106 USA. RP LAWRENCE BERKELEY LAB, DEPT MAT SCI & MINERAL ENGN, BERKELEY, CA 94720 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 39 TC 6 Z9 6 U1 1 U2 7 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0360-2133 J9 METALL TRANS A PD OCT PY 1993 VL 24 IS 10 BP 2233 EP 2245 DI 10.1007/BF02648598 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA MA551 UT WOS:A1993MA55100012 ER PT J AU HAARBERG, GM OSEN, KS THONSTAD, J HEUS, RJ EGAN, JJ AF HAARBERG, GM OSEN, KS THONSTAD, J HEUS, RJ EGAN, JJ TI MEASUREMENT OF ELECTRONIC CONDUCTION IN CRYOLITE ALUMINA MELTS AND ESTIMATION OF ITS EFFECT ON CURRENT EFFICIENCY SO METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY LA English DT Article ID ALLOYS AB The electronic conductivity of molten Na3AlF6 saturated with Al2O3 was determined as a function of the activity of Na at 1000-degrees-C by using the Wagner polarization technique. Typical results showed electronic conductivities of 0.298 ohm-1 cm-1 at a(Na) = 0.04 and 0.084 ohm-1 cm-1 at a(Na) = 0.01. A transient technique employing the same experimental cell was used to determine the diffusion coefficient and the mobility of electrons in this melt. The mobility is 0.33 cm2 V-1 s-1. A model calculation for electrolysis of a melt of cryolite saturated with alumina to produce aluminum metal is presented to show how electronic conductivity effects current efficiency (CE). Under various assumed conditions, which are tabulated, CEs ranged from around 85 to 98 pct at 1000-degrees-C. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP HAARBERG, GM (reprint author), UNIV TRONDHEIM,NORWEGIAN INST TECHNOL,IND ELECTROCHEM LAB,N-7034 TRONDHEIM,NORWAY. NR 31 TC 12 Z9 12 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2141 J9 METALL TRANS B PD OCT PY 1993 VL 24 IS 5 BP 729 EP 735 DI 10.1007/BF02663133 PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA LY902 UT WOS:A1993LY90200002 ER PT J AU LUO, W CLEWLEY, JD FLANAGAN, TB AF LUO, W CLEWLEY, JD FLANAGAN, TB TI CALORIMETRICALLY MEASURED ENTHALPIES FOR THE REACTION OF H2(D2) (G) WITH TI AND TI-NI ALLOYS AT 323-K SO METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY LA English DT Article ID H SYSTEM; ALPHA-PHASE; HYDROGEN; PALLADIUM; THERMODYNAMICS; H-2 AB Reaction enthalpies have been measured calorimetrically at 323 K for the reaction 1/2H-2 (g) + Ti (alpha, hcp) --> TiH1.5 and for the partial molar solution of H-2 in the delta phase. The magnitude of the enthalpy decreases from 68 at H/Ti = 0 to 65 kJ/mol H at H/Ti = 1.5. The enthalpy continues to slowly fall in magnitude with the increase of H content, and then, for (H/Ti) > 1.9, it falls more precipituously. DELTAHf0(TiH1.5) = -98.4 kJ and DELTAHf0(TiH2) = - 130.3 kJ evaluated at 323 K. No differences in enthalpies were found between H and D. The results are discussed in terms of the existing solvus data for this system, which are important for the quantitative understanding of hydride-induced fracture. Enthalpies of reaction with H-2 have been determined for several Ti-Ni alloys which lie in the (Ti(alpha) + Ti2Ni) two-phase field. The reaction with H-2 initially occurs with the Ti phase and then with the Ti2Ni phase. The enthalpies are similar for the Ti phase as for pure Ti, indicating that this phase is relatively pure Ti. Reaction with the Ti2Ni phase shows a plateau region with an enthalpy of reaction with 1/2H2 of about -30 kJ/mol H. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP LUO, W (reprint author), UNIV VERMONT,DEPT CHEM,BURLINGTON,VT 05405, USA. NR 30 TC 7 Z9 7 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2141 J9 METALL TRANS B PD OCT PY 1993 VL 24 IS 5 BP 867 EP 873 DI 10.1007/BF02663147 PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA LY902 UT WOS:A1993LY90200016 ER PT J AU CANNON, TW HULSTROM, RL AF CANNON, TW HULSTROM, RL TI ATMOSPHERIC OPTICAL CALIBRATION SYSTEM FOR OUTDOOR TESTING OF PHOTOVOLTAIC DEVICES SO METROLOGIA LA English DT Article AB The Atmospheric Optical Calibration System (AOCS) was developed at the National Renewable Energy Laboratory for making real-time, terrestrially based measurements of selected optical properties of the atmosphere. The original application of the AOCS was to provide measurements of atmospheric optical conditions pertinent to outdoor photovoltaic (PV) device performance measurements. It addresses the dependence of outdoor PV test results on the characteristics of the incident solar radiation that are dependent on these constantly changing atmospheric optical conditions. This paper describes the AOCS, its calibration and its application to PV testing. Additional applications related to the measurement of atmospheric optical properties are also mentioned. RP CANNON, TW (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 24 TC 4 Z9 4 U1 1 U2 3 PU BUREAU INT POIDS MESURES PI SEVRES CEDEX PA B1 PM PAVILLION DE BRETUEIL, F-92312 SEVRES CEDEX, FRANCE SN 0026-1394 J9 METROLOGIA JI Metrologia PD OCT PY 1993 VL 30 IS 4 BP 409 EP 417 DI 10.1088/0026-1394/30/4/037 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA MN836 UT WOS:A1993MN83600038 ER PT J AU ZHANG, X JOY, DC AF ZHANG, X JOY, DC TI A SIMPLE SPECIMEN HOLDER FOR EBIC IMAGING ON THE HITACHI-S800 SO MICROSCOPY RESEARCH AND TECHNIQUE LA English DT Note C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP ZHANG, X (reprint author), UNIV TENNESSEE,ELECTRON MICROSCOPE FACIL,KNOXVILLE,TN 37996, USA. NR 1 TC 1 Z9 1 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 1059-910X J9 MICROSC RES TECHNIQ JI Microsc. Res. Tech. PD OCT 1 PY 1993 VL 26 IS 2 BP 182 EP 183 DI 10.1002/jemt.1070260214 PG 2 WC Anatomy & Morphology; Biology; Microscopy SC Anatomy & Morphology; Life Sciences & Biomedicine - Other Topics; Microscopy GA LU877 UT WOS:A1993LU87700013 PM 8241555 ER PT J AU BASKES, MI AF BASKES, MI TI UNTITLED SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Editorial Material C1 SANDIA NATL LABS,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD OCT PY 1993 VL 1 IS 5 BP U569 EP U569 PG 1 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA MP248 UT WOS:A1993MP24800001 ER PT J AU MACINNES, MA DICKSON, JA HERNANDEZ, RR LEARMONTH, D LIN, GY MUDGETT, JS PARK, MS SCHAUER, S REYNOLDS, RJ STRNISTE, GF YU, JY AF MACINNES, MA DICKSON, JA HERNANDEZ, RR LEARMONTH, D LIN, GY MUDGETT, JS PARK, MS SCHAUER, S REYNOLDS, RJ STRNISTE, GF YU, JY TI HUMAN ERCC5 CDNA-COSMID COMPLEMENTATION FOR EXCISION-REPAIR AND BIPARTITE AMINO-ACID DOMAINS CONSERVED WITH RAD PROTEINS OF SACCHAROMYCES-CEREVISIAE AND SCHIZOSACCHAROMYCES-POMBE SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID NUCLEAR TARGETING SEQUENCES; A XERODERMA-PIGMENTOSUM; DNA-REPAIR; MAMMALIAN-CELLS; NUCLEOTIDE-SEQUENCE; ESCHERICHIA-COLI; MOLECULAR CHARACTERIZATION; SECONDARY-STRUCTURE; COCKAYNES-SYNDROME; PLASMID DNA AB Several human genes related to DNA excision repair (ER) have been isolated via ER cross-species complementation (ERCC) of UV-sensitive CHO cells. We have now isolated and characterized cDNAs for the human ERCC5 gene that complement CHO UV135 cells. The ERCC5 mRNA size is about 4.6 kb. Our available cDNA clones are partial length, and no single clone was active for UV135 complementation. When cDNAs were mixed pairwise with a cosmid clone containing an overlapping 5'-end segment of the ERCC5 gene, DNA transfer produced UV-resistant colonies with 60 to 95% correction of UV resistance relative to either a genomic ERCC5 DNA transformant or the CHO AA8 progenitor cells. cDNA-cosmid transformants regained intermediate levels (20 to 45%) of ER-dependent reactivation of a UV-damaged pSVCATgpt reporter plasmid. Our evidence strongly implicates an in situ recombination mechanism in cDNA-cosmid complementation for ER. The complete deduced amino acid sequence of ERCC5 was reconstructed from several cDNA clones encoding a predicted protein of 1,186 amino acids. The ERCC5 protein has extensive sequence similarities, in bipartite domains A and B, to products of RAD repair genes of two yeasts, Saccharomyces cerevisiae RAD2 and Schizosaccharomyces pombe rad13. Sequence, structural, and functional data taken together indicate that ERCC5 and its relatives are probable functional homologs. A second locus represented by S. cerevisiae YKL510 and S. pombe rad2 genes is structurally distinct from the ERCC5 locus but retains vestigial A and B domain similarities. Our analyses suggest that ERCC5 is a nuclear-localized protein with one or more highly conserved helix-loop-helix segments within domains A and B. C1 MERCK RES LABS,DEPT MOLEC IMMUNOL,RAHWAY,NJ 07065. UNIV TEXAS,DEPT BIOL,AUSTIN,TX 78731. RP MACINNES, MA (reprint author), LOS ALAMOS NATL LAB,DIV LIFE SCI,M888,LOS ALAMOS,NM 87545, USA. NR 71 TC 46 Z9 48 U1 0 U2 0 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD OCT PY 1993 VL 13 IS 10 BP 6393 EP 6402 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA LY424 UT WOS:A1993LY42400045 PM 8413238 ER PT J AU MILLER, RM AF MILLER, RM TI NONTARGET AND ECOLOGICAL EFFECTS OF TRANSGENICALLY ALTERED DISEASE RESISTANCE IN CROPS - POSSIBLE EFFECTS ON THE MYCORRHIZAL SYMBIOSIS SO MOLECULAR ECOLOGY LA English DT Article DE DISEASE RESISTANCE; MYCORRHIZA; MYCORRHIZAL SUSCEPTIBILITY; NONTARGET EFFECTS; PR PROTEINS; TRANSGENIC PLANTS ID ALLIUM-PORRUM; COLONIZATION; DEPENDENCE; PLANTS; ROOTS AB The ability to increase crop disease resistance by using transgenic (TG) means has recently been demonstrated for several crops. The current TG procedures alter the temporal expression of transgene pathogenesis-related (PR) proteins, so that the usually inducible PR proteins are expressed constitutively in the foreign host. The constitutive expression of the transgene PR protein chitinase is believed to increase the host's nonspecific basic resistance to pathogens. A potential nontarget effect of constitutively expressing chitinase may be a decrease in the activity of beneficial microbes, especially vesicular-arbuscular mycorrhizal fungi. The decrease in activity of mycorrhizal fungi is related to reduced susceptibility of TG plant roots to colonization by these fungi, which is in turn associated with lysis of fungal cell walls by the constitutively expressed chitinase. An argument is presented that use of TG means to alter the temporal expression of PR proteins ignores a legacy of past evolutionary trade-offs in vascular plants. A major nontarget effect of expressing transgene chitinase is a reduction in the susceptibility of roots to colonization by mycorrhizal fungi. This reduction in mycorrhizal susceptibility occurs without alteration of the mycorrhizal dependence of the host on symbiont-supplied nutrients. Data are presented in support of this contention that demonstrate a strong negative association between host pathogen resistance and mycorrhizal colonization. An ecological consequence of reducing mycorrhizal colonization is a decrease in the soil's mycorrhizal propagule reserve that diminishes the next crop's production, especially under low-input cropping practices. A further consequence that has both ecological and evolutionary outcomes is the escape of the transgene for improved pathogen resistance into wild populations. By increasing a crop's disease resistance by TG means, we may inadvertently be creating a 'super weed' when the TG plant or the transgene escapes into wild relatives through hybridization. Hybridization of wild relatives with TG plants would be especially relevant for crops, such as sugar beet, rapeseed, and many modem cereal cultivars that have close relatives in the wild but have a relatively low requirement for symbiont supplied nutrients or are nondependent. RP MILLER, RM (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439, USA. NR 33 TC 8 Z9 8 U1 1 U2 12 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD OCT PY 1993 VL 2 IS 5 BP 327 EP 335 DI 10.1111/j.1365-294X.1993.tb00025.x PG 9 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ME921 UT WOS:A1993ME92100006 ER PT J AU ZALENSKY, AO YAU, P BRENEMAN, JW BRADBURY, EM AF ZALENSKY, AO YAU, P BRENEMAN, JW BRADBURY, EM TI THE ABUNDANT 19-KILODALTON PROTEIN ASSOCIATED WITH HUMAN SPERM NUCLEI THAT IS RELATED TO SEMINAL PLASMA ALPHA-INHIBINS SO MOLECULAR REPRODUCTION AND DEVELOPMENT LA English DT Article DE BASIC PROTEINS; SEMENOGELIN PROCESSING; SPERM HEAD ID SPERMATOZOA; SEQUENCE; SPERMIOGENESIS; FERTILIZATION; SEMENOGELIN; CHROMATIN; ANTIGENS; CLONING; CELLS AB A basic protein with a relative molecular mass of 19 kDa has been identified and isolated to purity from sonication-resistant, partially demembranized human sperm nuclei. Several criteria prove that this is the unique sperm-specific protein, which was previously thought to be a sperm/testis histone. Partial primary structure sequencing demonstrates homologies with human seminal alpha-inhibins and semenogelin. From the sequence and Western-blotting data with antibodies against basic seminal inhibin-like peptide, we propose that this 19-kD protein is a product of 52-kDa semenogelin processing. The 19-kDa protein was not found among seminal plasma proteins and may be protected from further cleavage into inhibin-like peptides by its association with the sperm head. Immunofluorescence data indicate its localization in the nuclear periphery, with preferential concentration at the acrosome calyx boundary. (C) 1993 Wiley-Liss, Inc. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87544. RP ZALENSKY, AO (reprint author), UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616, USA. NR 33 TC 13 Z9 13 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 1040-452X J9 MOL REPROD DEV JI Mol. Reprod. Dev. PD OCT PY 1993 VL 36 IS 2 BP 164 EP 173 DI 10.1002/mrd.1080360207 PG 10 WC Biochemistry & Molecular Biology; Cell Biology; Developmental Biology; Reproductive Biology SC Biochemistry & Molecular Biology; Cell Biology; Developmental Biology; Reproductive Biology GA LZ800 UT WOS:A1993LZ80000006 PM 8257566 ER PT J AU JUPEN, C ISLER, RC TRABERT, E AF JUPEN, C ISLER, RC TRABERT, E TI SOLAR IDENTIFICATIONS OF FE-X-FE-XIV BASED ON COMPARISON WITH BEAM-FOIL, TOKAMAK AND LASER-PRODUCED PLASMA SPECTRA SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ATOMIC DATA; LINE-IDENTIFICATION; PLASMAS; TECHNIQUES-SPECTROSCOPIC; SUN-FLARES; ULTRAVIOLET-STARS ID ISOELECTRONIC SEQUENCE; OSCILLATOR-STRENGTHS; ENERGY-LEVELS; CALCULATED WAVELENGTHS; ALLOWED 3-3; INTERCOMBINATION TRANSITIONS; IONS; NI; LINES; ANGSTROMS AB We report 42 new Fe X-Fe XIV lines identified from solar, beam-foil, tokamak and laser-produced plasma spectra. 19 of these have been found in solar spectra. We also report some new laboratory data confirming previous solar identifications. The lines are of 3s(2)3p(k)-3s(2)3p(k-1)3d and 3s(2)3p(k)-3s3p(k+1) types and lie between 169 and 5 1 0 angstrom. We also give a new value for the forbidden 3p3(S-4(3/2)-P-2(1/2)) transition of Fe XII. In all, we have determined 17 new energy levels in these ions with uncertainties of +/- 10 cm-1. C1 OAK RIDGE NATL LAB,DIV FUS ENERGY,OAK RIDGE,TN 37830. RUHR UNIV BOCHUM,W-4630 BOCHUM 1,GERMANY. RP JUPEN, C (reprint author), LUND UNIV,DEPT PHYS,SOLVEGATAN 14,S-22362 LUND,SWEDEN. NR 25 TC 58 Z9 58 U1 0 U2 0 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 OCT 1 PY 1993 VL 264 IS 3 BP 627 EP 635 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LZ508 UT WOS:A1993LZ50800013 ER PT J AU ECKELMEYER, KH AF ECKELMEYER, KH TI ENHANCING K-12 SCIENCE-EDUCATION - AN UPDATE SO MRS BULLETIN LA English DT Editorial Material C1 SANDIA NATL LABS,MRS GRASS ROOTS EDUC COMM,ALBUQUERQUE,NM 87185. RP ECKELMEYER, KH (reprint author), SANDIA NATL LABS,SCH PARTNERSHP PROGRAM,ALBUQUERQUE,NM 87185, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD OCT PY 1993 VL 18 IS 10 BP 75 EP 77 PG 3 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA MD776 UT WOS:A1993MD77600012 ER PT J AU FABER, V MOORE, JW CHEN, WYC AF FABER, V MOORE, JW CHEN, WYC TI CYCLE PREFIX DIGRAPHS FOR SYMMETRICAL INTERCONNECTION NETWORKS SO NETWORKS LA English DT Article AB Motivated by the study of large graphs with given degree and diameter, and the recent interest in the design of highly symmetric interconnection networks (e.g., the study of Cayley digraphs), we are led to the search for large vertex symmetric digraphs with given degree and diameter. The main result of this paper is the construction of a new class of vertex symmetric directed graphs, GAMMA(DELTA)(D) (DELTA greater-than-or-equal-to D) that have degree DELTA, diameter D, and (DELTA + 1)DELTA ... (DELTA - D + 2) vertices. The graphs GAMMA(DELTA)(D) are first found in the notation of Cayley coset digraphs. Then, we discover that they have a very simple representation in terms of sequences like the commonly studied networks such as the hypercube, de Bruijn graphs, and Kautz graphs. Based on the sequence representation, we give a simple shortest-path routing scheme. We also show that the average distance in our digraph GAMMA(DELTA)(D) is very close to its diameter D. As a consequence, it follows that the natural routing scheme, which is even simpler than the shortest-path routing, is nearly optimal on an average basis. (C) 1993 by John Wiley & Sons, Inc. RP FABER, V (reprint author), LOS ALAMOS NATL LAB, DIV COMP & COMMUN, MAIL STOP B265, LOS ALAMOS, NM 87545 USA. NR 21 TC 26 Z9 27 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0028-3045 EI 1097-0037 J9 NETWORKS JI Networks PD OCT PY 1993 VL 23 IS 7 BP 641 EP 649 DI 10.1002/net.3230230707 PG 9 WC Computer Science, Hardware & Architecture; Operations Research & Management Science SC Computer Science; Operations Research & Management Science GA LY522 UT WOS:A1993LY52200006 ER PT J AU FOWLER, JS VOLKOW, ND LOGAN, J SCHLYER, DJ MACGREGOR, RR WANG, GJ WOLF, AP PAPPAS, N ALEXOFF, D SHEA, C GATLEY, SJ DORFLINGER, E YOO, K MORAWSKY, L FAZZINI, E AF FOWLER, JS VOLKOW, ND LOGAN, J SCHLYER, DJ MACGREGOR, RR WANG, GJ WOLF, AP PAPPAS, N ALEXOFF, D SHEA, C GATLEY, SJ DORFLINGER, E YOO, K MORAWSKY, L FAZZINI, E TI MONOAMINE OXIDASE-B (MAO-B) INHIBITOR THERAPY IN PARKINSONS-DISEASE - THE DEGREE AND REVERSIBILITY OF HUMAN BRAIN MAO-B INHIBITION BY RO 19 6327 SO NEUROLOGY LA English DT Article ID POSITRON EMISSION TOMOGRAPHY; L-DEPRENYL; PET; L-DEPRENYL; LOCALIZATION; (-)DEPRENYL; SELEGILINE; DOPAMINE; TURNOVER; BINDING AB The possibility of slowing the progression of Parkinson's disease (PD) with inhibitors of monoamine oxidase B (MAO B) has stimulated the development of new MAO B inhibitor drugs. Ro 19 6327 is a highly selective inhibitor of MAO B currently under clinical investigation. We used positron emission tomography (PET) and the MAO B tracer [C-11]L-deprenyl to determine the degree and reversibility of human brain MAO B inhibition by Ro 19 6327 in six early Parkinson's disease patients who were treated with different doses of Ro 19 6327 (25 mg [n = 3], 50 mg [n = 2], and 100 mg [n = 1]; 0.34 to 1.4 mg/kg) every 12 hours for 1 week. Each patient had three PET scans to assess base-line MAO B activity, degree of trough inhibition, and reversibility. A control group of four elderly normal subjects was scanned twice to assess reproducibility of repeated measures. Four of the patients showed reduction of MAO B concentration to 1% to 7% of baseline on doses of 0.43 mg/kg or greater, and the remaining two at 0.34 mg/kg showed significant but incomplete inhibition (10% to 21% of baseline in the global region and in the thalamus, basal ganglia, and mesencephalon). Thus, 0.4 mg/kg or greater of Ro 19 6327 given every 12 hours is the minimum dose necessary to provide > 90% inhibition of brain MAO B in patients with early PD. Brain MAO B activity returned to baseline values by 36 hours after drug discontinuation. C1 HOFFMANN LA ROCHE INC, NUTLEY, NJ 07110 USA. NYU, NEW YORK, NY 10003 USA. RP BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. FU NINDS NIH HHS [NS 15380, NS 15638] NR 40 TC 75 Z9 75 U1 2 U2 7 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA TWO COMMERCE SQ, 2001 MARKET ST, PHILADELPHIA, PA 19103 USA SN 0028-3878 EI 1526-632X J9 NEUROLOGY JI Neurology PD OCT PY 1993 VL 43 IS 10 BP 1984 EP 1992 PG 9 WC Clinical Neurology SC Neurosciences & Neurology GA MC704 UT WOS:A1993MC70400021 PM 8413955 ER PT J AU JEFFRIES, DL LINK, SO KLOPATEK, JM AF JEFFRIES, DL LINK, SO KLOPATEK, JM TI CO2 FLUXES OF CRYPTOGAMIC CRUSTS .2. RESPONSE TO DEHYDRATION SO NEW PHYTOLOGIST LA English DT Article DE CRYPTOGAMIC CRUSTS; CO2 EXCHANGE; DEHYDRATION; MICROCOLEUS; SCYTONEMA ID RAMALINA-MENZIESII; WATER; EXCHANGE AB The carbon dioxide exchange of Microcoleus- and Scytonema-dominated cryptogamic crusts as related to dehydration was measured in the laboratory with a modified discrete sampling technique and infrared gas analysis. The dehydration curves predicted that carboxylation and dark respiration rates for both crust types would become zero at from 4 to 5 % water content (W) (approximately 16-23 % soil saturation), with the water contents at which the rates became zero significantly lower in the second treatment cycle than the first. The dehydration curves predicted that net photosynthesis rates would become zero at 6.7-11.2 % W (27-44 % soil saturation), with the water contents at which the rates became zero significantly higher in the second cycle of treatment than the first. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. ARIZONA STATE UNIV, DEPT BOT, TEMPE, AZ 85287 USA. RP JEFFRIES, DL (reprint author), UNIV OZARKS, DIV SCI & MATH, CLARKSVILLE, AR 72830 USA. NR 22 TC 24 Z9 28 U1 0 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0028-646X J9 NEW PHYTOL JI New Phytol. PD OCT PY 1993 VL 125 IS 2 BP 391 EP 396 DI 10.1111/j.1469-8137.1993.tb03891.x PG 6 WC Plant Sciences SC Plant Sciences GA MJ260 UT WOS:A1993MJ26000013 ER PT J AU POWELL, ET FONCK, RJ KAITA, R ASAKURA, N BELL, RE KAYE, SM KUGEL, HW LEBLANC, B LEVINTON, FM OKABAYASHI, M PAUL, SF ROBERTS, DW SESNIC, S TAKAHASHI, H AF POWELL, ET FONCK, RJ KAITA, R ASAKURA, N BELL, RE KAYE, SM KUGEL, HW LEBLANC, B LEVINTON, FM OKABAYASHI, M PAUL, SF ROBERTS, DW SESNIC, S TAKAHASHI, H TI CURRENT DISTRIBUTION MODIFICATION MEASUREMENTS IN THE PBX-M TOKAMAK SO NUCLEAR FUSION LA English DT Article ID ALCATOR-C TOKAMAK; HIGH-BETA-PLASMAS; IMAGE-RECONSTRUCTION; TOROIDAL PLASMAS; PINHOLE CAMERA; ASDEX TOKAMAK; CURRENT DRIVE; DISCHARGES; RESISTIVITY; TOMOGRAPHY AB Measurements of the flux surface shapes in a tokamak with a non-circular cross-section have been made using a tangentially viewing soft X ray pinhole camera. These measurements allowed the derivation of the value of the axial safety factor, q(0), and the shape of the plasma current profile, during equilibrium modification experiments. Two different equilibrium modification techniques were used: neutral beam current drive and plasma current ramp. In the neutral beam current drive experiment, tangential counter-injection was found to modify the equilibrium significantly, broadening the current profile and raising the value of q(0) above unity. In tangential co-injection discharges, q(0) values as low as 0.4 were observed. Reproduction of the measured q(0, t) using a radial current diffusion model strongly suggests there was a non-classical component to the cross-field current diffusion. A plasma current ramp of 2.5 MA/s was also shown to broaden the current profile; however, the value of q(0) was not altered. C1 UNIV WISCONSIN,DEPT NUCL ENGN & ENGN PHYS,MADISON,WI 53706. PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08544. FUS PHYS & TECHNOL,TORRANCE,CA. RP POWELL, ET (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 51 TC 8 Z9 8 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 OCT PY 1993 VL 33 IS 10 BP 1493 EP 1514 DI 10.1088/0029-5515/33/10/I08 PG 22 WC Physics, Fluids & Plasmas SC Physics GA MR375 UT WOS:A1993MR37500008 ER PT J AU NAPOLY, O CHIN, YH ZOTTER, B AF NAPOLY, O CHIN, YH ZOTTER, B TI A GENERALIZED-METHOD FOR CALCULATING WAKE POTENTIALS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We describe a generalized method to compute wake potentials created in axisymmetric structures. It relies on expressing the wake potentials, of any multipole order, as integrals over the e.m. fields along an arbitrary one-dimensional contour spanning the structure longitudinally. For perfectly conducting structures, the integration along the axis can then be replaced by choosing a contour beginning and ending on the beam tubes. Thus it generalizes the former method of calculating the wake potentials by integrating along a straight line at the beam tube radius. Its usefulness is illustrated with the computer code ABCI which permits calculation of wake potentials in structures extending to the inside of the beam tube radius, or having unequal beam tube radii at the two sides. C1 CERN,SL AP,CH-1211 GENEVA 23,SWITZERLAND. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP NAPOLY, O (reprint author), CENS,SEA,DAPNIA,F-919191 GIF SUR YVETTE,FRANCE. NR 7 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 255 EP 265 DI 10.1016/0168-9002(93)90782-D PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600001 ER PT J AU GARCZYNSKI, V AF GARCZYNSKI, V TI REMARKS ON DIFFERENTIAL-ALGEBRAIC APPROACH TO PARTICLE-BEAM OPTICS BY BERZ,M. SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID 5TH-ORDER; SYSTEMS AB The underlying mathematical structure of the differential algebraic approach of M. Berz to the particle beam optics is isomorphic to the familiar truncated polynomial algebra. Concrete examples of derivations in this algebra, consistent with the truncation operation, are given. RP GARCZYNSKI, V (reprint author), BROOKHAVEN NATL LAB,DEPT ACCELERATOR DEV,UPTON,NY 11973, USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 294 EP 298 DI 10.1016/0168-9002(93)90787-I PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600006 ER PT J AU WENDER, S SEESTROM, SJ MORRIS, CL AF WENDER, S SEESTROM, SJ MORRIS, CL TI A BEAM-CURRENT LIMITING DEVICE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A method for limiting beam currents in an accelerator to maximum values as low as several muA is described. This method relies on limiting the power supplied to a superconducting RF cavity in which the beam is accelerated. This technique may be useful in meeting health safety requirements at a facility such as LAMPF where low-intensity and high-intensity experimental areas are fed simultaneously with the same primary accelerator. RP WENDER, S (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 299 EP 300 DI 10.1016/0168-9002(93)90788-J PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600007 ER PT J AU KNAPP, DA MARRS, RE ELLIOTT, SR MAGEE, EW ZASADZINSKI, R AF KNAPP, DA MARRS, RE ELLIOTT, SR MAGEE, EW ZASADZINSKI, R TI A HIGH-ENERGY ELECTRON-BEAM ION-TRAP FOR PRODUCTION OF HIGH-CHARGE HIGH-Z IONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID EXCITATION CROSS-SECTIONS; DIELECTRONIC-RECOMBINATION; PRECISION-MEASUREMENT; IMPACT; TRANSITIONS; IONIZATION; SPECTRA; BARIUM; EBIT AB We have developed a new high-energy electron beam ion trap, the first laboratory source of low-energy, few-electron, high-Z ions. We describe the device and report measurements of its performance, including the electron beam diameter. current density and energy, and measurements of the ionization balance for several high-Z elements in the trap. This device opens up a wide range of possible experiments in atomic physics, plasma physics, and nuclear physics. RP KNAPP, DA (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 37 TC 108 Z9 108 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 305 EP 312 DI 10.1016/0168-9002(93)90790-O PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600009 ER PT J AU REEDER, RA DIETERLE, BD GREGORY, C SCHAEFER, F SCHUM, K STROSSMAN, W SMITH, D CHRISTOFEK, L JOHNSTON, K LOUIS, WC SCHILLACI, M VOLTA, M WHITE, DH WHITEHOUSE, D ALBERT, M YAMAN, K ATHANASSOPOULOS, C AUERBACH, LB HERMIDA, P WORKS, D AF REEDER, RA DIETERLE, BD GREGORY, C SCHAEFER, F SCHUM, K STROSSMAN, W SMITH, D CHRISTOFEK, L JOHNSTON, K LOUIS, WC SCHILLACI, M VOLTA, M WHITE, DH WHITEHOUSE, D ALBERT, M YAMAN, K ATHANASSOPOULOS, C AUERBACH, LB HERMIDA, P WORKS, D TI DILUTE SCINTILLATORS FOR LARGE-VOLUME TRACKING DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID NEUTRINO AB Dilute scintillation mixtures emit isotropic light for both fast and slow particles, but retain the Cherenkov light cone from fast particles. Large volume detectors using photomultipliers to reconstruct relativistic tracks will also be sensitive to slow particles if they are filled with these mixtures. Our data show that 0.03 g/l of b-PBD in mineral oil has a 2.4:1 ratio (in the first 12 ns) of isotropic light to Cherenkov light for positron tracks. The light attenuation length is greater than 15 m for wavelength above 400 nm, and the scintillation decay time is about 2 ns for the fast component. There is also a slow isotropic light component that is larger (relative to the fast component) for protons than for electrons. This effect allows particle identification by a technique similar to pulse shape discrimination. These features will be utilized in LSND, a neutrino detector at LAMPF. C1 UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. EMBRY RIDDLE AERONAUT UNIV,PRESCOTT,AZ 86301. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV PENN,PHILADELPHIA,PA 19104. TEMPLE UNIV,PHILADELPHIA,PA 19122. RP REEDER, RA (reprint author), UNIV NEW MEXICO,ALBUQUERQUE,NM 87131, USA. NR 18 TC 28 Z9 28 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 353 EP 366 DI 10.1016/0168-9002(93)90796-K PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600015 ER PT J AU AUBERT, B ABE, K CIOCIO, A COLAS, J DABA, A DOBRZYNSKI, L GHEZ, P HOSHI, Y ISO, H KADYK, J KIKUCHI, R KRYN, D LACOTTE, JC LAVOCAT, P MANSOULIE, B MARCHAND, D MENDIBURU, JP NEICHI, K PRIPSTEIN, M PRZYBYLSKI, G SALIN, P TEIGER, J WEBER, T WENZEL, WA YUTA, H AF AUBERT, B ABE, K CIOCIO, A COLAS, J DABA, A DOBRZYNSKI, L GHEZ, P HOSHI, Y ISO, H KADYK, J KIKUCHI, R KRYN, D LACOTTE, JC LAVOCAT, P MANSOULIE, B MARCHAND, D MENDIBURU, JP NEICHI, K PRIPSTEIN, M PRZYBYLSKI, G SALIN, P TEIGER, J WEBER, T WENZEL, WA YUTA, H TI STUDIES OF COMPENSATION OF IRON TMP AND LEAD TMP SAMPLING CALORIMETERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID URANIUM AB We present results of an extensive study of the response of a modular TMP hadron calorimeter to electron and pion beams from 5 to 150 GeV/c. The signal response ratio, e/-pi, was measured as a function of both the absorber material type and the ratio of absorber-to-TMP thicknesses. The absorbers were iron, lead and aluminum-clad lead. A detailed comparison of all the results to a Monte Carlo simulation is presented. The results with the lead absorber are consistent with those from a more limited study reported previously. C1 LBL,BERKELEY,CA. KYOTO UNIV,KYOTO 606,JAPAN. COLL FRANCE,CNRS,IN2P3,F-75231 PARIS 05,FRANCE. CENS,F-91190 GIF SUR YVETTE,FRANCE. TOHOKU GAKUIN UNIV,TAGAJO,JAPAN. TOHOKU UNIV,SENDAI,MIYAGI 980,JAPAN. RP AUBERT, B (reprint author), LAPP,CNRS,IN2P3,ANNECY,FRANCE. NR 14 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 383 EP 390 DI 10.1016/0168-9002(93)90798-M PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600017 ER PT J AU BERMAN, LE HART, M AF BERMAN, LE HART, M TI PRESERVING THE HIGH FINESSE OF X-RAY UNDULATOR BEAMS FROM PERFECT WATER-JET-COOLED DIAMOND MONOCHROMATORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ADAPTIVE CRYSTAL OPTICS; SYNCHROTRON AB A perfect single crystal of isotopically enriched diamond is shown to be an excellent X-ray monochromator for future undulator beams when jet-cooled with water. Unprecedented power densities, up to 260 W/mm2 with 63 W total X-ray power are provided by the focussed X-Tay beam from a 27 pole hybrid wiggler on beamline X25 at NSLS. Double crystal rocking curves have full widths at half maximum intensity of 3-4 arc sec which are determined by mounting strain and coolant pressure effects rather than the thermal strainfield. C1 UNIV MANCHESTER,DEPT PHYS,SCHUSTER LAB,MANCHESTER M13 9PL,LANCS,ENGLAND. RP BERMAN, LE (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 18 TC 15 Z9 15 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 617 EP 620 DI 10.1016/0168-9002(93)90829-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600048 ER PT J AU ATENCIO, LG MORRIS, CL SADLER, CP AF ATENCIO, LG MORRIS, CL SADLER, CP TI REDUCED MULTIPLE-SCATTERING USING THIN WINDOWS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Letter RP ATENCIO, LG (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 2 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1993 VL 334 IS 2-3 BP 643 EP 644 DI 10.1016/0168-9002(93)90833-4 PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LV786 UT WOS:A1993LV78600052 ER PT J AU WESTON, LW TODD, JH DERRIEN, H AF WESTON, LW TODD, JH DERRIEN, H TI NORMALIZATION AND MINIMUM VALUES OF THE PU-239 FISSION CROSS-SECTION SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID U-235 AB Measurements were carried out to accurately determine the shape of the fission cross section of Pu-239 down to 0.025 eV in order to determine a more accurate normalization for previously reported fission cross-section measurements from Oak Ridge National Laboratory at higher neutron energies. Also, experimental backgrounds were carefully studied to verify the cross section between resonances. Results indicate a 3.0 % higher normalization should have been used previously, and the low cross sections between resonances reported earlier were correct. New differential cross-section data were obtained from 0.002 to 100 eV. C1 JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. RP WESTON, LW (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 14 TC 2 Z9 2 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 OCT PY 1993 VL 115 IS 2 BP 164 EP 172 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA LZ865 UT WOS:A1993LZ86500006 ER PT J AU IKONOMOPOULOS, A TSOUKALAS, LH UHRIG, RE AF IKONOMOPOULOS, A TSOUKALAS, LH UHRIG, RE TI INTEGRATION OF NEURAL NETWORKS WITH FUZZY-REASONING FOR MEASURING OPERATIONAL PARAMETERS IN A NUCLEAR-REACTOR SO NUCLEAR TECHNOLOGY LA English DT Article DE ARTIFICIAL NEURAL NETWORKS; FUZZY REASONING; VIRTUAL MEASUREMENTS ID MULTILAYER FEEDFORWARD NETWORKS; MAPPINGS; COMPLEX AB A novel approach is described for measuring variables with operational significance in a complex system such as a nuclear reactor. The methodology is based on the integration of artificial neural networks with fuzzy reasoning. Neural networks are used to map dynamic time series to a set of user-defined linguistic labels called fuzzy values. The process takes place in a manner analogous to that of measurement. Hence, the entire procedure is referred to as virtual measurement and its software implementation as a virtual measuring device. An optimization algorithm based on information criteria and fuzzy algebra augments the process and assists in the identification of different states of the monitored parameter. The proposed technique is applied for monitoring parameters such as performance, valve position, transient type, and reactivity. The results obtained from the application of the neural network-fuzzy reasoning integration in a high power research reactor clearly demonstrate the excellent tolerance of the virtual measuring device to faulty signals as well as its ability to accommodate noisy inputs. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP IKONOMOPOULOS, A (reprint author), UNIV TENNESSEE,DEPT NUCL ENGN,KNOXVILLE,TN 37996, USA. NR 33 TC 20 Z9 21 U1 0 U2 1 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 OCT PY 1993 VL 104 IS 1 BP 1 EP 12 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA LY053 UT WOS:A1993LY05300001 ER PT J AU LEE, SY AF LEE, SY TI A NEW FLOODING CORRELATION DEVELOPMENT AND ITS CRITICAL HEAT-FLUX PREDICTIONS UNDER LOW AIR-WATER FLOW CONDITIONS IN SAVANNA RIVER SITE ASSEMBLY CHANNELS SO NUCLEAR TECHNOLOGY LA English DT Article DE FLOODING; COUNTERCURRENT FLOW; 2-PHASE FLOW ID CHF AB The upper limit to countercurrent flow, namely, flooding, is important to analyze the reactor coolability during an emergency cooling system (ECS) phase as a result of a large-break loss-of-coolant accident (LOCA) such as a double-ended guillotine break in the Savannah River Site (SRS) reactor system. During normal operation, the reactor coolant system utilizes downward flow through concentric heated tubes with ribs, which subdivide each annular channel into four subchannels. In this paper, a new flooding correlation has been developed based on the analytical models and literature data for adiabatic, steady-state, one-dimensional, air-water flow to predict flooding phenomenon in the SRS reactor assembly channel, which may have a countercurrent air-water flow pattern during the ECS phase. In addition, the correlation was benchmarked against the experimental data conducted under the Oak Ridge National Laboratory multislit channel, which is close to the SRS assembly geometry. Furthermore, the correlation has also been used as a constitutive relationship in a new two-component two-phase thermal-hydraulics code FLOWTRAN-TF, which has been developed for a detailed analysis of SRS reactor assembly behavior during LOCA scenarios. Finally, the flooding correlation was applied to the predictions of critical heat flux, and the results were compared with the data taken by the SRS heat transfer laboratory under a single annular channel with ribs and a multiannular prototypic test rig. RP LEE, SY (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER TECHNOL CTR,AIKEN,SC, USA. NR 18 TC 2 Z9 2 U1 0 U2 1 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 OCT PY 1993 VL 104 IS 1 BP 64 EP 73 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA LY053 UT WOS:A1993LY05300005 ER PT J AU SMITH, MS WOOD, DH DRISCHLER, JD AF SMITH, MS WOOD, DH DRISCHLER, JD TI AN ASSESSMENT OF LIQUID-METAL CENTRIFUGAL PUMPS AT 3 FAST-REACTORS SO NUCLEAR TECHNOLOGY LA English DT Article DE CENTRIFUGAL PUMPS; FAST REACTORS; LIQUID SODIUM AB The results of an analysis using data reports submitted to the Centralized Reliability Data Organization (CREDO) to predict the onset of the wearout life period for large sodium centrifugal pumps is described. For CREDO data collection and analysis purposes, a ''mechanical pump'' includes the pumping unit, its driver, and the coupling between the two. Statistical data were compiled from event reports received from three fast reactors: the Experimental Breeder Reactor II (EBR-II) and the Fast Flux Test Facility (FFTF) in the United States and the JOYO Experimental Fast Reactor operated by the Power Reactor and Nuclear Fuel Development Corporation of Japan. Cumulative event rates were calculated for the investigated pumps at each facility and for the entire population. For all pumps, the event rate was computed as 34.4 event/million operating hours with 5 and 95 % one-sided confidence limits of 26.3 and 44.4 event/million operating hours, respectively. The cumulative event rates for EBR-II, FFTF, and JOYO were computed as 30.0, 32.4, and 40.6 event/million pump operating hours, respectively. Results from EBR-II indicate that there is a definite time-dependent relationship between event rates and pump age; the common event mode at EBR-II is pump binding or seizing due to the buildup of sodium deposits in the vicinity of the lower labyrinth seal. There is no indication from FFTF that the six centrifugal pumps have reached the end of their useful life, these pumps have been event free for their last 40 000 operating hours. Following a 50 000-h event-free operating period at JOYO, bearings in the secondary pumps required additional unscheduled maintenance. However, there is no indication that these pumps have entered into the wearout life period; more data are required to draw any such conclusion. RP SMITH, MS (reprint author), OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,POB 2008,MS 6363,OAK RIDGE,TN 37831, USA. NR 5 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 OCT PY 1993 VL 104 IS 1 BP 118 EP 127 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA LY053 UT WOS:A1993LY05300009 ER PT J AU CHAR, DH QUIVEY, JM CASTRO, JR KROLL, S PHILLIPS, T AF CHAR, DH QUIVEY, JM CASTRO, JR KROLL, S PHILLIPS, T TI HELIUM-IONS VERSUS IODINE 125 BRACHYTHERAPY IN THE MANAGEMENT OF UVEAL MELANOMA - A PROSPECTIVE, RANDOMIZED, DYNAMICALLY BALANCED TRIAL SO OPHTHALMOLOGY LA English DT Article; Proceedings Paper CT 1992 ANNUAL MEETING OF THE AMERICAN-ACADEMY-OF-OPHTHALMOLOGY CY NOV, 1992 CL DALLAS, TX SP AMER ACAD OPHTHALMOL ID PLAQUE THERAPY; CHOROIDAL MELANOMA; PROTON-BEAM; FOLLOW-UP; IRRADIATION; I-125; RADIOTHERAPY; COMPLICATIONS; EYE; RECURRENCE AB Purpose: Optimal radiation therapy for uveal melanoma is uncertain, and the relative efficacies of radioactive plaques and charged particles are unclear. Methods: The authors prospectively studied helium-ion irradiation and iodine 125 (I-125) brachytherapy in a randomized, dynamically balanced trial. Of the 184 patients who met the eligibility criteria, 86 were treated with helium ions and 98 with I-125 brachytherapy. Results: No patients with uveal melanoma had a history of systemic malignancy. Tumors were less than 15 mm in maximum diameter and less than 10 mm in thickness. A minimum tumor dose of 70 GyE was delivered to the tumor apex. There was a significantly higher local recurrence rate after I-125 brachytherapy than after helium-ion irradiation. Enucleations occurred more frequently after brachytherapy (relative risk = 1.99; 95% confidence interval, 0.78-5.78). More anterior segment complications occurred after helium-ion irradiation. To date, there has been no measurable impact on survival. Conclusions: Most uveal melanomas can be managed with radiation with retention of the eye. There was better tumor control with helium-ion irradiation; however, there were more anterior segment complications. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF SAN FRANCISCO,DEPT OPHTHALMOL,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT RADIAT ONCOL,SAN FRANCISCO,CA 94143. FU NCI NIH HHS [NCI CA 19138]; NEI NIH HHS [EYO 7504] NR 39 TC 131 Z9 133 U1 0 U2 2 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0161-6420 J9 OPHTHALMOLOGY JI Ophthalmology PD OCT PY 1993 VL 100 IS 10 BP 1547 EP 1554 PG 8 WC Ophthalmology SC Ophthalmology GA MA307 UT WOS:A1993MA30700027 PM 8414414 ER PT J AU RU, P MOLONEY, JV INDIK, R KOCH, SW CHOW, WW AF RU, P MOLONEY, JV INDIK, R KOCH, SW CHOW, WW TI MICROSCOPIC MODELING OF BULK AND QUANTUM-WELL GAAS-BASED SEMICONDUCTOR-LASERS SO OPTICAL AND QUANTUM ELECTRONICS LA English DT Article ID LINEWIDTH ENHANCEMENT FACTOR; HIGHLY EXCITED SEMICONDUCTORS; DIRECT-GAP SEMICONDUCTORS; OPTICAL-PROPERTIES; STABILITY AB The dynamical behaviour of Fabry-Perot type semiconductor lasers is modelled, including the relevant many-body Coulomb effects of the excited carriers. Conditions are given under which a parametrization of the full model is possible, allowing simple analytic relations for focal gain, refractive index and linewidth enhancement factor. The parameters of the simplified model are uniquely determined by the microscopic theory and have to be optimized for the respective operating conditions. The theory is evaluated for bulk and quantum-well GaAs active material and a variety of laser structures, including strongly and weakly index-guided structures, as well as purely guided single- and twin-stripe lasers. C1 UNIV ARIZONA,CTR OPT SCI,TUCSON,AZ 85721. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP RU, P (reprint author), UNIV ARIZONA,DEPT MATH,TUCSON,AZ 85721, USA. NR 23 TC 9 Z9 9 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0306-8919 J9 OPT QUANT ELECTRON JI Opt. Quantum Electron. PD OCT PY 1993 VL 25 IS 10 BP 675 EP 693 DI 10.1007/BF00430557 PG 19 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA MF233 UT WOS:A1993MF23300002 ER PT J AU SCOTT, SL ESPENSON, JH CHEN, WJ AF SCOTT, SL ESPENSON, JH CHEN, WJ TI ELECTRON-TRANSFER REACTIONS OF 17-ELECTRON AND 19-ELECTRON ORGANOMETALLIC RADICALS, CPW(CO)3 AND CPW(CO)3PPH3 SO ORGANOMETALLICS LA English DT Article ID HALOGEN ATOM TRANSFER; CARBONYL RADICALS; LIGAND SUBSTITUTION; CATION RADICALS; COMPLEXES; OXIDATION; ION; PHOTOCHEMISTRY; MECHANISM; KINETICS AB Laser flash photolysis of [CpW(CO)3]2 was carried out at 490 nm, where the primary photoprocess gives a 17-electron radical, CpW(CO)3. The metal radical acts as both an electron donor and acceptor. The radical reduces ferrocenium ions (k = [1.89(4)] X 10(7) L mol-1 s-1) and benzoquinone (k = [2.7(1)] X 10(7) L mol-1 s-1) at 23-degrees-C in acetonitrile. Triphenylphosphine accelerates the reaction of the tungsten radical with ferrocenium ions, suggesting the formation of the more strongly reducing 19-electron radical CpW(CO)3PPh3. It reacts with ferrocenium ions: k = 3 X 10(9) L mol-1 s-1. The base-induced disproportionation of CpW(CO)3 was used to evaluate binding constants for CpW(CO)3 and PPh3 (K = 6 +/- 1 L mol-1) and pyridine (K = 0.16 +/- 0.04 L mol-1). Also, the CpW(CO)3 radical oxidizes decamethylferrocene (2.2 X 10(8)L mol-1 s-1) and N,N,N',N'-tetramethylphenylenediamine (2.6 X 10(7) L mol-1 s-1). In this system there is a secondary process responsible for the re-reduction of TMPD.+. We suggest the rapid formation of the radical anion [CpW(CO)3]2.-, presumed to be a powerful electron donor, to account for back-electron transfer, but this has not been proved. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 33 TC 21 Z9 21 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD OCT PY 1993 VL 12 IS 10 BP 4077 EP 4084 DI 10.1021/om00034a048 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA MC322 UT WOS:A1993MC32200048 ER PT J AU MONTANARI, A ASARO, F MICHEL, HV KENNETT, JP AF MONTANARI, A ASARO, F MICHEL, HV KENNETT, JP TI IRIDIUM ANOMALIES OF LATE EOCENE AGE AT MASSIGNANO (ITALY), AND ODP SITE-689B (MAUD-RISE, ANTARCTIC) SO PALAIOS LA English DT Article ID NORTH-AMERICAN MICROTEKTITES; OLIGOCENE BOUNDARY; NEW-JERSEY; TEKTITE FRAGMENTS; CONTINENTAL-SLOPE; STRATIGRAPHY; BARBADOS; GUBBIO; GEOCHEMISTRY; EXTINCTIONS AB Iridium anomalies of Late Eocene age are here reported in sequences from northern Italy and Weddell Sea, Antarctic. We have analyzed 270 samples of marly limestones from the Eocene/Oligocene boundary stratotype section at Massignano, Italy, ranging from 35.6 to 34.5 Ma (NP 18 Zone to NP19/20 Zone). We discovered a distinct Ir peak of 156 +/- 19 parts per trillion (ppt) in the lower calcareous nannofossil NP19/20 Zone, corresponding to the mid-lower part of foraminiferal P16 Zone, and the top of magnetic Chron 16n2. The age of this Ir anomaly derived from several dated volcanic ashes found in the same section is 35.7 +/- 0.4 Ma. A minor Ir anomaly also occurs within Chron 16r1 (approximately 35.55 Ma). Two small Ir anomalies were previously found in the lower part of Chron 13r (approximately 34.8 and 34.6 Ma) in the Contessa section near Gubbio (about 80 km west of Massignano), but were not found in equivalent stratigraphic intervals in this section. A total of 410 samples of Late Eocene age analyzed in ODP 689B (Maud Rise, Weddell Sea, Antarctic), also reveal a distinct Ir peak (156 +/- 10 ppt). This occurs in sediments of normal remanent magnetization that can be interpreted either as Chron 16n1 (approximately 35.5 Ma), or as Chron 15n (approximately 35.0 Ma). This stratigraphic ambiguity results from scarcity of useful microfossil datums in this interval. Moreover, the last occurrence of Isthmolithus recurvus and the first occurrence of Globigerinatheka index, which are the only two datums defining a biostratigraphic zonation for the Late Eocene in ODP 689B, are apparently diachronous with the Massignano stratotype section. The principal Ir anomaly in ODP 689B seems 0.2 Ma, or 0.5 Ma younger than that of the Massignano section, depending on which alternative magnetostratigraphic interpretation is employed. The apparent diachroneity of microfossil datums and a lack of magnetostratigraphic data do not provide adequate stratigraphic resolution for correlation of Ir anomalies in Massignano or ODP 689B sections with those found in several Late Eocene sequences in the equatorial Indian and Pacific, and the Caribbean-Gulf of Mexico region. Nevertheless, multiple Ir anomalies as documented in this work, and differences in chemical composition among Late Eocene north American tektites, microtektites, and crystal-bearing spherules, the latter often associated with an iridium anomaly, suggest a sequence of closely spaced extraterrestrial impacts occurred during a million year period between 35.7 and 34.7 Ma. C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF SANTA BARBARA,INST MARINE SCI,SANTA BARBARA,CA 93106. UNIV CALIF SANTA BARBARA,DEPT GEOL SCI,SANTA BARBARA,CA 93106. NR 70 TC 81 Z9 81 U1 0 U2 6 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 SN 0883-1351 J9 PALAIOS JI Palaios PD OCT PY 1993 VL 8 IS 5 BP 420 EP 437 DI 10.2307/3515017 PG 18 WC Geology; Paleontology SC Geology; Paleontology GA ME770 UT WOS:A1993ME77000003 ER PT J AU BALATSKY, AV AF BALATSKY, AV TI SUPERCONDUCTING INSTABILITY IN A NON-FERMI LIQUID - SCALING APPROACH SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article AB The superconducting instability in a non-Fermi liquid in dimensions d > 1 is considered. For a particular form of the single particle spectral function with homogeneous scaling A(LAMBDAk, LAMBDAomega) = LAMBDA(alpha)A(k, omega) it is shown that the pair susceptibility is also a scaling function of temperature with power defined by alpha. We find three different regimes depending on the scaling constant. Bardeen-Cooper-Schrieffer result is recovered for alpha = -1 and it corresponds to a marginal scaling of the coupling constant. For alpha > -1 the superconducting transition happens above some critical coupling. In the opposite case of alpha < -1 for any fixed coupling the system undergoes a transition at low temperatures. Possible implications for theories of high-T(c) with a superconducting transition driven by interlayer Josephson tunnelling are discussed. C1 LANDAU INST THEORET PHYS,MOSCOW,RUSSIA. RP BALATSKY, AV (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 4 TC 19 Z9 19 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD OCT PY 1993 VL 68 IS 4 BP 251 EP 256 DI 10.1080/09500839308242421 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA LZ525 UT WOS:A1993LZ52500012 ER PT J AU DOBSON, JE AF DOBSON, JE TI COMMENTARY - A CONCEPTUAL-FRAMEWORK FOR INTEGRATING REMOTE-SENSING, GIS, AND GEOGRAPHY SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID INFORMATION-SYSTEMS; SENSED DATA; MODELS; ISSUES RP DOBSON, JE (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 29 TC 13 Z9 20 U1 0 U2 0 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD OCT PY 1993 VL 59 IS 10 BP 1491 EP 1496 PG 6 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA MB704 UT WOS:A1993MB70400003 ER PT J AU CINCO, RM MACINNIS, JM GREENBAUM, E AF CINCO, RM MACINNIS, JM GREENBAUM, E TI THE ROLE OF CARBON-DIOXIDE IN LIGHT-ACTIVATED HYDROGEN-PRODUCTION BY CHLAMYDOMONAS-REINHARDTII SO PHOTOSYNTHESIS RESEARCH LA English DT Article DE ALGAE; CALVIN CYCLE; CARBON DIOXIDE; HYDROGEN; HYDROGENASE; LIGHT-ACTIVATED; OXYGEN ID BICARBONATE AB Light-activated hydrogen and oxygen evolution as a function of CO2 concentration in helium were measured for the unicellular green alga Chlamydomonas reinhardtii. The concentrations were 58, 30, 0.8 and 0 ppm CO2. The objective of these experiments was to study the differential affinity of CO2/HCO3- for their respective Photosystem II and Calvin cycle binding sites vis-A-vis photoevolution of molecular oxygen and the competitive pathways of hydrogen photoevolution and CO2 photoassimilation. The maximum rate of hydrogen evolution occurred at 0.8 PPM CO2, whereas the maximum rate of oxygen evolution occurred at 5 8 ppm CO2. The key result of this work is that the rate of photosynthetic hydrogen evolution can be increased by, at least partially, satisfying the Photosystem II CO2/HCO3- binding site requirement without fully activating the Calvin-Benson CO2 reduction pathway. Data are presented which plot the rates of hydrogen and oxygen evolution as functions of atmospheric CO2 concentration in helium and light intensity. The stoichiometric ratio of hydrogen to oxygen changed from 0.1 at 58 ppm to approximately 2.5 at 0.8 ppm. A discussion of partitioning of photosynthetic reductant between the hydrogen/hydrogenase and Calvin-Benson cycle pathways is presented. C1 OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831. NR 20 TC 29 Z9 29 U1 2 U2 5 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 OCT PY 1993 VL 38 IS 1 BP 27 EP 33 DI 10.1007/BF00015058 PG 7 WC Plant Sciences SC Plant Sciences GA MK647 UT WOS:A1993MK64700004 PM 24317827 ER PT J AU PAUL, DM FORGAN, EM CUBITT, R LEE, SL YETHIRAJ, M MOOK, HA AF PAUL, DM FORGAN, EM CUBITT, R LEE, SL YETHIRAJ, M MOOK, HA TI THE FLUX-LINE-LATTICE IN HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICA B LA English DT Article; Proceedings Paper CT WORKSHOP ON THE USE OF NEUTRONS AND X-RAYS IN THE STUDY OF MAGNETISM CY JAN 21-23, 1993 CL GRENOBLE, FRANCE SP INST LAUE LANGEVIN, EUROPEAN SYNCHROTRON RADIAT FACIL ID HIGH-TC SUPERCONDUCTORS; SINGLE-CRYSTAL YBA2CU3O7-DELTA; MAGNETIC PENETRATION DEPTH; ANGLE NEUTRON-SCATTERING; II SUPERCONDUCTORS; VORTEX LATTICE; MIXED STATE; DIFFRACTION AB This article reviews the use of neutron small-angle scattering to determine the spatial distribution of the magnetic field within the bulk of a high-temperature superconductor. Results will be presented for experiments using single crystals of YBa2Cu3O7. The influence of pinning and anisotropy on the experimental data will be discussed together with the anomalous temperature dependence of the integrated intensity. Future directions for such work will be suggested. C1 UNIV BIRMINGHAM,SUPERCONDUCT RES GRP,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP PAUL, DM (reprint author), UNIV WARWICK,DEPT PHYS,COVENTRY CV4 7AL,W MIDLANDS,ENGLAND. RI cubitt, robert/B-9408-2008; Lee, Stephen/G-9791-2016 OI Lee, Stephen/0000-0002-2020-3310 NR 20 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1993 VL 192 IS 1-2 BP 70 EP 78 DI 10.1016/0921-4526(93)90109-J PG 9 WC Physics, Condensed Matter SC Physics GA ME992 UT WOS:A1993ME99200008 ER PT J AU AEPPLI, G HAYDEN, SM MOOK, HA MASON, TE TAYLOR, AD CLAUSEN, KN PERRING, TG CHEONG, SW FISK, Z RYTZ, D AF AEPPLI, G HAYDEN, SM MOOK, HA MASON, TE TAYLOR, AD CLAUSEN, KN PERRING, TG CHEONG, SW FISK, Z RYTZ, D TI FROM INSULATOR TO METAL WITH HOT AND COLD NEUTRONS SO PHYSICA B LA English DT Article; Proceedings Paper CT WORKSHOP ON THE USE OF NEUTRONS AND X-RAYS IN THE STUDY OF MAGNETISM CY JAN 21-23, 1993 CL GRENOBLE, FRANCE SP INST LAUE LANGEVIN, EUROPEAN SYNCHROTRON RADIAT FACIL ID MAGNETIC FLUCTUATIONS; SPIN; ANTIFERROMAGNET; LA2-XSRXCUO4; RELAXATION; SCATTERING; DYNAMICS; LA2CUO4; MODEL AB This paper is a short review of magnetic neutron scattering experiments on La2-x(Sr, Ba)xCuO4. Special emphasis is given to measurements of the spin waves using hot-source triple-axis and spallation-source time-of-flight spectroscopies, magnetic fluctuations near the metal-insulator transition, Fermi surface effects and the dramatic impact of superconductivity on the magnetic response function. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV BRISTOL,HH WILLS PHYS LAB,BRISTOL BS8 1TL,AVON,ENGLAND. RISO NATL LAB,ROSKILDE,DENMARK. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. SANDOZ LTD,CH-4002 BASEL,SWITZERLAND. RP AEPPLI, G (reprint author), AT&T BELL LABS,600 MT AVE,MURRAY HILL,NJ 07974, USA. RI Hayden, Stephen/F-4162-2011; Mason, Thomas/M-5809-2014 OI Hayden, Stephen/0000-0002-3209-027X; Mason, Thomas/0000-0003-1880-3971 NR 27 TC 6 Z9 6 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1993 VL 192 IS 1-2 BP 103 EP 108 DI 10.1016/0921-4526(93)90112-J PG 6 WC Physics, Condensed Matter SC Physics GA ME992 UT WOS:A1993ME99200011 ER PT J AU FELCHER, GP AF FELCHER, GP TI MAGNETIC DEPTH PROFILING STUDIES BY POLARIZED NEUTRON REFLECTION SO PHYSICA B LA English DT Article; Proceedings Paper CT WORKSHOP ON THE USE OF NEUTRONS AND X-RAYS IN THE STUDY OF MAGNETISM CY JAN 21-23, 1993 CL GRENOBLE, FRANCE SP INST LAUE LANGEVIN, EUROPEAN SYNCHROTRON RADIAT FACIL ID SUPERCONDUCTOR YBA2CU3O7-X; SURFACE MAGNETISM; FIELD PENETRATION; SUPERLATTICES; FILMS; MULTILAYERS; SCATTERING; LAYERS; MAGNETORESISTANCE; REFLECTOMETER AB A review is given of the role of polarized neutron reflectivity (PNR) in measuring the magnetic profile close to the surface and in thin films of superconductors and magnetic materials. For type I and type II superconductors PNR provided a new and direct determination of the penetration depth. For very thin ferromagnetic films PNR was able to determine the absolute value of the magnetic moments. In magnetic superlattices, formed by the alternation of ferromagnetic layers and nonmagnetic spacers, PNR was used to confirm the basic magnetic structure as well as to determine the direction of the magnetic moments of the individual layers. In addition to reflectivity, forward magnetic scattering may very well extend the usefulness of PNR to the case of laterally dishomogeneous systems. RP FELCHER, GP (reprint author), ARGONNE NATL LAB,MSD-223,ARGONNE,IL 60439, USA. NR 58 TC 73 Z9 73 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1993 VL 192 IS 1-2 BP 137 EP 149 DI 10.1016/0921-4526(93)90115-M PG 13 WC Physics, Condensed Matter SC Physics GA ME992 UT WOS:A1993ME99200014 ER PT J AU THURSTON, TR HELGESEN, G HILL, JP GIBBS, D GAULIN, BD SHIRANE, G AF THURSTON, TR HELGESEN, G HILL, JP GIBBS, D GAULIN, BD SHIRANE, G TI X-RAY AND NEUTRON-SCATTERING STUDIES OF MAGNETIC CRITICAL FLUCTUATIONS IN HOLMIUM SO PHYSICA B LA English DT Article; Proceedings Paper CT WORKSHOP ON THE USE OF NEUTRONS AND X-RAYS IN THE STUDY OF MAGNETISM CY JAN 21-23, 1993 CL GRENOBLE, FRANCE SP INST LAUE LANGEVIN, EUROPEAN SYNCHROTRON RADIAT FACIL ID CRITICAL-BEHAVIOR; RESONANCE; POLARIZATION; DIFFRACTION; TRANSITIONS AB We describe measurements of the magnetic critical fluctuations of holmium by X-ray scattering techniques. The X-ray results are compared to those obtained in neutron scattering experiments performed on the same sample. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4L8,ONTARIO,CANADA. RI Hill, John/F-6549-2011; Piper, Walter/B-7908-2009 NR 25 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1993 VL 192 IS 1-2 BP 177 EP 181 DI 10.1016/0921-4526(93)90118-P PG 5 WC Physics, Condensed Matter SC Physics GA ME992 UT WOS:A1993ME99200017 ER PT J AU FISCHER, DA MOODENBAUGH, AR XU, YW AF FISCHER, DA MOODENBAUGH, AR XU, YW TI OXYGEN K NEAR-EDGE X-RAY-ABSORPTION SPECTROSCOPY OF LA2-XMXCUO4 (M=CA, SR AND BA) - X-DEPENDENCE OF HOLE STATE DENSITY SO PHYSICA C LA English DT Article ID ELECTRONIC-STRUCTURE; FINE-STRUCTURE; LA2-XSRXCUO4; CA AB Fluorescence-yield oxygen K near-edge X-ray spectroscopy was utilized as a bulk-sensitive method to determine the hole state density of La2-xMxCuO4. Pre-edge features have been measured for M=Sr, 0 less-than-or-equal-to x less-than-or-equal-to 0.40, M=Ba, 0 less-than-or-equal-to x less-than-or-equal-to 0.25, and M=Ca, 0 less-than-or-equal-to x less-than-or-equal-to 0.10. These features occur just above the Fermi level at approximately 530 and approximately 528 eV, the 528 eV peak being assigned to holes in the oxygen 2p band. The intensities and energies of these peaks were determined as a function of composition x. Results are qualitatively similar among M=Sr, Ba and Ca. For x less-than-or-equal-to 0.15 the magnitude of the 528 eV peak is linear in x. In the overdoped region, x>0.15, M=Sr, the magnitude begins to saturate. C1 BROOKHAVEN NATL LAB,DIV MAT SCI,UPTON,NY 11973. RP FISCHER, DA (reprint author), NATL INST STAND & TECHNOL,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. OI Moodenbaugh, Arnold/0000-0002-3415-6762 NR 18 TC 5 Z9 5 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 OCT 1 PY 1993 VL 215 IS 3-4 BP 279 EP 285 DI 10.1016/0921-4534(93)90226-G PG 7 WC Physics, Applied SC Physics GA MA672 UT WOS:A1993MA67200005 ER PT J AU KRISHNARAJ, P LELOVIC, M EROR, NG BALACHANDRAN, U AF KRISHNARAJ, P LELOVIC, M EROR, NG BALACHANDRAN, U TI SYNTHESIS AND MICROSTRUCTURE OF BI1.8PB0.4SR2CA2.2CU3OX OBTAINED FROM FREEZE-DRIED PRECURSORS SO PHYSICA C LA English DT Article ID CA-CU-O; SUPERCONDUCTING PHASE; 2223 PHASE; TC PHASE; SYSTEM; POWDERS; GROWTH AB Amorphous precursor powders for Bi1.8Pb0.4Sr2Ca2.2Cu3Ox(2223) were prepared by a freeze-drying process incorporating a splat-freezing step. The critical parameters affecting the drying process are discussed. The freeze-dried powders have high reactivity and led to essentially phase pure 2223 phase formation in 12 h. The microstructure of the 2223 shows fine particles of 2201 in the matrix. The grain boundaries of the 2223 grains appear to be clean, leading to good intergrain contact between 2223 grains. C1 ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439. RP KRISHNARAJ, P (reprint author), UNIV PITTSBURGH,DEPT MAT SCI & ENGN,PITTSBURGH,PA 15261, USA. NR 20 TC 26 Z9 27 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 OCT 1 PY 1993 VL 215 IS 3-4 BP 305 EP 312 DI 10.1016/0921-4534(93)90230-N PG 8 WC Physics, Applied SC Physics GA MA672 UT WOS:A1993MA67200009 ER PT J AU DUNFORD, RW BERRY, HG CHURCH, DA HASS, M LIU, CJ RAPHAELIAN, MLA ZABRANSKY, BJ CURTIS, LJ LIVINGSTON, AE AF DUNFORD, RW BERRY, HG CHURCH, DA HASS, M LIU, CJ RAPHAELIAN, MLA ZABRANSKY, BJ CURTIS, LJ LIVINGSTON, AE TI FORBIDDEN TRANSITIONS IN ONE-ELECTRON AND 2-ELECTRON NICKEL SO PHYSICAL REVIEW A LA English DT Article ID 2-PHOTON DECAY-RATES; RADIATIVE DECAY; ISOELECTRONIC SEQUENCE; HELIUMLIKE IONS; HYDROGENIC IONS; MUONIC ATOMS; 22S1/2 STATE; 23S1 STATE; LIFETIME; ARGON AB We describe measurements of the lifetimes of metastable states in one- and two-electron nickel ions. The 2 S-1(1/2) level in one-electron nickel was found to have a lifetime of 217.1(1.8) ps, in agreement with a theoretical calculation of 215.45 ps. The lifetimes of the 2 S-1(0) and 2 P-3(2) levels in two-electron nickel were found to be 156.1(1.6) and 70(3) ps, respectively, in agreement with the theoretical results of 154.3(0.5) and 70.6 ps. We also studied the phenomenon of hyperfine quenching of the He-like 2 P-3(0) level by comparing decay curves for the isotopes Ni-61 and Ni-58. The lifetime of the 2 P-3(0) level in Ni-61(26+) was found to be 470(50) ps, in agreement with a theoretical prediction. The measurements were carried out using the beam-foil time-of-flight technique with a fast beam of highly charged nickel ions. We discuss the handling of systematic effects in the measurements, including the study of yrast cascades following the beam-foil interaction. C1 UNIV TOLEDO, DEPT PHYS & ASTRON, TOLEDO, OH 43606 USA. UNIV NOTRE DAME, DEPT PHYS, NOTRE DAME, IN 46556 USA. RP ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439 USA. NR 88 TC 28 Z9 28 U1 0 U2 1 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 OCT PY 1993 VL 48 IS 4 BP 2729 EP 2745 DI 10.1103/PhysRevA.48.2729 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700026 ER PT J AU CSANAK, G CARTWRIGHT, DC DAPAIXAO, FJ AF CSANAK, G CARTWRIGHT, DC DAPAIXAO, FJ TI MANY-BODY THEORY OF ELECTRON-SCATTERING BY EXCITED ATOMIC TARGETS - FUNDAMENTAL FORMULAS SO PHYSICAL REVIEW A LA English DT Article ID TOTAL CROSS-SECTIONS; IMPACT EXCITATION; SODIUM ATOMS; SUPERELASTIC SCATTERING; INELASTIC-SCATTERING; STATES; HELIUM; PARAMETERS; 23S; 21S AB A many-body theory of electron-impact excitation out of excited atomic states is presented. After the fundamental equations and formulas of the general theory are given, first- and second-order approximations are introduced. In the case of the first-order theory, detailed analytical formulas are also developed. The physical interpretation of the first- and second-order theories are presented with the aid of Feynman-type diagrams. Following a discussion of initial- and final-state effects, the many-body theory is also related to the distorted-wave approximation. C1 UNIV ESTADUAL CAMPINAS, BR-13100 CAMPINAS, SP, BRAZIL. RP LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 88 TC 9 Z9 9 U1 0 U2 0 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 OCT PY 1993 VL 48 IS 4 BP 2811 EP 2827 DI 10.1103/PhysRevA.48.2811 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700034 ER PT J AU WONG, KL BEIERSDORFER, P CHEN, MH MARRS, RE REED, KJ SCOFIELD, JH VOGEL, DA ZASADZINSKI, R AF WONG, KL BEIERSDORFER, P CHEN, MH MARRS, RE REED, KJ SCOFIELD, JH VOGEL, DA ZASADZINSKI, R TI ELECTRON-IMPACT IONIZATION OF LITHIUM-LIKE IONS - TI-19+, V-20+, CR-21+, MN-22+, AND FE-23+ SO PHYSICAL REVIEW A LA English DT Article ID HIGHLY CHARGED IONS; TIME-RESOLVED SPECTROSCOPY; CROSS-SECTIONS; DIELECTRONIC RECOMBINATION; RATE COEFFICIENTS; TOKAMAK PLASMAS; RADIATIVE RECOMBINATION; EXCITATION; BEAM; POLARIZATION AB The Livermore electron-beam ion trap has been used to measure cross sections for electron-impact ionization of lithiumlike Ti, V, Cr, Mn, and Fe. The measurements were made using two variations of an x-ray technique that correlates ionization events with dielectronic-recombination photons. The cross sections were determined at one energy corresponding to approximately 2.3 times threshold. Ionization cross sections are measured (i) relative to the theoretical cross section for radiative recombination onto the n = 2 shell for lithiumlike ions and (ii) relative to the theoretical cross section for direct excitation of the lithiumlike line q[1s2s(3S)2p P-2(3/2) --> 1s(2)2s S-2(1/2)]. The uncertainties in the ionization cross sections are estimated to be about 10% from the experiment together with a systematic uncertainty from the choice of normalization, which is 3% for radiative recombination and 10% for direct excitation. Good agreement is found with relativistic distorted-wave calculations. RP WONG, KL (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 31 TC 26 Z9 26 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 OCT PY 1993 VL 48 IS 4 BP 2850 EP 2859 DI 10.1103/PhysRevA.48.2850 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700038 ER PT J AU DEVENEY, EF KESSEL, QC FULLER, RJ REAVES, MP BELLANTONE, RA SHAFROTH, SM JONES, N AF DEVENEY, EF KESSEL, QC FULLER, RJ REAVES, MP BELLANTONE, RA SHAFROTH, SM JONES, N TI PROJECTILE-AUGER-ELECTRON SPECTRA OF C-3+ FOLLOWING 12 MEV COLLISIONS WITH HE TARGETS SO PHYSICAL REVIEW A LA English DT Article ID IONS; EXCITATION; H2 AB Major features of the projectile-Auger-electron spectrum in the 220-300-eV energy range that are observed following I-MeV/u collisions of Li-like carbon ions with helium target atoms are shown to be composites of closely spaced.Auger lines that result from autoionizing (AI) transitions of excited C3+ configurations formed during the collision. From calculations of Auger-electron energies and Auger yields, a simulation of the Auger-electron spectrum is constructed and it is shown that a superposition of AI decays from LS-coupled doublets of the doubly excited C3+ 1s2snl configurations with n = 2, 3, 4, ..., infinity, reproduces most of the observed structure. Remarks are made concerning relative intensities of the Auger peaks with respect to excitation and population probabilities, particularly in the case of the two doublet terms of the 1s2s2p configuration. An Auger peak of almost-equal-to 265.0 eV in the projectile frame that could not be accounted for in the 1s2snl series is attributed to a possible two-electron process in which one of the projectile electrons is ionized and another is excited. C1 UNIV N CAROLINA, DEPT PHYS & ASTRON, CHAPEL HILL, NC 27599 USA. OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37831 USA. UNIV CONNECTICUT, INST MAT SCI, STORRS, CT 06269 USA. RP UNIV CONNECTICUT, DEPT PHYS, STORRS, CT 06269 USA. NR 22 TC 2 Z9 2 U1 0 U2 1 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 OCT PY 1993 VL 48 IS 4 BP 2926 EP 2933 DI 10.1103/PhysRevA.48.2926 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700044 ER PT J AU ELZA, BK RITCHIE, B AF ELZA, BK RITCHIE, B TI USE OF TIME-DEPENDENT WAVE-PACKET THEORY IN ELECTRON-MOLECULE SCATTERING SO PHYSICAL REVIEW A LA English DT Article AB Time-dependent wave-packet theory [B. Ritchie, Phys. Rev. A 45, R4207 (1992)] is applied to electron-molecule scattering. The Schrodinger equation is solved in time and space on a numerical grid, thus avoiding use of basis-set expansions. A plane-wave-centered, Gaussian wave packet is propagated through the region of the potential. Once the wave packet has passed outside the range of the potential, the differential cross section is calculated directly from the multidimensional wave function by use of the Huygens-Fresnel integral from optics. RP ELZA, BK (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 1993 VL 48 IS 4 BP 2940 EP 2945 DI 10.1103/PhysRevA.48.2940 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700046 ER PT J AU SIMIONOVICI, A DIETRICH, DD KEVILLE, R COWAN, T BEIERSDORFER, P CHEN, MH BLUNDELL, SA AF SIMIONOVICI, A DIETRICH, DD KEVILLE, R COWAN, T BEIERSDORFER, P CHEN, MH BLUNDELL, SA TI SOFT-X-RAY SPECTROSCOPY OF DELTA-N = 0, N = 3 TRANSITIONS IN HIGHLY STRIPPED LEAD SO PHYSICAL REVIEW A LA English DT Article ID ENERGY-LEVELS; ISOELECTRONIC SEQUENCE; RESONANCE TRANSITION; SELF-ENERGY; IONS; 3S-3P; N=3 AB We report on n = 3 to n = 3 soft-x-ray transitions from the highest nuclear charge (Z = 82) Na-like ions yet obtained. The results are tied to accurate calculations including screened QED contributions and confirm theoretical trends observed by Kim et al. [Phys. Rev. A 44, 148 (1991)]. Weak Ne-like and Mg-like lines are observed in an accelerator-based experiment in the energy range near 800 eV and compared to multiconfiguration Dirac-Fock calculations. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RI Cowan, Thomas/A-8713-2011 OI Cowan, Thomas/0000-0002-5845-000X NR 22 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 1993 VL 48 IS 4 BP 3056 EP 3061 DI 10.1103/PhysRevA.48.3056 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MC717 UT WOS:A1993MC71700062 ER PT J AU SODERLIND, P ERIKSSON, O WILLS, JM JOHANSSON, B AF SODERLIND, P ERIKSSON, O WILLS, JM JOHANSSON, B TI LOCAL-MOMENT COLLAPSE IN COMPRESSED SAMARIUM METAL SO PHYSICAL REVIEW B LA English DT Article ID HIGH-PRESSURE PHASE; CRYSTAL-STRUCTURE; ACTINIDE METALS; BRILLOUIN-ZONE; SPECIAL POINTS; CERIUM METAL; BAND; SYSTEMS; GPA AB We present theoretical evidence that the recently observed ultra-high-pressure phase in samarium metal is a delocalized 4f-electron system with an itinerant spin moment of approximately 4mu(B). By comparing the total energy (at T = 0) of the localized fcc phase and the delocalized bct phase we conclude that Sm metal will undergo a delocalization of the 4f shell in the Mbar pressure range. This is consistent with the previous experimental observation of an fcc-->bct transition at approximately 1 Mbar. Furthermore, our calculations show that the correct crystal structure (bct) is obtained only for delocalized 4f states, and the calculated c/a ratio (1.70) compares well with experimental data (1.76). C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP SODERLIND, P (reprint author), UNIV UPPSALA,DEPT PHYS,BOX 530,S-75105 UPPSALA,SWEDEN. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 31 TC 11 Z9 11 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 13 BP 9212 EP 9215 DI 10.1103/PhysRevB.48.9212 PG 4 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600002 ER PT J AU SODERLIND, P ERIKSSON, O WILLS, JM BORING, AM AF SODERLIND, P ERIKSSON, O WILLS, JM BORING, AM TI ELASTIC-CONSTANTS OF CUBIC F-ELECTRON ELEMENTS - THEORY SO PHYSICAL REVIEW B LA English DT Article ID GROUND-STATE PROPERTIES; CRYSTAL-STRUCTURE; TRANSITION-METALS; LATTICE-DYNAMICS; PHASE-TRANSITION; ACTINIDE METALS; CERIUM; LANTHANUM; PRESSURE; BAND AB We report first-principles calculations of the elastic constants of cubic f-electron elements: fcc La (stable at elevated temperatures), alpha-Ce, Th, bcc U (stable at elevated temperatures), bcc Np (stable at elevated temperatures), bcc Pu, and fcc Pu (both these phases of Pu are also stable at elevated temperatures). The zero-temperature calculations employed the linear muffin-tin orbitals method. The computed elastic constants of fcc La and Th are found to be in rather good agreement with experiment. The tetragonal shear constant of the cubic phases of U, Np, and Pu is negative, showing that at zero temperature the bcc or fcc structure is unstable for these systems. The stabilization of cubic structures in these materials must therefore have a significant temperature-dependent contribution, and the elasticity of these materials must also depend heavily on this temperature-dependent contribution. The calculated data of alpha-Ce is a prediction, since no experimental data are available, and may therefore serve as encouragement for experimental work. C1 LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP SODERLIND, P (reprint author), UNIV UPPSALA,DEPT PHYS,CONDENSED MATTER THEORY GRP,BOX 530,S-75105 UPPSALA,SWEDEN. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 48 TC 36 Z9 36 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 OCT 1 PY 1993 VL 48 IS 13 BP 9306 EP 9320 DI 10.1103/PhysRevB.48.9306 PG 15 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600014 ER PT J AU BARBEE, TW AF BARBEE, TW TI METASTABILITY OF ATOMIC PHASES OF NITROGEN SO PHYSICAL REVIEW B LA English DT Article ID TOTAL-ENERGY; SOLID NITROGEN; DISSOCIATION; TRANSFORMATION; PRESSURES; GRAPHITE; DIAMOND; MBAR AB The metastability of a recently proposed candidate for a polymeric structure for nitrogen is examined using linear response theory to calculate the phonon dispersion throughout the Brillouin zone. It is found that the structure is mechanically stable at pressures below 360 GPa. In contrast, nitrogen in the simple cubic structure is found to be unstable over the same pressure range. Calculations of Raman- and infrared-active phonon frequencies are presented for the metastable phase. RP BARBEE, TW (reprint author), LAWRENCE LIVERMORE NATL LAB,L-299,LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 23 TC 41 Z9 41 U1 1 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 OCT 1 PY 1993 VL 48 IS 13 BP 9327 EP 9330 DI 10.1103/PhysRevB.48.9327 PG 4 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600017 ER PT J AU SVARE, I BORSA, F TORGESON, DR MARTIN, SW AF SVARE, I BORSA, F TORGESON, DR MARTIN, SW TI CORRELATION-FUNCTIONS FOR IONIC MOTION FROM NMR RELAXATION AND ELECTRICAL-CONDUCTIVITY IN THE GLASSY FAST-ION CONDUCTOR (LI2S)0.56(SIS2)0.44 SO PHYSICAL REVIEW B LA English DT Article ID NUCLEAR-SPIN RELAXATION; DISORDERED SOLIDS; AC CONDUCTION; HYDROGEN DIFFUSION; MODEL; LI2SIS3 AB The Li-7 NMR spin-lattice relaxation and the electrical conductivity in the typical glassy fast-ion conductor (Li2S)0.56(SiS2)0.44 are discussed from models of Li+ ionic motion with distributions of activation energies, as well as from stretched-exponential time-correlation functions. The measured correlation times from the two effects differ by two orders of magnitude, and the derived distributions are shifted greatly relative to each other. We relate the great differences to percolation around the high barriers in the distribution. We present a phenomenological theory that yields good quantitative fits to the observed NMR relaxation with a Gaussian distribution, and to the conductivity and related dielectric properties with the continuous-time random-walk model and the same Gaussian truncated at the percolation limit. This correlates the two effects in a simple and effective way; both time-correlation functions can be calculated approximately from the distributions, and even the dc conductivity can be calculated from the NMR results. The present approach is discussed and compared with previously proposed models to explain the anomalies in ac electrical-conductivity and NMR relaxation rates in glassy fast-ion conductors. C1 UNIV PAVIA,DEPT PHYS,I-27100 PAVIA,ITALY. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP SVARE, I (reprint author), UNIV TRONDHEIM,DEPT PHYS,N-7034 TRONDHEIM,NORWAY. NR 29 TC 74 Z9 74 U1 0 U2 15 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 OCT 1 PY 1993 VL 48 IS 13 BP 9336 EP 9344 DI 10.1103/PhysRevB.48.9336 PG 9 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600019 ER PT J AU BLYTH, RIR JOYCE, JJ ARKO, AJ CANFIELD, PC ANDREWS, AB FISK, Z THOMPSON, JD BARTLETT, RJ RISEBOROUGH, P TANG, J LAWRENCE, JM AF BLYTH, RIR JOYCE, JJ ARKO, AJ CANFIELD, PC ANDREWS, AB FISK, Z THOMPSON, JD BARTLETT, RJ RISEBOROUGH, P TANG, J LAWRENCE, JM TI TEMPERATURE-INVARIANT VALENCE-BAND-4F PHOTOEMISSION FEATURES IN THE HEAVY-FERMION COMPOUND YBAL3 SO PHYSICAL REVIEW B LA English DT Article ID RARE-EARTH-METALS; PHOTOELECTRON-SPECTRA; KONDO RESONANCE; ANDERSON MODEL; 4F STATES; CERIUM; DEPENDENCE; YB; INCONSISTENCIES; SPECTROSCOPY AB A high-resolution photoemission (PES) study of the heavy-fermion compound YbAl3 has been undertaken to test the qualitative and quantitative predictions of the single-impurity model. Corroborating data on YbAgCu4 and YbCu2Si2 are also presented. For Yb-based heavy fermions the model predicts a fully occupied Kondo resonance so that its width, intensity, and temperature dependence should be directly accessible by PES. Due to the existence of temperature- and/or contamination-dependent surface features, which are not dealt with by the model, a rigorous normalization and curve-fitting procedure was required to extract the bulk 4f line shape. For the particular temperature cycling method employed by us, we do not observe any temperature dependence in the peak that had been previously identified as the Kondo resonance. We find that both the binding energy and width of this peak are significantly larger than theory predicts. It is also found that the trends in 4f line shape and surface shift between YbAl3 and LuAl3 are consistent with the trends seen between the 4f core levels of elemental Yb and Lu. Similar results are also found in YbCu2Si2 and YbAgCu4 for similar cycling methods. Recent observations of temperature dependence in these systems are most easily understood in terms of surface phenomena. C1 POLYTECH INST NEW YORK,BROOKLYN,NY 11201. UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. RP BLYTH, RIR (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Riseborough, Peter/D-4689-2011; Canfield, Paul/H-2698-2014 NR 33 TC 51 Z9 51 U1 1 U2 8 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 OCT 1 PY 1993 VL 48 IS 13 BP 9497 EP 9507 DI 10.1103/PhysRevB.48.9497 PG 11 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600040 ER PT J AU RIERA, J DAGOTTO, E AF RIERA, J DAGOTTO, E TI CLUSTER DIAGONALIZATION IN SYSTEMATICALLY EXPANDED HILBERT-SPACES - APPLICATION TO MODELS OF CORRELATED ELECTRONS SO PHYSICAL REVIEW B LA English DT Article ID 2-DIMENSIONAL HUBBARD-MODEL; CONFIGURATION-INTERACTION CALCULATIONS; HIGH-TC SUPERCONDUCTIVITY; SYSTEMS; ANTIFERROMAGNET; OXIDES AB A method of cluster diagonalization in a systematically expanded Hilbert space is described. We discuss some applications of this procedure to models of high-T(c) superconductors, like the t-J model and the one- and three-band Hubbard models in two dimensions. The results obtained with this method are compared against results obtained with other techniques dealing with truncated Hilbert spaces. The relation between this method of diagonalization in a reduced Hilbert space, and perturbation theory and variational techniques is also discused. C1 VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. FLORIDA STATE UNIV,CTR MAT RES & TECHNOL,DEPT PHYS,TALLAHASSEE,FL 32306. FLORIDA STATE UNIV,SUPERCOMP COMPUTAT RES INST,TALLAHASSEE,FL 32306. RP RIERA, J (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831, USA. RI Riera, Jose/A-1234-2008 OI Riera, Jose/0000-0003-4546-1137 NR 38 TC 17 Z9 17 U1 2 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 OCT 1 PY 1993 VL 48 IS 13 BP 9515 EP 9523 DI 10.1103/PhysRevB.48.9515 PG 9 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600042 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 X-RAY SPECULAR-REFLECTIVITY STUDY OF THE LIQUID-VAPOR DENSITY PROFILE OF HE-4 SO PHYSICAL REVIEW B LA English DT Article ID SURFACE-PROPERTIES; HELIUM FILMS; SCATTERING; SILICON; ATOMS; ROUGH AB The helium liquid-vapor interfacial density profile has been measured with x-ray specular reflectivity. Measurements were performed on thick films of helium adsorbed onto atomically flat silicon substrates. Both the amplitude and the phase of the complex scattering amplitude of the helium-vapor interface were obtained from measured interference between reflections from the helium liquid-vapor interface and the silicon-helium interface. Films whose thickness varied from 15 angstrom to 220 angstrom over a range of temperatures from 1.1 K to 3.0 K were studied. At T = 1.13 K the film thickness is 215 angstrom and the interfacial width is 9.2+/-1 angstrom. No significant variation was seen in the interfacial widths measured at temperatures between 1.1 K and 1.8 K. Analysis of these measurements indicates that the interface is asymmetric, with the decay of the density into the vapor having the sharper falloff. The zero-K interfacial width extrapolated from the finite-temperature measurements with a quantized capillary-wave theory is 7.6(-2)+1 angstrom. C1 HARVARD UNIV, DEPT PHYS, CAMBRIDGE, MA 02138 USA. HARVARD UNIV, DIV APPL SCI, CAMBRIDGE, MA 02138 USA. BAR ILAN UNIV, DEPT PHYS, IL-52100 RAMAT GAN, ISRAEL. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. NR 49 TC 39 Z9 39 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 13 BP 9644 EP 9659 DI 10.1103/PhysRevB.48.9644 PG 16 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600059 ER PT J AU WANG, ZL BRYNESTAD, J KROEGER, DM SUN, YR THOMPSON, JR WILLIAMS, RK AF WANG, ZL BRYNESTAD, J KROEGER, DM SUN, YR THOMPSON, JR WILLIAMS, RK TI GRAIN-BOUNDARY CHEMISTRY AND WEAK-LINK BEHAVIOR OF POLYCRYSTALLINE YBA2CU4O8 SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; CRITICAL CURRENTS; YBA2CU3O7-DELTA; BICRYSTALS; DECOMPOSITION; HOLES; CU AB Magnetic-susceptibility and grain-boundary-chemistry data were obtained on dense YBa2Cu4O8 (Y 1:2:4) samples. Transmission-electron microscopy showed that the grain boundaries were free of second phases and the dislocation density was low. Cation content, oxygen composition, and hole density were determined by the combined techniques of nanoprobe energy-dispersive x-ray spectroscopy and electron-energy-loss spectroscopy. A total of 25 pairs of grains was analyzed and the results indicated that grain boundary and bulk compositions do not differ. The relative orientations of the crystallites were determined, and the results show that a wide variety of misorientations was sampled. Almost all of the grain boundaries were fully oxygenated and there are no hole deficiencies, but the magnetic-susceptibilty measurements showed that the material is granular weak linked. These results indicate that Y 1:2:4 is a material in which clean, stoichiometric boundaries still form weak links. C1 UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP WANG, ZL (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. RI Wang, Zhong Lin/E-2176-2011 OI Wang, Zhong Lin/0000-0002-5530-0380 NR 37 TC 16 Z9 16 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 13 BP 9726 EP 9734 DI 10.1103/PhysRevB.48.9726 PG 9 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600070 ER PT J AU WANG, ZN SHI, DL AF WANG, ZN SHI, DL TI THERMALLY ACTIVATED FLUX AVALANCHES IN SINGLE-CRYSTALS OF HIGH-T(C) SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID SELF-ORGANIZED CRITICALITY AB We have experimentally investigated long-time (> 10 h) magnetic relaxation in single crystals of Bi2Sr2CaCu2Ox and YBa2Cu8Ox at wide ranges of temperature and field. We have found that the flux motion in single crystals of high-T(c) superconductors exhibits two distinctly different behaviors at a wide regime of driving force. At large driving force, the flux motion is dominated by thermally activated avalanches, which can be described by a so-called self-organized criticality theory. At small driving force, however, the avalanche effect is significantly reduced, and the flux motion is characterized by slow creep which can be described by the Anderson-Kim model. Therefore, there is a dynamic crossover between the flux avalanches and a pure thermally activated regime in high-T(c) superconductors. C1 IIT,DEPT PHYS,CHICAGO,IL 60616. RP WANG, ZN (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 16 TC 24 Z9 28 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 OCT 1 PY 1993 VL 48 IS 13 BP 9782 EP 9787 DI 10.1103/PhysRevB.48.9782 PG 6 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600077 ER PT J AU MALIK, SK TAKEYA, H GSCHNEIDNER, KA AF MALIK, SK TAKEYA, H GSCHNEIDNER, KA TI OBSERVATION OF SUPERCONDUCTIVITY IN LARHSB SO PHYSICAL REVIEW B LA English DT Note ID KONDO-LATTICE SYSTEM; MAGNETIC-SUSCEPTIBILITY; HEAT-CAPACITY; COMPOUND; RESISTIVITY; CEPDSN AB Low-temperature magnetic-susceptibility and heat-capacity measurements on the ternary intermetallic compound LaRhSb reveal that this compound is superconducting with transition temperature of 2.1 K. The specific-heat jump at T(c) disappears in an applied field of 0.5 Tesla. The electronic-specific-heat coefficient gamma is found to be 7.7 mJ/mole K2, and the Debye temperature THETA(D) to be 252 K. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP MALIK, SK (reprint author), TATA INST FUNDAMENTAL RES,BOMBAY 400005,INDIA. NR 11 TC 20 Z9 20 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 OCT 1 PY 1993 VL 48 IS 13 BP 9858 EP 9860 DI 10.1103/PhysRevB.48.9858 PG 3 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600092 ER PT J AU LI, Q SHIBUTANI, K SUENAGA, M SHIGAKI, I OGAWA, R AF LI, Q SHIBUTANI, K SUENAGA, M SHIGAKI, I OGAWA, R TI CRITICAL FLUCTUATIONS IN THE MAGNETIZATION OF BI2SR2CACU2O8 NEAR THE H(C2)(T) LINE SO PHYSICAL REVIEW B LA English DT Note ID HIGH-TEMPERATURE SUPERCONDUCTORS; II SUPERCONDUCTORS; FIELD; TRANSITION; BI2SR2CA2CU3O10 AB The magnetization measurements on Bi2Sr2CaCu2O8 single crystals with H parallel to the c axis are presented to show that the critical fluctuations in the magnetization near the H(c2)(T) line can be well studied within the two-dimensional nonperturbative scaling theory developed by Tesanovic et al. By using this scaling theory and basic thermodynamic arguments, we obtained the Ginzburg-Landau parameter kappa (congruent-to 115) and dH(c2)/dT (congruent-to -2.7 T/K) near T(c) for this material. In addition, we found that these derived parameters are in good agreement with those determined from the study of reversible magnetization in an intermediate field at low temperature. C1 KOBE STEEL LTD,CTR SUPERCOND & CRYOGEN TECHNOL,NISHI KU,KOBE 65122,JAPAN. RP LI, Q (reprint author), BROOKHAVEN NATL LAB,FAC MAT SCI,UPTON,NY 11973, USA. NR 17 TC 57 Z9 57 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 OCT 1 PY 1993 VL 48 IS 13 BP 9877 EP 9880 DI 10.1103/PhysRevB.48.9877 PG 4 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600097 ER PT J AU DRESSEL, M BRUDER, S GRUNER, G CARLSON, KD WANG, HH WILLIAMS, JM AF DRESSEL, M BRUDER, S GRUNER, G CARLSON, KD WANG, HH WILLIAMS, JM TI LOW-TEMPERATURE MICROWAVE SURFACE IMPEDANCE OF THE CONVENTIONAL ORGANIC SUPERCONDUCTOR KAPPA-(BEDT-TTF)2CU(NCS)2 SO PHYSICAL REVIEW B LA English DT Note ID MAGNETIC PENETRATION DEPTH; NMR RELAXATION; CRITICAL-FIELD; BEDT-TTF; (BEDT-TTF)2CU(NCS)2; BEHAVIOR; 10-K; HEAT AB We have performed measurements of the microwave surface impedance Z(S) = R(S) + iX(S) of the organic superconductor kappa-(BEDT-TTF)2Cu(NCS)2 down to T = 0.8 K. The reactance X(S), and therefore the penetration depth lambda, exhibits no temperature dependence for T << T(c). This result is in full agreement with calculations of the BCS ground state and gives no indication of unconventional pairing. Furthermore, we have evaluated the complex conductivity sigma = sigma1 + isigma2 and find a pronounced peak in sigma1 below T(c) which can be identified as a coherence peak. C1 UNIV CALIF LOS ANGELES,CTR SOLID STATE SCI,LOS ANGELES,CA 90024. ARGONNE NATL LAB,DIV CHEM & MAT SCI,ARGONNE,IL 60439. RP DRESSEL, M (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024, USA. RI Dressel, Martin/D-3244-2012 NR 29 TC 27 Z9 27 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 OCT 1 PY 1993 VL 48 IS 13 BP 9906 EP 9909 DI 10.1103/PhysRevB.48.9906 PG 4 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600105 ER PT J AU SCHWARTZ, J NAKAMAE, S RABAN, GW HEUER, JK WU, S WAGNER, JL HINKS, DG AF SCHWARTZ, J NAKAMAE, S RABAN, GW HEUER, JK WU, S WAGNER, JL HINKS, DG TI LARGE CRITICAL-CURRENT DENSITY IN NEUTRON-IRRADIATED POLYCRYSTALLINE HGBA2CUO4+DELTA SO PHYSICAL REVIEW B LA English DT Note ID FLUX PINNING ENHANCEMENT; SINGLE-CRYSTALS AB The effects of neutron irradiation on the superconducting properties of HgBa2CuO4+delta are reported. Enhancements in the magnetization critical current density (J(c)), as calculated by the Bean model, vary with magnetic field and temperature and range from 1-2 orders of magnitude. Large values (J(c) > 10(4) A/cm2) are obtained above (0.5 T, 77 K) and (3 T, 50 K) after irradiation. A large shift in the irreversibility line toward higher field and temperature is also reported. These results demonstrate that HgBa2CuO4+delta is not intrinsically limited to low current density and may become a technologically important compound. C1 UNIV ILLINOIS,DEPT NUCL ENGN,URBANA,IL 61801. UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,DIV MAT SCI,ARGONNE,IL 60439. RP SCHWARTZ, J (reprint author), UNIV ILLINOIS,SCI & TECHNOL CTR SUPERCOND,URBANA,IL 61801, USA. RI Schwartz, Justin/D-4124-2009 OI Schwartz, Justin/0000-0002-7590-240X NR 13 TC 26 Z9 26 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 OCT 1 PY 1993 VL 48 IS 13 BP 9932 EP 9934 DI 10.1103/PhysRevB.48.9932 PG 3 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600112 ER PT J AU NORMAN, MR MCMULLAN, GJ NOVIKOV, DL FREEMAN, AJ AF NORMAN, MR MCMULLAN, GJ NOVIKOV, DL FREEMAN, AJ TI EFFECT OF STRUCTURE ON THE ELECTRONIC DENSITY-OF-STATES OF DOPED LANTHANUM CUPRATE SO PHYSICAL REVIEW B LA English DT Note ID SUPERCONDUCTIVITY; LA2-XBAXCUO4 AB We present a series of detailed band calculations on the various structural phases of doped lanthanum cuprate: HTT, LTO, and LTT. The LTO distortion is shown to have little effect on the electronic density of states (DOS). A fit to the pressure dependence of the superconducting transition temperature indicates that only 2.5% of the DOS is affected by the HTT --> LTO transition. The LTT distortion also has little effect on the DOS for the experimental value of the octahedral tilt angle. Larger tilt angles, though, lead to a dramatic change in the DOS. C1 UNIV CAMBRIDGE,CAVENDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND. NORTHWESTERN UNIV,DEPT PHYS & ASTRON,EVANSTON,IL 60208. RP NORMAN, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Norman, Michael/C-3644-2013 NR 9 TC 20 Z9 20 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 OCT 1 PY 1993 VL 48 IS 13 BP 9935 EP 9937 DI 10.1103/PhysRevB.48.9935 PG 3 WC Physics, Condensed Matter SC Physics GA MC116 UT WOS:A1993MC11600113 ER PT J AU CHEN, JM SIMONS, JK TAN, KH ROSENBERG, RA AF CHEN, JM SIMONS, JK TAN, KH ROSENBERG, RA TI CORRELATION BETWEEN INTERATOMIC DISTANCES AND THE X-RAY-ABSORPTION NEAR-EDGE STRUCTURE OF SINGLE-CRYSTAL SAPPHIRE SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; CORE EXCITONS; TETRAHEDRAL COORDINATION; AMORPHOUS-SILICON; AL2O3; AL; PHOTOEMISSION; CORUNDUM; ALUMINUM; ELEMENTS AB The high-resolution Al L-edge x-ray-absorption near-edge structure from single-crystal sapphire has been recorded by measuring the total-electron yield and x-ray-fluorescence yield with synchrotron radiation. The edge structures up to 11 eV from the absorption edge are assigned in terms of the transitions of Al 2p electrons to empty levels using molecular-orbital calculations. The post-edge features between 11 and 60 eV above the Al L23 absorption edge were found to correlate very well with the interatomic distances from the absorbing atom to its neighboring atoms as predicted by the multiple-scattering model. C1 UNIV WISCONSIN,DEPT CHEM,MADISON,WI 53706. CANADIAN SYNCHROTRON RADIAT FACIL,STOUGHTON,WI 53589. ARGONNE NATL LAB,ARGONNE,IL 60439. RP CHEN, JM (reprint author), SYNCHROTRON RADIAT RES CTR,HSINCHU 30077,TAIWAN. RI Rosenberg, Richard/K-3442-2012 NR 38 TC 15 Z9 15 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 OCT 1 PY 1993 VL 48 IS 14 BP 10047 EP 10051 DI 10.1103/PhysRevB.48.10047 PG 5 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800009 ER PT J AU FOSTER, CM LI, Z GRIMSDITCH, M CHAN, SK LAM, DJ AF FOSTER, CM LI, Z GRIMSDITCH, M CHAN, SK LAM, DJ TI ANHARMONICITY OF THE LOWEST-FREQUENCY A(1)(TO) PHONON IN PBTIO3 SO PHYSICAL REVIEW B LA English DT Article ID ZONE-CENTER PHONONS; SINGLE-CRYSTALS; TETRAGONAL BATIO3; LEAD TITANATE; SPECTROSCOPY; PRESSURE; MODES AB Detailed Raman studies of the optical phonons in high-quality single-crystal PbTiO3 indicate that the mode energies and symmetry assignments in the literature [G. Bums and B. Scott, Phys. Rev. B 7, 3088 (1973)] must be revised. In this study, all k congruent-to 0 optical-phonon modes are directly observed and are shown to obey rigorously the Raman selection rules. The angular dependence of the phonon frequencies indicates that the energy of the lowest-frequency A1(TO) mode is higher than the energy of the lowest-frequency E(LO) mode at 300 K. This indicates that these two k congruent-to 0 modes will cross at elevated temperature. The A1(TO) mode exhibits an anomalous line shape, which we attribute to the anharmonic nature of the lattice. The phonon frequencies determine the clamped dielectric constants, epsilon(a)(0) and epsilon(c)(0), using the Lydanne-Sachs-Teller relation. These values, when compared to those obtained from impedance measurements, indicate no dielectric dispersion in PbTiO3 between the MHz region and the Raman region. RP FOSTER, CM (reprint author), ARGONNE NATL LAB,DIV MATH SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 37 TC 162 Z9 163 U1 2 U2 14 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 OCT 1 PY 1993 VL 48 IS 14 BP 10160 EP 10167 DI 10.1103/PhysRevB.48.10160 PG 8 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800023 ER PT J AU STERNLIEB, BJ SHIRANE, G WERNER, SA FAWCETT, E AF STERNLIEB, BJ SHIRANE, G WERNER, SA FAWCETT, E TI FINCHER-BURKE EXCITATIONS IN THE TRANSVERSE SPIN-DENSITY-WAVE PHASE OF CHROMIUM SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC EXCITATIONS AB High-resolution neutron-scattering measurements of the transversely polarized spin-density-wave phase of single-domain chromium are reported. The well-defined excitations observed by Fincher, Shirane, and Werner and later attributed to propagating modes by Burke et al. are characterized at energy transfers 0.75 less-than-or-equal-to DELTAE less-than-or-equal-to 4 meV. These modes appear between the unresolved spin-wave peaks at Q+/-=a*(1+/-delta,0,0) and follow a linear dispersion that originates at Q+/-. In contrast to previous measurements, no evidence of symmetric excitations at \q\ < \Q-\ or \q\ > \Q+\ is seen at any energy transfer. The absence of symmetric branches argues against a magnetovibrational interpretation of these modes. The susceptibility associated with these Fincher-Burke excitations is found to vary roughly as the inverse of the energy, 1 /omega(FB). C1 UNIV MISSOURI,DEPT PHYS,COLUMBIA,MO 65211. UNIV TORONTO,DEPT PHYS,TORONTO M5S 1A7,ONTARIO,CANADA. RP STERNLIEB, BJ (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 9 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 14 BP 10217 EP 10220 DI 10.1103/PhysRevB.48.10217 PG 4 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800029 ER PT J AU BOETTGER, JC AF BOETTGER, JC TI THEORETICAL STRAIN-DEPENDENT PROPERTIES OF SQUARE AND HEXAGONAL FE MONOLAYERS SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-PROPERTIES; METALLIC MONOLAYERS; SPIN ANISOTROPY; OVERLAYERS; FILMS; ELEMENTS; LITHIUM AB The total energy, work function, and spin magnetic moment of Fe monolayers with square and hexagonal symmetries have been calculated as functions of strain via all-electron full-potential local-spin-density-approximation electronic-structure calculations with the linear combination of Gaussian-type orbitals fitting-function technique. The ferromagnetic Fe monolayer with hexagonal symmetry is predicted to have a substantially lower energy than the paramagnetic hexagonal monolayer or square monolayers with either spin state. The latter three monolayers are nearly degenerate with their energies spanning a total range of about 0.02 eV. The equilibrium nearest-neighbor distances of the four monolayers are compressed relative to the theoretical bulk value. The work functions of the ferromagnetic monolayers are predicted to be highly strain dependent and are in reasonable agreement with the experimental work function for the (001) surface of bcc Fe. The spin magnetic moment vs strain curves for the two spatial symmetries differ significantly near the ferromagnetic --> paramagnetic phase transition. RP BOETTGER, JC (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 30 TC 5 Z9 5 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 14 BP 10247 EP 10253 DI 10.1103/PhysRevB.48.10247 PG 7 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800033 ER PT J AU KANG, JS YANG, CJ LEE, YP OLSON, CG CHO, EJ OH, SJ ANDERSON, RO LIU, LZ PARK, JH ALLEN, JW ELLIS, WP AF KANG, JS YANG, CJ LEE, YP OLSON, CG CHO, EJ OH, SJ ANDERSON, RO LIU, LZ PARK, JH ALLEN, JW ELLIS, WP TI PHOTOEMISSION-STUDY OF SMCO2 SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-PHOTOEMISSION; CORE-LEVEL SPECTRA; VALENCE-BAND SATELLITE; SURFACE MIXED-VALENCE; RARE-EARTH-METALS; ELECTRONIC-STRUCTURE; INCOMPLETE SHELL; PHOTOELECTRON-SPECTRA; RESONANT-PHOTOEMISSION; 2-ELECTRON RESONANCES AB The electronic structure Of SmCo2 is investigated with photoemission spectroscopy (PES). All the PES spectra are consistent in showing that the bulk Sm ions are trivalent, but that the surface has divalent Sm ions and is probably inhomogeneously mixed valent. Both the Sm 4f valence band and Sm 3d core level PES spectra are found to be substantially broader than those of Sm metal. The observed larger linewidths for SmCo2, as compared to those of pure Sm metal, suggest a larger lifetime broadening, probably due to an increased number of valence-band electrons, and a larger 4f hybridization, mainly to Co 3d states. Weak satellite structures are observed in the Co 3d valence band and Co 2p core level PES spectra, indicating Co 3d correlation effects. The comparison of the experimental valence-band PES spectrum with the theoretical Co 3d projected local density of states also suggests that Co 3d correlation effects in SmCo2 are non-negligible. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. SEOUL NATL UNIV,DEPT PHYS,SEOUL 151742,SOUTH KOREA. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109. RP KANG, JS (reprint author), RES INST IND SCI & TECHNOL,POHANG 790600,SOUTH KOREA. NR 72 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1993 VL 48 IS 14 BP 10327 EP 10334 DI 10.1103/PhysRevB.48.10327 PG 8 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800043 ER PT J AU BERAN, P LAUGHLIN, RB AF BERAN, P LAUGHLIN, RB TI FRACTIONAL-STATISTICS GAS WITH SPIN AND STABILITY OF THE SUPERFLUID STATE SO PHYSICAL REVIEW B LA English DT Article ID DIMENSIONAL ELECTRON-GAS; GROUND-STATE; QUANTUM-MECHANICS; APPROXIMATION; EXCITATIONS; LA2CUO4; LIQUID AB The fractional-statistics gas with a spin degree of freedom is investigated using the random-phase-approximation procedure of Dai et al. [Phys. Rev. B 46, 5642 (1992)]. The results are used to evaluate the stability of the superfluid state of the dilute holon system in the context of the commensurate flux phase. Spin-wave instabilities induced by gauge interactions are found to occur at extremely low density, implying that superfluidity of the fractional-statistics gas is correct in the presence of a spin degree of freedom. Spin-wave and density-wave collective excitations are also studied in presence of Coulomb repulsion between holons. The resulting instabilities at small density are estimated to occur in a density range of 0.01-0.1 holons per lattice site. C1 STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. RP BERAN, P (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 27 TC 4 Z9 4 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 OCT 1 PY 1993 VL 48 IS 14 BP 10382 EP 10390 DI 10.1103/PhysRevB.48.10382 PG 9 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800047 ER PT J AU MCELFRESH, M MAPLE, MB WILLIS, JO SCHIFERL, D SMITH, JL FISK, Z COX, DL AF MCELFRESH, M MAPLE, MB WILLIS, JO SCHIFERL, D SMITH, JL FISK, Z COX, DL TI PRESSURE-DEPENDENCE OF THE STATIC MAGNETIC-SUSCEPTIBILITY OF THE HEAVY-FERMION SUPERCONDUCTOR UBE13 SO PHYSICAL REVIEW B LA English DT Article ID SYSTEMS; BEHAVIOR; FIELD; MODEL AB The pressure dependence of the static magnetic susceptibility chi(T) of the heavy-electron superconductor UBe13 was investigated over temperatures ranging from 1.5 to 300 K and at pressures from 1 bar to 8 kbar. It is linear in pressure over the full temperature range, having a small constant pressure dependence at higher temperatures that increases rapidly below about T= 150 K. The maximal value of the relative susceptibility change [1/chi(d(chi)/dP) ] is about 1% per kbar. The Curie-Weiss law is obeyed in the temperature range 100 to 300 K with the effective magnetic moment p(eff)=3.46mu(B) independent of pressure, while the paramagnetic Curie temperature THETA approximately -100 K becomes more negative with pressure. The lattice parameter of cubic UBe13 was measured as a function of pressure, permitting a determination of a compressibility value of -9.2 X 10(-4) kbar-1 near ambient pressure. The pressure dependence of chi(T) is significantly weaker than that of the specific-heat coefficient C(T)/T, we discuss whether this can be resolved by (i) consideration of intersite antiferromagnetic interactions, or (ii) the quadrupolar Kondo-effect model, and conclude that the latter provides a stronger explanation of the results. C1 UNIV CALIF SAN DIEGO,INST PURE & APPL PHYS SCI,LA JOLLA,CA 92093. UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. NR 46 TC 19 Z9 19 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 OCT 1 PY 1993 VL 48 IS 14 BP 10395 EP 10403 DI 10.1103/PhysRevB.48.10395 PG 9 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800049 ER PT J AU XU, M FINNEMORE, DK CRABTREE, GW VINOKUR, VM DABROWSKI, B HINKS, DG ZHANG, K AF XU, M FINNEMORE, DK CRABTREE, GW VINOKUR, VM DABROWSKI, B HINKS, DG ZHANG, K TI SURFACE BARRIERS AND BULK PINNING IN YBA2CU4O8 SO PHYSICAL REVIEW B LA English DT Note ID HIGH-TC SUPERCONDUCTORS; FLUX; CRYSTALS; YBA2CU3O7-DELTA; MAGNETIZATION; PENETRATION; RELAXATION; CROSSOVER; FIELD AB Strong surface barrier effects have been observed for the motion of vortices in single crystal YBa2Cu4O8. They are most easily visible between 25 and 50 K where a typical hysteresis loop for fields less than 1 tesla shows a classic Bean-Livingston shape with magnetization close to zero for the leg of the hysteresis loop where vortices are exiting the sample. At higher fields, bulk pinning grows dramatically with a magnetic hysteresis loop that rises and falls with a classic fishtail shape. For these YBa2Cu4O8 single crystals, surface barriers dominate at low field with little bulk pinning. At 35 K, bulk pinning turns on at about 1 T. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. RP XU, M (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 19 TC 58 Z9 58 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 OCT 1 PY 1993 VL 48 IS 14 BP 10630 EP 10633 DI 10.1103/PhysRevB.48.10630 PG 4 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800089 ER PT J AU LIU, SH KLEMM, RA AF LIU, SH KLEMM, RA TI ENERGY-GAP STRUCTURE OF LAYERED SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Note ID COPPER-OXIDE SUPERCONDUCTORS; ANISOTROPY; INTRALAYER; TC AB We have analyzed the energy gaps and density of states (DOS) of layered superconductors with two inequivalent layers in a unit cell in the c-axis direction. In the physically interesting parameter range where the interlayer hopping strengths of the quasiparticles are comparable to the critical temperature, the DOS curves have a double-peak structure, where the extra peaks are manifestations of interband pairing. Unlike BCS superconductors, the peaks are logarithmic singularities. Our simulated tunneling characteristics bear close resemblance to experimental results. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP LIU, SH (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 12 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 OCT 1 PY 1993 VL 48 IS 14 BP 10650 EP 10652 DI 10.1103/PhysRevB.48.10650 PG 3 WC Physics, Condensed Matter SC Physics GA MB648 UT WOS:A1993MB64800094 ER PT J AU MANTICA, PF ROBERTSON, JD BAUM, EM WALTERS, WB AF MANTICA, PF ROBERTSON, JD BAUM, EM WALTERS, WB TI LEVEL STRUCTURE OF THE ODD-MASS PR ISOTOPES .3. LEVELS OF PR-147(88) POPULATED IN THE BETA-DECAY OF 56-S CE-147 SO PHYSICAL REVIEW C LA English DT Article ID PROTON-HOLE STATES; NUCLEI; REGION; MOMENTS; BA-145; BANDS; MODEL AB The structure of 147Pr has been investigated by performing measurements of gamma-ray and conversion-electron singles and gammagamma coincidence spectra of mass separated sources of 56-s 147Ce. The proposed level scheme extends the known structure of 147Pr to an energy of 2.2 MeV and includes several levels below 1.2 MeV that have not been identified in previous decay studies of 147Ce. Measurement of the conversion coefficients for several transitions has led to the assignment of negative parity to the levels at 362, 452, 467, and 608 keV in 147Pr, which show properties similar to low-energy negative-parity states identified in Pr-145(86), La-145(88), and Pm-149(88). The presence of low-energy negative-parity states suggests that configurations having significantly different deformation, related to the highly deformed region above N = 90 and/or to the reflection asymmetric region identified around 145Ba, may manifest themselves at low energy in these nuclides. C1 OAK RIDGE INST SCI & EDUC,UNISOR,OAK RIDGE,TN 37831. RP MANTICA, PF (reprint author), UNIV MARYLAND,DEPT CHEM & BIOCHEM,COLL PK,MD 20742, USA. NR 40 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1579 EP 1593 DI 10.1103/PhysRevC.48.1579 PG 15 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800012 ER PT J AU FRANKLE, CM BOWMAN, JD CRAWFORD, BE DELHEIJ, PPJ GOULD, CR HAASE, DG KNUDSON, JN MITCHELL, GE PATTERSON, SS PENTTILA, SI POPOV, YP ROBERSON, NR SEESTROM, SJ SHARAPOV, EI YEN, YF YOO, SH YUAN, VW ZHU, X AF FRANKLE, CM BOWMAN, JD CRAWFORD, BE DELHEIJ, PPJ GOULD, CR HAASE, DG KNUDSON, JN MITCHELL, GE PATTERSON, SS PENTTILA, SI POPOV, YP ROBERSON, NR SEESTROM, SJ SHARAPOV, EI YEN, YF YOO, SH YUAN, VW ZHU, X TI NEUTRON RESONANCE SPECTROSCOPY OF IN-113 AND IN-115 SO PHYSICAL REVIEW C LA English DT Article ID PARITY NONCONSERVATION; FLUCTUATIONS; PHYSICS; SPECTRA; TH-232; U-238 AB The neutron total cross section for natural indium was measured for E(n) = 25-500 eV with the time-of-flight method at the Los Alamos Neutron Scattering Center. The neutron capture reaction was studied on a highly enriched sample (99.99%) of In-115. A total of 47 previously unreported resonances were observed. The combination of the two measurements allowed assignment of the new resonances to In-113 or In-115. Resonance parameters were extracted for all of the neutron resonances observed. C1 DUKE UNIV,DURHAM,NC 27708. TRIANGLE UNIV,NUCL LAB,DURHAM,NC 27708. TRIUMF,VANCOUVER V6T 2A3,BC,CANADA. DUBNA JOINT INST NUCL RES,DUBNA 141980,RUSSIA. N CAROLINA STATE UNIV,RALEIGH,NC 27695. RP FRANKLE, CM (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Gould, Christopher/M-7676-2013 NR 27 TC 5 Z9 5 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 OCT PY 1993 VL 48 IS 4 BP 1601 EP 1608 DI 10.1103/PhysRevC.48.1601 PG 8 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800014 ER PT J AU AUFDERHEIDE, MB BLOOM, SD RESLER, DA MATHEWS, GJ AF AUFDERHEIDE, MB BLOOM, SD RESLER, DA MATHEWS, GJ TI SHELL-MODEL CALCULATIONS OF GAMOW-TELLER STRENGTH IN V-51, FE-54, CO-59 SO PHYSICAL REVIEW C LA English DT Article ID WEAK-INTERACTION RATES; CHARGE-EXCHANGE REACTIONS; INTERMEDIATE-MASS NUCLEI; SUM-RULE; STELLAR AB The Gamow-Teller (GT) strength functions of V-51, Fe-54, and Co-59 measured by recent charge-exchange experiments have been studied using shell-model calculations employing two model spaces. The shell model is fairly successful at reproducing GT strength in the (p,n) direction, but the agreement is not as good in the (n,p) direction. It is found that both directions can be fit consistently by shifting single particle energies in a systematic manner. It is found that roughly 75% of the sum-rule strength can be seen in the experiments for both V-51 and Fe-54. It is also found that roughly 35% of the GT strength predicted by the shell model is seen in the (n,p) direction for all three nuclei, but that the quenching in the (p,n) direction varies with nucleus. The consequences of these findings for improving the calculation of weak interaction rates are discussed. RP AUFDERHEIDE, MB (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 24 TC 38 Z9 38 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1677 EP 1685 DI 10.1103/PhysRevC.48.1677 PG 9 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800023 ER PT J AU MAGIERSKI, P CWIOK, S DOBACZEWSKI, J NAZAREWICZ, W AF MAGIERSKI, P CWIOK, S DOBACZEWSKI, J NAZAREWICZ, W TI APPROXIMATE PARTICLE NUMBER PROJECTION FOR ROTATING NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID PAIRING CORRELATIONS; MODEL; EQUATIONS; FIELD AB Pairing correlations in rotating nuclei are discussed within the Lipkin-Nogami method. The accuracy of the method is tested for the Krumlinde-Szymanski R(5) model. The results of calculations are compared with those obtained from the standard mean field theory and particle-number projection method, and with exact solutions. C1 UNIV WARSAW,INST THEORET PHYS,PL-00681 WARSAW,POLAND. OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,DIV PHYS,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. RP MAGIERSKI, P (reprint author), WARSAW UNIV TECHNOL,INST PHYS,UL KOSZYKOWA 75,PL-00662 WARSAW,POLAND. NR 28 TC 38 Z9 38 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1686 EP 1694 DI 10.1103/PhysRevC.48.1686 PG 9 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800024 ER PT J AU GUIDRY, MW STRAYER, MR WU, CL FENG, DH AF GUIDRY, MW STRAYER, MR WU, CL FENG, DH TI SOME GENERAL CONSTRAINTS ON IDENTICAL BAND SYMMETRIES SO PHYSICAL REVIEW C LA English DT Article ID FERMION DYNAMICAL SYMMETRY; SUPERDEFORMED BANDS; NUCLEI; MODEL; SHAPES; GD-149; STATES AB We argue on general grounds that nearly identical bands observed for superdeformation and less frequently for normal deformation must be explicable in terms of a symmetry having a microscopic basis. We assume that the unknown symmetry is associated with a Lie algebra generated by terms bilinear in fermion creation and annihilation operators. Observed features of these bands and the general properties of Lie groups are then used to place constraints on acceptable algebras. Additional constraints are placed by assuming that the collective spectrum is associated with a dynamical symmetry, and examining the subgroup structure required by phenomenology. We observe that requisite symmetry cannot be unitary, and that the simplest known group structures consistent with these minimal criteria are associated with the Ginocchio algebras employed in the fermion dynamical symmetry model. However, our arguments are general in nature, and we propose that they imply model-independent constraints on any candidate explanation for identical bands. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. DREXEL UNIV,DEPT PHYS & ATMOSPHER SCI,PHILADELPHIA,PA 19104. RP GUIDRY, MW (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 28 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1739 EP 1744 DI 10.1103/PhysRevC.48.1739 PG 6 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800030 ER PT J AU ZAMFIR, NV COTTLE, PD JOHNSON, JL CASTEN, RF AF ZAMFIR, NV COTTLE, PD JOHNSON, JL CASTEN, RF TI OCTUPOLE FRAGMENTATION AND O(6) SYMMETRY IN EVEN-A PT ISOTOPES SO PHYSICAL REVIEW C LA English DT Article ID INTERACTING BOSON MODEL; INELASTIC PROTON-SCATTERING; COLLECTIVE NUCLEAR STATES; TRANSITION-PROBABILITIES; REGION; SPECTROSCOPY; EXCITATIONS AB The systematic behavior of the fragmentation of the low energy octupole state over a wide range of mass regions is well reproduced using a U(5)-->SU(3) transition in the context of the interacting boson approximation. However, the octupole fragmentation in the even-A Pt isotopes deviates strongly from both the systematic behavior of other nuclei and the U(5)-->SU(3) calculations. This anomalous behavior can be explained in terms of the O(6) nature of the stable Pt isotopes. It is concluded that anomalously large fragmentation of the low energy octupole state is a signature of nuclei conforming to the O(6) dynamical symmetry. C1 CLARK UNIV,WORCESTER,MA 01610. INST ATOM PHYS,BUCHAREST,ROMANIA. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. RP ZAMFIR, NV (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Zamfir, Nicolae Victor/F-2544-2011 NR 42 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1745 EP 1751 DI 10.1103/PhysRevC.48.1745 PG 7 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800031 ER PT J AU WISE, JE BRAUNSTEIN, MR HOIBRATEN, S KOHLER, MD KRISS, BJ OUYANG, J PETERSON, RJ MCGILL, JA MORRIS, CL SEESTROM, SJ WHITTON, RM ZUMBRO, JD EDWARDS, CM WILLIAMS, AL AF WISE, JE BRAUNSTEIN, MR HOIBRATEN, S KOHLER, MD KRISS, BJ OUYANG, J PETERSON, RJ MCGILL, JA MORRIS, CL SEESTROM, SJ WHITTON, RM ZUMBRO, JD EDWARDS, CM WILLIAMS, AL TI QUASI-FREE PION-SCATTERING AT 500 MEV SO PHYSICAL REVIEW C LA English DT Article ID INELASTIC ELECTRON-SCATTERING; INTERMEDIATE ENERGIES; NUCLEUS SCATTERING; ELASTIC PEAK; REGION; MODEL AB Non-charge-exchange inclusive cross sections have been measured at 500 MeV incident pion energy at quasifree scattering kinematics for both positive and negative pion charges. Peaks identified with quasifree knockout are seen at momentum transfers from 314 to 724 MeV/c. The widths and sizes of the peaks seen are consistent with the knockout of single nucleons from the nuclear surface. The data are consistent with no softening of the pion quasifree response at high momentum transfer, in contrast to the result seen in 500-MeV pion charge exchange data. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. UNIV TEXAS,AUSTIN,TX 78712. RP WISE, JE (reprint author), UNIV COLORADO,NUCL PHYS LAB,BOULDER,CO 80309, USA. NR 44 TC 14 Z9 14 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 OCT PY 1993 VL 48 IS 4 BP 1840 EP 1848 DI 10.1103/PhysRevC.48.1840 PG 9 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800040 ER PT J AU FREEDMAN, SJ GEESAMAN, DF GILMAN, R GREEN, MC HOLT, RJ JACKSON, HE KINNEY, ER KOWALCZYK, R MARCHAND, C NAPOLITANO, J NELSON, J POTTERVELD, DH ZEIDMAN, B SEGEL, RE TUNG, TY BECK, D BOYD, G COLLINS, D FILIPPONE, BW JONES, CE JOURDAN, J MCKEOWN, RD MILNER, R WALKER, R BOSTED, PE MEZIANI, ZE MINEHART, R AF FREEDMAN, SJ GEESAMAN, DF GILMAN, R GREEN, MC HOLT, RJ JACKSON, HE KINNEY, ER KOWALCZYK, R MARCHAND, C NAPOLITANO, J NELSON, J POTTERVELD, DH ZEIDMAN, B SEGEL, RE TUNG, TY BECK, D BOYD, G COLLINS, D FILIPPONE, BW JONES, CE JOURDAN, J MCKEOWN, RD MILNER, R WALKER, R BOSTED, PE MEZIANI, ZE MINEHART, R TI 2-BODY DISINTEGRATION OF THE DEUTERON WITH 0.8-1.8-GEV PHOTONS SO PHYSICAL REVIEW C LA English DT Article ID FORM-FACTORS; SCATTERING; PHOTODISINTEGRATION; AMPLITUDES; MOMENTUM; HADRONS; MODEL AB The differential cross section for the reaction H-2(gamma,p)n has been measured at several center-of-mass angles ranging from 50-degrees to 143-degrees for photon energies between 0.8 and 1.8 GeV. The experiment was performed at the SLAC-NPAS facility with the use of the 1.6 GeV/c spectrometer to detect the high energy protons produced by a bremsstrahlung beam directed at a liquid deuterium target. Contributions from concurrent disintegration by the residual electron beam were determined by measuring the proton yield without the Cu photon radiator. At angles not very far from 90-degrees, the energy dependence of the cross sections is consistent with predictions of scaling using counting rules for consitituent quarks. At least one theoretical calculation based on a meson-baryon picture of the reaction is able to reproduce the magnitude and energy dependence of the 90-degrees cross section. The angular distribution exhibits a large enhancement at backward angles at the higher energies. C1 NORTHWESTERN UNIV,EVANSTON,IL 60201. CALTECH,PASADENA,CA 91125. AMERICAN UNIV,WASHINGTON,DC 20016. STANFORD UNIV,STANFORD,CA 94305. UNIV VIRGINIA,CHARLOTTESVILLE,VA 22903. UNIV CALIF BERKELEY,BERKELEY,CA 94720. RUTGERS UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08855. LECROY RES SYST,SPRING VALLEY,NY 10977. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. CENS,F-91191 GIF SUR YVETTE,FRANCE. RENSSELAER POLYTECH INST,DEPT PHYS,TROY,NY 12180. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. UNIV BASEL,DEPT PHYS,CH-4056 BASEL,SWITZERLAND. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP FREEDMAN, SJ (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. RI Holt, Roy/E-5803-2011 NR 35 TC 55 Z9 55 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 OCT PY 1993 VL 48 IS 4 BP 1864 EP 1878 DI 10.1103/PhysRevC.48.1864 PG 15 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800042 ER PT J AU HELMER, KG WU, CY CLINE, D KAVKA, AE KERNAN, WJ VOGT, EG GUIDRY, MW HAN, XL KINCAID, RW LIU, XT SCHECTER, H RASMUSSEN, JO SHIHABELDIN, A STOYER, MA HALBERT, ML AF HELMER, KG WU, CY CLINE, D KAVKA, AE KERNAN, WJ VOGT, EG GUIDRY, MW HAN, XL KINCAID, RW LIU, XT SCHECTER, H RASMUSSEN, JO SHIHABELDIN, A STOYER, MA HALBERT, ML TI SEARCH FOR DIABOLICAL PAIR TRANSFER IN 2-NEUTRON TRANSFER-REACTIONS SO PHYSICAL REVIEW C LA English DT Article ID ROTATING NUCLEI; COULOMB-EXCITATION; REGION; PHASE AB The effects of proximity to a diabolic point on neutron transfer in nuclear physics is explored using the reactions Pb-206 (Gd-156,Gd-154)Pb-208 (presumed diabolic case) and Pb-206 (Gd-156,Gd-158)Pb-204 (nondiabolic case) at a laboratory bombarding energy of 888 MeV. Deexcitation gamma rays were measured using a particle-particle-gamma triple-coincidence method. A comparison of the spin distributions from each of the above reactions was used to search for a suppression of the gamma-ray yields that has been predicted within the cranked Hartree-Fock-Bogoliubov model for diabolical pair transfer. The latest calculations agree with the results of this experiment. The influence of diabolical pair transfer is more subtle than expected for the case of sharp backbending nuclei such as Gd-154. No clear evidence for diabolical pair transfer was observed within the sensitivity range of this experiment, nor was it possible to unambiguously place the diabolical point between Gd-154 and Gd-156. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37966. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP HELMER, KG (reprint author), UNIV ROCHESTER,NUCL STRUCT RES LAB,ROCHESTER,NY 14627, USA. NR 14 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1879 EP 1883 DI 10.1103/PhysRevC.48.1879 PG 5 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800043 ER PT J AU GARVEY, G KOLBE, E LANGANKE, K KREWALD, S AF GARVEY, G KOLBE, E LANGANKE, K KREWALD, S TI ROLE OF STRANGE QUARKS IN QUASI-ELASTIC NEUTRINO SCATTERING SO PHYSICAL REVIEW C LA English DT Article ID OPPOSITE-SIGN DIMUONS; ELASTIC-SCATTERING; PROTON; SPIN; NUCLEON; TERM AB Confirming our previous proposal, we show within a continuum random-phase approximation calculation that the ratio of proton-to-neutron neutrino-induced quasielastic yield is a sensitive way to determine the strange quark axial form factor of the nucleon. Particularly, we find that the ratio is virtually independent of final state interactions (accounted for by a finite-range force derived from the Bonn meson-exchange potential) and nuclear structure effects. We present the ratio calculated for the neutrino beam available in an experiment currently approved at LAMPF. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. FA JULICH,INST KERNPHYS,W-5170 JULICH,GERMANY. RP GARVEY, G (reprint author), CALTECH,W K KELLOGG RADIAT LAB,106-38,PASADENA,CA 91125, USA. OI Krewald, Siegfried/0000-0002-8596-8429 NR 24 TC 65 Z9 65 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 OCT PY 1993 VL 48 IS 4 BP 1919 EP 1925 DI 10.1103/PhysRevC.48.1919 PG 7 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800049 ER PT J AU SIEGEL, PB GIBBS, WR AF SIEGEL, PB GIBBS, WR TI PION-SCATTERING FROM SPIN 1/2 NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID CHARGE-EXCHANGE; ELASTIC-SCATTERING; POLARIZED C-13; ASYMMETRY; RESONANCE; REGION AB Left-right asymmetries for pion elastic scattering and charge exchange from polarized C-13 and N-15 are calculated and compared with the available data. It is shown for elastic scattering that the quadrupole spin-flip contribution is dominant in the determination of the asymmetry at forward angles. The distorted wave impulse approximation and optical model treatments are compared and a qualitative discussion of the underlying physics of the sign of the asymmetry in the first diffraction minimum is presented. C1 NEW MEXICO STATE UNIV,LAS CRUCES,NM 88003. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP SIEGEL, PB (reprint author), CALIF STATE POLYTECH UNIV POMONA,POMONA,CA 91768, USA. NR 11 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1939 EP 1947 DI 10.1103/PhysRevC.48.1939 PG 9 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800051 ER PT J AU SARAFIAN, H JOHNSON, MB SICILIANO, ER AF SARAFIAN, H JOHNSON, MB SICILIANO, ER TI MEDIUM MODIFICATION OF MESON PROPAGATION BETWEEN 2 NUCLEONS IN FINITE NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID DOUBLE-CHARGE-EXCHANGE; LOW-ENERGY PIONS; SCATTERING AB We derive simple expressions for the effect of medium modifications (or distortions) on the propagation of a pion between two nucleons in a nucleus. Our results are applicable to pion reactions in a variety of situations, but we are particularly interested in the influence of distortions on pion double charge exchange at low energy. We are able to calculate these distortions for a finite nucleus using a realistic choice of optical potential. We represent their effect as a modification of the S- and P-wave pion-nucleon scattering amplitudes that occur at the location of the first (or last) nucleon to be struck. We illustrate our method by showing numerical results for a shematic optical potential. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP SARAFIAN, H (reprint author), PENN STATE UNIV,DEPT PHYS,YORK,PA 17403, USA. NR 23 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP 1988 EP 1998 DI 10.1103/PhysRevC.48.1988 PG 11 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800055 ER PT J AU CUMMING, JB CHU, YY HAUSTEIN, PE AF CUMMING, JB CHU, YY HAUSTEIN, PE TI INTERACTIONS OF 13.6-GEV NUCLEON O-16 AND SI-28 WITH CARBON, ALUMINUM, AND COPPER SO PHYSICAL REVIEW C LA English DT Note ID RELATIVISTIC HEAVY-IONS; GEV C-12 IONS; CROSS-SECTIONS; TARGET FRAGMENTATION; MOMENTUM-TRANSFER; RECOIL PROPERTIES; COMPLEX NUCLEI; HIGH-ENERGIES; PROTONS; SILVER AB Cross sections for forming Na-24 and F-18 by the interactions of 13.6-GeV/nucleon O-16 and Si-28 ions with Al and for forming Na-24 in O-16 interactions with Cu have been measured relative to the cross section for forming C-11 from carbon. The results are generally consistent with energy-independent inclusive cross sections (limiting fragmentation) for heavy ions between approximately 2 and 13.6 GeV/nucleon. However, comparison of the heavy-ion data with those for high-energy protons indicates a significantly weaker dependence on projectile size than that predicted by the factorization hypothesis for sigma(C)(C-11), sigma(Al)(F-18), and sigma(Al)(Na-24). The dependence is slightly stronger in the case of sigma(Cu)(Na-24). RP CUMMING, JB (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Cumming, James/I-3358-2013 OI Cumming, James/0000-0001-6930-0958 NR 24 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 OCT PY 1993 VL 48 IS 4 BP 2068 EP 2071 DI 10.1103/PhysRevC.48.2068 PG 4 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800062 ER PT J AU FENG, DH GUIDRY, MW PAN, XW WU, CL ZLATEV, I AF FENG, DH GUIDRY, MW PAN, XW WU, CL ZLATEV, I TI EFFECTIVE FERMION SO(6) DYNAMICAL SYMMETRY IN THE PLATINUM NUCLEI SO PHYSICAL REVIEW C LA English DT Note ID INTERACTING BOSON MODEL; O(6) LIMIT; MONOPOLE AB It is shown that a very accurate fermion SO(6) dynamical symmetry exists for Pt-196, even though the coupled system has no such formal dynamical symmetry in the fermion dynamical symmetry model. Implications of this effective dynamical symmetry are discussed. C1 CHUNG YUAN CHRISTIAN UNIV,DEPT PHYS,CHUNGLI 32023,TAIWAN. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. BEREA COLL,DEPT PHYS,BEREA,KY 40404. RP FENG, DH (reprint author), DREXEL UNIV,DEPT PHYS,PHILADELPHIA,PA 19104, USA. NR 21 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1993 VL 48 IS 4 BP R1488 EP R1491 PG 4 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800003 ER PT J AU ZAHAR, M BELBOT, M KOLATA, JJ LAMKIN, K THOMPSON, R ORR, NA KELLEY, JH KRYGER, RA MORRISSEY, DJ SHERRILL, BM WINGER, JA WINFIELD, JS AF ZAHAR, M BELBOT, M KOLATA, JJ LAMKIN, K THOMPSON, R ORR, NA KELLEY, JH KRYGER, RA MORRISSEY, DJ SHERRILL, BM WINGER, JA WINFIELD, JS TI MOMENTUM DISTRIBUTIONS FOR BE-12, BE-14 FRAGMENTATION SO PHYSICAL REVIEW C LA English DT Note ID INTERACTION CROSS-SECTIONS; NUCLEAR RADII; LI-11 AB Data on the fragmentation of Be-12, Be-14, on C-12 at 56 and 65 MeV per nucleon have been obtained. The Be-12 fragments from the breakup of Be-14 display both a narrow longitudinal momentum distribution and a distinctive angular distribution that is consistent with an extended neutron ''halo'' in this nucleus. This is the first experiment in which both longitudinal and transverse fragment momentum, of exotic nuclei have been simultaneously measured. C1 MICHIGAN STATE UNIV,NATL SUPERCOND CYCLOTRON LAB,E LANSING,MI 48824. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. RP ZAHAR, M (reprint author), UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556, USA. RI Sherrill, Bradley/B-4098-2009; Sherrill, Bradley/B-3378-2011 NR 16 TC 52 Z9 52 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 OCT PY 1993 VL 48 IS 4 BP R1484 EP R1487 PG 4 WC Physics, Nuclear SC Physics GA MC118 UT WOS:A1993MC11800002 ER PT J AU ABE, F ALBROW, M AMIDEI, D ANWAYWIESE, C APOLLINARI, G ATAC, M AUCHINCLOSS, P AZZI, P BADEN, AR BACCHETTA, N BADGETT, W BAILEY, MW BAMBERGER, A DEBARBARO, P BARBAROGALTIERI, A BARNES, VE BARNETT, BA BAUER, G BAUMANN, T BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENJAMIN, D BENLLOCH, J BENSINGER, J BERETVAS, A BERGE, JP BERTOLUCCI, S BIERY, K BHADRA, S BINKLEY, M BISELLO, D BLAIR, R BLOCKER, C BODEK, A BOLOGNESI, V BOOTH, AW BOSWELL, C BRANDENBURG, G BROWN, D BUCKLEYGEER, E BUDD, HS BUSETTO, G BYONWAGNER, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CANER, A CAREY, R CARITHERS, W CARLSMITH, D CARROLL, JT CASHMORE, R CASTRO, A CERVELLI, F CHADWICK, K CHAPMAN, J CHIARELLI, G CHINOWSKY, W CIHANGIR, S CLARK, AG COBAL, M CONNOR, D CONTRERAS, M COOPER, J CORDELLI, M CRANE, D CUNNINGHAM, JD DAY, C DEJONGH, F DELLAGNELLO, S DELLORSO, M DEMORTIER, L DENBY, B DERWENT, PF DEVLIN, T DIBITONTO, D DICKSON, M DRUCKER, RB EINSWEILER, K ELIAS, JE ELY, R ENO, S ERREDE, S ETCHEGOYEN, A FARHAT, B FELDMAN, GJ FLAUGHER, B FOSTER, GW FRANKLIN, M FREEMAN, J FRISCH, H FUESS, T FUKUI, Y GARFINKEL, AF GAUTHIER, A GEER, S GERDES, DW GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GOLD, M GONZALEZ, J GOULIANOS, K GRASSMANN, H GRIECO, GM GRINDLEY, R GROSSOPILCHER, C HABER, C HAHN, SR HANDLER, R HARA, K HARRAL, B HARRIS, RM HAUGER, SA HAUSER, J HAWK, C HESSING, T HOLLEBEEK, R HOLLOWAY, L HONG, S HOUK, G HU, P HUBBARD, B HUFFMAN, BT HUGHES, R HURST, P HUTH, J HYLEN, J INCAGLI, M INO, T ISO, H JENSEN, H JESSOP, CP JOHNSON, RP JOSHI, U KADEL, RW KAMON, T KANDA, S KARDELIS, DA KARLINER, I KEARNS, E KEEBLE, L KEPHART, R KESTEN, P KEUP, RM KEUTELIAN, H KIM, D KIM, SB KIM, SH KIM, YK KIRSCH, L KONDO, K KONIGSBERG, J KORDAS, K KOVACS, E KRASBERG, M KUHLMANN, SE KUNS, E LAASANEN, AT LAMMEL, S LAMOUREUX, JI LEONE, S LEWIS, JD LI, W LIMON, P LINDGREN, M LISS, TM LOCKYER, N LORETI, M LOW, EH LUCCHESI, D LUCHINI, CB LUKENS, P MAAS, P MAESHIMA, K MANGANO, M MARRINER, JP MARIOTTI, M MARKELOFF, R MARKOSKY, LA MATTINGLY, R MCINTYRE, P MENZIONE, A MESCHI, E MEYER, T MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MIYASHITA, S MORITA, Y MOULDING, S MUELLER, J MUKHERJEE, A MULLER, T NAKAE, LF NAKANO, I NELSON, C NEUBERGER, D NEWMANHOLMES, C NG, JST NINOMIYA, M NODULMAN, L OGAWA, S PAOLETTI, R PAPADIMITRIOU, V PARA, A PARE, E PARK, S PATRICK, J PAULETTA, G PESCARA, L PHILLIPS, TJ PTOHOS, F PLUNKETT, R PONDROM, L PROUDFOOT, J PUNZI, G QUARRIE, D RAGAN, K REDLINGER, G RHOADES, J ROACH, M RIMONDI, F RISTORI, L ROBERTSON, WJ RODRIGO, T ROHALY, T ROODMAN, A SAKUMOTO, WK SANSONI, A SARD, RD SAVOYNAVARRO, A SCARPINE, V SCHLABACH, P SCHMIDT, EE SCHNEIDER, O SCHUB, MH SCHWITTERS, R SCRIBANO, A SEGLER, S SEIYA, Y SGANOS, G SHAPIRO, M SHAW, NM SHEAFF, M SHOCHET, M SIEGRIST, J SILL, A SINERVO, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD SONG, L SONG, T SPAHN, M SPIES, A SPHICAS, P STDENIS, R STANCO, L STEFANINI, A SULLIVAN, G SUMOROK, K SWARTZ, RL TAKANO, M TAKIKAWA, K TAREM, S TARTARELLI, F TETHER, S THERIOT, D TIMKO, M TIPTON, P TKACZYK, S TOLLESTRUP, A TONNISON, J TRISCHUK, W TSAY, Y TSENG, J TURINI, N UKEGAWA, F UNDERWOOD, D VEJCIK, S VIDAL, R WAGNER, RG WAGNER, RL WAINER, N WALKER, RC WALSH, J WATTS, G WATTS, T WEBB, R WENDT, C WENZEL, H WESTER, WC WESTHUSING, T WHITE, SN WICKLUND, AB WICKLUND, E WILLIAMS, HH WINER, BL WOLINSKI, J WU, D WYSS, J YAGIL, A YASUOKA, K YE, Y YEH, GP YI, C YOH, J YOKOYAMA, M YUN, JC ZANETTI, A ZETTI, F ZHANG, S ZHANG, W ZUCCHELLI, S AF ABE, F ALBROW, M AMIDEI, D ANWAYWIESE, C APOLLINARI, G ATAC, M AUCHINCLOSS, P AZZI, P BADEN, AR BACCHETTA, N BADGETT, W BAILEY, MW BAMBERGER, A DEBARBARO, P BARBAROGALTIERI, A BARNES, VE BARNETT, BA BAUER, G BAUMANN, T BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENJAMIN, D BENLLOCH, J BENSINGER, J BERETVAS, A BERGE, JP BERTOLUCCI, S BIERY, K BHADRA, S BINKLEY, M BISELLO, D BLAIR, R BLOCKER, C BODEK, A BOLOGNESI, V BOOTH, AW BOSWELL, C BRANDENBURG, G BROWN, D BUCKLEYGEER, E BUDD, HS BUSETTO, G BYONWAGNER, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CANER, A CAREY, R CARITHERS, W CARLSMITH, D CARROLL, JT CASHMORE, R CASTRO, A CERVELLI, F CHADWICK, K CHAPMAN, J CHIARELLI, G CHINOWSKY, W CIHANGIR, S CLARK, AG COBAL, M CONNOR, D CONTRERAS, M COOPER, J CORDELLI, M CRANE, D CUNNINGHAM, JD DAY, C DEJONGH, F DELLAGNELLO, S DELLORSO, M DEMORTIER, L DENBY, B DERWENT, PF DEVLIN, T DIBITONTO, D DICKSON, M DRUCKER, RB EINSWEILER, K ELIAS, JE ELY, R ENO, S ERREDE, S ETCHEGOYEN, A FARHAT, B FELDMAN, GJ FLAUGHER, B FOSTER, GW FRANKLIN, M FREEMAN, J FRISCH, H FUESS, T FUKUI, Y GARFINKEL, AF GAUTHIER, A GEER, S GERDES, DW GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GOLD, M GONZALEZ, J GOULIANOS, K GRASSMANN, H GRIECO, GM GRINDLEY, R GROSSOPILCHER, C HABER, C HAHN, SR HANDLER, R HARA, K HARRAL, B HARRIS, RM HAUGER, SA HAUSER, J HAWK, C HESSING, T HOLLEBEEK, R HOLLOWAY, L HONG, S HOUK, G HU, P HUBBARD, B HUFFMAN, BT HUGHES, R HURST, P HUTH, J HYLEN, J INCAGLI, M INO, T ISO, H JENSEN, H JESSOP, CP JOHNSON, RP JOSHI, U KADEL, RW KAMON, T KANDA, S KARDELIS, DA KARLINER, I KEARNS, E KEEBLE, L KEPHART, R KESTEN, P KEUP, RM KEUTELIAN, H KIM, D KIM, SB KIM, SH KIM, YK KIRSCH, L KONDO, K KONIGSBERG, J KORDAS, K KOVACS, E KRASBERG, M KUHLMANN, SE KUNS, E LAASANEN, AT LAMMEL, S LAMOUREUX, JI LEONE, S LEWIS, JD LI, W LIMON, P LINDGREN, M LISS, TM LOCKYER, N LORETI, M LOW, EH LUCCHESI, D LUCHINI, CB LUKENS, P MAAS, P MAESHIMA, K MANGANO, M MARRINER, JP MARIOTTI, M MARKELOFF, R MARKOSKY, LA MATTINGLY, R MCINTYRE, P MENZIONE, A MESCHI, E MEYER, T MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MIYASHITA, S MORITA, Y MOULDING, S MUELLER, J MUKHERJEE, A MULLER, T NAKAE, LF NAKANO, I NELSON, C NEUBERGER, D NEWMANHOLMES, C NG, JST NINOMIYA, M NODULMAN, L OGAWA, S PAOLETTI, R PAPADIMITRIOU, V PARA, A PARE, E PARK, S PATRICK, J PAULETTA, G PESCARA, L PHILLIPS, TJ PTOHOS, F PLUNKETT, R PONDROM, L PROUDFOOT, J PUNZI, G QUARRIE, D RAGAN, K REDLINGER, G RHOADES, J ROACH, M RIMONDI, F RISTORI, L ROBERTSON, WJ RODRIGO, T ROHALY, T ROODMAN, A SAKUMOTO, WK SANSONI, A SARD, RD SAVOYNAVARRO, A SCARPINE, V SCHLABACH, P SCHMIDT, EE SCHNEIDER, O SCHUB, MH SCHWITTERS, R SCRIBANO, A SEGLER, S SEIYA, Y SGANOS, G SHAPIRO, M SHAW, NM SHEAFF, M SHOCHET, M SIEGRIST, J SILL, A SINERVO, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD SONG, L SONG, T SPAHN, M SPIES, A SPHICAS, P STDENIS, R STANCO, L STEFANINI, A SULLIVAN, G SUMOROK, K SWARTZ, RL TAKANO, M TAKIKAWA, K TAREM, S TARTARELLI, F TETHER, S THERIOT, D TIMKO, M TIPTON, P TKACZYK, S TOLLESTRUP, A TONNISON, J TRISCHUK, W TSAY, Y TSENG, J TURINI, N UKEGAWA, F UNDERWOOD, D VEJCIK, S VIDAL, R WAGNER, RG WAGNER, RL WAINER, N WALKER, RC WALSH, J WATTS, G WATTS, T WEBB, R WENDT, C WENZEL, H WESTER, WC WESTHUSING, T WHITE, SN WICKLUND, AB WICKLUND, E WILLIAMS, HH WINER, BL WOLINSKI, J WU, D WYSS, J YAGIL, A YASUOKA, K YE, Y YEH, GP YI, C YOH, J YOKOYAMA, M YUN, JC ZANETTI, A ZETTI, F ZHANG, S ZHANG, W ZUCCHELLI, S TI PROMPT PHOTON CROSS-SECTION MEASUREMENT IN (P)OVER-BARP COLLISIONS AT ROOT-S = 1.8 TEV SO PHYSICAL REVIEW D LA English DT Article ID CERN PBARP COLLIDER; GLUON DISTRIBUTION; CONSTRUCTION; CHAMBER; DESIGN; JET AB The first prompt photon measurement from the CDF experiment at the Fermilab ppBAR Collider is presented. Two independent methods are used to measure the cross section: one for high transverse momentum (P(T)) and one for lower P(T). Comparisons to various theoretical calculations are shown. The. cross section agrees qualitatively with QCD calculations but has a steeper slope at low P(T). C1 BRANDEIS UNIV,WALTHAM,MA 02254. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60637. DUKE UNIV,DURHAM,NC 27706. ARGONNE NATL LAB,ARGONNE,IL 60439. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,LAB NAZL FRASCATI,FRASCATI,ITALY. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV ILLINOIS,URBANA,IL 61801. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. UNIV PADUA,INST NAZL FIS NUCL,I-35131 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. RUTGERS UNIV,PISCATAWAY,NJ 08854. TEXAS A&M UNIV SYST,COLL STN,TX 77843. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. ROCKEFELLER UNIV,NEW YORK,NY 10021. RP ABE, F (reprint author), NATL LAB HIGH ENERGY PHYS,OHO,IBARAKI 305,JAPAN. RI St.Denis, Richard/C-8997-2012; Chiarelli, Giorgio/E-8953-2012; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Kim, Soo-Bong/B-7061-2014 OI Chiarelli, Giorgio/0000-0001-9851-4816; Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; NR 41 TC 67 Z9 67 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1993 VL 48 IS 7 BP 2998 EP 3025 DI 10.1103/PhysRevD.48.2998 PG 28 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300008 ER PT J AU AKCHURIN, N LANGLAND, J ONEL, Y BONNER, BE CORCORAN, MD CRANSHAW, J NESSITEDALDI, F NESSI, M NGUYEN, C ROBERTS, JB SKEENS, J WHITE, JL BRAVAR, A GIACOMICH, R PENZO, A SCHIAVON, P ZANETTI, A BYSTRICKY, J LEHAR, F DELESQUEN, A VANROSSUM, L COSSAIRT, JD READ, AL DEREVSCHIKOV, AA MATULENKO, YA MESCHANIN, AP NURUSHEV, SB PATALAKHA, DI RYKOV, VL SOLOVYANOV, VL VASILIEV, AN GROSNICK, DP HILL, DA LAGHAI, M LOPIANO, D OHASHI, Y SHIMA, T SPINKA, H STANEK, RW UNDERWOOD, DG YOKOSAWA, A FUNAHASHI, H GOTO, Y IMAI, K ITOW, Y MAKINO, S MASAIKE, A MIYAKE, K NAGAMINE, T SAITO, N YAMASHITA, S IWATANI, K KURODA, K MICHALOWICZ, A LUEHRING, FC MILLER, DH MAKI, T PAULETTA, G RAPPAZZO, GF SALVATO, G TAKASHIMA, R TAKEUTCHI, F AF AKCHURIN, N LANGLAND, J ONEL, Y BONNER, BE CORCORAN, MD CRANSHAW, J NESSITEDALDI, F NESSI, M NGUYEN, C ROBERTS, JB SKEENS, J WHITE, JL BRAVAR, A GIACOMICH, R PENZO, A SCHIAVON, P ZANETTI, A BYSTRICKY, J LEHAR, F DELESQUEN, A VANROSSUM, L COSSAIRT, JD READ, AL DEREVSCHIKOV, AA MATULENKO, YA MESCHANIN, AP NURUSHEV, SB PATALAKHA, DI RYKOV, VL SOLOVYANOV, VL VASILIEV, AN GROSNICK, DP HILL, DA LAGHAI, M LOPIANO, D OHASHI, Y SHIMA, T SPINKA, H STANEK, RW UNDERWOOD, DG YOKOSAWA, A FUNAHASHI, H GOTO, Y IMAI, K ITOW, Y MAKINO, S MASAIKE, A MIYAKE, K NAGAMINE, T SAITO, N YAMASHITA, S IWATANI, K KURODA, K MICHALOWICZ, A LUEHRING, FC MILLER, DH MAKI, T PAULETTA, G RAPPAZZO, GF SALVATO, G TAKASHIMA, R TAKEUTCHI, F TI ANALYZING POWER MEASUREMENT OF PP ELASTIC-SCATTERING IN THE COULOMB-NUCLEAR INTERFERENCE REGION WITH THE 200-GEV/C POLARIZED-PROTON BEAM AT FERMILAB SO PHYSICAL REVIEW D LA English DT Article ID CROSS-SECTION; GEV-C; ENERGY AB The analyzing power A(N) Of proton-proton elastic scattering in the Coulomb-nuclear interference region has been measured using the 200-GeV/c Fermilab polarized proton beam. A theoretically predicted interference between the hadronic non-spin-flip amplitude and the electromagnetic spin-flip amplitude is shown for the first time to be present at high energies in the region of 1.5 X 10(-3) to 5.0 X 10(-2) (GeV/c)2 four-momentum transfer squared, and our results are analyzed in connection with theoretical calculations. In addition, the role of possible contributions of the hadronic spin-flip amplitude is discussed. C1 RICE UNIV,T W BONNER NUCL LAB,HOUSTON,TX 77251. IST NAZL FIS NUCL,SEZ TRIESTE,TRIESTE,ITALY. CENS,DAPNIA,SPP,F-91191 GIF SUR YVETTE,FRANCE. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. SERPUKHOV HIGH ENERGY PHYS INST,SERPUKHOV,RUSSIA. ARGONNE NATL LAB,ARGONNE,IL 60439. KYOTO UNIV,DEPT PHYS,KYOTO 606,JAPAN. HIROSHIMA UNIV,HIROSHIMA 724,JAPAN. LAB PHYS PARTICULES,F-74017 ANNECY LE VIEUX,FRANCE. NORTHWESTERN UNIV,DEPT PHYS,EVANSTON,IL 60201. UNIV OCCUPAT & ENVIRONM HLTH,KITAKYUSHU,FUKUOKA 807,JAPAN. UNIV UDINE,IST FIS,I-33100 UDINE,ITALY. INFN,COLL GRP,I-98100 MESSINA,ITALY. UNIV MESSINA,DIPARTIMENTO FIS,I-98100 MESSINA,ITALY. KYOTO UNIV,KYOTO 612,JAPAN. KYOTO SANGYO UNIV,KYOTO 612,JAPAN. RP AKCHURIN, N (reprint author), UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242, USA. NR 29 TC 41 Z9 41 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 OCT 1 PY 1993 VL 48 IS 7 BP 3026 EP 3036 DI 10.1103/PhysRevD.48.3026 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300009 ER PT J AU ARMSTRONG, TA BETTONI, D BHARADWAJ, V BIINO, C BORREANI, G BROEMMELSIEK, D BUZZO, A CALABRESE, R CECCUCCI, A CESTER, R CHURCH, MD DALPIAZ, P DALPIAZ, PF DIBENEDETTO, R DIMITROYANNIS, D FABBRI, MG FAST, JE GIANOLI, A GINSBURG, CM GOLLWITZER, KE HAHN, AA HASAN, MA HSUEH, SY LEWIS, RA LUPPI, E MACRI, M MAJEWSKA, AM MANDELKERN, MA MARCHETTO, F MARINELLI, M MARQUES, JL MARSH, W MARTINI, M MASUZAWA, M MENICHETTI, E MIGLIORI, A MUSSA, R PALESTINI, S PALLAVICINI, M PASTRONE, N PATRIGNANI, C PEOPLES, J PESANDO, L PETRUCCI, F PIA, MG PORDES, S RAPIDIS, PA RAY, RE REID, JD RINAUDO, G ROCCUZZO, B ROSEN, JL SANTRONI, A SARMIENTO, M SAVRIE, M SCALISI, A SCHULTZ, J SETH, KK SMITH, A SMITH, GA SOZZI, M TROKENHEIM, S WEBER, MF WERKEMA, SJ ZHANG, Y ZHAO, JL ZIOULAS, G AF ARMSTRONG, TA BETTONI, D BHARADWAJ, V BIINO, C BORREANI, G BROEMMELSIEK, D BUZZO, A CALABRESE, R CECCUCCI, A CESTER, R CHURCH, MD DALPIAZ, P DALPIAZ, PF DIBENEDETTO, R DIMITROYANNIS, D FABBRI, MG FAST, JE GIANOLI, A GINSBURG, CM GOLLWITZER, KE HAHN, AA HASAN, MA HSUEH, SY LEWIS, RA LUPPI, E MACRI, M MAJEWSKA, AM MANDELKERN, MA MARCHETTO, F MARINELLI, M MARQUES, JL MARSH, W MARTINI, M MASUZAWA, M MENICHETTI, E MIGLIORI, A MUSSA, R PALESTINI, S PALLAVICINI, M PASTRONE, N PATRIGNANI, C PEOPLES, J PESANDO, L PETRUCCI, F PIA, MG PORDES, S RAPIDIS, PA RAY, RE REID, JD RINAUDO, G ROCCUZZO, B ROSEN, JL SANTRONI, A SARMIENTO, M SAVRIE, M SCALISI, A SCHULTZ, J SETH, KK SMITH, A SMITH, GA SOZZI, M TROKENHEIM, S WEBER, MF WERKEMA, SJ ZHANG, Y ZHAO, JL ZIOULAS, G TI STUDY OF THE ANGULAR-DISTRIBUTION OF THE REACTION (P)OVER-BARP-]CHI-C2-]J/PSI-GAMMA-]E+E-GAMMA SO PHYSICAL REVIEW D LA English DT Article ID ALUMINIZED MYLAR TUBES; CHARMONIUM STATES; CHARGE DIVISION; MASSLESS QCD; DECAYS; ANNIHILATION; TRANSITIONS; CALORIMETER; QUARKONIA; CHAMBER AB We report on a study of the angular distribution in the reaction ppBAR --> chi(c2) --> J/psi gamma --> e+e-gamma. Using a sample of 1904 events, we find that the contribution of helicity zero in the formation process is B-0(2) < 0.22 (90% C.L.), and that the normalized quadrupole amplitude in the radiative decay is a2 = -0.14 +/- 0.06. The normalized radiative decay octupole amplitude a3 is found to be consistent with zero. C1 IST NAZL FIS NUCL,I-44100 FERRARA,ITALY. IST NAZL FIS NUCL,I-16146 GENOA,ITALY. NORTHWESTERN UNIV,EVANSTON,IL 60208. IST NAZL FIS NUCL,I-10125 TURIN,ITALY. UNIV TURIN,I-10125 TURIN,ITALY. UNIV GENOA,I-16146 GENOA,ITALY. UNIV FERRARA,I-44100 FERRARA,ITALY. UNIV CALIF IRVINE,IRVINE,CA 92717. PENN STATE UNIV,UNIV PK,PA 16802. RP ARMSTRONG, TA (reprint author), FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. RI Pia, Maria Grazia/C-7034-2012; Sozzi, Marco/H-1674-2011; Patrignani, Claudia/C-5223-2009; Luppi, Eleonora/A-4902-2015; Calabrese, Roberto/G-4405-2015; Pallavicini, Marco/G-5500-2012; Gianoli, Alberto/H-5544-2015 OI Pia, Maria Grazia/0000-0002-3579-9639; Sozzi, Marco/0000-0002-2923-1465; Patrignani, Claudia/0000-0002-5882-1747; Luppi, Eleonora/0000-0002-1072-5633; Calabrese, Roberto/0000-0002-1354-5400; Pallavicini, Marco/0000-0001-7309-3023; Gianoli, Alberto/0000-0002-2456-8667 NR 43 TC 36 Z9 36 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 OCT 1 PY 1993 VL 48 IS 7 BP 3037 EP 3044 DI 10.1103/PhysRevD.48.3037 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300010 ER PT J AU PIERCE, D AF PIERCE, D TI ANOMALOUS PROMPT PHOTON PRODUCTION IN HADRONIC COLLISIONS AT LOW CHI-T SO PHYSICAL REVIEW D LA English DT Article ID PP COLLISIONS; COLLIDER; MOMENTUM AB We investigate the discrepancy that exists at low X(T) = 2p(T)/square-root s between the next-to-leading-order QCD calculations of prompt photon production and the measured cross section. The central values of the measured cross section are of order 100% larger than QCD predictions in this region. It has been suggested that the bremsstrahlung contribution may account for this discrepancy. The quark fragmentation function D(gamma/q)(z) has not been measured and an exactly known asymptotic form is normally used in calculations. We examine the effect of much larger fragmentation functions on the QCD predictions. After illustrating the effect of the large fragmentation functions in some detail for recent CDF data at square-root s =1.8 TeV, we perform a chi2 fit to eight prompt photon data sets ranging in c.m.s. energy from 24 GeV to 1.8 TeV. While a large fragmentation function normalization may prove to play an important role in resolving the discrepancy, the present theoretical and experimental uncertainties prevent the determination of any definite normalization value. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. NR 14 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1993 VL 48 IS 7 BP 3121 EP 3127 DI 10.1103/PhysRevD.48.3121 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300021 ER PT J AU LU, HJ BRODSKY, SJ AF LU, HJ BRODSKY, SJ TI RELATING PHYSICAL OBSERVABLES IN QCD USING THE EXTENDED RENORMALIZATION-GROUP METHOD SO PHYSICAL REVIEW D LA English DT Article ID INVARIANT PERTURBATION-THEORY; BJORKEN SUM-RULE; EFFECTIVE CHARGES; E+E ANNIHILATION; CROSS-SECTION; QUANTUM CHROMODYNAMICS; FIELD-THEORIES; AMBIGUITIES AB We discuss the Stuckelberg-Peterman extended renormalization group equations in perturbative QCD, which express the invariance of physical observables under renormalization-scale and scheme-parameter transformations. We introduce a universal coupling function that covers all possible choices of scale and scheme. Any perturbative series in QCD is shown to be equivalent to a particular point in this function. This function can be computed from a set of first-order differential equations involving the extended beta functions. We propose the use of these evolution equations instead of a perturbative series for numerical evaluation of physical observables. This formalism is free of scale-scheme ambiguity and allows a reliable error analysis of higher-order corrections. It also provides a precise definition for LAMBDA(MSBAR) as the pole in the associated 't Hooft scheme. A concrete application to R(e+e--->hadrons) is presented. C1 STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP LU, HJ (reprint author), UNIV MARYLAND,DEPT PHYS,COLL PK,MD 20742, USA. NR 38 TC 22 Z9 22 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 OCT 1 PY 1993 VL 48 IS 7 BP 3310 EP 3318 DI 10.1103/PhysRevD.48.3310 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300042 ER PT J AU GUPTA, R DANIEL, D GRANDY, J AF GUPTA, R DANIEL, D GRANDY, J TI BETHE-SALPETER AMPLITUDES AND DENSITY CORRELATIONS FOR MESONS WITH WILSON FERMIONS SO PHYSICAL REVIEW D LA English DT Article ID LATTICE QCD; CONFINEMENT AB We present an investigation of various gauge-invariant definitions of the qqBAR Bethe-Salpeter (BS) amplitude for mesons in lattice QCD, and compare them to the Coulomb and Landau gauge BS amplitudes. We show that the gauge-invariant BS amplitude is considerably broadened by the use of ''fat'' gauge links (constructed by smearing the links of the original lattice). A qualitative demonstration of the Lorentz contraction of the pion wave function at nonzero momentum is given. We also calculate density-density correlations and discuss the limitations in extracting the charge radius of the pion from these observables. Lastly, the polarization dependence of the BS amplitude for the p meson is exhibited, and we extract the relative admixture of l = 0 and l = 2 states showing that simple hydrogenlike wave functions provide a good fit. RP LOS ALAMOS NATL LAB, MS-B285, T-8, LOS ALAMOS, NM 87545 USA. NR 22 TC 39 Z9 39 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1993 VL 48 IS 7 BP 3330 EP 3339 DI 10.1103/PhysRevD.48.3330 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300044 ER PT J AU CHU, MC GRANDY, JM HUANG, S NEGELE, JW AF CHU, MC GRANDY, JM HUANG, S NEGELE, JW TI CORRELATION-FUNCTIONS OF HADRON CURRENTS IN THE QCD VACUUM CALCULATED IN LATTICE QCD SO PHYSICAL REVIEW D LA English DT Article AB Point-to-point vacuum correlation functions for spatially separated hadron currents are calculated in quenched lattice QCD on a 16(3) x 24 lattice with 6/g = 5.7. The lattice data are analyzed in terms of dispersion relations, which enable us to extract physical information from small distances where asymptotic freedom is apparent to large distances where the hadronic resonances dominate. In the pseudoscalar, vector, and axial vector channels where experimental data or phenomenological information are available, semiquantitative agreement is obtained. In the nucleon and DELTA channels, where no experimental data exist, our lattice data complement experiments. Comparison with approximations based on sum rules and interacting instantons are made, and technical details of the lattice calculation are described. C1 LOS ALAMOS NATL LAB,GRP T8,LOS ALAMOS,NM 87545. UNIV WASHINGTON,DEPT PHYS,SEATTLE,WA 98195. MIT,CTR THEORET PHYS,NUCL SCI LAB,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP CHU, MC (reprint author), CALTECH,W K KELLOGG RADIAT LAB,106-38,PASADENA,CA 91125, USA. NR 14 TC 68 Z9 68 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 OCT 1 PY 1993 VL 48 IS 7 BP 3340 EP 3353 DI 10.1103/PhysRevD.48.3340 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MC123 UT WOS:A1993MC12300045 ER PT J AU CHEN, P NG, CK RAJAGOPALAN, S AF CHEN, P NG, CK RAJAGOPALAN, S TI LUMINOSITY ENHANCEMENT BY A SELF-IONIZED PLASMA IN E+E- COLLISIONS SO PHYSICAL REVIEW E LA English DT Article ID LENS AB We employ a two-dimensional particle-in-cell code to investigate the focusing of relativistic charged-particle beams in plasmas. The intense electric fields generated by electron and positron beams in high-energy physics experiments can ionize a gas into a plasma which will then focus the beams. The self-ionization mechanism will enhance the luminosity in e+e- collisions by implementing a plasma lens in the interaction region. We investigate the dependences of the luminosity enhancement on the plasma lens thickness and plasma density. The application of plasma lens focusing to the Stanford Linear Collider is discussed. C1 UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. RP CHEN, P (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1993 VL 48 IS 4 BP 3022 EP 3029 DI 10.1103/PhysRevE.48.3022 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ME593 UT WOS:A1993ME59300083 ER PT J AU LEE, SY NG, KY TRBOJEVIC, D AF LEE, SY NG, KY TRBOJEVIC, D TI MINIMIZING DISPERSION IN FLEXIBLE-MOMENTUM-COMPACTION LATTICES SO PHYSICAL REVIEW E LA English DT Article AB Medium-energy accelerators are often confronted with problems during transition energy crossing, such as longitudinal microwave instability and nonlinear synchrotron motion. These problems can be avoided by an accelerator having a negative momentum-compaction factor. A modular method for designing a lattice with adjustable momentum-compaction factor is presented. The dispersion excursion of the basic flexible-momentum-compaction module can be minimized to less than the maximum dispersion of the focusing-defocusing (FODO) lattice containing the same FODO cells. The phase advance of the module can be adjusted to be an odd multiple of quarter betatron waves. We found that a lattice composed of such modules possesses excellent chromatic properties with excellent tunability, smaller systematic stop-band widths, and smaller sextupole distortion functions. C1 INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405. RP LEE, SY (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 16 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 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1993 VL 48 IS 4 BP 3040 EP 3048 DI 10.1103/PhysRevE.48.3040 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ME593 UT WOS:A1993ME59300085 ER PT J AU GREENE, JW AF GREENE, JW TI PARAXIAL WAVE-OPTICS SIMULATION OF X-RAY LASERS SO PHYSICAL REVIEW E LA English DT Article ID PROPAGATION; COHERENCE; EQUATION AB Paraxial wave-optics models of x-ray lasers include diffraction, time dependence, a stochastic description of spontaneous emission, two-way waves coupled by a saturable nonuniform gain, and refraction due to a nonuniform charge density. Standard algorithms for this modeling tax the speed and storage of a supercomputer. Recent work, using such algorithms on an overly coarse grid, has very distorted near fields, too wide far fields, and an optimistic estimation of spatial coherence. This paper develops axial shooting-secant iterations that feature coarse-grid storage of fields, refined-axial-step standard-algorithm shooting between coarse-grid data, and improved coarse-grid approximations via secant estimation. Such calculations, effective when the charge density and gain vary much more transversely than axially, save time and much storage. High-accuracy integral Hermitian methods for the transverse discretization are also introduced and provide several advantages in comparisions with standard finite differences, discrete Fourier transforms, and Gauss-Hermite or Gauss-Laguerre expansions. Several well-converged x-ray-laser calculations are presented. A slightly greater gain along certain curved paths contributes much less than refraction to prominent maxima in the far-field wings. Discrete computation inherently underestimates diffraction and thereby overestimates power output. Refraction enhances the evolution of single-mode-like intensity whereas saturation of the gain inhibits this process. The fields are sensitive to the transverse profiles of the charge density and small-signal gain. Although refraction leads to many more transverse modes, it improves spatial coherence. RP GREENE, JW (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV COMPUTAT PHYS,LIVERMORE,CA 94550, USA. NR 25 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1993 VL 48 IS 4 BP 3130 EP 3160 DI 10.1103/PhysRevE.48.3130 PG 31 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ME593 UT WOS:A1993ME59300098 ER PT J AU HOOVER, WG HOLIAN, BL POSCH, HA AF HOOVER, WG HOLIAN, BL POSCH, HA TI POSSIBLE EXPERIMENT TO CHECK THE REALITY OF A NONEQUILIBRIUM TEMPERATURE - COMMENT-I SO PHYSICAL REVIEW E LA English DT Letter ID DYNAMICS; BULK AB We comment on a recent paper by Jou and Casas-Vazquez [Phys. Rev. A 45, 8371 (1992)] from our perspective of classical computer simulation. We emphasize and discuss the utility of the ideal-gas temperature scale of kinetic theory in describing systems far from equilibrium. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV VIENNA,A-1090 VIENNA,AUSTRIA. RP HOOVER, WG (reprint author), UNIV CALIF DAVIS,LIVERMORE,CA 94550, USA. NR 14 TC 36 Z9 36 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1993 VL 48 IS 4 BP 3196 EP 3198 DI 10.1103/PhysRevE.48.3196 PG 3 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ME593 UT WOS:A1993ME59300109 ER PT J AU FACTOR, BJ LEE, LT KENT, MS RONDELEZ, F AF FACTOR, BJ LEE, LT KENT, MS RONDELEZ, F TI OBSERVATION OF CHAIN STRETCHING IN LANGMUIR DIBLOCK COPOLYMER MONOLAYERS SO PHYSICAL REVIEW E LA English DT Note ID GRAFTED POLYMER BRUSH; DENSITY PROFILE; NEUTRON REFLECTIVITY; BLOCK COPOLYMERS; ADSORPTION; INTERFACE AB We report observations of chain stretching in diblock copolymer monolayers on the surface of a selective solvent. Using neutron reflectivity, we have studied the concentration profile of the submerged block over a large range of surface density sigma (chains per area) for two different molecular weights. The observed increase in the layer thickness is weaker than the sigma 1/3 prediction of mean-field and scaling theories for the limiting behavior, but is in agreement with recent numerical self-consistent-field calculations by Whitmore and Noolandi [Macromolecules 23, 3321 (1990)]. C1 SANDIA NATL LABS,DEPT 1815,POB 5800,ALBUQUERQUE,NM 87185. INST CURIE,PHYS & CHIM SECT,PHYSICOCHIM SURFACES & INTERFACES LAB,F-75005 PARIS,FRANCE. CENS,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. NR 19 TC 34 Z9 34 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1993 VL 48 IS 4 BP R2354 EP R2357 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ME593 UT WOS:A1993ME59300008 ER PT J AU VIECELLI, JA AF VIECELLI, JA TI STATISTICAL-MECHANICS AND CORRELATION-PROPERTIES OF A ROTATING 2-DIMENSIONAL FLOW OF LIKE-SIGN VORTICES SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID LAGRANGIAN TURBULENCE; PHASE-TRANSITIONS; 2 DIMENSIONS; DYNAMICS AB The Hamiltonian flow of a set of point vortices of like sign and strength has a low-temperature phase consisting of a rotating triangular lattice of vortices, and a normal temperature turbulent phase consisting of random clusters of vorticity that orbit about a common center along random tracks. The mean-field flow in the normal temperature phase has similarities with turbulent quasi-two-dimensional rotating laboratory and geophysical flows, whereas the low-temperature phase displays effects associated with quantum fluids. In the normal temperature phase the vortices follow power-law clustering distributions, while iii the time domain random interval modulation of the vortex orbit radii fluctuations produces singular fractional exponent power-law low-frequency spectra corresponding to time autocorrelation functions with fractional exponent power-law tails. Enhanced diffusion is present in the turbulent state, whereas in the solid-body rotation state vortices thermally diffuse across the lattice. Over the entire temperature range the interaction energy of a single vortex in the field of the rest of the vortices follows positive temperature Fermi-Dirac statistics, with the zero temperature limit corresponding to the rotating crystal phase, and the infinite temperature limit corresponding to a Maxwellian distribution. Analyses of weather records dependent on the large-scale quasi-two-dimensional atmospheric circulation suggest the presence of singular fractional exponent power-law spectra and fractional exponent power-law autocorrelation tails, consistent with the theory. RP VIECELLI, JA (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 38 TC 12 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD OCT PY 1993 VL 5 IS 10 BP 2484 EP 2501 DI 10.1063/1.858762 PG 18 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LY677 UT WOS:A1993LY67700016 ER PT J AU GRUNAU, D CHEN, SY EGGERT, K AF GRUNAU, D CHEN, SY EGGERT, K TI A LATTICE BOLTZMANN MODEL FOR MULTIPHASE FLUID-FLOWS SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID NAVIER-STOKES EQUATION; GAS AUTOMATA; IMMISCIBLE FLUIDS; DYNAMICS AB A lattice Boltzmann equation method for simulating multiphase immiscible fluid flows with variation of density and viscosity. based on the model proposed by Gunstensen et al. for two-component immiscible fluids [Phys. Rev A 43. 4320 (1991)] is developed. The numerical measurements of surface tension and viscosity agree well with theoretical predictions. Several basic numerical tests, including spinodal decomposition, two-phase fluid flows in two-dimensional channels, and two-phase viscous fingering, are shown in agreement of experiments and analytical solutions. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP GRUNAU, D (reprint author), LOS ALAMOS NATL LAB,DIV EARTH & ENVIRONM SCI,LOS ALAMOS,NM 87545, USA. RI Chen, Shiyi/A-3234-2010 NR 26 TC 196 Z9 208 U1 0 U2 26 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD OCT PY 1993 VL 5 IS 10 BP 2557 EP 2562 DI 10.1063/1.858769 PG 6 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LY677 UT WOS:A1993LY67700023 ER PT J AU BOWMAN, JC KROMMES, JA OTTAVIANI, M AF BOWMAN, JC KROMMES, JA OTTAVIANI, M TI THE REALIZABLE MARKOVIAN CLOSURE .1. GENERAL-THEORY, WITH APPLICATION TO 3-WAVE DYNAMICS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Review ID DIRECT-INTERACTION APPROXIMATION; RIGOROUS UPPER-BOUNDS; FLUCTUATION-DISSIPATION; PLASMA TURBULENCE; 2-DIMENSIONAL TURBULENCE; STATISTICAL DYNAMICS; ISOTROPIC TURBULENCE; PASSIVE ADVECTION; SIMPLE-MODELS; TRANSPORT AB A type of eddy-damped quasinormal Markovian (EDQNM) closure is shown to be potentially nonrealizable in the presence of linear wave phenomena. This statistical closure results from the application of a fluctuation-dissipation (FD) ansatz to the direct-interaction approximation (DIA); unlike in phenomenological formulations of the. EDQNM, both the frequency and the damping rate are renormalized. A violation of realizability can have serious physical consequences, including the prediction of negative or even divergent energies. A new statistical approximation, the realizable Markovian closure (RMC), is proposed as a remedy. An underlying Langevin equation that makes no assumption of white-noise statistics is exhibited. Even in the wave-free case the RMC, which is based on a nonstationary version of the FD ansatz, provides a better representation of the true dynamics than does the EDQNM closure. The closure solutions are compared numerically against the exact ensemble dynamics of three interacting waves. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. NR 78 TC 65 Z9 65 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 OCT PY 1993 VL 5 IS 10 BP 3558 EP 3589 DI 10.1063/1.860829 PG 32 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400010 ER PT J AU SHAING, KC HSU, CT AF SHAING, KC HSU, CT TI EFFECTS OF ION DIAMAGNETIC FLOW ON SHOCK FORMATION IN POLOIDALLY ROTATING TOKAMAK PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID EDGE ELECTRIC-FIELD; L-H TRANSITION; MODE; GEOMETRY AB When the poloidal ion diamagnetic flow is of the order of the EXB drift velocity, it significantly affects the shock formation in a poloidally rotating tokamak plasma. (Here, E is the electric field and B is the magnetic field.) The poloidal density variation in both linear and shock regimes can be weakened if the poloidal ion diamagnetic flow tends to cancel the poloidal EXB flow. The magnitude of the density variation is not symmetric with respect to the direction of the EXB poloidal rotation. The resonant condition at which strong shock occurs is also modified dramatically by the diamagnetic flow. For some cases, the poloidal density variation inside the bifurcated electric field layer in the L-H transition [Phys. Rev. Lett. 42, 1408 (1982)] may not be large enough to significantly modify the plasma viscosity obtained by neglecting the compressibility effects. C1 MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. RP SHAING, KC (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 24 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD OCT PY 1993 VL 5 IS 10 BP 3596 EP 3602 DI 10.1063/1.860831 PG 7 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400012 ER PT J AU KISSICK, MW EFTHIMION, PC MANSFIELD, DK CALLEN, JD BUSH, CE PARK, HK SCHIVELL, J SYNAKOWSKI, EJ TAYLOR, G AF KISSICK, MW EFTHIMION, PC MANSFIELD, DK CALLEN, JD BUSH, CE PARK, HK SCHIVELL, J SYNAKOWSKI, EJ TAYLOR, G TI DOMINANCE OF CONVECTIVE HEAT-TRANSPORT IN THE CORE OF TFTR (TOKAMAK FUSION TEST REACTOR) SUPERSHOT PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article AB Using perturbations in electron density and temperature induced by small helium gas puffs in TFTR (Tokamak Fusion Test Reactor) [Plasma Phys. Controlled Nucl. Fusion Res. 1, 51 (1986)], the dominance of convective heat transport in the core (r/a<0.4) of supershot plasmas has been demonstrated in a new way. The TRANSP [J. Comput. Phys. 43, 61 (1981)] transport code was used to calculate the time-dependent particle and heat fluxes. Perturbations in the calculated convective and total electron heat fluxes were compared. They demonstrate that the conductive component decreases moving into the supershot core, and the convective component dominates in the supershot core. These results suggest a different transport drive in the supershot core compared to that in the rest of the supershot plasma. C1 UNIV WISCONSIN,MADISON,WI 53706. RP KISSICK, MW (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 14 TC 5 Z9 5 U1 1 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 OCT PY 1993 VL 5 IS 10 BP 3618 EP 3621 DI 10.1063/1.860833 PG 4 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400014 ER PT J AU BARNES, DC NEBEL, RA TURNER, L AF BARNES, DC NEBEL, RA TURNER, L TI PRODUCTION AND APPLICATION OF DENSE PENNING TRAP PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article AB A new paradigm for producing well-confined, dense-thermonuclear plasmas is described. The convergence of a radial beam distribution of a Penning-trap-confined plasma produces a dense inertially confined non-neutral plasma. The equilibrium, stability, classical transport, and particle-handling properties of such a concept are developed. The application of this approach to controlled fusion using a pure electron plasma to form a central virtual cathode in which ions are electrostatically confined is discussed. On one hand, extreme plasma control is required, placing the major uncertainty on issues of machine precision. On the other hand, development is characterized by the manufacture and testing of extremely small and inexpensive systems. Thus, it would seem that a timely experimental test of this concept would be ineluctable. Success at such experiments might indicate an alternate path to practical fusion applications. RP BARNES, DC (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 15 TC 25 Z9 25 U1 1 U2 3 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 OCT PY 1993 VL 5 IS 10 BP 3651 EP 3660 DI 10.1063/1.860837 PG 10 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400018 ER PT J AU ZONCA, F CHEN, L AF ZONCA, F CHEN, L TI THEORY OF CONTINUUM DAMPING OF TOROIDAL ALFVEN EIGENMODES IN FINITE-BETA TOKAMAKS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID FUSION ALPHA-PARTICLES; BALLOONING MODES; TOROIDICITY; EXCITATION; WAVES; STABILITY; PLASMA; DESTABILIZATION; INSTABILITIES; IONS AB A general theoretical approach has been formulated for analyzing two-dimensional structures of high-n toroidal Alfven eigenmodes (TAE) in large aspect-ratio, finite-beta tokamaks. Here, n is the toroidal wave number and beta is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures, as well as finite coupling between discrete and continuous spectra. Employing the well-known (s,alpha) model equilibrium and assuming a linear equilibrium profile, the present approach has been applied to the calculation of the resonant continuum damping rate of TAE modes. Here, s and alpha denote, respectively, the strengths of magnetic shear and pressure gradients. In particular, it is found that there exists a critical alpha value, alpha(c)(s), such that, as alpha --> alpha(c), the continuum damping rate is significantly enhanced and, thus, could suppress the potential TAE instability. C1 ENEA FUS,ASSOC EURATOM,I-00044 FRASCATI,ITALY. PRINCETON UNIV,DEPT ASTROPHYS SCI,PRINCETON,NJ 08543. RP ZONCA, F (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. RI chen, liu/I-2297-2013; Zonca, Fulvio/I-8236-2016 OI Zonca, Fulvio/0000-0002-9270-4704 NR 52 TC 60 Z9 60 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 OCT PY 1993 VL 5 IS 10 BP 3668 EP 3690 DI 10.1063/1.860839 PG 23 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400020 ER PT J AU ONO, Y MORITA, A KATSURAI, M YAMADA, M AF ONO, Y MORITA, A KATSURAI, M YAMADA, M TI EXPERIMENTAL INVESTIGATION OF 3-DIMENSIONAL MAGNETIC RECONNECTION BY USE OF 2 COLLIDING SPHEROMAKS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PLASMA AB Experimental investigation of three-dimensional (3-D) effects of magnetic reconnection dynamics has been extended by use of axially colliding spheromaks [M. Yamada et al, Phys. Fluids B 3, 2379 (199 1)]. The two toroidal shape spheromak plasmas with major radii of 15-20 cm and with parallel toroidal currents of up to 30 kA collide to merge in an external equilibrium field. It is important to note that the present experimental setup allows one to investigate magnetic reconnection comprehensively from both local and global points of view. Reconnection angle theta between the merging field lines is varied by changing the polarity of the internal toroidal field and the magnitude of an external toroidal field. It is observed that the speed of counterhelicity merging with theta approximately 180-degrees is about three times faster than that of cohelicity merging with theta approximately 90-degrees. This suggests the significance of a 3-D effect on the reconnection process. This difference is attributed to the property of the neutral current sheets with and without the magnetic field component parallel to the reconnection (X) line. In the counterhelicity merging, the neutral current sheet is compressed in much shorter time than in the cohelicity merging, resulting in much higher current density and subsequent faster decay of the current sheet. This induces a faster magnetic reconnection. The reconnection speed increases proportionally with the initial approaching speed of the spheromaks, suggesting that a compressible driven reconnection model is consistent with the present reconnection experimental results. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP ONO, Y (reprint author), UNIV TOKYO,FAC ENGN,DEPT ELECT ENGN,7-3-1 HONGO,BUNKYO KU,TOKYO 113,JAPAN. RI Yamada, Masaaki/D-7824-2015 OI Yamada, Masaaki/0000-0003-4996-1649 NR 29 TC 99 Z9 100 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 OCT PY 1993 VL 5 IS 10 BP 3691 EP 3701 DI 10.1063/1.860840 PG 11 WC Physics, Fluids & Plasmas SC Physics GA MC104 UT WOS:A1993MC10400021 ER PT J AU SIEGEL, RW AF SIEGEL, RW TI EXPLORING MESOSCOPIA - THE BOLD NEW-WORLD OF NANOSTRUCTURES SO PHYSICS TODAY LA English DT Article ID GIANT MAGNETORESISTANCE; NANOCRYSTALLINE PALLADIUM; ICOSAHEDRAL STRUCTURE; HYDROGENATED COBALT; NANOPHASE TIO2; CLUSTERS; NANOINDENTATION; SUPERLATTICE; SURFACE; CU RP ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 37 TC 113 Z9 113 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0031-9228 EI 1945-0699 J9 PHYS TODAY JI Phys. Today PD OCT PY 1993 VL 46 IS 10 BP 64 EP 68 DI 10.1063/1.881365 PG 5 WC Physics, Multidisciplinary SC Physics GA ME882 UT WOS:A1993ME88200012 ER PT J AU HANSON, DK TIEDE, DM NANCE, SL CHANG, CH SCHIFFER, M AF HANSON, DK TIEDE, DM NANCE, SL CHANG, CH SCHIFFER, M TI SITE-SPECIFIC AND COMPENSATORY MUTATIONS IMPLY UNEXPECTED PATHWAYS FOR PROTON DELIVERY TO THE Q(B) BINDING-SITE OF THE PHOTOSYNTHETIC REACTION-CENTER SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE PROTON TRANSFER; PHOTOSYNTHESIS; SUPPRESSOR MUTATIONS; ELECTRON TRANSFER; MEMBRANE PROTEIN ID BACTERIAL REACTION CENTERS; AMINO-ACID SEQUENCE; RHODOBACTER-SPHAEROIDES; RHODOPSEUDOMONAS-VIRIDIS; ELECTRON-TRANSFER; L-SUBUNIT; CHLOROFLEXUS-AURANTIACUS; SECONDARY QUINONE; NUCLEOTIDE; CAPSULATA AB In photosynthetic reaction centers, a quinone molecule, Q(B), is the terminal acceptor in light-induced electron transfer. The protonatable residues Glu-L212 and Asp-L213 have been implicated in the binding of Q(B) and in proton transfer to Q(B) anions generated by electron transfer from the primary quinone Q(A). Here we report the details of the construction of the Ala-L212/Ala-L213 double mutant strain by site-specific mutagenesis and show that its photosynthetic incompetence is due to an inability to deliver protons to the Q(B) anions. We also report the isolation and biophysical characterization of a collection of revertant and suppressor strains that have regained the photosynthetic phenotype. The compensatory mutations that restore function are diverse and show that neither Glu-L212 nor Asp-L213 is essential for efficient light-induced electron or proton transfer in Rhodobacter capsulatus. Second-site mutations, located within the Q(B) binding pocket or at more distant sites, can compensate for mutations at L212 and L213 to restore photocompetence. Acquisition of a single negatively charged residue (at position L213, across the binding pocket at position L225, or outside the pocket at M43) or loss of a Positively charged residue (at position M231) is sufficient to restore proton transfer activity to the complex. The proton transport pathways in the suppressor strains cannot, in principle, be identical to that of the wild type. The apparent mutability of this pathway suggests that the reaction center can serve as a model system to study the structural basis of protein-mediated proton transport. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP HANSON, DK (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. FU NIGMS NIH HHS [GM36398] NR 42 TC 61 Z9 61 U1 0 U2 0 PU NATL ACAD SCIENCES 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 OCT 1 PY 1993 VL 90 IS 19 BP 8929 EP 8933 DI 10.1073/pnas.90.19.8929 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MA595 UT WOS:A1993MA59500037 PM 8105468 ER PT J AU NUNEZ, J LLACER, J AF NUNEZ, J LLACER, J TI A GENERAL BAYESIAN IMAGE-RECONSTRUCTION ALGORITHM WITH ENTROPY PRIOR - PRELIMINARY APPLICATION TO HST DATA SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID MAXIMUM-ENTROPY; EMISSION TOMOGRAPHY; FEASIBLE IMAGES; EM ALGORITHM; RESTORATION; LIKELIHOOD AB This paper describes a general Bayesian iterative algorithm with entropy prior for image reconstruction. It solves the cases of both pure Poisson data and Poisson data with Gaussian readout noise. The algorithm maintains positivity of the solution; it includes case-specific prior information (default map) and flatfield corrections; it removes background and can be accelerated to be faster than the Richardson-Lucy algorithm. In order to determine the hyperparameter that balances the entropy and likelihood terms in the Bayesian approach, we have used a likelihood cross-validation technique. Cross-validation is more robust than other methods because it is less demanding in terms of the knowledge of exact data characteristics and of the point-spread function. We have used the algorithm to reconstruct successfully images obtained in different space- and ground-based imaging situations. It has been possible to recover most of the original intended capabilities of the Hubble Space Telescope wide field and planetary camera and faint object camera from images obtained in their present state. Semireal simulations for the future wide field planetary camera 2 show that even after the repair of the spherical aberration problem, image reconstruction can play a key role in improving the resolution of the cameras, well beyond the design of the Hubble instruments. We also show that ground-based images can be reconstructed successfully with the algorithm. A technique which consists of dividing the CCD observations into two frames, with one-half the exposure time each, emerges as a recommended procedure for the utilization of the described algorithms. We have compared our technique with two commonly used reconstruction algorithms: the Richardson-Lucy and the Cambridge maximum entropy algorithms. C1 OBSERV FABRA,BARCELONA,SPAIN. LAWRENCE BERKELEY LAB,DIV ENGN,BERKELEY,CA 94720. RP NUNEZ, J (reprint author), UNIV BARCELONA,DEPT ASTRON & METEOROL,AV DIAGONAL 647,E-08028 BARCELONA,SPAIN. NR 29 TC 24 Z9 24 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD OCT PY 1993 VL 105 IS 692 BP 1192 EP 1208 DI 10.1086/133297 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MD190 UT WOS:A1993MD19000012 ER PT J AU JACOBSON, BS AF JACOBSON, BS TI OPTIMUM INACTIVATION DOSE AND INDEXES OF RADIATION RESPONSE BASED ON THE LINEAR-QUADRATIC SURVIVAL EQUATION SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article ID TUMOR-CELL-LINES; REPAIR MODEL; RADIOSENSITIVITY; CURVES AB For typical tumor-cell dose-response curves, the efficiency ratio, i.e., the ratio between the fraction of cells killed and the radiation dose administered, is a continuously decreasing function of dose. However, if the survival curve is sufficiently ''shouldered '', this ratio has a maximum value at a dose greater than zero. In radiotherapy, one possible criterion for the ideal dose per session is a high value of the efficiency ratio for the targeted cells, but a low value for surrounding healthy cells. Efficiency ratios can be derived from dose-response relationships. Any linear quadratic dose-survival curve of the form S = exp (-alphaD + betaD2) can be completely described by two parameters, s and phi, where s = alpha + square-root beta and phi = square-root beta/s. The former parameter is an index of radiosensitivitiy, and the latter is an index of curve shape. Using these indices, the ratio of fraction of inactivated cells to dose can be calculated and its maximum, as dose varies, determined. For values of phi greater than 0.55, this ratio has a maximum when the dose is approximately 1/s. However, for values of phi less than 0.4, this ratio is greatest when the dose is zero. Since phi varies widely among different cell lines, it may be possible to optimize radiotherapeutic dose-fractionation regimes using these indices. The parameterization of dose-survivial relationships in terms of s and phi also simplifies conceptualization of the survival-curve characteristics. Both the mean inactivation dose and the dose required to reduce survival to 1/e are approximately equal to 1/s. The fraction surviving a dose of 1/s falls between exp(-1) and exp(-3/4). This dose is approximately equal to the mean inactivation dose; for human tumor cells, its mean is approximately 2 Gy. The dose corresponding to a fraction surviving equal to 1/e, or ln(S) = -1, falls between 1/s and 5/4 s for all non-negative values of alpha and beta. RP JACOBSON, BS (reprint author), PACIFIC NW LAB, DEPT BIOL & CHEM P8-47, POB 999, RICHLAND, WA 99352 USA. NR 22 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD OCT PY 1993 VL 32 IS 4 BP 311 EP 317 DI 10.1007/BF01225918 PG 7 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA MH874 UT WOS:A1993MH87400005 PM 8310125 ER PT J AU MATTHEWS, SM BOEGEL, AJ LOFTIS, JA CAUFIELD, RA MINCHER, BJ MEIKRANTZ, DH MURPHY, RJ AF MATTHEWS, SM BOEGEL, AJ LOFTIS, JA CAUFIELD, RA MINCHER, BJ MEIKRANTZ, DH MURPHY, RJ TI DECOMPOSITION OF HALOGENATED HYDROCARBONS USING INTENSE, PENETRATING BREMSSTRAHLUNG SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL MEETING ON RADIATION PROCESSING CY SEP 13-18, 1992 CL BEIJING, PEOPLES R CHINA DE IONIZING RADIATION; BREMSSTRAHLUNG; ELECTRON BEAM; CHLORINATED HYDROCARBONS; SUPERFUND SITE; RADIOLYTIC DECOMPOSITION; VOC; TCE AB Radiolytic decomposition of chlorinated hydrocarbons and other toxic compounds has been experimentally measured using ionizing radiation produced by electron accelerator and nuclear isotope sources. Decomposition products have been identified. A portable, commercially available electron accelerator was set up at a Superfund site where vapor extraction wells were removing trichloroethylene (TCE) from a spill into the unsaturated soil. The extraction vapor was passed through the accelerator beam to decompose the TCE. On site radiolytic decomposition of TCE vapor using an accelerator is shown to be significantly less expensive than filtration of TCE vapor using activated charcoal. C1 IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. RP MATTHEWS, SM (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,MAIL CODE L629,LIVERMORE,CA 94550, USA. RI Mincher, Bruce/C-7758-2017 NR 1 TC 16 Z9 17 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0146-5724 J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT-DEC PY 1993 VL 42 IS 4-6 BP 689 EP 693 DI 10.1016/0969-806X(93)90353-V PG 5 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA LK325 UT WOS:A1993LK32500027 ER PT J AU FARRAR, H DERR, DD VEHAR, DW AF FARRAR, H DERR, DD VEHAR, DW TI ADVANCEMENTS IN INTERNATIONALLY ACCEPTED STANDARDS FOR RADIATION PROCESSING SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL MEETING ON RADIATION PROCESSING CY SEP 13-18, 1992 CL BEIJING, PEOPLES R CHINA DE ABSORBED DOSE; DOSE MEASUREMENT; DOSIMETRY; DOSIMETRY STANDARDS; FOOD IRRADIATION; FOOD PROCESSING; RADIATION HARDNESS TESTING; RADIATION PROCESSING AB Three subcommittees of the American Society for Testing and Materials (ASTM) are developing standards on various aspects of radiation processing. subcommittee E10.01 ''Dosimetry for Radiation Processing'' has published 9 standards on how to select and calibrate dosimeters, where to put them, how many to use, and how to use individual types of dosimeter systems. The group is also developing standards on how to use gamma, electron beam, and x-ray facilities for radiation processing, and a standard on how to treat dose uncertainties. Efforts are underway to promote inclusion of these standards into procedures now being developed by government agencies and by international groUps such as the United Nations' International Consultative Group on Food Irradiation (ICGFI) in order co harmonize regulations and help avoid trade barriers. Subcommittee F10.10 ''Food Processing and Packaging'' has completed standards on good irradiation practices for meat and poultry and for fresh fruits, and is developing similar standards for the irradiation of seafood and spices. These food-related standards are based on practices previously published by ICGFI. Subcommittee E10.07 on ''Radiation Dosimetry for Radiation Effects on Materials and Devices'' principally develops standards for determining doses for radiation hardness testing of electronics. Some, including their standards on the Fricke and TLD dosimetry systems are equally useful in other radiation processing applications. C1 USDA,ASTM SUBCOM F1010,WASHINGTON,DC 20250. SANDIA NATL LABS,ASTM SUBCOMM E1007,ALBUQUERQUE,NM 87185. RP FARRAR, H (reprint author), ASTM SUBCOMM E1001,18 FLINTLOCK LANE,BELL CANYON,CA 91307, USA. NR 0 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 0146-5724 J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT-DEC PY 1993 VL 42 IS 4-6 BP 853 EP 856 DI 10.1016/0969-806X(93)90388-B PG 4 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA LK325 UT WOS:A1993LK32500062 ER PT J AU TRIFUNAC, AD LOFFREDO, DM LIU, AD AF TRIFUNAC, AD LOFFREDO, DM LIU, AD TI EARLY EVENTS IN RADIATION-CHEMISTRY AND IN PHOTOIONIZATION SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL MEETING ON RADIATION PROCESSING CY SEP 13-18, 1992 CL BEIJING, PEOPLES R CHINA DE RADICAL CATIONS; ION-MOLECULE REACTIONS; PHOTOIONIZATION; RADIOLYSIS; FLASH PHOTOLYSIS; CONDUCTIVITY; PRODUCT STUDIES ID PULSE-RADIOLYSIS; FLUORESCENCE; CYCLOHEXANE; IONS; TIME AB Real-time studies of aliphatic and aromatic hydrocarbons by pulse radiolysis and laser photoionization reveal the chemistry of the ionic species in the condensed phase. The occurrence of radical cation reactions with solvent molecules provides the core mechanism capable of explaining a wide range of observations in photoionization and radiation chemistry. The study of products and transients in photoionization of aromatic solutes in hydrocarbon and alcohol solvents illustrates several details of this ''high-energy'' chemistry. A reaction pathway involving ion-molecule reaction of excited ions is indicated for a series of polycyclic aromatic hydrocarbons photoionized using intense excimer laser (248 and 308 nm) pulses in hydrocarbon and alcohol solutions. We have found that condensed-phase ion-molecule reactions in radiolysis are ubiquitous and we speculate on their overall role in hydrocarbon radiolysis. RP TRIFUNAC, AD (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 13 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0146-5724 J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT-DEC PY 1993 VL 42 IS 4-6 BP 967 EP 972 DI 10.1016/0969-806X(93)90414-P PG 6 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA LK325 UT WOS:A1993LK32500088 ER PT J AU SHAVERS, MR FRANKEL, K MILLER, J SCHIMMERLING, W TOWNSEND, LW WILSON, JW AF SHAVERS, MR FRANKEL, K MILLER, J SCHIMMERLING, W TOWNSEND, LW WILSON, JW TI THE FRAGMENTATION OF 670A MEV NE-20 AS A FUNCTION OF DEPTH IN WATER .3. ANALYTICAL MULTIGENERATION TRANSPORT-THEORY SO RADIATION RESEARCH LA English DT Article ID CROSS-SECTIONS; MEV NE-20; PROPAGATION; IONS C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. FU NCI NIH HHS [CA23247] NR 16 TC 16 Z9 16 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 1 EP 14 DI 10.2307/3578633 PG 14 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000001 PM 8210324 ER PT J AU EVANS, HH MENCL, J BAKALE, G RAO, PS JOSTES, RF HUI, TE CROSS, FT SCHWARTZ, JL AF EVANS, HH MENCL, J BAKALE, G RAO, PS JOSTES, RF HUI, TE CROSS, FT SCHWARTZ, JL TI INTERLABORATORY COMPARISON OF THE EFFECTS OF RADON ON L5178Y CELLS - DOSE CONTRIBUTION OF RADON DAUGHTER ASSOCIATION WITH CELLS SO RADIATION RESEARCH LA English DT Article ID ALPHA-PARTICLE; REPAIR; DOSIMETRY; APOPTOSIS; INVITRO C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. UNIV CHICAGO, CHICAGO, IL 60637 USA. RP EVANS, HH (reprint author), CASE WESTERN RESERVE UNIV, CLEVELAND, OH 44106 USA. FU NCI NIH HHS [P30 CA 43703] NR 16 TC 5 Z9 5 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 48 EP 56 DI 10.2307/3578639 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000007 PM 8210338 ER PT J AU EVANS, HH MENCL, J HUI, TE RICANATI, M HORNG, MF DISALVO, C BAKALE, G RAO, PS AF EVANS, HH MENCL, J HUI, TE RICANATI, M HORNG, MF DISALVO, C BAKALE, G RAO, PS TI CYTOTOXIC AND MUTAGENIC EFFECTS OF RADON AND RADON DAUGHTERS ON MURINE L5178Y LINES DIFFERING IN DNA-REPAIR SO RADIATION RESEARCH LA English DT Article ID DOUBLE-STRAND BREAKS; ACCELERATED HEAVY-IONS; MOUSE LYMPHOMA-CELLS; ALPHA-PARTICLES; MAMMALIAN-CELLS; IMPAIRED REPAIR; IONIZING-RADIATIONS; MULTILOCUS LESIONS; LOCUS MUTATIONS; GAMMA-RAYS C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP EVANS, HH (reprint author), CASE WESTERN RESERVE UNIV, CLEVELAND, OH 44106 USA. FU NCI NIH HHS [P30 CA 43703] NR 58 TC 15 Z9 15 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 57 EP 64 DI 10.2307/3578640 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000008 PM 8210339 ER PT J AU FORD, JR TERZAGHIHOWE, M AF FORD, JR TERZAGHIHOWE, M TI EFFECTS OF PO-210 ALPHA-PARTICLES ON SURVIVAL AND PRENEOPLASTIC TRANSFORMATION OF PRIMARY RAT TRACHEAL EPITHELIAL-CELLS IRRADIATED WHILE IN SUSPENSION OR IN THE INTACT TISSUE SO RADIATION RESEARCH LA English DT Article ID BASAL CELLS; INDUCTION; DAMAGE; RADON; KERATINOCYTES; RADIOBIOLOGY; POPULATIONS; FIBROBLASTS; DEPENDENCE; FREQUENCY RP FORD, JR (reprint author), OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN 37831, USA. NR 34 TC 23 Z9 23 U1 0 U2 3 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 89 EP 96 DI 10.2307/3578644 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000012 PM 8210343 ER PT J AU CARNES, BA FRITZ, TE AF CARNES, BA FRITZ, TE TI CONTINUOUS IRRADIATION OF BEAGLES WITH GAMMA-RAYS SO RADIATION RESEARCH LA English DT Article ID RADIATION CARCINOGENESIS RP CARNES, BA (reprint author), ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. FU NCI NIH HHS [YO1-CP-50503] NR 29 TC 16 Z9 16 U1 1 U2 2 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 103 EP 110 DI 10.2307/3578646 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000014 PM 8210325 ER PT J AU LANGLOIS, RG AKIYAMA, M KUSUNOKI, Y DUPONT, BR MOORE, DH BIGBEE, WL GRANT, SG JENSEN, RH AF LANGLOIS, RG AKIYAMA, M KUSUNOKI, Y DUPONT, BR MOORE, DH BIGBEE, WL GRANT, SG JENSEN, RH TI ANALYSIS OF SOMATIC-CELL MUTATIONS AT THE GLYCOPHORIN-A LOCUS IN ATOMIC-BOMB SURVIVORS - A COMPARATIVE-STUDY OF ASSAY-METHODS SO RADIATION RESEARCH LA English DT Article ID MUTANT FREQUENCY; RADIATION; ERYTHROCYTES; BIODOSIMETRY; MORTALITY; EXPOSURE; HUMANS C1 RADIAT EFFECTS RES FDN, DEPT RADIOBIOL, MINAMI KU, HIROSHIMA 732, JAPAN. RP LANGLOIS, RG (reprint author), LAWRENCE LIVERMORE NATL LAB, BIOL & BIOTECHNOL RES PROGRAM, L-452, LIVERMORE, CA 94550 USA. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 NR 21 TC 28 Z9 28 U1 0 U2 1 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 111 EP 117 DI 10.2307/3578647 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000015 PM 8210326 ER PT J AU GALAS, DJ AF GALAS, DJ TI IMPORTANT UNANSWERED QUESTIONS CONCERNING RADIATION RISK ESTIMATES SO RADIATION RESEARCH LA English DT Editorial Material C1 US DOE,WASHINGTON,DC 20585. RP GALAS, DJ (reprint author), DARWIN MOLEC CORP,KIRKLAND,WA, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1993 VL 136 IS 1 BP 139 EP 143 DI 10.2307/3578653 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA MD360 UT WOS:A1993MD36000020 PM 8210331 ER PT J AU BRUCE, JE ANDERSON, GA HOFSTADLER, SA VANORDEN, SL SHERMAN, MS ROCKWOOD, AL SMITH, RD AF BRUCE, JE ANDERSON, GA HOFSTADLER, SA VANORDEN, SL SHERMAN, MS ROCKWOOD, AL SMITH, RD TI SELECTED-ION ACCUMULATION FROM AN EXTERNAL ELECTROSPRAY-IONIZATION SOURCE WITH A FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETER SO RAPID COMMUNICATIONS IN MASS SPECTROMETRY LA English DT Article ID EXCITATION AB The coupling of an electrospray ionization (ESI) source to a Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer provides a facility for the high resolution, accurate mass analysis of large biopolymers. Typically the m/z range of the electrosprayed ions injected and trapped in the FTICR cell is between m/z 500 and 2500 (but can vary considerably with solution conditions). Recent reports on quadrupole excitation have demonstrated the ability to cool the magnetron motion of ions trapped in the FTICR mass spectrometer cell by converting this motion to cyclotron motion which, under appropriate pressure conditions, damps readily to the center of the cell. The use of a broadband waveform (swept frequency or stored waveform inverse Fourier-transform) for the quadrupole cooling pulse was shown to provide cooling of a wide range of m/z ions, while implementation of a single frequency demonstrated a much narrower m/z response. This report demonstrates the successful combination of single-frequency quadrupole cooling with external injection of electrosprayed ions into an FTICR mass spectrometer for m/z selected-ion accumulation. This capability is particularly significant with electrospray ionization since it allows ions of only one charge state to be accumulated in the cell, and greatly increases the potential dynamic range of ESI-FTICR. C1 PACIFIC NW LAB, DEPT CHEM SCI, CHEM METHODS & SEPARAT GRP, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 20 TC 63 Z9 63 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0951-4198 J9 RAPID COMMUN MASS SP JI Rapid Commun. Mass Spectrom. PD OCT PY 1993 VL 7 IS 10 BP 914 EP 919 DI 10.1002/rcm.1290071012 PG 6 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA MB717 UT WOS:A1993MB71700011 ER PT J AU TANG, K ALLMAN, SL CHEN, CH AF TANG, K ALLMAN, SL CHEN, CH TI MATRIX-ASSISTED LASER-DESORPTION IONIZATION OF OLIGONUCLEOTIDES WITH VARIOUS MATRICES SO RAPID COMMUNICATIONS IN MASS SPECTROMETRY LA English DT Article ID MASS-SPECTROMETRY; ABLATION; ACIDS AB Ferulic acid, 3-hydroxypicolinic acid (3-HPA), and 2,5-dihydroxybenzoic acid (2,5-DHB) were used as matrices in MALDI of various oligonucleotides. It was found that 2,5-DHB is an excellent matrix for polydeoxyribothymidylic acid. A poly-T oligonucleotide with a size of 130 bases was successfully detected. 3-HPA was found to be a good matrix for MALDI of homo-oligomeric deoxynucleotides as well as those containing four different bases. Parent ions of pd(A)60, d(T)100, d(G)40, and d(C)40 were observed, and a mixed-base oligonucleotide of 150-mer was also detected. Polymer ions of poly-A as large as 420-mer were measured; however, the efficiency for detecting poly-T with 3-HPA as a matrix was slightly worse than when 2,5-DHB was used. Comparisons of three matrices for various oligonucleotides is also presented. C1 OAK RIDGE NATL LAB,POB 2008,BLDG 5500,MS-6378,OAK RIDGE,TN 37831. RI Allman, Steve/A-9121-2011; Tang, Kai/A-2194-2011 OI Allman, Steve/0000-0001-6538-7048; NR 22 TC 54 Z9 55 U1 0 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0951-4198 J9 RAPID COMMUN MASS SP JI Rapid Commun. Mass Spectrom. PD OCT PY 1993 VL 7 IS 10 BP 943 EP 948 DI 10.1002/rcm.1290071016 PG 6 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA MB717 UT WOS:A1993MB71700015 PM 8219322 ER PT J AU KAMPERSCHROER, JH GRISHAM, LR NEWMAN, RA OCONNOR, TE STEVENSON, TN VONHALLE, A WILLIAMS, MD WRIGHT, KE AF KAMPERSCHROER, JH GRISHAM, LR NEWMAN, RA OCONNOR, TE STEVENSON, TN VONHALLE, A WILLIAMS, MD WRIGHT, KE TI LOW Z IMPURITY ION EXTRACTION FROM TOKAMAK FUSION TEST REACTOR ION SOURCES SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID BALMER ALPHA-EMISSION; NEUTRAL BEAM INJECTORS; COLLISIONS; H+ AB Tokamak Fusion Test Reactor (TFTR) deuterium neutral beams have been operated unintentionally with significant quantities of extracted water ions. Water has been observed with an optical multichannel analyzer. These leaks were thermally induced with the contamination level increasing linearly with pulse length. Up to 6% of the beam current was attributed to water ions, corresponding to an instantaneous value of 12% at the end of a 1.5 s pulse. A similar contamination is observed during initial operation of ion sources exposed to air. Operation of new ion sources typically produces a contamination level of approximately 2%, with cleanup to undetectable levels in 50-100 beam pulses. Approximately 90% of the water extracted from ion sources with water leaks was deuterated, implying that there is the potential for tritiated water production during TFTR's forthcoming DT operation. It is concluded that isotope exchange in the plasma generator takes place rapidly, most likely as the result of surface catalysis. The primary concern is with O implanted into beam absorbers recombining with tritium, and the subsequent retention of T2O on cryopanels. RP KAMPERSCHROER, JH (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 37 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 1993 VL 64 IS 10 BP 2729 EP 2736 DI 10.1063/1.1144411 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA MC137 UT WOS:A1993MC13700002 ER PT J AU REJ, DJ BARTSCH, RR DAVIS, HA FAEHL, RJ GREENLY, JB WAGANAAR, WJ AF REJ, DJ BARTSCH, RR DAVIS, HA FAEHL, RJ GREENLY, JB WAGANAAR, WJ TI MICROSECOND PULSE-WIDTH, INTENSE, LIGHT-ION BEAM ACCELERATOR SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID INERTIAL CONFINEMENT FUSION; ANODE PLASMA; DIODE; IRRADIATION; SURFACE AB A relatively long-pulse width (0.1-1 mus) intense ion beam accelerator has been built for materials processing applications. An applied B(r), magnetically insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2 MV, 300-kJ Marx generator. The diode is designed with the aid of multidimensional particle-in-cell simulations. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse shaping. The effect of a plasma opening switch on diode behavior is considered. C1 CORNELL UNIV,PLASMA STUDIES LAB,ITHACA,NY 14853. RP REJ, DJ (reprint author), LOS ALAMOS NATL LAB,DIV PHYS,MS-E526,LOS ALAMOS,NM 87545, USA. NR 31 TC 28 Z9 28 U1 0 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 OCT PY 1993 VL 64 IS 10 BP 2753 EP 2760 DI 10.1063/1.1144414 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA MC137 UT WOS:A1993MC13700005 ER PT J AU SCHIFERL, D SHARMA, SK COONEY, TF WANG, SY MOHANAN, K AF SCHIFERL, D SHARMA, SK COONEY, TF WANG, SY MOHANAN, K TI MULTICHANNEL RAMAN-SPECTROMETRY SYSTEM FOR WEAKLY SCATTERING MATERIALS AT SIMULTANEOUS HIGH-PRESSURES AND HIGH-TEMPERATURES SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID DIAMOND-ANVIL CELL; SM-YAG; VIBRATIONAL-MODES; CALIBRATION; RUBY; SPECTROSCOPY; FLUORESCENCE; FORSTERITE; NITROGEN; SPECTRA AB A Raman system is described which is suitable for rapid determination of Raman spectra of silicates and other weak Raman scatterers under simultaneous high-pressure and high-temperature conditions. Samples are pressurized with an argon pressure medium and Sm:YAG pressure standard in an Inconel 718 or rhenium Merrill-Bassett diamond-anvil cell that is externally heated in a vacuum oven equipped with quartz windows on either side. Raman spectra are excited and collected through the front window using almost-equal-to 160-degrees scattering geometry. A triple spectrometer in conjunction with a holographic notch filter, disperses the Raman scattered radiation onto a liquid-nitrogen-cooled CCD detector. Simultaneously measured Sm:YAG fluorescence spectra are collected through the rear window and routed via an optical fiber to a second multichannel spectrometer system equipped with a diode-array detector. The high sensitivity of the detectors and the simultaneous measurement technique enable detection of and compensation of pressure drifts occurring at high temperature. The performance of the system is demonstrated by measurement of the positions and linewidths of the high-frequency Raman modes of polycrystalline forsterite (alpha-Mg2SiO4) at temperatures up to 930 K at pressures of approximately 8 GPa and up to 842 K at pressures in the range 12-14 GPa. C1 UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS,HONOLULU,HI 96822. RP SCHIFERL, D (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 32 TC 8 Z9 8 U1 0 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 OCT PY 1993 VL 64 IS 10 BP 2821 EP 2827 DI 10.1063/1.1144368 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA MC137 UT WOS:A1993MC13700014 ER PT J AU EVANS, JW AF EVANS, JW TI RANDOM AND COOPERATIVE SEQUENTIAL ADSORPTION SO REVIEWS OF MODERN PHYSICS LA English DT Review ID ONE-DIMENSIONAL LATTICE; MONTE-CARLO SIMULATION; SQUARE CELLULAR STRUCTURES; SOLID-STATE REACTIONS; PERCOLATION-CLUSTER PERIMETERS; TEMPERATURE EPITAXIAL-GROWTH; KINETIC PHASE-TRANSITIONS; RANDOM PARKING PROBLEM; LOW-COVERAGE KINETICS; FIXED-SIZE PARTICLES AB Irreversible random sequential adsorption (RSA) on lattices, and continuum ''car parking'' analogues, have long received attention as models for reactions on polymer chains, chemisorption on single-crystal surfaces, adsorption in colloidal systems, and solid state transformations. Cooperative generalizations of these models (CSA) are sometimes more appropriate, and can exhibit richer kinetics and spatial structure, e.g., autocatalysis and clustering. The distribution of filled or transformed sites in RSA and CSA is not described by an equilibrium Gibbs measure. This is the case even for the saturation ''jammed'' state of models where the lattice or space cannot fill completely. However exact analysis is often possible in one dimension, and a variety of powerful analytic methods have been developed for higher dimensional models. Here we review the detailed understanding of asymptotic kinetics, spatial correlations, percolative structure, etc., which is emerging for these far-from-equilibrium processes. C1 IOWA STATE UNIV SCI & TECHNOL, DEPT MATH, AMES, IA 50011 USA. RP IOWA STATE UNIV SCI & TECHNOL, US DOE, AMES LAB, AMES, IA 50011 USA. NR 435 TC 714 Z9 721 U1 7 U2 86 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD OCT PY 1993 VL 65 IS 4 BP 1281 EP 1329 DI 10.1103/RevModPhys.65.1281 PG 49 WC Physics, Multidisciplinary SC Physics GA MM657 UT WOS:A1993MM65700005 ER PT J AU MOSKOWITZ, PD AF MOSKOWITZ, PD TI RISK ASSESSMENT LIBRARY SO RISK ANALYSIS LA English DT Article RP MOSKOWITZ, PD (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD OCT PY 1993 VL 13 IS 5 BP 573 EP 573 DI 10.1111/j.1539-6924.1993.tb00017.x PG 1 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA MH191 UT WOS:A1993MH19100016 ER PT J AU STASKO, S FTHENAKIS, VM AF STASKO, S FTHENAKIS, VM TI MMSOILS, VERSION 2.2 SO RISK ANALYSIS LA English DT Article C1 SUNY STONY BROOK,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,BIOMED & ENVIRONM ASSESSMENT GRP,UPTON,NY 11973. NR 4 TC 3 Z9 3 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD OCT PY 1993 VL 13 IS 5 BP 575 EP 579 DI 10.1111/j.1539-6924.1993.tb00018.x PG 5 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA MH191 UT WOS:A1993MH19100017 ER PT J AU WILBERT, KA AF WILBERT, KA TI FATAL TRADEOFFS - PUBLIC AND PRIVATE RESPONSIBILITIES FOR RISK - VISCUSI,WK SO RISK ANALYSIS LA English DT Book Review RP WILBERT, KA (reprint author), OAK RIDGE NATL LAB,CTR RISK MANAGEMENT,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD OCT PY 1993 VL 13 IS 5 BP 582 EP 583 PG 2 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA MH191 UT WOS:A1993MH19100021 ER PT J AU ANDERSON, RC ALLEN, EB ANDERSON, MR FRALISH, JS MILLER, RM NIERING, WA AF ANDERSON, RC ALLEN, EB ANDERSON, MR FRALISH, JS MILLER, RM NIERING, WA TI SCIENCE AND RESTORATION SO SCIENCE LA English DT Letter C1 UNIV CALIF RIVERSIDE,DEPT BOT & PLANT SCI,RIVERSIDE,CA 92521. ILLINOIS STATE UNIV,DEPT HLTH SCI,NORMAL,IL 61761. SO ILLINOIS UNIV,DEPT FORESTRY,CARBONDALE,IL 62901. ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. CONNECTICUT COLL,DEPT BOT,NEW LONDON,CT 06320. RP ANDERSON, RC (reprint author), ILLINOIS STATE UNIV,DEPT BIOL,NORMAL,IL 61761, USA. NR 4 TC 1 Z9 1 U1 1 U2 5 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD OCT 1 PY 1993 VL 262 IS 5130 BP 14 EP 15 DI 10.1126/science.262.5130.14 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LZ635 UT WOS:A1993LZ63500005 PM 17742945 ER PT J AU COLLINS, F GALAS, D AF COLLINS, F GALAS, D TI A NEW 5-YEAR PLAN FOR THE UNITED-STATES HUMAN GENOME PROJECT SO SCIENCE LA English DT Article C1 US DOE,OFF HLTH & ENVIRONM RES,WASHINGTON,DC 20585. RP COLLINS, F (reprint author), NIH,NATL CTR HUMAN GENOME RES,BETHESDA,MD 20892, USA. NR 3 TC 231 Z9 237 U1 0 U2 6 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD OCT 1 PY 1993 VL 262 IS 5130 BP 43 EP 46 DI 10.1126/science.8211127 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LZ635 UT WOS:A1993LZ63500021 PM 8211127 ER PT J AU HALSEY, TC MARTIN, JE AF HALSEY, TC MARTIN, JE TI ELECTRORHEOLOGICAL FLUIDS SO SCIENTIFIC AMERICAN LA English DT Article C1 SANDIA NATL LABS,TECH STAFF,ALBUQUERQUE,NM 87185. RP HALSEY, TC (reprint author), UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637, USA. NR 3 TC 20 Z9 22 U1 0 U2 6 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD OCT PY 1993 VL 269 IS 4 BP 58 EP 64 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX609 UT WOS:A1993LX60900011 ER PT J AU PEMBER, RB AF PEMBER, RB TI NUMERICAL-METHODS FOR HYPERBOLIC CONSERVATION-LAWS WITH STIFF RELAXATION .1. SPURIOUS SOLUTIONS SO SIAM JOURNAL ON APPLIED MATHEMATICS LA English DT Article DE HYPERBOLIC CONSERVATION LAWS WITH RELAXATION; STIFF SOURCE TERMS; FINITE DIFFERENCE METHODS; SPURIOUS SOLUTIONS ID GENERALIZED RIEMANN PROBLEM; REACTING SHOCK-WAVES; MODIFIED EQUATION; FLOWS; GAS AB The author considers the numerical solution of hyperbolic systems of conservation laws with relaxation using a shock-capturing finite difference scheme on a fixed, uniform spatial grid. It is conjectured that certain a priori criteria ensure that the numerical method does not produce spurious solutions as the relaxation time vanishes. One criterion is that the limits of vanishing relaxation time and vanishing viscosity commute for the viscous regularization of the hyperbolic system. A second criterion is that a certain ''subcharacteristic'' condition be satisfied by the hyperbolic system. This conjecture is supported with analytical and numerical results for a specific example, the solution of generalized Riemann problems of a model system of equations with a fractional step scheme in which Godunov's method is coupled with the backward Euler method. Similar ideas are applied to the numerical solution of stiff detonation problems. RP PEMBER, RB (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV COMP & MATH RES,L-316,POB 808,LIVERMORE,CA 94550, USA. NR 39 TC 63 Z9 64 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1399 J9 SIAM J APPL MATH JI SIAM J. Appl. Math. PD OCT PY 1993 VL 53 IS 5 BP 1293 EP 1330 DI 10.1137/0153062 PG 38 WC Mathematics, Applied SC Mathematics GA MB784 UT WOS:A1993MB78400005 ER PT J AU CABLE, JW WAKABAYASHI, N RADHAKRISHNA, P AF CABLE, JW WAKABAYASHI, N RADHAKRISHNA, P TI A NEUTRON STUDY OF THE MAGNETIC-STRUCTURE OF MN3SN SO SOLID STATE COMMUNICATIONS LA English DT Article ID SPIN STRUCTURE AB Neutron diffraction measurements were made to examine the magnetic structure of Mn3Sn in the modulated triangular phase in an attempt to elucidate the energy gap observed in the spin-wave spectrum. In contrast to previous investigations, we find two distinct moment modulations, both of which are commensurate with the lattice at low temperatures but which become incommensurate with increasing temperature. These are interpreted as two coexistent modulated phases in an inhomogeneous distribution. For the dominant modulated phase we observed a third harmonic with approximately 20% of the amplitude of the first harmonic. On the basis of this observation along with the presence of an energy gap, we conclude that this modulated phase is not a regular helix as it is generally described in the literature, but instead should be described as a severely distorted helix with multilayer blocks of moments tending toward alignment along the easy six-fold axes in the basal plane. C1 KEIO UNIV,DEPT PHYS,YOKOHAMA,KANAGAWA 223,JAPAN. JAWAHARLAL NEHRU CTR ADV SCI RES,INDIAN INST SCI CAMPUS,BANGALORE 560012,INDIA. RP CABLE, JW (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 10 TC 11 Z9 11 U1 3 U2 16 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 OCT PY 1993 VL 88 IS 2 BP 161 EP 166 DI 10.1016/0038-1098(93)90400-H PG 6 WC Physics, Condensed Matter SC Physics GA MD273 UT WOS:A1993MD27300015 ER PT J AU MUNDY, JN GIN, GL AF MUNDY, JN GIN, GL TI IONIC TRANSPORT IN MIXED SODIUM RUBIDIUM ALUMINOGERMANATE GLASS SO SOLID STATE IONICS LA English DT Article ID CESIUM SILICATE-GLASSES; ELECTRICAL-CONDUCTIVITY; SOLID ELECTROLYTES; TRACER DIFFUSION; THERMAL-EXPANSION; CATION DIFFUSION; ALKALI SILICATE; CONDUCTORS; MODEL; SPECTROSCOPY AB Ionic conductivity measurements have been made as a function of temperature and Na/Rb ratio on six series of x(Na, Rb)2O:yAl2O3: (1-x-y)GeO2 glasses where (1-x-y)=0.9, 0.8, and 0.7 and y/x=0.33 and 1.0. The three series with x greater-than-or-equal-to 0.15 exhibit the common characteristic of mixed alkali glasses; a maximum in the enthalpy for conductivity, H(m), for glasses with Na/(Na+ Rb) congruent-to 0.4. No maximum in H(m) was observed in glasses with x greater-than-or-equal-to 0.1. The pre-exponential factors for the conductivity are analyzed to obtain relative values of the physical correlation factor or percolation efficiency, f1. The relative values of f1 show a maximum at Na/(Na + Rb) congruent-to 0.5 for each of the glass series. An explanation for the mixed alkali effect is given in terms of the temperature dependence of f1. RP MUNDY, JN (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 63 TC 3 Z9 3 U1 0 U2 1 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 OCT PY 1993 VL 66 IS 1-2 BP 69 EP 83 DI 10.1016/0167-2738(93)90030-7 PG 15 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA MH544 UT WOS:A1993MH54400011 ER PT J AU RIZZARDI, M MOHR, MS MERRILL, DW SELVIN, S AF RIZZARDI, M MOHR, MS MERRILL, DW SELVIN, S TI INTERFACING UNITED-STATES CENSUS MAP FILES WITH STATISTICAL GRAPHICS SOFTWARE - APPLICATION AND USE IN EPIDEMIOLOGY SO STATISTICS IN MEDICINE LA English DT Article AB In 1990, the United States Bureau of the Census released detailed geographic map files known as TIGER/Line (Topologically Integrated Geographic Encoding and Referencing). The TIGER files, accessible through purchase or federal repository libraries, contain 24 billion characters of data describing various geographic features including coastlines, hydrography, transportation networks, political boundaries, etc. for the entire United States. Many of these physical features are of potential interest in epidemiological case studies. Unfortunately, the TIGER data base only provides raw alphanumeric data; no utility software, graphical or otherwise, is included. Recently, the S statistical software package has been extended to include a map display function. The map function augments S's high-level approach towards statistical analysis and graphical display of data. Coupling this statistical software with the map data base developed for U.S. Census data collection will facilitate epidemiological research. We discuss the technical background necessary to utilize the TIGER data base for mapping with S. Two types of S maps, segment-based and polygon-based, are discussed along with methods to construct them from TIGER data. Polygon-based maps are useful for displaying regional statistical data, such as disease rates or incidence at the census tract level. Segment-based maps are easier to assemble and are appropriate when the data are not regionalized. Census tract data of AIDS incidence in San Francisco and lung cancer case locations relative to petrochemical refinery sites in Contra Costa County are used to illustrate the methods and potential uses of interfacing the TIGER data base with S. C1 UNIV CALIF BERKELEY,SCH PUBL HLTH,BERKELEY,CA 94720. RP RIZZARDI, M (reprint author), LAWRENCE BERKELEY LAB,DIV INFORMAT & COMP SCI,BLDG 50B-3238,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 8 TC 5 Z9 5 U1 2 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0277-6715 J9 STAT MED JI Stat. Med. PD OCT PY 1993 VL 12 IS 19-20 BP 1953 EP 1964 DI 10.1002/sim.4780121919 PG 12 WC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Medicine, Research & Experimental; Statistics & Probability SC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Research & Experimental Medicine; Mathematics GA MC579 UT WOS:A1993MC57900018 PM 8272673 ER PT J AU FORSYTH, EB AF FORSYTH, EB TI SUPERCONDUCTING POWER TRANSMISSION-SYSTEMS - THE PAST AND POSSIBLY THE FUTURE SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Review ID PERFORMANCE; CABLES AB From the late 1960s until the mid 1980s many projects conducted research on superconducting power transmission systems. The culmination was the testing of a prototype system rated for 1000 MV A-a power level suitable for initial trials in a utility system. The specific design adopted for each development produced differing requirements for the conductor, dielectric insulation, cooling system and the cryogenic enclosure. Similar constraints apply to a design based on the use of high-T(c) superconductors. If superconducting systems are to become a commercial reality they must fill a technical niche in the overall power delivery system and be economically competitive with conventional equipment. A detailed cost estimate for an 800 MV A superconducting power transmission system indicates the priorities that must be given in a research and development programme so that the most expensive components can be developed to achieve lower costs and at the same time improve the operational performance. RP FORSYTH, EB (reprint author), BROOKHAVEN NATL LAB,LONG ISL,NY 11973, USA. NR 34 TC 15 Z9 15 U1 0 U2 2 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 OCT PY 1993 VL 6 IS 10 BP 699 EP 714 DI 10.1088/0953-2048/6/10/001 PG 16 WC Physics, Applied; Physics, Condensed Matter SC Physics GA MF204 UT WOS:A1993MF20400001 ER PT J AU SAUTET, P DUNPHY, J OGLETREE, DF SALMERON, M AF SAUTET, P DUNPHY, J OGLETREE, DF SALMERON, M TI THE ROLE OF ELECTRONIC INTERFERENCES IN DETERMINING THE APPEARANCE OF STM IMAGES - APPLICATION TO THE S(2X2)/RE(0001) SYSTEM SO SURFACE SCIENCE LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SURFACES; FORCE; ATOM AB The ESQC theoretical approach to calculate STM image contrast is applied to the case of S chemisorbed on the Re(0001) surface. The method explicitly includes the interference of various electron pathways between tip and surface atoms by exact calculation of a scattering matrix of electrons through the tunneling gap. We show that due to these electronic interferences, the image is sensitive both to the tip structure and S position over the surface. C1 LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94620. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. ECOLE NORMALE SUPER,CHIM THEOR LAB,F-69340 LYON 07,FRANCE. INST RECH CATALYSE,F-69626 VILLEURBANNE,FRANCE. RI Sautet, Philippe/G-3710-2014; Ogletree, D Frank/D-9833-2016 OI Sautet, Philippe/0000-0002-8444-3348; Ogletree, D Frank/0000-0002-8159-0182 NR 20 TC 32 Z9 32 U1 0 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 OCT 1 PY 1993 VL 295 IS 3 BP 347 EP 352 DI 10.1016/0039-6028(93)90282-O PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LZ228 UT WOS:A1993LZ22800013 ER PT J AU MERRY, WR JORDAN, RE PADOWITZ, DF HARRIS, CB AF MERRY, WR JORDAN, RE PADOWITZ, DF HARRIS, CB TI ELECTRONS AT METAL-INSULATOR INTERFACES .1. THE EFFECT OF XE MONOLAYERS ON THE IMAGE POTENTIAL STATES OF AG(111) SO SURFACE SCIENCE LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; SURFACE-STATES; INVERSE-PHOTOEMISSION; 2-PHOTON PHOTOEMISSION; PHOTOELECTRON-SPECTROSCOPY; BAND-STRUCTURE; RYDBERG STATES; 111 SURFACES; NOBLE-METALS; CU(111) AB To explore the properties of electrons at interfaces, image-potential states on metal surfaces with physisorbed overlayers are being examined. Using angle-resolved two-photon photoemission we have measured changes in the binding energy and dispersion of image states for a Xe monolayer on the Ag(111) surface. The binding energy of the n = 1 state shifts from its clean surface value of -0.76 +/- 0.02 eV to a value of -0.67 +/- 0.02 eV at monolayer coverage. Dispersion measurements show that the effective mass (m*) of the image potential state decreases from (1.35 +/- 0.10)m(e) to the free-electron value of (1.00 +/- 0.05)m(e). A model in which the only effect of the adsorbate is to change the work function of the metal approximates the binding energy shift, but fails to account for the effective mass. Finally, we suggest a model in which the unique electronic structure of the first adsorbate layer shifts the electron probability density outward from the surface. The dielectric screening expected within the layer thus becomes less significant. The coupling of the electron to the metal substrate is lessened and consequently the effective mass approaches that of a free electron. C1 LAWRENCE BERKELEY LAB, DIV CHEM SCI, BERKELEY, CA 94720 USA. RP MERRY, WR (reprint author), UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA. NR 58 TC 54 Z9 54 U1 2 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 OCT 1 PY 1993 VL 295 IS 3 BP 393 EP 401 DI 10.1016/0039-6028(93)90286-S PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LZ228 UT WOS:A1993LZ22800017 ER PT J AU SEIDEL, RW AF SEIDEL, RW TI THE ORIGINS OF SDI, 1944-1983 - BAUCOM,DR SO TECHNOLOGY AND CULTURE LA English DT Book Review RP SEIDEL, RW (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0040-165X J9 TECHNOL CULT JI Technol. Cult. PD OCT PY 1993 VL 34 IS 4 BP 973 EP 975 DI 10.2307/3106450 PG 3 WC History & Philosophy Of Science SC History & Philosophy of Science GA MV523 UT WOS:A1993MV52300040 ER PT J AU CUSHMAN, JH GINN, TR AF CUSHMAN, JH GINN, TR TI NONLOCAL DISPERSION IN MEDIA WITH CONTINUOUSLY EVOLVING SCALES OF HETEROGENEITY SO TRANSPORT IN POROUS MEDIA LA English DT Article DE NONLOCAL DISPERSION; LAGRANGIAN DYNAMICS; MEMORY FUNCTION; HETEROGENEOUS POROUS MEDIA; STATISTICAL MECHANICS ID POROUS-MEDIA AB General nonlocal diffusive and dispersive transport theories are derived from molecular hydrodynamics and associated theories of statistical mechanical correlation functions, using the memory function formalism and the projection operator method. Expansion approximations of a spatially and temporally nonlocal convective-dispersive equation are introduced to derive linearized inverse solutions for transport coefficients. The development is focused on deriving relations between the frequency- and wave-vector-dependent dispersion tensor and measurable quantities. The resulting theory is applicable to porous media of fractal character. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP CUSHMAN, JH (reprint author), PURDUE UNIV, 1150 LILLY HALL, W LAFAYETTE, IN 47907 USA. NR 12 TC 158 Z9 160 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-3913 J9 TRANSPORT POROUS MED JI Transp. Porous Media PD OCT PY 1993 VL 13 IS 1 BP 123 EP 138 DI 10.1007/BF00613273 PG 16 WC Engineering, Chemical SC Engineering GA ML823 UT WOS:A1993ML82300006 ER PT J AU TSCHAPLINSKI, TJ NORBY, RJ WULLSCHLEGER, SD AF TSCHAPLINSKI, TJ NORBY, RJ WULLSCHLEGER, SD TI RESPONSES OF LOBLOLLY-PINE SEEDLINGS TO ELEVATED CO2 AND FLUCTUATING WATER-SUPPLY SO TREE PHYSIOLOGY LA English DT Article DE AMINO ACIDS; OSMOTIC ADJUSTMENT; PINUS-TAEDA; SOLUBLE CARBOHYDRATES AB Osmotic adjustment of loblolly pine (Pinus taeda L.) seedlings to fluctuating water supply in elevated CO2 was investigated. Seedlings were grown in controlled-environment chambers in either 350 or 700 mul l-1 CO2 with weekly watering for four months, after which they were either watered weekly (well-watered treatment) or every two weeks (water-stress treatment) for 59 days. Osmotic adjustment was assessed by pressure-volume analysis of shoots and by analysis of soluble carbohydrates and free amino acids in roots during the last drying cycle. In well-watered seedlings, elevated CO2 increased the concentration of soluble sugars in roots by 68%. Water stress reduced the soluble sugar concentration in roots of seedling growing in ambient CO2 to 26% of that in roots of well-watered seedlings. Elevated CO2 mitigated the water stress-induced decrease in the concentration of soluble sugars in roots. However, this was probably due, in part, to carbohydrate loading during the first four months when all seedlings were grown in the presence of a high water supply, rather than to osmotic adjustment to water stress. Water stress caused a doubling in the concentration of free primary amino acids in roots, whereas elevated CO2 reduced primary amino acid and nitrogen concentrations to 32 and 74%, respectively, of those in roots of seedlings grown in ambient CO2. There was no indication of large-scale osmotic adjustment to water stress or that elevated CO2 enhanced osmotic adjustment in loblolly pine. RP TSCHAPLINSKI, TJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Wullschleger, Stan/B-8297-2012; Norby, Richard/C-1773-2012; OI Wullschleger, Stan/0000-0002-9869-0446; Norby, Richard/0000-0002-0238-9828; Tschaplinski, Timothy/0000-0002-9540-6622 NR 0 TC 61 Z9 64 U1 0 U2 6 PU HERON PUBLISHING PI VICTORIA PA BOX 5579 STATION B, VICTORIA BC V8R 6S4, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD OCT PY 1993 VL 13 IS 3 BP 283 EP 296 PG 14 WC Forestry SC Forestry GA MD624 UT WOS:A1993MD62400007 ER PT J AU BHATTACHARYA, RS RAI, AK MCCORMICK, AW ERDEMIR, A AF BHATTACHARYA, RS RAI, AK MCCORMICK, AW ERDEMIR, A TI HIGH-ENERGY (MEV) ION-BEAM MODIFICATIONS OF SPUTTERED MOS2 COATINGS ON CERAMICS SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT TRIBOLOGY CONF CY OCT 19-21, 1992 CL SAN DIEGO, CA SP AMER SOC MECH ENGINEERS, SOC TRIBOLOGISTS & LUBRICAT ENGINEERS DE MOS2; ION BEAM MIXING; SPUTTERING; FRICTION COEFFICIENT; WEAR LIFE; CERAMIC ID TRIBOLOGICAL PROPERTIES; FILMS; FRICTION AB DC magnetron sputtered-MoS2 films of thicknesses between 500angstrom and 7500angstrom were deposited on NaCl, Si, sapphire, Si3N4 and ZrO2 substrates, and were subsequently ion irradiated by a 5 x 10(15) cm-2 dose of 2MeV Ag+ ions. Transmission electron microscopy (TEM), Rutherford backscattering (RBS) and Auger Electron Spectroscopy (AES) were utilized to study the microstructural and compositional changes of the film due to irradiation. The friction coefficient and sliding life were determined by ball-on-disc tests under both inert and humid conditions. Both as-deposited and ion-irradiated films were found to be amorphous, having a stoichiometry of MoS1.8. A low friction coefficient in the range of 0.03 to 0.04 was measured for both as-deposited and ion irradiated films. However, the sliding life of Ag+ ion-irradiated film was found to increase ten fold to thousand-fold compared to as-sputtered films on all the ceramic surfaces studied The improvement in wear life was correlated with a significant improvement in adhesion of the film with the substrate and a small increase in the density of the ion irradiated film. C1 ARGONNE NATL LAB,TRIBOL SECT,ARGONNE,IL 60439. RP BHATTACHARYA, RS (reprint author), UES INC,DAYTON,OH 45432, USA. NR 13 TC 3 Z9 3 U1 0 U2 3 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD OCT PY 1993 VL 36 IS 4 BP 621 EP 626 DI 10.1080/10402009308983203 PG 6 WC Engineering, Mechanical SC Engineering GA MC169 UT WOS:A1993MC16900014 ER PT J AU SAMPSON, RN APPS, M BROWN, S COLE, CV DOWNING, J HEATH, LS OJIMA, DS SMITH, TM SOLOMON, AM WISNIEWSKI, J AF SAMPSON, RN APPS, M BROWN, S COLE, CV DOWNING, J HEATH, LS OJIMA, DS SMITH, TM SOLOMON, AM WISNIEWSKI, J TI WORKSHOP SUMMARY STATEMENT - TERRESTRIAL BIOSPHERIC CARBON FLUXES - QUANTIFICATION OF SINKS AND SOURCES OF CO2 SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON TERRESTRIAL BIOSPHERIC CARBON FLUXES : QUANTIFICATION OF SINKS AND SOURCES OF CO2 CY MAR 01-05, 1993 CL BAD HARZBURG, GERMANY SP US EPA, EDISON ELECT INST, USDA FOREST SERV, GERMAN FED ENVIRONM AGCY, UMWELTBUNDESAMT, MINIST HOUSING PHYS PLANNING & ENVIRONM NETHERLANDS, GERMAN MARSHALL FUND US AB Understanding the role of terrestrial ecosystems in the global carbon (C) cycle has become increasingly important as policymakers consider options to address the issues associated with global change, particularly climate change. Sound scientific theories are critical in predicting how these systems may respond in the future, both to climate change and human actions. In March 1993, 60 scientists from 13 nations gathered in Bad Harzburg, Germany, to develop a state-of-the-science assessment of the present and likely future C fluxes associated with the major components of the earth's terrestrial biosphere. In the process, particular emphasis was placed on the potential for improving C sinks and managing long-term C sequestration. The majority of the week's work was conducted in eight working groups which independently considered a particular biome or subject area. The working groups considered: the Global Carbon Cycle; Boreal Forests and Tundra; Temperate Forests; Tropical Forests; Grasslands, Savannas and Deserts; Land and Water Interface Zones; Agroecosystems; and Biomass Management. This paper presents a brief overview of their major conclusions and findings. In addition, Table 1 brings together the best estimates from each group as to the current magnitude and estimated future direction of changes in the terrestrial C fluxes. C1 FORESTRY CANADA, CTR NO FORESTRY, EDMONTON T6H 355, AB, CANADA. UNIV ILLINOIS, DEPT FORESTRY, URBANA, IL 61801 USA. COLORADO STATE UNIV, USDA ARS, NAT RESOURCE ECOL LAB, FT COLLINS, CO 80523 USA. MARINE SCI LAB, PACIFIC NW LAB, SEQUIM, WA 98362 USA. US FOREST SERV, NE FOREST EXPT STN, RADNOR, PA 19087 USA. UNIV VIRGINIA, DEPT ENVIRONM SCI, CHARLOTTESVILLE, VA 22903 USA. US EPA, ENVIRONM RES LAB, CORVALLIS, OR 97331 USA. WISNIEWSKI & ASSOCIATES INC, FALLS CHURCH, VA 22043 USA. RP SAMPSON, RN (reprint author), AMER FORESTS, 1516 P ST NW, WASHINGTON, DC 20005 USA. RI Ojima, Dennis/C-5272-2016 NR 8 TC 35 Z9 62 U1 0 U2 8 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 OCT PY 1993 VL 70 IS 1-4 BP 3 EP 15 DI 10.1007/BF01104985 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA LZ846 UT WOS:A1993LZ84600003 ER PT J AU DOWNING, JP MEYBECK, M ORR, JC TWILLEY, RR SCHARPENSEEL, HW AF DOWNING, JP MEYBECK, M ORR, JC TWILLEY, RR SCHARPENSEEL, HW TI LAND AND WATER INTERFACE ZONES SO WATER AIR AND SOIL POLLUTION LA English DT Article ID OCEANIC CO2 INCREASE; CARBON-DIOXIDE; ATMOSPHERIC CO2; BUDGET; SINKS; CONSTRAINTS; NITROGEN; IMPACT; SEA AB This paper reports analyses of C pools and fluxes in land-water interface zones completed at the International Workshop: Terrestrial Biospheric Carbon Fluxes; Quantification of Sinks and Sources Of CO2 (Bad Harzburg, Germany, March 1-5, 1993). The objective was to determine the role of these zones as global sinks of atmospheric CO2 as part of a larger effort to quantify global C sinks and sources in the past (ca. 1850), the present, and the foreseeable future (ca. 2050). Assuming the world population doubles by the year 2050, storage of atmospheric C in reservoirs will also double, as will river loads of atmospheric C and nutrients. It is estimated that C sinks in temperate and boreal wetlands have decreased by about 50%, from 0.2 to 0.1 Gt C yr-1, since 1850. The total decrease for wetlands may be considerably larger when tropical wetlands are taken into account, however, the area and C density of tropical wetlands are not well known at this time. Changes in cultivation practices and improved sampling of methaneogenesis have caused estimates of CH4 emissions from ricelands to drop substantially from 150 to 60 Tg yr-1. Even with doubled N and P loads, rivers are unlikely to fertilize more than about 20% of the new primary production in the coastal ocean. The source of C for this new production may not be the atmosphere, however, because the coastal ocean exchanges large quantities of DIC with the open ocean. Until the C fluxes from air-sea exchange Of CO2 and DIC are better quantified, the C-sink potential of the coastal ocean will remain a major uncertainty in the global C cycle. Analysis of model simulations of oceanic C uptake reconfirmed that the open ocean appears to take up about 2.0 Gt C yr-1 from the atmosphere and that model estimates are in better accord now, +/-0.5 Gt C yr-1, than ever before. Land use management must consider the unique C sinks in coastal and alluvial wetlands in order to minimize the future negative impacts of agriculture and urban development. Long-term monitoring will be essential to prove the success, or failure, of management practices to sustain wetlands in the future. Relative to the other systems examined at the workshop, the C-sink capacity of the ocean (excluding estuaries) is not likely to be measurably affected in the foreseeable future by the management scenarios considered at the workshop. C1 CNRS, GEOL APPL LAB, F-75257 PARIS 05, FRANCE. CENS, DMS, MODELISAT CLIMAT & ENVIRONNEMENT LAB, F-91191 GIF SUR YVETTE, FRANCE. UNIV SW LOUISIANA, DEPT BIOL, LAFAYETTE, LA 70504 USA. UNIV HAMBURG, INST BODENKUNDE, W-2000 HAMBURG 13, GERMANY. RP DOWNING, JP (reprint author), MARINE SCI LAB, PACIFIC NW LAB, 1529 W SEQUIM BAY RD, SEQUIM, WA 98382 USA. RI Orr, James/C-5221-2009; OI Orr, James/0000-0002-8707-7080 NR 49 TC 8 Z9 19 U1 2 U2 30 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 1993 VL 70 IS 1-4 BP 123 EP 137 DI 10.1007/BF01104992 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA LZ846 UT WOS:A1993LZ84600010 ER PT J AU SAMPSON, RN WRIGHT, LL WINJUM, JK KINSMAN, JD BENNEMAN, J KURSTEN, E SCURLOCK, JMO AF SAMPSON, RN WRIGHT, LL WINJUM, JK KINSMAN, JD BENNEMAN, J KURSTEN, E SCURLOCK, JMO TI BIOMASS MANAGEMENT AND ENERGY SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON TERRESTRIAL BIOSPHERIC CARBON FLUXES : QUANTIFICATION OF SINKS AND SOURCES OF CO2 CY MAR 01-05, 1993 CL BAD HARZBURG, GERMANY SP US EPA, EDISON ELECT INST, USDA FOREST SERV, GERMAN FED ENVIRONM AGCY, UMWELTBUNDESAMT, MINIST HOUSING PHYS PLANNING & ENVIRONM NETHERLANDS, GERMAN MARSHALL FUND US ID EMISSIONS; ETHANOL; FOREST; CARBON AB The impact of managing biomass specifically for the conservation or production of energy can become a significant factor in the global management of atmopsheric CO2 over the next century. This paper evaluates the global potential for: (1) conserving energy by using trees and wood for shading, shelterbelts, windbreaks, and construction material; and (2) increasing the use of biomass and improving its conversion efficiency for producing heat, electricity, and liquid biofuels. The potential reduction in CO2 emissions possible by the anticipated time of atmospheric CO2 doubling was estimated to be up to 50 x 10(6) t C yr-1 for energy conservation and as high as 4 x 10(9) t C yr-1 for energy production. Of the many opportunities, two stand out Through afforestation of degraded and deforested lands, biomass energy production offers the potential of 0.36 to 1.9 x 10(9) t C yr-1 emission reduction. Dedicated energy crops, which include short-rotation woody crops, herbaceous energy crops, halophytes, some annual crops, and oilseeds, offer the potential of 0.2 to 1.0 x 10(9) t C yr-1 emission reduction. Also addressed in the paper, but not quantified, were establishment of new forests, increasing the productivity of existing forests, or protecting forests to sequester C as an offset against CO2 emissions from burning fossil fuels or forest destruction. Also addressed are uncertainties, gaps in scientific knowledge about ecosystems and their management, and policy considerations at the international and national levels. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. US EPA,NATL COUNCIL AIR & STREAM IMPROVEMENT,ENVIRONM RES LAB,CORVALLIS,OR 97333. EDISON ELECT INST,WASHINGTON,DC 20004. PRIMA KLIMA,W-4000 DUSSELDORF 12,GERMANY. KINGS COLL LONDON,DIV BIOSPHERE SCI,LONDON W8 7AH,ENGLAND. RP SAMPSON, RN (reprint author), AMER FORESTS,1516 P ST NW,WASHINGTON,DC 20005, USA. NR 29 TC 34 Z9 34 U1 4 U2 8 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 OCT PY 1993 VL 70 IS 1-4 BP 139 EP 159 DI 10.1007/BF01104993 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA LZ846 UT WOS:A1993LZ84600011 ER PT J AU LUXMOORE, RJ WULLSCHLEGER, SD HANSON, PJ AF LUXMOORE, RJ WULLSCHLEGER, SD HANSON, PJ TI FOREST RESPONSES TO CO2 ENRICHMENT AND CLIMATE WARMING SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON TERRESTRIAL BIOSPHERIC CARBON FLUXES : QUANTIFICATION OF SINKS AND SOURCES OF CO2 CY MAR 01-05, 1993 CL BAD HARZBURG, GERMANY SP US EPA, EDISON ELECT INST, USDA FOREST SERV, GERMAN FED ENVIRONM AGCY, UMWELTBUNDESAMT, MINIST HOUSING PHYS PLANNING & ENVIRONM NETHERLANDS, GERMAN MARSHALL FUND US ID ATMOSPHERIC CARBON-DIOXIDE; SOIL-NITROGEN MINERALIZATION; ELEVATED CO2; INTERIOR ALASKA; GAS-EXCHANGE; ROOT-GROWTH; RESPIRATION; TEMPERATURE; SEEDLINGS; TREES AB Two of the major uncertainties in forecasting future terrestrial sources and SinkS Of CO2 are the CO2-enhanced growth response of forests and soil warming effects on net CO2 efflux from forests. Carbon dioxide enrichment of tree seedlings over time periods less than 1 yr has generally resulted in enhanced rates of photosynthesis, decreased respiration, and increased growth, with minor increases in leaf area and small changes in C allocation. Exposure of woody species to elevated CO2 over several years has shown that high rates of photosynthesis may be sustained, but net C accumulation may not necessarily increase if CO2 release from soil respiration increases. The impact of the 25% rise in atmospheric CO2 with industrialization has been examined in tree ring chronologies from a range of species and locations. In contrast to the seedling tree results, there is no convincing evidence for CO2-enhanced stem growth of mature trees during the last several decades. However, if mature trees show a preferential root growth response to CO2 enrichment, the gain in root mass for an oak-hickory forest in eastern Tennessee is estimated to be only 9% over the last 40 years. Root data bases are inadequate for detecting such an effect. A very small shift in ecosystem nutrients from soil to vegetation could support CO2-enhanced growth. Climate warming and the accompanying increase in mean soil temperature could have a greater effect than CO2 enrichment on terrestrial sources and sinks Of CO2. Soil respiration and N mineralization have been shown to increase with soil temperature. If plant growth increases with increased N availability, and more C is fixed in growth than is released by soil respiration, then a negative feedback on climate warming will occur. If warming results in a net increase in CO2 efflux from forests, then a positive feedback will follow. A 2 to 4-degrees-C increase in soil temperature could increase CO2 efflux from soil by 15 to 32% in eastern deciduous forests. Quantifying C budget responses of forests to future global change scenarios will be speculative until mature tree responses to CO2 enrichment and the effects of temperature on terrestrial sources and sinks of CO2 can be determined. RP LUXMOORE, RJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Hanson, Paul J./D-8069-2011; Wullschleger, Stan/B-8297-2012 OI Hanson, Paul J./0000-0001-7293-3561; Wullschleger, Stan/0000-0002-9869-0446 NR 72 TC 33 Z9 33 U1 2 U2 18 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 OCT PY 1993 VL 70 IS 1-4 BP 309 EP 323 DI 10.1007/BF01105004 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA LZ846 UT WOS:A1993LZ84600022 ER PT J AU WRIGHT, LL HUGHES, EE AF WRIGHT, LL HUGHES, EE TI UNITED-STATES CARBON OFFSET POTENTIAL USING BIOMASS ENERGY-SYSTEMS SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON TERRESTRIAL BIOSPHERIC CARBON FLUXES : QUANTIFICATION OF SINKS AND SOURCES OF CO2 CY MAR 01-05, 1993 CL BAD HARZBURG, GERMANY SP US EPA, EDISON ELECT INST, USDA FOREST SERV, GERMAN FED ENVIRONM AGCY, UMWELTBUNDESAMT, MINIST HOUSING PHYS PLANNING & ENVIRONM NETHERLANDS, GERMAN MARSHALL FUND US ID ROTATION AB A previous analysis had assumed that about 20% of 1990 U.S. C emissions could be avoided by the substitution of biomass energy technologies for fossil energy technologies at some point in the future. Short-rotation woody crop (SRWC) plantations were found to be the dedicated feedstock supply system (DFSS) offering the greatest C emission reduction potential. High efficiency biomass to electricity systems were found to be the conversion technology offering the greatest C emission reduction potential. This paper evaluates what would be required in terms of rate of technology implementation and time period to reach the 20% reduction goal. On the feedstock supply side, new plantings would have to installed at an average a rate of 1 x 10(6) ha yr-1 while average yields would have to increase by 1.5% annually over the 35-year period. Such yield increases have been observed for high value agricultural crops with large government research support. On the generation side, it requires immediate adoption of available technologies with a net efficiency of 33% or higher (such as the Whole Tree Energy(TM) technology), installation of approximately 5000 MWe of new capacity each year, and rapid development and deployment of much higher efficiency technologies to result in an average of 42% efficiency by 2030. If tbese technology changes could be achieved at a linear rate, U.S. C emission reduction could progress at a rate of about 0.6% yr-1 over the next 35 years. C1 ELECT POWER RES INST,HYDROELECT GENERAT & RENEWABLE FUELS PROGRAM,PALO ALTO,CA 94303. RP WRIGHT, LL (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 25 TC 17 Z9 17 U1 1 U2 3 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 OCT PY 1993 VL 70 IS 1-4 BP 483 EP 497 DI 10.1007/BF01105017 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA LZ846 UT WOS:A1993LZ84600035 ER PT J AU CUSHMAN, JH GINN, TR AF CUSHMAN, JH GINN, TR TI ON DISPERSION IN FRACTAL POROUS-MEDIA SO WATER RESOURCES RESEARCH LA English DT Article ID DIFFUSION AB Molecular hydrodynamics and the associated theories of statistical mechanical correlation functions are used to develop a spatially and temporally nonlocal convective-dispersive equation for transport in fractal porous media. A frequency and wave vector dependent dispersion tensor is developed from statistical mechanical principles. All results reduce to their classical Fickian counterparts under appropriate conditions. C1 PACIFIC NW LAB, DEPT GEOSCI, RICHLAND, WA 99352 USA. RP CUSHMAN, JH (reprint author), PURDUE UNIV, DEPT LIFE SCI, 1150 LILLY HALL LIFE SCI, W LAFAYETTE, IN 47907 USA. NR 14 TC 25 Z9 25 U1 0 U2 0 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 OCT PY 1993 VL 29 IS 10 BP 3513 EP 3515 DI 10.1029/93WR01709 PG 3 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA MA368 UT WOS:A1993MA36800018 ER PT J AU VIANCO, PT AF VIANCO, PT TI THE PRESENT TRIUMPHS AND FUTURE-PROBLEMS WITH WAVE SOLDERING SO WELDING JOURNAL LA English DT Article RP VIANCO, PT (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 SN 0043-2296 J9 WELD J JI Weld. J. PD OCT PY 1993 VL 72 IS 10 BP 39 EP 44 PG 6 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA MA365 UT WOS:A1993MA36500007 ER PT J AU BUSSMANNHOLDER, A GENZEL, L SIMON, A BISHOP, AR AF BUSSMANNHOLDER, A GENZEL, L SIMON, A BISHOP, AR TI GAP DISTRIBUTION AND MULTIGAP-COUPLING IN HIGH T(C)S SO ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER LA English DT Article ID HIGH-TC SUPERCONDUCTORS; ENERGY GAPS; YBA2CU3O7; SCATTERING AB Gap coupling interaction is a necessary consequence if a superconducting system has a gap distribution, as found for the high-T(c) oxocuprates, since the interaction has to result in a single critical temperature T(c). This paper shows with the help of BCS gap-coupling equations and values of gap distribution, including gap weights from experiments, that T(c) values as observed are easily achievable with reasonable diagonal and off-diagonal coupling coefficients. Of course our phenomenologically derived coupling coefficients have to be verified from purely theoretical grounds. Most importantly, it is found that the highest gap contributes dominantly to T(c) in spite of its low weight. Predictions for a point-contact tunneling spectroscopy are made. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. RP MAX PLANCK INST FESTKORPERFORSCH, HEISENBERGSTR 1, D-70569 STUTTGART, GERMANY. NR 29 TC 23 Z9 23 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0722-3277 J9 Z PHYS B CON MAT JI Z. Phys. B-Condens. Mat. PD OCT PY 1993 VL 92 IS 2 BP 149 EP 154 DI 10.1007/BF01312170 PG 6 WC Physics, Condensed Matter SC Physics GA LZ856 UT WOS:A1993LZ85600004 ER PT J AU KNOLL, DA MCHUGH, PR AF KNOLL, DA MCHUGH, PR TI A FULLY IMPLICIT DIRECT NEWTON METHOD FOR THE STEADY-STATE NAVIER-STOKES EQUATIONS SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE FULLY IMPLICIT; MODIFIED NEWTONS METHOD; NUMERICAL JACOBIAN; MESH SEQUENCING; NAVIER-STOKES ID DIFFERENCE AB Newton's method and banded Gaussian elimination can be a CPU efficient method for steady-state solutions to two-dimensional Navier-Stokes equations. In this paper we look at techniques that increase the radius of convergence of Newton's method, reduce the number of times the Jacobian must be factored, and simplify evaluation of the Jacobian. The driven cavity and natural convection problems are used as test problems, and finite volume discretization is employed. RP KNOLL, DA (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 20 TC 12 Z9 12 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD SEP 30 PY 1993 VL 17 IS 6 BP 449 EP 461 DI 10.1002/fld.1650170602 PG 13 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA LW726 UT WOS:A1993LW72600001 ER PT J AU GRESHO, PM GARTLING, DK TORCZYNSKI, JR CLIFFE, KA WINTERS, KH GARRATT, TJ SPENCE, A GOODRICH, JW AF GRESHO, PM GARTLING, DK TORCZYNSKI, JR CLIFFE, KA WINTERS, KH GARRATT, TJ SPENCE, A GOODRICH, JW TI IS THE STEADY VISCOUS INCOMPRESSIBLE 2-DIMENSIONAL FLOW OVER A BACKWARD-FACING STEP AT RE=800 STABLE SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE BACKWARD-FACING STEP; FLOW STABILITY; INCOMPRESSIBLE FLOW ID NAVIER-STOKES EQUATIONS; FINITE-ELEMENT METHOD; FLUID-DYNAMICS AB A detailed case study is made of one particular solution of the 2D incompressible Navier-Stokes equations. Careful mesh refinement studies were made using four different methods (and computer codes): (1) a high-order finite-element method solving the unsteady equations by time-marching; (2) a high-order finite-element method solving both the steady equations and the associated linear-stability problem; (3) a second-order finite difference method solving the unsteady equations in streamfunction form by time-marching; and (4) a spectral-element method solving the unsteady equations by time-marching. The unanimous conclusion is that the correct solution for flow over the backward-facing step at Re = 800 is steady-and it is stable, to both small and large perturbations. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. ASPENTEC UK LTD,CAMBRIDGE,ENGLAND. UNIV BATH,SCH MATH SCI,BATH BA2 7AY,AVON,ENGLAND. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP GRESHO, PM (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 44 TC 102 Z9 103 U1 0 U2 11 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD SEP 30 PY 1993 VL 17 IS 6 BP 501 EP 541 DI 10.1002/fld.1650170605 PG 41 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA LW726 UT WOS:A1993LW72600004 ER PT J AU JOHNSTON, HS MILLER, CE OH, BY PATTEN, KO SISK, WN AF JOHNSTON, HS MILLER, CE OH, BY PATTEN, KO SISK, WN TI INTERNAL ENERGY-DISTRIBUTIONS FROM NITROGEN-DIOXIDE FLUORESCENCE .1. CUMULATIVE SUM METHOD SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID EXCITATION AB This article describes a method of obtaining information about the internal energy (E) distribution of a fluorescing population of nitrogen dioxide, NO2*, from its dispersed spectrum between 400 and 840 nm. We show that two fluorescing populations of the same average energy but different energy spread give statistically significant differences in their observed cumulative sum spectra, although the differences are small. Broadly spread distributions of NO2* internal energy are produced by photolysis of RNO2 molecules and by collisional deactivation of monoenergetically excited NO2. The cumulative sum fluorescence spectrum from a broadly distributed internal energy population is represented as a weighted combination of monoenergetically excited cumulative sum fluorescence spectra. A cumulative sum spectrum utilizes all of the data, is positive and single valued, and smoothly, monotonically increases with decreasing observation energy. By differentiation of the cumulative sum spectrum, the original spectrum is recovered undistorted. Unlike a structured monoenergetic fluorescence spectrum, the cumulative sum is well approximated by a simple algebraic expression, I(E,X), where E is the internal energy of NO2* and X are the photon energies of the observed spectrum. LIF spectra of NO2, which are essentially collision-free by virtue of low pressure and short observation times, are observed at 22 excitation wavelengths between 400 and 673 nm, and these provide the two parameters of I(EX). A matrix equation relates the observed cumulative sum spectrum of such data to the internal energy distribution, D(E(i)), of the associated fluorescing NO2* ensemble. This equation is solved indirectly, representing D(E(i)) by trial functions whose parameters are iteratively optimized to the data via a nonlinear least-squares algorithm. From the shape of the derived distribution, we evaluate the average internal energy, the internal energy spread, and the skewness of the population of molecules that fluoresce. We find the method is 20 times less sensitive to spread than to average energy. We test the method against synthetic spectra including realistic amounts of noise, and at the 95% confidence level, the average energy is recovered better than 1%, the spread better than 20%, and the skewness within about a factor of 2. C1 LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP JOHNSTON, HS (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. NR 15 TC 10 Z9 10 U1 0 U2 2 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 SEP 30 PY 1993 VL 97 IS 39 BP 9890 EP 9903 DI 10.1021/j100141a004 PG 14 WC Chemistry, Physical SC Chemistry GA LZ663 UT WOS:A1993LZ66300004 ER PT J AU PATTEN, KO JOHNSTON, HS AF PATTEN, KO JOHNSTON, HS TI INTERNAL ENERGY-DISTRIBUTIONS FROM NITROGEN-DIOXIDE FLUORESCENCE .2. COLLISIONAL ENERGY-TRANSFER FROM EXCITED NITROGEN-DIOXIDE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID IR-MULTIPHOTON ABSORPTION; POLYATOMIC-MOLECULES; INFRARED FLUORESCENCE; UV ABSORPTION; NO2; DEACTIVATION; EXCITATION; AZULENE; POPULATIONS; IONIZATION AB We follow the collisional deactivation of laser-excited nitrogen dioxide through its dispersed fluorescence. The energy acceptor gases are NO2 at four excitation energies ranging from 18 828 to 24 989 cm-1 and five monatomic gases, four diatomic gases, and three polyatomic gases with 18 828-cm-1 excitation energy. The nominal products are the shapes of the internal energy distributions, which are obtained and plotted for several representative cases. From these distributions, the first three moments of the internal energy distributions are derived as a function of molecular collisions and tabulated as (i) the average internal energy, (ii) energy spread, and (iii) skewness. These quantities are plotted against c(M)t, the product of buffer gas concentration c(M) and delay time after laser excitation t(0.5-2 mus), which is a quantity proportional to number of collisions. The negative slope of average energy vs c(M)t is the macroscopic energy-transfer rate constant, k(E)(M). Average energies [E] for all NO2-buffered data taken at four excitation wavelengths are well represented by the single equation, fourth order in energy: d[E]/d(c(NO2)t) = -k4[E]4, where k4 = 8.06 X 10(-25) (CM3)energy molecule-1 cm3 s-1. Energy-transfer rates increase in the order monatomics, diatomics, and polyatomics. The energy-transfer rate constants are in reasonable agreement with most values reported in the literature. Second and third moments of the internal energy population of collisionally deactivated nitrogen dioxide are the novel products of this article and show interesting trends with the number of Lennard-Jones collisions. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 33 TC 11 Z9 11 U1 2 U2 3 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 SEP 30 PY 1993 VL 97 IS 39 BP 9904 EP 9915 DI 10.1021/j100141a005 PG 12 WC Chemistry, Physical SC Chemistry GA LZ663 UT WOS:A1993LZ66300005 ER PT J AU SISK, WN MILLER, CE JOHNSTON, HS AF SISK, WN MILLER, CE JOHNSTON, HS TI INTERNAL ENERGY-DISTRIBUTIONS FROM NITROGEN-DIOXIDE FLUORESCENCE .3. PHOTOLYSIS OF JET-COOLED N2O4 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID DINITROGEN TETROXIDE; SPECTRUM AB A supersonic jet of N2O4 is photolyzed at three wavelengths: 351, 248, and 193 nm. The resultant NO2 fluorescence is dispersed, the fluorescence spectrum is folded into a cumulative sum, and the internal energy distribution of almost nascent photolysis products is found by the method of article 1 of this series. The spread of these product internal energy distributions increases as the photolysis energy increases from 351 to 248 to 193 nm. The most probable internal energy increases between 351- and 248-nm photolysis, but at 193-nm photolysis it is about the same as, or somewhat lower than, that at 248 nm. This apparent anomaly is explained in terms of the electronic states of the products. The internal energy distribution derived from 351-nm data is examined by the method of prior distribution, and the photolysis products are found to be one NO2 molecule in the ground electronic state and the other in the B-2(1) electronic state with 3 or 4 quanta of bending vibration excitation. The internal energy distributions at 193 and 248 nm are combined with Kawasaki's time-of-flight translational energy distributions at 193 and 248 nm, and upon adding considerations of molecular orbitals the product states are assigned for photolysis at 193 and 248 nm. From these considerations, it is concluded that the most probable N2O4 photodissociation channels are as follows: N2O4 + hnu (lambda = 351 nm) --> NO2* (B B-2(1), v2 = 3-4) + NO2 (X 2A1), N2O4 + hnu (lambda = 193 nm) --> NO2* (B-2(2)) + NO2* (B-2(2)), and N2O4 + hnu (lambda = 248 nm) --> NO2* (B-2(1)) + NO2* (B-2(2)). C1 LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. NR 31 TC 22 Z9 22 U1 0 U2 2 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 SEP 30 PY 1993 VL 97 IS 39 BP 9916 EP 9923 DI 10.1021/j100141a006 PG 8 WC Chemistry, Physical SC Chemistry GA LZ663 UT WOS:A1993LZ66300006 ER PT J AU MILLER, CE JOHNSTON, HS AF MILLER, CE JOHNSTON, HS TI INTERNAL ENERGY-DISTRIBUTIONS FROM NITROGEN-DIOXIDE FLUORESCENCE .4. VARIABLE-WAVELENGTH PHOTODISSOCIATION OF CLNO2 AND HONO2 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID NITRIC-ACID; PHOTOCHEMISTRY; PHOTOLYSIS; KINETICS AB The cumulative sum spectroscopy method is used to derive internal energy distributions for the fluorescing NO2 ensembles from ClNO2 and HONO2 photodissociations as a function of the photolysis is wavelength. The fluorescing NO2 ensemble internal energy distribution, NO2* P(E(int)), for ClNO2 evolves from distributions peaked at 25 130 cm-1 to those having a majority of the NO2* components with internal energies less than 15 00 as the energy available to the photofragments decreases from 30 000 to 20 000 cm-1. The NO2* P(E(int)) distributions derived for HONO2 are dominated by components with energies less than 15 000 cm-1, and only for photolysis wavelengths shorter than 255 nm do the distributions have significant contributions from NO2* components approaching the maximum available energy. The PIF P(E(int)) derived from 308-nm ClNO2 photodissociation is compared to the P(E(T)) distribution derived from time-of-flight experiments, and the HONO2 PIF P(E(int)) distributions are compared to energy-partitioning measurements made after 241- and 280-nm photolysis. Examination of the ClNO2 and HONO2 absorption spectra in conjunction with the observed energy partitioning and theoretical calculations demonstrates that the R group perturbation on the local C2v symmetry of the NO2 chromophore determines that differences between CINO2 and HONO2 photolysis. C1 LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. NR 20 TC 14 Z9 14 U1 0 U2 0 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 SEP 30 PY 1993 VL 97 IS 39 BP 9924 EP 9933 DI 10.1021/j100141a007 PG 10 WC Chemistry, Physical SC Chemistry GA LZ663 UT WOS:A1993LZ66300007 ER PT J AU CUBITT, R FORGAN, EM YANG, G LEE, SL PAUL, DM MOOK, HA YETHIRAJ, M KES, PH LI, TW MENOVSKY, AA TARNAWSKI, Z MORTENSEN, K AF CUBITT, R FORGAN, EM YANG, G LEE, SL PAUL, DM MOOK, HA YETHIRAJ, M KES, PH LI, TW MENOVSKY, AA TARNAWSKI, Z MORTENSEN, K TI DIRECT OBSERVATION OF MAGNETIC-FLUX LATTICE MELTING AND DECOMPOSITION IN THE HIGH-T(C) SUPERCONDUCTOR BI2.15SR1.95CACU2O8+X SO NATURE LA English DT Article ID SINGLE-CRYSTAL YBA2CU3O7; HIGH-TC SUPERCONDUCTORS; NEUTRON-DIFFRACTION; THERMAL FLUCTUATIONS; II SUPERCONDUCTORS; PHASE-TRANSITIONS; LINE LATTICE; PENETRATION; CREEP; STATE AB The flux line lattice inside a single crystal of Bi2.15Sr1.95CaCu2O8+x has been observed using small-angle neutron diffraction. The diffracted intensity goes rapidly to zero at a magnetic-field-dependent flux lattice melting temperature; this melting coincides with the appearance of finite resistance within the superconducting state. The flux lattice signal can also be made to disappear at low temperatures, by applying a sufficiently high field, probably because of the decomposition of flux lines into two-dimensional 'pancake' vortices. C1 UNIV ZURICH,INST PHYS,CH-8057 ZURICH,SWITZERLAND. UNIV WARWICK,DEPT PHYS,COVENTRY CV4 7AL,W MIDLANDS,ENGLAND. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. LEIDEN UNIV,KAMERLINGH ONNES LAB,2312 AV LEIDEN,NETHERLANDS. UNIV AMSTERDAM,DEPT PHYS,1018 XE AMSTERDAM,NETHERLANDS. RISO NATL LAB,DEPT PHYS,DK-4000 ROSKILDE,DENMARK. RP CUBITT, R (reprint author), UNIV BIRMINGHAM,SCH PHYS & SPACE RES,EDGBASTON,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. RI cubitt, robert/B-9408-2008; Mortensen, Kell/A-5066-2009; Lee, Stephen/G-9791-2016 OI Mortensen, Kell/0000-0002-8998-9390; Lee, Stephen/0000-0002-2020-3310 NR 23 TC 385 Z9 385 U1 0 U2 19 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 30 PY 1993 VL 365 IS 6445 BP 407 EP 411 DI 10.1038/365407a0 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LZ633 UT WOS:A1993LZ63300046 ER PT J AU HALL, LJ RASIN, A AF HALL, LJ RASIN, A TI ON THE GENERALITY OF CERTAIN PREDICTIONS FOR QUARK MIXING SO PHYSICS LETTERS B LA English DT Article ID FERMION MASS MATRICES; CP-VIOLATION; ANSATZ; DECAYS; MODEL AB The relations \V(ub)\/\V(cb)\ = square-root m(u)/m(c) and \V(td)\/\V(ts)\ = square-root m(d)/m(s) are significant successes of some specific models for quark masses. We show that these relations are more general, resulting from a much wider class of models. Consequences of these predictions for CP violating asymmetries in neutral B meson decays are discussed. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP HALL, LJ (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 35 TC 95 Z9 95 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 SEP 30 PY 1993 VL 315 IS 1-2 BP 164 EP 169 DI 10.1016/0370-2693(93)90175-H PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LZ775 UT WOS:A1993LZ77500028 ER PT J AU FRABETTI, PL BOGART, CW CHEUNG, HWK CULY, S CUMALAT, JP JOHNS, WE BUTLER, JN DAVENPORT, F GAINES, I GARBINCIUS, PH GOURLAY, S HARDING, DJ KASPER, P KREYMER, A LEBRUN, P MENDEZ, H BIANCO, S ENORINI, M FABBRI, FL SPALLONE, A ZALLO, A CULBERTSON, R JAROSS, G LINGEL, K SHELDON, PD WILSON, JR WISS, J ALIMONTI, G ALLIATA, D BELLINI, G DICORATO, M GIAMMARCHI, M HAZAN, D INZANI, P LEVERARO, F MALVEZZI, S MENASCE, D MERONI, E MORONI, L PEDRINI, D PERASSO, L SALA, A SALA, S TORRETTA, D VITTONE, M BUCHHOLZ, D CASTOLDI, C GOBBI, B PARK, S YOSHIDA, R BISHOP, JM BUSENITZ, JK CASON, NM CUNNINGHAM, JD GARDNER, RW KENNEDY, CJ MANNEL, EJ MOUNTAIN, RJ PUSELJIC, DL RUCHTI, RC SHEPHARD, WD ZANABRIA, ME RATTI, SP VITULO, P LOPEZ, A AF FRABETTI, PL BOGART, CW CHEUNG, HWK CULY, S CUMALAT, JP JOHNS, WE BUTLER, JN DAVENPORT, F GAINES, I GARBINCIUS, PH GOURLAY, S HARDING, DJ KASPER, P KREYMER, A LEBRUN, P MENDEZ, H BIANCO, S ENORINI, M FABBRI, FL SPALLONE, A ZALLO, A CULBERTSON, R JAROSS, G LINGEL, K SHELDON, PD WILSON, JR WISS, J ALIMONTI, G ALLIATA, D BELLINI, G DICORATO, M GIAMMARCHI, M HAZAN, D INZANI, P LEVERARO, F MALVEZZI, S MENASCE, D MERONI, E MORONI, L PEDRINI, D PERASSO, L SALA, A SALA, S TORRETTA, D VITTONE, M BUCHHOLZ, D CASTOLDI, C GOBBI, B PARK, S YOSHIDA, R BISHOP, JM BUSENITZ, JK CASON, NM CUNNINGHAM, JD GARDNER, RW KENNEDY, CJ MANNEL, EJ MOUNTAIN, RJ PUSELJIC, DL RUCHTI, RC SHEPHARD, WD ZANABRIA, ME RATTI, SP VITULO, P LOPEZ, A TI STUDY OF D0-]K-MU+NU IN HIGH-ENERGY PHOTOPRODUCTION SO PHYSICS LETTERS B LA English DT Article ID BRANCHING FRACTIONS; RATIO AB We report a measurement of the semimuonic decay D0-->K-mu+nu from data taken during the 1987-1988 fixed target run at Fermilab by the E687 Collaboration. We obtain GAMMA(D0-->K-mu+nu)/GAMMA(D0-->K-pi+)=0.82+/-0.13+/-0.13 and use this result to calculate GAMMA(D0-->K*-mu+nu)/GAMMA(D0-->K-mu+nu)=0.59+/-0.10+/-0.13. C1 INFN,I-40126 BOLOGNA,ITALY. UNIV COLORADO,BOULDER,CO 80309. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. INFN,NAZL FRASCATI LAB,I-00044 FRASCATI,ITALY. UNIV ILLINOIS,URBANA,IL 61801. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. INFN,I-20133 MILAN,ITALY. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. UNIV PAVIA,DIPARTIMENTO FIS NUCL & TEOR,I-27100 PAVIA,ITALY. INFN,I-27100 PAVIA,ITALY. UNIV PUERTO RICO,MAYAGUEZ,PR 00708. RP FRABETTI, PL (reprint author), UNIV BOLOGNA,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. NR 14 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 30 PY 1993 VL 315 IS 1-2 BP 203 EP 208 DI 10.1016/0370-2693(93)90181-G PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LZ775 UT WOS:A1993LZ77500034 ER PT J AU WOO, LK HAYS, JA YOUNG, VG DAY, CL CARON, C DSOUZA, F KADISH, KM AF WOO, LK HAYS, JA YOUNG, VG DAY, CL CARON, C DSOUZA, F KADISH, KM TI SYNTHESIS, CHARACTERIZATION, SUBSTITUTION, AND ATOM-TRANSFER REACTIONS OF (ETA-2-ALKYNE)(TETRATOLYLPORPHYRINATO)TITANIUM(II) - X-RAY STRUCTURE OF TRANS-BIS(4-PICOLINE)(TETRATOLYLPORPHYRINATO)TITANIUM(II) SO INORGANIC CHEMISTRY LA English DT Article ID TITANIUM PORPHYRIN COMPLEXES; PEROXOTITANIUM(IV) PORPHYRINS; VANADIUM(IV) PORPHYRINS; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; DIOXYGEN ADDUCTS; ELECTRON-CAPTURE; AXIAL LIGANDS; REACTIVITY; DERIVATIVES AB A general preparative method for (tetratolylporphyrinato)titanium(II) eta2-acetylene complexes, (TTP)Ti(eta2-RC=CR'), (R = R' = CH3, CH2CH3, C6H5; R = CH3, R' = CH2CH3) is described. Displacement of 2-butyne from (TTP)Ti(eta2-MeC=CMe) with terminal acetylenes allows the preparation of (TTP)Ti(eta2-HC=CH) and (TTP)Ti(eta2-PhC=CH). The pi complexes undergo simple substitution reactions with pyridine (py) and 4-picoline (pic) to afford the bis(ligand) complexes trans-(TTP)Ti(PY)2 and trans-(TTP)Ti(PiC)2. The structure of the bis(picoline) complex, C66H56N4Ti, was determined by single-crystal X-ray diffraction (triclinic, P1BAR, a - 9.764(2) angstrom, b = 10.899(2) angstrom, c = 13.530(2) angstrom, alpha = 92.18(2)-degrees, beta = 98.10(2)-degrees, gamma = 114.14(2)-degrees, V = 1293.6(4) angstrom3, Z = 1, R = 5.2%, and R, = 5.4%). Crystallographic symmetry requires that the Ti atom resides in the center of the 24 atom porphyrin plane. The Ti-N(pic) distance is 2.223(3) angstrom, and the average Ti-N(pyrrole) distance is 2.047(8) angstrom. The two picoline ligands are coplanar, and the dihedral angle formed by the plane of the picoline rings and the Ti-N1 vector is 43. When (eta2-PhC=CPh)Ti(TTP) is treated with di-p-tolyldiazomethane, a diazo adduct (TTP)Ti=NN=C(C6H4CH3)2 is formed. Atom transfer occurs when (eta2-PhC=CPh)Ti(TTP) is treated with X=PPh3 (X = S, Se), resulting in a two-electron oxidized product, (TTP)Ti=X, PPh3, and free PhC=CPh. Treatment of (TTP)Ti(eta2-PhC=CPh) with elemental sulfur or selenium produces the perchalcogenido complexes (TTP)Ti(S2) and (TTP)Ti(Se2). The chalcogenide ligand complexes (TTP)Ti=S and (TTP)Ti=Se were also electrochemically characterized for comparison with related derivatives of (P)Ti(S2) and (P)Ti(Se2). Each compound undergoes two reversible one-electron reductions which are located at E1/2 = -1.07 +/- 0.01 and 1.47 +/- 0.01 V in CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate. They also undergo two oxidations, the first of which is irreversible, consistent with an electrode reaction involving the axial ligand rather than the porphyrin macrocycle. A comparison of potentials for oxidation of (TTP)Ti=X and (TPP)Ti(eta2-X2) indicates a stronger titanium-chalcogen bond in the case of the terminal selenide and sulfide derivatives as compared to the metal-chalcogen bond in the eta2-X2 complexes. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77004. RP WOO, LK (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 57 TC 34 Z9 34 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD SEP 29 PY 1993 VL 32 IS 20 BP 4186 EP 4192 DI 10.1021/ic00072a007 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LZ815 UT WOS:A1993LZ81500007 ER PT J AU SCHINDLER, S CASTNER, EW CREUTZ, C SUTIN, N AF SCHINDLER, S CASTNER, EW CREUTZ, C SUTIN, N TI REDUCTIVE QUENCHING OF THE EMISSION OF TRANS-DIOXO(1,4,8,11-TETRAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE)OSMIU M(VI) IN WATER SO INORGANIC CHEMISTRY LA English DT Article ID ELECTRON-TRANSFER REACTIONS; TRANSITION-METAL COMPLEXES; TERTIARY AMINE LIGANDS; EXCITED-STATE; CHARGE-TRANSFER; RATE CONSTANTS; OXO COMPLEXES; AMMINE COMPLEXES; CHLORINE DIOXIDE; OXIDATION AB Reductive quenching of the red emission of the metal-centered excited state of the title osmium(VI) complex (0.3 mM, lifetime 1.0 mus) has been characterized in water at 25-degrees-C (0.5 M ionic strength). The excited state is a very strong oxidant and is very rapidly quenched by a number of moderately reducing anions (anion, 10(-9)k(q), M-1 s-1): NO2-, 2.0; N3-, 4.0; I-, 6.5. The rate constants for quenching by aqua ions are in fair agreement with values calculated from the Marcus cross-relation and self-exchange rates for the *Os(VI)(tmc)O2(2+)/Os(V)(tmc)O2+ couple (k(ex) = 1 X 10(5) M-1 s-1) and the aqua ion couple (aqua ion, k(q)): Fe(H2O)62+, 1.0 X 10(9) M-1 s-1; Co(H2O)62+, 1.0 x 10(6) M-1 s-1; Ce(III)(aq), less-than-or-equal-to 1.0 X 10(5) M-1 s-1. The k(q) (M-1 s-1) values for quencher (Q) = Cl- (4 X 10(5)), HCO2- (1.5 X 10(6)), Br-(1.7 X 19(8)), SCN- (5.6 X 10(9)), CO32- (1.6 X 10(8)), and OH- (1.0 X 10(7)) are used to estimate self-exchange rate constants for the Q+/Q couples. The first estimates are presented for the CO32-/CO3- (0.4 M-1 s-1), OH./OH-(300 M-1 s-1), and HCO2/HCO2- (300 M-1 s-1) couples. Self-exchange rates for the X./X- halogen couples, calculated assuming that only the outer-shell barrier contributes to the intrinsic barrier to outer-sphere electron transfer and that a two-sphere dielectric continuum model is applicable, are orders of magnitude smaller than the self-exchange rates inferred from the quenching data and literature data. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RI Schindler, Siegfried/J-5045-2012 OI Schindler, Siegfried/0000-0002-9991-9513 NR 58 TC 34 Z9 35 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD SEP 29 PY 1993 VL 32 IS 20 BP 4200 EP 4208 DI 10.1021/ic00072a009 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LZ815 UT WOS:A1993LZ81500009 ER PT J AU HANKE, D WIEGHARDT, K NUBER, B LU, RS MCMULLAN, RK KOETZLE, TF BAU, R AF HANKE, D WIEGHARDT, K NUBER, B LU, RS MCMULLAN, RK KOETZLE, TF BAU, R TI SYNTHESIS AND X-RAY AND NEUTRON STRUCTURES OF ANTI-[L2RH2(H)2(MU-H)2](PF6)2 (L = 1,4,7-TRIMETHYL-1,4,7-TRIAZACYCLONONANE) AND A RELATED SPECIES CONTAINING A SYN-[RH2(H)2(MU-H)2]2+ CORE - ISOLATION OF [L2FE2(MU-H)3]BPH4 SO INORGANIC CHEMISTRY LA English DT Article ID CRYSTAL-STRUCTURE; HYDRIDE COMPLEXES; RHODIUM COMPLEX; LIGANDS; MEC(CH2PPH2)3; TRIDENTATE; CHEMISTRY; CATALYST; TRIPHOS; FAMILY AB The macrocyclic ligands 1,4,7-trimethyl-1,4,7-triazacyclononane (L) and 1,2-bis(4,7-dimethyl-1,4,7-triaza-1-cyclononyl)ethane (Me4dtne) react with RhCl3.3H2O in ethanol affording the neutral complexes LRhCl3 (1) and [(Me4dtne)Rh2Cl6]2H2O (2). Aqueous suspensions of 1 and 2 react with NaBH4 yielding upon addition of KPF6 red-brown crystals of air- and moisture-stable anti-[L2Rh2(H)2(mu-H)2](PF6)2 (3) and syn-[(Me4dtne)Rh2(H)2(mu-H)2](PF6)2 (4), respectively, LFeCl3 and Li[AH4] were found to form red [L2Fe2(mu-H)3]BPh4 (5) in tetrahydrofuran. The structure of 3 has been determined by single-crystal X-ray (295 K) and neutron diffraction (20 K). Neutron data for 3: monoclinic space group P2(1)/c, a = 8.155(l) angstrom, b = 11.768(2) angstrom, c = 15.611(2) angstrom, beta = 92.156(8)-degrees, V = 1497.1(2) angstrom3, Z = 2, D(calcd) = 1.869 g/cm3. The [HRh(mu-H)2RhH]2+ core contains a planar Rh2(mu-H)2 ring (Rh-H(b) = 1.754(2) angstrom; Rh ... Rh = 2.595(2) angstrom); each rhodium center has a terminal hydride ligand in anti-position with respect to each other (Rh-H(t) = 1.536(2) angstrom). The terminal hydride exerts a pronounced structural trans influence on the Rh-N bond in trans position (Rh-N(trans) = 2.276(1) angstrom vs average Rh-N(cis) = 2.082(1) angstrom. In 4 the [HRh(mu-H)2RhH]2+ core is syn configurated due to the steric requirements of the strapped macrocycle. The solution behavior of 3 and 4 has been studied by H-1 NMR spectroscopy. 3 is a fluctional molecule, and in contrast, 4 is rigid at ambient temperature. C1 RUHR UNIV BOCHUM,LEHRSTUHL ANORGAN CHEM 1,W-4630 BOCHUM,GERMANY. UNIV HEIDELBERG,INST ANORGAN CHEM,W-6900 HEIDELBERG,GERMANY. UNIV SO CALIF,DEPT CHEM,LOS ANGELES,CA 90089. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RI Wieghardt, Karl/B-4179-2014 NR 46 TC 41 Z9 41 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 SEP 29 PY 1993 VL 32 IS 20 BP 4300 EP 4305 DI 10.1021/ic00072a024 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LZ815 UT WOS:A1993LZ81500024 ER PT J AU GANGULI, AK GULOY, AM LEONESCAMILLA, EA CORBETT, JD AF GANGULI, AK GULOY, AM LEONESCAMILLA, EA CORBETT, JD TI CA31SN20 AND RELATED-COMPOUNDS - NOVEL ZINTL PHASES CONTAINING DIMERS AND PENTAMERS OF TIN OR LEAD SO INORGANIC CHEMISTRY LA English DT Article ID POLAR INTERMETALLIC COMPOUNDS; CHEMISTRY AB The phases Ca31Sn20, Sr31Pb20, and Yb31Pb20 are obtained by allowing the pure elements to react in sealed Ta containers at 1100-1180-degrees-C followed by slow cooling. All are isostructural with Pu31Pt20. The structure of Ca31Sn20 was redetermined (14/mcm, Z = 4, a = 12.5267(5) angstrom, c = 39.912(7) A, R/R(w) = 3.2%/3.7%). A new description of the structure is given in terms of isolated tin atoms plus well-bonded tin dimers and linear pentamers (d(Sn-Sn) = 3.06-3.16 angstrom) in proportions of 5:5:1 within a rather distorted W5Si3-like framework. Assignment of classical two-center bonds to the Sn-Sn interactions shows that the compound is electron-precise, consistent with Zintl-Klemm concepts for a valence compound. The diamagnetic susceptibilities of Ca31Sn20 and Sr31Pb20 and the semiconducting behavior of Ca31Sn20 are in accord with this description. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 29 TC 45 Z9 45 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD SEP 29 PY 1993 VL 32 IS 20 BP 4349 EP 4353 DI 10.1021/ic00072a031 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LZ815 UT WOS:A1993LZ81500031 ER PT J AU GANGULI, AK KWON, YU CORBETT, JD AF GANGULI, AK KWON, YU CORBETT, JD TI 3 NOVEL ZINTL PHASES IN THE MG-LA-SB SYSTEM BASED ON INTERGROWTH OF LASB AND MG3SB2 SLABS SO INORGANIC CHEMISTRY LA English DT Article ID POLAR INTERMETALLIC COMPOUNDS; CAAL2SI2 STRUCTURE; CHEMISTRY; OXIDES AB Reactions of the elements in welded Ta containers at 875-1050-degrees-C produce the black brittle compounds Mg4.5La4Sb7 (5-4-7), Mg4.6La3Sb6 (5-3-6), and Mg1.7La4.9Sb6 (2-5-6). All three consist of coherent intergrowths of Mg5Sb4 (in 5-4-7 and 5-3-6) or Mg2Sb2 (2-5-6) slabs derived froM Mg3Sb2 (3-0-2) (anti-alpha-La2O3) With La(n+1)Sb(n) slabs from LaSb (NaCl-type) for n = 3, 2, and 4, respectively, in which a layer of (111) La replaces octahedral (001) Mg at the interface. Crystal data for 5-4-7, 5-3-6, 2-5-6, 3-0-2, respectively, are as follows. Space group, Z: P3m1BAR, 1; R3mBAR, 3; R3mBAR, 3; P3m1BAR, 1. a = 4.6206(5), 4.615(1), 4.616(1), 4.559(1) angstrom; c = 26.069(7), 66.91(2), 67.67(4), 7.243(2) angstrom. No. of independent data, variables: 338, 29; 272, 26; 144, 20; 107, 10. R/R(w) (%): 3.0, 3.4; 2.4, 2.8; 2.2, 2.6; 1.5, 2.4. The refined deficiencies at Mg sites, and at the La interface in 2-5-6 as well, result from the above interfacial substitution and are in amounts necessary to afford valence (Zintl) compounds for all three. The 5-4-7, 2-5-6, and 3-0-2 compounds are diamagnetic and show temperature-independent resistivities of the order of 50, 85, and 530 muOMEGA-cm, respectively. Semi-metal behaviors are consistent with this property of bulk LaSb, the intergrowth structures, and Zintl phase concepts. Possibilities for the formation of analogous intergrowth compounds in other systems are suggested. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 32 TC 8 Z9 8 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 SEP 29 PY 1993 VL 32 IS 20 BP 4354 EP 4359 DI 10.1021/ic00072a032 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LZ815 UT WOS:A1993LZ81500032 ER PT J AU JAGUST, WJ EBERLING, JL ROBERTS, JA BRENNAN, KM HANRAHAN, SM VANBROCKLIN, H ENAS, JD BIEGON, A MATHIS, CA AF JAGUST, WJ EBERLING, JL ROBERTS, JA BRENNAN, KM HANRAHAN, SM VANBROCKLIN, H ENAS, JD BIEGON, A MATHIS, CA TI IN-VIVO IMAGING OF THE 5-HYDROXYTRYPTAMINE REUPTAKE SITE IN PRIMATE BRAIN USING SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY AND [I-123] 5-IODO-6-NITROQUIPAZINE SO EUROPEAN JOURNAL OF PHARMACOLOGY LA English DT Note DE SPECT (SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY); 5-HT (5-HYDROXYTRYPTAMINE, SEROTONIN); BRAIN (PRIMATE) ID HIGH-AFFINITY BINDING; H-3 6-NITROQUIPAZINE; RAT; IMIPRAMINE; PAROXETINE; INHIBITION; LIGAND AB Previous experiments have demonstrated that 5-iodo-6-nitro-2-piperazinylquinoline (5-I-6-NQP) is a potent and selective ligand for studying brain 5-hydroxytryptamine (5-HT) reuptake sites. We performed in vivo imaging in non-human primates using single photon emission computed tomography (SPECT) and the I-123-labeled compound [I-123]5-1-6-NQP. These studies showed rapid brain uptake, with slow egress of the tracer from the brainstem, a region rich in 5-HT reuptake sites. Loss of the tracer from regions with a lower density of these sites, such as cerebellum, was relatively more rapid. Pretreatment of animals with paroxetine increased the washout of tracer from the brainstem to rates similar to that seen in cerebellum. Brainstem to cerebellar ratios of tracer accumulation were > 2 by 8 h after injection, and in paroxetine pretreated animals remained close to 1. These results indicate that the radiotracer has characteristics suitable for use as a SPECT imaging agent of serotonin reuptake sites. C1 UNIV CALIF DAVIS,CALIF PRIMATE RES CTR,DAVIS,CA 95616. UNIV PITTSBURGH,DEPT RADIOL,PITTSBURGH,PA 15260. UNIV CALIF DAVIS,DEPT NEUROL,DAVIS,CA 95616. RP JAGUST, WJ (reprint author), LAWRENCE BERKELEY LAB,CTR FUNCT IMAGING,55-121,BERKELEY,CA 94720, USA. RI Mathis, Chester/A-8607-2009 FU NIA NIH HHS [AG07793, AG10129]; NINDS NIH HHS [NS22899] NR 13 TC 35 Z9 35 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-2999 J9 EUR J PHARMACOL JI Eur. J. Pharmacol. PD SEP 28 PY 1993 VL 242 IS 2 BP 189 EP 193 DI 10.1016/0014-2999(93)90079-W PG 5 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA MA408 UT WOS:A1993MA40800010 PM 8253114 ER PT J AU REINHOLD, CO BURGDORFER, J AF REINHOLD, CO BURGDORFER, J TI THE CLASSICAL LIMIT OF IONIZATION IN FAST ION-ATOM COLLISIONS SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; PHASE-SPACE DISTRIBUTIONS; EJECTED-ELECTRON SPECTRA; CHARGED-PARTICLES; INTERMEDIATE ENERGIES; ANGULAR-DISTRIBUTION; HYDROGEN COLLISIONS; STRIPPED IONS; FAST PROTONS; CAPTURE AB We study the classical-quantum correspondence for ionization in three-body fast ion-atom collisions. The existence of a classical limit of the quantum mechanical transition probabilities as a function of the momentum transferred to the electron during the collision, the impact parameter, the energy and angle of the emitted electron, and the initial quantum level of the target is investigated. A well behaved classical limit is shown to exist for large momentum transfers whereas ionization by small momentum transfers or at large impact parameters is shown to be classically suppressed. It is found that ionization at small impact parameters does not possess a well-defined classical limit. Modifications of classical trajectory Monte Carlo (CTMC) methods to account for non-classical ionization are suggested. Applications related to recent data for electron ejection into large angles are presented C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP REINHOLD, CO (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. OI Reinhold, Carlos/0000-0003-0100-4962 NR 53 TC 68 Z9 68 U1 0 U2 0 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 SEP 28 PY 1993 VL 26 IS 18 BP 3101 EP 3122 DI 10.1088/0953-4075/26/18/018 PG 22 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MA899 UT WOS:A1993MA89900018 ER PT J AU DILLON, MA BOESTEN, L TANAKA, H KIMURA, M SATO, H AF DILLON, MA BOESTEN, L TANAKA, H KIMURA, M SATO, H TI ELASTIC AND VIBRATIONALLY INELASTIC CROSS-SECTIONS AND ENERGY-LOSS SPECTRA FOR ELECTRON COLLISIONS WITH GEH4 SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID VAPOR-DEPOSITION; SCATTERING; SILANE; GERMANE; IMPACT; PHOTOIONIZATION; SPECTROSCOPY; EXCITATION; ETHANE; DCS AB Absolute vibrationally elastic cross sections for e-GeH4 collisions have been determined for electrons of 1, 2, 2.5, 3, 5, 7.5, 10, 15, 20, 60 and 100 eV incidence energy over a scattering angular range of 10-degrees-130-degrees. The observed angular distributions correspond, at least qualitatively, to theoretical formulations using the continuum-multiple-scattering method, the parameter-free static-exchange-polarizaton approximation, and a multichannel Schwinger variational calculation. Vibrational excitation functions and the energy distribution of elastically scattered electrons reveal a shape resonance at about 2-2.5 eV. Calculations show that the resonance scattering state belongs to the t2 representation of the T(d) point group, which is also the representation of the lowest unoccupied molecular orbital (LUMO) of GeH4. Energy loss spectra recorded in the electronic threshold region of GeH4 reveal enhanced inelastic scattering at large angles in the loss range 7-9 eV characteristic of excitation to the lowest triplet state. RP DILLON, MA (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 31 TC 24 Z9 24 U1 0 U2 1 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 SEP 28 PY 1993 VL 26 IS 18 BP 3147 EP 3158 DI 10.1088/0953-4075/26/18/021 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MA899 UT WOS:A1993MA89900021 ER PT J AU UEDA, K WEST, JB HAYES, MA SIGGEL, MRF PARR, AC DEHMER, JL AF UEDA, K WEST, JB HAYES, MA SIGGEL, MRF PARR, AC DEHMER, JL TI PHOTOELECTRON STUDY OF ELECTRONIC AUTOIONIZATION IN ROTATIONALLY COOLED N-2 - THE N=6 MEMBER OF THE HOPFIELD SERIES SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID ANGULAR-DISTRIBUTIONS; SYNCHROTRON RADIATION; BRANCHING RATIOS; RYDBERG SERIES; N2; PHOTOIONIZATION; THRESHOLD; SPECTRUM AB We report preliminary results of a study of the Hopfield series in rotationally cooled molecular nitrogen. By using angle resolved electron spectroscopy in combination with synchrotron radiation, partial cross sections and asymmetry parameters for formation of the vibrationally resolved X and A states of N2+ were measured in the region of the n = 6 member of the Hopfield bands. The results are compared with earlier ab initio MQDT calculations and reflect qualitative agreement for the X 2SIGMA(g)+ decay channel, but sharp disagreement for the A 2PI(u) decay channel. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. ARGONNE NATL LAB,ARGONNE,IL 60439. RP UEDA, K (reprint author), SERC,DARESBURY LAB,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. NR 20 TC 5 Z9 5 U1 0 U2 0 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 SEP 28 PY 1993 VL 26 IS 18 BP L601 EP L606 DI 10.1088/0953-4075/26/18/005 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA MA899 UT WOS:A1993MA89900005 ER PT J AU FRIEDMAN, DJ ZHU, JG KIBBLER, AE OLSON, JM MORELAND, J AF FRIEDMAN, DJ ZHU, JG KIBBLER, AE OLSON, JM MORELAND, J TI SURFACE-TOPOGRAPHY AND ORDERING-VARIANT SEGREGATION IN GALNP2 SO APPLIED PHYSICS LETTERS LA English DT Article ID ALLOY SEMICONDUCTORS; GROWTH-RATE; GAXIN1-XP; GAINP; GA0.5IN0.5P; PHASE AB Using transmission electron diffraction dark-field imaging, atomic force microscopy (AFM), and Nomarski microscopy, we demonstrate a direct connection between surface topography and cation site ordering in GaInP2. We study epilayers grown by organometallic vapor-phase epitaxy on GaAs substrates oriented 2-degrees off ( 100) towards (110). Nomarski microscopy shows that, as growth proceeds, the surface of ordered material forms faceted structures aligned roughly along [011]. A comparison with the dark-field demonstrates that the [111BAR] and [111BAR] ordering variants are segregated into complementary regions corresponding to opposite-facing facets of the surface structures. This observation cannot be rationalized with the obvious but naive model of the surface topography as being due to faceting into low-index planes. However, AFM reveals that the facets are in fact not low-index planes, but rather are tilted 4-degrees from (100) towards (111) B. This observation explains the segregation of the variants: the surface facets act as local (111) B-misoriented growth surfaces which select only one of the two variants. C1 NATL INST STAND & TECHNOL, BOULDER, CO 80303 USA. RP NATL RENEWABLE ENERGY LAB, 1617 COLE BLVD, GOLDEN, CO 80401 USA. NR 22 TC 33 Z9 34 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 27 PY 1993 VL 63 IS 13 BP 1774 EP 1776 DI 10.1063/1.110658 PG 3 WC Physics, Applied SC Physics GA LZ654 UT WOS:A1993LZ65400021 ER PT J AU CONTRERAS, M TUTTLE, J DU, DH QI, Y SWARTZLANDER, A TENNANT, A NOUFI, R AF CONTRERAS, M TUTTLE, J DU, DH QI, Y SWARTZLANDER, A TENNANT, A NOUFI, R TI GRADED BAND-GAP CU(IN,GA)SE2 THIN-FILM SOLAR-CELL ABSORBER WITH ENHANCED OPEN-CIRCUIT VOLTAGE SO APPLIED PHYSICS LETTERS LA English DT Article AB An important development in polycrystalline Cu(In,Ga)Se2 (CIGS) thin-film photovoltaic solar cells is the attainment of a high voltage device simultaneous with state-of-the-art conversion efficiency. This letter describes a CIGS-based solar cell that demonstrates an open-circuit voltage ( V(oc)) approaching 700 mV and a total-area conversion efficiency of 12.2%. The high value of V(oc) was achieved by grading In/Ga through the absorber by a computer-controlled physical vapor deposition (PVD) process that utilizes variable metal fluxes. RP NATL RENEWABLE ENERGY LAB, 1617 COLE BLVD, GOLDEN, CO 80401 USA. NR 7 TC 17 Z9 17 U1 0 U2 26 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 27 PY 1993 VL 63 IS 13 BP 1824 EP 1826 DI 10.1063/1.110675 PG 3 WC Physics, Applied SC Physics GA LZ654 UT WOS:A1993LZ65400038 ER PT J AU RENO, JL CHADDA, S MALLOY, K AF RENO, JL CHADDA, S MALLOY, K TI DISLOCATION DENSITY REDUCTION IN CDZNTE(100) ON GAAS USING STRAINED-LAYER SUPERLATTICES SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; CD1-XZNXTE; GROWTH; CDTE AB We have inserted Cd0.91Zn0.09Te/CdTe(100) strained layer superlattices of various periods into Cd0.955Zn0.045Te grown on GaAs(100). X-ray diffraction was used as a means to optimize the period of the strained layer superlattice to maximize the quality of the material. Transmission electron microscopy demonstrated that a dramatic decrease (a total of five orders of magnitude) in the dislocation density occurred due to the insertion of the strained layer superlattices. The dislocation density achieved is in a range usable as a substrate material for HgCdTe infrared detectors. C1 UNIV NEW MEXICO,CTR HIGH TECHNOL MAT,ALBUQUERQUE,NM 87131. RP RENO, JL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI Malloy, Kevin/E-5994-2010 NR 12 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 27 PY 1993 VL 63 IS 13 BP 1827 EP 1829 DI 10.1063/1.110676 PG 3 WC Physics, Applied SC Physics GA LZ654 UT WOS:A1993LZ65400039 ER PT J AU FOLTYN, SR TIWARI, P DYE, RC LE, MQ WU, XD AF FOLTYN, SR TIWARI, P DYE, RC LE, MQ WU, XD TI PULSED-LASER DEPOSITION OF THICK YBA2CU3O7-DELTA FILMS WITH JC-GREATER-THAN-1 MA/CM2 SO APPLIED PHYSICS LETTERS LA English DT Article ID CRITICAL CURRENT-DENSITY; BUFFER LAYERS; GROWTH; ORIENTATION; DEPENDENCE; LAALO3 AB Using pulsed laser deposition, YBa2Cu3O7-delta (YBCO) films ranging in thickness from 0.065 to 6.4 mum have been deposited on yttria-stabilized zirconia substrates with an intermediate layer of CeO2. The thinnest films have critical current densities of over 5 MA/cm2 at 75 K with zero applied field; as film thickness is increased, J(c) decreases asymptotically to 1 MA/cm2. X-ray analysis of a 2.2-mum-thick film shows that the YBCO is predominantly c-axis oriented and textured in-plane, while a Rutherford backscattering spectrometry minimum channeling yield of almost-equal-to 75% indicates that the film contains disordered material at this thickness. RP FOLTYN, SR (reprint author), LOS ALAMOS NATL LAB,CTR SUPERCONDUCTIV TECHNOL,LOS ALAMOS,NM 87545, USA. NR 24 TC 128 Z9 129 U1 0 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 SEP 27 PY 1993 VL 63 IS 13 BP 1848 EP 1850 DI 10.1063/1.110653 PG 3 WC Physics, Applied SC Physics GA LZ654 UT WOS:A1993LZ65400046 ER PT J AU CHEUNG, YW STEIN, RS WIGNALL, GD YANG, HE AF CHEUNG, YW STEIN, RS WIGNALL, GD YANG, HE TI SMALL-ANGLE SCATTERING INVESTIGATIONS OF POLY(EPSILON-CAPROLACTONE) POLYCARBONATE BLENDS .1. SMALL-ANGLE NEUTRON AND X-RAY-SCATTERING STUDY OF CRYSTALLINE BLEND MORPHOLOGY SO MACROMOLECULES LA English DT Article ID LIGHT-SCATTERING; POLYMER BLENDS; SYSTEM AB Crystalline morphologies of poly(epsilon-caprolactone) (PCL) and deuterated polycarbonate (d-PC) blends were studied by small-angle neutron and X-ray scattering (SANS and SAXS). Measurements were conducted at both room temperature and temperatures above the melting point (60-degrees-C) of PCL. Due to the different contrast between the phases for neutrons and X-rays, SANS exhibited a monotonic drop in intensity with increasing scattering angle while SAXS showed lamellar (peak) scattering. A two-correlation length model provided an excellent fit for the SANS data over the entire composition range. This model reproduced not only the shape but also the absolute magnitude of the scattering curves. The long range correlation length (approximately 10(2) angstrom) and the short range correlation length (approximately 10 angstrom) derived from this model are inferred to be associated with the crystalline PC domain and the local cluster in the amorphous phase (possibly resulting from crystallization-induced phase separation), respectively. Both the long range correlation length obtained from SANS and the long period measured from SAXS showed identical composition dependence. This further supports the applicability of the two-correlation length model and our interpretation. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37830. EASTMAN KODAK CO,ROCHESTER,NY 14650. RP CHEUNG, YW (reprint author), UNIV MASSACHUSETTS,DEPT POLYMER SCI & ENGN,AMHERST,MA 01003, USA. NR 14 TC 44 Z9 44 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 27 PY 1993 VL 26 IS 20 BP 5365 EP 5371 DI 10.1021/ma00072a012 PG 7 WC Polymer Science SC Polymer Science GA LZ505 UT WOS:A1993LZ50500012 ER PT J AU PEKALA, RW SCHAEFER, DW AF PEKALA, RW SCHAEFER, DW TI STRUCTURE OF ORGANIC AEROGELS .1. MORPHOLOGY AND SCALING SO MACROMOLECULES LA English DT Article ID FORMALDEHYDE; RESORCINOL AB Small-angle X-ray scattering is used to determine the structure of nanoporous organic aerogels made by the base-catalyzed polymerization of resorcinol and formaldehyde. This study probes the effect of several variables on the morphology of the supercritically dried aerogels including catalyst concentration, monomer concentration, acid aging, and pyrolysis. In addition, the development of structure during polymerization and aging of the precursor aquagels is reported. The data are consistent with a smooth-surfaced morphology with no indication of fractal clusters or rough surfaces in the length-scale regime from 10 to 600 angstrom. These results, taken together, indicate that microphase separation is the dominant process underlying the morphology of these unique materials. C1 LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550. SANDIA NATL LABS,DEPT MAT RES ENERGY & ENVIRONM TECHNOL,ALBUQUERQUE,NM 87185. NR 20 TC 182 Z9 191 U1 6 U2 35 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 27 PY 1993 VL 26 IS 20 BP 5487 EP 5493 DI 10.1021/ma00072a029 PG 7 WC Polymer Science SC Polymer Science GA LZ505 UT WOS:A1993LZ50500029 ER PT J AU BIGI, II GABBIANI, F KHOZE, VA AF BIGI, II GABBIANI, F KHOZE, VA TI PHOTON LINEAR COLLIDERS AS ALADDIN LAMP - NOVEL PROBES OF QCD IN T(T)OVER-BAR PHYSICS SO NUCLEAR PHYSICS B LA English DT Article ID THRESHOLD BEHAVIOR; E+E-ANNIHILATION; HEAVY QUARKS; PAIR AB S-wave and P-wave production cross sections of top quarks in the threshold region are obtained from perturbative QCD in terms of m(t), GAMMA(t) and alpha(S). S-wave production is described in terms of the Green function for the ttBAR system whereas P-wave production depends on the second space derivatives of the ttBAR Green function. We show by explicit calculation that those relativistic corrections that a priori could affect specifically the non-S-wave production are quite insignificant if top decays mainly like t --> bW or t --> bH with H denoting a charge Higgs state. A comparison of the S-wave and P-wave case thus provides a novel probe of QCD as it affects top dynamics. Collisions of polarized photons off each other allow us to extract separately the S-wave and P-wave production cross section. Such polarized photon beams can be generated by Compton backscattering laser light off polarized electron and positron beams. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. UNIV DURHAM,DEPT PHYS,DURHAM DH1 3LE,ENGLAND. RP BIGI, II (reprint author), UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556, USA. NR 25 TC 13 Z9 13 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 SEP 27 PY 1993 VL 406 IS 1-2 BP 3 EP 18 DI 10.1016/0550-3213(93)90158-L PG 16 WC Physics, Particles & Fields SC Physics GA MA031 UT WOS:A1993MA03100001 ER PT J AU QIAN, YZ FULLER, GM MATHEWS, GJ MAYLE, RW WILSON, JR WOOSLEY, SE AF QIAN, YZ FULLER, GM MATHEWS, GJ MAYLE, RW WILSON, JR WOOSLEY, SE TI CONNECTION BETWEEN FLAVOR MIXING OF COSMOLOGICALLY SIGNIFICANT NEUTRINOS AND HEAVY ELEMENT NUCLEOSYNTHESIS IN SUPERNOVAE SO PHYSICAL REVIEW LETTERS LA English DT Article ID HOT DARK MATTER; R-PROCESS; OSCILLATION EXPERIMENTS; STELLAR COLLAPSE; NEUTRON-STARS; MASS AB We use heavy element nucleosynthesis from supernovae to probe the mixing of nu(e), with nu(tau) (or nu(mu)) possessing cosmologically significant masses (1 to 100 eV). We conclude that the nu(tau)(nu(mu))-nu(e) vacuum mixing angle must satisfy sin(2)2theta< 10(-5), in order to ensure that r-process heavy elements can be produced in neutrino-heated supernova ejecta. Mixing at a level exceeding this limit precludes r-process nucleosynthesis in this site. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF SANTA CRUZ,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064. RP QIAN, YZ (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093, USA. NR 41 TC 201 Z9 200 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 SEP 27 PY 1993 VL 71 IS 13 BP 1965 EP 1968 DI 10.1103/PhysRevLett.71.1965 PG 4 WC Physics, Multidisciplinary SC Physics GA LZ391 UT WOS:A1993LZ39100002 ER PT J AU PARKER, SE LEE, WW SANTORO, RA AF PARKER, SE LEE, WW SANTORO, RA TI GYROKINETIC SIMULATION OF ION-TEMPERATURE-GRADIENT-DRIVEN TURBULENCE IN 3D TOROIDAL GEOMETRY SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARTICLE SIMULATION; INSTABILITIES; TRANSPORT; TOKAMAK AB Results from a fully nonlinear three-dimensional toroidal electrostatic gyrokinetic simulation of the ion temperature gradient instability are presented. The model has adiabatic electrons and the complete gyrophase-averaged ion dynamics, including trapped particles. Results include the confirmation of the radially elongated ballooning mode structure predicted by linear theory, and the nonlinear saturation of these toroidal modes. The ensuing turbulent spectrum retains remnants of the linear mode structure, and has very similar features as recent experimental fluctuation measurements. RP PARKER, SE (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 16 TC 146 Z9 146 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 SEP 27 PY 1993 VL 71 IS 13 BP 2042 EP 2045 DI 10.1103/PhysRevLett.71.2042 PG 4 WC Physics, Multidisciplinary SC Physics GA LZ391 UT WOS:A1993LZ39100021 ER PT J AU CASPARY, R HELLMANN, P KELLER, M SPARN, G WASSILEW, C KOHLER, R GEIBEL, C SCHANK, C STEGLICH, F PHILLIPS, NE AF CASPARY, R HELLMANN, P KELLER, M SPARN, G WASSILEW, C KOHLER, R GEIBEL, C SCHANK, C STEGLICH, F PHILLIPS, NE TI UNUSUAL GROUND-STATE PROPERTIES OF UPD2AL3 - IMPLICATIONS FOR THE COEXISTENCE OF HEAVY-FERMION SUPERCONDUCTIVITY AND LOCAL-MOMENT ANTIFERROMAGNETISM SO PHYSICAL REVIEW LETTERS LA English DT Article ID UNCONVENTIONAL SUPERCONDUCTIVITY; WEAK ANTIFERROMAGNETISM; URU2SI2; CEAL2 AB We report measurements of the resistivity and the specific heat, performed as a function of temperature, magnetic field, and hydrostatic pressure on the antiferromagnetic (T(N)=14 K) heavy-fermion superconductor (T(c)=2 K) UPd2Al3. Our results suggest a coexistence of two subsystems with more localized 5f states responsible for the magnetic properties and less localized states responsible for the superconducting properties. The latter are compatible with an order parameter of octagonal d-wave symmetry. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP CASPARY, R (reprint author), TH DARMSTADT,INST FESTKORPERPHYS,D-64289 DARMSTADT,GERMANY. RI Sparn, Guenter/F-5120-2013 NR 36 TC 130 Z9 131 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 27 PY 1993 VL 71 IS 13 BP 2146 EP 2149 DI 10.1103/PhysRevLett.71.2146 PG 4 WC Physics, Multidisciplinary SC Physics GA LZ391 UT WOS:A1993LZ39100047 ER PT J AU DORIN, VV KLEMM, RA VARLAMOV, AA BUZDIN, AI LIVANOV, DV AF DORIN, VV KLEMM, RA VARLAMOV, AA BUZDIN, AI LIVANOV, DV TI MAGNETIC-FIELD ENHANCEMENT OF THE C-AXIS RESISTIVITY PEAK NEAR T(C) IN LAYERED SUPERCONDUCTORS SO JETP LETTERS LA English DT Article ID SINGLE-CRYSTAL; MAGNETORESISTANCE; ANISOTROPY; YBA2CU3O7; STATE; PLANE AB The contributions to the c-axis conductivity from fluctuations of the normal quasiparticle density of states are opposite in sign to the Aslamazov-Larkin and Maki-Thompson contributions, which lead to a peak in the overall c-axis resistivity rho(c)(T) above T(c). In a magnetic field H parallel-to c, this peak increases in magnitude and is shifted to lower T by an amount proportional to H-2 for weak fields and to H for strong fields. Our results are discussed in regard to recent experiments with YBa2Cu3O7-delta and Bi2Sr2CaCu2O8+delta. C1 TROITSK HIGH PRESSURE PHYS RAS INST,TROITSK 142092,RUSSIA. MOSCOW STEEL & ALLOYS INST,MOSCOW 117936,RUSSIA. RP DORIN, VV (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Buzdin, Alexander/I-6038-2013 NR 21 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-3640 J9 JETP LETT+ JI Jetp Lett. PD SEP 25 PY 1993 VL 58 IS 6 BP 422 EP 426 PG 5 WC Physics, Multidisciplinary SC Physics GA MF777 UT WOS:A1993MF77700004 ER PT J AU GOSZTOLA, D WASIELEWSKI, MR AF GOSZTOLA, D WASIELEWSKI, MR TI RESONANCE RAMAN-SPECTROSCOPY OF A CHLOROPHYLL-PORPHYRIN HETERODIMER - EXCITATION PROFILE IN THE 400-450-NM REGION SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SPHAEROIDES REACTION CENTERS; PI-CATION RADICALS; RHODOPSEUDOMONAS-SPHAEROIDES; SPECTRA; DONOR; LASER; ZINC; MAGNESIUM; TI-AL2O3; COPPER AB Photophysical studies carried out previously on a chlorophyll-porphyrin heterodimer consisting of a zinc methyl pyrochlorophyllide a that is directly bonded at its 3-position to the 5-position of a zinc 2,8,12,18-tetraethyl-3,7,13,17-tetramethyl-15-(p-tolyl)porphyrin have shown that the chlorophyll and porphyrin interact within the excited singlet manifold. Steric hindrance between adjacent substituents rigidly positions the pi systems of both macrocycles perpendicular to one another. A similar orientation occurs between the primary donor and accessory bacteriochlorophyll in the photosynthetic reaction center. To better understand the relationship between the structure and the electronic states of the chlorophyll-porphyrin heterodimer, we have carried out a series of resonance Raman measurements in the Soret band region of the chlorophyll-porphyrin heterodimer. Our data yield the assignment of the two individual Soret bands in the 400-450-nm region to the chlorophyll and porphyrin macrocycles and allow us to characterize the vibrational frequencies present in the ground electronic state of the heterodimer. Coupling the chlorophyll to the porphyrin via the meso position of the porphyrin does not change the vibrational frequencies of the porphyrin from those observed in the corresponding molecule in which a phenyl is attached to the porphyrin meso position. In addition, the vibrational frequencies of the chlorophyll within the heterodimer remain unperturbed from those observed in the chlorophyll alone. Our data are consistent with a ground-state structure for the heterodimer that is very similar to that of its component macrocycles. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 26 TC 6 Z9 6 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 SEP 23 PY 1993 VL 97 IS 38 BP 9599 EP 9602 DI 10.1021/j100140a012 PG 4 WC Chemistry, Physical SC Chemistry GA LY495 UT WOS:A1993LY49500012 ER PT J AU STAVE, MS NICHOLAS, JB AF STAVE, MS NICHOLAS, JB TI DENSITY-FUNCTIONAL STUDY OF CLUSTER-MODELS OF ZEOLITES .1. STRUCTURE AND ACIDITY OF HYDROXYL-GROUPS IN DISILOXANE ANALOGS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID MOLECULAR-ORBITAL CALCULATIONS; PLANE-WAVE METHOD; SELF-CONSISTENT; BASIS-SETS; ABINITIO; SYSTEMS; GEOMETRIES; ENERGIES; OPTIMIZATION; EFFICIENT AB In this work we calculate the structures and acidities of a series of clusters that mimic terminal and bridging hydroxyl groups in zeolites and molecular sieves using the local density functional (LDF) program DMol. The clusters include silanol, H3Si-OH, and its anion, the simplest model of terminal hydroxyl groups at zeolite surfaces and defect sites. We also consider disiloxane, H3Si-O-SiH3, and a series of structural analogs of disiloxane, H3T-O(H)-TH3 (T = tetrahedrally coordinated atom) in which Si is substituted by Al, B, P, Ga, or Ge. The accuracy of these LDF calculations is determined in part by the size of the numerical basis set and quadrature grid. We find that the structures of the clusters are insensitive to increases in quadrature grid size beyond almost-equal-to 3000 points/atom. However, the optimized values of the internal coordinates, particularly the T-O-T bond angle, are much more sensitive to basis set size. The largest basis set used in these calculations (DNP+) shows convergence in key internal coordinates to almost-equal-to 0.1-degrees-5.0-degrees for T-O(H)-T bond angles and better than 0.01 angstrom for T-O bond lengths. We also gauge the accuracy of the LDF results against extended basis set Hartree-Fock MP2 results (MP2/DZ+2d) and experimental data. Agreement between the LDF and MP2/DZ+2d values is generally good, with some notable exceptions. For example, while most of the bond angles are well represented by the LDF, the T-O-T bond angles are systematically 5-degrees-11-degrees smaller than the MP2/DZ+2d results. In addition, we find that the differences between the LDF and MP2/DZ+2dT-O bond lengths correlate with bond strength. Thus, very good agreement between the methods is observed for the stronger Si-O and P-O bonds (<0.005 angstrom), while LDF predicts a significantly shorter (by >0.03 angstrom) length for the weaker B-O bond. Bond lengths involving hydrogen are almost-equal-to 0.02 angstrom too large with the smaller basis sets, although the O-H bond lengths markedly improve with the DNP+ basis set. The theoretical trend in acidity of the hydroxyls, as determined by the proton affinity, agrees with the experimental trend for isomorphously substituted ZSM-5 zeolites and our MP2/DZ+2d results. RP STAVE, MS (reprint author), PACIFIC NW LAB, MOLEC SCI RES CTR, MOLEC SCI SOFTWARE GRP, RICHLAND, WA 99352 USA. NR 60 TC 59 Z9 59 U1 0 U2 8 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 SEP 23 PY 1993 VL 97 IS 38 BP 9630 EP 9641 DI 10.1021/j100140a018 PG 12 WC Chemistry, Physical SC Chemistry GA LY495 UT WOS:A1993LY49500018 ER PT J AU MARKOVIC, N ROSS, PN AF MARKOVIC, N ROSS, PN TI OSCILLATORY BEHAVIOR IN THE ELECTROCHEMICAL OXIDATION OF FORMIC-ACID ON PT(100) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PLATINUM SINGLE-CRYSTALS; ELECTRODES; SURFACES; CO; ELECTROCATALYSIS; ELECTROOXIDATION; ELECTROSORPTION; RECONSTRUCTION; FORMALDEHYDE; MOLECULES AB The electrochemical oxidation of formic acid on Pt was studied in acidic supporting electrolyte using single-crystal electrodes. Very well-defined periodic (not chaotic) current oscillations on a stationary Pt(100) electrode were observed under both potentiodynamic and potentiostatic conditions. The oscillatory behavior is strongly dependent on the Pt surface structure and is seen on the (100) surface but not on the (111) surface. The periodicity, the amplitude, and the absolute magnitude of the current oscillations depends on at least three variables, electrode potential and potential history, formic acid concentration, and the anion of the supporting electrolyte. The pH of the electrolyte was not found to be an important variable, nor was mass transport, e.g. rotation or stirring. The behavior is extremely complex and difficult to analyze in terms of known electrode processes. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 35 TC 47 Z9 47 U1 0 U2 7 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 SEP 23 PY 1993 VL 97 IS 38 BP 9771 EP 9778 DI 10.1021/j100140a039 PG 8 WC Chemistry, Physical SC Chemistry GA LY495 UT WOS:A1993LY49500039 ER PT J AU DEBRECZENY, MP SAUER, K ZHOU, JH BRYANT, DA AF DEBRECZENY, MP SAUER, K ZHOU, JH BRYANT, DA TI MONOMERIC C-PHYCOCYANIN AT ROOM-TEMPERATURE AND 77-K - RESOLUTION OF THE ABSORPTION AND FLUORESCENCE-SPECTRA OF THE INDIVIDUAL CHROMOPHORES AND THE ENERGY-TRANSFER RATE CONSTANTS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID CRYSTAL-STRUCTURE DATA; MASTIGOCLADUS-LAMINOSUS; AGMENELLUM-QUADRUPLICATUM; CYANOBACTERIAL PHYCOBILISOMES; TRANSFER KINETICS; BETA SUBUNITS; ALPHA; POLYPEPTIDES; ASSIGNMENT; STATE AB At both room temperature (RT) and 77 K, the absorption and fluorescence spectra of the three individual chromophore types (alpha84, beta84, and beta155) found in monomeric C-phycocyanin (alpha(PC)beta(PC)), isolated from the cyanobacterium Synechococcus sp. PCC 7002, were resolved along with the rates of energy transfer between the chromophores. The cpcB/C155S mutant, whose PC is missing the beta155 chromophore, was useful in effecting this resolution. At RT, the single broad peak in the visible region of the absorption spectrum of (alpha(PC)beta(PC)) was resolved into its three-component spectra by comparing the steady-state absorption spectra of the isolated wild-type alpha subunit of PC (alpha(PC)) (containing only the alpha84 chromophore) with those of the monomeric PCs isolated from the mutant strain (alpha(PC)beta*) and the wild-type strain (alpha(PC)beta*). At 77 K, the visible region of the absorption spectrum of (alpha(PC)beta(PC)) splits into two peaks. This partial resolution at 77 K of the chromophore spectra of (alpha(PC)beta(PC)) when compared with the 77 K absorption spectra of alpha(PC), beta(PC), and (alpha(PC)beta*) provided a confirmation of our RT assignments of the chromophore absorption spectra. The individual fluorescence spectra of the chromophores and the rate constants for energy transfer between them in (alpha(PC)beta(PC)) were resolved by modeling the time-resolved fluorescence spectra of beta(PC)(containing the beta155 and beta84 chromophores) and (alpha(PC)beta*). As with absorption, lowering the temperature to 77 K helped resolve the fluorescence spectra of the individual chromophores because the spectra were narrowed. C1 LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. PENN STATE UNIV,DEPT MOLEC & CELL BIOL,UNIV PK,PA 16802. PENN STATE UNIV,CTR BIOMOLEC STRUCT & FUNCT,UNIV PK,PA 16802. NR 38 TC 53 Z9 56 U1 0 U2 2 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 SEP 23 PY 1993 VL 97 IS 38 BP 9852 EP 9862 DI 10.1021/j100140a050 PG 11 WC Chemistry, Physical SC Chemistry GA LY495 UT WOS:A1993LY49500050 ER PT J AU NUNOKAWA, H MINAKATA, H AF NUNOKAWA, H MINAKATA, H TI NEUTRINO FLAVOR MIXING, SPIN PRECESSION AND THE SOLAR-NEUTRINO EXPERIMENTS SO PHYSICS LETTERS B LA English DT Article ID MAGNETIC-MOMENT; ELECTROMAGNETIC PROPERTIES; RESONANT AMPLIFICATION; STATISTICAL-ANALYSIS; TIME-DEPENDENCE; MATTER; CHLORINE; GALLEX; FLUX; OSCILLATIONS AB The predictions of the hybrid solution of the solar neutrino problem which combines resonant flavor mixing and spin precession are confronted with the Cl-37, the Kamiokande, and the Ga-71 experiments. In addition to the two known solutions we find new parameter regions which are consistent with the experiments and are characteristic to the hybrid mechanism. We emphasize the importance of measuring low energy neutrinos by BOREXINO and SNO to distinguish these solutions. C1 KEK,DEPT PHYS,NATL LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 305,JAPAN. FERMILAB NATL ACCELERATOR LAB,THEORY GRP,BATAVIA,IL 60510. RP NUNOKAWA, H (reprint author), TOKYO METROPOLITAN UNIV,DEPT PHYS,1-1 MINAMI OSAWA,HACHIOJI,TOKYO 19203,JAPAN. NR 36 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 SEP 23 PY 1993 VL 314 IS 3-4 BP 371 EP 376 DI 10.1016/0370-2693(93)91251-H PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY525 UT WOS:A1993LY52500021 ER PT J AU ROSENSTEIN, B YU, HL KOVNER, A AF ROSENSTEIN, B YU, HL KOVNER, A TI CRITICAL EXPONENTS OF NEW UNIVERSALITY CLASSES SO PHYSICS LETTERS B LA English DT Article ID RENORMALIZATION-GROUP EQUATIONS; QUANTUM-FIELD THEORY; 4-FERMION INTERACTION; 2+1 DIMENSIONS; TRANSITIONS; TEMPERATURE; COUPLINGS; MODEL; SPIN; QCD AB We calculate critical exponents of chiral Ising, XY and Heisenberg universality classes up to second order in 4 - epsilon expansion. General expressions for any number N of fermionic variables are given and compared with recent extensive 1/N calculation and lattice simulations. The possibility that these new universality classes describe critical phenomena in certain 3D magnetic systems and in finite temperature phase transitions of 3 + 1 dimensional quantum field theories is briefly discussed. C1 LOS ALAMOS NATL LAB, DIV THEORY, LOS ALAMOS, NM 87545 USA. RP ACAD SINICA, INST PHYS, TAIPEI 11529, TAIWAN. NR 28 TC 25 Z9 25 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD SEP 23 PY 1993 VL 314 IS 3-4 BP 381 EP 386 DI 10.1016/0370-2693(93)91253-J PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY525 UT WOS:A1993LY52500023 ER PT J AU ORNIK, U PLUMER, M STROTTMAN, D AF ORNIK, U PLUMER, M STROTTMAN, D TI BOSE-CONDENSATION THROUGH RESONANCE DECAY SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; PION INTERFEROMETRY; ENHANCEMENT; KINETICS; PLASMA AB We show that a system described by an equation of state which contains a high number of degrees of freedom (resonances) can create a considerable amount of superfluid (condensed) pions through the decay of short-lived resonances, if baryon number and entropy are large and the dense matter decouples from chemical equilibrium earlier than from thermal equilibrium. The system cools down faster in the presence of a condensate, an effect that may partially compensate the enhancement of the lifetime expected in the case of quark-gluon-plasma formation. C1 UNIV MARBURG,DEPT PHYS,W-3550 MARBURG,GERMANY. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP ORNIK, U (reprint author), GESELL SCHWERIONENFORSCH MBH,THEORY GRP,W-6100 DARMSTADT 11,GERMANY. NR 21 TC 9 Z9 9 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 SEP 23 PY 1993 VL 314 IS 3-4 BP 401 EP 407 DI 10.1016/0370-2693(93)91257-N PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY525 UT WOS:A1993LY52500027 ER PT J AU ANSELMANN, P HAMPEL, W HEUSSER, G KIKO, J KIRSTEN, T LAUBENSTEIN, M PERNICKA, E PEZZONI, S PLAGA, R RONN, U SANN, M SCHLOSSER, C WINK, R WOJCIK, M VONAMMON, R EBERT, KH FRITSCH, T HELLRIEGEL, K HENRICH, E STIEGLITZ, L WEYRICH, F BALATA, M FERRARI, N LALLA, H BELLOTTI, E CATTADORI, C CREMONESI, O FIORINI, E ZANOTTI, L ALTMANN, M VONFEILITZSCH, F MOSSBAUERZ, R SCHANDA, U BERTHOMIEU, G SCHATZMAN, E CARMI, I DOSTROVSKY, I BACCI, C BELLI, P BERNABEI, R DANGELO, S PAOLUZI, L CHARBIT, S CRIBIER, M DUPONT, G GOSSET, L RICH, J SPIRO, M STOLARCZYK, T TAO, C VIGNAUD, D HAHN, RL HARTMANN, FX ROWLEY, JK STOENNER, RW WENESER, J AF ANSELMANN, P HAMPEL, W HEUSSER, G KIKO, J KIRSTEN, T LAUBENSTEIN, M PERNICKA, E PEZZONI, S PLAGA, R RONN, U SANN, M SCHLOSSER, C WINK, R WOJCIK, M VONAMMON, R EBERT, KH FRITSCH, T HELLRIEGEL, K HENRICH, E STIEGLITZ, L WEYRICH, F BALATA, M FERRARI, N LALLA, H BELLOTTI, E CATTADORI, C CREMONESI, O FIORINI, E ZANOTTI, L ALTMANN, M VONFEILITZSCH, F MOSSBAUERZ, R SCHANDA, U BERTHOMIEU, G SCHATZMAN, E CARMI, I DOSTROVSKY, I BACCI, C BELLI, P BERNABEI, R DANGELO, S PAOLUZI, L CHARBIT, S CRIBIER, M DUPONT, G GOSSET, L RICH, J SPIRO, M STOLARCZYK, T TAO, C VIGNAUD, D HAHN, RL HARTMANN, FX ROWLEY, JK STOENNER, RW WENESER, J TI GALLEX SOLAR-NEUTRINO OBSERVATIONS - THE RESULTS FROM GALLEX-I AND EARLY RESULTS FROM GALLEX-II SO PHYSICS LETTERS B LA English DT Article AB The first period (GALLEX I) of data taking in the GALLEX solar neutrino experiment has been completed. From 14 May 1991 to 29 April 1992, the experiment observed the solar neutrino flux using neutrino capture by Ga-71 to form Ge-71. Counting ended on 2 November 1992. The final result from the 15 runs of this period is (81 +/- 17 [stat.] +/- 9 [syst.]) SNU (1sigma). The first 6 runs of GALLEX II recorded the neutrino signal from 19 August 1992 to 3 February 1993. The preliminary result for this period is (97 +/- 23 [stat.] +/- 7 [syst.]) SNU (1sigma). With counting data considered until 29 April 1993, the joint result for all 21 runs is (87 +/- 14 [stat.] +/- 7 [syst.]) SNU (1sigma). The present neutrino recording period GALLEX II is continuing with one solar exposure every four weeks. C1 KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH,INST HEISSE CHEM,W-7500 KARLSRUHE 1,GERMANY. LAB NAZL GRAN SASSO,I-67010 LAQUILA,ITALY. TECH UNIV MUNICH,DEPT PHYS E15,D-85748 GARCHING,GERMANY. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. INFN,I-20133 MILAN,ITALY. OBSERV COTE AZUR,DEPT CASSINI,F-06004 NICE 4,FRANCE. WEIZMANN INST SCI,DEPT ENVIRONM & ENERGY RES,IL-76100 REHOVOT,ISRAEL. UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS 2,I-00133 ROME,ITALY. INFN,I-00133 ROME,ITALY. CENS,DAPNIA,SERV PHYS PARTICULES,F-91191 GIF SUR YVETTE,FRANCE. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP ANSELMANN, P (reprint author), MAX PLANCK INST KERNPHYS,POSTFACH 103980,D-69029 HEIDELBERG,GERMANY. RI Belli, Pierluigi/H-1942-2012; Laubenstein, Matthias/C-4851-2013; Bernabei, Rita/C-1212-2016; OI Belli, Pierluigi/0000-0003-4517-4891; Laubenstein, Matthias/0000-0001-5390-4343; Bernabei, Rita/0000-0003-1786-5396; cattadori, carla maria/0000-0001-7885-6253 NR 25 TC 146 Z9 146 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 SEP 23 PY 1993 VL 314 IS 3-4 BP 445 EP 458 DI 10.1016/0370-2693(93)91264-N PG 14 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY525 UT WOS:A1993LY52500034 ER PT J AU FRABETTI, PL CHEUNG, HWK CUMALAT, JP DALLAPICCOLA, C GINKEL, JF GREENE, SV JOHNS, WE NEHRING, MS BUTLER, JN CIHANGIR, S GAINES, I GARBINCIUS, PH GARREN, L GOURLAY, SA HARDING, DJ KASPER, P KREYMER, A LEBRUN, P SHUKLA, S VITTONE, M BIANCO, S FABBRI, FL SARWAR, S ZALLO, A CULBERTSON, R GARDNER, RW GREENE, R WISS, J ALIMONTI, G BELLINI, G CACCIANIGA, B CINQUINI, L DICORATO, M GIAMMARCHI, M INZANI, P LEVERARO, F MALVEZZI, S MENASCE, D MERONI, E MORONI, L PEDRINI, D PERASSO, L SALA, A SALA, S TORRETTA, D BUCHHOLZ, D CLAES, D GOBBI, B OREILLY, B BISHOP, JM CASON, NM KENNEDY, CJ KIM, GN LIN, TF PUSELJIC, DL RUCHTI, RC SHEPHARD, WD SWIATEK, JA WU, ZY ARENA, V BOCA, G CASTOLDI, C GIANINI, G RATTI, SP RICCARDI, C VITULO, P LOPEZ, A GRIM, GP PAOLONE, VS YAGER, PM WILSON, JR SHELDON, PD DAVENPORT, F FILASETA, JF BLACKETT, GR PISHARODY, M HANDLER, T CHEON, BG KANG, JS KIM, KY AF FRABETTI, PL CHEUNG, HWK CUMALAT, JP DALLAPICCOLA, C GINKEL, JF GREENE, SV JOHNS, WE NEHRING, MS BUTLER, JN CIHANGIR, S GAINES, I GARBINCIUS, PH GARREN, L GOURLAY, SA HARDING, DJ KASPER, P KREYMER, A LEBRUN, P SHUKLA, S VITTONE, M BIANCO, S FABBRI, FL SARWAR, S ZALLO, A CULBERTSON, R GARDNER, RW GREENE, R WISS, J ALIMONTI, G BELLINI, G CACCIANIGA, B CINQUINI, L DICORATO, M GIAMMARCHI, M INZANI, P LEVERARO, F MALVEZZI, S MENASCE, D MERONI, E MORONI, L PEDRINI, D PERASSO, L SALA, A SALA, S TORRETTA, D BUCHHOLZ, D CLAES, D GOBBI, B OREILLY, B BISHOP, JM CASON, NM KENNEDY, CJ KIM, GN LIN, TF PUSELJIC, DL RUCHTI, RC SHEPHARD, WD SWIATEK, JA WU, ZY ARENA, V BOCA, G CASTOLDI, C GIANINI, G RATTI, SP RICCARDI, C VITULO, P LOPEZ, A GRIM, GP PAOLONE, VS YAGER, PM WILSON, JR SHELDON, PD DAVENPORT, F FILASETA, JF BLACKETT, GR PISHARODY, M HANDLER, T CHEON, BG KANG, JS KIM, KY TI EVIDENCE OF THE CABIBBO-SUPPRESSED DECAY LAMBDA(C)(+)-]PK-K+ SO PHYSICS LETTERS B LA English DT Article AB We report evidence for the Cabibbo-suppressed decay of the charm baryon LAMBDA(c)+ into the final state pK-K+. The analysis is performed on data collected by high energy photoproduction experiment E687 during the 1990-1991 Fermilab fixed target run. The branching ratio of the decay LAMBDA(c)+ --> pK-K+ relative to the non-suppressed LAMBDA(c)+ --> pK-pi+ is measured to be BR(pK-K+/pK-pi+) =0.096 +/- 0.029 +/- 0.010. The upper limit of the decay into p(phi) relative to the inclusive pK-K+ decay is measured to be BR(pphi/pK-K+) < 58% at the 90% confidence level. C1 INFN,I-40126 BOLOGNA,ITALY. UNIV COLORADO,BOULDER,CO 80309. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. INFN,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV ILLINOIS,URBANA,IL 61801. INFN,I-20133 MILAN,ITALY. UNIV MILAN,I-20133 MILAN,ITALY. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. INFN,I-27100 PAVIA,ITALY. DIPARTIMENTO FIS TEORICA & NUCL,I-27100 PAVIA,ITALY. UNIV PUERTO RICO,MAYAGUEZ,PR 00708. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV S CAROLINA,COLUMBIA,SC 29208. VANDERBILT UNIV,NASHVILLE,TN 37235. UNIV N CAROLINA,ASHEVILLE,NC 28804. NO KENTUCKY UNIV,HIGHLAND HTS,KY 41076. UNIV TENNESSEE,KNOXVILLE,TN 37996. KOREA UNIV,SEOUL 136701,SOUTH KOREA. RP FRABETTI, PL (reprint author), UNIV BOLOGNA,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. NR 5 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 23 PY 1993 VL 314 IS 3-4 BP 477 EP 481 DI 10.1016/0370-2693(93)91267-Q PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY525 UT WOS:A1993LY52500037 ER PT J AU OGURA, T TAKAHASHI, S HIROTA, S SHINZAWAITOH, K YOSHIKAWA, S APPELMAN, EH KITAGAWA, T AF OGURA, T TAKAHASHI, S HIROTA, S SHINZAWAITOH, K YOSHIKAWA, S APPELMAN, EH KITAGAWA, T TI TIME-RESOLVED RESONANCE RAMAN ELUCIDATION OF THE PATHWAY FOR DIOXYGEN REDUCTION BY CYTOCHROME-C-OXIDASE SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID HEME-LINKED IONIZATION; PI-CATION RADICALS; ELECTRON-PARAMAGNETIC-RESONANCE; PEROXIDASE COMPOUND-II; HORSERADISH-PEROXIDASE; STRETCHING VIBRATION; FE-IV=O; OXYGEN INTERMEDIATE; AMBIENT-TEMPERATURE; ROOM-TEMPERATURE AB Time-resolved resonance Raman (RR) spectra were observed for catalytic intermediates of bovine cytochrome c oxidase at room temperature by using an Artificial Cardiovascular System for Enzymatic Reactions and Raman/Absorption Simultaneous Measurement Device. The isotope-frequency-shift data using an asymmetrically labeled dioxygen, (OO)-O-16-O-18, established that the primary intermediate (compound A) is an end-on-type dioxygen adduct of cytochrome a3. Higher resolution RR experiments revealed that the approximately 800-cm-1 band assigned previously to the Fe(IV)=O stretching mode of the subsequent intermediate (compound B) was actually composed of two bands that behaved differently upon deuteration. The 804/764-cm-1 pair for the O-16(2)/O-18(2) derivatives were insensitive to deuteration, and these bands became noticeably stronger at higher temperatures. In contrast, the 785/751-cm-1 pair for the O-16(2)/O-18(2) derivatives was shifted to 796/766 cm-1 in D2O, and its intensity became virtually zero at 30-degrees-C. The corresponding bands for the (OO)-O-16-O-18 derivative appeared at nearly the same frequencies as those of the O-16(2) and O-18(2) derivatives but not at an intermediate frequency. Therefore, neither of these bands could be attributed to the O-O stretching mode. Normal coordinate calculations using a set of suitable force constants of the Urey-Bradley-Shimanouchi force field for an isolated Fe-O-O-H group could explain the 785/751-cm-1 bands in terms of the Fe-O stretching vibration, although this model assumed a relatively strengthened Fe-O bond and weakened O-O bond for the Fe-O-O-H group. The 804/764-cm-1 bands were assigned to the Fe(IV)=O stretching mode of the ferryl intermediate. The 356/342-cm-1 pair for the O-16(2)/O-18(2) derivatives was insensitive to deuteration, and its frequencies were the same as those obtained with (OO)-O-16-O-18. The intensities of the components of this pair were appreciable even when those of the 785/751-cm-1 pair were zero. Therefore, contrary to the previous assignment, the 356/342-cm-1 pair cannot be ascribed to the hydroperoxy intermediate, but its intensity behavior with temperature was also not coincident with that of the 804/764-cm-1 pair. Although the assignment of the 356/342-cm-1 pair is yet to be determined, the present experiments have conclusively established that the main pathway for dioxygen reduction by cytochrome c oxidase is Fe(II)-O2 --> Fe(III)-O-O-H --> Fe(IV)=O --> Fe(III)-OH and that their key bands for the O-16(2)/O-18(2) pair are at 571/544, 785/751, 804/764, and 450/425 cm-1, respectively. C1 GRAD UNIV ADV STUDIES,DEPT FUNCT MOLEC SCI,OKAZAKI NATL RES INST,INST MOLEC SCI,MYODAIJI,OKAZAKI 444,JAPAN. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. HIMEJI INST TECHNOL,FAC SCI,DEPT LIFE SCI,KAMIGORI,HYOGO 67812,JAPAN. NR 79 TC 102 Z9 102 U1 1 U2 9 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 SEP 22 PY 1993 VL 115 IS 19 BP 8527 EP 8536 DI 10.1021/ja00072a002 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA LZ133 UT WOS:A1993LZ13300002 ER PT J AU WEYDERT, M ANDERSEN, RA BERGMAN, RG AF WEYDERT, M ANDERSEN, RA BERGMAN, RG TI REACTIONS OF (MEC5H4)3U(T-BU) - INTERMOLECULAR FLUORINE ATOM ABSTRACTION FROM FLUOROCARBONS INCLUDING SATURATED PERFLUOROCARBONS SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID BOND DISRUPTION ENTHALPIES; F-ELEMENT THERMOCHEMISTRY; ACTIVATION; HYDROCARBYLS; HEXAFLUOROBENZENE; DEFLUORINATION; COMPLEXES; CHARACTER; HYDRIDES; URANIUM C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 24 TC 56 Z9 56 U1 0 U2 8 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 SEP 22 PY 1993 VL 115 IS 19 BP 8837 EP 8838 DI 10.1021/ja00072a046 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA LZ133 UT WOS:A1993LZ13300046 ER PT J AU BRITT, BM AF BRITT, BM TI A SHIFTING SPECIFICITY MODEL FOR ENZYME CATALYSIS SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID ALPHA-CHYMOTRYPSIN; CLEAVED BOND; HYDROLYSIS; REACTIVITY RP BRITT, BM (reprint author), LOS ALAMOS NATL LAB,INC-14,MS C34S,LOS ALAMOS,NM 87545, USA. NR 21 TC 20 Z9 20 U1 0 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 SEP 21 PY 1993 VL 164 IS 2 BP 181 EP 190 DI 10.1006/jtbi.1993.1147 PG 10 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA MC980 UT WOS:A1993MC98000004 PM 8246515 ER PT J AU CHANG, JJ AF CHANG, JJ TI PRESSURE-DEPENDENCE OF COPPER LASER OUTPUT CHARACTERISTICS SO APPLIED OPTICS LA English DT Article DE METAL-VAPOR LASER; COPPER-VAPOR LASER; LASER PLASMA; LASER BEAM AB Output characteristics of a large-bore (8-cm-diameter) copper laser were analyzed at different neon pressures. Radial delay decreased from approximately 40 ns at 30 Torr to approximately 10 ns at 110 Torr because of increased plasma impedance. When the laser was running as an amplifier, the best power was achieved at approximately 80 Torr (small-bore copper lasers normally optimize at 30-40 Torr). This occurs because a more pronounced reduction of radial delay at higher pressures can be achieved in large-bore devices. As a result, a more uniform beam profile was obtained at higher pressures because of more efficient axial pumping. The improved coupling between the laser head and the pulse modulator at higher pressures also translates to a substantial improvement in laser efficiency (> 50%) as the pressure rises from 30 to 100 Torr. The same laser optimizes at a much lower pressure (30-40 Torr) when its energy is extracted with a flat-flat resonator, because resonator loss increases with increasing gas pressure because of faster gain rise time at higher pressures. RP CHANG, JJ (reprint author), LAWRENCE LIVERMORE NATL LAB, POB 5508, MS L-464, LIVERMORE, CA 94551 USA. NR 9 TC 16 Z9 16 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD SEP 20 PY 1993 VL 32 IS 27 BP 5230 EP 5235 PG 6 WC Optics SC Optics GA LX590 UT WOS:A1993LX59000005 PM 20856330 ER PT J AU SUTTON, SB ALBRECHT, GF AF SUTTON, SB ALBRECHT, GF TI OPTICAL DISTORTION IN END-PUMPED SOLID-STATE ROD LASERS SO APPLIED OPTICS LA English DT Article ID ND-YAG LASER; OPTIMIZATION; RESONATORS; MODE AB We explore the thermo-optical issues of mode-matched end-pumped lasers. A combination of analytical and numerical methods is used to extract practically useful scaling relations that characterize the thermally induced optical distortions and the thermal-stress operating limits in rod lasers pumped with super-Gaussian sources. The thermally induced spherical aberration is found to be overcorrected (focal length increases with radial position), weakly dependent on the axial profile, and strongly dependent on the super-Gaussian order. For high-order radial profiles it is shown that a significant portion of the extraction beam will operate aberration free. The effect of aberrations on cavity stability is addressed for the simple case of a cavity with a length that is equal to the rod length. RP SUTTON, SB (reprint author), LAWRENCE LIVERMORE NATL LAB, POB 808, LIVERMORE, CA 94550 USA. NR 18 TC 9 Z9 12 U1 1 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD SEP 20 PY 1993 VL 32 IS 27 BP 5256 EP 5269 PG 14 WC Optics SC Optics GA LX590 UT WOS:A1993LX59000008 PM 20856333 ER PT J AU SRINIVASANRAO, T FISCHER, J TSANG, T AF SRINIVASANRAO, T FISCHER, J TSANG, T TI OPTICAL-FIELD ENHANCED MULTIPHOTON PHOTOEMISSION IN COPPER MIRRORS SO APPLIED PHYSICS LETTERS LA English DT Article ID LASER-PULSES; ELECTRON; GOLD AB Photoemission from diamond turned copper mirror with laser beams of intensity 10(11) W/cm2 at the photon energy of 2 eV and pulse duration of approximately 300 fs indicates that the electric field associated with the photons enhances the photoemission. At the optimum incident angle, the electron yield with p-polarized light was 75 times larger than that with s-polarized light and 4 times larger than that at normal incidence for a constant energy. These enhancements were underestimated by the changes in the absorption and were attributed in this letter to the optical field effect. RP SRINIVASANRAO, T (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 9 TC 3 Z9 3 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 20 PY 1993 VL 63 IS 12 BP 1595 EP 1597 DI 10.1063/1.110757 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700001 ER PT J AU HOHIMER, JP VAWTER, GA AF HOHIMER, JP VAWTER, GA TI PASSIVE-MODE LOCKING OF MONOLITHIC SEMICONDUCTOR RING LASERS AT 86 GHZ SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL PULSES; DIODE-LASERS AB We report the development of monolithic passively mode-locked semiconductor ring lasers. These direct-waveguide-coupled lasers with a ring radius of 150 mum emit a continuous train of 1.3 ps transform-limited lasing pulses at 86 GHz repetition rate with a peak power of 10 mW/pulse at the laser output facet. We also observe, under certain conditions, the presence of a second pulse in the ring cavity doubling the pulse repetition rate to 172 GHz. RP HOHIMER, JP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 12 TC 29 Z9 30 U1 0 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 SEP 20 PY 1993 VL 63 IS 12 BP 1598 EP 1600 DI 10.1063/1.110808 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700002 ER PT J AU BREWER, MA BROWN, IG EVANS, PJ HOFFMAN, A AF BREWER, MA BROWN, IG EVANS, PJ HOFFMAN, A TI DIAMOND FILM GROWTH ON TI-IMPLANTED GLASSY-CARBON SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; THIN-FILMS; NUCLEATION; SURFACE; SILICON AB The growth of diamond thin films on glassy carbon substrates has been investigated as a function of deposition time for different surface treatments. Implantation of Ti to a dose of 1.7 X 10(17) cm-2 and abrasion with diamond powder have both been examined to determine their effect on film nucleation and growth. At the shorter deposition times studied, diamond nucleation was observed on all test samples with those subjected to the abrasive pretreatment exhibiting the higher growth rates. However, the adhesion and uniformity of films on unimplanted glassy carbon were found to deteriorate significantly following deposition runs of 14 and 21 h duration. This was attributed to a destabilization of the underlying surface caused by plasma erosion. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. ANSTO LUCAS HGTS RES LABS,MENAI,NSW 2234,AUSTRALIA. NR 21 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 20 PY 1993 VL 63 IS 12 BP 1631 EP 1633 DI 10.1063/1.110718 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700013 ER PT J AU MCMAHON, TJ XIAO, Y AF MCMAHON, TJ XIAO, Y TI ELECTRON-SPIN-RESONANCE STUDY OF THE DANGLING BOND IN AMORPHOUS SI AND POROUS SI SO APPLIED PHYSICS LETTERS LA English DT Article ID SI/SIO2 INTERFACE; SILICON; DEFECTS; HYPERFINE AB We compare the electron spin resonance (ESR) signal of the dangling bond in porous silicon (PS) layers, produced by electrochemical etching, to the ESR signal from hydrogenated amorphous Si(a-Si:H) films. The anisotropy of the ESR signal from PS showed g values varying as for the P(b) S/SiO2 interface dangling bond. The g value varies from g(parallel-to) = 2.0020 to g(perpendicular-to) = 2.0080 with an inhomogeneously broadened line width increasing from 1.8 to 3.8 G. An ESR powder line, with superhyperfine and strain broadening intrinsic to PS, has more anisotropy in g(parallel-to) - g(perpendicular-to) and less inhomogeneous broadening than does the dangling bond line in a-Si:H. No evidence was seen for light-induced metastability on a H-passivated PS film. C1 UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309. RP MCMAHON, TJ (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 14 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 SEP 20 PY 1993 VL 63 IS 12 BP 1657 EP 1659 DI 10.1063/1.110727 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700022 ER PT J AU MARTENS, JS PANCE, A CHAR, K LEE, L WHITELEY, S HIETALA, VM AF MARTENS, JS PANCE, A CHAR, K LEE, L WHITELEY, S HIETALA, VM TI SUPERCONDUCTING JOSEPHSON ARRAYS AS TUNABLE MICROWAVE SOURCES OPERATING AT 77-K SO APPLIED PHYSICS LETTERS LA English DT Article ID JUNCTION ARRAYS AB High-temperature superconducting arrays of Josephson junctions have been fabricated and tested as millimeter-wave oscillators at 77 K, Power levels in the microwatt range have been detected in the range of 90-160 GHz from arrays using from 350 to almost 60 000 YBa2Cu3O7 junctions. Monolithic log-periodic spiral antennas as well as quasioptical resonators have been used to enable power coupling. The arrays were also found to be bias tunable over ranges limited by the receiving apparatus. C1 SANDIA NATL LABS,ORG 1322,ALBUQUERQUE,NM 87185. RP MARTENS, JS (reprint author), CONDUCTUS INC,969 W MAUDE AVE,SUNNYVALE,CA 94086, USA. NR 8 TC 34 Z9 36 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 SEP 20 PY 1993 VL 63 IS 12 BP 1681 EP 1683 DI 10.1063/1.110709 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700030 ER PT J AU FULLERTON, EE CONOVER, MJ MATTSON, JE SOWERS, CH BADER, SD AF FULLERTON, EE CONOVER, MJ MATTSON, JE SOWERS, CH BADER, SD TI 150-PERCENT MAGNETORESISTANCE IN SPUTTERED FE/CR(100) SUPERLATTICES SO APPLIED PHYSICS LETTERS LA English DT Article ID BEAM EPITAXIAL-GROWTH; X-RAY-DIFFRACTION; GIANT MAGNETORESISTANCE; STRUCTURAL CHARACTERIZATION; TEMPERATURE-DEPENDENCE; MULTILAYERS; CO/CU; FILMS; AG/FE; AG/CR AB We report the epitaxial growth of Fe/Cr(100) superlattices onto MgO(100) single-crystal substrates by magnetron sputtering. Superlattices that are epitaxially oriented within 1-degrees both in-plane and out-of-plane with the MgO substrate are achieved by initial growth of a Cr base layer at high temperature. Multiple superlattice diffraction peaks are observed in the low- and high-angle x-ray diffraction spectra. Three peaks are observed in the magnetoresistance associated with the oscillatory antiferromagnetic interlayer magnetic coupling as a function of Cr thickness. A maximum magnetoresistance of 150% at 4.2 K (28% at room temperature) is observed for a Cr(100 angstrom)/[Fe(14 angstrom)/Cr(8 angstrom)]50 superlattice. RP FULLERTON, EE (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013; Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 28 TC 88 Z9 88 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 SEP 20 PY 1993 VL 63 IS 12 BP 1699 EP 1701 DI 10.1063/1.110689 PG 3 WC Physics, Applied SC Physics GA LX607 UT WOS:A1993LX60700036 ER PT J AU MILLER, DS WILSON, JR MAYLE, RW AF MILLER, DS WILSON, JR MAYLE, RW TI CONVECTION ABOVE THE NEUTRINOSPHERE IN TYPE-II SUPERNOVAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCELERATION OF PARTICLES; CONVECTION; HYDRODYNAMICS; SHOCK WAVES; STARS, INTERIORS; SUPERNOVAE, GENERAL AB We have completed several two-dimensional calculations of a Type II supernova explosion through the first 0.4 s past bounce to examine the effects of convection on the shock. We have used the two-dimensional code to compute a convective velocity to compare with the Mayle and Wilson (MW) one-dimensional code (which includes more of the relevant physics) and find that the M&W code does not produce an explosion using the two-dimensional convective velocity. We find that convection develops exponentially with a growth rate of approximately 100 s-1. If the initial perturbation is sufficient, this instability grows enough to develop significant convective velocities. The convective eddies then deliver energy to the shock. We present results from several runs with varying sizes of initial perturbation, as well as a case with no initial perturbation but including the effects of rotation. We see that convection enhances the outward propagation of the shock. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP MILLER, DS (reprint author), UNIV CALIF DAVIS,DAVIS,CA 95616, USA. NR 5 TC 81 Z9 82 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 SEP 20 PY 1993 VL 415 IS 1 BP 278 EP 285 DI 10.1086/173163 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LW899 UT WOS:A1993LW89900027 ER PT J AU STEIGMAN, G FIELDS, BD OLIVE, KA SCHRAMM, DN WALKER, TP AF STEIGMAN, G FIELDS, BD OLIVE, KA SCHRAMM, DN WALKER, TP TI POPULATION-II LI-6 AS A PROBE OF NUCLEOSYNTHESIS AND STELLAR STRUCTURE AND EVOLUTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ABUNDANCES; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES; STARS, ABUNDANCES ID HALO-STARS; PRIMORDIAL LITHIUM; DISK-STARS; ABUNDANCE; DWARFS; METALLICITY; BERYLLIUM; OXYGEN; GALAXY; BE-9 AB We discuss the importance of Population II Li-6 as a diagnostic for models of primordial nucleosynthesis, cosmic-ray nucleosyntheses in the early Galaxy, and the structure and evolution of metal-poor solar-type stars. The observation of Li-6 in the subdwarf HD 84937 is shown to be consistent with the existing Population II LiBeB data within the context of a simple three-component model: (1) standard big bang nucleosynthesis, (2) Population II cosmic-ray nucleosynthesis, (3) standard (nonrotating) stellar LiBeB depletion. If this interpretation is correct, we predict a potentially detectable boron abundance for this star: B/H approximately 2 x 10(-12). Subsequent Population II LiBeB observations, and in particular further observations of Population II Li-6, are shown to be crucial to our understanding of the primordial and early galactic creation and destruction mechanisms for light elements. C1 FNAL,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. UNIV CHICAGO,CHICAGO,IL 60637. OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. RP STEIGMAN, G (reprint author), OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210, USA. NR 36 TC 59 Z9 59 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 SEP 20 PY 1993 VL 415 IS 1 BP L35 EP L38 DI 10.1086/187026 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LW901 UT WOS:A1993LW90100009 ER PT J AU DAUM, PH ALSUNAID, A BUSNESS, KM HALES, JM MAZUREK, M AF DAUM, PH ALSUNAID, A BUSNESS, KM HALES, JM MAZUREK, M TI STUDIES OF THE KUWAIT OIL FIRE PLUME DURING MIDSUMMER 1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LONG-RANGE TRANSPORT; CHEMICAL-COMPOSITION; SMOKE PLUME; AEROSOL; PARTICLES; AIRBORNE; CLIMATE; WELLS AB This paper reports aircraft observations of the Kuwait oil fire plume conducted during the period July 31-August 17, 1991. During this study the plume was transported almost exclusively to the south of Kuwait over the Persian Gulf and the Arabian Peninsula. The plume base was generally found to be well above the surface, in some cases as high as 1-2 km; plume tops did not exceed 5 km. Aerosol mass (based on measured aerosol constituents) in the central section of the plume, ca. 150-200 km downwind of the source region, was found to be >500 mug/m3, with number densities in the size range (approximate) 0.2 < d < 3 mum (where d is diameter) as high as 30,000/cm3. The aerosol was composed of (in order of approximate contribution to mass) inorganic salts, elemental carbon, and organic carbon. Sodium chloride constituted a surprisingly large component of the soluble inorganic mass. The aerosol particles appeared to function as good cloud condensation nuclei, with a large fraction of accumulation mode particles (by number) activated at a supersaturation of 0.6%. Under conditions in which the plume was relatively compact, transmittance of solar radiation to the surface was only 10-20%. Plume albedo was observed to be as low as 2-3% close to the source region, consistent with the high elemental-carbon concentrations present in the plume. Trace gas concentrations were consistent with fuel composition and with current knowledge of atmospheric chemical processes. Sulfur dioxide concentrations close to the source region were found to be as high as 3 ppb. The emissions factor for S (expressed as a percentage) was estimated to be 1.8%, which is consistent with estimates of a fuel sulfur content of 2-2.5%. SO2 was found to be only slowly oxidized (<1%/h). Nitrogen oxide concentrations were found to be quite low (<50 ppb near the source, decreasing to 1-2 ppb well downwind), which is consistent with a crude oil nitrogen source. Despite relatively low concentrations, sufficient NO(x) was present to act as a catalyst to generate excess ozone in the plume as the plume was transported downwind and dispersed. RP DAUM, PH (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV ENVIRONM CHEM,UPTON,NY 11973, USA. NR 31 TC 15 Z9 15 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 20 PY 1993 VL 98 IS D9 BP 16809 EP 16827 DI 10.1029/93JD01204 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LY330 UT WOS:A1993LY33000020 ER PT J AU MCGOWAN, FK MILNER, WT AF MCGOWAN, FK MILNER, WT TI COULOMB-EXCITATION OF STATES IN TH-232 SO NUCLEAR PHYSICS A LA English DT Article DE NUCLEAR REACTIONS TH-232(ALPHA,ALPHA(')GAMMA); E = 18 MEV; MEASURED I(GAMMA); E(GAMMA); GAMMA(OMICRON); DEDUCED B(E2); B(M1); B(E3); B(E1); B(E1); J(PI),DELTA ID VIBRATIONAL-LIKE STATES; NUCLEI AB Twenty-five states in Th-232 have been observed with 18 MeV He-4 ions on a thick target. Eleven 2+ states between 774 and 1554 keV and three 3- states are populated by direct E2 and E3, respectively. The remaining states are either weakly excited by multiple Coulomb excitation and/or populated by the decay of the directly excited states. Spin assignments are based on gamma-ray angular distributions. Reduced transition probabilities have been deduced from the gamma-ray yields. The B(E2) values for excitation of the 2+ states range from 0.024 to 3.5 W.u. (222 W.u. for the first 2+ state). For the 3- states, the B(E3,0 --> 3-) values are 1.7, 11, and 24 W.u. A possible two-phonon state at 1554 keV, which is nearly harmonic, decays to four members of the one-phonon states, to the ground-state band, and to the K = 0- octupole band. The B(E2) value for excitation of this state is 0.66 + 0.05 W.u. and the B(E1) values for decay of this state are (2 and 6) X 10(-4) W.u. The B(E2) values between two- and one-phonon vibrational states range between 16 and 53 W.u. which are an order of magnitude larger than the B(E2) values between the one- and zero-phonon states. This disagrees with our present understanding of collectivity in nuclei if this 2+ state is considered to be a collective two-phonon excitation. The 2+ states at 1477 and 1387 keV, which are also nearly harmonic, are possible candidates with two-phonon structure. The agreement between the experimental results and the microscopic calculations by Neergard and Vogel of the B(E3,0 --> 3) for the 3- members of the one-phonon octupole quadruplet is satisfactory when the Coriolis coupling between the states with K and K +/- 1 is included. The B(E1) branching ratios for transitions from the 3- and 1- states to the ground-state band have large deviations from the Alaga-rule predictions. These deviations can be understood by the strong Coriolis coupling between the states of the octupole quadruplet in deformed nuclei. RP MCGOWAN, FK (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 24 TC 17 Z9 17 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 SEP 20 PY 1993 VL 562 IS 2 BP 241 EP 259 DI 10.1016/0375-9474(93)90198-7 PG 19 WC Physics, Nuclear SC Physics GA MB027 UT WOS:A1993MB02700006 ER PT J AU KATANO, S NICKLOW, RM FUNAHASHI, S MORI, N KOBAYASHI, T AKIMITSU, J AF KATANO, S NICKLOW, RM FUNAHASHI, S MORI, N KOBAYASHI, T AKIMITSU, J TI PRESSURE-INDUCED SUCCESSIVE MAGNETIC PHASE-TRANSITIONS IN PR2CUO4-Y SO PHYSICA C LA English DT Article ID SPIN CORRELATIONS; ND2CUO4 AB The effects of pressure on the antiferromagnetic long-range ordering in Pr2CuO4-y have been studied between 0.25 and 0.75 GPa by neutron diffraction experiments at temperatures down to 12 K. Under a pressure of 0.25 GPa, successive magnetic phase transitions are observed at T(N) almost-equal-to 250 K and T1 almost-equal-to 170 K, as was reported previously. Upon further cooling in the present experiments another transition has been found at T2 almost-equal-to 50 K. These magnetic phase transitions can be attributed to spin reorientations induced under high pressure. The temperature T1 increases at a rate of about 40 K/GPa with pressure; on the other hand, T2 decreases greatly at -120 K/GPa. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV TOKYO,INST SOLID STATE PHYS,MINATO KU,TOKYO 106,JAPAN. AOYAMA GAKUIN UNIV,DEPT PHYS,SETAGAYA KU,TOKYO 157,JAPAN. RP KATANO, S (reprint author), JAPAN ATOM ENERGY RES INST,DEPT MAT SCI & ENGN,TOKAI,IBARAKI 31911,JAPAN. NR 12 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD SEP 20 PY 1993 VL 215 IS 1-2 BP 92 EP 96 DI 10.1016/0921-4534(93)90368-Z PG 5 WC Physics, Applied SC Physics GA LY978 UT WOS:A1993LY97800011 ER PT J AU CARLSON, KD KINI, AM SCHLUETER, JA GEISER, U KLEMM, RA WILLIAMS, JM DUDEK, JD CALECA, MA LYKKE, KR WANG, HH FERRARO, JR STOUT, P AF CARLSON, KD KINI, AM SCHLUETER, JA GEISER, U KLEMM, RA WILLIAMS, JM DUDEK, JD CALECA, MA LYKKE, KR WANG, HH FERRARO, JR STOUT, P TI IN SEARCH OF AN ISOTOPE EFFECT ON T(C) IN KAPPA-(ET)2X SUPERCONDUCTORS WITH S-34 ISOTOPIC-SUBSTITUTION IN THE 8 SULFUR-ATOMS OF BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE (ET) SO PHYSICA C LA English DT Article ID PRESSURE ORGANIC SUPERCONDUCTOR; BEDT-TTF; TEMPERATURE; TC; KAPPA-(BEDT-TTF)2CUBR; SUSCEPTIBILITY; CONDUCTORS; TRANSITION; MECHANISM; BEHAVIOR AB We describe the first studies of the superconducting isotope effect with S-34 substitution for all eight sulfur atoms of the ET molecule in kappa-(ET)2Cu[N(CN)2]Br (T(c)=11.6 K) and kappa-(ET)2Cu(NCS)2 (T(c)=9.6 K). The frequencies of two symmetric normal mal mode vibrations associated with the C-S stretching motions (approximately 500 cm-1) of ET decrease by about 2.7% with this substitution. Furthermore, the mass of ET is increased by about 16 amu. A small shift, DELTAT(c)=-0.08+/-0.07 K, indicates that the C-S stretching motions of ET do not provide a dominant exchange mechanism for Cooper pairing. The results rule out the possibility of a conventional BCS isotope effect with ET as the relevant mass entity, but they are consistent with a small BCS mass effect with alpha=0.17+/-0.15 for kappa-(ET)2Cu[N(CN)2]Br. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. BIORAD,DIV DIGILAB,CAMBRIDGE,MA 02137. RP CARLSON, KD (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Kini, Aravinda/F-4467-2012 NR 35 TC 14 Z9 14 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 SEP 20 PY 1993 VL 215 IS 1-2 BP 195 EP 204 DI 10.1016/0921-4534(93)90381-Y PG 10 WC Physics, Applied SC Physics GA LY978 UT WOS:A1993LY97800024 ER PT J AU ZUMBRO, JD MORRIS, CL MCGILL, JA SEESTROM, SJ WHITTON, RM EDWARDS, CM WILLIAMS, AL BRAUNSTEIN, MR KOHLER, MD KRISS, BJ HOIBRATEN, S PETERSON, RJ OUYANG, J WISE, JE GIBBS, WR AF ZUMBRO, JD MORRIS, CL MCGILL, JA SEESTROM, SJ WHITTON, RM EDWARDS, CM WILLIAMS, AL BRAUNSTEIN, MR KOHLER, MD KRISS, BJ HOIBRATEN, S PETERSON, RJ OUYANG, J WISE, JE GIBBS, WR TI INCLUSIVE SCATTERING OF 500 MEV PIONS FROM CARBON SO PHYSICAL REVIEW LETTERS LA English DT Article ID DELTA-RESONANCE; E,E'P REACTION; NUCLEI; EXCITATION AB Inclusive double-differential cross sections for 500-MeV pions are presented for C(pi+/-, pi+/-) at theta(lab) of 30-degrees, 40-degrees, 50-degrees, 70-degrees, and 90-degrees; and for C(pi-, pi-) at 110-degrees. We compare the 50-degrees and 70-degrees data with C(e, e') data at nearly the same momentum transfer. These spectra from very different probes are more similar than expected from an intranuclear cascade calculation, which includes the strong rescattering of pions that have energies near 180 MeV. Agreement of the calculated spectra and the pion data is improved if the nucleus is assumed to be nearly transparent to these pions. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. UNIV TEXAS,AUSTIN,TX 78712. NEW MEXICO STATE UNIV,LAS CRUCES,NM 88003. UNIV COLORADO,BOULDER,CO 80309. RP ZUMBRO, JD (reprint author), MIT,BATES LINEAR ACCELERATOR CTR,MIDDLETON,MA 01949, USA. NR 14 TC 16 Z9 16 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 SEP 20 PY 1993 VL 71 IS 12 BP 1796 EP 1799 DI 10.1103/PhysRevLett.71.1796 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800005 ER PT J AU BEAUSANG, CW FALLON, P CLARKE, S BECK, FA BYRSKI, T CURIEN, D DAGNALL, PJ DEFRANCE, G DUCHENE, G FORSYTH, PD HAAS, B JOYCE, MJ MACCHIAVELLI, AO PAUL, ES SHARPEYSCHAFER, JF SIMPSON, J TWIN, PJ VIVIEN, JP AF BEAUSANG, CW FALLON, P CLARKE, S BECK, FA BYRSKI, T CURIEN, D DAGNALL, PJ DEFRANCE, G DUCHENE, G FORSYTH, PD HAAS, B JOYCE, MJ MACCHIAVELLI, AO PAUL, ES SHARPEYSCHAFER, JF SIMPSON, J TWIN, PJ VIVIEN, JP TI DEGENERATE SUPERDEFORMED STATES IN GD-150 SO PHYSICAL REVIEW LETTERS LA English DT Article ID BANDS; NUCLEI; EUROGAM; ARRAY AB The superdeformed (SD) structure of 150Gd has been studied using the Eurogam gamma-ray spectrometer and three new SD bands have been discovered. An interaction is observed between two of the SD bands caused by the near degeneracy of two levels. This is the first observation of accidental degeneracy between SD states. The interaction strength is determined to be 11 keV and evidence for cross talk between the bands is observed. The absolute energy difference between two SD states in the second minimum has been accurately measured and the relative spins and parities of the two bands have been fixed. C1 CTR RECH NUCL,F-67037 STRASBOURG,FRANCE. LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. SERC,DARESBURY LAB,SCI & ENGN RES COUNCIL,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. RP BEAUSANG, CW (reprint author), UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BX,ENGLAND. RI CURIEN, Dominique/B-6718-2013 NR 16 TC 29 Z9 29 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 SEP 20 PY 1993 VL 71 IS 12 BP 1800 EP 1803 DI 10.1103/PhysRevLett.71.1800 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800006 ER PT J AU MAZZUCATO, E NAZIKIAN, R AF MAZZUCATO, E NAZIKIAN, R TI RADIAL SCALE LENGTH OF TURBULENT FLUCTUATIONS IN THE MAIN CORE OF TFTR PLASMAS SO PHYSICAL REVIEW LETTERS LA English DT Article ID DENSITY-FLUCTUATIONS; TOKAMAK; SPECTRUM AB A new theory of microwave reflectometry is applied to turbulence measurements in the TFTR tokamak. Results indicate that in the main core of neutral beam heated plasmas in the supershot regime, the radial correlation length of density fluctuations is a weak decreasing function of heating power in the range 2-4 cm. Over the same interval of heating powers (0-14 MW), the level of density fluctuations is observed to steadily increase by more than an order of magnitude. RP PRINCETON UNIV, PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. NR 13 TC 114 Z9 117 U1 1 U2 8 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 SEP 20 PY 1993 VL 71 IS 12 BP 1840 EP 1843 DI 10.1103/PhysRevLett.71.1840 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800016 ER PT J AU WEISS, W BARBIERI, A VANHOVE, MA SOMORJAI, GA AF WEISS, W BARBIERI, A VANHOVE, MA SOMORJAI, GA TI SURFACE-STRUCTURE DETERMINATION OF AN OXIDE FILM GROWN ON A FOREIGN SUBSTRATE - FE3O4 MULTILAYER ON PT(111) IDENTIFIED BY LOW-ENERGY-ELECTRON DIFFRACTION SO PHYSICAL REVIEW LETTERS LA English DT Article ID TENSOR LEED; OXIDATION; RELAXATION; IRON AB For the first time a detailed surface structure determination is reported for an oxide film grown on a foreign metal substrate. Well-ordered iron oxide films were grown onto Pt(111) substrates and were identified by a dynamical low energy electron diffraction analysis to be magnetite, Fe3O4. They form an unreconstructed polar (111) surface termination that exposes 1/4 monolayer of Fe ions over a distorted hexagonal close-packed oxygen layer and minimizes the number of dangling bonds. The surface also exhibits large relaxations that may be driven by electrostatic forces. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP WEISS, W (reprint author), LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 30 TC 134 Z9 135 U1 1 U2 20 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 SEP 20 PY 1993 VL 71 IS 12 BP 1848 EP 1851 DI 10.1103/PhysRevLett.71.1848 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800018 ER PT J AU BULAEVSKII, LN KOLESNIKOV, NN SCHEGOLEV, IF VYASELEV, OM AF BULAEVSKII, LN KOLESNIKOV, NN SCHEGOLEV, IF VYASELEV, OM TI EFFECT OF VORTEX FLUCTUATIONS ON TL-205 SPIN-LATTICE RELAXATION IN THE MIXED-STATE OF TL2BA2CUO6 SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTORS; VORTICES AB The spin-lattice relaxation rate W on Tl-205 has been measured in the mixed state of a Tl2Ba2CuO6 aligned powder sample with T(c) = 100 K. At T < 25 K, W is-proportional-to T and decreases with increasing magnetic field. This behavior is explained as caused by fluctuations of pancake vortices; the latter induce a time dependent random magnetic field which causes the relaxation of nuclear spins. C1 RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,RUSSIA. RP BULAEVSKII, LN (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 18 TC 49 Z9 49 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 SEP 20 PY 1993 VL 71 IS 12 BP 1891 EP 1894 DI 10.1103/PhysRevLett.71.1891 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800029 ER PT J AU BILLINGE, SJL KWEI, GH LAWSON, AC THOMPSON, JD TAKAGI, H AF BILLINGE, SJL KWEI, GH LAWSON, AC THOMPSON, JD TAKAGI, H TI SUPERCONDUCTIVITY AND THE LOW-TEMPERATURE ORTHORHOMBIC TO TETRAGONAL PHASE-TRANSITION IN LA2-XBAXCUO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSPORT AB The relationship between the low-temperature orthorhombic-tetragonal (OT) phase transition in La2-xBaxCuO4 and the suppression of the superconducting state in samples with x = 0.125 has been investigated. Using high resolution synchrotron x-ray diffraction we show that the phase composition of a superconducting x = 0.15 sample varies with temperature identically to an x = 0.125 sample. This shows that the tetragonal structure does support bulk superconductivity in La2-xBaxCuO4 and the electronic transition which suppresses superconductivity at x = 0.125 is distinct from the OT structural transition. C1 UNIV TOKYO,DEPT APPL PHYS,BUNKYO KU,TOKYO 113,JAPAN. RP BILLINGE, SJL (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Takagi, Hidenori/B-2935-2010 NR 27 TC 41 Z9 43 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 SEP 20 PY 1993 VL 71 IS 12 BP 1903 EP 1906 DI 10.1103/PhysRevLett.71.1903 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800032 ER PT J AU AUMAYR, F KURZ, H SCHNEIDER, D BRIERE, MA MCDONALD, JW CUNNINGHAM, CE WINTER, HP AF AUMAYR, F KURZ, H SCHNEIDER, D BRIERE, MA MCDONALD, JW CUNNINGHAM, CE WINTER, HP TI EMISSION OF ELECTRONS FROM A CLEAN GOLD SURFACE-INDUCED BY SLOW, VERY HIGHLY-CHARGED IONS AT THE IMAGE CHARGE ACCELERATION LIMIT SO PHYSICAL REVIEW LETTERS LA English DT Article ID METAL-SURFACE; HOLLOW ATOMS; AR IONS; ABOVE-SURFACE; NEUTRALIZATION; TUNGSTEN; TRAP AB Total low-energy electron yields for the normal incidence interaction of slow very highly charged ions (Xe-136q+, 21 less-than-or-equal-to q less-than-or-equal-to 51; Th-232q+, 51 less-than-or-equal-to q less-than-or-equal-to 80) with a clean gold surface have been determined from the related measured electron emission statistics. The projectile impact energies could be reduced down to the image charge acceleration limit. The electron emission yield was found to increase proportionally with the increasing projectile charge state in all cases studied, suggesting no saturation in the ability of the Au target to provide necessary electrons within the above surface interaction time (e.g., about 280 electrons/projectile for Th79+ in less than 10(-13) s). Because of the relatively narrow energy distribution and very high charge states of the incident ions, the first clear measurements of image charge acceleration from electron emission yields could be performed. Results of a quantitative study of this acceleration are in good agreement with those of a theoretical model recently developed by J. Burgdorfer et al. C1 VIENNA TECH UNIV,INST ALLGEMEINE PHYS,A-1040 VIENNA,AUSTRIA. RP AUMAYR, F (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Aumayr, Friedrich/A-3920-2009 OI Aumayr, Friedrich/0000-0002-9788-0934 NR 34 TC 137 Z9 140 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 SEP 20 PY 1993 VL 71 IS 12 BP 1943 EP 1946 DI 10.1103/PhysRevLett.71.1943 PG 4 WC Physics, Multidisciplinary SC Physics GA LY018 UT WOS:A1993LY01800042 ER PT J AU GOUDER, T COLMENARES, CA AF GOUDER, T COLMENARES, CA TI A SURFACE SPECTROSCOPY STUDY OF THIN-LAYERS OF URANIUM ON POLYCRYSTALLINE PALLADIUM SO SURFACE SCIENCE LA English DT Article ID ELECTRONIC-STRUCTURE; 5F LOCALIZATION; CROSS-SECTIONS; PD ALLOYS; UPD3; NI AB Thin layers of U on polycrystalline Pd have been prepared by magnetron sputter deposition at room temperature. Mode of growth, annealing induced surface rearrangement, bulk diffusion and the electronic structure of the surface have been investigated by AES, XPS and UPS. It was shown that for U coverages well below one monolayer the decreased coordination at the surface produces localization of the 5f electrons in U. At low dosages U stays on the top surface, while at higher coverages near-surface diffusion takes place, even at room temperature. Strong chemical interaction between deposited U and Pd was detected by the surface core level shifts of the Pd 3d line and by the evolution of the Pd valence band. At dosages above one monolayer, the U 5f electrons are clearly delocalized. Annealing triggers diffusion of U into Pd. Two types of diffusion were observed: one at temperatures below 250-degrees-C which results in U-Pd surface compound formation and one at temperatures above 500-degrees-C which is associated with bulk diffusion of U. Low temperature diffusion is thought to result in non-stoichiometric UPd3. RP GOUDER, T (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 15 Z9 18 U1 2 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 SEP 20 PY 1993 VL 295 IS 1-2 BP 241 EP 250 DI 10.1016/0039-6028(93)90200-4 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LX840 UT WOS:A1993LX84000030 ER PT J AU ERCK, R AF ERCK, R TI BOOZY BLAST 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 SEP 18 PY 1993 VL 139 IS 1891 BP 49 EP 49 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LY340 UT WOS:A1993LY34000046 ER PT J AU JONES, RB ALLMAN, SL TANG, K GARRETT, WR CHEN, CH AF JONES, RB ALLMAN, SL TANG, K GARRETT, WR CHEN, CH TI NEUTRALIZATION OF NEGATIVELY CHARGED OLIGONUCLEOTIDES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DESORPTION MASS-SPECTROMETRY; LASER ABLATION; MATRIX; ACIDS AB Negative ions of small oligonucleotides are shown to undergo collisional and collision-free neutralization following matrix assisted laser desorption and ionization (MALDI). Using a modified MALDI time of flight instrument, approximate collisional cross sections and collision-free lifetimes have been measured for negative ions of 3-,4-, 6- and 7-mer oligonucleotides. Collisional cross sections were on the order of 10(-14) cm2, With collision-free lifetimes on the order of 10-100 mus. The evidence suggests that the collision-free lifetime may be decreasing with increasing biopolymer size. Implications of this neutralization process on MALDI-TOF experiments and TOF based DNA sequencing schemes are also discussed. RP JONES, RB (reprint author), OAK RIDGE NATL LAB,CHEM PHYS SECT,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831, USA. RI Allman, Steve/A-9121-2011; Tang, Kai/A-2194-2011 OI Allman, Steve/0000-0001-6538-7048; NR 12 TC 8 Z9 8 U1 1 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 SEP 17 PY 1993 VL 212 IS 5 BP 451 EP 457 DI 10.1016/0009-2614(93)87227-T PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX373 UT WOS:A1993LX37300005 ER PT J AU LOTT, JA SCHNEIDER, RP CHOQUETTE, KD KILCOYNE, SP FIGIEL, JJ AF LOTT, JA SCHNEIDER, RP CHOQUETTE, KD KILCOYNE, SP FIGIEL, JJ TI ROOM-TEMPERATURE CONTINUOUS-WAVE OPERATION OF RED VERTICAL-CAVITY SURFACE-EMITTING LASER-DIODES SO ELECTRONICS LETTERS LA English DT Article DE VERTICAL CAVITY SURFACE EMITTING LASERS; VISIBLE SEMICONDUCTOR LASERS AB The first room temperature (23-degrees-C) continuous wave visible vertical cavity surface emitting laser diodes are reported. Annular contact devices with a 5mum optical aperture in a 15mum diameter mesa emit at 670.4nm with a threshold current of 5mA at 2.4V. Devices with 20-60mum diameter mesas operate continuous wave below -13-degrees-C. C1 UNIV NEW MEXICO,CTR HIGH TECHNOL MAT,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,ALBUQUERQUE,NM 87131. RP LOTT, JA (reprint author), SANDIA NATL LABS,MICROELECTR & PHOTON,ALBUQUERQUE,NM 87185, USA. NR 9 TC 24 Z9 24 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 SEP 17 PY 1993 VL 29 IS 19 BP 1693 EP 1694 DI 10.1049/el:19931126 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA MG598 UT WOS:A1993MG59800015 ER PT J AU RICHTER, B AF RICHTER, B TI B-FACTORY PROPOSALS SO SCIENCE LA English DT Letter RP RICHTER, B (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 17 PY 1993 VL 261 IS 5128 BP 1505 EP 1505 DI 10.1126/science.261.5128.1505 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX474 UT WOS:A1993LX47400002 PM 17798095 ER PT J AU LLOYD, S AF LLOYD, S TI A POTENTIALLY REALIZABLE QUANTUM COMPUTER SO SCIENCE LA English DT Article ID TURING-MACHINES; COMPUTATION; SYSTEMS; REVERSIBILITY; DYNAMICS; ENERGY; MODELS; LOGIC AB Arrays of weakly coupled quantum systems might compute if subjected to a sequence of electromagnetic pulses of well-defined frequency and length. Such pulsed arrays are true quantum computers: Bits can be placed in superpositions of 0 and 1, logical operations take place coherently, and dissipation is required only for error correction. Operated with frequent error correction, such a system functions as a parallel digital computer. Operated in a quantum-mechanically coherent manner, such a device functions as a general-purpose quantum-mechanical micromanipulator, capable of both creating any desired quantum state of the array and transforming that state in any desired way. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87544. RP LLOYD, S (reprint author), LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,LOS ALAMOS,NM 87544, USA. NR 35 TC 413 Z9 416 U1 3 U2 26 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 17 PY 1993 VL 261 IS 5128 BP 1569 EP 1571 DI 10.1126/science.261.5128.1569 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX474 UT WOS:A1993LX47400027 PM 17798117 ER PT J AU NINOMIYA, S ITOH, K NISHIKAWA, M HOLROYD, R AF NINOMIYA, S ITOH, K NISHIKAWA, M HOLROYD, R TI EFFECT OF PRESSURE ON THE EQUILIBRIUM E- PLUS CO2 REVERSIBLE-ARROW CO2- IN 2-METHYLBUTANE AND 2,2-DIMETHYLBUTANE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON-AFFINITIES; NONPOLAR-SOLVENTS; LIQUIDS AB The reaction e- + CO2 reversible CO2- was studied in two alkane solvents for temperatures from 22 to 100-degrees-C and for pressures up to 3000 bar. The equilibrium constants and thermodynamic quantities for this reaction are reported from which the energies and entropies of solution of the electron in 2-methylbutane and 2,2-dimethylbutane are obtained. The free energy of reaction decreases as the solvent density increases. The significance of the volume changes for this reaction, which are between -190 and -300 CM3/Mol, is discussed. The entropy of reaction decreases largely due to the entropy of polarization of the solvent by CO2-. Mobilities of excess electrons in 2-methylbutane are also reported for temperatures from 23 to 100-degrees-C and for applied pressures from 1 to 2500 bar. The decrease in mobility with increasing pressure is attributed to increased probability of electron trapping at high pressure. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. UNIV TOKYO,DEPT PURE & APPL SCI,TOKYO 113,JAPAN. NR 14 TC 17 Z9 17 U1 1 U2 3 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 SEP 16 PY 1993 VL 97 IS 37 BP 9488 EP 9492 DI 10.1021/j100139a037 PG 5 WC Chemistry, Physical SC Chemistry GA LY472 UT WOS:A1993LY47200037 ER PT J AU RUSSELL, TP DELINE, VR DOZIER, WD FELCHER, GP AGRAWAL, G WOOL, RP MAYS, JW AF RUSSELL, TP DELINE, VR DOZIER, WD FELCHER, GP AGRAWAL, G WOOL, RP MAYS, JW TI DIRECT OBSERVATION OF REPTATION AT POLYMER INTERFACES SO NATURE LA English DT Article ID THEORETICAL-MODELS; RELAXATION; DYNAMICS; SYSTEMS; CHAIN; MELTS; DIFFUSION; SEGMENTS; KINETICS; MOTION AB ALTHOUGH the diffusion of polymer chains in the liquid state can be described over long distances by classical diffusion laws, chain entanglements make a description of the short-range behaviour more complex. In the standard 'reptation' model1,2 the polymer chains are considered to move in a curvilinear manner along their own contours, exhibiting snake-like motion through the entangled sea of surrounding molecules. This model successfully explains many observations3-13, yet no direct evidence for reptative motion has been reported. Here we describe the observation of reptation of molecules across the interface between two types of partially deuterated polystyrene polymers. The time evolution of the hydrogen and deuterium profiles, determined by dynamic secondary-ion mass spectrometry, can be explained only on the basis of a reptation model. Our results demonstrate that, despite being inevitably simplified, the description of polymer diffusion in terms of reptation is essentially correct. C1 ARGONNE NATL LAB, ARGONNE, IL 60439 USA. UNIV ILLINOIS, DEPT MAT SCI & ENGN, URBANA, IL 61801 USA. UNIV ALABAMA, DEPT CHEM, BIRMINGHAM, AL 35294 USA. RP IBM CORP, ALMADEN RES CTR, DIV RES, 650 HARRY RD, SAN JOSE, CA 95120 USA. NR 27 TC 65 Z9 65 U1 3 U2 22 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 SEP 16 PY 1993 VL 365 IS 6443 BP 235 EP 237 DI 10.1038/365235a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX471 UT WOS:A1993LX47100047 ER PT J AU SABOUNGI, ML FORTNER, J HOWELLS, WS PRICE, DL AF SABOUNGI, ML FORTNER, J HOWELLS, WS PRICE, DL TI DYNAMIC ENHANCEMENT OF CATION MIGRATION IN A ZINTL ALLOY BY POLYANION ROTATION SO NATURE LA English DT Article ID METAL LEAD ALLOYS; NEUTRON-SCATTERING; BETA-NASN; CSPB; KPB AB ZINTL alloys are compounds of an alkali metal A with a polyvalent metal M in which transfer of an electron from A to M leads to bonding behaviour in the M- ions typical of elements one column to the right in the Periodic Table. For example, ASn and APb contain tetrahedral M4(4-) polyanions in both the crystalline and liquid phases1 whereas AAl alloys crystallize in tetrahedrally bonded networks typical of Group IV' elements2. These bonding patterns also determine the character of the disorder in the solid at high temperature. We have recently identified a plastic crystal phase in CsPb just below the melting point, in which the Pb-4(4-) polyanions undergo jump reorientations3; LiAl, in contrast, is metallic, with mobile Li+ ions4. Here we report unusual disordering behaviour in the Zintl alloy NaSn, in which both types of dynamic disorder appear: rapid reorientations of the Sn-4(4-) polyanions enhance jump migration of the Na+ cations by means of a 'paddle-wheel' effect. The two types of disorder are strongly coupled, so that only one disordering transition takes place as the melting point is approached. C1 RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. RP SABOUNGI, ML (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 23 TC 28 Z9 29 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 16 PY 1993 VL 365 IS 6443 BP 237 EP 239 DI 10.1038/365237a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX471 UT WOS:A1993LX47100048 ER PT J AU FLEGAL, AR MARING, H NIEMEYER, S AF FLEGAL, AR MARING, H NIEMEYER, S TI ANTHROPOGENIC LEAD IN ANTARCTIC SEA-WATER SO NATURE LA English DT Article ID WEDDELL SEA; CONTAMINATION; POLLUTION; CADMIUM; COPPER; COLUMN; FLUXES; METALS; SOILS; SNOW AB ANTARCTICA is believed to be a relatively pristine continent, mainly because of its remote location and the atmospheric circulation patterns that limit the transport of industrial aerosols into the Antarctic polar cell1-4. This perception is apparently supported by the extremely low concentrations of lead in Antarctic surface waters-an observation that has been interpreted as showing insignificant contamination by anthropogenic lead5. The isotopic composition of lead in other natural waters has been used as a tracer of the sources of lead, and in particular to identify anthropogenic inputs6,7. Here we apply this approach to Antarctic surface waters, and show that despite the low concentrations of lead in these waters (which are confirmed by our measurements), their isotopic composition reveals a significant contribution of lead from industrial sources. The extremely low concentrations of lead in these waters appear to be due to biological scavenging of the lead during periods of intense primary production. C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,DIV MARINE & ATMOSPHER CHEM,MIAMI,FL 33149. LAWRENCE LIVERMORE NATL LAB,DIV NUCL CHEM,LIVERMORE,CA 94550. RP FLEGAL, AR (reprint author), UNIV CALIF SANTA CRUZ,EARTH SCI BOARD,SANTA CRUZ,CA 95064, USA. NR 26 TC 67 Z9 71 U1 4 U2 15 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 16 PY 1993 VL 365 IS 6443 BP 242 EP 244 DI 10.1038/365242a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX471 UT WOS:A1993LX47100050 ER PT J AU TANG, WK AF TANG, WK TI OBSERVATION OF HIGH-ENERGY QUARK-ANTIQUARK ELASTIC-SCATTERING WITH MESONIC EXCHANGE SO PHYSICS LETTERS B LA English DT Article ID QCD; ASYMPTOTICS; AMPLITUDES; HERA AB We studied the high energy quark-antiquark elastic scattering with an exchange of a mesonic state in the t channel with -t/LAMBDA(QCD)2 much greater than 1. Two methods are proposed to eliminate the strong background from bare pomeron, reggized gluon and odderon exchange. The feasibility of measuring mesonic reggeon exchange is discussed. RP TANG, WK (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 16 PY 1993 VL 314 IS 2 BP 233 EP 236 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LX048 UT WOS:A1993LX04800013 ER PT J AU ALVES, LC ALLEN, LA HOUK, RS AF ALVES, LC ALLEN, LA HOUK, RS TI MEASUREMENT OF VANADIUM, NICKEL, AND ARSENIC IN SEAWATER AND URINE REFERENCE MATERIALS BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITH CRYOGENIC DESOLVATION SO ANALYTICAL CHEMISTRY LA English DT Article ID POLYATOMIC ION INTERFERENCES; MIXED-GAS PLASMAS; ICP-MS; CHLORIDE INTERFERENCE; TRACE ANALYSIS; ARGON; REDUCTION; NITROGEN; OXIDE; PRECONCENTRATION AB Addition of a small dose (2%) of H-2 to the aerosol gas flow enhanced analyte signals by a factor of 2-3, which compensated for the loss of analyte signal that accompanied earlier efforts at cryogenic desolvation with inductively coupled plasma mass spectrometry (ICP-MS). Vanadium, nickel, and arsenic at microgram per liter levels in urine, river, and seawater reference materials were determined. The polyatomic ions ClO+, CaO+, and ArCl+, which normally cause severe overlap interferences for these elements, were attenuated to manageable levels by cryogenic desolvation. The samples were simply diluted with 1% HNO3 so that the chloride could be removed as HCl. The analytical results obtained for these standard reference materials agreed closely with the certified or recommended values. The detection limit ranges (3sigma) obtained were 10-1000 ng L-1 for V, 0.03-20 mug L-1 for Ni, and 4-7000 ng L-1 for As in the original samples. The samples were introduced by flow injection to minimize clogging of the sampling orifice. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RI Alves, Luis/J-9505-2013 OI Alves, Luis/0000-0001-5369-5019 NR 30 TC 53 Z9 53 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD SEP 15 PY 1993 VL 65 IS 18 BP 2468 EP 2471 DI 10.1021/ac00066a011 PG 4 WC Chemistry, Analytical SC Chemistry GA LX166 UT WOS:A1993LX16600012 PM 8238940 ER PT J AU DUCKWORTH, DC DONOHUE, DL SMITH, DH LEWIS, TA MARCUS, RK AF DUCKWORTH, DC DONOHUE, DL SMITH, DH LEWIS, TA MARCUS, RK TI DESIGN AND CHARACTERIZATION OF A RADIO-FREQUENCY-POWERED GLOW-DISCHARGE SOURCE FOR DOUBLE-FOCUSING MASS SPECTROMETERS SO ANALYTICAL CHEMISTRY LA English DT Article ID PLANAR SYSTEM; SOLIDS; PLASMA; EMISSION; ION AB A radio-frequency- (rf-) powered glow discharge has been interfaced to a double-focusing mass spectrometer. This type of discharge allows direct analysis of nonconducting, as well as conducting, solids. The rf discharge source and electrical system overcome several problems which have inhibited success in prior efforts. Problems of inadequate rf shielding, maintaining the necessary dc bias potential on the sample surface, preventing rf modulation of ion energies, and coupling of the accelerating potential to the discharge are resolved. Representative spectra of glass, soil, and brass matrices are presented. Preliminary relative sensitivity factors for conducting and non-conducting matrices show relatively small differences in ion yields across the periodic table. C1 OAK RIDGE NATL LAB,DIV INSTRUMENTAT & CONTROLS,OAK RIDGE,TN 37831. CLEMSON UNIV,DEPT CHEM,CLEMSON,SC 29634. RP DUCKWORTH, DC (reprint author), OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831, USA. RI Duckworth, Douglas/B-7171-2015 OI Duckworth, Douglas/0000-0002-8161-5685 NR 31 TC 49 Z9 49 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD SEP 15 PY 1993 VL 65 IS 18 BP 2478 EP 2484 DI 10.1021/ac00066a013 PG 7 WC Chemistry, Analytical SC Chemistry GA LX166 UT WOS:A1993LX16600014 ER PT J AU TANG, J NORRIS, JR AF TANG, J NORRIS, JR TI ON SUPEREXCHANGE ELECTRON-TRANSFER COUPLING FOR A 3-COMPONENT SYSTEM SO CHEMICAL PHYSICS LA English DT Article ID PRIMARY CHARGE-SEPARATION; NONSUPEREXCHANGE COHERENT MECHANISM; PHOTOSYNTHETIC REACTION CENTERS; BACTERIAL REACTION CENTERS; RHODOPSEUDOMONAS-SPHAEROIDES; POLAR-SOLVENTS; 3A RESOLUTION; DYNAMICS; SPECTROSCOPY; VIRIDIS AB The Zusman equation is applied to derive the effective matrix elements for superexchange and sequential electron transfer for a three-component system consisting of a donor, a distant acceptor, and a bridging intermediate. Analytical expressions can be derived for the special ''degenerate'' case of triple crossing where all three Marcus free-energy parabolas cross at the same point. For the nondegenerate case, where the direct vertical energy gap between the donor and the intermediate is large, one expects the same result as for second-order perturbation theory. RP TANG, J (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Tang, Jau/D-8382-2012 OI Tang, Jau/0000-0003-2078-1513 NR 37 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD SEP 15 PY 1993 VL 175 IS 2-3 BP 337 EP 342 DI 10.1016/0301-0104(93)85162-2 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX363 UT WOS:A1993LX36300011 ER PT J AU ZREDAGOSTYNSKA, G KYLE, PR FINNEGAN, DL AF ZREDAGOSTYNSKA, G KYLE, PR FINNEGAN, DL TI CHLORINE, FLUORINE, AND SULFUR EMISSIONS FROM MOUNT EREBUS, ANTARCTICA AND ESTIMATED CONTRIBUTIONS TO THE ANTARCTIC ATMOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOUTH-POLE; GASES; PARTICLES; COLLECTION; VOLCANOS; DIOXIDE; METALS AB The discharge rates of halogens in aerosols and gases emitted from Mount Erebus between December 1986 and January 1991 were estimated by combining element-to-sulfur ratios on filter samples with SO2 output measured by COSPEC. The halogen and sulfur content of the gas vary in a quasi-cyclical pattern possibly because of a heterogeneous distribution of volatiles in the Erebus magmatic system. The emission rates of HF and HCl have increased twofold since 1986 reaching 6 and 13.3 Gg yr-1, respectively, in 1991, making Erebus an important contributor of halogens to the Antarctic atmosphere. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP ZREDAGOSTYNSKA, G (reprint author), NEW MEXICO INST MIN & TECHNOL,DEPT GEOSCI,SOCORRO,NM 87801, USA. NR 21 TC 23 Z9 27 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD SEP 15 PY 1993 VL 20 IS 18 BP 1959 EP 1962 DI 10.1029/93GL01879 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LX651 UT WOS:A1993LX65100018 ER PT J AU BARNHART, DM CLARK, DL HUFFMAN, JC VINCENT, RL WATKIN, JG AF BARNHART, DM CLARK, DL HUFFMAN, JC VINCENT, RL WATKIN, JG TI ALIPHATIC NEODYMIUM ALKOXIDES WITH STERICALLY DEMANDING LIGANDS - PREPARATION AND X-RAY CRYSTAL-STRUCTURES OF ND2(OCH-I-PR2)6L2 (L = THF, PY) AND [ND2(OCH-I-PR2)6(MU-DME)]INFINITY SO INORGANIC CHEMISTRY LA English DT Article ID METAL MULTIPLE BONDS; MOLECULAR-STRUCTURE; SOLID-STATE; COMPLEXES; YTTRIUM; OXYGEN; LANTHANOIDS; REACTIVITY; ARYLOXIDES; CHEMISTRY AB Reaction of the neodymium tris(silylamide) Nd[N(SiMe3)2]3 with 3 equiv of diisopropylmethanol (HOCH-i-Pr2) in hexane in the presence of THF yields the dimeric Lewis base adduct Nd2(OCH-i-Pr2)6(THF)2 (1). The THF ligands are easily replaced with pyridine in hexane solvent at room temperature to yield the pyridine adduct Nd2(OCH-i-Pr2)6(py)2 (2). The Nd-O bridges in the dimeric alkoxide unit are found to be quite robust, and reaction of 1 with neat 1,2-dimethoxyethane (DME) at room temperature produces Nd2(OCH-i-Pr2)6(mu-DME) (3), in which the two oxygen atoms of each DME molecule link adjacent Nd2(OCH-i-Pr2)6 units to form an infinite-chain structure. In the solid-state structures of 1-3, each Nd atom adopts a distorted trigonal bipyramidal geometry, in which the Nd2O6L2 core can be viewed as two NdO4L trigonal bipyramids joined along a common axial-equatorial edge with the neutral donor ligand L (THF, py, or 1/2 DME) occupying an axial position. The terminal Nd-O distances of OR ligands average 2.153(4), 2.146(4), and 2.145(6) angstrom, while bridging Nd-O distances average 2.381(4), 2.383(9), and 2.375(9) angstrom for 1-3, respectively. The Nd-O-C angles of the terminal alkoxides are very obtuse and average 164.9(4), 174.9(4), and 171.8(8)-degrees, respectively. The Nd-O distances to the oxygen atom of the neutral THF and DME ligands are 2.552(5) and 2.604(6) angstrom, while the Nd-N distance for coordinated pyridine is 2.682(5) angstrom. Crystal data for 1 at -161-degrees-C: monoclinic space group P2(1)/n, a = 10.949(1) angstrom, b = 21.433(3) angstrom, c = 11.965(1) angstrom, beta = 95.63(1)-degrees, V = 2794.44 angstrom3, d(calc) = 1.336 g cm-3, Z = 2. Crystal data for 2 at -162-degrees-C: triclinic space group P1BAR, a = 12.003(4) angstrom, b = 12.243(4) angstrom, c = 11.454(4) angstrom, alpha = 109.99(1)-degrees, beta = 108.82(1)-degrees, gamma = 98.76(1)-degrees, V = 1430.47 angstrom3, d(calc) = 1.321 g cm-3, Z = 1. Crystal data for 3 at -40-degrees-C: triclinic space group P1BAR, a = 10.797(3) angstrom, b = 10.984(3) angstrom, c = 12.112(3) angstrom, alpha = 109.08(3)-degrees, beta = 100.32(2)-degrees, gamma = 90.80(2)-degrees, V = 1331.5 angstrom3, d(calc) = 1.334 g cm-3, Z = 1. C1 INDIANA UNIV,CTR MOLEC STRUCT,DEPT CHEM,BLOOMINGTON,IN 47405. RP CLARK, DL (reprint author), LOS ALAMOS NATL LAB,INORGAN & STRUCT CHEM LAB,INC 1,LOS ALAMOS,NM 87545, USA. RI Clark, David/A-9729-2011 NR 53 TC 46 Z9 46 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD SEP 15 PY 1993 VL 32 IS 19 BP 4077 EP 4083 DI 10.1021/ic00071a018 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LY531 UT WOS:A1993LY53100018 ER PT J AU SMITH, DP KOHEN, E MAESTRE, MF FISH, RH AF SMITH, DP KOHEN, E MAESTRE, MF FISH, RH TI BIOORGANOMETALLIC CHEMISTRY .3. ROLE OF THE PHOSPHATE GROUP DURING REACTIONS OF ADENOSINE-MONOPHOSPHATE DERIVATIVES WITH AN (ETA-5-PENTAMETHYLCYCLOPENTADIENYL)RHODIUM AQUA COMPLEX IN THE DIASTEREOSELECTIVE FORMATION OF CYCLIC TRIMERS, [CP-ASTERISK-RH(AMP)]3 SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR MECHANICS CALCULATIONS; AQUEOUS COORDINATION CHEMISTRY; METALLOCENE ANTITUMOR AGENTS; ALPHA-PO4 CHELATION; CRYSTAL-STRUCTURE; NMR EVIDENCE; DNA; V(ETA-5-C5H5)2CL2; 5'-NUCLEOTIDE; DICHLORIDE AB The reactions of adenosine 5'-monophosphate (5'-AMP) in water (pH 5-8) with a (eta5-pentamethylcyclopentadienyl)rhodium aqua complex, [Cp*Rh(H2O)2(OTf)2]x (1), showed, by H-1 and P-31 NMR spectroscopy, that the 5'-P(O)2=O group significantly inhibited cyclic trimer formation, [Cp*Rh(mu-eta1(N1):eta2(N6,N7)-5'-AMP)]3, via competition with Nl and NH6 for the Cp*Rh site and, as well, provided other mononuclear and dinuclear Cp*Rh-O-P complexes. In contrast, both the phosphate methyl ester of 5'-AMP and 3'-AMP exclusively formed the cyclic trimer structures [Cp*Rh(mu-eta1(N1):eta2(N6,N7)-methyl-5'-/3'-AMP)]3. The consequence of steric effects, as demonstrated-by the position and substitution of the phosphate group attached to the ribose, on the diastereoselectivity of cyclic trimer formation, as observed by H-1 and P-31 NMR spectroscopy and circular dichroism analysis over time, shows that the phosphate methyl ester of 5'-AMP provides a greater diastereoselectivity (6:1) after 1 week of equilibration compared to 5'-AMP (1.5:1) and 3'-AMP (1.2:1). C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 28 TC 45 Z9 45 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 SEP 15 PY 1993 VL 32 IS 19 BP 4119 EP 4122 DI 10.1021/ic00071a026 PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LY531 UT WOS:A1993LY53100026 ER PT J AU FLEIG, PF VANDERSLUYS, WG BERG, JM AF FLEIG, PF VANDERSLUYS, WG BERG, JM TI SYNTHESIS AND CHARACTERIZATION OF ION SEPARATED MU2(OBU(T))9 SPECIES WHERE M=NBU(N)(4), PPH4, PH3PME AND K-DIBENZO-18-CROWN-6 SO INORGANICA CHIMICA ACTA LA English DT Note ID ALKOXIDE CHEMISTRY AB Reaction of the molecular species KU2(OBu(t))9 with bromide salts of non-coordinating counter-cations, MBr (M = NBu(n)4, PPh4 and Ph3PMe) in THF solution results in the precipitation of KBr and the formation of the ion separated MU2(OBu(t))9 salts. The potassium cation can also be removed from the coordination sphere of the dinuclear uranium anion by reaction with dibenzo-18-crown-6 ether in THF. These compounds have been characterized by H-1 NMR and electronic absorption spectroscopy. H-1 NMR indicates that the dinuclear face-shared bioctahedral structure of the U2(OBu(t))9 anion is retained in the ion separated species. Comparison of the electronic absorption spectra of KU2(OBu(t))9 with the dinuclear U2(OBu(t))9 anion in solution also supports this conclusion. C1 UNIV MONTANA,DEPT CHEM,MISSOULA,MT 59812. LOS ALAMOS NATL LAB,DIV NUCL MAT TECHNOL,LOS ALAMOS,NM 87545. NR 14 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD SEP 15 PY 1993 VL 211 IS 2 BP 243 EP 246 DI 10.1016/S0020-1693(00)85609-1 PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA MB333 UT WOS:A1993MB33300020 ER PT J AU SHIGESATO, Y PAINE, DC HAYNES, TE AF SHIGESATO, Y PAINE, DC HAYNES, TE TI LATTICE-DEFECTS IN O+ IMPLANTED TIN-DOPED INDIUM OXIDE-FILMS SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE TIN-DOPED INDIUM OXIDE; ITO; ION IMPLANTATION; LATTICE DEFECT; NEUTRAL SCATTERING CENTER; CHARGED SCATTERING CENTER; TRANSMITTANCE; ELECTRICAL PROPERTIES; HALL EFFECT MEASUREMENT; TRANSMISSION ELECTRON MICROSCOPY; MICROSTRUCTURE ID ELECTRICAL-PROPERTIES AB In this work we use transmission electron microscopy to identify extended lattice defects which result from O+ ion implantation at a dose of 1.3 x 10(15)/cm2 into S n-doped In2O3 at room temperature. Measurement of the resistivity, mobility, carrier density, and transmissivity to visible light as a function of implant dose (0 to 1.3 x 10(15)/cm2) reveals that increasing dose results in a degradation in electronic and optical properties of ITO. Analysis of these results using charged and neutral scattering models reveals that the observed changes in electronic and optical properties may be due to the generation of neutral scattering centers. Transmission electron microscopy analysis of heavily O+ implanted films reveals the presence of intragranular regions of isolated strain contrast indicating lattice damage which may be associated with these neutral scatter centers. C1 BROWN UNIV,DIV ENGN,PROVIDENCE,RI 02912. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Haynes, Tony/P-8932-2015 OI Haynes, Tony/0000-0003-2871-4745 NR 20 TC 24 Z9 24 U1 0 U2 3 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD SEP 15 PY 1993 VL 32 IS 9B BP L1352 EP L1355 PG 4 WC Physics, Applied SC Physics GA LZ498 UT WOS:A1993LZ49800018 ER PT J AU DENDOOVEN, PG DRAKE, RP CABLE, MD AF DENDOOVEN, PG DRAKE, RP CABLE, MD TI GAMMA-RAY DIAGNOSTICS OF ALPHA-SLOWING IN INERTIAL CONFINEMENT FUSION-TARGETS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID NEUTRON SPECTROSCOPY; NUCLEAR TECHNIQUES; BRANCHING RATIO; PARTICLES; PLASMA; LANSA; ARRAY AB For large inertial confinement fusion deuterium-tritium targets, a way to diagnose alpha slowing might be via capture reaction gamma rays. Calculations are presented for two such methods: one uses the alpha+T direct capture gamma rays, the other is based on a series of resonant alpha-capture reactions. For small targets (rhoR less-than-or-equal-to 0.02 g/cm2), the total alpha+T gamma-ray yield relative to the DT neutron yield is temperature independent and proportional to the rhoR value. For large targets (rhoR greater-than-or-equal-to 0.2 g/cm2), this quantity becomes temperature dependent and rhoR independent. Some experimental aspects are discussed. C1 UNIV CALIF DAVIS,LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP DENDOOVEN, PG (reprint author), LAWRENCE LIVERMORE NATL LAB,PLASMA PHYS RES INST,POB 5508,LIVERMORE,CA 94550, USA. RI Drake, R Paul/I-9218-2012; OI Drake, R Paul/0000-0002-5450-9844; Dendooven, Peter/0000-0003-1859-1315 NR 26 TC 1 Z9 1 U1 0 U2 2 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 SEP 15 PY 1993 VL 74 IS 6 BP 3638 EP 3644 DI 10.1063/1.354504 PG 7 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800002 ER PT J AU HEBNER, GA HAYS, GN AF HEBNER, GA HAYS, GN TI LASER EFFICIENCY AND GAIN OF THE 1.73-MU-M ATOMIC XENON LASER AT HIGH HE/AR BUFFER GAS RATIOS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID AR-XE LASER; ELECTRON-BEAM; ELECTROIONIZATION LASER; RATE CONSTANTS; XE(6P) STATES; RARE-GASES; NUCLEAR; DEACTIVATION; PERFORMANCE; HE-3-XE AB Addition of helium to an Ar/Xe gas mixture has been shown to significantly improve the fission-fragment excited 1.73 mum atomic xenon laser performance. Using narrow band dielectric laser cavity mirrors to suppress the 2.03 mum atomic xenon transition, the 1.73 mum laser power efficiency varied between 1% and 3% for total pressures of 520-1550 Torr, He/Ar ratios of 3/1-16/1, and pump rates of 5-40 W/cm3. For a constant energy loading, the FWHM of the laser pulse with respect to the pump pulse increased by a factor of 2.5 when argon was replaced by helium. Small signal gain varied between 0.1%/cm and 1.0%/cm. The implication of helium substitution on the Ar/Xe laser kinetics is discussed. RP HEBNER, GA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 49 TC 8 Z9 9 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 SEP 15 PY 1993 VL 74 IS 6 BP 3673 EP 3679 DI 10.1063/1.354509 PG 7 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800007 ER PT J AU CASPERSON, DE COBBLE, JA FULTON, RD KYRALA, GA SCHAPPERT, GT TAYLOR, AJ WAHLIN, E AF CASPERSON, DE COBBLE, JA FULTON, RD KYRALA, GA SCHAPPERT, GT TAYLOR, AJ WAHLIN, E TI THIN FOIL X-RAY CONVERTERS PUMPED BY SUBPICOSECOND EXCIMER LASERS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIGH-IRRADIANCE; TARGETS; SYSTEM AB We have measured the conversion efficiency, as well as the spectral and temporal x-ray output of H- and He-like carbon line emission, from a thin foil of polypropylene that has been irradiated with subpicosecond KrF laser pulses. The effect of amplified spontaneous emission prepulse on the x-ray conversion process, as well as the application of these x-ray ''flashlamps'' toward pumping soft x-ray lasers, is discussed. RP CASPERSON, DE (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 14 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1993 VL 74 IS 6 BP 3707 EP 3711 DI 10.1063/1.354517 PG 5 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800013 ER PT J AU SUNIL, D SOKOLOV, J RAFAILOVICH, MH KOTYUZHANSKII, B GAFNEY, HD WILKENS, BJ HANSON, AL AF SUNIL, D SOKOLOV, J RAFAILOVICH, MH KOTYUZHANSKII, B GAFNEY, HD WILKENS, BJ HANSON, AL TI MICROSTRUCTURE OF PHOTODEPOSITED FE IN POROUS VYCOR GLASS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MOSSBAUER-SPECTROSCOPY; MAGNETIC-PROPERTIES; IRON; EXAFS AB The products derived from the UV photolysis of Fe(CO)5 physisorbed onto porous Vycor glass have been examined by x-ray microprobe analysis, Mossbauer spectroscopy, and extended x-ray absorption fine structure spectroscopy (EXAFS). Although the photolysis and subsequent heatings are carried out in air, spectroscopic data reveal two surprisingly different forms of iron. Isomer shift, pre-edge, and EXAFS data indicate that one product is similar to alpha-Fe2O3 and consists of an Fe3+ ion octahedrally surrounded by six oxygen atoms at a distance of 1.8 angstrom. Isomer shift, EXAFS, and pre-edge feature analysis show that the second compound, which comprises approximately 50% of the reaction product, is mainly elemental iron, in which a central Fe atom is surrounded by approximately eight other Fe atoms at a distance of 2 angstrom. X-ray microprobe analysis shows that aggregation occurs during photolysis due to the diffusion of Fe(CO)5 from the interior into exterior photodepleted volumes of glass. Heating has little effect on product ratio or distribution, but consolidating the glass at 1200-degrees-C leads to further aggregation and formation of magnetically ordered particles that exhibit magnetic hyperfine fields of 370 and 425 kG. C1 BELLCORE,RED BANK,NJ 07701. CUNY QUEENS COLL,DEPT CHEM,FLUSHING,NY 11367. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP SUNIL, D (reprint author), CUNY QUEENS COLL,DEPT PHYS,FLUSHING,NY 11367, USA. NR 30 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1993 VL 74 IS 6 BP 3768 EP 3777 DI 10.1063/1.354468 PG 10 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800020 ER PT J AU STEINBERG, DJ AF STEINBERG, DJ TI A RATE-DEPENDENT CONSTITUTIVE MODEL FOR MOLYBDENUM SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID STRAIN RATE; TEMPERATURE AB The Steinberg-Guinan-Lund rate-dependent constitutive model has been successfully applied to molybdenum [D. J. Steinberg and C. M. Lund, J. Appl. Phys. 65, 1528 (1989)]. The model reproduces yield strength versus strain rate and temperature data and also successfully simulates rate-dependent phenomena, such as shock-smearing, precursor decay, and precursor on reshock, as observed in one-dimensional gas gun experiments. The spall strength of molybdenum was determined to be 1.5 GPa. RP STEINBERG, DJ (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 17 TC 7 Z9 9 U1 0 U2 2 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 SEP 15 PY 1993 VL 74 IS 6 BP 3827 EP 3831 DI 10.1063/1.355316 PG 5 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800030 ER PT J AU WARREN, WL KANICKI, J ROBERTSON, J POINDEXTER, EH MCWHORTER, PJ AF WARREN, WL KANICKI, J ROBERTSON, J POINDEXTER, EH MCWHORTER, PJ TI ELECTRON-PARAMAGNETIC-RESONANCE INVESTIGATION OF CHARGE TRAPPING CENTERS IN AMORPHOUS-SILICON NITRIDE FILMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INDUCED METASTABLE DEFECTS; NITROGEN DANGLING-BOND; CORRELATION-ENERGY; THIN-FILMS; STATES; SEMICONDUCTORS; TRANSISTORS; TRAPS; MODEL; SIO2 AB We have explored the nature of the silicon dangling-bond center in amorphous hydrogenated silicon nitride (a-SiN(x):H) thin films, and its relationship to the charge trapping centers using electron paramagnetic resonance (EPR) and capacitance-voltage (C-V) measurements. We have investigated the quantitative relationship between the concentration of silicon dangling bonds using EPR and the concentration of charge traps, measured by C-V measurements, for both UV-illuminated and unilluminated a-SiN(x):H thin films subjected to both electron and hole injection sequences. A theoretical framework for our results is also discussed. These results continue to support a model in which the Si dangling bond is a negative-U defect in silicon nitride, and that a change in charge state of preexisting positively and negatively charged Si sites is responsible for the trapping phenomena observed in these thin film dielectrics. C1 IBM CORP,THOMAS J WATSON RES CTR,DIV RES,YORKTOWN HTS,NY 10598. NATL POWER LABS,LEATHERHEAD KT22 7SE,SURREY,ENGLAND. USA,RES LAB,ELECTR & POWER SOURCES DIRECTORATE,FT MONMOUTH,NJ 07703. SANDIA NATL LABS,DEPT SILICON TECHNOL,ALBUQUERQUE,NM 87185. RP WARREN, WL (reprint author), SANDIA NATL LABS,ADV MAT LAB,ALBUQUERQUE,NM 87106, USA. RI Kanicki, Jerzy/E-2753-2016 OI Kanicki, Jerzy/0000-0002-3649-8360 NR 55 TC 74 Z9 75 U1 3 U2 11 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 SEP 15 PY 1993 VL 74 IS 6 BP 4034 EP 4046 DI 10.1063/1.355315 PG 13 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800060 ER PT J AU WANG, YL WIESMANN, HJ LIU, CF ZHU, Y SABATINI, RL SUENAGA, M AF WANG, YL WIESMANN, HJ LIU, CF ZHU, Y SABATINI, RL SUENAGA, M TI FABRICATION AND PROPERTIES OF TEXTURED YBA2CU3O7 THICK-FILMS ON POLYCRYSTALLINE AG0.9PD0.1 AND SILVER SUBSTRATES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CRITICAL CURRENT-DENSITY; SPRAY PYROLYSIS; SUPERCONDUCTING PROPERTIES; DEPOSITION TECHNIQUE; YBCO FILMS; MICROSTRUCTURE; GROWTH; ALLOYS; MECHANISM; OXIDES AB Highly textured (c axis perpendicular to the plane of the substrate tape) thick films of YBa2Cu3O7 grown on Ag0.9Pd0.1 and pure silver substrates have been made by a traveling heated zone method. The speed of the traveling zone can be as fast as approximately 5 cm/h and the temperatures of the zone, 930-975-degrees-C, were well below the peritectic temperature of YBa2Cu3O7. A precursor layer, which consisted of a nitrate solution of yttrium, barium, and copper cations, was deposited by spray pyrolysis directly onto a heated substrate. The values of the resistively measured T(c) were 83-91 K. The transport critical current density of these thick films was in the range of 2-8 X 10(3) A/cm2 at 77 K and 0 T. RP WANG, YL (reprint author), BROOKHAVEN NATL LAB,DIV MAT SCI,UPTON,NY 11973, USA. NR 45 TC 4 Z9 5 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 SEP 15 PY 1993 VL 74 IS 6 BP 4052 EP 4059 DI 10.1063/1.354449 PG 8 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800062 ER PT J AU KURTZ, SR AF KURTZ, SR TI ANOMALOUS ELECTROREFLECTANCE SPECTRUM OF SPONTANEOUSLY ORDERED GA0.5IN0.5P SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID VAPOR-PHASE EPITAXY; BAND-GAP ENERGY; III-V ALLOYS; GROWTH TEMPERATURE; PHOTOLUMINESCENCE; GA0.52IN0.48P; GAINP; SEMICONDUCTORS; DEPENDENCE AB The electroreflectance spectrum of spontaneously ordered Ga0.5In0.5P contains two extra features at energies near 2.2 and 2.35 eV. The energies and intensities of these transitions are shown to be dependent on growth temperature and substrate misorientation. The possible origins of the two transitions are explored. The analysis shows that the transition at about 2.35 eV exhibits shifts consistent with those expected for Ga0.5In0.5P with ordered {111} planes. The second transition is shown to be unexpected and is not conclusively assigned. However, a possible assignment is identified, implying that a complete understanding of spontaneously ordered Ga0.5In0.5P may require simultaneous consideration of two different types of order. RP KURTZ, SR (reprint author), NATL RENEWABLE ENERGY LAB, 1617 COLE BLVD, GOLDEN, CO 80401 USA. NR 34 TC 29 Z9 30 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1993 VL 74 IS 6 BP 4130 EP 4135 DI 10.1063/1.354437 PG 6 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800074 ER PT J AU ANDERS, S ANDERS, A BROWN, I AF ANDERS, S ANDERS, A BROWN, I TI MACROPARTICLE-FREE THIN-FILMS PRODUCED BY AN EFFICIENT VACUUM-ARC DEPOSITION TECHNIQUE SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID EVAPORATION AB Macroparticle-free films of various metals and diamond-like carbon have been obtained by a pulsed vacuum arc deposition technique. An axial magnetic field (100-200 mT) generated by the discharge current itself was used to focus the plasma produced by the cathode spots and to guide the plasma flow through a macroparticle filter. The films were characterized by scanning electron microscopy, atomic force microscopy, and Rutherford backscattering spectrometry. They were found to be macroparticle-free. The total efficiency of the combined gun-filter plasma source is even higher than a standard nonfiltered vacuum arc plasma source in terms of deposited film thickness per discharge, because the plasma losses in the filter are overcompensated by the focused plasma injection into the filter. RP LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RI Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016 OI Anders, Andre/0000-0002-5313-6505; NR 12 TC 81 Z9 86 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1993 VL 74 IS 6 BP 4239 EP 4241 DI 10.1063/1.354431 PG 3 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800093 ER PT J AU VERGHESE, S RICHARDS, PL SACHTJEN, SA CHAR, K AF VERGHESE, S RICHARDS, PL SACHTJEN, SA CHAR, K TI SENSITIVE BOLOMETERS USING HIGH-T(C) SUPERCONDUCTING THERMOMETERS FOR WAVELENGTHS 20-30-MU-M SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID FEASIBILITY; FABRICATION AB Two types of sensitive high-T(c) bolometer have been fabricated on 20-mum-thick sapphire substrates with YBa2Cu3O7-delta thin film transition edge thermometers. The sensitivity of both devices is superior to commercially available, room temperature pyroelectric detectors. A 1 X 1 mm bolometer with a radiation absorber of gold black smoke has a noise equivalent power NEP=2.4 X 10(-11) W/Hz1/2 at 10 Hz and has useful sensitivity over wavelengths 20-100 mum. A 3 X 3 mm bolometer with a Bi film radiation absorber has NEP=3.6 X 10(-10) W/Hz1/2 at 10 Hz and has useful sensitivity over wavelengths 100-300 mum. Water vapor transmittance spectra were measured to demonstrate the sensitivity of both devices. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP VERGHESE, S (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 14 TC 22 Z9 22 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 SEP 15 PY 1993 VL 74 IS 6 BP 4251 EP 4253 DI 10.1063/1.354435 PG 3 WC Physics, Applied SC Physics GA LY328 UT WOS:A1993LY32800097 ER PT J AU ROESSLER, PG OHLROGGE, JB AF ROESSLER, PG OHLROGGE, JB TI CLONING AND CHARACTERIZATION OF THE GENE THAT ENCODES ACETYL-COENZYME-A CARBOXYLASE IN THE ALGA CYCLOTELLA-CRYPTICA SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID FATTY-ACID BIOSYNTHESIS; COA CARBOXYLASE; ESCHERICHIA-COLI; SILICON DEFICIENCY; MESSENGER-RNA; PURIFICATION; PROTEINS; SEQUENCE; SUBUNIT; DNA AB The gene that encodes acetyl-coenzyme A carboxylase (ACCase; EC 6.4.1.2) in the eukaryotic alga Cyclotella cryptica has been isolated and cloned, representing the first time that a full-length gene for this enzyme has been isolated from a photosynthetic organism. The gene contains a 447-base pair intron that is located near the putative translation initiation codon and a 73-base pair intron that is located slightly upstream from the region that encodes the biotin binding site of the enzyme. The gene encodes a polypeptide that is predicted to be composed of 2089 amino acids and to have a molecular mass of 230 kDa. The deduced amino acid sequence exhibits strong similarity to the sequences of animal and yeast ACCases in the biotin carboxylase and carboxyltransferase domains. There is less sequence similarity in the biotin carboxyl carrier protein domain, although the highly conserved Met-Lys-Met of the biotin binding site is present. The amino terminus of the predicted ACCase sequence has characteristics of a signal sequence, suggesting that the enzyme is imported into chloroplasts via the endoplasmic reticulum, as has been shown to be the case for certain nuclear-encoded proteins that are transported into the chloroplasts of the diatom Phaeodactylum tricornutum. Southern blot analyses suggest that a single copy of this gene is present in C. cryptica. C1 MICHIGAN STATE UNIV,DEPT BOT & PLANT PATHOL,E LANSING,MI 48824. RP ROESSLER, PG (reprint author), NATL RENEWABLE ENERGY LAB,APPL BIOL SCI BRANCH,GOLDEN,CO 80401, USA. NR 40 TC 67 Z9 78 U1 3 U2 9 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 SEP 15 PY 1993 VL 268 IS 26 BP 19254 EP 19259 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA LW819 UT WOS:A1993LW81900019 PM 8103514 ER PT J AU GRAY, JA FARROW, RL DURANT, JL THORNE, LR AF GRAY, JA FARROW, RL DURANT, JL THORNE, LR TI THE ELECTRIC-DIPOLE MOMENT OF NO A2-SIGMA+ V'=0 MEASURED USING STARK QUANTUM-BEAT SPECTROSCOPY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPECTRUM; STATE; RESONANCE; MOLECULES; ATOMS AB We report measurements and analysis of Stark quantum beats observed in the fluorescence of nitric oxide (NO) from which we determine the electric dipole moment of the A 2SIGMA+ v' = 0 state. A pulse-amplified cw dye laser was used to excite the A-X (0,0) Q1(1) transition of (NO)-N-14-O-16 in electric fields up to 22.5 kV/cm. Fourier analysis of the time-resolved laser-induced fluorescence signals yielded Stark tunings for each of the six \M(F)\ hyperfine sublevels in the N = 1, J = 3/2 spin-rotational level. The measurements were fit to a model Hamiltonian including fine, hyperfine, and Stark matrix elements. The resulting dipole moment was then corrected for polarizability effects to yield a value for the A 2SIGMA+ v' = 0 state of mu(A) = 1.08 +/- 0.04 D. This result compares favorably to a previous measurement of mu(A) in v' = 3 and to our quantum theoretical calculations of the A 2SIGMA+ v' = 0 state reported here. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. NR 30 TC 28 Z9 28 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 SEP 15 PY 1993 VL 99 IS 6 BP 4327 EP 4333 DI 10.1063/1.466086 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX143 UT WOS:A1993LX14300008 ER PT J AU NORTH, SW LONGFELLOW, CA LEE, YT AF NORTH, SW LONGFELLOW, CA LEE, YT TI THE NEAR-ULTRAVIOLET PHOTODISSOCIATION DYNAMICS OF AZOMETHANE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 193 NM; ENERGY-DISTRIBUTION; AZOALKANES; PHOTOCHEMISTRY; THERMOCHEMISTRY; DECOMPOSITION; DISSOCIATION; FORMALDEHYDE; RADICALS; STEPWISE AB The photodissociation of azomethane following absorption of a single 351 nm photon was studied using the method of molecular beam photofragment translational spectroscopy. The dissociation was observed to proceed via cleavage of both C-N bonds to yield N2 and two methyl radicals. The measured time-of-flight spectra show evidence that the two methyl radicals possess unequal velocities in the azomethane center of mass suggesting that the dissociation is not symmetric. The angles between the asymptotic center-of-mass velocities for all three fragments are strongly correlated, implying that the methyldiazenyl radical (CH3N2) intermediate decomposes within a fraction of its rotational period. We conclude, therefore, that the dissociation is concerted, not stepwise as was inferred from recent time-resolved experiments. The overall translational energy distributions for all the photofragments in the azomethane center of mass reveal that an average of 60% of the total available energy appears as translation. A possible mechanism, consistent with the experimental findings, will be proposed and discussed. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP NORTH, SW (reprint author), LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720, USA. RI Lee, Yuan-Tseh/F-7914-2012; North, Simon/G-5054-2012 OI North, Simon/0000-0002-0795-796X NR 56 TC 51 Z9 51 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 SEP 15 PY 1993 VL 99 IS 6 BP 4423 EP 4429 DI 10.1063/1.466095 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX143 UT WOS:A1993LX14300017 ER PT J AU CLARY, DC SCHATZ, GC AF CLARY, DC SCHATZ, GC TI QUANTUM AND QUASI-CLASSICAL CALCULATIONS ON THE OH+CO-]CO2+H REACTION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CHEMICAL-REACTIONS; H-ATOMS; SCATTERING; OH; CO; H-2+CN->H+HCN; OH+H-2->H2O+H; DISTRIBUTIONS; TEMPERATURE; EXCITATION AB Scattering calculations on the OH + CO - CO2 + H reaction are reported using both quantum and quasiclassical methods. The rotating bond approximation is used in the quantum calculations. This method explicitly treats the OH vibration and CO rotation in the reactants and the bending vibration and a local CO stretch in the CO2 product. Analogous quasiclassical trajectory computations are also reported. A potential energy surface obtained as a fit to ab initio data is used. The quantum reaction probabilities are dominated by sharp resonances corresponding to vibrationally excited states of the HOCO complex formed in the reaction. The quantum and quasiclassical lifetimes of these resonances compare quite well with measurements made by Wittig et al. Calculations of differential cross sections, rate coefficients, and CO2 vibrational product distributions are also compared with experimental data. The comparisons of quantum and quasiclassical calculations for models that treat explicitly different numbers of degrees of freedom provide detailed insight into the dynamics of the OH + CO reaction. C1 NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. ARGONNE NATL LAB,THEORET CHEM GRP,ARGONNE,IL 60439. RP CLARY, DC (reprint author), UNIV CAMBRIDGE,DEPT CHEM,LENSFIELD RD,CAMBRIDGE CB2 1EW,ENGLAND. NR 57 TC 107 Z9 107 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 SEP 15 PY 1993 VL 99 IS 6 BP 4578 EP 4589 DI 10.1063/1.466057 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX143 UT WOS:A1993LX14300033 ER PT J AU MOALEM, M BALOOCH, M HAMZA, AV SIEKHAUS, WJ OLANDER, DR AF MOALEM, M BALOOCH, M HAMZA, AV SIEKHAUS, WJ OLANDER, DR TI SURFACE MOBILITY OF C-60 ON SIO2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article AB The interaction of a collisionless beam of thermal C60 nanoclusters with a silicon dioxide surface has been investigated with modulated molecular beam-mass spectroscopic techniques. Analysis of the amplitude and phase lag of the desorbed C60 shows the interaction mechanism to involve the elementary steps of sticking, desorption, and long-range surface diffusion. Surface diffusion coefficients determined in this measurement indicate that surface C60 nanoclusters approach two-dimensional gas-like behavior. The sticking probability of C60 clusters on SiO2 is determined to be unity. The best fit desorption rate constant k(d) for C60 from SiO2 is 5 x 10(10) exp(-23 kcal/mol/RT) in agreement with previous temperature programmed desorption experiments. The efficiencies of electron impact ionization of C60 to C60+ and C60++ is measured for electron energies from 10 to 105 eV for neutrals at 875 K. C1 LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94551. UNIV CALIF BERKELEY,DEPT NUCL ENGN,BERKELEY,CA 94720. NR 12 TC 16 Z9 16 U1 1 U2 3 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 SEP 15 PY 1993 VL 99 IS 6 BP 4855 EP 4859 DI 10.1063/1.466032 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LX143 UT WOS:A1993LX14300059 ER PT J AU SMALLEY, JF GENG, L FELDBERG, SW ROGERS, LC LEDDY, J AF SMALLEY, JF GENG, L FELDBERG, SW ROGERS, LC LEDDY, J TI EVIDENCE FOR ADSORPTION OF FE(CN)63-/4- ON GOLD USING THE INDIRECT LASER-INDUCED TEMPERATURE-JUMP METHOD SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article ID PERCHLORIC-ACID SOLUTIONS; DOUBLE-LAYER PROPERTIES; ELECTRODES; RELAXATION; DEPENDENCE; CHARGE; FILMS; FACES AB The addition of K3Fe(CN)6 and K4Fe(CN)6 to a 1 M KF solution is shown to effect a significant change in the response of the open-circuit potential to a rapid change in the interfacial temperature. Using the indirect laser-induced temperature-jump (ILIT) method the interfacial temperature can be changed in a few nanoseconds-fast enough so that electron transfer between the electrode and Fe(CN)63-/4- (adsorbed or in the bulk) does not have time to occur. The only explanation for a change in the ILIT response is that the Fe(CN)63-/4- adsorbs on the gold surface and effects a change in the structure, and therefore the thermal response, of the double layer. C1 BROOKHAVEN NATL LAB,DIV INSTRUMENTAT,UPTON,NY 11973. UNIV IOWA,DEPT CHEM,IOWA CITY,IA 52242. RP SMALLEY, JF (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV CHEM SCI,UPTON,NY 11973, USA. NR 27 TC 41 Z9 41 U1 1 U2 15 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD SEP 15 PY 1993 VL 356 IS 1-2 BP 181 EP 200 DI 10.1016/0022-0728(93)80520-R PG 20 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA LW120 UT WOS:A1993LW12000015 ER PT J AU RUSSELL, AE WILLIAMS, GP LIN, AS OGRADY, WE AF RUSSELL, AE WILLIAMS, GP LIN, AS OGRADY, WE TI FAR-INFRARED SYNCHROTRON-RADIATION FOR IN-SITU STUDIES OF THE ELECTROCHEMICAL INTERFACE SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Note ID ENHANCED RAMAN-SPECTROSCOPY; VIBRATIONAL FREQUENCIES; ELECTRODES; SILVER; IONS; ADSORPTION; REDUCTION; SURFACES; PYRIDINE; LAYER C1 BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973. GEORGE WASHINGTON UNIV,DEPT CHEM,WASHINGTON,DC 20052. USN,RES LAB,WASHINGTON,DC 20375. RP RUSSELL, AE (reprint author), UNIV LIVERPOOL,DEPT CHEM,POB 174,LIVERPOOL L69 3BX,ENGLAND. RI Russell, Andrea/B-8114-2009; Russell, Andrea/A-9625-2012 NR 24 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD SEP 15 PY 1993 VL 356 IS 1-2 BP 309 EP 315 DI 10.1016/0022-0728(93)80531-L PG 7 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA LW120 UT WOS:A1993LW12000026 ER PT J AU FOIAS, C MANLEY, OP TEMAM, R AF FOIAS, C MANLEY, OP TEMAM, R TI ITERATED APPROXIMATE INERTIAL MANIFOLDS FOR NAVIER-STOKES EQUATIONS IN 2-D SO JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS LA English DT Article ID TURBULENT FLOWS C1 US DOE,GERMANTOWN,MD 20874. UNIV PARIS 11,ANALYSE NUMER LAB,F-91405 ORSAY,FRANCE. INDIANA UNIV,INST APPL MATH & SCI COMP,BLOOMINGTON,IN 47405. RP FOIAS, C (reprint author), INDIANA UNIV,DEPT MATH,BLOOMINGTON,IN 47405, USA. NR 18 TC 7 Z9 9 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 0022-247X J9 J MATH ANAL APPL JI J. Math. Anal. Appl. PD SEP 15 PY 1993 VL 178 IS 2 BP 567 EP 583 DI 10.1006/jmaa.1993.1326 PG 17 WC Mathematics, Applied; Mathematics SC Mathematics GA LZ723 UT WOS:A1993LZ72300018 ER PT J AU AJAYI, OO LEE, RH COOK, RE AF AJAYI, OO LEE, RH COOK, RE TI PLASMA-ETCHING OF STRUCTURAL CERAMICS FOR MICROSTRUCTURAL ANALYSIS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Letter ID SILICON-NITRIDE; FILMS AB Compared with chemical and thermal etching, plasma etching is an uncommon alternative for microstructural analysis of ceramic materials. In this report, we present results of the effect of CF4 + 10%O2 plasma on etching of three structural ceramic materials: Si3N4, SiC, and Al2O3. Adequate etching was observed in both Si3N4 and SiC, whereas Al2O3 was only slightly etched in the same plasma. The etching rate in Si3N4 was much higher than that in SiC. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP AJAYI, OO (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 10 TC 6 Z9 6 U1 0 U2 7 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 SEP 15 PY 1993 VL 169 IS 1-2 BP L5 EP L7 DI 10.1016/0921-5093(93)90613-J PG 3 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA LZ088 UT WOS:A1993LZ08800022 ER PT J AU TRACY, JG AARON, WS AF TRACY, JG AARON, WS TI STABLE-ISOTOPE ENRICHMENT - CURRENT AND FUTURE POTENTIAL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 16TH WORLD CONF OF THE INTERNATIONAL NUCLEAR TARGET DEVELOPMENT SOC CY SEP 21-25, 1992 CL LAB NAZL LEGNARO, LEGNARO, ITALY SP INT NUCL TARGET DEV SOC, IST NAZL FIS NUCL, GALILEO VACUUM SPECIAL EQUIPMENT, TECNOL ALTO VUOTO, CHEMOTRADE HO LAB NAZL LEGNARO AB Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to,achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. RP TRACY, JG (reprint author), OAK RIDGE NATL LAB,DEPT ISOTOPE ENRICHMENT,DIV CHEM TECHNOL,ISOTOPE TECHNOL SECT,OAK RIDGE,TN 37831, USA. NR 0 TC 7 Z9 7 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 SEP 15 PY 1993 VL 334 IS 1 BP 45 EP 50 DI 10.1016/0168-9002(93)90527-O PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LT382 UT WOS:A1993LT38200009 ER PT J AU GOBBY, PL SALAZAR, MA BUSH, H GURULE, VA FOREMAN, LR ABELL, GC GILL, JT ELLEFSON, RE SOWDERS, MH AF GOBBY, PL SALAZAR, MA BUSH, H GURULE, VA FOREMAN, LR ABELL, GC GILL, JT ELLEFSON, RE SOWDERS, MH TI A SMALL-VOLUME TRITIUM MONITOR AND FILL SYSTEM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 16TH WORLD CONF OF THE INTERNATIONAL NUCLEAR TARGET DEVELOPMENT SOC CY SEP 21-25, 1992 CL LAB NAZL LEGNARO, LEGNARO, ITALY SP INT NUCL TARGET DEV SOC, IST NAZL FIS NUCL, GALILEO VACUUM SPECIAL EQUIPMENT, TECNOL ALTO VUOTO, CHEMOTRADE HO LAB NAZL LEGNARO AB Environmental concerns demand that all tritium releases be minimized. In particular an experiment recently fielded at Los Alamos National LaboratorY required a 4 mm3 volume to be dynamically filled to a pressure of 7 MPa, while keeping the total tritium content (and potential release) below 20 Ci (1 Ci = 3.7 x 10(10) Bq). We describe the system which was designed and built for this purpose, complete with a low volume fiberoptic monitor and pressure transducers. C1 EG&G MOUND APPL TECHNOL INC,MIAMISBURG,OH 45343. RP GOBBY, PL (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 5 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 15 PY 1993 VL 334 IS 1 BP 88 EP 92 DI 10.1016/0168-9002(93)90531-L PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LT382 UT WOS:A1993LT38200013 ER PT J AU GREENE, JP AHMAD, I THOMAS, GE AF GREENE, JP AHMAD, I THOMAS, GE TI RADIOACTIVE TARGETS AND SOURCE DEVELOPMENT AT ARGONNE-NATIONAL-LABORATORY SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 16TH WORLD CONF OF THE INTERNATIONAL NUCLEAR TARGET DEVELOPMENT SOC CY SEP 21-25, 1992 CL LAB NAZL LEGNARO, LEGNARO, ITALY SP INT NUCL TARGET DEV SOC, IST NAZL FIS NUCL, GALILEO VACUUM SPECIAL EQUIPMENT, TECNOL ALTO VUOTO, CHEMOTRADE HO LAB NAZL LEGNARO ID NEUTRINO AB An increased demand for low-level radioactive targets has created the need for a laboratory dedicated to the production of these foils. A description is given of the radioactive targets produced as well as source development work being performed at the Physics Division target facility of Argonne National Laboratory (ANL). Highlights include equipment used and the techniques employed. In addition, some examples of recent source preparation are given as well as work currently in progress. RP GREENE, JP (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 15 PY 1993 VL 334 IS 1 BP 101 EP 110 DI 10.1016/0168-9002(93)90534-O PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LT382 UT WOS:A1993LT38200016 ER PT J AU THOMAS, GE GREENE, JP AF THOMAS, GE GREENE, JP TI TARGET THINNING USING A SADDLE FIELD-ION SOURCE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 16TH WORLD CONF OF THE INTERNATIONAL NUCLEAR TARGET DEVELOPMENT SOC CY SEP 21-25, 1992 CL LAB NAZL LEGNARO, LEGNARO, ITALY SP INT NUCL TARGET DEV SOC, IST NAZL FIS NUCL, GALILEO VACUUM SPECIAL EQUIPMENT, TECNOL ALTO VUOTO, CHEMOTRADE HO LAB NAZL LEGNARO ID NUCLEAR AB A system is described for thinning films using a saddle field ion source to produce targets which are difficult to make by other means. The method used, the beam profile, and characteristics of the various targets thinned are given. RP THOMAS, GE (reprint author), ARGONNE NATL LAB,9700 S CASS,ARGONNE,IL 60439, USA. NR 4 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 15 PY 1993 VL 334 IS 1 BP 132 EP 136 DI 10.1016/0168-9002(93)90540-X PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LT382 UT WOS:A1993LT38200022 ER PT J AU LOMDAHL, PS GRONBECHJENSEN, N AF LOMDAHL, PS GRONBECHJENSEN, N TI DATA-PARALLEL LANGEVIN DYNAMICS SIMULATIONS OF JOSEPHSON-JUNCTION ARRAYS SO PHYSICA D LA English DT Article; Proceedings Paper CT NATO Advanced Study Institute on Future Directions of Nonlinear Dynamics in Physical and Biological Systems, in honor of Alwyn Scotts 60th Birthday CY JUL 23-AUG 01, 1992 CL TU DENMARK, LYNGBY, DENMARK SP NATO, SCI & ENVIRONM AFFAIRS DIV, USA LAB COMMAND, ARMY RES OFF, USA EUROPEAN RES OFF, NATL SCI FDN, DANISH TECH RES COUNCIL, TU DENMARK HO TU DENMARK ID GIANT SHAPIRO STEPS AB We discuss the advantages of parallel computing with respect to both computing speed and coding techniques. As an example of an application, we show results of dynamical simulations of two dimensional Josephson lattices in external magnetic fields. Using data parallel computing, we are able to study the dynamics of very large systems and identify the interplay between spatial and temporal scales in complex systems. C1 LOS ALAMOS NATL LAB,ADV COMP LAB,LOS ALAMOS,NM 87545. RP LOMDAHL, PS (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 11 TC 1 Z9 1 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 SEP 15 PY 1993 VL 68 IS 1 BP 18 EP 26 DI 10.1016/0167-2789(93)90022-S PG 9 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA LY977 UT WOS:A1993LY97700004 ER PT J AU BARTHES, M KELLOUAI, H PAGE, G MORET, J JOHNSON, SW ECKERT, J AF BARTHES, M KELLOUAI, H PAGE, G MORET, J JOHNSON, SW ECKERT, J TI H-LOCALIZED MODE IN CHAINS OF HYDROGEN-BONDED AMIDE GROUPS SO PHYSICA D LA English DT Article; Proceedings Paper CT NATO Advanced Study Institute on Future Directions of Nonlinear Dynamics in Physical and Biological Systems, in honor of Alwyn Scotts 60th Birthday CY JUL 23-AUG 01, 1992 CL TU DENMARK, LYNGBY, DENMARK SP NATO, SCI & ENVIRONM AFFAIRS DIV, USA LAB COMMAND, ARMY RES OFF, USA EUROPEAN RES OFF, NATL SCI FDN, DANISH TECH RES COUNCIL, TU DENMARK HO TU DENMARK ID CRYSTALLINE ACETANILIDE; MOLECULAR-CRYSTALS; NEUTRON-SCATTERING; SOLITONS; SPECTRA AB New infrared measurements of the anomalous amide modes in acetanilide and its derivatives are presented. Preliminary results of structural data obtained by neutron diffraction at low temperature are also described. Besides the well-known anomalous amide-1 mode (1650 cm-1), it is shown that the NH out-of-plane bend (770 cm-1) and the ''H-bond strain'' (at about 105 cm-1) exhibit an anomalous increase of intensity proportional to the law exp(-T2/THETA2), suggesting that the amide proton bears a significant electronic distribution as formerly observed for H- localized modes. Structural data, moreover, show that the thermal ellips of the amide proton has an increasing anisotropy at 15 K. Considering these new results, the theoretical model of a self-trapped ''polaronic'' state seems to be the most consistent with the whole set of observed anomalies in this family of crystals. C1 LOS ALAMOS NATL LAB,LANSCE,LOS ALAMOS,NM 87545. RP BARTHES, M (reprint author), UNIV MONTPELLIER 2,GDPC,CC 26,F-34095 MONTPELLIER 5,FRANCE. NR 21 TC 15 Z9 15 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 SEP 15 PY 1993 VL 68 IS 1 BP 45 EP 50 DI 10.1016/0167-2789(93)90027-X PG 6 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA LY977 UT WOS:A1993LY97700009 ER PT J AU LEVY, J SHERWIN, MS THEILER, J AF LEVY, J SHERWIN, MS THEILER, J TI LOW-DIMENSIONAL CHAOS AND HIGH-DIMENSIONAL BEHAVIOR IN THE SWITCHING CHARGE-DENSITY-WAVE CONDUCTOR NBSE3 SO PHYSICAL REVIEW B LA English DT Article ID MODE-LOCKING; TIME-SERIES; TRANSPORT; DYNAMICS; INSTABILITIES AB We study the dynamics of the switching charge-density-wave (CDW) conductor NbSe3 in the presence of combined dc and ac electric fields. At a driving frequency of 20 MHz, the dynamics are both low-dimensional and chaotic, while at lower drive frequencies (<5 MHz) high-dimensional dynamics are observed. Analysis of the time series provides Lyapunov exponents, and an estimate for the number of active degrees of freedom for the low-dimensional chaotic behavior. The principal nonlinearity which gives rise to the low-dimensional chaos in switching CDW's is shown to be the hysteresis in the depinning transition, rather than the interaction between two frequencies. C1 UNIV CALIF SANTA BARBARA,CTR NONLINEAR SCI,SANTA BARBARA,CA 93106. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,INST THEORET,LOS ALAMOS,NM 87545. RP LEVY, J (reprint author), UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106, USA. RI Levy, Jeremy/A-2081-2009 OI Levy, Jeremy/0000-0002-5700-2977 NR 27 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 SEP 15 PY 1993 VL 48 IS 11 BP 7857 EP 7865 DI 10.1103/PhysRevB.48.7857 PG 9 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500011 ER PT J AU WEINBERGER, P KUDRNOVSKY, J REDINGER, J BENNETT, BI BORING, AM AF WEINBERGER, P KUDRNOVSKY, J REDINGER, J BENNETT, BI BORING, AM TI CALCULATION OF EQUILIBRIUM LATTICE-PARAMETERS AND THE HEAT OF MIXING FOR THE SYSTEM AU/PD BY THE RELATIVISTIC KORRINGA-KOHN-ROSTOKER COHERENT-POTENTIAL-APPROXIMATION METHOD SO PHYSICAL REVIEW B LA English DT Article ID RANDOM METALLIC ALLOYS; ELECTRONIC-STRUCTURE; FERMI-SURFACE; TOTAL-ENERGY; SCATTERING; ELEMENTS; AU AB Using the all-electron fully relativistic Korringa-Kohn-Rostoker coherent-potential-approximation method self-consistent total-energy calculations were performed for the system Au/Pd. The calculated equilibrium lattice constants are in fairly good agreement with the experimental data. In particular, microscopic reasons for the breaks in the variation of the lattice constants with concentration can be derived from the results. Since the calculations were carried out self-consistently for a maximum angular momentum quantum number of 2 as well as 3, an interesting quantitative comparison for the alloy total energies, spectral densities, and properties related to the Fermi energy or Fermi surface can be presented. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP WEINBERGER, P (reprint author), TECH UNIV VIENNA,INST TECH ELEKTROCHEM,GETREIDEMARKT 9-158,A-1060 VIENNA,AUSTRIA. RI KUDRNOVSKY, Josef/G-5581-2014 OI KUDRNOVSKY, Josef/0000-0002-9968-6748 NR 27 TC 9 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 SEP 15 PY 1993 VL 48 IS 11 BP 7866 EP 7871 DI 10.1103/PhysRevB.48.7866 PG 6 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500012 ER PT J AU JAFFE, JE HESS, AC AF JAFFE, JE HESS, AC TI HARTREE-FOCK STUDY OF PHASE-CHANGES IN ZNO AT HIGH-PRESSURE SO PHYSICAL REVIEW B LA English DT Article ID IIB-VIA COMPOUNDS; ELECTRONIC-STRUCTURE; PHOTOEMISSION; SEMICONDUCTORS; OXIDE AB The total energy of ZnO as a function of unit cell volume has been calculated for the zinc-blende, wurtzite, and rocksalt structures by the ab initio all-electron periodic Hartree-Fock linear-combination-of-atomic-orbitals method using a large Gaussian basis set that was variationally optimized for the solid state. Extensive convergence tests with respect to cutoffs of the real-space Coulomb and exchange series were carried out to ensure that the calculations were performed with sufficient precision. The calculated structural properties (equilibrium lattice constant, bulk modulus, etc.) of the wurtzite and rocksalt phases are in good agreement with experiment, as is the transition pressure between them (8.57 GPa versus 9-9.5 GPa experimentally), indicating that the method can reliably predict quite small energy differences between different densities or crystal structures of a nonmetallic solid. The calculated valence-band structure was also in satisfactory agreement with experiment. Detailed analysis of the charge-density distribution supports the expected picture of a transition from mixed ionic-covalent bonding in the tetrahedrally coordinated structures to predominantly ionic bonding in the high-pressure phase. RP JAFFE, JE (reprint author), PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NR 23 TC 275 Z9 291 U1 5 U2 53 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 SEP 15 PY 1993 VL 48 IS 11 BP 7903 EP 7909 DI 10.1103/PhysRevB.48.7903 PG 7 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500017 ER PT J AU DUNLAP, DH KOVANIS, V DUNCAN, RV SIMMONS, J AF DUNLAP, DH KOVANIS, V DUNCAN, RV SIMMONS, J TI FREQUENCY-TO-VOLTAGE CONVERTER BASED ON BLOCH OSCILLATIONS IN A CAPACITIVELY COUPLED GAAS-GAXAL1-XAS QUANTUM-WELL SO PHYSICAL REVIEW B LA English DT Article ID ELECTRIC-FIELD; SEMICONDUCTORS; SUPERLATTICES; LOCALIZATION AB A charged capacitor which is placed with a semiconductor in a closed loop will normally discharge in a characteristic time tau = 1/RC. We show, however, that if a semiconductor of high purity is subjected to a rf bias with frequency omega, discharge does not occur if the voltage across the capacitor is proportional to an integer multiple of HBARomega/e. Thus a rf frequency may be converted to a dc voltage. The ac to dc conversion is made possible by the interplay between Bloch oscillations induced by the electric field of the external rf source and those induced by the field from the charge residing on the capacitor. The process resembles the frequency-to-voltage conversion by a hysteretic Josephson junction, except that the evolution of the Josephson phase is replaced by the evolution of the crystal momentum of conduction electrons in the semiconductor. We discuss the parameters and conditions for which this behavior may be observed. C1 PHILIPS LAB,CTR NONLINEAR OPT,KIRTLAND AFB,NM 87117. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP DUNLAP, DH (reprint author), UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131, USA. NR 15 TC 16 Z9 16 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 SEP 15 PY 1993 VL 48 IS 11 BP 7975 EP 7980 DI 10.1103/PhysRevB.48.7975 PG 6 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500026 ER PT J AU WEITERING, HH CHEN, J DINARDO, NJ PLUMMER, EW AF WEITERING, HH CHEN, J DINARDO, NJ PLUMMER, EW TI ELECTRON CORRELATION, METALLIZATION, AND FERMI-LEVEL PINNING AT ULTRATHIN K/SI(111) INTERFACES SO PHYSICAL REVIEW B LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; SCANNING TUNNELING MICROSCOPY; SCHOTTKY-BARRIER FORMATION; X-RAY PHOTOEMISSION; SURFACE-STATES; PHOTOELECTRON-SPECTROSCOPY; COVERAGE DEPENDENCE; SI(001)2X1-K SURFACE; POTASSIUM ADSORPTION; SI(111) SURFACES AB In this paper we present a detailed photoemission study of the K/Si(111)7X7 and K/Si(111)(square-root 3 X square-root 3)R 30-degrees-B interfaces. Angle-resolved valence-band spectroscopy reveals the presence of an almost dispersionless interface state below E(F). Both interfaces are clearly nonmetallic at room-temperature saturation coverage. We critically address the issues of charge transfer and Fermi-level pinning by a detailed analysis of the K 3p and Si 2p core-level spectra. We conclude that, up to saturation coverage, correlation effects determine the electronic properties of these interfaces. Metallization occurs during the development of the second layer at cryogenic temperatures. C1 OAK RIDGE NATL LAB,DIV SOLID STATE PHYS,OAK RIDGE,TN 37831. DREXEL UNIV,DEPT PHYS & ATMOSPHER SCI,PHILADELPHIA,PA 19104. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP WEITERING, HH (reprint author), UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104, USA. NR 91 TC 79 Z9 80 U1 1 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 SEP 15 PY 1993 VL 48 IS 11 BP 8119 EP 8135 DI 10.1103/PhysRevB.48.8119 PG 17 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500044 ER PT J AU XU, J BARNES, A ALBRIDGE, R EWIG, C TOLK, N HULETT, LD AF XU, J BARNES, A ALBRIDGE, R EWIG, C TOLK, N HULETT, LD TI ROTATIONAL DISTRIBUTIONS OF EXCITED CN MOLECULES FOLLOWING ELECTRON-STIMULATED AND PHOTON-STIMULATED DESORPTION FROM SURFACES SO PHYSICAL REVIEW B LA English DT Article ID ALKALI-HALIDES; STATE DISTRIBUTIONS; DIATOMIC-MOLECULES; SINGLE-CRYSTAL; NO; BOMBARDMENT; EXCITATION; SCATTERING; RADIATION; DYNAMICS AB We report systematic experimental studies of rotational distributions of excited CN desorbed from alkali-metal and alkali-metal-halide surfaces following excitation by incident photons and electrons. Newly measured rotational spectra are found to exhibit temperature-independent non-Boltzmann features that are uniquely correlated to the particular alkali-metal component of the substrate. In addition, we observe that photon-excitation functions and cross sections for CN* desorption also depend strongly on the alkali-metal component of the substrate. The data reveal that rotational distributions arising from electron-stimulated desorption (ESD) and photon-stimulated desorption (PSD) are markedly different from those seen in thermal desorption and molecule-surface scattering. The marked substrate dependence of the rotational distributions indicates that molecular-rotation distributions following ESD and PSD are determined by direct electronic bond breaking and reflect the nature of the potential-energy surfaces that characterize CN-alkali-metal interactions. Utilizing the measured rotational distributions in conjunction with a hindered rotor model, we have constructed angular-dependent potential surfaces. C1 VANDERBILT UNIV, DEPT PHYS & ASTRON, NASHVILLE, TN 37235 USA. RP OAK RIDGE NATL LAB, POB 2008, MS 6142, OAK RIDGE, TN 37831 USA. NR 47 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1993 VL 48 IS 11 BP 8222 EP 8233 DI 10.1103/PhysRevB.48.8222 PG 12 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500055 ER PT J AU FITZSIMMONS, MR EASTMAN, JA ROBINSON, RA LAWSON, AC THOMPSON, JD MOVSHOVICH, R SATTI, J AF FITZSIMMONS, MR EASTMAN, JA ROBINSON, RA LAWSON, AC THOMPSON, JD MOVSHOVICH, R SATTI, J TI MAGNETIC ORDER IN NANOCRYSTALLINE CR AND SUPPRESSION OF ANTIFERROMAGNETISM IN BCC CR SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-DIFFRACTION; ATOMIC-STRUCTURE; TWIST BOUNDARY; CLUSTERS; IRON; FE; FERROMAGNETISM; DEPENDENCE; SIZE; GOLD AB Neutron-diffraction data and magnetization measurements of compacted nanophase Cr are presented. Two crystalline Cr phases were found, the majority phase having a bcc structure and the minority phase having an A15 structure. The 100 Bragg reflection seen in antiferromagnetically ordered coarse-grained bcc-Cr polycrystals was not observed in the nanocrystalline sample, suggesting that antiferromagnetism was suppressed in the bcc phase to at least 20 K. The suppression of antiferromagnetism may be due to small grain sizes, strain from grain boundaries or other defects, and/or concentrations of impurities, any of which may restrict the development of magnetic correlations in the bcc material. A magnetic diffraction peak corresponding to the 110 Bragg reflection of the Cr A15 lattice was observed at 20 K and was not observed at 149 or 300 K, suggesting that the minority phase of the nanocrystalline sample becomes antiferromapetically ordered at very low temperatures. Consistent with this observation, susceptibility measurements at several temperatures indicate that magnetic correlations develop below 100 K, representing at least momentary short-ranged magnetic order in the nanocrystalline sample. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP FITZSIMMONS, MR (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Eastman, Jeffrey/E-4380-2011; Lujan Center, LANL/G-4896-2012; OI Eastman, Jeff/0000-0002-0847-4265 NR 42 TC 44 Z9 45 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 SEP 15 PY 1993 VL 48 IS 11 BP 8245 EP 8253 DI 10.1103/PhysRevB.48.8245 PG 9 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500057 ER PT J AU LI, C WU, RQ FREEMAN, AJ FU, CL AF LI, C WU, RQ FREEMAN, AJ FU, CL TI ENERGETICS, BONDING MECHANISM, AND ELECTRONIC-STRUCTURE OF METAL-CERAMIC INTERFACES - AG/MGO(001) SO PHYSICAL REVIEW B LA English DT Article ID ENERGY-LOSS SPECTROSCOPY; THERMODYNAMIC PROPERTIES; GEOMETRIC RELAXATION; CHARGE DEFORMATION; IONIC-CRYSTALS; SURFACE-STATES; MGO; MODEL; BOUNDARIES; DYNAMICS AB Electronic-structure total-energy investigations for the metal-ceramic interface system Ag/MgO(001) show that the preferred adsorption site for the overlayer Ag atom is above the O site of the clean MgO(001) surface. The binding energy of the overlayer Ag atom on the MgO(001) surface is 0.3 eV/atom (0.64 J/m2). No significant charge transfer is found between the overlayer Ag and the MgO(001) substrate, and the interface effect on the MgO(001) substrate is limited to the interface layer. The Ag overlayer shows typical metal features in the electronic band structure as well as in the charge distributions. The interface O atom is slightly metallized, i.e., the occupied states at the Fermi energy have hybridized O-Ag character. Compared with the O, the Mg is less influenced by the Ag. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. RP NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. RI Wu, Ruqian/C-1395-2013 OI Wu, Ruqian/0000-0002-6156-7874 NR 30 TC 149 Z9 149 U1 1 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1993 VL 48 IS 11 BP 8317 EP 8322 DI 10.1103/PhysRevB.48.8317 PG 6 WC Physics, Condensed Matter SC Physics GA LY665 UT WOS:A1993LY66500067 ER PT J AU BRANZ, HM SCHIFF, EA AF BRANZ, HM SCHIFF, EA TI DANGLING-BOND RELAXATION AND DEEP-LEVEL MEASUREMENTS IN HYDROGENATED AMORPHOUS-SILICON SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; GAP STATES; DENSITY; ENERGY; DEFECTS AB We present a new perspective on defect levels in hydrogenated amorphous silicon (a-Si:H) that unifies relaxation effects inferred from two recent experiments. In particular, we show how earlier calculations of dangling-bond relaxation can account for both the level deepening effect reported in transient capacitance measurements and the shallowing effect reported in transient photocurrent measurements under optical bias. The former is due to dangling-bond relaxation toward a pyramidal bonding configuration, and the latter to relaxation toward a planar configuration. We comment on the many-body nature of the remarkably slow kinetics of defect relaxation. C1 SYRACUSE UNIV,DEPT PHYS,SYRACUSE,NY 13244. RP BRANZ, HM (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. OI Schiff, Eric/0000-0002-4104-7038 NR 28 TC 31 Z9 31 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1993 VL 48 IS 12 BP 8667 EP 8671 DI 10.1103/PhysRevB.48.8667 PG 5 WC Physics, Condensed Matter SC Physics GA LY959 UT WOS:A1993LY95900015 ER PT J AU BADDORF, AP ZEHNER, DM HELGESEN, G GIBBS, D SANDY, AR MOCHRIE, SGJ AF BADDORF, AP ZEHNER, DM HELGESEN, G GIBBS, D SANDY, AR MOCHRIE, SGJ TI X-RAY-SCATTERING DETERMINATION OF THE CU(110)-(2X3)N STRUCTURE SO PHYSICAL REVIEW B LA English DT Article ID CU(110)(2X3)-N STRUCTURE; SURFACE-STRUCTURE; ION-SCATTERING; NITROGEN; LEED; RECONSTRUCTION; ADSORPTION; NITRIDE; CU(100); OXYGEN AB The structure of Cu(110)-(2X3)N has been investigated with x-ray reflectivity measurements of nine independent surface rods. Observed reflectivities ranging over five orders of magnitude were compared with calculations based on structural models. A pseudo-(100) reconstruction consisting of four [110BAR] copper rows in the outermost layer for every three of the bulk is favored both by symmetry and by an R-factor analysis. An excellent fit, with an R factor of 0.0051, is obtained for this model by including a large expansion of the interlayer spacing (57% greater than bulk) and large corrugation amplitude (50%, of the bulk interlayer spacing) in the outermost layer. These values can be understood by considering a hard-sphere model of the surface structure. The corrugation results in two raised and two lowered rows of copper atoms in the outermost layer and extends to several layers into the substrate (amplitudes from 9% to 22% of the bulk interlayer spacing). Vibrational amplitudes in the reconstructed layer are anisotropically enhanced by a factor of 2.8 normal to the surface and by 1.3 within the surface plane over bulk values. Nitrogen atoms are located 0.75 angstrom above the copper layer, and form a nearly (square-root 2 X square-root 2) R 45-degrees structure with respect to the reconstructed copper. This model is shown to be consistent with most previous experimental observations. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP BADDORF, AP (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. RI Baddorf, Arthur/I-1308-2016 OI Baddorf, Arthur/0000-0001-7023-2382 NR 26 TC 29 Z9 29 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 SEP 15 PY 1993 VL 48 IS 12 BP 9013 EP 9020 DI 10.1103/PhysRevB.48.9013 PG 8 WC Physics, Condensed Matter SC Physics GA LY959 UT WOS:A1993LY95900057 ER PT J AU STEBBINS, A VEERARAGHAVAN, S AF STEBBINS, A VEERARAGHAVAN, S TI MICROWAVE BACKGROUND-RADIATION ANISOTROPY FROM SCALAR FIELD GRADIENTS SO PHYSICAL REVIEW D LA English DT Article ID COLD DARK MATTER; COSMIC STRINGS; TEXTURE; PERTURBATIONS; COSMOGONY; COSMOLOGY; PHYSICS; MODELS AB Analytic calculations of the cosmological density fluctuations and microwave background radiation anisotropies induced by gradients in a topologically trivial scalar field are presented. This anlaytic solution should provide a good test for numerical simulations of microwave anisotropy from scalar fields. To the extent that these results generalize to other scalar field models and configurations, they imply that (1) MBR measurements limit large-scale primordial variations greater than about 5 x 10(16) GeV within our horizon, (2) the total scalar field variation is a fair predictor of the magnitude of the MBR anisotropy, but is only accurate to within a factor of about three, (3) scalar fields as well as other models of seeded perturbations produce a few times more anisotropy DELTAT/T for a given density fluctuation deltarho/rho (on the same scale) than do primordial adiabatic perturbations, (4) models of scalar field seeds which produce a scale-invariant spectrum of perturbations seem to require galaxies to be more clustered than the mass on small scales, and (5) scalar fields do not ''tilt'' the Universe. C1 UNIV MASSACHUSETTS,DEPT PHYS & ASTRON,AMHERST,MA 01003. UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. RP STEBBINS, A (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMILAB MS209,BOX 500,BATAVIA,IL 60510, USA. NR 27 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP 2421 EP 2430 DI 10.1103/PhysRevD.48.2421 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600008 ER PT J AU HUET, P KAJANTIE, K LEIGH, RG LIU, BH MCLERRAN, L AF HUET, P KAJANTIE, K LEIGH, RG LIU, BH MCLERRAN, L TI HYDRODYNAMIC STABILITY ANALYSIS OF BURNING BUBBLES IN ELECTROWEAK THEORY IN QCD SO PHYSICAL REVIEW D LA English DT Article ID HADRON PHASE-TRANSITION; BARYON ASYMMETRY; SPHALERON TRANSITIONS; FINITE-TEMPERATURE; REAL-TIME; GROWTH; INSTABILITY; UNIVERSE; CHROMODYNAMICS; NUCLEATION AB Assuming that the electroweak and QCD phase transitions are first order, upon supercooling, bubbles of the new phase appear. These bubbles grow to macroscopic sizes compared to the natural scales associated with the Compton wavelengths of particle excitations. They propagate by burning the old phase into the new phase at the surface of the bubble. We study the hydrodynamic stability of the burning and find that for the velocities of interest for cosmology in the electroweak phase transition, the shape of the bubble wall is stable under hydrodynamic perturbations. Bubbles formed in the cosmological QCD phase transition are found to be a borderline case between stability and instability. C1 UNIV HELSINKI,DEPT THEORET PHYS,SF-00170 HELSINKI 17,FINLAND. UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064. UNIV MINNESOTA,SCH PHYS & ASTRON,INST THEORET PHYS,MINNEAPOLIS,MN 55455. RP HUET, P (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 45 TC 52 Z9 52 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 SEP 15 PY 1993 VL 48 IS 6 BP 2477 EP 2492 DI 10.1103/PhysRevD.48.2477 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600013 ER PT J AU COPELAND, EJ KOLB, EW LIDDLE, AR LIDSEY, JE AF COPELAND, EJ KOLB, EW LIDDLE, AR LIDSEY, JE TI RECONSTRUCTING THE INFLATION POTENTIAL - IN PRINCIPLE AND IN PRACTICE SO PHYSICAL REVIEW D LA English DT Article ID MICROWAVE BACKGROUND-RADIATION; REDSHIFT-DISTANCE SAMPLES; LARGE-SCALE STRUCTURE; GRAVITATIONAL-WAVES; EXTENDED INFLATION; DENSITY FIELDS; IRAS GALAXIES; ANISOTROPY; COBE; PERTURBATIONS AB Generalizing the original work by Hodges and Blumenthal, we outline a formalism which allows one, in principle, to reconstruct the potential of the inflaton field from knowledge of the tensor gravitational wave spectrum or the scalar density fluctuation spectrum, with special emphasis on the importance of the tensor spectrum. We provide some illustrative examples of such reconstruction. We then discuss in some detail the question of whether one can use real observations to carry out this procedure. We conclude that, in practice, a full reconstruction of the functional form of the potential will not be possible within the foreseeable future. However, with a knowledge of the dark matter components, it should soon be possible to combine intermediate-scale data with measurements of large-scale cosmic microwave background anisotropies to yield useful information regarding the potential. C1 NASA, FERMILAB ASTROPHYS CTR, FERMI NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. UNIV SUSSEX, SCH MATH & PHYS SCI, CTR ASTRON, BRIGHTON BN1 9QH, E SUSSEX, ENGLAND. QUEEN MARY & WESTFIELD COLL, SCH MATH SCI, ASTRON UNIT, LONDON E1 4NS, ENGLAND. RP UNIV SUSSEX, SCH MATH & PHYS SCI, BRIGHTON BN1 9QH, E SUSSEX, ENGLAND. NR 73 TC 143 Z9 143 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP 2529 EP 2547 DI 10.1103/PhysRevD.48.2529 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600018 ER PT J AU SHI, X SCHRAMM, DN FIELDS, BD AF SHI, X SCHRAMM, DN FIELDS, BD TI CONSTRAINTS ON NEUTRINO OSCILLATIONS FROM BIG-BANG NUCLEOSYNTHESIS SO PHYSICAL REVIEW D LA English DT Article ID EARLY UNIVERSE; PRIMORDIAL NUCLEOSYNTHESIS; SOLAR; MATTER; MASS; COSMOLOGY; MODEL; SCALE AB We discuss in detail the effect of neutrino oscillations in big bang nucleosynthesis between active and sterile neutrinos as well as between active and active neutrinos. We calculate the constraints on mixing between active and sterile neutrinos from the present observation of the primordial helium abundance and discuss the potential implications on various astrophysical and cosmological problems of such oscillations. In particular, we show that large-angle sterile neutrino mixing seems to be excluded as a MSW solution to the solar neutrino situation or a solution to the atmospheric neutrino mixing hinted at in some underground experiments. We show bow, with this constraint, the next generation of solar neutrino experiments should be able to determine the resolution of the solar neutrino problem. It is also shown how sterile neutrinos remain a viable dark matter candidate. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP SHI, X (reprint author), UNIV CHICAGO,CHICAGO,IL 60637, USA. OI Fields, Brian/0000-0002-4188-7141 NR 44 TC 131 Z9 131 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 SEP 15 PY 1993 VL 48 IS 6 BP 2563 EP 2572 DI 10.1103/PhysRevD.48.2563 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600020 ER PT J AU CALDWELL, RR GATES, E AF CALDWELL, RR GATES, E TI CONSTRAINTS ON COSMIC STRINGS DUE TO BLACK-HOLES FORMED FROM COLLAPSED COSMIC-STRING LOOPS SO PHYSICAL REVIEW D LA English DT Article ID SMALL-SCALE STRUCTURE; GRAVITATIONAL-RADIATION; EVOLUTION; NETWORK; PARTICLES; RELICS; RAYS AB The cosmological features of primordial black holes formed from collapsed cosmic string loops are studied. Observational restrictions on a population of primordial black holes are used to restrict f, the fraction of cosmic string loops which collapse to form black holes, and mu, the cosmic string mass per unit length. Using a realistic model of cosmic strings, we find that the energy density in 100 MeV photons radiated by the black holes serves as the strongest restriction on the parameters, such that f less-than-or-equal-to 10(-17) for Gmu = 10(-6). We also find that inert black hole remnants left by black holes formed from collapsed cosmic string loops cannot serve as the dark matter. If earlier, crude estimates that f approximately 10(-12) are reliable, our results severely restrict mu, and therefore limit the viability of the cosmic string large-scale structure C1 UNIV CHICAGO, CHICAGO, IL 60637 USA. RP NASA, FERMILAB ASTROPHYS CTR, FERMI NATL ACCELERATOR LAB, POB 500, BATAVIA, IL 60510 USA. OI Caldwell, Robert/0000-0001-7490-7463 NR 31 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP 2581 EP 2586 DI 10.1103/PhysRevD.48.2581 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600022 ER PT J AU PAZ, JP ZUREK, WH AF PAZ, JP ZUREK, WH TI ENVIRONMENT-INDUCED DECOHERENCE, CLASSICALITY, AND CONSISTENCY OF QUANTUM HISTORIES SO PHYSICAL REVIEW D LA English DT Article ID LOGICAL REFORMULATION; BROWNIAN-MOTION; WAVE PACKET; MECHANICS AB We prove that for an open system, in the Markovian regime, it is always possible to construct an infinite number of nontrivial sets of histories that exactly satisfy the probability sum rules. In spite Of being perfectly consistent, these sets manifest a very nonclassical behavior: they are quite unstable under the addition of an extra instant to the list of times defining the history. To eliminate this feature-the implications of which we discuss-and to achieve the stability that characterizes the quasiclassical domain, it is necessary to separate the instants which define the history by time intervals significantly larger than the typical decoherence time. In this case environment induced superselection is very effective. The quasiclassical domain is defined by predictably evolving perferred states, ''pointer projectors,'' which give rise to consistent preferred sets of histories. RP LOS ALAMOS NATL LAB, T6, MS-B288, LOS ALAMOS, NM 87545 USA. RI Paz, Juan/C-5947-2008 NR 36 TC 93 Z9 94 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP 2728 EP 2738 DI 10.1103/PhysRevD.48.2728 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600035 ER PT J AU SEVRIN, A THIELEMANS, K TROOST, W AF SEVRIN, A THIELEMANS, K TROOST, W TI RELATION BETWEEN LINEAR AND NONLINEAR N = 3,4 SUPERGRAVITY THEORIES SO PHYSICAL REVIEW D LA English DT Article ID SUPERCONFORMAL ALGEBRAS; 2 DIMENSIONS; GRAVITY; COLOR AB The effective actions for d = 2, N = 3,4 chiral supergravities with a linear and a nonlinear gauge algebra are related to each other by a quantum reduction; the latter is obtained from the former by putting quantum currents equal to zero. This implies that the renormalization factors for the quantum actions are identical. C1 LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. UNIV LEUVEN,INST THEORET FYS,B-3001 LOUVAIN,BELGIUM. RP SEVRIN, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Sevrin, Alexander/D-5794-2017; OI Sevrin, Alexander/0000-0001-6564-9941; Thielemans, Kris/0000-0002-5514-199X NR 29 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP 2789 EP 2796 DI 10.1103/PhysRevD.48.2789 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600040 ER PT J AU HEISELBERG, H PETHICK, CJ AF HEISELBERG, H PETHICK, CJ TI TRANSPORT AND RELAXATION IN DEGENERATE QUARK PLASMAS SO PHYSICAL REVIEW D LA English DT Article ID TRANSVERSE INTERACTIONS; FINITE TEMPERATURE; GLUON; QCD AB Transport coefficients and relaxation times are calculated for degenerate quark matter within perturbative QCD for temperatures T and inverse screening lengths q(D) much smaller than the quark chemical potentials. The important physical effect is ''dynamical screening'' of transverse interactions. The physics changes significantly when T approximately q(D) and an relaxation times change from a power law dependence on T for T much less than q(D) to a power law times a logarithmic one for T much greater than q(D). ResultS differ very much from standard Fermi liquid results in both limits. Detailed analytical calculations of the momentum relaxation time for interpenetrating quark plasmas, the diffusion coefficient, electrical conductivity, viscosity, and the thermal conductivity are performed to leading orders in the coupling constant. Applications to diffusion processes in the burning of neutron stars into strange quark matter and to electrical conduction in quark matter are given. C1 LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. NORDITA,DK-2100 COPENHAGEN 0,DENMARK. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. RP HEISELBERG, H (reprint author), NIELS BOHR INST,BLEGDAMSVEJ 17,DK-2100 COPENHAGEN 0,DENMARK. OI Heiselberg, Henning/0000-0003-2229-2000 NR 28 TC 96 Z9 98 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 SEP 15 PY 1993 VL 48 IS 6 BP 2916 EP 2928 DI 10.1103/PhysRevD.48.2916 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600056 ER PT J AU BAIG, M FORT, H KOGUT, JB KIM, S SINCLAIR, DK AF BAIG, M FORT, H KOGUT, JB KIM, S SINCLAIR, DK TI LOGARITHMIC TRIVIALITY OF SCALAR QUANTUM ELECTRODYNAMICS SO PHYSICAL REVIEW D LA English DT Article ID PARTITION-FUNCTION; DIMENSIONS; ZEROS; MODEL AB Using finite size scaling and histogram methods we obtain results from lattice simulations indicating the logarithmic triviality of scalar quantum electrodynamics, even if the bare gauge coupling is large. Simulations of the noncompact formulation of the lattice Abelian Higgs model with fixed length scalar fields on L4 lattices with L ranging from 6 through 20 indicate a line of second-order critical points. Lengthy runs for each L produce specific-heat peaks which grow logarithmically with L and whose critical coupling shift with L picking out a correlation length exponent of 0.50(2) consistent with mean-field theory. C1 UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. RP BAIG, M (reprint author), UNIV AUTONOMA BARCELONA,INST FIS ALTES ENERGIES,FIS TEOR GRP,E-08193 BARCELONA,SPAIN. NR 17 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 1993 VL 48 IS 6 BP R2385 EP R2388 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LY666 UT WOS:A1993LY66600004 ER PT J AU SANDBERG, WS TERWILLIGER, TC AF SANDBERG, WS TERWILLIGER, TC TI ENGINEERING MULTIPLE PROPERTIES OF A PROTEIN BY COMBINATORIAL MUTAGENESIS SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE PROTEIN ENGINEERING; ADDITIVITY; STABILITY; DNA BINDING PROTEIN ID GENE-V-PROTEIN; DNA-BINDING-PROTEIN; T4 LYSOZYME; STAPHYLOCOCCAL NUCLEASE; SUBSTRATE-SPECIFICITY; LAMBDA-REPRESSOR; DISULFIDE BONDS; SUBTILISIN BPN'; ALPHA-HELIX; STABILITY AB A method for simultaneously engineering multiple properties of a protein, based on the observed additivity of effects of individual mutations, is presented. We show that, for the gene V protein of bacteriophage f1, effects of double mutations on both protein stability and DNA binding affinity are approximately equal to the sums of the effects of the constituent single mutations. This additivity of effects implies that it is possible to deliberately construct mutant proteins optimized for multiple properties by combination of appropriate single mutations chosen from a characterized library. C1 UNIV CHICAGO,DEPT BIOCHEM & MOLEC BIOL,CHICAGO,IL 60637. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 45 TC 54 Z9 54 U1 0 U2 4 PU NATL ACAD SCIENCES 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 SEP 15 PY 1993 VL 90 IS 18 BP 8367 EP 8371 DI 10.1073/pnas.90.18.8367 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LX750 UT WOS:A1993LX75000015 PM 8378307 ER PT J AU BOURKE, MAM GOLDSTONE, JA SHI, N ALLISON, JE STOUT, MG LAWSON, AC AF BOURKE, MAM GOLDSTONE, JA SHI, N ALLISON, JE STOUT, MG LAWSON, AC TI MEASUREMENT AND PREDICTION OF STRAIN IN INDIVIDUAL PHASES OF A 2219AL/TIC/15P-T6 COMPOSITE DURING LOADING SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID NEUTRON-DIFFRACTION C1 FORD MOTOR CO,DEARBORN,MI 48121. RP BOURKE, MAM (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 15 TC 22 Z9 22 U1 1 U2 2 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 SEP 15 PY 1993 VL 29 IS 6 BP 771 EP 776 DI 10.1016/0956-716X(93)90224-G PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LP598 UT WOS:A1993LP59800010 ER PT J AU RESCIGNO, TN ELZA, BK LENGSFIELD, BH AF RESCIGNO, TN ELZA, BK LENGSFIELD, BH TI AN AB-INITIO TREATMENT OF NEAR-THRESHOLD VIBRATIONAL-EXCITATION OF H2 BY ELECTRON-IMPACT - NEW PERSPECTIVES ON DISCREPANCIES BETWEEN CROSSED-BEAM AND SWARM DATA SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID LOW-ENERGY ELECTRONS; ROVIBRATIONAL EXCITATION; MOLECULE SCATTERING; SECTIONS; H-2; COLLISIONS; HYDROGEN AB New crossed-beam measurements of the vibrational excitation cross section Of H-2 are at variance with earlier determinations based on analysis of swarm data. This discrepancy poses a dilemma, as the modeling of a variety of plasma processes depends on cross sections derived from transport analysis. We present calculated cross sections for vibrational excitation of H-2 by low-energy electron impact using a fully ab initio treatment of the electronic motion with incorporation of nonadiabatic nuclear effects through an approximate off-shell T-matrix formalism. Our cross sections are in good agreement with recent data and are substantially larger than the values deduced from swarm data. RP RESCIGNO, TN (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 24 TC 22 Z9 22 U1 0 U2 1 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 SEP 14 PY 1993 VL 26 IS 17 BP L567 EP L573 DI 10.1088/0953-4075/26/17/007 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LY840 UT WOS:A1993LY84000007 ER PT J AU AHLUWALIA, DV GOLDMAN, T AF AHLUWALIA, DV GOLDMAN, T TI SPACE-TIME SYMMETRIES AND VORTICES IN THE COSMOS SO MODERN PHYSICS LETTERS A LA English DT Article AB By carefully studying the (1, 0) + (0, 1) representation space for massive particles we point to the existence of certain inherent tachyonic dispersion relations: E2 = p2 - m2. We put forward an interpretation that exploits these ''negative mass squared'' solutions; rotational invariance is spontaneously broken. Relevance of these results to the vortices in the cosmos is pointed out. C1 LOS ALAMOS NATL LAB,MEDIUM ENERGY PHYS THEORY GRP,LOS ALAMOS,NM 87545. RP AHLUWALIA, DV (reprint author), LOS ALAMOS NATL LAB,NUCL & PARTICLE PHYS RES GRP,MP-9,MS H-846,LOS ALAMOS,NM 87545, USA. NR 0 TC 14 Z9 14 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 SEP 14 PY 1993 VL 8 IS 28 BP 2623 EP 2630 DI 10.1142/S0217732393003007 PG 8 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA MC749 UT WOS:A1993MC74900002 ER PT J AU SCHONFELD, T STOCKER, H GREINER, W SORGE, H AF SCHONFELD, T STOCKER, H GREINER, W SORGE, H TI STOPPING POWER IN NUCLEUS-NUCLEUS COLLISIONS AT ROOT-S = 200 AGEV SO MODERN PHYSICS LETTERS A LA English DT Article AB The microscopic phase space approach RQMD1 is used to investigate the stopping power of very heavy nuclei at collider energies. We find no gap in the rapidity distribution around mid-rapidity even at RHIC energies (square-root s = 200 AGeV), but rather strong filling of the mid-rapidity region. Neither is there a broad plateau for secondaries nor are the correlations between space-time and momentum as strong as in the Bjorken-McLarren scenario. This renders the Bjorken picture questionable at these energies for systems of combined mass A almost-equal-to 400. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP SCHONFELD, T (reprint author), JOHANN WOLFGANG GOETHE UNIV,INST THEORET PHYS,POSTFACH 111932,W-6000 FRANKFURT 11,GERMANY. RI Stoecker, Horst/D-6173-2013 OI Stoecker, Horst/0000-0002-3282-3664 NR 0 TC 18 Z9 18 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 SEP 14 PY 1993 VL 8 IS 28 BP 2631 EP 2641 DI 10.1142/S0217732393003019 PG 11 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA MC749 UT WOS:A1993MC74900003 ER PT J AU MCCARTY, KF MEEKS, E KEE, RJ LUTZ, AE AF MCCARTY, KF MEEKS, E KEE, RJ LUTZ, AE TI SCALABLE STAGNATION-FLOW REACTORS FOR UNIFORM MATERIALS DEPOSITION - APPLICATION TO COMBUSTION SYNTHESIS OF DIAMOND SO APPLIED PHYSICS LETTERS LA English DT Article ID FLAT FLAME; GROWTH; FILMS AB We describe two inherently scaleable geometries for chemical-vapor-deposition and heat-transfer processes that are based on stagnation flows. The ''coflow'' and ''trumpet-bell'' designs result in radially uniform fluxes to surfaces and they optimize the use of reagents. Using a trumpet-bell burner, we have grown uniform films of diamond from a substrate-stabilized flat flame of C2H2/H-2/O2. RP MCCARTY, KF (reprint author), SANDIA NATL LABS CALIF,LIVERMORE,CA 94551, USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 12 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 13 PY 1993 VL 63 IS 11 BP 1498 EP 1500 DI 10.1063/1.109668 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100016 ER PT J AU DOMANSKY, K LENG, Y WILLIAMS, CC JANATA, J PETELENZ, D AF DOMANSKY, K LENG, Y WILLIAMS, CC JANATA, J PETELENZ, D TI MAPPING OF MOBILE CHARGES ON INSULATOR SURFACES WITH THE ELECTROSTATIC FORCE MICROSCOPE SO APPLIED PHYSICS LETTERS LA English DT Article ID CONTACT AB Migration of surface ions in lateral fields on insulator surfaces may modify the electrical characteristics of underlying semiconductor structures causing device instabilities. A high sensitivity electrostatic force microscope is used to image the movement and spatial distribution of surface ions on Si3N4. Mobile surface ions are distributed by the fringing fields of a p-n junction and an open-gate field-effect transistor. The surface charge distribution and topography are imaged simultaneously on a micrometer scale. C1 UNIV UTAH, DEPT PHYS, SALT LAKE CITY, UT 84112 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. RP DOMANSKY, K (reprint author), UNIV UTAH, HEDCO MICROFABRICAT FACIL, SALT LAKE CITY, UT 84112 USA. NR 20 TC 53 Z9 54 U1 2 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 SEP 13 PY 1993 VL 63 IS 11 BP 1513 EP 1515 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100021 ER PT J AU ROBERTSON, J WARREN, WL TUTTLE, BA DIMOS, D SMYTH, DM AF ROBERTSON, J WARREN, WL TUTTLE, BA DIMOS, D SMYTH, DM TI SHALLOW PB3+ HOLE TRAPS IN LEAD-ZIRCONATE-TITANATE FERROELECTRICS SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE; CERAMICS; SRTIO3 AB A combination of electron paramagnetic resonance and band structure calculations is used to show that the Pb2+ ions in lead zirconate titanate materials can act as shallow hole traps to give Pb3+ centers. The Pb3+ centers are created by optical illumination and are found to be metastable at room temperature. Their decay kinetics follow a stretched exponential function which suggests dispersive transport. The traps have the same character as the upper valence band which is formed from the hybridization of Pb s and O p states. C1 SANDIA NATL LABS,DEPT GLASS & ELECTR CERAM,ALBUQUERQUE,NM 87185. LEHIGH UNIV,MAT RES CTR,BETHLEHEM,PA 18015. RP ROBERTSON, J (reprint author), NATL POWER LABS,LEATHERHEAD KT22 7SE,SURREY,ENGLAND. NR 22 TC 71 Z9 72 U1 0 U2 7 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 SEP 13 PY 1993 VL 63 IS 11 BP 1519 EP 1521 DI 10.1063/1.110761 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100023 ER PT J AU SEAGER, CH ANDERSON, RA AF SEAGER, CH ANDERSON, RA TI REVERSIBLE CHANGES OF THE CHARGE-STATE OF DONOR HYDROGEN COMPLEXES INITIATED BY HOLE CAPTURE IN SILICON SO APPLIED PHYSICS LETTERS LA English DT Article ID ENHANCED DISSOCIATION; CRYSTALLINE SILICON AB The effect of light-injected holes on phosphorus/hydrogen-pairs has been examined in silicon. Previous studies have shown that light soaking appears to debond H from phosphorus, thereby returning it to the positive charge state. Here, we demonstrate that this charge state change is partially reversible if samples are held in electronic equilibrium for periods of hours to days. Since this recovery process can be delayed for days by depleting the light-soaked region, it appears that freed hydrogen is not merely returning to donors, but that the original hole capture event is merely creating a different charge state of the P.H pair. We also demonstrate that the kinetics of the hole-induced conversion process is markedly different in depletion than in zero bias and suggest that this is due to the presence of the recovery process which can only occur in the presence of free electrons. RP SEAGER, CH (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 10 TC 13 Z9 13 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 SEP 13 PY 1993 VL 63 IS 11 BP 1531 EP 1533 DI 10.1063/1.110739 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100027 ER PT J AU KEPLER, RG CAHILL, PA AF KEPLER, RG CAHILL, PA TI PHOTOINDUCED CHARGE-TRANSFER AND CHARGE-CARRIER GENERATION IN POLYSILANE FILMS CONTAINING C-60 MOLECULES SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRON-TRANSFER; PHOTOCONDUCTIVITY; EXCITATIONS; TRANSPORT; POLYMERS AB We have studied charge carrier generation and transport in poly(methylphenylsilane) films containing C60 molecules, and have found that the quantum efficiency for carrier generation is increased by more than an order of magnitude over poly(methylphenylsilane) films not containing C60 and that hole transport is unaffected. We also measured the electroabsorption spectrum of the composite films and found no evidence for charge transfer transitions. We conclude that electrons are transferred from poly(methylphenylsilane) to C60 molecules that have been excited to their lowest energy absorption band at about 2 eV. RP KEPLER, RG (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 10 TC 55 Z9 56 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 SEP 13 PY 1993 VL 63 IS 11 BP 1552 EP 1554 DI 10.1063/1.110746 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100034 ER PT J AU WHEELER, R KIRK, MA MARWICK, AD CIVALE, L HOLTZBERG, FH AF WHEELER, R KIRK, MA MARWICK, AD CIVALE, L HOLTZBERG, FH TI COLUMNAR DEFECTS IN YBA2CU3O7-DELTA INDUCED BY IRRADIATION WITH HIGH-ENERGY HEAVY-IONS SO APPLIED PHYSICS LETTERS LA English DT Article ID CRYSTALS; FILMS AB Defect microstructures in three YBa2Cu3O7-delta single crystals irradiated with different high energy heavy ions show dramatically different damage morphologies. For Sn and Au projectiles with total energies of 580 MeV and 1.0 GeV, respectively, highly aligned tracks are observed which extend for many microns in the crystals. However, irradiation with 1.4 GeV Br ions results in the formation of spherical damage regions widely separated along the ion path through the entire crystal. The continuity of damage along the ion path for the different projectiles varies with the magnitude of the electronic energy loss. C1 CTR ATOM BARILOCHE,RA-8400 BARILOCHE,ARGENTINA. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP WHEELER, R (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 12 TC 27 Z9 27 U1 1 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 SEP 13 PY 1993 VL 63 IS 11 BP 1573 EP 1575 DI 10.1063/1.110753 PG 3 WC Physics, Applied SC Physics GA LX161 UT WOS:A1993LX16100041 ER PT J AU FORD, TA AGNEW, SF SWANSON, BI AF FORD, TA AGNEW, SF SWANSON, BI TI AB-INITIO MOLECULAR-ORBITAL STUDIES OF THE VIBRATIONAL-SPECTRA OF NITROSYL FLUORIDE AND CHLORIDE MONOMERS AND DIMERS .1. ONF AND ONCL SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article ID THEORETICAL EQUILIBRIUM GEOMETRIES; HYDROGEN-BONDED COMPLEXES; INFRARED-SPECTRA; ELECTRON CORRELATION; FORCE-FIELD; BASIS SET; HYDROXYLAMINE; INTENSITIES; CONSTANTS; AMMONIA AB The wavenumbers, and infrared and Raman band intensities of nitrosyl fluoride and chloride have been calculated, using the GAUSSIAN 86 and GAUSSIAN 88 computer program packages and the 6-31G* basis set, at the Hartree-Fock and second-order Moller-Plesset levels of theory. Optimized geometries and force constants are also reported and discussed in relation to experimental data, where available. C1 LOS ALAMOS NATL LAB,ISOTOPE & NUCL CHEM GRP,LOS ALAMOS,NM 87545. NR 33 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 J9 J MOL STRUCT JI J. Mol. Struct. PD SEP 13 PY 1993 VL 297 BP 255 EP 264 DI 10.1016/0022-2860(93)80181-T PG 10 WC Chemistry, Physical SC Chemistry GA LX313 UT WOS:A1993LX31300031 ER PT J AU FORD, TA AGNEW, SF SWANSON, BI AF FORD, TA AGNEW, SF SWANSON, BI TI AB-INITIO MOLECULAR-ORBITAL STUDIES OF THE VIBRATIONAL-SPECTRA OF NITROSYL FLUORIDE AND CHLORIDE MONOMERS AND DIMERS .2. (ONF)2 AND (ONCL)2 SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article ID HYDROGEN-BONDED COMPLEXES; DIPOLE-MOMENT DERIVATIVES; INFRARED-SPECTRA; AMMONIA COMPLEX; POLAR TENSORS; HYDROXYLAMINE; WATER; INTENSITIES AB The optimized structures, and the infrared and Raman spectra of the dimers of nitrosyl fluoride and nitrosyl chloride have been predicted by means of ab initio molecular orbital theory, using the GAUSSIAN 86 and GAUSSIAN 88 computer programs. The calculations were carried out at both the restricted Hartree Fock and the second order Moller Plesset levels of theory, using the 6-31G* split-valence polarized basis set. The results have been compared with a similar set of calculations on the respective monomers and, in the case of nitrosyl chloride, with the Raman spectrum of the pure solid and with the infrared spectra of the solid and of nitrosyl chloride isolated in argon matrices. The energies of dimerization, internal valence force constants and atomic polar tensors, and their invariants have also been determined, and have been rationalized on the basis of the derived structures and the proposed mode of interaction. C1 LOS ALAMOS NATL LAB, ISOTOPE & NUCL CHEM GRP, LOS ALAMOS, NM 87545 USA. NR 28 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 EI 1872-8014 J9 J MOL STRUCT JI J. Mol. Struct. PD SEP 13 PY 1993 VL 297 BP 265 EP 275 DI 10.1016/0022-2860(93)80182-U PG 11 WC Chemistry, Physical SC Chemistry GA LX313 UT WOS:A1993LX31300032 ER PT J AU CHANTRANUPONG, L HIRSCH, G BUENKER, RJ DILLON, MA AF CHANTRANUPONG, L HIRSCH, G BUENKER, RJ DILLON, MA TI THEORETICAL CONFIGURATION-INTERACTION STUDY OF THE VERTICAL ELECTRONIC-SPECTRUM OF ETHANE SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article ID ENERGY EXTRAPOLATION; CI CALCULATIONS AB Ab initio multireference single- and double-excitation configuration interaction calculations are reported for the ground and 32 excited electronic states of ethane, as well as its two lowest ionic states, 2E(g) and 2A1g. The transition energy results indicate that the 3a1g molecular orbital is 0.3 0.6 eV more stable than the 1e(g) lowest unoccupied molecular orbital for the ethane D3d equilibrium conformation. The strongest transition is computed to occur for the 3a1g --> 3psigma 1A2u - 1A1g excitation at 10.58 eV, with an optical f value of 0.1152. The n = 4 Rydberg transitions are also calculated and are found to occur with roughly 40% of their n = 3 counterparts. The observed broadness of the ethane UV spectrum is believed to be caused primarily by the high density of Rydberg upper states, as well as significant relaxation effects which occur upon excitation from the ethane electronic ground state. The fact that the strongest ethane transition is computed to have a vertical energy which is 1.2-1.4 eV higher than the center of the observed discrete bands at 9.4 eV suggests that the previous interpretation of this structure should be reconsidered. C1 BERG UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH THEORET CHEM 9,GAUSSTR 20,D-42097 WUPPERTAL 1,GERMANY. ARGONNE NATL LAB,DIV ENVIRONM PHYS,ARGONNE,IL 60439. NR 18 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 J9 J MOL STRUCT JI J. Mol. Struct. PD SEP 13 PY 1993 VL 297 BP 373 EP 381 DI 10.1016/0022-2860(93)80192-X PG 9 WC Chemistry, Physical SC Chemistry GA LX313 UT WOS:A1993LX31300042 ER PT J AU MIN, BI KANG, JS HONG, JH JUNG, SW JEONG, JI LEE, YP CHOI, SD LEE, WY YANG, CJ OLSON, CG AF MIN, BI KANG, JS HONG, JH JUNG, SW JEONG, JI LEE, YP CHOI, SD LEE, WY YANG, CJ OLSON, CG TI THE ELECTRONIC-STRUCTURE OF THE NOVEL RARE-EARTH PERMANENT-MAGNET SM2FE17N3 SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID METALS AB Electronic and magnetic properties of the novel rare-earth permanent magnet Sm2Fe17N3 are investigated by performing self-consistent local density-functional electronic-structure calculations. We also report valence-band photoemission studies on Sm2Fe17, which is the matrix compound of SM2Fe17N3, and on Nd2Fe17 for comparison. Employing the LMTO (linearized muffin-tin orbital) band method, we have obtained electronic band structures for both paramagnetic and ferromagnetic phases of Sm2Fe17N3, SM2Fe17, and Nd2Fe17. It is found that N atoms substantially reduce the magnetic moment of neighbouring Fe atoms through the hybridization interaction and play a role in stabilizing the structure. The average magnetic moment of Fe atoms in the ferromagnetic phase of SM2Fe17N3 is estimated to be 2.29mu(B), which is approximately 6% larger than the magnetic moment of SM2Fe17, 2.16mu(B). Photoemission spectroscopy (PES) measurements show that the bulk Nd and Sm atoms are nearly trivalent in Nd2Fe17 and Sm2Fe17, and that broad 4f PES line shapes reflect the hybridization between Nd/Sm 4f and Fe 3d states. The experimental Fe 3d PES spectra are compared with the calculated Fe 3d angular-momentum-projected local density of states (PLDOS) for Nd2Fe17 and SM2Fe17. The measured Fe 3d PEs band widths are comparable to the calculated Fe 3d PLDos widths below E(F), but the peak positions lie in between the calculated peaks of the paramagnetic and ferromagnetic Fe 3d PLDOS. C1 RES INST IND SCI & TECHNOL,POHANG 790600,SOUTH KOREA. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP MIN, BI (reprint author), POHANG INST SCI & TECHNOL,DEPT PHYS,POHANG 790600,SOUTH KOREA. NR 26 TC 5 Z9 5 U1 1 U2 4 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 SEP 13 PY 1993 VL 5 IS 37 BP 6911 EP 6924 DI 10.1088/0953-8984/5/37/009 PG 14 WC Physics, Condensed Matter SC Physics GA LX728 UT WOS:A1993LX72800009 ER PT J AU CHENG, SZD WU, SS CHEN, JH ZHUO, QH QUIRK, RP VONMEERWALL, ED HSIAO, BS HABENSCHUSS, A ZSCHACK, PR AF CHENG, SZD WU, SS CHEN, JH ZHUO, QH QUIRK, RP VONMEERWALL, ED HSIAO, BS HABENSCHUSS, A ZSCHACK, PR TI ISOTHERMAL THICKENING AND THINNING PROCESSES IN LOW-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) FRACTIONS CRYSTALLIZED FROM THE MELT .4. END-GROUP DEPENDENCE SO MACROMOLECULES LA English DT Article ID POLYMER CRYSTALS; SINGLE-CRYSTALS; LONG PARAFFINS; ETHYLENE-OXIDE; GROWTH-RATE; POLYETHYLENE; DIFFUSION; MORPHOLOGY; REPTATION; ONSET AB A series of low molecular weight poly(ethylene oxide) (PEO) fractions with different molecular weights (MW=3000 and 7100) and end groups (-OH, -OCH3, -OC(CH3)3, and -OC6H5) have been systematically studied. The end-group effect on diffusional motion in the melt of these PEO fractions was characterized by self-diffusion coefficient measurements through nuclear magnetic resonance. Wide-angle X-ray diffraction experiments indicated that the crystal structures of the PEO fractions with different end groups were identical during and after crystallization. The existence of nonintegral folding chain (NIF) crystals in these PEO fractions in a wide undercooling region was observed by time-resolved synchrotron small-angle X-ray scattering, differential scanning calorimetry, and transmission electron microscopy experiments. The integral folding chain (IF) crystals were found to be formed through both thickening and thinning processes during and/or after the NIF crystallization. It was also found that, with increasing molecular weight and size of the end group, the thickening and thinning processes were increasingly hampered. Of additional interest, the fold length of initial NIF crystals not only increases with crystallization temperature (or decreasing undercooling) for each PEO fraction as commonly observed in polymer lamellar crystals but also changes with the size of the end group. The kinetics of transformation from NIF to IF crystals is explained through the chain sliding diffusional motion along the direction perpendicular to the lamellar surface, which is end-group size dependent. Linear crystal growth rate data measured via polarized light microscopy confirmed that the existence of bulky end groups reduces NIF crystal growth rates for PEO (MW = 3000) fractions. With increasing molecular weight, the end-group dependence gradually vanishes due to the introduction of chain entanglement. C1 UNIV AKRON,DEPT PHYS,AKRON,OH 44325. DUPONT CO INC,DIV FIBER,EXPTL STN,WILMINGTON,DE 19880. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP CHENG, SZD (reprint author), UNIV AKRON,INST & DEPT POLYMER SCI,AKRON,OH 44325, USA. NR 52 TC 74 Z9 76 U1 2 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 13 PY 1993 VL 26 IS 19 BP 5105 EP 5117 DI 10.1021/ma00071a020 PG 13 WC Polymer Science SC Polymer Science GA LX932 UT WOS:A1993LX93200020 ER PT J AU PLOMPEN, AJM HARAKEH, MN HESSELINK, WHA VANTHOF, G KALANTARNAYESTANAKI, N VANSCHAGEN, JPS CARPENTER, MP AHMAD, I BEARDEN, IG JANSSENS, RVF KHOO, TL LAURITSEN, T LIANG, Y GARG, U REVIOL, W YE, D AF PLOMPEN, AJM HARAKEH, MN HESSELINK, WHA VANTHOF, G KALANTARNAYESTANAKI, N VANSCHAGEN, JPS CARPENTER, MP AHMAD, I BEARDEN, IG JANSSENS, RVF KHOO, TL LAURITSEN, T LIANG, Y GARG, U REVIOL, W YE, D TI COLLECTIVE AND QUASI-PARTICLE STRUCTURES IN PB-192 SO NUCLEAR PHYSICS A LA English DT Article DE 173YB(MG-124, 5N); E = 132 MEV; MEASURED E-GAMMA,I-GAMMA, GAMMA-GAMMA(THETA), GAMMA-GAMMA(T), GAMMA-GAMMA-COIN; 192PB DEDUCED LEVELS, J, PI; ENRICHED TARGET; COMPTON-SUPPRESSED GE-DETECTORS; CENTRAL ARRAY OF BGO DETECTORS; CRANKED SHELL MODEL CALCULATIONS ID LEAD ISOTOPES; SUPERDEFORMED BAND; PB ISOTOPES; STATES; NUCLEI; INTRUDER; BEHAVIOR; HG-191 AB The structure of 192Pb has been investigated using the Yb-173(Mg-24, 5n) reaction at E(b) = 132 MeV. The level scheme has been extended up to an excitation energy of 7 MeV and a spin of 23 HBAR. Two collective bands of levels linked by M1 transitions and four groups of states of non-collective character have been observed. Based on comparison with experimental data on odd-A Tl isotopes and with cranked shell-model calculations assuming an oblate shape, the collective Ml bands are interpreted as having an underlying proton 2-quasiparticle configuration coupled to a pair of rotation-aligned i13/2 neutrons. The four groups of non-collective level-sequences are understood as 4-quasiparticle excitations associated with aligned neutron 2-quasiparticle states that involve a mixture of neutron and proton degrees of freedom. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV NOTRE DAME,NOTRE DAME,IN 46556. RP PLOMPEN, AJM (reprint author), FREE UNIV AMSTERDAM,FAC NAT KUNDE & STERRENKUNDE,1081 HV AMSTERDAM,NETHERLANDS. RI Bearden, Ian/M-4504-2014; Carpenter, Michael/E-4287-2015; Kalantar-Nayestanaki, Nasser/A-3582-2016 OI Bearden, Ian/0000-0003-2784-3094; Carpenter, Michael/0000-0002-3237-5734; Kalantar-Nayestanaki, Nasser/0000-0002-1033-7200 NR 43 TC 31 Z9 31 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 SEP 13 PY 1993 VL 562 IS 1 BP 61 EP 87 DI 10.1016/0375-9474(93)90032-S PG 27 WC Physics, Nuclear SC Physics GA MA654 UT WOS:A1993MA65400004 ER PT J AU PLOMPEN, AJM BLOMQVIST, J CARPENTER, MP HARAKEH, MN HESSELINK, WHA JANSSENS, RVF LIOTTA, RJ SANDALESCU, N AF PLOMPEN, AJM BLOMQVIST, J CARPENTER, MP HARAKEH, MN HESSELINK, WHA JANSSENS, RVF LIOTTA, RJ SANDALESCU, N TI NONCOLLECTIVE DEGREES OF FREEDOM IN PB-192 SO NUCLEAR PHYSICS A LA English DT Article ID LEAD ISOTOPES; STATES; EXCITATIONS; NUCLEI AB Two positive-parity and two negative-parity groups of states of non-collective character with excitation energies ranging from 3 to 7 MeV and spins as high as 21 HBAR have been established in 192Pb. The main features of each group are described phenomenologically as four-quasiparticle configurations, arising from coupling of the 2(1)+, 4(1)+ and 6(1)+ states to a specific aligned neutron two-quasiparticle configuration. Supporting evidence for this interpretation and the importance of proton excitations in this singly closed-shell nucleus is obtained from the predictions of the quasiparticle multi-step shell model (QMSM). In addition, a four-quasiparticle structure of predominant neutron character is proposed on the basis of comparisons with the experimental data on 194Pb and with the results of the QMSM calculations. C1 MANNE SIEGBAHN INST,S-10405 STOCKHOLM,SWEDEN. KERNFYS VERSNELLER INST,9747 AA GRONINGEN,NETHERLANDS. INST ATOM PHYS,BUCHAREST,ROMANIA. ARGONNE NATL LAB,ARGONNE,IL 60439. RP PLOMPEN, AJM (reprint author), FREE UNIV AMSTERDAM,FAC NAT KUNDE & STERRENKUNDE,BOELELAAN 1081,1081 HV AMSTERDAM,NETHERLANDS. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 20 TC 2 Z9 2 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 SEP 13 PY 1993 VL 562 IS 1 BP 88 EP 100 DI 10.1016/0375-9474(93)90033-T PG 13 WC Physics, Nuclear SC Physics GA MA654 UT WOS:A1993MA65400005 ER PT J AU MOLTZ, DM ROBERTSON, JD NORMAN, EB BURDE, J BEAUSANG, CW AF MOLTZ, DM ROBERTSON, JD NORMAN, EB BURDE, J BEAUSANG, CW TI LOW-LYING LEVEL STRUCTURE OF KR-73 SO NUCLEAR PHYSICS A LA English DT Article ID HIGH-SPIN STATES; ISOTOPES; DEFORMATION AB We have used the Ca-40(Ar-36, 2pn) reaction to study the low-lying level structure of 73Kr. By utilizing a bombarding energy at the Coulomb barrier, the relative cross section for this channel was enhanced to a few percent of the total reaction cross section. Levels in 73Kr were assigned based primarily upon observed neutron-gamma-gamma coincidences and upon comparisons of these newly assigned transition cross sections with those from known nuclei. C1 HEBREW UNIV JERUSALEM,RACAH INST PHYS,JERUSALEM,ISRAEL. RP MOLTZ, DM (reprint author), LAWRENCE BERKELEY LAB,CTR NUCL SCI,MS 88,BERKELEY,CA 94720, USA. NR 27 TC 5 Z9 5 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 SEP 13 PY 1993 VL 562 IS 1 BP 111 EP 120 DI 10.1016/0375-9474(93)90035-V PG 10 WC Physics, Nuclear SC Physics GA MA654 UT WOS:A1993MA65400007 ER PT J AU CAMASSA, R HOLM, DD AF CAMASSA, R HOLM, DD TI AN INTEGRABLE SHALLOW-WATER EQUATION WITH PEAKED SOLITONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID WAVE AB We derive a new completely integrable dispersive shallow water equation that is bi-Hamiltonian and thus possesses an infinite number of conservation laws in involution. The equation is obtained by using an asymptotic expansion directly in the Hamiltonian for Euler's equations in the shallow water regime. The soliton solution for this equation has a limiting form that has a discontinuity in the first derivative at its peak. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP CAMASSA, R (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 13 TC 1724 Z9 1787 U1 5 U2 40 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 SEP 13 PY 1993 VL 71 IS 11 BP 1661 EP 1664 DI 10.1103/PhysRevLett.71.1661 PG 4 WC Physics, Multidisciplinary SC Physics GA LX119 UT WOS:A1993LX11900001 ER PT J AU ABE, F ALBROW, M AMIDEI, D ANWAYWIESE, C APOLLINARI, G ARETI, H AUCHINCLOSS, P AZFAR, F AZZI, P BACCHETTA, N BADGETT, W BAILEY, MW BAO, J DEBARBARO, P BARBAROGALTIERI, A BARNES, VE BARNETT, BA BAUER, G BAUMANN, T BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENJAMIN, D BENLLOCH, J BERETVAS, A BHATTI, A BIERY, K BINKLEY, M BIRD, F BISELLO, D BLAIR, RE BLOCKER, C BODEK, A BOLOGNESI, V BOSWELL, C BOULOS, T BRANDENBURG, G BUCKLEYGEER, E BUDD, HS BURKETT, K BUSETTO, G BYONWAGNER, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CANER, A CARITHERS, W CARLSMITH, D CASTRO, A CEN, Y CERVELLI, F CHAPMAN, J CHIARELLI, G CHIKAMATSU, T CIHANGIR, S CLARK, AG COBAL, M CONTRERAS, M COOPER, J CORDELLI, M COUPAL, DP CRANE, D CUNNINGHAM, JD DANIELS, T DEJONGH, F DELLAGNELLO, S DELLORSO, M DEMORTIER, L DENBY, B DENINNO, M DERWENT, PF DEVLIN, T DICKSON, M DONE, JP DRUCKER, RB DUNN, A EINSWEILER, K ELIAS, JE ELY, R ENGELS, E ENO, S ERREDE, D ERREDE, S ETCHEGOYEN, A FAN, Q FARHAT, B FIORI, I FLAUGHER, B FOSTER, GW FRANKLIN, M FRAUTSCHI, M FREEMAN, J FRIEDMAN, J FRISCH, H FRY, A FUESS, TA FUKUI, Y FUNAKI, S GARFINKEL, AF GEER, S GERDES, DW GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GLENZINSKI, D GOLD, M GONZALEZ, J GORDON, A GOSHAW, AT GOULIANOS, K GRASSMANN, H GREWAL, A GRIECO, G GROER, L GROSSOPILCHER, C HABER, C HAHN, SR HAMILTON, R HANDLER, R HANS, RM HARA, K HARRAL, B HARRIS, RM HAUGER, SA HAUSER, J HAWK, C HEINRICH, J HENNESSY, D HOLLEBEEK, R HOLLOWAY, L HOLSCHER, A HONG, S HOUK, G HU, P HUFFMAN, BT HUGHES, R HURST, P HUTH, J HYLEN, J INCAGLI, M INCANDELA, J ISO, H JENSEN, H JESSOP, CP JOSHI, U KADEL, RW KAMON, T KANEKO, T KARDELIS, DA KASHA, H KATO, Y KEEBLE, L KENNEDY, R KEPHART, R KESTEN, P KESTENBAUM, D KEUP, RM KEUTELIAN, H KEYVAN, F KIM, DH KIM, SB KIM, SH KIM, YK KIRSCH, L KOEHN, P KONDO, K KONIGSBERG, J KOPP, S KORDAS, K KOSKA, W KOVACS, E KRASBERG, M KUHLMANN, SE KUNS, E LAASANEN, AT LAMMEL, S LAMOUREUX, JI LECOMPTE, T LEONE, S LEWIS, JD LIMON, P LINDGREN, M LISS, TM LOCKYER, N LONG, O LORETI, M LOW, EH LU, J LUCCHESI, D LUCHINI, CB LUKENS, P MAAS, P MAESHIMA, K MAGHAKIAN, A MANGANO, M MANSOUR, J MARIOTTI, M MARRINER, JP MARTIN, A MATTHEWS, JAJ MATTINGLY, R MCINTYRE, P MELESE, P MENZIONE, A MESCHI, E MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MITSUSHIO, H MIYASHITA, S MORITA, Y MOULDING, S MUELLER, J MUKHERJEE, A MULLER, T NAKAE, LF NAKANO, I NELSON, C NEUBERGER, D NEWMANHOLMES, C NODULMAN, L OGAWA, S OHL, KE OISHI, R OKUSAWA, T PAOLETTI, R PAPADIMITRIOU, V PARK, S PATRICK, J PAULETTA, G PESCARA, L PETERS, MD PHILLIPS, TJ PIACENTINO, G PILLAI, M PLUNKETT, R PONDROM, L PRODUIT, N PROUDFOOT, J PTOHOS, F PUNZI, G RAGAN, K RIMONDI, F RISTORI, L ROACHBELLINO, M ROBERTSON, WJ RODRIGO, T ROMANO, J ROSENSON, L SAKUMOTO, WK SALTZBERG, D SANSONI, A SCARPINE, V SCHINDLER, A SCHLABACH, P SCHMIDT, EE SCHMIDT, MP SCHNEIDER, O SCIACCA, G SCRIBANO, A SEGLER, S SEIDEL, S SEIYA, Y SGANOS, G SHAPIRO, M SHAW, NM SHEN, Q SHEPARD, PF SHIMOJIMA, M SHOCHET, M SIEGRIST, J SILL, A SINERVO, P SINGH, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD SONG, L SONG, T SPALDING, J SPHICAS, P SPIES, A STANCO, L STEELE, J STEFANINI, A SULLIVAN, G SUMOROK, K SWARTZ, RL TAKAHASHI, T TAKIKAWA, K TANNENBAUM, B TARTARELLI, F TERAMOTO, Y TETHER, S THERIOT, D THOMAS, J THUN, R TIMKO, M TIPTON, P TITOV, A TKACZYK, S TOLLESTRUP, A TONNISON, J TSENG, J TURCOTTE, M TURINI, N UEMURA, N UKEGAWA, F VEJCIK, S VONDRACEK, M WAGNER, RG WAGNER, RL WAINER, N WALKER, RC WANG, J WANG, QF WARBURTON, A WATTS, G WATTS, T WEBB, R WENDT, C WENZEL, H WESTER, WC WESTHUSING, T WICKLUND, AB WICKLUND, E WILKINSON, R WILLIAMS, HH WINER, BL WOLINSKI, J WU, DY WU, X WYSS, J YAGIL, A YAO, W YASUOKA, K YE, Y YEH, GP YIN, M YOH, J YOSHIDA, T YOVANOVITCH, D YU, I YUN, JC ZANETTI, A ZETTI, F ZHANG, S ZHANG, W ZUCCHELLI, S AF ABE, F ALBROW, M AMIDEI, D ANWAYWIESE, C APOLLINARI, G ARETI, H AUCHINCLOSS, P AZFAR, F AZZI, P BACCHETTA, N BADGETT, W BAILEY, MW BAO, J DEBARBARO, P BARBAROGALTIERI, A BARNES, VE BARNETT, BA BAUER, G BAUMANN, T BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENJAMIN, D BENLLOCH, J BERETVAS, A BHATTI, A BIERY, K BINKLEY, M BIRD, F BISELLO, D BLAIR, RE BLOCKER, C BODEK, A BOLOGNESI, V BOSWELL, C BOULOS, T BRANDENBURG, G BUCKLEYGEER, E BUDD, HS BURKETT, K BUSETTO, G BYONWAGNER, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CANER, A CARITHERS, W CARLSMITH, D CASTRO, A CEN, Y CERVELLI, F CHAPMAN, J CHIARELLI, G CHIKAMATSU, T CIHANGIR, S CLARK, AG COBAL, M CONTRERAS, M COOPER, J CORDELLI, M COUPAL, DP CRANE, D CUNNINGHAM, JD DANIELS, T DEJONGH, F DELLAGNELLO, S DELLORSO, M DEMORTIER, L DENBY, B DENINNO, M DERWENT, PF DEVLIN, T DICKSON, M DONE, JP DRUCKER, RB DUNN, A EINSWEILER, K ELIAS, JE ELY, R ENGELS, E ENO, S ERREDE, D ERREDE, S ETCHEGOYEN, A FAN, Q FARHAT, B FIORI, I FLAUGHER, B FOSTER, GW FRANKLIN, M FRAUTSCHI, M FREEMAN, J FRIEDMAN, J FRISCH, H FRY, A FUESS, TA FUKUI, Y FUNAKI, S GARFINKEL, AF GEER, S GERDES, DW GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GLENZINSKI, D GOLD, M GONZALEZ, J GORDON, A GOSHAW, AT GOULIANOS, K GRASSMANN, H GREWAL, A GRIECO, G GROER, L GROSSOPILCHER, C HABER, C HAHN, SR HAMILTON, R HANDLER, R HANS, RM HARA, K HARRAL, B HARRIS, RM HAUGER, SA HAUSER, J HAWK, C HEINRICH, J HENNESSY, D HOLLEBEEK, R HOLLOWAY, L HOLSCHER, A HONG, S HOUK, G HU, P HUFFMAN, BT HUGHES, R HURST, P HUTH, J HYLEN, J INCAGLI, M INCANDELA, J ISO, H JENSEN, H JESSOP, CP JOSHI, U KADEL, RW KAMON, T KANEKO, T KARDELIS, DA KASHA, H KATO, Y KEEBLE, L KENNEDY, R KEPHART, R KESTEN, P KESTENBAUM, D KEUP, RM KEUTELIAN, H KEYVAN, F KIM, DH KIM, SB KIM, SH KIM, YK KIRSCH, L KOEHN, P KONDO, K KONIGSBERG, J KOPP, S KORDAS, K KOSKA, W KOVACS, E KRASBERG, M KUHLMANN, SE KUNS, E LAASANEN, AT LAMMEL, S LAMOUREUX, JI LECOMPTE, T LEONE, S LEWIS, JD LIMON, P LINDGREN, M LISS, TM LOCKYER, N LONG, O LORETI, M LOW, EH LU, J LUCCHESI, D LUCHINI, CB LUKENS, P MAAS, P MAESHIMA, K MAGHAKIAN, A MANGANO, M MANSOUR, J MARIOTTI, M MARRINER, JP MARTIN, A MATTHEWS, JAJ MATTINGLY, R MCINTYRE, P MELESE, P MENZIONE, A MESCHI, E MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MITSUSHIO, H MIYASHITA, S MORITA, Y MOULDING, S MUELLER, J MUKHERJEE, A MULLER, T NAKAE, LF NAKANO, I NELSON, C NEUBERGER, D NEWMANHOLMES, C NODULMAN, L OGAWA, S OHL, KE OISHI, R OKUSAWA, T PAOLETTI, R PAPADIMITRIOU, V PARK, S PATRICK, J PAULETTA, G PESCARA, L PETERS, MD PHILLIPS, TJ PIACENTINO, G PILLAI, M PLUNKETT, R PONDROM, L PRODUIT, N PROUDFOOT, J PTOHOS, F PUNZI, G RAGAN, K RIMONDI, F RISTORI, L ROACHBELLINO, M ROBERTSON, WJ RODRIGO, T ROMANO, J ROSENSON, L SAKUMOTO, WK SALTZBERG, D SANSONI, A SCARPINE, V SCHINDLER, A SCHLABACH, P SCHMIDT, EE SCHMIDT, MP SCHNEIDER, O SCIACCA, G SCRIBANO, A SEGLER, S SEIDEL, S SEIYA, Y SGANOS, G SHAPIRO, M SHAW, NM SHEN, Q SHEPARD, PF SHIMOJIMA, M SHOCHET, M SIEGRIST, J SILL, A SINERVO, P SINGH, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD SONG, L SONG, T SPALDING, J SPHICAS, P SPIES, A STANCO, L STEELE, J STEFANINI, A SULLIVAN, G SUMOROK, K SWARTZ, RL TAKAHASHI, T TAKIKAWA, K TANNENBAUM, B TARTARELLI, F TERAMOTO, Y TETHER, S THERIOT, D THOMAS, J THUN, R TIMKO, M TIPTON, P TITOV, A TKACZYK, S TOLLESTRUP, A TONNISON, J TSENG, J TURCOTTE, M TURINI, N UEMURA, N UKEGAWA, F VEJCIK, S VONDRACEK, M WAGNER, RG WAGNER, RL WAINER, N WALKER, RC WANG, J WANG, QF WARBURTON, A WATTS, G WATTS, T WEBB, R WENDT, C WENZEL, H WESTER, WC WESTHUSING, T WICKLUND, AB WICKLUND, E WILKINSON, R WILLIAMS, HH WINER, BL WOLINSKI, J WU, DY WU, X WYSS, J YAGIL, A YAO, W YASUOKA, K YE, Y YEH, GP YIN, M YOH, J YOSHIDA, T YOVANOVITCH, D YU, I YUN, JC ZANETTI, A ZETTI, F ZHANG, S ZHANG, W ZUCCHELLI, S TI OBSERVATION OF THE DECAY B(S)0-]J-PSI-PHI IN (P)OVER-BAR-P COLLISIONS AT ROOT-S = 1.8 TEV SO PHYSICAL REVIEW LETTERS LA English DT Article ID HADRONIC COLLISIONS; CROSS-SECTION; MESON; QUARKS; BS AB This Letter reports the observation and mass measurement of fully reconstructed B(s)0 mesons through the decay chain B(s)0 --> J/psiphi, J/psi --> mu+mu-, phi --> K+K- using data obtained at the Collider Detector at Fermilab in ppBAR collisions at square-root s = 1.8 TeV. A signal of 14.0 +/- 4.7 events is observed. Comparison of the B(s)0 signal with the kinematically similar decays B+ --> J/psiK+ and B0 --> J/psiK*(892)0 is presented. The mass of the B(s)0 meson is determined to be 5383.3 +/- 4.5 (stat) +/- 5.0 (syst) MeV/c2. C1 BRANDEIS UNIV,WALTHAM,MA 02254. UNIV BOLOGNA,IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60637. DUKE UNIV,DURHAM,NC 27708. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV ILLINOIS,URBANA,IL 61801. MCGILL UNIV,INST PARTICLE PHYS,MONTREAL H3A 2T8,QUEBEC,CANADA. UNIV TORONTO,TORONTO M5S 1A7,ONTARIO,CANADA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. KEK,NATL LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 305,JAPAN. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. OSAKA CITY UNIV,OSAKA 558,JAPAN. UNIV PADUA,IST NAZL FIS NUCL,I-35131 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PITTSBURGH,PITTSBURGH,PA 15260. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. RUTGERS UNIV,PISCATAWAY,NJ 08854. ROCKEFELLER UNIV,NEW YORK,NY 10021. SUPERCOND SUPER COLLIDER LAB,DALLAS,TX 75237. TEXAS A&M UNIV SYST,COLL STN,TX 77843. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. YALE UNIV,NEW HAVEN,CT 06511. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. RP ABE, F (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Chiarelli, Giorgio/E-8953-2012; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Warburton, Andreas/N-8028-2013; Kim, Soo-Bong/B-7061-2014 OI Chiarelli, Giorgio/0000-0001-9851-4816; Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Warburton, Andreas/0000-0002-2298-7315; NR 20 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 13 PY 1993 VL 71 IS 11 BP 1685 EP 1689 DI 10.1103/PhysRevLett.71.1685 PG 5 WC Physics, Multidisciplinary SC Physics GA LX119 UT WOS:A1993LX11900007 ER PT J AU MENESES, GD BRESCANSIN, LM LEE, MT MICHELIN, SE MACHADO, LE CSANAK, G AF MENESES, GD BRESCANSIN, LM LEE, MT MICHELIN, SE MACHADO, LE CSANAK, G TI STOKES PARAMETERS AND ROVIBRATIONALLY RESOLVED CROSS-SECTIONS FOR THE X1-SIGMA-G(+) (UPSILON=0, N=1) -]D(3)PI(U)(-) (UPSILON=0, N=1) EXCITATION IN H-2 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-IMPACT EXCITATION; PHOTON COINCIDENCE; ANGULAR-CORRELATION; STATES; HELIUM; GASES AB We report for the first time the calculation of Stokes parameters and state-to-state rovibrationally resolved differential cross sections for the excitation X1SIGMA(g)+(v = 0, N = 1) --> d3PI(u)- (v = 0, N = 1) in H-2 by electron impact at 25 eV. Comparison with the only available experimental data is encouraging. C1 UNIV FED SAO CARLOS,DEPT QUIM,BR-13560 SAO CARLOS,SP,BRAZIL. UNIV FED SANTA CATARINA,DEPT FIS,BR-88000 FLORIANOPOLI,SC,BRAZIL. UNIV FED SAO CARLOS,DEPT FIS,BR-13560 SAO CARLOS,SP,BRAZIL. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP MENESES, GD (reprint author), UNIV ESTADUAL CAMPINAS,INST FIS GLEB WATAGHIN,BR-13081 CAMPINAS,SP,BRAZIL. RI Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 24 TC 5 Z9 5 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 SEP 13 PY 1993 VL 71 IS 11 BP 1701 EP 1704 DI 10.1103/PhysRevLett.71.1701 PG 4 WC Physics, Multidisciplinary SC Physics GA LX119 UT WOS:A1993LX11900011 ER PT J AU JESSON, DE PENNYCOOK, SJ BARIBEAU, JM HOUGHTON, DC AF JESSON, DE PENNYCOOK, SJ BARIBEAU, JM HOUGHTON, DC TI DIRECT IMAGING OF SURFACE CUSP EVOLUTION DURING STRAINED-LAYER EPITAXY AND IMPLICATIONS FOR STRAIN RELAXATION SO PHYSICAL REVIEW LETTERS LA English DT Article ID GROWTH; NUCLEATION; MISFIT; THICKNESS; CRYSTALS; SI(100) AB We have directly imaged the evolution of surface cusps during strained-layer epitaxy. The cusps arise naturally as a result of gradients in the surface chemical potential. High stress concentrations at the cusp tip have important implications for strain relaxation in the film via dislocation nucleation. C1 NATL RES COUNCIL CANADA,INST MICROSTRUCT SCI,OTTAWA K1A 0R6,ONTARIO,CANADA. RP JESSON, DE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. OI Jesson, David/0000-0003-0897-1445 NR 22 TC 215 Z9 217 U1 2 U2 20 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 SEP 13 PY 1993 VL 71 IS 11 BP 1744 EP 1747 DI 10.1103/PhysRevLett.71.1744 PG 4 WC Physics, Multidisciplinary SC Physics GA LX119 UT WOS:A1993LX11900022 ER PT J AU OMELCHENKO, YA PUSHKAREV, AN RUBENCHIK, AM AF OMELCHENKO, YA PUSHKAREV, AN RUBENCHIK, AM TI A NONCOLLISIONAL MECHANISM FOR PLASMA SPECIES SEPARATION SO PHYSICS LETTERS A LA English DT Article AB A noncollisional mechanism for the separation of ion species moving through a plasma is proposed. The results of a numerical simulation prove the possibility of anomalous quick spatial separation of ion species on the scale of about 200 Debye radii. C1 RUSSIAN ACAD SCI,SCI COUNCIL COMPLEX PROBLEMS CYBERNET,MOSCOW 117333,RUSSIA. UNIV CALIF DAVIS,PLASMA PHYS RES INST,DAVIS,CA 95616. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RUSSIA ACAD SCI,INST AUTOMAT & ELECTROMETRY,NOVOSIBIRSK 630090,RUSSIA. RP OMELCHENKO, YA (reprint author), RUSSIAN ACAD SCI,SPACE RES INST,MOSCOW 117810,RUSSIA. RI Pushkarev, Andrei/I-8290-2016 OI Pushkarev, Andrei/0000-0001-9310-5888 NR 4 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD SEP 13 PY 1993 VL 180 IS 4-5 BP 357 EP 360 DI 10.1016/0375-9601(93)91191-7 PG 4 WC Physics, Multidisciplinary SC Physics GA LX869 UT WOS:A1993LX86900011 ER PT J AU HORWITZ, EP CHIARIZIA, R DIETZ, ML DIAMOND, H AF HORWITZ, EP CHIARIZIA, R DIETZ, ML DIAMOND, H TI SEPARATION AND PRECONCENTRATION OF ACTINIDES FROM ACIDIC MEDIA BY EXTRACTION CHROMATOGRAPHY SO ANALYTICA CHIMICA ACTA LA English DT Article DE CHROMATOGRAPHY; ACTINIDES; EXTRACTION; PRECONCENTRATION ID NITRIC-ACID; STRONTIUM AB A systematic examination of the effect of nitric and hydrochloric acid concentrations and of macro levels of selected elements on the sorption of actinide ions by a novel extraction chromatographic resin comprised of a solution of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tri-n-butyl phosphate supported on an inert polymeric substrate is described. Actinide sorption is demonstrated to be most efficient at high ( > 1 M) nitric acid concentrations, although tetra- and hexavalent actinides are strongly retained even from dilute (e.g., 0.05 M) nitric acid solutions. Macro concentrations of several common anions (e.g., PO43- and SO42-) or complexing agents (e.g., oxalic acid) are shown not to adversely affect the sorption of trivalent actinides, while reducing the sorption of tetravalents. Such effects, together with oxidation state adjustments, are shown to provide a basis for the sequential elution of individual actinides and for actinide isolation from environmental and biological matrices. C1 ARGONNE NATL LAB,DEPT ENVIRONM SAFETY & HLTH,ARGONNE,IL 60439. RP HORWITZ, EP (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 19 TC 314 Z9 316 U1 9 U2 48 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD SEP 10 PY 1993 VL 281 IS 2 BP 361 EP 372 DI 10.1016/0003-2670(93)85194-O PG 12 WC Chemistry, Analytical SC Chemistry GA LZ181 UT WOS:A1993LZ18100018 ER PT J AU PRINCE, JM HILDEBRAND, BP AF PRINCE, JM HILDEBRAND, BP TI LOW-FREQUENCY ELECTROMAGNETIC (EDDY-CURRENT) HOLOGRAPHY FOR IMAGING IN CONDUCTORS SO APPLIED OPTICS LA English DT Article AB Typical eddy-current system test data consist of the values of the system's probe impedance. The wave theory that links the phase response of the eddy-current probe impedance to the defect location relative to the probe is presented. The technique of phase multiplying the diffraction-limited hologram generated from the probe impedance is discussed. The effects and limitations of this technique are illustrated with a mathematical model of the eddy-current probe. Experimental data are presented that confirm the theoretical analysis and illustrate the ability to focus eddy-current holographic data by using backward wave propagation. RP PRINCE, JM (reprint author), PACIFIC NW LAB, CTR APPL PHYS, MS K2-28, BATTELLE BLVD, RICHLAND, WA 99352 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD SEP 10 PY 1993 VL 32 IS 26 BP 4960 EP 4971 PG 12 WC Optics SC Optics GA LW372 UT WOS:A1993LW37200002 PM 20856298 ER PT J AU VANBREUGEL, WJM DEY, A AF VANBREUGEL, WJM DEY, A TI INDUCED STAR-FORMATION IN A RADIO LOBE OF 3C-285 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (3C-285); RADIO CONTINUUM, GALAXIES; STARS, FORMATION ID H-II-REGIONS; HIGH-REDSHIFT; REPRESENTATIVE SAMPLE; ELECTRON-SCATTERING; IMAGING POLARIMETRY; SPECTRAL EVOLUTION; OPTICAL-EMISSION; CYGNUS-A; GALAXIES; ALIGNMENT AB We report the discovery of a blue, star-forming region in the eastern lobe of the nearby (z = 0.0794), classical double-lobed radio galaxy 3C 285. This region is elongated along the radio source axis, and its optical line emission, and possibly its optical continuum emission, appear to be edge-brightened on the side facing the nucleus of 3C 285. We propose that the star formation in this region was triggered by the passage of the radio lobe through a region of dense gas in the intergalactic medium. Our observations add support to models in which powerful radio sources induce star formation through the compression of dense ambient material and are also in agreement with such an interpretation for the alignment effect observed in high-redshift radio galaxies. C1 UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. RP LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, MS L-413, LIVERMORE, CA 94550 USA. NR 64 TC 64 Z9 64 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1993 VL 414 IS 2 BP 563 EP 572 DI 10.1086/173103 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LU946 UT WOS:A1993LU94600017 ER PT J AU GENTILE, NA AUFDERHEIDE, MB MATHEWS, GJ SWESTY, FD FULLER, GM AF GENTILE, NA AUFDERHEIDE, MB MATHEWS, GJ SWESTY, FD FULLER, GM TI THE QCD PHASE-TRANSITION AND SUPERNOVA CORE COLLAPSE SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, INTERIORS; STARS, NEUTRON; SUPERNOVAE, GENERAL ID GAUGE VECTOR-MESONS; GROUND-STATE ENERGY; FINITE TEMPERATURE; SUPERDENSE MATTER; DENSE MATTER; PRIMORDIAL NUCLEOSYNTHESIS; NEUTRINO TRANSPORT; STRANGE MATTER; II SUPERNOVAE; EQUATION AB We examine the implications for stellar core collapse of a phase transition occurring at densities of a few times nuclear matter density. We use a schematic equation of state motivated by the Skyrme model low-energy approximation to QCD, which contains a phase transition corresponding to the conversion of bulk nuclear matter to a chirally symmetric quark-gluon phase. We analyze the stability of the core against gravitational collapse with respect to the amount of gravitational binding energy released and the kinematic energy of the shock. We show that a first-order phase transition actually gives rise to two shocks which quickly coalesce. More importantly, we show that there are significant differences in the evolution of cores with or without first- or second-order phase transitions which may eventually lead to observational signatures in the neutrino signal. C1 SUNY,DEPT PHYS,STONY BROOK,NY 11794. SUNY,DEPT EARTH & SPACE SCI,STONY BROOK,NY 11794. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. RP GENTILE, NA (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 60 TC 62 Z9 64 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 SEP 10 PY 1993 VL 414 IS 2 BP 701 EP 711 DI 10.1086/173116 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LU946 UT WOS:A1993LU94600030 ER PT J AU WARREN, JK VALLERGA, JV MAUCHE, CW MUKAI, K SIEGMUND, OHW AF WARREN, JK VALLERGA, JV MAUCHE, CW MUKAI, K SIEGMUND, OHW TI EXTREME-ULTRAVIOLET EXPLORER OBSERVATIONS OF THE MAGNETIC CATACLYSMIC VARIABLE RE 1938-461 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; NOVAE, CATACLYSMIC VARIABLES; STARS, INDIVIDUAL (RE 1938-461); STARS, MAGNETIC FIELDS; X-RAYS, STARS ID AM HERCULIS; RADIO-EMISSION AB The magnetic cataclysmic variable RE 1938-461 was observed by the Extreme Ultraviolet Explorer (EUVE) Deep Survey instrument on 1992 July 8-9 during in-orbit calibration. It was detected in the Lexan/boron (65-190 angstrom) band, with a quiescent count rate of 0.0062 +/- 0.0017 s-1, and was not detected in the aluminum/carbon (160-360 angstrom) band. The Lexan/boron count rate is lower than the corresponding ROSAT wide-field camera Lexan/boron count rate. This is consistent with the fact that the source was in a low state during an optical observation performed just after the EUVE observation, whereas it was in an optical high state during the ROSAT observation. The quiescent count rates are consistent with a virtual cessation of accretion. Two transient events lasting approximately 1 hr occurred during the Lexan/boron pointing, the second at a count rate of 0.050 +/- 0.006 s-1. This appears to be the first detection of an EUV transient during the low state of a magnetic cataclysmic variable. We propose two possible explanations for the transient events. (1) They may have been caused by intermittent accretion of dense filaments of matter, formed by an instability at the second star surface, which impact and heat the white dwarf photosphere, causing it to emit EUV radiation. For an assumed blackbody temperature of 20-50 eV and an interstellar column density of 10(20) cm-2, the luminosity of the second transient is approximately 10(32) (d/300 pc)2 ergs s-1, and the fractional emitting area of the white dwarf is approximately 6 x 10(-5) (d/300 pc)2 for a 0.7 M. white dwarf. (2) Given the high rotation rate of the secondary and the possibility that the secondary is magnetically active, it is possible that these transients are the EUV component of magnetic flares. For an assumed thermal plasma with a temperature of 10(6)-10(8) K and an interstellar column density of 10(20) cm-2, the luminosity of the second transient is approximately 10(33) (d/300 pc)2 ergs s-1 and the emission measure is approximately 10(55)-10(56) (d/300 pc)2 cm-3. We note that a magnetic flare or a coronal mass ejection may be the source of the intermittent accretion enhancements of the first scenario. C1 UNIV CALIF BERKELEY,CTR EUV ASTROPHYS,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP WARREN, JK (reprint author), UNIV CALIF BERKELEY,SPACE SCI LAB,EXPTL ASTROPHYS GRP,BERKELEY,CA 94720, USA. NR 21 TC 16 Z9 16 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 SEP 10 PY 1993 VL 414 IS 2 BP L69 EP L72 DI 10.1086/186998 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LU947 UT WOS:A1993LU94700006 ER PT J AU ACKERMAN, JP SETTLE, JL AF ACKERMAN, JP SETTLE, JL TI DISTRIBUTION OF PLUTONIUM, AMERICIUM, AND SEVERAL RARE-EARTH FISSION-PRODUCT ELEMENTS BETWEEN LIQUID CADMIUM AND LICL-KCL EUTECTIC SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article ID SALT AB Separation factors were measured that describe the partition between molten cadmium and molten LiCl-KCl eutectic of plutonium, americium, praseodymium, neodymium, cerium, lanthanum, gadolinium, dysprosium, and yttrium. The temperature range was 753-788 K, and the range of concentrations was that allowed by the sensitivity of the chemical analysis methods. Mean separation factors were derived for Am-Pu, Nd-Am, Nd-Pu, Nd-Pr, Gd-La, Dy-La, La-Ce, La-Nd, Y-La, and Y-Nd. Where previously published data were available, agreement was good. For convenience, the following series of separation factors relative to plutonium was derived by combining the measured separation factors: Pu, 1.00 (basis); Am, 1.54; Pr, 22.9; Nd, 23.4; Ce, 26; La, 70; Gd, 77; Dy, 270; Y, 3000. These data are used in calculating the distribution of the actinide and rare earth elements in the pyrochemical reprocessing of spent fuel from the Integral Fast Reactor. RP ACKERMAN, JP (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 12 TC 31 Z9 31 U1 0 U2 7 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 SEP 10 PY 1993 VL 199 IS 1-2 BP 77 EP 84 DI 10.1016/0925-8388(93)90430-U PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA LV152 UT WOS:A1993LV15200012 ER PT J AU SOREY, ML KENNEDY, BM EVANS, WC FARRAR, CD SUEMNICHT, GA AF SOREY, ML KENNEDY, BM EVANS, WC FARRAR, CD SUEMNICHT, GA TI HELIUM ISOTOPE AND GAS-DISCHARGE VARIATIONS ASSOCIATED WITH CRUSTAL UNREST IN LONG VALLEY CALDERA, CALIFORNIA, 1989-1992 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DEL-RUIZ VOLCANO; HYDROTHERMAL SYSTEM; NOBLE-GASES; EARTHQUAKE SWARM; RHYOLITIC MAGMA; RATIOS; CARBON; YELLOWSTONE; COLOMBIA; ERUPTION AB The onset of anomalous seismic activity in 1989 beneath Mammoth Mountain on the southwestern rim of the Long Valley caldera, California, was followed within approximately 4 months by a large increase in He-3/He-4 in vapor discharged from a fumarole on the north side of the mountain. The helium isotopic ratio at this vent rose to a maximum of 6.7 R(A) in July 1990 and subsequently declined to values near 5 R(A). Potential sources of the He-3-rich vapors include degassing of fresh magma, degassing from fresh surfaces generated in newly fractured igneous rocks, and volatile release from a He-3-rich ps chamber situated above previously emplaced intrusives. The magnitude of the increase in helium isotopic composition (from 3.8 to 6.7 R(A)), the persistence of relatively high values (>5 R(A)) over a period of 3 years, the increase in the flux of total He relative to gases in air-saturated water, and the increases in the rates of discharge of steam and gas from this fumarole indicate that magmatic intrusion did in fact begin in 1989 beneath Mammoth Mountain. Seismic activity and limited measurements of extensional deformation at the surface suggest that the depth of intrusion may be as shallow as 2 km, consistent with the prompt appearance of increased He-3/He-4 ratios in the fumarolic ps, and that the intrusive process may have persisted for approximately 1 year. In contrast, a similar combination of magmatic intrusion and anomalous seismic activity beneath the resurgent dome-south moat region during the 1989-1991 period resulted in at most relatively small changes in He-3/He-4 in fumarolic discharge at the southern edge of the resurgent dome. The more subdued response may result from a combination of greater intrusive depths and greater dilution of He-3-rich inputs to thermal fluid reservoirs in the shallow hydrothermal system in this area compared with Mammoth Mountain. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP SOREY, ML (reprint author), US GEOL SURVEY,MS 439,345 MIDDLEFIELD RD,MENLO PK,CA 94025, USA. RI Evans, William/J-4283-2012 NR 59 TC 58 Z9 61 U1 0 U2 4 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 SEP 10 PY 1993 VL 98 IS B9 BP 15871 EP 15889 DI 10.1029/93JB00703 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LW847 UT WOS:A1993LW84700010 ER PT J AU BLACIC, JD AF BLACIC, JD TI HYDRATION SWELLING EFFECTS ON TIME-DEPENDENT DEFORMATION OF ZEOLITIZED TUFF SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID YUCCA MOUNTAIN; NEVADA AB Long-duration creep deformation experiments were performed on zeolitized tuffs from Yucca Mountain, Nevada, at temperatures of 35-degrees-75-degrees-C, confining pressure of 5 MPa, and water pore pressure of 0.1 MPa. The test samples were initially loaded to a relatively small fraction of the uniaxial compressive failure stress, and allowed to creep; then the stress was increased periodically until creep failure occurred. The strain versus time creep curves exhibit the classical phenomenological phases of primary, secondary, and tertiary creep analogous to those for ductile metals, although the tuffs deform by dilation microcracking and fail by brittle fracture. Mechanical ''steady state'' or secondary creep strain rates as low as 1 x 10(-10) s-1 were observed in the tests. Tertiary creep axial failure strains averaged about 6 x 10(-3). The early, water saturation phases of the tests are characterized by large hydration swelling strains associated with water absorption by the zeolite minerals in the tuffs. The hydration was often incomplete after one month of immersion, and slow, continued hydration affected the creep curves so that the samples appeared to lengthen against axial differential stresses as high as 55 MPa. This strong chemical-mechanical coupling suggests that in situ hydration state changes could generate stresses of similar magnitude. RP BLACIC, JD (reprint author), LOS ALAMOS NATL LAB,GEOL & GEOCHEM GRP,MS D462,LOS ALAMOS,NM 87545, USA. NR 18 TC 5 Z9 5 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 SEP 10 PY 1993 VL 98 IS B9 BP 15909 EP 15917 DI 10.1029/93JB00696 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LW847 UT WOS:A1993LW84700013 ER PT J AU ROUTBORT, JL AF ROUTBORT, JL TI TRACER DIFFUSION OF OXYGEN IN NDBA2CU3O7-DELTA SO PHYSICA C LA English DT Article ID INTERNAL-FRICTION; YBA2CU3O7-DELTA; RELAXATION AB Tracer diffusion measurements of O-18 in NdBa2Cu3O7-delta have been performed at 400 and 500-degrees-C at an oxygen partial pressure of one atmosphere. Depth profiles were determined by secondary ion mass spectrometry. The measured diffusion coefficients are quite near those measured for O-18 tracer diffusion in YBa2Cu3O7-delta. Therefore, it does not appear that the temperature shift in the internal friction peak as larger ions are substituted for yttrium is the result of enhanced oxygen tracer diffusion as reported by Tallon and Mellander (Science 258 (1992) 781.) RP ROUTBORT, JL (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 10 TC 7 Z9 7 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 SEP 10 PY 1993 VL 214 IS 3-4 BP 408 EP 412 DI 10.1016/0921-4534(93)90845-H PG 5 WC Physics, Applied SC Physics GA LX580 UT WOS:A1993LX58000026 ER PT J AU JORDAN, TH PUSTER, P GLATZMAIER, GA TACKLEY, PJ AF JORDAN, TH PUSTER, P GLATZMAIER, GA TACKLEY, PJ TI COMPARISONS BETWEEN SEISMIC EARTH STRUCTURES AND MANTLE FLOW MODELS BASED ON RADIAL CORRELATION-FUNCTIONS SO SCIENCE LA English DT Article ID LONG-WAVELENGTH HETEROGENEITY; ASPHERICAL STRUCTURE; PHASE-TRANSITIONS; NORTHWEST PACIFIC; LITHOSPHERIC SLAB; ISLAND ARCS; CONVECTION; TEMPERATURE; GENERATION; BENEATH AB Three-dimensional numerical simulations were conducted of mantle convection in which flow through the transition zone is impeded by either a strong chemical change or an endothermic phase change. The temperature fields obtained from these models display a well-defined minimum in the vertical correlation length at or near the radius where the barrier is imposed, even when the fields were filtered to low angular and radial resolutions. However, evidence for such a feature is lacking in the shear-velocity models derived by seismic tomography. This comparison suggests that any stratification induced by phase or chemical changes across the mid-mantle transition zone has a relatively small effect on the large-scale circulation of mantle material. C1 CALTECH,SEISMOL LAB,PASADENA,CA 91125. LOS ALAMOS NATL LAB,DIV EARTH & ENVIRONM SCI,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,INST GEOPHYS & PLANETARY PHYS,LOS ALAMOS,NM 87545. RP JORDAN, TH (reprint author), MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139, USA. RI Tackley, Paul/D-8155-2016 OI Tackley, Paul/0000-0003-4878-621X NR 57 TC 54 Z9 54 U1 1 U2 5 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 10 PY 1993 VL 261 IS 5127 BP 1427 EP 1431 DI 10.1126/science.261.5127.1427 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LW549 UT WOS:A1993LW54900026 PM 17745353 ER PT J AU GILMAN, JJ AF GILMAN, JJ TI WHY SILICON IS HARD SO SCIENCE LA English DT Article AB Compared with pure metals and ionic salts, covalent solids such as silicon are hard and brittle because dislocations do not move in them except at high temperatures. A satisfactory explanation for this behavior has been lacking in spite of its great importance for the mechanics of materials and structures. It is shown here that the critical atomic process leading to the observed brittleness is analogous to a chemical substitution reaction. Analysis of this analogy with the aid of a correlation diagram yields the observed high resistive stress and high activation energy. When a kink on a dislocation line moves, it breaks the atomic bonding symmetry, a forbidden process. RP GILMAN, JJ (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 14 TC 55 Z9 56 U1 1 U2 18 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 10 PY 1993 VL 261 IS 5127 BP 1436 EP 1439 DI 10.1126/science.261.5127.1436 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LW549 UT WOS:A1993LW54900029 PM 17745356 ER PT J AU SCHNEIDER, D BRIERE, MA CLARK, MW MCDONALD, J BIERSACK, J SIEKHAUS, W AF SCHNEIDER, D BRIERE, MA CLARK, MW MCDONALD, J BIERSACK, J SIEKHAUS, W TI ATOMIC DISPLACEMENT DUE TO THE ELECTROSTATIC POTENTIAL-ENERGY OF VERY HIGHLY-CHARGED IONS AT SOLID-SURFACES SO SURFACE SCIENCE LA English DT Article ID TRAP AB Unambiguous evidence of a new radiation effect is presented based upon the occurrence of single ion defects which are created through the interaction of the Coulombic potential of slow highly charged ions (e.g., Xe44+ and U70+) and the surface region of solid insulating surfaces (i.e. mica). In the cases studied, the kinetic energy of the ions is some 300 to 500 keV (approximately 2.2 keV/u), while the energy associated with the electrostatic potential of the incident ions approaches 200 keV. Defect production in mica has been investigated as a function of incident ion charge, using an atomic force microscope. The volume of ''blister-like'' defects has been found to be proportional to the incident ion charge. These cases are compared to those of slow singly charged (Xe+) and fast (MeV) Xe17+ ions. Similar defects have been found for Xe44+ ions incident on other insulators such as Lexan and silica glass. C1 HAHN MEITNER INST BERLIN GMBH,W-1000 BERLIN 39,GERMANY. RP SCHNEIDER, D (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 41 Z9 42 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 SEP 10 PY 1993 VL 294 IS 3 BP 403 EP 408 DI 10.1016/0039-6028(93)90125-4 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LX599 UT WOS:A1993LX59900024 ER PT J AU LIN, MC HE, YS MELIUS, CF AF LIN, MC HE, YS MELIUS, CF TI THEORETICAL ASPECTS OF PRODUCT FORMATION FROM THE NCO+NO REACTION SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID KINETICS; RADICALS; NO; COMBUSTION; REDUCTION; MECHANISM AB The reaction of NCO with NO, an important elementary process involved in the reduction of NO(x) by HNCO, has been studied theoretically using the BAC-MP4 technique in conjunction with RRKM calculations. The computed molecular structures and thermochemical data for various intermediates and transition states suggest that the reaction takes place primarily via the singlet, ground electronic state OCNNO molecule according to the following mechanism: (step a) NCO + NO double-line arrow pointing left and right 1OCNNO --> N2O + CO; (step b) NCO + NO double-line arrow pointing left and right 1OCNNO --> c-OCNNO- --> N2 + CO2. The formation of N2O + CO occurs by the fragmentation of the singlet OCNNO intermediate step (a), whereas the production of N2 + CO2 by cyclization-fragmentation occurs via step b. The tight transition states leading to the formation of these products, coupled with the loose entrance channel, give rise to the experimentally observed strong negative temperature dependence which can be quantitatively accounted for by the results of RRKM calculations based on the BAC-MP4 data. The experimentally measured product branching ratio for channels a and b could be accounted for theoretically by lowering the calculated energy barrier for step a by 3.6 kcal/mol, corresponding to about 15% of the barrier height. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94552. RP LIN, MC (reprint author), EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322, USA. NR 22 TC 39 Z9 39 U1 1 U2 2 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 SEP 9 PY 1993 VL 97 IS 36 BP 9124 EP 9128 DI 10.1021/j100138a010 PG 5 WC Chemistry, Physical SC Chemistry GA LX923 UT WOS:A1993LX92300010 ER PT J AU GRIFFITHS, JM BELL, AT REIMER, JA AF GRIFFITHS, JM BELL, AT REIMER, JA TI MAGNETIC-RESONANCE STUDIES OF ETHENE ADSORPTION ON ALUMINA-SUPPORTED PLATINUM SURFACES SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SOLID-STATE NMR; ETHYLENE ADSORPTION; CRYSTAL-SURFACES; METAL-SURFACES; KNIGHT-SHIFT; H-2 NMR; CATALYSTS; SPECTROSCOPY; DECOMPOSITION; PT(111) AB Carbon-13 and deuterium magnetic resonance data for ethene adsorbed on high dispersion, alumina-supported platinum surfaces were obtained after adsorption at various temperatures and thermal treatments. Ethene is found to adsorb on 5% Pt/Al2O3 at low temperature in a pi-bonded form that yields a single carbon line shape at 70 ppm. Upon warming to room temperature, this species is partially converted to ethylidene and a second adsorbate, which has two protonated carbons that yield a single carbon line shape at 130 ppm. At 323 K, the predominant species on this catalyst is ethylidene, in contrast to observations reported for single-crystal and low dispersion metal-supported catalysts. Ethylidene appears to decompose into methane gas and surface carbon. C1 LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. OI Bell, Alexis/0000-0002-5738-4645 NR 58 TC 7 Z9 7 U1 0 U2 2 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 SEP 9 PY 1993 VL 97 IS 36 BP 9161 EP 9169 DI 10.1021/j100138a016 PG 9 WC Chemistry, Physical SC Chemistry GA LX923 UT WOS:A1993LX92300016 ER PT J AU BERUTO, D SEARCY, AW BOTTER, R GIORDANI, M AF BERUTO, D SEARCY, AW BOTTER, R GIORDANI, M TI THERMODYNAMICS AND KINETICS OF H2O(V) CHEMISORPTION AND SOLUBILITY IN NANOMETRIC AND SINGLE-CRYSTAL MGO PARTICLES DURING SINTERING SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SURFACE-AREA; DECOMPOSITION; MG(OH)2 AB Equilibrium chemisorption of H2O at 613 Pa on nanometric and micrometric MgO particles was measured at 549-1053 K. Degrees of coverage are calculated on the assumptions that only {100} surfaces of MgO were exposed and that each surface O2- ion reacted with H20 to form 2OH- ions. When the thermal entropy of adsorption is assumed to be equal to the correspondent value for the reaction of H2O(v) with MgO to form Mg(OH)2, the data fit a regular solution model. The enthalpy of adsorption is calculated to be -189 kJ mol-1 at low coverage and -113 kJ mol-1 at 70% coverage. At temperature of 898 K and above water dissolved rapidly enough in the nanometric MgO particles to permit the equilibrium concentration to be measured. From the temperature dependence of solubility, the heat of solution is calculated to be -84 kJ mol-1. It is shown that if the water dissolved by reacting with O2- ions to form OH- which occupy O2- ion sites, the observed catalysis of MgO sintering by water vapor can be qualitatively explained. C1 LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV GENOA,FAC ENGN,INST CHEM,I-16126 GENOA,ITALY. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP BERUTO, D (reprint author), UNIV GENOA,FAC ENGN,INTERDEPT CTR MAT ENGN,I-16126 GENOA,ITALY. NR 22 TC 16 Z9 16 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 SEP 9 PY 1993 VL 97 IS 36 BP 9201 EP 9205 DI 10.1021/j100138a022 PG 5 WC Chemistry, Physical SC Chemistry GA LX923 UT WOS:A1993LX92300022 ER PT J AU MULLINS, DR LYMAN, PF AF MULLINS, DR LYMAN, PF TI ADSORPTION AND REACTION OF METHANETHIOL ON W(001) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SURFACE PHOTOEMISSION; DECOMPOSITION; SULFUR; CO; THIOPHENE; TUNGSTEN; NI(110); NI(100); PT(111); CARBON AB Methanethiol (CH3SH) adsorbs dissociatively on W(001) at 100 K, forming two distinct intermediates. These species have been identified by S 2p soft X-ray photoelectron spectroscopy (SXPS) as methyl thiolate moieties adsorbed in different bonding sites. Both species are stable at all coverages up to 150 K. At low coverages the thiolates totally decompose upon heating into atomic C and S and gaseous H-2. At high coverages a competing pathway produces atomic S and gaseous CH4. The thiolate adsorbed in a fourfold hollow site undergoes C-S bond scission at a lower temperature than the species in a lower coordination site. At high coverage the fourfold bonded intermediate preferentially leads to total decomposition whereas the other species favors methane formation. RP MULLINS, DR (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 40 TC 37 Z9 37 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 SEP 9 PY 1993 VL 97 IS 36 BP 9226 EP 9232 DI 10.1021/j100138a026 PG 7 WC Chemistry, Physical SC Chemistry GA LX923 UT WOS:A1993LX92300026 ER PT J AU MILLER, J KREBS, GF PANETTA, J SCHROEDER, LS KIRK, PN WANG, ZF BAUER, W BENENSON, W CEBRA, D CRONQVIST, M LI, BA PFAFF, R REPOSEUR, T STEVENSON, J VANDERMOLEN, A WESTFALL, G WINFIELD, JS YOUNG, B MURAKAMI, T SUZUKI, T TANIHATA, I AF MILLER, J KREBS, GF PANETTA, J SCHROEDER, LS KIRK, PN WANG, ZF BAUER, W BENENSON, W CEBRA, D CRONQVIST, M LI, BA PFAFF, R REPOSEUR, T STEVENSON, J VANDERMOLEN, A WESTFALL, G WINFIELD, JS YOUNG, B MURAKAMI, T SUZUKI, T TANIHATA, I TI MASS DEPENDENCE OF PION-PRODUCTION IN HEAVY-ION COLLISIONS NEAR, BUT BELOW THRESHOLD SO PHYSICS LETTERS B LA English DT Article ID RELATIVISTIC ENERGIES; LIGHT FRAGMENTS; NEGATIVE PIONS; SPECTRA; MODEL; NUCLEON; PROTONS AB We have measured the inclusive cross section for production of negative pions near mid-rapidity in Ne-20 + NaF, La-139 + La-139 and Au-197 + Au-197 collisions at E = 183 and 236 MeV/u. Au + Au is the heaviest system from which subthreshold pion production has been measured to date. The dependence of the pion cross section on pion energy, beam energy and associated charged particle multiplicity is consistent with previous results both above and below threshold. The dependence of the cross section on the mass of the colliding system varies only slightly as the beam energy is reduced below threshold, in contrast to some previous measurements. Comparison with theory suggests that at these energies the pion production process is still dominated by nucleon-nucleon collisions. C1 LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. MICHIGAN STATE UNIV,NATL SUPERCONDUCTING CYCLOTRON LAB,E LANSING,MI 48824. TOKYO INST TECHNOL,DEPT PHYS,MEGURO KU,TOKYO 152,JAPAN. INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. RP MILLER, J (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 24 TC 1 Z9 1 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 SEP 9 PY 1993 VL 314 IS 1 BP 7 EP 12 DI 10.1016/0370-2693(93)91314-D PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LW395 UT WOS:A1993LW39500002 ER PT J AU JAIN, V PAPADOPOULOS, A AF JAIN, V PAPADOPOULOS, A TI 1ST-ORDER PHASE-TRANSITION IN A 2 HIGGS-DOUBLET MODEL WITH M(H)GREATER-THAN-M(W) SO PHYSICS LETTERS B LA English DT Article ID BARYON ASYMMETRY; GAUGE-THEORIES; FINITE TEMPERATURE; ELECTROWEAK THEORY; SYMMETRY BEHAVIOR; STANDARD MODEL; BARYOGENESIS; UNIVERSE; SUPERCONDUCTORS; 1ST-ORDER AB We study the 3D effective field theory of a weakly coupled two Higgs-doublet scalar model at high temperature. Our model has three scalar quartic couplings and an O(4) symmetry which is spontaneously broken by a nonzero scalar field vev at zero temperature. Using high temperature perturbation theory, renormalization group arguments in 4-epsilon dimensions, as well as 1/N expansion techniques in 3 dimensions, we argue that the transition from the high temperature symmetry restoring phase to the low temperature phase is first order for a range of scalar couplings. This result is not due to gauge couplings. We discuss the implications of our results for the transition in the two Higgs-doublet electroweak model, especially when the lightest neutral Higgs is heavier than the W-bosons. RP JAIN, V (reprint author), LAWRENCE BERKELEY LAB,THEORET PHYS RES LABS,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 46 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 9 PY 1993 VL 314 IS 1 BP 95 EP 103 DI 10.1016/0370-2693(93)91327-J PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LW395 UT WOS:A1993LW39500015 ER PT J AU BARNHART, DM CLARK, DL GORDON, JC HUFFMAN, JC WATKIN, JG ZWICK, BD AF BARNHART, DM CLARK, DL GORDON, JC HUFFMAN, JC WATKIN, JG ZWICK, BD TI TETRAMERIC LANTHANIDE NEOPENTOXIDE COMPLEXES WITH AGOSTIC LN...H-C INTERACTIONS - X-RAY CRYSTAL-STRUCTURES OF LN4(OCH2-T-BU)12 (LN = LA, ND) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID YTTRIUM; ALKOXIDES; DERIVATIVES; CHEMISTRY; SCANDIUM; CLUSTERS; OXYGEN; OXOALKOXIDE; PRECURSORS; ARYLOXIDES C1 LOS ALAMOS NATL LAB, INORGAN & STRUCT CHEM GRP, INC-1, MAIL STOP C346, LOS ALAMOS, NM 87545 USA. LOS ALAMOS NATL LAB, DIV NUCL MAT TECHNOL, LOS ALAMOS, NM 87545 USA. INDIANA UNIV, CTR MOLEC STRUCT, BLOOMINGTON, IN 47405 USA. RI Clark, David/A-9729-2011 NR 35 TC 64 Z9 64 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD SEP 8 PY 1993 VL 115 IS 18 BP 8461 EP 8462 DI 10.1021/ja00071a071 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA LX752 UT WOS:A1993LX75200071 ER PT J AU LONG, HW GAEDE, HC SHORE, J REVEN, L BOWERS, CR KRITZENBERGER, J PIETRASS, T PINES, A TANG, P REIMER, JA AF LONG, HW GAEDE, HC SHORE, J REVEN, L BOWERS, CR KRITZENBERGER, J PIETRASS, T PINES, A TANG, P REIMER, JA TI HIGH-FIELD CROSS-POLARIZATION NMR FROM LASER-POLARIZED XENON TO A POLYMER SURFACE SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID SOLIDS; SPINS; GAS C1 LAWRENCE BERKELEY LAB,DEPT CHEM,DIV MAT SCI,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,CTR ADV MAT,DEPT CHEM ENGN,BERKELEY,CA 94720. RI Reven, Linda/F-3679-2011; Gaede, Holly/B-7392-2015 OI Gaede, Holly/0000-0003-4444-4394 NR 16 TC 86 Z9 88 U1 1 U2 17 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 SEP 8 PY 1993 VL 115 IS 18 BP 8491 EP 8492 DI 10.1021/ja00071a086 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA LX752 UT WOS:A1993LX75200086 ER PT J AU LORIMER, GH CHEN, YR HARTMAN, FC AF LORIMER, GH CHEN, YR HARTMAN, FC TI A ROLE FOR THE EPSILON-AMINO GROUP OF LYSINE-334 OF RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE IN THE ADDITION OF CARBON-DIOXIDE TO THE 2,3-ENEDIOL(ATE) OF RIBULOSE 1,5-BISPHOSPHATE SO BIOCHEMISTRY LA English DT Article ID RIBULOSEBISPHOSPHATE CARBOXYLASE; ACTIVE-SITE; BISPHOSPHATE CARBOXYLASE; RHODOSPIRILLUM-RUBRUM; REACTION-INTERMEDIATE; OXYGENASE; RESOLUTION; RUBISCO; ANALOGS; SPINACH AB Earlier structural and functional studies of ribulose-1,5-bisphosphate carboxylase/oxygenase imply that K334 facilitates the addition of gaseous substrate to the 2,3-enediol(ate) derived from ribulose 1,5-bisphosphate. Crystallographic analysis of the activated spinach enzyme [Knight et al. (1990) J. Mol. Biol. 215, 113-160] shows that the lysyl side chain is appropriately positioned to stabilize the transition state for the addition of CO2 to the enediol(ate). Furthermore, despite total impairment of carboxylase and oxygenase activities, site-directed mutants of the Rhodospirillum rubrum enzyme with replacements for lysine K334 (formerly designated K329) retain the capacity to enolize ribulose bisphosphate, demonstrating that the primary catalytic lesion lies beyond this initial step [Soper et al. (1988) Protein Eng. 2, 39-44; Hartman & Lee (1989) J. Biol. Chem. 264, 11784-11789]. We now show that the K334C mutant is also competent in the latter stages of catalysis, whereby 2'-carboxy-3-keto-D-arabinitol 1,5-bisphosphate, the six-carbon intermediate of the carboxylation pathway, is correctly processed to 3-phosphoglycerate. Thus, the impairment of the mutant in overall catalysis can be attributed to preferential disruption of the reaction of CO2 or O2 with the enzyme-bound enediol(ate). Chemical rescue of the K334C mutant by aminoethylation and aminopropylation shows that this disruption reflects, at least in part, a failure to adequately stabilize the relevant transition state. With several simplifying assumptions, the CO2/O2 specificity factor tau can be reduced to the ratio of the fundamental second-order rate constants for the interaction of the gaseous substrates with the enzyme-bound 2,3-enediol(ate) of ribulose bisphosphate. The tau-value is therefore a measure of the differential stabilization of the transition states that lead to the carboxylated and oxygenated intermediates. Our observations of altered tau-values and hence differential perturbation of transition states, correlated with substitutions of K334 with S-(2-aminoethyl)cysteine and S-(3-aminopropyl)cysteine, lend strong credence to one assigned role for this lysyl residue. C1 OAK RIDGE NATL LAB,DIV BIOL,PROT ENGN PROGRAM,OAK RIDGE,TN 37831. RP LORIMER, GH (reprint author), DUPONT CO INC,DEPT CENT RES & DEV,EXPTL STN,WILMINGTON,DE 19880, USA. NR 43 TC 46 Z9 46 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 7 PY 1993 VL 32 IS 35 BP 9018 EP 9024 DI 10.1021/bi00086a006 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA LW440 UT WOS:A1993LW44000006 PM 8369274 ER PT J AU KEPLER, TB PERELSON, AS AF KEPLER, TB PERELSON, AS TI SOMATIC HYPERMUTATION IN B-CELLS - AN OPTIMAL-CONTROL TREATMENT SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID GERMINAL-CENTERS; IMMUNE-RESPONSE; ANTIBODY REPERTOIRE; INCREASE AFFINITY; ANTIGEN; MATURATION; MEMORY; GENERATION; SELECTION; MUTATION C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP KEPLER, TB (reprint author), SANTA FE INST,1660 OLD PECOS TRAIL,SANTA FE,NM 87501, USA. OI Kepler, Thomas/0000-0002-1383-6865 FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI28433] NR 37 TC 86 Z9 90 U1 0 U2 5 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 SEP 7 PY 1993 VL 164 IS 1 BP 37 EP 64 DI 10.1006/jtbi.1993.1139 PG 28 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA MB945 UT WOS:A1993MB94500003 PM 8264243 ER PT J AU HOHIMER, JP CRAFT, DC VAWTER, GA AF HOHIMER, JP CRAFT, DC VAWTER, GA TI EFFECT OF THE Y-JUNCTION OUTPUT COUPLER ON THE LASING THRESHOLD OF SEMICONDUCTOR RING LASERS SO APPLIED PHYSICS LETTERS LA English DT Article AB We report the first measurements of the effect of a Y-junction output coupler on the continuous-wave (cw) lasing threshold of rib-waveguide semiconductor ring lasers. We show that the Y-junction induced loss in this type of ring diode laser depends on the ring radius (r), and increases the lasing threshold current density substantially for devices with r < 200 mum. For our devices with radii of 50-100 mum, the Y-junction loss term is shown to be the dominant factor affecting the cw lasing threshold. We also report the first measurements of the dependence of the cw lasing threshold on the width (w) of the Y-junction output coupler, and show that the threshold current density increases linearly for 0 less-than-or-equal-to w less-than-or-equal-to 9 mum. RP SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. NR 15 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 6 PY 1993 VL 63 IS 10 BP 1325 EP 1327 DI 10.1063/1.109719 PG 3 WC Physics, Applied SC Physics GA LW183 UT WOS:A1993LW18300009 ER PT J AU FRIEDMANN, TA BERNARDEZ, LJ MCCARTY, KF KLAUS, EJ OTTESEN, DK JOHNSEN, HA CLIFT, WM AF FRIEDMANN, TA BERNARDEZ, LJ MCCARTY, KF KLAUS, EJ OTTESEN, DK JOHNSEN, HA CLIFT, WM TI DIAMOND DEPOSITION ON POLYCRYSTALLINE FILMS OF CUBIC BORON-NITRIDE SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; CRYSTALLOGRAPHIC ORIENTATIONS; RAMAN MICROPROBE; THIN-FILMS; GROWTH; FILAMENT; REACTOR AB We have grown diamond films on films of cubic boron nitride (cBN). The cBN films were grown on Si(100) substrates using ion-assisted pulsed laser deposition. Fourier transform infrared (FTIR) spectroscopy indicated that the BN films contained approximately 75% sp3-bonded cBN. The as-grown cBN films were inserted with no surface pretreatment (e.g., abrading or scratching) into a conventional hot filament diamond reactor. In situ Raman spectroscopy was used to confirm diamond synthesis during growth. The nucleation density of the diamond films was estimated at 1 X 10(9)/CM2, equivalent to or higher than the best values for scratched silicon substrates. In addition, we found that the cBN films were etched in the diamond reactor; a film thickness greater than or similar to 1500 angstrom was required to prevent total film loss before diamond nucleation occurred. The presence of cBN under the diamond was established using FTIR spectroscopy 'and Auger electron spectroscopy. RP FRIEDMANN, TA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 20 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 SEP 6 PY 1993 VL 63 IS 10 BP 1342 EP 1344 DI 10.1063/1.109725 PG 3 WC Physics, Applied SC Physics GA LW183 UT WOS:A1993LW18300015 ER PT J AU ZHANG, J KEYES, BM ASHER, SE AHRENKIEL, RK TIMMONS, ML AF ZHANG, J KEYES, BM ASHER, SE AHRENKIEL, RK TIMMONS, ML TI GIANT RECOMBINATION CENTERS IN AL0.10GA0.90AS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION SO APPLIED PHYSICS LETTERS LA English DT Article ID MINORITY-CARRIER LIFETIME; ALXGA1-XAS AB The hole lifetime in n-type Al0.10Ga0.90As is controlled by recombination centers with capture cross sections of about 10(-12) CM2. Correlated time-resolved photoluminescence and deep level transient spectroscopy measurements link these centers to well-known impurity oxygen complexes. Film growth at temperatures above about 720-degrees-C eliminate these oxygen complexes from the epitaxial layer resulting in greatly improved electronic properties. C1 RES TRIANGLE INST,RES TRIANGLE PK,NC 27709. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 14 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 6 PY 1993 VL 63 IS 10 BP 1369 EP 1371 DI 10.1063/1.109679 PG 3 WC Physics, Applied SC Physics GA LW183 UT WOS:A1993LW18300024 ER PT J AU ZHANG, SB ZUNGER, A AF ZHANG, SB ZUNGER, A TI PREDICTION OF UNUSUAL ELECTRONIC-PROPERTIES OF SI QUANTUM FILMS SO APPLIED PHYSICS LETTERS LA English DT Article AB Direct pseudopotential band structure calculations of thin Si(001) films reveal a number of features that are unexpected on the basis of conventional quantum confinement models: (i) The energies of some valence-band states exhibit oscillations when the number of monolayers in the film changes from even to odd, (ii) certain film wave functions have a cosine (rather than sine) envelope function, and (iii) the energy of the highest occupied film state remains pinned at a constant value for all even-layered film. We demonstrate a simple alternative to the effective-mass model which explains these results. RP ZHANG, SB (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 4 TC 38 Z9 39 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 SEP 6 PY 1993 VL 63 IS 10 BP 1399 EP 1401 DI 10.1063/1.109689 PG 3 WC Physics, Applied SC Physics GA LW183 UT WOS:A1993LW18300034 ER PT J AU NORTON, DP LOWNDES, DH AF NORTON, DP LOWNDES, DH TI ENHANCED SUPERCONDUCTING PROPERTIES IN ULTRATHIN YBA2CU3O7-DELTA LAYERS SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING TUNNELING MICROSCOPY; YBA2CU3O7-X/PRBA2CU3O7-X SUPERLATTICES; YBA2CU3O7/PRBA2CU3O7 SUPERLATTICES; GROWTH-MECHANISM; THIN-FILMS; MICROSTRUCTURE; MGO AB The superconducting properties of ultrathin c-axis-oriented YBa2CU3O7-delta(YBCO) layers can be significantly enhanced by use of more conductive buffer and cap layers. In particular, Pr0.5Ca0.5Ba2CU3O7-delta/YBCO/Pr0.5Ca0.5Ba5CU3O7-delta trilayer structures, with YBCO layer thickness as small as 1 unit cell, have superior transport properties to PrBa2CU3O7-delta/YBCO/PrBa2Cu3O7-delta structures, including an increase in T(c) and a narrower superconducting transition. The enhanced superconducting properties that result from using Ca-(hole) doped buffer and cap layers may be a result of a diminished perturbation of the order parameter at growth-related steps in the electrical continuity of the YBCO layer. RP NORTON, DP (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 28 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 6 PY 1993 VL 63 IS 10 BP 1432 EP 1434 DI 10.1063/1.109648 PG 3 WC Physics, Applied SC Physics GA LW183 UT WOS:A1993LW18300045 ER PT J AU GOCKELER, M KRONFELD, AS SCHIERHOLZ, G WIESE, UJ AF GOCKELER, M KRONFELD, AS SCHIERHOLZ, G WIESE, UJ TI CONTINUUM GAUGE-FIELDS FROM LATTICE GAUGE-FIELDS SO NUCLEAR PHYSICS B LA English DT Article ID TOPOLOGICAL SUSCEPTIBILITY; ANOMALIES; FERMIONS; PROOF; NEUTRINOS; ABSENCE; THEOREM AB On the lattice some of the salient features of pure gauge theories and of gauge theories with fermions in complex representations of the gauge group seem to be lost. These features can be recovered by considering part of the theory in the continuum. The prerequisite for that is the construction of continuum gauge fields from lattice gauge fields. Such a construction, which is gauge covariant and complies with geometrical constructions of the topological charge on the lattice, is given in this paper. The procedure is explicitly carried out in the U(1) theory in two dimensions, where it leads to simple results. C1 UNIV BERN, INST THEORET PHYS, CH-3012 BERN, SWITZERLAND. DESY, W-2000 HAMBURG 52, GERMANY. FERMILAB NATL ACCELERATOR LAB, THEORET PHYS GRP, BATAVIA, IL 60510 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM JULICH, HLRZ, THEOR ELEMENTARTEILCHEN GRP, W-5170 JULICH 1, GERMANY. RP RHEIN WESTFAL TH AACHEN, INST THEORET PHYS, SOMMERFELDSTR, W-5100 AACHEN, GERMANY. NR 31 TC 36 Z9 36 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD SEP 6 PY 1993 VL 404 IS 3 BP 839 EP 852 DI 10.1016/0550-3213(93)90599-K PG 14 WC Physics, Particles & Fields SC Physics GA LV531 UT WOS:A1993LV53100010 ER PT J AU ALEXOPOULOS, T ALLEN, C ANDERSON, EW BALAMURALI, V BANERJEE, S BEERY, PD BHAT, P BISHOP, JM BISWAS, NN BUJAK, A CARMONY, DD CARTER, T CHOI, Y COLE, P DEBONTE, R DECARLO, V ERWIN, AR FINDEISEN, C GOSHAW, AT GUTAY, LJ HIRSCH, AS HOJVAT, C JENNINGS, JR KENNEY, VP LINDSEY, CS LOOMIS, C LOSECCO, JM MCMAHON, T MCMANUS, AP MORGAN, N NELSON, K OH, SH PORILE, NT REEVES, D RIMAI, A ROBERTSON, WJ SCHARENBERG, RP STAMPKE, SR STRINGFELLOW, BC THOMPSON, M TURKOT, F WALKER, WD WANG, CH WARCHOL, J WESSON, DK ZHAN, Y AF ALEXOPOULOS, T ALLEN, C ANDERSON, EW BALAMURALI, V BANERJEE, S BEERY, PD BHAT, P BISHOP, JM BISWAS, NN BUJAK, A CARMONY, DD CARTER, T CHOI, Y COLE, P DEBONTE, R DECARLO, V ERWIN, AR FINDEISEN, C GOSHAW, AT GUTAY, LJ HIRSCH, AS HOJVAT, C JENNINGS, JR KENNEY, VP LINDSEY, CS LOOMIS, C LOSECCO, JM MCMAHON, T MCMANUS, AP MORGAN, N NELSON, K OH, SH PORILE, NT REEVES, D RIMAI, A ROBERTSON, WJ SCHARENBERG, RP STAMPKE, SR STRINGFELLOW, BC THOMPSON, M TURKOT, F WALKER, WD WANG, CH WARCHOL, J WESSON, DK ZHAN, Y TI INCLUSIVE PHOTON PRODUCTION FROM P(P)OVER-BAR COLLISIONS AT ROOT-S = 1.8 TEV SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUARK-GLUON PLASMA; PI+P INTERACTIONS; DRIFT CHAMBER; 200 GEV/U; PERFORMANCE; COLLIDER; DESIGN; K+P AB We report a measurement of the inclusive production of low-energy photons from ppBAR collisions at square-root s = 1.8 TeV. A NaI calorimeter located near eta = 0 was used to measure the photon transverse momentum spectrum over the range 30 less-than-or-equal-to p(t) less-than-or-equal-to 5000 MeV/c. The data are compared to the photon production expected from known particle decays in an attempt to isolate a low-energy direct photon signal. We find no evidence for excess photons above those expected from hadron decays and place an upper limit of 16% (90% C.L.) on any excess direct photons in the p(t) range from 30 to 100 MeV/c. C1 DEPAUW UNIV,DEPT PHYS,GREENCASTLE,IN 46135. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. DUKE UNIV,DEPT PHYS,DURHAM,NC 27708. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907. RP ALEXOPOULOS, T (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. NR 25 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1490 EP 1493 DI 10.1103/PhysRevLett.71.1490 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100004 ER PT J AU HAN, T PARKE, S AF HAN, T PARKE, S TI HEAVY TOP-QUARK SEARCHES IN THE DILEPTON MODE AT THE FERMILAB TEVATRON SO PHYSICAL REVIEW LETTERS LA English DT Article ID HADRON COLLIDERS; JETS; ASSOCIATION AB We present the results of a detailed study of the effects of b tagging on the heavy top-quark signal and backgrounds for the modes of the dilepton plus two high-transverse-energy jets at the Fermilab Tevatron. The general characteristics of the heavy top-quark signal events are also discussed so that a comparison can be made between b tagging and imposing stringent kinematical cuts to eliminate backgrounds. RP HAN, T (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1494 EP 1497 DI 10.1103/PhysRevLett.71.1494 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100005 ER PT J AU HAO, J KUO, TTS REUBER, A HOLINDE, K SPETH, J MILLENER, DJ AF HAO, J KUO, TTS REUBER, A HOLINDE, K SPETH, J MILLENER, DJ TI HYPERNUCLEUS NU-O-16 AND ACCURATE HYPERON-NUCLEON G-MATRIX INTERACTIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID EXCHANGE-POTENTIAL APPROACH; BARYON-BARYON SCATTERING; MODEL AB We have performed accurate G-matrix calculations for the hypernucleus O-16LAMBDA using the one- and two-boson-exchange Julich hyperon-nucleon potentials. A finite-nuclei Pauli operator defined in terms of oscillator wave functions is employed, and treated essentially exactly in solving the coupled LAMBDAN and SIGMAN G-matrix equation. Numerical stability concerning the choice of the k-space mesh points for discretization and the accuracy of a finite-boundary approximation are examined. Our calculated spectrum for O-16LAMBDA is in good agreement with experiments. C1 FORSCHUNGSZENTRUM JULICH GMBH, INST KERNPHYS THEORIE, D-52425 JULICH, GERMANY. BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. UNIV WASHINGTON, INST NUCL THEORY, SEATTLE, WA 98195 USA. RP HAO, J (reprint author), SUNY, DEPT PHYS, STONY BROOK, NY 11794 USA. NR 19 TC 39 Z9 40 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1498 EP 1501 DI 10.1103/PhysRevLett.71.1498 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100006 ER PT J AU TSANG, MB HSI, WC LYNCH, WG BOWMAN, DR GELBKE, CK LISA, MA PEASLEE, GF KUNDE, GJ BEGEMANNBLAICH, ML HOFMANN, T HUBELE, J KEMPTER, J KREUTZ, P KUNZE, WD LINDENSTRUTH, V LYNEN, U MANG, M MULLER, WFJ NEUMANN, M OCKER, B OGILVIE, CA POCHODZALLA, J ROSENBERGER, F SANN, H SCHUTTAUF, A SERFLING, V STROTH, J TRAUTMANN, W TUCHOLSKI, A WORNER, A ZUDE, E ZWIEGLINSKI, B AIELLO, S IMME, G PAPPALARDO, V RACITI, G CHARITY, RJ SOBOTKA, LG IORI, I MORONI, A SCARDONI, R FERRERO, A SEIDEL, W BLAICH, T STUTTGE, L COSMO, A FRIEDMAN, WA PEILERT, G AF TSANG, MB HSI, WC LYNCH, WG BOWMAN, DR GELBKE, CK LISA, MA PEASLEE, GF KUNDE, GJ BEGEMANNBLAICH, ML HOFMANN, T HUBELE, J KEMPTER, J KREUTZ, P KUNZE, WD LINDENSTRUTH, V LYNEN, U MANG, M MULLER, WFJ NEUMANN, M OCKER, B OGILVIE, CA POCHODZALLA, J ROSENBERGER, F SANN, H SCHUTTAUF, A SERFLING, V STROTH, J TRAUTMANN, W TUCHOLSKI, A WORNER, A ZUDE, E ZWIEGLINSKI, B AIELLO, S IMME, G PAPPALARDO, V RACITI, G CHARITY, RJ SOBOTKA, LG IORI, I MORONI, A SCARDONI, R FERRERO, A SEIDEL, W BLAICH, T STUTTGE, L COSMO, A FRIEDMAN, WA PEILERT, G TI ONSET OF NUCLEAR VAPORIZATION IN AU-197+AU-197 COLLISIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID E/A = 50; MULTIFRAGMENT EMISSION; FRAGMENT FLOW; DYNAMICS; SYSTEM; AR-36+AU-197; SIMULATION; MODEL; STATE; AU AB Multifragmentation has been measured for Au-197 + Au-197 collisions at E/A = 100, 250, and 400 MeV. The mean fragment multiplicity increases monotonically with the charged particle multiplicity at E/A = 100 MeV, but decreases for central collisions with incident energy, consistent with the onset of nuclear vaporization. Molecular dynamics calculations follow some trends but underpredict the observed fragment multiplicities. Including the statistical decay of excited residues improves the agreement for peripheral collisions but worsens it for central collisions. C1 MICHIGAN STATE UNIV, NATL SUPERCONDUCTING CYCLOTRON LAB, E LANSING, MI 48824 USA. GESELL SCHWERIONENFORSCH MBH, W-6100 DARMSTADT, GERMANY. UNIV CATANIA, DIPARTIMENTO FIS, I-95127 CATANIA, ITALY. IST NAZL FIS NUCL, CATANIA, ITALY. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130 USA. UNIV MILAN, IST SCI FIS, I-20133 MILAN, ITALY. FORSCHUNGSZENTRUM ROSSENDORF, DRESDEN, GERMANY. UNIV MAINZ, INST KERNCHEM, W-6500 MAINZ, GERMANY. CTR RECH NUCL, F-67037 STRASBOURG, FRANCE. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RP MICHIGAN STATE UNIV, DEPT PHYS & ASTRON, E LANSING, MI 48824 USA. RI Lynch, William/I-1447-2013 OI Lynch, William/0000-0003-4503-176X NR 29 TC 146 Z9 150 U1 1 U2 8 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 SEP 6 PY 1993 VL 71 IS 10 BP 1502 EP 1505 DI 10.1103/PhysRevLett.71.1502 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100007 ER PT J AU BELKACEM, A GOULD, H FEINBERG, B BOSSINGHAM, R MEYERHOF, WE AF BELKACEM, A GOULD, H FEINBERG, B BOSSINGHAM, R MEYERHOF, WE TI MEASUREMENT OF ELECTRON-CAPTURE FROM ELECTRON-POSITRON PAIR PRODUCTION IN RELATIVISTIC HEAVY-ION COLLISIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID ATOMIC-COLLISIONS; ELECTROMAGNETIC PROCESSES; ENERGIES AB We have used a novel new spectrometer to make the first observation and measurement of electron capture from e+-e- pair production in relativistic heavy ion collisions. For a 0.96 GeV/nucleon U92+ beam the cross section for a Au target is 2.19(0.25) b, and the target Z dependence is Z(t)2.8+/-0.25. We also measured the energy and angular distributions of the positrons, and for comparison, the cross section for e+-e- pair production without capture is 3.30(0.65) b. C1 LAWRENCE BERKELEY LAB, DIV ACCELERATOR & FUS RES, BERKELEY, CA 94720 USA. LAWRENCE BERKELEY LAB, DIV NUCL SCI, BERKELEY, CA 94720 USA. STANFORD UNIV, DEPT PHYS, STANFORD, CA 94305 USA. RP BELKACEM, A (reprint author), LAWRENCE BERKELEY LAB, DIV CHEM SCI, BLDG 71-259, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 22 TC 53 Z9 53 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1514 EP 1517 DI 10.1103/PhysRevLett.71.1514 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100010 ER PT J AU LOWRY, CW DECOLSTOUN, FB PAUL, AE KHITROVA, G GIBBS, HM GRANTHAM, JW JIN, R BOGGAVARAPU, D KOCH, SW SARGENT, M BRENNAN, TM HAMMONS, BE AF LOWRY, CW DECOLSTOUN, FB PAUL, AE KHITROVA, G GIBBS, HM GRANTHAM, JW JIN, R BOGGAVARAPU, D KOCH, SW SARGENT, M BRENNAN, TM HAMMONS, BE TI ACCELERATION OF COHERENT TRANSFER OF ENERGY BY STIMULATED-EMISSION AND ABSORPTION SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEMICONDUCTOR-LASERS; SODIUM VAPOR; OSCILLATION AB Coherent transfer of energy (CTE) gives rise to a new peak and dip in the probe gain spectrum that move proportionally with the intracavity injected power showing that stimulated emission and absorption significantly speed up the semiconductor response. Gain modification is seen in two nondegenerate, cross-polarized modes of a microcavity laser when light is injected into only one mode, giving strong evidence for the CTE origin of the gain asymmetry. C1 UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. SANDIA NATL LABS,DEPT 1311,ALBUQUERQUE,NM 87185. RP LOWRY, CW (reprint author), UNIV ARIZONA,CTR OPT SCI,TUCSON,AZ 85721, USA. NR 20 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1534 EP 1537 DI 10.1103/PhysRevLett.71.1534 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100015 ER PT J AU TIDSWELL, IM MARKOVIC, NM ROSS, PN AF TIDSWELL, IM MARKOVIC, NM ROSS, PN TI POTENTIAL-DEPENDENT SURFACE RELAXATION OF THE PT(001) ELECTROLYTE INTERFACE SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-CRYSTAL SURFACES; X-RAY-REFLECTIVITY; HYDROGEN; DIFFRACTION; ADSORPTION; RECONSTRUCTION; ELECTROSORPTION; AU(111); ANIONS AB X-ray reflectivity measurements were used to determine the structure of the Pt(001)/solution interface as a function of the applied potential in alkaline and acid electrolytes. Unlike the Pt(001)/vacuum interface, the electrolyte interface was found to be unreconstructed at all potentials. The lattice spacing between the first and second layer was found to be a function of potential in the region where approximately a monolayer of H was adsorbed. The expansion was up to 2.5% of a lattice spacing (0.05 angstrom) in alkaline electrolyte, and up to 1% of a lattice spacing in acid electrolytes. C1 UNIV BELGRADE,ICTM,INST ELECTROCHEM,BELGRADE,YUGOSLAVIA. RP TIDSWELL, IM (reprint author), LAWRENCE BERKELEY LAB,DIV MAT SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 19 TC 91 Z9 91 U1 3 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 SEP 6 PY 1993 VL 71 IS 10 BP 1601 EP 1604 DI 10.1103/PhysRevLett.71.1601 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100032 ER PT J AU SINGH, PP GONIS, A TURCHI, PEA AF SINGH, PP GONIS, A TURCHI, PEA TI TOWARD A UNIFIED APPROACH TO THE STUDY OF METALLIC ALLOYS - APPLICATION TO THE PHASE-STABILITY OF NI-PT SO PHYSICAL REVIEW LETTERS LA English DT Article ID COHERENT-POTENTIAL-APPROXIMATION; ATOMIC-SPHERE APPROXIMATION; ELECTRONIC-STRUCTURE; COMPOSITIONAL ORDER; 1ST-PRINCIPLES; ORIGINS; DENSITY AB We present the first implementation of a unified approach to the study of alloys, using the atomic-sphere approximation formulation of the Korringa-Kohn-Rostoker coherent potential approximation method [P. P. Singh and A. Gonis, Phys. Rev. B 48, 1989 (1993)], which allows the treatment of the disordered alloy and of the ordered alloys on an equal footing. We apply this method to the study of the phase stability of the Ni-Pt alloy and resolve a number of discrepancies that have arisen in recent studies of this system. RP SINGH, PP (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,L-268,LIVERMORE,CA 94550, USA. NR 28 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 6 PY 1993 VL 71 IS 10 BP 1605 EP 1608 DI 10.1103/PhysRevLett.71.1605 PG 4 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100033 ER PT J AU COHN, JL KRESIN, VZ REEVES, ME WOLF, SA AF COHN, JL KRESIN, VZ REEVES, ME WOLF, SA TI SUPERCONDUCTING-STATE THERMAL TRANSPORT IN YBA2CU3O7-DELTA SO PHYSICAL REVIEW LETTERS LA English DT Note ID HIGH-TC SUPERCONDUCTORS; UNTWINNED YBA2CU3O7-DELTA; CONDUCTIVITY C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. USN,RES LAB,MAT PHYS BRANCH,WASHINGTON,DC 20375. CATHOLIC UNIV AMER,DEPT PHYS,WASHINGTON,DC 20064. RP COHN, JL (reprint author), UNIV MIAMI,DEPT PHYS,CORAL GABLES,FL 33124, USA. RI Wolf, Stuart/A-7513-2009 NR 11 TC 26 Z9 26 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 SEP 6 PY 1993 VL 71 IS 10 BP 1657 EP 1657 DI 10.1103/PhysRevLett.71.1657 PG 1 WC Physics, Multidisciplinary SC Physics GA LW231 UT WOS:A1993LW23100046 ER PT J AU BRANDES, HK LARIMER, FW GECK, MK STRINGER, CD SCHURMANN, P HARTMAN, FC AF BRANDES, HK LARIMER, FW GECK, MK STRINGER, CD SCHURMANN, P HARTMAN, FC TI DIRECT IDENTIFICATION OF THE PRIMARY NUCLEOPHILE OF THIOREDOXIN-F SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Note ID ESCHERICHIA-COLI; CHLOROPLAST FRUCTOSE-1,6-BISPHOSPHATASE; SPINACH-CHLOROPLASTS; REDUCED FORM; PURIFICATION; MUTAGENESIS; ENZYME; ACTIVATION AB Thioredoxin, by virtue of the proximal active-site sulfhydryls (Trp-Cys-Gly-Pro-Cys), catalyzes thiol-disulfide exchange with specific target enzymes. Considerable data (chemical modification, spectroscopic, and crystallographic) have implicated the cysteinyl residue nearest the N terminus of thioredoxin as the primary nucleophile; however, direct proof has been lacking. Proof is now provided by characterization of site-directed mutants of thioredoxin f with respect to activation of chloroplastic fructose-1,6-bisphosphatase (FBPase). The C49S mutant retains the capacity to activate FBPase, whereas the C46S mutant is totally lacking in this regard. Based on kinetics of FBPase activation, wild-type and C49S thioredoxins exhibit half-saturation values of 0.9 and 4 muM, respectively. Lack of activation by C46S is not because of failure to interact with FBPase, for it exhibits a K(i) of 5 muM in competition with wild-type thioredoxin. Therefore, in the normal thioredoxin-catalyzed reduction pathway, Cys-46 is the nucleophile required to attack the disulfide of the substrate and Cys-49 serves to cleave the mixed disulfide intermediate, thus allowing for the release of oxidized thioredoxin and the reduced target enzyme. C1 UNIV NEUCHATEL,BIOCHIM VEGETALE LAB,CH-2000 NEUCHATEL,SWITZERLAND. RP BRANDES, HK (reprint author), UNIV TENNESSEE,OAK RIDGE GRAD SCH BIOMED SCI,OAK RIDGE NATL LAB,DIV BIOL,PROT ENGN PROGRAM,OAK RIDGE,TN 37831, USA. NR 27 TC 50 Z9 50 U1 2 U2 3 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 SEP 5 PY 1993 VL 268 IS 25 BP 18411 EP 18414 PG 4 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA LV659 UT WOS:A1993LV65900004 PM 8395501 ER PT J AU SESHADRI, T UZMAN, JA OSHIMA, J CAMPISI, J AF SESHADRI, T UZMAN, JA OSHIMA, J CAMPISI, J TI IDENTIFICATION OF A TRANSCRIPT THAT IS DOWN-REGULATED IN SENESCENT HUMAN FIBROBLASTS - CLONING, SEQUENCE-ANALYSIS, AND REGULATION OF THE HUMAN L7 RIBOSOMAL-PROTEIN GENE SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID MESSENGER-RNA; REPLICATIVE SENESCENCE; GROWTH-FACTOR; CELLULAR SENESCENCE; RIBONUCLEIC-ACID; C-FOS; CELLS; EXPRESSION; DIFFERENTIATION; OVEREXPRESSION AB Normal eukaryotic cells divide only a limited number of times before proliferation ceases due to cellular senescence. We previously reported that a constitutively expressed, non-cell cycle-regulated transcript of unknown identity declines severalfold when human fibroblasts become senescent. We show here, from the sequence of cDNA and genomic clones, that this transcript encodes L7, a structural protein of the large ribosomal subunit. The human L7 protein shares > 90% amino acid identity with the mouse and rat L7 proteins but is shorter than either rodent protein due to fewer basic repetitive motifs at the amino terminus. The position of the first intron is conserved between the mouse and human genes. The L7 mRNA was abundant, stable (t1/2 > 10 h), and polyadenylated in presenescent and senescent human fibroblasts; however, steady state mRNA levels were 5-10-fold lower in senescent cells, whether derived from fetal lung or neonatal foreskin. Quiescent and senescent cells synthesized protein at similar rates, yet only senescent cultures showed a decline in L7 mRNA. The mRNAs encoding five other ribosomal proteins (L5, P1, S3, S6, and S10) behaved similarly. The results suggest that the senescence-associated decline in L7 and other ribosomal protein mRNAs is unrelated to growth state or protein synthetic rate per se and support the view that senescence and quiescence are dissimilar states. C1 LAWRENCE BERKELEY LAB,DEPT CELL & MOLEC BIOL,1 CYCLOTRON RD,BERKELEY,CA 94720. FU NIA NIH HHS [AG09909] NR 41 TC 66 Z9 69 U1 0 U2 0 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 SEP 5 PY 1993 VL 268 IS 25 BP 18474 EP 18480 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA LV659 UT WOS:A1993LV65900017 PM 8360149 ER PT J AU NEEB, M RUBENSSON, JE BIERMANN, M EBERHARDT, W RANDALL, KJ FELDHAUS, J KILCOYNE, ALD BRADSHAW, AM XU, Z JOHNSON, PD MA, Y AF NEEB, M RUBENSSON, JE BIERMANN, M EBERHARDT, W RANDALL, KJ FELDHAUS, J KILCOYNE, ALD BRADSHAW, AM XU, Z JOHNSON, PD MA, Y TI EFFECTS OF TIME EVOLUTION OF COHERENTLY EXCITED VIBRATIONS IN MOLECULAR CORE-HOLE DECAY SPECTRA OF O2 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DEEXCITATION ELECTRON-SPECTROSCOPY; HIGH-RESOLUTION; STATES AB Lifetime vibrational interference effects modulate the line shapes observed in high-resolution studies of the decay of ultra-short-lived core-hole excited states in molecules. We have analyzed the decay of the 1sigma(u)-1pi(g)3 core excited state in O2, where for the first time subsets of vibronic eigenfunctions could be selected. We demonstrate that this type of spectroscopy can be used to verify the predictions of quantum mechanical interference theory describing the time evolution of coherently excited vibrational states on the femtosecond time scale. C1 FRITZ HABER INST, W-1000 BERLIN 33, GERMANY. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. RP NEEB, M (reprint author), FORSCHUNGSZENTRUM JULICH, IFF, POSTFACH 1913, W-5170 JULICH 1, GERMANY. RI Feldhaus, Josef/C-1130-2014; Kilcoyne, David/I-1465-2013 NR 20 TC 36 Z9 36 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD SEP 3 PY 1993 VL 212 IS 1-2 BP 205 EP 210 DI 10.1016/0009-2614(93)87131-L PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LV629 UT WOS:A1993LV62900034 ER PT J AU GARY, SP ANDERSON, BJ DENTON, RE FUSELIER, SA MCKEAN, ME WINSKE, D AF GARY, SP ANDERSON, BJ DENTON, RE FUSELIER, SA MCKEAN, ME WINSKE, D TI ION ANISOTROPIES IN THE MAGNETOSHEATH SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA DEPLETION LAYER; MIRROR WAVES; INSTABILITY; PRESSURE; SHOCKS AB One- and two-dimensional initial value hybrid computer simulations are used with a magnetosheath parameter model to study the consequences of the growth of the mirror and ion cyclotron anisotropy instabilities. Magnetosheath observations have demonstrated inverse correlations between the proton and helium ion temperature anisotropies and the proton parallel beta. Using the maximum growth rate as a fitting parameter, linear Vlasov instability theory for the proton cyclotron and helium cyclotron anisotropy instabilities reproduces both observed correlations. Furthermore, results from the asymptotic states of simulations of the ion cyclotron instabilities qualitatively reproduce both observations. C1 JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. DARTMOUTH COLL,HANOVER,NH 03755. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. RP GARY, SP (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Anderson, Brian/I-8615-2012 NR 18 TC 32 Z9 32 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD SEP 3 PY 1993 VL 20 IS 17 BP 1767 EP 1770 DI 10.1029/93GL01700 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LW834 UT WOS:A1993LW83400007 ER PT J AU MURNANE, JP SCHWARTZ, JL AF MURNANE, JP SCHWARTZ, JL TI CELL CHECKPOINT AND RADIOSENSITIVITY SO NATURE LA English DT Letter ID ATAXIA-TELANGIECTASIA CELLS; IRRADIATED HELA-CELLS; CYCLE CHECKPOINT; DNA-SYNTHESIS; P53; CAFFEINE; CANCER; REPLICATION; FIBROBLASTS; INDIVIDUALS C1 ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,ARGONNE,IL 60439. RP MURNANE, JP (reprint author), UNIV CALIF SAN FRANCISCO,RADIOBIOL & ENVIRONM HLTH LAB,SAN FRANCISCO,CA 94143, USA. NR 20 TC 29 Z9 30 U1 0 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 2 PY 1993 VL 365 IS 6441 BP 22 EP 22 DI 10.1038/365022a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LV646 UT WOS:A1993LV64600037 PM 8361532 ER PT J AU BASDEVANT, JL BERGER, EL DICUS, D KAO, C WILLENBROCK, S AF BASDEVANT, JL BERGER, EL DICUS, D KAO, C WILLENBROCK, S TI FINAL-STATE INTERACTION OF LONGITUDINAL VECTOR BOSONS SO PHYSICS LETTERS B LA English DT Article ID ULTRA HEAVY FERMIONS; HIGGS BOSONS; WEAK INTERACTIONS; MASS GENERATION; HIGH-ENERGIES; UNITARITY; ANNIHILATION; COLLISIONS; SCATTERING; COLLIDERS AB In the standard Higgs model of electroweak symmetry breaking, the Higgs boson is associated with both vector-boson and fermion mass generation. In contrast, we discuss a two-Higgs-doublet model in which these masses are associated with two different scalar bosons. We show that the Higgs boson associated with vector-boson mass generation produces a characteristic peak-dip structure in the cross section for ttBAR-->ZZ via a final-state interaction. C1 UNIV PARIS 06, LPTPE, F-75230 PARIS 05, FRANCE. ARGONNE NATL LAB, DIV HIGH ENERGY PHYS, ARGONNE, IL 60439 USA. UNIV TEXAS, CTR PARTICLE PHYS, AUSTIN, TX 78712 USA. FLORIDA STATE UNIV, DEPT PHYS, TALLAHASSEE, FL 32306 USA. FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. RP BASDEVANT, JL (reprint author), UNIV PARIS 11, UNIV PARIS 06, INST PHYS NUCL, DIV PHYS THEOR, UNITE RECH, F-91406 ORSAY, FRANCE. NR 42 TC 23 Z9 23 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 SEP 2 PY 1993 VL 313 IS 3-4 BP 402 EP 410 DI 10.1016/0370-2693(93)90010-F PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LV804 UT WOS:A1993LV80400010 ER PT J AU SHIRTS, RB AF SHIRTS, RB TI THE COMPUTATION OF EIGENVALUES AND SOLUTIONS OF MATHIEU DIFFERENTIAL-EQUATION FOR NONINTEGER ORDER SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE ALGORITHMS; EIGENVALUES; FLOQUET SOLUTIONS; MATHIEU EQUATION; NONINTEGER ORDER; NUMERICAL SOFTWARE; ORDINARY DIFFERENTIAL EQUATIONS ID SEMICLASSICAL THEORY; QUANTIZATION; MOLECULES AB Two algorithms for calculating the eigenvalues and solutions of Mathieu's differential equation for noninteger order are described. In the first algorithm, Leeb's method is generalized, expanding the Mathieu equation in Fourier series and diagonalizing the symmetric tridiagonal matrix that results. Numerical testing was used to parameterize the minimum matrix dimension that must be used to achieve accuracy in the eigenvalue of one part in 10(12). This method returns a set of eigenvalues below a given order and their associated solutions simultaneously. A second algorithm is presented which uses approximations to the eigenvalues (Taylor series and asymptotic expansions) and then iteratively corrects the approximations using Newton's method until the corrections are less than a given tolerance. A backward recursion of the continued fraction expansion is used. The second algorithm is faster and is optimized to obtain accuracy of one part in 10(14), but has only been implemented for orders less than 10.5. C1 BRIGHAM YOUNG UNIV,DEPT CHEM,PROVO,UT 84602. RP SHIRTS, RB (reprint author), IDAHO NATL ENGN LAB,IDAHO FALLS,ID, USA. NR 40 TC 25 Z9 26 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD SEP PY 1993 VL 19 IS 3 BP 377 EP 390 DI 10.1145/155743.155796 PG 14 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA MA500 UT WOS:A1993MA50000006 ER PT J AU SHIRTS, RB AF SHIRTS, RB TI ALGORITHM 721 - MTIEU1 AND MTIEU2 - 2 SUBROUTINES TO COMPUTE EIGENVALUES AND SOLUTIONS TO MATHIEU DIFFERENTIAL-EQUATION FOR NONINTEGER AND INTEGER ORDER SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE ALGORITHMS; EIGENVALUES; FLOQUET SOLUTIONS; FORTRAN; MATHIEU EQUATION; NONINTEGER ORDER; NUMERICAL SOFTWARE; ORDINARY DIFFERENTIAL EQUATIONS AB Two FORTRAN routines are described which calculate eigenvalues and eifenfunctions of Mathieu's differential equation for noninteger as well as integer order. MTIEU1 uses standard matrix techniques with dimension parameterized to give accuracy in the eigenvalue of one part in 10(12). MTIEU2 used continued fraction techniques and is optimized to give accuracy in the eigenvalue of one part in 10(14). The limitations of the algorithms are also discussed and illustrated. C1 BRIGHAM YOUNG UNIV,DEPT CHEM,PROVO,UT 84602. RP SHIRTS, RB (reprint author), IDAHO NATL ENGN LAB,IDAHO FALLS,ID, USA. NR 7 TC 14 Z9 15 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD SEP PY 1993 VL 19 IS 3 BP 391 EP 406 DI 10.1145/155743.155847 PG 16 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA MA500 UT WOS:A1993MA50000007 ER PT J AU JEMIAN, PR ENDERBY, JE MERRIAM, A PRICE, DL SABOUNGI, ML AF JEMIAN, PR ENDERBY, JE MERRIAM, A PRICE, DL SABOUNGI, ML TI MODULATED ANOMALOUS X-RAY-SCATTERING SO ACTA CRYSTALLOGRAPHICA SECTION A LA English DT Article ID AQUEOUS-SOLUTIONS; DIFFRACTION; HYDRATION AB To determine the partial structure associated with a particular element in a multicomponent system, contrast variation is proposed based on the use of modulated anomalous X-ray scattering (MAXS). The photon energy of the X-ray beam incident on the sample is modulated over a range of energies below an absorption edge of the selected element. Because of anomalous dispersion, measurement of the scattered-intensity gradient with respect to the energy gives the required information. MAXS can be used in both small-angle and wide-angle diffraction and is applicable, in principle, to crystalline, amorphous and liquid materials. Energy modulation obtained by oscillating the Bragg angle of the monochromator by a small amount, followed by phase-sensitive detection, leads to a significant reduction of both systematic and statistical errors. Results of a simulation study of MAXS from an aqueous solution of NiCl2 under extreme conditions of dilution and scattering contrast are presented. C1 UNIV BRISTOL,HH WILLS PHYS LAB,BRISTOL BS8 1TL,AVON,ENGLAND. RP JEMIAN, PR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 20 TC 3 Z9 3 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7673 J9 ACTA CRYSTALLOGR A JI Acta Crystallogr. Sect. A PD SEP 1 PY 1993 VL 49 BP 743 EP 749 DI 10.1107/S0108767393002867 PN 5 PG 7 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA MB109 UT WOS:A1993MB10900010 ER PT J AU WANG, HY NAJAFABADI, R SROLOVITZ, DJ LESAR, R AF WANG, HY NAJAFABADI, R SROLOVITZ, DJ LESAR, R TI SEGREGATION TO AND STRUCTURE OF [001] TWIST GRAIN-BOUNDARIES IN CU-NI ALLOYS SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID EMBEDDED-ATOM METHOD; SURFACE SEGREGATION; TILT BOUNDARIES; FCC METALS; ENERGY; SIMULATION; MODEL AB The segregation, thermodynamic, and structural properties of [001] twist boundaries in Cu-Ni alloys have been examined within a wide range of misorientations and temperatures. Cu always segregates to the boundary. The concentration of the first layer adjacent to the boundary increases monotonically with misorientation and no obvious cusps are observed. All other thermodynamic properties vary smoothly with the misorientation, with the exception of the vibrational entropy of the boundaries without segregation. The unsegregated vibrational entropy shows a large peak at the misorientation corresponding to the SIGMA17 boundary and two minima around the SIGMA13 and SIGMA5 boundary orientations. The concentration distribution within the plane of the grain boundaries can be described by the same structural unit model established for [001] twist boundaries in pure materials. Regions of large tensile stress show greater segregation than do regions of compressive stress. Regions of large shear stress tend to show reduced segregation compared with regions of small shear stress. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. RP WANG, HY (reprint author), UNIV MICHIGAN, DEPT MAT SCI & ENGN, ANN ARBOR, MI 48109 USA. RI LeSar, Richard/G-1609-2012 NR 40 TC 13 Z9 13 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD SEP PY 1993 VL 41 IS 9 BP 2533 EP 2546 DI 10.1016/0956-7151(93)90123-A PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LR484 UT WOS:A1993LR48400002 ER PT J AU ADAMS, JB WOLFER, WG AF ADAMS, JB WOLFER, WG TI VOID FORMATION IN RAPIDLY-SOLIDIFIED METALS SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID VACANCY CLUSTERS; HELIUM; NICKEL; ENERGIES; STABILITY; OXYGEN; STEEL AB A dynamic nucleation code has been developed for predicting the evolution of vacancy clusters and nanometer-size voids in rapidly-quenched metals containing helium and oxygen impurities. Calculations have been carried out for typical quench rates and subsequent heat treatments of the powders during and after consolidation. These calculations show that high densities of submicroscopic voids can form in rapidly quenched metal powders, due to the quenched-in vacancy supersaturation and the entrapment of gases. The significance of these nanometer voids to the morphology or precipitates formed in rapidly-solidified steels is discussed. C1 SANDIA NATL LABS, LIVERMORE, CA 94550 USA. RP ADAMS, JB (reprint author), UNIV ILLINOIS, DEPT MAT SCI & ENGN, URBANA, IL 61801 USA. NR 15 TC 10 Z9 10 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD SEP PY 1993 VL 41 IS 9 BP 2625 EP 2632 DI 10.1016/0956-7151(93)90131-B PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LR484 UT WOS:A1993LR48400010 ER PT J AU LLANES, L ROLLETT, AD LAIRD, C BASSANI, JL AF LLANES, L ROLLETT, AD LAIRD, C BASSANI, JL TI EFFECT OF GRAIN-SIZE AND ANNEALING TEXTURE ON THE CYCLIC RESPONSE AND THE SUBSTRUCTURE EVOLUTION OF POLYCRYSTALLINE COPPER SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID STRESS-STRAIN RESPONSE; PERSISTENT SLIP BANDS; SINGLE-CRYSTALS; DISLOCATION-STRUCTURES; MECHANICAL PROPERTIES; AMPLITUDE; BEHAVIOR; FATIGUE; LOCALIZATION; MICROSTRUCTURES AB In attempting to interpret the mechanical response of polycrystalline copper, for which the results in the literature show marked scatter, the effects of microstructure on the cyclic behavior and the substructure evolution of copper polycrystals have been investigated. The microstructure is described by a complex factor-grain size and texture combined. It is found that there is a very significant effect of microstructure in the cyclic response of copper at low and intermediate strain amplitudes, where dislocation structures which localize deformation are expected to be present. In general, the cyclic response of coarse-grained copper shows a much more pronounced cyclic hardening and higher saturation stresses than those for fine-grained copper. This behavior is associated with a well defined hard [111]-[100] fiber texture, inherited in the coarse-grained material after annealing at relatively high temperatures. The multiple slip associated with the [111]-[001] oriented grains homogenizes the deformation very early, resulting in strong cyclic hardening, and a faster substructure evolution into cell structure. C1 UNIV PENN, DEPT MAT SCI & ENGN, PHILADELPHIA, PA 19104 USA. LOS ALAMOS NATL LAB, DIV MAT SCI & TECHNOL, LOS ALAMOS, NM 87545 USA. UNIV PENN, DEPT MECH ENGN & APPL MECH, PHILADELPHIA, PA 19104 USA. RI Rollett, Anthony/A-4096-2012; Llanes, Luis/H-9761-2015 OI Rollett, Anthony/0000-0003-4445-2191; Llanes, Luis/0000-0003-1054-1073 NR 50 TC 48 Z9 48 U1 0 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD SEP PY 1993 VL 41 IS 9 BP 2667 EP 2679 DI 10.1016/0956-7151(93)90136-G PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LR484 UT WOS:A1993LR48400015 ER PT J AU DAUSKARDT, RH AF DAUSKARDT, RH TI A FRICTIONAL-WEAR MECHANISM FOR FATIGUE-CRACK GROWTH IN GRAIN BRIDGING CERAMICS SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID FRACTURE-RESISTANCE MECHANISM; CYCLIC FATIGUE; PROPAGATION; TOUGHNESS; ALUMINA AB A frictional-wear mechanism to account for cyclic fatigue degradation in polycrystalline ceramics exhibiting grain bridging as the principal toughening mechanism is contemplated. The mechanism is based on repetitive sliding wear degradation of frictional grain bridges which reduces the toughening capacity from bridging under cyclic loads. A micromechanical model is developed to relate the reduction in the frictional pullout stress of bridging grains to material removed by wear processes at the grain/matrix interface. The model provides an insight into the effects of salient mechanical and microstructural variables such as wear rate at the grain/matrix interface, initial residual stress of bridging grains, and the grain size, on fatigue-crack growth behavior. Results of the analysis are compared to experimentally observed fatigue-crack growth rates in coarse grained alumina and silicon nitride and implications of the predicted crack-growth behavior discussed. C1 UNIV CALIF BERKELEY, DEPT MAT SCI & MINERAL ENGN, BERKELEY, CA 94720 USA. RP DAUSKARDT, RH (reprint author), LAWRENCE BERKELEY LAB, CTR ADV MAT, DIV MAT SCI, BERKELEY, CA 94720 USA. NR 35 TC 101 Z9 101 U1 4 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD SEP PY 1993 VL 41 IS 9 BP 2765 EP 2781 DI 10.1016/0956-7151(93)90145-I PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LR484 UT WOS:A1993LR48400024 ER PT J AU HALLER, EE AF HALLER, EE TI PHYSICS WITH CHEMICALLY AND ISOTOPICALLY PURE SEMICONDUCTORS SO ACTA PHYSICA POLONICA A LA English DT Article ID ACCEPTOR COMPLEXES; GERMANIUM; HYDROGEN; ISOTOPE; SILICON; CRYSTALS; SHALLOW; SHIFTS AB Chemically and isotopically pure semiconductors offer a wealth of interesting physics. We review a number of impurity complexes which were discovered in ultra-pure germanium. They have led the way to the widely pursued studies of hydrogen in numerous semiconductors. Isotope related effects and processes include neutron transmutation doping, a technique used for a number of silicon and germanium devices. Isotopically pure and deliberately mixed crystals of germanium have been grown recently and have been used to study the dependence of the indirect bandgap and phonon properties on the mass and mass disorder of the nuclei. The large number of stable isotopes of the various semiconductors present a great potential for basic and applied studies. Semiconductor isotope engineering may become a reality because of the new economic and political world order. C1 UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. RP HALLER, EE (reprint author), LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NR 52 TC 0 Z9 0 U1 1 U2 1 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, PL-02-668 WARSAW, POLAND SN 0587-4246 EI 1898-794X J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD SEP PY 1993 VL 84 IS 3 BP 395 EP 408 PG 14 WC Physics, Multidisciplinary SC Physics GA MF434 UT WOS:A1993MF43400002 ER PT J AU GILLILAND, GD WOLFORD, DJ HJALMARSON, HP PETROVIC, MS KLEM, J KUECH, TF NORTHROP, GA BRADLEY, JA AF GILLILAND, GD WOLFORD, DJ HJALMARSON, HP PETROVIC, MS KLEM, J KUECH, TF NORTHROP, GA BRADLEY, JA TI OPTICALLY-DETERMINED EXCITON TRANSPORT IN GAAS STRUCTURES SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT 22ND INTERNATIONAL SCHOOL ON PHYSICS OF SEMICONDUCTING COMPOUNDS CY MAY 22-28, 1993 CL JASZOWIEC, POLAND SP POLISH ACAD SCI, INST PHYS, WARSAW UNIV, FAC PHYS, EUROPEAN COMMUNITIES, COMMISS THIRTEEN, POLISH STATE COMM SCI RES, POLISH MINIST EDUC, STEFAN BATORY FDN, AMER PHYS SOC, INT PHYS FORUM, PRO PHYS FDN ID QUANTUM-WELL STRUCTURES; DOUBLE HETEROSTRUCTURES; DIFFUSION; STATES AB We have used an all-optical photoluminescence-imaging technique to measure excitonic transport in three types of GaAs structures in which the excitonic transitions vary from allowed direct-gap excitons to forbidden, doubly-indirect Type-II excitons. We find remarkable differences in the transport properties of these excitons. Our studies show that bulk free-exciton transport exhibits an anomalous laser power-dependent diffusivity, whereas quasi-2D interfacial excitons and Type-II cross-interface excitons do not. Additionally, we observe localization of cross-interface excitons at the potential disorder induced by the heterointerface roughness. C1 IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP GILLILAND, GD (reprint author), EMORY UNIV,DEPT PHYS,ATLANTA,GA 30322, USA. NR 20 TC 2 Z9 2 U1 2 U2 4 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, 02-668 WARSAW, POLAND SN 0587-4246 J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD SEP PY 1993 VL 84 IS 3 BP 409 EP 417 PG 9 WC Physics, Multidisciplinary SC Physics GA MF434 UT WOS:A1993MF43400003 ER PT J AU BELL, GI BIVINS, RL LOUCK, JD METROPOLIS, N STEIN, ML AF BELL, GI BIVINS, RL LOUCK, JD METROPOLIS, N STEIN, ML TI PROPERTIES OF WORDS ON 4 LETTERS FROM THOSE ON 2 LETTERS WITH AN APPLICATION TO DNA-SEQUENCES SO ADVANCES IN APPLIED MATHEMATICS LA English DT Article ID GENETIC-VARIATION RP BELL, GI (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544, USA. NR 26 TC 2 Z9 2 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 0196-8858 J9 ADV APPL MATH JI Adv. Appl. Math. PD SEP PY 1993 VL 14 IS 3 BP 348 EP 367 DI 10.1006/aama.1993.1017 PG 20 WC Mathematics, Applied SC Mathematics GA LP789 UT WOS:A1993LP78900004 ER PT J AU HAYNES, CA BENITEZ, FJ BLANCH, HW PRAUSNITZ, JM AF HAYNES, CA BENITEZ, FJ BLANCH, HW PRAUSNITZ, JM TI APPLICATION OF INTEGRAL-EQUATION THEORY TO AQUEOUS 2-PHASE PARTITIONING SYSTEMS SO AICHE JOURNAL LA English DT Article ID MEAN SPHERICAL MODEL; EXCESS GIBBS ENERGY; POLY(ETHYLENE GLYCOL) DEXTRAN; OPTIMIZED CLUSTER EXPANSIONS; LOCAL COMPOSITION MODEL; THERMODYNAMIC PROPERTIES; POLYMER SYSTEMS; ACTIVITY-COEFFICIENTS; ELECTROLYTE-SOLUTIONS; PHASE-SEPARATION AB A molecular-thermodynamic model is developed for representing thermodynamic properties of aqueous two-phase systems containing polymers, electrolytes, and proteins. The model is based on McMillan-Mayer solution theory and the generalized mean-spherical approximation to account for electrostatic forces between unlike ions. The Boublik-Mansoori equation of state for hard-sphere mixtures is coupled with the osmotic virial expansion truncated after the second-virial terms to account for short-range forces between molecules. Osmotic second virial coefficients are reported from low-angle laser-light scattering (LALLS) data for binary and ternary aqueous solutions containing polymers and proteins. Ion-polymer specific-interaction coefficients are determined from osmotic-pressure data for aqueous solutions containing a water-soluble polymer and an alkali chloride, phosphate or sulfate salt. When coupled with LALLS and osmotic-pressure data reported here, the model is used to predict liquid-liquid equilibria, protein partition coefficients, and electrostatic potentials between phases for both polymer-polymer and polymer-salt aqueous two-phase systems. For bovine serum albumin, lysozyme, and alpha-chymotrypsin, predicted partition coefficients are in excellent agreement with experiment. C1 LAWRENCE BERKELEY LAB,DEPT CHEM ENGN,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI BENITEZ, JAVIER/D-8934-2016 NR 124 TC 70 Z9 70 U1 1 U2 15 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD SEP PY 1993 VL 39 IS 9 BP 1539 EP 1557 DI 10.1002/aic.690390913 PG 19 WC Engineering, Chemical SC Engineering GA LW002 UT WOS:A1993LW00200012 ER PT J AU ROCSKAY, AZ ROBINS, TG ECHEVERRIA, D SCHORK, MA SEIXAS, NS WHITE, RF PROCTOR, SP AF ROCSKAY, AZ ROBINS, TG ECHEVERRIA, D SCHORK, MA SEIXAS, NS WHITE, RF PROCTOR, SP TI ESTIMATION OF CUMULATIVE EXPOSURES TO NAPHTHA AT AN AUTOMOBILE FUEL-INJECTOR MANUFACTURING PLANT SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article ID SOLVENT AB As part of an epidemiologic study of neuropsychological and renal effects of occupational exposure to organic solvents, estimates of cumulative exposure to naphtha were derived for workers at an automobile fuel-injector manufacturing plant. The approach to exposure estimation was relatively unusual in three respects: (1) a marked association between indoor naphtha air concentration and outdoor temperature was modeled and applied to detailed historical temperature data to calculate cumulative exposure estimates; (2) the large number of investigator-generated air samples allowed the use of analyses of variance to compare alternative job-grouping schemes; and (3) the young age of the plant and few process changes allowed for historical exposure estimates with a high degree of confidence. The derived estimates of cumulative exposure appear to offer a firm basis for epidemiologic analyses of exposure-health outcome relationships. C1 BATTELLE SEATTLE RES CTR,SEATTLE,WA 98105. UNIV MICHIGAN,SCH PUBL HLTH,DEPT BIOSTAT,ANN ARBOR,MI 48109. BOSTON UNIV,MED CTR,DEPT NEUROL,BOSTON,MA 02118. RP ROCSKAY, AZ (reprint author), UNIV MICHIGAN,SCH PUBL HLTH,DEPT ENVIRONM & IND HLTH,ANN ARBOR,MI 48109, USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD SEP PY 1993 VL 54 IS 9 BP 480 EP 487 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA MK310 UT WOS:A1993MK31000004 PM 8379495 ER PT J AU ETTINGER, HJ AF ETTINGER, HJ TI COMMUNICATIONS - AN ASSOCIATION ESSENTIAL SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Editorial Material RP ETTINGER, HJ (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD SEP PY 1993 VL 54 IS 9 BP A281 EP A282 PG 2 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA MK310 UT WOS:A1993MK31000001 ER PT J AU NAKAMURA, H SAKAMOTO, M COLLINS, C DOGGETT, N GINGRICH, J WHEELOCK, M JOHNSON, K WALDMAN, F PINKEL, D GRAY, JW AF NAKAMURA, H SAKAMOTO, M COLLINS, C DOGGETT, N GINGRICH, J WHEELOCK, M JOHNSON, K WALDMAN, F PINKEL, D GRAY, JW TI EXPRESSION, GENE COPY NUMBER, AND ABERRATIONS OF THE HUMAN E-CADHERIN GENE IN BREAST-CANCER SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DIV MOLEC CYTOMETRY,SAN FRANCISCO,CA 94143. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV TOLEDO,TOLEDO,OH 43606. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 27 EP 27 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500025 ER PT J AU DEININGER, P SHAIKH, T BAZAN, H SHEN, M BATZER, M AF DEININGER, P SHAIKH, T BAZAN, H SHEN, M BATZER, M TI THE EVOLUTION OF HUMAN ALU REPEATS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LSU MED CTR,DEPT BIOCHEM & MOLEC BIOL,NEW ORLEANS,LA. LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 70 EP 70 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500071 ER PT J AU WYROBEK, AJ ROBBINS, WA TANG, C KOBAYASHI, A BAULCH, J WEIER, HU PINKEL, D AF WYROBEK, AJ ROBBINS, WA TANG, C KOBAYASHI, A BAULCH, J WEIER, HU PINKEL, D TI HIERARCHICAL ORGANIZATION OF HUMAN SPERM CHROMATIN IS A CRITICAL FACTOR IN THE DETECTION OF CHROMOSOMAL ANEUPLOIDIES BY FLUORESCENCE IN-SITU HYBRIDIZATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL PROGRAM,LIVERMORE,CA 94550. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. NR 0 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 130 EP 130 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500129 ER PT J AU MOHRENWEISER, HW TSUJIMOTO, S ASHWORTH, L GORDON, L CARRANO, AV BRANDRIFF, B AF MOHRENWEISER, HW TSUJIMOTO, S ASHWORTH, L GORDON, L CARRANO, AV BRANDRIFF, B TI COINTEGRATION OF PHYSICAL AND GENETIC-MARKERS ONTO THE COSMID CONTIG MAP SPANNING HUMAN CHROMOSOME-19 SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 189 EP 189 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500191 ER PT J AU BUCKLER, AJ STOTLER, CJ RUTTER, JL MURRELL, J TROFATTER, JA MCCORMICK, MK DEAVEN, L MOYZIS, RK GUSELLA, JF AF BUCKLER, AJ STOTLER, CJ RUTTER, JL MURRELL, J TROFATTER, JA MCCORMICK, MK DEAVEN, L MOYZIS, RK GUSELLA, JF TI CHROMOSOME-SPECIFIC LIBRARIES OF EXONS AND HIGH-RESOLUTION TRANSCRIPTION MAPS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 MASSACHUSETTS GEN HOSP,MOLEC NEUROGENET LAB,BOSTON,MA 02114. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. NR 0 TC 0 Z9 0 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 192 EP 192 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500190 ER PT J AU OKINAKA, RT LAUBSCHER, KH SENA, AP AF OKINAKA, RT LAUBSCHER, KH SENA, AP TI EVIDENCE FOR MUTATIONS WITHIN THE ERCC5 GENE IN XERODERMA-PIGMENTOSUM GROUP-G PATIENT SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 340 EP 340 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500340 ER PT J AU CHEN, E CLEAVER, JE WEBER, CA WILLIAMS, ML PACKMAN, S PRICE, VH AF CHEN, E CLEAVER, JE WEBER, CA WILLIAMS, ML PACKMAN, S PRICE, VH TI TRICHOTHIODYSTROPHY - BIOCHEMICAL AND MOLECULAR CHARACTERIZATION AND CENTRAL-NERVOUS-SYSTEM IMAGING OF 2 SIBLINGS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,SAN FRANCISCO,CA 94143. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD SEP PY 1993 VL 53 IS 3 SU S BP 416 EP 416 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA LW335 UT WOS:A1993LW33500414 ER EF